/* Inlining decision heuristics. Copyright (C) 2003, 2004, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. Contributed by Jan Hubicka 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 . */ /* Inlining decision heuristics We separate inlining decisions from the inliner itself and store it inside callgraph as so called inline plan. Refer to cgraph.c documentation about particular representation of inline plans in the callgraph. There are three major parts of this file: cgraph_mark_inline_edge implementation This function allows to mark given call inline and performs necessary modifications of cgraph (production of the clones and updating overall statistics) inlining heuristics limits These functions allow to check that particular inlining is allowed by the limits specified by user (allowed function growth, overall unit growth and so on). inlining heuristics This is implementation of IPA pass aiming to get as much of benefit from inlining obeying the limits checked above. The implementation of particular heuristics is separated from the rest of code to make it easier to replace it with more complicated implementation in the future. The rest of inlining code acts as a library aimed to modify the callgraph and verify that the parameters on code size growth fits. To mark given call inline, use cgraph_mark_inline function, the verification is performed by cgraph_default_inline_p and cgraph_check_inline_limits. The heuristics implements simple knapsack style algorithm ordering all functions by their "profitability" (estimated by code size growth) and inlining them in priority order. cgraph_decide_inlining implements heuristics taking whole callgraph into account, while cgraph_decide_inlining_incrementally considers only one function at a time and is used by early inliner. The inliner itself is split into several passes: pass_inline_parameters This pass computes local properties of functions that are used by inliner: estimated function body size, whether function is inlinable at all and stack frame consumption. Before executing any of inliner passes, this local pass has to be applied to each function in the callgraph (ie run as subpass of some earlier IPA pass). The results are made out of date by any optimization applied on the function body. pass_early_inlining Simple local inlining pass inlining callees into current function. This pass makes no global whole compilation unit analysis and this when allowed to do inlining expanding code size it might result in unbounded growth of whole unit. The pass is run during conversion into SSA form. Only functions already converted into SSA form are inlined, so the conversion must happen in topological order on the callgraph (that is maintained by pass manager). The functions after inlining are early optimized so the early inliner sees unoptimized function itself, but all considered callees are already optimized allowing it to unfold abstraction penalty on C++ effectively and cheaply. pass_ipa_inline This is the main pass implementing simple greedy algorithm to do inlining of small functions that results in overall growth of compilation unit and inlining of functions called once. The pass compute just so called inline plan (representation of inlining to be done in callgraph) and unlike early inlining it is not performing the inlining itself. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "tree-inline.h" #include "langhooks.h" #include "flags.h" #include "cgraph.h" #include "diagnostic.h" #include "gimple-pretty-print.h" #include "timevar.h" #include "params.h" #include "fibheap.h" #include "intl.h" #include "tree-pass.h" #include "hashtab.h" #include "coverage.h" #include "ggc.h" #include "tree-flow.h" #include "rtl.h" #include "ipa-prop.h" #include "basic-block.h" #include "toplev.h" #include "dbgcnt.h" #include "except.h" #include "l-ipo.h" #define MAX_TIME 1000000000 /* Mode incremental inliner operate on: In ALWAYS_INLINE only functions marked always_inline are inlined. This mode is used after detecting cycle during flattening. In SIZE mode, only functions that reduce function body size after inlining are inlined, this is used during early inlining. in ALL mode, everything is inlined. This is used during flattening. */ enum inlining_mode { INLINE_NONE = 0, INLINE_ALWAYS_INLINE, INLINE_SIZE_NORECURSIVE, INLINE_SIZE, INLINE_ALL }; static bool cgraph_decide_inlining_incrementally (struct cgraph_node *, enum inlining_mode); static void cgraph_flatten (struct cgraph_node *node); /* Statistics we collect about inlining algorithm. */ static int ncalls_inlined; static int nfunctions_inlined; static int overall_size; static gcov_type max_count, max_benefit; /* Holders of ipa cgraph hooks: */ static struct cgraph_node_hook_list *function_insertion_hook_holder; static inline struct inline_summary * inline_summary (struct cgraph_node *node) { return &node->local.inline_summary; } /* Estimate self time of the function after inlining WHAT into TO. */ static int cgraph_estimate_time_after_inlining (int frequency, struct cgraph_node *to, struct cgraph_node *what) { gcov_type time = (((gcov_type)what->global.time - inline_summary (what)->time_inlining_benefit) * frequency + CGRAPH_FREQ_BASE / 2) / CGRAPH_FREQ_BASE + to->global.time; if (time < 0) time = 0; if (time > MAX_TIME) time = MAX_TIME; return time; } /* Estimate self size of the function after inlining WHAT into TO. */ static inline int cgraph_estimate_size_after_inlining (struct cgraph_node *to, struct cgraph_node *what) { int size = ((what->global.size - inline_summary (what)->size_inlining_benefit) + to->global.size); gcc_assert (size >= 0); return size; } /* Scale frequency of NODE edges by FREQ_SCALE and increase loop nest by NEST. */ static void update_noncloned_frequencies (struct cgraph_node *node, int freq_scale, int nest) { struct cgraph_edge *e; /* We do not want to ignore high loop nest after freq drops to 0. */ if (!freq_scale) freq_scale = 1; for (e = node->callees; e; e = e->next_callee) { e->loop_nest += nest; e->frequency = e->frequency * (gcov_type) freq_scale / CGRAPH_FREQ_BASE; if (e->frequency > CGRAPH_FREQ_MAX) e->frequency = CGRAPH_FREQ_MAX; if (!e->inline_failed) update_noncloned_frequencies (e->callee, freq_scale, nest); } } /* E is expected to be an edge being inlined. Clone destination node of the edge and redirect it to the new clone. DUPLICATE is used for bookkeeping on whether we are actually creating new clones or re-using node originally representing out-of-line function call. */ void cgraph_clone_inlined_nodes (struct cgraph_edge *e, bool duplicate, bool update_original) { if (duplicate) { /* We may eliminate the need for out-of-line copy to be output. In that case just go ahead and re-use it. */ if (!e->callee->callers->next_caller /* Recursive inlining never wants the master clone to be overwritten. */ && update_original /* FIXME: When address is taken of DECL_EXTERNAL function we still can remove its offline copy, but we would need to keep unanalyzed node in the callgraph so references can point to it. */ && !e->callee->address_taken && cgraph_can_remove_if_no_direct_calls_p (e->callee) /* Inlining might enable more devirtualizing, so we want to remove those only after all devirtualizable virtual calls are processed. Lacking may edges in callgraph we just preserve them post inlining. */ && (!DECL_VIRTUAL_P (e->callee->decl) || (!DECL_COMDAT (e->callee->decl) && !DECL_EXTERNAL (e->callee->decl))) /* Don't reuse if more than one function shares a comdat group. If the other function(s) are needed, we need to emit even this function out of line. */ && !e->callee->same_comdat_group && !cgraph_new_nodes) { gcc_assert (!e->callee->global.inlined_to); if (e->callee->analyzed && !DECL_EXTERNAL (e->callee->decl)) { overall_size -= e->callee->global.size; nfunctions_inlined++; } duplicate = false; e->callee->local.externally_visible = false; update_noncloned_frequencies (e->callee, e->frequency, e->loop_nest); } else { struct cgraph_node *n; n = cgraph_clone_node (e->callee, e->callee->decl, e->count, e->frequency, e->loop_nest, update_original, NULL); cgraph_redirect_edge_callee (e, n); } } if (e->caller->global.inlined_to) e->callee->global.inlined_to = e->caller->global.inlined_to; else e->callee->global.inlined_to = e->caller; /* Pessimistically