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 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2076 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2077 DECL_GIMPLE_REG_P (tmp
) = 1;
2078 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2080 /* Look for things that can throw exceptions, and record them. */
2081 if (state
->cur_region
&& stmt_could_throw_p (cfun
, stmt
))
2083 record_stmt_eh_region (state
->cur_region
, stmt
);
2084 note_eh_region_may_contain_throw (state
->cur_region
);
2091 maybe_record_in_goto_queue (state
, stmt
);
2095 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2100 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2101 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2102 replace
= lower_try_finally (state
, try_stmt
);
2105 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2108 replace
= gimple_try_eval (try_stmt
);
2109 lower_eh_constructs_1 (state
, &replace
);
2112 switch (gimple_code (x
))
2115 replace
= lower_catch (state
, try_stmt
);
2117 case GIMPLE_EH_FILTER
:
2118 replace
= lower_eh_filter (state
, try_stmt
);
2120 case GIMPLE_EH_MUST_NOT_THROW
:
2121 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2123 case GIMPLE_EH_ELSE
:
2124 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2127 replace
= lower_cleanup (state
, try_stmt
);
2133 /* Remove the old stmt and insert the transformed sequence
2135 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2136 gsi_remove (gsi
, true);
2138 /* Return since we don't want gsi_next () */
2141 case GIMPLE_EH_ELSE
:
2142 /* We should be eliminating this in lower_try_finally et al. */
2146 /* A type, a decl, or some kind of statement that we're not
2147 interested in. Don't walk them. */
2154 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2157 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2159 gimple_stmt_iterator gsi
;
2160 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2161 lower_eh_constructs_2 (state
, &gsi
);
2166 const pass_data pass_data_lower_eh
=
2168 GIMPLE_PASS
, /* type */
2170 OPTGROUP_NONE
, /* optinfo_flags */
2171 TV_TREE_EH
, /* tv_id */
2172 PROP_gimple_lcf
, /* properties_required */
2173 PROP_gimple_leh
, /* properties_provided */
2174 0, /* properties_destroyed */
2175 0, /* todo_flags_start */
2176 0, /* todo_flags_finish */
2179 class pass_lower_eh
: public gimple_opt_pass
2182 pass_lower_eh (gcc::context
*ctxt
)
2183 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2186 /* opt_pass methods: */
2187 virtual unsigned int execute (function
*);
2189 }; // class pass_lower_eh
2192 pass_lower_eh::execute (function
*fun
)
2194 struct leh_state null_state
;
2197 bodyp
= gimple_body (current_function_decl
);
2201 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2202 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2203 memset (&null_state
, 0, sizeof (null_state
));
2205 collect_finally_tree_1 (bodyp
, NULL
);
2206 lower_eh_constructs_1 (&null_state
, &bodyp
);
2207 gimple_set_body (current_function_decl
, bodyp
);
2209 /* We assume there's a return statement, or something, at the end of
2210 the function, and thus ploping the EH sequence afterward won't
2212 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2213 gimple_seq_add_seq (&bodyp
, eh_seq
);
2215 /* We assume that since BODYP already existed, adding EH_SEQ to it
2216 didn't change its value, and we don't have to re-set the function. */
2217 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2219 delete finally_tree
;
2220 finally_tree
= NULL
;
2221 BITMAP_FREE (eh_region_may_contain_throw_map
);
2224 /* If this function needs a language specific EH personality routine
2225 and the frontend didn't already set one do so now. */
2226 if (function_needs_eh_personality (fun
) == eh_personality_lang
2227 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2228 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2229 = lang_hooks
.eh_personality ();
2237 make_pass_lower_eh (gcc::context
*ctxt
)
2239 return new pass_lower_eh (ctxt
);
2242 /* Create the multiple edges from an EH_DISPATCH statement to all of
2243 the possible handlers for its EH region. Return true if there's
2244 no fallthru edge; false if there is. */
2247 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2251 basic_block src
, dst
;
2253 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2254 src
= gimple_bb (stmt
);
2259 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2261 dst
= label_to_block (cfun
, c
->label
);
2262 make_edge (src
, dst
, 0);
2264 /* A catch-all handler doesn't have a fallthru. */
2265 if (c
->type_list
== NULL
)
2270 case ERT_ALLOWED_EXCEPTIONS
:
2271 dst
= label_to_block (cfun
, r
->u
.allowed
.label
);
2272 make_edge (src
, dst
, 0);
2282 /* Create the single EH edge from STMT to its nearest landing pad,
2283 if there is such a landing pad within the current function. */
2286 make_eh_edges (gimple
*stmt
)
2288 basic_block src
, dst
;
2292 lp_nr
= lookup_stmt_eh_lp (stmt
);
2296 lp
= get_eh_landing_pad_from_number (lp_nr
);
2297 gcc_assert (lp
!= NULL
);
2299 src
= gimple_bb (stmt
);
2300 dst
= label_to_block (cfun
, lp
->post_landing_pad
);
2301 make_edge (src
, dst
, EDGE_EH
);
2304 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2305 do not actually perform the final edge redirection.
2307 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2308 we intend to change the destination EH region as well; this means
2309 EH_LANDING_PAD_NR must already be set on the destination block label.
2310 If false, we're being called from generic cfg manipulation code and we
2311 should preserve our place within the region tree. */
2314 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2316 eh_landing_pad old_lp
, new_lp
;
2319 int old_lp_nr
, new_lp_nr
;
2320 tree old_label
, new_label
;
2324 old_bb
= edge_in
->dest
;
2325 old_label
= gimple_block_label (old_bb
);
2326 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2327 gcc_assert (old_lp_nr
> 0);
2328 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2330 throw_stmt
= last_stmt (edge_in
->src
);
2331 gcc_checking_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2333 new_label
= gimple_block_label (new_bb
);
2335 /* Look for an existing region that might be using NEW_BB already. */
2336 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2339 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2340 gcc_assert (new_lp
);
2342 /* Unless CHANGE_REGION is true, the new and old landing pad
2343 had better be associated with the same EH region. */
2344 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2349 gcc_assert (!change_region
);
2352 /* Notice when we redirect the last EH edge away from OLD_BB. */
2353 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2354 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2359 /* NEW_LP already exists. If there are still edges into OLD_LP,
2360 there's nothing to do with the EH tree. If there are no more
2361 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2362 If CHANGE_REGION is true, then our caller is expecting to remove
2364 if (e
== NULL
&& !change_region
)
2365 remove_eh_landing_pad (old_lp
);
2369 /* No correct landing pad exists. If there are no more edges
2370 into OLD_LP, then we can simply re-use the existing landing pad.
2371 Otherwise, we have to create a new landing pad. */
2374 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2378 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2379 new_lp
->post_landing_pad
= new_label
;
2380 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2383 /* Maybe move the throwing statement to the new region. */
2384 if (old_lp
!= new_lp
)
2386 remove_stmt_from_eh_lp (throw_stmt
);
2387 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2391 /* Redirect EH edge E to NEW_BB. */
2394 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2396 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2397 return ssa_redirect_edge (edge_in
, new_bb
);
2400 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2401 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2402 The actual edge update will happen in the caller. */
2405 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2407 tree new_lab
= gimple_block_label (new_bb
);
2408 bool any_changed
= false;
2413 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2417 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2419 old_bb
= label_to_block (cfun
, c
->label
);
2420 if (old_bb
== e
->dest
)
2428 case ERT_ALLOWED_EXCEPTIONS
:
2429 old_bb
= label_to_block (cfun
, r
->u
.allowed
.label
);
2430 gcc_assert (old_bb
== e
->dest
);
2431 r
->u
.allowed
.label
= new_lab
;
2439 gcc_assert (any_changed
);
2442 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2445 operation_could_trap_helper_p (enum tree_code op
,
2456 case TRUNC_DIV_EXPR
:
2458 case FLOOR_DIV_EXPR
:
2459 case ROUND_DIV_EXPR
:
2460 case EXACT_DIV_EXPR
:
2462 case FLOOR_MOD_EXPR
:
2463 case ROUND_MOD_EXPR
:
2464 case TRUNC_MOD_EXPR
:
2469 return flag_trapping_math
;
2470 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2479 /* Some floating point comparisons may trap. */
2484 case UNORDERED_EXPR
:
2496 /* These operations don't trap with floating point. */
2502 /* ABSU_EXPR never traps. */
2508 /* Any floating arithmetic may trap. */
2509 if (fp_operation
&& flag_trapping_math
)
2517 /* Constructing an object cannot trap. */
2522 /* Whether *COND_EXPR can trap depends on whether the
2523 first argument can trap, so signal it as not handled.
