------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- E X P _ P R A G -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992-2014, 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 Casing; use Casing; with Checks; use Checks; with Debug; use Debug; with Einfo; use Einfo; with Errout; use Errout; with Exp_Ch11; use Exp_Ch11; 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 Restrict; use Restrict; with Rident; use Rident; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Ch8; use Sem_Ch8; 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 Tbuild; use Tbuild; with Uintp; use Uintp; with Validsw; use Validsw; package body Exp_Prag is ----------------------- -- Local Subprograms -- ----------------------- function Arg1 (N : Node_Id) return Node_Id; function Arg2 (N : Node_Id) return Node_Id; function Arg3 (N : Node_Id) return Node_Id; -- Obtain specified pragma argument expression procedure Expand_Pragma_Abort_Defer (N : Node_Id); procedure Expand_Pragma_Check (N : Node_Id); procedure Expand_Pragma_Common_Object (N : Node_Id); procedure Expand_Pragma_Import_Or_Interface (N : Node_Id); procedure Expand_Pragma_Inspection_Point (N : Node_Id); procedure Expand_Pragma_Interrupt_Priority (N : Node_Id); procedure Expand_Pragma_Loop_Variant (N : Node_Id); procedure Expand_Pragma_Psect_Object (N : Node_Id); procedure Expand_Pragma_Relative_Deadline (N : Node_Id); procedure Expand_Pragma_Suppress_Initialization (N : Node_Id); procedure Undo_Initialization (Def_Id : Entity_Id; N : Node_Id); -- This procedure is used to undo initialization already done for Def_Id, -- which is always an E_Variable, in response to the occurrence of the -- pragma N, a pragma Interface, Import, or Suppress_Initialization. In all -- these cases we want no initialization to occur, but we have already done -- the initialization by the time we see the pragma, so we have to undo it. ---------- -- 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; ---------- -- Arg3 -- ---------- function Arg3 (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 : Node_Id := Next (Arg1); begin if No (Arg) then return Empty; else Next (Arg); if Present (Arg) and then Nkind (Arg) = N_Pragma_Argument_Association then return Expression (Arg); else return Arg; end if; end if; end; end if; end Arg3; --------------------------- -- Expand_Contract_Cases -- --------------------------- -- Pragma Contract_Cases is expanded in the following manner: -- subprogram S is -- Count : Natural := 0; -- Flag_1 : Boolean := False; -- . . . -- Flag_N : Boolean := False; -- Flag_N+1 : Boolean := False; -- when "others" present -- Pref_1 : ...; -- . . . -- Pref_M : ...; -- -- -- Evaluate all case guards -- if Case_Guard_1 then -- Flag_1 := True; -- Count := Count + 1; -- end if; -- . . . -- if Case_Guard_N then -- Flag_N := True; -- Count := Count + 1; -- end if; -- -- Emit errors depending on the number of case guards that -- -- evaluated to True. -- if Count = 0 then -- raise Assertion_Error with "xxx contract cases incomplete"; -- -- Flag_N+1 := True; -- when "others" present -- elsif Count > 1 then -- declare -- Str0 : constant String := -- "contract cases overlap for subprogram ABC"; -- Str1 : constant String := -- (if Flag_1 then -- Str0 & "case guard at xxx evaluates to True" -- else Str0); -- StrN : constant String := -- (if Flag_N then -- StrN-1 & "case guard at xxx evaluates to True" -- else StrN-1); -- begin -- raise Assertion_Error with StrN; -- end; -- end if; -- -- Evaluate all attribute 'Old prefixes found in the selected -- -- consequence. -- if Flag_1 then -- Pref_1 := -- . . . -- elsif Flag_N then -- Pref_M := -- end if; -- procedure _Postconditions is -- begin -- -- if Flag_1 and then not Consequence_1 then -- raise Assertion_Error with "failed contract case at xxx"; -- end if; -- . . . -- if Flag_N[+1] and then not Consequence_N[+1] then -- raise Assertion_Error with "failed contract case at xxx"; -- end if; -- end _Postconditions; -- begin -- . . . -- end S; procedure Expand_Contract_Cases (CCs : Node_Id; Subp_Id : Entity_Id; Decls : List_Id; Stmts : in out List_Id) is Loc : constant Source_Ptr := Sloc (CCs); procedure Case_Guard_Error (Decls : List_Id; Flag : Entity_Id; Error_Loc : Source_Ptr; Msg : in out Entity_Id); -- Given a declarative list Decls, status flag Flag, the location of the -- error and a string Msg, construct the following check: -- Msg : constant String := -- (if Flag then -- Msg & "case guard at Error_Loc evaluates to True" -- else Msg); -- The resulting code is added to Decls procedure Consequence_Error (Checks : in out Node_Id; Flag : Entity_Id; Conseq : Node_Id); -- Given an if statement Checks, status flag Flag and a consequence -- Conseq, construct the following check: -- [els]if Flag and then not Conseq then -- raise Assertion_Error -- with "failed contract case at Sloc (Conseq)"; -- [end if;] -- The resulting code is added to Checks function Declaration_Of (Id : Entity_Id) return Node_Id; -- Given