1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 with Atree; use Atree;
27 with Casing; use Casing;
28 with Debug; use Debug;
29 with Einfo; use Einfo;
30 with Elists; use Elists;
31 with Errout; use Errout;
32 with Exp_Ch7; use Exp_Ch7;
33 with Exp_Util; use Exp_Util;
34 with Namet; use Namet;
35 with Nlists; use Nlists;
36 with Nmake; use Nmake;
38 with Restrict; use Restrict;
39 with Rident; use Rident;
40 with Rtsfind; use Rtsfind;
42 with Sem_Ch8; use Sem_Ch8;
43 with Sem_Res; use Sem_Res;
44 with Sem_Util; use Sem_Util;
45 with Sinfo; use Sinfo;
46 with Sinput; use Sinput;
47 with Snames; use Snames;
48 with Stand; use Stand;
49 with Stringt; use Stringt;
50 with Targparm; use Targparm;
51 with Tbuild; use Tbuild;
52 with Uintp; use Uintp;
54 package body Exp_Ch11 is
56 -----------------------
57 -- Local Subprograms --
58 -----------------------
60 procedure Warn_No_Exception_Propagation_Active (N : Node_Id);
61 -- Generates warning that pragma Restrictions (No_Exception_Propagation)
62 -- is in effect. Caller then generates appropriate continuation message.
63 -- N is the node on which the warning is placed.
65 procedure Warn_If_No_Propagation (N : Node_Id);
66 -- Called for an exception raise that is not a local raise (and thus can
67 -- not be optimized to a goto. Issues warning if No_Exception_Propagation
68 -- restriction is set. N is the node for the raise or equivalent call.
70 ---------------------------
71 -- Expand_At_End_Handler --
72 ---------------------------
74 -- For a handled statement sequence that has a cleanup (At_End_Proc
75 -- field set), an exception handler of the following form is required:
82 -- Note: this exception handler is treated rather specially by
83 -- subsequent expansion in two respects:
85 -- The normal call to Undefer_Abort is omitted
86 -- The raise call does not do Defer_Abort
88 -- This is because the current tasking code seems to assume that
89 -- the call to the cleanup routine that is made from an exception
90 -- handler for the abort signal is called with aborts deferred.
92 -- This expansion is only done if we have front end exception handling.
93 -- If we have back end exception handling, then the AT END handler is
94 -- left alone, and cleanups (including the exceptional case) are handled
97 -- In the front end case, the exception handler described above handles
98 -- the exceptional case. The AT END handler is left in the generated tree
99 -- and the code generator (e.g. gigi) must still handle proper generation
100 -- of cleanup calls for the non-exceptional case.
102 procedure Expand_At_End_Handler (HSS : Node_Id; Block : Node_Id) is
103 Clean : constant Entity_Id := Entity (At_End_Proc (HSS));
104 Loc : constant Source_Ptr := Sloc (Clean);
109 pragma Assert (Present (Clean));
110 pragma Assert (No (Exception_Handlers (HSS)));
112 -- Don't expand if back end exception handling active
114 if Exception_Mechanism = Back_End_Exceptions then
118 -- Don't expand an At End handler if we have already had configurable
119 -- run-time violations, since likely this will just be a matter of
120 -- generating useless cascaded messages
122 if Configurable_Run_Time_Violations > 0 then
126 -- Don't expand an At End handler if we are not allowing exceptions
127 -- or if exceptions are transformed into local gotos, and never
128 -- propagated (No_Exception_Propagation).
130 if No_Exception_Handlers_Set then
134 if Present (Block) then
139 Make_Others_Choice (Loc);
140 Set_All_Others (Ohandle);
143 Make_Procedure_Call_Statement (Loc,
144 Name => New_Occurrence_Of (Clean, Loc)));
146 -- Generate reraise statement as last statement of AT-END handler,
147 -- unless we are under control of No_Exception_Propagation, in which
148 -- case no exception propagation is possible anyway, so we do not need
149 -- a reraise (the AT END handler in this case is only for normal exits
150 -- not for exceptional exits). Also, we flag the Reraise statement as
151 -- being part of an AT END handler to prevent signalling this reraise
152 -- as a violation of the restriction when it is not set.
154 if not Restriction_Active (No_Exception_Propagation) then
156 Rstm : constant Node_Id := Make_Raise_Statement (Loc);
158 Set_From_At_End (Rstm);
159 Append_To (Stmnts, Rstm);
163 Set_Exception_Handlers (HSS, New_List (
164 Make_Implicit_Exception_Handler (Loc,
165 Exception_Choices => New_List (Ohandle),
166 Statements => Stmnts)));
168 Analyze_List (Stmnts, Suppress => All_Checks);
169 Expand_Exception_Handlers (HSS);
171 if Present (Block) then
174 end Expand_At_End_Handler;
176 -------------------------------
177 -- Expand_Exception_Handlers --
178 -------------------------------
180 procedure Expand_Exception_Handlers (HSS : Node_Id) is
181 Handlrs : constant List_Id := Exception_Handlers (HSS);
182 Loc : constant Source_Ptr := Sloc (HSS);
184 Others_Choice : Boolean;
186 Next_Handler : Node_Id;
188 procedure Expand_Local_Exception_Handlers;
189 -- This procedure handles the expansion of exception handlers for the
190 -- optimization of local raise statements into goto statements.
192 procedure Prepend_Call_To_Handler
194 Args : List_Id := No_List);
195 -- Routine to prepend a call to the procedure referenced by Proc at
196 -- the start of the handler code for the current Handler.
198 procedure Replace_Raise_By_Goto (Raise_S : Node_Id; Goto_L1 : Node_Id);
199 -- Raise_S is a raise statement (possibly expanded, and possibly of the
200 -- form of a Raise_xxx_Error node with a condition. This procedure is
201 -- called to replace the raise action with the (already analyzed) goto
202 -- statement passed as Goto_L1. This procedure also takes care of the
203 -- requirement of inserting a Local_Raise call where possible.
205 -------------------------------------
206 -- Expand_Local_Exception_Handlers --
207 -------------------------------------
209 -- There are two cases for this transformation. First the case of
210 -- explicit raise statements. For this case, the transformation we do
211 -- looks like this. Right now we have for example (where L1, L2 are
216 -- raise_exception (excep1'identity); -- was raise excep1
218 -- raise_exception (excep2'identity); -- was raise excep2
227 -- This gets transformed into:
230 -- L1 : label; -- marked Exception_Junk
231 -- L2 : label; -- marked Exception_Junk
232 -- L3 : label; -- marked Exception_Junk
234 -- begin -- marked Exception_Junk
236 -- local_raise (excep1'address); -- was raise excep1
239 -- local_raise (excep2'address); -- was raise excep2
249 -- goto L3; -- skip handler if no raise, marked Exception_Junk
251 -- <<L1>> -- local excep target label, marked Exception_Junk
252 -- begin -- marked Exception_Junk
255 -- goto L3; -- marked Exception_Junk
257 -- <<L2>> -- marked Exception_Junk
258 -- begin -- marked Exception_Junk
261 -- goto L3; -- marked Exception_Junk
262 -- <<L3>> -- marked Exception_Junk
265 -- Note: the reason we wrap the original statement sequence in an
266 -- inner block is that there may be raise statements within the
267 -- sequence of statements in the handlers, and we must ensure that
268 -- these are properly handled, and in particular, such raise statements
269 -- must not reenter the same exception handlers.
271 -- If the restriction No_Exception_Propagation is in effect, then we
272 -- can omit the exception handlers.
