------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ P R A G -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2005 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 2, 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 COPYING. If not, write -- -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- 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 Casing; use Casing; with Einfo; use Einfo; with Errout; use Errout; with Exp_Ch11; use Exp_Ch11; with Exp_Tss; use Exp_Tss; with Exp_Util; use Exp_Util; with Expander; use Expander; with Namet; use Namet; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Util; use Sem_Util; with Sinfo; use Sinfo; with Sinput; use Sinput; with Snames; use Snames; with Stringt; use Stringt; with Stand; use Stand; with Targparm; use Targparm; with Tbuild; use Tbuild; with Uintp; use Uintp; package body Exp_Prag is ----------------------- -- Local Subprograms -- ----------------------- function Arg1 (N : Node_Id) return Node_Id; function Arg2 (N : Node_Id) return Node_Id; -- Obtain specified pragma argument expression procedure Expand_Pragma_Abort_Defer (N : Node_Id); procedure Expand_Pragma_Assert (N : Node_Id); procedure Expand_Pragma_Common_Object (N : Node_Id); procedure Expand_Pragma_Import (N : Node_Id); procedure Expand_Pragma_Import_Export_Exception (N : Node_Id); procedure Expand_Pragma_Inspection_Point (N : Node_Id); procedure Expand_Pragma_Interrupt_Priority (N : Node_Id); procedure Expand_Pragma_Psect_Object (N : Node_Id); ---------- -- Arg1 -- ---------- function Arg1 (N : Node_Id) return Node_Id is Arg : constant Node_Id := First (Pragma_Argument_Associations (N)); begin if Present (Arg) and then Nkind (Arg) = N_Pragma_Argument_Association then return Expression (Arg); else return Arg; end if; end Arg1; ---------- -- Arg2 -- ---------- function Arg2 (N : Node_Id) return Node_Id is Arg1 : constant Node_Id := First (Pragma_Argument_Associations (N)); begin if No (Arg1) then return Empty; else declare Arg : constant Node_Id := Next (Arg1); begin if Present (Arg) and then Nkind (Arg) = N_Pragma_Argument_Association then return Expression (Arg); else return Arg; end if; end; end if; end Arg2; --------------------- -- Expand_N_Pragma -- --------------------- procedure Expand_N_Pragma (N : Node_Id) is begin -- Note: we may have a pragma whose chars field is not a -- recognized pragma, and we must ignore it at this stage. if Is_Pragma_Name (Chars (N)) then case Get_Pragma_Id (Chars (N)) is -- Pragmas requiring special expander action when Pragma_Abort_Defer => Expand_Pragma_Abort_Defer (N); when Pragma_Assert => Expand_Pragma_Assert (N); when Pragma_Common_Object => Expand_Pragma_Common_Object (N); when Pragma_Export_Exception => Expand_Pragma_Import_Export_Exception (N); when Pragma_Import => Expand_Pragma_Import (N); when Pragma_Import_Exception => Expand_Pragma_Import_Export_Exception (N); when Pragma_Inspection_Point => Expand_Pragma_Inspection_Point (N); when Pragma_Interrupt_Priority => Expand_Pragma_Interrupt_Priority (N); when Pragma_Psect_Object => Expand_Pragma_Psect_Object (N); -- All other pragmas need no expander action when others => null; end case; end if; end Expand_N_Pragma; ------------------------------- -- Expand_Pragma_Abort_Defer -- ------------------------------- -- An Abort_Defer pragma appears as the first statement in a handled -- statement sequence (right after the begin). It defers aborts for -- the entire statement sequence, but not for any declarations or -- handlers (if any) associated with this statement sequence. -- The transformation is to transform -- pragma Abort_Defer; -- statements; -- into -- begin -- Abort_Defer.all; -- statements -- exception -- when all others => -- Abort_Undefer.all; -- raise; -- at end -- Abort_Undefer_Direct; -- end; procedure Expand_Pragma_Abort_Defer (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Stm : Node_Id; Stms : List_Id; HSS : Node_Id; Blk : constant Entity_Id := New_Internal_Entity (E_Block, Current_Scope, Sloc (N), 'B'); begin Stms := New_List (Build_Runtime_Call (Loc, RE_Abort_Defer)); loop Stm := Remove_Next (N); exit when No (Stm); Append (Stm, Stms); end loop; HSS := Make_Handled_Sequence_Of_Statements (Loc, Statements => Stms, At_End_Proc => New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc)); Rewrite (N, Make_Block_Statement (Loc, Handled_Statement_Sequence => HSS)); Set_Scope (Blk, Current_Scope); Set_Etype (Blk, Standard_Void_Type); Set_Identifier (N, New_Occurrence_Of (Blk, Sloc (N))); Expand_At_End_Handler (HSS, Blk); Analyze (N); end Expand_Pragma_Abort_Defer; -------------------------- -- Expand_Pragma_Assert -- -------------------------- procedure Expand_Pragma_Assert (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Cond : constant Node_Id := Arg1 (N); Msg : String_Id; begin -- We already know that assertions are enabled, because otherwise -- the semantic pass dealt with rewriting the assertion (see Sem_Prag) pragma Assert (Assertions_Enabled); -- Since assertions are on, we rewrite the pragma with its -- corresponding if statement, and then analyze the statement -- The expansion transforms: -- pragma Assert (condition [,message]); -- into -- if not condition then -- System.Assertions.Raise_Assert_Failure (Str); -- end if; -- where Str is the message if one is present, or the default of -- file:line if no message is given. -- First, we need to prepare the character literal if Present (Arg2 (N)) then Msg := Strval (Expr_Value_S (Arg2 (N))); else Build_Location_String (Loc); Msg := String_From_Name_Buffer; end if; -- Now generate the if statement. Note that we consider this to be -- an explicit conditional in the source, not an implicit if, so we -- do not call Make_Implicit_If_Statement. Rewrite (N, Make_If_Statement (Loc, Condition => Make_Op_Not (Loc, Right_Opnd => Cond), Then_Statements => New_List ( Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Raise_Assert_Failure), Loc), Parameter_Associations => New_List ( Make_String_Literal (Loc, Msg)))))); Analyze (N); -- If new condition is always false, give a warning if Nkind (N) = N_Procedure_Call_Statement and then Is_RTE (Entity (Name (N)), RE_Raise_Assert_Failure) then -- If original condition was a Standard.False, we assume -- that this is indeed intented to raise assert error -- and no warning is required. if Is_Entity_Name (Original_Node (Cond)) and then Entity (Original_Node (Cond)) = Standard_False then return; else Error_Msg_N ("?assertion will fail at run-time", N); end if; end if; end Expand_Pragma_Assert; --------------------------------- -- Expand_Pragma_Common_Object -- --------------------------------- -- Add series of pragmas to replicate semantic effect in DEC Ada -- pragma Linker_Section (internal_name, external_name); -- pragma Machine_Attribute (internal_name, "overlaid"); -- pragma Machine_Attribute (internal_name, "global"); -- pragma Machine_Attribute (internal_name, "initialize"); -- For now we do nothing with the size attribute ??? -- Really this expansion would be much better in the back end. The -- front end should not need to know about target dependent, back end -- dependent semantics ??? procedure Expand_Pragma_Common_Object (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Internal : constant Node_Id := Arg1 (N); External : constant Node_Id := Arg2 (N); Psect : Node_Id; -- Psect value upper cased as string literal Iloc : constant Source_Ptr := Sloc (Internal); Eloc : constant Source_Ptr := Sloc (External); Ploc : Source_Ptr; begin -- Acquire Psect value and fold to upper case if Present (External) then if Nkind (External) = N_String_Literal then String_To_Name_Buffer (Strval (External)); else Get_Name_String (Chars (External)); end if; Set_All_Upper_Case; Psect := Make_String_Literal (Eloc, Strval => String_From_Name_Buffer); else Get_Name_String (Chars (Internal)); Set_All_Upper_Case; Psect := Make_String_Literal (Iloc, Strval => String_From_Name_Buffer); end if; Ploc := Sloc (Psect); -- Insert pragmas Insert_List_After_And_Analyze (N, New_List ( -- The Linker_Section pragma ensures the correct section Make_Pragma (Loc, Chars => Name_Linker_Section, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Iloc, Expression => New_Copy_Tree (Internal)), Make_Pragma_Argument_Association (Ploc, Expression => New_Copy_Tree (Psect)))), -- Machine_Attribute "overlaid" ensures that this section -- overlays any other sections of the same name. Make_Pragma (Loc, Chars => Name_Machine_Attribute, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Iloc, Expression => New_Copy_Tree (Internal)), Make_Pragma_Argument_Association (Eloc, Expression => Make_String_Literal (Sloc => Ploc, Strval => "overlaid")))), -- Machine_Attribute "global" ensures that section is visible Make_Pragma (Loc, Chars => Name_Machine_Attribute, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Iloc, Expression => New_Copy_Tree (Internal)), Make_Pragma_Argument_Association (Eloc, Expression => Make_String_Literal (Sloc => Ploc, Strval => "global")))), -- Machine_Attribute "initialize" ensures section is demand zeroed Make_Pragma (Loc, Chars => Name_Machine_Attribute, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Iloc, Expression => New_Copy_Tree (Internal)), Make_Pragma_Argument_Association (Eloc, Expression => Make_String_Literal (Sloc => Ploc, Strval => "initialize")))))); end Expand_Pragma_Common_Object; -------------------------- -- Expand_Pragma_Import -- -------------------------- -- When applied to a variable, the default initialization must not be -- done. As it is already done when the pragma is found, we just get rid -- of the call the initialization procedure which followed the object -- declaration. The call is inserted after the declaration, but validity -- checks may also have been inserted and the initialization call does -- not necessarily appear immediately after the object declaration. -- We can't use the freezing mechanism for this purpose, since we -- have to elaborate the initialization expression when it is first -- seen (i.e. this elaboration cannot be deferred to the freeze point). procedure Expand_Pragma_Import (N : Node_Id) is Def_Id : constant Entity_Id := Entity (Arg2 (N)); Typ : Entity_Id; Init_Call : Node_Id; begin if Ekind (Def_Id) = E_Variable then Typ := Etype (Def_Id); -- Loop to ??? Init_Call := Next (Parent (Def_Id)); while Present (Init_Call) and then Init_Call /= N loop if Has_Non_Null_Base_Init_Proc (Typ) and then Nkind (Init_Call) = N_Procedure_Call_Statement and then Is_Entity_Name (Name (Init_Call)) and then Entity (Name (Init_Call)) = Base_Init_Proc (Typ) then Remove (Init_Call); exit; else Next (Init_Call); end if; end loop; -- Any default initialization expression should be removed -- (e.g., null defaults for access objects, zero initialization -- of packed bit arrays). Imported objects aren't allowed to -- have explicit initialization, so the expression must have -- been generated by the compiler. if No (Init_Call) and then Present (Expression (Parent (Def_Id))) then Set_Expression (Parent (Def_Id), Empty); end if; end if; end Expand_Pragma_Import; ------------------------------------------- -- Expand_Pragma_Import_Export_Exception -- ------------------------------------------- -- For a VMS exception fix up the language field with "VMS" -- instead of "Ada" (gigi needs this), create a constant that will be the -- value of the VMS condition code and stuff the Interface_Name field -- with the unexpanded name of the exception (if not already set). -- For a Ada exception, just stuff the Interface_Name field -- with the unexpanded name of the exception (if not already set). procedure Expand_Pragma_Import_Export_Exception (N : Node_Id) is begin -- This pragma is only effective on OpenVMS systems, it was ignored -- on non-VMS systems, and we need to ignore it here as well. if not OpenVMS_On_Target then return; end if; declare Id : constant Entity_Id := Entity (Arg1 (N)); Call : constant Node_Id := Register_Exception_Call (Id); Loc : constant Source_Ptr := Sloc (N); begin if Present (Call) then declare Excep_Internal : constant Node_Id := Make_Defining_Identifier (Loc, New_Internal_Name ('V')); Export_Pragma : Node_Id; Excep_Alias : Node_Id; Excep_Object : Node_Id; Excep_Image : String_Id; Exdata : List_Id; Lang1 : Node_Id; Lang2 : Node_Id; Lang3 : Node_Id; Code : Node_Id; begin if Present (Interface_Name (Id)) then Excep_Image := Strval (Interface_Name (Id)); else Get_Name_String (Chars (Id)); Set_All_Upper_Case; Excep_Image := String_From_Name_Buffer; end if; Exdata := Component_Associations (Expression (Parent (Id))); if Is_VMS_Exception (Id) then Lang1 := Next (First (Exdata)); Lang2 := Next (Lang1); Lang3 := Next (Lang2); Rewrite (Expression (Lang1), Make_Character_Literal (Loc, Chars => Name_uV, Char_Literal_Value => UI_From_Int (Character'Pos ('V')))); Analyze (Expression (Lang1)); Rewrite (Expression (Lang2), Make_Character_Literal (Loc, Chars => Name_uM, Char_Literal_Value => UI_From_Int (Character'Pos ('M')))); Analyze (Expression (Lang2)); Rewrite (Expression (Lang3), Make_Character_Literal (Loc, Chars => Name_uS, Char_Literal_Value => UI_From_Int (Character'Pos ('S')))); Analyze (Expression (Lang3)); if Exception_Code (Id) /= No_Uint then Code := Make_Integer_Literal (Loc, Intval => Exception_Code (Id)); Excep_Object := Make_Object_Declaration (Loc, Defining_Identifier => Excep_Internal, Object_Definition => New_Reference_To (RTE (RE_Exception_Code), Loc)); Insert_Action (N, Excep_Object); Analyze (Excep_Object); Start_String; Store_String_Int (UI_To_Int (Exception_Code (Id)) / 8 * 8); Excep_Alias := Make_Pragma (Loc, Name_Linker_Alias, New_List (Make_Pragma_Argument_Association (Sloc => Loc, Expression => New_Reference_To (Excep_Internal, Loc)), Make_Pragma_Argument_Association (Sloc => Loc, Expression => Make_String_Literal (Sloc => Loc, Strval => End_String)))); Insert_Action (N, Excep_Alias); Analyze (Excep_Alias); Export_Pragma := Make_Pragma (Loc, Name_Export, New_List (Make_Pragma_Argument_Association (Sloc => Loc, Expression => Make_Identifier (Loc, Name_C)), Make_Pragma_Argument_Association (Sloc => Loc, Expression => New_Reference_To (Excep_Internal, Loc)), Make_Pragma_Argument_Association (Sloc => Loc, Expression => Make_String_Literal (Sloc => Loc, Strval => Excep_Image)), Make_Pragma_Argument_Association (Sloc => Loc, Expression => Make_String_Literal (Sloc => Loc, Strval => Excep_Image)))); Insert_Action (N, Export_Pragma); Analyze (Export_Pragma); else Code := Unchecked_Convert_To (RTE (RE_Exception_Code), Make_Function_Call (Loc, Name => New_Reference_To (RTE (RE_Import_Value), Loc), Parameter_Associations => New_List (Make_String_Literal (Loc, Strval => Excep_Image)))); end if; Rewrite (Call, Make_Procedure_Call_Statement (Loc, Name => New_Reference_To (RTE (RE_Register_VMS_Exception), Loc), Parameter_Associations => New_List ( Code, Unchecked_Convert_To (RTE (RE_Exception_Data_Ptr), Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Id, Loc), Attribute_Name => Name_Unrestricted_Access))))); Analyze_And_Resolve (Code, RTE (RE_Exception_Code)); Analyze (Call); end if; if not Present (Interface_Name (Id)) then Set_Interface_Name (Id, Make_String_Literal (Sloc => Loc, Strval => Excep_Image)); end if; end; end if; end; end Expand_Pragma_Import_Export_Exception; ------------------------------------ -- Expand_Pragma_Inspection_Point -- ------------------------------------ -- If no argument is given, then we supply a default argument list that -- includes all objects declared at the source level in all subprograms -- that enclose the inspection point pragma. procedure Expand_Pragma_Inspection_Point (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); A : List_Id; Assoc : Node_Id; S : Entity_Id; E : Entity_Id; begin if No (Pragma_Argument_Associations (N)) then A := New_List; S := Current_Scope; while S /= Standard_Standard loop E := First_Entity (S); while Present (E) loop if Comes_From_Source (E) and then Is_Object (E) and then not Is_Entry_Formal (E) and then Ekind (E) /= E_Component and then Ekind (E) /= E_Discriminant and then Ekind (E) /= E_Generic_In_Parameter and then Ekind (E) /= E_Generic_In_Out_Parameter then Append_To (A, Make_Pragma_Argument_Association (Loc, Expression => New_Occurrence_Of (E, Loc))); end if; Next_Entity (E); end loop; S := Scope (S); end loop; Set_Pragma_Argument_Associations (N, A); end if; -- Expand the arguments of the pragma. Expanding an entity reference -- is a noop, except in a protected operation, where a reference may -- have to be transformed into a reference to the corresponding prival. -- Are there other pragmas that may require this ??? Assoc := First (Pragma_Argument_Associations (N)); while Present (Assoc) loop Expand (Expression (Assoc)); Next (Assoc); end loop; end Expand_Pragma_Inspection_Point; -------------------------------------- -- Expand_Pragma_Interrupt_Priority -- -------------------------------------- -- Supply default argument if none exists (System.Interrupt_Priority'Last) procedure Expand_Pragma_Interrupt_Priority (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); begin if No (Pragma_Argument_Associations (N)) then Set_Pragma_Argument_Associations (N, New_List ( Make_Pragma_Argument_Association (Loc, Expression => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (RTE (RE_Interrupt_Priority), Loc), Attribute_Name => Name_Last)))); end if; end Expand_Pragma_Interrupt_Priority; -------------------------------- -- Expand_Pragma_Psect_Object -- -------------------------------- -- Convert to Common_Object, and expand the resulting pragma procedure Expand_Pragma_Psect_Object (N : Node_Id) is begin Set_Chars (N, Name_Common_Object); Expand_Pragma_Common_Object (N); end Expand_Pragma_Psect_Object; end Exp_Prag;