1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2016, 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 Debug
; use Debug
;
28 with Einfo
; use Einfo
;
29 with Elists
; use Elists
;
30 with Errout
; use Errout
;
31 with Exp_Ch7
; use Exp_Ch7
;
32 with Exp_Intr
; use Exp_Intr
;
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
; Blk_Id
: Entity_Id
) is
103 Clean
: constant Entity_Id
:= Entity
(At_End_Proc
(HSS
));
107 Loc
: constant Source_Ptr
:= No_Location
;
108 -- Location used for expansion. We quite deliberately do not set a
109 -- specific source location for the expanded handler. This makes
110 -- sense since really the handler is not associated with specific
111 -- source. We used to set this to Sloc (Clean), but that caused
112 -- useless and annoying bouncing around of line numbers in the
113 -- debugger in some circumstances.
116 pragma Assert
(Present
(Clean
));
117 pragma Assert
(No
(Exception_Handlers
(HSS
)));
119 -- Back end exception schemes don't need explicit handlers to
120 -- trigger AT-END actions on exceptional paths.
122 if Back_End_Exceptions
then
126 -- Don't expand an At End handler if we have already had configurable
127 -- run-time violations, since likely this will just be a matter of
128 -- generating useless cascaded messages
130 if Configurable_Run_Time_Violations
> 0 then
134 -- Don't expand an At End handler if we are not allowing exceptions
135 -- or if exceptions are transformed into local gotos, and never
136 -- propagated (No_Exception_Propagation).
138 if No_Exception_Handlers_Set
then
142 if Present
(Blk_Id
) then
147 Make_Others_Choice
(Loc
);
148 Set_All_Others
(Ohandle
);
151 Make_Procedure_Call_Statement
(Loc
,
152 Name
=> New_Occurrence_Of
(Clean
, Loc
)));
154 -- Generate reraise statement as last statement of AT-END handler,
155 -- unless we are under control of No_Exception_Propagation, in which
156 -- case no exception propagation is possible anyway, so we do not need
157 -- a reraise (the AT END handler in this case is only for normal exits
158 -- not for exceptional exits). Also, we flag the Reraise statement as
159 -- being part of an AT END handler to prevent signalling this reraise
160 -- as a violation of the restriction when it is not set.
162 if not Restriction_Active
(No_Exception_Propagation
) then
164 Rstm
: constant Node_Id
:= Make_Raise_Statement
(Loc
);
166 Set_From_At_End
(Rstm
);
167 Append_To
(Stmnts
, Rstm
);
171 Set_Exception_Handlers
(HSS
, New_List
(
172 Make_Implicit_Exception_Handler
(Loc
,
173 Exception_Choices
=> New_List
(Ohandle
),
174 Statements
=> Stmnts
)));
176 Analyze_List
(Stmnts
, Suppress
=> All_Checks
);
177 Expand_Exception_Handlers
(HSS
);
179 if Present
(Blk_Id
) then
182 end Expand_At_End_Handler
;
184 -------------------------------
185 -- Expand_Exception_Handlers --
186 -------------------------------
188 procedure Expand_Exception_Handlers
(HSS
: Node_Id
) is
189 Handlrs
: constant List_Id
:= Exception_Handlers
(HSS
);
190 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
192 Others_Choice
: Boolean;
194 Next_Handler
: Node_Id
;
196 procedure Expand_Local_Exception_Handlers
;
197 -- This procedure handles the expansion of exception handlers for the
198 -- optimization of local raise statements into goto statements.
200 procedure Prepend_Call_To_Handler
202 Args
: List_Id
:= No_List
);
203 -- Routine to prepend a call to the procedure referenced by Proc at
204 -- the start of the handler code for the current Handler.
206 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
);
207 -- Raise_S is a raise statement (possibly expanded, and possibly of the
208 -- form of a Raise_xxx_Error node with a condition. This procedure is
209 -- called to replace the raise action with the (already analyzed) goto
210 -- statement passed as Goto_L1. This procedure also takes care of the
211 -- requirement of inserting a Local_Raise call where possible.
213 -------------------------------------
214 -- Expand_Local_Exception_Handlers --
215 -------------------------------------
217 -- There are two cases for this transformation. First the case of
218 -- explicit raise statements. For this case, the transformation we do
219 -- looks like this. Right now we have for example (where L1, L2 are
224 -- raise_exception (excep1'identity); -- was raise excep1
226 -- raise_exception (excep2'identity); -- was raise excep2
235 -- This gets transformed into:
238 -- L1 : label; -- marked Exception_Junk
239 -- L2 : label; -- marked Exception_Junk
240 -- L3 : label; -- marked Exception_Junk
242 -- begin -- marked Exception_Junk
244 -- local_raise (excep1'address); -- was raise excep1
247 -- local_raise (excep2'address); -- was raise excep2
257 -- goto L3; -- skip handler if no raise, marked Exception_Junk
259 -- <<L1>> -- local excep target label, marked Exception_Junk
260 -- begin -- marked Exception_Junk
263 -- goto L3; -- marked Exception_Junk
265 -- <<L2>> -- marked Exception_Junk
266 -- begin -- marked Exception_Junk
269 -- goto L3; -- marked Exception_Junk
270 -- <<L3>> -- marked Exception_Junk
273 -- Note: the reason we wrap the original statement sequence in an
274 -- inner block is that there may be raise statements within the
275 -- sequence of statements in the handlers, and we must ensure that
276 -- these are properly handled, and in particular, such raise statements
277 -- must not reenter the same exception handlers.
279 -- If the restriction No_Exception_Propagation is in effect, then we
280 -- can omit the exception handlers.
283 -- L1 : label; -- marked Exception_Junk
284 -- L2 : label; -- marked Exception_Junk
285 -- L3 : label; -- marked Exception_Junk
287 -- begin -- marked Exception_Junk
289 -- local_raise (excep1'address); -- was raise excep1
292 -- local_raise (excep2'address); -- was raise excep2
297 -- goto L3; -- skip handler if no raise, marked Exception_Junk
299 -- <<L1>> -- local excep target label, marked Exception_Junk
300 -- begin -- marked Exception_Junk
303 -- goto L3; -- marked Exception_Junk
305 -- <<L2>> -- marked Exception_Junk
306 -- begin -- marked Exception_Junk
310 -- <<L3>> -- marked Exception_Junk
313 -- The second case is for exceptions generated by the back end in one
314 -- of three situations:
316 -- 1. Front end generates N_Raise_xxx_Error node
317 -- 2. Front end sets Do_xxx_Check flag in subexpression node
318 -- 3. Back end detects a situation where an exception is appropriate
320 -- In all these cases, the current processing in gigi is to generate a
321 -- call to the appropriate Rcheck_xx routine (where xx encodes both the
322 -- exception message and the exception to be raised, Constraint_Error,
323 -- Program_Error, or Storage_Error.
325 -- We could handle some subcases of 1 using the same front end expansion
326 -- into gotos, but even for case 1, we can't handle all cases, since
327 -- generating gotos in the middle of expressions is not possible (it's
328 -- possible at the gigi/gcc level, but not at the level of the GNAT
331 -- In any case, it seems easier to have a scheme which handles all three
332 -- cases in a uniform manner. So here is how we proceed in this case.
334 -- This procedure detects all handlers for these three exceptions,
335 -- Constraint_Error, Program_Error and Storage_Error (including WHEN
336 -- OTHERS handlers that cover one or more of these cases).
338 -- If the handler meets the requirements for being the target of a local
339 -- raise, then the front end does the expansion described previously,
340 -- creating a label to be used as a goto target to raise the exception.
341 -- However, no attempt is made in the front end to convert any related
342 -- raise statements into gotos, e.g. all N_Raise_xxx_Error nodes are
343 -- left unchanged and passed to the back end.
345 -- Instead, the front end generates three nodes
347 -- N_Push_Constraint_Error_Label
348 -- N_Push_Program_Error_Label
349 -- N_Push_Storage_Error_Label
351 -- The Push node is generated at the start of the statements
352 -- covered by the handler, and has as a parameter the label to be
353 -- used as the raise target.
355 -- N_Pop_Constraint_Error_Label
356 -- N_Pop_Program_Error_Label
357 -- N_Pop_Storage_Error_Label
359 -- The Pop node is generated at the end of the covered statements
360 -- and undoes the effect of the preceding corresponding Push node.
362 -- In the case where the handler does NOT meet the requirements, the
363 -- front end will still generate the Push and Pop nodes, but the label
364 -- field in the Push node will be empty signifying that for this region
365 -- of code, no optimization is possible.
