1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2023, 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 Einfo
.Entities
; use Einfo
.Entities
;
30 with Einfo
.Utils
; use Einfo
.Utils
;
31 with Elists
; use Elists
;
32 with Errout
; use Errout
;
33 with Exp_Ch7
; use Exp_Ch7
;
34 with Exp_Intr
; use Exp_Intr
;
35 with Exp_Util
; use Exp_Util
;
36 with Namet
; use Namet
;
37 with Nlists
; use Nlists
;
38 with Nmake
; use Nmake
;
40 with Restrict
; use Restrict
;
41 with Rident
; use Rident
;
42 with Rtsfind
; use Rtsfind
;
44 with Sem_Res
; use Sem_Res
;
45 with Sem_Util
; use Sem_Util
;
46 with Sinfo
; use Sinfo
;
47 with Sinfo
.Nodes
; use Sinfo
.Nodes
;
48 with Sinfo
.Utils
; use Sinfo
.Utils
;
49 with Sinput
; use Sinput
;
50 with Snames
; use Snames
;
51 with Stand
; use Stand
;
52 with Stringt
; use Stringt
;
53 with Targparm
; use Targparm
;
54 with Tbuild
; use Tbuild
;
55 with Uintp
; use Uintp
;
56 with Warnsw
; use Warnsw
;
58 package body Exp_Ch11
is
60 -----------------------
61 -- Local Subprograms --
62 -----------------------
64 procedure Warn_No_Exception_Propagation_Active
(N
: Node_Id
);
65 -- Generates warning that pragma Restrictions (No_Exception_Propagation)
66 -- is in effect. Caller then generates appropriate continuation message.
67 -- N is the node on which the warning is placed.
69 procedure Warn_If_No_Propagation
(N
: Node_Id
);
70 -- Called for an exception raise that is not a local raise (and thus cannot
71 -- be optimized to a goto). Issues warning if No_Exception_Propagation
72 -- restriction is set. N is the node for the raise or equivalent call.
74 ---------------------------
75 -- Expand_At_End_Handler --
76 ---------------------------
78 -- For a handled statement sequence that has a cleanup (At_End_Proc
79 -- field set), perform any needed expansion.
81 -- Do nothing by default. We used to perform a special expansion for
82 -- front-end SJLJ, and we may want to customize this processing in
83 -- the future for new back-ends.
85 procedure Expand_At_End_Handler
(HSS
: Node_Id
; Blk_Id
: Entity_Id
) is
86 pragma Unreferenced
(Blk_Id
);
88 pragma Assert
(Present
(Entity
(At_End_Proc
(HSS
))));
89 end Expand_At_End_Handler
;
91 -------------------------------
92 -- Expand_Exception_Handlers --
93 -------------------------------
95 procedure Expand_Exception_Handlers
(HSS
: Node_Id
) is
96 Handlrs
: constant List_Id
:= Exception_Handlers
(HSS
);
97 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
100 Next_Handler
: Node_Id
;
102 procedure Expand_Local_Exception_Handlers
;
103 -- This procedure handles the expansion of exception handlers for the
104 -- optimization of local raise statements into goto statements.
106 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
);
107 -- Raise_S is a raise statement (possibly expanded, and possibly of the
108 -- form of a Raise_xxx_Error node with a condition. This procedure is
109 -- called to replace the raise action with the (already analyzed) goto
110 -- statement passed as Goto_L1. This procedure also takes care of the
111 -- requirement of inserting a Local_Raise call where possible.
113 -------------------------------------
114 -- Expand_Local_Exception_Handlers --
115 -------------------------------------
117 -- There are two cases for this transformation. First the case of
118 -- explicit raise statements. For this case, the transformation we do
119 -- looks like this. Right now we have for example (where L1, L2 are
124 -- raise_exception (excep1'identity); -- was raise excep1
126 -- raise_exception (excep2'identity); -- was raise excep2
135 -- This gets transformed into:
138 -- L1 : label; -- marked Exception_Junk
139 -- L2 : label; -- marked Exception_Junk
140 -- L3 : label; -- marked Exception_Junk
142 -- begin -- marked Exception_Junk
144 -- local_raise (excep1'address); -- was raise excep1
147 -- local_raise (excep2'address); -- was raise excep2
157 -- goto L3; -- skip handler if no raise, marked Exception_Junk
159 -- <<L1>> -- local excep target label, marked Exception_Junk
160 -- begin -- marked Exception_Junk
163 -- goto L3; -- marked Exception_Junk
165 -- <<L2>> -- marked Exception_Junk
166 -- begin -- marked Exception_Junk
169 -- goto L3; -- marked Exception_Junk
170 -- <<L3>> -- marked Exception_Junk
173 -- Note: the reason we wrap the original statement sequence in an
174 -- inner block is that there may be raise statements within the
175 -- sequence of statements in the handlers, and we must ensure that
176 -- these are properly handled, and in particular, such raise statements
177 -- must not reenter the same exception handlers.
179 -- If the restriction No_Exception_Propagation is in effect, then we
180 -- can omit the exception handlers.
183 -- L1 : label; -- marked Exception_Junk
184 -- L2 : label; -- marked Exception_Junk
185 -- L3 : label; -- marked Exception_Junk
187 -- begin -- marked Exception_Junk
189 -- local_raise (excep1'address); -- was raise excep1
192 -- local_raise (excep2'address); -- was raise excep2
197 -- goto L3; -- skip handler if no raise, marked Exception_Junk
199 -- <<L1>> -- local excep target label, marked Exception_Junk
200 -- begin -- marked Exception_Junk
203 -- goto L3; -- marked Exception_Junk
205 -- <<L2>> -- marked Exception_Junk
206 -- begin -- marked Exception_Junk
210 -- <<L3>> -- marked Exception_Junk
213 -- The second case is for exceptions generated by the back end in one
214 -- of three situations:
216 -- 1. Front end generates N_Raise_xxx_Error node
217 -- 2. Front end sets Do_xxx_Check flag in subexpression node
218 -- 3. Back end detects a situation where an exception is appropriate
220 -- In all these cases, the current processing in gigi is to generate a
221 -- call to the appropriate Rcheck_xx routine (where xx encodes both the
222 -- exception message and the exception to be raised, Constraint_Error,
223 -- Program_Error, or Storage_Error.
225 -- We could handle some subcases of 1 using the same front end expansion
226 -- into gotos, but even for case 1, we can't handle all cases, since
227 -- generating gotos in the middle of expressions is not possible (it's
228 -- possible at the gigi/gcc level, but not at the level of the GNAT
231 -- In any case, it seems easier to have a scheme which handles all three
232 -- cases in a uniform manner. So here is how we proceed in this case.
234 -- This procedure detects all handlers for these three exceptions,
235 -- Constraint_Error, Program_Error and Storage_Error (including WHEN
236 -- OTHERS handlers that cover one or more of these cases).
238 -- If the handler meets the requirements for being the target of a local
239 -- raise, then the front end does the expansion described previously,
240 -- creating a label to be used as a goto target to raise the exception.
241 -- However, no attempt is made in the front end to convert any related
242 -- raise statements into gotos, e.g. all N_Raise_xxx_Error nodes are
243 -- left unchanged and passed to the back end.
245 -- Instead, the front end generates three nodes
247 -- N_Push_Constraint_Error_Label
248 -- N_Push_Program_Error_Label
249 -- N_Push_Storage_Error_Label
251 -- The Push node is generated at the start of the statements
252 -- covered by the handler, and has as a parameter the label to be
253 -- used as the raise target.
255 -- N_Pop_Constraint_Error_Label
256 -- N_Pop_Program_Error_Label
257 -- N_Pop_Storage_Error_Label
259 -- The Pop node is generated at the end of the covered statements
260 -- and undoes the effect of the preceding corresponding Push node.
262 -- In the case where the handler does NOT meet the requirements, the
263 -- front end will still generate the Push and Pop nodes, but the label
264 -- field in the Push node will be empty signifying that for this region
265 -- of code, no optimization is possible.
267 -- These Push/Pop nodes are inhibited if No_Exception_Handlers is set
268 -- since they are useless in this case, and in CodePeer mode, where
269 -- they serve no purpose and can intefere with the analysis.
