1 /* Basic IPA optimizations and utilities.
2 Copyright (C) 2003, 2004, 2005, 2007, 2008 Free Software Foundation,
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 if (!edge->caller->aux)
75 if (!edge->caller->callers)
76 edge->caller->aux = &last;
78 edge->caller->aux = edge->caller->callers;
79 stack[stack_size++] = node2;
84 if (node2->aux == &last)
86 order[order_pos++] = node2;
88 node2 = stack[--stack_size];
95 for (node = cgraph_nodes; node; node = node->next)
100 /* Look for all functions inlined to NODE and update their inlined_to pointers
104 update_inlined_to_pointer (struct cgraph_node *node, struct cgraph_node *inlined_to)
106 struct cgraph_edge *e;
107 for (e = node->callees; e; e = e->next_callee)
108 if (e->callee->global.inlined_to)
110 e->callee->global.inlined_to = inlined_to;
111 update_inlined_to_pointer (e->callee, inlined_to);
115 /* Perform reachability analysis and reclaim all unreachable nodes.
116 If BEFORE_INLINING_P is true this function is called before inlining
117 decisions has been made. If BEFORE_INLINING_P is false this function also
118 removes unneeded bodies of extern inline functions. */
121 cgraph_remove_unreachable_nodes (bool before_inlining_p, FILE *file)
123 struct cgraph_node *first = (struct cgraph_node *) (void *) 1;
124 struct cgraph_node *node, *next;
125 bool changed = false;
127 #ifdef ENABLE_CHECKING
131 fprintf (file, "\nReclaiming functions:");
132 #ifdef ENABLE_CHECKING
133 for (node = cgraph_nodes; node; node = node->next)
134 gcc_assert (!node->aux);
136 for (node = cgraph_nodes; node; node = node->next)
137 if (!cgraph_can_remove_if_no_direct_calls_p (node)
138 && ((!DECL_EXTERNAL (node->decl))
140 || before_inlining_p))
142 gcc_assert (!node->global.inlined_to);
147 gcc_assert (!node->aux);
149 /* Perform reachability analysis. As a special case do not consider
150 extern inline functions not inlined as live because we won't output
152 while (first != (void *) 1)
154 struct cgraph_edge *e;
156 first = (struct cgraph_node *) first->aux;
158 for (e = node->callees; e; e = e->next_callee)
161 && (!e->inline_failed || !e->callee->analyzed
162 || (!DECL_EXTERNAL (e->callee->decl))
163 || before_inlining_p))
165 e->callee->aux = first;
168 while (node->clone_of && !node->clone_of->aux && !gimple_has_body_p (node->decl))
170 node = node->clone_of;
176 /* Remove unreachable nodes. Extern inline functions need special care;
177 Unreachable extern inline functions shall be removed.
178 Reachable extern inline functions we never inlined shall get their bodies
180 Reachable extern inline functions we sometimes inlined will be turned into
181 unanalyzed nodes so they look like for true extern functions to the rest
182 of code. Body of such functions is released via remove_node once the
183 inline clones are eliminated. */
184 for (node = cgraph_nodes; node; node = next)
189 node->global.inlined_to = NULL;
191 fprintf (file, " %s", cgraph_node_name (node));
192 if (!node->analyzed || !DECL_EXTERNAL (node->decl)
193 || before_inlining_p)
194 cgraph_remove_node (node);
197 struct cgraph_edge *e;
199 /* See if there is reachable caller. */
200 for (e = node->callers; e; e = e->next_caller)
204 /* If so, we need to keep node in the callgraph. */
205 if (e || node->needed)
207 struct cgraph_node *clone;
209 /* If there are still clones, we must keep body around.
210 Otherwise we can just remove the body but keep the clone. */
211 for (clone = node->clones; clone;
212 clone = clone->next_sibling_clone)
217 cgraph_release_function_body (node);
218 cgraph_node_remove_callees (node);
219 node->analyzed = false;
220 node->local.inlinable = false;
224 cgraph_remove_node (node);
229 for (node = cgraph_nodes; node; node = node->next)
231 /* Inline clones might be kept around so their materializing allows further
232 cloning. If the function the clone is inlined into is removed, we need
233 to turn it into normal cone. */
234 if (node->global.inlined_to
237 gcc_assert (node->clones);
238 node->global.inlined_to = NULL;
239 update_inlined_to_pointer (node, node);
243 #ifdef ENABLE_CHECKING
247 /* Reclaim alias pairs for functions that have disappeared from the
249 remove_unreachable_alias_pairs ();
255 cgraph_externally_visible_p (struct cgraph_node *node, bool whole_program)
257 if (!node->local.finalized)
259 if (!DECL_COMDAT (node->decl)
260 && (!TREE_PUBLIC (node->decl) || DECL_EXTERNAL (node->decl)))
264 /* COMDAT functions must be shared only if they have address taken,
265 otherwise we can produce our own private implementation with
267 if (DECL_COMDAT (node->decl) && (node->address_taken || !node->analyzed))
269 if (MAIN_NAME_P (DECL_NAME (node->decl)))
271 if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (node->decl)))
276 /* Mark visibility of all functions.
