Mercurial > hg > CbC > CbC_gcc
diff gcc/ada/exp_ch6.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_ch6.adb Fri Oct 27 22:46:09 2017 +0900 @@ -0,0 +1,9380 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ C H 6 -- +-- -- +-- 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 Contracts; use Contracts; +with Debug; use Debug; +with Einfo; use Einfo; +with Errout; use Errout; +with Elists; use Elists; +with Expander; use Expander; +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_Ch7; use Exp_Ch7; +with Exp_Ch9; use Exp_Ch9; +with Exp_Dbug; use Exp_Dbug; +with Exp_Disp; use Exp_Disp; +with Exp_Dist; use Exp_Dist; +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 Itypes; use Itypes; +with Lib; use Lib; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Restrict; use Restrict; +with Rident; use Rident; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Aux; use Sem_Aux; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch8; use Sem_Ch8; +with Sem_Ch12; use Sem_Ch12; +with Sem_Ch13; use Sem_Ch13; +with Sem_Dim; use Sem_Dim; +with Sem_Disp; use Sem_Disp; +with Sem_Dist; use Sem_Dist; +with Sem_Eval; use Sem_Eval; +with Sem_Mech; use Sem_Mech; +with Sem_Res; use Sem_Res; +with Sem_SCIL; use Sem_SCIL; +with Sem_Util; use Sem_Util; +with Sinfo; use Sinfo; +with Snames; use Snames; +with Stand; use Stand; +with Tbuild; use Tbuild; +with Uintp; use Uintp; +with Validsw; use Validsw; + +package body Exp_Ch6 is + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Add_Access_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Return_Object : Node_Id; + Is_Access : Boolean := False); + -- Ada 2005 (AI-318-02): Apply the Unrestricted_Access attribute to the + -- object name given by Return_Object and add the attribute to the end of + -- the actual parameter list associated with the build-in-place function + -- call denoted by Function_Call. However, if Is_Access is True, then + -- Return_Object is already an access expression, in which case it's passed + -- along directly to the build-in-place function. Finally, if Return_Object + -- is empty, then pass a null literal as the actual. + + procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Alloc_Form : BIP_Allocation_Form := Unspecified; + Alloc_Form_Exp : Node_Id := Empty; + Pool_Actual : Node_Id := Make_Null (No_Location)); + -- Ada 2005 (AI-318-02): Add the actuals needed for a build-in-place + -- function call that returns a caller-unknown-size result (BIP_Alloc_Form + -- and BIP_Storage_Pool). If Alloc_Form_Exp is present, then use it, + -- otherwise pass a literal corresponding to the Alloc_Form parameter + -- (which must not be Unspecified in that case). Pool_Actual is the + -- parameter to pass to BIP_Storage_Pool. + + procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call : Node_Id; + Func_Id : Entity_Id; + Ptr_Typ : Entity_Id := Empty; + Master_Exp : Node_Id := Empty); + -- Ada 2005 (AI-318-02): If the result type of a build-in-place call needs + -- finalization actions, add an actual parameter which is a pointer to the + -- finalization master of the caller. If Master_Exp is not Empty, then that + -- will be passed as the actual. Otherwise, if Ptr_Typ is left Empty, this + -- will result in an automatic "null" value for the actual. + + procedure Add_Task_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Master_Actual : Node_Id; + Chain : Node_Id := Empty); + -- Ada 2005 (AI-318-02): For a build-in-place call, if the result type + -- contains tasks, add two actual parameters: the master, and a pointer to + -- the caller's activation chain. Master_Actual is the actual parameter + -- expression to pass for the master. In most cases, this is the current + -- master (_master). The two exceptions are: If the function call is the + -- initialization expression for an allocator, we pass the master of the + -- access type. If the function call is the initialization expression for a + -- return object, we pass along the master passed in by the caller. In most + -- contexts, the activation chain to pass is the local one, which is + -- indicated by No (Chain). However, in an allocator, the caller passes in + -- the activation Chain. Note: Master_Actual can be Empty, but only if + -- there are no tasks. + + function Caller_Known_Size + (Func_Call : Node_Id; + Result_Subt : Entity_Id) return Boolean; + -- True if result subtype is definite, or has a size that does not require + -- secondary stack usage (i.e. no variant part or components whose type + -- depends on discriminants). In particular, untagged types with only + -- access discriminants do not require secondary stack use. Note we must + -- always use the secondary stack for dispatching-on-result calls. + + procedure Check_Overriding_Operation (Subp : Entity_Id); + -- Subp is a dispatching operation. Check whether it may override an + -- inherited private operation, in which case its DT entry is that of + -- the hidden operation, not the one it may have received earlier. + -- This must be done before emitting the code to set the corresponding + -- DT to the address of the subprogram. The actual placement of Subp in + -- the proper place in the list of primitive operations is done in + -- Declare_Inherited_Private_Subprograms, which also has to deal with + -- implicit operations. This duplication is unavoidable for now??? + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id); + -- This procedure is called only if the subprogram body N, whose spec + -- has the given entity Spec, contains a parameterless recursive call. + -- It attempts to generate runtime code to detect if this a case of + -- infinite recursion. + -- + -- The body is scanned to determine dependencies. If the only external + -- dependencies are on a small set of scalar variables, then the values + -- of these variables are captured on entry to the subprogram, and if + -- the values are not changed for the call, we know immediately that + -- we have an infinite recursion. + + procedure Expand_Actuals + (N : Node_Id; + Subp : Entity_Id; + Post_Call : out List_Id); + -- Return a list of actions to take place after the call in Post_Call. The + -- call will later be rewritten as an Expression_With_Actions, with the + -- Post_Call actions inserted, and the call inside. + -- + -- For each actual of an in-out or out parameter which is a numeric (view) + -- conversion of the form T (A), where A denotes a variable, we insert the + -- declaration: + -- + -- Temp : T[ := T (A)]; + -- + -- prior to the call. Then we replace the actual with a reference to Temp, + -- and append the assignment: + -- + -- A := TypeA (Temp); + -- + -- after the call. Here TypeA is the actual type of variable A. For out + -- parameters, the initial declaration has no expression. If A is not an + -- entity name, we generate instead: + -- + -- Var : TypeA renames A; + -- Temp : T := Var; -- omitting expression for out parameter. + -- ... + -- Var := TypeA (Temp); + -- + -- For other in-out parameters, we emit the required constraint checks + -- before and/or after the call. + -- + -- For all parameter modes, actuals that denote components and slices of + -- packed arrays are expanded into suitable temporaries. + -- + -- For non-scalar objects that are possibly unaligned, add call by copy + -- code (copy in for IN and IN OUT, copy out for OUT and IN OUT). + -- + -- For OUT and IN OUT parameters, add predicate checks after the call + -- based on the predicates of the actual type. + + procedure Expand_Call_Helper (N : Node_Id; Post_Call : out List_Id); + -- Does the main work of Expand_Call. Post_Call is as for Expand_Actuals. + + procedure Expand_Ctrl_Function_Call (N : Node_Id); + -- N is a function call which returns a controlled object. Transform the + -- call into a temporary which retrieves the returned object from the + -- secondary stack using 'reference. + + procedure Expand_Non_Function_Return (N : Node_Id); + -- Expand a simple return statement found in a procedure body, entry body, + -- accept statement, or an extended return statement. Note that all non- + -- function returns are simple return statements. + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) return Node_Id; + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id); + -- A call to a protected subprogram within the protected object may appear + -- as a regular call. The list of actuals must be expanded to contain a + -- reference to the object itself, and the call becomes a call to the + -- corresponding protected subprogram. + + procedure Expand_Simple_Function_Return (N : Node_Id); + -- Expand simple return from function. In the case where we are returning + -- from a function body this is called by Expand_N_Simple_Return_Statement. + + function Has_Unconstrained_Access_Discriminants + (Subtyp : Entity_Id) return Boolean; + -- Returns True if the given subtype is unconstrained and has one or more + -- access discriminants. + + procedure Insert_Post_Call_Actions (N : Node_Id; Post_Call : List_Id); + -- Insert the Post_Call list previously produced by routine Expand_Actuals + -- or Expand_Call_Helper into the tree. + + procedure Replace_Renaming_Declaration_Id + (New_Decl : Node_Id; + Orig_Decl : Node_Id); + -- Replace the internal identifier of the new renaming declaration New_Decl + -- with the identifier of its original declaration Orig_Decl exchanging the + -- entities containing their defining identifiers to ensure the correct + -- replacement of the object declaration by the object renaming declaration + -- to avoid homograph conflicts (since the object declaration's defining + -- identifier was already entered in the current scope). The Next_Entity + -- links of the two entities are also swapped since the entities are part + -- of the return scope's entity list and the list structure would otherwise + -- be corrupted. The homonym chain is preserved as well. + + procedure Rewrite_Function_Call_For_C (N : Node_Id); + -- When generating C code, replace a call to a function that returns an + -- array into the generated procedure with an additional out parameter. + + procedure Set_Enclosing_Sec_Stack_Return (N : Node_Id); + -- N is a return statement for a function that returns its result on the + -- secondary stack. This sets the Sec_Stack_Needed_For_Return flag on the + -- function and all blocks and loops that the return statement is jumping + -- out of. This ensures that the secondary stack is not released; otherwise + -- the function result would be reclaimed before returning to the caller. + + ---------------------------------------------- + -- Add_Access_Actual_To_Build_In_Place_Call -- + ---------------------------------------------- + + procedure Add_Access_Actual_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Return_Object : Node_Id; + Is_Access : Boolean := False) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Obj_Address : Node_Id; + Obj_Acc_Formal : Entity_Id; + + begin + -- Locate the implicit access parameter in the called function + + Obj_Acc_Formal := Build_In_Place_Formal (Function_Id, BIP_Object_Access); + + -- If no return object is provided, then pass null + + if not Present (Return_Object) then + Obj_Address := Make_Null (Loc); + Set_Parent (Obj_Address, Function_Call); + + -- If Return_Object is already an expression of an access type, then use + -- it directly, since it must be an access value denoting the return + -- object, and couldn't possibly be the return object itself. + + elsif Is_Access then + Obj_Address := Return_Object; + Set_Parent (Obj_Address, Function_Call); + + -- Apply Unrestricted_Access to caller's return object + + else + Obj_Address := + Make_Attribute_Reference (Loc, + Prefix => Return_Object, + Attribute_Name => Name_Unrestricted_Access); + + Set_Parent (Return_Object, Obj_Address); + Set_Parent (Obj_Address, Function_Call); + end if; + + Analyze_And_Resolve (Obj_Address, Etype (Obj_Acc_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call (Function_Call, Obj_Acc_Formal, Obj_Address); + end Add_Access_Actual_To_Build_In_Place_Call; + + ------------------------------------------------------ + -- Add_Unconstrained_Actuals_To_Build_In_Place_Call -- + ------------------------------------------------------ + + procedure Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Alloc_Form : BIP_Allocation_Form := Unspecified; + Alloc_Form_Exp : Node_Id := Empty; + Pool_Actual : Node_Id := Make_Null (No_Location)) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Alloc_Form_Actual : Node_Id; + Alloc_Form_Formal : Node_Id; + Pool_Formal : Node_Id; + + begin + -- The allocation form generally doesn't need to be passed in the case + -- of a constrained result subtype, since normally the caller performs + -- the allocation in that case. However this formal is still needed in + -- the case where the function has a tagged result, because generally + -- such functions can be called in a dispatching context and such calls + -- must be handled like calls to class-wide functions. + + if Is_Constrained (Underlying_Type (Etype (Function_Id))) + and then not Is_Tagged_Type (Underlying_Type (Etype (Function_Id))) + then + return; + end if; + + -- Locate the implicit allocation form parameter in the called function. + -- Maybe it would be better for each implicit formal of a build-in-place + -- function to have a flag or a Uint attribute to identify it. ??? + + Alloc_Form_Formal := Build_In_Place_Formal (Function_Id, BIP_Alloc_Form); + + if Present (Alloc_Form_Exp) then + pragma Assert (Alloc_Form = Unspecified); + + Alloc_Form_Actual := Alloc_Form_Exp; + + else + pragma Assert (Alloc_Form /= Unspecified); + + Alloc_Form_Actual := + Make_Integer_Literal (Loc, + Intval => UI_From_Int (BIP_Allocation_Form'Pos (Alloc_Form))); + end if; + + Analyze_And_Resolve (Alloc_Form_Actual, Etype (Alloc_Form_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call + (Function_Call, Alloc_Form_Formal, Alloc_Form_Actual); + + -- Pass the Storage_Pool parameter. This parameter is omitted on + -- ZFP as those targets do not support pools. + + if RTE_Available (RE_Root_Storage_Pool_Ptr) then + Pool_Formal := Build_In_Place_Formal (Function_Id, BIP_Storage_Pool); + Analyze_And_Resolve (Pool_Actual, Etype (Pool_Formal)); + Add_Extra_Actual_To_Call + (Function_Call, Pool_Formal, Pool_Actual); + end if; + end Add_Unconstrained_Actuals_To_Build_In_Place_Call; + + ----------------------------------------------------------- + -- Add_Finalization_Master_Actual_To_Build_In_Place_Call -- + ----------------------------------------------------------- + + procedure Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call : Node_Id; + Func_Id : Entity_Id; + Ptr_Typ : Entity_Id := Empty; + Master_Exp : Node_Id := Empty) + is + begin + if not Needs_BIP_Finalization_Master (Func_Id) then + return; + end if; + + declare + Formal : constant Entity_Id := + Build_In_Place_Formal (Func_Id, BIP_Finalization_Master); + Loc : constant Source_Ptr := Sloc (Func_Call); + + Actual : Node_Id; + Desig_Typ : Entity_Id; + + begin + -- If there is a finalization master actual, such as the implicit + -- finalization master of an enclosing build-in-place function, + -- then this must be added as an extra actual of the call. + + if Present (Master_Exp) then + Actual := Master_Exp; + + -- Case where the context does not require an actual master + + elsif No (Ptr_Typ) then + Actual := Make_Null (Loc); + + else + Desig_Typ := Directly_Designated_Type (Ptr_Typ); + + -- Check for a library-level access type whose designated type has + -- suppressed finalization or the access type is subject to pragma + -- No_Heap_Finalization. Such an access type lacks a master. Pass + -- a null actual to callee in order to signal a missing master. + + if Is_Library_Level_Entity (Ptr_Typ) + and then (Finalize_Storage_Only (Desig_Typ) + or else No_Heap_Finalization (Ptr_Typ)) + then + Actual := Make_Null (Loc); + + -- Types in need of finalization actions + + elsif Needs_Finalization (Desig_Typ) then + + -- The general mechanism of creating finalization masters for + -- anonymous access types is disabled by default, otherwise + -- finalization masters will pop all over the place. Such types + -- use context-specific masters. + + if Ekind (Ptr_Typ) = E_Anonymous_Access_Type + and then No (Finalization_Master (Ptr_Typ)) + then + Build_Anonymous_Master (Ptr_Typ); + end if; + + -- Access-to-controlled types should always have a master + + pragma Assert (Present (Finalization_Master (Ptr_Typ))); + + Actual := + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (Finalization_Master (Ptr_Typ), Loc), + Attribute_Name => Name_Unrestricted_Access); + + -- Tagged types + + else + Actual := Make_Null (Loc); + end if; + end if; + + Analyze_And_Resolve (Actual, Etype (Formal)); + + -- Build the parameter association for the new actual and add it to + -- the end of the function's actuals. + + Add_Extra_Actual_To_Call (Func_Call, Formal, Actual); + end; + end Add_Finalization_Master_Actual_To_Build_In_Place_Call; + + ------------------------------ + -- Add_Extra_Actual_To_Call -- + ------------------------------ + + procedure Add_Extra_Actual_To_Call + (Subprogram_Call : Node_Id; + Extra_Formal : Entity_Id; + Extra_Actual : Node_Id) + is + Loc : constant Source_Ptr := Sloc (Subprogram_Call); + Param_Assoc : Node_Id; + + begin + Param_Assoc := + Make_Parameter_Association (Loc, + Selector_Name => New_Occurrence_Of (Extra_Formal, Loc), + Explicit_Actual_Parameter => Extra_Actual); + + Set_Parent (Param_Assoc, Subprogram_Call); + Set_Parent (Extra_Actual, Param_Assoc); + + if Present (Parameter_Associations (Subprogram_Call)) then + if Nkind (Last (Parameter_Associations (Subprogram_Call))) = + N_Parameter_Association + then + + -- Find last named actual, and append + + declare + L : Node_Id; + begin + L := First_Actual (Subprogram_Call); + while Present (L) loop + if No (Next_Actual (L)) then + Set_Next_Named_Actual (Parent (L), Extra_Actual); + exit; + end if; + Next_Actual (L); + end loop; + end; + + else + Set_First_Named_Actual (Subprogram_Call, Extra_Actual); + end if; + + Append (Param_Assoc, To => Parameter_Associations (Subprogram_Call)); + + else + Set_Parameter_Associations (Subprogram_Call, New_List (Param_Assoc)); + Set_First_Named_Actual (Subprogram_Call, Extra_Actual); + end if; + end Add_Extra_Actual_To_Call; + + --------------------------------------------- + -- Add_Task_Actuals_To_Build_In_Place_Call -- + --------------------------------------------- + + procedure Add_Task_Actuals_To_Build_In_Place_Call + (Function_Call : Node_Id; + Function_Id : Entity_Id; + Master_Actual : Node_Id; + Chain : Node_Id := Empty) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Result_Subt : constant Entity_Id := + Available_View (Etype (Function_Id)); + Actual : Node_Id; + Chain_Actual : Node_Id; + Chain_Formal : Node_Id; + Master_Formal : Node_Id; + + begin + -- No such extra parameters are needed if there are no tasks + + if not Has_Task (Result_Subt) then + return; + end if; + + Actual := Master_Actual; + + -- Use a dummy _master actual in case of No_Task_Hierarchy + + if Restriction_Active (No_Task_Hierarchy) then + Actual := New_Occurrence_Of (RTE (RE_Library_Task_Level), Loc); + + -- In the case where we use the master associated with an access type, + -- the actual is an entity and requires an explicit reference. + + elsif Nkind (Actual) = N_Defining_Identifier then + Actual := New_Occurrence_Of (Actual, Loc); + end if; + + -- Locate the implicit master parameter in the called function + + Master_Formal := Build_In_Place_Formal (Function_Id, BIP_Task_Master); + Analyze_And_Resolve (Actual, Etype (Master_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call (Function_Call, Master_Formal, Actual); + + -- Locate the implicit activation chain parameter in the called function + + Chain_Formal := + Build_In_Place_Formal (Function_Id, BIP_Activation_Chain); + + -- Create the actual which is a pointer to the current activation chain + + if No (Chain) then + Chain_Actual := + Make_Attribute_Reference (Loc, + Prefix => Make_Identifier (Loc, Name_uChain), + Attribute_Name => Name_Unrestricted_Access); + + -- Allocator case; make a reference to the Chain passed in by the caller + + else + Chain_Actual := + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Chain, Loc), + Attribute_Name => Name_Unrestricted_Access); + end if; + + Analyze_And_Resolve (Chain_Actual, Etype (Chain_Formal)); + + -- Build the parameter association for the new actual and add it to the + -- end of the function's actuals. + + Add_Extra_Actual_To_Call (Function_Call, Chain_Formal, Chain_Actual); + end Add_Task_Actuals_To_Build_In_Place_Call; + + ----------------------- + -- BIP_Formal_Suffix -- + ----------------------- + + function BIP_Formal_Suffix (Kind : BIP_Formal_Kind) return String is + begin + case Kind is + when BIP_Alloc_Form => + return "BIPalloc"; + + when BIP_Storage_Pool => + return "BIPstoragepool"; + + when BIP_Finalization_Master => + return "BIPfinalizationmaster"; + + when BIP_Task_Master => + return "BIPtaskmaster"; + + when BIP_Activation_Chain => + return "BIPactivationchain"; + + when BIP_Object_Access => + return "BIPaccess"; + end case; + end BIP_Formal_Suffix; + + --------------------------- + -- Build_In_Place_Formal -- + --------------------------- + + function Build_In_Place_Formal + (Func : Entity_Id; + Kind : BIP_Formal_Kind) return Entity_Id + is + Formal_Name : constant Name_Id := + New_External_Name + (Chars (Func), BIP_Formal_Suffix (Kind)); + Extra_Formal : Entity_Id := Extra_Formals (Func); + + begin + -- Maybe it would be better for each implicit formal of a build-in-place + -- function to have a flag or a Uint attribute to identify it. ??? + + -- The return type in the function declaration may have been a limited + -- view, and the extra formals for the function were not generated at + -- that point. At the point of call the full view must be available and + -- the extra formals can be created. + + if No (Extra_Formal) then + Create_Extra_Formals (Func); + Extra_Formal := Extra_Formals (Func); + end if; + + loop + pragma Assert (Present (Extra_Formal)); + exit when Chars (Extra_Formal) = Formal_Name; + + Next_Formal_With_Extras (Extra_Formal); + end loop; + + return Extra_Formal; + end Build_In_Place_Formal; + + ------------------------------- + -- Build_Procedure_Body_Form -- + ------------------------------- + + function Build_Procedure_Body_Form + (Func_Id : Entity_Id; + Func_Body : Node_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (Func_Body); + + Proc_Decl : constant Node_Id := + Next (Unit_Declaration_Node (Func_Id)); + -- It is assumed that the next node following the declaration of the + -- corresponding subprogram spec is the declaration of the procedure + -- form. + + Proc_Id : constant Entity_Id := Defining_Entity (Proc_Decl); + + procedure Replace_Returns (Param_Id : Entity_Id; Stmts : List_Id); + -- Replace each return statement found in the list Stmts with an + -- assignment of the return expression to parameter Param_Id. + + --------------------- + -- Replace_Returns -- + --------------------- + + procedure Replace_Returns (Param_Id : Entity_Id; Stmts : List_Id) is + Stmt : Node_Id; + + begin + Stmt := First (Stmts); + while Present (Stmt) loop + if Nkind (Stmt) = N_Block_Statement then + Replace_Returns (Param_Id, + Statements (Handled_Statement_Sequence (Stmt))); + + elsif Nkind (Stmt) = N_Case_Statement then + declare + Alt : Node_Id; + begin + Alt := First (Alternatives (Stmt)); + while Present (Alt) loop + Replace_Returns (Param_Id, Statements (Alt)); + Next (Alt); + end loop; + end; + + elsif Nkind (Stmt) = N_Extended_Return_Statement then + declare + Ret_Obj : constant Entity_Id := + Defining_Entity + (First (Return_Object_Declarations (Stmt))); + Assign : constant Node_Id := + Make_Assignment_Statement (Sloc (Stmt), + Name => + New_Occurrence_Of (Param_Id, Loc), + Expression => + New_Occurrence_Of (Ret_Obj, Sloc (Stmt))); + Stmts : List_Id; + + begin + -- The extended return may just contain the declaration + + if Present (Handled_Statement_Sequence (Stmt)) then + Stmts := Statements (Handled_Statement_Sequence (Stmt)); + else + Stmts := New_List; + end if; + + Set_Assignment_OK (Name (Assign)); + + Rewrite (Stmt, + Make_Block_Statement (Sloc (Stmt), + Declarations => + Return_Object_Declarations (Stmt), + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Stmts))); + + Replace_Returns (Param_Id, Stmts); + + Append_To (Stmts, Assign); + Append_To (Stmts, Make_Simple_Return_Statement (Loc)); + end; + + elsif Nkind (Stmt) = N_If_Statement then + Replace_Returns (Param_Id, Then_Statements (Stmt)); + Replace_Returns (Param_Id, Else_Statements (Stmt)); + + declare + Part : Node_Id; + begin + Part := First (Elsif_Parts (Stmt)); + while Present (Part) loop + Replace_Returns (Param_Id, Then_Statements (Part)); + Next (Part); + end loop; + end; + + elsif Nkind (Stmt) = N_Loop_Statement then + Replace_Returns (Param_Id, Statements (Stmt)); + + elsif Nkind (Stmt) = N_Simple_Return_Statement then + + -- Generate: + -- Param := Expr; + -- return; + + Rewrite (Stmt, + Make_Assignment_Statement (Sloc (Stmt), + Name => New_Occurrence_Of (Param_Id, Loc), + Expression => Relocate_Node (Expression (Stmt)))); + + Insert_After (Stmt, Make_Simple_Return_Statement (Loc)); + + -- Skip the added return + + Next (Stmt); + end if; + + Next (Stmt); + end loop; + end Replace_Returns; + + -- Local variables + + Stmts : List_Id; + New_Body : Node_Id; + + -- Start of processing for Build_Procedure_Body_Form + + begin + -- This routine replaces the original function body: + + -- function F (...) return Array_Typ is + -- begin + -- ... + -- return Something; + -- end F; + + -- with the following: + + -- procedure P (..., Result : out Array_Typ) is + -- begin + -- ... + -- Result := Something; + -- end P; + + Stmts := + Statements (Handled_Statement_Sequence (Func_Body)); + Replace_Returns (Last_Entity (Proc_Id), Stmts); + + New_Body := + Make_Subprogram_Body (Loc, + Specification => + Copy_Subprogram_Spec (Specification (Proc_Decl)), + Declarations => Declarations (Func_Body), + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Stmts)); + + -- If the function is a generic instance, so is the new procedure. + -- Set flag accordingly so that the proper renaming declarations are + -- generated. + + Set_Is_Generic_Instance (Proc_Id, Is_Generic_Instance (Func_Id)); + return New_Body; + end Build_Procedure_Body_Form; + + ----------------------- + -- Caller_Known_Size -- + ----------------------- + + function Caller_Known_Size + (Func_Call : Node_Id; + Result_Subt : Entity_Id) return Boolean + is + begin + return + (Is_Definite_Subtype (Underlying_Type (Result_Subt)) + and then No (Controlling_Argument (Func_Call))) + or else not Requires_Transient_Scope (Underlying_Type (Result_Subt)); + end Caller_Known_Size; + + -------------------------------- + -- Check_Overriding_Operation -- + -------------------------------- + + procedure Check_Overriding_Operation (Subp : Entity_Id) is + Typ : constant Entity_Id := Find_Dispatching_Type (Subp); + Op_List : constant Elist_Id := Primitive_Operations (Typ); + Op_Elmt : Elmt_Id; + Prim_Op : Entity_Id; + Par_Op : Entity_Id; + + begin + if Is_Derived_Type (Typ) + and then not Is_Private_Type (Typ) + and then In_Open_Scopes (Scope (Etype (Typ))) + and then Is_Base_Type (Typ) + then + -- Subp overrides an inherited private operation if there is an + -- inherited operation with a different name than Subp (see + -- Derive_Subprogram) whose Alias is a hidden subprogram with the + -- same name as Subp. + + Op_Elmt := First_Elmt (Op_List); + while Present (Op_Elmt) loop + Prim_Op := Node (Op_Elmt); + Par_Op := Alias (Prim_Op); + + if Present (Par_Op) + and then not Comes_From_Source (Prim_Op) + and then Chars (Prim_Op) /= Chars (Par_Op) + and then Chars (Par_Op) = Chars (Subp) + and then Is_Hidden (Par_Op) + and then Type_Conformant (Prim_Op, Subp) + then + Set_DT_Position_Value (Subp, DT_Position (Prim_Op)); + end if; + + Next_Elmt (Op_Elmt); + end loop; + end if; + end Check_Overriding_Operation; + + ------------------------------- + -- Detect_Infinite_Recursion -- + ------------------------------- + + procedure Detect_Infinite_Recursion (N : Node_Id; Spec : Entity_Id) is + Loc : constant Source_Ptr := Sloc (N); + + Var_List : constant Elist_Id := New_Elmt_List; + -- List of globals referenced by body of procedure + + Call_List : constant Elist_Id := New_Elmt_List; + -- List of recursive calls in body of procedure + + Shad_List : constant Elist_Id := New_Elmt_List; + -- List of entity id's for entities created to capture the value of + -- referenced globals on entry to the procedure. + + Scop : constant Uint := Scope_Depth (Spec); + -- This is used to record the scope depth of the current procedure, so + -- that we can identify global references. + + Max_Vars : constant := 4; + -- Do not test more than four global variables + + Count_Vars : Natural := 0; + -- Count variables found so far + + Var : Entity_Id; + Elm : Elmt_Id; + Ent : Entity_Id; + Call : Elmt_Id; + Decl : Node_Id; + Test : Node_Id; + Elm1 : Elmt_Id; + Elm2 : Elmt_Id; + Last : Node_Id; + + function Process (Nod : Node_Id) return Traverse_Result; + -- Function to traverse the subprogram body (using Traverse_Func) + + ------------- + -- Process -- + ------------- + + function Process (Nod : Node_Id) return Traverse_Result is + begin + -- Procedure call + + if Nkind (Nod) = N_Procedure_Call_Statement then + + -- Case of one of the detected recursive calls + + if Is_Entity_Name (Name (Nod)) + and then Has_Recursive_Call (Entity (Name (Nod))) + and then Entity (Name (Nod)) = Spec + then + Append_Elmt (Nod, Call_List); + return Skip; + + -- Any other procedure call may have side effects + + else + return Abandon; + end if; + + -- A call to a pure function can always be ignored + + elsif Nkind (Nod) = N_Function_Call + and then Is_Entity_Name (Name (Nod)) + and then Is_Pure (Entity (Name (Nod))) + then + return Skip; + + -- Case of an identifier reference + + elsif Nkind (Nod) = N_Identifier then + Ent := Entity (Nod); + + -- If no entity, then ignore the reference + + -- Not clear why this can happen. To investigate, remove this + -- test and look at the crash that occurs here in 3401-004 ??? + + if No (Ent) then + return Skip; + + -- Ignore entities with no Scope, again not clear how this + -- can happen, to investigate, look at 4108-008 ??? + + elsif No (Scope (Ent)) then + return Skip; + + -- Ignore the reference if not to a more global object + + elsif Scope_Depth (Scope (Ent)) >= Scop then + return Skip; + + -- References to types, exceptions and constants are always OK + + elsif Is_Type (Ent) + or else Ekind (Ent) = E_Exception + or else Ekind (Ent) = E_Constant + then + return Skip; + + -- If other than a non-volatile scalar variable, we have some + -- kind of global reference (e.g. to a function) that we cannot + -- deal with so we forget the attempt. + + elsif Ekind (Ent) /= E_Variable + or else not Is_Scalar_Type (Etype (Ent)) + or else Treat_As_Volatile (Ent) + then + return Abandon; + + -- Otherwise we have a reference to a global scalar + + else + -- Loop through global entities already detected + + Elm := First_Elmt (Var_List); + loop + -- If not detected before, record this new global reference + + if No (Elm) then + Count_Vars := Count_Vars + 1; + + if Count_Vars <= Max_Vars then + Append_Elmt (Entity (Nod), Var_List); + else + return Abandon; + end if; + + exit; + + -- If recorded before, ignore + + elsif Node (Elm) = Entity (Nod) then + return Skip; + + -- Otherwise keep looking + + else + Next_Elmt (Elm); + end if; + end loop; + + return Skip; + end if; + + -- For all other node kinds, recursively visit syntactic children + + else + return OK; + end if; + end Process; + + function Traverse_Body is new Traverse_Func (Process); + + -- Start of processing for Detect_Infinite_Recursion + + begin + -- Do not attempt detection in No_Implicit_Conditional mode, since we + -- won't be able to generate the code to handle the recursion in any + -- case. + + if Restriction_Active (No_Implicit_Conditionals) then + return; + end if; + + -- Otherwise do traversal and quit if we get abandon signal + + if Traverse_Body (N) = Abandon then + return; + + -- We must have a call, since Has_Recursive_Call was set. If not just + -- ignore (this is only an error check, so if we have a funny situation, + -- due to bugs or errors, we do not want to bomb). + + elsif Is_Empty_Elmt_List (Call_List) then + return; + end if; + + -- Here is the case where we detect recursion at compile time + + -- Push our current scope for analyzing the declarations and code that + -- we will insert for the checking. + + Push_Scope (Spec); + + -- This loop builds temporary variables for each of the referenced + -- globals, so that at the end of the loop the list Shad_List contains + -- these temporaries in one-to-one correspondence with the elements in + -- Var_List. + + Last := Empty; + Elm := First_Elmt (Var_List); + while Present (Elm) loop + Var := Node (Elm); + Ent := Make_Temporary (Loc, 'S'); + Append_Elmt (Ent, Shad_List); + + -- Insert a declaration for this temporary at the start of the + -- declarations for the procedure. The temporaries are declared as + -- constant objects initialized to the current values of the + -- corresponding temporaries. + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => New_Occurrence_Of (Etype (Var), Loc), + Constant_Present => True, + Expression => New_Occurrence_Of (Var, Loc)); + + if No (Last) then + Prepend (Decl, Declarations (N)); + else + Insert_After (Last, Decl); + end if; + + Last := Decl; + Analyze (Decl); + Next_Elmt (Elm); + end loop; + + -- Loop through calls + + Call := First_Elmt (Call_List); + while Present (Call) loop + + -- Build a predicate expression of the form + + -- True + -- and then global1 = temp1 + -- and then global2 = temp2 + -- ... + + -- This predicate determines if any of the global values + -- referenced by the procedure have changed since the + -- current call, if not an infinite recursion is assured. + + Test := New_Occurrence_Of (Standard_True, Loc); + + Elm1 := First_Elmt (Var_List); + Elm2 := First_Elmt (Shad_List); + while Present (Elm1) loop + Test := + Make_And_Then (Loc, + Left_Opnd => Test, + Right_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => New_Occurrence_Of (Node (Elm1), Loc), + Right_Opnd => New_Occurrence_Of (Node (Elm2), Loc))); + + Next_Elmt (Elm1); + Next_Elmt (Elm2); + end loop; + + -- Now we replace the call with the sequence + + -- if no-changes (see above) then + -- raise Storage_Error; + -- else + -- original-call + -- end if; + + Rewrite (Node (Call), + Make_If_Statement (Loc, + Condition => Test, + Then_Statements => New_List ( + Make_Raise_Storage_Error (Loc, + Reason => SE_Infinite_Recursion)), + + Else_Statements => New_List ( + Relocate_Node (Node (Call))))); + + Analyze (Node (Call)); + + Next_Elmt (Call); + end loop; + + -- Remove temporary scope stack entry used for analysis + + Pop_Scope; + end Detect_Infinite_Recursion; + + -------------------- + -- Expand_Actuals -- + -------------------- + + procedure Expand_Actuals + (N : Node_Id; + Subp : Entity_Id; + Post_Call : out List_Id) + is + Loc : constant Source_Ptr := Sloc (N); + Actual : Node_Id; + Formal : Entity_Id; + N_Node : Node_Id; + E_Actual : Entity_Id; + E_Formal : Entity_Id; + + procedure Add_Call_By_Copy_Code; + -- For cases where the parameter must be passed by copy, this routine + -- generates a temporary variable into which the actual is copied and + -- then passes this as the parameter. For an OUT or IN OUT