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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [ipa.c] - Rev 283
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/* Basic IPA optimizations and utilities. Copyright (C) 2003, 2004, 2005, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see <http://www.gnu.org/licenses/>. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "cgraph.h" #include "tree-pass.h" #include "timevar.h" #include "gimple.h" #include "ggc.h" /* Fill array order with all nodes with output flag set in the reverse topological order. */ int cgraph_postorder (struct cgraph_node **order) { struct cgraph_node *node, *node2; int stack_size = 0; int order_pos = 0; struct cgraph_edge *edge, last; int pass; struct cgraph_node **stack = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes); /* We have to deal with cycles nicely, so use a depth first traversal output algorithm. Ignore the fact that some functions won't need to be output and put them into order as well, so we get dependencies right through inline functions. */ for (node = cgraph_nodes; node; node = node->next) node->aux = NULL; for (pass = 0; pass < 2; pass++) for (node = cgraph_nodes; node; node = node->next) if (!node->aux && (pass || (!cgraph_only_called_directly_p (node) && !node->address_taken))) { node2 = node; if (!node->callers) node->aux = &last; else node->aux = node->callers; while (node2) { while (node2->aux != &last) { edge = (struct cgraph_edge *) node2->aux; if (edge->next_caller) node2->aux = edge->next_caller; else node2->aux = &last; if (!edge->caller->aux) { if (!edge->caller->callers) edge->caller->aux = &last; else edge->caller->aux = edge->caller->callers; stack[stack_size++] = node2; node2 = edge->caller; break; } } if (node2->aux == &last) { order[order_pos++] = node2; if (stack_size) node2 = stack[--stack_size]; else node2 = NULL; } } } free (stack); for (node = cgraph_nodes; node; node = node->next) node->aux = NULL; return order_pos; } /* Look for all functions inlined to NODE and update their inlined_to pointers to INLINED_TO. */ static void update_inlined_to_pointer (struct cgraph_node *node, struct cgraph_node *inlined_to) { struct cgraph_edge *e; for (e = node->callees; e; e = e->next_callee) if (e->callee->global.inlined_to) { e->callee->global.inlined_to = inlined_to; update_inlined_to_pointer (e->callee, inlined_to); } } /* Perform reachability analysis and reclaim all unreachable nodes. If BEFORE_INLINING_P is true this function is called before inlining decisions has been made. If BEFORE_INLINING_P is false this function also removes unneeded bodies of extern inline functions. */ bool cgraph_remove_unreachable_nodes (bool before_inlining_p, FILE *file) { struct cgraph_node *first = (struct cgraph_node *) (void *) 1; struct cgraph_node *processed = (struct cgraph_node *) (void *) 2; struct cgraph_node *node, *next; bool changed = false; #ifdef ENABLE_CHECKING verify_cgraph (); #endif if (file) fprintf (file, "\nReclaiming functions:"); #ifdef ENABLE_CHECKING for (node = cgraph_nodes; node; node = node->next) gcc_assert (!node->aux); #endif for (node = cgraph_nodes; node; node = node->next) if (!cgraph_can_remove_if_no_direct_calls_p (node) && ((!DECL_EXTERNAL (node->decl)) || !node->analyzed || before_inlining_p)) { gcc_assert (!node->global.inlined_to); node->aux = first; first = node; node->reachable = true; } else { gcc_assert (!node->aux); node->reachable = false; } /* Perform reachability analysis. As a special case do not consider extern inline functions not inlined as live because we won't output them at all. */ while (first != (void *) 1) { struct cgraph_edge *e; node = first; first = (struct cgraph_node *) first->aux; node->aux = processed; if (node->reachable) for (e = node->callees; e; e = e->next_callee) if (!e->callee->reachable && node->analyzed && (!e->inline_failed || !e->callee->analyzed || (!DECL_EXTERNAL (e->callee->decl)) || before_inlining_p)) { bool