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_alloc_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 the eh_protect_cleanup_actions
955 langhook returns non-null, then the language requires that the exception
956 path out of a try_finally be treated specially. To wit: the code within
957 the finally block may not itself throw an exception. We have two choices
958 here. First we can duplicate the finally block and wrap it in a
959 must_not_throw 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_hooks
.eh_protect_cleanup_actions
== NULL
)
988 protect_cleanup_actions
= lang_hooks
.eh_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 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2445 case MISALIGNED_INDIRECT_REF
:
2446 return !TREE_THIS_NOTRAP (expr
);
2449 return TREE_THIS_VOLATILE (expr
);
2452 t
= get_callee_fndecl (expr
);
2453 /* Assume that calls to weak functions may trap. */
2454 if (!t
|| !DECL_P (t
) || DECL_WEAK (t
))
2464 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2465 an assignment or a conditional) may throw. */
2468 stmt_could_throw_1_p (gimple stmt
)
2470 enum tree_code code
= gimple_expr_code (stmt
);
2471 bool honor_nans
= false;
2472 bool honor_snans
= false;
2473 bool fp_operation
= false;
2474 bool honor_trapv
= false;
2479 if (TREE_CODE_CLASS (code
) == tcc_comparison
2480 || TREE_CODE_CLASS (code
) == tcc_unary
2481 || TREE_CODE_CLASS (code
) == tcc_binary
)
2483 t
= gimple_expr_type (stmt
);
2484 fp_operation
= FLOAT_TYPE_P (t
);
2487 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2488 honor_snans
= flag_signaling_nans
!= 0;
2490 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2494 /* Check if the main expression may trap. */
2495 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2496 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2497 honor_nans
, honor_snans
, t
,
2502 /* If the expression does not trap, see if any of the individual operands may
2504 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2505 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2512 /* Return true if statement STMT could throw an exception. */
2515 stmt_could_throw_p (gimple stmt
)
2517 if (!flag_exceptions
)
2520 /* The only statements that can throw an exception are assignments,
2521 conditionals, calls, resx, and asms. */
2522 switch (gimple_code (stmt
))
2528 return !gimple_call_nothrow_p (stmt
);
2532 if (!cfun
->can_throw_non_call_exceptions
)
2534 return stmt_could_throw_1_p (stmt
);
2537 if (!cfun
->can_throw_non_call_exceptions
)
2539 return gimple_asm_volatile_p (stmt
);
2547 /* Return true if expression T could throw an exception. */
2550 tree_could_throw_p (tree t
)
2552 if (!flag_exceptions
)
2554 if (TREE_CODE (t
) == MODIFY_EXPR
)
2556 if (cfun
->can_throw_non_call_exceptions
2557 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2559 t
= TREE_OPERAND (t
, 1);
2562 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2563 t
= TREE_OPERAND (t
, 0);
2564 if (TREE_CODE (t
) == CALL_EXPR
)
2565 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2566 if (cfun
->can_throw_non_call_exceptions
)
2567 return tree_could_trap_p (t
);
2571 /* Return true if STMT can throw an exception that is not caught within
2572 the current function (CFUN). */
2575 stmt_can_throw_external (gimple stmt
)
2579 if (!stmt_could_throw_p (stmt
))
2582 lp_nr
= lookup_stmt_eh_lp (stmt
);
2586 /* Return true if STMT can throw an exception that is caught within
2587 the current function (CFUN). */
2590 stmt_can_throw_internal (gimple stmt
)
2594 if (!stmt_could_throw_p (stmt
))
2597 lp_nr
= lookup_stmt_eh_lp (stmt
);
2601 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2602 remove any entry it might have from the EH table. Return true if
2603 any change was made. */
2606 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2608 if (stmt_could_throw_p (stmt
))
2610 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2613 /* Likewise, but always use the current function. */
2616 maybe_clean_eh_stmt (gimple stmt
)
2618 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2621 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2622 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2623 in the table if it should be in there. Return TRUE if a replacement was
2624 done that my require an EH edge purge. */
2627 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2629 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2633 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2635 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2638 remove_stmt_from_eh_lp (old_stmt
);
2639 if (new_stmt_could_throw
)
2641 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2651 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2652 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2653 operand is the return value of duplicate_eh_regions. */
2656 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2657 struct function
*old_fun
, gimple old_stmt
,
2658 struct pointer_map_t
*map
, int default_lp_nr
)
