1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
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"
31 #include "tree-flow.h"
32 #include "tree-dump.h"
33 #include "tree-inline.h"
34 #include "tree-iterator.h"
35 #include "tree-pass.h"
37 #include "langhooks.h"
43 /* In some instances a tree and a gimple need to be stored in a same table,
44 i.e. in hash tables. This is a structure to do this. */
45 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
47 /* Nonzero if we are using EH to handle cleanups. */
48 static int using_eh_for_cleanups_p
= 0;
51 using_eh_for_cleanups (void)
53 using_eh_for_cleanups_p
= 1;
56 /* Misc functions used in this file. */
58 /* Compare and hash for any structure which begins with a canonical
59 pointer. Assumes all pointers are interchangeable, which is sort
60 of already assumed by gcc elsewhere IIRC. */
63 struct_ptr_eq (const void *a
, const void *b
)
65 const void * const * x
= (const void * const *) a
;
66 const void * const * y
= (const void * const *) b
;
71 struct_ptr_hash (const void *a
)
73 const void * const * x
= (const void * const *) a
;
74 return (size_t)*x
>> 4;
78 /* Remember and lookup EH landing pad data for arbitrary statements.
79 Really this means any statement that could_throw_p. We could
80 stuff this information into the stmt_ann data structure, but:
82 (1) We absolutely rely on this information being kept until
83 we get to rtl. Once we're done with lowering here, if we lose
84 the information there's no way to recover it!
86 (2) There are many more statements that *cannot* throw as
87 compared to those that can. We should be saving some amount
88 of space by only allocating memory for those that can throw. */
90 /* Add statement T in function IFUN to landing pad NUM. */
93 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
95 struct throw_stmt_node
*n
;
98 gcc_assert (num
!= 0);
100 n
= GGC_NEW (struct throw_stmt_node
);
104 if (!get_eh_throw_stmt_table (ifun
))
105 set_eh_throw_stmt_table (ifun
, htab_create_ggc (31, struct_ptr_hash
,
109 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), n
, INSERT
);
114 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
117 add_stmt_to_eh_lp (gimple t
, int num
)
119 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
122 /* Add statement T to the single EH landing pad in REGION. */
125 record_stmt_eh_region (eh_region region
, gimple t
)
129 if (region
->type
== ERT_MUST_NOT_THROW
)
130 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
133 eh_landing_pad lp
= region
->landing_pads
;
135 lp
= gen_eh_landing_pad (region
);
137 gcc_assert (lp
->next_lp
== NULL
);
138 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
143 /* Remove statement T in function IFUN from its EH landing pad. */
146 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
148 struct throw_stmt_node dummy
;
151 if (!get_eh_throw_stmt_table (ifun
))
155 slot
= htab_find_slot (get_eh_throw_stmt_table (ifun
), &dummy
,
159 htab_clear_slot (get_eh_throw_stmt_table (ifun
), slot
);
167 /* Remove statement T in the current function (cfun) from its
171 remove_stmt_from_eh_lp (gimple t
)
173 return remove_stmt_from_eh_lp_fn (cfun
, t
);
176 /* Determine if statement T is inside an EH region in function IFUN.
177 Positive numbers indicate a landing pad index; negative numbers
178 indicate a MUST_NOT_THROW region index; zero indicates that the
179 statement is not recorded in the region table. */
182 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
184 struct throw_stmt_node
*p
, n
;
186 if (ifun
->eh
->throw_stmt_table
== NULL
)
190 p
= (struct throw_stmt_node
*) htab_find (ifun
->eh
->throw_stmt_table
, &n
);
191 return p
? p
->lp_nr
: 0;
194 /* Likewise, but always use the current function. */
197 lookup_stmt_eh_lp (gimple t
)
199 /* We can get called from initialized data when -fnon-call-exceptions
200 is on; prevent crash. */
203 return lookup_stmt_eh_lp_fn (cfun
, t
);
206 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
207 nodes and LABEL_DECL nodes. We will use this during the second phase to
208 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
210 struct finally_tree_node
212 /* When storing a GIMPLE_TRY, we have to record a gimple. However
213 when deciding whether a GOTO to a certain LABEL_DECL (which is a
214 tree) leaves the TRY block, its necessary to record a tree in
215 this field. Thus a treemple is used. */
220 /* Note that this table is *not* marked GTY. It is short-lived. */
221 static htab_t finally_tree
;
224 record_in_finally_tree (treemple child
, gimple parent
)
226 struct finally_tree_node
*n
;
229 n
= XNEW (struct finally_tree_node
);
233 slot
= htab_find_slot (finally_tree
, n
, INSERT
);
239 collect_finally_tree (gimple stmt
, gimple region
);
241 /* Go through the gimple sequence. Works with collect_finally_tree to
242 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
245 collect_finally_tree_1 (gimple_seq seq
, gimple region
)
247 gimple_stmt_iterator gsi
;
249 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
250 collect_finally_tree (gsi_stmt (gsi
), region
);
254 collect_finally_tree (gimple stmt
, gimple region
)
258 switch (gimple_code (stmt
))
261 temp
.t
= gimple_label_label (stmt
);
262 record_in_finally_tree (temp
, region
);
266 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
269 record_in_finally_tree (temp
, region
);
270 collect_finally_tree_1 (gimple_try_eval (stmt
), stmt
);
271 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
273 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
275 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
276 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
281 collect_finally_tree_1 (gimple_catch_handler (stmt
), region
);
284 case GIMPLE_EH_FILTER
:
285 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
289 /* A type, a decl, or some kind of statement that we're not
290 interested in. Don't walk them. */
296 /* Use the finally tree to determine if a jump from START to TARGET
297 would leave the try_finally node that START lives in. */
300 outside_finally_tree (treemple start
, gimple target
)
302 struct finally_tree_node n
, *p
;
307 p
= (struct finally_tree_node
*) htab_find (finally_tree
, &n
);
312 while (start
.g
!= target
);
317 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
318 nodes into a set of gotos, magic labels, and eh regions.
319 The eh region creation is straight-forward, but frobbing all the gotos
320 and such into shape isn't. */
322 /* The sequence into which we record all EH stuff. This will be
323 placed at the end of the function when we're all done. */
324 static gimple_seq eh_seq
;
326 /* Record whether an EH region contains something that can throw,
327 indexed by EH region number. */
328 static bitmap eh_region_may_contain_throw_map
;
330 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
331 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
332 The idea is to record a gimple statement for everything except for
333 the conditionals, which get their labels recorded. Since labels are
334 of type 'tree', we need this node to store both gimple and tree
335 objects. REPL_STMT is the sequence used to replace the goto/return
336 statement. CONT_STMT is used to store the statement that allows
337 the return/goto to jump to the original destination. */
339 struct goto_queue_node
342 gimple_seq repl_stmt
;
345 /* This is used when index >= 0 to indicate that stmt is a label (as
346 opposed to a goto stmt). */
350 /* State of the world while lowering. */
354 /* What's "current" while constructing the eh region tree. These
355 correspond to variables of the same name in cfun->eh, which we
356 don't have easy access to. */
357 eh_region cur_region
;
359 /* What's "current" for the purposes of __builtin_eh_pointer. For
360 a CATCH, this is the associated TRY. For an EH_FILTER, this is
361 the associated ALLOWED_EXCEPTIONS, etc. */
362 eh_region ehp_region
;
364 /* Processing of TRY_FINALLY requires a bit more state. This is
365 split out into a separate structure so that we don't have to
366 copy so much when processing other nodes. */
367 struct leh_tf_state
*tf
;
372 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
373 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
374 this so that outside_finally_tree can reliably reference the tree used
375 in the collect_finally_tree data structures. */
376 gimple try_finally_expr
;
379 /* While lowering a top_p usually it is expanded into multiple statements,
380 thus we need the following field to store them. */
381 gimple_seq top_p_seq
;
383 /* The state outside this try_finally node. */
384 struct leh_state
*outer
;
386 /* The exception region created for it. */
389 /* The goto queue. */
390 struct goto_queue_node
*goto_queue
;
391 size_t goto_queue_size
;
392 size_t goto_queue_active
;
394 /* Pointer map to help in searching goto_queue when it is large. */
395 struct pointer_map_t
*goto_queue_map
;
397 /* The set of unique labels seen as entries in the goto queue. */
398 VEC(tree
,heap
) *dest_array
;
400 /* A label to be added at the end of the completed transformed
401 sequence. It will be set if may_fallthru was true *at one time*,
402 though subsequent transformations may have cleared that flag. */
405 /* True if it is possible to fall out the bottom of the try block.
406 Cleared if the fallthru is converted to a goto. */
409 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
412 /* True if the finally block can receive an exception edge.