2524 Whether lhs is floating or not doesn't matter. */
2529 /* Any floating arithmetic may trap. */
2530 if (fp_operation
&& flag_trapping_math
)
2538 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2539 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2540 type operands that may trap. If OP is a division operator, DIVISOR contains
2541 the value of the divisor. */
2544 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2547 bool honor_nans
= (fp_operation
&& flag_trapping_math
2548 && !flag_finite_math_only
);
2549 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2552 /* This function cannot tell whether or not COND_EXPR and VEC_COND_EXPR could
2553 trap, because that depends on the respective condition op. */
2554 gcc_assert (op
!= COND_EXPR
&& op
!= VEC_COND_EXPR
);
2556 if (TREE_CODE_CLASS (op
) != tcc_comparison
2557 && TREE_CODE_CLASS (op
) != tcc_unary
2558 && TREE_CODE_CLASS (op
) != tcc_binary
)
2561 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2562 honor_nans
, honor_snans
, divisor
,
2567 /* Returns true if it is possible to prove that the index of
2568 an array access REF (an ARRAY_REF expression) falls into the
2572 in_array_bounds_p (tree ref
)
2574 tree idx
= TREE_OPERAND (ref
, 1);
2577 if (TREE_CODE (idx
) != INTEGER_CST
)
2580 min
= array_ref_low_bound (ref
);
2581 max
= array_ref_up_bound (ref
);
2584 || TREE_CODE (min
) != INTEGER_CST
2585 || TREE_CODE (max
) != INTEGER_CST
)
2588 if (tree_int_cst_lt (idx
, min
)
2589 || tree_int_cst_lt (max
, idx
))
2595 /* Returns true if it is possible to prove that the range of
2596 an array access REF (an ARRAY_RANGE_REF expression) falls
2597 into the array bounds. */
2600 range_in_array_bounds_p (tree ref
)
2602 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2603 tree range_min
, range_max
, min
, max
;
2605 range_min
= TYPE_MIN_VALUE (domain_type
);
2606 range_max
= TYPE_MAX_VALUE (domain_type
);
2609 || TREE_CODE (range_min
) != INTEGER_CST
2610 || TREE_CODE (range_max
) != INTEGER_CST
)
2613 min
= array_ref_low_bound (ref
);
2614 max
= array_ref_up_bound (ref
);
2617 || TREE_CODE (min
) != INTEGER_CST
2618 || TREE_CODE (max
) != INTEGER_CST
)
2621 if (tree_int_cst_lt (range_min
, min
)
2622 || tree_int_cst_lt (max
, range_max
))
2628 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2629 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2630 This routine expects only GIMPLE lhs or rhs input. */
2633 tree_could_trap_p (tree expr
)
2635 enum tree_code code
;
2636 bool fp_operation
= false;
2637 bool honor_trapv
= false;
2638 tree t
, base
, div
= NULL_TREE
;
2643 /* In COND_EXPR and VEC_COND_EXPR only the condition may trap, but
2644 they won't appear as operands in GIMPLE form, so this is just for the
2645 GENERIC uses where it needs to recurse on the operands and so
2646 *COND_EXPR itself doesn't trap. */
2647 if (TREE_CODE (expr
) == COND_EXPR
|| TREE_CODE (expr
) == VEC_COND_EXPR
)
2650 code
= TREE_CODE (expr
);
2651 t
= TREE_TYPE (expr
);
2655 if (COMPARISON_CLASS_P (expr
))
2656 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2658 fp_operation
= FLOAT_TYPE_P (t
);
2659 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2662 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2663 div
= TREE_OPERAND (expr
, 1);
2664 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2674 case VIEW_CONVERT_EXPR
:
2675 case WITH_SIZE_EXPR
:
2676 expr
= TREE_OPERAND (expr
, 0);
2677 code
= TREE_CODE (expr
);
2680 case ARRAY_RANGE_REF
:
2681 base
= TREE_OPERAND (expr
, 0);
2682 if (tree_could_trap_p (base
))
2684 if (TREE_THIS_NOTRAP (expr
))
2686 return !range_in_array_bounds_p (expr
);
2689 base
= TREE_OPERAND (expr
, 0);
2690 if (tree_could_trap_p (base
))
2692 if (TREE_THIS_NOTRAP (expr
))
2694 return !in_array_bounds_p (expr
);
2696 case TARGET_MEM_REF
:
2698 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2699 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2701 if (TREE_THIS_NOTRAP (expr
))
2703 /* We cannot prove that the access is in-bounds when we have
2704 variable-index TARGET_MEM_REFs. */
2705 if (code
== TARGET_MEM_REF
2706 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2708 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2710 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2711 poly_offset_int off
= mem_ref_offset (expr
);
2712 if (maybe_lt (off
, 0))
2714 if (TREE_CODE (base
) == STRING_CST
)
2715 return maybe_le (TREE_STRING_LENGTH (base
), off
);
2716 tree size
= DECL_SIZE_UNIT (base
);
2717 if (size
== NULL_TREE
2718 || !poly_int_tree_p (size
)
2719 || maybe_le (wi::to_poly_offset (size
), off
))
2721 /* Now we are sure the first byte of the access is inside
2728 return !TREE_THIS_NOTRAP (expr
);
2731 return TREE_THIS_VOLATILE (expr
);
2734 t
= get_callee_fndecl (expr
);
2735 /* Assume that calls to weak functions may trap. */
2736 if (!t
|| !DECL_P (t
))
2739 return tree_could_trap_p (t
);
2743 /* Assume that accesses to weak functions may trap, unless we know
2744 they are certainly defined in current TU or in some other
2746 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2748 cgraph_node
*node
= cgraph_node::get (expr
);
2750 node
= node
->function_symbol ();
2751 return !(node
&& node
->in_other_partition
);
2756 /* Assume that accesses to weak vars may trap, unless we know
2757 they are certainly defined in current TU or in some other
2759 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2761 varpool_node
*node
= varpool_node::get (expr
);
2763 node
= node
->ultimate_alias_target ();
2764 return !(node
&& node
->in_other_partition
);
2773 /* Return non-NULL if there is an integer operation with trapping overflow
2774 we can rewrite into non-trapping. Called via walk_tree from
2775 rewrite_to_non_trapping_overflow. */
2778 find_trapping_overflow (tree
*tp
, int *walk_subtrees
, void *data
)
2781 && ANY_INTEGRAL_TYPE_P (TREE_TYPE (*tp
))
2782 && !operation_no_trapping_overflow (TREE_TYPE (*tp
), TREE_CODE (*tp
)))
2784 if (IS_TYPE_OR_DECL_P (*tp
)
2785 || (TREE_CODE (*tp
) == SAVE_EXPR
&& data
== NULL
))
2790 /* Rewrite selected operations into unsigned arithmetics, so that they
2791 don't trap on overflow. */
2794 replace_trapping_overflow (tree
*tp
, int *walk_subtrees
, void *data
)
2796 if (find_trapping_overflow (tp
, walk_subtrees
, data
))
2798 tree type
= TREE_TYPE (*tp
);
2799 tree utype
= unsigned_type_for (type
);
2801 int len
= TREE_OPERAND_LENGTH (*tp
);
2802 for (int i
= 0; i
< len
; ++i
)
2803 walk_tree (&TREE_OPERAND (*tp
, i
), replace_trapping_overflow
,
2804 data
, (hash_set
<tree
> *) data
);
2806 if (TREE_CODE (*tp
) == ABS_EXPR
)
2808 TREE_SET_CODE (*tp
, ABSU_EXPR
);
2809 TREE_TYPE (*tp
) = utype
;
2810 *tp
= fold_convert (type
, *tp
);
2814 TREE_TYPE (*tp
) = utype
;
2815 len
= TREE_OPERAND_LENGTH (*tp
);
2816 for (int i
= 0; i
< len
; ++i
)
2817 TREE_OPERAND (*tp
, i
)
2818 = fold_convert (utype
, TREE_OPERAND (*tp
, i
));
2819 *tp
= fold_convert (type
, *tp
);
2825 /* If any subexpression of EXPR can trap due to -ftrapv, rewrite it
2826 using unsigned arithmetics to avoid traps in it. */
2829 rewrite_to_non_trapping_overflow (tree expr
)
2833 hash_set
<tree
> pset
;
2834 if (!walk_tree (&expr
, find_trapping_overflow
, &pset
, &pset
))
2836 expr
= unshare_expr (expr
);
2838 walk_tree (&expr
, replace_trapping_overflow
, &pset
, &pset
);
2842 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2843 an assignment or a conditional) may throw. */
2846 stmt_could_throw_1_p (gassign
*stmt
)
2848 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2849 bool honor_nans
= false;
2850 bool honor_snans
= false;
2851 bool fp_operation
= false;
2852 bool honor_trapv
= false;
2857 if (TREE_CODE_CLASS (code
) == tcc_comparison
2858 || TREE_CODE_CLASS (code
) == tcc_unary
2859 || TREE_CODE_CLASS (code
) == tcc_binary
)
2861 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2862 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2864 t
= gimple_expr_type (stmt
);
2865 fp_operation
= FLOAT_TYPE_P (t
);
2868 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2869 honor_snans
= flag_signaling_nans
!= 0;
2871 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2875 /* First check the LHS. */
2876 if (tree_could_trap_p (gimple_assign_lhs (stmt
)))
2879 /* Check if the main expression may trap. */
2880 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2881 honor_nans
, honor_snans
,
2882 gimple_assign_rhs2 (stmt
),
2887 /* If the expression does not trap, see if any of the individual operands may
2889 for (i
= 1; i
< gimple_num_ops (stmt
); i
++)
2890 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2897 /* Return true if statement STMT within FUN could throw an exception. */
2900 stmt_could_throw_p (function
*fun
, gimple
*stmt
)
2902 if (!flag_exceptions
)
2905 /* The only statements that can throw an exception are assignments,
2906 conditionals, calls, resx, and asms. */