2660 int old_lp_nr
, new_lp_nr
;
2663 if (!stmt_could_throw_p (new_stmt
))
2666 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2669 if (default_lp_nr
== 0)
2671 new_lp_nr
= default_lp_nr
;
2673 else if (old_lp_nr
> 0)
2675 eh_landing_pad old_lp
, new_lp
;
2677 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2678 slot
= pointer_map_contains (map
, old_lp
);
2679 new_lp
= (eh_landing_pad
) *slot
;
2680 new_lp_nr
= new_lp
->index
;
2684 eh_region old_r
, new_r
;
2686 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2687 slot
= pointer_map_contains (map
, old_r
);
2688 new_r
= (eh_region
) *slot
;
2689 new_lp_nr
= -new_r
->index
;
2692 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2696 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2697 and thus no remapping is required. */
2700 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2704 if (!stmt_could_throw_p (new_stmt
))
2707 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2711 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2715 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2716 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2717 this only handles handlers consisting of a single call, as that's the
2718 important case for C++: a destructor call for a particular object showing
2719 up in multiple handlers. */
2722 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2724 gimple_stmt_iterator gsi
;
2728 gsi
= gsi_start (oneh
);
2729 if (!gsi_one_before_end_p (gsi
))
2731 ones
= gsi_stmt (gsi
);
2733 gsi
= gsi_start (twoh
);
2734 if (!gsi_one_before_end_p (gsi
))
2736 twos
= gsi_stmt (gsi
);
2738 if (!is_gimple_call (ones
)
2739 || !is_gimple_call (twos
)
2740 || gimple_call_lhs (ones
)
2741 || gimple_call_lhs (twos
)
2742 || gimple_call_chain (ones
)
2743 || gimple_call_chain (twos
)
2744 || !operand_equal_p (gimple_call_fn (ones
), gimple_call_fn (twos
), 0)
2745 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2748 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2749 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2750 gimple_call_arg (twos
, ai
), 0))
2757 try { A() } finally { try { ~B() } catch { ~A() } }
2758 try { ... } finally { ~A() }
2760 try { A() } catch { ~B() }
2761 try { ~B() ... } finally { ~A() }
2763 This occurs frequently in C++, where A is a local variable and B is a
2764 temporary used in the initializer for A. */
2767 optimize_double_finally (gimple one
, gimple two
)
2770 gimple_stmt_iterator gsi
;
2772 gsi
= gsi_start (gimple_try_cleanup (one
));
2773 if (!gsi_one_before_end_p (gsi
))
2776 oneh
= gsi_stmt (gsi
);
2777 if (gimple_code (oneh
) != GIMPLE_TRY
2778 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2781 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2783 gimple_seq seq
= gimple_try_eval (oneh
);
2785 gimple_try_set_cleanup (one
, seq
);
2786 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2787 seq
= copy_gimple_seq_and_replace_locals (seq
);
2788 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2789 gimple_try_set_eval (two
, seq
);
2793 /* Perform EH refactoring optimizations that are simpler to do when code
2794 flow has been lowered but EH structures haven't. */
2797 refactor_eh_r (gimple_seq seq
)
2799 gimple_stmt_iterator gsi
;
2804 gsi
= gsi_start (seq
);
2808 if (gsi_end_p (gsi
))
2811 two
= gsi_stmt (gsi
);
2814 && gimple_code (one
) == GIMPLE_TRY
2815 && gimple_code (two
) == GIMPLE_TRY
2816 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2817 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2818 optimize_double_finally (one
, two
);
2820 switch (gimple_code (one
))
2823 refactor_eh_r (gimple_try_eval (one
));
2824 refactor_eh_r (gimple_try_cleanup (one
));
2827 refactor_eh_r (gimple_catch_handler (one
));
2829 case GIMPLE_EH_FILTER
:
2830 refactor_eh_r (gimple_eh_filter_failure (one
));
2845 refactor_eh_r (gimple_body (current_function_decl
));
2850 gate_refactor_eh (void)
2852 return flag_exceptions
!= 0;
2855 struct gimple_opt_pass pass_refactor_eh
=
2860 gate_refactor_eh
, /* gate */
2861 refactor_eh
, /* execute */
2864 0, /* static_pass_number */
2865 TV_TREE_EH
, /* tv_id */
2866 PROP_gimple_lcf
, /* properties_required */
2867 0, /* properties_provided */
2868 0, /* properties_destroyed */
2869 0, /* todo_flags_start */
2870 TODO_dump_func
/* todo_flags_finish */
2874 /* At the end of gimple optimization, we can lower RESX. */
2877 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2880 eh_region src_r
, dst_r
;
2881 gimple_stmt_iterator gsi
;
2886 lp_nr
= lookup_stmt_eh_lp (stmt
);
2888 dst_r
= get_eh_region_from_lp_number (lp_nr
);
2892 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
2893 gsi
= gsi_last_bb (bb
);
2897 /* We can wind up with no source region when pass_cleanup_eh shows
2898 that there are no entries into an eh region and deletes it, but
2899 then the block that contains the resx isn't removed. This can
2900 happen without optimization when the switch statement created by
2901 lower_try_finally_switch isn't simplified to remove the eh case.