413 Cleared if the exception case is handled by code duplication. */
417 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gimple
);
419 /* Search for STMT in the goto queue. Return the replacement,
420 or null if the statement isn't in the queue. */
422 #define LARGE_GOTO_QUEUE 20
424 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
);
427 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
432 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
434 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
435 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
436 return tf
->goto_queue
[i
].repl_stmt
;
440 /* If we have a large number of entries in the goto_queue, create a
441 pointer map and use that for searching. */
443 if (!tf
->goto_queue_map
)
445 tf
->goto_queue_map
= pointer_map_create ();
446 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
448 slot
= pointer_map_insert (tf
->goto_queue_map
,
449 tf
->goto_queue
[i
].stmt
.g
);
450 gcc_assert (*slot
== NULL
);
451 *slot
= &tf
->goto_queue
[i
];
455 slot
= pointer_map_contains (tf
->goto_queue_map
, stmt
.g
);
457 return (((struct goto_queue_node
*) *slot
)->repl_stmt
);
462 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
463 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
464 then we can just splat it in, otherwise we add the new stmts immediately
465 after the GIMPLE_COND and redirect. */
468 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
469 gimple_stmt_iterator
*gsi
)
474 location_t loc
= gimple_location (gsi_stmt (*gsi
));
477 new_seq
= find_goto_replacement (tf
, temp
);
481 if (gimple_seq_singleton_p (new_seq
)
482 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
484 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
488 label
= create_artificial_label (loc
);
489 /* Set the new label for the GIMPLE_COND */
492 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
493 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
496 /* The real work of replace_goto_queue. Returns with TSI updated to
497 point to the next statement. */
499 static void replace_goto_queue_stmt_list (gimple_seq
, struct leh_tf_state
*);
502 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
503 gimple_stmt_iterator
*gsi
)
509 switch (gimple_code (stmt
))
514 seq
= find_goto_replacement (tf
, temp
);
517 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
518 gsi_remove (gsi
, false);
524 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
525 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
529 replace_goto_queue_stmt_list (gimple_try_eval (stmt
), tf
);
530 replace_goto_queue_stmt_list (gimple_try_cleanup (stmt
), tf
);
533 replace_goto_queue_stmt_list (gimple_catch_handler (stmt
), tf
);
535 case GIMPLE_EH_FILTER
:
536 replace_goto_queue_stmt_list (gimple_eh_filter_failure (stmt
), tf
);
540 /* These won't have gotos in them. */
547 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
550 replace_goto_queue_stmt_list (gimple_seq seq
, struct leh_tf_state
*tf
)
552 gimple_stmt_iterator gsi
= gsi_start (seq
);
554 while (!gsi_end_p (gsi
))
555 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
558 /* Replace all goto queue members. */
561 replace_goto_queue (struct leh_tf_state
*tf
)
563 if (tf
->goto_queue_active
== 0)
565 replace_goto_queue_stmt_list (tf
->top_p_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);
649 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
650 node, and if so record that fact in the goto queue associated with that
654 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
656 struct leh_tf_state
*tf
= state
->tf
;
662 switch (gimple_code (stmt
))
665 new_stmt
.tp
= gimple_op_ptr (stmt
, 2);
666 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_true_label (stmt
));
667 new_stmt
.tp
= gimple_op_ptr (stmt
, 3);
668 record_in_goto_queue_label (tf
, new_stmt
, gimple_cond_false_label (stmt
));
672 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
));
676 tf
->may_return
= true;
678 record_in_goto_queue (tf
, new_stmt
, -1, false);
687 #ifdef ENABLE_CHECKING
688 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
689 was in fact structured, and we've not yet done jump threading, then none
690 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
693 verify_norecord_switch_expr (struct leh_state
*state
, gimple switch_expr
)
695 struct leh_tf_state
*tf
= state
->tf
;
701 n
= gimple_switch_num_labels (switch_expr
);
703 for (i
= 0; i
< n
; ++i
)
706 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
708 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
712 #define verify_norecord_switch_expr(state, switch_expr)
715 /* Redirect a RETURN_EXPR pointed to by STMT_P to FINLAB. Place in CONT_P
716 whatever is needed to finish the return. If MOD is non-null, insert it
717 before the new branch. RETURN_VALUE_P is a cache containing a temporary
718 variable to be used in manipulating the value returned from the function. */
721 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
722 tree
*return_value_p
)
727 /* In the case of a return, the queue node must be a gimple statement. */
728 gcc_assert (!q
->is_label
);
730 ret_expr
= gimple_return_retval (q
->stmt
.g
);
734 if (!*return_value_p
)
735 *return_value_p
= ret_expr
;
737 gcc_assert (*return_value_p
== ret_expr
);
738 q
->cont_stmt
= q
->stmt
.g
;
739 /* The nasty part about redirecting the return value is that the
740 return value itself is to be computed before the FINALLY block
754 should return 0, not 1. Arrange for this to happen by copying
755 computed the return value into a local temporary. This also
756 allows us to redirect multiple return statements through the
757 same destination block; whether this is a net win or not really
758 depends, I guess, but it does make generation of the switch in
759 lower_try_finally_switch easier. */
761 if (TREE_CODE (ret_expr
) == RESULT_DECL
)
763 if (!*return_value_p
)
764 *return_value_p
= ret_expr
;
766 gcc_assert (*return_value_p
== ret_expr
);
767 q
->cont_stmt
= q
->stmt
.g
;
773 /* If we don't return a value, all return statements are the same. */
774 q
->cont_stmt
= q
->stmt
.g
;
777 q
->repl_stmt
= gimple_seq_alloc ();
780 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
782 x
= gimple_build_goto (finlab
);
783 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
786 /* Similar, but easier, for GIMPLE_GOTO. */
789 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
790 struct leh_tf_state
*tf
)
794 gcc_assert (q
->is_label
);
796 q
->repl_stmt
= gimple_seq_alloc ();
798 q
->cont_stmt
= gimple_build_goto (VEC_index (tree
, tf
->dest_array
, q
->index
));
801 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
803 x
= gimple_build_goto (finlab
);
804 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
807 /* Emit a standard landing pad sequence into SEQ for REGION. */
810 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
812 eh_landing_pad lp
= region
->landing_pads
;
816 lp
= gen_eh_landing_pad (region
);
818 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
819 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
821 x
= gimple_build_label (lp
->post_landing_pad
);
822 gimple_seq_add_stmt (seq
, x
);
825 /* Emit a RESX statement into SEQ for REGION. */
828 emit_resx (gimple_seq
*seq
, eh_region region
)
830 gimple x
= gimple_build_resx (region
->index
);
831 gimple_seq_add_stmt (seq
, x
);
833 record_stmt_eh_region (region
->outer
, x
);
836 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
839 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
841 gimple x
= gimple_build_eh_dispatch (region
->index
);
842 gimple_seq_add_stmt (seq
, x
);
845 /* Note that the current EH region may contain a throw, or a
846 call to a function which itself may contain a throw. */
849 note_eh_region_may_contain_throw (eh_region region
)
851 while (!bitmap_bit_p (eh_region_may_contain_throw_map
, region
->index
))
853 bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
);
854 region
= region
->outer
;
860 /* Check if REGION has been marked as containing a throw. If REGION is
861 NULL, this predicate is false. */
864 eh_region_may_contain_throw (eh_region r
)
866 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
869 /* We want to transform
870 try { body; } catch { stuff; }
880 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
881 should be placed before the second operand, or NULL. OVER is
882 an existing label that should be put at the exit, or NULL. */
885 frob_into_branch_around (gimple tp
, eh_region region
, tree over
)
888 gimple_seq cleanup
, result
;
889 location_t loc
= gimple_location (tp
);
891 cleanup
= gimple_try_cleanup (tp
);
892 result
= gimple_try_eval (tp
);
895 emit_post_landing_pad (&eh_seq
, region
);
897 if (gimple_seq_may_fallthru (cleanup
))
900 over
= create_artificial_label (loc
);
901 x
= gimple_build_goto (over
);
902 gimple_seq_add_stmt (&cleanup
, x
);
904 gimple_seq_add_seq (&eh_seq
, cleanup
);
908 x
= gimple_build_label (over
);
909 gimple_seq_add_stmt (&result
, x
);
914 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
915 Make sure to record all new labels found. */
918 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
)
920 gimple region
= NULL
;
923 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
926 region
= outer_state
->tf
->try_finally_expr
;
927 collect_finally_tree_1 (new_seq
, region
);
932 /* A subroutine of lower_try_finally. Create a fallthru label for
933 the given try_finally state. The only tricky bit here is that
934 we have to make sure to record the label in our outer context. */
937 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
939 tree label
= tf
->fallthru_label
;
944 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
945 tf
->fallthru_label
= label
;
949 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
955 /* A subroutine of lower_try_finally. If lang_protect_cleanup_actions
956 returns non-null, then the language requires that the exception path out
957 of a try_finally be treated specially. To wit: the code within the
958 finally block may not itself throw an exception. We have two choices here.
959 First we can duplicate the finally block and wrap it in a must_not_throw
960 region. Second, we can generate code like
965 if (fintmp == eh_edge)
966 protect_cleanup_actions;
969 where "fintmp" is the temporary used in the switch statement generation
970 alternative considered below. For the nonce, we always choose the first
973 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
976 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
977 struct leh_state
*this_state
,
978 struct leh_tf_state
*tf
)
980 tree protect_cleanup_actions
;
981 gimple_stmt_iterator gsi
;
982 bool finally_may_fallthru
;
986 /* First check for nothing to do. */
987 if (lang_protect_cleanup_actions
== NULL
)
989 protect_cleanup_actions
= lang_protect_cleanup_actions ();
990 if (protect_cleanup_actions
== NULL
)
993 finally
= gimple_try_cleanup (tf
->top_p
);
994 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
996 /* Duplicate the FINALLY block. Only need to do this for try-finally,
997 and not for cleanups. */
999 finally
= lower_try_finally_dup_block (finally
, outer_state
);
1001 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1002 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1003 to be in an enclosing scope, but needs to be implemented at this level
1004 to avoid a nesting violation (see wrap_temporary_cleanups in
1005 cp/decl.c). Since it's logically at an outer level, we should call
1006 terminate before we get to it, so strip it away before adding the
1007 MUST_NOT_THROW filter. */
1008 gsi
= gsi_start (finally
);
1010 if (gimple_code (x
) == GIMPLE_TRY
1011 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1012 && gimple_try_catch_is_cleanup (x
))
1014 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1015 gsi_remove (&gsi
, false);
1018 /* Wrap the block with protect_cleanup_actions as the action. */
1019 x
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
1020 x
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (x
),
1022 finally
= lower_eh_must_not_throw (outer_state
, x
);
1024 /* Drop all of this into the exception sequence. */
1025 emit_post_landing_pad (&eh_seq
, tf
->region
);
1026 gimple_seq_add_seq (&eh_seq
, finally
);
1027 if (finally_may_fallthru
)
1028 emit_resx (&eh_seq
, tf
->region
);
1030 /* Having now been handled, EH isn't to be considered with
1031 the rest of the outgoing edges. */
1032 tf
->may_throw
= false;
1035 /* A subroutine of lower_try_finally. We have determined that there is
