1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2020 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"
28 #include "tree-pass.h"
31 #include "diagnostic-core.h"
32 #include "fold-const.h"
36 #include "cfgcleanup.h"
38 #include "gimple-iterator.h"
40 #include "tree-into-ssa.h"
42 #include "tree-inline.h"
43 #include "langhooks.h"
45 #include "gimple-low.h"
46 #include "stringpool.h"
51 /* In some instances a tree and a gimple need to be stored in a same table,
52 i.e. in hash tables. This is a structure to do this. */
53 typedef union {tree
*tp
; tree t
; gimple
*g
;} treemple
;
55 /* Misc functions used in this file. */
57 /* Remember and lookup EH landing pad data for arbitrary statements.
58 Really this means any statement that could_throw_p. We could
59 stuff this information into the stmt_ann data structure, but:
61 (1) We absolutely rely on this information being kept until
62 we get to rtl. Once we're done with lowering here, if we lose
63 the information there's no way to recover it!
65 (2) There are many more statements that *cannot* throw as
66 compared to those that can. We should be saving some amount
67 of space by only allocating memory for those that can throw. */
69 /* Add statement T in function IFUN to landing pad NUM. */
72 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple
*t
, int num
)
74 gcc_assert (num
!= 0);
76 if (!get_eh_throw_stmt_table (ifun
))
77 set_eh_throw_stmt_table (ifun
, hash_map
<gimple
*, int>::create_ggc (31));
79 gcc_assert (!get_eh_throw_stmt_table (ifun
)->put (t
, num
));
82 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
85 add_stmt_to_eh_lp (gimple
*t
, int num
)
87 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
90 /* Add statement T to the single EH landing pad in REGION. */
93 record_stmt_eh_region (eh_region region
, gimple
*t
)
97 if (region
->type
== ERT_MUST_NOT_THROW
)
98 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
101 eh_landing_pad lp
= region
->landing_pads
;
103 lp
= gen_eh_landing_pad (region
);
105 gcc_assert (lp
->next_lp
== NULL
);
106 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
111 /* Remove statement T in function IFUN from its EH landing pad. */
114 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple
*t
)
116 if (!get_eh_throw_stmt_table (ifun
))
119 if (!get_eh_throw_stmt_table (ifun
)->get (t
))
122 get_eh_throw_stmt_table (ifun
)->remove (t
);
127 /* Remove statement T in the current function (cfun) from its
131 remove_stmt_from_eh_lp (gimple
*t
)
133 return remove_stmt_from_eh_lp_fn (cfun
, t
);
136 /* Determine if statement T is inside an EH region in function IFUN.
137 Positive numbers indicate a landing pad index; negative numbers
138 indicate a MUST_NOT_THROW region index; zero indicates that the
139 statement is not recorded in the region table. */
142 lookup_stmt_eh_lp_fn (struct function
*ifun
, const gimple
*t
)
144 if (ifun
->eh
->throw_stmt_table
== NULL
)
147 int *lp_nr
= ifun
->eh
->throw_stmt_table
->get (const_cast <gimple
*> (t
));
148 return lp_nr
? *lp_nr
: 0;
151 /* Likewise, but always use the current function. */
154 lookup_stmt_eh_lp (const gimple
*t
)
156 /* We can get called from initialized data when -fnon-call-exceptions
157 is on; prevent crash. */
160 return lookup_stmt_eh_lp_fn (cfun
, t
);
163 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
164 nodes and LABEL_DECL nodes. We will use this during the second phase to
165 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
167 struct finally_tree_node
169 /* When storing a GIMPLE_TRY, we have to record a gimple. However
170 when deciding whether a GOTO to a certain LABEL_DECL (which is a
171 tree) leaves the TRY block, its necessary to record a tree in
172 this field. Thus a treemple is used. */
177 /* Hashtable helpers. */
179 struct finally_tree_hasher
: free_ptr_hash
<finally_tree_node
>
181 static inline hashval_t
hash (const finally_tree_node
*);
182 static inline bool equal (const finally_tree_node
*,
183 const finally_tree_node
*);
187 finally_tree_hasher::hash (const finally_tree_node
*v
)
189 return (intptr_t)v
->child
.t
>> 4;
193 finally_tree_hasher::equal (const finally_tree_node
*v
,
194 const finally_tree_node
*c
)
196 return v
->child
.t
== c
->child
.t
;
199 /* Note that this table is *not* marked GTY. It is short-lived. */
200 static hash_table
<finally_tree_hasher
> *finally_tree
;
203 record_in_finally_tree (treemple child
, gtry
*parent
)
205 struct finally_tree_node
*n
;
206 finally_tree_node
**slot
;
208 n
= XNEW (struct finally_tree_node
);
212 slot
= finally_tree
->find_slot (n
, INSERT
);
218 collect_finally_tree (gimple
*stmt
, gtry
*region
);
220 /* Go through the gimple sequence. Works with collect_finally_tree to
221 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
224 collect_finally_tree_1 (gimple_seq seq
, gtry
*region
)
226 gimple_stmt_iterator gsi
;
228 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
229 collect_finally_tree (gsi_stmt (gsi
), region
);
233 collect_finally_tree (gimple
*stmt
, gtry
*region
)
237 switch (gimple_code (stmt
))
240 temp
.t
= gimple_label_label (as_a
<glabel
*> (stmt
));
241 record_in_finally_tree (temp
, region
);
245 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
248 record_in_finally_tree (temp
, region
);
249 collect_finally_tree_1 (gimple_try_eval (stmt
),
250 as_a
<gtry
*> (stmt
));
251 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
253 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
255 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
256 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
261 collect_finally_tree_1 (gimple_catch_handler (
262 as_a
<gcatch
*> (stmt
)),
266 case GIMPLE_EH_FILTER
:
267 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
272 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
273 collect_finally_tree_1 (gimple_eh_else_n_body (eh_else_stmt
), region
);
274 collect_finally_tree_1 (gimple_eh_else_e_body (eh_else_stmt
), region
);
279 /* A type, a decl, or some kind of statement that we're not
280 interested in. Don't walk them. */
286 /* Use the finally tree to determine if a jump from START to TARGET
287 would leave the try_finally node that START lives in. */
290 outside_finally_tree (treemple start
, gimple
*target
)
292 struct finally_tree_node n
, *p
;
297 p
= finally_tree
->find (&n
);
302 while (start
.g
!= target
);
307 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
308 nodes into a set of gotos, magic labels, and eh regions.
309 The eh region creation is straight-forward, but frobbing all the gotos
310 and such into shape isn't. */
312 /* The sequence into which we record all EH stuff. This will be
313 placed at the end of the function when we're all done. */
314 static gimple_seq eh_seq
;
316 /* Record whether an EH region contains something that can throw,
317 indexed by EH region number. */
318 static bitmap eh_region_may_contain_throw_map
;
320 /* The GOTO_QUEUE is an array of GIMPLE_GOTO and GIMPLE_RETURN
321 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
322 The idea is to record a gimple statement for everything except for
323 the conditionals, which get their labels recorded. Since labels are
324 of type 'tree', we need this node to store both gimple and tree
325 objects. REPL_STMT is the sequence used to replace the goto/return
326 statement. CONT_STMT is used to store the statement that allows
327 the return/goto to jump to the original destination. */
329 struct goto_queue_node
333 gimple_seq repl_stmt
;
336 /* This is used when index >= 0 to indicate that stmt is a label (as
337 opposed to a goto stmt). */
341 /* State of the world while lowering. */
345 /* What's "current" while constructing the eh region tree. These
346 correspond to variables of the same name in cfun->eh, which we
347 don't have easy access to. */
348 eh_region cur_region
;
350 /* What's "current" for the purposes of __builtin_eh_pointer. For
351 a CATCH, this is the associated TRY. For an EH_FILTER, this is
352 the associated ALLOWED_EXCEPTIONS, etc. */
353 eh_region ehp_region
;
355 /* Processing of TRY_FINALLY requires a bit more state. This is
356 split out into a separate structure so that we don't have to
357 copy so much when processing other nodes. */
358 struct leh_tf_state
*tf
;
360 /* Outer non-clean up region. */
361 eh_region outer_non_cleanup
;
366 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
367 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
368 this so that outside_finally_tree can reliably reference the tree used
369 in the collect_finally_tree data structures. */
370 gtry
*try_finally_expr
;
373 /* While lowering a top_p usually it is expanded into multiple statements,
374 thus we need the following field to store them. */
375 gimple_seq top_p_seq
;
377 /* The state outside this try_finally node. */
378 struct leh_state
*outer
;
380 /* The exception region created for it. */
383 /* The goto queue. */
384 struct goto_queue_node
*goto_queue
;
385 size_t goto_queue_size
;
386 size_t goto_queue_active
;
388 /* Pointer map to help in searching goto_queue when it is large. */
389 hash_map
<gimple
*, goto_queue_node
*> *goto_queue_map
;
391 /* The set of unique labels seen as entries in the goto queue. */
392 vec
<tree
> dest_array
;
394 /* A label to be added at the end of the completed transformed
395 sequence. It will be set if may_fallthru was true *at one time*,
396 though subsequent transformations may have cleared that flag. */
399 /* True if it is possible to fall out the bottom of the try block.
400 Cleared if the fallthru is converted to a goto. */
403 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
406 /* True if the finally block can receive an exception edge.
407 Cleared if the exception case is handled by code duplication. */
411 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gtry
*);
413 /* Search for STMT in the goto queue. Return the replacement,
414 or null if the statement isn't in the queue. */
416 #define LARGE_GOTO_QUEUE 20
418 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
421 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
425 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
427 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
428 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
429 return tf
->goto_queue
[i
].repl_stmt
;
433 /* If we have a large number of entries in the goto_queue, create a
434 pointer map and use that for searching. */
436 if (!tf
->goto_queue_map
)
438 tf
->goto_queue_map
= new hash_map
<gimple
*, goto_queue_node
*>;
439 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
441 bool existed
= tf
->goto_queue_map
->put (tf
->goto_queue
[i
].stmt
.g
,
443 gcc_assert (!existed
);
447 goto_queue_node
**slot
= tf
->goto_queue_map
->get (stmt
.g
);
449 return ((*slot
)->repl_stmt
);
454 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
455 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
456 then we can just splat it in, otherwise we add the new stmts immediately
457 after the GIMPLE_COND and redirect. */
460 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
461 gimple_stmt_iterator
*gsi
)
466 location_t loc
= gimple_location (gsi_stmt (*gsi
));
469 new_seq
= find_goto_replacement (tf
, temp
);
473 if (gimple_seq_singleton_p (new_seq
)
474 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
476 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
480 label
= create_artificial_label (loc
);
481 /* Set the new label for the GIMPLE_COND */
484 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
485 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
488 /* The real work of replace_goto_queue. Returns with TSI updated to
489 point to the next statement. */
491 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
494 replace_goto_queue_1 (gimple
*stmt
, struct leh_tf_state
*tf
,
495 gimple_stmt_iterator
*gsi
)
501 switch (gimple_code (stmt
))
506 seq
= find_goto_replacement (tf
, temp
);
509 gimple_stmt_iterator i
;
510 seq
= gimple_seq_copy (seq
);
511 for (i
= gsi_start (seq
); !gsi_end_p (i
); gsi_next (&i
))
512 gimple_set_location (gsi_stmt (i
), gimple_location (stmt
));
513 gsi_insert_seq_before (gsi
, seq
, GSI_SAME_STMT
);
514 gsi_remove (gsi
, false);
520 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
521 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
525 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
526 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
529 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (
530 as_a
<gcatch
*> (stmt
)),
533 case GIMPLE_EH_FILTER
:
534 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
538 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
539 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (eh_else_stmt
),
541 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (eh_else_stmt
),
547 /* These won't have gotos in them. */
554 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
557 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
559 gimple_stmt_iterator gsi
= gsi_start (*seq
);
561 while (!gsi_end_p (gsi
))
562 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
565 /* Replace all goto queue members. */
568 replace_goto_queue (struct leh_tf_state
*tf
)
570 if (tf
->goto_queue_active
== 0)
572 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
573 replace_goto_queue_stmt_list (&eh_seq
, tf
);
576 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
577 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
581 record_in_goto_queue (struct leh_tf_state
*tf
,
588 struct goto_queue_node
*q
;
590 gcc_assert (!tf
->goto_queue_map
);
592 active
= tf
->goto_queue_active
;
593 size
= tf
->goto_queue_size
;
596 size
= (size
? size
* 2 : 32);
597 tf
->goto_queue_size
= size
;
599 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
602 q
= &tf
->goto_queue
[active
];
603 tf
->goto_queue_active
= active
+ 1;
605 memset (q
, 0, sizeof (*q
));
608 q
->location
= location
;
609 q
->is_label
= is_label
;
612 /* Record the LABEL label in the goto queue contained in TF.
