1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, 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
:= Make_Temporary
(Sloc
(H
), 'L');
474 Set_Exception_Label
(H
, L
);
475 Add_Label_Declaration
(L
);
478 end Add_Exception_Label
;
480 ---------------------------
481 -- Add_Label_Declaration --
482 ---------------------------
484 procedure Add_Label_Declaration
(L
: Entity_Id
) is
485 P
: constant Node_Id
:= Parent
(HSS
);
487 Decl_L
: constant Node_Id
:=
488 Make_Implicit_Label_Declaration
(Loc
,
489 Defining_Identifier
=> L
);
492 if Declarations
(P
) = No_List
then
493 Set_Declarations
(P
, Empty_List
);
496 Append
(Decl_L
, Declarations
(P
));
498 end Add_Label_Declaration
;
500 -----------------------
501 -- Generate_Push_Pop --
502 -----------------------
504 procedure Generate_Push_Pop
(H
: Node_Id
) is
506 if Exc_Locally_Handled
then
509 Exc_Locally_Handled
:= True;
512 Add_Exception_Label
(H
);
515 F
: constant Node_Id
:= First
(Statements
(HSS
));
516 L
: constant Node_Id
:= Last
(Statements
(HSS
));
518 Push
: constant Node_Id
:= Make_Push_Label
(Sloc
(F
));
519 Pop
: constant Node_Id
:= Make_Pop_Label
(Sloc
(L
));
522 -- We make sure that a call to Get_Local_Raise_Call_Entity is
523 -- made during front end processing, so that when we need it
524 -- in the back end, it will already be available and loaded.
526 Discard_Node
(Get_Local_Raise_Call_Entity
);
528 -- Prepare and insert Push and Pop nodes
530 Set_Exception_Label
(Push
, Exception_Label
(H
));
531 Insert_Before
(F
, Push
);
534 Insert_After
(L
, Pop
);
537 end Generate_Push_Pop
;
539 -- Local declarations
541 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
542 Stmts
: List_Id
:= No_List
;
546 procedure Generate_Push_Pop_For_Constraint_Error
is
547 new Generate_Push_Pop
548 (Exc_Locally_Handled
=> CE_Locally_Handled
,
549 Make_Push_Label
=> Make_Push_Constraint_Error_Label
,
550 Make_Pop_Label
=> Make_Pop_Constraint_Error_Label
);
551 -- If no Push/Pop has been generated for CE yet, then set the flag
552 -- CE_Locally_Handled, allocate an Exception_Label for handler H (if
553 -- not already done), and generate Push/Pop nodes for the exception
554 -- label at the start and end of the statements of HSS.
556 procedure Generate_Push_Pop_For_Program_Error
is
557 new Generate_Push_Pop
558 (Exc_Locally_Handled
=> PE_Locally_Handled
,
559 Make_Push_Label
=> Make_Push_Program_Error_Label
,
560 Make_Pop_Label
=> Make_Pop_Program_Error_Label
);
561 -- If no Push/Pop has been generated for PE yet, then set the flag
562 -- PE_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_Storage_Error
is
567 new Generate_Push_Pop
568 (Exc_Locally_Handled
=> SE_Locally_Handled
,
569 Make_Push_Label
=> Make_Push_Storage_Error_Label
,
570 Make_Pop_Label
=> Make_Pop_Storage_Error_Label
);
571 -- If no Push/Pop has been generated for SE yet, then set the flag
572 -- SE_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 -- Start of processing for Expand_Local_Exception_Handlers
579 -- No processing if all exception handlers will get removed
581 if Debug_Flag_Dot_X
then
585 -- See for each handler if we have any local raises to expand
587 Handler
:= First_Non_Pragma
(Handlrs
);
588 while Present
(Handler
) loop
590 -- Note, we do not test Local_Raise_Not_OK here, because in the
591 -- case of Push/Pop generation we want to generate push with a
592 -- null label. The Add_Exception_Label routine has no effect if
593 -- Local_Raise_Not_OK is set, so this works as required.
595 if Present
(Local_Raise_Statements
(Handler
)) then
596 Add_Exception_Label
(Handler
);
599 -- If we are doing local raise to goto optimization (restriction
600 -- No_Exception_Propagation set or debug flag .g set), then check
601 -- to see if handler handles CE, PE, SE and if so generate the
602 -- appropriate push/pop sequence for the back end.
605 or else Restriction_Active
(No_Exception_Propagation
))
606 and then Has_Local_Raise
(Handler
)
608 Choice
:= First
(Exception_Choices
(Handler
));
609 while Present
(Choice
) loop
610 if Nkind
(Choice
) = N_Others_Choice
611 and then not All_Others
(Choice
)
613 Generate_Push_Pop_For_Constraint_Error
(Handler
);
614 Generate_Push_Pop_For_Program_Error
(Handler
);
615 Generate_Push_Pop_For_Storage_Error
(Handler
);
617 elsif Is_Entity_Name
(Choice
) then
618 Excep
:= Get_Renamed_Entity
(Entity
(Choice
));
620 if Excep
= Standard_Constraint_Error
then
621 Generate_Push_Pop_For_Constraint_Error
(Handler
);
622 elsif Excep
= Standard_Program_Error
then
623 Generate_Push_Pop_For_Program_Error
(Handler
);
624 elsif Excep
= Standard_Storage_Error
then
625 Generate_Push_Pop_For_Storage_Error
(Handler
);
633 Next_Non_Pragma
(Handler
);
636 -- Nothing to do if no handlers requiring the goto transformation
638 if not (Local_Expansion_Required
) then
642 -- Prepare to do the transformation
645 -- L3 is the label to exit the HSS
647 L3_Dent
: constant Entity_Id
:= Make_Temporary
(Loc
, 'L');
649 Labl_L3
: constant Node_Id
:=
651 Identifier
=> New_Occurrence_Of
(L3_Dent
, Loc
));
657 Set_Exception_Junk
(Labl_L3
);
658 Add_Label_Declaration
(L3_Dent
);
660 -- Wrap existing statements and handlers in an inner block
663 Make_Block_Statement
(Loc
,
664 Handled_Statement_Sequence
=> Relocate_Node
(HSS
));
665 Set_Exception_Junk
(Blk_Stm
);
668 Make_Handled_Sequence_Of_Statements
(Loc
,
669 Statements
=> New_List
(Blk_Stm
),
670 End_Label
=> Relocate_Node
(End_Label
(HSS
))));
672 -- Set block statement as analyzed, we don't want to actually call
673 -- Analyze on this block, it would cause a recursion in exception
674 -- handler processing which would mess things up.