1036 no fallthru edge out of the finally block. This means that there is
1037 no outgoing edge corresponding to any incoming edge. Restructure the
1038 try_finally node for this special case. */
1041 lower_try_finally_nofallthru (struct leh_state
*state
,
1042 struct leh_tf_state
*tf
)
1044 tree lab
, return_val
;
1047 struct goto_queue_node
*q
, *qe
;
1049 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1051 /* We expect that tf->top_p is a GIMPLE_TRY. */
1052 finally
= gimple_try_cleanup (tf
->top_p
);
1053 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1055 x
= gimple_build_label (lab
);
1056 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1060 qe
= q
+ tf
->goto_queue_active
;
1063 do_return_redirection (q
, lab
, NULL
, &return_val
);
1065 do_goto_redirection (q
, lab
, NULL
, tf
);
1067 replace_goto_queue (tf
);
1069 lower_eh_constructs_1 (state
, finally
);
1070 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1074 emit_post_landing_pad (&eh_seq
, tf
->region
);
1076 x
= gimple_build_goto (lab
);
1077 gimple_seq_add_stmt (&eh_seq
, x
);
1081 /* A subroutine of lower_try_finally. We have determined that there is
1082 exactly one destination of the finally block. Restructure the
1083 try_finally node for this special case. */
1086 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1088 struct goto_queue_node
*q
, *qe
;
1092 location_t loc
= gimple_location (tf
->try_finally_expr
);
1094 finally
= gimple_try_cleanup (tf
->top_p
);
1095 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1097 lower_eh_constructs_1 (state
, finally
);
1101 /* Only reachable via the exception edge. Add the given label to
1102 the head of the FINALLY block. Append a RESX at the end. */
1103 emit_post_landing_pad (&eh_seq
, tf
->region
);
1104 gimple_seq_add_seq (&eh_seq
, finally
);
1105 emit_resx (&eh_seq
, tf
->region
);
1109 if (tf
->may_fallthru
)
1111 /* Only reachable via the fallthru edge. Do nothing but let
1112 the two blocks run together; we'll fall out the bottom. */
1113 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1117 finally_label
= create_artificial_label (loc
);
1118 x
= gimple_build_label (finally_label
);
1119 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1121 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1124 qe
= q
+ tf
->goto_queue_active
;
1128 /* Reachable by return expressions only. Redirect them. */
1129 tree return_val
= NULL
;
1131 do_return_redirection (q
, finally_label
, NULL
, &return_val
);
1132 replace_goto_queue (tf
);
1136 /* Reachable by goto expressions only. Redirect them. */
1138 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1139 replace_goto_queue (tf
);
1141 if (VEC_index (tree
, tf
->dest_array
, 0) == tf
->fallthru_label
)
1143 /* Reachable by goto to fallthru label only. Redirect it
1144 to the new label (already created, sadly), and do not
1145 emit the final branch out, or the fallthru label. */
1146 tf
->fallthru_label
= NULL
;
1151 /* Place the original return/goto to the original destination
1152 immediately after the finally block. */
1153 x
= tf
->goto_queue
[0].cont_stmt
;
1154 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1155 maybe_record_in_goto_queue (state
, x
);
1158 /* A subroutine of lower_try_finally. There are multiple edges incoming
1159 and outgoing from the finally block. Implement this by duplicating the
1160 finally block for every destination. */
1163 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1166 gimple_seq new_stmt
;
1170 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1172 finally
= gimple_try_cleanup (tf
->top_p
);
1173 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1176 if (tf
->may_fallthru
)
1178 seq
= lower_try_finally_dup_block (finally
, state
);
1179 lower_eh_constructs_1 (state
, seq
);
1180 gimple_seq_add_seq (&new_stmt
, seq
);
1182 tmp
= lower_try_finally_fallthru_label (tf
);
1183 x
= gimple_build_goto (tmp
);
1184 gimple_seq_add_stmt (&new_stmt
, x
);
1189 seq
= lower_try_finally_dup_block (finally
, state
);
1190 lower_eh_constructs_1 (state
, seq
);
1192 emit_post_landing_pad (&eh_seq
, tf
->region
);
1193 gimple_seq_add_seq (&eh_seq
, seq
);
1194 emit_resx (&eh_seq
, tf
->region
);
1199 struct goto_queue_node
*q
, *qe
;
1200 tree return_val
= NULL
;
1201 int return_index
, index
;
1204 struct goto_queue_node
*q
;
1208 return_index
= VEC_length (tree
, tf
->dest_array
);
1209 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1212 qe
= q
+ tf
->goto_queue_active
;
1215 index
= q
->index
< 0 ? return_index
: q
->index
;
1217 if (!labels
[index
].q
)
1218 labels
[index
].q
= q
;
1221 for (index
= 0; index
< return_index
+ 1; index
++)
1225 q
= labels
[index
].q
;
1229 lab
= labels
[index
].label
1230 = create_artificial_label (tf_loc
);
1232 if (index
== return_index
)
1233 do_return_redirection (q
, lab
, NULL
, &return_val
);
1235 do_goto_redirection (q
, lab
, NULL
, tf
);
1237 x
= gimple_build_label (lab
);
1238 gimple_seq_add_stmt (&new_stmt
, x
);
1240 seq
= lower_try_finally_dup_block (finally
, state
);
1241 lower_eh_constructs_1 (state
, seq
);
1242 gimple_seq_add_seq (&new_stmt
, seq
);
1244 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1245 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1248 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1252 index
= q
->index
< 0 ? return_index
: q
->index
;
1254 if (labels
[index
].q
== q
)
1257 lab
= labels
[index
].label
;
1259 if (index
== return_index
)
1260 do_return_redirection (q
, lab
, NULL
, &return_val
);
1262 do_goto_redirection (q
, lab
, NULL
, tf
);
1265 replace_goto_queue (tf
);
1269 /* Need to link new stmts after running replace_goto_queue due
1270 to not wanting to process the same goto stmts twice. */
1271 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1274 /* A subroutine of lower_try_finally. There are multiple edges incoming
1275 and outgoing from the finally block. Implement this by instrumenting
1276 each incoming edge and creating a switch statement at the end of the
1277 finally block that branches to the appropriate destination. */
1280 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1282 struct goto_queue_node
*q
, *qe
;
1283 tree return_val
= NULL
;
1284 tree finally_tmp
, finally_label
;
1285 int return_index
, eh_index
, fallthru_index
;
1286 int nlabels
, ndests
, j
, last_case_index
;
1288 VEC (tree
,heap
) *case_label_vec
;
1289 gimple_seq switch_body
;
1294 struct pointer_map_t
*cont_map
= NULL
;
1295 /* The location of the TRY_FINALLY stmt. */
1296 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1297 /* The location of the finally block. */
1298 location_t finally_loc
;
1300 switch_body
= gimple_seq_alloc ();
1302 /* Mash the TRY block to the head of the chain. */
1303 finally
= gimple_try_cleanup (tf
->top_p
);
1304 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1306 /* The location of the finally is either the last stmt in the finally
1307 block or the location of the TRY_FINALLY itself. */
1308 finally_loc
= gimple_seq_last_stmt (tf
->top_p_seq
) != NULL
?
1309 gimple_location (gimple_seq_last_stmt (tf
->top_p_seq
))
1312 /* Lower the finally block itself. */
1313 lower_eh_constructs_1 (state
, finally
);
1315 /* Prepare for switch statement generation. */
1316 nlabels
= VEC_length (tree
, tf
->dest_array
);
1317 return_index
= nlabels
;
1318 eh_index
= return_index
+ tf
->may_return
;
1319 fallthru_index
= eh_index
+ tf
->may_throw
;
1320 ndests
= fallthru_index
+ tf
->may_fallthru
;
1322 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1323 finally_label
= create_artificial_label (finally_loc
);
1325 /* We use VEC_quick_push on case_label_vec throughout this function,
1326 since we know the size in advance and allocate precisely as muce
1328 case_label_vec
= VEC_alloc (tree
, heap
, ndests
);
1330 last_case_index
= 0;
1332 /* Begin inserting code for getting to the finally block. Things
1333 are done in this order to correspond to the sequence the code is
1336 if (tf
->may_fallthru
)
1338 x
= gimple_build_assign (finally_tmp
,
1339 build_int_cst (NULL
, fallthru_index
));
1340 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1342 last_case
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1343 build_int_cst (NULL
, fallthru_index
),
1344 NULL
, create_artificial_label (tf_loc
));
1345 VEC_quick_push (tree
, case_label_vec
, last_case
);
1348 x
= gimple_build_label (CASE_LABEL (last_case
));
1349 gimple_seq_add_stmt (&switch_body
, x
);
1351 tmp
= lower_try_finally_fallthru_label (tf
);
1352 x
= gimple_build_goto (tmp
);
1353 gimple_seq_add_stmt (&switch_body
, x
);
1358 emit_post_landing_pad (&eh_seq
, tf
->region
);
1360 x
= gimple_build_assign (finally_tmp
,
1361 build_int_cst (NULL
, eh_index
));
1362 gimple_seq_add_stmt (&eh_seq
, x
);
1364 x
= gimple_build_goto (finally_label
);
1365 gimple_seq_add_stmt (&eh_seq
, x
);
1367 last_case
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1368 build_int_cst (NULL
, eh_index
),
1369 NULL
, create_artificial_label (tf_loc
));
1370 VEC_quick_push (tree
, case_label_vec
, last_case
);
1373 x
= gimple_build_label (CASE_LABEL (last_case
));
1374 gimple_seq_add_stmt (&eh_seq
, x
);
1375 emit_resx (&eh_seq
, tf
->region
);
1378 x
= gimple_build_label (finally_label
);
1379 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1381 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1383 /* Redirect each incoming goto edge. */
1385 qe
= q
+ tf
->goto_queue_active
;
1386 j
= last_case_index
+ tf
->may_return
;
1387 /* Prepare the assignments to finally_tmp that are executed upon the
1388 entrance through a particular edge. */
1393 unsigned int case_index
;
1395 mod
= gimple_seq_alloc ();
1399 x
= gimple_build_assign (finally_tmp
,
1400 build_int_cst (NULL
, return_index
));
1401 gimple_seq_add_stmt (&mod
, x
);
1402 do_return_redirection (q
, finally_label
, mod
, &return_val
);
1403 switch_id
= return_index
;
1407 x
= gimple_build_assign (finally_tmp
,
1408 build_int_cst (NULL
, q
->index
));
1409 gimple_seq_add_stmt (&mod
, x
);
1410 do_goto_redirection (q
, finally_label
, mod
, tf
);
1411 switch_id
= q
->index
;
1414 case_index
= j
+ q
->index
;
1415 if (VEC_length (tree
, case_label_vec
) <= case_index
1416 || !VEC_index (tree
, case_label_vec
, case_index
))
1420 case_lab
= build3 (CASE_LABEL_EXPR
, void_type_node
,
1421 build_int_cst (NULL
, switch_id
),
1423 /* We store the cont_stmt in the pointer map, so that we can recover
1424 it in the loop below. We don't create the new label while
1425 walking the goto_queue because pointers don't offer a stable
1428 cont_map
= pointer_map_create ();
1429 slot
= pointer_map_insert (cont_map
, case_lab
);
1430 *slot
= q
->cont_stmt
;
1431 VEC_quick_push (tree
, case_label_vec
, case_lab
);
1434 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1440 last_case
= VEC_index (tree
, case_label_vec
, j
);
1442 gcc_assert (last_case
);
1443 gcc_assert (cont_map
);
1445 slot
= pointer_map_contains (cont_map
, last_case
);
1446 /* As the comment above suggests, CASE_LABEL (last_case) was just a
1447 placeholder, it does not store an actual label, yet. */
1449 cont_stmt
= *(gimple
*) slot
;
1451 label
= create_artificial_label (tf_loc
);
1452 CASE_LABEL (last_case
) = label
;
1454 x
= gimple_build_label (label
);
1455 gimple_seq_add_stmt (&switch_body
, x
);
1456 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1457 maybe_record_in_goto_queue (state
, cont_stmt
);
1460 pointer_map_destroy (cont_map
);
1462 replace_goto_queue (tf
);
1464 /* Make sure that the last case is the default label, as one is required.
1465 Then sort the labels, which is also required in GIMPLE. */
1466 CASE_LOW (last_case
) = NULL
;
1467 sort_case_labels (case_label_vec
);
1469 /* Build the switch statement, setting last_case to be the default
1471 switch_stmt
= gimple_build_switch_vec (finally_tmp
, last_case
,
1473 gimple_set_location (switch_stmt
, finally_loc
);
1475 /* Need to link SWITCH_STMT after running replace_goto_queue
1476 due to not wanting to process the same goto stmts twice. */
1477 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1478 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1481 /* Decide whether or not we are going to duplicate the finally block.
1482 There are several considerations.
1484 First, if this is Java, then the finally block contains code
1485 written by the user. It has line numbers associated with it,
1486 so duplicating the block means it's difficult to set a breakpoint.
1487 Since controlling code generation via -g is verboten, we simply
1488 never duplicate code without optimization.