616 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
620 treemple temp
, new_stmt
;
625 /* Computed and non-local gotos do not get processed. Given
626 their nature we can neither tell whether we've escaped the
627 finally block nor redirect them if we knew. */
628 if (TREE_CODE (label
) != LABEL_DECL
)
631 /* No need to record gotos that don't leave the try block. */
633 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
636 if (! tf
->dest_array
.exists ())
638 tf
->dest_array
.create (10);
639 tf
->dest_array
.quick_push (label
);
644 int n
= tf
->dest_array
.length ();
645 for (index
= 0; index
< n
; ++index
)
646 if (tf
->dest_array
[index
] == label
)
649 tf
->dest_array
.safe_push (label
);
652 /* In the case of a GOTO we want to record the destination label,
653 since with a GIMPLE_COND we have an easy access to the then/else
656 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
659 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
660 node, and if so record that fact in the goto queue associated with that
664 maybe_record_in_goto_queue (struct leh_state
*state
, gimple
*stmt
)
666 struct leh_tf_state
*tf
= state
->tf
;
672 switch (gimple_code (stmt
))
676 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
677 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 2);
678 record_in_goto_queue_label (tf
, new_stmt
,
679 gimple_cond_true_label (cond_stmt
),
680 EXPR_LOCATION (*new_stmt
.tp
));
681 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 3);
682 record_in_goto_queue_label (tf
, new_stmt
,
683 gimple_cond_false_label (cond_stmt
),
684 EXPR_LOCATION (*new_stmt
.tp
));
689 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
690 gimple_location (stmt
));
694 tf
->may_return
= true;
696 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
706 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
707 was in fact structured, and we've not yet done jump threading, then none
708 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
711 verify_norecord_switch_expr (struct leh_state
*state
,
712 gswitch
*switch_expr
)
714 struct leh_tf_state
*tf
= state
->tf
;
720 n
= gimple_switch_num_labels (switch_expr
);
722 for (i
= 0; i
< n
; ++i
)
725 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
727 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
731 #define verify_norecord_switch_expr(state, switch_expr)
734 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
735 non-null, insert it before the new branch. */
738 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
742 /* In the case of a return, the queue node must be a gimple statement. */
743 gcc_assert (!q
->is_label
);
745 /* Note that the return value may have already been computed, e.g.,
758 should return 0, not 1. We don't have to do anything to make
759 this happens because the return value has been placed in the
760 RESULT_DECL already. */
762 q
->cont_stmt
= q
->stmt
.g
;
765 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
767 x
= gimple_build_goto (finlab
);
768 gimple_set_location (x
, q
->location
);
769 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
772 /* Similar, but easier, for GIMPLE_GOTO. */
775 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
776 struct leh_tf_state
*tf
)
780 gcc_assert (q
->is_label
);
782 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
785 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
787 x
= gimple_build_goto (finlab
);
788 gimple_set_location (x
, q
->location
);
789 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
792 /* Emit a standard landing pad sequence into SEQ for REGION. */
795 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
797 eh_landing_pad lp
= region
->landing_pads
;
801 lp
= gen_eh_landing_pad (region
);
803 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
804 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
806 x
= gimple_build_label (lp
->post_landing_pad
);
807 gimple_seq_add_stmt (seq
, x
);
810 /* Emit a RESX statement into SEQ for REGION. */
813 emit_resx (gimple_seq
*seq
, eh_region region
)
815 gresx
*x
= gimple_build_resx (region
->index
);
816 gimple_seq_add_stmt (seq
, x
);
818 record_stmt_eh_region (region
->outer
, x
);
821 /* Note that the current EH region may contain a throw, or a
822 call to a function which itself may contain a throw. */
825 note_eh_region_may_contain_throw (eh_region region
)
827 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
829 if (region
->type
== ERT_MUST_NOT_THROW
)
831 region
= region
->outer
;
837 /* Check if REGION has been marked as containing a throw. If REGION is
838 NULL, this predicate is false. */
841 eh_region_may_contain_throw (eh_region r
)
843 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
846 /* We want to transform
847 try { body; } catch { stuff; }
857 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
858 should be placed before the second operand, or NULL. OVER is
859 an existing label that should be put at the exit, or NULL. */
862 frob_into_branch_around (gtry
*tp
, eh_region region
, tree over
)
865 gimple_seq cleanup
, result
;
866 location_t loc
= gimple_location (tp
);
868 cleanup
= gimple_try_cleanup (tp
);
869 result
= gimple_try_eval (tp
);
872 emit_post_landing_pad (&eh_seq
, region
);
874 if (gimple_seq_may_fallthru (cleanup
))
877 over
= create_artificial_label (loc
);
878 x
= gimple_build_goto (over
);
879 gimple_set_location (x
, loc
);
880 gimple_seq_add_stmt (&cleanup
, x
);
882 gimple_seq_add_seq (&eh_seq
, cleanup
);
886 x
= gimple_build_label (over
);
887 gimple_seq_add_stmt (&result
, x
);
892 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
893 Make sure to record all new labels found. */
896 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
901 gimple_stmt_iterator gsi
;
903 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
905 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
907 gimple
*stmt
= gsi_stmt (gsi
);
908 /* We duplicate __builtin_stack_restore at -O0 in the hope of eliminating
909 it on the EH paths. When it is not eliminated, make it transparent in
911 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
912 gimple_set_location (stmt
, UNKNOWN_LOCATION
);
913 else if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
915 tree block
= gimple_block (stmt
);
916 gimple_set_location (stmt
, loc
);
917 gimple_set_block (stmt
, block
);
922 region
= outer_state
->tf
->try_finally_expr
;
923 collect_finally_tree_1 (new_seq
, region
);
928 /* A subroutine of lower_try_finally. Create a fallthru label for
929 the given try_finally state. The only tricky bit here is that
930 we have to make sure to record the label in our outer context. */
933 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
935 tree label
= tf
->fallthru_label
;
940 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
941 tf
->fallthru_label
= label
;
945 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
951 /* A subroutine of lower_try_finally. If FINALLY consits of a
952 GIMPLE_EH_ELSE node, return it. */
954 static inline geh_else
*
955 get_eh_else (gimple_seq finally
)
957 gimple
*x
= gimple_seq_first_stmt (finally
);
958 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
960 gcc_assert (gimple_seq_singleton_p (finally
));
961 return as_a
<geh_else
*> (x
);
966 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
967 langhook returns non-null, then the language requires that the exception
968 path out of a try_finally be treated specially. To wit: the code within
969 the finally block may not itself throw an exception. We have two choices
970 here. First we can duplicate the finally block and wrap it in a
971 must_not_throw region. Second, we can generate code like
976 if (fintmp == eh_edge)
977 protect_cleanup_actions;
980 where "fintmp" is the temporary used in the switch statement generation
981 alternative considered below. For the nonce, we always choose the first
984 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
987 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
988 struct leh_state
*this_state
,
989 struct leh_tf_state
*tf
)
991 gimple_seq finally
= gimple_try_cleanup (tf
->top_p
);
993 /* EH_ELSE doesn't come from user code; only compiler generated stuff.
994 It does need to be handled here, so as to separate the (different)
995 EH path from the normal path. But we should not attempt to wrap
996 it with a must-not-throw node (which indeed gets in the way). */
997 if (geh_else
*eh_else
= get_eh_else (finally
))
999 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
1000 finally
= gimple_eh_else_e_body (eh_else
);
1002 /* Let the ELSE see the exception that's being processed, but
1003 since the cleanup is outside the try block, process it with
1004 outer_state, otherwise it may be used as a cleanup for
1005 itself, and Bad Things (TM) ensue. */
1006 eh_region save_ehp
= outer_state
->ehp_region
;
1007 outer_state
->ehp_region
= this_state
->cur_region
;
1008 lower_eh_constructs_1 (outer_state
, &finally
);
1009 outer_state
->ehp_region
= save_ehp
;
1013 /* First check for nothing to do. */
1014 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1016 tree actions
= lang_hooks
.eh_protect_cleanup_actions ();
1017 if (actions
== NULL
)
1021 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1022 gimple_location (tf
->try_finally_expr
));
1024 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1025 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1026 to be in an enclosing scope, but needs to be implemented at this level
1027 to avoid a nesting violation (see wrap_temporary_cleanups in
1028 cp/decl.c). Since it's logically at an outer level, we should call
1029 terminate before we get to it, so strip it away before adding the
1030 MUST_NOT_THROW filter. */
1031 gimple_stmt_iterator gsi
= gsi_start (finally
);
1032 gimple
*x
= gsi_stmt (gsi
);
1033 if (gimple_code (x
) == GIMPLE_TRY
1034 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1035 && gimple_try_catch_is_cleanup (x
))
1037 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1038 gsi_remove (&gsi
, false);
1041 /* Wrap the block with protect_cleanup_actions as the action. */
1042 geh_mnt
*eh_mnt
= gimple_build_eh_must_not_throw (actions
);
1043 gtry
*try_stmt
= gimple_build_try (finally
,
1044 gimple_seq_alloc_with_stmt (eh_mnt
),
1046 finally
= lower_eh_must_not_throw (outer_state
, try_stmt
);
1049 /* Drop all of this into the exception sequence. */
1050 emit_post_landing_pad (&eh_seq
, tf
->region
);
1051 gimple_seq_add_seq (&eh_seq
, finally
);
1052 if (gimple_seq_may_fallthru (finally
))
1053 emit_resx (&eh_seq
, tf
->region
);
1055 /* Having now been handled, EH isn't to be considered with
1056 the rest of the outgoing edges. */
1057 tf
->may_throw
= false;
1060 /* A subroutine of lower_try_finally. We have determined that there is
1061 no fallthru edge out of the finally block. This means that there is
1062 no outgoing edge corresponding to any incoming edge. Restructure the
1063 try_finally node for this special case. */
1066 lower_try_finally_nofallthru (struct leh_state
*state
,
1067 struct leh_tf_state
*tf
)
1073 struct goto_queue_node
*q
, *qe
;
1075 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1077 /* We expect that tf->top_p is a GIMPLE_TRY. */
1078 finally
= gimple_try_cleanup (tf
->top_p
);
1079 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1081 x
= gimple_build_label (lab
);
1082 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1085 qe
= q
+ tf
->goto_queue_active
;
1088 do_return_redirection (q
, lab
, NULL
);
1090 do_goto_redirection (q
, lab
, NULL
, tf
);
1092 replace_goto_queue (tf
);
1094 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1095 eh_else
= get_eh_else (finally
);
1098 finally
= gimple_eh_else_n_body (eh_else
);
1099 lower_eh_constructs_1 (state
, &finally
);
1100 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1104 finally
= gimple_eh_else_e_body (eh_else
);
1105 lower_eh_constructs_1 (state
, &finally
);
1107 emit_post_landing_pad (&eh_seq
, tf
->region
);
1108 gimple_seq_add_seq (&eh_seq
, finally
);
1113 lower_eh_constructs_1 (state
, &finally
);
1114 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1118 emit_post_landing_pad (&eh_seq
, tf
->region
);
1120 x
= gimple_build_goto (lab
);
1121 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1122 gimple_seq_add_stmt (&eh_seq
, x
);
1127 /* A subroutine of lower_try_finally. We have determined that there is
1128 exactly one destination of the finally block. Restructure the
1129 try_finally node for this special case. */
1132 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1134 struct goto_queue_node
*q
, *qe
;
1139 gimple_stmt_iterator gsi
;
1141 location_t loc
= gimple_location (tf
->try_finally_expr
);
1143 finally
= gimple_try_cleanup (tf
->top_p
);
1144 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1146 /* Since there's only one destination, and the destination edge can only
1147 either be EH or non-EH, that implies that all of our incoming edges
1148 are of the same type. Therefore we can lower EH_ELSE immediately. */
1149 eh_else
= get_eh_else (finally
);
1153 finally
= gimple_eh_else_e_body (eh_else
);
1155 finally
= gimple_eh_else_n_body (eh_else
);
1158 lower_eh_constructs_1 (state
, &finally
);
1160 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1162 gimple
*stmt
= gsi_stmt (gsi
);
1163 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1165 tree block
= gimple_block (stmt
);
1166 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1167 gimple_set_block (stmt
, block
);
1173 /* Only reachable via the exception edge. Add the given label to
1174 the head of the FINALLY block. Append a RESX at the end. */
1175 emit_post_landing_pad (&eh_seq
, tf
->region
);
1176 gimple_seq_add_seq (&eh_seq
, finally
);
1177 emit_resx (&eh_seq
, tf
->region
);
1181 if (tf
->may_fallthru
)
1183 /* Only reachable via the fallthru edge. Do nothing but let
1184 the two blocks run together; we'll fall out the bottom. */
1185 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1189 finally_label
= create_artificial_label (loc
);
1190 label_stmt
= gimple_build_label (finally_label
);
1191 gimple_seq_add_stmt (&tf
->top_p_seq
, label_stmt
);
1193 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1196 qe
= q
+ tf
->goto_queue_active
;
1200 /* Reachable by return expressions only. Redirect them. */
1202 do_return_redirection (q
, finally_label
, NULL
);
1203 replace_goto_queue (tf
);
1207 /* Reachable by goto expressions only. Redirect them. */
1209 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1210 replace_goto_queue (tf
);
1212 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1214 /* Reachable by goto to fallthru label only. Redirect it
1215 to the new label (already created, sadly), and do not
1216 emit the final branch out, or the fallthru label. */
1217 tf
->fallthru_label
= NULL
;
1222 /* Place the original return/goto to the original destination
1223 immediately after the finally block. */
1224 x
= tf
->goto_queue
[0].cont_stmt
;
1225 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1226 maybe_record_in_goto_queue (state
, x
);
1229 /* A subroutine of lower_try_finally. There are multiple edges incoming
1230 and outgoing from the finally block. Implement this by duplicating the
1231 finally block for every destination. */
1234 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1237 gimple_seq new_stmt
;
1242 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1244 finally
= gimple_try_cleanup (tf
->top_p
);
1246 /* Notice EH_ELSE, and simplify some of the remaining code
1247 by considering FINALLY to be the normal return path only. */
1248 eh_else
= get_eh_else (finally
);
1250 finally
= gimple_eh_else_n_body (eh_else
);
1252 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1255 if (tf
->may_fallthru
)
1257 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1258 lower_eh_constructs_1 (state
, &seq
);
1259 gimple_seq_add_seq (&new_stmt
, seq
);
1261 tmp
= lower_try_finally_fallthru_label (tf
);
1262 x
= gimple_build_goto (tmp
);
1263 gimple_set_location (x
, tf_loc
);
1264 gimple_seq_add_stmt (&new_stmt
, x
);
1269 /* We don't need to copy the EH path of EH_ELSE,