367 -- These Push/Pop nodes are inhibited if No_Exception_Handlers is set
368 -- since they are useless in this case, and in CodePeer mode, where
369 -- they serve no purpose and can intefere with the analysis.
371 -- The back end must maintain three stacks, one for each exception case,
372 -- the Push node pushes an entry onto the corresponding stack, and Pop
373 -- node pops off the entry. Then instead of calling Rcheck_nn, if the
374 -- corresponding top stack entry has an non-empty label, a goto is
375 -- generated. This goto should be preceded by a call to Local_Raise as
378 -- An example of this transformation is as follows, given:
381 -- A : Integer range 1 .. 10;
385 -- when Constraint_Error =>
389 -- gets transformed to:
392 -- A : Integer range 1 .. 10;
399 -- %push_constraint_error_label (L1)
400 -- R1b : constant long_long_integer := long_long_integer?(b) +
401 -- long_long_integer?(c);
402 -- [constraint_error when
403 -- not (R1b in -16#8000_0000# .. 16#7FFF_FFFF#)
404 -- "overflow check failed"]
405 -- a := integer?(R1b);
406 -- %pop_constraint_error_Label
410 -- when constraint_error =>
414 -- goto L2; -- skip handler when exception not raised
415 -- <<L1>> -- target label for local exception
420 -- Note: the generated labels and goto statements all have the flag
421 -- Exception_Junk set True, so that Sem_Ch6.Check_Returns will ignore
422 -- this generated exception stuff when checking for missing return
423 -- statements (see circuitry in Check_Statement_Sequence).
425 -- Note: All of the processing described above occurs only if
426 -- restriction No_Exception_Propagation applies or debug flag .g is
429 CE_Locally_Handled
: Boolean := False;
430 SE_Locally_Handled
: Boolean := False;
431 PE_Locally_Handled
: Boolean := False;
432 -- These three flags indicate whether a handler for the corresponding
433 -- exception (CE=Constraint_Error, SE=Storage_Error, PE=Program_Error)
434 -- is present. If so the switch is set to True, the Exception_Label
435 -- field of the corresponding handler is set, and appropriate Push
436 -- and Pop nodes are inserted into the code.
438 Local_Expansion_Required
: Boolean := False;
439 -- Set True if we have at least one handler requiring local raise
440 -- expansion as described above.
442 procedure Expand_Local_Exception_Handlers
is
443 procedure Add_Exception_Label
(H
: Node_Id
);
444 -- H is an exception handler. First check for an Exception_Label
445 -- already allocated for H. If none, allocate one, set the field in
446 -- the handler node, add the label declaration, and set the flag
447 -- Local_Expansion_Required. Note: if Local_Raise_Not_OK is set
448 -- the call has no effect and Exception_Label is left empty.
450 procedure Add_Label_Declaration
(L
: Entity_Id
);
451 -- Add an implicit declaration of the given label to the declaration
452 -- list in the parent of the current sequence of handled statements.
455 Exc_Locally_Handled
: in out Boolean;
456 -- Flag indicating whether a local handler for this exception
457 -- has already been generated.
459 with function Make_Push_Label
(Loc
: Source_Ptr
) return Node_Id
;
460 -- Function to create a Push_xxx_Label node
462 with function Make_Pop_Label
(Loc
: Source_Ptr
) return Node_Id
;
463 -- Function to create a Pop_xxx_Label node
465 procedure Generate_Push_Pop
(H
: Node_Id
);
466 -- Common code for Generate_Push_Pop_xxx below, used to generate an
467 -- exception label and Push/Pop nodes for Constraint_Error,
468 -- Program_Error, or Storage_Error.
470 -------------------------
471 -- Add_Exception_Label --
472 -------------------------
474 procedure Add_Exception_Label
(H
: Node_Id
) is
476 if No
(Exception_Label
(H
))
477 and then not Local_Raise_Not_OK
(H
)
478 and then not Special_Exception_Package_Used
480 Local_Expansion_Required
:= True;
483 L
: constant Entity_Id
:= Make_Temporary
(Sloc
(H
), 'L');
485 Set_Exception_Label
(H
, L
);
486 Add_Label_Declaration
(L
);
489 end Add_Exception_Label
;
491 ---------------------------
492 -- Add_Label_Declaration --
493 ---------------------------
495 procedure Add_Label_Declaration
(L
: Entity_Id
) is
496 P
: constant Node_Id
:= Parent
(HSS
);
498 Decl_L
: constant Node_Id
:=
499 Make_Implicit_Label_Declaration
(Loc
,
500 Defining_Identifier
=> L
);
503 if Declarations
(P
) = No_List
then
504 Set_Declarations
(P
, Empty_List
);
507 Append
(Decl_L
, Declarations
(P
));
509 end Add_Label_Declaration
;
511 -----------------------
512 -- Generate_Push_Pop --
513 -----------------------
515 procedure Generate_Push_Pop
(H
: Node_Id
) is
517 if Restriction_Active
(No_Exception_Handlers
)
518 or else CodePeer_Mode
523 if Exc_Locally_Handled
then
526 Exc_Locally_Handled
:= True;
529 Add_Exception_Label
(H
);
532 F
: constant Node_Id
:= First
(Statements
(HSS
));
533 L
: constant Node_Id
:= Last
(Statements
(HSS
));
535 Push
: constant Node_Id
:= Make_Push_Label
(Sloc
(F
));
536 Pop
: constant Node_Id
:= Make_Pop_Label
(Sloc
(L
));
539 -- We make sure that a call to Get_Local_Raise_Call_Entity is
540 -- made during front end processing, so that when we need it
541 -- in the back end, it will already be available and loaded.
543 Discard_Node
(Get_Local_Raise_Call_Entity
);
545 -- Prepare and insert Push and Pop nodes
547 Set_Exception_Label
(Push
, Exception_Label
(H
));
548 Insert_Before
(F
, Push
);
551 Insert_After
(L
, Pop
);
554 end Generate_Push_Pop
;
556 -- Local declarations
558 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
559 Stmts
: List_Id
:= No_List
;
563 procedure Generate_Push_Pop_For_Constraint_Error
is
564 new Generate_Push_Pop
565 (Exc_Locally_Handled
=> CE_Locally_Handled
,
566 Make_Push_Label
=> Make_Push_Constraint_Error_Label
,
567 Make_Pop_Label
=> Make_Pop_Constraint_Error_Label
);
568 -- If no Push/Pop has been generated for CE yet, then set the flag
569 -- CE_Locally_Handled, allocate an Exception_Label for handler H (if
570 -- not already done), and generate Push/Pop nodes for the exception
571 -- label at the start and end of the statements of HSS.
573 procedure Generate_Push_Pop_For_Program_Error
is
574 new Generate_Push_Pop
575 (Exc_Locally_Handled
=> PE_Locally_Handled
,
576 Make_Push_Label
=> Make_Push_Program_Error_Label
,
577 Make_Pop_Label
=> Make_Pop_Program_Error_Label
);
578 -- If no Push/Pop has been generated for PE yet, then set the flag
579 -- PE_Locally_Handled, allocate an Exception_Label for handler H (if
580 -- not already done), and generate Push/Pop nodes for the exception
581 -- label at the start and end of the statements of HSS.
583 procedure Generate_Push_Pop_For_Storage_Error
is
584 new Generate_Push_Pop
585 (Exc_Locally_Handled
=> SE_Locally_Handled
,
586 Make_Push_Label
=> Make_Push_Storage_Error_Label
,
587 Make_Pop_Label
=> Make_Pop_Storage_Error_Label
);
588 -- If no Push/Pop has been generated for SE yet, then set the flag
589 -- SE_Locally_Handled, allocate an Exception_Label for handler H (if
590 -- not already done), and generate Push/Pop nodes for the exception
591 -- label at the start and end of the statements of HSS.
593 -- Start of processing for Expand_Local_Exception_Handlers
596 -- No processing if all exception handlers will get removed
598 if Debug_Flag_Dot_X
then
602 -- See for each handler if we have any local raises to expand
604 Handler
:= First_Non_Pragma
(Handlrs
);
605 while Present
(Handler
) loop
607 -- Note, we do not test Local_Raise_Not_OK here, because in the
608 -- case of Push/Pop generation we want to generate push with a
609 -- null label. The Add_Exception_Label routine has no effect if
610 -- Local_Raise_Not_OK is set, so this works as required.