assume no sharing of stack space. That is, the frame size of a function is estimated as the original frame size plus the sum of the frame sizes of all inlined callees. */ e->callee->global.inlined_to->global.estimated_stack_size += inline_summary (e->callee)->estimated_self_stack_size; cgraph_propagate_frequency (e->callee); /* Recursively clone all bodies. */ for (e = e->callee->callees; e; e = e->next_callee) if (!e->inline_failed) cgraph_clone_inlined_nodes (e, duplicate, update_original); } #define MAX_INT_LENGTH 16 /* Return NODE's name and aux info. The output is controled by OPT_INFO level. */ static const char * cgraph_node_opt_info (struct cgraph_node *node) { char *buf; size_t buf_size; const char *bfd_name = lang_hooks.dwarf_name (node->decl, 0); if (!bfd_name) bfd_name = "unknown"; buf_size = strlen (bfd_name) + 1; if (profile_info) buf_size += (2 * MAX_INT_LENGTH + 5); buf = (char *) xmalloc (buf_size); strcpy (buf, bfd_name); if (profile_info) sprintf (buf, "%s ("HOST_WIDEST_INT_PRINT_DEC", "HOST_WIDEST_INT_PRINT_DEC")", buf, node->count, node->max_bb_count); return buf; } /* Return CALLER's inlined call chain. Save the cgraph_node of the ultimate function that the caller is inlined to in FINAL_CALLER. */ static const char * cgraph_node_call_chain (struct cgraph_node *caller, struct cgraph_node **final_caller) { struct cgraph_node *node; const char *via_str = " (via inline instance"; size_t current_string_len = strlen (via_str) + 1; size_t buf_size = current_string_len; char *buf = (char *) xmalloc (buf_size); buf[0] = 0; gcc_assert (caller->global.inlined_to != NULL); strcat (buf, via_str); for (node = caller; node->global.inlined_to != NULL; node = node->callers->caller) { const char *name = cgraph_node_opt_info (node); current_string_len += (strlen (name) + 1); if (current_string_len >= buf_size) { buf_size = current_string_len * 2; buf = (char *) xrealloc (buf, buf_size); } strcat (buf, " "); strcat (buf, name); } strcat (buf, ")"); *final_caller = node; return buf; } /* File static variable to denote if it is in ipa-inline pass. */ static bool is_in_ipa_inline = false; /* Dump the inline decision of EDGE to stderr. */ static void dump_inline_decision (struct cgraph_edge *edge) { location_t locus; const char *inline_chain_text; const char *call_count_text; struct cgraph_node *final_caller = edge->caller; if (flag_opt_info < OPT_INFO_MED && !is_in_ipa_inline) return; if (final_caller->global.inlined_to != NULL) inline_chain_text = cgraph_node_call_chain (final_caller, &final_caller); else inline_chain_text = ""; if (edge->count > 0) { const char *call_count_str = " with call count "; char *buf = (char *) xmalloc (strlen (call_count_str) + MAX_INT_LENGTH); sprintf (buf, "%s"HOST_WIDEST_INT_PRINT_DEC, call_count_str, edge->count); call_count_text = buf; } else { call_count_text = ""; } locus = gimple_location (edge->call_stmt); inform (locus, "%s inlined into %s%s%s", cgraph_node_opt_info (edge->callee), cgraph_node_opt_info (final_caller), call_count_text, inline_chain_text); } /* Mark edge E as inlined and update callgraph accordingly. UPDATE_ORIGINAL specify whether profile of original function should be updated. If any new indirect edges are discovered in the process, add them to NEW_EDGES, unless it is NULL. Return true iff any new callgraph edges were discovered as a result of inlining. */ static bool cgraph_mark_inline_edge (struct cgraph_edge *e, bool update_original, VEC (cgraph_edge_p, heap) **new_edges) { int old_size = 0, new_size = 0; struct cgraph_node *to = NULL, *what; struct cgraph_edge *curr = e; int freq; /* Skip fake edge. */ if (L_IPO_COMP_MODE && !e->call_stmt) return false; if (flag_opt_info >= OPT_INFO_MIN) dump_inline_decision (e); /* Don't inline inlined edges. */ gcc_assert (e->inline_failed); /* Don't even think of inlining inline clone. */ gcc_assert (!e->callee->global.inlined_to); e->inline_failed = CIF_OK; DECL_POSSIBLY_INLINED (e->callee->decl) = true; cgraph_clone_inlined_nodes (e, true, update_original); what = e->callee; freq = e->frequency; /* Now update size of caller and all functions caller is inlined into. */ for (;e && !e->inline_failed; e = e->caller->callers) { to = e->caller; old_size = e->caller->global.size; new_size = cgraph_estimate_size_after_inlining (to, what); to->global.size = new_size; to->global.time = cgraph_estimate_time_after_inlining (freq, to, what); if (to->max_bb_count < e->callee->max_bb_count) to->max_bb_count = e->callee->max_bb_count; } gcc_assert (what->global.inlined_to == to); if (new_size > old_size) overall_size += new_size - old_size; ncalls_inlined++; /* FIXME: We should remove the optimize check after we ensure we never run IPA passes when not optimizing. */ if (flag_indirect_inlining && optimize) return ipa_propagate_indirect_call_infos (curr, new_edges); else return false; } /* Estimate the growth caused by inlining NODE into all callees. */ static int cgraph_estimate_growth (struct cgraph_node *node) { int growth = 0; struct cgraph_edge *e; bool self_recursive = false; if (node->global.estimated_growth != INT_MIN) return node->global.estimated_growth; for (e = node->callers; e; e = e->next_caller) { if (e->caller == node) self_recursive = true; if (e->inline_failed) growth += (cgraph_estimate_size_after_inlining (e->caller, node) - e->caller->global.size); } /* ??? Wrong for non-trivially self recursive functions or cases where we decide to not inline for different reasons, but it is not big deal as in that case we will keep the body around, but we will also avoid some inlining. */ if (cgraph_will_be_removed_from_program_if_no_direct_calls (node) && !DECL_EXTERNAL (node->decl) && !self_recursive) growth -= node->global.size; /* COMDAT functions are very often not shared across multiple units since they come from various template instantiations. Take this into account. */ else if (DECL_COMDAT (node->decl) && !self_recursive && cgraph_can_remove_if_no_direct_calls_p (node)) growth -= (node->global.size * (100 - PARAM_VALUE (PARAM_COMDAT_SHARING_PROBABILITY)) + 50) / 100; node->global.estimated_growth = growth; return growth; } /* Return false when inlining WHAT into TO is not good idea as it would cause too large growth of function bodies. When ONE_ONLY is true, assume that only one call site is going to be inlined, otherwise figure out how many call sites in TO calls WHAT and verify that all can be inlined. */ static bool cgraph_check_inline_limits (struct cgraph_node *to, struct cgraph_node *what, cgraph_inline_failed_t *reason) { int newsize; int limit; HOST_WIDE_INT stack_size_limit, inlined_stack; if (to->global.inlined_to) to = to->global.inlined_to; /* When inlining large function body called once into small function, take the inlined function as base for limiting the growth. */ if (inline_summary (to)->self_size > inline_summary(what)->self_size) limit = inline_summary (to)->self_size; else limit = inline_summary (what)->self_size; limit += limit * PARAM_VALUE (PARAM_LARGE_FUNCTION_GROWTH) / 100; /* Check the size after inlining against the function limits. But allow the function to shrink if it went over the limits by forced inlining. */ newsize = cgraph_estimate_size_after_inlining (to, what); if (newsize >= to->global.size && newsize > PARAM_VALUE (PARAM_LARGE_FUNCTION_INSNS) && newsize > limit) { if (reason) *reason = CIF_LARGE_FUNCTION_GROWTH_LIMIT; return false; } stack_size_limit = inline_summary (to)->estimated_self_stack_size; stack_size_limit += stack_size_limit * PARAM_VALUE (PARAM_STACK_FRAME_GROWTH) / 100; inlined_stack = (to->global.estimated_stack_size + what->global.estimated_stack_size); if (inlined_stack > stack_size_limit && inlined_stack > PARAM_VALUE (PARAM_LARGE_STACK_FRAME)) { if (reason) *reason = CIF_LARGE_STACK_FRAME_GROWTH_LIMIT; return false; } return true; } /* Return true when function N is small enough to be inlined. */ static bool cgraph_default_inline_p (struct cgraph_node *n, cgraph_inline_failed_t *reason) { tree decl = n->decl; if (n->local.disregard_inline_limits) return true; if (!flag_inline_small_functions && !DECL_DECLARED_INLINE_P (decl)) { if (reason) *reason = CIF_FUNCTION_NOT_INLINE_CANDIDATE; return false; } if (!n->analyzed) { if (reason) *reason = CIF_BODY_NOT_AVAILABLE; return false; } if (cgraph_function_body_availability (n) <= AVAIL_OVERWRITABLE) { if (reason) *reason = CIF_OVERWRITABLE; return false; } if (DECL_DECLARED_INLINE_P (decl)) { if (n->global.size >= MAX_INLINE_INSNS_SINGLE) { if (reason) *reason = CIF_MAX_INLINE_INSNS_SINGLE_LIMIT; return false; } } else { if (n->global.size >= MAX_INLINE_INSNS_AUTO) { if (reason) *reason = CIF_MAX_INLINE_INSNS_AUTO_LIMIT; return false; } } return true; } /* Return true when inlining WHAT would create recursive inlining. We call recursive inlining all cases where same function appears more than once in the single recursion nest path in the inline graph. */ static inline bool cgraph_recursive_inlining_p (struct cgraph_node *to, struct cgraph_node *what, cgraph_inline_failed_t *reason) { bool recursive; if (to->global.inlined_to) recursive = what->decl == to->global.inlined_to->decl; else recursive = what->decl == to->decl; /* Marking recursive function inline has sane semantic and thus we should not warn on it. */ if (recursive && reason) *reason = (what->local.disregard_inline_limits ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED); return recursive; } /* Return true if FUNCDECL is a function with fixed argument list. */ static bool fixed_arg_function_p (tree fndecl) { tree fntype = TREE_TYPE (fndecl); return (TYPE_ARG_TYPES (fntype) == 0 || (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype))) == void_type_node)); } /* For profile collection with flag_dyn_ipa (LIPO), we always want to inline comdat functions for the following reasons: 1) Functions in comdat may be actually defined in a different module (depending on how linker picks). This results in a edge from one module to another module in the dynamic callgraph. The edge is false and result in unnecessary module grouping. 2) The profile counters in comdat functions are not 'comdated' -- which means each copy of the same comdat function has its own set of counters. With inlining, we are actually splitting the counters and make the profile information 'context sensitive', which is a good thing. 3) During profile-use pass of LIPO (flag_dyn_ipa == 1), the pre-tree_profile inline decisions have to be the same as the profile-gen pass (otherwise coverage mismatch will occur). Due to this reason, it is better for each module to 'use' the comdat copy of its own. The only way to get profile data for the copy is to inline the copy in profile-gen phase. TODO: For indirectly called comdat functions, the above issues still exist. */ static bool better_inline_comdat_function_p (struct cgraph_node *node) { return (profile_arc_flag && flag_dyn_ipa && DECL_COMDAT (node->decl) && node->global.size <= PARAM_VALUE (PARAM_MAX_INLINE_INSNS_SINGLE) && fixed_arg_function_p (node->decl)); } /* A cost model driving the inlining heuristics in a way so the edges with smallest badness are inlined first. After each inlining is performed the costs of all caller edges of nodes affected are recomputed so the metrics may accurately depend on values such as number of inlinable callers of the function or function body size. */ static int cgraph_edge_badness (struct cgraph_edge *edge, bool dump) { gcov_type badness; int growth = (cgraph_estimate_size_after_inlining (edge->caller, edge->callee) - edge->caller->global.size); if (edge->callee->local.disregard_inline_limits) return INT_MIN; if (dump) { fprintf (dump_file, " Badness calculation for %s -> %s\n", cgraph_node_name (edge->caller), cgraph_node_name (edge->callee)); fprintf (dump_file, " growth %i, time %i-%i, size %i-%i\n", growth, edge->callee->global.time, inline_summary (edge->callee)->time_inlining_benefit, edge->callee->global.size, inline_summary (edge->callee)->size_inlining_benefit); } /* Always prefer inlining saving code size. */ if (growth <= 0) { badness = INT_MIN - growth; if (dump) fprintf (dump_file, " %i: Growth %i < 0\n", (int) badness, growth); } /* When profiling is available, base priorities -(#calls / growth). So we optimize for overall number of "executed" inlined calls. */ else if (max_count) { badness = ((int) ((double) edge->count * INT_MIN / max_count / (max_benefit + 1)) * (inline_summary (edge->callee)->time_inlining_benefit + 1)) / growth; if (dump) { fprintf (dump_file, " %i (relative %f): profile info. Relative count %f" " * Relative benefit %f\n", (int) badness, (double) badness / INT_MIN, (double) edge->count / max_count, (double) (inline_summary (edge->callee)-> time_inlining_benefit + 1) / (max_benefit + 1)); } } /* When function local profile is available, base priorities on growth / frequency, so we optimize for overall frequency of inlined calls. This is not too accurate since while the call might be frequent within function, the function itself is infrequent. Other objective to optimize for is number of different calls inlined. We add the estimated growth after inlining all functions to bias the priorities slightly in this direction (so fewer times called functions of the same size gets priority). */ else if (flag_guess_branch_prob) { int div = edge->frequency * 100 / CGRAPH_FREQ_BASE + 1; int benefitperc; int growth_for_all; badness = growth * 10000; benefitperc = MIN (100 * inline_summary (edge->callee)->time_inlining_benefit / (edge->callee->global.time + 1) +1, 100); div *= benefitperc; /* Decrease badness if call is nested. */ /* Compress the range so we don't overflow. */ if (div > 10000) div = 10000 + ceil_log2 (div) - 8; if (div < 1) div = 1; if (badness > 0) badness /= div; growth_for_all = cgraph_estimate_growth (edge->callee); badness += growth_for_all; if (badness > INT_MAX) badness = INT_MAX; if (dump) { fprintf (dump_file, " %i: guessed profile. frequency %i, overall growth %i," " benefit %i%%, divisor %i\n", (int) badness, edge->frequency, growth_for_all, benefitperc, div); } } /* When function local profile is not available or it does not give useful information (ie frequency is zero), base the cost on loop nest and overall size growth, so we optimize for overall number of functions fully inlined in program. */ else { int nest = MIN (edge->loop_nest, 8); badness = cgraph_estimate_growth (edge->callee) * 256; /* Decrease badness if call is nested. */ if (badness > 0) badness >>= nest; else { badness <<= nest; } if (dump) fprintf (dump_file, " %i: no profile. nest %i\n", (int) badness, nest); } /* Ensure that we did not overflow in all the fixed point math above. */ gcc_assert (badness >= INT_MIN); gcc_assert (badness <= INT_MAX - 1); /* Make recursive inlining happen always after other inlining is done. */ if (cgraph_recursive_inlining_p (edge->caller, edge->callee, NULL)) return badness + 1; else { if (better_inline_comdat_function_p (edge->callee)) return INT_MIN + 1; else return badness; } } /* Recompute badness of EDGE and update its key in HEAP if needed. */ static void update_edge_key (fibheap_t heap, struct cgraph_edge *edge) { int badness = cgraph_edge_badness (edge, false); if (edge->aux) { fibnode_t n = (fibnode_t) edge->aux; gcc_checking_assert (n->data == edge); /* fibheap_replace_key only decrease the keys. When we increase the key we do not update heap and instead re-insert the element once it becomes a minimum of heap. */ if (badness < n->key) { fibheap_replace_key (heap, n, badness); gcc_checking_assert (n->key == badness); } } else edge->aux = fibheap_insert (heap, badness, edge); } /* Recompute heap nodes for each of caller edge. */ static void update_caller_keys (fibheap_t heap, struct cgraph_node *node, bitmap updated_nodes) { struct cgraph_edge *edge; cgraph_inline_failed_t failed_reason; if (!node->local.inlinable || cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE || node->global.inlined_to) return; if (!bitmap_set_bit (updated_nodes, node->uid)) return; node->global.estimated_growth = INT_MIN; /* See if there is something to do. */ for (edge = node->callers; edge; edge = edge->next_caller) if (edge->inline_failed) break; if (!edge) return; /* Prune out edges we won't inline into anymore. */ if (!cgraph_default_inline_p (node, &failed_reason) && !better_inline_comdat_function_p (node)) { for (; edge; edge = edge->next_caller) if (edge->aux) { fibheap_delete_node (heap, (fibnode_t) edge->aux); edge->aux = NULL; if (edge->inline_failed) edge->inline_failed = failed_reason; } return; } for (; edge; edge = edge->next_caller) if (edge->inline_failed) update_edge_key (heap, edge); } /* Recompute heap nodes for each uninlined call. This is used when we know that edge badnesses are going only to increase (we introduced new call site) and thus all we need is to insert newly created edges into heap. */ static void update_callee_keys (fibheap_t heap, struct cgraph_node *node, bitmap updated_nodes) { struct cgraph_edge *e = node->callees; node->global.estimated_growth = INT_MIN; if (!e) return; while (true) if (!e->inline_failed && e->callee->callees) e = e->callee->callees; else { if (e->inline_failed && e->callee->local.inlinable && cgraph_function_body_availability (e->callee) >= AVAIL_AVAILABLE && !bitmap_bit_p (updated_nodes, e->callee->uid)) { node->global.estimated_growth = INT_MIN; /* If function becomes uninlinable, we need to remove it from the heap. */ if (!cgraph_default_inline_p (e->callee, &e->inline_failed)) update_caller_keys (heap, e->callee, updated_nodes); else /* Otherwise update just edge E. */ update_edge_key (heap, e); } if (e->next_callee) e = e->next_callee; else { do { if (e->caller == node) return; e = e->caller->callers; } while (!e->next_callee); e = e->next_callee; } } } /* Recompute heap nodes for each of caller edges of each of callees. Walk recursively into all inline clones. */ static void update_all_callee_keys (fibheap_t heap, struct cgraph_node *node, bitmap updated_nodes) { struct cgraph_edge *e = node->callees; node->global.estimated_growth = INT_MIN; if (!e) return; while (true) if (!e->inline_failed && e->callee->callees) e = e->callee->callees; else { if (e->inline_failed) update_caller_keys (heap, e->callee, updated_nodes); if (e->next_callee) e = e->next_callee; else { do { if (e->caller == node) return; e = e->caller->callers; } while (!e->next_callee); e = e->next_callee; } } } /* Enqueue all recursive calls from NODE into priority queue depending on how likely we want to recursively inline the call. */ static void lookup_recursive_calls (struct cgraph_node *node, struct cgraph_node *where, fibheap_t heap) { static int priority; struct cgraph_edge *e; for (e = where->callees; e; e = e->next_callee) if (e->callee == node) { /* When profile feedback is available, prioritize by expected number of calls. Without profile feedback we maintain simple queue to order candidates via recursive depths. */ fibheap_insert (heap, !max_count ? priority++ : -(e->count / ((max_count + (1<<24) - 1) / (1<<24))), e); } for (e = where->callees; e; e = e->next_callee) if (!e->inline_failed) lookup_recursive_calls (node, e->callee, heap); } /* Decide on recursive inlining: in the case function has recursive calls, inline until body size reaches given argument. If any new indirect edges are discovered in the process, add them to *NEW_EDGES, unless NEW_EDGES is NULL. */ static bool cgraph_decide_recursive_inlining (struct cgraph_node *node, VEC (cgraph_edge_p, heap) **new_edges) { int limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO); int max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO); int probability = PARAM_VALUE (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY); fibheap_t heap; struct cgraph_edge *e; struct cgraph_node *master_clone, *next; int depth = 0; int n = 0; /* It does not make sense to recursively inline always-inline functions as we are going to sorry() on the remaining calls anyway. */ if (node->local.disregard_inline_limits && lookup_attribute ("always_inline", DECL_ATTRIBUTES (node->decl))) return false; if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION (node->decl)) || (!flag_inline_functions && !DECL_DECLARED_INLINE_P (node->decl))) return false; if (DECL_DECLARED_INLINE_P (node->decl)) { limit = PARAM_VALUE (PARAM_MAX_INLINE_INSNS_RECURSIVE); max_depth = PARAM_VALUE (PARAM_MAX_INLINE_RECURSIVE_DEPTH); } /* Make sure that function is small enough to be considered for inlining. */ if (!max_depth || cgraph_estimate_size_after_inlining (node, node) >= limit) return false; heap = fibheap_new (); lookup_recursive_calls (node, node, heap); if (fibheap_empty (heap)) { fibheap_delete (heap); return false; } if (dump_file) fprintf (dump_file, " Performing recursive inlining on %s\n", cgraph_node_name (node)); /* We need original clone to copy around. */ master_clone = cgraph_clone_node (node, node->decl, node->count, CGRAPH_FREQ_BASE, 1, false, NULL); for (e = master_clone->callees; e; e = e->next_callee) if (!e->inline_failed) cgraph_clone_inlined_nodes (e, true, false); /* Do the inlining and update list of recursive call during process. */ while (!fibheap_empty (heap) && (cgraph_estimate_size_after_inlining (node, master_clone) <= limit)) { struct cgraph_edge *curr = (struct cgraph_edge *) fibheap_extract_min (heap); struct cgraph_node *cnode; depth = 1; for (cnode = curr->caller; cnode->global.inlined_to; cnode = cnode->callers->caller) if (node->decl == curr->callee->decl) depth++; if (depth > max_depth) { if (dump_file) fprintf (dump_file, " maximal depth reached\n"); continue; } if (max_count && node->count) { if (!cgraph_maybe_hot_edge_p (curr)) { if (dump_file) fprintf (dump_file, " Not inlining cold call\n"); continue; } if (node->count == 0 || curr->count * 100 / node->count < probability) { if (dump_file) fprintf (dump_file, " Probability of edge is too small\n"); continue; } } if (!dbg_cnt (inl)) continue; if (dump_file) { fprintf (dump_file, " Inlining call of depth %i", depth); if (node->count) { fprintf (dump_file, " called approx. %.2f times per call", (double)curr->count / node->count); } fprintf (dump_file, "\n"); } cgraph_redirect_edge_callee (curr, master_clone); cgraph_mark_inline_edge (curr, false, new_edges); lookup_recursive_calls (node, curr->callee, heap); n++; } if (!fibheap_empty (heap) && dump_file) fprintf (dump_file, " Recursive inlining growth limit met.\n"); fibheap_delete (heap); if (dump_file) fprintf (dump_file, "\n Inlined %i times, body grown from size %i to %i, time %i to %i\n", n, master_clone->global.size, node->global.size, master_clone->global.time, node->global.time); /* Remove master clone we used for inlining. We rely that clones inlined into master clone gets queued just before master clone so we don't need recursion. */ for (node = cgraph_nodes; node != master_clone; node = next) { next = node->next; if (node->global.inlined_to == master_clone) cgraph_remove_node (node); } cgraph_remove_node (master_clone); /* FIXME: Recursive inlining actually reduces number of calls of the function. At this place we should probably walk the function and inline clones and compensate the counts accordingly. This probably doesn't matter much in practice. */ return n > 0; } /* Set inline_failed for all callers of given function to REASON. */ static void cgraph_set_inline_failed (struct cgraph_node *node, cgraph_inline_failed_t reason) { struct cgraph_edge *e; if (dump_file) fprintf (dump_file, "Inlining failed: %s\n", cgraph_inline_failed_string (reason)); for (e = node->callers; e; e = e->next_caller) if (e->inline_failed) e->inline_failed = reason; } /* Given whole compilation unit estimate of INSNS, compute how large we can allow the unit to grow. */ static int compute_max_insns (int insns) { int max_insns = insns; if (max_insns < PARAM_VALUE (PARAM_LARGE_UNIT_INSNS)) max_insns = PARAM_VALUE (PARAM_LARGE_UNIT_INSNS); return ((HOST_WIDEST_INT) max_insns * (100 + PARAM_VALUE (PARAM_INLINE_UNIT_GROWTH)) / 100); } /* Compute badness of all edges in NEW_EDGES and add them to the HEAP. */ static void add_new_edges_to_heap (fibheap_t heap, VEC (cgraph_edge_p, heap) *new_edges) { while (VEC_length (cgraph_edge_p, new_edges) > 0) { struct cgraph_edge *edge = VEC_pop (cgraph_edge_p, new_edges); gcc_assert (!edge->aux); if (edge->callee->local.inlinable && edge->inline_failed && cgraph_default_inline_p (edge->callee, &edge->inline_failed)) edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge, false), edge); } } /* Returns true if an edge or its caller are hot enough to be considered for inlining. */ static bool edge_hot_enough_p (struct cgraph_edge *edge) { if (cgraph_maybe_hot_edge_p (edge)) return true; if (flag_inline_hot_caller && maybe_hot_count_p (edge->caller->max_bb_count)) return true; return false; } /* We use greedy algorithm for inlining of small functions: All inline candidates are put into prioritized heap based on estimated growth of the overall number of instructions and then update the estimates. INLINED and INLINED_CALLEES are just pointers to arrays large enough to be passed to cgraph_inlined_into and cgraph_inlined_callees. */ static void cgraph_decide_inlining_of_small_functions (void) { struct cgraph_node *node; struct cgraph_edge *edge; cgraph_inline_failed_t failed_reason; fibheap_t heap = fibheap_new (); bitmap updated_nodes = BITMAP_ALLOC (NULL); int min_size, max_size; VEC (cgraph_edge_p, heap) *new_indirect_edges = NULL; is_in_ipa_inline = true; if (flag_indirect_inlining) new_indirect_edges = VEC_alloc (cgraph_edge_p, heap, 8); if (dump_file) fprintf (dump_file, "\nDeciding on smaller functions:\n"); /* Put all inline candidates into the heap. */ for (node = cgraph_nodes; node; node = node->next) { if (!node->local.inlinable || !node->callers) continue; if (dump_file) fprintf (dump_file, "Considering inline candidate %s.