676 Set_Analyzed
(Blk_Stm
);
678 -- Now loop through the exception handlers to deal with those that
679 -- are targets of local raise statements.
681 Handler
:= First_Non_Pragma
(Handlrs
);
682 while Present
(Handler
) loop
683 if Present
(Exception_Label
(Handler
)) then
685 -- This handler needs the goto expansion
688 Loc
: constant Source_Ptr
:= Sloc
(Handler
);
690 -- L1 is the start label for this handler
692 L1_Dent
: constant Entity_Id
:= Exception_Label
(Handler
);
694 Labl_L1
: constant Node_Id
:=
697 New_Occurrence_Of
(L1_Dent
, Loc
));
699 -- Jump to L1 to be used as replacement for the original
700 -- handler (used in the case where exception propagation
703 Name_L1
: constant Node_Id
:=
704 New_Occurrence_Of
(L1_Dent
, Loc
);
706 Goto_L1
: constant Node_Id
:=
707 Make_Goto_Statement
(Loc
,
710 -- Jump to L3 to be used at the end of handler
712 Name_L3
: constant Node_Id
:=
713 New_Occurrence_Of
(L3_Dent
, Loc
);
715 Goto_L3
: constant Node_Id
:=
716 Make_Goto_Statement
(Loc
,
719 H_Stmts
: constant List_Id
:= Statements
(Handler
);
722 Set_Exception_Junk
(Labl_L1
);
723 Set_Exception_Junk
(Goto_L3
);
725 -- Note: we do NOT set Exception_Junk in Goto_L1, since
726 -- this is a real transfer of control that we want the
727 -- Sem_Ch6.Check_Returns procedure to recognize properly.
729 -- Replace handler by a goto L1. We can mark this as
730 -- analyzed since it is fully formed, and we don't
731 -- want it going through any further checks. We save
732 -- the last statement location in the goto L1 node for
733 -- the benefit of Sem_Ch6.Check_Returns.
735 Set_Statements
(Handler
, New_List
(Goto_L1
));
736 Set_Analyzed
(Goto_L1
);
737 Set_Etype
(Name_L1
, Standard_Void_Type
);
739 -- Now replace all the raise statements by goto L1
741 if Present
(Local_Raise_Statements
(Handler
)) then
742 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
743 while Present
(Relmt
) loop
745 Raise_S
: constant Node_Id
:= Node
(Relmt
);
746 RLoc
: constant Source_Ptr
:= Sloc
(Raise_S
);
747 Name_L1
: constant Node_Id
:=
748 New_Occurrence_Of
(L1_Dent
, Loc
);
749 Goto_L1
: constant Node_Id
:=
750 Make_Goto_Statement
(RLoc
,
754 -- Replace raise by goto L1
756 Set_Analyzed
(Goto_L1
);
757 Set_Etype
(Name_L1
, Standard_Void_Type
);
758 Replace_Raise_By_Goto
(Raise_S
, Goto_L1
);
765 -- Add a goto L3 at end of statement list in block. The
766 -- first time, this is what skips over the exception
767 -- handlers in the normal case. Subsequent times, it
768 -- terminates the execution of the previous handler code,
769 -- and skips subsequent handlers.
771 Stmts
:= Statements
(HSS
);
773 Insert_After
(Last
(Stmts
), Goto_L3
);
774 Set_Analyzed
(Goto_L3
);
775 Set_Etype
(Name_L3
, Standard_Void_Type
);
777 -- Now we drop the label that marks the handler start,
778 -- followed by the statements of the handler.
780 Set_Etype
(Identifier
(Labl_L1
), Standard_Void_Type
);
782 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L1
);
785 Loc
: constant Source_Ptr
:= Sloc
(First
(H_Stmts
));
786 Blk
: constant Node_Id
:=
787 Make_Block_Statement
(Loc
,
788 Handled_Statement_Sequence
=>
789 Make_Handled_Sequence_Of_Statements
(Loc
,
790 Statements
=> H_Stmts
));
792 Set_Exception_Junk
(Blk
);
793 Insert_After_And_Analyze
(Last
(Stmts
), Blk
);
797 -- Here if we have local raise statements but the handler is
798 -- not suitable for processing with a local raise. In this
799 -- case we have to generate possible diagnostics.
801 elsif Has_Local_Raise
(Handler
)
802 and then Local_Raise_Statements
(Handler
) /= No_Elist
804 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
805 while Present
(Relmt
) loop
806 Warn_If_No_Propagation
(Node
(Relmt
));
814 -- Only remaining step is to drop the L3 label and we are done
816 Set_Etype
(Identifier
(Labl_L3
), Standard_Void_Type
);
818 -- If we had at least one handler, then we drop the label after
819 -- the last statement of that handler.
821 if Stmts
/= No_List
then
822 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L3
);
824 -- Otherwise we have removed all the handlers (this results from
825 -- use of pragma Restrictions (No_Exception_Propagation), and we
826 -- drop the label at the end of the statements of the HSS.
829 Insert_After_And_Analyze
(Last
(Statements
(HSS
)), Labl_L3
);
834 end Expand_Local_Exception_Handlers
;
836 -----------------------------
837 -- Prepend_Call_To_Handler --
838 -----------------------------
840 procedure Prepend_Call_To_Handler
842 Args
: List_Id
:= No_List
)
844 Ent
: constant Entity_Id
:= RTE
(Proc
);
847 -- If we have no Entity, then we are probably in no run time mode or
848 -- some weird error has occurred. In either case do nothing. Note use
849 -- of No_Location to hide this code from the debugger, so single
850 -- stepping doesn't jump back and forth.
