1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
29 #include "pointer-set.h"
30 #include "tree-flow.h"
31 #include "tree-dump.h"
32 #include "tree-inline.h"
33 #include "tree-iterator.h"
34 #include "tree-pass.h"
36 #include "langhooks.h"
42 /* In some instances a tree and a gimple need to be stored in a same table,
43 i.e. in hash tables. This is a structure to do this. */
44 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
46 /* Nonzero if we are using EH to handle cleanups. */
47 static int using_eh_for_cleanups_p
= 0;
50 using_eh_for_cleanups (void)
52 using_eh_for_cleanups_p
= 1;
55 /* Misc functions used in this file. */
57 /* Compare and hash for any structure which begins with a canonical
58 pointer. Assumes all pointers are interchangeable, which is sort
59 of already assumed by gcc elsewhere IIRC. */
62 struct_ptr_eq (const void *a
, const void *b
)
64 const void * const * x
= (const void * const *) a
;
65 const void * const * y
= (const void * const *) b
;
70 struct_ptr_hash (const void *a
)
72 const void * const * x
= (const void * const *) a
;
73 return (size_t)*x
>> 4;
77 /* Remember and lookup EH landing pad data for arbitrary statements.
78 Really this means any statement that could_throw_p. We could
79 stuff this information into the stmt_ann data structure, but:
81 (1) We absolutely rely on this information being kept until
82 we get to rtl. Once we're done with lowering here, if we lose
83 the information there's no way to recover it!
85 (2) There are many more statements that *cannot* throw as
86 compared to those that can. We should be saving some amount
87 of space by only allocating memory for those that can throw. */
89 /* Add statement T in function IFUN to landing pad NUM. */
92 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
94 struct throw_stmt_node
*n
;
97 gcc_assert (num
!= 0);
99 n
= GGC_NEW (struct throw_stmt_node
);
103 if (!get_eh_throw_stmt_table (ifun
))
104 set_eh_throw_stmt_table (ifun
, htab_create_ggc (31, struct_ptr_hash
,
108 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), n
, INSERT
);
113 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
116 add_stmt_to_eh_lp (gimple t
, int num
)
118 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
121 /* Add statement T to the single EH landing pad in REGION. */
124 record_stmt_eh_region (eh_region region
, gimple t
)
128 if (region
->type
== ERT_MUST_NOT_THROW
)
129 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
132 eh_landing_pad lp
= region
->landing_pads
;
134 lp
= gen_eh_landing_pad (region
);
136 gcc_assert (lp
->next_lp
== NULL
);
137 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
142 /* Remove statement T in function IFUN from its EH landing pad. */
145 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
147 struct throw_stmt_node dummy
;
150 if (!get_eh_throw_stmt_table (ifun
))
154 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), &dummy
,
158 htab_clear_slot (get_eh_throw_stmt_table (ifun
), slot
);
166 /* Remove statement T in the current function (cfun) from its
170 remove_stmt_from_eh_lp (gimple t
)
172 return remove_stmt_from_eh_lp_fn (cfun
, t
);
175 /* Determine if statement T is inside an EH region in function IFUN.
176 Positive numbers indicate a landing pad index; negative numbers
177 indicate a MUST_NOT_THROW region index; zero indicates that the
178 statement is not recorded in the region table. */
181 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
183 struct throw_stmt_node
*p
, n
;
185 if (ifun
->eh
->throw_stmt_table
== NULL
)
189 p
= (struct throw_stmt_node
*) htab_find (ifun
->eh
->throw_stmt_table
, &n
);
190 return p
? p
->lp_nr
: 0;
193 /* Likewise, but always use the current function. */
196 lookup_stmt_eh_lp (gimple t
)
198 /* We can get called from initialized data when -fnon-call-exceptions
199 is on; prevent crash. */
202 return lookup_stmt_eh_lp_fn (cfun
, t
);
205 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
206 nodes and LABEL_DECL nodes. We will use this during the second phase to
207 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
209 struct finally_tree_node
211 /* When storing a GIMPLE_TRY, we have to record a gimple. However
212 when deciding whether a GOTO to a certain LABEL_DECL (which is a
213 tree) leaves the TRY block, its necessary to record a tree in
214 this field. Thus a treemple is used. */
219 /* Note that this table is *not* marked GTY. It is short-lived. */
220 static htab_t finally_tree
;
223 record_in_finally_tree (treemple child
, gimple parent
)
225 struct finally_tree_node
*n
;
228 n
= XNEW (struct finally_tree_node
);
232 slot
= htab_find_slot (finally_tree
, n
, INSERT
);
238 collect_finally_tree (gimple stmt
, gimple region
);
240 /* Go through the gimple sequence. Works with collect_finally_tree to
241 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
244 collect_finally_tree_1 (gimple_seq seq
, gimple region
)
246 gimple_stmt_iterator gsi
;
248 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
249 collect_finally_tree (gsi_stmt (gsi
), region
);
253 collect_finally_tree (gimple stmt
, gimple region
)
257 switch (gimple_code (stmt
))
260 temp
.t
= gimple_label_label (stmt
);
261 record_in_finally_tree (temp
, region
);
265 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
268 record_in_finally_tree (temp
, region
);
269 collect_finally_tree_1 (gimple_try_eval (stmt
), stmt
);
270 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
272 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
274 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
275 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
280 collect_finally_tree_1 (gimple_catch_handler (stmt
), region
);
283 case GIMPLE_EH_FILTER
:
284 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
288 /* A type, a decl, or some kind of statement that we're not
289 interested in. Don't walk them. */
295 /* Use the finally tree to determine if a jump from START to TARGET
296 would leave the try_finally node that START lives in. */
299 outside_finally_tree (treemple start
, gimple target
)
301 struct finally_tree_node n
, *p
;
306 p
= (struct finally_tree_node
*) htab_find (finally_tree
, &n
);
311 while (start
.g
!= target
);
316 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
317 nodes into a set of gotos, magic labels, and eh regions.
318 The eh region creation is straight-forward, but frobbing all the gotos
319 and such into shape isn't. */
321 /* The sequence into which we record all EH stuff. This will be
322 placed at the end of the function when we're all done. */
323 static gimple_seq eh_seq
;
325 /* Record whether an EH region contains something that can throw,
326 indexed by EH region number. */
327 static bitmap eh_region_may_contain_throw_map
;
329 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
330 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
331 The idea is to record a gimple statement for everything except for
332 the conditionals, which get their labels recorded. Since labels are
333 of type 'tree', we need this node to store both gimple and tree
334 objects. REPL_STMT is the sequence used to replace the goto/return
335 statement. CONT_STMT is used to store the statement that allows
336 the return/goto to jump to the original destination. */
338 struct goto_queue_node
341 gimple_seq repl_stmt
;
344 /* This is used when index >= 0 to indicate that stmt is a label (as
345 opposed to a goto stmt). */
349 /* State of the world while lowering. */
353 /* What's "current" while constructing the eh region tree. These
354 correspond to variables of the same name in cfun->eh, which we
355 don't have easy access to. */
356 eh_region cur_region
;
358 /* What's "current" for the purposes of __builtin_eh_pointer. For
359 a CATCH, this is the associated TRY. For an EH_FILTER, this is
360 the associated ALLOWED_EXCEPTIONS, etc. */
361 eh_region ehp_region
;
363 /* Processing of TRY_FINALLY requires a bit more state. This is
364 split out into a separate structure so that we don't have to
365 copy so much when processing other nodes. */
366 struct leh_tf_state
*tf
;
371 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
372 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
373 this so that outside_finally_tree can reliably reference the tree used
374 in the collect_finally_tree data structures. */
375 gimple try_finally_expr
;
378 /* While lowering a top_p usually it is expanded into multiple statements,
379 thus we need the following field to store them. */
380 gimple_seq top_p_seq
;
382 /* The state outside this try_finally node. */
383 struct leh_state
*outer
;
385 /* The exception region created for it. */
388 /* The goto queue. */
389 struct goto_queue_node
*goto_queue
;
390 size_t goto_queue_size
;
391 size_t goto_queue_active
;
393 /* Pointer map to help in searching goto_queue when it is large. */
394 struct pointer_map_t
*goto_queue_map
;
396 /* The set of unique labels seen as entries in the goto queue. */
397 VEC(tree
,heap
) *dest_array
;
399 /* A label to be added at the end of the completed transformed
400 sequence. It will be set if may_fallthru was true *at one time*,
401 though subsequent transformations may have cleared that flag. */
404 /* True if it is possible to fall out the bottom of the try block.
405 Cleared if the fallthru is converted to a goto. */
408 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
411 /* True if the finally block can receive an exception edge.
412 Cleared if the exception case is handled by code duplication. */
416 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gimple
);
418 /* Search for STMT in the goto queue. Return the replacement,
419 or null if the statement isn't in the queue. */
421 #define LARGE_GOTO_QUEUE 20
423 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
);
426 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
431 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
433 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
434 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
435 return tf
->goto_queue
[i
].repl_stmt
;
439 /* If we have a large number of entries in the goto_queue, create a
440 pointer map and use that for searching. */
442 if (!tf
->goto_queue_map
)
444 tf
->goto_queue_map
= pointer_map_create ();
445 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
447 slot
= pointer_map_insert (tf
->goto_queue_map
,
448 tf
->goto_queue
[i
].stmt
.g
);
449 gcc_assert (*slot
== NULL
);
450 *slot
= &tf
->goto_queue
[i
];
454 slot
= pointer_map_contains (tf
->goto_queue_map
, stmt
.g
);
456 return (((struct goto_queue_node
*) *slot
)->repl_stmt
);
461 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
462 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
463 then we can just splat it in, otherwise we add the new stmts immediately
464 after the GIMPLE_COND and redirect. */
467 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
468 gimple_stmt_iterator
*gsi
)
473 location_t loc
= gimple_location (gsi_stmt (*gsi
));
476 new_seq
= find_goto_replacement (tf
, temp
);
480 if (gimple_seq_singleton_p (new_seq
)
481 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
483 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
487 label
= create_artificial_label (loc
);
488 /* Set the new label for the GIMPLE_COND */
491 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
492 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
495 /* The real work of replace_goto_queue. Returns with TSI updated to
496 point to the next statement. */
498 static void replace_goto_queue_stmt_list (gimple_seq
, struct leh_tf_state
*);
501 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
502 gimple_stmt_iterator
*gsi
)
508 switch (gimple_code (stmt
))
513 seq
= find_goto_replacement (tf
, temp
);
516 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
517 gsi_remove (gsi
, false);
523 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
524 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
528 replace_goto_queue_stmt_list (gimple_try_eval (stmt
), tf
);
529 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt
), tf
);
532 replace_goto_queue_stmt_list (gimple_catch_handler (stmt
), tf
);
534 case GIMPLE_EH_FILTER
:
535 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt
), tf
);
539 /* These won't have gotos in them. */
546 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
549 replace_goto_queue_stmt_list (gimple_seq seq
, struct leh_tf_state
*tf
)
551 gimple_stmt_iterator gsi
= gsi_start (seq
);
553 while (!gsi_end_p (gsi
))
554 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
557 /* Replace all goto queue members. */
560 replace_goto_queue (struct leh_tf_state
*tf
)
562 if (tf
->goto_queue_active
== 0)
564 replace_goto_queue_stmt_list (tf
->top_p_seq
, tf
);
565 replace_goto_queue_stmt_list (eh_seq
, tf
);
568 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
569 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
573 record_in_goto_queue (struct leh_tf_state
*tf
,
579 struct goto_queue_node
*q
;
581 gcc_assert (!tf
->goto_queue_map
);
583 active
= tf
->goto_queue_active
;
584 size
= tf
->goto_queue_size
;
587 size
= (size
? size
* 2 : 32);
588 tf
->goto_queue_size
= size
;
590 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
593 q
= &tf
->goto_queue
[active
];
594 tf
->goto_queue_active
= active
+ 1;
596 memset (q
, 0, sizeof (*q
));
599 q
->is_label
= is_label
;
602 /* Record the LABEL label in the goto queue contained in TF.
