1 /* Basic IPA optimizations and utilities.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010
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"
31 /* Fill array order with all nodes with output flag set in the reverse
35 cgraph_postorder (struct cgraph_node
**order
)
37 struct cgraph_node
*node
, *node2
;
40 struct cgraph_edge
*edge
, last
;
43 struct cgraph_node
**stack
=
44 XCNEWVEC (struct cgraph_node
*, cgraph_n_nodes
);
46 /* We have to deal with cycles nicely, so use a depth first traversal
47 output algorithm. Ignore the fact that some functions won't need
48 to be output and put them into order as well, so we get dependencies
49 right through inline functions. */
50 for (node
= cgraph_nodes
; node
; node
= node
->next
)
52 for (pass
= 0; pass
< 2; pass
++)
53 for (node
= cgraph_nodes
; node
; node
= node
->next
)
56 || (!cgraph_only_called_directly_p (node
)
57 && !node
->address_taken
)))
63 node
->aux
= node
->callers
;
66 while (node2
->aux
!= &last
)
68 edge
= (struct cgraph_edge
*) node2
->aux
;
69 if (edge
->next_caller
)
70 node2
->aux
= edge
->next_caller
;
73 /* Break possible cycles involving always-inline
74 functions by ignoring edges from always-inline
75 functions to non-always-inline functions. */
76 if (edge
->caller
->local
.disregard_inline_limits
77 && !edge
->callee
->local
.disregard_inline_limits
)
79 if (!edge
->caller
->aux
)
81 if (!edge
->caller
->callers
)
82 edge
->caller
->aux
= &last
;
84 edge
->caller
->aux
= edge
->caller
->callers
;
85 stack
[stack_size
++] = node2
;
90 if (node2
->aux
== &last
)
92 order
[order_pos
++] = node2
;
94 node2
= stack
[--stack_size
];
101 for (node
= cgraph_nodes
; node
; node
= node
->next
)
106 /* Look for all functions inlined to NODE and update their inlined_to pointers
110 update_inlined_to_pointer (struct cgraph_node
*node
, struct cgraph_node
*inlined_to
)
112 struct cgraph_edge
*e
;
113 for (e
= node
->callees
; e
; e
= e
->next_callee
)
114 if (e
->callee
->global
.inlined_to
)
116 e
->callee
->global
.inlined_to
= inlined_to
;
117 update_inlined_to_pointer (e
->callee
, inlined_to
);
121 /* Perform reachability analysis and reclaim all unreachable nodes.
122 If BEFORE_INLINING_P is true this function is called before inlining
123 decisions has been made. If BEFORE_INLINING_P is false this function also
124 removes unneeded bodies of extern inline functions. */
127 cgraph_remove_unreachable_nodes (bool before_inlining_p
, FILE *file
)
129 struct cgraph_node
*first
= (struct cgraph_node
*) (void *) 1;
130 struct cgraph_node
*processed
= (struct cgraph_node
*) (void *) 2;
131 struct cgraph_node
*node
, *next
;
132 bool changed
= false;
134 #ifdef ENABLE_CHECKING
138 fprintf (file
, "\nReclaiming functions:");
139 #ifdef ENABLE_CHECKING
140 for (node
= cgraph_nodes
; node
; node
= node
->next
)
141 gcc_assert (!node
->aux
);
143 for (node
= cgraph_nodes
; node
; node
= node
->next
)
144 if (!cgraph_can_remove_if_no_direct_calls_p (node
)
145 && ((!DECL_EXTERNAL (node
->decl
))
147 || before_inlining_p
))
149 gcc_assert (!node
->global
.inlined_to
);
152 node
->reachable
= true;
156 gcc_assert (!node
->aux
);
157 node
->reachable
= false;
160 /* Perform reachability analysis. As a special case do not consider
161 extern inline functions not inlined as live because we won't output
163 while (first
!= (void *) 1)
165 struct cgraph_edge
*e
;
167 first
= (struct cgraph_node
*) first
->aux
;
168 node
->aux
= processed
;
171 for (e
= node
->callees
; e
; e
= e
->next_callee
)
172 if (!e
->callee
->reachable
174 && (!e
->inline_failed
|| !e
->callee
->analyzed
175 || (!DECL_EXTERNAL (e
->callee
->decl
))
176 || before_inlining_p
))
178 bool prev_reachable
= e
->callee
->reachable
;
179 e
->callee
->reachable
|= node
->reachable
;
181 || (e
->callee
->aux
== processed
182 && prev_reachable
!= e
->callee
->reachable
))
184 e
->callee
->aux
= first
;
189 /* If any function in a comdat group is reachable, force
190 all other functions in the same comdat group to be
192 if (node
->same_comdat_group
194 && !node
->global
.inlined_to
)
196 for (next
= node
->same_comdat_group
;
198 next
= next
->same_comdat_group
)
199 if (!next
->reachable
)
203 next
->reachable
= true;
207 /* We can freely remove inline clones even if they are cloned, however if
208 function is clone of real clone, we must keep it around in order to
209 make materialize_clones produce function body with the changes
211 while (node
->clone_of
&& !node
->clone_of
->aux
&& !gimple_has_body_p (node
->decl
))
213 bool noninline
= node
->clone_of
->decl
!= node
->decl
;
214 node
= node
->clone_of
;
224 /* Remove unreachable nodes. Extern inline functions need special care;