852 if Present
(Ent
) then
854 Call
: constant Node_Id
:=
855 Make_Procedure_Call_Statement
(No_Location
,
856 Name
=> New_Occurrence_Of
(RTE
(Proc
), No_Location
),
857 Parameter_Associations
=> Args
);
860 Prepend_To
(Statements
(Handler
), Call
);
861 Analyze
(Call
, Suppress
=> All_Checks
);
864 end Prepend_Call_To_Handler
;
866 ---------------------------
867 -- Replace_Raise_By_Goto --
868 ---------------------------
870 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
) is
871 Loc
: constant Source_Ptr
:= Sloc
(Raise_S
);
878 -- If we have a null statement, it means that there is no replacement
879 -- needed (typically this results from a suppressed check).
881 if Nkind
(Raise_S
) = N_Null_Statement
then
884 -- Test for Raise_xxx_Error
886 elsif Nkind
(Raise_S
) = N_Raise_Constraint_Error
then
887 Excep
:= Standard_Constraint_Error
;
888 Cond
:= Condition
(Raise_S
);
890 elsif Nkind
(Raise_S
) = N_Raise_Storage_Error
then
891 Excep
:= Standard_Storage_Error
;
892 Cond
:= Condition
(Raise_S
);
894 elsif Nkind
(Raise_S
) = N_Raise_Program_Error
then
895 Excep
:= Standard_Program_Error
;
896 Cond
:= Condition
(Raise_S
);
898 -- The only other possibility is a node that is or used to be a
899 -- simple raise statement.
902 Orig
:= Original_Node
(Raise_S
);
903 pragma Assert
(Nkind
(Orig
) = N_Raise_Statement
904 and then Present
(Name
(Orig
))
905 and then No
(Expression
(Orig
)));
906 Excep
:= Entity
(Name
(Orig
));
910 -- Here Excep is the exception to raise, and Cond is the condition
911 -- First prepare the call to Local_Raise (excep'address).
913 if RTE_Available
(RE_Local_Raise
) then
915 Make_Procedure_Call_Statement
(Loc
,
916 Name
=> New_Occurrence_Of
(RTE
(RE_Local_Raise
), Loc
),
917 Parameter_Associations
=> New_List
(
918 Unchecked_Convert_To
(RTE
(RE_Address
),
919 Make_Attribute_Reference
(Loc
,
920 Prefix
=> New_Occurrence_Of
(Excep
, Loc
),
921 Attribute_Name
=> Name_Identity
))));
923 -- Use null statement if Local_Raise not available
927 Make_Null_Statement
(Loc
);
930 -- If there is no condition, we rewrite as
933 -- Local_Raise (excep'Identity);
939 Make_Block_Statement
(Loc
,
940 Handled_Statement_Sequence
=>
941 Make_Handled_Sequence_Of_Statements
(Loc
,
942 Statements
=> New_List
(LR
, Goto_L1
))));
943 Set_Exception_Junk
(Raise_S
);
945 -- If there is a condition, we rewrite as
948 -- Local_Raise (excep'Identity);
954 Make_If_Statement
(Loc
,
956 Then_Statements
=> New_List
(LR
, Goto_L1
)));
960 end Replace_Raise_By_Goto
;
962 -- Start of processing for Expand_Exception_Handlers
965 Expand_Local_Exception_Handlers
;
967 -- Loop through handlers
969 Handler
:= First_Non_Pragma
(Handlrs
);
970 Handler_Loop
: while Present
(Handler
) loop
971 Next_Handler
:= Next_Non_Pragma
(Handler
);
973 -- Remove source handler if gnat debug flag .x is set
975 if Debug_Flag_Dot_X
and then Comes_From_Source
(Handler
) then
978 -- Remove handler if no exception propagation, generating a warning
979 -- if a source generated handler was not the target of a local raise.
982 if Restriction_Active
(No_Exception_Propagation
)
983 and then not Has_Local_Raise
(Handler
)
984 and then Comes_From_Source
(Handler
)
985 and then Warn_On_Non_Local_Exception
987 Warn_No_Exception_Propagation_Active
(Handler
);
989 ("\?this handler can never be entered, and has been removed",
993 if No_Exception_Propagation_Active
then
996 -- Exception handler is active and retained and must be processed
999 -- If an exception occurrence is present, then we must declare
1000 -- it and initialize it from the value stored in the TSD
1003 -- name : Exception_Occurrence;
1005 -- Save_Occurrence (name, Get_Current_Excep.all)
1009 if Present
(Choice_Parameter
(Handler
)) then
1011 Cparm
: constant Entity_Id
:= Choice_Parameter
(Handler
);
1012 Cloc
: constant Source_Ptr
:= Sloc
(Cparm
);
1013 Hloc
: constant Source_Ptr
:= Sloc
(Handler
);
1017 -- Note use of No_Location to hide this code from the
1018 -- debugger, so single stepping doesn't jump back and
1022 Make_Procedure_Call_Statement
(No_Location
,
1024 New_Occurrence_Of
(RTE
(RE_Save_Occurrence
),
1026 Parameter_Associations
=> New_List
(
1027 New_Occurrence_Of
(Cparm
, Cloc
),
1028 Make_Explicit_Dereference
(No_Location
,
1029 Make_Function_Call
(No_Location
,
1030 Name
=> Make_Explicit_Dereference
(No_Location
,
1032 (RTE
(RE_Get_Current_Excep
),
1035 Mark_Rewrite_Insertion
(Save
);
1036 Prepend
(Save
, Statements
(Handler
));
1039 Make_Object_Declaration
1041 Defining_Identifier
=> Cparm
,
1042 Object_Definition
=>
1044 (RTE
(RE_Exception_Occurrence
), Cloc
));
1045 Set_No_Initialization
(Obj_Decl
, True);
1048 Make_Exception_Handler
(Hloc
,
1049 Choice_Parameter
=> Empty
,
1050 Exception_Choices
=> Exception_Choices
(Handler
),
1052 Statements
=> New_List
(
1053 Make_Block_Statement
(Hloc
,
1054 Declarations
=> New_List
(Obj_Decl
),
1055 Handled_Statement_Sequence
=>
1056 Make_Handled_Sequence_Of_Statements
(Hloc
,
1057 Statements
=> Statements
(Handler
))))));
1059 -- Local raise statements can't occur, since exception
1060 -- handlers with choice parameters are not allowed when
1061 -- No_Exception_Propagation applies, so set attributes
1064 Set_Local_Raise_Statements
(Handler
, No_Elist
);
1065 Set_Local_Raise_Not_OK
(Handler
);
1068 (Statements
(Handler
), Suppress
=> All_Checks
);
1072 -- The processing at this point is rather different for the JVM
1073 -- case, so we completely separate the processing.