2903 Resolve this by expanding the resx node to an abort. */
2905 fn
= implicit_built_in_decls
[BUILT_IN_TRAP
];
2906 x
= gimple_build_call (fn
, 0);
2907 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2909 while (EDGE_COUNT (bb
->succs
) > 0)
2910 remove_edge (EDGE_SUCC (bb
, 0));
2914 /* When we have a destination region, we resolve this by copying
2915 the excptr and filter values into place, and changing the edge
2916 to immediately after the landing pad. */
2925 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
2926 the failure decl into a new block, if needed. */
2927 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
2929 slot
= pointer_map_contains (mnt_map
, dst_r
);
2932 gimple_stmt_iterator gsi2
;
2934 new_bb
= create_empty_bb (bb
);
2935 lab
= gimple_block_label (new_bb
);
2936 gsi2
= gsi_start_bb (new_bb
);
2938 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
2939 x
= gimple_build_call (fn
, 0);
2940 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
2941 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
2943 slot
= pointer_map_insert (mnt_map
, dst_r
);
2949 new_bb
= label_to_block (lab
);
2952 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
2953 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
2954 e
->count
= bb
->count
;
2955 e
->probability
= REG_BR_PROB_BASE
;
2960 tree dst_nr
= build_int_cst (NULL
, dst_r
->index
);
2962 fn
= implicit_built_in_decls
[BUILT_IN_EH_COPY_VALUES
];
2963 src_nr
= build_int_cst (NULL
, src_r
->index
);
2964 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
2965 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2967 /* Update the flags for the outgoing edge. */
2968 e
= single_succ_edge (bb
);
2969 gcc_assert (e
->flags
& EDGE_EH
);
2970 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
2972 /* If there are no more EH users of the landing pad, delete it. */
2973 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
2974 if (e
->flags
& EDGE_EH
)
2978 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
2979 remove_eh_landing_pad (lp
);
2989 /* When we don't have a destination region, this exception escapes
2990 up the call chain. We resolve this by generating a call to the
2991 _Unwind_Resume library function. */
2993 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
2994 with no arguments for C++ and Java. Check for that. */
2995 if (src_r
->use_cxa_end_cleanup
)
2997 fn
= implicit_built_in_decls
[BUILT_IN_CXA_END_CLEANUP
];
2998 x
= gimple_build_call (fn
, 0);
2999 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3003 fn
= implicit_built_in_decls
[BUILT_IN_EH_POINTER
];
3004 src_nr
= build_int_cst (NULL
, src_r
->index
);
3005 x
= gimple_build_call (fn
, 1, src_nr
);
3006 var
= create_tmp_var (ptr_type_node
, NULL
);
3007 var
= make_ssa_name (var
, x
);
3008 gimple_call_set_lhs (x
, var
);
3009 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3011 fn
= implicit_built_in_decls
[BUILT_IN_UNWIND_RESUME
];
3012 x
= gimple_build_call (fn
, 1, var
);
3013 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3016 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3019 gsi_remove (&gsi
, true);
3025 execute_lower_resx (void)
3028 struct pointer_map_t
*mnt_map
;
3029 bool dominance_invalidated
= false;
3030 bool any_rewritten
= false;
3032 mnt_map
= pointer_map_create ();
3036 gimple last
= last_stmt (bb
);
3037 if (last
&& is_gimple_resx (last
))
3039 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
3040 any_rewritten
= true;
3044 pointer_map_destroy (mnt_map
);
3046 if (dominance_invalidated
)
3048 free_dominance_info (CDI_DOMINATORS
);
3049 free_dominance_info (CDI_POST_DOMINATORS
);
3052 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3056 gate_lower_resx (void)
3058 return flag_exceptions
!= 0;
3061 struct gimple_opt_pass pass_lower_resx
=
3066 gate_lower_resx
, /* gate */
3067 execute_lower_resx
, /* execute */
3070 0, /* static_pass_number */
3071 TV_TREE_EH
, /* tv_id */
3072 PROP_gimple_lcf
, /* properties_required */
3073 0, /* properties_provided */
3074 0, /* properties_destroyed */
3075 0, /* todo_flags_start */
3076 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3081 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3082 we have found some duplicate labels and removed some edges. */
3085 lower_eh_dispatch (basic_block src
, gimple stmt
)
3087 gimple_stmt_iterator gsi
;
3092 bool redirected
= false;
3094 region_nr
= gimple_eh_dispatch_region (stmt
);
3095 r
= get_eh_region_from_number (region_nr
);
3097 gsi
= gsi_last_bb (src
);
3103 VEC (tree
, heap
) *labels
= NULL
;
3104 tree default_label
= NULL
;
3108 struct pointer_set_t
*seen_values
= pointer_set_create ();
3110 /* Collect the labels for a switch. Zero the post_landing_pad
3111 field becase we'll no longer have anything keeping these labels
3112 in existance and the optimizer will be free to merge these
3114 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3116 tree tp_node
, flt_node
, lab
= c
->label
;
3117 bool have_label