278 A local function is one whose calls can occur only in the current
279 compilation unit and all its calls are explicit, so we can change
280 its calling convention. We simply mark all static functions whose
281 address is not taken as local.
283 We also change the TREE_PUBLIC flag of all declarations that are public
284 in language point of view but we want to overwrite this default
285 via visibilities for the backend point of view. */
288 function_and_variable_visibility (bool whole_program)
290 struct cgraph_node *node;
291 struct varpool_node *vnode;
293 for (node = cgraph_nodes; node; node = node->next)
295 gcc_assert ((!DECL_WEAK (node->decl) && !DECL_COMDAT (node->decl))
296 || TREE_PUBLIC (node->decl) || DECL_EXTERNAL (node->decl));
297 if (cgraph_externally_visible_p (node, whole_program))
299 gcc_assert (!node->global.inlined_to);
300 node->local.externally_visible = true;
303 node->local.externally_visible = false;
304 if (!node->local.externally_visible && node->analyzed
305 && !DECL_EXTERNAL (node->decl))
307 gcc_assert (whole_program || !TREE_PUBLIC (node->decl));
308 TREE_PUBLIC (node->decl) = 0;
309 DECL_COMDAT (node->decl) = 0;
310 DECL_WEAK (node->decl) = 0;
312 node->local.local = (cgraph_only_called_directly_p (node)
314 && !DECL_EXTERNAL (node->decl)
315 && !node->local.externally_visible);
317 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
319 if (!vnode->finalized)
321 gcc_assert ((!DECL_WEAK (vnode->decl) && !DECL_COMMON (vnode->decl))
322 || TREE_PUBLIC (vnode->decl) || DECL_EXTERNAL (vnode->decl));
324 && (DECL_COMDAT (vnode->decl) || TREE_PUBLIC (vnode->decl))
326 /* We can privatize comdat readonly variables whose address is not taken,
327 but doing so is not going to bring us optimization oppurtunities until
328 we start reordering datastructures. */
329 || DECL_COMDAT (vnode->decl)
330 || DECL_WEAK (vnode->decl)
331 || lookup_attribute ("externally_visible",
332 DECL_ATTRIBUTES (vnode->decl))))
333 vnode->externally_visible = true;
335 vnode->externally_visible = false;
336 if (!vnode->externally_visible)
338 gcc_assert (whole_program || !TREE_PUBLIC (vnode->decl));
339 TREE_PUBLIC (vnode->decl) = 0;
340 DECL_COMMON (vnode->decl) = 0;
342 gcc_assert (TREE_STATIC (vnode->decl));
347 fprintf (dump_file, "\nMarking local functions:");
348 for (node = cgraph_nodes; node; node = node->next)
349 if (node->local.local)
350 fprintf (dump_file, " %s", cgraph_node_name (node));
351 fprintf (dump_file, "\n\n");
352 fprintf (dump_file, "\nMarking externally visible functions:");
353 for (node = cgraph_nodes; node; node = node->next)
354 if (node->local.externally_visible)
355 fprintf (dump_file, " %s", cgraph_node_name (node));
356 fprintf (dump_file, "\n\n");
357 fprintf (dump_file, "\nMarking externally visible variables:");
358 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
359 if (vnode->externally_visible)
360 fprintf (dump_file, " %s", varpool_node_name (vnode));
361 fprintf (dump_file, "\n\n");
363 cgraph_function_flags_ready = true;
367 /* Local function pass handling visibilities. This happens before LTO streaming
368 so in particular -fwhole-program should be ignored at this level. */
371 local_function_and_variable_visibility (void)
373 return function_and_variable_visibility (flag_whole_program && !flag_lto && !flag_whopr);
376 struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility =
380 "visibility", /* name */
382 local_function_and_variable_visibility,/* execute */
385 0, /* static_pass_number */
386 TV_CGRAPHOPT, /* tv_id */
387 0, /* properties_required */
388 0, /* properties_provided */
389 0, /* properties_destroyed */
390 0, /* todo_flags_start */
391 TODO_remove_functions | TODO_dump_cgraph/* todo_flags_finish */
395 /* Do not re-run on ltrans stage. */
398 gate_whole_program_function_and_variable_visibility (void)
403 /* Bring functionss local at LTO time whith -fwhole-program. */
406 whole_program_function_and_variable_visibility (void)
408 struct cgraph_node *node;
409 struct varpool_node *vnode;
411 function_and_variable_visibility (flag_whole_program);
413 for (node = cgraph_nodes; node; node = node->next)
414 if ((node->local.externally_visible && !DECL_COMDAT (node->decl))
415 && node->local.finalized)
416 cgraph_mark_needed_node (node);
417 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
418 if (vnode->externally_visible && !DECL_COMDAT (vnode->decl))
419 varpool_mark_needed_node (vnode);
422 fprintf (dump_file, "\nNeeded variables:");
