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"
47 /* In some instances a tree and a gimple need to be stored in a same table,
48 i.e. in hash tables. This is a structure to do this. */
49 typedef union {tree
*tp
; tree t
; gimple
*g
;} treemple
;
51 /* Misc functions used in this file. */
53 /* Remember and lookup EH landing pad data for arbitrary statements.
54 Really this means any statement that could_throw_p. We could
55 stuff this information into the stmt_ann data structure, but:
57 (1) We absolutely rely on this information being kept until
58 we get to rtl. Once we're done with lowering here, if we lose
59 the information there's no way to recover it!
61 (2) There are many more statements that *cannot* throw as
62 compared to those that can. We should be saving some amount
63 of space by only allocating memory for those that can throw. */
65 /* Add statement T in function IFUN to landing pad NUM. */
68 add_stmt_to_eh_lp_fn (struct function
*ifun
, gimple
*t
, int num
)
70 gcc_assert (num
!= 0);
72 if (!get_eh_throw_stmt_table (ifun
))
73 set_eh_throw_stmt_table (ifun
, hash_map
<gimple
*, int>::create_ggc (31));
75 gcc_assert (!get_eh_throw_stmt_table (ifun
)->put (t
, num
));
78 /* Add statement T in the current function (cfun) to EH landing pad NUM. */
81 add_stmt_to_eh_lp (gimple
*t
, int num
)
83 add_stmt_to_eh_lp_fn (cfun
, t
, num
);
86 /* Add statement T to the single EH landing pad in REGION. */
89 record_stmt_eh_region (eh_region region
, gimple
*t
)
93 if (region
->type
== ERT_MUST_NOT_THROW
)
94 add_stmt_to_eh_lp_fn (cfun
, t
, -region
->index
);
97 eh_landing_pad lp
= region
->landing_pads
;
99 lp
= gen_eh_landing_pad (region
);
101 gcc_assert (lp
->next_lp
== NULL
);
102 add_stmt_to_eh_lp_fn (cfun
, t
, lp
->index
);
107 /* Remove statement T in function IFUN from its EH landing pad. */
110 remove_stmt_from_eh_lp_fn (struct function
*ifun
, gimple
*t
)
112 if (!get_eh_throw_stmt_table (ifun
))
115 if (!get_eh_throw_stmt_table (ifun
)->get (t
))
118 get_eh_throw_stmt_table (ifun
)->remove (t
);
123 /* Remove statement T in the current function (cfun) from its
127 remove_stmt_from_eh_lp (gimple
*t
)
129 return remove_stmt_from_eh_lp_fn (cfun
, t
);
132 /* Determine if statement T is inside an EH region in function IFUN.
133 Positive numbers indicate a landing pad index; negative numbers
134 indicate a MUST_NOT_THROW region index; zero indicates that the
135 statement is not recorded in the region table. */
138 lookup_stmt_eh_lp_fn (struct function
*ifun
, gimple
*t
)
140 if (ifun
->eh
->throw_stmt_table
== NULL
)
143 int *lp_nr
= ifun
->eh
->throw_stmt_table
->get (t
);
144 return lp_nr
? *lp_nr
: 0;
147 /* Likewise, but always use the current function. */
150 lookup_stmt_eh_lp (gimple
*t
)
152 /* We can get called from initialized data when -fnon-call-exceptions
153 is on; prevent crash. */
156 return lookup_stmt_eh_lp_fn (cfun
, t
);
159 /* First pass of EH node decomposition. Build up a tree of GIMPLE_TRY_FINALLY
160 nodes and LABEL_DECL nodes. We will use this during the second phase to
161 determine if a goto leaves the body of a TRY_FINALLY_EXPR node. */
163 struct finally_tree_node
165 /* When storing a GIMPLE_TRY, we have to record a gimple. However
166 when deciding whether a GOTO to a certain LABEL_DECL (which is a
167 tree) leaves the TRY block, its necessary to record a tree in
168 this field. Thus a treemple is used. */
173 /* Hashtable helpers. */
175 struct finally_tree_hasher
: free_ptr_hash
<finally_tree_node
>
177 static inline hashval_t
hash (const finally_tree_node
*);
178 static inline bool equal (const finally_tree_node
*,
179 const finally_tree_node
*);
183 finally_tree_hasher::hash (const finally_tree_node
*v
)
185 return (intptr_t)v
->child
.t
>> 4;
189 finally_tree_hasher::equal (const finally_tree_node
*v
,
190 const finally_tree_node
*c
)
192 return v
->child
.t
== c
->child
.t
;
195 /* Note that this table is *not* marked GTY. It is short-lived. */
196 static hash_table
<finally_tree_hasher
> *finally_tree
;
199 record_in_finally_tree (treemple child
, gtry
*parent
)
201 struct finally_tree_node
*n
;
202 finally_tree_node
**slot
;
204 n
= XNEW (struct finally_tree_node
);
208 slot
= finally_tree
->find_slot (n
, INSERT
);
214 collect_finally_tree (gimple
*stmt
, gtry
*region
);
216 /* Go through the gimple sequence. Works with collect_finally_tree to
217 record all GIMPLE_LABEL and GIMPLE_TRY statements. */
220 collect_finally_tree_1 (gimple_seq seq
, gtry
*region
)
222 gimple_stmt_iterator gsi
;
224 for (gsi
= gsi_start (seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
225 collect_finally_tree (gsi_stmt (gsi
), region
);
229 collect_finally_tree (gimple
*stmt
, gtry
*region
)
233 switch (gimple_code (stmt
))
236 temp
.t
= gimple_label_label (as_a
<glabel
*> (stmt
));
237 record_in_finally_tree (temp
, region
);
241 if (gimple_try_kind (stmt
) == GIMPLE_TRY_FINALLY
)
244 record_in_finally_tree (temp
, region
);
245 collect_finally_tree_1 (gimple_try_eval (stmt
),
246 as_a
<gtry
*> (stmt
));
247 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
249 else if (gimple_try_kind (stmt
) == GIMPLE_TRY_CATCH
)
251 collect_finally_tree_1 (gimple_try_eval (stmt
), region
);
252 collect_finally_tree_1 (gimple_try_cleanup (stmt
), region
);
257 collect_finally_tree_1 (gimple_catch_handler (
258 as_a
<gcatch
*> (stmt
)),
262 case GIMPLE_EH_FILTER
:
263 collect_finally_tree_1 (gimple_eh_filter_failure (stmt
), region
);
268 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
269 collect_finally_tree_1 (gimple_eh_else_n_body (eh_else_stmt
), region
);
270 collect_finally_tree_1 (gimple_eh_else_e_body (eh_else_stmt
), region
);
275 /* A type, a decl, or some kind of statement that we're not
276 interested in. Don't walk them. */
282 /* Use the finally tree to determine if a jump from START to TARGET
283 would leave the try_finally node that START lives in. */
286 outside_finally_tree (treemple start
, gimple
*target
)
288 struct finally_tree_node n
, *p
;
293 p
= finally_tree
->find (&n
);
298 while (start
.g
!= target
);
303 /* Second pass of EH node decomposition. Actually transform the GIMPLE_TRY
304 nodes into a set of gotos, magic labels, and eh regions.
305 The eh region creation is straight-forward, but frobbing all the gotos
306 and such into shape isn't. */
308 /* The sequence into which we record all EH stuff. This will be
309 placed at the end of the function when we're all done. */
310 static gimple_seq eh_seq
;
312 /* Record whether an EH region contains something that can throw,
313 indexed by EH region number. */
314 static bitmap eh_region_may_contain_throw_map
;
316 /* The GOTO_QUEUE is an array of GIMPLE_GOTO and GIMPLE_RETURN
317 statements that are seen to escape this GIMPLE_TRY_FINALLY node.
318 The idea is to record a gimple statement for everything except for
319 the conditionals, which get their labels recorded. Since labels are
320 of type 'tree', we need this node to store both gimple and tree
321 objects. REPL_STMT is the sequence used to replace the goto/return
322 statement. CONT_STMT is used to store the statement that allows
323 the return/goto to jump to the original destination. */
325 struct goto_queue_node
329 gimple_seq repl_stmt
;
332 /* This is used when index >= 0 to indicate that stmt is a label (as
333 opposed to a goto stmt). */
337 /* State of the world while lowering. */
341 /* What's "current" while constructing the eh region tree. These
342 correspond to variables of the same name in cfun->eh, which we
343 don't have easy access to. */
344 eh_region cur_region
;
346 /* What's "current" for the purposes of __builtin_eh_pointer. For
347 a CATCH, this is the associated TRY. For an EH_FILTER, this is
348 the associated ALLOWED_EXCEPTIONS, etc. */
349 eh_region ehp_region
;
351 /* Processing of TRY_FINALLY requires a bit more state. This is
352 split out into a separate structure so that we don't have to
353 copy so much when processing other nodes. */
354 struct leh_tf_state
*tf
;
359 /* Pointer to the GIMPLE_TRY_FINALLY node under discussion. The
360 try_finally_expr is the original GIMPLE_TRY_FINALLY. We need to retain
361 this so that outside_finally_tree can reliably reference the tree used
362 in the collect_finally_tree data structures. */
363 gtry
*try_finally_expr
;
366 /* While lowering a top_p usually it is expanded into multiple statements,
367 thus we need the following field to store them. */
368 gimple_seq top_p_seq
;
370 /* The state outside this try_finally node. */
371 struct leh_state
*outer
;
373 /* The exception region created for it. */
376 /* The goto queue. */
377 struct goto_queue_node
*goto_queue
;
378 size_t goto_queue_size
;
379 size_t goto_queue_active
;
381 /* Pointer map to help in searching goto_queue when it is large. */
382 hash_map
<gimple
*, goto_queue_node
*> *goto_queue_map
;
384 /* The set of unique labels seen as entries in the goto queue. */
385 vec
<tree
> dest_array
;
387 /* A label to be added at the end of the completed transformed
388 sequence. It will be set if may_fallthru was true *at one time*,
389 though subsequent transformations may have cleared that flag. */
392 /* True if it is possible to fall out the bottom of the try block.
393 Cleared if the fallthru is converted to a goto. */
396 /* True if any entry in goto_queue is a GIMPLE_RETURN. */
399 /* True if the finally block can receive an exception edge.
400 Cleared if the exception case is handled by code duplication. */
404 static gimple_seq
lower_eh_must_not_throw (struct leh_state
*, gtry
*);
406 /* Search for STMT in the goto queue. Return the replacement,
407 or null if the statement isn't in the queue. */
409 #define LARGE_GOTO_QUEUE 20
411 static void lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*seq
);
414 find_goto_replacement (struct leh_tf_state
*tf
, treemple stmt
)
418 if (tf
->goto_queue_active
< LARGE_GOTO_QUEUE
)
420 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
421 if ( tf
->goto_queue
[i
].stmt
.g
== stmt
.g
)
422 return tf
->goto_queue
[i
].repl_stmt
;
426 /* If we have a large number of entries in the goto_queue, create a
427 pointer map and use that for searching. */
429 if (!tf
->goto_queue_map
)
431 tf
->goto_queue_map
= new hash_map
<gimple
*, goto_queue_node
*>;
432 for (i
= 0; i
< tf
->goto_queue_active
; i
++)
434 bool existed
= tf
->goto_queue_map
->put (tf
->goto_queue
[i
].stmt
.g
,
436 gcc_assert (!existed
);
440 goto_queue_node
**slot
= tf
->goto_queue_map
->get (stmt
.g
);
442 return ((*slot
)->repl_stmt
);
447 /* A subroutine of replace_goto_queue_1. Handles the sub-clauses of a
448 lowered GIMPLE_COND. If, by chance, the replacement is a simple goto,
449 then we can just splat it in, otherwise we add the new stmts immediately
450 after the GIMPLE_COND and redirect. */
453 replace_goto_queue_cond_clause (tree
*tp
, struct leh_tf_state
*tf
,
454 gimple_stmt_iterator
*gsi
)
459 location_t loc
= gimple_location (gsi_stmt (*gsi
));
462 new_seq
= find_goto_replacement (tf
, temp
);
466 if (gimple_seq_singleton_p (new_seq
)
467 && gimple_code (gimple_seq_first_stmt (new_seq
)) == GIMPLE_GOTO
)
469 *tp
= gimple_goto_dest (gimple_seq_first_stmt (new_seq
));
473 label
= create_artificial_label (loc
);
474 /* Set the new label for the GIMPLE_COND */
477 gsi_insert_after (gsi
, gimple_build_label (label
), GSI_CONTINUE_LINKING
);
478 gsi_insert_seq_after (gsi
, gimple_seq_copy (new_seq
), GSI_CONTINUE_LINKING
);
481 /* The real work of replace_goto_queue. Returns with TSI updated to
482 point to the next statement. */
484 static void replace_goto_queue_stmt_list (gimple_seq
*, struct leh_tf_state
*);
487 replace_goto_queue_1 (gimple
*stmt
, struct leh_tf_state
*tf
,
488 gimple_stmt_iterator
*gsi
)
494 switch (gimple_code (stmt
))
499 seq
= find_goto_replacement (tf
, temp
);
502 gsi_insert_seq_before (gsi
, gimple_seq_copy (seq
), GSI_SAME_STMT
);
503 gsi_remove (gsi
, false);
509 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 2), tf
, gsi
);
510 replace_goto_queue_cond_clause (gimple_op_ptr (stmt
, 3), tf
, gsi
);
514 replace_goto_queue_stmt_list (gimple_try_eval_ptr (stmt
), tf
);
515 replace_goto_queue_stmt_list (gimple_try_cleanup_ptr (stmt
), tf
);
518 replace_goto_queue_stmt_list (gimple_catch_handler_ptr (
519 as_a
<gcatch
*> (stmt
)),
522 case GIMPLE_EH_FILTER
:
523 replace_goto_queue_stmt_list (gimple_eh_filter_failure_ptr (stmt
), tf
);
527 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (stmt
);
528 replace_goto_queue_stmt_list (gimple_eh_else_n_body_ptr (eh_else_stmt
),
530 replace_goto_queue_stmt_list (gimple_eh_else_e_body_ptr (eh_else_stmt
),
536 /* These won't have gotos in them. */
543 /* A subroutine of replace_goto_queue. Handles GIMPLE_SEQ. */
546 replace_goto_queue_stmt_list (gimple_seq
*seq
, struct leh_tf_state
*tf
)
548 gimple_stmt_iterator gsi
= gsi_start (*seq
);
550 while (!gsi_end_p (gsi
))
551 replace_goto_queue_1 (gsi_stmt (gsi
), tf
, &gsi
);
554 /* Replace all goto queue members. */
557 replace_goto_queue (struct leh_tf_state
*tf
)
559 if (tf
->goto_queue_active
== 0)
561 replace_goto_queue_stmt_list (&tf
->top_p_seq
, tf
);
562 replace_goto_queue_stmt_list (&eh_seq
, tf
);
565 /* Add a new record to the goto queue contained in TF. NEW_STMT is the
566 data to be added, IS_LABEL indicates whether NEW_STMT is a label or
570 record_in_goto_queue (struct leh_tf_state
*tf
,
577 struct goto_queue_node
*q
;
579 gcc_assert (!tf
->goto_queue_map
);
581 active
= tf
->goto_queue_active
;
582 size
= tf
->goto_queue_size
;
585 size
= (size
? size
* 2 : 32);
586 tf
->goto_queue_size
= size
;
588 = XRESIZEVEC (struct goto_queue_node
, tf
->goto_queue
, size
);
591 q
= &tf
->goto_queue
[active
];
592 tf
->goto_queue_active
= active
+ 1;
594 memset (q
, 0, sizeof (*q
));
597 q
->location
= location
;
598 q
->is_label
= is_label
;
601 /* Record the LABEL label in the goto queue contained in TF.
