1 /* Exception handling semantics and decomposition for trees.
2 Copyright (C) 2003-2017 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"
48 /* In some instances a tree and a gimple need to be stored in a same table,
49 i.e. in hash tables. This is a structure to do this. */
50 typedef union {tree
*tp
; tree t
; gimple
*g
;} treemple
;
52 /* Misc functions used in this file. */
54 /* Remember and lookup EH landing pad data for arbitrary statements.
55 Really this means any statement that could_throw_p. We could
56 stuff this information into the stmt_ann data structure, but:
58 (1) We absolutely rely on this information being kept until
59 we get to rtl. Once we're done with lowering here, if we lose
60 the information there's no way to recover it!
62 (2) There are many more statements that *cannot* throw as
63 compared to those that can. We should be saving some amount
64 of space by only allocating memory for those that can throw. */
66 /* Add statement T in function IFUN to landing pad NUM. */
69 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple
*t
, int num
)
71 gcc_assert (num
!= 0);
73 if (!get_eh_throw_stmt_table (ifun
))
74 set_eh_throw_stmt_table (ifun
, hash_map
<gimple
*, int>::create_ggc (31));
76 gcc_assert (!get_eh_throw_stmt_table (ifun
)->put (t
, num
));
79 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
82 add_stmt_to_eh_lp (gimple
*t
, int num
)
84 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
87 /* Add statement T to the single EH landing pad in REGION. */
90 record_stmt_eh_region (eh_region region
, gimple
*t
)
94 if (region
->type
== ERT_MUST_NOT_THROW
)
95 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
98 eh_landing_pad lp
= region
->landing_pads
;
100 lp
= gen_eh_landing_pad (region
);
102 gcc_assert (lp
->next_lp
== NULL
);
103 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
108 /* Remove statement T in function IFUN from its EH landing pad. */
111 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple
*t
)
113 if (!get_eh_throw_stmt_table (ifun
))
116 if (!get_eh_throw_stmt_table (ifun
)->get (t
))
119 get_eh_throw_stmt_table (ifun
)->remove (t
);
124 /* Remove statement T in the current function (cfun) from its
128 remove_stmt_from_eh_lp (gimple
*t
)
130 return remove_stmt_from_eh_lp_fn (cfun
, t
);
133 /* Determine if statement T is inside an EH region in function IFUN.
134 Positive numbers indicate a landing pad index; negative numbers
135 indicate a MUST_NOT_THROW region index; zero indicates that the
136 statement is not recorded in the region table. */
139 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple
*t
)
141 if (ifun
->eh
->throw_stmt_table
== NULL
)
144 int *lp_nr
= ifun
->eh
->throw_stmt_table
->get (t
);
145 return lp_nr
? *lp_nr
: 0;
148 /* Likewise, but always use the current function. */
151 lookup_stmt_eh_lp (gimple
*t
)
153 /* We can get called from initialized data when -fnon-call-exceptions
154 is on; prevent crash. */
157 return lookup_stmt_eh_lp_fn (cfun
, t
);
160 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
161 nodes and LABEL_DECL nodes. We will use this during the second phase to
162 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
164 struct finally_tree_node
166 /* When storing a GIMPLE_TRY, we have to record a gimple. However
167 when deciding whether a GOTO to a certain LABEL_DECL (which is a
168 tree) leaves the TRY block, its necessary to record a tree in
169 this field. Thus a treemple is used. */
174 /* Hashtable helpers. */
176 struct finally_tree_hasher
: free_ptr_hash
<finally_tree_node
>
178 static inline hashval_t
hash (const finally_tree_node
*);
179 static inline bool equal (const finally_tree_node
*,
180 const finally_tree_node
*);
184 finally_tree_hasher::hash (const finally_tree_node
*v
)
186 return (intptr_t)v
->child
.t
>> 4;
190 finally_tree_hasher::equal (const finally_tree_node
*v
,
191 const finally_tree_node
*c
)
193 return v
->child
.t
== c
->child
.t
;
196 /* Note that this table is *not* marked GTY. It is short-lived. */
197 static hash_table
<finally_tree_hasher
> *finally_tree
;
200 record_in_finally_tree (treemple child
, gtry
*parent
)
202 struct finally_tree_node
*n
;
203 finally_tree_node
**slot
;
205 n
= XNEW (struct finally_tree_node
);
209 slot
= finally_tree
->find_slot (n
, INSERT
);
215 collect_finally_tree (gimple
*stmt
, gtry
*region
);
217 /* Go through the gimple sequence. Works with collect_finally_tree to
218 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
221 collect_finally_tree_1 (gimple_seq seq
, gtry
*region
)
223 gimple_stmt_iterator gsi
;
225 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
226 collect_finally_tree (gsi_stmt (gsi
), region
);
230 collect_finally_tree (gimple
*stmt
, gtry
*region
)
234 switch (gimple_code (stmt
))
237 temp
.t
= gimple_label_label (as_a
<glabel
*> (stmt
));
238 record_in_finally_tree (temp
, region
);
242 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
245 record_in_finally_tree (temp
, region
);
246 collect_finally_tree_1 (gimple_try_eval (stmt
),
247 as_a
<gtry
*> (stmt
));
248 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
250 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
252 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
253 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
258 collect_finally_tree_1 (gimple_catch_handler (
259 as_a
<gcatch
*> (stmt
)),
263 case GIMPLE_EH_FILTER
:
264 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
269 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
270 collect_finally_tree_1 (gimple_eh_else_n_body (eh_else_stmt
), region
);
271 collect_finally_tree_1 (gimple_eh_else_e_body (eh_else_stmt
), region
);
276 /* A type, a decl, or some kind of statement that we're not
277 interested in. Don't walk them. */
283 /* Use the finally tree to determine if a jump from START to TARGET
284 would leave the try_finally node that START lives in. */
287 outside_finally_tree (treemple start
, gimple
*target
)
289 struct finally_tree_node n
, *p
;
294 p
= finally_tree
->find (&n
);
299 while (start
.g
!= target
);
304 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
305 nodes into a set of gotos, magic labels, and eh regions.
306 The eh region creation is straight-forward, but frobbing all the gotos
307 and such into shape isn't. */
309 /* The sequence into which we record all EH stuff. This will be
310 placed at the end of the function when we're all done. */
311 static gimple_seq eh_seq
;
313 /* Record whether an EH region contains something that can throw,
314 indexed by EH region number. */
315 static bitmap eh_region_may_contain_throw_map
;
317 /* The GOTO_QUEUE is an array of GIMPLE_GOTO and GIMPLE_RETURN
318 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
319 The idea is to record a gimple statement for everything except for
320 the conditionals, which get their labels recorded. Since labels are
321 of type 'tree', we need this node to store both gimple and tree
322 objects. REPL_STMT is the sequence used to replace the goto/return
323 statement. CONT_STMT is used to store the statement that allows
324 the return/goto to jump to the original destination. */
326 struct goto_queue_node
330 gimple_seq repl_stmt
;
333 /* This is used when index >= 0 to indicate that stmt is a label (as
334 opposed to a goto stmt). */
338 /* State of the world while lowering. */
342 /* What's "current" while constructing the eh region tree. These
343 correspond to variables of the same name in cfun->eh, which we
344 don't have easy access to. */
345 eh_region cur_region
;
347 /* What's "current" for the purposes of __builtin_eh_pointer. For
348 a CATCH, this is the associated TRY. For an EH_FILTER, this is
349 the associated ALLOWED_EXCEPTIONS, etc. */
350 eh_region ehp_region
;
352 /* Processing of TRY_FINALLY requires a bit more state. This is
353 split out into a separate structure so that we don't have to
354 copy so much when processing other nodes. */
355 struct leh_tf_state
*tf
;
360 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
361 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
362 this so that outside_finally_tree can reliably reference the tree used
363 in the collect_finally_tree data structures. */
364 gtry
*try_finally_expr
;
367 /* While lowering a top_p usually it is expanded into multiple statements,
368 thus we need the following field to store them. */
369 gimple_seq top_p_seq
;
371 /* The state outside this try_finally node. */
372 struct leh_state
*outer
;
374 /* The exception region created for it. */
377 /* The goto queue. */
378 struct goto_queue_node
*goto_queue
;
379 size_t goto_queue_size
;
380 size_t goto_queue_active
;
382 /* Pointer map to help in searching goto_queue when it is large. */
383 hash_map
<gimple
*, goto_queue_node
*> *goto_queue_map
;
385 /* The set of unique labels seen as entries in the goto queue. */
386 vec
<tree
> dest_array
;
388 /* A label to be added at the end of the completed transformed
389 sequence. It will be set if may_fallthru was true *at one time*,
390 though subsequent transformations may have cleared that flag. */
393 /* True if it is possible to fall out the bottom of the try block.
394 Cleared if the fallthru is converted to a goto. */
397 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
400 /* True if the finally block can receive an exception edge.
401 Cleared if the exception case is handled by code duplication. */
405 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gtry
*);
407 /* Search for STMT in the goto queue. Return the replacement,
408 or null if the statement isn't in the queue. */
410 #define LARGE_GOTO_QUEUE 20
412 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
415 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
419 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
421 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
422 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
423 return tf
->goto_queue
[i
].repl_stmt
;
427 /* If we have a large number of entries in the goto_queue, create a
428 pointer map and use that for searching. */
430 if (!tf
->goto_queue_map
)
432 tf
->goto_queue_map
= new hash_map
<gimple
*, goto_queue_node
*>;
433 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
435 bool existed
= tf
->goto_queue_map
->put (tf
->goto_queue
[i
].stmt
.g
,
437 gcc_assert (!existed
);
441 goto_queue_node
**slot
= tf
->goto_queue_map
->get (stmt
.g
);
443 return ((*slot
)->repl_stmt
);
448 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
449 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
450 then we can just splat it in, otherwise we add the new stmts immediately
451 after the GIMPLE_COND and redirect. */
454 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
455 gimple_stmt_iterator
*gsi
)
460 location_t loc
= gimple_location (gsi_stmt (*gsi
));
463 new_seq
= find_goto_replacement (tf
, temp
);
467 if (gimple_seq_singleton_p (new_seq
)
468 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
470 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
474 label
= create_artificial_label (loc
);
475 /* Set the new label for the GIMPLE_COND */
478 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
479 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
482 /* The real work of replace_goto_queue. Returns with TSI updated to
483 point to the next statement. */
485 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
488 replace_goto_queue_1 (gimple
*stmt
, struct leh_tf_state
*tf
,
489 gimple_stmt_iterator
*gsi
)
495 switch (gimple_code (stmt
))
500 seq
= find_goto_replacement (tf
, temp
);
503 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
504 gsi_remove (gsi
, false);
510 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
511 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
515 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
516 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
519 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (
520 as_a
<gcatch
*> (stmt
)),
523 case GIMPLE_EH_FILTER
:
524 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
528 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
529 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (eh_else_stmt
),
531 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (eh_else_stmt
),
537 /* These won't have gotos in them. */
544 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
547 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
549 gimple_stmt_iterator gsi
= gsi_start (*seq
);
551 while (!gsi_end_p (gsi
))
552 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
555 /* Replace all goto queue members. */
558 replace_goto_queue (struct leh_tf_state
*tf
)
560 if (tf
->goto_queue_active
== 0)
562 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
563 replace_goto_queue_stmt_list (&eh_seq
, tf
);
566 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
567 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
571 record_in_goto_queue (struct leh_tf_state
*tf
,
578 struct goto_queue_node
*q
;
580 gcc_assert (!tf
->goto_queue_map
);
582 active
= tf
->goto_queue_active
;
583 size
= tf
->goto_queue_size
;
586 size
= (size
? size
* 2 : 32);
587 tf
->goto_queue_size
= size
;
589 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
592 q
= &tf
->goto_queue
[active
];
593 tf
->goto_queue_active
= active
+ 1;
595 memset (q
, 0, sizeof (*q
));
598 q
->location
= location
;
599 q
->is_label
= is_label
;
602 /* Record the LABEL label in the goto queue contained in TF.