1490 Second, we'd like to prevent egregious code growth. One way to
1491 do this is to estimate the size of the finally block, multiply
1492 that by the number of copies we'd need to make, and compare against
1493 the estimate of the size of the switch machinery we'd have to add. */
1496 decide_copy_try_finally (int ndests
, gimple_seq finally
)
1498 int f_estimate
, sw_estimate
;
1503 /* Finally estimate N times, plus N gotos. */
1504 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1505 f_estimate
= (f_estimate
+ 1) * ndests
;
1507 /* Switch statement (cost 10), N variable assignments, N gotos. */
1508 sw_estimate
= 10 + 2 * ndests
;
1510 /* Optimize for size clearly wants our best guess. */
1511 if (optimize_function_for_size_p (cfun
))
1512 return f_estimate
< sw_estimate
;
1514 /* ??? These numbers are completely made up so far. */
1516 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1518 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1522 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1523 to a sequence of labels and blocks, plus the exception region trees
1524 that record all the magic. This is complicated by the need to
1525 arrange for the FINALLY block to be executed on all exits. */
1528 lower_try_finally (struct leh_state
*state
, gimple tp
)
1530 struct leh_tf_state this_tf
;
1531 struct leh_state this_state
;
1534 /* Process the try block. */
1536 memset (&this_tf
, 0, sizeof (this_tf
));
1537 this_tf
.try_finally_expr
= tp
;
1539 this_tf
.outer
= state
;
1540 if (using_eh_for_cleanups_p
)
1541 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1543 this_tf
.region
= NULL
;
1545 this_state
.cur_region
= this_tf
.region
;
1546 this_state
.ehp_region
= state
->ehp_region
;
1547 this_state
.tf
= &this_tf
;
1549 lower_eh_constructs_1 (&this_state
, gimple_try_eval(tp
));
1551 /* Determine if the try block is escaped through the bottom. */
1552 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1554 /* Determine if any exceptions are possible within the try block. */
1555 if (using_eh_for_cleanups_p
)
1556 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1557 if (this_tf
.may_throw
)
1558 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1560 /* Determine how many edges (still) reach the finally block. Or rather,
1561 how many destinations are reached by the finally block. Use this to
1562 determine how we process the finally block itself. */
1564 ndests
= VEC_length (tree
, this_tf
.dest_array
);
1565 ndests
+= this_tf
.may_fallthru
;
1566 ndests
+= this_tf
.may_return
;
1567 ndests
+= this_tf
.may_throw
;
1569 /* If the FINALLY block is not reachable, dike it out. */
1572 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1573 gimple_try_set_cleanup (tp
, NULL
);
1575 /* If the finally block doesn't fall through, then any destination
1576 we might try to impose there isn't reached either. There may be
1577 some minor amount of cleanup and redirection still needed. */
1578 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1579 lower_try_finally_nofallthru (state
, &this_tf
);
1581 /* We can easily special-case redirection to a single destination. */
1582 else if (ndests
== 1)
1583 lower_try_finally_onedest (state
, &this_tf
);
1584 else if (decide_copy_try_finally (ndests
, gimple_try_cleanup (tp
)))
1585 lower_try_finally_copy (state
, &this_tf
);
1587 lower_try_finally_switch (state
, &this_tf
);
1589 /* If someone requested we add a label at the end of the transformed
1591 if (this_tf
.fallthru_label
)
1593 /* This must be reached only if ndests == 0. */
1594 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1595 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1598 VEC_free (tree
, heap
, this_tf
.dest_array
);
1599 if (this_tf
.goto_queue
)
1600 free (this_tf
.goto_queue
);
1601 if (this_tf
.goto_queue_map
)
1602 pointer_map_destroy (this_tf
.goto_queue_map
);
1604 return this_tf
.top_p_seq
;
1607 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1608 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1609 exception region trees that records all the magic. */
1612 lower_catch (struct leh_state
*state
, gimple tp
)
1614 eh_region try_region
= NULL
;
1615 struct leh_state this_state
= *state
;
1616 gimple_stmt_iterator gsi
;
1620 location_t try_catch_loc
= gimple_location (tp
);
1622 if (flag_exceptions
)
1624 try_region
= gen_eh_region_try (state
->cur_region
);
1625 this_state
.cur_region
= try_region
;
1628 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1630 if (!eh_region_may_contain_throw (try_region
))
1631 return gimple_try_eval (tp
);
1634 emit_eh_dispatch (&new_seq
, try_region
);
1635 emit_resx (&new_seq
, try_region
);
1637 this_state
.cur_region
= state
->cur_region
;
1638 this_state
.ehp_region
= try_region
;
1641 for (gsi
= gsi_start (gimple_try_cleanup (tp
));
1649 gcatch
= gsi_stmt (gsi
);
1650 c
= gen_eh_region_catch (try_region
, gimple_catch_types (gcatch
));
1652 handler
= gimple_catch_handler (gcatch
);
1653 lower_eh_constructs_1 (&this_state
, handler
);
1655 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1656 x
= gimple_build_label (c
->label
);
1657 gimple_seq_add_stmt (&new_seq
, x
);
1659 gimple_seq_add_seq (&new_seq
, handler
);
1661 if (gimple_seq_may_fallthru (new_seq
))
1664 out_label
= create_artificial_label (try_catch_loc
);
1666 x
= gimple_build_goto (out_label
);
1667 gimple_seq_add_stmt (&new_seq
, x
);
1671 gimple_try_set_cleanup (tp
, new_seq
);
1673 return frob_into_branch_around (tp
, try_region
, out_label
);
1676 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1677 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1678 region trees that record all the magic. */
1681 lower_eh_filter (struct leh_state
*state
, gimple tp
)
1683 struct leh_state this_state
= *state
;
1684 eh_region this_region
= NULL
;
1688 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1690 if (flag_exceptions
)
1692 this_region
= gen_eh_region_allowed (state
->cur_region
,
1693 gimple_eh_filter_types (inner
));
1694 this_state
.cur_region
= this_region
;
1697 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1699 if (!eh_region_may_contain_throw (this_region
))
1700 return gimple_try_eval (tp
);
1703 this_state
.cur_region
= state
->cur_region
;
1704 this_state
.ehp_region
= this_region
;
1706 emit_eh_dispatch (&new_seq
, this_region
);
1707 emit_resx (&new_seq
, this_region
);
1709 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1710 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1711 gimple_seq_add_stmt (&new_seq
, x
);
1713 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure (inner
));
1714 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1716 gimple_try_set_cleanup (tp
, new_seq
);
1718 return frob_into_branch_around (tp
, this_region
, NULL
);
1721 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1722 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1723 plus the exception region trees that record all the magic. */
1726 lower_eh_must_not_throw (struct leh_state
*state
, gimple tp
)
1728 struct leh_state this_state
= *state
;
1730 if (flag_exceptions
)
1732 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1733 eh_region this_region
;
1735 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1736 this_region
->u
.must_not_throw
.failure_decl
1737 = gimple_eh_must_not_throw_fndecl (inner
);
1738 this_region
->u
.must_not_throw
.failure_loc
= gimple_location (tp
);
1740 /* In order to get mangling applied to this decl, we must mark it
1741 used now. Otherwise, pass_ipa_free_lang_data won't think it
1743 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1745 this_state
.cur_region
= this_region
;
1748 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1750 return gimple_try_eval (tp
);
1753 /* Implement a cleanup expression. This is similar to try-finally,
1754 except that we only execute the cleanup block for exception edges. */
1757 lower_cleanup (struct leh_state
*state
, gimple tp
)
1759 struct leh_state this_state
= *state
;
1760 eh_region this_region
= NULL
;
1761 struct leh_tf_state fake_tf
;
1764 if (flag_exceptions
)
1766 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1767 this_state
.cur_region
= this_region
;
1770 lower_eh_constructs_1 (&this_state
, gimple_try_eval (tp
));
1772 if (!eh_region_may_contain_throw (this_region
))
1773 return gimple_try_eval (tp
);
1775 /* Build enough of a try-finally state so that we can reuse
1776 honor_protect_cleanup_actions. */
1777 memset (&fake_tf
, 0, sizeof (fake_tf
));
1778 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1779 fake_tf
.outer
= state
;
1780 fake_tf
.region
= this_region
;
1781 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1782 fake_tf
.may_throw
= true;
1784 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1786 if (fake_tf
.may_throw
)
1788 /* In this case honor_protect_cleanup_actions had nothing to do,
1789 and we should process this normally. */
1790 lower_eh_constructs_1 (state
, gimple_try_cleanup (tp
));
1791 result
= frob_into_branch_around (tp
, this_region
,
1792 fake_tf
.fallthru_label
);
1796 /* In this case honor_protect_cleanup_actions did nearly all of
1797 the work. All we have left is to append the fallthru_label. */
1799 result
= gimple_try_eval (tp
);
1800 if (fake_tf
.fallthru_label
)
1802 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1803 gimple_seq_add_stmt (&result
, x
);
1809 /* Main loop for lowering eh constructs. Also moves gsi to the next
1813 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1817 gimple stmt
= gsi_stmt (*gsi
);
1819 switch (gimple_code (stmt
))
1823 tree fndecl
= gimple_call_fndecl (stmt
);
1826 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1827 switch (DECL_FUNCTION_CODE (fndecl
))
1829 case BUILT_IN_EH_POINTER
:
1830 /* The front end may have generated a call to
1831 __builtin_eh_pointer (0) within a catch region. Replace
1832 this zero argument with the current catch region number. */
1833 if (state
->ehp_region
)
1835 tree nr
= build_int_cst (NULL
, state
->ehp_region
->index
);
1836 gimple_call_set_arg (stmt
, 0, nr
);
1840 /* The user has dome something silly. Remove it. */
1841 rhs
= build_int_cst (ptr_type_node
, 0);
1846 case BUILT_IN_EH_FILTER
:
1847 /* ??? This should never appear, but since it's a builtin it
1848 is accessible to abuse by users. Just remove it and
1849 replace the use with the arbitrary value zero. */
1850 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
1852 lhs
= gimple_call_lhs (stmt
);
1853 x
= gimple_build_assign (lhs
, rhs
);
1854 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
1857 case BUILT_IN_EH_COPY_VALUES
:
1858 /* Likewise this should not appear. Remove it. */
1859 gsi_remove (gsi
, true);
1869 /* If the stmt can throw use a new temporary for the assignment
1870 to a LHS. This makes sure the old value of the LHS is
1871 available on the EH edge. */
1872 if (stmt_could_throw_p (stmt
)
1873 && gimple_has_lhs (stmt
)
1874 && !tree_could_throw_p (gimple_get_lhs (stmt
))
1875 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
1877 tree lhs
= gimple_get_lhs (stmt
);
1878 tree tmp
= create_tmp_var (TREE_TYPE (lhs
), NULL
);
1879 gimple s
= gimple_build_assign (lhs
, tmp
);
1880 gimple_set_location (s
, gimple_location (stmt
));
1881 gimple_set_block (s
, gimple_block (stmt
));
1882 gimple_set_lhs (stmt
, tmp
);
1883 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
1884 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
1885 DECL_GIMPLE_REG_P (tmp
) = 1;
1886 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
1888 /* Look for things that can throw exceptions, and record them. */
1889 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
1891 record_stmt_eh_region (state
->cur_region
, stmt
);
1892 note_eh_region_may_contain_throw (state
->cur_region
);
1899 maybe_record_in_goto_queue (state
, stmt
);
1903 verify_norecord_switch_expr (state
, stmt
);
1907 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
1908 replace
= lower_try_finally (state
, stmt
);
1911 x
= gimple_seq_first_stmt (gimple_try_cleanup (stmt
));
1914 replace
= gimple_try_eval (stmt
);
1915 lower_eh_constructs_1 (state
, replace
);
1918 switch (gimple_code (x
))
1921 replace
= lower_catch (state
, stmt
);
1923 case GIMPLE_EH_FILTER
:
1924 replace
= lower_eh_filter (state
, stmt
);
1926 case GIMPLE_EH_MUST_NOT_THROW
:
1927 replace
= lower_eh_must_not_throw (state
, stmt
);
1930 replace
= lower_cleanup (state
, stmt
);
1935 /* Remove the old stmt and insert the transformed sequence
1937 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
1938 gsi_remove (gsi
, true);
1940 /* Return since we don't want gsi_next () */
1944 /* A type, a decl, or some kind of statement that we're not
1945 interested in. Don't walk them. */
1952 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
1955 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq seq
)
1957 gimple_stmt_iterator gsi
;
1958 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
);)
1959 lower_eh_constructs_2 (state
, &gsi
);
1963 lower_eh_constructs (void)
1965 struct leh_state null_state
;
1968 bodyp
= gimple_body (current_function_decl
);
1972 finally_tree
= htab_create (31, struct_ptr_hash
, struct_ptr_eq
, free
);
1973 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
1974 memset (&null_state
, 0, sizeof (null_state
));
1976 collect_finally_tree_1 (bodyp
, NULL
);
1977 lower_eh_constructs_1 (&null_state
, bodyp
);
1979 /* We assume there's a return statement, or something, at the end of
1980 the function, and thus ploping the EH sequence afterward won't
1982 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
1983 gimple_seq_add_seq (&bodyp
, eh_seq
);
1985 /* We assume that since BODYP already existed, adding EH_SEQ to it
1986 didn't change its value, and we don't have to re-set the function. */
1987 gcc_assert (bodyp
== gimple_body (current_function_decl
));
1989 htab_delete (finally_tree
);
1990 BITMAP_FREE (eh_region_may_contain_throw_map
);
1993 /* If this function needs a language specific EH personality routine
1994 and the frontend didn't already set one do so now. */
1995 if (function_needs_eh_personality (cfun
) == eh_personality_lang
1996 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
1997 DECL_FUNCTION_PERSONALITY (current_function_decl
)
1998 = lang_hooks
.eh_personality ();
2003 struct gimple_opt_pass pass_lower_eh
=
2009 lower_eh_constructs
, /* execute */
2012 0, /* static_pass_number */
2013 TV_TREE_EH
, /* tv_id */
2014 PROP_gimple_lcf
, /* properties_required */
2015 PROP_gimple_leh
, /* properties_provided */
2016 0, /* properties_destroyed */
2017 0, /* todo_flags_start */
2018 TODO_dump_func
/* todo_flags_finish */
2022 /* Create the multiple edges from an EH_DISPATCH statement to all of
2023 the possible handlers for its EH region. Return true if there's
2024 no fallthru edge; false if there is. */
2027 make_eh_dispatch_edges (gimple stmt
)
2031 basic_block src
, dst
;
2033 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2034 src
= gimple_bb (stmt
);
2039 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2041 dst
= label_to_block (c
->label
);
2042 make_edge (src
, dst
, 0);
2044 /* A catch-all handler doesn't have a fallthru. */
2045 if (c
->type_list
== NULL
)
2050 case ERT_ALLOWED_EXCEPTIONS
:
2051 dst
= label_to_block (r
->u
.allowed
.label
);
2052 make_edge (src
, dst
, 0);
2062 /* Create the single EH edge from STMT to its nearest landing pad,
2063 if there is such a landing pad within the current function. */
2066 make_eh_edges (gimple stmt
)
2068 basic_block src
, dst
;
2072 lp_nr
= lookup_stmt_eh_lp (stmt
);
2076 lp
= get_eh_landing_pad_from_number (lp_nr
);
2077 gcc_assert (lp
!= NULL
);
2079 src
= gimple_bb (stmt
);
2080 dst
= label_to_block (lp
->post_landing_pad
);
2081 make_edge (src
, dst
, EDGE_EH
);
2084 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2085 do not actually perform the final edge redirection.
