1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2015 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
23 #include "hash-table.h"
28 #include "double-int.h"
35 #include "fold-const.h"
39 #include "hard-reg-set.h"
44 #include "dominance.h"
47 #include "cfgcleanup.h"
48 #include "basic-block.h"
49 #include "tree-ssa-alias.h"
50 #include "internal-fn.h"
52 #include "gimple-expr.h"
55 #include "gimple-iterator.h"
56 #include "gimple-ssa.h"
58 #include "plugin-api.h"
62 #include "tree-phinodes.h"
63 #include "ssa-iterators.h"
64 #include "stringpool.h"
65 #include "tree-ssanames.h"
66 #include "tree-into-ssa.h"
68 #include "tree-inline.h"
69 #include "tree-pass.h"
70 #include "langhooks.h"
71 #include "diagnostic-core.h"
74 #include "gimple-low.h"
76 /* In some instances a tree and a gimple need to be stored in a same table,
77 i.e. in hash tables. This is a structure to do this. */
78 typedef union {tree
*tp
; tree t
; gimple g
;} treemple
;
80 /* Misc functions used in this file. */
82 /* Remember and lookup EH landing pad data for arbitrary statements.
83 Really this means any statement that could_throw_p. We could
84 stuff this information into the stmt_ann data structure, but:
86 (1) We absolutely rely on this information being kept until
87 we get to rtl. Once we're done with lowering here, if we lose
88 the information there's no way to recover it!
90 (2) There are many more statements that *cannot* throw as
91 compared to those that can. We should be saving some amount
92 of space by only allocating memory for those that can throw. */
94 /* Add statement T in function IFUN to landing pad NUM. */
97 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple t
, int num
)
99 gcc_assert (num
!= 0);
101 if (!get_eh_throw_stmt_table (ifun
))
102 set_eh_throw_stmt_table (ifun
, hash_map
<gimple
, int>::create_ggc (31));
104 gcc_assert (!get_eh_throw_stmt_table (ifun
)->put (t
, num
));
107 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
110 add_stmt_to_eh_lp (gimple t
, int num
)
112 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
115 /* Add statement T to the single EH landing pad in REGION. */
118 record_stmt_eh_region (eh_region region
, gimple t
)
122 if (region
->type
== ERT_MUST_NOT_THROW
)
123 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
126 eh_landing_pad lp
= region
->landing_pads
;
128 lp
= gen_eh_landing_pad (region
);
130 gcc_assert (lp
->next_lp
== NULL
);
131 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
136 /* Remove statement T in function IFUN from its EH landing pad. */
139 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple t
)
141 if (!get_eh_throw_stmt_table (ifun
))
144 if (!get_eh_throw_stmt_table (ifun
)->get (t
))
147 get_eh_throw_stmt_table (ifun
)->remove (t
);
152 /* Remove statement T in the current function (cfun) from its
156 remove_stmt_from_eh_lp (gimple t
)
158 return remove_stmt_from_eh_lp_fn (cfun
, t
);
161 /* Determine if statement T is inside an EH region in function IFUN.
162 Positive numbers indicate a landing pad index; negative numbers
163 indicate a MUST_NOT_THROW region index; zero indicates that the
164 statement is not recorded in the region table. */
167 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple t
)
169 if (ifun
->eh
->throw_stmt_table
== NULL
)
172 int *lp_nr
= ifun
->eh
->throw_stmt_table
->get (t
);
173 return lp_nr
? *lp_nr
: 0;
176 /* Likewise, but always use the current function. */
179 lookup_stmt_eh_lp (gimple t
)
181 /* We can get called from initialized data when -fnon-call-exceptions
182 is on; prevent crash. */
185 return lookup_stmt_eh_lp_fn (cfun
, t
);
188 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
189 nodes and LABEL_DECL nodes. We will use this during the second phase to
190 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
192 struct finally_tree_node
194 /* When storing a GIMPLE_TRY, we have to record a gimple. However
195 when deciding whether a GOTO to a certain LABEL_DECL (which is a
196 tree) leaves the TRY block, its necessary to record a tree in
197 this field. Thus a treemple is used. */
202 /* Hashtable helpers. */
204 struct finally_tree_hasher
: typed_free_remove
<finally_tree_node
>
206 typedef finally_tree_node value_type
;
207 typedef finally_tree_node compare_type
;
208 static inline hashval_t
hash (const value_type
*);
209 static inline bool equal (const value_type
*, const compare_type
*);
213 finally_tree_hasher::hash (const value_type
*v
)
215 return (intptr_t)v
->child
.t
>> 4;
219 finally_tree_hasher::equal (const value_type
*v
, const compare_type
*c
)
221 return v
->child
.t
== c
->child
.t
;
224 /* Note that this table is *not* marked GTY. It is short-lived. */
225 static hash_table
<finally_tree_hasher
> *finally_tree
;
228 record_in_finally_tree (treemple child
, gtry
*parent
)
230 struct finally_tree_node
*n
;
231 finally_tree_node
**slot
;
233 n
= XNEW (struct finally_tree_node
);
237 slot
= finally_tree
->find_slot (n
, INSERT
);
243 collect_finally_tree (gimple stmt
, gtry
*region
);
245 /* Go through the gimple sequence. Works with collect_finally_tree to
246 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
249 collect_finally_tree_1 (gimple_seq seq
, gtry
*region
)
251 gimple_stmt_iterator gsi
;
253 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
254 collect_finally_tree (gsi_stmt (gsi
), region
);
258 collect_finally_tree (gimple stmt
, gtry
*region
)
262 switch (gimple_code (stmt
))
265 temp
.t
= gimple_label_label (as_a
<glabel
*> (stmt
));
266 record_in_finally_tree (temp
, region
);
270 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
273 record_in_finally_tree (temp
, region
);
274 collect_finally_tree_1 (gimple_try_eval (stmt
),
275 as_a
<gtry
*> (stmt
));
276 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
278 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
280 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
281 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
286 collect_finally_tree_1 (gimple_catch_handler (
287 as_a
<gcatch
*> (stmt
)),
291 case GIMPLE_EH_FILTER
:
292 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
297 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
298 collect_finally_tree_1 (gimple_eh_else_n_body (eh_else_stmt
), region
);
299 collect_finally_tree_1 (gimple_eh_else_e_body (eh_else_stmt
), region
);
304 /* A type, a decl, or some kind of statement that we're not
305 interested in. Don't walk them. */
311 /* Use the finally tree to determine if a jump from START to TARGET
312 would leave the try_finally node that START lives in. */
315 outside_finally_tree (treemple start
, gimple target
)
317 struct finally_tree_node n
, *p
;
322 p
= finally_tree
->find (&n
);
327 while (start
.g
!= target
);
332 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
333 nodes into a set of gotos, magic labels, and eh regions.
334 The eh region creation is straight-forward, but frobbing all the gotos
335 and such into shape isn't. */
337 /* The sequence into which we record all EH stuff. This will be
338 placed at the end of the function when we're all done. */
339 static gimple_seq eh_seq
;
341 /* Record whether an EH region contains something that can throw,
342 indexed by EH region number. */
343 static bitmap eh_region_may_contain_throw_map
;
345 /* The GOTO_QUEUE is is an array of GIMPLE_GOTO and GIMPLE_RETURN
346 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
347 The idea is to record a gimple statement for everything except for
348 the conditionals, which get their labels recorded. Since labels are
349 of type 'tree', we need this node to store both gimple and tree
350 objects. REPL_STMT is the sequence used to replace the goto/return
351 statement. CONT_STMT is used to store the statement that allows
352 the return/goto to jump to the original destination. */
354 struct goto_queue_node
358 gimple_seq repl_stmt
;
361 /* This is used when index >= 0 to indicate that stmt is a label (as
362 opposed to a goto stmt). */
366 /* State of the world while lowering. */
370 /* What's "current" while constructing the eh region tree. These
371 correspond to variables of the same name in cfun->eh, which we
372 don't have easy access to. */
373 eh_region cur_region
;
375 /* What's "current" for the purposes of __builtin_eh_pointer. For
376 a CATCH, this is the associated TRY. For an EH_FILTER, this is
377 the associated ALLOWED_EXCEPTIONS, etc. */
378 eh_region ehp_region
;
380 /* Processing of TRY_FINALLY requires a bit more state. This is
381 split out into a separate structure so that we don't have to
382 copy so much when processing other nodes. */
383 struct leh_tf_state
*tf
;
388 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
389 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
390 this so that outside_finally_tree can reliably reference the tree used
391 in the collect_finally_tree data structures. */
392 gtry
*try_finally_expr
;
395 /* While lowering a top_p usually it is expanded into multiple statements,
396 thus we need the following field to store them. */
397 gimple_seq top_p_seq
;
399 /* The state outside this try_finally node. */
400 struct leh_state
*outer
;
402 /* The exception region created for it. */
405 /* The goto queue. */
406 struct goto_queue_node
*goto_queue
;
407 size_t goto_queue_size
;
408 size_t goto_queue_active
;
410 /* Pointer map to help in searching goto_queue when it is large. */
411 hash_map
<gimple
, goto_queue_node
*> *goto_queue_map
;
413 /* The set of unique labels seen as entries in the goto queue. */
414 vec
<tree
> dest_array
;
416 /* A label to be added at the end of the completed transformed
417 sequence. It will be set if may_fallthru was true *at one time*,
418 though subsequent transformations may have cleared that flag. */
421 /* True if it is possible to fall out the bottom of the try block.
422 Cleared if the fallthru is converted to a goto. */
425 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
428 /* True if the finally block can receive an exception edge.
429 Cleared if the exception case is handled by code duplication. */
433 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gtry
*);
435 /* Search for STMT in the goto queue. Return the replacement,
436 or null if the statement isn't in the queue. */
438 #define LARGE_GOTO_QUEUE 20
440 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
443 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
447 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
449 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
450 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
451 return tf
->goto_queue
[i
].repl_stmt
;
455 /* If we have a large number of entries in the goto_queue, create a
456 pointer map and use that for searching. */
458 if (!tf
->goto_queue_map
)
460 tf
->goto_queue_map
= new hash_map
<gimple
, goto_queue_node
*>;
461 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
463 bool existed
= tf
->goto_queue_map
->put (tf
->goto_queue
[i
].stmt
.g
,
465 gcc_assert (!existed
);
469 goto_queue_node
**slot
= tf
->goto_queue_map
->get (stmt
.g
);
471 return ((*slot
)->repl_stmt
);
476 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
477 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
478 then we can just splat it in, otherwise we add the new stmts immediately
479 after the GIMPLE_COND and redirect. */
482 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
483 gimple_stmt_iterator
*gsi
)
488 location_t loc
= gimple_location (gsi_stmt (*gsi
));
491 new_seq
= find_goto_replacement (tf
, temp
);
495 if (gimple_seq_singleton_p (new_seq
)
496 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
498 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
502 label
= create_artificial_label (loc
);
503 /* Set the new label for the GIMPLE_COND */
506 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
507 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
510 /* The real work of replace_goto_queue. Returns with TSI updated to
511 point to the next statement. */
513 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
516 replace_goto_queue_1 (gimple stmt
, struct leh_tf_state
*tf
,
517 gimple_stmt_iterator
*gsi
)
523 switch (gimple_code (stmt
))
528 seq
= find_goto_replacement (tf
, temp
);
531 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
532 gsi_remove (gsi
, false);
538 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
539 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
543 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
544 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
547 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (
548 as_a
<gcatch
*> (stmt
)),
551 case GIMPLE_EH_FILTER
:
552 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
556 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
557 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (eh_else_stmt
),
559 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (eh_else_stmt
),
565 /* These won't have gotos in them. */
572 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
575 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
577 gimple_stmt_iterator gsi
= gsi_start (*seq
);
579 while (!gsi_end_p (gsi
))
580 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
583 /* Replace all goto queue members. */
586 replace_goto_queue (struct leh_tf_state
*tf
)
588 if (tf
->goto_queue_active
== 0)
590 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
591 replace_goto_queue_stmt_list (&eh_seq
, tf
);
594 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
595 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
599 record_in_goto_queue (struct leh_tf_state
*tf
,
606 struct goto_queue_node
*q
;
608 gcc_assert (!tf
->goto_queue_map
);
610 active
= tf
->goto_queue_active
;
611 size
= tf
->goto_queue_size
;
614 size
= (size
? size
* 2 : 32);
615 tf
->goto_queue_size
= size
;
617 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
620 q
= &tf
->goto_queue
[active
];
621 tf
->goto_queue_active
= active
+ 1;
623 memset (q
, 0, sizeof (*q
));
626 q
->location
= location
;
627 q
->is_label
= is_label
;
630 /* Record the LABEL label in the goto queue contained in TF.