225 Unreachable extern inline functions shall be removed.
226 Reachable extern inline functions we never inlined shall get their bodies
228 Reachable extern inline functions we sometimes inlined will be turned into
229 unanalyzed nodes so they look like for true extern functions to the rest
230 of code. Body of such functions is released via remove_node once the
231 inline clones are eliminated. */
232 for (node
= cgraph_nodes
; node
; node
= next
)
235 if (node
->aux
&& !node
->reachable
)
237 cgraph_node_remove_callees (node
);
238 node
->analyzed
= false;
239 node
->local
.inlinable
= false;
243 node
->global
.inlined_to
= NULL
;
245 fprintf (file
, " %s", cgraph_node_name (node
));
246 if (!node
->analyzed
|| !DECL_EXTERNAL (node
->decl
) || before_inlining_p
)
247 cgraph_remove_node (node
);
250 struct cgraph_edge
*e
;
252 /* See if there is reachable caller. */
253 for (e
= node
->callers
; e
; e
= e
->next_caller
)
257 /* If so, we need to keep node in the callgraph. */
258 if (e
|| node
->needed
)
260 struct cgraph_node
*clone
;
262 /* If there are still clones, we must keep body around.
263 Otherwise we can just remove the body but keep the clone. */
264 for (clone
= node
->clones
; clone
;
265 clone
= clone
->next_sibling_clone
)
270 cgraph_release_function_body (node
);
271 node
->analyzed
= false;
272 node
->local
.inlinable
= false;
275 gcc_assert (!clone
->in_other_partition
);
276 cgraph_node_remove_callees (node
);
277 if (node
->prev_sibling_clone
)
278 node
->prev_sibling_clone
->next_sibling_clone
= node
->next_sibling_clone
;
279 else if (node
->clone_of
)
280 node
->clone_of
->clones
= node
->next_sibling_clone
;
281 if (node
->next_sibling_clone
)
282 node
->next_sibling_clone
->prev_sibling_clone
= node
->prev_sibling_clone
;
283 node
->clone_of
= NULL
;
284 node
->next_sibling_clone
= NULL
;
285 node
->prev_sibling_clone
= NULL
;
288 cgraph_remove_node (node
);
293 for (node
= cgraph_nodes
; node
; node
= node
->next
)
295 /* Inline clones might be kept around so their materializing allows further
296 cloning. If the function the clone is inlined into is removed, we need
297 to turn it into normal cone. */
298 if (node
->global
.inlined_to
301 gcc_assert (node
->clones
);
302 node
->global
.inlined_to
= NULL
;
303 update_inlined_to_pointer (node
, node
);
307 #ifdef ENABLE_CHECKING
311 /* Reclaim alias pairs for functions that have disappeared from the
313 remove_unreachable_alias_pairs ();
319 cgraph_externally_visible_p (struct cgraph_node
*node
, bool whole_program
)
321 if (!node
->local
.finalized
)
323 if (!DECL_COMDAT (node
->decl
)
324 && (!TREE_PUBLIC (node
->decl
) || DECL_EXTERNAL (node
->decl
)))
328 if (DECL_PRESERVE_P (node
->decl
))
330 /* COMDAT functions must be shared only if they have address taken,
331 otherwise we can produce our own private implementation with
333 if (DECL_COMDAT (node
->decl
))
335 if (node
->address_taken
|| !node
->analyzed
)
337 if (node
->same_comdat_group
)
339 struct cgraph_node
*next
;
341 /* If more than one function is in the same COMDAT group, it must
342 be shared even if just one function in the comdat group has
344 for (next
= node
->same_comdat_group
;
346 next
= next
->same_comdat_group
)
347 if (next
->address_taken
|| !next
->analyzed
)
351 if (MAIN_NAME_P (DECL_NAME (node
->decl
)))
353 if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (node
->decl
)))
358 /* Mark visibility of all functions.