275 -- L1 : label; -- marked Exception_Junk
276 -- L2 : label; -- marked Exception_Junk
277 -- L3 : label; -- marked Exception_Junk
279 -- begin -- marked Exception_Junk
281 -- local_raise (excep1'address); -- was raise excep1
284 -- local_raise (excep2'address); -- was raise excep2
289 -- goto L3; -- skip handler if no raise, marked Exception_Junk
291 -- <<L1>> -- local excep target label, marked Exception_Junk
292 -- begin -- marked Exception_Junk
295 -- goto L3; -- marked Exception_Junk
297 -- <<L2>> -- marked Exception_Junk
298 -- begin -- marked Exception_Junk
302 -- <<L3>> -- marked Exception_Junk
305 -- The second case is for exceptions generated by the back end in one
306 -- of three situations:
308 -- 1. Front end generates N_Raise_xxx_Error node
309 -- 2. Front end sets Do_xxx_Check flag in subexpression node
310 -- 3. Back end detects a situation where an exception is appropriate
312 -- In all these cases, the current processing in gigi is to generate a
313 -- call to the appropriate Rcheck_xx routine (where xx encodes both the
314 -- exception message and the exception to be raised, Constraint_Error,
315 -- Program_Error, or Storage_Error.
317 -- We could handle some subcases of 1 using the same front end expansion
318 -- into gotos, but even for case 1, we can't handle all cases, since
319 -- generating gotos in the middle of expressions is not possible (it's
320 -- possible at the gigi/gcc level, but not at the level of the GNAT
323 -- In any case, it seems easier to have a scheme which handles all three
324 -- cases in a uniform manner. So here is how we proceed in this case.
326 -- This procedure detects all handlers for these three exceptions,
327 -- Constraint_Error, Program_Error and Storage_Error (including WHEN
328 -- OTHERS handlers that cover one or more of these cases).
330 -- If the handler meets the requirements for being the target of a local
331 -- raise, then the front end does the expansion described previously,
332 -- creating a label to be used as a goto target to raise the exception.
333 -- However, no attempt is made in the front end to convert any related
334 -- raise statements into gotos, e.g. all N_Raise_xxx_Error nodes are
335 -- left unchanged and passed to the back end.
337 -- Instead, the front end generates two nodes
339 -- N_Push_Constraint_Error_Label
340 -- N_Push_Program_Error_Label
341 -- N_Push_Storage_Error_Label
343 -- The Push node is generated at the start of the statements
344 -- covered by the handler, and has as a parameter the label to be
345 -- used as the raise target.
347 -- N_Pop_Constraint_Error_Label
348 -- N_Pop_Program_Error_Label
349 -- N_Pop_Storage_Error_Label
351 -- The Pop node is generated at the end of the covered statements
352 -- and undoes the effect of the preceding corresponding Push node.
354 -- In the case where the handler does NOT meet the requirements, the
355 -- front end will still generate the Push and Pop nodes, but the label
356 -- field in the Push node will be empty signifying that for this region
357 -- of code, no optimization is possible.
359 -- The back end must maintain three stacks, one for each exception case,
360 -- the Push node pushes an entry onto the corresponding stack, and Pop
361 -- node pops off the entry. Then instead of calling Rcheck_nn, if the
362 -- corresponding top stack entry has an non-empty label, a goto is
363 -- generated. This goto should be preceded by a call to Local_Raise as
366 -- An example of this transformation is as follows, given:
369 -- A : Integer range 1 .. 10;
373 -- when Constraint_Error =>
377 -- gets transformed to:
380 -- A : Integer range 1 .. 10;
387 -- %push_constraint_error_label (L1)
388 -- R1b : constant long_long_integer := long_long_integer?(b) +
389 -- long_long_integer?(c);
390 -- [constraint_error when
391 -- not (R1b in -16#8000_0000# .. 16#7FFF_FFFF#)
392 -- "overflow check failed"]
393 -- a := integer?(R1b);
394 -- %pop_constraint_error_Label
398 -- when constraint_error =>
402 -- goto L2; -- skip handler when exception not raised
403 -- <<L1>> -- target label for local exception
408 -- Note: the generated labels and goto statements all have the flag
409 -- Exception_Junk set True, so that Sem_Ch6.Check_Returns will ignore
410 -- this generated exception stuff when checking for missing return
411 -- statements (see circuitry in Check_Statement_Sequence).
413 -- Note: All of the processing described above occurs only if
414 -- restriction No_Exception_Propagation applies or debug flag .g is
417 CE_Locally_Handled : Boolean := False;
418 SE_Locally_Handled : Boolean := False;
419 PE_Locally_Handled : Boolean := False;
420 -- These three flags indicate whether a handler for the corresponding
421 -- exception (CE=Constraint_Error, SE=Storage_Error, PE=Program_Error)
422 -- is present. If so the switch is set to True, the Exception_Label
423 -- field of the corresponding handler is set, and appropriate Push
424 -- and Pop nodes are inserted into the code.
426 Local_Expansion_Required : Boolean := False;
427 -- Set True if we have at least one handler requiring local raise
428 -- expansion as described above.
430 procedure Expand_Local_Exception_Handlers is
432 procedure Add_Exception_Label (H : Node_Id);
433 -- H is an exception handler. First check for an Exception_Label
434 -- already allocated for H. If none, allocate one, set the field in
435 -- the handler node, add the label declaration, and set the flag
436 -- Local_Expansion_Required. Note: if Local_Raise_Not_OK is set
437 -- the call has no effect and Exception_Label is left empty.
439 procedure Add_Label_Declaration (L : Entity_Id);
440 -- Add an implicit declaration of the given label to the declaration
441 -- list in the parent of the current sequence of handled statements.
444 Exc_Locally_Handled : in out Boolean;
445 -- Flag indicating whether a local handler for this exception
446 -- has already been generated.
448 with function Make_Push_Label (Loc : Source_Ptr) return Node_Id;
449 -- Function to create a Push_xxx_Label node
451 with function Make_Pop_Label (Loc : Source_Ptr) return Node_Id;
452 -- Function to create a Pop_xxx_Label node
454 procedure Generate_Push_Pop (H : Node_Id);
455 -- Common code for Generate_Push_Pop_xxx below, used to generate an
456 -- exception label and Push/Pop nodes for Constraint_Error,
457 -- Program_Error, or Storage_Error.
459 -------------------------
460 -- Add_Exception_Label --
461 -------------------------
463 procedure Add_Exception_Label (H : Node_Id) is
465 if No (Exception_Label (H))
466 and then not Local_Raise_Not_OK (H)
467 and then not Special_Exception_Package_Used
469 Local_Expansion_Required := True;
472 L : constant Entity_Id :=
473 Make_Defining_Identifier (Sloc (H),
474 Chars => New_Internal_Name ('L'));
476 Set_Exception_Label (H, L);
477 Add_Label_Declaration (L);
480 end Add_Exception_Label;
482 ---------------------------
483 -- Add_Label_Declaration --
484 ---------------------------
486 procedure Add_Label_Declaration (L : Entity_Id) is
487 P : constant Node_Id := Parent (HSS);
489 Decl_L : constant Node_Id :=
490 Make_Implicit_Label_Declaration (Loc,
491 Defining_Identifier => L);
494 if Declarations (P) = No_List then
495 Set_Declarations (P, Empty_List);
498 Append (Decl_L, Declarations (P));
500 end Add_Label_Declaration;
502 -----------------------
503 -- Generate_Push_Pop --
504 -----------------------
506 procedure Generate_Push_Pop (H : Node_Id) is
508 if Exc_Locally_Handled then
511 Exc_Locally_Handled := True;
514 Add_Exception_Label (H);
517 F : constant Node_Id := First (Statements (HSS));
518 L : constant Node_Id := Last (Statements (HSS));
520 Push : constant Node_Id := Make_Push_Label (Sloc (F));
521 Pop : constant Node_Id := Make_Pop_Label (Sloc (L));
524 -- We make sure that a call to Get_Local_Raise_Call_Entity is
525 -- made during front end processing, so that when we need it
526 -- in the back end, it will already be available and loaded.