2087 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2088 we intend to change the destination EH region as well; this means
2089 EH_LANDING_PAD_NR must already be set on the destination block label.
2090 If false, we're being called from generic cfg manipulation code and we
2091 should preserve our place within the region tree. */
2094 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2096 eh_landing_pad old_lp
, new_lp
;
2099 int old_lp_nr
, new_lp_nr
;
2100 tree old_label
, new_label
;
2104 old_bb
= edge_in
->dest
;
2105 old_label
= gimple_block_label (old_bb
);
2106 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2107 gcc_assert (old_lp_nr
> 0);
2108 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2110 throw_stmt
= last_stmt (edge_in
->src
);
2111 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2113 new_label
= gimple_block_label (new_bb
);
2115 /* Look for an existing region that might be using NEW_BB already. */
2116 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2119 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2120 gcc_assert (new_lp
);
2122 /* Unless CHANGE_REGION is true, the new and old landing pad
2123 had better be associated with the same EH region. */
2124 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2129 gcc_assert (!change_region
);
2132 /* Notice when we redirect the last EH edge away from OLD_BB. */
2133 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2134 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2139 /* NEW_LP already exists. If there are still edges into OLD_LP,
2140 there's nothing to do with the EH tree. If there are no more
2141 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2142 If CHANGE_REGION is true, then our caller is expecting to remove
2144 if (e
== NULL
&& !change_region
)
2145 remove_eh_landing_pad (old_lp
);
2149 /* No correct landing pad exists. If there are no more edges
2150 into OLD_LP, then we can simply re-use the existing landing pad.
2151 Otherwise, we have to create a new landing pad. */
2154 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2158 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2159 new_lp
->post_landing_pad
= new_label
;
2160 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2163 /* Maybe move the throwing statement to the new region. */
2164 if (old_lp
!= new_lp
)
2166 remove_stmt_from_eh_lp (throw_stmt
);
2167 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2171 /* Redirect EH edge E to NEW_BB. */
2174 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2176 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2177 return ssa_redirect_edge (edge_in
, new_bb
);
2180 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2181 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2182 The actual edge update will happen in the caller. */
2185 redirect_eh_dispatch_edge (gimple stmt
, edge e
, basic_block new_bb
)
2187 tree new_lab
= gimple_block_label (new_bb
);
2188 bool any_changed
= false;
2193 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2197 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2199 old_bb
= label_to_block (c
->label
);
2200 if (old_bb
== e
->dest
)
2208 case ERT_ALLOWED_EXCEPTIONS
:
2209 old_bb
= label_to_block (r
->u
.allowed
.label
);
2210 gcc_assert (old_bb
== e
->dest
);
2211 r
->u
.allowed
.label
= new_lab
;
2219 gcc_assert (any_changed
);
2222 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2225 operation_could_trap_helper_p (enum tree_code op
,
2236 case TRUNC_DIV_EXPR
:
2238 case FLOOR_DIV_EXPR
:
2239 case ROUND_DIV_EXPR
:
2240 case EXACT_DIV_EXPR
:
2242 case FLOOR_MOD_EXPR
:
2243 case ROUND_MOD_EXPR
:
2244 case TRUNC_MOD_EXPR
:
2246 if (honor_snans
|| honor_trapv
)
2249 return flag_trapping_math
;
2250 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2259 /* Some floating point comparisons may trap. */
2264 case UNORDERED_EXPR
:
2274 case FIX_TRUNC_EXPR
:
2275 /* Conversion of floating point might trap. */
2281 /* These operations don't trap with floating point. */
2289 /* Any floating arithmetic may trap. */
2290 if (fp_operation
&& flag_trapping_math
)
2297 /* Any floating arithmetic may trap. */
2298 if (fp_operation
&& flag_trapping_math
)
2306 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2307 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2308 type operands that may trap. If OP is a division operator, DIVISOR contains
2309 the value of the divisor. */
2312 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2315 bool honor_nans
= (fp_operation
&& flag_trapping_math
2316 && !flag_finite_math_only
);
2317 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2320 if (TREE_CODE_CLASS (op
) != tcc_comparison
2321 && TREE_CODE_CLASS (op
) != tcc_unary
2322 && TREE_CODE_CLASS (op
) != tcc_binary
)
2325 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2326 honor_nans
, honor_snans
, divisor
,
2330 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2331 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2332 This routine expects only GIMPLE lhs or rhs input. */
2335 tree_could_trap_p (tree expr
)
2337 enum tree_code code
;
2338 bool fp_operation
= false;
2339 bool honor_trapv
= false;
2340 tree t
, base
, div
= NULL_TREE
;
2345 code
= TREE_CODE (expr
);
2346 t
= TREE_TYPE (expr
);
2350 if (COMPARISON_CLASS_P (expr
))
2351 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2353 fp_operation
= FLOAT_TYPE_P (t
);
2354 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2357 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2358 div
= TREE_OPERAND (expr
, 1);
2359 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2365 case TARGET_MEM_REF
:
2366 /* For TARGET_MEM_REFs use the information based on the original
2368 expr
= TMR_ORIGINAL (expr
);
2369 code
= TREE_CODE (expr
);
2376 case VIEW_CONVERT_EXPR
:
2377 case WITH_SIZE_EXPR
:
2378 expr
= TREE_OPERAND (expr
, 0);
2379 code
= TREE_CODE (expr
);
2382 case ARRAY_RANGE_REF
:
2383 base
= TREE_OPERAND (expr
, 0);
2384 if (tree_could_trap_p (base
))
2386 if (TREE_THIS_NOTRAP (expr
))
2388 return !range_in_array_bounds_p (expr
);
2391 base
= TREE_OPERAND (expr
, 0);
2392 if (tree_could_trap_p (base
))
2394 if (TREE_THIS_NOTRAP (expr
))
2396 return !in_array_bounds_p (expr
);
2399 case ALIGN_INDIRECT_REF
:
2400 case MISALIGNED_INDIRECT_REF
:
2401 return !TREE_THIS_NOTRAP (expr
);
2404 return TREE_THIS_VOLATILE (expr
);
2407 t
= get_callee_fndecl (expr
);
2408 /* Assume that calls to weak functions may trap. */
2409 if (!t
|| !DECL_P (t
) || DECL_WEAK (t
))
2419 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2420 an assignment or a conditional) may throw. */
2423 stmt_could_throw_1_p (gimple stmt
)
2425 enum tree_code code
= gimple_expr_code (stmt
);
2426 bool honor_nans
= false;
2427 bool honor_snans
= false;
2428 bool fp_operation
= false;
2429 bool honor_trapv
= false;
2434 if (TREE_CODE_CLASS (code
) == tcc_comparison
2435 || TREE_CODE_CLASS (code
) == tcc_unary
2436 || TREE_CODE_CLASS (code
) == tcc_binary
)
2438 t
= gimple_expr_type (stmt
);
2439 fp_operation
= FLOAT_TYPE_P (t
);
2442 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2443 honor_snans
= flag_signaling_nans
!= 0;
2445 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2449 /* Check if the main expression may trap. */
2450 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2451 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2452 honor_nans
, honor_snans
, t
,
2457 /* If the expression does not trap, see if any of the individual operands may
2459 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2460 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2467 /* Return true if statement STMT could throw an exception. */
2470 stmt_could_throw_p (gimple stmt
)
2472 if (!flag_exceptions
)
2475 /* The only statements that can throw an exception are assignments,
2476 conditionals, calls, resx, and asms. */
2477 switch (gimple_code (stmt
))
2483 return !gimple_call_nothrow_p (stmt
);
2487 if (!flag_non_call_exceptions
)
2489 return stmt_could_throw_1_p (stmt
);
2492 if (!flag_non_call_exceptions
)
2494 return gimple_asm_volatile_p (stmt
);
2502 /* Return true if expression T could throw an exception. */
2505 tree_could_throw_p (tree t
)
2507 if (!flag_exceptions
)
2509 if (TREE_CODE (t
) == MODIFY_EXPR
)
2511 if (flag_non_call_exceptions
2512 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2514 t
= TREE_OPERAND (t
, 1);
2517 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2518 t
= TREE_OPERAND (t
, 0);
2519 if (TREE_CODE (t
) == CALL_EXPR
)
2520 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2521 if (flag_non_call_exceptions
)
2522 return tree_could_trap_p (t
);
2526 /* Return true if STMT can throw an exception that is not caught within
2527 the current function (CFUN). */
2530 stmt_can_throw_external (gimple stmt
)
2534 if (!stmt_could_throw_p (stmt
))
2537 lp_nr
= lookup_stmt_eh_lp (stmt
);
2541 /* Return true if STMT can throw an exception that is caught within
2542 the current function (CFUN). */
2545 stmt_can_throw_internal (gimple stmt
)
2549 if (!stmt_could_throw_p (stmt
))
2552 lp_nr
= lookup_stmt_eh_lp (stmt
);
2556 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2557 remove any entry it might have from the EH table. Return true if
2558 any change was made. */
2561 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2563 if (stmt_could_throw_p (stmt
))
2565 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2568 /* Likewise, but always use the current function. */
2571 maybe_clean_eh_stmt (gimple stmt
)
2573 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2576 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2577 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2578 in the table if it should be in there. Return TRUE if a replacement was
2579 done that my require an EH edge purge. */
2582 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2584 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2588 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2590 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2593 remove_stmt_from_eh_lp (old_stmt
);
2594 if (new_stmt_could_throw
)
2596 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2606 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statment NEW_STMT
2607 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2608 operand is the return value of duplicate_eh_regions. */
2611 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2612 struct function
*old_fun
, gimple old_stmt
,
2613 struct pointer_map_t
*map
, int default_lp_nr
)
2615 int old_lp_nr
, new_lp_nr
;
2618 if (!stmt_could_throw_p (new_stmt
))