606 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
610 treemple temp
, new_stmt
;
615 /* Computed and non-local gotos do not get processed. Given
616 their nature we can neither tell whether we've escaped the
617 finally block nor redirect them if we knew. */
618 if (TREE_CODE (label
) != LABEL_DECL
)
621 /* No need to record gotos that don't leave the try block. */
623 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
626 if (! tf
->dest_array
.exists ())
628 tf
->dest_array
.create (10);
629 tf
->dest_array
.quick_push (label
);
634 int n
= tf
->dest_array
.length ();
635 for (index
= 0; index
< n
; ++index
)
636 if (tf
->dest_array
[index
] == label
)
639 tf
->dest_array
.safe_push (label
);
642 /* In the case of a GOTO we want to record the destination label,
643 since with a GIMPLE_COND we have an easy access to the then/else
646 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
649 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
650 node, and if so record that fact in the goto queue associated with that
654 maybe_record_in_goto_queue (struct leh_state
*state
, gimple
*stmt
)
656 struct leh_tf_state
*tf
= state
->tf
;
662 switch (gimple_code (stmt
))
666 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
667 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 2);
668 record_in_goto_queue_label (tf
, new_stmt
,
669 gimple_cond_true_label (cond_stmt
),
670 EXPR_LOCATION (*new_stmt
.tp
));
671 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 3);
672 record_in_goto_queue_label (tf
, new_stmt
,
673 gimple_cond_false_label (cond_stmt
),
674 EXPR_LOCATION (*new_stmt
.tp
));
679 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
680 gimple_location (stmt
));
684 tf
->may_return
= true;
686 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
696 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
697 was in fact structured, and we've not yet done jump threading, then none
698 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
701 verify_norecord_switch_expr (struct leh_state
*state
,
702 gswitch
*switch_expr
)
704 struct leh_tf_state
*tf
= state
->tf
;
710 n
= gimple_switch_num_labels (switch_expr
);
712 for (i
= 0; i
< n
; ++i
)
715 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
717 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
721 #define verify_norecord_switch_expr(state, switch_expr)
724 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
725 non-null, insert it before the new branch. */
728 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
732 /* In the case of a return, the queue node must be a gimple statement. */
733 gcc_assert (!q
->is_label
);
735 /* Note that the return value may have already been computed, e.g.,
748 should return 0, not 1. We don't have to do anything to make
749 this happens because the return value has been placed in the
750 RESULT_DECL already. */
752 q
->cont_stmt
= q
->stmt
.g
;
755 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
757 x
= gimple_build_goto (finlab
);
758 gimple_set_location (x
, q
->location
);
759 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
762 /* Similar, but easier, for GIMPLE_GOTO. */
765 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
766 struct leh_tf_state
*tf
)
770 gcc_assert (q
->is_label
);
772 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
775 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
777 x
= gimple_build_goto (finlab
);
778 gimple_set_location (x
, q
->location
);
779 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
782 /* Emit a standard landing pad sequence into SEQ for REGION. */
785 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
787 eh_landing_pad lp
= region
->landing_pads
;
791 lp
= gen_eh_landing_pad (region
);
793 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
794 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
796 x
= gimple_build_label (lp
->post_landing_pad
);
797 gimple_seq_add_stmt (seq
, x
);
800 /* Emit a RESX statement into SEQ for REGION. */
803 emit_resx (gimple_seq
*seq
, eh_region region
)
805 gresx
*x
= gimple_build_resx (region
->index
);
806 gimple_seq_add_stmt (seq
, x
);
808 record_stmt_eh_region (region
->outer
, x
);
811 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
814 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
816 geh_dispatch
*x
= gimple_build_eh_dispatch (region
->index
);
817 gimple_seq_add_stmt (seq
, x
);
820 /* Note that the current EH region may contain a throw, or a
821 call to a function which itself may contain a throw. */
824 note_eh_region_may_contain_throw (eh_region region
)
826 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
828 if (region
->type
== ERT_MUST_NOT_THROW
)
830 region
= region
->outer
;
836 /* Check if REGION has been marked as containing a throw. If REGION is
837 NULL, this predicate is false. */
840 eh_region_may_contain_throw (eh_region r
)
842 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
845 /* We want to transform
846 try { body; } catch { stuff; }
856 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
857 should be placed before the second operand, or NULL. OVER is
858 an existing label that should be put at the exit, or NULL. */
861 frob_into_branch_around (gtry
*tp
, eh_region region
, tree over
)
864 gimple_seq cleanup
, result
;
865 location_t loc
= gimple_location (tp
);
867 cleanup
= gimple_try_cleanup (tp
);
868 result
= gimple_try_eval (tp
);
871 emit_post_landing_pad (&eh_seq
, region
);
873 if (gimple_seq_may_fallthru (cleanup
))
876 over
= create_artificial_label (loc
);
877 x
= gimple_build_goto (over
);
878 gimple_set_location (x
, loc
);
879 gimple_seq_add_stmt (&cleanup
, x
);
881 gimple_seq_add_seq (&eh_seq
, cleanup
);
885 x
= gimple_build_label (over
);
886 gimple_seq_add_stmt (&result
, x
);
891 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
892 Make sure to record all new labels found. */
895 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
900 gimple_stmt_iterator gsi
;
902 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
904 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
906 gimple
*stmt
= gsi_stmt (gsi
);
907 /* We duplicate __builtin_stack_restore at -O0 in the hope of eliminating
908 it on the EH paths. When it is not eliminated, make it transparent in
910 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
911 gimple_set_location (stmt
, UNKNOWN_LOCATION
);
912 else if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
914 tree block
= gimple_block (stmt
);
915 gimple_set_location (stmt
, loc
);
916 gimple_set_block (stmt
, block
);
921 region
= outer_state
->tf
->try_finally_expr
;
922 collect_finally_tree_1 (new_seq
, region
);
927 /* A subroutine of lower_try_finally. Create a fallthru label for
928 the given try_finally state. The only tricky bit here is that
929 we have to make sure to record the label in our outer context. */
932 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
934 tree label
= tf
->fallthru_label
;
939 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
940 tf
->fallthru_label
= label
;
944 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
950 /* A subroutine of lower_try_finally. If FINALLY consits of a
951 GIMPLE_EH_ELSE node, return it. */
953 static inline geh_else
*
954 get_eh_else (gimple_seq finally
)
956 gimple
*x
= gimple_seq_first_stmt (finally
);
957 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
959 gcc_assert (gimple_seq_singleton_p (finally
));
960 return as_a
<geh_else
*> (x
);
965 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
966 langhook returns non-null, then the language requires that the exception
967 path out of a try_finally be treated specially. To wit: the code within
968 the finally block may not itself throw an exception. We have two choices
969 here. First we can duplicate the finally block and wrap it in a
970 must_not_throw region. Second, we can generate code like
975 if (fintmp == eh_edge)
976 protect_cleanup_actions;
979 where "fintmp" is the temporary used in the switch statement generation
980 alternative considered below. For the nonce, we always choose the first
983 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
986 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
987 struct leh_state
*this_state
,
988 struct leh_tf_state
*tf
)
990 gimple_seq finally
= gimple_try_cleanup (tf
->top_p
);
992 /* EH_ELSE doesn't come from user code; only compiler generated stuff.
993 It does need to be handled here, so as to separate the (different)
994 EH path from the normal path. But we should not attempt to wrap
995 it with a must-not-throw node (which indeed gets in the way). */
996 if (geh_else
*eh_else
= get_eh_else (finally
))
998 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
999 finally
= gimple_eh_else_e_body (eh_else
);
1001 /* Let the ELSE see the exception that's being processed. */
1002 eh_region save_ehp
= this_state
->ehp_region
;
1003 this_state
->ehp_region
= this_state
->cur_region
;
1004 lower_eh_constructs_1 (this_state
, &finally
);
1005 this_state
->ehp_region
= save_ehp
;
1009 /* First check for nothing to do. */
1010 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1012 tree actions
= lang_hooks
.eh_protect_cleanup_actions ();
1013 if (actions
== NULL
)
1017 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1018 gimple_location (tf
->try_finally_expr
));
1020 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1021 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1022 to be in an enclosing scope, but needs to be implemented at this level
1023 to avoid a nesting violation (see wrap_temporary_cleanups in
1024 cp/decl.c). Since it's logically at an outer level, we should call
1025 terminate before we get to it, so strip it away before adding the
1026 MUST_NOT_THROW filter. */
1027 gimple_stmt_iterator gsi
= gsi_start (finally
);
1028 gimple
*x
= gsi_stmt (gsi
);
1029 if (gimple_code (x
) == GIMPLE_TRY
1030 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1031 && gimple_try_catch_is_cleanup (x
))
1033 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1034 gsi_remove (&gsi
, false);
1037 /* Wrap the block with protect_cleanup_actions as the action. */
1038 geh_mnt
*eh_mnt
= gimple_build_eh_must_not_throw (actions
);
1039 gtry
*try_stmt
= gimple_build_try (finally
,
1040 gimple_seq_alloc_with_stmt (eh_mnt
),
1042 finally
= lower_eh_must_not_throw (outer_state
, try_stmt
);
1045 /* Drop all of this into the exception sequence. */
1046 emit_post_landing_pad (&eh_seq
, tf
->region
);
1047 gimple_seq_add_seq (&eh_seq
, finally
);
1048 if (gimple_seq_may_fallthru (finally
))
1049 emit_resx (&eh_seq
, tf
->region
);
1051 /* Having now been handled, EH isn't to be considered with
1052 the rest of the outgoing edges. */
1053 tf
->may_throw
= false;
1056 /* A subroutine of lower_try_finally. We have determined that there is
1057 no fallthru edge out of the finally block. This means that there is
1058 no outgoing edge corresponding to any incoming edge. Restructure the
1059 try_finally node for this special case. */
1062 lower_try_finally_nofallthru (struct leh_state
*state
,
1063 struct leh_tf_state
*tf
)
1069 struct goto_queue_node
*q
, *qe
;
1071 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1073 /* We expect that tf->top_p is a GIMPLE_TRY. */
1074 finally
= gimple_try_cleanup (tf
->top_p
);
1075 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1077 x
= gimple_build_label (lab
);
1078 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1081 qe
= q
+ tf
->goto_queue_active
;
1084 do_return_redirection (q
, lab
, NULL
);
1086 do_goto_redirection (q
, lab
, NULL
, tf
);
1088 replace_goto_queue (tf
);
1090 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1091 eh_else
= get_eh_else (finally
);
1094 finally
= gimple_eh_else_n_body (eh_else
);
1095 lower_eh_constructs_1 (state
, &finally
);
1096 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1100 finally
= gimple_eh_else_e_body (eh_else
);
1101 lower_eh_constructs_1 (state
, &finally
);
1103 emit_post_landing_pad (&eh_seq
, tf
->region
);
1104 gimple_seq_add_seq (&eh_seq
, finally
);
1109 lower_eh_constructs_1 (state
, &finally
);
1110 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1114 emit_post_landing_pad (&eh_seq
, tf
->region
);
1116 x
= gimple_build_goto (lab
);
1117 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1118 gimple_seq_add_stmt (&eh_seq
, x
);
1123 /* A subroutine of lower_try_finally. We have determined that there is
1124 exactly one destination of the finally block. Restructure the
1125 try_finally node for this special case. */
1128 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1130 struct goto_queue_node
*q
, *qe
;
1135 gimple_stmt_iterator gsi
;
1137 location_t loc
= gimple_location (tf
->try_finally_expr
);
1139 finally
= gimple_try_cleanup (tf
->top_p
);
1140 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1142 /* Since there's only one destination, and the destination edge can only
1143 either be EH or non-EH, that implies that all of our incoming edges
1144 are of the same type. Therefore we can lower EH_ELSE immediately. */
1145 eh_else
= get_eh_else (finally
);
1149 finally
= gimple_eh_else_e_body (eh_else
);
1151 finally
= gimple_eh_else_n_body (eh_else
);
1154 lower_eh_constructs_1 (state
, &finally
);
1156 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1158 gimple
*stmt
= gsi_stmt (gsi
);
1159 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1161 tree block
= gimple_block (stmt
);
1162 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1163 gimple_set_block (stmt
, block
);
1169 /* Only reachable via the exception edge. Add the given label to
1170 the head of the FINALLY block. Append a RESX at the end. */
1171 emit_post_landing_pad (&eh_seq
, tf
->region
);
1172 gimple_seq_add_seq (&eh_seq
, finally
);
1173 emit_resx (&eh_seq
, tf
->region
);
1177 if (tf
->may_fallthru
)
1179 /* Only reachable via the fallthru edge. Do nothing but let
1180 the two blocks run together; we'll fall out the bottom. */
1181 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1185 finally_label
= create_artificial_label (loc
);
1186 label_stmt
= gimple_build_label (finally_label
);
1187 gimple_seq_add_stmt (&tf
->top_p_seq
, label_stmt
);
1189 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1192 qe
= q
+ tf
->goto_queue_active
;
1196 /* Reachable by return expressions only. Redirect them. */
1198 do_return_redirection (q
, finally_label
, NULL
);