528 Discard_Node (Get_Local_Raise_Call_Entity);
530 -- Prepare and insert Push and Pop nodes
532 Set_Exception_Label (Push, Exception_Label (H));
533 Insert_Before (F, Push);
536 Insert_After (L, Pop);
539 end Generate_Push_Pop;
541 -- Local declarations
543 Loc : constant Source_Ptr := Sloc (HSS);
544 Stmts : List_Id := No_List;
548 procedure Generate_Push_Pop_For_Constraint_Error is
549 new Generate_Push_Pop
550 (Exc_Locally_Handled => CE_Locally_Handled,
551 Make_Push_Label => Make_Push_Constraint_Error_Label,
552 Make_Pop_Label => Make_Pop_Constraint_Error_Label);
553 -- If no Push/Pop has been generated for CE yet, then set the flag
554 -- CE_Locally_Handled, allocate an Exception_Label for handler H (if
555 -- not already done), and generate Push/Pop nodes for the exception
556 -- label at the start and end of the statements of HSS.
558 procedure Generate_Push_Pop_For_Program_Error is
559 new Generate_Push_Pop
560 (Exc_Locally_Handled => PE_Locally_Handled,
561 Make_Push_Label => Make_Push_Program_Error_Label,
562 Make_Pop_Label => Make_Pop_Program_Error_Label);
563 -- If no Push/Pop has been generated for PE yet, then set the flag
564 -- PE_Locally_Handled, allocate an Exception_Label for handler H (if
565 -- not already done), and generate Push/Pop nodes for the exception
566 -- label at the start and end of the statements of HSS.
568 procedure Generate_Push_Pop_For_Storage_Error is
569 new Generate_Push_Pop
570 (Exc_Locally_Handled => SE_Locally_Handled,
571 Make_Push_Label => Make_Push_Storage_Error_Label,
572 Make_Pop_Label => Make_Pop_Storage_Error_Label);
573 -- If no Push/Pop has been generated for SE yet, then set the flag
574 -- SE_Locally_Handled, allocate an Exception_Label for handler H (if
575 -- not already done), and generate Push/Pop nodes for the exception
576 -- label at the start and end of the statements of HSS.
578 -- Start of processing for Expand_Local_Exception_Handlers
581 -- No processing if all exception handlers will get removed
583 if Debug_Flag_Dot_X then
587 -- See for each handler if we have any local raises to expand
589 Handler := First_Non_Pragma (Handlrs);
590 while Present (Handler) loop
592 -- Note, we do not test Local_Raise_Not_OK here, because in the
593 -- case of Push/Pop generation we want to generate push with a
594 -- null label. The Add_Exception_Label routine has no effect if
595 -- Local_Raise_Not_OK is set, so this works as required.
597 if Present (Local_Raise_Statements (Handler)) then
598 Add_Exception_Label (Handler);
601 -- If we are doing local raise to goto optimization (restriction
602 -- No_Exception_Propagation set or debug flag .g set), then check
603 -- to see if handler handles CE, PE, SE and if so generate the
604 -- appropriate push/pop sequence for the back end.
607 or else Restriction_Active (No_Exception_Propagation))
608 and then Has_Local_Raise (Handler)
610 Choice := First (Exception_Choices (Handler));
611 while Present (Choice) loop
612 if Nkind (Choice) = N_Others_Choice
613 and then not All_Others (Choice)
615 Generate_Push_Pop_For_Constraint_Error (Handler);
616 Generate_Push_Pop_For_Program_Error (Handler);
617 Generate_Push_Pop_For_Storage_Error (Handler);
619 elsif Is_Entity_Name (Choice) then
620 Excep := Get_Renamed_Entity (Entity (Choice));
622 if Excep = Standard_Constraint_Error then
623 Generate_Push_Pop_For_Constraint_Error (Handler);
624 elsif Excep = Standard_Program_Error then
625 Generate_Push_Pop_For_Program_Error (Handler);
626 elsif Excep = Standard_Storage_Error then
627 Generate_Push_Pop_For_Storage_Error (Handler);
635 Next_Non_Pragma (Handler);
638 -- Nothing to do if no handlers requiring the goto transformation
640 if not (Local_Expansion_Required) then
644 -- Prepare to do the transformation
647 -- L3 is the label to exit the HSS
649 L3_Dent : constant Entity_Id :=
650 Make_Defining_Identifier (Loc,
651 Chars => New_Internal_Name ('L'));
653 Labl_L3 : constant Node_Id :=
655 Identifier => New_Occurrence_Of (L3_Dent, Loc));
661 Set_Exception_Junk (Labl_L3);
662 Add_Label_Declaration (L3_Dent);
664 -- Wrap existing statements and handlers in an inner block
667 Make_Block_Statement (Loc,
668 Handled_Statement_Sequence => Relocate_Node (HSS));
669 Set_Exception_Junk (Blk_Stm);
672 Make_Handled_Sequence_Of_Statements (Loc,
673 Statements => New_List (Blk_Stm)));
675 -- Set block statement as analyzed, we don't want to actually call
676 -- Analyze on this block, it would cause a recursion in exception
677 -- handler processing which would mess things up.
679 Set_Analyzed (Blk_Stm);
681 -- Now loop through the exception handlers to deal with those that
682 -- are targets of local raise statements.
684 Handler := First_Non_Pragma (Handlrs);
685 while Present (Handler) loop
686 if Present (Exception_Label (Handler)) then
688 -- This handler needs the goto expansion
691 Loc : constant Source_Ptr := Sloc (Handler);
693 -- L1 is the start label for this handler
695 L1_Dent : constant Entity_Id := Exception_Label (Handler);
697 Labl_L1 : constant Node_Id :=
700 New_Occurrence_Of (L1_Dent, Loc));
702 -- Jump to L1 to be used as replacement for the original
703 -- handler (used in the case where exception propagation
706 Name_L1 : constant Node_Id :=
707 New_Occurrence_Of (L1_Dent, Loc);
709 Goto_L1 : constant Node_Id :=
710 Make_Goto_Statement (Loc,
713 -- Jump to L3 to be used at the end of handler
715 Name_L3 : constant Node_Id :=
716 New_Occurrence_Of (L3_Dent, Loc);
718 Goto_L3 : constant Node_Id :=
719 Make_Goto_Statement (Loc,
722 H_Stmts : constant List_Id := Statements (Handler);
725 Set_Exception_Junk (Labl_L1);
726 Set_Exception_Junk (Goto_L3);
728 -- Note: we do NOT set Exception_Junk in Goto_L1, since
729 -- this is a real transfer of control that we want the
730 -- Sem_Ch6.Check_Returns procedure to recognize properly.
732 -- Replace handler by a goto L1. We can mark this as
733 -- analyzed since it is fully formed, and we don't
734 -- want it going through any further checks. We save
735 -- the last statement location in the goto L1 node for
736 -- the benefit of Sem_Ch6.Check_Returns.
738 Set_Statements (Handler, New_List (Goto_L1));
739 Set_Analyzed (Goto_L1);
740 Set_Etype (Name_L1, Standard_Void_Type);
742 -- Now replace all the raise statements by goto L1
744 if Present (Local_Raise_Statements (Handler)) then
745 Relmt := First_Elmt (Local_Raise_Statements (Handler));
746 while Present (Relmt) loop
748 Raise_S : constant Node_Id := Node (Relmt);
750 Name_L1 : constant Node_Id :=
751 New_Occurrence_Of (L1_Dent, Loc);
753 Goto_L1 : constant Node_Id :=
754 Make_Goto_Statement (Loc,
758 -- Replace raise by goto L1
760 Set_Analyzed (Goto_L1);
761 Set_Etype (Name_L1, Standard_Void_Type);
762 Replace_Raise_By_Goto (Raise_S, Goto_L1);
769 -- Add a goto L3 at end of statement list in block. The
770 -- first time, this is what skips over the exception
771 -- handlers in the normal case. Subsequent times, it
772 -- terminates the execution of the previous handler code,
773 -- and skips subsequent handlers.