634 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
638 treemple temp
, new_stmt
;
643 /* Computed and non-local gotos do not get processed. Given
644 their nature we can neither tell whether we've escaped the
645 finally block nor redirect them if we knew. */
646 if (TREE_CODE (label
) != LABEL_DECL
)
649 /* No need to record gotos that don't leave the try block. */
651 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
654 if (! tf
->dest_array
.exists ())
656 tf
->dest_array
.create (10);
657 tf
->dest_array
.quick_push (label
);
662 int n
= tf
->dest_array
.length ();
663 for (index
= 0; index
< n
; ++index
)
664 if (tf
->dest_array
[index
] == label
)
667 tf
->dest_array
.safe_push (label
);
670 /* In the case of a GOTO we want to record the destination label,
671 since with a GIMPLE_COND we have an easy access to the then/else
674 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
677 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
678 node, and if so record that fact in the goto queue associated with that
682 maybe_record_in_goto_queue (struct leh_state
*state
, gimple stmt
)
684 struct leh_tf_state
*tf
= state
->tf
;
690 switch (gimple_code (stmt
))
694 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
695 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 2);
696 record_in_goto_queue_label (tf
, new_stmt
,
697 gimple_cond_true_label (cond_stmt
),
698 EXPR_LOCATION (*new_stmt
.tp
));
699 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 3);
700 record_in_goto_queue_label (tf
, new_stmt
,
701 gimple_cond_false_label (cond_stmt
),
702 EXPR_LOCATION (*new_stmt
.tp
));
707 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
708 gimple_location (stmt
));
712 tf
->may_return
= true;
714 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
723 #ifdef ENABLE_CHECKING
724 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
725 was in fact structured, and we've not yet done jump threading, then none
726 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
729 verify_norecord_switch_expr (struct leh_state
*state
,
730 gswitch
*switch_expr
)
732 struct leh_tf_state
*tf
= state
->tf
;
738 n
= gimple_switch_num_labels (switch_expr
);
740 for (i
= 0; i
< n
; ++i
)
743 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
745 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
749 #define verify_norecord_switch_expr(state, switch_expr)
752 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
753 non-null, insert it before the new branch. */
756 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
760 /* In the case of a return, the queue node must be a gimple statement. */
761 gcc_assert (!q
->is_label
);
763 /* Note that the return value may have already been computed, e.g.,
776 should return 0, not 1. We don't have to do anything to make
777 this happens because the return value has been placed in the
778 RESULT_DECL already. */
780 q
->cont_stmt
= q
->stmt
.g
;
783 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
785 x
= gimple_build_goto (finlab
);
786 gimple_set_location (x
, q
->location
);
787 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
790 /* Similar, but easier, for GIMPLE_GOTO. */
793 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
794 struct leh_tf_state
*tf
)
798 gcc_assert (q
->is_label
);
800 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
803 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
805 x
= gimple_build_goto (finlab
);
806 gimple_set_location (x
, q
->location
);
807 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
810 /* Emit a standard landing pad sequence into SEQ for REGION. */
813 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
815 eh_landing_pad lp
= region
->landing_pads
;
819 lp
= gen_eh_landing_pad (region
);
821 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
822 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
824 x
= gimple_build_label (lp
->post_landing_pad
);
825 gimple_seq_add_stmt (seq
, x
);
828 /* Emit a RESX statement into SEQ for REGION. */
831 emit_resx (gimple_seq
*seq
, eh_region region
)
833 gresx
*x
= gimple_build_resx (region
->index
);
834 gimple_seq_add_stmt (seq
, x
);
836 record_stmt_eh_region (region
->outer
, x
);
839 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
842 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
844 geh_dispatch
*x
= gimple_build_eh_dispatch (region
->index
);
845 gimple_seq_add_stmt (seq
, x
);
848 /* Note that the current EH region may contain a throw, or a
849 call to a function which itself may contain a throw. */
852 note_eh_region_may_contain_throw (eh_region region
)
854 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
856 if (region
->type
== ERT_MUST_NOT_THROW
)
858 region
= region
->outer
;
864 /* Check if REGION has been marked as containing a throw. If REGION is
865 NULL, this predicate is false. */
868 eh_region_may_contain_throw (eh_region r
)
870 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
873 /* We want to transform
874 try { body; } catch { stuff; }
884 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
885 should be placed before the second operand, or NULL. OVER is
886 an existing label that should be put at the exit, or NULL. */
889 frob_into_branch_around (gtry
*tp
, eh_region region
, tree over
)
892 gimple_seq cleanup
, result
;
893 location_t loc
= gimple_location (tp
);
895 cleanup
= gimple_try_cleanup (tp
);
896 result
= gimple_try_eval (tp
);
899 emit_post_landing_pad (&eh_seq
, region
);
901 if (gimple_seq_may_fallthru (cleanup
))
904 over
= create_artificial_label (loc
);
905 x
= gimple_build_goto (over
);
906 gimple_set_location (x
, loc
);
907 gimple_seq_add_stmt (&cleanup
, x
);
909 gimple_seq_add_seq (&eh_seq
, cleanup
);
913 x
= gimple_build_label (over
);
914 gimple_seq_add_stmt (&result
, x
);
919 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
920 Make sure to record all new labels found. */
923 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
928 gimple_stmt_iterator gsi
;
930 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
932 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
934 gimple stmt
= gsi_stmt (gsi
);
935 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
937 tree block
= gimple_block (stmt
);
938 gimple_set_location (stmt
, loc
);
939 gimple_set_block (stmt
, block
);
944 region
= outer_state
->tf
->try_finally_expr
;
945 collect_finally_tree_1 (new_seq
, region
);
950 /* A subroutine of lower_try_finally. Create a fallthru label for
951 the given try_finally state. The only tricky bit here is that
952 we have to make sure to record the label in our outer context. */
955 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
957 tree label
= tf
->fallthru_label
;
962 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
963 tf
->fallthru_label
= label
;
967 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
973 /* A subroutine of lower_try_finally. If FINALLY consits of a
974 GIMPLE_EH_ELSE node, return it. */
976 static inline geh_else
*
977 get_eh_else (gimple_seq finally
)
979 gimple x
= gimple_seq_first_stmt (finally
);
980 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
982 gcc_assert (gimple_seq_singleton_p (finally
));
983 return as_a
<geh_else
*> (x
);
988 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
989 langhook returns non-null, then the language requires that the exception
990 path out of a try_finally be treated specially. To wit: the code within
991 the finally block may not itself throw an exception. We have two choices
992 here. First we can duplicate the finally block and wrap it in a
993 must_not_throw region. Second, we can generate code like
998 if (fintmp == eh_edge)
999 protect_cleanup_actions;
1002 where "fintmp" is the temporary used in the switch statement generation
1003 alternative considered below. For the nonce, we always choose the first
1006 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
1009 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
1010 struct leh_state
*this_state
,
1011 struct leh_tf_state
*tf
)
1013 tree protect_cleanup_actions
;
1014 gimple_stmt_iterator gsi
;
1015 bool finally_may_fallthru
;
1022 /* First check for nothing to do. */
1023 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1025 protect_cleanup_actions
= lang_hooks
.eh_protect_cleanup_actions ();
1026 if (protect_cleanup_actions
== NULL
)
1029 finally
= gimple_try_cleanup (tf
->top_p
);
1030 eh_else
= get_eh_else (finally
);
1032 /* Duplicate the FINALLY block. Only need to do this for try-finally,
1033 and not for cleanups. If we've got an EH_ELSE, extract it now. */
1036 finally
= gimple_eh_else_e_body (eh_else
);
1037 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
1039 else if (this_state
)
1040 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1041 gimple_location (tf
->try_finally_expr
));
1042 finally_may_fallthru
= gimple_seq_may_fallthru (finally
);
1044 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1045 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1046 to be in an enclosing scope, but needs to be implemented at this level
1047 to avoid a nesting violation (see wrap_temporary_cleanups in
1048 cp/decl.c). Since it's logically at an outer level, we should call
1049 terminate before we get to it, so strip it away before adding the
1050 MUST_NOT_THROW filter. */
1051 gsi
= gsi_start (finally
);
1053 if (gimple_code (x
) == GIMPLE_TRY
1054 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1055 && gimple_try_catch_is_cleanup (x
))
1057 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1058 gsi_remove (&gsi
, false);
1061 /* Wrap the block with protect_cleanup_actions as the action. */
1062 eh_mnt
= gimple_build_eh_must_not_throw (protect_cleanup_actions
);
1063 try_stmt
= gimple_build_try (finally
, gimple_seq_alloc_with_stmt (eh_mnt
),
1065 finally
= lower_eh_must_not_throw (outer_state
, try_stmt
);
1067 /* Drop all of this into the exception sequence. */
1068 emit_post_landing_pad (&eh_seq
, tf
->region
);
1069 gimple_seq_add_seq (&eh_seq
, finally
);
1070 if (finally_may_fallthru
)
1071 emit_resx (&eh_seq
, tf
->region
);
1073 /* Having now been handled, EH isn't to be considered with
1074 the rest of the outgoing edges. */
1075 tf
->may_throw
= false;
1078 /* A subroutine of lower_try_finally. We have determined that there is
1079 no fallthru edge out of the finally block. This means that there is
1080 no outgoing edge corresponding to any incoming edge. Restructure the
1081 try_finally node for this special case. */
1084 lower_try_finally_nofallthru (struct leh_state
*state
,
1085 struct leh_tf_state
*tf
)
1091 struct goto_queue_node
*q
, *qe
;
1093 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1095 /* We expect that tf->top_p is a GIMPLE_TRY. */
1096 finally
= gimple_try_cleanup (tf
->top_p
);
1097 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1099 x
= gimple_build_label (lab
);
1100 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1103 qe
= q
+ tf
->goto_queue_active
;
1106 do_return_redirection (q
, lab
, NULL
);
1108 do_goto_redirection (q
, lab
, NULL
, tf
);
1110 replace_goto_queue (tf
);
1112 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1113 eh_else
= get_eh_else (finally
);
1116 finally
= gimple_eh_else_n_body (eh_else
);
1117 lower_eh_constructs_1 (state
, &finally
);
1118 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1122 finally
= gimple_eh_else_e_body (eh_else
);
1123 lower_eh_constructs_1 (state
, &finally
);
1125 emit_post_landing_pad (&eh_seq
, tf
->region
);
1126 gimple_seq_add_seq (&eh_seq
, finally
);
1131 lower_eh_constructs_1 (state
, &finally
);
1132 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1136 emit_post_landing_pad (&eh_seq
, tf
->region
);
1138 x
= gimple_build_goto (lab
);
1139 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1140 gimple_seq_add_stmt (&eh_seq
, x
);
1145 /* A subroutine of lower_try_finally. We have determined that there is
1146 exactly one destination of the finally block. Restructure the
1147 try_finally node for this special case. */
1150 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1152 struct goto_queue_node
*q
, *qe
;
1157 gimple_stmt_iterator gsi
;
1159 location_t loc
= gimple_location (tf
->try_finally_expr
);
1161 finally
= gimple_try_cleanup (tf
->top_p
);
1162 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1164 /* Since there's only one destination, and the destination edge can only
1165 either be EH or non-EH, that implies that all of our incoming edges
1166 are of the same type. Therefore we can lower EH_ELSE immediately. */
1167 eh_else
= get_eh_else (finally
);
1171 finally
= gimple_eh_else_e_body (eh_else
);
1173 finally
= gimple_eh_else_n_body (eh_else
);
1176 lower_eh_constructs_1 (state
, &finally
);
1178 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1180 gimple stmt
= gsi_stmt (gsi
);
1181 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1183 tree block