parameter, + -- an assignment is also generated to copy the result back. The call + -- also takes care of any constraint checks required for the type + -- conversion case (on both the way in and the way out). + + procedure Add_Simple_Call_By_Copy_Code; + -- This is similar to the above, but is used in cases where we know + -- that all that is needed is to simply create a temporary and copy + -- the value in and out of the temporary. + + procedure Add_Validation_Call_By_Copy_Code (Act : Node_Id); + -- Perform copy-back for actual parameter Act which denotes a validation + -- variable. + + procedure Check_Fortran_Logical; + -- A value of type Logical that is passed through a formal parameter + -- must be normalized because .TRUE. usually does not have the same + -- representation as True. We assume that .FALSE. = False = 0. + -- What about functions that return a logical type ??? + + function Is_Legal_Copy return Boolean; + -- Check that an actual can be copied before generating the temporary + -- to be used in the call. If the actual is of a by_reference type then + -- the program is illegal (this can only happen in the presence of + -- rep. clauses that force an incorrect alignment). If the formal is + -- a by_reference parameter imposed by a DEC pragma, emit a warning to + -- the effect that this might lead to unaligned arguments. + + function Make_Var (Actual : Node_Id) return Entity_Id; + -- Returns an entity that refers to the given actual parameter, Actual + -- (not including any type conversion). If Actual is an entity name, + -- then this entity is returned unchanged, otherwise a renaming is + -- created to provide an entity for the actual. + + procedure Reset_Packed_Prefix; + -- The expansion of a packed array component reference is delayed in + -- the context of a call. Now we need to complete the expansion, so we + -- unmark the analyzed bits in all prefixes. + + --------------------------- + -- Add_Call_By_Copy_Code -- + --------------------------- + + procedure Add_Call_By_Copy_Code is + Crep : Boolean; + Expr : Node_Id; + F_Typ : Entity_Id := Etype (Formal); + Indic : Node_Id; + Init : Node_Id; + Temp : Entity_Id; + V_Typ : Entity_Id; + Var : Entity_Id; + + begin + if not Is_Legal_Copy then + return; + end if; + + Temp := Make_Temporary (Loc, 'T', Actual); + + -- Handle formals whose type comes from the limited view + + if From_Limited_With (F_Typ) + and then Has_Non_Limited_View (F_Typ) + then + F_Typ := Non_Limited_View (F_Typ); + end if; + + -- Use formal type for temp, unless formal type is an unconstrained + -- array, in which case we don't have to worry about bounds checks, + -- and we use the actual type, since that has appropriate bounds. + + if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + else + Indic := New_Occurrence_Of (F_Typ, Loc); + end if; + + if Nkind (Actual) = N_Type_Conversion then + V_Typ := Etype (Expression (Actual)); + + -- If the formal is an (in-)out parameter, capture the name + -- of the variable in order to build the post-call assignment. + + Var := Make_Var (Expression (Actual)); + + Crep := not Same_Representation + (F_Typ, Etype (Expression (Actual))); + + else + V_Typ := Etype (Actual); + Var := Make_Var (Actual); + Crep := False; + end if; + + -- Setup initialization for case of in out parameter, or an out + -- parameter where the formal is an unconstrained array (in the + -- latter case, we have to pass in an object with bounds). + + -- If this is an out parameter, the initial copy is wasteful, so as + -- an optimization for the one-dimensional case we extract the + -- bounds of the actual and build an uninitialized temporary of the + -- right size. + + if Ekind (Formal) = E_In_Out_Parameter + or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ)) + then + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + + elsif Ekind (Formal) = E_Out_Parameter + and then Is_Array_Type (F_Typ) + and then Number_Dimensions (F_Typ) = 1 + and then not Has_Non_Null_Base_Init_Proc (F_Typ) + then + -- Actual is a one-dimensional array or slice, and the type + -- requires no initialization. Create a temporary of the + -- right size, but do not copy actual into it (optimization). + + Init := Empty; + Indic := + Make_Subtype_Indication (Loc, + Subtype_Mark => New_Occurrence_Of (F_Typ, Loc), + Constraint => + Make_Index_Or_Discriminant_Constraint (Loc, + Constraints => New_List ( + Make_Range (Loc, + Low_Bound => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Var, Loc), + Attribute_Name => Name_First), + High_Bound => + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Var, Loc), + Attribute_Name => Name_Last))))); + + else + Init := New_Occurrence_Of (Var, Loc); + end if; + + -- An initialization is created for packed conversions as + -- actuals for out parameters to enable Make_Object_Declaration + -- to determine the proper subtype for N_Node. Note that this + -- is wasteful because the extra copying on the call side is + -- not required for such out parameters. ??? + + elsif Ekind (Formal) = E_Out_Parameter + and then Nkind (Actual) = N_Type_Conversion + and then (Is_Bit_Packed_Array (F_Typ) + or else + Is_Bit_Packed_Array (Etype (Expression (Actual)))) + then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + + elsif Ekind (Formal) = E_In_Parameter then + + -- Handle the case in which the actual is a type conversion + + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Init := OK_Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + else + Init := Convert_To (F_Typ, New_Occurrence_Of (Var, Loc)); + end if; + else + Init := New_Occurrence_Of (Var, Loc); + end if; + + else + Init := Empty; + end if; + + N_Node := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => Indic, + Expression => Init); + Set_Assignment_OK (N_Node); + Insert_Action (N, N_Node); + + -- Now, normally the deal here is that we use the defining + -- identifier created by that object declaration. There is + -- one exception to this. In the change of representation case + -- the above declaration will end up looking like: + + -- temp : type := identifier; + + -- And in this case we might as well use the identifier directly + -- and eliminate the temporary. Note that the analysis of the + -- declaration was not a waste of time in that case, since it is + -- what generated the necessary change of representation code. If + -- the change of representation introduced additional code, as in + -- a fixed-integer conversion, the expression is not an identifier + -- and must be kept. + + if Crep + and then Present (Expression (N_Node)) + and then Is_Entity_Name (Expression (N_Node)) + then + Temp := Entity (Expression (N_Node)); + Rewrite (N_Node, Make_Null_Statement (Loc)); + end if; + + -- For IN parameter, all we do is to replace the actual + + if Ekind (Formal) = E_In_Parameter then + Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); + Analyze (Actual); + + -- Processing for OUT or IN OUT parameter + + else + -- Kill current value indications for the temporary variable we + -- created, since we just passed it as an OUT parameter. + + Kill_Current_Values (Temp); + Set_Is_Known_Valid (Temp, False); + + -- If type conversion, use reverse conversion on exit + + if Nkind (Actual) = N_Type_Conversion then + if Conversion_OK (Actual) then + Expr := OK_Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + else + Expr := Convert_To (V_Typ, New_Occurrence_Of (Temp, Loc)); + end if; + else + Expr := New_Occurrence_Of (Temp, Loc); + end if; + + Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); + Analyze (Actual); + + -- If the actual is a conversion of a packed reference, it may + -- already have been expanded by Remove_Side_Effects, and the + -- resulting variable is a temporary which does not designate + -- the proper out-parameter, which may not be addressable. In + -- that case, generate an assignment to the original expression + -- (before expansion of the packed reference) so that the proper + -- expansion of assignment to a packed component can take place. + + declare + Obj : Node_Id; + Lhs : Node_Id; + + begin + if Is_Renaming_Of_Object (Var) + and then Nkind (Renamed_Object (Var)) = N_Selected_Component + and then Nkind (Original_Node (Prefix (Renamed_Object (Var)))) + = N_Indexed_Component + and then + Has_Non_Standard_Rep (Etype (Prefix (Renamed_Object (Var)))) + then + Obj := Renamed_Object (Var); + Lhs := + Make_Selected_Component (Loc, + Prefix => + New_Copy_Tree (Original_Node (Prefix (Obj))), + Selector_Name => New_Copy (Selector_Name (Obj))); + Reset_Analyzed_Flags (Lhs); + + else + Lhs := New_Occurrence_Of (Var, Loc); + end if; + + Set_Assignment_OK (Lhs); + + if Is_Access_Type (E_Formal) + and then Is_Entity_Name (Lhs) + and then + Present (Effective_Extra_Accessibility (Entity (Lhs))) + then + -- Copyback target is an Ada 2012 stand-alone object of an + -- anonymous access type. + + pragma Assert (Ada_Version >= Ada_2012); + + if Type_Access_Level (E_Formal) > + Object_Access_Level (Lhs) + then + Append_To (Post_Call, + Make_Raise_Program_Error (Loc, + Reason => PE_Accessibility_Check_Failed)); + end if; + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Expr)); + + -- We would like to somehow suppress generation of the + -- extra_accessibility assignment generated by the expansion + -- of the above assignment statement. It's not a correctness + -- issue because the following assignment renders it dead, + -- but generating back-to-back assignments to the same + -- target is undesirable. ??? + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of ( + Effective_Extra_Accessibility (Entity (Lhs)), Loc), + Expression => Make_Integer_Literal (Loc, + Type_Access_Level (E_Formal)))); + + else + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Expr)); + end if; + end; + end if; + end Add_Call_By_Copy_Code; + + ---------------------------------- + -- Add_Simple_Call_By_Copy_Code -- + ---------------------------------- + + procedure Add_Simple_Call_By_Copy_Code is + Decl : Node_Id; + F_Typ : Entity_Id := Etype (Formal); + Incod : Node_Id; + Indic : Node_Id; + Lhs : Node_Id; + Outcod : Node_Id; + Rhs : Node_Id; + Temp : Entity_Id; + + begin + if not Is_Legal_Copy then + return; + end if; + + -- Handle formals whose type comes from the limited view + + if From_Limited_With (F_Typ) + and then Has_Non_Limited_View (F_Typ) + then + F_Typ := Non_Limited_View (F_Typ); + end if; + + -- Use formal type for temp, unless formal type is an unconstrained + -- array, in which case we don't have to worry about bounds checks, + -- and we use the actual type, since that has appropriate bounds. + + if Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + else + Indic := New_Occurrence_Of (F_Typ, Loc); + end if; + + -- Prepare to generate code + + Reset_Packed_Prefix; + + Temp := Make_Temporary (Loc, 'T', Actual); + Incod := Relocate_Node (Actual); + Outcod := New_Copy_Tree (Incod); + + -- Generate declaration of temporary variable, initializing it + -- with the input parameter unless we have an OUT formal or + -- this is an initialization call. + + -- If the formal is an out parameter with discriminants, the + -- discriminants must be captured even if the rest of the object + -- is in principle uninitialized, because the discriminants may + -- be read by the called subprogram. + + if Ekind (Formal) = E_Out_Parameter then + Incod := Empty; + + if Has_Discriminants (F_Typ) then + Indic := New_Occurrence_Of (Etype (Actual), Loc); + end if; + + elsif Inside_Init_Proc then + + -- Could use a comment here to match comment below ??? + + if Nkind (Actual) /= N_Selected_Component + or else + not Has_Discriminant_Dependent_Constraint + (Entity (Selector_Name (Actual))) + then + Incod := Empty; + + -- Otherwise, keep the component in order to generate the proper + -- actual subtype, that depends on enclosing discriminants. + + else + null; + end if; + end if; + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => Indic, + Expression => Incod); + + if Inside_Init_Proc + and then No (Incod) + then + -- If the call is to initialize a component of a composite type, + -- and the component does not depend on discriminants, use the + -- actual type of the component. This is required in case the + -- component is constrained, because in general the formal of the + -- initialization procedure will be unconstrained. Note that if + -- the component being initialized is constrained by an enclosing + -- discriminant, the presence of the initialization in the + -- declaration will generate an expression for the actual subtype. + + Set_No_Initialization (Decl); + Set_Object_Definition (Decl, + New_Occurrence_Of (Etype (Actual), Loc)); + end if; + + Insert_Action (N, Decl); + + -- The actual is simply a reference to the temporary + + Rewrite (Actual, New_Occurrence_Of (Temp, Loc)); + + -- Generate copy out if OUT or IN OUT parameter + + if Ekind (Formal) /= E_In_Parameter then + Lhs := Outcod; + Rhs := New_Occurrence_Of (Temp, Loc); + + -- Deal with conversion + + if Nkind (Lhs) = N_Type_Conversion then + Lhs := Expression (Lhs); + Rhs := Convert_To (Etype (Actual), Rhs); + end if; + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Lhs, + Expression => Rhs)); + Set_Assignment_OK (Name (Last (Post_Call))); + end if; + end Add_Simple_Call_By_Copy_Code; + + -------------------------------------- + -- Add_Validation_Call_By_Copy_Code -- + -------------------------------------- + + procedure Add_Validation_Call_By_Copy_Code (Act : Node_Id) is + Expr : Node_Id; + Obj : Node_Id; + Obj_Typ : Entity_Id; + Var : constant Node_Id := Unqual_Conv (Act); + Var_Id : Entity_Id; + + begin + -- Copy the value of the validation variable back into the object + -- being validated. + + if Is_Entity_Name (Var) then + Var_Id := Entity (Var); + Obj := Validated_Object (Var_Id); + Obj_Typ := Etype (Obj); + + Expr := New_Occurrence_Of (Var_Id, Loc); + + -- A type conversion is needed when the validation variable and + -- the validated object carry different types. This case occurs + -- when the actual is qualified in some fashion. + + -- Common: + -- subtype Int is Integer range ...; + -- procedure Call (Val : in out Integer); + + -- Original: + -- Object : Int; + -- Call (Integer (Object)); + + -- Expanded: + -- Object : Int; + -- Var : Integer := Object; -- conversion to base type + -- if not Var'Valid then -- validity check + -- Call (Var); -- modify Var + -- Object := Int (Var); -- conversion to subtype + + if Etype (Var_Id) /= Obj_Typ then + Expr := + Make_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Obj_Typ, Loc), + Expression => Expr); + end if; + + -- Generate: + -- Object := Var; + -- <or> + -- Object := Object_Type (Var); + + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => Obj, + Expression => Expr)); + + -- If the flow reaches this point, then this routine was invoked with + -- an actual which does not denote a validation variable. + + else + pragma Assert (False); + null; + end if; + end Add_Validation_Call_By_Copy_Code; + + --------------------------- + -- Check_Fortran_Logical -- + --------------------------- + + procedure Check_Fortran_Logical is + Logical : constant Entity_Id := Etype (Formal); + Var : Entity_Id; + + -- Note: this is very incomplete, e.g. it does not handle arrays + -- of logical values. This is really not the right approach at all???) + + begin + if Convention (Subp) = Convention_Fortran + and then Root_Type (Etype (Formal)) = Standard_Boolean + and then Ekind (Formal) /= E_In_Parameter + then + Var := Make_Var (Actual); + Append_To (Post_Call, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Var, Loc), + Expression => + Unchecked_Convert_To ( + Logical, + Make_Op_Ne (Loc, + Left_Opnd => New_Occurrence_Of (Var, Loc), + Right_Opnd => + Unchecked_Convert_To ( + Logical, + New_Occurrence_Of (Standard_False, Loc)))))); + end if; + end Check_Fortran_Logical; + + ------------------- + -- Is_Legal_Copy -- + ------------------- + + function Is_Legal_Copy return Boolean is + begin + -- An attempt to copy a value of such a type can only occur if + -- representation clauses give the actual a misaligned address. + + if Is_By_Reference_Type (Etype (Formal)) then + + -- The actual may in fact be properly aligned but there is not + -- enough front-end information to determine this. In that case + -- gigi will emit an error if a copy is not legal, or generate + -- the proper code. + + return False; + + -- For users of Starlet, we assume that the specification of by- + -- reference mechanism is mandatory. This may lead to unaligned + -- objects but at least for DEC legacy code it is known to work. + -- The warning will alert users of this code that a problem may + -- be lurking. + + elsif Mechanism (Formal) = By_Reference + and then Is_Valued_Procedure (Scope (Formal)) + then + Error_Msg_N + ("by_reference actual may be misaligned??", Actual); + return False; + + else + return True; + end if; + end Is_Legal_Copy; + + -------------- + -- Make_Var -- + -------------- + + function Make_Var (Actual : Node_Id) return Entity_Id is + Var : Entity_Id; + + begin + if Is_Entity_Name (Actual) then + return Entity (Actual); + + else + Var := Make_Temporary (Loc, 'T', Actual); + + N_Node := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Var, + Subtype_Mark => + New_Occurrence_Of (Etype (Actual), Loc), + Name => Relocate_Node (Actual)); + + Insert_Action (N, N_Node); + return Var; + end if; + end Make_Var; + + ------------------------- + -- Reset_Packed_Prefix -- + ------------------------- + + procedure Reset_Packed_Prefix is + Pfx : Node_Id := Actual; + begin + loop + Set_Analyzed (Pfx, False); + exit when + not Nkind_In (Pfx, N_Selected_Component, N_Indexed_Component); + Pfx := Prefix (Pfx); + end loop; + end Reset_Packed_Prefix; + + -- Start of processing for Expand_Actuals + + begin + Post_Call := New_List; + + Formal := First_Formal (Subp); + Actual := First_Actual (N); + while Present (Formal) loop + E_Formal := Etype (Formal); + E_Actual := Etype (Actual); + + -- Handle formals whose type comes from the limited view + + if From_Limited_With (E_Formal) + and then Has_Non_Limited_View (E_Formal) + then + E_Formal := Non_Limited_View (E_Formal); + end if; + + if Is_Scalar_Type (E_Formal) + or else Nkind (Actual) = N_Slice + then + Check_Fortran_Logical; + + -- RM 6.4.1 (11) + + elsif Ekind (Formal) /= E_Out_Parameter then + + -- The unusual case of the current instance of a protected type + -- requires special handling. This can only occur in the context + -- of a call within the body of a protected operation. + + if Is_Entity_Name (Actual) + and then Ekind (Entity (Actual)) = E_Protected_Type + and then In_Open_Scopes (Entity (Actual)) + then + if Scope (Subp) /= Entity (Actual) then + Error_Msg_N + ("operation outside protected type may not " + & "call back its protected operations??", Actual); + end if; + + Rewrite (Actual, + Expand_Protected_Object_Reference (N, Entity (Actual))); + end if; + + -- Ada 2005 (AI-318-02): If the actual parameter is a call to a + -- build-in-place function, then a temporary return object needs + -- to be created and access to it must be passed to the function. + -- Currently we limit such functions to those with inherently + -- limited result subtypes, but eventually we plan to expand the + -- functions that are treated as build-in-place to include other + -- composite result types. + + if Is_Build_In_Place_Function_Call (Actual) then + Make_Build_In_Place_Call_In_Anonymous_Context (Actual); + + -- Ada 2005 (AI-318-02): Specialization of the previous case for + -- actuals containing build-in-place function calls whose returned + -- object covers interface types. + + elsif Present (Unqual_BIP_Iface_Function_Call (Actual)) then + Make_Build_In_Place_Iface_Call_In_Anonymous_Context (Actual); + end if; + + Apply_Constraint_Check (Actual, E_Formal); + + -- Out parameter case. No constraint checks on access type + -- RM 6.4.1 (13) + + elsif Is_Access_Type (E_Formal) then + null; + + -- RM 6.4.1 (14) + + elsif Has_Discriminants (Base_Type (E_Formal)) + or else Has_Non_Null_Base_Init_Proc (E_Formal) + then + Apply_Constraint_Check (Actual, E_Formal); + + -- RM 6.4.1 (15) + + else + Apply_Constraint_Check (Actual, Base_Type (E_Formal)); + end if; + + -- Processing for IN-OUT and OUT parameters + + if Ekind (Formal) /= E_In_Parameter then + + -- For type conversions of arrays, apply length/range checks + + if Is_Array_Type (E_Formal) + and then Nkind (Actual) = N_Type_Conversion + then + if Is_Constrained (E_Formal) then + Apply_Length_Check (Expression (Actual), E_Formal); + else + Apply_Range_Check (Expression (Actual), E_Formal); + end if; + end if; + + -- The actual denotes a variable which captures the value of an + -- object for validation purposes. Add a copy-back to reflect any + -- potential changes in value back into the original object. + + -- Var : ... := Object; + -- if not Var'Valid then -- validity check + -- Call (Var); -- modify var + -- Object := Var; -- update Object + + -- This case is given higher priority because the subsequent check + -- for type conversion may add an extra copy of the variable and + -- prevent proper value propagation back in the original object. + + if Is_Validation_Variable_Reference (Actual) then + Add_Validation_Call_By_Copy_Code (Actual); + + -- If argument is a type conversion for a type that is passed by + -- copy, then we must pass the parameter by copy. + + elsif Nkind (Actual) = N_Type_Conversion + and then + (Is_Numeric_Type (E_Formal) + or else Is_Access_Type (E_Formal) + or else Is_Enumeration_Type (E_Formal) + or else Is_Bit_Packed_Array (Etype (Formal)) + or else Is_Bit_Packed_Array (Etype (Expression (Actual))) + + -- Also pass by copy if change of representation + + or else not Same_Representation + (Etype (Formal), + Etype (Expression (Actual)))) + then + Add_Call_By_Copy_Code; + + -- References to components of bit-packed arrays are expanded + -- at this point, rather than at the point of analysis of the + -- actuals, to handle the expansion of the assignment to + -- [in] out parameters. + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Simple_Call_By_Copy_Code; + + -- If a non-scalar actual is possibly bit-aligned, we need a copy + -- because the back-end cannot cope with such objects. In other + -- cases where alignment forces a copy, the back-end generates + -- it properly. It should not be generated unconditionally in the + -- front-end because it does not know precisely the alignment + -- requirements of the target, and makes too conservative an + -- estimate, leading to superfluous copies or spurious errors + -- on by-reference parameters. + + elsif Nkind (Actual) = N_Selected_Component + and then + Component_May_Be_Bit_Aligned (Entity (Selector_Name (Actual))) + and then not Represented_As_Scalar (Etype (Formal)) + then + Add_Simple_Call_By_Copy_Code; + + -- References to slices of bit-packed arrays are expanded + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- References to possibly unaligned slices of arrays are expanded + + elsif Is_Possibly_Unaligned_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- Deal with access types where the actual subtype and the + -- formal subtype are not the same, requiring a check. + + -- It is necessary to exclude tagged types because of "downward + -- conversion" errors. + + elsif Is_Access_Type (E_Formal) + and then not Same_Type (E_Formal, E_Actual) + and then not Is_Tagged_Type (Designated_Type (E_Formal)) + then + Add_Call_By_Copy_Code; + + -- If the actual is not a scalar and is marked for volatile + -- treatment, whereas the formal is not volatile, then pass + -- by copy unless it is a by-reference type. + + -- Note: we use Is_Volatile here rather than Treat_As_Volatile, + -- because this is the enforcement of a language rule that applies + -- only to "real" volatile variables, not e.g. to the address + -- clause overlay case. + + elsif Is_Entity_Name (Actual) + and then Is_Volatile (Entity (Actual)) + and then not Is_By_Reference_Type (E_Actual) + and then not Is_Scalar_Type (Etype (Entity (Actual))) + and then not Is_Volatile (E_Formal) + then + Add_Call_By_Copy_Code; + + elsif Nkind (Actual) = N_Indexed_Component + and then Is_Entity_Name (Prefix (Actual)) + and then Has_Volatile_Components (Entity (Prefix (Actual))) + then + Add_Call_By_Copy_Code; + + -- Add call-by-copy code for the case of scalar out parameters + -- when it is not known at compile time that the subtype of the + -- formal is a subrange of the subtype of the actual (or vice + -- versa for in out parameters), in order to get range checks + -- on such actuals. (Maybe this case should be handled earlier + -- in the if statement???) + + elsif Is_Scalar_Type (E_Formal) + and then + (not In_Subrange_Of (E_Formal, E_Actual) + or else + (Ekind (Formal) = E_In_Out_Parameter + and then not In_Subrange_Of (E_Actual, E_Formal))) + then + -- Perhaps the setting back to False should be done within + -- Add_Call_By_Copy_Code, since it could get set on other + -- cases occurring above??? + + if Do_Range_Check (Actual) then + Set_Do_Range_Check (Actual, False); + end if; + + Add_Call_By_Copy_Code; + end if; + + -- RM 3.2.4 (23/3): A predicate is checked on in-out and out + -- by-reference parameters on exit from the call. If the actual + -- is a derived type and the operation is inherited, the body + -- of the operation will not contain a call to the predicate + -- function, so it must be done explicitly after the call. Ditto + -- if the actual is an entity of a predicated subtype. + + -- The rule refers to by-reference types, but a check is needed + -- for by-copy types as well. That check is subsumed by the rule + -- for subtype conversion on assignment, but we can generate the + -- required check now. + + -- Note also that Subp may be either a subprogram entity for + -- direct calls, or a type entity for indirect calls, which must + -- be handled separately because the name does not denote an + -- overloadable entity. + + By_Ref_Predicate_Check : declare + Aund : constant Entity_Id := Underlying_Type (E_Actual); + Atyp : Entity_Id; + + function Is_Public_Subp return Boolean; + -- Check whether the subprogram being called is a visible + -- operation of the type of the actual. Used to determine + -- whether an invariant check must be generated on the + -- caller side. + + --------------------- + -- Is_Public_Subp -- + --------------------- + + function Is_Public_Subp return Boolean is + Pack : constant Entity_Id := Scope (Subp); + Subp_Decl : Node_Id; + + begin + if not Is_Subprogram (Subp) then + return False; + + -- The operation may be inherited, or a primitive of the + -- root type. + + elsif + Nkind_In (Parent (Subp), N_Private_Extension_Declaration, + N_Full_Type_Declaration) + then + Subp_Decl := Parent (Subp); + + else + Subp_Decl := Unit_Declaration_Node (Subp); + end if; + + return Ekind (Pack) = E_Package + and then + List_Containing (Subp_Decl) = + Visible_Declarations + (Specification (Unit_Declaration_Node (Pack))); + end Is_Public_Subp; + + -- Start of processing for By_Ref_Predicate_Check + + begin + if No (Aund) then + Atyp := E_Actual; + else + Atyp := Aund; + end if; + + if Has_Predicates (Atyp) + and then Present (Predicate_Function (Atyp)) + + -- Skip predicate checks for special cases + + and then Predicate_Tests_On_Arguments (Subp) + then + Append_To (Post_Call, + Make_Predicate_Check (Atyp, Actual)); + end if; + + -- We generated caller-side invariant checks in two cases: + + -- a) when calling an inherited operation, where there is an + -- implicit view conversion of the actual to the parent type. + + -- b) When the conversion is explicit + + -- We treat these cases separately because the required + -- conversion for a) is added later when expanding the call. + + if Has_Invariants (Etype (Actual)) + and then + Nkind (Parent (Subp)) = N_Private_Extension_Declaration + then + if Comes_From_Source (N) and then Is_Public_Subp then + Append_To (Post_Call, Make_Invariant_Call (Actual)); + end if; + + elsif Nkind (Actual) = N_Type_Conversion + and then Has_Invariants (Etype (Expression (Actual))) + then + if Comes_From_Source (N) and then Is_Public_Subp then + Append_To (Post_Call, + Make_Invariant_Call (Expression (Actual))); + end if; + end if; + end By_Ref_Predicate_Check; + + -- Processing for IN parameters + + else + -- For IN parameters in the bit-packed array case, we expand an + -- indexed component (the circuit in Exp_Ch4 deliberately left + -- indexed components appearing as actuals untouched, so that + -- the special processing above for the OUT and IN OUT cases + -- could be performed. We could make the test in Exp_Ch4 more + -- complex and have it detect the parameter mode, but it is + -- easier simply to handle all cases here.) + + if Nkind (Actual) = N_Indexed_Component + and then Is_Bit_Packed_Array (Etype (Prefix (Actual))) + then + Reset_Packed_Prefix; + Expand_Packed_Element_Reference (Actual); + + -- If we have a reference to a bit-packed array, we copy it, since + -- the actual must be byte aligned. + + -- Is this really necessary in all cases??? + + elsif Is_Ref_To_Bit_Packed_Array (Actual) then + Add_Simple_Call_By_Copy_Code; + + -- If a non-scalar actual is possibly unaligned, we need a copy + + elsif Is_Possibly_Unaligned_Object (Actual) + and then not Represented_As_Scalar (Etype (Formal)) + then + Add_Simple_Call_By_Copy_Code; + + -- Similarly, we have to expand slices of packed arrays here + -- because the result must be byte aligned. + + elsif Is_Ref_To_Bit_Packed_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- Only processing remaining is to pass by copy if this is a + -- reference to a possibly unaligned slice, since the caller + -- expects an appropriately aligned argument. + + elsif Is_Possibly_Unaligned_Slice (Actual) then + Add_Call_By_Copy_Code; + + -- An unusual case: a current instance of an enclosing task can be + -- an actual, and must be replaced by a reference to self. + + elsif Is_Entity_Name (Actual) + and then Is_Task_Type (Entity (Actual)) + then + if In_Open_Scopes (Entity (Actual)) then + Rewrite (Actual, + (Make_Function_Call (Loc, + Name => New_Occurrence_Of (RTE (RE_Self), Loc)))); + Analyze (Actual); + + -- A task type cannot otherwise appear as an actual + + else + raise Program_Error; + end if; + end if; + end if; + + Next_Formal (Formal); + Next_Actual (Actual); + end loop; + end Expand_Actuals; + + ----------------- + -- Expand_Call -- + ----------------- + + procedure Expand_Call (N : Node_Id) is + Post_Call : List_Id; + + begin + pragma Assert (Nkind_In (N, N_Entry_Call_Statement, + N_Function_Call, + N_Procedure_Call_Statement)); + + Expand_Call_Helper (N, Post_Call); + Insert_Post_Call_Actions (N, Post_Call); + end Expand_Call; + + ------------------------ + -- Expand_Call_Helper -- + ------------------------ + + -- This procedure handles expansion of function calls and procedure call + -- statements (i.e. it serves as the body for Expand_N_Function_Call and + -- Expand_N_Procedure_Call_Statement). Processing for calls includes: + + -- Replace call to Raise_Exception by Raise_Exception_Always if possible + -- Provide values of actuals for all formals in Extra_Formals list + -- Replace "call" to enumeration literal function by literal itself + -- Rewrite call to predefined operator as operator + -- Replace actuals to in-out parameters that are numeric conversions, + -- with explicit assignment to temporaries before and after the call. + + -- Note that the list of actuals has been filled with default expressions + -- during semantic analysis of the call. Only the extra actuals required + -- for the 'Constrained attribute and for accessibility checks are added + -- at this point. + + procedure Expand_Call_Helper (N : Node_Id; Post_Call : out List_Id) is + Loc : constant Source_Ptr := Sloc (N); + Call_Node : Node_Id := N; + Extra_Actuals : List_Id := No_List; + Prev : Node_Id := Empty; + + procedure Add_Actual_Parameter (Insert_Param : Node_Id); + -- Adds one entry to the end of the actual parameter list. Used for + -- default parameters and for extra actuals (for Extra_Formals). The + -- argument is an N_Parameter_Association node. + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id); + -- Adds an extra actual to the list of extra actuals. Expr is the + -- expression for the value of the actual, EF is the entity for the + -- extra formal. + + procedure Add_View_Conversion_Invariants + (Formal : Entity_Id; + Actual : Node_Id); + -- Adds invariant checks for every intermediate type between the range + -- of a view converted argument to its ancestor (from parent to child). + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id; + -- Within an instance, a type derived from an untagged formal derived + -- type inherits from the original parent, not from the actual. The + -- current derivation mechanism has the derived type inherit from the + -- actual, which is only correct outside of the instance. If the + -- subprogram is inherited, we test for this particular case through a + -- convoluted tree traversal before setting the proper subprogram to be + -- called. + + function In_Unfrozen_Instance (E : Entity_Id) return Boolean; + -- Return true if E comes from an instance that is not yet frozen + + function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean; + -- Determine if Subp denotes a non-dispatching call to a Deep routine + + function New_Value (From : Node_Id) return Node_Id; + -- From is the original Expression. New_Value is equivalent to a call + -- to Duplicate_Subexpr with an explicit dereference when From is an + -- access parameter. + + -------------------------- + -- Add_Actual_Parameter -- + -------------------------- + + procedure Add_Actual_Parameter (Insert_Param : Node_Id) is + Actual_Expr : constant Node_Id := + Explicit_Actual_Parameter (Insert_Param); + + begin + -- Case of insertion is first named actual + + if No (Prev) or else + Nkind (Parent (Prev)) /= N_Parameter_Association + then + Set_Next_Named_Actual + (Insert_Param, First_Named_Actual (Call_Node)); + Set_First_Named_Actual (Call_Node, Actual_Expr); + + if No (Prev) then + if No (Parameter_Associations (Call_Node)) then + Set_Parameter_Associations (Call_Node, New_List); + end if; + + Append (Insert_Param, Parameter_Associations (Call_Node)); + + else + Insert_After (Prev, Insert_Param); + end if; + + -- Case of insertion is not first named actual + + else + Set_Next_Named_Actual + (Insert_Param, Next_Named_Actual (Parent (Prev))); + Set_Next_Named_Actual (Parent (Prev), Actual_Expr); + Append (Insert_Param, Parameter_Associations (Call_Node)); + end if; + + Prev := Actual_Expr; + end Add_Actual_Parameter; + + ---------------------- + -- Add_Extra_Actual -- + ---------------------- + + procedure Add_Extra_Actual (Expr : Node_Id; EF : Entity_Id) is + Loc : constant Source_Ptr := Sloc (Expr); + + begin + if Extra_Actuals = No_List then + Extra_Actuals := New_List; + Set_Parent (Extra_Actuals, Call_Node); + end if; + + Append_To (Extra_Actuals, + Make_Parameter_Association (Loc, + Selector_Name => New_Occurrence_Of (EF, Loc), + Explicit_Actual_Parameter => Expr)); + + Analyze_And_Resolve (Expr, Etype (EF)); + + if Nkind (Call_Node) = N_Function_Call then + Set_Is_Accessibility_Actual (Parent (Expr)); + end if; + end Add_Extra_Actual; + + ------------------------------------ + -- Add_View_Conversion_Invariants -- + ------------------------------------ + + procedure Add_View_Conversion_Invariants + (Formal : Entity_Id; + Actual : Node_Id) + is + Arg : Entity_Id; + Curr_Typ : Entity_Id; + Inv_Checks : List_Id; + Par_Typ : Entity_Id; + + begin + Inv_Checks := No_List; + + -- Extract the