775 Stmts := Statements (HSS);
777 Insert_After (Last (Stmts), Goto_L3);
778 Set_Analyzed (Goto_L3);
779 Set_Etype (Name_L3, Standard_Void_Type);
781 -- Now we drop the label that marks the handler start,
782 -- followed by the statements of the handler.
784 Set_Etype (Identifier (Labl_L1), Standard_Void_Type);
786 Insert_After_And_Analyze (Last (Stmts), Labl_L1);
789 Loc : constant Source_Ptr := Sloc (First (H_Stmts));
790 Blk : constant Node_Id :=
791 Make_Block_Statement (Loc,
792 Handled_Statement_Sequence =>
793 Make_Handled_Sequence_Of_Statements (Loc,
794 Statements => H_Stmts));
796 Set_Exception_Junk (Blk);
797 Insert_After_And_Analyze (Last (Stmts), Blk);
801 -- Here if we have local raise statements but the handler is
802 -- not suitable for processing with a local raise. In this
803 -- case we have to generate possible diagnostics.
805 elsif Has_Local_Raise (Handler)
806 and then Local_Raise_Statements (Handler) /= No_Elist
808 Relmt := First_Elmt (Local_Raise_Statements (Handler));
809 while Present (Relmt) loop
810 Warn_If_No_Propagation (Node (Relmt));
818 -- Only remaining step is to drop the L3 label and we are done
820 Set_Etype (Identifier (Labl_L3), Standard_Void_Type);
822 -- If we had at least one handler, then we drop the label after
823 -- the last statement of that handler.
825 if Stmts /= No_List then
826 Insert_After_And_Analyze (Last (Stmts), Labl_L3);
828 -- Otherwise we have removed all the handlers (this results from
829 -- use of pragma Restrictions (No_Exception_Propagation), and we
830 -- drop the label at the end of the statements of the HSS.
833 Insert_After_And_Analyze (Last (Statements (HSS)), Labl_L3);
838 end Expand_Local_Exception_Handlers;
840 -----------------------------
841 -- Prepend_Call_To_Handler --
842 -----------------------------
844 procedure Prepend_Call_To_Handler
846 Args : List_Id := No_List)
848 Ent : constant Entity_Id := RTE (Proc);
851 -- If we have no Entity, then we are probably in no run time mode or
852 -- some weird error has occurred. In either case do nothing. Note use
853 -- of No_Location to hide this code from the debugger, so single
854 -- stepping doesn't jump back and forth.
856 if Present (Ent) then
858 Call : constant Node_Id :=
859 Make_Procedure_Call_Statement (No_Location,
860 Name => New_Occurrence_Of (RTE (Proc), No_Location),
861 Parameter_Associations => Args);
864 Prepend_To (Statements (Handler), Call);
865 Analyze (Call, Suppress => All_Checks);
868 end Prepend_Call_To_Handler;
870 ---------------------------
871 -- Replace_Raise_By_Goto --
872 ---------------------------
874 procedure Replace_Raise_By_Goto (Raise_S : Node_Id; Goto_L1 : Node_Id) is
875 Loc : constant Source_Ptr := Sloc (Raise_S);
882 -- If we have a null statement, it means that there is no replacement
883 -- needed (typically this results from a suppressed check).
885 if Nkind (Raise_S) = N_Null_Statement then
888 -- Test for Raise_xxx_Error
890 elsif Nkind (Raise_S) = N_Raise_Constraint_Error then
891 Excep := Standard_Constraint_Error;
892 Cond := Condition (Raise_S);
894 elsif Nkind (Raise_S) = N_Raise_Storage_Error then
895 Excep := Standard_Storage_Error;
896 Cond := Condition (Raise_S);
898 elsif Nkind (Raise_S) = N_Raise_Program_Error then
899 Excep := Standard_Program_Error;
900 Cond := Condition (Raise_S);
902 -- The only other possibility is a node that is or used to be a
903 -- simple raise statement.
906 Orig := Original_Node (Raise_S);
907 pragma Assert (Nkind (Orig) = N_Raise_Statement
908 and then Present (Name (Orig))
909 and then No (Expression (Orig)));
910 Excep := Entity (Name (Orig));
914 -- Here Excep is the exception to raise, and Cond is the condition
915 -- First prepare the call to Local_Raise (excep'address).
917 if RTE_Available (RE_Local_Raise) then
919 Make_Procedure_Call_Statement (Loc,
920 Name => New_Occurrence_Of (RTE (RE_Local_Raise), Loc),
921 Parameter_Associations => New_List (
922 Unchecked_Convert_To (RTE (RE_Address),
923 Make_Attribute_Reference (Loc,
924 Prefix => New_Occurrence_Of (Excep, Loc),
925 Attribute_Name => Name_Identity))));
927 -- Use null statement if Local_Raise not available
931 Make_Null_Statement (Loc);
934 -- If there is no condition, we rewrite as
937 -- Local_Raise (excep'Identity);
943 Make_Block_Statement (Loc,
944 Handled_Statement_Sequence =>
945 Make_Handled_Sequence_Of_Statements (Loc,
946 Statements => New_List (LR, Goto_L1))));
947 Set_Exception_Junk (Raise_S);
949 -- If there is a condition, we rewrite as
952 -- Local_Raise (excep'Identity);
958 Make_If_Statement (Loc,
960 Then_Statements => New_List (LR, Goto_L1)));
964 end Replace_Raise_By_Goto;
966 -- Start of processing for Expand_Exception_Handlers
969 Expand_Local_Exception_Handlers;
971 -- Loop through handlers
973 Handler := First_Non_Pragma (Handlrs);
974 Handler_Loop : while Present (Handler) loop
975 Next_Handler := Next_Non_Pragma (Handler);
977 -- Remove source handler if gnat debug flag .x is set
979 if Debug_Flag_Dot_X and then Comes_From_Source (Handler) then
982 -- Remove handler if no exception propagation, generating a warning
983 -- if a source generated handler was not the target of a local raise.
986 if Restriction_Active (No_Exception_Propagation)
987 and then not Has_Local_Raise (Handler)
988 and then Comes_From_Source (Handler)
989 and then Warn_On_Non_Local_Exception
991 Warn_No_Exception_Propagation_Active (Handler);
993 ("\?this handler can never be entered, and has been removed",
997 if No_Exception_Propagation_Active then
1000 -- Exception handler is active and retained and must be processed
1003 -- If an exception occurrence is present, then we must declare
1004 -- it and initialize it from the value stored in the TSD
1007 -- name : Exception_Occurrence;
1009 -- Save_Occurrence (name, Get_Current_Excep.all)
1013 if Present (Choice_Parameter (Handler)) then
1015 Cparm : constant Entity_Id := Choice_Parameter (Handler);
1016 Cloc : constant Source_Ptr := Sloc (Cparm);
1017 Hloc : constant Source_Ptr := Sloc (Handler);
1021 -- Note use of No_Location to hide this code from the
1022 -- debugger, so single stepping doesn't jump back and
1026 Make_Procedure_Call_Statement (No_Location,
1028 New_Occurrence_Of (RTE (RE_Save_Occurrence),
1030 Parameter_Associations => New_List (
1031 New_Occurrence_Of (Cparm, Cloc),
1032 Make_Explicit_Dereference (No_Location,
1033 Make_Function_Call (No_Location,
1034 Name => Make_Explicit_Dereference (No_Location,
1036 (RTE (RE_Get_Current_Excep),
1039 Mark_Rewrite_Insertion (Save);
1040 Prepend (Save, Statements (Handler));
1043 Make_Object_Declaration
1045 Defining_Identifier => Cparm,
1046 Object_Definition =>
1048 (RTE (RE_Exception_Occurrence), Cloc));
1049 Set_No_Initialization (Obj_Decl, True);
1052 Make_Exception_Handler (Hloc,
1053 Choice_Parameter => Empty,
1054 Exception_Choices => Exception_Choices (Handler),
1056 Statements => New_List (
1057 Make_Block_Statement (Hloc,
1058 Declarations => New_List (Obj_Decl),
1059 Handled_Statement_Sequence =>
1060 Make_Handled_Sequence_Of_Statements (Hloc,
1061 Statements => Statements (Handler))))));
1063 -- Local raise statements can't occur, since exception
1064 -- handlers with choice parameters are not allowed when
1065 -- No_Exception_Propagation applies, so set attributes
1068 Set_Local_Raise_Statements (Handler, No_Elist);
1069 Set_Local_Raise_Not_OK (Handler);
1072 (Statements (Handler), Suppress => All_Checks);
1076 -- The processing at this point is rather different for the JVM
1077 -- case, so we completely separate the processing.
