1 /* Basic IPA optimizations and utilities.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
23 #include "coretypes.h"
26 #include "tree-pass.h"
30 #include "pointer-set.h"
32 #include "tree-iterator.h"
33 #include "ipa-utils.h"
34 #include "pointer-set.h"
35 #include "ipa-inline.h"
37 /* Look for all functions inlined to NODE and update their inlined_to pointers
41 update_inlined_to_pointer (struct cgraph_node
*node
, struct cgraph_node
*inlined_to
)
43 struct cgraph_edge
*e
;
44 for (e
= node
->callees
; e
; e
= e
->next_callee
)
45 if (e
->callee
->global
.inlined_to
)
47 e
->callee
->global
.inlined_to
= inlined_to
;
48 update_inlined_to_pointer (e
->callee
, inlined_to
);
52 /* Add symtab NODE to queue starting at FIRST.
54 The queue is linked via AUX pointers and terminated by pointer to 1.
55 We enqueue nodes at two occasions: when we find them reachable or when we find
56 their bodies needed for further clonning. In the second case we mark them
57 by pointer to 2 after processing so they are re-queue when they become
61 enqueue_node (symtab_node node
, symtab_node
*first
,
62 struct pointer_set_t
*reachable
)
64 /* Node is still in queue; do nothing. */
65 if (node
->symbol
.aux
&& node
->symbol
.aux
!= (void *) 2)
67 /* Node was already processed as unreachable, re-enqueue
68 only if it became reachable now. */
69 if (node
->symbol
.aux
== (void *)2 && !pointer_set_contains (reachable
, node
))
71 node
->symbol
.aux
= *first
;
75 /* Process references. */
78 process_references (struct ipa_ref_list
*list
,
80 bool before_inlining_p
,
81 struct pointer_set_t
*reachable
)
85 for (i
= 0; ipa_ref_list_reference_iterate (list
, i
, ref
); i
++)
87 if (is_a
<cgraph_node
> (ref
->referred
))
89 struct cgraph_node
*node
= ipa_ref_node (ref
);
92 && (!DECL_EXTERNAL (node
->symbol
.decl
)
94 || before_inlining_p
))
95 pointer_set_insert (reachable
, node
);
96 enqueue_node ((symtab_node
) node
, first
, reachable
);
100 struct varpool_node
*node
= ipa_ref_varpool_node (ref
);
103 && (!DECL_EXTERNAL (node
->symbol
.decl
)
105 || before_inlining_p
))
106 pointer_set_insert (reachable
, node
);
107 enqueue_node ((symtab_node
) node
, first
, reachable
);
113 /* Return true when NODE can not be local. Worker for cgraph_local_node_p. */
116 cgraph_non_local_node_p_1 (struct cgraph_node
*node
, void *data ATTRIBUTE_UNUSED
)
118 /* FIXME: Aliases can be local, but i386 gets thunks wrong then. */
119 return !(cgraph_only_called_directly_or_aliased_p (node
)
120 && !ipa_ref_has_aliases_p (&node
->symbol
.ref_list
)
122 && !DECL_EXTERNAL (node
->symbol
.decl
)
123 && !node
->symbol
.externally_visible
124 && !node
->symbol
.used_from_other_partition
125 && !node
->symbol
.in_other_partition
);
128 /* Return true when function can be marked local. */
131 cgraph_local_node_p (struct cgraph_node
*node
)
133 struct cgraph_node
*n
= cgraph_function_or_thunk_node (node
, NULL
);
135 /* FIXME: thunks can be considered local, but we need prevent i386
136 from attempting to change calling convention of them. */
137 if (n
->thunk
.thunk_p
)
139 return !cgraph_for_node_and_aliases (n
,
140 cgraph_non_local_node_p_1
, NULL
, true);
144 /* Return true when NODE has ADDR reference. */
147 has_addr_references_p (struct cgraph_node
*node
,
148 void *data ATTRIBUTE_UNUSED
)
153 for (i
= 0; ipa_ref_list_referring_iterate (&node
->symbol
.ref_list
,
155 if (ref
->use
== IPA_REF_ADDR
)
160 /* Perform reachability analysis and reclaim all unreachable nodes.
162 The algorithm is basically mark&sweep but with some extra refinements:
164 - reachable extern inline functions needs special handling; the bodies needs
165 to stay in memory until inlining in hope that they will be inlined.
166 After inlining we release their bodies and turn them into unanalyzed
167 nodes even when they are reachable.
169 BEFORE_INLINING_P specify whether we are before or after inlining.
171 - virtual functions are kept in callgraph even if they seem unreachable in
172 hope calls to them will be devirtualized.
174 Again we remove them after inlining. In late optimization some
175 devirtualization may happen, but it is not importnat since we won't inline
176 the call. In theory early opts and IPA should work out all important cases.
178 - virtual clones needs bodies of their origins for later materialization;
179 this means that we want to keep the body even if the origin is unreachable
180 otherwise. To avoid origin from sitting in the callgraph and being
181 walked by IPA passes, we turn them into unanalyzed nodes with body
184 We maintain set of function declaration where body needs to stay in
185 body_needed_for_clonning
187 Inline clones represent special case: their declaration match the
188 declaration of origin and cgraph_remove_node already knows how to
189 reshape callgraph and preserve body when offline copy of function or
190 inline clone is being removed.
192 - C++ virtual tables keyed to other unit are represented as DECL_EXTERNAL
193 variables with DECL_INITIAL set. We finalize these and keep reachable
194 ones around for constant folding purposes. After inlining we however
195 stop walking their references to let everything static referneced by them
196 to be removed when it is otherwise unreachable.
198 We maintain queue of both reachable symbols (i.e. defined symbols that needs
199 to stay) and symbols that are in boundary (i.e. external symbols referenced
200 by reachable symbols or origins of clones). The queue is represented
201 as linked list by AUX pointer terminated by 1.
203 A the end we keep all reachable symbols. For symbols in boundary we always
204 turn definition into a declaration, but we may keep function body around
205 based on body_needed_for_clonning
207 All symbols that enter the queue have AUX pointer non-zero and are in the
208 boundary. Pointer set REACHABLE is used to track reachable symbols.