= gimple_block (stmt
);
1184 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1185 gimple_set_block (stmt
, block
);
1191 /* Only reachable via the exception edge. Add the given label to
1192 the head of the FINALLY block. Append a RESX at the end. */
1193 emit_post_landing_pad (&eh_seq
, tf
->region
);
1194 gimple_seq_add_seq (&eh_seq
, finally
);
1195 emit_resx (&eh_seq
, tf
->region
);
1199 if (tf
->may_fallthru
)
1201 /* Only reachable via the fallthru edge. Do nothing but let
1202 the two blocks run together; we'll fall out the bottom. */
1203 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1207 finally_label
= create_artificial_label (loc
);
1208 label_stmt
= gimple_build_label (finally_label
);
1209 gimple_seq_add_stmt (&tf
->top_p_seq
, label_stmt
);
1211 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1214 qe
= q
+ tf
->goto_queue_active
;
1218 /* Reachable by return expressions only. Redirect them. */
1220 do_return_redirection (q
, finally_label
, NULL
);
1221 replace_goto_queue (tf
);
1225 /* Reachable by goto expressions only. Redirect them. */
1227 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1228 replace_goto_queue (tf
);
1230 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1232 /* Reachable by goto to fallthru label only. Redirect it
1233 to the new label (already created, sadly), and do not
1234 emit the final branch out, or the fallthru label. */
1235 tf
->fallthru_label
= NULL
;
1240 /* Place the original return/goto to the original destination
1241 immediately after the finally block. */
1242 x
= tf
->goto_queue
[0].cont_stmt
;
1243 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1244 maybe_record_in_goto_queue (state
, x
);
1247 /* A subroutine of lower_try_finally. There are multiple edges incoming
1248 and outgoing from the finally block. Implement this by duplicating the
1249 finally block for every destination. */
1252 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1255 gimple_seq new_stmt
;
1260 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1262 finally
= gimple_try_cleanup (tf
->top_p
);
1264 /* Notice EH_ELSE, and simplify some of the remaining code
1265 by considering FINALLY to be the normal return path only. */
1266 eh_else
= get_eh_else (finally
);
1268 finally
= gimple_eh_else_n_body (eh_else
);
1270 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1273 if (tf
->may_fallthru
)
1275 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1276 lower_eh_constructs_1 (state
, &seq
);
1277 gimple_seq_add_seq (&new_stmt
, seq
);
1279 tmp
= lower_try_finally_fallthru_label (tf
);
1280 x
= gimple_build_goto (tmp
);
1281 gimple_set_location (x
, tf_loc
);
1282 gimple_seq_add_stmt (&new_stmt
, x
);
1287 /* We don't need to copy the EH path of EH_ELSE,
1288 since it is only emitted once. */
1290 seq
= gimple_eh_else_e_body (eh_else
);
1292 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1293 lower_eh_constructs_1 (state
, &seq
);
1295 emit_post_landing_pad (&eh_seq
, tf
->region
);
1296 gimple_seq_add_seq (&eh_seq
, seq
);
1297 emit_resx (&eh_seq
, tf
->region
);
1302 struct goto_queue_node
*q
, *qe
;
1303 int return_index
, index
;
1306 struct goto_queue_node
*q
;
1310 return_index
= tf
->dest_array
.length ();
1311 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1314 qe
= q
+ tf
->goto_queue_active
;
1317 index
= q
->index
< 0 ? return_index
: q
->index
;
1319 if (!labels
[index
].q
)
1320 labels
[index
].q
= q
;
1323 for (index
= 0; index
< return_index
+ 1; index
++)
1327 q
= labels
[index
].q
;
1331 lab
= labels
[index
].label
1332 = create_artificial_label (tf_loc
);
1334 if (index
== return_index
)
1335 do_return_redirection (q
, lab
, NULL
);
1337 do_goto_redirection (q
, lab
, NULL
, tf
);
1339 x
= gimple_build_label (lab
);
1340 gimple_seq_add_stmt (&new_stmt
, x
);
1342 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1343 lower_eh_constructs_1 (state
, &seq
);
1344 gimple_seq_add_seq (&new_stmt
, seq
);
1346 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1347 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1350 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1354 index
= q
->index
< 0 ? return_index
: q
->index
;
1356 if (labels
[index
].q
== q
)
1359 lab
= labels
[index
].label
;
1361 if (index
== return_index
)
1362 do_return_redirection (q
, lab
, NULL
);
1364 do_goto_redirection (q
, lab
, NULL
, tf
);
1367 replace_goto_queue (tf
);
1371 /* Need to link new stmts after running replace_goto_queue due
1372 to not wanting to process the same goto stmts twice. */
1373 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1376 /* A subroutine of lower_try_finally. There are multiple edges incoming
1377 and outgoing from the finally block. Implement this by instrumenting
1378 each incoming edge and creating a switch statement at the end of the
1379 finally block that branches to the appropriate destination. */
1382 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1384 struct goto_queue_node
*q
, *qe
;
1385 tree finally_tmp
, finally_label
;
1386 int return_index
, eh_index
, fallthru_index
;
1387 int nlabels
, ndests
, j
, last_case_index
;
1389 vec
<tree
> case_label_vec
;
1390 gimple_seq switch_body
= NULL
;
1396 hash_map
<tree
, gimple
> *cont_map
= NULL
;
1397 /* The location of the TRY_FINALLY stmt. */
1398 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1399 /* The location of the finally block. */
1400 location_t finally_loc
;
1402 finally
= gimple_try_cleanup (tf
->top_p
);
1403 eh_else
= get_eh_else (finally
);
1405 /* Mash the TRY block to the head of the chain. */
1406 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1408 /* The location of the finally is either the last stmt in the finally
1409 block or the location of the TRY_FINALLY itself. */
1410 x
= gimple_seq_last_stmt (finally
);
1411 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1413 /* Prepare for switch statement generation. */
1414 nlabels
= tf
->dest_array
.length ();
1415 return_index
= nlabels
;
1416 eh_index
= return_index
+ tf
->may_return
;
1417 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1418 ndests
= fallthru_index
+ tf
->may_fallthru
;
1420 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1421 finally_label
= create_artificial_label (finally_loc
);
1423 /* We use vec::quick_push on case_label_vec throughout this function,
1424 since we know the size in advance and allocate precisely as muce
1426 case_label_vec
.create (ndests
);
1428 last_case_index
= 0;
1430 /* Begin inserting code for getting to the finally block. Things
1431 are done in this order to correspond to the sequence the code is
1434 if (tf
->may_fallthru
)
1436 x
= gimple_build_assign (finally_tmp
,
1437 build_int_cst (integer_type_node
,
1439 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1441 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1442 last_case
= build_case_label (tmp
, NULL
,
1443 create_artificial_label (tf_loc
));
1444 case_label_vec
.quick_push (last_case
);
1447 x
= gimple_build_label (CASE_LABEL (last_case
));
1448 gimple_seq_add_stmt (&switch_body
, x
);
1450 tmp
= lower_try_finally_fallthru_label (tf
);
1451 x
= gimple_build_goto (tmp
);
1452 gimple_set_location (x
, tf_loc
);
1453 gimple_seq_add_stmt (&switch_body
, x
);
1456 /* For EH_ELSE, emit the exception path (plus resx) now, then
1457 subsequently we only need consider the normal path. */
1462 finally
= gimple_eh_else_e_body (eh_else
);
1463 lower_eh_constructs_1 (state
, &finally
);
1465 emit_post_landing_pad (&eh_seq
, tf
->region
);
1466 gimple_seq_add_seq (&eh_seq
, finally
);
1467 emit_resx (&eh_seq
, tf
->region
);
1470 finally
= gimple_eh_else_n_body (eh_else
);
1472 else if (tf
->may_throw
)
1474 emit_post_landing_pad (&eh_seq
, tf
->region
);
1476 x
= gimple_build_assign (finally_tmp
,
1477 build_int_cst (integer_type_node
, eh_index
));
1478 gimple_seq_add_stmt (&eh_seq
, x
);
1480 x
= gimple_build_goto (finally_label
);
1481 gimple_set_location (x
, tf_loc
);
1482 gimple_seq_add_stmt (&eh_seq
, x
);
1484 tmp
= build_int_cst (integer_type_node
, eh_index
);
1485 last_case
= build_case_label (tmp
, NULL
,
1486 create_artificial_label (tf_loc
));
1487 case_label_vec
.quick_push (last_case
);
1490 x
= gimple_build_label (CASE_LABEL (last_case
));
1491 gimple_seq_add_stmt (&eh_seq
, x
);
1492 emit_resx (&eh_seq
, tf
->region
);
1495 x
= gimple_build_label (finally_label
);
1496 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1498 lower_eh_constructs_1 (state
, &finally
);
1499 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1501 /* Redirect each incoming goto edge. */
1503 qe
= q
+ tf
->goto_queue_active
;
1504 j
= last_case_index
+ tf
->may_return
;
1505 /* Prepare the assignments to finally_tmp that are executed upon the
1506 entrance through a particular edge. */
1509 gimple_seq mod
= NULL
;
1511 unsigned int case_index
;
1515 x
= gimple_build_assign (finally_tmp
,
1516 build_int_cst (integer_type_node
,
1518 gimple_seq_add_stmt (&mod
, x
);
1519 do_return_redirection (q
, finally_label
, mod
);
1520 switch_id
= return_index
;
1524 x
= gimple_build_assign (finally_tmp
,
1525 build_int_cst (integer_type_node
, q
->index
));
1526 gimple_seq_add_stmt (&mod
, x
);
1527 do_goto_redirection (q
, finally_label
, mod
, tf
);
1528 switch_id
= q
->index
;
1531 case_index
= j
+ q
->index
;
1532 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1535 tmp
= build_int_cst (integer_type_node
, switch_id
);
1536 case_lab
= build_case_label (tmp
, NULL
,
1537 create_artificial_label (tf_loc
));
1538 /* We store the cont_stmt in the pointer map, so that we can recover
1539 it in the loop below. */
1541 cont_map
= new hash_map
<tree
, gimple
>;
1542 cont_map
->put (case_lab
, q
->cont_stmt
);
1543 case_label_vec
.quick_push (case_lab
);
1546 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1550 last_case
= case_label_vec
[j
];
1552 gcc_assert (last_case
);
1553 gcc_assert (cont_map
);
1555 cont_stmt
= *cont_map
->get (last_case
);
1557 x
= gimple_build_label (CASE_LABEL (last_case
));
1558 gimple_seq_add_stmt (&switch_body
, x
);
1559 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1560 maybe_record_in_goto_queue (state
, cont_stmt
);
1565 replace_goto_queue (tf
);
1567 /* Make sure that the last case is the default label, as one is required.
1568 Then sort the labels, which is also required in GIMPLE. */
1569 CASE_LOW (last_case
) = NULL
;
1570 tree tem
= case_label_vec
.pop ();
1571 gcc_assert (tem
== last_case
);
1572 sort_case_labels (case_label_vec
);
1574 /* Build the switch statement, setting last_case to be the default
1576 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1578 gimple_set_location (switch_stmt
, finally_loc
);
1580 /* Need to link SWITCH_STMT after running replace_goto_queue
1581 due to not wanting to process the same goto stmts twice. */
1582 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1583 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1586 /* Decide whether or not we are going to duplicate the finally block.
1587 There are several considerations.
1589 First, if this is Java, then the finally block contains code
1590 written by the user. It has line numbers associated with it,
1591 so duplicating the block means it's difficult to set a breakpoint.
1592 Since controlling code generation via -g is verboten, we simply
1593 never duplicate code without optimization.
1595 Second, we'd like to prevent egregious code growth. One way to
1596 do this is to estimate the size of the finally block, multiply
1597 that by the number of copies we'd need to make, and compare against
1598 the estimate of the size of the switch machinery we'd have to add. */
1601 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1603 int f_estimate
, sw_estimate
;
1606 /* If there's an EH_ELSE involved, the exception path is separate
1607 and really doesn't come into play for this computation. */
1608 eh_else
= get_eh_else (finally
);
1611 ndests
-= may_throw
;
1612 finally
= gimple_eh_else_n_body (eh_else
);
1617 gimple_stmt_iterator gsi
;
1622 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1624 gimple stmt
= gsi_stmt (gsi
);
1625 if (!is_gimple_debug (stmt
) && !gimple_clobber_p (stmt
))
1631 /* Finally estimate N times, plus N gotos. */
1632 f_estimate
= count_insns_seq (finally
, &eni_size_weights
);
1633 f_estimate
= (f_estimate
+ 1) * ndests
;
1635 /* Switch statement (cost 10), N variable assignments, N gotos. */
1636 sw_estimate
= 10 + 2 * ndests
;
1638 /* Optimize for size clearly wants our best guess. */
1639 if (optimize_function_for_size_p (cfun
))
1640 return f_estimate
< sw_estimate
;
1642 /* ??? These numbers are completely made up so far. */
1644 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1646 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1649 /* REG is the enclosing region for a possible cleanup region, or the region
1650 itself. Returns TRUE if such a region would be unreachable.