2907 switch (gimple_code (stmt
))
2913 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2917 if (fun
&& !fun
->can_throw_non_call_exceptions
)
2919 gcond
*cond
= as_a
<gcond
*> (stmt
);
2920 tree lhs
= gimple_cond_lhs (cond
);
2921 return operation_could_trap_p (gimple_cond_code (cond
),
2922 FLOAT_TYPE_P (TREE_TYPE (lhs
)),
2927 if ((fun
&& !fun
->can_throw_non_call_exceptions
)
2928 || gimple_clobber_p (stmt
))
2930 return stmt_could_throw_1_p (as_a
<gassign
*> (stmt
));
2933 if (fun
&& !fun
->can_throw_non_call_exceptions
)
2935 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2943 /* Return true if expression T could throw an exception. */
2946 tree_could_throw_p (tree t
)
2948 if (!flag_exceptions
)
2950 if (TREE_CODE (t
) == MODIFY_EXPR
)
2952 if (cfun
->can_throw_non_call_exceptions
2953 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2955 t
= TREE_OPERAND (t
, 1);
2958 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2959 t
= TREE_OPERAND (t
, 0);
2960 if (TREE_CODE (t
) == CALL_EXPR
)
2961 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2962 if (cfun
->can_throw_non_call_exceptions
)
2963 return tree_could_trap_p (t
);
2967 /* Return true if STMT can throw an exception that is not caught within its
2968 function FUN. FUN can be NULL but the function is extra conservative
2972 stmt_can_throw_external (function
*fun
, gimple
*stmt
)
2976 if (!stmt_could_throw_p (fun
, stmt
))
2981 lp_nr
= lookup_stmt_eh_lp_fn (fun
, stmt
);
2985 /* Return true if STMT can throw an exception that is caught within its
2989 stmt_can_throw_internal (function
*fun
, gimple
*stmt
)
2993 gcc_checking_assert (fun
);
2994 if (!stmt_could_throw_p (fun
, stmt
))
2997 lp_nr
= lookup_stmt_eh_lp_fn (fun
, stmt
);
3001 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
3002 remove any entry it might have from the EH table. Return true if
3003 any change was made. */
3006 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple
*stmt
)
3008 if (stmt_could_throw_p (ifun
, stmt
))
3010 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
3013 /* Likewise, but always use the current function. */
3016 maybe_clean_eh_stmt (gimple
*stmt
)
3018 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
3021 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
3022 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
3023 in the table if it should be in there. Return TRUE if a replacement was
3024 done that my require an EH edge purge. */
3027 maybe_clean_or_replace_eh_stmt (gimple
*old_stmt
, gimple
*new_stmt
)
3029 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
3033 bool new_stmt_could_throw
= stmt_could_throw_p (cfun
, new_stmt
);
3035 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
3038 remove_stmt_from_eh_lp (old_stmt
);
3039 if (new_stmt_could_throw
)
3041 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
3051 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
3052 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
3053 operand is the return value of duplicate_eh_regions. */
3056 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple
*new_stmt
,
3057 struct function
*old_fun
, gimple
*old_stmt
,
3058 hash_map
<void *, void *> *map
,
3061 int old_lp_nr
, new_lp_nr
;
3063 if (!stmt_could_throw_p (new_fun
, new_stmt
))
3066 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
3069 if (default_lp_nr
== 0)
3071 new_lp_nr
= default_lp_nr
;
3073 else if (old_lp_nr
> 0)
3075 eh_landing_pad old_lp
, new_lp
;
3077 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
3078 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
3079 new_lp_nr
= new_lp
->index
;
3083 eh_region old_r
, new_r
;
3085 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
3086 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
3087 new_lp_nr
= -new_r
->index
;
3090 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
3094 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
3095 and thus no remapping is required. */
3098 maybe_duplicate_eh_stmt (gimple
*new_stmt
, gimple
*old_stmt
)
3102 if (!stmt_could_throw_p (cfun
, new_stmt
))
3105 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
3109 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
3113 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
3114 GIMPLE_TRY) that are similar enough to be considered the same. Currently
3115 this only handles handlers consisting of a single call, as that's the
3116 important case for C++: a destructor call for a particular object showing
3117 up in multiple handlers. */
3120 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
3122 gimple_stmt_iterator gsi
;
3123 gimple
*ones
, *twos
;
3126 gsi
= gsi_start (oneh
);
3127 if (!gsi_one_before_end_p (gsi
))
3129 ones
= gsi_stmt (gsi
);
3131 gsi
= gsi_start (twoh
);
3132 if (!gsi_one_before_end_p (gsi
))
3134 twos
= gsi_stmt (gsi
);
3136 if (!is_gimple_call (ones
)
3137 || !is_gimple_call (twos
)
3138 || gimple_call_lhs (ones
)
3139 || gimple_call_lhs (twos
)
3140 || gimple_call_chain (ones
)
3141 || gimple_call_chain (twos
)
3142 || !gimple_call_same_target_p (ones
, twos
)
3143 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3146 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3147 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3148 gimple_call_arg (twos
, ai
), 0))
3155 try { A() } finally { try { ~B() } catch { ~A() } }
3156 try { ... } finally { ~A() }
3158 try { A() } catch { ~B() }
3159 try { ~B() ... } finally { ~A() }
3161 This occurs frequently in C++, where A is a local variable and B is a
3162 temporary used in the initializer for A. */
3165 optimize_double_finally (gtry
*one
, gtry
*two
)
3168 gimple_stmt_iterator gsi
;
3171 cleanup
= gimple_try_cleanup (one
);
3172 gsi
= gsi_start (cleanup
);
3173 if (!gsi_one_before_end_p (gsi
))
3176 oneh
= gsi_stmt (gsi
);
3177 if (gimple_code (oneh
) != GIMPLE_TRY
3178 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3181 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3183 gimple_seq seq
= gimple_try_eval (oneh
);
3185 gimple_try_set_cleanup (one
, seq
);
3186 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3187 seq
= copy_gimple_seq_and_replace_locals (seq
);
3188 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3189 gimple_try_set_eval (two
, seq
);
3193 /* Perform EH refactoring optimizations that are simpler to do when code
3194 flow has been lowered but EH structures haven't. */
3197 refactor_eh_r (gimple_seq seq
)
3199 gimple_stmt_iterator gsi
;
3204 gsi
= gsi_start (seq
);
3208 if (gsi_end_p (gsi
))
3211 two
= gsi_stmt (gsi
);
3213 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3214 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3215 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3216 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3217 optimize_double_finally (try_one
, try_two
);
3219 switch (gimple_code (one
))
3222 refactor_eh_r (gimple_try_eval (one
));
3223 refactor_eh_r (gimple_try_cleanup (one
));
3226 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3228 case GIMPLE_EH_FILTER
:
3229 refactor_eh_r (gimple_eh_filter_failure (one
));
3231 case GIMPLE_EH_ELSE
:
3233 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3234 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3235 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3250 const pass_data pass_data_refactor_eh
=
3252 GIMPLE_PASS
, /* type */
3254 OPTGROUP_NONE
, /* optinfo_flags */
3255 TV_TREE_EH
, /* tv_id */
3256 PROP_gimple_lcf
, /* properties_required */
3257 0, /* properties_provided */
3258 0, /* properties_destroyed */
3259 0, /* todo_flags_start */
3260 0, /* todo_flags_finish */
3263 class pass_refactor_eh
: public gimple_opt_pass
3266 pass_refactor_eh (gcc::context
*ctxt
)
3267 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3270 /* opt_pass methods: */
3271 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3272 virtual unsigned int execute (function
*)
3274 refactor_eh_r (gimple_body (current_function_decl
));
3278 }; // class pass_refactor_eh
3283 make_pass_refactor_eh (gcc::context
*ctxt
)
3285 return new pass_refactor_eh (ctxt
);
3288 /* At the end of gimple optimization, we can lower RESX. */
3291 lower_resx (basic_block bb
, gresx
*stmt
,
3292 hash_map
<eh_region
, tree
> *mnt_map
)
3295 eh_region src_r
, dst_r
;
3296 gimple_stmt_iterator gsi
;
3301 lp_nr
= lookup_stmt_eh_lp (stmt
);
3303 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3307 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3308 gsi
= gsi_last_bb (bb
);
3312 /* We can wind up with no source region when pass_cleanup_eh shows
3313 that there are no entries into an eh region and deletes it, but
3314 then the block that contains the resx isn't removed. This can
3315 happen without optimization when the switch statement created by
3316 lower_try_finally_switch isn't simplified to remove the eh case.
