/* Utilities for ipa analysis. Copyright (C) 2005-2015 Free Software Foundation, Inc. Contributed by Kenneth Zadeck 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 . */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "hash-set.h" #include "machmode.h" #include "vec.h" #include "double-int.h" #include "input.h" #include "alias.h" #include "symtab.h" #include "options.h" #include "wide-int.h" #include "inchash.h" #include "tree.h" #include "fold-const.h" #include "predict.h" #include "hard-reg-set.h" #include "input.h" #include "function.h" #include "dominance.h" #include "cfg.h" #include "basic-block.h" #include "tree-ssa-alias.h" #include "internal-fn.h" #include "gimple-expr.h" #include "is-a.h" #include "gimple.h" #include "tree-inline.h" #include "dumpfile.h" #include "langhooks.h" #include "splay-tree.h" #include "hash-map.h" #include "plugin-api.h" #include "ipa-ref.h" #include "cgraph.h" #include "ipa-utils.h" #include "bitmap.h" #include "ipa-reference.h" #include "flags.h" #include "diagnostic.h" #include "langhooks.h" #include "lto-streamer.h" #include "alloc-pool.h" #include "symbol-summary.h" #include "ipa-prop.h" #include "ipa-inline.h" /* Debugging function for postorder and inorder code. NOTE is a string that is printed before the nodes are printed. ORDER is an array of cgraph_nodes that has COUNT useful nodes in it. */ void ipa_print_order (FILE* out, const char * note, struct cgraph_node** order, int count) { int i; fprintf (out, "\n\n ordered call graph: %s\n", note); for (i = count - 1; i >= 0; i--) order[i]->dump (out); fprintf (out, "\n"); fflush (out); } struct searchc_env { struct cgraph_node **stack; int stack_size; struct cgraph_node **result; int order_pos; splay_tree nodes_marked_new; bool reduce; bool allow_overwritable; int count; }; /* This is an implementation of Tarjan's strongly connected region finder as reprinted in Aho Hopcraft and Ullman's The Design and Analysis of Computer Programs (1975) pages 192-193. This version has been customized for cgraph_nodes. The env parameter is because it is recursive and there are no nested functions here. This function should only be called from itself or ipa_reduced_postorder. ENV is a stack env and would be unnecessary if C had nested functions. V is the node to start searching from. */ static void searchc (struct searchc_env* env, struct cgraph_node *v, bool (*ignore_edge) (struct cgraph_edge *)) { struct cgraph_edge *edge; struct ipa_dfs_info *v_info = (struct ipa_dfs_info *) v->aux; /* mark node as old */ v_info->new_node = false; splay_tree_remove (env->nodes_marked_new, v->uid); v_info->dfn_number = env->count; v_info->low_link = env->count; env->count++; env->stack[(env->stack_size)++] = v; v_info->on_stack = true; for (edge = v->callees; edge; edge = edge->next_callee) { struct ipa_dfs_info * w_info; enum availability avail; struct cgraph_node *w = edge->callee->ultimate_alias_target (&avail); if (!w || (ignore_edge && ignore_edge (edge))) continue; if (w->aux && (avail > AVAIL_INTERPOSABLE || (env->allow_overwritable && avail == AVAIL_INTERPOSABLE))) { w_info = (struct ipa_dfs_info *) w->aux; if (w_info->new_node) { searchc (env, w, ignore_edge); v_info->low_link = (v_info->low_link < w_info->low_link) ? v_info->low_link : w_info->low_link; } else if ((w_info->dfn_number < v_info->dfn_number) && (w_info->on_stack)) v_info->low_link = (w_info->dfn_number < v_info->low_link) ? w_info->dfn_number : v_info->low_link; } } if (v_info->low_link == v_info->dfn_number) { struct cgraph_node *last = NULL; struct cgraph_node *x; struct ipa_dfs_info *x_info; do { x = env->stack[--(env->stack_size)]; x_info = (struct ipa_dfs_info *) x->aux; x_info->on_stack = false; x_info->scc_no = v_info->dfn_number; if (env->reduce) { x_info->next_cycle = last; last = x; } else env->result[env->order_pos++] = x; } while (v != x); if (env->reduce) env->result[env->order_pos++] = v; } } /* Topsort the call graph by