1652 Cleanup regions within a must-not-throw region aren't actually reachable
1653 even if there are throwing stmts within them, because the personality
1654 routine will call terminate before unwinding. */
1657 cleanup_is_dead_in (eh_region reg
)
1659 while (reg
&& reg
->type
== ERT_CLEANUP
)
1661 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1664 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1665 to a sequence of labels and blocks, plus the exception region trees
1666 that record all the magic. This is complicated by the need to
1667 arrange for the FINALLY block to be executed on all exits. */
1670 lower_try_finally (struct leh_state
*state
, gtry
*tp
)
1672 struct leh_tf_state this_tf
;
1673 struct leh_state this_state
;
1675 gimple_seq old_eh_seq
;
1677 /* Process the try block. */
1679 memset (&this_tf
, 0, sizeof (this_tf
));
1680 this_tf
.try_finally_expr
= tp
;
1682 this_tf
.outer
= state
;
1683 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
->cur_region
))
1685 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1686 this_state
.cur_region
= this_tf
.region
;
1690 this_tf
.region
= NULL
;
1691 this_state
.cur_region
= state
->cur_region
;
1694 this_state
.ehp_region
= state
->ehp_region
;
1695 this_state
.tf
= &this_tf
;
1697 old_eh_seq
= eh_seq
;
1700 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1702 /* Determine if the try block is escaped through the bottom. */
1703 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1705 /* Determine if any exceptions are possible within the try block. */
1707 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1708 if (this_tf
.may_throw
)
1709 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1711 /* Determine how many edges (still) reach the finally block. Or rather,
1712 how many destinations are reached by the finally block. Use this to
1713 determine how we process the finally block itself. */
1715 ndests
= this_tf
.dest_array
.length ();
1716 ndests
+= this_tf
.may_fallthru
;
1717 ndests
+= this_tf
.may_return
;
1718 ndests
+= this_tf
.may_throw
;
1720 /* If the FINALLY block is not reachable, dike it out. */
1723 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1724 gimple_try_set_cleanup (tp
, NULL
);
1726 /* If the finally block doesn't fall through, then any destination
1727 we might try to impose there isn't reached either. There may be
1728 some minor amount of cleanup and redirection still needed. */
1729 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1730 lower_try_finally_nofallthru (state
, &this_tf
);
1732 /* We can easily special-case redirection to a single destination. */
1733 else if (ndests
== 1)
1734 lower_try_finally_onedest (state
, &this_tf
);
1735 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1736 gimple_try_cleanup (tp
)))
1737 lower_try_finally_copy (state
, &this_tf
);
1739 lower_try_finally_switch (state
, &this_tf
);
1741 /* If someone requested we add a label at the end of the transformed
1743 if (this_tf
.fallthru_label
)
1745 /* This must be reached only if ndests == 0. */
1746 gimple x
= gimple_build_label (this_tf
.fallthru_label
);
1747 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1750 this_tf
.dest_array
.release ();
1751 free (this_tf
.goto_queue
);
1752 if (this_tf
.goto_queue_map
)
1753 delete this_tf
.goto_queue_map
;
1755 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1756 If there was no old eh_seq, then the append is trivially already done. */
1760 eh_seq
= old_eh_seq
;
1763 gimple_seq new_eh_seq
= eh_seq
;
1764 eh_seq
= old_eh_seq
;
1765 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1769 return this_tf
.top_p_seq
;
1772 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1773 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1774 exception region trees that records all the magic. */
1777 lower_catch (struct leh_state
*state
, gtry
*tp
)
1779 eh_region try_region
= NULL
;
1780 struct leh_state this_state
= *state
;
1781 gimple_stmt_iterator gsi
;
1783 gimple_seq new_seq
, cleanup
;
1785 location_t try_catch_loc
= gimple_location (tp
);
1787 if (flag_exceptions
)
1789 try_region
= gen_eh_region_try (state
->cur_region
);
1790 this_state
.cur_region
= try_region
;
1793 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1795 if (!eh_region_may_contain_throw (try_region
))
1796 return gimple_try_eval (tp
);
1799 emit_eh_dispatch (&new_seq
, try_region
);
1800 emit_resx (&new_seq
, try_region
);
1802 this_state
.cur_region
= state
->cur_region
;
1803 this_state
.ehp_region
= try_region
;
1806 cleanup
= gimple_try_cleanup (tp
);
1807 for (gsi
= gsi_start (cleanup
);
1815 catch_stmt
= as_a
<gcatch
*> (gsi_stmt (gsi
));
1816 c
= gen_eh_region_catch (try_region
, gimple_catch_types (catch_stmt
));
1818 handler
= gimple_catch_handler (catch_stmt
);
1819 lower_eh_constructs_1 (&this_state
, &handler
);
1821 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1822 x
= gimple_build_label (c
->label
);
1823 gimple_seq_add_stmt (&new_seq
, x
);
1825 gimple_seq_add_seq (&new_seq
, handler
);
1827 if (gimple_seq_may_fallthru (new_seq
))
1830 out_label
= create_artificial_label (try_catch_loc
);
1832 x
= gimple_build_goto (out_label
);
1833 gimple_seq_add_stmt (&new_seq
, x
);
1839 gimple_try_set_cleanup (tp
, new_seq
);
1841 return frob_into_branch_around (tp
, try_region
, out_label
);
1844 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1845 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1846 region trees that record all the magic. */
1849 lower_eh_filter (struct leh_state
*state
, gtry
*tp
)
1851 struct leh_state this_state
= *state
;
1852 eh_region this_region
= NULL
;
1856 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1858 if (flag_exceptions
)
1860 this_region
= gen_eh_region_allowed (state
->cur_region
,
1861 gimple_eh_filter_types (inner
));
1862 this_state
.cur_region
= this_region
;
1865 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1867 if (!eh_region_may_contain_throw (this_region
))
1868 return gimple_try_eval (tp
);
1871 this_state
.cur_region
= state
->cur_region
;
1872 this_state
.ehp_region
= this_region
;
1874 emit_eh_dispatch (&new_seq
, this_region
);
1875 emit_resx (&new_seq
, this_region
);
1877 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1878 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1879 gimple_seq_add_stmt (&new_seq
, x
);
1881 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1882 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1884 gimple_try_set_cleanup (tp
, new_seq
);
1886 return frob_into_branch_around (tp
, this_region
, NULL
);
1889 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1890 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1891 plus the exception region trees that record all the magic. */
1894 lower_eh_must_not_throw (struct leh_state
*state
, gtry
*tp
)
1896 struct leh_state this_state
= *state
;
1898 if (flag_exceptions
)
1900 gimple inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1901 eh_region this_region
;
1903 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1904 this_region
->u
.must_not_throw
.failure_decl
1905 = gimple_eh_must_not_throw_fndecl (
1906 as_a
<geh_mnt
*> (inner
));
1907 this_region
->u
.must_not_throw
.failure_loc
1908 = LOCATION_LOCUS (gimple_location (tp
));
1910 /* In order to get mangling applied to this decl, we must mark it
1911 used now. Otherwise, pass_ipa_free_lang_data won't think it
1913 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1915 this_state
.cur_region
= this_region
;
1918 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1920 return gimple_try_eval (tp
);
1923 /* Implement a cleanup expression. This is similar to try-finally,
1924 except that we only execute the cleanup block for exception edges. */
1927 lower_cleanup (struct leh_state
*state
, gtry
*tp
)
1929 struct leh_state this_state
= *state
;
1930 eh_region this_region
= NULL
;
1931 struct leh_tf_state fake_tf
;
1933 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1935 if (flag_exceptions
&& !cleanup_dead
)
1937 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1938 this_state
.cur_region
= this_region
;
1941 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1943 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1944 return gimple_try_eval (tp
);
1946 /* Build enough of a try-finally state so that we can reuse
1947 honor_protect_cleanup_actions. */
1948 memset (&fake_tf
, 0, sizeof (fake_tf
));
1949 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1950 fake_tf
.outer
= state
;
1951 fake_tf
.region
= this_region
;
1952 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1953 fake_tf
.may_throw
= true;
1955 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1957 if (fake_tf
.may_throw
)
1959 /* In this case honor_protect_cleanup_actions had nothing to do,
1960 and we should process this normally. */
1961 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1962 result
= frob_into_branch_around (tp
, this_region
,
1963 fake_tf
.fallthru_label
);
1967 /* In this case honor_protect_cleanup_actions did nearly all of
1968 the work. All we have left is to append the fallthru_label. */
1970 result
= gimple_try_eval (tp
);
1971 if (fake_tf
.fallthru_label
)
1973 gimple x
= gimple_build_label (fake_tf
.fallthru_label
);
1974 gimple_seq_add_stmt (&result
, x
);
1980 /* Main loop for lowering eh constructs. Also moves gsi to the next
1984 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1988 gimple stmt
= gsi_stmt (*gsi
);
1990 switch (gimple_code (stmt
))
1994 tree fndecl
= gimple_call_fndecl (stmt
);
1997 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1998 switch (DECL_FUNCTION_CODE (fndecl
))
2000 case BUILT_IN_EH_POINTER
:
2001 /* The front end may have generated a call to
2002 __builtin_eh_pointer (0) within a catch region. Replace
2003 this zero argument with the current catch region number. */
2004 if (state
->ehp_region
)
2006 tree nr
= build_int_cst (integer_type_node
,
2007 state
->ehp_region
->index
);
2008 gimple_call_set_arg (stmt
, 0, nr
);
2012 /* The user has dome something silly. Remove it. */
2013 rhs
= null_pointer_node
;
2018 case BUILT_IN_EH_FILTER
:
2019 /* ??? This should never appear, but since it's a builtin it
2020 is accessible to abuse by users. Just remove it and
2021 replace the use with the arbitrary value zero. */
2022 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2024 lhs
= gimple_call_lhs (stmt
);
2025 x
= gimple_build_assign (lhs
, rhs
);
2026 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2029 case BUILT_IN_EH_COPY_VALUES
:
2030 /* Likewise this should not appear. Remove it. */
2031 gsi_remove (gsi
, true);
2041 /* If the stmt can throw use a new temporary for the assignment
2042 to a LHS. This makes sure the old value of the LHS is
2043 available on the EH edge. Only do so for statements that
2044 potentially fall through (no noreturn calls e.g.), otherwise
2045 this new assignment might create fake fallthru regions. */
2046 if (stmt_could_throw_p (stmt
)
2047 && gimple_has_lhs (stmt
)
2048 && gimple_stmt_may_fallthru (stmt
)
2049 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2050 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2052 tree lhs
= gimple_get_lhs (stmt
);
2053 tree tmp
= create_tmp_var (TREE_TYPE (lhs
));
2054 gimple s
= gimple_build_assign (lhs
, tmp
);
2055 gimple_set_location (s
, gimple_location (stmt
));
2056 gimple_set_block (s
, gimple_block (stmt
));
2057 gimple_set_lhs (stmt
, tmp
);
2058 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2059 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2060 DECL_GIMPLE_REG_P (tmp
) = 1;
2061 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2063 /* Look for things that can throw exceptions, and record them. */
2064 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
2066 record_stmt_eh_region (state
->cur_region
, stmt
);
2067 note_eh_region_may_contain_throw (state
->cur_region
);
2074 maybe_record_in_goto_queue (state
, stmt
);
2078 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2083 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2084 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2085 replace
= lower_try_finally (state
, try_stmt
);
2088 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2091 replace
= gimple_try_eval (try_stmt
);
2092 lower_eh_constructs_1 (state
, &replace
);
2095 switch (gimple_code (x
))
2098 replace
= lower_catch (state
, try_stmt
);
2100 case GIMPLE_EH_FILTER
:
2101 replace
= lower_eh_filter (state
, try_stmt
);
2103 case GIMPLE_EH_MUST_NOT_THROW
:
2104 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2106 case GIMPLE_EH_ELSE
:
2107 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2110 replace
= lower_cleanup (state
, try_stmt
);
2116 /* Remove the old stmt and insert the transformed sequence
2118 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2119 gsi_remove (gsi
, true);
2121 /* Return since we don't want gsi_next () */
2124 case GIMPLE_EH_ELSE
:
2125 /* We should be eliminating this in lower_try_finally et al. */
2129 /* A type, a decl, or some kind of statement that we're not
2130 interested in. Don't walk them. */
2137 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2140 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2142 gimple_stmt_iterator gsi
;
2143 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2144 lower_eh_constructs_2 (state
, &gsi
);
2149 const pass_data pass_data_lower_eh
=
2151 GIMPLE_PASS
, /* type */
2153 OPTGROUP_NONE
, /* optinfo_flags */
2154 TV_TREE_EH
, /* tv_id */
2155 PROP_gimple_lcf
, /* properties_required */
2156 PROP_gimple_leh
, /* properties_provided */
2157 0, /* properties_destroyed */
2158 0, /* todo_flags_start */
2159 0, /* todo_flags_finish */
2162 class pass_lower_eh
: public gimple_opt_pass
2165 pass_lower_eh (gcc::context
*ctxt
)
2166 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2169 /* opt_pass methods: */
2170 virtual unsigned int execute (function
*);
2172 }; // class pass_lower_eh
2175 pass_lower_eh::execute (function
*fun
)
2177 struct leh_state null_state
;
2180 bodyp
= gimple_body (current_function_decl
);
2184 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2185 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2186 memset (&null_state
, 0, sizeof (null_state
));
2188 collect_finally_tree_1 (bodyp
, NULL
);
2189 lower_eh_constructs_1 (&null_state
, &bodyp
);
2190 gimple_set_body (current_function_decl
, bodyp
);
2192 /* We assume there's a return statement, or something, at the end of
2193 the function, and thus ploping the EH sequence afterward won't
2195 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2196 gimple_seq_add_seq (&bodyp
, eh_seq
);
2198 /* We assume that since BODYP already existed, adding EH_SEQ to it
2199 didn't change its value, and we don't have to re-set the function. */
2200 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2202 delete finally_tree
;
2203 finally_tree
= NULL
;
2204 BITMAP_FREE (eh_region_may_contain_throw_map
);
2207 /* If this function needs a language specific EH personality routine
2208 and the frontend didn't already set one do so now. */
2209 if (function_needs_eh_personality (fun
) == eh_personality_lang
2210 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2211 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2212 = lang_hooks
.eh_personality ();
2220 make_pass_lower_eh (gcc::context
*ctxt
)
2222 return new pass_lower_eh (ctxt
);
2225 /* Create the multiple edges from an EH_DISPATCH statement to all of
2226 the possible handlers for its EH region. Return true if there's
2227 no fallthru edge; false if there is. */
2230 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2234 basic_block src
, dst
;
2236 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2237 src
= gimple_bb (stmt
);
2242 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2244 dst
= label_to_block (c
->label
);
2245 make_edge (src
, dst
, 0);
2247 /* A catch-all handler doesn't have a fallthru. */
2248 if (c
->type_list
== NULL
)
2253 case ERT_ALLOWED_EXCEPTIONS
:
2254 dst
= label_to_block (r
->u
.allowed
.label
);
2255 make_edge (src
, dst
, 0);
2265 /* Create the single EH edge from STMT to its nearest landing pad,
2266 if there is such a landing pad within the current function. */
2269 make_eh_edges (gimple stmt
)
2271 basic_block src
, dst
;
2275 lp_nr
= lookup_stmt_eh_lp (stmt
);
2279 lp
= get_eh_landing_pad_from_number (lp_nr
);
2280 gcc_assert (lp
!= NULL
);
2282 src
= gimple_bb (stmt
);
2283 dst
= label_to_block (lp
->post_landing_pad
);
2284 make_edge (src
, dst
, EDGE_EH
);
2287 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2288 do not actually perform the final edge redirection.