360 A local function is one whose calls can occur only in the current
361 compilation unit and all its calls are explicit, so we can change
362 its calling convention. We simply mark all static functions whose
363 address is not taken as local.
365 We also change the TREE_PUBLIC flag of all declarations that are public
366 in language point of view but we want to overwrite this default
367 via visibilities for the backend point of view. */
370 function_and_variable_visibility (bool whole_program
)
372 struct cgraph_node
*node
;
373 struct varpool_node
*vnode
;
375 for (node
= cgraph_nodes
; node
; node
= node
->next
)
377 /* C++ FE on lack of COMDAT support create local COMDAT functions
378 (that ought to be shared but can not due to object format
379 limitations). It is neccesary to keep the flag to make rest of C++ FE
380 happy. Clear the flag here to avoid confusion in middle-end. */
381 if (DECL_COMDAT (node
->decl
) && !TREE_PUBLIC (node
->decl
))
382 DECL_COMDAT (node
->decl
) = 0;
383 /* For external decls stop tracking same_comdat_group, it doesn't matter
384 what comdat group they are in when they won't be emitted in this TU,
385 and simplifies later passes. */
386 if (node
->same_comdat_group
&& DECL_EXTERNAL (node
->decl
))
388 struct cgraph_node
*n
= node
, *next
;
391 /* If at least one of same comdat group functions is external,
392 all of them have to be, otherwise it is a front-end bug. */
393 gcc_assert (DECL_EXTERNAL (n
->decl
));
394 next
= n
->same_comdat_group
;
395 n
->same_comdat_group
= NULL
;
400 gcc_assert ((!DECL_WEAK (node
->decl
) && !DECL_COMDAT (node
->decl
))
401 || TREE_PUBLIC (node
->decl
) || DECL_EXTERNAL (node
->decl
));
402 if (cgraph_externally_visible_p (node
, whole_program
))
404 gcc_assert (!node
->global
.inlined_to
);
405 node
->local
.externally_visible
= true;
408 node
->local
.externally_visible
= false;
409 if (!node
->local
.externally_visible
&& node
->analyzed
410 && !DECL_EXTERNAL (node
->decl
))
412 gcc_assert (whole_program
|| !TREE_PUBLIC (node
->decl
));
413 cgraph_make_decl_local (node
->decl
);
415 node
->local
.local
= (cgraph_only_called_directly_p (node
)
417 && !DECL_EXTERNAL (node
->decl
)
418 && !node
->local
.externally_visible
);
420 for (vnode
= varpool_nodes
; vnode
; vnode
= vnode
->next
)
422 /* weak flag makes no sense on local variables. */
423 gcc_assert (!DECL_WEAK (vnode
->decl
)
424 || TREE_PUBLIC (vnode
->decl
) || DECL_EXTERNAL (vnode
->decl
));
425 /* In several cases declarations can not be common:
427 - when declaration has initializer
429 - when it has specific section
430 - when it resides in non-generic address space.
431 - if declaration is local, it will get into .local common section
432 so common flag is not needed. Frontends still produce these in
433 certain cases, such as for:
435 static int a __attribute__ ((common))
437 Canonicalize things here and clear the redundant flag. */
438 if (DECL_COMMON (vnode
->decl
)
439 && (!(TREE_PUBLIC (vnode
->decl
) || DECL_EXTERNAL (vnode
->decl
))
440 || (DECL_INITIAL (vnode
->decl
)
441 && DECL_INITIAL (vnode
->decl
) != error_mark_node
)
442 || DECL_WEAK (vnode
->decl
)
443 || DECL_SECTION_NAME (vnode
->decl
) != NULL
444 || ! (ADDR_SPACE_GENERIC_P
445 (TYPE_ADDR_SPACE (TREE_TYPE (vnode
->decl
))))))
446 DECL_COMMON (vnode
->decl
) = 0;
448 for (vnode
= varpool_nodes_queue
; vnode
; vnode
= vnode
->next_needed
)
450 if (!vnode
->finalized
)
453 && (DECL_COMDAT (vnode
->decl
) || TREE_PUBLIC (vnode
->decl
))
455 /* We can privatize comdat readonly variables whose address is not taken,
456 but doing so is not going to bring us optimization oppurtunities until
457 we start reordering datastructures. */
458 || DECL_COMDAT (vnode