423 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
425 fprintf (dump_file, " %s", varpool_node_name (vnode));
426 fprintf (dump_file, "\n\n");
431 struct ipa_opt_pass_d pass_ipa_whole_program_visibility =
435 "whole-program", /* name */
436 gate_whole_program_function_and_variable_visibility,/* gate */
437 whole_program_function_and_variable_visibility,/* execute */
440 0, /* static_pass_number */
441 TV_CGRAPHOPT, /* tv_id */
442 0, /* properties_required */
443 0, /* properties_provided */
444 0, /* properties_destroyed */
445 0, /* todo_flags_start */
446 TODO_dump_cgraph | TODO_remove_functions/* todo_flags_finish */
448 NULL, /* generate_summary */
449 NULL, /* write_summary */
450 NULL, /* read_summary */
451 NULL, /* function_read_summary */
452 NULL, /* stmt_fixup */
454 NULL, /* function_transform */
455 NULL, /* variable_transform */
458 /* Hash a cgraph node set element. */
461 hash_cgraph_node_set_element (const void *p)
463 const_cgraph_node_set_element element = (const_cgraph_node_set_element) p;
464 return htab_hash_pointer (element->node);
467 /* Compare two cgraph node set elements. */
470 eq_cgraph_node_set_element (const void *p1, const void *p2)
472 const_cgraph_node_set_element e1 = (const_cgraph_node_set_element) p1;
473 const_cgraph_node_set_element e2 = (const_cgraph_node_set_element) p2;
475 return e1->node == e2->node;
478 /* Create a new cgraph node set. */
481 cgraph_node_set_new (void)
483 cgraph_node_set new_node_set;
485 new_node_set = GGC_NEW (struct cgraph_node_set_def);
486 new_node_set->hashtab = htab_create_ggc (10,
487 hash_cgraph_node_set_element,
488 eq_cgraph_node_set_element,
490 new_node_set->nodes = NULL;
494 /* Add cgraph_node NODE to cgraph_node_set SET. */
497 cgraph_node_set_add (cgraph_node_set set, struct cgraph_node *node)
500 cgraph_node_set_element element;
501 struct cgraph_node_set_element_def dummy;
504 slot = htab_find_slot (set->hashtab, &dummy, INSERT);
506 if (*slot != HTAB_EMPTY_ENTRY)
508 element = (cgraph_node_set_element) *slot;
509 gcc_assert (node == element->node
510 && (VEC_index (cgraph_node_ptr, set->nodes, element->index)
515 /* Insert node into hash table. */
517 (cgraph_node_set_element) GGC_NEW (struct cgraph_node_set_element_def);
518 element->node = node;
519 element->index = VEC_length (cgraph_node_ptr, set->nodes);
522 /* Insert into node vector. */
523 VEC_safe_push (cgraph_node_ptr, gc, set->nodes, node);
526 /* Remove cgraph_node NODE from cgraph_node_set SET. */
529 cgraph_node_set_remove (cgraph_node_set set, struct cgraph_node *node)
531 void **slot, **last_slot;
532 cgraph_node_set_element element, last_element;
533 struct cgraph_node *last_node;
534 struct cgraph_node_set_element_def dummy;
537 slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
541 element = (cgraph_node_set_element) *slot;
542 gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index)
545 /* Remove from vector. We do this by swapping node with the last element
547 last_node = VEC_pop (cgraph_node_ptr, set->nodes);
548 if (last_node != node)
550 dummy.node = last_node;
551 last_slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
552 last_element = (cgraph_node_set_element) *last_slot;
553 gcc_assert (last_element);
555 /* Move the last element to the original spot of NODE. */
556 last_element->index = element->index;
557 VEC_replace (cgraph_node_ptr, set->nodes, last_element->index,
561 /* Remove element from hash table. */
562 htab_clear_slot (set->hashtab, slot);
566 /* Find NODE in SET and return an iterator to it if found. A null iterator
567 is returned if NODE is not in SET. */
569 cgraph_node_set_iterator
570 cgraph_node_set_find (cgraph_node_set set, struct cgraph_node *node)
573 struct cgraph_node_set_element_def dummy;
574 cgraph_node_set_element element;
575 cgraph_node_set_iterator csi;
578 slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
580 csi.index = (unsigned) ~0;
583 element = (cgraph_node_set_element) *slot;
584 gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index)
586 csi.index = element->index;
593 /* Dump content of SET to file F. */
596 dump_cgraph_node_set (FILE *f, cgraph_node_set set)
598 cgraph_node_set_iterator iter;
600 for (iter = csi_start (set); !csi_end_p (iter); csi_next (&iter))
602 struct cgraph_node *node = csi_node (iter);
603 dump_cgraph_node (f, node);
607 /* Dump content of SET to stderr. */
610 debug_cgraph_node_set (cgraph_node_set set)
612 dump_cgraph_node_set (stderr, set);