the entity Id of a boolean flag, generate: -- Id : Boolean := False; procedure Expand_Old_In_Consequence (Decls : List_Id; Evals : in out Node_Id; Flag : Entity_Id; Conseq : Node_Id); -- Perform specialized expansion of all attribute 'Old references found -- in consequence Conseq such that at runtime only prefixes coming from -- the selected consequence are evaluated. Any temporaries generated in -- the process are added to declarative list Decls. Evals is a complex -- if statement tasked with the evaluation of all prefixes coming from -- a selected consequence. Flag is the corresponding case guard flag. -- Conseq is the consequence expression. function Increment (Id : Entity_Id) return Node_Id; -- Given the entity Id of a numerical variable, generate: -- Id := Id + 1; function Set (Id : Entity_Id) return Node_Id; -- Given the entity Id of a boolean variable, generate: -- Id := True; ---------------------- -- Case_Guard_Error -- ---------------------- procedure Case_Guard_Error (Decls : List_Id; Flag : Entity_Id; Error_Loc : Source_Ptr; Msg : in out Entity_Id) is New_Line : constant Character := Character'Val (10); New_Msg : constant Entity_Id := Make_Temporary (Loc, 'S'); begin Start_String; Store_String_Char (New_Line); Store_String_Chars (" case guard at "); Store_String_Chars (Build_Location_String (Error_Loc)); Store_String_Chars (" evaluates to True"); -- Generate: -- New_Msg : constant String := -- (if Flag then -- Msg & "case guard at Error_Loc evaluates to True" -- else Msg); Append_To (Decls, Make_Object_Declaration (Loc, Defining_Identifier => New_Msg, Constant_Present => True, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => Make_If_Expression (Loc, Expressions => New_List ( New_Occurrence_Of (Flag, Loc), Make_Op_Concat (Loc, Left_Opnd => New_Occurrence_Of (Msg, Loc), Right_Opnd => Make_String_Literal (Loc, End_String)), New_Occurrence_Of (Msg, Loc))))); Msg := New_Msg; end Case_Guard_Error; ----------------------- -- Consequence_Error -- ----------------------- procedure Consequence_Error (Checks : in out Node_Id; Flag : Entity_Id; Conseq : Node_Id) is Cond : Node_Id; Error : Node_Id; begin -- Generate: -- Flag and then not Conseq Cond := Make_And_Then (Loc, Left_Opnd => New_Occurrence_Of (Flag, Loc), Right_Opnd => Make_Op_Not (Loc, Right_Opnd => Relocate_Node (Conseq))); -- Generate: -- raise Assertion_Error -- with "failed contract case at Sloc (Conseq)"; Start_String; Store_String_Chars ("failed contract case at "); Store_String_Chars (Build_Location_String (Sloc (Conseq))); Error := Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Raise_Assert_Failure), Loc), Parameter_Associations => New_List ( Make_String_Literal (Loc, End_String))); if No (Checks) then Checks := Make_Implicit_If_Statement (CCs, Condition => Cond, Then_Statements => New_List (Error)); else if No (Elsif_Parts (Checks)) then Set_Elsif_Parts (Checks, New_List); end if; Append_To (Elsif_Parts (Checks), Make_Elsif_Part (Loc, Condition => Cond, Then_Statements => New_List (Error))); end if; end Consequence_Error; -------------------- -- Declaration_Of -- -------------------- function Declaration_Of (Id : Entity_Id) return Node_Id is begin return Make_Object_Declaration (Loc, Defining_Identifier => Id, Object_Definition => New_Occurrence_Of (Standard_Boolean, Loc), Expression => New_Occurrence_Of (Standard_False, Loc)); end Declaration_Of; ------------------------------- -- Expand_Old_In_Consequence -- ------------------------------- procedure Expand_Old_In_Consequence (Decls : List_Id; Evals : in out Node_Id; Flag : Entity_Id; Conseq : Node_Id) is Eval_Stmts : List_Id := No_List; -- The evaluation sequence expressed as assignment statements of all -- prefixes of attribute 'Old found in the current consequence. function Expand_Old (N : Node_Id) return Traverse_Result; -- Determine whether an arbitrary node denotes attribute 'Old and if -- it does, perform all expansion-related actions. ---------------- -- Expand_Old -- ---------------- function Expand_Old (N : Node_Id) return Traverse_Result is Decl : Node_Id; Pref : Node_Id; Temp : Entity_Id; begin if Nkind (N) = N_Attribute_Reference and then Attribute_Name (N) = Name_Old then Pref := Prefix (N); Temp := Make_Temporary (Loc, 'T', Pref); Set_Etype (Temp, Etype (Pref)); -- Generate a temporary to capture the value of the prefix: -- Temp : ; -- Place that temporary at the beginning of declarations, to -- prevent anomalies in the GNATprove flow-analysis pass in -- the precondition procedure that follows. Decl := Make_Object_Declaration (Loc, Defining_Identifier => Temp, Object_Definition => New_Occurrence_Of (Etype (Pref), Loc)); Set_No_Initialization (Decl); Prepend_To (Decls, Decl); -- Evaluate the prefix, generate: -- Temp := ; if No (Eval_Stmts) then Eval_Stmts := New_List; end if; Append_To (Eval_Stmts, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Temp, Loc), Expression => Pref)); -- Ensure that the prefix is valid if Validity_Checks_On