1075 -- For the VM case, we unconditionally call Update_Exception,
1076 -- passing a call to the intrinsic Current_Target_Exception
1077 -- (see JVM/.NET versions of Ada.Exceptions for details).
1079 if VM_Target
/= No_VM
then
1081 Arg
: constant Node_Id
:=
1082 Make_Function_Call
(Loc
,
1085 (RTE
(RE_Current_Target_Exception
), Loc
));
1087 Prepend_Call_To_Handler
1088 (RE_Update_Exception
, New_List
(Arg
));
1091 -- For the normal case, we have to worry about the state of
1092 -- abort deferral. Generally, we defer abort during runtime
1093 -- handling of exceptions. When control is passed to the
1094 -- handler, then in the normal case we undefer aborts. In
1095 -- any case this entire handling is relevant only if aborts
1098 elsif Abort_Allowed
then
1100 -- There are some special cases in which we do not do the
1101 -- undefer. In particular a finalization (AT END) handler
1102 -- wants to operate with aborts still deferred.
1104 -- We also suppress the call if this is the special handler
1105 -- for Abort_Signal, since if we are aborting, we want to
1106 -- keep aborts deferred (one abort is enough).
1108 -- If abort really needs to be deferred the expander must
1109 -- add this call explicitly, see
1110 -- Expand_N_Asynchronous_Select.
1113 Nkind
(First
(Exception_Choices
(Handler
))) =
1117 or else Entity
(First
(Exception_Choices
(Handler
))) /=
1122 All_Others
(First
(Exception_Choices
(Handler
))))
1123 and then Abort_Allowed
1125 Prepend_Call_To_Handler
(RE_Abort_Undefer
);
1131 Handler
:= Next_Handler
;
1132 end loop Handler_Loop
;
1134 -- If all handlers got removed, then remove the list. Note we cannot
1135 -- reference HSS here, since expanding local handlers may have buried
1136 -- the handlers in an inner block.
1138 if Is_Empty_List
(Handlrs
) then
1139 Set_Exception_Handlers
(Parent
(Handlrs
), No_List
);
1141 end Expand_Exception_Handlers
;
1143 ------------------------------------
1144 -- Expand_N_Exception_Declaration --
1145 ------------------------------------
1148 -- exceptE : constant String := "A.B.EXCEP"; -- static data
1149 -- except : exception_data := (
1150 -- Handled_By_Other => False,
1152 -- Name_Length => exceptE'Length,
1153 -- Full_Name => exceptE'Address,
1154 -- HTable_Ptr => null,
1155 -- Import_Code => 0,
1156 -- Raise_Hook => null,
1159 -- (protecting test only needed if not at library level)
1161 -- exceptF : Boolean := True -- static data
1163 -- exceptF := False;
1164 -- Register_Exception (except'Unchecked_Access);
1167 procedure Expand_N_Exception_Declaration
(N
: Node_Id
) is
1168 Loc
: constant Source_Ptr
:= Sloc
(N
);
1169 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
1170 L
: List_Id
:= New_List
;
1171 Flag_Id
: Entity_Id
;
1173 Name_Exname
: constant Name_Id
:= New_External_Name
(Chars
(Id
), 'E');
1174 Exname
: constant Node_Id
:=
1175 Make_Defining_Identifier
(Loc
, Name_Exname
);
1177 procedure Force_Static_Allocation_Of_Referenced_Objects
1178 (Aggregate
: Node_Id
);
1179 -- A specialized solution to one particular case of an ugly problem
1181 -- The given aggregate includes an Unchecked_Conversion as one of the
1182 -- component values. The call to Analyze_And_Resolve below ends up
1183 -- calling Exp_Ch4.Expand_N_Unchecked_Type_Conversion, which may decide
1184 -- to introduce a (constant) temporary and then obtain the component
1185 -- value by evaluating the temporary.
1187 -- In the case of an exception declared within a subprogram (or any
1188 -- other dynamic scope), this is a bad transformation. The exception
1189 -- object is marked as being Statically_Allocated but the temporary is
1190 -- not. If the initial value of a Statically_Allocated declaration
1191 -- references a dynamically allocated object, this prevents static
1192 -- initialization of the object.
1194 -- We cope with this here by marking the temporary Statically_Allocated.
1195 -- It might seem cleaner to generalize this utility and then use it to
1196 -- enforce a rule that the entities referenced in the declaration of any
1197 -- "hoisted" (i.e., Is_Statically_Allocated and not Is_Library_Level)
1198 -- entity must also be either Library_Level or hoisted. It turns out
1199 -- that this would be incompatible with the current treatment of an
1200 -- object which is local to a subprogram, subject to an Export pragma,
1201 -- not subject to an address clause, and whose declaration contains
1202 -- references to other local (non-hoisted) objects (e.g., in the initial
1203 -- value expression).
1205 ---------------------------------------------------
1206 -- Force_Static_Allocation_Of_Referenced_Objects --
1207 ---------------------------------------------------
1209 procedure Force_Static_Allocation_Of_Referenced_Objects
1210 (Aggregate
: Node_Id
)
1212 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
;
1213 -- If the given node references a dynamically allocated object, then
1214 -- correct the declaration of the object.
1220 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
is
1222 if Nkind
(N
) in N_Has_Entity
1223 and then Present
(Entity
(N
))
1224 and then not Is_Library_Level_Entity
(Entity
(N
))
1226 -- Note: the following test is not needed but it seems cleaner
1227 -- to do this test (this would be more important if procedure
1228 -- Force_Static_Allocation_Of_Referenced_Objects recursively
1229 -- traversed the declaration of an entity after marking it as
1230 -- statically allocated).