caller relation. Put the result in ORDER. The REDUCE flag is true if you want the cycles reduced to single nodes. You can use ipa_get_nodes_in_cycle to obtain a vector containing all real call graph nodes in a reduced node. Set ALLOW_OVERWRITABLE if nodes with such availability should be included. IGNORE_EDGE, if non-NULL is a hook that may make some edges insignificant for the topological sort. */ int ipa_reduced_postorder (struct cgraph_node **order, bool reduce, bool allow_overwritable, bool (*ignore_edge) (struct cgraph_edge *)) { struct cgraph_node *node; struct searchc_env env; splay_tree_node result; env.stack = XCNEWVEC (struct cgraph_node *, symtab->cgraph_count); env.stack_size = 0; env.result = order; env.order_pos = 0; env.nodes_marked_new = splay_tree_new (splay_tree_compare_ints, 0, 0); env.count = 1; env.reduce = reduce; env.allow_overwritable = allow_overwritable; FOR_EACH_DEFINED_FUNCTION (node) { enum availability avail = node->get_availability (); if (avail > AVAIL_INTERPOSABLE || (allow_overwritable && (avail == AVAIL_INTERPOSABLE))) { /* Reuse the info if it is already there. */ struct ipa_dfs_info *info = (struct ipa_dfs_info *) node->aux; if (!info) info = XCNEW (struct ipa_dfs_info); info->new_node = true; info->on_stack = false; info->next_cycle = NULL; node->aux = info; splay_tree_insert (env.nodes_marked_new, (splay_tree_key)node->uid, (splay_tree_value)node); } else node->aux = NULL; } result = splay_tree_min (env.nodes_marked_new); while (result) { node = (struct cgraph_node *)result->value; searchc (&env, node, ignore_edge); result = splay_tree_min (env.nodes_marked_new); } splay_tree_delete (env.nodes_marked_new); free (env.stack); return env.order_pos; } /* Deallocate all ipa_dfs_info structures pointed to by the aux pointer of call graph nodes. */ void ipa_free_postorder_info (void) { struct cgraph_node *node; FOR_EACH_DEFINED_FUNCTION (node) { /* Get rid of the aux information. */ if (node->aux) { free (node->aux); node->aux = NULL; } } } /* Get the set of nodes for the cycle in the reduced call graph starting from NODE. */ vec ipa_get_nodes_in_cycle (struct cgraph_node *node) { vec v = vNULL; struct ipa_dfs_info *node_dfs_info; while (node) { v.safe_push (node); node_dfs_info = (struct ipa_dfs_info *) node->aux; node = node_dfs_info->next_cycle; } return v; } /* Return true iff the CS is an edge within a strongly connected component as computed by ipa_reduced_postorder. */ bool ipa_edge_within_scc (struct cgraph_edge *cs) { struct ipa_dfs_info *caller_dfs = (struct ipa_dfs_info *) cs->caller->aux; struct ipa_dfs_info *callee_dfs; struct cgraph_node *callee = cs->callee->function_symbol (); callee_dfs = (struct ipa_dfs_info *) callee->aux; return (caller_dfs && callee_dfs && caller_dfs->scc_no == callee_dfs->scc_no); } struct postorder_stack { struct cgraph_node *node; struct cgraph_edge *edge; int ref; }; /* Fill array order with all nodes with output flag set in the reverse topological order. Return the number of elements in the array. FIXME: While walking, consider aliases, too. */ int ipa_reverse_postorder (struct cgraph_node **order) { struct cgraph_node *node, *node2; int stack_size = 0; int order_pos = 0; struct cgraph_edge *edge; int pass; struct ipa_ref *ref = NULL; struct postorder_stack *stack = XCNEWVEC (struct postorder_stack, symtab->cgraph_count); /* 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_EACH_FUNCTION (node) node->aux = NULL; for (pass = 0; pass < 2; pass++) FOR_EACH_FUNCTION (node) if (!node->aux && (pass || (!node->address_taken && !node->global.inlined_to && !node->alias && !node->thunk.thunk_p && !node->only_called_directly_p ()))) { stack_size = 0; stack[stack_size].node = node; stack[stack_size].edge = node->callers; stack[stack_size].ref = 0; node->aux = (void *)(size_t)1; while (stack_size >= 0) { while (true) { node2 = NULL; while (stack[stack_size].edge && !node2) { edge = stack[stack_size].edge; node2 = edge->caller; stack[stack_size].edge = edge->next_caller; /* Break possible cycles involving always-inline functions by ignoring edges from always-inline functions to non-always-inline functions. */ if (DECL_DISREGARD_INLINE_LIMITS (edge->caller->decl) && !DECL_DISREGARD_INLINE_LIMITS (edge->callee->function_symbol ()->decl)) node2 = NULL; } for (; stack[stack_size].node->iterate_referring ( stack[stack_size].ref, ref) && !node2; stack[stack_size].ref++) { if (ref->use == IPA_REF_ALIAS) node2 = dyn_cast (ref->referring); } if (!node2) break; if (!node2->aux) { stack[++stack_size].node = node2; stack[stack_size].edge = node2->callers; stack[stack_size].ref = 0; node2->aux = (void *)(size_t)1; } } order[order_pos++] = stack[stack_size--].node; } } free (stack); FOR_EACH_FUNCTION (node) node->aux = NULL; return order_pos; } /* Given a memory reference T, will return the variable at the bottom of the access. Unlike get_base_address, this will recurse through INDIRECT_REFS. */ tree get_base_var (tree t) { while (!SSA_VAR_P (t) && (!CONSTANT_CLASS_P (t)) && TREE_CODE (t) != LABEL_DECL && TREE_CODE (t) != FUNCTION_DECL && TREE_CODE (t) != CONST_DECL && TREE_CODE (t) != CONSTRUCTOR) { t = TREE_OPERAND (t, 0); } return t; } /* SRC and DST are going to be merged. Take SRC's profile and merge it into DST so it is not going to be lost. Possibly destroy SRC's body on the way unless PRESERVE_BODY is set. */ void ipa_merge_profiles (struct cgraph_node *dst, struct cgraph_node *src, bool preserve_body) { tree oldsrcdecl = src->decl; struct function *srccfun, *dstcfun; bool match = true; if (!src->definition || !dst->definition) return; if (src->frequency < dst->frequency) src->frequency = dst->frequency; /* Time profiles are merged. */ if (dst->tp_first_run > src->tp_first_run && src->tp_first_run) dst->tp_first_run = src->tp_first_run; if (src->profile_id && !dst->profile_id) dst->profile_id = src->profile_id; if (!dst->count) return; if (symtab->dump_file) { fprintf (symtab->dump_file, "Merging profiles of %s/%i to %s/%i\n", xstrdup_for_dump (src->name ()), src->order, xstrdup_for_dump (dst->name ()), dst->order); } dst->count += src->count; /* This is ugly. We need to get both function bodies into memory. If declaration is merged, we need to duplicate it to be able to load body that is being replaced. This makes symbol table temporarily inconsistent. */ if (src->decl == dst->decl) { struct lto_in_decl_state temp; struct lto_in_decl_state *state; /* We are going to move the decl, we want to remove its file decl data. and link these with the new decl. */ temp.fn_decl = src->decl; lto_in_decl_state **slot = src->lto_file_data->function_decl_states->find_slot (&temp, NO_INSERT); state = *slot; src->lto_file_data->function_decl_states->clear_slot (slot); gcc_assert (state); /* Duplicate the decl and be sure it does not link into body of DST. */ src->decl = copy_node (src->decl); DECL_STRUCT_FUNCTION (src->decl) = NULL; DECL_ARGUMENTS (src->decl) = NULL; DECL_INITIAL (src->decl) = NULL; DECL_RESULT (src->decl) = NULL; /* Associate the decl state with new declaration, so LTO streamer can look it up. */ state->fn_decl = src->decl; slot = src->lto_file_data->function_decl_states->find_slot (state, INSERT); gcc_assert (!*slot); *slot = state; } src->get_untransformed_body (); dst->get_untransformed_body (); srccfun = DECL_STRUCT_FUNCTION (src->decl); dstcfun = DECL_STRUCT_FUNCTION (dst->decl); if (n_basic_blocks_for_fn (srccfun) != n_basic_blocks_for_fn (dstcfun)) { if (symtab->dump_file) fprintf (symtab->dump_file, "Giving up; number of basic block mismatch.\n"); match = false; } else if (last_basic_block_for_fn (srccfun) != last_basic_block_for_fn (dstcfun)) { if (symtab->dump_file) fprintf (symtab->dump_file, "Giving up; last block mismatch.\n"); match = false; } else { basic_block srcbb, dstbb; FOR_ALL_BB_FN (srcbb, srccfun) { unsigned int i; dstbb = BASIC_BLOCK_FOR_FN (dstcfun, srcbb->index); if (dstbb == NULL) { if (symtab->dump_file) fprintf (symtab->dump_file, "No matching block for bb %i.