1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, 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 three 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 -- These Push/Pop nodes are inhibited if No_Exception_Handlers is set
360 -- since they are useless in this case, and in CodePeer mode, where
361 -- they serve no purpose and can intefere with the analysis.
363 -- The back end must maintain three stacks, one for each exception case,
364 -- the Push node pushes an entry onto the corresponding stack, and Pop
365 -- node pops off the entry. Then instead of calling Rcheck_nn, if the
366 -- corresponding top stack entry has an non-empty label, a goto is
367 -- generated. This goto should be preceded by a call to Local_Raise as
370 -- An example of this transformation is as follows, given:
373 -- A : Integer range 1 .. 10;
377 -- when Constraint_Error =>
381 -- gets transformed to:
384 -- A : Integer range 1 .. 10;
391 -- %push_constraint_error_label (L1)
392 -- R1b : constant long_long_integer := long_long_integer?(b) +
393 -- long_long_integer?(c);
394 -- [constraint_error when
395 -- not (R1b in -16#8000_0000# .. 16#7FFF_FFFF#)
396 -- "overflow check failed"]
397 -- a := integer?(R1b);
398 -- %pop_constraint_error_Label
402 -- when constraint_error =>
406 -- goto L2; -- skip handler when exception not raised
407 -- <<L1>> -- target label for local exception
412 -- Note: the generated labels and goto statements all have the flag
413 -- Exception_Junk set True, so that Sem_Ch6.Check_Returns will ignore
414 -- this generated exception stuff when checking for missing return
415 -- statements (see circuitry in Check_Statement_Sequence).
417 -- Note: All of the processing described above occurs only if
418 -- restriction No_Exception_Propagation applies or debug flag .g is
421 CE_Locally_Handled
: Boolean := False;
422 SE_Locally_Handled
: Boolean := False;
423 PE_Locally_Handled
: Boolean := False;
424 -- These three flags indicate whether a handler for the corresponding
425 -- exception (CE=Constraint_Error, SE=Storage_Error, PE=Program_Error)
426 -- is present. If so the switch is set to True, the Exception_Label
427 -- field of the corresponding handler is set, and appropriate Push
428 -- and Pop nodes are inserted into the code.
430 Local_Expansion_Required
: Boolean := False;
431 -- Set True if we have at least one handler requiring local raise
432 -- expansion as described above.
434 procedure Expand_Local_Exception_Handlers
is
436 procedure Add_Exception_Label
(H
: Node_Id
);
437 -- H is an exception handler. First check for an Exception_Label
438 -- already allocated for H. If none, allocate one, set the field in
439 -- the handler node, add the label declaration, and set the flag
440 -- Local_Expansion_Required. Note: if Local_Raise_Not_OK is set
441 -- the call has no effect and Exception_Label is left empty.
443 procedure Add_Label_Declaration
(L
: Entity_Id
);
444 -- Add an implicit declaration of the given label to the declaration
445 -- list in the parent of the current sequence of handled statements.
448 Exc_Locally_Handled
: in out Boolean;
449 -- Flag indicating whether a local handler for this exception
450 -- has already been generated.
452 with function Make_Push_Label
(Loc
: Source_Ptr
) return Node_Id
;
453 -- Function to create a Push_xxx_Label node
455 with function Make_Pop_Label
(Loc
: Source_Ptr
) return Node_Id
;
456 -- Function to create a Pop_xxx_Label node
458 procedure Generate_Push_Pop
(H
: Node_Id
);
459 -- Common code for Generate_Push_Pop_xxx below, used to generate an
460 -- exception label and Push/Pop nodes for Constraint_Error,
461 -- Program_Error, or Storage_Error.
463 -------------------------
464 -- Add_Exception_Label --
465 -------------------------
467 procedure Add_Exception_Label
(H
: Node_Id
) is
469 if No
(Exception_Label
(H
))
470 and then not Local_Raise_Not_OK
(H
)
471 and then not Special_Exception_Package_Used
473 Local_Expansion_Required
:= True;
476 L
: constant Entity_Id
:= Make_Temporary
(Sloc
(H
), 'L');
478 Set_Exception_Label
(H
, L
);
479 Add_Label_Declaration
(L
);
482 end Add_Exception_Label
;
484 ---------------------------
485 -- Add_Label_Declaration --
486 ---------------------------
488 procedure Add_Label_Declaration
(L
: Entity_Id
) is
489 P
: constant Node_Id
:= Parent
(HSS
);
491 Decl_L
: constant Node_Id
:=
492 Make_Implicit_Label_Declaration
(Loc
,
493 Defining_Identifier
=> L
);
496 if Declarations
(P
) = No_List
then
497 Set_Declarations
(P
, Empty_List
);
500 Append
(Decl_L
, Declarations
(P
));
502 end Add_Label_Declaration
;
504 -----------------------
505 -- Generate_Push_Pop --
506 -----------------------
508 procedure Generate_Push_Pop
(H
: Node_Id
) is
510 if Restriction_Active
(No_Exception_Handlers
)
511 or else CodePeer_Mode
516 if Exc_Locally_Handled
then
519 Exc_Locally_Handled
:= True;
522 Add_Exception_Label
(H
);
525 F
: constant Node_Id
:= First
(Statements
(HSS
));
526 L
: constant Node_Id
:= Last
(Statements
(HSS
));
528 Push
: constant Node_Id
:= Make_Push_Label
(Sloc
(F
));
529 Pop
: constant Node_Id
:= Make_Pop_Label
(Sloc
(L
));
532 -- We make sure that a call to Get_Local_Raise_Call_Entity is
533 -- made during front end processing, so that when we need it
534 -- in the back end, it will already be available and loaded.
536 Discard_Node
(Get_Local_Raise_Call_Entity
);
538 -- Prepare and insert Push and Pop nodes
540 Set_Exception_Label
(Push
, Exception_Label
(H
));
541 Insert_Before
(F
, Push
);
544 Insert_After
(L
, Pop
);
547 end Generate_Push_Pop
;
549 -- Local declarations
551 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
552 Stmts
: List_Id
:= No_List
;
556 procedure Generate_Push_Pop_For_Constraint_Error
is
557 new Generate_Push_Pop
558 (Exc_Locally_Handled
=> CE_Locally_Handled
,
559 Make_Push_Label
=> Make_Push_Constraint_Error_Label
,
560 Make_Pop_Label
=> Make_Pop_Constraint_Error_Label
);
561 -- If no Push/Pop has been generated for CE yet, then set the flag
562 -- CE_Locally_Handled, allocate an Exception_Label for handler H (if
563 -- not already done), and generate Push/Pop nodes for the exception
564 -- label at the start and end of the statements of HSS.