210 Every symbol can be visited twice - once as part of boundary and once
211 as real reachable symbol. enqueue_node needs to decide whether the
212 node needs to be re-queued for second processing. For this purpose
213 we set AUX pointer of processed symbols in the boundary to constant 2. */
216 symtab_remove_unreachable_nodes (bool before_inlining_p
, FILE *file
)
218 symtab_node first
= (symtab_node
) (void *) 1;
219 struct cgraph_node
*node
, *next
;
220 struct varpool_node
*vnode
, *vnext
;
221 bool changed
= false;
222 struct pointer_set_t
*reachable
= pointer_set_create ();
223 struct pointer_set_t
*body_needed_for_clonning
= pointer_set_create ();
225 #ifdef ENABLE_CHECKING
229 fprintf (file
, "\nReclaiming functions:");
230 #ifdef ENABLE_CHECKING
231 FOR_EACH_FUNCTION (node
)
232 gcc_assert (!node
->symbol
.aux
);
233 FOR_EACH_VARIABLE (vnode
)
234 gcc_assert (!vnode
->symbol
.aux
);
236 /* Mark functions whose bodies are obviously needed.
237 This is mostly when they can be referenced externally. Inline clones
238 are special since their declarations are shared with master clone and thus
239 cgraph_can_remove_if_no_direct_calls_and_refs_p should not be called on them. */
240 FOR_EACH_DEFINED_FUNCTION (node
)
241 if (!node
->global
.inlined_to
242 && (!cgraph_can_remove_if_no_direct_calls_and_refs_p (node
)
243 /* Keep around virtual functions for possible devirtualization. */
244 || (before_inlining_p
245 && DECL_VIRTUAL_P (node
->symbol
.decl
)
246 && (DECL_COMDAT (node
->symbol
.decl
) || DECL_EXTERNAL (node
->symbol
.decl
)))))
248 gcc_assert (!node
->global
.inlined_to
);
249 pointer_set_insert (reachable
, node
);
250 enqueue_node ((symtab_node
)node
, &first
, reachable
);
253 gcc_assert (!node
->symbol
.aux
);
255 /* Mark variables that are obviously needed. */
256 FOR_EACH_DEFINED_VARIABLE (vnode
)
257 if (!varpool_can_remove_if_no_refs (vnode
))
259 pointer_set_insert (reachable
, vnode
);
260 enqueue_node ((symtab_node
)vnode
, &first
, reachable
);
263 /* Perform reachability analysis. */
264 while (first
!= (symtab_node
) (void *) 1)
266 bool in_boundary_p
= !pointer_set_contains (reachable
, first
);
267 symtab_node node
= first
;
269 first
= (symtab_node
)first
->symbol
.aux
;
271 /* If we are processing symbol in boundary, mark its AUX pointer for
272 possible later re-processing in enqueue_node. */
274 node
->symbol
.aux
= (void *)2;
277 /* If any symbol in a comdat group is reachable, force
278 all other in the same comdat group to be also reachable. */
279 if (node
->symbol
.same_comdat_group
)
282 for (next
= node
->symbol
.same_comdat_group
;
284 next
= next
->symbol
.same_comdat_group
)
285 if (!pointer_set_insert (reachable
, next
))
286 enqueue_node ((symtab_node
) next
, &first
, reachable
);
288 /* Mark references as reachable. */
289 process_references (&node
->symbol
.ref_list
, &first
,
290 before_inlining_p
, reachable
);
293 if (cgraph_node
*cnode
= dyn_cast
<cgraph_node
> (node
))
295 /* Mark the callees reachable unless they are direct calls to extern
296 inline functions we decided to not inline. */
299 struct cgraph_edge
*e
;
300 for (e
= cnode
->callees
; e
; e
= e
->next_callee
)
302 if (e
->callee
->analyzed
303 && (!e
->inline_failed
304 || !DECL_EXTERNAL (e
->callee
->symbol
.decl
)
306 || before_inlining_p
))
307 pointer_set_insert (reachable
, e
->callee
);
308 enqueue_node ((symtab_node
) e
->callee
, &first
, reachable
);
311 /* When inline clone exists, mark body to be preserved so when removing
312 offline copy of the function we don't kill it. */
313 if (!cnode
->alias
&& cnode
->global
.inlined_to
)
314 pointer_set_insert (body_needed_for_clonning
, cnode
->symbol
.decl
);
317 /* For non-inline clones, force their origins to the boundary and ensure
318 that body is not removed. */
319 while (cnode
->clone_of
320 && !gimple_has_body_p (cnode
->symbol
.decl
))
322 bool noninline
= cnode
->clone_of
->symbol
.decl
!= cnode
->symbol
.decl
;
323 cnode
= cnode
->clone_of
;
326 pointer_set_insert (body_needed_for_clonning
, cnode
->symbol
.decl
);
327 enqueue_node ((symtab_node
)cnode
, &first
, reachable
);
332 /* When we see constructor of external variable, keep referred nodes in the
333 boundary. This will also hold initializers of the external vars NODE
335 varpool_node
*vnode
= dyn_cast
<varpool_node
> (node
);
337 && DECL_EXTERNAL (node
->symbol
.decl
)
342 for (int i
= 0; ipa_ref_list_reference_iterate (&node
->symbol
.ref_list
, i
, ref
); i
++)
343 enqueue_node (ref
->referred
, &first
, reachable
);
347 /* Remove unreachable functions. */
348 for (node
= cgraph_first_function (); node
; node
= next
)
350 next
= cgraph_next_function (node
);
351 if (!node