271 -- The back end must maintain three stacks, one for each exception case,
272 -- the Push node pushes an entry onto the corresponding stack, and Pop
273 -- node pops off the entry. Then instead of calling Rcheck_nn, if the
274 -- corresponding top stack entry has an non-empty label, a goto is
275 -- generated. This goto should be preceded by a call to Local_Raise as
278 -- An example of this transformation is as follows, given:
281 -- A : Integer range 1 .. 10;
285 -- when Constraint_Error =>
289 -- gets transformed to:
292 -- A : Integer range 1 .. 10;
299 -- %push_constraint_error_label (L1)
300 -- R1b : constant long_long_integer := long_long_integer?(b) +
301 -- long_long_integer?(c);
302 -- [constraint_error when
303 -- not (R1b in -16#8000_0000# .. 16#7FFF_FFFF#)
304 -- "overflow check failed"]
305 -- a := integer?(R1b);
306 -- %pop_constraint_error_Label
310 -- when constraint_error =>
314 -- goto L2; -- skip handler when exception not raised
315 -- <<L1>> -- target label for local exception
320 -- Note: the generated labels and goto statements all have the flag
321 -- Exception_Junk set True, so that Sem_Ch6.Check_Returns will ignore
322 -- this generated exception stuff when checking for missing return
323 -- statements (see circuitry in Check_Statement_Sequence).
325 -- Note: All of the processing described above occurs only if
326 -- restriction No_Exception_Propagation applies or debug flag .g is
329 CE_Locally_Handled
: Boolean := False;
330 SE_Locally_Handled
: Boolean := False;
331 PE_Locally_Handled
: Boolean := False;
332 -- These three flags indicate whether a handler for the corresponding
333 -- exception (CE=Constraint_Error, SE=Storage_Error, PE=Program_Error)
334 -- is present. If so the switch is set to True, the Exception_Label
335 -- field of the corresponding handler is set, and appropriate Push
336 -- and Pop nodes are inserted into the code.
338 Local_Expansion_Required
: Boolean := False;
339 -- Set True if we have at least one handler requiring local raise
340 -- expansion as described above.
342 procedure Expand_Local_Exception_Handlers
is
343 procedure Add_Exception_Label
(H
: Node_Id
);
344 -- H is an exception handler. First check for an Exception_Label
345 -- already allocated for H. If none, allocate one, set the field in
346 -- the handler node, add the label declaration, and set the flag
347 -- Local_Expansion_Required. Note: if Local_Raise_Not_OK is set
348 -- the call has no effect and Exception_Label is left empty.
350 procedure Add_Label_Declaration
(L
: Entity_Id
);
351 -- Add an implicit declaration of the given label to the declaration
352 -- list in the parent of the current sequence of handled statements.
355 Exc_Locally_Handled
: in out Boolean;
356 -- Flag indicating whether a local handler for this exception
357 -- has already been generated.
359 with function Make_Push_Label
(Loc
: Source_Ptr
) return Node_Id
;
360 -- Function to create a Push_xxx_Label node
362 with function Make_Pop_Label
(Loc
: Source_Ptr
) return Node_Id
;
363 -- Function to create a Pop_xxx_Label node
365 procedure Generate_Push_Pop
(H
: Node_Id
);
366 -- Common code for Generate_Push_Pop_xxx below, used to generate an
367 -- exception label and Push/Pop nodes for Constraint_Error,
368 -- Program_Error, or Storage_Error.
370 -------------------------
371 -- Add_Exception_Label --
372 -------------------------
374 procedure Add_Exception_Label
(H
: Node_Id
) is
376 if No
(Exception_Label
(H
))
377 and then not Local_Raise_Not_OK
(H
)
378 and then not Special_Exception_Package_Used
380 Local_Expansion_Required
:= True;
383 L
: constant Entity_Id
:= Make_Temporary
(Sloc
(H
), 'L');
385 Set_Exception_Label
(H
, L
);
386 Add_Label_Declaration
(L
);
389 end Add_Exception_Label
;
391 ---------------------------
392 -- Add_Label_Declaration --
393 ---------------------------
395 procedure Add_Label_Declaration
(L
: Entity_Id
) is
396 P
: constant Node_Id
:= Parent
(HSS
);
398 Decl_L
: constant Node_Id
:=
399 Make_Implicit_Label_Declaration
(Loc
,
400 Defining_Identifier
=> L
);
403 if Declarations
(P
) = No_List
then
404 Set_Declarations
(P
, Empty_List
);
407 Append
(Decl_L
, Declarations
(P
));
409 end Add_Label_Declaration
;
411 -----------------------
412 -- Generate_Push_Pop --
413 -----------------------
415 procedure Generate_Push_Pop
(H
: Node_Id
) is
417 if Restriction_Active
(No_Exception_Handlers
)
418 or else CodePeer_Mode
423 if Exc_Locally_Handled
then
426 Exc_Locally_Handled
:= True;
429 Add_Exception_Label
(H
);
432 F
: constant Node_Id
:= First
(Statements
(HSS
));
433 L
: constant Node_Id
:= Last
(Statements
(HSS
));
435 Push
: constant Node_Id
:= Make_Push_Label
(Sloc
(F
));
436 Pop
: constant Node_Id
:= Make_Pop_Label
(Sloc
(L
));
439 -- We make sure that a call to Get_Local_Raise_Call_Entity is
440 -- made during front end processing, so that when we need it
441 -- in the back end, it will already be available and loaded.
443 Discard_Node
(Get_Local_Raise_Call_Entity
);
445 -- Prepare and insert Push and Pop nodes
447 Set_Exception_Label
(Push
, Exception_Label
(H
));
448 Insert_Before
(F
, Push
);
451 Insert_After
(L
, Pop
);
454 end Generate_Push_Pop
;
456 -- Local declarations
458 Loc
: constant Source_Ptr
:= Sloc
(HSS
);
459 Stmts
: List_Id
:= No_List
;
463 procedure Generate_Push_Pop_For_Constraint_Error
is
464 new Generate_Push_Pop
465 (Exc_Locally_Handled
=> CE_Locally_Handled
,
466 Make_Push_Label
=> Make_Push_Constraint_Error_Label
,
467 Make_Pop_Label
=> Make_Pop_Constraint_Error_Label
);
468 -- If no Push/Pop has been generated for CE yet, then set the flag
469 -- CE_Locally_Handled, allocate an Exception_Label for handler H (if
470 -- not already done), and generate Push/Pop nodes for the exception
471 -- label at the start and end of the statements of HSS.
473 procedure Generate_Push_Pop_For_Program_Error
is
474 new Generate_Push_Pop
475 (Exc_Locally_Handled
=> PE_Locally_Handled
,
476 Make_Push_Label
=> Make_Push_Program_Error_Label
,
477 Make_Pop_Label
=> Make_Pop_Program_Error_Label
);
478 -- If no Push/Pop has been generated for PE yet, then set the flag
479 -- PE_Locally_Handled, allocate an Exception_Label for handler H (if
480 -- not already done), and generate Push/Pop nodes for the exception
481 -- label at the start and end of the statements of HSS.
483 procedure Generate_Push_Pop_For_Storage_Error
is
484 new Generate_Push_Pop
485 (Exc_Locally_Handled
=> SE_Locally_Handled
,
486 Make_Push_Label
=> Make_Push_Storage_Error_Label
,
487 Make_Pop_Label
=> Make_Pop_Storage_Error_Label
);
488 -- If no Push/Pop has been generated for SE yet, then set the flag
489 -- SE_Locally_Handled, allocate an Exception_Label for handler H (if
490 -- not already done), and generate Push/Pop nodes for the exception
491 -- label at the start and end of the statements of HSS.
493 -- Start of processing for Expand_Local_Exception_Handlers
496 -- No processing if all exception handlers will get removed
498 if Debug_Flag_Dot_X
then
502 -- See for each handler if we have any local raises to expand
504 Handler
:= First_Non_Pragma
(Handlrs
);
505 while Present
(Handler
) loop
507 -- Note, we do not test Local_Raise_Not_OK here, because in the
508 -- case of Push/Pop generation we want to generate push with a
509 -- null label. The Add_Exception_Label routine has no effect if
510 -- Local_Raise_Not_OK is set, so this works as required.
512 if Present
(Local_Raise_Statements
(Handler
)) then
513 Add_Exception_Label
(Handler
);
516 -- If we are doing local raise to goto optimization (restriction
517 -- No_Exception_Propagation set or debug flag .g set), then check
518 -- to see if handler handles CE, PE, SE and if so generate the
519 -- appropriate push/pop sequence for the back end.