1199 replace_goto_queue (tf
);
1203 /* Reachable by goto expressions only. Redirect them. */
1205 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1206 replace_goto_queue (tf
);
1208 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1210 /* Reachable by goto to fallthru label only. Redirect it
1211 to the new label (already created, sadly), and do not
1212 emit the final branch out, or the fallthru label. */
1213 tf
->fallthru_label
= NULL
;
1218 /* Place the original return/goto to the original destination
1219 immediately after the finally block. */
1220 x
= tf
->goto_queue
[0].cont_stmt
;
1221 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1222 maybe_record_in_goto_queue (state
, x
);
1225 /* A subroutine of lower_try_finally. There are multiple edges incoming
1226 and outgoing from the finally block. Implement this by duplicating the
1227 finally block for every destination. */
1230 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1233 gimple_seq new_stmt
;
1238 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1240 finally
= gimple_try_cleanup (tf
->top_p
);
1242 /* Notice EH_ELSE, and simplify some of the remaining code
1243 by considering FINALLY to be the normal return path only. */
1244 eh_else
= get_eh_else (finally
);
1246 finally
= gimple_eh_else_n_body (eh_else
);
1248 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1251 if (tf
->may_fallthru
)
1253 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1254 lower_eh_constructs_1 (state
, &seq
);
1255 gimple_seq_add_seq (&new_stmt
, seq
);
1257 tmp
= lower_try_finally_fallthru_label (tf
);
1258 x
= gimple_build_goto (tmp
);
1259 gimple_set_location (x
, tf_loc
);
1260 gimple_seq_add_stmt (&new_stmt
, x
);
1265 /* We don't need to copy the EH path of EH_ELSE,
1266 since it is only emitted once. */
1268 seq
= gimple_eh_else_e_body (eh_else
);
1270 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1271 lower_eh_constructs_1 (state
, &seq
);
1273 emit_post_landing_pad (&eh_seq
, tf
->region
);
1274 gimple_seq_add_seq (&eh_seq
, seq
);
1275 emit_resx (&eh_seq
, tf
->region
);
1280 struct goto_queue_node
*q
, *qe
;
1281 int return_index
, index
;
1284 struct goto_queue_node
*q
;
1288 return_index
= tf
->dest_array
.length ();
1289 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1292 qe
= q
+ tf
->goto_queue_active
;
1295 index
= q
->index
< 0 ? return_index
: q
->index
;
1297 if (!labels
[index
].q
)
1298 labels
[index
].q
= q
;
1301 for (index
= 0; index
< return_index
+ 1; index
++)
1305 q
= labels
[index
].q
;
1309 lab
= labels
[index
].label
1310 = create_artificial_label (tf_loc
);
1312 if (index
== return_index
)
1313 do_return_redirection (q
, lab
, NULL
);
1315 do_goto_redirection (q
, lab
, NULL
, tf
);
1317 x
= gimple_build_label (lab
);
1318 gimple_seq_add_stmt (&new_stmt
, x
);
1320 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1321 lower_eh_constructs_1 (state
, &seq
);
1322 gimple_seq_add_seq (&new_stmt
, seq
);
1324 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1325 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1328 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1332 index
= q
->index
< 0 ? return_index
: q
->index
;
1334 if (labels
[index
].q
== q
)
1337 lab
= labels
[index
].label
;
1339 if (index
== return_index
)
1340 do_return_redirection (q
, lab
, NULL
);
1342 do_goto_redirection (q
, lab
, NULL
, tf
);
1345 replace_goto_queue (tf
);
1349 /* Need to link new stmts after running replace_goto_queue due
1350 to not wanting to process the same goto stmts twice. */
1351 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1354 /* A subroutine of lower_try_finally. There are multiple edges incoming
1355 and outgoing from the finally block. Implement this by instrumenting
1356 each incoming edge and creating a switch statement at the end of the
1357 finally block that branches to the appropriate destination. */
1360 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1362 struct goto_queue_node
*q
, *qe
;
1363 tree finally_tmp
, finally_label
;
1364 int return_index
, eh_index
, fallthru_index
;
1365 int nlabels
, ndests
, j
, last_case_index
;
1367 auto_vec
<tree
> case_label_vec
;
1368 gimple_seq switch_body
= NULL
;
1372 gimple
*switch_stmt
;
1374 hash_map
<tree
, gimple
*> *cont_map
= NULL
;
1375 /* The location of the TRY_FINALLY stmt. */
1376 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1377 /* The location of the finally block. */
1378 location_t finally_loc
;
1380 finally
= gimple_try_cleanup (tf
->top_p
);
1381 eh_else
= get_eh_else (finally
);
1383 /* Mash the TRY block to the head of the chain. */
1384 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1386 /* The location of the finally is either the last stmt in the finally
1387 block or the location of the TRY_FINALLY itself. */
1388 x
= gimple_seq_last_stmt (finally
);
1389 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1391 /* Prepare for switch statement generation. */
1392 nlabels
= tf
->dest_array
.length ();
1393 return_index
= nlabels
;
1394 eh_index
= return_index
+ tf
->may_return
;
1395 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1396 ndests
= fallthru_index
+ tf
->may_fallthru
;
1398 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1399 finally_label
= create_artificial_label (finally_loc
);
1401 /* We use vec::quick_push on case_label_vec throughout this function,
1402 since we know the size in advance and allocate precisely as muce
1404 case_label_vec
.create (ndests
);
1406 last_case_index
= 0;
1408 /* Begin inserting code for getting to the finally block. Things
1409 are done in this order to correspond to the sequence the code is
1412 if (tf
->may_fallthru
)
1414 x
= gimple_build_assign (finally_tmp
,
1415 build_int_cst (integer_type_node
,
1417 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1419 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1420 last_case
= build_case_label (tmp
, NULL
,
1421 create_artificial_label (tf_loc
));
1422 case_label_vec
.quick_push (last_case
);
1425 x
= gimple_build_label (CASE_LABEL (last_case
));
1426 gimple_seq_add_stmt (&switch_body
, x
);
1428 tmp
= lower_try_finally_fallthru_label (tf
);
1429 x
= gimple_build_goto (tmp
);
1430 gimple_set_location (x
, tf_loc
);
1431 gimple_seq_add_stmt (&switch_body
, x
);
1434 /* For EH_ELSE, emit the exception path (plus resx) now, then
1435 subsequently we only need consider the normal path. */
1440 finally
= gimple_eh_else_e_body (eh_else
);
1441 lower_eh_constructs_1 (state
, &finally
);
1443 emit_post_landing_pad (&eh_seq
, tf
->region
);
1444 gimple_seq_add_seq (&eh_seq
, finally
);
1445 emit_resx (&eh_seq
, tf
->region
);
1448 finally
= gimple_eh_else_n_body (eh_else
);
1450 else if (tf
->may_throw
)
1452 emit_post_landing_pad (&eh_seq
, tf
->region
);
1454 x
= gimple_build_assign (finally_tmp
,
1455 build_int_cst (integer_type_node
, eh_index
));
1456 gimple_seq_add_stmt (&eh_seq
, x
);
1458 x
= gimple_build_goto (finally_label
);
1459 gimple_set_location (x
, tf_loc
);
1460 gimple_seq_add_stmt (&eh_seq
, x
);
1462 tmp
= build_int_cst (integer_type_node
, eh_index
);
1463 last_case
= build_case_label (tmp
, NULL
,
1464 create_artificial_label (tf_loc
));
1465 case_label_vec
.quick_push (last_case
);
1468 x
= gimple_build_label (CASE_LABEL (last_case
));
1469 gimple_seq_add_stmt (&eh_seq
, x
);
1470 emit_resx (&eh_seq
, tf
->region
);
1473 x
= gimple_build_label (finally_label
);
1474 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1476 lower_eh_constructs_1 (state
, &finally
);
1477 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1479 /* Redirect each incoming goto edge. */
1481 qe
= q
+ tf
->goto_queue_active
;
1482 j
= last_case_index
+ tf
->may_return
;
1483 /* Prepare the assignments to finally_tmp that are executed upon the
1484 entrance through a particular edge. */
1487 gimple_seq mod
= NULL
;
1489 unsigned int case_index
;
1493 x
= gimple_build_assign (finally_tmp
,
1494 build_int_cst (integer_type_node
,
1496 gimple_seq_add_stmt (&mod
, x
);
1497 do_return_redirection (q
, finally_label
, mod
);
1498 switch_id
= return_index
;
1502 x
= gimple_build_assign (finally_tmp
,
1503 build_int_cst (integer_type_node
, q
->index
));
1504 gimple_seq_add_stmt (&mod
, x
);
1505 do_goto_redirection (q
, finally_label
, mod
, tf
);
1506 switch_id
= q
->index
;
1509 case_index
= j
+ q
->index
;
1510 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1513 tmp
= build_int_cst (integer_type_node
, switch_id
);
1514 case_lab
= build_case_label (tmp
, NULL
,
1515 create_artificial_label (tf_loc
));
1516 /* We store the cont_stmt in the pointer map, so that we can recover
1517 it in the loop below. */
1519 cont_map
= new hash_map
<tree
, gimple
*>;
1520 cont_map
->put (case_lab
, q
->cont_stmt
);
1521 case_label_vec
.quick_push (case_lab
);
1524 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1528 last_case
= case_label_vec
[j
];
1530 gcc_assert (last_case
);
1531 gcc_assert (cont_map
);
1533 cont_stmt
= *cont_map
->get (last_case
);
1535 x
= gimple_build_label (CASE_LABEL (last_case
));
1536 gimple_seq_add_stmt (&switch_body
, x
);
1537 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1538 maybe_record_in_goto_queue (state
, cont_stmt
);
1543 replace_goto_queue (tf
);
1545 /* Make sure that the last case is the default label, as one is required.
1546 Then sort the labels, which is also required in GIMPLE. */
1547 CASE_LOW (last_case
) = NULL
;
1548 tree tem
= case_label_vec
.pop ();
1549 gcc_assert (tem
== last_case
);
1550 sort_case_labels (case_label_vec
);
1552 /* Build the switch statement, setting last_case to be the default
1554 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1556 gimple_set_location (switch_stmt
, finally_loc
);
1558 /* Need to link SWITCH_STMT after running replace_goto_queue
1559 due to not wanting to process the same goto stmts twice. */
1560 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1561 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1564 /* Decide whether or not we are going to duplicate the finally block.
1565 There are several considerations.
1567 First, if this is Java, then the finally block contains code
1568 written by the user. It has line numbers associated with it,
1569 so duplicating the block means it's difficult to set a breakpoint.
1570 Since controlling code generation via -g is verboten, we simply
1571 never duplicate code without optimization.
1573 Second, we'd like to prevent egregious code growth. One way to
1574 do this is to estimate the size of the finally block, multiply
1575 that by the number of copies we'd need to make, and compare against
1576 the estimate of the size of the switch machinery we'd have to add. */
1579 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1581 int f_estimate
, sw_estimate
;
1584 /* If there's an EH_ELSE involved, the exception path is separate
1585 and really doesn't come into play for this computation. */
1586 eh_else
= get_eh_else (finally
);
1589 ndests
-= may_throw
;
1590 finally
= gimple_eh_else_n_body (eh_else
);
1595 gimple_stmt_iterator gsi
;
1600 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1602 /* Duplicate __builtin_stack_restore in the hope of eliminating it
1603 on the EH paths and, consequently, useless cleanups. */
1604 gimple
*stmt
= gsi_stmt (gsi
);
1605 if (!is_gimple_debug (stmt
)
1606 && !gimple_clobber_p (stmt
)
1607 && !gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
1613 /* Finally estimate N times, plus N gotos. */
1614 f_estimate
= estimate_num_insns_seq (finally
, &eni_size_weights
);
1615 f_estimate
= (f_estimate
+ 1) * ndests
;
1617 /* Switch statement (cost 10), N variable assignments, N gotos. */
1618 sw_estimate
= 10 + 2 * ndests
;
1620 /* Optimize for size clearly wants our best guess. */
1621 if (optimize_function_for_size_p (cfun
))
1622 return f_estimate
< sw_estimate
;
1624 /* ??? These numbers are completely made up so far. */
1626 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1628 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1631 /* REG 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 (eh_region reg
)
1641 while (reg
&& reg
->type
== ERT_CLEANUP
)
1643 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1646 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1647 to a sequence of labels and blocks, plus the exception region trees
1648 that record all the magic. This is complicated by the need to
1649 arrange for the FINALLY block to be executed on all exits. */
1652 lower_try_finally (struct leh_state
*state
, gtry
*tp
)
1654 struct leh_tf_state this_tf
;
1655 struct leh_state this_state
;
1657 gimple_seq old_eh_seq
;
1659 /* Process the try block. */
1661 memset (&this_tf
, 0, sizeof (this_tf
));
1662 this_tf
.try_finally_expr
= tp
;
1664 this_tf
.outer
= state
;
1665 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
->cur_region
))
1667 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1668 this_state
.cur_region
= this_tf
.region
;
1672 this_tf
.region
= NULL
;
1673 this_state
.cur_region
= state
->cur_region
;
1676 this_state
.ehp_region
= state
->ehp_region
;
1677 this_state
.tf
= &this_tf
;
1679 old_eh_seq
= eh_seq
;
1682 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1684 /* Determine if the try block is escaped through the bottom. */
1685 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1687 /* Determine if any exceptions are possible within the try block. */
1689 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1690 if (this_tf
.may_throw
)
1691 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1693 /* Determine how many edges (still) reach the finally block. Or rather,
1694 how many destinations are reached by the finally block. Use this to
1695 determine how we process the finally block itself. */
1697 ndests
= this_tf
.dest_array
.length ();
1698 ndests
+= this_tf
.may_fallthru
;
1699 ndests
+= this_tf
.may_return
;
1700 ndests
+= this_tf
.may_throw
;
1702 /* If the FINALLY block is not reachable, dike it out. */
1705 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1706 gimple_try_set_cleanup (tp
, NULL
);
1708 /* If the finally block doesn't fall through, then any destination
1709 we might try to impose there isn't reached either. There may be
1710 some minor amount of cleanup and redirection still needed. */
1711 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1712 lower_try_finally_nofallthru (state
, &this_tf
);
1714 /* We can easily special-case redirection to a single destination. */