\n", srcbb->index); match = false; break; } if (EDGE_COUNT (srcbb->succs) != EDGE_COUNT (dstbb->succs)) { if (symtab->dump_file) fprintf (symtab->dump_file, "Edge count mistmatch for bb %i.\n", srcbb->index); match = false; break; } for (i = 0; i < EDGE_COUNT (srcbb->succs); i++) { edge srce = EDGE_SUCC (srcbb, i); edge dste = EDGE_SUCC (dstbb, i); if (srce->dest->index != dste->dest->index) { if (symtab->dump_file) fprintf (symtab->dump_file, "Succ edge mistmatch for bb %i.\n", srce->dest->index); match = false; break; } } } } if (match) { struct cgraph_edge *e, *e2; basic_block srcbb, dstbb; /* TODO: merge also statement histograms. */ FOR_ALL_BB_FN (srcbb, srccfun) { unsigned int i; dstbb = BASIC_BLOCK_FOR_FN (dstcfun, srcbb->index); dstbb->count += srcbb->count; for (i = 0; i < EDGE_COUNT (srcbb->succs); i++) { edge srce = EDGE_SUCC (srcbb, i); edge dste = EDGE_SUCC (dstbb, i); dste->count += srce->count; } } push_cfun (dstcfun); counts_to_freqs (); compute_function_frequency (); pop_cfun (); for (e = dst->callees; e; e = e->next_callee) { if (e->speculative) continue; e->count = gimple_bb (e->call_stmt)->count; e->frequency = compute_call_stmt_bb_frequency (dst->decl, gimple_bb (e->call_stmt)); } for (e = dst->indirect_calls, e2 = src->indirect_calls; e; e2 = (e2 ? e2->next_callee : NULL), e = e->next_callee) { gcov_type count = gimple_bb (e->call_stmt)->count; int freq = compute_call_stmt_bb_frequency (dst->decl, gimple_bb (e->call_stmt)); /* When call is speculative, we need to re-distribute probabilities the same way as they was. This is not really correct because in the other copy the speculation may differ; but probably it is not really worth the effort. */ if (e->speculative) { cgraph_edge *direct, *indirect; cgraph_edge *direct2 = NULL, *indirect2 = NULL; ipa_ref *ref; e->speculative_call_info (direct, indirect, ref); gcc_assert (e == indirect); if (e2 && e2->speculative) e2->speculative_call_info (direct2, indirect2, ref); if (indirect->count || direct->count) { /* We should mismatch earlier if there is no matching indirect edge. */ if (!e2) { if (dump_file) fprintf (dump_file, "Mismatch in merging indirect edges\n"); } else if (!e2->speculative) indirect->count += e2->count; else if (e2->speculative) { if (DECL_ASSEMBLER_NAME (direct2->callee->decl) != DECL_ASSEMBLER_NAME (direct->callee->decl)) { if (direct2->count >= direct->count) { direct->redirect_callee (direct2->callee); indirect->count += indirect2->count + direct->count; direct->count = direct2->count; } else indirect->count += indirect2->count + direct2->count; } else { direct->count += direct2->count; indirect->count += indirect2->count; } } int prob = RDIV (direct->count * REG_BR_PROB_BASE , direct->count + indirect->count); direct->frequency = RDIV (freq * prob, REG_BR_PROB_BASE); indirect->frequency = RDIV (freq * (REG_BR_PROB_BASE - prob), REG_BR_PROB_BASE); } else /* At the moment we should have only profile feedback based speculations when merging. */ gcc_unreachable (); } else if (e2 && e2->speculative) { cgraph_edge *direct, *indirect; ipa_ref *ref; e2->speculative_call_info (direct, indirect, ref); e->count = count; e->frequency = freq; int prob = RDIV (direct->count * REG_BR_PROB_BASE, e->count); e->make_speculative (direct->callee, direct->count, RDIV (freq * prob, REG_BR_PROB_BASE)); } else { e->count = count; e->frequency = freq; } } if (!preserve_body) src->release_body (); inline_update_overall_summary (dst); } /* TODO: if there is no match, we can scale up. */ src->decl = oldsrcdecl; } /* Return true if call to DEST is known to be self-recusive call withing FUNC. */ bool recursive_call_p (tree func, tree dest) { struct cgraph_node *dest_node = cgraph_node::get_create (dest); struct cgraph_node *cnode = cgraph_node::get_create (func); return dest_node->semantically_equivalent_p (cnode); }