1 /* Basic IPA optimizations and utilities.
2 Copyright (C) 2003-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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"
26 #include "stringpool.h"
28 #include "tree-pass.h"
29 #include "pointer-set.h"
30 #include "gimple-expr.h"
34 #include "tree-iterator.h"
35 #include "ipa-utils.h"
36 #include "ipa-inline.h"
37 #include "tree-inline.h"
41 /* Return true when NODE can not be local. Worker for cgraph_local_node_p. */
44 cgraph_non_local_node_p_1 (struct cgraph_node
*node
, void *data ATTRIBUTE_UNUSED
)
46 /* FIXME: Aliases can be local, but i386 gets thunks wrong then. */
47 return !(cgraph_only_called_directly_or_aliased_p (node
)
48 && !ipa_ref_has_aliases_p (&node
->ref_list
)
50 && !DECL_EXTERNAL (node
->decl
)
51 && !node
->externally_visible
52 && !node
->used_from_other_partition
53 && !node
->in_other_partition
);
56 /* Return true when function can be marked local. */
59 cgraph_local_node_p (struct cgraph_node
*node
)
61 struct cgraph_node
*n
= cgraph_function_or_thunk_node (node
, NULL
);
63 /* FIXME: thunks can be considered local, but we need prevent i386
64 from attempting to change calling convention of them. */
67 return !cgraph_for_node_and_aliases (n
,
68 cgraph_non_local_node_p_1
, NULL
, true);
72 /* Return true when NODE has ADDR reference. */
75 has_addr_references_p (struct cgraph_node
*node
,
76 void *data ATTRIBUTE_UNUSED
)
81 for (i
= 0; ipa_ref_list_referring_iterate (&node
->ref_list
,
83 if (ref
->use
== IPA_REF_ADDR
)
88 /* Look for all functions inlined to NODE and update their inlined_to pointers
92 update_inlined_to_pointer (struct cgraph_node
*node
, struct cgraph_node
*inlined_to
)
94 struct cgraph_edge
*e
;
95 for (e
= node
->callees
; e
; e
= e
->next_callee
)
96 if (e
->callee
->global
.inlined_to
)
98 e
->callee
->global
.inlined_to
= inlined_to
;
99 update_inlined_to_pointer (e
->callee
, inlined_to
);
103 /* Add symtab NODE to queue starting at FIRST.
105 The queue is linked via AUX pointers and terminated by pointer to 1.
106 We enqueue nodes at two occasions: when we find them reachable or when we find
107 their bodies needed for further clonning. In the second case we mark them
108 by pointer to 2 after processing so they are re-queue when they become
112 enqueue_node (symtab_node
*node
, symtab_node
**first
,
113 struct pointer_set_t
*reachable
)
115 /* Node is still in queue; do nothing. */
116 if (node
->aux
&& node
->aux
!= (void *) 2)
118 /* Node was already processed as unreachable, re-enqueue
119 only if it became reachable now. */
120 if (node
->aux
== (void *)2 && !pointer_set_contains (reachable
, node
))
126 /* Process references. */
129 process_references (struct ipa_ref_list
*list
,
131 bool before_inlining_p
,
132 struct pointer_set_t
*reachable
)
136 for (i
= 0; ipa_ref_list_reference_iterate (list
, i
, ref
); i
++)
138 symtab_node
*node
= ref
->referred
;
140 if (node
->definition
&& !node
->in_other_partition
141 && ((!DECL_EXTERNAL (node
->decl
) || node
->alias
)
142 || (((before_inlining_p
143 && (cgraph_state
< CGRAPH_STATE_IPA_SSA
144 || !lookup_attribute ("always_inline",
145 DECL_ATTRIBUTES (node
->decl
)))))
146 /* We use variable constructors during late complation for
147 constant folding. Keep references alive so partitioning
148 knows about potential references. */
149 || (TREE_CODE (node
->decl
) == VAR_DECL
151 && ctor_for_folding (node
->decl
)
152 != error_mark_node
))))
153 pointer_set_insert (reachable
, node
);
154 enqueue_node (node
, first
, reachable
);
158 /* EDGE is an polymorphic call. If BEFORE_INLINING_P is set, mark
159 all its potential targets as reachable to permit later inlining if
160 devirtualization happens. After inlining still keep their declarations
161 around, so we can devirtualize to a direct call.
163 Also try to make trivial devirutalization when no or only one target is
167 walk_polymorphic_call_targets (pointer_set_t
*reachable_call_targets
,
168 struct cgraph_edge
*edge
,
170 pointer_set_t
*reachable
, bool before_inlining_p
)
175 vec
<cgraph_node
*>targets
176 = possible_polymorphic_call_targets
177 (edge
, &final
, &cache_token
);
179 if (!pointer_set_insert (reachable_call_targets
,
182 for (i
= 0; i
< targets
.length (); i
++)
184 struct cgraph_node
*n
= targets
[i
];
186 /* Do not bother to mark virtual methods in anonymous namespace;
187 either we will find use of virtual table defining it, or it is
189 if (TREE_CODE (TREE_TYPE (n
->decl
)) == METHOD_TYPE
190 && type_in_anonymous_namespace_p
191 (method_class_type (TREE_TYPE (n
->decl
))))
194 /* Prior inlining, keep alive bodies of possible targets for
197 && (before_inlining_p
198 && (cgraph_state
< CGRAPH_STATE_IPA_SSA
199 || !lookup_attribute ("always_inline",
200 DECL_ATTRIBUTES (n
->decl
)))))
201 pointer_set_insert (reachable
, n
);
203 /* Even after inlining we want to keep the possible targets in the
204 boundary, so late passes can still produce direct call even if
205 the chance for inlining is lost. */
206 enqueue_node (n
, first
, reachable
);
210 /* Very trivial devirtualization; when the type is
211 final or anonymous (so we know all its derivation)
212 and there is only one possible virtual call target,
213 make the edge direct. */
216 if (targets
.length () <= 1)
218 cgraph_node
*target
, *node
= edge
->caller
;
219 if (targets
.length () == 1)
222 target
= cgraph_get_create_node
223 (builtin_decl_implicit (BUILT_IN_UNREACHABLE
));
227 "Devirtualizing call in %s/%i to %s/%i\n",
228 edge
->caller
->name (),
230 target
->name (), target
->order
);
231 edge
= cgraph_make_edge_direct (edge
, target
);
232 if (inline_summary_vec
)
233 inline_update_overall_summary (node
);
234 else if (edge
->call_stmt
)
235 cgraph_redirect_edge_call_stmt_to_callee (edge
);
240 /* Perform reachability analysis and reclaim all unreachable nodes.
242 The algorithm is basically mark&sweep but with some extra refinements:
244 - reachable extern inline functions needs special handling; the bodies needs
245 to stay in memory until inlining in hope that they will be inlined.