1270 since it is only emitted once. */
1272 seq
= gimple_eh_else_e_body (eh_else
);
1274 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1275 lower_eh_constructs_1 (state
, &seq
);
1277 emit_post_landing_pad (&eh_seq
, tf
->region
);
1278 gimple_seq_add_seq (&eh_seq
, seq
);
1279 emit_resx (&eh_seq
, tf
->region
);
1284 struct goto_queue_node
*q
, *qe
;
1285 int return_index
, index
;
1288 struct goto_queue_node
*q
;
1292 return_index
= tf
->dest_array
.length ();
1293 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1296 qe
= q
+ tf
->goto_queue_active
;
1299 index
= q
->index
< 0 ? return_index
: q
->index
;
1301 if (!labels
[index
].q
)
1302 labels
[index
].q
= q
;
1305 for (index
= 0; index
< return_index
+ 1; index
++)
1309 q
= labels
[index
].q
;
1313 lab
= labels
[index
].label
1314 = create_artificial_label (tf_loc
);
1316 if (index
== return_index
)
1317 do_return_redirection (q
, lab
, NULL
);
1319 do_goto_redirection (q
, lab
, NULL
, tf
);
1321 x
= gimple_build_label (lab
);
1322 gimple_seq_add_stmt (&new_stmt
, x
);
1324 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1325 lower_eh_constructs_1 (state
, &seq
);
1326 gimple_seq_add_seq (&new_stmt
, seq
);
1328 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1329 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1332 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1336 index
= q
->index
< 0 ? return_index
: q
->index
;
1338 if (labels
[index
].q
== q
)
1341 lab
= labels
[index
].label
;
1343 if (index
== return_index
)
1344 do_return_redirection (q
, lab
, NULL
);
1346 do_goto_redirection (q
, lab
, NULL
, tf
);
1349 replace_goto_queue (tf
);
1353 /* Need to link new stmts after running replace_goto_queue due
1354 to not wanting to process the same goto stmts twice. */
1355 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1358 /* A subroutine of lower_try_finally. There are multiple edges incoming
1359 and outgoing from the finally block. Implement this by instrumenting
1360 each incoming edge and creating a switch statement at the end of the
1361 finally block that branches to the appropriate destination. */
1364 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1366 struct goto_queue_node
*q
, *qe
;
1367 tree finally_tmp
, finally_label
;
1368 int return_index
, eh_index
, fallthru_index
;
1369 int nlabels
, ndests
, j
, last_case_index
;
1371 auto_vec
<tree
> case_label_vec
;
1372 gimple_seq switch_body
= NULL
;
1376 gimple
*switch_stmt
;
1378 hash_map
<tree
, gimple
*> *cont_map
= NULL
;
1379 /* The location of the TRY_FINALLY stmt. */
1380 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1381 /* The location of the finally block. */
1382 location_t finally_loc
;
1384 finally
= gimple_try_cleanup (tf
->top_p
);
1385 eh_else
= get_eh_else (finally
);
1387 /* Mash the TRY block to the head of the chain. */
1388 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1390 /* The location of the finally is either the last stmt in the finally
1391 block or the location of the TRY_FINALLY itself. */
1392 x
= gimple_seq_last_stmt (finally
);
1393 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1395 /* Prepare for switch statement generation. */
1396 nlabels
= tf
->dest_array
.length ();
1397 return_index
= nlabels
;
1398 eh_index
= return_index
+ tf
->may_return
;
1399 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1400 ndests
= fallthru_index
+ tf
->may_fallthru
;
1402 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1403 finally_label
= create_artificial_label (finally_loc
);
1405 /* We use vec::quick_push on case_label_vec throughout this function,
1406 since we know the size in advance and allocate precisely as muce
1408 case_label_vec
.create (ndests
);
1410 last_case_index
= 0;
1412 /* Begin inserting code for getting to the finally block. Things
1413 are done in this order to correspond to the sequence the code is
1416 if (tf
->may_fallthru
)
1418 x
= gimple_build_assign (finally_tmp
,
1419 build_int_cst (integer_type_node
,
1421 gimple_set_location (x
, finally_loc
);
1422 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1424 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1425 last_case
= build_case_label (tmp
, NULL
,
1426 create_artificial_label (finally_loc
));
1427 case_label_vec
.quick_push (last_case
);
1430 x
= gimple_build_label (CASE_LABEL (last_case
));
1431 gimple_seq_add_stmt (&switch_body
, x
);
1433 tmp
= lower_try_finally_fallthru_label (tf
);
1434 x
= gimple_build_goto (tmp
);
1435 gimple_set_location (x
, finally_loc
);
1436 gimple_seq_add_stmt (&switch_body
, x
);
1439 /* For EH_ELSE, emit the exception path (plus resx) now, then
1440 subsequently we only need consider the normal path. */
1445 finally
= gimple_eh_else_e_body (eh_else
);
1446 lower_eh_constructs_1 (state
, &finally
);
1448 emit_post_landing_pad (&eh_seq
, tf
->region
);
1449 gimple_seq_add_seq (&eh_seq
, finally
);
1450 emit_resx (&eh_seq
, tf
->region
);
1453 finally
= gimple_eh_else_n_body (eh_else
);
1455 else if (tf
->may_throw
)
1457 emit_post_landing_pad (&eh_seq
, tf
->region
);
1459 x
= gimple_build_assign (finally_tmp
,
1460 build_int_cst (integer_type_node
, eh_index
));
1461 gimple_seq_add_stmt (&eh_seq
, x
);
1463 x
= gimple_build_goto (finally_label
);
1464 gimple_set_location (x
, tf_loc
);
1465 gimple_seq_add_stmt (&eh_seq
, x
);
1467 tmp
= build_int_cst (integer_type_node
, eh_index
);
1468 last_case
= build_case_label (tmp
, NULL
,
1469 create_artificial_label (tf_loc
));
1470 case_label_vec
.quick_push (last_case
);
1473 x
= gimple_build_label (CASE_LABEL (last_case
));
1474 gimple_seq_add_stmt (&eh_seq
, x
);
1475 emit_resx (&eh_seq
, tf
->region
);
1478 x
= gimple_build_label (finally_label
);
1479 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1481 lower_eh_constructs_1 (state
, &finally
);
1482 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1484 /* Redirect each incoming goto edge. */
1486 qe
= q
+ tf
->goto_queue_active
;
1487 j
= last_case_index
+ tf
->may_return
;
1488 /* Prepare the assignments to finally_tmp that are executed upon the
1489 entrance through a particular edge. */
1492 gimple_seq mod
= NULL
;
1494 unsigned int case_index
;
1498 x
= gimple_build_assign (finally_tmp
,
1499 build_int_cst (integer_type_node
,
1501 gimple_seq_add_stmt (&mod
, x
);
1502 do_return_redirection (q
, finally_label
, mod
);
1503 switch_id
= return_index
;
1507 x
= gimple_build_assign (finally_tmp
,
1508 build_int_cst (integer_type_node
, q
->index
));
1509 gimple_seq_add_stmt (&mod
, x
);
1510 do_goto_redirection (q
, finally_label
, mod
, tf
);
1511 switch_id
= q
->index
;
1514 case_index
= j
+ q
->index
;
1515 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1518 tmp
= build_int_cst (integer_type_node
, switch_id
);
1519 case_lab
= build_case_label (tmp
, NULL
,
1520 create_artificial_label (tf_loc
));
1521 /* We store the cont_stmt in the pointer map, so that we can recover
1522 it in the loop below. */
1524 cont_map
= new hash_map
<tree
, gimple
*>;
1525 cont_map
->put (case_lab
, q
->cont_stmt
);
1526 case_label_vec
.quick_push (case_lab
);
1529 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1533 last_case
= case_label_vec
[j
];
1535 gcc_assert (last_case
);
1536 gcc_assert (cont_map
);
1538 cont_stmt
= *cont_map
->get (last_case
);
1540 x
= gimple_build_label (CASE_LABEL (last_case
));
1541 gimple_seq_add_stmt (&switch_body
, x
);
1542 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1543 maybe_record_in_goto_queue (state
, cont_stmt
);
1548 replace_goto_queue (tf
);
1550 /* Make sure that the last case is the default label, as one is required.
1551 Then sort the labels, which is also required in GIMPLE. */
1552 CASE_LOW (last_case
) = NULL
;
1553 tree tem
= case_label_vec
.pop ();
1554 gcc_assert (tem
== last_case
);
1555 sort_case_labels (case_label_vec
);
1557 /* Build the switch statement, setting last_case to be the default
1559 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1561 gimple_set_location (switch_stmt
, finally_loc
);
1563 /* Need to link SWITCH_STMT after running replace_goto_queue
1564 due to not wanting to process the same goto stmts twice. */
1565 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1566 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1569 /* Decide whether or not we are going to duplicate the finally block.
1570 There are several considerations.
1572 Second, we'd like to prevent egregious code growth. One way to
1573 do this is to estimate the size of the finally block, multiply
1574 that by the number of copies we'd need to make, and compare against
1575 the estimate of the size of the switch machinery we'd have to add. */
1578 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1580 int f_estimate
, sw_estimate
;
1583 /* If there's an EH_ELSE involved, the exception path is separate
1584 and really doesn't come into play for this computation. */
1585 eh_else
= get_eh_else (finally
);
1588 ndests
-= may_throw
;
1589 finally
= gimple_eh_else_n_body (eh_else
);
1594 gimple_stmt_iterator gsi
;
1599 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1601 /* Duplicate __builtin_stack_restore in the hope of eliminating it
1602 on the EH paths and, consequently, useless cleanups. */
1603 gimple
*stmt
= gsi_stmt (gsi
);
1604 if (!is_gimple_debug (stmt
)
1605 && !gimple_clobber_p (stmt
)
1606 && !gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
1612 /* Finally estimate N times, plus N gotos. */
1613 f_estimate
= estimate_num_insns_seq (finally
, &eni_size_weights
);
1614 f_estimate
= (f_estimate
+ 1) * ndests
;
1616 /* Switch statement (cost 10), N variable assignments, N gotos. */
1617 sw_estimate
= 10 + 2 * ndests
;
1619 /* Optimize for size clearly wants our best guess. */
1620 if (optimize_function_for_size_p (cfun
))
1621 return f_estimate
< sw_estimate
;
1623 /* ??? These numbers are completely made up so far. */
1625 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1627 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1630 /* REG is current region of a LEH state.
1631 is the enclosing region for a possible cleanup region, or the region
1632 itself. Returns TRUE if such a region would be unreachable.
1634 Cleanup regions within a must-not-throw region aren't actually reachable
1635 even if there are throwing stmts within them, because the personality
1636 routine will call terminate before unwinding. */
1639 cleanup_is_dead_in (leh_state
*state
)
1643 eh_region reg
= state
->cur_region
;
1644 while (reg
&& reg
->type
== ERT_CLEANUP
)
1647 gcc_assert (reg
== state
->outer_non_cleanup
);
1650 eh_region reg
= state
->outer_non_cleanup
;
1651 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1654 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1655 to a sequence of labels and blocks, plus the exception region trees
1656 that record all the magic. This is complicated by the need to
1657 arrange for the FINALLY block to be executed on all exits. */
1660 lower_try_finally (struct leh_state
*state
, gtry
*tp
)
1662 struct leh_tf_state this_tf
;
1663 struct leh_state this_state
;
1665 gimple_seq old_eh_seq
;
1667 /* Process the try block. */
1669 memset (&this_tf
, 0, sizeof (this_tf
));
1670 this_tf
.try_finally_expr
= tp
;
1672 this_tf
.outer
= state
;
1673 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
))
1675 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1676 this_state
.cur_region
= this_tf
.region
;
1680 this_tf
.region
= NULL
;
1681 this_state
.cur_region
= state
->cur_region
;
1684 this_state
.outer_non_cleanup
= state
->outer_non_cleanup
;
1685 this_state
.ehp_region
= state
->ehp_region
;
1686 this_state
.tf
= &this_tf
;
1688 old_eh_seq
= eh_seq
;
1691 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1693 /* Determine if the try block is escaped through the bottom. */
1694 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1696 /* Determine if any exceptions are possible within the try block. */
1698 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1699 if (this_tf
.may_throw
)
1700 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1702 /* Determine how many edges (still) reach the finally block. Or rather,
1703 how many destinations are reached by the finally block. Use this to
1704 determine how we process the finally block itself. */
1706 ndests
= this_tf
.dest_array
.length ();
1707 ndests
+= this_tf
.may_fallthru
;
1708 ndests
+= this_tf
.may_return
;
1709 ndests
+= this_tf
.may_throw
;
1711 /* If the FINALLY block is not reachable, dike it out. */
1714 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1715 gimple_try_set_cleanup (tp
, NULL
);
1717 /* If the finally block doesn't fall through, then any destination
1718 we might try to impose there isn't reached either. There may be
1719 some minor amount of cleanup and redirection still needed. */
1720 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1721 lower_try_finally_nofallthru (state
, &this_tf
);
1723 /* We can easily special-case redirection to a single destination. */
1724 else if (ndests
== 1)
1725 lower_try_finally_onedest (state
, &this_tf
);
1726 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1727 gimple_try_cleanup (tp
)))
1728 lower_try_finally_copy (state
, &this_tf
);
1730 lower_try_finally_switch (state
, &this_tf
);
1732 /* If someone requested we add a label at the end of the transformed
1734 if (this_tf
.fallthru_label
)
1736 /* This must be reached only if ndests == 0. */
1737 gimple
*x
= gimple_build_label (this_tf
.fallthru_label
);
1738 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1741 this_tf
.dest_array
.release ();
1742 free (this_tf
.goto_queue
);
1743 if (this_tf
.goto_queue_map
)
1744 delete this_tf
.goto_queue_map
;
1746 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1747 If there was no old eh_seq, then the append is trivially already done. */
1751 eh_seq
= old_eh_seq
;
1754 gimple_seq new_eh_seq
= eh_seq
;
1755 eh_seq
= old_eh_seq
;
1756 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1760 return this_tf
.top_p_seq
;
1763 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1764 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1765 exception region trees that records all the magic. */
1768 lower_catch (struct leh_state
*state
, gtry
*tp
)
1770 eh_region try_region
= NULL
;
1771 struct leh_state this_state
= *state
;
1772 gimple_stmt_iterator gsi
;
1774 gimple_seq new_seq
, cleanup
;
1776 geh_dispatch
*eh_dispatch
;
1777 location_t try_catch_loc
= gimple_location (tp
);
1778 location_t catch_loc
= UNKNOWN_LOCATION
;
1780 if (flag_exceptions
)
1782 try_region
= gen_eh_region_try (state
->cur_region
);
1783 this_state
.cur_region
= try_region
;
1784 this_state
.outer_non_cleanup
= this_state
.cur_region
;
1787 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1789 if (!eh_region_may_contain_throw (try_region
))
1790 return gimple_try_eval (tp
);
1793 eh_dispatch
= gimple_build_eh_dispatch (try_region
->index
);
1794 gimple_seq_add_stmt (&new_seq
, eh_dispatch
);
1795 emit_resx (&new_seq
, try_region
);
1797 this_state
.cur_region
= state
->cur_region
;
1798 this_state
.outer_non_cleanup
= state
->outer_non_cleanup
;
1799 this_state
.ehp_region
= try_region
;
1801 /* Add eh_seq from lowering EH in the cleanup sequence after the cleanup
1802 itself, so that e.g. for coverage purposes the nested cleanups don't
1803 appear before the cleanup body. See PR64634 for details. */
1804 gimple_seq old_eh_seq
= eh_seq
;
1808 cleanup
= gimple_try_cleanup (tp
);
1809 for (gsi
= gsi_start (cleanup
);
1817 catch_stmt
= as_a
<gcatch
*> (gsi_stmt (gsi
));
1818 if (catch_loc
== UNKNOWN_LOCATION
)
1819 catch_loc
= gimple_location (catch_stmt
);
1820 c
= gen_eh_region_catch (try_region
, gimple_catch_types (catch_stmt
));
1822 handler
= gimple_catch_handler (catch_stmt
);
1823 lower_eh_constructs_1 (&this_state
, &handler
);
1825 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1826 x
= gimple_build_label (c
->label
);
1827 gimple_seq_add_stmt (&new_seq
, x
);
1829 gimple_seq_add_seq (&new_seq
, handler
);
1831 if (gimple_seq_may_fallthru (new_seq
))
1834 out_label
= create_artificial_label (try_catch_loc
);
1836 x
= gimple_build_goto (out_label
);