->decl
)
459 || DECL_WEAK (vnode
->decl
)
460 || lookup_attribute ("externally_visible",
461 DECL_ATTRIBUTES (vnode
->decl
))))
462 vnode
->externally_visible
= true;
464 vnode
->externally_visible
= false;
465 if (!vnode
->externally_visible
)
467 gcc_assert (whole_program
|| !TREE_PUBLIC (vnode
->decl
));
468 cgraph_make_decl_local (vnode
->decl
);
470 gcc_assert (TREE_STATIC (vnode
->decl
));
475 fprintf (dump_file
, "\nMarking local functions:");
476 for (node
= cgraph_nodes
; node
; node
= node
->next
)
477 if (node
->local
.local
)
478 fprintf (dump_file
, " %s", cgraph_node_name (node
));
479 fprintf (dump_file
, "\n\n");
480 fprintf (dump_file
, "\nMarking externally visible functions:");
481 for (node
= cgraph_nodes
; node
; node
= node
->next
)
482 if (node
->local
.externally_visible
)
483 fprintf (dump_file
, " %s", cgraph_node_name (node
));
484 fprintf (dump_file
, "\n\n");
485 fprintf (dump_file
, "\nMarking externally visible variables:");
486 for (vnode
= varpool_nodes_queue
; vnode
; vnode
= vnode
->next_needed
)
487 if (vnode
->externally_visible
)
488 fprintf (dump_file
, " %s", varpool_node_name (vnode
));
489 fprintf (dump_file
, "\n\n");
491 cgraph_function_flags_ready
= true;
495 /* Local function pass handling visibilities. This happens before LTO streaming
496 so in particular -fwhole-program should be ignored at this level. */
499 local_function_and_variable_visibility (void)
501 return function_and_variable_visibility (flag_whole_program
&& !flag_lto
&& !flag_whopr
);
504 struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility
=
508 "visibility", /* name */
510 local_function_and_variable_visibility
,/* execute */
513 0, /* static_pass_number */
514 TV_CGRAPHOPT
, /* tv_id */
515 0, /* properties_required */
516 0, /* properties_provided */
517 0, /* properties_destroyed */
518 0, /* todo_flags_start */
519 TODO_remove_functions
| TODO_dump_cgraph
/* todo_flags_finish */
523 /* Do not re-run on ltrans stage. */
526 gate_whole_program_function_and_variable_visibility (void)
531 /* Bring functionss local at LTO time whith -fwhole-program. */
534 whole_program_function_and_variable_visibility (void)
536 struct cgraph_node
*node
;
537 struct varpool_node
*vnode
;
539 function_and_variable_visibility (flag_whole_program
);
541 for (node
= cgraph_nodes
; node
; node
= node
->next
)
542 if ((node
->local
.externally_visible
&& !DECL_COMDAT (node
->decl
))
543 && node
->local
.finalized
)
544 cgraph_mark_needed_node (node
);
545 for (vnode
= varpool_nodes_queue
; vnode
; vnode
= vnode
->next_needed
)
546 if (vnode
->externally_visible
&& !DECL_COMDAT (vnode
->decl
))
547 varpool_mark_needed_node (vnode
);
550 fprintf (dump_file
, "\nNeeded variables:");
551 for (vnode
= varpool_nodes_queue
; vnode
; vnode
= vnode
->next_needed
)
553 fprintf (dump_file
, " %s", varpool_node_name (vnode
));
554 fprintf (dump_file
, "\n\n");
559 struct ipa_opt_pass_d pass_ipa_whole_program_visibility
=
563 "whole-program", /* name */
564 gate_whole_program_function_and_variable_visibility
,/* gate */
565 whole_program_function_and_variable_visibility
,/* execute */
568 0, /* static_pass_number */
569 TV_CGRAPHOPT
, /* tv_id */
570 0, /* properties_required */
571 0, /* properties_provided */
572 0, /* properties_destroyed */
573 0, /* todo_flags_start */
574 TODO_dump_cgraph
| TODO_remove_functions
/* todo_flags_finish */
576 NULL
, /* generate_summary */
577 NULL
, /* write_summary */
578 NULL
, /* read_summary */
579 NULL
, /* write_optimization_summary */
580 NULL
, /* read_optimization_summary */
581 NULL
, /* stmt_fixup */
583 NULL
, /* function_transform */
584 NULL
, /* variable_transform */
587 /* Hash a cgraph node set element. */