->symbol
.aux
)
354 fprintf (file
, " %s", cgraph_node_name (node
));
355 cgraph_remove_node (node
);
358 else if (!pointer_set_contains (reachable
, node
))
363 fprintf (file
, " %s", cgraph_node_name (node
));
364 cgraph_node_remove_callees (node
);
365 ipa_remove_all_references (&node
->symbol
.ref_list
);
368 if (!pointer_set_contains (body_needed_for_clonning
, node
->symbol
.decl
)
369 && (node
->local
.finalized
|| !DECL_ARTIFICIAL (node
->symbol
.decl
)))
370 cgraph_release_function_body (node
);
371 node
->analyzed
= false;
375 /* Inline clones might be kept around so their materializing allows further
376 cloning. If the function the clone is inlined into is removed, we need
377 to turn it into normal cone. */
378 FOR_EACH_FUNCTION (node
)
380 if (node
->global
.inlined_to
383 gcc_assert (node
->clones
);
384 node
->global
.inlined_to
= NULL
;
385 update_inlined_to_pointer (node
, node
);
387 node
->symbol
.aux
= NULL
;
390 /* Remove unreachable variables. */
392 fprintf (file
, "\nReclaiming variables:");
393 for (vnode
= varpool_first_variable (); vnode
; vnode
= vnext
)
395 vnext
= varpool_next_variable (vnode
);
396 if (!vnode
->symbol
.aux
)
399 fprintf (file
, " %s", varpool_node_name (vnode
));
400 varpool_remove_node (vnode
);
403 else if (!pointer_set_contains (reachable
, vnode
))
408 fprintf (file
, " %s", varpool_node_name (vnode
));
411 vnode
->analyzed
= false;
412 vnode
->symbol
.aux
= NULL
;
415 vnode
->symbol
.aux
= NULL
;
418 pointer_set_destroy (reachable
);
419 pointer_set_destroy (body_needed_for_clonning
);
421 /* Now update address_taken flags and try to promote functions to be local. */
423 fprintf (file
, "\nClearing address taken flags:");
424 FOR_EACH_DEFINED_FUNCTION (node
)
425 if (node
->symbol
.address_taken
426 && !node
->symbol
.used_from_other_partition
)
428 if (!cgraph_for_node_and_aliases (node
, has_addr_references_p
, NULL
, true))
431 fprintf (file
, " %s", cgraph_node_name (node
));
432 node
->symbol
.address_taken
= false;
434 if (cgraph_local_node_p (node
))
436 node
->local
.local
= true;
438 fprintf (file
, " (local)");
443 fprintf (file
, "\n");
445 #ifdef ENABLE_CHECKING
449 /* If we removed something, perhaps profile could be improved. */
450 if (changed
&& optimize
&& inline_edge_summary_vec
)
451 FOR_EACH_DEFINED_FUNCTION (node
)
452 cgraph_propagate_frequency (node
);
457 /* Discover variables that have no longer address taken or that are read only
458 and update their flags.
460 FIXME: This can not be done in between gimplify and omp_expand since
461 readonly flag plays role on what is shared and what is not. Currently we do
462 this transformation as part of whole program visibility and re-do at
463 ipa-reference pass (to take into account clonning), but it would
464 make sense to do it before early optimizations. */
467 ipa_discover_readonly_nonaddressable_vars (void)
469 struct varpool_node
*vnode
;
471 fprintf (dump_file
, "Clearing variable flags:");
472 FOR_EACH_VARIABLE (vnode
)
473 if (vnode
->finalized
&& varpool_all_refs_explicit_p (vnode
)
474 && (TREE_ADDRESSABLE (vnode
->symbol
.decl
)
475 || !TREE_READONLY (vnode
->symbol
.decl
)))
477 bool written
= false;
478 bool address_taken
= false;
481 for (i
= 0; ipa_ref_list_referring_iterate (&vnode
->symbol
.ref_list
,
483 && (!written
|| !address_taken
); i
++)
487 address_taken
= true;
495 if (TREE_ADDRESSABLE (vnode
->symbol
.decl
) && !address_taken
)
498 fprintf (dump_file
, " %s (addressable)", varpool_node_name (vnode
));
499 TREE_ADDRESSABLE (vnode
->symbol
.decl
) = 0;
501 if (!TREE_READONLY (vnode
->symbol
.decl
) && !address_taken
&& !written
502 /* Making variable in explicit section readonly can cause section
504 See e.g. gcc.c-torture/compile/pr23237.c */
505 && DECL_SECTION_NAME (vnode
->symbol
.decl
) == NULL
)
508 fprintf (dump_file
, " %s (read-only)", varpool_node_name (vnode
));
509 TREE_READONLY (vnode
->symbol
.decl
) = 1;
513 fprintf (dump_file
, "\n");
516 /* Return true when there is a reference to node and it is not vtable. */
518 cgraph_address_taken_from_non_vtable_p (struct cgraph_node
*node
)
522 for (i
= 0; ipa_ref_list_referring_iterate (&node
->symbol
.ref_list
,
524 if (ref
->use
== IPA_REF_ADDR
)
526 struct varpool_node
*node
;
527 if (is_a
<cgraph_node
> (ref
->referring
))
529 node
= ipa_ref_referring_varpool_node (ref
);
530 if (!DECL_VIRTUAL_P (node
->symbol
.decl
))
536 /* COMDAT functions must be shared only if they have address taken,
537 otherwise we can produce our own private implementation with
539 Return true when turning COMDAT functoin static can not lead to wrong
540 code when the resulting object links with a library defining same COMDAT.