= false;
3120 tp_node
= c
->type_list
;
3121 flt_node
= c
->filter_list
;
3123 if (tp_node
== NULL
)
3125 default_label
= lab
;
3130 /* Filter out duplicate labels that arise when this handler
3131 is shadowed by an earlier one. When no labels are
3132 attached to the handler anymore, we remove
3133 the corresponding edge and then we delete unreachable
3134 blocks at the end of this pass. */
3135 if (! pointer_set_contains (seen_values
, TREE_VALUE (flt_node
)))
3137 tree t
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3138 TREE_VALUE (flt_node
), NULL
, lab
);
3139 VEC_safe_push (tree
, heap
, labels
, t
);
3140 pointer_set_insert (seen_values
, TREE_VALUE (flt_node
));
3144 tp_node
= TREE_CHAIN (tp_node
);
3145 flt_node
= TREE_CHAIN (flt_node
);
3150 remove_edge (find_edge (src
, label_to_block (lab
)));
3155 /* Clean up the edge flags. */
3156 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3158 if (e
->flags
& EDGE_FALLTHRU
)
3160 /* If there was no catch-all, use the fallthru edge. */
3161 if (default_label
== NULL
)
3162 default_label
= gimple_block_label (e
->dest
);
3163 e
->flags
&= ~EDGE_FALLTHRU
;
3166 gcc_assert (default_label
!= NULL
);
3168 /* Don't generate a switch if there's only a default case.
3169 This is common in the form of try { A; } catch (...) { B; }. */
3172 e
= single_succ_edge (src
);
3173 e
->flags
|= EDGE_FALLTHRU
;
3177 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3178 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3179 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3180 filter
= make_ssa_name (filter
, x
);
3181 gimple_call_set_lhs (x
, filter
);
3182 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3184 /* Turn the default label into a default case. */
3185 default_label
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3186 NULL
, NULL
, default_label
);
3187 sort_case_labels (labels
);
3189 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3190 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3192 VEC_free (tree
, heap
, labels
);
3194 pointer_set_destroy (seen_values
);
3198 case ERT_ALLOWED_EXCEPTIONS
:
3200 edge b_e
= BRANCH_EDGE (src
);
3201 edge f_e
= FALLTHRU_EDGE (src
);
3203 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3204 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3205 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3206 filter
= make_ssa_name (filter
, x
);
3207 gimple_call_set_lhs (x
, filter
);
3208 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3210 r
->u
.allowed
.label
= NULL
;
3211 x
= gimple_build_cond (EQ_EXPR
, filter
,
3212 build_int_cst (TREE_TYPE (filter
),
3213 r
->u
.allowed
.filter
),
3214 NULL_TREE
, NULL_TREE
);
3215 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3217 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3218 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3226 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3227 gsi_remove (&gsi
, true);
3232 execute_lower_eh_dispatch (void)
3235 bool any_rewritten
= false;
3236 bool redirected
= false;
3238 assign_filter_values ();
3242 gimple last
= last_stmt (bb
);
3243 if (last
&& gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3245 redirected
|= lower_eh_dispatch (bb
, last
);
3246 any_rewritten
= true;
3251 delete_unreachable_blocks ();
3252 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3256 gate_lower_eh_dispatch (void)
3258 return cfun
->eh
->region_tree
!= NULL
;
3261 struct gimple_opt_pass pass_lower_eh_dispatch
=
3265 "ehdisp", /* name */
3266 gate_lower_eh_dispatch
, /* gate */
3267 execute_lower_eh_dispatch
, /* execute */
3270 0, /* static_pass_number */
3271 TV_TREE_EH
, /* tv_id */
3272 PROP_gimple_lcf
, /* properties_required */
3273 0, /* properties_provided */
3274 0, /* properties_destroyed */
3275 0, /* todo_flags_start */
3276 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3280 /* Walk statements, see what regions are really referenced and remove
3281 those that are unused. */
3284 remove_unreachable_handlers (void)
3286 sbitmap r_reachable
, lp_reachable
;
3292 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3294 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3295 sbitmap_zero (r_reachable
);
3296 sbitmap_zero (lp_reachable
);
3300 gimple_stmt_iterator gsi
= gsi_start_bb (bb
);
3302 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3304 gimple stmt
= gsi_stmt (gsi
);
3305 lp_nr
= lookup_stmt_eh_lp (stmt
);
3307 /* Negative LP numbers are MUST_NOT_THROW regions which
3308 are not considered BB enders. */
3310 SET_BIT (r_reachable
, -lp_nr
);
3312 /* Positive LP numbers are real landing pads, are are BB enders. */
3315 gcc_assert (gsi_one_before_end_p (gsi
));
3316 region
= get_eh_region_from_lp_number (lp_nr
);
3317 SET_BIT (r_reachable
, region
->index
);
3318 SET_BIT (lp_reachable
, lp_nr
);
3325 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3326 dump_eh_tree (dump_file
, cfun
);
3327 fprintf (dump_file
, "Reachable regions: ");
3328 dump_sbitmap_file (dump_file