612 if Present
(Local_Raise_Statements
(Handler
)) then
613 Add_Exception_Label
(Handler
);
616 -- If we are doing local raise to goto optimization (restriction
617 -- No_Exception_Propagation set or debug flag .g set), then check
618 -- to see if handler handles CE, PE, SE and if so generate the
619 -- appropriate push/pop sequence for the back end.
622 or else Restriction_Active
(No_Exception_Propagation
))
623 and then Has_Local_Raise
(Handler
)
625 Choice
:= First
(Exception_Choices
(Handler
));
626 while Present
(Choice
) loop
627 if Nkind
(Choice
) = N_Others_Choice
628 and then not All_Others
(Choice
)
630 Generate_Push_Pop_For_Constraint_Error
(Handler
);
631 Generate_Push_Pop_For_Program_Error
(Handler
);
632 Generate_Push_Pop_For_Storage_Error
(Handler
);
634 elsif Is_Entity_Name
(Choice
) then
635 Excep
:= Get_Renamed_Entity
(Entity
(Choice
));
637 if Excep
= Standard_Constraint_Error
then
638 Generate_Push_Pop_For_Constraint_Error
(Handler
);
639 elsif Excep
= Standard_Program_Error
then
640 Generate_Push_Pop_For_Program_Error
(Handler
);
641 elsif Excep
= Standard_Storage_Error
then
642 Generate_Push_Pop_For_Storage_Error
(Handler
);
650 Next_Non_Pragma
(Handler
);
653 -- Nothing to do if no handlers requiring the goto transformation
655 if not (Local_Expansion_Required
) then
659 -- Prepare to do the transformation
662 -- L3 is the label to exit the HSS
664 L3_Dent
: constant Entity_Id
:= Make_Temporary
(Loc
, 'L');
666 Labl_L3
: constant Node_Id
:=
668 Identifier
=> New_Occurrence_Of
(L3_Dent
, Loc
));
674 Set_Exception_Junk
(Labl_L3
);
675 Add_Label_Declaration
(L3_Dent
);
677 -- Wrap existing statements and handlers in an inner block
680 Make_Block_Statement
(Loc
,
681 Handled_Statement_Sequence
=> Relocate_Node
(HSS
));
682 Set_Exception_Junk
(Blk_Stm
);
685 Make_Handled_Sequence_Of_Statements
(Loc
,
686 Statements
=> New_List
(Blk_Stm
),
687 End_Label
=> Relocate_Node
(End_Label
(HSS
))));
689 -- Set block statement as analyzed, we don't want to actually call
690 -- Analyze on this block, it would cause a recursion in exception
691 -- handler processing which would mess things up.
693 Set_Analyzed
(Blk_Stm
);
695 -- Now loop through the exception handlers to deal with those that
696 -- are targets of local raise statements.
698 Handler
:= First_Non_Pragma
(Handlrs
);
699 while Present
(Handler
) loop
700 if Present
(Exception_Label
(Handler
)) then
702 -- This handler needs the goto expansion
705 Loc
: constant Source_Ptr
:= Sloc
(Handler
);
707 -- L1 is the start label for this handler
709 L1_Dent
: constant Entity_Id
:= Exception_Label
(Handler
);
711 Labl_L1
: constant Node_Id
:=
714 New_Occurrence_Of
(L1_Dent
, Loc
));
716 -- Jump to L1 to be used as replacement for the original
717 -- handler (used in the case where exception propagation
720 Name_L1
: constant Node_Id
:=
721 New_Occurrence_Of
(L1_Dent
, Loc
);
723 Goto_L1
: constant Node_Id
:=
724 Make_Goto_Statement
(Loc
,
727 -- Jump to L3 to be used at the end of handler
729 Name_L3
: constant Node_Id
:=
730 New_Occurrence_Of
(L3_Dent
, Loc
);
732 Goto_L3
: constant Node_Id
:=
733 Make_Goto_Statement
(Loc
,
736 H_Stmts
: constant List_Id
:= Statements
(Handler
);
739 Set_Exception_Junk
(Labl_L1
);
740 Set_Exception_Junk
(Goto_L3
);
742 -- Note: we do NOT set Exception_Junk in Goto_L1, since
743 -- this is a real transfer of control that we want the
744 -- Sem_Ch6.Check_Returns procedure to recognize properly.
746 -- Replace handler by a goto L1. We can mark this as
747 -- analyzed since it is fully formed, and we don't
748 -- want it going through any further checks. We save
749 -- the last statement location in the goto L1 node for
750 -- the benefit of Sem_Ch6.Check_Returns.
752 Set_Statements
(Handler
, New_List
(Goto_L1
));
753 Set_Analyzed
(Goto_L1
);
754 Set_Etype
(Name_L1
, Standard_Void_Type
);
756 -- Now replace all the raise statements by goto L1
758 if Present
(Local_Raise_Statements
(Handler
)) then
759 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
760 while Present
(Relmt
) loop
762 Raise_S
: constant Node_Id
:= Node
(Relmt
);
763 RLoc
: constant Source_Ptr
:= Sloc
(Raise_S
);
764 Name_L1
: constant Node_Id
:=
765 New_Occurrence_Of
(L1_Dent
, Loc
);
766 Goto_L1
: constant Node_Id
:=
767 Make_Goto_Statement
(RLoc
,
771 -- Replace raise by goto L1
773 Set_Analyzed
(Goto_L1
);
774 Set_Etype
(Name_L1
, Standard_Void_Type
);
775 Replace_Raise_By_Goto
(Raise_S
, Goto_L1
);
782 -- Add a goto L3 at end of statement list in block. The
783 -- first time, this is what skips over the exception
784 -- handlers in the normal case. Subsequent times, it
785 -- terminates the execution of the previous handler code,
786 -- and skips subsequent handlers.
788 Stmts
:= Statements
(HSS
);
790 Insert_After
(Last
(Stmts
), Goto_L3
);
791 Set_Analyzed
(Goto_L3
);
792 Set_Etype
(Name_L3
, Standard_Void_Type
);
794 -- Now we drop the label that marks the handler start,
795 -- followed by the statements of the handler.
797 Set_Etype
(Identifier
(Labl_L1
), Standard_Void_Type
);
799 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L1
);
802 Loc
: constant Source_Ptr
:= Sloc
(First
(H_Stmts
));
803 Blk
: constant Node_Id
:=
804 Make_Block_Statement
(Loc
,
805 Handled_Statement_Sequence
=>
806 Make_Handled_Sequence_Of_Statements
(Loc
,
807 Statements
=> H_Stmts
));
809 Set_Exception_Junk
(Blk
);
810 Insert_After_And_Analyze
(Last
(Stmts
), Blk
);
814 -- Here if we have local raise statements but the handler is
815 -- not suitable for processing with a local raise. In this
816 -- case we have to generate possible diagnostics.
818 elsif Has_Local_Raise
(Handler
)
819 and then Local_Raise_Statements
(Handler
) /= No_Elist
821 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
822 while Present
(Relmt
) loop
823 Warn_If_No_Propagation
(Node
(Relmt
));
831 -- Only remaining step is to drop the L3 label and we are done
833 Set_Etype
(Identifier
(Labl_L3
), Standard_Void_Type
);
835 -- If we had at least one handler, then we drop the label after
836 -- the last statement of that handler.
838 if Stmts
/= No_List
then
839 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L3
);
841 -- Otherwise we have removed all the handlers (this results from
842 -- use of pragma Restrictions (No_Exception_Propagation), and we
843 -- drop the label at the end of the statements of the HSS.
846 Insert_After_And_Analyze
(Last
(Statements
(HSS
)), Labl_L3
);
851 end Expand_Local_Exception_Handlers
;
853 -----------------------------
854 -- Prepend_Call_To_Handler --
855 -----------------------------
857 procedure Prepend_Call_To_Handler
859 Args
: List_Id
:= No_List
)
861 Ent
: constant Entity_Id
:= RTE
(Proc
);
864 -- If we have no Entity, then we are probably in no run time mode or
865 -- some weird error has occurred. In either case do nothing. Note use
866 -- of No_Location to hide this code from the debugger, so single
867 -- stepping doesn't jump back and forth.