2621 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2624 if (default_lp_nr
== 0)
2626 new_lp_nr
= default_lp_nr
;
2628 else if (old_lp_nr
> 0)
2630 eh_landing_pad old_lp
, new_lp
;
2632 old_lp
= VEC_index (eh_landing_pad
, old_fun
->eh
->lp_array
, old_lp_nr
);
2633 slot
= pointer_map_contains (map
, old_lp
);
2634 new_lp
= (eh_landing_pad
) *slot
;
2635 new_lp_nr
= new_lp
->index
;
2639 eh_region old_r
, new_r
;
2641 old_r
= VEC_index (eh_region
, old_fun
->eh
->region_array
, -old_lp_nr
);
2642 slot
= pointer_map_contains (map
, old_r
);
2643 new_r
= (eh_region
) *slot
;
2644 new_lp_nr
= -new_r
->index
;
2647 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2651 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2652 and thus no remapping is required. */
2655 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2659 if (!stmt_could_throw_p (new_stmt
))
2662 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2666 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2670 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2671 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2672 this only handles handlers consisting of a single call, as that's the
2673 important case for C++: a destructor call for a particular object showing
2674 up in multiple handlers. */
2677 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2679 gimple_stmt_iterator gsi
;
2683 gsi
= gsi_start (oneh
);
2684 if (!gsi_one_before_end_p (gsi
))
2686 ones
= gsi_stmt (gsi
);
2688 gsi
= gsi_start (twoh
);
2689 if (!gsi_one_before_end_p (gsi
))
2691 twos
= gsi_stmt (gsi
);
2693 if (!is_gimple_call (ones
)
2694 || !is_gimple_call (twos
)
2695 || gimple_call_lhs (ones
)
2696 || gimple_call_lhs (twos
)
2697 || gimple_call_chain (ones
)
2698 || gimple_call_chain (twos
)
2699 || !operand_equal_p (gimple_call_fn (ones
), gimple_call_fn (twos
), 0)
2700 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
2703 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
2704 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
2705 gimple_call_arg (twos
, ai
), 0))
2712 try { A() } finally { try { ~B() } catch { ~A() } }
2713 try { ... } finally { ~A() }
2715 try { A() } catch { ~B() }
2716 try { ~B() ... } finally { ~A() }
2718 This occurs frequently in C++, where A is a local variable and B is a
2719 temporary used in the initializer for A. */
2722 optimize_double_finally (gimple one
, gimple two
)
2725 gimple_stmt_iterator gsi
;
2727 gsi
= gsi_start (gimple_try_cleanup (one
));
2728 if (!gsi_one_before_end_p (gsi
))
2731 oneh
= gsi_stmt (gsi
);
2732 if (gimple_code (oneh
) != GIMPLE_TRY
2733 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
2736 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
2738 gimple_seq seq
= gimple_try_eval (oneh
);
2740 gimple_try_set_cleanup (one
, seq
);
2741 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
2742 seq
= copy_gimple_seq_and_replace_locals (seq
);
2743 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
2744 gimple_try_set_eval (two
, seq
);
2748 /* Perform EH refactoring optimizations that are simpler to do when code
2749 flow has been lowered but EH structures haven't. */
2752 refactor_eh_r (gimple_seq seq
)
2754 gimple_stmt_iterator gsi
;
2759 gsi
= gsi_start (seq
);
2763 if (gsi_end_p (gsi
))
2766 two
= gsi_stmt (gsi
);
2769 && gimple_code (one
) == GIMPLE_TRY
2770 && gimple_code (two
) == GIMPLE_TRY
2771 && gimple_try_kind (one
) == GIMPLE_TRY_FINALLY
2772 && gimple_try_kind (two
) == GIMPLE_TRY_FINALLY
)
2773 optimize_double_finally (one
, two
);
2775 switch (gimple_code (one
))
2778 refactor_eh_r (gimple_try_eval (one
));
2779 refactor_eh_r (gimple_try_cleanup (one
));
2782 refactor_eh_r (gimple_catch_handler (one
));
2784 case GIMPLE_EH_FILTER
:
2785 refactor_eh_r (gimple_eh_filter_failure (one
));
2800 refactor_eh_r (gimple_body (current_function_decl
));
2805 gate_refactor_eh (void)
2807 return flag_exceptions
!= 0;
2810 struct gimple_opt_pass pass_refactor_eh
=
2815 gate_refactor_eh
, /* gate */
2816 refactor_eh
, /* execute */
2819 0, /* static_pass_number */
2820 TV_TREE_EH
, /* tv_id */
2821 PROP_gimple_lcf
, /* properties_required */
2822 0, /* properties_provided */
2823 0, /* properties_destroyed */
2824 0, /* todo_flags_start */
2825 TODO_dump_func
/* todo_flags_finish */
2829 /* At the end of gimple optimization, we can lower RESX. */
2832 lower_resx (basic_block bb
, gimple stmt
, struct pointer_map_t
*mnt_map
)
2835 eh_region src_r
, dst_r
;
2836 gimple_stmt_iterator gsi
;
2841 lp_nr
= lookup_stmt_eh_lp (stmt
);
2843 dst_r
= get_eh_region_from_lp_number (lp_nr
);
2847 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
2848 gsi
= gsi_last_bb (bb
);
2852 /* We can wind up with no source region when pass_cleanup_eh shows
2853 that there are no entries into an eh region and deletes it, but
2854 then the block that contains the resx isn't removed. This can
2855 happen without optimization when the switch statement created by
2856 lower_try_finally_switch isn't simplified to remove the eh case.
2858 Resolve this by expanding the resx node to an abort. */
2860 fn
= implicit_built_in_decls
[BUILT_IN_TRAP
];
2861 x
= gimple_build_call (fn
, 0);
2862 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2864 while (EDGE_COUNT (bb
->succs
) > 0)
2865 remove_edge (EDGE_SUCC (bb
, 0));
2869 /* When we have a destination region, we resolve this by copying
2870 the excptr and filter values into place, and changing the edge
2871 to immediately after the landing pad. */
2880 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
2881 the failure decl into a new block, if needed. */
2882 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
2884 slot
= pointer_map_contains (mnt_map
, dst_r
);
2887 gimple_stmt_iterator gsi2
;
2889 new_bb
= create_empty_bb (bb
);
2890 lab
= gimple_block_label (new_bb
);
2891 gsi2
= gsi_start_bb (new_bb
);
2893 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
2894 x
= gimple_build_call (fn
, 0);
2895 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
2896 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
2898 slot
= pointer_map_insert (mnt_map
, dst_r
);
2904 new_bb
= label_to_block (lab
);
2907 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
2908 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
2909 e
->count
= bb
->count
;
2910 e
->probability
= REG_BR_PROB_BASE
;
2915 tree dst_nr
= build_int_cst (NULL
, dst_r
->index
);
2917 fn
= implicit_built_in_decls
[BUILT_IN_EH_COPY_VALUES
];
2918 src_nr
= build_int_cst (NULL
, src_r
->index
);
2919 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
2920 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2922 /* Update the flags for the outgoing edge. */
2923 e
= single_succ_edge (bb
);
2924 gcc_assert (e
->flags
& EDGE_EH
);
2925 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
2927 /* If there are no more EH users of the landing pad, delete it. */
2928 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
2929 if (e
->flags
& EDGE_EH
)
2933 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
2934 remove_eh_landing_pad (lp
);
2944 /* When we don't have a destination region, this exception escapes
2945 up the call chain. We resolve this by generating a call to the
2946 _Unwind_Resume library function. */
2948 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
2949 with no arguments for C++ and Java. Check for that. */
2950 if (src_r
->use_cxa_end_cleanup
)
2952 fn
= implicit_built_in_decls
[BUILT_IN_CXA_END_CLEANUP
];
2953 x
= gimple_build_call (fn
, 0);
2954 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2958 fn
= implicit_built_in_decls
[BUILT_IN_EH_POINTER
];
2959 src_nr
= build_int_cst (NULL
, src_r
->index
);
2960 x
= gimple_build_call (fn
, 1, src_nr
);
2961 var
= create_tmp_var (ptr_type_node
, NULL
);
2962 var
= make_ssa_name (var
, x
);
2963 gimple_call_set_lhs (x
, var
);
2964 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2966 fn
= implicit_built_in_decls
[BUILT_IN_UNWIND_RESUME
];
2967 x
= gimple_build_call (fn
, 1, var
);
2968 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
2971 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
2974 gsi_remove (&gsi
, true);
2980 execute_lower_resx (void)
2983 struct pointer_map_t
*mnt_map
;
2984 bool dominance_invalidated
= false;
2985 bool any_rewritten
= false;
2987 mnt_map
= pointer_map_create ();
2991 gimple last
= last_stmt (bb
);
2992 if (last
&& is_gimple_resx (last
))
2994 dominance_invalidated
|= lower_resx (bb
, last
, mnt_map
);
2995 any_rewritten
= true;
2999 pointer_map_destroy (mnt_map
);
3001 if (dominance_invalidated
)
3003 free_dominance_info (CDI_DOMINATORS
);
3004 free_dominance_info (CDI_POST_DOMINATORS
);
3007 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3011 gate_lower_resx (void)
3013 return flag_exceptions
!= 0;
3016 struct gimple_opt_pass pass_lower_resx
=
3021 gate_lower_resx
, /* gate */
3022 execute_lower_resx
, /* execute */
3025 0, /* static_pass_number */
3026 TV_TREE_EH
, /* tv_id */
3027 PROP_gimple_lcf
, /* properties_required */
3028 0, /* properties_provided */
3029 0, /* properties_destroyed */
3030 0, /* todo_flags_start */
3031 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3036 /* At the end of inlining, we can lower EH_DISPATCH. */
3039 lower_eh_dispatch (basic_block src
, gimple stmt
)
3041 gimple_stmt_iterator gsi
;
3047 region_nr
= gimple_eh_dispatch_region (stmt
);
3048 r
= get_eh_region_from_number (region_nr
);
3050 gsi
= gsi_last_bb (src
);
3056 VEC (tree
, heap
) *labels
= NULL
;
3057 tree default_label
= NULL
;
3062 /* Collect the labels for a switch. Zero the post_landing_pad
3063 field becase we'll no longer have anything keeping these labels
3064 in existance and the optimizer will be free to merge these
3066 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3068 tree tp_node
, flt_node
, lab
= c
->label
;
3071 tp_node
= c
->type_list
;
3072 flt_node
= c
->filter_list
;
3074 if (tp_node
== NULL
)
3076 default_label
= lab
;
3081 tree t
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3082 TREE_VALUE (flt_node
), NULL
, lab
);
3083 VEC_safe_push (tree
, heap
, labels
, t
);
3085 tp_node
= TREE_CHAIN (tp_node
);
3086 flt_node
= TREE_CHAIN (flt_node
);
3091 /* Clean up the edge flags. */
3092 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3094 if (e
->flags
& EDGE_FALLTHRU
)
3096 /* If there was no catch-all, use the fallthru edge. */
3097 if (default_label
== NULL
)
3098 default_label
= gimple_block_label (e
->dest
);
3099 e
->flags
&= ~EDGE_FALLTHRU
;
3102 gcc_assert (default_label
!= NULL
);
3104 /* Don't generate a switch if there's only a default case.