605 record_in_goto_queue_label (struct leh_tf_state
*tf
, treemple stmt
, tree label
,
609 treemple temp
, new_stmt
;
614 /* Computed and non-local gotos do not get processed. Given
615 their nature we can neither tell whether we've escaped the
616 finally block nor redirect them if we knew. */
617 if (TREE_CODE (label
) != LABEL_DECL
)
620 /* No need to record gotos that don't leave the try block. */
622 if (!outside_finally_tree (temp
, tf
->try_finally_expr
))
625 if (! tf
->dest_array
.exists ())
627 tf
->dest_array
.create (10);
628 tf
->dest_array
.quick_push (label
);
633 int n
= tf
->dest_array
.length ();
634 for (index
= 0; index
< n
; ++index
)
635 if (tf
->dest_array
[index
] == label
)
638 tf
->dest_array
.safe_push (label
);
641 /* In the case of a GOTO we want to record the destination label,
642 since with a GIMPLE_COND we have an easy access to the then/else
645 record_in_goto_queue (tf
, new_stmt
, index
, true, location
);
648 /* For any GIMPLE_GOTO or GIMPLE_RETURN, decide whether it leaves a try_finally
649 node, and if so record that fact in the goto queue associated with that
653 maybe_record_in_goto_queue (struct leh_state
*state
, gimple
*stmt
)
655 struct leh_tf_state
*tf
= state
->tf
;
661 switch (gimple_code (stmt
))
665 gcond
*cond_stmt
= as_a
<gcond
*> (stmt
);
666 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 2);
667 record_in_goto_queue_label (tf
, new_stmt
,
668 gimple_cond_true_label (cond_stmt
),
669 EXPR_LOCATION (*new_stmt
.tp
));
670 new_stmt
.tp
= gimple_op_ptr (cond_stmt
, 3);
671 record_in_goto_queue_label (tf
, new_stmt
,
672 gimple_cond_false_label (cond_stmt
),
673 EXPR_LOCATION (*new_stmt
.tp
));
678 record_in_goto_queue_label (tf
, new_stmt
, gimple_goto_dest (stmt
),
679 gimple_location (stmt
));
683 tf
->may_return
= true;
685 record_in_goto_queue (tf
, new_stmt
, -1, false, gimple_location (stmt
));
695 /* We do not process GIMPLE_SWITCHes for now. As long as the original source
696 was in fact structured, and we've not yet done jump threading, then none
697 of the labels will leave outer GIMPLE_TRY_FINALLY nodes. Verify this. */
700 verify_norecord_switch_expr (struct leh_state
*state
,
701 gswitch
*switch_expr
)
703 struct leh_tf_state
*tf
= state
->tf
;
709 n
= gimple_switch_num_labels (switch_expr
);
711 for (i
= 0; i
< n
; ++i
)
714 tree lab
= CASE_LABEL (gimple_switch_label (switch_expr
, i
));
716 gcc_assert (!outside_finally_tree (temp
, tf
->try_finally_expr
));
720 #define verify_norecord_switch_expr(state, switch_expr)
723 /* Redirect a RETURN_EXPR pointed to by Q to FINLAB. If MOD is
724 non-null, insert it before the new branch. */
727 do_return_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
)
731 /* In the case of a return, the queue node must be a gimple statement. */
732 gcc_assert (!q
->is_label
);
734 /* Note that the return value may have already been computed, e.g.,
747 should return 0, not 1. We don't have to do anything to make
748 this happens because the return value has been placed in the
749 RESULT_DECL already. */
751 q
->cont_stmt
= q
->stmt
.g
;
754 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
756 x
= gimple_build_goto (finlab
);
757 gimple_set_location (x
, q
->location
);
758 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
761 /* Similar, but easier, for GIMPLE_GOTO. */
764 do_goto_redirection (struct goto_queue_node
*q
, tree finlab
, gimple_seq mod
,
765 struct leh_tf_state
*tf
)
769 gcc_assert (q
->is_label
);
771 q
->cont_stmt
= gimple_build_goto (tf
->dest_array
[q
->index
]);
774 gimple_seq_add_seq (&q
->repl_stmt
, mod
);
776 x
= gimple_build_goto (finlab
);
777 gimple_set_location (x
, q
->location
);
778 gimple_seq_add_stmt (&q
->repl_stmt
, x
);
781 /* Emit a standard landing pad sequence into SEQ for REGION. */
784 emit_post_landing_pad (gimple_seq
*seq
, eh_region region
)
786 eh_landing_pad lp
= region
->landing_pads
;
790 lp
= gen_eh_landing_pad (region
);
792 lp
->post_landing_pad
= create_artificial_label (UNKNOWN_LOCATION
);
793 EH_LANDING_PAD_NR (lp
->post_landing_pad
) = lp
->index
;
795 x
= gimple_build_label (lp
->post_landing_pad
);
796 gimple_seq_add_stmt (seq
, x
);
799 /* Emit a RESX statement into SEQ for REGION. */
802 emit_resx (gimple_seq
*seq
, eh_region region
)
804 gresx
*x
= gimple_build_resx (region
->index
);
805 gimple_seq_add_stmt (seq
, x
);
807 record_stmt_eh_region (region
->outer
, x
);
810 /* Emit an EH_DISPATCH statement into SEQ for REGION. */
813 emit_eh_dispatch (gimple_seq
*seq
, eh_region region
)
815 geh_dispatch
*x
= gimple_build_eh_dispatch (region
->index
);
816 gimple_seq_add_stmt (seq
, x
);
819 /* Note that the current EH region may contain a throw, or a
820 call to a function which itself may contain a throw. */
823 note_eh_region_may_contain_throw (eh_region region
)
825 while (bitmap_set_bit (eh_region_may_contain_throw_map
, region
->index
))
827 if (region
->type
== ERT_MUST_NOT_THROW
)
829 region
= region
->outer
;
835 /* Check if REGION has been marked as containing a throw. If REGION is
836 NULL, this predicate is false. */
839 eh_region_may_contain_throw (eh_region r
)
841 return r
&& bitmap_bit_p (eh_region_may_contain_throw_map
, r
->index
);
844 /* We want to transform
845 try { body; } catch { stuff; }
855 TP is a GIMPLE_TRY node. REGION is the region whose post_landing_pad
856 should be placed before the second operand, or NULL. OVER is
857 an existing label that should be put at the exit, or NULL. */
860 frob_into_branch_around (gtry
*tp
, eh_region region
, tree over
)
863 gimple_seq cleanup
, result
;
864 location_t loc
= gimple_location (tp
);
866 cleanup
= gimple_try_cleanup (tp
);
867 result
= gimple_try_eval (tp
);
870 emit_post_landing_pad (&eh_seq
, region
);
872 if (gimple_seq_may_fallthru (cleanup
))
875 over
= create_artificial_label (loc
);
876 x
= gimple_build_goto (over
);
877 gimple_set_location (x
, loc
);
878 gimple_seq_add_stmt (&cleanup
, x
);
880 gimple_seq_add_seq (&eh_seq
, cleanup
);
884 x
= gimple_build_label (over
);
885 gimple_seq_add_stmt (&result
, x
);
890 /* A subroutine of lower_try_finally. Duplicate the tree rooted at T.
891 Make sure to record all new labels found. */
894 lower_try_finally_dup_block (gimple_seq seq
, struct leh_state
*outer_state
,
899 gimple_stmt_iterator gsi
;
901 new_seq
= copy_gimple_seq_and_replace_locals (seq
);
903 for (gsi
= gsi_start (new_seq
); !gsi_end_p (gsi
); gsi_next (&gsi
))
905 gimple
*stmt
= gsi_stmt (gsi
);
906 /* We duplicate __builtin_stack_restore at -O0 in the hope of eliminating
907 it on the EH paths. When it is not eliminated, make it transparent in
909 if (gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
910 gimple_set_location (stmt
, UNKNOWN_LOCATION
);
911 else if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
913 tree block
= gimple_block (stmt
);
914 gimple_set_location (stmt
, loc
);
915 gimple_set_block (stmt
, block
);
920 region
= outer_state
->tf
->try_finally_expr
;
921 collect_finally_tree_1 (new_seq
, region
);
926 /* A subroutine of lower_try_finally. Create a fallthru label for
927 the given try_finally state. The only tricky bit here is that
928 we have to make sure to record the label in our outer context. */
931 lower_try_finally_fallthru_label (struct leh_tf_state
*tf
)
933 tree label
= tf
->fallthru_label
;
938 label
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
939 tf
->fallthru_label
= label
;
943 record_in_finally_tree (temp
, tf
->outer
->tf
->try_finally_expr
);
949 /* A subroutine of lower_try_finally. If FINALLY consits of a
950 GIMPLE_EH_ELSE node, return it. */
952 static inline geh_else
*
953 get_eh_else (gimple_seq finally
)
955 gimple
*x
= gimple_seq_first_stmt (finally
);
956 if (gimple_code (x
) == GIMPLE_EH_ELSE
)
958 gcc_assert (gimple_seq_singleton_p (finally
));
959 return as_a
<geh_else
*> (x
);
964 /* A subroutine of lower_try_finally. If the eh_protect_cleanup_actions
965 langhook returns non-null, then the language requires that the exception
966 path out of a try_finally be treated specially. To wit: the code within
967 the finally block may not itself throw an exception. We have two choices
968 here. First we can duplicate the finally block and wrap it in a
969 must_not_throw region. Second, we can generate code like
974 if (fintmp == eh_edge)
975 protect_cleanup_actions;
978 where "fintmp" is the temporary used in the switch statement generation
979 alternative considered below. For the nonce, we always choose the first
982 THIS_STATE may be null if this is a try-cleanup, not a try-finally. */
985 honor_protect_cleanup_actions (struct leh_state
*outer_state
,
986 struct leh_state
*this_state
,
987 struct leh_tf_state
*tf
)
989 gimple_seq finally
= gimple_try_cleanup (tf
->top_p
);
991 /* EH_ELSE doesn't come from user code; only compiler generated stuff.
992 It does need to be handled here, so as to separate the (different)
993 EH path from the normal path. But we should not attempt to wrap
994 it with a must-not-throw node (which indeed gets in the way). */
995 if (geh_else
*eh_else
= get_eh_else (finally
))
997 gimple_try_set_cleanup (tf
->top_p
, gimple_eh_else_n_body (eh_else
));
998 finally
= gimple_eh_else_e_body (eh_else
);
1000 /* Let the ELSE see the exception that's being processed. */
1001 eh_region save_ehp
= this_state
->ehp_region
;
1002 this_state
->ehp_region
= this_state
->cur_region
;
1003 lower_eh_constructs_1 (this_state
, &finally
);
1004 this_state
->ehp_region
= save_ehp
;
1008 /* First check for nothing to do. */
1009 if (lang_hooks
.eh_protect_cleanup_actions
== NULL
)
1011 tree actions
= lang_hooks
.eh_protect_cleanup_actions ();
1012 if (actions
== NULL
)
1016 finally
= lower_try_finally_dup_block (finally
, outer_state
,
1017 gimple_location (tf
->try_finally_expr
));
1019 /* If this cleanup consists of a TRY_CATCH_EXPR with TRY_CATCH_IS_CLEANUP
1020 set, the handler of the TRY_CATCH_EXPR is another cleanup which ought
1021 to be in an enclosing scope, but needs to be implemented at this level
1022 to avoid a nesting violation (see wrap_temporary_cleanups in
1023 cp/decl.c). Since it's logically at an outer level, we should call
1024 terminate before we get to it, so strip it away before adding the
1025 MUST_NOT_THROW filter. */
1026 gimple_stmt_iterator gsi
= gsi_start (finally
);
1027 gimple
*x
= gsi_stmt (gsi
);
1028 if (gimple_code (x
) == GIMPLE_TRY
1029 && gimple_try_kind (x
) == GIMPLE_TRY_CATCH
1030 && gimple_try_catch_is_cleanup (x
))
1032 gsi_insert_seq_before (&gsi
, gimple_try_eval (x
), GSI_SAME_STMT
);
1033 gsi_remove (&gsi
, false);
1036 /* Wrap the block with protect_cleanup_actions as the action. */
1037 geh_mnt
*eh_mnt
= gimple_build_eh_must_not_throw (actions
);
1038 gtry
*try_stmt
= gimple_build_try (finally
,
1039 gimple_seq_alloc_with_stmt (eh_mnt
),
1041 finally
= lower_eh_must_not_throw (outer_state
, try_stmt
);
1044 /* Drop all of this into the exception sequence. */
1045 emit_post_landing_pad (&eh_seq
, tf
->region
);
1046 gimple_seq_add_seq (&eh_seq
, finally
);
1047 if (gimple_seq_may_fallthru (finally
))
1048 emit_resx (&eh_seq
, tf
->region
);
1050 /* Having now been handled, EH isn't to be considered with
1051 the rest of the outgoing edges. */
1052 tf
->may_throw
= false;
1055 /* A subroutine of lower_try_finally. We have determined that there is
1056 no fallthru edge out of the finally block. This means that there is
1057 no outgoing edge corresponding to any incoming edge. Restructure the
1058 try_finally node for this special case. */
1061 lower_try_finally_nofallthru (struct leh_state
*state
,
1062 struct leh_tf_state
*tf
)
1068 struct goto_queue_node
*q
, *qe
;
1070 lab
= create_artificial_label (gimple_location (tf
->try_finally_expr
));
1072 /* We expect that tf->top_p is a GIMPLE_TRY. */
1073 finally
= gimple_try_cleanup (tf
->top_p
);
1074 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1076 x
= gimple_build_label (lab
);
1077 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1080 qe
= q
+ tf
->goto_queue_active
;
1083 do_return_redirection (q
, lab
, NULL
);
1085 do_goto_redirection (q
, lab
, NULL
, tf
);
1087 replace_goto_queue (tf
);
1089 /* Emit the finally block into the stream. Lower EH_ELSE at this time. */
1090 eh_else
= get_eh_else (finally
);
1093 finally
= gimple_eh_else_n_body (eh_else
);
1094 lower_eh_constructs_1 (state
, &finally
);
1095 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1099 finally
= gimple_eh_else_e_body (eh_else
);
1100 lower_eh_constructs_1 (state
, &finally
);
1102 emit_post_landing_pad (&eh_seq
, tf
->region
);
1103 gimple_seq_add_seq (&eh_seq
, finally
);
1108 lower_eh_constructs_1 (state
, &finally
);
1109 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1113 emit_post_landing_pad (&eh_seq
, tf
->region
);
1115 x
= gimple_build_goto (lab
);
1116 gimple_set_location (x
, gimple_location (tf
->try_finally_expr
));
1117 gimple_seq_add_stmt (&eh_seq
, x
);
1122 /* A subroutine of lower_try_finally. We have determined that there is
1123 exactly one destination of the finally block. Restructure the
1124 try_finally node for this special case. */
1127 lower_try_finally_onedest (struct leh_state
*state
, struct leh_tf_state
*tf
)
1129 struct goto_queue_node
*q
, *qe
;
1134 gimple_stmt_iterator gsi
;
1136 location_t loc
= gimple_location (tf
->try_finally_expr
);
1138 finally
= gimple_try_cleanup (tf
->top_p
);
1139 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1141 /* Since there's only one destination, and the destination edge can only
1142 either be EH or non-EH, that implies that all of our incoming edges
1143 are of the same type. Therefore we can lower EH_ELSE immediately. */
1144 eh_else
= get_eh_else (finally
);
1148 finally
= gimple_eh_else_e_body (eh_else
);
1150 finally
= gimple_eh_else_n_body (eh_else
);
1153 lower_eh_constructs_1 (state
, &finally
);
1155 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1157 gimple
*stmt
= gsi_stmt (gsi
);
1158 if (LOCATION_LOCUS (gimple_location (stmt
)) == UNKNOWN_LOCATION
)
1160 tree block
= gimple_block (stmt
);
1161 gimple_set_location (stmt
, gimple_location (tf
->try_finally_expr
));
1162 gimple_set_block (stmt
, block
);
1168 /* Only reachable via the exception edge. Add the given label to
1169 the head of the FINALLY block. Append a RESX at the end. */
1170 emit_post_landing_pad (&eh_seq
, tf
->region
);
1171 gimple_seq_add_seq (&eh_seq
, finally
);
1172 emit_resx (&eh_seq
, tf
->region
);
1176 if (tf
->may_fallthru
)
1178 /* Only reachable via the fallthru edge. Do nothing but let
1179 the two blocks run together; we'll fall out the bottom. */
1180 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1184 finally_label
= create_artificial_label (loc
);
1185 label_stmt
= gimple_build_label (finally_label
);
1186 gimple_seq_add_stmt (&tf
->top_p_seq
, label_stmt
);
1188 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1191 qe
= q
+ tf
->goto_queue_active
;
1195 /* Reachable by return expressions only. Redirect them. */
1197 do_return_redirection (q
, finally_label
, NULL
);
1198 replace_goto_queue (tf
);
1202 /* Reachable by goto expressions only. Redirect them. */
1204 do_goto_redirection (q
, finally_label
, NULL
, tf
);
1205 replace_goto_queue (tf
);
1207 if (tf
->dest_array
[0] == tf
->fallthru_label
)
1209 /* Reachable by goto to fallthru label only. Redirect it
1210 to the new label (already created, sadly), and do not
1211 emit the final branch out, or the fallthru label. */