1079 -- For the VM case, we unconditionally call Update_Exception,
1080 -- passing a call to the intrinsic Current_Target_Exception
1081 -- (see JVM/.NET versions of Ada.Exceptions for details).
1083 if VM_Target /= No_VM then
1085 Arg : constant Node_Id :=
1086 Make_Function_Call (Loc,
1089 (RTE (RE_Current_Target_Exception), Loc));
1091 Prepend_Call_To_Handler
1092 (RE_Update_Exception, New_List (Arg));
1095 -- For the normal case, we have to worry about the state of
1096 -- abort deferral. Generally, we defer abort during runtime
1097 -- handling of exceptions. When control is passed to the
1098 -- handler, then in the normal case we undefer aborts. In
1099 -- any case this entire handling is relevant only if aborts
1102 elsif Abort_Allowed then
1104 -- There are some special cases in which we do not do the
1105 -- undefer. In particular a finalization (AT END) handler
1106 -- wants to operate with aborts still deferred.
1108 -- We also suppress the call if this is the special handler
1109 -- for Abort_Signal, since if we are aborting, we want to
1110 -- keep aborts deferred (one abort is enough).
1112 -- If abort really needs to be deferred the expander must
1113 -- add this call explicitly, see
1114 -- Expand_N_Asynchronous_Select.
1117 Nkind (First (Exception_Choices (Handler))) =
1121 or else Entity (First (Exception_Choices (Handler))) /=
1126 All_Others (First (Exception_Choices (Handler))))
1127 and then Abort_Allowed
1129 Prepend_Call_To_Handler (RE_Abort_Undefer);
1135 Handler := Next_Handler;
1136 end loop Handler_Loop;
1138 -- If all handlers got removed, then remove the list. Note we cannot
1139 -- reference HSS here, since expanding local handlers may have buried
1140 -- the handlers in an inner block.
1142 if Is_Empty_List (Handlrs) then
1143 Set_Exception_Handlers (Parent (Handlrs), No_List);
1145 end Expand_Exception_Handlers;
1147 ------------------------------------
1148 -- Expand_N_Exception_Declaration --
1149 ------------------------------------
1152 -- exceptE : constant String := "A.B.EXCEP"; -- static data
1153 -- except : exception_data := (
1154 -- Handled_By_Other => False,
1156 -- Name_Length => exceptE'Length,
1157 -- Full_Name => exceptE'Address,
1158 -- HTable_Ptr => null,
1159 -- Import_Code => 0,
1160 -- Raise_Hook => null,
1163 -- (protecting test only needed if not at library level)
1165 -- exceptF : Boolean := True -- static data
1167 -- exceptF := False;
1168 -- Register_Exception (except'Unchecked_Access);
1171 procedure Expand_N_Exception_Declaration (N : Node_Id) is
1172 Loc : constant Source_Ptr := Sloc (N);
1173 Id : constant Entity_Id := Defining_Identifier (N);
1174 L : List_Id := New_List;
1175 Flag_Id : Entity_Id;
1177 Name_Exname : constant Name_Id := New_External_Name (Chars (Id), 'E');
1178 Exname : constant Node_Id :=
1179 Make_Defining_Identifier (Loc, Name_Exname);
1181 procedure Force_Static_Allocation_Of_Referenced_Objects
1182 (Aggregate : Node_Id);
1183 -- A specialized solution to one particular case of an ugly problem
1185 -- The given aggregate includes an Unchecked_Conversion as one of the
1186 -- component values. The call to Analyze_And_Resolve below ends up
1187 -- calling Exp_Ch4.Expand_N_Unchecked_Type_Conversion, which may decide
1188 -- to introduce a (constant) temporary and then obtain the component
1189 -- value by evaluating the temporary.
1191 -- In the case of an exception declared within a subprogram (or any
1192 -- other dynamic scope), this is a bad transformation. The exception
1193 -- object is marked as being Statically_Allocated but the temporary is
1194 -- not. If the initial value of a Statically_Allocated declaration
1195 -- references a dynamically allocated object, this prevents static
1196 -- initialization of the object.
1198 -- We cope with this here by marking the temporary Statically_Allocated.
1199 -- It might seem cleaner to generalize this utility and then use it to
1200 -- enforce a rule that the entities referenced in the declaration of any
1201 -- "hoisted" (i.e., Is_Statically_Allocated and not Is_Library_Level)
1202 -- entity must also be either Library_Level or hoisted. It turns out
1203 -- that this would be incompatible with the current treatment of an
1204 -- object which is local to a subprogram, subject to an Export pragma,
1205 -- not subject to an address clause, and whose declaration contains
1206 -- references to other local (non-hoisted) objects (e.g., in the initial
1207 -- value expression).
1209 ---------------------------------------------------
1210 -- Force_Static_Allocation_Of_Referenced_Objects --
1211 ---------------------------------------------------
1213 procedure Force_Static_Allocation_Of_Referenced_Objects
1214 (Aggregate : Node_Id)
1216 function Fixup_Node (N : Node_Id) return Traverse_Result;
1217 -- If the given node references a dynamically allocated object, then
1218 -- correct the declaration of the object.
1224 function Fixup_Node (N : Node_Id) return Traverse_Result is
1226 if Nkind (N) in N_Has_Entity
1227 and then Present (Entity (N))
1228 and then not Is_Library_Level_Entity (Entity (N))
1230 -- Note: the following test is not needed but it seems cleaner
1231 -- to do this test (this would be more important if procedure
1232 -- Force_Static_Allocation_Of_Referenced_Objects recursively
1233 -- traversed the declaration of an entity after marking it as
1234 -- statically allocated).
1236 and then not Is_Statically_Allocated (Entity (N))
1238 Set_Is_Statically_Allocated (Entity (N));
1244 procedure Fixup_Tree is new Traverse_Proc (Fixup_Node);
1246 -- Start of processing for Force_Static_Allocation_Of_Referenced_Objects
1249 Fixup_Tree (Aggregate);
1250 end Force_Static_Allocation_Of_Referenced_Objects;
1252 -- Start of processing for Expand_N_Exception_Declaration
1255 -- There is no expansion needed when compiling for the JVM since the
1256 -- JVM has a built-in exception mechanism. See 4jexcept.ads for details.