argument from a potentially nested set of view + -- conversions. + + Arg := Actual; + while Nkind (Arg) = N_Type_Conversion loop + Arg := Expression (Arg); + end loop; + + -- Move up the derivation chain starting with the type of the formal + -- parameter down to the type of the actual object. + + Curr_Typ := Empty; + Par_Typ := Etype (Arg); + while Par_Typ /= Etype (Formal) and Par_Typ /= Curr_Typ loop + Curr_Typ := Par_Typ; + + if Has_Invariants (Curr_Typ) + and then Present (Invariant_Procedure (Curr_Typ)) + then + -- Verify the invariate of the current type. Generate: + + -- <Curr_Typ>Invariant (Curr_Typ (Arg)); + + Prepend_New_To (Inv_Checks, + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of + (Invariant_Procedure (Curr_Typ), Loc), + Parameter_Associations => New_List ( + Make_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Curr_Typ, Loc), + Expression => New_Copy_Tree (Arg))))); + end if; + + Par_Typ := Base_Type (Etype (Curr_Typ)); + end loop; + + if not Is_Empty_List (Inv_Checks) then + Insert_Actions_After (N, Inv_Checks); + end if; + end Add_View_Conversion_Invariants; + + --------------------------- + -- Inherited_From_Formal -- + --------------------------- + + function Inherited_From_Formal (S : Entity_Id) return Entity_Id is + Par : Entity_Id; + Gen_Par : Entity_Id; + Gen_Prim : Elist_Id; + Elmt : Elmt_Id; + Indic : Node_Id; + + begin + -- If the operation is inherited, it is attached to the corresponding + -- type derivation. If the parent in the derivation is a generic + -- actual, it is a subtype of the actual, and we have to recover the + -- original derived type declaration to find the proper parent. + + if Nkind (Parent (S)) /= N_Full_Type_Declaration + or else not Is_Derived_Type (Defining_Identifier (Parent (S))) + or else Nkind (Type_Definition (Original_Node (Parent (S)))) /= + N_Derived_Type_Definition + or else not In_Instance + then + return Empty; + + else + Indic := + Subtype_Indication + (Type_Definition (Original_Node (Parent (S)))); + + if Nkind (Indic) = N_Subtype_Indication then + Par := Entity (Subtype_Mark (Indic)); + else + Par := Entity (Indic); + end if; + end if; + + if not Is_Generic_Actual_Type (Par) + or else Is_Tagged_Type (Par) + or else Nkind (Parent (Par)) /= N_Subtype_Declaration + or else not In_Open_Scopes (Scope (Par)) + then + return Empty; + else + Gen_Par := Generic_Parent_Type (Parent (Par)); + end if; + + -- If the actual has no generic parent type, the formal is not + -- a formal derived type, so nothing to inherit. + + if No (Gen_Par) then + return Empty; + end if; + + -- If the generic parent type is still the generic type, this is a + -- private formal, not a derived formal, and there are no operations + -- inherited from the formal. + + if Nkind (Parent (Gen_Par)) = N_Formal_Type_Declaration then + return Empty; + end if; + + Gen_Prim := Collect_Primitive_Operations (Gen_Par); + + Elmt := First_Elmt (Gen_Prim); + while Present (Elmt) loop + if Chars (Node (Elmt)) = Chars (S) then + declare + F1 : Entity_Id; + F2 : Entity_Id; + + begin + F1 := First_Formal (S); + F2 := First_Formal (Node (Elmt)); + while Present (F1) + and then Present (F2) + loop + if Etype (F1) = Etype (F2) + or else Etype (F2) = Gen_Par + then + Next_Formal (F1); + Next_Formal (F2); + else + Next_Elmt (Elmt); + exit; -- not the right subprogram + end if; + + return Node (Elmt); + end loop; + end; + + else + Next_Elmt (Elmt); + end if; + end loop; + + raise Program_Error; + end Inherited_From_Formal; + + -------------------------- + -- In_Unfrozen_Instance -- + -------------------------- + + function In_Unfrozen_Instance (E : Entity_Id) return Boolean is + S : Entity_Id; + + begin + S := E; + while Present (S) and then S /= Standard_Standard loop + if Is_Generic_Instance (S) + and then Present (Freeze_Node (S)) + and then not Analyzed (Freeze_Node (S)) + then + return True; + end if; + + S := Scope (S); + end loop; + + return False; + end In_Unfrozen_Instance; + + ------------------------- + -- Is_Direct_Deep_Call -- + ------------------------- + + function Is_Direct_Deep_Call (Subp : Entity_Id) return Boolean is + begin + if Is_TSS (Subp, TSS_Deep_Adjust) + or else Is_TSS (Subp, TSS_Deep_Finalize) + or else Is_TSS (Subp, TSS_Deep_Initialize) + then + declare + Actual : Node_Id; + Formal : Node_Id; + + begin + Actual := First (Parameter_Associations (N)); + Formal := First_Formal (Subp); + while Present (Actual) + and then Present (Formal) + loop + if Nkind (Actual) = N_Identifier + and then Is_Controlling_Actual (Actual) + and then Etype (Actual) = Etype (Formal) + then + return True; + end if; + + Next (Actual); + Next_Formal (Formal); + end loop; + end; + end if; + + return False; + end Is_Direct_Deep_Call; + + --------------- + -- New_Value -- + --------------- + + function New_Value (From : Node_Id) return Node_Id is + Res : constant Node_Id := Duplicate_Subexpr (From); + begin + if Is_Access_Type (Etype (From)) then + return Make_Explicit_Dereference (Sloc (From), Prefix => Res); + else + return Res; + end if; + end New_Value; + + -- Local variables + + Remote : constant Boolean := Is_Remote_Call (Call_Node); + Actual : Node_Id; + Formal : Entity_Id; + Orig_Subp : Entity_Id := Empty; + Param_Count : Natural := 0; + Parent_Formal : Entity_Id; + Parent_Subp : Entity_Id; + Pref_Entity : Entity_Id; + Scop : Entity_Id; + Subp : Entity_Id; + + Prev_Orig : Node_Id; + -- Original node for an actual, which may have been rewritten. If the + -- actual is a function call that has been transformed from a selected + -- component, the original node is unanalyzed. Otherwise, it carries + -- semantic information used to generate additional actuals. + + CW_Interface_Formals_Present : Boolean := False; + + -- Start of processing for Expand_Call_Helper + + begin + Post_Call := New_List; + + -- Expand the function or procedure call if the first actual has a + -- declared dimension aspect, and the subprogram is declared in one + -- of the dimension I/O packages. + + if Ada_Version >= Ada_2012 + and then + Nkind_In (Call_Node, N_Procedure_Call_Statement, N_Function_Call) + and then Present (Parameter_Associations (Call_Node)) + then + Expand_Put_Call_With_Symbol (Call_Node); + end if; + + -- Ignore if previous error + + if Nkind (Call_Node) in N_Has_Etype + and then Etype (Call_Node) = Any_Type + then + return; + end if; + + -- Call using access to subprogram with explicit dereference + + if Nkind (Name (Call_Node)) = N_Explicit_Dereference then + Subp := Etype (Name (Call_Node)); + Parent_Subp := Empty; + + -- Case of call to simple entry, where the Name is a selected component + -- whose prefix is the task, and whose selector name is the entry name + + elsif Nkind (Name (Call_Node)) = N_Selected_Component then + Subp := Entity (Selector_Name (Name (Call_Node))); + Parent_Subp := Empty; + + -- Case of call to member of entry family, where Name is an indexed + -- component, with the prefix being a selected component giving the + -- task and entry family name, and the index being the entry index. + + elsif Nkind (Name (Call_Node)) = N_Indexed_Component then + Subp := Entity (Selector_Name (Prefix (Name (Call_Node)))); + Parent_Subp := Empty; + + -- Normal case + + else + Subp := Entity (Name (Call_Node)); + Parent_Subp := Alias (Subp); + + -- Replace call to Raise_Exception by call to Raise_Exception_Always + -- if we can tell that the first parameter cannot possibly be null. + -- This improves efficiency by avoiding a run-time test. + + -- We do not do this if Raise_Exception_Always does not exist, which + -- can happen in configurable run time profiles which provide only a + -- Raise_Exception. + + if Is_RTE (Subp, RE_Raise_Exception) + and then RTE_Available (RE_Raise_Exception_Always) + then + declare + FA : constant Node_Id := + Original_Node (First_Actual (Call_Node)); + + begin + -- The case we catch is where the first argument is obtained + -- using the Identity attribute (which must always be + -- non-null). + + if Nkind (FA) = N_Attribute_Reference + and then Attribute_Name (FA) = Name_Identity + then + Subp := RTE (RE_Raise_Exception_Always); + Set_Name (Call_Node, New_Occurrence_Of (Subp, Loc)); + end if; + end; + end if; + + if Ekind (Subp) = E_Entry then + Parent_Subp := Empty; + end if; + end if; + + -- Ada 2005 (AI-345): We have a procedure call as a triggering + -- alternative in an asynchronous select or as an entry call in + -- a conditional or timed select. Check whether the procedure call + -- is a renaming of an entry and rewrite it as an entry call. + + if Ada_Version >= Ada_2005 + and then Nkind (Call_Node) = N_Procedure_Call_Statement + and then + ((Nkind (Parent (Call_Node)) = N_Triggering_Alternative + and then Triggering_Statement (Parent (Call_Node)) = Call_Node) + or else + (Nkind (Parent (Call_Node)) = N_Entry_Call_Alternative + and then Entry_Call_Statement (Parent (Call_Node)) = Call_Node)) + then + declare + Ren_Decl : Node_Id; + Ren_Root : Entity_Id := Subp; + + begin + -- This may be a chain of renamings, find the root + + if Present (Alias (Ren_Root)) then + Ren_Root := Alias (Ren_Root); + end if; + + if Present (Original_Node (Parent (Parent (Ren_Root)))) then + Ren_Decl := Original_Node (Parent (Parent (Ren_Root))); + + if Nkind (Ren_Decl) = N_Subprogram_Renaming_Declaration then + Rewrite (Call_Node, + Make_Entry_Call_Statement (Loc, + Name => + New_Copy_Tree (Name (Ren_Decl)), + Parameter_Associations => + New_Copy_List_Tree + (Parameter_Associations (Call_Node)))); + + return; + end if; + end if; + end; + end if; + + if Modify_Tree_For_C + and then Nkind (Call_Node) = N_Function_Call + and then Is_Entity_Name (Name (Call_Node)) + then + declare + Func_Id : constant Entity_Id := + Ultimate_Alias (Entity (Name (Call_Node))); + begin + -- When generating C code, transform a function call that returns + -- a constrained array type into procedure form. + + if Rewritten_For_C (Func_Id) then + + -- For internally generated calls ensure that they reference + -- the entity of the spec of the called function (needed since + -- the expander may generate calls using the entity of their + -- body). See for example Expand_Boolean_Operator(). + + if not (Comes_From_Source (Call_Node)) + and then Nkind (Unit_Declaration_Node (Func_Id)) = + N_Subprogram_Body + then + Set_Entity (Name (Call_Node), + Corresponding_Function + (Corresponding_Procedure (Func_Id))); + end if; + + Rewrite_Function_Call_For_C (Call_Node); + return; + + -- Also introduce a temporary for functions that return a record + -- called within another procedure or function call, since records + -- are passed by pointer in the generated C code, and we cannot + -- take a pointer from a subprogram call. + + elsif Nkind (Parent (Call_Node)) in N_Subprogram_Call + and then Is_Record_Type (Etype (Func_Id)) + then + declare + Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); + Decl : Node_Id; + + begin + -- Generate: + -- Temp : ... := Func_Call (...); + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp_Id, + Object_Definition => + New_Occurrence_Of (Etype (Func_Id), Loc), + Expression => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (Func_Id, Loc), + Parameter_Associations => + Parameter_Associations (Call_Node))); + + Insert_Action (Parent (Call_Node), Decl); + Rewrite (Call_Node, New_Occurrence_Of (Temp_Id, Loc)); + return; + end; + end if; + end; + end if; + + -- First step, compute extra actuals, corresponding to any Extra_Formals + -- present. Note that we do not access Extra_Formals directly, instead + -- we simply note the presence of the extra formals as we process the + -- regular formals collecting corresponding actuals in Extra_Actuals. + + -- We also generate any required range checks for actuals for in formals + -- as we go through the loop, since this is a convenient place to do it. + -- (Though it seems that this would be better done in Expand_Actuals???) + + -- Special case: Thunks must not compute the extra actuals; they must + -- just propagate to the target primitive their extra actuals. + + if Is_Thunk (Current_Scope) + and then Thunk_Entity (Current_Scope) = Subp + and then Present (Extra_Formals (Subp)) + then + pragma Assert (Present (Extra_Formals (Current_Scope))); + + declare + Target_Formal : Entity_Id; + Thunk_Formal : Entity_Id; + + begin + Target_Formal := Extra_Formals (Subp); + Thunk_Formal := Extra_Formals (Current_Scope); + while Present (Target_Formal) loop + Add_Extra_Actual + (Expr => New_Occurrence_Of (Thunk_Formal, Loc), + EF => Thunk_Formal); + + Target_Formal := Extra_Formal (Target_Formal); + Thunk_Formal := Extra_Formal (Thunk_Formal); + end loop; + + while Is_Non_Empty_List (Extra_Actuals) loop + Add_Actual_Parameter (Remove_Head (Extra_Actuals)); + end loop; + + Expand_Actuals (Call_Node, Subp, Post_Call); + pragma Assert (Is_Empty_List (Post_Call)); + return; + end; + end if; + + Formal := First_Formal (Subp); + Actual := First_Actual (Call_Node); + Param_Count := 1; + while Present (Formal) loop + + -- Generate range check if required + + if Do_Range_Check (Actual) + and then Ekind (Formal) = E_In_Parameter + then + Generate_Range_Check + (Actual, Etype (Formal), CE_Range_Check_Failed); + end if; + + -- Prepare to examine current entry + + Prev := Actual; + Prev_Orig := Original_Node (Prev); + + -- Ada 2005 (AI-251): Check if any formal is a class-wide interface + -- to expand it in a further round. + + CW_Interface_Formals_Present := + CW_Interface_Formals_Present + or else + (Is_Class_Wide_Type (Etype (Formal)) + and then Is_Interface (Etype (Etype (Formal)))) + or else + (Ekind (Etype (Formal)) = E_Anonymous_Access_Type + and then Is_Class_Wide_Type (Directly_Designated_Type + (Etype (Etype (Formal)))) + and then Is_Interface (Directly_Designated_Type + (Etype (Etype (Formal))))); + + -- Create possible extra actual for constrained case. Usually, the + -- extra actual is of the form actual'constrained, but since this + -- attribute is only available for unconstrained records, TRUE is + -- expanded if the type of the formal happens to be constrained (for + -- instance when this procedure is inherited from an unconstrained + -- record to a constrained one) or if the actual has no discriminant + -- (its type is constrained). An exception to this is the case of a + -- private type without discriminants. In this case we pass FALSE + -- because the object has underlying discriminants with defaults. + + if Present (Extra_Constrained (Formal)) then + if Ekind (Etype (Prev)) in Private_Kind + and then not Has_Discriminants (Base_Type (Etype (Prev))) + then + Add_Extra_Actual + (Expr => New_Occurrence_Of (Standard_False, Loc), + EF => Extra_Constrained (Formal)); + + elsif Is_Constrained (Etype (Formal)) + or else not Has_Discriminants (Etype (Prev)) + then + Add_Extra_Actual + (Expr => New_Occurrence_Of (Standard_True, Loc), + EF => Extra_Constrained (Formal)); + + -- Do not produce extra actuals for Unchecked_Union parameters. + -- Jump directly to the end of the loop. + + elsif Is_Unchecked_Union (Base_Type (Etype (Actual))) then + goto Skip_Extra_Actual_Generation; + + else + -- If the actual is a type conversion, then the constrained + -- test applies to the actual, not the target type. + + declare + Act_Prev : Node_Id; + + begin + -- Test for unchecked conversions as well, which can occur + -- as out parameter actuals on calls to stream procedures. + + Act_Prev := Prev; + while Nkind_In (Act_Prev, N_Type_Conversion, + N_Unchecked_Type_Conversion) + loop + Act_Prev := Expression (Act_Prev); + end loop; + + -- If the expression is a conversion of a dereference, this + -- is internally generated code that manipulates addresses, + -- e.g. when building interface tables. No check should + -- occur in this case, and the discriminated object is not + -- directly a hand. + + if not Comes_From_Source (Actual) + and then Nkind (Actual) = N_Unchecked_Type_Conversion + and then Nkind (Act_Prev) = N_Explicit_Dereference + then + Add_Extra_Actual + (Expr => New_Occurrence_Of (Standard_False, Loc), + EF => Extra_Constrained (Formal)); + + else + Add_Extra_Actual + (Expr => + Make_Attribute_Reference (Sloc (Prev), + Prefix => + Duplicate_Subexpr_No_Checks + (Act_Prev, Name_Req => True), + Attribute_Name => Name_Constrained), + EF => Extra_Constrained (Formal)); + end if; + end; + end if; + end if; + + -- Create possible extra actual for accessibility level + + if Present (Extra_Accessibility (Formal)) then + + -- Ada 2005 (AI-252): If the actual was rewritten as an Access + -- attribute, then the original actual may be an aliased object + -- occurring as the prefix in a call using "Object.Operation" + -- notation. In that case we must pass the level of the object, + -- so Prev_Orig is reset to Prev and the attribute will be + -- processed by the code for Access attributes further below. + + if Prev_Orig /= Prev + and then Nkind (Prev) = N_Attribute_Reference + and then Get_Attribute_Id (Attribute_Name (Prev)) = + Attribute_Access + and then Is_Aliased_View (Prev_Orig) + then + Prev_Orig := Prev; + + -- A class-wide precondition generates a test in which formals of + -- the subprogram are replaced by actuals that came from source. + -- In that case as well, the accessiblity comes from the actual. + -- This is the one case in which there are references to formals + -- outside of their subprogram. + + elsif Prev_Orig /= Prev + and then Is_Entity_Name (Prev_Orig) + and then Present (Entity (Prev_Orig)) + and then Is_Formal (Entity (Prev_Orig)) + and then not In_Open_Scopes (Scope (Entity (Prev_Orig))) + then + Prev_Orig := Prev; + + -- If the actual is a formal of an enclosing subprogram it is + -- the right entity, even if it is a rewriting. This happens + -- when the call is within an inherited condition or predicate. + + elsif Is_Entity_Name (Actual) + and then Is_Formal (Entity (Actual)) + and then In_Open_Scopes (Scope (Entity (Actual))) + then + Prev_Orig := Prev; + + elsif Nkind (Prev_Orig) = N_Type_Conversion then + Prev_Orig := Expression (Prev_Orig); + end if; + + -- Ada 2005 (AI-251): Thunks must propagate the extra actuals of + -- accessibility levels. + + if Is_Thunk (Current_Scope) then + declare + Parm_Ent : Entity_Id; + + begin + if Is_Controlling_Actual (Actual) then + + -- Find the corresponding actual of the thunk + + Parm_Ent := First_Entity (Current_Scope); + for J in 2 .. Param_Count loop + Next_Entity (Parm_Ent); + end loop; + + -- Handle unchecked conversion of access types generated + -- in thunks (cf. Expand_Interface_Thunk). + + elsif Is_Access_Type (Etype (Actual)) + and then Nkind (Actual) = N_Unchecked_Type_Conversion + then + Parm_Ent := Entity (Expression (Actual)); + + else pragma Assert (Is_Entity_Name (Actual)); + Parm_Ent := Entity (Actual); + end if; + + Add_Extra_Actual + (Expr => + New_Occurrence_Of (Extra_Accessibility (Parm_Ent), Loc), + EF => Extra_Accessibility (Formal)); + end; + + elsif Is_Entity_Name (Prev_Orig) then + + -- When passing an access parameter, or a renaming of an access + -- parameter, as the actual to another access parameter we need + -- to pass along the actual's own access level parameter. This + -- is done if we are within the scope of the formal access + -- parameter (if this is an inlined body the extra formal is + -- irrelevant). + + if (Is_Formal (Entity (Prev_Orig)) + or else + (Present (Renamed_Object (Entity (Prev_Orig))) + and then + Is_Entity_Name (Renamed_Object (Entity (Prev_Orig))) + and then + Is_Formal + (Entity (Renamed_Object (Entity (Prev_Orig)))))) + and then Ekind (Etype (Prev_Orig)) = E_Anonymous_Access_Type + and then In_Open_Scopes (Scope (Entity (Prev_Orig))) + then + declare + Parm_Ent : constant Entity_Id := Param_Entity (Prev_Orig); + + begin + pragma Assert (Present (Parm_Ent)); + + if Present (Extra_Accessibility (Parm_Ent)) then + Add_Extra_Actual + (Expr => + New_Occurrence_Of + (Extra_Accessibility (Parm_Ent), Loc), + EF => Extra_Accessibility (Formal)); + + -- If the actual access parameter does not have an + -- associated extra formal providing its scope level, + -- then treat the actual as having library-level + -- accessibility. + + else + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + EF => Extra_Accessibility (Formal)); + end if; + end; + + -- The actual is a normal access value, so just pass the level + -- of the actual's access type. + + else + Add_Extra_Actual + (Expr => Dynamic_Accessibility_Level (Prev_Orig), + EF => Extra_Accessibility (Formal)); + end if; + + -- If the actual is an access discriminant, then pass the level + -- of the enclosing object (RM05-3.10.2(12.4/2)). + + elsif Nkind (Prev_Orig) = N_Selected_Component + and then Ekind (Entity (Selector_Name (Prev_Orig))) = + E_Discriminant + and then Ekind (Etype (Entity (Selector_Name (Prev_Orig)))) = + E_Anonymous_Access_Type + then + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => Object_Access_Level (Prefix (Prev_Orig))), + EF => Extra_Accessibility (Formal)); + + -- All other cases + + else + case Nkind (Prev_Orig) is + when N_Attribute_Reference => + case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is + + -- For X'Access, pass on the level of the prefix X + + when Attribute_Access => + + -- Accessibility level of S'Access is that of A + + Prev_Orig := Prefix (Prev_Orig); + + -- If the expression is a view conversion, the + -- accessibility level is that of the expression. + + if Nkind (Original_Node (Prev_Orig)) = + N_Type_Conversion + and then + Nkind (Expression (Original_Node (Prev_Orig))) = + N_Explicit_Dereference + then + Prev_Orig := + Expression (Original_Node (Prev_Orig)); + end if; + + -- If this is an Access attribute applied to the + -- the current instance object passed to a type + -- initialization procedure, then use the level + -- of the type itself. This is not really correct, + -- as there should be an extra level parameter + -- passed in with _init formals (only in the case + -- where the type is immutably limited), but we + -- don't have an easy way currently to create such + -- an extra formal (init procs aren't ever frozen). + -- For now we just use the level of the type, + -- which may be too shallow, but that works better + -- than passing Object_Access_Level of the type, + -- which can be one level too deep in some cases. + -- ??? + + -- A further case that requires special handling + -- is the common idiom E.all'access. If E is a + -- formal of the enclosing subprogram, the + -- accessibility of the expression is that of E. + + if Is_Entity_Name (Prev_Orig) then + Pref_Entity := Entity (Prev_Orig); + + elsif Nkind (Prev_Orig) = N_Explicit_Dereference + and then Is_Entity_Name (Prefix (Prev_Orig)) + then + Pref_Entity := Entity (Prefix ((Prev_Orig))); + + else + Pref_Entity := Empty; + end if; + + if Is_Entity_Name (Prev_Orig) + and then Is_Type (Entity (Prev_Orig)) + then + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => + Type_Access_Level (Pref_Entity)), + EF => Extra_Accessibility (Formal)); + + elsif Nkind (Prev_Orig) = N_Explicit_Dereference + and then Present (Pref_Entity) + and then Is_Formal (Pref_Entity) + and then Present + (Extra_Accessibility (Pref_Entity)) + then + Add_Extra_Actual + (Expr => + New_Occurrence_Of + (Extra_Accessibility (Pref_Entity), Loc), + EF => Extra_Accessibility (Formal)); + + else + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => + Object_Access_Level (Prev_Orig)), + EF => Extra_Accessibility (Formal)); + end if; + + -- Treat the unchecked attributes as library-level + + when Attribute_Unchecked_Access + | Attribute_Unrestricted_Access + => + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Standard_Standard)), + EF => Extra_Accessibility (Formal)); + + -- No other cases of attributes returning access + -- values that can be passed to access parameters. + + when others => + raise Program_Error; + + end case; + + -- For allocators we pass the level of the execution of the + -- called subprogram, which is one greater than the current + -- scope level. + + when N_Allocator => + Add_Extra_Actual + (Expr => + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Current_Scope) + 1), + EF => Extra_Accessibility (Formal)); + + -- For most other cases we simply pass the level of the + -- actual's access type. The type is retrieved from + -- Prev rather than Prev_Orig, because in some cases + -- Prev_Orig denotes an original expression that has + -- not been analyzed. + + when others => + Add_Extra_Actual + (Expr => Dynamic_Accessibility_Level (Prev), + EF => Extra_Accessibility (Formal)); + end case; + end if; + end if; + + -- Perform the check of 4.6(49) that prevents a null value from being + -- passed as an actual to an access parameter. Note that the check + -- is elided in the common cases of passing an access attribute or + -- access parameter as an actual. Also, we currently don't enforce + -- this check for expander-generated actuals and when -gnatdj is set. + + if Ada_Version >= Ada_2005 then + + -- Ada 2005 (AI-231): Check null-excluding access types. Note that + -- the intent of 6.4.1(13) is that null-exclusion checks should + -- not be done for 'out' parameters, even though it refers only + -- to constraint checks, and a null_exclusion is not a constraint. + -- Note that AI05-0196-1 corrects this mistake in the RM. + + if Is_Access_Type (Etype (Formal)) + and then Can_Never_Be_Null (Etype (Formal)) + and then Ekind (Formal) /= E_Out_Parameter + and then Nkind (Prev) /= N_Raise_Constraint_Error + and then (Known_Null (Prev) + or else not Can_Never_Be_Null (Etype (Prev))) + then + Install_Null_Excluding_Check (Prev); + end if; + + -- Ada_Version < Ada_2005 + + else + if Ekind (Etype (Formal)) /= E_Anonymous_Access_Type + or else Access_Checks_Suppressed (Subp) + then + null; + + elsif Debug_Flag_J then + null; + + elsif not Comes_From_Source (Prev) then + null; + + elsif Is_Entity_Name (Prev) + and then Ekind (Etype (Prev)) = E_Anonymous_Access_Type + then + null; + + elsif Nkind_In (Prev, N_Allocator, N_Attribute_Reference) then + null; + + else + Install_Null_Excluding_Check (Prev); + end if; + end if; + + -- Perform appropriate validity checks on parameters that + -- are entities. + + if Validity_Checks_On then + if (Ekind (Formal) = E_In_Parameter + and then Validity_Check_In_Params) + or else + (Ekind (Formal) = E_In_Out_Parameter + and then Validity_Check_In_Out_Params) + then + -- If the actual is an indexed component of a packed type (or + -- is an indexed or selected component whose prefix recursively + -- meets this condition), it has not been expanded yet. It will + -- be copied in the validity code that follows, and has to be + -- expanded appropriately, so reanalyze it. + + -- What we do is just to unset analyzed bits on prefixes till + -- we reach something that does not have a prefix. + + declare + Nod : Node_Id; + + begin + Nod := Actual; + while Nkind_In (Nod, N_Indexed_Component, + N_Selected_Component) + loop + Set_Analyzed (Nod, False); + Nod := Prefix (Nod); + end loop; + end; + + Ensure_Valid (Actual); + end if; + end if; + + -- For IN OUT and OUT parameters, ensure that subscripts are valid + -- since this is a left side reference. We only do this for calls + -- from the source program since we assume that compiler generated + -- calls explicitly generate any required checks. We also need it + -- only if we are doing standard validity checks, since clearly it is + -- not needed if validity checks are off, and in subscript validity + -- checking mode, all indexed components are checked with a call + -- directly from Expand_N_Indexed_Component. + + if Comes_From_Source (Call_Node) + and then Ekind (Formal) /= E_In_Parameter + and then Validity_Checks_On + and then Validity_Check_Default + and then not Validity_Check_Subscripts + then + Check_Valid_Lvalue_Subscripts (Actual); + end if; + + -- Mark any scalar OUT parameter that is a simple variable as no + -- longer known to be valid (unless the type is always valid). This + -- reflects the fact that if an OUT parameter is never set in a + -- procedure, then it can become invalid on the procedure return. + + if Ekind (Formal) = E_Out_Parameter + and then Is_Entity_Name (Actual) + and then Ekind (Entity (Actual)) = E_Variable + and then not Is_Known_Valid (Etype (Actual)) + then + Set_Is_Known_Valid (Entity (Actual), False); + end if; + + -- For an OUT or IN OUT parameter, if the actual is an entity, then + -- clear current values, since they can be clobbered. We are probably + -- doing this in more places than we need to, but better safe than + -- sorry when it comes to retaining bad current values. + + if Ekind (Formal) /= E_In_Parameter + and then Is_Entity_Name (Actual) + and then Present (Entity (Actual)) + then + declare + Ent : constant Entity_Id := Entity (Actual); + Sav : Node_Id; + + begin + -- For an OUT or IN OUT parameter that is an assignable entity, + -- we do not want to clobber the Last_Assignment field, since + -- if it is set, it was precisely because it is indeed an OUT + -- or IN OUT parameter. We do reset the Is_Known_Valid flag + -- since the subprogram could have returned in invalid value. + + if Ekind_In (Formal, E_Out_Parameter, E_In_Out_Parameter) + and then Is_Assignable (Ent) + then + Sav := Last_Assignment (Ent); + Kill_Current_Values (Ent); + Set_Last_Assignment (Ent, Sav); + Set_Is_Known_Valid (Ent, False); + + -- For all other cases, just kill the current values + + else + Kill_Current_Values (Ent); + end if; + end; + end if; + + -- If the formal is class wide and the actual is an aggregate, force + -- evaluation so that the back end who does not know about class-wide + -- type, does not generate a temporary of the wrong size. + + if not Is_Class_Wide_Type (Etype (Formal)) then + null; + + elsif Nkind (Actual) = N_Aggregate + or else (Nkind (Actual) = N_Qualified_Expression + and then Nkind (Expression (Actual)) = N_Aggregate) + then + Force_Evaluation (Actual); + end if; + + -- In a remote call, if the formal is of a class-wide type, check + -- that the actual meets the requirements described in E.4(18). + + if Remote and then Is_Class_Wide_Type (Etype (Formal)) then + Insert_Action (Actual, + Make_Transportable_Check (Loc, + Duplicate_Subexpr_Move_Checks (Actual))); + end if; + + -- Perform invariant checks for all intermediate types in a view + -- conversion after successful return from a call that passes the + -- view conversion as an IN OUT or OUT parameter (RM 7.3.2 (12/3, + -- 13/3, 14/3)). Consider only source conversion in order to avoid + -- generating spurious checks on complex expansion such as object + -- initialization through an extension aggregate. + + if Comes_From_Source (N) + and then Ekind (Formal) /= E_In_Parameter + and then Nkind (Actual) = N_Type_Conversion + then + Add_View_Conversion_Invariants (Formal, Actual); + end if; + + -- Generating C the initialization of an allocator is performed by + -- means of individual statements, and hence it must be done before + -- the call. + + if Modify_Tree_For_C + and then Nkind (Actual) = N_Allocator + and then Nkind (Expression (Actual)) = N_Qualified_Expression + then + Remove_Side_Effects (Actual); + end if; + + -- This label is required when skipping extra actual generation for + -- Unchecked_Union parameters. + + <<Skip_Extra_Actual_Generation>> + + Param_Count := Param_Count + 1; + Next_Actual (Actual); + Next_Formal (Formal); + end loop; + + -- If we are calling an Ada 2012 function which needs to have the + -- "accessibility level determined by the point of call" (AI05-0234) + -- passed in to it, then pass it in. + + if Ekind_In (Subp, E_Function, E_Operator, E_Subprogram_Type) + and then + Present (Extra_Accessibility_Of_Result (Ultimate_Alias (Subp))) + then + declare + Ancestor : Node_Id := Parent (Call_Node); + Level : Node_Id := Empty; + Defer : Boolean := False; + + begin + -- Unimplemented: if Subp returns an anonymous access type, then + + -- a) if the call is the operand of an explict conversion, then + -- the target type of the conversion (a named access type) + -- determines the accessibility level pass in; + + -- b) if the call defines an access discriminant of an object + -- (e.g., the discriminant of an object being created by an + -- allocator, or the discriminant of a function result), + -- then the accessibility level to pass in is that of the + -- discriminated object being initialized). + + -- ??? + + while Nkind (Ancestor) = N_Qualified_Expression + loop + Ancestor := Parent (Ancestor); + end loop; + + case Nkind (Ancestor) is + when N_Allocator => + + -- At this point, we'd like to assign + + -- Level := Dynamic_Accessibility_Level (Ancestor); + + -- but Etype of Ancestor may not have been set yet, + -- so that doesn't work. + + -- Handle this later in Expand_Allocator_Expression. + + Defer := True; + + when N_Object_Declaration + | N_Object_Renaming_Declaration + => + declare + Def_Id : constant Entity_Id := + Defining_Identifier (Ancestor); + + begin + if Is_Return_Object (Def_Id) then + if Present (Extra_Accessibility_Of_Result + (Return_Applies_To (Scope (Def_Id)))) + then + -- Pass along value that was passed in if the + -- routine we are returning from also has an + -- Accessibility_Of_Result formal. + + Level := + New_Occurrence_Of + (Extra_Accessibility_Of_Result + (Return_Applies_To (Scope (Def_Id))), Loc); + end if; + else + Level := + Make_Integer_Literal (Loc, + Intval => Object_Access_Level (Def_Id)); + end if; + end; + + when N_Simple_Return_Statement => + if Present (Extra_Accessibility_Of_Result + (Return_Applies_To + (Return_Statement_Entity (Ancestor)))) + then + -- Pass along value that was passed in if the returned + -- routine also has an Accessibility_Of_Result formal. + + Level := + New_Occurrence_Of + (Extra_Accessibility_Of_Result + (Return_Applies_To + (Return_Statement_Entity (Ancestor))), Loc); + end if; + + when others => + null; + end case; + + if not Defer then + if not Present (Level) then + + -- The "innermost master that evaluates the function call". + + -- ??? - Should we use Integer'Last here instead in order + -- to deal with (some of) the problems associated with + -- calls to subps whose enclosing scope is unknown (e.g., + -- Anon_Access_To_Subp_Param.all)? + + Level := + Make_Integer_Literal (Loc, + Intval => Scope_Depth (Current_Scope) + 1); + end if; + + Add_Extra_Actual + (Expr => Level, + EF => + Extra_Accessibility_Of_Result (Ultimate_Alias (Subp))); + end if; + end; + end if; + + -- If we are expanding the RHS of an assignment we need to check if tag + -- propagation is needed. You might expect this processing to be in + -- Analyze_Assignment but has to be done earlier (bottom-up) because the + -- assignment might be transformed to a declaration for an unconstrained + -- value if the expression is classwide. + + if Nkind (Call_Node) = N_Function_Call + and then Is_Tag_Indeterminate (Call_Node) + and then Is_Entity_Name (Name (Call_Node)) + then + declare + Ass : Node_Id := Empty; + + begin + if Nkind (Parent (Call_Node)) = N_Assignment_Statement then + Ass := Parent (Call_Node); + + elsif Nkind (Parent (Call_Node)) = N_Qualified_Expression + and then Nkind (Parent (Parent (Call_Node))) = + N_Assignment_Statement + then + Ass := Parent (Parent (Call_Node)); + + elsif Nkind (Parent (Call_Node)) = N_Explicit_Dereference + and then Nkind (Parent (Parent (Call_Node))) = + N_Assignment_Statement + then + Ass := Parent (Parent (Call_Node)); + end if; + + if Present (Ass) + and then Is_Class_Wide_Type (Etype (Name (Ass))) + then + if Is_Access_Type (Etype (Call_Node)) then + if Designated_Type (Etype (Call_Node)) /= + Root_Type (Etype (Name (Ass))) + then + Error_Msg_NE + ("tag-indeterminate expression