522 or else Restriction_Active
(No_Exception_Propagation
))
523 and then Has_Local_Raise
(Handler
)
525 Choice
:= First
(Exception_Choices
(Handler
));
526 while Present
(Choice
) loop
527 if Nkind
(Choice
) = N_Others_Choice
528 and then not All_Others
(Choice
)
530 Generate_Push_Pop_For_Constraint_Error
(Handler
);
531 Generate_Push_Pop_For_Program_Error
(Handler
);
532 Generate_Push_Pop_For_Storage_Error
(Handler
);
534 elsif Is_Entity_Name
(Choice
) then
535 Excep
:= Get_Renamed_Entity
(Entity
(Choice
));
537 if Excep
= Standard_Constraint_Error
then
538 Generate_Push_Pop_For_Constraint_Error
(Handler
);
539 elsif Excep
= Standard_Program_Error
then
540 Generate_Push_Pop_For_Program_Error
(Handler
);
541 elsif Excep
= Standard_Storage_Error
then
542 Generate_Push_Pop_For_Storage_Error
(Handler
);
550 Next_Non_Pragma
(Handler
);
553 -- Nothing to do if no handlers requiring the goto transformation
555 if not (Local_Expansion_Required
) then
559 -- Prepare to do the transformation
562 -- L3 is the label to exit the HSS
564 L3_Dent
: constant Entity_Id
:= Make_Temporary
(Loc
, 'L');
566 Labl_L3
: constant Node_Id
:=
568 Identifier
=> New_Occurrence_Of
(L3_Dent
, Loc
));
574 Set_Exception_Junk
(Labl_L3
);
575 Add_Label_Declaration
(L3_Dent
);
577 -- Wrap existing statements and handlers in an inner block
580 Make_Block_Statement
(Loc
,
581 Handled_Statement_Sequence
=> Relocate_Node
(HSS
));
582 Set_Exception_Junk
(Blk_Stm
);
585 Make_Handled_Sequence_Of_Statements
(Loc
,
586 Statements
=> New_List
(Blk_Stm
),
587 End_Label
=> Relocate_Node
(End_Label
(HSS
))));
589 -- Set block statement as analyzed, we don't want to actually call
590 -- Analyze on this block, it would cause a recursion in exception
591 -- handler processing which would mess things up.
593 Set_Analyzed
(Blk_Stm
);
595 -- Now loop through the exception handlers to deal with those that
596 -- are targets of local raise statements.
598 Handler
:= First_Non_Pragma
(Handlrs
);
599 while Present
(Handler
) loop
600 if Present
(Exception_Label
(Handler
)) then
602 -- This handler needs the goto expansion
605 Loc
: constant Source_Ptr
:= Sloc
(Handler
);
607 -- L1 is the start label for this handler
609 L1_Dent
: constant Entity_Id
:= Exception_Label
(Handler
);
611 Labl_L1
: constant Node_Id
:=
614 New_Occurrence_Of
(L1_Dent
, Loc
));
616 -- Jump to L1 to be used as replacement for the original
617 -- handler (used in the case where exception propagation
620 Name_L1
: constant Node_Id
:=
621 New_Occurrence_Of
(L1_Dent
, Loc
);
623 Goto_L1
: constant Node_Id
:=
624 Make_Goto_Statement
(Loc
,
627 -- Jump to L3 to be used at the end of handler
629 Name_L3
: constant Node_Id
:=
630 New_Occurrence_Of
(L3_Dent
, Loc
);
632 Goto_L3
: constant Node_Id
:=
633 Make_Goto_Statement
(Loc
,
636 H_Stmts
: constant List_Id
:= Statements
(Handler
);
639 Set_Exception_Junk
(Labl_L1
);
640 Set_Exception_Junk
(Goto_L3
);
642 -- Note: we do NOT set Exception_Junk in Goto_L1, since
643 -- this is a real transfer of control that we want the
644 -- Sem_Ch6.Check_Returns procedure to recognize properly.
646 -- Replace handler by a goto L1. We can mark this as
647 -- analyzed since it is fully formed, and we don't
648 -- want it going through any further checks. We save
649 -- the last statement location in the goto L1 node for
650 -- the benefit of Sem_Ch6.Check_Returns.
652 Set_Statements
(Handler
, New_List
(Goto_L1
));
653 Set_Analyzed
(Goto_L1
);
654 Set_Etype
(Name_L1
, Standard_Void_Type
);
656 -- Now replace all the raise statements by goto L1
658 if Present
(Local_Raise_Statements
(Handler
)) then
659 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
660 while Present
(Relmt
) loop
662 Raise_S
: constant Node_Id
:= Node
(Relmt
);
663 RLoc
: constant Source_Ptr
:= Sloc
(Raise_S
);
664 Name_L1
: constant Node_Id
:=
665 New_Occurrence_Of
(L1_Dent
, Loc
);
666 Goto_L1
: constant Node_Id
:=
667 Make_Goto_Statement
(RLoc
,
671 -- Replace raise by goto L1
673 Set_Analyzed
(Goto_L1
);
674 Set_Etype
(Name_L1
, Standard_Void_Type
);
675 Replace_Raise_By_Goto
(Raise_S
, Goto_L1
);
682 -- Add a goto L3 at end of statement list in block. The
683 -- first time, this is what skips over the exception
684 -- handlers in the normal case. Subsequent times, it
685 -- terminates the execution of the previous handler code,
686 -- and skips subsequent handlers.
688 Stmts
:= Statements
(HSS
);
690 Insert_After
(Last
(Stmts
), Goto_L3
);
691 Set_Analyzed
(Goto_L3
);
692 Set_Etype
(Name_L3
, Standard_Void_Type
);
694 -- Now we drop the label that marks the handler start,
695 -- followed by the statements of the handler.
697 Set_Etype
(Identifier
(Labl_L1
), Standard_Void_Type
);
699 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L1
);
702 Loc
: constant Source_Ptr
:= Sloc
(First
(H_Stmts
));
703 Blk
: constant Node_Id
:=
704 Make_Block_Statement
(Loc
,
705 Handled_Statement_Sequence
=>
706 Make_Handled_Sequence_Of_Statements
(Loc
,
707 Statements
=> H_Stmts
));
709 Set_Exception_Junk
(Blk
);
710 Insert_After_And_Analyze
(Last
(Stmts
), Blk
);
714 -- Here if we have local raise statements but the handler is
715 -- not suitable for processing with a local raise. In this
716 -- case we have to generate possible diagnostics.
718 elsif Has_Local_Raise
(Handler
)
719 and then Present
(Local_Raise_Statements
(Handler
))
721 Relmt
:= First_Elmt
(Local_Raise_Statements
(Handler
));
722 while Present
(Relmt
) loop
723 Warn_If_No_Propagation
(Node
(Relmt
));
731 -- Only remaining step is to drop the L3 label and we are done
733 Set_Etype
(Identifier
(Labl_L3
), Standard_Void_Type
);
735 -- If we had at least one handler, then we drop the label after
736 -- the last statement of that handler.
738 if Stmts
/= No_List
then
739 Insert_After_And_Analyze
(Last
(Stmts
), Labl_L3
);
741 -- Otherwise we have removed all the handlers (this results from
742 -- use of pragma Restrictions (No_Exception_Propagation), and we
743 -- drop the label at the end of the statements of the HSS.
746 Insert_After_And_Analyze
(Last
(Statements
(HSS
)), Labl_L3
);
751 end Expand_Local_Exception_Handlers
;
753 ---------------------------
754 -- Replace_Raise_By_Goto --
755 ---------------------------
757 procedure Replace_Raise_By_Goto
(Raise_S
: Node_Id
; Goto_L1
: Node_Id
) is
758 Loc
: constant Source_Ptr
:= Sloc
(Raise_S
);
765 -- If we have a null statement, it means that there is no replacement
766 -- needed (typically this results from a suppressed check).
768 if Nkind
(Raise_S
) = N_Null_Statement
then
771 -- Test for Raise_xxx_Error
773 elsif Nkind
(Raise_S
) = N_Raise_Constraint_Error
then
774 Excep
:= Standard_Constraint_Error
;
775 Cond
:= Condition
(Raise_S
);
777 elsif Nkind
(Raise_S
) = N_Raise_Storage_Error
then
778 Excep
:= Standard_Storage_Error
;
779 Cond
:= Condition
(Raise_S
);
781 elsif Nkind
(Raise_S
) = N_Raise_Program_Error
then
782 Excep
:= Standard_Program_Error
;
783 Cond
:= Condition
(Raise_S
);
785 -- The only other possibility is a node that is or used to be a
786 -- simple raise statement. Note that the string expression in the
787 -- original Raise statement is ignored.
790 Orig
:= Original_Node
(Raise_S
);
791 pragma Assert
(Nkind
(Orig
) = N_Raise_Statement
792 and then Present
(Name
(Orig
)));
793 Excep
:= Entity
(Name
(Orig
));
797 -- Here Excep is the exception to raise, and Cond is the condition
798 -- First prepare the call to Local_Raise (excep'address).