869 if Present
(Ent
) then
871 Call
: constant Node_Id
:=
872 Make_Procedure_Call_Statement
(No_Location
,
873 Name
=> New_Occurrence_Of
(RTE
(Proc
), No_Location
),
874 Parameter_Associations
=> Args
);
877 Prepend_To
(Statements
(Handler
), Call
);
878 Analyze
(Call
, Suppress
=> All_Checks
);
881 end Prepend_Call_To_Handler
;
883 ---------------------------
884 -- Replace_Raise_By_Goto --
885 ---------------------------
887 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
) is
888 Loc
: constant Source_Ptr
:= Sloc
(Raise_S
);
895 -- If we have a null statement, it means that there is no replacement
896 -- needed (typically this results from a suppressed check).
898 if Nkind
(Raise_S
) = N_Null_Statement
then
901 -- Test for Raise_xxx_Error
903 elsif Nkind
(Raise_S
) = N_Raise_Constraint_Error
then
904 Excep
:= Standard_Constraint_Error
;
905 Cond
:= Condition
(Raise_S
);
907 elsif Nkind
(Raise_S
) = N_Raise_Storage_Error
then
908 Excep
:= Standard_Storage_Error
;
909 Cond
:= Condition
(Raise_S
);
911 elsif Nkind
(Raise_S
) = N_Raise_Program_Error
then
912 Excep
:= Standard_Program_Error
;
913 Cond
:= Condition
(Raise_S
);
915 -- The only other possibility is a node that is or used to be a
916 -- simple raise statement.
919 Orig
:= Original_Node
(Raise_S
);
920 pragma Assert
(Nkind
(Orig
) = N_Raise_Statement
921 and then Present
(Name
(Orig
))
922 and then No
(Expression
(Orig
)));
923 Excep
:= Entity
(Name
(Orig
));
927 -- Here Excep is the exception to raise, and Cond is the condition
928 -- First prepare the call to Local_Raise (excep'address).
930 if RTE_Available
(RE_Local_Raise
) then
932 Make_Procedure_Call_Statement
(Loc
,
933 Name
=> New_Occurrence_Of
(RTE
(RE_Local_Raise
), Loc
),
934 Parameter_Associations
=> New_List
(
935 Unchecked_Convert_To
(RTE
(RE_Address
),
936 Make_Attribute_Reference
(Loc
,
937 Prefix
=> New_Occurrence_Of
(Excep
, Loc
),
938 Attribute_Name
=> Name_Identity
))));
940 -- Use null statement if Local_Raise not available
944 Make_Null_Statement
(Loc
);
947 -- If there is no condition, we rewrite as
950 -- Local_Raise (excep'Identity);
956 Make_Block_Statement
(Loc
,
957 Handled_Statement_Sequence
=>
958 Make_Handled_Sequence_Of_Statements
(Loc
,
959 Statements
=> New_List
(LR
, Goto_L1
))));
960 Set_Exception_Junk
(Raise_S
);
962 -- If there is a condition, we rewrite as
965 -- Local_Raise (excep'Identity);
971 Make_If_Statement
(Loc
,
973 Then_Statements
=> New_List
(LR
, Goto_L1
)));
977 end Replace_Raise_By_Goto
;
979 -- Start of processing for Expand_Exception_Handlers
982 Expand_Local_Exception_Handlers
;
984 -- Loop through handlers
986 Handler
:= First_Non_Pragma
(Handlrs
);
987 Handler_Loop
: while Present
(Handler
) loop
988 Process_Statements_For_Controlled_Objects
(Handler
);
990 Next_Handler
:= Next_Non_Pragma
(Handler
);
992 -- Remove source handler if gnat debug flag .x is set
994 if Debug_Flag_Dot_X
and then Comes_From_Source
(Handler
) then
997 -- Remove handler if no exception propagation, generating a warning
998 -- if a source generated handler was not the target of a local raise.
1001 if Restriction_Active
(No_Exception_Propagation
)
1002 and then not Has_Local_Raise
(Handler
)
1003 and then Comes_From_Source
(Handler
)
1004 and then Warn_On_Non_Local_Exception
1006 Warn_No_Exception_Propagation_Active
(Handler
);
1008 ("\?X?this handler can never be entered, "
1009 & "and has been removed", Handler
);
1012 if No_Exception_Propagation_Active
then
1015 -- Exception handler is active and retained and must be processed
1018 -- If an exception occurrence is present, then we must declare
1019 -- it and initialize it from the value stored in the TSD
1022 -- name : Exception_Occurrence;
1024 -- Save_Occurrence (name, Get_Current_Excep.all)
1028 -- This expansion is only performed when using front-end
1029 -- exceptions. Gigi will insert a call to initialize the
1030 -- choice parameter.
1032 if Present
(Choice_Parameter
(Handler
))
1033 and then (Front_End_Exceptions
1034 or else CodePeer_Mode
)
1037 Cparm
: constant Entity_Id
:= Choice_Parameter
(Handler
);
1038 Cloc
: constant Source_Ptr
:= Sloc
(Cparm
);
1039 Hloc
: constant Source_Ptr
:= Sloc
(Handler
);
1043 -- Note: No_Location used to hide code from the debugger,
1044 -- so single stepping doesn't jump back and forth.
1047 Make_Procedure_Call_Statement
(No_Location
,
1050 (RTE
(RE_Save_Occurrence
), No_Location
),
1051 Parameter_Associations
=> New_List
(
1052 New_Occurrence_Of
(Cparm
, No_Location
),
1053 Make_Explicit_Dereference
(No_Location
,
1055 Make_Function_Call
(No_Location
,
1057 Make_Explicit_Dereference
(No_Location
,
1060 (RTE
(RE_Get_Current_Excep
),
1063 Mark_Rewrite_Insertion
(Save
);
1064 Prepend
(Save
, Statements
(Handler
));
1067 Make_Object_Declaration
(Cloc
,
1068 Defining_Identifier
=> Cparm
,
1069 Object_Definition
=>
1071 (RTE
(RE_Exception_Occurrence
), Cloc
));
1072 Set_No_Initialization
(Obj_Decl
, True);
1075 Make_Exception_Handler
(Hloc
,
1076 Choice_Parameter
=> Empty
,
1077 Exception_Choices
=> Exception_Choices
(Handler
),
1078 Statements
=> New_List
(
1079 Make_Block_Statement
(Hloc
,
1080 Declarations
=> New_List
(Obj_Decl
),
1081 Handled_Statement_Sequence
=>
1082 Make_Handled_Sequence_Of_Statements
(Hloc
,
1083 Statements
=> Statements
(Handler
))))));
1085 -- Local raise statements can't occur, since exception
1086 -- handlers with choice parameters are not allowed when
1087 -- No_Exception_Propagation applies, so set attributes
1090 Set_Local_Raise_Statements
(Handler
, No_Elist
);
1091 Set_Local_Raise_Not_OK
(Handler
);
1094 (Statements
(Handler
), Suppress
=> All_Checks
);
1098 -- For the normal case, we have to worry about the state of
1099 -- abort deferral. Generally, we defer abort during runtime
1100 -- handling of exceptions. When control is passed to the
1101 -- handler, then in the normal case we undefer aborts. In
1102 -- any case this entire handling is relevant only if aborts
1106 and then not ZCX_Exceptions
1108 -- There are some special cases in which we do not do the
1109 -- undefer. In particular a finalization (AT END) handler
1110 -- wants to operate with aborts still deferred.
1112 -- We also suppress the call if this is the special handler
1113 -- for Abort_Signal, since if we are aborting, we want to
1114 -- keep aborts deferred (one abort is enough).
1116 -- If abort really needs to be deferred the expander must
1117 -- add this call explicitly, see
1118 -- Expand_N_Asynchronous_Select.
1121 Nkind
(First
(Exception_Choices
(Handler
))) =
1125 or else Entity
(First
(Exception_Choices
(Handler
))) /=
1130 All_Others
(First
(Exception_Choices
(Handler
))))
1132 Prepend_Call_To_Handler
(RE_Abort_Undefer
);
1138 Handler
:= Next_Handler
;
1139 end loop Handler_Loop
;
1141 -- If all handlers got removed, then remove the list. Note we cannot
1142 -- reference HSS here, since expanding local handlers may have buried
1143 -- the handlers in an inner block.