prev_reachable = e->callee->reachable; e->callee->reachable |= node->reachable; if (!e->callee->aux || (e->callee->aux == processed && prev_reachable != e->callee->reachable)) { e->callee->aux = first; first = e->callee; } } /* If any function in a comdat group is reachable, force all other functions in the same comdat group to be also reachable. */ if (node->same_comdat_group && node->reachable && !node->global.inlined_to) { for (next = node->same_comdat_group; next != node; next = next->same_comdat_group) if (!next->reachable) { next->aux = first; first = next; next->reachable = true; } } /* We can freely remove inline clones even if they are cloned, however if function is clone of real clone, we must keep it around in order to make materialize_clones produce function body with the changes applied. */ while (node->clone_of && !node->clone_of->aux && !gimple_has_body_p (node->decl)) { bool noninline = node->clone_of->decl != node->decl; node = node->clone_of; if (noninline) { node->aux = first; first = node; break; } } } /* Remove unreachable nodes. Extern inline functions need special care; Unreachable extern inline functions shall be removed. Reachable extern inline functions we never inlined shall get their bodies eliminated. Reachable extern inline functions we sometimes inlined will be turned into unanalyzed nodes so they look like for true extern functions to the rest of code. Body of such functions is released via remove_node once the inline clones are eliminated. */ for (node = cgraph_nodes; node; node = next) { next = node->next; if (node->aux && !node->reachable) { cgraph_node_remove_callees (node); node->analyzed = false; node->local.inlinable = false; } if (!node->aux) { node->global.inlined_to = NULL; if (file) fprintf (file, " %s", cgraph_node_name (node)); if (!node->analyzed || !DECL_EXTERNAL (node->decl) || before_inlining_p) cgraph_remove_node (node); else { struct cgraph_edge *e; /* See if there is reachable caller. */ for (e = node->callers; e; e = e->next_caller) if (e->caller->aux) break; /* If so, we need to keep node in the callgraph. */ if (e || node->needed) { struct cgraph_node *clone; /* If there are still clones, we must keep body around. Otherwise we can just remove the body but keep the clone. */ for (clone = node->clones; clone; clone = clone->next_sibling_clone) if (clone->aux) break; if (!clone) { cgraph_release_function_body (node); node->analyzed = false; node->local.inlinable = false; } cgraph_node_remove_callees (node); if (node->prev_sibling_clone) node->prev_sibling_clone->next_sibling_clone = node->next_sibling_clone; else if (node->clone_of) node->clone_of->clones = node->next_sibling_clone; if (node->next_sibling_clone) node->next_sibling_clone->prev_sibling_clone = node->prev_sibling_clone; node->clone_of = NULL; node->next_sibling_clone = NULL; node->prev_sibling_clone = NULL; } else cgraph_remove_node (node); } changed = true; } } for (node = cgraph_nodes; node; node = node->next) { /* Inline clones might be kept around so their materializing allows further cloning. If the function the clone is inlined into is removed, we need to turn it into normal cone. */ if (node->global.inlined_to && !node->callers) { gcc_assert (node->clones); node->global.inlined_to = NULL; update_inlined_to_pointer (node, node); } node->aux = NULL; } #ifdef ENABLE_CHECKING verify_cgraph (); #endif /* Reclaim alias pairs for functions that have disappeared from the call graph. */ remove_unreachable_alias_pairs (); return changed; } static bool cgraph_externally_visible_p (struct cgraph_node *node, bool whole_program) { if (!node->local.finalized) return false; if (!DECL_COMDAT (node->decl) && (!TREE_PUBLIC (node->decl) || DECL_EXTERNAL (node->decl))) return false; if (!whole_program) return true; if (DECL_PRESERVE_P (node->decl)) return true; /* COMDAT functions must be shared only if they have address taken, otherwise we can produce our own private implementation