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) && !DECL_COMDAT (vnode->decl))
322 || TREE_PUBLIC (vnode->decl) || DECL_EXTERNAL (node->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;
341 gcc_assert (TREE_STATIC (vnode->decl));
346 fprintf (dump_file, "\nMarking local functions:");
347 for (node = cgraph_nodes; node; node = node->next)
348 if (node->local.local)
349 fprintf (dump_file, " %s", cgraph_node_name (node));
350 fprintf (dump_file, "\n\n");
351 fprintf (dump_file, "\nMarking externally visible functions:");
352 for (node = cgraph_nodes; node; node = node->next)
353 if (node->local.externally_visible)
354 fprintf (dump_file, " %s", cgraph_node_name (node));
355 fprintf (dump_file, "\n\n");
356 fprintf (dump_file, "\nMarking externally visible variables:");
357 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
358 if (vnode->externally_visible)
359 fprintf (dump_file, " %s", varpool_node_name (vnode));
360 fprintf (dump_file, "\n\n");
362 cgraph_function_flags_ready = true;
366 /* Local function pass handling visibilities. This happens before LTO streaming
367 so in particular -fwhole-program should be ignored at this level. */
370 local_function_and_variable_visibility (void)
372 return function_and_variable_visibility (flag_whole_program && !flag_lto && !flag_whopr);
375 struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility =
379 "visibility", /* name */
381 local_function_and_variable_visibility,/* execute */
384 0, /* static_pass_number */
385 TV_CGRAPHOPT, /* tv_id */
386 0, /* properties_required */
387 0, /* properties_provided */
388 0, /* properties_destroyed */
389 0, /* todo_flags_start */
390 TODO_remove_functions | TODO_dump_cgraph/* todo_flags_finish */
394 /* Do not re-run on ltrans stage. */
397 gate_whole_program_function_and_variable_visibility (void)
402 /* Bring functionss local at LTO time whith -fwhole-program. */
405 whole_program_function_and_variable_visibility (void)
407 struct cgraph_node *node;
408 struct varpool_node *vnode;
410 function_and_variable_visibility (flag_whole_program);
412 for (node = cgraph_nodes; node; node = node->next)
413 if ((node->local.externally_visible && !DECL_COMDAT (node->decl))
414 && node->local.finalized)
415 cgraph_mark_needed_node (node);
416 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
417 if (vnode->externally_visible && !DECL_COMDAT (vnode->decl))
418 varpool_mark_needed_node (vnode);
421 fprintf (dump_file, "\nNeeded variables:");
422 for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed)
424 fprintf (dump_file, " %s", varpool_node_name (vnode));
425 fprintf (dump_file, "\n\n");
430 struct ipa_opt_pass_d pass_ipa_whole_program_visibility =
434 "whole-program", /* name */
435 gate_whole_program_function_and_variable_visibility,/* gate */
436 whole_program_function_and_variable_visibility,/* execute */
439 0, /* static_pass_number */
440 TV_CGRAPHOPT, /* tv_id */
441 0, /* properties_required */
442 0, /* properties_provided */
443 0, /* properties_destroyed */
444 0, /* todo_flags_start */
445 TODO_dump_cgraph | TODO_remove_functions/* todo_flags_finish */
447 NULL, /* generate_summary */
448 NULL, /* write_summary */
449 NULL, /* read_summary */
450 NULL, /* function_read_summary */
451 NULL, /* stmt_fixup */
453 NULL, /* function_transform */
454 NULL, /* variable_transform */
457 /* Hash a cgraph node set element. */
460 hash_cgraph_node_set_element (const void *p)
462 const_cgraph_node_set_element element = (const_cgraph_node_set_element) p;
463 return htab_hash_pointer (element->node);
466 /* Compare two cgraph node set elements. */
469 eq_cgraph_node_set_element (const void *p1, const void *p2)
471 const_cgraph_node_set_element e1 = (const_cgraph_node_set_element) p1;
472 const_cgraph_node_set_element e2 = (const_cgraph_node_set_element) p2;
474 return e1->node == e2->node;
477 /* Create a new cgraph node set. */
480 cgraph_node_set_new (void)
482 cgraph_node_set new_node_set;
484 new_node_set = GGC_NEW (struct cgraph_node_set_def);
485 new_node_set->hashtab = htab_create_ggc (10,
486 hash_cgraph_node_set_element,
487 eq_cgraph_node_set_element,
489 new_node_set->nodes = NULL;
493 /* Add cgraph_node NODE to cgraph_node_set SET. */
496 cgraph_node_set_add (cgraph_node_set set, struct cgraph_node *node)
499 cgraph_node_set_element element;
500 struct cgraph_node_set_element_def dummy;
503 slot = htab_find_slot (set->hashtab, &dummy, INSERT);
505 if (*slot != HTAB_EMPTY_ENTRY)
507 element = (cgraph_node_set_element) *slot;
508 gcc_assert (node == element->node
509 && (VEC_index (cgraph_node_ptr, set->nodes, element->index)
514 /* Insert node into hash table. */
516 (cgraph_node_set_element) GGC_NEW (struct cgraph_node_set_element_def);
517 element->node = node;
518 element->index = VEC_length (cgraph_node_ptr, set->nodes);
521 /* Insert into node vector. */
522 VEC_safe_push (cgraph_node_ptr, gc, set->nodes, node);
525 /* Remove cgraph_node NODE from cgraph_node_set SET. */
528 cgraph_node_set_remove (cgraph_node_set set, struct cgraph_node *node)
530 void **slot, **last_slot;
531 cgraph_node_set_element element, last_element;
532 struct cgraph_node *last_node;
533 struct cgraph_node_set_element_def dummy;
536 slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
540 element = (cgraph_node_set_element) *slot;
541 gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index)
544 /* Remove from vector. We do this by swapping node with the last element
546 last_node = VEC_pop (cgraph_node_ptr, set->nodes);
547 if (last_node != node)
549 dummy.node = last_node;
550 last_slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
551 last_element = (cgraph_node_set_element) *last_slot;
552 gcc_assert (last_element);
554 /* Move the last element to the original spot of NODE. */
555 last_element->index = element->index;
556 VEC_replace (cgraph_node_ptr, set->nodes, last_element->index,
560 /* Remove element from hash table. */
561 htab_clear_slot (set->hashtab, slot);
565 /* Find NODE in SET and return an iterator to it if found. A null iterator
566 is returned if NODE is not in SET. */
568 cgraph_node_set_iterator
569 cgraph_node_set_find (cgraph_node_set set, struct cgraph_node *node)
572 struct cgraph_node_set_element_def dummy;
573 cgraph_node_set_element element;
574 cgraph_node_set_iterator csi;
577 slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT);
579 csi.index = (unsigned) ~0;
582 element = (cgraph_node_set_element) *slot;
583 gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index)
585 csi.index = element->index;
592 /* Dump content of SET to file F. */
595 dump_cgraph_node_set (FILE *f, cgraph_node_set set)
597 cgraph_node_set_iterator iter;
599 for (iter = csi_start (set); !csi_end_p (iter); csi_next (&iter))
601 struct cgraph_node *node = csi_node (iter);
602 dump_cgraph_node (f, node);
606 /* Dump content of SET to stderr. */
609 debug_cgraph_node_set (cgraph_node_set set)
611 dump_cgraph_node_set (stderr, set);