246 After inlining we release their bodies and turn them into unanalyzed
247 nodes even when they are reachable.
249 BEFORE_INLINING_P specify whether we are before or after inlining.
251 - virtual functions are kept in callgraph even if they seem unreachable in
252 hope calls to them will be devirtualized.
254 Again we remove them after inlining. In late optimization some
255 devirtualization may happen, but it is not important since we won't inline
256 the call. In theory early opts and IPA should work out all important cases.
258 - virtual clones needs bodies of their origins for later materialization;
259 this means that we want to keep the body even if the origin is unreachable
260 otherwise. To avoid origin from sitting in the callgraph and being
261 walked by IPA passes, we turn them into unanalyzed nodes with body
264 We maintain set of function declaration where body needs to stay in
265 body_needed_for_clonning
267 Inline clones represent special case: their declaration match the
268 declaration of origin and cgraph_remove_node already knows how to
269 reshape callgraph and preserve body when offline copy of function or
270 inline clone is being removed.
272 - C++ virtual tables keyed to other unit are represented as DECL_EXTERNAL
273 variables with DECL_INITIAL set. We finalize these and keep reachable
274 ones around for constant folding purposes. After inlining we however
275 stop walking their references to let everything static referneced by them
276 to be removed when it is otherwise unreachable.
278 We maintain queue of both reachable symbols (i.e. defined symbols that needs
279 to stay) and symbols that are in boundary (i.e. external symbols referenced
280 by reachable symbols or origins of clones). The queue is represented
281 as linked list by AUX pointer terminated by 1.
283 At the end we keep all reachable symbols. For symbols in boundary we always
284 turn definition into a declaration, but we may keep function body around
285 based on body_needed_for_clonning
287 All symbols that enter the queue have AUX pointer non-zero and are in the
288 boundary. Pointer set REACHABLE is used to track reachable symbols.
290 Every symbol can be visited twice - once as part of boundary and once
291 as real reachable symbol. enqueue_node needs to decide whether the
292 node needs to be re-queued for second processing. For this purpose
293 we set AUX pointer of processed symbols in the boundary to constant 2. */
296 symtab_remove_unreachable_nodes (bool before_inlining_p
, FILE *file
)
298 symtab_node
*first
= (symtab_node
*) (void *) 1;
299 struct cgraph_node
*node
, *next
;
300 varpool_node
*vnode
, *vnext
;
301 bool changed
= false;
302 struct pointer_set_t
*reachable
= pointer_set_create ();
303 struct pointer_set_t
*body_needed_for_clonning
= pointer_set_create ();
304 struct pointer_set_t
*reachable_call_targets
= pointer_set_create ();
306 timevar_push (TV_IPA_UNREACHABLE
);
307 #ifdef ENABLE_CHECKING
310 if (optimize
&& flag_devirtualize
)
311 build_type_inheritance_graph ();
313 fprintf (file
, "\nReclaiming functions:");
314 #ifdef ENABLE_CHECKING
315 FOR_EACH_FUNCTION (node
)
316 gcc_assert (!node
->aux
);
317 FOR_EACH_VARIABLE (vnode
)
318 gcc_assert (!vnode
->aux
);
320 /* Mark functions whose bodies are obviously needed.
321 This is mostly when they can be referenced externally. Inline clones
322 are special since their declarations are shared with master clone and thus
323 cgraph_can_remove_if_no_direct_calls_and_refs_p should not be called on them. */
324 FOR_EACH_FUNCTION (node
)
326 node
->used_as_abstract_origin
= false;
328 && !node
->global
.inlined_to
329 && !node
->in_other_partition
330 && !cgraph_can_remove_if_no_direct_calls_and_refs_p (node
))
332 gcc_assert (!node
->global
.inlined_to
);
333 pointer_set_insert (reachable
, node
);
334 enqueue_node (node
, &first
, reachable
);
337 gcc_assert (!node
->aux
);
340 /* Mark variables that are obviously needed. */
341 FOR_EACH_DEFINED_VARIABLE (vnode
)
342 if (!varpool_can_remove_if_no_refs (vnode
)
343 && !vnode
->in_other_partition
)
345 pointer_set_insert (reachable
, vnode
);
346 enqueue_node (vnode
, &first
, reachable
);
349 /* Perform reachability analysis. */
350 while (first
!= (symtab_node
*) (void *) 1)
352 bool in_boundary_p
= !pointer_set_contains (reachable
, first
);
353 symtab_node
*node
= first
;
355 first
= (symtab_node
*)first
->aux
;
357 /* If we are processing symbol in boundary, mark its AUX pointer for
358 possible later re-processing in enqueue_node. */
360 node
->aux
= (void *)2;
363 if (TREE_CODE (node
->decl
) == FUNCTION_DECL
364 && DECL_ABSTRACT_ORIGIN (node
->decl
))
366 struct cgraph_node
*origin_node
367 = cgraph_get_create_node (DECL_ABSTRACT_ORIGIN (node
->decl
));
368 origin_node
->used_as_abstract_origin
= true;
369 enqueue_node (origin_node
, &first
, reachable
);
371 /* If any symbol in a comdat group is reachable, force
372 all externally visible symbols in the same comdat
373 group to be reachable as well. Comdat-local symbols
374 can be discarded if all uses were inlined. */
375 if (node
->same_comdat_group
)
378 for (next
= node
->same_comdat_group
;
380 next
= next
->same_comdat_group
)
381 if (!symtab_comdat_local_p (next
)
382 && !pointer_set_insert (reachable
, next
))
383 enqueue_node (next
, &first
, reachable
);
385 /* Mark references as reachable. */
386 process_references (&node
->ref_list
, &first
,
387 before_inlining_p
, reachable
);
390 if (cgraph_node
*cnode
= dyn_cast
<cgraph_node
*> (node
))
392 /* Mark the callees reachable unless they are direct calls to extern
393 inline functions we decided to not inline. */
396 struct cgraph_edge
*e
;
397 /* Keep alive possible targets for devirtualization. */
398 if (optimize
&& flag_devirtualize
)
400 struct cgraph_edge
*next
;
401 for (e
= cnode