must have designated " + & "type& (RM 5.2 (6))", + Call_Node, Root_Type (Etype (Name (Ass)))); + else + Propagate_Tag (Name (Ass), Call_Node); + end if; + + elsif Etype (Call_Node) /= Root_Type (Etype (Name (Ass))) then + Error_Msg_NE + ("tag-indeterminate expression must have type & " + & "(RM 5.2 (6))", + Call_Node, Root_Type (Etype (Name (Ass)))); + + else + Propagate_Tag (Name (Ass), Call_Node); + end if; + + -- The call will be rewritten as a dispatching call, and + -- expanded as such. + + return; + end if; + end; + end if; + + -- Ada 2005 (AI-251): If some formal is a class-wide interface, expand + -- it to point to the correct secondary virtual table + + if Nkind (Call_Node) in N_Subprogram_Call + and then CW_Interface_Formals_Present + then + Expand_Interface_Actuals (Call_Node); + end if; + + -- Deals with Dispatch_Call if we still have a call, before expanding + -- extra actuals since this will be done on the re-analysis of the + -- dispatching call. Note that we do not try to shorten the actual list + -- for a dispatching call, it would not make sense to do so. Expansion + -- of dispatching calls is suppressed for VM targets, because the VM + -- back-ends directly handle the generation of dispatching calls and + -- would have to undo any expansion to an indirect call. + + if Nkind (Call_Node) in N_Subprogram_Call + and then Present (Controlling_Argument (Call_Node)) + then + declare + Call_Typ : constant Entity_Id := Etype (Call_Node); + Typ : constant Entity_Id := Find_Dispatching_Type (Subp); + Eq_Prim_Op : Entity_Id := Empty; + New_Call : Node_Id; + Param : Node_Id; + Prev_Call : Node_Id; + + begin + if not Is_Limited_Type (Typ) then + Eq_Prim_Op := Find_Prim_Op (Typ, Name_Op_Eq); + end if; + + if Tagged_Type_Expansion then + Expand_Dispatching_Call (Call_Node); + + -- The following return is worrisome. Is it really OK to skip + -- all remaining processing in this procedure ??? + + return; + + -- VM targets + + else + Apply_Tag_Checks (Call_Node); + + -- If this is a dispatching "=", we must first compare the + -- tags so we generate: x.tag = y.tag and then x = y + + if Subp = Eq_Prim_Op then + + -- Mark the node as analyzed to avoid reanalyzing this + -- dispatching call (which would cause a never-ending loop) + + Prev_Call := Relocate_Node (Call_Node); + Set_Analyzed (Prev_Call); + + Param := First_Actual (Call_Node); + New_Call := + Make_And_Then (Loc, + Left_Opnd => + Make_Op_Eq (Loc, + Left_Opnd => + Make_Selected_Component (Loc, + Prefix => New_Value (Param), + Selector_Name => + New_Occurrence_Of + (First_Tag_Component (Typ), Loc)), + + Right_Opnd => + Make_Selected_Component (Loc, + Prefix => + Unchecked_Convert_To (Typ, + New_Value (Next_Actual (Param))), + Selector_Name => + New_Occurrence_Of + (First_Tag_Component (Typ), Loc))), + Right_Opnd => Prev_Call); + + Rewrite (Call_Node, New_Call); + + Analyze_And_Resolve + (Call_Node, Call_Typ, Suppress => All_Checks); + end if; + + -- Expansion of a dispatching call results in an indirect call, + -- which in turn causes current values to be killed (see + -- Resolve_Call), so on VM targets we do the call here to + -- ensure consistent warnings between VM and non-VM targets. + + Kill_Current_Values; + end if; + + -- If this is a dispatching "=" then we must update the reference + -- to the call node because we generated: + -- x.tag = y.tag and then x = y + + if Subp = Eq_Prim_Op then + Call_Node := Right_Opnd (Call_Node); + end if; + end; + end if; + + -- Similarly, expand calls to RCI subprograms on which pragma + -- All_Calls_Remote applies. The rewriting will be reanalyzed + -- later. Do this only when the call comes from source since we + -- do not want such a rewriting to occur in expanded code. + + if Is_All_Remote_Call (Call_Node) then + Expand_All_Calls_Remote_Subprogram_Call (Call_Node); + + -- Similarly, do not add extra actuals for an entry call whose entity + -- is a protected procedure, or for an internal protected subprogram + -- call, because it will be rewritten as a protected subprogram call + -- and reanalyzed (see Expand_Protected_Subprogram_Call). + + elsif Is_Protected_Type (Scope (Subp)) + and then (Ekind (Subp) = E_Procedure + or else Ekind (Subp) = E_Function) + then + null; + + -- During that loop we gathered the extra actuals (the ones that + -- correspond to Extra_Formals), so now they can be appended. + + else + while Is_Non_Empty_List (Extra_Actuals) loop + Add_Actual_Parameter (Remove_Head (Extra_Actuals)); + end loop; + end if; + + -- At this point we have all the actuals, so this is the point at which + -- the various expansion activities for actuals is carried out. + + Expand_Actuals (Call_Node, Subp, Post_Call); + + -- Verify that the actuals do not share storage. This check must be done + -- on the caller side rather that inside the subprogram to avoid issues + -- of parameter passing. + + if Check_Aliasing_Of_Parameters then + Apply_Parameter_Aliasing_Checks (Call_Node, Subp); + end if; + + -- If the subprogram is a renaming, or if it is inherited, replace it in + -- the call with the name of the actual subprogram being called. If this + -- is a dispatching call, the run-time decides what to call. The Alias + -- attribute does not apply to entries. + + if Nkind (Call_Node) /= N_Entry_Call_Statement + and then No (Controlling_Argument (Call_Node)) + and then Present (Parent_Subp) + and then not Is_Direct_Deep_Call (Subp) + then + if Present (Inherited_From_Formal (Subp)) then + Parent_Subp := Inherited_From_Formal (Subp); + else + Parent_Subp := Ultimate_Alias (Parent_Subp); + end if; + + -- The below setting of Entity is suspect, see F109-018 discussion??? + + Set_Entity (Name (Call_Node), Parent_Subp); + + if Is_Abstract_Subprogram (Parent_Subp) + and then not In_Instance + then + Error_Msg_NE + ("cannot call abstract subprogram &!", + Name (Call_Node), Parent_Subp); + end if; + + -- Inspect all formals of derived subprogram Subp. Compare parameter + -- types with the parent subprogram and check whether an actual may + -- need a type conversion to the corresponding formal of the parent + -- subprogram. + + -- Not clear whether intrinsic subprograms need such conversions. ??? + + if not Is_Intrinsic_Subprogram (Parent_Subp) + or else Is_Generic_Instance (Parent_Subp) + then + declare + procedure Convert (Act : Node_Id; Typ : Entity_Id); + -- Rewrite node Act as a type conversion of Act to Typ. Analyze + -- and resolve the newly generated construct. + + ------------- + -- Convert -- + ------------- + + procedure Convert (Act : Node_Id; Typ : Entity_Id) is + begin + Rewrite (Act, OK_Convert_To (Typ, Relocate_Node (Act))); + Analyze (Act); + Resolve (Act, Typ); + end Convert; + + -- Local variables + + Actual_Typ : Entity_Id; + Formal_Typ : Entity_Id; + Parent_Typ : Entity_Id; + + begin + Actual := First_Actual (Call_Node); + Formal := First_Formal (Subp); + Parent_Formal := First_Formal (Parent_Subp); + while Present (Formal) loop + Actual_Typ := Etype (Actual); + Formal_Typ := Etype (Formal); + Parent_Typ := Etype (Parent_Formal); + + -- For an IN parameter of a scalar type, the parent formal + -- type and derived formal type differ or the parent formal + -- type and actual type do not match statically. + + if Is_Scalar_Type (Formal_Typ) + and then Ekind (Formal) = E_In_Parameter + and then Formal_Typ /= Parent_Typ + and then + not Subtypes_Statically_Match (Parent_Typ, Actual_Typ) + and then not Raises_Constraint_Error (Actual) + then + Convert (Actual, Parent_Typ); + Enable_Range_Check (Actual); + + -- If the actual has been marked as requiring a range + -- check, then generate it here. + + if Do_Range_Check (Actual) then + Generate_Range_Check + (Actual, Etype (Formal), CE_Range_Check_Failed); + end if; + + -- For access types, the parent formal type and actual type + -- differ. + + elsif Is_Access_Type (Formal_Typ) + and then Base_Type (Parent_Typ) /= Base_Type (Actual_Typ) + then + if Ekind (Formal) /= E_In_Parameter then + Convert (Actual, Parent_Typ); + + elsif Ekind (Parent_Typ) = E_Anonymous_Access_Type + and then Designated_Type (Parent_Typ) /= + Designated_Type (Actual_Typ) + and then not Is_Controlling_Formal (Formal) + then + -- This unchecked conversion is not necessary unless + -- inlining is enabled, because in that case the type + -- mismatch may become visible in the body about to be + -- inlined. + + Rewrite (Actual, + Unchecked_Convert_To (Parent_Typ, + Relocate_Node (Actual))); + Analyze (Actual); + Resolve (Actual, Parent_Typ); + end if; + + -- If there is a change of representation, then generate a + -- warning, and do the change of representation. + + elsif not Same_Representation (Formal_Typ, Parent_Typ) then + Error_Msg_N + ("??change of representation required", Actual); + Convert (Actual, Parent_Typ); + + -- For array and record types, the parent formal type and + -- derived formal type have different sizes or pragma Pack + -- status. + + elsif ((Is_Array_Type (Formal_Typ) + and then Is_Array_Type (Parent_Typ)) + or else + (Is_Record_Type (Formal_Typ) + and then Is_Record_Type (Parent_Typ))) + and then + (Esize (Formal_Typ) /= Esize (Parent_Typ) + or else Has_Pragma_Pack (Formal_Typ) /= + Has_Pragma_Pack (Parent_Typ)) + then + Convert (Actual, Parent_Typ); + end if; + + Next_Actual (Actual); + Next_Formal (Formal); + Next_Formal (Parent_Formal); + end loop; + end; + end if; + + Orig_Subp := Subp; + Subp := Parent_Subp; + end if; + + -- Deal with case where call is an explicit dereference + + if Nkind (Name (Call_Node)) = N_Explicit_Dereference then + + -- Handle case of access to protected subprogram type + + if Is_Access_Protected_Subprogram_Type + (Base_Type (Etype (Prefix (Name (Call_Node))))) + then + -- If this is a call through an access to protected operation, the + -- prefix has the form (object'address, operation'access). Rewrite + -- as a for other protected calls: the object is the 1st parameter + -- of the list of actuals. + + declare + Call : Node_Id; + Parm : List_Id; + Nam : Node_Id; + Obj : Node_Id; + Ptr : constant Node_Id := Prefix (Name (Call_Node)); + + T : constant Entity_Id := + Equivalent_Type (Base_Type (Etype (Ptr))); + + D_T : constant Entity_Id := + Designated_Type (Base_Type (Etype (Ptr))); + + begin + Obj := + Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => + New_Occurrence_Of (First_Entity (T), Loc)); + + Nam := + Make_Selected_Component (Loc, + Prefix => Unchecked_Convert_To (T, Ptr), + Selector_Name => + New_Occurrence_Of (Next_Entity (First_Entity (T)), Loc)); + + Nam := + Make_Explicit_Dereference (Loc, + Prefix => Nam); + + if Present (Parameter_Associations (Call_Node)) then + Parm := Parameter_Associations (Call_Node); + else + Parm := New_List; + end if; + + Prepend (Obj, Parm); + + if Etype (D_T) = Standard_Void_Type then + Call := + Make_Procedure_Call_Statement (Loc, + Name => Nam, + Parameter_Associations => Parm); + else + Call := + Make_Function_Call (Loc, + Name => Nam, + Parameter_Associations => Parm); + end if; + + Set_First_Named_Actual (Call, First_Named_Actual (Call_Node)); + Set_Etype (Call, Etype (D_T)); + + -- We do not re-analyze the call to avoid infinite recursion. + -- We analyze separately the prefix and the object, and set + -- the checks on the prefix that would otherwise be emitted + -- when resolving a call. + + Rewrite (Call_Node, Call); + Analyze (Nam); + Apply_Access_Check (Nam); + Analyze (Obj); + return; + end; + end if; + end if; + + -- If this is a call to an intrinsic subprogram, then perform the + -- appropriate expansion to the corresponding tree node and we + -- are all done (since after that the call is gone). + + -- In the case where the intrinsic is to be processed by the back end, + -- the call to Expand_Intrinsic_Call will do nothing, which is fine, + -- since the idea in this case is to pass the call unchanged. If the + -- intrinsic is an inherited unchecked conversion, and the derived type + -- is the target type of the conversion, we must retain it as the return + -- type of the expression. Otherwise the expansion below, which uses the + -- parent operation, will yield the wrong type. + + if Is_Intrinsic_Subprogram (Subp) then + Expand_Intrinsic_Call (Call_Node, Subp); + + if Nkind (Call_Node) = N_Unchecked_Type_Conversion + and then Parent_Subp /= Orig_Subp + and then Etype (Parent_Subp) /= Etype (Orig_Subp) + then + Set_Etype (Call_Node, Etype (Orig_Subp)); + end if; + + return; + end if; + + if Ekind_In (Subp, E_Function, E_Procedure) then + + -- We perform a simple optimization on calls for To_Address by + -- replacing them with an unchecked conversion. Not only is this + -- efficient, but it also avoids order of elaboration problems when + -- address clauses are inlined (address expression elaborated at the + -- wrong point). + + -- We perform this optimization regardless of whether we are in the + -- main unit or in a unit in the context of the main unit, to ensure + -- that the generated tree is the same in both cases, for CodePeer + -- use. + + if Is_RTE (Subp, RE_To_Address) then + Rewrite (Call_Node, + Unchecked_Convert_To + (RTE (RE_Address), Relocate_Node (First_Actual (Call_Node)))); + return; + + -- A call to a null procedure is replaced by a null statement, but we + -- are not allowed to ignore possible side effects of the call, so we + -- make sure that actuals are evaluated. + -- We also suppress this optimization for GNATCoverage. + + elsif Is_Null_Procedure (Subp) + and then not Opt.Suppress_Control_Flow_Optimizations + then + Actual := First_Actual (Call_Node); + while Present (Actual) loop + Remove_Side_Effects (Actual); + Next_Actual (Actual); + end loop; + + Rewrite (Call_Node, Make_Null_Statement (Loc)); + return; + end if; + + -- Handle inlining. No action needed if the subprogram is not inlined + + if not Is_Inlined (Subp) then + null; + + -- Frontend inlining of expression functions (performed also when + -- backend inlining is enabled). + + elsif Is_Inlinable_Expression_Function (Subp) then + Rewrite (N, New_Copy (Expression_Of_Expression_Function (Subp))); + Analyze (N); + return; + + -- Handle frontend inlining + + elsif not Back_End_Inlining then + Inlined_Subprogram : declare + Bod : Node_Id; + Must_Inline : Boolean := False; + Spec : constant Node_Id := Unit_Declaration_Node (Subp); + + begin + -- Verify that the body to inline has already been seen, and + -- that if the body is in the current unit the inlining does + -- not occur earlier. This avoids order-of-elaboration problems + -- in the back end. + + -- This should be documented in sinfo/einfo ??? + + if No (Spec) + or else Nkind (Spec) /= N_Subprogram_Declaration + or else No (Body_To_Inline (Spec)) + then + Must_Inline := False; + + -- If this an inherited function that returns a private type, + -- do not inline if the full view is an unconstrained array, + -- because such calls cannot be inlined. + + elsif Present (Orig_Subp) + and then Is_Array_Type (Etype (Orig_Subp)) + and then not Is_Constrained (Etype (Orig_Subp)) + then + Must_Inline := False; + + elsif In_Unfrozen_Instance (Scope (Subp)) then + Must_Inline := False; + + else + Bod := Body_To_Inline (Spec); + + if (In_Extended_Main_Code_Unit (Call_Node) + or else In_Extended_Main_Code_Unit (Parent (Call_Node)) + or else Has_Pragma_Inline_Always (Subp)) + and then (not In_Same_Extended_Unit (Sloc (Bod), Loc) + or else + Earlier_In_Extended_Unit (Sloc (Bod), Loc)) + then + Must_Inline := True; + + -- If we are compiling a package body that is not the main + -- unit, it must be for inlining/instantiation purposes, + -- in which case we inline the call to insure that the same + -- temporaries are generated when compiling the body by + -- itself. Otherwise link errors can occur. + + -- If the function being called is itself in the main unit, + -- we cannot inline, because there is a risk of double + -- elaboration and/or circularity: the inlining can make + -- visible a private entity in the body of the main unit, + -- that gigi will see before its sees its proper definition. + + elsif not (In_Extended_Main_Code_Unit (Call_Node)) + and then In_Package_Body + then + Must_Inline := not In_Extended_Main_Source_Unit (Subp); + + -- Inline calls to _postconditions when generating C code + + elsif Modify_Tree_For_C + and then In_Same_Extended_Unit (Sloc (Bod), Loc) + and then Chars (Name (N)) = Name_uPostconditions + then + Must_Inline := True; + end if; + end if; + + if Must_Inline then + Expand_Inlined_Call (Call_Node, Subp, Orig_Subp); + + else + -- Let the back end handle it + + Add_Inlined_Body (Subp, Call_Node); + + if Front_End_Inlining + and then Nkind (Spec) = N_Subprogram_Declaration + and then (In_Extended_Main_Code_Unit (Call_Node)) + and then No (Body_To_Inline (Spec)) + and then not Has_Completion (Subp) + and then In_Same_Extended_Unit (Sloc (Spec), Loc) + then + Cannot_Inline + ("cannot inline& (body not seen yet)?", + Call_Node, Subp); + end if; + end if; + end Inlined_Subprogram; + + -- Back end inlining: let the back end handle it + + elsif No (Unit_Declaration_Node (Subp)) + or else Nkind (Unit_Declaration_Node (Subp)) /= + N_Subprogram_Declaration + or else No (Body_To_Inline (Unit_Declaration_Node (Subp))) + or else Nkind (Body_To_Inline (Unit_Declaration_Node (Subp))) in + N_Entity + then + Add_Inlined_Body (Subp, Call_Node); + + -- If the inlined call appears within an instantiation and some + -- level of optimization is required, ensure that the enclosing + -- instance body is available so that the back-end can actually + -- perform the inlining. + + if In_Instance + and then Comes_From_Source (Subp) + and then Optimization_Level > 0 + then + declare + Decl : Node_Id; + Inst : Entity_Id; + Inst_Node : Node_Id; + + begin + Inst := Scope (Subp); + + -- Find enclosing instance + + while Present (Inst) and then Inst /= Standard_Standard loop + exit when Is_Generic_Instance (Inst); + Inst := Scope (Inst); + end loop; + + if Present (Inst) + and then Is_Generic_Instance (Inst) + and then not Is_Inlined (Inst) + then + Set_Is_Inlined (Inst); + Decl := Unit_Declaration_Node (Inst); + + -- Do not add a pending instantiation if the body exits + -- already, or if the instance is a compilation unit, or + -- the instance node is missing. + + if Present (Corresponding_Body (Decl)) + or else Nkind (Parent (Decl)) = N_Compilation_Unit + or else No (Next (Decl)) + then + null; + + else + -- The instantiation node usually follows the package + -- declaration for the instance. If the generic unit + -- has aspect specifications, they are transformed + -- into pragmas in the instance, and the instance node + -- appears after them. + + Inst_Node := Next (Decl); + + while Nkind (Inst_Node) /= N_Package_Instantiation loop + Inst_Node := Next (Inst_Node); + end loop; + + Add_Pending_Instantiation (Inst_Node, Decl); + end if; + end if; + end; + end if; + + -- Front end expansion of simple functions returning unconstrained + -- types (see Check_And_Split_Unconstrained_Function). Note that the + -- case of a simple renaming (Body_To_Inline in N_Entity above, see + -- also Build_Renamed_Body) cannot be expanded here because this may + -- give rise to order-of-elaboration issues for the types of the + -- parameters of the subprogram, if any. + + else + Expand_Inlined_Call (Call_Node, Subp, Orig_Subp); + end if; + end if; + + -- Check for protected subprogram. This is either an intra-object call, + -- or a protected function call. Protected procedure calls are rewritten + -- as entry calls and handled accordingly. + + -- In Ada 2005, this may be an indirect call to an access parameter that + -- is an access_to_subprogram. In that case the anonymous type has a + -- scope that is a protected operation, but the call is a regular one. + -- In either case do not expand call if subprogram is eliminated. + + Scop := Scope (Subp); + + if Nkind (Call_Node) /= N_Entry_Call_Statement + and then Is_Protected_Type (Scop) + and then Ekind (Subp) /= E_Subprogram_Type + and then not Is_Eliminated (Subp) + then + -- If the call is an internal one, it is rewritten as a call to the + -- corresponding unprotected subprogram. + + Expand_Protected_Subprogram_Call (Call_Node, Subp, Scop); + end if; + + -- Functions returning controlled objects need special attention. If + -- the return type is limited, then the context is initialization and + -- different processing applies. If the call is to a protected function, + -- the expansion above will call Expand_Call recursively. Otherwise the + -- function call is transformed into a temporary which obtains the + -- result from the secondary stack. + + if Needs_Finalization (Etype (Subp)) then + if not Is_Build_In_Place_Function_Call (Call_Node) + and then + (No (First_Formal (Subp)) + or else + not Is_Concurrent_Record_Type (Etype (First_Formal (Subp)))) + then + Expand_Ctrl_Function_Call (Call_Node); + + -- Build-in-place function calls which appear in anonymous contexts + -- need a transient scope to ensure the proper finalization of the + -- intermediate result after its use. + + elsif Is_Build_In_Place_Function_Call (Call_Node) + and then Nkind_In (Parent (Unqual_Conv (Call_Node)), + N_Attribute_Reference, + N_Function_Call, + N_Indexed_Component, + N_Object_Renaming_Declaration, + N_Procedure_Call_Statement, + N_Selected_Component, + N_Slice) + then + Establish_Transient_Scope (Call_Node, Sec_Stack => True); + end if; + end if; + end Expand_Call_Helper; + + ------------------------------- + -- Expand_Ctrl_Function_Call -- + ------------------------------- + + procedure Expand_Ctrl_Function_Call (N : Node_Id) is + function Is_Element_Reference (N : Node_Id) return Boolean; + -- Determine whether node N denotes a reference to an Ada 2012 container + -- element. + + -------------------------- + -- Is_Element_Reference -- + -------------------------- + + function Is_Element_Reference (N : Node_Id) return Boolean is + Ref : constant Node_Id := Original_Node (N); + + begin + -- Analysis marks an element reference by setting the generalized + -- indexing attribute of an indexed component before the component + -- is rewritten into a function call. + + return + Nkind (Ref) = N_Indexed_Component + and then Present (Generalized_Indexing (Ref)); + end Is_Element_Reference; + + -- Start of processing for Expand_Ctrl_Function_Call + + begin + -- Optimization, if the returned value (which is on the sec-stack) is + -- returned again, no need to copy/readjust/finalize, we can just pass + -- the value thru (see Expand_N_Simple_Return_Statement), and thus no + -- attachment is needed + + if Nkind (Parent (N)) = N_Simple_Return_Statement then + return; + end if; + + -- Resolution is now finished, make sure we don't start analysis again + -- because of the duplication. + + Set_Analyzed (N); + + -- A function which returns a controlled object uses the secondary + -- stack. Rewrite the call into a temporary which obtains the result of + -- the function using 'reference. + + Remove_Side_Effects (N); + + -- The side effect removal of the function call produced a temporary. + -- When the context is a case expression, if expression, or expression + -- with actions, the lifetime of the temporary must be extended to match + -- that of the context. Otherwise the function result will be finalized + -- too early and affect the result of the expression. To prevent this + -- unwanted effect, the temporary should not be considered for clean up + -- actions by the general finalization machinery. + + -- Exception to this rule are references to Ada 2012 container elements. + -- Such references must be finalized at the end of each iteration of the + -- related quantified expression, otherwise the container will remain + -- busy. + + if Nkind (N) = N_Explicit_Dereference + and then Within_Case_Or_If_Expression (N) + and then not Is_Element_Reference (N) + then + Set_Is_Ignored_Transient (Entity (Prefix (N))); + end if; + end Expand_Ctrl_Function_Call; + + ---------------------------------------- + -- Expand_N_Extended_Return_Statement -- + ---------------------------------------- + + -- If there is a Handled_Statement_Sequence, we rewrite this: + + -- return Result : T := <expression> do + -- <handled_seq_of_stms> + -- end return; + + -- to be: + + -- declare + -- Result : T := <expression>; + -- begin + -- <handled_seq_of_stms> + -- return Result; + -- end; + + -- Otherwise (no Handled_Statement_Sequence), we rewrite this: + + -- return Result : T := <expression>; + + -- to be: + + -- return <expression>; + + -- unless it's build-in-place or there's no <expression>, in which case + -- we generate: + + -- declare + -- Result : T := <expression>; + -- begin + -- return Result; + -- end; + + -- Note that this case could have been written by the user as an extended + -- return statement, or could have been transformed to this from a simple + -- return statement. + + -- That is, we need to have a reified return object if there are statements + -- (which might refer to it) or if we're doing build-in-place (so we can + -- set its address to the final resting place or if there is no expression + -- (in which case default initial values might need to be set). + + procedure Expand_N_Extended_Return_Statement (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + + function Build_Heap_Allocator + (Temp_Id : Entity_Id; + Temp_Typ : Entity_Id; + Func_Id : Entity_Id; + Ret_Typ : Entity_Id; + Alloc_Expr : Node_Id) return Node_Id; + -- Create the statements necessary to allocate a return object on the + -- caller's master. The master is available through implicit parameter + -- BIPfinalizationmaster. + -- + -- if BIPfinalizationmaster /= null then + -- declare + -- type Ptr_Typ is access Ret_Typ; + -- for Ptr_Typ'Storage_Pool use + -- Base_Pool (BIPfinalizationmaster.all).all; + -- Local : Ptr_Typ; + -- + -- begin + -- procedure Allocate (...) is + -- begin + -- System.Storage_Pools.Subpools.Allocate_Any (...); + -- end Allocate; + -- + -- Local := <Alloc_Expr>; + -- Temp_Id := Temp_Typ (Local); + -- end; + -- end if; + -- + -- Temp_Id is the temporary which is used to reference the internally + -- created object in all allocation forms. Temp_Typ is the type of the + -- temporary. Func_Id is the enclosing function. Ret_Typ is the return + -- type of Func_Id. Alloc_Expr is the actual allocator. + + function Move_Activation_Chain (Func_Id : Entity_Id) return Node_Id; + -- Construct a call to System.Tasking.Stages.Move_Activation_Chain + -- with parameters: + -- From current activation chain + -- To activation chain passed in by the caller + -- New_Master master passed in by the caller + -- + -- Func_Id is the entity of the function where the extended return + -- statement appears. + + -------------------------- + -- Build_Heap_Allocator -- + -------------------------- + + function Build_Heap_Allocator + (Temp_Id : Entity_Id; + Temp_Typ : Entity_Id; + Func_Id : Entity_Id; + Ret_Typ : Entity_Id; + Alloc_Expr : Node_Id) return Node_Id + is + begin + pragma Assert (Is_Build_In_Place_Function (Func_Id)); + + -- Processing for build-in-place object allocation. + + if Needs_Finalization (Ret_Typ) then + declare + Decls : constant List_Id := New_List; + Fin_Mas_Id : constant Entity_Id := + Build_In_Place_Formal + (Func_Id, BIP_Finalization_Master); + Stmts : constant List_Id := New_List; + Desig_Typ : Entity_Id; + Local_Id : Entity_Id; + Pool_Id : Entity_Id; + Ptr_Typ : Entity_Id; + + begin + -- Generate: + -- Pool_Id renames Base_Pool (BIPfinalizationmaster.all).all; + + Pool_Id := Make_Temporary (Loc, 'P'); + + Append_To (Decls, + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Pool_Id, + Subtype_Mark => + New_Occurrence_Of (RTE (RE_Root_Storage_Pool), Loc), + Name => + Make_Explicit_Dereference (Loc, + Prefix => + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Base_Pool), Loc), + Parameter_Associations => New_List ( + Make_Explicit_Dereference (Loc, + Prefix => + New_Occurrence_Of (Fin_Mas_Id, Loc))))))); + + -- Create an access type which uses the storage pool of the + -- caller's master. This additional type is necessary because + -- the finalization master cannot be associated with the type + -- of the temporary. Otherwise the secondary stack allocation + -- will fail. + + Desig_Typ := Ret_Typ; + + -- Ensure that the build-in-place machinery uses a fat pointer + -- when allocating an unconstrained array on the heap. In this + -- case the result object type is a constrained array type even + -- though the function type is unconstrained. + + if Ekind (Desig_Typ) = E_Array_Subtype then + Desig_Typ := Base_Type (Desig_Typ); + end if; + + -- Generate: + -- type Ptr_Typ is access Desig_Typ; + + Ptr_Typ := Make_Temporary (Loc, 'P'); + + Append_To (Decls, + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Ptr_Typ, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + Subtype_Indication => + New_Occurrence_Of (Desig_Typ, Loc)))); + + -- Perform minor decoration in order to set the master and the + -- storage pool attributes. + + Set_Ekind (Ptr_Typ, E_Access_Type); + Set_Finalization_Master (Ptr_Typ, Fin_Mas_Id); + Set_Associated_Storage_Pool (Ptr_Typ, Pool_Id); + + -- Create the temporary, generate: + -- Local_Id : Ptr_Typ; + + Local_Id := Make_Temporary (Loc, 'T'); + + Append_To (Decls, + Make_Object_Declaration (Loc, + Defining_Identifier => Local_Id, + Object_Definition => + New_Occurrence_Of (Ptr_Typ, Loc))); + + -- Allocate the object, generate: + -- Local_Id := <Alloc_Expr>; + + Append_To (Stmts, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Local_Id, Loc), + Expression => Alloc_Expr)); + + -- Generate: + -- Temp_Id := Temp_Typ (Local_Id); + + Append_To (Stmts, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Temp_Id, Loc), + Expression => + Unchecked_Convert_To (Temp_Typ, + New_Occurrence_Of (Local_Id, Loc)))); + + -- Wrap the allocation in a block. This is further conditioned + -- by checking the caller finalization master at runtime. A + -- null value indicates a non-existent master, most likely due + -- to a Finalize_Storage_Only allocation. + + -- Generate: + -- if BIPfinalizationmaster /= null then + -- declare + -- <Decls> + -- begin + -- <Stmts> + -- end; + -- end if; + + return + Make_If_Statement (Loc, + Condition => + Make_Op_Ne (Loc, + Left_Opnd => New_Occurrence_Of (Fin_Mas_Id, Loc), + Right_Opnd => Make_Null (Loc)), + + Then_Statements => New_List ( + Make_Block_Statement (Loc, + Declarations => Decls, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => Stmts)))); + end; + + -- For all other cases, generate: + -- Temp_Id := <Alloc_Expr>; + + else + return + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Temp_Id, Loc), + Expression => Alloc_Expr); + end if; + end Build_Heap_Allocator; + + --------------------------- + -- Move_Activation_Chain -- + --------------------------- + + function Move_Activation_Chain (Func_Id : Entity_Id) return Node_Id is + begin + return + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (RTE (RE_Move_Activation_Chain), Loc), + + Parameter_Associations => New_List ( + + -- Source chain + + Make_Attribute_Reference (Loc, + Prefix => Make_Identifier (Loc, Name_uChain), + Attribute_Name => Name_Unrestricted_Access), + + -- Destination chain + + New_Occurrence_Of + (Build_In_Place_Formal (Func_Id, BIP_Activation_Chain), Loc), + + -- New master + + New_Occurrence_Of + (Build_In_Place_Formal (Func_Id, BIP_Task_Master), Loc))); + end Move_Activation_Chain; + + -- Local variables + + Func_Id : constant Entity_Id := + Return_Applies_To (Return_Statement_Entity (N)); + Is_BIP_Func : constant Boolean := + Is_Build_In_Place_Function (Func_Id); + Ret_Obj_Id : constant Entity_Id := + First_Entity (Return_Statement_Entity (N)); + Ret_Obj_Decl : constant Node_Id := Parent (Ret_Obj_Id); + Ret_Typ : constant Entity_Id := Etype (Func_Id); + + Exp : Node_Id; + HSS : Node_Id; + Result : Node_Id; + Return_Stmt : Node_Id; + Stmts : List_Id; + + -- Start of processing for Expand_N_Extended_Return_Statement + + begin + -- Given that functionality of interface thunks is simple (just displace + -- the pointer to the object) they are always handled by means of + -- simple return statements. + + pragma Assert (not Is_Thunk (Current_Scope)); + + if Nkind (Ret_Obj_Decl) = N_Object_Declaration then + Exp := Expression (Ret_Obj_Decl); + else + Exp := Empty; + end if; + + HSS := Handled_Statement_Sequence (N); + + -- If the returned object needs finalization actions, the function must + -- perform the appropriate cleanup should it fail to return. The state + -- of the function itself is tracked through a flag which is coupled + -- with the scope finalizer. There is one flag per each return object + -- in case of multiple returns. + + if Is_BIP_Func and then Needs_Finalization (Etype (Ret_Obj_Id)) then + declare + Flag_Decl : Node_Id; + Flag_Id : Entity_Id; + Func_Bod : Node_Id; + + begin + -- Recover the function body + + Func_Bod := Unit_Declaration_Node (Func_Id); + + if Nkind (Func_Bod) = N_Subprogram_Declaration then + Func_Bod := Parent (Parent (Corresponding_Body (Func_Bod))); + end if; + + if Nkind (Func_Bod) = N_Function_Specification then + Func_Bod := Parent (Func_Bod); -- one more level for child units + end if; + + pragma Assert (Nkind (Func_Bod) = N_Subprogram_Body); + + -- Create a flag to track the function state + + Flag_Id := Make_Temporary (Loc, 'F'); + Set_Status_Flag_Or_Transient_Decl (Ret_Obj_Id, Flag_Id); + + -- Insert the flag at the beginning of the function declarations, + -- generate: + -- Fnn : Boolean := False; + + Flag_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Flag_Id, + Object_Definition => + New_Occurrence_Of (Standard_Boolean, Loc), + Expression => + New_Occurrence_Of (Standard_False, Loc)); + + Prepend_To (Declarations (Func_Bod), Flag_Decl); + Analyze (Flag_Decl); + end; + end if; + + -- Build a simple_return_statement that returns the return object when + -- there is a statement sequence, or no expression, or the result will + -- be built in place. Note however that we currently do this for all + -- composite cases, even though not all are built in place. + + if Present (HSS) + or else Is_Composite_Type (Ret_Typ) + or else No (Exp) + then + if No (HSS) then + Stmts := New_List; + + -- If the extended return has a handled statement sequence, then wrap + -- it in a block and use the block as the first statement. + + else + Stmts := New_List ( + Make_Block_Statement (Loc, + Declarations => New_List, + Handled_Statement_Sequence => HSS)); + end if; + + -- If the result type contains tasks, we call Move_Activation_Chain. + -- Later, the cleanup code will call Complete_Master, which will + -- terminate any unactivated tasks belonging to the return statement + -- master. But Move_Activation_Chain updates their master to be that + -- of the caller, so they will not be terminated unless the return + -- statement completes unsuccessfully due to exception, abort, goto, + -- or exit. As a formality, we test whether the function requires the + -- result to be built in place, though that's necessarily true for + -- the case of result types with task parts. + + if Is_BIP_Func and then Has_Task (Ret_Typ) then + + -- The return expression is an aggregate for a complex type which + -- contains tasks. This particular case is left unexpanded since + -- the regular expansion would insert all temporaries and + -- initialization code in the wrong block. + + if Nkind (Exp) = N_Aggregate then + Expand_N_Aggregate (Exp); + end if; + + -- Do not move the activation chain if the return object does not + -- contain tasks. + + if Has_Task (Etype (Ret_Obj_Id)) then + Append_To (Stmts, Move_Activation_Chain (Func_Id)); + end if; + end if; + + -- Update the state of the