606 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
)
609 treemple temp
, new_stmt
;
614 /* Computed and non-local gotos do not get processed. Given
615 their nature we can neither tell whether we've escaped the
616 finally block nor redirect them if we knew. */
617 if (TREE_CODE (label
) != LABEL_DECL
)
620 /* No need to record gotos that don't leave the try block. */
622 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
625 if (! tf
->dest_array
)
627 tf
->dest_array
= VEC_alloc (tree
, heap
, 10);
628 VEC_quick_push (tree
, tf
->dest_array
, label
);
633 int n
= VEC_length (tree
, tf
->dest_array
);
634 for (index
= 0; index
< n
; ++index
)
635 if (VEC_index (tree
, tf
->dest_array
, index
) == label
)
638 VEC_safe_push (tree
, heap
, tf
->dest_array
, label
);
641 /* In the case of a GOTO we want to record the destination label,
642 since with a GIMPLE_COND we have an easy access to the then/else
645 record_in_goto_queue (tf
, new_stmt
, index
, true);
648 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
649 node, and if so record that fact in the goto queue associated with that
653 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
655 struct leh_tf_state
*tf
= state
->tf
;
661 switch (gimple_code (stmt
))
664 new_stmt
.tp
= gimple_op_ptr (stmt
, 2);
665 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_true_label (stmt
));
666 new_stmt
.tp
= gimple_op_ptr (stmt
, 3);
667 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_false_label (stmt
));
671 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
));
675 tf
->may_return
= true;
677 record_in_goto_queue (tf
, new_stmt
, -1, false);
686 #ifdef ENABLE_CHECKING
687 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
688 was in fact structured, and we've not yet done jump threading, then none
689 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
692 verify_norecord_switch_expr (struct leh_state
*state
, gimple switch_expr
)
694 struct leh_tf_state
*tf
= state
->tf
;
700 n
= gimple_switch_num_labels (switch_expr
);
702 for (i
= 0; i
< n
; ++i
)
705 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
707 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
711 #define verify_norecord_switch_expr(state, switch_expr)
714 /* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P
715 whatever is needed to finish the return. If MOD is non-null, insert it
716 before the new branch. RETURN_VALUE_P is a cache containing a temporary
717 variable to be used in manipulating the value returned from the function. */
720 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
721 tree
*return_value_p
)
726 /* In the case of a return, the queue node must be a gimple statement. */
727 gcc_assert (!q
->is_label
);
729 ret_expr
= gimple_return_retval (q
->stmt
.g
);
733 if (!*return_value_p
)
734 *return_value_p
= ret_expr
;
736 gcc_assert (*return_value_p
== ret_expr
);
737 q
->cont_stmt
= q
->stmt
.g
;
738 /* The nasty part about redirecting the return value is that the
739 return value itself is to be computed before the FINALLY block
753 should return 0, not 1. Arrange for this to happen by copying
754 computed the return value into a local temporary. This also
755 allows us to redirect multiple return statements through the
756 same destination block; whether this is a net win or not really
757 depends, I guess, but it does make generation of the switch in
758 lower_try_finally_switch easier. */
760 if (TREE_CODE (ret_expr
) == RESULT_DECL
)
762 if (!*return_value_p
)
763 *return_value_p
= ret_expr
;
765 gcc_assert (*return_value_p
== ret_expr
);
766 q
->cont_stmt
= q
->stmt
.g
;
772 /* If we don't return a value, all return statements are the same. */
773 q
->cont_stmt
= q
->stmt
.g
;
776 q
->repl_stmt
= gimple_seq_alloc ();
779 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
781 x
= gimple_build_goto (finlab
);
782 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
785 /* Similar, but easier, for GIMPLE_GOTO. */
788 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
789 struct leh_tf_state
*tf
)
793 gcc_assert (q
->is_label
);
795 q
->repl_stmt
= gimple_seq_alloc ();
797 q
->cont_stmt
= gimple_build_goto (VEC_index (tree
, tf
->dest_array
, q
->index
));
800 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
802 x
= gimple_build_goto (finlab
);
803 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
806 /* Emit a standard landing pad sequence into SEQ for REGION. */
809 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
811 eh_landing_pad lp
= region
->landing_pads
;
815 lp
= gen_eh_landing_pad (region
);
817 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
818 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
820 x
= gimple_build_label (lp
->post_landing_pad
);
821 gimple_seq_add_stmt (seq
, x
);
824 /* Emit a RESX statement into SEQ for REGION. */
827 emit_resx (gimple_seq
*seq
, eh_region region
)
829 gimple x
= gimple_build_resx (region
->index
);
830 gimple_seq_add_stmt (seq
, x
);
832 record_stmt_eh_region (region
->outer
, x
);
835 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
838 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
840 gimple x
= gimple_build_eh_dispatch (region
->index
);
841 gimple_seq_add_stmt (seq
, x
);
844 /* Note that the current EH region may contain a throw, or a
845 call to a function which itself may contain a throw. */
848 note_eh_region_may_contain_throw (eh_region region
)
850 while (!bitmap_bit_p (eh_region_may_contain_throw_map
, region
->index
))
852 bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
);
853 region
= region
->outer
;
859 /* Check if REGION has been marked as containing a throw. If REGION is
860 NULL, this predicate is false. */
863 eh_region_may_contain_throw (eh_region r
)
865 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
868 /* We want to transform
869 try { body; } catch { stuff; }
879 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
880 should be placed before the second operand, or NULL. OVER is
881 an existing label that should be put at the exit, or NULL. */
884 frob_into_branch_around (gimple tp
, eh_region region
, tree over
)
887 gimple_seq cleanup
, result
;
888 location_t loc
= gimple_location (tp
);
890 cleanup
= gimple_try_cleanup (tp
);
891 result
= gimple_try_eval (tp
);
894 emit_post_landing_pad (&eh_seq
, region
);
896 if (gimple_seq_may_fallthru (cleanup
))
899 over
= create_artificial_label (loc
);
900 x
= gimple_build_goto (over
);
901 gimple_seq_add_stmt (&cleanup
, x
);
903 gimple_seq_add_seq (&eh_seq
, cleanup
);
907 x
= gimple_build_label (over
);
908 gimple_seq_add_stmt (&result
, x
);
913 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
914 Make sure to record all new labels found. */
917 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
)
919 gimple region
= NULL
;
922 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
925 region
= outer_state
->tf
->try_finally_expr
;
926 collect_finally_tree_1 (new_seq
, region
);
931 /* A subroutine of lower_try_finally. Create a fallthru label for
932 the given try_finally state. The only tricky bit here is that
933 we have to make sure to record the label in our outer context. */
936 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
938 tree label
= tf
->fallthru_label
;
943 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
944 tf
->fallthru_label
= label
;
948 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
954 /* A subroutine of lower_try_finally. If lang_protect_cleanup_actions
955 returns non-null, then the language requires that the exception path out
956 of a try_finally be treated specially. To wit: the code within the
957 finally block may not itself throw an exception. We have two choices here.
958 First we can duplicate the finally block and wrap it in a must_not_throw
959 region. Second, we can generate code like
964 if (fintmp == eh_edge)
965 protect_cleanup_actions;
968 where "fintmp" is the temporary used in the switch statement generation
969 alternative considered below. For the nonce, we always choose the first
972 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
975 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
976 struct leh_state
*this_state
,
977 struct leh_tf_state
*tf
)
979 tree protect_cleanup_actions
;
980 gimple_stmt_iterator gsi
;
981 bool finally_may_fallthru
;
985 /* First check for nothing to do. */
986 if (lang_protect_cleanup_actions
== NULL
)
988 protect_cleanup_actions
= lang_protect_cleanup_actions ();
989 if (protect_cleanup_actions
== NULL
)
992 finally
= gimple_try_cleanup (tf
->top_p
);
993 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
995 /* Duplicate the FINALLY block. Only need to do this for try-finally,
996 and not for cleanups. */
998 finally
= lower_try_finally_dup_block (finally
, outer_state
);
1000 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1001 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1002 to be in an enclosing scope, but needs to be implemented at this level
1003 to avoid a nesting violation (see wrap_temporary_cleanups in
1004 cp/decl.c). Since it's logically at an outer level, we should call
1005 terminate before we get to it, so strip it away before adding the
1006 MUST_NOT_THROW filter. */
1007 gsi
= gsi_start (finally
);
1009 if (gimple_code (x
) == GIMPLE_TRY
1010 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1011 && gimple_try_catch_is_cleanup (x
))
1013 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1014 gsi_remove (&gsi
, false);
1017 /* Wrap the block with protect_cleanup_actions as the action. */
1018 x
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
1019 x
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (x
),
1021 finally
= lower_eh_must_not_throw (outer_state
, x
);
1023 /* Drop all of this into the exception sequence. */
1024 emit_post_landing_pad (&eh_seq
, tf
->region
);
1025 gimple_seq_add_seq (&eh_seq
, finally
);
1026 if (finally_may_fallthru
)
1027 emit_resx (&eh_seq
, tf
->region
);
1029 /* Having now been handled, EH isn't to be considered with
1030 the rest of the outgoing edges. */
1031 tf
->may_throw
= false;
1034 /* A subroutine of lower_try_finally. We have determined that there is
1035 no fallthru edge out of the finally block. This means that there is
1036 no outgoing edge corresponding to any incoming edge. Restructure the
1037 try_finally node for this special case. */
1040 lower_try_finally_nofallthru (struct leh_state
*state
,
1041 struct leh_tf_state
*tf
)
1043 tree lab
, return_val
;
1046 struct goto_queue_node
*q
, *qe
;
1048 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1050 /* We expect that tf->top_p is a GIMPLE_TRY. */
1051 finally
= gimple_try_cleanup (tf
->top_p
);
1052 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1054 x
= gimple_build_label (lab
);
1055 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1059 qe
= q
+ tf
->goto_queue_active
;
1062 do_return_redirection (q
, lab
, NULL
, &return_val
);
1064 do_goto_redirection (q
, lab
, NULL
, tf
);
1066 replace_goto_queue (tf
);
1068 lower_eh_constructs_1 (state
, finally
);
1069 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1073 emit_post_landing_pad (&eh_seq
, tf
->region
);
1075 x
= gimple_build_goto (lab
);