1837 gimple_seq_add_stmt (&new_seq
, x
);
1843 /* Try to set a location on the dispatching construct to avoid inheriting
1844 the location of the previous statement. */
1845 gimple_set_location (eh_dispatch
, catch_loc
);
1847 gimple_try_set_cleanup (tp
, new_seq
);
1849 gimple_seq new_eh_seq
= eh_seq
;
1850 eh_seq
= old_eh_seq
;
1851 gimple_seq ret_seq
= frob_into_branch_around (tp
, try_region
, out_label
);
1852 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1856 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1857 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1858 region trees that record all the magic. */
1861 lower_eh_filter (struct leh_state
*state
, gtry
*tp
)
1863 struct leh_state this_state
= *state
;
1864 eh_region this_region
= NULL
;
1868 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1870 if (flag_exceptions
)
1872 this_region
= gen_eh_region_allowed (state
->cur_region
,
1873 gimple_eh_filter_types (inner
));
1874 this_state
.cur_region
= this_region
;
1875 this_state
.outer_non_cleanup
= this_state
.cur_region
;
1878 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1880 if (!eh_region_may_contain_throw (this_region
))
1881 return gimple_try_eval (tp
);
1883 this_state
.cur_region
= state
->cur_region
;
1884 this_state
.ehp_region
= this_region
;
1887 x
= gimple_build_eh_dispatch (this_region
->index
);
1888 gimple_set_location (x
, gimple_location (tp
));
1889 gimple_seq_add_stmt (&new_seq
, x
);
1890 emit_resx (&new_seq
, this_region
);
1892 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1893 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1894 gimple_seq_add_stmt (&new_seq
, x
);
1896 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1897 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1899 gimple_try_set_cleanup (tp
, new_seq
);
1901 return frob_into_branch_around (tp
, this_region
, NULL
);
1904 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1905 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1906 plus the exception region trees that record all the magic. */
1909 lower_eh_must_not_throw (struct leh_state
*state
, gtry
*tp
)
1911 struct leh_state this_state
= *state
;
1913 if (flag_exceptions
)
1915 gimple
*inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1916 eh_region this_region
;
1918 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1919 this_region
->u
.must_not_throw
.failure_decl
1920 = gimple_eh_must_not_throw_fndecl (
1921 as_a
<geh_mnt
*> (inner
));
1922 this_region
->u
.must_not_throw
.failure_loc
1923 = LOCATION_LOCUS (gimple_location (tp
));
1925 /* In order to get mangling applied to this decl, we must mark it
1926 used now. Otherwise, pass_ipa_free_lang_data won't think it
1928 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1930 this_state
.cur_region
= this_region
;
1931 this_state
.outer_non_cleanup
= this_state
.cur_region
;
1934 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1936 return gimple_try_eval (tp
);
1939 /* Implement a cleanup expression. This is similar to try-finally,
1940 except that we only execute the cleanup block for exception edges. */
1943 lower_cleanup (struct leh_state
*state
, gtry
*tp
)
1945 struct leh_state this_state
= *state
;
1946 eh_region this_region
= NULL
;
1947 struct leh_tf_state fake_tf
;
1949 bool cleanup_dead
= cleanup_is_dead_in (state
);
1951 if (flag_exceptions
&& !cleanup_dead
)
1953 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1954 this_state
.cur_region
= this_region
;
1955 this_state
.outer_non_cleanup
= state
->outer_non_cleanup
;
1958 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1960 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1961 return gimple_try_eval (tp
);
1963 /* Build enough of a try-finally state so that we can reuse
1964 honor_protect_cleanup_actions. */
1965 memset (&fake_tf
, 0, sizeof (fake_tf
));
1966 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1967 fake_tf
.outer
= state
;
1968 fake_tf
.region
= this_region
;
1969 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1970 fake_tf
.may_throw
= true;
1972 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1974 if (fake_tf
.may_throw
)
1976 /* In this case honor_protect_cleanup_actions had nothing to do,
1977 and we should process this normally. */
1978 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1979 result
= frob_into_branch_around (tp
, this_region
,
1980 fake_tf
.fallthru_label
);
1984 /* In this case honor_protect_cleanup_actions did nearly all of
1985 the work. All we have left is to append the fallthru_label. */
1987 result
= gimple_try_eval (tp
);
1988 if (fake_tf
.fallthru_label
)
1990 gimple
*x
= gimple_build_label (fake_tf
.fallthru_label
);
1991 gimple_seq_add_stmt (&result
, x
);
1997 /* Main loop for lowering eh constructs. Also moves gsi to the next
2001 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
2005 gimple
*stmt
= gsi_stmt (*gsi
);
2007 switch (gimple_code (stmt
))
2011 tree fndecl
= gimple_call_fndecl (stmt
);
2014 if (fndecl
&& fndecl_built_in_p (fndecl
, BUILT_IN_NORMAL
))
2015 switch (DECL_FUNCTION_CODE (fndecl
))
2017 case BUILT_IN_EH_POINTER
:
2018 /* The front end may have generated a call to
2019 __builtin_eh_pointer (0) within a catch region. Replace
2020 this zero argument with the current catch region number. */
2021 if (state
->ehp_region
)
2023 tree nr
= build_int_cst (integer_type_node
,
2024 state
->ehp_region
->index
);
2025 gimple_call_set_arg (stmt
, 0, nr
);
2029 /* The user has dome something silly. Remove it. */
2030 rhs
= null_pointer_node
;
2035 case BUILT_IN_EH_FILTER
:
2036 /* ??? This should never appear, but since it's a builtin it
2037 is accessible to abuse by users. Just remove it and
2038 replace the use with the arbitrary value zero. */
2039 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2041 lhs
= gimple_call_lhs (stmt
);
2042 x
= gimple_build_assign (lhs
, rhs
);
2043 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2046 case BUILT_IN_EH_COPY_VALUES
:
2047 /* Likewise this should not appear. Remove it. */
2048 gsi_remove (gsi
, true);
2058 /* If the stmt can throw, use a new temporary for the assignment
2059 to a LHS. This makes sure the old value of the LHS is
2060 available on the EH edge. Only do so for statements that
2061 potentially fall through (no noreturn calls e.g.), otherwise
2062 this new assignment might create fake fallthru regions. */
2063 if (stmt_could_throw_p (cfun
, stmt
)
2064 && gimple_has_lhs (stmt
)
2065 && gimple_stmt_may_fallthru (stmt
)
2066 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2067 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2069 tree lhs
= gimple_get_lhs (stmt
);
2070 tree tmp
= create_tmp_var (TREE_TYPE (lhs
));
2071 gimple
*s
= gimple_build_assign (lhs
, tmp
);
2072 gimple_set_location (s
, gimple_location (stmt
));
2073 gimple_set_block (s
, gimple_block (stmt
));
2074 gimple_set_lhs (stmt
, tmp
);
2075 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2077 /* Look for things that can throw exceptions, and record them. */
2078 if (state
->cur_region
&& stmt_could_throw_p (cfun
, stmt
))
2080 record_stmt_eh_region (state
->cur_region
, stmt
);
2081 note_eh_region_may_contain_throw (state
->cur_region
);
2088 maybe_record_in_goto_queue (state
, stmt
);
2092 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2097 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2098 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2099 replace
= lower_try_finally (state
, try_stmt
);
2102 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2105 replace
= gimple_try_eval (try_stmt
);
2106 lower_eh_constructs_1 (state
, &replace
);
2109 switch (gimple_code (x
))
2112 replace
= lower_catch (state
, try_stmt
);
2114 case GIMPLE_EH_FILTER
:
2115 replace
= lower_eh_filter (state
, try_stmt
);
2117 case GIMPLE_EH_MUST_NOT_THROW
:
2118 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2120 case GIMPLE_EH_ELSE
:
2121 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2124 replace
= lower_cleanup (state
, try_stmt
);
2130 /* Remove the old stmt and insert the transformed sequence
2132 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2133 gsi_remove (gsi
, true);
2135 /* Return since we don't want gsi_next () */
2138 case GIMPLE_EH_ELSE
:
2139 /* We should be eliminating this in lower_try_finally et al. */
2143 /* A type, a decl, or some kind of statement that we're not
2144 interested in. Don't walk them. */
2151 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2154 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2156 gimple_stmt_iterator gsi
;
2157 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2158 lower_eh_constructs_2 (state
, &gsi
);
2163 const pass_data pass_data_lower_eh
=
2165 GIMPLE_PASS
, /* type */
2167 OPTGROUP_NONE
, /* optinfo_flags */
2168 TV_TREE_EH
, /* tv_id */
2169 PROP_gimple_lcf
, /* properties_required */
2170 PROP_gimple_leh
, /* properties_provided */
2171 0, /* properties_destroyed */
2172 0, /* todo_flags_start */
2173 0, /* todo_flags_finish */
2176 class pass_lower_eh
: public gimple_opt_pass
2179 pass_lower_eh (gcc::context
*ctxt
)
2180 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2183 /* opt_pass methods: */
2184 virtual unsigned int execute (function
*);
2186 }; // class pass_lower_eh
2189 pass_lower_eh::execute (function
*fun
)
2191 struct leh_state null_state
;
2194 bodyp
= gimple_body (current_function_decl
);
2198 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2199 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2200 memset (&null_state
, 0, sizeof (null_state
));
2202 collect_finally_tree_1 (bodyp
, NULL
);
2203 lower_eh_constructs_1 (&null_state
, &bodyp
);
2204 gimple_set_body (current_function_decl
, bodyp
);
2206 /* We assume there's a return statement, or something, at the end of
2207 the function, and thus ploping the EH sequence afterward won't
2209 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2210 gimple_seq_add_seq (&bodyp
, eh_seq
);
2212 /* We assume that since BODYP already existed, adding EH_SEQ to it
2213 didn't change its value, and we don't have to re-set the function. */
2214 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2216 delete finally_tree
;
2217 finally_tree
= NULL
;
2218 BITMAP_FREE (eh_region_may_contain_throw_map
);
2221 /* If this function needs a language specific EH personality routine
2222 and the frontend didn't already set one do so now. */
2223 if (function_needs_eh_personality (fun
) == eh_personality_lang
2224 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2225 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2226 = lang_hooks
.eh_personality ();
2234 make_pass_lower_eh (gcc::context
*ctxt
)
2236 return new pass_lower_eh (ctxt
);
2239 /* Create the multiple edges from an EH_DISPATCH statement to all of
2240 the possible handlers for its EH region. Return true if there's
2241 no fallthru edge; false if there is. */
2244 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2248 basic_block src
, dst
;
2250 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2251 src
= gimple_bb (stmt
);
2256 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2258 dst
= label_to_block (cfun
, c
->label
);
2259 make_edge (src
, dst
, 0);
2261 /* A catch-all handler doesn't have a fallthru. */
2262 if (c
->type_list
== NULL
)
2267 case ERT_ALLOWED_EXCEPTIONS
:
2268 dst
= label_to_block (cfun
, r
->u
.allowed
.label
);
2269 make_edge (src
, dst
, 0);
2279 /* Create the single EH edge from STMT to its nearest landing pad,
2280 if there is such a landing pad within the current function. */
2283 make_eh_edges (gimple
*stmt
)
2285 basic_block src
, dst
;
2289 lp_nr
= lookup_stmt_eh_lp (stmt
);
2293 lp
= get_eh_landing_pad_from_number (lp_nr
);
2294 gcc_assert (lp
!= NULL
);
2296 src
= gimple_bb (stmt
);
2297 dst
= label_to_block (cfun
, lp
->post_landing_pad
);
2298 make_edge (src
, dst
, EDGE_EH
);
2301 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2302 do not actually perform the final edge redirection.
2304 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2305 we intend to change the destination EH region as well; this means
2306 EH_LANDING_PAD_NR must already be set on the destination block label.
2307 If false, we're being called from generic cfg manipulation code and we
2308 should preserve our place within the region tree. */
2311 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2313 eh_landing_pad old_lp
, new_lp
;
2316 int old_lp_nr
, new_lp_nr
;
2317 tree old_label
, new_label
;
2321 old_bb
= edge_in
->dest
;
2322 old_label
= gimple_block_label (old_bb
);
2323 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2324 gcc_assert (old_lp_nr
> 0);
2325 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2327 throw_stmt
= last_stmt (edge_in
->src
);
2328 gcc_checking_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2330 new_label
= gimple_block_label (new_bb
);
2332 /* Look for an existing region that might be using NEW_BB already. */
2333 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2336 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2337 gcc_assert (new_lp
);
2339 /* Unless CHANGE_REGION is true, the new and old landing pad
2340 had better be associated with the same EH region. */
2341 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2346 gcc_assert (!change_region
);
2349 /* Notice when we redirect the last EH edge away from OLD_BB. */
2350 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2351 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2356 /* NEW_LP already exists. If there are still edges into OLD_LP,
2357 there's nothing to do with the EH tree. If there are no more
2358 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2359 If CHANGE_REGION is true, then our caller is expecting to remove
2361 if (e
== NULL
&& !change_region
)
2362 remove_eh_landing_pad (old_lp
);
2366 /* No correct landing pad exists. If there are no more edges
2367 into OLD_LP, then we can simply re-use the existing landing pad.
2368 Otherwise, we have to create a new landing pad. */
2371 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2375 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2376 new_lp
->post_landing_pad
= new_label
;
2377 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2380 /* Maybe move the throwing statement to the new region. */
2381 if (old_lp
!= new_lp
)
2383 remove_stmt_from_eh_lp (throw_stmt
);
2384 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2388 /* Redirect EH edge E to NEW_BB. */
2391 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2393 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2394 return ssa_redirect_edge (edge_in
, new_bb
);
2397 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2398 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2399 The actual edge update will happen in the caller. */
2402 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2404 tree new_lab
= gimple_block_label (new_bb
);
2405 bool any_changed
= false;
2410 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2414 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2416 old_bb
= label_to_block (cfun
, c
->label
);
2417 if (old_bb
== e
->dest
)
2425 case ERT_ALLOWED_EXCEPTIONS
:
2426 old_bb
= label_to_block (cfun
, r
->u
.allowed
.label
);
2427 gcc_assert (old_bb
== e
->dest
);
2428 r
->u
.allowed
.label
= new_lab
;
2436 gcc_assert (any_changed
);
2439 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2442 operation_could_trap_helper_p (enum tree_code op
,
2453 case TRUNC_DIV_EXPR
:
2455 case FLOOR_DIV_EXPR
:
2456 case ROUND_DIV_EXPR
:
2457 case EXACT_DIV_EXPR
:
2459 case FLOOR_MOD_EXPR
:
2460 case ROUND_MOD_EXPR
:
2461 case TRUNC_MOD_EXPR
:
2466 return flag_trapping_math
;
2467 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2476 /* Some floating point comparisons may trap. */
2481 case UNORDERED_EXPR
:
2493 /* These operations don't trap with floating point. */
2499 /* ABSU_EXPR never traps. */
2505 /* Any floating arithmetic may trap. */
2506 if (fp_operation
&& flag_trapping_math
)
2514 /* Constructing an object cannot trap. */
2519 /* Whether *COND_EXPR can trap depends on whether the
2520 first argument can trap, so signal it as not handled.
