Mercurial > hg > CbC > CbC_gcc
diff gcc/ada/exp_ch4.adb @ 111:04ced10e8804
gcc 7
| author | kono |
|---|---|
| date | Fri, 27 Oct 2017 22:46:09 +0900 |
| parents | |
| children | 84e7813d76e9 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gcc/ada/exp_ch4.adb Fri Oct 27 22:46:09 2017 +0900 @@ -0,0 +1,13960 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ C H 4 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2017, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +with Atree; use Atree; +with Checks; use Checks; +with Debug; use Debug; +with Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Exp_Aggr; use Exp_Aggr; +with Exp_Atag; use Exp_Atag; +with Exp_Ch2; use Exp_Ch2; +with Exp_Ch3; use Exp_Ch3; +with Exp_Ch6; use Exp_Ch6; +with Exp_Ch7; use Exp_Ch7; +with Exp_Ch9; use Exp_Ch9; +with Exp_Disp; use Exp_Disp; +with Exp_Fixd; use Exp_Fixd; +with Exp_Intr; use Exp_Intr; +with Exp_Pakd; use Exp_Pakd; +with Exp_Tss; use Exp_Tss; +with Exp_Util; use Exp_Util; +with Freeze; use Freeze; +with Inline; use Inline; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Par_SCO; use Par_SCO; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Aux; use Sem_Aux; +with Sem_Cat; use Sem_Cat; +with Sem_Ch3; use Sem_Ch3; +with Sem_Ch13; use Sem_Ch13; +with Sem_Eval; use Sem_Eval; +with Sem_Res; use Sem_Res; +with Sem_Type; use Sem_Type; +with Sem_Util; use Sem_Util; +with Sem_Warn; use Sem_Warn; +with Sinfo; use Sinfo; +with Snames; use Snames; +with Stand; use Stand; +with SCIL_LL; use SCIL_LL; +with Targparm; use Targparm; +with Tbuild; use Tbuild; +with Ttypes; use Ttypes; +with Uintp; use Uintp; +with Urealp; use Urealp; +with Validsw; use Validsw; + +package body Exp_Ch4 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Binary_Op_Validity_Checks (N : Node_Id); + pragma Inline (Binary_Op_Validity_Checks); + -- Performs validity checks for a binary operator + + procedure Build_Boolean_Array_Proc_Call + (N : Node_Id; + Op1 : Node_Id; + Op2 : Node_Id); + -- If a boolean array assignment can be done in place, build call to + -- corresponding library procedure. + + procedure Displace_Allocator_Pointer (N : Node_Id); + -- Ada 2005 (AI-251): Subsidiary procedure to Expand_N_Allocator and + -- Expand_Allocator_Expression. Allocating class-wide interface objects + -- this routine displaces the pointer to the allocated object to reference + -- the component referencing the corresponding secondary dispatch table. + + procedure Expand_Allocator_Expression (N : Node_Id); + -- Subsidiary to Expand_N_Allocator, for the case when the expression + -- is a qualified expression or an aggregate. + + procedure Expand_Array_Comparison (N : Node_Id); + -- This routine handles expansion of the comparison operators (N_Op_Lt, + -- N_Op_Le, N_Op_Gt, N_Op_Ge) when operating on an array type. The basic + -- code for these operators is similar, differing only in the details of + -- the actual comparison call that is made. Special processing (call a + -- run-time routine) + + function Expand_Array_Equality + (Nod : Node_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Bodies : List_Id; + Typ : Entity_Id) return Node_Id; + -- Expand an array equality into a call to a function implementing this + -- equality, and a call to it. Loc is the location for the generated nodes. + -- Lhs and Rhs are the array expressions to be compared. Bodies is a list + -- on which to attach bodies of local functions that are created in the + -- process. It is the responsibility of the caller to insert those bodies + -- at the right place. Nod provides the Sloc value for the generated code. + -- Normally the types used for the generated equality routine are taken + -- from Lhs and Rhs. However, in some situations of generated code, the + -- Etype fields of Lhs and Rhs are not set yet. In such cases, Typ supplies + -- the type to be used for the formal parameters. + + procedure Expand_Boolean_Operator (N : Node_Id); + -- Common expansion processing for Boolean operators (And, Or, Xor) for the + -- case of array type arguments. + + procedure Expand_Nonbinary_Modular_Op (N : Node_Id); + -- When generating C code, convert nonbinary modular arithmetic operations + -- into code that relies on the front-end expansion of operator Mod. No + -- expansion is performed if N is not a nonbinary modular operand. + + procedure Expand_Short_Circuit_Operator (N : Node_Id); + -- Common expansion processing for short-circuit boolean operators + + procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id); + -- Deal with comparison in MINIMIZED/ELIMINATED overflow mode. This is + -- where we allow comparison of "out of range" values. + + function Expand_Composite_Equality + (Nod : Node_Id; + Typ : Entity_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Bodies : List_Id) return Node_Id; + -- Local recursive function used to expand equality for nested composite + -- types. Used by Expand_Record/Array_Equality, Bodies is a list on which + -- to attach bodies of local functions that are created in the process. It + -- is the responsibility of the caller to insert those bodies at the right + -- place. Nod provides the Sloc value for generated code. Lhs and Rhs are + -- the left and right sides for the comparison, and Typ is the type of the + -- objects to compare. + + procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id); + -- Routine to expand concatenation of a sequence of two or more operands + -- (in the list Operands) and replace node Cnode with the result of the + -- concatenation. The operands can be of any appropriate type, and can + -- include both arrays and singleton elements. + + procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id); + -- N is an N_In membership test mode, with the overflow check mode set to + -- MINIMIZED or ELIMINATED, and the type of the left operand is a signed + -- integer type. This is a case where top level processing is required to + -- handle overflow checks in subtrees. + + procedure Fixup_Universal_Fixed_Operation (N : Node_Id); + -- N is a N_Op_Divide or N_Op_Multiply node whose result is universal + -- fixed. We do not have such a type at runtime, so the purpose of this + -- routine is to find the real type by looking up the tree. We also + -- determine if the operation must be rounded. + + function Has_Inferable_Discriminants (N : Node_Id) return Boolean; + -- Ada 2005 (AI-216): A view of an Unchecked_Union object has inferable + -- discriminants if it has a constrained nominal type, unless the object + -- is a component of an enclosing Unchecked_Union object that is subject + -- to a per-object constraint and the enclosing object lacks inferable + -- discriminants. + -- + -- An expression of an Unchecked_Union type has inferable discriminants + -- if it is either a name of an object with inferable discriminants or a + -- qualified expression whose subtype mark denotes a constrained subtype. + + procedure Insert_Dereference_Action (N : Node_Id); + -- N is an expression whose type is an access. When the type of the + -- associated storage pool is derived from Checked_Pool, generate a + -- call to the 'Dereference' primitive operation. + + function Make_Array_Comparison_Op + (Typ : Entity_Id; + Nod : Node_Id) return Node_Id; + -- Comparisons between arrays are expanded in line. This function produces + -- the body of the implementation of (a > b), where a and b are one- + -- dimensional arrays of some discrete type. The original node is then + -- expanded into the appropriate call to this function. Nod provides the + -- Sloc value for the generated code. + + function Make_Boolean_Array_Op + (Typ : Entity_Id; + N : Node_Id) return Node_Id; + -- Boolean operations on boolean arrays are expanded in line. This function + -- produce the body for the node N, which is (a and b), (a or b), or (a xor + -- b). It is used only the normal case and not the packed case. The type + -- involved, Typ, is the Boolean array type, and the logical operations in + -- the body are simple boolean operations. Note that Typ is always a + -- constrained type (the caller has ensured this by using + -- Convert_To_Actual_Subtype if necessary). + + function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean; + -- For signed arithmetic operations when the current overflow mode is + -- MINIMIZED or ELIMINATED, we must call Apply_Arithmetic_Overflow_Checks + -- as the first thing we do. We then return. We count on the recursive + -- apparatus for overflow checks to call us back with an equivalent + -- operation that is in CHECKED mode, avoiding a recursive entry into this + -- routine, and that is when we will proceed with the expansion of the + -- operator (e.g. converting X+0 to X, or X**2 to X*X). We cannot do + -- these optimizations without first making this check, since there may be + -- operands further down the tree that are relying on the recursive calls + -- triggered by the top level nodes to properly process overflow checking + -- and remaining expansion on these nodes. Note that this call back may be + -- skipped if the operation is done in Bignum mode but that's fine, since + -- the Bignum call takes care of everything. + + procedure Optimize_Length_Comparison (N : Node_Id); + -- Given an expression, if it is of the form X'Length op N (or the other + -- way round), where N is known at compile time to be 0 or 1, and X is a + -- simple entity, and op is a comparison operator, optimizes it into a + -- comparison of First and Last. + + procedure Process_If_Case_Statements (N : Node_Id; Stmts : List_Id); + -- Inspect and process statement list Stmt of if or case expression N for + -- transient objects. If such objects are found, the routine generates code + -- to clean them up when the context of the expression is evaluated. + + procedure Process_Transient_In_Expression + (Obj_Decl : Node_Id; + Expr : Node_Id; + Stmts : List_Id); + -- Subsidiary routine to the expansion of expression_with_actions, if and + -- case expressions. Generate all necessary code to finalize a transient + -- object when the enclosing context is elaborated or evaluated. Obj_Decl + -- denotes the declaration of the transient object, which is usually the + -- result of a controlled function call. Expr denotes the expression with + -- actions, if expression, or case expression node. Stmts denotes the + -- statement list which contains Decl, either at the top level or within a + -- nested construct. + + procedure Rewrite_Comparison (N : Node_Id); + -- If N is the node for a comparison whose outcome can be determined at + -- compile time, then the node N can be rewritten with True or False. If + -- the outcome cannot be determined at compile time, the call has no + -- effect. If N is a type conversion, then this processing is applied to + -- its expression. If N is neither comparison nor a type conversion, the + -- call has no effect. + + procedure Tagged_Membership + (N : Node_Id; + SCIL_Node : out Node_Id; + Result : out Node_Id); + -- Construct the expression corresponding to the tagged membership test. + -- Deals with a second operand being (or not) a class-wide type. + + function Safe_In_Place_Array_Op + (Lhs : Node_Id; + Op1 : Node_Id; + Op2 : Node_Id) return Boolean; + -- In the context of an assignment, where the right-hand side is a boolean + -- operation on arrays, check whether operation can be performed in place. + + procedure Unary_Op_Validity_Checks (N : Node_Id); + pragma Inline (Unary_Op_Validity_Checks); + -- Performs validity checks for a unary operator + + ------------------------------- + -- Binary_Op_Validity_Checks -- + ------------------------------- + + procedure Binary_Op_Validity_Checks (N : Node_Id) is + begin + if Validity_Checks_On and Validity_Check_Operands then + Ensure_Valid (Left_Opnd (N)); + Ensure_Valid (Right_Opnd (N)); + end if; + end Binary_Op_Validity_Checks; + + ------------------------------------ + -- Build_Boolean_Array_Proc_Call -- + ------------------------------------ + + procedure Build_Boolean_Array_Proc_Call + (N : Node_Id; + Op1 : Node_Id; + Op2 : Node_Id) + is + Loc : constant Source_Ptr := Sloc (N); + Kind : constant Node_Kind := Nkind (Expression (N)); + Target : constant Node_Id := + Make_Attribute_Reference (Loc, + Prefix => Name (N), + Attribute_Name => Name_Address); + + Arg1 : Node_Id := Op1; + Arg2 : Node_Id := Op2; + Call_Node : Node_Id; + Proc_Name : Entity_Id; + + begin + if Kind = N_Op_Not then + if Nkind (Op1) in N_Binary_Op then + + -- Use negated version of the binary operators + + if Nkind (Op1) = N_Op_And then + Proc_Name := RTE (RE_Vector_Nand); + + elsif Nkind (Op1) = N_Op_Or then + Proc_Name := RTE (RE_Vector_Nor); + + else pragma Assert (Nkind (Op1) = N_Op_Xor); + Proc_Name := RTE (RE_Vector_Xor); + end if; + + Call_Node := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Name, Loc), + + Parameter_Associations => New_List ( + Target, + Make_Attribute_Reference (Loc, + Prefix => Left_Opnd (Op1), + Attribute_Name => Name_Address), + + Make_Attribute_Reference (Loc, + Prefix => Right_Opnd (Op1), + Attribute_Name => Name_Address), + + Make_Attribute_Reference (Loc, + Prefix => Left_Opnd (Op1), + Attribute_Name => Name_Length))); + + else + Proc_Name := RTE (RE_Vector_Not); + + Call_Node := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Name, Loc), + Parameter_Associations => New_List ( + Target, + + Make_Attribute_Reference (Loc, + Prefix => Op1, + Attribute_Name => Name_Address), + + Make_Attribute_Reference (Loc, + Prefix => Op1, + Attribute_Name => Name_Length))); + end if; + + else + -- We use the following equivalences: + + -- (not X) or (not Y) = not (X and Y) = Nand (X, Y) + -- (not X) and (not Y) = not (X or Y) = Nor (X, Y) + -- (not X) xor (not Y) = X xor Y + -- X xor (not Y) = not (X xor Y) = Nxor (X, Y) + + if Nkind (Op1) = N_Op_Not then + Arg1 := Right_Opnd (Op1); + Arg2 := Right_Opnd (Op2); + + if Kind = N_Op_And then + Proc_Name := RTE (RE_Vector_Nor); + elsif Kind = N_Op_Or then + Proc_Name := RTE (RE_Vector_Nand); + else + Proc_Name := RTE (RE_Vector_Xor); + end if; + + else + if Kind = N_Op_And then + Proc_Name := RTE (RE_Vector_And); + elsif Kind = N_Op_Or then + Proc_Name := RTE (RE_Vector_Or); + elsif Nkind (Op2) = N_Op_Not then + Proc_Name := RTE (RE_Vector_Nxor); + Arg2 := Right_Opnd (Op2); + else + Proc_Name := RTE (RE_Vector_Xor); + end if; + end if; + + Call_Node := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Name, Loc), + Parameter_Associations => New_List ( + Target, + Make_Attribute_Reference (Loc, + Prefix => Arg1, + Attribute_Name => Name_Address), + Make_Attribute_Reference (Loc, + Prefix => Arg2, + Attribute_Name => Name_Address), + Make_Attribute_Reference (Loc, + Prefix => Arg1, + Attribute_Name => Name_Length))); + end if; + + Rewrite (N, Call_Node); + Analyze (N); + + exception + when RE_Not_Available => + return; + end Build_Boolean_Array_Proc_Call; + + -------------------------------- + -- Displace_Allocator_Pointer -- + -------------------------------- + + procedure Displace_Allocator_Pointer (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Orig_Node : constant Node_Id := Original_Node (N); + Dtyp : Entity_Id; + Etyp : Entity_Id; + PtrT : Entity_Id; + + begin + -- Do nothing in case of VM targets: the virtual machine will handle + -- interfaces directly. + + if not Tagged_Type_Expansion then + return; + end if; + + pragma Assert (Nkind (N) = N_Identifier + and then Nkind (Orig_Node) = N_Allocator); + + PtrT := Etype (Orig_Node); + Dtyp := Available_View (Designated_Type (PtrT)); + Etyp := Etype (Expression (Orig_Node)); + + if Is_Class_Wide_Type (Dtyp) and then Is_Interface (Dtyp) then + + -- If the type of the allocator expression is not an interface type + -- we can generate code to reference the record component containing + -- the pointer to the secondary dispatch table. + + if not Is_Interface (Etyp) then + declare + Saved_Typ : constant Entity_Id := Etype (Orig_Node); + + begin + -- 1) Get access to the allocated object + + Rewrite (N, + Make_Explicit_Dereference (Loc, Relocate_Node (N))); + Set_Etype (N, Etyp); + Set_Analyzed (N); + + -- 2) Add the conversion to displace the pointer to reference + -- the secondary dispatch table. + + Rewrite (N, Convert_To (Dtyp, Relocate_Node (N))); + Analyze_And_Resolve (N, Dtyp); + + -- 3) The 'access to the secondary dispatch table will be used + -- as the value returned by the allocator. + + Rewrite (N, + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (N), + Attribute_Name => Name_Access)); + Set_Etype (N, Saved_Typ); + Set_Analyzed (N); + end; + + -- If the type of the allocator expression is an interface type we + -- generate a run-time call to displace "this" to reference the + -- component containing the pointer to the secondary dispatch table + -- or else raise Constraint_Error if the actual object does not + -- implement the target interface. This case corresponds to the + -- following example: + + -- function Op (Obj : Iface_1'Class) return access Iface_2'Class is + -- begin + -- return new Iface_2'Class'(Obj); + -- end Op; + + else + Rewrite (N, + Unchecked_Convert_To (PtrT, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (RE_Displace), Loc), + Parameter_Associations => New_List ( + Unchecked_Convert_To (RTE (RE_Address), + Relocate_Node (N)), + + New_Occurrence_Of + (Elists.Node + (First_Elmt + (Access_Disp_Table (Etype (Base_Type (Dtyp))))), + Loc))))); + Analyze_And_Resolve (N, PtrT); + end if; + end if; + end Displace_Allocator_Pointer; + + --------------------------------- + -- Expand_Allocator_Expression -- + --------------------------------- + + procedure Expand_Allocator_Expression (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Exp : constant Node_Id := Expression (Expression (N)); + PtrT : constant Entity_Id := Etype (N); + DesigT : constant Entity_Id := Designated_Type (PtrT); + + procedure Apply_Accessibility_Check + (Ref : Node_Id; + Built_In_Place : Boolean := False); + -- Ada 2005 (AI-344): For an allocator with a class-wide designated + -- type, generate an accessibility check to verify that the level of the + -- type of the created object is not deeper than the level of the access + -- type. If the type of the qualified expression is class-wide, then + -- always generate the check (except in the case where it is known to be + -- unnecessary, see comment below). Otherwise, only generate the check + -- if the level of the qualified expression type is statically deeper + -- than the access type. + -- + -- Although the static accessibility will generally have been performed + -- as a legality check, it won't have been done in cases where the + -- allocator appears in generic body, so a run-time check is needed in + -- general. One special case is when the access type is declared in the + -- same scope as the class-wide allocator, in which case the check can + -- never fail, so it need not be generated. + -- + -- As an open issue, there seem to be cases where the static level + -- associated with the class-wide object's underlying type is not + -- sufficient to perform the proper accessibility check, such as for + -- allocators in nested subprograms or accept statements initialized by + -- class-wide formals when the actual originates outside at a deeper + -- static level. The nested subprogram case might require passing + -- accessibility levels along with class-wide parameters, and the task + -- case seems to be an actual gap in the language rules that needs to + -- be fixed by the ARG. ??? + + ------------------------------- + -- Apply_Accessibility_Check -- + ------------------------------- + + procedure Apply_Accessibility_Check + (Ref : Node_Id; + Built_In_Place : Boolean := False) + is + Pool_Id : constant Entity_Id := Associated_Storage_Pool (PtrT); + Cond : Node_Id; + Fin_Call : Node_Id; + Free_Stmt : Node_Id; + Obj_Ref : Node_Id; + Stmts : List_Id; + + begin + if Ada_Version >= Ada_2005 + and then Is_Class_Wide_Type (DesigT) + and then Tagged_Type_Expansion + and then not Scope_Suppress.Suppress (Accessibility_Check) + and then + (Type_Access_Level (Etype (Exp)) > Type_Access_Level (PtrT) + or else + (Is_Class_Wide_Type (Etype (Exp)) + and then Scope (PtrT) /= Current_Scope)) + then + -- If the allocator was built in place, Ref is already a reference + -- to the access object initialized to the result of the allocator + -- (see Exp_Ch6.Make_Build_In_Place_Call_In_Allocator). We call + -- Remove_Side_Effects for cases where the build-in-place call may + -- still be the prefix of the reference (to avoid generating + -- duplicate calls). Otherwise, it is the entity associated with + -- the object containing the address of the allocated object. + + if Built_In_Place then + Remove_Side_Effects (Ref); + Obj_Ref := New_Copy_Tree (Ref); + else + Obj_Ref := New_Occurrence_Of (Ref, Loc); + end if; + + -- For access to interface types we must generate code to displace + -- the pointer to the base of the object since the subsequent code + -- references components located in the TSD of the object (which + -- is associated with the primary dispatch table --see a-tags.ads) + -- and also generates code invoking Free, which requires also a + -- reference to the base of the unallocated object. + + if Is_Interface (DesigT) and then Tagged_Type_Expansion then + Obj_Ref := + Unchecked_Convert_To (Etype (Obj_Ref), + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Base_Address), Loc), + Parameter_Associations => New_List ( + Unchecked_Convert_To (RTE (RE_Address), + New_Copy_Tree (Obj_Ref))))); + end if; + + -- Step 1: Create the object clean up code + + Stmts := New_List; + + -- Deallocate the object if the accessibility check fails. This + -- is done only on targets or profiles that support deallocation. + + -- Free (Obj_Ref); + + if RTE_Available (RE_Free) then + Free_Stmt := Make_Free_Statement (Loc, New_Copy_Tree (Obj_Ref)); + Set_Storage_Pool (Free_Stmt, Pool_Id); + + Append_To (Stmts, Free_Stmt); + + -- The target or profile cannot deallocate objects + + else + Free_Stmt := Empty; + end if; + + -- Finalize the object if applicable. Generate: + + -- [Deep_]Finalize (Obj_Ref.all); + + if Needs_Finalization (DesigT) then + Fin_Call := + Make_Final_Call + (Obj_Ref => + Make_Explicit_Dereference (Loc, New_Copy (Obj_Ref)), + Typ => DesigT); + + -- Guard against a missing [Deep_]Finalize when the designated + -- type was not properly frozen. + + if No (Fin_Call) then + Fin_Call := Make_Null_Statement (Loc); + end if; + + -- When the target or profile supports deallocation, wrap the + -- finalization call in a block to ensure proper deallocation + -- even if finalization fails. Generate: + + -- begin + -- <Fin_Call> + -- exception + -- when others => + -- <Free_Stmt> + -- raise; + -- end; + + if Present (Free_Stmt) then + Fin_Call := + Make_Block_Statement (Loc, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Fin_Call), + + Exception_Handlers => New_List ( + Make_Exception_Handler (Loc, + Exception_Choices => New_List ( + Make_Others_Choice (Loc)), + Statements => New_List ( + New_Copy_Tree (Free_Stmt), + Make_Raise_Statement (Loc)))))); + end if; + + Prepend_To (Stmts, Fin_Call); + end if; + + -- Signal the accessibility failure through a Program_Error + + Append_To (Stmts, + Make_Raise_Program_Error (Loc, + Condition => New_Occurrence_Of (Standard_True, Loc), + Reason => PE_Accessibility_Check_Failed)); + + -- Step 2: Create the accessibility comparison + + -- Generate: + -- Ref'Tag + + Obj_Ref := + Make_Attribute_Reference (Loc, + Prefix => Obj_Ref, + Attribute_Name => Name_Tag); + + -- For tagged types, determine the accessibility level by looking + -- at the type specific data of the dispatch table. Generate: + + -- Type_Specific_Data (Address (Ref'Tag)).Access_Level + + if Tagged_Type_Expansion then + Cond := Build_Get_Access_Level (Loc, Obj_Ref); + + -- Use a runtime call to determine the accessibility level when + -- compiling on virtual machine targets. Generate: + + -- Get_Access_Level (Ref'Tag) + + else + Cond := + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Get_Access_Level), Loc), + Parameter_Associations => New_List (Obj_Ref)); + end if; + + Cond := + Make_Op_Gt (Loc, + Left_Opnd => Cond, + Right_Opnd => + Make_Integer_Literal (Loc, Type_Access_Level (PtrT))); + + -- Due to the complexity and side effects of the check, utilize an + -- if statement instead of the regular Program_Error circuitry. + + Insert_Action (N, + Make_Implicit_If_Statement (N, + Condition => Cond, + Then_Statements => Stmts)); + end if; + end Apply_Accessibility_Check; + + -- Local variables + + Aggr_In_Place : constant Boolean := Is_Delayed_Aggregate (Exp); + Indic : constant Node_Id := Subtype_Mark (Expression (N)); + T : constant Entity_Id := Entity (Indic); + Adj_Call : Node_Id; + Node : Node_Id; + Tag_Assign : Node_Id; + Temp : Entity_Id; + Temp_Decl : Node_Id; + + TagT : Entity_Id := Empty; + -- Type used as source for tag assignment + + TagR : Node_Id := Empty; + -- Target reference for tag assignment + + -- Start of processing for Expand_Allocator_Expression + + begin + -- Handle call to C++ constructor + + if Is_CPP_Constructor_Call (Exp) then + Make_CPP_Constructor_Call_In_Allocator + (Allocator => N, + Function_Call => Exp); + return; + end if; + + -- In the case of an Ada 2012 allocator whose initial value comes from a + -- function call, pass "the accessibility level determined by the point + -- of call" (AI05-0234) to the function. Conceptually, this belongs in + -- Expand_Call but it couldn't be done there (because the Etype of the + -- allocator wasn't set then) so we generate the parameter here. See + -- the Boolean variable Defer in (a block within) Expand_Call. + + if Ada_Version >= Ada_2012 and then Nkind (Exp) = N_Function_Call then + declare + Subp : Entity_Id; + + begin + if Nkind (Name (Exp)) = N_Explicit_Dereference then + Subp := Designated_Type (Etype (Prefix (Name (Exp)))); + else + Subp := Entity (Name (Exp)); + end if; + + Subp := Ultimate_Alias (Subp); + + if Present (Extra_Accessibility_Of_Result (Subp)) then + Add_Extra_Actual_To_Call + (Subprogram_Call => Exp, + Extra_Formal => Extra_Accessibility_Of_Result (Subp), + Extra_Actual => Dynamic_Accessibility_Level (PtrT)); + end if; + end; + end if; + + -- Case of tagged type or type requiring finalization + + if Is_Tagged_Type (T) or else Needs_Finalization (T) then + + -- Ada 2005 (AI-318-02): If the initialization expression is a call + -- to a build-in-place function, then access to the allocated object + -- must be passed to the function. + + if Is_Build_In_Place_Function_Call (Exp) then + Make_Build_In_Place_Call_In_Allocator (N, Exp); + Apply_Accessibility_Check (N, Built_In_Place => True); + return; + + -- Ada 2005 (AI-318-02): Specialization of the previous case for + -- expressions containing a build-in-place function call whose + -- returned object covers interface types, and Expr has calls to + -- Ada.Tags.Displace to displace the pointer to the returned build- + -- in-place object to reference the secondary dispatch table of a + -- covered interface type. + + elsif Present (Unqual_BIP_Iface_Function_Call (Exp)) then + Make_Build_In_Place_Iface_Call_In_Allocator (N, Exp); + Apply_Accessibility_Check (N, Built_In_Place => True); + return; + end if; + + -- Actions inserted before: + -- Temp : constant ptr_T := new T'(Expression); + -- Temp._tag = T'tag; -- when not class-wide + -- [Deep_]Adjust (Temp.all); + + -- We analyze by hand the new internal allocator to avoid any + -- recursion and inappropriate call to Initialize. + + -- We don't want to remove side effects when the expression must be + -- built in place. In the case of a build-in-place function call, + -- that could lead to a duplication of the call, which was already + -- substituted for the allocator. + + if not Aggr_In_Place then + Remove_Side_Effects (Exp); + end if; + + Temp := Make_Temporary (Loc, 'P', N); + + -- For a class wide allocation generate the following code: + + -- type Equiv_Record is record ... end record; + -- implicit subtype CW is <Class_Wide_Subytpe>; + -- temp : PtrT := new CW'(CW!(expr)); + + if Is_Class_Wide_Type (T) then + Expand_Subtype_From_Expr (Empty, T, Indic, Exp); + + -- Ada 2005 (AI-251): If the expression is a class-wide interface + -- object we generate code to move up "this" to reference the + -- base of the object before allocating the new object. + + -- Note that Exp'Address is recursively expanded into a call + -- to Base_Address (Exp.Tag) + + if Is_Class_Wide_Type (Etype (Exp)) + and then Is_Interface (Etype (Exp)) + and then Tagged_Type_Expansion + then + Set_Expression + (Expression (N), + Unchecked_Convert_To (Entity (Indic), + Make_Explicit_Dereference (Loc, + Unchecked_Convert_To (RTE (RE_Tag_Ptr), + Make_Attribute_Reference (Loc, + Prefix => Exp, + Attribute_Name => Name_Address))))); + else + Set_Expression + (Expression (N), + Unchecked_Convert_To (Entity (Indic), Exp)); + end if; + + Analyze_And_Resolve (Expression (N), Entity (Indic)); + end if; + + -- Processing for allocators returning non-interface types + + if not Is_Interface (Directly_Designated_Type (PtrT)) then + if Aggr_In_Place then + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => New_Occurrence_Of (PtrT, Loc), + Expression => + Make_Allocator (Loc, + Expression => + New_Occurrence_Of (Etype (Exp), Loc))); + + -- Copy the Comes_From_Source flag for the allocator we just + -- built, since logically this allocator is a replacement of + -- the original allocator node. This is for proper handling of + -- restriction No_Implicit_Heap_Allocations. + + Set_Comes_From_Source + (Expression (Temp_Decl), Comes_From_Source (N)); + + Set_No_Initialization (Expression (Temp_Decl)); + Insert_Action (N, Temp_Decl); + + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); + + else + Node := Relocate_Node (N); + Set_Analyzed (Node); + + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (PtrT, Loc), + Expression => Node); + + Insert_Action (N, Temp_Decl); + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + end if; + + -- Ada 2005 (AI-251): Handle allocators whose designated type is an + -- interface type. In this case we use the type of the qualified + -- expression to allocate the object. + + else + declare + Def_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); + New_Decl : Node_Id; + + begin + New_Decl := + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Def_Id, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Null_Exclusion_Present => False, + Constant_Present => + Is_Access_Constant (Etype (N)), + Subtype_Indication => + New_Occurrence_Of (Etype (Exp), Loc))); + + Insert_Action (N, New_Decl); + + -- Inherit the allocation-related attributes from the original + -- access type. + + Set_Finalization_Master + (Def_Id, Finalization_Master (PtrT)); + + Set_Associated_Storage_Pool + (Def_Id, Associated_Storage_Pool (PtrT)); + + -- Declare the object using the previous type declaration + + if Aggr_In_Place then + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => New_Occurrence_Of (Def_Id, Loc), + Expression => + Make_Allocator (Loc, + New_Occurrence_Of (Etype (Exp), Loc))); + + -- Copy the Comes_From_Source flag for the allocator we just + -- built, since logically this allocator is a replacement of + -- the original allocator node. This is for proper handling + -- of restriction No_Implicit_Heap_Allocations. + + Set_Comes_From_Source + (Expression (Temp_Decl), Comes_From_Source (N)); + + Set_No_Initialization (Expression (Temp_Decl)); + Insert_Action (N, Temp_Decl); + + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); + + else + Node := Relocate_Node (N); + Set_Analyzed (Node); + + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Def_Id, Loc), + Expression => Node); + + Insert_Action (N, Temp_Decl); + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + end if; + + -- Generate an additional object containing the address of the + -- returned object. The type of this second object declaration + -- is the correct type required for the common processing that + -- is still performed by this subprogram. The displacement of + -- this pointer to reference the component associated with the + -- interface type will be done at the end of common processing. + + New_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Make_Temporary (Loc, 'P'), + Object_Definition => New_Occurrence_Of (PtrT, Loc), + Expression => + Unchecked_Convert_To (PtrT, + New_Occurrence_Of (Temp, Loc))); + + Insert_Action (N, New_Decl); + + Temp_Decl := New_Decl; + Temp := Defining_Identifier (New_Decl); + end; + end if; + + -- Generate the tag assignment + + -- Suppress the tag assignment for VM targets because VM tags are + -- represented implicitly in objects. + + if not Tagged_Type_Expansion then + null; + + -- Ada 2005 (AI-251): Suppress the tag assignment with class-wide + -- interface objects because in this case the tag does not change. + + elsif Is_Interface (Directly_Designated_Type (Etype (N))) then + pragma Assert (Is_Class_Wide_Type + (Directly_Designated_Type (Etype (N)))); + null; + + elsif Is_Tagged_Type (T) and then not Is_Class_Wide_Type (T) then + TagT := T; + TagR := New_Occurrence_Of (Temp, Loc); + + elsif Is_Private_Type (T) + and then Is_Tagged_Type (Underlying_Type (T)) + then + TagT := Underlying_Type (T); + TagR := + Unchecked_Convert_To (Underlying_Type (T), + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Temp, Loc))); + end if; + + if Present (TagT) then + declare + Full_T : constant Entity_Id := Underlying_Type (TagT); + + begin + Tag_Assign := + Make_Assignment_Statement (Loc, + Name => + Make_Selected_Component (Loc, + Prefix => TagR, + Selector_Name => + New_Occurrence_Of + (First_Tag_Component (Full_T), Loc)), + + Expression => + Unchecked_Convert_To (RTE (RE_Tag), + New_Occurrence_Of + (Elists.Node + (First_Elmt (Access_Disp_Table (Full_T))), Loc))); + end; + + -- The previous assignment has to be done in any case + + Set_Assignment_OK (Name (Tag_Assign)); + Insert_Action (N, Tag_Assign); + end if; + + -- Generate an Adjust call if the object will be moved. In Ada 2005, + -- the object may be inherently limited, in which case there is no + -- Adjust procedure, and the object is built in place. In Ada 95, the + -- object can be limited but not inherently limited if this allocator + -- came from a return statement (we're allocating the result on the + -- secondary stack). In that case, the object will be moved, so we do + -- want to Adjust. However, if it's a nonlimited build-in-place + -- function call, Adjust is not wanted. + + if Needs_Finalization (DesigT) + and then Needs_Finalization (T) + and then not Aggr_In_Place + and then not Is_Limited_View (T) + and then not Alloc_For_BIP_Return (N) + and then not Is_Build_In_Place_Function_Call (Expression (N)) + then + -- An unchecked conversion is needed in the classwide case because + -- the designated type can be an ancestor of the subtype mark of + -- the allocator. + + Adj_Call := + Make_Adjust_Call + (Obj_Ref => + Unchecked_Convert_To (T, + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Temp, Loc))), + Typ => T); + + if Present (Adj_Call) then + Insert_Action (N, Adj_Call); + end if; + end if; + + -- Note: the accessibility check must be inserted after the call to + -- [Deep_]Adjust to ensure proper completion of the assignment. + + Apply_Accessibility_Check (Temp); + + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + Analyze_And_Resolve (N, PtrT); + + -- Ada 2005 (AI-251): Displace the pointer to reference the record + -- component containing the secondary dispatch table of the interface + -- type. + + if Is_Interface (Directly_Designated_Type (PtrT)) then + Displace_Allocator_Pointer (N); + end if; + + -- Always force the generation of a temporary for aggregates when + -- generating C code, to simplify the work in the code generator. + + elsif Aggr_In_Place + or else (Modify_Tree_For_C and then Nkind (Exp) = N_Aggregate) + then + Temp := Make_Temporary (Loc, 'P', N); + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => New_Occurrence_Of (PtrT, Loc), + Expression => + Make_Allocator (Loc, + Expression => New_Occurrence_Of (Etype (Exp), Loc))); + + -- Copy the Comes_From_Source flag for the allocator we just built, + -- since logically this allocator is a replacement of the original + -- allocator node. This is for proper handling of restriction + -- No_Implicit_Heap_Allocations. + + Set_Comes_From_Source + (Expression (Temp_Decl), Comes_From_Source (N)); + + Set_No_Initialization (Expression (Temp_Decl)); + Insert_Action (N, Temp_Decl); + + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + Convert_Aggr_In_Allocator (N, Temp_Decl, Exp); + + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + Analyze_And_Resolve (N, PtrT); + + elsif Is_Access_Type (T) and then Can_Never_Be_Null (T) then + Install_Null_Excluding_Check (Exp); + + elsif Is_Access_Type (DesigT) + and then Nkind (Exp) = N_Allocator + and then Nkind (Expression (Exp)) /= N_Qualified_Expression + then + -- Apply constraint to designated subtype indication + + Apply_Constraint_Check + (Expression (Exp), Designated_Type (DesigT), No_Sliding => True); + + if Nkind (Expression (Exp)) = N_Raise_Constraint_Error then + + -- Propagate constraint_error to enclosing allocator + + Rewrite (Exp, New_Copy (Expression (Exp))); + end if; + + else + Build_Allocate_Deallocate_Proc (N, True); + + -- If we have: + -- type A is access T1; + -- X : A := new T2'(...); + -- T1 and T2 can be different subtypes, and we might need to check + -- both constraints. First check against the type of the qualified + -- expression. + + Apply_Constraint_Check (Exp, T, No_Sliding => True); + + if Do_Range_Check (Exp) then + Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed); + end if; + + -- A check is also needed in cases where the designated subtype is + -- constrained and differs from the subtype given in the qualified + -- expression. Note that the check on the qualified expression does + -- not allow sliding, but this check does (a relaxation from Ada 83). + + if Is_Constrained (DesigT) + and then not Subtypes_Statically_Match (T, DesigT) + then + Apply_Constraint_Check + (Exp, DesigT, No_Sliding => False); + + if Do_Range_Check (Exp) then + Generate_Range_Check (Exp, DesigT, CE_Range_Check_Failed); + end if; + end if; + + -- For an access to unconstrained packed array, GIGI needs to see an + -- expression with a constrained subtype in order to compute the + -- proper size for the allocator. + + if Is_Array_Type (T) + and then not Is_Constrained (T) + and then Is_Packed (T) + then + declare + ConstrT : constant Entity_Id := Make_Temporary (Loc, 'A'); + Internal_Exp : constant Node_Id := Relocate_Node (Exp); + begin + Insert_Action (Exp, + Make_Subtype_Declaration (Loc, + Defining_Identifier => ConstrT, + Subtype_Indication => + Make_Subtype_From_Expr (Internal_Exp, T))); + Freeze_Itype (ConstrT, Exp); + Rewrite (Exp, OK_Convert_To (ConstrT, Internal_Exp)); + end; + end if; + + -- Ada 2005 (AI-318-02): If the initialization expression is a call + -- to a build-in-place function, then access to the allocated object + -- must be passed to the function. + + if Is_Build_In_Place_Function_Call (Exp) then + Make_Build_In_Place_Call_In_Allocator (N, Exp); + end if; + end if; + + exception + when RE_Not_Available => + return; + end Expand_Allocator_Expression; + + ----------------------------- + -- Expand_Array_Comparison -- + ----------------------------- + + -- Expansion is only required in the case of array types. For the unpacked + -- case, an appropriate runtime routine is called. For packed cases, and + -- also in some other cases where a runtime routine cannot be called, the + -- form of the expansion is: + + -- [body for greater_nn; boolean_expression] + + -- The body is built by Make_Array_Comparison_Op, and the form of the + -- Boolean expression depends on the operator involved. + + procedure Expand_Array_Comparison (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Op1 : Node_Id := Left_Opnd (N); + Op2 : Node_Id := Right_Opnd (N); + Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); + Ctyp : constant Entity_Id := Component_Type (Typ1); + + Expr : Node_Id; + Func_Body : Node_Id; + Func_Name : Entity_Id; + + Comp : RE_Id; + + Byte_Addressable : constant Boolean := System_Storage_Unit = Byte'Size; + -- True for byte addressable target + + function Length_Less_Than_4 (Opnd : Node_Id) return Boolean; + -- Returns True if the length of the given operand is known to be less + -- than 4. Returns False if this length is known to be four or greater + -- or is not known at compile time. + + ------------------------ + -- Length_Less_Than_4 -- + ------------------------ + + function Length_Less_Than_4 (Opnd : Node_Id) return Boolean is + Otyp : constant Entity_Id := Etype (Opnd); + + begin + if Ekind (Otyp) = E_String_Literal_Subtype then + return String_Literal_Length (Otyp) < 4; + + else + declare + Ityp : constant Entity_Id := Etype (First_Index (Otyp)); + Lo : constant Node_Id := Type_Low_Bound (Ityp); + Hi : constant Node_Id := Type_High_Bound (Ityp); + Lov : Uint; + Hiv : Uint; + + begin + if Compile_Time_Known_Value (Lo) then + Lov := Expr_Value (Lo); + else + return False; + end if; + + if Compile_Time_Known_Value (Hi) then + Hiv := Expr_Value (Hi); + else + return False; + end if; + + return Hiv < Lov + 3; + end; + end if; + end Length_Less_Than_4; + + -- Start of processing for Expand_Array_Comparison + + begin + -- Deal first with unpacked case, where we can call a runtime routine + -- except that we avoid this for targets for which are not addressable + -- by bytes. + + if not Is_Bit_Packed_Array (Typ1) + and then Byte_Addressable + then + -- The call we generate is: + + -- Compare_Array_xn[_Unaligned] + -- (left'address, right'address, left'length, right'length) <op> 0 + + -- x = U for unsigned, S for signed + -- n = 8,16,32,64 for component size + -- Add _Unaligned if length < 4 and component size is 8. + -- <op> is the standard comparison operator + + if Component_Size (Typ1) = 8 then + if Length_Less_Than_4 (Op1) + or else + Length_Less_Than_4 (Op2) + then + if Is_Unsigned_Type (Ctyp) then + Comp := RE_Compare_Array_U8_Unaligned; + else + Comp := RE_Compare_Array_S8_Unaligned; + end if; + + else + if Is_Unsigned_Type (Ctyp) then + Comp := RE_Compare_Array_U8; + else + Comp := RE_Compare_Array_S8; + end if; + end if; + + elsif Component_Size (Typ1) = 16 then + if Is_Unsigned_Type (Ctyp) then + Comp := RE_Compare_Array_U16; + else + Comp := RE_Compare_Array_S16; + end if; + + elsif Component_Size (Typ1) = 32 then + if Is_Unsigned_Type (Ctyp) then + Comp := RE_Compare_Array_U32; + else + Comp := RE_Compare_Array_S32; + end if; + + else pragma Assert (Component_Size (Typ1) = 64); + if Is_Unsigned_Type (Ctyp) then + Comp := RE_Compare_Array_U64; + else + Comp := RE_Compare_Array_S64; + end if; + end if; + + if RTE_Available (Comp) then + + -- Expand to a call only if the runtime function is available, + -- otherwise fall back to inline code. + + Remove_Side_Effects (Op1, Name_Req => True); + Remove_Side_Effects (Op2, Name_Req => True); + + Rewrite (Op1, + Make_Function_Call (Sloc (Op1), + Name => New_Occurrence_Of (RTE (Comp), Loc), + + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Op1), + Attribute_Name => Name_Address), + + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Op2), + Attribute_Name => Name_Address), + + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Op1), + Attribute_Name => Name_Length), + + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Op2), + Attribute_Name => Name_Length)))); + + Rewrite (Op2, + Make_Integer_Literal (Sloc (Op2), + Intval => Uint_0)); + + Analyze_And_Resolve (Op1, Standard_Integer); + Analyze_And_Resolve (Op2, Standard_Integer); + return; + end if; + end if; + + -- Cases where we cannot make runtime call + + -- For (a <= b) we convert to not (a > b) + + if Chars (N) = Name_Op_Le then + Rewrite (N, + Make_Op_Not (Loc, + Right_Opnd => + Make_Op_Gt (Loc, + Left_Opnd => Op1, + Right_Opnd => Op2))); + Analyze_And_Resolve (N, Standard_Boolean); + return; + + -- For < the Boolean expression is + -- greater__nn (op2, op1) + + elsif Chars (N) = Name_Op_Lt then + Func_Body := Make_Array_Comparison_Op (Typ1, N); + + -- Switch operands + + Op1 := Right_Opnd (N); + Op2 := Left_Opnd (N); + + -- For (a >= b) we convert to not (a < b) + + elsif Chars (N) = Name_Op_Ge then + Rewrite (N, + Make_Op_Not (Loc, + Right_Opnd => + Make_Op_Lt (Loc, + Left_Opnd => Op1, + Right_Opnd => Op2))); + Analyze_And_Resolve (N, Standard_Boolean); + return; + + -- For > the Boolean expression is + -- greater__nn (op1, op2) + + else + pragma Assert (Chars (N) = Name_Op_Gt); + Func_Body := Make_Array_Comparison_Op (Typ1, N); + end if; + + Func_Name := Defining_Unit_Name (Specification (Func_Body)); + Expr := + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Func_Name, Loc), + Parameter_Associations => New_List (Op1, Op2)); + + Insert_Action (N, Func_Body); + Rewrite (N, Expr); + Analyze_And_Resolve (N, Standard_Boolean); + end Expand_Array_Comparison; + + --------------------------- + -- Expand_Array_Equality -- + --------------------------- + + -- Expand an equality function for multi-dimensional arrays. Here is an + -- example of such a function for Nb_Dimension = 2 + + -- function Enn (A : atyp; B : btyp) return boolean is + -- begin + -- if (A'length (1) = 0 or else A'length (2) = 0) + -- and then + -- (B'length (1) = 0 or else B'length (2) = 0) + -- then + -- return True; -- RM 4.5.2(22) + -- end if; + + -- if A'length (1) /= B'length (1) + -- or else + -- A'length (2) /= B'length (2) + -- then + -- return False; -- RM 4.5.2(23) + -- end if; + + -- declare + -- A1 : Index_T1 := A'first (1); + -- B1 : Index_T1 := B'first (1); + -- begin + -- loop + -- declare + -- A2 : Index_T2 := A'first (2); + -- B2 : Index_T2 := B'first (2); + -- begin + -- loop + -- if A (A1, A2) /= B (B1, B2) then + -- return False; + -- end if; + + -- exit when A2 = A'last (2); + -- A2 := Index_T2'succ (A2); + -- B2 := Index_T2'succ (B2); + -- end loop; + -- end; + + -- exit when A1 = A'last (1); + -- A1 := Index_T1'succ (A1); + -- B1 := Index_T1'succ (B1); + -- end loop; + -- end; + + -- return true; + -- end Enn; + + -- Note on the formal types used (atyp and btyp). If either of the arrays + -- is of a private type, we use the underlying type, and do an unchecked + -- conversion of the actual. If either of the arrays has a bound depending + -- on a discriminant, then we use the base type since otherwise we have an + -- escaped discriminant in the function. + + -- If both arrays are constrained and have the same bounds, we can generate + -- a loop with an explicit iteration scheme using a 'Range attribute over + -- the first array. + + function Expand_Array_Equality + (Nod : Node_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Bodies : List_Id; + Typ : Entity_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (Nod); + Decls : constant List_Id := New_List; + Index_List1 : constant List_Id := New_List; + Index_List2 : constant List_Id := New_List; + + Actuals : List_Id; + Formals : List_Id; + Func_Name : Entity_Id; + Func_Body : Node_Id; + + A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); + B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); + + Ltyp : Entity_Id; + Rtyp : Entity_Id; + -- The parameter types to be used for the formals + + function Arr_Attr + (Arr : Entity_Id; + Nam : Name_Id; + Num : Int) return Node_Id; + -- This builds the attribute reference Arr'Nam (Expr) + + function Component_Equality (Typ : Entity_Id) return Node_Id; + -- Create one statement to compare corresponding components, designated + -- by a full set of indexes. + + function Get_Arg_Type (N : Node_Id) return Entity_Id; + -- Given one of the arguments, computes the appropriate type to be used + -- for that argument in the corresponding function formal + + function Handle_One_Dimension + (N : Int; + Index : Node_Id) return Node_Id; + -- This procedure returns the following code + -- + -- declare + -- Bn : Index_T := B'First (N); + -- begin + -- loop + -- xxx + -- exit when An = A'Last (N); + -- An := Index_T'Succ (An) + -- Bn := Index_T'Succ (Bn) + -- end loop; + -- end; + -- + -- If both indexes are constrained and identical, the procedure + -- returns a simpler loop: + -- + -- for An in A'Range (N) loop + -- xxx + -- end loop + -- + -- N is the dimension for which we are generating a loop. Index is the + -- N'th index node, whose Etype is Index_Type_n in the above code. The + -- xxx statement is either the loop or declare for the next dimension + -- or if this is the last dimension the comparison of corresponding + -- components of the arrays. + -- + -- The actual way the code works is to return the comparison of + -- corresponding components for the N+1 call. That's neater. + + function Test_Empty_Arrays return Node_Id; + -- This function constructs