800 if RTE_Available
(RE_Local_Raise
) then
802 Make_Procedure_Call_Statement
(Loc
,
803 Name
=> New_Occurrence_Of
(RTE
(RE_Local_Raise
), Loc
),
804 Parameter_Associations
=> New_List
(
805 Unchecked_Convert_To
(RTE
(RE_Address
),
806 Make_Attribute_Reference
(Loc
,
807 Prefix
=> New_Occurrence_Of
(Excep
, Loc
),
808 Attribute_Name
=> Name_Identity
))));
810 -- Use null statement if Local_Raise not available
814 Make_Null_Statement
(Loc
);
817 -- If there is no condition, we rewrite as
820 -- Local_Raise (excep'Identity);
826 Make_Block_Statement
(Loc
,
827 Handled_Statement_Sequence
=>
828 Make_Handled_Sequence_Of_Statements
(Loc
,
829 Statements
=> New_List
(LR
, Goto_L1
))));
830 Set_Exception_Junk
(Raise_S
);
832 -- If there is a condition, we rewrite as
835 -- Local_Raise (excep'Identity);
841 Make_If_Statement
(Loc
,
843 Then_Statements
=> New_List
(LR
, Goto_L1
)));
847 end Replace_Raise_By_Goto
;
849 -- Start of processing for Expand_Exception_Handlers
852 Expand_Local_Exception_Handlers
;
854 -- Loop through handlers
856 Handler
:= First_Non_Pragma
(Handlrs
);
857 Handler_Loop
: while Present
(Handler
) loop
858 Process_Statements_For_Controlled_Objects
(Handler
);
860 Next_Handler
:= Next_Non_Pragma
(Handler
);
862 -- Remove source handler if gnat debug flag .x is set
864 if Debug_Flag_Dot_X
and then Comes_From_Source
(Handler
) then
867 -- Remove handler if no exception propagation, generating a warning
868 -- if a source generated handler was not the target of a local raise.
871 if not Has_Local_Raise
(Handler
)
872 and then Comes_From_Source
(Handler
)
874 Warn_If_No_Local_Raise
(Handler
);
877 if No_Exception_Propagation_Active
then
880 -- Exception handler is active and retained and must be processed
883 -- If an exception occurrence is present, then we must declare
884 -- it and initialize it from the value stored in the TSD
887 -- name : Exception_Occurrence;
889 -- Save_Occurrence (name, Get_Current_Excep.all)
893 -- This expansion is only performed when using CodePeer.
894 -- Gigi will insert a call to initialize the choice parameter.
896 if Present
(Choice_Parameter
(Handler
))
897 and then CodePeer_Mode
900 Cparm
: constant Entity_Id
:= Choice_Parameter
(Handler
);
901 Cloc
: constant Source_Ptr
:= Sloc
(Cparm
);
902 Hloc
: constant Source_Ptr
:= Sloc
(Handler
);
906 -- Note: No_Location used to hide code from the debugger,
907 -- so single stepping doesn't jump back and forth.
910 Make_Procedure_Call_Statement
(No_Location
,
913 (RTE
(RE_Save_Occurrence
), No_Location
),
914 Parameter_Associations
=> New_List
(
915 New_Occurrence_Of
(Cparm
, No_Location
),
916 Make_Explicit_Dereference
(No_Location
,
918 Make_Function_Call
(No_Location
,
920 Make_Explicit_Dereference
(No_Location
,
923 (RTE
(RE_Get_Current_Excep
),
926 Mark_Rewrite_Insertion
(Save
);
927 Prepend
(Save
, Statements
(Handler
));
930 Make_Object_Declaration
(Cloc
,
931 Defining_Identifier
=> Cparm
,
934 (RTE
(RE_Exception_Occurrence
), Cloc
));
935 Set_No_Initialization
(Obj_Decl
, True);
938 Make_Exception_Handler
(Hloc
,
939 Choice_Parameter
=> Empty
,
940 Exception_Choices
=> Exception_Choices
(Handler
),
941 Statements
=> New_List
(
942 Make_Block_Statement
(Hloc
,
943 Declarations
=> New_List
(Obj_Decl
),
944 Handled_Statement_Sequence
=>
945 Make_Handled_Sequence_Of_Statements
(Hloc
,
946 Statements
=> Statements
(Handler
))))));
948 -- Local raise statements can't occur, since exception
949 -- handlers with choice parameters are not allowed when
950 -- No_Exception_Propagation applies, so set attributes
953 Set_Local_Raise_Statements
(Handler
, No_Elist
);
954 Set_Local_Raise_Not_OK
(Handler
);
957 (Statements
(Handler
), Suppress
=> All_Checks
);
963 Handler
:= Next_Handler
;
964 end loop Handler_Loop
;
966 -- If all handlers got removed, then remove the list. Note we cannot
967 -- reference HSS here, since expanding local handlers may have buried
968 -- the handlers in an inner block.
970 if Is_Empty_List
(Handlrs
) then
971 Set_Exception_Handlers
(Parent
(Handlrs
), No_List
);
973 end Expand_Exception_Handlers
;
975 ------------------------------------
976 -- Expand_N_Exception_Declaration --
977 ------------------------------------
980 -- exceptE : constant String := "A.B.EXCEP"; -- static data
981 -- except : exception_data :=
982 -- (Handled_By_Other => False,
984 -- Name_Length => exceptE'Length,
985 -- Full_Name => exceptE'Address,
986 -- HTable_Ptr => null,
987 -- Foreign_Data => null,
988 -- Raise_Hook => null);
990 -- (protecting test only needed if not at library level)
992 -- exceptF : aliased System.Atomic_Operations.Test_And_Set.
993 -- .Test_And_Set_Flag; -- static data
994 -- if not Atomic_Test_And_Set (exceptF) then
995 -- Register_Exception (except'Unrestricted_Access);
998 -- If a No_Tasking restriction is in effect, or if Test_And_Set_Flag
999 -- is unavailable, then use Boolean instead. In that case, we generate:
1001 -- exceptF : Boolean := True; -- static data
1003 -- ExceptF := False;
1004 -- Register_Exception (except'Unrestricted_Access);
1007 procedure Expand_N_Exception_Declaration
(N
: Node_Id
) is
1008 Id
: constant Entity_Id
:= Defining_Identifier
(N
);
1009 Loc
: constant Source_Ptr
:= Sloc
(N
);
1011 procedure Force_Static_Allocation_Of_Referenced_Objects
1012 (Aggregate
: Node_Id
);
1013 -- A specialized solution to one particular case of an ugly problem
1015 -- The given aggregate includes an Unchecked_Conversion as one of the
1016 -- component values. The call to Analyze_And_Resolve below ends up
1017 -- calling Exp_Ch4.Expand_N_Unchecked_Type_Conversion, which may decide
1018 -- to introduce a (constant) temporary and then obtain the component
1019 -- value by evaluating the temporary.
1021 -- In the case of an exception declared within a subprogram (or any
1022 -- other dynamic scope), this is a bad transformation. The exception
1023 -- object is marked as being Statically_Allocated but the temporary is
1024 -- not. If the initial value of a Statically_Allocated declaration
1025 -- references a dynamically allocated object, this prevents static
1026 -- initialization of the object.
1028 -- We cope with this here by marking the temporary Statically_Allocated.
1029 -- It might seem cleaner to generalize this utility and then use it to
1030 -- enforce a rule that the entities referenced in the declaration of any
1031 -- "hoisted" (i.e., Is_Statically_Allocated and not Is_Library_Level)
1032 -- entity must also be either Library_Level or hoisted. It turns out
1033 -- that this would be incompatible with the current treatment of an
1034 -- object which is local to a subprogram, subject to an Export pragma,
1035 -- not subject to an address clause, and whose declaration contains
1036 -- references to other local (non-hoisted) objects (e.g., in the initial
1037 -- value expression).
1039 function Null_String
return String_Id
;
1040 -- Build a null-terminated empty string
1042 ---------------------------------------------------
1043 -- Force_Static_Allocation_Of_Referenced_Objects --
1044 ---------------------------------------------------
1046 procedure Force_Static_Allocation_Of_Referenced_Objects
1047 (Aggregate
: Node_Id
)
1049 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
;
1050 -- If the given node references a dynamically allocated object, then
1051 -- correct the declaration of the object.
1057 function Fixup_Node
(N
: Node_Id
) return Traverse_Result
is
1059 if Nkind
(N
) in N_Has_Entity
1060 and then Present
(Entity
(N
))
1061 and then not Is_Library_Level_Entity
(Entity
(N
))
1063 -- Note: the following test is not needed but it seems cleaner
1064 -- to do this test (this would be more important if procedure
1065 -- Force_Static_Allocation_Of_Referenced_Objects recursively
1066 -- traversed the declaration of an entity after marking it as
1067 -- statically allocated).