1258 if VM_Target /= No_VM then
1262 -- Definition of the external name: nam : constant String := "A.B.NAME";
1265 Make_Object_Declaration (Loc,
1266 Defining_Identifier => Exname,
1267 Constant_Present => True,
1268 Object_Definition => New_Occurrence_Of (Standard_String, Loc),
1270 Make_String_Literal (Loc,
1271 Strval => Full_Qualified_Name (Id))));
1273 Set_Is_Statically_Allocated (Exname);
1275 -- Create the aggregate list for type Standard.Exception_Type:
1276 -- Handled_By_Other component: False
1278 Append_To (L, New_Occurrence_Of (Standard_False, Loc));
1280 -- Lang component: 'A'
1283 Make_Character_Literal (Loc,
1285 Char_Literal_Value => UI_From_Int (Character'Pos ('A'))));
1287 -- Name_Length component: Nam'Length
1290 Make_Attribute_Reference (Loc,
1291 Prefix => New_Occurrence_Of (Exname, Loc),
1292 Attribute_Name => Name_Length));
1294 -- Full_Name component: Standard.A_Char!(Nam'Address)
1296 Append_To (L, Unchecked_Convert_To (Standard_A_Char,
1297 Make_Attribute_Reference (Loc,
1298 Prefix => New_Occurrence_Of (Exname, Loc),
1299 Attribute_Name => Name_Address)));
1301 -- HTable_Ptr component: null
1303 Append_To (L, Make_Null (Loc));
1305 -- Import_Code component: 0
1307 Append_To (L, Make_Integer_Literal (Loc, 0));
1309 -- Raise_Hook component: null
1311 Append_To (L, Make_Null (Loc));
1313 Set_Expression (N, Make_Aggregate (Loc, Expressions => L));
1314 Analyze_And_Resolve (Expression (N), Etype (Id));
1316 Force_Static_Allocation_Of_Referenced_Objects (Expression (N));
1318 -- Register_Exception (except'Unchecked_Access);
1320 if not No_Exception_Handlers_Set
1321 and then not Restriction_Active (No_Exception_Registration)
1324 Make_Procedure_Call_Statement (Loc,
1325 Name => New_Occurrence_Of (RTE (RE_Register_Exception), Loc),
1326 Parameter_Associations => New_List (
1327 Unchecked_Convert_To (RTE (RE_Exception_Data_Ptr),
1328 Make_Attribute_Reference (Loc,
1329 Prefix => New_Occurrence_Of (Id, Loc),
1330 Attribute_Name => Name_Unrestricted_Access)))));
1332 Set_Register_Exception_Call (Id, First (L));
1334 if not Is_Library_Level_Entity (Id) then
1335 Flag_Id := Make_Defining_Identifier (Loc,
1336 New_External_Name (Chars (Id), 'F'));
1339 Make_Object_Declaration (Loc,
1340 Defining_Identifier => Flag_Id,
1341 Object_Definition =>
1342 New_Occurrence_Of (Standard_Boolean, Loc),
1344 New_Occurrence_Of (Standard_True, Loc)));
1346 Set_Is_Statically_Allocated (Flag_Id);
1349 Make_Assignment_Statement (Loc,
1350 Name => New_Occurrence_Of (Flag_Id, Loc),
1351 Expression => New_Occurrence_Of (Standard_False, Loc)));
1353 Insert_After_And_Analyze (N,
1354 Make_Implicit_If_Statement (N,
1355 Condition => New_Occurrence_Of (Flag_Id, Loc),
1356 Then_Statements => L));
1359 Insert_List_After_And_Analyze (N, L);
1362 end Expand_N_Exception_Declaration;
1364 ---------------------------------------------
1365 -- Expand_N_Handled_Sequence_Of_Statements --
1366 ---------------------------------------------
1368 procedure Expand_N_Handled_Sequence_Of_Statements (N : Node_Id) is
1370 -- Expand exception handlers
1372 if Present (Exception_Handlers (N))
1373 and then not Restriction_Active (No_Exception_Handlers)
1375 Expand_Exception_Handlers (N);
1378 -- If local exceptions are being expanded, the previous call will
1379 -- have rewritten the construct as a block and reanalyzed it. No
1380 -- further expansion is needed.
1382 if Analyzed (N) then
1386 -- Add clean up actions if required
1388 if Nkind (Parent (N)) /= N_Package_Body
1389 and then Nkind (Parent (N)) /= N_Accept_Statement
1390 and then Nkind (Parent (N)) /= N_Extended_Return_Statement
1391 and then not Delay_Cleanups (Current_Scope)
1393 Expand_Cleanup_Actions (Parent (N));
1395 Set_First_Real_Statement (N, First (Statements (N)));
1397 end Expand_N_Handled_Sequence_Of_Statements;
1399 -------------------------------------
1400 -- Expand_N_Raise_Constraint_Error --
1401 -------------------------------------
1403 procedure Expand_N_Raise_Constraint_Error (N : Node_Id) is
1405 -- We adjust the condition to deal with the C/Fortran boolean case. This
1406 -- may well not be necessary, as all such conditions are generated by
1407 -- the expander and probably are all standard boolean, but who knows
1408 -- what strange optimization in future may require this adjustment!
1410 Adjust_Condition (Condition (N));
1412 -- Now deal with possible local raise handling
1414 Possible_Local_Raise (N, Standard_Constraint_Error);
1415 end Expand_N_Raise_Constraint_Error;
1417 ----------------------------------
1418 -- Expand_N_Raise_Program_Error --
1419 ----------------------------------
1421 procedure Expand_N_Raise_Program_Error (N : Node_Id) is
1423 -- We adjust the condition to deal with the C/Fortran boolean case. This
1424 -- may well not be necessary, as all such conditions are generated by
1425 -- the expander and probably are all standard boolean, but who knows
1426 -- what strange optimization in future may require this adjustment!
1428 Adjust_Condition (Condition (N));
1430 -- Now deal with possible local raise handling
1432 Possible_Local_Raise (N, Standard_Program_Error);
1433 end Expand_N_Raise_Program_Error;
1435 ------------------------------
1436 -- Expand_N_Raise_Statement --
1437 ------------------------------
1439 procedure Expand_N_Raise_Statement (N : Node_Id) is
1440 Loc : constant Source_Ptr := Sloc (N);
1447 -- Processing for locally handled exception (exclude reraise case)
1449 if Present (Name (N)) and then Nkind (Name (N)) = N_Identifier then
1451 or else Restriction_Active (No_Exception_Propagation)
1453 -- If we have a local handler, then note that this is potentially
1454 -- able to be transformed into a goto statement.
1456 H := Find_Local_Handler (Entity (Name (N)), N);
1459 if Local_Raise_Statements (H) = No_Elist then
1460 Set_Local_Raise_Statements (H, New_Elmt_List);
1463 -- Append the new entry if it is not there already. Sometimes
1464 -- we have situations where due to reexpansion, the same node
1465 -- is analyzed twice and would otherwise be added twice.
1467 Append_Unique_Elmt (N, Local_Raise_Statements (H));
1468 Set_Has_Local_Raise (H);
1470 -- If no local handler, then generate no propagation warning
1473 Warn_If_No_Propagation (N);
1479 -- If a string expression is present, then the raise statement is
1480 -- converted to a call:
1481 -- Raise_Exception (exception-name'Identity, string);
1482 -- and there is nothing else to do.