1145 if Is_Empty_List
(Handlrs
) then
1146 Set_Exception_Handlers
(Parent
(Handlrs
), No_List
);
1148 end Expand_Exception_Handlers
;
1150 ------------------------------------
1151 -- Expand_N_Exception_Declaration --
1152 ------------------------------------
1155 -- exceptE : constant String := "A.B.EXCEP"; -- static data
1156 -- except : exception_data :=
1157 -- (Handled_By_Other => False,
1159 -- Name_Length => exceptE'Length,
1160 -- Full_Name => exceptE'Address,
1161 -- HTable_Ptr => null,
1162 -- Foreign_Data => null,
1163 -- Raise_Hook => null);
1165 -- (protecting test only needed if not at library level)
1167 -- exceptF : Boolean := True -- static data
1169 -- exceptF := False;
1170 -- Register_Exception (except'Unchecked_Access);
1173 procedure Expand_N_Exception_Declaration
(N
: Node_Id
) is
1174 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
1175 Loc
: constant Source_Ptr
:= Sloc
(N
);
1177 Flag_Id
: Entity_Id
;
1180 procedure Force_Static_Allocation_Of_Referenced_Objects
1181 (Aggregate
: Node_Id
);
1182 -- A specialized solution to one particular case of an ugly problem
1184 -- The given aggregate includes an Unchecked_Conversion as one of the
1185 -- component values. The call to Analyze_And_Resolve below ends up
1186 -- calling Exp_Ch4.Expand_N_Unchecked_Type_Conversion, which may decide
1187 -- to introduce a (constant) temporary and then obtain the component
1188 -- value by evaluating the temporary.
1190 -- In the case of an exception declared within a subprogram (or any
1191 -- other dynamic scope), this is a bad transformation. The exception
1192 -- object is marked as being Statically_Allocated but the temporary is
1193 -- not. If the initial value of a Statically_Allocated declaration
1194 -- references a dynamically allocated object, this prevents static
1195 -- initialization of the object.
1197 -- We cope with this here by marking the temporary Statically_Allocated.
1198 -- It might seem cleaner to generalize this utility and then use it to
1199 -- enforce a rule that the entities referenced in the declaration of any
1200 -- "hoisted" (i.e., Is_Statically_Allocated and not Is_Library_Level)
1201 -- entity must also be either Library_Level or hoisted. It turns out
1202 -- that this would be incompatible with the current treatment of an
1203 -- object which is local to a subprogram, subject to an Export pragma,
1204 -- not subject to an address clause, and whose declaration contains
1205 -- references to other local (non-hoisted) objects (e.g., in the initial
1206 -- value expression).
1208 ---------------------------------------------------
1209 -- Force_Static_Allocation_Of_Referenced_Objects --
1210 ---------------------------------------------------
1212 procedure Force_Static_Allocation_Of_Referenced_Objects
1213 (Aggregate
: Node_Id
)
1215 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
;
1216 -- If the given node references a dynamically allocated object, then
1217 -- correct the declaration of the object.
1223 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
is
1225 if Nkind
(N
) in N_Has_Entity
1226 and then Present
(Entity
(N
))
1227 and then not Is_Library_Level_Entity
(Entity
(N
))
1229 -- Note: the following test is not needed but it seems cleaner
1230 -- to do this test (this would be more important if procedure
1231 -- Force_Static_Allocation_Of_Referenced_Objects recursively
1232 -- traversed the declaration of an entity after marking it as
1233 -- statically allocated).
1235 and then not Is_Statically_Allocated
(Entity
(N
))
1237 Set_Is_Statically_Allocated
(Entity
(N
));
1243 procedure Fixup_Tree
is new Traverse_Proc
(Fixup_Node
);
1245 -- Start of processing for Force_Static_Allocation_Of_Referenced_Objects
1248 Fixup_Tree
(Aggregate
);
1249 end Force_Static_Allocation_Of_Referenced_Objects
;
1251 -- Start of processing for Expand_N_Exception_Declaration
1254 -- Nothing to do when generating C code
1256 if Generate_C_Code
then
1260 -- Definition of the external name: nam : constant String := "A.B.NAME";
1263 Make_Defining_Identifier
(Loc
, New_External_Name
(Chars
(Id
), 'E'));
1266 Make_Object_Declaration
(Loc
,
1267 Defining_Identifier
=> Ex_Id
,
1268 Constant_Present
=> True,
1269 Object_Definition
=> New_Occurrence_Of
(Standard_String
, Loc
),
1271 Make_String_Literal
(Loc
,
1272 Strval
=> Fully_Qualified_Name_String
(Id
))));
1274 Set_Is_Statically_Allocated
(Ex_Id
);
1276 -- Create the aggregate list for type Standard.Exception_Type:
1277 -- Handled_By_Other component: False
1280 Append_To
(L
, New_Occurrence_Of
(Standard_False
, Loc
));
1282 -- Lang component: 'A'
1285 Make_Character_Literal
(Loc
,
1287 Char_Literal_Value
=> UI_From_Int
(Character'Pos ('A'))));
1289 -- Name_Length component: Nam'Length
1292 Make_Attribute_Reference
(Loc
,
1293 Prefix
=> New_Occurrence_Of
(Ex_Id
, Loc
),
1294 Attribute_Name
=> Name_Length
));
1296 -- Full_Name component: Standard.A_Char!(Nam'Address)
1298 -- The unchecked conversion causes capacity issues for CodePeer in some
1299 -- cases and is never useful, so we set the Full_Name component to null
1300 -- instead for CodePeer.
1302 if CodePeer_Mode
then
1303 Append_To
(L
, Make_Null
(Loc
));
1305 Append_To
(L
, Unchecked_Convert_To
(Standard_A_Char
,
1306 Make_Attribute_Reference
(Loc
,
1307 Prefix
=> New_Occurrence_Of
(Ex_Id
, Loc
),
1308 Attribute_Name
=> Name_Address
)));
1311 -- HTable_Ptr component: null
1313 Append_To
(L
, Make_Null
(Loc
));
1315 -- Foreign_Data component: null
1317 Append_To
(L
, Make_Null
(Loc
));
1319 -- Raise_Hook component: null
1321 Append_To
(L
, Make_Null
(Loc
));
1323 Set_Expression
(N
, Make_Aggregate
(Loc
, Expressions
=> L
));
1324 Analyze_And_Resolve
(Expression
(N
), Etype
(Id
));
1326 Force_Static_Allocation_Of_Referenced_Objects
(Expression
(N
));
1328 -- Register_Exception (except'Unchecked_Access);
1330 if not No_Exception_Handlers_Set
1331 and then not Restriction_Active
(No_Exception_Registration
)
1334 Make_Procedure_Call_Statement
(Loc
,
1336 New_Occurrence_Of
(RTE
(RE_Register_Exception
), Loc
),
1337 Parameter_Associations
=> New_List
(
1338 Unchecked_Convert_To
(RTE
(RE_Exception_Data_Ptr
),
1339 Make_Attribute_Reference
(Loc
,
1340 Prefix
=> New_Occurrence_Of
(Id
, Loc
),
1341 Attribute_Name
=> Name_Unrestricted_Access
)))));
1343 Set_Register_Exception_Call
(Id
, First
(L
));
1345 if not Is_Library_Level_Entity
(Id
) then
1347 Make_Defining_Identifier
(Loc
,
1348 Chars
=> New_External_Name
(Chars
(Id
), 'F'));
1351 Make_Object_Declaration
(Loc
,
1352 Defining_Identifier
=> Flag_Id
,
1353 Object_Definition
=>
1354 New_Occurrence_Of
(Standard_Boolean
, Loc
),
1356 New_Occurrence_Of
(Standard_True
, Loc
)));
1358 Set_Is_Statically_Allocated
(Flag_Id
);
1361 Make_Assignment_Statement
(Loc
,
1362 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1363 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
1365 Insert_After_And_Analyze
(N
,
1366 Make_Implicit_If_Statement
(N
,
1367 Condition
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1368 Then_Statements
=> L
));
1371 Insert_List_After_And_Analyze
(N
, L
);
1374 end Expand_N_Exception_Declaration
;
1376 ---------------------------------------------
1377 -- Expand_N_Handled_Sequence_Of_Statements --
1378 ---------------------------------------------
1380 procedure Expand_N_Handled_Sequence_Of_Statements
(N
: Node_Id
) is
1382 -- Expand exception handlers
1384 if Present
(Exception_Handlers
(N
))
1385 and then not Restriction_Active
(No_Exception_Handlers
)
1387 Expand_Exception_Handlers
(N
);
1390 -- If local exceptions are being expanded, the previous call will
1391 -- have rewritten the construct as a block and reanalyzed it. No
1392 -- further expansion is needed.
1394 if Analyzed
(N
) then
1398 -- Add clean up actions if required
1400 if not Nkind_In
(Parent
(N
), N_Package_Body
,
1402 N_Extended_Return_Statement
)
1403 and then not Delay_Cleanups
(Current_Scope
)
1405 -- No cleanup action needed in thunks associated with interfaces
1406 -- because they only displace the pointer to the object.