->indirect_calls
; e
; e
= next
)
403 next
= e
->next_callee
;
404 if (e
->indirect_info
->polymorphic
)
405 walk_polymorphic_call_targets (reachable_call_targets
,
406 e
, &first
, reachable
,
410 for (e
= cnode
->callees
; e
; e
= e
->next_callee
)
412 if (e
->callee
->definition
413 && !e
->callee
->in_other_partition
414 && (!e
->inline_failed
415 || !DECL_EXTERNAL (e
->callee
->decl
)
417 || before_inlining_p
))
419 /* Be sure that we will not optimize out alias target
421 if (DECL_EXTERNAL (e
->callee
->decl
)
423 && before_inlining_p
)
425 pointer_set_insert (reachable
,
426 cgraph_function_node (e
->callee
));
428 pointer_set_insert (reachable
, e
->callee
);
430 enqueue_node (e
->callee
, &first
, reachable
);
433 /* When inline clone exists, mark body to be preserved so when removing
434 offline copy of the function we don't kill it. */
435 if (cnode
->global
.inlined_to
)
436 pointer_set_insert (body_needed_for_clonning
, cnode
->decl
);
438 /* For non-inline clones, force their origins to the boundary and ensure
439 that body is not removed. */
440 while (cnode
->clone_of
)
442 bool noninline
= cnode
->clone_of
->decl
!= cnode
->decl
;
443 cnode
= cnode
->clone_of
;
446 pointer_set_insert (body_needed_for_clonning
, cnode
->decl
);
447 enqueue_node (cnode
, &first
, reachable
);
452 /* If any reachable function has simd clones, mark them as
453 reachable as well. */
454 if (cnode
->simd_clones
)
457 for (next
= cnode
->simd_clones
;
459 next
= next
->simdclone
->next_clone
)
461 || !pointer_set_insert (reachable
, next
))
462 enqueue_node (next
, &first
, reachable
);
465 /* When we see constructor of external variable, keep referred nodes in the
466 boundary. This will also hold initializers of the external vars NODE
468 varpool_node
*vnode
= dyn_cast
<varpool_node
*> (node
);
470 && DECL_EXTERNAL (node
->decl
)
475 for (int i
= 0; ipa_ref_list_reference_iterate (&node
->ref_list
, i
, ref
); i
++)
476 enqueue_node (ref
->referred
, &first
, reachable
);
480 /* Remove unreachable functions. */
481 for (node
= cgraph_first_function (); node
; node
= next
)
483 next
= cgraph_next_function (node
);
485 /* If node is not needed at all, remove it. */
489 fprintf (file
, " %s/%i", node
->name (), node
->order
);
490 cgraph_remove_node (node
);
493 /* If node is unreachable, remove its body. */
494 else if (!pointer_set_contains (reachable
, node
))
496 if (!pointer_set_contains (body_needed_for_clonning
, node
->decl
))
497 cgraph_release_function_body (node
);
498 else if (!node
->clone_of
)
499 gcc_assert (in_lto_p
|| DECL_RESULT (node
->decl
));
500 if (node
->definition
)
503 fprintf (file
, " %s/%i", node
->name (), node
->order
);
504 node
->body_removed
= true;
505 node
->analyzed
= false;
506 node
->definition
= false;
507 node
->cpp_implicit_alias
= false;
509 node
->thunk
.thunk_p
= false;
510 node
->weakref
= false;
511 /* After early inlining we drop always_inline attributes on
512 bodies of functions that are still referenced (have their
514 DECL_ATTRIBUTES (node
->decl
)
515 = remove_attribute ("always_inline",
516 DECL_ATTRIBUTES (node
->decl
));
517 if (!node
->in_other_partition
)
518 node
->local
.local
= false;
519 cgraph_node_remove_callees (node
);
520 ipa_remove_all_references (&node
->ref_list
);
525 gcc_assert (node
->clone_of
|| !cgraph_function_with_gimple_body_p (node
)
526 || in_lto_p
|| DECL_RESULT (node
->decl
));
529 /* Inline clones might be kept around so their materializing allows further
530 cloning. If the function the clone is inlined into is removed, we need
531 to turn it into normal cone. */
532 FOR_EACH_FUNCTION (node
)
534 if (node
->global
.inlined_to
537 gcc_assert (node
->clones
);
538 node
->global
.inlined_to
= NULL
;
539 update_inlined_to_pointer (node
, node
);
544 /* Remove unreachable variables. */
546 fprintf (file
, "\nReclaiming variables:");
547 for (vnode
= varpool_first_variable (); vnode
; vnode
= vnext
)
549 vnext
= varpool_next_variable (vnode
);
551 /* For can_refer_decl_in_current_unit_p we want to track for
552 all external variables if they are defined in other partition
554 && (!flag_ltrans
|| !DECL_EXTERNAL (vnode
->decl
)))
557 fprintf (file
, " %s/%i", vnode
->name (), vnode
->order
);
558 varpool_remove_node (vnode
);
561 else if (!pointer_set_contains (reachable
, vnode
))
564 if (vnode
->definition
)
567 fprintf (file
, " %s", vnode
->name ());
570 vnode
->body_removed
= true;
571 vnode
->definition
= false;
572 vnode
->analyzed
= false;
575 /* Keep body if it may be useful for constant folding. */
576 if ((init
= ctor_for_folding (vnode
->decl
)) == error_mark_node
)
577 varpool_remove_initializer (vnode
);
579 DECL_INITIAL (vnode
->decl
) = init
;
580 ipa_remove_all_references (&vnode
->ref_list
);
586 pointer_set_destroy (reachable
);
587 pointer_set_destroy (body_needed_for_clonning
);
588 pointer_set_destroy (reachable_call_targets
);
590 /* Now update address_taken flags and try to promote functions to be local. */
592 fprintf (file
, "\nClearing address taken flags:");
593 FOR_EACH_DEFINED_FUNCTION (node
)
594 if (node
->address_taken
595 && !node
->used_from_other_partition
)
597 if (!cgraph_for_node_and_aliases (node
, has_addr_references_p
, NULL
, true))
600 fprintf (file
, " %s", node
->name ());
601 node
->address_taken
= false;
603 if (cgraph_local_node_p (node
))
605 node
->local
.local
= true;
607 fprintf (file
, " (local)");
612 fprintf (file
, "\n");
614 #ifdef ENABLE_CHECKING
618 /* If we removed something, perhaps profile could be improved. */
619 if (changed
&& optimize
&& inline_edge_summary_vec
.exists ())
620 FOR_EACH_DEFINED_FUNCTION (node
)
621 ipa_propagate_frequency (node
);
623 timevar_pop (TV_IPA_UNREACHABLE
);
627 /* Discover variables that have no longer address taken or that are read only
628 and update their flags.