1715 else if (ndests
== 1)
1716 lower_try_finally_onedest (state
, &this_tf
);
1717 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1718 gimple_try_cleanup (tp
)))
1719 lower_try_finally_copy (state
, &this_tf
);
1721 lower_try_finally_switch (state
, &this_tf
);
1723 /* If someone requested we add a label at the end of the transformed
1725 if (this_tf
.fallthru_label
)
1727 /* This must be reached only if ndests == 0. */
1728 gimple
*x
= gimple_build_label (this_tf
.fallthru_label
);
1729 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1732 this_tf
.dest_array
.release ();
1733 free (this_tf
.goto_queue
);
1734 if (this_tf
.goto_queue_map
)
1735 delete this_tf
.goto_queue_map
;
1737 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1738 If there was no old eh_seq, then the append is trivially already done. */
1742 eh_seq
= old_eh_seq
;
1745 gimple_seq new_eh_seq
= eh_seq
;
1746 eh_seq
= old_eh_seq
;
1747 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1751 return this_tf
.top_p_seq
;
1754 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1755 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1756 exception region trees that records all the magic. */
1759 lower_catch (struct leh_state
*state
, gtry
*tp
)
1761 eh_region try_region
= NULL
;
1762 struct leh_state this_state
= *state
;
1763 gimple_stmt_iterator gsi
;
1765 gimple_seq new_seq
, cleanup
;
1767 location_t try_catch_loc
= gimple_location (tp
);
1769 if (flag_exceptions
)
1771 try_region
= gen_eh_region_try (state
->cur_region
);
1772 this_state
.cur_region
= try_region
;
1775 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1777 if (!eh_region_may_contain_throw (try_region
))
1778 return gimple_try_eval (tp
);
1781 emit_eh_dispatch (&new_seq
, try_region
);
1782 emit_resx (&new_seq
, try_region
);
1784 this_state
.cur_region
= state
->cur_region
;
1785 this_state
.ehp_region
= try_region
;
1787 /* Add eh_seq from lowering EH in the cleanup sequence after the cleanup
1788 itself, so that e.g. for coverage purposes the nested cleanups don't
1789 appear before the cleanup body. See PR64634 for details. */
1790 gimple_seq old_eh_seq
= eh_seq
;
1794 cleanup
= gimple_try_cleanup (tp
);
1795 for (gsi
= gsi_start (cleanup
);
1803 catch_stmt
= as_a
<gcatch
*> (gsi_stmt (gsi
));
1804 c
= gen_eh_region_catch (try_region
, gimple_catch_types (catch_stmt
));
1806 handler
= gimple_catch_handler (catch_stmt
);
1807 lower_eh_constructs_1 (&this_state
, &handler
);
1809 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1810 x
= gimple_build_label (c
->label
);
1811 gimple_seq_add_stmt (&new_seq
, x
);
1813 gimple_seq_add_seq (&new_seq
, handler
);
1815 if (gimple_seq_may_fallthru (new_seq
))
1818 out_label
= create_artificial_label (try_catch_loc
);
1820 x
= gimple_build_goto (out_label
);
1821 gimple_seq_add_stmt (&new_seq
, x
);
1827 gimple_try_set_cleanup (tp
, new_seq
);
1829 gimple_seq new_eh_seq
= eh_seq
;
1830 eh_seq
= old_eh_seq
;
1831 gimple_seq ret_seq
= frob_into_branch_around (tp
, try_region
, out_label
);
1832 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1836 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1837 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1838 region trees that record all the magic. */
1841 lower_eh_filter (struct leh_state
*state
, gtry
*tp
)
1843 struct leh_state this_state
= *state
;
1844 eh_region this_region
= NULL
;
1848 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1850 if (flag_exceptions
)
1852 this_region
= gen_eh_region_allowed (state
->cur_region
,
1853 gimple_eh_filter_types (inner
));
1854 this_state
.cur_region
= this_region
;
1857 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1859 if (!eh_region_may_contain_throw (this_region
))
1860 return gimple_try_eval (tp
);
1863 this_state
.cur_region
= state
->cur_region
;
1864 this_state
.ehp_region
= this_region
;
1866 emit_eh_dispatch (&new_seq
, this_region
);
1867 emit_resx (&new_seq
, this_region
);
1869 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1870 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1871 gimple_seq_add_stmt (&new_seq
, x
);
1873 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1874 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1876 gimple_try_set_cleanup (tp
, new_seq
);
1878 return frob_into_branch_around (tp
, this_region
, NULL
);
1881 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1882 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1883 plus the exception region trees that record all the magic. */
1886 lower_eh_must_not_throw (struct leh_state
*state
, gtry
*tp
)
1888 struct leh_state this_state
= *state
;
1890 if (flag_exceptions
)
1892 gimple
*inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1893 eh_region this_region
;
1895 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1896 this_region
->u
.must_not_throw
.failure_decl
1897 = gimple_eh_must_not_throw_fndecl (
1898 as_a
<geh_mnt
*> (inner
));
1899 this_region
->u
.must_not_throw
.failure_loc
1900 = LOCATION_LOCUS (gimple_location (tp
));
1902 /* In order to get mangling applied to this decl, we must mark it
1903 used now. Otherwise, pass_ipa_free_lang_data won't think it
1905 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1907 this_state
.cur_region
= this_region
;
1910 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1912 return gimple_try_eval (tp
);
1915 /* Implement a cleanup expression. This is similar to try-finally,
1916 except that we only execute the cleanup block for exception edges. */
1919 lower_cleanup (struct leh_state
*state
, gtry
*tp
)
1921 struct leh_state this_state
= *state
;
1922 eh_region this_region
= NULL
;
1923 struct leh_tf_state fake_tf
;
1925 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1927 if (flag_exceptions
&& !cleanup_dead
)
1929 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1930 this_state
.cur_region
= this_region
;
1933 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1935 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1936 return gimple_try_eval (tp
);
1938 /* Build enough of a try-finally state so that we can reuse
1939 honor_protect_cleanup_actions. */
1940 memset (&fake_tf
, 0, sizeof (fake_tf
));
1941 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1942 fake_tf
.outer
= state
;
1943 fake_tf
.region
= this_region
;
1944 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1945 fake_tf
.may_throw
= true;
1947 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1949 if (fake_tf
.may_throw
)
1951 /* In this case honor_protect_cleanup_actions had nothing to do,
1952 and we should process this normally. */
1953 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1954 result
= frob_into_branch_around (tp
, this_region
,
1955 fake_tf
.fallthru_label
);
1959 /* In this case honor_protect_cleanup_actions did nearly all of
1960 the work. All we have left is to append the fallthru_label. */
1962 result
= gimple_try_eval (tp
);
1963 if (fake_tf
.fallthru_label
)
1965 gimple
*x
= gimple_build_label (fake_tf
.fallthru_label
);
1966 gimple_seq_add_stmt (&result
, x
);
1972 /* Main loop for lowering eh constructs. Also moves gsi to the next
1976 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1980 gimple
*stmt
= gsi_stmt (*gsi
);
1982 switch (gimple_code (stmt
))
1986 tree fndecl
= gimple_call_fndecl (stmt
);
1989 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1990 switch (DECL_FUNCTION_CODE (fndecl
))
1992 case BUILT_IN_EH_POINTER
:
1993 /* The front end may have generated a call to
1994 __builtin_eh_pointer (0) within a catch region. Replace
1995 this zero argument with the current catch region number. */
1996 if (state
->ehp_region
)
1998 tree nr
= build_int_cst (integer_type_node
,
1999 state
->ehp_region
->index
);
2000 gimple_call_set_arg (stmt
, 0, nr
);
2004 /* The user has dome something silly. Remove it. */
2005 rhs
= null_pointer_node
;
2010 case BUILT_IN_EH_FILTER
:
2011 /* ??? This should never appear, but since it's a builtin it
2012 is accessible to abuse by users. Just remove it and
2013 replace the use with the arbitrary value zero. */
2014 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2016 lhs
= gimple_call_lhs (stmt
);
2017 x
= gimple_build_assign (lhs
, rhs
);
2018 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2021 case BUILT_IN_EH_COPY_VALUES
:
2022 /* Likewise this should not appear. Remove it. */
2023 gsi_remove (gsi
, true);
2033 /* If the stmt can throw use a new temporary for the assignment
2034 to a LHS. This makes sure the old value of the LHS is
2035 available on the EH edge. Only do so for statements that
2036 potentially fall through (no noreturn calls e.g.), otherwise
2037 this new assignment might create fake fallthru regions. */
2038 if (stmt_could_throw_p (stmt
)
2039 && gimple_has_lhs (stmt
)
2040 && gimple_stmt_may_fallthru (stmt
)
2041 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2042 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2044 tree lhs
= gimple_get_lhs (stmt
);
2045 tree tmp
= create_tmp_var (TREE_TYPE (lhs
));
2046 gimple
*s
= gimple_build_assign (lhs
, tmp
);
2047 gimple_set_location (s
, gimple_location (stmt
));
2048 gimple_set_block (s
, gimple_block (stmt
));
2049 gimple_set_lhs (stmt
, tmp
);
2050 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2051 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2052 DECL_GIMPLE_REG_P (tmp
) = 1;
2053 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2055 /* Look for things that can throw exceptions, and record them. */
2056 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
2058 record_stmt_eh_region (state
->cur_region
, stmt
);
2059 note_eh_region_may_contain_throw (state
->cur_region
);
2066 maybe_record_in_goto_queue (state
, stmt
);
2070 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2075 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2076 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2077 replace
= lower_try_finally (state
, try_stmt
);
2080 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2083 replace
= gimple_try_eval (try_stmt
);
2084 lower_eh_constructs_1 (state
, &replace
);
2087 switch (gimple_code (x
))
2090 replace
= lower_catch (state
, try_stmt
);
2092 case GIMPLE_EH_FILTER
:
2093 replace
= lower_eh_filter (state
, try_stmt
);
2095 case GIMPLE_EH_MUST_NOT_THROW
:
2096 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2098 case GIMPLE_EH_ELSE
:
2099 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2102 replace
= lower_cleanup (state
, try_stmt
);
2108 /* Remove the old stmt and insert the transformed sequence
2110 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2111 gsi_remove (gsi
, true);
2113 /* Return since we don't want gsi_next () */
2116 case GIMPLE_EH_ELSE
:
2117 /* We should be eliminating this in lower_try_finally et al. */
2121 /* A type, a decl, or some kind of statement that we're not
2122 interested in. Don't walk them. */
2129 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2132 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2134 gimple_stmt_iterator gsi
;
2135 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2136 lower_eh_constructs_2 (state
, &gsi
);
2141 const pass_data pass_data_lower_eh
=
2143 GIMPLE_PASS
, /* type */
2145 OPTGROUP_NONE
, /* optinfo_flags */
2146 TV_TREE_EH
, /* tv_id */
2147 PROP_gimple_lcf
, /* properties_required */
2148 PROP_gimple_leh
, /* properties_provided */
2149 0, /* properties_destroyed */
2150 0, /* todo_flags_start */
2151 0, /* todo_flags_finish */
2154 class pass_lower_eh
: public gimple_opt_pass
2157 pass_lower_eh (gcc::context
*ctxt
)
2158 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2161 /* opt_pass methods: */
2162 virtual unsigned int execute (function
*);
2164 }; // class pass_lower_eh
2167 pass_lower_eh::execute (function
*fun
)
2169 struct leh_state null_state
;
2172 bodyp
= gimple_body (current_function_decl
);
2176 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2177 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2178 memset (&null_state
, 0, sizeof (null_state
));
2180 collect_finally_tree_1 (bodyp
, NULL
);
2181 lower_eh_constructs_1 (&null_state
, &bodyp
);
2182 gimple_set_body (current_function_decl
, bodyp
);
2184 /* We assume there's a return statement, or something, at the end of
2185 the function, and thus ploping the EH sequence afterward won't
2187 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2188 gimple_seq_add_seq (&bodyp
, eh_seq
);
2190 /* We assume that since BODYP already existed, adding EH_SEQ to it
2191 didn't change its value, and we don't have to re-set the function. */
2192 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2194 delete finally_tree
;
2195 finally_tree
= NULL
;
2196 BITMAP_FREE (eh_region_may_contain_throw_map
);
2199 /* If this function needs a language specific EH personality routine
2200 and the frontend didn't already set one do so now. */
2201 if (function_needs_eh_personality (fun
) == eh_personality_lang
2202 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2203 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2204 = lang_hooks
.eh_personality ();
2212 make_pass_lower_eh (gcc::context
*ctxt
)
2214 return new pass_lower_eh (ctxt
);
2217 /* Create the multiple edges from an EH_DISPATCH statement to all of
2218 the possible handlers for its EH region. Return true if there's
2219 no fallthru edge; false if there is. */
2222 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2226 basic_block src
, dst
;
2228 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2229 src
= gimple_bb (stmt
);
2234 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2236 dst
= label_to_block (c
->label
);
2237 make_edge (src
, dst
, 0);
2239 /* A catch-all handler doesn't have a fallthru. */
2240 if (c
->type_list
== NULL
)
2245 case ERT_ALLOWED_EXCEPTIONS
:
2246 dst
= label_to_block (r
->u
.allowed
.label
);
2247 make_edge (src
, dst
, 0);
2257 /* Create the single EH edge from STMT to its nearest landing pad,
2258 if there is such a landing pad within the current function. */
2261 make_eh_edges (gimple
*stmt
)
2263 basic_block src
, dst
;
2267 lp_nr
= lookup_stmt_eh_lp (stmt
);
2271 lp
= get_eh_landing_pad_from_number (lp_nr
);
2272 gcc_assert (lp
!= NULL
);
2274 src
= gimple_bb (stmt
);
2275 dst
= label_to_block (lp
->post_landing_pad
);
2276 make_edge (src
, dst
, EDGE_EH
);
2279 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2280 do not actually perform the final edge redirection.