3318 Resolve this by expanding the resx node to an abort. */
3320 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3321 x
= gimple_build_call (fn
, 0);
3322 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3324 while (EDGE_COUNT (bb
->succs
) > 0)
3325 remove_edge (EDGE_SUCC (bb
, 0));
3329 /* When we have a destination region, we resolve this by copying
3330 the excptr and filter values into place, and changing the edge
3331 to immediately after the landing pad. */
3339 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3340 the failure decl into a new block, if needed. */
3341 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3343 tree
*slot
= mnt_map
->get (dst_r
);
3346 gimple_stmt_iterator gsi2
;
3348 new_bb
= create_empty_bb (bb
);
3349 new_bb
->count
= bb
->count
;
3350 add_bb_to_loop (new_bb
, bb
->loop_father
);
3351 lab
= gimple_block_label (new_bb
);
3352 gsi2
= gsi_start_bb (new_bb
);
3354 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3355 x
= gimple_build_call (fn
, 0);
3356 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3357 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3359 mnt_map
->put (dst_r
, lab
);
3364 new_bb
= label_to_block (cfun
, lab
);
3367 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3368 e
= make_single_succ_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3373 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3375 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3376 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3377 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3378 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3380 /* Update the flags for the outgoing edge. */
3381 e
= single_succ_edge (bb
);
3382 gcc_assert (e
->flags
& EDGE_EH
);
3383 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3384 e
->probability
= profile_probability::always ();
3386 /* If there are no more EH users of the landing pad, delete it. */
3387 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3388 if (e
->flags
& EDGE_EH
)
3392 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3393 remove_eh_landing_pad (lp
);
3403 /* When we don't have a destination region, this exception escapes
3404 up the call chain. We resolve this by generating a call to the
3405 _Unwind_Resume library function. */
3407 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3408 with no arguments for C++. Check for that. */
3409 if (src_r
->use_cxa_end_cleanup
)
3411 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3412 x
= gimple_build_call (fn
, 0);
3413 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3417 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3418 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3419 x
= gimple_build_call (fn
, 1, src_nr
);
3420 var
= create_tmp_var (ptr_type_node
);
3421 var
= make_ssa_name (var
, x
);
3422 gimple_call_set_lhs (x
, var
);
3423 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3425 /* When exception handling is delegated to a caller function, we
3426 have to guarantee that shadow memory variables living on stack
3427 will be cleaner before control is given to a parent function. */
3428 if (sanitize_flags_p (SANITIZE_ADDRESS
))
3431 = builtin_decl_implicit (BUILT_IN_ASAN_HANDLE_NO_RETURN
);
3432 gimple
*g
= gimple_build_call (decl
, 0);
3433 gimple_set_location (g
, gimple_location (stmt
));
3434 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
3437 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3438 x
= gimple_build_call (fn
, 1, var
);
3439 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3442 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3445 gsi_remove (&gsi
, true);
3452 const pass_data pass_data_lower_resx
=
3454 GIMPLE_PASS
, /* type */
3456 OPTGROUP_NONE
, /* optinfo_flags */
3457 TV_TREE_EH
, /* tv_id */
3458 PROP_gimple_lcf
, /* properties_required */
3459 0, /* properties_provided */
3460 0, /* properties_destroyed */
3461 0, /* todo_flags_start */
3462 0, /* todo_flags_finish */
3465 class pass_lower_resx
: public gimple_opt_pass
3468 pass_lower_resx (gcc::context
*ctxt
)
3469 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3472 /* opt_pass methods: */
3473 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3474 virtual unsigned int execute (function
*);
3476 }; // class pass_lower_resx
3479 pass_lower_resx::execute (function
*fun
)
3482 bool dominance_invalidated
= false;
3483 bool any_rewritten
= false;
3485 hash_map
<eh_region
, tree
> mnt_map
;
3487 FOR_EACH_BB_FN (bb
, fun
)
3489 gimple
*last
= last_stmt (bb
);
3490 if (last
&& is_gimple_resx (last
))
3492 dominance_invalidated
|=
3493 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3494 any_rewritten
= true;
3498 if (dominance_invalidated
)
3500 free_dominance_info (CDI_DOMINATORS
);
3501 free_dominance_info (CDI_POST_DOMINATORS
);
3504 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3510 make_pass_lower_resx (gcc::context
*ctxt
)
3512 return new pass_lower_resx (ctxt
);
3515 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3519 optimize_clobbers (basic_block bb
)
3521 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3522 bool any_clobbers
= false;
3523 bool seen_stack_restore
= false;
3527 /* Only optimize anything if the bb contains at least one clobber,
3528 ends with resx (checked by caller), optionally contains some
3529 debug stmts or labels, or at most one __builtin_stack_restore
3530 call, and has an incoming EH edge. */
3531 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3533 gimple
*stmt
= gsi_stmt (gsi
);
3534 if (is_gimple_debug (stmt
))
3536 if (gimple_clobber_p (stmt
))
3538 any_clobbers
= true;
3541 if (!seen_stack_restore
3542 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3544 seen_stack_restore
= true;
3547 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3553 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3554 if (e
->flags
& EDGE_EH
)
3558 gsi
= gsi_last_bb (bb
);
3559 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3561 gimple
*stmt
= gsi_stmt (gsi
);
3562 if (!gimple_clobber_p (stmt
))
3564 unlink_stmt_vdef (stmt
);
3565 gsi_remove (&gsi
, true);
3566 release_defs (stmt
);
3570 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3571 internal throw to successor BB.
3572 SUNK, if not NULL, is an array of sequences indexed by basic-block
3573 index to sink to and to pick up sinking opportunities from.