542 Virtual functions do have their addresses taken from the vtables,
543 but in C++ there is no way to compare their addresses for equality. */
546 cgraph_comdat_can_be_unshared_p (struct cgraph_node
*node
)
548 if ((cgraph_address_taken_from_non_vtable_p (node
)
549 && !DECL_VIRTUAL_P (node
->symbol
.decl
))
552 if (node
->symbol
.same_comdat_group
)
554 struct cgraph_node
*next
;
556 /* If more than one function is in the same COMDAT group, it must
557 be shared even if just one function in the comdat group has
559 for (next
= cgraph (node
->symbol
.same_comdat_group
);
560 next
!= node
; next
= cgraph (next
->symbol
.same_comdat_group
))
561 if (cgraph_address_taken_from_non_vtable_p (next
)
562 && !DECL_VIRTUAL_P (next
->symbol
.decl
))
568 /* Return true when function NODE should be considered externally visible. */
571 cgraph_externally_visible_p (struct cgraph_node
*node
,
572 bool whole_program
, bool aliased
)
574 if (!node
->local
.finalized
)
576 if (!DECL_COMDAT (node
->symbol
.decl
)
577 && (!TREE_PUBLIC (node
->symbol
.decl
)
578 || DECL_EXTERNAL (node
->symbol
.decl
)))
581 /* Do not even try to be smart about aliased nodes. Until we properly
582 represent everything by same body alias, these are just evil. */
586 /* Do not try to localize built-in functions yet. One of problems is that we
587 end up mangling their asm for WHOPR that makes it impossible to call them
588 using the implicit built-in declarations anymore. Similarly this enables
589 us to remove them as unreachable before actual calls may appear during
590 expansion or folding. */
591 if (DECL_BUILT_IN (node
->symbol
.decl
))
594 /* If linker counts on us, we must preserve the function. */
595 if (symtab_used_from_object_file_p ((symtab_node
) node
))
597 if (DECL_PRESERVE_P (node
->symbol
.decl
))
599 if (lookup_attribute ("externally_visible",
600 DECL_ATTRIBUTES (node
->symbol
.decl
)))
602 if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
603 && lookup_attribute ("dllexport",
604 DECL_ATTRIBUTES (node
->symbol
.decl
)))
606 if (node
->symbol
.resolution
== LDPR_PREVAILING_DEF_IRONLY
)
608 /* When doing LTO or whole program, we can bring COMDAT functoins static.
609 This improves code quality and we know we will duplicate them at most twice
610 (in the case that we are not using plugin and link with object file
611 implementing same COMDAT) */
612 if ((in_lto_p
|| whole_program
)
613 && DECL_COMDAT (node
->symbol
.decl
)
614 && cgraph_comdat_can_be_unshared_p (node
))
617 /* When doing link time optimizations, hidden symbols become local. */
619 && (DECL_VISIBILITY (node
->symbol
.decl
) == VISIBILITY_HIDDEN
620 || DECL_VISIBILITY (node
->symbol
.decl
) == VISIBILITY_INTERNAL
)
621 /* Be sure that node is defined in IR file, not in other object
622 file. In that case we don't set used_from_other_object_file. */
625 else if (!whole_program
)
628 if (MAIN_NAME_P (DECL_NAME (node
->symbol
.decl
)))
634 /* Return true when variable VNODE should be considered externally visible. */
637 varpool_externally_visible_p (struct varpool_node
*vnode
, bool aliased
)
639 /* Do not touch weakrefs; while they are not externally visible,
640 dropping their DECL_EXTERNAL flags confuse most
641 of code handling them. */
642 if (vnode
->alias
&& DECL_EXTERNAL (vnode
->symbol
.decl
))
645 if (DECL_EXTERNAL (vnode
->symbol
.decl
))
648 if (!DECL_COMDAT (vnode
->symbol
.decl
) && !TREE_PUBLIC (vnode
->symbol
.decl
))
651 /* Do not even try to be smart about aliased nodes. Until we properly
652 represent everything by same body alias, these are just evil. */
656 /* If linker counts on us, we must preserve the function. */
657 if (symtab_used_from_object_file_p ((symtab_node
) vnode
))
660 if (DECL_HARD_REGISTER (vnode
->symbol
.decl
))
662 if (DECL_PRESERVE_P (vnode
->symbol
.decl
))
664 if (lookup_attribute ("externally_visible",
665 DECL_ATTRIBUTES (vnode
->symbol
.decl
)))
667 if (TARGET_DLLIMPORT_DECL_ATTRIBUTES
668 && lookup_attribute ("dllexport",
669 DECL_ATTRIBUTES (vnode
->symbol
.decl
)))
672 /* See if we have linker information about symbol not being used or
673 if we need to make guess based on the declaration.
675 Even if the linker clams the symbol is unused, never bring internal
676 symbols that are declared by user as used or externally visible.
677 This is needed for i.e. references from asm statements. */
678 if (symtab_used_from_object_file_p ((symtab_node
) vnode
))
680 if (vnode
->symbol
.resolution
== LDPR_PREVAILING_DEF_IRONLY
)
683 /* As a special case, the COMDAT virtual tables can be unshared.
684 In LTO mode turn vtables into static variables. The variable is readonly,
685 so this does not enable more optimization, but referring static var
686 is faster for dynamic linking. Also this match logic hidding vtables
687 from LTO symbol tables. */
688 if ((in_lto_p
|| flag_whole_program
)
689 && !vnode
->symbol
.force_output
690 && DECL_COMDAT (vnode
->symbol
.decl
) && DECL_VIRTUAL_P (vnode
->symbol
.decl
))
693 /* When doing link time optimizations, hidden symbols become local. */
695 && (DECL_VISIBILITY (vnode
->symbol
.decl
) == VISIBILITY_HIDDEN
696 || DECL_VISIBILITY (vnode
->symbol
.decl
) == VISIBILITY_INTERNAL
)
697 /* Be sure that node is defined in IR file, not in other object
698 file. In that case we don't set used_from_other_object_file. */
701 else if (!flag_whole_program
)
704 /* Do not attempt to privatize COMDATS by default.
705 This would break linking with C++ libraries sharing
708 FIXME: We can do so for readonly vars with no address taken and
709 possibly also for vtables since no direct pointer comparsion is done.
710 It might be interesting to do so to reduce linking overhead. */
711 if (DECL_COMDAT (vnode
->symbol
.decl
) || DECL_WEAK (vnode
->symbol
.decl
))
716 /* Mark visibility of all functions.
718 A local function is one whose calls can occur only in the current
719 compilation unit and all its calls are explicit, so we can change
720 its calling convention. We simply mark all static functions whose
721 address is not taken as local.