566 procedure Generate_Push_Pop_For_Program_Error
is
567 new Generate_Push_Pop
568 (Exc_Locally_Handled
=> PE_Locally_Handled
,
569 Make_Push_Label
=> Make_Push_Program_Error_Label
,
570 Make_Pop_Label
=> Make_Pop_Program_Error_Label
);
571 -- If no Push/Pop has been generated for PE yet, then set the flag
572 -- PE_Locally_Handled, allocate an Exception_Label for handler H (if
573 -- not already done), and generate Push/Pop nodes for the exception
574 -- label at the start and end of the statements of HSS.
576 procedure Generate_Push_Pop_For_Storage_Error
is
577 new Generate_Push_Pop
578 (Exc_Locally_Handled
=> SE_Locally_Handled
,
579 Make_Push_Label
=> Make_Push_Storage_Error_Label
,
580 Make_Pop_Label
=> Make_Pop_Storage_Error_Label
);
581 -- If no Push/Pop has been generated for SE yet, then set the flag
582 -- SE_Locally_Handled, allocate an Exception_Label for handler H (if
583 -- not already done), and generate Push/Pop nodes for the exception
584 -- label at the start and end of the statements of HSS.
586 -- Start of processing for Expand_Local_Exception_Handlers
589 -- No processing if all exception handlers will get removed
591 if Debug_Flag_Dot_X
then
595 -- See for each handler if we have any local raises to expand
597 Handler
:= First_Non_Pragma
(Handlrs
);
598 while Present
(Handler
) loop
600 -- Note, we do not test Local_Raise_Not_OK here, because in the
601 -- case of Push/Pop generation we want to generate push with a
602 -- null label. The Add_Exception_Label routine has no effect if
603 -- Local_Raise_Not_OK is set, so this works as required.
605 if Present
(Local_Raise_Statements
(Handler
)) then
606 Add_Exception_Label
(Handler
);
609 -- If we are doing local raise to goto optimization (restriction
610 -- No_Exception_Propagation set or debug flag .g set), then check
611 -- to see if handler handles CE, PE, SE and if so generate the
612 -- appropriate push/pop sequence for the back end.
615 or else Restriction_Active
(No_Exception_Propagation
))
616 and then Has_Local_Raise
(Handler
)
618 Choice
:= First
(Exception_Choices
(Handler
));
619 while Present
(Choice
) loop
620 if Nkind
(Choice
) = N_Others_Choice
621 and then not All_Others
(Choice
)
623 Generate_Push_Pop_For_Constraint_Error
(Handler
);
624 Generate_Push_Pop_For_Program_Error
(Handler
);
625 Generate_Push_Pop_For_Storage_Error
(Handler
);
627 elsif Is_Entity_Name
(Choice
) then
628 Excep
:= Get_Renamed_Entity
(Entity
(Choice
));
630 if Excep
= Standard_Constraint_Error
then
631 Generate_Push_Pop_For_Constraint_Error
(Handler
);
632 elsif Excep
= Standard_Program_Error
then
633 Generate_Push_Pop_For_Program_Error
(Handler
);
634 elsif Excep
= Standard_Storage_Error
then
635 Generate_Push_Pop_For_Storage_Error
(Handler
);
643 Next_Non_Pragma
(Handler
);
646 -- Nothing to do if no handlers requiring the goto transformation
648 if not (Local_Expansion_Required
) then
652 -- Prepare to do the transformation
655 -- L3 is the label to exit the HSS
657 L3_Dent
: constant Entity_Id
:= Make_Temporary
(Loc
, 'L');
659 Labl_L3
: constant Node_Id
:=
661 Identifier
=> New_Occurrence_Of
(L3_Dent
, Loc
));
667 Set_Exception_Junk
(Labl_L3
);
668 Add_Label_Declaration
(L3_Dent
);
670 -- Wrap existing statements and handlers in an inner block
673 Make_Block_Statement
(Loc
,
674 Handled_Statement_Sequence
=> Relocate_Node
(HSS
));
675 Set_Exception_Junk
(Blk_Stm
);
678 Make_Handled_Sequence_Of_Statements
(Loc
,
679 Statements
=> New_List
(Blk_Stm
),
680 End_Label
=> Relocate_Node
(End_Label
(HSS
))));
682 -- Set block statement as analyzed, we don't want to actually call
683 -- Analyze on this block, it would cause a recursion in exception
684 -- handler processing which would mess things up.
686 Set_Analyzed
(Blk_Stm
);
688 -- Now loop through the exception handlers to deal with those that
689 -- are targets of local raise statements.
691 Handler
:= First_Non_Pragma
(Handlrs
);
692 while Present
(Handler
) loop
693 if Present
(Exception_Label
(Handler
)) then
695 -- This handler needs the goto expansion
698 Loc
: constant Source_Ptr
:= Sloc
(Handler
);
700 -- L1 is the start label for this handler
702 L1_Dent
: constant Entity_Id
:= Exception_Label
(Handler
);
704 Labl_L1
: constant Node_Id
:=
707 New_Occurrence_Of
(L1_Dent
, Loc
));
709 -- Jump to L1 to be used as replacement for the original
710 -- handler (used in the case where exception propagation
713 Name_L1
: constant Node_Id
:=
714 New_Occurrence_Of
(L1_Dent
, Loc
);
716 Goto_L1
: constant Node_Id
:=
717 Make_Goto_Statement
(Loc
,
720 -- Jump to L3 to be used at the end of handler
722 Name_L3
: constant Node_Id
:=
723 New_Occurrence_Of
(L3_Dent
, Loc
);
725 Goto_L3
: constant Node_Id
:=
726 Make_Goto_Statement
(Loc
,
729 H_Stmts
: constant List_Id
:= Statements
(Handler
);
732 Set_Exception_Junk
(Labl_L1
);
733 Set_Exception_Junk
(Goto_L3
);
735 -- Note: we do NOT set Exception_Junk in Goto_L1, since
736 -- this is a real transfer of control that we want the
737 -- Sem_Ch6.Check_Returns procedure to recognize properly.
739 -- Replace handler by a goto L1. We can mark this as
740 -- analyzed since it is fully formed, and we don't
741 -- want it going through any further checks. We save
742 -- the last statement location in the goto L1 node for
743 -- the benefit of Sem_Ch6.Check_Returns.
745 Set_Statements
(Handler
, New_List
(Goto_L1
));
746 Set_Analyzed
(Goto_L1
);
747 Set_Etype
(Name_L1
, Standard_Void_Type
);
749 -- Now replace all the raise statements by goto L1
751 if Present
(Local_Raise_Statements
(Handler
)) then
752 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
753 while Present
(Relmt
) loop
755 Raise_S
: constant Node_Id
:= Node
(Relmt
);
756 RLoc
: constant Source_Ptr
:= Sloc
(Raise_S
);
757 Name_L1
: constant Node_Id
:=
758 New_Occurrence_Of
(L1_Dent
, Loc
);
759 Goto_L1
: constant Node_Id
:=
760 Make_Goto_Statement
(RLoc
,
764 -- Replace raise by goto L1
766 Set_Analyzed
(Goto_L1
);
767 Set_Etype
(Name_L1
, Standard_Void_Type
);
768 Replace_Raise_By_Goto
(Raise_S
, Goto_L1
);
775 -- Add a goto L3 at end of statement list in block. The
776 -- first time, this is what skips over the exception
777 -- handlers in the normal case. Subsequent times, it
778 -- terminates the execution of the previous handler code,
779 -- and skips subsequent handlers.