1076 gimple_seq_add_stmt (&eh_seq
, x
);
1080 /* A subroutine of lower_try_finally. We have determined that there is
1081 exactly one destination of the finally block. Restructure the
1082 try_finally node for this special case. */
1085 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1087 struct goto_queue_node
*q
, *qe
;
1091 location_t loc
= gimple_location (tf
->try_finally_expr
);
1093 finally
= gimple_try_cleanup (tf
->top_p
);
1094 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1096 lower_eh_constructs_1 (state
, finally
);
1100 /* Only reachable via the exception edge. Add the given label to
1101 the head of the FINALLY block. Append a RESX at the end. */
1102 emit_post_landing_pad (&eh_seq
, tf
->region
);
1103 gimple_seq_add_seq (&eh_seq
, finally
);
1104 emit_resx (&eh_seq
, tf
->region
);
1108 if (tf
->may_fallthru
)
1110 /* Only reachable via the fallthru edge. Do nothing but let
1111 the two blocks run together; we'll fall out the bottom. */
1112 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1116 finally_label
= create_artificial_label (loc
);
1117 x
= gimple_build_label (finally_label
);
1118 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1120 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1123 qe
= q
+ tf
->goto_queue_active
;
1127 /* Reachable by return expressions only. Redirect them. */
1128 tree return_val
= NULL
;
1130 do_return_redirection (q
, finally_label
, NULL
, &return_val
);
1131 replace_goto_queue (tf
);
1135 /* Reachable by goto expressions only. Redirect them. */
1137 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1138 replace_goto_queue (tf
);
1140 if (VEC_index (tree
, tf
->dest_array
, 0) == tf
->fallthru_label
)
1142 /* Reachable by goto to fallthru label only. Redirect it
1143 to the new label (already created, sadly), and do not
1144 emit the final branch out, or the fallthru label. */
1145 tf
->fallthru_label
= NULL
;
1150 /* Place the original return/goto to the original destination
1151 immediately after the finally block. */
1152 x
= tf
->goto_queue
[0].cont_stmt
;
1153 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1154 maybe_record_in_goto_queue (state
, x
);
1157 /* A subroutine of lower_try_finally. There are multiple edges incoming
1158 and outgoing from the finally block. Implement this by duplicating the
1159 finally block for every destination. */
1162 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1165 gimple_seq new_stmt
;
1169 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1171 finally
= gimple_try_cleanup (tf
->top_p
);
1172 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1175 if (tf
->may_fallthru
)
1177 seq
= lower_try_finally_dup_block (finally
, state
);
1178 lower_eh_constructs_1 (state
, seq
);
1179 gimple_seq_add_seq (&new_stmt
, seq
);
1181 tmp
= lower_try_finally_fallthru_label (tf
);
1182 x
= gimple_build_goto (tmp
);
1183 gimple_seq_add_stmt (&new_stmt
, x
);
1188 seq
= lower_try_finally_dup_block (finally
, state
);
1189 lower_eh_constructs_1 (state
, seq
);
1191 emit_post_landing_pad (&eh_seq
, tf
->region
);
1192 gimple_seq_add_seq (&eh_seq
, seq
);
1193 emit_resx (&eh_seq
, tf
->region
);
1198 struct goto_queue_node
*q
, *qe
;
1199 tree return_val
= NULL
;
1200 int return_index
, index
;
1203 struct goto_queue_node
*q
;
1207 return_index
= VEC_length (tree
, tf
->dest_array
);
1208 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1211 qe
= q
+ tf
->goto_queue_active
;
1214 index
= q
->index
< 0 ? return_index
: q
->index
;
1216 if (!labels
[index
].q
)
1217 labels
[index
].q
= q
;
1220 for (index
= 0; index
< return_index
+ 1; index
++)
1224 q
= labels
[index
].q
;
1228 lab
= labels
[index
].label
1229 = create_artificial_label (tf_loc
);
1231 if (index
== return_index
)
1232 do_return_redirection (q
, lab
, NULL
, &return_val
);
1234 do_goto_redirection (q
, lab
, NULL
, tf
);
1236 x
= gimple_build_label (lab
);
1237 gimple_seq_add_stmt (&new_stmt
, x
);
1239 seq
= lower_try_finally_dup_block (finally
, state
);
1240 lower_eh_constructs_1 (state
, seq
);
1241 gimple_seq_add_seq (&new_stmt
, seq
);
1243 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1244 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1247 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1251 index
= q
->index
< 0 ? return_index
: q
->index
;
1253 if (labels
[index
].q
== q
)
1256 lab
= labels
[index
].label
;
1258 if (index
== return_index
)
1259 do_return_redirection (q
, lab
, NULL
, &return_val
);
1261 do_goto_redirection (q
, lab
, NULL
, tf
);
1264 replace_goto_queue (tf
);
1268 /* Need to link new stmts after running replace_goto_queue due
1269 to not wanting to process the same goto stmts twice. */
1270 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1273 /* A subroutine of lower_try_finally. There are multiple edges incoming
1274 and outgoing from the finally block. Implement this by instrumenting
1275 each incoming edge and creating a switch statement at the end of the
1276 finally block that branches to the appropriate destination. */
1279 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1281 struct goto_queue_node
*q
, *qe
;
1282 tree return_val
= NULL
;
1283 tree finally_tmp
, finally_label
;
1284 int return_index
, eh_index
, fallthru_index
;
1285 int nlabels
, ndests
, j
, last_case_index
;
1287 VEC (tree
,heap
) *case_label_vec
;
1288 gimple_seq switch_body
;
1293 struct pointer_map_t
*cont_map
= NULL
;
1294 /* The location of the TRY_FINALLY stmt. */
1295 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1296 /* The location of the finally block. */
1297 location_t finally_loc
;
1299 switch_body
= gimple_seq_alloc ();
1301 /* Mash the TRY block to the head of the chain. */
1302 finally
= gimple_try_cleanup (tf
->top_p
);
1303 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1305 /* The location of the finally is either the last stmt in the finally
1306 block or the location of the TRY_FINALLY itself. */
1307 finally_loc
= gimple_seq_last_stmt (tf
->top_p_seq
) != NULL
?
1308 gimple_location (gimple_seq_last_stmt (tf
->top_p_seq
))
1311 /* Lower the finally block itself. */
1312 lower_eh_constructs_1 (state
, finally
);
1314 /* Prepare for switch statement generation. */
1315 nlabels
= VEC_length (tree
, tf
->dest_array
);
1316 return_index
= nlabels
;
1317 eh_index
= return_index
+ tf
->may_return
;
1318 fallthru_index
= eh_index
+ tf
->may_throw
;
1319 ndests
= fallthru_index
+ tf
->may_fallthru
;
1321 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1322 finally_label
= create_artificial_label (finally_loc
);
1324 /* We use VEC_quick_push on case_label_vec throughout this function,
1325 since we know the size in advance and allocate precisely as muce
1327 case_label_vec
= VEC_alloc (tree
, heap
, ndests
);
1329 last_case_index
= 0;
1331 /* Begin inserting code for getting to the finally block. Things
1332 are done in this order to correspond to the sequence the code is
1335 if (tf
->may_fallthru
)
1337 x
= gimple_build_assign (finally_tmp
,
1338 build_int_cst (NULL
, fallthru_index
));
1339 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1341 last_case
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1342 build_int_cst (NULL
, fallthru_index
),
1343 NULL
, create_artificial_label (tf_loc
));
1344 VEC_quick_push (tree
, case_label_vec
, last_case
);
1347 x
= gimple_build_label (CASE_LABEL (last_case
));
1348 gimple_seq_add_stmt (&switch_body
, x
);
1350 tmp
= lower_try_finally_fallthru_label (tf
);
1351 x
= gimple_build_goto (tmp
);
1352 gimple_seq_add_stmt (&switch_body
, x
);
1357 emit_post_landing_pad (&eh_seq
, tf
->region
);
1359 x
= gimple_build_assign (finally_tmp
,
1360 build_int_cst (NULL
, eh_index
));
1361 gimple_seq_add_stmt (&eh_seq
, x
);
1363 x
= gimple_build_goto (finally_label
);
1364 gimple_seq_add_stmt (&eh_seq
, x
);
1366 last_case
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1367 build_int_cst (NULL
, eh_index
),
1368 NULL
, create_artificial_label (tf_loc
));
1369 VEC_quick_push (tree
, case_label_vec
, last_case
);
1372 x
= gimple_build_label (CASE_LABEL (last_case
));
1373 gimple_seq_add_stmt (&eh_seq
, x
);
1374 emit_resx (&eh_seq
, tf
->region
);
1377 x
= gimple_build_label (finally_label
);
1378 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1380 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1382 /* Redirect each incoming goto edge. */
1384 qe
= q
+ tf
->goto_queue_active
;
1385 j
= last_case_index
+ tf
->may_return
;
1386 /* Prepare the assignments to finally_tmp that are executed upon the
1387 entrance through a particular edge. */
1392 unsigned int case_index
;
1394 mod
= gimple_seq_alloc ();
1398 x
= gimple_build_assign (finally_tmp
,
1399 build_int_cst (NULL
, return_index
));
1400 gimple_seq_add_stmt (&mod
, x
);
1401 do_return_redirection (q
, finally_label
, mod
, &return_val
);
1402 switch_id
= return_index
;
1406 x
= gimple_build_assign (finally_tmp
,
1407 build_int_cst (NULL
, q
->index
));
1408 gimple_seq_add_stmt (&mod
, x
);
1409 do_goto_redirection (q
, finally_label
, mod
, tf
);
1410 switch_id
= q
->index
;
1413 case_index
= j
+ q
->index
;
1414 if (VEC_length (tree
, case_label_vec
) <= case_index
1415 || !VEC_index (tree
, case_label_vec
, case_index
))
1419 case_lab
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1420 build_int_cst (NULL
, switch_id
),
1422 /* We store the cont_stmt in the pointer map, so that we can recover
1423 it in the loop below. We don't create the new label while
1424 walking the goto_queue because pointers don't offer a stable
1427 cont_map
= pointer_map_create ();
1428 slot
= pointer_map_insert (cont_map
, case_lab
);
1429 *slot
= q
->cont_stmt
;
1430 VEC_quick_push (tree
, case_label_vec
, case_lab
);
1433 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1439 last_case
= VEC_index (tree
, case_label_vec
, j
);
1441 gcc_assert (last_case
);
1442 gcc_assert (cont_map
);
1444 slot
= pointer_map_contains (cont_map
, last_case
);
1445 /* As the comment above suggests, CASE_LABEL (last_case) was just a
1446 placeholder, it does not store an actual label, yet. */
1448 cont_stmt
= *(gimple
*) slot
;
1450 label
= create_artificial_label (tf_loc
);
1451 CASE_LABEL (last_case
) = label
;
1453 x
= gimple_build_label (label
);
1454 gimple_seq_add_stmt (&switch_body
, x
);
1455 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1456 maybe_record_in_goto_queue (state
, cont_stmt
);
1459 pointer_map_destroy (cont_map
);
1461 replace_goto_queue (tf
);
1463 /* Make sure that the last case is the default label, as one is required.
1464 Then sort the labels, which is also required in GIMPLE. */
1465 CASE_LOW (last_case
) = NULL
;
1466 sort_case_labels (case_label_vec
);
1468 /* Build the switch statement, setting last_case to be the default
1470 switch_stmt
= gimple_build_switch_vec (finally_tmp
, last_case
,
1472 gimple_set_location (switch_stmt
, finally_loc
);
1474 /* Need to link SWITCH_STMT after running replace_goto_queue
1475 due to not wanting to process the same goto stmts twice. */
1476 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1477 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1480 /* Decide whether or not we are going to duplicate the finally block.