1484 if Present (Expression (N)) then
1486 -- Avoid passing exception-name'identity in runtimes in which this
1487 -- argument is not used. This avoids generating undefined references
1488 -- to these exceptions when compiling with no optimization
1490 if Configurable_Run_Time_On_Target
1491 and then (Restriction_Active (No_Exception_Handlers)
1493 Restriction_Active (No_Exception_Propagation))
1496 Make_Procedure_Call_Statement (Loc,
1497 Name => New_Occurrence_Of (RTE (RE_Raise_Exception), Loc),
1498 Parameter_Associations => New_List (
1499 New_Occurrence_Of (RTE (RE_Null_Id), Loc),
1503 Make_Procedure_Call_Statement (Loc,
1504 Name => New_Occurrence_Of (RTE (RE_Raise_Exception), Loc),
1505 Parameter_Associations => New_List (
1506 Make_Attribute_Reference (Loc,
1508 Attribute_Name => Name_Identity),
1516 -- Remaining processing is for the case where no string expression
1519 -- There is no expansion needed for statement "raise <exception>;" when
1520 -- compiling for the JVM since the JVM has a built-in exception
1521 -- mechanism. However we need to keep the expansion for "raise;"
1522 -- statements. See 4jexcept.ads for details.
1524 if Present (Name (N)) and then VM_Target /= No_VM then
1528 -- Don't expand a raise statement that does not come from source
1529 -- if we have already had configurable run-time violations, since
1530 -- most likely it will be junk cascaded nonsense.
1532 if Configurable_Run_Time_Violations > 0
1533 and then not Comes_From_Source (N)
1538 -- Convert explicit raise of Program_Error, Constraint_Error, and
1539 -- Storage_Error into the corresponding raise (in High_Integrity_Mode
1540 -- all other raises will get normal expansion and be disallowed,
1541 -- but this is also faster in all modes).
1543 if Present (Name (N)) and then Nkind (Name (N)) = N_Identifier then
1544 if Entity (Name (N)) = Standard_Constraint_Error then
1546 Make_Raise_Constraint_Error (Loc,
1547 Reason => CE_Explicit_Raise));
1551 elsif Entity (Name (N)) = Standard_Program_Error then
1553 Make_Raise_Program_Error (Loc,
1554 Reason => PE_Explicit_Raise));
1558 elsif Entity (Name (N)) = Standard_Storage_Error then
1560 Make_Raise_Storage_Error (Loc,
1561 Reason => SE_Explicit_Raise));
1567 -- Case of name present, in this case we expand raise name to
1569 -- Raise_Exception (name'Identity, location_string);
1571 -- where location_string identifies the file/line of the raise
1573 if Present (Name (N)) then
1575 Id : Entity_Id := Entity (Name (N));
1579 Build_Location_String (Loc);
1581 -- If the exception is a renaming, use the exception that it
1582 -- renames (which might be a predefined exception, e.g.).
1584 if Present (Renamed_Object (Id)) then
1585 Id := Renamed_Object (Id);
1588 -- Build a C-compatible string in case of no exception handlers,
1589 -- since this is what the last chance handler is expecting.
1591 if No_Exception_Handlers_Set then
1593 -- Generate an empty message if configuration pragma
1594 -- Suppress_Exception_Locations is set for this unit.
1596 if Opt.Exception_Locations_Suppressed then
1599 Name_Len := Name_Len + 1;
1602 Name_Buffer (Name_Len) := ASCII.NUL;
1605 if Opt.Exception_Locations_Suppressed then
1609 Str := String_From_Name_Buffer;
1611 -- For VMS exceptions, convert the raise into a call to
1612 -- lib$stop so it will be handled by __gnat_error_handler.
1614 if Is_VMS_Exception (Id) then
1616 Excep_Image : String_Id;
1620 if Present (Interface_Name (Id)) then
1621 Excep_Image := Strval (Interface_Name (Id));
1623 Get_Name_String (Chars (Id));
1625 Excep_Image := String_From_Name_Buffer;
1628 if Exception_Code (Id) /= No_Uint then
1630 Make_Integer_Literal (Loc, Exception_Code (Id));
1633 Unchecked_Convert_To (Standard_Integer,
1634 Make_Function_Call (Loc,
1635 Name => New_Occurrence_Of
1636 (RTE (RE_Import_Value), Loc),
1637 Parameter_Associations => New_List
1638 (Make_String_Literal (Loc,
1639 Strval => Excep_Image))));
1643 Make_Procedure_Call_Statement (Loc,
1645 New_Occurrence_Of (RTE (RE_Lib_Stop), Loc),
1646 Parameter_Associations => New_List (Cond)));
1647 Analyze_And_Resolve (Cond, Standard_Integer);
1650 -- Not VMS exception case, convert raise to call to the
1651 -- Raise_Exception routine.
1655 Make_Procedure_Call_Statement (Loc,
1656 Name => New_Occurrence_Of (RTE (RE_Raise_Exception), Loc),
1657 Parameter_Associations => New_List (
1658 Make_Attribute_Reference (Loc,
1660 Attribute_Name => Name_Identity),
1661 Make_String_Literal (Loc,
1666 -- Case of no name present (reraise). We rewrite the raise to:
1668 -- Reraise_Occurrence_Always (EO);
1670 -- where EO is the current exception occurrence. If the current handler
1671 -- does not have a choice parameter specification, then we provide one.
1674 -- Find innermost enclosing exception handler (there must be one,
1675 -- since the semantics has already verified that this raise statement
1676 -- is valid, and a raise with no arguments is only permitted in the
1677 -- context of an exception handler.
1679 Ehand := Parent (N);
1680 while Nkind (Ehand) /= N_Exception_Handler loop
1681 Ehand := Parent (Ehand);
1684 -- Make exception choice parameter if none present. Note that we do
1685 -- not need to put the entity on the entity chain, since no one will
1686 -- be referencing this entity by normal visibility methods.
1688 if No (Choice_Parameter (Ehand)) then
1689 E := Make_Defining_Identifier (Loc, New_Internal_Name ('E'));
1690 Set_Choice_Parameter (Ehand, E);
1691 Set_Ekind (E, E_Variable);
1692 Set_Etype (E, RTE (RE_Exception_Occurrence));
1693 Set_Scope (E, Current_Scope);
1696 -- Now rewrite the raise as a call to Reraise. A special case arises
1697 -- if this raise statement occurs in the context of a handler for
1698 -- all others (i.e. an at end handler). in this case we avoid
1699 -- the call to defer abort, cleanup routines are expected to be
1700 -- called in this case with aborts deferred.
1703 Ech : constant Node_Id := First (Exception_Choices (Ehand));
1707 if Nkind (Ech) = N_Others_Choice
1708 and then All_Others (Ech)
1710 Ent := RTE (RE_Reraise_Occurrence_No_Defer);
1712 Ent := RTE (RE_Reraise_Occurrence_Always);
1716 Make_Procedure_Call_Statement (Loc,
1717 Name => New_Occurrence_Of (Ent, Loc),
1718 Parameter_Associations => New_List (
1719 New_Occurrence_Of (Choice_Parameter (Ehand), Loc))));
1724 end Expand_N_Raise_Statement;
1726 ----------------------------------
1727 -- Expand_N_Raise_Storage_Error --
1728 ----------------------------------
1730 procedure Expand_N_Raise_Storage_Error (N : Node_Id) is
1732 -- We adjust the condition to deal with the C/Fortran boolean case. This
1733 -- may well not be necessary, as all such conditions are generated by
1734 -- the expander and probably are all standard boolean, but who knows
1735 -- what strange optimization in future may require this adjustment!
1737 Adjust_Condition (Condition (N));
1739 -- Now deal with possible local raise handling
1741 Possible_Local_Raise (N, Standard_Storage_Error);
1742 end Expand_N_Raise_Storage_Error;
1744 --------------------------
1745 -- Possible_Local_Raise --
1746 --------------------------
1748 procedure Possible_Local_Raise (N : Node_Id; E : Entity_Id) is
1750 -- Nothing to do if local raise optimization not active
1752 if not Debug_Flag_Dot_G
1753 and then not Restriction_Active (No_Exception_Propagation)
1758 -- Nothing to do if original node was an explicit raise, because in
1759 -- that case, we already generated the required warning for the raise.