630 FIXME: This can not be done in between gimplify and omp_expand since
631 readonly flag plays role on what is shared and what is not. Currently we do
632 this transformation as part of whole program visibility and re-do at
633 ipa-reference pass (to take into account clonning), but it would
634 make sense to do it before early optimizations. */
637 ipa_discover_readonly_nonaddressable_vars (void)
641 fprintf (dump_file
, "Clearing variable flags:");
642 FOR_EACH_VARIABLE (vnode
)
643 if (vnode
->definition
&& varpool_all_refs_explicit_p (vnode
)
644 && (TREE_ADDRESSABLE (vnode
->decl
)
645 || !TREE_READONLY (vnode
->decl
)))
647 bool written
= false;
648 bool address_taken
= false;
651 for (i
= 0; ipa_ref_list_referring_iterate (&vnode
->ref_list
,
653 && (!written
|| !address_taken
); i
++)
657 address_taken
= true;
665 if (TREE_ADDRESSABLE (vnode
->decl
) && !address_taken
)
668 fprintf (dump_file
, " %s (addressable)", vnode
->name ());
669 TREE_ADDRESSABLE (vnode
->decl
) = 0;
671 if (!TREE_READONLY (vnode
->decl
) && !address_taken
&& !written
672 /* Making variable in explicit section readonly can cause section
674 See e.g. gcc.c-torture/compile/pr23237.c */
675 && DECL_SECTION_NAME (vnode
->decl
) == NULL
)
678 fprintf (dump_file
, " %s (read-only)", vnode
->name ());
679 TREE_READONLY (vnode
->decl
) = 1;
683 fprintf (dump_file
, "\n");
686 /* Return true when there is a reference to node and it is not vtable. */
688 address_taken_from_non_vtable_p (symtab_node
*node
)
692 for (i
= 0; ipa_ref_list_referring_iterate (&node
->ref_list
,
694 if (ref
->use
== IPA_REF_ADDR
)
697 if (is_a
<cgraph_node
*> (ref
->referring
))
699 node
= ipa_ref_referring_varpool_node (ref
);
700 if (!DECL_VIRTUAL_P (node
->decl
))
706 /* A helper for comdat_can_be_unshared_p. */
709 comdat_can_be_unshared_p_1 (symtab_node
*node
)
711 /* When address is taken, we don't know if equality comparison won't
712 break eventually. Exception are virutal functions, C++
713 constructors/destructors and vtables, where this is not possible by
714 language standard. */
715 if (!DECL_VIRTUAL_P (node
->decl
)
716 && (TREE_CODE (node
->decl
) != FUNCTION_DECL
717 || (!DECL_CXX_CONSTRUCTOR_P (node
->decl
)
718 && !DECL_CXX_DESTRUCTOR_P (node
->decl
)))
719 && address_taken_from_non_vtable_p (node
))
722 /* If the symbol is used in some weird way, better to not touch it. */
723 if (node
->force_output
)
726 /* Explicit instantiations needs to be output when possibly
728 if (node
->forced_by_abi
729 && TREE_PUBLIC (node
->decl
)
730 && (node
->resolution
!= LDPR_PREVAILING_DEF_IRONLY
731 && !flag_whole_program
))
734 /* Non-readonly and volatile variables can not be duplicated. */
735 if (is_a
<varpool_node
*> (node
)
736 && (!TREE_READONLY (node
->decl
)
737 || TREE_THIS_VOLATILE (node
->decl
)))
742 /* COMDAT functions must be shared only if they have address taken,
743 otherwise we can produce our own private implementation with
745 Return true when turning COMDAT functoin static can not lead to wrong
746 code when the resulting object links with a library defining same COMDAT.
748 Virtual functions do have their addresses taken from the vtables,
749 but in C++ there is no way to compare their addresses for equality. */
752 comdat_can_be_unshared_p (symtab_node
*node
)
754 if (!comdat_can_be_unshared_p_1 (node
))
756 if (node
->same_comdat_group
)
760 /* If more than one function is in the same COMDAT group, it must
761 be shared even if just one function in the comdat group has
763 for (next
= node
->same_comdat_group
;
764 next
!= node
; next
= next
->same_comdat_group
)
765 if (!comdat_can_be_unshared_p_1 (next
))
771 /* Return true when function NODE should be considered externally visible. */
774 cgraph_externally_visible_p (struct cgraph_node
*node
,
777 if (!node
->definition
)
779 if (!TREE_PUBLIC (node
->decl
)
780 || DECL_EXTERNAL (node
->decl
))
783 /* Do not try to localize built-in functions yet. One of problems is that we
784 end up mangling their asm for WHOPR that makes it impossible to call them
785 using the implicit built-in declarations anymore. Similarly this enables
786 us to remove them as unreachable before actual calls may appear during
787 expansion or folding. */
788 if (DECL_BUILT_IN (node
->decl
))
791 /* If linker counts on us, we must preserve the function. */
792 if (symtab_used_from_object_file_p (node
))
794 if (DECL_PRESERVE_P (node
->decl
))
796 if (lookup_attribute ("externally_visible",
797 DECL_ATTRIBUTES (node
->decl
)))
799 if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
800 && lookup_attribute ("dllexport",
801 DECL_ATTRIBUTES (node
->decl
)))
803 if (node
->resolution
== LDPR_PREVAILING_DEF_IRONLY
)
805 /* When doing LTO or whole program, we can bring COMDAT functoins static.
806 This improves code quality and we know we will duplicate them at most twice
807 (in the case that we are not using plugin and link with object file
808 implementing same COMDAT) */
809 if ((in_lto_p
|| whole_program
)
810 && DECL_COMDAT (node
->decl
)
811 && comdat_can_be_unshared_p (node
))
814 /* When doing link time optimizations, hidden symbols become local. */
816 && (DECL_VISIBILITY (node
->decl
) == VISIBILITY_HIDDEN
817 || DECL_VISIBILITY (node
->decl
) == VISIBILITY_INTERNAL
)
818 /* Be sure that node is defined in IR file, not in other object
819 file. In that case we don't set used_from_other_object_file. */
822 else if (!whole_program
)
825 if (MAIN_NAME_P (DECL_NAME (node
->decl
)))
831 /* Return true when variable VNODE should be considered externally visible. */
834 varpool_externally_visible_p (varpool_node
*vnode
)
836 if (DECL_EXTERNAL (vnode
->decl
))
839 if (!TREE_PUBLIC (vnode
->decl
))
842 /* If linker counts on us, we must preserve the function. */
843 if (symtab_used_from_object_file_p (vnode
))
846 if (DECL_HARD_REGISTER (vnode
->decl
))
848 if (DECL_PRESERVE_P (vnode
->decl
))
850 if (lookup_attribute ("externally_visible",
851 DECL_ATTRIBUTES (vnode
->decl
)))
853 if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
854 && lookup_attribute ("dllexport",
855 DECL_ATTRIBUTES (vnode
->decl
)))
858 /* See if we have linker information about symbol not being used or
859 if we need to make guess based on the declaration.
861 Even if the linker clams the symbol is unused, never bring internal
862 symbols that are declared by user as used or externally visible.
863 This is needed for i.e. references from asm statements. */
864 if (symtab_used_from_object_file_p (vnode
))
866 if (vnode
->resolution
== LDPR_PREVAILING_DEF_IRONLY
)
869 /* As a special case, the COMDAT virtual tables can be unshared.