781 Stmts
:= Statements
(HSS
);
783 Insert_After
(Last
(Stmts
), Goto_L3
);
784 Set_Analyzed
(Goto_L3
);
785 Set_Etype
(Name_L3
, Standard_Void_Type
);
787 -- Now we drop the label that marks the handler start,
788 -- followed by the statements of the handler.
790 Set_Etype
(Identifier
(Labl_L1
), Standard_Void_Type
);
792 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L1
);
795 Loc
: constant Source_Ptr
:= Sloc
(First
(H_Stmts
));
796 Blk
: constant Node_Id
:=
797 Make_Block_Statement
(Loc
,
798 Handled_Statement_Sequence
=>
799 Make_Handled_Sequence_Of_Statements
(Loc
,
800 Statements
=> H_Stmts
));
802 Set_Exception_Junk
(Blk
);
803 Insert_After_And_Analyze
(Last
(Stmts
), Blk
);
807 -- Here if we have local raise statements but the handler is
808 -- not suitable for processing with a local raise. In this
809 -- case we have to generate possible diagnostics.
811 elsif Has_Local_Raise
(Handler
)
812 and then Local_Raise_Statements
(Handler
) /= No_Elist
814 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
815 while Present
(Relmt
) loop
816 Warn_If_No_Propagation
(Node
(Relmt
));
824 -- Only remaining step is to drop the L3 label and we are done
826 Set_Etype
(Identifier
(Labl_L3
), Standard_Void_Type
);
828 -- If we had at least one handler, then we drop the label after
829 -- the last statement of that handler.
831 if Stmts
/= No_List
then
832 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L3
);
834 -- Otherwise we have removed all the handlers (this results from
835 -- use of pragma Restrictions (No_Exception_Propagation), and we
836 -- drop the label at the end of the statements of the HSS.
839 Insert_After_And_Analyze
(Last
(Statements
(HSS
)), Labl_L3
);
844 end Expand_Local_Exception_Handlers
;
846 -----------------------------
847 -- Prepend_Call_To_Handler --
848 -----------------------------
850 procedure Prepend_Call_To_Handler
852 Args
: List_Id
:= No_List
)
854 Ent
: constant Entity_Id
:= RTE
(Proc
);
857 -- If we have no Entity, then we are probably in no run time mode or
858 -- some weird error has occurred. In either case do nothing. Note use
859 -- of No_Location to hide this code from the debugger, so single
860 -- stepping doesn't jump back and forth.
862 if Present
(Ent
) then
864 Call
: constant Node_Id
:=
865 Make_Procedure_Call_Statement
(No_Location
,
866 Name
=> New_Occurrence_Of
(RTE
(Proc
), No_Location
),
867 Parameter_Associations
=> Args
);
870 Prepend_To
(Statements
(Handler
), Call
);
871 Analyze
(Call
, Suppress
=> All_Checks
);
874 end Prepend_Call_To_Handler
;
876 ---------------------------
877 -- Replace_Raise_By_Goto --
878 ---------------------------
880 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
) is
881 Loc
: constant Source_Ptr
:= Sloc
(Raise_S
);
888 -- If we have a null statement, it means that there is no replacement
889 -- needed (typically this results from a suppressed check).
891 if Nkind
(Raise_S
) = N_Null_Statement
then
894 -- Test for Raise_xxx_Error
896 elsif Nkind
(Raise_S
) = N_Raise_Constraint_Error
then
897 Excep
:= Standard_Constraint_Error
;
898 Cond
:= Condition
(Raise_S
);
900 elsif Nkind
(Raise_S
) = N_Raise_Storage_Error
then
901 Excep
:= Standard_Storage_Error
;
902 Cond
:= Condition
(Raise_S
);
904 elsif Nkind
(Raise_S
) = N_Raise_Program_Error
then
905 Excep
:= Standard_Program_Error
;
906 Cond
:= Condition
(Raise_S
);
908 -- The only other possibility is a node that is or used to be a
909 -- simple raise statement.
912 Orig
:= Original_Node
(Raise_S
);
913 pragma Assert
(Nkind
(Orig
) = N_Raise_Statement
914 and then Present
(Name
(Orig
))
915 and then No
(Expression
(Orig
)));
916 Excep
:= Entity
(Name
(Orig
));
920 -- Here Excep is the exception to raise, and Cond is the condition
921 -- First prepare the call to Local_Raise (excep'address).
923 if RTE_Available
(RE_Local_Raise
) then
925 Make_Procedure_Call_Statement
(Loc
,
926 Name
=> New_Occurrence_Of
(RTE
(RE_Local_Raise
), Loc
),
927 Parameter_Associations
=> New_List
(
928 Unchecked_Convert_To
(RTE
(RE_Address
),
929 Make_Attribute_Reference
(Loc
,
930 Prefix
=> New_Occurrence_Of
(Excep
, Loc
),
931 Attribute_Name
=> Name_Identity
))));
933 -- Use null statement if Local_Raise not available
937 Make_Null_Statement
(Loc
);
940 -- If there is no condition, we rewrite as
943 -- Local_Raise (excep'Identity);
949 Make_Block_Statement
(Loc
,
950 Handled_Statement_Sequence
=>
951 Make_Handled_Sequence_Of_Statements
(Loc
,
952 Statements
=> New_List
(LR
, Goto_L1
))));
953 Set_Exception_Junk
(Raise_S
);
955 -- If there is a condition, we rewrite as
958 -- Local_Raise (excep'Identity);
964 Make_If_Statement
(Loc
,
966 Then_Statements
=> New_List
(LR
, Goto_L1
)));
970 end Replace_Raise_By_Goto
;
972 -- Start of processing for Expand_Exception_Handlers
975 Expand_Local_Exception_Handlers
;
977 -- Loop through handlers
979 Handler
:= First_Non_Pragma
(Handlrs
);
980 Handler_Loop
: while Present
(Handler
) loop
981 Process_Statements_For_Controlled_Objects
(Handler
);
983 Next_Handler
:= Next_Non_Pragma
(Handler
);
985 -- Remove source handler if gnat debug flag .x is set
987 if Debug_Flag_Dot_X
and then Comes_From_Source
(Handler
) then
990 -- Remove handler if no exception propagation, generating a warning
991 -- if a source generated handler was not the target of a local raise.