the test for both arrays being empty + -- (A'length (1) = 0 or else A'length (2) = 0 or else ...) + -- and then + -- (B'length (1) = 0 or else B'length (2) = 0 or else ...) + + function Test_Lengths_Correspond return Node_Id; + -- This function constructs the test for arrays having different lengths + -- in at least one index position, in which case the resulting code is: + + -- A'length (1) /= B'length (1) + -- or else + -- A'length (2) /= B'length (2) + -- or else + -- ... + + -------------- + -- Arr_Attr -- + -------------- + + function Arr_Attr + (Arr : Entity_Id; + Nam : Name_Id; + Num : Int) return Node_Id + is + begin + return + Make_Attribute_Reference (Loc, + Attribute_Name => Nam, + Prefix => New_Occurrence_Of (Arr, Loc), + Expressions => New_List (Make_Integer_Literal (Loc, Num))); + end Arr_Attr; + + ------------------------ + -- Component_Equality -- + ------------------------ + + function Component_Equality (Typ : Entity_Id) return Node_Id is + Test : Node_Id; + L, R : Node_Id; + + begin + -- if a(i1...) /= b(j1...) then return false; end if; + + L := + Make_Indexed_Component (Loc, + Prefix => Make_Identifier (Loc, Chars (A)), + Expressions => Index_List1); + + R := + Make_Indexed_Component (Loc, + Prefix => Make_Identifier (Loc, Chars (B)), + Expressions => Index_List2); + + Test := Expand_Composite_Equality + (Nod, Component_Type (Typ), L, R, Decls); + + -- If some (sub)component is an unchecked_union, the whole operation + -- will raise program error. + + if Nkind (Test) = N_Raise_Program_Error then + + -- This node is going to be inserted at a location where a + -- statement is expected: clear its Etype so analysis will set + -- it to the expected Standard_Void_Type. + + Set_Etype (Test, Empty); + return Test; + + else + return + Make_Implicit_If_Statement (Nod, + Condition => Make_Op_Not (Loc, Right_Opnd => Test), + Then_Statements => New_List ( + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Standard_False, Loc)))); + end if; + end Component_Equality; + + ------------------ + -- Get_Arg_Type -- + ------------------ + + function Get_Arg_Type (N : Node_Id) return Entity_Id is + T : Entity_Id; + X : Node_Id; + + begin + T := Etype (N); + + if No (T) then + return Typ; + + else + T := Underlying_Type (T); + + X := First_Index (T); + while Present (X) loop + if Denotes_Discriminant (Type_Low_Bound (Etype (X))) + or else + Denotes_Discriminant (Type_High_Bound (Etype (X))) + then + T := Base_Type (T); + exit; + end if; + + Next_Index (X); + end loop; + + return T; + end if; + end Get_Arg_Type; + + -------------------------- + -- Handle_One_Dimension -- + --------------------------- + + function Handle_One_Dimension + (N : Int; + Index : Node_Id) return Node_Id + is + Need_Separate_Indexes : constant Boolean := + Ltyp /= Rtyp or else not Is_Constrained (Ltyp); + -- If the index types are identical, and we are working with + -- constrained types, then we can use the same index for both + -- of the arrays. + + An : constant Entity_Id := Make_Temporary (Loc, 'A'); + + Bn : Entity_Id; + Index_T : Entity_Id; + Stm_List : List_Id; + Loop_Stm : Node_Id; + + begin + if N > Number_Dimensions (Ltyp) then + return Component_Equality (Ltyp); + end if; + + -- Case where we generate a loop + + Index_T := Base_Type (Etype (Index)); + + if Need_Separate_Indexes then + Bn := Make_Temporary (Loc, 'B'); + else + Bn := An; + end if; + + Append (New_Occurrence_Of (An, Loc), Index_List1); + Append (New_Occurrence_Of (Bn, Loc), Index_List2); + + Stm_List := New_List ( + Handle_One_Dimension (N + 1, Next_Index (Index))); + + if Need_Separate_Indexes then + + -- Generate guard for loop, followed by increments of indexes + + Append_To (Stm_List, + Make_Exit_Statement (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (An, Loc), + Right_Opnd => Arr_Attr (A, Name_Last, N)))); + + Append_To (Stm_List, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (An, Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Index_T, Loc), + Attribute_Name => Name_Succ, + Expressions => New_List ( + New_Occurrence_Of (An, Loc))))); + + Append_To (Stm_List, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Bn, Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Index_T, Loc), + Attribute_Name => Name_Succ, + Expressions => New_List ( + New_Occurrence_Of (Bn, Loc))))); + end if; + + -- If separate indexes, we need a declare block for An and Bn, and a + -- loop without an iteration scheme. + + if Need_Separate_Indexes then + Loop_Stm := + Make_Implicit_Loop_Statement (Nod, Statements => Stm_List); + + return + Make_Block_Statement (Loc, + Declarations => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => An, + Object_Definition => New_Occurrence_Of (Index_T, Loc), + Expression => Arr_Attr (A, Name_First, N)), + + Make_Object_Declaration (Loc, + Defining_Identifier => Bn, + Object_Definition => New_Occurrence_Of (Index_T, Loc), + Expression => Arr_Attr (B, Name_First, N))), + + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Loop_Stm))); + + -- If no separate indexes, return loop statement with explicit + -- iteration scheme on its own + + else + Loop_Stm := + Make_Implicit_Loop_Statement (Nod, + Statements => Stm_List, + Iteration_Scheme => + Make_Iteration_Scheme (Loc, + Loop_Parameter_Specification => + Make_Loop_Parameter_Specification (Loc, + Defining_Identifier => An, + Discrete_Subtype_Definition => + Arr_Attr (A, Name_Range, N)))); + return Loop_Stm; + end if; + end Handle_One_Dimension; + + ----------------------- + -- Test_Empty_Arrays -- + ----------------------- + + function Test_Empty_Arrays return Node_Id is + Alist : Node_Id; + Blist : Node_Id; + + Atest : Node_Id; + Btest : Node_Id; + + begin + Alist := Empty; + Blist := Empty; + for J in 1 .. Number_Dimensions (Ltyp) loop + Atest := + Make_Op_Eq (Loc, + Left_Opnd => Arr_Attr (A, Name_Length, J), + Right_Opnd => Make_Integer_Literal (Loc, 0)); + + Btest := + Make_Op_Eq (Loc, + Left_Opnd => Arr_Attr (B, Name_Length, J), + Right_Opnd => Make_Integer_Literal (Loc, 0)); + + if No (Alist) then + Alist := Atest; + Blist := Btest; + + else + Alist := + Make_Or_Else (Loc, + Left_Opnd => Relocate_Node (Alist), + Right_Opnd => Atest); + + Blist := + Make_Or_Else (Loc, + Left_Opnd => Relocate_Node (Blist), + Right_Opnd => Btest); + end if; + end loop; + + return + Make_And_Then (Loc, + Left_Opnd => Alist, + Right_Opnd => Blist); + end Test_Empty_Arrays; + + ----------------------------- + -- Test_Lengths_Correspond -- + ----------------------------- + + function Test_Lengths_Correspond return Node_Id is + Result : Node_Id; + Rtest : Node_Id; + + begin + Result := Empty; + for J in 1 .. Number_Dimensions (Ltyp) loop + Rtest := + Make_Op_Ne (Loc, + Left_Opnd => Arr_Attr (A, Name_Length, J), + Right_Opnd => Arr_Attr (B, Name_Length, J)); + + if No (Result) then + Result := Rtest; + else + Result := + Make_Or_Else (Loc, + Left_Opnd => Relocate_Node (Result), + Right_Opnd => Rtest); + end if; + end loop; + + return Result; + end Test_Lengths_Correspond; + + -- Start of processing for Expand_Array_Equality + + begin + Ltyp := Get_Arg_Type (Lhs); + Rtyp := Get_Arg_Type (Rhs); + + -- For now, if the argument types are not the same, go to the base type, + -- since the code assumes that the formals have the same type. This is + -- fixable in future ??? + + if Ltyp /= Rtyp then + Ltyp := Base_Type (Ltyp); + Rtyp := Base_Type (Rtyp); + pragma Assert (Ltyp = Rtyp); + end if; + + -- Build list of formals for function + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => A, + Parameter_Type => New_Occurrence_Of (Ltyp, Loc)), + + Make_Parameter_Specification (Loc, + Defining_Identifier => B, + Parameter_Type => New_Occurrence_Of (Rtyp, Loc))); + + Func_Name := Make_Temporary (Loc, 'E'); + + -- Build statement sequence for function + + Func_Body := + Make_Subprogram_Body (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Func_Name, + Parameter_Specifications => Formals, + Result_Definition => New_Occurrence_Of (Standard_Boolean, Loc)), + + Declarations => Decls, + + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + + Make_Implicit_If_Statement (Nod, + Condition => Test_Empty_Arrays, + Then_Statements => New_List ( + Make_Simple_Return_Statement (Loc, + Expression => + New_Occurrence_Of (Standard_True, Loc)))), + + Make_Implicit_If_Statement (Nod, + Condition => Test_Lengths_Correspond, + Then_Statements => New_List ( + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Standard_False, Loc)))), + + Handle_One_Dimension (1, First_Index (Ltyp)), + + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Standard_True, Loc))))); + + Set_Has_Completion (Func_Name, True); + Set_Is_Inlined (Func_Name); + + -- If the array type is distinct from the type of the arguments, it + -- is the full view of a private type. Apply an unchecked conversion + -- to insure that analysis of the call succeeds. + + declare + L, R : Node_Id; + + begin + L := Lhs; + R := Rhs; + + if No (Etype (Lhs)) + or else Base_Type (Etype (Lhs)) /= Base_Type (Ltyp) + then + L := OK_Convert_To (Ltyp, Lhs); + end if; + + if No (Etype (Rhs)) + or else Base_Type (Etype (Rhs)) /= Base_Type (Rtyp) + then + R := OK_Convert_To (Rtyp, Rhs); + end if; + + Actuals := New_List (L, R); + end; + + Append_To (Bodies, Func_Body); + + return + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Func_Name, Loc), + Parameter_Associations => Actuals); + end Expand_Array_Equality; + + ----------------------------- + -- Expand_Boolean_Operator -- + ----------------------------- + + -- Note that we first get the actual subtypes of the operands, since we + -- always want to deal with types that have bounds. + + procedure Expand_Boolean_Operator (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + -- Special case of bit packed array where both operands are known to be + -- properly aligned. In this case we use an efficient run time routine + -- to carry out the operation (see System.Bit_Ops). + + if Is_Bit_Packed_Array (Typ) + and then not Is_Possibly_Unaligned_Object (Left_Opnd (N)) + and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) + then + Expand_Packed_Boolean_Operator (N); + return; + end if; + + -- For the normal non-packed case, the general expansion is to build + -- function for carrying out the comparison (use Make_Boolean_Array_Op) + -- and then inserting it into the tree. The original operator node is + -- then rewritten as a call to this function. We also use this in the + -- packed case if either operand is a possibly unaligned object. + + declare + Loc : constant Source_Ptr := Sloc (N); + L : constant Node_Id := Relocate_Node (Left_Opnd (N)); + R : constant Node_Id := Relocate_Node (Right_Opnd (N)); + Func_Body : Node_Id; + Func_Name : Entity_Id; + + begin + Convert_To_Actual_Subtype (L); + Convert_To_Actual_Subtype (R); + Ensure_Defined (Etype (L), N); + Ensure_Defined (Etype (R), N); + Apply_Length_Check (R, Etype (L)); + + if Nkind (N) = N_Op_Xor then + Silly_Boolean_Array_Xor_Test (N, Etype (L)); + end if; + + if Nkind (Parent (N)) = N_Assignment_Statement + and then Safe_In_Place_Array_Op (Name (Parent (N)), L, R) + then + Build_Boolean_Array_Proc_Call (Parent (N), L, R); + + elsif Nkind (Parent (N)) = N_Op_Not + and then Nkind (N) = N_Op_And + and then Nkind (Parent (Parent (N))) = N_Assignment_Statement + and then Safe_In_Place_Array_Op (Name (Parent (Parent (N))), L, R) + then + return; + else + + Func_Body := Make_Boolean_Array_Op (Etype (L), N); + Func_Name := Defining_Unit_Name (Specification (Func_Body)); + Insert_Action (N, Func_Body); + + -- Now rewrite the expression with a call + + Rewrite (N, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Func_Name, Loc), + Parameter_Associations => + New_List ( + L, + Make_Type_Conversion + (Loc, New_Occurrence_Of (Etype (L), Loc), R)))); + + Analyze_And_Resolve (N, Typ); + end if; + end; + end Expand_Boolean_Operator; + + ------------------------------------------------ + -- Expand_Compare_Minimize_Eliminate_Overflow -- + ------------------------------------------------ + + procedure Expand_Compare_Minimize_Eliminate_Overflow (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + + Result_Type : constant Entity_Id := Etype (N); + -- Capture result type (could be a derived boolean type) + + Llo, Lhi : Uint; + Rlo, Rhi : Uint; + + LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); + -- Entity for Long_Long_Integer'Base + + Check : constant Overflow_Mode_Type := Overflow_Check_Mode; + -- Current overflow checking mode + + procedure Set_True; + procedure Set_False; + -- These procedures rewrite N with an occurrence of Standard_True or + -- Standard_False, and then makes a call to Warn_On_Known_Condition. + + --------------- + -- Set_False -- + --------------- + + procedure Set_False is + begin + Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); + Warn_On_Known_Condition (N); + end Set_False; + + -------------- + -- Set_True -- + -------------- + + procedure Set_True is + begin + Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); + Warn_On_Known_Condition (N); + end Set_True; + + -- Start of processing for Expand_Compare_Minimize_Eliminate_Overflow + + begin + -- Nothing to do unless we have a comparison operator with operands + -- that are signed integer types, and we are operating in either + -- MINIMIZED or ELIMINATED overflow checking mode. + + if Nkind (N) not in N_Op_Compare + or else Check not in Minimized_Or_Eliminated + or else not Is_Signed_Integer_Type (Etype (Left_Opnd (N))) + then + return; + end if; + + -- OK, this is the case we are interested in. First step is to process + -- our operands using the Minimize_Eliminate circuitry which applies + -- this processing to the two operand subtrees. + + Minimize_Eliminate_Overflows + (Left_Opnd (N), Llo, Lhi, Top_Level => False); + Minimize_Eliminate_Overflows + (Right_Opnd (N), Rlo, Rhi, Top_Level => False); + + -- See if the range information decides the result of the comparison. + -- We can only do this if we in fact have full range information (which + -- won't be the case if either operand is bignum at this stage). + + if Llo /= No_Uint and then Rlo /= No_Uint then + case N_Op_Compare (Nkind (N)) is + when N_Op_Eq => + if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then + Set_True; + elsif Llo > Rhi or else Lhi < Rlo then + Set_False; + end if; + + when N_Op_Ge => + if Llo >= Rhi then + Set_True; + elsif Lhi < Rlo then + Set_False; + end if; + + when N_Op_Gt => + if Llo > Rhi then + Set_True; + elsif Lhi <= Rlo then + Set_False; + end if; + + when N_Op_Le => + if Llo > Rhi then + Set_False; + elsif Lhi <= Rlo then + Set_True; + end if; + + when N_Op_Lt => + if Llo >= Rhi then + Set_False; + elsif Lhi < Rlo then + Set_True; + end if; + + when N_Op_Ne => + if Llo = Lhi and then Rlo = Rhi and then Llo = Rlo then + Set_False; + elsif Llo > Rhi or else Lhi < Rlo then + Set_True; + end if; + end case; + + -- All done if we did the rewrite + + if Nkind (N) not in N_Op_Compare then + return; + end if; + end if; + + -- Otherwise, time to do the comparison + + declare + Ltype : constant Entity_Id := Etype (Left_Opnd (N)); + Rtype : constant Entity_Id := Etype (Right_Opnd (N)); + + begin + -- If the two operands have the same signed integer type we are + -- all set, nothing more to do. This is the case where either + -- both operands were unchanged, or we rewrote both of them to + -- be Long_Long_Integer. + + -- Note: Entity for the comparison may be wrong, but it's not worth + -- the effort to change it, since the back end does not use it. + + if Is_Signed_Integer_Type (Ltype) + and then Base_Type (Ltype) = Base_Type (Rtype) + then + return; + + -- Here if bignums are involved (can only happen in ELIMINATED mode) + + elsif Is_RTE (Ltype, RE_Bignum) or else Is_RTE (Rtype, RE_Bignum) then + declare + Left : Node_Id := Left_Opnd (N); + Right : Node_Id := Right_Opnd (N); + -- Bignum references for left and right operands + + begin + if not Is_RTE (Ltype, RE_Bignum) then + Left := Convert_To_Bignum (Left); + elsif not Is_RTE (Rtype, RE_Bignum) then + Right := Convert_To_Bignum (Right); + end if; + + -- We rewrite our node with: + + -- do + -- Bnn : Result_Type; + -- declare + -- M : Mark_Id := SS_Mark; + -- begin + -- Bnn := Big_xx (Left, Right); (xx = EQ, NT etc) + -- SS_Release (M); + -- end; + -- in + -- Bnn + -- end + + declare + Blk : constant Node_Id := Make_Bignum_Block (Loc); + Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); + Ent : RE_Id; + + begin + case N_Op_Compare (Nkind (N)) is + when N_Op_Eq => Ent := RE_Big_EQ; + when N_Op_Ge => Ent := RE_Big_GE; + when N_Op_Gt => Ent := RE_Big_GT; + when N_Op_Le => Ent := RE_Big_LE; + when N_Op_Lt => Ent := RE_Big_LT; + when N_Op_Ne => Ent := RE_Big_NE; + end case; + + -- Insert assignment to Bnn into the bignum block + + Insert_Before + (First (Statements (Handled_Statement_Sequence (Blk))), + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Bnn, Loc), + Expression => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (Ent), Loc), + Parameter_Associations => New_List (Left, Right)))); + + -- Now do the rewrite with expression actions + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Actions => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Bnn, + Object_Definition => + New_Occurrence_Of (Result_Type, Loc)), + Blk), + Expression => New_Occurrence_Of (Bnn, Loc))); + Analyze_And_Resolve (N, Result_Type); + end; + end; + + -- No bignums involved, but types are different, so we must have + -- rewritten one of the operands as a Long_Long_Integer but not + -- the other one. + + -- If left operand is Long_Long_Integer, convert right operand + -- and we are done (with a comparison of two Long_Long_Integers). + + elsif Ltype = LLIB then + Convert_To_And_Rewrite (LLIB, Right_Opnd (N)); + Analyze_And_Resolve (Right_Opnd (N), LLIB, Suppress => All_Checks); + return; + + -- If right operand is Long_Long_Integer, convert left operand + -- and we are done (with a comparison of two Long_Long_Integers). + + -- This is the only remaining possibility + + else pragma Assert (Rtype = LLIB); + Convert_To_And_Rewrite (LLIB, Left_Opnd (N)); + Analyze_And_Resolve (Left_Opnd (N), LLIB, Suppress => All_Checks); + return; + end if; + end; + end Expand_Compare_Minimize_Eliminate_Overflow; + + ------------------------------- + -- Expand_Composite_Equality -- + ------------------------------- + + -- This function is only called for comparing internal fields of composite + -- types when these fields are themselves composites. This is a special + -- case because it is not possible to respect normal Ada visibility rules. + + function Expand_Composite_Equality + (Nod : Node_Id; + Typ : Entity_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Bodies : List_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (Nod); + Full_Type : Entity_Id; + Prim : Elmt_Id; + Eq_Op : Entity_Id; + + function Find_Primitive_Eq return Node_Id; + -- AI05-0123: Locate primitive equality for type if it exists, and + -- build the corresponding call. If operation is abstract, replace + -- call with an explicit raise. Return Empty if there is no primitive. + + ----------------------- + -- Find_Primitive_Eq -- + ----------------------- + + function Find_Primitive_Eq return Node_Id is + Prim_E : Elmt_Id; + Prim : Node_Id; + + begin + Prim_E := First_Elmt (Collect_Primitive_Operations (Typ)); + while Present (Prim_E) loop + Prim := Node (Prim_E); + + -- Locate primitive equality with the right signature + + if Chars (Prim) = Name_Op_Eq + and then Etype (First_Formal (Prim)) = + Etype (Next_Formal (First_Formal (Prim))) + and then Etype (Prim) = Standard_Boolean + then + if Is_Abstract_Subprogram (Prim) then + return + Make_Raise_Program_Error (Loc, + Reason => PE_Explicit_Raise); + + else + return + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Prim, Loc), + Parameter_Associations => New_List (Lhs, Rhs)); + end if; + end if; + + Next_Elmt (Prim_E); + end loop; + + -- If not found, predefined operation will be used + + return Empty; + end Find_Primitive_Eq; + + -- Start of processing for Expand_Composite_Equality + + begin + if Is_Private_Type (Typ) then + Full_Type := Underlying_Type (Typ); + else + Full_Type := Typ; + end if; + + -- If the private type has no completion the context may be the + -- expansion of a composite equality for a composite type with some + -- still incomplete components. The expression will not be analyzed + -- until the enclosing type is completed, at which point this will be + -- properly expanded, unless there is a bona fide completion error. + + if No (Full_Type) then + return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); + end if; + + Full_Type := Base_Type (Full_Type); + + -- When the base type itself is private, use the full view to expand + -- the composite equality. + + if Is_Private_Type (Full_Type) then + Full_Type := Underlying_Type (Full_Type); + end if; + + -- Case of array types + + if Is_Array_Type (Full_Type) then + + -- If the operand is an elementary type other than a floating-point + -- type, then we can simply use the built-in block bitwise equality, + -- since the predefined equality operators always apply and bitwise + -- equality is fine for all these cases. + + if Is_Elementary_Type (Component_Type (Full_Type)) + and then not Is_Floating_Point_Type (Component_Type (Full_Type)) + then + return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); + + -- For composite component types, and floating-point types, use the + -- expansion. This deals with tagged component types (where we use + -- the applicable equality routine) and floating-point, (where we + -- need to worry about negative zeroes), and also the case of any + -- composite type recursively containing such fields. + + else + return Expand_Array_Equality (Nod, Lhs, Rhs, Bodies, Full_Type); + end if; + + -- Case of tagged record types + + elsif Is_Tagged_Type (Full_Type) then + + -- Call the primitive operation "=" of this type + + if Is_Class_Wide_Type (Full_Type) then + Full_Type := Root_Type (Full_Type); + end if; + + -- If this is derived from an untagged private type completed with a + -- tagged type, it does not have a full view, so we use the primitive + -- operations of the private type. This check should no longer be + -- necessary when these types receive their full views ??? + + if Is_Private_Type (Typ) + and then not Is_Tagged_Type (Typ) + and then not Is_Controlled (Typ) + and then Is_Derived_Type (Typ) + and then No (Full_View (Typ)) + then + Prim := First_Elmt (Collect_Primitive_Operations (Typ)); + else + Prim := First_Elmt (Primitive_Operations (Full_Type)); + end if; + + loop + Eq_Op := Node (Prim); + exit when Chars (Eq_Op) = Name_Op_Eq + and then Etype (First_Formal (Eq_Op)) = + Etype (Next_Formal (First_Formal (Eq_Op))) + and then Base_Type (Etype (Eq_Op)) = Standard_Boolean; + Next_Elmt (Prim); + pragma Assert (Present (Prim)); + end loop; + + Eq_Op := Node (Prim); + + return + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Eq_Op, Loc), + Parameter_Associations => + New_List + (Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Lhs), + Unchecked_Convert_To (Etype (First_Formal (Eq_Op)), Rhs))); + + -- Case of untagged record types + + elsif Is_Record_Type (Full_Type) then + Eq_Op := TSS (Full_Type, TSS_Composite_Equality); + + if Present (Eq_Op) then + if Etype (First_Formal (Eq_Op)) /= Full_Type then + + -- Inherited equality from parent type. Convert the actuals to + -- match signature of operation. + + declare + T : constant Entity_Id := Etype (First_Formal (Eq_Op)); + + begin + return + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Eq_Op, Loc), + Parameter_Associations => New_List ( + OK_Convert_To (T, Lhs), + OK_Convert_To (T, Rhs))); + end; + + else + -- Comparison between Unchecked_Union components + + if Is_Unchecked_Union (Full_Type) then + declare + Lhs_Type : Node_Id := Full_Type; + Rhs_Type : Node_Id := Full_Type; + Lhs_Discr_Val : Node_Id; + Rhs_Discr_Val : Node_Id; + + begin + -- Lhs subtype + + if Nkind (Lhs) = N_Selected_Component then + Lhs_Type := Etype (Entity (Selector_Name (Lhs))); + end if; + + -- Rhs subtype + + if Nkind (Rhs) = N_Selected_Component then + Rhs_Type := Etype (Entity (Selector_Name (Rhs))); + end if; + + -- Lhs of the composite equality + + if Is_Constrained (Lhs_Type) then + + -- Since the enclosing record type can never be an + -- Unchecked_Union (this code is executed for records + -- that do not have variants), we may reference its + -- discriminant(s). + + if Nkind (Lhs) = N_Selected_Component + and then Has_Per_Object_Constraint + (Entity (Selector_Name (Lhs))) + then + Lhs_Discr_Val := + Make_Selected_Component (Loc, + Prefix => Prefix (Lhs), + Selector_Name => + New_Copy + (Get_Discriminant_Value + (First_Discriminant (Lhs_Type), + Lhs_Type, + Stored_Constraint (Lhs_Type)))); + + else + Lhs_Discr_Val := + New_Copy + (Get_Discriminant_Value + (First_Discriminant (Lhs_Type), + Lhs_Type, + Stored_Constraint (Lhs_Type))); + + end if; + else + -- It is not possible to infer the discriminant since + -- the subtype is not constrained. + + return + Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction); + end if; + + -- Rhs of the composite equality + + if Is_Constrained (Rhs_Type) then + if Nkind (Rhs) = N_Selected_Component + and then Has_Per_Object_Constraint + (Entity (Selector_Name (Rhs))) + then + Rhs_Discr_Val := + Make_Selected_Component (Loc, + Prefix => Prefix (Rhs), + Selector_Name => + New_Copy + (Get_Discriminant_Value + (First_Discriminant (Rhs_Type), + Rhs_Type, + Stored_Constraint (Rhs_Type)))); + + else + Rhs_Discr_Val := + New_Copy + (Get_Discriminant_Value + (First_Discriminant (Rhs_Type), + Rhs_Type, + Stored_Constraint (Rhs_Type))); + + end if; + else + return + Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction); + end if; + + -- Call the TSS equality function with the inferred + -- discriminant values. + + return + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Eq_Op, Loc), + Parameter_Associations => New_List ( + Lhs, + Rhs, + Lhs_Discr_Val, + Rhs_Discr_Val)); + end; + + -- All cases other than comparing Unchecked_Union types + + else + declare + T : constant Entity_Id := Etype (First_Formal (Eq_Op)); + begin + return + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (Eq_Op, Loc), + Parameter_Associations => New_List ( + OK_Convert_To (T, Lhs), + OK_Convert_To (T, Rhs))); + end; + end if; + end if; + + -- Equality composes in Ada 2012 for untagged record types. It also + -- composes for bounded strings, because they are part of the + -- predefined environment. We could make it compose for bounded + -- strings by making them tagged, or by making sure all subcomponents + -- are set to the same value, even when not used. Instead, we have + -- this special case in the compiler, because it's more efficient. + + elsif Ada_Version >= Ada_2012 or else Is_Bounded_String (Typ) then + + -- If no TSS has been created for the type, check whether there is + -- a primitive equality declared for it. + + declare + Op : constant Node_Id := Find_Primitive_Eq; + + begin + -- Use user-defined primitive if it exists, otherwise use + -- predefined equality. + + if Present (Op) then + return Op; + else + return Make_Op_Eq (Loc, Lhs, Rhs); + end if; + end; + + else + return Expand_Record_Equality (Nod, Full_Type, Lhs, Rhs, Bodies); + end if; + + -- Non-composite types (always use predefined equality) + + else + return Make_Op_Eq (Loc, Left_Opnd => Lhs, Right_Opnd => Rhs); + end if; + end Expand_Composite_Equality; + + ------------------------ + -- Expand_Concatenate -- + ------------------------ + + procedure Expand_Concatenate (Cnode : Node_Id; Opnds : List_Id) is + Loc : constant Source_Ptr := Sloc (Cnode); + + Atyp : constant Entity_Id := Base_Type (Etype (Cnode)); + -- Result type of concatenation + + Ctyp : constant Entity_Id := Base_Type (Component_Type (Etype (Cnode))); + -- Component type. Elements of this component type can appear as one + -- of the operands of concatenation as well as arrays. + + Istyp : constant Entity_Id := Etype (First_Index (Atyp)); + -- Index subtype + + Ityp : constant Entity_Id := Base_Type (Istyp); + -- Index type. This is the base type of the index subtype, and is used + -- for all computed bounds (which may be out of range of Istyp in the + -- case of null ranges). + + Artyp : Entity_Id; + -- This is the type we use to do arithmetic to compute the bounds and + -- lengths of operands. The choice of this type is a little subtle and + -- is discussed in a separate section at the start of the body code. + + Concatenation_Error : exception; + -- Raised if concatenation is sure to raise a CE + + Result_May_Be_Null : Boolean := True; + -- Reset to False if at least one operand is encountered which is known + -- at compile time to be non-null. Used for handling the special case + -- of setting the high bound to the last operand high bound for a null + -- result, thus ensuring a proper high bound in the super-flat case. + + N : constant Nat := List_Length (Opnds); + -- Number of concatenation operands including possibly null operands + + NN : Nat := 0; + -- Number of operands excluding any known to be null, except that the + -- last operand is always retained, in case it provides the bounds for + -- a null result. + + Opnd : Node_Id := Empty; + -- Current operand being processed in the loop through operands. After + -- this loop is complete, always contains the last operand (which is not + -- the same as Operands (NN), since null operands are skipped). + + -- Arrays describing the operands, only the first NN entries of each + -- array are set (NN < N when we exclude known null operands). + + Is_Fixed_Length : array (1 .. N) of Boolean; + -- True if length of corresponding operand known at compile time + + Operands : array (1 .. N) of Node_Id; + -- Set to the corresponding entry in the Opnds list (but note that null + -- operands are excluded, so not all entries in the list are stored). + + Fixed_Length : array (1 .. N) of Uint; + -- Set to length of operand. Entries in this array are set only if the + -- corresponding entry in Is_Fixed_Length is True. + + Opnd_Low_Bound : array (1 .. N) of Node_Id; + -- Set to lower bound of operand. Either an integer literal in the case + -- where the bound is known at compile time, else actual lower bound. + -- The operand low bound is of type Ityp. + + Var_Length : array (1 .. N) of Entity_Id; + -- Set to an entity of type Natural that contains the length of an + -- operand whose length is not known at compile time. Entries in this + -- array are set only if the corresponding entry in Is_Fixed_Length + -- is False. The entity is of type Artyp. + + Aggr_Length : array (0 .. N) of Node_Id; + -- The J'th entry in an expression node that represents the total length + -- of operands 1 through J. It is either an integer literal node, or a + -- reference to a constant entity with the right value, so it is fine + -- to just do a Copy_Node to get an appropriate copy. The extra zero'th + -- entry always is set to zero. The length is of type Artyp. + + Low_Bound : Node_Id; + -- A tree node representing the low bound of the result (of type Ityp). + -- This is either an integer literal node, or an identifier reference to + -- a constant entity initialized to the appropriate value. + + Last_Opnd_Low_Bound : Node_Id := Empty; + -- A tree node representing the low bound of the last operand. This + -- need only be set if the result could be null. It is used for the + -- special case of setting the right low bound for a null result. + -- This is of type Ityp. + + Last_Opnd_High_Bound : Node_Id := Empty; + -- A tree node representing the high bound of the last operand. This + -- need only be set if the result could be null. It is used for the + -- special case of setting the right high bound for a null result. + -- This is of type Ityp. + + High_Bound : Node_Id; + -- A tree node representing the high bound of the result (of type Ityp) + + Result : Node_Id; + -- Result of the concatenation (of type Ityp) + + Actions : constant List_Id := New_List; + -- Collect actions to be inserted + + Known_Non_Null_Operand_Seen : Boolean; + -- Set True during generation of the assignments of operands into + -- result once an operand known to be non-null has been seen. + + function Library_Level_Target return Boolean; + -- Return True if the concatenation is within the expression of the + -- declaration of a library-level object. + + function Make_Artyp_Literal (Val : Nat) return Node_Id; + -- This function makes an N_Integer_Literal node that is returned in + -- analyzed form with the type set to Artyp. Importantly this literal + -- is not flagged as static, so that if we do computations with it that + -- result in statically detected out of range conditions, we will not + -- generate error messages but instead warning messages. + + function To_Artyp (X : Node_Id) return Node_Id; + -- Given a node of type Ityp, returns the corresponding value of type + -- Artyp. For non-enumeration types, this is a plain integer conversion. + -- For enum types, the Pos of the value is returned. + + function To_Ityp (X : Node_Id) return Node_Id; + -- The inverse function (uses Val in the case of enumeration types) + + -------------------------- + -- Library_Level_Target -- + -------------------------- + + function Library_Level_Target return Boolean is + P : Node_Id := Parent (Cnode); + + begin + while Present (P) loop + if Nkind (P) = N_Object_Declaration then + return Is_Library_Level_Entity (Defining_Identifier (P)); + + -- Prevent the search from going too far + + elsif Is_Body_Or_Package_Declaration (P) then + return False; + end if; + + P := Parent (P); + end loop; + + return False; + end Library_Level_Target; + + ------------------------ + -- Make_Artyp_Literal -- + ------------------------ + + function Make_Artyp_Literal (Val : Nat) return Node_Id is + Result : constant Node_Id := Make_Integer_Literal (Loc, Val); + begin + Set_Etype (Result, Artyp); + Set_Analyzed (Result, True); + Set_Is_Static_Expression (Result, False); + return Result; + end Make_Artyp_Literal; + + -------------- + -- To_Artyp -- + -------------- + + function To_Artyp (X : Node_Id) return Node_Id is + begin + if Ityp = Base_Type (Artyp) then + return X; + + elsif Is_Enumeration_Type (Ityp) then + return + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Ityp, Loc), + Attribute_Name => Name_Pos, + Expressions => New_List (X)); + + else + return Convert_To (Artyp, X); + end if; + end To_Artyp; + + ------------- + -- To_Ityp -- + ------------- + + function To_Ityp (X : Node_Id) return Node_Id is + begin + if Is_Enumeration_Type (Ityp) then + return + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Ityp, Loc), + Attribute_Name => Name_Val, + Expressions => New_List (X)); + + -- Case where we will do a type conversion + + else + if Ityp = Base_Type (Artyp) then + return X; + else + return Convert_To (Ityp, X); + end if; + end if; + end To_Ityp; + + -- Local Declarations + + Opnd_Typ : Entity_Id; + Ent : Entity_Id; + Len : Uint; + J : Nat; + Clen : Node_Id; + Set : Boolean; + + -- Start of processing for Expand_Concatenate + + begin + -- Choose an appropriate computational type + + -- We will be doing calculations of lengths and bounds in this routine + -- and computing one from the other in some cases, e.g. getting the high + -- bound by adding the length-1 to the low bound. + + -- We can't just use the index type, or even its base type for this + -- purpose for two reasons. First it might be an enumeration type which + -- is not suitable for computations of any kind, and second it may + -- simply not have enough range. For example if the index type is + -- -128..+127 then lengths can be up to 256, which is out of range of + -- the type. + + -- For enumeration types, we can simply use Standard_Integer, this is + -- sufficient since the actual number of enumeration literals cannot + -- possibly exceed the range of integer (remember we will be doing the + -- arithmetic with POS values, not representation values). + + if Is_Enumeration_Type (Ityp) then + Artyp := Standard_Integer; + + -- If index type is Positive, we use the standard unsigned type, to give + -- more room on the top of the range, obviating the need for an overflow + -- check when creating the upper bound. This is needed to avoid junk + -- overflow checks in the common case of String types. + + -- ??? Disabled for now + + -- elsif Istyp = Standard_Positive then + -- Artyp := Standard_Unsigned; + + -- For modular types, we use a 32-bit modular type for types whose size + -- is in the range 1-31 bits. For 32-bit unsigned types, we use the + -- identity type, and for larger unsigned types we use 64-bits. + + elsif Is_Modular_Integer_Type (Ityp) then + if RM_Size (Ityp) < RM_Size (Standard_Unsigned) then + Artyp := Standard_Unsigned; + elsif RM_Size (Ityp) = RM_Size (Standard_Unsigned) then + Artyp := Ityp; + else + Artyp := RTE (RE_Long_Long_Unsigned); + end if; + + -- Similar treatment for signed types + + else + if RM_Size (Ityp) < RM_Size (Standard_Integer) then + Artyp := Standard_Integer; + elsif RM_Size (Ityp) = RM_Size (Standard_Integer) then + Artyp := Ityp; + else + Artyp := Standard_Long_Long_Integer; + end if; + end if; + + -- Supply dummy entry at start of length array + + Aggr_Length (0) := Make_Artyp_Literal (0); + + -- Go through operands setting up the above arrays + + J := 1; + while J <= N loop + Opnd := Remove_Head (Opnds); + Opnd_Typ := Etype (Opnd); + + -- The parent got messed up when we put the operands in a list, + -- so now put back the proper parent for the saved operand, that + -- is to say the concatenation node, to make sure that each operand + -- is seen as a subexpression, e.g. if actions must be inserted. + + Set_Parent (Opnd, Cnode); + + -- Set will be True when we have setup one entry in the array + + Set := False; + + -- Singleton element (or character literal) case + + if Base_Type (Opnd_Typ) = Ctyp then + NN := NN + 1; + Operands (NN) := Opnd; + Is_Fixed_Length (NN) := True; + Fixed_Length (NN) := Uint_1; + Result_May_Be_Null := False; + + -- Set low bound of operand (no need to set Last_Opnd_High_Bound + -- since we know that the result cannot be null). + + Opnd_Low_Bound (NN) := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Istyp, Loc), + Attribute_Name => Name_First); + + Set := True; + + -- String literal case (can only occur for strings of course) + + elsif Nkind (Opnd) = N_String_Literal then + Len := String_Literal_Length (Opnd_Typ); + + if Len /= 0 then + Result_May_Be_Null := False; + end if; + + -- Capture last operand low and high bound if result could be null + + if J = N and then Result_May_Be_Null then + Last_Opnd_Low_Bound := + New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); + + Last_Opnd_High_Bound := + Make_Op_Subtract (Loc, + Left_Opnd => + New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)), + Right_Opnd => Make_Integer_Literal (Loc, 1)); + end if; + + -- Skip null string literal + + if J < N and then Len = 0 then + goto Continue; + end if; + + NN := NN + 1; + Operands (NN) := Opnd; + Is_Fixed_Length (NN) := True; + + -- Set length and bounds + + Fixed_Length (NN) := Len; + + Opnd_Low_Bound (NN) := + New_Copy_Tree (String_Literal_Low_Bound (Opnd_Typ)); + + Set := True; + + -- All other cases + + else + -- Check constrained case with known bounds + + if Is_Constrained (Opnd_Typ) then + declare + Index : constant Node_Id := First_Index (Opnd_Typ); + Indx_Typ : constant Entity_Id := Etype (Index); + Lo : constant Node_Id := Type_Low_Bound (Indx_Typ); + Hi : constant Node_Id := Type_High_Bound (Indx_Typ); + + begin + -- Fixed length constrained array type with known at compile + -- time bounds is last case of fixed length operand. + + if Compile_Time_Known_Value (Lo) + and then + Compile_Time_Known_Value (Hi) + then + declare + Loval : constant Uint := Expr_Value (Lo); + Hival : constant Uint := Expr_Value (Hi); + Len : constant Uint := + UI_Max (Hival - Loval + 1, Uint_0); + + begin + if Len > 0 then + Result_May_Be_Null := False; + end if; + + -- Capture last operand bounds if result could be null + + if J = N and then Result_May_Be_Null then + Last_Opnd_Low_Bound := + Convert_To (Ityp, + Make_Integer_Literal (Loc, Expr_Value (Lo))); + + Last_Opnd_High_Bound := + Convert_To (Ityp, + Make_Integer_Literal (Loc, Expr_Value (Hi))); + end if; + + -- Exclude null length case unless last operand + + if J < N and then Len = 0 then + goto Continue; + end if; + + NN := NN + 1; + Operands (NN) := Opnd; + Is_Fixed_Length (NN) := True; + Fixed_Length (NN) := Len; + + Opnd_Low_Bound (NN) := + To_Ityp + (Make_Integer_Literal (Loc, Expr_Value (Lo))); + Set := True; + end; + end if; + end; + end if; + + -- All cases where the length is not known at compile time, or the + -- special case of an operand which is known to be null but has a + -- lower bound other than 1 or is other than a string type. + + if not Set then + NN := NN + 1; + + -- Capture operand bounds + + Opnd_Low_Bound (NN) := + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr (Opnd, Name_Req => True), + Attribute_Name => Name_First); + + -- Capture last operand bounds if result could be null + + if J = N and Result_May_Be_Null then + Last_Opnd_Low_Bound := + Convert_To (Ityp, + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr (Opnd, Name_Req => True), + Attribute_Name => Name_First)); + + Last_Opnd_High_Bound := + Convert_To (Ityp, + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr (Opnd, Name_Req => True), + Attribute_Name => Name_Last)); + end if; + + -- Capture length of operand in entity + + Operands (NN) := Opnd; + Is_Fixed_Length (NN) := False; + + Var_Length (NN) := Make_Temporary (Loc, 'L'); + + Append_To (Actions, + Make_Object_Declaration (Loc, + Defining_Identifier => Var_Length (NN), + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Artyp, Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr (Opnd, Name_Req => True), + Attribute_Name => Name_Length))); + end if; + end if; + + -- Set next entry in aggregate length array + + -- For first entry, make either integer literal for fixed length + -- or a reference to the saved length for variable length. + + if NN = 1 then + if Is_Fixed_Length (1) then + Aggr_Length (1) := Make_Integer_Literal (Loc, Fixed_Length (1)); + else + Aggr_Length (1) := New_Occurrence_Of (Var_Length (1), Loc); + end if; + + -- If entry is fixed length and only fixed lengths so far, make + -- appropriate new integer literal adding new length. + + elsif Is_Fixed_Length (NN) + and then Nkind (Aggr_Length (NN - 1)) = N_Integer_Literal + then + Aggr_Length (NN) := + Make_Integer_Literal (Loc, + Intval => Fixed_Length (NN) + Intval (Aggr_Length (NN - 1))); + + -- All other cases, construct an addition node for the length and + -- create an entity initialized to this length. + + else + Ent := Make_Temporary (Loc, 'L'); + + if Is_Fixed_Length (NN) then + Clen := Make_Integer_Literal (Loc, Fixed_Length (NN)); + else + Clen := New_Occurrence_Of (Var_Length (NN), Loc); + end if; + + Append_To (Actions, + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Artyp, Loc), + Expression => + Make_Op_Add (Loc, + Left_Opnd => New_Copy_Tree (Aggr_Length (NN - 1)), + Right_Opnd => Clen))); + + Aggr_Length (NN) := Make_Identifier (Loc, Chars => Chars (Ent)); + end if; + + <<Continue>> + J := J + 1; + end loop; + + -- If we have only skipped null operands, return the last operand + + if NN = 0 then + Result := Opnd; + goto Done; + end if; + + -- If we have only one non-null operand, return it and we are done. + -- There is one case in which this cannot be done, and that is when + -- the sole operand is of the element type, in which case it must be + -- converted to an array, and the easiest way of doing that is to go + -- through the normal general circuit. + + if NN = 1 and then Base_Type (Etype (Operands (1))) /= Ctyp then + Result := Operands (1); + goto Done; + end if; + + -- Cases where we have a real concatenation + + -- Next step is to find the low bound for the result array that we + -- will allocate. The rules for this are in (RM 4.5.6(5-7)). + + -- If the ultimate ancestor of the index subtype is a constrained array + -- definition, then the lower bound is that of the index subtype as + -- specified by (RM 4.5.3(6)). + + -- The right test here is to go to the root type, and then the ultimate + -- ancestor is the first subtype of this root type. + + if Is_Constrained (First_Subtype (Root_Type (Atyp))) then + Low_Bound := + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (First_Subtype (Root_Type (Atyp)), Loc), + Attribute_Name => Name_First); + + -- If the first operand in the list has known length we know that + -- the lower bound of the result is the lower bound of this operand. + + elsif Is_Fixed_Length (1) then + Low_Bound := Opnd_Low_Bound (1); + + -- OK, we don't know the lower bound, we have to build a horrible + -- if expression node of the form + + -- if Cond1'Length /= 0 then + -- Opnd1 low bound + -- else + -- if Opnd2'Length /= 0 then + -- Opnd2 low bound + -- else + -- ... + + -- The nesting ends either when we hit an operand whose length is known + -- at compile time, or on reaching the last operand, whose low bound we + -- take unconditionally whether or not it is null. It's easiest to do + -- this with a recursive procedure: + + else + declare + function Get_Known_Bound (J : Nat) return Node_Id; + -- Returns the lower bound determined by operands J .. NN + + --------------------- + -- Get_Known_Bound -- + --------------------- + + function Get_Known_Bound (J : Nat) return Node_Id is + begin + if Is_Fixed_Length (J) or else J = NN then + return New_Copy_Tree (Opnd_Low_Bound (J)); + + else + return + Make_If_Expression (Loc, + Expressions => New_List ( + + Make_Op_Ne (Loc, + Left_Opnd => + New_Occurrence_Of (Var_Length (J), Loc), + Right_Opnd => + Make_Integer_Literal (Loc, 0)), + + New_Copy_Tree (Opnd_Low_Bound (J)), + Get_Known_Bound (J + 1))); + end if; + end Get_Known_Bound; + + begin + Ent := Make_Temporary (Loc, 'L'); + + Append_To (Actions, + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Ityp, Loc), + Expression => Get_Known_Bound (1))); + + Low_Bound := New_Occurrence_Of (Ent, Loc); + end; + end if; + + -- Now we can safely compute the upper bound, normally + -- Low_Bound + Length - 1. + + High_Bound := + To_Ityp + (Make_Op_Add (Loc, + Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), + Right_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), + Right_Opnd => Make_Artyp_Literal (1)))); + + -- Note that calculation of the high bound may cause overflow in some + -- very weird cases, so in the general case we need an overflow check on + -- the high bound. We can avoid this for the common case of string types + -- and other types whose index is Positive, since we chose a wider range + -- for the arithmetic type. If checks are suppressed we do not set the + -- flag, and possibly superfluous warnings will be omitted. + + if Istyp /= Standard_Positive + and then not Overflow_Checks_Suppressed (Istyp) + then + Activate_Overflow_Check (High_Bound); + end if; + + -- Handle the exceptional case where the result is null, in which case + -- case the bounds come from the last operand (so that we get the proper + -- bounds if the last operand is super-flat). + + if Result_May_Be_Null then + Low_Bound := + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), + Right_Opnd => Make_Artyp_Literal (0)), + Last_Opnd_Low_Bound, + Low_Bound)); + + High_Bound := + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => New_Copy_Tree (Aggr_Length (NN)), + Right_Opnd => Make_Artyp_Literal (0)), + Last_Opnd_High_Bound, + High_Bound)); + end if; + + -- Here is where we insert the saved up actions + + Insert_Actions (Cnode, Actions, Suppress => All_Checks); + + -- Now we construct an array object with appropriate bounds. We mark + -- the target as internal to prevent useless initialization when + -- Initialize_Scalars is enabled. Also since this is the actual result + -- entity, we make sure we have debug information for the result. + + Ent := Make_Temporary (Loc, 'S'); + Set_Is_Internal (Ent); + Set_Needs_Debug_Info (Ent); + + -- If the bound is statically known to be out of range, we do not want + -- to abort, we want a warning and a runtime constraint error. Note that + -- we have arranged that the result will not be treated as a static + -- constant, so we won't get an illegality during this insertion. + + Insert_Action (Cnode, + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => + Make_Subtype_Indication (Loc, + Subtype_Mark => New_Occurrence_Of (Atyp, Loc), + Constraint => + Make_Index_Or_Discriminant_Constraint (Loc, + Constraints => New_List ( + Make_Range (Loc, + Low_Bound => Low_Bound, + High_Bound => High_Bound))))), + Suppress => All_Checks); + + -- If the result of the concatenation appears as the initializing + -- expression of an object declaration, we can just rename the + -- result, rather than copying it. + + Set_OK_To_Rename (Ent); + + -- Catch the static out of range case now + + if Raises_Constraint_Error (High_Bound) then + raise Concatenation_Error; + end if; + + -- Now we will generate the assignments to do the actual concatenation + + -- There is one case in which we will not do this, namely when all the + -- following conditions are met: + + -- The result type is Standard.String + + -- There are nine or fewer retained (non-null) operands + + -- The optimization level is -O0 or the debug flag gnatd.C is set, + -- and the debug flag gnatd.c is not set. + + -- The corresponding System.Concat_n.Str_Concat_n routine is + -- available in the run time. + + -- If all these conditions are met then we generate a call to the + -- relevant concatenation routine. The purpose of this is to avoid + -- undesirable code bloat at -O0. + + -- If the concatenation is within the declaration of a library-level + -- object, we call the built-in concatenation routines to prevent code + -- bloat, regardless of the optimization level. This is space efficient + -- and prevents linking problems when units are compiled with different + -- optimization levels. + + if Atyp = Standard_String + and then NN in 2 .. 