, r_reachable
);
3329 fprintf (dump_file
, "Reachable landing pads: ");
3330 dump_sbitmap_file (dump_file
, lp_reachable
);
3334 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3335 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3338 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3339 remove_eh_handler (region
);
3343 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3344 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3347 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3348 remove_eh_landing_pad (lp
);
3353 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3354 dump_eh_tree (dump_file
, cfun
);
3355 fprintf (dump_file
, "\n\n");
3358 sbitmap_free (r_reachable
);
3359 sbitmap_free (lp_reachable
);
3361 #ifdef ENABLE_CHECKING
3362 verify_eh_tree (cfun
);
3366 /* Remove regions that do not have landing pads. This assumes
3367 that remove_unreachable_handlers has already been run, and
3368 that we've just manipulated the landing pads since then. */
3371 remove_unreachable_handlers_no_lp (void)
3376 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3377 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
)
3380 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3381 remove_eh_handler (r
);
3385 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3386 optimisticaly split all sorts of edges, including EH edges. The
3387 optimization passes in between may not have needed them; if not,
3388 we should undo the split.
3390 Recognize this case by having one EH edge incoming to the BB and
3391 one normal edge outgoing; BB should be empty apart from the
3392 post_landing_pad label.
3394 Note that this is slightly different from the empty handler case
3395 handled by cleanup_empty_eh, in that the actual handler may yet
3396 have actual code but the landing pad has been separated from the
3397 handler. As such, cleanup_empty_eh relies on this transformation
3398 having been done first. */
3401 unsplit_eh (eh_landing_pad lp
)
3403 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3404 gimple_stmt_iterator gsi
;
3407 /* Quickly check the edge counts on BB for singularity. */
3408 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3410 e_in
= EDGE_PRED (bb
, 0);
3411 e_out
= EDGE_SUCC (bb
, 0);
3413 /* Input edge must be EH and output edge must be normal. */
3414 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3417 /* The block must be empty except for the labels and debug insns. */
3418 gsi
= gsi_after_labels (bb
);
3419 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3420 gsi_next_nondebug (&gsi
);
3421 if (!gsi_end_p (gsi
))
3424 /* The destination block must not already have a landing pad
3425 for a different region. */
3426 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3428 gimple stmt
= gsi_stmt (gsi
);
3432 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3434 lab
= gimple_label_label (stmt
);
3435 lp_nr
= EH_LANDING_PAD_NR (lab
);
3436 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3440 /* The new destination block must not already be a destination of
3441 the source block, lest we merge fallthru and eh edges and get
3442 all sorts of confused. */
3443 if (find_edge (e_in
->src
, e_out
->dest
))
3446 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3447 thought this should have been cleaned up by a phicprop pass, but
3448 that doesn't appear to handle virtuals. Propagate by hand. */
3449 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3451 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3453 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3454 tree lhs
= gimple_phi_result (phi
);
3455 tree rhs
= gimple_phi_arg_def (phi
, 0);
3456 use_operand_p use_p
;
3457 imm_use_iterator iter
;
3459 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3461 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3462 SET_USE (use_p
, rhs
);
3465 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3466 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3468 remove_phi_node (&gsi
, true);
3472 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3473 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3474 lp
->index
, e_out
->dest
->index
);
3476 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3477 a successor edge, humor it. But do the real CFG change with the
3478 predecessor of E_OUT in order to preserve the ordering of arguments
3479 to the PHI nodes in E_OUT->DEST. */
3480 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3481 redirect_edge_pred (e_out
, e_in
->src
);
3482 e_out
->flags
= e_in
->flags
;
3483 e_out
->probability
= e_in
->probability
;
3484 e_out
->count
= e_in
->count
;
3490 /* Examine each landing pad block and see if it matches unsplit_eh. */
3493 unsplit_all_eh (void)
3495 bool changed
= false;
3499 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3501 changed
|= unsplit_eh (lp
);
3506 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3507 to OLD_BB to NEW_BB; return true on success, false on failure.