1232 and then not Is_Statically_Allocated
(Entity
(N
))
1234 Set_Is_Statically_Allocated
(Entity
(N
));
1240 procedure Fixup_Tree
is new Traverse_Proc
(Fixup_Node
);
1242 -- Start of processing for Force_Static_Allocation_Of_Referenced_Objects
1245 Fixup_Tree
(Aggregate
);
1246 end Force_Static_Allocation_Of_Referenced_Objects
;
1248 -- Start of processing for Expand_N_Exception_Declaration
1251 -- There is no expansion needed when compiling for the JVM since the
1252 -- JVM has a built-in exception mechanism. See 4jexcept.ads for details.
1254 if VM_Target
/= No_VM
then
1258 -- Definition of the external name: nam : constant String := "A.B.NAME";
1261 Make_Object_Declaration
(Loc
,
1262 Defining_Identifier
=> Exname
,
1263 Constant_Present
=> True,
1264 Object_Definition
=> New_Occurrence_Of
(Standard_String
, Loc
),
1266 Make_String_Literal
(Loc
,
1267 Strval
=> Full_Qualified_Name
(Id
))));
1269 Set_Is_Statically_Allocated
(Exname
);
1271 -- Create the aggregate list for type Standard.Exception_Type:
1272 -- Handled_By_Other component: False
1274 Append_To
(L
, New_Occurrence_Of
(Standard_False
, Loc
));
1276 -- Lang component: 'A'
1279 Make_Character_Literal
(Loc
,
1281 Char_Literal_Value
=> UI_From_Int
(Character'Pos ('A'))));
1283 -- Name_Length component: Nam'Length
1286 Make_Attribute_Reference
(Loc
,
1287 Prefix
=> New_Occurrence_Of
(Exname
, Loc
),
1288 Attribute_Name
=> Name_Length
));
1290 -- Full_Name component: Standard.A_Char!(Nam'Address)
1292 Append_To
(L
, Unchecked_Convert_To
(Standard_A_Char
,
1293 Make_Attribute_Reference
(Loc
,
1294 Prefix
=> New_Occurrence_Of
(Exname
, Loc
),
1295 Attribute_Name
=> Name_Address
)));
1297 -- HTable_Ptr component: null
1299 Append_To
(L
, Make_Null
(Loc
));
1301 -- Import_Code component: 0
1303 Append_To
(L
, Make_Integer_Literal
(Loc
, 0));
1305 -- Raise_Hook component: null
1307 Append_To
(L
, Make_Null
(Loc
));
1309 Set_Expression
(N
, Make_Aggregate
(Loc
, Expressions
=> L
));
1310 Analyze_And_Resolve
(Expression
(N
), Etype
(Id
));
1312 Force_Static_Allocation_Of_Referenced_Objects
(Expression
(N
));
1314 -- Register_Exception (except'Unchecked_Access);
1316 if not No_Exception_Handlers_Set
1317 and then not Restriction_Active
(No_Exception_Registration
)
1320 Make_Procedure_Call_Statement
(Loc
,
1321 Name
=> New_Occurrence_Of
(RTE
(RE_Register_Exception
), Loc
),
1322 Parameter_Associations
=> New_List
(
1323 Unchecked_Convert_To
(RTE
(RE_Exception_Data_Ptr
),
1324 Make_Attribute_Reference
(Loc
,
1325 Prefix
=> New_Occurrence_Of
(Id
, Loc
),
1326 Attribute_Name
=> Name_Unrestricted_Access
)))));
1328 Set_Register_Exception_Call
(Id
, First
(L
));
1330 if not Is_Library_Level_Entity
(Id
) then
1331 Flag_Id
:= Make_Defining_Identifier
(Loc
,
1332 New_External_Name
(Chars
(Id
), 'F'));
1335 Make_Object_Declaration
(Loc
,
1336 Defining_Identifier
=> Flag_Id
,
1337 Object_Definition
=>
1338 New_Occurrence_Of
(Standard_Boolean
, Loc
),
1340 New_Occurrence_Of
(Standard_True
, Loc
)));
1342 Set_Is_Statically_Allocated
(Flag_Id
);
1345 Make_Assignment_Statement
(Loc
,
1346 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1347 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
1349 Insert_After_And_Analyze
(N
,
1350 Make_Implicit_If_Statement
(N
,
1351 Condition
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1352 Then_Statements
=> L
));
1355 Insert_List_After_And_Analyze
(N
, L
);
1358 end Expand_N_Exception_Declaration
;
1360 ---------------------------------------------
1361 -- Expand_N_Handled_Sequence_Of_Statements --
1362 ---------------------------------------------
1364 procedure Expand_N_Handled_Sequence_Of_Statements
(N
: Node_Id
) is
1366 -- Expand exception handlers
1368 if Present
(Exception_Handlers
(N
))
1369 and then not Restriction_Active
(No_Exception_Handlers
)
1371 Expand_Exception_Handlers
(N
);
1374 -- If local exceptions are being expanded, the previous call will
1375 -- have rewritten the construct as a block and reanalyzed it. No
1376 -- further expansion is needed.
1378 if Analyzed
(N
) then
1382 -- Add clean up actions if required
1384 if Nkind
(Parent
(N
)) /= N_Package_Body
1385 and then Nkind
(Parent
(N
)) /= N_Accept_Statement
1386 and then Nkind
(Parent
(N
)) /= N_Extended_Return_Statement
1387 and then not Delay_Cleanups
(Current_Scope
)
1389 Expand_Cleanup_Actions
(Parent
(N
));
1391 Set_First_Real_Statement
(N
, First
(Statements
(N
)));
1393 end Expand_N_Handled_Sequence_Of_Statements
;
1395 -------------------------------------
1396 -- Expand_N_Raise_Constraint_Error --
1397 -------------------------------------
1399 procedure Expand_N_Raise_Constraint_Error
(N
: Node_Id
) is
1401 -- We adjust the condition to deal with the C/Fortran boolean case. This
1402 -- may well not be necessary, as all such conditions are generated by
1403 -- the expander and probably are all standard boolean, but who knows
1404 -- what strange optimization in future may require this adjustment!