function right before the object is + -- returned. + + if Is_BIP_Func and then Needs_Finalization (Etype (Ret_Obj_Id)) then + declare + Flag_Id : constant Entity_Id := + Status_Flag_Or_Transient_Decl (Ret_Obj_Id); + + begin + -- Generate: + -- Fnn := True; + + Append_To (Stmts, + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Flag_Id, Loc), + Expression => New_Occurrence_Of (Standard_True, Loc))); + end; + end if; + + -- Build a simple_return_statement that returns the return object + + Return_Stmt := + Make_Simple_Return_Statement (Loc, + Expression => New_Occurrence_Of (Ret_Obj_Id, Loc)); + Append_To (Stmts, Return_Stmt); + + HSS := Make_Handled_Sequence_Of_Statements (Loc, Stmts); + end if; + + -- Case where we build a return statement block + + if Present (HSS) then + Result := + Make_Block_Statement (Loc, + Declarations => Return_Object_Declarations (N), + Handled_Statement_Sequence => HSS); + + -- We set the entity of the new block statement to be that of the + -- return statement. This is necessary so that various fields, such + -- as Finalization_Chain_Entity carry over from the return statement + -- to the block. Note that this block is unusual, in that its entity + -- is an E_Return_Statement rather than an E_Block. + + Set_Identifier + (Result, New_Occurrence_Of (Return_Statement_Entity (N), Loc)); + + -- If the object decl was already rewritten as a renaming, then we + -- don't want to do the object allocation and transformation of + -- the return object declaration to a renaming. This case occurs + -- when the return object is initialized by a call to another + -- build-in-place function, and that function is responsible for + -- the allocation of the return object. + + if Is_BIP_Func + and then Nkind (Ret_Obj_Decl) = N_Object_Renaming_Declaration + then + pragma Assert + (Nkind (Original_Node (Ret_Obj_Decl)) = N_Object_Declaration + and then + + -- It is a regular BIP object declaration + + (Is_Build_In_Place_Function_Call + (Expression (Original_Node (Ret_Obj_Decl))) + + -- It is a BIP object declaration that displaces the pointer + -- to the object to reference a convered interface type. + + or else + Present (Unqual_BIP_Iface_Function_Call + (Expression (Original_Node (Ret_Obj_Decl)))))); + + -- Return the build-in-place result by reference + + Set_By_Ref (Return_Stmt); + + elsif Is_BIP_Func then + + -- Locate the implicit access parameter associated with the + -- caller-supplied return object and convert the return + -- statement's return object declaration to a renaming of a + -- dereference of the access parameter. If the return object's + -- declaration includes an expression that has not already been + -- expanded as separate assignments, then add an assignment + -- statement to ensure the return object gets initialized. + + -- declare + -- Result : T [:= <expression>]; + -- begin + -- ... + + -- is converted to + + -- declare + -- Result : T renames FuncRA.all; + -- [Result := <expression;] + -- begin + -- ... + + declare + Ret_Obj_Expr : constant Node_Id := Expression (Ret_Obj_Decl); + Ret_Obj_Typ : constant Entity_Id := Etype (Ret_Obj_Id); + + Init_Assignment : Node_Id := Empty; + Obj_Acc_Formal : Entity_Id; + Obj_Acc_Deref : Node_Id; + Obj_Alloc_Formal : Entity_Id; + + begin + -- Build-in-place results must be returned by reference + + Set_By_Ref (Return_Stmt); + + -- Retrieve the implicit access parameter passed by the caller + + Obj_Acc_Formal := + Build_In_Place_Formal (Func_Id, BIP_Object_Access); + + -- If the return object's declaration includes an expression + -- and the declaration isn't marked as No_Initialization, then + -- we need to generate an assignment to the object and insert + -- it after the declaration before rewriting it as a renaming + -- (otherwise we'll lose the initialization). The case where + -- the result type is an interface (or class-wide interface) + -- is also excluded because the context of the function call + -- must be unconstrained, so the initialization will always + -- be done as part of an allocator evaluation (storage pool + -- or secondary stack), never to a constrained target object + -- passed in by the caller. Besides the assignment being + -- unneeded in this case, it avoids problems with trying to + -- generate a dispatching assignment when the return expression + -- is a nonlimited descendant of a limited interface (the + -- interface has no assignment operation). + + if Present (Ret_Obj_Expr) + and then not No_Initialization (Ret_Obj_Decl) + and then not Is_Interface (Ret_Obj_Typ) + then + Init_Assignment := + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Ret_Obj_Id, Loc), + Expression => New_Copy_Tree (Ret_Obj_Expr)); + + Set_Etype (Name (Init_Assignment), Etype (Ret_Obj_Id)); + Set_Assignment_OK (Name (Init_Assignment)); + Set_No_Ctrl_Actions (Init_Assignment); + + Set_Parent (Name (Init_Assignment), Init_Assignment); + Set_Parent (Expression (Init_Assignment), Init_Assignment); + + Set_Expression (Ret_Obj_Decl, Empty); + + if Is_Class_Wide_Type (Etype (Ret_Obj_Id)) + and then not Is_Class_Wide_Type + (Etype (Expression (Init_Assignment))) + then + Rewrite (Expression (Init_Assignment), + Make_Type_Conversion (Loc, + Subtype_Mark => + New_Occurrence_Of (Etype (Ret_Obj_Id), Loc), + Expression => + Relocate_Node (Expression (Init_Assignment)))); + end if; + + -- In the case of functions where the calling context can + -- determine the form of allocation needed, initialization + -- is done with each part of the if statement that handles + -- the different forms of allocation (this is true for + -- unconstrained and tagged result subtypes). + + if Is_Constrained (Ret_Typ) + and then not Is_Tagged_Type (Underlying_Type (Ret_Typ)) + then + Insert_After (Ret_Obj_Decl, Init_Assignment); + end if; + end if; + + -- When the function's subtype is unconstrained, a run-time + -- test is needed to determine the form of allocation to use + -- for the return object. The function has an implicit formal + -- parameter indicating this. If the BIP_Alloc_Form formal has + -- the value one, then the caller has passed access to an + -- existing object for use as the return object. If the value + -- is two, then the return object must be allocated on the + -- secondary stack. Otherwise, the object must be allocated in + -- a storage pool. We generate an if statement to test the + -- implicit allocation formal and initialize a local access + -- value appropriately, creating allocators in the secondary + -- stack and global heap cases. The special formal also exists + -- and must be tested when the function has a tagged result, + -- even when the result subtype is constrained, because in + -- general such functions can be called in dispatching contexts + -- and must be handled similarly to functions with a class-wide + -- result. + + if not Is_Constrained (Ret_Typ) + or else Is_Tagged_Type (Underlying_Type (Ret_Typ)) + then + Obj_Alloc_Formal := + Build_In_Place_Formal (Func_Id, BIP_Alloc_Form); + + declare + Pool_Id : constant Entity_Id := + Make_Temporary (Loc, 'P'); + Alloc_Obj_Id : Entity_Id; + Alloc_Obj_Decl : Node_Id; + Alloc_If_Stmt : Node_Id; + Heap_Allocator : Node_Id; + Pool_Decl : Node_Id; + Pool_Allocator : Node_Id; + Ptr_Type_Decl : Node_Id; + Ref_Type : Entity_Id; + SS_Allocator : Node_Id; + + begin + -- Reuse the itype created for the function's implicit + -- access formal. This avoids the need to create a new + -- access type here, plus it allows assigning the access + -- formal directly without applying a conversion. + + -- Ref_Type := Etype (Object_Access); + + -- Create an access type designating the function's + -- result subtype. + + Ref_Type := Make_Temporary (Loc, 'A'); + + Ptr_Type_Decl := + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Ref_Type, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + All_Present => True, + Subtype_Indication => + New_Occurrence_Of (Ret_Obj_Typ, Loc))); + + Insert_Before (Ret_Obj_Decl, Ptr_Type_Decl); + + -- Create an access object that will be initialized to an + -- access value denoting the return object, either coming + -- from an implicit access value passed in by the caller + -- or from the result of an allocator. + + Alloc_Obj_Id := Make_Temporary (Loc, 'R'); + Set_Etype (Alloc_Obj_Id, Ref_Type); + + Alloc_Obj_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Alloc_Obj_Id, + Object_Definition => + New_Occurrence_Of (Ref_Type, Loc)); + + Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl); + + -- Create allocators for both the secondary stack and + -- global heap. If there's an initialization expression, + -- then create these as initialized allocators. + + if Present (Ret_Obj_Expr) + and then not No_Initialization (Ret_Obj_Decl) + then + -- Always use the type of the expression for the + -- qualified expression, rather than the result type. + -- In general we cannot always use the result type + -- for the allocator, because the expression might be + -- of a specific type, such as in the case of an + -- aggregate or even a nonlimited object when the + -- result type is a limited class-wide interface type. + + Heap_Allocator := + Make_Allocator (Loc, + Expression => + Make_Qualified_Expression (Loc, + Subtype_Mark => + New_Occurrence_Of + (Etype (Ret_Obj_Expr), Loc), + Expression => New_Copy_Tree (Ret_Obj_Expr))); + + else + -- If the function returns a class-wide type we cannot + -- use the return type for the allocator. Instead we + -- use the type of the expression, which must be an + -- aggregate of a definite type. + + if Is_Class_Wide_Type (Ret_Obj_Typ) then + Heap_Allocator := + Make_Allocator (Loc, + Expression => + New_Occurrence_Of + (Etype (Ret_Obj_Expr), Loc)); + else + Heap_Allocator := + Make_Allocator (Loc, + Expression => + New_Occurrence_Of (Ret_Obj_Typ, Loc)); + end if; + + -- If the object requires default initialization then + -- that will happen later following the elaboration of + -- the object renaming. If we don't turn it off here + -- then the object will be default initialized twice. + + Set_No_Initialization (Heap_Allocator); + end if; + + -- Set the flag indicating that the allocator came from + -- a build-in-place return statement, so we can avoid + -- adjusting the allocated object. Note that this flag + -- will be inherited by the copies made below. + + Set_Alloc_For_BIP_Return (Heap_Allocator); + + -- The Pool_Allocator is just like the Heap_Allocator, + -- except we set Storage_Pool and Procedure_To_Call so + -- it will use the user-defined storage pool. + + Pool_Allocator := New_Copy_Tree (Heap_Allocator); + pragma Assert (Alloc_For_BIP_Return (Pool_Allocator)); + + -- Do not generate the renaming of the build-in-place + -- pool parameter on ZFP because the parameter is not + -- created in the first place. + + if RTE_Available (RE_Root_Storage_Pool_Ptr) then + Pool_Decl := + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Pool_Id, + Subtype_Mark => + New_Occurrence_Of + (RTE (RE_Root_Storage_Pool), Loc), + Name => + Make_Explicit_Dereference (Loc, + New_Occurrence_Of + (Build_In_Place_Formal + (Func_Id, BIP_Storage_Pool), Loc))); + Set_Storage_Pool (Pool_Allocator, Pool_Id); + Set_Procedure_To_Call + (Pool_Allocator, RTE (RE_Allocate_Any)); + else + Pool_Decl := Make_Null_Statement (Loc); + end if; + + -- If the No_Allocators restriction is active, then only + -- an allocator for secondary stack allocation is needed. + -- It's OK for such allocators to have Comes_From_Source + -- set to False, because gigi knows not to flag them as + -- being a violation of No_Implicit_Heap_Allocations. + + if Restriction_Active (No_Allocators) then + SS_Allocator := Heap_Allocator; + Heap_Allocator := Make_Null (Loc); + Pool_Allocator := Make_Null (Loc); + + -- Otherwise the heap and pool allocators may be needed, + -- so we make another allocator for secondary stack + -- allocation. + + else + SS_Allocator := New_Copy_Tree (Heap_Allocator); + pragma Assert (Alloc_For_BIP_Return (SS_Allocator)); + + -- The heap and pool allocators are marked as + -- Comes_From_Source since they correspond to an + -- explicit user-written allocator (that is, it will + -- only be executed on behalf of callers that call the + -- function as initialization for such an allocator). + -- Prevents errors when No_Implicit_Heap_Allocations + -- is in force. + + Set_Comes_From_Source (Heap_Allocator, True); + Set_Comes_From_Source (Pool_Allocator, True); + end if; + + -- The allocator is returned on the secondary stack. + + Set_Storage_Pool (SS_Allocator, RTE (RE_SS_Pool)); + Set_Procedure_To_Call + (SS_Allocator, RTE (RE_SS_Allocate)); + + -- The allocator is returned on the secondary stack, + -- so indicate that the function return, as well as + -- all blocks that encloses the allocator, must not + -- release it. The flags must be set now because + -- the decision to use the secondary stack is done + -- very late in the course of expanding the return + -- statement, past the point where these flags are + -- normally set. + + Set_Uses_Sec_Stack (Func_Id); + Set_Uses_Sec_Stack (Return_Statement_Entity (N)); + Set_Sec_Stack_Needed_For_Return + (Return_Statement_Entity (N)); + Set_Enclosing_Sec_Stack_Return (N); + + -- Create an if statement to test the BIP_Alloc_Form + -- formal and initialize the access object to either the + -- BIP_Object_Access formal (BIP_Alloc_Form = + -- Caller_Allocation), the result of allocating the + -- object in the secondary stack (BIP_Alloc_Form = + -- Secondary_Stack), or else an allocator to create the + -- return object in the heap or user-defined pool + -- (BIP_Alloc_Form = Global_Heap or User_Storage_Pool). + + -- ??? An unchecked type conversion must be made in the + -- case of assigning the access object formal to the + -- local access object, because a normal conversion would + -- be illegal in some cases (such as converting access- + -- to-unconstrained to access-to-constrained), but the + -- the unchecked conversion will presumably fail to work + -- right in just such cases. It's not clear at all how to + -- handle this. ??? + + Alloc_If_Stmt := + Make_If_Statement (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + New_Occurrence_Of (Obj_Alloc_Formal, Loc), + Right_Opnd => + Make_Integer_Literal (Loc, + UI_From_Int (BIP_Allocation_Form'Pos + (Caller_Allocation)))), + + Then_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => + New_Occurrence_Of (Alloc_Obj_Id, Loc), + Expression => + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => + New_Occurrence_Of (Ref_Type, Loc), + Expression => + New_Occurrence_Of (Obj_Acc_Formal, Loc)))), + + Elsif_Parts => New_List ( + Make_Elsif_Part (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + New_Occurrence_Of (Obj_Alloc_Formal, Loc), + Right_Opnd => + Make_Integer_Literal (Loc, + UI_From_Int (BIP_Allocation_Form'Pos + (Secondary_Stack)))), + + Then_Statements => New_List ( + Make_Assignment_Statement (Loc, + Name => + New_Occurrence_Of (Alloc_Obj_Id, Loc), + Expression => SS_Allocator))), + + Make_Elsif_Part (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + New_Occurrence_Of (Obj_Alloc_Formal, Loc), + Right_Opnd => + Make_Integer_Literal (Loc, + UI_From_Int (BIP_Allocation_Form'Pos + (Global_Heap)))), + + Then_Statements => New_List ( + Build_Heap_Allocator + (Temp_Id => Alloc_Obj_Id, + Temp_Typ => Ref_Type, + Func_Id => Func_Id, + Ret_Typ => Ret_Obj_Typ, + Alloc_Expr => Heap_Allocator))), + + -- ???If all is well, we can put the following + -- 'elsif' in the 'else', but this is a useful + -- self-check in case caller and callee don't agree + -- on whether BIPAlloc and so on should be passed. + + Make_Elsif_Part (Loc, + Condition => + Make_Op_Eq (Loc, + Left_Opnd => + New_Occurrence_Of (Obj_Alloc_Formal, Loc), + Right_Opnd => + Make_Integer_Literal (Loc, + UI_From_Int (BIP_Allocation_Form'Pos + (User_Storage_Pool)))), + + Then_Statements => New_List ( + Pool_Decl, + Build_Heap_Allocator + (Temp_Id => Alloc_Obj_Id, + Temp_Typ => Ref_Type, + Func_Id => Func_Id, + Ret_Typ => Ret_Obj_Typ, + Alloc_Expr => Pool_Allocator)))), + + -- Raise Program_Error if it's none of the above; + -- this is a compiler bug. ???PE_All_Guards_Closed + -- is bogus; we should have a new code. + + Else_Statements => New_List ( + Make_Raise_Program_Error (Loc, + Reason => PE_All_Guards_Closed))); + + -- If a separate initialization assignment was created + -- earlier, append that following the assignment of the + -- implicit access formal to the access object, to ensure + -- that the return object is initialized in that case. In + -- this situation, the target of the assignment must be + -- rewritten to denote a dereference of the access to the + -- return object passed in by the caller. + + if Present (Init_Assignment) then + Rewrite (Name (Init_Assignment), + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Alloc_Obj_Id, Loc))); + + Set_Etype (Name (Init_Assignment), Etype (Ret_Obj_Id)); + + Append_To + (Then_Statements (Alloc_If_Stmt), Init_Assignment); + end if; + + Insert_Before (Ret_Obj_Decl, Alloc_If_Stmt); + + -- Remember the local access object for use in the + -- dereference of the renaming created below. + + Obj_Acc_Formal := Alloc_Obj_Id; + end; + end if; + + -- Replace the return object declaration with a renaming of a + -- dereference of the access value designating the return + -- object. + + Obj_Acc_Deref := + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Obj_Acc_Formal, Loc)); + + Rewrite (Ret_Obj_Decl, + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Ret_Obj_Id, + Access_Definition => Empty, + Subtype_Mark => New_Occurrence_Of (Ret_Obj_Typ, Loc), + Name => Obj_Acc_Deref)); + + Set_Renamed_Object (Ret_Obj_Id, Obj_Acc_Deref); + end; + end if; + + -- Case where we do not build a block + + else + -- We're about to drop Return_Object_Declarations on the floor, so + -- we need to insert it, in case it got expanded into useful code. + -- Remove side effects from expression, which may be duplicated in + -- subsequent checks (see Expand_Simple_Function_Return). + + Insert_List_Before (N, Return_Object_Declarations (N)); + Remove_Side_Effects (Exp); + + -- Build simple_return_statement that returns the expression directly + + Return_Stmt := Make_Simple_Return_Statement (Loc, Expression => Exp); + Result := Return_Stmt; + end if; + + -- Set the flag to prevent infinite recursion + + Set_Comes_From_Extended_Return_Statement (Return_Stmt); + + Rewrite (N, Result); + Analyze (N); + end Expand_N_Extended_Return_Statement; + + ---------------------------- + -- Expand_N_Function_Call -- + ---------------------------- + + procedure Expand_N_Function_Call (N : Node_Id) is + begin + Expand_Call (N); + end Expand_N_Function_Call; + + --------------------------------------- + -- Expand_N_Procedure_Call_Statement -- + --------------------------------------- + + procedure Expand_N_Procedure_Call_Statement (N : Node_Id) is + begin + Expand_Call (N); + end Expand_N_Procedure_Call_Statement; + + -------------------------------------- + -- Expand_N_Simple_Return_Statement -- + -------------------------------------- + + procedure Expand_N_Simple_Return_Statement (N : Node_Id) is + begin + -- Defend against previous errors (i.e. the return statement calls a + -- function that is not available in configurable runtime). + + if Present (Expression (N)) + and then Nkind (Expression (N)) = N_Empty + then + Check_Error_Detected; + return; + end if; + + -- Distinguish the function and non-function cases: + + case Ekind (Return_Applies_To (Return_Statement_Entity (N))) is + when E_Function + | E_Generic_Function + => + Expand_Simple_Function_Return (N); + + when E_Entry + | E_Entry_Family + | E_Generic_Procedure + | E_Procedure + | E_Return_Statement + => + Expand_Non_Function_Return (N); + + when others => + raise Program_Error; + end case; + + exception + when RE_Not_Available => + return; + end Expand_N_Simple_Return_Statement; + + ------------------------------ + -- Expand_N_Subprogram_Body -- + ------------------------------ + + -- Add poll call if ATC polling is enabled, unless the body will be inlined + -- by the back-end. + + -- Add dummy push/pop label nodes at start and end to clear any local + -- exception indications if local-exception-to-goto optimization is active. + + -- Add return statement if last statement in body is not a return statement + -- (this makes things easier on Gigi which does not want to have to handle + -- a missing return). + + -- Add call to Activate_Tasks if body is a task activator + + -- Deal with possible detection of infinite recursion + + -- Eliminate body completely if convention stubbed + + -- Encode entity names within body, since we will not need to reference + -- these entities any longer in the front end. + + -- Initialize scalar out parameters if Initialize/Normalize_Scalars + + -- Reset Pure indication if any parameter has root type System.Address + -- or has any parameters of limited types, where limited means that the + -- run-time view is limited (i.e. the full type is limited). + + -- Wrap thread body + + procedure Expand_N_Subprogram_Body (N : Node_Id) is + Body_Id : constant Entity_Id := Defining_Entity (N); + HSS : constant Node_Id := Handled_Statement_Sequence (N); + Loc : constant Source_Ptr := Sloc (N); + + procedure Add_Return (Spec_Id : Entity_Id; Stmts : List_Id); + -- Append a return statement to the statement sequence Stmts if the last + -- statement is not already a return or a goto statement. Note that the + -- latter test is not critical, it does not matter if we add a few extra + -- returns, since they get eliminated anyway later on. Spec_Id denotes + -- the corresponding spec of the subprogram body. + + ---------------- + -- Add_Return -- + ---------------- + + procedure Add_Return (Spec_Id : Entity_Id; Stmts : List_Id) is + Last_Stmt : Node_Id; + Loc : Source_Ptr; + Stmt : Node_Id; + + begin + -- Get last statement, ignoring any Pop_xxx_Label nodes, which are + -- not relevant in this context since they are not executable. + + Last_Stmt := Last (Stmts); + while Nkind (Last_Stmt) in N_Pop_xxx_Label loop + Prev (Last_Stmt); + end loop; + + -- Now insert return unless last statement is a transfer + + if not Is_Transfer (Last_Stmt) then + + -- The source location for the return is the end label of the + -- procedure if present. Otherwise use the sloc of the last + -- statement in the list. If the list comes from a generated + -- exception handler and we are not debugging generated code, + -- all the statements within the handler are made invisible + -- to the debugger. + + if Nkind (Parent (Stmts)) = N_Exception_Handler + and then not Comes_From_Source (Parent (Stmts)) + then + Loc := Sloc (Last_Stmt); + elsif Present (End_Label (HSS)) then + Loc := Sloc (End_Label (HSS)); + else + Loc := Sloc (Last_Stmt); + end if; + + -- Append return statement, and set analyzed manually. We can't + -- call Analyze on this return since the scope is wrong. + + -- Note: it almost works to push the scope and then do the Analyze + -- call, but something goes wrong in some weird cases and it is + -- not worth worrying about ??? + + Stmt := Make_Simple_Return_Statement (Loc); + + -- The return statement is handled properly, and the call to the + -- postcondition, inserted below, does not require information + -- from the body either. However, that call is analyzed in the + -- enclosing scope, and an elaboration check might improperly be + -- added to it. A guard in Sem_Elab is needed to prevent that + -- spurious check, see Check_Elab_Call. + + Append_To (Stmts, Stmt); + Set_Analyzed (Stmt); + + -- Call the _Postconditions procedure if the related subprogram + -- has contract assertions that need to be verified on exit. + + if Ekind (Spec_Id) = E_Procedure + and then Present (Postconditions_Proc (Spec_Id)) + then + Insert_Action (Stmt, + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (Postconditions_Proc (Spec_Id), Loc))); + end if; + end if; + end Add_Return; + + -- Local variables + + Except_H : Node_Id; + L : List_Id; + Spec_Id : Entity_Id; + + -- Start of processing for Expand_N_Subprogram_Body + + begin + if Present (Corresponding_Spec (N)) then + Spec_Id := Corresponding_Spec (N); + else + Spec_Id := Body_Id; + end if; + + -- If this is a Pure function which has any parameters whose root type + -- is System.Address, reset the Pure indication. + -- This check is also performed when the subprogram is frozen, but we + -- repeat it on the body so that the indication is consistent, and so + -- it applies as well to bodies without separate specifications. + + if Is_Pure (Spec_Id) + and then Is_Subprogram (Spec_Id) + and then not Has_Pragma_Pure_Function (Spec_Id) + then + Check_Function_With_Address_Parameter (Spec_Id); + + if Spec_Id /= Body_Id then + Set_Is_Pure (Body_Id, Is_Pure (Spec_Id)); + end if; + end if; + + -- Set L to either the list of declarations if present, or to the list + -- of statements if no declarations are present. This is used to insert + -- new stuff at the start. + + if Is_Non_Empty_List (Declarations (N)) then + L := Declarations (N); + else + L := Statements (HSS); + end if; + + -- If local-exception-to-goto optimization active, insert dummy push + -- statements at start, and dummy pop statements at end, but inhibit + -- this if we have No_Exception_Handlers, since they are useless and + -- intefere with analysis, e.g. by codepeer. + + if (Debug_Flag_Dot_G + or else Restriction_Active (No_Exception_Propagation)) + and then not Restriction_Active (No_Exception_Handlers) + and then not CodePeer_Mode + and then Is_Non_Empty_List (L) + then + declare + FS : constant Node_Id := First (L); + FL : constant Source_Ptr := Sloc (FS); + LS : Node_Id; + LL : Source_Ptr; + + begin + -- LS points to either last statement, if statements are present + -- or to the last declaration if there are no statements present. + -- It is the node after which the pop's are generated. + + if Is_Non_Empty_List (Statements (HSS)) then + LS := Last (Statements (HSS)); + else + LS := Last (L); + end if; + + LL := Sloc (LS); + + Insert_List_Before_And_Analyze (FS, New_List ( + Make_Push_Constraint_Error_Label (FL), + Make_Push_Program_Error_Label (FL), + Make_Push_Storage_Error_Label (FL))); + + Insert_List_After_And_Analyze (LS, New_List ( + Make_Pop_Constraint_Error_Label (LL), + Make_Pop_Program_Error_Label (LL), + Make_Pop_Storage_Error_Label (LL))); + end; + end if; + + -- Need poll on entry to subprogram if polling enabled. We only do this + -- for non-empty subprograms, since it does not seem necessary to poll + -- for a dummy null subprogram. + + if Is_Non_Empty_List (L) then + + -- Do not add a polling call if the subprogram is to be inlined by + -- the back-end, to avoid repeated calls with multiple inlinings. + + if Is_Inlined (Spec_Id) + and then Front_End_Inlining + and then Optimization_Level > 1 + then + null; + else + Generate_Poll_Call (First (L)); + end if; + end if; + + -- Initialize any scalar OUT args if Initialize/Normalize_Scalars + + if Init_Or_Norm_Scalars and then Is_Subprogram (Spec_Id) then + declare + F : Entity_Id; + A : Node_Id; + + begin + -- Loop through formals + + F := First_Formal (Spec_Id); + while Present (F) loop + if Is_Scalar_Type (Etype (F)) + and then Ekind (F) = E_Out_Parameter + then + Check_Restriction (No_Default_Initialization, F); + + -- Insert the initialization. We turn off validity checks + -- for this assignment, since we do not want any check on + -- the initial value itself (which may well be invalid). + -- Predicate checks are disabled as well (RM 6.4.1 (13/3)) + + A := + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (F, Loc), + Expression => Get_Simple_Init_Val (Etype (F), N)); + Set_Suppress_Assignment_Checks (A); + + Insert_Before_And_Analyze (First (L), + A, Suppress => Validity_Check); + end if; + + Next_Formal (F); + end loop; + end; + end if; + + -- Clear out statement list for stubbed procedure + + if Present (Corresponding_Spec (N)) then + Set_Elaboration_Flag (N, Spec_Id); + + if Convention (Spec_Id) = Convention_Stubbed + or else Is_Eliminated (Spec_Id) + then + Set_Declarations (N, Empty_List); + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Make_Null_Statement (Loc)))); + + return; + end if; + end if; + + -- Create a set of discriminals for the next protected subprogram body + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + and then Present (Next_Protected_Operation (N)) + then + Set_Discriminals (Parent (Base_Type (Scope (Spec_Id)))); + end if; + + -- Returns_By_Ref flag is normally set when the subprogram is frozen but + -- subprograms with no specs are not frozen. + + declare + Typ : constant Entity_Id := Etype (Spec_Id); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if Is_Limited_View (Typ) then + Set_Returns_By_Ref (Spec_Id); + + elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then + Set_Returns_By_Ref (Spec_Id); + end if; + end; + + -- For a procedure, we add a return for all possible syntactic ends of + -- the subprogram. + + if Ekind_In (Spec_Id, E_Procedure, E_Generic_Procedure) then + Add_Return (Spec_Id, Statements (HSS)); + + if Present (Exception_Handlers (HSS)) then + Except_H := First_Non_Pragma (Exception_Handlers (HSS)); + while Present (Except_H) loop + Add_Return (Spec_Id, Statements (Except_H)); + Next_Non_Pragma (Except_H); + end loop; + end if; + + -- For a function, we must deal with the case where there is at least + -- one missing return. What we do is to wrap the entire body of the + -- function in a block: + + -- begin + -- ... + -- end; + + -- becomes + + -- begin + -- begin + -- ... + -- end; + + -- raise Program_Error; + -- end; + + -- This approach is necessary because the raise must be signalled to the + -- caller, not handled by any local handler (RM 6.4(11)). + + -- Note: we do not need to analyze the constructed sequence here, since + -- it has no handler, and an attempt to analyze the handled statement + -- sequence twice is risky in various ways (e.g. the issue of expanding + -- cleanup actions twice). + + elsif Has_Missing_Return (Spec_Id) then + declare + Hloc : constant Source_Ptr := Sloc (HSS); + Blok : constant Node_Id := + Make_Block_Statement (Hloc, + Handled_Statement_Sequence => HSS); + Rais : constant Node_Id := + Make_Raise_Program_Error (Hloc, + Reason => PE_Missing_Return); + + begin + Set_Handled_Statement_Sequence (N, + Make_Handled_Sequence_Of_Statements (Hloc, + Statements => New_List (Blok, Rais))); + + Push_Scope (Spec_Id); + Analyze (Blok); + Analyze (Rais); + Pop_Scope; + end; + end if; + + -- If subprogram contains a parameterless recursive call, then we may + -- have an infinite recursion, so see if we can generate code to check + -- for this possibility if storage checks are not suppressed. + + if Ekind (Spec_Id) = E_Procedure + and then Has_Recursive_Call (Spec_Id) + and then not Storage_Checks_Suppressed (Spec_Id) + then + Detect_Infinite_Recursion (N, Spec_Id); + end if; + + -- Set to encode entity names in package body before gigi is called + + Qualify_Entity_Names (N); + + -- If the body belongs to a nonabstract library-level source primitive + -- of a tagged type, install an elaboration check which ensures that a + -- dispatching call targeting the primitive will not execute the body + -- without it being previously elaborated. + + Install_Primitive_Elaboration_Check (N); + end Expand_N_Subprogram_Body; + + ----------------------------------- + -- Expand_N_Subprogram_Body_Stub -- + ----------------------------------- + + procedure Expand_N_Subprogram_Body_Stub (N : Node_Id) is + Bod : Node_Id; + + begin + if Present (Corresponding_Body (N)) then + Bod := Unit_Declaration_Node (Corresponding_Body (N)); + + -- The body may have been expanded already when it is analyzed + -- through the subunit node. Do no expand again: it interferes + -- with the construction of unnesting tables when generating C. + + if not Analyzed (Bod) then + Expand_N_Subprogram_Body (Bod); + end if; + + -- Add full qualification to entities that may be created late + -- during unnesting. + + Qualify_Entity_Names (N); + end if; + end Expand_N_Subprogram_Body_Stub; + + ------------------------------------- + -- Expand_N_Subprogram_Declaration -- + ------------------------------------- + + -- If the declaration appears within a protected body, it is a private + -- operation of the protected type. We must create the corresponding + -- protected subprogram an associated formals. For a normal protected + -- operation, this is done when expanding the protected type declaration. + + -- If the declaration is for a null procedure, emit null body + + procedure Expand_N_Subprogram_Declaration (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Subp : constant Entity_Id := Defining_Entity (N); + + -- Local variables + + Scop : constant Entity_Id := Scope (Subp); + Prot_Bod : Node_Id; + Prot_Decl : Node_Id; + Prot_Id : Entity_Id; + + -- Start of processing for Expand_N_Subprogram_Declaration + + begin + -- In SPARK, subprogram declarations are only allowed in package + -- specifications. + + if Nkind (Parent (N)) /= N_Package_Specification then + if Nkind (Parent (N)) = N_Compilation_Unit then + Check_SPARK_05_Restriction + ("subprogram declaration is not a library item", N); + + elsif Present (Next (N)) + and then Nkind (Next (N)) = N_Pragma + and then Get_Pragma_Id (Next (N)) = Pragma_Import + then + -- In SPARK, subprogram declarations are also permitted in + -- declarative parts when immediately followed by a corresponding + -- pragma Import. We only check here that there is some pragma + -- Import. + + null; + else + Check_SPARK_05_Restriction + ("subprogram declaration is not allowed here", N); + end if; + end if; + + -- Deal with case of protected subprogram. Do not generate protected + -- operation if operation is flagged as eliminated. + + if Is_List_Member (N) + and then Present (Parent (List_Containing (N))) + and then Nkind (Parent (List_Containing (N))) = N_Protected_Body + and then Is_Protected_Type (Scop) + then + if No (Protected_Body_Subprogram (Subp)) + and then not Is_Eliminated (Subp) + then + Prot_Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Build_Protected_Sub_Specification + (N, Scop, Unprotected_Mode)); + + -- The protected subprogram is declared outside of the protected + -- body. Given that the body has frozen all entities so far, we + -- analyze the subprogram and perform freezing actions explicitly. + -- including the generation of an explicit freeze node, to ensure + -- that gigi has the proper order of elaboration. + -- If the body is a subunit, the insertion point is before the + -- stub in the parent. + + Prot_Bod := Parent (List_Containing (N)); + + if Nkind (Parent (Prot_Bod)) = N_Subunit then + Prot_Bod := Corresponding_Stub (Parent (Prot_Bod)); + end if; + + Insert_Before (Prot_Bod, Prot_Decl); + Prot_Id := Defining_Unit_Name (Specification (Prot_Decl)); + Set_Has_Delayed_Freeze (Prot_Id); + + Push_Scope (Scope (Scop)); + Analyze (Prot_Decl); + Freeze_Before (N, Prot_Id); + Set_Protected_Body_Subprogram (Subp, Prot_Id); + + -- Create protected operation as well. Even though the operation + -- is only accessible within the body, it is possible to make it + -- available outside of the protected object by using 'Access to + -- provide a callback, so build protected version in all cases. + + Prot_Decl := + Make_Subprogram_Declaration (Loc, + Specification => + Build_Protected_Sub_Specification (N, Scop, Protected_Mode)); + Insert_Before (Prot_Bod, Prot_Decl); + Analyze (Prot_Decl); + + Pop_Scope; + end if; + + -- Ada 2005 (AI-348): Generate body for a null procedure. In most + -- cases this is superfluous because calls to it will be automatically + -- inlined, but we definitely need the body if preconditions for the + -- procedure are present, or if performing coverage analysis. + + elsif Nkind (Specification (N)) = N_Procedure_Specification + and then Null_Present (Specification (N)) + then + declare + Bod : constant Node_Id := Body_To_Inline (N); + + begin + Set_Has_Completion (Subp, False); + Append_Freeze_Action (Subp, Bod); + + -- The body now contains raise statements, so calls to it will + -- not be inlined. + + Set_Is_Inlined (Subp, False); + end; + end if; + + -- When generating C code, transform a function that returns a + -- constrained array type into a procedure with an out parameter + -- that carries the return value. + + -- We skip this transformation for unchecked conversions, since they + -- are not needed by the C generator (and this also produces cleaner + -- output). + + if Modify_Tree_For_C + and then Nkind (Specification (N)) = N_Function_Specification + and then Is_Array_Type (Etype (Subp)) + and then Is_Constrained (Etype (Subp)) + and then not Is_Unchecked_Conversion_Instance (Subp) + then + Build_Procedure_Form (N); + end if; + end Expand_N_Subprogram_Declaration; + + -------------------------------- + -- Expand_Non_Function_Return -- + -------------------------------- + + procedure Expand_Non_Function_Return (N : Node_Id) is + pragma Assert (No (Expression (N))); + + Loc : constant Source_Ptr := Sloc (N); + Scope_Id : Entity_Id := Return_Applies_To (Return_Statement_Entity (N)); + Kind : constant Entity_Kind := Ekind (Scope_Id); + Call : Node_Id; + Acc_Stat : Node_Id; + Goto_Stat : Node_Id; + Lab_Node : Node_Id; + + begin + -- Call the _Postconditions procedure if the related subprogram has + -- contract assertions that need to be verified on exit. + + if Ekind_In (Scope_Id, E_Entry, E_Entry_Family, E_Procedure) + and then Present (Postconditions_Proc (Scope_Id)) + then + Insert_Action (N, + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Postconditions_Proc (Scope_Id), Loc))); + end if; + + -- If it is a return from a procedure do no extra steps + + if Kind = E_Procedure or else Kind = E_Generic_Procedure then + return; + + -- If it is a nested return within an extended one, replace it with a + -- return of the previously declared return object. + + elsif Kind = E_Return_Statement then + Rewrite (N, + Make_Simple_Return_Statement (Loc, + Expression => + New_Occurrence_Of (First_Entity (Scope_Id), Loc))); + Set_Comes_From_Extended_Return_Statement (N); + Set_Return_Statement_Entity (N, Scope_Id); + Expand_Simple_Function_Return (N); + return; + end if; + + pragma Assert (Is_Entry (Scope_Id)); + + -- Look at the enclosing block to see whether the return is from an + -- accept statement or an entry body. + + for J in reverse 0 .. Scope_Stack.Last loop + Scope_Id := Scope_Stack.Table (J).Entity; + exit when Is_Concurrent_Type (Scope_Id); + end loop; + + -- If it is a return from accept statement it is expanded as call to + -- RTS Complete_Rendezvous and a goto to the end of the accept body. + + -- (cf : Expand_N_Accept_Statement, Expand_N_Selective_Accept, + -- Expand_N_Accept_Alternative in exp_ch9.adb) + + if Is_Task_Type (Scope_Id) then + + Call := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (RTE (RE_Complete_Rendezvous), Loc)); + Insert_Before (N, Call); + -- why not insert actions here??? + Analyze (Call); + + Acc_Stat := Parent (N); + while Nkind (Acc_Stat) /= N_Accept_Statement loop + Acc_Stat := Parent (Acc_Stat); + end loop; + + Lab_Node := Last (Statements + (Handled_Statement_Sequence (Acc_Stat))); + + Goto_Stat := Make_Goto_Statement (Loc, + Name => New_Occurrence_Of + (Entity (Identifier (Lab_Node)), Loc)); + + Set_Analyzed (Goto_Stat); + + Rewrite (N, Goto_Stat); + Analyze (N); + + -- If it is a return from an entry body, put a Complete_Entry_Body call + -- in front of the return. + + elsif Is_Protected_Type (Scope_Id) then + Call := + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (RTE (RE_Complete_Entry_Body), Loc), + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of + (Find_Protection_Object (Current_Scope), Loc), + Attribute_Name => Name_Unchecked_Access))); + + Insert_Before (N, Call); + Analyze (Call); + end if; + end Expand_Non_Function_Return; + + --------------------------------------- + -- Expand_Protected_Object_Reference -- + --------------------------------------- + + function Expand_Protected_Object_Reference + (N : Node_Id; + Scop : Entity_Id) return Node_Id + is + Loc : constant Source_Ptr := Sloc (N); + Corr : Entity_Id; + Rec : Node_Id; + Param : Entity_Id; + Proc : Entity_Id; + + begin + Rec := Make_Identifier (Loc, Name_uObject); + Set_Etype (Rec, Corresponding_Record_Type (Scop)); + + -- Find enclosing protected operation, and retrieve its first parameter, + -- which denotes the enclosing protected object. If the enclosing + -- operation is an entry, we are immediately within the protected body, + -- and we can retrieve the object from the service entries procedure. A + -- barrier function has the same signature as an entry. A barrier + -- function is compiled within the protected object, but unlike + -- protected operations its never needs locks, so that its protected + -- body subprogram points to itself. + + Proc := Current_Scope; + while Present (Proc) + and then Scope (Proc) /= Scop + loop + Proc := Scope (Proc); + end loop; + + Corr := Protected_Body_Subprogram (Proc); + + if No (Corr) then + + -- Previous error left expansion incomplete. + -- Nothing to do on this call. + + return Empty; + end if; + + Param := + Defining_Identifier + (First (Parameter_Specifications (Parent (Corr)))); + + if Is_Subprogram (Proc) and then Proc /= Corr then + + -- Protected function or procedure + + Set_Entity (Rec, Param); + + -- Rec is a reference to an entity which will not be in scope when + -- the call is reanalyzed, and needs no further analysis. + + Set_Analyzed (Rec); + + else + -- Entry or barrier function for entry body. The first parameter of + -- the entry body procedure is pointer to the object. We create a + -- local variable of the proper type, duplicating what is done to + -- define _object later on. + + declare + Decls : List_Id; + Obj_Ptr : constant Entity_Id := Make_Temporary (Loc, 'T'); + + begin + Decls := New_List ( + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Obj_Ptr, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + Subtype_Indication => + New_Occurrence_Of + (Corresponding_Record_Type (Scop), Loc)))); + + Insert_Actions (N, Decls); + Freeze_Before (N, Obj_Ptr); + + Rec := + Make_Explicit_Dereference (Loc, + Prefix => + Unchecked_Convert_To (Obj_Ptr, + New_Occurrence_Of (Param, Loc))); + + -- Analyze new actual. Other actuals in calls are already analyzed + -- and the list of actuals is not reanalyzed after rewriting. + + Set_Parent (Rec, N); + Analyze (Rec); + end; + end if; + + return Rec; + end Expand_Protected_Object_Reference; + + -------------------------------------- + -- Expand_Protected_Subprogram_Call -- + -------------------------------------- + + procedure Expand_Protected_Subprogram_Call + (N : Node_Id; + Subp : Entity_Id; + Scop : Entity_Id) + is + Rec : Node_Id; + + procedure Expand_Internal_Init_Call; + -- A call to an operation of the type may occur in the initialization + -- of a private component. In that case the prefix of the call is an + -- entity name and the call is treated as internal even though it + -- appears in code outside of the protected type. + + procedure Freeze_Called_Function; + -- If it is a function call it can appear in elaboration code and + -- the called entity must be frozen before the call. This must be + -- done before the call is expanded, as the expansion may rewrite it + -- to something other than a call (e.g. a temporary initialized in a + -- transient block). + + ------------------------------- + -- Expand_Internal_Init_Call -- + ------------------------------- + + procedure Expand_Internal_Init_Call is + begin + -- If the context is a protected object (rather than a protected + -- type) the call itself is bound to raise program_error because + -- the protected body will not have been elaborated yet. This is + -- diagnosed subsequently in Sem_Elab. + + Freeze_Called_Function; + + -- The target of the internal call is the first formal of the + -- enclosing initialization procedure. + + Rec := New_Occurrence_Of (First_Formal (Current_Scope), Sloc (N)); + Build_Protected_Subprogram_Call (N, + Name => Name (N), + Rec => Rec, + External => False); + Analyze (N); + Resolve (N, Etype (Subp)); + end Expand_Internal_Init_Call; + + ---------------------------- + -- Freeze_Called_Function -- + ---------------------------- + + procedure Freeze_Called_Function is + begin + if Ekind (Subp) = E_Function then + Freeze_Expression (Name (N)); + end if; + end Freeze_Called_Function; + + -- Start of processing for Expand_Protected_Subprogram_Call + + begin + -- If the protected object is not an enclosing scope, this is an inter- + -- object function call. Inter-object procedure calls are expanded by + -- Exp_Ch9.Build_Simple_Entry_Call. The call is intra-object only if the + -- subprogram being called is in the protected body being compiled, and + -- if the protected object in the call is statically the enclosing type. + -- The object may be a component of some other data structure, in which + -- case this must be handled as an inter-object call. + + if not In_Open_Scopes (Scop) + or else Is_Entry_Wrapper (Current_Scope) + or else not Is_Entity_Name (Name (N)) + then + if Nkind (Name (N)) = N_Selected_Component then + Rec := Prefix (Name (N)); + + elsif Nkind (Name (N)) = N_Indexed_Component then + Rec := Prefix (Prefix (Name (N))); + + -- If this is a call within an entry wrapper, it appears within a + -- precondition that calls another primitive of the synchronized + -- type. The target object of the call is the first actual on the + -- wrapper. Note that this is an external call, because the wrapper + -- is called outside of the synchronized object. This means that + -- an entry call to an entry with preconditions involves two + -- synchronized operations. + + elsif Ekind (Current_Scope) = E_Procedure + and then Is_Entry_Wrapper (Current_Scope) + then + Rec := New_Occurrence_Of (First_Entity (Current_Scope), Sloc (N)); + + else + -- If the context is the initialization procedure for a protected + -- type, the call is legal because the called entity must be a + -- function of that enclosing type, and this is treated as an + -- internal call. + + pragma Assert + (Is_Entity_Name (Name (N)) and then Inside_Init_Proc); + + Expand_Internal_Init_Call; + return; + end if; + + Freeze_Called_Function; + Build_Protected_Subprogram_Call (N, + Name => New_Occurrence_Of (Subp, Sloc (N)), + Rec => Convert_Concurrent (Rec, Etype (Rec)), + External => True); + + else + Rec := Expand_Protected_Object_Reference (N, Scop); + + if No (Rec) then + return; + end if; + + Freeze_Called_Function; + Build_Protected_Subprogram_Call (N, + Name => Name (N), + Rec => Rec, + External => False); + end if; + + -- Analyze and resolve the new call. The actuals have already been + -- resolved, but expansion of a function call will add extra actuals + -- if needed. Analysis of a procedure call already includes resolution. + + Analyze (N); + + if Ekind (Subp) = E_Function then + Resolve (N, Etype (Subp)); + end if; + end Expand_Protected_Subprogram_Call; + + ----------------------------------- + -- Expand_Simple_Function_Return -- + ----------------------------------- + + -- The "simple" comes from the syntax rule simple_return_statement. The + -- semantics are not at all simple. + + procedure Expand_Simple_Function_Return (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + + Scope_Id : constant Entity_Id := + Return_Applies_To (Return_Statement_Entity (N)); + -- The function we are returning from + + R_Type : constant Entity_Id := Etype (Scope_Id); + -- The result type of the function + + Utyp : constant Entity_Id := Underlying_Type (R_Type); + + Exp : Node_Id := Expression (N); + pragma Assert (Present (Exp)); + + Exptyp : constant Entity_Id := Etype (Exp); + -- The type of the expression (not necessarily the same as R_Type) + + Subtype_Ind : Node_Id; + -- If the result type of the function is class-wide and the expression + -- has a specific type, then we use the expression's type as the type of + -- the return object. In cases where the expression is an aggregate that + -- is built in place, this avoids the need for an expensive conversion + -- of the return object to the specific type on assignments to the + -- individual components. + + begin + if Is_Class_Wide_Type (R_Type) + and then not Is_Class_Wide_Type (Exptyp) + and then Nkind (Exp) /= N_Type_Conversion + then + Subtype_Ind := New_Occurrence_Of (Exptyp, Loc); + else + Subtype_Ind := New_Occurrence_Of (R_Type, Loc); + + -- If the result type is class-wide and the expression is a view + -- conversion, the conversion plays no role in the expansion because + -- it does not modify the tag of the object. Remove the conversion + -- altogether to prevent tag overwriting. + + if Is_Class_Wide_Type (R_Type) + and then not Is_Class_Wide_Type (Exptyp) + and then Nkind (Exp) = N_Type_Conversion + then + Exp := Expression (Exp); + end if; + end if; + + -- For the case of a simple return that does not come from an + -- extended return, in the case of build-in-place, we rewrite + -- "return <expression>;" to be: + + -- return _anon_ : <return_subtype> := <expression> + + -- The expansion produced by Expand_N_Extended_Return_Statement will + -- contain simple return statements (for example, a block containing + -- simple return of the return object), which brings us back here with + -- Comes_From_Extended_Return_Statement set. The reason for the barrier + -- checking for a simple return that does not come from an extended + -- return is to avoid this infinite recursion. + + -- The reason for this design is that for Ada 2005 limited returns, we + -- need to reify the return object, so we can build it "in place", and + -- we need a block statement to hang finalization and tasking stuff. + + -- ??? In order to avoid disruption, we avoid translating to extended + -- return except in the cases where we really need to (Ada 2005 for + -- inherently limited). We might prefer to do this translation in all + -- cases (except perhaps for the case of Ada 95 inherently limited), + -- in order to fully exercise the Expand_N_Extended_Return_Statement + -- code. This would also allow us to do the build-in-place optimization + -- for efficiency even in cases where it is semantically not required. + + -- As before, we check the type of the return expression rather than the + -- return type of the function, because the latter may be a limited + -- class-wide interface type, which is not a limited type, even though + -- the type of the expression may be. + + pragma Assert + (Comes_From_Extended_Return_Statement (N) + or else not Is_Build_In_Place_Function_Call (Exp) + or else Is_Build_In_Place_Function (Scope_Id)); + + if not Comes_From_Extended_Return_Statement (N) + and then Is_Build_In_Place_Function (Scope_Id) + and then not Debug_Flag_Dot_L + + -- The functionality of interface thunks is simple and it is always + -- handled by means of simple return statements. This leaves their + -- expansion simple and clean. + + and then not Is_Thunk (Current_Scope) + then + declare + Return_Object_Entity : constant Entity_Id := + Make_Temporary (Loc, 'R', Exp); + + Obj_Decl : constant Node_Id := + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Object_Entity, + Object_Definition => Subtype_Ind, + Expression => Exp); + + Ext : constant Node_Id := + Make_Extended_Return_Statement (Loc, + Return_Object_Declarations => New_List (Obj_Decl)); + -- Do not perform this high-level optimization if the result type + -- is an interface because the "this" pointer must be displaced. + + begin + Rewrite (N, Ext); + Analyze (N); + return; + end; + end if; + + -- Here we have a simple return statement that is part of the expansion + -- of an extended return statement (either written by the user, or + -- generated by the above code). + + -- Always normalize C/Fortran boolean result. This is not always needed, + -- but it seems a good idea to minimize the passing around of non- + -- normalized values, and in any case this handles the processing of + -- barrier functions for protected types, which turn the condition into + -- a return statement. + + if Is_Boolean_Type (Exptyp) + and then Nonzero_Is_True (Exptyp) + then + Adjust_Condition (Exp); + Adjust_Result_Type (Exp, Exptyp); + end if; + + -- Do validity check if enabled for returns + + if Validity_Checks_On + and then Validity_Check_Returns + then + Ensure_Valid (Exp); + end if; + + -- Check the result expression of a scalar function against the subtype + -- of the function by inserting a conversion. This conversion must + -- eventually be performed for other classes of types, but for now it's + -- only done for scalars. + -- ??? + + if Is_Scalar_Type (Exptyp) then + Rewrite (Exp, Convert_To (R_Type, Exp)); + + -- The expression is resolved to ensure that the conversion gets + -- expanded to generate a possible constraint check. + + Analyze_And_Resolve (Exp, R_Type); + end if; + + -- Deal with returning variable length objects and controlled types + + -- Nothing to do if we are returning by reference, or this is not a + -- type that requires special processing (indicated by the fact that + -- it requires a cleanup scope for the secondary stack case). + + if Is_Build_In_Place_Function (Scope_Id) + or else Is_Limited_Interface (Exptyp) + then + null; + + -- No copy needed for thunks returning interface type objects since + -- the object is returned by reference and the maximum functionality + -- required is just to displace the pointer. + + elsif Is_Thunk (Current_Scope) and then Is_Interface (Exptyp) then + null; + + -- If the call is within a thunk and the type is a limited view, the + -- backend will eventually see the non-limited view of the type. + + elsif Is_Thunk (Current_Scope) and then Is_Incomplete_Type (Exptyp) then + return; + + elsif not Requires_Transient_Scope (R_Type) then + + -- Mutable records with variable-length components are not returned + -- on the sec-stack, so we need to make sure that the back end will + -- only copy back the size of the actual value, and not the maximum + -- size. We create an actual subtype for this purpose. However we + -- need not do it if the expression is a function call since this + -- will be done in the called function and doing it here too would + -- cause a temporary with maximum size to be created. + + declare + Ubt : constant Entity_Id := Underlying_Type (Base_Type (Exptyp)); + Decl : Node_Id; + Ent : Entity_Id; + begin + if Nkind (Exp) /= N_Function_Call + and then Has_Discriminants (Ubt) + and then not Is_Constrained (Ubt) + and then not Has_Unchecked_Union (Ubt) + then + Decl := Build_Actual_Subtype (Ubt, Exp); + Ent := Defining_Identifier (Decl); + Insert_Action (Exp, Decl); + Rewrite (Exp, Unchecked_Convert_To (Ent, Exp)); + Analyze_And_Resolve (Exp); + end if; + end; + + -- Here if secondary stack is used + + else + -- Prevent the reclamation of the secondary stack by all enclosing + -- blocks and loops as well as the related function; otherwise the + -- result would be reclaimed too early. + + Set_Enclosing_Sec_Stack_Return (N); + + -- Optimize the case where the result is a function call. In this + -- case either the result is already on the secondary stack, or is + -- already being returned with the stack pointer depressed and no + -- further processing is required except to set the By_Ref flag + -- to ensure that gigi does not attempt an extra unnecessary copy. + -- (actually not just unnecessary but harmfully wrong in the case + -- of a controlled type, where gigi does not know how to do a copy). + -- To make up for a gcc 2.8.1 deficiency (???), we perform the copy + -- for array types if the constrained status of the target type is + -- different from that of the expression. + + if Requires_Transient_Scope (Exptyp) + and then + (not Is_Array_Type (Exptyp) + or else Is_Constrained (Exptyp) = Is_Constrained (R_Type) + or else CW_Or_Has_Controlled_Part (Utyp)) + and then Nkind (Exp) = N_Function_Call + then + Set_By_Ref (N); + + -- Remove side effects from the expression now so that other parts + -- of the expander do not have to reanalyze this node without this + -- optimization + + Rewrite (Exp, Duplicate_Subexpr_No_Checks (Exp)); + + -- Ada 2005 (AI-251): If the type of the returned object is + -- an interface then add an implicit type conversion to force + -- displacement of the "this" pointer. + + if Is_Interface (R_Type) then + Rewrite (Exp, Convert_To (R_Type, Relocate_Node (Exp))); + end if; + + Analyze_And_Resolve (Exp, R_Type); + + -- For controlled types, do the allocation on the secondary stack + -- manually in order to call adjust at the right time: + + -- type Anon1 is access R_Type; + -- for Anon1'Storage_pool use ss_pool; + -- Anon2 : anon1 := new R_Type'(expr); + -- return Anon2.all; + + -- We do the same for classwide types that are not potentially + -- controlled (by the virtue of restriction No_Finalization) because + -- gigi is not able to properly allocate class-wide types. + + elsif CW_Or_Has_Controlled_Part (Utyp) then + declare + Loc : constant Source_Ptr := Sloc (N); + Acc_Typ : constant Entity_Id := Make_Temporary (Loc, 'A'); + Alloc_Node : Node_Id; + Temp : Entity_Id; + + begin + Set_Ekind (Acc_Typ, E_Access_Type); + + Set_Associated_Storage_Pool (Acc_Typ, RTE (RE_SS_Pool)); + + -- This is an allocator for the secondary stack, and it's fine + -- to have Comes_From_Source set False on it, as gigi knows not + -- to flag it as a violation of No_Implicit_Heap_Allocations. + + Alloc_Node := + Make_Allocator (Loc, + Expression => + Make_Qualified_Expression (Loc, + Subtype_Mark => New_Occurrence_Of (Etype (Exp), Loc), + Expression => Relocate_Node (Exp))); + + -- We do not want discriminant checks on the declaration, + -- given that it gets its value from the allocator. + + Set_No_Initialization (Alloc_Node); + + Temp := Make_Temporary (Loc, 'R', Alloc_Node); + + Insert_List_Before_And_Analyze (N, New_List ( + Make_Full_Type_Declaration (Loc, + Defining_Identifier => Acc_Typ, + Type_Definition => + Make_Access_To_Object_Definition (Loc, + Subtype_Indication => Subtype_Ind)), + + Make_Object_Declaration (Loc, + Defining_Identifier => Temp, + Object_Definition => New_Occurrence_Of (Acc_Typ, Loc), + Expression => Alloc_Node))); + + Rewrite (Exp, + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Temp, Loc))); + + -- Ada 2005 (AI-251): If the type of the returned object is + -- an interface then add an implicit type conversion to force + -- displacement of the "this" pointer. + + if Is_Interface (R_Type) then + Rewrite (Exp, Convert_To (R_Type, Relocate_Node (Exp))); + end if; + + Analyze_And_Resolve (Exp, R_Type); + end; + + -- Otherwise use the gigi mechanism to allocate result on the + -- secondary stack. + + else + Check_Restriction (No_Secondary_Stack, N); + Set_Storage_Pool (N, RTE (RE_SS_Pool)); + Set_Procedure_To_Call (N, RTE (RE_SS_Allocate)); + end if; + end if; + + -- Implement the rules of 6.5(8-10), which require a tag check in + -- the case of a limited tagged return type, and tag reassignment for + -- nonlimited tagged results. These actions are needed when the return + -- type is a specific tagged type and the result expression is a + -- conversion or a formal parameter, because in that case the tag of + -- the expression might differ from the tag of the specific result type. + + if Is_Tagged_Type (Utyp) + and then not Is_Class_Wide_Type (Utyp) + and then (Nkind_In (Exp, N_Type_Conversion, + N_Unchecked_Type_Conversion) + or else (Is_Entity_Name (Exp) + and then Ekind (Entity (Exp)) in Formal_Kind)) + then + -- When the return type is limited, perform a check that the tag of + -- the result is the same as the tag of the return type. + + if Is_Limited_Type (R_Type) then + Insert_Action (Exp, + Make_Raise_Constraint_Error (Loc, + Condition => + Make_Op_Ne (Loc, + Left_Opnd => + Make_Selected_Component (Loc, + Prefix => Duplicate_Subexpr (Exp), + Selector_Name => Make_Identifier (Loc, Name_uTag)), + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (Base_Type (Utyp), Loc), + Attribute_Name => Name_Tag)), + Reason => CE_Tag_Check_Failed)); + + -- If the result type is a specific nonlimited tagged type, then we + -- have to ensure that the tag of the result is that of the result + -- type. This is handled by making a copy of the expression in + -- the case where it might have a different tag, namely when the + -- expression is a conversion or a formal parameter. We create a new + -- object of the result type and initialize it from the expression, + -- which will implicitly force the tag to be set appropriately. + + else + declare + ExpR : constant Node_Id := Relocate_Node (Exp); + Result_Id : constant Entity_Id := + Make_Temporary (Loc, 'R', ExpR); + Result_Exp : constant Node_Id := + New_Occurrence_Of (Result_Id, Loc); + Result_Obj : constant Node_Id := + Make_Object_Declaration (Loc, + Defining_Identifier => Result_Id, + Object_Definition => + New_Occurrence_Of (R_Type, Loc), + Constant_Present => True, + Expression => ExpR); + + begin + Set_Assignment_OK (Result_Obj); + Insert_Action (Exp, Result_Obj); + + Rewrite (Exp, Result_Exp); + Analyze_And_Resolve (Exp, R_Type); + end; + end if; + + -- Ada 2005 (AI-344): If the result type is class-wide, then insert + -- a check that the level of the return expression's underlying type + -- is not deeper than the level of the master enclosing the function. + -- Always generate the check when the type of the return expression + -- is class-wide, when it's a type conversion, or when it's a formal + -- parameter. Otherwise, suppress the check in the case where the + -- return expression has a specific type whose level is known not to + -- be statically deeper than the function's result type. + + -- No runtime check needed in interface thunks since it is performed + -- by the target primitive associated with the thunk. + + -- Note: accessibility check is skipped in the VM case, since there + -- does not seem to be any practical way to implement this check. + + elsif Ada_Version >= Ada_2005 + and then Tagged_Type_Expansion + and then Is_Class_Wide_Type (R_Type) + and then not Is_Thunk (Current_Scope) + and then not Scope_Suppress.Suppress (Accessibility_Check) + and then + (Is_Class_Wide_Type (Etype (Exp)) + or else Nkind_In (Exp, N_Type_Conversion, + N_Unchecked_Type_Conversion) + or else (Is_Entity_Name (Exp) + and then Ekind (Entity (Exp)) in Formal_Kind) + or else Scope_Depth (Enclosing_Dynamic_Scope (Etype (Exp))) > + Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id))) + then + declare + Tag_Node : Node_Id; + + begin + -- Ada 2005 (AI-251): In class-wide interface objects we displace + -- "this" to reference the base of the object. This is required to + -- get access to the TSD of the object. + + if Is_Class_Wide_Type (Etype (Exp)) + and then Is_Interface (Etype (Exp)) + then + -- If the expression is an explicit dereference then we can + -- directly displace the pointer to reference the base of + -- the object. + + if Nkind (Exp) = N_Explicit_Dereference then + Tag_Node := + Make_Explicit_Dereference (Loc, + Prefix => + Unchecked_Convert_To (RTE (RE_Tag_Ptr), + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Base_Address), Loc), + Parameter_Associations => New_List ( + Unchecked_Convert_To (RTE (RE_Address), + Duplicate_Subexpr (Prefix (Exp))))))); + + -- Similar case to the previous one but the expression is a + -- renaming of an explicit dereference. + + elsif Nkind (Exp) = N_Identifier + and then Present (Renamed_Object (Entity (Exp))) + and then Nkind (Renamed_Object (Entity (Exp))) + = N_Explicit_Dereference + then + Tag_Node := + Make_Explicit_Dereference (Loc, + Prefix => + Unchecked_Convert_To (RTE (RE_Tag_Ptr), + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Base_Address), Loc), + Parameter_Associations => New_List ( + Unchecked_Convert_To (RTE (RE_Address), + Duplicate_Subexpr + (Prefix + (Renamed_Object (Entity (Exp))))))))); + + -- Common case: obtain the address of the actual object and + -- displace the pointer to reference the base of the object. + + else + Tag_Node := + Make_Explicit_Dereference (Loc, + Prefix => + Unchecked_Convert_To (RTE (RE_Tag_Ptr), + Make_Function_Call (Loc, + Name => + New_Occurrence_Of (RTE (RE_Base_Address), Loc), + Parameter_Associations => New_List ( + Make_Attribute_Reference (Loc, + Prefix => Duplicate_Subexpr (Exp), + Attribute_Name => Name_Address))))); + end if; + else + Tag_Node := + Make_Attribute_Reference (Loc, + Prefix => Duplicate_Subexpr (Exp), + Attribute_Name => Name_Tag); + end if; + + -- CodePeer does not do anything useful with + -- Ada.Tags.Type_Specific_Data components. + + if not CodePeer_Mode then + Insert_Action (Exp, + Make_Raise_Program_Error (Loc, + Condition => + Make_Op_Gt (Loc, + Left_Opnd => Build_Get_Access_Level (Loc, Tag_Node), + Right_Opnd => + Make_Integer_Literal (Loc, + Scope_Depth (Enclosing_Dynamic_Scope (Scope_Id)))), + Reason => PE_Accessibility_Check_Failed)); + end if; + end; + + -- AI05-0073: If function has a controlling access result, check that + -- the tag of the return value, if it is not null, matches designated + -- type of return type. + + -- The return expression is referenced twice in the code below, so it + -- must be made free of side effects. Given that different compilers + -- may evaluate these parameters in different order, both occurrences + -- perform a copy. + + elsif Ekind (R_Type) = E_Anonymous_Access_Type + and then Has_Controlling_Result (Scope_Id) + then + Insert_Action (N, + Make_Raise_Constraint_Error (Loc, + Condition => + Make_And_Then (Loc, + Left_Opnd => + Make_Op_Ne (Loc, + Left_Opnd => Duplicate_Subexpr (Exp), + Right_Opnd => Make_Null (Loc)), + + Right_Opnd => Make_Op_Ne (Loc, + Left_Opnd => + Make_Selected_Component (Loc, + Prefix => Duplicate_Subexpr (Exp), + Selector_Name => Make_Identifier (Loc, Name_uTag)), + + Right_Opnd => + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (Designated_Type (R_Type), Loc), + Attribute_Name => Name_Tag))), + + Reason => CE_Tag_Check_Failed), + Suppress => All_Checks); + end if; + + -- AI05-0234: RM 6.5(21/3). Check access discriminants to + -- ensure that the function result does not outlive an + -- object designated by one of it discriminants. + + if Present (Extra_Accessibility_Of_Result (Scope_Id)) + and then Has_Unconstrained_Access_Discriminants (R_Type) + then + declare + Discrim_Source : Node_Id; + + procedure Check_Against_Result_Level (Level : Node_Id); + -- Check the given accessibility level against the level + -- determined by the point of call. (AI05-0234). + + -------------------------------- + -- Check_Against_Result_Level -- + -------------------------------- + + procedure Check_Against_Result_Level (Level : Node_Id) is + begin + Insert_Action (N, + Make_Raise_Program_Error (Loc, + Condition => + Make_Op_Gt (Loc, + Left_Opnd => Level, + Right_Opnd => + New_Occurrence_Of + (Extra_Accessibility_Of_Result (Scope_Id), Loc)), + Reason => PE_Accessibility_Check_Failed)); + end Check_Against_Result_Level; + + begin + Discrim_Source := Exp; + while Nkind (Discrim_Source) = N_Qualified_Expression loop + Discrim_Source := Expression (Discrim_Source); + end loop; + + if Nkind (Discrim_Source) = N_Identifier + and then Is_Return_Object (Entity (Discrim_Source)) + then + Discrim_Source := Entity (Discrim_Source); + + if Is_Constrained (Etype (Discrim_Source)) then + Discrim_Source := Etype (Discrim_Source); + else + Discrim_Source := Expression (Parent (Discrim_Source)); + end if; + + elsif Nkind (Discrim_Source) = N_Identifier + and then Nkind_In (Original_Node (Discrim_Source), + N_Aggregate, N_Extension_Aggregate) + then + Discrim_Source := Original_Node (Discrim_Source); + + elsif Nkind (Discrim_Source) = N_Explicit_Dereference and then + Nkind (Original_Node (Discrim_Source)) = N_Function_Call + then + Discrim_Source := Original_Node (Discrim_Source); + end if; + + Discrim_Source := Unqual_Conv (Discrim_Source); + + case Nkind (Discrim_Source) is + when N_Defining_Identifier => + pragma Assert (Is_Composite_Type (Discrim_Source) + and then Has_Discriminants (Discrim_Source) + and then Is_Constrained (Discrim_Source)); + + declare + Discrim : Entity_Id := + First_Discriminant (Base_Type (R_Type)); + Disc_Elmt : Elmt_Id := + First_Elmt (Discriminant_Constraint + (Discrim_Source)); + begin + loop + if Ekind (Etype (Discrim)) = + E_Anonymous_Access_Type + then + Check_Against_Result_Level + (Dynamic_Accessibility_Level (Node (Disc_Elmt))); + end if; + + Next_Elmt (Disc_Elmt); + Next_Discriminant (Discrim); + exit when not Present (Discrim); + end loop; + end; + + when N_Aggregate + | N_Extension_Aggregate + => + -- Unimplemented: extension aggregate case where discrims + -- come from ancestor part, not extension part. + + declare + Discrim : Entity_Id := + First_Discriminant (Base_Type (R_Type)); + + Disc_Exp : Node_Id := Empty; + + Positionals_Exhausted + : Boolean := not Present (Expressions + (Discrim_Source)); + + function Associated_Expr + (Comp_Id : Entity_Id; + Associations : List_Id) return Node_Id; + + -- Given a component and a component associations list, + -- locate the expression for that component; returns + -- Empty if no such expression is found. + + --------------------- + -- Associated_Expr -- + --------------------- + + function Associated_Expr + (Comp_Id : Entity_Id; + Associations : List_Id) return Node_Id + is + Assoc : Node_Id; + Choice : Node_Id; + + begin + -- Simple linear search seems ok here + + Assoc := First (Associations); + while Present (Assoc) loop + Choice := First (Choices (Assoc)); + while Present (Choice) loop + if (Nkind (Choice) = N_Identifier + and then Chars (Choice) = Chars (Comp_Id)) + or else (Nkind (Choice) = N_Others_Choice) + then + return Expression (Assoc); + end if; + + Next (Choice); + end loop; + + Next (Assoc); + end loop; + + return Empty; + end Associated_Expr; + + -- Start of processing for Expand_Simple_Function_Return + + begin + if not Positionals_Exhausted then + Disc_Exp := First (Expressions (Discrim_Source)); + end if; + + loop + if Positionals_Exhausted then + Disc_Exp := + Associated_Expr + (Discrim, + Component_Associations (Discrim_Source)); + end if; + + if Ekind (Etype (Discrim)) = + E_Anonymous_Access_Type + then + Check_Against_Result_Level + (Dynamic_Accessibility_Level (Disc_Exp)); + end if; + + Next_Discriminant (Discrim); + exit when not Present (Discrim); + + if not Positionals_Exhausted then + Next (Disc_Exp); + Positionals_Exhausted := not Present (Disc_Exp); + end if; + end loop; + end; + + when N_Function_Call => + + -- No check needed (check performed by callee) + + null; + + when others => + declare + Level : constant Node_Id := + Make_Integer_Literal (Loc, + Object_Access_Level (Discrim_Source)); + + begin + -- Unimplemented: check for name prefix that includes + -- a dereference of an access value with a dynamic + -- accessibility level (e.g., an access param or a + -- saooaaat) and use dynamic level in that case. For + -- example: + -- return Access_Param.all(Some_Index).Some_Component; + -- ??? + + Set_Etype (Level, Standard_Natural); + Check_Against_Result_Level (Level); + end; + end case; + end; + end if; + + -- If we are returning an object that may not be bit-aligned, then copy + -- the value into a temporary first. This copy