1481 There are several considerations.
1483 First, if this is Java, then the finally block contains code
1484 written by the user. It has line numbers associated with it,
1485 so duplicating the block means it's difficult to set a breakpoint.
1486 Since controlling code generation via -g is verboten, we simply
1487 never duplicate code without optimization.
1489 Second, we'd like to prevent egregious code growth. One way to
1490 do this is to estimate the size of the finally block, multiply
1491 that by the number of copies we'd need to make, and compare against
1492 the estimate of the size of the switch machinery we'd have to add. */
1495 decide_copy_try_finally (int ndests
, gimple_seq finally
)
1497 int f_estimate
, sw_estimate
;
1502 /* Finally estimate N times, plus N gotos. */
1503 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1504 f_estimate
= (f_estimate
+ 1) * ndests
;
1506 /* Switch statement (cost 10), N variable assignments, N gotos. */
1507 sw_estimate
= 10 + 2 * ndests
;
1509 /* Optimize for size clearly wants our best guess. */
1510 if (optimize_function_for_size_p (cfun
))
1511 return f_estimate
< sw_estimate
;
1513 /* ??? These numbers are completely made up so far. */
1515 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1517 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1520 /* REG is the enclosing region for a possible cleanup region, or the region
1521 itself. Returns TRUE if such a region would be unreachable.
1523 Cleanup regions within a must-not-throw region aren't actually reachable
1524 even if there are throwing stmts within them, because the personality
1525 routine will call terminate before unwinding. */
1528 cleanup_is_dead_in (eh_region reg
)
1530 while (reg
&& reg
->type
== ERT_CLEANUP
)
1532 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1535 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1536 to a sequence of labels and blocks, plus the exception region trees
1537 that record all the magic. This is complicated by the need to
1538 arrange for the FINALLY block to be executed on all exits. */
1541 lower_try_finally (struct leh_state
*state
, gimple tp
)
1543 struct leh_tf_state this_tf
;
1544 struct leh_state this_state
;
1546 gimple_seq old_eh_seq
;
1548 /* Process the try block. */
1550 memset (&this_tf
, 0, sizeof (this_tf
));
1551 this_tf
.try_finally_expr
= tp
;
1553 this_tf
.outer
= state
;
1554 if (using_eh_for_cleanups_p
&& !cleanup_is_dead_in (state
->cur_region
))
1556 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1557 this_state
.cur_region
= this_tf
.region
;
1561 this_tf
.region
= NULL
;
1562 this_state
.cur_region
= state
->cur_region
;
1565 this_state
.ehp_region
= state
->ehp_region
;
1566 this_state
.tf
= &this_tf
;
1568 old_eh_seq
= eh_seq
;
1571 lower_eh_constructs_1 (&this_state
, gimple_try_eval(tp
));
1573 /* Determine if the try block is escaped through the bottom. */
1574 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1576 /* Determine if any exceptions are possible within the try block. */
1578 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1579 if (this_tf
.may_throw
)
1580 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1582 /* Determine how many edges (still) reach the finally block. Or rather,
1583 how many destinations are reached by the finally block. Use this to
1584 determine how we process the finally block itself. */
1586 ndests
= VEC_length (tree
, this_tf
.dest_array
);
1587 ndests
+= this_tf
.may_fallthru
;
1588 ndests
+= this_tf
.may_return
;
1589 ndests
+= this_tf
.may_throw
;
1591 /* If the FINALLY block is not reachable, dike it out. */
1594 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1595 gimple_try_set_cleanup (tp
, NULL
);
1597 /* If the finally block doesn't fall through, then any destination
1598 we might try to impose there isn't reached either. There may be
1599 some minor amount of cleanup and redirection still needed. */
1600 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1601 lower_try_finally_nofallthru (state
, &this_tf
);
1603 /* We can easily special-case redirection to a single destination. */
1604 else if (ndests
== 1)
1605 lower_try_finally_onedest (state
, &this_tf
);
1606 else if (decide_copy_try_finally (ndests
, gimple_try_cleanup (tp
)))
1607 lower_try_finally_copy (state
, &this_tf
);
1609 lower_try_finally_switch (state
, &this_tf
);
1611 /* If someone requested we add a label at the end of the transformed
1613 if (this_tf
.fallthru_label
)
1615 /* This must be reached only if ndests == 0. */
1616 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1617 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1620 VEC_free (tree
, heap
, this_tf
.dest_array
);
1621 if (this_tf
.goto_queue
)
1622 free (this_tf
.goto_queue
);
1623 if (this_tf
.goto_queue_map
)
1624 pointer_map_destroy (this_tf
.goto_queue_map
);
1626 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1627 If there was no old eh_seq, then the append is trivially already done. */
1631 eh_seq
= old_eh_seq
;
1634 gimple_seq new_eh_seq
= eh_seq
;
1635 eh_seq
= old_eh_seq
;
1636 gimple_seq_add_seq(&eh_seq
, new_eh_seq
);
1640 return this_tf
.top_p_seq
;
1643 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1644 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1645 exception region trees that records all the magic. */
1648 lower_catch (struct leh_state
*state
, gimple tp
)
1650 eh_region try_region
= NULL
;
1651 struct leh_state this_state
= *state
;
1652 gimple_stmt_iterator gsi
;
1656 location_t try_catch_loc
= gimple_location (tp
);
1658 if (flag_exceptions
)
1660 try_region
= gen_eh_region_try (state
->cur_region
);
1661 this_state
.cur_region
= try_region
;
1664 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1666 if (!eh_region_may_contain_throw (try_region
))
1667 return gimple_try_eval (tp
);
1670 emit_eh_dispatch (&new_seq
, try_region
);
1671 emit_resx (&new_seq
, try_region
);
1673 this_state
.cur_region
= state
->cur_region
;
1674 this_state
.ehp_region
= try_region
;
1677 for (gsi
= gsi_start (gimple_try_cleanup (tp
));
1685 gcatch
= gsi_stmt (gsi
);
1686 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1688 handler
= gimple_catch_handler (gcatch
);
1689 lower_eh_constructs_1 (&this_state
, handler
);
1691 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1692 x
= gimple_build_label (c
->label
);
1693 gimple_seq_add_stmt (&new_seq
, x
);
1695 gimple_seq_add_seq (&new_seq
, handler
);
1697 if (gimple_seq_may_fallthru (new_seq
))
1700 out_label
= create_artificial_label (try_catch_loc
);
1702 x
= gimple_build_goto (out_label
);
1703 gimple_seq_add_stmt (&new_seq
, x
);
1709 gimple_try_set_cleanup (tp
, new_seq
);
1711 return frob_into_branch_around (tp
, try_region
, out_label
);
1714 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1715 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1716 region trees that record all the magic. */
1719 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1721 struct leh_state this_state
= *state
;
1722 eh_region this_region
= NULL
;
1726 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1728 if (flag_exceptions
)
1730 this_region
= gen_eh_region_allowed (state
->cur_region
,
1731 gimple_eh_filter_types (inner
));
1732 this_state
.cur_region
= this_region
;
1735 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1737 if (!eh_region_may_contain_throw (this_region
))
1738 return gimple_try_eval (tp
);
1741 this_state
.cur_region
= state
->cur_region
;
1742 this_state
.ehp_region
= this_region
;
1744 emit_eh_dispatch (&new_seq
, this_region
);
1745 emit_resx (&new_seq
, this_region
);
1747 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1748 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1749 gimple_seq_add_stmt (&new_seq
, x
);
1751 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure (inner
));
1752 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1754 gimple_try_set_cleanup (tp
, new_seq
);
1756 return frob_into_branch_around (tp
, this_region
, NULL
);
1759 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1760 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1761 plus the exception region trees that record all the magic. */
1764 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1766 struct leh_state this_state
= *state
;
1768 if (flag_exceptions
)
1770 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1771 eh_region this_region
;
1773 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1774 this_region
->u
.must_not_throw
.failure_decl
1775 = gimple_eh_must_not_throw_fndecl (inner
);
1776 this_region
->u
.must_not_throw
.failure_loc
= gimple_location (tp
);
1778 /* In order to get mangling applied to this decl, we must mark it
1779 used now. Otherwise, pass_ipa_free_lang_data won't think it
1781 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1783 this_state
.cur_region
= this_region
;
1786 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1788 return gimple_try_eval (tp
);
1791 /* Implement a cleanup expression. This is similar to try-finally,
1792 except that we only execute the cleanup block for exception edges. */
1795 lower_cleanup (struct leh_state
*state
, gimple tp
)
1797 struct leh_state this_state
= *state
;
1798 eh_region this_region
= NULL
;
1799 struct leh_tf_state fake_tf
;
1801 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1803 if (flag_exceptions
&& !cleanup_dead
)
1805 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1806 this_state
.cur_region
= this_region
;
1809 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1811 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1812 return gimple_try_eval (tp
);
1814 /* Build enough of a try-finally state so that we can reuse
1815 honor_protect_cleanup_actions. */
1816 memset (&fake_tf
, 0, sizeof (fake_tf
));
1817 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1818 fake_tf
.outer
= state
;
1819 fake_tf
.region
= this_region
;
1820 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1821 fake_tf
.may_throw
= true;
1823 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1825 if (fake_tf
.may_throw
)
1827 /* In this case honor_protect_cleanup_actions had nothing to do,
1828 and we should process this normally. */
1829 lower_eh_constructs_1 (state
, gimple_try_cleanup (tp
));
1830 result
= frob_into_branch_around (tp
, this_region
,
1831 fake_tf
.fallthru_label
);
1835 /* In this case honor_protect_cleanup_actions did nearly all of
1836 the work. All we have left is to append the fallthru_label. */
1838 result
= gimple_try_eval (tp
);
1839 if (fake_tf
.fallthru_label
)
1841 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1842 gimple_seq_add_stmt (&result
, x
);
1848 /* Main loop for lowering eh constructs. Also moves gsi to the next
1852 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1856 gimple stmt
= gsi_stmt (*gsi
);
1858 switch (gimple_code (stmt
))
1862 tree fndecl
= gimple_call_fndecl (stmt
);
1865 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1866 switch (DECL_FUNCTION_CODE (fndecl