\n", cgraph_node_name (node)); node->global.estimated_growth = INT_MIN; if (!cgraph_default_inline_p (node, &failed_reason) && !better_inline_comdat_function_p (node)) { cgraph_set_inline_failed (node, failed_reason); continue; } for (edge = node->callers; edge; edge = edge->next_caller) if (edge->inline_failed) { gcc_assert (!edge->aux); edge->aux = fibheap_insert (heap, cgraph_edge_badness (edge, false), edge); } } max_size = compute_max_insns (overall_size); min_size = overall_size; while (overall_size <= max_size && !fibheap_empty (heap)) { int old_size = overall_size; struct cgraph_node *where, *callee; int badness = fibheap_min_key (heap); int current_badness; int growth; cgraph_inline_failed_t not_good = CIF_OK; edge = (struct cgraph_edge *) fibheap_extract_min (heap); gcc_assert (edge->aux); edge->aux = NULL; if (!edge->inline_failed) continue; /* When updating the edge costs, we only decrease badness in the keys. When the badness increase, we keep the heap as it is and re-insert key now. */ current_badness = cgraph_edge_badness (edge, false); gcc_assert (current_badness >= badness); if (current_badness != badness) { edge->aux = fibheap_insert (heap, current_badness, edge); continue; } callee = edge->callee; growth = (cgraph_estimate_size_after_inlining (edge->caller, edge->callee) - edge->caller->global.size); if (dump_file) { fprintf (dump_file, "\nConsidering %s with %i size\n", cgraph_node_name (edge->callee), edge->callee->global.size); fprintf (dump_file, " to be inlined into %s in %s:%i\n" " Estimated growth after inlined into all callees is %+i insns.\n" " Estimated badness is %i, frequency %.2f.\n", cgraph_node_name (edge->caller), flag_wpa ? "unknown" : gimple_filename ((const_gimple) edge->call_stmt), flag_wpa ? -1 : gimple_lineno ((const_gimple) edge->call_stmt), cgraph_estimate_growth (edge->callee), badness, edge->frequency / (double)CGRAPH_FREQ_BASE); if (edge->count) fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", edge->count); if (dump_flags & TDF_DETAILS) cgraph_edge_badness (edge, true); } /* When not having profile info ready we don't weight by any way the position of call in procedure itself. This means if call of function A from function B seems profitable to inline, the recursive call of function A in inline copy of A in B will look profitable too and we end up inlining until reaching maximal function growth. This is not good idea so prohibit the recursive inlining. ??? When the frequencies are taken into account we might not need this restriction. We need to be careful here, in some testcases, e.g. directives.c in libcpp, we can estimate self recursive function to have negative growth for inlining completely. */ if (!edge->count) { where = edge->caller; while (where->global.inlined_to) { if (where->decl == edge->callee->decl) break; where = where->callers->caller; } if (where->global.inlined_to) { edge->inline_failed = (edge->callee->local.disregard_inline_limits ? CIF_RECURSIVE_INLINING : CIF_UNSPECIFIED); if (dump_file) fprintf (dump_file, " inline_failed:Recursive inlining performed only for function itself.\n"); continue; } } if (edge->callee->local.disregard_inline_limits) ; else if (!edge_hot_enough_p (edge)) not_good = CIF_UNLIKELY_CALL; else if (!flag_inline_functions && !DECL_DECLARED_INLINE_P (edge->callee->decl)) not_good = CIF_NOT_DECLARED_INLINED; else if (optimize_function_for_size_p (DECL_STRUCT_FUNCTION(edge->caller->decl))) not_good = CIF_OPTIMIZING_FOR_SIZE; if (not_good && growth > 0 && cgraph_estimate_growth (edge->callee) > 0) { if (!cgraph_recursive_inlining_p (edge->caller, edge->callee, &edge->inline_failed)) { edge->inline_failed = not_good; if (dump_file) fprintf (dump_file, " inline_failed:%s.\n", cgraph_inline_failed_string (edge->inline_failed)); } continue; } if (!cgraph_default_inline_p (edge->callee, &edge->inline_failed) && !better_inline_comdat_function_p (edge->callee)) { if (!cgraph_recursive_inlining_p (edge->caller, edge->callee, &edge->inline_failed)) { if (dump_file) fprintf (dump_file, " inline_failed:%s.\n", cgraph_inline_failed_string (edge->inline_failed)); } continue; } if (!tree_can_inline_p (edge) || edge->call_stmt_cannot_inline_p) { if (dump_file) fprintf (dump_file, " inline_failed:%s.\n", cgraph_inline_failed_string (edge->inline_failed)); continue; } if (cgraph_recursive_inlining_p (edge->caller, edge->callee, &edge->inline_failed)) { where = edge->caller; if (where->global.inlined_to) where = where->global.inlined_to; if (!cgraph_decide_recursive_inlining (where, flag_indirect_inlining ? &new_indirect_edges : NULL)) continue; if (flag_indirect_inlining) add_new_edges_to_heap (heap, new_indirect_edges); update_all_callee_keys (heap, where, updated_nodes); } else { struct cgraph_node *callee; if (!cgraph_check_inline_limits (edge->caller, edge->callee, &edge->inline_failed)) { if (dump_file) fprintf (dump_file, " Not inlining into %s:%s.\n", cgraph_node_name (edge->caller), cgraph_inline_failed_string (edge->inline_failed)); continue; } if (!dbg_cnt (inl)) continue; callee = edge->callee; gcc_checking_assert (!callee->global.inlined_to); cgraph_mark_inline_edge (edge, true, &new_indirect_edges); if (flag_indirect_inlining) add_new_edges_to_heap (heap, new_indirect_edges); /* We inlined last offline copy to the body. This might lead to callees of function having fewer call sites and thus they may need updating. */ if (callee->global.inlined_to) update_all_callee_keys (heap, callee, updated_nodes); else update_callee_keys (heap, edge->callee, updated_nodes); } where = edge->caller; if (where->global.inlined_to) where = where->global.inlined_to; /* Our profitability metric can depend on local properties such as number of inlinable calls and size of the function body. After inlining these properties might change for the function we inlined into (since it's body size changed) and for the functions called by function we inlined (since number of it inlinable callers might change). */ update_caller_keys (heap, where, updated_nodes); /* We removed one call of the function we just inlined. If offline copy is still needed, be sure to update the keys. */ if (callee != where && !callee->global.inlined_to) update_caller_keys (heap, callee, updated_nodes); bitmap_clear (updated_nodes); if (dump_file) { fprintf (dump_file, "INFO: %s Inlined into %s which now has time %i and size %i," "net change of %+i.\n", cgraph_node_name (edge->callee), cgraph_node_name (edge->caller), edge->caller->global.time, edge->caller->global.size, overall_size - old_size); } if (min_size > overall_size) { min_size = overall_size; max_size = compute_max_insns (min_size); if (dump_file) fprintf (dump_file, "New minimal size reached: %i\n", min_size); } } while (!fibheap_empty (heap)) { int badness = fibheap_min_key (heap); edge = (struct cgraph_edge *) fibheap_extract_min (heap); gcc_assert (edge->aux); edge->aux = NULL; if (!edge->inline_failed) continue; #ifdef ENABLE_CHECKING gcc_assert (cgraph_edge_badness (edge, false) >= badness); #endif if (dump_file) { fprintf (dump_file, "\nSkipping %s with %i size\n", cgraph_node_name (edge->callee), edge->callee->global.size); fprintf (dump_file, " called by %s in %s:%i\n" " Estimated growth after inlined into all callees is %+i insns.\n" " Estimated badness is %i, frequency %.2f.