3509 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3510 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3511 Virtual PHIs may be deleted and marked for renaming. */
3514 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3515 edge old_bb_out
, bool change_region
)
3517 gimple_stmt_iterator ngsi
, ogsi
;
3520 bitmap rename_virts
;
3521 bitmap ophi_handled
;
3523 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3524 redirect_edge_var_map_clear (e
);
3526 ophi_handled
= BITMAP_ALLOC (NULL
);
3527 rename_virts
= BITMAP_ALLOC (NULL
);
3529 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3530 for the edges we're going to move. */
3531 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3533 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3536 nresult
= gimple_phi_result (nphi
);
3537 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3539 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3540 the source ssa_name. */
3542 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3544 ophi
= gsi_stmt (ogsi
);
3545 if (gimple_phi_result (ophi
) == nop
)
3550 /* If we did find the corresponding PHI, copy those inputs. */
3553 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3554 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3559 if ((e
->flags
& EDGE_EH
) == 0)
3561 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3562 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3563 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3566 /* If we didn't find the PHI, but it's a VOP, remember to rename
3567 it later, assuming all other tests succeed. */
3568 else if (!is_gimple_reg (nresult
))
3569 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3570 /* If we didn't find the PHI, and it's a real variable, we know
3571 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3572 variable is unchanged from input to the block and we can simply
3573 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3577 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3578 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3579 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3583 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3584 we don't know what values from the other edges into NEW_BB to use. */
3585 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3587 gimple ophi
= gsi_stmt (ogsi
);
3588 tree oresult
= gimple_phi_result (ophi
);
3589 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3593 /* At this point we know that the merge will succeed. Remove the PHI
3594 nodes for the virtuals that we want to rename. */
3595 if (!bitmap_empty_p (rename_virts
))
3597 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3599 gimple nphi
= gsi_stmt (ngsi
);
3600 tree nresult
= gimple_phi_result (nphi
);
3601 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3603 mark_virtual_phi_result_for_renaming (nphi
);
3604 remove_phi_node (&ngsi
, true);
3611 /* Finally, move the edges and update the PHIs. */
3612 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3613 if (e
->flags
& EDGE_EH
)
3615 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3616 redirect_edge_succ (e
, new_bb
);
3617 flush_pending_stmts (e
);
3622 BITMAP_FREE (ophi_handled
);
3623 BITMAP_FREE (rename_virts
);
3627 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3628 redirect_edge_var_map_clear (e
);
3629 BITMAP_FREE (ophi_handled
);
3630 BITMAP_FREE (rename_virts
);
3634 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3635 old region to NEW_REGION at BB. */
3638 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3639 eh_landing_pad lp
, eh_region new_region
)
3641 gimple_stmt_iterator gsi
;
3644 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3648 lp
->region
= new_region
;
3649 lp
->next_lp
= new_region
->landing_pads
;
3650 new_region
->landing_pads
= lp
;
3652 /* Delete the RESX that was matched within the empty handler block. */
3653 gsi
= gsi_last_bb (bb
);
3654 mark_virtual_ops_for_renaming (gsi_stmt (gsi
));
3655 gsi_remove (&gsi
, true);
3657 /* Clean up E_OUT for the fallthru. */
3658 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3659 e_out
->probability
= REG_BR_PROB_BASE
;
3662 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3663 unsplitting than unsplit_eh was prepared to handle, e.g. when
3664 multiple incoming edges and phis are involved. */
3667 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3669 gimple_stmt_iterator gsi
;
3672 /* We really ought not have totally lost everything following
3673 a landing pad label. Given that BB is empty, there had better
3675 gcc_assert (e_out
!= NULL
);
3677 /* The destination block must not already have a landing pad
3678 for a different region. */
3680 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3682 gimple stmt
= gsi_stmt (gsi
);
3685 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3687 lab
