/* Read and annotate call graph profile from the auto profile data file. Copyright (C) 2014-2017 Free Software Foundation, Inc. Contributed by Dehao Chen (dehao@google.com) 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" #define INCLUDE_MAP #define INCLUDE_SET #include "system.h" #include "coretypes.h" #include "backend.h" #include "tree.h" #include "gimple.h" #include "predict.h" #include "alloc-pool.h" #include "tree-pass.h" #include "ssa.h" #include "cgraph.h" #include "gcov-io.h" #include "diagnostic-core.h" #include "profile.h" #include "langhooks.h" #include "cfgloop.h" #include "tree-cfg.h" #include "tree-cfgcleanup.h" #include "tree-into-ssa.h" #include "gimple-iterator.h" #include "value-prof.h" #include "params.h" #include "symbol-summary.h" #include "ipa-prop.h" #include "ipa-fnsummary.h" #include "ipa-inline.h" #include "tree-inline.h" #include "auto-profile.h" #include "tree-pretty-print.h" #include "gimple-pretty-print.h" /* The following routines implements AutoFDO optimization. This optimization uses sampling profiles to annotate basic block counts and uses heuristics to estimate branch probabilities. There are three phases in AutoFDO: Phase 1: Read profile from the profile data file. The following info is read from the profile datafile: * string_table: a map between function name and its index. * autofdo_source_profile: a map from function_instance name to function_instance. This is represented as a forest of function_instances. * WorkingSet: a histogram of how many instructions are covered for a given percentage of total cycles. This is describing the binary level information (not source level). This info is used to help decide if we want aggressive optimizations that could increase code footprint (e.g. loop unroll etc.) A function instance is an instance of function that could either be a standalone symbol, or a clone of a function that is inlined into another function. Phase 2: Early inline + value profile transformation. Early inline uses autofdo_source_profile to find if a callsite is: * inlined in the profiled binary. * callee body is hot in the profiling run. If both condition satisfies, early inline will inline the callsite regardless of the code growth. Phase 2 is an iterative process. During each iteration, we also check if an indirect callsite is promoted and inlined in the profiling run. If yes, vpt will happen to force promote it and in the next iteration, einline will inline the promoted callsite in the next iteration. Phase 3: Annotate control flow graph. AutoFDO uses a separate pass to: * Annotate basic block count * Estimate branch probability After the above 3 phases, all profile is readily annotated on the GCC IR. AutoFDO tries to reuse all FDO infrastructure as much as possible to make use of the profile. E.g. it uses existing mechanism to calculate the basic block/edge frequency, as well as the cgraph node/edge count. */ #define DEFAULT_AUTO_PROFILE_FILE "fbdata.afdo" #define AUTO_PROFILE_VERSION 1 namespace autofdo { /* Represent a source location: (function_decl, lineno). */ typedef std::pair decl_lineno; /* Represent an inline stack. vector[0] is the leaf node. */ typedef auto_vec inline_stack; /* String array that stores function names. */ typedef auto_vec string_vector; /* Map from function name's index in string_table to target's execution count. */ typedef std::map icall_target_map; /* Set of gimple stmts. Used to track if the stmt has already been promoted to direct call. */ typedef std::set stmt_set; /* Represent count info of an inline stack. */ struct count_info { /* Sampled count of the inline stack. */ gcov_type count; /* Map from indirect call target to its sample count. */ icall_target_map targets; /* Whether this inline stack is already used in annotation. Each inline stack should only be used to annotate IR once. This will be enforced when instruction-level discriminator is supported. */ bool annotated; }; /* operator< for "const char *". */ struct string_compare { bool operator()(const char *a, const char *b) const { return strcmp (a, b) < 0; } }; /* Store a string array, indexed by string position in the array. */ class string_table { public: string_table () {} ~string_table (); /* For a given string, returns its index. */ int get_index (const char *name) const; /* For a given decl, returns the index of the decl name. */ int get_index_by_decl (tree decl) const; /* For a given index, returns the string. */ const char *get_name (int index) const; /* Read profile, return TRUE on success. */ bool read (); private: typedef std::map string_index_map; string_vector vector_; string_index_map map_; }; /* Profile of a function instance: 1. total_count of the function. 2. head_count (entry basic block count) of the function (only valid when function is a top-level function_instance, i.e. it is the original copy instead of the inlined copy). 3. map from source location (decl_lineno) to profile (count_info). 