9 + and then (((Optimization_Level = 0 or else Debug_Flag_Dot_CC) + and then not Debug_Flag_Dot_C) + or else Library_Level_Target) + then + declare + RR : constant array (Nat range 2 .. 9) of RE_Id := + (RE_Str_Concat_2, + RE_Str_Concat_3, + RE_Str_Concat_4, + RE_Str_Concat_5, + RE_Str_Concat_6, + RE_Str_Concat_7, + RE_Str_Concat_8, + RE_Str_Concat_9); + + begin + if RTE_Available (RR (NN)) then + declare + Opnds : constant List_Id := + New_List (New_Occurrence_Of (Ent, Loc)); + + begin + for J in 1 .. NN loop + if Is_List_Member (Operands (J)) then + Remove (Operands (J)); + end if; + + if Base_Type (Etype (Operands (J))) = Ctyp then + Append_To (Opnds, + Make_Aggregate (Loc, + Component_Associations => New_List ( + Make_Component_Association (Loc, + Choices => New_List ( + Make_Integer_Literal (Loc, 1)), + Expression => Operands (J))))); + + else + Append_To (Opnds, Operands (J)); + end if; + end loop; + + Insert_Action (Cnode, + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (RTE (RR (NN)), Loc), + Parameter_Associations => Opnds)); + + Result := New_Occurrence_Of (Ent, Loc); + goto Done; + end; + end if; + end; + end if; + + -- Not special case so generate the assignments + + Known_Non_Null_Operand_Seen := False; + + for J in 1 .. NN loop + declare + Lo : constant Node_Id := + Make_Op_Add (Loc, + Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), + Right_Opnd => Aggr_Length (J - 1)); + + Hi : constant Node_Id := + Make_Op_Add (Loc, + Left_Opnd => To_Artyp (New_Copy_Tree (Low_Bound)), + Right_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => Aggr_Length (J), + Right_Opnd => Make_Artyp_Literal (1))); + + begin + -- Singleton case, simple assignment + + if Base_Type (Etype (Operands (J))) = Ctyp then + Known_Non_Null_Operand_Seen := True; + Insert_Action (Cnode, + Make_Assignment_Statement (Loc, + Name => + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (Ent, Loc), + Expressions => New_List (To_Ityp (Lo))), + Expression => Operands (J)), + Suppress => All_Checks); + + -- Array case, slice assignment, skipped when argument is fixed + -- length and known to be null. + + elsif (not Is_Fixed_Length (J)) or else (Fixed_Length (J) > 0) then + declare + Assign : Node_Id := + Make_Assignment_Statement (Loc, + Name => + Make_Slice (Loc, + Prefix => + New_Occurrence_Of (Ent, Loc), + Discrete_Range => + Make_Range (Loc, + Low_Bound => To_Ityp (Lo), + High_Bound => To_Ityp (Hi))), + Expression => Operands (J)); + begin + if Is_Fixed_Length (J) then + Known_Non_Null_Operand_Seen := True; + + elsif not Known_Non_Null_Operand_Seen then + + -- Here if operand length is not statically known and no + -- operand known to be non-null has been processed yet. + -- If operand length is 0, we do not need to perform the + -- assignment, and we must avoid the evaluation of the + -- high bound of the slice, since it may underflow if the + -- low bound is Ityp'First. + + Assign := + Make_Implicit_If_Statement (Cnode, + Condition => + Make_Op_Ne (Loc, + Left_Opnd => + New_Occurrence_Of (Var_Length (J), Loc), + Right_Opnd => Make_Integer_Literal (Loc, 0)), + Then_Statements => New_List (Assign)); + end if; + + Insert_Action (Cnode, Assign, Suppress => All_Checks); + end; + end if; + end; + end loop; + + -- Finally we build the result, which is a reference to the array object + + Result := New_Occurrence_Of (Ent, Loc); + + <<Done>> + Rewrite (Cnode, Result); + Analyze_And_Resolve (Cnode, Atyp); + + exception + when Concatenation_Error => + + -- Kill warning generated for the declaration of the static out of + -- range high bound, and instead generate a Constraint_Error with + -- an appropriate specific message. + + Kill_Dead_Code (Declaration_Node (Entity (High_Bound))); + Apply_Compile_Time_Constraint_Error + (N => Cnode, + Msg => "concatenation result upper bound out of range??", + Reason => CE_Range_Check_Failed); + end Expand_Concatenate; + + --------------------------------------------------- + -- Expand_Membership_Minimize_Eliminate_Overflow -- + --------------------------------------------------- + + procedure Expand_Membership_Minimize_Eliminate_Overflow (N : Node_Id) is + pragma Assert (Nkind (N) = N_In); + -- Despite the name, this routine applies only to N_In, not to + -- N_Not_In. The latter is always rewritten as not (X in Y). + + Result_Type : constant Entity_Id := Etype (N); + -- Capture result type, may be a derived boolean type + + Loc : constant Source_Ptr := Sloc (N); + Lop : constant Node_Id := Left_Opnd (N); + Rop : constant Node_Id := Right_Opnd (N); + + -- Note: there are many referencs to Etype (Lop) and Etype (Rop). It + -- is thus tempting to capture these values, but due to the rewrites + -- that occur as a result of overflow checking, these values change + -- as we go along, and it is safe just to always use Etype explicitly. + + Restype : constant Entity_Id := Etype (N); + -- Save result type + + Lo, Hi : Uint; + -- Bounds in Minimize calls, not used currently + + LLIB : constant Entity_Id := Base_Type (Standard_Long_Long_Integer); + -- Entity for Long_Long_Integer'Base (Standard should export this???) + + begin + Minimize_Eliminate_Overflows (Lop, Lo, Hi, Top_Level => False); + + -- If right operand is a subtype name, and the subtype name has no + -- predicate, then we can just replace the right operand with an + -- explicit range T'First .. T'Last, and use the explicit range code. + + if Nkind (Rop) /= N_Range + and then No (Predicate_Function (Etype (Rop))) + then + declare + Rtyp : constant Entity_Id := Etype (Rop); + begin + Rewrite (Rop, + Make_Range (Loc, + Low_Bound => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_First, + Prefix => New_Occurrence_Of (Rtyp, Loc)), + High_Bound => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Last, + Prefix => New_Occurrence_Of (Rtyp, Loc)))); + Analyze_And_Resolve (Rop, Rtyp, Suppress => All_Checks); + end; + end if; + + -- Here for the explicit range case. Note that the bounds of the range + -- have not been processed for minimized or eliminated checks. + + if Nkind (Rop) = N_Range then + Minimize_Eliminate_Overflows + (Low_Bound (Rop), Lo, Hi, Top_Level => False); + Minimize_Eliminate_Overflows + (High_Bound (Rop), Lo, Hi, Top_Level => False); + + -- We have A in B .. C, treated as A >= B and then A <= C + + -- Bignum case + + if Is_RTE (Etype (Lop), RE_Bignum) + or else Is_RTE (Etype (Low_Bound (Rop)), RE_Bignum) + or else Is_RTE (Etype (High_Bound (Rop)), RE_Bignum) + then + declare + Blk : constant Node_Id := Make_Bignum_Block (Loc); + Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); + L : constant Entity_Id := + Make_Defining_Identifier (Loc, Name_uL); + Lopnd : constant Node_Id := Convert_To_Bignum (Lop); + Lbound : constant Node_Id := + Convert_To_Bignum (Low_Bound (Rop)); + Hbound : constant Node_Id := + Convert_To_Bignum (High_Bound (Rop)); + + -- Now we rewrite the membership test node to look like + + -- do + -- Bnn : Result_Type; + -- declare + -- M : Mark_Id := SS_Mark; + -- L : Bignum := Lopnd; + -- begin + -- Bnn := Big_GE (L, Lbound) and then Big_LE (L, Hbound) + -- SS_Release (M); + -- end; + -- in + -- Bnn + -- end + + begin + -- Insert declaration of L into declarations of bignum block + + Insert_After + (Last (Declarations (Blk)), + Make_Object_Declaration (Loc, + Defining_Identifier => L, + Object_Definition => + New_Occurrence_Of (RTE (RE_Bignum), Loc), + Expression => Lopnd)); + + -- Insert assignment to Bnn into expressions of bignum block + + Insert_Before + (First (Statements (Handled_Statement_Sequence (Blk))), + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Bnn, Loc), + Expression => + Make_And_Then (Loc, + Left_Opnd => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Big_GE), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (L, Loc), + Lbound)), + + Right_Opnd => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Big_LE), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (L, Loc), + Hbound))))); + + -- Now rewrite the node + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Actions => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Bnn, + Object_Definition => + New_Occurrence_Of (Result_Type, Loc)), + Blk), + Expression => New_Occurrence_Of (Bnn, Loc))); + Analyze_And_Resolve (N, Result_Type); + return; + end; + + -- Here if no bignums around + + else + -- Case where types are all the same + + if Base_Type (Etype (Lop)) = Base_Type (Etype (Low_Bound (Rop))) + and then + Base_Type (Etype (Lop)) = Base_Type (Etype (High_Bound (Rop))) + then + null; + + -- If types are not all the same, it means that we have rewritten + -- at least one of them to be of type Long_Long_Integer, and we + -- will convert the other operands to Long_Long_Integer. + + else + Convert_To_And_Rewrite (LLIB, Lop); + Set_Analyzed (Lop, False); + Analyze_And_Resolve (Lop, LLIB); + + -- For the right operand, avoid unnecessary recursion into + -- this routine, we know that overflow is not possible. + + Convert_To_And_Rewrite (LLIB, Low_Bound (Rop)); + Convert_To_And_Rewrite (LLIB, High_Bound (Rop)); + Set_Analyzed (Rop, False); + Analyze_And_Resolve (Rop, LLIB, Suppress => Overflow_Check); + end if; + + -- Now the three operands are of the same signed integer type, + -- so we can use the normal expansion routine for membership, + -- setting the flag to prevent recursion into this procedure. + + Set_No_Minimize_Eliminate (N); + Expand_N_In (N); + end if; + + -- Right operand is a subtype name and the subtype has a predicate. We + -- have to make sure the predicate is checked, and for that we need to + -- use the standard N_In circuitry with appropriate types. + + else + pragma Assert (Present (Predicate_Function (Etype (Rop)))); + + -- If types are "right", just call Expand_N_In preventing recursion + + if Base_Type (Etype (Lop)) = Base_Type (Etype (Rop)) then + Set_No_Minimize_Eliminate (N); + Expand_N_In (N); + + -- Bignum case + + elsif Is_RTE (Etype (Lop), RE_Bignum) then + + -- For X in T, we want to rewrite our node as + + -- do + -- Bnn : Result_Type; + + -- declare + -- M : Mark_Id := SS_Mark; + -- Lnn : Long_Long_Integer'Base + -- Nnn : Bignum; + + -- begin + -- Nnn := X; + + -- if not Bignum_In_LLI_Range (Nnn) then + -- Bnn := False; + -- else + -- Lnn := From_Bignum (Nnn); + -- Bnn := + -- Lnn in LLIB (T'Base'First) .. LLIB (T'Base'Last) + -- and then T'Base (Lnn) in T; + -- end if; + + -- SS_Release (M); + -- end + -- in + -- Bnn + -- end + + -- A bit gruesome, but there doesn't seem to be a simpler way + + declare + Blk : constant Node_Id := Make_Bignum_Block (Loc); + Bnn : constant Entity_Id := Make_Temporary (Loc, 'B', N); + Lnn : constant Entity_Id := Make_Temporary (Loc, 'L', N); + Nnn : constant Entity_Id := Make_Temporary (Loc, 'N', N); + T : constant Entity_Id := Etype (Rop); + TB : constant Entity_Id := Base_Type (T); + Nin : Node_Id; + + begin + -- Mark the last membership operation to prevent recursion + + Nin := + Make_In (Loc, + Left_Opnd => Convert_To (TB, New_Occurrence_Of (Lnn, Loc)), + Right_Opnd => New_Occurrence_Of (T, Loc)); + Set_No_Minimize_Eliminate (Nin); + + -- Now decorate the block + + Insert_After + (Last (Declarations (Blk)), + Make_Object_Declaration (Loc, + Defining_Identifier => Lnn, + Object_Definition => New_Occurrence_Of (LLIB, Loc))); + + Insert_After + (Last (Declarations (Blk)), + Make_Object_Declaration (Loc, + Defining_Identifier => Nnn, + Object_Definition => + New_Occurrence_Of (RTE (RE_Bignum), Loc))); + + Insert_List_Before + (First (Statements (Handled_Statement_Sequence (Blk))), + New_List ( + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Nnn, Loc), + Expression => Relocate_Node (Lop)), + + Make_Implicit_If_Statement (N, + Condition => + Make_Op_Not (Loc, + Right_Opnd => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of + (RTE (RE_Bignum_In_LLI_Range), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (Nnn, Loc)))), + + Then_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Bnn, Loc), + Expression => + New_Occurrence_Of (Standard_False, Loc))), + + Else_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Lnn, Loc), + Expression => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_From_Bignum), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (Nnn, Loc)))), + + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Bnn, Loc), + Expression => + Make_And_Then (Loc, + Left_Opnd => + Make_In (Loc, + Left_Opnd => New_Occurrence_Of (Lnn, Loc), + Right_Opnd => + Make_Range (Loc, + Low_Bound => + Convert_To (LLIB, + Make_Attribute_Reference (Loc, + Attribute_Name => Name_First, + Prefix => + New_Occurrence_Of (TB, Loc))), + + High_Bound => + Convert_To (LLIB, + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Last, + Prefix => + New_Occurrence_Of (TB, Loc))))), + + Right_Opnd => Nin)))))); + + -- Now we can do the rewrite + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Actions => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Bnn, + Object_Definition => + New_Occurrence_Of (Result_Type, Loc)), + Blk), + Expression => New_Occurrence_Of (Bnn, Loc))); + Analyze_And_Resolve (N, Result_Type); + return; + end; + + -- Not bignum case, but types don't match (this means we rewrote the + -- left operand to be Long_Long_Integer). + + else + pragma Assert (Base_Type (Etype (Lop)) = LLIB); + + -- We rewrite the membership test as (where T is the type with + -- the predicate, i.e. the type of the right operand) + + -- Lop in LLIB (T'Base'First) .. LLIB (T'Base'Last) + -- and then T'Base (Lop) in T + + declare + T : constant Entity_Id := Etype (Rop); + TB : constant Entity_Id := Base_Type (T); + Nin : Node_Id; + + begin + -- The last membership test is marked to prevent recursion + + Nin := + Make_In (Loc, + Left_Opnd => Convert_To (TB, Duplicate_Subexpr (Lop)), + Right_Opnd => New_Occurrence_Of (T, Loc)); + Set_No_Minimize_Eliminate (Nin); + + -- Now do the rewrite + + Rewrite (N, + Make_And_Then (Loc, + Left_Opnd => + Make_In (Loc, + Left_Opnd => Lop, + Right_Opnd => + Make_Range (Loc, + Low_Bound => + Convert_To (LLIB, + Make_Attribute_Reference (Loc, + Attribute_Name => Name_First, + Prefix => + New_Occurrence_Of (TB, Loc))), + High_Bound => + Convert_To (LLIB, + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Last, + Prefix => + New_Occurrence_Of (TB, Loc))))), + Right_Opnd => Nin)); + Set_Analyzed (N, False); + Analyze_And_Resolve (N, Restype); + end; + end if; + end if; + end Expand_Membership_Minimize_Eliminate_Overflow; + + --------------------------------- + -- Expand_Nonbinary_Modular_Op -- + --------------------------------- + + procedure Expand_Nonbinary_Modular_Op (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + + procedure Expand_Modular_Addition; + -- Expand the modular addition, handling the special case of adding a + -- constant. + + procedure Expand_Modular_Op; + -- Compute the general rule: (lhs OP rhs) mod Modulus + + procedure Expand_Modular_Subtraction; + -- Expand the modular addition, handling the special case of subtracting + -- a constant. + + ----------------------------- + -- Expand_Modular_Addition -- + ----------------------------- + + procedure Expand_Modular_Addition is + begin + -- If this is not the addition of a constant then compute it using + -- the general rule: (lhs + rhs) mod Modulus + + if Nkind (Right_Opnd (N)) /= N_Integer_Literal then + Expand_Modular_Op; + + -- If this is an addition of a constant, convert it to a subtraction + -- plus a conditional expression since we can compute it faster than + -- computing the modulus. + + -- modMinusRhs = Modulus - rhs + -- if lhs < modMinusRhs then lhs + rhs + -- else lhs - modMinusRhs + + else + declare + Mod_Minus_Right : constant Uint := + Modulus (Typ) - Intval (Right_Opnd (N)); + + Exprs : constant List_Id := New_List; + Cond_Expr : constant Node_Id := New_Op_Node (N_Op_Lt, Loc); + Then_Expr : constant Node_Id := New_Op_Node (N_Op_Add, Loc); + Else_Expr : constant Node_Id := New_Op_Node (N_Op_Subtract, + Loc); + begin + Set_Left_Opnd (Cond_Expr, + New_Copy_Tree (Left_Opnd (N))); + Set_Right_Opnd (Cond_Expr, + Make_Integer_Literal (Loc, Mod_Minus_Right)); + Append_To (Exprs, Cond_Expr); + + Set_Left_Opnd (Then_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Then_Expr, + Make_Integer_Literal (Loc, Intval (Right_Opnd (N)))); + Append_To (Exprs, Then_Expr); + + Set_Left_Opnd (Else_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Else_Expr, + Make_Integer_Literal (Loc, Mod_Minus_Right)); + Append_To (Exprs, Else_Expr); + + Rewrite (N, + Unchecked_Convert_To (Typ, + Make_If_Expression (Loc, Expressions => Exprs))); + end; + end if; + end Expand_Modular_Addition; + + ----------------------- + -- Expand_Modular_Op -- + ----------------------- + + procedure Expand_Modular_Op is + Op_Expr : constant Node_Id := New_Op_Node (Nkind (N), Loc); + Mod_Expr : constant Node_Id := New_Op_Node (N_Op_Mod, Loc); + + begin + -- Convert nonbinary modular type operands into integer values. Thus + -- we avoid never-ending loops expanding them, and we also ensure + -- the back end never receives nonbinary modular type expressions. + + if Nkind_In (Nkind (N), N_Op_And, N_Op_Or) then + Set_Left_Opnd (Op_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Op_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Right_Opnd (N)))); + Set_Left_Opnd (Mod_Expr, + Unchecked_Convert_To (Standard_Integer, Op_Expr)); + + else + Set_Left_Opnd (Op_Expr, + Unchecked_Convert_To (Standard_Integer, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Op_Expr, + Unchecked_Convert_To (Standard_Integer, + New_Copy_Tree (Right_Opnd (N)))); + + -- Link this node to the tree to analyze it + + -- If the parent node is an expression with actions we link it to + -- N since otherwise Force_Evaluation cannot identify if this node + -- comes from the Expression and rejects generating the temporary. + + if Nkind (Parent (N)) = N_Expression_With_Actions then + Set_Parent (Op_Expr, N); + + -- Common case + + else + Set_Parent (Op_Expr, Parent (N)); + end if; + + Analyze (Op_Expr); + + -- Force generating a temporary because in the expansion of this + -- expression we may generate code that performs this computation + -- several times. + + Force_Evaluation (Op_Expr, Mode => Strict); + + Set_Left_Opnd (Mod_Expr, Op_Expr); + end if; + + Set_Right_Opnd (Mod_Expr, + Make_Integer_Literal (Loc, Modulus (Typ))); + + Rewrite (N, + Unchecked_Convert_To (Typ, Mod_Expr)); + end Expand_Modular_Op; + + -------------------------------- + -- Expand_Modular_Subtraction -- + -------------------------------- + + procedure Expand_Modular_Subtraction is + begin + -- If this is not the addition of a constant then compute it using + -- the general rule: (lhs + rhs) mod Modulus + + if Nkind (Right_Opnd (N)) /= N_Integer_Literal then + Expand_Modular_Op; + + -- If this is an addition of a constant, convert it to a subtraction + -- plus a conditional expression since we can compute it faster than + -- computing the modulus. + + -- modMinusRhs = Modulus - rhs + -- if lhs < rhs then lhs + modMinusRhs + -- else lhs - rhs + + else + declare + Mod_Minus_Right : constant Uint := + Modulus (Typ) - Intval (Right_Opnd (N)); + + Exprs : constant List_Id := New_List; + Cond_Expr : constant Node_Id := New_Op_Node (N_Op_Lt, Loc); + Then_Expr : constant Node_Id := New_Op_Node (N_Op_Add, Loc); + Else_Expr : constant Node_Id := New_Op_Node (N_Op_Subtract, + Loc); + begin + Set_Left_Opnd (Cond_Expr, + New_Copy_Tree (Left_Opnd (N))); + Set_Right_Opnd (Cond_Expr, + Make_Integer_Literal (Loc, Intval (Right_Opnd (N)))); + Append_To (Exprs, Cond_Expr); + + Set_Left_Opnd (Then_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Then_Expr, + Make_Integer_Literal (Loc, Mod_Minus_Right)); + Append_To (Exprs, Then_Expr); + + Set_Left_Opnd (Else_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Left_Opnd (N)))); + Set_Right_Opnd (Else_Expr, + Unchecked_Convert_To (Standard_Unsigned, + New_Copy_Tree (Right_Opnd (N)))); + Append_To (Exprs, Else_Expr); + + Rewrite (N, + Unchecked_Convert_To (Typ, + Make_If_Expression (Loc, Expressions => Exprs))); + end; + end if; + end Expand_Modular_Subtraction; + + -- Start of processing for Expand_Nonbinary_Modular_Op + + begin + -- No action needed if we are not generating C code for a nonbinary + -- modular operand. + + if not Modify_Tree_For_C + or else not Non_Binary_Modulus (Typ) + then + return; + end if; + + case Nkind (N) is + when N_Op_Add => + Expand_Modular_Addition; + + when N_Op_Subtract => + Expand_Modular_Subtraction; + + when N_Op_Minus => + + -- Expand -expr into (0 - expr) + + Rewrite (N, + Make_Op_Subtract (Loc, + Left_Opnd => Make_Integer_Literal (Loc, 0), + Right_Opnd => Right_Opnd (N))); + Analyze_And_Resolve (N, Typ); + + when others => + Expand_Modular_Op; + end case; + + Analyze_And_Resolve (N, Typ); + end Expand_Nonbinary_Modular_Op; + + ------------------------ + -- Expand_N_Allocator -- + ------------------------ + + procedure Expand_N_Allocator (N : Node_Id) is + Etyp : constant Entity_Id := Etype (Expression (N)); + Loc : constant Source_Ptr := Sloc (N); + PtrT : constant Entity_Id := Etype (N); + + procedure Rewrite_Coextension (N : Node_Id); + -- Static coextensions have the same lifetime as the entity they + -- constrain. Such occurrences can be rewritten as aliased objects + -- and their unrestricted access used instead of the coextension. + + function Size_In_Storage_Elements (E : Entity_Id) return Node_Id; + -- Given a constrained array type E, returns a node representing the + -- code to compute the size in storage elements for the given type. + -- This is done without using the attribute (which malfunctions for + -- large sizes ???) + + ------------------------- + -- Rewrite_Coextension -- + ------------------------- + + procedure Rewrite_Coextension (N : Node_Id) is + Temp_Id : constant Node_Id := Make_Temporary (Loc, 'C'); + Temp_Decl : Node_Id; + + begin + -- Generate: + -- Cnn : aliased Etyp; + + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp_Id, + Aliased_Present => True, + Object_Definition => New_Occurrence_Of (Etyp, Loc)); + + if Nkind (Expression (N)) = N_Qualified_Expression then + Set_Expression (Temp_Decl, Expression (Expression (N))); + end if; + + Insert_Action (N, Temp_Decl); + Rewrite (N, + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Temp_Id, Loc), + Attribute_Name => Name_Unrestricted_Access)); + + Analyze_And_Resolve (N, PtrT); + end Rewrite_Coextension; + + ------------------------------ + -- Size_In_Storage_Elements -- + ------------------------------ + + function Size_In_Storage_Elements (E : Entity_Id) return Node_Id is + begin + -- Logically this just returns E'Max_Size_In_Storage_Elements. + -- However, the reason for the existence of this function is + -- to construct a test for sizes too large, which means near the + -- 32-bit limit on a 32-bit machine, and precisely the trouble + -- is that we get overflows when sizes are greater than 2**31. + + -- So what we end up doing for array types is to use the expression: + + -- number-of-elements * component_type'Max_Size_In_Storage_Elements + + -- which avoids this problem. All this is a bit bogus, but it does + -- mean we catch common cases of trying to allocate arrays that + -- are too large, and which in the absence of a check results in + -- undetected chaos ??? + + -- Note in particular that this is a pessimistic estimate in the + -- case of packed array types, where an array element might occupy + -- just a fraction of a storage element??? + + declare + Len : Node_Id; + Res : Node_Id; + pragma Warnings (Off, Res); + + begin + for J in 1 .. Number_Dimensions (E) loop + Len := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (E, Loc), + Attribute_Name => Name_Length, + Expressions => New_List (Make_Integer_Literal (Loc, J))); + + if J = 1 then + Res := Len; + + else + Res := + Make_Op_Multiply (Loc, + Left_Opnd => Res, + Right_Opnd => Len); + end if; + end loop; + + return + Make_Op_Multiply (Loc, + Left_Opnd => Len, + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Component_Type (E), Loc), + Attribute_Name => Name_Max_Size_In_Storage_Elements)); + end; + end Size_In_Storage_Elements; + + -- Local variables + + Dtyp : constant Entity_Id := Available_View (Designated_Type (PtrT)); + Desig : Entity_Id; + Nod : Node_Id; + Pool : Entity_Id; + Rel_Typ : Entity_Id; + Temp : Entity_Id; + + -- Start of processing for Expand_N_Allocator + + begin + -- RM E.2.3(22). We enforce that the expected type of an allocator + -- shall not be a remote access-to-class-wide-limited-private type + + -- Why is this being done at expansion time, seems clearly wrong ??? + + Validate_Remote_Access_To_Class_Wide_Type (N); + + -- Processing for anonymous access-to-controlled types. These access + -- types receive a special finalization master which appears in the + -- declarations of the enclosing semantic unit. This expansion is done + -- now to ensure that any additional types generated by this routine or + -- Expand_Allocator_Expression inherit the proper type attributes. + + if (Ekind (PtrT) = E_Anonymous_Access_Type + or else (Is_Itype (PtrT) and then No (Finalization_Master (PtrT)))) + and then Needs_Finalization (Dtyp) + then + -- Detect the allocation of an anonymous controlled object where the + -- type of the context is named. For example: + + -- procedure Proc (Ptr : Named_Access_Typ); + -- Proc (new Designated_Typ); + + -- Regardless of the anonymous-to-named access type conversion, the + -- lifetime of the object must be associated with the named access + -- type. Use the finalization-related attributes of this type. + + if Nkind_In (Parent (N), N_Type_Conversion, + N_Unchecked_Type_Conversion) + and then Ekind_In (Etype (Parent (N)), E_Access_Subtype, + E_Access_Type, + E_General_Access_Type) + then + Rel_Typ := Etype (Parent (N)); + else + Rel_Typ := Empty; + end if; + + -- Anonymous access-to-controlled types allocate on the global pool. + -- Note that this is a "root type only" attribute. + + if No (Associated_Storage_Pool (PtrT)) then + if Present (Rel_Typ) then + Set_Associated_Storage_Pool + (Root_Type (PtrT), Associated_Storage_Pool (Rel_Typ)); + else + Set_Associated_Storage_Pool + (Root_Type (PtrT), RTE (RE_Global_Pool_Object)); + end if; + end if; + + -- The finalization master must be inserted and analyzed as part of + -- the current semantic unit. Note that the master is updated when + -- analysis changes current units. Note that this is a "root type + -- only" attribute. + + if Present (Rel_Typ) then + Set_Finalization_Master + (Root_Type (PtrT), Finalization_Master (Rel_Typ)); + else + Build_Anonymous_Master (Root_Type (PtrT)); + end if; + end if; + + -- Set the storage pool and find the appropriate version of Allocate to + -- call. Do not overwrite the storage pool if it is already set, which + -- can happen for build-in-place function returns (see + -- Exp_Ch4.Expand_N_Extended_Return_Statement). + + if No (Storage_Pool (N)) then + Pool := Associated_Storage_Pool (Root_Type (PtrT)); + + if Present (Pool) then + Set_Storage_Pool (N, Pool); + + if Is_RTE (Pool, RE_SS_Pool) then + Set_Procedure_To_Call (N, RTE (RE_SS_Allocate)); + + -- In the case of an allocator for a simple storage pool, locate + -- and save a reference to the pool type's Allocate routine. + + elsif Present (Get_Rep_Pragma + (Etype (Pool), Name_Simple_Storage_Pool_Type)) + then + declare + Pool_Type : constant Entity_Id := Base_Type (Etype (Pool)); + Alloc_Op : Entity_Id; + begin + Alloc_Op := Get_Name_Entity_Id (Name_Allocate); + while Present (Alloc_Op) loop + if Scope (Alloc_Op) = Scope (Pool_Type) + and then Present (First_Formal (Alloc_Op)) + and then Etype (First_Formal (Alloc_Op)) = Pool_Type + then + Set_Procedure_To_Call (N, Alloc_Op); + exit; + else + Alloc_Op := Homonym (Alloc_Op); + end if; + end loop; + end; + + elsif Is_Class_Wide_Type (Etype (Pool)) then + Set_Procedure_To_Call (N, RTE (RE_Allocate_Any)); + + else + Set_Procedure_To_Call (N, + Find_Prim_Op (Etype (Pool), Name_Allocate)); + end if; + end if; + end if; + + -- Under certain circumstances we can replace an allocator by an access + -- to statically allocated storage. The conditions, as noted in AARM + -- 3.10 (10c) are as follows: + + -- Size and initial value is known at compile time + -- Access type is access-to-constant + + -- The allocator is not part of a constraint on a record component, + -- because in that case the inserted actions are delayed until the + -- record declaration is fully analyzed, which is too late for the + -- analysis of the rewritten allocator. + + if Is_Access_Constant (PtrT) + and then Nkind (Expression (N)) = N_Qualified_Expression + and then Compile_Time_Known_Value (Expression (Expression (N))) + and then Size_Known_At_Compile_Time + (Etype (Expression (Expression (N)))) + and then not Is_Record_Type (Current_Scope) + then + -- Here we can do the optimization. For the allocator + + -- new x'(y) + + -- We insert an object declaration + + -- Tnn : aliased x := y; + + -- and replace the allocator by Tnn'Unrestricted_Access. Tnn is + -- marked as requiring static allocation. + + Temp := Make_Temporary (Loc, 'T', Expression (Expression (N))); + Desig := Subtype_Mark (Expression (N)); + + -- If context is constrained, use constrained subtype directly, + -- so that the constant is not labelled as having a nominally + -- unconstrained subtype. + + if Entity (Desig) = Base_Type (Dtyp) then + Desig := New_Occurrence_Of (Dtyp, Loc); + end if; + + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Aliased_Present => True, + Constant_Present => Is_Access_Constant (PtrT), + Object_Definition => Desig, + Expression => Expression (Expression (N)))); + + Rewrite (N, + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Temp, Loc), + Attribute_Name => Name_Unrestricted_Access)); + + Analyze_And_Resolve (N, PtrT); + + -- We set the variable as statically allocated, since we don't want + -- it going on the stack of the current procedure. + + Set_Is_Statically_Allocated (Temp); + return; + end if; + + -- Same if the allocator is an access discriminant for a local object: + -- instead of an allocator we create a local value and constrain the + -- enclosing object with the corresponding access attribute. + + if Is_Static_Coextension (N) then + Rewrite_Coextension (N); + return; + end if; + + -- Check for size too large, we do this because the back end misses + -- proper checks here and can generate rubbish allocation calls when + -- we are near the limit. We only do this for the 32-bit address case + -- since that is from a practical point of view where we see a problem. + + if System_Address_Size = 32 + and then not Storage_Checks_Suppressed (PtrT) + and then not Storage_Checks_Suppressed (Dtyp) + and then not Storage_Checks_Suppressed (Etyp) + then + -- The check we want to generate should look like + + -- if Etyp'Max_Size_In_Storage_Elements > 3.5 gigabytes then + -- raise Storage_Error; + -- end if; + + -- where 3.5 gigabytes is a constant large enough to accommodate any + -- reasonable request for. But we can't do it this way because at + -- least at the moment we don't compute this attribute right, and + -- can silently give wrong results when the result gets large. Since + -- this is all about large results, that's bad, so instead we only + -- apply the check for constrained arrays, and manually compute the + -- value of the attribute ??? + + if Is_Array_Type (Etyp) and then Is_Constrained (Etyp) then + Insert_Action (N, + Make_Raise_Storage_Error (Loc, + Condition => + Make_Op_Gt (Loc, + Left_Opnd => Size_In_Storage_Elements (Etyp), + Right_Opnd => + Make_Integer_Literal (Loc, Uint_7 * (Uint_2 ** 29))), + Reason => SE_Object_Too_Large)); + end if; + end if; + + -- If no storage pool has been specified and we have the restriction + -- No_Standard_Allocators_After_Elaboration is present, then generate + -- a call to Elaboration_Allocators.Check_Standard_Allocator. + + if Nkind (N) = N_Allocator + and then No (Storage_Pool (N)) + and then Restriction_Active (No_Standard_Allocators_After_Elaboration) + then + Insert_Action (N, + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (RTE (RE_Check_Standard_Allocator), Loc))); + end if; + + -- Handle case of qualified expression (other than optimization above) + -- First apply constraint checks, because the bounds or discriminants + -- in the aggregate might not match the subtype mark in the allocator. + + if Nkind (Expression (N)) = N_Qualified_Expression then + declare + Exp : constant Node_Id := Expression (Expression (N)); + Typ : constant Entity_Id := Etype (Expression (N)); + + begin + Apply_Constraint_Check (Exp, Typ); + Apply_Predicate_Check (Exp, Typ); + end; + + Expand_Allocator_Expression (N); + return; + end if; + + -- If the allocator is for a type which requires initialization, and + -- there is no initial value (i.e. operand is a subtype indication + -- rather than a qualified expression), then we must generate a call to + -- the initialization routine using an expressions action node: + + -- [Pnnn : constant ptr_T := new (T); Init (Pnnn.all,...); Pnnn] + + -- Here ptr_T is the pointer type for the allocator, and T is the + -- subtype of the allocator. A special case arises if the designated + -- type of the access type is a task or contains tasks. In this case + -- the call to Init (Temp.all ...) is replaced by code that ensures + -- that tasks get activated (see Exp_Ch9.Build_Task_Allocate_Block + -- for details). In addition, if the type T is a task type, then the + -- first argument to Init must be converted to the task record type. + + declare + T : constant Entity_Id := Entity (Expression (N)); + Args : List_Id; + Decls : List_Id; + Decl : Node_Id; + Discr : Elmt_Id; + Init : Entity_Id; + Init_Arg1 : Node_Id; + Init_Call : Node_Id; + Temp_Decl : Node_Id; + Temp_Type : Entity_Id; + + begin + if No_Initialization (N) then + + -- Even though this might be a simple allocation, create a custom + -- Allocate if the context requires it. + + if Present (Finalization_Master (PtrT)) then + Build_Allocate_Deallocate_Proc + (N => N, + Is_Allocate => True); + end if; + + -- Case of no initialization procedure present + + elsif not Has_Non_Null_Base_Init_Proc (T) then + + -- Case of simple initialization required + + if Needs_Simple_Initialization (T) then + Check_Restriction (No_Default_Initialization, N); + Rewrite (Expression (N), + Make_Qualified_Expression (Loc, + Subtype_Mark => New_Occurrence_Of (T, Loc), + Expression => Get_Simple_Init_Val (T, N))); + + Analyze_And_Resolve (Expression (Expression (N)), T); + Analyze_And_Resolve (Expression (N), T); + Set_Paren_Count (Expression (Expression (N)), 1); + Expand_N_Allocator (N); + + -- No initialization required + + else + Build_Allocate_Deallocate_Proc + (N => N, + Is_Allocate => True); + end if; + + -- Case of initialization procedure present, must be called + + else + Check_Restriction (No_Default_Initialization, N); + + if not Restriction_Active (No_Default_Initialization) then + Init := Base_Init_Proc (T); + Nod := N; + Temp := Make_Temporary (Loc, 'P'); + + -- Construct argument list for the initialization routine call + + Init_Arg1 := + Make_Explicit_Dereference (Loc, + Prefix => + New_Occurrence_Of (Temp, Loc)); + + Set_Assignment_OK (Init_Arg1); + Temp_Type := PtrT; + + -- The initialization procedure expects a specific type. if the + -- context is access to class wide, indicate that the object + -- being allocated has the right specific type. + + if Is_Class_Wide_Type (Dtyp) then + Init_Arg1 := Unchecked_Convert_To (T, Init_Arg1); + end if; + + -- If designated type is a concurrent type or if it is private + -- type whose definition is a concurrent type, the first + -- argument in the Init routine has to be unchecked conversion + -- to the corresponding record type. If the designated type is + -- a derived type, also convert the argument to its root type. + + if Is_Concurrent_Type (T) then + Init_Arg1 := + Unchecked_Convert_To ( + Corresponding_Record_Type (T), Init_Arg1); + + elsif Is_Private_Type (T) + and then Present (Full_View (T)) + and then Is_Concurrent_Type (Full_View (T)) + then + Init_Arg1 := + Unchecked_Convert_To + (Corresponding_Record_Type (Full_View (T)), Init_Arg1); + + elsif Etype (First_Formal (Init)) /= Base_Type (T) then + declare + Ftyp : constant Entity_Id := Etype (First_Formal (Init)); + + begin + Init_Arg1 := OK_Convert_To (Etype (Ftyp), Init_Arg1); + Set_Etype (Init_Arg1, Ftyp); + end; + end if; + + Args := New_List (Init_Arg1); + + -- For the task case, pass the Master_Id of the access type as + -- the value of the _Master parameter, and _Chain as the value + -- of the _Chain parameter (_Chain will be defined as part of + -- the generated code for the allocator). + + -- In Ada 2005, the context may be a function that returns an + -- anonymous access type. In that case the Master_Id has been + -- created when expanding the function declaration. + + if Has_Task (T) then + if No (Master_Id (Base_Type (PtrT))) then + + -- The designated type was an incomplete type, and the + -- access type did not get expanded. Salvage it now. + + if not Restriction_Active (No_Task_Hierarchy) then + if Present (Parent (Base_Type (PtrT))) then + Expand_N_Full_Type_Declaration + (Parent (Base_Type (PtrT))); + + -- The only other possibility is an itype. For this + -- case, the master must exist in the context. This is + -- the case when the allocator initializes an access + -- component in an init-proc. + + else + pragma Assert (Is_Itype (PtrT)); + Build_Master_Renaming (PtrT, N); + end if; + end if; + end if; + + -- If the context of the allocator is a declaration or an + -- assignment, we can generate a meaningful image for it, + -- even though subsequent assignments might remove the + -- connection between task and entity. We build this image + -- when the left-hand side is a simple variable, a simple + -- indexed assignment or a simple selected component. + + if Nkind (Parent (N)) = N_Assignment_Statement then + declare + Nam : constant Node_Id := Name (Parent (N)); + + begin + if Is_Entity_Name (Nam) then + Decls := + Build_Task_Image_Decls + (Loc, + New_Occurrence_Of + (Entity (Nam), Sloc (Nam)), T); + + elsif Nkind_In (Nam, N_Indexed_Component, + N_Selected_Component) + and then Is_Entity_Name (Prefix (Nam)) + then + Decls := + Build_Task_Image_Decls + (Loc, Nam, Etype (Prefix (Nam))); + else + Decls := Build_Task_Image_Decls (Loc, T, T); + end if; + end; + + elsif Nkind (Parent (N)) = N_Object_Declaration then + Decls := + Build_Task_Image_Decls + (Loc, Defining_Identifier (Parent (N)), T); + + else + Decls := Build_Task_Image_Decls (Loc, T, T); + end if; + + if Restriction_Active (No_Task_Hierarchy) then + Append_To (Args, + New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc)); + else + Append_To (Args, + New_Occurrence_Of + (Master_Id (Base_Type (Root_Type (PtrT))), Loc)); + end if; + + Append_To (Args, Make_Identifier (Loc, Name_uChain)); + + Decl := Last (Decls); + Append_To (Args, + New_Occurrence_Of (Defining_Identifier (Decl), Loc)); + + -- Has_Task is false, Decls not used + + else + Decls := No_List; + end if; + + -- Add discriminants if discriminated type + + declare + Dis : Boolean := False; + Typ : Entity_Id; + + begin + if Has_Discriminants (T) then + Dis := True; + Typ := T; + + -- Type may be a private type with no visible discriminants + -- in which case check full view if in scope, or the + -- underlying_full_view if dealing with a type whose full + -- view may be derived from a private type whose own full + -- view has discriminants. + + elsif Is_Private_Type (T) then + if Present (Full_View (T)) + and then Has_Discriminants (Full_View (T)) + then + Dis := True; + Typ := Full_View (T); + + elsif Present (Underlying_Full_View (T)) + and then Has_Discriminants (Underlying_Full_View (T)) + then + Dis := True; + Typ := Underlying_Full_View (T); + end if; + end if; + + if Dis then + + -- If the allocated object will be constrained by the + -- default values for discriminants, then build a subtype + -- with those defaults, and change the allocated subtype + -- to that. Note that this happens in fewer cases in Ada + -- 2005 (AI-363). + + if not Is_Constrained (Typ) + and then Present (Discriminant_Default_Value + (First_Discriminant (Typ))) + and then (Ada_Version < Ada_2005 + or else not + Object_Type_Has_Constrained_Partial_View + (Typ, Current_Scope)) + then + Typ := Build_Default_Subtype (Typ, N); + Set_Expression (N, New_Occurrence_Of (Typ, Loc)); + end if; + + Discr := First_Elmt (Discriminant_Constraint (Typ)); + while Present (Discr) loop + Nod := Node (Discr); + Append (New_Copy_Tree (Node (Discr)), Args); + + -- AI-416: when the discriminant constraint is an + -- anonymous access type make sure an accessibility + -- check is inserted if necessary (3.10.2(22.q/2)) + + if Ada_Version >= Ada_2005 + and then + Ekind (Etype (Nod)) = E_Anonymous_Access_Type + then + Apply_Accessibility_Check + (Nod, Typ, Insert_Node => Nod); + end if; + + Next_Elmt (Discr); + end loop; + end if; + end; + + -- We set the allocator as analyzed so that when we analyze + -- the if expression node, we do not get an unwanted recursive + -- expansion of the allocator expression. + + Set_Analyzed (N, True); + Nod := Relocate_Node (N); + + -- Here is the transformation: + -- input: new Ctrl_Typ + -- output: Temp : constant Ctrl_Typ_Ptr := new Ctrl_Typ; + -- Ctrl_TypIP (Temp.all, ...); + -- [Deep_]Initialize (Temp.all); + + -- Here Ctrl_Typ_Ptr is the pointer type for the allocator, and + -- is the subtype of the allocator. + + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Temp_Type, Loc), + Expression => Nod); + + Set_Assignment_OK (Temp_Decl); + Insert_Action (N, Temp_Decl, Suppress => All_Checks); + + Build_Allocate_Deallocate_Proc (Temp_Decl, True); + + -- If the designated type is a task type or contains tasks, + -- create block to activate created tasks, and insert + -- declaration for Task_Image variable ahead of call. + + if Has_Task (T) then + declare + L : constant List_Id := New_List; + Blk : Node_Id; + begin + Build_Task_Allocate_Block (L, Nod, Args); + Blk := Last (L); + Insert_List_Before (First (Declarations (Blk)), Decls); + Insert_Actions (N, L); + end; + + else + Insert_Action (N, + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Init, Loc), + Parameter_Associations => Args)); + end if; + + if Needs_Finalization (T) then + + -- Generate: + -- [Deep_]Initialize (Init_Arg1); + + Init_Call := + Make_Init_Call + (Obj_Ref => New_Copy_Tree (Init_Arg1), + Typ => T); + + -- Guard against a missing [Deep_]Initialize when the + -- designated type was not properly frozen. + + if Present (Init_Call) then + Insert_Action (N, Init_Call); + end if; + end if; + + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + Analyze_And_Resolve (N, PtrT); + end if; + end if; + end; + + -- Ada 2005 (AI-251): If the allocator is for a class-wide interface + -- object that has been rewritten as a reference, we displace "this" + -- to reference properly its secondary dispatch table. + + if Nkind (N) = N_Identifier and then Is_Interface (Dtyp) then + Displace_Allocator_Pointer (N); + end if; + + exception + when RE_Not_Available => + return; + end Expand_N_Allocator; + + ----------------------- + -- Expand_N_And_Then -- + ----------------------- + + procedure Expand_N_And_Then (N : Node_Id) + renames Expand_Short_Circuit_Operator; + + ------------------------------ + -- Expand_N_Case_Expression -- + ------------------------------ + + procedure Expand_N_Case_Expression (N : Node_Id) is + + function Is_Copy_Type (Typ : Entity_Id) return Boolean; + -- Return True if we can copy objects of this type when expanding a case + -- expression. + + ------------------ + -- Is_Copy_Type -- + ------------------ + + function Is_Copy_Type (Typ : Entity_Id) return Boolean is + begin + -- If Minimize_Expression_With_Actions is True, we can afford to copy + -- large objects, as long as they are constrained and not limited. + + return + Is_Elementary_Type (Underlying_Type (Typ)) + or else + (Minimize_Expression_With_Actions + and then Is_Constrained (Underlying_Type (Typ)) + and then not Is_Limited_View (Underlying_Type (Typ))); + end Is_Copy_Type; + + -- Local variables + + Loc : constant Source_Ptr := Sloc (N); + Par : constant Node_Id := Parent (N); + Typ : constant Entity_Id := Etype (N); + + Acts : List_Id; + Alt : Node_Id; + Case_Stmt : Node_Id; + Decl : Node_Id; + Expr : Node_Id; + Target : Entity_Id; + Target_Typ : Entity_Id; + + In_Predicate : Boolean := False; + -- Flag set when the case expression appears within a predicate + + Optimize_Return_Stmt : Boolean := False; + -- Flag set when the case expression can be optimized in the context of + -- a simple return statement. + + -- Start of processing for Expand_N_Case_Expression + + begin + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- If the case expression is a predicate specification, and the type + -- to which it applies has a static predicate aspect, do not expand, + -- because it will be converted to the proper predicate form later. + + if Ekind_In (Current_Scope, E_Function, E_Procedure) + and then Is_Predicate_Function (Current_Scope) + then + In_Predicate := True; + + if Has_Static_Predicate_Aspect (Etype (First_Entity (Current_Scope))) + then + return; + end if; + end if; + + -- When the type of the case expression is elementary, expand + + -- (case X is when A => AX, when B => BX ...) + + -- into + + -- do + -- Target : Typ; + -- case X is + -- when A => + -- Target := AX; + -- when B => + -- Target := BX; + -- ... + -- end case; + -- in Target end; + + -- In all other cases expand into + + -- do + -- type Ptr_Typ is access all Typ; + -- Target : Ptr_Typ; + -- case X is + -- when A => + -- Target := AX'Unrestricted_Access; + -- when B => + -- Target := BX'Unrestricted_Access; + -- ... + -- end case; + -- in Target.all end; + + -- This approach avoids extra copies of potentially large objects. It + -- also allows handling of values of limited or unconstrained types. + -- Note that we do the copy also for constrained, nonlimited types + -- when minimizing expressions with actions (e.g. when generating C + -- code) since it allows us to do the optimization below in more cases. + + -- Small optimization: when the case expression appears in the context + -- of a simple return statement, expand into + + -- case X is + -- when A => + -- return AX; + -- when B => + -- return BX; + -- ... + -- end case; + + Case_Stmt := + Make_Case_Statement (Loc, + Expression => Expression (N), + Alternatives => New_List); + + -- Preserve the original context for which the case statement is being + -- generated. This is needed by the finalization machinery to prevent + -- the premature finalization of controlled objects found within the + -- case statement. + + Set_From_Conditional_Expression (Case_Stmt); + Acts := New_List; + + -- Scalar/Copy case + + if Is_Copy_Type (Typ) then + Target_Typ := Typ; + + -- ??? Do not perform the optimization when the return statement is + -- within a predicate function, as this causes spurious errors. Could + -- this be a possible mismatch in handling this case somewhere else + -- in semantic analysis? + + Optimize_Return_Stmt := + Nkind (Par) = N_Simple_Return_Statement and then not In_Predicate; + + -- Otherwise create an access type to handle the general case using + -- 'Unrestricted_Access. + + -- Generate: + -- type Ptr_Typ is access all Typ; + + else + if Generate_C_Code then + + -- We cannot ensure that correct C code will be generated if any + -- temporary is created down the line (to e.g. handle checks