2290 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2291 we intend to change the destination EH region as well; this means
2292 EH_LANDING_PAD_NR must already be set on the destination block label.
2293 If false, we're being called from generic cfg manipulation code and we
2294 should preserve our place within the region tree. */
2297 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2299 eh_landing_pad old_lp
, new_lp
;
2302 int old_lp_nr
, new_lp_nr
;
2303 tree old_label
, new_label
;
2307 old_bb
= edge_in
->dest
;
2308 old_label
= gimple_block_label (old_bb
);
2309 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2310 gcc_assert (old_lp_nr
> 0);
2311 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2313 throw_stmt
= last_stmt (edge_in
->src
);
2314 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2316 new_label
= gimple_block_label (new_bb
);
2318 /* Look for an existing region that might be using NEW_BB already. */
2319 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2322 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2323 gcc_assert (new_lp
);
2325 /* Unless CHANGE_REGION is true, the new and old landing pad
2326 had better be associated with the same EH region. */
2327 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2332 gcc_assert (!change_region
);
2335 /* Notice when we redirect the last EH edge away from OLD_BB. */
2336 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2337 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2342 /* NEW_LP already exists. If there are still edges into OLD_LP,
2343 there's nothing to do with the EH tree. If there are no more
2344 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2345 If CHANGE_REGION is true, then our caller is expecting to remove
2347 if (e
== NULL
&& !change_region
)
2348 remove_eh_landing_pad (old_lp
);
2352 /* No correct landing pad exists. If there are no more edges
2353 into OLD_LP, then we can simply re-use the existing landing pad.
2354 Otherwise, we have to create a new landing pad. */
2357 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2361 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2362 new_lp
->post_landing_pad
= new_label
;
2363 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2366 /* Maybe move the throwing statement to the new region. */
2367 if (old_lp
!= new_lp
)
2369 remove_stmt_from_eh_lp (throw_stmt
);
2370 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2374 /* Redirect EH edge E to NEW_BB. */
2377 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2379 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2380 return ssa_redirect_edge (edge_in
, new_bb
);
2383 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2384 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2385 The actual edge update will happen in the caller. */
2388 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2390 tree new_lab
= gimple_block_label (new_bb
);
2391 bool any_changed
= false;
2396 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2400 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2402 old_bb
= label_to_block (c
->label
);
2403 if (old_bb
== e
->dest
)
2411 case ERT_ALLOWED_EXCEPTIONS
:
2412 old_bb
= label_to_block (r
->u
.allowed
.label
);
2413 gcc_assert (old_bb
== e
->dest
);
2414 r
->u
.allowed
.label
= new_lab
;
2422 gcc_assert (any_changed
);
2425 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2428 operation_could_trap_helper_p (enum tree_code op
,
2439 case TRUNC_DIV_EXPR
:
2441 case FLOOR_DIV_EXPR
:
2442 case ROUND_DIV_EXPR
:
2443 case EXACT_DIV_EXPR
:
2445 case FLOOR_MOD_EXPR
:
2446 case ROUND_MOD_EXPR
:
2447 case TRUNC_MOD_EXPR
:
2449 if (honor_snans
|| honor_trapv
)
2452 return flag_trapping_math
;
2453 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2462 /* Some floating point comparisons may trap. */
2467 case UNORDERED_EXPR
:
2479 /* These operations don't trap with floating point. */
2487 /* Any floating arithmetic may trap. */
2488 if (fp_operation
&& flag_trapping_math
)
2496 /* Constructing an object cannot trap. */
2500 /* Any floating arithmetic may trap. */
2501 if (fp_operation
&& flag_trapping_math
)
2509 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2510 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2511 type operands that may trap. If OP is a division operator, DIVISOR contains
2512 the value of the divisor. */
2515 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2518 bool honor_nans
= (fp_operation
&& flag_trapping_math
2519 && !flag_finite_math_only
);
2520 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2523 if (TREE_CODE_CLASS (op
) != tcc_comparison
2524 && TREE_CODE_CLASS (op
) != tcc_unary
2525 && TREE_CODE_CLASS (op
) != tcc_binary
)
2528 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2529 honor_nans
, honor_snans
, divisor
,
2534 /* Returns true if it is possible to prove that the index of
2535 an array access REF (an ARRAY_REF expression) falls into the
2539 in_array_bounds_p (tree ref
)
2541 tree idx
= TREE_OPERAND (ref
, 1);
2544 if (TREE_CODE (idx
) != INTEGER_CST
)
2547 min
= array_ref_low_bound (ref
);
2548 max
= array_ref_up_bound (ref
);
2551 || TREE_CODE (min
) != INTEGER_CST
2552 || TREE_CODE (max
) != INTEGER_CST
)
2555 if (tree_int_cst_lt (idx
, min
)
2556 || tree_int_cst_lt (max
, idx
))
2562 /* Returns true if it is possible to prove that the range of
2563 an array access REF (an ARRAY_RANGE_REF expression) falls
2564 into the array bounds. */
2567 range_in_array_bounds_p (tree ref
)
2569 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2570 tree range_min
, range_max
, min
, max
;
2572 range_min
= TYPE_MIN_VALUE (domain_type
);
2573 range_max
= TYPE_MAX_VALUE (domain_type
);
2576 || TREE_CODE (range_min
) != INTEGER_CST
2577 || TREE_CODE (range_max
) != INTEGER_CST
)
2580 min
= array_ref_low_bound (ref
);
2581 max
= array_ref_up_bound (ref
);
2584 || TREE_CODE (min
) != INTEGER_CST
2585 || TREE_CODE (max
) != INTEGER_CST
)
2588 if (tree_int_cst_lt (range_min
, min
)
2589 || tree_int_cst_lt (max
, range_max
))
2595 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2596 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2597 This routine expects only GIMPLE lhs or rhs input. */
2600 tree_could_trap_p (tree expr
)
2602 enum tree_code code
;
2603 bool fp_operation
= false;
2604 bool honor_trapv
= false;
2605 tree t
, base
, div
= NULL_TREE
;
2610 code
= TREE_CODE (expr
);
2611 t
= TREE_TYPE (expr
);
2615 if (COMPARISON_CLASS_P (expr
))
2616 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2618 fp_operation
= FLOAT_TYPE_P (t
);
2619 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2622 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2623 div
= TREE_OPERAND (expr
, 1);
2624 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2634 case VIEW_CONVERT_EXPR
:
2635 case WITH_SIZE_EXPR
:
2636 expr
= TREE_OPERAND (expr
, 0);
2637 code
= TREE_CODE (expr
);
2640 case ARRAY_RANGE_REF
:
2641 base
= TREE_OPERAND (expr
, 0);
2642 if (tree_could_trap_p (base
))
2644 if (TREE_THIS_NOTRAP (expr
))
2646 return !range_in_array_bounds_p (expr
);
2649 base
= TREE_OPERAND (expr
, 0);
2650 if (tree_could_trap_p (base
))
2652 if (TREE_THIS_NOTRAP (expr
))
2654 return !in_array_bounds_p (expr
);
2656 case TARGET_MEM_REF
:
2658 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2659 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2661 if (TREE_THIS_NOTRAP (expr
))
2663 /* We cannot prove that the access is in-bounds when we have
2664 variable-index TARGET_MEM_REFs. */
2665 if (code
== TARGET_MEM_REF
2666 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2668 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2670 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2671 offset_int off
= mem_ref_offset (expr
);
2672 if (wi::neg_p (off
, SIGNED
))
2674 if (TREE_CODE (base
) == STRING_CST
)
2675 return wi::leu_p (TREE_STRING_LENGTH (base
), off
);
2676 else if (DECL_SIZE_UNIT (base
) == NULL_TREE
2677 || TREE_CODE (DECL_SIZE_UNIT (base
)) != INTEGER_CST
2678 || wi::leu_p (wi::to_offset (DECL_SIZE_UNIT (base
)), off
))
2680 /* Now we are sure the first byte of the access is inside
2687 return !TREE_THIS_NOTRAP (expr
);
2690 return TREE_THIS_VOLATILE (expr
);
2693 t
= get_callee_fndecl (expr
);
2694 /* Assume that calls to weak functions may trap. */
2695 if (!t
|| !DECL_P (t
))
2698 return tree_could_trap_p (t
);
2702 /* Assume that accesses to weak functions may trap, unless we know
2703 they are certainly defined in current TU or in some other
2705 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2707 cgraph_node
*node
= cgraph_node::get (expr
);
2709 node
= node
->function_symbol ();
2710 return !(node
&& node
->in_other_partition
);
2715 /* Assume that accesses to weak vars may trap, unless we know
2716 they are certainly defined in current TU or in some other
2718 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2720 varpool_node
*node
= varpool_node::get (expr
);
2722 node
= node
->ultimate_alias_target ();
2723 return !(node
&& node
->in_other_partition
);
2733 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2734 an assignment or a conditional) may throw. */
2737 stmt_could_throw_1_p (gimple stmt
)
2739 enum tree_code code
= gimple_expr_code (stmt
);
2740 bool honor_nans
= false;
2741 bool honor_snans
= false;
2742 bool fp_operation
= false;
2743 bool honor_trapv
= false;
2748 if (TREE_CODE_CLASS (code
) == tcc_comparison
2749 || TREE_CODE_CLASS (code
) == tcc_unary
2750 || TREE_CODE_CLASS (code
) == tcc_binary
)
2752 if (is_gimple_assign (stmt
)
2753 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2754 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2755 else if (gimple_code (stmt
) == GIMPLE_COND
)
2756 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2758 t
= gimple_expr_type (stmt
);
2759 fp_operation
= FLOAT_TYPE_P (t
);
2762 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2763 honor_snans
= flag_signaling_nans
!= 0;
2765 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2769 /* Check if the main expression may trap. */
2770 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2771 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2772 honor_nans
, honor_snans
, t
,
2777 /* If the expression does not trap, see if any of the individual operands may
2779 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2780 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2787 /* Return true if statement STMT could throw an exception. */
2790 stmt_could_throw_p (gimple stmt
)
2792 if (!flag_exceptions
)
2795 /* The only statements that can throw an exception are assignments,
2796 conditionals, calls, resx, and asms. */
2797 switch (gimple_code (stmt
))
2803 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2807 if (!cfun
->can_throw_non_call_exceptions
)
2809 return stmt_could_throw_1_p (stmt
);
2812 if (!cfun
->can_throw_non_call_exceptions
)
2814 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2822 /* Return true if expression T could throw an exception. */
2825 tree_could_throw_p (tree t
)
2827 if (!flag_exceptions
)
2829 if (TREE_CODE (t
) == MODIFY_EXPR
)
2831 if (cfun
->can_throw_non_call_exceptions
2832 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2834 t
= TREE_OPERAND (t
, 1);
2837 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2838 t
= TREE_OPERAND (t
, 0);
2839 if (TREE_CODE (t
) == CALL_EXPR
)
2840 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2841 if (cfun
->can_throw_non_call_exceptions
)
2842 return tree_could_trap_p (t
);
2846 /* Return true if STMT can throw an exception that is not caught within
2847 the current function (CFUN). */
2850 stmt_can_throw_external (gimple stmt
)
2854 if (!stmt_could_throw_p (stmt
))
2857 lp_nr
= lookup_stmt_eh_lp (stmt
);
2861 /* Return true if STMT can throw an exception that is caught within
2862 the current function (CFUN). */
2865 stmt_can_throw_internal (gimple stmt
)
2869 if (!stmt_could_throw_p (stmt
))
2872 lp_nr
= lookup_stmt_eh_lp (stmt
);
2876 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2877 remove any entry it might have from the EH table. Return true if
2878 any change was made. */
2881 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple stmt
)
2883 if (stmt_could_throw_p (stmt
))
2885 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2888 /* Likewise, but always use the current function. */
2891 maybe_clean_eh_stmt (gimple stmt
)
2893 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2896 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2897 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2898 in the table if it should be in there. Return TRUE if a replacement was
2899 done that my require an EH edge purge. */
2902 maybe_clean_or_replace_eh_stmt (gimple old_stmt
, gimple new_stmt
)
2904 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2908 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2910 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2913 remove_stmt_from_eh_lp (old_stmt
);
2914 if (new_stmt_could_throw
)
2916 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2926 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2927 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2928 operand is the return value of duplicate_eh_regions. */
2931 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple new_stmt
,
2932 struct function
*old_fun
, gimple old_stmt
,
2933 hash_map
<void *, void *> *map
,
2936 int old_lp_nr
, new_lp_nr
;
2938 if (!stmt_could_throw_p (new_stmt
))
2941 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2944 if (default_lp_nr
== 0)
2946 new_lp_nr
= default_lp_nr
;
2948 else if (old_lp_nr
> 0)
2950 eh_landing_pad old_lp
, new_lp
;
2952 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
2953 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
2954 new_lp_nr
= new_lp
->index
;
2958 eh_region old_r
, new_r
;
2960 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