723 We also change the TREE_PUBLIC flag of all declarations that are public
724 in language point of view but we want to overwrite this default
725 via visibilities for the backend point of view. */
728 function_and_variable_visibility (bool whole_program
)
730 struct cgraph_node
*node
;
731 struct varpool_node
*vnode
;
732 struct pointer_set_t
*aliased_nodes
= pointer_set_create ();
733 struct pointer_set_t
*aliased_vnodes
= pointer_set_create ();
737 /* Discover aliased nodes. */
738 FOR_EACH_VEC_ELT (alias_pair
, alias_pairs
, i
, p
)
741 fprintf (dump_file
, "Alias %s->%s",
742 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (p
->decl
)),
743 IDENTIFIER_POINTER (p
->target
));
745 if ((node
= cgraph_node_for_asm (p
->target
)) != NULL
746 && !DECL_EXTERNAL (node
->symbol
.decl
))
750 cgraph_mark_force_output_node (node
);
751 pointer_set_insert (aliased_nodes
, node
);
753 fprintf (dump_file
, " node %s/%i",
754 cgraph_node_name (node
), node
->uid
);
756 else if ((vnode
= varpool_node_for_asm (p
->target
)) != NULL
757 && !DECL_EXTERNAL (vnode
->symbol
.decl
))
759 vnode
->symbol
.force_output
= 1;
760 pointer_set_insert (aliased_vnodes
, vnode
);
762 fprintf (dump_file
, " varpool node %s",
763 varpool_node_name (vnode
));
766 fprintf (dump_file
, "\n");
769 FOR_EACH_FUNCTION (node
)
771 int flags
= flags_from_decl_or_type (node
->symbol
.decl
);
773 /* Optimize away PURE and CONST constructors and destructors. */
775 && (flags
& (ECF_CONST
| ECF_PURE
))
776 && !(flags
& ECF_LOOPING_CONST_OR_PURE
))
778 DECL_STATIC_CONSTRUCTOR (node
->symbol
.decl
) = 0;
779 DECL_STATIC_DESTRUCTOR (node
->symbol
.decl
) = 0;
782 /* Frontends and alias code marks nodes as needed before parsing is finished.
783 We may end up marking as node external nodes where this flag is meaningless
785 if (node
->symbol
.force_output
786 && (DECL_EXTERNAL (node
->symbol
.decl
) || !node
->analyzed
))
787 node
->symbol
.force_output
= 0;
789 /* C++ FE on lack of COMDAT support create local COMDAT functions
790 (that ought to be shared but can not due to object format
791 limitations). It is necessary to keep the flag to make rest of C++ FE
792 happy. Clear the flag here to avoid confusion in middle-end. */
793 if (DECL_COMDAT (node
->symbol
.decl
) && !TREE_PUBLIC (node
->symbol
.decl
))
794 DECL_COMDAT (node
->symbol
.decl
) = 0;
795 /* For external decls stop tracking same_comdat_group, it doesn't matter
796 what comdat group they are in when they won't be emitted in this TU,
797 and simplifies later passes. */
798 if (node
->symbol
.same_comdat_group
&& DECL_EXTERNAL (node
->symbol
.decl
))
800 #ifdef ENABLE_CHECKING
803 for (n
= node
->symbol
.same_comdat_group
;
804 n
!= (symtab_node
)node
;
805 n
= n
->symbol
.same_comdat_group
)
806 /* If at least one of same comdat group functions is external,
807 all of them have to be, otherwise it is a front-end bug. */
808 gcc_assert (DECL_EXTERNAL (n
->symbol
.decl
));
810 symtab_dissolve_same_comdat_group_list ((symtab_node
) node
);
812 gcc_assert ((!DECL_WEAK (node
->symbol
.decl
)
813 && !DECL_COMDAT (node
->symbol
.decl
))
814 || TREE_PUBLIC (node
->symbol
.decl
)
815 || DECL_EXTERNAL (node
->symbol
.decl
));
816 if (cgraph_externally_visible_p (node
, whole_program
,
817 pointer_set_contains (aliased_nodes
,
820 gcc_assert (!node
->global
.inlined_to
);
821 node
->symbol
.externally_visible
= true;
824 node
->symbol
.externally_visible
= false;
825 if (!node
->symbol
.externally_visible
&& node
->analyzed
826 && !DECL_EXTERNAL (node
->symbol
.decl
))
828 gcc_assert (whole_program
|| in_lto_p
829 || !TREE_PUBLIC (node
->symbol
.decl
));
830 symtab_make_decl_local (node
->symbol
.decl
);
831 node
->symbol
.resolution
= LDPR_PREVAILING_DEF_IRONLY
;
832 if (node
->symbol
.same_comdat_group
)
833 /* cgraph_externally_visible_p has already checked all other nodes
834 in the group and they will all be made local. We need to
835 dissolve the group at once so that the predicate does not
837 symtab_dissolve_same_comdat_group_list ((symtab_node
) node
);
840 if (node
->thunk
.thunk_p
841 && TREE_PUBLIC (node
->symbol
.decl
))
843 struct cgraph_node
*decl_node
= node
;
845 decl_node
= cgraph_function_node (decl_node
->callees
->callee
, NULL
);
847 /* Thunks have the same visibility as function they are attached to.
848 Make sure the C++ front end set this up properly. */
849 if (DECL_ONE_ONLY (decl_node
->symbol
.decl
))
851 gcc_checking_assert (DECL_COMDAT (node
->symbol
.decl
)
852 == DECL_COMDAT (decl_node
->symbol
.decl
));
853 gcc_checking_assert (DECL_COMDAT_GROUP (node
->symbol
.decl
)
854 == DECL_COMDAT_GROUP (decl_node
->symbol
.decl
));
855 gcc_checking_assert (node
->symbol
.same_comdat_group
);
857 if (DECL_EXTERNAL (decl_node
->symbol
.decl
))
858 DECL_EXTERNAL (node
->symbol
.decl
) = 1;
861 FOR_EACH_DEFINED_FUNCTION (node
)
862 node
->local
.local
= cgraph_local_node_p (node
);
863 FOR_EACH_VARIABLE (vnode
)
865 /* weak flag makes no sense on local variables. */
866 gcc_assert (!DECL_WEAK (vnode
->symbol
.decl
)
867 || TREE_PUBLIC (vnode
->symbol
.decl
)
868 || DECL_EXTERNAL (vnode
->symbol
.decl
));
869 /* In several cases declarations can not be common:
871 - when declaration has initializer
873 - when it has specific section
874 - when it resides in non-generic address space.