))
1868 case BUILT_IN_EH_POINTER
:
1869 /* The front end may have generated a call to
1870 __builtin_eh_pointer (0) within a catch region. Replace
1871 this zero argument with the current catch region number. */
1872 if (state
->ehp_region
)
1874 tree nr
= build_int_cst (NULL
, state
->ehp_region
->index
);
1875 gimple_call_set_arg (stmt
, 0, nr
);
1879 /* The user has dome something silly. Remove it. */
1880 rhs
= build_int_cst (ptr_type_node
, 0);
1885 case BUILT_IN_EH_FILTER
:
1886 /* ??? This should never appear, but since it's a builtin it
1887 is accessible to abuse by users. Just remove it and
1888 replace the use with the arbitrary value zero. */
1889 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
1891 lhs
= gimple_call_lhs (stmt
);
1892 x
= gimple_build_assign (lhs
, rhs
);
1893 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
1896 case BUILT_IN_EH_COPY_VALUES
:
1897 /* Likewise this should not appear. Remove it. */
1898 gsi_remove (gsi
, true);
1908 /* If the stmt can throw use a new temporary for the assignment
1909 to a LHS. This makes sure the old value of the LHS is
1910 available on the EH edge. Only do so for statements that
1911 potentially fall thru (no noreturn calls e.g.), otherwise
1912 this new assignment might create fake fallthru regions. */
1913 if (stmt_could_throw_p (stmt
)
1914 && gimple_has_lhs (stmt
)
1915 && gimple_stmt_may_fallthru (stmt
)
1916 && !tree_could_throw_p (gimple_get_lhs (stmt
))
1917 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
1919 tree lhs
= gimple_get_lhs (stmt
);
1920 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
1921 gimple s
= gimple_build_assign (lhs
, tmp
);
1922 gimple_set_location (s
, gimple_location (stmt
));
1923 gimple_set_block (s
, gimple_block (stmt
));
1924 gimple_set_lhs (stmt
, tmp
);
1925 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
1926 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
1927 DECL_GIMPLE_REG_P (tmp
) = 1;
1928 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
1930 /* Look for things that can throw exceptions, and record them. */
1931 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
1933 record_stmt_eh_region (state
->cur_region
, stmt
);
1934 note_eh_region_may_contain_throw (state
->cur_region
);
1941 maybe_record_in_goto_queue (state
, stmt
);
1945 verify_norecord_switch_expr (state
, stmt
);
1949 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
1950 replace
= lower_try_finally (state
, stmt
);
1953 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
1956 replace
= gimple_try_eval (stmt
);
1957 lower_eh_constructs_1 (state
, replace
);
1960 switch (gimple_code (x
))
1963 replace
= lower_catch (state
, stmt
);
1965 case GIMPLE_EH_FILTER
:
1966 replace
= lower_eh_filter (state
, stmt
);
1968 case GIMPLE_EH_MUST_NOT_THROW
:
1969 replace
= lower_eh_must_not_throw (state
, stmt
);
1972 replace
= lower_cleanup (state
, stmt
);
1977 /* Remove the old stmt and insert the transformed sequence
1979 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
1980 gsi_remove (gsi
, true);
1982 /* Return since we don't want gsi_next () */
1986 /* A type, a decl, or some kind of statement that we're not
1987 interested in. Don't walk them. */
1994 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
1997 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
)
1999 gimple_stmt_iterator gsi
;
2000 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
);)
2001 lower_eh_constructs_2 (state
, &gsi
);
2005 lower_eh_constructs (void)
2007 struct leh_state null_state
;
2010 bodyp
= gimple_body (current_function_decl
);
2014 finally_tree
= htab_create (31, struct_ptr_hash
, struct_ptr_eq
, free
);
2015 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2016 memset (&null_state
, 0, sizeof (null_state
));
2018 collect_finally_tree_1 (bodyp
, NULL
);
2019 lower_eh_constructs_1 (&null_state
, bodyp
);
2021 /* We assume there's a return statement, or something, at the end of
2022 the function, and thus ploping the EH sequence afterward won't
2024 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2025 gimple_seq_add_seq (&bodyp
, eh_seq
);
2027 /* We assume that since BODYP already existed, adding EH_SEQ to it
2028 didn't change its value, and we don't have to re-set the function. */
2029 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2031 htab_delete (finally_tree
);
2032 BITMAP_FREE (eh_region_may_contain_throw_map
);
2035 /* If this function needs a language specific EH personality routine
2036 and the frontend didn't already set one do so now. */
2037 if (function_needs_eh_personality (cfun
) == eh_personality_lang
2038 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2039 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2040 = lang_hooks
.eh_personality ();
2045 struct gimple_opt_pass pass_lower_eh
=
2051 lower_eh_constructs
, /* execute */
2054 0, /* static_pass_number */
2055 TV_TREE_EH
, /* tv_id */
2056 PROP_gimple_lcf
, /* properties_required */
2057 PROP_gimple_leh
, /* properties_provided */
2058 0, /* properties_destroyed */
2059 0, /* todo_flags_start */
2060 TODO_dump_func
/* todo_flags_finish */
2064 /* Create the multiple edges from an EH_DISPATCH statement to all of
2065 the possible handlers for its EH region. Return true if there's
2066 no fallthru edge; false if there is. */
2069 make_eh_dispatch_edges (gimple stmt
)
2073 basic_block src
, dst
;
2075 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2076 src
= gimple_bb (stmt
);
2081 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2083 dst
= label_to_block (c
->label
);
2084 make_edge (src
, dst
, 0);
2086 /* A catch-all handler doesn't have a fallthru. */
2087 if (c
->type_list
== NULL
)
2092 case ERT_ALLOWED_EXCEPTIONS
:
2093 dst
= label_to_block (r
->u
.allowed
.label
);
2094 make_edge (src
, dst
, 0);
2104 /* Create the single EH edge from STMT to its nearest landing pad,
2105 if there is such a landing pad within the current function. */
2108 make_eh_edges (gimple stmt
)
2110 basic_block src
, dst
;
2114 lp_nr
= lookup_stmt_eh_lp (stmt
);
2118 lp
= get_eh_landing_pad_from_number (lp_nr
);
2119 gcc_assert (lp
!= NULL
);
2121 src
= gimple_bb (stmt
);
2122 dst
= label_to_block (lp
->post_landing_pad
);
2123 make_edge (src
, dst
, EDGE_EH
);
2126 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2127 do not actually perform the final edge redirection.
2129 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2130 we intend to change the destination EH region as well; this means
2131 EH_LANDING_PAD_NR must already be set on the destination block label.
2132 If false, we're being called from generic cfg manipulation code and we
2133 should preserve our place within the region tree. */
2136 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2138 eh_landing_pad old_lp
, new_lp
;
2141 int old_lp_nr
, new_lp_nr
;
2142 tree old_label
, new_label
;
2146 old_bb
= edge_in
->dest
;
2147 old_label
= gimple_block_label (old_bb
);
2148 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2149 gcc_assert (old_lp_nr
> 0);
2150 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2152 throw_stmt
= last_stmt (edge_in
->src
);
2153 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2155 new_label
= gimple_block_label (new_bb
);
2157 /* Look for an existing region that might be using NEW_BB already. */
2158 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2161 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2162 gcc_assert (new_lp
);
2164 /* Unless CHANGE_REGION is true, the new and old landing pad
2165 had better be associated with the same EH region. */
2166 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2171 gcc_assert (!change_region
);
2174 /* Notice when we redirect the last EH edge away from OLD_BB. */
2175 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2176 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2181 /* NEW_LP already exists. If there are still edges into OLD_LP,
2182 there's nothing to do with the EH tree. If there are no more
2183 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2184 If CHANGE_REGION is true, then our caller is expecting to remove
2186 if (e
== NULL
&& !change_region
)
2187 remove_eh_landing_pad (old_lp
);
2191 /* No correct landing pad exists. If there are no more edges
2192 into OLD_LP, then we can simply re-use the existing landing pad.
2193 Otherwise, we have to create a new landing pad. */
2196 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2200 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2201 new_lp
->post_landing_pad
= new_label
;
2202 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2205 /* Maybe move the throwing statement to the new region. */
2206 if (old_lp
!= new_lp
)
2208 remove_stmt_from_eh_lp (throw_stmt
);
2209 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2213 /* Redirect EH edge E to NEW_BB. */
2216 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2218 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2219 return ssa_redirect_edge (edge_in
, new_bb
);
2222 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2223 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2224 The actual edge update will happen in the caller. */
2227 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2229 tree new_lab
= gimple_block_label (new_bb
);
2230 bool any_changed
= false;
2235 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2239 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2241 old_bb
= label_to_block (c
->label
);
2242 if (old_bb
== e
->dest
)
2250 case ERT_ALLOWED_EXCEPTIONS
:
2251 old_bb
= label_to_block (r
->u
.allowed
.label
);
2252 gcc_assert (old_bb
== e
->dest
);
2253 r
->u
.allowed
.label
= new_lab
;
2261 gcc_assert (any_changed
);
2264 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2267 operation_could_trap_helper_p (enum tree_code op
,
2278 case TRUNC_DIV_EXPR
:
2280 case FLOOR_DIV_EXPR
:
2281 case ROUND_DIV_EXPR
:
2282 case EXACT_DIV_EXPR
:
2284 case FLOOR_MOD_EXPR
:
2285 case ROUND_MOD_EXPR
:
2286 case TRUNC_MOD_EXPR
:
2288 if (honor_snans
|| honor_trapv
)
2291 return flag_trapping_math
;
2292 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2301 /* Some floating point comparisons may trap. */
2306 case UNORDERED_EXPR
:
2316 case FIX_TRUNC_EXPR
:
2317 /* Conversion of floating point might trap. */
2323 /* These operations don't trap with floating point. */
2331 /* Any floating arithmetic may trap. */
2332 if (fp_operation
&& flag_trapping_math
)
2339 /* Any floating arithmetic may trap. */
2340 if (fp_operation
&& flag_trapping_math
)
2348 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2349 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2350 type operands that may trap. If OP is a division operator, DIVISOR contains
2351 the value of the divisor. */
2354 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2357 bool honor_nans
= (fp_operation
&& flag_trapping_math
2358 && !flag_finite_math_only
);