3574 If FOUND_OPPORTUNITY is not NULL then do not perform the optimization
3575 but set *FOUND_OPPORTUNITY to true. */
3578 sink_clobbers (basic_block bb
,
3579 gimple_seq
*sunk
= NULL
, bool *found_opportunity
= NULL
)
3583 gimple_stmt_iterator gsi
, dgsi
;
3585 bool any_clobbers
= false;
3588 /* Only optimize if BB has a single EH successor and
3589 all predecessor edges are EH too. */
3590 if (!single_succ_p (bb
)
3591 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3594 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3596 if ((e
->flags
& EDGE_EH
) == 0)
3600 /* And BB contains only CLOBBER stmts before the final
3602 gsi
= gsi_last_bb (bb
);
3603 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3605 gimple
*stmt
= gsi_stmt (gsi
);
3606 if (is_gimple_debug (stmt
))
3608 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3610 if (!gimple_clobber_p (stmt
))
3612 any_clobbers
= true;
3614 if (!any_clobbers
&& (!sunk
|| gimple_seq_empty_p (sunk
[bb
->index
])))
3617 /* If this was a dry run, tell it we found clobbers to sink. */
3618 if (found_opportunity
)
3620 *found_opportunity
= true;
3624 edge succe
= single_succ_edge (bb
);
3625 succbb
= succe
->dest
;
3627 /* See if there is a virtual PHI node to take an updated virtual
3630 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3631 !gsi_end_p (gpi
); gsi_next (&gpi
))
3633 tree res
= gimple_phi_result (gpi
.phi ());
3634 if (virtual_operand_p (res
))
3641 gimple
*first_sunk
= NULL
;
3642 gimple
*last_sunk
= NULL
;
3643 if (sunk
&& !(succbb
->flags
& BB_VISITED
))
3644 dgsi
= gsi_start (sunk
[succbb
->index
]);
3646 dgsi
= gsi_after_labels (succbb
);
3647 gsi
= gsi_last_bb (bb
);
3648 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3650 gimple
*stmt
= gsi_stmt (gsi
);
3652 if (is_gimple_debug (stmt
))
3654 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3656 lhs
= gimple_assign_lhs (stmt
);
3657 /* Unfortunately we don't have dominance info updated at this
3658 point, so checking if
3659 dominated_by_p (CDI_DOMINATORS, succbb,
3660 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3661 would be too costly. Thus, avoid sinking any clobbers that
3662 refer to non-(D) SSA_NAMEs. */
3663 if (TREE_CODE (lhs
) == MEM_REF
3664 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3665 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3667 unlink_stmt_vdef (stmt
);
3668 gsi_remove (&gsi
, true);
3669 release_defs (stmt
);
3673 /* As we do not change stmt order when sinking across a
3674 forwarder edge we can keep virtual operands in place. */
3675 gsi_remove (&gsi
, false);
3676 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3681 if (sunk
&& !gimple_seq_empty_p (sunk
[bb
->index
]))
3684 first_sunk
= gsi_stmt (gsi_last (sunk
[bb
->index
]));
3685 last_sunk
= gsi_stmt (gsi_start (sunk
[bb
->index
]));
3686 gsi_insert_seq_before_without_update (&dgsi
,
3687 sunk
[bb
->index
], GSI_NEW_STMT
);
3688 sunk
[bb
->index
] = NULL
;
3692 /* Adjust virtual operands if we sunk across a virtual PHI. */
3695 imm_use_iterator iter
;
3696 use_operand_p use_p
;
3698 tree phi_def
= gimple_phi_result (vphi
);
3699 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, phi_def
)
3700 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3701 SET_USE (use_p
, gimple_vdef (first_sunk
));
3702 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (phi_def
))
3704 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (first_sunk
)) = 1;
3705 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (phi_def
) = 0;
3707 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
),
3708 gimple_vuse (last_sunk
));
3709 SET_USE (gimple_vuse_op (last_sunk
), phi_def
);
3711 /* If there isn't a single predecessor but no virtual PHI node
3712 arrange for virtual operands to be renamed. */
3713 else if (!single_pred_p (succbb
)
3714 && TREE_CODE (gimple_vuse (last_sunk
)) == SSA_NAME
)
3716 mark_virtual_operand_for_renaming (gimple_vuse (last_sunk
));
3717 todo
|= TODO_update_ssa_only_virtuals
;
3724 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3725 we have found some duplicate labels and removed some edges. */
3728 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3730 gimple_stmt_iterator gsi
;
3735 bool redirected
= false;
3737 region_nr
= gimple_eh_dispatch_region (stmt
);
3738 r
= get_eh_region_from_number (region_nr
);
3740 gsi
= gsi_last_bb (src
);
3746 auto_vec
<tree
> labels
;
3747 tree default_label
= NULL
;
3751 hash_set
<tree
> seen_values
;
3753 /* Collect the labels for a switch. Zero the post_landing_pad
3754 field becase we'll no longer have anything keeping these labels
3755 in existence and the optimizer will be free to merge these
3757 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3759 tree tp_node
, flt_node
, lab
= c
->label
;
3760 bool have_label
= false;
3763 tp_node
= c
->type_list
;
3764 flt_node
= c
->filter_list
;
3766 if (tp_node
== NULL
)
3768 default_label
= lab
;
3773 /* Filter out duplicate labels that arise when this handler
3774 is shadowed by an earlier one. When no labels are
3775 attached to the handler anymore, we remove
3776 the corresponding edge and then we delete unreachable
3777 blocks at the end of this pass. */
3778 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3780 tree t
= build_case_label (TREE_VALUE (flt_node
),
3782 labels
.safe_push (t
);
3783 seen_values
.add (TREE_VALUE (flt_node
));
3787 tp_node
= TREE_CHAIN (tp_node
);
3788 flt_node
= TREE_CHAIN (flt_node
);
3793 remove_edge (find_edge (src
, label_to_block (cfun
, lab
)));
3798 /* Clean up the edge flags. */
3799 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3801 if (e
->flags
& EDGE_FALLTHRU
)
3803 /* If there was no catch-all, use the fallthru edge. */
3804 if (default_label
== NULL
)
3805 default_label
= gimple_block_label (e
->dest
);
3806 e
->flags
&= ~EDGE_FALLTHRU
;
3809 gcc_assert (default_label
!= NULL
);
3811 /* Don't generate a switch if there's only a default case.
3812 This is common in the form of try { A; } catch (...) { B; }. */
3813 if (!labels
.exists ())
3815 e
= single_succ_edge (src
);
3816 e
->flags
|= EDGE_FALLTHRU
;
3820 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3821 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3823 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3824 filter
= make_ssa_name (filter
, x
);
3825 gimple_call_set_lhs (x
, filter
);
3826 gimple_set_location (x
, gimple_location (stmt
));
3827 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3829 /* Turn the default label into a default case. */
3830 default_label
= build_case_label (NULL
, NULL
, default_label
);
3831 sort_case_labels (labels
);
3833 x
= gimple_build_switch (filter
, default_label
, labels
);
3834 gimple_set_location (x
, gimple_location (stmt
));
3835 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3840 case ERT_ALLOWED_EXCEPTIONS
:
3842 edge b_e
= BRANCH_EDGE (src
);
3843 edge f_e
= FALLTHRU_EDGE (src
);
3845 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3846 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3848 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3849 filter
= make_ssa_name (filter
, x
);
3850 gimple_call_set_lhs (x
, filter
);
3851 gimple_set_location (x
, gimple_location (stmt
));
3852 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3854 r
->u
.allowed
.label
= NULL
;
3855 x
= gimple_build_cond (EQ_EXPR
, filter
,
3856 build_int_cst (TREE_TYPE (filter
),
3857 r
->u
.allowed
.filter
),
3858 NULL_TREE
, NULL_TREE
);
3859 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3861 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3862 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3870 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3871 gsi_remove (&gsi
, true);
3877 const pass_data pass_data_lower_eh_dispatch
=
3879 GIMPLE_PASS
, /* type */
3880 "ehdisp", /* name */
3881 OPTGROUP_NONE
, /* optinfo_flags */
3882 TV_TREE_EH
, /* tv_id */
3883 PROP_gimple_lcf
, /* properties_required */
3884 0, /* properties_provided */
3885 0, /* properties_destroyed */
3886 0, /* todo_flags_start */
3887 0, /* todo_flags_finish */
3890 class pass_lower_eh_dispatch
: public gimple_opt_pass
3893 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3894 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3897 /* opt_pass methods: */
3898 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3899 virtual unsigned int execute (function
*);
3901 }; // class pass_lower_eh_dispatch
3904 pass_lower_eh_dispatch::execute (function
*fun
)
3908 bool redirected
= false;
3909 bool any_resx_to_process
= false;
3911 assign_filter_values ();
3913 FOR_EACH_BB_FN (bb
, fun
)
3915 gimple
*last
= last_stmt (bb
);
3918 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3920 redirected
|= lower_eh_dispatch (bb
,
3921 as_a
<geh_dispatch
*> (last
));
3922 flags
|= TODO_update_ssa_only_virtuals
;
3924 else if (gimple_code (last
) == GIMPLE_RESX
)
3926 if (stmt_can_throw_external (fun
, last
))
3927 optimize_clobbers (bb
);
3928 else if (!any_resx_to_process
)
3929 sink_clobbers (bb
, NULL
, &any_resx_to_process
);
3931 bb
->flags
&= ~BB_VISITED
;
3935 free_dominance_info (CDI_DOMINATORS
);
3936 delete_unreachable_blocks ();
3939 if (any_resx_to_process
)
3941 /* Make sure to catch all secondary sinking opportunities by processing
3942 blocks in RPO order and after all CFG modifications from lowering
3943 and unreachable block removal. */
3944 int *rpo
= XNEWVEC (int, n_basic_blocks_for_fn (fun
));
3945 int rpo_n
= pre_and_rev_post_order_compute_fn (fun
, NULL
, rpo
, false);
3946 gimple_seq
*sunk
= XCNEWVEC (gimple_seq
, last_basic_block_for_fn (fun
));
3947 for (int i
= 0; i
< rpo_n
; ++i
)
3949 bb
= BASIC_BLOCK_FOR_FN (fun
, rpo
[i
]);
3950 gimple
*last
= last_stmt (bb
);
3952 && gimple_code (last
) == GIMPLE_RESX
3953 && !stmt_can_throw_external (fun
, last
))
3954 flags
|= sink_clobbers (bb
, sunk
);
3955 /* If there were any clobbers sunk into this BB, insert them now. */
3956 if (!gimple_seq_empty_p (sunk
[bb
->index
]))
3958 gimple_stmt_iterator gsi
= gsi_after_labels (bb
);
3959 gsi_insert_seq_before (&gsi
, sunk
[bb
->index
], GSI_NEW_STMT
);
3960 sunk
[bb
->index
] = NULL
;
3962 bb
->flags
|= BB_VISITED
;
3974 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3976 return new pass_lower_eh_dispatch (ctxt
);
3979 /* Walk statements, see what regions and, optionally, landing pads
3980 are really referenced.