2282 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2283 we intend to change the destination EH region as well; this means
2284 EH_LANDING_PAD_NR must already be set on the destination block label.
2285 If false, we're being called from generic cfg manipulation code and we
2286 should preserve our place within the region tree. */
2289 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2291 eh_landing_pad old_lp
, new_lp
;
2294 int old_lp_nr
, new_lp_nr
;
2295 tree old_label
, new_label
;
2299 old_bb
= edge_in
->dest
;
2300 old_label
= gimple_block_label (old_bb
);
2301 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2302 gcc_assert (old_lp_nr
> 0);
2303 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2305 throw_stmt
= last_stmt (edge_in
->src
);
2306 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2308 new_label
= gimple_block_label (new_bb
);
2310 /* Look for an existing region that might be using NEW_BB already. */
2311 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2314 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2315 gcc_assert (new_lp
);
2317 /* Unless CHANGE_REGION is true, the new and old landing pad
2318 had better be associated with the same EH region. */
2319 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2324 gcc_assert (!change_region
);
2327 /* Notice when we redirect the last EH edge away from OLD_BB. */
2328 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2329 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2334 /* NEW_LP already exists. If there are still edges into OLD_LP,
2335 there's nothing to do with the EH tree. If there are no more
2336 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2337 If CHANGE_REGION is true, then our caller is expecting to remove
2339 if (e
== NULL
&& !change_region
)
2340 remove_eh_landing_pad (old_lp
);
2344 /* No correct landing pad exists. If there are no more edges
2345 into OLD_LP, then we can simply re-use the existing landing pad.
2346 Otherwise, we have to create a new landing pad. */
2349 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2353 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2354 new_lp
->post_landing_pad
= new_label
;
2355 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2358 /* Maybe move the throwing statement to the new region. */
2359 if (old_lp
!= new_lp
)
2361 remove_stmt_from_eh_lp (throw_stmt
);
2362 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2366 /* Redirect EH edge E to NEW_BB. */
2369 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2371 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2372 return ssa_redirect_edge (edge_in
, new_bb
);
2375 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2376 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2377 The actual edge update will happen in the caller. */
2380 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2382 tree new_lab
= gimple_block_label (new_bb
);
2383 bool any_changed
= false;
2388 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2392 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2394 old_bb
= label_to_block (c
->label
);
2395 if (old_bb
== e
->dest
)
2403 case ERT_ALLOWED_EXCEPTIONS
:
2404 old_bb
= label_to_block (r
->u
.allowed
.label
);
2405 gcc_assert (old_bb
== e
->dest
);
2406 r
->u
.allowed
.label
= new_lab
;
2414 gcc_assert (any_changed
);
2417 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2420 operation_could_trap_helper_p (enum tree_code op
,
2431 case TRUNC_DIV_EXPR
:
2433 case FLOOR_DIV_EXPR
:
2434 case ROUND_DIV_EXPR
:
2435 case EXACT_DIV_EXPR
:
2437 case FLOOR_MOD_EXPR
:
2438 case ROUND_MOD_EXPR
:
2439 case TRUNC_MOD_EXPR
:
2441 if (honor_snans
|| honor_trapv
)
2444 return flag_trapping_math
;
2445 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2454 /* Some floating point comparisons may trap. */
2459 case UNORDERED_EXPR
:
2471 /* These operations don't trap with floating point. */
2479 /* Any floating arithmetic may trap. */
2480 if (fp_operation
&& flag_trapping_math
)
2488 /* Constructing an object cannot trap. */
2492 /* Any floating arithmetic may trap. */
2493 if (fp_operation
&& flag_trapping_math
)
2501 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2502 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2503 type operands that may trap. If OP is a division operator, DIVISOR contains
2504 the value of the divisor. */
2507 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2510 bool honor_nans
= (fp_operation
&& flag_trapping_math
2511 && !flag_finite_math_only
);
2512 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2515 if (TREE_CODE_CLASS (op
) != tcc_comparison
2516 && TREE_CODE_CLASS (op
) != tcc_unary
2517 && TREE_CODE_CLASS (op
) != tcc_binary
2521 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2522 honor_nans
, honor_snans
, divisor
,
2527 /* Returns true if it is possible to prove that the index of
2528 an array access REF (an ARRAY_REF expression) falls into the
2532 in_array_bounds_p (tree ref
)
2534 tree idx
= TREE_OPERAND (ref
, 1);
2537 if (TREE_CODE (idx
) != INTEGER_CST
)
2540 min
= array_ref_low_bound (ref
);
2541 max
= array_ref_up_bound (ref
);
2544 || TREE_CODE (min
) != INTEGER_CST
2545 || TREE_CODE (max
) != INTEGER_CST
)
2548 if (tree_int_cst_lt (idx
, min
)
2549 || tree_int_cst_lt (max
, idx
))
2555 /* Returns true if it is possible to prove that the range of
2556 an array access REF (an ARRAY_RANGE_REF expression) falls
2557 into the array bounds. */
2560 range_in_array_bounds_p (tree ref
)
2562 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2563 tree range_min
, range_max
, min
, max
;
2565 range_min
= TYPE_MIN_VALUE (domain_type
);
2566 range_max
= TYPE_MAX_VALUE (domain_type
);
2569 || TREE_CODE (range_min
) != INTEGER_CST
2570 || TREE_CODE (range_max
) != INTEGER_CST
)
2573 min
= array_ref_low_bound (ref
);
2574 max
= array_ref_up_bound (ref
);
2577 || TREE_CODE (min
) != INTEGER_CST
2578 || TREE_CODE (max
) != INTEGER_CST
)
2581 if (tree_int_cst_lt (range_min
, min
)
2582 || tree_int_cst_lt (max
, range_max
))
2588 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2589 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2590 This routine expects only GIMPLE lhs or rhs input. */
2593 tree_could_trap_p (tree expr
)
2595 enum tree_code code
;
2596 bool fp_operation
= false;
2597 bool honor_trapv
= false;
2598 tree t
, base
, div
= NULL_TREE
;
2603 code
= TREE_CODE (expr
);
2604 t
= TREE_TYPE (expr
);
2608 if (COMPARISON_CLASS_P (expr
))
2609 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2611 fp_operation
= FLOAT_TYPE_P (t
);
2612 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2615 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2616 div
= TREE_OPERAND (expr
, 1);
2617 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2627 case VIEW_CONVERT_EXPR
:
2628 case WITH_SIZE_EXPR
:
2629 expr
= TREE_OPERAND (expr
, 0);
2630 code
= TREE_CODE (expr
);
2633 case ARRAY_RANGE_REF
:
2634 base
= TREE_OPERAND (expr
, 0);
2635 if (tree_could_trap_p (base
))
2637 if (TREE_THIS_NOTRAP (expr
))
2639 return !range_in_array_bounds_p (expr
);
2642 base
= TREE_OPERAND (expr
, 0);
2643 if (tree_could_trap_p (base
))
2645 if (TREE_THIS_NOTRAP (expr
))
2647 return !in_array_bounds_p (expr
);
2649 case TARGET_MEM_REF
:
2651 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2652 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2654 if (TREE_THIS_NOTRAP (expr
))
2656 /* We cannot prove that the access is in-bounds when we have
2657 variable-index TARGET_MEM_REFs. */
2658 if (code
== TARGET_MEM_REF
2659 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2661 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2663 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2664 offset_int off
= mem_ref_offset (expr
);
2665 if (wi::neg_p (off
, SIGNED
))
2667 if (TREE_CODE (base
) == STRING_CST
)
2668 return wi::leu_p (TREE_STRING_LENGTH (base
), off
);
2669 else if (DECL_SIZE_UNIT (base
) == NULL_TREE
2670 || TREE_CODE (DECL_SIZE_UNIT (base
)) != INTEGER_CST
2671 || wi::leu_p (wi::to_offset (DECL_SIZE_UNIT (base
)), off
))
2673 /* Now we are sure the first byte of the access is inside
2680 return !TREE_THIS_NOTRAP (expr
);
2683 return TREE_THIS_VOLATILE (expr
);
2686 t
= get_callee_fndecl (expr
);
2687 /* Assume that calls to weak functions may trap. */
2688 if (!t
|| !DECL_P (t
))
2691 return tree_could_trap_p (t
);
2695 /* Assume that accesses to weak functions may trap, unless we know
2696 they are certainly defined in current TU or in some other
2698 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2700 cgraph_node
*node
= cgraph_node::get (expr
);
2702 node
= node
->function_symbol ();
2703 return !(node
&& node
->in_other_partition
);
2708 /* Assume that accesses to weak vars may trap, unless we know
2709 they are certainly defined in current TU or in some other
2711 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2713 varpool_node
*node
= varpool_node::get (expr
);
2715 node
= node
->ultimate_alias_target ();
2716 return !(node
&& node
->in_other_partition
);
2726 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2727 an assignment or a conditional) may throw. */
2730 stmt_could_throw_1_p (gassign
*stmt
)
2732 enum tree_code code
= gimple_assign_rhs_code (stmt
);
2733 bool honor_nans
= false;
2734 bool honor_snans
= false;
2735 bool fp_operation
= false;
2736 bool honor_trapv
= false;
2741 if (TREE_CODE_CLASS (code
) == tcc_comparison
2742 || TREE_CODE_CLASS (code
) == tcc_unary
2743 || TREE_CODE_CLASS (code
) == tcc_binary
2744 || code
== FMA_EXPR
)
2746 if (TREE_CODE_CLASS (code
) == tcc_comparison
)
2747 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2749 t
= gimple_expr_type (stmt
);
2750 fp_operation
= FLOAT_TYPE_P (t
);
2753 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2754 honor_snans
= flag_signaling_nans
!= 0;
2756 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2760 /* First check the LHS. */
2761 if (tree_could_trap_p (gimple_assign_lhs (stmt
)))
2764 /* Check if the main expression may trap. */
2765 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2766 honor_nans
, honor_snans
,
2767 gimple_assign_rhs2 (stmt
),
2772 /* If the expression does not trap, see if any of the individual operands may
2774 for (i
= 1; i
< gimple_num_ops (stmt
); i
++)
2775 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2782 /* Return true if statement STMT could throw an exception. */
2785 stmt_could_throw_p (gimple
*stmt
)
2787 if (!flag_exceptions
)
2790 /* The only statements that can throw an exception are assignments,
2791 conditionals, calls, resx, and asms. */
2792 switch (gimple_code (stmt
))
2798 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2802 if (!cfun
->can_throw_non_call_exceptions
)
2804 gcond
*cond
= as_a
<gcond
*> (stmt
);
2805 tree lhs
= gimple_cond_lhs (cond
);
2806 return operation_could_trap_p (gimple_cond_code (cond
),
2807 FLOAT_TYPE_P (TREE_TYPE (lhs
)),
2812 if (!cfun
->can_throw_non_call_exceptions
2813 || gimple_clobber_p (stmt
))
2815 return stmt_could_throw_1_p (as_a
<gassign
*> (stmt
));
2818 if (!cfun
->can_throw_non_call_exceptions
)
2820 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2828 /* Return true if expression T could throw an exception. */
2831 tree_could_throw_p (tree t
)
2833 if (!flag_exceptions
)
2835 if (TREE_CODE (t
) == MODIFY_EXPR
)
2837 if (cfun
->can_throw_non_call_exceptions
2838 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2840 t
= TREE_OPERAND (t
, 1);
2843 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2844 t
= TREE_OPERAND (t
, 0);
2845 if (TREE_CODE (t
) == CALL_EXPR
)
2846 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2847 if (cfun
->can_throw_non_call_exceptions
)
2848 return tree_could_trap_p (t
);
2852 /* Return true if STMT can throw an exception that is not caught within
2853 the current function (CFUN). */
2856 stmt_can_throw_external (gimple
*stmt
)
2860 if (!stmt_could_throw_p (stmt
))
2863 lp_nr
= lookup_stmt_eh_lp (stmt
);
2867 /* Return true if STMT can throw an exception that is caught within
2868 the current function (CFUN). */
2871 stmt_can_throw_internal (gimple
*stmt
)
2875 if (!stmt_could_throw_p (stmt
))
2878 lp_nr
= lookup_stmt_eh_lp (stmt
);
2882 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2883 remove any entry it might have from the EH table. Return true if
2884 any change was made. */
2887 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple
*stmt
)
2889 if (stmt_could_throw_p (stmt
))
2891 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2894 /* Likewise, but always use the current function. */
2897 maybe_clean_eh_stmt (gimple
*stmt
)
2899 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2902 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2903 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2904 in the table if it should be in there. Return TRUE if a replacement was
2905 done that my require an EH edge purge. */
2908 maybe_clean_or_replace_eh_stmt (gimple
*old_stmt
, gimple
*new_stmt
)
2910 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2914 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2916 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2919 remove_stmt_from_eh_lp (old_stmt
);
2920 if (new_stmt_could_throw
)
2922 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2932 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2933 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2934 operand is the return value of duplicate_eh_regions. */
2937 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple
*new_stmt
,
2938 struct function
*old_fun
, gimple
*old_stmt
,
2939 hash_map
<void *, void *> *map
,
2942 int old_lp_nr
, new_lp_nr
;
2944 if (!stmt_could_throw_p (new_stmt
))
2947 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2950 if (default_lp_nr
== 0)
2952 new_lp_nr
= default_lp_nr
;
2954 else if (old_lp_nr
> 0)
2956 eh_landing_pad old_lp
, new_lp
;
2958 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
2959 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
2960 new_lp_nr
= new_lp
->index
;
2964 eh_region old_r
, new_r
;
2966 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
2967 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
2968 new_lp_nr
= -new_r
->index
;