or + -- capture values) since we might end up with dangling references + -- to local variables, so better be safe and reject the construct. + + Error_Msg_N + ("case expression too complex, use case statement instead", N); + end if; + + Target_Typ := Make_Temporary (Loc, 'P'); + + Append_To (Acts, + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Target_Typ, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Subtype_Indication => New_Occurrence_Of (Typ, Loc)))); + end if; + + -- Create the declaration of the target which captures the value of the + -- expression. + + -- Generate: + -- Target : [Ptr_]Typ; + + if not Optimize_Return_Stmt then + Target := Make_Temporary (Loc, 'T'); + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Target, + Object_Definition => New_Occurrence_Of (Target_Typ, Loc)); + Set_No_Initialization (Decl); + + Append_To (Acts, Decl); + end if; + + -- Process the alternatives + + Alt := First (Alternatives (N)); + while Present (Alt) loop + declare + Alt_Expr : Node_Id := Expression (Alt); + Alt_Loc : constant Source_Ptr := Sloc (Alt_Expr); + Stmts : List_Id; + + begin + -- Take the unrestricted access of the expression value for non- + -- scalar types. This approach avoids big copies and covers the + -- limited and unconstrained cases. + + -- Generate: + -- AX'Unrestricted_Access + + if not Is_Copy_Type (Typ) then + Alt_Expr := + Make_Attribute_Reference (Alt_Loc, + Prefix => Relocate_Node (Alt_Expr), + Attribute_Name => Name_Unrestricted_Access); + end if; + + -- Generate: + -- return AX['Unrestricted_Access]; + + if Optimize_Return_Stmt then + Stmts := New_List ( + Make_Simple_Return_Statement (Alt_Loc, + Expression => Alt_Expr)); + + -- Generate: + -- Target := AX['Unrestricted_Access]; + + else + Stmts := New_List ( + Make_Assignment_Statement (Alt_Loc, + Name => New_Occurrence_Of (Target, Loc), + Expression => Alt_Expr)); + end if; + + -- Propagate declarations inserted in the node by Insert_Actions + -- (for example, temporaries generated to remove side effects). + -- These actions must remain attached to the alternative, given + -- that they are generated by the corresponding expression. + + if Present (Actions (Alt)) then + Prepend_List (Actions (Alt), Stmts); + end if; + + -- Finalize any transient objects on exit from the alternative. + -- This is done only in the return optimization case because + -- otherwise the case expression is converted into an expression + -- with actions which already contains this form of processing. + + if Optimize_Return_Stmt then + Process_If_Case_Statements (N, Stmts); + end if; + + Append_To + (Alternatives (Case_Stmt), + Make_Case_Statement_Alternative (Sloc (Alt), + Discrete_Choices => Discrete_Choices (Alt), + Statements => Stmts)); + end; + + Next (Alt); + end loop; + + -- Rewrite the parent return statement as a case statement + + if Optimize_Return_Stmt then + Rewrite (Par, Case_Stmt); + Analyze (Par); + + -- Otherwise convert the case expression into an expression with actions + + else + Append_To (Acts, Case_Stmt); + + if Is_Copy_Type (Typ) then + Expr := New_Occurrence_Of (Target, Loc); + + else + Expr := + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Target, Loc)); + end if; + + -- Generate: + -- do + -- ... + -- in Target[.all] end; + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Expression => Expr, + Actions => Acts)); + + Analyze_And_Resolve (N, Typ); + end if; + end Expand_N_Case_Expression; + + ----------------------------------- + -- Expand_N_Explicit_Dereference -- + ----------------------------------- + + procedure Expand_N_Explicit_Dereference (N : Node_Id) is + begin + -- Insert explicit dereference call for the checked storage pool case + + Insert_Dereference_Action (Prefix (N)); + + -- If the type is an Atomic type for which Atomic_Sync is enabled, then + -- we set the atomic sync flag. + + if Is_Atomic (Etype (N)) + and then not Atomic_Synchronization_Disabled (Etype (N)) + then + Activate_Atomic_Synchronization (N); + end if; + end Expand_N_Explicit_Dereference; + + -------------------------------------- + -- Expand_N_Expression_With_Actions -- + -------------------------------------- + + procedure Expand_N_Expression_With_Actions (N : Node_Id) is + Acts : constant List_Id := Actions (N); + + procedure Force_Boolean_Evaluation (Expr : Node_Id); + -- Force the evaluation of Boolean expression Expr + + function Process_Action (Act : Node_Id) return Traverse_Result; + -- Inspect and process a single action of an expression_with_actions for + -- transient objects. If such objects are found, the routine generates + -- code to clean them up when the context of the expression is evaluated + -- or elaborated. + + ------------------------------ + -- Force_Boolean_Evaluation -- + ------------------------------ + + procedure Force_Boolean_Evaluation (Expr : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Flag_Decl : Node_Id; + Flag_Id : Entity_Id; + + begin + -- Relocate the expression to the actions list by capturing its value + -- in a Boolean flag. Generate: + -- Flag : constant Boolean := Expr; + + Flag_Id := Make_Temporary (Loc, 'F'); + + Flag_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Flag_Id, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), + Expression => Relocate_Node (Expr)); + + Append (Flag_Decl, Acts); + Analyze (Flag_Decl); + + -- Replace the expression with a reference to the flag + + Rewrite (Expression (N), New_Occurrence_Of (Flag_Id, Loc)); + Analyze (Expression (N)); + end Force_Boolean_Evaluation; + + -------------------- + -- Process_Action -- + -------------------- + + function Process_Action (Act : Node_Id) return Traverse_Result is + begin + if Nkind (Act) = N_Object_Declaration + and then Is_Finalizable_Transient (Act, N) + then + Process_Transient_In_Expression (Act, N, Acts); + return Abandon; + + -- Avoid processing temporary function results multiple times when + -- dealing with nested expression_with_actions. + + elsif Nkind (Act) = N_Expression_With_Actions then + return Abandon; + + -- Do not process temporary function results in loops. This is done + -- by Expand_N_Loop_Statement and Build_Finalizer. + + elsif Nkind (Act) = N_Loop_Statement then + return Abandon; + end if; + + return OK; + end Process_Action; + + procedure Process_Single_Action is new Traverse_Proc (Process_Action); + + -- Local variables + + Act : Node_Id; + + -- Start of processing for Expand_N_Expression_With_Actions + + begin + -- Do not evaluate the expression when it denotes an entity because the + -- expression_with_actions node will be replaced by the reference. + + if Is_Entity_Name (Expression (N)) then + null; + + -- Do not evaluate the expression when there are no actions because the + -- expression_with_actions node will be replaced by the expression. + + elsif No (Acts) or else Is_Empty_List (Acts) then + null; + + -- Force the evaluation of the expression by capturing its value in a + -- temporary. This ensures that aliases of transient objects do not leak + -- to the expression of the expression_with_actions node: + + -- do + -- Trans_Id : Ctrl_Typ := ...; + -- Alias : ... := Trans_Id; + -- in ... Alias ... end; + + -- In the example above, Trans_Id cannot be finalized at the end of the + -- actions list because this may affect the alias and the final value of + -- the expression_with_actions. Forcing the evaluation encapsulates the + -- reference to the Alias within the actions list: + + -- do + -- Trans_Id : Ctrl_Typ := ...; + -- Alias : ... := Trans_Id; + -- Val : constant Boolean := ... Alias ...; + -- <finalize Trans_Id> + -- in Val end; + + -- Once this transformation is performed, it is safe to finalize the + -- transient object at the end of the actions list. + + -- Note that Force_Evaluation does not remove side effects in operators + -- because it assumes that all operands are evaluated and side effect + -- free. This is not the case when an operand depends implicitly on the + -- transient object through the use of access types. + + elsif Is_Boolean_Type (Etype (Expression (N))) then + Force_Boolean_Evaluation (Expression (N)); + + -- The expression of an expression_with_actions node may not necessarily + -- be Boolean when the node appears in an if expression. In this case do + -- the usual forced evaluation to encapsulate potential aliasing. + + else + Force_Evaluation (Expression (N)); + end if; + + -- Process all transient objects found within the actions of the EWA + -- node. + + Act := First (Acts); + while Present (Act) loop + Process_Single_Action (Act); + Next (Act); + end loop; + + -- Deal with case where there are no actions. In this case we simply + -- rewrite the node with its expression since we don't need the actions + -- and the specification of this node does not allow a null action list. + + -- Note: we use Rewrite instead of Replace, because Codepeer is using + -- the expanded tree and relying on being able to retrieve the original + -- tree in cases like this. This raises a whole lot of issues of whether + -- we have problems elsewhere, which will be addressed in the future??? + + if Is_Empty_List (Acts) then + Rewrite (N, Relocate_Node (Expression (N))); + end if; + end Expand_N_Expression_With_Actions; + + ---------------------------- + -- Expand_N_If_Expression -- + ---------------------------- + + -- Deal with limited types and condition actions + + procedure Expand_N_If_Expression (N : Node_Id) is + Cond : constant Node_Id := First (Expressions (N)); + Loc : constant Source_Ptr := Sloc (N); + Thenx : constant Node_Id := Next (Cond); + Elsex : constant Node_Id := Next (Thenx); + Typ : constant Entity_Id := Etype (N); + + Actions : List_Id; + Decl : Node_Id; + Expr : Node_Id; + New_If : Node_Id; + New_N : Node_Id; + + begin + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Fold at compile time if condition known. We have already folded + -- static if expressions, but it is possible to fold any case in which + -- the condition is known at compile time, even though the result is + -- non-static. + + -- Note that we don't do the fold of such cases in Sem_Elab because + -- it can cause infinite loops with the expander adding a conditional + -- expression, and Sem_Elab circuitry removing it repeatedly. + + if Compile_Time_Known_Value (Cond) then + declare + function Fold_Known_Value (Cond : Node_Id) return Boolean; + -- Fold at compile time. Assumes condition known. Return True if + -- folding occurred, meaning we're done. + + ---------------------- + -- Fold_Known_Value -- + ---------------------- + + function Fold_Known_Value (Cond : Node_Id) return Boolean is + begin + if Is_True (Expr_Value (Cond)) then + Expr := Thenx; + Actions := Then_Actions (N); + else + Expr := Elsex; + Actions := Else_Actions (N); + end if; + + Remove (Expr); + + if Present (Actions) then + + -- To minimize the use of Expression_With_Actions, just skip + -- the optimization as it is not critical for correctness. + + if Minimize_Expression_With_Actions then + return False; + end if; + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Expression => Relocate_Node (Expr), + Actions => Actions)); + Analyze_And_Resolve (N, Typ); + + else + Rewrite (N, Relocate_Node (Expr)); + end if; + + -- Note that the result is never static (legitimate cases of + -- static if expressions were folded in Sem_Eval). + + Set_Is_Static_Expression (N, False); + return True; + end Fold_Known_Value; + + begin + if Fold_Known_Value (Cond) then + return; + end if; + end; + end if; + + -- If the type is limited, and the back end does not handle limited + -- types, then we expand as follows to avoid the possibility of + -- improper copying. + + -- type Ptr is access all Typ; + -- Cnn : Ptr; + -- if cond then + -- <<then actions>> + -- Cnn := then-expr'Unrestricted_Access; + -- else + -- <<else actions>> + -- Cnn := else-expr'Unrestricted_Access; + -- end if; + + -- and replace the if expression by a reference to Cnn.all. + + -- This special case can be skipped if the back end handles limited + -- types properly and ensures that no incorrect copies are made. + + if Is_By_Reference_Type (Typ) + and then not Back_End_Handles_Limited_Types + then + -- When the "then" or "else" expressions involve controlled function + -- calls, generated temporaries are chained on the corresponding list + -- of actions. These temporaries need to be finalized after the if + -- expression is evaluated. + + Process_If_Case_Statements (N, Then_Actions (N)); + Process_If_Case_Statements (N, Else_Actions (N)); + + declare + Cnn : constant Entity_Id := Make_Temporary (Loc, 'C', N); + Ptr_Typ : constant Entity_Id := Make_Temporary (Loc, 'A'); + + begin + -- Generate: + -- type Ann is access all Typ; + + Insert_Action (N, + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Ptr_Typ, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Subtype_Indication => New_Occurrence_Of (Typ, Loc)))); + + -- Generate: + -- Cnn : Ann; + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Cnn, + Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc)); + + -- Generate: + -- if Cond then + -- Cnn := <Thenx>'Unrestricted_Access; + -- else + -- Cnn := <Elsex>'Unrestricted_Access; + -- end if; + + New_If := + Make_Implicit_If_Statement (N, + Condition => Relocate_Node (Cond), + Then_Statements => New_List ( + Make_Assignment_Statement (Sloc (Thenx), + Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), + Expression => + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Thenx), + Attribute_Name => Name_Unrestricted_Access))), + + Else_Statements => New_List ( + Make_Assignment_Statement (Sloc (Elsex), + Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), + Expression => + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Elsex), + Attribute_Name => Name_Unrestricted_Access)))); + + -- Preserve the original context for which the if statement is + -- being generated. This is needed by the finalization machinery + -- to prevent the premature finalization of controlled objects + -- found within the if statement. + + Set_From_Conditional_Expression (New_If); + + New_N := + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Cnn, Loc)); + end; + + -- If the result is an unconstrained array and the if expression is in a + -- context other than the initializing expression of the declaration of + -- an object, then we pull out the if expression as follows: + + -- Cnn : constant typ := if-expression + + -- and then replace the if expression with an occurrence of Cnn. This + -- avoids the need in the back end to create on-the-fly variable length + -- temporaries (which it cannot do!) + + -- Note that the test for being in an object declaration avoids doing an + -- unnecessary expansion, and also avoids infinite recursion. + + elsif Is_Array_Type (Typ) and then not Is_Constrained (Typ) + and then (Nkind (Parent (N)) /= N_Object_Declaration + or else Expression (Parent (N)) /= N) + then + declare + Cnn : constant Node_Id := Make_Temporary (Loc, 'C', N); + + begin + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Cnn, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Typ, Loc), + Expression => Relocate_Node (N), + Has_Init_Expression => True)); + + Rewrite (N, New_Occurrence_Of (Cnn, Loc)); + return; + end; + + -- For other types, we only need to expand if there are other actions + -- associated with either branch. + + elsif Present (Then_Actions (N)) or else Present (Else_Actions (N)) then + + -- We now wrap the actions into the appropriate expression + + if Minimize_Expression_With_Actions + and then (Is_Elementary_Type (Underlying_Type (Typ)) + or else Is_Constrained (Underlying_Type (Typ))) + then + -- If we can't use N_Expression_With_Actions nodes, then we insert + -- the following sequence of actions (using Insert_Actions): + + -- Cnn : typ; + -- if cond then + -- <<then actions>> + -- Cnn := then-expr; + -- else + -- <<else actions>> + -- Cnn := else-expr + -- end if; + + -- and replace the if expression by a reference to Cnn + + declare + Cnn : constant Node_Id := Make_Temporary (Loc, 'C', N); + + begin + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Cnn, + Object_Definition => New_Occurrence_Of (Typ, Loc)); + + New_If := + Make_Implicit_If_Statement (N, + Condition => Relocate_Node (Cond), + + Then_Statements => New_List ( + Make_Assignment_Statement (Sloc (Thenx), + Name => New_Occurrence_Of (Cnn, Sloc (Thenx)), + Expression => Relocate_Node (Thenx))), + + Else_Statements => New_List ( + Make_Assignment_Statement (Sloc (Elsex), + Name => New_Occurrence_Of (Cnn, Sloc (Elsex)), + Expression => Relocate_Node (Elsex)))); + + Set_Assignment_OK (Name (First (Then_Statements (New_If)))); + Set_Assignment_OK (Name (First (Else_Statements (New_If)))); + + New_N := New_Occurrence_Of (Cnn, Loc); + end; + + -- Regular path using Expression_With_Actions + + else + if Present (Then_Actions (N)) then + Rewrite (Thenx, + Make_Expression_With_Actions (Sloc (Thenx), + Actions => Then_Actions (N), + Expression => Relocate_Node (Thenx))); + + Set_Then_Actions (N, No_List); + Analyze_And_Resolve (Thenx, Typ); + end if; + + if Present (Else_Actions (N)) then + Rewrite (Elsex, + Make_Expression_With_Actions (Sloc (Elsex), + Actions => Else_Actions (N), + Expression => Relocate_Node (Elsex))); + + Set_Else_Actions (N, No_List); + Analyze_And_Resolve (Elsex, Typ); + end if; + + return; + end if; + + -- If no actions then no expansion needed, gigi will handle it using the + -- same approach as a C conditional expression. + + else + return; + end if; + + -- Fall through here for either the limited expansion, or the case of + -- inserting actions for nonlimited types. In both these cases, we must + -- move the SLOC of the parent If statement to the newly created one and + -- change it to the SLOC of the expression which, after expansion, will + -- correspond to what is being evaluated. + + if Present (Parent (N)) and then Nkind (Parent (N)) = N_If_Statement then + Set_Sloc (New_If, Sloc (Parent (N))); + Set_Sloc (Parent (N), Loc); + end if; + + -- Make sure Then_Actions and Else_Actions are appropriately moved + -- to the new if statement. + + if Present (Then_Actions (N)) then + Insert_List_Before + (First (Then_Statements (New_If)), Then_Actions (N)); + end if; + + if Present (Else_Actions (N)) then + Insert_List_Before + (First (Else_Statements (New_If)), Else_Actions (N)); + end if; + + Insert_Action (N, Decl); + Insert_Action (N, New_If); + Rewrite (N, New_N); + Analyze_And_Resolve (N, Typ); + end Expand_N_If_Expression; + + ----------------- + -- Expand_N_In -- + ----------------- + + procedure Expand_N_In (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Restyp : constant Entity_Id := Etype (N); + Lop : constant Node_Id := Left_Opnd (N); + Rop : constant Node_Id := Right_Opnd (N); + Static : constant Boolean := Is_OK_Static_Expression (N); + + procedure Substitute_Valid_Check; + -- Replaces node N by Lop'Valid. This is done when we have an explicit + -- test for the left operand being in range of its subtype. + + ---------------------------- + -- Substitute_Valid_Check -- + ---------------------------- + + procedure Substitute_Valid_Check is + function Is_OK_Object_Reference (Nod : Node_Id) return Boolean; + -- Determine whether arbitrary node Nod denotes a source object that + -- may safely act as prefix of attribute 'Valid. + + ---------------------------- + -- Is_OK_Object_Reference -- + ---------------------------- + + function Is_OK_Object_Reference (Nod : Node_Id) return Boolean is + Obj_Ref : Node_Id; + + begin + -- Inspect the original operand + + Obj_Ref := Original_Node (Nod); + + -- The object reference must be a source construct, otherwise the + -- codefix suggestion may refer to nonexistent code from a user + -- perspective. + + if Comes_From_Source (Obj_Ref) then + + -- Recover the actual object reference. There may be more cases + -- to consider??? + + loop + if Nkind_In (Obj_Ref, N_Type_Conversion, + N_Unchecked_Type_Conversion) + then + Obj_Ref := Expression (Obj_Ref); + else + exit; + end if; + end loop; + + return Is_Object_Reference (Obj_Ref); + end if; + + return False; + end Is_OK_Object_Reference; + + -- Start of processing for Substitute_Valid_Check + + begin + Rewrite (N, + Make_Attribute_Reference (Loc, + Prefix => Relocate_Node (Lop), + Attribute_Name => Name_Valid)); + + Analyze_And_Resolve (N, Restyp); + + -- Emit a warning when the left-hand operand of the membership test + -- is a source object, otherwise the use of attribute 'Valid would be + -- illegal. The warning is not given when overflow checking is either + -- MINIMIZED or ELIMINATED, as the danger of optimization has been + -- eliminated above. + + if Is_OK_Object_Reference (Lop) + and then Overflow_Check_Mode not in Minimized_Or_Eliminated + then + Error_Msg_N + ("??explicit membership test may be optimized away", N); + Error_Msg_N -- CODEFIX + ("\??use ''Valid attribute instead", N); + end if; + end Substitute_Valid_Check; + + -- Local variables + + Ltyp : Entity_Id; + Rtyp : Entity_Id; + + -- Start of processing for Expand_N_In + + begin + -- If set membership case, expand with separate procedure + + if Present (Alternatives (N)) then + Expand_Set_Membership (N); + return; + end if; + + -- Not set membership, proceed with expansion + + Ltyp := Etype (Left_Opnd (N)); + Rtyp := Etype (Right_Opnd (N)); + + -- If MINIMIZED/ELIMINATED overflow mode and type is a signed integer + -- type, then expand with a separate procedure. Note the use of the + -- flag No_Minimize_Eliminate to prevent infinite recursion. + + if Overflow_Check_Mode in Minimized_Or_Eliminated + and then Is_Signed_Integer_Type (Ltyp) + and then not No_Minimize_Eliminate (N) + then + Expand_Membership_Minimize_Eliminate_Overflow (N); + return; + end if; + + -- Check case of explicit test for an expression in range of its + -- subtype. This is suspicious usage and we replace it with a 'Valid + -- test and give a warning for scalar types. + + if Is_Scalar_Type (Ltyp) + + -- Only relevant for source comparisons + + and then Comes_From_Source (N) + + -- In floating-point this is a standard way to check for finite values + -- and using 'Valid would typically be a pessimization. + + and then not Is_Floating_Point_Type (Ltyp) + + -- Don't give the message unless right operand is a type entity and + -- the type of the left operand matches this type. Note that this + -- eliminates the cases where MINIMIZED/ELIMINATED mode overflow + -- checks have changed the type of the left operand. + + and then Nkind (Rop) in N_Has_Entity + and then Ltyp = Entity (Rop) + + -- Skip this for predicated types, where such expressions are a + -- reasonable way of testing if something meets the predicate. + + and then not Present (Predicate_Function (Ltyp)) + then + Substitute_Valid_Check; + return; + end if; + + -- Do validity check on operands + + if Validity_Checks_On and Validity_Check_Operands then + Ensure_Valid (Left_Opnd (N)); + Validity_Check_Range (Right_Opnd (N)); + end if; + + -- Case of explicit range + + if Nkind (Rop) = N_Range then + declare + Lo : constant Node_Id := Low_Bound (Rop); + Hi : constant Node_Id := High_Bound (Rop); + + Lo_Orig : constant Node_Id := Original_Node (Lo); + Hi_Orig : constant Node_Id := Original_Node (Hi); + + Lcheck : Compare_Result; + Ucheck : Compare_Result; + + Warn1 : constant Boolean := + Constant_Condition_Warnings + and then Comes_From_Source (N) + and then not In_Instance; + -- This must be true for any of the optimization warnings, we + -- clearly want to give them only for source with the flag on. We + -- also skip these warnings in an instance since it may be the + -- case that different instantiations have different ranges. + + Warn2 : constant Boolean := + Warn1 + and then Nkind (Original_Node (Rop)) = N_Range + and then Is_Integer_Type (Etype (Lo)); + -- For the case where only one bound warning is elided, we also + -- insist on an explicit range and an integer type. The reason is + -- that the use of enumeration ranges including an end point is + -- common, as is the use of a subtype name, one of whose bounds is + -- the same as the type of the expression. + + begin + -- If test is explicit x'First .. x'Last, replace by valid check + + -- Could use some individual comments for this complex test ??? + + if Is_Scalar_Type (Ltyp) + + -- And left operand is X'First where X matches left operand + -- type (this eliminates cases of type mismatch, including + -- the cases where ELIMINATED/MINIMIZED mode has changed the + -- type of the left operand. + + and then Nkind (Lo_Orig) = N_Attribute_Reference + and then Attribute_Name (Lo_Orig) = Name_First + and then Nkind (Prefix (Lo_Orig)) in N_Has_Entity + and then Entity (Prefix (Lo_Orig)) = Ltyp + + -- Same tests for right operand + + and then Nkind (Hi_Orig) = N_Attribute_Reference + and then Attribute_Name (Hi_Orig) = Name_Last + and then Nkind (Prefix (Hi_Orig)) in N_Has_Entity + and then Entity (Prefix (Hi_Orig)) = Ltyp + + -- Relevant only for source cases + + and then Comes_From_Source (N) + then + Substitute_Valid_Check; + goto Leave; + end if; + + -- If bounds of type are known at compile time, and the end points + -- are known at compile time and identical, this is another case + -- for substituting a valid test. We only do this for discrete + -- types, since it won't arise in practice for float types. + + if Comes_From_Source (N) + and then Is_Discrete_Type (Ltyp) + and then Compile_Time_Known_Value (Type_High_Bound (Ltyp)) + and then Compile_Time_Known_Value (Type_Low_Bound (Ltyp)) + and then Compile_Time_Known_Value (Lo) + and then Compile_Time_Known_Value (Hi) + and then Expr_Value (Type_High_Bound (Ltyp)) = Expr_Value (Hi) + and then Expr_Value (Type_Low_Bound (Ltyp)) = Expr_Value (Lo) + + -- Kill warnings in instances, since they may be cases where we + -- have a test in the generic that makes sense with some types + -- and not with other types. + + and then not In_Instance + then + Substitute_Valid_Check; + goto Leave; + end if; + + -- If we have an explicit range, do a bit of optimization based on + -- range analysis (we may be able to kill one or both checks). + + Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => False); + Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => False); + + -- If either check is known to fail, replace result by False since + -- the other check does not matter. Preserve the static flag for + -- legality checks, because we are constant-folding beyond RM 4.9. + + if Lcheck = LT or else Ucheck = GT then + if Warn1 then + Error_Msg_N ("?c?range test optimized away", N); + Error_Msg_N ("\?c?value is known to be out of range", N); + end if; + + Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); + Analyze_And_Resolve (N, Restyp); + Set_Is_Static_Expression (N, Static); + goto Leave; + + -- If both checks are known to succeed, replace result by True, + -- since we know we are in range. + + elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then + if Warn1 then + Error_Msg_N ("?c?range test optimized away", N); + Error_Msg_N ("\?c?value is known to be in range", N); + end if; + + Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); + Analyze_And_Resolve (N, Restyp); + Set_Is_Static_Expression (N, Static); + goto Leave; + + -- If lower bound check succeeds and upper bound check is not + -- known to succeed or fail, then replace the range check with + -- a comparison against the upper bound. + + elsif Lcheck in Compare_GE then + if Warn2 and then not In_Instance then + Error_Msg_N ("??lower bound test optimized away", Lo); + Error_Msg_N ("\??value is known to be in range", Lo); + end if; + + Rewrite (N, + Make_Op_Le (Loc, + Left_Opnd => Lop, + Right_Opnd => High_Bound (Rop))); + Analyze_And_Resolve (N, Restyp); + goto Leave; + + -- If upper bound check succeeds and lower bound check is not + -- known to succeed or fail, then replace the range check with + -- a comparison against the lower bound. + + elsif Ucheck in Compare_LE then + if Warn2 and then not In_Instance then + Error_Msg_N ("??upper bound test optimized away", Hi); + Error_Msg_N ("\??value is known to be in range", Hi); + end if; + + Rewrite (N, + Make_Op_Ge (Loc, + Left_Opnd => Lop, + Right_Opnd => Low_Bound (Rop))); + Analyze_And_Resolve (N, Restyp); + goto Leave; + end if; + + -- We couldn't optimize away the range check, but there is one + -- more issue. If we are checking constant conditionals, then we + -- see if we can determine the outcome assuming everything is + -- valid, and if so give an appropriate warning. + + if Warn1 and then not Assume_No_Invalid_Values then + Lcheck := Compile_Time_Compare (Lop, Lo, Assume_Valid => True); + Ucheck := Compile_Time_Compare (Lop, Hi, Assume_Valid => True); + + -- Result is out of range for valid value + + if Lcheck = LT or else Ucheck = GT then + Error_Msg_N + ("?c?value can only be in range if it is invalid", N); + + -- Result is in range for valid value + + elsif Lcheck in Compare_GE and then Ucheck in Compare_LE then + Error_Msg_N + ("?c?value can only be out of range if it is invalid", N); + + -- Lower bound check succeeds if value is valid + + elsif Warn2 and then Lcheck in Compare_GE then + Error_Msg_N + ("?c?lower bound check only fails if it is invalid", Lo); + + -- Upper bound check succeeds if value is valid + + elsif Warn2 and then Ucheck in Compare_LE then + Error_Msg_N + ("?c?upper bound check only fails for invalid values", Hi); + end if; + end if; + end; + + -- For all other cases of an explicit range, nothing to be done + + goto Leave; + + -- Here right operand is a subtype mark + + else + declare + Typ : Entity_Id := Etype (Rop); + Is_Acc : constant Boolean := Is_Access_Type (Typ); + Cond : Node_Id := Empty; + New_N : Node_Id; + Obj : Node_Id := Lop; + SCIL_Node : Node_Id; + + begin + Remove_Side_Effects (Obj); + + -- For tagged type, do tagged membership operation + + if Is_Tagged_Type (Typ) then + + -- No expansion will be performed for VM targets, as the VM + -- back ends will handle the membership tests directly. + + if Tagged_Type_Expansion then + Tagged_Membership (N, SCIL_Node, New_N); + Rewrite (N, New_N); + Analyze_And_Resolve (N, Restyp, Suppress => All_Checks); + + -- Update decoration of relocated node referenced by the + -- SCIL node. + + if Generate_SCIL and then Present (SCIL_Node) then + Set_SCIL_Node (N, SCIL_Node); + end if; + end if; + + goto Leave; + + -- If type is scalar type, rewrite as x in t'First .. t'Last. + -- This reason we do this is that the bounds may have the wrong + -- type if they come from the original type definition. Also this + -- way we get all the processing above for an explicit range. + + -- Don't do this for predicated types, since in this case we + -- want to check the predicate. + + elsif Is_Scalar_Type (Typ) then + if No (Predicate_Function (Typ)) then + Rewrite (Rop, + Make_Range (Loc, + Low_Bound => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_First, + Prefix => New_Occurrence_Of (Typ, Loc)), + + High_Bound => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Last, + Prefix => New_Occurrence_Of (Typ, Loc)))); + Analyze_And_Resolve (N, Restyp); + end if; + + goto Leave; + + -- Ada 2005 (AI-216): Program_Error is raised when evaluating + -- a membership test if the subtype mark denotes a constrained + -- Unchecked_Union subtype and the expression lacks inferable + -- discriminants. + + elsif Is_Unchecked_Union (Base_Type (Typ)) + and then Is_Constrained (Typ) + and then not Has_Inferable_Discriminants (Lop) + then + Insert_Action (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction)); + + -- Prevent Gigi from generating incorrect code by rewriting the + -- test as False. What is this undocumented thing about ??? + + Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); + goto Leave; + end if; + + -- Here we have a non-scalar type + + if Is_Acc then + Typ := Designated_Type (Typ); + end if; + + if not Is_Constrained (Typ) then + Rewrite (N, New_Occurrence_Of (Standard_True, Loc)); + Analyze_And_Resolve (N, Restyp); + + -- For the constrained array case, we have to check the subscripts + -- for an exact match if the lengths are non-zero (the lengths + -- must match in any case). + + elsif Is_Array_Type (Typ) then + Check_Subscripts : declare + function Build_Attribute_Reference + (E : Node_Id; + Nam : Name_Id; + Dim : Nat) return Node_Id; + -- Build attribute reference E'Nam (Dim) + + ------------------------------- + -- Build_Attribute_Reference -- + ------------------------------- + + function Build_Attribute_Reference + (E : Node_Id; + Nam : Name_Id; + Dim : Nat) return Node_Id + is + begin + return + Make_Attribute_Reference (Loc, + Prefix => E, + Attribute_Name => Nam, + Expressions => New_List ( + Make_Integer_Literal (Loc, Dim))); + end Build_Attribute_Reference; + + -- Start of processing for Check_Subscripts + + begin + for J in 1 .. Number_Dimensions (Typ) loop + Evolve_And_Then (Cond, + Make_Op_Eq (Loc, + Left_Opnd => + Build_Attribute_Reference + (Duplicate_Subexpr_No_Checks (Obj), + Name_First, J), + Right_Opnd => + Build_Attribute_Reference + (New_Occurrence_Of (Typ, Loc), Name_First, J))); + + Evolve_And_Then (Cond, + Make_Op_Eq (Loc, + Left_Opnd => + Build_Attribute_Reference + (Duplicate_Subexpr_No_Checks (Obj), + Name_Last, J), + Right_Opnd => + Build_Attribute_Reference + (New_Occurrence_Of (Typ, Loc), Name_Last, J))); + end loop; + + if Is_Acc then + Cond := + Make_Or_Else (Loc, + Left_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => Obj, + Right_Opnd => Make_Null (Loc)), + Right_Opnd => Cond); + end if; + + Rewrite (N, Cond); + Analyze_And_Resolve (N, Restyp); + end Check_Subscripts; + + -- These are the cases where constraint checks may be required, + -- e.g. records with possible discriminants + + else + -- Expand the test into a series of discriminant comparisons. + -- The expression that is built is the negation of the one that + -- is used for checking discriminant constraints. + + Obj := Relocate_Node (Left_Opnd (N)); + + if Has_Discriminants (Typ) then + Cond := Make_Op_Not (Loc, + Right_Opnd => Build_Discriminant_Checks (Obj, Typ)); + + if Is_Acc then + Cond := Make_Or_Else (Loc, + Left_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => Obj, + Right_Opnd => Make_Null (Loc)), + Right_Opnd => Cond); + end if; + + else + Cond := New_Occurrence_Of (Standard_True, Loc); + end if; + + Rewrite (N, Cond); + Analyze_And_Resolve (N, Restyp); + end if; + + -- Ada 2012 (AI05-0149): Handle membership tests applied to an + -- expression of an anonymous access type. This can involve an + -- accessibility test and a tagged type membership test in the + -- case of tagged designated types. + + if Ada_Version >= Ada_2012 + and then Is_Acc + and then Ekind (Ltyp) = E_Anonymous_Access_Type + then + declare + Expr_Entity : Entity_Id := Empty; + New_N : Node_Id; + Param_Level : Node_Id; + Type_Level : Node_Id; + + begin + if Is_Entity_Name (Lop) then + Expr_Entity := Param_Entity (Lop); + + if not Present (Expr_Entity) then + Expr_Entity := Entity (Lop); + end if; + end if; + + -- If a conversion of the anonymous access value to the + -- tested type would be illegal, then the result is False. + + if not Valid_Conversion + (Lop, Rtyp, Lop, Report_Errs => False) + then + Rewrite (N, New_Occurrence_Of (Standard_False, Loc)); + Analyze_And_Resolve (N, Restyp); + + -- Apply an accessibility check if the access object has an + -- associated access level and when the level of the type is + -- less deep than the level of the access parameter. This + -- only occur for access parameters and stand-alone objects + -- of an anonymous access type. + + else + if Present (Expr_Entity) + and then + Present + (Effective_Extra_Accessibility (Expr_Entity)) + and then UI_Gt (Object_Access_Level (Lop), + Type_Access_Level (Rtyp)) + then + Param_Level := + New_Occurrence_Of + (Effective_Extra_Accessibility (Expr_Entity), Loc); + + Type_Level := + Make_Integer_Literal (Loc, Type_Access_Level (Rtyp)); + + -- Return True only if the accessibility level of the + -- expression entity is not deeper than the level of + -- the tested access type. + + Rewrite (N, + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (N), + Right_Opnd => Make_Op_Le (Loc, + Left_Opnd => Param_Level, + Right_Opnd => Type_Level))); + + Analyze_And_Resolve (N); + end if; + + -- If the designated type is tagged, do tagged membership + -- operation. + + -- *** NOTE: we have to check not null before doing the + -- tagged membership test (but maybe that can be done + -- inside Tagged_Membership?). + + if Is_Tagged_Type (Typ) then + Rewrite (N, + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (N), + Right_Opnd => + Make_Op_Ne (Loc, + Left_Opnd => Obj, + Right_Opnd => Make_Null (Loc)))); + + -- No expansion will be performed for VM targets, as + -- the VM back ends will handle the membership tests + -- directly. + + if Tagged_Type_Expansion then + + -- Note that we have to pass Original_Node, because + -- the membership test might already have been + -- rewritten by earlier parts of membership test. + + Tagged_Membership + (Original_Node (N), SCIL_Node, New_N); + + -- Update decoration of relocated node referenced + -- by the SCIL node. + + if Generate_SCIL and then Present (SCIL_Node) then + Set_SCIL_Node (New_N, SCIL_Node); + end if; + + Rewrite (N, + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (N), + Right_Opnd => New_N)); + + Analyze_And_Resolve (N, Restyp); + end if; + end if; + end if; + end; + end if; + end; + end if; + + -- At this point, we have done the processing required for the basic + -- membership test, but not yet dealt with the predicate. + + <<Leave>> + + -- If a predicate is present, then we do the predicate test, but we + -- most certainly want to omit this if we are within the predicate + -- function itself, since otherwise we have an infinite recursion. + -- The check should also not be emitted when testing against a range + -- (the check is only done when the right operand is a subtype; see + -- RM12-4.5.2 (28.1/3-30/3)). + + Predicate_Check : declare + function In_Range_Check return Boolean; + -- Within an expanded range check that may raise Constraint_Error do + -- not generate a predicate check as well. It is redundant because + -- the context will add an explicit predicate check, and it will + -- raise the wrong exception if it fails. + + -------------------- + -- In_Range_Check -- + -------------------- + + function In_Range_Check return Boolean is + P : Node_Id; + begin + P := Parent (N); + while Present (P) loop + if Nkind (P) = N_Raise_Constraint_Error then + return True; + + elsif Nkind (P) in N_Statement_Other_Than_Procedure_Call + or else Nkind (P) = N_Procedure_Call_Statement + or else Nkind (P) in N_Declaration + then + return False; + end if; + + P := Parent (P); + end loop; + + return False; + end In_Range_Check; + + -- Local variables + + PFunc : constant Entity_Id := Predicate_Function (Rtyp); + R_Op : Node_Id; + + -- Start of processing for Predicate_Check + + begin + if Present (PFunc) + and then Current_Scope /= PFunc + and then Nkind (Rop) /= N_Range + then + if not In_Range_Check then + R_Op := Make_Predicate_Call (Rtyp, Lop, Mem => True); + else + R_Op := New_Occurrence_Of (Standard_True, Loc); + end if; + + Rewrite (N, + Make_And_Then (Loc, + Left_Opnd => Relocate_Node (N), + Right_Opnd => R_Op)); + + -- Analyze new expression, mark left operand as analyzed to + -- avoid infinite recursion adding predicate calls. Similarly, + -- suppress further range checks on the call. + + Set_Analyzed (Left_Opnd (N)); + Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); + + -- All done, skip attempt at compile time determination of result + + return; + end if; + end Predicate_Check; + end Expand_N_In; + + -------------------------------- + -- Expand_N_Indexed_Component -- + -------------------------------- + + procedure Expand_N_Indexed_Component (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + P : constant Node_Id := Prefix (N); + T : constant Entity_Id := Etype (P); + Atp : Entity_Id; + + begin + -- A special optimization, if we have an indexed component that is + -- selecting from a slice, then we can eliminate the slice, since, for + -- example, x (i .. j)(k) is identical to x(k). The only difference is + -- the range check required by the slice. The range check for the slice + -- itself has already been generated. The range check for the + -- subscripting operation is ensured by converting the subject to + -- the subtype of the slice. + + -- This optimization not only generates better code, avoiding slice + -- messing especially in the packed case, but more importantly bypasses + -- some problems in handling this peculiar case, for example, the issue + -- of dealing specially with object renamings. + + if Nkind (P) = N_Slice + + -- This optimization is disabled for CodePeer because it can transform + -- an index-check constraint_error into a range-check constraint_error + -- and CodePeer cares about that distinction. + + and then not CodePeer_Mode + then + Rewrite (N, + Make_Indexed_Component (Loc, + Prefix => Prefix (P), + Expressions => New_List ( + Convert_To + (Etype (First_Index (Etype (P))), + First (Expressions (N)))))); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place + -- function, then additional actuals must be passed. + + if Is_Build_In_Place_Function_Call (P) then + Make_Build_In_Place_Call_In_Anonymous_Context (P); + + -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix + -- containing build-in-place function calls whose returned object covers + -- interface types. + + elsif Present (Unqual_BIP_Iface_Function_Call (P)) then + Make_Build_In_Place_Iface_Call_In_Anonymous_Context (P); + end if; + + -- If the prefix is an access type, then we unconditionally rewrite if + -- as an explicit dereference. This simplifies processing for several + -- cases, including packed array cases and certain cases in which checks + -- must be generated. We used to try to do this only when it was + -- necessary, but it cleans up the code to do it all the time. + + if Is_Access_Type (T) then + Insert_Explicit_Dereference (P); + Analyze_And_Resolve (P, Designated_Type (T)); + Atp := Designated_Type (T); + else + Atp := T; + end if; + + -- Generate index and validity checks + + Generate_Index_Checks (N); + + if Validity_Checks_On and then Validity_Check_Subscripts then + Apply_Subscript_Validity_Checks (N); + end if; + + -- If selecting from an array with atomic components, and atomic sync + -- is not suppressed for this array type, set atomic sync flag. + + if (Has_Atomic_Components (Atp) + and then not Atomic_Synchronization_Disabled (Atp)) + or else (Is_Atomic (Typ) + and then not Atomic_Synchronization_Disabled (Typ)) + or else (Is_Entity_Name (P) + and then Has_Atomic_Components (Entity (P)) + and then not Atomic_Synchronization_Disabled (Entity (P))) + then + Activate_Atomic_Synchronization (N); + end if; + + -- All done if the prefix is not a packed array implemented specially + + if not (Is_Packed (Etype (Prefix (N))) + and then Present (Packed_Array_Impl_Type (Etype (Prefix (N))))) + then + return; + end if; + + -- For packed arrays that are not bit-packed (i.e. the case of an array + -- with one or more index types with a non-contiguous enumeration type), + -- we can always use the normal packed element get circuit. + + if not Is_Bit_Packed_Array (Etype (Prefix (N))) then + Expand_Packed_Element_Reference (N); + return; + end if; + + -- For a reference to a component of a bit packed array, we convert it + -- to a reference to the corresponding Packed_Array_Impl_Type. We only + -- want to do this for simple references, and not for: + + -- Left side of assignment, or prefix of left side of assignment, or + -- prefix of the prefix, to handle packed arrays of packed arrays, + -- This case is handled in Exp_Ch5.Expand_N_Assignment_Statement + + -- Renaming objects in renaming associations + -- This case is handled when a use of the renamed variable occurs + + -- Actual parameters for a procedure call + -- This case is handled in Exp_Ch6.Expand_Actuals + + -- The second expression in a 'Read attribute reference + + -- The prefix of an address or bit or size attribute reference + + -- The following circuit detects these exceptions. Note that we need to + -- deal with implicit dereferences when climbing up the parent chain, + -- with the additional difficulty that the type of parents may have yet + -- to be resolved since prefixes are usually resolved first. + + declare + Child : Node_Id := N; + Parnt : Node_Id := Parent (N); + + begin + loop + if Nkind (Parnt) = N_Unchecked_Expression then + null; + + elsif Nkind_In (Parnt, N_Object_Renaming_Declaration, + N_Procedure_Call_Statement) + or else (Nkind (Parnt) = N_Parameter_Association + and then + Nkind (Parent (Parnt)) = N_Procedure_Call_Statement) + then + return; + + elsif Nkind (Parnt) = N_Attribute_Reference + and then Nam_In (Attribute_Name (Parnt), Name_Address, + Name_Bit, + Name_Size) + and then Prefix (Parnt) = Child + then + return; + + elsif Nkind (Parnt) = N_Assignment_Statement + and then Name (Parnt) = Child + then + return; + + -- If the expression is an index of an indexed component, it must + -- be expanded regardless of context. + + elsif Nkind (Parnt) = N_Indexed_Component + and then Child /= Prefix (Parnt) + then + Expand_Packed_Element_Reference (N); + return; + + elsif Nkind (Parent (Parnt)) = N_Assignment_Statement + and then Name (Parent (Parnt)) = Parnt + then + return; + + elsif Nkind (Parnt) = N_Attribute_Reference + and then Attribute_Name (Parnt) = Name_Read + and then Next (First (Expressions (Parnt))) = Child + then + return; + + elsif Nkind (Parnt) = N_Indexed_Component + and then Prefix (Parnt) = Child + then + null; + + elsif Nkind (Parnt) = N_Selected_Component + and then Prefix (Parnt) = Child + and then not (Present (Etype (Selector_Name (Parnt))) + and then + Is_Access_Type (Etype (Selector_Name (Parnt)))) + then + null; + + -- If the parent is a dereference, either implicit or explicit, + -- then the packed reference needs to be expanded. + + else + Expand_Packed_Element_Reference (N); + return; + end if; + + -- Keep looking up tree for unchecked expression, or if we are the + -- prefix of a possible assignment left side. + + Child := Parnt; + Parnt := Parent (Child); + end loop; + end; + end Expand_N_Indexed_Component; + + --------------------- + -- Expand_N_Not_In -- + --------------------- + + -- Replace a not in b by not (a in b) so that the expansions for (a in b) + -- can be done. This avoids needing to duplicate this expansion code. + + procedure Expand_N_Not_In (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Cfs : constant Boolean := Comes_From_Source (N); + + begin + Rewrite (N, + Make_Op_Not (Loc, + Right_Opnd => + Make_In (Loc, + Left_Opnd => Left_Opnd (N), + Right_Opnd => Right_Opnd (N)))); + + -- If this is a set membership, preserve list of alternatives + + Set_Alternatives (Right_Opnd (N), Alternatives (Original_Node (N))); + + -- We want this to appear as coming from source if original does (see + -- transformations in Expand_N_In). + + Set_Comes_From_Source (N, Cfs); + Set_Comes_From_Source (Right_Opnd (N), Cfs); + + -- Now analyze transformed node + + Analyze_And_Resolve (N, Typ); + end Expand_N_Not_In; + + ------------------- + -- Expand_N_Null -- + ------------------- + + -- The only replacement required is for the case of a null of a type that + -- is an access to protected subprogram, or a subtype thereof. We represent + -- such access values as a record, and so we must replace the occurrence of + -- null by the equivalent record (with a null address and a null pointer in + -- it), so that the back end creates the proper value. + + procedure Expand_N_Null (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Base_Type (Etype (N)); + Agg : Node_Id; + + begin + if Is_Access_Protected_Subprogram_Type (Typ) then + Agg := + Make_Aggregate (Loc, + Expressions => New_List ( + New_Occurrence_Of (RTE (RE_Null_Address), Loc), + Make_Null (Loc))); + + Rewrite (N, Agg); + Analyze_And_Resolve (N, Equivalent_Type (Typ)); + + -- For subsequent semantic analysis, the node must retain its type. + -- Gigi in any case replaces this type by the corresponding record + -- type before processing the node. + + Set_Etype (N, Typ); + end if; + + exception + when RE_Not_Available => + return; + end Expand_N_Null; + + --------------------- + -- Expand_N_Op_Abs -- + --------------------- + + procedure Expand_N_Op_Abs (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Expr : constant Node_Id := Right_Opnd (N); + + begin + Unary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Deal with software overflow checking + + if not Backend_Overflow_Checks_On_Target + and then Is_Signed_Integer_Type (Etype (N)) + and then Do_Overflow_Check (N) + then + -- The only case to worry about is when the argument is equal to the + -- largest negative