1212 tf
->fallthru_label
= NULL
;
1217 /* Place the original return/goto to the original destination
1218 immediately after the finally block. */
1219 x
= tf
->goto_queue
[0].cont_stmt
;
1220 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1221 maybe_record_in_goto_queue (state
, x
);
1224 /* A subroutine of lower_try_finally. There are multiple edges incoming
1225 and outgoing from the finally block. Implement this by duplicating the
1226 finally block for every destination. */
1229 lower_try_finally_copy (struct leh_state
*state
, struct leh_tf_state
*tf
)
1232 gimple_seq new_stmt
;
1237 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1239 finally
= gimple_try_cleanup (tf
->top_p
);
1241 /* Notice EH_ELSE, and simplify some of the remaining code
1242 by considering FINALLY to be the normal return path only. */
1243 eh_else
= get_eh_else (finally
);
1245 finally
= gimple_eh_else_n_body (eh_else
);
1247 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1250 if (tf
->may_fallthru
)
1252 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1253 lower_eh_constructs_1 (state
, &seq
);
1254 gimple_seq_add_seq (&new_stmt
, seq
);
1256 tmp
= lower_try_finally_fallthru_label (tf
);
1257 x
= gimple_build_goto (tmp
);
1258 gimple_set_location (x
, tf_loc
);
1259 gimple_seq_add_stmt (&new_stmt
, x
);
1264 /* We don't need to copy the EH path of EH_ELSE,
1265 since it is only emitted once. */
1267 seq
= gimple_eh_else_e_body (eh_else
);
1269 seq
= lower_try_finally_dup_block (finally
, state
, tf_loc
);
1270 lower_eh_constructs_1 (state
, &seq
);
1272 emit_post_landing_pad (&eh_seq
, tf
->region
);
1273 gimple_seq_add_seq (&eh_seq
, seq
);
1274 emit_resx (&eh_seq
, tf
->region
);
1279 struct goto_queue_node
*q
, *qe
;
1280 int return_index
, index
;
1283 struct goto_queue_node
*q
;
1287 return_index
= tf
->dest_array
.length ();
1288 labels
= XCNEWVEC (struct labels_s
, return_index
+ 1);
1291 qe
= q
+ tf
->goto_queue_active
;
1294 index
= q
->index
< 0 ? return_index
: q
->index
;
1296 if (!labels
[index
].q
)
1297 labels
[index
].q
= q
;
1300 for (index
= 0; index
< return_index
+ 1; index
++)
1304 q
= labels
[index
].q
;
1308 lab
= labels
[index
].label
1309 = create_artificial_label (tf_loc
);
1311 if (index
== return_index
)
1312 do_return_redirection (q
, lab
, NULL
);
1314 do_goto_redirection (q
, lab
, NULL
, tf
);
1316 x
= gimple_build_label (lab
);
1317 gimple_seq_add_stmt (&new_stmt
, x
);
1319 seq
= lower_try_finally_dup_block (finally
, state
, q
->location
);
1320 lower_eh_constructs_1 (state
, &seq
);
1321 gimple_seq_add_seq (&new_stmt
, seq
);
1323 gimple_seq_add_stmt (&new_stmt
, q
->cont_stmt
);
1324 maybe_record_in_goto_queue (state
, q
->cont_stmt
);
1327 for (q
= tf
->goto_queue
; q
< qe
; q
++)
1331 index
= q
->index
< 0 ? return_index
: q
->index
;
1333 if (labels
[index
].q
== q
)
1336 lab
= labels
[index
].label
;
1338 if (index
== return_index
)
1339 do_return_redirection (q
, lab
, NULL
);
1341 do_goto_redirection (q
, lab
, NULL
, tf
);
1344 replace_goto_queue (tf
);
1348 /* Need to link new stmts after running replace_goto_queue due
1349 to not wanting to process the same goto stmts twice. */
1350 gimple_seq_add_seq (&tf
->top_p_seq
, new_stmt
);
1353 /* A subroutine of lower_try_finally. There are multiple edges incoming
1354 and outgoing from the finally block. Implement this by instrumenting
1355 each incoming edge and creating a switch statement at the end of the
1356 finally block that branches to the appropriate destination. */
1359 lower_try_finally_switch (struct leh_state
*state
, struct leh_tf_state
*tf
)
1361 struct goto_queue_node
*q
, *qe
;
1362 tree finally_tmp
, finally_label
;
1363 int return_index
, eh_index
, fallthru_index
;
1364 int nlabels
, ndests
, j
, last_case_index
;
1366 auto_vec
<tree
> case_label_vec
;
1367 gimple_seq switch_body
= NULL
;
1371 gimple
*switch_stmt
;
1373 hash_map
<tree
, gimple
*> *cont_map
= NULL
;
1374 /* The location of the TRY_FINALLY stmt. */
1375 location_t tf_loc
= gimple_location (tf
->try_finally_expr
);
1376 /* The location of the finally block. */
1377 location_t finally_loc
;
1379 finally
= gimple_try_cleanup (tf
->top_p
);
1380 eh_else
= get_eh_else (finally
);
1382 /* Mash the TRY block to the head of the chain. */
1383 tf
->top_p_seq
= gimple_try_eval (tf
->top_p
);
1385 /* The location of the finally is either the last stmt in the finally
1386 block or the location of the TRY_FINALLY itself. */
1387 x
= gimple_seq_last_stmt (finally
);
1388 finally_loc
= x
? gimple_location (x
) : tf_loc
;
1390 /* Prepare for switch statement generation. */
1391 nlabels
= tf
->dest_array
.length ();
1392 return_index
= nlabels
;
1393 eh_index
= return_index
+ tf
->may_return
;
1394 fallthru_index
= eh_index
+ (tf
->may_throw
&& !eh_else
);
1395 ndests
= fallthru_index
+ tf
->may_fallthru
;
1397 finally_tmp
= create_tmp_var (integer_type_node
, "finally_tmp");
1398 finally_label
= create_artificial_label (finally_loc
);
1400 /* We use vec::quick_push on case_label_vec throughout this function,
1401 since we know the size in advance and allocate precisely as muce
1403 case_label_vec
.create (ndests
);
1405 last_case_index
= 0;
1407 /* Begin inserting code for getting to the finally block. Things
1408 are done in this order to correspond to the sequence the code is
1411 if (tf
->may_fallthru
)
1413 x
= gimple_build_assign (finally_tmp
,
1414 build_int_cst (integer_type_node
,
1416 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1418 tmp
= build_int_cst (integer_type_node
, fallthru_index
);
1419 last_case
= build_case_label (tmp
, NULL
,
1420 create_artificial_label (tf_loc
));
1421 case_label_vec
.quick_push (last_case
);
1424 x
= gimple_build_label (CASE_LABEL (last_case
));
1425 gimple_seq_add_stmt (&switch_body
, x
);
1427 tmp
= lower_try_finally_fallthru_label (tf
);
1428 x
= gimple_build_goto (tmp
);
1429 gimple_set_location (x
, tf_loc
);
1430 gimple_seq_add_stmt (&switch_body
, x
);
1433 /* For EH_ELSE, emit the exception path (plus resx) now, then
1434 subsequently we only need consider the normal path. */
1439 finally
= gimple_eh_else_e_body (eh_else
);
1440 lower_eh_constructs_1 (state
, &finally
);
1442 emit_post_landing_pad (&eh_seq
, tf
->region
);
1443 gimple_seq_add_seq (&eh_seq
, finally
);
1444 emit_resx (&eh_seq
, tf
->region
);
1447 finally
= gimple_eh_else_n_body (eh_else
);
1449 else if (tf
->may_throw
)
1451 emit_post_landing_pad (&eh_seq
, tf
->region
);
1453 x
= gimple_build_assign (finally_tmp
,
1454 build_int_cst (integer_type_node
, eh_index
));
1455 gimple_seq_add_stmt (&eh_seq
, x
);
1457 x
= gimple_build_goto (finally_label
);
1458 gimple_set_location (x
, tf_loc
);
1459 gimple_seq_add_stmt (&eh_seq
, x
);
1461 tmp
= build_int_cst (integer_type_node
, eh_index
);
1462 last_case
= build_case_label (tmp
, NULL
,
1463 create_artificial_label (tf_loc
));
1464 case_label_vec
.quick_push (last_case
);
1467 x
= gimple_build_label (CASE_LABEL (last_case
));
1468 gimple_seq_add_stmt (&eh_seq
, x
);
1469 emit_resx (&eh_seq
, tf
->region
);
1472 x
= gimple_build_label (finally_label
);
1473 gimple_seq_add_stmt (&tf
->top_p_seq
, x
);
1475 lower_eh_constructs_1 (state
, &finally
);
1476 gimple_seq_add_seq (&tf
->top_p_seq
, finally
);
1478 /* Redirect each incoming goto edge. */
1480 qe
= q
+ tf
->goto_queue_active
;
1481 j
= last_case_index
+ tf
->may_return
;
1482 /* Prepare the assignments to finally_tmp that are executed upon the
1483 entrance through a particular edge. */
1486 gimple_seq mod
= NULL
;
1488 unsigned int case_index
;
1492 x
= gimple_build_assign (finally_tmp
,
1493 build_int_cst (integer_type_node
,
1495 gimple_seq_add_stmt (&mod
, x
);
1496 do_return_redirection (q
, finally_label
, mod
);
1497 switch_id
= return_index
;
1501 x
= gimple_build_assign (finally_tmp
,
1502 build_int_cst (integer_type_node
, q
->index
));
1503 gimple_seq_add_stmt (&mod
, x
);
1504 do_goto_redirection (q
, finally_label
, mod
, tf
);
1505 switch_id
= q
->index
;
1508 case_index
= j
+ q
->index
;
1509 if (case_label_vec
.length () <= case_index
|| !case_label_vec
[case_index
])
1512 tmp
= build_int_cst (integer_type_node
, switch_id
);
1513 case_lab
= build_case_label (tmp
, NULL
,
1514 create_artificial_label (tf_loc
));
1515 /* We store the cont_stmt in the pointer map, so that we can recover
1516 it in the loop below. */
1518 cont_map
= new hash_map
<tree
, gimple
*>;
1519 cont_map
->put (case_lab
, q
->cont_stmt
);
1520 case_label_vec
.quick_push (case_lab
);
1523 for (j
= last_case_index
; j
< last_case_index
+ nlabels
; j
++)
1527 last_case
= case_label_vec
[j
];
1529 gcc_assert (last_case
);
1530 gcc_assert (cont_map
);
1532 cont_stmt
= *cont_map
->get (last_case
);
1534 x
= gimple_build_label (CASE_LABEL (last_case
));
1535 gimple_seq_add_stmt (&switch_body
, x
);
1536 gimple_seq_add_stmt (&switch_body
, cont_stmt
);
1537 maybe_record_in_goto_queue (state
, cont_stmt
);
1542 replace_goto_queue (tf
);
1544 /* Make sure that the last case is the default label, as one is required.
1545 Then sort the labels, which is also required in GIMPLE. */
1546 CASE_LOW (last_case
) = NULL
;
1547 tree tem
= case_label_vec
.pop ();
1548 gcc_assert (tem
== last_case
);
1549 sort_case_labels (case_label_vec
);
1551 /* Build the switch statement, setting last_case to be the default
1553 switch_stmt
= gimple_build_switch (finally_tmp
, last_case
,
1555 gimple_set_location (switch_stmt
, finally_loc
);
1557 /* Need to link SWITCH_STMT after running replace_goto_queue
1558 due to not wanting to process the same goto stmts twice. */
1559 gimple_seq_add_stmt (&tf
->top_p_seq
, switch_stmt
);
1560 gimple_seq_add_seq (&tf
->top_p_seq
, switch_body
);
1563 /* Decide whether or not we are going to duplicate the finally block.
1564 There are several considerations.
1566 First, if this is Java, then the finally block contains code
1567 written by the user. It has line numbers associated with it,
1568 so duplicating the block means it's difficult to set a breakpoint.
1569 Since controlling code generation via -g is verboten, we simply
1570 never duplicate code without optimization.
1572 Second, we'd like to prevent egregious code growth. One way to
1573 do this is to estimate the size of the finally block, multiply
1574 that by the number of copies we'd need to make, and compare against
1575 the estimate of the size of the switch machinery we'd have to add. */
1578 decide_copy_try_finally (int ndests
, bool may_throw
, gimple_seq finally
)
1580 int f_estimate
, sw_estimate
;
1583 /* If there's an EH_ELSE involved, the exception path is separate
1584 and really doesn't come into play for this computation. */
1585 eh_else
= get_eh_else (finally
);
1588 ndests
-= may_throw
;
1589 finally
= gimple_eh_else_n_body (eh_else
);
1594 gimple_stmt_iterator gsi
;
1599 for (gsi
= gsi_start (finally
); !gsi_end_p (gsi
); gsi_next (&gsi
))
1601 /* Duplicate __builtin_stack_restore in the hope of eliminating it
1602 on the EH paths and, consequently, useless cleanups. */
1603 gimple
*stmt
= gsi_stmt (gsi
);
1604 if (!is_gimple_debug (stmt
)
1605 && !gimple_clobber_p (stmt
)
1606 && !gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
1612 /* Finally estimate N times, plus N gotos. */
1613 f_estimate
= estimate_num_insns_seq (finally
, &eni_size_weights
);
1614 f_estimate
= (f_estimate
+ 1) * ndests
;
1616 /* Switch statement (cost 10), N variable assignments, N gotos. */
1617 sw_estimate
= 10 + 2 * ndests
;
1619 /* Optimize for size clearly wants our best guess. */
1620 if (optimize_function_for_size_p (cfun
))
1621 return f_estimate
< sw_estimate
;
1623 /* ??? These numbers are completely made up so far. */
1625 return f_estimate
< 100 || f_estimate
< sw_estimate
* 2;
1627 return f_estimate
< 40 || f_estimate
* 2 < sw_estimate
* 3;
1630 /* REG is the enclosing region for a possible cleanup region, or the region
1631 itself. Returns TRUE if such a region would be unreachable.
1633 Cleanup regions within a must-not-throw region aren't actually reachable
1634 even if there are throwing stmts within them, because the personality
1635 routine will call terminate before unwinding. */
1638 cleanup_is_dead_in (eh_region reg
)
1640 while (reg
&& reg
->type
== ERT_CLEANUP
)
1642 return (reg
&& reg
->type
== ERT_MUST_NOT_THROW
);
1645 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_FINALLY nodes
1646 to a sequence of labels and blocks, plus the exception region trees
1647 that record all the magic. This is complicated by the need to
1648 arrange for the FINALLY block to be executed on all exits. */
1651 lower_try_finally (struct leh_state
*state
, gtry
*tp
)
1653 struct leh_tf_state this_tf
;
1654 struct leh_state this_state
;
1656 gimple_seq old_eh_seq
;
1658 /* Process the try block. */
1660 memset (&this_tf
, 0, sizeof (this_tf
));
1661 this_tf
.try_finally_expr
= tp
;
1663 this_tf
.outer
= state
;
1664 if (using_eh_for_cleanups_p () && !cleanup_is_dead_in (state
->cur_region
))
1666 this_tf
.region
= gen_eh_region_cleanup (state
->cur_region
);
1667 this_state
.cur_region
= this_tf
.region
;
1671 this_tf
.region
= NULL
;
1672 this_state
.cur_region
= state
->cur_region
;
1675 this_state
.ehp_region
= state
->ehp_region
;
1676 this_state
.tf
= &this_tf
;
1678 old_eh_seq
= eh_seq
;
1681 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1683 /* Determine if the try block is escaped through the bottom. */
1684 this_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1686 /* Determine if any exceptions are possible within the try block. */
1688 this_tf
.may_throw
= eh_region_may_contain_throw (this_tf
.region
);
1689 if (this_tf
.may_throw
)
1690 honor_protect_cleanup_actions (state
, &this_state
, &this_tf
);
1692 /* Determine how many edges (still) reach the finally block. Or rather,
1693 how many destinations are reached by the finally block. Use this to
1694 determine how we process the finally block itself. */
1696 ndests
= this_tf
.dest_array
.length ();
1697 ndests
+= this_tf
.may_fallthru
;
1698 ndests
+= this_tf
.may_return
;
1699 ndests
+= this_tf
.may_throw
;
1701 /* If the FINALLY block is not reachable, dike it out. */
1704 gimple_seq_add_seq (&this_tf
.top_p_seq
, gimple_try_eval (tp
));
1705 gimple_try_set_cleanup (tp
, NULL
);
1707 /* If the finally block doesn't fall through, then any destination
1708 we might try to impose there isn't reached either. There may be
1709 some minor amount of cleanup and redirection still needed. */
1710 else if (!gimple_seq_may_fallthru (gimple_try_cleanup (tp
)))
1711 lower_try_finally_nofallthru (state
, &this_tf
);
1713 /* We can easily special-case redirection to a single destination. */
1714 else if (ndests
== 1)
1715 lower_try_finally_onedest (state
, &this_tf
);
1716 else if (decide_copy_try_finally (ndests
, this_tf
.may_throw
,
1717 gimple_try_cleanup (tp
)))
1718 lower_try_finally_copy (state
, &this_tf
);
1720 lower_try_finally_switch (state
, &this_tf
);
1722 /* If someone requested we add a label at the end of the transformed
1724 if (this_tf
.fallthru_label
)
1726 /* This must be reached only if ndests == 0. */
1727 gimple
*x
= gimple_build_label (this_tf
.fallthru_label
);
1728 gimple_seq_add_stmt (&this_tf
.top_p_seq
, x
);
1731 this_tf
.dest_array
.release ();
1732 free (this_tf
.goto_queue
);
1733 if (this_tf
.goto_queue_map
)
1734 delete this_tf
.goto_queue_map
;
1736 /* If there was an old (aka outer) eh_seq, append the current eh_seq.