994 if Restriction_Active
(No_Exception_Propagation
)
995 and then not Has_Local_Raise
(Handler
)
996 and then Comes_From_Source
(Handler
)
997 and then Warn_On_Non_Local_Exception
999 Warn_No_Exception_Propagation_Active
(Handler
);
1001 ("\?this handler can never be entered, and has been removed",
1005 if No_Exception_Propagation_Active
then
1008 -- Exception handler is active and retained and must be processed
1011 -- If an exception occurrence is present, then we must declare
1012 -- it and initialize it from the value stored in the TSD
1015 -- name : Exception_Occurrence;
1017 -- Save_Occurrence (name, Get_Current_Excep.all)
1021 if Present
(Choice_Parameter
(Handler
)) then
1023 Cparm
: constant Entity_Id
:= Choice_Parameter
(Handler
);
1024 Cloc
: constant Source_Ptr
:= Sloc
(Cparm
);
1025 Hloc
: constant Source_Ptr
:= Sloc
(Handler
);
1029 -- Note use of No_Location to hide this code from the
1030 -- debugger, so single stepping doesn't jump back and
1034 Make_Procedure_Call_Statement
(No_Location
,
1036 New_Occurrence_Of
(RTE
(RE_Save_Occurrence
),
1038 Parameter_Associations
=> New_List
(
1039 New_Occurrence_Of
(Cparm
, Cloc
),
1040 Make_Explicit_Dereference
(No_Location
,
1041 Make_Function_Call
(No_Location
,
1042 Name
=> Make_Explicit_Dereference
(No_Location
,
1044 (RTE
(RE_Get_Current_Excep
),
1047 Mark_Rewrite_Insertion
(Save
);
1048 Prepend
(Save
, Statements
(Handler
));
1051 Make_Object_Declaration
1053 Defining_Identifier
=> Cparm
,
1054 Object_Definition
=>
1056 (RTE
(RE_Exception_Occurrence
), Cloc
));
1057 Set_No_Initialization
(Obj_Decl
, True);
1060 Make_Exception_Handler
(Hloc
,
1061 Choice_Parameter
=> Empty
,
1062 Exception_Choices
=> Exception_Choices
(Handler
),
1064 Statements
=> New_List
(
1065 Make_Block_Statement
(Hloc
,
1066 Declarations
=> New_List
(Obj_Decl
),
1067 Handled_Statement_Sequence
=>
1068 Make_Handled_Sequence_Of_Statements
(Hloc
,
1069 Statements
=> Statements
(Handler
))))));
1071 -- Local raise statements can't occur, since exception
1072 -- handlers with choice parameters are not allowed when
1073 -- No_Exception_Propagation applies, so set attributes
1076 Set_Local_Raise_Statements
(Handler
, No_Elist
);
1077 Set_Local_Raise_Not_OK
(Handler
);
1080 (Statements
(Handler
), Suppress
=> All_Checks
);
1084 -- The processing at this point is rather different for the JVM
1085 -- case, so we completely separate the processing.
1087 -- For the VM case, we unconditionally call Update_Exception,
1088 -- passing a call to the intrinsic Current_Target_Exception
1089 -- (see JVM/.NET versions of Ada.Exceptions for details).
1091 if VM_Target
/= No_VM
then
1093 Arg
: constant Node_Id
:=
1094 Make_Function_Call
(Loc
,
1097 (RTE
(RE_Current_Target_Exception
), Loc
));
1099 Prepend_Call_To_Handler
1100 (RE_Update_Exception
, New_List
(Arg
));
1103 -- For the normal case, we have to worry about the state of
1104 -- abort deferral. Generally, we defer abort during runtime
1105 -- handling of exceptions. When control is passed to the
1106 -- handler, then in the normal case we undefer aborts. In
1107 -- any case this entire handling is relevant only if aborts
1111 and then Exception_Mechanism
/= Back_End_Exceptions
1113 -- There are some special cases in which we do not do the
1114 -- undefer. In particular a finalization (AT END) handler
1115 -- wants to operate with aborts still deferred.
1117 -- We also suppress the call if this is the special handler
1118 -- for Abort_Signal, since if we are aborting, we want to
1119 -- keep aborts deferred (one abort is enough).
1121 -- If abort really needs to be deferred the expander must
1122 -- add this call explicitly, see
1123 -- Expand_N_Asynchronous_Select.
1126 Nkind
(First
(Exception_Choices
(Handler
))) =
1130 or else Entity
(First
(Exception_Choices
(Handler
))) /=
1135 All_Others
(First
(Exception_Choices
(Handler
))))
1137 Prepend_Call_To_Handler
(RE_Abort_Undefer
);
1143 Handler
:= Next_Handler
;
1144 end loop Handler_Loop
;
1146 -- If all handlers got removed, then remove the list. Note we cannot
1147 -- reference HSS here, since expanding local handlers may have buried
1148 -- the handlers in an inner block.
1150 if Is_Empty_List
(Handlrs
) then
1151 Set_Exception_Handlers
(Parent
(Handlrs
), No_List
);
1153 end Expand_Exception_Handlers
;
1155 ------------------------------------
1156 -- Expand_N_Exception_Declaration --
1157 ------------------------------------
1160 -- exceptE : constant String := "A.B.EXCEP"; -- static data
1161 -- except : exception_data := (
1162 -- Handled_By_Other => False,
1164 -- Name_Length => exceptE'Length,
1165 -- Full_Name => exceptE'Address,
1166 -- HTable_Ptr => null,
1167 -- Import_Code => 0,
1168 -- Raise_Hook => null,
1171 -- (protecting test only needed if not at library level)
1173 -- exceptF : Boolean := True -- static data
1175 -- exceptF := False;
1176 -- Register_Exception (except'Unchecked_Access);
1179 procedure Expand_N_Exception_Declaration
(N
: Node_Id
) is
1180 Loc
: constant Source_Ptr
:= Sloc
(N
);
1181 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
1182 L
: List_Id
:= New_List
;
1183 Flag_Id
: Entity_Id
;
1185 Name_Exname
: constant Name_Id
:= New_External_Name
(Chars
(Id
), 'E');
1186 Exname
: constant Node_Id
:=
1187 Make_Defining_Identifier
(Loc
, Name_Exname
);
1189 procedure Force_Static_Allocation_Of_Referenced_Objects
1190 (Aggregate
: Node_Id
);
1191 -- A specialized solution to one particular case of an ugly problem
1193 -- The given aggregate includes an Unchecked_Conversion as one of the
1194 -- component values. The call to Analyze_And_Resolve below ends up
1195 -- calling Exp_Ch4.Expand_N_Unchecked_Type_Conversion, which may decide
1196 -- to introduce a (constant) temporary and then obtain the component
1197 -- value by evaluating the temporary.