with -fwhole-program. */ if (DECL_COMDAT (node->decl)) { if (node->address_taken || !node->analyzed) return true; if (node->same_comdat_group) { struct cgraph_node *next; /* If more than one function is in the same COMDAT group, it must be shared even if just one function in the comdat group has address taken. */ for (next = node->same_comdat_group; next != node; next = next->same_comdat_group) if (next->address_taken || !next->analyzed) return true; } } if (MAIN_NAME_P (DECL_NAME (node->decl))) return true; if (lookup_attribute ("externally_visible", DECL_ATTRIBUTES (node->decl))) return true; return false; } /* Dissolve the same_comdat_group list in which NODE resides. */ static void dissolve_same_comdat_group_list (struct cgraph_node *node) { struct cgraph_node *n = node, *next; do { next = n->same_comdat_group; n->same_comdat_group = NULL; n = next; } while (n != node); } /* Mark visibility of all functions. A local function is one whose calls can occur only in the current compilation unit and all its calls are explicit, so we can change its calling convention. We simply mark all static functions whose address is not taken as local. We also change the TREE_PUBLIC flag of all declarations that are public in language point of view but we want to overwrite this default via visibilities for the backend point of view. */ static unsigned int function_and_variable_visibility (bool whole_program) { struct cgraph_node *node; struct varpool_node *vnode; for (node = cgraph_nodes; node; node = node->next) { /* C++ FE on lack of COMDAT support create local COMDAT functions (that ought to be shared but can not due to object format limitations). It is neccesary to keep the flag to make rest of C++ FE happy. Clear the flag here to avoid confusion in middle-end. */ if (DECL_COMDAT (node->decl) && !TREE_PUBLIC (node->decl)) DECL_COMDAT (node->decl) = 0; /* For external decls stop tracking same_comdat_group, it doesn't matter what comdat group they are in when they won't be emitted in this TU, and simplifies later passes. */ if (node->same_comdat_group && DECL_EXTERNAL (node->decl)) { #ifdef ENABLE_CHECKING struct cgraph_node *n; for (n = node->same_comdat_group; n != node; n = n->same_comdat_group) /* If at least one of same comdat group functions is external, all of them have to be, otherwise it is a front-end bug. */ gcc_assert (DECL_EXTERNAL (n->decl)); #endif dissolve_same_comdat_group_list (node); } gcc_assert ((!DECL_WEAK (node->decl) && !DECL_COMDAT (node->decl)) || TREE_PUBLIC (node->decl) || DECL_EXTERNAL (node->decl)); if (cgraph_externally_visible_p (node, whole_program)) { gcc_assert (!node->global.inlined_to); node->local.externally_visible = true; } else node->local.externally_visible = false; if (!node->local.externally_visible && node->analyzed && !DECL_EXTERNAL (node->decl)) { gcc_assert (whole_program || !TREE_PUBLIC (node->decl)); cgraph_make_decl_local (node->decl); if (node->same_comdat_group) /* cgraph_externally_visible_p has already checked all other nodes in the group and they will all be made local. We need to dissolve the group at once so that the predicate does not segfault though. */ dissolve_same_comdat_group_list (node); } node->local.local = (cgraph_only_called_directly_p (node) && node->analyzed && !DECL_EXTERNAL (node->decl) && !node->local.externally_visible); } for (vnode = varpool_nodes; vnode; vnode = vnode->next) { /* weak flag makes no sense on local variables. */ gcc_assert (!DECL_WEAK (vnode->decl) || TREE_PUBLIC (vnode->decl) || DECL_EXTERNAL (vnode->decl)); /* In several cases declarations can not be common: - when declaration has initializer - when it is in weak - when it has specific section - when it resides in non-generic address space. - if declaration is local, it will get into .local common section so common flag is not needed. Frontends still produce these in certain cases, such as for: static int a __attribute__ ((common)) Canonicalize things here and clear the redundant flag. */ if (DECL_COMMON (vnode->decl) && (!