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| author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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| date | Mon, 25 May 2020 18:13:55 +0900 |
| parents | 1830386684a0 |
| children |
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------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ C H 6 -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2019, 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 Aspects; use Aspects; 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_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. function Check_Number_Of_Actuals (Subp_Call : Node_Id; Subp_Id : Entity_Id) return Boolean; -- Given a subprogram call to the given subprogram return True if the -- number of actual parameters (including extra actuals) is correct. 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 nonscalar 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 -- Nothing to do when the size of the object is known, and the caller is -- in charge of allocating it, and the callee doesn't unconditionally -- require an allocation form (such as due to having a tagged result). if not Needs_BIP_Alloc_Form (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); 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 Needs_BIP_Task_Actuals (Function_Id) 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_Suffix : constant String := 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; -- We search for a formal with a matching suffix. We can't search -- for the full name, because of the code at the end of Sem_Ch6.- -- Create_Extra_Formals, which copies the Extra_Formals over to -- the Alias of an instance, which will cause the formals to have -- "incorrect" names. loop pragma Assert (Present (Extra_Formal)); declare Name : constant String := Get_Name_String (Chars (Extra_Formal)); begin exit when Name'Length >= Formal_Suffix'Length and then Formal_Suffix = Name (Name'Last - Formal_Suffix'Length + 1 .. Name'Last); end; 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_Number_Of_Actuals -- ----------------------------- function Check_Number_Of_Actuals (Subp_Call : Node_Id; Subp_Id : Entity_Id) return Boolean is Formal : Entity_Id; Actual : Node_Id; begin pragma Assert (Nkind_In (Subp_Call, N_Entry_Call_Statement, N_Function_Call, N_Procedure_Call_Statement)); Formal := First_Formal_With_Extras (Subp_Id); Actual := First_Actual (Subp_Call); while Present (Formal) and then Present (Actual) loop Next_Formal_With_Extras (Formal); Next_Actual (Actual); end loop; return No (Formal) and then No (Actual); end Check_Number_Of_Actuals; -------------------------------- -- 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 (Bit_Packed_Array : Boolean); -- 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. If Bit_Packed_Array is True, -- the procedure is called for a bit-packed array actual. 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 formal is of a by_reference type or -- is aliased, then the program is illegal (this can only happen in -- the presence of representation clauses that force a misalignment) -- If the formal is a by_reference parameter imposed by a DEC pragma, -- emit a warning 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. function Requires_Atomic_Or_Volatile_Copy return Boolean; -- Returns whether a copy is required as per RM C.6(19) and gives a -- warning in this case. --------------------------- -- 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; -- The new code will be properly analyzed below and the setting of -- the Do_Range_Check flag recomputed so remove the obsolete one. Set_Do_Range_Check (Actual, False); if Nkind (Actual) = N_Type_Conversion then Set_Do_Range_Check (Expression (Actual), False); 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 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_In_Out_Parameter or else (Is_Array_Type (F_Typ) and then not Is_Constrained (F_Typ)) or else Has_Discriminants (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; -- Access types are passed in without checks, but if a copy-back is -- required for a null-excluding check on an in-out or out parameter, -- then the initial value is that of the actual. elsif Is_Access_Type (E_Formal) and then Can_Never_Be_Null (Etype (Actual)) and then not Can_Never_Be_Null (E_Formal) then Init := New_Occurrence_Of (Var, Loc); 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); Set_Is_True_Constant (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 if Is_Access_Type (E_Formal) and then Can_Never_Be_Null (Etype (Actual)) and then not Can_Never_Be_Null (E_Formal) then Append_To (Post_Call, Make_Raise_Constraint_Error (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Occurrence_Of (Temp, Loc), Right_Opnd => Make_Null (Loc)), Reason => CE_Access_Check_Failed)); end if; 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 (Bit_Packed_Array : Boolean) 