1406 Adjust_Condition
(Condition
(N
));
1408 -- Now deal with possible local raise handling
1410 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
1411 end Expand_N_Raise_Constraint_Error
;
1413 ----------------------------------
1414 -- Expand_N_Raise_Program_Error --
1415 ----------------------------------
1417 procedure Expand_N_Raise_Program_Error
(N
: Node_Id
) is
1419 -- We adjust the condition to deal with the C/Fortran boolean case. This
1420 -- may well not be necessary, as all such conditions are generated by
1421 -- the expander and probably are all standard boolean, but who knows
1422 -- what strange optimization in future may require this adjustment!
1424 Adjust_Condition
(Condition
(N
));
1426 -- Now deal with possible local raise handling
1428 Possible_Local_Raise
(N
, Standard_Program_Error
);
1429 end Expand_N_Raise_Program_Error
;
1431 ------------------------------
1432 -- Expand_N_Raise_Statement --
1433 ------------------------------
1435 procedure Expand_N_Raise_Statement
(N
: Node_Id
) is
1436 Loc
: constant Source_Ptr
:= Sloc
(N
);
1443 -- Processing for locally handled exception (exclude reraise case)
1445 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1447 or else Restriction_Active
(No_Exception_Propagation
)
1449 -- If we have a local handler, then note that this is potentially
1450 -- able to be transformed into a goto statement.
1452 H
:= Find_Local_Handler
(Entity
(Name
(N
)), N
);
1455 if Local_Raise_Statements
(H
) = No_Elist
then
1456 Set_Local_Raise_Statements
(H
, New_Elmt_List
);
1459 -- Append the new entry if it is not there already. Sometimes
1460 -- we have situations where due to reexpansion, the same node
1461 -- is analyzed twice and would otherwise be added twice.
1463 Append_Unique_Elmt
(N
, Local_Raise_Statements
(H
));
1464 Set_Has_Local_Raise
(H
);
1466 -- If no local handler, then generate no propagation warning
1469 Warn_If_No_Propagation
(N
);
1475 -- If a string expression is present, then the raise statement is
1476 -- converted to a call:
1477 -- Raise_Exception (exception-name'Identity, string);
1478 -- and there is nothing else to do.
1480 if Present
(Expression
(N
)) then
1482 -- Avoid passing exception-name'identity in runtimes in which this
1483 -- argument is not used. This avoids generating undefined references
1484 -- to these exceptions when compiling with no optimization
1486 if Configurable_Run_Time_On_Target
1487 and then (Restriction_Active
(No_Exception_Handlers
)
1489 Restriction_Active
(No_Exception_Propagation
))
1492 Make_Procedure_Call_Statement
(Loc
,
1493 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1494 Parameter_Associations
=> New_List
(
1495 New_Occurrence_Of
(RTE
(RE_Null_Id
), Loc
),
1499 Make_Procedure_Call_Statement
(Loc
,
1500 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1501 Parameter_Associations
=> New_List
(
1502 Make_Attribute_Reference
(Loc
,
1504 Attribute_Name
=> Name_Identity
),
1512 -- Remaining processing is for the case where no string expression
1515 -- Don't expand a raise statement that does not come from source
1516 -- if we have already had configurable run-time violations, since
1517 -- most likely it will be junk cascaded nonsense.
1519 if Configurable_Run_Time_Violations
> 0
1520 and then not Comes_From_Source
(N
)
1525 -- Convert explicit raise of Program_Error, Constraint_Error, and
1526 -- Storage_Error into the corresponding raise (in High_Integrity_Mode
1527 -- all other raises will get normal expansion and be disallowed,
1528 -- but this is also faster in all modes).
1530 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1531 if Entity
(Name
(N
)) = Standard_Constraint_Error
then
1533 Make_Raise_Constraint_Error
(Loc
,
1534 Reason
=> CE_Explicit_Raise
));
1538 elsif Entity
(Name
(N
)) = Standard_Program_Error
then
1540 Make_Raise_Program_Error
(Loc
,
1541 Reason
=> PE_Explicit_Raise
));
1545 elsif Entity
(Name
(N
)) = Standard_Storage_Error
then
1547 Make_Raise_Storage_Error
(Loc
,
1548 Reason
=> SE_Explicit_Raise
));
1554 -- Case of name present, in this case we expand raise name to
1556 -- Raise_Exception (name'Identity, location_string);
1558 -- where location_string identifies the file/line of the raise
1560 if Present
(Name
(N
)) then
1562 Id
: Entity_Id
:= Entity
(Name
(N
));
1566 Build_Location_String
(Loc
);
1568 -- If the exception is a renaming, use the exception that it
1569 -- renames (which might be a predefined exception, e.g.).
1571 if Present
(Renamed_Object
(Id
)) then
1572 Id
:= Renamed_Object
(Id
);
1575 -- Build a C-compatible string in case of no exception handlers,
1576 -- since this is what the last chance handler is expecting.
1578 if No_Exception_Handlers_Set
then
1580 -- Generate an empty message if configuration pragma
1581 -- Suppress_Exception_Locations is set for this unit.
1583 if Opt
.Exception_Locations_Suppressed
then
1586 Name_Len
:= Name_Len
+ 1;
1589 Name_Buffer
(Name_Len
) := ASCII
.NUL
;
1592 if Opt
.Exception_Locations_Suppressed
then
1596 Str
:= String_From_Name_Buffer
;
1598 -- For VMS exceptions, convert the raise into a call to
1599 -- lib$stop so it will be handled by __gnat_error_handler.
1601 if Is_VMS_Exception
(Id
) then
1603 Excep_Image
: String_Id
;
1607 if Present
(Interface_Name
(Id
)) then
1608 Excep_Image
:= Strval
(Interface_Name
(Id
));
1610 Get_Name_String
(Chars
(Id
));
1612 Excep_Image
:= String_From_Name_Buffer
;
1615 if Exception_Code
(Id
) /= No_Uint
then
1617 Make_Integer_Literal
(Loc
, Exception_Code
(Id
));
1620 Unchecked_Convert_To
(Standard_Integer
,
1621 Make_Function_Call
(Loc
,
1622 Name
=> New_Occurrence_Of
1623 (RTE
(RE_Import_Value
), Loc
),
1624 Parameter_Associations
=> New_List
1625 (Make_String_Literal
(Loc
,
1626 Strval
=> Excep_Image
))));
1630 Make_Procedure_Call_Statement
(Loc
,
1632 New_Occurrence_Of
(RTE
(RE_Lib_Stop
), Loc
),
1633 Parameter_Associations
=> New_List
(Cond
)));
1634 Analyze_And_Resolve
(Cond
, Standard_Integer
);
1637 -- Not VMS exception case, convert raise to call to the
1638 -- Raise_Exception routine.