875 - if declaration is local, it will get into .local common section
876 so common flag is not needed. Frontends still produce these in
877 certain cases, such as for:
879 static int a __attribute__ ((common))
881 Canonicalize things here and clear the redundant flag. */
882 if (DECL_COMMON (vnode
->symbol
.decl
)
883 && (!(TREE_PUBLIC (vnode
->symbol
.decl
)
884 || DECL_EXTERNAL (vnode
->symbol
.decl
))
885 || (DECL_INITIAL (vnode
->symbol
.decl
)
886 && DECL_INITIAL (vnode
->symbol
.decl
) != error_mark_node
)
887 || DECL_WEAK (vnode
->symbol
.decl
)
888 || DECL_SECTION_NAME (vnode
->symbol
.decl
) != NULL
889 || ! (ADDR_SPACE_GENERIC_P
890 (TYPE_ADDR_SPACE (TREE_TYPE (vnode
->symbol
.decl
))))))
891 DECL_COMMON (vnode
->symbol
.decl
) = 0;
893 FOR_EACH_DEFINED_VARIABLE (vnode
)
895 if (!vnode
->finalized
)
897 if (varpool_externally_visible_p
899 pointer_set_contains (aliased_vnodes
, vnode
)))
900 vnode
->symbol
.externally_visible
= true;
902 vnode
->symbol
.externally_visible
= false;
903 if (!vnode
->symbol
.externally_visible
)
905 gcc_assert (in_lto_p
|| whole_program
|| !TREE_PUBLIC (vnode
->symbol
.decl
));
906 symtab_make_decl_local (vnode
->symbol
.decl
);
907 if (vnode
->symbol
.same_comdat_group
)
908 symtab_dissolve_same_comdat_group_list ((symtab_node
) vnode
);
909 vnode
->symbol
.resolution
= LDPR_PREVAILING_DEF_IRONLY
;
912 pointer_set_destroy (aliased_nodes
);
913 pointer_set_destroy (aliased_vnodes
);
917 fprintf (dump_file
, "\nMarking local functions:");
918 FOR_EACH_DEFINED_FUNCTION (node
)
919 if (node
->local
.local
)
920 fprintf (dump_file
, " %s", cgraph_node_name (node
));
921 fprintf (dump_file
, "\n\n");
922 fprintf (dump_file
, "\nMarking externally visible functions:");
923 FOR_EACH_DEFINED_FUNCTION (node
)
924 if (node
->symbol
.externally_visible
)
925 fprintf (dump_file
, " %s", cgraph_node_name (node
));
926 fprintf (dump_file
, "\n\n");
927 fprintf (dump_file
, "\nMarking externally visible variables:");
928 FOR_EACH_DEFINED_VARIABLE (vnode
)
929 if (vnode
->symbol
.externally_visible
)
930 fprintf (dump_file
, " %s", varpool_node_name (vnode
));
931 fprintf (dump_file
, "\n\n");
933 cgraph_function_flags_ready
= true;
937 /* Local function pass handling visibilities. This happens before LTO streaming
938 so in particular -fwhole-program should be ignored at this level. */
941 local_function_and_variable_visibility (void)
943 return function_and_variable_visibility (flag_whole_program
&& !flag_lto
);
946 struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility
=
950 "visibility", /* name */
951 OPTGROUP_NONE
, /* optinfo_flags */
953 local_function_and_variable_visibility
,/* execute */
956 0, /* static_pass_number */
957 TV_CGRAPHOPT
, /* tv_id */
958 0, /* properties_required */
959 0, /* properties_provided */
960 0, /* properties_destroyed */
961 0, /* todo_flags_start */
962 TODO_remove_functions
| TODO_dump_symtab
963 | TODO_ggc_collect
/* todo_flags_finish */
967 /* Free inline summary. */
970 free_inline_summary (void)
972 inline_free_summary ();
976 struct simple_ipa_opt_pass pass_ipa_free_inline_summary
=
980 "*free_inline_summary", /* name */
981 OPTGROUP_NONE
, /* optinfo_flags */
983 free_inline_summary
, /* execute */
986 0, /* static_pass_number */
987 TV_IPA_FREE_INLINE_SUMMARY
, /* tv_id */
988 0, /* properties_required */
989 0, /* properties_provided */
990 0, /* properties_destroyed */
991 0, /* todo_flags_start */
992 TODO_ggc_collect
/* todo_flags_finish */
996 /* Do not re-run on ltrans stage. */
999 gate_whole_program_function_and_variable_visibility (void)
1001 return !flag_ltrans
;
1004 /* Bring functionss local at LTO time with -fwhole-program. */
1007 whole_program_function_and_variable_visibility (void)
1009 function_and_variable_visibility (flag_whole_program
);
1011 ipa_discover_readonly_nonaddressable_vars ();
1015 struct ipa_opt_pass_d pass_ipa_whole_program_visibility
=
1019 "whole-program", /* name */
1020 OPTGROUP_NONE
, /* optinfo_flags */
1021 gate_whole_program_function_and_variable_visibility
,/* gate */
1022 whole_program_function_and_variable_visibility
,/* execute */
1025 0, /* static_pass_number */
1026 TV_CGRAPHOPT
, /* tv_id */
1027 0, /* properties_required */
1028 0, /* properties_provided */
1029 0, /* properties_destroyed */
1030 0, /* todo_flags_start */
1031 TODO_remove_functions
| TODO_dump_symtab
1032 | TODO_ggc_collect
/* todo_flags_finish */
1034 NULL
, /* generate_summary */
1035 NULL
, /* write_summary */
1036 NULL
, /* read_summary */
1037 NULL
, /* write_optimization_summary */
1038 NULL
, /* read_optimization_summary */
1039 NULL
, /* stmt_fixup */
1041 NULL
, /* function_transform */
1042 NULL
, /* variable_transform */
1046 /* Simple ipa profile pass propagating frequencies across the callgraph. */