1069 and then not Is_Statically_Allocated
(Entity
(N
))
1071 Set_Is_Statically_Allocated
(Entity
(N
));
1077 procedure Fixup_Tree
is new Traverse_Proc
(Fixup_Node
);
1079 -- Start of processing for Force_Static_Allocation_Of_Referenced_Objects
1082 Fixup_Tree
(Aggregate
);
1083 end Force_Static_Allocation_Of_Referenced_Objects
;
1089 function Null_String
return String_Id
is
1092 Store_String_Char
(Get_Char_Code
(ASCII
.NUL
));
1100 Flag_Id
: Entity_Id
;
1103 -- Start of processing for Expand_N_Exception_Declaration
1106 -- Nothing to do when generating C code
1108 if Modify_Tree_For_C
then
1112 -- Definition of the external name: nam : constant String := "A.B.NAME";
1115 Make_Defining_Identifier
(Loc
, New_External_Name
(Chars
(Id
), 'E'));
1117 -- Do not generate an external name if the exception declaration is
1118 -- subject to pragma Discard_Names. Use a null-terminated empty name
1119 -- to ensure that Ada.Exceptions.Exception_Name functions properly.
1121 if Global_Discard_Names
or else Discard_Names
(Ex_Id
) then
1122 Ex_Val
:= Null_String
;
1124 -- Otherwise generate the fully qualified name of the exception
1127 Ex_Val
:= Fully_Qualified_Name_String
(Id
);
1131 Make_Object_Declaration
(Loc
,
1132 Defining_Identifier
=> Ex_Id
,
1133 Constant_Present
=> True,
1134 Object_Definition
=> New_Occurrence_Of
(Standard_String
, Loc
),
1135 Expression
=> Make_String_Literal
(Loc
, Ex_Val
)));
1137 Set_Is_Statically_Allocated
(Ex_Id
);
1139 -- Create the aggregate list for type Standard.Exception_Type:
1140 -- Not_Handled_By_Others component: False
1143 Append_To
(L
, New_Occurrence_Of
(Standard_False
, Loc
));
1145 -- Lang component: 'A'
1148 Make_Character_Literal
(Loc
,
1150 Char_Literal_Value
=> UI_From_CC
(Get_Char_Code
('A'))));
1152 -- Name_Length component: Nam'Length
1155 Make_Attribute_Reference
(Loc
,
1156 Prefix
=> New_Occurrence_Of
(Ex_Id
, Loc
),
1157 Attribute_Name
=> Name_Length
));
1159 -- Full_Name component: Standard_Address?(Nam'Address)
1160 -- or 0 if CodePeer_Mode
1162 if CodePeer_Mode
then
1163 Append_To
(L
, Make_Integer_Literal
(Loc
, Uint_0
));
1165 Append_To
(L
, OK_Convert_To
(Standard_Address
,
1166 Make_Attribute_Reference
(Loc
,
1167 Prefix
=> New_Occurrence_Of
(Ex_Id
, Loc
),
1168 Attribute_Name
=> Name_Address
)));
1171 -- HTable_Ptr component: null
1173 Append_To
(L
, Make_Null
(Loc
));
1175 -- Foreign_Data component: null address
1177 Append_To
(L
, Make_Integer_Literal
(Loc
, Uint_0
));
1179 -- Raise_Hook component: null
1181 Append_To
(L
, Make_Null
(Loc
));
1183 Set_Expression
(N
, Make_Aggregate
(Loc
, Expressions
=> L
));
1184 Analyze_And_Resolve
(Expression
(N
), Etype
(Id
));
1186 Force_Static_Allocation_Of_Referenced_Objects
(Expression
(N
));
1188 -- Register_Exception (except'Unrestricted_Access);
1190 if not No_Exception_Handlers_Set
1191 and then not Restriction_Active
(No_Exception_Registration
)
1194 Make_Procedure_Call_Statement
(Loc
,
1196 New_Occurrence_Of
(RTE
(RE_Register_Exception
), Loc
),
1197 Parameter_Associations
=> New_List
(
1198 Unchecked_Convert_To
(RTE
(RE_Exception_Data_Ptr
),
1199 Make_Attribute_Reference
(Loc
,
1200 Prefix
=> New_Occurrence_Of
(Id
, Loc
),
1201 Attribute_Name
=> Name_Unrestricted_Access
)))));
1203 Set_Register_Exception_Call
(Id
, First
(L
));
1205 if not Is_Library_Level_Entity
(Id
) then
1207 Make_Defining_Identifier
(Loc
,
1208 Chars
=> New_External_Name
(Chars
(Id
), 'F'));
1209 Set_Is_Statically_Allocated
(Flag_Id
);
1212 Use_Test_And_Set_Flag
: constant Boolean :=
1213 not Global_No_Tasking
1214 and then RTE_Available
(RE_Test_And_Set_Flag
);
1216 Flag_Decl
: Node_Id
;
1217 Condition
: Node_Id
;
1219 if Use_Test_And_Set_Flag
then
1221 Make_Object_Declaration
(Loc
,
1222 Defining_Identifier
=> Flag_Id
,
1223 Aliased_Present
=> True,
1224 Object_Definition
=>
1225 New_Occurrence_Of
(RTE
(RE_Test_And_Set_Flag
), Loc
));
1228 Make_Object_Declaration
(Loc
,
1229 Defining_Identifier
=> Flag_Id
,
1230 Object_Definition
=>
1231 New_Occurrence_Of
(Standard_Boolean
, Loc
),
1233 New_Occurrence_Of
(Standard_True
, Loc
));
1236 Insert_Action
(N
, Flag_Decl
);
1238 if Use_Test_And_Set_Flag
then
1241 Make_Function_Call
(Loc
,
1242 Name
=> New_Occurrence_Of
1243 (RTE
(RE_Atomic_Test_And_Set
), Loc
),
1244 Parameter_Associations
=>
1245 New_List
(New_Occurrence_Of
(Flag_Id
, Loc
))));
1247 Condition
:= New_Occurrence_Of
(Flag_Id
, Loc
);
1250 Make_Assignment_Statement
(Loc
,
1251 Name
=> New_Occurrence_Of
(Flag_Id
, Loc
),
1252 Expression
=> New_Occurrence_Of
(Standard_False
, Loc
)));
1255 Insert_After_And_Analyze
(N
,
1256 Make_Implicit_If_Statement
(N
,
1257 Condition
=> Condition
,
1258 Then_Statements
=> L
));
1261 Insert_List_After_And_Analyze
(N
, L
);
1264 end Expand_N_Exception_Declaration
;
1266 ---------------------------------------------
1267 -- Expand_N_Handled_Sequence_Of_Statements --
1268 ---------------------------------------------
1270 procedure Expand_N_Handled_Sequence_Of_Statements
(N
: Node_Id
) is
1272 -- Expand exception handlers
1274 if Present
(Exception_Handlers
(N
))
1275 and then not Restriction_Active
(No_Exception_Handlers
)
1277 Expand_Exception_Handlers
(N
);
1280 -- If local exceptions are being expanded, the previous call will
1281 -- have rewritten the construct as a block and reanalyzed it. No
1282 -- further expansion is needed.
1284 if Analyzed
(N
) then
1288 -- Add cleanup actions if required. No cleanup actions are needed in
1289 -- thunks associated with interfaces, because they only displace the
1290 -- pointer to the object. For extended return statements, we need
1291 -- cleanup actions if the Handled_Statement_Sequence contains generated
1292 -- objects of controlled types, for example. We do not want to clean up
1293 -- the return object.
1295 if Nkind
(Parent
(N
)) not in N_Accept_Statement
1296 | N_Extended_Return_Statement
1298 and then not Delay_Cleanups
(Current_Scope
)
1299 and then not Is_Thunk
(Current_Scope
)
1301 Expand_Cleanup_Actions
(Parent
(N
));
1303 elsif Nkind
(Parent
(N
)) = N_Extended_Return_Statement
1304 and then Handled_Statement_Sequence
(Parent
(N
)) = N
1305 and then not Delay_Cleanups
(Current_Scope
)
1307 pragma Assert
(not Is_Thunk
(Current_Scope
));
1308 Expand_Cleanup_Actions
(Parent
(N
));
1310 end Expand_N_Handled_Sequence_Of_Statements
;
1312 -------------------------------------
1313 -- Expand_N_Raise_Constraint_Error --
1314 -------------------------------------
1316 procedure Expand_N_Raise_Constraint_Error
(N
: Node_Id
) is
1318 -- We adjust the condition to deal with the C/Fortran boolean case. This
1319 -- may well not be necessary, as all such conditions are generated by
1320 -- the expander and probably are all standard boolean, but who knows
1321 -- what strange optimization in future may require this adjustment.