number, so what we do is to insert the check: + + -- [constraint_error when Expr = typ'Base'First] + + -- with the usual Duplicate_Subexpr use coding for expr + + Insert_Action (N, + Make_Raise_Constraint_Error (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => Duplicate_Subexpr (Expr), + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (Base_Type (Etype (Expr)), Loc), + Attribute_Name => Name_First)), + Reason => CE_Overflow_Check_Failed)); + end if; + end Expand_N_Op_Abs; + + --------------------- + -- Expand_N_Op_Add -- + --------------------- + + procedure Expand_N_Op_Add (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- N + 0 = 0 + N = N for integer types + + if Is_Integer_Type (Typ) then + if Compile_Time_Known_Value (Right_Opnd (N)) + and then Expr_Value (Right_Opnd (N)) = Uint_0 + then + Rewrite (N, Left_Opnd (N)); + return; + + elsif Compile_Time_Known_Value (Left_Opnd (N)) + and then Expr_Value (Left_Opnd (N)) = Uint_0 + then + Rewrite (N, Right_Opnd (N)); + return; + end if; + end if; + + -- Arithmetic overflow checks for signed integer/fixed point types + + if Is_Signed_Integer_Type (Typ) or else Is_Fixed_Point_Type (Typ) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Overflow checks for floating-point if -gnateF mode active + + Check_Float_Op_Overflow (N); + + -- When generating C code, convert nonbinary modular additions into code + -- that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Add; + + --------------------- + -- Expand_N_Op_And -- + --------------------- + + procedure Expand_N_Op_And (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + if Is_Array_Type (Etype (N)) then + Expand_Boolean_Operator (N); + + elsif Is_Boolean_Type (Etype (N)) then + Adjust_Condition (Left_Opnd (N)); + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + + elsif Is_Intrinsic_Subprogram (Entity (N)) then + Expand_Intrinsic_Call (N, Entity (N)); + end if; + + -- When generating C code, convert nonbinary modular operators into code + -- that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_And; + + ------------------------ + -- Expand_N_Op_Concat -- + ------------------------ + + procedure Expand_N_Op_Concat (N : Node_Id) is + Opnds : List_Id; + -- List of operands to be concatenated + + Cnode : Node_Id; + -- Node which is to be replaced by the result of concatenating the nodes + -- in the list Opnds. + + begin + -- Ensure validity of both operands + + Binary_Op_Validity_Checks (N); + + -- If we are the left operand of a concatenation higher up the tree, + -- then do nothing for now, since we want to deal with a series of + -- concatenations as a unit. + + if Nkind (Parent (N)) = N_Op_Concat + and then N = Left_Opnd (Parent (N)) + then + return; + end if; + + -- We get here with a concatenation whose left operand may be a + -- concatenation itself with a consistent type. We need to process + -- these concatenation operands from left to right, which means + -- from the deepest node in the tree to the highest node. + + Cnode := N; + while Nkind (Left_Opnd (Cnode)) = N_Op_Concat loop + Cnode := Left_Opnd (Cnode); + end loop; + + -- Now Cnode is the deepest concatenation, and its parents are the + -- concatenation nodes above, so now we process bottom up, doing the + -- operands. + + -- The outer loop runs more than once if more than one concatenation + -- type is involved. + + Outer : loop + Opnds := New_List (Left_Opnd (Cnode), Right_Opnd (Cnode)); + Set_Parent (Opnds, N); + + -- The inner loop gathers concatenation operands + + Inner : while Cnode /= N + and then Base_Type (Etype (Cnode)) = + Base_Type (Etype (Parent (Cnode))) + loop + Cnode := Parent (Cnode); + Append (Right_Opnd (Cnode), Opnds); + end loop Inner; + + -- Note: The following code is a temporary workaround for N731-034 + -- and N829-028 and will be kept until the general issue of internal + -- symbol serialization is addressed. The workaround is kept under a + -- debug switch to avoid permiating into the general case. + + -- Wrap the node to concatenate into an expression actions node to + -- keep it nicely packaged. This is useful in the case of an assert + -- pragma with a concatenation where we want to be able to delete + -- the concatenation and all its expansion stuff. + + if Debug_Flag_Dot_H then + declare + Cnod : constant Node_Id := New_Copy_Tree (Cnode); + Typ : constant Entity_Id := Base_Type (Etype (Cnode)); + + begin + -- Note: use Rewrite rather than Replace here, so that for + -- example Why_Not_Static can find the original concatenation + -- node OK! + + Rewrite (Cnode, + Make_Expression_With_Actions (Sloc (Cnode), + Actions => New_List (Make_Null_Statement (Sloc (Cnode))), + Expression => Cnod)); + + Expand_Concatenate (Cnod, Opnds); + Analyze_And_Resolve (Cnode, Typ); + end; + + -- Default case + + else + Expand_Concatenate (Cnode, Opnds); + end if; + + exit Outer when Cnode = N; + Cnode := Parent (Cnode); + end loop Outer; + end Expand_N_Op_Concat; + + ------------------------ + -- Expand_N_Op_Divide -- + ------------------------ + + procedure Expand_N_Op_Divide (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Lopnd : constant Node_Id := Left_Opnd (N); + Ropnd : constant Node_Id := Right_Opnd (N); + Ltyp : constant Entity_Id := Etype (Lopnd); + Rtyp : constant Entity_Id := Etype (Ropnd); + Typ : Entity_Id := Etype (N); + Rknow : constant Boolean := Is_Integer_Type (Typ) + and then + Compile_Time_Known_Value (Ropnd); + Rval : Uint; + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Otherwise proceed with expansion of division + + if Rknow then + Rval := Expr_Value (Ropnd); + end if; + + -- N / 1 = N for integer types + + if Rknow and then Rval = Uint_1 then + Rewrite (N, Lopnd); + return; + end if; + + -- Convert x / 2 ** y to Shift_Right (x, y). Note that the fact that + -- Is_Power_Of_2_For_Shift is set means that we know that our left + -- operand is an unsigned integer, as required for this to work. + + if Nkind (Ropnd) = N_Op_Expon + and then Is_Power_Of_2_For_Shift (Ropnd) + + -- We cannot do this transformation in configurable run time mode if we + -- have 64-bit integers and long shifts are not available. + + and then (Esize (Ltyp) <= 32 or else Support_Long_Shifts_On_Target) + then + Rewrite (N, + Make_Op_Shift_Right (Loc, + Left_Opnd => Lopnd, + Right_Opnd => + Convert_To (Standard_Natural, Right_Opnd (Ropnd)))); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Do required fixup of universal fixed operation + + if Typ = Universal_Fixed then + Fixup_Universal_Fixed_Operation (N); + Typ := Etype (N); + end if; + + -- Divisions with fixed-point results + + if Is_Fixed_Point_Type (Typ) then + + -- No special processing if Treat_Fixed_As_Integer is set, since + -- from a semantic point of view such operations are simply integer + -- operations and will be treated that way. + + if not Treat_Fixed_As_Integer (N) then + if Is_Integer_Type (Rtyp) then + Expand_Divide_Fixed_By_Integer_Giving_Fixed (N); + else + Expand_Divide_Fixed_By_Fixed_Giving_Fixed (N); + end if; + end if; + + -- Deal with divide-by-zero check if back end cannot handle them + -- and the flag is set indicating that we need such a check. Note + -- that we don't need to bother here with the case of mixed-mode + -- (Right operand an integer type), since these will be rewritten + -- with conversions to a divide with a fixed-point right operand. + + if Nkind (N) = N_Op_Divide + and then Do_Division_Check (N) + and then not Backend_Divide_Checks_On_Target + and then not Is_Integer_Type (Rtyp) + then + Set_Do_Division_Check (N, False); + Insert_Action (N, + Make_Raise_Constraint_Error (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => Duplicate_Subexpr_Move_Checks (Ropnd), + Right_Opnd => Make_Real_Literal (Loc, Ureal_0)), + Reason => CE_Divide_By_Zero)); + end if; + + -- Other cases of division of fixed-point operands. Again we exclude the + -- case where Treat_Fixed_As_Integer is set. + + elsif (Is_Fixed_Point_Type (Ltyp) or else Is_Fixed_Point_Type (Rtyp)) + and then not Treat_Fixed_As_Integer (N) + then + if Is_Integer_Type (Typ) then + Expand_Divide_Fixed_By_Fixed_Giving_Integer (N); + else + pragma Assert (Is_Floating_Point_Type (Typ)); + Expand_Divide_Fixed_By_Fixed_Giving_Float (N); + end if; + + -- Mixed-mode operations can appear in a non-static universal context, + -- in which case the integer argument must be converted explicitly. + + elsif Typ = Universal_Real and then Is_Integer_Type (Rtyp) then + Rewrite (Ropnd, + Convert_To (Universal_Real, Relocate_Node (Ropnd))); + + Analyze_And_Resolve (Ropnd, Universal_Real); + + elsif Typ = Universal_Real and then Is_Integer_Type (Ltyp) then + Rewrite (Lopnd, + Convert_To (Universal_Real, Relocate_Node (Lopnd))); + + Analyze_And_Resolve (Lopnd, Universal_Real); + + -- Non-fixed point cases, do integer zero divide and overflow checks + + elsif Is_Integer_Type (Typ) then + Apply_Divide_Checks (N); + end if; + + -- Overflow checks for floating-point if -gnateF mode active + + Check_Float_Op_Overflow (N); + + -- When generating C code, convert nonbinary modular divisions into code + -- that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Divide; + + -------------------- + -- Expand_N_Op_Eq -- + -------------------- + + procedure Expand_N_Op_Eq (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Lhs : constant Node_Id := Left_Opnd (N); + Rhs : constant Node_Id := Right_Opnd (N); + Bodies : constant List_Id := New_List; + A_Typ : constant Entity_Id := Etype (Lhs); + + Typl : Entity_Id := A_Typ; + Op_Name : Entity_Id; + Prim : Elmt_Id; + + procedure Build_Equality_Call (Eq : Entity_Id); + -- If a constructed equality exists for the type or for its parent, + -- build and analyze call, adding conversions if the operation is + -- inherited. + + function Has_Unconstrained_UU_Component (Typ : Node_Id) return Boolean; + -- Determines whether a type has a subcomponent of an unconstrained + -- Unchecked_Union subtype. Typ is a record type. + + ------------------------- + -- Build_Equality_Call -- + ------------------------- + + procedure Build_Equality_Call (Eq : Entity_Id) is + Op_Type : constant Entity_Id := Etype (First_Formal (Eq)); + L_Exp : Node_Id := Relocate_Node (Lhs); + R_Exp : Node_Id := Relocate_Node (Rhs); + + begin + -- Adjust operands if necessary to comparison type + + if Base_Type (Op_Type) /= Base_Type (A_Typ) + and then not Is_Class_Wide_Type (A_Typ) + then + L_Exp := OK_Convert_To (Op_Type, L_Exp); + R_Exp := OK_Convert_To (Op_Type, R_Exp); + end if; + + -- If we have an Unchecked_Union, we need to add the inferred + -- discriminant values as actuals in the function call. At this + -- point, the expansion has determined that both operands have + -- inferable discriminants. + + if Is_Unchecked_Union (Op_Type) then + declare + Lhs_Type : constant Node_Id := Etype (L_Exp); + Rhs_Type : constant Node_Id := Etype (R_Exp); + + Lhs_Discr_Vals : Elist_Id; + -- List of inferred discriminant values for left operand. + + Rhs_Discr_Vals : Elist_Id; + -- List of inferred discriminant values for right operand. + + Discr : Entity_Id; + + begin + Lhs_Discr_Vals := New_Elmt_List; + Rhs_Discr_Vals := New_Elmt_List; + + -- Per-object constrained selected components require special + -- attention. If the enclosing scope of the component is an + -- Unchecked_Union, we cannot reference its discriminants + -- directly. This is why we use the extra parameters of the + -- equality function of the enclosing Unchecked_Union. + + -- type UU_Type (Discr : Integer := 0) is + -- . . . + -- end record; + -- pragma Unchecked_Union (UU_Type); + + -- 1. Unchecked_Union enclosing record: + + -- type Enclosing_UU_Type (Discr : Integer := 0) is record + -- . . . + -- Comp : UU_Type (Discr); + -- . . . + -- end Enclosing_UU_Type; + -- pragma Unchecked_Union (Enclosing_UU_Type); + + -- Obj1 : Enclosing_UU_Type; + -- Obj2 : Enclosing_UU_Type (1); + + -- [. . .] Obj1 = Obj2 [. . .] + + -- Generated code: + + -- if not (uu_typeEQ (obj1.comp, obj2.comp, a, b)) then + + -- A and B are the formal parameters of the equality function + -- of Enclosing_UU_Type. The function always has two extra + -- formals to capture the inferred discriminant values for + -- each discriminant of the type. + + -- 2. Non-Unchecked_Union enclosing record: + + -- type + -- Enclosing_Non_UU_Type (Discr : Integer := 0) + -- is record + -- . . . + -- Comp : UU_Type (Discr); + -- . . . + -- end Enclosing_Non_UU_Type; + + -- Obj1 : Enclosing_Non_UU_Type; + -- Obj2 : Enclosing_Non_UU_Type (1); + + -- ... Obj1 = Obj2 ... + + -- Generated code: + + -- if not (uu_typeEQ (obj1.comp, obj2.comp, + -- obj1.discr, obj2.discr)) then + + -- In this case we can directly reference the discriminants of + -- the enclosing record. + + -- Process left operand of equality + + if Nkind (Lhs) = N_Selected_Component + and then + Has_Per_Object_Constraint (Entity (Selector_Name (Lhs))) + then + -- If enclosing record is an Unchecked_Union, use formals + -- corresponding to each discriminant. The name of the + -- formal is that of the discriminant, with added suffix, + -- see Exp_Ch3.Build_Record_Equality for details. + + if Is_Unchecked_Union (Scope (Entity (Selector_Name (Lhs)))) + then + Discr := + First_Discriminant + (Scope (Entity (Selector_Name (Lhs)))); + while Present (Discr) loop + Append_Elmt + (Make_Identifier (Loc, + Chars => New_External_Name (Chars (Discr), 'A')), + To => Lhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + + -- If enclosing record is of a non-Unchecked_Union type, it + -- is possible to reference its discriminants directly. + + else + Discr := First_Discriminant (Lhs_Type); + while Present (Discr) loop + Append_Elmt + (Make_Selected_Component (Loc, + Prefix => Prefix (Lhs), + Selector_Name => + New_Copy + (Get_Discriminant_Value (Discr, + Lhs_Type, + Stored_Constraint (Lhs_Type)))), + To => Lhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + end if; + + -- Otherwise operand is on object with a constrained type. + -- Infer the discriminant values from the constraint. + + else + + Discr := First_Discriminant (Lhs_Type); + while Present (Discr) loop + Append_Elmt + (New_Copy + (Get_Discriminant_Value (Discr, + Lhs_Type, + Stored_Constraint (Lhs_Type))), + To => Lhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + end if; + + -- Similar processing for right operand of equality + + if Nkind (Rhs) = N_Selected_Component + and then + Has_Per_Object_Constraint (Entity (Selector_Name (Rhs))) + then + if Is_Unchecked_Union + (Scope (Entity (Selector_Name (Rhs)))) + then + Discr := + First_Discriminant + (Scope (Entity (Selector_Name (Rhs)))); + while Present (Discr) loop + Append_Elmt + (Make_Identifier (Loc, + Chars => New_External_Name (Chars (Discr), 'B')), + To => Rhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + + else + Discr := First_Discriminant (Rhs_Type); + while Present (Discr) loop + Append_Elmt + (Make_Selected_Component (Loc, + Prefix => Prefix (Rhs), + Selector_Name => + New_Copy (Get_Discriminant_Value + (Discr, + Rhs_Type, + Stored_Constraint (Rhs_Type)))), + To => Rhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + end if; + + else + Discr := First_Discriminant (Rhs_Type); + while Present (Discr) loop + Append_Elmt + (New_Copy (Get_Discriminant_Value + (Discr, + Rhs_Type, + Stored_Constraint (Rhs_Type))), + To => Rhs_Discr_Vals); + Next_Discriminant (Discr); + end loop; + end if; + + -- Now merge the list of discriminant values so that values + -- of corresponding discriminants are adjacent. + + declare + Params : List_Id; + L_Elmt : Elmt_Id; + R_Elmt : Elmt_Id; + + begin + Params := New_List (L_Exp, R_Exp); + L_Elmt := First_Elmt (Lhs_Discr_Vals); + R_Elmt := First_Elmt (Rhs_Discr_Vals); + while Present (L_Elmt) loop + Append_To (Params, Node (L_Elmt)); + Append_To (Params, Node (R_Elmt)); + Next_Elmt (L_Elmt); + Next_Elmt (R_Elmt); + end loop; + + Rewrite (N, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Eq, Loc), + Parameter_Associations => Params)); + end; + end; + + -- Normal case, not an unchecked union + + else + Rewrite (N, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Eq, Loc), + Parameter_Associations => New_List (L_Exp, R_Exp))); + end if; + + Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); + end Build_Equality_Call; + + ------------------------------------ + -- Has_Unconstrained_UU_Component -- + ------------------------------------ + + function Has_Unconstrained_UU_Component + (Typ : Node_Id) return Boolean + is + Tdef : constant Node_Id := + Type_Definition (Declaration_Node (Base_Type (Typ))); + Clist : Node_Id; + Vpart : Node_Id; + + function Component_Is_Unconstrained_UU + (Comp : Node_Id) return Boolean; + -- Determines whether the subtype of the component is an + -- unconstrained Unchecked_Union. + + function Variant_Is_Unconstrained_UU + (Variant : Node_Id) return Boolean; + -- Determines whether a component of the variant has an unconstrained + -- Unchecked_Union subtype. + + ----------------------------------- + -- Component_Is_Unconstrained_UU -- + ----------------------------------- + + function Component_Is_Unconstrained_UU + (Comp : Node_Id) return Boolean + is + begin + if Nkind (Comp) /= N_Component_Declaration then + return False; + end if; + + declare + Sindic : constant Node_Id := + Subtype_Indication (Component_Definition (Comp)); + + begin + -- Unconstrained nominal type. In the case of a constraint + -- present, the node kind would have been N_Subtype_Indication. + + if Nkind (Sindic) = N_Identifier then + return Is_Unchecked_Union (Base_Type (Etype (Sindic))); + end if; + + return False; + end; + end Component_Is_Unconstrained_UU; + + --------------------------------- + -- Variant_Is_Unconstrained_UU -- + --------------------------------- + + function Variant_Is_Unconstrained_UU + (Variant : Node_Id) return Boolean + is + Clist : constant Node_Id := Component_List (Variant); + + begin + if Is_Empty_List (Component_Items (Clist)) then + return False; + end if; + + -- We only need to test one component + + declare + Comp : Node_Id := First (Component_Items (Clist)); + + begin + while Present (Comp) loop + if Component_Is_Unconstrained_UU (Comp) then + return True; + end if; + + Next (Comp); + end loop; + end; + + -- None of the components withing the variant were of + -- unconstrained Unchecked_Union type. + + return False; + end Variant_Is_Unconstrained_UU; + + -- Start of processing for Has_Unconstrained_UU_Component + + begin + if Null_Present (Tdef) then + return False; + end if; + + Clist := Component_List (Tdef); + Vpart := Variant_Part (Clist); + + -- Inspect available components + + if Present (Component_Items (Clist)) then + declare + Comp : Node_Id := First (Component_Items (Clist)); + + begin + while Present (Comp) loop + + -- One component is sufficient + + if Component_Is_Unconstrained_UU (Comp) then + return True; + end if; + + Next (Comp); + end loop; + end; + end if; + + -- Inspect available components withing variants + + if Present (Vpart) then + declare + Variant : Node_Id := First (Variants (Vpart)); + + begin + while Present (Variant) loop + + -- One component within a variant is sufficient + + if Variant_Is_Unconstrained_UU (Variant) then + return True; + end if; + + Next (Variant); + end loop; + end; + end if; + + -- Neither the available components, nor the components inside the + -- variant parts were of an unconstrained Unchecked_Union subtype. + + return False; + end Has_Unconstrained_UU_Component; + + -- Start of processing for Expand_N_Op_Eq + + begin + Binary_Op_Validity_Checks (N); + + -- Deal with private types + + if Ekind (Typl) = E_Private_Type then + Typl := Underlying_Type (Typl); + elsif Ekind (Typl) = E_Private_Subtype then + Typl := Underlying_Type (Base_Type (Typl)); + else + null; + end if; + + -- It may happen in error situations that the underlying type is not + -- set. The error will be detected later, here we just defend the + -- expander code. + + if No (Typl) then + return; + end if; + + -- Now get the implementation base type (note that plain Base_Type here + -- might lead us back to the private type, which is not what we want!) + + Typl := Implementation_Base_Type (Typl); + + -- Equality between variant records results in a call to a routine + -- that has conditional tests of the discriminant value(s), and hence + -- violates the No_Implicit_Conditionals restriction. + + if Has_Variant_Part (Typl) then + declare + Msg : Boolean; + + begin + Check_Restriction (Msg, No_Implicit_Conditionals, N); + + if Msg then + Error_Msg_N + ("\comparison of variant records tests discriminants", N); + return; + end if; + end; + end if; + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that + -- means we no longer have a comparison operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Eq then + return; + end if; + + -- Boolean types (requiring handling of non-standard case) + + if Is_Boolean_Type (Typl) then + Adjust_Condition (Left_Opnd (N)); + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + + -- Array types + + elsif Is_Array_Type (Typl) then + + -- If we are doing full validity checking, and it is possible for the + -- array elements to be invalid then expand out array comparisons to + -- make sure that we check the array elements. + + if Validity_Check_Operands + and then not Is_Known_Valid (Component_Type (Typl)) + then + declare + Save_Force_Validity_Checks : constant Boolean := + Force_Validity_Checks; + begin + Force_Validity_Checks := True; + Rewrite (N, + Expand_Array_Equality + (N, + Relocate_Node (Lhs), + Relocate_Node (Rhs), + Bodies, + Typl)); + Insert_Actions (N, Bodies); + Analyze_And_Resolve (N, Standard_Boolean); + Force_Validity_Checks := Save_Force_Validity_Checks; + end; + + -- Packed case where both operands are known aligned + + elsif Is_Bit_Packed_Array (Typl) + and then not Is_Possibly_Unaligned_Object (Lhs) + and then not Is_Possibly_Unaligned_Object (Rhs) + then + Expand_Packed_Eq (N); + + -- Where the component type is elementary we can use a block bit + -- comparison (if supported on the target) exception in the case + -- of floating-point (negative zero issues require element by + -- element comparison), and atomic/VFA types (where we must be sure + -- to load elements independently) and possibly unaligned arrays. + + elsif Is_Elementary_Type (Component_Type (Typl)) + and then not Is_Floating_Point_Type (Component_Type (Typl)) + and then not Is_Atomic_Or_VFA (Component_Type (Typl)) + and then not Is_Possibly_Unaligned_Object (Lhs) + and then not Is_Possibly_Unaligned_Object (Rhs) + and then Support_Composite_Compare_On_Target + then + null; + + -- For composite and floating-point cases, expand equality loop to + -- make sure of using proper comparisons for tagged types, and + -- correctly handling the floating-point case. + + else + Rewrite (N, + Expand_Array_Equality + (N, + Relocate_Node (Lhs), + Relocate_Node (Rhs), + Bodies, + Typl)); + Insert_Actions (N, Bodies, Suppress => All_Checks); + Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); + end if; + + -- Record Types + + elsif Is_Record_Type (Typl) then + + -- For tagged types, use the primitive "=" + + if Is_Tagged_Type (Typl) then + + -- No need to do anything else compiling under restriction + -- No_Dispatching_Calls. During the semantic analysis we + -- already notified such violation. + + if Restriction_Active (No_Dispatching_Calls) then + return; + end if; + + -- If this is derived from an untagged private type completed with + -- a tagged type, it does not have a full view, so we use the + -- primitive operations of the private type. This check should no + -- longer be necessary when these types get their full views??? + + if Is_Private_Type (A_Typ) + and then not Is_Tagged_Type (A_Typ) + and then Is_Derived_Type (A_Typ) + and then No (Full_View (A_Typ)) + then + -- Search for equality operation, checking that the operands + -- have the same type. Note that we must find a matching entry, + -- or something is very wrong. + + Prim := First_Elmt (Collect_Primitive_Operations (A_Typ)); + + while Present (Prim) loop + exit when Chars (Node (Prim)) = Name_Op_Eq + and then Etype (First_Formal (Node (Prim))) = + Etype (Next_Formal (First_Formal (Node (Prim)))) + and then + Base_Type (Etype (Node (Prim))) = Standard_Boolean; + + Next_Elmt (Prim); + end loop; + + pragma Assert (Present (Prim)); + Op_Name := Node (Prim); + + -- Find the type's predefined equality or an overriding + -- user-defined equality. The reason for not simply calling + -- Find_Prim_Op here is that there may be a user-defined + -- overloaded equality op that precedes the equality that we + -- want, so we have to explicitly search (e.g., there could be + -- an equality with two different parameter types). + + else + if Is_Class_Wide_Type (Typl) then + Typl := Find_Specific_Type (Typl); + end if; + + Prim := First_Elmt (Primitive_Operations (Typl)); + while Present (Prim) loop + exit when Chars (Node (Prim)) = Name_Op_Eq + and then Etype (First_Formal (Node (Prim))) = + Etype (Next_Formal (First_Formal (Node (Prim)))) + and then + Base_Type (Etype (Node (Prim))) = Standard_Boolean; + + Next_Elmt (Prim); + end loop; + + pragma Assert (Present (Prim)); + Op_Name := Node (Prim); + end if; + + Build_Equality_Call (Op_Name); + + -- Ada 2005 (AI-216): Program_Error is raised when evaluating the + -- predefined equality operator for a type which has a subcomponent + -- of an Unchecked_Union type whose nominal subtype is unconstrained. + + elsif Has_Unconstrained_UU_Component (Typl) then + Insert_Action (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction)); + + -- Prevent Gigi from generating incorrect code by rewriting the + -- equality as a standard False. (is this documented somewhere???) + + Rewrite (N, + New_Occurrence_Of (Standard_False, Loc)); + + elsif Is_Unchecked_Union (Typl) then + + -- If we can infer the discriminants of the operands, we make a + -- call to the TSS equality function. + + if Has_Inferable_Discriminants (Lhs) + and then + Has_Inferable_Discriminants (Rhs) + then + Build_Equality_Call + (TSS (Root_Type (Typl), TSS_Composite_Equality)); + + else + -- Ada 2005 (AI-216): Program_Error is raised when evaluating + -- the predefined equality operator for an Unchecked_Union type + -- if either of the operands lack inferable discriminants. + + Insert_Action (N, + Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction)); + + -- Emit a warning on source equalities only, otherwise the + -- message may appear out of place due to internal use. The + -- warning is unconditional because it is required by the + -- language. + + if Comes_From_Source (N) then + Error_Msg_N + ("Unchecked_Union discriminants cannot be determined??", + N); + Error_Msg_N + ("\Program_Error will be raised for equality operation??", + N); + end if; + + -- Prevent Gigi from generating incorrect code by rewriting + -- the equality as a standard False (documented where???). + + Rewrite (N, + New_Occurrence_Of (Standard_False, Loc)); + end if; + + -- If a type support function is present (for complex cases), use it + + elsif Present (TSS (Root_Type (Typl), TSS_Composite_Equality)) then + Build_Equality_Call + (TSS (Root_Type (Typl), TSS_Composite_Equality)); + + -- When comparing two Bounded_Strings, use the primitive equality of + -- the root Super_String type. + + elsif Is_Bounded_String (Typl) then + Prim := + First_Elmt (Collect_Primitive_Operations (Root_Type (Typl))); + + while Present (Prim) loop + exit when Chars (Node (Prim)) = Name_Op_Eq + and then Etype (First_Formal (Node (Prim))) = + Etype (Next_Formal (First_Formal (Node (Prim)))) + and then Base_Type (Etype (Node (Prim))) = Standard_Boolean; + + Next_Elmt (Prim); + end loop; + + -- A Super_String type should always have a primitive equality + + pragma Assert (Present (Prim)); + Build_Equality_Call (Node (Prim)); + + -- Otherwise expand the component by component equality. Note that + -- we never use block-bit comparisons for records, because of the + -- problems with gaps. The back end will often be able to recombine + -- the separate comparisons that we generate here. + + else + Remove_Side_Effects (Lhs); + Remove_Side_Effects (Rhs); + Rewrite (N, + Expand_Record_Equality (N, Typl, Lhs, Rhs, Bodies)); + + Insert_Actions (N, Bodies, Suppress => All_Checks); + Analyze_And_Resolve (N, Standard_Boolean, Suppress => All_Checks); + end if; + end if; + + -- Test if result is known at compile time + + Rewrite_Comparison (N); + + -- Special optimization of length comparison + + Optimize_Length_Comparison (N); + + -- One more special case: if we have a comparison of X'Result = expr + -- in floating-point, then if not already there, change expr to be + -- f'Machine (expr) to eliminate surprise from extra precision. + + if Is_Floating_Point_Type (Typl) + and then Nkind (Original_Node (Lhs)) = N_Attribute_Reference + and then Attribute_Name (Original_Node (Lhs)) = Name_Result + then + -- Stick in the Typ'Machine call if not already there + + if Nkind (Rhs) /= N_Attribute_Reference + or else Attribute_Name (Rhs) /= Name_Machine + then + Rewrite (Rhs, + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Typl, Loc), + Attribute_Name => Name_Machine, + Expressions => New_List (Relocate_Node (Rhs)))); + Analyze_And_Resolve (Rhs, Typl); + end if; + end if; + end Expand_N_Op_Eq; + + ----------------------- + -- Expand_N_Op_Expon -- + ----------------------- + + procedure Expand_N_Op_Expon (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Ovflo : constant Boolean := Do_Overflow_Check (N); + Typ : constant Entity_Id := Etype (N); + Rtyp : constant Entity_Id := Root_Type (Typ); + + Bastyp : Entity_Id; + + function Wrap_MA (Exp : Node_Id) return Node_Id; + -- Given an expression Exp, if the root type is Float or Long_Float, + -- then wrap the expression in a call of Bastyp'Machine, to stop any + -- extra precision. This is done to ensure that X**A = X**B when A is + -- a static constant and B is a variable with the same value. For any + -- other type, the node Exp is returned unchanged. + + ------------- + -- Wrap_MA -- + ------------- + + function Wrap_MA (Exp : Node_Id) return Node_Id is + Loc : constant Source_Ptr := Sloc (Exp); + + begin + if Rtyp = Standard_Float or else Rtyp = Standard_Long_Float then + return + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Machine, + Prefix => New_Occurrence_Of (Bastyp, Loc), + Expressions => New_List (Relocate_Node (Exp))); + else + return Exp; + end if; + end Wrap_MA; + + -- Local variables + + Base : Node_Id; + Ent : Entity_Id; + Etyp : Entity_Id; + Exp : Node_Id; + Exptyp : Entity_Id; + Expv : Uint; + Rent : RE_Id; + Temp : Node_Id; + Xnode : Node_Id; + + -- Start of processing for Expand_N_Op_Expon + + begin + Binary_Op_Validity_Checks (N); + + -- CodePeer wants to see the unexpanded N_Op_Expon node + + if CodePeer_Mode then + return; + end if; + + -- Relocation of left and right operands must be done after performing + -- the validity checks since the generation of validation checks may + -- remove side effects. + + Base := Relocate_Node (Left_Opnd (N)); + Bastyp := Etype (Base); + Exp := Relocate_Node (Right_Opnd (N)); + Exptyp := Etype (Exp); + + -- If either operand is of a private type, then we have the use of an + -- intrinsic operator, and we get rid of the privateness, by using root + -- types of underlying types for the actual operation. Otherwise the + -- private types will cause trouble if we expand multiplications or + -- shifts etc. We also do this transformation if the result type is + -- different from the base type. + + if Is_Private_Type (Etype (Base)) + or else Is_Private_Type (Typ) + or else Is_Private_Type (Exptyp) + or else Rtyp /= Root_Type (Bastyp) + then + declare + Bt : constant Entity_Id := Root_Type (Underlying_Type (Bastyp)); + Et : constant Entity_Id := Root_Type (Underlying_Type (Exptyp)); + begin + Rewrite (N, + Unchecked_Convert_To (Typ, + Make_Op_Expon (Loc, + Left_Opnd => Unchecked_Convert_To (Bt, Base), + Right_Opnd => Unchecked_Convert_To (Et, Exp)))); + Analyze_And_Resolve (N, Typ); + return; + end; + end if; + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Test for case of known right argument where we can replace the + -- exponentiation by an equivalent expression using multiplication. + + -- Note: use CRT_Safe version of Compile_Time_Known_Value because in + -- configurable run-time mode, we may not have the exponentiation + -- routine available, and we don't want the legality of the program + -- to depend on how clever the compiler is in knowing values. + + if CRT_Safe_Compile_Time_Known_Value (Exp) then + Expv := Expr_Value (Exp); + + -- We only fold small non-negative exponents. You might think we + -- could fold small negative exponents for the real case, but we + -- can't because we are required to raise Constraint_Error for + -- the case of 0.0 ** (negative) even if Machine_Overflows = False. + -- See ACVC test C4A012B, and it is not worth generating the test. + + -- For small negative exponents, we return the reciprocal of + -- the folding of the exponentiation for the opposite (positive) + -- exponent, as required by Ada RM 4.5.6(11/3). + + if abs Expv <= 4 then + + -- X ** 0 = 1 (or 1.0) + + if Expv = 0 then + + -- Call Remove_Side_Effects to ensure that any side effects + -- in the ignored left operand (in particular function calls + -- to user defined functions) are properly executed. + + Remove_Side_Effects (Base); + + if Ekind (Typ) in Integer_Kind then + Xnode := Make_Integer_Literal (Loc, Intval => 1); + else + Xnode := Make_Real_Literal (Loc, Ureal_1); + end if; + + -- X ** 1 = X + + elsif Expv = 1 then + Xnode := Base; + + -- X ** 2 = X * X + + elsif Expv = 2 then + Xnode := + Wrap_MA ( + Make_Op_Multiply (Loc, + Left_Opnd => Duplicate_Subexpr (Base), + Right_Opnd => Duplicate_Subexpr_No_Checks (Base))); + + -- X ** 3 = X * X * X + + elsif Expv = 3 then + Xnode := + Wrap_MA ( + Make_Op_Multiply (Loc, + Left_Opnd => + Make_Op_Multiply (Loc, + Left_Opnd => Duplicate_Subexpr (Base), + Right_Opnd => Duplicate_Subexpr_No_Checks (Base)), + Right_Opnd => Duplicate_Subexpr_No_Checks (Base))); + + -- X ** 4 -> + + -- do + -- En : constant base'type := base * base; + -- in + -- En * En + + elsif Expv = 4 then + Temp := Make_Temporary (Loc, 'E', Base); + + Xnode := + Make_Expression_With_Actions (Loc, + Actions => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Typ, Loc), + Expression => + Wrap_MA ( + Make_Op_Multiply (Loc, + Left_Opnd => + Duplicate_Subexpr (Base), + Right_Opnd => + Duplicate_Subexpr_No_Checks (Base))))), + + Expression => + Wrap_MA ( + Make_Op_Multiply (Loc, + Left_Opnd => New_Occurrence_Of (Temp, Loc), + Right_Opnd => New_Occurrence_Of (Temp, Loc)))); + + -- X ** N = 1.0 / X ** (-N) + -- N in -4 .. -1 + + else + pragma Assert + (Expv = -1 or Expv = -2 or Expv = -3 or Expv = -4); + + Xnode := + Make_Op_Divide (Loc, + Left_Opnd => + Make_Float_Literal (Loc, + Radix => Uint_1, + Significand => Uint_1, + Exponent => Uint_0), + Right_Opnd => + Make_Op_Expon (Loc, + Left_Opnd => Duplicate_Subexpr (Base), + Right_Opnd => + Make_Integer_Literal (Loc, + Intval => -Expv))); + end if; + + Rewrite (N, Xnode); + Analyze_And_Resolve (N, Typ); + return; + end if; + end if; + + -- Deal with optimizing 2 ** expression to shift where possible + + -- Note: we used to check that Exptyp was an unsigned type. But that is + -- an unnecessary check, since if Exp is negative, we have a run-time + -- error that is either caught (so we get the right result) or we have + -- suppressed the check, in which case the code is erroneous anyway. + + if Is_Integer_Type (Rtyp) + + -- The base value must be "safe compile-time known", and exactly 2 + + and then Nkind (Base) = N_Integer_Literal + and then CRT_Safe_Compile_Time_Known_Value (Base) + and then Expr_Value (Base) = Uint_2 + + -- We only handle cases where the right type is a integer + + and then Is_Integer_Type (Root_Type (Exptyp)) + and then Esize (Root_Type (Exptyp)) <= Esize (Standard_Integer) + + -- This transformation is not applicable for a modular type with a + -- nonbinary modulus because we do not handle modular reduction in + -- a correct manner if we attempt this transformation in this case. + + and then not Non_Binary_Modulus (Typ) + then + -- Handle the cases where our parent is a division or multiplication + -- specially. In these cases we can convert to using a shift at the + -- parent level if we are not doing overflow checking, since it is + -- too tricky to combine the overflow check at the parent level. + + if not Ovflo + and then Nkind_In (Parent (N), N_Op_Divide, N_Op_Multiply) + then + declare + P : constant Node_Id := Parent (N); + L : constant Node_Id := Left_Opnd (P); + R : constant Node_Id := Right_Opnd (P); + + begin + if (Nkind (P) = N_Op_Multiply + and then + ((Is_Integer_Type (Etype (L)) and then R = N) + or else + (Is_Integer_Type (Etype (R)) and then L = N)) + and then not Do_Overflow_Check (P)) + + or else + (Nkind (P) = N_Op_Divide + and then Is_Integer_Type (Etype (L)) + and then Is_Unsigned_Type (Etype (L)) + and then R = N + and then not Do_Overflow_Check (P)) + then + Set_Is_Power_Of_2_For_Shift (N); + return; + end if; + end; + + -- Here we just have 2 ** N on its own, so we can convert this to a + -- shift node. We are prepared to deal with overflow here, and we + -- also have to handle proper modular reduction for binary modular. + + else + declare + OK : Boolean; + Lo : Uint; + Hi : Uint; + + MaxS : Uint; + -- Maximum shift count with no overflow + + TestS : Boolean; + -- Set True if we must test the shift count + + Test_Gt : Node_Id; + -- Node for test against TestS + + begin + -- Compute maximum shift based on the underlying size. For a + -- modular type this is one less than the size. + + if Is_Modular_Integer_Type (Typ) then + + -- For modular integer types, this is the size of the value + -- being shifted minus one. Any larger values will cause + -- modular reduction to a result of zero. Note that we do + -- want the RM_Size here (e.g. mod 2 ** 7, we want a result + -- of 6, since 2**7 should be reduced to zero). + + MaxS := RM_Size (Rtyp) - 1; + + -- For signed integer types, we use the size of the value + -- being shifted minus 2. Larger values cause overflow. + + else + MaxS := Esize (Rtyp) - 2; + end if; + + -- Determine range to see if it can be larger than MaxS + + Determine_Range + (Right_Opnd (N), OK, Lo, Hi, Assume_Valid => True); + TestS := (not OK) or else Hi > MaxS; + + -- Signed integer case + + if Is_Signed_Integer_Type (Typ) then + + -- Generate overflow check if overflow is active. Note that + -- we can simply ignore the possibility of overflow if the + -- flag is not set (means that overflow cannot happen or + -- that overflow checks are suppressed). + + if Ovflo and TestS then + Insert_Action (N, + Make_Raise_Constraint_Error (Loc, + Condition => + Make_Op_Gt (Loc, + Left_Opnd => Duplicate_Subexpr (Right_Opnd (N)), + Right_Opnd => Make_Integer_Literal (Loc, MaxS)), + Reason => CE_Overflow_Check_Failed)); + end if; + + -- Now rewrite node as Shift_Left (1, right-operand) + + Rewrite (N, + Make_Op_Shift_Left (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Uint_1), + Right_Opnd => Right_Opnd (N))); + + -- Modular integer case + + else pragma Assert (Is_Modular_Integer_Type (Typ)); + + -- If shift count can be greater than MaxS, we need to wrap + -- the shift in a test that will reduce the result value to + -- zero if this shift count is exceeded. + + if TestS then + + -- Note: build node for the comparison first, before we + -- reuse the Right_Opnd, so that we have proper parents + -- in place for the Duplicate_Subexpr call. + + Test_Gt := + Make_Op_Gt (Loc, + Left_Opnd => Duplicate_Subexpr (Right_Opnd (N)), + Right_Opnd => Make_Integer_Literal (Loc, MaxS)); + + Rewrite (N, + Make_If_Expression (Loc, + Expressions => New_List ( + Test_Gt, + Make_Integer_Literal (Loc, Uint_0), + Make_Op_Shift_Left (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Uint_1), + Right_Opnd => Right_Opnd (N))))); + + -- If we know shift count cannot be greater than MaxS, then + -- it is safe to just rewrite as a shift with no test. + + else + Rewrite (N, + Make_Op_Shift_Left (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Uint_1), + Right_Opnd => Right_Opnd (N))); + end if; + end if; + + Analyze_And_Resolve (N, Typ); + return; + end; + end if; + end if; + + -- Fall through if exponentiation must be done using a runtime routine + + -- First deal with modular case + + if Is_Modular_Integer_Type (Rtyp) then + + -- Nonbinary modular case, we call the special exponentiation + -- routine for the nonbinary case, converting the argument to + -- Long_Long_Integer and passing the modulus value. Then the + -- result is converted back to the base type. + + if Non_Binary_Modulus (Rtyp) then + Rewrite (N, + Convert_To (Typ, + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Exp_Modular), Loc), + Parameter_Associations => New_List ( + Convert_To (RTE (RE_Unsigned), Base), + Make_Integer_Literal (Loc, Modulus (Rtyp)), + Exp)))); + + -- Binary modular case, in this case, we call one of two routines, + -- either the unsigned integer case, or the unsigned long long + -- integer case, with a final "and" operation to do the required mod. + + else + if UI_To_Int (Esize (Rtyp)) <= Standard_Integer_Size then + Ent := RTE (RE_Exp_Unsigned); + else + Ent := RTE (RE_Exp_Long_Long_Unsigned); + end if; + + Rewrite (N, + Convert_To (Typ, + Make_Op_And (Loc, + Left_Opnd => + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Ent, Loc), + Parameter_Associations => New_List ( + Convert_To (Etype (First_Formal (Ent)), Base), + Exp)), + Right_Opnd => + Make_Integer_Literal (Loc, Modulus (Rtyp) - 1)))); + + end if; + + -- Common exit point for modular type case + + Analyze_And_Resolve (N, Typ); + return; + + -- Signed integer cases, done using either Integer or Long_Long_Integer. + -- It is not worth having routines for Short_[Short_]Integer, since for + -- most machines it would not help, and it would generate more code that + -- might need certification when a certified run time is required. + + -- In the integer cases, we have two routines, one for when overflow + -- checks are required, and one when they are not required, since there + -- is a real gain in omitting checks on many machines. + + elsif Rtyp = Base_Type (Standard_Long_Long_Integer) + or else (Rtyp = Base_Type (Standard_Long_Integer) + and then + Esize (Standard_Long_Integer) > Esize (Standard_Integer)) + or else Rtyp = Universal_Integer + then + Etyp := Standard_Long_Long_Integer; + + if Ovflo then + Rent := RE_Exp_Long_Long_Integer; + else + Rent := RE_Exn_Long_Long_Integer; + end if; + + elsif Is_Signed_Integer_Type (Rtyp) then + Etyp := Standard_Integer; + + if Ovflo then + Rent := RE_Exp_Integer; + else + Rent := RE_Exn_Integer; + end if; + + -- Floating-point cases. We do not need separate routines for the + -- overflow case here, since in the case of floating-point, we generate + -- infinities anyway as a rule (either that or we automatically trap + -- overflow), and if there is an infinity generated and a range check + -- is required, the check will fail anyway. + + -- Historical note: we used to convert everything to Long_Long_Float + -- and call a single common routine, but this had the undesirable effect + -- of giving different results for small static exponent values and the + -- same dynamic values. + + else + pragma Assert (Is_Floating_Point_Type (Rtyp)); + + if Rtyp = Standard_Float then + Etyp := Standard_Float; + Rent := RE_Exn_Float; + + elsif Rtyp = Standard_Long_Float then + Etyp := Standard_Long_Float; + Rent := RE_Exn_Long_Float; + + else + Etyp := Standard_Long_Long_Float; + Rent := RE_Exn_Long_Long_Float; + end if; + end if; + + -- Common processing for integer cases and floating-point cases. + -- If we are in the right type, we can call runtime routine directly + + if Typ = Etyp + and then Rtyp /= Universal_Integer + and then Rtyp /= Universal_Real + then + Rewrite (N, + Wrap_MA ( + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (Rent), Loc), + Parameter_Associations => New_List (Base, Exp)))); + + -- Otherwise we have to introduce conversions (conversions are also + -- required in the universal cases, since the runtime routine is + -- typed using one of the standard types). + + else + Rewrite (N, + Convert_To (Typ, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (Rent), Loc), + Parameter_Associations => New_List ( + Convert_To (Etyp, Base), + Exp)))); + end if; + + Analyze_And_Resolve (N, Typ); + return; + + exception + when RE_Not_Available => + return; + end Expand_N_Op_Expon; + + -------------------- + -- Expand_N_Op_Ge -- + -------------------- + + procedure Expand_N_Op_Ge (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + Op1 : constant Node_Id := Left_Opnd (N); + Op2 : constant Node_Id := Right_Opnd (N); + Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); + + begin + Binary_Op_Validity_Checks (N); + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that + -- means we no longer have a comparison operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Ge then + return; + end if; + + -- Array type case + + if Is_Array_Type (Typ1) then + Expand_Array_Comparison (N); + return; + end if; + + -- Deal with boolean operands + + if Is_Boolean_Type (Typ1) then + Adjust_Condition (Op1); + Adjust_Condition (Op2); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + end if; + + Rewrite_Comparison (N); + + Optimize_Length_Comparison (N); + end Expand_N_Op_Ge; + + -------------------- + -- Expand_N_Op_Gt -- + -------------------- + + procedure Expand_N_Op_Gt (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + Op1 : constant Node_Id := Left_Opnd (N); + Op2 : constant Node_Id := Right_Opnd (N); + Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); + + begin + Binary_Op_Validity_Checks (N); + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that + -- means we no longer have a comparison operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Gt then + return; + end if; + + -- Deal with array type operands + + if Is_Array_Type (Typ1) then + Expand_Array_Comparison (N); + return; + end if; + + -- Deal with boolean type operands + + if Is_Boolean_Type (Typ1) then + Adjust_Condition (Op1); + Adjust_Condition (Op2); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + end if; + + Rewrite_Comparison (N); + + Optimize_Length_Comparison (N); + end Expand_N_Op_Gt; + + -------------------- + -- Expand_N_Op_Le -- + -------------------- + + procedure Expand_N_Op_Le (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + Op1 : constant Node_Id := Left_Opnd (N); + Op2 : constant Node_Id := Right_Opnd (N); + Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); + + begin + Binary_Op_Validity_Checks (N); + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that + -- means we no longer have a comparison operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Le then + return; + end if; + + -- Deal with array type operands + + if Is_Array_Type (Typ1) then + Expand_Array_Comparison (N); + return; + end if; + + -- Deal with Boolean type operands + + if Is_Boolean_Type (Typ1) then + Adjust_Condition (Op1); + Adjust_Condition (Op2); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + end if; + + Rewrite_Comparison (N); + + Optimize_Length_Comparison (N); + end Expand_N_Op_Le; + + -------------------- + -- Expand_N_Op_Lt -- + -------------------- + + procedure Expand_N_Op_Lt (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + Op1 : constant Node_Id := Left_Opnd (N); + Op2 : constant Node_Id := Right_Opnd (N); + Typ1 : constant Entity_Id := Base_Type (Etype (Op1)); + + begin + Binary_Op_Validity_Checks (N); + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if that + -- means we no longer have a comparison operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Lt then + return; + end if; + + -- Deal with array type operands + + if Is_Array_Type (Typ1) then + Expand_Array_Comparison (N); + return; + end if; + + -- Deal with Boolean type operands + + if Is_Boolean_Type (Typ1) then + Adjust_Condition (Op1); + Adjust_Condition (Op2); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + end if; + + Rewrite_Comparison (N); + + Optimize_Length_Comparison (N); + end Expand_N_Op_Lt; + + ----------------------- + -- Expand_N_Op_Minus -- + ----------------------- + + procedure Expand_N_Op_Minus (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + + begin + Unary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + if not Backend_Overflow_Checks_On_Target + and then Is_Signed_Integer_Type (Etype (N)) + and then Do_Overflow_Check (N) + then + -- Software overflow checking expands -expr into (0 - expr) + + Rewrite (N, + Make_Op_Subtract (Loc, + Left_Opnd => Make_Integer_Literal (Loc, 0), + Right_Opnd => Right_Opnd (N))); + + Analyze_And_Resolve (N, Typ); + end if; + + -- When generating C code, convert