1051 struct cgraph_node
**order
= XCNEWVEC (struct cgraph_node
*, cgraph_n_nodes
);
1052 struct cgraph_edge
*e
;
1054 bool something_changed
= false;
1057 order_pos
= ipa_reverse_postorder (order
);
1058 for (i
= order_pos
- 1; i
>= 0; i
--)
1060 if (order
[i
]->local
.local
&& cgraph_propagate_frequency (order
[i
]))
1062 for (e
= order
[i
]->callees
; e
; e
= e
->next_callee
)
1063 if (e
->callee
->local
.local
&& !e
->callee
->symbol
.aux
)
1065 something_changed
= true;
1066 e
->callee
->symbol
.aux
= (void *)1;
1069 order
[i
]->symbol
.aux
= NULL
;
1072 while (something_changed
)
1074 something_changed
= false;
1075 for (i
= order_pos
- 1; i
>= 0; i
--)
1077 if (order
[i
]->symbol
.aux
&& cgraph_propagate_frequency (order
[i
]))
1079 for (e
= order
[i
]->callees
; e
; e
= e
->next_callee
)
1080 if (e
->callee
->local
.local
&& !e
->callee
->symbol
.aux
)
1082 something_changed
= true;
1083 e
->callee
->symbol
.aux
= (void *)1;
1086 order
[i
]->symbol
.aux
= NULL
;
1094 gate_ipa_profile (void)
1096 return flag_ipa_profile
;
1099 struct ipa_opt_pass_d pass_ipa_profile
=
1103 "profile_estimate", /* name */
1104 OPTGROUP_NONE
, /* optinfo_flags */
1105 gate_ipa_profile
, /* gate */
1106 ipa_profile
, /* execute */
1109 0, /* static_pass_number */
1110 TV_IPA_PROFILE
, /* tv_id */
1111 0, /* properties_required */
1112 0, /* properties_provided */
1113 0, /* properties_destroyed */
1114 0, /* todo_flags_start */
1115 0 /* todo_flags_finish */
1117 NULL
, /* generate_summary */
1118 NULL
, /* write_summary */
1119 NULL
, /* read_summary */
1120 NULL
, /* write_optimization_summary */
1121 NULL
, /* read_optimization_summary */
1122 NULL
, /* stmt_fixup */
1124 NULL
, /* function_transform */
1125 NULL
/* variable_transform */
1128 /* Generate and emit a static constructor or destructor. WHICH must
1129 be one of 'I' (for a constructor) or 'D' (for a destructor). BODY
1130 is a STATEMENT_LIST containing GENERIC statements. PRIORITY is the
1131 initialization priority for this constructor or destructor.
1133 FINAL specify whether the externally visible name for collect2 should
1137 cgraph_build_static_cdtor_1 (char which
, tree body
, int priority
, bool final
)
1139 static int counter
= 0;
1141 tree decl
, name
, resdecl
;
1143 /* The priority is encoded in the constructor or destructor name.
1144 collect2 will sort the names and arrange that they are called at
1147 sprintf (which_buf
, "%c_%.5d_%d", which
, priority
, counter
++);
1149 /* Proudce sane name but one not recognizable by collect2, just for the
1150 case we fail to inline the function. */
1151 sprintf (which_buf
, "sub_%c_%.5d_%d", which
, priority
, counter
++);
1152 name
= get_file_function_name (which_buf
);
1154 decl
= build_decl (input_location
, FUNCTION_DECL
, name
,
1155 build_function_type_list (void_type_node
, NULL_TREE
));
1156 current_function_decl
= decl
;
1158 resdecl
= build_decl (input_location
,
1159 RESULT_DECL
, NULL_TREE
, void_type_node
);
1160 DECL_ARTIFICIAL (resdecl
) = 1;
1161 DECL_RESULT (decl
) = resdecl
;
1162 DECL_CONTEXT (resdecl
) = decl
;
1164 allocate_struct_function (decl
, false);
1166 TREE_STATIC (decl
) = 1;
1167 TREE_USED (decl
) = 1;
1168 DECL_ARTIFICIAL (decl
) = 1;
1169 DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl
) = 1;
1170 DECL_SAVED_TREE (decl
) = body
;
1171 if (!targetm
.have_ctors_dtors
&& final
)
1173 TREE_PUBLIC (decl
) = 1;
1174 DECL_PRESERVE_P (decl
) = 1;
1176 DECL_UNINLINABLE (decl
) = 1;
1178 DECL_INITIAL (decl
) = make_node (BLOCK
);
1179 TREE_USED (DECL_INITIAL (decl
)) = 1;
1181 DECL_SOURCE_LOCATION (decl
) = input_location
;
1182 cfun
->function_end_locus
= input_location
;
1187 DECL_STATIC_CONSTRUCTOR (decl
) = 1;
1188 decl_init_priority_insert (decl
, priority
);
1191 DECL_STATIC_DESTRUCTOR (decl
) = 1;
1192 decl_fini_priority_insert (decl
, priority
);
1198 gimplify_function_tree (decl
);
1200 cgraph_add_new_function (decl
, false);
1203 current_function_decl
= NULL
;
1206 /* Generate and emit a static constructor or destructor. WHICH must
1207 be one of 'I' (for a constructor) or 'D' (for a destructor). BODY
1208 is a STATEMENT_LIST containing GENERIC statements. PRIORITY is the
1209 initialization priority for this constructor or destructor. */
1212 cgraph_build_static_cdtor (char which
, tree body
, int priority
)
1214 cgraph_build_static_cdtor_1 (which
, body
, priority
, false);
1217 /* A vector of FUNCTION_DECLs declared as static constructors. */
1218 static VEC(tree
, heap
) *static_ctors
;
1219 /* A vector of FUNCTION_DECLs declared as static destructors. */
1220 static VEC(tree
, heap
) *static_dtors
;
1222 /* When target does not have ctors and dtors, we call all constructor
1223 and destructor by special initialization/destruction function
1224 recognized by collect2.