1323 Adjust_Condition
(Condition
(N
));
1325 -- Now deal with possible local raise handling
1327 Possible_Local_Raise
(N
, Standard_Constraint_Error
);
1328 end Expand_N_Raise_Constraint_Error
;
1330 -------------------------------
1331 -- Expand_N_Raise_Expression --
1332 -------------------------------
1334 procedure Expand_N_Raise_Expression
(N
: Node_Id
) is
1335 Loc
: constant Source_Ptr
:= Sloc
(N
);
1336 Typ
: constant Entity_Id
:= Etype
(N
);
1340 Possible_Local_Raise
(N
, Entity
(Name
(N
)));
1342 -- Later we must teach the back end/gigi how to deal with this, but
1343 -- for now we will assume the type is Standard_Boolean and transform
1347 -- raise X [with string]
1349 -- raise Constraint_Error;
1351 -- The raise constraint error can never be executed. It is just a dummy
1352 -- node that can be labeled with an arbitrary type.
1354 RCE
:= Make_Raise_Constraint_Error
(Loc
, Reason
=> CE_Explicit_Raise
);
1355 Set_Etype
(RCE
, Typ
);
1358 Make_Expression_With_Actions
(Loc
,
1359 Actions
=> New_List
(
1360 Make_Raise_Statement
(Loc
,
1362 Expression
=> Expression
(N
))),
1363 Expression
=> RCE
));
1365 Analyze_And_Resolve
(N
, Typ
);
1366 end Expand_N_Raise_Expression
;
1368 ----------------------------------
1369 -- Expand_N_Raise_Program_Error --
1370 ----------------------------------
1372 procedure Expand_N_Raise_Program_Error
(N
: Node_Id
) is
1374 -- We adjust the condition to deal with the C/Fortran boolean case. This
1375 -- may well not be necessary, as all such conditions are generated by
1376 -- the expander and probably are all standard boolean, but who knows
1377 -- what strange optimization in future may require this adjustment.
1379 Adjust_Condition
(Condition
(N
));
1381 -- Now deal with possible local raise handling
1383 Possible_Local_Raise
(N
, Standard_Program_Error
);
1384 end Expand_N_Raise_Program_Error
;
1386 ------------------------------
1387 -- Expand_N_Raise_Statement --
1388 ------------------------------
1390 procedure Expand_N_Raise_Statement
(N
: Node_Id
) is
1391 Loc
: constant Source_Ptr
:= Sloc
(N
);
1399 -- Processing for locally handled exception (exclude reraise case)
1401 if Present
(Name
(N
)) and then Is_Entity_Name
(Name
(N
)) then
1403 or else Restriction_Active
(No_Exception_Propagation
)
1405 -- If we have a local handler, then note that this is potentially
1406 -- able to be transformed into a goto statement.
1408 H
:= Find_Local_Handler
(Entity
(Name
(N
)), N
);
1411 if No
(Local_Raise_Statements
(H
)) then
1412 Set_Local_Raise_Statements
(H
, New_Elmt_List
);
1415 -- Append the new entry if it is not there already. Sometimes
1416 -- we have situations where due to reexpansion, the same node
1417 -- is analyzed twice and would otherwise be added twice.
1419 Append_Unique_Elmt
(N
, Local_Raise_Statements
(H
));
1420 Set_Has_Local_Raise
(H
);
1422 -- If no local handler, then generate no propagation warning
1425 Warn_If_No_Propagation
(N
);
1431 -- If a string expression is present, then the raise statement is
1432 -- converted to a call:
1433 -- Raise_Exception (exception-name'Identity, string);
1434 -- and there is nothing else to do.
1436 if Present
(Expression
(N
)) then
1438 -- Adjust message to deal with Prefix_Exception_Messages. We only
1439 -- add the prefix to string literals, if the message is being
1440 -- constructed, we assume it already deals with uniqueness.
1442 if Prefix_Exception_Messages
1443 and then Nkind
(Expression
(N
)) = N_String_Literal
1446 Buf
: Bounded_String
;
1448 Add_Source_Info
(Buf
, Loc
, Name_Enclosing_Entity
);
1450 Append
(Buf
, Strval
(Expression
(N
)));
1451 Rewrite
(Expression
(N
), Make_String_Literal
(Loc
, +Buf
));
1452 Analyze_And_Resolve
(Expression
(N
), Standard_String
);
1456 -- Avoid passing exception-name'identity in runtimes in which this
1457 -- argument is not used. This avoids generating undefined references
1458 -- to these exceptions when compiling with no optimization
1460 if Configurable_Run_Time_On_Target
1461 and then (Restriction_Active
(No_Exception_Handlers
)
1463 Restriction_Active
(No_Exception_Propagation
))
1466 Make_Procedure_Call_Statement
(Loc
,
1467 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1468 Parameter_Associations
=> New_List
(
1469 New_Occurrence_Of
(RTE
(RE_Null_Id
), Loc
),
1473 Make_Procedure_Call_Statement
(Loc
,
1474 Name
=> New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1475 Parameter_Associations
=> New_List
(
1476 Make_Attribute_Reference
(Loc
,
1478 Attribute_Name
=> Name_Identity
),
1486 -- Remaining processing is for the case where no string expression is
1489 -- Don't expand a raise statement that does not come from source if we
1490 -- have already had configurable run-time violations, since most likely
1491 -- it will be junk cascaded nonsense.
1493 if Configurable_Run_Time_Violations
> 0
1494 and then not Comes_From_Source
(N
)
1499 -- Convert explicit raise of Program_Error, Constraint_Error, and
1500 -- Storage_Error into the corresponding raise (in High_Integrity_Mode
1501 -- all other raises will get normal expansion and be disallowed,
1502 -- but this is also faster in all modes). Propagate Comes_From_Source
1503 -- flag to the new node.
1505 if Present
(Name
(N
)) and then Is_Entity_Name
(Name
(N
)) then
1506 Src
:= Comes_From_Source
(N
);
1508 if Entity
(Name
(N
)) = Standard_Constraint_Error
then
1510 Make_Raise_Constraint_Error
(Loc
, Reason
=> CE_Explicit_Raise
));
1511 Set_Comes_From_Source
(N
, Src
);
1515 elsif Entity
(Name
(N
)) = Standard_Program_Error
then
1517 Make_Raise_Program_Error
(Loc
, Reason
=> PE_Explicit_Raise
));
1518 Set_Comes_From_Source
(N
, Src
);
1522 elsif Entity
(Name
(N
)) = Standard_Storage_Error
then
1524 Make_Raise_Storage_Error
(Loc
, Reason
=> SE_Explicit_Raise
));
1525 Set_Comes_From_Source
(N
, Src
);
1531 -- Case of name present, in this case we expand raise name to
1533 -- Raise_Exception (name'Identity, location_string);
1535 -- where location_string identifies the file/line of the raise
1537 if Present
(Name
(N
)) and then Is_Entity_Name
(Name
(N
)) then
1539 Id
: Entity_Id
:= Entity
(Name
(N
));
1540 Buf
: Bounded_String
;
1543 Build_Location_String
(Buf
, Loc
);
1545 -- If the exception is a renaming, use the exception that it
1546 -- renames (which might be a predefined exception, e.g.).
1548 if Present
(Renamed_Entity
(Id
)) then
1549 Id
:= Renamed_Entity
(Id
);
1552 -- Build a C-compatible string in case of no exception handlers,
1553 -- since this is what the last chance handler is expecting.
1555 if No_Exception_Handlers_Set
then
1557 -- Generate an empty message if configuration pragma
1558 -- Suppress_Exception_Locations is set for this unit.
1560 if Opt
.Exception_Locations_Suppressed
then
1564 Append
(Buf
, ASCII
.NUL
);
1567 if Opt
.Exception_Locations_Suppressed
then
1571 Str
:= String_From_Name_Buffer
(Buf
);
1573 -- Convert raise to call to the Raise_Exception routine
1576 Make_Procedure_Call_Statement
(Loc
,
1578 New_Occurrence_Of
(RTE
(RE_Raise_Exception
), Loc
),
1579 Parameter_Associations
=> New_List
(
1580 Make_Attribute_Reference
(Loc
,
1582 Attribute_Name
=> Name_Identity
),
1583 Make_String_Literal
(Loc
, Strval
=> Str
))));
1586 -- Case of no name present (reraise). We rewrite the raise to:
1588 -- Reraise_Occurrence_Always (EO);
1590 -- where EO is the current exception occurrence. If the current handler
1591 -- does not have a choice parameter specification, then we provide one.