1199 -- In the case of an exception declared within a subprogram (or any
1200 -- other dynamic scope), this is a bad transformation. The exception
1201 -- object is marked as being Statically_Allocated but the temporary is
1202 -- not. If the initial value of a Statically_Allocated declaration
1203 -- references a dynamically allocated object, this prevents static
1204 -- initialization of the object.
1206 -- We cope with this here by marking the temporary Statically_Allocated.
1207 -- It might seem cleaner to generalize this utility and then use it to
1208 -- enforce a rule that the entities referenced in the declaration of any
1209 -- "hoisted" (i.e., Is_Statically_Allocated and not Is_Library_Level)
1210 -- entity must also be either Library_Level or hoisted. It turns out
1211 -- that this would be incompatible with the current treatment of an
1212 -- object which is local to a subprogram, subject to an Export pragma,
1213 -- not subject to an address clause, and whose declaration contains
1214 -- references to other local (non-hoisted) objects (e.g., in the initial
1215 -- value expression).
1217 ---------------------------------------------------
1218 -- Force_Static_Allocation_Of_Referenced_Objects --
1219 ---------------------------------------------------
1221 procedure Force_Static_Allocation_Of_Referenced_Objects
1222 (Aggregate
: Node_Id
)
1224 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
;
1225 -- If the given node references a dynamically allocated object, then
1226 -- correct the declaration of the object.
1232 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
is
1234 if Nkind
(N
) in N_Has_Entity
1235 and then Present
(Entity
(N
))
1236 and then not Is_Library_Level_Entity
(Entity
(N
))
1238 -- Note: the following test is not needed but it seems cleaner
1239 -- to do this test (this would be more important if procedure
1240 -- Force_Static_Allocation_Of_Referenced_Objects recursively
1241 -- traversed the declaration of an entity after marking it as
1242 -- statically allocated).
1244 and then not Is_Statically_Allocated
(Entity
(N
))
1246 Set_Is_Statically_Allocated
(Entity
(N
));
1252 procedure Fixup_Tree
is new Traverse_Proc
(Fixup_Node
);
1254 -- Start of processing for Force_Static_Allocation_Of_Referenced_Objects
1257 Fixup_Tree
(Aggregate
);
1258 end Force_Static_Allocation_Of_Referenced_Objects
;
1260 -- Start of processing for Expand_N_Exception_Declaration
1263 -- There is no expansion needed when compiling for the JVM since the
1264 -- JVM has a built-in exception mechanism. See cil/gnatlib/a-except.ads
1267 if VM_Target
/= No_VM
then
1271 -- Definition of the external name: nam : constant String := "A.B.NAME";
1274 Make_Object_Declaration
(Loc
,
1275 Defining_Identifier
=> Exname
,
1276 Constant_Present
=> True,
1277 Object_Definition
=> New_Occurrence_Of
(Standard_String
, Loc
),
1279 Make_String_Literal
(Loc
,
1280 Strval
=> Fully_Qualified_Name_String
(Id
))));
1282 Set_Is_Statically_Allocated
(Exname
);
1284 -- Create the aggregate list for type Standard.Exception_Type:
1285 -- Handled_By_Other component: False
1287 Append_To
(L
, New_Occurrence_Of
(Standard_False
, Loc
));
1289 -- Lang component: 'A'
1292 Make_Character_Literal
(Loc
,
1294 Char_Literal_Value
=> UI_From_Int
(Character'Pos ('A'))));
1296 -- Name_Length component: Nam'Length
1299 Make_Attribute_Reference
(Loc
,
1300 Prefix
=> New_Occurrence_Of
(Exname
, Loc
),
1301 Attribute_Name
=> Name_Length
));
1303 -- Full_Name component: Standard.A_Char!(Nam'Address)
1305 Append_To
(L
, Unchecked_Convert_To
(Standard_A_Char
,
1306 Make_Attribute_Reference
(Loc
,
1307 Prefix
=> New_Occurrence_Of
(Exname
, Loc
),
1308 Attribute_Name
=> Name_Address
)));
1310 -- HTable_Ptr component: null
1312 Append_To
(L
, Make_Null
(Loc
));
1314 -- Import_Code component: 0
1316 Append_To
(L
, Make_Integer_Literal
(Loc
, 0));
1318 -- Raise_Hook component: null
1320 Append_To
(L
, Make_Null
(Loc
));
1322 Set_Expression
(N
, Make_Aggregate
(Loc
, Expressions
=> L
));
1323 Analyze_And_Resolve
(Expression
(N
), Etype
(Id
));
1325 Force_Static_Allocation_Of_Referenced_Objects
(Expression
(N
));
1327 -- Register_Exception (except'Unchecked_Access);
1329 if not No_Exception_Handlers_Set
1330 and then not Restriction_Active
(No_Exception_Registration
)
1333 Make_Procedure_Call_Statement
(Loc
,
1334 Name
=> New_Occurrence_Of
(RTE
(RE_Register_Exception
), Loc
),
1335 Parameter_Associations
=> New_List
(
1336 Unchecked_Convert_To
(RTE
(RE_Exception_Data_Ptr
),
1337 Make_Attribute_Reference
(Loc
,
1338 Prefix
=> New_Occurrence_Of
(Id
, Loc
),
1339 Attribute_Name
=> Name_Unrestricted_Access
)))));
1341 Set_Register_Exception_Call
(Id
, First
(L
));
1343 if not Is_Library_Level_Entity
(Id
) then
1344 Flag_Id
:= Make_Defining_Identifier
(Loc
,
1345 New_External_Name
(Chars
(Id
), 'F'));
1348 Make_Object_Declaration
(Loc
,
1349 Defining_Identifier
=> Flag_Id
,
1350 Object_Definition
=>
1351 New_Occurrence_Of
(Standard_Boolean
, Loc
),
1353 New_Occurrence_Of
(Standard_True
, Loc
)));
1355 Set_Is_Statically_Allocated
(Flag_Id
);
1358 Make_Assignment_Statement
(Loc
,
1359 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1360 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
1362 Insert_After_And_Analyze
(N
,
1363 Make_Implicit_If_Statement
(N
,
1364 Condition
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1365 Then_Statements
=> L
));
1368 Insert_List_After_And_Analyze
(N
, L
);
1371 end Expand_N_Exception_Declaration
;
1373 ---------------------------------------------
1374 -- Expand_N_Handled_Sequence_Of_Statements --
1375 ---------------------------------------------
1377 procedure Expand_N_Handled_Sequence_Of_Statements
(N
: Node_Id
) is
1379 -- Expand exception handlers
1381 if Present
(Exception_Handlers
(N
))
1382 and then not Restriction_Active
(No_Exception_Handlers
)
1384 Expand_Exception_Handlers
(N
);
1387 -- If local exceptions are being expanded, the previous call will
1388 -- have rewritten the construct as a block and reanalyzed it. No
1389 -- further expansion is needed.