2971 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2975 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2976 and thus no remapping is required. */
2979 maybe_duplicate_eh_stmt (gimple
*new_stmt
, gimple
*old_stmt
)
2983 if (!stmt_could_throw_p (new_stmt
))
2986 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2990 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2994 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2995 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2996 this only handles handlers consisting of a single call, as that's the
2997 important case for C++: a destructor call for a particular object showing
2998 up in multiple handlers. */
3001 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
3003 gimple_stmt_iterator gsi
;
3004 gimple
*ones
, *twos
;
3007 gsi
= gsi_start (oneh
);
3008 if (!gsi_one_before_end_p (gsi
))
3010 ones
= gsi_stmt (gsi
);
3012 gsi
= gsi_start (twoh
);
3013 if (!gsi_one_before_end_p (gsi
))
3015 twos
= gsi_stmt (gsi
);
3017 if (!is_gimple_call (ones
)
3018 || !is_gimple_call (twos
)
3019 || gimple_call_lhs (ones
)
3020 || gimple_call_lhs (twos
)
3021 || gimple_call_chain (ones
)
3022 || gimple_call_chain (twos
)
3023 || !gimple_call_same_target_p (ones
, twos
)
3024 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3027 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3028 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3029 gimple_call_arg (twos
, ai
), 0))
3036 try { A() } finally { try { ~B() } catch { ~A() } }
3037 try { ... } finally { ~A() }
3039 try { A() } catch { ~B() }
3040 try { ~B() ... } finally { ~A() }
3042 This occurs frequently in C++, where A is a local variable and B is a
3043 temporary used in the initializer for A. */
3046 optimize_double_finally (gtry
*one
, gtry
*two
)
3049 gimple_stmt_iterator gsi
;
3052 cleanup
= gimple_try_cleanup (one
);
3053 gsi
= gsi_start (cleanup
);
3054 if (!gsi_one_before_end_p (gsi
))
3057 oneh
= gsi_stmt (gsi
);
3058 if (gimple_code (oneh
) != GIMPLE_TRY
3059 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3062 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3064 gimple_seq seq
= gimple_try_eval (oneh
);
3066 gimple_try_set_cleanup (one
, seq
);
3067 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3068 seq
= copy_gimple_seq_and_replace_locals (seq
);
3069 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3070 gimple_try_set_eval (two
, seq
);
3074 /* Perform EH refactoring optimizations that are simpler to do when code
3075 flow has been lowered but EH structures haven't. */
3078 refactor_eh_r (gimple_seq seq
)
3080 gimple_stmt_iterator gsi
;
3085 gsi
= gsi_start (seq
);
3089 if (gsi_end_p (gsi
))
3092 two
= gsi_stmt (gsi
);
3094 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3095 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3096 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3097 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3098 optimize_double_finally (try_one
, try_two
);
3100 switch (gimple_code (one
))
3103 refactor_eh_r (gimple_try_eval (one
));
3104 refactor_eh_r (gimple_try_cleanup (one
));
3107 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3109 case GIMPLE_EH_FILTER
:
3110 refactor_eh_r (gimple_eh_filter_failure (one
));
3112 case GIMPLE_EH_ELSE
:
3114 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3115 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3116 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3131 const pass_data pass_data_refactor_eh
=
3133 GIMPLE_PASS
, /* type */
3135 OPTGROUP_NONE
, /* optinfo_flags */
3136 TV_TREE_EH
, /* tv_id */
3137 PROP_gimple_lcf
, /* properties_required */
3138 0, /* properties_provided */
3139 0, /* properties_destroyed */
3140 0, /* todo_flags_start */
3141 0, /* todo_flags_finish */
3144 class pass_refactor_eh
: public gimple_opt_pass
3147 pass_refactor_eh (gcc::context
*ctxt
)
3148 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3151 /* opt_pass methods: */
3152 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3153 virtual unsigned int execute (function
*)
3155 refactor_eh_r (gimple_body (current_function_decl
));
3159 }; // class pass_refactor_eh
3164 make_pass_refactor_eh (gcc::context
*ctxt
)
3166 return new pass_refactor_eh (ctxt
);
3169 /* At the end of gimple optimization, we can lower RESX. */
3172 lower_resx (basic_block bb
, gresx
*stmt
,
3173 hash_map
<eh_region
, tree
> *mnt_map
)
3176 eh_region src_r
, dst_r
;
3177 gimple_stmt_iterator gsi
;
3182 lp_nr
= lookup_stmt_eh_lp (stmt
);
3184 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3188 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3189 gsi
= gsi_last_bb (bb
);
3193 /* We can wind up with no source region when pass_cleanup_eh shows
3194 that there are no entries into an eh region and deletes it, but
3195 then the block that contains the resx isn't removed. This can
3196 happen without optimization when the switch statement created by
3197 lower_try_finally_switch isn't simplified to remove the eh case.
3199 Resolve this by expanding the resx node to an abort. */
3201 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3202 x
= gimple_build_call (fn
, 0);
3203 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3205 while (EDGE_COUNT (bb
->succs
) > 0)
3206 remove_edge (EDGE_SUCC (bb
, 0));
3210 /* When we have a destination region, we resolve this by copying
3211 the excptr and filter values into place, and changing the edge
3212 to immediately after the landing pad. */
3220 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3221 the failure decl into a new block, if needed. */
3222 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3224 tree
*slot
= mnt_map
->get (dst_r
);
3227 gimple_stmt_iterator gsi2
;
3229 new_bb
= create_empty_bb (bb
);
3230 add_bb_to_loop (new_bb
, bb
->loop_father
);
3231 lab
= gimple_block_label (new_bb
);
3232 gsi2
= gsi_start_bb (new_bb
);
3234 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3235 x
= gimple_build_call (fn
, 0);
3236 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3237 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3239 mnt_map
->put (dst_r
, lab
);
3244 new_bb
= label_to_block (lab
);
3247 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3248 e
= make_single_succ_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3253 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3255 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3256 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3257 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3258 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3260 /* Update the flags for the outgoing edge. */
3261 e
= single_succ_edge (bb
);
3262 gcc_assert (e
->flags
& EDGE_EH
);
3263 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3264 e
->probability
= profile_probability::always ();
3265 e
->count
= bb
->count
;
3267 /* If there are no more EH users of the landing pad, delete it. */
3268 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3269 if (e
->flags
& EDGE_EH
)
3273 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3274 remove_eh_landing_pad (lp
);
3284 /* When we don't have a destination region, this exception escapes
3285 up the call chain. We resolve this by generating a call to the
3286 _Unwind_Resume library function. */
3288 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3289 with no arguments for C++ and Java. Check for that. */
3290 if (src_r
->use_cxa_end_cleanup
)
3292 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3293 x
= gimple_build_call (fn
, 0);
3294 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3298 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3299 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3300 x
= gimple_build_call (fn
, 1, src_nr
);
3301 var
= create_tmp_var (ptr_type_node
);
3302 var
= make_ssa_name (var
, x
);
3303 gimple_call_set_lhs (x
, var
);
3304 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3306 /* When exception handling is delegated to a caller function, we
3307 have to guarantee that shadow memory variables living on stack
3308 will be cleaner before control is given to a parent function. */
3309 if (sanitize_flags_p (SANITIZE_ADDRESS
))
3312 = builtin_decl_implicit (BUILT_IN_ASAN_HANDLE_NO_RETURN
);
3313 gimple
*g
= gimple_build_call (decl
, 0);
3314 gimple_set_location (g
, gimple_location (stmt
));
3315 gsi_insert_before (&gsi
, g
, GSI_SAME_STMT
);
3318 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3319 x
= gimple_build_call (fn
, 1, var
);
3320 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3323 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3326 gsi_remove (&gsi
, true);
3333 const pass_data pass_data_lower_resx
=
3335 GIMPLE_PASS
, /* type */
3337 OPTGROUP_NONE
, /* optinfo_flags */
3338 TV_TREE_EH
, /* tv_id */
3339 PROP_gimple_lcf
, /* properties_required */
3340 0, /* properties_provided */
3341 0, /* properties_destroyed */
3342 0, /* todo_flags_start */
3343 0, /* todo_flags_finish */
3346 class pass_lower_resx
: public gimple_opt_pass
3349 pass_lower_resx (gcc::context
*ctxt
)
3350 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3353 /* opt_pass methods: */
3354 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3355 virtual unsigned int execute (function
*);
3357 }; // class pass_lower_resx
3360 pass_lower_resx::execute (function
*fun
)
3363 bool dominance_invalidated
= false;
3364 bool any_rewritten
= false;
3366 hash_map
<eh_region
, tree
> mnt_map
;
3368 FOR_EACH_BB_FN (bb
, fun
)
3370 gimple
*last
= last_stmt (bb
);
3371 if (last
&& is_gimple_resx (last
))
3373 dominance_invalidated
|=
3374 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3375 any_rewritten
= true;
3379 if (dominance_invalidated
)
3381 free_dominance_info (CDI_DOMINATORS
);
3382 free_dominance_info (CDI_POST_DOMINATORS
);
3385 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3391 make_pass_lower_resx (gcc::context
*ctxt
)
3393 return new pass_lower_resx (ctxt
);
3396 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3400 optimize_clobbers (basic_block bb
)
3402 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3403 bool any_clobbers
= false;
3404 bool seen_stack_restore
= false;
3408 /* Only optimize anything if the bb contains at least one clobber,
3409 ends with resx (checked by caller), optionally contains some
3410 debug stmts or labels, or at most one __builtin_stack_restore
3411 call, and has an incoming EH edge. */
3412 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3414 gimple
*stmt
= gsi_stmt (gsi
);
3415 if (is_gimple_debug (stmt
))
3417 if (gimple_clobber_p (stmt
))
3419 any_clobbers
= true;
3422 if (!seen_stack_restore
3423 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3425 seen_stack_restore
= true;
3428 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3434 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3435 if (e
->flags
& EDGE_EH
)
3439 gsi
= gsi_last_bb (bb
);
3440 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3442 gimple
*stmt
= gsi_stmt (gsi
);
3443 if (!gimple_clobber_p (stmt
))
3445 unlink_stmt_vdef (stmt
);
3446 gsi_remove (&gsi
, true);
3447 release_defs (stmt
);
3451 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3452 internal throw to successor BB. */
3455 sink_clobbers (basic_block bb
)
3459 gimple_stmt_iterator gsi
, dgsi
;
3461 bool any_clobbers
= false;
3464 /* Only optimize if BB has a single EH successor and
3465 all predecessor edges are EH too. */
3466 if (!single_succ_p (bb
)
3467 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3470 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3472 if ((e
->flags
& EDGE_EH
) == 0)
3476 /* And BB contains only CLOBBER stmts before the final
3478 gsi
= gsi_last_bb (bb
);
3479 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3481 gimple
*stmt
= gsi_stmt (gsi
);
3482 if (is_gimple_debug (stmt
))
3484 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3486 if (!gimple_clobber_p (stmt
))
3488 any_clobbers
= true;
3493 edge succe
= single_succ_edge (bb
);
3494 succbb
= succe
->dest
;
3496 /* See if there is a virtual PHI node to take an updated virtual
3499 tree vuse
= NULL_TREE
;
3500 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3501 !gsi_end_p (gpi
); gsi_next (&gpi
))
3503 tree res
= gimple_phi_result (gpi
.phi ());
3504 if (virtual_operand_p (res
))
3512 dgsi
= gsi_after_labels (succbb
);
3513 gsi
= gsi_last_bb (bb
);
3514 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3516 gimple
*stmt
= gsi_stmt (gsi
);
3518 if (is_gimple_debug (stmt
))
3520 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3522 lhs
= gimple_assign_lhs (stmt
);
3523 /* Unfortunately we don't have dominance info updated at this
3524 point, so checking if
3525 dominated_by_p (CDI_DOMINATORS, succbb,
3526 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3527 would be too costly. Thus, avoid sinking any clobbers that
3528 refer to non-(D) SSA_NAMEs. */
3529 if (TREE_CODE (lhs
) == MEM_REF
3530 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3531 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3533 unlink_stmt_vdef (stmt
);
3534 gsi_remove (&gsi
, true);
3535 release_defs (stmt
);
3539 /* As we do not change stmt order when sinking across a
3540 forwarder edge we can keep virtual operands in place. */
3541 gsi_remove (&gsi
, false);
3542 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3544 /* But adjust virtual operands if we sunk across a PHI node. */
3548 imm_use_iterator iter
;
3549 use_operand_p use_p
;
3550 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, vuse
)
3551 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3552 SET_USE (use_p
, gimple_vdef (stmt
));
3553 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
))
3555 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt
)) = 1;
3556 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
) = 0;
3558 /* Adjust the incoming virtual operand. */
3559 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
), gimple_vuse (stmt
));
3560 SET_USE (gimple_vuse_op (stmt
), vuse
);
3562 /* If there isn't a single predecessor but no virtual PHI node
3563 arrange for virtual operands to be renamed. */
3564 else if (gimple_vuse_op (stmt
) != NULL_USE_OPERAND_P
3565 && !single_pred_p (succbb
))
3567 /* In this case there will be no use of the VDEF of this stmt.