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 -- ??? We need to do the copy for a bit-packed array because this is -- where the rewriting into a mask-and-shift sequence is done. But of -- course this may break the program if it expects bits to be really -- passed by reference. That's what we have done historically though. if not Bit_Packed_Array and then 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); Set_Is_True_Constant (Temp, False); -- 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 -- Generate range check if required if Do_Range_Check (Actual) then Generate_Range_Check (Actual, E_Formal, CE_Range_Check_Failed); end if; -- If there is a type conversion in the actual, it will be reinstated -- below, the new instance will be properly analyzed and the setting -- of the Do_Range_Check flag recomputed so remove the obsolete one. if Nkind (Actual) = N_Type_Conversion then Set_Do_Range_Check (Expression (Actual), False); end if; -- 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)) or else Is_Aliased (Formal) or else (Mechanism (Formal) = By_Reference and then not Has_Foreign_Convention (Subp)) 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 or a warning 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 Ekind (Scope (Formal)) = E_Procedure 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; ---------------------------------------- -- Requires_Atomic_Or_Volatile_Copy -- ---------------------------------------- function Requires_Atomic_Or_Volatile_Copy return Boolean is begin -- If the formal is already passed by copy, no need to do anything if Is_By_Copy_Type (E_Formal) then return False; end if; -- Check for atomicity mismatch if Is_Atomic_Object (Actual) and then not Is_Atomic (E_Formal) then if Comes_From_Source (N) then Error_Msg_N ("?atomic actual passed by copy (RM C.6(19))", Actual); end if; return True; end if; -- Check for volatility mismatch if Is_Volatile_Object (Actual) and then not Is_Volatile (E_Formal) then if Comes_From_Source (N) then Error_Msg_N ("?volatile actual passed by copy (RM C.6(19))", Actual); end if; return True; end if; return False; end Requires_Atomic_Or_Volatile_Copy; -- 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), but on return a null-excluding check may be -- required (see below). 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 (Bit_Packed_Array => True); -- If a nonscalar 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 (Bit_Packed_Array => False); -- 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, but null-excluding checks on return may be -- required. elsif Is_Access_Type (E_Formal) and then not Is_Tagged_Type (Designated_Type (E_Formal)) and then (not Same_Type (E_Formal, E_Actual) or else (Can_Never_Be_Null (E_Actual) and then not Can_Never_Be_Null (E_Formal))) then Add_Call_By_Copy_Code; -- We may need to force a copy because of atomicity or volatility -- considerations. elsif Requires_Atomic_Or_Volatile_Copy 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 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 -- Generate range check if required if Do_Range_Check (Actual) then Generate_Range_Check (Actual, E_Formal, CE_Range_Check_Failed); end if; -- 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 (Bit_Packed_Array => True); -- If a nonscalar 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 (Bit_Packed_Array => False); -- 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; -- We may need to force a copy because of atomicity or volatility -- considerations. elsif Requires_Atomic_Or_Volatile_Copy 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 Can_Fold_Predicate_Call (P : Entity_Id) return Boolean; -- Try to constant-fold a predicate check, which often enough is a -- simple arithmetic expression that can be computed statically if -- its argument is static. This cleans up the output of CCG, even -- though useless predicate checks will be generally removed by -- back-end optimizations. 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_Class_Wide_Interface_Type (E : Entity_Id) return Boolean; -- Return True when E is a class-wide interface type or an access to -- a class-wide interface type. 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; ----------------------------- -- Can_Fold_Predicate_Call -- ----------------------------- function Can_Fold_Predicate_Call (P : Entity_Id) return Boolean is Actual : Node_Id; function May_Fold (N : Node_Id) return Traverse_Result; -- The predicate expression is foldable if it only contains operators -- and literals. During this check, we also replace occurrences of -- the formal of the constructed predicate function with the static -- value of the actual. This is done on a copy of the analyzed -- expression for the predicate. -------------- -- May_Fold -- -------------- function May_Fold (N : Node_Id) return Traverse_Result is begin case Nkind (N) is when N_Binary_Op | N_Unary_Op => return OK; when N_Expanded_Name | N_Identifier => if Ekind (Entity (N)) = E_In_Parameter and then Entity (N) = First_Entity (P) then Rewrite (N, New_Copy (Actual)); Set_Is_Static_Expression (N); return OK; elsif Ekind (Entity (N)) = E_Enumeration_Literal then return OK; else return Abandon; end if; when N_Case_Expression | N_If_Expression => return OK; when N_Integer_Literal => return OK; when others => return Abandon; end case; end May_Fold; function Try_Fold is new Traverse_Func (May_Fold); -- Other lLocal variables Subt : constant Entity_Id := Etype (First_Entity (P)); Aspect : Node_Id; Pred : Node_Id; -- Start of processing for Can_Fold_Predicate_Call begin -- Folding is only interesting if the actual is static and its type -- has a Dynamic_Predicate aspect. For CodePeer we preserve the -- function call. Actual := First (Parameter_Associations (Call_Node)); Aspect := Find_Aspect (Subt, Aspect_Dynamic_Predicate); -- If actual is a declared constant, retrieve its value if Is_Entity_Name (Actual) and then Ekind (Entity (Actual)) = E_Constant then Actual := Constant_Value (Entity (Actual)); end if; if No (Actual) or else Nkind (Actual) /= N_Integer_Literal or else not Has_Dynamic_Predicate_Aspect (Subt) or else No (Aspect) or else CodePeer_Mode then return False; end if; -- Retrieve the analyzed expression for the predicate Pred := New_Copy_Tree (Expression (Aspect)); if Try_Fold (Pred) = OK then Rewrite (Call_Node, Pred); Analyze_And_Resolve (Call_Node, Standard_Boolean); return True; -- Otherwise continue the expansion of the function call else return False; end if; end Can_Fold_Predicate_Call; --------------------------- -- 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_Class_Wide_Interface_Type -- ---------------------------------- function Is_Class_Wide_Interface_Type (E : Entity_Id) return Boolean is DDT : Entity_Id; Typ : Entity_Id := E; begin if Has_Non_Limited_View (Typ) then Typ := Non_Limited_View (Typ); end if; if Ekind (Typ) = E_Anonymous_Access_Type then DDT := Directly_Designated_Type (Typ); if Has_Non_Limited_View (DDT) then DDT := Non_Limited_View (DDT); end if; return Is_Class_Wide_Type (DDT) and then Is_Interface (DDT); else return Is_Class_Wide_Type (Typ) and then Is_Interface (Typ); end if; end Is_Class_Wide_Interface_Type; ------------------------- -- 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 this is a call to a predicate function, try to constant -- fold it. if Nkind (Call_Node) = N_Function_Call and then Is_Entity_Name (Name (Call_Node)) and then Is_Predicate_Function (Subp) and then Can_Fold_Predicate_Call (Subp) then return; 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 -- 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_Interface_Type (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 (Get_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 (Get_Accessibility (Parm_Ent), Loc), EF => Get_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 (Get_Accessibility (Parm_Ent)) then Add_Extra_Actual (Expr => New_Occurrence_Of (Get_Accessibility (Parm_Ent), Loc), EF => Get_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 => Get_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 => Get_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 => Get_Accessibility (Formal)); -- All other cases else case Nkind (Prev_Orig) is when N_Attribute_Reference => case Get_Attribute_Id (Attribute_Name (Prev_Orig)) is -- Ignore 'Result, 'Loop_Entry, and 'Old as they can -- be used to identify access objects and do not have -- an effect on accessibility level. when Attribute_Loop_Entry | Attribute_Old | Attribute_Result => null; -- 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 => Get_Accessibility (Formal)); elsif Nkind (Prev_Orig) = N_Explicit_Dereference and then Present (Pref_Entity) and then Is_Formal (Pref_Entity) and then Present (Get_Accessibility (Pref_Entity)) then Add_Extra_Actual (Expr => New_Occurrence_Of (Get_Accessibility (Pref_Entity), Loc), EF => Get_Accessibility (Formal)); else Add_Extra_Actual (Expr => Make_Integer_Literal (Loc, Intval => Object_Access_Level (Prev_Orig)), EF => Get_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 => Get_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. However, according to RM 3.10.2(14/3) this -- is wrong since for an anonymous allocator defining the -- value of an access parameter, the accessibility level is -- that of the innermost master of the call??? when N_Allocator => Add_Extra_Actual (Expr => Make_Integer_Literal (Loc, Intval => Scope_Depth (Current_Scope) + 1), EF => Get_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 => Get_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 Is_Assignable (Ent) then Sav := Last_Assignment (Ent); Kill_Current_Values (Ent); Set_Last_Assignment (Ent, Sav); Set_Is_Known_Valid (Ent, False); Set_Is_True_Constant (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; -- Front-end inlining of expression functions (performed also when -- back-end inlining is enabled). elsif