\n", cgraph_node_name (edge->caller), flag_wpa ? "unknown" : gimple_filename ((const_gimple) edge->call_stmt), flag_wpa ? -1 : gimple_lineno ((const_gimple) edge->call_stmt), cgraph_estimate_growth (edge->callee), badness, edge->frequency / (double)CGRAPH_FREQ_BASE); if (edge->count) fprintf (dump_file," Called "HOST_WIDEST_INT_PRINT_DEC"x\n", edge->count); if (dump_flags & TDF_DETAILS) cgraph_edge_badness (edge, true); } if (!edge->callee->local.disregard_inline_limits && edge->inline_failed && !cgraph_recursive_inlining_p (edge->caller, edge->callee, &edge->inline_failed)) edge->inline_failed = CIF_INLINE_UNIT_GROWTH_LIMIT; } if (new_indirect_edges) VEC_free (cgraph_edge_p, heap, new_indirect_edges); fibheap_delete (heap); BITMAP_FREE (updated_nodes); } /* Flatten NODE from the IPA inliner. */ static void cgraph_flatten (struct cgraph_node *node) { struct cgraph_edge *e; /* We shouldn't be called recursively when we are being processed. */ gcc_assert (node->aux == NULL); node->aux = (void *)(size_t) INLINE_ALL; for (e = node->callees; e; e = e->next_callee) { struct cgraph_node *orig_callee; if (e->call_stmt_cannot_inline_p) { if (dump_file) fprintf (dump_file, "Not inlining: %s", cgraph_inline_failed_string (e->inline_failed)); continue; } if (!e->callee->analyzed) { if (dump_file) fprintf (dump_file, "Not inlining: Function body not available.\n"); continue; } if (!e->callee->local.inlinable) continue; /* We've hit cycle? It is time to give up. */ if (e->callee->aux) { if (dump_file) fprintf (dump_file, "Not inlining %s into %s to avoid cycle.\n", cgraph_node_name (e->callee), cgraph_node_name (e->caller)); e->inline_failed = CIF_RECURSIVE_INLINING; continue; } /* When the edge is already inlined, we just need to recurse into it in order to fully flatten the leaves. */ if (!e->inline_failed) { cgraph_flatten (e->callee); continue; } if (cgraph_recursive_inlining_p (node, e->callee, &e->inline_failed)) { if (dump_file) fprintf (dump_file, "Not inlining: recursive call.\n"); continue; } if (!tree_can_inline_p (e)) { if (dump_file) fprintf (dump_file, "Not inlining: %s", cgraph_inline_failed_string (e->inline_failed)); continue; } if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl)) != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->callee->decl))) { if (dump_file) fprintf (dump_file, "Not inlining: SSA form does not match.\n"); continue; } /* Inline the edge and flatten the inline clone. Avoid recursing through the original node if the node was cloned. */ if (dump_file) fprintf (dump_file, " Inlining %s into %s.\n", cgraph_node_name (e->callee), cgraph_node_name (e->caller)); orig_callee = e->callee; cgraph_mark_inline_edge (e, true, NULL); if (e->callee != orig_callee) orig_callee->aux = (void *)(size_t) INLINE_ALL; cgraph_flatten (e->callee); if (e->callee != orig_callee) orig_callee->aux = NULL; } node->aux = NULL; } /* Decide on the inlining. We do so in the topological order to avoid expenses on updating data structures. */ static unsigned int cgraph_decide_inlining (void) { struct cgraph_node *node; int nnodes; struct cgraph_node **order = XCNEWVEC (struct cgraph_node *, cgraph_n_nodes); int old_size = 0; int i; int initial_size = 0; cgraph_remove_function_insertion_hook (function_insertion_hook_holder); if (in_lto_p && flag_indirect_inlining) ipa_update_after_lto_read (); if (flag_indirect_inlining) ipa_create_all_structures_for_iinln (); max_count = 0; max_benefit = 0; for (node = cgraph_nodes; node; node = node->next) if (node->analyzed) { struct cgraph_edge *e; gcc_assert (inline_summary (node)->self_size == node->global.size); if (!DECL_EXTERNAL (node->decl)) initial_size += node->global.size; for (e = node->callees; e; e = e->next_callee) if (max_count < e->count) max_count = e->count; if (max_benefit < inline_summary (node)->time_inlining_benefit) max_benefit = inline_summary (node)->time_inlining_benefit; } gcc_assert (in_lto_p || !max_count || (profile_info && flag_branch_probabilities)); overall_size = initial_size; nnodes = cgraph_postorder (order); if (dump_file) fprintf (dump_file, "\nDeciding on inlining. Starting with size %i.\n", initial_size); for (node = cgraph_nodes; node; node = node->next) node->aux = 0; if (dump_file) fprintf (dump_file, "\nFlattening functions:\n"); /* In the first pass handle functions to be flattened. Do this with a priority so none of our later choices will make this impossible. */ for (i = nnodes - 1; i >= 0; i--) { node = order[i]; /* Handle nodes to be flattened, but don't update overall unit size. Calling the incremental inliner here is lame, a simple worklist should be enough. What should be left here from the early inliner (if it runs) is cyclic cases. Ideally when processing callees we stop inlining at the entry of cycles, possibly cloning that entry point and try to flatten itself turning it into a self-recursive function. */ if (lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) != NULL) { if (dump_file) fprintf (dump_file, "Flattening %s\n", cgraph_node_name (node)); cgraph_flatten (node); } } cgraph_decide_inlining_of_small_functions (); if (flag_inline_functions_called_once) { if (dump_file) fprintf (dump_file, "\nDeciding on functions called once:\n"); /* And finally decide what functions are called once. */ for (i = nnodes - 1; i >= 0; i--) { node = order[i]; if (node->callers && !node->callers->next_caller && !node->global.inlined_to && cgraph_will_be_removed_from_program_if_no_direct_calls (node) && node->local.inlinable && cgraph_function_body_availability (node) >= AVAIL_AVAILABLE && node->callers->inline_failed && node->callers->caller != node && node->callers->caller->global.inlined_to != node && !node->callers->call_stmt_cannot_inline_p && tree_can_inline_p (node->callers) && !DECL_EXTERNAL (node->decl)) { cgraph_inline_failed_t reason; old_size = overall_size; if (dump_file) { fprintf (dump_file, "\nConsidering %s size %i.\n", cgraph_node_name (node), node->global.size); fprintf (dump_file, " Called once from %s %i insns.\n", cgraph_node_name (node->callers->caller), node->callers->caller->global.size); } if (cgraph_check_inline_limits (node->callers->caller, node, &reason)) { struct cgraph_node *caller = node->callers->caller; cgraph_mark_inline_edge (node->callers, true, NULL); if (dump_file) fprintf (dump_file, "INFO: Inlined into %s which now has %i size" " for a net change of %+i size.\n", cgraph_node_name (caller), caller->global.size, overall_size - old_size); } else { if (dump_file) fprintf (dump_file, " Not inlining: %s.\n", cgraph_inline_failed_string (reason)); } } } } /* Free ipa-prop structures if they are no longer needed. */ if (flag_indirect_inlining) ipa_free_all_structures_after_iinln (); if (dump_file) fprintf (dump_file, "\nInlined %i calls, eliminated %i functions, " "size %i turned to %i size.\n\n", ncalls_inlined, nfunctions_inlined, initial_size, overall_size); free (order); return 0; } /* Return true when N is leaf function. Accept cheap builtins in leaf functions. */ static bool leaf_node_p (struct cgraph_node *n) { struct cgraph_edge *e; /* The following is buggy -- indirect call is not considered. */ for (e = n->callees; e; e = e->next_callee) if (e->call_stmt /* Only exisit in profile use pass in LIPO */ && !is_inexpensive_builtin (e->callee->decl)) return false; return true; } /* Decide on the inlining. We do so in the topological order to avoid expenses on updating data structures. */ static bool cgraph_decide_inlining_incrementally (struct cgraph_node *node, enum inlining_mode mode) { struct cgraph_edge *e; bool inlined = false; cgraph_inline_failed_t failed_reason; #ifdef ENABLE_CHECKING verify_cgraph_node (node); #endif if (mode != INLINE_ALWAYS_INLINE && mode != INLINE_SIZE_NORECURSIVE && lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) != NULL) { if (dump_file) fprintf (dump_file, "Incrementally flattening %s\n", cgraph_node_name (node)); mode = INLINE_ALL; } /* First of all look for always inline functions. */ if (mode != INLINE_SIZE_NORECURSIVE) for (e = node->callees; e; e = e->next_callee) { if (!e->callee->local.disregard_inline_limits && (mode != INLINE_ALL || !e->callee->local.inlinable)) continue; if (dump_file) fprintf (dump_file, "Considering to always inline inline candidate %s.\n", cgraph_node_name (e->callee)); if (cgraph_recursive_inlining_p (node, e->callee, &e->inline_failed)) { if (dump_file) fprintf (dump_file, "Not inlining: recursive call.