3982 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3983 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3985 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3988 The caller is responsible for freeing the returned sbitmaps. */
3991 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3993 sbitmap r_reachable
, lp_reachable
;
3995 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3996 gcc_checking_assert (r_reachablep
!= NULL
);
3998 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3999 bitmap_clear (r_reachable
);
4000 *r_reachablep
= r_reachable
;
4002 if (mark_landing_pads
)
4004 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
4005 bitmap_clear (lp_reachable
);
4006 *lp_reachablep
= lp_reachable
;
4009 lp_reachable
= NULL
;
4011 FOR_EACH_BB_FN (bb
, cfun
)
4013 gimple_stmt_iterator gsi
;
4015 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4017 gimple
*stmt
= gsi_stmt (gsi
);
4019 if (mark_landing_pads
)
4021 int lp_nr
= lookup_stmt_eh_lp (stmt
);
4023 /* Negative LP numbers are MUST_NOT_THROW regions which
4024 are not considered BB enders. */
4026 bitmap_set_bit (r_reachable
, -lp_nr
);
4028 /* Positive LP numbers are real landing pads, and BB enders. */
4031 gcc_assert (gsi_one_before_end_p (gsi
));
4032 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
4033 bitmap_set_bit (r_reachable
, region
->index
);
4034 bitmap_set_bit (lp_reachable
, lp_nr
);
4038 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
4039 switch (gimple_code (stmt
))
4042 bitmap_set_bit (r_reachable
,
4043 gimple_resx_region (as_a
<gresx
*> (stmt
)));
4045 case GIMPLE_EH_DISPATCH
:
4046 bitmap_set_bit (r_reachable
,
4047 gimple_eh_dispatch_region (
4048 as_a
<geh_dispatch
*> (stmt
)));
4051 if (gimple_call_builtin_p (stmt
, BUILT_IN_EH_COPY_VALUES
))
4052 for (int i
= 0; i
< 2; ++i
)
4054 tree rt
= gimple_call_arg (stmt
, i
);
4055 HOST_WIDE_INT ri
= tree_to_shwi (rt
);
4057 gcc_assert (ri
== (int)ri
);
4058 bitmap_set_bit (r_reachable
, ri
);
4068 /* Remove unreachable handlers and unreachable landing pads. */
4071 remove_unreachable_handlers (void)
4073 sbitmap r_reachable
, lp_reachable
;
4078 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
4082 fprintf (dump_file
, "Before removal of unreachable regions:\n");
4083 dump_eh_tree (dump_file
, cfun
);
4084 fprintf (dump_file
, "Reachable regions: ");
4085 dump_bitmap_file (dump_file
, r_reachable
);
4086 fprintf (dump_file
, "Reachable landing pads: ");
4087 dump_bitmap_file (dump_file
, lp_reachable
);
4092 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
4093 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
4095 "Removing unreachable region %d\n",
4099 remove_unreachable_eh_regions (r_reachable
);
4101 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
4102 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
4106 "Removing unreachable landing pad %d\n",
4108 remove_eh_landing_pad (lp
);
4113 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
4114 dump_eh_tree (dump_file
, cfun
);
4115 fprintf (dump_file
, "\n\n");
4118 sbitmap_free (r_reachable
);
4119 sbitmap_free (lp_reachable
);
4122 verify_eh_tree (cfun
);
4125 /* Remove unreachable handlers if any landing pads have been removed after
4126 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
4129 maybe_remove_unreachable_handlers (void)
4134 if (cfun
->eh
== NULL
)
4137 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
4139 && (lp
->post_landing_pad
== NULL_TREE
4140 || label_to_block (cfun
, lp
->post_landing_pad
) == NULL
))
4142 remove_unreachable_handlers ();
4147 /* Remove regions that do not have landing pads. This assumes
4148 that remove_unreachable_handlers has already been run, and
4149 that we've just manipulated the landing pads since then.
4151 Preserve regions with landing pads and regions that prevent
4152 exceptions from propagating further, even if these regions
4153 are not reachable. */
4156 remove_unreachable_handlers_no_lp (void)
4159 sbitmap r_reachable
;
4162 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
4164 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
4169 if (region
->landing_pads
!= NULL
4170 || region
->type
== ERT_MUST_NOT_THROW
)
4171 bitmap_set_bit (r_reachable
, region
->index
);
4174 && !bitmap_bit_p (r_reachable
, region
->index
))
4176 "Removing unreachable region %d\n",
4180 remove_unreachable_eh_regions (r_reachable
);
4182 sbitmap_free (r_reachable
);
4185 /* Undo critical edge splitting on an EH landing pad. Earlier, we
4186 optimisticaly split all sorts of edges, including EH edges. The
4187 optimization passes in between may not have needed them; if not,
4188 we should undo the split.
4190 Recognize this case by having one EH edge incoming to the BB and
4191 one normal edge outgoing; BB should be empty apart from the
4192 post_landing_pad label.