2521 Whether lhs is floating or not doesn't matter. */
2526 /* Any floating arithmetic may trap. */
2527 if (fp_operation
&& flag_trapping_math
)
2535 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2536 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2537 type operands that may trap. If OP is a division operator, DIVISOR contains
2538 the value of the divisor. */
2541 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2544 bool honor_nans
= (fp_operation
&& flag_trapping_math
2545 && !flag_finite_math_only
);
2546 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2549 /* This function cannot tell whether or not COND_EXPR and VEC_COND_EXPR could
2550 trap, because that depends on the respective condition op. */
2551 gcc_assert (op
!= COND_EXPR
&& op
!= VEC_COND_EXPR
);
2553 if (TREE_CODE_CLASS (op
) != tcc_comparison
2554 && TREE_CODE_CLASS (op
) != tcc_unary
2555 && TREE_CODE_CLASS (op
) != tcc_binary
)
2558 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2559 honor_nans
, honor_snans
, divisor
,
2564 /* Returns true if it is possible to prove that the index of
2565 an array access REF (an ARRAY_REF expression) falls into the
2569 in_array_bounds_p (tree ref
)
2571 tree idx
= TREE_OPERAND (ref
, 1);
2574 if (TREE_CODE (idx
) != INTEGER_CST
)
2577 min
= array_ref_low_bound (ref
);
2578 max
= array_ref_up_bound (ref
);
2581 || TREE_CODE (min
) != INTEGER_CST
2582 || TREE_CODE (max
) != INTEGER_CST
)
2585 if (tree_int_cst_lt (idx
, min
)
2586 || tree_int_cst_lt (max
, idx
))
2592 /* Returns true if it is possible to prove that the range of
2593 an array access REF (an ARRAY_RANGE_REF expression) falls
2594 into the array bounds. */
2597 range_in_array_bounds_p (tree ref
)
2599 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2600 tree range_min
, range_max
, min
, max
;
2602 range_min
= TYPE_MIN_VALUE (domain_type
);
2603 range_max
= TYPE_MAX_VALUE (domain_type
);
2606 || TREE_CODE (range_min
) != INTEGER_CST
2607 || TREE_CODE (range_max
) != INTEGER_CST
)
2610 min
= array_ref_low_bound (ref
);
2611 max
= array_ref_up_bound (ref
);
2614 || TREE_CODE (min
) != INTEGER_CST
2615 || TREE_CODE (max
) != INTEGER_CST
)
2618 if (tree_int_cst_lt (range_min
, min
)
2619 || tree_int_cst_lt (max
, range_max
))
2625 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2626 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2627 This routine expects only GIMPLE lhs or rhs input. */
2630 tree_could_trap_p (tree expr
)
2632 enum tree_code code
;
2633 bool fp_operation
= false;
2634 bool honor_trapv
= false;
2635 tree t
, base
, div
= NULL_TREE
;
2640 /* In COND_EXPR and VEC_COND_EXPR only the condition may trap, but
2641 they won't appear as operands in GIMPLE form, so this is just for the
2642 GENERIC uses where it needs to recurse on the operands and so
2643 *COND_EXPR itself doesn't trap. */
2644 if (TREE_CODE (expr
) == COND_EXPR
|| TREE_CODE (expr
) == VEC_COND_EXPR
)
2647 code
= TREE_CODE (expr
);
2648 t
= TREE_TYPE (expr
);
2652 if (COMPARISON_CLASS_P (expr
))
2653 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2655 fp_operation
= FLOAT_TYPE_P (t
);
2656 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2659 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2660 div
= TREE_OPERAND (expr
, 1);
2661 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2671 case VIEW_CONVERT_EXPR
:
2672 case WITH_SIZE_EXPR
:
2673 expr
= TREE_OPERAND (expr
, 0);
2674 code
= TREE_CODE (expr
);
2677 case ARRAY_RANGE_REF
:
2678 base
= TREE_OPERAND (expr
, 0);
2679 if (tree_could_trap_p (base
))
2681 if (TREE_THIS_NOTRAP (expr
))
2683 return !range_in_array_bounds_p (expr
);
2686 base
= TREE_OPERAND (expr
, 0);
2687 if (tree_could_trap_p (base
))
2689 if (TREE_THIS_NOTRAP (expr
))
2691 return !in_array_bounds_p (expr
);
2693 case TARGET_MEM_REF
:
2695 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2696 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2698 if (TREE_THIS_NOTRAP (expr
))
2700 /* We cannot prove that the access is in-bounds when we have
2701 variable-index TARGET_MEM_REFs. */
2702 if (code
== TARGET_MEM_REF
2703 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2705 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2707 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2708 poly_offset_int off
= mem_ref_offset (expr
);
2709 if (maybe_lt (off
, 0))
2711 if (TREE_CODE (base
) == STRING_CST
)
2712 return maybe_le (TREE_STRING_LENGTH (base
), off
);
2713 tree size
= DECL_SIZE_UNIT (base
);
2714 if (size
== NULL_TREE
2715 || !poly_int_tree_p (size
)
2716 || maybe_le (wi::to_poly_offset (size
), off
))
2718 /* Now we are sure the first byte of the access is inside
2725 return !TREE_THIS_NOTRAP (expr
);
2728 return TREE_THIS_VOLATILE (expr
);
2731 t
= get_callee_fndecl (expr
);
2732 /* Assume that calls to weak functions may trap. */
2733 if (!t
|| !DECL_P (t
))
2736 return tree_could_trap_p (t
);
2740 /* Assume that accesses to weak functions may trap, unless we know
2741 they are certainly defined in current TU or in some other
2743 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2745 cgraph_node
*node
= cgraph_node::get (expr
);
2747 node
= node
->function_symbol ();
2748 return !(node
&& node
->in_other_partition
);
2753 /* Assume that accesses to weak vars may trap, unless we know
2754 they are certainly defined in current TU or in some other
2756 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2758 varpool_node
*node
= varpool_node::get (expr
);
2760 node
= node
->ultimate_alias_target ();
2761 return !(node
&& node
->in_other_partition
);
2770 /* Return non-NULL if there is an integer operation with trapping overflow
2771 we can rewrite into non-trapping. Called via walk_tree from
2772 rewrite_to_non_trapping_overflow. */
2775 find_trapping_overflow (tree
*tp
, int *walk_subtrees
, void *data
)
2778 && ANY_INTEGRAL_TYPE_P (TREE_TYPE (*tp
))
2779 && !operation_no_trapping_overflow (TREE_TYPE (*tp
), TREE_CODE (*tp
)))
2781 if (IS_TYPE_OR_DECL_P (*tp
)
2782 || (TREE_CODE (*tp
) == SAVE_EXPR
&& data
== NULL
))
2787 /* Rewrite selected operations into unsigned arithmetics, so that they
2788 don't trap on overflow. */
2791 replace_trapping_overflow (tree
*tp
, int *walk_subtrees
, void *data
)
2793 if (find_trapping_overflow (tp
, walk_subtrees
, data
))
2795 tree type
= TREE_TYPE (*tp
);
2796 tree utype
= unsigned_type_for (type
);
2798 int len
= TREE_OPERAND_LENGTH (*tp
);
2799 for (int i
= 0; i
< len
; ++i
)
2800 walk_tree (&TREE_OPERAND (*tp
, i
), replace_trapping_overflow
,
2801 data
, (hash_set
<tree
> *) data
);
2803 if (TREE_CODE (*tp
) == ABS_EXPR
)
2805 TREE_SET_CODE (*tp
, ABSU_EXPR
);
2806 TREE_TYPE (*tp
) = utype
;
2807 *tp
= fold_convert (type
, *tp
);
2811 TREE_TYPE (*tp
) = utype
;
2812 len
= TREE_OPERAND_LENGTH (*tp
);
2813 for (int i
= 0; i
< len
; ++i
)
2814 TREE_OPERAND (*tp
, i
)
2815 = fold_convert (utype
, TREE_OPERAND (*tp
, i
));
2816 *tp
= fold_convert (type
, *tp
);
2822 /* If any subexpression of EXPR can trap due to -ftrapv, rewrite it
2823 using unsigned arithmetics to avoid traps in it. */
2826 rewrite_to_non_trapping_overflow (tree expr
)
2830 hash_set
<tree
> pset
;
2831 if (!walk_tree (&expr
, find_trapping_overflow
, &pset
, &pset
))
2833 expr
= unshare_expr (expr
);
2835 walk_tree (&expr
, replace_trapping_overflow
, &pset
, &pset
);
2839 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2840 an assignment or a conditional) may throw. */
2843 stmt_could_throw_1_p (gassign
*stmt
)
2845 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2846 bool honor_nans
= false;
2847 bool honor_snans
= false;
2848 bool fp_operation
= false;
2849 bool honor_trapv
= false;
2854 if (TREE_CODE_CLASS (code
) == tcc_comparison
2855 || TREE_CODE_CLASS (code
) == tcc_unary
2856 || TREE_CODE_CLASS (code
) == tcc_binary
)
2858 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2859 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2861 t
= gimple_expr_type (stmt
);
2862 fp_operation
= FLOAT_TYPE_P (t
);
2865 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2866 honor_snans
= flag_signaling_nans
!= 0;
2868 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2872 /* First check the LHS. */
2873 if (tree_could_trap_p (gimple_assign_lhs (stmt
)))
2876 /* Check if the main expression may trap. */
2877 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2878 honor_nans
, honor_snans
,
2879 gimple_assign_rhs2 (stmt
),
2884 /* If the expression does not trap, see if any of the individual operands may
2886 for (i
= 1; i
< gimple_num_ops (stmt
); i
++)
2887 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2894 /* Return true if statement STMT within FUN could throw an exception. */
2897 stmt_could_throw_p (function
*fun
, gimple
*stmt
)
2899 if (!flag_exceptions
)
2902 /* The only statements that can throw an exception are assignments,
2903 conditionals, calls, resx, and asms. */
2904 switch (gimple_code (stmt
))
2910 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2914 if (fun
&& !fun
->can_throw_non_call_exceptions
)
2916 gcond
*cond
= as_a
<gcond
*> (stmt
);
2917 tree lhs
= gimple_cond_lhs (cond
);
2918 return operation_could_trap_p (gimple_cond_code (cond
),
2919 FLOAT_TYPE_P (TREE_TYPE (lhs
)),
2924 if ((fun
&& !fun
->can_throw_non_call_exceptions
)
2925 || gimple_clobber_p (stmt
))
2927 return stmt_could_throw_1_p (as_a
<gassign
*> (stmt
));
2930 if (fun
&& !fun
->can_throw_non_call_exceptions
)
2932 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2939 /* Return true if STMT in function FUN must be assumed necessary because of
2940 non-call exceptions. */
2943 stmt_unremovable_because_of_non_call_eh_p (function
*fun
, gimple
*stmt
)
2945 return (fun
->can_throw_non_call_exceptions
2946 && !fun
->can_delete_dead_exceptions
2947 && stmt_could_throw_p (fun
, stmt
));
2950 /* Return true if expression T could throw an exception. */
2953 tree_could_throw_p (tree t
)
2955 if (!flag_exceptions
)
2957 if (TREE_CODE (t
) == MODIFY_EXPR
)
2959 if (cfun
->can_throw_non_call_exceptions
2960 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2962 t
= TREE_OPERAND (t
, 1);
2965 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2966 t
= TREE_OPERAND (t
, 0);
2967 if (TREE_CODE (t
) == CALL_EXPR
)
2968 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2969 if (cfun
->can_throw_non_call_exceptions
)
2970 return tree_could_trap_p (t
);
2974 /* Return true if STMT can throw an exception that is not caught within its
2975 function FUN. FUN can be NULL but the function is extra conservative
2979 stmt_can_throw_external (function
*fun
, gimple
*stmt
)
2983 if (!stmt_could_throw_p (fun
, stmt
))
2988 lp_nr
= lookup_stmt_eh_lp_fn (fun
, stmt
);
2992 /* Return true if STMT can throw an exception that is caught within its
2996 stmt_can_throw_internal (function
*fun
, gimple
*stmt
)
3000 gcc_checking_assert (fun
);
3001 if (!stmt_could_throw_p (fun
, stmt
))
3004 lp_nr
= lookup_stmt_eh_lp_fn (fun
, stmt
);
3008 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
3009 remove any entry it might have from the EH table. Return true if
3010 any change was made. */
3013 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple
*stmt
)
3015 if (stmt_could_throw_p (ifun
, stmt
))
3017 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
3020 /* Likewise, but always use the current function. */
3023 maybe_clean_eh_stmt (gimple
*stmt
)
3025 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
3028 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
3029 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
3030 in the table if it should be in there. Return TRUE if a replacement was
3031 done that my require an EH edge purge. */
3034 maybe_clean_or_replace_eh_stmt (gimple
*old_stmt
, gimple
*new_stmt
)
3036 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
3040 bool new_stmt_could_throw
= stmt_could_throw_p (cfun
, new_stmt
);
3042 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
3045 remove_stmt_from_eh_lp (old_stmt
);
3046 if (new_stmt_could_throw
)
3048 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
3058 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
3059 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
3060 operand is the return value of duplicate_eh_regions. */
3063 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple
*new_stmt
,
3064 struct function
*old_fun
, gimple
*old_stmt
,
3065 hash_map
<void *, void *> *map
,
3068 int old_lp_nr
, new_lp_nr
;
3070 if (!stmt_could_throw_p (new_fun
, new_stmt
))
3073 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
3076 if (default_lp_nr
== 0)
3078 new_lp_nr
= default_lp_nr
;
3080 else if (old_lp_nr
> 0)
3082 eh_landing_pad old_lp
, new_lp
;
3084 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
3085 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
3086 new_lp_nr
= new_lp
->index
;
3090 eh_region old_r
, new_r
;
3092 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
3093 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
3094 new_lp_nr
= -new_r
->index
;
3097 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
3101 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
3102 and thus no remapping is required. */
3105 maybe_duplicate_eh_stmt (gimple
*new_stmt
, gimple
*old_stmt
)
3109 if (!stmt_could_throw_p (cfun
, new_stmt
))
3112 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
3116 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
3120 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
3121 GIMPLE_TRY) that are similar enough to be considered the same. Currently
3122 this only handles handlers consisting of a single call, as that's the
3123 important case for C++: a destructor call for a particular object showing
3124 up in multiple handlers. */
3127 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
3129 gimple_stmt_iterator gsi
;
3130 gimple
*ones
, *twos
;
3133 gsi
= gsi_start (oneh
);
3134 if (!gsi_one_before_end_p (gsi
))
3136 ones
= gsi_stmt (gsi
);
3138 gsi
= gsi_start (twoh
);
3139 if (!gsi_one_before_end_p (gsi
))
3141 twos
= gsi_stmt (gsi
);
3143 if (!is_gimple_call (ones
)
3144 || !is_gimple_call (twos
)
3145 || gimple_call_lhs (ones
)
3146 || gimple_call_lhs (twos
)
3147 || gimple_call_chain (ones
)
3148 || gimple_call_chain (twos
)
3149 || !gimple_call_same_target_p (ones
, twos
)
3150 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3153 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3154 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3155 gimple_call_arg (twos
, ai
), 0))
3162 try { A() } finally { try { ~B() } catch { ~A() } }
3163 try { ... } finally { ~A() }
3165 try { A() } catch { ~B() }
3166 try { ~B() ... } finally { ~A() }
3168 This occurs frequently in C++, where A is a local variable and B is a
3169 temporary used in the initializer for A. */
3172 optimize_double_finally (gtry
*one
, gtry
*two
)
3175 gimple_stmt_iterator gsi
;
3178 cleanup
= gimple_try_cleanup (one
);
3179 gsi
= gsi_start (cleanup
);
3180 if (!gsi_one_before_end_p (gsi
))
3183 oneh
= gsi_stmt (gsi
);
3184 if (gimple_code (oneh
) != GIMPLE_TRY
3185 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3188 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3190 gimple_seq seq