1761 if Nkind (Original_Node (N)) = N_Raise_Statement then
1765 -- Otherwise see if we have a local handler for the exception
1768 H : constant Node_Id := Find_Local_Handler (E, N);
1771 -- If so, mark that it has a local raise
1774 Set_Has_Local_Raise (H, True);
1776 -- Otherwise, if the No_Exception_Propagation restriction is active
1777 -- and the warning is enabled, generate the appropriate warnings.
1779 elsif Warn_On_Non_Local_Exception
1780 and then Restriction_Active (No_Exception_Propagation)
1782 Warn_No_Exception_Propagation_Active (N);
1784 if Configurable_Run_Time_Mode then
1786 ("\?& may call Last_Chance_Handler", N, E);
1789 ("\?& may result in unhandled exception", N, E);
1793 end Possible_Local_Raise;
1795 ------------------------------
1796 -- Expand_N_Subprogram_Info --
1797 ------------------------------
1799 procedure Expand_N_Subprogram_Info (N : Node_Id) is
1800 Loc : constant Source_Ptr := Sloc (N);
1803 -- For now, we replace an Expand_N_Subprogram_Info node with an
1804 -- attribute reference that gives the address of the procedure.
1805 -- This is because gigi does not yet recognize this node, and
1806 -- for the initial targets, this is the right value anyway.
1809 Make_Attribute_Reference (Loc,
1810 Prefix => Identifier (N),
1811 Attribute_Name => Name_Code_Address));
1813 Analyze_And_Resolve (N, RTE (RE_Code_Loc));
1814 end Expand_N_Subprogram_Info;
1816 ------------------------
1817 -- Find_Local_Handler --
1818 ------------------------
1820 function Find_Local_Handler
1822 Nod : Node_Id) return Node_Id
1829 SSE : Scope_Stack_Entry renames Scope_Stack.Table (Scope_Stack.Last);
1830 -- This is used to test for wrapped actions below
1833 EHandle : Entity_Id;
1834 -- The entity Id's for the exception we are raising and handling, using
1835 -- the renamed exception if a Renamed_Entity is present.
1838 -- Never any local handler if all handlers removed
1840 if Debug_Flag_Dot_X then
1844 -- Get the exception we are raising, allowing for renaming
1846 ERaise := Get_Renamed_Entity (Ename);
1848 -- We need to check if the node we are looking at is contained in
1851 -- Loop to search up the tree
1857 -- If we get to the top of the tree, or to a subprogram, task, entry,
1858 -- protected body, or accept statement without having found a
1859 -- matching handler, then there is no local handler.
1862 or else Nkind (P) = N_Subprogram_Body
1863 or else Nkind (P) = N_Task_Body
1864 or else Nkind (P) = N_Protected_Body
1865 or else Nkind (P) = N_Entry_Body
1866 or else Nkind (P) = N_Accept_Statement
1870 -- Test for handled sequence of statements with at least one
1871 -- exception handler which might be the one we are looking for.
1873 elsif Nkind (P) = N_Handled_Sequence_Of_Statements
1874 and then Present (Exception_Handlers (P))
1876 -- Before we proceed we need to check if the node N is covered
1877 -- by the statement part of P rather than one of its exception
1878 -- handlers (an exception handler obviously does not cover its
1881 -- This test is more delicate than might be thought. It is not
1882 -- just a matter of checking the Statements (P), because the node
1883 -- might be waiting to be wrapped in a transient scope, in which
1884 -- case it will end up in the block statements, even though it
1885 -- is not there now.
1887 if Is_List_Member (N)
1888 and then (List_Containing (N) = Statements (P)
1890 List_Containing (N) = SSE.Actions_To_Be_Wrapped_Before
1892 List_Containing (N) = SSE.Actions_To_Be_Wrapped_After)
1894 -- Loop through exception handlers
1896 H := First (Exception_Handlers (P));
1897 while Present (H) loop
1899 -- Loop through choices in one handler
1901 C := First (Exception_Choices (H));
1902 while Present (C) loop
1904 -- Deal with others case
1906 if Nkind (C) = N_Others_Choice then
1908 -- Matching others handler, but we need to ensure
1909 -- there is no choice parameter. If there is, then we
1910 -- don't have a local handler after all (since we do
1911 -- not allow choice parameters for local handlers).
1913 if No (Choice_Parameter (H)) then
1919 -- If not others must be entity name
1921 elsif Nkind (C) /= N_Others_Choice then
1922 pragma Assert (Is_Entity_Name (C));
1923 pragma Assert (Present (Entity (C)));
1925 -- Get exception being handled, dealing with renaming
1927 EHandle := Get_Renamed_Entity (Entity (C));
1929 -- If match, then check choice parameter
1931 if ERaise = EHandle then
1932 if No (Choice_Parameter (H)) then
1950 end Find_Local_Handler;
1952 ---------------------------------
1953 -- Get_Local_Raise_Call_Entity --
1954 ---------------------------------
1956 -- Note: this is primary provided for use by the back end in generating
1957 -- calls to Local_Raise. But it would be too late in the back end to call
1958 -- RTE if this actually caused a load/analyze of the unit. So what we do
1959 -- is to ensure there is a dummy call to this function during front end
1960 -- processing so that the unit gets loaded then, and not later.
1962 Local_Raise_Call_Entity : Entity_Id;
1963 Local_Raise_Call_Entity_Set : Boolean := False;
1965 function Get_Local_Raise_Call_Entity return Entity_Id is
1967 if not Local_Raise_Call_Entity_Set then
1968 Local_Raise_Call_Entity_Set := True;
1970 if RTE_Available (RE_Local_Raise) then
1971 Local_Raise_Call_Entity := RTE (RE_Local_Raise);
1973 Local_Raise_Call_Entity := Empty;
1977 return Local_Raise_Call_Entity;
1978 end Get_Local_Raise_Call_Entity;
1980 -----------------------------
1981 -- Get_RT_Exception_Entity --
1982 -----------------------------
1984 function Get_RT_Exception_Entity (R : RT_Exception_Code) return Entity_Id is
1987 when RT_CE_Exceptions => return Standard_Constraint_Error;
1988 when RT_PE_Exceptions => return Standard_Program_Error;
1989 when RT_SE_Exceptions => return Standard_Storage_Error;
1991 end Get_RT_Exception_Entity;
1993 ----------------------
1994 -- Is_Non_Ada_Error --
1995 ----------------------
1997 function Is_Non_Ada_Error (E : Entity_Id) return Boolean is
1999 if not OpenVMS_On_Target then
2003 Get_Name_String (Chars (E));
2005 -- Note: it is a little irregular for the body of exp_ch11 to know
2006 -- the details of the encoding scheme for names, but on the other
2007 -- hand, gigi knows them, and this is for gigi's benefit anyway!
2009 if Name_Buffer (1 .. 30) /= "system__aux_dec__non_ada_error" then
2014 end Is_Non_Ada_Error;
2016 ----------------------------
2017 -- Warn_If_No_Propagation --
2018 ----------------------------
2020 procedure Warn_If_No_Propagation (N : Node_Id) is
2022 if Restriction_Active (No_Exception_Propagation)
2023 and then Warn_On_Non_Local_Exception
2025 Warn_No_Exception_Propagation_Active (N);
2027 if Configurable_Run_Time_Mode then
2029 ("\?Last_Chance_Handler will be called on exception", N);
2032 ("\?execution may raise unhandled exception", N);
2035 end Warn_If_No_Propagation;
2037 ------------------------------------------
2038 -- Warn_No_Exception_Propagation_Active --
2039 ------------------------------------------
2041 procedure Warn_No_Exception_Propagation_Active (N : Node_Id) is
2044 ("?pragma Restrictions (No_Exception_Propagation) in effect", N);
2045 end Warn_No_Exception_Propagation_Active;
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