2359 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2362 if (TREE_CODE_CLASS (op
) != tcc_comparison
2363 && TREE_CODE_CLASS (op
) != tcc_unary
2364 && TREE_CODE_CLASS (op
) != tcc_binary
)
2367 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2368 honor_nans
, honor_snans
, divisor
,
2372 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2373 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2374 This routine expects only GIMPLE lhs or rhs input. */
2377 tree_could_trap_p (tree expr
)
2379 enum tree_code code
;
2380 bool fp_operation
= false;
2381 bool honor_trapv
= false;
2382 tree t
, base
, div
= NULL_TREE
;
2387 code
= TREE_CODE (expr
);
2388 t
= TREE_TYPE (expr
);
2392 if (COMPARISON_CLASS_P (expr
))
2393 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2395 fp_operation
= FLOAT_TYPE_P (t
);
2396 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2399 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2400 div
= TREE_OPERAND (expr
, 1);
2401 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2407 case TARGET_MEM_REF
:
2408 /* For TARGET_MEM_REFs use the information based on the original
2410 expr
= TMR_ORIGINAL (expr
);
2411 code
= TREE_CODE (expr
);
2418 case VIEW_CONVERT_EXPR
:
2419 case WITH_SIZE_EXPR
:
2420 expr
= TREE_OPERAND (expr
, 0);
2421 code
= TREE_CODE (expr
);
2424 case ARRAY_RANGE_REF
:
2425 base
= TREE_OPERAND (expr
, 0);
2426 if (tree_could_trap_p (base
))
2428 if (TREE_THIS_NOTRAP (expr
))
2430 return !range_in_array_bounds_p (expr
);
2433 base
= TREE_OPERAND (expr
, 0);
2434 if (tree_could_trap_p (base
))
2436 if (TREE_THIS_NOTRAP (expr
))
2438 return !in_array_bounds_p (expr
);
2441 case ALIGN_INDIRECT_REF
:
2442 case MISALIGNED_INDIRECT_REF
:
2443 return !TREE_THIS_NOTRAP (expr
);
2446 return TREE_THIS_VOLATILE (expr
);
2449 t
= get_callee_fndecl (expr
);
2450 /* Assume that calls to weak functions may trap. */
2451 if (!t
|| !DECL_P (t
) || DECL_WEAK (t
))
2461 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2462 an assignment or a conditional) may throw. */
2465 stmt_could_throw_1_p (gimple stmt
)
2467 enum tree_code code
= gimple_expr_code (stmt
);
2468 bool honor_nans
= false;
2469 bool honor_snans
= false;
2470 bool fp_operation
= false;
2471 bool honor_trapv
= false;
2476 if (TREE_CODE_CLASS (code
) == tcc_comparison
2477 || TREE_CODE_CLASS (code
) == tcc_unary
2478 || TREE_CODE_CLASS (code
) == tcc_binary
)
2480 t
= gimple_expr_type (stmt
);
2481 fp_operation
= FLOAT_TYPE_P (t
);
2484 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2485 honor_snans
= flag_signaling_nans
!= 0;
2487 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2491 /* Check if the main expression may trap. */
2492 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2493 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2494 honor_nans
, honor_snans
, t
,
2499 /* If the expression does not trap, see if any of the individual operands may
2501 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2502 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2509 /* Return true if statement STMT could throw an exception. */
2512 stmt_could_throw_p (gimple stmt
)
2514 if (!flag_exceptions
)
2517 /* The only statements that can throw an exception are assignments,
2518 conditionals, calls, resx, and asms. */
2519 switch (gimple_code (stmt
))
2525 return !gimple_call_nothrow_p (stmt
);
2529 if (!flag_non_call_exceptions
)
2531 return stmt_could_throw_1_p (stmt
);
2534 if (!flag_non_call_exceptions
)
2536 return gimple_asm_volatile_p (stmt
);
2544 /* Return true if expression T could throw an exception. */
2547 tree_could_throw_p (tree t
)
2549 if (!flag_exceptions
)
2551 if (TREE_CODE (t
) == MODIFY_EXPR
)
2553 if (flag_non_call_exceptions
2554 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2556 t
= TREE_OPERAND (t
, 1);
2559 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2560 t
= TREE_OPERAND (t
, 0);
2561 if (TREE_CODE (t
) == CALL_EXPR
)
2562 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2563 if (flag_non_call_exceptions
)
2564 return tree_could_trap_p (t
);
2568 /* Return true if STMT can throw an exception that is not caught within
2569 the current function (CFUN). */
2572 stmt_can_throw_external (gimple stmt
)
2576 if (!stmt_could_throw_p (stmt
))
2579 lp_nr
= lookup_stmt_eh_lp (stmt
);
2583 /* Return true if STMT can throw an exception that is caught within
2584 the current function (CFUN). */
2587 stmt_can_throw_internal (gimple stmt
)
2591 if (!stmt_could_throw_p (stmt
))
2594 lp_nr
= lookup_stmt_eh_lp (stmt
);
2598 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2599 remove any entry it might have from the EH table. Return true if
2600 any change was made. */
2603 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2605 if (stmt_could_throw_p (stmt
))
2607 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2610 /* Likewise, but always use the current function. */
2613 maybe_clean_eh_stmt (gimple stmt
)
2615 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2618 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2619 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2620 in the table if it should be in there. Return TRUE if a replacement was
2621 done that my require an EH edge purge. */
2624 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2626 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2630 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2632 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2635 remove_stmt_from_eh_lp (old_stmt
);
2636 if (new_stmt_could_throw
)
2638 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2648 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2649 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2650 operand is the return value of duplicate_eh_regions. */
2653 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2654 struct function
*old_fun
, gimple old_stmt
,
2655 struct pointer_map_t
*map
, int default_lp_nr
)
2657 int old_lp_nr
, new_lp_nr
;
2660 if (!stmt_could_throw_p (new_stmt
))
2663 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2666 if (default_lp_nr
== 0)
2668 new_lp_nr
= default_lp_nr
;
2670 else if (old_lp_nr
> 0)
2672 eh_landing_pad old_lp
, new_lp
;
2674 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2675 slot
= pointer_map_contains (map
, old_lp
);
2676 new_lp
= (eh_landing_pad
) *slot
;
2677 new_lp_nr
= new_lp
->index
;
2681 eh_region old_r
, new_r
;
2683 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2684 slot
= pointer_map_contains (map
, old_r
);
2685 new_r
= (eh_region
) *slot
;
2686 new_lp_nr
= -new_r
->index
;
2689 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2693 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2694 and thus no remapping is required. */
2697 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2701 if (!stmt_could_throw_p (new_stmt
))
2704 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2708 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2712 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2713 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2714 this only handles handlers consisting of a single call, as that's the
2715 important case for C++: a destructor call for a particular object showing
2716 up in multiple handlers. */
2719 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2721 gimple_stmt_iterator gsi
;
2725 gsi
= gsi_start (oneh
);
2726 if (!gsi_one_before_end_p (gsi
))
2728 ones
= gsi_stmt (gsi
);
2730 gsi
= gsi_start (twoh
);
2731 if (!gsi_one_before_end_p (gsi
))
2733 twos
= gsi_stmt (gsi
);
2735 if (!is_gimple_call (ones
)
2736 || !is_gimple_call (twos
)
2737 || gimple_call_lhs (ones
)
2738 || gimple_call_lhs (twos
)
2739 || gimple_call_chain (ones
)
2740 || gimple_call_chain (twos
)
2741 || !operand_equal_p (gimple_call_fn (ones
), gimple_call_fn (twos
), 0)
2742 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2745 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2746 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2747 gimple_call_arg (twos
, ai
), 0))
2754 try { A() } finally { try { ~B() } catch { ~A() } }
2755 try { ... } finally { ~A() }
2757 try { A() } catch { ~B() }
2758 try { ~B() ... } finally { ~A() }
2760 This occurs frequently in C++, where A is a local variable and B is a
2761 temporary used in the initializer for A. */
2764 optimize_double_finally (gimple one
, gimple two
)
2767 gimple_stmt_iterator gsi
;
2769 gsi
= gsi_start (gimple_try_cleanup (one
));
2770 if (!gsi_one_before_end_p (gsi
))
2773 oneh
= gsi_stmt (gsi
);
2774 if (gimple_code (oneh
) != GIMPLE_TRY
2775 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2778 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2780 gimple_seq seq
= gimple_try_eval (oneh
);
2782 gimple_try_set_cleanup (one
, seq
);
2783 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2784 seq
= copy_gimple_seq_and_replace_locals (seq
);
2785 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2786 gimple_try_set_eval (two
, seq
);
2790 /* Perform EH refactoring optimizations that are simpler to do when code
2791 flow has been lowered but EH structures haven't. */
2794 refactor_eh_r (gimple_seq seq
)
2796 gimple_stmt_iterator gsi
;
2801 gsi
= gsi_start (seq
);
2805 if (gsi_end_p (gsi
))
2808 two
= gsi_stmt (gsi
);
2811 && gimple_code (one
) == GIMPLE_TRY
2812 && gimple_code (two
) == GIMPLE_TRY
2813 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2814 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2815 optimize_double_finally (one
, two
);
2817 switch (gimple_code (one
))
2820 refactor_eh_r (gimple_try_eval (one
));
2821 refactor_eh_r (gimple_try_cleanup (one
));
2824 refactor_eh_r (gimple_catch_handler (one
));
2826 case GIMPLE_EH_FILTER
:
2827 refactor_eh_r (gimple_eh_filter_failure (one
));
2842 refactor_eh_r (gimple_body (current_function_decl
));
2847 gate_refactor_eh (void)
2849 return flag_exceptions
!= 0;
2852 struct gimple_opt_pass pass_refactor_eh
=
2857 gate_refactor_eh
, /* gate */
2858 refactor_eh
, /* execute */
2861 0, /* static_pass_number */
2862 TV_TREE_EH
, /* tv_id */
2863 PROP_gimple_lcf
, /* properties_required */
2864 0, /* properties_provided */
2865 0, /* properties_destroyed */
2866 0, /* todo_flags_start */
2867 TODO_dump_func
/* todo_flags_finish */
2871 /* At the end of gimple optimization, we can lower RESX. */
2874 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2877 eh_region src_r
, dst_r
;
2878 gimple_stmt_iterator gsi
;
2883 lp_nr
= lookup_stmt_eh_lp (stmt
);
2885 dst_r
= get_eh_region_from_lp_number (lp_nr
);
2889 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
2890 gsi
= gsi_last_bb (bb
);
2894 /* We can wind up with no source region when pass_cleanup_eh shows
2895 that there are no entries into an eh region and deletes it, but
2896 then the block that contains the resx isn't removed. This can
2897 happen without optimization when the switch statement created by
2898 lower_try_finally_switch isn't simplified to remove the eh case.