1594 -- Bypass expansion to a run-time call when back-end exception
1595 -- handling is active, unless the target is CodePeer, where
1596 -- raising an exception is treated as an error.
1598 if not CodePeer_Mode
then
1602 -- Find innermost enclosing exception handler (there must be one,
1603 -- since the semantics has already verified that this raise statement
1604 -- is valid, and a raise with no arguments is only permitted in the
1605 -- context of an exception handler).
1607 Ehand
:= Parent
(N
);
1608 while Nkind
(Ehand
) /= N_Exception_Handler
loop
1609 Ehand
:= Parent
(Ehand
);
1612 -- Make exception choice parameter if none present. Note that we do
1613 -- not need to put the entity on the entity chain, since no one will
1614 -- be referencing this entity by normal visibility methods.
1616 if No
(Choice_Parameter
(Ehand
)) then
1617 E
:= Make_Temporary
(Loc
, 'E');
1618 Set_Choice_Parameter
(Ehand
, E
);
1619 Mutate_Ekind
(E
, E_Variable
);
1620 Set_Etype
(E
, RTE
(RE_Exception_Occurrence
));
1621 Set_Scope
(E
, Current_Scope
);
1624 -- Now rewrite the raise as a call to Reraise. A special case arises
1625 -- if this raise statement occurs in the context of a handler for
1626 -- all others (i.e. an at end handler). in this case we avoid
1627 -- the call to defer abort, cleanup routines are expected to be
1628 -- called in this case with aborts deferred.
1631 Ech
: constant Node_Id
:= First
(Exception_Choices
(Ehand
));
1635 if Nkind
(Ech
) = N_Others_Choice
1636 and then All_Others
(Ech
)
1638 Ent
:= RTE
(RE_Reraise_Occurrence_No_Defer
);
1640 Ent
:= RTE
(RE_Reraise_Occurrence_Always
);
1644 Make_Procedure_Call_Statement
(Loc
,
1645 Name
=> New_Occurrence_Of
(Ent
, Loc
),
1646 Parameter_Associations
=> New_List
(
1647 New_Occurrence_Of
(Choice_Parameter
(Ehand
), Loc
))));
1652 end Expand_N_Raise_Statement
;
1654 -----------------------------------
1655 -- Expand_N_Raise_When_Statement --
1656 -----------------------------------
1658 procedure Expand_N_Raise_When_Statement
(N
: Node_Id
) is
1659 Loc
: constant Source_Ptr
:= Sloc
(N
);
1662 Make_If_Statement
(Loc
,
1663 Condition
=> Condition
(N
),
1664 Then_Statements
=> New_List
(
1665 Make_Raise_Statement
(Loc
,
1667 Expression
=> Expression
(N
)))));
1670 end Expand_N_Raise_When_Statement
;
1672 ----------------------------------
1673 -- Expand_N_Raise_Storage_Error --
1674 ----------------------------------
1676 procedure Expand_N_Raise_Storage_Error
(N
: Node_Id
) is
1678 -- We adjust the condition to deal with the C/Fortran boolean case. This
1679 -- may well not be necessary, as all such conditions are generated by
1680 -- the expander and probably are all standard boolean, but who knows
1681 -- what strange optimization in future may require this adjustment.
1683 Adjust_Condition
(Condition
(N
));
1685 -- Now deal with possible local raise handling
1687 Possible_Local_Raise
(N
, Standard_Storage_Error
);
1688 end Expand_N_Raise_Storage_Error
;
1690 --------------------------
1691 -- Possible_Local_Raise --
1692 --------------------------
1694 procedure Possible_Local_Raise
(N
: Node_Id
; E
: Entity_Id
) is
1696 -- Nothing to do if local raise optimization not active
1698 if not Debug_Flag_Dot_G
1699 and then not Restriction_Active
(No_Exception_Propagation
)
1704 -- Nothing to do if original node was an explicit raise, because in
1705 -- that case, we already generated the required warning for the raise.
1707 if Nkind
(Original_Node
(N
)) = N_Raise_Statement
then
1711 -- Otherwise see if we have a local handler for the exception
1714 H
: constant Node_Id
:= Find_Local_Handler
(E
, N
);
1717 -- If so, mark that it has a local raise
1720 Set_Has_Local_Raise
(H
, True);
1722 -- Otherwise, if the No_Exception_Propagation restriction is active
1723 -- and the warning is enabled, generate the appropriate warnings.
1725 -- ??? Do not do it for the Call_Marker nodes inserted by the ABE
1726 -- mechanism because this generates too many false positives, or
1727 -- for generic instantiations for the same reason.
1729 elsif Warn_On_Non_Local_Exception
1730 and then Restriction_Active
(No_Exception_Propagation
)
1731 and then Nkind
(N
) /= N_Call_Marker
1732 and then Nkind
(N
) not in N_Generic_Instantiation
1734 Warn_No_Exception_Propagation_Active
(N
);
1736 if Configurable_Run_Time_Mode
then
1738 ("\?.x?& may call Last_Chance_Handler", N
, E
);
1741 ("\?.x?& may result in unhandled exception", N
, E
);
1745 end Possible_Local_Raise
;
1747 ------------------------
1748 -- Find_Local_Handler --
1749 ------------------------
1751 function Find_Local_Handler
1753 Nod
: Node_Id
) return Node_Id
1760 SSE
: Scope_Stack_Entry
renames Scope_Stack
.Table
(Scope_Stack
.Last
);
1761 -- This is used to test for wrapped actions below
1764 EHandle
: Entity_Id
;
1765 -- The entity Id's for the exception we are raising and handling, using
1766 -- the renamed exception if a Renamed_Entity is present.
1769 -- Never any local handler if all handlers removed
1771 if Debug_Flag_Dot_X
then
1775 -- Get the exception we are raising, allowing for renaming
1777 ERaise
:= Get_Renamed_Entity
(Ename
);
1779 -- We need to check if the node we are looking at is contained in
1782 -- Loop to search up the tree
1788 -- If we get to the top of the tree, or to a subprogram, task, entry,
1789 -- protected body, or accept statement without having found a
1790 -- matching handler, then there is no local handler.
1793 or else Nkind
(P
) = N_Subprogram_Body
1794 or else Nkind
(P
) = N_Task_Body
1795 or else Nkind
(P
) = N_Protected_Body
1796 or else Nkind
(P
) = N_Entry_Body
1797 or else Nkind
(P
) = N_Accept_Statement
1801 -- Test for handled sequence of statements with at least one
1802 -- exception handler which might be the one we are looking for.
1804 -- We need to check if the node N is covered by the statement part of
1805 -- P rather than one of its exception handlers (an exception handler
1806 -- obviously does not cover its own statements).
1808 -- This test is more delicate than might be thought. It is not just
1809 -- a matter of checking the Statements (P), because the node might be
1810 -- waiting to be wrapped in a transient scope, in which case it will
1811 -- end up in the block statements, even though it is not there now.
1813 elsif Nkind
(P
) = N_Handled_Sequence_Of_Statements
1814 and then Is_List_Member
(N
)
1815 and then List_Containing
(N
) in Statements
(P
)
1816 | SSE
.Actions_To_Be_Wrapped
(Before
)
1817 | SSE
.Actions_To_Be_Wrapped
(After
)
1818 | SSE
.Actions_To_Be_Wrapped
(Cleanup
)
1820 -- Loop through exception handlers and guard against pragmas
1821 -- appearing among them.
1823 H
:= First_Non_Pragma
(Exception_Handlers
(P
));
1824 while Present
(H
) loop
1826 -- Guard against other constructs appearing in the list of
1827 -- exception handlers.
1829 -- Loop through choices in one handler
1831 C
:= First
(Exception_Choices
(H
));
1832 while Present
(C
) loop
1834 -- Deal with others case
1836 if Nkind
(C
) = N_Others_Choice
then
1838 -- Matching others handler, but we need to ensure there
1839 -- is no choice parameter. If there is, then we don't
1840 -- have a local handler after all (since we do not allow
1841 -- choice parameters for local handlers).