3568 ??? Unless this is a secondary opportunity and we have not
3569 removed unreachable blocks yet, so we cannot assert this.
3570 Which also means we will end up renaming too many times. */
3571 SET_USE (gimple_vuse_op (stmt
), gimple_vop (cfun
));
3572 mark_virtual_operands_for_renaming (cfun
);
3573 todo
|= TODO_update_ssa_only_virtuals
;
3580 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3581 we have found some duplicate labels and removed some edges. */
3584 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3586 gimple_stmt_iterator gsi
;
3591 bool redirected
= false;
3593 region_nr
= gimple_eh_dispatch_region (stmt
);
3594 r
= get_eh_region_from_number (region_nr
);
3596 gsi
= gsi_last_bb (src
);
3602 auto_vec
<tree
> labels
;
3603 tree default_label
= NULL
;
3607 hash_set
<tree
> seen_values
;
3609 /* Collect the labels for a switch. Zero the post_landing_pad
3610 field becase we'll no longer have anything keeping these labels
3611 in existence and the optimizer will be free to merge these
3613 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3615 tree tp_node
, flt_node
, lab
= c
->label
;
3616 bool have_label
= false;
3619 tp_node
= c
->type_list
;
3620 flt_node
= c
->filter_list
;
3622 if (tp_node
== NULL
)
3624 default_label
= lab
;
3629 /* Filter out duplicate labels that arise when this handler
3630 is shadowed by an earlier one. When no labels are
3631 attached to the handler anymore, we remove
3632 the corresponding edge and then we delete unreachable
3633 blocks at the end of this pass. */
3634 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3636 tree t
= build_case_label (TREE_VALUE (flt_node
),
3638 labels
.safe_push (t
);
3639 seen_values
.add (TREE_VALUE (flt_node
));
3643 tp_node
= TREE_CHAIN (tp_node
);
3644 flt_node
= TREE_CHAIN (flt_node
);
3649 remove_edge (find_edge (src
, label_to_block (lab
)));
3654 /* Clean up the edge flags. */
3655 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3657 if (e
->flags
& EDGE_FALLTHRU
)
3659 /* If there was no catch-all, use the fallthru edge. */
3660 if (default_label
== NULL
)
3661 default_label
= gimple_block_label (e
->dest
);
3662 e
->flags
&= ~EDGE_FALLTHRU
;
3665 gcc_assert (default_label
!= NULL
);
3667 /* Don't generate a switch if there's only a default case.
3668 This is common in the form of try { A; } catch (...) { B; }. */
3669 if (!labels
.exists ())
3671 e
= single_succ_edge (src
);
3672 e
->flags
|= EDGE_FALLTHRU
;
3676 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3677 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3679 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3680 filter
= make_ssa_name (filter
, x
);
3681 gimple_call_set_lhs (x
, filter
);
3682 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3684 /* Turn the default label into a default case. */
3685 default_label
= build_case_label (NULL
, NULL
, default_label
);
3686 sort_case_labels (labels
);
3688 x
= gimple_build_switch (filter
, default_label
, labels
);
3689 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3694 case ERT_ALLOWED_EXCEPTIONS
:
3696 edge b_e
= BRANCH_EDGE (src
);
3697 edge f_e
= FALLTHRU_EDGE (src
);
3699 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3700 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3702 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3703 filter
= make_ssa_name (filter
, x
);
3704 gimple_call_set_lhs (x
, filter
);
3705 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3707 r
->u
.allowed
.label
= NULL
;
3708 x
= gimple_build_cond (EQ_EXPR
, filter
,
3709 build_int_cst (TREE_TYPE (filter
),
3710 r
->u
.allowed
.filter
),
3711 NULL_TREE
, NULL_TREE
);
3712 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3714 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3715 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3723 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3724 gsi_remove (&gsi
, true);
3730 const pass_data pass_data_lower_eh_dispatch
=
3732 GIMPLE_PASS
, /* type */
3733 "ehdisp", /* name */
3734 OPTGROUP_NONE
, /* optinfo_flags */
3735 TV_TREE_EH
, /* tv_id */
3736 PROP_gimple_lcf
, /* properties_required */
3737 0, /* properties_provided */
3738 0, /* properties_destroyed */
3739 0, /* todo_flags_start */
3740 0, /* todo_flags_finish */
3743 class pass_lower_eh_dispatch
: public gimple_opt_pass
3746 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3747 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3750 /* opt_pass methods: */
3751 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3752 virtual unsigned int execute (function
*);
3754 }; // class pass_lower_eh_dispatch
3757 pass_lower_eh_dispatch::execute (function
*fun
)
3761 bool redirected
= false;
3763 assign_filter_values ();
3765 FOR_EACH_BB_FN (bb
, fun
)
3767 gimple
*last
= last_stmt (bb
);
3770 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3772 redirected
|= lower_eh_dispatch (bb
,
3773 as_a
<geh_dispatch
*> (last
));
3774 flags
|= TODO_update_ssa_only_virtuals
;
3776 else if (gimple_code (last
) == GIMPLE_RESX
)
3778 if (stmt_can_throw_external (last
))
3779 optimize_clobbers (bb
);
3781 flags
|= sink_clobbers (bb
);
3786 delete_unreachable_blocks ();
3793 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3795 return new pass_lower_eh_dispatch (ctxt
);
3798 /* Walk statements, see what regions and, optionally, landing pads
3799 are really referenced.
3801 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3802 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3804 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3807 The caller is responsible for freeing the returned sbitmaps. */
3810 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3812 sbitmap r_reachable
, lp_reachable
;
3814 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3815 gcc_checking_assert (r_reachablep
!= NULL
);
3817 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3818 bitmap_clear (r_reachable
);
3819 *r_reachablep
= r_reachable
;
3821 if (mark_landing_pads
)
3823 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
3824 bitmap_clear (lp_reachable
);
3825 *lp_reachablep
= lp_reachable
;
3828 lp_reachable
= NULL
;
3830 FOR_EACH_BB_FN (bb
, cfun
)
3832 gimple_stmt_iterator gsi
;
3834 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3836 gimple
*stmt
= gsi_stmt (gsi
);
3838 if (mark_landing_pads
)
3840 int lp_nr
= lookup_stmt_eh_lp (stmt
);
3842 /* Negative LP numbers are MUST_NOT_THROW regions which
3843 are not considered BB enders. */
3845 bitmap_set_bit (r_reachable
, -lp_nr
);
3847 /* Positive LP numbers are real landing pads, and BB enders. */
3850 gcc_assert (gsi_one_before_end_p (gsi
));
3851 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
3852 bitmap_set_bit (r_reachable
, region
->index
);
3853 bitmap_set_bit (lp_reachable
, lp_nr
);
3857 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3858 switch (gimple_code (stmt
))
3861 bitmap_set_bit (r_reachable
,
3862 gimple_resx_region (as_a
<gresx
*> (stmt
)));
3864 case GIMPLE_EH_DISPATCH
:
3865 bitmap_set_bit (r_reachable
,
3866 gimple_eh_dispatch_region (
3867 as_a
<geh_dispatch
*> (stmt
)));
3870 if (gimple_call_builtin_p (stmt
, BUILT_IN_EH_COPY_VALUES
))
3871 for (int i
= 0; i
< 2; ++i
)
3873 tree rt
= gimple_call_arg (stmt
, i
);
3874 HOST_WIDE_INT ri
= tree_to_shwi (rt
);
3876 gcc_assert (ri
== (int)ri
);
3877 bitmap_set_bit (r_reachable
, ri
);
3887 /* Remove unreachable handlers and unreachable landing pads. */
3890 remove_unreachable_handlers (void)
3892 sbitmap r_reachable
, lp_reachable
;
3897 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
3901 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3902 dump_eh_tree (dump_file
, cfun
);
3903 fprintf (dump_file
, "Reachable regions: ");
3904 dump_bitmap_file (dump_file
, r_reachable
);
3905 fprintf (dump_file
, "Reachable landing pads: ");
3906 dump_bitmap_file (dump_file
, lp_reachable
);
3911 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3912 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
3914 "Removing unreachable region %d\n",
3918 remove_unreachable_eh_regions (r_reachable
);
3920 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3921 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
3925 "Removing unreachable landing pad %d\n",
3927 remove_eh_landing_pad (lp
);
3932 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3933 dump_eh_tree (dump_file
, cfun
);
3934 fprintf (dump_file
, "\n\n");
3937 sbitmap_free (r_reachable
);
3938 sbitmap_free (lp_reachable
);
3941 verify_eh_tree (cfun
);
3944 /* Remove unreachable handlers if any landing pads have been removed after
3945 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3948 maybe_remove_unreachable_handlers (void)
3953 if (cfun
->eh
== NULL
)
3956 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3957 if (lp
&& lp
->post_landing_pad
)
3959 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3961 remove_unreachable_handlers ();
3967 /* Remove regions that do not have landing pads. This assumes
3968 that remove_unreachable_handlers has already been run, and
3969 that we've just manipulated the landing pads since then.
3971 Preserve regions with landing pads and regions that prevent
3972 exceptions from propagating further, even if these regions
3973 are not reachable. */
3976 remove_unreachable_handlers_no_lp (void)
3979 sbitmap r_reachable
;
3982 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
3984 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3989 if (region
->landing_pads
!= NULL
3990 || region
->type
== ERT_MUST_NOT_THROW
)
3991 bitmap_set_bit (r_reachable
, region
->index
);
3994 && !bitmap_bit_p (r_reachable
, region
->index
))
3996 "Removing unreachable region %d\n",
4000 remove_unreachable_eh_regions (r_reachable
);
4002 sbitmap_free (r_reachable
);
4005 /* Undo critical edge splitting on an EH landing pad. Earlier, we
4006 optimisticaly split all sorts of edges, including EH edges. The
4007 optimization passes in between may not have needed them; if not,
4008 we should undo the split.
4010 Recognize this case by having one EH edge incoming to the BB and
4011 one normal edge outgoing; BB should be empty apart from the
4012 post_landing_pad label.
4014 Note that this is slightly different from the empty handler case
4015 handled by cleanup_empty_eh, in that the actual handler may yet
4016 have actual code but the landing pad has been separated from the
4017 handler. As such, cleanup_empty_eh relies on this transformation
4018 having been done first. */
4021 unsplit_eh (eh_landing_pad lp
)
4023 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4024 gimple_stmt_iterator gsi
;
4027 /* Quickly check the edge counts on BB for singularity. */
4028 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4030 e_in
= single_pred_edge (bb
);
4031 e_out
= single_succ_edge (bb
);
4033 /* Input edge must be EH and output edge must be normal. */
4034 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4037 /* The block must be empty except for the labels and debug insns. */
4038 gsi
= gsi_after_labels (bb
);
4039 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4040 gsi_next_nondebug (&gsi
);
4041 if (!gsi_end_p (gsi
))
4044 /* The destination block must not already have a landing pad
4045 for a different region. */
4046 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4048 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4054 lab
= gimple_label_label (label_stmt
);
4055 lp_nr
= EH_LANDING_PAD_NR (lab
);
4056 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4060 /* The new destination block must not already be a destination of
4061 the source block, lest we merge fallthru and eh edges and get
4062 all sorts of confused. */
4063 if (find_edge (e_in
->src
, e_out
->dest
))
4066 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4067 thought this should have been cleaned up by a phicprop pass, but
4068 that doesn't appear to handle virtuals. Propagate by hand. */
4069 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4071 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4074 gphi
*phi
= gpi
.phi ();
4075 tree lhs
= gimple_phi_result (phi
);
4076 tree rhs
= gimple_phi_arg_def (phi
, 0);
4077 use_operand_p use_p
;
4078 imm_use_iterator iter
;
4080 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4082 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4083 SET_USE (use_p
, rhs
);
4086 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4087 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4089 remove_phi_node (&gpi
, true);
4093 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4094 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4095 lp
->index
, e_out
->dest
->index
);
4097 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4098 a successor edge, humor it. But do the real CFG change with the
4099 predecessor of E_OUT in order to preserve the ordering of arguments
4100 to the PHI nodes in E_OUT->DEST. */
4101 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4102 redirect_edge_pred (e_out
, e_in
->src
);
4103 e_out
->flags
= e_in
->flags
;
4104 e_out
->probability
= e_in
->probability
;
4105 e_out
->count
= e_in
->count
;
4111 /* Examine each landing pad block and see if it matches unsplit_eh. */
4114 unsplit_all_eh (void)
4116 bool changed
= false;
4120 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4122 changed
|= unsplit_eh (lp
);
4127 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4128 to OLD_BB to NEW_BB; return true on success, false on failure.