1391 if Analyzed
(N
) then
1395 -- Add clean up actions if required
1397 if Nkind
(Parent
(N
)) /= N_Package_Body
1398 and then Nkind
(Parent
(N
)) /= N_Accept_Statement
1399 and then Nkind
(Parent
(N
)) /= N_Extended_Return_Statement
1400 and then not Delay_Cleanups
(Current_Scope
)
1402 Expand_Cleanup_Actions
(Parent
(N
));
1404 Set_First_Real_Statement
(N
, First
(Statements
(N
)));
1406 end Expand_N_Handled_Sequence_Of_Statements
;
1408 -------------------------------------
1409 -- Expand_N_Raise_Constraint_Error --
1410 -------------------------------------
1412 procedure Expand_N_Raise_Constraint_Error
(N
: Node_Id
) is
1414 -- We adjust the condition to deal with the C/Fortran boolean case. This
1415 -- may well not be necessary, as all such conditions are generated by
1416 -- the expander and probably are all standard boolean, but who knows
1417 -- what strange optimization in future may require this adjustment!
1419 Adjust_Condition
(Condition
(N
));
1421 -- Now deal with possible local raise handling
1423 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
1424 end Expand_N_Raise_Constraint_Error
;
1426 ----------------------------------
1427 -- Expand_N_Raise_Program_Error --
1428 ----------------------------------
1430 procedure Expand_N_Raise_Program_Error
(N
: Node_Id
) is
1432 -- We adjust the condition to deal with the C/Fortran boolean case. This
1433 -- may well not be necessary, as all such conditions are generated by
1434 -- the expander and probably are all standard boolean, but who knows
1435 -- what strange optimization in future may require this adjustment!
1437 Adjust_Condition
(Condition
(N
));
1439 -- Now deal with possible local raise handling
1441 Possible_Local_Raise
(N
, Standard_Program_Error
);
1442 end Expand_N_Raise_Program_Error
;
1444 ------------------------------
1445 -- Expand_N_Raise_Statement --
1446 ------------------------------
1448 procedure Expand_N_Raise_Statement
(N
: Node_Id
) is
1449 Loc
: constant Source_Ptr
:= Sloc
(N
);
1457 -- Processing for locally handled exception (exclude reraise case)
1459 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1461 or else Restriction_Active
(No_Exception_Propagation
)
1463 -- If we have a local handler, then note that this is potentially
1464 -- able to be transformed into a goto statement.
1466 H
:= Find_Local_Handler
(Entity
(Name
(N
)), N
);
1469 if Local_Raise_Statements
(H
) = No_Elist
then
1470 Set_Local_Raise_Statements
(H
, New_Elmt_List
);
1473 -- Append the new entry if it is not there already. Sometimes
1474 -- we have situations where due to reexpansion, the same node
1475 -- is analyzed twice and would otherwise be added twice.
1477 Append_Unique_Elmt
(N
, Local_Raise_Statements
(H
));
1478 Set_Has_Local_Raise
(H
);
1480 -- If no local handler, then generate no propagation warning
1483 Warn_If_No_Propagation
(N
);
1489 -- If a string expression is present, then the raise statement is
1490 -- converted to a call:
1491 -- Raise_Exception (exception-name'Identity, string);
1492 -- and there is nothing else to do.
1494 if Present
(Expression
(N
)) then
1496 -- Avoid passing exception-name'identity in runtimes in which this
1497 -- argument is not used. This avoids generating undefined references
1498 -- to these exceptions when compiling with no optimization
1500 if Configurable_Run_Time_On_Target
1501 and then (Restriction_Active
(No_Exception_Handlers
)
1503 Restriction_Active
(No_Exception_Propagation
))
1506 Make_Procedure_Call_Statement
(Loc
,
1507 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1508 Parameter_Associations
=> New_List
(
1509 New_Occurrence_Of
(RTE
(RE_Null_Id
), Loc
),
1513 Make_Procedure_Call_Statement
(Loc
,
1514 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1515 Parameter_Associations
=> New_List
(
1516 Make_Attribute_Reference
(Loc
,
1518 Attribute_Name
=> Name_Identity
),
1526 -- Remaining processing is for the case where no string expression is
1529 -- Don't expand a raise statement that does not come from source if we
1530 -- have already had configurable run-time violations, since most likely
1531 -- it will be junk cascaded nonsense.
1533 if Configurable_Run_Time_Violations
> 0
1534 and then not Comes_From_Source
(N
)
1539 -- Convert explicit raise of Program_Error, Constraint_Error, and
1540 -- Storage_Error into the corresponding raise (in High_Integrity_Mode
1541 -- all other raises will get normal expansion and be disallowed,
1542 -- but this is also faster in all modes). Propagate Comes_From_Source
1543 -- flag to the new node.
1545 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1546 Src
:= Comes_From_Source
(N
);
1548 if Entity
(Name
(N
)) = Standard_Constraint_Error
then
1550 Make_Raise_Constraint_Error
(Loc
, Reason
=> CE_Explicit_Raise
));
1551 Set_Comes_From_Source
(N
, Src
);
1555 elsif Entity
(Name
(N
)) = Standard_Program_Error
then
1557 Make_Raise_Program_Error
(Loc
, Reason
=> PE_Explicit_Raise
));
1558 Set_Comes_From_Source
(N
, Src
);
1562 elsif Entity
(Name
(N
)) = Standard_Storage_Error
then
1564 Make_Raise_Storage_Error
(Loc
, Reason
=> SE_Explicit_Raise
));
1565 Set_Comes_From_Source
(N
, Src
);
1571 -- Case of name present, in this case we expand raise name to
1573 -- Raise_Exception (name'Identity, location_string);
1575 -- where location_string identifies the file/line of the raise
1577 if Present
(Name
(N
)) then
1579 Id
: Entity_Id
:= Entity
(Name
(N
));
1583 Build_Location_String
(Loc
);
1585 -- If the exception is a renaming, use the exception that it
1586 -- renames (which might be a predefined exception, e.g.).
1588 if Present
(Renamed_Object
(Id
)) then
1589 Id
:= Renamed_Object
(Id
);
1592 -- Build a C-compatible string in case of no exception handlers,
1593 -- since this is what the last chance handler is expecting.
1595 if No_Exception_Handlers_Set
then
1597 -- Generate an empty message if configuration pragma
1598 -- Suppress_Exception_Locations is set for this unit.
1600 if Opt
.Exception_Locations_Suppressed
then
1603 Name_Len
:= Name_Len
+ 1;
1606 Name_Buffer
(Name_Len
) := ASCII
.NUL
;
1609 if Opt
.Exception_Locations_Suppressed
then
1613 Str
:= String_From_Name_Buffer
;
1615 -- For VMS exceptions, convert the raise into a call to
1616 -- lib$stop so it will be handled by __gnat_error_handler.