(TREE_PUBLIC (vnode->decl) || DECL_EXTERNAL (vnode->decl)) || (DECL_INITIAL (vnode->decl) && DECL_INITIAL (vnode->decl) != error_mark_node) || DECL_WEAK (vnode->decl) || DECL_SECTION_NAME (vnode->decl) != NULL || ! (ADDR_SPACE_GENERIC_P (TYPE_ADDR_SPACE (TREE_TYPE (vnode->decl)))))) DECL_COMMON (vnode->decl) = 0; } for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed) { if (!vnode->finalized) continue; if (vnode->needed && (DECL_COMDAT (vnode->decl) || TREE_PUBLIC (vnode->decl)) && (!whole_program /* We can privatize comdat readonly variables whose address is not taken, but doing so is not going to bring us optimization oppurtunities until we start reordering datastructures. */ || DECL_COMDAT (vnode->decl) || DECL_WEAK (vnode->decl) || lookup_attribute ("externally_visible", DECL_ATTRIBUTES (vnode->decl)))) vnode->externally_visible = true; else vnode->externally_visible = false; if (!vnode->externally_visible) { gcc_assert (whole_program || !TREE_PUBLIC (vnode->decl)); cgraph_make_decl_local (vnode->decl); } gcc_assert (TREE_STATIC (vnode->decl)); } if (dump_file) { fprintf (dump_file, "\nMarking local functions:"); for (node = cgraph_nodes; node; node = node->next) if (node->local.local) fprintf (dump_file, " %s", cgraph_node_name (node)); fprintf (dump_file, "\n\n"); fprintf (dump_file, "\nMarking externally visible functions:"); for (node = cgraph_nodes; node; node = node->next) if (node->local.externally_visible) fprintf (dump_file, " %s", cgraph_node_name (node)); fprintf (dump_file, "\n\n"); fprintf (dump_file, "\nMarking externally visible variables:"); for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed) if (vnode->externally_visible) fprintf (dump_file, " %s", varpool_node_name (vnode)); fprintf (dump_file, "\n\n"); } cgraph_function_flags_ready = true; return 0; } /* Local function pass handling visibilities. This happens before LTO streaming so in particular -fwhole-program should be ignored at this level. */ static unsigned int local_function_and_variable_visibility (void) { return function_and_variable_visibility (flag_whole_program && !flag_lto && !flag_whopr); } struct simple_ipa_opt_pass pass_ipa_function_and_variable_visibility = { { SIMPLE_IPA_PASS, "visibility", /* name */ NULL, /* gate */ local_function_and_variable_visibility,/* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_CGRAPHOPT, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_remove_functions | TODO_dump_cgraph/* todo_flags_finish */ } }; /* Do not re-run on ltrans stage. */ static bool gate_whole_program_function_and_variable_visibility (void) { return !flag_ltrans; } /* Bring functionss local at LTO time whith -fwhole-program. */ static unsigned int whole_program_function_and_variable_visibility (void) { struct cgraph_node *node; struct varpool_node *vnode; function_and_variable_visibility (flag_whole_program); for (node = cgraph_nodes; node; node = node->next) if ((node->local.externally_visible && !DECL_COMDAT (node->decl)) && node->local.finalized) cgraph_mark_needed_node (node); for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed) if (vnode->externally_visible && !DECL_COMDAT (vnode->decl)) varpool_mark_needed_node (vnode); if (dump_file) { fprintf (dump_file, "\nNeeded variables:"); for (vnode = varpool_nodes_queue; vnode; vnode = vnode->next_needed) if (vnode->needed) fprintf (dump_file, " %s", varpool_node_name (vnode)); fprintf (dump_file, "\n\n"); } return 0; } struct ipa_opt_pass_d pass_ipa_whole_program_visibility = { { IPA_PASS, "whole-program", /* name */ gate_whole_program_function_and_variable_visibility,/* gate */ whole_program_function_and_variable_visibility,/* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_CGRAPHOPT, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_dump_cgraph | TODO_remove_functions/* todo_flags_finish */ }, NULL, /* generate_summary */ NULL, /* write_summary */ NULL, /* read_summary */ NULL, /* function_read_summary */ NULL, /* stmt_fixup */ 0, /* TODOs */ NULL, /* function_transform */ NULL, /* variable_transform */ }; /* Hash a cgraph node set element. */ static hashval_t hash_cgraph_node_set_element (const void *p) { const_cgraph_node_set_element element = (const_cgraph_node_set_element) p; return htab_hash_pointer (element->node); } /* Compare two cgraph node set elements. */ static int eq_cgraph_node_set_element (const void *p1, const void *p2) { const_cgraph_node_set_element e1 = (const_cgraph_node_set_element) p1; const_cgraph_node_set_element e2 = (const_cgraph_node_set_element) p2; return e1->node == e2->node; } /* Create a new cgraph node set. */ cgraph_node_set cgraph_node_set_new (void) { cgraph_node_set new_node_set; new_node_set = GGC_NEW (struct cgraph_node_set_def); new_node_set->hashtab = htab_create_ggc (10, hash_cgraph_node_set_element, eq_cgraph_node_set_element, NULL); new_node_set->nodes = NULL; return new_node_set; } /* Add cgraph_node NODE to cgraph_node_set SET. */ void cgraph_node_set_add (cgraph_node_set set, struct cgraph_node *node) { void **slot; cgraph_node_set_element element; struct cgraph_node_set_element_def dummy; dummy.node = node; slot = htab_find_slot (set->hashtab, &dummy, INSERT); if (*slot != HTAB_EMPTY_ENTRY) { element = (cgraph_node_set_element) *slot; gcc_assert (node == element->node && (VEC_index (cgraph_node_ptr, set->nodes, element->index) == node)); return; } /* Insert node into hash table. */ element = (cgraph_node_set_element) GGC_NEW (struct cgraph_node_set_element_def); element->node = node; element->index = VEC_length (cgraph_node_ptr, set->nodes); *slot = element; /* Insert into node vector. */ VEC_safe_push (cgraph_node_ptr, gc, set->nodes, node); } /* Remove cgraph_node NODE from cgraph_node_set SET. */ void cgraph_node_set_remove (cgraph_node_set set, struct cgraph_node *node) { void **slot, **last_slot; cgraph_node_set_element element, last_element; struct cgraph_node *last_node; struct cgraph_node_set_element_def dummy; dummy.node = node; slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT); if (slot == NULL) return; element = (cgraph_node_set_element) *slot; gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index) == node); /* Remove from vector. We do this by swapping node with the last element of the vector. */ last_node = VEC_pop (cgraph_node_ptr, set->nodes); if (last_node != node) { dummy.node = last_node; last_slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT); last_element = (cgraph_node_set_element) *last_slot; gcc_assert (last_element); /* Move the last element to the original spot of NODE. */ last_element->index = element->index; VEC_replace (cgraph_node_ptr, set->nodes, last_element->index, last_node); } /* Remove element from hash table. */ htab_clear_slot (set->hashtab, slot); ggc_free (element); } /* Find NODE in SET and return an iterator to it if found. A null iterator is returned if NODE is not in SET. */ cgraph_node_set_iterator cgraph_node_set_find (cgraph_node_set set, struct cgraph_node *node) { void **slot; struct cgraph_node_set_element_def dummy; cgraph_node_set_element element; cgraph_node_set_iterator csi; dummy.node = node; slot = htab_find_slot (set->hashtab, &dummy, NO_INSERT); if (slot == NULL) csi.index = (unsigned) ~0; else { element = (cgraph_node_set_element) *slot; gcc_assert (VEC_index (cgraph_node_ptr, set->nodes, element->index) == node); csi.index = element->index; } csi.set = set; return csi; } /* Dump content of SET to file F. */ void dump_cgraph_node_set (FILE *f, cgraph_node_set set) { cgraph_node_set_iterator iter; for (iter = csi_start (set); !csi_end_p (iter); csi_next (&iter)) { struct cgraph_node *node = csi_node (iter); dump_cgraph_node (f, node); } } /* Dump content of SET to stderr. */ void debug_cgraph_node_set (cgraph_node_set set) { dump_cgraph_node_set (stderr, set); }
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