1737 If there was no old eh_seq, then the append is trivially already done. */
1741 eh_seq
= old_eh_seq
;
1744 gimple_seq new_eh_seq
= eh_seq
;
1745 eh_seq
= old_eh_seq
;
1746 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1750 return this_tf
.top_p_seq
;
1753 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY_CATCH with a
1754 list of GIMPLE_CATCH to a sequence of labels and blocks, plus the
1755 exception region trees that records all the magic. */
1758 lower_catch (struct leh_state
*state
, gtry
*tp
)
1760 eh_region try_region
= NULL
;
1761 struct leh_state this_state
= *state
;
1762 gimple_stmt_iterator gsi
;
1764 gimple_seq new_seq
, cleanup
;
1766 location_t try_catch_loc
= gimple_location (tp
);
1768 if (flag_exceptions
)
1770 try_region
= gen_eh_region_try (state
->cur_region
);
1771 this_state
.cur_region
= try_region
;
1774 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1776 if (!eh_region_may_contain_throw (try_region
))
1777 return gimple_try_eval (tp
);
1780 emit_eh_dispatch (&new_seq
, try_region
);
1781 emit_resx (&new_seq
, try_region
);
1783 this_state
.cur_region
= state
->cur_region
;
1784 this_state
.ehp_region
= try_region
;
1786 /* Add eh_seq from lowering EH in the cleanup sequence after the cleanup
1787 itself, so that e.g. for coverage purposes the nested cleanups don't
1788 appear before the cleanup body. See PR64634 for details. */
1789 gimple_seq old_eh_seq
= eh_seq
;
1793 cleanup
= gimple_try_cleanup (tp
);
1794 for (gsi
= gsi_start (cleanup
);
1802 catch_stmt
= as_a
<gcatch
*> (gsi_stmt (gsi
));
1803 c
= gen_eh_region_catch (try_region
, gimple_catch_types (catch_stmt
));
1805 handler
= gimple_catch_handler (catch_stmt
);
1806 lower_eh_constructs_1 (&this_state
, &handler
);
1808 c
->label
= create_artificial_label (UNKNOWN_LOCATION
);
1809 x
= gimple_build_label (c
->label
);
1810 gimple_seq_add_stmt (&new_seq
, x
);
1812 gimple_seq_add_seq (&new_seq
, handler
);
1814 if (gimple_seq_may_fallthru (new_seq
))
1817 out_label
= create_artificial_label (try_catch_loc
);
1819 x
= gimple_build_goto (out_label
);
1820 gimple_seq_add_stmt (&new_seq
, x
);
1826 gimple_try_set_cleanup (tp
, new_seq
);
1828 gimple_seq new_eh_seq
= eh_seq
;
1829 eh_seq
= old_eh_seq
;
1830 gimple_seq ret_seq
= frob_into_branch_around (tp
, try_region
, out_label
);
1831 gimple_seq_add_seq (&eh_seq
, new_eh_seq
);
1835 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with a
1836 GIMPLE_EH_FILTER to a sequence of labels and blocks, plus the exception
1837 region trees that record all the magic. */
1840 lower_eh_filter (struct leh_state
*state
, gtry
*tp
)
1842 struct leh_state this_state
= *state
;
1843 eh_region this_region
= NULL
;
1847 inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1849 if (flag_exceptions
)
1851 this_region
= gen_eh_region_allowed (state
->cur_region
,
1852 gimple_eh_filter_types (inner
));
1853 this_state
.cur_region
= this_region
;
1856 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1858 if (!eh_region_may_contain_throw (this_region
))
1859 return gimple_try_eval (tp
);
1862 this_state
.cur_region
= state
->cur_region
;
1863 this_state
.ehp_region
= this_region
;
1865 emit_eh_dispatch (&new_seq
, this_region
);
1866 emit_resx (&new_seq
, this_region
);
1868 this_region
->u
.allowed
.label
= create_artificial_label (UNKNOWN_LOCATION
);
1869 x
= gimple_build_label (this_region
->u
.allowed
.label
);
1870 gimple_seq_add_stmt (&new_seq
, x
);
1872 lower_eh_constructs_1 (&this_state
, gimple_eh_filter_failure_ptr (inner
));
1873 gimple_seq_add_seq (&new_seq
, gimple_eh_filter_failure (inner
));
1875 gimple_try_set_cleanup (tp
, new_seq
);
1877 return frob_into_branch_around (tp
, this_region
, NULL
);
1880 /* A subroutine of lower_eh_constructs_1. Lower a GIMPLE_TRY with
1881 an GIMPLE_EH_MUST_NOT_THROW to a sequence of labels and blocks,
1882 plus the exception region trees that record all the magic. */
1885 lower_eh_must_not_throw (struct leh_state
*state
, gtry
*tp
)
1887 struct leh_state this_state
= *state
;
1889 if (flag_exceptions
)
1891 gimple
*inner
= gimple_seq_first_stmt (gimple_try_cleanup (tp
));
1892 eh_region this_region
;
1894 this_region
= gen_eh_region_must_not_throw (state
->cur_region
);
1895 this_region
->u
.must_not_throw
.failure_decl
1896 = gimple_eh_must_not_throw_fndecl (
1897 as_a
<geh_mnt
*> (inner
));
1898 this_region
->u
.must_not_throw
.failure_loc
1899 = LOCATION_LOCUS (gimple_location (tp
));
1901 /* In order to get mangling applied to this decl, we must mark it
1902 used now. Otherwise, pass_ipa_free_lang_data won't think it
1904 TREE_USED (this_region
->u
.must_not_throw
.failure_decl
) = 1;
1906 this_state
.cur_region
= this_region
;
1909 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1911 return gimple_try_eval (tp
);
1914 /* Implement a cleanup expression. This is similar to try-finally,
1915 except that we only execute the cleanup block for exception edges. */
1918 lower_cleanup (struct leh_state
*state
, gtry
*tp
)
1920 struct leh_state this_state
= *state
;
1921 eh_region this_region
= NULL
;
1922 struct leh_tf_state fake_tf
;
1924 bool cleanup_dead
= cleanup_is_dead_in (state
->cur_region
);
1926 if (flag_exceptions
&& !cleanup_dead
)
1928 this_region
= gen_eh_region_cleanup (state
->cur_region
);
1929 this_state
.cur_region
= this_region
;
1932 lower_eh_constructs_1 (&this_state
, gimple_try_eval_ptr (tp
));
1934 if (cleanup_dead
|| !eh_region_may_contain_throw (this_region
))
1935 return gimple_try_eval (tp
);
1937 /* Build enough of a try-finally state so that we can reuse
1938 honor_protect_cleanup_actions. */
1939 memset (&fake_tf
, 0, sizeof (fake_tf
));
1940 fake_tf
.top_p
= fake_tf
.try_finally_expr
= tp
;
1941 fake_tf
.outer
= state
;
1942 fake_tf
.region
= this_region
;
1943 fake_tf
.may_fallthru
= gimple_seq_may_fallthru (gimple_try_eval (tp
));
1944 fake_tf
.may_throw
= true;
1946 honor_protect_cleanup_actions (state
, NULL
, &fake_tf
);
1948 if (fake_tf
.may_throw
)
1950 /* In this case honor_protect_cleanup_actions had nothing to do,
1951 and we should process this normally. */
1952 lower_eh_constructs_1 (state
, gimple_try_cleanup_ptr (tp
));
1953 result
= frob_into_branch_around (tp
, this_region
,
1954 fake_tf
.fallthru_label
);
1958 /* In this case honor_protect_cleanup_actions did nearly all of
1959 the work. All we have left is to append the fallthru_label. */
1961 result
= gimple_try_eval (tp
);
1962 if (fake_tf
.fallthru_label
)
1964 gimple
*x
= gimple_build_label (fake_tf
.fallthru_label
);
1965 gimple_seq_add_stmt (&result
, x
);
1971 /* Main loop for lowering eh constructs. Also moves gsi to the next
1975 lower_eh_constructs_2 (struct leh_state
*state
, gimple_stmt_iterator
*gsi
)
1979 gimple
*stmt
= gsi_stmt (*gsi
);
1981 switch (gimple_code (stmt
))
1985 tree fndecl
= gimple_call_fndecl (stmt
);
1988 if (fndecl
&& DECL_BUILT_IN_CLASS (fndecl
) == BUILT_IN_NORMAL
)
1989 switch (DECL_FUNCTION_CODE (fndecl
))
1991 case BUILT_IN_EH_POINTER
:
1992 /* The front end may have generated a call to
1993 __builtin_eh_pointer (0) within a catch region. Replace
1994 this zero argument with the current catch region number. */
1995 if (state
->ehp_region
)
1997 tree nr
= build_int_cst (integer_type_node
,
1998 state
->ehp_region
->index
);
1999 gimple_call_set_arg (stmt
, 0, nr
);
2003 /* The user has dome something silly. Remove it. */
2004 rhs
= null_pointer_node
;
2009 case BUILT_IN_EH_FILTER
:
2010 /* ??? This should never appear, but since it's a builtin it
2011 is accessible to abuse by users. Just remove it and
2012 replace the use with the arbitrary value zero. */
2013 rhs
= build_int_cst (TREE_TYPE (TREE_TYPE (fndecl
)), 0);
2015 lhs
= gimple_call_lhs (stmt
);
2016 x
= gimple_build_assign (lhs
, rhs
);
2017 gsi_insert_before (gsi
, x
, GSI_SAME_STMT
);
2020 case BUILT_IN_EH_COPY_VALUES
:
2021 /* Likewise this should not appear. Remove it. */
2022 gsi_remove (gsi
, true);
2032 /* If the stmt can throw use a new temporary for the assignment
2033 to a LHS. This makes sure the old value of the LHS is
2034 available on the EH edge. Only do so for statements that
2035 potentially fall through (no noreturn calls e.g.), otherwise
2036 this new assignment might create fake fallthru regions. */
2037 if (stmt_could_throw_p (stmt
)
2038 && gimple_has_lhs (stmt
)
2039 && gimple_stmt_may_fallthru (stmt
)
2040 && !tree_could_throw_p (gimple_get_lhs (stmt
))
2041 && is_gimple_reg_type (TREE_TYPE (gimple_get_lhs (stmt
))))
2043 tree lhs
= gimple_get_lhs (stmt
);
2044 tree tmp
= create_tmp_var (TREE_TYPE (lhs
));
2045 gimple
*s
= gimple_build_assign (lhs
, tmp
);
2046 gimple_set_location (s
, gimple_location (stmt
));
2047 gimple_set_block (s
, gimple_block (stmt
));
2048 gimple_set_lhs (stmt
, tmp
);
2049 if (TREE_CODE (TREE_TYPE (tmp
)) == COMPLEX_TYPE
2050 || TREE_CODE (TREE_TYPE (tmp
)) == VECTOR_TYPE
)
2051 DECL_GIMPLE_REG_P (tmp
) = 1;
2052 gsi_insert_after (gsi
, s
, GSI_SAME_STMT
);
2054 /* Look for things that can throw exceptions, and record them. */
2055 if (state
->cur_region
&& stmt_could_throw_p (stmt
))
2057 record_stmt_eh_region (state
->cur_region
, stmt
);
2058 note_eh_region_may_contain_throw (state
->cur_region
);
2065 maybe_record_in_goto_queue (state
, stmt
);
2069 verify_norecord_switch_expr (state
, as_a
<gswitch
*> (stmt
));
2074 gtry
*try_stmt
= as_a
<gtry
*> (stmt
);
2075 if (gimple_try_kind (try_stmt
) == GIMPLE_TRY_FINALLY
)
2076 replace
= lower_try_finally (state
, try_stmt
);
2079 x
= gimple_seq_first_stmt (gimple_try_cleanup (try_stmt
));
2082 replace
= gimple_try_eval (try_stmt
);
2083 lower_eh_constructs_1 (state
, &replace
);
2086 switch (gimple_code (x
))
2089 replace
= lower_catch (state
, try_stmt
);
2091 case GIMPLE_EH_FILTER
:
2092 replace
= lower_eh_filter (state
, try_stmt
);
2094 case GIMPLE_EH_MUST_NOT_THROW
:
2095 replace
= lower_eh_must_not_throw (state
, try_stmt
);
2097 case GIMPLE_EH_ELSE
:
2098 /* This code is only valid with GIMPLE_TRY_FINALLY. */
2101 replace
= lower_cleanup (state
, try_stmt
);
2107 /* Remove the old stmt and insert the transformed sequence
2109 gsi_insert_seq_before (gsi
, replace
, GSI_SAME_STMT
);
2110 gsi_remove (gsi
, true);
2112 /* Return since we don't want gsi_next () */
2115 case GIMPLE_EH_ELSE
:
2116 /* We should be eliminating this in lower_try_finally et al. */
2120 /* A type, a decl, or some kind of statement that we're not
2121 interested in. Don't walk them. */
2128 /* A helper to unwrap a gimple_seq and feed stmts to lower_eh_constructs_2. */
2131 lower_eh_constructs_1 (struct leh_state
*state
, gimple_seq
*pseq
)
2133 gimple_stmt_iterator gsi
;
2134 for (gsi
= gsi_start (*pseq
); !gsi_end_p (gsi
);)
2135 lower_eh_constructs_2 (state
, &gsi
);
2140 const pass_data pass_data_lower_eh
=
2142 GIMPLE_PASS
, /* type */
2144 OPTGROUP_NONE
, /* optinfo_flags */
2145 TV_TREE_EH
, /* tv_id */
2146 PROP_gimple_lcf
, /* properties_required */
2147 PROP_gimple_leh
, /* properties_provided */
2148 0, /* properties_destroyed */
2149 0, /* todo_flags_start */
2150 0, /* todo_flags_finish */
2153 class pass_lower_eh
: public gimple_opt_pass
2156 pass_lower_eh (gcc::context
*ctxt
)
2157 : gimple_opt_pass (pass_data_lower_eh
, ctxt
)
2160 /* opt_pass methods: */
2161 virtual unsigned int execute (function
*);
2163 }; // class pass_lower_eh
2166 pass_lower_eh::execute (function
*fun
)
2168 struct leh_state null_state
;
2171 bodyp
= gimple_body (current_function_decl
);
2175 finally_tree
= new hash_table
<finally_tree_hasher
> (31);
2176 eh_region_may_contain_throw_map
= BITMAP_ALLOC (NULL
);
2177 memset (&null_state
, 0, sizeof (null_state
));
2179 collect_finally_tree_1 (bodyp
, NULL
);
2180 lower_eh_constructs_1 (&null_state
, &bodyp
);
2181 gimple_set_body (current_function_decl
, bodyp
);
2183 /* We assume there's a return statement, or something, at the end of
2184 the function, and thus ploping the EH sequence afterward won't
2186 gcc_assert (!gimple_seq_may_fallthru (bodyp
));
2187 gimple_seq_add_seq (&bodyp
, eh_seq
);
2189 /* We assume that since BODYP already existed, adding EH_SEQ to it
2190 didn't change its value, and we don't have to re-set the function. */
2191 gcc_assert (bodyp
== gimple_body (current_function_decl
));
2193 delete finally_tree
;
2194 finally_tree
= NULL
;
2195 BITMAP_FREE (eh_region_may_contain_throw_map
);
2198 /* If this function needs a language specific EH personality routine
2199 and the frontend didn't already set one do so now. */
2200 if (function_needs_eh_personality (fun
) == eh_personality_lang
2201 && !DECL_FUNCTION_PERSONALITY (current_function_decl
))
2202 DECL_FUNCTION_PERSONALITY (current_function_decl
)
2203 = lang_hooks
.eh_personality ();
2211 make_pass_lower_eh (gcc::context
*ctxt
)
2213 return new pass_lower_eh (ctxt
);
2216 /* Create the multiple edges from an EH_DISPATCH statement to all of
2217 the possible handlers for its EH region. Return true if there's
2218 no fallthru edge; false if there is. */
2221 make_eh_dispatch_edges (geh_dispatch
*stmt
)
2225 basic_block src
, dst
;
2227 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2228 src
= gimple_bb (stmt
);
2233 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2235 dst
= label_to_block (c
->label
);
2236 make_edge (src
, dst
, 0);
2238 /* A catch-all handler doesn't have a fallthru. */
2239 if (c
->type_list
== NULL
)
2244 case ERT_ALLOWED_EXCEPTIONS
:
2245 dst
= label_to_block (r
->u
.allowed
.label
);
2246 make_edge (src
, dst
, 0);
2256 /* Create the single EH edge from STMT to its nearest landing pad,
2257 if there is such a landing pad within the current function. */
2260 make_eh_edges (gimple
*stmt
)
2262 basic_block src
, dst
;
2266 lp_nr
= lookup_stmt_eh_lp (stmt
);
2270 lp
= get_eh_landing_pad_from_number (lp_nr
);
2271 gcc_assert (lp
!= NULL
);
2273 src
= gimple_bb (stmt
);
2274 dst
= label_to_block (lp
->post_landing_pad
);
2275 make_edge (src
, dst
, EDGE_EH
);
2278 /* Do the work in redirecting EDGE_IN to NEW_BB within the EH region tree;
2279 do not actually perform the final edge redirection.
2281 CHANGE_REGION is true when we're being called from cleanup_empty_eh and
2282 we intend to change the destination EH region as well; this means
2283 EH_LANDING_PAD_NR must already be set on the destination block label.
2284 If false, we're being called from generic cfg manipulation code and we
2285 should preserve our place within the region tree. */
2288 redirect_eh_edge_1 (edge edge_in
, basic_block new_bb
, bool change_region
)
2290 eh_landing_pad old_lp
, new_lp
;
2293 int old_lp_nr
, new_lp_nr
;
2294 tree old_label
, new_label
;
2298 old_bb
= edge_in
->dest
;
2299 old_label
= gimple_block_label (old_bb
);
2300 old_lp_nr
= EH_LANDING_PAD_NR (old_label
);
2301 gcc_assert (old_lp_nr
> 0);
2302 old_lp
= get_eh_landing_pad_from_number (old_lp_nr
);
2304 throw_stmt
= last_stmt (edge_in
->src
);
2305 gcc_assert (lookup_stmt_eh_lp (throw_stmt
) == old_lp_nr
);
2307 new_label
= gimple_block_label (new_bb
);
2309 /* Look for an existing region that might be using NEW_BB already. */
2310 new_lp_nr
= EH_LANDING_PAD_NR (new_label
);
2313 new_lp
= get_eh_landing_pad_from_number (new_lp_nr
);
2314 gcc_assert (new_lp
);
2316 /* Unless CHANGE_REGION is true, the new and old landing pad
2317 had better be associated with the same EH region. */
2318 gcc_assert (change_region
|| new_lp
->region
== old_lp
->region
);
2323 gcc_assert (!change_region
);
2326 /* Notice when we redirect the last EH edge away from OLD_BB. */
2327 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
2328 if (e
!= edge_in
&& (e
->flags
& EDGE_EH
))
2333 /* NEW_LP already exists. If there are still edges into OLD_LP,
2334 there's nothing to do with the EH tree. If there are no more
2335 edges into OLD_LP, then we want to remove OLD_LP as it is unused.