1618 if Is_VMS_Exception
(Id
) then
1620 Excep_Image
: String_Id
;
1624 if Present
(Interface_Name
(Id
)) then
1625 Excep_Image
:= Strval
(Interface_Name
(Id
));
1627 Get_Name_String
(Chars
(Id
));
1629 Excep_Image
:= String_From_Name_Buffer
;
1632 if Exception_Code
(Id
) /= No_Uint
then
1634 Make_Integer_Literal
(Loc
, Exception_Code
(Id
));
1637 Unchecked_Convert_To
(Standard_Integer
,
1638 Make_Function_Call
(Loc
,
1639 Name
=> New_Occurrence_Of
1640 (RTE
(RE_Import_Value
), Loc
),
1641 Parameter_Associations
=> New_List
1642 (Make_String_Literal
(Loc
,
1643 Strval
=> Excep_Image
))));
1647 Make_Procedure_Call_Statement
(Loc
,
1649 New_Occurrence_Of
(RTE
(RE_Lib_Stop
), Loc
),
1650 Parameter_Associations
=> New_List
(Cond
)));
1651 Analyze_And_Resolve
(Cond
, Standard_Integer
);
1654 -- Not VMS exception case, convert raise to call to the
1655 -- Raise_Exception routine.
1659 Make_Procedure_Call_Statement
(Loc
,
1660 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1661 Parameter_Associations
=> New_List
(
1662 Make_Attribute_Reference
(Loc
,
1664 Attribute_Name
=> Name_Identity
),
1665 Make_String_Literal
(Loc
,
1670 -- Case of no name present (reraise). We rewrite the raise to:
1672 -- Reraise_Occurrence_Always (EO);
1674 -- where EO is the current exception occurrence. If the current handler
1675 -- does not have a choice parameter specification, then we provide one.
1678 -- Bypass expansion to a run-time call when back-end exception
1679 -- handling is active, unless the target is a VM, CodePeer or
1680 -- GNATprove. In CodePeer, raising an exception is treated as an
1681 -- error, while in GNATprove all code with exceptions falls outside
1682 -- the subset of code which can be formally analyzed.
1684 if VM_Target
= No_VM
1685 and then not CodePeer_Mode
1686 and then Exception_Mechanism
= Back_End_Exceptions
1691 -- Find innermost enclosing exception handler (there must be one,
1692 -- since the semantics has already verified that this raise statement
1693 -- is valid, and a raise with no arguments is only permitted in the
1694 -- context of an exception handler.
1696 Ehand
:= Parent
(N
);
1697 while Nkind
(Ehand
) /= N_Exception_Handler
loop
1698 Ehand
:= Parent
(Ehand
);
1701 -- Make exception choice parameter if none present. Note that we do
1702 -- not need to put the entity on the entity chain, since no one will
1703 -- be referencing this entity by normal visibility methods.
1705 if No
(Choice_Parameter
(Ehand
)) then
1706 E
:= Make_Temporary
(Loc
, 'E');
1707 Set_Choice_Parameter
(Ehand
, E
);
1708 Set_Ekind
(E
, E_Variable
);
1709 Set_Etype
(E
, RTE
(RE_Exception_Occurrence
));
1710 Set_Scope
(E
, Current_Scope
);
1713 -- Now rewrite the raise as a call to Reraise. A special case arises
1714 -- if this raise statement occurs in the context of a handler for
1715 -- all others (i.e. an at end handler). in this case we avoid
1716 -- the call to defer abort, cleanup routines are expected to be
1717 -- called in this case with aborts deferred.
1720 Ech
: constant Node_Id
:= First
(Exception_Choices
(Ehand
));
1724 if Nkind
(Ech
) = N_Others_Choice
1725 and then All_Others
(Ech
)
1727 Ent
:= RTE
(RE_Reraise_Occurrence_No_Defer
);
1729 Ent
:= RTE
(RE_Reraise_Occurrence_Always
);
1733 Make_Procedure_Call_Statement
(Loc
,
1734 Name
=> New_Occurrence_Of
(Ent
, Loc
),
1735 Parameter_Associations
=> New_List
(
1736 New_Occurrence_Of
(Choice_Parameter
(Ehand
), Loc
))));
1741 end Expand_N_Raise_Statement
;
1743 ----------------------------------
1744 -- Expand_N_Raise_Storage_Error --
1745 ----------------------------------
1747 procedure Expand_N_Raise_Storage_Error
(N
: Node_Id
) is
1749 -- We adjust the condition to deal with the C/Fortran boolean case. This
1750 -- may well not be necessary, as all such conditions are generated by
1751 -- the expander and probably are all standard boolean, but who knows
1752 -- what strange optimization in future may require this adjustment!
1754 Adjust_Condition
(Condition
(N
));
1756 -- Now deal with possible local raise handling
1758 Possible_Local_Raise
(N
, Standard_Storage_Error
);
1759 end Expand_N_Raise_Storage_Error
;
1761 --------------------------
1762 -- Possible_Local_Raise --
1763 --------------------------
1765 procedure Possible_Local_Raise
(N
: Node_Id
; E
: Entity_Id
) is
1767 -- Nothing to do if local raise optimization not active
1769 if not Debug_Flag_Dot_G
1770 and then not Restriction_Active
(No_Exception_Propagation
)
1775 -- Nothing to do if original node was an explicit raise, because in
1776 -- that case, we already generated the required warning for the raise.
1778 if Nkind
(Original_Node
(N
)) = N_Raise_Statement
then
1782 -- Otherwise see if we have a local handler for the exception
1785 H
: constant Node_Id
:= Find_Local_Handler
(E
, N
);
1788 -- If so, mark that it has a local raise
1791 Set_Has_Local_Raise
(H
, True);
1793 -- Otherwise, if the No_Exception_Propagation restriction is active
1794 -- and the warning is enabled, generate the appropriate warnings.
1796 elsif Warn_On_Non_Local_Exception
1797 and then Restriction_Active
(No_Exception_Propagation
)
1799 Warn_No_Exception_Propagation_Active
(N
);
1801 if Configurable_Run_Time_Mode
then
1803 ("\?& may call Last_Chance_Handler", N
, E
);
1806 ("\?& may result in unhandled exception", N
, E
);
1810 end Possible_Local_Raise
;
1812 ------------------------------
1813 -- Expand_N_Subprogram_Info --
1814 ------------------------------
1816 procedure Expand_N_Subprogram_Info
(N
: Node_Id
) is
1817 Loc
: constant Source_Ptr
:= Sloc
(N
);
1820 -- For now, we replace an Expand_N_Subprogram_Info node with an
1821 -- attribute reference that gives the address of the procedure.
1822 -- This is because gigi does not yet recognize this node, and
1823 -- for the initial targets, this is the right value anyway.