2961 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
2962 new_lp_nr
= -new_r
->index
;
2965 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2969 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2970 and thus no remapping is required. */
2973 maybe_duplicate_eh_stmt (gimple new_stmt
, gimple old_stmt
)
2977 if (!stmt_could_throw_p (new_stmt
))
2980 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2984 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2988 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2989 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2990 this only handles handlers consisting of a single call, as that's the
2991 important case for C++: a destructor call for a particular object showing
2992 up in multiple handlers. */
2995 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2997 gimple_stmt_iterator gsi
;
3001 gsi
= gsi_start (oneh
);
3002 if (!gsi_one_before_end_p (gsi
))
3004 ones
= gsi_stmt (gsi
);
3006 gsi
= gsi_start (twoh
);
3007 if (!gsi_one_before_end_p (gsi
))
3009 twos
= gsi_stmt (gsi
);
3011 if (!is_gimple_call (ones
)
3012 || !is_gimple_call (twos
)
3013 || gimple_call_lhs (ones
)
3014 || gimple_call_lhs (twos
)
3015 || gimple_call_chain (ones
)
3016 || gimple_call_chain (twos
)
3017 || !gimple_call_same_target_p (ones
, twos
)
3018 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3021 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3022 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3023 gimple_call_arg (twos
, ai
), 0))
3030 try { A() } finally { try { ~B() } catch { ~A() } }
3031 try { ... } finally { ~A() }
3033 try { A() } catch { ~B() }
3034 try { ~B() ... } finally { ~A() }
3036 This occurs frequently in C++, where A is a local variable and B is a
3037 temporary used in the initializer for A. */
3040 optimize_double_finally (gtry
*one
, gtry
*two
)
3043 gimple_stmt_iterator gsi
;
3046 cleanup
= gimple_try_cleanup (one
);
3047 gsi
= gsi_start (cleanup
);
3048 if (!gsi_one_before_end_p (gsi
))
3051 oneh
= gsi_stmt (gsi
);
3052 if (gimple_code (oneh
) != GIMPLE_TRY
3053 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3056 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3058 gimple_seq seq
= gimple_try_eval (oneh
);
3060 gimple_try_set_cleanup (one
, seq
);
3061 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3062 seq
= copy_gimple_seq_and_replace_locals (seq
);
3063 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3064 gimple_try_set_eval (two
, seq
);
3068 /* Perform EH refactoring optimizations that are simpler to do when code
3069 flow has been lowered but EH structures haven't. */
3072 refactor_eh_r (gimple_seq seq
)
3074 gimple_stmt_iterator gsi
;
3079 gsi
= gsi_start (seq
);
3083 if (gsi_end_p (gsi
))
3086 two
= gsi_stmt (gsi
);
3088 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3089 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3090 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3091 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3092 optimize_double_finally (try_one
, try_two
);
3094 switch (gimple_code (one
))
3097 refactor_eh_r (gimple_try_eval (one
));
3098 refactor_eh_r (gimple_try_cleanup (one
));
3101 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3103 case GIMPLE_EH_FILTER
:
3104 refactor_eh_r (gimple_eh_filter_failure (one
));
3106 case GIMPLE_EH_ELSE
:
3108 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3109 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3110 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3125 const pass_data pass_data_refactor_eh
=
3127 GIMPLE_PASS
, /* type */
3129 OPTGROUP_NONE
, /* optinfo_flags */
3130 TV_TREE_EH
, /* tv_id */
3131 PROP_gimple_lcf
, /* properties_required */
3132 0, /* properties_provided */
3133 0, /* properties_destroyed */
3134 0, /* todo_flags_start */
3135 0, /* todo_flags_finish */
3138 class pass_refactor_eh
: public gimple_opt_pass
3141 pass_refactor_eh (gcc::context
*ctxt
)
3142 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3145 /* opt_pass methods: */
3146 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3147 virtual unsigned int execute (function
*)
3149 refactor_eh_r (gimple_body (current_function_decl
));
3153 }; // class pass_refactor_eh
3158 make_pass_refactor_eh (gcc::context
*ctxt
)
3160 return new pass_refactor_eh (ctxt
);
3163 /* At the end of gimple optimization, we can lower RESX. */
3166 lower_resx (basic_block bb
, gresx
*stmt
,
3167 hash_map
<eh_region
, tree
> *mnt_map
)
3170 eh_region src_r
, dst_r
;
3171 gimple_stmt_iterator gsi
;
3176 lp_nr
= lookup_stmt_eh_lp (stmt
);
3178 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3182 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3183 gsi
= gsi_last_bb (bb
);
3187 /* We can wind up with no source region when pass_cleanup_eh shows
3188 that there are no entries into an eh region and deletes it, but
3189 then the block that contains the resx isn't removed. This can
3190 happen without optimization when the switch statement created by
3191 lower_try_finally_switch isn't simplified to remove the eh case.
3193 Resolve this by expanding the resx node to an abort. */
3195 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3196 x
= gimple_build_call (fn
, 0);
3197 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3199 while (EDGE_COUNT (bb
->succs
) > 0)
3200 remove_edge (EDGE_SUCC (bb
, 0));
3204 /* When we have a destination region, we resolve this by copying
3205 the excptr and filter values into place, and changing the edge
3206 to immediately after the landing pad. */
3214 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3215 the failure decl into a new block, if needed. */
3216 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3218 tree
*slot
= mnt_map
->get (dst_r
);
3221 gimple_stmt_iterator gsi2
;
3223 new_bb
= create_empty_bb (bb
);
3224 add_bb_to_loop (new_bb
, bb
->loop_father
);
3225 lab
= gimple_block_label (new_bb
);
3226 gsi2
= gsi_start_bb (new_bb
);
3228 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3229 x
= gimple_build_call (fn
, 0);
3230 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3231 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3233 mnt_map
->put (dst_r
, lab
);
3238 new_bb
= label_to_block (lab
);
3241 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3242 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3243 e
->count
= bb
->count
;
3244 e
->probability
= REG_BR_PROB_BASE
;
3249 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3251 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3252 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3253 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3254 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3256 /* Update the flags for the outgoing edge. */
3257 e
= single_succ_edge (bb
);
3258 gcc_assert (e
->flags
& EDGE_EH
);
3259 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3261 /* If there are no more EH users of the landing pad, delete it. */
3262 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3263 if (e
->flags
& EDGE_EH
)
3267 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3268 remove_eh_landing_pad (lp
);
3278 /* When we don't have a destination region, this exception escapes
3279 up the call chain. We resolve this by generating a call to the
3280 _Unwind_Resume library function. */
3282 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3283 with no arguments for C++ and Java. Check for that. */
3284 if (src_r
->use_cxa_end_cleanup
)
3286 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3287 x
= gimple_build_call (fn
, 0);
3288 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3292 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3293 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3294 x
= gimple_build_call (fn
, 1, src_nr
);
3295 var
= create_tmp_var (ptr_type_node
);
3296 var
= make_ssa_name (var
, x
);
3297 gimple_call_set_lhs (x
, var
);
3298 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3300 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3301 x
= gimple_build_call (fn
, 1, var
);
3302 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3305 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3308 gsi_remove (&gsi
, true);
3315 const pass_data pass_data_lower_resx
=
3317 GIMPLE_PASS
, /* type */
3319 OPTGROUP_NONE
, /* optinfo_flags */
3320 TV_TREE_EH
, /* tv_id */
3321 PROP_gimple_lcf
, /* properties_required */
3322 0, /* properties_provided */
3323 0, /* properties_destroyed */
3324 0, /* todo_flags_start */
3325 0, /* todo_flags_finish */
3328 class pass_lower_resx
: public gimple_opt_pass
3331 pass_lower_resx (gcc::context
*ctxt
)
3332 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3335 /* opt_pass methods: */
3336 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3337 virtual unsigned int execute (function
*);
3339 }; // class pass_lower_resx
3342 pass_lower_resx::execute (function
*fun
)
3345 bool dominance_invalidated
= false;
3346 bool any_rewritten
= false;
3348 hash_map
<eh_region
, tree
> mnt_map
;
3350 FOR_EACH_BB_FN (bb
, fun
)
3352 gimple last
= last_stmt (bb
);
3353 if (last
&& is_gimple_resx (last
))
3355 dominance_invalidated
|=
3356 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3357 any_rewritten
= true;
3361 if (dominance_invalidated
)
3363 free_dominance_info (CDI_DOMINATORS
);
3364 free_dominance_info (CDI_POST_DOMINATORS
);
3367 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3373 make_pass_lower_resx (gcc::context
*ctxt
)
3375 return new pass_lower_resx (ctxt
);
3378 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3382 optimize_clobbers (basic_block bb
)
3384 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3385 bool any_clobbers
= false;
3386 bool seen_stack_restore
= false;
3390 /* Only optimize anything if the bb contains at least one clobber,
3391 ends with resx (checked by caller), optionally contains some
3392 debug stmts or labels, or at most one __builtin_stack_restore
3393 call, and has an incoming EH edge. */
3394 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3396 gimple stmt
= gsi_stmt (gsi
);
3397 if (is_gimple_debug (stmt
))
3399 if (gimple_clobber_p (stmt
))
3401 any_clobbers
= true;
3404 if (!seen_stack_restore
3405 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3407 seen_stack_restore
= true;
3410 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3416 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3417 if (e
->flags
& EDGE_EH
)
3421 gsi
= gsi_last_bb (bb
);
3422 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3424 gimple stmt
= gsi_stmt (gsi
);
3425 if (!gimple_clobber_p (stmt
))
3427 unlink_stmt_vdef (stmt
);
3428 gsi_remove (&gsi
, true);
3429 release_defs (stmt
);
3433 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3434 internal throw to successor BB. */
3437 sink_clobbers (basic_block bb
)
3441 gimple_stmt_iterator gsi
, dgsi
;
3443 bool any_clobbers
= false;
3446 /* Only optimize if BB has a single EH successor and
3447 all predecessor edges are EH too. */
3448 if (!single_succ_p (bb
)
3449 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3452 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3454 if ((e
->flags
& EDGE_EH
) == 0)
3458 /* And BB contains only CLOBBER stmts before the final
3460 gsi
= gsi_last_bb (bb
);
3461 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3463 gimple stmt
= gsi_stmt (gsi
);
3464 if (is_gimple_debug (stmt
))
3466 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3468 if (!gimple_clobber_p (stmt
))
3470 any_clobbers
= true;
3475 edge succe
= single_succ_edge (bb
);
3476 succbb
= succe
->dest
;
3478 /* See if there is a virtual PHI node to take an updated virtual
3481 tree vuse
= NULL_TREE
;
3482 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3483 !gsi_end_p (gpi
); gsi_next (&gpi
))
3485 tree res
= gimple_phi_result (gpi
.phi ());
3486 if (virtual_operand_p (res
))
3494 dgsi
= gsi_after_labels (succbb
);
3495 gsi
= gsi_last_bb (bb
);
3496 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3498 gimple stmt
= gsi_stmt (gsi
);
3500 if (is_gimple_debug (stmt
))
3502 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3504 lhs
= gimple_assign_lhs (stmt
);
3505 /* Unfortunately we don't have dominance info updated at this
3506 point, so checking if
3507 dominated_by_p (CDI_DOMINATORS, succbb,
3508 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3509 would be too costly. Thus, avoid sinking any clobbers that
3510 refer to non-(D) SSA_NAMEs. */
3511 if (TREE_CODE (lhs
) == MEM_REF
3512 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3513 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3515 unlink_stmt_vdef (stmt
);
3516 gsi_remove (&gsi
, true);
3517 release_defs (stmt
);
3521 /* As we do not change stmt order when sinking across a
3522 forwarder edge we can keep virtual operands in place. */
3523 gsi_remove (&gsi
, false);
3524 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3526 /* But adjust virtual operands if we sunk across a PHI node. */
3530 imm_use_iterator iter
;
3531 use_operand_p use_p
;
3532 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, vuse
)
3533 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3534 SET_USE (use_p
, gimple_vdef (stmt
));
3535 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
))
3537 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt
)) = 1;
3538 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
) = 0;
3540 /* Adjust the incoming virtual operand. */
3541 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
), gimple_vuse (stmt
));
3542 SET_USE (gimple_vuse_op (stmt
), vuse
);
3544 /* If there isn't a single predecessor but no virtual PHI node
3545 arrange for virtual operands to be renamed. */
3546 else if (gimple_vuse_op (stmt
) != NULL_USE_OPERAND_P
3547 && !single_pred_p (succbb
))
3549 /* In this case there will be no use of the VDEF of this stmt.