2336 If CHANGE_REGION is true, then our caller is expecting to remove
2338 if (e
== NULL
&& !change_region
)
2339 remove_eh_landing_pad (old_lp
);
2343 /* No correct landing pad exists. If there are no more edges
2344 into OLD_LP, then we can simply re-use the existing landing pad.
2345 Otherwise, we have to create a new landing pad. */
2348 EH_LANDING_PAD_NR (old_lp
->post_landing_pad
) = 0;
2352 new_lp
= gen_eh_landing_pad (old_lp
->region
);
2353 new_lp
->post_landing_pad
= new_label
;
2354 EH_LANDING_PAD_NR (new_label
) = new_lp
->index
;
2357 /* Maybe move the throwing statement to the new region. */
2358 if (old_lp
!= new_lp
)
2360 remove_stmt_from_eh_lp (throw_stmt
);
2361 add_stmt_to_eh_lp (throw_stmt
, new_lp
->index
);
2365 /* Redirect EH edge E to NEW_BB. */
2368 redirect_eh_edge (edge edge_in
, basic_block new_bb
)
2370 redirect_eh_edge_1 (edge_in
, new_bb
, false);
2371 return ssa_redirect_edge (edge_in
, new_bb
);
2374 /* This is a subroutine of gimple_redirect_edge_and_branch. Update the
2375 labels for redirecting a non-fallthru EH_DISPATCH edge E to NEW_BB.
2376 The actual edge update will happen in the caller. */
2379 redirect_eh_dispatch_edge (geh_dispatch
*stmt
, edge e
, basic_block new_bb
)
2381 tree new_lab
= gimple_block_label (new_bb
);
2382 bool any_changed
= false;
2387 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
2391 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
2393 old_bb
= label_to_block (c
->label
);
2394 if (old_bb
== e
->dest
)
2402 case ERT_ALLOWED_EXCEPTIONS
:
2403 old_bb
= label_to_block (r
->u
.allowed
.label
);
2404 gcc_assert (old_bb
== e
->dest
);
2405 r
->u
.allowed
.label
= new_lab
;
2413 gcc_assert (any_changed
);
2416 /* Helper function for operation_could_trap_p and stmt_could_throw_p. */
2419 operation_could_trap_helper_p (enum tree_code op
,
2430 case TRUNC_DIV_EXPR
:
2432 case FLOOR_DIV_EXPR
:
2433 case ROUND_DIV_EXPR
:
2434 case EXACT_DIV_EXPR
:
2436 case FLOOR_MOD_EXPR
:
2437 case ROUND_MOD_EXPR
:
2438 case TRUNC_MOD_EXPR
:
2440 if (honor_snans
|| honor_trapv
)
2443 return flag_trapping_math
;
2444 if (!TREE_CONSTANT (divisor
) || integer_zerop (divisor
))
2453 /* Some floating point comparisons may trap. */
2458 case UNORDERED_EXPR
:
2470 /* These operations don't trap with floating point. */
2478 /* Any floating arithmetic may trap. */
2479 if (fp_operation
&& flag_trapping_math
)
2487 /* Constructing an object cannot trap. */
2491 /* Any floating arithmetic may trap. */
2492 if (fp_operation
&& flag_trapping_math
)
2500 /* Return true if operation OP may trap. FP_OPERATION is true if OP is applied
2501 on floating-point values. HONOR_TRAPV is true if OP is applied on integer
2502 type operands that may trap. If OP is a division operator, DIVISOR contains
2503 the value of the divisor. */
2506 operation_could_trap_p (enum tree_code op
, bool fp_operation
, bool honor_trapv
,
2509 bool honor_nans
= (fp_operation
&& flag_trapping_math
2510 && !flag_finite_math_only
);
2511 bool honor_snans
= fp_operation
&& flag_signaling_nans
!= 0;
2514 if (TREE_CODE_CLASS (op
) != tcc_comparison
2515 && TREE_CODE_CLASS (op
) != tcc_unary
2516 && TREE_CODE_CLASS (op
) != tcc_binary
2520 return operation_could_trap_helper_p (op
, fp_operation
, honor_trapv
,
2521 honor_nans
, honor_snans
, divisor
,
2526 /* Returns true if it is possible to prove that the index of
2527 an array access REF (an ARRAY_REF expression) falls into the
2531 in_array_bounds_p (tree ref
)
2533 tree idx
= TREE_OPERAND (ref
, 1);
2536 if (TREE_CODE (idx
) != INTEGER_CST
)
2539 min
= array_ref_low_bound (ref
);
2540 max
= array_ref_up_bound (ref
);
2543 || TREE_CODE (min
) != INTEGER_CST
2544 || TREE_CODE (max
) != INTEGER_CST
)
2547 if (tree_int_cst_lt (idx
, min
)
2548 || tree_int_cst_lt (max
, idx
))
2554 /* Returns true if it is possible to prove that the range of
2555 an array access REF (an ARRAY_RANGE_REF expression) falls
2556 into the array bounds. */
2559 range_in_array_bounds_p (tree ref
)
2561 tree domain_type
= TYPE_DOMAIN (TREE_TYPE (ref
));
2562 tree range_min
, range_max
, min
, max
;
2564 range_min
= TYPE_MIN_VALUE (domain_type
);
2565 range_max
= TYPE_MAX_VALUE (domain_type
);
2568 || TREE_CODE (range_min
) != INTEGER_CST
2569 || TREE_CODE (range_max
) != INTEGER_CST
)
2572 min
= array_ref_low_bound (ref
);
2573 max
= array_ref_up_bound (ref
);
2576 || TREE_CODE (min
) != INTEGER_CST
2577 || TREE_CODE (max
) != INTEGER_CST
)
2580 if (tree_int_cst_lt (range_min
, min
)
2581 || tree_int_cst_lt (max
, range_max
))
2587 /* Return true if EXPR can trap, as in dereferencing an invalid pointer
2588 location or floating point arithmetic. C.f. the rtl version, may_trap_p.
2589 This routine expects only GIMPLE lhs or rhs input. */
2592 tree_could_trap_p (tree expr
)
2594 enum tree_code code
;
2595 bool fp_operation
= false;
2596 bool honor_trapv
= false;
2597 tree t
, base
, div
= NULL_TREE
;
2602 code
= TREE_CODE (expr
);
2603 t
= TREE_TYPE (expr
);
2607 if (COMPARISON_CLASS_P (expr
))
2608 fp_operation
= FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr
, 0)));
2610 fp_operation
= FLOAT_TYPE_P (t
);
2611 honor_trapv
= INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
);
2614 if (TREE_CODE_CLASS (code
) == tcc_binary
)
2615 div
= TREE_OPERAND (expr
, 1);
2616 if (operation_could_trap_p (code
, fp_operation
, honor_trapv
, div
))
2626 case VIEW_CONVERT_EXPR
:
2627 case WITH_SIZE_EXPR
:
2628 expr
= TREE_OPERAND (expr
, 0);
2629 code
= TREE_CODE (expr
);
2632 case ARRAY_RANGE_REF
:
2633 base
= TREE_OPERAND (expr
, 0);
2634 if (tree_could_trap_p (base
))
2636 if (TREE_THIS_NOTRAP (expr
))
2638 return !range_in_array_bounds_p (expr
);
2641 base
= TREE_OPERAND (expr
, 0);
2642 if (tree_could_trap_p (base
))
2644 if (TREE_THIS_NOTRAP (expr
))
2646 return !in_array_bounds_p (expr
);
2648 case TARGET_MEM_REF
:
2650 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
2651 && tree_could_trap_p (TREE_OPERAND (TREE_OPERAND (expr
, 0), 0)))
2653 if (TREE_THIS_NOTRAP (expr
))
2655 /* We cannot prove that the access is in-bounds when we have
2656 variable-index TARGET_MEM_REFs. */
2657 if (code
== TARGET_MEM_REF
2658 && (TMR_INDEX (expr
) || TMR_INDEX2 (expr
)))
2660 if (TREE_CODE (TREE_OPERAND (expr
, 0)) == ADDR_EXPR
)
2662 tree base
= TREE_OPERAND (TREE_OPERAND (expr
, 0), 0);
2663 offset_int off
= mem_ref_offset (expr
);
2664 if (wi::neg_p (off
, SIGNED
))
2666 if (TREE_CODE (base
) == STRING_CST
)
2667 return wi::leu_p (TREE_STRING_LENGTH (base
), off
);
2668 else if (DECL_SIZE_UNIT (base
) == NULL_TREE
2669 || TREE_CODE (DECL_SIZE_UNIT (base
)) != INTEGER_CST
2670 || wi::leu_p (wi::to_offset (DECL_SIZE_UNIT (base
)), off
))
2672 /* Now we are sure the first byte of the access is inside
2679 return !TREE_THIS_NOTRAP (expr
);
2682 return TREE_THIS_VOLATILE (expr
);
2685 t
= get_callee_fndecl (expr
);
2686 /* Assume that calls to weak functions may trap. */
2687 if (!t
|| !DECL_P (t
))
2690 return tree_could_trap_p (t
);
2694 /* Assume that accesses to weak functions may trap, unless we know
2695 they are certainly defined in current TU or in some other
2697 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2699 cgraph_node
*node
= cgraph_node::get (expr
);
2701 node
= node
->function_symbol ();
2702 return !(node
&& node
->in_other_partition
);
2707 /* Assume that accesses to weak vars may trap, unless we know
2708 they are certainly defined in current TU or in some other
2710 if (DECL_WEAK (expr
) && !DECL_COMDAT (expr
) && DECL_EXTERNAL (expr
))
2712 varpool_node
*node
= varpool_node::get (expr
);
2714 node
= node
->ultimate_alias_target ();
2715 return !(node
&& node
->in_other_partition
);
2725 /* Helper for stmt_could_throw_p. Return true if STMT (assumed to be a
2726 an assignment or a conditional) may throw. */
2729 stmt_could_throw_1_p (gimple
*stmt
)
2731 enum tree_code code
= gimple_expr_code (stmt
);
2732 bool honor_nans
= false;
2733 bool honor_snans
= false;
2734 bool fp_operation
= false;
2735 bool honor_trapv
= false;
2740 if (TREE_CODE_CLASS (code
) == tcc_comparison
2741 || TREE_CODE_CLASS (code
) == tcc_unary
2742 || TREE_CODE_CLASS (code
) == tcc_binary
2743 || code
== FMA_EXPR
)
2745 if (is_gimple_assign (stmt
)
2746 && TREE_CODE_CLASS (code
) == tcc_comparison
)
2747 t
= TREE_TYPE (gimple_assign_rhs1 (stmt
));
2748 else if (gimple_code (stmt
) == GIMPLE_COND
)
2749 t
= TREE_TYPE (gimple_cond_lhs (stmt
));
2751 t
= gimple_expr_type (stmt
);
2752 fp_operation
= FLOAT_TYPE_P (t
);
2755 honor_nans
= flag_trapping_math
&& !flag_finite_math_only
;
2756 honor_snans
= flag_signaling_nans
!= 0;
2758 else if (INTEGRAL_TYPE_P (t
) && TYPE_OVERFLOW_TRAPS (t
))
2762 /* Check if the main expression may trap. */
2763 t
= is_gimple_assign (stmt
) ? gimple_assign_rhs2 (stmt
) : NULL
;
2764 ret
= operation_could_trap_helper_p (code
, fp_operation
, honor_trapv
,
2765 honor_nans
, honor_snans
, t
,
2770 /* If the expression does not trap, see if any of the individual operands may
2772 for (i
= 0; i
< gimple_num_ops (stmt
); i
++)
2773 if (tree_could_trap_p (gimple_op (stmt
, i
)))
2780 /* Return true if statement STMT could throw an exception. */
2783 stmt_could_throw_p (gimple
*stmt
)
2785 if (!flag_exceptions
)
2788 /* The only statements that can throw an exception are assignments,
2789 conditionals, calls, resx, and asms. */
2790 switch (gimple_code (stmt
))
2796 return !gimple_call_nothrow_p (as_a
<gcall
*> (stmt
));
2800 if (!cfun
->can_throw_non_call_exceptions
)
2802 return stmt_could_throw_1_p (stmt
);
2805 if (!cfun
->can_throw_non_call_exceptions
)
2807 return gimple_asm_volatile_p (as_a
<gasm
*> (stmt
));
2815 /* Return true if expression T could throw an exception. */
2818 tree_could_throw_p (tree t
)
2820 if (!flag_exceptions
)
2822 if (TREE_CODE (t
) == MODIFY_EXPR
)
2824 if (cfun
->can_throw_non_call_exceptions
2825 && tree_could_trap_p (TREE_OPERAND (t
, 0)))
2827 t
= TREE_OPERAND (t
, 1);
2830 if (TREE_CODE (t
) == WITH_SIZE_EXPR
)
2831 t
= TREE_OPERAND (t
, 0);
2832 if (TREE_CODE (t
) == CALL_EXPR
)
2833 return (call_expr_flags (t
) & ECF_NOTHROW
) == 0;
2834 if (cfun
->can_throw_non_call_exceptions
)
2835 return tree_could_trap_p (t
);
2839 /* Return true if STMT can throw an exception that is not caught within
2840 the current function (CFUN). */
2843 stmt_can_throw_external (gimple
*stmt
)
2847 if (!stmt_could_throw_p (stmt
))
2850 lp_nr
= lookup_stmt_eh_lp (stmt
);
2854 /* Return true if STMT can throw an exception that is caught within
2855 the current function (CFUN). */
2858 stmt_can_throw_internal (gimple
*stmt
)
2862 if (!stmt_could_throw_p (stmt
))
2865 lp_nr
= lookup_stmt_eh_lp (stmt
);
2869 /* Given a statement STMT in IFUN, if STMT can no longer throw, then
2870 remove any entry it might have from the EH table. Return true if
2871 any change was made. */
2874 maybe_clean_eh_stmt_fn (struct function
*ifun
, gimple
*stmt
)
2876 if (stmt_could_throw_p (stmt
))
2878 return remove_stmt_from_eh_lp_fn (ifun
, stmt
);
2881 /* Likewise, but always use the current function. */
2884 maybe_clean_eh_stmt (gimple
*stmt
)
2886 return maybe_clean_eh_stmt_fn (cfun
, stmt
);
2889 /* Given a statement OLD_STMT and a new statement NEW_STMT that has replaced
2890 OLD_STMT in the function, remove OLD_STMT from the EH table and put NEW_STMT
2891 in the table if it should be in there. Return TRUE if a replacement was
2892 done that my require an EH edge purge. */
2895 maybe_clean_or_replace_eh_stmt (gimple
*old_stmt
, gimple
*new_stmt
)
2897 int lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2901 bool new_stmt_could_throw
= stmt_could_throw_p (new_stmt
);
2903 if (new_stmt
== old_stmt
&& new_stmt_could_throw
)
2906 remove_stmt_from_eh_lp (old_stmt
);
2907 if (new_stmt_could_throw
)
2909 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2919 /* Given a statement OLD_STMT in OLD_FUN and a duplicate statement NEW_STMT
2920 in NEW_FUN, copy the EH table data from OLD_STMT to NEW_STMT. The MAP
2921 operand is the return value of duplicate_eh_regions. */
2924 maybe_duplicate_eh_stmt_fn (struct function
*new_fun
, gimple
*new_stmt
,
2925 struct function
*old_fun
, gimple
*old_stmt
,
2926 hash_map
<void *, void *> *map
,
2929 int old_lp_nr
, new_lp_nr
;
2931 if (!stmt_could_throw_p (new_stmt
))
2934 old_lp_nr
= lookup_stmt_eh_lp_fn (old_fun
, old_stmt
);
2937 if (default_lp_nr
== 0)
2939 new_lp_nr
= default_lp_nr
;
2941 else if (old_lp_nr
> 0)
2943 eh_landing_pad old_lp
, new_lp
;
2945 old_lp
= (*old_fun
->eh
->lp_array
)[old_lp_nr
];
2946 new_lp
= static_cast<eh_landing_pad
> (*map
->get (old_lp
));
2947 new_lp_nr
= new_lp
->index
;
2951 eh_region old_r
, new_r
;
2953 old_r
= (*old_fun
->eh
->region_array
)[-old_lp_nr
];
2954 new_r
= static_cast<eh_region
> (*map
->get (old_r
));
2955 new_lp_nr
= -new_r
->index
;
2958 add_stmt_to_eh_lp_fn (new_fun
, new_stmt
, new_lp_nr
);
2962 /* Similar, but both OLD_STMT and NEW_STMT are within the current function,
2963 and thus no remapping is required. */
2966 maybe_duplicate_eh_stmt (gimple
*new_stmt
, gimple
*old_stmt
)
2970 if (!stmt_could_throw_p (new_stmt
))
2973 lp_nr
= lookup_stmt_eh_lp (old_stmt
);
2977 add_stmt_to_eh_lp (new_stmt
, lp_nr
);
2981 /* Returns TRUE if oneh and twoh are exception handlers (gimple_try_cleanup of
2982 GIMPLE_TRY) that are similar enough to be considered the same. Currently
2983 this only handles handlers consisting of a single call, as that's the
2984 important case for C++: a destructor call for a particular object showing