870 In LTO mode turn vtables into static variables. The variable is readonly,
871 so this does not enable more optimization, but referring static var
872 is faster for dynamic linking. Also this match logic hidding vtables
873 from LTO symbol tables. */
874 if ((in_lto_p
|| flag_whole_program
)
875 && DECL_COMDAT (vnode
->decl
)
876 && comdat_can_be_unshared_p (vnode
))
879 /* When doing link time optimizations, hidden symbols become local. */
881 && (DECL_VISIBILITY (vnode
->decl
) == VISIBILITY_HIDDEN
882 || DECL_VISIBILITY (vnode
->decl
) == VISIBILITY_INTERNAL
)
883 /* Be sure that node is defined in IR file, not in other object
884 file. In that case we don't set used_from_other_object_file. */
885 && vnode
->definition
)
887 else if (!flag_whole_program
)
890 /* Do not attempt to privatize COMDATS by default.
891 This would break linking with C++ libraries sharing
894 FIXME: We can do so for readonly vars with no address taken and
895 possibly also for vtables since no direct pointer comparsion is done.
896 It might be interesting to do so to reduce linking overhead. */
897 if (DECL_COMDAT (vnode
->decl
) || DECL_WEAK (vnode
->decl
))
902 /* Return true if reference to NODE can be replaced by a local alias.
903 Local aliases save dynamic linking overhead and enable more optimizations.
907 can_replace_by_local_alias (symtab_node
*node
)
909 return (symtab_node_availability (node
) > AVAIL_OVERWRITABLE
910 && !symtab_can_be_discarded (node
));
913 /* Mark visibility of all functions.
915 A local function is one whose calls can occur only in the current
916 compilation unit and all its calls are explicit, so we can change
917 its calling convention. We simply mark all static functions whose
918 address is not taken as local.
920 We also change the TREE_PUBLIC flag of all declarations that are public
921 in language point of view but we want to overwrite this default
922 via visibilities for the backend point of view. */
925 function_and_variable_visibility (bool whole_program
)
927 struct cgraph_node
*node
;
930 /* All aliases should be procssed at this point. */
931 gcc_checking_assert (!alias_pairs
|| !alias_pairs
->length ());
933 FOR_EACH_FUNCTION (node
)
935 int flags
= flags_from_decl_or_type (node
->decl
);
937 /* Optimize away PURE and CONST constructors and destructors. */
939 && (flags
& (ECF_CONST
| ECF_PURE
))
940 && !(flags
& ECF_LOOPING_CONST_OR_PURE
))
942 DECL_STATIC_CONSTRUCTOR (node
->decl
) = 0;
943 DECL_STATIC_DESTRUCTOR (node
->decl
) = 0;
946 /* Frontends and alias code marks nodes as needed before parsing is finished.
947 We may end up marking as node external nodes where this flag is meaningless
949 if (DECL_EXTERNAL (node
->decl
) || !node
->definition
)
951 node
->force_output
= 0;
952 node
->forced_by_abi
= 0;
955 /* C++ FE on lack of COMDAT support create local COMDAT functions
956 (that ought to be shared but can not due to object format
957 limitations). It is necessary to keep the flag to make rest of C++ FE
958 happy. Clear the flag here to avoid confusion in middle-end. */
959 if (DECL_COMDAT (node
->decl
) && !TREE_PUBLIC (node
->decl
))
960 DECL_COMDAT (node
->decl
) = 0;
962 /* For external decls stop tracking same_comdat_group. It doesn't matter
963 what comdat group they are in when they won't be emitted in this TU. */
964 if (node
->same_comdat_group
&& DECL_EXTERNAL (node
->decl
))
966 #ifdef ENABLE_CHECKING
969 for (n
= node
->same_comdat_group
;
971 n
= n
->same_comdat_group
)
972 /* If at least one of same comdat group functions is external,
973 all of them have to be, otherwise it is a front-end bug. */
974 gcc_assert (DECL_EXTERNAL (n
->decl
));
976 symtab_dissolve_same_comdat_group_list (node
);
978 gcc_assert ((!DECL_WEAK (node
->decl
)
979 && !DECL_COMDAT (node
->decl
))
980 || TREE_PUBLIC (node
->decl
)
982 || DECL_EXTERNAL (node
->decl
));
983 if (cgraph_externally_visible_p (node
, whole_program
))
985 gcc_assert (!node
->global
.inlined_to
);
986 node
->externally_visible
= true;
990 node
->externally_visible
= false;
991 node
->forced_by_abi
= false;
993 if (!node
->externally_visible
994 && node
->definition
&& !node
->weakref
995 && !DECL_EXTERNAL (node
->decl
))
997 gcc_assert (whole_program
|| in_lto_p
998 || !TREE_PUBLIC (node
->decl
));
999 node
->unique_name
= ((node
->resolution
== LDPR_PREVAILING_DEF_IRONLY
1000 || node
->unique_name
1001 || node
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
)
1002 && TREE_PUBLIC (node
->decl
));
1003 node
->resolution
= LDPR_PREVAILING_DEF_IRONLY
;
1004 if (node
->same_comdat_group
&& TREE_PUBLIC (node
->decl
))
1006 symtab_node
*next
= node
;
1008 /* Set all members of comdat group local. */
1009 if (node
->same_comdat_group
)
1010 for (next
= node
->same_comdat_group
;
1012 next
= next
->same_comdat_group
)
1014 symtab_make_decl_local (next
->decl
);
1015 next
->unique_name
= ((next
->resolution
== LDPR_PREVAILING_DEF_IRONLY
1016 || next
->unique_name
1017 || next
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
)
1018 && TREE_PUBLIC (next
->decl
));
1020 /* cgraph_externally_visible_p has already checked all other nodes
1021 in the group and they will all be made local. We need to
1022 dissolve the group at once so that the predicate does not
1024 symtab_dissolve_same_comdat_group_list (node
);
1026 symtab_make_decl_local (node
->decl
);
1029 if (node
->thunk
.thunk_p
1030 && TREE_PUBLIC (node
->decl
))
1032 struct cgraph_node
*decl_node
= node
;
1034 decl_node
= cgraph_function_node (decl_node
->callees
->callee
, NULL
);
1036 /* Thunks have the same visibility as function they are attached to.
1037 Make sure the C++ front end set this up properly. */
1038 if (DECL_ONE_ONLY (decl_node
->decl
))
1040 gcc_checking_assert (DECL_COMDAT (node
->decl
)
1041 == DECL_COMDAT (decl_node
->decl
));
1042 gcc_checking_assert (DECL_COMDAT_GROUP (node
->decl
)
1043 == DECL_COMDAT_GROUP (decl_node
->decl
));
1044 gcc_checking_assert (node
->same_comdat_group
);
1046 node
->forced_by_abi
= decl_node
->forced_by_abi
;
1047 if (DECL_EXTERNAL (decl_node
->decl
))
1048 DECL_EXTERNAL (node
->decl
) = 1;
1051 /* If whole comdat group is used only within LTO code, we can dissolve it,
1052 we handle the unification ourselves.