1226 When we are going to build this function, collect all constructors and
1227 destructors and turn them into normal functions. */
1230 record_cdtor_fn (struct cgraph_node
*node
)
1232 if (DECL_STATIC_CONSTRUCTOR (node
->symbol
.decl
))
1233 VEC_safe_push (tree
, heap
, static_ctors
, node
->symbol
.decl
);
1234 if (DECL_STATIC_DESTRUCTOR (node
->symbol
.decl
))
1235 VEC_safe_push (tree
, heap
, static_dtors
, node
->symbol
.decl
);
1236 node
= cgraph_get_node (node
->symbol
.decl
);
1237 DECL_DISREGARD_INLINE_LIMITS (node
->symbol
.decl
) = 1;
1240 /* Define global constructors/destructor functions for the CDTORS, of
1241 which they are LEN. The CDTORS are sorted by initialization
1242 priority. If CTOR_P is true, these are constructors; otherwise,
1243 they are destructors. */
1246 build_cdtor (bool ctor_p
, VEC (tree
, heap
) *cdtors
)
1249 size_t len
= VEC_length (tree
, cdtors
);
1256 priority_type priority
;
1264 fn
= VEC_index (tree
, cdtors
, j
);
1265 p
= ctor_p
? DECL_INIT_PRIORITY (fn
) : DECL_FINI_PRIORITY (fn
);
1268 else if (p
!= priority
)
1274 /* When there is only one cdtor and target supports them, do nothing. */
1276 && targetm
.have_ctors_dtors
)
1281 /* Find the next batch of constructors/destructors with the same
1282 initialization priority. */
1286 fn
= VEC_index (tree
, cdtors
, i
);
1287 call
= build_call_expr (fn
, 0);
1289 DECL_STATIC_CONSTRUCTOR (fn
) = 0;
1291 DECL_STATIC_DESTRUCTOR (fn
) = 0;
1292 /* We do not want to optimize away pure/const calls here.
1293 When optimizing, these should be already removed, when not
1294 optimizing, we want user to be able to breakpoint in them. */
1295 TREE_SIDE_EFFECTS (call
) = 1;
1296 append_to_statement_list (call
, &body
);
1298 gcc_assert (body
!= NULL_TREE
);
1299 /* Generate a function to call all the function of like
1301 cgraph_build_static_cdtor_1 (ctor_p
? 'I' : 'D', body
, priority
, true);
1305 /* Comparison function for qsort. P1 and P2 are actually of type
1306 "tree *" and point to static constructors. DECL_INIT_PRIORITY is
1307 used to determine the sort order. */
1310 compare_ctor (const void *p1
, const void *p2
)
1317 f1
= *(const tree
*)p1
;
1318 f2
= *(const tree
*)p2
;
1319 priority1
= DECL_INIT_PRIORITY (f1
);
1320 priority2
= DECL_INIT_PRIORITY (f2
);
1322 if (priority1
< priority2
)
1324 else if (priority1
> priority2
)
1327 /* Ensure a stable sort. Constructors are executed in backwarding
1328 order to make LTO initialize braries first. */
1329 return DECL_UID (f2
) - DECL_UID (f1
);
1332 /* Comparison function for qsort. P1 and P2 are actually of type
1333 "tree *" and point to static destructors. DECL_FINI_PRIORITY is
1334 used to determine the sort order. */
1337 compare_dtor (const void *p1
, const void *p2
)
1344 f1
= *(const tree
*)p1
;
1345 f2
= *(const tree
*)p2
;
1346 priority1
= DECL_FINI_PRIORITY (f1
);
1347 priority2
= DECL_FINI_PRIORITY (f2
);
1349 if (priority1
< priority2
)
1351 else if (priority1
> priority2
)
1354 /* Ensure a stable sort. */
1355 return DECL_UID (f1
) - DECL_UID (f2
);
1358 /* Generate functions to call static constructors and destructors
1359 for targets that do not support .ctors/.dtors sections. These
1360 functions have magic names which are detected by collect2. */
1363 build_cdtor_fns (void)
1365 if (!VEC_empty (tree
, static_ctors
))
1367 gcc_assert (!targetm
.have_ctors_dtors
|| in_lto_p
);
1368 VEC_qsort (tree
, static_ctors
, compare_ctor
);
1369 build_cdtor (/*ctor_p=*/true, static_ctors
);
1372 if (!VEC_empty (tree
, static_dtors
))
1374 gcc_assert (!targetm
.have_ctors_dtors
|| in_lto_p
);
1375 VEC_qsort (tree
, static_dtors
, compare_dtor
);
1376 build_cdtor (/*ctor_p=*/false, static_dtors
);
1380 /* Look for constructors and destructors and produce function calling them.
1381 This is needed for targets not supporting ctors or dtors, but we perform the
1382 transformation also at linktime to merge possibly numerous
1383 constructors/destructors into single function to improve code locality and
1387 ipa_cdtor_merge (void)
1389 struct cgraph_node
*node
;
1390 FOR_EACH_DEFINED_FUNCTION (node
)
1391 if (DECL_STATIC_CONSTRUCTOR (node
->symbol
.decl
)
1392 || DECL_STATIC_DESTRUCTOR (node
->symbol
.decl
))
1393 record_cdtor_fn (node
);
1395 VEC_free (tree
, heap
, static_ctors
);
1396 VEC_free (tree
, heap
, static_dtors
);
1400 /* Perform the pass when we have no ctors/dtors support
1401 or at LTO time to merge multiple constructors into single
1405 gate_ipa_cdtor_merge (void)
1407 return !targetm
.have_ctors_dtors
|| (optimize
&& in_lto_p
);
1410 struct ipa_opt_pass_d pass_ipa_cdtor_merge
=
1415 OPTGROUP_NONE
, /* optinfo_flags */
1416 gate_ipa_cdtor_merge
, /* gate */
1417 ipa_cdtor_merge
, /* execute */
1420 0, /* static_pass_number */
1421 TV_CGRAPHOPT
, /* tv_id */
1422 0, /* properties_required */
1423 0, /* properties_provided */
1424 0, /* properties_destroyed */
1425 0, /* todo_flags_start */
1426 0 /* todo_flags_finish */
1428 NULL
, /* generate_summary */
1429 NULL
, /* write_summary */
1430 NULL
, /* read_summary */
1431 NULL
, /* write_optimization_summary */
1432 NULL
, /* read_optimization_summary */
1433 NULL
, /* stmt_fixup */
1435 NULL
, /* function_transform */
1436 NULL
/* variable_transform */