4194 Note that this is slightly different from the empty handler case
4195 handled by cleanup_empty_eh, in that the actual handler may yet
4196 have actual code but the landing pad has been separated from the
4197 handler. As such, cleanup_empty_eh relies on this transformation
4198 having been done first. */
4201 unsplit_eh (eh_landing_pad lp
)
4203 basic_block bb
= label_to_block (cfun
, lp
->post_landing_pad
);
4204 gimple_stmt_iterator gsi
;
4207 /* Quickly check the edge counts on BB for singularity. */
4208 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4210 e_in
= single_pred_edge (bb
);
4211 e_out
= single_succ_edge (bb
);
4213 /* Input edge must be EH and output edge must be normal. */
4214 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4217 /* The block must be empty except for the labels and debug insns. */
4218 gsi
= gsi_after_labels (bb
);
4219 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4220 gsi_next_nondebug (&gsi
);
4221 if (!gsi_end_p (gsi
))
4224 /* The destination block must not already have a landing pad
4225 for a different region. */
4226 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4228 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4234 lab
= gimple_label_label (label_stmt
);
4235 lp_nr
= EH_LANDING_PAD_NR (lab
);
4236 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4240 /* The new destination block must not already be a destination of
4241 the source block, lest we merge fallthru and eh edges and get
4242 all sorts of confused. */
4243 if (find_edge (e_in
->src
, e_out
->dest
))
4246 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4247 thought this should have been cleaned up by a phicprop pass, but
4248 that doesn't appear to handle virtuals. Propagate by hand. */
4249 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4251 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4254 gphi
*phi
= gpi
.phi ();
4255 tree lhs
= gimple_phi_result (phi
);
4256 tree rhs
= gimple_phi_arg_def (phi
, 0);
4257 use_operand_p use_p
;
4258 imm_use_iterator iter
;
4260 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4262 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4263 SET_USE (use_p
, rhs
);
4266 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4267 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4269 remove_phi_node (&gpi
, true);
4273 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4274 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4275 lp
->index
, e_out
->dest
->index
);
4277 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4278 a successor edge, humor it. But do the real CFG change with the
4279 predecessor of E_OUT in order to preserve the ordering of arguments
4280 to the PHI nodes in E_OUT->DEST. */
4281 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4282 redirect_edge_pred (e_out
, e_in
->src
);
4283 e_out
->flags
= e_in
->flags
;
4284 e_out
->probability
= e_in
->probability
;
4290 /* Examine each landing pad block and see if it matches unsplit_eh. */
4293 unsplit_all_eh (void)
4295 bool changed
= false;
4299 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4301 changed
|= unsplit_eh (lp
);
4306 /* Wrapper around unsplit_all_eh that makes it usable everywhere. */
4309 unsplit_eh_edges (void)
4313 /* unsplit_all_eh can die looking up unreachable landing pads. */
4314 maybe_remove_unreachable_handlers ();
4316 changed
= unsplit_all_eh ();
4318 /* If EH edges have been unsplit, delete unreachable forwarder blocks. */
4321 free_dominance_info (CDI_DOMINATORS
);
4322 free_dominance_info (CDI_POST_DOMINATORS
);
4323 delete_unreachable_blocks ();
4327 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4328 to OLD_BB to NEW_BB; return true on success, false on failure.
4330 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4331 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4332 Virtual PHIs may be deleted and marked for renaming. */
4335 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4336 edge old_bb_out
, bool change_region
)
4338 gphi_iterator ngsi
, ogsi
;
4341 bitmap ophi_handled
;
4343 /* The destination block must not be a regular successor for any
4344 of the preds of the landing pad. Thus, avoid turning
4354 which CFG verification would choke on. See PR45172 and PR51089. */
4355 if (!single_pred_p (new_bb
))
4356 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4357 if (find_edge (e
->src
, new_bb
))
4360 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4361 redirect_edge_var_map_clear (e
);
4363 ophi_handled
= BITMAP_ALLOC (NULL
);
4365 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4366 for the edges we're going to move. */
4367 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4369 gphi
*ophi
, *nphi
= ngsi
.phi ();
4372 nresult
= gimple_phi_result (nphi
);
4373 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4375 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4376 the source ssa_name. */
4378 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4381 if (gimple_phi_result (ophi
) == nop
)
4386 /* If we did find the corresponding PHI, copy those inputs. */
4389 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4390 if (!has_single_use (nop
))
4392 imm_use_iterator imm_iter
;
4393 use_operand_p use_p
;
4395 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4397 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4398 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4399 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4403 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4404 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4409 if ((e
->flags
& EDGE_EH
) == 0)
4411 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4412 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4413 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4416 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4417 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4418 variable is unchanged from input to the block and we can simply
4419 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4423 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4424 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4425 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4429 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4430 we don't know what values from the other edges into NEW_BB to use. */
4431 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4433 gphi
*ophi
= ogsi
.phi ();
4434 tree oresult
= gimple_phi_result (ophi
);
4435 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4439 /* Finally, move the edges and update the PHIs. */
4440 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4441 if (e
->flags
& EDGE_EH
)
4443 /* ??? CFG manipluation routines do not try to update loop
4444 form on edge redirection. Do so manually here for now. */
4445 /* If we redirect a loop entry or latch edge that will either create
4446 a multiple entry loop or rotate the loop. If the loops merge
4447 we may have created a loop with multiple latches.
4448 All of this isn't easily fixed thus cancel the affected loop
4449 and mark the other loop as possibly having multiple latches. */
4450 if (e
->dest
== e
->dest
->loop_father
->header
)
4452 mark_loop_for_removal (e
->dest
->loop_father
);
4453 new_bb
->loop_father
->latch
= NULL
;
4454 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4456 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4457 redirect_edge_succ (e
, new_bb
);
4458 flush_pending_stmts (e
);
4463 BITMAP_FREE (ophi_handled
);
4467 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4468 redirect_edge_var_map_clear (e
);
4469 BITMAP_FREE (ophi_handled
);
4473 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4474 old region to NEW_REGION at BB. */
4477 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4478 eh_landing_pad lp
, eh_region new_region
)
4480 gimple_stmt_iterator gsi
;
4483 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4487 lp
->region
= new_region
;
4488 lp
->next_lp
= new_region
->landing_pads
;
4489 new_region
->landing_pads
= lp
;
4491 /* Delete the RESX that was matched within the empty handler block. */
4492 gsi
= gsi_last_bb (bb
);
4493 unlink_stmt_vdef (gsi_stmt (gsi
));
4494 gsi_remove (&gsi
, true);
4496 /* Clean up E_OUT for the fallthru. */
4497 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4498 e_out
->probability
= profile_probability::always ();
4501 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4502 unsplitting than unsplit_eh was prepared to handle, e.g. when
4503 multiple incoming edges and phis are involved. */
4506 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4508 gimple_stmt_iterator gsi
;
4511 /* We really ought not have totally lost everything following
4512 a landing pad label. Given that BB is empty, there had better
4514 gcc_assert (e_out
!= NULL
);
4516 /* The destination block must not already have a landing pad
4517 for a different region. */
4519 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4521 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4526 lab
= gimple_label_label (stmt
);
4527 lp_nr
= EH_LANDING_PAD_NR (lab
);
4528 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4532 /* Attempt to move the PHIs into the successor block. */
4533 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4535 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4537 "Unsplit EH landing pad %d to block %i "
4538 "(via cleanup_empty_eh).\n",
4539 lp
->index
, e_out
->dest
->index
);
4546 /* Return true if edge E_FIRST is part of an empty infinite loop
4547 or leads to such a loop through a series of single successor
4551 infinite_empty_loop_p (edge e_first
)
4553 bool inf_loop
= false;
4556 if (e_first
->dest
== e_first
->src
)
4559 e_first
->src
->aux
= (void *) 1;
4560 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4562 gimple_stmt_iterator gsi
;
4568 e
->dest
->aux
= (void *) 1;
4569 gsi
= gsi_after_labels (e
->dest
);
4570 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4571 gsi_next_nondebug (&gsi
);
4572 if (!gsi_end_p (gsi
))
4575 e_first
->src
->aux
= NULL
;
4576 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4577 e
->dest
->aux
= NULL
;
4582 /* Examine the block associated with LP to determine if it's an empty
4583 handler for its EH region. If so, attempt to redirect EH edges to
4584 an outer region. Return true the CFG was updated in any way. This
4585 is similar to jump forwarding, just across EH edges. */
4588 cleanup_empty_eh (eh_landing_pad lp
)
4590 basic_block bb
= label_to_block (cfun
, lp
->post_landing_pad
);
4591 gimple_stmt_iterator gsi
;
4593 eh_region new_region
;
4596 bool has_non_eh_pred
;
4600 /* There can be zero or one edges out of BB. This is the quickest test. */
4601 switch (EDGE_COUNT (bb
->succs
))
4607 e_out
= single_succ_edge (bb
);
4613 gsi
= gsi_last_nondebug_bb (bb
);
4614 resx
= gsi_stmt (gsi
);
4615 if (resx
&& is_gimple_resx (resx
))
4617 if (stmt_can_throw_external (cfun
, resx
))
4618 optimize_clobbers (bb
);
4619 else if (sink_clobbers (bb
))
4623 gsi
= gsi_after_labels (bb
);
4625 /* Make sure to skip debug statements. */
4626 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4627 gsi_next_nondebug (&gsi
);
4629 /* If the block is totally empty, look for more unsplitting cases. */
4630 if (gsi_end_p (gsi
))
4632 /* For the degenerate case of an infinite loop bail out.