3105 This is common in the form of try { A; } catch (...) { B; }. */
3108 e
= single_succ_edge (src
);
3109 e
->flags
|= EDGE_FALLTHRU
;
3113 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3114 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3115 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3116 filter
= make_ssa_name (filter
, x
);
3117 gimple_call_set_lhs (x
, filter
);
3118 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3120 /* Turn the default label into a default case. */
3121 default_label
= build3 (CASE_LABEL_EXPR
, void_type_node
,
3122 NULL
, NULL
, default_label
);
3123 sort_case_labels (labels
);
3125 x
= gimple_build_switch_vec (filter
, default_label
, labels
);
3126 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3128 VEC_free (tree
, heap
, labels
);
3133 case ERT_ALLOWED_EXCEPTIONS
:
3135 edge b_e
= BRANCH_EDGE (src
);
3136 edge f_e
= FALLTHRU_EDGE (src
);
3138 fn
= implicit_built_in_decls
[BUILT_IN_EH_FILTER
];
3139 x
= gimple_build_call (fn
, 1, build_int_cst (NULL
, region_nr
));
3140 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)), NULL
);
3141 filter
= make_ssa_name (filter
, x
);
3142 gimple_call_set_lhs (x
, filter
);
3143 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3145 r
->u
.allowed
.label
= NULL
;
3146 x
= gimple_build_cond (EQ_EXPR
, filter
,
3147 build_int_cst (TREE_TYPE (filter
),
3148 r
->u
.allowed
.filter
),
3149 NULL_TREE
, NULL_TREE
);
3150 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3152 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3153 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3161 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3162 gsi_remove (&gsi
, true);
3166 execute_lower_eh_dispatch (void)
3169 bool any_rewritten
= false;
3171 assign_filter_values ();
3175 gimple last
= last_stmt (bb
);
3176 if (last
&& gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3178 lower_eh_dispatch (bb
, last
);
3179 any_rewritten
= true;
3183 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3187 gate_lower_eh_dispatch (void)
3189 return cfun
->eh
->region_tree
!= NULL
;
3192 struct gimple_opt_pass pass_lower_eh_dispatch
=
3196 "ehdisp", /* name */
3197 gate_lower_eh_dispatch
, /* gate */
3198 execute_lower_eh_dispatch
, /* execute */
3201 0, /* static_pass_number */
3202 TV_TREE_EH
, /* tv_id */
3203 PROP_gimple_lcf
, /* properties_required */
3204 0, /* properties_provided */
3205 0, /* properties_destroyed */
3206 0, /* todo_flags_start */
3207 TODO_dump_func
| TODO_verify_flow
/* todo_flags_finish */
3211 /* Walk statements, see what regions are really referenced and remove
3212 those that are unused. */
3215 remove_unreachable_handlers (void)
3217 sbitmap r_reachable
, lp_reachable
;
3223 r_reachable
= sbitmap_alloc (VEC_length (eh_region
, cfun
->eh
->region_array
));
3225 = sbitmap_alloc (VEC_length (eh_landing_pad
, cfun
->eh
->lp_array
));
3226 sbitmap_zero (r_reachable
);
3227 sbitmap_zero (lp_reachable
);
3231 gimple_stmt_iterator gsi
= gsi_start_bb (bb
);
3233 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3235 gimple stmt
= gsi_stmt (gsi
);
3236 lp_nr
= lookup_stmt_eh_lp (stmt
);
3238 /* Negative LP numbers are MUST_NOT_THROW regions which
3239 are not considered BB enders. */
3241 SET_BIT (r_reachable
, -lp_nr
);
3243 /* Positive LP numbers are real landing pads, are are BB enders. */
3246 gcc_assert (gsi_one_before_end_p (gsi
));
3247 region
= get_eh_region_from_lp_number (lp_nr
);
3248 SET_BIT (r_reachable
, region
->index
);
3249 SET_BIT (lp_reachable
, lp_nr
);
3256 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3257 dump_eh_tree (dump_file
, cfun
);
3258 fprintf (dump_file
, "Reachable regions: ");
3259 dump_sbitmap_file (dump_file
, r_reachable
);
3260 fprintf (dump_file
, "Reachable landing pads: ");
3261 dump_sbitmap_file (dump_file
, lp_reachable
);
3265 VEC_iterate (eh_region
, cfun
->eh
->region_array
, r_nr
, region
); ++r_nr
)
3266 if (region
&& !TEST_BIT (r_reachable
, r_nr
))
3269 fprintf (dump_file
, "Removing unreachable region %d\n", r_nr
);
3270 remove_eh_handler (region
);
3274 VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, lp_nr
, lp
); ++lp_nr
)
3275 if (lp
&& !TEST_BIT (lp_reachable
, lp_nr
))
3278 fprintf (dump_file
, "Removing unreachable landing pad %d\n", lp_nr
);
3279 remove_eh_landing_pad (lp
);
3284 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3285 dump_eh_tree (dump_file
, cfun
);
3286 fprintf (dump_file
, "\n\n");
3289 sbitmap_free (r_reachable
);
3290 sbitmap_free (lp_reachable
);
3292 #ifdef ENABLE_CHECKING
3293 verify_eh_tree (cfun
);
3297 /* Remove regions that do not have landing pads. This assumes
3298 that remove_unreachable_handlers has already been run, and
3299 that we've just manipulated the landing pads since then. */
3302 remove_unreachable_handlers_no_lp (void)
3307 for (i
= 1; VEC_iterate (eh_region
, cfun
->eh
->region_array
, i
, r
); ++i
)
3308 if (r
&& r
->landing_pads
== NULL
&& r
->type
!= ERT_MUST_NOT_THROW
)
3311 fprintf (dump_file
, "Removing unreachable region %d\n", i
);
3312 remove_eh_handler (r
);
3316 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3317 optimisticaly split all sorts of edges, including EH edges. The
3318 optimization passes in between may not have needed them; if not,
3319 we should undo the split.
3321 Recognize this case by having one EH edge incoming to the BB and
3322 one normal edge outgoing; BB should be empty apart from the
3323 post_landing_pad label.
3325 Note that this is slightly different from the empty handler case
3326 handled by cleanup_empty_eh, in that the actual handler may yet
3327 have actual code but the landing pad has been separated from the
3328 handler. As such, cleanup_empty_eh relies on this transformation
3329 having been done first. */
3332 unsplit_eh (eh_landing_pad lp
)
3334 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3335 gimple_stmt_iterator gsi
;
3338 /* Quickly check the edge counts on BB for singularity. */
3339 if (EDGE_COUNT (bb
->preds
) != 1 || EDGE_COUNT (bb
->succs
) != 1)
3341 e_in
= EDGE_PRED (bb
, 0);
3342 e_out
= EDGE_SUCC (bb
, 0);
3344 /* Input edge must be EH and output edge must be normal. */
3345 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
3348 /* The block must be empty except for the labels. */
3349 if (!gsi_end_p (gsi_after_labels (bb
)))
3352 /* The destination block must not already have a landing pad
3353 for a different region. */
3354 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3356 gimple stmt
= gsi_stmt (gsi
);
3360 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3362 lab
= gimple_label_label (stmt
);
3363 lp_nr
= EH_LANDING_PAD_NR (lab
);
3364 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3368 /* The new destination block must not already be a destination of
3369 the source block, lest we merge fallthru and eh edges and get
3370 all sorts of confused. */
3371 if (find_edge (e_in
->src
, e_out
->dest
))
3374 /* ??? We can get degenerate phis due to cfg cleanups. I would have
3375 thought this should have been cleaned up by a phicprop pass, but
3376 that doesn't appear to handle virtuals. Propagate by hand. */
3377 if (!gimple_seq_empty_p (phi_nodes (bb
)))
3379 for (gsi
= gsi_start_phis (bb
); !gsi_end_p (gsi
); )
3381 gimple use_stmt
, phi
= gsi_stmt (gsi
);
3382 tree lhs
= gimple_phi_result (phi
);
3383 tree rhs
= gimple_phi_arg_def (phi
, 0);
3384 use_operand_p use_p
;
3385 imm_use_iterator iter
;
3387 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
3389 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3390 SET_USE (use_p
, rhs
);
3393 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
3394 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
3396 remove_phi_node (&gsi
, true);
3400 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3401 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
3402 lp
->index
, e_out
->dest
->index
);
3404 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
3405 a successor edge, humor it. But do the real CFG change with the
3406 predecessor of E_OUT in order to preserve the ordering of arguments
3407 to the PHI nodes in E_OUT->DEST. */
3408 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
3409 redirect_edge_pred (e_out
, e_in
->src
);
3410 e_out
->flags
= e_in
->flags
;
3411 e_out
->probability
= e_in
->probability
;
3412 e_out
->count
= e_in
->count
;
3418 /* Examine each landing pad block and see if it matches unsplit_eh. */
3421 unsplit_all_eh (void)
3423 bool changed
= false;
3427 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3429 changed
|= unsplit_eh (lp
);
3434 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
3435 to OLD_BB to NEW_BB; return true on success, false on failure.