= gimple_label_label (stmt
);
3688 lp_nr
= EH_LANDING_PAD_NR (lab
);
3689 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3693 /* Attempt to move the PHIs into the successor block. */
3694 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
3696 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3698 "Unsplit EH landing pad %d to block %i "
3699 "(via cleanup_empty_eh).\n",
3700 lp
->index
, e_out
->dest
->index
);
3707 /* Examine the block associated with LP to determine if it's an empty
3708 handler for its EH region. If so, attempt to redirect EH edges to
3709 an outer region. Return true the CFG was updated in any way. This
3710 is similar to jump forwarding, just across EH edges. */
3713 cleanup_empty_eh (eh_landing_pad lp
)
3715 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3716 gimple_stmt_iterator gsi
;
3718 eh_region new_region
;
3721 bool has_non_eh_pred
;
3724 /* There can be zero or one edges out of BB. This is the quickest test. */
3725 switch (EDGE_COUNT (bb
->succs
))
3731 e_out
= EDGE_SUCC (bb
, 0);
3736 gsi
= gsi_after_labels (bb
);
3738 /* Make sure to skip debug statements. */
3739 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3740 gsi_next_nondebug (&gsi
);
3742 /* If the block is totally empty, look for more unsplitting cases. */
3743 if (gsi_end_p (gsi
))
3744 return cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
3746 /* The block should consist only of a single RESX statement. */
3747 resx
= gsi_stmt (gsi
);
3748 if (!is_gimple_resx (resx
))
3750 gcc_assert (gsi_one_before_end_p (gsi
));
3752 /* Determine if there are non-EH edges, or resx edges into the handler. */
3753 has_non_eh_pred
= false;
3754 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3755 if (!(e
->flags
& EDGE_EH
))
3756 has_non_eh_pred
= true;
3758 /* Find the handler that's outer of the empty handler by looking at
3759 where the RESX instruction was vectored. */
3760 new_lp_nr
= lookup_stmt_eh_lp (resx
);
3761 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
3763 /* If there's no destination region within the current function,
3764 redirection is trivial via removing the throwing statements from
3765 the EH region, removing the EH edges, and allowing the block
3766 to go unreachable. */
3767 if (new_region
== NULL
)
3769 gcc_assert (e_out
== NULL
);
3770 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3771 if (e
->flags
& EDGE_EH
)
3773 gimple stmt
= last_stmt (e
->src
);
3774 remove_stmt_from_eh_lp (stmt
);
3782 /* If the destination region is a MUST_NOT_THROW, allow the runtime
3783 to handle the abort and allow the blocks to go unreachable. */
3784 if (new_region
->type
== ERT_MUST_NOT_THROW
)
3786 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3787 if (e
->flags
& EDGE_EH
)
3789 gimple stmt
= last_stmt (e
->src
);
3790 remove_stmt_from_eh_lp (stmt
);
3791 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
3799 /* Try to redirect the EH edges and merge the PHIs into the destination
3800 landing pad block. If the merge succeeds, we'll already have redirected
3801 all the EH edges. The handler itself will go unreachable if there were
3803 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
3806 /* Finally, if all input edges are EH edges, then we can (potentially)
3807 reduce the number of transfers from the runtime by moving the landing
3808 pad from the original region to the new region. This is a win when
3809 we remove the last CLEANUP region along a particular exception
3810 propagation path. Since nothing changes except for the region with
3811 which the landing pad is associated, the PHI nodes do not need to be
3813 if (!has_non_eh_pred
)
3815 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
3816 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3817 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
3818 lp
->index
, new_region
->index
);
3820 /* ??? The CFG didn't change, but we may have rendered the
3821 old EH region unreachable. Trigger a cleanup there. */
3828 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3829 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
3830 remove_eh_landing_pad (lp
);
3834 /* Do a post-order traversal of the EH region tree. Examine each
3835 post_landing_pad block and see if we can eliminate it as empty. */
3838 cleanup_all_empty_eh (void)
3840 bool changed
= false;
3844 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3846 changed
|= cleanup_empty_eh (lp
);
3851 /* Perform cleanups and lowering of exception handling
3852 1) cleanups regions with handlers doing nothing are optimized out
3853 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
3854 3) Info about regions that are containing instructions, and regions
3855 reachable via local EH edges is collected
3856 4) Eh tree is pruned for regions no longer neccesary.