4633 If bb has no successors and is totally empty, which can happen e.g.
4634 because of incorrect noreturn attribute, bail out too. */
4636 || infinite_empty_loop_p (e_out
))
4639 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4642 /* The block should consist only of a single RESX statement, modulo a
4643 preceding call to __builtin_stack_restore if there is no outgoing
4644 edge, since the call can be eliminated in this case. */
4645 resx
= gsi_stmt (gsi
);
4646 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4648 gsi_next_nondebug (&gsi
);
4649 resx
= gsi_stmt (gsi
);
4651 if (!is_gimple_resx (resx
))
4653 gcc_assert (gsi_one_nondebug_before_end_p (gsi
));
4655 /* Determine if there are non-EH edges, or resx edges into the handler. */
4656 has_non_eh_pred
= false;
4657 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4658 if (!(e
->flags
& EDGE_EH
))
4659 has_non_eh_pred
= true;
4661 /* Find the handler that's outer of the empty handler by looking at
4662 where the RESX instruction was vectored. */
4663 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4664 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4666 /* If there's no destination region within the current function,
4667 redirection is trivial via removing the throwing statements from
4668 the EH region, removing the EH edges, and allowing the block
4669 to go unreachable. */
4670 if (new_region
== NULL
)
4672 gcc_assert (e_out
== NULL
);
4673 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4674 if (e
->flags
& EDGE_EH
)
4676 gimple
*stmt
= last_stmt (e
->src
);
4677 remove_stmt_from_eh_lp (stmt
);
4685 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4686 to handle the abort and allow the blocks to go unreachable. */
4687 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4689 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4690 if (e
->flags
& EDGE_EH
)
4692 gimple
*stmt
= last_stmt (e
->src
);
4693 remove_stmt_from_eh_lp (stmt
);
4694 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4702 /* Try to redirect the EH edges and merge the PHIs into the destination
4703 landing pad block. If the merge succeeds, we'll already have redirected
4704 all the EH edges. The handler itself will go unreachable if there were
4706 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4709 /* Finally, if all input edges are EH edges, then we can (potentially)
4710 reduce the number of transfers from the runtime by moving the landing
4711 pad from the original region to the new region. This is a win when
4712 we remove the last CLEANUP region along a particular exception
4713 propagation path. Since nothing changes except for the region with
4714 which the landing pad is associated, the PHI nodes do not need to be
4716 if (!has_non_eh_pred
)
4718 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4719 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4720 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4721 lp
->index
, new_region
->index
);
4723 /* ??? The CFG didn't change, but we may have rendered the
4724 old EH region unreachable. Trigger a cleanup there. */
4731 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4732 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4733 remove_eh_landing_pad (lp
);
4737 /* Do a post-order traversal of the EH region tree. Examine each
4738 post_landing_pad block and see if we can eliminate it as empty. */
4741 cleanup_all_empty_eh (void)
4743 bool changed
= false;
4747 /* Ideally we'd walk the region tree and process LPs inner to outer
4748 to avoid quadraticness in EH redirection. Walking the LP array
4749 in reverse seems to be an approximation of that. */
4750 for (i
= vec_safe_length (cfun
->eh
->lp_array
) - 1; i
>= 1; --i
)
4752 lp
= (*cfun
->eh
->lp_array
)[i
];
4754 changed
|= cleanup_empty_eh (lp
);
4760 /* Perform cleanups and lowering of exception handling
4761 1) cleanups regions with handlers doing nothing are optimized out
4762 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4763 3) Info about regions that are containing instructions, and regions
4764 reachable via local EH edges is collected
4765 4) Eh tree is pruned for regions no longer necessary.
4767 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4768 Unify those that have the same failure decl and locus.
4772 execute_cleanup_eh_1 (void)
4774 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4775 looking up unreachable landing pads. */
4776 remove_unreachable_handlers ();
4778 /* Watch out for the region tree vanishing due to all unreachable. */
4779 if (cfun
->eh
->region_tree
)
4781 bool changed
= false;
4784 changed
|= unsplit_all_eh ();
4785 changed
|= cleanup_all_empty_eh ();
4789 free_dominance_info (CDI_DOMINATORS
);
4790 free_dominance_info (CDI_POST_DOMINATORS
);
4792 /* We delayed all basic block deletion, as we may have performed
4793 cleanups on EH edges while non-EH edges were still present. */
4794 delete_unreachable_blocks ();
4796 /* We manipulated the landing pads. Remove any region that no
4797 longer has a landing pad. */
4798 remove_unreachable_handlers_no_lp ();
4800 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4809 const pass_data pass_data_cleanup_eh
=
4811 GIMPLE_PASS
, /* type */
4812 "ehcleanup", /* name */
4813 OPTGROUP_NONE
, /* optinfo_flags */
4814 TV_TREE_EH
, /* tv_id */
4815 PROP_gimple_lcf
, /* properties_required */
4816 0, /* properties_provided */
4817 0, /* properties_destroyed */
4818 0, /* todo_flags_start */
4819 0, /* todo_flags_finish */
4822 class pass_cleanup_eh
: public gimple_opt_pass
4825 pass_cleanup_eh (gcc::context
*ctxt
)
4826 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4829 /* opt_pass methods: */
4830 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4831 virtual bool gate (function
*fun
)
4833 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4836 virtual unsigned int execute (function
*);
4838 }; // class pass_cleanup_eh
4841 pass_cleanup_eh::execute (function
*fun
)
4843 int ret
= execute_cleanup_eh_1 ();
4845 /* If the function no longer needs an EH personality routine
4846 clear it. This exposes cross-language inlining opportunities
4847 and avoids references to a never defined personality routine. */
4848 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4849 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4850 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4858 make_pass_cleanup_eh (gcc::context
*ctxt
)
4860 return new pass_cleanup_eh (ctxt
);
4863 /* Disable warnings about missing quoting in GCC diagnostics for
4864 the verification errors. Their format strings don't follow GCC
4865 diagnostic conventions but are only used for debugging. */
4867 # pragma GCC diagnostic push
4868 # pragma GCC diagnostic ignored "-Wformat-diag"
4871 /* Verify that BB containing STMT as the last statement, has precisely the
4872 edge that make_eh_edges would create. */
4875 verify_eh_edges (gimple
*stmt
)
4877 basic_block bb
= gimple_bb (stmt
);
4878 eh_landing_pad lp
= NULL
;
4883 lp_nr
= lookup_stmt_eh_lp (stmt
);
4885 lp
= get_eh_landing_pad_from_number (lp_nr
);
4888 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4890 if (e
->flags
& EDGE_EH
)
4894 error ("BB %i has multiple EH edges", bb
->index
);
4906 error ("BB %i cannot throw but has an EH edge", bb
->index
);
4912 if (!stmt_could_throw_p (cfun
, stmt
))
4914 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4918 if (eh_edge
== NULL
)
4920 error ("BB %i is missing an EH edge", bb
->index
);
4924 if (eh_edge
->dest
!= label_to_block (cfun
, lp
->post_landing_pad
))
4926 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4933 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4936 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4940 basic_block src
, dst
;
4941 bool want_fallthru
= true;
4945 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4946 src
= gimple_bb (stmt
);
4948 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4949 gcc_assert (e
->aux
== NULL
);
4954 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4956 dst
= label_to_block (cfun
, c
->label
);
4957 e
= find_edge (src
, dst
);
4960 error ("BB %i is missing an edge", src
->index
);
4965 /* A catch-all handler doesn't have a fallthru. */
4966 if (c
->type_list
== NULL
)
4968 want_fallthru
= false;
4974 case ERT_ALLOWED_EXCEPTIONS
:
4975 dst
= label_to_block (cfun
, r
->u
.allowed
.label
);
4976 e
= find_edge (src
, dst
);
4979 error ("BB %i is missing an edge", src
->index
);
4990 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4992 if (e
->flags
& EDGE_FALLTHRU
)
4994 if (fall_edge
!= NULL
)
4996 error ("BB %i too many fallthru edges", src
->index
);
5005 error ("BB %i has incorrect edge", src
->index
);
5009 if ((fall_edge
!= NULL
) ^ want_fallthru
)
5011 error ("BB %i has incorrect fallthru edge", src
->index
);
5019 # pragma GCC diagnostic pop