2985 up in multiple handlers. */
2988 same_handler_p (gimple_seq oneh
, gimple_seq twoh
)
2990 gimple_stmt_iterator gsi
;
2991 gimple
*ones
, *twos
;
2994 gsi
= gsi_start (oneh
);
2995 if (!gsi_one_before_end_p (gsi
))
2997 ones
= gsi_stmt (gsi
);
2999 gsi
= gsi_start (twoh
);
3000 if (!gsi_one_before_end_p (gsi
))
3002 twos
= gsi_stmt (gsi
);
3004 if (!is_gimple_call (ones
)
3005 || !is_gimple_call (twos
)
3006 || gimple_call_lhs (ones
)
3007 || gimple_call_lhs (twos
)
3008 || gimple_call_chain (ones
)
3009 || gimple_call_chain (twos
)
3010 || !gimple_call_same_target_p (ones
, twos
)
3011 || gimple_call_num_args (ones
) != gimple_call_num_args (twos
))
3014 for (ai
= 0; ai
< gimple_call_num_args (ones
); ++ai
)
3015 if (!operand_equal_p (gimple_call_arg (ones
, ai
),
3016 gimple_call_arg (twos
, ai
), 0))
3023 try { A() } finally { try { ~B() } catch { ~A() } }
3024 try { ... } finally { ~A() }
3026 try { A() } catch { ~B() }
3027 try { ~B() ... } finally { ~A() }
3029 This occurs frequently in C++, where A is a local variable and B is a
3030 temporary used in the initializer for A. */
3033 optimize_double_finally (gtry
*one
, gtry
*two
)
3036 gimple_stmt_iterator gsi
;
3039 cleanup
= gimple_try_cleanup (one
);
3040 gsi
= gsi_start (cleanup
);
3041 if (!gsi_one_before_end_p (gsi
))
3044 oneh
= gsi_stmt (gsi
);
3045 if (gimple_code (oneh
) != GIMPLE_TRY
3046 || gimple_try_kind (oneh
) != GIMPLE_TRY_CATCH
)
3049 if (same_handler_p (gimple_try_cleanup (oneh
), gimple_try_cleanup (two
)))
3051 gimple_seq seq
= gimple_try_eval (oneh
);
3053 gimple_try_set_cleanup (one
, seq
);
3054 gimple_try_set_kind (one
, GIMPLE_TRY_CATCH
);
3055 seq
= copy_gimple_seq_and_replace_locals (seq
);
3056 gimple_seq_add_seq (&seq
, gimple_try_eval (two
));
3057 gimple_try_set_eval (two
, seq
);
3061 /* Perform EH refactoring optimizations that are simpler to do when code
3062 flow has been lowered but EH structures haven't. */
3065 refactor_eh_r (gimple_seq seq
)
3067 gimple_stmt_iterator gsi
;
3072 gsi
= gsi_start (seq
);
3076 if (gsi_end_p (gsi
))
3079 two
= gsi_stmt (gsi
);
3081 if (gtry
*try_one
= dyn_cast
<gtry
*> (one
))
3082 if (gtry
*try_two
= dyn_cast
<gtry
*> (two
))
3083 if (gimple_try_kind (try_one
) == GIMPLE_TRY_FINALLY
3084 && gimple_try_kind (try_two
) == GIMPLE_TRY_FINALLY
)
3085 optimize_double_finally (try_one
, try_two
);
3087 switch (gimple_code (one
))
3090 refactor_eh_r (gimple_try_eval (one
));
3091 refactor_eh_r (gimple_try_cleanup (one
));
3094 refactor_eh_r (gimple_catch_handler (as_a
<gcatch
*> (one
)));
3096 case GIMPLE_EH_FILTER
:
3097 refactor_eh_r (gimple_eh_filter_failure (one
));
3099 case GIMPLE_EH_ELSE
:
3101 geh_else
*eh_else_stmt
= as_a
<geh_else
*> (one
);
3102 refactor_eh_r (gimple_eh_else_n_body (eh_else_stmt
));
3103 refactor_eh_r (gimple_eh_else_e_body (eh_else_stmt
));
3118 const pass_data pass_data_refactor_eh
=
3120 GIMPLE_PASS
, /* type */
3122 OPTGROUP_NONE
, /* optinfo_flags */
3123 TV_TREE_EH
, /* tv_id */
3124 PROP_gimple_lcf
, /* properties_required */
3125 0, /* properties_provided */
3126 0, /* properties_destroyed */
3127 0, /* todo_flags_start */
3128 0, /* todo_flags_finish */
3131 class pass_refactor_eh
: public gimple_opt_pass
3134 pass_refactor_eh (gcc::context
*ctxt
)
3135 : gimple_opt_pass (pass_data_refactor_eh
, ctxt
)
3138 /* opt_pass methods: */
3139 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3140 virtual unsigned int execute (function
*)
3142 refactor_eh_r (gimple_body (current_function_decl
));
3146 }; // class pass_refactor_eh
3151 make_pass_refactor_eh (gcc::context
*ctxt
)
3153 return new pass_refactor_eh (ctxt
);
3156 /* At the end of gimple optimization, we can lower RESX. */
3159 lower_resx (basic_block bb
, gresx
*stmt
,
3160 hash_map
<eh_region
, tree
> *mnt_map
)
3163 eh_region src_r
, dst_r
;
3164 gimple_stmt_iterator gsi
;
3169 lp_nr
= lookup_stmt_eh_lp (stmt
);
3171 dst_r
= get_eh_region_from_lp_number (lp_nr
);
3175 src_r
= get_eh_region_from_number (gimple_resx_region (stmt
));
3176 gsi
= gsi_last_bb (bb
);
3180 /* We can wind up with no source region when pass_cleanup_eh shows
3181 that there are no entries into an eh region and deletes it, but
3182 then the block that contains the resx isn't removed. This can
3183 happen without optimization when the switch statement created by
3184 lower_try_finally_switch isn't simplified to remove the eh case.
3186 Resolve this by expanding the resx node to an abort. */
3188 fn
= builtin_decl_implicit (BUILT_IN_TRAP
);
3189 x
= gimple_build_call (fn
, 0);
3190 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3192 while (EDGE_COUNT (bb
->succs
) > 0)
3193 remove_edge (EDGE_SUCC (bb
, 0));
3197 /* When we have a destination region, we resolve this by copying
3198 the excptr and filter values into place, and changing the edge
3199 to immediately after the landing pad. */
3207 /* We are resuming into a MUST_NOT_CALL region. Expand a call to
3208 the failure decl into a new block, if needed. */
3209 gcc_assert (dst_r
->type
== ERT_MUST_NOT_THROW
);
3211 tree
*slot
= mnt_map
->get (dst_r
);
3214 gimple_stmt_iterator gsi2
;
3216 new_bb
= create_empty_bb (bb
);
3217 add_bb_to_loop (new_bb
, bb
->loop_father
);
3218 lab
= gimple_block_label (new_bb
);
3219 gsi2
= gsi_start_bb (new_bb
);
3221 fn
= dst_r
->u
.must_not_throw
.failure_decl
;
3222 x
= gimple_build_call (fn
, 0);
3223 gimple_set_location (x
, dst_r
->u
.must_not_throw
.failure_loc
);
3224 gsi_insert_after (&gsi2
, x
, GSI_CONTINUE_LINKING
);
3226 mnt_map
->put (dst_r
, lab
);
3231 new_bb
= label_to_block (lab
);
3234 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3235 e
= make_edge (bb
, new_bb
, EDGE_FALLTHRU
);
3236 e
->count
= bb
->count
;
3237 e
->probability
= REG_BR_PROB_BASE
;
3242 tree dst_nr
= build_int_cst (integer_type_node
, dst_r
->index
);
3244 fn
= builtin_decl_implicit (BUILT_IN_EH_COPY_VALUES
);
3245 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3246 x
= gimple_build_call (fn
, 2, dst_nr
, src_nr
);
3247 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3249 /* Update the flags for the outgoing edge. */
3250 e
= single_succ_edge (bb
);
3251 gcc_assert (e
->flags
& EDGE_EH
);
3252 e
->flags
= (e
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
3253 e
->probability
= REG_BR_PROB_BASE
;
3254 e
->count
= bb
->count
;
3256 /* If there are no more EH users of the landing pad, delete it. */
3257 FOR_EACH_EDGE (e
, ei
, e
->dest
->preds
)
3258 if (e
->flags
& EDGE_EH
)
3262 eh_landing_pad lp
= get_eh_landing_pad_from_number (lp_nr
);
3263 remove_eh_landing_pad (lp
);
3273 /* When we don't have a destination region, this exception escapes
3274 up the call chain. We resolve this by generating a call to the
3275 _Unwind_Resume library function. */
3277 /* The ARM EABI redefines _Unwind_Resume as __cxa_end_cleanup
3278 with no arguments for C++ and Java. Check for that. */
3279 if (src_r
->use_cxa_end_cleanup
)
3281 fn
= builtin_decl_implicit (BUILT_IN_CXA_END_CLEANUP
);
3282 x
= gimple_build_call (fn
, 0);
3283 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3287 fn
= builtin_decl_implicit (BUILT_IN_EH_POINTER
);
3288 src_nr
= build_int_cst (integer_type_node
, src_r
->index
);
3289 x
= gimple_build_call (fn
, 1, src_nr
);
3290 var
= create_tmp_var (ptr_type_node
);
3291 var
= make_ssa_name (var
, x
);
3292 gimple_call_set_lhs (x
, var
);
3293 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3295 fn
= builtin_decl_implicit (BUILT_IN_UNWIND_RESUME
);
3296 x
= gimple_build_call (fn
, 1, var
);
3297 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3300 gcc_assert (EDGE_COUNT (bb
->succs
) == 0);
3303 gsi_remove (&gsi
, true);
3310 const pass_data pass_data_lower_resx
=
3312 GIMPLE_PASS
, /* type */
3314 OPTGROUP_NONE
, /* optinfo_flags */
3315 TV_TREE_EH
, /* tv_id */
3316 PROP_gimple_lcf
, /* properties_required */
3317 0, /* properties_provided */
3318 0, /* properties_destroyed */
3319 0, /* todo_flags_start */
3320 0, /* todo_flags_finish */
3323 class pass_lower_resx
: public gimple_opt_pass
3326 pass_lower_resx (gcc::context
*ctxt
)
3327 : gimple_opt_pass (pass_data_lower_resx
, ctxt
)
3330 /* opt_pass methods: */
3331 virtual bool gate (function
*) { return flag_exceptions
!= 0; }
3332 virtual unsigned int execute (function
*);
3334 }; // class pass_lower_resx
3337 pass_lower_resx::execute (function
*fun
)
3340 bool dominance_invalidated
= false;
3341 bool any_rewritten
= false;
3343 hash_map
<eh_region
, tree
> mnt_map
;
3345 FOR_EACH_BB_FN (bb
, fun
)
3347 gimple
*last
= last_stmt (bb
);
3348 if (last
&& is_gimple_resx (last
))
3350 dominance_invalidated
|=
3351 lower_resx (bb
, as_a
<gresx
*> (last
), &mnt_map
);
3352 any_rewritten
= true;
3356 if (dominance_invalidated
)
3358 free_dominance_info (CDI_DOMINATORS
);
3359 free_dominance_info (CDI_POST_DOMINATORS
);
3362 return any_rewritten
? TODO_update_ssa_only_virtuals
: 0;
3368 make_pass_lower_resx (gcc::context
*ctxt
)
3370 return new pass_lower_resx (ctxt
);
3373 /* Try to optimize var = {v} {CLOBBER} stmts followed just by
3377 optimize_clobbers (basic_block bb
)
3379 gimple_stmt_iterator gsi
= gsi_last_bb (bb
);
3380 bool any_clobbers
= false;
3381 bool seen_stack_restore
= false;
3385 /* Only optimize anything if the bb contains at least one clobber,
3386 ends with resx (checked by caller), optionally contains some
3387 debug stmts or labels, or at most one __builtin_stack_restore
3388 call, and has an incoming EH edge. */
3389 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3391 gimple
*stmt
= gsi_stmt (gsi
);
3392 if (is_gimple_debug (stmt
))
3394 if (gimple_clobber_p (stmt
))
3396 any_clobbers
= true;
3399 if (!seen_stack_restore
3400 && gimple_call_builtin_p (stmt
, BUILT_IN_STACK_RESTORE
))
3402 seen_stack_restore
= true;
3405 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3411 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3412 if (e
->flags
& EDGE_EH
)
3416 gsi
= gsi_last_bb (bb
);
3417 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3419 gimple
*stmt
= gsi_stmt (gsi
);
3420 if (!gimple_clobber_p (stmt
))
3422 unlink_stmt_vdef (stmt
);
3423 gsi_remove (&gsi
, true);
3424 release_defs (stmt
);
3428 /* Try to sink var = {v} {CLOBBER} stmts followed just by
3429 internal throw to successor BB. */
3432 sink_clobbers (basic_block bb
)
3436 gimple_stmt_iterator gsi
, dgsi
;
3438 bool any_clobbers
= false;
3441 /* Only optimize if BB has a single EH successor and
3442 all predecessor edges are EH too. */
3443 if (!single_succ_p (bb
)
3444 || (single_succ_edge (bb
)->flags
& EDGE_EH
) == 0)
3447 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
3449 if ((e
->flags
& EDGE_EH
) == 0)
3453 /* And BB contains only CLOBBER stmts before the final
3455 gsi
= gsi_last_bb (bb
);
3456 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3458 gimple
*stmt
= gsi_stmt (gsi
);
3459 if (is_gimple_debug (stmt
))
3461 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3463 if (!gimple_clobber_p (stmt
))
3465 any_clobbers
= true;
3470 edge succe
= single_succ_edge (bb
);
3471 succbb
= succe
->dest
;
3473 /* See if there is a virtual PHI node to take an updated virtual
3476 tree vuse
= NULL_TREE
;
3477 for (gphi_iterator gpi
= gsi_start_phis (succbb
);
3478 !gsi_end_p (gpi
); gsi_next (&gpi
))
3480 tree res
= gimple_phi_result (gpi
.phi ());
3481 if (virtual_operand_p (res
))
3489 dgsi
= gsi_after_labels (succbb
);
3490 gsi
= gsi_last_bb (bb
);
3491 for (gsi_prev (&gsi
); !gsi_end_p (gsi
); gsi_prev (&gsi
))
3493 gimple
*stmt
= gsi_stmt (gsi
);
3495 if (is_gimple_debug (stmt
))
3497 if (gimple_code (stmt
) == GIMPLE_LABEL
)
3499 lhs
= gimple_assign_lhs (stmt
);
3500 /* Unfortunately we don't have dominance info updated at this
3501 point, so checking if
3502 dominated_by_p (CDI_DOMINATORS, succbb,
3503 gimple_bb (SSA_NAME_DEF_STMT (TREE_OPERAND (lhs, 0)))
3504 would be too costly. Thus, avoid sinking any clobbers that
3505 refer to non-(D) SSA_NAMEs. */
3506 if (TREE_CODE (lhs
) == MEM_REF
3507 && TREE_CODE (TREE_OPERAND (lhs
, 0)) == SSA_NAME
3508 && !SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs
, 0)))
3510 unlink_stmt_vdef (stmt
);
3511 gsi_remove (&gsi
, true);
3512 release_defs (stmt
);
3516 /* As we do not change stmt order when sinking across a
3517 forwarder edge we can keep virtual operands in place. */
3518 gsi_remove (&gsi
, false);
3519 gsi_insert_before (&dgsi
, stmt
, GSI_NEW_STMT
);
3521 /* But adjust virtual operands if we sunk across a PHI node. */
3525 imm_use_iterator iter
;
3526 use_operand_p use_p
;
3527 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, vuse
)
3528 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
3529 SET_USE (use_p
, gimple_vdef (stmt
));
3530 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
))
3532 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (gimple_vdef (stmt
)) = 1;
3533 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse
) = 0;
3535 /* Adjust the incoming virtual operand. */
3536 SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (vphi
, succe
), gimple_vuse (stmt
));
3537 SET_USE (gimple_vuse_op (stmt
), vuse
);
3539 /* If there isn't a single predecessor but no virtual PHI node
3540 arrange for virtual operands to be renamed. */
3541 else if (gimple_vuse_op (stmt
) != NULL_USE_OPERAND_P
3542 && !single_pred_p (succbb
))
3544 /* In this case there will be no use of the VDEF of this stmt.
3545 ??? Unless this is a secondary opportunity and we have not
3546 removed unreachable blocks yet, so we cannot assert this.