1408 and then not Is_Thunk
(Current_Scope
)
1410 Expand_Cleanup_Actions
(Parent
(N
));
1412 Set_First_Real_Statement
(N
, First
(Statements
(N
)));
1414 end Expand_N_Handled_Sequence_Of_Statements
;
1416 -------------------------------------
1417 -- Expand_N_Raise_Constraint_Error --
1418 -------------------------------------
1420 procedure Expand_N_Raise_Constraint_Error
(N
: Node_Id
) is
1422 -- We adjust the condition to deal with the C/Fortran boolean case. This
1423 -- may well not be necessary, as all such conditions are generated by
1424 -- the expander and probably are all standard boolean, but who knows
1425 -- what strange optimization in future may require this adjustment.
1427 Adjust_Condition
(Condition
(N
));
1429 -- Now deal with possible local raise handling
1431 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
1432 end Expand_N_Raise_Constraint_Error
;
1434 -------------------------------
1435 -- Expand_N_Raise_Expression --
1436 -------------------------------
1438 procedure Expand_N_Raise_Expression
(N
: Node_Id
) is
1439 Loc
: constant Source_Ptr
:= Sloc
(N
);
1440 Typ
: constant Entity_Id
:= Etype
(N
);
1444 Possible_Local_Raise
(N
, Entity
(Name
(N
)));
1446 -- Later we must teach the back end/gigi how to deal with this, but
1447 -- for now we will assume the type is Standard_Boolean and transform
1451 -- raise X [with string]
1453 -- raise Constraint_Error;
1455 -- unless the flag Convert_To_Return_False is set, in which case
1456 -- the transformation is to:
1461 -- raise Constraint_Error;
1463 -- The raise constraint error can never be executed. It is just a dummy
1464 -- node that can be labeled with an arbitrary type.
1466 RCE
:= Make_Raise_Constraint_Error
(Loc
, Reason
=> CE_Explicit_Raise
);
1467 Set_Etype
(RCE
, Typ
);
1469 if Convert_To_Return_False
(N
) then
1471 Make_Expression_With_Actions
(Loc
,
1472 Actions
=> New_List
(
1473 Make_Simple_Return_Statement
(Loc
,
1474 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
))),
1475 Expression
=> RCE
));
1479 Make_Expression_With_Actions
(Loc
,
1480 Actions
=> New_List
(
1481 Make_Raise_Statement
(Loc
,
1483 Expression
=> Expression
(N
))),
1484 Expression
=> RCE
));
1487 Analyze_And_Resolve
(N
, Typ
);
1488 end Expand_N_Raise_Expression
;
1490 ----------------------------------
1491 -- Expand_N_Raise_Program_Error --
1492 ----------------------------------
1494 procedure Expand_N_Raise_Program_Error
(N
: Node_Id
) is
1496 -- We adjust the condition to deal with the C/Fortran boolean case. This
1497 -- may well not be necessary, as all such conditions are generated by
1498 -- the expander and probably are all standard boolean, but who knows
1499 -- what strange optimization in future may require this adjustment.
1501 Adjust_Condition
(Condition
(N
));
1503 -- Now deal with possible local raise handling
1505 Possible_Local_Raise
(N
, Standard_Program_Error
);
1506 end Expand_N_Raise_Program_Error
;
1508 ------------------------------
1509 -- Expand_N_Raise_Statement --
1510 ------------------------------
1512 procedure Expand_N_Raise_Statement
(N
: Node_Id
) is
1513 Loc
: constant Source_Ptr
:= Sloc
(N
);
1521 -- Processing for locally handled exception (exclude reraise case)
1523 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1525 or else Restriction_Active
(No_Exception_Propagation
)
1527 -- If we have a local handler, then note that this is potentially
1528 -- able to be transformed into a goto statement.
1530 H
:= Find_Local_Handler
(Entity
(Name
(N
)), N
);
1533 if Local_Raise_Statements
(H
) = No_Elist
then
1534 Set_Local_Raise_Statements
(H
, New_Elmt_List
);
1537 -- Append the new entry if it is not there already. Sometimes
1538 -- we have situations where due to reexpansion, the same node
1539 -- is analyzed twice and would otherwise be added twice.
1541 Append_Unique_Elmt
(N
, Local_Raise_Statements
(H
));
1542 Set_Has_Local_Raise
(H
);
1544 -- If no local handler, then generate no propagation warning
1547 Warn_If_No_Propagation
(N
);
1553 -- If a string expression is present, then the raise statement is
1554 -- converted to a call:
1555 -- Raise_Exception (exception-name'Identity, string);
1556 -- and there is nothing else to do.
1558 if Present
(Expression
(N
)) then
1560 -- Adjust message to deal with Prefix_Exception_Messages. We only
1561 -- add the prefix to string literals, if the message is being
1562 -- constructed, we assume it already deals with uniqueness.
1564 if Prefix_Exception_Messages
1565 and then Nkind
(Expression
(N
)) = N_String_Literal
1568 Buf
: Bounded_String
;
1570 Add_Source_Info
(Buf
, Loc
, Name_Enclosing_Entity
);
1572 Append
(Buf
, Strval
(Expression
(N
)));
1573 Rewrite
(Expression
(N
), Make_String_Literal
(Loc
, +Buf
));
1574 Analyze_And_Resolve
(Expression
(N
), Standard_String
);
1578 -- Avoid passing exception-name'identity in runtimes in which this
1579 -- argument is not used. This avoids generating undefined references
1580 -- to these exceptions when compiling with no optimization
1582 if Configurable_Run_Time_On_Target
1583 and then (Restriction_Active
(No_Exception_Handlers
)
1585 Restriction_Active
(No_Exception_Propagation
))
1588 Make_Procedure_Call_Statement
(Loc
,
1589 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1590 Parameter_Associations
=> New_List
(
1591 New_Occurrence_Of
(RTE
(RE_Null_Id
), Loc
),
1595 Make_Procedure_Call_Statement
(Loc
,
1596 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1597 Parameter_Associations
=> New_List
(
1598 Make_Attribute_Reference
(Loc
,
1600 Attribute_Name
=> Name_Identity
),
1608 -- Remaining processing is for the case where no string expression is
1611 -- Don't expand a raise statement that does not come from source if we
1612 -- have already had configurable run-time violations, since most likely
1613 -- it will be junk cascaded nonsense.
1615 if Configurable_Run_Time_Violations
> 0
1616 and then not Comes_From_Source
(N
)
1621 -- Convert explicit raise of Program_Error, Constraint_Error, and
1622 -- Storage_Error into the corresponding raise (in High_Integrity_Mode
1623 -- all other raises will get normal expansion and be disallowed,
1624 -- but this is also faster in all modes). Propagate Comes_From_Source
1625 -- flag to the new node.
1627 if Present
(Name
(N
)) and then Nkind
(Name
(N
)) = N_Identifier
then
1628 Src
:= Comes_From_Source
(N
);
1630 if Entity
(Name
(N
)) = Standard_Constraint_Error
then
1632 Make_Raise_Constraint_Error
(Loc
, Reason
=> CE_Explicit_Raise
));
1633 Set_Comes_From_Source
(N
, Src
);
1637 elsif Entity
(Name
(N
)) = Standard_Program_Error
then
1639 Make_Raise_Program_Error
(Loc
, Reason
=> PE_Explicit_Raise
));
1640 Set_Comes_From_Source
(N
, Src
);
1644 elsif Entity
(Name
(N
)) = Standard_Storage_Error
then
1646 Make_Raise_Storage_Error
(Loc
, Reason
=> SE_Explicit_Raise
));
1647 Set_Comes_From_Source
(N
, Src
);
1653 -- Case of name present, in this case we expand raise name to
1655 -- Raise_Exception (name'Identity, location_string);
1657 -- where location_string identifies the file/line of the raise
1659 if Present
(Name
(N
)) then
1661 Id
: Entity_Id
:= Entity
(Name
(N
));
1662 Buf
: Bounded_String
;
1665 Build_Location_String
(Buf
, Loc
);
1667 -- If the exception is a renaming, use the exception that it
1668 -- renames (which might be a predefined exception, e.g.).
1670 if Present
(Renamed_Object
(Id
)) then
1671 Id
:= Renamed_Object
(Id
);
1674 -- Build a C-compatible string in case of no exception handlers,
1675 -- since this is what the last chance handler is expecting.