nonbinary modular minus into code + -- that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Minus; + + --------------------- + -- Expand_N_Op_Mod -- + --------------------- + + procedure Expand_N_Op_Mod (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + DDC : constant Boolean := Do_Division_Check (N); + + Left : Node_Id; + Right : Node_Id; + + LLB : Uint; + Llo : Uint; + Lhi : Uint; + LOK : Boolean; + Rlo : Uint; + Rhi : Uint; + ROK : Boolean; + + pragma Warnings (Off, Lhi); + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + if Is_Integer_Type (Etype (N)) then + Apply_Divide_Checks (N); + + -- All done if we don't have a MOD any more, which can happen as a + -- result of overflow expansion in MINIMIZED or ELIMINATED modes. + + if Nkind (N) /= N_Op_Mod then + return; + end if; + end if; + + -- Proceed with expansion of mod operator + + Left := Left_Opnd (N); + Right := Right_Opnd (N); + + Determine_Range (Right, ROK, Rlo, Rhi, Assume_Valid => True); + Determine_Range (Left, LOK, Llo, Lhi, Assume_Valid => True); + + -- Convert mod to rem if operands are both known to be non-negative, or + -- both known to be non-positive (these are the cases in which rem and + -- mod are the same, see (RM 4.5.5(28-30)). We do this since it is quite + -- likely that this will improve the quality of code, (the operation now + -- corresponds to the hardware remainder), and it does not seem likely + -- that it could be harmful. It also avoids some cases of the elaborate + -- expansion in Modify_Tree_For_C mode below (since Ada rem = C %). + + if (LOK and ROK) + and then ((Llo >= 0 and then Rlo >= 0) + or else + (Lhi <= 0 and then Rhi <= 0)) + then + Rewrite (N, + Make_Op_Rem (Sloc (N), + Left_Opnd => Left_Opnd (N), + Right_Opnd => Right_Opnd (N))); + + -- Instead of reanalyzing the node we do the analysis manually. This + -- avoids anomalies when the replacement is done in an instance and + -- is epsilon more efficient. + + Set_Entity (N, Standard_Entity (S_Op_Rem)); + Set_Etype (N, Typ); + Set_Do_Division_Check (N, DDC); + Expand_N_Op_Rem (N); + Set_Analyzed (N); + return; + + -- Otherwise, normal mod processing + + else + -- Apply optimization x mod 1 = 0. We don't really need that with + -- gcc, but it is useful with other back ends and is certainly + -- harmless. + + if Is_Integer_Type (Etype (N)) + and then Compile_Time_Known_Value (Right) + and then Expr_Value (Right) = Uint_1 + then + -- Call Remove_Side_Effects to ensure that any side effects in + -- the ignored left operand (in particular function calls to + -- user defined functions) are properly executed. + + Remove_Side_Effects (Left); + + Rewrite (N, Make_Integer_Literal (Loc, 0)); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- If we still have a mod operator and we are in Modify_Tree_For_C + -- mode, and we have a signed integer type, then here is where we do + -- the rewrite in terms of Rem. Note this rewrite bypasses the need + -- for the special handling of the annoying case of largest negative + -- number mod minus one. + + if Nkind (N) = N_Op_Mod + and then Is_Signed_Integer_Type (Typ) + and then Modify_Tree_For_C + then + -- In the general case, we expand A mod B as + + -- Tnn : constant typ := A rem B; + -- .. + -- (if (A >= 0) = (B >= 0) then Tnn + -- elsif Tnn = 0 then 0 + -- else Tnn + B) + + -- The comparison can be written simply as A >= 0 if we know that + -- B >= 0 which is a very common case. + + -- An important optimization is when B is known at compile time + -- to be 2**K for some constant. In this case we can simply AND + -- the left operand with the bit string 2**K-1 (i.e. K 1-bits) + -- and that works for both the positive and negative cases. + + declare + P2 : constant Nat := Power_Of_Two (Right); + + begin + if P2 /= 0 then + Rewrite (N, + Unchecked_Convert_To (Typ, + Make_Op_And (Loc, + Left_Opnd => + Unchecked_Convert_To + (Corresponding_Unsigned_Type (Typ), Left), + Right_Opnd => + Make_Integer_Literal (Loc, 2 ** P2 - 1)))); + Analyze_And_Resolve (N, Typ); + return; + end if; + end; + + -- Here for the full rewrite + + declare + Tnn : constant Entity_Id := Make_Temporary (Sloc (N), 'T', N); + Cmp : Node_Id; + + begin + Cmp := + Make_Op_Ge (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Left), + Right_Opnd => Make_Integer_Literal (Loc, 0)); + + if not LOK or else Rlo < 0 then + Cmp := + Make_Op_Eq (Loc, + Left_Opnd => Cmp, + Right_Opnd => + Make_Op_Ge (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Right), + Right_Opnd => Make_Integer_Literal (Loc, 0))); + end if; + + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Tnn, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Typ, Loc), + Expression => + Make_Op_Rem (Loc, + Left_Opnd => Left, + Right_Opnd => Right))); + + Rewrite (N, + Make_If_Expression (Loc, + Expressions => New_List ( + Cmp, + New_Occurrence_Of (Tnn, Loc), + Make_If_Expression (Loc, + Is_Elsif => True, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (Tnn, Loc), + Right_Opnd => Make_Integer_Literal (Loc, 0)), + Make_Integer_Literal (Loc, 0), + Make_Op_Add (Loc, + Left_Opnd => New_Occurrence_Of (Tnn, Loc), + Right_Opnd => + Duplicate_Subexpr_No_Checks (Right))))))); + + Analyze_And_Resolve (N, Typ); + return; + end; + end if; + + -- Deal with annoying case of largest negative number mod minus one. + -- Gigi may not handle this case correctly, because on some targets, + -- the mod value is computed using a divide instruction which gives + -- an overflow trap for this case. + + -- It would be a bit more efficient to figure out which targets + -- this is really needed for, but in practice it is reasonable + -- to do the following special check in all cases, since it means + -- we get a clearer message, and also the overhead is minimal given + -- that division is expensive in any case. + + -- In fact the check is quite easy, if the right operand is -1, then + -- the mod value is always 0, and we can just ignore the left operand + -- completely in this case. + + -- This only applies if we still have a mod operator. Skip if we + -- have already rewritten this (e.g. in the case of eliminated + -- overflow checks which have driven us into bignum mode). + + if Nkind (N) = N_Op_Mod then + + -- The operand type may be private (e.g. in the expansion of an + -- intrinsic operation) so we must use the underlying type to get + -- the bounds, and convert the literals explicitly. + + LLB := + Expr_Value + (Type_Low_Bound (Base_Type (Underlying_Type (Etype (Left))))); + + if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) + and then ((not LOK) or else (Llo = LLB)) + then + Rewrite (N, + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => Duplicate_Subexpr (Right), + Right_Opnd => + Unchecked_Convert_To (Typ, + Make_Integer_Literal (Loc, -1))), + Unchecked_Convert_To (Typ, + Make_Integer_Literal (Loc, Uint_0)), + Relocate_Node (N)))); + + Set_Analyzed (Next (Next (First (Expressions (N))))); + Analyze_And_Resolve (N, Typ); + end if; + end if; + end if; + end Expand_N_Op_Mod; + + -------------------------- + -- Expand_N_Op_Multiply -- + -------------------------- + + procedure Expand_N_Op_Multiply (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Lop : constant Node_Id := Left_Opnd (N); + Rop : constant Node_Id := Right_Opnd (N); + + Lp2 : constant Boolean := + Nkind (Lop) = N_Op_Expon and then Is_Power_Of_2_For_Shift (Lop); + Rp2 : constant Boolean := + Nkind (Rop) = N_Op_Expon and then Is_Power_Of_2_For_Shift (Rop); + + Ltyp : constant Entity_Id := Etype (Lop); + Rtyp : constant Entity_Id := Etype (Rop); + Typ : Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- Special optimizations for integer types + + if Is_Integer_Type (Typ) then + + -- N * 0 = 0 for integer types + + if Compile_Time_Known_Value (Rop) + and then Expr_Value (Rop) = Uint_0 + then + -- Call Remove_Side_Effects to ensure that any side effects in + -- the ignored left operand (in particular function calls to + -- user defined functions) are properly executed. + + Remove_Side_Effects (Lop); + + Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Similar handling for 0 * N = 0 + + if Compile_Time_Known_Value (Lop) + and then Expr_Value (Lop) = Uint_0 + then + Remove_Side_Effects (Rop); + Rewrite (N, Make_Integer_Literal (Loc, Uint_0)); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- N * 1 = 1 * N = N for integer types + + -- This optimisation is not done if we are going to + -- rewrite the product 1 * 2 ** N to a shift. + + if Compile_Time_Known_Value (Rop) + and then Expr_Value (Rop) = Uint_1 + and then not Lp2 + then + Rewrite (N, Lop); + return; + + elsif Compile_Time_Known_Value (Lop) + and then Expr_Value (Lop) = Uint_1 + and then not Rp2 + then + Rewrite (N, Rop); + return; + end if; + end if; + + -- Convert x * 2 ** y to Shift_Left (x, y). Note that the fact that + -- Is_Power_Of_2_For_Shift is set means that we know that our left + -- operand is an integer, as required for this to work. + + if Rp2 then + if Lp2 then + + -- Convert 2 ** A * 2 ** B into 2 ** (A + B) + + Rewrite (N, + Make_Op_Expon (Loc, + Left_Opnd => Make_Integer_Literal (Loc, 2), + Right_Opnd => + Make_Op_Add (Loc, + Left_Opnd => Right_Opnd (Lop), + Right_Opnd => Right_Opnd (Rop)))); + Analyze_And_Resolve (N, Typ); + return; + + else + -- If the result is modular, perform the reduction of the result + -- appropriately. + + if Is_Modular_Integer_Type (Typ) + and then not Non_Binary_Modulus (Typ) + then + Rewrite (N, + Make_Op_And (Loc, + Left_Opnd => + Make_Op_Shift_Left (Loc, + Left_Opnd => Lop, + Right_Opnd => + Convert_To (Standard_Natural, Right_Opnd (Rop))), + Right_Opnd => + Make_Integer_Literal (Loc, Modulus (Typ) - 1))); + + else + Rewrite (N, + Make_Op_Shift_Left (Loc, + Left_Opnd => Lop, + Right_Opnd => + Convert_To (Standard_Natural, Right_Opnd (Rop)))); + end if; + + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Same processing for the operands the other way round + + elsif Lp2 then + if Is_Modular_Integer_Type (Typ) + and then not Non_Binary_Modulus (Typ) + then + Rewrite (N, + Make_Op_And (Loc, + Left_Opnd => + Make_Op_Shift_Left (Loc, + Left_Opnd => Rop, + Right_Opnd => + Convert_To (Standard_Natural, Right_Opnd (Lop))), + Right_Opnd => + Make_Integer_Literal (Loc, Modulus (Typ) - 1))); + + else + Rewrite (N, + Make_Op_Shift_Left (Loc, + Left_Opnd => Rop, + Right_Opnd => + Convert_To (Standard_Natural, Right_Opnd (Lop)))); + end if; + + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Do required fixup of universal fixed operation + + if Typ = Universal_Fixed then + Fixup_Universal_Fixed_Operation (N); + Typ := Etype (N); + end if; + + -- Multiplications with fixed-point results + + if Is_Fixed_Point_Type (Typ) then + + -- No special processing if Treat_Fixed_As_Integer is set, since from + -- a semantic point of view such operations are simply integer + -- operations and will be treated that way. + + if not Treat_Fixed_As_Integer (N) then + + -- Case of fixed * integer => fixed + + if Is_Integer_Type (Rtyp) then + Expand_Multiply_Fixed_By_Integer_Giving_Fixed (N); + + -- Case of integer * fixed => fixed + + elsif Is_Integer_Type (Ltyp) then + Expand_Multiply_Integer_By_Fixed_Giving_Fixed (N); + + -- Case of fixed * fixed => fixed + + else + Expand_Multiply_Fixed_By_Fixed_Giving_Fixed (N); + end if; + end if; + + -- Other cases of multiplication of fixed-point operands. Again we + -- exclude the cases where Treat_Fixed_As_Integer flag is set. + + elsif (Is_Fixed_Point_Type (Ltyp) or else Is_Fixed_Point_Type (Rtyp)) + and then not Treat_Fixed_As_Integer (N) + then + if Is_Integer_Type (Typ) then + Expand_Multiply_Fixed_By_Fixed_Giving_Integer (N); + else + pragma Assert (Is_Floating_Point_Type (Typ)); + Expand_Multiply_Fixed_By_Fixed_Giving_Float (N); + end if; + + -- Mixed-mode operations can appear in a non-static universal context, + -- in which case the integer argument must be converted explicitly. + + elsif Typ = Universal_Real and then Is_Integer_Type (Rtyp) then + Rewrite (Rop, Convert_To (Universal_Real, Relocate_Node (Rop))); + Analyze_And_Resolve (Rop, Universal_Real); + + elsif Typ = Universal_Real and then Is_Integer_Type (Ltyp) then + Rewrite (Lop, Convert_To (Universal_Real, Relocate_Node (Lop))); + Analyze_And_Resolve (Lop, Universal_Real); + + -- Non-fixed point cases, check software overflow checking required + + elsif Is_Signed_Integer_Type (Etype (N)) then + Apply_Arithmetic_Overflow_Check (N); + end if; + + -- Overflow checks for floating-point if -gnateF mode active + + Check_Float_Op_Overflow (N); + + -- When generating C code, convert nonbinary modular multiplications + -- into code that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Multiply; + + -------------------- + -- Expand_N_Op_Ne -- + -------------------- + + procedure Expand_N_Op_Ne (N : Node_Id) is + Typ : constant Entity_Id := Etype (Left_Opnd (N)); + + begin + -- Case of elementary type with standard operator + + if Is_Elementary_Type (Typ) + and then Sloc (Entity (N)) = Standard_Location + then + Binary_Op_Validity_Checks (N); + + -- Deal with overflow checks in MINIMIZED/ELIMINATED mode and if + -- means we no longer have a /= operation, we are all done. + + Expand_Compare_Minimize_Eliminate_Overflow (N); + + if Nkind (N) /= N_Op_Ne then + return; + end if; + + -- Boolean types (requiring handling of non-standard case) + + if Is_Boolean_Type (Typ) then + Adjust_Condition (Left_Opnd (N)); + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + end if; + + Rewrite_Comparison (N); + + -- For all cases other than elementary types, we rewrite node as the + -- negation of an equality operation, and reanalyze. The equality to be + -- used is defined in the same scope and has the same signature. This + -- signature must be set explicitly since in an instance it may not have + -- the same visibility as in the generic unit. This avoids duplicating + -- or factoring the complex code for record/array equality tests etc. + + -- This case is also used for the minimal expansion performed in + -- GNATprove mode. + + else + declare + Loc : constant Source_Ptr := Sloc (N); + Neg : Node_Id; + Ne : constant Entity_Id := Entity (N); + + begin + Binary_Op_Validity_Checks (N); + + Neg := + Make_Op_Not (Loc, + Right_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => Left_Opnd (N), + Right_Opnd => Right_Opnd (N))); + + -- The level of parentheses is useless in GNATprove mode, and + -- bumping its level here leads to wrong columns being used in + -- check messages, hence skip it in this mode. + + if not GNATprove_Mode then + Set_Paren_Count (Right_Opnd (Neg), 1); + end if; + + if Scope (Ne) /= Standard_Standard then + Set_Entity (Right_Opnd (Neg), Corresponding_Equality (Ne)); + end if; + + -- For navigation purposes, we want to treat the inequality as an + -- implicit reference to the corresponding equality. Preserve the + -- Comes_From_ source flag to generate proper Xref entries. + + Preserve_Comes_From_Source (Neg, N); + Preserve_Comes_From_Source (Right_Opnd (Neg), N); + Rewrite (N, Neg); + Analyze_And_Resolve (N, Standard_Boolean); + end; + end if; + + -- No need for optimization in GNATprove mode, where we would rather see + -- the original source expression. + + if not GNATprove_Mode then + Optimize_Length_Comparison (N); + end if; + end Expand_N_Op_Ne; + + --------------------- + -- Expand_N_Op_Not -- + --------------------- + + -- If the argument is other than a Boolean array type, there is no special + -- expansion required, except for dealing with validity checks, and non- + -- standard boolean representations. + + -- For the packed array case, we call the special routine in Exp_Pakd, + -- except that if the component size is greater than one, we use the + -- standard routine generating a gruesome loop (it is so peculiar to have + -- packed arrays with non-standard Boolean representations anyway, so it + -- does not matter that we do not handle this case efficiently). + + -- For the unpacked array case (and for the special packed case where we + -- have non standard Booleans, as discussed above), we generate and insert + -- into the tree the following function definition: + + -- function Nnnn (A : arr) is + -- B : arr; + -- begin + -- for J in a'range loop + -- B (J) := not A (J); + -- end loop; + -- return B; + -- end Nnnn; + + -- Here arr is the actual subtype of the parameter (and hence always + -- constrained). Then we replace the not with a call to this function. + + procedure Expand_N_Op_Not (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Opnd : Node_Id; + Arr : Entity_Id; + A : Entity_Id; + B : Entity_Id; + J : Entity_Id; + A_J : Node_Id; + B_J : Node_Id; + + Func_Name : Entity_Id; + Loop_Statement : Node_Id; + + begin + Unary_Op_Validity_Checks (N); + + -- For boolean operand, deal with non-standard booleans + + if Is_Boolean_Type (Typ) then + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + return; + end if; + + -- Only array types need any other processing + + if not Is_Array_Type (Typ) then + return; + end if; + + -- Case of array operand. If bit packed with a component size of 1, + -- handle it in Exp_Pakd if the operand is known to be aligned. + + if Is_Bit_Packed_Array (Typ) + and then Component_Size (Typ) = 1 + and then not Is_Possibly_Unaligned_Object (Right_Opnd (N)) + then + Expand_Packed_Not (N); + return; + end if; + + -- Case of array operand which is not bit-packed. If the context is + -- a safe assignment, call in-place operation, If context is a larger + -- boolean expression in the context of a safe assignment, expansion is + -- done by enclosing operation. + + Opnd := Relocate_Node (Right_Opnd (N)); + Convert_To_Actual_Subtype (Opnd); + Arr := Etype (Opnd); + Ensure_Defined (Arr, N); + Silly_Boolean_Array_Not_Test (N, Arr); + + if Nkind (Parent (N)) = N_Assignment_Statement then + if Safe_In_Place_Array_Op (Name (Parent (N)), N, Empty) then + Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); + return; + + -- Special case the negation of a binary operation + + elsif Nkind_In (Opnd, N_Op_And, N_Op_Or, N_Op_Xor) + and then Safe_In_Place_Array_Op + (Name (Parent (N)), Left_Opnd (Opnd), Right_Opnd (Opnd)) + then + Build_Boolean_Array_Proc_Call (Parent (N), Opnd, Empty); + return; + end if; + + elsif Nkind (Parent (N)) in N_Binary_Op + and then Nkind (Parent (Parent (N))) = N_Assignment_Statement + then + declare + Op1 : constant Node_Id := Left_Opnd (Parent (N)); + Op2 : constant Node_Id := Right_Opnd (Parent (N)); + Lhs : constant Node_Id := Name (Parent (Parent (N))); + + begin + if Safe_In_Place_Array_Op (Lhs, Op1, Op2) then + + -- (not A) op (not B) can be reduced to a single call + + if N = Op1 and then Nkind (Op2) = N_Op_Not then + return; + + elsif N = Op2 and then Nkind (Op1) = N_Op_Not then + return; + + -- A xor (not B) can also be special-cased + + elsif N = Op2 and then Nkind (Parent (N)) = N_Op_Xor then + return; + end if; + end if; + end; + end if; + + A := Make_Defining_Identifier (Loc, Name_uA); + B := Make_Defining_Identifier (Loc, Name_uB); + J := Make_Defining_Identifier (Loc, Name_uJ); + + A_J := + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (A, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc))); + + B_J := + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (B, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc))); + + Loop_Statement := + Make_Implicit_Loop_Statement (N, + Identifier => Empty, + + Iteration_Scheme => + Make_Iteration_Scheme (Loc, + Loop_Parameter_Specification => + Make_Loop_Parameter_Specification (Loc, + Defining_Identifier => J, + Discrete_Subtype_Definition => + Make_Attribute_Reference (Loc, + Prefix => Make_Identifier (Loc, Chars (A)), + Attribute_Name => Name_Range))), + + Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => B_J, + Expression => Make_Op_Not (Loc, A_J)))); + + Func_Name := Make_Temporary (Loc, 'N'); + Set_Is_Inlined (Func_Name); + + Insert_Action (N, + Make_Subprogram_Body (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Func_Name, + Parameter_Specifications => New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => A, + Parameter_Type => New_Occurrence_Of (Typ, Loc))), + Result_Definition => New_Occurrence_Of (Typ, Loc)), + + Declarations => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => B, + Object_Definition => New_Occurrence_Of (Arr, Loc))), + + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Loop_Statement, + Make_Simple_Return_Statement (Loc, + Expression => Make_Identifier (Loc, Chars (B))))))); + + Rewrite (N, + Make_Function_Call (Loc, + Name => New_Occurrence_Of (Func_Name, Loc), + Parameter_Associations => New_List (Opnd))); + + Analyze_And_Resolve (N, Typ); + end Expand_N_Op_Not; + + -------------------- + -- Expand_N_Op_Or -- + -------------------- + + procedure Expand_N_Op_Or (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + if Is_Array_Type (Etype (N)) then + Expand_Boolean_Operator (N); + + elsif Is_Boolean_Type (Etype (N)) then + Adjust_Condition (Left_Opnd (N)); + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + + elsif Is_Intrinsic_Subprogram (Entity (N)) then + Expand_Intrinsic_Call (N, Entity (N)); + end if; + + -- When generating C code, convert nonbinary modular operators into code + -- that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Or; + + ---------------------- + -- Expand_N_Op_Plus -- + ---------------------- + + procedure Expand_N_Op_Plus (N : Node_Id) is + begin + Unary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + end Expand_N_Op_Plus; + + --------------------- + -- Expand_N_Op_Rem -- + --------------------- + + procedure Expand_N_Op_Rem (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + + Left : Node_Id; + Right : Node_Id; + + Lo : Uint; + Hi : Uint; + OK : Boolean; + + Lneg : Boolean; + Rneg : Boolean; + -- Set if corresponding operand can be negative + + pragma Unreferenced (Hi); + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + if Is_Integer_Type (Etype (N)) then + Apply_Divide_Checks (N); + + -- All done if we don't have a REM any more, which can happen as a + -- result of overflow expansion in MINIMIZED or ELIMINATED modes. + + if Nkind (N) /= N_Op_Rem then + return; + end if; + end if; + + -- Proceed with expansion of REM + + Left := Left_Opnd (N); + Right := Right_Opnd (N); + + -- Apply optimization x rem 1 = 0. We don't really need that with gcc, + -- but it is useful with other back ends, and is certainly harmless. + + if Is_Integer_Type (Etype (N)) + and then Compile_Time_Known_Value (Right) + and then Expr_Value (Right) = Uint_1 + then + -- Call Remove_Side_Effects to ensure that any side effects in the + -- ignored left operand (in particular function calls to user defined + -- functions) are properly executed. + + Remove_Side_Effects (Left); + + Rewrite (N, Make_Integer_Literal (Loc, 0)); + Analyze_And_Resolve (N, Typ); + return; + end if; + + -- Deal with annoying case of largest negative number remainder minus + -- one. Gigi may not handle this case correctly, because on some + -- targets, the mod value is computed using a divide instruction + -- which gives an overflow trap for this case. + + -- It would be a bit more efficient to figure out which targets this + -- is really needed for, but in practice it is reasonable to do the + -- following special check in all cases, since it means we get a clearer + -- message, and also the overhead is minimal given that division is + -- expensive in any case. + + -- In fact the check is quite easy, if the right operand is -1, then + -- the remainder is always 0, and we can just ignore the left operand + -- completely in this case. + + Determine_Range (Right, OK, Lo, Hi, Assume_Valid => True); + Lneg := (not OK) or else Lo < 0; + + Determine_Range (Left, OK, Lo, Hi, Assume_Valid => True); + Rneg := (not OK) or else Lo < 0; + + -- We won't mess with trying to find out if the left operand can really + -- be the largest negative number (that's a pain in the case of private + -- types and this is really marginal). We will just assume that we need + -- the test if the left operand can be negative at all. + + if Lneg and Rneg then + Rewrite (N, + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Eq (Loc, + Left_Opnd => Duplicate_Subexpr (Right), + Right_Opnd => + Unchecked_Convert_To (Typ, Make_Integer_Literal (Loc, -1))), + + Unchecked_Convert_To (Typ, + Make_Integer_Literal (Loc, Uint_0)), + + Relocate_Node (N)))); + + Set_Analyzed (Next (Next (First (Expressions (N))))); + Analyze_And_Resolve (N, Typ); + end if; + end Expand_N_Op_Rem; + + ----------------------------- + -- Expand_N_Op_Rotate_Left -- + ----------------------------- + + procedure Expand_N_Op_Rotate_Left (N : Node_Id) is + begin + Binary_Op_Validity_Checks (N); + + -- If we are in Modify_Tree_For_C mode, there is no rotate left in C, + -- so we rewrite in terms of logical shifts + + -- Shift_Left (Num, Bits) or Shift_Right (num, Esize - Bits) + + -- where Bits is the shift count mod Esize (the mod operation here + -- deals with ludicrous large shift counts, which are apparently OK). + + -- What about nonbinary modulus ??? + + declare + Loc : constant Source_Ptr := Sloc (N); + Rtp : constant Entity_Id := Etype (Right_Opnd (N)); + Typ : constant Entity_Id := Etype (N); + + begin + if Modify_Tree_For_C then + Rewrite (Right_Opnd (N), + Make_Op_Rem (Loc, + Left_Opnd => Relocate_Node (Right_Opnd (N)), + Right_Opnd => Make_Integer_Literal (Loc, Esize (Typ)))); + + Analyze_And_Resolve (Right_Opnd (N), Rtp); + + Rewrite (N, + Make_Op_Or (Loc, + Left_Opnd => + Make_Op_Shift_Left (Loc, + Left_Opnd => Left_Opnd (N), + Right_Opnd => Right_Opnd (N)), + + Right_Opnd => + Make_Op_Shift_Right (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Left_Opnd (N)), + Right_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Esize (Typ)), + Right_Opnd => + Duplicate_Subexpr_No_Checks (Right_Opnd (N)))))); + + Analyze_And_Resolve (N, Typ); + end if; + end; + end Expand_N_Op_Rotate_Left; + + ------------------------------ + -- Expand_N_Op_Rotate_Right -- + ------------------------------ + + procedure Expand_N_Op_Rotate_Right (N : Node_Id) is + begin + Binary_Op_Validity_Checks (N); + + -- If we are in Modify_Tree_For_C mode, there is no rotate right in C, + -- so we rewrite in terms of logical shifts + + -- Shift_Right (Num, Bits) or Shift_Left (num, Esize - Bits) + + -- where Bits is the shift count mod Esize (the mod operation here + -- deals with ludicrous large shift counts, which are apparently OK). + + -- What about nonbinary modulus ??? + + declare + Loc : constant Source_Ptr := Sloc (N); + Rtp : constant Entity_Id := Etype (Right_Opnd (N)); + Typ : constant Entity_Id := Etype (N); + + begin + Rewrite (Right_Opnd (N), + Make_Op_Rem (Loc, + Left_Opnd => Relocate_Node (Right_Opnd (N)), + Right_Opnd => Make_Integer_Literal (Loc, Esize (Typ)))); + + Analyze_And_Resolve (Right_Opnd (N), Rtp); + + if Modify_Tree_For_C then + Rewrite (N, + Make_Op_Or (Loc, + Left_Opnd => + Make_Op_Shift_Right (Loc, + Left_Opnd => Left_Opnd (N), + Right_Opnd => Right_Opnd (N)), + + Right_Opnd => + Make_Op_Shift_Left (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Left_Opnd (N)), + Right_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Esize (Typ)), + Right_Opnd => + Duplicate_Subexpr_No_Checks (Right_Opnd (N)))))); + + Analyze_And_Resolve (N, Typ); + end if; + end; + end Expand_N_Op_Rotate_Right; + + ---------------------------- + -- Expand_N_Op_Shift_Left -- + ---------------------------- + + -- Note: nothing in this routine depends on left as opposed to right shifts + -- so we share the routine for expanding shift right operations. + + procedure Expand_N_Op_Shift_Left (N : Node_Id) is + begin + Binary_Op_Validity_Checks (N); + + -- If we are in Modify_Tree_For_C mode, then ensure that the right + -- operand is not greater than the word size (since that would not + -- be defined properly by the corresponding C shift operator). + + if Modify_Tree_For_C then + declare + Right : constant Node_Id := Right_Opnd (N); + Loc : constant Source_Ptr := Sloc (Right); + Typ : constant Entity_Id := Etype (N); + Siz : constant Uint := Esize (Typ); + Orig : Node_Id; + OK : Boolean; + Lo : Uint; + Hi : Uint; + + begin + if Compile_Time_Known_Value (Right) then + if Expr_Value (Right) >= Siz then + Rewrite (N, Make_Integer_Literal (Loc, 0)); + Analyze_And_Resolve (N, Typ); + end if; + + -- Not compile time known, find range + + else + Determine_Range (Right, OK, Lo, Hi, Assume_Valid => True); + + -- Nothing to do if known to be OK range, otherwise expand + + if not OK or else Hi >= Siz then + + -- Prevent recursion on copy of shift node + + Orig := Relocate_Node (N); + Set_Analyzed (Orig); + + -- Now do the rewrite + + Rewrite (N, + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Ge (Loc, + Left_Opnd => Duplicate_Subexpr_Move_Checks (Right), + Right_Opnd => Make_Integer_Literal (Loc, Siz)), + Make_Integer_Literal (Loc, 0), + Orig))); + Analyze_And_Resolve (N, Typ); + end if; + end if; + end; + end if; + end Expand_N_Op_Shift_Left; + + ----------------------------- + -- Expand_N_Op_Shift_Right -- + ----------------------------- + + procedure Expand_N_Op_Shift_Right (N : Node_Id) is + begin + -- Share shift left circuit + + Expand_N_Op_Shift_Left (N); + end Expand_N_Op_Shift_Right; + + ---------------------------------------- + -- Expand_N_Op_Shift_Right_Arithmetic -- + ---------------------------------------- + + procedure Expand_N_Op_Shift_Right_Arithmetic (N : Node_Id) is + begin + Binary_Op_Validity_Checks (N); + + -- If we are in Modify_Tree_For_C mode, there is no shift right + -- arithmetic in C, so we rewrite in terms of logical shifts. + + -- Shift_Right (Num, Bits) or + -- (if Num >= Sign + -- then not (Shift_Right (Mask, bits)) + -- else 0) + + -- Here Mask is all 1 bits (2**size - 1), and Sign is 2**(size - 1) + + -- Note: in almost all C compilers it would work to just shift a + -- signed integer right, but it's undefined and we cannot rely on it. + + -- Note: the above works fine for shift counts greater than or equal + -- to the word size, since in this case (not (Shift_Right (Mask, bits))) + -- generates all 1'bits. + + -- What about nonbinary modulus ??? + + declare + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Sign : constant Uint := 2 ** (Esize (Typ) - 1); + Mask : constant Uint := (2 ** Esize (Typ)) - 1; + Left : constant Node_Id := Left_Opnd (N); + Right : constant Node_Id := Right_Opnd (N); + Maskx : Node_Id; + + begin + if Modify_Tree_For_C then + + -- Here if not (Shift_Right (Mask, bits)) can be computed at + -- compile time as a single constant. + + if Compile_Time_Known_Value (Right) then + declare + Val : constant Uint := Expr_Value (Right); + + begin + if Val >= Esize (Typ) then + Maskx := Make_Integer_Literal (Loc, Mask); + + else + Maskx := + Make_Integer_Literal (Loc, + Intval => Mask - (Mask / (2 ** Expr_Value (Right)))); + end if; + end; + + else + Maskx := + Make_Op_Not (Loc, + Right_Opnd => + Make_Op_Shift_Right (Loc, + Left_Opnd => Make_Integer_Literal (Loc, Mask), + Right_Opnd => Duplicate_Subexpr_No_Checks (Right))); + end if; + + -- Now do the rewrite + + Rewrite (N, + Make_Op_Or (Loc, + Left_Opnd => + Make_Op_Shift_Right (Loc, + Left_Opnd => Left, + Right_Opnd => Right), + Right_Opnd => + Make_If_Expression (Loc, + Expressions => New_List ( + Make_Op_Ge (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Left), + Right_Opnd => Make_Integer_Literal (Loc, Sign)), + Maskx, + Make_Integer_Literal (Loc, 0))))); + Analyze_And_Resolve (N, Typ); + end if; + end; + end Expand_N_Op_Shift_Right_Arithmetic; + + -------------------------- + -- Expand_N_Op_Subtract -- + -------------------------- + + procedure Expand_N_Op_Subtract (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + -- Check for MINIMIZED/ELIMINATED overflow mode + + if Minimized_Eliminated_Overflow_Check (N) then + Apply_Arithmetic_Overflow_Check (N); + return; + end if; + + -- N - 0 = N for integer types + + if Is_Integer_Type (Typ) + and then Compile_Time_Known_Value (Right_Opnd (N)) + and then Expr_Value (Right_Opnd (N)) = 0 + then + Rewrite (N, Left_Opnd (N)); + return; + end if; + + -- Arithmetic overflow checks for signed integer/fixed point types + + if Is_Signed_Integer_Type (Typ) or else Is_Fixed_Point_Type (Typ) then + Apply_Arithmetic_Overflow_Check (N); + end if; + + -- Overflow checks for floating-point if -gnateF mode active + + Check_Float_Op_Overflow (N); + + -- When generating C code, convert nonbinary modular subtractions into + -- code that relies on the front-end expansion of operator Mod. + + if Modify_Tree_For_C then + Expand_Nonbinary_Modular_Op (N); + end if; + end Expand_N_Op_Subtract; + + --------------------- + -- Expand_N_Op_Xor -- + --------------------- + + procedure Expand_N_Op_Xor (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + begin + Binary_Op_Validity_Checks (N); + + if Is_Array_Type (Etype (N)) then + Expand_Boolean_Operator (N); + + elsif Is_Boolean_Type (Etype (N)) then + Adjust_Condition (Left_Opnd (N)); + Adjust_Condition (Right_Opnd (N)); + Set_Etype (N, Standard_Boolean); + Adjust_Result_Type (N, Typ); + + elsif Is_Intrinsic_Subprogram (Entity (N)) then + Expand_Intrinsic_Call (N, Entity (N)); + + end if; + end Expand_N_Op_Xor; + + ---------------------- + -- Expand_N_Or_Else -- + ---------------------- + + procedure Expand_N_Or_Else (N : Node_Id) + renames Expand_Short_Circuit_Operator; + + ----------------------------------- + -- Expand_N_Qualified_Expression -- + ----------------------------------- + + procedure Expand_N_Qualified_Expression (N : Node_Id) is + Operand : constant Node_Id := Expression (N); + Target_Type : constant Entity_Id := Entity (Subtype_Mark (N)); + + begin + -- Do validity check if validity checking operands + + if Validity_Checks_On and Validity_Check_Operands then + Ensure_Valid (Operand); + end if; + + -- Apply possible constraint check + + Apply_Constraint_Check (Operand, Target_Type, No_Sliding => True); + + if Do_Range_Check (Operand) then + Set_Do_Range_Check (Operand, False); + Generate_Range_Check (Operand, Target_Type, CE_Range_Check_Failed); + end if; + end Expand_N_Qualified_Expression; + + ------------------------------------ + -- Expand_N_Quantified_Expression -- + ------------------------------------ + + -- We expand: + + -- for all X in range => Cond + + -- into: + + -- T := True; + -- for X in range loop + -- if not Cond then + -- T := False; + -- exit; + -- end if; + -- end loop; + + -- Similarly, an existentially quantified expression: + + -- for some X in range => Cond + + -- becomes: + + -- T := False; + -- for X in range loop + -- if Cond then + -- T := True; + -- exit; + -- end if; + -- end loop; + + -- In both cases, the iteration may be over a container in which case it is + -- given by an iterator specification, not a loop parameter specification. + + procedure Expand_N_Quantified_Expression (N : Node_Id) is + Actions : constant List_Id := New_List; + For_All : constant Boolean := All_Present (N); + Iter_Spec : constant Node_Id := Iterator_Specification (N); + Loc : constant Source_Ptr := Sloc (N); + Loop_Spec : constant Node_Id := Loop_Parameter_Specification (N); + Cond : Node_Id; + Flag : Entity_Id; + Scheme : Node_Id; + Stmts : List_Id; + + begin + -- Create the declaration of the flag which tracks the status of the + -- quantified expression. Generate: + + -- Flag : Boolean := (True | False); + + Flag := Make_Temporary (Loc, 'T', N); + + Append_To (Actions, + Make_Object_Declaration (Loc, + Defining_Identifier => Flag, + Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), + Expression => + New_Occurrence_Of (Boolean_Literals (For_All), Loc))); + + -- Construct the circuitry which tracks the status of the quantified + -- expression. Generate: + + -- if [not] Cond then + -- Flag := (False | True); + -- exit; + -- end if; + + Cond := Relocate_Node (Condition (N)); + + if For_All then + Cond := Make_Op_Not (Loc, Cond); + end if; + + Stmts := New_List ( + Make_Implicit_If_Statement (N, + Condition => Cond, + Then_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Flag, Loc), + Expression => + New_Occurrence_Of (Boolean_Literals (not For_All), Loc)), + Make_Exit_Statement (Loc)))); + + -- Build the loop equivalent of the quantified expression + + if Present (Iter_Spec) then + Scheme := + Make_Iteration_Scheme (Loc, + Iterator_Specification => Iter_Spec); + else + Scheme := + Make_Iteration_Scheme (Loc, + Loop_Parameter_Specification => Loop_Spec); + end if; + + Append_To (Actions, + Make_Loop_Statement (Loc, + Iteration_Scheme => Scheme, + Statements => Stmts, + End_Label => Empty)); + + -- Transform the quantified expression + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Expression => New_Occurrence_Of (Flag, Loc), + Actions => Actions)); + Analyze_And_Resolve (N, Standard_Boolean); + end Expand_N_Quantified_Expression; + + --------------------------------- + -- Expand_N_Selected_Component -- + --------------------------------- + + procedure Expand_N_Selected_Component (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Par : constant Node_Id := Parent (N); + P : constant Node_Id := Prefix (N); + S : constant Node_Id := Selector_Name (N); + Ptyp : Entity_Id := Underlying_Type (Etype (P)); + Disc : Entity_Id; + New_N : Node_Id; + Dcon : Elmt_Id; + Dval : Node_Id; + + function In_Left_Hand_Side (Comp : Node_Id) return Boolean; + -- Gigi needs a temporary for prefixes that depend on a discriminant, + -- unless the context of an assignment can provide size information. + -- Don't we have a general routine that does this??? + + function Is_Subtype_Declaration return Boolean; + -- The replacement of a discriminant reference by its value is required + -- if this is part of the initialization of an temporary generated by a + -- change of representation. This shows up as the construction of a + -- discriminant constraint for a subtype declared at the same point as + -- the entity in the prefix of the selected component. We recognize this + -- case when the context of the reference is: + -- subtype ST is T(Obj.D); + -- where the entity for Obj comes from source, and ST has the same sloc. + + ----------------------- + -- In_Left_Hand_Side -- + ----------------------- + + function In_Left_Hand_Side (Comp : Node_Id) return Boolean is + begin + return (Nkind (Parent (Comp)) = N_Assignment_Statement + and then Comp = Name (Parent (Comp))) + or else (Present (Parent (Comp)) + and then Nkind (Parent (Comp)) in N_Subexpr + and then In_Left_Hand_Side (Parent (Comp))); + end In_Left_Hand_Side; + + ----------------------------- + -- Is_Subtype_Declaration -- + ----------------------------- + + function Is_Subtype_Declaration return Boolean is + Par : constant Node_Id := Parent (N); + begin + return + Nkind (Par) = N_Index_Or_Discriminant_Constraint + and then Nkind (Parent (Parent (Par))) = N_Subtype_Declaration + and then Comes_From_Source (Entity (Prefix (N))) + and then Sloc (Par) = Sloc (Entity (Prefix (N))); + end Is_Subtype_Declaration; + + -- Start of processing for Expand_N_Selected_Component + + begin + -- Insert explicit dereference if required + + if Is_Access_Type (Ptyp) then + + -- First set prefix type to proper access type, in case it currently + -- has a private (non-access) view of this type. + + Set_Etype (P, Ptyp); + + Insert_Explicit_Dereference (P); + Analyze_And_Resolve (P, Designated_Type (Ptyp)); + + if Ekind (Etype (P)) = E_Private_Subtype + and then Is_For_Access_Subtype (Etype (P)) + then + Set_Etype (P, Base_Type (Etype (P))); + end if; + + Ptyp := Etype (P); + end if; + + -- Deal with discriminant check required + + if Do_Discriminant_Check (N) then + if Present (Discriminant_Checking_Func + (Original_Record_Component (Entity (S)))) + then + -- Present the discriminant checking function to the backend, so + -- that it can inline the call to the function. + + Add_Inlined_Body + (Discriminant_Checking_Func + (Original_Record_Component (Entity (S))), + N); + + -- Now reset the flag and generate the call + + Set_Do_Discriminant_Check (N, False); + Generate_Discriminant_Check (N); + + -- In the case of Unchecked_Union, no discriminant checking is + -- actually performed. + + else + Set_Do_Discriminant_Check (N, False); + end if; + end if; + + -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place + -- function, then additional actuals must be passed. + + if Is_Build_In_Place_Function_Call (P) then + Make_Build_In_Place_Call_In_Anonymous_Context (P); + + -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix + -- containing build-in-place function calls whose returned object covers + -- interface types. + + elsif Present (Unqual_BIP_Iface_Function_Call (P)) then + Make_Build_In_Place_Iface_Call_In_Anonymous_Context (P); + end if; + + -- Gigi cannot handle unchecked conversions that are the prefix of a + -- selected component with discriminants. This must be checked during + -- expansion, because during analysis the type of the selector is not + -- known at the point the prefix is analyzed. If the conversion is the + -- target of an assignment, then we cannot force the evaluation. + + if Nkind (Prefix (N)) = N_Unchecked_Type_Conversion + and then Has_Discriminants (Etype (N)) + and then not In_Left_Hand_Side (N) + then + Force_Evaluation (Prefix (N)); + end if; + + -- Remaining processing applies only if selector is a discriminant + + if Ekind (Entity (Selector_Name (N))) = E_Discriminant then + + -- If the selector is a discriminant of a constrained record type, + -- we may be able to rewrite the expression with the actual value + -- of the discriminant, a useful optimization in some cases. + + if Is_Record_Type (Ptyp) + and then Has_Discriminants (Ptyp) + and then Is_Constrained (Ptyp) + then + -- Do this optimization for discrete types only, and not for + -- access types (access discriminants get us into trouble). + + if not Is_Discrete_Type (Etype (N)) then + null; + + -- Don't do this on the left-hand side of an assignment statement. + -- Normally one would think that references like this would not + -- occur, but they do in generated code, and mean that we really + -- do want to assign the discriminant. + + elsif Nkind (Par) = N_Assignment_Statement + and then Name (Par) = N + then + null; + + -- Don't do this optimization for the prefix of an attribute or + -- the name of an object renaming declaration since these are + -- contexts where we do not want the value anyway. + + elsif (Nkind (Par) = N_Attribute_Reference + and then Prefix (Par) = N) + or else Is_Renamed_Object (N) + then + null; + + -- Don't do this optimization if we are within the code for a + -- discriminant check, since the whole point of such a check may + -- be to verify the condition on which the code below depends. + + elsif Is_In_Discriminant_Check (N) then + null; + + -- Green light to see if we can do the optimization. There is + -- still one condition that inhibits the optimization below but + -- now is the time to check the particular discriminant. + + else + -- Loop through discriminants to find the matching discriminant + -- constraint to see if we can copy it. + + Disc := First_Discriminant (Ptyp); + Dcon := First_Elmt (Discriminant_Constraint (Ptyp)); + Discr_Loop : while Present (Dcon) loop + Dval := Node (Dcon); + + -- Check if this is the matching discriminant and if the + -- discriminant value is simple enough to make sense to + -- copy. We don't want to copy complex expressions, and + -- indeed to do so can cause trouble (before we put in + -- this guard, a discriminant expression containing an + -- AND THEN was copied, causing problems for coverage + -- analysis tools). + + -- However, if the reference is part of the initialization + -- code generated for an object declaration, we must use + -- the discriminant value from the subtype constraint, + -- because the selected component may be a reference to the + -- object being initialized, whose discriminant is not yet + -- set. This only happens in complex cases involving changes + -- or representation. + + if Disc = Entity (Selector_Name (N)) + and then (Is_Entity_Name (Dval) + or else Compile_Time_Known_Value (Dval) + or else Is_Subtype_Declaration) + then + -- Here we have the matching discriminant. Check for + -- the case of a discriminant of a component that is + -- constrained by an outer discriminant, which cannot + -- be optimized away. + + if Denotes_Discriminant + (Dval, Check_Concurrent => True) + then + exit Discr_Loop; + + elsif Nkind (Original_Node (Dval)) = N_Selected_Component + and then + Denotes_Discriminant + (Selector_Name (Original_Node (Dval)), True) + then + exit Discr_Loop; + + -- Do not retrieve value if constraint is not static. It + -- is generally not useful, and the constraint may be a + -- rewritten outer discriminant in which case it is in + -- fact incorrect. + + elsif Is_Entity_Name (Dval) + and then + Nkind (Parent (Entity (Dval))) = N_Object_Declaration + and then Present (Expression (Parent (Entity (Dval)))) + and then not + Is_OK_Static_Expression + (Expression (Parent (Entity (Dval)))) + then + exit Discr_Loop; + + -- In the context of a case statement, the expression may + -- have the base type of the discriminant, and we need to + -- preserve the constraint to avoid spurious errors on + -- missing cases. + + elsif Nkind (Parent (N)) = N_Case_Statement + and then Etype (Dval) /= Etype (Disc) + then + Rewrite (N, + Make_Qualified_Expression (Loc, + Subtype_Mark => + New_Occurrence_Of (Etype (Disc), Loc), + Expression => + New_Copy_Tree (Dval))); + Analyze_And_Resolve (N, Etype (Disc)); + + -- In case that comes out as a static expression, + -- reset it (a selected component is never static). + + Set_Is_Static_Expression (N, False); + return; + + -- Otherwise we can just copy the constraint, but the + -- result is certainly not static. In some cases the + -- discriminant constraint has been analyzed in the + -- context of the original subtype indication, but for + -- itypes the constraint might not have been analyzed + -- yet, and this must be done now. + + else + Rewrite (N, New_Copy_Tree (Dval)); + Analyze_And_Resolve (N); + Set_Is_Static_Expression (N, False); + return; + end if; + end if; + + Next_Elmt (Dcon); + Next_Discriminant (Disc); + end loop Discr_Loop; + + -- Note: the above loop should always find a matching + -- discriminant, but if it does not, we just missed an + -- optimization due to some glitch (perhaps a previous + -- error), so ignore. + + end if; + end if; + + -- The only remaining processing is in the case of a discriminant of + -- a concurrent object, where we rewrite the prefix to denote the + -- corresponding record type. If the type is derived and has renamed + -- discriminants, use corresponding discriminant, which is the one + -- that appears in the corresponding record. + + if not Is_Concurrent_Type (Ptyp) then + return; + end if; + + Disc := Entity (Selector_Name (N)); + + if Is_Derived_Type (Ptyp) + and then Present (Corresponding_Discriminant (Disc)) + then + Disc := Corresponding_Discriminant (Disc); + end if; + + New_N := + Make_Selected_Component (Loc, + Prefix => + Unchecked_Convert_To (Corresponding_Record_Type (Ptyp), + New_Copy_Tree (P)), + Selector_Name => Make_Identifier (Loc, Chars (Disc))); + + Rewrite (N, New_N); + Analyze (N); + end if; + + -- Set Atomic_Sync_Required if necessary for atomic component + + if Nkind (N) = N_Selected_Component then + declare + E : constant Entity_Id := Entity (Selector_Name (N)); + Set : Boolean; + + begin + -- If component is atomic, but type is not, setting depends on + -- disable/enable state for the component. + + if Is_Atomic (E) and then not Is_Atomic (Etype (E)) then + Set := not Atomic_Synchronization_Disabled (E); + + -- If component is not atomic, but its type is atomic, setting + -- depends on disable/enable state for the type. + + elsif not Is_Atomic (E) and then Is_Atomic (Etype (E)) then + Set := not Atomic_Synchronization_Disabled (Etype (E)); + + -- If both component and type are atomic, we disable if either + -- component or its type have sync disabled. + + elsif Is_Atomic (E) and then Is_Atomic (Etype (E)) then + Set := (not Atomic_Synchronization_Disabled (E)) + and then + (not Atomic_Synchronization_Disabled (Etype (E))); + + else + Set := False; + end if; + + -- Set flag if required + + if Set then + Activate_Atomic_Synchronization (N); + end if; + end; + end if; + end Expand_N_Selected_Component; + + -------------------- + -- Expand_N_Slice -- + -------------------- + + procedure Expand_N_Slice (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + + function Is_Procedure_Actual (N : Node_Id) return Boolean; + -- Check whether the argument is an actual for a procedure call, in + -- which case the expansion of a bit-packed slice is deferred until the + -- call itself is expanded. The reason this is required is that we might + -- have an IN OUT or OUT parameter, and the copy out is essential, and + -- that copy out would be missed