3547 Which also means we will end up renaming too many times. */
3548 SET_USE (gimple_vuse_op (stmt
), gimple_vop (cfun
));
3549 mark_virtual_operands_for_renaming (cfun
);
3550 todo
|= TODO_update_ssa_only_virtuals
;
3557 /* At the end of inlining, we can lower EH_DISPATCH. Return true when
3558 we have found some duplicate labels and removed some edges. */
3561 lower_eh_dispatch (basic_block src
, geh_dispatch
*stmt
)
3563 gimple_stmt_iterator gsi
;
3568 bool redirected
= false;
3570 region_nr
= gimple_eh_dispatch_region (stmt
);
3571 r
= get_eh_region_from_number (region_nr
);
3573 gsi
= gsi_last_bb (src
);
3579 auto_vec
<tree
> labels
;
3580 tree default_label
= NULL
;
3584 hash_set
<tree
> seen_values
;
3586 /* Collect the labels for a switch. Zero the post_landing_pad
3587 field becase we'll no longer have anything keeping these labels
3588 in existence and the optimizer will be free to merge these
3590 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
3592 tree tp_node
, flt_node
, lab
= c
->label
;
3593 bool have_label
= false;
3596 tp_node
= c
->type_list
;
3597 flt_node
= c
->filter_list
;
3599 if (tp_node
== NULL
)
3601 default_label
= lab
;
3606 /* Filter out duplicate labels that arise when this handler
3607 is shadowed by an earlier one. When no labels are
3608 attached to the handler anymore, we remove
3609 the corresponding edge and then we delete unreachable
3610 blocks at the end of this pass. */
3611 if (! seen_values
.contains (TREE_VALUE (flt_node
)))
3613 tree t
= build_case_label (TREE_VALUE (flt_node
),
3615 labels
.safe_push (t
);
3616 seen_values
.add (TREE_VALUE (flt_node
));
3620 tp_node
= TREE_CHAIN (tp_node
);
3621 flt_node
= TREE_CHAIN (flt_node
);
3626 remove_edge (find_edge (src
, label_to_block (lab
)));
3631 /* Clean up the edge flags. */
3632 FOR_EACH_EDGE (e
, ei
, src
->succs
)
3634 if (e
->flags
& EDGE_FALLTHRU
)
3636 /* If there was no catch-all, use the fallthru edge. */
3637 if (default_label
== NULL
)
3638 default_label
= gimple_block_label (e
->dest
);
3639 e
->flags
&= ~EDGE_FALLTHRU
;
3642 gcc_assert (default_label
!= NULL
);
3644 /* Don't generate a switch if there's only a default case.
3645 This is common in the form of try { A; } catch (...) { B; }. */
3646 if (!labels
.exists ())
3648 e
= single_succ_edge (src
);
3649 e
->flags
|= EDGE_FALLTHRU
;
3653 fn
= builtin_decl_implicit (BUILT_IN_EH_FILTER
);
3654 x
= gimple_build_call (fn
, 1, build_int_cst (integer_type_node
,
3656 filter
= create_tmp_var (TREE_TYPE (TREE_TYPE (fn
)));
3657 filter
= make_ssa_name (filter
, x
);
3658 gimple_call_set_lhs (x
, filter
);
3659 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3661 /* Turn the default label into a default case. */
3662 default_label
= build_case_label (NULL
, NULL
, default_label
);
3663 sort_case_labels (labels
);
3665 x
= gimple_build_switch (filter
, default_label
, labels
);
3666 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3671 case ERT_ALLOWED_EXCEPTIONS
:
3673 edge b_e
= BRANCH_EDGE (src
);
3674 edge f_e
= FALLTHRU_EDGE (src
);
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 r
->u
.allowed
.label
= NULL
;
3685 x
= gimple_build_cond (EQ_EXPR
, filter
,
3686 build_int_cst (TREE_TYPE (filter
),
3687 r
->u
.allowed
.filter
),
3688 NULL_TREE
, NULL_TREE
);
3689 gsi_insert_before (&gsi
, x
, GSI_SAME_STMT
);
3691 b_e
->flags
= b_e
->flags
| EDGE_TRUE_VALUE
;
3692 f_e
->flags
= (f_e
->flags
& ~EDGE_FALLTHRU
) | EDGE_FALSE_VALUE
;
3700 /* Replace the EH_DISPATCH with the SWITCH or COND generated above. */
3701 gsi_remove (&gsi
, true);
3707 const pass_data pass_data_lower_eh_dispatch
=
3709 GIMPLE_PASS
, /* type */
3710 "ehdisp", /* name */
3711 OPTGROUP_NONE
, /* optinfo_flags */
3712 TV_TREE_EH
, /* tv_id */
3713 PROP_gimple_lcf
, /* properties_required */
3714 0, /* properties_provided */
3715 0, /* properties_destroyed */
3716 0, /* todo_flags_start */
3717 0, /* todo_flags_finish */
3720 class pass_lower_eh_dispatch
: public gimple_opt_pass
3723 pass_lower_eh_dispatch (gcc::context
*ctxt
)
3724 : gimple_opt_pass (pass_data_lower_eh_dispatch
, ctxt
)
3727 /* opt_pass methods: */
3728 virtual bool gate (function
*fun
) { return fun
->eh
->region_tree
!= NULL
; }
3729 virtual unsigned int execute (function
*);
3731 }; // class pass_lower_eh_dispatch
3734 pass_lower_eh_dispatch::execute (function
*fun
)
3738 bool redirected
= false;
3740 assign_filter_values ();
3742 FOR_EACH_BB_FN (bb
, fun
)
3744 gimple
*last
= last_stmt (bb
);
3747 if (gimple_code (last
) == GIMPLE_EH_DISPATCH
)
3749 redirected
|= lower_eh_dispatch (bb
,
3750 as_a
<geh_dispatch
*> (last
));
3751 flags
|= TODO_update_ssa_only_virtuals
;
3753 else if (gimple_code (last
) == GIMPLE_RESX
)
3755 if (stmt_can_throw_external (last
))
3756 optimize_clobbers (bb
);
3758 flags
|= sink_clobbers (bb
);
3763 delete_unreachable_blocks ();
3770 make_pass_lower_eh_dispatch (gcc::context
*ctxt
)
3772 return new pass_lower_eh_dispatch (ctxt
);
3775 /* Walk statements, see what regions and, optionally, landing pads
3776 are really referenced.
3778 Returns in R_REACHABLEP an sbitmap with bits set for reachable regions,
3779 and in LP_REACHABLE an sbitmap with bits set for reachable landing pads.
3781 Passing NULL for LP_REACHABLE is valid, in this case only reachable
3784 The caller is responsible for freeing the returned sbitmaps. */
3787 mark_reachable_handlers (sbitmap
*r_reachablep
, sbitmap
*lp_reachablep
)
3789 sbitmap r_reachable
, lp_reachable
;
3791 bool mark_landing_pads
= (lp_reachablep
!= NULL
);
3792 gcc_checking_assert (r_reachablep
!= NULL
);
3794 r_reachable
= sbitmap_alloc (cfun
->eh
->region_array
->length ());
3795 bitmap_clear (r_reachable
);
3796 *r_reachablep
= r_reachable
;
3798 if (mark_landing_pads
)
3800 lp_reachable
= sbitmap_alloc (cfun
->eh
->lp_array
->length ());
3801 bitmap_clear (lp_reachable
);
3802 *lp_reachablep
= lp_reachable
;
3805 lp_reachable
= NULL
;
3807 FOR_EACH_BB_FN (bb
, cfun
)
3809 gimple_stmt_iterator gsi
;
3811 for (gsi
= gsi_start_bb (bb
); !gsi_end_p (gsi
); gsi_next (&gsi
))
3813 gimple
*stmt
= gsi_stmt (gsi
);
3815 if (mark_landing_pads
)
3817 int lp_nr
= lookup_stmt_eh_lp (stmt
);
3819 /* Negative LP numbers are MUST_NOT_THROW regions which
3820 are not considered BB enders. */
3822 bitmap_set_bit (r_reachable
, -lp_nr
);
3824 /* Positive LP numbers are real landing pads, and BB enders. */
3827 gcc_assert (gsi_one_before_end_p (gsi
));
3828 eh_region region
= get_eh_region_from_lp_number (lp_nr
);
3829 bitmap_set_bit (r_reachable
, region
->index
);
3830 bitmap_set_bit (lp_reachable
, lp_nr
);
3834 /* Avoid removing regions referenced from RESX/EH_DISPATCH. */
3835 switch (gimple_code (stmt
))
3838 bitmap_set_bit (r_reachable
,
3839 gimple_resx_region (as_a
<gresx
*> (stmt
)));
3841 case GIMPLE_EH_DISPATCH
:
3842 bitmap_set_bit (r_reachable
,
3843 gimple_eh_dispatch_region (
3844 as_a
<geh_dispatch
*> (stmt
)));
3847 if (gimple_call_builtin_p (stmt
, BUILT_IN_EH_COPY_VALUES
))
3848 for (int i
= 0; i
< 2; ++i
)
3850 tree rt
= gimple_call_arg (stmt
, i
);
3851 HOST_WIDE_INT ri
= tree_to_shwi (rt
);
3853 gcc_assert (ri
== (int)ri
);
3854 bitmap_set_bit (r_reachable
, ri
);
3864 /* Remove unreachable handlers and unreachable landing pads. */
3867 remove_unreachable_handlers (void)
3869 sbitmap r_reachable
, lp_reachable
;
3874 mark_reachable_handlers (&r_reachable
, &lp_reachable
);
3878 fprintf (dump_file
, "Before removal of unreachable regions:\n");
3879 dump_eh_tree (dump_file
, cfun
);
3880 fprintf (dump_file
, "Reachable regions: ");
3881 dump_bitmap_file (dump_file
, r_reachable
);
3882 fprintf (dump_file
, "Reachable landing pads: ");
3883 dump_bitmap_file (dump_file
, lp_reachable
);
3888 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3889 if (region
&& !bitmap_bit_p (r_reachable
, region
->index
))
3891 "Removing unreachable region %d\n",
3895 remove_unreachable_eh_regions (r_reachable
);
3897 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3898 if (lp
&& !bitmap_bit_p (lp_reachable
, lp
->index
))
3902 "Removing unreachable landing pad %d\n",
3904 remove_eh_landing_pad (lp
);
3909 fprintf (dump_file
, "\n\nAfter removal of unreachable regions:\n");
3910 dump_eh_tree (dump_file
, cfun
);
3911 fprintf (dump_file
, "\n\n");
3914 sbitmap_free (r_reachable
);
3915 sbitmap_free (lp_reachable
);
3918 verify_eh_tree (cfun
);
3921 /* Remove unreachable handlers if any landing pads have been removed after
3922 last ehcleanup pass (due to gimple_purge_dead_eh_edges). */
3925 maybe_remove_unreachable_handlers (void)
3930 if (cfun
->eh
== NULL
)
3933 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->lp_array
, i
, lp
)
3934 if (lp
&& lp
->post_landing_pad
)
3936 if (label_to_block (lp
->post_landing_pad
) == NULL
)
3938 remove_unreachable_handlers ();
3944 /* Remove regions that do not have landing pads. This assumes
3945 that remove_unreachable_handlers has already been run, and
3946 that we've just manipulated the landing pads since then.
3948 Preserve regions with landing pads and regions that prevent
3949 exceptions from propagating further, even if these regions
3950 are not reachable. */
3953 remove_unreachable_handlers_no_lp (void)
3956 sbitmap r_reachable
;
3959 mark_reachable_handlers (&r_reachable
, /*lp_reachablep=*/NULL
);
3961 FOR_EACH_VEC_SAFE_ELT (cfun
->eh
->region_array
, i
, region
)
3966 if (region
->landing_pads
!= NULL
3967 || region
->type
== ERT_MUST_NOT_THROW
)
3968 bitmap_set_bit (r_reachable
, region
->index
);
3971 && !bitmap_bit_p (r_reachable
, region
->index
))
3973 "Removing unreachable region %d\n",
3977 remove_unreachable_eh_regions (r_reachable
);
3979 sbitmap_free (r_reachable
);
3982 /* Undo critical edge splitting on an EH landing pad. Earlier, we
3983 optimisticaly split all sorts of edges, including EH edges. The
3984 optimization passes in between may not have needed them; if not,
3985 we should undo the split.
3987 Recognize this case by having one EH edge incoming to the BB and
3988 one normal edge outgoing; BB should be empty apart from the
3989 post_landing_pad label.
3991 Note that this is slightly different from the empty handler case
3992 handled by cleanup_empty_eh, in that the actual handler may yet
3993 have actual code but the landing pad has been separated from the
3994 handler. As such, cleanup_empty_eh relies on this transformation
3995 having been done first. */
3998 unsplit_eh (eh_landing_pad lp
)
4000 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4001 gimple_stmt_iterator gsi
;
4004 /* Quickly check the edge counts on BB for singularity. */
4005 if (!single_pred_p (bb
) || !single_succ_p (bb
))
4007 e_in
= single_pred_edge (bb
);
4008 e_out
= single_succ_edge (bb
);
4010 /* Input edge must be EH and output edge must be normal. */
4011 if ((e_in
->flags
& EDGE_EH
) == 0 || (e_out
->flags
& EDGE_EH
) != 0)
4014 /* The block must be empty except for the labels and debug insns. */
4015 gsi
= gsi_after_labels (bb
);
4016 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4017 gsi_next_nondebug (&gsi
);
4018 if (!gsi_end_p (gsi
))
4021 /* The destination block must not already have a landing pad
4022 for a different region. */
4023 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4025 glabel
*label_stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4031 lab
= gimple_label_label (label_stmt
);
4032 lp_nr
= EH_LANDING_PAD_NR (lab
);
4033 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4037 /* The new destination block must not already be a destination of
4038 the source block, lest we merge fallthru and eh edges and get
4039 all sorts of confused. */
4040 if (find_edge (e_in
->src
, e_out
->dest
))
4043 /* ??? We can get degenerate phis due to cfg cleanups. I would have
4044 thought this should have been cleaned up by a phicprop pass, but
4045 that doesn't appear to handle virtuals. Propagate by hand. */
4046 if (!gimple_seq_empty_p (phi_nodes (bb
)))
4048 for (gphi_iterator gpi
= gsi_start_phis (bb
); !gsi_end_p (gpi
); )
4051 gphi
*phi
= gpi
.phi ();
4052 tree lhs
= gimple_phi_result (phi
);
4053 tree rhs
= gimple_phi_arg_def (phi
, 0);
4054 use_operand_p use_p
;
4055 imm_use_iterator iter
;
4057 FOR_EACH_IMM_USE_STMT (use_stmt
, iter
, lhs
)
4059 FOR_EACH_IMM_USE_ON_STMT (use_p
, iter
)
4060 SET_USE (use_p
, rhs
);
4063 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs
))
4064 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs
) = 1;
4066 remove_phi_node (&gpi
, true);
4070 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4071 fprintf (dump_file
, "Unsplit EH landing pad %d to block %i.\n",
4072 lp
->index
, e_out
->dest
->index
);
4074 /* Redirect the edge. Since redirect_eh_edge_1 expects to be moving
4075 a successor edge, humor it. But do the real CFG change with the
4076 predecessor of E_OUT in order to preserve the ordering of arguments
4077 to the PHI nodes in E_OUT->DEST. */
4078 redirect_eh_edge_1 (e_in
, e_out
->dest
, false);
4079 redirect_edge_pred (e_out
, e_in
->src
);
4080 e_out
->flags
= e_in
->flags
;
4081 e_out
->probability
= e_in
->probability
;
4082 e_out
->count
= e_in
->count
;
4088 /* Examine each landing pad block and see if it matches unsplit_eh. */
4091 unsplit_all_eh (void)
4093 bool changed
= false;
4097 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4099 changed
|= unsplit_eh (lp
);
4104 /* A subroutine of cleanup_empty_eh. Redirect all EH edges incoming
4105 to OLD_BB to NEW_BB; return true on success, false on failure.
4107 OLD_BB_OUT is the edge into NEW_BB from OLD_BB, so if we miss any
4108 PHI variables from OLD_BB we can pick them up from OLD_BB_OUT.
4109 Virtual PHIs may be deleted and marked for renaming. */
4112 cleanup_empty_eh_merge_phis (basic_block new_bb
, basic_block old_bb
,
4113 edge old_bb_out
, bool change_region
)
4115 gphi_iterator ngsi
, ogsi
;
4118 bitmap ophi_handled
;
4120 /* The destination block must not be a regular successor for any
4121 of the preds of the landing pad. Thus, avoid turning
4131 which CFG verification would choke on. See PR45172 and PR51089. */
4132 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4133 if (find_edge (e
->src
, new_bb
))
4136 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4137 redirect_edge_var_map_clear (e
);
4139 ophi_handled
= BITMAP_ALLOC (NULL
);
4141 /* First, iterate through the PHIs on NEW_BB and set up the edge_var_map
4142 for the edges we're going to move. */
4143 for (ngsi
= gsi_start_phis (new_bb
); !gsi_end_p (ngsi
); gsi_next (&ngsi
))
4145 gphi
*ophi
, *nphi
= ngsi
.phi ();
4148 nresult
= gimple_phi_result (nphi
);
4149 nop
= gimple_phi_arg_def (nphi
, old_bb_out
->dest_idx
);
4151 /* Find the corresponding PHI in OLD_BB so we can forward-propagate
4152 the source ssa_name. */
4154 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4157 if (gimple_phi_result (ophi
) == nop
)
4162 /* If we did find the corresponding PHI, copy those inputs. */
4165 /* If NOP is used somewhere else beyond phis in new_bb, give up. */
4166 if (!has_single_use (nop
))
4168 imm_use_iterator imm_iter
;
4169 use_operand_p use_p
;
4171 FOR_EACH_IMM_USE_FAST (use_p
, imm_iter
, nop
)
4173 if (!gimple_debug_bind_p (USE_STMT (use_p
))
4174 && (gimple_code (USE_STMT (use_p
)) != GIMPLE_PHI
4175 || gimple_bb (USE_STMT (use_p
)) != new_bb
))
4179 bitmap_set_bit (ophi_handled
, SSA_NAME_VERSION (nop
));
4180 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4185 if ((e
->flags
& EDGE_EH
) == 0)
4187 oop
= gimple_phi_arg_def (ophi
, e
->dest_idx
);
4188 oloc
= gimple_phi_arg_location (ophi
, e
->dest_idx
);
4189 redirect_edge_var_map_add (e
, nresult
, oop
, oloc
);
4192 /* If we didn't find the PHI, if it's a real variable or a VOP, we know
4193 from the fact that OLD_BB is tree_empty_eh_handler_p that the
4194 variable is unchanged from input to the block and we can simply
4195 re-use the input to NEW_BB from the OLD_BB_OUT edge. */
4199 = gimple_phi_arg_location (nphi
, old_bb_out
->dest_idx
);
4200 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4201 redirect_edge_var_map_add (e
, nresult
, nop
, nloc
);
4205 /* Second, verify that all PHIs from OLD_BB have been handled. If not,
4206 we don't know what values from the other edges into NEW_BB to use. */
4207 for (ogsi
= gsi_start_phis (old_bb
); !gsi_end_p (ogsi
); gsi_next (&ogsi
))
4209 gphi
*ophi
= ogsi
.phi ();
4210 tree oresult
= gimple_phi_result (ophi
);
4211 if (!bitmap_bit_p (ophi_handled
, SSA_NAME_VERSION (oresult
)))
4215 /* Finally, move the edges and update the PHIs. */
4216 for (ei
= ei_start (old_bb
->preds
); (e
= ei_safe_edge (ei
)); )
4217 if (e
->flags
& EDGE_EH
)
4219 /* ??? CFG manipluation routines do not try to update loop
4220 form on edge redirection. Do so manually here for now. */
4221 /* If we redirect a loop entry or latch edge that will either create
4222 a multiple entry loop or rotate the loop. If the loops merge
4223 we may have created a loop with multiple latches.