1826 Make_Attribute_Reference
(Loc
,
1827 Prefix
=> Identifier
(N
),
1828 Attribute_Name
=> Name_Code_Address
));
1830 Analyze_And_Resolve
(N
, RTE
(RE_Code_Loc
));
1831 end Expand_N_Subprogram_Info
;
1833 ------------------------
1834 -- Find_Local_Handler --
1835 ------------------------
1837 function Find_Local_Handler
1839 Nod
: Node_Id
) return Node_Id
1846 SSE
: Scope_Stack_Entry
renames Scope_Stack
.Table
(Scope_Stack
.Last
);
1847 -- This is used to test for wrapped actions below
1850 EHandle
: Entity_Id
;
1851 -- The entity Id's for the exception we are raising and handling, using
1852 -- the renamed exception if a Renamed_Entity is present.
1855 -- Never any local handler if all handlers removed
1857 if Debug_Flag_Dot_X
then
1861 -- Get the exception we are raising, allowing for renaming
1863 ERaise
:= Get_Renamed_Entity
(Ename
);
1865 -- We need to check if the node we are looking at is contained in
1868 -- Loop to search up the tree
1874 -- If we get to the top of the tree, or to a subprogram, task, entry,
1875 -- protected body, or accept statement without having found a
1876 -- matching handler, then there is no local handler.
1879 or else Nkind
(P
) = N_Subprogram_Body
1880 or else Nkind
(P
) = N_Task_Body
1881 or else Nkind
(P
) = N_Protected_Body
1882 or else Nkind
(P
) = N_Entry_Body
1883 or else Nkind
(P
) = N_Accept_Statement
1887 -- Test for handled sequence of statements with at least one
1888 -- exception handler which might be the one we are looking for.
1890 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
1891 and then Present
(Exception_Handlers
(P
))
1893 -- Before we proceed we need to check if the node N is covered
1894 -- by the statement part of P rather than one of its exception
1895 -- handlers (an exception handler obviously does not cover its
1898 -- This test is more delicate than might be thought. It is not
1899 -- just a matter of checking the Statements (P), because the node
1900 -- might be waiting to be wrapped in a transient scope, in which
1901 -- case it will end up in the block statements, even though it
1902 -- is not there now.
1904 if Is_List_Member
(N
)
1905 and then (List_Containing
(N
) = Statements
(P
)
1907 List_Containing
(N
) = SSE
.Actions_To_Be_Wrapped_Before
1909 List_Containing
(N
) = SSE
.Actions_To_Be_Wrapped_After
)
1911 -- Loop through exception handlers
1913 H
:= First
(Exception_Handlers
(P
));
1914 while Present
(H
) loop
1916 -- Loop through choices in one handler
1918 C
:= First
(Exception_Choices
(H
));
1919 while Present
(C
) loop
1921 -- Deal with others case
1923 if Nkind
(C
) = N_Others_Choice
then
1925 -- Matching others handler, but we need to ensure
1926 -- there is no choice parameter. If there is, then we
1927 -- don't have a local handler after all (since we do
1928 -- not allow choice parameters for local handlers).
1930 if No
(Choice_Parameter
(H
)) then
1936 -- If not others must be entity name
1938 elsif Nkind
(C
) /= N_Others_Choice
then
1939 pragma Assert
(Is_Entity_Name
(C
));
1940 pragma Assert
(Present
(Entity
(C
)));
1942 -- Get exception being handled, dealing with renaming
1944 EHandle
:= Get_Renamed_Entity
(Entity
(C
));
1946 -- If match, then check choice parameter
1948 if ERaise
= EHandle
then
1949 if No
(Choice_Parameter
(H
)) then
1967 end Find_Local_Handler
;
1969 ---------------------------------
1970 -- Get_Local_Raise_Call_Entity --
1971 ---------------------------------
1973 -- Note: this is primary provided for use by the back end in generating
1974 -- calls to Local_Raise. But it would be too late in the back end to call
1975 -- RTE if this actually caused a load/analyze of the unit. So what we do
1976 -- is to ensure there is a dummy call to this function during front end
1977 -- processing so that the unit gets loaded then, and not later.
1979 Local_Raise_Call_Entity
: Entity_Id
;
1980 Local_Raise_Call_Entity_Set
: Boolean := False;
1982 function Get_Local_Raise_Call_Entity
return Entity_Id
is
1984 if not Local_Raise_Call_Entity_Set
then
1985 Local_Raise_Call_Entity_Set
:= True;
1987 if RTE_Available
(RE_Local_Raise
) then
1988 Local_Raise_Call_Entity
:= RTE
(RE_Local_Raise
);
1990 Local_Raise_Call_Entity
:= Empty
;
1994 return Local_Raise_Call_Entity
;
1995 end Get_Local_Raise_Call_Entity
;
1997 -----------------------------
1998 -- Get_RT_Exception_Entity --
1999 -----------------------------
2001 function Get_RT_Exception_Entity
(R
: RT_Exception_Code
) return Entity_Id
is
2004 when RT_CE_Exceptions
=> return Standard_Constraint_Error
;
2005 when RT_PE_Exceptions
=> return Standard_Program_Error
;
2006 when RT_SE_Exceptions
=> return Standard_Storage_Error
;
2008 end Get_RT_Exception_Entity
;
2010 ----------------------
2011 -- Is_Non_Ada_Error --
2012 ----------------------
2014 function Is_Non_Ada_Error
(E
: Entity_Id
) return Boolean is
2016 if not OpenVMS_On_Target
then
2020 Get_Name_String
(Chars
(E
));
2022 -- Note: it is a little irregular for the body of exp_ch11 to know
2023 -- the details of the encoding scheme for names, but on the other
2024 -- hand, gigi knows them, and this is for gigi's benefit anyway!
2026 if Name_Buffer
(1 .. 30) /= "system__aux_dec__non_ada_error" then
2031 end Is_Non_Ada_Error
;
2033 ----------------------------
2034 -- Warn_If_No_Propagation --
2035 ----------------------------
2037 procedure Warn_If_No_Propagation
(N
: Node_Id
) is
2039 if Restriction_Check_Required
(No_Exception_Propagation
)
2040 and then Warn_On_Non_Local_Exception
2042 Warn_No_Exception_Propagation_Active
(N
);
2044 if Configurable_Run_Time_Mode
then
2046 ("\?Last_Chance_Handler will be called on exception", N
);
2049 ("\?execution may raise unhandled exception", N
);
2052 end Warn_If_No_Propagation
;
2054 ------------------------------------------
2055 -- Warn_No_Exception_Propagation_Active --
2056 ------------------------------------------
2058 procedure Warn_No_Exception_Propagation_Active
(N
: Node_Id
) is
2061 ("?pragma Restrictions (No_Exception_Propagation) in effect", N
);
2062 end Warn_No_Exception_Propagation_Active
;