may need to expand to a + -- loop of component operations. + + if Is_Possibly_Unaligned_Slice (Exp) + or else Is_Possibly_Unaligned_Object (Exp) + then + declare + ExpR : constant Node_Id := Relocate_Node (Exp); + Tnn : constant Entity_Id := Make_Temporary (Loc, 'T', ExpR); + begin + Insert_Action (Exp, + Make_Object_Declaration (Loc, + Defining_Identifier => Tnn, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (R_Type, Loc), + Expression => ExpR), + Suppress => All_Checks); + Rewrite (Exp, New_Occurrence_Of (Tnn, Loc)); + end; + end if; + + -- Call the _Postconditions procedure if the related function has + -- contract assertions that need to be verified on exit. + + if Ekind (Scope_Id) = E_Function + and then Present (Postconditions_Proc (Scope_Id)) + then + -- In the case of discriminated objects, we have created a + -- constrained subtype above, and used the underlying type. This + -- transformation is post-analysis and harmless, except that now the + -- call to the post-condition will be analyzed and the type kinds + -- have to match. + + if Nkind (Exp) = N_Unchecked_Type_Conversion + and then Is_Private_Type (R_Type) /= Is_Private_Type (Etype (Exp)) + then + Rewrite (Exp, Expression (Relocate_Node (Exp))); + end if; + + -- We are going to reference the returned value twice in this case, + -- once in the call to _Postconditions, and once in the actual return + -- statement, but we can't have side effects happening twice. + + Force_Evaluation (Exp, Mode => Strict); + + -- Generate call to _Postconditions + + Insert_Action (Exp, + Make_Procedure_Call_Statement (Loc, + Name => + New_Occurrence_Of (Postconditions_Proc (Scope_Id), Loc), + Parameter_Associations => New_List (New_Copy_Tree (Exp)))); + end if; + + -- Ada 2005 (AI-251): If this return statement corresponds with an + -- simple return statement associated with an extended return statement + -- and the type of the returned object is an interface then generate an + -- implicit conversion to force displacement of the "this" pointer. + + if Ada_Version >= Ada_2005 + and then Comes_From_Extended_Return_Statement (N) + and then Nkind (Expression (N)) = N_Identifier + and then Is_Interface (Utyp) + and then Utyp /= Underlying_Type (Exptyp) + then + Rewrite (Exp, Convert_To (Utyp, Relocate_Node (Exp))); + Analyze_And_Resolve (Exp); + end if; + end Expand_Simple_Function_Return; + + -------------------------------------------- + -- Has_Unconstrained_Access_Discriminants -- + -------------------------------------------- + + function Has_Unconstrained_Access_Discriminants + (Subtyp : Entity_Id) return Boolean + is + Discr : Entity_Id; + + begin + if Has_Discriminants (Subtyp) + and then not Is_Constrained (Subtyp) + then + Discr := First_Discriminant (Subtyp); + while Present (Discr) loop + if Ekind (Etype (Discr)) = E_Anonymous_Access_Type then + return True; + end if; + + Next_Discriminant (Discr); + end loop; + end if; + + return False; + end Has_Unconstrained_Access_Discriminants; + + ----------------------------------- + -- Is_Build_In_Place_Result_Type -- + ----------------------------------- + + function Is_Build_In_Place_Result_Type (Typ : Entity_Id) return Boolean is + begin + if not Expander_Active then + return False; + end if; + + -- In Ada 2005 all functions with an inherently limited return type + -- must be handled using a build-in-place profile, including the case + -- of a function with a limited interface result, where the function + -- may return objects of nonlimited descendants. + + if Is_Limited_View (Typ) then + return Ada_Version >= Ada_2005 and then not Debug_Flag_Dot_L; + + else + if Debug_Flag_Dot_9 then + return False; + end if; + + if Has_Interfaces (Typ) then + return False; + end if; + + declare + T : Entity_Id := Typ; + begin + -- For T'Class, return True if it's True for T. This is necessary + -- because a class-wide function might say "return F (...)", where + -- F returns the corresponding specific type. We need a loop in + -- case T is a subtype of a class-wide type. + + while Is_Class_Wide_Type (T) loop + T := Etype (T); + end loop; + + -- If this is a generic formal type in an instance, return True if + -- it's True for the generic actual type. + + if Nkind (Parent (T)) = N_Subtype_Declaration + and then Present (Generic_Parent_Type (Parent (T))) + then + T := Entity (Subtype_Indication (Parent (T))); + + if Present (Full_View (T)) then + T := Full_View (T); + end if; + end if; + + if Present (Underlying_Type (T)) then + T := Underlying_Type (T); + end if; + + declare + Result : Boolean; + -- So we can stop here in the debugger + begin + -- ???For now, enable build-in-place for a very narrow set of + -- controlled types. Change "if True" to "if False" to + -- experiment more controlled types. Eventually, we would + -- like to enable build-in-place for all tagged types, all + -- types that need finalization, and all caller-unknown-size + -- types. + + if True then + Result := Is_Controlled (T) + and then Present (Enclosing_Subprogram (T)) + and then not Is_Compilation_Unit (Enclosing_Subprogram (T)) + and then Ekind (Enclosing_Subprogram (T)) = E_Procedure; + else + Result := Is_Controlled (T); + end if; + + return Result; + end; + end; + end if; + end Is_Build_In_Place_Result_Type; + + -------------------------------- + -- Is_Build_In_Place_Function -- + -------------------------------- + + function Is_Build_In_Place_Function (E : Entity_Id) return Boolean is + begin + -- This function is called from Expand_Subtype_From_Expr during + -- semantic analysis, even when expansion is off. In those cases + -- the build_in_place expansion will not take place. + + if not Expander_Active then + return False; + end if; + + -- For now we test whether E denotes a function or access-to-function + -- type whose result subtype is inherently limited. Later this test + -- may be revised to allow composite nonlimited types. Functions with + -- a foreign convention or whose result type has a foreign convention + -- never qualify. + + if Ekind_In (E, E_Function, E_Generic_Function) + or else (Ekind (E) = E_Subprogram_Type + and then Etype (E) /= Standard_Void_Type) + then + -- Note: If the function has a foreign convention, it cannot build + -- its result in place, so you're on your own. On the other hand, + -- if only the return type has a foreign convention, its layout is + -- intended to be compatible with the other language, but the build- + -- in place machinery can ensure that the object is not copied. + + return Is_Build_In_Place_Result_Type (Etype (E)) + and then not Has_Foreign_Convention (E) + and then not Debug_Flag_Dot_L; + + else + return False; + end if; + end Is_Build_In_Place_Function; + + ------------------------------------- + -- Is_Build_In_Place_Function_Call -- + ------------------------------------- + + function Is_Build_In_Place_Function_Call (N : Node_Id) return Boolean is + Exp_Node : constant Node_Id := Unqual_Conv (N); + Function_Id : Entity_Id; + + begin + -- Return False if the expander is currently inactive, since awareness + -- of build-in-place treatment is only relevant during expansion. Note + -- that Is_Build_In_Place_Function, which is called as part of this + -- function, is also conditioned this way, but we need to check here as + -- well to avoid blowing up on processing protected calls when expansion + -- is disabled (such as with -gnatc) since those would trip over the + -- raise of Program_Error below. + + -- In SPARK mode, build-in-place calls are not expanded, so that we + -- may end up with a call that is neither resolved to an entity, nor + -- an indirect call. + + if not Expander_Active or else Nkind (Exp_Node) /= N_Function_Call then + return False; + end if; + + if Is_Entity_Name (Name (Exp_Node)) then + Function_Id := Entity (Name (Exp_Node)); + + -- In the case of an explicitly dereferenced call, use the subprogram + -- type generated for the dereference. + + elsif Nkind (Name (Exp_Node)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Exp_Node)); + + -- This may be a call to a protected function. + + elsif Nkind (Name (Exp_Node)) = N_Selected_Component then + Function_Id := Etype (Entity (Selector_Name (Name (Exp_Node)))); + + else + raise Program_Error; + end if; + + declare + Result : constant Boolean := Is_Build_In_Place_Function (Function_Id); + -- So we can stop here in the debugger + begin + return Result; + end; + end Is_Build_In_Place_Function_Call; + + ----------------------- + -- Freeze_Subprogram -- + ----------------------- + + procedure Freeze_Subprogram (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + + procedure Register_Predefined_DT_Entry (Prim : Entity_Id); + -- (Ada 2005): Register a predefined primitive in all the secondary + -- dispatch tables of its primitive type. + + ---------------------------------- + -- Register_Predefined_DT_Entry -- + ---------------------------------- + + procedure Register_Predefined_DT_Entry (Prim : Entity_Id) is + Iface_DT_Ptr : Elmt_Id; + Tagged_Typ : Entity_Id; + Thunk_Id : Entity_Id; + Thunk_Code : Node_Id; + + begin + Tagged_Typ := Find_Dispatching_Type (Prim); + + if No (Access_Disp_Table (Tagged_Typ)) + or else not Has_Interfaces (Tagged_Typ) + or else not RTE_Available (RE_Interface_Tag) + or else Restriction_Active (No_Dispatching_Calls) + then + return; + end if; + + -- Skip the first two access-to-dispatch-table pointers since they + -- leads to the primary dispatch table (predefined DT and user + -- defined DT). We are only concerned with the secondary dispatch + -- table pointers. Note that the access-to- dispatch-table pointer + -- corresponds to the first implemented interface retrieved below. + + Iface_DT_Ptr := + Next_Elmt (Next_Elmt (First_Elmt (Access_Disp_Table (Tagged_Typ)))); + + while Present (Iface_DT_Ptr) + and then Ekind (Node (Iface_DT_Ptr)) = E_Constant + loop + pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); + Expand_Interface_Thunk (Prim, Thunk_Id, Thunk_Code); + + if Present (Thunk_Code) then + Insert_Actions_After (N, New_List ( + Thunk_Code, + + Build_Set_Predefined_Prim_Op_Address (Loc, + Tag_Node => + New_Occurrence_Of (Node (Next_Elmt (Iface_DT_Ptr)), Loc), + Position => DT_Position (Prim), + Address_Node => + Unchecked_Convert_To (RTE (RE_Prim_Ptr), + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Thunk_Id, Loc), + Attribute_Name => Name_Unrestricted_Access))), + + Build_Set_Predefined_Prim_Op_Address (Loc, + Tag_Node => + New_Occurrence_Of + (Node (Next_Elmt (Next_Elmt (Next_Elmt (Iface_DT_Ptr)))), + Loc), + Position => DT_Position (Prim), + Address_Node => + Unchecked_Convert_To (RTE (RE_Prim_Ptr), + Make_Attribute_Reference (Loc, + Prefix => New_Occurrence_Of (Prim, Loc), + Attribute_Name => Name_Unrestricted_Access))))); + end if; + + -- Skip the tag of the predefined primitives dispatch table + + Next_Elmt (Iface_DT_Ptr); + pragma Assert (Has_Thunks (Node (Iface_DT_Ptr))); + + -- Skip tag of the no-thunks dispatch table + + Next_Elmt (Iface_DT_Ptr); + pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); + + -- Skip tag of predefined primitives no-thunks dispatch table + + Next_Elmt (Iface_DT_Ptr); + pragma Assert (not Has_Thunks (Node (Iface_DT_Ptr))); + + Next_Elmt (Iface_DT_Ptr); + end loop; + end Register_Predefined_DT_Entry; + + -- Local variables + + Subp : constant Entity_Id := Entity (N); + + -- Start of processing for Freeze_Subprogram + + begin + -- We suppress the initialization of the dispatch table entry when + -- not Tagged_Type_Expansion because the dispatching mechanism is + -- handled internally by the target. + + if Is_Dispatching_Operation (Subp) + and then not Is_Abstract_Subprogram (Subp) + and then Present (DTC_Entity (Subp)) + and then Present (Scope (DTC_Entity (Subp))) + and then Tagged_Type_Expansion + and then not Restriction_Active (No_Dispatching_Calls) + and then RTE_Available (RE_Tag) + then + declare + Typ : constant Entity_Id := Scope (DTC_Entity (Subp)); + + begin + -- Handle private overridden primitives + + if not Is_CPP_Class (Typ) then + Check_Overriding_Operation (Subp); + end if; + + -- We assume that imported CPP primitives correspond with objects + -- whose constructor is in the CPP side; therefore we don't need + -- to generate code to register them in the dispatch table. + + if Is_CPP_Class (Typ) then + null; + + -- Handle CPP primitives found in derivations of CPP_Class types. + -- These primitives must have been inherited from some parent, and + -- there is no need to register them in the dispatch table because + -- Build_Inherit_Prims takes care of initializing these slots. + + elsif Is_Imported (Subp) + and then (Convention (Subp) = Convention_CPP + or else Convention (Subp) = Convention_C) + then + null; + + -- Generate code to register the primitive in non statically + -- allocated dispatch tables + + elsif not Building_Static_DT (Scope (DTC_Entity (Subp))) then + + -- When a primitive is frozen, enter its name in its dispatch + -- table slot. + + if not Is_Interface (Typ) + or else Present (Interface_Alias (Subp)) + then + if Is_Predefined_Dispatching_Operation (Subp) then + Register_Predefined_DT_Entry (Subp); + end if; + + Insert_Actions_After (N, + Register_Primitive (Loc, Prim => Subp)); + end if; + end if; + end; + end if; + + -- Mark functions that return by reference. Note that it cannot be part + -- of the normal semantic analysis of the spec since the underlying + -- returned type may not be known yet (for private types). + + declare + Typ : constant Entity_Id := Etype (Subp); + Utyp : constant Entity_Id := Underlying_Type (Typ); + + begin + if Is_Limited_View (Typ) then + Set_Returns_By_Ref (Subp); + + elsif Present (Utyp) and then CW_Or_Has_Controlled_Part (Utyp) then + Set_Returns_By_Ref (Subp); + end if; + end; + + -- Wnen freezing a null procedure, analyze its delayed aspects now + -- because we may not have reached the end of the declarative list when + -- delayed aspects are normally analyzed. This ensures that dispatching + -- calls are properly rewritten when the generated _Postcondition + -- procedure is analyzed in the null procedure body. + + if Nkind (Parent (Subp)) = N_Procedure_Specification + and then Null_Present (Parent (Subp)) + then + Analyze_Entry_Or_Subprogram_Contract (Subp); + end if; + end Freeze_Subprogram; + + ------------------------------ + -- Insert_Post_Call_Actions -- + ------------------------------ + + procedure Insert_Post_Call_Actions (N : Node_Id; Post_Call : List_Id) is + Context : constant Node_Id := Parent (N); + + begin + if Is_Empty_List (Post_Call) then + return; + end if; + + -- Cases where the call is not a member of a statement list. This + -- includes the case where the call is an actual in another function + -- call or indexing, i.e. an expression context as well. + + if not Is_List_Member (N) + or else Nkind_In (Context, N_Function_Call, N_Indexed_Component) + then + -- In Ada 2012 the call may be a function call in an expression + -- (since OUT and IN OUT parameters are now allowed for such calls). + -- The write-back of (in)-out parameters is handled by the back-end, + -- but the constraint checks generated when subtypes of formal and + -- actual don't match must be inserted in the form of assignments. + + if Nkind (Original_Node (N)) = N_Function_Call then + pragma Assert (Ada_Version >= Ada_2012); + -- Functions with '[in] out' parameters are only allowed in Ada + -- 2012. + + -- We used to handle this by climbing up parents to a + -- non-statement/declaration and then simply making a call to + -- Insert_Actions_After (P, Post_Call), but that doesn't work + -- for Ada 2012. If we are in the middle of an expression, e.g. + -- the condition of an IF, this call would insert after the IF + -- statement, which is much too late to be doing the write back. + -- For example: + + -- if Clobber (X) then + -- Put_Line (X'Img); + -- else + -- goto Junk + -- end if; + + -- Now assume Clobber changes X, if we put the write back after + -- the IF, the Put_Line gets the wrong value and the goto causes + -- the write back to be skipped completely. + + -- To deal with this, we replace the call by + + -- do + -- Tnnn : constant function-result-type := function-call; + -- Post_Call actions + -- in + -- Tnnn; + -- end; + + declare + Loc : constant Source_Ptr := Sloc (N); + Tnnn : constant Entity_Id := Make_Temporary (Loc, 'T'); + FRTyp : constant Entity_Id := Etype (N); + Name : constant Node_Id := Relocate_Node (N); + + begin + Prepend_To (Post_Call, + Make_Object_Declaration (Loc, + Defining_Identifier => Tnnn, + Object_Definition => New_Occurrence_Of (FRTyp, Loc), + Constant_Present => True, + Expression => Name)); + + Rewrite (N, + Make_Expression_With_Actions (Loc, + Actions => Post_Call, + Expression => New_Occurrence_Of (Tnnn, Loc))); + + -- We don't want to just blindly call Analyze_And_Resolve + -- because that would cause unwanted recursion on the call. + -- So for a moment set the call as analyzed to prevent that + -- recursion, and get the rest analyzed properly, then reset + -- the analyzed flag, so our caller can continue. + + Set_Analyzed (Name, True); + Analyze_And_Resolve (N, FRTyp); + Set_Analyzed (Name, False); + end; + + -- If not the special Ada 2012 case of a function call, then we must + -- have the triggering statement of a triggering alternative or an + -- entry call alternative, and we can add the post call stuff to the + -- corresponding statement list. + + else + pragma Assert (Nkind_In (Context, N_Entry_Call_Alternative, + N_Triggering_Alternative)); + + if Is_Non_Empty_List (Statements (Context)) then + Insert_List_Before_And_Analyze + (First (Statements (Context)), Post_Call); + else + Set_Statements (Context, Post_Call); + end if; + end if; + + -- A procedure call is always part of a declarative or statement list, + -- however a function call may appear nested within a construct. Most + -- cases of function call nesting are handled in the special case above. + -- The only exception is when the function call acts as an actual in a + -- procedure call. In this case the function call is in a list, but the + -- post-call actions must be inserted after the procedure call. + + elsif Nkind (Context) = N_Procedure_Call_Statement then + Insert_Actions_After (Context, Post_Call); + + -- Otherwise, normal case where N is in a statement sequence, just put + -- the post-call stuff after the call statement. + + else + Insert_Actions_After (N, Post_Call); + end if; + end Insert_Post_Call_Actions; + + ----------------------- + -- Is_Null_Procedure -- + ----------------------- + + function Is_Null_Procedure (Subp : Entity_Id) return Boolean is + Decl : constant Node_Id := Unit_Declaration_Node (Subp); + + begin + if Ekind (Subp) /= E_Procedure then + return False; + + -- Check if this is a declared null procedure + + elsif Nkind (Decl) = N_Subprogram_Declaration then + if not Null_Present (Specification (Decl)) then + return False; + + elsif No (Body_To_Inline (Decl)) then + return False; + + -- Check if the body contains only a null statement, followed by + -- the return statement added during expansion. + + else + declare + Orig_Bod : constant Node_Id := Body_To_Inline (Decl); + + Stat : Node_Id; + Stat2 : Node_Id; + + begin + if Nkind (Orig_Bod) /= N_Subprogram_Body then + return False; + else + -- We must skip SCIL nodes because they are currently + -- implemented as special N_Null_Statement nodes. + + Stat := + First_Non_SCIL_Node + (Statements (Handled_Statement_Sequence (Orig_Bod))); + Stat2 := Next_Non_SCIL_Node (Stat); + + return + Is_Empty_List (Declarations (Orig_Bod)) + and then Nkind (Stat) = N_Null_Statement + and then + (No (Stat2) + or else + (Nkind (Stat2) = N_Simple_Return_Statement + and then No (Next (Stat2)))); + end if; + end; + end if; + + else + return False; + end if; + end Is_Null_Procedure; + + ------------------------------------------- + -- Make_Build_In_Place_Call_In_Allocator -- + ------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Allocator + (Allocator : Node_Id; + Function_Call : Node_Id) + is + Acc_Type : constant Entity_Id := Etype (Allocator); + Loc : constant Source_Ptr := Sloc (Function_Call); + Func_Call : Node_Id := Function_Call; + Ref_Func_Call : Node_Id; + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + New_Allocator : Node_Id; + Return_Obj_Access : Entity_Id; -- temp for function result + Temp_Init : Node_Id; -- initial value of Return_Obj_Access + Alloc_Form : BIP_Allocation_Form; + Pool : Node_Id; -- nonnull if Alloc_Form = User_Storage_Pool + Return_Obj_Actual : Node_Id; -- the temp.all, in caller-allocates case + Chain : Entity_Id; -- activation chain, in case of tasks + + begin + -- Step past qualification or unchecked conversion (the latter can occur + -- in cases of calls to 'Input). + + if Nkind_In (Func_Call, + N_Qualified_Expression, + N_Type_Conversion, + N_Unchecked_Type_Conversion) + then + Func_Call := Expression (Func_Call); + end if; + + -- Mark the call as processed as a build-in-place call + + pragma Assert (not Is_Expanded_Build_In_Place_Call (Func_Call)); + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Available_View (Etype (Function_Id)); + + -- Create a temp for the function result. In the caller-allocates case, + -- this will be initialized to the result of a new uninitialized + -- allocator. Note: we do not use Allocator as the Related_Node of + -- Return_Obj_Access in call to Make_Temporary below as this would + -- create a sort of infinite "recursion". + + Return_Obj_Access := Make_Temporary (Loc, 'R'); + Set_Etype (Return_Obj_Access, Acc_Type); + Set_Can_Never_Be_Null (Acc_Type, False); + -- It gets initialized to null, so we can't have that + + -- When the result subtype is constrained, the return object is + -- allocated on the caller side, and access to it is passed to the + -- function. + + -- Here and in related routines, we must examine the full view of the + -- type, because the view at the point of call may differ from that + -- that in the function body, and the expansion mechanism depends on + -- the characteristics of the full view. + + if Is_Constrained (Underlying_Type (Result_Subt)) then + -- Replace the initialized allocator of form "new T'(Func (...))" + -- with an uninitialized allocator of form "new T", where T is the + -- result subtype of the called function. The call to the function + -- is handled separately further below. + + New_Allocator := + Make_Allocator (Loc, + Expression => New_Occurrence_Of (Result_Subt, Loc)); + Set_No_Initialization (New_Allocator); + + -- Copy attributes to new allocator. Note that the new allocator + -- logically comes from source if the original one did, so copy the + -- relevant flag. This ensures proper treatment of the restriction + -- No_Implicit_Heap_Allocations in this case. + + Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator)); + Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator)); + Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator)); + + Rewrite (Allocator, New_Allocator); + + -- Initial value of the temp is the result of the uninitialized + -- allocator. Unchecked_Convert is needed for T'Input where T is + -- derived from a controlled type. + + Temp_Init := Relocate_Node (Allocator); + + if Nkind_In + (Function_Call, N_Type_Conversion, N_Unchecked_Type_Conversion) + then + Temp_Init := Unchecked_Convert_To (Acc_Type, Temp_Init); + end if; + + -- Indicate that caller allocates, and pass in the return object + + Alloc_Form := Caller_Allocation; + Pool := Make_Null (No_Location); + Return_Obj_Actual := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), + Expression => + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Return_Obj_Access, Loc))); + + -- When the result subtype is unconstrained, the function itself must + -- perform the allocation of the return object, so we pass parameters + -- indicating that. + + else + Temp_Init := Empty; + + -- Case of a user-defined storage pool. Pass an allocation parameter + -- indicating that the function should allocate its result in the + -- pool, and pass the pool. Use 'Unrestricted_Access because the + -- pool may not be aliased. + + if Present (Associated_Storage_Pool (Acc_Type)) then + Alloc_Form := User_Storage_Pool; + Pool := + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of + (Associated_Storage_Pool (Acc_Type), Loc), + Attribute_Name => Name_Unrestricted_Access); + + -- No user-defined pool; pass an allocation parameter indicating that + -- the function should allocate its result on the heap. + + else + Alloc_Form := Global_Heap; + Pool := Make_Null (No_Location); + end if; + + -- The caller does not provide the return object in this case, so we + -- have to pass null for the object access actual. + + Return_Obj_Actual := Empty; + end if; + + -- Declare the temp object + + Insert_Action (Allocator, + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Obj_Access, + Object_Definition => New_Occurrence_Of (Acc_Type, Loc), + Expression => Temp_Init)); + + Ref_Func_Call := Make_Reference (Loc, Func_Call); + + -- Ada 2005 (AI-251): If the type of the allocator is an interface + -- then generate an implicit conversion to force displacement of the + -- "this" pointer. + + if Is_Interface (Designated_Type (Acc_Type)) then + Rewrite + (Ref_Func_Call, + OK_Convert_To (Acc_Type, Ref_Func_Call)); + + -- If the types are incompatible, we need an unchecked conversion. Note + -- that the full types will be compatible, but the types not visibly + -- compatible. + + elsif Nkind_In + (Function_Call, N_Type_Conversion, N_Unchecked_Type_Conversion) + then + Ref_Func_Call := Unchecked_Convert_To (Acc_Type, Ref_Func_Call); + end if; + + declare + Assign : constant Node_Id := + Make_Assignment_Statement (Loc, + Name => New_Occurrence_Of (Return_Obj_Access, Loc), + Expression => Ref_Func_Call); + -- Assign the result of the function call into the temp. In the + -- caller-allocates case, this is overwriting the temp with its + -- initial value, which has no effect. In the callee-allocates case, + -- this is setting the temp to point to the object allocated by the + -- callee. Unchecked_Convert is needed for T'Input where T is derived + -- from a controlled type. + + Actions : List_Id; + -- Actions to be inserted. If there are no tasks, this is just the + -- assignment statement. If the allocated object has tasks, we need + -- to wrap the assignment in a block that activates them. The + -- activation chain of that block must be passed to the function, + -- rather than some outer chain. + begin + if Has_Task (Result_Subt) then + Actions := New_List; + Build_Task_Allocate_Block_With_Init_Stmts + (Actions, Allocator, Init_Stmts => New_List (Assign)); + Chain := Activation_Chain_Entity (Last (Actions)); + else + Actions := New_List (Assign); + Chain := Empty; + end if; + + Insert_Actions (Allocator, Actions); + end; + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly + -- to functions with unconstrained result subtypes. + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form, Pool_Actual => Pool); + + Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Acc_Type); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Master_Actual => Master_Id (Acc_Type), + Chain => Chain); + + -- Add an implicit actual to the function call that provides access + -- to the allocated object. An unchecked conversion to the (specific) + -- result subtype of the function is inserted to handle cases where + -- the access type of the allocator has a class-wide designated type. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Return_Obj_Actual); + + -- Finally, replace the allocator node with a reference to the temp + + Rewrite (Allocator, New_Occurrence_Of (Return_Obj_Access, Loc)); + + Analyze_And_Resolve (Allocator, Acc_Type); + end Make_Build_In_Place_Call_In_Allocator; + + --------------------------------------------------- + -- Make_Build_In_Place_Call_In_Anonymous_Context -- + --------------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Anonymous_Context + (Function_Call : Node_Id) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Func_Call : constant Node_Id := Unqual_Conv (Function_Call); + Function_Id : Entity_Id; + Result_Subt : Entity_Id; + Return_Obj_Id : Entity_Id; + Return_Obj_Decl : Entity_Id; + + begin + -- If the call has already been processed to add build-in-place actuals + -- then return. One place this can occur is for calls to build-in-place + -- functions that occur within a call to a protected operation, where + -- due to rewriting and expansion of the protected call there can be + -- more than one call to Expand_Actuals for the same set of actuals. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Function_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Function_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Function_Id); + + -- If the build-in-place function returns a controlled object, then the + -- object needs to be finalized immediately after the context. Since + -- this case produces a transient scope, the servicing finalizer needs + -- to name the returned object. Create a temporary which is initialized + -- with the function call: + -- + -- Temp_Id : Func_Type := BIP_Func_Call; + -- + -- The initialization expression of the temporary will be rewritten by + -- the expander using the appropriate mechanism in Make_Build_In_Place_ + -- Call_In_Object_Declaration. + + if Needs_Finalization (Result_Subt) then + declare + Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'R'); + Temp_Decl : Node_Id; + + begin + -- Reset the guard on the function call since the following does + -- not perform actual call expansion. + + Set_Is_Expanded_Build_In_Place_Call (Func_Call, False); + + Temp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp_Id, + Object_Definition => + New_Occurrence_Of (Result_Subt, Loc), + Expression => + New_Copy_Tree (Function_Call)); + + Insert_Action (Function_Call, Temp_Decl); + + Rewrite (Function_Call, New_Occurrence_Of (Temp_Id, Loc)); + Analyze (Function_Call); + end; + + -- When the result subtype is definite, an object of the subtype is + -- declared and an access value designating it is passed as an actual. + + elsif Caller_Known_Size (Func_Call, Result_Subt) then + + -- Create a temporary object to hold the function result + + Return_Obj_Id := Make_Temporary (Loc, 'R'); + Set_Etype (Return_Obj_Id, Result_Subt); + + Return_Obj_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Obj_Id, + Aliased_Present => True, + Object_Definition => New_Occurrence_Of (Result_Subt, Loc)); + + Set_No_Initialization (Return_Obj_Decl); + + Insert_Action (Func_Call, Return_Obj_Decl); + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly + -- to functions with unconstrained result subtypes. + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Add an implicit actual to the function call that provides access + -- to the caller's return object. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, New_Occurrence_Of (Return_Obj_Id, Loc)); + + -- When the result subtype is unconstrained, the function must allocate + -- the return object in the secondary stack, so appropriate implicit + -- parameters are added to the call to indicate that. A transient + -- scope is established to ensure eventual cleanup of the result. + + else + -- Pass an allocation parameter indicating that the function should + -- allocate its result on the secondary stack. + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); + + Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Pass a null value to the function since no return object is + -- available on the caller side. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, Function_Id, Empty); + end if; + end Make_Build_In_Place_Call_In_Anonymous_Context; + + -------------------------------------------- + -- Make_Build_In_Place_Call_In_Assignment -- + -------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Assignment + (Assign : Node_Id; + Function_Call : Node_Id) + is + Func_Call : constant Node_Id := Unqual_Conv (Function_Call); + Lhs : constant Node_Id := Name (Assign); + Loc : constant Source_Ptr := Sloc (Function_Call); + Func_Id : Entity_Id; + Obj_Decl : Node_Id; + Obj_Id : Entity_Id; + Ptr_Typ : Entity_Id; + Ptr_Typ_Decl : Node_Id; + New_Expr : Node_Id; + Result_Subt : Entity_Id; + + begin + -- Mark the call as processed as a build-in-place call + + pragma Assert (not Is_Expanded_Build_In_Place_Call (Func_Call)); + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + if Is_Entity_Name (Name (Func_Call)) then + Func_Id := Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + Func_Id := Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + + Result_Subt := Etype (Func_Id); + + -- When the result subtype is unconstrained, an additional actual must + -- be passed to indicate that the caller is providing the return object. + -- This parameter must also be passed when the called function has a + -- controlling result, because dispatching calls to the function needs + -- to be treated effectively the same as calls to class-wide functions. + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Func_Id, Alloc_Form => Caller_Allocation); + + Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call, Func_Id); + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Func_Id, Make_Identifier (Loc, Name_uMaster)); + + -- Add an implicit actual to the function call that provides access to + -- the caller's return object. + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, + Func_Id, + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), + Expression => Relocate_Node (Lhs))); + + -- Create an access type designating the function's result subtype + + Ptr_Typ := Make_Temporary (Loc, 'A'); + + Ptr_Typ_Decl := + 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 (Result_Subt, Loc))); + Insert_After_And_Analyze (Assign, Ptr_Typ_Decl); + + -- Finally, create an access object initialized to a reference to the + -- function call. We know this access value is non-null, so mark the + -- entity accordingly to suppress junk access checks. + + New_Expr := Make_Reference (Loc, Relocate_Node (Func_Call)); + + -- Add a conversion if it's the wrong type + + if Etype (New_Expr) /= Ptr_Typ then + New_Expr := + Make_Unchecked_Type_Conversion (Loc, + New_Occurrence_Of (Ptr_Typ, Loc), New_Expr); + end if; + + Obj_Id := Make_Temporary (Loc, 'R', New_Expr); + Set_Etype (Obj_Id, Ptr_Typ); + Set_Is_Known_Non_Null (Obj_Id); + + Obj_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Obj_Id, + Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc), + Expression => New_Expr); + Insert_After_And_Analyze (Ptr_Typ_Decl, Obj_Decl); + + Rewrite (Assign, Make_Null_Statement (Loc)); + end Make_Build_In_Place_Call_In_Assignment; + + ---------------------------------------------------- + -- Make_Build_In_Place_Call_In_Object_Declaration -- + ---------------------------------------------------- + + procedure Make_Build_In_Place_Call_In_Object_Declaration + (Obj_Decl : Node_Id; + Function_Call : Node_Id) + is + function Get_Function_Id (Func_Call : Node_Id) return Entity_Id; + -- Get the value of Function_Id, below + + --------------------- + -- Get_Function_Id -- + --------------------- + + function Get_Function_Id (Func_Call : Node_Id) return Entity_Id is + begin + if Is_Entity_Name (Name (Func_Call)) then + return Entity (Name (Func_Call)); + + elsif Nkind (Name (Func_Call)) = N_Explicit_Dereference then + return Etype (Name (Func_Call)); + + else + raise Program_Error; + end if; + end Get_Function_Id; + + -- Local variables + + Func_Call : constant Node_Id := Unqual_Conv (Function_Call); + Function_Id : constant Entity_Id := Get_Function_Id (Func_Call); + Loc : constant Source_Ptr := Sloc (Function_Call); + Obj_Loc : constant Source_Ptr := Sloc (Obj_Decl); + Obj_Def_Id : constant Entity_Id := Defining_Identifier (Obj_Decl); + Obj_Typ : constant Entity_Id := Etype (Obj_Def_Id); + Encl_Func : constant Entity_Id := Enclosing_Subprogram (Obj_Def_Id); + Result_Subt : constant Entity_Id := Etype (Function_Id); + + Call_Deref : Node_Id; + Caller_Object : Node_Id; + Def_Id : Entity_Id; + Designated_Type : Entity_Id; + Fmaster_Actual : Node_Id := Empty; + Pool_Actual : Node_Id; + Ptr_Typ : Entity_Id; + Ptr_Typ_Decl : Node_Id; + Pass_Caller_Acc : Boolean := False; + Res_Decl : Node_Id; + + Definite : constant Boolean := + Caller_Known_Size (Func_Call, Result_Subt) + and then not Is_Class_Wide_Type (Obj_Typ); + -- In the case of "X : T'Class := F(...);", where F returns a + -- Caller_Known_Size (specific) tagged type, we treat it as + -- indefinite, because the code for the Definite case below sets the + -- initialization expression of the object to Empty, which would be + -- illegal Ada, and would cause gigi to misallocate X. + + -- Start of processing for Make_Build_In_Place_Call_In_Object_Declaration + + begin + -- If the call has already been processed to add build-in-place actuals + -- then return. + + if Is_Expanded_Build_In_Place_Call (Func_Call) then + return; + end if; + + -- Mark the call as processed as a build-in-place call + + Set_Is_Expanded_Build_In_Place_Call (Func_Call); + + -- Create an access type designating the function's result subtype. + -- We use the type of the original call because it may be a call to an + -- inherited operation, which the expansion has replaced with the parent + -- operation that yields the parent type. Note that this access type + -- must be declared before we establish a transient scope, so that it + -- receives the proper accessibility level. + + if Is_Class_Wide_Type (Obj_Typ) + and then not Is_Interface (Obj_Typ) + and then not Is_Class_Wide_Type (Etype (Function_Call)) + then + Designated_Type := Obj_Typ; + else + Designated_Type := Etype (Function_Call); + end if; + + Ptr_Typ := Make_Temporary (Loc, 'A'); + Ptr_Typ_Decl := + 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 (Designated_Type, Loc))); + + -- The access type and its accompanying object must be inserted after + -- the object declaration in the constrained case, so that the function + -- call can be passed access to the object. In the indefinite case, or + -- if the object declaration is for a return object, the access type and + -- object must be inserted before the object, since the object + -- declaration is rewritten to be a renaming of a dereference of the + -- access object. Note: we need to freeze Ptr_Typ explicitly, because + -- the result object is in a different (transient) scope, so won't cause + -- freezing. + + if Definite and then not Is_Return_Object (Obj_Def_Id) then + Insert_After_And_Analyze (Obj_Decl, Ptr_Typ_Decl); + else + Insert_Action (Obj_Decl, Ptr_Typ_Decl); + end if; + + -- Force immediate freezing of Ptr_Typ because Res_Decl will be + -- elaborated in an inner (transient) scope and thus won't cause + -- freezing by itself. It's not an itype, but it needs to be frozen + -- inside the current subprogram (see Freeze_Outside in freeze.adb). + + Freeze_Itype (Ptr_Typ, Ptr_Typ_Decl); + + -- If the object is a return object of an enclosing build-in-place + -- function, then the implicit build-in-place parameters of the + -- enclosing function are simply passed along to the called function. + -- (Unfortunately, this won't cover the case of extension aggregates + -- where the ancestor part is a build-in-place indefinite function + -- call that should be passed along the caller's parameters. + -- Currently those get mishandled by reassigning the result of the + -- call to the aggregate return object, when the call result should + -- really be directly built in place in the aggregate and not in a + -- temporary. ???) + + if Is_Return_Object (Obj_Def_Id) then + Pass_Caller_Acc := True; + + -- When the enclosing function has a BIP_Alloc_Form formal then we + -- pass it along to the callee (such as when the enclosing function + -- has an unconstrained or tagged result type). + + if Needs_BIP_Alloc_Form (Encl_Func) then + if RTE_Available (RE_Root_Storage_Pool_Ptr) then + Pool_Actual := + New_Occurrence_Of + (Build_In_Place_Formal + (Encl_Func, BIP_Storage_Pool), Loc); + + -- The build-in-place pool formal is not built on e.g. ZFP + + else + Pool_Actual := Empty; + end if; + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Function_Call => Func_Call, + Function_Id => Function_Id, + Alloc_Form_Exp => + New_Occurrence_Of + (Build_In_Place_Formal (Encl_Func, BIP_Alloc_Form), Loc), + Pool_Actual => Pool_Actual); + + -- Otherwise, if enclosing function has a definite result subtype, + -- then caller allocation will be used. + + else + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + end if; + + if Needs_BIP_Finalization_Master (Encl_Func) then + Fmaster_Actual := + New_Occurrence_Of + (Build_In_Place_Formal + (Encl_Func, BIP_Finalization_Master), Loc); + end if; + + -- Retrieve the BIPacc formal from the enclosing function and convert + -- it to the access type of the callee's BIP_Object_Access formal. + + Caller_Object := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => + New_Occurrence_Of + (Etype (Build_In_Place_Formal + (Function_Id, BIP_Object_Access)), + Loc), + Expression => + New_Occurrence_Of + (Build_In_Place_Formal (Encl_Func, BIP_Object_Access), + Loc)); + + -- In the definite case, add an implicit actual to the function call + -- that provides access to the declared object. An unchecked conversion + -- to the (specific) result type of the function is inserted to handle + -- the case where the object is declared with a class-wide type. + + elsif Definite then + Caller_Object := + Make_Unchecked_Type_Conversion (Loc, + Subtype_Mark => New_Occurrence_Of (Result_Subt, Loc), + Expression => New_Occurrence_Of (Obj_Def_Id, Loc)); + + -- When the function has a controlling result, an allocation-form + -- parameter must be passed indicating that the caller is allocating + -- the result object. This is needed because such a function can be + -- called as a dispatching operation and must be treated similarly to + -- functions with indefinite result subtypes. + + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Caller_Allocation); + + -- The allocation for indefinite library-level objects occurs on the + -- heap as opposed to the secondary stack. This accommodates DLLs where + -- the secondary stack is destroyed after each library unload. This is a + -- hybrid mechanism where a stack-allocated object lives on the heap. + + elsif Is_Library_Level_Entity (Obj_Def_Id) + and then not Restriction_Active (No_Implicit_Heap_Allocations) + then + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Global_Heap); + Caller_Object := Empty; + + -- Create a finalization master for the access result type to ensure + -- that the heap allocation can properly chain the object and later + -- finalize it when the library unit goes out of scope. + + if Needs_Finalization (Etype (Func_Call)) then + Build_Finalization_Master + (Typ => Ptr_Typ, + For_Lib_Level => True, + Insertion_Node => Ptr_Typ_Decl); + + Fmaster_Actual := + Make_Attribute_Reference (Loc, + Prefix => + New_Occurrence_Of (Finalization_Master (Ptr_Typ), Loc), + Attribute_Name => Name_Unrestricted_Access); + end if; + + -- In other indefinite cases, pass an indication to do the allocation on + -- the secondary stack and set Caller_Object to Empty so that a null + -- value will be passed for the caller's object address. A transient + -- scope is established to ensure eventual cleanup of the result. + + else + Add_Unconstrained_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Alloc_Form => Secondary_Stack); + Caller_Object := Empty; + + Establish_Transient_Scope (Obj_Decl, Sec_Stack => True); + end if; + + -- Pass along any finalization master actual, which is needed in the + -- case where the called function initializes a return object of an + -- enclosing build-in-place function. + + Add_Finalization_Master_Actual_To_Build_In_Place_Call + (Func_Call => Func_Call, + Func_Id => Function_Id, + Master_Exp => Fmaster_Actual); + + if Nkind (Parent (Obj_Decl)) = N_Extended_Return_Statement + and then Has_Task (Result_Subt) + then + -- Here we're passing along the master that was passed in to this + -- function. + + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, + Master_Actual => + New_Occurrence_Of + (Build_In_Place_Formal (Encl_Func, BIP_Task_Master), Loc)); + + else + Add_Task_Actuals_To_Build_In_Place_Call + (Func_Call, Function_Id, Make_Identifier (Loc, Name_uMaster)); + end if; + + Add_Access_Actual_To_Build_In_Place_Call + (Func_Call, + Function_Id, + Caller_Object, + Is_Access => Pass_Caller_Acc); + + -- Finally, create an access object initialized to a reference to the + -- function call. We know this access value cannot be null, so mark the + -- entity accordingly to suppress the access check. + + Def_Id := Make_Temporary (Loc, 'R', Func_Call); + Set_Etype (Def_Id, Ptr_Typ); + Set_Is_Known_Non_Null (Def_Id); + + if Nkind_In (Function_Call, N_Type_Conversion, + N_Unchecked_Type_Conversion) + then + Res_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc), + Expression => + Make_Unchecked_Type_Conversion (Loc, + New_Occurrence_Of (Ptr_Typ, Loc), + Make_Reference (Loc, Relocate_Node (Func_Call)))); + else + Res_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Def_Id, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Ptr_Typ, Loc), + Expression => + Make_Reference (Loc, Relocate_Node (Func_Call))); + end if; + + Insert_After_And_Analyze (Ptr_Typ_Decl, Res_Decl); + + -- If the result subtype of the called function is definite and is not + -- itself the return expression of an enclosing BIP function, then mark + -- the object as having no initialization. + + if Definite and then not Is_Return_Object (Obj_Def_Id) then + + -- The related object declaration is encased in a transient block + -- because the build-in-place function call contains at least one + -- nested function call that produces a controlled transient + -- temporary: + + -- Obj : ... := BIP_Func_Call (Ctrl_Func_Call); + + -- Since the build-in-place expansion decouples the call from the + -- object declaration, the finalization machinery lacks the context + -- which prompted the generation of the transient block. To resolve + -- this scenario, store the build-in-place call. + + if Scope_Is_Transient and then Node_To_Be_Wrapped = Obj_Decl then + Set_BIP_Initialization_Call (Obj_Def_Id, Res_Decl); + end if; + + Set_Expression (Obj_Decl, Empty); + Set_No_Initialization (Obj_Decl); + + -- In case of an indefinite result subtype, or if the call is the + -- return expression of an enclosing BIP function, rewrite the object + -- declaration as an object renaming where the renamed object is a + -- dereference of <function_Call>'reference: + -- + -- Obj : Subt renames <function_call>'Ref.all; + + else + Call_Deref := + Make_Explicit_Dereference (Obj_Loc, + Prefix => New_Occurrence_Of (Def_Id, Obj_Loc)); + + Rewrite (Obj_Decl, + Make_Object_Renaming_Declaration (Obj_Loc, + Defining_Identifier => Make_Temporary (Obj_Loc, 'D'), + Subtype_Mark => + New_Occurrence_Of (Designated_Type, Obj_Loc), + Name => Call_Deref)); + + -- At this point, Defining_Identifier (Obj_Decl) is no longer equal + -- to Obj_Def_Id. + + Set_Renamed_Object (Defining_Identifier (Obj_Decl), Call_Deref); + + -- If the original entity comes from source, then mark the new + -- entity as needing debug information, even though it's defined + -- by a generated renaming that does not come from source, so that + -- the Materialize_Entity flag will be set on the entity when + -- Debug_Renaming_Declaration is called during analysis. + + if Comes_From_Source (Obj_Def_Id) then + Set_Debug_Info_Needed (Defining_Identifier (Obj_Decl)); + end if; + + Analyze (Obj_Decl); + Replace_Renaming_Declaration_Id + (Obj_Decl, Original_Node (Obj_Decl)); + end if; + end Make_Build_In_Place_Call_In_Object_Declaration; + + ------------------------------------------------- + -- Make_Build_In_Place_Iface_Call_In_Allocator -- + ------------------------------------------------- + + procedure Make_Build_In_Place_Iface_Call_In_Allocator + (Allocator : Node_Id; + Function_Call : Node_Id) + is + BIP_Func_Call : constant Node_Id := + Unqual_BIP_Iface_Function_Call (Function_Call); + Loc : constant Source_Ptr := Sloc (Function_Call); + + Anon_Type : Entity_Id; + Tmp_Decl : Node_Id; + Tmp_Id : Entity_Id; + + begin + -- No action of the call has already been processed + + if Is_Expanded_Build_In_Place_Call (BIP_Func_Call) then + return; + end if; + + Tmp_Id := Make_Temporary (Loc, 'D'); + + -- Insert a temporary before N initialized with the BIP function call + -- without its enclosing type conversions and analyze it without its + -- expansion. This temporary facilitates us reusing the BIP machinery, + -- which takes care of adding the extra build-in-place actuals and + -- transforms this object declaration into an object renaming + -- declaration. + + Anon_Type := Create_Itype (E_Anonymous_Access_Type, Function_Call); + Set_Directly_Designated_Type (Anon_Type, Etype (BIP_Func_Call)); + Set_Etype (Anon_Type, Anon_Type); + + Tmp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Tmp_Id, + Object_Definition => New_Occurrence_Of (Anon_Type, Loc), + Expression => + Make_Allocator (Loc, + Expression => + Make_Qualified_Expression (Loc, + Subtype_Mark => + New_Occurrence_Of (Etype (BIP_Func_Call), Loc), + Expression => New_Copy_Tree (BIP_Func_Call)))); + + Expander_Mode_Save_And_Set (False); + Insert_Action (Allocator, Tmp_Decl); + Expander_Mode_Restore; + + Make_Build_In_Place_Call_In_Allocator + (Allocator => Expression (Tmp_Decl), + Function_Call => Expression (Expression (Tmp_Decl))); + + Rewrite (Allocator, New_Occurrence_Of (Tmp_Id, Loc)); + end Make_Build_In_Place_Iface_Call_In_Allocator; + + --------------------------------------------------------- + -- Make_Build_In_Place_Iface_Call_In_Anonymous_Context -- + --------------------------------------------------------- + + procedure Make_Build_In_Place_Iface_Call_In_Anonymous_Context + (Function_Call : Node_Id) + is + BIP_Func_Call : constant Node_Id := + Unqual_BIP_Iface_Function_Call (Function_Call); + Loc : constant Source_Ptr := Sloc (Function_Call); + + Tmp_Decl : Node_Id; + Tmp_Id : Entity_Id; + + begin + -- No action of the call has already been processed + + if Is_Expanded_Build_In_Place_Call (BIP_Func_Call) then + return; + end if; + + pragma Assert (Needs_Finalization (Etype (BIP_Func_Call))); + + -- Insert a temporary before the call initialized with function call to + -- reuse the BIP machinery which takes care of adding the extra build-in + -- place actuals and transforms this object declaration into an object + -- renaming declaration. + + Tmp_Id := Make_Temporary (Loc, 'D'); + + Tmp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Tmp_Id, + Object_Definition => + New_Occurrence_Of (Etype (Function_Call), Loc), + Expression => Relocate_Node (Function_Call)); + + Expander_Mode_Save_And_Set (False); + Insert_Action (Function_Call, Tmp_Decl); + Expander_Mode_Restore; + + Make_Build_In_Place_Iface_Call_In_Object_Declaration + (Obj_Decl => Tmp_Decl, + Function_Call => Expression (Tmp_Decl)); + end Make_Build_In_Place_Iface_Call_In_Anonymous_Context; + + ---------------------------------------------------------- + -- Make_Build_In_Place_Iface_Call_In_Object_Declaration -- + ---------------------------------------------------------- + + procedure Make_Build_In_Place_Iface_Call_In_Object_Declaration + (Obj_Decl : Node_Id; + Function_Call : Node_Id) + is + BIP_Func_Call : constant Node_Id := + Unqual_BIP_Iface_Function_Call (Function_Call); + Loc : constant Source_Ptr := Sloc (Function_Call); + Obj_Id : constant Entity_Id := Defining_Entity (Obj_Decl); + + Tmp_Decl : Node_Id; + Tmp_Id : Entity_Id; + + begin + -- No action of the call has already been processed + + if Is_Expanded_Build_In_Place_Call (BIP_Func_Call) then + return; + end if; + + Tmp_Id := Make_Temporary (Loc, 'D'); + + -- Insert a temporary before N initialized with the BIP function call + -- without its enclosing type conversions and analyze it without its + -- expansion. This temporary facilitates us reusing the BIP machinery, + -- which takes care of adding the extra build-in-place actuals and + -- transforms this object declaration into an object renaming + -- declaration. + + Tmp_Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Tmp_Id, + Object_Definition => + New_Occurrence_Of (Etype (BIP_Func_Call), Loc), + Expression => New_Copy_Tree (BIP_Func_Call)); + + Expander_Mode_Save_And_Set (False); + Insert_Action (Obj_Decl, Tmp_Decl); + Expander_Mode_Restore; + + Make_Build_In_Place_Call_In_Object_Declaration + (Obj_Decl => Tmp_Decl, + Function_Call => Expression (Tmp_Decl)); + + pragma Assert (Nkind (Tmp_Decl) = N_Object_Renaming_Declaration); + + -- Replace the original build-in-place function call by a reference to + -- the resulting temporary object renaming declaration. In this way, + -- all the interface conversions performed in the original Function_Call + -- on the build-in-place object are preserved. + + Rewrite (BIP_Func_Call, New_Occurrence_Of (Tmp_Id, Loc)); + + -- Replace the original object declaration by an internal object + -- renaming declaration. This leaves the generated code more clean (the + -- build-in-place function call in an object renaming declaration and + -- displacements of the pointer to the build-in-place object in another + -- renaming declaration) and allows us to invoke the routine that takes + -- care of replacing the identifier of the renaming declaration (routine + -- originally developed for the regular build-in-place management). + + Rewrite (Obj_Decl, + Make_Object_Renaming_Declaration (Loc, + Defining_Identifier => Make_Temporary (Loc, 'D'), + Subtype_Mark => New_Occurrence_Of (Etype (Obj_Id), Loc), + Name => Function_Call)); + Analyze (Obj_Decl); + + Replace_Renaming_Declaration_Id (Obj_Decl, Original_Node (Obj_Decl)); + end Make_Build_In_Place_Iface_Call_In_Object_Declaration; + + -------------------------------------------- + -- Make_CPP_Constructor_Call_In_Allocator -- + -------------------------------------------- + + procedure Make_CPP_Constructor_Call_In_Allocator + (Allocator : Node_Id; + Function_Call : Node_Id) + is + Loc : constant Source_Ptr := Sloc (Function_Call); + Acc_Type : constant Entity_Id := Etype (Allocator); + Function_Id : constant Entity_Id := Entity (Name (Function_Call)); + Result_Subt : constant Entity_Id := Available_View (Etype (Function_Id)); + + New_Allocator : Node_Id; + Return_Obj_Access : Entity_Id; + Tmp_Obj : Node_Id; + + begin + pragma Assert (Nkind (Allocator) = N_Allocator + and then Nkind (Function_Call) = N_Function_Call); + pragma Assert (Convention (Function_Id) = Convention_CPP + and then Is_Constructor (Function_Id)); + pragma Assert (Is_Constrained (Underlying_Type (Result_Subt))); + + -- Replace the initialized allocator of form "new T'(Func (...))" with + -- an uninitialized allocator of form "new T", where T is the result + -- subtype of the called function. The call to the function is handled + -- separately further below. + + New_Allocator := + Make_Allocator (Loc, + Expression => New_Occurrence_Of (Result_Subt, Loc)); + Set_No_Initialization (New_Allocator); + + -- Copy attributes to new allocator. Note that the new allocator + -- logically comes from source if the original one did, so copy the + -- relevant flag. This ensures proper treatment of the restriction + -- No_Implicit_Heap_Allocations in this case. + + Set_Storage_Pool (New_Allocator, Storage_Pool (Allocator)); + Set_Procedure_To_Call (New_Allocator, Procedure_To_Call (Allocator)); + Set_Comes_From_Source (New_Allocator, Comes_From_Source (Allocator)); + + Rewrite (Allocator, New_Allocator); + + -- Create a new access object and initialize it to the result of the + -- new uninitialized allocator. Note: we do not use Allocator as the + -- Related_Node of Return_Obj_Access in call to Make_Temporary below + -- as this would create a sort of infinite "recursion". + + Return_Obj_Access := Make_Temporary (Loc, 'R'); + Set_Etype (Return_Obj_Access, Acc_Type); + + -- Generate: + -- Rnnn : constant ptr_T := new (T); + -- Init (Rnn.all,...); + + Tmp_Obj := + Make_Object_Declaration (Loc, + Defining_Identifier => Return_Obj_Access, + Constant_Present => True, + Object_Definition => New_Occurrence_Of (Acc_Type, Loc), + Expression => Relocate_Node (Allocator)); + Insert_Action (Allocator, Tmp_Obj); + + Insert_List_After_And_Analyze (Tmp_Obj, + Build_Initialization_Call (Loc, + Id_Ref => + Make_Explicit_Dereference (Loc, + Prefix => New_Occurrence_Of (Return_Obj_Access, Loc)), + Typ => Etype (Function_Id), + Constructor_Ref => Function_Call)); + + -- Finally, replace the allocator node with a reference to the result of + -- the function call itself (which will effectively be an access to the + -- object created by the allocator). + + Rewrite (Allocator, New_Occurrence_Of (Return_Obj_Access, Loc)); + + -- Ada 2005 (AI-251): If the type of the allocator is an interface then + -- generate an implicit conversion to force displacement of the "this" + -- pointer. + + if Is_Interface (Designated_Type (Acc_Type)) then + Rewrite (Allocator, Convert_To (Acc_Type, Relocate_Node (Allocator))); + end if; + + Analyze_And_Resolve (Allocator, Acc_Type); + end Make_CPP_Constructor_Call_In_Allocator; + + ----------------------------------- + -- Needs_BIP_Finalization_Master -- + ----------------------------------- + + function Needs_BIP_Finalization_Master + (Func_Id : Entity_Id) return Boolean + is + pragma Assert (Is_Build_In_Place_Function (Func_Id)); + Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); + begin + -- A formal giving the finalization master is needed for build-in-place + -- functions whose result type needs finalization or is a tagged type. + -- Tagged primitive build-in-place functions need such a formal because + -- they can be called by a dispatching call, and extensions may require + -- finalization even if the root type doesn't. This means they're also + -- needed for tagged nonprimitive build-in-place functions with tagged + -- results, since such functions can be called via access-to-function + -- types, and those can be used to call primitives, so masters have to + -- be passed to all such build-in-place functions, primitive or not. + + return + not Restriction_Active (No_Finalization) + and then (Needs_Finalization (Func_Typ) + or else Is_Tagged_Type (Func_Typ)); + end Needs_BIP_Finalization_Master; + + -------------------------- + -- Needs_BIP_Alloc_Form -- + -------------------------- + + function Needs_BIP_Alloc_Form (Func_Id : Entity_Id) return Boolean is + pragma Assert (Is_Build_In_Place_Function (Func_Id)); + Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); + begin + return not Is_Constrained (Func_Typ) or else Is_Tagged_Type (Func_Typ); + end Needs_BIP_Alloc_Form; + + -------------------------------------- + -- Needs_Result_Accessibility_Level -- + -------------------------------------- + + function Needs_Result_Accessibility_Level + (Func_Id : Entity_Id) return Boolean + is + Func_Typ : constant Entity_Id := Underlying_Type (Etype (Func_Id)); + + function Has_Unconstrained_Access_Discriminant_Component + (Comp_Typ : Entity_Id) return Boolean; + -- Returns True if any component of the type has an unconstrained access + -- discriminant. + + ----------------------------------------------------- + -- Has_Unconstrained_Access_Discriminant_Component -- + ----------------------------------------------------- + + function Has_Unconstrained_Access_Discriminant_Component + (Comp_Typ : Entity_Id) return Boolean + is + begin + if not Is_Limited_Type (Comp_Typ) then + return False; + + -- Only limited types can have access discriminants with + -- defaults. + + elsif Has_Unconstrained_Access_Discriminants (Comp_Typ) then + return True; + + elsif Is_Array_Type (Comp_Typ) then + return Has_Unconstrained_Access_Discriminant_Component + (Underlying_Type (Component_Type (Comp_Typ))); + + elsif Is_Record_Type (Comp_Typ) then + declare + Comp : Entity_Id; + + begin + Comp := First_Component (Comp_Typ); + while Present (Comp) loop + if Has_Unconstrained_Access_Discriminant_Component + (Underlying_Type (Etype (Comp))) + then + return True; + end if; + + Next_Component (Comp); + end loop; + end; + end if; + + return False; + end Has_Unconstrained_Access_Discriminant_Component; + + Feature_Disabled : constant Boolean := True; + -- Temporary + + -- Start of processing for Needs_Result_Accessibility_Level + + begin + -- False if completion unavailable (how does this happen???) + + if not Present (Func_Typ) then + return False; + + elsif Feature_Disabled then + return False; + + -- False if not a function, also handle enum-lit renames case + + elsif Func_Typ = Standard_Void_Type + or else Is_Scalar_Type (Func_Typ) + then + return False; + + -- Handle a corner case, a cross-dialect subp renaming. For example, + -- an Ada 2012 renaming of an Ada 2005 subprogram. This can occur when + -- an Ada 2005 (or earlier) unit references predefined run-time units. + + elsif Present (Alias (Func_Id)) then + + -- Unimplemented: a cross-dialect subp renaming which does not set + -- the Alias attribute (e.g., a rename of a dereference of an access + -- to subprogram value). ??? + + return Present (Extra_Accessibility_Of_Result (Alias (Func_Id))); + + -- Remaining cases require Ada 2012 mode + + elsif Ada_Version < Ada_2012 then + return False; + + elsif Ekind (Func_Typ) = E_Anonymous_Access_Type + or else Is_Tagged_Type (Func_Typ) + then + -- In the case of, say, a null tagged record result type, the need + -- for this extra parameter might not be obvious. This function + -- returns True for all tagged types for compatibility reasons. + -- A function with, say, a tagged null controlling result type might + -- be overridden by a primitive of an extension having an access + -- discriminant and the overrider and overridden must have compatible + -- calling conventions (including implicitly declared parameters). + -- Similarly, values of one access-to-subprogram type might designate + -- both a primitive subprogram of a given type and a function + -- which is, for example, not a primitive subprogram of any type. + -- Again, this requires calling convention compatibility. + -- It might be possible to solve these issues by introducing + -- wrappers, but that is not the approach that was chosen. + + return True; + + elsif Has_Unconstrained_Access_Discriminants (Func_Typ) then + return True; + + elsif Has_Unconstrained_Access_Discriminant_Component (Func_Typ) then + return True; + + -- False for all other cases + + else + return False; + end if; + end Needs_Result_Accessibility_Level; + + ------------------------------------- + -- Replace_Renaming_Declaration_Id -- + ------------------------------------- + + procedure Replace_Renaming_Declaration_Id + (New_Decl : Node_Id; + Orig_Decl : Node_Id) + is + New_Id : constant Entity_Id := Defining_Entity (New_Decl); + Orig_Id : constant Entity_Id := Defining_Entity (Orig_Decl); + + begin + Set_Chars (New_Id, Chars (Orig_Id)); + + -- Swap next entity links in preparation for exchanging entities + + declare + Next_Id : constant Entity_Id := Next_Entity (New_Id); + begin + Set_Next_Entity (New_Id, Next_Entity (Orig_Id)); + Set_Next_Entity (Orig_Id, Next_Id); + end; + + Set_Homonym (New_Id, Homonym (Orig_Id)); + Exchange_Entities (New_Id, Orig_Id); + + -- Preserve source indication of original declaration, so that xref + -- information is properly generated for the right entity. + + Preserve_Comes_From_Source (New_Decl, Orig_Decl); + Preserve_Comes_From_Source (Orig_Id, Orig_Decl); + + Set_Comes_From_Source (New_Id, False); + end Replace_Renaming_Declaration_Id; + + --------------------------------- + -- Rewrite_Function_Call_For_C -- + --------------------------------- + + procedure Rewrite_Function_Call_For_C (N : Node_Id) is + Orig_Func : constant Entity_Id := Entity (Name (N)); + Func_Id : constant Entity_Id := Ultimate_Alias (Orig_Func); + Par : constant Node_Id := Parent (N); + Proc_Id : constant Entity_Id := Corresponding_Procedure (Func_Id); + Loc : constant Source_Ptr := Sloc (Par); + Actuals : List_Id; + Last_Actual : Node_Id; + Last_Formal : Entity_Id; + + -- Start of processing for Rewrite_Function_Call_For_C + + begin + -- The actuals may be given by named associations, so the added actual + -- that is the target of the return value of the call must be a named + -- association as well, so we retrieve the name of the generated + -- out_formal. + + Last_Formal := First_Formal (Proc_Id); + while Present (Next_Formal (Last_Formal)) loop + Last_Formal := Next_Formal (Last_Formal); + end loop; + + Actuals := Parameter_Associations (N); + + -- The original function may lack parameters + + if No (Actuals) then + Actuals := New_List; + end if; + + -- If the function call is the expression of an assignment statement, + -- transform the assignment into a procedure call. Generate: + + -- LHS := Func_Call (...); + + -- Proc_Call (..., LHS); + + -- If function is inherited, a conversion may be necessary. + + if Nkind (Par) = N_Assignment_Statement then + Last_Actual := Name (Par); + + if not Comes_From_Source (Orig_Func) + and then Etype (Orig_Func) /= Etype (Func_Id) + then + Last_Actual := + Make_Type_Conversion (Loc, + New_Occurrence_Of (Etype (Func_Id), Loc), + Last_Actual); + end if; + + Append_To (Actuals, + Make_Parameter_Association (Loc, + Selector_Name => + Make_Identifier (Loc, Chars (Last_Formal)), + Explicit_Actual_Parameter => Last_Actual)); + + Rewrite (Par, + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Id, Loc), + Parameter_Associations => Actuals)); + Analyze (Par); + + -- Otherwise the context is an expression. Generate a temporary and a + -- procedure call to obtain the function result. Generate: + + -- ... Func_Call (...) ... + + -- Temp : ...; + -- Proc_Call (..., Temp); + -- ... Temp ... + + else + declare + Temp_Id : constant Entity_Id := Make_Temporary (Loc, 'T'); + Call : Node_Id; + Decl : Node_Id; + + begin + -- Generate: + -- Temp : ...; + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Temp_Id, + Object_Definition => + New_Occurrence_Of (Etype (Func_Id), Loc)); + + -- Generate: + -- Proc_Call (..., Temp); + + Append_To (Actuals, + Make_Parameter_Association (Loc, + Selector_Name => + Make_Identifier (Loc, Chars (Last_Formal)), + Explicit_Actual_Parameter => + New_Occurrence_Of (Temp_Id, Loc))); + + Call := + Make_Procedure_Call_Statement (Loc, + Name => New_Occurrence_Of (Proc_Id, Loc), + Parameter_Associations => Actuals); + + Insert_Actions (Par, New_List (Decl, Call)); + Rewrite (N, New_Occurrence_Of (Temp_Id, Loc)); + end; + end if; + end Rewrite_Function_Call_For_C; + + ------------------------------------ + -- Set_Enclosing_Sec_Stack_Return -- + ------------------------------------ + + procedure Set_Enclosing_Sec_Stack_Return (N : Node_Id) is + P : Node_Id := N; + + begin + -- Due to a possible mix of internally generated blocks, source blocks + -- and loops, the scope stack may not be contiguous as all labels are + -- inserted at the top level within the related function. Instead, + -- perform a parent-based traversal and mark all appropriate constructs. + + while Present (P) loop + + -- Mark the label of a source or internally generated block or + -- loop. + + if Nkind_In (P, N_Block_Statement, N_Loop_Statement) then + Set_Sec_Stack_Needed_For_Return (Entity (Identifier (P))); + + -- Mark the enclosing function + + elsif Nkind (P) = N_Subprogram_Body then + if Present (Corresponding_Spec (P)) then + Set_Sec_Stack_Needed_For_Return (Corresponding_Spec (P)); + else + Set_Sec_Stack_Needed_For_Return (Defining_Entity (P)); + end if; + + -- Do not go beyond the enclosing function + + exit; + end if; + + P := Parent (P); + end loop; + end Set_Enclosing_Sec_Stack_Return; + + ------------------------------------ + -- Unqual_BIP_Iface_Function_Call -- + ------------------------------------ + + function Unqual_BIP_Iface_Function_Call (Expr : Node_Id) return Node_Id is + Has_Pointer_Displacement : Boolean := False; + On_Object_Declaration : Boolean := False; + -- Remember if processing the renaming expressions on recursion we have + -- traversed an object declaration, since we can traverse many object + -- declaration renamings but just one regular object declaration. + + function Unqual_BIP_Function_Call (Expr : Node_Id) return Node_Id; + -- Search for a build-in-place function call skipping any qualification + -- including qualified expressions, type conversions, references, calls + -- to displace the pointer to the object, and renamings. Return Empty if + -- no build-in-place function call is found. + + ------------------------------ + -- Unqual_BIP_Function_Call -- + ------------------------------ + + function Unqual_BIP_Function_Call (Expr : Node_Id) return Node_Id is + begin + -- Recurse to handle case of multiple levels of qualification and/or + -- conversion. + + if Nkind_In (Expr, N_Qualified_Expression, + N_Type_Conversion, + N_Unchecked_Type_Conversion) + then + return Unqual_BIP_Function_Call (Expression (Expr)); + + -- Recurse to handle case of multiple levels of references and + -- explicit dereferences. + + elsif Nkind_In (Expr, N_Attribute_Reference, + N_Explicit_Dereference, + N_Reference) + then + return Unqual_BIP_Function_Call (Prefix (Expr)); + + -- Recurse on object renamings + + elsif Nkind (Expr) = N_Identifier + and then Present (Entity (Expr)) + and then Ekind_In (Entity (Expr), E_Constant, E_Variable) + and then Nkind (Parent (Entity (Expr))) = + N_Object_Renaming_Declaration + and then Present (Renamed_Object (Entity (Expr))) + then + return Unqual_BIP_Function_Call (Renamed_Object (Entity (Expr))); + + -- Recurse on the initializing expression of the first reference of + -- an object declaration. + + elsif not On_Object_Declaration + and then Nkind (Expr) = N_Identifier + and then Present (Entity (Expr)) + and then Ekind_In (Entity (Expr), E_Constant, E_Variable) + and then Nkind (Parent (Entity (Expr))) = N_Object_Declaration + and then Present (Expression (Parent (Entity (Expr)))) + then + On_Object_Declaration := True; + return + Unqual_BIP_Function_Call (Expression (Parent (Entity (Expr)))); + + -- Recurse to handle calls to displace the pointer to the object to + -- reference a secondary dispatch table. + + elsif Nkind (Expr) = N_Function_Call + and then Nkind (Name (Expr)) in N_Has_Entity + and then Present (Entity (Name (Expr))) + and then RTU_Loaded (Ada_Tags) + and then RTE_Available (RE_Displace) + and then Is_RTE (Entity (Name (Expr)), RE_Displace) + then + Has_Pointer_Displacement := True; + return + Unqual_BIP_Function_Call (First (Parameter_Associations (Expr))); + + -- Normal case: check if the inner expression is a BIP function call + -- and the pointer to the object is displaced. + + elsif Has_Pointer_Displacement + and then Is_Build_In_Place_Function_Call (Expr) + then + return Expr; + + else + return Empty; + end if; + end Unqual_BIP_Function_Call; + + -- Start of processing for Unqual_BIP_Iface_Function_Call + + begin + if Nkind (Expr) = N_Identifier and then No (Entity (Expr)) then + + -- Can happen for X'Elab_Spec in the binder-generated file + + return Empty; + end if; + + return Unqual_BIP_Function_Call (Expr); + end Unqual_BIP_Iface_Function_Call; + +end Exp_Ch6;