= gimple_try_eval (oneh
);
3192 gimple_try_set_cleanup (one
, seq
);
3193 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3194 seq
= copy_gimple_seq_and_replace_locals (seq
);
3195 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3196 gimple_try_set_eval (two
, seq
);
3200 /* Perform EH refactoring optimizations that are simpler to do when code
3201 flow has been lowered but EH structures haven't. */
3204 refactor_eh_r (gimple_seq seq
)
3206 gimple_stmt_iterator gsi
;
3211 gsi
= gsi_start (seq
);
3215 if (gsi_end_p (gsi
))
3218 two
= gsi_stmt (gsi
);
3220 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3221 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3222 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3223 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3224 optimize_double_finally (try_one
, try_two
);
3226 switch (gimple_code (one
))
3229 refactor_eh_r (gimple_try_eval (one
));
3230 refactor_eh_r (gimple_try_cleanup (one
));
3233 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3235 case GIMPLE_EH_FILTER
:
3236 refactor_eh_r (gimple_eh_filter_failure (one
));
3238 case GIMPLE_EH_ELSE
:
3240 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3241 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3242 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3257 const pass_data pass_data_refactor_eh
=
3259 GIMPLE_PASS
, /* type */
3261 OPTGROUP_NONE
, /* optinfo_flags */
3262 TV_TREE_EH
, /* tv_id */
3263 PROP_gimple_lcf
, /* properties_required */
3264 0, /* properties_provided */
3265 0, /* properties_destroyed */
3266 0, /* todo_flags_start */
3267 0, /* todo_flags_finish */
3270 class pass_refactor_eh
: public gimple_opt_pass
3273 pass_refactor_eh (gcc::context
*ctxt
)
3274 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3277 /* opt_pass methods: */
3278 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3279 virtual unsigned int execute (function
*)
3281 refactor_eh_r (gimple_body (current_function_decl
));
3285 }; // class pass_refactor_eh
3290 make_pass_refactor_eh (gcc::context
*ctxt
)
3292 return new pass_refactor_eh (ctxt
);
3295 /* At the end of gimple optimization, we can lower RESX. */
3298 lower_resx (basic_block bb
, gresx
*stmt
,
3299 hash_map
<eh_region
, tree
> *mnt_map
)
3302 eh_region src_r
, dst_r
;
3303 gimple_stmt_iterator gsi
;
3308 lp_nr
= lookup_stmt_eh_lp (stmt
);
3310 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3314 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3315 gsi
= gsi_last_bb (bb
);
3319 /* We can wind up with no source region when pass_cleanup_eh shows
3320 that there are no entries into an eh region and deletes it, but
3321 then the block that contains the resx isn't removed. This can
3322 happen without optimization when the switch statement created by
3323 lower_try_finally_switch isn't simplified to remove the eh case.
3325 Resolve this by expanding the resx node to an abort. */
3327 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3328 x
= gimple_build_call (fn
, 0);
3329 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3331 while (EDGE_COUNT (bb
->succs
) > 0)
3332 remove_edge (EDGE_SUCC (bb
, 0));
3336 /* When we have a destination region, we resolve this by copying
3337 the excptr and filter values into place, and changing the edge
3338 to immediately after the landing pad. */
3346 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3347 the failure decl into a new block, if needed. */
3348 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3350 tree
*slot
= mnt_map
->get (dst_r
);
3353 gimple_stmt_iterator gsi2
;
3355 new_bb
= create_empty_bb (bb
);
3356 new_bb
->count
= bb
->count
;
3357 add_bb_to_loop (new_bb
, bb
->loop_father
);
3358 lab
= gimple_block_label (new_bb
);
3359 gsi2
= gsi_start_bb (new_bb
);
3361 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3362 x
= gimple_build_call (fn
, 0);
3363 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3364 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3366 mnt_map
->put (dst_r
, lab
);
3371 new_bb
= label_to_block (cfun
, lab
);
3374 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3375 e
= make_single_succ_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3380 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3382 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3383 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3384 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3385 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3387 /* Update the flags for the outgoing edge. */
3388 e
= single_succ_edge (bb
);
3389 gcc_assert (e
->flags
& EDGE_EH
);
3390 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3391 e
->probability
= profile_probability::always ();
3393 /* If there are no more EH users of the landing pad, delete it. */
3394 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3395 if (e
->flags
& EDGE_EH
)
3399 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3400 remove_eh_landing_pad (lp
);
3410 /* When we don't have a destination region, this exception escapes
3411 up the call chain. We resolve this by generating a call to the
3412 _Unwind_Resume library function. */
3414 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3415 with no arguments for C++. Check for that. */
3416 if (src_r
->use_cxa_end_cleanup
)
3418 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3419 x
= gimple_build_call (fn
, 0);
3420 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3424 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3425 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3426 x
= gimple_build_call (fn
, 1, src_nr
);
3427 var
= create_tmp_var (ptr_type_node
);
3428 var
= make_ssa_name (var
, x
);
3429 gimple_call_set_lhs (x
, var
);
3430 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3432 /* When exception handling is delegated to a caller function, we
3433 have to guarantee that shadow memory variables living on stack
3434 will be cleaner before control is given to a parent function. */
3435 if (sanitize_flags_p (SANITIZE_ADDRESS
))
3438 = builtin_decl_implicit (BUILT_IN_ASAN_HANDLE_NO_RETURN
);
3439 gimple
*g
= gimple_build_call (decl
, 0);
3440 gimple_set_location (g
, gimple_location (stmt
));
3441 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
3444 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3445 x
= gimple_build_call (fn
, 1, var
);
3446 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3449 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3452 gsi_remove (&gsi
, true);
3459 const pass_data pass_data_lower_resx
=
3461 GIMPLE_PASS
, /* type */
3463 OPTGROUP_NONE
, /* optinfo_flags */
3464 TV_TREE_EH
, /* tv_id */
3465 PROP_gimple_lcf
, /* properties_required */
3466 0, /* properties_provided */
3467 0, /* properties_destroyed */
3468 0, /* todo_flags_start */
3469 0, /* todo_flags_finish */
3472 class pass_lower_resx
: public gimple_opt_pass
3475 pass_lower_resx (gcc::context
*ctxt
)
3476 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3479 /* opt_pass methods: */
3480 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3481 virtual unsigned int execute (function
*);
3483 }; // class pass_lower_resx
3486 pass_lower_resx::execute (function
*fun
)
3489 bool dominance_invalidated
= false;
3490 bool any_rewritten
= false;
3492 hash_map
<eh_region
, tree
> mnt_map
;
3494 FOR_EACH_BB_FN (bb
, fun
)
3496 gimple
*last
= last_stmt (bb
);
3497 if (last
&& is_gimple_resx (last
))
3499 dominance_invalidated
|=
3500 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3501 any_rewritten
= true;
3505 if (dominance_invalidated
)
3507 free_dominance_info (CDI_DOMINATORS
);
3508 free_dominance_info (CDI_POST_DOMINATORS
);
3511 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3517 make_pass_lower_resx (gcc::context
*ctxt
)
3519 return new pass_lower_resx (ctxt
);
3522 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3526 optimize_clobbers (basic_block bb
)
3528 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3529 bool any_clobbers
= false;
3530 bool seen_stack_restore
= false;
3534 /* Only optimize anything if the bb contains at least one clobber,
3535 ends with resx (checked by caller), optionally contains some
3536 debug stmts or labels, or at most one __builtin_stack_restore
3537 call, and has an incoming EH edge. */
3538 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3540 gimple
*stmt
= gsi_stmt (gsi
);
3541 if (is_gimple_debug (stmt
))
3543 if (gimple_clobber_p (stmt
))
3545 any_clobbers
= true;
3548 if (!seen_stack_restore
3549 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3551 seen_stack_restore
= true;
3554 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3560 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3561 if (e
->flags
& EDGE_EH
)
3565 gsi
= gsi_last_bb (bb
);
3566 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3568 gimple
*stmt
= gsi_stmt (gsi
);
3569 if (!gimple_clobber_p (stmt
))
3571 unlink_stmt_vdef (stmt
);
3572 gsi_remove (&gsi
, true);
3573 release_defs (stmt
);
3577 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3578 internal throw to successor BB.
3579 SUNK, if not NULL, is an array of sequences indexed by basic-block
3580 index to sink to and to pick up sinking opportunities from.
3581 If FOUND_OPPORTUNITY is not NULL then do not perform the optimization
3582 but set *FOUND_OPPORTUNITY to true. */
3585 sink_clobbers (basic_block bb
,
3586 gimple_seq
*sunk
= NULL
, bool *found_opportunity
= NULL
)
3590 gimple_stmt_iterator gsi
, dgsi
;
3592 bool any_clobbers
= false;
3595 /* Only optimize if BB has a single EH successor and
3596 all predecessor edges are EH too. */
3597 if (!single_succ_p (bb
)
3598 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3601 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3603 if ((e
->flags
& EDGE_EH
) == 0)
3607 /* And BB contains only CLOBBER stmts before the final
3609 gsi
= gsi_last_bb (bb
);
3610 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3612 gimple
*stmt
= gsi_stmt (gsi
);
3613 if (is_gimple_debug (stmt
))
3615 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3617 if (!gimple_clobber_p (stmt
))
3619 any_clobbers
= true;
3621 if (!any_clobbers
&& (!sunk
|| gimple_seq_empty_p (sunk
[bb
->index
])))
3624 /* If this was a dry run, tell it we found clobbers to sink. */
3625 if (found_opportunity
)
3627 *found_opportunity
= true;
3631 edge succe
= single_succ_edge (bb
);
3632 succbb
= succe
->dest
;
3634 /* See if there is a virtual PHI node to take an updated virtual
3637 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3638 !gsi_end_p (gpi
); gsi_next (&gpi
))
3640 tree res
= gimple_phi_result (gpi
.phi ());
3641 if (virtual_operand_p (res
))
3648 gimple
*first_sunk
= NULL
;
3649 gimple
*last_sunk
= NULL
;
3650 if (sunk
&& !(succbb
->flags
& BB_VISITED
))
3651 dgsi
= gsi_start (sunk
[succbb
->index
]);
3653 dgsi
= gsi_after_labels (succbb
);
3654 gsi
= gsi_last_bb (bb
);
3655 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3657 gimple
*stmt
= gsi_stmt (gsi
);
3659 if (is_gimple_debug (stmt
))
3661 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3663 lhs
= gimple_assign_lhs (stmt
);
3664 /* Unfortunately we don't have dominance info updated at this
3665 point, so checking if
3666 dominated_by_p (CDI_DOMINATORS, succbb,
3667 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3668 would be too costly. Thus, avoid sinking any clobbers that
3669 refer to non-(D) SSA_NAMEs. */
3670 if (TREE_CODE (lhs
) == MEM_REF
3671 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3672 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3674 unlink_stmt_vdef (stmt
);
3675 gsi_remove (&gsi
, true);
3676 release_defs (stmt
);
3680 /* As we do not change stmt order when sinking across a
3681 forwarder edge we can keep virtual operands in place. */
3682 gsi_remove (&gsi
, false);
3683 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3688 if (sunk
&& !gimple_seq_empty_p (sunk
[bb
->index
]))
3691 first_sunk
= gsi_stmt (gsi_last (sunk
[bb
->index
]));
3692 last_sunk
= gsi_stmt (gsi_start (sunk
[bb
->index
]));
3693 gsi_insert_seq_before_without_update (&dgsi
,
3694 sunk
[bb
->index
], GSI_NEW_STMT
);
3695 sunk
[bb
->index
] = NULL
;
3699 /* Adjust virtual operands if we sunk across a virtual PHI. */
3702 imm_use_iterator iter
;
3703 use_operand_p use_p
;
3705 tree phi_def
= gimple_phi_result (vphi
);
3706 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, phi_def
)
3707 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3708 SET_USE (use_p
, gimple_vdef (first_sunk
));
3709 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (phi_def
))
3711 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (first_sunk
)) = 1;
3712 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (phi_def
) = 0;
3714 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
),
3715 gimple_vuse (last_sunk
));
3716 SET_USE (gimple_vuse_op (last_sunk
), phi_def
);
3718 /* If there isn't a single predecessor but no virtual PHI node
3719 arrange for virtual operands to be renamed. */
3720 else if (!single_pred_p (succbb
)
3721 && TREE_CODE (gimple_vuse (last_sunk
)) == SSA_NAME
)
3723 mark_virtual_operand_for_renaming (gimple_vuse (last_sunk
));
3724 todo
|= TODO_update_ssa_only_virtuals
;
3731 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3732 we have found some duplicate labels and removed some edges. */
3735 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3737 gimple_stmt_iterator gsi
;
3742 bool redirected
= false;
3744 region_nr
= gimple_eh_dispatch_region (stmt
);
3745 r
= get_eh_region_from_number (region_nr
);
3747 gsi
= gsi_last_bb (src
);
3753 auto_vec
<tree
> labels
;
3754 tree default_label
= NULL
;
3758 hash_set
<tree
> seen_values
;
3760 /* Collect the labels for a switch. Zero the post_landing_pad
3761 field becase we'll no longer have anything keeping these labels
3762 in existence and the optimizer will be free to merge these
3764 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3766 tree tp_node
, flt_node
, lab
= c
->label
;
3767 bool have_label
= false;
3770 tp_node
= c
->type_list
;
3771 flt_node
= c
->filter_list
;
3773 if (tp_node
== NULL
)
3775 default_label
= lab
;
3780 /* Filter out duplicate labels that arise when this handler
3781 is shadowed by an earlier one. When no labels are
3782 attached to the handler anymore, we remove
3783 the corresponding edge and then we delete unreachable
3784 blocks at the end of this pass. */
3785 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3787 tree t
= build_case_label (TREE_VALUE (flt_node
),
3789 labels
.safe_push (t
);
3790 seen_values
.add (TREE_VALUE (flt_node
));
3794 tp_node
= TREE_CHAIN (tp_node
);
3795 flt_node
= TREE_CHAIN (flt_node
);
3800 remove_edge (find_edge (src
, label_to_block (cfun
, lab
)));
3805 /* Clean up the edge flags. */
3806 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3808 if (e
->flags
& EDGE_FALLTHRU
)
3810 /* If there was no catch-all, use the fallthru edge. */
3811 if (default_label
== NULL
)
3812 default_label
= gimple_block_label (e
->dest
);
3813 e
->flags
&= ~EDGE_FALLTHRU
;
3816 gcc_assert (default_label
!= NULL
);
3818 /* Don't generate a switch if there's only a default case.