1053 We keep COMDAT and weak so visibility out of DSO does not change.
1054 Later we may bring the symbols static if they are not exported. */
1055 if (DECL_ONE_ONLY (node
->decl
)
1056 && (node
->resolution
== LDPR_PREVAILING_DEF_IRONLY
1057 || node
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
))
1059 symtab_node
*next
= node
;
1061 if (node
->same_comdat_group
)
1062 for (next
= node
->same_comdat_group
;
1064 next
= next
->same_comdat_group
)
1065 if (next
->externally_visible
1066 && (next
->resolution
!= LDPR_PREVAILING_DEF_IRONLY
1067 && next
->resolution
!= LDPR_PREVAILING_DEF_IRONLY_EXP
))
1071 if (node
->same_comdat_group
)
1072 for (next
= node
->same_comdat_group
;
1074 next
= next
->same_comdat_group
)
1076 DECL_COMDAT_GROUP (next
->decl
) = NULL
;
1077 DECL_WEAK (next
->decl
) = false;
1079 DECL_COMDAT_GROUP (node
->decl
) = NULL
;
1080 symtab_dissolve_same_comdat_group_list (node
);
1084 FOR_EACH_DEFINED_FUNCTION (node
)
1086 node
->local
.local
|= cgraph_local_node_p (node
);
1088 /* If we know that function can not be overwritten by a different semantics
1089 and moreover its section can not be discarded, replace all direct calls
1090 by calls to an nonoverwritable alias. This make dynamic linking
1091 cheaper and enable more optimization.
1093 TODO: We can also update virtual tables. */
1094 if (node
->callers
&& can_replace_by_local_alias (node
))
1096 struct cgraph_node
*alias
= cgraph (symtab_nonoverwritable_alias (node
));
1098 if (alias
&& alias
!= node
)
1100 while (node
->callers
)
1102 struct cgraph_edge
*e
= node
->callers
;
1104 cgraph_redirect_edge_callee (e
, alias
);
1105 if (gimple_has_body_p (e
->caller
->decl
))
1107 push_cfun (DECL_STRUCT_FUNCTION (e
->caller
->decl
));
1108 cgraph_redirect_edge_call_stmt_to_callee (e
);
1115 FOR_EACH_VARIABLE (vnode
)
1117 /* weak flag makes no sense on local variables. */
1118 gcc_assert (!DECL_WEAK (vnode
->decl
)
1120 || TREE_PUBLIC (vnode
->decl
)
1121 || DECL_EXTERNAL (vnode
->decl
));
1122 /* In several cases declarations can not be common:
1124 - when declaration has initializer
1125 - when it is in weak
1126 - when it has specific section
1127 - when it resides in non-generic address space.
1128 - if declaration is local, it will get into .local common section
1129 so common flag is not needed. Frontends still produce these in
1130 certain cases, such as for:
1132 static int a __attribute__ ((common))
1134 Canonicalize things here and clear the redundant flag. */
1135 if (DECL_COMMON (vnode
->decl
)
1136 && (!(TREE_PUBLIC (vnode
->decl
)
1137 || DECL_EXTERNAL (vnode
->decl
))
1138 || (DECL_INITIAL (vnode
->decl
)
1139 && DECL_INITIAL (vnode
->decl
) != error_mark_node
)
1140 || DECL_WEAK (vnode
->decl
)
1141 || DECL_SECTION_NAME (vnode
->decl
) != NULL
1142 || ! (ADDR_SPACE_GENERIC_P
1143 (TYPE_ADDR_SPACE (TREE_TYPE (vnode
->decl
))))))
1144 DECL_COMMON (vnode
->decl
) = 0;
1146 FOR_EACH_DEFINED_VARIABLE (vnode
)
1148 if (!vnode
->definition
)
1150 if (varpool_externally_visible_p (vnode
))
1151 vnode
->externally_visible
= true;
1154 vnode
->externally_visible
= false;
1155 vnode
->forced_by_abi
= false;
1157 if (!vnode
->externally_visible
1160 gcc_assert (in_lto_p
|| whole_program
|| !TREE_PUBLIC (vnode
->decl
));
1161 vnode
->unique_name
= ((vnode
->resolution
== LDPR_PREVAILING_DEF_IRONLY
1162 || vnode
->resolution
== LDPR_PREVAILING_DEF_IRONLY_EXP
)
1163 && TREE_PUBLIC (vnode
->decl
));
1164 symtab_make_decl_local (vnode
->decl
);
1165 if (vnode
->same_comdat_group
)
1166 symtab_dissolve_same_comdat_group_list (vnode
);
1167 vnode
->resolution
= LDPR_PREVAILING_DEF_IRONLY
;
1173 fprintf (dump_file
, "\nMarking local functions:");
1174 FOR_EACH_DEFINED_FUNCTION (node
)
1175 if (node
->local
.local
)
1176 fprintf (dump_file
, " %s", node
->name ());
1177 fprintf (dump_file
, "\n\n");
1178 fprintf (dump_file
, "\nMarking externally visible functions:");
1179 FOR_EACH_DEFINED_FUNCTION (node
)
1180 if (node
->externally_visible
)
1181 fprintf (dump_file
, " %s", node
->name ());
1182 fprintf (dump_file
, "\n\n");
1183 fprintf (dump_file
, "\nMarking externally visible variables:");
1184 FOR_EACH_DEFINED_VARIABLE (vnode
)
1185 if (vnode
->externally_visible
)
1186 fprintf (dump_file
, " %s", vnode
->name ());
1187 fprintf (dump_file
, "\n\n");
1189 cgraph_function_flags_ready
= true;
1193 /* Local function pass handling visibilities. This happens before LTO streaming
1194 so in particular -fwhole-program should be ignored at this level. */
1198 const pass_data pass_data_ipa_function_and_variable_visibility
=
1200 SIMPLE_IPA_PASS
, /* type */
1201 "visibility", /* name */
1202 OPTGROUP_NONE
, /* optinfo_flags */
1203 true, /* has_execute */
1204 TV_CGRAPHOPT
, /* tv_id */
1205 0, /* properties_required */
1206 0, /* properties_provided */
1207 0, /* properties_destroyed */
1208 0, /* todo_flags_start */
1209 ( TODO_remove_functions
| TODO_dump_symtab
), /* todo_flags_finish */
1212 class pass_ipa_function_and_variable_visibility
: public simple_ipa_opt_pass
1215 pass_ipa_function_and_variable_visibility (gcc::context
*ctxt
)
1216 : simple_ipa_opt_pass (pass_data_ipa_function_and_variable_visibility
,
1220 /* opt_pass methods: */
1221 virtual unsigned int execute (function
*)
1223 return function_and_variable_visibility (flag_whole_program
&& !flag_lto
);
1226 }; // class pass_ipa_function_and_variable_visibility
1230 simple_ipa_opt_pass
*
1231 make_pass_ipa_function_and_variable_visibility (gcc::context
*ctxt
)
1233 return new pass_ipa_function_and_variable_visibility (ctxt
);
1236 /* Free inline summary. */