4130 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4131 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4132 Virtual PHIs may be deleted and marked for renaming. */
4135 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4136 edge old_bb_out
, bool change_region
)
4138 gphi_iterator ngsi
, ogsi
;
4141 bitmap ophi_handled
;
4143 /* The destination block must not be a regular successor for any
4144 of the preds of the landing pad. Thus, avoid turning
4154 which CFG verification would choke on. See PR45172 and PR51089. */
4155 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4156 if (find_edge (e
->src
, new_bb
))
4159 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4160 redirect_edge_var_map_clear (e
);
4162 ophi_handled
= BITMAP_ALLOC (NULL
);
4164 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4165 for the edges we're going to move. */
4166 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4168 gphi
*ophi
, *nphi
= ngsi
.phi ();
4171 nresult
= gimple_phi_result (nphi
);
4172 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4174 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4175 the source ssa_name. */
4177 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4180 if (gimple_phi_result (ophi
) == nop
)
4185 /* If we did find the corresponding PHI, copy those inputs. */
4188 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4189 if (!has_single_use (nop
))
4191 imm_use_iterator imm_iter
;
4192 use_operand_p use_p
;
4194 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4196 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4197 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4198 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4202 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4203 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4208 if ((e
->flags
& EDGE_EH
) == 0)
4210 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4211 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4212 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4215 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4216 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4217 variable is unchanged from input to the block and we can simply
4218 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4222 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4223 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4224 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4228 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4229 we don't know what values from the other edges into NEW_BB to use. */
4230 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4232 gphi
*ophi
= ogsi
.phi ();
4233 tree oresult
= gimple_phi_result (ophi
);
4234 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4238 /* Finally, move the edges and update the PHIs. */
4239 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4240 if (e
->flags
& EDGE_EH
)
4242 /* ??? CFG manipluation routines do not try to update loop
4243 form on edge redirection. Do so manually here for now. */
4244 /* If we redirect a loop entry or latch edge that will either create
4245 a multiple entry loop or rotate the loop. If the loops merge
4246 we may have created a loop with multiple latches.
4247 All of this isn't easily fixed thus cancel the affected loop
4248 and mark the other loop as possibly having multiple latches. */
4249 if (e
->dest
== e
->dest
->loop_father
->header
)
4251 mark_loop_for_removal (e
->dest
->loop_father
);
4252 new_bb
->loop_father
->latch
= NULL
;
4253 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4255 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4256 redirect_edge_succ (e
, new_bb
);
4257 flush_pending_stmts (e
);
4262 BITMAP_FREE (ophi_handled
);
4266 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4267 redirect_edge_var_map_clear (e
);
4268 BITMAP_FREE (ophi_handled
);
4272 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4273 old region to NEW_REGION at BB. */
4276 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4277 eh_landing_pad lp
, eh_region new_region
)
4279 gimple_stmt_iterator gsi
;
4282 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4286 lp
->region
= new_region
;
4287 lp
->next_lp
= new_region
->landing_pads
;
4288 new_region
->landing_pads
= lp
;
4290 /* Delete the RESX that was matched within the empty handler block. */
4291 gsi
= gsi_last_bb (bb
);
4292 unlink_stmt_vdef (gsi_stmt (gsi
));
4293 gsi_remove (&gsi
, true);
4295 /* Clean up E_OUT for the fallthru. */
4296 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4297 e_out
->probability
= profile_probability::always ();
4298 e_out
->count
= e_out
->src
->count
;
4301 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4302 unsplitting than unsplit_eh was prepared to handle, e.g. when
4303 multiple incoming edges and phis are involved. */
4306 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4308 gimple_stmt_iterator gsi
;
4311 /* We really ought not have totally lost everything following
4312 a landing pad label. Given that BB is empty, there had better
4314 gcc_assert (e_out
!= NULL
);
4316 /* The destination block must not already have a landing pad
4317 for a different region. */
4319 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4321 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4326 lab
= gimple_label_label (stmt
);
4327 lp_nr
= EH_LANDING_PAD_NR (lab
);
4328 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4332 /* Attempt to move the PHIs into the successor block. */
4333 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4335 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4337 "Unsplit EH landing pad %d to block %i "
4338 "(via cleanup_empty_eh).\n",
4339 lp
->index
, e_out
->dest
->index
);
4346 /* Return true if edge E_FIRST is part of an empty infinite loop
4347 or leads to such a loop through a series of single successor
4351 infinite_empty_loop_p (edge e_first
)
4353 bool inf_loop
= false;
4356 if (e_first
->dest
== e_first
->src
)
4359 e_first
->src
->aux
= (void *) 1;
4360 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4362 gimple_stmt_iterator gsi
;
4368 e
->dest
->aux
= (void *) 1;
4369 gsi
= gsi_after_labels (e
->dest
);
4370 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4371 gsi_next_nondebug (&gsi
);
4372 if (!gsi_end_p (gsi
))
4375 e_first
->src
->aux
= NULL
;
4376 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4377 e
->dest
->aux
= NULL
;
4382 /* Examine the block associated with LP to determine if it's an empty
4383 handler for its EH region. If so, attempt to redirect EH edges to
4384 an outer region. Return true the CFG was updated in any way. This
4385 is similar to jump forwarding, just across EH edges. */
4388 cleanup_empty_eh (eh_landing_pad lp
)
4390 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4391 gimple_stmt_iterator gsi
;
4393 eh_region new_region
;
4396 bool has_non_eh_pred
;
4400 /* There can be zero or one edges out of BB. This is the quickest test. */
4401 switch (EDGE_COUNT (bb
->succs
))
4407 e_out
= single_succ_edge (bb
);
4413 gsi
= gsi_last_nondebug_bb (bb
);
4414 resx
= gsi_stmt (gsi
);
4415 if (resx
&& is_gimple_resx (resx
))
4417 if (stmt_can_throw_external (resx
))
4418 optimize_clobbers (bb
);
4419 else if (sink_clobbers (bb
))
4423 gsi
= gsi_after_labels (bb
);
4425 /* Make sure to skip debug statements. */
4426 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4427 gsi_next_nondebug (&gsi
);
4429 /* If the block is totally empty, look for more unsplitting cases. */
4430 if (gsi_end_p (gsi
))
4432 /* For the degenerate case of an infinite loop bail out.
4433 If bb has no successors and is totally empty, which can happen e.g.
4434 because of incorrect noreturn attribute, bail out too. */
4436 || infinite_empty_loop_p (e_out
))
4439 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4442 /* The block should consist only of a single RESX statement, modulo a
4443 preceding call to __builtin_stack_restore if there is no outgoing
4444 edge, since the call can be eliminated in this case. */
4445 resx
= gsi_stmt (gsi
);
4446 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4448 gsi_next_nondebug (&gsi
);
4449 resx
= gsi_stmt (gsi
);
4451 if (!is_gimple_resx (resx
))
4453 gcc_assert (gsi_one_nondebug_before_end_p (gsi
));
4455 /* Determine if there are non-EH edges, or resx edges into the handler. */
4456 has_non_eh_pred
= false;
4457 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4458 if (!(e
->flags
& EDGE_EH
))
4459 has_non_eh_pred
= true;
4461 /* Find the handler that's outer of the empty handler by looking at
4462 where the RESX instruction was vectored. */
4463 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4464 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4466 /* If there's no destination region within the current function,
4467 redirection is trivial via removing the throwing statements from
4468 the EH region, removing the EH edges, and allowing the block
4469 to go unreachable. */
4470 if (new_region
== NULL
)
4472 gcc_assert (e_out
== NULL
);
4473 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4474 if (e
->flags
& EDGE_EH
)
4476 gimple
*stmt
= last_stmt (e
->src
);
4477 remove_stmt_from_eh_lp (stmt
);
4485 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4486 to handle the abort and allow the blocks to go unreachable. */
4487 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4489 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4490 if (e
->flags
& EDGE_EH
)
4492 gimple
*stmt
= last_stmt (e
->src
);
4493 remove_stmt_from_eh_lp (stmt
);
4494 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4502 /* Try to redirect the EH edges and merge the PHIs into the destination
4503 landing pad block. If the merge succeeds, we'll already have redirected
4504 all the EH edges. The handler itself will go unreachable if there were
4506 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4509 /* Finally, if all input edges are EH edges, then we can (potentially)
4510 reduce the number of transfers from the runtime by moving the landing
4511 pad from the original region to the new region. This is a win when
4512 we remove the last CLEANUP region along a particular exception
4513 propagation path. Since nothing changes except for the region with
4514 which the landing pad is associated, the PHI nodes do not need to be
4516 if (!has_non_eh_pred
)
4518 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4519 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4520 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4521 lp
->index
, new_region
->index
);
4523 /* ??? The CFG didn't change, but we may have rendered the
4524 old EH region unreachable. Trigger a cleanup there. */
4531 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4532 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4533 remove_eh_landing_pad (lp
);
4537 /* Do a post-order traversal of the EH region tree. Examine each
4538 post_landing_pad block and see if we can eliminate it as empty. */
4541 cleanup_all_empty_eh (void)
4543 bool changed
= false;
4547 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4549 changed
|= cleanup_empty_eh (lp
);
4554 /* Perform cleanups and lowering of exception handling
4555 1) cleanups regions with handlers doing nothing are optimized out
4556 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4557 3) Info about regions that are containing instructions, and regions
4558 reachable via local EH edges is collected
4559 4) Eh tree is pruned for regions no longer necessary.
4561 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4562 Unify those that have the same failure decl and locus.
4566 execute_cleanup_eh_1 (void)
4568 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4569 looking up unreachable landing pads. */
4570 remove_unreachable_handlers ();
4572 /* Watch out for the region tree vanishing due to all unreachable. */
4573 if (cfun
->eh
->region_tree
)
4575 bool changed
= false;
4578 changed
|= unsplit_all_eh ();
4579 changed
|= cleanup_all_empty_eh ();
4583 free_dominance_info (CDI_DOMINATORS
);
4584 free_dominance_info (CDI_POST_DOMINATORS
);
4586 /* We delayed all basic block deletion, as we may have performed
4587 cleanups on EH edges while non-EH edges were still present. */
4588 delete_unreachable_blocks ();
4590 /* We manipulated the landing pads. Remove any region that no
4591 longer has a landing pad. */
4592 remove_unreachable_handlers_no_lp ();
4594 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4603 const pass_data pass_data_cleanup_eh
=
4605 GIMPLE_PASS
, /* type */
4606 "ehcleanup", /* name */
4607 OPTGROUP_NONE
, /* optinfo_flags */
4608 TV_TREE_EH
, /* tv_id */
4609 PROP_gimple_lcf
, /* properties_required */
4610 0, /* properties_provided */
4611 0, /* properties_destroyed */
4612 0, /* todo_flags_start */
4613 0, /* todo_flags_finish */
4616 class pass_cleanup_eh
: public gimple_opt_pass
4619 pass_cleanup_eh (gcc::context
*ctxt
)
4620 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4623 /* opt_pass methods: */
4624 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4625 virtual bool gate (function
*fun
)
4627 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4630 virtual unsigned int execute (function
*);
4632 }; // class pass_cleanup_eh
4635 pass_cleanup_eh::execute (function
*fun
)
4637 int ret
= execute_cleanup_eh_1 ();
4639 /* If the function no longer needs an EH personality routine
4640 clear it. This exposes cross-language inlining opportunities
4641 and avoids references to a never defined personality routine. */
4642 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4643 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4644 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4652 make_pass_cleanup_eh (gcc::context
*ctxt
)
4654 return new pass_cleanup_eh (ctxt
);
4657 /* Verify that BB containing STMT as the last statement, has precisely the
4658 edge that make_eh_edges would create. */
4661 verify_eh_edges (gimple
*stmt
)
4663 basic_block bb
= gimple_bb (stmt
);
4664 eh_landing_pad lp
= NULL
;
4669 lp_nr
= lookup_stmt_eh_lp (stmt
);
4671 lp
= get_eh_landing_pad_from_number (lp_nr
);
4674 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4676 if (e
->flags
& EDGE_EH
)
4680 error ("BB %i has multiple EH edges", bb
->index
);
4692 error ("BB %i can not throw but has an EH edge", bb
->index
);
4698 if (!stmt_could_throw_p (stmt
))
4700 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4704 if (eh_edge
== NULL
)
4706 error ("BB %i is missing an EH edge", bb
->index
);
4710 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4712 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4719 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4722 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4726 basic_block src
, dst
;
4727 bool want_fallthru
= true;
4731 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4732 src
= gimple_bb (stmt
);
4734 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4735 gcc_assert (e
->aux
== NULL
);
4740 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4742 dst
= label_to_block (c
->label
);
4743 e
= find_edge (src
, dst
);
4746 error ("BB %i is missing an edge", src
->index
);
4751 /* A catch-all handler doesn't have a fallthru. */
4752 if (c
->type_list
== NULL
)
4754 want_fallthru
= false;
4760 case ERT_ALLOWED_EXCEPTIONS
:
4761 dst
= label_to_block (r
->u
.allowed
.label
);
4762 e
= find_edge (src
, dst
);
4765 error ("BB %i is missing an edge", src
->index
);
4776 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4778 if (e
->flags
& EDGE_FALLTHRU
)
4780 if (fall_edge
!= NULL
)
4782 error ("BB %i too many fallthru edges", src
->index
);
4791 error ("BB %i has incorrect edge", src
->index
);
4795 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4797 error ("BB %i has incorrect fallthru edge", src
->index
);