3550 ??? Unless this is a secondary opportunity and we have not
3551 removed unreachable blocks yet, so we cannot assert this.
3552 Which also means we will end up renaming too many times. */
3553 SET_USE (gimple_vuse_op (stmt
), gimple_vop (cfun
));
3554 mark_virtual_operands_for_renaming (cfun
);
3555 todo
|= TODO_update_ssa_only_virtuals
;
3562 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3563 we have found some duplicate labels and removed some edges. */
3566 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3568 gimple_stmt_iterator gsi
;
3573 bool redirected
= false;
3575 region_nr
= gimple_eh_dispatch_region (stmt
);
3576 r
= get_eh_region_from_number (region_nr
);
3578 gsi
= gsi_last_bb (src
);
3584 auto_vec
<tree
> labels
;
3585 tree default_label
= NULL
;
3589 hash_set
<tree
> seen_values
;
3591 /* Collect the labels for a switch. Zero the post_landing_pad
3592 field becase we'll no longer have anything keeping these labels
3593 in existence and the optimizer will be free to merge these
3595 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3597 tree tp_node
, flt_node
, lab
= c
->label
;
3598 bool have_label
= false;
3601 tp_node
= c
->type_list
;
3602 flt_node
= c
->filter_list
;
3604 if (tp_node
== NULL
)
3606 default_label
= lab
;
3611 /* Filter out duplicate labels that arise when this handler
3612 is shadowed by an earlier one. When no labels are
3613 attached to the handler anymore, we remove
3614 the corresponding edge and then we delete unreachable
3615 blocks at the end of this pass. */
3616 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3618 tree t
= build_case_label (TREE_VALUE (flt_node
),
3620 labels
.safe_push (t
);
3621 seen_values
.add (TREE_VALUE (flt_node
));
3625 tp_node
= TREE_CHAIN (tp_node
);
3626 flt_node
= TREE_CHAIN (flt_node
);
3631 remove_edge (find_edge (src
, label_to_block (lab
)));
3636 /* Clean up the edge flags. */
3637 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3639 if (e
->flags
& EDGE_FALLTHRU
)
3641 /* If there was no catch-all, use the fallthru edge. */
3642 if (default_label
== NULL
)
3643 default_label
= gimple_block_label (e
->dest
);
3644 e
->flags
&= ~EDGE_FALLTHRU
;
3647 gcc_assert (default_label
!= NULL
);
3649 /* Don't generate a switch if there's only a default case.
3650 This is common in the form of try { A; } catch (...) { B; }. */
3651 if (!labels
.exists ())
3653 e
= single_succ_edge (src
);
3654 e
->flags
|= EDGE_FALLTHRU
;
3658 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3659 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3661 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3662 filter
= make_ssa_name (filter
, x
);
3663 gimple_call_set_lhs (x
, filter
);
3664 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3666 /* Turn the default label into a default case. */
3667 default_label
= build_case_label (NULL
, NULL
, default_label
);
3668 sort_case_labels (labels
);
3670 x
= gimple_build_switch (filter
, default_label
, labels
);
3671 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3676 case ERT_ALLOWED_EXCEPTIONS
:
3678 edge b_e
= BRANCH_EDGE (src
);
3679 edge f_e
= FALLTHRU_EDGE (src
);
3681 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3682 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3684 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3685 filter
= make_ssa_name (filter
, x
);
3686 gimple_call_set_lhs (x
, filter
);
3687 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3689 r
->u
.allowed
.label
= NULL
;
3690 x
= gimple_build_cond (EQ_EXPR
, filter
,
3691 build_int_cst (TREE_TYPE (filter
),
3692 r
->u
.allowed
.filter
),
3693 NULL_TREE
, NULL_TREE
);
3694 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3696 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3697 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3705 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3706 gsi_remove (&gsi
, true);
3712 const pass_data pass_data_lower_eh_dispatch
=
3714 GIMPLE_PASS
, /* type */
3715 "ehdisp", /* name */
3716 OPTGROUP_NONE
, /* optinfo_flags */
3717 TV_TREE_EH
, /* tv_id */
3718 PROP_gimple_lcf
, /* properties_required */
3719 0, /* properties_provided */
3720 0, /* properties_destroyed */
3721 0, /* todo_flags_start */
3722 0, /* todo_flags_finish */
3725 class pass_lower_eh_dispatch
: public gimple_opt_pass
3728 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3729 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3732 /* opt_pass methods: */
3733 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3734 virtual unsigned int execute (function
*);
3736 }; // class pass_lower_eh_dispatch
3739 pass_lower_eh_dispatch::execute (function
*fun
)
3743 bool redirected
= false;
3745 assign_filter_values ();
3747 FOR_EACH_BB_FN (bb
, fun
)
3749 gimple last
= last_stmt (bb
);
3752 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3754 redirected
|= lower_eh_dispatch (bb
,
3755 as_a
<geh_dispatch
*> (last
));
3756 flags
|= TODO_update_ssa_only_virtuals
;
3758 else if (gimple_code (last
) == GIMPLE_RESX
)
3760 if (stmt_can_throw_external (last
))
3761 optimize_clobbers (bb
);
3763 flags
|= sink_clobbers (bb
);
3768 delete_unreachable_blocks ();
3775 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3777 return new pass_lower_eh_dispatch (ctxt
);
3780 /* Walk statements, see what regions and, optionally, landing pads
3781 are really referenced.
3783 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3784 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3786 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3789 The caller is responsible for freeing the returned sbitmaps. */
3792 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3794 sbitmap r_reachable
, lp_reachable
;
3796 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3797 gcc_checking_assert (r_reachablep
!= NULL
);
3799 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3800 bitmap_clear (r_reachable
);
3801 *r_reachablep
= r_reachable
;
3803 if (mark_landing_pads
)
3805 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
3806 bitmap_clear (lp_reachable
);
3807 *lp_reachablep
= lp_reachable
;
3810 lp_reachable
= NULL
;
3812 FOR_EACH_BB_FN (bb
, cfun
)
3814 gimple_stmt_iterator gsi
;
3816 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3818 gimple stmt
= gsi_stmt (gsi
);
3820 if (mark_landing_pads
)
3822 int lp_nr
= lookup_stmt_eh_lp (stmt
);
3824 /* Negative LP numbers are MUST_NOT_THROW regions which
3825 are not considered BB enders. */
3827 bitmap_set_bit (r_reachable
, -lp_nr
);
3829 /* Positive LP numbers are real landing pads, and BB enders. */
3832 gcc_assert (gsi_one_before_end_p (gsi
));
3833 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
3834 bitmap_set_bit (r_reachable
, region
->index
);
3835 bitmap_set_bit (lp_reachable
, lp_nr
);
3839 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3840 switch (gimple_code (stmt
))
3843 bitmap_set_bit (r_reachable
,
3844 gimple_resx_region (as_a
<gresx
*> (stmt
)));
3846 case GIMPLE_EH_DISPATCH
:
3847 bitmap_set_bit (r_reachable
,
3848 gimple_eh_dispatch_region (
3849 as_a
<geh_dispatch
*> (stmt
)));
3858 /* Remove unreachable handlers and unreachable landing pads. */
3861 remove_unreachable_handlers (void)
3863 sbitmap r_reachable
, lp_reachable
;
3868 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
3872 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3873 dump_eh_tree (dump_file
, cfun
);
3874 fprintf (dump_file
, "Reachable regions: ");
3875 dump_bitmap_file (dump_file
, r_reachable
);
3876 fprintf (dump_file
, "Reachable landing pads: ");
3877 dump_bitmap_file (dump_file
, lp_reachable
);
3882 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3883 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
3885 "Removing unreachable region %d\n",
3889 remove_unreachable_eh_regions (r_reachable
);
3891 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3892 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
3896 "Removing unreachable landing pad %d\n",
3898 remove_eh_landing_pad (lp
);
3903 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3904 dump_eh_tree (dump_file
, cfun
);
3905 fprintf (dump_file
, "\n\n");
3908 sbitmap_free (r_reachable
);
3909 sbitmap_free (lp_reachable
);
3911 #ifdef ENABLE_CHECKING
3912 verify_eh_tree (cfun
);
3916 /* Remove unreachable handlers if any landing pads have been removed after
3917 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3920 maybe_remove_unreachable_handlers (void)
3925 if (cfun
->eh
== NULL
)
3928 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3929 if (lp
&& lp
->post_landing_pad
)
3931 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3933 remove_unreachable_handlers ();
3939 /* Remove regions that do not have landing pads. This assumes
3940 that remove_unreachable_handlers has already been run, and
3941 that we've just manipulated the landing pads since then.
3943 Preserve regions with landing pads and regions that prevent
3944 exceptions from propagating further, even if these regions
3945 are not reachable. */
3948 remove_unreachable_handlers_no_lp (void)
3951 sbitmap r_reachable
;
3954 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
3956 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3961 if (region
->landing_pads
!= NULL
3962 || region
->type
== ERT_MUST_NOT_THROW
)
3963 bitmap_set_bit (r_reachable
, region
->index
);
3966 && !bitmap_bit_p (r_reachable
, region
->index
))
3968 "Removing unreachable region %d\n",
3972 remove_unreachable_eh_regions (r_reachable
);
3974 sbitmap_free (r_reachable
);
3977 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3978 optimisticaly split all sorts of edges, including EH edges. The
3979 optimization passes in between may not have needed them; if not,
3980 we should undo the split.
3982 Recognize this case by having one EH edge incoming to the BB and
3983 one normal edge outgoing; BB should be empty apart from the
3984 post_landing_pad label.
3986 Note that this is slightly different from the empty handler case
3987 handled by cleanup_empty_eh, in that the actual handler may yet
3988 have actual code but the landing pad has been separated from the
3989 handler. As such, cleanup_empty_eh relies on this transformation
3990 having been done first. */
3993 unsplit_eh (eh_landing_pad lp
)
3995 basic_block bb
= label_to_block (lp
->post_landing_pad
);
3996 gimple_stmt_iterator gsi
;
3999 /* Quickly check the edge counts on BB for singularity. */
4000 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4002 e_in
= single_pred_edge (bb
);
4003 e_out
= single_succ_edge (bb
);
4005 /* Input edge must be EH and output edge must be normal. */
4006 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4009 /* The block must be empty except for the labels and debug insns. */
4010 gsi
= gsi_after_labels (bb
);
4011 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4012 gsi_next_nondebug (&gsi
);
4013 if (!gsi_end_p (gsi
))
4016 /* The destination block must not already have a landing pad
4017 for a different region. */
4018 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4020 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4026 lab
= gimple_label_label (label_stmt
);
4027 lp_nr
= EH_LANDING_PAD_NR (lab
);
4028 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4032 /* The new destination block must not already be a destination of
4033 the source block, lest we merge fallthru and eh edges and get
4034 all sorts of confused. */
4035 if (find_edge (e_in
->src
, e_out
->dest
))
4038 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4039 thought this should have been cleaned up by a phicprop pass, but
4040 that doesn't appear to handle virtuals. Propagate by hand. */
4041 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4043 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4046 gphi
*phi
= gpi
.phi ();
4047 tree lhs
= gimple_phi_result (phi
);
4048 tree rhs
= gimple_phi_arg_def (phi
, 0);
4049 use_operand_p use_p
;
4050 imm_use_iterator iter
;
4052 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4054 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4055 SET_USE (use_p
, rhs
);
4058 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4059 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4061 remove_phi_node (&gpi
, true);
4065 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4066 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4067 lp
->index
, e_out
->dest
->index
);
4069 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4070 a successor edge, humor it. But do the real CFG change with the
4071 predecessor of E_OUT in order to preserve the ordering of arguments
4072 to the PHI nodes in E_OUT->DEST. */
4073 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4074 redirect_edge_pred (e_out
, e_in
->src
);
4075 e_out
->flags
= e_in
->flags
;
4076 e_out
->probability
= e_in
->probability
;
4077 e_out
->count
= e_in
->count
;
4083 /* Examine each landing pad block and see if it matches unsplit_eh. */
4086 unsplit_all_eh (void)
4088 bool changed
= false;
4092 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4094 changed
|= unsplit_eh (lp
);
4099 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4100 to OLD_BB to NEW_BB; return true on success, false on failure.