590 hash_cgraph_node_set_element (const void *p
)
592 const_cgraph_node_set_element element
= (const_cgraph_node_set_element
) p
;
593 return htab_hash_pointer (element
->node
);
596 /* Compare two cgraph node set elements. */
599 eq_cgraph_node_set_element (const void *p1
, const void *p2
)
601 const_cgraph_node_set_element e1
= (const_cgraph_node_set_element
) p1
;
602 const_cgraph_node_set_element e2
= (const_cgraph_node_set_element
) p2
;
604 return e1
->node
== e2
->node
;
607 /* Create a new cgraph node set. */
610 cgraph_node_set_new (void)
612 cgraph_node_set new_node_set
;
614 new_node_set
= GGC_NEW (struct cgraph_node_set_def
);
615 new_node_set
->hashtab
= htab_create_ggc (10,
616 hash_cgraph_node_set_element
,
617 eq_cgraph_node_set_element
,
619 new_node_set
->nodes
= NULL
;
623 /* Add cgraph_node NODE to cgraph_node_set SET. */
626 cgraph_node_set_add (cgraph_node_set set
, struct cgraph_node
*node
)
629 cgraph_node_set_element element
;
630 struct cgraph_node_set_element_def dummy
;
633 slot
= htab_find_slot (set
->hashtab
, &dummy
, INSERT
);
635 if (*slot
!= HTAB_EMPTY_ENTRY
)
637 element
= (cgraph_node_set_element
) *slot
;
638 gcc_assert (node
== element
->node
639 && (VEC_index (cgraph_node_ptr
, set
->nodes
, element
->index
)
644 /* Insert node into hash table. */
646 (cgraph_node_set_element
) GGC_NEW (struct cgraph_node_set_element_def
);
647 element
->node
= node
;
648 element
->index
= VEC_length (cgraph_node_ptr
, set
->nodes
);
651 /* Insert into node vector. */
652 VEC_safe_push (cgraph_node_ptr
, gc
, set
->nodes
, node
);
655 /* Remove cgraph_node NODE from cgraph_node_set SET. */
658 cgraph_node_set_remove (cgraph_node_set set
, struct cgraph_node
*node
)
660 void **slot
, **last_slot
;
661 cgraph_node_set_element element
, last_element
;
662 struct cgraph_node
*last_node
;
663 struct cgraph_node_set_element_def dummy
;
666 slot
= htab_find_slot (set
->hashtab
, &dummy
, NO_INSERT
);
670 element
= (cgraph_node_set_element
) *slot
;
671 gcc_assert (VEC_index (cgraph_node_ptr
, set
->nodes
, element
->index
)
674 /* Remove from vector. We do this by swapping node with the last element
676 last_node
= VEC_pop (cgraph_node_ptr
, set
->nodes
);
677 if (last_node
!= node
)
679 dummy
.node
= last_node
;
680 last_slot
= htab_find_slot (set
->hashtab
, &dummy
, NO_INSERT
);
681 last_element
= (cgraph_node_set_element
) *last_slot
;
682 gcc_assert (last_element
);
684 /* Move the last element to the original spot of NODE. */
685 last_element
->index
= element
->index
;
686 VEC_replace (cgraph_node_ptr
, set
->nodes
, last_element
->index
,
690 /* Remove element from hash table. */
691 htab_clear_slot (set
->hashtab
, slot
);
695 /* Find NODE in SET and return an iterator to it if found. A null iterator
696 is returned if NODE is not in SET. */
698 cgraph_node_set_iterator
699 cgraph_node_set_find (cgraph_node_set set
, struct cgraph_node
*node
)
702 struct cgraph_node_set_element_def dummy
;
703 cgraph_node_set_element element
;
704 cgraph_node_set_iterator csi
;
707 slot
= htab_find_slot (set
->hashtab
, &dummy
, NO_INSERT
);
709 csi
.index
= (unsigned) ~0;
712 element
= (cgraph_node_set_element
) *slot
;
713 gcc_assert (VEC_index (cgraph_node_ptr
, set
->nodes
, element
->index
)
715 csi
.index
= element
->index
;
722 /* Dump content of SET to file F. */
725 dump_cgraph_node_set (FILE *f
, cgraph_node_set set
)
727 cgraph_node_set_iterator iter
;
729 for (iter
= csi_start (set
); !csi_end_p (iter
); csi_next (&iter
))
731 struct cgraph_node
*node
= csi_node (iter
);
732 dump_cgraph_node (f
, node
);
736 /* Dump content of SET to stderr. */
739 debug_cgraph_node_set (cgraph_node_set set
)
741 dump_cgraph_node_set (stderr
, set
);