4. map from callsite to callee function_instance. */ class function_instance { public: typedef auto_vec function_instance_stack; /* Read the profile and return a function_instance with head count as HEAD_COUNT. Recursively read callsites to create nested function_instances too. STACK is used to track the recursive creation process. */ static function_instance * read_function_instance (function_instance_stack *stack, gcov_type head_count); /* Recursively deallocate all callsites (nested function_instances). */ ~function_instance (); /* Accessors. */ int name () const { return name_; } gcov_type total_count () const { return total_count_; } gcov_type head_count () const { return head_count_; } /* Traverse callsites of the current function_instance to find one at the location of LINENO and callee name represented in DECL. */ function_instance *get_function_instance_by_decl (unsigned lineno, tree decl) const; /* Store the profile info for LOC in INFO. Return TRUE if profile info is found. */ bool get_count_info (location_t loc, count_info *info) const; /* Read the inlined indirect call target profile for STMT and store it in MAP, return the total count for all inlined indirect calls. */ gcov_type find_icall_target_map (gcall *stmt, icall_target_map *map) const; /* Sum of counts that is used during annotation. */ gcov_type total_annotated_count () const; /* Mark LOC as annotated. */ void mark_annotated (location_t loc); private: /* Callsite, represented as (decl_lineno, callee_function_name_index). */ typedef std::pair callsite; /* Map from callsite to callee function_instance. */ typedef std::map callsite_map; function_instance (unsigned name, gcov_type head_count) : name_ (name), total_count_ (0), head_count_ (head_count) { } /* Map from source location (decl_lineno) to profile (count_info). */ typedef std::map position_count_map; /* function_instance name index in the string_table. */ unsigned name_; /* Total sample count. */ gcov_type total_count_; /* Entry BB's sample count. */ gcov_type head_count_; /* Map from callsite location to callee function_instance. */ callsite_map callsites; /* Map from source location to count_info. */ position_count_map pos_counts; }; /* Profile for all functions. */ class autofdo_source_profile { public: static autofdo_source_profile * create () { autofdo_source_profile *map = new autofdo_source_profile (); if (map->read ()) return map; delete map; return NULL; } ~autofdo_source_profile (); /* For a given DECL, returns the top-level function_instance. */ function_instance *get_function_instance_by_decl (tree decl) const; /* Find count_info for a given gimple STMT. If found, store the count_info in INFO and return true; otherwise return false. */ bool get_count_info (gimple *stmt, count_info *info) const; /* Find total count of the callee of EDGE. */ gcov_type get_callsite_total_count (struct cgraph_edge *edge) const; /* Update value profile INFO for STMT from the inlined indirect callsite. Return true if INFO is updated. */ bool update_inlined_ind_target (gcall *stmt, count_info *info); /* Mark LOC as annotated. */ void mark_annotated (location_t loc); private: /* Map from function_instance name index (in string_table) to function_instance. */ typedef std::map name_function_instance_map; autofdo_source_profile () {} /* Read AutoFDO profile and returns TRUE on success. */ bool read (); /* Return the function_instance in the profile that correspond to the inline STACK. */ function_instance * get_function_instance_by_inline_stack (const inline_stack &stack) const; name_function_instance_map map_; }; /* Store the strings read from the profile data file. */ static string_table *afdo_string_table; /* Store the AutoFDO source profile. */ static autofdo_source_profile *afdo_source_profile; /* gcov_ctr_summary structure to store the profile_info. */ static struct gcov_ctr_summary *afdo_profile_info; /* Helper functions. */ /* Return the original name of NAME: strip the suffix that starts with '.' Caller is responsible for freeing RET. */ static char * get_original_name (const char *name) { char *ret = xstrdup (name); char *find = strchr (ret, '.'); if (find != NULL) *find = 0; return ret; } /* Return the combined location, which is a 32bit integer in which higher 16 bits stores the line offset of LOC to the start lineno of DECL, The lower 16 bits stores the discriminator. */ static unsigned get_combined_location (location_t loc, tree decl) { /* TODO: allow more bits for line and less bits for discriminator. */ if (LOCATION_LINE (loc) - DECL_SOURCE_LINE (decl) >= (1<<16)) warning_at (loc, OPT_Woverflow, "offset exceeds 16 bytes"); return ((LOCATION_LINE (loc) - DECL_SOURCE_LINE (decl)) << 16); } /* Return the function decl of a given lexical BLOCK. */ static tree get_function_decl_from_block (tree block) { tree decl; if (LOCATION_LOCUS (BLOCK_SOURCE_LOCATION (block)) == UNKNOWN_LOCATION) return NULL_TREE; for (decl = BLOCK_ABSTRACT_ORIGIN (block); decl && (TREE_CODE (decl) == BLOCK); decl = BLOCK_ABSTRACT_ORIGIN (decl)) if (TREE_CODE (decl) == FUNCTION_DECL) break; return decl; } /* Store inline stack for STMT in STACK. */ static void get_inline_stack (location_t locus, inline_stack *stack) { if (LOCATION_LOCUS (locus) == UNKNOWN_LOCATION) return; tree block = LOCATION_BLOCK (locus); if (block && TREE_CODE (block) == BLOCK) { int level = 0; for (block = BLOCK_SUPERCONTEXT (block); block && (TREE_CODE (block) == BLOCK); block = BLOCK_SUPERCONTEXT (block)) { location_t tmp_locus = BLOCK_SOURCE_LOCATION (block); if (LOCATION_LOCUS (tmp_locus) == UNKNOWN_LOCATION) continue; tree decl = get_function_decl_from_block (block); stack->safe_push ( std::make_pair (decl, get_combined_location (locus, decl))); locus = tmp_locus; level++; } } stack->safe_push ( std::make_pair (current_function_decl, get_combined_location (locus, current_function_decl))); } /* Return STMT's combined location, which is a 32bit integer in which higher 16 bits stores the line offset of LOC to the start lineno of DECL, The lower 16 bits stores the discriminator. */ static unsigned get_relative_location_for_stmt (gimple *stmt) { location_t locus = gimple_location (stmt); if (LOCATION_LOCUS (locus) == UNKNOWN_LOCATION) return UNKNOWN_LOCATION; for (tree block = gimple_block (stmt); block && (TREE_CODE (block) == BLOCK); block = BLOCK_SUPERCONTEXT (block)) if (LOCATION_LOCUS (BLOCK_SOURCE_LOCATION (block)) != UNKNOWN_LOCATION) return get_combined_location (locus, get_function_decl_from_block (block)); return get_combined_location (locus, current_function_decl); } /* Return true if BB contains indirect call. */ static bool has_indirect_call (basic_block bb) { gimple_stmt_iterator gsi; for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gimple *stmt = gsi_stmt (gsi); if (gimple_code (stmt) == GIMPLE_CALL && !gimple_call_internal_p (stmt) && (gimple_call_fn (stmt) == NULL || TREE_CODE (gimple_call_fn (stmt)) != FUNCTION_DECL)) return true; } return false; } /* Member functions for string_table. */ /* Deconstructor. */ string_table::~string_table () { for (unsigned i = 0; i < vector_.length (); i++) free (vector_[i]); } /* Return the index of a given function NAME. Return -1 if NAME is not found in string table. */ int string_table::get_index (const char *name) const { if (name == NULL) return -1; string_index_map::const_iterator iter = map_.find (name); if (iter == map_.end ()) return -1; return iter->second; } /* Return the index of a given function DECL. Return -1 if DECL is not found in string table. */ int string_table::get_index_by_decl (tree decl) const { char *name = get_original_name (IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (decl))); int ret = get_index (name); free (name); if (ret != -1) return ret; ret = get_index (lang_hooks.dwarf_name (decl, 0)); if (ret != -1) return ret; if (DECL_ABSTRACT_ORIGIN (decl)) return get_index_by_decl (DECL_ABSTRACT_ORIGIN (decl)); return -1; } /* Return the function name of a given INDEX. */ const char * string_table::get_name (int index) const { gcc_assert (index > 0 && index < (int)vector_.length ()); return vector_[index]; } /* Read the string table. Return TRUE if reading is successful. */ bool string_table::read () { if (gcov_read_unsigned () != GCOV_TAG_AFDO_FILE_NAMES) return false; /* Skip the length of the section. */ gcov_read_unsigned (); /* Read in the file name table. */ unsigned string_num = gcov_read_unsigned (); for (unsigned i = 0; i < string_num; i++) { vector_.safe_push (get_original_name (gcov_read_string ())); map_[vector_.last ()] = i; } return true; } /* Member functions for function_instance. */ function_instance::~function_instance () { for (callsite_map::iterator iter = callsites.begin (); iter != callsites.end (); ++iter) delete iter->second; } /* Traverse callsites of the current function_instance to find one at the location of LINENO and callee name represented in DECL. */ function_instance * function_instance::get_function_instance_by_decl (unsigned lineno, tree decl) const { int func_name_idx = afdo_string_table->get_index_by_decl (decl); if (func_name_idx != -1) { callsite_map::const_iterator ret = callsites.find (std::make_pair (lineno, func_name_idx)); if (ret != callsites.end ()) return ret->second; } func_name_idx = afdo_string_table->get_index (lang_hooks.dwarf_name (decl, 0)); if (func_name_idx != -1) { callsite_map::const_iterator ret = callsites.find (std::make_pair (lineno, func_name_idx)); if (ret != callsites.end ()) return ret->second; } if (DECL_ABSTRACT_ORIGIN (decl)) return get_function_instance_by_decl (lineno, DECL_ABSTRACT_ORIGIN (decl)); return NULL; } /* Store the profile info for LOC in INFO. Return TRUE if profile info is found. */ bool function_instance::get_count_info (location_t loc, count_info *info) const { position_count_map::const_iterator iter = pos_counts.find (loc); if (iter == pos_counts.end ()) return false; *info = iter->second; return true; } /* Mark LOC as annotated. */ void function_instance::mark_annotated (location_t loc) { position_count_map::iterator iter = pos_counts.find (loc); if (iter == pos_counts.end ()) return; iter->second.annotated = true; } /* Read the inlined indirect call target profile for STMT and store it in MAP, return the total count for all inlined indirect calls. */ gcov_type function_instance::find_icall_target_map (gcall *stmt, icall_target_map *map) const { gcov_type ret = 0; unsigned stmt_offset = get_relative_location_for_stmt (stmt); for (callsite_map::const_iterator iter = callsites.begin (); iter != callsites.end (); ++iter) { unsigned callee = iter->second->name (); /* Check if callsite location match the stmt. */ if (iter->first.first != stmt_offset) continue; struct cgraph_node *node = cgraph_node::get_for_asmname ( get_identifier (afdo_string_table->get_name (callee))); if (node == NULL) continue; if (!check_ic_target (stmt, node)) continue; (*map)[callee] = iter->second->total_count (); ret += iter->second->total_count (); } return ret; } /* Read the profile and create a function_instance with head count as HEAD_COUNT. Recursively read callsites to create nested function_instances too. STACK is used to track the recursive creation process. */ /* function instance profile format: ENTRY_COUNT: 8 bytes NAME_INDEX: 4 bytes NUM_POS_COUNTS: 4 bytes NUM_CALLSITES: 4 byte POS_COUNT_1: POS_1_OFFSET: 4 bytes NUM_TARGETS: 4 bytes COUNT: 8 bytes TARGET_1: VALUE_PROFILE_TYPE: 4 bytes TARGET_IDX: 8 bytes COUNT: 8 bytes TARGET_2 ... TARGET_n POS_COUNT_2 ... POS_COUNT_N CALLSITE_1: CALLSITE_1_OFFSET: 4 bytes FUNCTION_INSTANCE_PROFILE (nested) CALLSITE_2 ... CALLSITE_n. */ function_instance * function_instance::read_function_instance (function_instance_stack *stack, gcov_type head_count) { unsigned name = gcov_read_unsigned (); unsigned num_pos_counts = gcov_read_unsigned (); unsigned num_callsites = gcov_read_unsigned (); function_instance *s = new function_instance (name, head_count); stack->safe_push (s); for (unsigned i = 0; i < num_pos_counts; i++) { unsigned offset = gcov_read_unsigned () & 0xffff0000; unsigned num_targets = gcov_read_unsigned (); gcov_type count = gcov_read_counter (); s->pos_counts[offset].count = count; for (unsigned j = 0; j < stack->length (); j++) (*stack)[j]->total_count_ += count; for (unsigned j = 0; j < num_targets; j++) { /* Only indirect call target histogram is supported now. */ gcov_read_unsigned (); gcov_type target_idx = gcov_read_counter (); s->pos_counts[offset].targets[target_idx] = gcov_read_counter (); } } for (unsigned i = 0; i < num_callsites; i++) { unsigned offset = gcov_read_unsigned (); function_instance *callee_function_instance = read_function_instance (stack, 0); s->callsites[std::make_pair (offset, callee_function_instance->name ())] = callee_function_instance; } stack->pop (); return s; } /* Sum of counts that is used during annotation. */ gcov_type function_instance::total_annotated_count () const { gcov_type ret = 0; for (callsite_map::const_iterator iter = callsites.begin (); iter != callsites.end (); ++iter) ret += iter->second->total_annotated_count (); for (position_count_map::const_iterator iter = pos_counts.begin (); iter != pos_counts.end (); ++iter) if (iter->second.annotated) ret += iter->second.count; return ret; } /* Member functions for autofdo_source_profile. */ autofdo_source_profile::~autofdo_source_profile () { for (name_function_instance_map::const_iterator iter = map_.begin (); iter != map_.end (); ++iter) delete iter->second; } /* For a given DECL, returns the top-level function_instance. */ function_instance * autofdo_source_profile::get_function_instance_by_decl (tree decl) const { int index = afdo_string_table->get_index_by_decl (decl); if (index == -1) return NULL; name_function_instance_map::const_iterator ret = map_.find (index); return ret == map_.end () ? NULL : ret->second; } /* Find count_info for a given gimple STMT. If found, store the count_info in INFO and return true; otherwise return false. */ bool autofdo_source_profile::get_count_info (gimple *stmt, count_info *info) const { if (LOCATION_LOCUS (gimple_location (stmt)) == cfun->function_end_locus) return false; inline_stack stack; get_inline_stack (gimple_location (stmt), &stack); if (stack.length () == 0) return false; function_instance *s = get_function_instance_by_inline_stack (stack); if (s == NULL) return false; return s->get_count_info (stack[0].second, info); } /* Mark LOC as annotated. */ void autofdo_source_profile::mark_annotated (location_t loc) { inline_stack stack; get_inline_stack (loc, &stack); if (stack.length () == 0) return; function_instance *s = get_function_instance_by_inline_stack (stack); if (s == NULL) return; s->mark_annotated (stack[0].second); } /* Update value profile INFO for STMT from the inlined indirect callsite. Return true if INFO is updated. */ bool autofdo_source_profile::update_inlined_ind_target (gcall *stmt, count_info *info) { if (dump_file) { fprintf (dump_file, "Checking indirect call -> direct call "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); } if (LOCATION_LOCUS (gimple_location (stmt)) == cfun->function_end_locus) { if (dump_file) fprintf (dump_file, " good locus\n"); return false; } count_info old_info; get_count_info (stmt, &old_info); gcov_type total = 0; for (icall_target_map::const_iterator iter = old_info.targets.begin (); iter != old_info.targets.end (); ++iter) total += iter->second; /* Program behavior changed, original promoted (and inlined) target is not hot any more. Will avoid promote the original target. To check if original promoted target is still hot, we check the total count of the unpromoted targets (stored in old_info). If it is no less than half of the callsite count (stored in INFO), the original promoted target is considered not hot any more. */ if (total >= info->count / 2) { if (dump_file) fprintf (dump_file, " not hot anymore %ld >= %ld", (long)total, (long)info->count /2); return false; } inline_stack stack; get_inline_stack (gimple_location (stmt), &stack); if (stack.length () == 0) { if (dump_file) fprintf (dump_file, " no inline stack\n"); return false; } function_instance *s = get_function_instance_by_inline_stack (stack); if (s == NULL) { if (dump_file) fprintf (dump_file, " function not found in inline stack\n"); return false; } icall_target_map map; if (s->find_icall_target_map (stmt, &map) == 0) { if (dump_file) fprintf (dump_file, " no target map\n"); return false; } for (icall_target_map::const_iterator iter = map.begin (); iter != map.end (); ++iter) info->targets[iter->first] = iter->second; if (dump_file) fprintf (dump_file, " looks good\n"); return true; } /* Find total count of the callee of EDGE. */ gcov_type autofdo_source_profile::get_callsite_total_count ( struct cgraph_edge *edge) const { inline_stack stack; stack.safe_push (std::make_pair (edge->callee->decl, 0)); get_inline_stack (gimple_location (edge->call_stmt), &stack); function_instance *s = get_function_instance_by_inline_stack (stack); if (s == NULL || afdo_string_table->get_index (IDENTIFIER_POINTER ( DECL_ASSEMBLER_NAME (edge->callee->decl))) != s->name ()) return 0; return s->total_count (); } /* Read AutoFDO profile and returns TRUE on success. */ /* source profile format: GCOV_TAG_AFDO_FUNCTION: 4 bytes LENGTH: 4 bytes NUM_FUNCTIONS: 4 bytes FUNCTION_INSTANCE_1 FUNCTION_INSTANCE_2 ... FUNCTION_INSTANCE_N. */ bool autofdo_source_profile::read () { if (gcov_read_unsigned () != GCOV_TAG_AFDO_FUNCTION) { inform (0, "Not expected