3437 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
3438 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
3439 Virtual PHIs may be deleted and marked for renaming. */
3442 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
3443 edge old_bb_out
, bool change_region
)
3445 gimple_stmt_iterator ngsi
, ogsi
;
3448 bitmap rename_virts
;
3449 bitmap ophi_handled
;
3451 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3452 redirect_edge_var_map_clear (e
);
3454 ophi_handled
= BITMAP_ALLOC (NULL
);
3455 rename_virts
= BITMAP_ALLOC (NULL
);
3457 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
3458 for the edges we're going to move. */
3459 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
3461 gimple ophi
, nphi
= gsi_stmt (ngsi
);
3464 nresult
= gimple_phi_result (nphi
);
3465 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
3467 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
3468 the source ssa_name. */
3470 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3472 ophi
= gsi_stmt (ogsi
);
3473 if (gimple_phi_result (ophi
) == nop
)
3478 /* If we did find the corresponding PHI, copy those inputs. */
3481 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
3482 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3487 if ((e
->flags
& EDGE_EH
) == 0)
3489 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
3490 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
3491 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
3494 /* If we didn't find the PHI, but it's a VOP, remember to rename
3495 it later, assuming all other tests succeed. */
3496 else if (!is_gimple_reg (nresult
))
3497 bitmap_set_bit (rename_virts
, SSA_NAME_VERSION (nresult
));
3498 /* If we didn't find the PHI, and it's a real variable, we know
3499 from the fact that OLD_BB is tree_empty_eh_handler_p that the
3500 variable is unchanged from input to the block and we can simply
3501 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
3505 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
3506 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3507 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
3511 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
3512 we don't know what values from the other edges into NEW_BB to use. */
3513 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
3515 gimple ophi
= gsi_stmt (ogsi
);
3516 tree oresult
= gimple_phi_result (ophi
);
3517 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
3521 /* At this point we know that the merge will succeed. Remove the PHI
3522 nodes for the virtuals that we want to rename. */
3523 if (!bitmap_empty_p (rename_virts
))
3525 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); )
3527 gimple nphi
= gsi_stmt (ngsi
);
3528 tree nresult
= gimple_phi_result (nphi
);
3529 if (bitmap_bit_p (rename_virts
, SSA_NAME_VERSION (nresult
)))
3531 mark_virtual_phi_result_for_renaming (nphi
);
3532 remove_phi_node (&ngsi
, true);
3539 /* Finally, move the edges and update the PHIs. */
3540 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
3541 if (e
->flags
& EDGE_EH
)
3543 redirect_eh_edge_1 (e
, new_bb
, change_region
);
3544 redirect_edge_succ (e
, new_bb
);
3545 flush_pending_stmts (e
);
3550 BITMAP_FREE (ophi_handled
);
3551 BITMAP_FREE (rename_virts
);
3555 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
3556 redirect_edge_var_map_clear (e
);
3557 BITMAP_FREE (ophi_handled
);
3558 BITMAP_FREE (rename_virts
);
3562 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
3563 old region to NEW_REGION at BB. */
3566 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
3567 eh_landing_pad lp
, eh_region new_region
)
3569 gimple_stmt_iterator gsi
;
3572 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
3576 lp
->region
= new_region
;
3577 lp
->next_lp
= new_region
->landing_pads
;
3578 new_region
->landing_pads
= lp
;
3580 /* Delete the RESX that was matched within the empty handler block. */
3581 gsi
= gsi_last_bb (bb
);
3582 mark_virtual_ops_for_renaming (gsi_stmt (gsi
));
3583 gsi_remove (&gsi
, true);
3585 /* Clean up E_OUT for the fallthru. */
3586 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3587 e_out
->probability
= REG_BR_PROB_BASE
;
3590 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
3591 unsplitting than unsplit_eh was prepared to handle, e.g. when
3592 multiple incoming edges and phis are involved. */
3595 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
3597 gimple_stmt_iterator gsi
;
3600 /* We really ought not have totally lost everything following
3601 a landing pad label. Given that BB is empty, there had better
3603 gcc_assert (e_out
!= NULL
);
3605 /* The destination block must not already have a landing pad
3606 for a different region. */
3608 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3610 gimple stmt
= gsi_stmt (gsi
);
3613 if (gimple_code (stmt
) != GIMPLE_LABEL
)
3615 lab
= gimple_label_label (stmt
);
3616 lp_nr
= EH_LANDING_PAD_NR (lab
);
3617 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
3621 /* Attempt to move the PHIs into the successor block. */
3622 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
3624 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3626 "Unsplit EH landing pad %d to block %i "
3627 "(via cleanup_empty_eh).\n",
3628 lp
->index
, e_out
->dest
->index
);
3635 /* Examine the block associated with LP to determine if it's an empty
3636 handler for its EH region. If so, attempt to redirect EH edges to
3637 an outer region. Return true the CFG was updated in any way. This
3638 is similar to jump forwarding, just across EH edges. */
3641 cleanup_empty_eh (eh_landing_pad lp
)
3643 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3644 gimple_stmt_iterator gsi
;
3646 eh_region new_region
;
3649 bool has_non_eh_pred
;
3652 /* There can be zero or one edges out of BB. This is the quickest test. */
3653 switch (EDGE_COUNT (bb
->succs
))
3659 e_out
= EDGE_SUCC (bb
, 0);
3664 gsi
= gsi_after_labels (bb
);
3666 /* Make sure to skip debug statements. */
3667 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
3668 gsi_next_nondebug (&gsi
);
3670 /* If the block is totally empty, look for more unsplitting cases. */
3671 if (gsi_end_p (gsi
))
3672 return cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
3674 /* The block should consist only of a single RESX statement. */
3675 resx
= gsi_stmt (gsi
);
3676 if (!is_gimple_resx (resx
))
3678 gcc_assert (gsi_one_before_end_p (gsi
));
3680 /* Determine if there are non-EH edges, or resx edges into the handler. */
3681 has_non_eh_pred
= false;
3682 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3683 if (!(e
->flags
& EDGE_EH
))
3684 has_non_eh_pred
= true;
3686 /* Find the handler that's outer of the empty handler by looking at
3687 where the RESX instruction was vectored. */
3688 new_lp_nr
= lookup_stmt_eh_lp (resx
);
3689 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
3691 /* If there's no destination region within the current function,
3692 redirection is trivial via removing the throwing statements from
3693 the EH region, removing the EH edges, and allowing the block
3694 to go unreachable. */
3695 if (new_region
== NULL
)
3697 gcc_assert (e_out
== NULL
);
3698 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3699 if (e
->flags
& EDGE_EH
)
3701 gimple stmt
= last_stmt (e
->src
);
3702 remove_stmt_from_eh_lp (stmt
);
3710 /* If the destination region is a MUST_NOT_THROW, allow the runtime
3711 to handle the abort and allow the blocks to go unreachable. */
3712 if (new_region
->type
== ERT_MUST_NOT_THROW
)
3714 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
3715 if (e
->flags
& EDGE_EH
)
3717 gimple stmt
= last_stmt (e
->src
);
3718 remove_stmt_from_eh_lp (stmt
);
3719 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
3727 /* Try to redirect the EH edges and merge the PHIs into the destination
3728 landing pad block. If the merge succeeds, we'll already have redirected
3729 all the EH edges. The handler itself will go unreachable if there were
3731 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
3734 /* Finally, if all input edges are EH edges, then we can (potentially)
3735 reduce the number of transfers from the runtime by moving the landing
3736 pad from the original region to the new region. This is a win when
3737 we remove the last CLEANUP region along a particular exception
3738 propagation path. Since nothing changes except for the region with
3739 which the landing pad is associated, the PHI nodes do not need to be
3741 if (!has_non_eh_pred
)
3743 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
3744 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3745 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
3746 lp
->index
, new_region
->index
);
3748 /* ??? The CFG didn't change, but we may have rendered the
3749 old EH region unreachable. Trigger a cleanup there. */
3756 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
3757 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
3758 remove_eh_landing_pad (lp
);
3762 /* Do a post-order traversal of the EH region tree. Examine each
3763 post_landing_pad block and see if we can eliminate it as empty. */
3766 cleanup_all_empty_eh (void)
3768 bool changed
= false;
3772 for (i
= 1; VEC_iterate (eh_landing_pad
, cfun
->eh
->lp_array
, i
, lp
); ++i
)
3774 changed
|= cleanup_empty_eh (lp
);
3779 /* Perform cleanups and lowering of exception handling
3780 1) cleanups regions with handlers doing nothing are optimized out
3781 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
3782 3) Info about regions that are containing instructions, and regions
3783 reachable via local EH edges is collected
3784 4) Eh tree is pruned for regions no longer neccesary.
3786 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
3787 Unify those that have the same failure decl and locus.
3791 execute_cleanup_eh (void)
3793 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
3794 looking up unreachable landing pads. */
3795 remove_unreachable_handlers ();
3797 /* Watch out for the region tree vanishing due to all unreachable. */
3798 if (cfun
->eh
->region_tree
&& optimize
)
3800 bool changed
= false;
3802 changed
|= unsplit_all_eh ();
3803 changed
|= cleanup_all_empty_eh ();
3807 free_dominance_info (CDI_DOMINATORS
);
3808 free_dominance_info (CDI_POST_DOMINATORS
);
3810 /* We delayed all basic block deletion, as we may have performed
3811 cleanups on EH edges while non-EH edges were still present. */
3812 delete_unreachable_blocks ();
3814 /* We manipulated the landing pads. Remove any region that no
3815 longer has a landing pad. */
3816 remove_unreachable_handlers_no_lp ();
3818 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
3826 gate_cleanup_eh (void)
3828 return cfun
->eh
!= NULL
&& cfun
->eh
->region_tree
!= NULL
;
3831 struct gimple_opt_pass pass_cleanup_eh
= {
3834 "ehcleanup", /* name */
3835 gate_cleanup_eh
, /* gate */
3836 execute_cleanup_eh
, /* execute */
3839 0, /* static_pass_number */
3840 TV_TREE_EH
, /* tv_id */
3841 PROP_gimple_lcf
, /* properties_required */
3842 0, /* properties_provided */
3843 0, /* properties_destroyed */
3844 0, /* todo_flags_start */
3845 TODO_dump_func
/* todo_flags_finish */
3849 /* Verify that BB containing STMT as the last statement, has precisely the
3850 edge that make_eh_edges would create. */
3853 verify_eh_edges (gimple stmt
)
3855 basic_block bb
= gimple_bb (stmt
);
3856 eh_landing_pad lp
= NULL
;
3861 lp_nr
= lookup_stmt_eh_lp (stmt
);
3863 lp
= get_eh_landing_pad_from_number (lp_nr
);
3866 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
3868 if (e
->flags
& EDGE_EH
)
3872 error ("BB %i has multiple EH edges", bb
->index
);
3884 error ("BB %i can not throw but has an EH edge", bb
->index
);
3890 if (!stmt_could_throw_p (stmt
))
3892 error ("BB %i last statement has incorrectly set lp", bb
->index
);
3896 if (eh_edge
== NULL
)
3898 error ("BB %i is missing an EH edge", bb
->index
);
3902 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
3904 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
3911 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
3914 verify_eh_dispatch_edge (gimple stmt
)
3918 basic_block src
, dst
;
3919 bool want_fallthru
= true;
3923 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
3924 src
= gimple_bb (stmt
);
3926 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3927 gcc_assert (e
->aux
== NULL
);
3932 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3934 dst
= label_to_block (c
->label
);
3935 e
= find_edge (src
, dst
);
3938 error ("BB %i is missing an edge", src
->index
);
3943 /* A catch-all handler doesn't have a fallthru. */
3944 if (c
->type_list
== NULL
)
3946 want_fallthru
= false;
3952 case ERT_ALLOWED_EXCEPTIONS
:
3953 dst
= label_to_block (r
->u
.allowed
.label
);
3954 e
= find_edge (src
, dst
);
3957 error ("BB %i is missing an edge", src
->index
);
3968 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3970 if (e
->flags
& EDGE_FALLTHRU
)
3972 if (fall_edge
!= NULL
)
3974 error ("BB %i too many fallthru edges", src
->index
);
3983 error ("BB %i has incorrect edge", src
->index
);
3987 if ((fall_edge
!= NULL
) ^ want_fallthru
)
3989 error ("BB %i has incorrect fallthru edge", src
->index
);