Is_Inlinable_Expression_Function (Subp) then Rewrite (N, New_Copy (Expression_Of_Expression_Function (Subp))); Analyze (N); return; -- Handle front-end 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; -- 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 below, 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. elsif Present (Unit_Declaration_Node (Subp)) and then Nkind (Unit_Declaration_Node (Subp)) = N_Subprogram_Declaration and then Present (Body_To_Inline (Unit_Declaration_Node (Subp))) and then Nkind (Body_To_Inline (Unit_Declaration_Node (Subp))) not in N_Entity then Expand_Inlined_Call (Call_Node, Subp, Orig_Subp); -- Back-end inlining either if optimization is enabled or the call is -- required to be inlined. elsif Optimization_Level > 0 or else Has_Pragma_Inline_Always (Subp) then Add_Inlined_Body (Subp, Call_Node); 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) and then (Ekind (Current_Scope) /= E_Loop or else Nkind (Parent (N)) /= N_Function_Call or else not Is_Build_In_Place_Function_Call (Parent (N))) then Establish_Transient_Scope (Call_Node, Manage_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_Or_Pool_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 -- heap or user-defined storage pool. The object may need finalization -- actions depending on the return type. -- -- * Controlled case -- -- if BIPfinalizationmaster = null then -- Temp_Id := <Alloc_Expr>; -- else -- 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; -- -- * Non-controlled case -- -- Temp_Id := <Alloc_Expr>; -- -- 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_Or_Pool_Allocator -- ---------------------------------- function Build_Heap_Or_Pool_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 objects that require finalization actions 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); Orig_Expr : constant Node_Id := New_Copy_Tree (Source => Alloc_Expr, Scopes_In_EWA_OK => True); 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 -- Temp_Id := <Orig_Expr>; -- else -- declare -- <Decls> -- begin -- <Stmts> -- end; -- end if; return Make_If_Statement (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Occurrence_Of (Fin_Mas_Id, Loc), Right_Opnd => Make_Null (Loc)), Then_Statements => New_List ( Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Temp_Id, Loc), Expression => Orig_Expr)), Else_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_Or_Pool_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; Stmts : List_Id; Return_Stmt : Node_Id := Empty; -- Force initialization to facilitate static analysis -- 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_Subprogram)); if Nkind (Ret_Obj_Decl) = N_Object_Declaration then Exp := Expression (Ret_Obj_Decl); -- Assert that if F says "return R : T := G(...) do..." -- then F and G are both b-i-p, or neither b-i-p. if Nkind (Exp) = N_Function_Call then pragma Assert (Ekind (Current_Subprogram) = E_Function); pragma Assert (Is_Build_In_Place_Function (Current_Subprogram) = Is_Build_In_Place_Function_Call (Exp)); null; end if; 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 (Source => Ret_Obj_Expr, Scopes_In_EWA_OK => True)); 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, tagged, and controlled result subtypes). if not Needs_BIP_Alloc_Form (Func_Id) then Insert_After (Ret_Obj_Decl, Init_Assignment); end if; end if; -- When the function's subtype is unconstrained, a run-time -- test may be needed to decide 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 Needs_BIP_Alloc_Form (Func_Id) 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; Guard_Except : 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 -- 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 (Source => Ret_Obj_Expr, Scopes_In_EWA_OK => True))); 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 (Source => Heap_Allocator, Scopes_In_EWA_OK => True); 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 (Source => Heap_Allocator, Scopes_In_EWA_OK => True); 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 Check_Restriction (No_Secondary_Stack, N); 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); -- Guard against poor expansion on the caller side by -- using a raise statement to catch out-of-range values -- of formal parameter BIP_Alloc_Form. if Exceptions_OK then Guard_Except := Make_Raise_Program_Error (Loc, Reason => PE_Build_In_Place_Mismatch); else Guard_Except := Make_Null_Statement (Loc); end if; -- 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_Or_Pool_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_Or_Pool_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. Else_Statements => New_List (Guard_Except)); -- 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))); pragma Assert (Assignment_OK (Original_Node (Name (Init_Assignment)))); Set_Assignment_OK (Name (Init_Assignment)); 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; -- When the function's subtype is unconstrained and a run-time -- test