TAG."); return false; } /* Skip the length of the section. */ gcov_read_unsigned (); /* Read in the function/callsite profile, and store it in local data structure. */ unsigned function_num = gcov_read_unsigned (); for (unsigned i = 0; i < function_num; i++) { function_instance::function_instance_stack stack; function_instance *s = function_instance::read_function_instance ( &stack, gcov_read_counter ()); afdo_profile_info->sum_all += s->total_count (); map_[s->name ()] = s; } return true; } /* Return the function_instance in the profile that correspond to the inline STACK. */ function_instance * autofdo_source_profile::get_function_instance_by_inline_stack ( const inline_stack &stack) const { name_function_instance_map::const_iterator iter = map_.find ( afdo_string_table->get_index_by_decl (stack[stack.length () - 1].first)); if (iter == map_.end()) return NULL; function_instance *s = iter->second; for (unsigned i = stack.length() - 1; i > 0; i--) { s = s->get_function_instance_by_decl ( stack[i].second, stack[i - 1].first); if (s == NULL) return NULL; } return s; } /* Module profile is only used by LIPO. Here we simply ignore it. */ static void fake_read_autofdo_module_profile () { /* Read in the module info. */ gcov_read_unsigned (); /* Skip the length of the section. */ gcov_read_unsigned (); /* Read in the file name table. */ unsigned total_module_num = gcov_read_unsigned (); gcc_assert (total_module_num == 0); } /* Read data from profile data file. */ static void read_profile (void) { if (gcov_open (auto_profile_file, 1) == 0) { error ("cannot open profile file %s", auto_profile_file); return; } if (gcov_read_unsigned () != GCOV_DATA_MAGIC) { error ("AutoFDO profile magic number does not match"); return; } /* Skip the version number. */ unsigned version = gcov_read_unsigned (); if (version != AUTO_PROFILE_VERSION) { error ("AutoFDO profile version %u does match %u", version, AUTO_PROFILE_VERSION); return; } /* Skip the empty integer. */ gcov_read_unsigned (); /* string_table. */ afdo_string_table = new string_table (); if (!afdo_string_table->read()) { error ("cannot read string table from %s", auto_profile_file); return; } /* autofdo_source_profile. */ afdo_source_profile = autofdo_source_profile::create (); if (afdo_source_profile == NULL) { error ("cannot read function profile from %s", auto_profile_file); return; } /* autofdo_module_profile. */ fake_read_autofdo_module_profile (); /* Read in the working set. */ if (gcov_read_unsigned () != GCOV_TAG_AFDO_WORKING_SET) { error ("cannot read working set from %s", auto_profile_file); return; } /* Skip the length of the section. */ gcov_read_unsigned (); gcov_working_set_t set[128]; for (unsigned i = 0; i < 128; i++) { set[i].num_counters = gcov_read_unsigned (); set[i].min_counter = gcov_read_counter (); } add_working_set (set); } /* From AutoFDO profiles, find values inside STMT for that we want to measure histograms for indirect-call optimization. This function is actually served for 2 purposes: * before annotation, we need to mark histogram, promote and inline * after annotation, we just need to mark, and let follow-up logic to decide if it needs to promote and inline. */ static void afdo_indirect_call (gimple_stmt_iterator *gsi, const icall_target_map &map, bool transform) { gimple *gs = gsi_stmt (*gsi); tree callee; if (map.size () == 0) return; gcall *stmt = dyn_cast (gs); if ((!stmt) || gimple_call_fndecl (stmt) != NULL_TREE) return; callee = gimple_call_fn (stmt); histogram_value hist = gimple_alloc_histogram_value ( cfun, HIST_TYPE_INDIR_CALL, stmt, callee); hist->n_counters = 3; hist->hvalue.counters = XNEWVEC (gcov_type, hist->n_counters); gimple_add_histogram_value (cfun, stmt, hist); gcov_type total = 0; icall_target_map::const_iterator max_iter = map.end (); for (icall_target_map::const_iterator iter = map.begin (); iter != map.end (); ++iter) { total += iter->second; if (max_iter == map.end () || max_iter->second < iter->second) max_iter = iter; } hist->hvalue.counters[0] = (unsigned long long)afdo_string_table->get_name (max_iter->first); hist->hvalue.counters[1] = max_iter->second; hist->hvalue.counters[2] = total; if (!transform) return; struct cgraph_edge *indirect_edge = cgraph_node::get (current_function_decl)->get_edge (stmt); struct cgraph_node *direct_call = cgraph_node::get_for_asmname ( get_identifier ((const char *) hist->hvalue.counters[0])); if (dump_file) { fprintf (dump_file, "Indirect call -> direct call "); print_generic_expr (dump_file, callee, TDF_SLIM); fprintf (dump_file, " => "); print_generic_expr (dump_file, direct_call->decl, TDF_SLIM); } if (direct_call == NULL || !check_ic_target (stmt, direct_call)) { if (dump_file) fprintf (dump_file, " not transforming\n"); return; } if (DECL_STRUCT_FUNCTION (direct_call->decl) == NULL) { if (dump_file) fprintf (dump_file, " no declaration\n"); return; } if (dump_file) { fprintf (dump_file, " transformation on insn "); print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); fprintf (dump_file, "\n"); } /* FIXME: Count should be initialized. */ struct cgraph_edge *new_edge = indirect_edge->make_speculative (direct_call, profile_count::uninitialized (), 0); new_edge->redirect_call_stmt_to_callee (); gimple_remove_histogram_value (cfun, stmt, hist); inline_call (new_edge, true, NULL, NULL, false); } /* From AutoFDO profiles, find values inside STMT for that we want to measure histograms and adds them to list VALUES. */ static void afdo_vpt (gimple_stmt_iterator *gsi, const icall_target_map &map, bool transform) { afdo_indirect_call (gsi, map, transform); } typedef std::set