\n"); continue; } if (!tree_can_inline_p (e) || e->call_stmt_cannot_inline_p) { if (dump_file) fprintf (dump_file, "Not inlining: %s", cgraph_inline_failed_string (e->inline_failed)); continue; } if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl)) != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->callee->decl))) { if (dump_file) fprintf (dump_file, "Not inlining: SSA form does not match.\n"); continue; } if (!e->callee->analyzed) { if (dump_file) fprintf (dump_file, "Not inlining: Function body no longer available.\n"); continue; } if (dump_file) fprintf (dump_file, " Inlining %s into %s.\n", cgraph_node_name (e->callee), cgraph_node_name (e->caller)); cgraph_mark_inline_edge (e, true, NULL); inlined = true; } /* Now do the automatic inlining. */ if (mode != INLINE_ALL && mode != INLINE_ALWAYS_INLINE /* Never inline regular functions into always-inline functions during incremental inlining. */ && !node->local.disregard_inline_limits) { for (e = node->callees; e; e = e->next_callee) { int allowed_growth = 0; if (!e->callee->local.inlinable || !e->inline_failed || e->callee->local.disregard_inline_limits) continue; if (dump_file) fprintf (dump_file, "Considering inline candidate %s.\n", cgraph_node_name (e->callee)); if (cgraph_recursive_inlining_p (node, e->callee, &e->inline_failed)) { if (dump_file) fprintf (dump_file, "Not inlining: recursive call.\n"); continue; } if (gimple_in_ssa_p (DECL_STRUCT_FUNCTION (node->decl)) != gimple_in_ssa_p (DECL_STRUCT_FUNCTION (e->callee->decl))) { if (dump_file) fprintf (dump_file, "Not inlining: SSA form does not match.\n"); continue; } if (cgraph_maybe_hot_edge_p (e) && leaf_node_p (e->callee) && optimize_function_for_speed_p (cfun)) allowed_growth = PARAM_VALUE (PARAM_EARLY_INLINING_INSNS); /* When the function body would grow and inlining the function won't eliminate the need for offline copy of the function, don't inline. */ if (((mode == INLINE_SIZE || mode == INLINE_SIZE_NORECURSIVE) || (!flag_inline_functions && !DECL_DECLARED_INLINE_P (e->callee->decl))) && (cgraph_estimate_size_after_inlining (e->caller, e->callee) > e->caller->global.size + allowed_growth) && (cgraph_estimate_growth (e->callee) > allowed_growth)) { if (dump_file) fprintf (dump_file, "Not inlining: code size would grow by %i.\n", cgraph_estimate_size_after_inlining (e->caller, e->callee) - e->caller->global.size); continue; } if (e->call_stmt_cannot_inline_p || !tree_can_inline_p (e)) { if (dump_file) fprintf (dump_file, "Not inlining: call site not inlinable.\n"); continue; } if (!e->callee->analyzed) { if (dump_file) fprintf (dump_file, "Not inlining: Function body no longer available.\n"); continue; } if (!cgraph_check_inline_limits (node, e->callee, &e->inline_failed)) { if (dump_file) fprintf (dump_file, "Not inlining: %s.\n", cgraph_inline_failed_string (e->inline_failed)); continue; } if (cgraph_default_inline_p (e->callee, &failed_reason)) { if (dump_file) fprintf (dump_file, " Inlining %s into %s.\n", cgraph_node_name (e->callee), cgraph_node_name (e->caller)); cgraph_mark_inline_edge (e, true, NULL); inlined = true; } } } return inlined; } /* Because inlining might remove no-longer reachable nodes, we need to keep the array visible to garbage collector to avoid reading collected out nodes. */ static int nnodes; static GTY ((length ("nnodes"))) struct cgraph_node **order; /* Do inlining of small functions. Doing so early helps profiling and other passes to be somewhat more effective and avoids some code duplication in later real inlining pass for testcases with very many function calls. */ static unsigned int cgraph_early_inlining (void) { struct cgraph_node *node = cgraph_node (current_function_decl); unsigned int todo = 0; int iterations = 0; if (seen_error ()) return 0; if (!optimize || flag_no_inline || !flag_early_inlining) { /* When not optimizing or not inlining inline only always-inline functions. */ cgraph_decide_inlining_incrementally (node, INLINE_ALWAYS_INLINE); timevar_push (TV_INTEGRATION); todo |= optimize_inline_calls (current_function_decl); timevar_pop (TV_INTEGRATION); } else { if (lookup_attribute ("flatten", DECL_ATTRIBUTES (node->decl)) != NULL) { if (dump_file) fprintf (dump_file, "Flattening %s\n", cgraph_node_name (node)); cgraph_flatten (node); timevar_push (TV_INTEGRATION); todo |= optimize_inline_calls (current_function_decl); timevar_pop (TV_INTEGRATION); } /* We iterate incremental inlining to get trivial cases of indirect inlining. */ while (iterations < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS) && cgraph_decide_inlining_incrementally (node, iterations ? INLINE_SIZE_NORECURSIVE : INLINE_SIZE)) { timevar_push (TV_INTEGRATION); todo |= optimize_inline_calls (current_function_decl); iterations++; timevar_pop (TV_INTEGRATION); } if (dump_file) fprintf (dump_file, "Iterations: %i\n", iterations); } cfun->always_inline_functions_inlined = true; return todo; } struct gimple_opt_pass pass_early_inline = { { GIMPLE_PASS, "einline", /* name */ NULL, /* gate */ cgraph_early_inlining, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_INLINE_HEURISTICS, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ TODO_dump_func /* todo_flags_finish */ } }; /* See if statement might disappear after inlining. 0 - means not eliminated 1 - half of statements goes away 2 - for sure it is eliminated. We are not terribly sophisticated, basically looking for simple abstraction penalty wrappers. */ static int eliminated_by_inlining_prob (gimple stmt) { enum gimple_code code = gimple_code (stmt); switch (code) { case GIMPLE_RETURN: return 2; case GIMPLE_ASSIGN: if (gimple_num_ops (stmt) != 2) return 0; /* Casts of parameters, loads from parameters passed by reference and stores to return value or parameters are often free after inlining dua to SRA and further combining. Assume that half of statements goes away. */ if (gimple_assign_rhs_code (stmt) == CONVERT_EXPR || gimple_assign_rhs_code (stmt) == NOP_EXPR || gimple_assign_rhs_code (stmt) == VIEW_CONVERT_EXPR || gimple_assign_rhs_class (stmt) == GIMPLE_SINGLE_RHS) { tree rhs = gimple_assign_rhs1 (stmt); tree lhs = gimple_assign_lhs (stmt); tree inner_rhs = rhs; tree inner_lhs = lhs; bool rhs_free = false; bool lhs_free = false; while (handled_component_p (inner_lhs) || TREE_CODE (inner_lhs) == MEM_REF) inner_lhs = TREE_OPERAND (inner_lhs, 0); while (handled_component_p (inner_rhs) || TREE_CODE (inner_rhs) == ADDR_EXPR || TREE_CODE (inner_rhs) == MEM_REF) inner_rhs = TREE_OPERAND (inner_rhs, 0); if (TREE_CODE (inner_rhs) == PARM_DECL || (TREE_CODE (inner_rhs) == SSA_NAME && SSA_NAME_IS_DEFAULT_DEF (inner_rhs) && TREE_CODE (SSA_NAME_VAR (inner_rhs)) == PARM_DECL)) rhs_free = true; if (rhs_free && is_gimple_reg (lhs)) lhs_free = true; if (((TREE_CODE (inner_lhs) == PARM_DECL || (TREE_CODE (inner_lhs) == SSA_NAME && SSA_NAME_IS_DEFAULT_DEF (inner_lhs) && TREE_CODE (SSA_NAME_VAR (inner_lhs)) == PARM_DECL)) && inner_lhs != lhs) || TREE_CODE (inner_lhs) == RESULT_DECL || (TREE_CODE (inner_lhs) == SSA_NAME && TREE_CODE (SSA_NAME_VAR (inner_lhs)) == RESULT_DECL)) lhs_free = true; if (lhs_free && (is_gimple_reg (rhs) || is_gimple_min_invariant (rhs))) rhs_free = true; if (lhs_free && rhs_free) return 1; } return 0; default: return 0; } } /* Compute function body size parameters for NODE. */ static void estimate_function_body_sizes (struct cgraph_node *node) { gcov_type time = 0; gcov_type time_inlining_benefit = 0; /* Estimate static overhead for function prologue/epilogue and alignment. */ int size = PARAM_VALUE (PARAM_INLINE_FUNCTION_OVERHEAD_SIZE); /* Benefits are scaled by probability of elimination that is in range <0,2>. */ int size_inlining_benefit = PARAM_VALUE (PARAM_INLINE_FUNCTION_OVERHEAD_SIZE) * 2; basic_block bb; gimple_stmt_iterator bsi; struct function *my_function = DECL_STRUCT_FUNCTION (node->decl); tree arg; int freq; tree funtype = TREE_TYPE (node->decl); if (dump_file) fprintf (dump_file, "Analyzing function body size: %s\n", cgraph_node_name (node)); gcc_assert (my_function && my_function->cfg); FOR_EACH_BB_FN (bb, my_function) { freq = compute_call_stmt_bb_frequency (node->decl, bb); for (bsi = gsi_start_bb (bb); !gsi_end_p (bsi); gsi_next (&bsi)) { gimple stmt = gsi_stmt (bsi); int this_size = estimate_num_insns (stmt, &eni_size_weights); int this_time = estimate_num_insns (stmt, &eni_time_weights); int prob; if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, " freq:%6i size:%3i time:%3i ", freq, this_size, this_time); print_gimple_stmt (dump_file, stmt, 0, 0); } if (!dbg_cnt (inl)) continue; if (dump_file) { fprintf (dump_file, " freq:%6i size:%3i time:%3i ", freq, this_size, this_time); print_gimple_stmt (dump_file, gsi_stmt (bsi), 0, 0); } this_time *= freq; time += this_time; size += this_size; prob = eliminated_by_inlining_prob (stmt); if (prob == 1 && dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, " 50%% will be eliminated by inlining\n"); if (prob == 2 && dump_file && (dump_flags & TDF_DETAILS)) fprintf (dump_file, " will eliminated by inlining\n"); size_inlining_benefit += this_size * prob; time_inlining_benefit += this_time * prob; gcc_assert (time >= 0); gcc_assert (size >= 0); } } time = (time + CGRAPH_FREQ_BASE / 2) / CGRAPH_FREQ_BASE; time_inlining_benefit = ((time_inlining_benefit + CGRAPH_FREQ_BASE) / (CGRAPH_FREQ_BASE * 2)); size_inlining_benefit = (size_inlining_benefit + 1) / 2; if (dump_file) fprintf (dump_file, "Overall function body time: %i-%i size: %i-%i\n", (int)time, (int)time_inlining_benefit, size, size_inlining_benefit); time_inlining_benefit += eni_time_weights.call_cost; size_inlining_benefit += eni_size_weights.call_cost; if (!VOID_TYPE_P (TREE_TYPE (funtype))) { int cost = estimate_move_cost (TREE_TYPE (funtype)); time_inlining_benefit += cost; size_inlining_benefit += cost; } for (arg = DECL_ARGUMENTS (node->decl); arg; arg = DECL_CHAIN (arg)) if (!VOID_TYPE_P (TREE_TYPE (arg))) { int cost = estimate_move_cost (TREE_TYPE (arg)); time_inlining_benefit += cost; size_inlining_benefit += cost; } if (time_inlining_benefit > MAX_TIME) time_inlining_benefit = MAX_TIME; if (time > MAX_TIME) time = MAX_TIME; inline_summary (node)->self_time = time; inline_summary (node)->self_size = size; if (dump_file) fprintf (dump_file, "With function call overhead time: %i-%i size: %i-%i\n", (int)time, (int)time_inlining_benefit, size, size_inlining_benefit); inline_summary (node)->time_inlining_benefit = time_inlining_benefit; inline_summary (node)->size_inlining_benefit = size_inlining_benefit; } /* Compute parameters of functions used by inliner. */ void compute_inline_parameters (struct cgraph_node *node) { HOST_WIDE_INT self_stack_size; gcc_assert (!node->global.inlined_to); /* Estimate the stack size for the function if we're optimizing. */ self_stack_size = optimize ? estimated_stack_frame_size (node) : 0; inline_summary (node)->estimated_self_stack_size = self_stack_size; node->global.estimated_stack_size = self_stack_size; /* Can this function be inlined at all? */ node->local.inlinable = tree_inlinable_function_p (node->decl); if (!node->local.inlinable) node->local.disregard_inline_limits = 0; /* Inlinable functions always can change signature. */ if (node->local.inlinable) node->local.can_change_signature = true; else { struct cgraph_edge *e; /* Functions calling builtin_apply can not change signature. */ for (e = node->callees; e; e = e->next_callee) if (DECL_BUILT_IN (e->callee->decl) && DECL_BUILT_IN_CLASS (e->callee->decl) == BUILT_IN_NORMAL && DECL_FUNCTION_CODE (e->callee->decl) == BUILT_IN_APPLY_ARGS) break; node->local.can_change_signature = !e; } estimate_function_body_sizes (node); /* Inlining characteristics are maintained by the cgraph_mark_inline. */ node->global.time = inline_summary (node)->self_time; node->global.size = inline_summary (node)->self_size; } /* Compute parameters of functions used by inliner using current_function_decl. */ static unsigned int compute_inline_parameters_for_current (void) { compute_inline_parameters (cgraph_node (current_function_decl)); return 0; } struct gimple_opt_pass pass_inline_parameters = { { GIMPLE_PASS, "inline_param", /* name */ NULL, /* gate */ compute_inline_parameters_for_current,/* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_INLINE_HEURISTICS, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ 0 /* todo_flags_finish */ } }; /* This function performs intraprocedural analysis in NODE that is required to inline indirect calls. */ static void inline_indirect_intraprocedural_analysis (struct cgraph_node *node) { ipa_analyze_node (node); if (dump_file && (dump_flags & TDF_DETAILS)) { ipa_print_node_params (dump_file, node); ipa_print_node_jump_functions (dump_file, node); } } /* Note function body size. */ static void analyze_function (struct cgraph_node *node) { push_cfun (DECL_STRUCT_FUNCTION (node->decl)); current_function_decl = node->decl; compute_inline_parameters (node); /* FIXME: We should remove the optimize check after we ensure we never run IPA passes when not optimizing. */ if (flag_indirect_inlining && optimize) inline_indirect_intraprocedural_analysis (node); current_function_decl = NULL; pop_cfun (); } /* Called when new function is inserted to callgraph late. */ static void add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED) { analyze_function (node); } /* Note function body size. */ static void inline_generate_summary (void) { struct cgraph_node *node; function_insertion_hook_holder = cgraph_add_function_insertion_hook (&add_new_function, NULL); if (flag_indirect_inlining) ipa_register_cgraph_hooks (); for (node = cgraph_nodes; node; node = node->next) if (node->analyzed) analyze_function (node); return; } /* Apply inline plan to function. */ static unsigned int inline_transform (struct cgraph_node *node) { unsigned int todo = 0; struct cgraph_edge *e; bool inline_p = false; /* FIXME: Currently the pass manager is adding inline transform more than once to some clones. This needs revisiting after WPA cleanups. */ if (cfun->after_inlining) return 0; /* We might need the body of this function so that we can expand it inline somewhere else. */ if (cgraph_preserve_function_body_p (node->decl)) save_inline_function_body (node); for (e = node->callees; e; e = e->next_callee) { cgraph_redirect_edge_call_stmt_to_callee (e); if (!e->inline_failed || warn_inline) inline_p = true; } if (inline_p) { timevar_push (TV_INTEGRATION); todo = optimize_inline_calls (current_function_decl); timevar_pop (TV_INTEGRATION); } cfun->always_inline_functions_inlined = true; cfun->after_inlining = true; return todo | execute_fixup_cfg (); } /* Read inline summary. Jump functions are shared among ipa-cp and inliner, so when ipa-cp is active, we don't need to write them twice. */ static void inline_read_summary (void) { if (flag_indirect_inlining) { ipa_register_cgraph_hooks (); if (!flag_ipa_cp) ipa_prop_read_jump_functions (); } function_insertion_hook_holder = cgraph_add_function_insertion_hook (&add_new_function, NULL); } /* Write inline summary for node in SET. Jump functions are shared among ipa-cp and inliner, so when ipa-cp is active, we don't need to write them twice. */ static void inline_write_summary (cgraph_node_set set, varpool_node_set vset ATTRIBUTE_UNUSED) { if (flag_indirect_inlining && !flag_ipa_cp) ipa_prop_write_jump_functions (set); } /* When to run IPA inlining. Inlining of always-inline functions happens during early inlining. */ static bool gate_cgraph_decide_inlining (void) { /* ??? We'd like to skip this if not optimizing or not inlining as all always-inline functions have been processed by early inlining already. But this at least breaks EH with C++ as we need to unconditionally run fixup_cfg even at -O0. So leave it on unconditionally for now. */ return 1; } struct ipa_opt_pass_d pass_ipa_inline = { { IPA_PASS, "inline", /* name */ gate_cgraph_decide_inlining, /* gate */ cgraph_decide_inlining, /* execute */ NULL, /* sub */ NULL, /* next */ 0, /* static_pass_number */ TV_INLINE_HEURISTICS, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ TODO_remove_functions, /* todo_flags_finish */ TODO_dump_cgraph | TODO_dump_func | TODO_remove_functions | TODO_ggc_collect /* todo_flags_finish */ }, inline_generate_summary, /* generate_summary */ inline_write_summary, /* write_summary */ inline_read_summary, /* read_summary */ NULL, /* write_optimization_summary */ NULL, /* read_optimization_summary */ NULL, /* stmt_fixup */ 0, /* TODOs */ inline_transform, /* function_transform */ NULL, /* variable_transform */ }; #include "gt-ipa-inline.h"