if we created a temporary here in + -- Expand_N_Slice. Note that we don't bother to test specifically for an + -- IN OUT or OUT mode parameter, since it is a bit tricky to do, and it + -- is harmless to defer expansion in the IN case, since the call + -- processing will still generate the appropriate copy in operation, + -- which will take care of the slice. + + procedure Make_Temporary_For_Slice; + -- Create a named variable for the value of the slice, in cases where + -- the back end cannot handle it properly, e.g. when packed types or + -- unaligned slices are involved. + + ------------------------- + -- Is_Procedure_Actual -- + ------------------------- + + function Is_Procedure_Actual (N : Node_Id) return Boolean is + Par : Node_Id := Parent (N); + + begin + loop + -- If our parent is a procedure call we can return + + if Nkind (Par) = N_Procedure_Call_Statement then + return True; + + -- If our parent is a type conversion, keep climbing the tree, + -- since a type conversion can be a procedure actual. Also keep + -- climbing if parameter association or a qualified expression, + -- since these are additional cases that do can appear on + -- procedure actuals. + + elsif Nkind_In (Par, N_Type_Conversion, + N_Parameter_Association, + N_Qualified_Expression) + then + Par := Parent (Par); + + -- Any other case is not what we are looking for + + else + return False; + end if; + end loop; + end Is_Procedure_Actual; + + ------------------------------ + -- Make_Temporary_For_Slice -- + ------------------------------ + + procedure Make_Temporary_For_Slice is + Ent : constant Entity_Id := Make_Temporary (Loc, 'T', N); + Decl : Node_Id; + + begin + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => New_Occurrence_Of (Typ, Loc)); + + Set_No_Initialization (Decl); + + Insert_Actions (N, New_List ( + Decl, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Ent, Loc), + Expression => Relocate_Node (N)))); + + Rewrite (N, New_Occurrence_Of (Ent, Loc)); + Analyze_And_Resolve (N, Typ); + end Make_Temporary_For_Slice; + + -- Local variables + + Pref : constant Node_Id := Prefix (N); + Pref_Typ : Entity_Id := Etype (Pref); + + -- Start of processing for Expand_N_Slice + + begin + -- Special handling for access types + + if Is_Access_Type (Pref_Typ) then + Pref_Typ := Designated_Type (Pref_Typ); + + Rewrite (Pref, + Make_Explicit_Dereference (Sloc (N), + Prefix => Relocate_Node (Pref))); + + Analyze_And_Resolve (Pref, Pref_Typ); + end if; + + -- Ada 2005 (AI-318-02): If the prefix is a call to a build-in-place + -- function, then additional actuals must be passed. + + if Is_Build_In_Place_Function_Call (Pref) then + Make_Build_In_Place_Call_In_Anonymous_Context (Pref); + + -- Ada 2005 (AI-318-02): Specialization of the previous case for prefix + -- containing build-in-place function calls whose returned object covers + -- interface types. + + elsif Present (Unqual_BIP_Iface_Function_Call (Pref)) then + Make_Build_In_Place_Iface_Call_In_Anonymous_Context (Pref); + end if; + + -- The remaining case to be handled is packed slices. We can leave + -- packed slices as they are in the following situations: + + -- 1. Right or left side of an assignment (we can handle this + -- situation correctly in the assignment statement expansion). + + -- 2. Prefix of indexed component (the slide is optimized away in this + -- case, see the start of Expand_N_Slice.) + + -- 3. Object renaming declaration, since we want the name of the + -- slice, not the value. + + -- 4. Argument to procedure call, since copy-in/copy-out handling may + -- be required, and this is handled in the expansion of call + -- itself. + + -- 5. Prefix of an address attribute (this is an error which is caught + -- elsewhere, and the expansion would interfere with generating the + -- error message). + + if not Is_Packed (Typ) then + + -- Apply transformation for actuals of a function call, where + -- Expand_Actuals is not used. + + if Nkind (Parent (N)) = N_Function_Call + and then Is_Possibly_Unaligned_Slice (N) + then + Make_Temporary_For_Slice; + end if; + + elsif Nkind (Parent (N)) = N_Assignment_Statement + or else (Nkind (Parent (Parent (N))) = N_Assignment_Statement + and then Parent (N) = Name (Parent (Parent (N)))) + then + return; + + elsif Nkind (Parent (N)) = N_Indexed_Component + or else Is_Renamed_Object (N) + or else Is_Procedure_Actual (N) + then + return; + + elsif Nkind (Parent (N)) = N_Attribute_Reference + and then Attribute_Name (Parent (N)) = Name_Address + then + return; + + else + Make_Temporary_For_Slice; + end if; + end Expand_N_Slice; + + ------------------------------ + -- Expand_N_Type_Conversion -- + ------------------------------ + + procedure Expand_N_Type_Conversion (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Operand : constant Node_Id := Expression (N); + Target_Type : constant Entity_Id := Etype (N); + Operand_Type : Entity_Id := Etype (Operand); + + procedure Handle_Changed_Representation; + -- This is called in the case of record and array type conversions to + -- see if there is a change of representation to be handled. Change of + -- representation is actually handled at the assignment statement level, + -- and what this procedure does is rewrite node N conversion as an + -- assignment to temporary. If there is no change of representation, + -- then the conversion node is unchanged. + + procedure Raise_Accessibility_Error; + -- Called when we know that an accessibility check will fail. Rewrites + -- node N to an appropriate raise statement and outputs warning msgs. + -- The Etype of the raise node is set to Target_Type. Note that in this + -- case the rest of the processing should be skipped (i.e. the call to + -- this procedure will be followed by "goto Done"). + + procedure Real_Range_Check; + -- Handles generation of range check for real target value + + function Has_Extra_Accessibility (Id : Entity_Id) return Boolean; + -- True iff Present (Effective_Extra_Accessibility (Id)) successfully + -- evaluates to True. + + ----------------------------------- + -- Handle_Changed_Representation -- + ----------------------------------- + + procedure Handle_Changed_Representation is + Temp : Entity_Id; + Decl : Node_Id; + Odef : Node_Id; + N_Ix : Node_Id; + Cons : List_Id; + + begin + -- Nothing else to do if no change of representation + + if Same_Representation (Operand_Type, Target_Type) then + return; + + -- The real change of representation work is done by the assignment + -- statement processing. So if this type conversion is appearing as + -- the expression of an assignment statement, nothing needs to be + -- done to the conversion. + + elsif Nkind (Parent (N)) = N_Assignment_Statement then + return; + + -- Otherwise we need to generate a temporary variable, and do the + -- change of representation assignment into that temporary variable. + -- The conversion is then replaced by a reference to this variable. + + else + Cons := No_List; + + -- If type is unconstrained we have to add a constraint, copied + -- from the actual value of the left-hand side. + + if not Is_Constrained (Target_Type) then + if Has_Discriminants (Operand_Type) then + + -- A change of representation can only apply to untagged + -- types. We need to build the constraint that applies to + -- the target type, using the constraints of the operand. + -- The analysis is complicated if there are both inherited + -- discriminants and constrained discriminants. + -- We iterate over the discriminants of the target, and + -- find the discriminant of the same name: + + -- a) If there is a corresponding discriminant in the object + -- then the value is a selected component of the operand. + + -- b) Otherwise the value of a constrained discriminant is + -- found in the stored constraint of the operand. + + declare + Stored : constant Elist_Id := + Stored_Constraint (Operand_Type); + + Elmt : Elmt_Id; + + Disc_O : Entity_Id; + -- Discriminant of the operand type. Its value in the + -- object is captured in a selected component. + + Disc_S : Entity_Id; + -- Stored discriminant of the operand. If present, it + -- corresponds to a constrained discriminant of the + -- parent type. + + Disc_T : Entity_Id; + -- Discriminant of the target type + + begin + Disc_T := First_Discriminant (Target_Type); + Disc_O := First_Discriminant (Operand_Type); + Disc_S := First_Stored_Discriminant (Operand_Type); + + if Present (Stored) then + Elmt := First_Elmt (Stored); + end if; + + Cons := New_List; + while Present (Disc_T) loop + if Present (Disc_O) + and then Chars (Disc_T) = Chars (Disc_O) + then + Append_To (Cons, + Make_Selected_Component (Loc, + Prefix => + Duplicate_Subexpr_Move_Checks (Operand), + Selector_Name => + Make_Identifier (Loc, Chars (Disc_O)))); + Next_Discriminant (Disc_O); + + elsif Present (Disc_S) then + Append_To (Cons, New_Copy_Tree (Node (Elmt))); + Next_Elmt (Elmt); + end if; + + Next_Discriminant (Disc_T); + end loop; + end; + + elsif Is_Array_Type (Operand_Type) then + N_Ix := First_Index (Target_Type); + Cons := New_List; + + for J in 1 .. Number_Dimensions (Operand_Type) loop + + -- We convert the bounds explicitly. We use an unchecked + -- conversion because bounds checks are done elsewhere. + + Append_To (Cons, + Make_Range (Loc, + Low_Bound => + Unchecked_Convert_To (Etype (N_Ix), + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr_No_Checks + (Operand, Name_Req => True), + Attribute_Name => Name_First, + Expressions => New_List ( + Make_Integer_Literal (Loc, J)))), + + High_Bound => + Unchecked_Convert_To (Etype (N_Ix), + Make_Attribute_Reference (Loc, + Prefix => + Duplicate_Subexpr_No_Checks + (Operand, Name_Req => True), + Attribute_Name => Name_Last, + Expressions => New_List ( + Make_Integer_Literal (Loc, J)))))); + + Next_Index (N_Ix); + end loop; + end if; + end if; + + Odef := New_Occurrence_Of (Target_Type, Loc); + + if Present (Cons) then + Odef := + Make_Subtype_Indication (Loc, + Subtype_Mark => Odef, + Constraint => + Make_Index_Or_Discriminant_Constraint (Loc, + Constraints => Cons)); + end if; + + Temp := Make_Temporary (Loc, 'C'); + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => Odef); + + Set_No_Initialization (Decl, True); + + -- Insert required actions. It is essential to suppress checks + -- since we have suppressed default initialization, which means + -- that the variable we create may have no discriminants. + + Insert_Actions (N, + New_List ( + Decl, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Temp, Loc), + Expression => Relocate_Node (N))), + Suppress => All_Checks); + + Rewrite (N, New_Occurrence_Of (Temp, Loc)); + return; + end if; + end Handle_Changed_Representation; + + ------------------------------- + -- Raise_Accessibility_Error -- + ------------------------------- + + procedure Raise_Accessibility_Error is + begin + Error_Msg_Warn := SPARK_Mode /= On; + Rewrite (N, + Make_Raise_Program_Error (Sloc (N), + Reason => PE_Accessibility_Check_Failed)); + Set_Etype (N, Target_Type); + + Error_Msg_N ("<<accessibility check failure", N); + Error_Msg_NE ("\<<& [", N, Standard_Program_Error); + end Raise_Accessibility_Error; + + ---------------------- + -- Real_Range_Check -- + ---------------------- + + -- Case of conversions to floating-point or fixed-point. If range checks + -- are enabled and the target type has a range constraint, we convert: + + -- typ (x) + + -- to + + -- Tnn : typ'Base := typ'Base (x); + -- [constraint_error when Tnn < typ'First or else Tnn > typ'Last] + -- Tnn + + -- This is necessary when there is a conversion of integer to float or + -- to fixed-point to ensure that the correct checks are made. It is not + -- necessary for float to float where it is enough to simply set the + -- Do_Range_Check flag. + + procedure Real_Range_Check is + Btyp : constant Entity_Id := Base_Type (Target_Type); + Lo : constant Node_Id := Type_Low_Bound (Target_Type); + Hi : constant Node_Id := Type_High_Bound (Target_Type); + Xtyp : constant Entity_Id := Etype (Operand); + Conv : Node_Id; + Tnn : Entity_Id; + + begin + -- Nothing to do if conversion was rewritten + + if Nkind (N) /= N_Type_Conversion then + return; + end if; + + -- Nothing to do if range checks suppressed, or target has the same + -- range as the base type (or is the base type). + + if Range_Checks_Suppressed (Target_Type) + or else (Lo = Type_Low_Bound (Btyp) + and then + Hi = Type_High_Bound (Btyp)) + then + return; + end if; + + -- Nothing to do if expression is an entity on which checks have been + -- suppressed. + + if Is_Entity_Name (Operand) + and then Range_Checks_Suppressed (Entity (Operand)) + then + return; + end if; + + -- Nothing to do if bounds are all static and we can tell that the + -- expression is within the bounds of the target. Note that if the + -- operand is of an unconstrained floating-point type, then we do + -- not trust it to be in range (might be infinite) + + declare + S_Lo : constant Node_Id := Type_Low_Bound (Xtyp); + S_Hi : constant Node_Id := Type_High_Bound (Xtyp); + + begin + if (not Is_Floating_Point_Type (Xtyp) + or else Is_Constrained (Xtyp)) + and then Compile_Time_Known_Value (S_Lo) + and then Compile_Time_Known_Value (S_Hi) + and then Compile_Time_Known_Value (Hi) + and then Compile_Time_Known_Value (Lo) + then + declare + D_Lov : constant Ureal := Expr_Value_R (Lo); + D_Hiv : constant Ureal := Expr_Value_R (Hi); + S_Lov : Ureal; + S_Hiv : Ureal; + + begin + if Is_Real_Type (Xtyp) then + S_Lov := Expr_Value_R (S_Lo); + S_Hiv := Expr_Value_R (S_Hi); + else + S_Lov := UR_From_Uint (Expr_Value (S_Lo)); + S_Hiv := UR_From_Uint (Expr_Value (S_Hi)); + end if; + + if D_Hiv > D_Lov + and then S_Lov >= D_Lov + and then S_Hiv <= D_Hiv + then + -- Unset the range check flag on the current value of + -- Expression (N), since the captured Operand may have + -- been rewritten (such as for the case of a conversion + -- to a fixed-point type). + + Set_Do_Range_Check (Expression (N), False); + + return; + end if; + end; + end if; + end; + + -- For float to float conversions, we are done + + if Is_Floating_Point_Type (Xtyp) + and then + Is_Floating_Point_Type (Btyp) + then + return; + end if; + + -- Otherwise rewrite the conversion as described above + + Conv := Relocate_Node (N); + Rewrite (Subtype_Mark (Conv), New_Occurrence_Of (Btyp, Loc)); + Set_Etype (Conv, Btyp); + + -- Enable overflow except for case of integer to float conversions, + -- where it is never required, since we can never have overflow in + -- this case. + + if not Is_Integer_Type (Etype (Operand)) then + Enable_Overflow_Check (Conv); + end if; + + Tnn := Make_Temporary (Loc, 'T', Conv); + + Insert_Actions (N, New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => Tnn, + Object_Definition => New_Occurrence_Of (Btyp, Loc), + Constant_Present => True, + Expression => Conv), + + Make_Raise_Constraint_Error (Loc, + Condition => + Make_Or_Else (Loc, + Left_Opnd => + Make_Op_Lt (Loc, + Left_Opnd => New_Occurrence_Of (Tnn, Loc), + Right_Opnd => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_First, + Prefix => + New_Occurrence_Of (Target_Type, Loc))), + + Right_Opnd => + Make_Op_Gt (Loc, + Left_Opnd => New_Occurrence_Of (Tnn, Loc), + Right_Opnd => + Make_Attribute_Reference (Loc, + Attribute_Name => Name_Last, + Prefix => + New_Occurrence_Of (Target_Type, Loc)))), + Reason => CE_Range_Check_Failed))); + + Rewrite (N, New_Occurrence_Of (Tnn, Loc)); + Analyze_And_Resolve (N, Btyp); + end Real_Range_Check; + + ----------------------------- + -- Has_Extra_Accessibility -- + ----------------------------- + + -- Returns true for a formal of an anonymous access type or for + -- an Ada 2012-style stand-alone object of an anonymous access type. + + function Has_Extra_Accessibility (Id : Entity_Id) return Boolean is + begin + if Is_Formal (Id) or else Ekind_In (Id, E_Constant, E_Variable) then + return Present (Effective_Extra_Accessibility (Id)); + else + return False; + end if; + end Has_Extra_Accessibility; + + -- Start of processing for Expand_N_Type_Conversion + + begin + -- First remove check marks put by the semantic analysis on the type + -- conversion between array types. We need these checks, and they will + -- be generated by this expansion routine, but we do not depend on these + -- flags being set, and since we do intend to expand the checks in the + -- front end, we don't want them on the tree passed to the back end. + + if Is_Array_Type (Target_Type) then + if Is_Constrained (Target_Type) then + Set_Do_Length_Check (N, False); + else + Set_Do_Range_Check (Operand, False); + end if; + end if; + + -- Nothing at all to do if conversion is to the identical type so remove + -- the conversion completely, it is useless, except that it may carry + -- an Assignment_OK attribute, which must be propagated to the operand. + + if Operand_Type = Target_Type then + if Assignment_OK (N) then + Set_Assignment_OK (Operand); + end if; + + Rewrite (N, Relocate_Node (Operand)); + goto Done; + end if; + + -- Nothing to do if this is the second argument of read. This is a + -- "backwards" conversion that will be handled by the specialized code + -- in attribute processing. + + if Nkind (Parent (N)) = N_Attribute_Reference + and then Attribute_Name (Parent (N)) = Name_Read + and then Next (First (Expressions (Parent (N)))) = N + then + goto Done; + end if; + + -- Check for case of converting to a type that has an invariant + -- associated with it. This requires an invariant check. We insert + -- a call: + + -- invariant_check (typ (expr)) + + -- in the code, after removing side effects from the expression. + -- This is clearer than replacing the conversion into an expression + -- with actions, because the context may impose additional actions + -- (tag checks, membership tests, etc.) that conflict with this + -- rewriting (used previously). + + -- Note: the Comes_From_Source check, and then the resetting of this + -- flag prevents what would otherwise be an infinite recursion. + + if Has_Invariants (Target_Type) + and then Present (Invariant_Procedure (Target_Type)) + and then Comes_From_Source (N) + then + Set_Comes_From_Source (N, False); + Remove_Side_Effects (N); + Insert_Action (N, Make_Invariant_Call (Duplicate_Subexpr (N))); + goto Done; + end if; + + -- Here if we may need to expand conversion + + -- If the operand of the type conversion is an arithmetic operation on + -- signed integers, and the based type of the signed integer type in + -- question is smaller than Standard.Integer, we promote both of the + -- operands to type Integer. + + -- For example, if we have + + -- target-type (opnd1 + opnd2) + + -- and opnd1 and opnd2 are of type short integer, then we rewrite + -- this as: + + -- target-type (integer(opnd1) + integer(opnd2)) + + -- We do this because we are always allowed to compute in a larger type + -- if we do the right thing with the result, and in this case we are + -- going to do a conversion which will do an appropriate check to make + -- sure that things are in range of the target type in any case. This + -- avoids some unnecessary intermediate overflows. + + -- We might consider a similar transformation in the case where the + -- target is a real type or a 64-bit integer type, and the operand + -- is an arithmetic operation using a 32-bit integer type. However, + -- we do not bother with this case, because it could cause significant + -- inefficiencies on 32-bit machines. On a 64-bit machine it would be + -- much cheaper, but we don't want different behavior on 32-bit and + -- 64-bit machines. Note that the exclusion of the 64-bit case also + -- handles the configurable run-time cases where 64-bit arithmetic + -- may simply be unavailable. + + -- Note: this circuit is partially redundant with respect to the circuit + -- in Checks.Apply_Arithmetic_Overflow_Check, but we catch more cases in + -- the processing here. Also we still need the Checks circuit, since we + -- have to be sure not to generate junk overflow checks in the first + -- place, since it would be trick to remove them here. + + if Integer_Promotion_Possible (N) then + + -- All conditions met, go ahead with transformation + + declare + Opnd : Node_Id; + L, R : Node_Id; + + begin + R := + Make_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Standard_Integer, Loc), + Expression => Relocate_Node (Right_Opnd (Operand))); + + Opnd := New_Op_Node (Nkind (Operand), Loc); + Set_Right_Opnd (Opnd, R); + + if Nkind (Operand) in N_Binary_Op then + L := + Make_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Standard_Integer, Loc), + Expression => Relocate_Node (Left_Opnd (Operand))); + + Set_Left_Opnd (Opnd, L); + end if; + + Rewrite (N, + Make_Type_Conversion (Loc, + Subtype_Mark => Relocate_Node (Subtype_Mark (N)), + Expression => Opnd)); + + Analyze_And_Resolve (N, Target_Type); + goto Done; + end; + end if; + + -- Do validity check if validity checking operands + + if Validity_Checks_On and Validity_Check_Operands then + Ensure_Valid (Operand); + end if; + + -- Special case of converting from non-standard boolean type + + if Is_Boolean_Type (Operand_Type) + and then (Nonzero_Is_True (Operand_Type)) + then + Adjust_Condition (Operand); + Set_Etype (Operand, Standard_Boolean); + Operand_Type := Standard_Boolean; + end if; + + -- Case of converting to an access type + + if Is_Access_Type (Target_Type) then + + -- If this type conversion was internally generated by the front end + -- to displace the pointer to the object to reference an interface + -- type and the original node was an Unrestricted_Access attribute, + -- then skip applying accessibility checks (because, according to the + -- GNAT Reference Manual, this attribute is similar to 'Access except + -- that all accessibility and aliased view checks are omitted). + + if not Comes_From_Source (N) + and then Is_Interface (Designated_Type (Target_Type)) + and then Nkind (Original_Node (N)) = N_Attribute_Reference + and then Attribute_Name (Original_Node (N)) = + Name_Unrestricted_Access + then + null; + + -- Apply an accessibility check when the conversion operand is an + -- access parameter (or a renaming thereof), unless conversion was + -- expanded from an Unchecked_ or Unrestricted_Access attribute, + -- or for the actual of a class-wide interface parameter. Note that + -- other checks may still need to be applied below (such as tagged + -- type checks). + + elsif Is_Entity_Name (Operand) + and then Has_Extra_Accessibility (Entity (Operand)) + and then Ekind (Etype (Operand)) = E_Anonymous_Access_Type + and then (Nkind (Original_Node (N)) /= N_Attribute_Reference + or else Attribute_Name (Original_Node (N)) = Name_Access) + then + if not Comes_From_Source (N) + and then Nkind_In (Parent (N), N_Function_Call, + N_Procedure_Call_Statement) + and then Is_Interface (Designated_Type (Target_Type)) + and then Is_Class_Wide_Type (Designated_Type (Target_Type)) + then + null; + + else + Apply_Accessibility_Check + (Operand, Target_Type, Insert_Node => Operand); + end if; + + -- If the level of the operand type is statically deeper than the + -- level of the target type, then force Program_Error. Note that this + -- can only occur for cases where the attribute is within the body of + -- an instantiation, otherwise the conversion will already have been + -- rejected as illegal. + + -- Note: warnings are issued by the analyzer for the instance cases + + elsif In_Instance_Body + + -- The case where the target type is an anonymous access type of + -- a discriminant is excluded, because the level of such a type + -- depends on the context and currently the level returned for such + -- types is zero, resulting in warnings about about check failures + -- in certain legal cases involving class-wide interfaces as the + -- designated type (some cases, such as return statements, are + -- checked at run time, but not clear if these are handled right + -- in general, see 3.10.2(12/2-12.5/3) ???). + + and then + not (Ekind (Target_Type) = E_Anonymous_Access_Type + and then Present (Associated_Node_For_Itype (Target_Type)) + and then Nkind (Associated_Node_For_Itype (Target_Type)) = + N_Discriminant_Specification) + and then + Type_Access_Level (Operand_Type) > Type_Access_Level (Target_Type) + then + Raise_Accessibility_Error; + goto Done; + + -- When the operand is a selected access discriminant the check needs + -- to be made against the level of the object denoted by the prefix + -- of the selected name. Force Program_Error for this case as well + -- (this accessibility violation can only happen if within the body + -- of an instantiation). + + elsif In_Instance_Body + and then Ekind (Operand_Type) = E_Anonymous_Access_Type + and then Nkind (Operand) = N_Selected_Component + and then Object_Access_Level (Operand) > + Type_Access_Level (Target_Type) + then + Raise_Accessibility_Error; + goto Done; + end if; + end if; + + -- Case of conversions of tagged types and access to tagged types + + -- When needed, that is to say when the expression is class-wide, Add + -- runtime a tag check for (strict) downward conversion by using the + -- membership test, generating: + + -- [constraint_error when Operand not in Target_Type'Class] + + -- or in the access type case + + -- [constraint_error + -- when Operand /= null + -- and then Operand.all not in + -- Designated_Type (Target_Type)'Class] + + if (Is_Access_Type (Target_Type) + and then Is_Tagged_Type (Designated_Type (Target_Type))) + or else Is_Tagged_Type (Target_Type) + then + -- Do not do any expansion in the access type case if the parent is a + -- renaming, since this is an error situation which will be caught by + -- Sem_Ch8, and the expansion can interfere with this error check. + + if Is_Access_Type (Target_Type) and then Is_Renamed_Object (N) then + goto Done; + end if; + + -- Otherwise, proceed with processing tagged conversion + + Tagged_Conversion : declare + Actual_Op_Typ : Entity_Id; + Actual_Targ_Typ : Entity_Id; + Make_Conversion : Boolean := False; + Root_Op_Typ : Entity_Id; + + procedure Make_Tag_Check (Targ_Typ : Entity_Id); + -- Create a membership check to test whether Operand is a member + -- of Targ_Typ. If the original Target_Type is an access, include + -- a test for null value. The check is inserted at N. + + -------------------- + -- Make_Tag_Check -- + -------------------- + + procedure Make_Tag_Check (Targ_Typ : Entity_Id) is + Cond : Node_Id; + + begin + -- Generate: + -- [Constraint_Error + -- when Operand /= null + -- and then Operand.all not in Targ_Typ] + + if Is_Access_Type (Target_Type) then + Cond := + Make_And_Then (Loc, + Left_Opnd => + Make_Op_Ne (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), + Right_Opnd => Make_Null (Loc)), + + Right_Opnd => + Make_Not_In (Loc, + Left_Opnd => + Make_Explicit_Dereference (Loc, + Prefix => Duplicate_Subexpr_No_Checks (Operand)), + Right_Opnd => New_Occurrence_Of (Targ_Typ, Loc))); + + -- Generate: + -- [Constraint_Error when Operand not in Targ_Typ] + + else + Cond := + Make_Not_In (Loc, + Left_Opnd => Duplicate_Subexpr_No_Checks (Operand), + Right_Opnd => New_Occurrence_Of (Targ_Typ, Loc)); + end if; + + Insert_Action (N, + Make_Raise_Constraint_Error (Loc, + Condition => Cond, + Reason => CE_Tag_Check_Failed), + Suppress => All_Checks); + end Make_Tag_Check; + + -- Start of processing for Tagged_Conversion + + begin + -- Handle entities from the limited view + + if Is_Access_Type (Operand_Type) then + Actual_Op_Typ := + Available_View (Designated_Type (Operand_Type)); + else + Actual_Op_Typ := Operand_Type; + end if; + + if Is_Access_Type (Target_Type) then + Actual_Targ_Typ := + Available_View (Designated_Type (Target_Type)); + else + Actual_Targ_Typ := Target_Type; + end if; + + Root_Op_Typ := Root_Type (Actual_Op_Typ); + + -- Ada 2005 (AI-251): Handle interface type conversion + + if Is_Interface (Actual_Op_Typ) + or else + Is_Interface (Actual_Targ_Typ) + then + Expand_Interface_Conversion (N); + goto Done; + end if; + + if not Tag_Checks_Suppressed (Actual_Targ_Typ) then + + -- Create a runtime tag check for a downward class-wide type + -- conversion. + + if Is_Class_Wide_Type (Actual_Op_Typ) + and then Actual_Op_Typ /= Actual_Targ_Typ + and then Root_Op_Typ /= Actual_Targ_Typ + and then Is_Ancestor (Root_Op_Typ, Actual_Targ_Typ, + Use_Full_View => True) + then + Make_Tag_Check (Class_Wide_Type (Actual_Targ_Typ)); + Make_Conversion := True; + end if; + + -- AI05-0073: If the result subtype of the function is defined + -- by an access_definition designating a specific tagged type + -- T, a check is made that the result value is null or the tag + -- of the object designated by the result value identifies T. + -- Constraint_Error is raised if this check fails. + + if Nkind (Parent (N)) = N_Simple_Return_Statement then + declare + Func : Entity_Id; + Func_Typ : Entity_Id; + + begin + -- Climb scope stack looking for the enclosing function + + Func := Current_Scope; + while Present (Func) + and then Ekind (Func) /= E_Function + loop + Func := Scope (Func); + end loop; + + -- The function's return subtype must be defined using + -- an access definition. + + if Nkind (Result_Definition (Parent (Func))) = + N_Access_Definition + then + Func_Typ := Directly_Designated_Type (Etype (Func)); + + -- The return subtype denotes a specific tagged type, + -- in other words, a non class-wide type. + + if Is_Tagged_Type (Func_Typ) + and then not Is_Class_Wide_Type (Func_Typ) + then + Make_Tag_Check (Actual_Targ_Typ); + Make_Conversion := True; + end if; + end if; + end; + end if; + + -- We have generated a tag check for either a class-wide type + -- conversion or for AI05-0073. + + if Make_Conversion then + declare + Conv : Node_Id; + begin + Conv := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Target_Type, Loc), + Expression => Relocate_Node (Expression (N))); + Rewrite (N, Conv); + Analyze_And_Resolve (N, Target_Type); + end; + end if; + end if; + end Tagged_Conversion; + + -- Case of other access type conversions + + elsif Is_Access_Type (Target_Type) then + Apply_Constraint_Check (Operand, Target_Type); + + -- Case of conversions from a fixed-point type + + -- These conversions require special expansion and processing, found in + -- the Exp_Fixd package. We ignore cases where Conversion_OK is set, + -- since from a semantic point of view, these are simple integer + -- conversions, which do not need further processing. + + elsif Is_Fixed_Point_Type (Operand_Type) + and then not Conversion_OK (N) + then + -- We should never see universal fixed at this case, since the + -- expansion of the constituent divide or multiply should have + -- eliminated the explicit mention of universal fixed. + + pragma Assert (Operand_Type /= Universal_Fixed); + + -- Check for special case of the conversion to universal real that + -- occurs as a result of the use of a round attribute. In this case, + -- the real type for the conversion is taken from the target type of + -- the Round attribute and the result must be marked as rounded. + + if Target_Type = Universal_Real + and then Nkind (Parent (N)) = N_Attribute_Reference + and then Attribute_Name (Parent (N)) = Name_Round + then + Set_Rounded_Result (N); + Set_Etype (N, Etype (Parent (N))); + end if; + + -- Otherwise do correct fixed-conversion, but skip these if the + -- Conversion_OK flag is set, because from a semantic point of view + -- these are simple integer conversions needing no further processing + -- (the backend will simply treat them as integers). + + if not Conversion_OK (N) then + if Is_Fixed_Point_Type (Etype (N)) then + Expand_Convert_Fixed_To_Fixed (N); + Real_Range_Check; + + elsif Is_Integer_Type (Etype (N)) then + Expand_Convert_Fixed_To_Integer (N); + + else + pragma Assert (Is_Floating_Point_Type (Etype (N))); + Expand_Convert_Fixed_To_Float (N); + Real_Range_Check; + end if; + end if; + + -- Case of conversions to a fixed-point type + + -- These conversions require special expansion and processing, found in + -- the Exp_Fixd package. Again, ignore cases where Conversion_OK is set, + -- since from a semantic point of view, these are simple integer + -- conversions, which do not need further processing. + + elsif Is_Fixed_Point_Type (Target_Type) + and then not Conversion_OK (N) + then + if Is_Integer_Type (Operand_Type) then + Expand_Convert_Integer_To_Fixed (N); + Real_Range_Check; + else + pragma Assert (Is_Floating_Point_Type (Operand_Type)); + Expand_Convert_Float_To_Fixed (N); + Real_Range_Check; + end if; + + -- Case of float-to-integer conversions + + -- We also handle float-to-fixed conversions with Conversion_OK set + -- since semantically the fixed-point target is treated as though it + -- were an integer in such cases. + + elsif Is_Floating_Point_Type (Operand_Type) + and then + (Is_Integer_Type (Target_Type) + or else + (Is_Fixed_Point_Type (Target_Type) and then Conversion_OK (N))) + then + -- One more check here, gcc is still not able to do conversions of + -- this type with proper overflow checking, and so gigi is doing an + -- approximation of what is required by doing floating-point compares + -- with the end-point. But that can lose precision in some cases, and + -- give a wrong result. Converting the operand to Universal_Real is + -- helpful, but still does not catch all cases with 64-bit integers + -- on targets with only 64-bit floats. + + -- The above comment seems obsoleted by Apply_Float_Conversion_Check + -- Can this code be removed ??? + + if Do_Range_Check (Operand) then + Rewrite (Operand, + Make_Type_Conversion (Loc, + Subtype_Mark => + New_Occurrence_Of (Universal_Real, Loc), + Expression => + Relocate_Node (Operand))); + + Set_Etype (Operand, Universal_Real); + Enable_Range_Check (Operand); + Set_Do_Range_Check (Expression (Operand), False); + end if; + + -- Case of array conversions + + -- Expansion of array conversions, add required length/range checks but + -- only do this if there is no change of representation. For handling of + -- this case, see Handle_Changed_Representation. + + elsif Is_Array_Type (Target_Type) then + if Is_Constrained (Target_Type) then + Apply_Length_Check (Operand, Target_Type); + else + Apply_Range_Check (Operand, Target_Type); + end if; + + Handle_Changed_Representation; + + -- Case of conversions of discriminated types + + -- Add required discriminant checks if target is constrained. Again this + -- change is skipped if we have a change of representation. + + elsif Has_Discriminants (Target_Type) + and then Is_Constrained (Target_Type) + then + Apply_Discriminant_Check (Operand, Target_Type); + Handle_Changed_Representation; + + -- Case of all other record conversions. The only processing required + -- is to check for a change of representation requiring the special + -- assignment processing. + + elsif Is_Record_Type (Target_Type) then + + -- Ada 2005 (AI-216): Program_Error is raised when converting from + -- a derived Unchecked_Union type to an unconstrained type that is + -- not Unchecked_Union if the operand lacks inferable discriminants. + + if Is_Derived_Type (Operand_Type) + and then Is_Unchecked_Union (Base_Type (Operand_Type)) + and then not Is_Constrained (Target_Type) + and then not Is_Unchecked_Union (Base_Type (Target_Type)) + and then not Has_Inferable_Discriminants (Operand) + then + -- To prevent Gigi from generating illegal code, we generate a + -- Program_Error node, but we give it the target type of the + -- conversion (is this requirement documented somewhere ???) + + declare + PE : constant Node_Id := Make_Raise_Program_Error (Loc, + Reason => PE_Unchecked_Union_Restriction); + + begin + Set_Etype (PE, Target_Type); + Rewrite (N, PE); + + end; + else + Handle_Changed_Representation; + end if; + + -- Case of conversions of enumeration types + + elsif Is_Enumeration_Type (Target_Type) then + + -- Special processing is required if there is a change of + -- representation (from enumeration representation clauses). + + if not Same_Representation (Target_Type, Operand_Type) then + + -- Convert: x(y) to x'val (ytyp'val (y)) + + Rewrite (N, + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Target_Type, Loc), + Attribute_Name => Name_Val, + Expressions => New_List ( + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Operand_Type, Loc), + Attribute_Name => Name_Pos, + Expressions => New_List (Operand))))); + + Analyze_And_Resolve (N, Target_Type); + end if; + + -- Case of conversions to floating-point + + elsif Is_Floating_Point_Type (Target_Type) then + Real_Range_Check; + end if; + + -- At this stage, either the conversion node has been transformed into + -- some other equivalent expression, or left as a conversion that can be + -- handled by Gigi, in the following cases: + + -- Conversions with no change of representation or type + + -- Numeric conversions involving integer, floating- and fixed-point + -- values. Fixed-point values are allowed only if Conversion_OK is + -- set, i.e. if the fixed-point values are to be treated as integers. + + -- No other conversions should be passed to Gigi + + -- Check: are these rules stated in sinfo??? if so, why restate here??? + + -- The only remaining step is to generate a range check if we still have + -- a type conversion at this stage and Do_Range_Check is set. For now we + -- do this only for conversions of discrete types and for float-to-float + -- conversions. + + if Nkind (N) = N_Type_Conversion then + + -- For now we only support floating-point cases where both source + -- and target are floating-point types. Conversions where the source + -- and target involve integer or fixed-point types are still TBD, + -- though not clear whether those can even happen at this point, due + -- to transformations above. ??? + + if Is_Floating_Point_Type (Etype (N)) + and then Is_Floating_Point_Type (Etype (Expression (N))) + then + if Do_Range_Check (Expression (N)) + and then Is_Floating_Point_Type (Target_Type) + then + Generate_Range_Check + (Expression (N), Target_Type, CE_Range_Check_Failed); + end if; + + -- Discrete-to-discrete conversions + + elsif Is_Discrete_Type (Etype (N)) then + declare + Expr : constant Node_Id := Expression (N); + Ftyp : Entity_Id; + Ityp : Entity_Id; + + begin + if Do_Range_Check (Expr) + and then Is_Discrete_Type (Etype (Expr)) + then + Set_Do_Range_Check (Expr, False); + + -- Before we do a range check, we have to deal with treating + -- a fixed-point operand as an integer. The way we do this + -- is simply to do an unchecked conversion to an appropriate + -- integer type large enough to hold the result. + + -- This code is not active yet, because we are only dealing + -- with discrete types so far ??? + + if Nkind (Expr) in N_Has_Treat_Fixed_As_Integer + and then Treat_Fixed_As_Integer (Expr) + then + Ftyp := Base_Type (Etype (Expr)); + + if Esize (Ftyp) >= Esize (Standard_Integer) then + Ityp := Standard_Long_Long_Integer; + else + Ityp := Standard_Integer; + end if; + + Rewrite (Expr, Unchecked_Convert_To (Ityp, Expr)); + end if; + + -- Reset overflow flag, since the range check will include + -- dealing with possible overflow, and generate the check. + -- If Address is either a source type or target type, + -- suppress range check to avoid typing anomalies when + -- it is a visible integer type. + + Set_Do_Overflow_Check (N, False); + + if not Is_Descendant_Of_Address (Etype (Expr)) + and then not Is_Descendant_Of_Address (Target_Type) + then + Generate_Range_Check + (Expr, Target_Type, CE_Range_Check_Failed); + end if; + end if; + end; + end if; + end if; + + -- Here at end of processing + + <<Done>> + -- Apply predicate check if required. Note that we can't just call + -- Apply_Predicate_Check here, because the type looks right after + -- the conversion and it would omit the check. The Comes_From_Source + -- guard is necessary to prevent infinite recursions when we generate + -- internal conversions for the purpose of checking predicates. + + if Present (Predicate_Function (Target_Type)) + and then not Predicates_Ignored (Target_Type) + and then Target_Type /= Operand_Type + and then Comes_From_Source (N) + then + declare + New_Expr : constant Node_Id := Duplicate_Subexpr (N); + + begin + -- Avoid infinite recursion on the subsequent expansion of + -- of the copy of the original type conversion. + + Set_Comes_From_Source (New_Expr, False); + Insert_Action (N, Make_Predicate_Check (Target_Type, New_Expr)); + end; + end if; + end Expand_N_Type_Conversion; + + ----------------------------------- + -- Expand_N_Unchecked_Expression -- + ----------------------------------- + + -- Remove the unchecked expression node from the tree. Its job was simply + -- to make sure that its constituent expression was handled with checks + -- off, and now that that is done, we can remove it from the tree, and + -- indeed must, since Gigi does not expect to see these nodes. + + procedure Expand_N_Unchecked_Expression (N : Node_Id) is + Exp : constant Node_Id := Expression (N); + begin + Set_Assignment_OK (Exp, Assignment_OK (N) or else Assignment_OK (Exp)); + Rewrite (N, Exp); + end Expand_N_Unchecked_Expression; + + ---------------------------------------- + -- Expand_N_Unchecked_Type_Conversion -- + ---------------------------------------- + + -- If this cannot be handled by Gigi and we haven't already made a + -- temporary for it, do it now. + + procedure Expand_N_Unchecked_Type_Conversion (N : Node_Id) is + Target_Type : constant Entity_Id := Etype (N); + Operand : constant Node_Id := Expression (N); + Operand_Type : constant Entity_Id := Etype (Operand); + + begin + -- Nothing at all to do if conversion is to the identical type so remove + -- the conversion completely, it is useless, except that it may carry + -- an Assignment_OK indication which must be propagated to the operand. + + if Operand_Type = Target_Type then + + -- Code duplicates Expand_N_Unchecked_Expression above, factor??? + + if Assignment_OK (N) then + Set_Assignment_OK (Operand); + end if; + + Rewrite (N, Relocate_Node (Operand)); + return; + end if; + + -- If we have a conversion of a compile time known value to a target + -- type and the value is in range of the target type, then we can simply + -- replace the construct by an integer literal of the correct type. We + -- only apply this to integer types being converted. Possibly it may + -- apply in other cases, but it is too much trouble to worry about. + + -- Note that we do not do this transformation if the Kill_Range_Check + -- flag is set, since then the value may be outside the expected range. + -- This happens in the Normalize_Scalars case. + + -- We also skip this if either the target or operand type is biased + -- because in this case, the unchecked conversion is supposed to + -- preserve the bit pattern, not the integer value. + + if Is_Integer_Type (Target_Type) + and then not Has_Biased_Representation (Target_Type) + and then Is_Integer_Type (Operand_Type) + and then not Has_Biased_Representation (Operand_Type) + and then Compile_Time_Known_Value (Operand) + and then not Kill_Range_Check (N) + then + declare + Val : constant Uint := Expr_Value (Operand); + + begin + if Compile_Time_Known_Value (Type_Low_Bound (Target_Type)) + and then + Compile_Time_Known_Value (Type_High_Bound (Target_Type)) + and then + Val >= Expr_Value (Type_Low_Bound (Target_Type)) + and then + Val <= Expr_Value (Type_High_Bound (Target_Type)) + then + Rewrite (N, Make_Integer_Literal (Sloc (N), Val)); + + -- If Address is the target type, just set the type to avoid a + -- spurious type error on the literal when Address is a visible + -- integer type. + + if Is_Descendant_Of_Address (Target_Type) then + Set_Etype (N, Target_Type); + else + Analyze_And_Resolve (N, Target_Type); + end if; + + return; + end if; + end; + end if; + + -- Nothing to do if conversion is safe + + if Safe_Unchecked_Type_Conversion (N) then + return; + end if; + + -- Otherwise force evaluation unless Assignment_OK flag is set (this + -- flag indicates ??? More comments needed here) + + if Assignment_OK (N) then + null; + else + Force_Evaluation (N); + end if; + end Expand_N_Unchecked_Type_Conversion; + + ---------------------------- + -- Expand_Record_Equality -- + ---------------------------- + + -- For non-variant records, Equality is expanded when needed into: + + -- and then Lhs.Discr1 = Rhs.Discr1 + -- and then ... + -- and then Lhs.Discrn = Rhs.Discrn + -- and then Lhs.Cmp1 = Rhs.Cmp1 + -- and then ... + -- and then Lhs.Cmpn = Rhs.Cmpn + + -- The expression is folded by the back end for adjacent fields. This + -- function is called for tagged record in only one occasion: for imple- + -- menting predefined primitive equality (see Predefined_Primitives_Bodies) + -- otherwise the primitive "=" is used directly. + + function Expand_Record_Equality + (Nod : Node_Id; + Typ : Entity_Id; + Lhs : Node_Id; + Rhs : Node_Id; + Bodies : List_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (Nod); + + Result : Node_Id; + C : Entity_Id; + + First_Time : Boolean := True; + + function Element_To_Compare (C : Entity_Id) return Entity_Id; + -- Return the next discriminant or component to compare, starting with + -- C, skipping inherited components. + + ------------------------ + -- Element_To_Compare -- + ------------------------ + + function Element_To_Compare (C : Entity_Id) return Entity_Id is + Comp : Entity_Id; + + begin + Comp := C; + loop + -- Exit loop when the next element to be compared is found, or + -- there is no more such element. + + exit when No (Comp); + + exit when Ekind_In (Comp, E_Discriminant, E_Component) + and then not ( + + -- Skip inherited components + + -- Note: for a tagged type, we always generate the "=" primitive + -- for the base type (not on the first subtype), so the test for + -- Comp /= Original_Record_Component (Comp) is True for + -- inherited components only. + + (Is_Tagged_Type (Typ) + and then Comp /= Original_Record_Component (Comp)) + + -- Skip _Tag + + or else Chars (Comp) = Name_uTag + + -- Skip interface elements (secondary tags???) + + or else Is_Interface (Etype (Comp))); + + Next_Entity (Comp); + end loop; + + return Comp; + end Element_To_Compare; + + -- Start of processing for Expand_Record_Equality + + begin + -- Generates the following code: (assuming that Typ has one Discr and + -- component C2 is also a record) + + -- True + -- and then Lhs.Discr1 = Rhs.Discr1 + -- and then Lhs.C1 = Rhs.C1 + -- and then Lhs.C2.C1=Rhs.C2.C1 and then ... Lhs.C2.Cn=Rhs.C2.Cn + -- and then ... + -- and then Lhs.Cmpn = Rhs.Cmpn + + Result := New_Occurrence_Of (Standard_True, Loc); + C := Element_To_Compare (First_Entity (Typ)); + while Present (C) loop + declare + New_Lhs : Node_Id; + New_Rhs : Node_Id; + Check : Node_Id; + + begin + if First_Time then + First_Time := False; + New_Lhs := Lhs; + New_Rhs := Rhs; + else + New_Lhs := New_Copy_Tree (Lhs); + New_Rhs := New_Copy_Tree (Rhs); + end if; + + Check := + Expand_Composite_Equality (Nod, Etype (C), + Lhs => + Make_Selected_Component (Loc, + Prefix => New_Lhs, + Selector_Name => New_Occurrence_Of (C, Loc)), + Rhs => + Make_Selected_Component (Loc, + Prefix => New_Rhs, + Selector_Name => New_Occurrence_Of (C, Loc)), + Bodies => Bodies); + + -- If some (sub)component is an unchecked_union, the whole + -- operation will raise program error. + + if Nkind (Check) = N_Raise_Program_Error then + Result := Check; + Set_Etype (Result, Standard_Boolean); + exit; + else + Result := + Make_And_Then (Loc, + Left_Opnd => Result, + Right_Opnd => Check); + end if; + end; + + C := Element_To_Compare (Next_Entity (C)); + end loop; + + return Result; + end Expand_Record_Equality; + + --------------------------- + -- Expand_Set_Membership -- + --------------------------- + + procedure Expand_Set_Membership (N : Node_Id) is + Lop : constant Node_Id := Left_Opnd (N); + Alt : Node_Id; + Res : Node_Id; + + function Make_Cond (Alt : Node_Id) return Node_Id; + -- If the alternative is a subtype mark, create a simple membership + -- test. Otherwise create an equality test for it. + + --------------- + -- Make_Cond -- + --------------- + + function Make_Cond (Alt : Node_Id) return Node_Id is + Cond : Node_Id; + L : constant Node_Id := New_Copy (Lop); + R : constant Node_Id := Relocate_Node (Alt); + + begin + if (Is_Entity_Name (Alt) and then Is_Type (Entity (Alt))) + or else Nkind (Alt) = N_Range + then + Cond := + Make_In (Sloc (Alt), + Left_Opnd => L, + Right_Opnd => R); + else + Cond := + Make_Op_Eq (Sloc (Alt), + Left_Opnd => L, + Right_Opnd => R); + end if; + + return Cond; + end Make_Cond; + + -- Start of processing for Expand_Set_Membership + + begin + Remove_Side_Effects (Lop); + + Alt := Last (Alternatives (N)); + Res := Make_Cond (Alt); + + Prev (Alt); + while Present (Alt) loop + Res := + Make_Or_Else (Sloc (Alt), + Left_Opnd => Make_Cond (Alt), + Right_Opnd => Res); + Prev (Alt); + end loop; + + Rewrite (N, Res); + Analyze_And_Resolve (N, Standard_Boolean); + end Expand_Set_Membership; + + ----------------------------------- + -- Expand_Short_Circuit_Operator -- + ----------------------------------- + + -- Deal with special expansion if actions are present for the right operand + -- and deal with optimizing case of arguments being True or False. We also + -- deal with the special case of non-standard boolean values. + + procedure Expand_Short_Circuit_Operator (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Left : constant Node_Id := Left_Opnd (N); + Right : constant Node_Id := Right_Opnd (N); + LocR : constant Source_Ptr := Sloc (Right); + Actlist : List_Id; + + Shortcut_Value : constant Boolean := Nkind (N) = N_Or_Else; + Shortcut_Ent : constant Entity_Id := Boolean_Literals (Shortcut_Value); + -- If Left = Shortcut_Value then Right need not be evaluated + + function Make_Test_Expr (Opnd : Node_Id) return Node_Id; + -- For Opnd a boolean expression, return a Boolean expression equivalent + -- to Opnd /= Shortcut_Value. + + -------------------- + -- Make_Test_Expr -- + -------------------- + + function Make_Test_Expr (Opnd : Node_Id) return Node_Id is + begin + if Shortcut_Value then + return Make_Op_Not (Sloc (Opnd), Opnd); + else + return Opnd; + end if; + end Make_Test_Expr; + + -- Local variables + + Op_Var : Entity_Id; + -- Entity for a temporary variable holding the value of the operator, + -- used for expansion in the case where actions are present. + + -- Start of processing for Expand_Short_Circuit_Operator + + begin + -- Deal with non-standard booleans + + if Is_Boolean_Type (Typ) then + Adjust_Condition (Left); + Adjust_Condition (Right); + Set_Etype (N, Standard_Boolean); + end if; + + -- Check for cases where left argument is known to be True or False + + if Compile_Time_Known_Value (Left) then + + -- Mark SCO for left condition as compile time known + + if Generate_SCO and then Comes_From_Source (Left) then + Set_SCO_Condition (Left, Expr_Value_E (Left) = Standard_True); + end if; + + -- Rewrite True AND THEN Right / False OR ELSE Right to Right. + -- Any actions associated with Right will be executed unconditionally + -- and can thus be inserted into the tree unconditionally. + + if Expr_Value_E (Left) /= Shortcut_Ent then + if Present (Actions (N)) then + Insert_Actions (N, Actions (N)); + end if; + + Rewrite (N, Right); + + -- Rewrite False AND THEN Right / True OR ELSE Right to Left. + -- In this case we can forget the actions associated with Right, + -- since they will never be executed. + + else + Kill_Dead_Code (Right); + Kill_Dead_Code (Actions (N)); + Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); + end if; + + Adjust_Result_Type (N, Typ); + return; + end if; + + -- If Actions are present for the right operand, we have to do some + -- special processing. We can't just let these actions filter back into + -- code preceding the short circuit (which is what would have happened + -- if we had not trapped them in the short-circuit form), since they + -- must only be executed if the right operand of the short circuit is + -- executed and not otherwise. + + if Present (Actions (N)) then + Actlist := Actions (N); + + -- The old approach is to expand: + + -- left AND THEN right + + -- into + + -- C : Boolean := False; + -- IF left THEN + -- Actions; + -- IF right THEN + -- C := True; + -- END IF; + -- END IF; + + -- and finally rewrite the operator into a reference to C. Similarly + -- for left OR ELSE right, with negated values. Note that this + -- rewrite causes some difficulties for coverage analysis because + -- of the introduction of the new variable C, which obscures the + -- structure of the test. + + -- We use this "old approach" if Minimize_Expression_With_Actions + -- is True. + + if Minimize_Expression_With_Actions then + Op_Var := Make_Temporary (Loc, 'C', Related_Node => N); + + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Op_Var, + Object_Definition => + New_Occurrence_Of (Standard_Boolean, Loc), + Expression => + New_Occurrence_Of (Shortcut_Ent, Loc))); + + Append_To (Actlist, + Make_Implicit_If_Statement (Right, + Condition => Make_Test_Expr (Right), + Then_Statements => New_List ( + Make_Assignment_Statement (LocR, + Name => New_Occurrence_Of (Op_Var, LocR), + Expression => + New_Occurrence_Of + (Boolean_Literals (not Shortcut_Value), LocR))))); + + Insert_Action (N, + Make_Implicit_If_Statement (Left, + Condition => Make_Test_Expr (Left), + Then_Statements => Actlist)); + + Rewrite (N, New_Occurrence_Of (Op_Var, Loc)); + Analyze_And_Resolve (N, Standard_Boolean); + + -- The new approach (the default) is to use an + -- Expression_With_Actions node for the right operand of the + -- short-circuit form. Note that this solves the traceability + -- problems for coverage analysis. + + else + Rewrite (Right, + Make_Expression_With_Actions (LocR, + Expression => Relocate_Node (Right), + Actions => Actlist)); + + Set_Actions (N, No_List); + Analyze_And_Resolve (Right, Standard_Boolean); + end if; + + Adjust_Result_Type (N, Typ); + return; + end if; + + -- No actions present, check for cases of right argument True/False + + if Compile_Time_Known_Value (Right) then + + -- Mark SCO for left condition as compile time known + + if Generate_SCO and then Comes_From_Source (Right) then + Set_SCO_Condition (Right, Expr_Value_E (Right) = Standard_True); + end if; + + -- Change (Left and then True), (Left or else False) to Left. Note + -- that we know there are no actions associated with the right + -- operand, since we just checked for this case above. + + if Expr_Value_E (Right) /= Shortcut_Ent then + Rewrite (N, Left); + + -- Change (Left and then False), (Left or else True) to Right, + -- making sure to preserve any side effects associated with the Left + -- operand. + + else + Remove_Side_Effects (Left); + Rewrite (N, New_Occurrence_Of (Shortcut_Ent, Loc)); + end if; + end if; + + Adjust_Result_Type (N, Typ); + end Expand_Short_Circuit_Operator; + + ------------------------------------- + -- Fixup_Universal_Fixed_Operation -- + ------------------------------------- + + procedure Fixup_Universal_Fixed_Operation (N : Node_Id) is + Conv : constant Node_Id := Parent (N); + + begin + -- We must have a type conversion immediately above us + + pragma Assert (Nkind (Conv) = N_Type_Conversion); + + -- Normally the type conversion gives our target type. The exception + -- occurs in the case of the Round attribute, where the conversion + -- will be to universal real, and our real type comes from the Round + -- attribute (as well as an indication that we must round the result) + + if Nkind (Parent (Conv)) = N_Attribute_Reference + and then Attribute_Name (Parent (Conv)) = Name_Round + then + Set_Etype (N, Etype (Parent (Conv))); + Set_Rounded_Result (N); + + -- Normal case where type comes from conversion above us + + else + Set_Etype (N, Etype (Conv)); + end if; + end Fixup_Universal_Fixed_Operation; + + --------------------------------- + -- Has_Inferable_Discriminants -- + --------------------------------- + + function Has_Inferable_Discriminants (N : Node_Id) return Boolean is + + function Prefix_Is_Formal_Parameter (N : Node_Id) return Boolean; + -- Determines whether the left-most prefix of a selected component is a + -- formal parameter in a subprogram. Assumes N is a selected component. + + -------------------------------- + -- Prefix_Is_Formal_Parameter -- + -------------------------------- + + function Prefix_Is_Formal_Parameter (N : Node_Id) return Boolean is + Sel_Comp : Node_Id; + + begin + -- Move to the left-most prefix by climbing up the tree + + Sel_Comp := N; + while Present (Parent (Sel_Comp)) + and then Nkind (Parent (Sel_Comp)) = N_Selected_Component + loop + Sel_Comp := Parent (Sel_Comp); + end loop; + + return Ekind (Entity (Prefix (Sel_Comp))) in Formal_Kind; + end Prefix_Is_Formal_Parameter; + + -- Start of processing for Has_Inferable_Discriminants + + begin + -- For selected components, the subtype of the selector must be a + -- constrained Unchecked_Union. If the component is subject to a + -- per-object constraint, then the enclosing object must have inferable + -- discriminants. + + if Nkind (N) = N_Selected_Component then + if Has_Per_Object_Constraint (Entity (Selector_Name (N))) then + + -- A small hack. If we have a per-object constrained selected + -- component of a formal parameter, return True since we do not + -- know the actual parameter association yet. + + if Prefix_Is_Formal_Parameter (N) then + return True; + + -- Otherwise, check the enclosing object and the selector + + else + return Has_Inferable_Discriminants (Prefix (N)) + and then Has_Inferable_Discriminants (Selector_Name (N)); + end if; + + -- The call to Has_Inferable_Discriminants will determine whether + -- the selector has a constrained Unchecked_Union nominal type. + + else + return Has_Inferable_Discriminants (Selector_Name (N)); + end if; + + -- A qualified expression has inferable discriminants if its subtype + -- mark is a constrained Unchecked_Union subtype. + + elsif Nkind (N) = N_Qualified_Expression then + return Is_Unchecked_Union (Etype (Subtype_Mark (N))) + and then Is_Constrained (Etype (Subtype_Mark (N))); + + -- For all other names, it is sufficient to have a constrained + -- Unchecked_Union nominal subtype. + + else + return Is_Unchecked_Union (Base_Type (Etype (N))) + and then Is_Constrained (Etype (N)); + end if; + end Has_Inferable_Discriminants; + + ------------------------------- + -- Insert_Dereference_Action -- + ------------------------------- + + procedure Insert_Dereference_Action (N : Node_Id) is + function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean; + -- Return true if type of P is derived from Checked_Pool; + + ----------------------------- + -- Is_Checked_Storage_Pool -- + ----------------------------- + + function Is_Checked_Storage_Pool (P : Entity_Id) return Boolean is + T : Entity_Id; + + begin + if No (P) then + return False; + end if; + + T := Etype (P); + while T /= Etype (T) loop + if Is_RTE (T, RE_Checked_Pool) then + return True; + else + T := Etype (T); + end if; + end loop; + + return False; + end Is_Checked_Storage_Pool; + + -- Local variables + + Context : constant Node_Id := Parent (N); + Ptr_Typ : constant Entity_Id := Etype (N); + Desig_Typ : constant Entity_Id := + Available_View (Designated_Type (Ptr_Typ)); + Loc : constant Source_Ptr := Sloc (N); + Pool : constant Entity_Id := Associated_Storage_Pool (Ptr_Typ); + + Addr : Entity_Id; + Alig : Entity_Id; + Deref : Node_Id; + Size : Entity_Id; + Size_Bits : Node_Id; + Stmt : Node_Id; + + -- Start of processing for Insert_Dereference_Action + + begin + pragma Assert (Nkind (Context) = N_Explicit_Dereference); + + -- Do not re-expand a dereference which has already been processed by + -- this routine. + + if Has_Dereference_Action (Context) then + return; + + -- Do not perform this type of expansion for internally-generated + -- dereferences. + + elsif not Comes_From_Source (Original_Node (Context)) then + return; + + -- A dereference action is only applicable to objects which have been + -- allocated on a checked pool. + + elsif not Is_Checked_Storage_Pool (Pool) then + return; + end if; + + -- Extract the address of the dereferenced object. Generate: + + -- Addr : System.Address := <N>'Pool_Address; + + Addr := Make_Temporary (Loc, 'P'); + + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Addr, + Object_Definition => + New_Occurrence_Of (RTE (RE_Address), Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => Duplicate_Subexpr_Move_Checks (N), + Attribute_Name => Name_Pool_Address))); + + -- Calculate the size of the dereferenced object. Generate: + + -- Size : Storage_Count := <N>.all'Size / Storage_Unit; + + Deref := + Make_Explicit_Dereference (Loc, + Prefix => Duplicate_Subexpr_Move_Checks (N)); + Set_Has_Dereference_Action (Deref); + + Size_Bits := + Make_Attribute_Reference (Loc, + Prefix => Deref, + Attribute_Name => Name_Size); + + -- Special case of an unconstrained array: need to add descriptor size + + if Is_Array_Type (Desig_Typ) + and then not Is_Constrained (First_Subtype (Desig_Typ)) + then + Size_Bits := + Make_Op_Add (Loc, + Left_Opnd => + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (First_Subtype (Desig_Typ), Loc), + Attribute_Name => Name_Descriptor_Size), + Right_Opnd => Size_Bits); + end if; + + Size := Make_Temporary (Loc, 'S'); + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Size, + Object_Definition => + New_Occurrence_Of (RTE (RE_Storage_Count), Loc), + Expression => + Make_Op_Divide (Loc, + Left_Opnd => Size_Bits, + Right_Opnd => Make_Integer_Literal (Loc, System_Storage_Unit)))); + + -- Calculate the alignment of the dereferenced object. Generate: + -- Alig : constant Storage_Count := <N>.all'Alignment; + + Deref := + Make_Explicit_Dereference (Loc, + Prefix => Duplicate_Subexpr_Move_Checks (N)); + Set_Has_Dereference_Action (Deref); + + Alig := Make_Temporary (Loc, 'A'); + Insert_Action (N, + Make_Object_Declaration (Loc, + Defining_Identifier => Alig, + Object_Definition => + New_Occurrence_Of (RTE (RE_Storage_Count), Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => Deref, + Attribute_Name => Name_Alignment))); + + -- A dereference of a controlled object requires special processing. The + -- finalization machinery requests additional space from the underlying + -- pool to allocate and hide two pointers. As a result, a checked pool + -- may mark the wrong memory as valid. Since checked pools do not have + -- knowledge of hidden pointers, we have to bring the two pointers back + -- in view in order to restore the original state of the object. + + -- The address manipulation is not performed for access types that are + -- subject to pragma No_Heap_Finalization because the two pointers do + -- not exist in the first place. + + if No_Heap_Finalization (Ptr_Typ) then + null; + + elsif Needs_Finalization (Desig_Typ) then + + -- Adjust the address and size of the dereferenced object. Generate: + -- Adjust_Controlled_Dereference (Addr, Size, Alig); + + Stmt := + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (RTE (RE_Adjust_Controlled_Dereference), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (Addr, Loc), + New_Occurrence_Of (Size, Loc), + New_Occurrence_Of (Alig, Loc))); + + -- Class-wide types complicate things because we cannot determine + -- statically whether the actual object is truly controlled. We must + -- generate a runtime check to detect this property. Generate: + -- + -- if Needs_Finalization (<N>.all'Tag) then + -- <Stmt>; + -- end if; + + if Is_Class_Wide_Type (Desig_Typ) then + Deref := + Make_Explicit_Dereference (Loc, + Prefix => Duplicate_Subexpr_Move_Checks (N)); + Set_Has_Dereference_Action (Deref); + + Stmt := + Make_Implicit_If_Statement (N, + Condition => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Needs_Finalization), Loc), + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => Deref, + Attribute_Name => Name_Tag))), + Then_Statements => New_List (Stmt)); + end if; + + Insert_Action (N, Stmt); + end if; + + -- Generate: + -- Dereference (Pool, Addr, Size, Alig); + + Insert_Action (N, + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of + (Find_Prim_Op (Etype (Pool), Name_Dereference), Loc), + Parameter_Associations => New_List ( + New_Occurrence_Of (Pool, Loc), + New_Occurrence_Of (Addr, Loc), + New_Occurrence_Of (Size, Loc), + New_Occurrence_Of (Alig, Loc)))); + + -- Mark the explicit dereference as processed to avoid potential + -- infinite expansion. + + Set_Has_Dereference_Action (Context); + + exception + when RE_Not_Available => + return; + end Insert_Dereference_Action; + + -------------------------------- + -- Integer_Promotion_Possible -- + -------------------------------- + + function Integer_Promotion_Possible (N : Node_Id) return Boolean is + Operand : constant Node_Id := Expression (N); + Operand_Type : constant Entity_Id := Etype (Operand); + Root_Operand_Type : constant Entity_Id := Root_Type (Operand_Type); + + begin + pragma Assert (Nkind (N) = N_Type_Conversion); + + return + + -- We only do the transformation for source constructs. We assume + -- that the expander knows what it is doing when it generates code. + + Comes_From_Source (N) + + -- If the operand type is Short_Integer or Short_Short_Integer, + -- then we will promote to Integer, which is available on all + -- targets, and is sufficient to ensure no intermediate overflow. + -- Furthermore it is likely to be as efficient or more efficient + -- than using the smaller type for the computation so we do this + -- unconditionally. + + and then + (Root_Operand_Type = Base_Type (Standard_Short_Integer) + or else + Root_Operand_Type = Base_Type (Standard_Short_Short_Integer)) + + -- Test for interesting operation, which includes addition, + -- division, exponentiation, multiplication, subtraction, absolute + -- value and unary negation. Unary "+" is omitted since it is a + -- no-op and thus can't overflow. + + and then Nkind_In (Operand, N_Op_Abs, + N_Op_Add, + N_Op_Divide, + N_Op_Expon, + N_Op_Minus, + N_Op_Multiply, + N_Op_Subtract); + end Integer_Promotion_Possible; + + ------------------------------ + -- Make_Array_Comparison_Op -- + ------------------------------ + + -- This is a hand-coded expansion of the following generic function: + + -- generic + -- type elem is (<>); + -- type index is (<>); + -- type a is array (index range <>) of elem; + + -- function Gnnn (X : a; Y: a) return boolean is + -- J : index := Y'first; + + -- begin + -- if X'length = 0 then + -- return false; + + -- elsif Y'length = 0 then + -- return true; + + -- else + -- for I in X'range loop + -- if X (I) = Y (J) then + -- if J = Y'last then + -- exit; + -- else + -- J := index'succ (J); + -- end if; + + -- else + -- return X (I) > Y (J); + -- end if; + -- end loop; + + -- return X'length > Y'length; + -- end if; + -- end Gnnn; + + -- Note that since we are essentially doing this expansion by hand, we + -- do not need to generate an actual or formal generic part, just the + -- instantiated function itself. + + -- Perhaps we could have the actual generic available in the run-time, + -- obtained by rtsfind, and actually expand a real instantiation ??? + + function Make_Array_Comparison_Op + (Typ : Entity_Id; + Nod : Node_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (Nod); + + X : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uX); + Y : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uY); + I : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uI); + J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); + + Index : constant Entity_Id := Base_Type (Etype (First_Index (Typ))); + + Loop_Statement : Node_Id; + Loop_Body : Node_Id; + If_Stat : Node_Id; + Inner_If : Node_Id; + Final_Expr : Node_Id; + Func_Body : Node_Id; + Func_Name : Entity_Id; + Formals : List_Id; + Length1 : Node_Id; + Length2 : Node_Id; + + begin + -- if J = Y'last then + -- exit; + -- else + -- J := index'succ (J); + -- end if; + + Inner_If := + Make_Implicit_If_Statement (Nod, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (J, Loc), + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Attribute_Name => Name_Last)), + + Then_Statements => New_List ( + Make_Exit_Statement (Loc)), + + Else_Statements => + New_List ( + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (J, Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Index, Loc), + Attribute_Name => Name_Succ, + Expressions => New_List (New_Occurrence_Of (J, Loc)))))); + + -- if X (I) = Y (J) then + -- if ... end if; + -- else + -- return X (I) > Y (J); + -- end if; + + Loop_Body := + Make_Implicit_If_Statement (Nod, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (X, Loc), + Expressions => New_List (New_Occurrence_Of (I, Loc))), + + Right_Opnd => + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc)))), + + Then_Statements => New_List (Inner_If), + + Else_Statements => New_List ( + Make_Simple_Return_Statement (Loc, + Expression => + Make_Op_Gt (Loc, + Left_Opnd => + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (X, Loc), + Expressions => New_List (New_Occurrence_Of (I, Loc))), + + Right_Opnd => + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Expressions => New_List ( + New_Occurrence_Of (J, Loc))))))); + + -- for I in X'range loop + -- if ... end if; + -- end loop; + + Loop_Statement := + Make_Implicit_Loop_Statement (Nod, + Identifier => Empty, + + Iteration_Scheme => + Make_Iteration_Scheme (Loc, + Loop_Parameter_Specification => + Make_Loop_Parameter_Specification (Loc, + Defining_Identifier => I, + Discrete_Subtype_Definition => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (X, Loc), + Attribute_Name => Name_Range))), + + Statements => New_List (Loop_Body)); + + -- if X'length = 0 then + -- return false; + -- elsif Y'length = 0 then + -- return true; + -- else + -- for ... loop ... end loop; + -- return X'length > Y'length; + -- end if; + + Length1 := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (X, Loc), + Attribute_Name => Name_Length); + + Length2 := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Attribute_Name => Name_Length); + + Final_Expr := + Make_Op_Gt (Loc, + Left_Opnd => Length1, + Right_Opnd => Length2); + + If_Stat := + Make_Implicit_If_Statement (Nod, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (X, Loc), + Attribute_Name => Name_Length), + Right_Opnd => + Make_Integer_Literal (Loc, 0)), + + Then_Statements => + New_List ( + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Standard_False, Loc))), + + Elsif_Parts => New_List ( + Make_Elsif_Part (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Attribute_Name => Name_Length), + Right_Opnd => + Make_Integer_Literal (Loc, 0)), + + Then_Statements => + New_List ( + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Standard_True, Loc))))), + + Else_Statements => New_List ( + Loop_Statement, + Make_Simple_Return_Statement (Loc, + Expression => Final_Expr))); + + -- (X : a; Y: a) + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => X, + Parameter_Type => New_Occurrence_Of (Typ, Loc)), + + Make_Parameter_Specification (Loc, + Defining_Identifier => Y, + Parameter_Type => New_Occurrence_Of (Typ, Loc))); + + -- function Gnnn (...) return boolean is + -- J : index := Y'first; + -- begin + -- if ... end if; + -- end Gnnn; + + Func_Name := Make_Temporary (Loc, 'G'); + + Func_Body := + Make_Subprogram_Body (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Func_Name, + Parameter_Specifications => Formals, + Result_Definition => New_Occurrence_Of (Standard_Boolean, Loc)), + + Declarations => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => J, + Object_Definition => New_Occurrence_Of (Index, Loc), + Expression => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Y, Loc), + Attribute_Name => Name_First))), + + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (If_Stat))); + + return Func_Body; + end Make_Array_Comparison_Op; + + --------------------------- + -- Make_Boolean_Array_Op -- + --------------------------- + + -- For logical operations on boolean arrays, expand in line the following, + -- replacing 'and' with 'or' or 'xor' where needed: + + -- function Annn (A : typ; B: typ) return typ is + -- C : typ; + -- begin + -- for J in A'range loop + -- C (J) := A (J) op B (J); + -- end loop; + -- return C; + -- end Annn; + + -- Here typ is the boolean array type + + function Make_Boolean_Array_Op + (Typ : Entity_Id; + N : Node_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (N); + + A : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uA); + B : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uB); + C : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uC); + J : constant Entity_Id := Make_Defining_Identifier (Loc, Name_uJ); + + A_J : Node_Id; + B_J : Node_Id; + C_J : Node_Id; + Op : Node_Id; + + Formals : List_Id; + Func_Name : Entity_Id; + Func_Body : Node_Id; + Loop_Statement : Node_Id; + + begin + A_J := + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (A, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc))); + + B_J := + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (B, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc))); + + C_J := + Make_Indexed_Component (Loc, + Prefix => New_Occurrence_Of (C, Loc), + Expressions => New_List (New_Occurrence_Of (J, Loc))); + + if Nkind (N) = N_Op_And then + Op := + Make_Op_And (Loc, + Left_Opnd => A_J, + Right_Opnd => B_J); + + elsif Nkind (N) = N_Op_Or then + Op := + Make_Op_Or (Loc, + Left_Opnd => A_J, + Right_Opnd => B_J); + + else + Op := + Make_Op_Xor (Loc, + Left_Opnd => A_J, + Right_Opnd => B_J); + end if; + + Loop_Statement := + Make_Implicit_Loop_Statement (N, + Identifier => Empty, + + Iteration_Scheme => + Make_Iteration_Scheme (Loc, + Loop_Parameter_Specification => + Make_Loop_Parameter_Specification (Loc, + Defining_Identifier => J, + Discrete_Subtype_Definition => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (A, Loc), + Attribute_Name => Name_Range))), + + Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => C_J, + Expression => Op))); + + Formals := New_List ( + Make_Parameter_Specification (Loc, + Defining_Identifier => A, + Parameter_Type => New_Occurrence_Of (Typ, Loc)), + + Make_Parameter_Specification (Loc, + Defining_Identifier => B, + Parameter_Type => New_Occurrence_Of (Typ, Loc))); + + Func_Name := Make_Temporary (Loc, 'A'); + Set_Is_Inlined (Func_Name); + + Func_Body := + Make_Subprogram_Body (Loc, + Specification => + Make_Function_Specification (Loc, + Defining_Unit_Name => Func_Name, + Parameter_Specifications => Formals, + Result_Definition => New_Occurrence_Of (Typ, Loc)), + + Declarations => New_List ( + Make_Object_Declaration (Loc, + Defining_Identifier => C, + Object_Definition => New_Occurrence_Of (Typ, Loc))), + + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Loop_Statement, + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (C, Loc))))); + + return Func_Body; + end Make_Boolean_Array_Op; + + ----------------------------------------- + -- Minimized_Eliminated_Overflow_Check -- + ----------------------------------------- + + function Minimized_Eliminated_Overflow_Check (N : Node_Id) return Boolean is + begin + return + Is_Signed_Integer_Type (Etype (N)) + and then Overflow_Check_Mode in Minimized_Or_Eliminated; + end Minimized_Eliminated_Overflow_Check; + + -------------------------------- + -- Optimize_Length_Comparison -- + -------------------------------- + + procedure Optimize_Length_Comparison (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Typ : constant Entity_Id := Etype (N); + Result : Node_Id; + + Left : Node_Id; + Right : Node_Id; + -- First and Last attribute reference nodes, which end up as left and + -- right operands of the optimized result. + + Is_Zero : Boolean; + -- True for comparison operand of zero + + Comp : Node_Id; + -- Comparison operand, set only if Is_Zero is false + + Ent : Entity_Id; + -- Entity whose length is being compared + + Index : Node_Id; + -- Integer_Literal node for length attribute expression, or Empty + -- if there is no such expression present. + + Ityp : Entity_Id; + -- Type of array index to which 'Length is applied + + Op : Node_Kind := Nkind (N); + -- Kind of comparison operator, gets flipped if operands backwards + + function Is_Optimizable (N : Node_Id) return Boolean; + -- Tests N to see if it is an optimizable comparison value (defined as + -- constant zero or one, or something else where the value is known to + -- be positive and in the range of 32-bits, and where the corresponding + -- Length value is also known to be 32-bits. If result is true, sets + -- Is_Zero, Ityp, and Comp accordingly. + + function Is_Entity_Length (N : Node_Id) return Boolean; + -- Tests if N is a length attribute applied to a simple entity. If so, + -- returns True, and sets Ent to the entity, and Index to the integer + -- literal provided as an attribute expression, or to Empty if none. + -- Also returns True if the expression is a generated type conversion + -- whose expression is of the desired form. This latter case arises + -- when Apply_Universal_Integer_Attribute_Check installs a conversion + -- to check for being in range, which is not needed in this context. + -- Returns False if neither condition holds. + + function Prepare_64 (N : Node_Id) return Node_Id; + -- Given a discrete expression, returns a Long_Long_Integer typed + -- expression representing the underlying value of the expression. + -- This is done with an unchecked conversion to the result type. We + -- use unchecked conversion to handle the enumeration type case. + + ---------------------- + -- Is_Entity_Length -- + ---------------------- + + function Is_Entity_Length (N : Node_Id) return Boolean is + begin + if Nkind (N) = N_Attribute_Reference + and then Attribute_Name (N) = Name_Length + and then Is_Entity_Name (Prefix (N)) + then + Ent := Entity (Prefix (N)); + + if Present (Expressions (N)) then + Index := First (Expressions (N)); + else + Index := Empty; + end if; + + return True; + + elsif Nkind (N) = N_Type_Conversion + and then not Comes_From_Source (N) + then + return Is_Entity_Length (Expression (N)); + + else + return False; + end if; + end Is_Entity_Length; + + -------------------- + -- Is_Optimizable -- + -------------------- + + function Is_Optimizable (N : Node_Id) return Boolean is + Val : Uint; + OK : Boolean; + Lo : Uint; + Hi : Uint; + Indx : Node_Id; + + begin + if Compile_Time_Known_Value (N) then + Val := Expr_Value (N); + + if Val = Uint_0 then + Is_Zero := True; + Comp := Empty; + return True; + + elsif Val = Uint_1 then + Is_Zero := False; + Comp := Empty; + return True; + end if; + end if; + + -- Here we have to make sure of being within 32-bits + + Determine_Range (N, OK, Lo, Hi, Assume_Valid => True); + + if not OK + or else Lo < Uint_1 + or else Hi > UI_From_Int (Int'Last) + then + return False; + end if; + + -- Comparison value was within range, so now we must check the index + -- value to make sure it is also within 32-bits. + + Indx := First_Index (Etype (Ent)); + + if Present (Index) then + for J in 2 .. UI_To_Int (Intval (Index)) loop + Next_Index (Indx); + end loop; + end if; + + Ityp := Etype (Indx); + + if Esize (Ityp) > 32 then + return False; + end if; + + Is_Zero := False; + Comp := N; + return True; + end Is_Optimizable; + + ---------------- + -- Prepare_64 -- + ---------------- + + function Prepare_64 (N : Node_Id) return Node_Id is + begin + return Unchecked_Convert_To (Standard_Long_Long_Integer, N); + end Prepare_64; + + -- Start of processing for Optimize_Length_Comparison + + begin + -- Nothing to do if not a comparison + + if Op not in N_Op_Compare then + return; + end if; + + -- Nothing to do if special -gnatd.P debug flag set. + + if Debug_Flag_Dot_PP then + return; + end if; + + -- Ent'Length op 0/1 + + if Is_Entity_Length (Left_Opnd (N)) + and then Is_Optimizable (Right_Opnd (N)) + then + null; + + -- 0/1 op Ent'Length + + elsif Is_Entity_Length (Right_Opnd (N)) + and then Is_Optimizable (Left_Opnd (N)) + then + -- Flip comparison to opposite sense + + case Op is + when N_Op_Lt => Op := N_Op_Gt; + when N_Op_Le => Op := N_Op_Ge; + when N_Op_Gt => Op := N_Op_Lt; + when N_Op_Ge => Op := N_Op_Le; + when others => null; + end case; + + -- Else optimization not possible + + else + return; + end if; + + -- Fall through if we will do the optimization + + -- Cases to handle: + + -- X'Length = 0 => X'First > X'Last + -- X'Length = 1 => X'First = X'Last + -- X'Length = n => X'First + (n - 1) = X'Last + + -- X'Length /= 0 => X'First <= X'Last + -- X'Length /= 1 => X'First /= X'Last + -- X'Length /= n => X'First + (n - 1) /= X'Last + + -- X'Length >= 0 => always true, warn + -- X'Length >= 1 => X'First <= X'Last + -- X'Length >= n => X'First + (n - 1) <= X'Last + + -- X'Length > 0 => X'First <= X'Last + -- X'Length > 1 => X'First < X'Last + -- X'Length > n => X'First + (n - 1) < X'Last + + -- X'Length <= 0 => X'First > X'Last (warn, could be =) + -- X'Length <= 1 => X'First >= X'Last + -- X'Length <= n => X'First + (n - 1) >= X'Last + + -- X'Length < 0 => always false (warn) + -- X'Length < 1 => X'First > X'Last + -- X'Length < n => X'First + (n - 1) > X'Last + + -- Note: for the cases of n (not constant 0,1), we require that the + -- corresponding index type be integer or shorter (i.e. not 64-bit), + -- and the same for the comparison value. Then we do the comparison + -- using 64-bit arithmetic (actually long long integer), so that we + -- cannot have overflow intefering with the result. + + -- First deal with warning cases + + if Is_Zero then + case Op is + + -- X'Length >= 0 + + when N_Op_Ge => + Rewrite (N, + Convert_To (Typ, New_Occurrence_Of (Standard_True, Loc))); + Analyze_And_Resolve (N, Typ); + Warn_On_Known_Condition (N); + return; + + -- X'Length < 0 + + when N_Op_Lt => + Rewrite (N, + Convert_To (Typ, New_Occurrence_Of (Standard_False, Loc))); + Analyze_And_Resolve (N, Typ); + Warn_On_Known_Condition (N); + return; + + when N_Op_Le => + if Constant_Condition_Warnings + and then Comes_From_Source (Original_Node (N)) + then + Error_Msg_N ("could replace by ""'=""?c?", N); + end if; + + Op := N_Op_Eq; + + when others => + null; + end case; + end if; + + -- Build the First reference we will use + + Left := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Ent, Loc), + Attribute_Name => Name_First); + + if Present (Index) then + Set_Expressions (Left, New_List (New_Copy (Index))); + end if; + + -- If general value case, then do the addition of (n - 1), and + -- also add the needed conversions to type Long_Long_Integer. + + if Present (Comp) then + Left := + Make_Op_Add (Loc, + Left_Opnd => Prepare_64 (Left), + Right_Opnd => + Make_Op_Subtract (Loc, + Left_Opnd => Prepare_64 (Comp), + Right_Opnd => Make_Integer_Literal (Loc, 1))); + end if; + + -- Build the Last reference we will use + + Right := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Ent, Loc), + Attribute_Name => Name_Last); + + if Present (Index) then + Set_Expressions (Right, New_List (New_Copy (Index))); + end if; + + -- If general operand, convert Last reference to Long_Long_Integer + + if Present (Comp) then + Right := Prepare_64 (Right); + end if; + + -- Check for cases to optimize + + -- X'Length = 0 => X'First > X'Last + -- X'Length < 1 => X'First > X'Last + -- X'Length < n => X'First + (n - 1) > X'Last + + if (Is_Zero and then Op = N_Op_Eq) + or else (not Is_Zero and then Op = N_Op_Lt) + then + Result := + Make_Op_Gt (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length = 1 => X'First = X'Last + -- X'Length = n => X'First + (n - 1) = X'Last + + elsif not Is_Zero and then Op = N_Op_Eq then + Result := + Make_Op_Eq (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length /= 0 => X'First <= X'Last + -- X'Length > 0 => X'First <= X'Last + + elsif Is_Zero and (Op = N_Op_Ne or else Op = N_Op_Gt) then + Result := + Make_Op_Le (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length /= 1 => X'First /= X'Last + -- X'Length /= n => X'First + (n - 1) /= X'Last + + elsif not Is_Zero and then Op = N_Op_Ne then + Result := + Make_Op_Ne (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length >= 1 => X'First <= X'Last + -- X'Length >= n => X'First + (n - 1) <= X'Last + + elsif not Is_Zero and then Op = N_Op_Ge then + Result := + Make_Op_Le (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length > 1 => X'First < X'Last + -- X'Length > n => X'First + (n = 1) < X'Last + + elsif not Is_Zero and then Op = N_Op_Gt then + Result := + Make_Op_Lt (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- X'Length <= 1 => X'First >= X'Last + -- X'Length <= n => X'First + (n - 1) >= X'Last + + elsif not Is_Zero and then Op = N_Op_Le then + Result := + Make_Op_Ge (Loc, + Left_Opnd => Left, + Right_Opnd => Right); + + -- Should not happen at this stage + + else + raise Program_Error; + end if; + + -- Rewrite and finish up + + Rewrite (N, Result); + Analyze_And_Resolve (N, Typ); + return; + end Optimize_Length_Comparison; + + -------------------------------- + -- Process_If_Case_Statements -- + -------------------------------- + + procedure Process_If_Case_Statements (N : Node_Id; Stmts : List_Id) is + Decl : Node_Id; + + begin + Decl := First (Stmts); + while Present (Decl) loop + if Nkind (Decl) = N_Object_Declaration + and then Is_Finalizable_Transient (Decl, N) + then + Process_Transient_In_Expression (Decl, N, Stmts); + end if; + + Next (Decl); + end loop; + end Process_If_Case_Statements; + + ------------------------------------- + -- Process_Transient_In_Expression -- + ------------------------------------- + + procedure Process_Transient_In_Expression + (Obj_Decl : Node_Id; + Expr : Node_Id; + Stmts : List_Id) + is + Loc : constant Source_Ptr := Sloc (Obj_Decl); + Obj_Id : constant Entity_Id := Defining_Identifier (Obj_Decl); + + Hook_Context : constant Node_Id := Find_Hook_Context (Expr); + -- The node on which to insert the hook as an action. This is usually + -- the innermost enclosing non-transient construct. + + Fin_Call : Node_Id; + Hook_Assign : Node_Id; + Hook_Clear : Node_Id; + Hook_Decl : Node_Id; + Hook_Insert : Node_Id; + Ptr_Decl : Node_Id; + + Fin_Context : Node_Id; + -- The node after which to insert the finalization actions of the + -- transient object. + + begin + pragma Assert (Nkind_In (Expr, N_Case_Expression, + N_Expression_With_Actions, + N_If_Expression)); + + -- When the context is a Boolean evaluation, all three nodes capture the + -- result of their computation in a local temporary: + + -- do + -- Trans_Id : Ctrl_Typ := ...; + -- Result : constant Boolean := ... Trans_Id ...; + -- <finalize Trans_Id> + -- in Result end; + + -- As a result, the finalization of any transient objects can safely + -- take place after the result capture. + + -- ??? could this be extended to elementary types? + + if Is_Boolean_Type (Etype (Expr)) then + Fin_Context := Last (Stmts); + + -- Otherwise the immediate context may not be safe enough to carry + -- out transient object finalization due to aliasing and nesting of + -- constructs. Insert calls to [Deep_]Finalize after the innermost + -- enclosing non-transient construct. + + else + Fin_Context := Hook_Context; + end if; + + -- Mark the transient object as successfully processed to avoid double + -- finalization. + + Set_Is_Finalized_Transient (Obj_Id); + + -- Construct all the pieces necessary to hook and finalize a transient + -- object. + + Build_Transient_Object_Statements + (Obj_Decl => Obj_Decl, + Fin_Call => Fin_Call, + Hook_Assign => Hook_Assign, + Hook_Clear => Hook_Clear, + Hook_Decl => Hook_Decl, + Ptr_Decl => Ptr_Decl, + Finalize_Obj => False); + + -- Add the access type which provides a reference to the transient + -- object. Generate: + + -- type Ptr_Typ is access all Desig_Typ; + + Insert_Action (Hook_Context, Ptr_Decl); + + -- Add the temporary which acts as a hook to the transient object. + -- Generate: + + -- Hook : Ptr_Id := null; + + Insert_Action (Hook_Context, Hook_Decl); + + -- When the transient object is initialized by an aggregate, the hook + -- must capture the object after the last aggregate assignment takes + -- place. Only then is the object considered initialized. Generate: + + -- Hook := Ptr_Typ (Obj_Id); + -- <or> + -- Hook := Obj_Id'Unrestricted_Access; + + if Ekind_In (Obj_Id, E_Constant, E_Variable) + and then Present (Last_Aggregate_Assignment (Obj_Id)) + then + Hook_Insert := Last_Aggregate_Assignment (Obj_Id); + + -- Otherwise the hook seizes the related object immediately + + else + Hook_Insert := Obj_Decl; + end if; + + Insert_After_And_Analyze (Hook_Insert, Hook_Assign); + + -- When the node is part of a return statement, there is no need to + -- insert a finalization call, as the general finalization mechanism + -- (see Build_Finalizer) would take care of the transient object on + -- subprogram exit. Note that it would also be impossible to insert the + -- finalization code after the return statement as this will render it + -- unreachable. + + if Nkind (Fin_Context) = N_Simple_Return_Statement then + null; + + -- Finalize the hook after the context has been evaluated. Generate: + + -- if Hook /= null then + -- [Deep_]Finalize (Hook.all); + -- Hook := null; + -- end if; + + else + Insert_Action_After (Fin_Context, + Make_Implicit_If_Statement (Obj_Decl, + Condition => + Make_Op_Ne (Loc, + Left_Opnd => + New_Occurrence_Of (Defining_Entity (Hook_Decl), Loc), + Right_Opnd => Make_Null (Loc)), + + Then_Statements => New_List ( + Fin_Call, + Hook_Clear))); + end if; + end Process_Transient_In_Expression; + + ------------------------ + -- Rewrite_Comparison -- + ------------------------ + + procedure Rewrite_Comparison (N : Node_Id) is + Typ : constant Entity_Id := Etype (N); + + False_Result : Boolean; + True_Result : Boolean; + + begin + if Nkind (N) = N_Type_Conversion then + Rewrite_Comparison (Expression (N)); + return; + + elsif Nkind (N) not in N_Op_Compare then + return; + end if; + + -- Determine the potential outcome of the comparison assuming that the + -- operands are valid and emit a warning when the comparison evaluates + -- to True or False only in the presence of invalid values. + + Warn_On_Constant_Valid_Condition (N); + + -- Determine the potential outcome of the comparison assuming that the + -- operands are not valid. + + Test_Comparison + (Op => N, + Assume_Valid => False, + True_Result => True_Result, + False_Result => False_Result); + + -- The outcome is a decisive False or True, rewrite the operator + + if False_Result or True_Result then + Rewrite (N, + Convert_To (Typ, + New_Occurrence_Of (Boolean_Literals (True_Result), Sloc (N)))); + + Analyze_And_Resolve (N, Typ); + Warn_On_Known_Condition (N); + end if; + end Rewrite_Comparison; + + ---------------------------- + -- Safe_In_Place_Array_Op -- + ---------------------------- + + function Safe_In_Place_Array_Op + (Lhs : Node_Id; + Op1 : Node_Id; + Op2 : Node_Id) return Boolean + is + Target : Entity_Id; + + function Is_Safe_Operand (Op : Node_Id) return Boolean; + -- Operand is safe if it cannot overlap part of the target of the + -- operation. If the operand and the target are identical, the operand + -- is safe. The operand can be empty in the case of negation. + + function Is_Unaliased (N : Node_Id) return Boolean; + -- Check that N is a stand-alone entity + + ------------------ + -- Is_Unaliased -- + ------------------ + + function Is_Unaliased (N : Node_Id) return Boolean is + begin + return + Is_Entity_Name (N) + and then No (Address_Clause (Entity (N))) + and then No (Renamed_Object (Entity (N))); + end Is_Unaliased; + + --------------------- + -- Is_Safe_Operand -- + --------------------- + + function Is_Safe_Operand (Op : Node_Id) return Boolean is + begin + if No (Op) then + return True; + + elsif Is_Entity_Name (Op) then + return Is_Unaliased (Op); + + elsif Nkind_In (Op, N_Indexed_Component, N_Selected_Component) then + return Is_Unaliased (Prefix (Op)); + + elsif Nkind (Op) = N_Slice then + return + Is_Unaliased (Prefix (Op)) + and then Entity (Prefix (Op)) /= Target; + + elsif Nkind (Op) = N_Op_Not then + return Is_Safe_Operand (Right_Opnd (Op)); + + else + return False; + end if; + end Is_Safe_Operand; + + -- Start of processing for Safe_In_Place_Array_Op + + begin + -- Skip this processing if the component size is different from system + -- storage unit (since at least for NOT this would cause problems). + + if Component_Size (Etype (Lhs)) /= System_Storage_Unit then + return False; + + -- Cannot do in place stuff if non-standard Boolean representation + + elsif Has_Non_Standard_Rep (Component_Type (Etype (Lhs))) then + return False; + + elsif not Is_Unaliased (Lhs) then + return False; + + else + Target := Entity (Lhs); + return Is_Safe_Operand (Op1) and then Is_Safe_Operand (Op2); + end if; + end Safe_In_Place_Array_Op; + + ----------------------- + -- Tagged_Membership -- + ----------------------- + + -- There are two different cases to consider depending on whether the right + -- operand is a class-wide type or not. If not we just compare the actual + -- tag of the left expr to the target type tag: + -- + -- Left_Expr.Tag = Right_Type'Tag; + -- + -- If it is a class-wide type we use the RT function CW_Membership which is + -- usually implemented by looking in the ancestor tables contained in the + -- dispatch table pointed by Left_Expr.Tag for Typ'Tag + + -- Ada 2005 (AI-251): If it is a class-wide interface type we use the RT + -- function IW_Membership which is usually implemented by looking in the + -- table of abstract interface types plus the ancestor table contained in + -- the dispatch table pointed by Left_Expr.Tag for Typ'Tag + + procedure Tagged_Membership + (N : Node_Id; + SCIL_Node : out Node_Id; + Result : out Node_Id) + is + Left : constant Node_Id := Left_Opnd (N); + Right : constant Node_Id := Right_Opnd (N); + Loc : constant Source_Ptr := Sloc (N); + + Full_R_Typ : Entity_Id; + Left_Type : Entity_Id; + New_Node : Node_Id; + Right_Type : Entity_Id; + Obj_Tag : Node_Id; + + begin + SCIL_Node := Empty; + + -- Handle entities from the limited view + + Left_Type := Available_View (Etype (Left)); + Right_Type := Available_View (Etype (Right)); + + -- In the case where the type is an access type, the test is applied + -- using the designated types (needed in Ada 2012 for implicit anonymous + -- access conversions, for AI05-0149). + + if Is_Access_Type (Right_Type) then + Left_Type := Designated_Type (Left_Type); + Right_Type := Designated_Type (Right_Type); + end if; + + if Is_Class_Wide_Type (Left_Type) then + Left_Type := Root_Type (Left_Type); + end if; + + if Is_Class_Wide_Type (Right_Type) then + Full_R_Typ := Underlying_Type (Root_Type (Right_Type)); + else + Full_R_Typ := Underlying_Type (Right_Type); + end if; + + Obj_Tag := + Make_Selected_Component (Loc, + Prefix => Relocate_Node (Left), + Selector_Name => + New_Occurrence_Of (First_Tag_Component (Left_Type), Loc)); + + if Is_Class_Wide_Type (Right_Type) then + + -- No need to issue a run-time check if we statically know that the + -- result of this membership test is always true. For example, + -- considering the following declarations: + + -- type Iface is interface; + -- type T is tagged null record; + -- type DT is new T and Iface with null record; + + -- Obj1 : T; + -- Obj2 : DT; + + -- These membership tests are always true: + + -- Obj1 in T'Class + -- Obj2 in T'Class; + -- Obj2 in Iface'Class; + + -- We do not need to handle cases where the membership is illegal. + -- For example: + + -- Obj1 in DT'Class; -- Compile time error + -- Obj1 in Iface'Class; -- Compile time error + + if not Is_Class_Wide_Type (Left_Type) + and then (Is_Ancestor (Etype (Right_Type), Left_Type, + Use_Full_View => True) + or else (Is_Interface (Etype (Right_Type)) + and then Interface_Present_In_Ancestor + (Typ => Left_Type, + Iface => Etype (Right_Type)))) + then + Result := New_Occurrence_Of (Standard_True, Loc); + return; + end if; + + -- Ada 2005 (AI-251): Class-wide applied to interfaces + + if Is_Interface (Etype (Class_Wide_Type (Right_Type))) + + -- Support to: "Iface_CW_Typ in Typ'Class" + + or else Is_Interface (Left_Type) + then + -- Issue error if IW_Membership operation not available in a + -- configurable run time setting. + + if not RTE_Available (RE_IW_Membership) then + Error_Msg_CRT + ("dynamic membership test on interface types", N); + Result := Empty; + return; + end if; + + Result := + Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (RE_IW_Membership), Loc), + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => Obj_Tag, + Attribute_Name => Name_Address), + New_Occurrence_Of ( + Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), + Loc))); + + -- Ada 95: Normal case + + else + Build_CW_Membership (Loc, + Obj_Tag_Node => Obj_Tag, + Typ_Tag_Node => + New_Occurrence_Of ( + Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), Loc), + Related_Nod => N, + New_Node => New_Node); + + -- Generate the SCIL node for this class-wide membership test. + -- Done here because the previous call to Build_CW_Membership + -- relocates Obj_Tag. + + if Generate_SCIL then + SCIL_Node := Make_SCIL_Membership_Test (Sloc (N)); + Set_SCIL_Entity (SCIL_Node, Etype (Right_Type)); + Set_SCIL_Tag_Value (SCIL_Node, Obj_Tag); + end if; + + Result := New_Node; + end if; + + -- Right_Type is not a class-wide type + + else + -- No need to check the tag of the object if Right_Typ is abstract + + if Is_Abstract_Type (Right_Type) then + Result := New_Occurrence_Of (Standard_False, Loc); + + else + Result := + Make_Op_Eq (Loc, + Left_Opnd => Obj_Tag, + Right_Opnd => + New_Occurrence_Of + (Node (First_Elmt (Access_Disp_Table (Full_R_Typ))), Loc)); + end if; + end if; + end Tagged_Membership; + + ------------------------------ + -- Unary_Op_Validity_Checks -- + ------------------------------ + + procedure Unary_Op_Validity_Checks (N : Node_Id) is + begin + if Validity_Checks_On and Validity_Check_Operands then + Ensure_Valid (Right_Opnd (N)); + end if; + end Unary_Op_Validity_Checks; + +end Exp_Ch4;