bb_set; typedef std::set edge_set; static bool is_bb_annotated (const basic_block bb, const bb_set &annotated) { return annotated.find (bb) != annotated.end (); } static void set_bb_annotated (basic_block bb, bb_set *annotated) { annotated->insert (bb); } static bool is_edge_annotated (const edge e, const edge_set &annotated) { return annotated.find (e) != annotated.end (); } static void set_edge_annotated (edge e, edge_set *annotated) { annotated->insert (e); } /* For a given BB, set its execution count. Attach value profile if a stmt is not in PROMOTED, because we only want to promote an indirect call once. Return TRUE if BB is annotated. */ static bool afdo_set_bb_count (basic_block bb, const stmt_set &promoted) { gimple_stmt_iterator gsi; edge e; edge_iterator ei; gcov_type max_count = 0; bool has_annotated = false; for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { count_info info; gimple *stmt = gsi_stmt (gsi); if (gimple_clobber_p (stmt) || is_gimple_debug (stmt)) continue; if (afdo_source_profile->get_count_info (stmt, &info)) { if (info.count > max_count) max_count = info.count; has_annotated = true; if (info.targets.size () > 0 && promoted.find (stmt) == promoted.end ()) afdo_vpt (&gsi, info.targets, false); } } if (!has_annotated) return false; for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) afdo_source_profile->mark_annotated (gimple_location (gsi_stmt (gsi))); for (gphi_iterator gpi = gsi_start_phis (bb); !gsi_end_p (gpi); gsi_next (&gpi)) { gphi *phi = gpi.phi (); size_t i; for (i = 0; i < gimple_phi_num_args (phi); i++) afdo_source_profile->mark_annotated (gimple_phi_arg_location (phi, i)); } FOR_EACH_EDGE (e, ei, bb->succs) afdo_source_profile->mark_annotated (e->goto_locus); bb->count = profile_count::from_gcov_type (max_count); return true; } /* BB1 and BB2 are in an equivalent class iff: 1. BB1 dominates BB2. 2. BB2 post-dominates BB1. 3. BB1 and BB2 are in the same loop nest. This function finds the equivalent class for each basic block, and stores a pointer to the first BB in its equivalent class. Meanwhile, set bb counts for the same equivalent class to be idenical. Update ANNOTATED_BB for the first BB in its equivalent class. */ static void afdo_find_equiv_class (bb_set *annotated_bb) { basic_block bb; FOR_ALL_BB_FN (bb, cfun) bb->aux = NULL; FOR_ALL_BB_FN (bb, cfun) { vec dom_bbs; basic_block bb1; int i; if (bb->aux != NULL) continue; bb->aux = bb; dom_bbs = get_dominated_by (CDI_DOMINATORS, bb); FOR_EACH_VEC_ELT (dom_bbs, i, bb1) if (bb1->aux == NULL && dominated_by_p (CDI_POST_DOMINATORS, bb, bb1) && bb1->loop_father == bb->loop_father) { bb1->aux = bb; if (bb1->count > bb->count && is_bb_annotated (bb1, *annotated_bb)) { bb->count = bb1->count; set_bb_annotated (bb, annotated_bb); } } dom_bbs = get_dominated_by (CDI_POST_DOMINATORS, bb); FOR_EACH_VEC_ELT (dom_bbs, i, bb1) if (bb1->aux == NULL && dominated_by_p (CDI_DOMINATORS, bb, bb1) && bb1->loop_father == bb->loop_father) { bb1->aux = bb; if (bb1->count > bb->count && is_bb_annotated (bb1, *annotated_bb)) { bb->count = bb1->count; set_bb_annotated (bb, annotated_bb); } } } } /* If a basic block's count is known, and only one of its in/out edges' count is unknown, its count can be calculated. Meanwhile, if all of the in/out edges' counts are known, then the basic block's unknown count can also be calculated. IS_SUCC is true if out edges of a basic blocks are examined. Update ANNOTATED_BB and ANNOTATED_EDGE accordingly. Return TRUE if any basic block/edge count is changed. */ static bool afdo_propagate_edge (bool is_succ, bb_set *annotated_bb, edge_set *annotated_edge) { basic_block bb; bool changed = false; FOR_EACH_BB_FN (bb, cfun) { edge e, unknown_edge = NULL; edge_iterator ei; int num_unknown_edge = 0; profile_count total_known_count = profile_count::zero (); FOR_EACH_EDGE (e, ei, is_succ ? bb->succs : bb->preds) if (!is_edge_annotated (e, *annotated_edge)) num_unknown_edge++, unknown_edge = e; else total_known_count += e->count; if (num_unknown_edge == 0) { if (total_known_count > bb->count) { bb->count = total_known_count; changed = true; } if (!is_bb_annotated (bb, *annotated_bb)) { set_bb_annotated (bb, annotated_bb); changed = true; } } else if (num_unknown_edge == 1 && is_bb_annotated (bb, *annotated_bb)) { unknown_edge->count = bb->count - total_known_count; set_edge_annotated (unknown_edge, annotated_edge); changed = true; } } return changed; } /* Special propagation for circuit expressions. Because GCC translates control flow into data flow for circuit expressions. E.g. BB1: if (a && b) BB2 else BB3 will be translated into: BB1: if (a) goto BB.t1 else goto BB.t3 BB.t1: if (b) goto BB.t2 else goto BB.t3 BB.t2: goto BB.t3 BB.t3: tmp = PHI (0 (BB1), 0 (BB.t1), 1 (BB.t2) if (tmp) goto BB2 else goto BB3 In this case, we need to propagate through PHI to determine the edge count of BB1->BB.t1, BB.t1->BB.t2. Update ANNOTATED_EDGE accordingly. */ static void afdo_propagate_circuit (const bb_set &annotated_bb, edge_set *annotated_edge) { basic_block bb; FOR_ALL_BB_FN (bb, cfun) { gimple *def_stmt; tree cmp_rhs, cmp_lhs; gimple *cmp_stmt = last_stmt (bb); edge e; edge_iterator ei; if (!cmp_stmt || gimple_code (cmp_stmt) != GIMPLE_COND) continue; cmp_rhs = gimple_cond_rhs (cmp_stmt); cmp_lhs = gimple_cond_lhs (cmp_stmt); if (!TREE_CONSTANT (cmp_rhs) || !