3819 This is common in the form of try { A; } catch (...) { B; }. */
3820 if (!labels
.exists ())
3822 e
= single_succ_edge (src
);
3823 e
->flags
|= EDGE_FALLTHRU
;
3827 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3828 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3830 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3831 filter
= make_ssa_name (filter
, x
);
3832 gimple_call_set_lhs (x
, filter
);
3833 gimple_set_location (x
, gimple_location (stmt
));
3834 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3836 /* Turn the default label into a default case. */
3837 default_label
= build_case_label (NULL
, NULL
, default_label
);
3838 sort_case_labels (labels
);
3840 x
= gimple_build_switch (filter
, default_label
, labels
);
3841 gimple_set_location (x
, gimple_location (stmt
));
3842 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3847 case ERT_ALLOWED_EXCEPTIONS
:
3849 edge b_e
= BRANCH_EDGE (src
);
3850 edge f_e
= FALLTHRU_EDGE (src
);
3852 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3853 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3855 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3856 filter
= make_ssa_name (filter
, x
);
3857 gimple_call_set_lhs (x
, filter
);
3858 gimple_set_location (x
, gimple_location (stmt
));
3859 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3861 r
->u
.allowed
.label
= NULL
;
3862 x
= gimple_build_cond (EQ_EXPR
, filter
,
3863 build_int_cst (TREE_TYPE (filter
),
3864 r
->u
.allowed
.filter
),
3865 NULL_TREE
, NULL_TREE
);
3866 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3868 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3869 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3877 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3878 gsi_remove (&gsi
, true);
3884 const pass_data pass_data_lower_eh_dispatch
=
3886 GIMPLE_PASS
, /* type */
3887 "ehdisp", /* name */
3888 OPTGROUP_NONE
, /* optinfo_flags */
3889 TV_TREE_EH
, /* tv_id */
3890 PROP_gimple_lcf
, /* properties_required */
3891 0, /* properties_provided */
3892 0, /* properties_destroyed */
3893 0, /* todo_flags_start */
3894 0, /* todo_flags_finish */
3897 class pass_lower_eh_dispatch
: public gimple_opt_pass
3900 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3901 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3904 /* opt_pass methods: */
3905 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3906 virtual unsigned int execute (function
*);
3908 }; // class pass_lower_eh_dispatch
3911 pass_lower_eh_dispatch::execute (function
*fun
)
3915 bool redirected
= false;
3916 bool any_resx_to_process
= false;
3918 assign_filter_values ();
3920 FOR_EACH_BB_FN (bb
, fun
)
3922 gimple
*last
= last_stmt (bb
);
3925 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3927 redirected
|= lower_eh_dispatch (bb
,
3928 as_a
<geh_dispatch
*> (last
));
3929 flags
|= TODO_update_ssa_only_virtuals
;
3931 else if (gimple_code (last
) == GIMPLE_RESX
)
3933 if (stmt_can_throw_external (fun
, last
))
3934 optimize_clobbers (bb
);
3935 else if (!any_resx_to_process
)
3936 sink_clobbers (bb
, NULL
, &any_resx_to_process
);
3938 bb
->flags
&= ~BB_VISITED
;
3942 free_dominance_info (CDI_DOMINATORS
);
3943 delete_unreachable_blocks ();
3946 if (any_resx_to_process
)
3948 /* Make sure to catch all secondary sinking opportunities by processing
3949 blocks in RPO order and after all CFG modifications from lowering
3950 and unreachable block removal. */
3951 int *rpo
= XNEWVEC (int, n_basic_blocks_for_fn (fun
));
3952 int rpo_n
= pre_and_rev_post_order_compute_fn (fun
, NULL
, rpo
, false);
3953 gimple_seq
*sunk
= XCNEWVEC (gimple_seq
, last_basic_block_for_fn (fun
));
3954 for (int i
= 0; i
< rpo_n
; ++i
)
3956 bb
= BASIC_BLOCK_FOR_FN (fun
, rpo
[i
]);
3957 gimple
*last
= last_stmt (bb
);
3959 && gimple_code (last
) == GIMPLE_RESX
3960 && !stmt_can_throw_external (fun
, last
))
3961 flags
|= sink_clobbers (bb
, sunk
);
3962 /* If there were any clobbers sunk into this BB, insert them now. */
3963 if (!gimple_seq_empty_p (sunk
[bb
->index
]))
3965 gimple_stmt_iterator gsi
= gsi_after_labels (bb
);
3966 gsi_insert_seq_before (&gsi
, sunk
[bb
->index
], GSI_NEW_STMT
);
3967 sunk
[bb
->index
] = NULL
;
3969 bb
->flags
|= BB_VISITED
;
3981 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3983 return new pass_lower_eh_dispatch (ctxt
);
3986 /* Walk statements, see what regions and, optionally, landing pads
3987 are really referenced.
3989 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3990 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3992 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3995 The caller is responsible for freeing the returned sbitmaps. */
3998 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
4000 sbitmap r_reachable
, lp_reachable
;
4002 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
4003 gcc_checking_assert (r_reachablep
!= NULL
);
4005 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
4006 bitmap_clear (r_reachable
);
4007 *r_reachablep
= r_reachable
;
4009 if (mark_landing_pads
)
4011 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
4012 bitmap_clear (lp_reachable
);
4013 *lp_reachablep
= lp_reachable
;
4016 lp_reachable
= NULL
;
4018 FOR_EACH_BB_FN (bb
, cfun
)
4020 gimple_stmt_iterator gsi
;
4022 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4024 gimple
*stmt
= gsi_stmt (gsi
);
4026 if (mark_landing_pads
)
4028 int lp_nr
= lookup_stmt_eh_lp (stmt
);
4030 /* Negative LP numbers are MUST_NOT_THROW regions which
4031 are not considered BB enders. */
4033 bitmap_set_bit (r_reachable
, -lp_nr
);
4035 /* Positive LP numbers are real landing pads, and BB enders. */
4038 gcc_assert (gsi_one_before_end_p (gsi
));
4039 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
4040 bitmap_set_bit (r_reachable
, region
->index
);
4041 bitmap_set_bit (lp_reachable
, lp_nr
);
4045 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
4046 switch (gimple_code (stmt
))
4049 bitmap_set_bit (r_reachable
,
4050 gimple_resx_region (as_a
<gresx
*> (stmt
)));
4052 case GIMPLE_EH_DISPATCH
:
4053 bitmap_set_bit (r_reachable
,
4054 gimple_eh_dispatch_region (
4055 as_a
<geh_dispatch
*> (stmt
)));
4058 if (gimple_call_builtin_p (stmt
, BUILT_IN_EH_COPY_VALUES
))
4059 for (int i
= 0; i
< 2; ++i
)
4061 tree rt
= gimple_call_arg (stmt
, i
);
4062 HOST_WIDE_INT ri
= tree_to_shwi (rt
);
4064 gcc_assert (ri
== (int)ri
);
4065 bitmap_set_bit (r_reachable
, ri
);
4075 /* Remove unreachable handlers and unreachable landing pads. */
4078 remove_unreachable_handlers (void)
4080 sbitmap r_reachable
, lp_reachable
;
4085 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
4089 fprintf (dump_file
, "Before removal of unreachable regions:\n");
4090 dump_eh_tree (dump_file
, cfun
);
4091 fprintf (dump_file
, "Reachable regions: ");
4092 dump_bitmap_file (dump_file
, r_reachable
);
4093 fprintf (dump_file
, "Reachable landing pads: ");
4094 dump_bitmap_file (dump_file
, lp_reachable
);
4099 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
4100 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
4102 "Removing unreachable region %d\n",
4106 remove_unreachable_eh_regions (r_reachable
);
4108 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
4109 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
4113 "Removing unreachable landing pad %d\n",
4115 remove_eh_landing_pad (lp
);
4120 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
4121 dump_eh_tree (dump_file
, cfun
);
4122 fprintf (dump_file
, "\n\n");
4125 sbitmap_free (r_reachable
);
4126 sbitmap_free (lp_reachable
);
4129 verify_eh_tree (cfun
);
4132 /* Remove unreachable handlers if any landing pads have been removed after
4133 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
4136 maybe_remove_unreachable_handlers (void)
4141 if (cfun
->eh
== NULL
)
4144 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
4146 && (lp
->post_landing_pad
== NULL_TREE
4147 || label_to_block (cfun
, lp
->post_landing_pad
) == NULL
))
4149 remove_unreachable_handlers ();
4154 /* Remove regions that do not have landing pads. This assumes
4155 that remove_unreachable_handlers has already been run, and
4156 that we've just manipulated the landing pads since then.
4158 Preserve regions with landing pads and regions that prevent
4159 exceptions from propagating further, even if these regions
4160 are not reachable. */
4163 remove_unreachable_handlers_no_lp (void)
4166 sbitmap r_reachable
;
4169 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
4171 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
4176 if (region
->landing_pads
!= NULL
4177 || region
->type
== ERT_MUST_NOT_THROW
)
4178 bitmap_set_bit (r_reachable
, region
->index
);
4181 && !bitmap_bit_p (r_reachable
, region
->index
))
4183 "Removing unreachable region %d\n",
4187 remove_unreachable_eh_regions (r_reachable
);
4189 sbitmap_free (r_reachable
);
4192 /* Undo critical edge splitting on an EH landing pad. Earlier, we
4193 optimisticaly split all sorts of edges, including EH edges. The
4194 optimization passes in between may not have needed them; if not,
4195 we should undo the split.
4197 Recognize this case by having one EH edge incoming to the BB and
4198 one normal edge outgoing; BB should be empty apart from the
4199 post_landing_pad label.
4201 Note that this is slightly different from the empty handler case
4202 handled by cleanup_empty_eh, in that the actual handler may yet
4203 have actual code but the landing pad has been separated from the
4204 handler. As such, cleanup_empty_eh relies on this transformation
4205 having been done first. */
4208 unsplit_eh (eh_landing_pad lp
)
4210 basic_block bb
= label_to_block (cfun
, lp
->post_landing_pad
);
4211 gimple_stmt_iterator gsi
;
4214 /* Quickly check the edge counts on BB for singularity. */
4215 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4217 e_in
= single_pred_edge (bb
);
4218 e_out
= single_succ_edge (bb
);
4220 /* Input edge must be EH and output edge must be normal. */
4221 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4224 /* The block must be empty except for the labels and debug insns. */
4225 gsi
= gsi_after_labels (bb
);
4226 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4227 gsi_next_nondebug (&gsi
);
4228 if (!gsi_end_p (gsi
))
4231 /* The destination block must not already have a landing pad
4232 for a different region. */
4233 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4235 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4241 lab
= gimple_label_label (label_stmt
);
4242 lp_nr
= EH_LANDING_PAD_NR (lab
);
4243 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4247 /* The new destination block must not already be a destination of
4248 the source block, lest we merge fallthru and eh edges and get
4249 all sorts of confused. */
4250 if (find_edge (e_in
->src
, e_out
->dest
))
4253 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4254 thought this should have been cleaned up by a phicprop pass, but
4255 that doesn't appear to handle virtuals. Propagate by hand. */
4256 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4258 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4261 gphi
*phi
= gpi
.phi ();
4262 tree lhs
= gimple_phi_result (phi
);
4263 tree rhs
= gimple_phi_arg_def (phi
, 0);
4264 use_operand_p use_p
;
4265 imm_use_iterator iter
;
4267 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4269 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4270 SET_USE (use_p
, rhs
);
4273 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4274 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4276 remove_phi_node (&gpi
, true);
4280 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4281 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4282 lp
->index
, e_out
->dest
->index
);
4284 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4285 a successor edge, humor it. But do the real CFG change with the
4286 predecessor of E_OUT in order to preserve the ordering of arguments
4287 to the PHI nodes in E_OUT->DEST. */
4288 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4289 redirect_edge_pred (e_out
, e_in
->src
);
4290 e_out
->flags
= e_in
->flags
;
4291 e_out
->probability
= e_in
->probability
;
4297 /* Examine each landing pad block and see if it matches unsplit_eh. */
4300 unsplit_all_eh (void)
4302 bool changed
= false;
4306 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4308 changed
|= unsplit_eh (lp
);
4313 /* Wrapper around unsplit_all_eh that makes it usable everywhere. */
4316 unsplit_eh_edges (void)
4320 /* unsplit_all_eh can die looking up unreachable landing pads. */
4321 maybe_remove_unreachable_handlers ();
4323 changed
= unsplit_all_eh ();
4325 /* If EH edges have been unsplit, delete unreachable forwarder blocks. */
4328 free_dominance_info (CDI_DOMINATORS
);
4329 free_dominance_info (CDI_POST_DOMINATORS
);
4330 delete_unreachable_blocks ();
4334 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4335 to OLD_BB to NEW_BB; return true on success, false on failure.