3858 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
3859 Unify those that have the same failure decl and locus.
3863 execute_cleanup_eh_1 (void)
3865 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
3866 looking up unreachable landing pads. */
3867 remove_unreachable_handlers ();
3869 /* Watch out for the region tree vanishing due to all unreachable. */
3870 if (cfun
->eh
->region_tree
&& optimize
)
3872 bool changed
= false;
3874 changed
|= unsplit_all_eh ();
3875 changed
|= cleanup_all_empty_eh ();
3879 free_dominance_info (CDI_DOMINATORS
);
3880 free_dominance_info (CDI_POST_DOMINATORS
);
3882 /* We delayed all basic block deletion, as we may have performed
3883 cleanups on EH edges while non-EH edges were still present. */
3884 delete_unreachable_blocks ();
3886 /* We manipulated the landing pads. Remove any region that no
3887 longer has a landing pad. */
3888 remove_unreachable_handlers_no_lp ();
3890 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
3898 execute_cleanup_eh (void)
3900 int ret
= execute_cleanup_eh_1 ();
3902 /* If the function no longer needs an EH personality routine
3903 clear it. This exposes cross-language inlining opportunities
3904 and avoids references to a never defined personality routine. */
3905 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
3906 && function_needs_eh_personality (cfun
) != eh_personality_lang
)
3907 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
3913 gate_cleanup_eh (void)
3915 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
3918 struct gimple_opt_pass pass_cleanup_eh
= {
3921 "ehcleanup", /* name */
3922 gate_cleanup_eh
, /* gate */
3923 execute_cleanup_eh
, /* execute */
3926 0, /* static_pass_number */
3927 TV_TREE_EH
, /* tv_id */
3928 PROP_gimple_lcf
, /* properties_required */
3929 0, /* properties_provided */
3930 0, /* properties_destroyed */
3931 0, /* todo_flags_start */
3932 TODO_dump_func
/* todo_flags_finish */
3936 /* Verify that BB containing STMT as the last statement, has precisely the
3937 edge that make_eh_edges would create. */
3940 verify_eh_edges (gimple stmt
)
3942 basic_block bb
= gimple_bb (stmt
);
3943 eh_landing_pad lp
= NULL
;
3948 lp_nr
= lookup_stmt_eh_lp (stmt
);
3950 lp
= get_eh_landing_pad_from_number (lp_nr
);
3953 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3955 if (e
->flags
& EDGE_EH
)
3959 error ("BB %i has multiple EH edges", bb
->index
);
3971 error ("BB %i can not throw but has an EH edge", bb
->index
);
3977 if (!stmt_could_throw_p (stmt
))
3979 error ("BB %i last statement has incorrectly set lp", bb
->index
);
3983 if (eh_edge
== NULL
)
3985 error ("BB %i is missing an EH edge", bb
->index
);
3989 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
3991 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
3998 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4001 verify_eh_dispatch_edge (gimple stmt
)
4005 basic_block src
, dst
;
4006 bool want_fallthru
= true;
4010 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4011 src
= gimple_bb (stmt
);
4013 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4014 gcc_assert (e
->aux
== NULL
);
4019 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4021 dst
= label_to_block (c
->label
);
4022 e
= find_edge (src
, dst
);
4025 error ("BB %i is missing an edge", src
->index
);
4030 /* A catch-all handler doesn't have a fallthru. */
4031 if (c
->type_list
== NULL
)
4033 want_fallthru
= false;
4039 case ERT_ALLOWED_EXCEPTIONS
:
4040 dst
= label_to_block (r
->u
.allowed
.label
);
4041 e
= find_edge (src
, dst
);
4044 error ("BB %i is missing an edge", src
->index
);
4055 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4057 if (e
->flags
& EDGE_FALLTHRU
)
4059 if (fall_edge
!= NULL
)
4061 error ("BB %i too many fallthru edges", src
->index
);
4070 error ("BB %i has incorrect edge", src
->index
);
4074 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4076 error ("BB %i has incorrect fallthru edge", src
->index
);