1240 const pass_data pass_data_ipa_free_inline_summary
=
1242 SIMPLE_IPA_PASS
, /* type */
1243 "*free_inline_summary", /* name */
1244 OPTGROUP_NONE
, /* optinfo_flags */
1245 true, /* has_execute */
1246 TV_IPA_FREE_INLINE_SUMMARY
, /* tv_id */
1247 0, /* properties_required */
1248 0, /* properties_provided */
1249 0, /* properties_destroyed */
1250 0, /* todo_flags_start */
1251 0, /* todo_flags_finish */
1254 class pass_ipa_free_inline_summary
: public simple_ipa_opt_pass
1257 pass_ipa_free_inline_summary (gcc::context
*ctxt
)
1258 : simple_ipa_opt_pass (pass_data_ipa_free_inline_summary
, ctxt
)
1261 /* opt_pass methods: */
1262 virtual unsigned int execute (function
*)
1264 inline_free_summary ();
1268 }; // class pass_ipa_free_inline_summary
1272 simple_ipa_opt_pass
*
1273 make_pass_ipa_free_inline_summary (gcc::context
*ctxt
)
1275 return new pass_ipa_free_inline_summary (ctxt
);
1278 /* Bring functionss local at LTO time with -fwhole-program. */
1281 whole_program_function_and_variable_visibility (void)
1283 function_and_variable_visibility (flag_whole_program
);
1285 ipa_discover_readonly_nonaddressable_vars ();
1291 const pass_data pass_data_ipa_whole_program_visibility
=
1293 IPA_PASS
, /* type */
1294 "whole-program", /* name */
1295 OPTGROUP_NONE
, /* optinfo_flags */
1296 true, /* has_execute */
1297 TV_CGRAPHOPT
, /* tv_id */
1298 0, /* properties_required */
1299 0, /* properties_provided */
1300 0, /* properties_destroyed */
1301 0, /* todo_flags_start */
1302 ( TODO_remove_functions
| TODO_dump_symtab
), /* todo_flags_finish */
1305 class pass_ipa_whole_program_visibility
: public ipa_opt_pass_d
1308 pass_ipa_whole_program_visibility (gcc::context
*ctxt
)
1309 : ipa_opt_pass_d (pass_data_ipa_whole_program_visibility
, ctxt
,
1310 NULL
, /* generate_summary */
1311 NULL
, /* write_summary */
1312 NULL
, /* read_summary */
1313 NULL
, /* write_optimization_summary */
1314 NULL
, /* read_optimization_summary */
1315 NULL
, /* stmt_fixup */
1316 0, /* function_transform_todo_flags_start */
1317 NULL
, /* function_transform */
1318 NULL
) /* variable_transform */
1321 /* opt_pass methods: */
1323 virtual bool gate (function
*)
1325 /* Do not re-run on ltrans stage. */
1326 return !flag_ltrans
;
1328 virtual unsigned int execute (function
*)
1330 return whole_program_function_and_variable_visibility ();
1333 }; // class pass_ipa_whole_program_visibility
1338 make_pass_ipa_whole_program_visibility (gcc::context
*ctxt
)
1340 return new pass_ipa_whole_program_visibility (ctxt
);
1343 /* Generate and emit a static constructor or destructor. WHICH must
1344 be one of 'I' (for a constructor) or 'D' (for a destructor). BODY
1345 is a STATEMENT_LIST containing GENERIC statements. PRIORITY is the
1346 initialization priority for this constructor or destructor.
1348 FINAL specify whether the externally visible name for collect2 should
1352 cgraph_build_static_cdtor_1 (char which
, tree body
, int priority
, bool final
)
1354 static int counter
= 0;
1356 tree decl
, name
, resdecl
;
1358 /* The priority is encoded in the constructor or destructor name.
1359 collect2 will sort the names and arrange that they are called at
1362 sprintf (which_buf
, "%c_%.5d_%d", which
, priority
, counter
++);
1364 /* Proudce sane name but one not recognizable by collect2, just for the
1365 case we fail to inline the function. */
1366 sprintf (which_buf
, "sub_%c_%.5d_%d", which
, priority
, counter
++);
1367 name
= get_file_function_name (which_buf
);
1369 decl
= build_decl (input_location
, FUNCTION_DECL
, name
,
1370 build_function_type_list (void_type_node
, NULL_TREE
));
1371 current_function_decl
= decl
;
1373 resdecl
= build_decl (input_location
,
1374 RESULT_DECL
, NULL_TREE
, void_type_node
);
1375 DECL_ARTIFICIAL (resdecl
) = 1;
1376 DECL_RESULT (decl
) = resdecl
;
1377 DECL_CONTEXT (resdecl
) = decl
;
1379 allocate_struct_function (decl
, false);
1381 TREE_STATIC (decl
) = 1;
1382 TREE_USED (decl
) = 1;
1383 DECL_ARTIFICIAL (decl
) = 1;
1384 DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl
) = 1;
1385 DECL_SAVED_TREE (decl
) = body
;
1386 if (!targetm
.have_ctors_dtors
&& final
)
1388 TREE_PUBLIC (decl
) = 1;
1389 DECL_PRESERVE_P (decl
) = 1;
1391 DECL_UNINLINABLE (decl
) = 1;
1393 DECL_INITIAL (decl
) = make_node (BLOCK
);
1394 TREE_USED (DECL_INITIAL (decl
)) = 1;
1396 DECL_SOURCE_LOCATION (decl
) = input_location
;
1397 cfun
->function_end_locus
= input_location
;
1402 DECL_STATIC_CONSTRUCTOR (decl
) = 1;
1403 decl_init_priority_insert (decl
, priority
);
1406 DECL_STATIC_DESTRUCTOR (decl
) = 1;
1407 decl_fini_priority_insert (decl
, priority
);
1413 gimplify_function_tree (decl
);
1415 cgraph_add_new_function (decl
, false);
1418 current_function_decl
= NULL
;
1421 /* Generate and emit a static constructor or destructor. WHICH must
1422 be one of 'I' (for a constructor) or 'D' (for a destructor). BODY
1423 is a STATEMENT_LIST containing GENERIC statements. PRIORITY is the
1424 initialization priority for this constructor or destructor. */
1427 cgraph_build_static_cdtor (char which
, tree body
, int priority
)
1429 cgraph_build_static_cdtor_1 (which
, body
, priority
, false);
1432 /* A vector of FUNCTION_DECLs declared as static constructors. */
1433 static vec
<tree
> static_ctors
;
1434 /* A vector of FUNCTION_DECLs declared as static destructors. */
1435 static vec
<tree
> static_dtors
;
1437 /* When target does not have ctors and dtors, we call all constructor
1438 and destructor by special initialization/destruction function
1439 recognized by collect2.