and then Validity_Check_Operands then Ensure_Valid (Pref); end if; -- Replace the original attribute 'Old by a reference to the -- generated temporary. Rewrite (N, New_Occurrence_Of (Temp, Loc)); end if; return OK; end Expand_Old; procedure Expand_Olds is new Traverse_Proc (Expand_Old); -- Start of processing for Expand_Old_In_Consequence begin -- Inspect the consequence and expand any attribute 'Old references -- found within. Expand_Olds (Conseq); -- Augment the machinery to trigger the evaluation of all prefixes -- found in the step above. If Eval is empty, then this is the first -- consequence to yield expansion of 'Old. Generate: -- if Flag then -- -- end if; if No (Evals) then Evals := Make_Implicit_If_Statement (CCs, Condition => New_Occurrence_Of (Flag, Loc), Then_Statements => Eval_Stmts); -- Otherwise generate: -- elsif Flag then -- -- end if; else if No (Elsif_Parts (Evals)) then Set_Elsif_Parts (Evals, New_List); end if; Append_To (Elsif_Parts (Evals), Make_Elsif_Part (Loc, Condition => New_Occurrence_Of (Flag, Loc), Then_Statements => Eval_Stmts)); end if; end Expand_Old_In_Consequence; --------------- -- Increment -- --------------- function Increment (Id : Entity_Id) return Node_Id is begin return Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Id, Loc), Expression => Make_Op_Add (Loc, Left_Opnd => New_Occurrence_Of (Id, Loc), Right_Opnd => Make_Integer_Literal (Loc, 1))); end Increment; --------- -- Set -- --------- function Set (Id : Entity_Id) return Node_Id is begin return Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Id, Loc), Expression => New_Occurrence_Of (Standard_True, Loc)); end Set; -- Local variables Aggr : constant Node_Id := Expression (First (Pragma_Argument_Associations (CCs))); Case_Guard : Node_Id; CG_Checks : Node_Id; CG_Stmts : List_Id; Conseq : Node_Id; Conseq_Checks : Node_Id := Empty; Count : Entity_Id; Error_Decls : List_Id; Flag : Entity_Id; Msg_Str : Entity_Id; Multiple_PCs : Boolean; Old_Evals : Node_Id := Empty; Others_Flag : Entity_Id := Empty; Post_Case : Node_Id; -- Start of processing for Expand_Contract_Cases begin -- Do nothing if pragma is not enabled. If pragma is disabled, it has -- already been rewritten as a Null statement. if Is_Ignored (CCs) then return; -- Guard against malformed contract cases elsif Nkind (Aggr) /= N_Aggregate then return; end if; Multiple_PCs := List_Length (Component_Associations (Aggr)) > 1; -- Create the counter which tracks the number of case guards that -- evaluate to True. -- Count : Natural := 0; Count := Make_Temporary (Loc, 'C'); Prepend_To (Decls, Make_Object_Declaration (Loc, Defining_Identifier => Count, Object_Definition => New_Occurrence_Of (Standard_Natural, Loc), Expression => Make_Integer_Literal (Loc, 0))); -- Create the base error message for multiple overlapping case guards -- Msg_Str : constant String := -- "contract cases overlap for subprogram Subp_Id"; if Multiple_PCs then Msg_Str := Make_Temporary (Loc, 'S'); Start_String; Store_String_Chars ("contract cases overlap for subprogram "); Store_String_Chars (Get_Name_String (Chars (Subp_Id))); Error_Decls := New_List ( Make_Object_Declaration (Loc, Defining_Identifier => Msg_Str, Constant_Present => True, Object_Definition => New_Occurrence_Of (Standard_String, Loc), Expression => Make_String_Literal (Loc, End_String))); end if; -- Process individual post cases Post_Case := First (Component_Associations (Aggr)); while Present (Post_Case) loop Case_Guard := First (Choices (Post_Case)); Conseq := Expression (Post_Case); -- The "others" choice requires special processing if Nkind (Case_Guard) = N_Others_Choice then Others_Flag := Make_Temporary (Loc, 'F'); Prepend_To (Decls, Declaration_Of (Others_Flag)); -- Check possible overlap between a case guard and "others" if Multiple_PCs and Exception_Extra_Info then Case_Guard_Error (Decls => Error_Decls, Flag => Others_Flag, Error_Loc => Sloc (Case_Guard), Msg => Msg_Str); end if; -- Inspect the consequence and perform special expansion of any -- attribute 'Old references found within. Expand_Old_In_Consequence (Decls => Decls, Evals => Old_Evals, Flag => Others_Flag, Conseq => Conseq); -- Check the corresponding consequence of "others" Consequence_Error (Checks => Conseq_Checks, Flag => Others_Flag, Conseq => Conseq); -- Regular post case else -- Create the flag which tracks the state of its associated case -- guard. Flag := Make_Temporary (Loc, 'F'); Prepend_To (Decls, Declaration_Of (Flag)); -- The flag is set when the case guard is evaluated to True -- if Case_Guard then -- Flag := True; -- Count := Count + 1; -- end if; Append_To (Decls, Make_Implicit_If_Statement (CCs, Condition => Relocate_Node (Case_Guard), Then_Statements => New_List ( Set (Flag), Increment (Count)))); -- Check whether this case guard overlaps with another one if Multiple_PCs and Exception_Extra_Info then Case_Guard_Error (Decls => Error_Decls, Flag => Flag, Error_Loc => Sloc (Case_Guard), Msg => Msg_Str); end if; -- Inspect the consequence and perform special expansion of any -- attribute 'Old references found within. Expand_Old_In_Consequence (Decls => Decls, Evals => Old_Evals, Flag => Flag, Conseq => Conseq); -- The corresponding consequence of the case guard which evaluated -- to True must hold on exit from the subprogram. Consequence_Error (Checks => Conseq_Checks, Flag => Flag, Conseq => Conseq); end if; Next (Post_Case); end loop; -- Raise Assertion_Error when none of the case guards evaluate to True. -- The only exception is when we have "others", in which case there is -- no error because "others" acts as a default True. -- Generate: -- Flag := True; if Present (Others_Flag) then CG_Stmts := New_List (Set (Others_Flag)); -- Generate: -- raise Assertion_Error with "xxx contract cases incomplete"; else Start_String; Store_String_Chars (Build_Location_String (Loc)); Store_String_Chars (" contract cases incomplete"); CG_Stmts := New_List ( Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Raise_Assert_Failure), Loc), Parameter_Associations => New_List ( Make_String_Literal (Loc, End_String)))); end if; CG_Checks := Make_Implicit_If_Statement (CCs, Condition => Make_Op_Eq (Loc, Left_Opnd => New_Occurrence_Of (Count, Loc), Right_Opnd => Make_Integer_Literal (Loc, 0)), Then_Statements => CG_Stmts); -- Detect a possible failure due to several case guards evaluating to -- True. -- Generate: -- elsif Count > 0 then -- declare -- -- begin -- raise Assertion_Error with ; -- end if; if Multiple_PCs then Set_Elsif_Parts (CG_Checks, New_List ( Make_Elsif_Part (Loc, Condition => Make_Op_Gt (Loc, Left_Opnd => New_Occurrence_Of (Count, Loc), Right_Opnd => Make_Integer_Literal (Loc, 1)), Then_Statements => New_List ( Make_Block_Statement (Loc, Declarations => Error_Decls, Handled_Statement_Sequence => Make_Handled_Sequence_Of_Statements (Loc, Statements => New_List ( Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Raise_Assert_Failure), Loc), Parameter_Associations => New_List ( New_Occurrence_Of (Msg_Str, Loc)))))))))); end if; Append_To (Decls, CG_Checks); -- Once all case guards are evaluated and checked, evaluate any prefixes -- of attribute 'Old founds in the selected consequence. Append_To (Decls, Old_Evals); -- Raise Assertion_Error when the corresponding consequence of a case -- guard that evaluated to True fails. if No (Stmts) then Stmts := New_List; end if; Append_To (Stmts, Conseq_Checks); end Expand_Contract_Cases; --------------------- -- Expand_N_Pragma -- --------------------- procedure Expand_N_Pragma (N : Node_Id) is Pname : constant Name_Id := Pragma_Name (N); begin -- Note: we may have a pragma whose Pragma_Identifier field is not a -- recognized pragma, and we must ignore it at this stage. if Is_Pragma_Name (Pname) then case Get_Pragma_Id (Pname) is -- Pragmas requiring special expander action when Pragma_Abort_Defer => Expand_Pragma_Abort_Defer (N); when Pragma_Check => Expand_Pragma_Check (N); when Pragma_Common_Object => Expand_Pragma_Common_Object (N); when Pragma_Import => Expand_Pragma_Import_Or_Interface (N); when Pragma_Inspection_Point => Expand_Pragma_Inspection_Point (N); when Pragma_Interface => Expand_Pragma_Import_Or_Interface (N); when Pragma_Interrupt_Priority => Expand_Pragma_Interrupt_Priority (N); when Pragma_Loop_Variant => Expand_Pragma_Loop_Variant (N); when Pragma_Psect_Object => Expand_Pragma_Psect_Object (N); when Pragma_Relative_Deadline => Expand_Pragma_Relative_Deadline (N); when Pragma_Suppress_Initialization => Expand_Pragma_Suppress_Initialization (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_Check -- -------------------------- procedure Expand_Pragma_Check (N : Node_Id) is Cond : constant Node_Id := Arg2 (N); Nam : constant Name_Id := Chars (Arg1 (N)); Msg : Node_Id; Loc : constant Source_Ptr := Sloc (First_Node (Cond)); -- Source location used in the case of a failed assertion: point to the -- failing condition, not Loc. Note that the source location of the -- expression is not usually the best choice here, because it points to -- the location of the topmost tree node, which may be an operator in -- the middle of the source text of the expression. For example, it gets -- located on the last AND keyword in a chain of boolean expressiond -- AND'ed together. It is best to put the message on the first character -- of the condition, which is the effect of the First_Node call here. -- This source location is used to build the default exception message, -- and also as the sloc of the call to the runtime subprogram raising -- Assert_Failure, so that coverage analysis tools can relate the -- call to the failed check. begin -- Nothing to do if pragma is ignored if Is_Ignored (N) then return; end if; -- Since this check is active, we rewrite the pragma into a -- corresponding if statement, and then analyze the statement -- The normal case expansion transforms: -- pragma Check (name, 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 -- name failed at file:line if no message is given (the "name failed -- at" is omitted for name = Assertion, since it is redundant, given -- that the name of the exception is Assert_Failure.) -- Also, instead of "XXX failed at", we generate slightly -- different messages for some of the contract assertions (see -- code below for details). -- An alternative expansion is used when the No_Exception_Propagation -- restriction is active and there is a local Assert_Failure handler. -- This is not a common combination of circumstances, but it occurs in -- the context of Aunit and the zero footprint profile. In this case we -- generate: -- if not condition then -- raise Assert_Failure; -- end if; -- This will then be transformed into a goto, and the local handler will -- be able to handle the assert error (which would not be the case if a -- call is made to the Raise_Assert_Failure procedure). -- We also generate the direct raise if the Suppress_Exception_Locations -- is active, since we don't want to generate messages in this case. -- Note that the reason we do not always generate a direct raise is that -- the form in which the procedure is called allows for more efficient -- breakpointing of assertion errors. -- Generate the appropriate 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. -- Case where we generate a direct raise if ((Debug_Flag_Dot_G or else Restriction_Active (No_Exception_Propagation)) and then Present (Find_Local_Handler (RTE (RE_Assert_Failure), N))) or else (Opt.Exception_Locations_Suppressed and then No (Arg3 (N))) then Rewrite (N, Make_If_Statement (Loc, Condition => Make_Op_Not (Loc, Right_Opnd => Cond), Then_Statements => New_List ( Make_Raise_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Assert_Failure), Loc))))); -- Case where we call the procedure else -- If we have a message given, use it if Present (Arg3 (N)) then Msg := Get_Pragma_Arg (Arg3 (N)); -- Here we have no string, so prepare one else declare Loc_Str : constant String := Build_Location_String (Loc); begin Name_Len := 0; -- For Assert, we just use the location if Nam = Name_Assert then null; -- For predicate, we generate the string "predicate failed -- at yyy". We prefer all lower case for predicate. elsif Nam = Name_Predicate then Add_Str_To_Name_Buffer ("predicate failed at "); -- For special case of Precondition/Postcondition the string is -- "failed xx from yy" where xx is precondition/postcondition -- in all lower case. The reason for this different wording is -- that the failure is not at the point of occurrence of the -- pragma, unlike the other Check cases. elsif Nam_In (Nam, Name_Precondition, Name_Postcondition) then Get_Name_String (Nam); Insert_Str_In_Name_Buffer ("failed ", 1); Add_Str_To_Name_Buffer (" from "); -- For special case of Invariant, the string is "failed -- invariant from yy", to be consistent with the string that is -- generated for the aspect case (the code later on checks for -- this specific string to modify it in some cases, so this is -- functionally important). elsif Nam = Name_Invariant then Add_Str_To_Name_Buffer ("failed invariant from "); -- For all other checks, the string is "xxx failed at yyy" -- where xxx is the check name with current source file casing. else Get_Name_String (Nam); Set_Casing (Identifier_Casing (Current_Source_File)); Add_Str_To_Name_Buffer (" failed at "); end if; -- In all cases, add location string Add_Str_To_Name_Buffer (Loc_Str); -- Build the message Msg := Make_String_Literal (Loc, Name_Buffer (1 .. Name_Len)); end; end if; -- Now rewrite as an 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_Occurrence_Of (RTE (RE_Raise_Assert_Failure), Loc), Parameter_Associations => New_List (Relocate_Node (Msg)))))); end if; Analyze (N); -- If new condition is always false, give a warning if Warn_On_Assertion_Failure and then 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 intended 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; elsif Nam = Name_Assert then Error_Msg_N ("?A?assertion will fail at run time", N); else Error_Msg_N ("?A?check will fail at run time", N); end if; end if; end Expand_Pragma_Check; --------------------------------- -- Expand_Pragma_Common_Object -- --------------------------------- -- Use a machine attribute to replicate semantic effect in DEC Ada -- pragma Machine_Attribute (intern_name, "common_object", extern_name); -- For now we do nothing with the size attribute ??? -- Note: Psect_Object shares this processing 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 the pragma Insert_After_And_Analyze (N, 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 => "common_object")), Make_Pragma_Argument_Association (Ploc, Expression => New_Copy_Tree (Psect))))); end Expand_Pragma_Common_Object; --------------------------------------- -- Expand_Pragma_Import_Or_Interface -- --------------------------------------- procedure Expand_Pragma_Import_Or_Interface (N : Node_Id) is Def_Id : Entity_Id; begin -- In Relaxed_RM_Semantics, support old Ada 83 style: -- pragma Import (Entity, "external name"); if Relaxed_RM_Semantics and then List_Length (Pragma_Argument_Associations (N)) = 2 and then Chars (Pragma_Identifier (N)) = Name_Import and then Nkind (Arg2 (N)) = N_String_Literal then Def_Id := Entity (Arg1 (N)); else Def_Id := Entity (Arg2 (N)); end if; -- Variable case (we have to undo any initialization already done) if Ekind (Def_Id) = E_Variable then Undo_Initialization (Def_Id, N); -- Case of exception with convention C++ elsif Ekind (Def_Id) = E_Exception and then Convention (Def_Id) = Convention_CPP then -- Import a C++ convention declare Loc : constant Source_Ptr := Sloc (N); Rtti_Name : constant Node_Id := Arg3 (N); Dum : constant Entity_Id := Make_Temporary (Loc, 'D'); Exdata : List_Id; Lang_Char : Node_Id; Foreign_Data : Node_Id; begin Exdata := Component_Associations (Expression (Parent (Def_Id))); Lang_Char := Next (First (Exdata)); -- Change the one-character language designator to 'C' Rewrite (Expression (Lang_Char), Make_Character_Literal (Loc, Chars => Name_uC, Char_Literal_Value => UI_From_Int (Character'Pos ('C')))); Analyze (Expression (Lang_Char)); -- Change the value of Foreign_Data Foreign_Data := Next (Next (Next (Next (Lang_Char)))); Insert_Actions (Def_Id, New_List ( Make_Object_Declaration (Loc, Defining_Identifier => Dum, Object_Definition => New_Occurrence_Of (Standard_Character, Loc)), Make_Pragma (Loc, Chars => Name_Import, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Name_Ada)), Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Chars (Dum))), Make_Pragma_Argument_Association (Loc, Chars => Name_External_Name, Expression => Relocate_Node (Rtti_Name)))))); Rewrite (Expression (Foreign_Data), Unchecked_Convert_To (Standard_A_Char, Make_Attribute_Reference (Loc, Prefix => Make_Identifier (Loc, Chars (Dum)), Attribute_Name => Name_Address))); Analyze (Expression (Foreign_Data)); end; -- No special expansion required for any other case else null; end if; end Expand_Pragma_Import_Or_Interface; ------------------------------------- -- Expand_Pragma_Initial_Condition -- ------------------------------------- procedure Expand_Pragma_Initial_Condition (Spec_Or_Body : Node_Id) is Loc : constant Source_Ptr := Sloc (Spec_Or_Body); Check : Node_Id; Expr : Node_Id; Init_Cond : Node_Id; List : List_Id; Pack_Id : Entity_Id; begin if Nkind (Spec_Or_Body) = N_Package_Body then Pack_Id := Corresponding_Spec (Spec_Or_Body); if Present (Handled_Statement_Sequence (Spec_Or_Body)) then List := Statements (Handled_Statement_Sequence (Spec_Or_Body)); -- The package body lacks statements, create an empty list else List := New_List; Set_Handled_Statement_Sequence (Spec_Or_Body, Make_Handled_Sequence_Of_Statements (Loc, Statements => List)); end if; elsif Nkind (Spec_Or_Body) = N_Package_Declaration then Pack_Id := Defining_Entity (Spec_Or_Body); if Present (Visible_Declarations (Specification (Spec_Or_Body))) then List := Visible_Declarations (Specification (Spec_Or_Body)); -- The package lacks visible declarations, create an empty list else List := New_List; Set_Visible_Declarations (Specification (Spec_Or_Body), List); end if; -- This routine should not be used on anything other than packages else raise Program_Error; end if; Init_Cond := Get_Pragma (Pack_Id, Pragma_Initial_Condition); -- The caller should check whether the package is subject to pragma -- Initial_Condition. pragma Assert (Present (Init_Cond)); Expr := Get_Pragma_Arg (First (Pragma_Argument_Associations (Init_Cond))); -- The assertion expression was found to be illegal, do not generate the -- runtime check as it will repeat the illegality. if Error_Posted (Init_Cond) or else Error_Posted (Expr) then return; end if; -- Generate: -- pragma Check (Initial_Condition, ); Check := Make_Pragma (Loc, Chars => Name_Check, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Name_Initial_Condition)), Make_Pragma_Argument_Association (Loc, Expression => New_Copy_Tree (Expr)))); Append_To (List, Check); Analyze (Check); end Expand_Pragma_Initial_Condition; ------------------------------------ -- 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_Loop_Variant -- -------------------------------- -- Pragma Loop_Variant is expanded in the following manner: -- Original code -- for | while ... loop -- -- pragma Loop_Variant -- (Increases => Incr_Expr, -- Decreases => Decr_Expr); -- -- end loop; -- Expanded code -- Curr_1 : ; -- Curr_2 : ; -- Old_1 : ; -- Old_2 : ; -- Flag : Boolean := False; -- for | while ... loop -- -- if Flag then -- Old_1 := Curr_1; -- Old_2 := Curr_2; -- end if; -- Curr_1 := ; -- Curr_2 := ; -- if Flag then -- if Curr_1 /= Old_1 then -- pragma Check (Loop_Variant, Curr_1 > Old_1); -- else -- pragma Check (Loop_Variant, Curr_2 < Old_2); -- end if; -- else -- Flag := True; -- end if; -- -- end loop; procedure Expand_Pragma_Loop_Variant (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Last_Var : constant Node_Id := Last (Pragma_Argument_Associations (N)); Curr_Assign : List_Id := No_List; Flag_Id : Entity_Id := Empty; If_Stmt : Node_Id := Empty; Old_Assign : List_Id := No_List; Loop_Scop : Entity_Id; Loop_Stmt : Node_Id; Variant : Node_Id; procedure Process_Variant (Variant : Node_Id; Is_Last : Boolean); -- Process a single increasing / decreasing termination variant. Flag -- Is_Last should be set when processing the last variant. --------------------- -- Process_Variant -- --------------------- procedure Process_Variant (Variant : Node_Id; Is_Last : Boolean) is function Make_Op (Loc : Source_Ptr; Curr_Val : Node_Id; Old_Val : Node_Id) return Node_Id; -- Generate a comparison between Curr_Val and Old_Val depending on -- the change mode (Increases / Decreases) of the variant. ------------- -- Make_Op -- ------------- function Make_Op (Loc : Source_Ptr; Curr_Val : Node_Id; Old_Val : Node_Id) return Node_Id is begin if Chars (Variant) = Name_Increases then return Make_Op_Gt (Loc, Curr_Val, Old_Val); else pragma Assert (Chars (Variant) = Name_Decreases); return Make_Op_Lt (Loc, Curr_Val, Old_Val); end if; end Make_Op; -- Local variables Expr : constant Node_Id := Expression (Variant); Expr_Typ : constant Entity_Id := Etype (Expr); Loc : constant Source_Ptr := Sloc (Expr); Loop_Loc : constant Source_Ptr := Sloc (Loop_Stmt); Curr_Id : Entity_Id; Old_Id : Entity_Id; Prag : Node_Id; -- Start of processing for Process_Variant begin -- All temporaries generated in this routine must be inserted before -- the related loop statement. Ensure that the proper scope is on the -- stack when analyzing the temporaries. Note that we also use the -- Sloc of the related loop. Push_Scope (Scope (Loop_Scop)); -- Step 1: Create the declaration of the flag which controls the -- behavior of the assertion on the first iteration of the loop. if No (Flag_Id) then -- Generate: -- Flag : Boolean := False; Flag_Id := Make_Temporary (Loop_Loc, 'F'); Insert_Action (Loop_Stmt, Make_Object_Declaration (Loop_Loc, Defining_Identifier => Flag_Id, Object_Definition => New_Occurrence_Of (Standard_Boolean, Loop_Loc), Expression => New_Occurrence_Of (Standard_False, Loop_Loc))); -- Prevent an unwanted optimization where the Current_Value of -- the flag eliminates the if statement which stores the variant -- values coming from the previous iteration. -- Flag : Boolean := False; -- loop -- if Flag then -- condition rewritten to False -- Old_N := Curr_N; -- and if statement eliminated -- end if; -- . . . -- Flag := True; -- end loop; Set_Current_Value (Flag_Id, Empty); end if; -- Step 2: Create the temporaries which store the old and current -- values of the associated expression. -- Generate: -- Curr : ; Curr_Id := Make_Temporary (Loc, 'C'); Insert_Action (Loop_Stmt, Make_Object_Declaration (Loop_Loc, Defining_Identifier => Curr_Id, Object_Definition => New_Occurrence_Of (Expr_Typ, Loop_Loc))); -- Generate: -- Old : ; Old_Id := Make_Temporary (Loc, 'P'); Insert_Action (Loop_Stmt, Make_Object_Declaration (Loop_Loc, Defining_Identifier => Old_Id, Object_Definition => New_Occurrence_Of (Expr_Typ, Loop_Loc))); -- Restore original scope after all temporaries have been analyzed Pop_Scope; -- Step 3: Store value of the expression from the previous iteration if No (Old_Assign) then Old_Assign := New_List; end if; -- Generate: -- Old := Curr; Append_To (Old_Assign, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Old_Id, Loc), Expression => New_Occurrence_Of (Curr_Id, Loc))); -- Step 4: Store the current value of the expression if No (Curr_Assign) then Curr_Assign := New_List; end if; -- Generate: -- Curr := ; Append_To (Curr_Assign, Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Curr_Id, Loc), Expression => Relocate_Node (Expr))); -- Step 5: Create corresponding assertion to verify change of value -- Generate: -- pragma Check (Loop_Variant, Curr <|> Old); Prag := Make_Pragma (Loc, Chars => Name_Check, Pragma_Argument_Associations => New_List ( Make_Pragma_Argument_Association (Loc, Expression => Make_Identifier (Loc, Name_Loop_Variant)), Make_Pragma_Argument_Association (Loc, Expression => Make_Op (Loc, Curr_Val => New_Occurrence_Of (Curr_Id, Loc), Old_Val => New_Occurrence_Of (Old_Id, Loc))))); -- Generate: -- if Curr /= Old then -- ; if No (If_Stmt) then -- When there is just one termination variant, do not compare the -- old and current value for equality, just check the pragma. if Is_Last then If_Stmt := Prag; else If_Stmt := Make_If_Statement (Loc, Condition => Make_Op_Ne (Loc, Left_Opnd => New_Occurrence_Of (Curr_Id, Loc), Right_Opnd => New_Occurrence_Of (Old_Id, Loc)), Then_Statements => New_List (Prag)); end if; -- Generate: -- else -- ; -- end if; elsif Is_Last then Set_Else_Statements (If_Stmt, New_List (Prag)); -- Generate: -- elsif Curr /= Old then -- ; else if Elsif_Parts (If_Stmt) = No_List then Set_Elsif_Parts (If_Stmt, New_List); end if; Append_To (Elsif_Parts (If_Stmt), Make_Elsif_Part (Loc, Condition => Make_Op_Ne (Loc, Left_Opnd => New_Occurrence_Of (Curr_Id, Loc), Right_Opnd => New_Occurrence_Of (Old_Id, Loc)), Then_Statements => New_List (Prag))); end if; end Process_Variant; -- Start of processing for Expand_Pragma_Loop_Variant begin -- If pragma is not enabled, rewrite as Null statement. If pragma is -- disabled, it has already been rewritten as a Null statement. if Is_Ignored (N) then Rewrite (N, Make_Null_Statement (Loc)); Analyze (N); return; end if; -- Locate the enclosing loop for which this assertion applies. In the -- case of Ada 2012 array iteration, we might be dealing with nested -- loops. Only the outermost loop has an identifier. Loop_Stmt := N; while Present (Loop_Stmt) loop if Nkind (Loop_Stmt) = N_Loop_Statement and then Present (Identifier (Loop_Stmt)) then exit; end if; Loop_Stmt := Parent (Loop_Stmt); end loop; Loop_Scop := Entity (Identifier (Loop_Stmt)); -- Create the circuitry which verifies individual variants Variant := First (Pragma_Argument_Associations (N)); while Present (Variant) loop Process_Variant (Variant, Is_Last => Variant = Last_Var); Next (Variant); end loop; -- Construct the segment which stores the old values of all expressions. -- Generate: -- if Flag then -- -- end if; Insert_Action (N, Make_If_Statement (Loc, Condition => New_Occurrence_Of (Flag_Id, Loc), Then_Statements => Old_Assign)); -- Update the values of all expressions Insert_Actions (N, Curr_Assign); -- Add the assertion circuitry to test all changes in expressions. -- Generate: -- if Flag then -- -- else -- Flag := True; -- end if; Insert_Action (N, Make_If_Statement (Loc, Condition => New_Occurrence_Of (Flag_Id, Loc), Then_Statements => New_List (If_Stmt), Else_Statements => New_List ( Make_Assignment_Statement (Loc, Name => New_Occurrence_Of (Flag_Id, Loc), Expression => New_Occurrence_Of (Standard_True, Loc))))); -- Note: the pragma has been completely transformed into a sequence of -- corresponding declarations and statements. We leave it in the tree -- for documentation purposes. It will be ignored by the backend. end Expand_Pragma_Loop_Variant; -------------------------------- -- Expand_Pragma_Psect_Object -- -------------------------------- -- Convert to Common_Object, and expand the resulting pragma procedure Expand_Pragma_Psect_Object (N : Node_Id) renames Expand_Pragma_Common_Object; ------------------------------------- -- Expand_Pragma_Relative_Deadline -- ------------------------------------- procedure Expand_Pragma_Relative_Deadline (N : Node_Id) is P : constant Node_Id := Parent (N); Loc : constant Source_Ptr := Sloc (N); begin -- Expand the pragma only in the case of the main subprogram. For tasks -- the expansion is done in exp_ch9. Generate a call to Set_Deadline -- at Clock plus the relative deadline specified in the pragma. Time -- values are translated into Duration to allow for non-private -- addition operation. if Nkind (P) = N_Subprogram_Body then Rewrite (N, Make_Procedure_Call_Statement (Loc, Name => New_Occurrence_Of (RTE (RE_Set_Deadline), Loc), Parameter_Associations => New_List ( Unchecked_Convert_To (RTE (RO_RT_Time), Make_Op_Add (Loc, Left_Opnd => Make_Function_Call (Loc, New_Occurrence_Of (RTE (RO_RT_To_Duration), Loc), New_List (Make_Function_Call (Loc, New_Occurrence_Of (RTE (RE_Clock), Loc)))), Right_Opnd => Unchecked_Convert_To (Standard_Duration, Arg1 (N))))))); Analyze (N); end if; end Expand_Pragma_Relative_Deadline; ------------------------------------------- -- Expand_Pragma_Suppress_Initialization -- ------------------------------------------- procedure Expand_Pragma_Suppress_Initialization (N : Node_Id) is Def_Id : constant Entity_Id := Entity (Arg1 (N)); begin -- Variable case (we have to undo any initialization already done) if Ekind (Def_Id) = E_Variable then Undo_Initialization (Def_Id, N); end if; end Expand_Pragma_Suppress_Initialization; ------------------------- -- Undo_Initialization -- ------------------------- procedure Undo_Initialization (Def_Id : Entity_Id; N : Node_Id) is Init_Call : Node_Id; begin -- 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 thus 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 (so -- this elaboration cannot be deferred to the freeze point). -- Find and remove generated initialization call for object, if any Init_Call := Remove_Init_Call (Def_Id, Rep_Clause => N); -- 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; -- The object may not have any initialization, but in the presence of -- Initialize_Scalars code is inserted after then declaration, which -- must now be removed as well. The code carries the same source -- location as the declaration itself. if Initialize_Scalars and then Is_Array_Type (Etype (Def_Id)) then declare Init : Node_Id; Nxt : Node_Id; begin Init := Next (Parent (Def_Id)); while not Comes_From_Source (Init) and then Sloc (Init) = Sloc (Def_Id) loop Nxt := Next (Init); Remove (Init); Init := Nxt; end loop; end; end if; end Undo_Initialization; end Exp_Prag;