2900 Resolve this by expanding the resx node to an abort. */
2902 fn
= implicit_built_in_decls
[BUILT_IN_TRAP
];
2903 x
= gimple_build_call (fn
, 0);
2904 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2906 while (EDGE_COUNT (bb
->succs
) > 0)
2907 remove_edge (EDGE_SUCC (bb
, 0));
2911 /* When we have a destination region, we resolve this by copying
2912 the excptr and filter values into place, and changing the edge
2913 to immediately after the landing pad. */
2922 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
2923 the failure decl into a new block, if needed. */
2924 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
2926 slot
= pointer_map_contains (mnt_map
, dst_r
);
2929 gimple_stmt_iterator gsi2
;
2931 new_bb
= create_empty_bb (bb
);
2932 lab
= gimple_block_label (new_bb
);
2933 gsi2
= gsi_start_bb (new_bb
);
2935 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
2936 x
= gimple_build_call (fn
, 0);
2937 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
2938 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
2940 slot
= pointer_map_insert (mnt_map
, dst_r
);
2946 new_bb
= label_to_block (lab
);
2949 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
2950 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
2951 e
->count
= bb
->count
;
2952 e
->probability
= REG_BR_PROB_BASE
;
2957 tree dst_nr
= build_int_cst (NULL
, dst_r
->index
);
2959 fn
= implicit_built_in_decls
[BUILT_IN_EH_COPY_VALUES
];
2960 src_nr
= build_int_cst (NULL
, src_r
->index
);
2961 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
2962 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2964 /* Update the flags for the outgoing edge. */
2965 e
= single_succ_edge (bb
);
2966 gcc_assert (e
->flags
& EDGE_EH
);
2967 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
2969 /* If there are no more EH users of the landing pad, delete it. */
2970 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
2971 if (e
->flags
& EDGE_EH
)
2975 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
2976 remove_eh_landing_pad (lp
);
2986 /* When we don't have a destination region, this exception escapes
2987 up the call chain. We resolve this by generating a call to the
2988 _Unwind_Resume library function. */
2990 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
2991 with no arguments for C++ and Java. Check for that. */
2992 if (src_r
->use_cxa_end_cleanup
)
2994 fn
= implicit_built_in_decls
[BUILT_IN_CXA_END_CLEANUP
];
2995 x
= gimple_build_call (fn
, 0);
2996 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3000 fn
= implicit_built_in_decls
[BUILT_IN_EH_POINTER
];
3001 src_nr
= build_int_cst (NULL
, src_r
->index
);
3002 x
= gimple_build_call (fn
, 1, src_nr
);
3003 var
= create_tmp_var (ptr_type_node
, NULL
);
3004 var
= make_ssa_name (var
, x
);
3005 gimple_call_set_lhs (x
, var
);
3006 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3008 fn
= implicit_built_in_decls
[BUILT_IN_UNWIND_RESUME
];
3009 x
= gimple_build_call (fn
, 1, var
);
3010 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3013 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3016 gsi_remove (&gsi
, true);
3022 execute_lower_resx (void)
3025 struct pointer_map_t
*mnt_map
;
3026 bool dominance_invalidated
= false;
3027 bool any_rewritten
= false;
3029 mnt_map
= pointer_map_create ();
3033 gimple last
= last_stmt (bb
);
3034 if (last
&& is_gimple_resx (last
))
3036 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3037 any_rewritten
= true;
3041 pointer_map_destroy (mnt_map
);
3043 if (dominance_invalidated
)
3045 free_dominance_info (CDI_DOMINATORS
);
3046 free_dominance_info (CDI_POST_DOMINATORS
);
3049 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3053 gate_lower_resx (void)
3055 return flag_exceptions
!= 0;
3058 struct gimple_opt_pass pass_lower_resx
=
3063 gate_lower_resx
, /* gate */
3064 execute_lower_resx
, /* execute */
3067 0, /* static_pass_number */
3068 TV_TREE_EH
, /* tv_id */
3069 PROP_gimple_lcf
, /* properties_required */
3070 0, /* properties_provided */
3071 0, /* properties_destroyed */
3072 0, /* todo_flags_start */
3073 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3078 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3079 we have found some duplicate labels and removed some edges. */
3082 lower_eh_dispatch (basic_block src
, gimple stmt
)
3084 gimple_stmt_iterator gsi
;
3089 bool redirected
= false;
3091 region_nr
= gimple_eh_dispatch_region (stmt
);
3092 r
= get_eh_region_from_number (region_nr
);
3094 gsi
= gsi_last_bb (src
);
3100 VEC (tree
, heap
) *labels
= NULL
;
3101 tree default_label
= NULL
;
3105 struct pointer_set_t
*seen_values
= pointer_set_create ();
3107 /* Collect the labels for a switch. Zero the post_landing_pad
3108 field becase we'll no longer have anything keeping these labels
3109 in existance and the optimizer will be free to merge these
3111 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3113 tree tp_node
, flt_node
, lab
= c
->label
;
3114 bool have_label
= false;
3117 tp_node
= c
->type_list
;
3118 flt_node
= c
->filter_list
;
3120 if (tp_node
== NULL
)
3122 default_label
= lab
;
3127 /* Filter out duplicate labels that arise when this handler
3128 is shadowed by an earlier one. When no labels are
3129 attached to the handler anymore, we remove
3130 the corresponding edge and then we delete unreachable
3131 blocks at the end of this pass. */
3132 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3134 tree t
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3135 TREE_VALUE (flt_node
), NULL
, lab
);
3136 VEC_safe_push (tree
, heap
, labels
, t
);
3137 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3141 tp_node
= TREE_CHAIN (tp_node
);
3142 flt_node
= TREE_CHAIN (flt_node
);
3147 remove_edge (find_edge (src
, label_to_block (lab
)));
3152 /* Clean up the edge flags. */
3153 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3155 if (e
->flags
& EDGE_FALLTHRU
)
3157 /* If there was no catch-all, use the fallthru edge. */
3158 if (default_label
== NULL
)
3159 default_label
= gimple_block_label (e
->dest
);
3160 e
->flags
&= ~EDGE_FALLTHRU
;
3163 gcc_assert (default_label
!= NULL
);
3165 /* Don't generate a switch if there's only a default case.
3166 This is common in the form of try { A; } catch (...) { B; }. */
3169 e
= single_succ_edge (src
);
3170 e
->flags
|= EDGE_FALLTHRU
;
3174 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3175 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3176 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3177 filter
= make_ssa_name (filter
, x
);
3178 gimple_call_set_lhs (x
, filter
);
3179 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3181 /* Turn the default label into a default case. */
3182 default_label
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3183 NULL
, NULL
, default_label
);
3184 sort_case_labels (labels
);
3186 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3187 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3189 VEC_free (tree
, heap
, labels
);
3191 pointer_set_destroy (seen_values
);
3195 case ERT_ALLOWED_EXCEPTIONS
:
3197 edge b_e
= BRANCH_EDGE (src
);
3198 edge f_e
= FALLTHRU_EDGE (src
);
3200 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3201 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3202 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3203 filter
= make_ssa_name (filter
, x
);
3204 gimple_call_set_lhs (x
, filter
);
3205 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3207 r
->u
.allowed
.label
= NULL
;
3208 x
= gimple_build_cond (EQ_EXPR
, filter
,
3209 build_int_cst (TREE_TYPE (filter
),
3210 r
->u
.allowed
.filter
),
3211 NULL_TREE
, NULL_TREE
);
3212 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3214 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3215 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3223 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3224 gsi_remove (&gsi
, true);
3229 execute_lower_eh_dispatch (void)
3232 bool any_rewritten
= false;
3233 bool redirected
= false;
3235 assign_filter_values ();
3239 gimple last
= last_stmt (bb
);
3240 if (last
&& gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3242 redirected
|= lower_eh_dispatch (bb
, last
);
3243 any_rewritten
= true;
3248 delete_unreachable_blocks ();
3249 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3253 gate_lower_eh_dispatch (void)
3255 return cfun
->eh
->region_tree
!= NULL
;
3258 struct gimple_opt_pass pass_lower_eh_dispatch
=
3262 "ehdisp", /* name */
3263 gate_lower_eh_dispatch
, /* gate */
3264 execute_lower_eh_dispatch
, /* execute */
3267 0, /* static_pass_number */
3268 TV_TREE_EH
, /* tv_id */
3269 PROP_gimple_lcf
, /* properties_required */
3270 0, /* properties_provided */
3271 0, /* properties_destroyed */
3272 0, /* todo_flags_start */
3273 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3277 /* Walk statements, see what regions are really referenced and remove
3278 those that are unused. */
3281 remove_unreachable_handlers (void)
3283 sbitmap r_reachable
, lp_reachable
;
3289 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3291 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3292 sbitmap_zero (r_reachable
);
3293 sbitmap_zero (lp_reachable
);
3297 gimple_stmt_iterator gsi
= gsi_start_bb (bb
);
3299 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3301 gimple stmt
= gsi_stmt (gsi
);
3302 lp_nr
= lookup_stmt_eh_lp (stmt
);
3304 /* Negative LP numbers are MUST_NOT_THROW regions which
3305 are not considered BB enders. */
3307 SET_BIT (r_reachable
, -lp_nr
);
3309 /* Positive LP numbers are real landing pads, are are BB enders. */
3312 gcc_assert (gsi_one_before_end_p (gsi
));
3313 region
= get_eh_region_from_lp_number (lp_nr
);
3314 SET_BIT (r_reachable
, region
->index
);
3315 SET_BIT (lp_reachable
, lp_nr
);
3322 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3323 dump_eh_tree (dump_file
, cfun
);
3324 fprintf (dump_file
, "Reachable regions: ");
3325 dump_sbitmap_file (dump_file
, r_reachable
);
3326 fprintf (dump_file
, "Reachable landing pads: ");
3327 dump_sbitmap_file (dump_file
, lp_reachable
);
3331 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3332 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3335 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3336 remove_eh_handler (region
);
3340 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3341 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3344 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3345 remove_eh_landing_pad (lp
);
3350 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3351 dump_eh_tree (dump_file
, cfun
);
3352 fprintf (dump_file
, "\n\n");
3355 sbitmap_free (r_reachable
);
3356 sbitmap_free (lp_reachable
);
3358 #ifdef ENABLE_CHECKING
3359 verify_eh_tree (cfun
);
3363 /* Remove regions that do not have landing pads. This assumes
3364 that remove_unreachable_handlers has already been run, and
3365 that we've just manipulated the landing pads since then. */
3368 remove_unreachable_handlers_no_lp (void)
3373 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3374 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
)
3377 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3378 remove_eh_handler (r
);
3382 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3383 optimisticaly split all sorts of edges, including EH edges. The
3384 optimization passes in between may not have needed them; if not,
3385 we should undo the split.
3387 Recognize this case by having one EH edge incoming to the BB and
3388 one normal edge outgoing; BB should be empty apart from the
3389 post_landing_pad label.
3391 Note that this is slightly different from the empty handler case
3392 handled by cleanup_empty_eh, in that the actual handler may yet
3393 have actual code but the landing pad has been separated from the
3394 handler. As such, cleanup_empty_eh relies on this transformation
3395 having been done first. */
3398 unsplit_eh (eh_landing_pad lp
)
3400 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3401 gimple_stmt_iterator gsi
;
3404 /* Quickly check the edge counts on BB for singularity. */
3405 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3407 e_in
= EDGE_PRED (bb
, 0);
3408 e_out
= EDGE_SUCC (bb
, 0);
3410 /* Input edge must be EH and output edge must be normal. */
3411 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3414 /* The block must be empty except for the labels and debug insns. */
3415 gsi
= gsi_after_labels (bb
);
3416 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3417 gsi_next_nondebug (&gsi
);
3418 if (!gsi_end_p (gsi
))
3421 /* The destination block must not already have a landing pad
3422 for a different region. */
3423 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3425 gimple stmt
= gsi_stmt (gsi
);
3429 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3431 lab
= gimple_label_label (stmt
);
3432 lp_nr
= EH_LANDING_PAD_NR (lab
);
3433 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3437 /* The new destination block must not already be a destination of
3438 the source block, lest we merge fallthru and eh edges and get
3439 all sorts of confused. */
3440 if (find_edge (e_in
->src
, e_out
->dest
))
3443 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3444 thought this should have been cleaned up by a phicprop pass, but
3445 that doesn't appear to handle virtuals. Propagate by hand. */
3446 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3448 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3450 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3451 tree lhs
= gimple_phi_result (phi
);
3452 tree rhs
= gimple_phi_arg_def (phi
, 0);
3453 use_operand_p use_p
;
3454 imm_use_iterator iter
;
3456 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3458 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3459 SET_USE (use_p
, rhs
);
3462 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3463 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3465 remove_phi_node (&gsi
, true);
3469 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3470 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3471 lp
->index
, e_out
->dest
->index
);
3473 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3474 a successor edge, humor it. But do the real CFG change with the
3475 predecessor of E_OUT in order to preserve the ordering of arguments
3476 to the PHI nodes in E_OUT->DEST. */
3477 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3478 redirect_edge_pred (e_out
, e_in
->src
);
3479 e_out
->flags
= e_in
->flags
;
3480 e_out
->probability
= e_in
->probability
;
3481 e_out
->count
= e_in
->count
;
3487 /* Examine each landing pad block and see if it matches unsplit_eh. */
3490 unsplit_all_eh (void)
3492 bool changed
= false;
3496 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3498 changed
|= unsplit_eh (lp
);
3503 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3504 to OLD_BB to NEW_BB; return true on success, false on failure.