1441 When we are going to build this function, collect all constructors and
1442 destructors and turn them into normal functions. */
1445 record_cdtor_fn (struct cgraph_node
*node
)
1447 if (DECL_STATIC_CONSTRUCTOR (node
->decl
))
1448 static_ctors
.safe_push (node
->decl
);
1449 if (DECL_STATIC_DESTRUCTOR (node
->decl
))
1450 static_dtors
.safe_push (node
->decl
);
1451 node
= cgraph_get_node (node
->decl
);
1452 DECL_DISREGARD_INLINE_LIMITS (node
->decl
) = 1;
1455 /* Define global constructors/destructor functions for the CDTORS, of
1456 which they are LEN. The CDTORS are sorted by initialization
1457 priority. If CTOR_P is true, these are constructors; otherwise,
1458 they are destructors. */
1461 build_cdtor (bool ctor_p
, vec
<tree
> cdtors
)
1464 size_t len
= cdtors
.length ();
1471 priority_type priority
;
1480 p
= ctor_p
? DECL_INIT_PRIORITY (fn
) : DECL_FINI_PRIORITY (fn
);
1483 else if (p
!= priority
)
1489 /* When there is only one cdtor and target supports them, do nothing. */
1491 && targetm
.have_ctors_dtors
)
1496 /* Find the next batch of constructors/destructors with the same
1497 initialization priority. */
1502 call
= build_call_expr (fn
, 0);
1504 DECL_STATIC_CONSTRUCTOR (fn
) = 0;
1506 DECL_STATIC_DESTRUCTOR (fn
) = 0;
1507 /* We do not want to optimize away pure/const calls here.
1508 When optimizing, these should be already removed, when not
1509 optimizing, we want user to be able to breakpoint in them. */
1510 TREE_SIDE_EFFECTS (call
) = 1;
1511 append_to_statement_list (call
, &body
);
1513 gcc_assert (body
!= NULL_TREE
);
1514 /* Generate a function to call all the function of like
1516 cgraph_build_static_cdtor_1 (ctor_p
? 'I' : 'D', body
, priority
, true);
1520 /* Comparison function for qsort. P1 and P2 are actually of type
1521 "tree *" and point to static constructors. DECL_INIT_PRIORITY is
1522 used to determine the sort order. */
1525 compare_ctor (const void *p1
, const void *p2
)
1532 f1
= *(const tree
*)p1
;
1533 f2
= *(const tree
*)p2
;
1534 priority1
= DECL_INIT_PRIORITY (f1
);
1535 priority2
= DECL_INIT_PRIORITY (f2
);
1537 if (priority1
< priority2
)
1539 else if (priority1
> priority2
)
1542 /* Ensure a stable sort. Constructors are executed in backwarding
1543 order to make LTO initialize braries first. */
1544 return DECL_UID (f2
) - DECL_UID (f1
);
1547 /* Comparison function for qsort. P1 and P2 are actually of type
1548 "tree *" and point to static destructors. DECL_FINI_PRIORITY is
1549 used to determine the sort order. */
1552 compare_dtor (const void *p1
, const void *p2
)
1559 f1
= *(const tree
*)p1
;
1560 f2
= *(const tree
*)p2
;
1561 priority1
= DECL_FINI_PRIORITY (f1
);
1562 priority2
= DECL_FINI_PRIORITY (f2
);
1564 if (priority1
< priority2
)
1566 else if (priority1
> priority2
)
1569 /* Ensure a stable sort. */
1570 return DECL_UID (f1
) - DECL_UID (f2
);
1573 /* Generate functions to call static constructors and destructors
1574 for targets that do not support .ctors/.dtors sections. These
1575 functions have magic names which are detected by collect2. */
1578 build_cdtor_fns (void)
1580 if (!static_ctors
.is_empty ())
1582 gcc_assert (!targetm
.have_ctors_dtors
|| in_lto_p
);
1583 static_ctors
.qsort (compare_ctor
);
1584 build_cdtor (/*ctor_p=*/true, static_ctors
);
1587 if (!static_dtors
.is_empty ())
1589 gcc_assert (!targetm
.have_ctors_dtors
|| in_lto_p
);
1590 static_dtors
.qsort (compare_dtor
);
1591 build_cdtor (/*ctor_p=*/false, static_dtors
);
1595 /* Look for constructors and destructors and produce function calling them.
1596 This is needed for targets not supporting ctors or dtors, but we perform the
1597 transformation also at linktime to merge possibly numerous
1598 constructors/destructors into single function to improve code locality and
1602 ipa_cdtor_merge (void)
1604 struct cgraph_node
*node
;
1605 FOR_EACH_DEFINED_FUNCTION (node
)
1606 if (DECL_STATIC_CONSTRUCTOR (node
->decl
)
1607 || DECL_STATIC_DESTRUCTOR (node
->decl
))
1608 record_cdtor_fn (node
);
1610 static_ctors
.release ();
1611 static_dtors
.release ();
1617 const pass_data pass_data_ipa_cdtor_merge
=
1619 IPA_PASS
, /* type */
1621 OPTGROUP_NONE
, /* optinfo_flags */
1622 true, /* has_execute */
1623 TV_CGRAPHOPT
, /* tv_id */
1624 0, /* properties_required */
1625 0, /* properties_provided */
1626 0, /* properties_destroyed */
1627 0, /* todo_flags_start */
1628 0, /* todo_flags_finish */
1631 class pass_ipa_cdtor_merge
: public ipa_opt_pass_d
1634 pass_ipa_cdtor_merge (gcc::context
*ctxt
)
1635 : ipa_opt_pass_d (pass_data_ipa_cdtor_merge
, ctxt
,
1636 NULL
, /* generate_summary */
1637 NULL
, /* write_summary */
1638 NULL
, /* read_summary */
1639 NULL
, /* write_optimization_summary */
1640 NULL
, /* read_optimization_summary */
1641 NULL
, /* stmt_fixup */
1642 0, /* function_transform_todo_flags_start */
1643 NULL
, /* function_transform */
1644 NULL
) /* variable_transform */
1647 /* opt_pass methods: */
1648 virtual bool gate (function
*);
1649 virtual unsigned int execute (function
*) { return ipa_cdtor_merge (); }
1651 }; // class pass_ipa_cdtor_merge
1654 pass_ipa_cdtor_merge::gate (function
*)
1656 /* Perform the pass when we have no ctors/dtors support
1657 or at LTO time to merge multiple constructors into single
1659 return !targetm
.have_ctors_dtors
|| (optimize
&& in_lto_p
);
1665 make_pass_ipa_cdtor_merge (gcc::context
*ctxt
)
1667 return new pass_ipa_cdtor_merge (ctxt
);