1642 Make_Procedure_Call_Statement
(Loc
,
1643 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1644 Parameter_Associations
=> New_List
(
1645 Make_Attribute_Reference
(Loc
,
1647 Attribute_Name
=> Name_Identity
),
1648 Make_String_Literal
(Loc
,
1653 -- Case of no name present (reraise). We rewrite the raise to:
1655 -- Reraise_Occurrence_Always (EO);
1657 -- where EO is the current exception occurrence. If the current handler
1658 -- does not have a choice parameter specification, then we provide one.
1661 -- Find innermost enclosing exception handler (there must be one,
1662 -- since the semantics has already verified that this raise statement
1663 -- is valid, and a raise with no arguments is only permitted in the
1664 -- context of an exception handler.
1666 Ehand
:= Parent
(N
);
1667 while Nkind
(Ehand
) /= N_Exception_Handler
loop
1668 Ehand
:= Parent
(Ehand
);
1671 -- Make exception choice parameter if none present. Note that we do
1672 -- not need to put the entity on the entity chain, since no one will
1673 -- be referencing this entity by normal visibility methods.
1675 if No
(Choice_Parameter
(Ehand
)) then
1676 E
:= Make_Temporary
(Loc
, 'E');
1677 Set_Choice_Parameter
(Ehand
, E
);
1678 Set_Ekind
(E
, E_Variable
);
1679 Set_Etype
(E
, RTE
(RE_Exception_Occurrence
));
1680 Set_Scope
(E
, Current_Scope
);
1683 -- Now rewrite the raise as a call to Reraise. A special case arises
1684 -- if this raise statement occurs in the context of a handler for
1685 -- all others (i.e. an at end handler). in this case we avoid
1686 -- the call to defer abort, cleanup routines are expected to be
1687 -- called in this case with aborts deferred.
1690 Ech
: constant Node_Id
:= First
(Exception_Choices
(Ehand
));
1694 if Nkind
(Ech
) = N_Others_Choice
1695 and then All_Others
(Ech
)
1697 Ent
:= RTE
(RE_Reraise_Occurrence_No_Defer
);
1699 Ent
:= RTE
(RE_Reraise_Occurrence_Always
);
1703 Make_Procedure_Call_Statement
(Loc
,
1704 Name
=> New_Occurrence_Of
(Ent
, Loc
),
1705 Parameter_Associations
=> New_List
(
1706 New_Occurrence_Of
(Choice_Parameter
(Ehand
), Loc
))));
1711 end Expand_N_Raise_Statement
;
1713 ----------------------------------
1714 -- Expand_N_Raise_Storage_Error --
1715 ----------------------------------
1717 procedure Expand_N_Raise_Storage_Error
(N
: Node_Id
) is
1719 -- We adjust the condition to deal with the C/Fortran boolean case. This
1720 -- may well not be necessary, as all such conditions are generated by
1721 -- the expander and probably are all standard boolean, but who knows
1722 -- what strange optimization in future may require this adjustment!
1724 Adjust_Condition
(Condition
(N
));
1726 -- Now deal with possible local raise handling
1728 Possible_Local_Raise
(N
, Standard_Storage_Error
);
1729 end Expand_N_Raise_Storage_Error
;
1731 --------------------------
1732 -- Possible_Local_Raise --
1733 --------------------------
1735 procedure Possible_Local_Raise
(N
: Node_Id
; E
: Entity_Id
) is
1737 -- Nothing to do if local raise optimization not active
1739 if not Debug_Flag_Dot_G
1740 and then not Restriction_Active
(No_Exception_Propagation
)
1745 -- Nothing to do if original node was an explicit raise, because in
1746 -- that case, we already generated the required warning for the raise.
1748 if Nkind
(Original_Node
(N
)) = N_Raise_Statement
then
1752 -- Otherwise see if we have a local handler for the exception
1755 H
: constant Node_Id
:= Find_Local_Handler
(E
, N
);
1758 -- If so, mark that it has a local raise
1761 Set_Has_Local_Raise
(H
, True);
1763 -- Otherwise, if the No_Exception_Propagation restriction is active
1764 -- and the warning is enabled, generate the appropriate warnings.
1766 elsif Warn_On_Non_Local_Exception
1767 and then Restriction_Active
(No_Exception_Propagation
)
1769 Warn_No_Exception_Propagation_Active
(N
);
1771 if Configurable_Run_Time_Mode
then
1773 ("\?& may call Last_Chance_Handler", N
, E
);
1776 ("\?& may result in unhandled exception", N
, E
);
1780 end Possible_Local_Raise
;
1782 ------------------------------
1783 -- Expand_N_Subprogram_Info --
1784 ------------------------------
1786 procedure Expand_N_Subprogram_Info
(N
: Node_Id
) is
1787 Loc
: constant Source_Ptr
:= Sloc
(N
);
1790 -- For now, we replace an Expand_N_Subprogram_Info node with an
1791 -- attribute reference that gives the address of the procedure.
1792 -- This is because gigi does not yet recognize this node, and
1793 -- for the initial targets, this is the right value anyway.
1796 Make_Attribute_Reference
(Loc
,
1797 Prefix
=> Identifier
(N
),
1798 Attribute_Name
=> Name_Code_Address
));
1800 Analyze_And_Resolve
(N
, RTE
(RE_Code_Loc
));
1801 end Expand_N_Subprogram_Info
;
1803 ------------------------
1804 -- Find_Local_Handler --
1805 ------------------------
1807 function Find_Local_Handler
1809 Nod
: Node_Id
) return Node_Id
1816 SSE
: Scope_Stack_Entry
renames Scope_Stack
.Table
(Scope_Stack
.Last
);
1817 -- This is used to test for wrapped actions below
1820 EHandle
: Entity_Id
;
1821 -- The entity Id's for the exception we are raising and handling, using
1822 -- the renamed exception if a Renamed_Entity is present.