4224 All of this isn't easily fixed thus cancel the affected loop
4225 and mark the other loop as possibly having multiple latches. */
4226 if (e
->dest
== e
->dest
->loop_father
->header
)
4228 mark_loop_for_removal (e
->dest
->loop_father
);
4229 new_bb
->loop_father
->latch
= NULL
;
4230 loops_state_set (LOOPS_MAY_HAVE_MULTIPLE_LATCHES
);
4232 redirect_eh_edge_1 (e
, new_bb
, change_region
);
4233 redirect_edge_succ (e
, new_bb
);
4234 flush_pending_stmts (e
);
4239 BITMAP_FREE (ophi_handled
);
4243 FOR_EACH_EDGE (e
, ei
, old_bb
->preds
)
4244 redirect_edge_var_map_clear (e
);
4245 BITMAP_FREE (ophi_handled
);
4249 /* A subroutine of cleanup_empty_eh. Move a landing pad LP from its
4250 old region to NEW_REGION at BB. */
4253 cleanup_empty_eh_move_lp (basic_block bb
, edge e_out
,
4254 eh_landing_pad lp
, eh_region new_region
)
4256 gimple_stmt_iterator gsi
;
4259 for (pp
= &lp
->region
->landing_pads
; *pp
!= lp
; pp
= &(*pp
)->next_lp
)
4263 lp
->region
= new_region
;
4264 lp
->next_lp
= new_region
->landing_pads
;
4265 new_region
->landing_pads
= lp
;
4267 /* Delete the RESX that was matched within the empty handler block. */
4268 gsi
= gsi_last_bb (bb
);
4269 unlink_stmt_vdef (gsi_stmt (gsi
));
4270 gsi_remove (&gsi
, true);
4272 /* Clean up E_OUT for the fallthru. */
4273 e_out
->flags
= (e_out
->flags
& ~EDGE_EH
) | EDGE_FALLTHRU
;
4274 e_out
->probability
= REG_BR_PROB_BASE
;
4275 e_out
->count
= e_out
->src
->count
;
4278 /* A subroutine of cleanup_empty_eh. Handle more complex cases of
4279 unsplitting than unsplit_eh was prepared to handle, e.g. when
4280 multiple incoming edges and phis are involved. */
4283 cleanup_empty_eh_unsplit (basic_block bb
, edge e_out
, eh_landing_pad lp
)
4285 gimple_stmt_iterator gsi
;
4288 /* We really ought not have totally lost everything following
4289 a landing pad label. Given that BB is empty, there had better
4291 gcc_assert (e_out
!= NULL
);
4293 /* The destination block must not already have a landing pad
4294 for a different region. */
4296 for (gsi
= gsi_start_bb (e_out
->dest
); !gsi_end_p (gsi
); gsi_next (&gsi
))
4298 glabel
*stmt
= dyn_cast
<glabel
*> (gsi_stmt (gsi
));
4303 lab
= gimple_label_label (stmt
);
4304 lp_nr
= EH_LANDING_PAD_NR (lab
);
4305 if (lp_nr
&& get_eh_region_from_lp_number (lp_nr
) != lp
->region
)
4309 /* Attempt to move the PHIs into the successor block. */
4310 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, false))
4312 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4314 "Unsplit EH landing pad %d to block %i "
4315 "(via cleanup_empty_eh).\n",
4316 lp
->index
, e_out
->dest
->index
);
4323 /* Return true if edge E_FIRST is part of an empty infinite loop
4324 or leads to such a loop through a series of single successor
4328 infinite_empty_loop_p (edge e_first
)
4330 bool inf_loop
= false;
4333 if (e_first
->dest
== e_first
->src
)
4336 e_first
->src
->aux
= (void *) 1;
4337 for (e
= e_first
; single_succ_p (e
->dest
); e
= single_succ_edge (e
->dest
))
4339 gimple_stmt_iterator gsi
;
4345 e
->dest
->aux
= (void *) 1;
4346 gsi
= gsi_after_labels (e
->dest
);
4347 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4348 gsi_next_nondebug (&gsi
);
4349 if (!gsi_end_p (gsi
))
4352 e_first
->src
->aux
= NULL
;
4353 for (e
= e_first
; e
->dest
->aux
; e
= single_succ_edge (e
->dest
))
4354 e
->dest
->aux
= NULL
;
4359 /* Examine the block associated with LP to determine if it's an empty
4360 handler for its EH region. If so, attempt to redirect EH edges to
4361 an outer region. Return true the CFG was updated in any way. This
4362 is similar to jump forwarding, just across EH edges. */
4365 cleanup_empty_eh (eh_landing_pad lp
)
4367 basic_block bb
= label_to_block (lp
->post_landing_pad
);
4368 gimple_stmt_iterator gsi
;
4370 eh_region new_region
;
4373 bool has_non_eh_pred
;
4377 /* There can be zero or one edges out of BB. This is the quickest test. */
4378 switch (EDGE_COUNT (bb
->succs
))
4384 e_out
= single_succ_edge (bb
);
4390 gsi
= gsi_last_nondebug_bb (bb
);
4391 resx
= gsi_stmt (gsi
);
4392 if (resx
&& is_gimple_resx (resx
))
4394 if (stmt_can_throw_external (resx
))
4395 optimize_clobbers (bb
);
4396 else if (sink_clobbers (bb
))
4400 gsi
= gsi_after_labels (bb
);
4402 /* Make sure to skip debug statements. */
4403 if (!gsi_end_p (gsi
) && is_gimple_debug (gsi_stmt (gsi
)))
4404 gsi_next_nondebug (&gsi
);
4406 /* If the block is totally empty, look for more unsplitting cases. */
4407 if (gsi_end_p (gsi
))
4409 /* For the degenerate case of an infinite loop bail out.
4410 If bb has no successors and is totally empty, which can happen e.g.
4411 because of incorrect noreturn attribute, bail out too. */
4413 || infinite_empty_loop_p (e_out
))
4416 return ret
| cleanup_empty_eh_unsplit (bb
, e_out
, lp
);
4419 /* The block should consist only of a single RESX statement, modulo a
4420 preceding call to __builtin_stack_restore if there is no outgoing
4421 edge, since the call can be eliminated in this case. */
4422 resx
= gsi_stmt (gsi
);
4423 if (!e_out
&& gimple_call_builtin_p (resx
, BUILT_IN_STACK_RESTORE
))
4425 gsi_next_nondebug (&gsi
);
4426 resx
= gsi_stmt (gsi
);
4428 if (!is_gimple_resx (resx
))
4430 gcc_assert (gsi_one_nondebug_before_end_p (gsi
));
4432 /* Determine if there are non-EH edges, or resx edges into the handler. */
4433 has_non_eh_pred
= false;
4434 FOR_EACH_EDGE (e
, ei
, bb
->preds
)
4435 if (!(e
->flags
& EDGE_EH
))
4436 has_non_eh_pred
= true;
4438 /* Find the handler that's outer of the empty handler by looking at
4439 where the RESX instruction was vectored. */
4440 new_lp_nr
= lookup_stmt_eh_lp (resx
);
4441 new_region
= get_eh_region_from_lp_number (new_lp_nr
);
4443 /* If there's no destination region within the current function,
4444 redirection is trivial via removing the throwing statements from
4445 the EH region, removing the EH edges, and allowing the block
4446 to go unreachable. */
4447 if (new_region
== NULL
)
4449 gcc_assert (e_out
== NULL
);
4450 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4451 if (e
->flags
& EDGE_EH
)
4453 gimple
*stmt
= last_stmt (e
->src
);
4454 remove_stmt_from_eh_lp (stmt
);
4462 /* If the destination region is a MUST_NOT_THROW, allow the runtime
4463 to handle the abort and allow the blocks to go unreachable. */
4464 if (new_region
->type
== ERT_MUST_NOT_THROW
)
4466 for (ei
= ei_start (bb
->preds
); (e
= ei_safe_edge (ei
)); )
4467 if (e
->flags
& EDGE_EH
)
4469 gimple
*stmt
= last_stmt (e
->src
);
4470 remove_stmt_from_eh_lp (stmt
);
4471 add_stmt_to_eh_lp (stmt
, new_lp_nr
);
4479 /* Try to redirect the EH edges and merge the PHIs into the destination
4480 landing pad block. If the merge succeeds, we'll already have redirected
4481 all the EH edges. The handler itself will go unreachable if there were
4483 if (cleanup_empty_eh_merge_phis (e_out
->dest
, bb
, e_out
, true))
4486 /* Finally, if all input edges are EH edges, then we can (potentially)
4487 reduce the number of transfers from the runtime by moving the landing
4488 pad from the original region to the new region. This is a win when
4489 we remove the last CLEANUP region along a particular exception
4490 propagation path. Since nothing changes except for the region with
4491 which the landing pad is associated, the PHI nodes do not need to be
4493 if (!has_non_eh_pred
)
4495 cleanup_empty_eh_move_lp (bb
, e_out
, lp
, new_region
);
4496 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4497 fprintf (dump_file
, "Empty EH handler %i moved to EH region %i.\n",
4498 lp
->index
, new_region
->index
);
4500 /* ??? The CFG didn't change, but we may have rendered the
4501 old EH region unreachable. Trigger a cleanup there. */
4508 if (dump_file
&& (dump_flags
& TDF_DETAILS
))
4509 fprintf (dump_file
, "Empty EH handler %i removed.\n", lp
->index
);
4510 remove_eh_landing_pad (lp
);
4514 /* Do a post-order traversal of the EH region tree. Examine each
4515 post_landing_pad block and see if we can eliminate it as empty. */
4518 cleanup_all_empty_eh (void)
4520 bool changed
= false;
4524 for (i
= 1; vec_safe_iterate (cfun
->eh
->lp_array
, i
, &lp
); ++i
)
4526 changed
|= cleanup_empty_eh (lp
);
4531 /* Perform cleanups and lowering of exception handling
4532 1) cleanups regions with handlers doing nothing are optimized out
4533 2) MUST_NOT_THROW regions that became dead because of 1) are optimized out
4534 3) Info about regions that are containing instructions, and regions
4535 reachable via local EH edges is collected
4536 4) Eh tree is pruned for regions no longer necessary.
4538 TODO: Push MUST_NOT_THROW regions to the root of the EH tree.
4539 Unify those that have the same failure decl and locus.
4543 execute_cleanup_eh_1 (void)
4545 /* Do this first: unsplit_all_eh and cleanup_all_empty_eh can die
4546 looking up unreachable landing pads. */
4547 remove_unreachable_handlers ();
4549 /* Watch out for the region tree vanishing due to all unreachable. */
4550 if (cfun
->eh
->region_tree
)
4552 bool changed
= false;
4555 changed
|= unsplit_all_eh ();
4556 changed
|= cleanup_all_empty_eh ();
4560 free_dominance_info (CDI_DOMINATORS
);
4561 free_dominance_info (CDI_POST_DOMINATORS
);
4563 /* We delayed all basic block deletion, as we may have performed
4564 cleanups on EH edges while non-EH edges were still present. */
4565 delete_unreachable_blocks ();
4567 /* We manipulated the landing pads. Remove any region that no
4568 longer has a landing pad. */
4569 remove_unreachable_handlers_no_lp ();
4571 return TODO_cleanup_cfg
| TODO_update_ssa_only_virtuals
;
4580 const pass_data pass_data_cleanup_eh
=
4582 GIMPLE_PASS
, /* type */
4583 "ehcleanup", /* name */
4584 OPTGROUP_NONE
, /* optinfo_flags */
4585 TV_TREE_EH
, /* tv_id */
4586 PROP_gimple_lcf
, /* properties_required */
4587 0, /* properties_provided */
4588 0, /* properties_destroyed */
4589 0, /* todo_flags_start */
4590 0, /* todo_flags_finish */
4593 class pass_cleanup_eh
: public gimple_opt_pass
4596 pass_cleanup_eh (gcc::context
*ctxt
)
4597 : gimple_opt_pass (pass_data_cleanup_eh
, ctxt
)
4600 /* opt_pass methods: */
4601 opt_pass
* clone () { return new pass_cleanup_eh (m_ctxt
); }
4602 virtual bool gate (function
*fun
)
4604 return fun
->eh
!= NULL
&& fun
->eh
->region_tree
!= NULL
;
4607 virtual unsigned int execute (function
*);
4609 }; // class pass_cleanup_eh
4612 pass_cleanup_eh::execute (function
*fun
)
4614 int ret
= execute_cleanup_eh_1 ();
4616 /* If the function no longer needs an EH personality routine
4617 clear it. This exposes cross-language inlining opportunities
4618 and avoids references to a never defined personality routine. */
4619 if (DECL_FUNCTION_PERSONALITY (current_function_decl
)
4620 && function_needs_eh_personality (fun
) != eh_personality_lang
)
4621 DECL_FUNCTION_PERSONALITY (current_function_decl
) = NULL_TREE
;
4629 make_pass_cleanup_eh (gcc::context
*ctxt
)
4631 return new pass_cleanup_eh (ctxt
);
4634 /* Verify that BB containing STMT as the last statement, has precisely the
4635 edge that make_eh_edges would create. */
4638 verify_eh_edges (gimple
*stmt
)
4640 basic_block bb
= gimple_bb (stmt
);
4641 eh_landing_pad lp
= NULL
;
4646 lp_nr
= lookup_stmt_eh_lp (stmt
);
4648 lp
= get_eh_landing_pad_from_number (lp_nr
);
4651 FOR_EACH_EDGE (e
, ei
, bb
->succs
)
4653 if (e
->flags
& EDGE_EH
)
4657 error ("BB %i has multiple EH edges", bb
->index
);
4669 error ("BB %i can not throw but has an EH edge", bb
->index
);
4675 if (!stmt_could_throw_p (stmt
))
4677 error ("BB %i last statement has incorrectly set lp", bb
->index
);
4681 if (eh_edge
== NULL
)
4683 error ("BB %i is missing an EH edge", bb
->index
);
4687 if (eh_edge
->dest
!= label_to_block (lp
->post_landing_pad
))
4689 error ("Incorrect EH edge %i->%i", bb
->index
, eh_edge
->dest
->index
);
4696 /* Similarly, but handle GIMPLE_EH_DISPATCH specifically. */
4699 verify_eh_dispatch_edge (geh_dispatch
*stmt
)
4703 basic_block src
, dst
;
4704 bool want_fallthru
= true;
4708 r
= get_eh_region_from_number (gimple_eh_dispatch_region (stmt
));
4709 src
= gimple_bb (stmt
);
4711 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4712 gcc_assert (e
->aux
== NULL
);
4717 for (c
= r
->u
.eh_try
.first_catch
; c
; c
= c
->next_catch
)
4719 dst
= label_to_block (c
->label
);
4720 e
= find_edge (src
, dst
);
4723 error ("BB %i is missing an edge", src
->index
);
4728 /* A catch-all handler doesn't have a fallthru. */
4729 if (c
->type_list
== NULL
)
4731 want_fallthru
= false;
4737 case ERT_ALLOWED_EXCEPTIONS
:
4738 dst
= label_to_block (r
->u
.allowed
.label
);
4739 e
= find_edge (src
, dst
);
4742 error ("BB %i is missing an edge", src
->index
);
4753 FOR_EACH_EDGE (e
, ei
, src
->succs
)
4755 if (e
->flags
& EDGE_FALLTHRU
)
4757 if (fall_edge
!= NULL
)
4759 error ("BB %i too many fallthru edges", src
->index
);
4768 error ("BB %i has incorrect edge", src
->index
);
4772 if ((fall_edge
!= NULL
) ^ want_fallthru
)
4774 error ("BB %i has incorrect fallthru edge", src
->index
);