4337 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4338 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4339 Virtual PHIs may be deleted and marked for renaming. */
4342 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4343 edge old_bb_out
, bool change_region
)
4345 gphi_iterator ngsi
, ogsi
;
4348 bitmap ophi_handled
;
4350 /* The destination block must not be a regular successor for any
4351 of the preds of the landing pad. Thus, avoid turning
4361 which CFG verification would choke on. See PR45172 and PR51089. */
4362 if (!single_pred_p (new_bb
))
4363 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4364 if (find_edge (e
->src
, new_bb
))
4367 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4368 redirect_edge_var_map_clear (e
);
4370 ophi_handled
= BITMAP_ALLOC (NULL
);
4372 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4373 for the edges we're going to move. */
4374 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4376 gphi
*ophi
, *nphi
= ngsi
.phi ();
4379 nresult
= gimple_phi_result (nphi
);
4380 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4382 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4383 the source ssa_name. */
4385 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4388 if (gimple_phi_result (ophi
) == nop
)
4393 /* If we did find the corresponding PHI, copy those inputs. */
4396 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4397 if (!has_single_use (nop
))
4399 imm_use_iterator imm_iter
;
4400 use_operand_p use_p
;
4402 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4404 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4405 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4406 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4410 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4411 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4416 if ((e
->flags
& EDGE_EH
) == 0)
4418 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4419 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4420 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4423 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4424 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4425 variable is unchanged from input to the block and we can simply
4426 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4430 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4431 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4432 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4436 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4437 we don't know what values from the other edges into NEW_BB to use. */
4438 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4440 gphi
*ophi
= ogsi
.phi ();
4441 tree oresult
= gimple_phi_result (ophi
);
4442 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4446 /* Finally, move the edges and update the PHIs. */
4447 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4448 if (e
->flags
& EDGE_EH
)
4450 /* ??? CFG manipluation routines do not try to update loop
4451 form on edge redirection. Do so manually here for now. */
4452 /* If we redirect a loop entry or latch edge that will either create
4453 a multiple entry loop or rotate the loop. If the loops merge
4454 we may have created a loop with multiple latches.
4455 All of this isn't easily fixed thus cancel the affected loop
4456 and mark the other loop as possibly having multiple latches. */
4457 if (e
->dest
== e
->dest
->loop_father
->header
)
4459 mark_loop_for_removal (e
->dest
->loop_father
);
4460 new_bb
->loop_father
->latch
= NULL
;
4461 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4463 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4464 redirect_edge_succ (e
, new_bb
);
4465 flush_pending_stmts (e
);
4470 BITMAP_FREE (ophi_handled
);
4474 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4475 redirect_edge_var_map_clear (e
);
4476 BITMAP_FREE (ophi_handled
);
4480 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4481 old region to NEW_REGION at BB. */
4484 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4485 eh_landing_pad lp
, eh_region new_region
)
4487 gimple_stmt_iterator gsi
;
4490 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4494 lp
->region
= new_region
;
4495 lp
->next_lp
= new_region
->landing_pads
;
4496 new_region
->landing_pads
= lp
;
4498 /* Delete the RESX that was matched within the empty handler block. */
4499 gsi
= gsi_last_bb (bb
);
4500 unlink_stmt_vdef (gsi_stmt (gsi
));
4501 gsi_remove (&gsi
, true);
4503 /* Clean up E_OUT for the fallthru. */
4504 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4505 e_out
->probability
= profile_probability::always ();
4508 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4509 unsplitting than unsplit_eh was prepared to handle, e.g. when
4510 multiple incoming edges and phis are involved. */
4513 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4515 gimple_stmt_iterator gsi
;
4518 /* We really ought not have totally lost everything following
4519 a landing pad label. Given that BB is empty, there had better
4521 gcc_assert (e_out
!= NULL
);
4523 /* The destination block must not already have a landing pad
4524 for a different region. */
4526 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4528 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4533 lab
= gimple_label_label (stmt
);
4534 lp_nr
= EH_LANDING_PAD_NR (lab
);
4535 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4539 /* Attempt to move the PHIs into the successor block. */
4540 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4542 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4544 "Unsplit EH landing pad %d to block %i "
4545 "(via cleanup_empty_eh).\n",
4546 lp
->index
, e_out
->dest
->index
);
4553 /* Return true if edge E_FIRST is part of an empty infinite loop
4554 or leads to such a loop through a series of single successor
4558 infinite_empty_loop_p (edge e_first
)
4560 bool inf_loop
= false;
4563 if (e_first
->dest
== e_first
->src
)
4566 e_first
->src
->aux
= (void *) 1;
4567 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4569 gimple_stmt_iterator gsi
;
4575 e
->dest
->aux
= (void *) 1;
4576 gsi
= gsi_after_labels (e
->dest
);
4577 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4578 gsi_next_nondebug (&gsi
);
4579 if (!gsi_end_p (gsi
))
4582 e_first
->src
->aux
= NULL
;
4583 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4584 e
->dest
->aux
= NULL
;
4589 /* Examine the block associated with LP to determine if it's an empty
4590 handler for its EH region. If so, attempt to redirect EH edges to
4591 an outer region. Return true the CFG was updated in any way. This
4592 is similar to jump forwarding, just across EH edges. */
4595 cleanup_empty_eh (eh_landing_pad lp
)
4597 basic_block bb
= label_to_block (cfun
, lp
->post_landing_pad
);
4598 gimple_stmt_iterator gsi
;
4600 eh_region new_region
;
4603 bool has_non_eh_pred
;
4607 /* There can be zero or one edges out of BB. This is the quickest test. */
4608 switch (EDGE_COUNT (bb
->succs
))
4614 e_out
= single_succ_edge (bb
);
4620 gsi
= gsi_last_nondebug_bb (bb
);
4621 resx
= gsi_stmt (gsi
);
4622 if (resx
&& is_gimple_resx (resx
))
4624 if (stmt_can_throw_external (cfun
, resx
))
4625 optimize_clobbers (bb
);
4626 else if (sink_clobbers (bb
))
4630 gsi
= gsi_after_labels (bb
);
4632 /* Make sure to skip debug statements. */
4633 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4634 gsi_next_nondebug (&gsi
);
4636 /* If the block is totally empty, look for more unsplitting cases. */
4637 if (gsi_end_p (gsi
))
4639 /* For the degenerate case of an infinite loop bail out.
4640 If bb has no successors and is totally empty, which can happen e.g.
4641 because of incorrect noreturn attribute, bail out too. */
4643 || infinite_empty_loop_p (e_out
))
4646 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4649 /* The block should consist only of a single RESX statement, modulo a
4650 preceding call to __builtin_stack_restore if there is no outgoing
4651 edge, since the call can be eliminated in this case. */
4652 resx
= gsi_stmt (gsi
);
4653 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4655 gsi_next_nondebug (&gsi
);
4656 resx
= gsi_stmt (gsi
);
4658 if (!is_gimple_resx (resx
))
4660 gcc_assert (gsi_one_nondebug_before_end_p (gsi
));
4662 /* Determine if there are non-EH edges, or resx edges into the handler. */
4663 has_non_eh_pred
= false;
4664 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4665 if (!(e
->flags
& EDGE_EH
))
4666 has_non_eh_pred
= true;
4668 /* Find the handler that's outer of the empty handler by looking at
4669 where the RESX instruction was vectored. */
4670 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4671 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4673 /* If there's no destination region within the current function,
4674 redirection is trivial via removing the throwing statements from
4675 the EH region, removing the EH edges, and allowing the block
4676 to go unreachable. */
4677 if (new_region
== NULL
)
4679 gcc_assert (e_out
== NULL
);
4680 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4681 if (e
->flags
& EDGE_EH
)
4683 gimple
*stmt
= last_stmt (e
->src
);
4684 remove_stmt_from_eh_lp (stmt
);
4692 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4693 to handle the abort and allow the blocks to go unreachable. */
4694 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4696 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4697 if (e
->flags
& EDGE_EH
)
4699 gimple
*stmt
= last_stmt (e
->src
);
4700 remove_stmt_from_eh_lp (stmt
);
4701 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4709 /* Try to redirect the EH edges and merge the PHIs into the destination
4710 landing pad block. If the merge succeeds, we'll already have redirected
4711 all the EH edges. The handler itself will go unreachable if there were
4713 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4716 /* Finally, if all input edges are EH edges, then we can (potentially)
4717 reduce the number of transfers from the runtime by moving the landing
4718 pad from the original region to the new region. This is a win when
4719 we remove the last CLEANUP region along a particular exception
4720 propagation path. Since nothing changes except for the region with
4721 which the landing pad is associated, the PHI nodes do not need to be
4723 if (!has_non_eh_pred
)
4725 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4726 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4727 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4728 lp
->index
, new_region
->index
);
4730 /* ??? The CFG didn't change, but we may have rendered the
4731 old EH region unreachable. Trigger a cleanup there. */
4738 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4739 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4740 remove_eh_landing_pad (lp
);
4744 /* Do a post-order traversal of the EH region tree. Examine each
4745 post_landing_pad block and see if we can eliminate it as empty. */
4748 cleanup_all_empty_eh (void)
4750 bool changed
= false;
4754 /* Ideally we'd walk the region tree and process LPs inner to outer
4755 to avoid quadraticness in EH redirection. Walking the LP array
4756 in reverse seems to be an approximation of that. */
4757 for (i
= vec_safe_length (cfun
->eh
->lp_array
) - 1; i
>= 1; --i
)
4759 lp
= (*cfun
->eh
->lp_array
)[i
];
4761 changed
|= cleanup_empty_eh (lp
);
4767 /* Perform cleanups and lowering of exception handling
4768 1) cleanups regions with handlers doing nothing are optimized out
4769 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4770 3) Info about regions that are containing instructions, and regions
4771 reachable via local EH edges is collected
4772 4) Eh tree is pruned for regions no longer necessary.
4774 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4775 Unify those that have the same failure decl and locus.
4779 execute_cleanup_eh_1 (void)
4781 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4782 looking up unreachable landing pads. */
4783 remove_unreachable_handlers ();
4785 /* Watch out for the region tree vanishing due to all unreachable. */
4786 if (cfun
->eh
->region_tree
)
4788 bool changed
= false;
4791 changed
|= unsplit_all_eh ();
4792 changed
|= cleanup_all_empty_eh ();
4796 free_dominance_info (CDI_DOMINATORS
);
4797 free_dominance_info (CDI_POST_DOMINATORS
);
4799 /* We delayed all basic block deletion, as we may have performed
4800 cleanups on EH edges while non-EH edges were still present. */
4801 delete_unreachable_blocks ();
4803 /* We manipulated the landing pads. Remove any region that no
4804 longer has a landing pad. */
4805 remove_unreachable_handlers_no_lp ();
4807 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4816 const pass_data pass_data_cleanup_eh
=
4818 GIMPLE_PASS
, /* type */
4819 "ehcleanup", /* name */
4820 OPTGROUP_NONE
, /* optinfo_flags */
4821 TV_TREE_EH
, /* tv_id */
4822 PROP_gimple_lcf
, /* properties_required */
4823 0, /* properties_provided */
4824 0, /* properties_destroyed */
4825 0, /* todo_flags_start */
4826 0, /* todo_flags_finish */
4829 class pass_cleanup_eh
: public gimple_opt_pass
4832 pass_cleanup_eh (gcc::context
*ctxt
)
4833 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4836 /* opt_pass methods: */
4837 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4838 virtual bool gate (function
*fun
)
4840 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4843 virtual unsigned int execute (function
*);
4845 }; // class pass_cleanup_eh
4848 pass_cleanup_eh::execute (function
*fun
)
4850 int ret
= execute_cleanup_eh_1 ();
4852 /* If the function no longer needs an EH personality routine
4853 clear it. This exposes cross-language inlining opportunities
4854 and avoids references to a never defined personality routine. */
4855 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4856 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4857 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4865 make_pass_cleanup_eh (gcc::context
*ctxt
)
4867 return new pass_cleanup_eh (ctxt
);
4870 /* Disable warnings about missing quoting in GCC diagnostics for
4871 the verification errors. Their format strings don't follow GCC
4872 diagnostic conventions but are only used for debugging. */
4874 # pragma GCC diagnostic push
4875 # pragma GCC diagnostic ignored "-Wformat-diag"
4878 /* Verify that BB containing STMT as the last statement, has precisely the
4879 edge that make_eh_edges would create. */
4882 verify_eh_edges (gimple
*stmt
)
4884 basic_block bb
= gimple_bb (stmt
);
4885 eh_landing_pad lp
= NULL
;
4890 lp_nr
= lookup_stmt_eh_lp (stmt
);
4892 lp
= get_eh_landing_pad_from_number (lp_nr
);
4895 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4897 if (e
->flags
& EDGE_EH
)
4901 error ("BB %i has multiple EH edges", bb
->index
);
4913 error ("BB %i cannot throw but has an EH edge", bb
->index
);
4919 if (!stmt_could_throw_p (cfun
, stmt
))
4921 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4925 if (eh_edge
== NULL
)
4927 error ("BB %i is missing an EH edge", bb
->index
);
4931 if (eh_edge
->dest
!= label_to_block (cfun
, lp
->post_landing_pad
))
4933 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4940 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4943 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4947 basic_block src
, dst
;
4948 bool want_fallthru
= true;
4952 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4953 src
= gimple_bb (stmt
);
4955 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4956 gcc_assert (e
->aux
== NULL
);
4961 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4963 dst
= label_to_block (cfun
, c
->label
);
4964 e
= find_edge (src
, dst
);
4967 error ("BB %i is missing an edge", src
->index
);
4972 /* A catch-all handler doesn't have a fallthru. */
4973 if (c
->type_list
== NULL
)
4975 want_fallthru
= false;
4981 case ERT_ALLOWED_EXCEPTIONS
:
4982 dst
= label_to_block (cfun
, r
->u
.allowed
.label
);
4983 e
= find_edge (src
, dst
);
4986 error ("BB %i is missing an edge", src
->index
);
4997 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4999 if (e
->flags
& EDGE_FALLTHRU
)
5001 if (fall_edge
!= NULL
)
5003 error ("BB %i too many fallthru edges", src
->index
);
5012 error ("BB %i has incorrect edge", src
->index
);
5016 if ((fall_edge
!= NULL
) ^ want_fallthru
)
5018 error ("BB %i has incorrect fallthru edge", src
->index
);
5026 # pragma GCC diagnostic pop