1825 -- Never any local handler if all handlers removed
1827 if Debug_Flag_Dot_X
then
1831 -- Get the exception we are raising, allowing for renaming
1833 ERaise
:= Get_Renamed_Entity
(Ename
);
1835 -- We need to check if the node we are looking at is contained in
1838 -- Loop to search up the tree
1844 -- If we get to the top of the tree, or to a subprogram, task, entry,
1845 -- protected body, or accept statement without having found a
1846 -- matching handler, then there is no local handler.
1849 or else Nkind
(P
) = N_Subprogram_Body
1850 or else Nkind
(P
) = N_Task_Body
1851 or else Nkind
(P
) = N_Protected_Body
1852 or else Nkind
(P
) = N_Entry_Body
1853 or else Nkind
(P
) = N_Accept_Statement
1857 -- Test for handled sequence of statements with at least one
1858 -- exception handler which might be the one we are looking for.
1860 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
1861 and then Present
(Exception_Handlers
(P
))
1863 -- Before we proceed we need to check if the node N is covered
1864 -- by the statement part of P rather than one of its exception
1865 -- handlers (an exception handler obviously does not cover its
1868 -- This test is more delicate than might be thought. It is not
1869 -- just a matter of checking the Statements (P), because the node
1870 -- might be waiting to be wrapped in a transient scope, in which
1871 -- case it will end up in the block statements, even though it
1872 -- is not there now.
1874 if Is_List_Member
(N
)
1875 and then (List_Containing
(N
) = Statements
(P
)
1877 List_Containing
(N
) = SSE
.Actions_To_Be_Wrapped_Before
1879 List_Containing
(N
) = SSE
.Actions_To_Be_Wrapped_After
)
1881 -- Loop through exception handlers
1883 H
:= First
(Exception_Handlers
(P
));
1884 while Present
(H
) loop
1886 -- Loop through choices in one handler
1888 C
:= First
(Exception_Choices
(H
));
1889 while Present
(C
) loop
1891 -- Deal with others case
1893 if Nkind
(C
) = N_Others_Choice
then
1895 -- Matching others handler, but we need to ensure
1896 -- there is no choice parameter. If there is, then we
1897 -- don't have a local handler after all (since we do
1898 -- not allow choice parameters for local handlers).
1900 if No
(Choice_Parameter
(H
)) then
1906 -- If not others must be entity name
1908 elsif Nkind
(C
) /= N_Others_Choice
then
1909 pragma Assert
(Is_Entity_Name
(C
));
1910 pragma Assert
(Present
(Entity
(C
)));
1912 -- Get exception being handled, dealing with renaming
1914 EHandle
:= Get_Renamed_Entity
(Entity
(C
));
1916 -- If match, then check choice parameter
1918 if ERaise
= EHandle
then
1919 if No
(Choice_Parameter
(H
)) then
1937 end Find_Local_Handler
;
1939 ---------------------------------
1940 -- Get_Local_Raise_Call_Entity --
1941 ---------------------------------
1943 -- Note: this is primary provided for use by the back end in generating
1944 -- calls to Local_Raise. But it would be too late in the back end to call
1945 -- RTE if this actually caused a load/analyze of the unit. So what we do
1946 -- is to ensure there is a dummy call to this function during front end
1947 -- processing so that the unit gets loaded then, and not later.
1949 Local_Raise_Call_Entity
: Entity_Id
;
1950 Local_Raise_Call_Entity_Set
: Boolean := False;
1952 function Get_Local_Raise_Call_Entity
return Entity_Id
is
1954 if not Local_Raise_Call_Entity_Set
then
1955 Local_Raise_Call_Entity_Set
:= True;
1957 if RTE_Available
(RE_Local_Raise
) then
1958 Local_Raise_Call_Entity
:= RTE
(RE_Local_Raise
);
1960 Local_Raise_Call_Entity
:= Empty
;
1964 return Local_Raise_Call_Entity
;
1965 end Get_Local_Raise_Call_Entity
;
1967 -----------------------------
1968 -- Get_RT_Exception_Entity --
1969 -----------------------------
1971 function Get_RT_Exception_Entity
(R
: RT_Exception_Code
) return Entity_Id
is
1974 when RT_CE_Exceptions
=> return Standard_Constraint_Error
;
1975 when RT_PE_Exceptions
=> return Standard_Program_Error
;
1976 when RT_SE_Exceptions
=> return Standard_Storage_Error
;
1978 end Get_RT_Exception_Entity
;
1980 ----------------------
1981 -- Is_Non_Ada_Error --
1982 ----------------------
1984 function Is_Non_Ada_Error
(E
: Entity_Id
) return Boolean is
1986 if not OpenVMS_On_Target
then
1990 Get_Name_String
(Chars
(E
));
1992 -- Note: it is a little irregular for the body of exp_ch11 to know
1993 -- the details of the encoding scheme for names, but on the other
1994 -- hand, gigi knows them, and this is for gigi's benefit anyway!
1996 if Name_Buffer
(1 .. 30) /= "system__aux_dec__non_ada_error" then
2001 end Is_Non_Ada_Error
;
2003 ----------------------------
2004 -- Warn_If_No_Propagation --
2005 ----------------------------
2007 procedure Warn_If_No_Propagation
(N
: Node_Id
) is
2009 if Restriction_Active
(No_Exception_Propagation
)
2010 and then Warn_On_Non_Local_Exception
2012 Warn_No_Exception_Propagation_Active
(N
);
2014 if Configurable_Run_Time_Mode
then
2016 ("\?Last_Chance_Handler will be called on exception", N
);
2019 ("\?execution may raise unhandled exception", N
);
2022 end Warn_If_No_Propagation
;
2024 ------------------------------------------
2025 -- Warn_No_Exception_Propagation_Active --
2026 ------------------------------------------
2028 procedure Warn_No_Exception_Propagation_Active
(N
: Node_Id
) is
2031 ("?pragma Restrictions (No_Exception_Propagation) in effect", N
);
2032 end Warn_No_Exception_Propagation_Active
;