1677 if No_Exception_Handlers_Set
then
1679 -- Generate an empty message if configuration pragma
1680 -- Suppress_Exception_Locations is set for this unit.
1682 if Opt
.Exception_Locations_Suppressed
then
1686 Append
(Buf
, ASCII
.NUL
);
1689 if Opt
.Exception_Locations_Suppressed
then
1693 Str
:= String_From_Name_Buffer
(Buf
);
1695 -- Convert raise to call to the Raise_Exception routine
1698 Make_Procedure_Call_Statement
(Loc
,
1700 New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1701 Parameter_Associations
=> New_List
(
1702 Make_Attribute_Reference
(Loc
,
1704 Attribute_Name
=> Name_Identity
),
1705 Make_String_Literal
(Loc
, Strval
=> Str
))));
1708 -- Case of no name present (reraise). We rewrite the raise to:
1710 -- Reraise_Occurrence_Always (EO);
1712 -- where EO is the current exception occurrence. If the current handler
1713 -- does not have a choice parameter specification, then we provide one.
1716 -- Bypass expansion to a run-time call when back-end exception
1717 -- handling is active, unless the target is CodePeer or GNATprove.
1718 -- In CodePeer, raising an exception is treated as an error, while in
1719 -- GNATprove all code with exceptions falls outside the subset of
1720 -- code which can be formally analyzed.
1722 if not CodePeer_Mode
1723 and then Back_End_Exceptions
1728 -- Find innermost enclosing exception handler (there must be one,
1729 -- since the semantics has already verified that this raise statement
1730 -- is valid, and a raise with no arguments is only permitted in the
1731 -- context of an exception handler.
1733 Ehand
:= Parent
(N
);
1734 while Nkind
(Ehand
) /= N_Exception_Handler
loop
1735 Ehand
:= Parent
(Ehand
);
1738 -- Make exception choice parameter if none present. Note that we do
1739 -- not need to put the entity on the entity chain, since no one will
1740 -- be referencing this entity by normal visibility methods.
1742 if No
(Choice_Parameter
(Ehand
)) then
1743 E
:= Make_Temporary
(Loc
, 'E');
1744 Set_Choice_Parameter
(Ehand
, E
);
1745 Set_Ekind
(E
, E_Variable
);
1746 Set_Etype
(E
, RTE
(RE_Exception_Occurrence
));
1747 Set_Scope
(E
, Current_Scope
);
1750 -- Now rewrite the raise as a call to Reraise. A special case arises
1751 -- if this raise statement occurs in the context of a handler for
1752 -- all others (i.e. an at end handler). in this case we avoid
1753 -- the call to defer abort, cleanup routines are expected to be
1754 -- called in this case with aborts deferred.
1757 Ech
: constant Node_Id
:= First
(Exception_Choices
(Ehand
));
1761 if Nkind
(Ech
) = N_Others_Choice
1762 and then All_Others
(Ech
)
1764 Ent
:= RTE
(RE_Reraise_Occurrence_No_Defer
);
1766 Ent
:= RTE
(RE_Reraise_Occurrence_Always
);
1770 Make_Procedure_Call_Statement
(Loc
,
1771 Name
=> New_Occurrence_Of
(Ent
, Loc
),
1772 Parameter_Associations
=> New_List
(
1773 New_Occurrence_Of
(Choice_Parameter
(Ehand
), Loc
))));
1778 end Expand_N_Raise_Statement
;
1780 ----------------------------------
1781 -- Expand_N_Raise_Storage_Error --
1782 ----------------------------------
1784 procedure Expand_N_Raise_Storage_Error
(N
: Node_Id
) is
1786 -- We adjust the condition to deal with the C/Fortran boolean case. This
1787 -- may well not be necessary, as all such conditions are generated by
1788 -- the expander and probably are all standard boolean, but who knows
1789 -- what strange optimization in future may require this adjustment.
1791 Adjust_Condition
(Condition
(N
));
1793 -- Now deal with possible local raise handling
1795 Possible_Local_Raise
(N
, Standard_Storage_Error
);
1796 end Expand_N_Raise_Storage_Error
;
1798 --------------------------
1799 -- Possible_Local_Raise --
1800 --------------------------
1802 procedure Possible_Local_Raise
(N
: Node_Id
; E
: Entity_Id
) is
1804 -- Nothing to do if local raise optimization not active
1806 if not Debug_Flag_Dot_G
1807 and then not Restriction_Active
(No_Exception_Propagation
)
1812 -- Nothing to do if original node was an explicit raise, because in
1813 -- that case, we already generated the required warning for the raise.
1815 if Nkind
(Original_Node
(N
)) = N_Raise_Statement
then
1819 -- Otherwise see if we have a local handler for the exception
1822 H
: constant Node_Id
:= Find_Local_Handler
(E
, N
);
1825 -- If so, mark that it has a local raise
1828 Set_Has_Local_Raise
(H
, True);
1830 -- Otherwise, if the No_Exception_Propagation restriction is active
1831 -- and the warning is enabled, generate the appropriate warnings.
1833 elsif Warn_On_Non_Local_Exception
1834 and then Restriction_Active
(No_Exception_Propagation
)
1836 Warn_No_Exception_Propagation_Active
(N
);
1838 if Configurable_Run_Time_Mode
then
1840 ("\?X?& may call Last_Chance_Handler", N
, E
);
1843 ("\?X?& may result in unhandled exception", N
, E
);
1847 end Possible_Local_Raise
;
1849 ------------------------
1850 -- Find_Local_Handler --
1851 ------------------------
1853 function Find_Local_Handler
1855 Nod
: Node_Id
) return Node_Id
1862 SSE
: Scope_Stack_Entry
renames Scope_Stack
.Table
(Scope_Stack
.Last
);
1863 -- This is used to test for wrapped actions below
1866 EHandle
: Entity_Id
;
1867 -- The entity Id's for the exception we are raising and handling, using
1868 -- the renamed exception if a Renamed_Entity is present.
1871 -- Never any local handler if all handlers removed
1873 if Debug_Flag_Dot_X
then
1877 -- Get the exception we are raising, allowing for renaming
1879 ERaise
:= Get_Renamed_Entity
(Ename
);
1881 -- We need to check if the node we are looking at is contained in
1884 -- Loop to search up the tree
1890 -- If we get to the top of the tree, or to a subprogram, task, entry,
1891 -- protected body, or accept statement without having found a
1892 -- matching handler, then there is no local handler.
1895 or else Nkind
(P
) = N_Subprogram_Body
1896 or else Nkind
(P
) = N_Task_Body
1897 or else Nkind
(P
) = N_Protected_Body
1898 or else Nkind
(P
) = N_Entry_Body
1899 or else Nkind
(P
) = N_Accept_Statement
1903 -- Test for handled sequence of statements with at least one
1904 -- exception handler which might be the one we are looking for.
1906 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
1907 and then Present
(Exception_Handlers
(P
))
1909 -- Before we proceed we need to check if the node N is covered
1910 -- by the statement part of P rather than one of its exception
1911 -- handlers (an exception handler obviously does not cover its
1914 -- This test is more delicate than might be thought. It is not
1915 -- just a matter of checking the Statements (P), because the node
1916 -- might be waiting to be wrapped in a transient scope, in which
1917 -- case it will end up in the block statements, even though it
1918 -- is not there now.
1920 if Is_List_Member
(N
) then
1922 LCN
: constant List_Id
:= List_Containing
(N
);
1925 if LCN
= Statements
(P
)
1927 LCN
= SSE
.Actions_To_Be_Wrapped
(Before
)
1929 LCN
= SSE
.Actions_To_Be_Wrapped
(After
)
1931 LCN
= SSE
.Actions_To_Be_Wrapped
(Cleanup
)
1933 -- Loop through exception handlers
1935 H
:= First
(Exception_Handlers
(P
));
1936 while Present
(H
) loop
1938 -- Guard against other constructs appearing in the
1939 -- list of exception handlers.
1941 if Nkind
(H
) = N_Exception_Handler
then
1943 -- Loop through choices in one handler
1945 C
:= First
(Exception_Choices
(H
));
1946 while Present
(C
) loop
1948 -- Deal with others case
1950 if Nkind
(C
) = N_Others_Choice
then
1952 -- Matching others handler, but we need
1953 -- to ensure there is no choice parameter.
1954 -- If there is, then we don't have a local
1955 -- handler after all (since we do not allow
1956 -- choice parameters for local handlers).