1843 if No
(Choice_Parameter
(H
)) then
1849 -- If not others must be entity name
1852 pragma Assert
(Is_Entity_Name
(C
));
1853 pragma Assert
(Present
(Entity
(C
)));
1855 -- Get exception being handled, dealing with renaming
1857 EHandle
:= Get_Renamed_Entity
(Entity
(C
));
1859 -- If match, then check choice parameter
1861 if ERaise
= EHandle
then
1862 if No
(Choice_Parameter
(H
)) then
1873 Next_Non_Pragma
(H
);
1879 end Find_Local_Handler
;
1881 ---------------------------------
1882 -- Get_Local_Raise_Call_Entity --
1883 ---------------------------------
1885 -- Note: this is primarily provided for use by the back end in generating
1886 -- calls to Local_Raise. But it would be too late in the back end to call
1887 -- RTE if this actually caused a load/analyze of the unit. So what we do
1888 -- is to ensure there is a dummy call to this function during front end
1889 -- processing so that the unit gets loaded then, and not later.
1891 Local_Raise_Call_Entity
: Entity_Id
;
1892 Local_Raise_Call_Entity_Set
: Boolean := False;
1894 function Get_Local_Raise_Call_Entity
return Entity_Id
is
1896 if not Local_Raise_Call_Entity_Set
then
1897 Local_Raise_Call_Entity_Set
:= True;
1899 if RTE_Available
(RE_Local_Raise
) then
1900 Local_Raise_Call_Entity
:= RTE
(RE_Local_Raise
);
1902 Local_Raise_Call_Entity
:= Empty
;
1906 return Local_Raise_Call_Entity
;
1907 end Get_Local_Raise_Call_Entity
;
1909 -----------------------------
1910 -- Get_RT_Exception_Entity --
1911 -----------------------------
1913 function Get_RT_Exception_Entity
(R
: RT_Exception_Code
) return Entity_Id
is
1916 when CE_Reason
=> return Standard_Constraint_Error
;
1917 when PE_Reason
=> return Standard_Program_Error
;
1918 when SE_Reason
=> return Standard_Storage_Error
;
1920 end Get_RT_Exception_Entity
;
1922 ---------------------------
1923 -- Get_RT_Exception_Name --
1924 ---------------------------
1926 procedure Get_RT_Exception_Name
(Code
: RT_Exception_Code
) is
1929 when CE_Access_Check_Failed
=>
1930 Add_Str_To_Name_Buffer
("CE_Access_Check");
1931 when CE_Access_Parameter_Is_Null
=>
1932 Add_Str_To_Name_Buffer
("CE_Null_Access_Parameter");
1933 when CE_Discriminant_Check_Failed
=>
1934 Add_Str_To_Name_Buffer
("CE_Discriminant_Check");
1935 when CE_Divide_By_Zero
=>
1936 Add_Str_To_Name_Buffer
("CE_Divide_By_Zero");
1937 when CE_Explicit_Raise
=>
1938 Add_Str_To_Name_Buffer
("CE_Explicit_Raise");
1939 when CE_Index_Check_Failed
=>
1940 Add_Str_To_Name_Buffer
("CE_Index_Check");
1941 when CE_Invalid_Data
=>
1942 Add_Str_To_Name_Buffer
("CE_Invalid_Data");
1943 when CE_Length_Check_Failed
=>
1944 Add_Str_To_Name_Buffer
("CE_Length_Check");
1945 when CE_Null_Exception_Id
=>
1946 Add_Str_To_Name_Buffer
("CE_Null_Exception_Id");
1947 when CE_Null_Not_Allowed
=>
1948 Add_Str_To_Name_Buffer
("CE_Null_Not_Allowed");
1949 when CE_Overflow_Check_Failed
=>
1950 Add_Str_To_Name_Buffer
("CE_Overflow_Check");
1951 when CE_Partition_Check_Failed
=>
1952 Add_Str_To_Name_Buffer
("CE_Partition_Check");
1953 when CE_Range_Check_Failed
=>
1954 Add_Str_To_Name_Buffer
("CE_Range_Check");
1955 when CE_Tag_Check_Failed
=>
1956 Add_Str_To_Name_Buffer
("CE_Tag_Check");
1958 when PE_Access_Before_Elaboration
=>
1959 Add_Str_To_Name_Buffer
("PE_Access_Before_Elaboration");
1960 when PE_Accessibility_Check_Failed
=>
1961 Add_Str_To_Name_Buffer
("PE_Accessibility_Check");
1962 when PE_Address_Of_Intrinsic
=>
1963 Add_Str_To_Name_Buffer
("PE_Address_Of_Intrinsic");
1964 when PE_Aliased_Parameters
=>
1965 Add_Str_To_Name_Buffer
("PE_Aliased_Parameters");
1966 when PE_All_Guards_Closed
=>
1967 Add_Str_To_Name_Buffer
("PE_All_Guards_Closed");
1968 when PE_Bad_Predicated_Generic_Type
=>
1969 Add_Str_To_Name_Buffer
("PE_Bad_Predicated_Generic_Type");
1970 when PE_Build_In_Place_Mismatch
=>
1971 Add_Str_To_Name_Buffer
("PE_Build_In_Place_Mismatch");
1972 when PE_Current_Task_In_Entry_Body
=>
1973 Add_Str_To_Name_Buffer
("PE_Current_Task_In_Entry_Body");
1974 when PE_Duplicated_Entry_Address
=>
1975 Add_Str_To_Name_Buffer
("PE_Duplicated_Entry_Address");
1976 when PE_Explicit_Raise
=>
1977 Add_Str_To_Name_Buffer
("PE_Explicit_Raise");
1978 when PE_Finalize_Raised_Exception
=>
1979 Add_Str_To_Name_Buffer
("PE_Finalize_Raised_Exception");
1980 when PE_Implicit_Return
=>
1981 Add_Str_To_Name_Buffer
("PE_Implicit_Return");
1982 when PE_Misaligned_Address_Value
=>
1983 Add_Str_To_Name_Buffer
("PE_Misaligned_Address_Value");
1984 when PE_Missing_Return
=>
1985 Add_Str_To_Name_Buffer
("PE_Missing_Return");
1986 when PE_Non_Transportable_Actual
=>
1987 Add_Str_To_Name_Buffer
("PE_Non_Transportable_Actual");
1988 when PE_Overlaid_Controlled_Object
=>
1989 Add_Str_To_Name_Buffer
("PE_Overlaid_Controlled_Object");
1990 when PE_Potentially_Blocking_Operation
=>
1991 Add_Str_To_Name_Buffer
("PE_Potentially_Blocking_Operation");
1992 when PE_Stream_Operation_Not_Allowed
=>
1993 Add_Str_To_Name_Buffer
("PE_Stream_Operation_Not_Allowed");
1994 when PE_Stubbed_Subprogram_Called
=>
1995 Add_Str_To_Name_Buffer
("PE_Stubbed_Subprogram_Called");
1996 when PE_Unchecked_Union_Restriction
=>
1997 Add_Str_To_Name_Buffer
("PE_Unchecked_Union_Restriction");
1999 when SE_Empty_Storage_Pool
=>
2000 Add_Str_To_Name_Buffer
("SE_Empty_Storage_Pool");
2001 when SE_Explicit_Raise
=>
2002 Add_Str_To_Name_Buffer
("SE_Explicit_Raise");
2003 when SE_Infinite_Recursion
=>
2004 Add_Str_To_Name_Buffer
("SE_Infinite_Recursion");
2005 when SE_Object_Too_Large
=>
2006 Add_Str_To_Name_Buffer
("SE_Object_Too_Large");
2008 end Get_RT_Exception_Name
;
2010 ----------------------------
2011 -- Warn_If_No_Local_Raise --
2012 ----------------------------
2014 procedure Warn_If_No_Local_Raise
(N
: Node_Id
) is
2016 if Restriction_Active
(No_Exception_Propagation
)
2017 and then Warn_On_Non_Local_Exception
2019 Warn_No_Exception_Propagation_Active
(N
);
2022 ("\?.x?this handler can never be entered, and has been removed", N
);
2024 end Warn_If_No_Local_Raise
;
2026 ----------------------------
2027 -- Warn_If_No_Propagation --
2028 ----------------------------
2030 procedure Warn_If_No_Propagation
(N
: Node_Id
) is
2032 if Restriction_Check_Required
(No_Exception_Propagation
)
2033 and then Warn_On_Non_Local_Exception
2035 Warn_No_Exception_Propagation_Active
(N
);
2037 if Configurable_Run_Time_Mode
then
2039 ("\?.x?Last_Chance_Handler will be called on exception", N
);
2042 ("\?.x?execution may raise unhandled exception", N
);
2045 end Warn_If_No_Propagation
;
2047 ------------------------------------------
2048 -- Warn_No_Exception_Propagation_Active --
2049 ------------------------------------------
2051 procedure Warn_No_Exception_Propagation_Active
(N
: Node_Id
) is
2054 ("?.x?pragma Restrictions (No_Exception_Propagation) in effect", N
);
2055 end Warn_No_Exception_Propagation_Active
;