(integer_zerop (cmp_rhs) || integer_onep (cmp_rhs))) continue; if (TREE_CODE (cmp_lhs) != SSA_NAME) continue; if (!is_bb_annotated (bb, annotated_bb)) continue; def_stmt = SSA_NAME_DEF_STMT (cmp_lhs); while (def_stmt && gimple_code (def_stmt) == GIMPLE_ASSIGN && gimple_assign_single_p (def_stmt) && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME) def_stmt = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (def_stmt)); if (!def_stmt) continue; gphi *phi_stmt = dyn_cast (def_stmt); if (!phi_stmt) continue; FOR_EACH_EDGE (e, ei, bb->succs) { unsigned i, total = 0; edge only_one; bool check_value_one = (((integer_onep (cmp_rhs)) ^ (gimple_cond_code (cmp_stmt) == EQ_EXPR)) ^ ((e->flags & EDGE_TRUE_VALUE) != 0)); if (!is_edge_annotated (e, *annotated_edge)) continue; for (i = 0; i < gimple_phi_num_args (phi_stmt); i++) { tree val = gimple_phi_arg_def (phi_stmt, i); edge ep = gimple_phi_arg_edge (phi_stmt, i); if (!TREE_CONSTANT (val) || !(integer_zerop (val) || integer_onep (val))) continue; if (check_value_one ^ integer_onep (val)) continue; total++; only_one = ep; if (e->probability == 0 && !is_edge_annotated (ep, *annotated_edge)) { ep->probability = 0; ep->count = profile_count::zero (); set_edge_annotated (ep, annotated_edge); } } if (total == 1 && !is_edge_annotated (only_one, *annotated_edge)) { only_one->probability = e->probability; only_one->count = e->count; set_edge_annotated (only_one, annotated_edge); } } } } /* Propagate the basic block count and edge count on the control flow graph. We do the propagation iteratively until stablize. */ static void afdo_propagate (bb_set *annotated_bb, edge_set *annotated_edge) { basic_block bb; bool changed = true; int i = 0; FOR_ALL_BB_FN (bb, cfun) { bb->count = ((basic_block)bb->aux)->count; if (is_bb_annotated ((basic_block)bb->aux, *annotated_bb)) set_bb_annotated (bb, annotated_bb); } while (changed && i++ < 10) { changed = false; if (afdo_propagate_edge (true, annotated_bb, annotated_edge)) changed = true; if (afdo_propagate_edge (false, annotated_bb, annotated_edge)) changed = true; afdo_propagate_circuit (*annotated_bb, annotated_edge); } } /* Propagate counts on control flow graph and calculate branch probabilities. */ static void afdo_calculate_branch_prob (bb_set *annotated_bb, edge_set *annotated_edge) { basic_block bb; bool has_sample = false; FOR_EACH_BB_FN (bb, cfun) { if (bb->count > profile_count::zero ()) { has_sample = true; break; } } if (!has_sample) return; calculate_dominance_info (CDI_POST_DOMINATORS); calculate_dominance_info (CDI_DOMINATORS); loop_optimizer_init (0); afdo_find_equiv_class (annotated_bb); afdo_propagate (annotated_bb, annotated_edge); FOR_EACH_BB_FN (bb, cfun) { edge e; edge_iterator ei; int num_unknown_succ = 0; profile_count total_count = profile_count::zero (); FOR_EACH_EDGE (e, ei, bb->succs) { if (!is_edge_annotated (e, *annotated_edge)) num_unknown_succ++; else total_count += e->count; } if (num_unknown_succ == 0 && total_count > profile_count::zero ()) { FOR_EACH_EDGE (e, ei, bb->succs) e->probability = e->count.probability_in (total_count); } } FOR_ALL_BB_FN (bb, cfun) { edge e; edge_iterator ei; FOR_EACH_EDGE (e, ei, bb->succs) e->count = bb->count.apply_probability (e->probability); bb->aux = NULL; } loop_optimizer_finalize (); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); } /* Perform value profile transformation using AutoFDO profile. Add the promoted stmts to PROMOTED_STMTS. Return TRUE if there is any indirect call promoted. */ static bool afdo_vpt_for_early_inline (stmt_set *promoted_stmts) { basic_block bb; if (afdo_source_profile->get_function_instance_by_decl ( current_function_decl) == NULL) return false; compute_fn_summary (cgraph_node::get (current_function_decl), true); bool has_vpt = false; FOR_EACH_BB_FN (bb, cfun) { if (!has_indirect_call (bb)) continue; gimple_stmt_iterator gsi; gcov_type bb_count = 0; for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { count_info info; gimple *stmt = gsi_stmt (gsi); if (afdo_source_profile->get_count_info (stmt, &info)) bb_count = MAX (bb_count, info.count); } for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) { gcall *stmt = dyn_cast (gsi_stmt (gsi)); /* IC_promotion and early_inline_2 is done in multiple iterations. No need to promoted the stmt if its in promoted_stmts (means it is already been promoted in the previous iterations). */ if ((!stmt) || gimple_call_fn (stmt) == NULL || TREE_CODE (gimple_call_fn (stmt)) == FUNCTION_DECL || promoted_stmts->find (stmt) != promoted_stmts->end ()) continue; count_info info; afdo_source_profile->get_count_info (stmt, &info); info.count = bb_count; if (afdo_source_profile->update_inlined_ind_target (stmt, &info)) { /* Promote the indirect call and update the promoted_stmts. */ promoted_stmts->insert (stmt); afdo_vpt (&gsi, info.targets, true); has_vpt = true; } } } if (has_vpt) { unsigned todo = optimize_inline_calls (current_function_decl); if (todo & TODO_update_ssa_any) update_ssa (TODO_update_ssa); return true; } return false; } /* Annotate auto profile to the control flow graph. Do not annotate value profile for stmts in PROMOTED_STMTS. */ static void afdo_annotate_cfg (const stmt_set &promoted_stmts) { basic_block bb; bb_set annotated_bb; edge_set annotated_edge; const function_instance *s = afdo_source_profile->get_function_instance_by_decl ( current_function_decl); if (s == NULL) return; cgraph_node::get (current_function_decl)->count = profile_count::from_gcov_type (s->head_count ()); ENTRY_BLOCK_PTR_FOR_FN (cfun)->count = profile_count::from_gcov_type (s->head_count ()); profile_count max_count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count; FOR_EACH_BB_FN (bb, cfun) { edge e; edge_iterator ei; bb->count = profile_count::uninitialized (); FOR_EACH_EDGE (e, ei, bb->succs) e->count = profile_count::uninitialized (); if (afdo_set_bb_count (bb, promoted_stmts)) set_bb_annotated (bb, &annotated_bb); if (bb->count > max_count) max_count = bb->count; } if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->count > ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->count) { ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count; set_bb_annotated (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb, &annotated_bb); } if (ENTRY_BLOCK_PTR_FOR_FN (cfun)->count > EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb->count) { EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb->count = ENTRY_BLOCK_PTR_FOR_FN (cfun)->count; set_bb_annotated (EXIT_BLOCK_PTR_FOR_FN (cfun)->prev_bb, &annotated_bb); } afdo_source_profile->mark_annotated ( DECL_SOURCE_LOCATION (current_function_decl)); afdo_source_profile->mark_annotated (cfun->function_start_locus); afdo_source_profile->mark_annotated (cfun->function_end_locus); if (max_count > profile_count::zero ()) { afdo_calculate_branch_prob (&annotated_bb, &annotated_edge); counts_to_freqs (); profile_status_for_fn (cfun) = PROFILE_READ; } if (flag_value_profile_transformations) { gimple_value_profile_transformations (); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); update_ssa (TODO_update_ssa); } } /* Wrapper function to invoke early inliner. */ static void early_inline () { compute_fn_summary (cgraph_node::get (current_function_decl), true); unsigned todo = early_inliner (cfun); if (todo & TODO_update_ssa_any) update_ssa (TODO_update_ssa); } /* Use AutoFDO profile to annoate the control flow graph. Return the todo flag. */ static unsigned int auto_profile (void) { struct cgraph_node *node; if (symtab->state == FINISHED) return 0; init_node_map (true); profile_info = autofdo::afdo_profile_info; FOR_EACH_FUNCTION (node) { if (!gimple_has_body_p (node->decl)) continue; /* Don't profile functions produced for builtin stuff. */ if (DECL_SOURCE_LOCATION (node->decl) == BUILTINS_LOCATION) continue; push_cfun (DECL_STRUCT_FUNCTION (node->decl)); /* First do indirect call promotion and early inline to make the IR match the profiled binary before actual annotation. This is needed because an indirect call might have been promoted and inlined in the profiled binary. If we do not promote and inline these indirect calls before annotation, the profile for these promoted functions will be lost. e.g. foo() --indirect_call--> bar() In profiled binary, the callsite is promoted and inlined, making the profile look like: foo: { loc_foo_1: count_1 bar@loc_foo_2: { loc_bar_1: count_2 loc_bar_2: count_3 } } Before AutoFDO pass, loc_foo_2 is not promoted thus not inlined. If we perform annotation on it, the profile inside bar@loc_foo2 will be wasted. To avoid this, we promote loc_foo_2 and inline the promoted bar function before annotation, so the profile inside bar@loc_foo2 will be useful. */ autofdo::stmt_set promoted_stmts; for (int i = 0; i < PARAM_VALUE (PARAM_EARLY_INLINER_MAX_ITERATIONS); i++) { if (!flag_value_profile_transformations || !autofdo::afdo_vpt_for_early_inline (&promoted_stmts)) break; early_inline (); } early_inline (); autofdo::afdo_annotate_cfg (promoted_stmts); compute_function_frequency (); /* Local pure-const may imply need to fixup the cfg. */ if (execute_fixup_cfg () & TODO_cleanup_cfg) cleanup_tree_cfg (); free_dominance_info (CDI_DOMINATORS); free_dominance_info (CDI_POST_DOMINATORS); cgraph_edge::rebuild_edges (); compute_fn_summary (cgraph_node::get (current_function_decl), true); pop_cfun (); } return TODO_rebuild_cgraph_edges; } } /* namespace autofdo. */ /* Read the profile from the profile data file. */ void read_autofdo_file (void) { if (auto_profile_file == NULL) auto_profile_file = DEFAULT_AUTO_PROFILE_FILE; autofdo::afdo_profile_info = (struct gcov_ctr_summary *)xcalloc ( 1, sizeof (struct gcov_ctr_summary)); autofdo::afdo_profile_info->runs = 1; autofdo::afdo_profile_info->sum_max = 0; autofdo::afdo_profile_info->sum_all = 0; /* Read the profile from the profile file. */ autofdo::read_profile (); } /* Free the resources. */ void end_auto_profile (void) { delete autofdo::afdo_source_profile; delete autofdo::afdo_string_table; profile_info = NULL; } /* Returns TRUE if EDGE is hot enough to be inlined early. */ bool afdo_callsite_hot_enough_for_early_inline (struct cgraph_edge *edge) { gcov_type count = autofdo::afdo_source_profile->get_callsite_total_count (edge); if (count > 0) { bool is_hot; const struct gcov_ctr_summary *saved_profile_info = profile_info; /* At early inline stage, profile_info is not set yet. We need to temporarily set it to afdo_profile_info to calculate hotness. */ profile_info = autofdo::afdo_profile_info; is_hot = maybe_hot_count_p (NULL, profile_count::from_gcov_type (count)); profile_info = saved_profile_info; return is_hot; } return false; } namespace { const pass_data pass_data_ipa_auto_profile = { SIMPLE_IPA_PASS, "afdo", /* name */ OPTGROUP_NONE, /* optinfo_flags */ TV_IPA_AUTOFDO, /* tv_id */ 0, /* properties_required */ 0, /* properties_provided */ 0, /* properties_destroyed */ 0, /* todo_flags_start */ 0, /* todo_flags_finish */ }; class pass_ipa_auto_profile : public simple_ipa_opt_pass { public: pass_ipa_auto_profile (gcc::context *ctxt) : simple_ipa_opt_pass (pass_data_ipa_auto_profile, ctxt) { } /* opt_pass methods: */ virtual bool gate (function *) { return flag_auto_profile; } virtual unsigned int execute (function *) { return autofdo::auto_profile (); } }; // class pass_ipa_auto_profile } // anon namespace simple_ipa_opt_pass * make_pass_ipa_auto_profile (gcc::context *ctxt) { return new pass_ipa_auto_profile (ctxt); }