is not needed, we nevertheless need to build the return -- using the function's result subtype. elsif not Is_Constrained (Underlying_Type (Etype (Func_Id))) then declare Alloc_Obj_Id : Entity_Id; Alloc_Obj_Decl : Node_Id; Ptr_Type_Decl : Node_Id; Ref_Type : Entity_Id; begin -- 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 initialized to the conversion -- of the implicit access value passed in by the caller. Alloc_Obj_Id := Make_Temporary (Loc, 'R'); Set_Etype (Alloc_Obj_Id, Ref_Type); -- See the ??? comment a few lines above about the use of -- an unchecked conversion here. Alloc_Obj_Decl := Make_Object_Declaration (Loc, Defining_Identifier => Alloc_Obj_Id, Object_Definition => New_Occurrence_Of (Ref_Type, Loc), Expression => Make_Unchecked_Type_Conversion (Loc, Subtype_Mark => New_Occurrence_Of (Ref_Type, Loc), Expression => New_Occurrence_Of (Obj_Acc_Formal, Loc))); Insert_Before (Ret_Obj_Decl, Alloc_Obj_Decl); -- 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, Suppress => All_Checks); 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 -- interfere with analysis, e.g. by CodePeer. We also don't need these -- if we're unnesting subprograms because the only purpose of these -- nodes is to ensure we don't set a label in one subprogram and branch -- to it in another. 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 not Unnest_Subprogram_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)); -- A default parameter of a protected operation may be a call to -- a protected function of the type. This appears as an internal -- call in the profile of the operation, but if the context is an -- external call we must convert the call into an external one, -- using the protected object that is the target, so that: -- Prot.P (F) -- is transformed into -- Prot.P (Prot.F) elsif Nkind (Parent (N)) = N_Procedure_Call_Statement and then Nkind (Name (Parent (N))) = N_Selected_Component and then Is_Protected_Type (Etype (Prefix (Name (Parent (N))))) and then Is_Entity_Name (Name (N)) and then Scope (Entity (Name (N))) = Etype (Prefix (Name (Parent (N)))) then Rewrite (Name (N), Make_Selected_Component (Sloc (N), Prefix => New_Copy_Tree (Prefix (Name (Parent (N)))), Selector_Name => Relocate_Node (Name (N)))); Analyze_And_Resolve (N); return; 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; -- Assert that if F says "return G(...);" -- then F and G are both b-i-p, or neither b-i-p. if Nkind (Exp) = N_Function_Call then pragma Assert (Ekind (Scope_Id) = E_Function); pragma Assert (Is_Build_In_Place_Function (Scope_Id) = Is_Build_In_Place_Function_Call (Exp)); null; 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; -- A return statement from an ignored Ghost function does not use the -- secondary stack (or any other one). elsif not Requires_Transient_Scope (R_Type) or else Is_Ignored_Ghost_Entity (Scope_Id) 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. -- We must also verify an underlying type exists for the return type in -- case it is incomplete - in which case is not necessary to generate a -- check anyway since an incomplete limited tagged return type would -- qualify as a premature usage. if Present (Utyp) and then 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 Is_Formal (Entity (Exp)))) 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 Is_Formal (Entity (Exp))) 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; 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 a nonscalar object that is possibly unaligned, -- 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) and then not Represented_As_Scalar (Etype (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; ----------------------- -- 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, Iface => Related_Type (Node (Iface_DT_Ptr))); 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; -------------------------------------------- -- 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; ------------------------------ -- 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_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 with more controlled types. Eventually, we might -- 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. if Ekind_In (E, E_Function, E_Generic_Function) or else (Ekind (E) = E_Subprogram_Type and then Etype (E) /= Standard_Void_Type) then -- If the function is imported from a foreign language, we don't do -- build-in-place. Note that Import (Ada) functions can do -- build-in-place. Note that it is OK for a build-in-place function -- to return a type with a foreign convention; the build-in-place -- machinery will ensure there is no copying. return Is_Build_In_Place_Result_Type (Etype (E)) and then not (Has_Foreign_Convention (E) and then Is_Imported (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; ----------------------- -- 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 created -- on the caller side, and access to it is passed to the function. This -- optimization is disabled when the result subtype needs finalization -- actions because the caller side allocation may result in undesirable -- finalization. Consider the following example: -- -- function Make_Lim_Ctrl return Lim_Ctrl is -- begin -- return Result : Lim_Ctrl := raise Program_Error do -- null; -- end return; -- end Make_Lim_Ctrl; -- -- Obj : Lim_Ctrl_Ptr := new Lim_Ctrl'(Make_Lim_Ctrl); -- -- Even though the size of limited controlled type Lim_Ctrl is known, -- allocating Obj at the caller side will chain Obj on Lim_Ctrl_Ptr's -- finalization master. The subsequent call to Make_Lim_Ctrl will fail -- during the initialization actions for Result, which implies that -- Result (and Obj by extension) should not be finalized. However Obj -- will be finalized when access type Lim_Ctrl_Ptr goes out of scope -- since it is already attached on the related finalization master. -- 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 the -- one in the function body, and the expansion mechanism depends on -- the characteristics of the full view. if Needs_BIP_Alloc_Form (Function_Id) then 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; else -- 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. 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); pragma Assert (Check_Number_Of_Actuals (Func_Call, Function_Id)); 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)); pragma Assert (Check_Number_Of_Actuals (Func_Call, Function_Id)); -- 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); pragma Assert (Check_Number_Of_Actuals (Func_Call, Function_Id)); 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)); pragma Assert (Check_Number_Of_Actuals (Func_Call, Func_Id)); 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 -- The presence of an address clause complicates the build-in-place -- expansion because the indicated address must be processed before -- the indirect call is generated (including the definition of a -- local pointer to the object). The address clause may come from -- an aspect specification or from an explicit attribute -- specification appearing after the object declaration. These two -- cases require different processing. if Has_Aspect (Obj_Def_Id, Aspect_Address) then -- Skip non-delayed pragmas that correspond to other aspects, if -- any, to find proper insertion point for freeze node of object. declare D : Node_Id := Obj_Decl; N : Node_Id := Next (D); begin while Present (N) and then Nkind_In (N, N_Attribute_Reference, N_Pragma) loop Analyze (N); D := N; Next (N); end loop; Insert_After (D, Ptr_Typ_Decl); -- Freeze object before pointer declaration, to ensure that -- generated attribute for address is inserted at the proper -- place. Freeze_Before (Ptr_Typ_Decl, Obj_Def_Id); end; Analyze (Ptr_Typ_Decl); elsif Present (Following_Address_Clause (Obj_Decl)) then -- Locate explicit address clause, which may also follow pragmas -- generated by other aspect specifications. declare Addr : constant Node_Id := Following_Address_Clause (Obj_Decl); D : Node_Id := Next (Obj_Decl); begin while Present (D) loop Analyze (D); exit when D = Addr; Next (D); end loop; Insert_After_And_Analyze (Addr, Ptr_Typ_Decl); end; else Insert_After_And_Analyze (Obj_Decl, Ptr_Typ_Decl); end if; 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, Manage_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 Needs_BIP_Task_Actuals (Function_Id) 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; pragma Assert (Check_Number_Of_Actuals (Func_Call, Function_Id)); 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_Task_Actuals -- ---------------------------- function Needs_BIP_Task_Actuals (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 Has_Task (Func_Typ); end Needs_BIP_Task_Actuals; ----------------------------------- -- 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 Requires_Transient_Scope (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; Disable_Coextension_Cases : constant Boolean := True; -- Flag used to temporarily disable a "True" result for types with -- access discriminants and related coextension cases. -- 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; -- 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; -- Handle the situation where a result is an anonymous access type -- RM 3.10.2 (10.3/3). elsif Ekind (Func_Typ) = E_Anonymous_Access_Type then return True; -- The following cases are related to coextensions and do not fully -- cover everything mentioned in RM 3.10.2 (12) ??? -- Temporarily disabled ??? elsif Disable_Coextension_Cases then return False; -- In the case of, say, a null tagged record result type, the need for -- this extra parameter might not be obvious so 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. elsif Is_Tagged_Type (Func_Typ) then 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 Link_Entities (New_Id, Next_Entity (Orig_Id)); Link_Entities (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;