4102 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4103 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4104 Virtual PHIs may be deleted and marked for renaming. */
4107 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4108 edge old_bb_out
, bool change_region
)
4110 gphi_iterator ngsi
, ogsi
;
4113 bitmap ophi_handled
;
4115 /* The destination block must not be a regular successor for any
4116 of the preds of the landing pad. Thus, avoid turning
4126 which CFG verification would choke on. See PR45172 and PR51089. */
4127 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4128 if (find_edge (e
->src
, new_bb
))
4131 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4132 redirect_edge_var_map_clear (e
);
4134 ophi_handled
= BITMAP_ALLOC (NULL
);
4136 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4137 for the edges we're going to move. */
4138 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4140 gphi
*ophi
, *nphi
= ngsi
.phi ();
4143 nresult
= gimple_phi_result (nphi
);
4144 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4146 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4147 the source ssa_name. */
4149 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4152 if (gimple_phi_result (ophi
) == nop
)
4157 /* If we did find the corresponding PHI, copy those inputs. */
4160 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4161 if (!has_single_use (nop
))
4163 imm_use_iterator imm_iter
;
4164 use_operand_p use_p
;
4166 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4168 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4169 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4170 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4174 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4175 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4180 if ((e
->flags
& EDGE_EH
) == 0)
4182 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4183 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4184 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4187 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4188 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4189 variable is unchanged from input to the block and we can simply
4190 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4194 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4195 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4196 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4200 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4201 we don't know what values from the other edges into NEW_BB to use. */
4202 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4204 gphi
*ophi
= ogsi
.phi ();
4205 tree oresult
= gimple_phi_result (ophi
);
4206 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4210 /* Finally, move the edges and update the PHIs. */
4211 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4212 if (e
->flags
& EDGE_EH
)
4214 /* ??? CFG manipluation routines do not try to update loop
4215 form on edge redirection. Do so manually here for now. */
4216 /* If we redirect a loop entry or latch edge that will either create
4217 a multiple entry loop or rotate the loop. If the loops merge
4218 we may have created a loop with multiple latches.
4219 All of this isn't easily fixed thus cancel the affected loop
4220 and mark the other loop as possibly having multiple latches. */
4221 if (e
->dest
== e
->dest
->loop_father
->header
)
4223 mark_loop_for_removal (e
->dest
->loop_father
);
4224 new_bb
->loop_father
->latch
= NULL
;
4225 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4227 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4228 redirect_edge_succ (e
, new_bb
);
4229 flush_pending_stmts (e
);
4234 BITMAP_FREE (ophi_handled
);
4238 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4239 redirect_edge_var_map_clear (e
);
4240 BITMAP_FREE (ophi_handled
);
4244 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4245 old region to NEW_REGION at BB. */
4248 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4249 eh_landing_pad lp
, eh_region new_region
)
4251 gimple_stmt_iterator gsi
;
4254 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4258 lp
->region
= new_region
;
4259 lp
->next_lp
= new_region
->landing_pads
;
4260 new_region
->landing_pads
= lp
;
4262 /* Delete the RESX that was matched within the empty handler block. */
4263 gsi
= gsi_last_bb (bb
);
4264 unlink_stmt_vdef (gsi_stmt (gsi
));
4265 gsi_remove (&gsi
, true);
4267 /* Clean up E_OUT for the fallthru. */
4268 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4269 e_out
->probability
= REG_BR_PROB_BASE
;
4272 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4273 unsplitting than unsplit_eh was prepared to handle, e.g. when
4274 multiple incoming edges and phis are involved. */
4277 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4279 gimple_stmt_iterator gsi
;
4282 /* We really ought not have totally lost everything following
4283 a landing pad label. Given that BB is empty, there had better
4285 gcc_assert (e_out
!= NULL
);
4287 /* The destination block must not already have a landing pad
4288 for a different region. */
4290 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4292 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4297 lab
= gimple_label_label (stmt
);
4298 lp_nr
= EH_LANDING_PAD_NR (lab
);
4299 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4303 /* Attempt to move the PHIs into the successor block. */
4304 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4306 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4308 "Unsplit EH landing pad %d to block %i "
4309 "(via cleanup_empty_eh).\n",
4310 lp
->index
, e_out
->dest
->index
);
4317 /* Return true if edge E_FIRST is part of an empty infinite loop
4318 or leads to such a loop through a series of single successor
4322 infinite_empty_loop_p (edge e_first
)
4324 bool inf_loop
= false;
4327 if (e_first
->dest
== e_first
->src
)
4330 e_first
->src
->aux
= (void *) 1;
4331 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4333 gimple_stmt_iterator gsi
;
4339 e
->dest
->aux
= (void *) 1;
4340 gsi
= gsi_after_labels (e
->dest
);
4341 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4342 gsi_next_nondebug (&gsi
);
4343 if (!gsi_end_p (gsi
))
4346 e_first
->src
->aux
= NULL
;
4347 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4348 e
->dest
->aux
= NULL
;
4353 /* Examine the block associated with LP to determine if it's an empty
4354 handler for its EH region. If so, attempt to redirect EH edges to
4355 an outer region. Return true the CFG was updated in any way. This
4356 is similar to jump forwarding, just across EH edges. */
4359 cleanup_empty_eh (eh_landing_pad lp
)
4361 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4362 gimple_stmt_iterator gsi
;
4364 eh_region new_region
;
4367 bool has_non_eh_pred
;
4371 /* There can be zero or one edges out of BB. This is the quickest test. */
4372 switch (EDGE_COUNT (bb
->succs
))
4378 e_out
= single_succ_edge (bb
);
4384 resx
= last_stmt (bb
);
4385 if (resx
&& is_gimple_resx (resx
))
4387 if (stmt_can_throw_external (resx
))
4388 optimize_clobbers (bb
);
4389 else if (sink_clobbers (bb
))
4393 gsi
= gsi_after_labels (bb
);
4395 /* Make sure to skip debug statements. */
4396 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4397 gsi_next_nondebug (&gsi
);
4399 /* If the block is totally empty, look for more unsplitting cases. */
4400 if (gsi_end_p (gsi
))
4402 /* For the degenerate case of an infinite loop bail out.
4403 If bb has no successors and is totally empty, which can happen e.g.
4404 because of incorrect noreturn attribute, bail out too. */
4406 || infinite_empty_loop_p (e_out
))
4409 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4412 /* The block should consist only of a single RESX statement, modulo a
4413 preceding call to __builtin_stack_restore if there is no outgoing
4414 edge, since the call can be eliminated in this case. */
4415 resx
= gsi_stmt (gsi
);
4416 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4419 resx
= gsi_stmt (gsi
);
4421 if (!is_gimple_resx (resx
))
4423 gcc_assert (gsi_one_before_end_p (gsi
));
4425 /* Determine if there are non-EH edges, or resx edges into the handler. */
4426 has_non_eh_pred
= false;
4427 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4428 if (!(e
->flags
& EDGE_EH
))
4429 has_non_eh_pred
= true;
4431 /* Find the handler that's outer of the empty handler by looking at
4432 where the RESX instruction was vectored. */
4433 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4434 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4436 /* If there's no destination region within the current function,
4437 redirection is trivial via removing the throwing statements from
4438 the EH region, removing the EH edges, and allowing the block
4439 to go unreachable. */
4440 if (new_region
== NULL
)
4442 gcc_assert (e_out
== NULL
);
4443 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4444 if (e
->flags
& EDGE_EH
)
4446 gimple stmt
= last_stmt (e
->src
);
4447 remove_stmt_from_eh_lp (stmt
);
4455 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4456 to handle the abort and allow the blocks to go unreachable. */
4457 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4459 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4460 if (e
->flags
& EDGE_EH
)
4462 gimple stmt
= last_stmt (e
->src
);
4463 remove_stmt_from_eh_lp (stmt
);
4464 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4472 /* Try to redirect the EH edges and merge the PHIs into the destination
4473 landing pad block. If the merge succeeds, we'll already have redirected
4474 all the EH edges. The handler itself will go unreachable if there were
4476 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4479 /* Finally, if all input edges are EH edges, then we can (potentially)
4480 reduce the number of transfers from the runtime by moving the landing
4481 pad from the original region to the new region. This is a win when
4482 we remove the last CLEANUP region along a particular exception
4483 propagation path. Since nothing changes except for the region with
4484 which the landing pad is associated, the PHI nodes do not need to be
4486 if (!has_non_eh_pred
)
4488 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4489 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4490 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4491 lp
->index
, new_region
->index
);
4493 /* ??? The CFG didn't change, but we may have rendered the
4494 old EH region unreachable. Trigger a cleanup there. */
4501 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4502 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4503 remove_eh_landing_pad (lp
);
4507 /* Do a post-order traversal of the EH region tree. Examine each
4508 post_landing_pad block and see if we can eliminate it as empty. */
4511 cleanup_all_empty_eh (void)
4513 bool changed
= false;
4517 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4519 changed
|= cleanup_empty_eh (lp
);
4524 /* Perform cleanups and lowering of exception handling
4525 1) cleanups regions with handlers doing nothing are optimized out
4526 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4527 3) Info about regions that are containing instructions, and regions
4528 reachable via local EH edges is collected
4529 4) Eh tree is pruned for regions no longer necessary.
4531 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4532 Unify those that have the same failure decl and locus.
4536 execute_cleanup_eh_1 (void)
4538 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4539 looking up unreachable landing pads. */
4540 remove_unreachable_handlers ();
4542 /* Watch out for the region tree vanishing due to all unreachable. */
4543 if (cfun
->eh
->region_tree
)
4545 bool changed
= false;
4548 changed
|= unsplit_all_eh ();
4549 changed
|= cleanup_all_empty_eh ();
4553 free_dominance_info (CDI_DOMINATORS
);
4554 free_dominance_info (CDI_POST_DOMINATORS
);
4556 /* We delayed all basic block deletion, as we may have performed
4557 cleanups on EH edges while non-EH edges were still present. */
4558 delete_unreachable_blocks ();
4560 /* We manipulated the landing pads. Remove any region that no
4561 longer has a landing pad. */
4562 remove_unreachable_handlers_no_lp ();
4564 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4573 const pass_data pass_data_cleanup_eh
=
4575 GIMPLE_PASS
, /* type */
4576 "ehcleanup", /* name */
4577 OPTGROUP_NONE
, /* optinfo_flags */
4578 TV_TREE_EH
, /* tv_id */
4579 PROP_gimple_lcf
, /* properties_required */
4580 0, /* properties_provided */
4581 0, /* properties_destroyed */
4582 0, /* todo_flags_start */
4583 0, /* todo_flags_finish */
4586 class pass_cleanup_eh
: public gimple_opt_pass
4589 pass_cleanup_eh (gcc::context
*ctxt
)
4590 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4593 /* opt_pass methods: */
4594 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4595 virtual bool gate (function
*fun
)
4597 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4600 virtual unsigned int execute (function
*);
4602 }; // class pass_cleanup_eh
4605 pass_cleanup_eh::execute (function
*fun
)
4607 int ret
= execute_cleanup_eh_1 ();
4609 /* If the function no longer needs an EH personality routine
4610 clear it. This exposes cross-language inlining opportunities
4611 and avoids references to a never defined personality routine. */
4612 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4613 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4614 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4622 make_pass_cleanup_eh (gcc::context
*ctxt
)
4624 return new pass_cleanup_eh (ctxt
);
4627 /* Verify that BB containing STMT as the last statement, has precisely the
4628 edge that make_eh_edges would create. */
4631 verify_eh_edges (gimple stmt
)
4633 basic_block bb
= gimple_bb (stmt
);
4634 eh_landing_pad lp
= NULL
;
4639 lp_nr
= lookup_stmt_eh_lp (stmt
);
4641 lp
= get_eh_landing_pad_from_number (lp_nr
);
4644 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4646 if (e
->flags
& EDGE_EH
)
4650 error ("BB %i has multiple EH edges", bb
->index
);
4662 error ("BB %i can not throw but has an EH edge", bb
->index
);
4668 if (!stmt_could_throw_p (stmt
))
4670 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4674 if (eh_edge
== NULL
)
4676 error ("BB %i is missing an EH edge", bb
->index
);
4680 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4682 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4689 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4692 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4696 basic_block src
, dst
;
4697 bool want_fallthru
= true;
4701 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4702 src
= gimple_bb (stmt
);
4704 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4705 gcc_assert (e
->aux
== NULL
);
4710 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4712 dst
= label_to_block (c
->label
);
4713 e
= find_edge (src
, dst
);
4716 error ("BB %i is missing an edge", src
->index
);
4721 /* A catch-all handler doesn't have a fallthru. */
4722 if (c
->type_list
== NULL
)
4724 want_fallthru
= false;
4730 case ERT_ALLOWED_EXCEPTIONS
:
4731 dst
= label_to_block (r
->u
.allowed
.label
);
4732 e
= find_edge (src
, dst
);
4735 error ("BB %i is missing an edge", src
->index
);
4746 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4748 if (e
->flags
& EDGE_FALLTHRU
)
4750 if (fall_edge
!= NULL
)
4752 error ("BB %i too many fallthru edges", src
->index
);
4761 error ("BB %i has incorrect edge", src
->index
);
4765 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4767 error ("BB %i has incorrect fallthru edge", src
->index
);