3506 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3507 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3508 Virtual PHIs may be deleted and marked for renaming. */
3511 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3512 edge old_bb_out
, bool change_region
)
3514 gimple_stmt_iterator ngsi
, ogsi
;
3517 bitmap rename_virts
;
3518 bitmap ophi_handled
;
3520 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3521 redirect_edge_var_map_clear (e
);
3523 ophi_handled
= BITMAP_ALLOC (NULL
);
3524 rename_virts
= BITMAP_ALLOC (NULL
);
3526 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3527 for the edges we're going to move. */
3528 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3530 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3533 nresult
= gimple_phi_result (nphi
);
3534 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3536 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3537 the source ssa_name. */
3539 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3541 ophi
= gsi_stmt (ogsi
);
3542 if (gimple_phi_result (ophi
) == nop
)
3547 /* If we did find the corresponding PHI, copy those inputs. */
3550 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3551 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3556 if ((e
->flags
& EDGE_EH
) == 0)
3558 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3559 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3560 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3563 /* If we didn't find the PHI, but it's a VOP, remember to rename
3564 it later, assuming all other tests succeed. */
3565 else if (!is_gimple_reg (nresult
))
3566 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3567 /* If we didn't find the PHI, and it's a real variable, we know
3568 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3569 variable is unchanged from input to the block and we can simply
3570 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3574 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3575 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3576 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3580 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3581 we don't know what values from the other edges into NEW_BB to use. */
3582 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3584 gimple ophi
= gsi_stmt (ogsi
);
3585 tree oresult
= gimple_phi_result (ophi
);
3586 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3590 /* At this point we know that the merge will succeed. Remove the PHI
3591 nodes for the virtuals that we want to rename. */
3592 if (!bitmap_empty_p (rename_virts
))
3594 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3596 gimple nphi
= gsi_stmt (ngsi
);
3597 tree nresult
= gimple_phi_result (nphi
);
3598 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3600 mark_virtual_phi_result_for_renaming (nphi
);
3601 remove_phi_node (&ngsi
, true);
3608 /* Finally, move the edges and update the PHIs. */
3609 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3610 if (e
->flags
& EDGE_EH
)
3612 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3613 redirect_edge_succ (e
, new_bb
);
3614 flush_pending_stmts (e
);
3619 BITMAP_FREE (ophi_handled
);
3620 BITMAP_FREE (rename_virts
);
3624 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3625 redirect_edge_var_map_clear (e
);
3626 BITMAP_FREE (ophi_handled
);
3627 BITMAP_FREE (rename_virts
);
3631 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3632 old region to NEW_REGION at BB. */
3635 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3636 eh_landing_pad lp
, eh_region new_region
)
3638 gimple_stmt_iterator gsi
;
3641 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3645 lp
->region
= new_region
;
3646 lp
->next_lp
= new_region
->landing_pads
;
3647 new_region
->landing_pads
= lp
;
3649 /* Delete the RESX that was matched within the empty handler block. */
3650 gsi
= gsi_last_bb (bb
);
3651 mark_virtual_ops_for_renaming (gsi_stmt (gsi
));
3652 gsi_remove (&gsi
, true);
3654 /* Clean up E_OUT for the fallthru. */
3655 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3656 e_out
->probability
= REG_BR_PROB_BASE
;
3659 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3660 unsplitting than unsplit_eh was prepared to handle, e.g. when
3661 multiple incoming edges and phis are involved. */
3664 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3666 gimple_stmt_iterator gsi
;
3669 /* We really ought not have totally lost everything following
3670 a landing pad label. Given that BB is empty, there had better
3672 gcc_assert (e_out
!= NULL
);
3674 /* The destination block must not already have a landing pad
3675 for a different region. */
3677 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3679 gimple stmt
= gsi_stmt (gsi
);
3682 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3684 lab
= gimple_label_label (stmt
);
3685 lp_nr
= EH_LANDING_PAD_NR (lab
);
3686 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3690 /* Attempt to move the PHIs into the successor block. */
3691 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
3693 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3695 "Unsplit EH landing pad %d to block %i "
3696 "(via cleanup_empty_eh).\n",
3697 lp
->index
, e_out
->dest
->index
);
3704 /* Examine the block associated with LP to determine if it's an empty
3705 handler for its EH region. If so, attempt to redirect EH edges to
3706 an outer region. Return true the CFG was updated in any way. This
3707 is similar to jump forwarding, just across EH edges. */
3710 cleanup_empty_eh (eh_landing_pad lp
)
3712 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3713 gimple_stmt_iterator gsi
;
3715 eh_region new_region
;
3718 bool has_non_eh_pred
;
3721 /* There can be zero or one edges out of BB. This is the quickest test. */
3722 switch (EDGE_COUNT (bb
->succs
))
3728 e_out
= EDGE_SUCC (bb
, 0);
3733 gsi
= gsi_after_labels (bb
);
3735 /* Make sure to skip debug statements. */
3736 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3737 gsi_next_nondebug (&gsi
);
3739 /* If the block is totally empty, look for more unsplitting cases. */
3740 if (gsi_end_p (gsi
))
3741 return cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
3743 /* The block should consist only of a single RESX statement. */
3744 resx
= gsi_stmt (gsi
);
3745 if (!is_gimple_resx (resx
))
3747 gcc_assert (gsi_one_before_end_p (gsi
));
3749 /* Determine if there are non-EH edges, or resx edges into the handler. */
3750 has_non_eh_pred
= false;
3751 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3752 if (!(e
->flags
& EDGE_EH
))
3753 has_non_eh_pred
= true;
3755 /* Find the handler that's outer of the empty handler by looking at
3756 where the RESX instruction was vectored. */
3757 new_lp_nr
= lookup_stmt_eh_lp (resx
);
3758 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
3760 /* If there's no destination region within the current function,
3761 redirection is trivial via removing the throwing statements from
3762 the EH region, removing the EH edges, and allowing the block
3763 to go unreachable. */
3764 if (new_region
== NULL
)
3766 gcc_assert (e_out
== NULL
);
3767 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3768 if (e
->flags
& EDGE_EH
)
3770 gimple stmt
= last_stmt (e
->src
);
3771 remove_stmt_from_eh_lp (stmt
);
3779 /* If the destination region is a MUST_NOT_THROW, allow the runtime
3780 to handle the abort and allow the blocks to go unreachable. */
3781 if (new_region
->type
== ERT_MUST_NOT_THROW
)
3783 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3784 if (e
->flags
& EDGE_EH
)
3786 gimple stmt
= last_stmt (e
->src
);
3787 remove_stmt_from_eh_lp (stmt
);
3788 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
3796 /* Try to redirect the EH edges and merge the PHIs into the destination
3797 landing pad block. If the merge succeeds, we'll already have redirected
3798 all the EH edges. The handler itself will go unreachable if there were
3800 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
3803 /* Finally, if all input edges are EH edges, then we can (potentially)
3804 reduce the number of transfers from the runtime by moving the landing
3805 pad from the original region to the new region. This is a win when
3806 we remove the last CLEANUP region along a particular exception
3807 propagation path. Since nothing changes except for the region with
3808 which the landing pad is associated, the PHI nodes do not need to be
3810 if (!has_non_eh_pred
)
3812 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
3813 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3814 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
3815 lp
->index
, new_region
->index
);
3817 /* ??? The CFG didn't change, but we may have rendered the
3818 old EH region unreachable. Trigger a cleanup there. */
3825 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3826 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
3827 remove_eh_landing_pad (lp
);
3831 /* Do a post-order traversal of the EH region tree. Examine each
3832 post_landing_pad block and see if we can eliminate it as empty. */
3835 cleanup_all_empty_eh (void)
3837 bool changed
= false;
3841 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3843 changed
|= cleanup_empty_eh (lp
);
3848 /* Perform cleanups and lowering of exception handling
3849 1) cleanups regions with handlers doing nothing are optimized out
3850 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
3851 3) Info about regions that are containing instructions, and regions
3852 reachable via local EH edges is collected
3853 4) Eh tree is pruned for regions no longer neccesary.
3855 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
3856 Unify those that have the same failure decl and locus.
3860 execute_cleanup_eh (void)
3862 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
3863 looking up unreachable landing pads. */
3864 remove_unreachable_handlers ();
3866 /* Watch out for the region tree vanishing due to all unreachable. */
3867 if (cfun
->eh
->region_tree
&& optimize
)
3869 bool changed
= false;
3871 changed
|= unsplit_all_eh ();
3872 changed
|= cleanup_all_empty_eh ();
3876 free_dominance_info (CDI_DOMINATORS
);
3877 free_dominance_info (CDI_POST_DOMINATORS
);
3879 /* We delayed all basic block deletion, as we may have performed
3880 cleanups on EH edges while non-EH edges were still present. */
3881 delete_unreachable_blocks ();
3883 /* We manipulated the landing pads. Remove any region that no
3884 longer has a landing pad. */
3885 remove_unreachable_handlers_no_lp ();
3887 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
3895 gate_cleanup_eh (void)
3897 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
3900 struct gimple_opt_pass pass_cleanup_eh
= {
3903 "ehcleanup", /* name */
3904 gate_cleanup_eh
, /* gate */
3905 execute_cleanup_eh
, /* execute */
3908 0, /* static_pass_number */
3909 TV_TREE_EH
, /* tv_id */
3910 PROP_gimple_lcf
, /* properties_required */
3911 0, /* properties_provided */
3912 0, /* properties_destroyed */
3913 0, /* todo_flags_start */
3914 TODO_dump_func
/* todo_flags_finish */
3918 /* Verify that BB containing STMT as the last statement, has precisely the
3919 edge that make_eh_edges would create. */
3922 verify_eh_edges (gimple stmt
)
3924 basic_block bb
= gimple_bb (stmt
);
3925 eh_landing_pad lp
= NULL
;
3930 lp_nr
= lookup_stmt_eh_lp (stmt
);
3932 lp
= get_eh_landing_pad_from_number (lp_nr
);
3935 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3937 if (e
->flags
& EDGE_EH
)
3941 error ("BB %i has multiple EH edges", bb
->index
);
3953 error ("BB %i can not throw but has an EH edge", bb
->index
);
3959 if (!stmt_could_throw_p (stmt
))
3961 error ("BB %i last statement has incorrectly set lp", bb
->index
);
3965 if (eh_edge
== NULL
)
3967 error ("BB %i is missing an EH edge", bb
->index
);
3971 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
3973 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
3980 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
3983 verify_eh_dispatch_edge (gimple stmt
)
3987 basic_block src
, dst
;
3988 bool want_fallthru
= true;
3992 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
3993 src
= gimple_bb (stmt
);
3995 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3996 gcc_assert (e
->aux
== NULL
);
4001 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4003 dst
= label_to_block (c
->label
);
4004 e
= find_edge (src
, dst
);
4007 error ("BB %i is missing an edge", src
->index
);
4012 /* A catch-all handler doesn't have a fallthru. */
4013 if (c
->type_list
== NULL
)
4015 want_fallthru
= false;
4021 case ERT_ALLOWED_EXCEPTIONS
:
4022 dst
= label_to_block (r
->u
.allowed
.label
);
4023 e
= find_edge (src
, dst
);
4026 error ("BB %i is missing an edge", src
->index
);
4037 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4039 if (e
->flags
& EDGE_FALLTHRU
)
4041 if (fall_edge
!= NULL
)
4043 error ("BB %i too many fallthru edges", src
->index
);
4052 error ("BB %i has incorrect edge", src
->index
);
4056 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4058 error ("BB %i has incorrect fallthru edge", src
->index
);