1958 if No
(Choice_Parameter
(H
)) then
1964 -- If not others must be entity name
1966 elsif Nkind
(C
) /= N_Others_Choice
then
1967 pragma Assert
(Is_Entity_Name
(C
));
1968 pragma Assert
(Present
(Entity
(C
)));
1970 -- Get exception being handled, dealing with
1973 EHandle
:= Get_Renamed_Entity
(Entity
(C
));
1975 -- If match, then check choice parameter
1977 if ERaise
= EHandle
then
1978 if No
(Choice_Parameter
(H
)) then
1999 end Find_Local_Handler
;
2001 ---------------------------------
2002 -- Get_Local_Raise_Call_Entity --
2003 ---------------------------------
2005 -- Note: this is primarily provided for use by the back end in generating
2006 -- calls to Local_Raise. But it would be too late in the back end to call
2007 -- RTE if this actually caused a load/analyze of the unit. So what we do
2008 -- is to ensure there is a dummy call to this function during front end
2009 -- processing so that the unit gets loaded then, and not later.
2011 Local_Raise_Call_Entity
: Entity_Id
;
2012 Local_Raise_Call_Entity_Set
: Boolean := False;
2014 function Get_Local_Raise_Call_Entity
return Entity_Id
is
2016 if not Local_Raise_Call_Entity_Set
then
2017 Local_Raise_Call_Entity_Set
:= True;
2019 if RTE_Available
(RE_Local_Raise
) then
2020 Local_Raise_Call_Entity
:= RTE
(RE_Local_Raise
);
2022 Local_Raise_Call_Entity
:= Empty
;
2026 return Local_Raise_Call_Entity
;
2027 end Get_Local_Raise_Call_Entity
;
2029 -----------------------------
2030 -- Get_RT_Exception_Entity --
2031 -----------------------------
2033 function Get_RT_Exception_Entity
(R
: RT_Exception_Code
) return Entity_Id
is
2036 when CE_Reason
=> return Standard_Constraint_Error
;
2037 when PE_Reason
=> return Standard_Program_Error
;
2038 when SE_Reason
=> return Standard_Storage_Error
;
2040 end Get_RT_Exception_Entity
;
2042 ---------------------------
2043 -- Get_RT_Exception_Name --
2044 ---------------------------
2046 procedure Get_RT_Exception_Name
(Code
: RT_Exception_Code
) is
2049 when CE_Access_Check_Failed
=>
2050 Add_Str_To_Name_Buffer
("CE_Access_Check");
2051 when CE_Access_Parameter_Is_Null
=>
2052 Add_Str_To_Name_Buffer
("CE_Null_Access_Parameter");
2053 when CE_Discriminant_Check_Failed
=>
2054 Add_Str_To_Name_Buffer
("CE_Discriminant_Check");
2055 when CE_Divide_By_Zero
=>
2056 Add_Str_To_Name_Buffer
("CE_Divide_By_Zero");
2057 when CE_Explicit_Raise
=>
2058 Add_Str_To_Name_Buffer
("CE_Explicit_Raise");
2059 when CE_Index_Check_Failed
=>
2060 Add_Str_To_Name_Buffer
("CE_Index_Check");
2061 when CE_Invalid_Data
=>
2062 Add_Str_To_Name_Buffer
("CE_Invalid_Data");
2063 when CE_Length_Check_Failed
=>
2064 Add_Str_To_Name_Buffer
("CE_Length_Check");
2065 when CE_Null_Exception_Id
=>
2066 Add_Str_To_Name_Buffer
("CE_Null_Exception_Id");
2067 when CE_Null_Not_Allowed
=>
2068 Add_Str_To_Name_Buffer
("CE_Null_Not_Allowed");
2069 when CE_Overflow_Check_Failed
=>
2070 Add_Str_To_Name_Buffer
("CE_Overflow_Check");
2071 when CE_Partition_Check_Failed
=>
2072 Add_Str_To_Name_Buffer
("CE_Partition_Check");
2073 when CE_Range_Check_Failed
=>
2074 Add_Str_To_Name_Buffer
("CE_Range_Check");
2075 when CE_Tag_Check_Failed
=>
2076 Add_Str_To_Name_Buffer
("CE_Tag_Check");
2078 when PE_Access_Before_Elaboration
=>
2079 Add_Str_To_Name_Buffer
("PE_Access_Before_Elaboration");
2080 when PE_Accessibility_Check_Failed
=>
2081 Add_Str_To_Name_Buffer
("PE_Accessibility_Check");
2082 when PE_Address_Of_Intrinsic
=>
2083 Add_Str_To_Name_Buffer
("PE_Address_Of_Intrinsic");
2084 when PE_Aliased_Parameters
=>
2085 Add_Str_To_Name_Buffer
("PE_Aliased_Parameters");
2086 when PE_All_Guards_Closed
=>
2087 Add_Str_To_Name_Buffer
("PE_All_Guards_Closed");
2088 when PE_Bad_Predicated_Generic_Type
=>
2089 Add_Str_To_Name_Buffer
("PE_Bad_Predicated_Generic_Type");
2090 when PE_Current_Task_In_Entry_Body
=>
2091 Add_Str_To_Name_Buffer
("PE_Current_Task_In_Entry_Body");
2092 when PE_Duplicated_Entry_Address
=>
2093 Add_Str_To_Name_Buffer
("PE_Duplicated_Entry_Address");
2094 when PE_Explicit_Raise
=>
2095 Add_Str_To_Name_Buffer
("PE_Explicit_Raise");
2096 when PE_Finalize_Raised_Exception
=>
2097 Add_Str_To_Name_Buffer
("PE_Finalize_Raised_Exception");
2098 when PE_Implicit_Return
=>
2099 Add_Str_To_Name_Buffer
("PE_Implicit_Return");
2100 when PE_Misaligned_Address_Value
=>
2101 Add_Str_To_Name_Buffer
("PE_Misaligned_Address_Value");
2102 when PE_Missing_Return
=>
2103 Add_Str_To_Name_Buffer
("PE_Missing_Return");
2104 when PE_Non_Transportable_Actual
=>
2105 Add_Str_To_Name_Buffer
("PE_Non_Transportable_Actual");
2106 when PE_Overlaid_Controlled_Object
=>
2107 Add_Str_To_Name_Buffer
("PE_Overlaid_Controlled_Object");
2108 when PE_Potentially_Blocking_Operation
=>
2109 Add_Str_To_Name_Buffer
("PE_Potentially_Blocking_Operation");
2110 when PE_Stream_Operation_Not_Allowed
=>
2111 Add_Str_To_Name_Buffer
("PE_Stream_Operation_Not_Allowed");
2112 when PE_Stubbed_Subprogram_Called
=>
2113 Add_Str_To_Name_Buffer
("PE_Stubbed_Subprogram_Called");
2114 when PE_Unchecked_Union_Restriction
=>
2115 Add_Str_To_Name_Buffer
("PE_Unchecked_Union_Restriction");
2117 when SE_Empty_Storage_Pool
=>
2118 Add_Str_To_Name_Buffer
("SE_Empty_Storage_Pool");
2119 when SE_Explicit_Raise
=>
2120 Add_Str_To_Name_Buffer
("SE_Explicit_Raise");
2121 when SE_Infinite_Recursion
=>
2122 Add_Str_To_Name_Buffer
("SE_Infinite_Recursion");
2123 when SE_Object_Too_Large
=>
2124 Add_Str_To_Name_Buffer
("SE_Object_Too_Large");
2126 end Get_RT_Exception_Name
;
2128 ----------------------------
2129 -- Warn_If_No_Propagation --
2130 ----------------------------
2132 procedure Warn_If_No_Propagation
(N
: Node_Id
) is
2134 if Restriction_Check_Required
(No_Exception_Propagation
)
2135 and then Warn_On_Non_Local_Exception
2137 Warn_No_Exception_Propagation_Active
(N
);
2139 if Configurable_Run_Time_Mode
then
2141 ("\?X?Last_Chance_Handler will be called on exception", N
);
2144 ("\?X?execution may raise unhandled exception", N
);
2147 end Warn_If_No_Propagation
;
2149 ------------------------------------------
2150 -- Warn_No_Exception_Propagation_Active --
2151 ------------------------------------------
2153 procedure Warn_No_Exception_Propagation_Active
(N
: Node_Id
) is
2156 ("?X?pragma Restrictions (No_Exception_Propagation) in effect", N
);
2157 end Warn_No_Exception_Propagation_Active
;