| /* Callgraph based analysis of static variables. |
| Copyright (C) 2004-2022 Free Software Foundation, Inc. |
| Contributed by Kenneth Zadeck <zadeck@naturalbridge.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 |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* This file gathers information about how variables whose scope is |
| confined to the compilation unit are used. |
| |
| The transitive call site specific clobber effects are computed |
| for the variables whose scope is contained within this compilation |
| unit. |
| |
| First each function and static variable initialization is analyzed |
| to determine which local static variables are either read, written, |
| or have their address taken. Any local static that has its address |
| taken is removed from consideration. Once the local read and |
| writes are determined, a transitive closure of this information is |
| performed over the call graph to determine the worst case set of |
| side effects of each call. In later parts of the compiler, these |
| local and global sets are examined to make the call clobbering less |
| traumatic, promote some statics to registers, and improve aliasing |
| information. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "backend.h" |
| #include "tree.h" |
| #include "gimple.h" |
| #include "tree-pass.h" |
| #include "cgraph.h" |
| #include "data-streamer.h" |
| #include "calls.h" |
| #include "ipa-utils.h" |
| #include "ipa-reference.h" |
| #include "alloc-pool.h" |
| #include "symbol-summary.h" |
| |
| /* The static variables defined within the compilation unit that are |
| loaded or stored directly by function that owns this structure. */ |
| |
| struct ipa_reference_local_vars_info_d |
| { |
| bitmap statics_read; |
| bitmap statics_written; |
| }; |
| |
| /* Statics that are read and written by some set of functions. The |
| local ones are based on the loads and stores local to the function. |
| The global ones are based on the local info as well as the |
| transitive closure of the functions that are called. */ |
| |
| struct ipa_reference_global_vars_info_d |
| { |
| bitmap statics_read; |
| bitmap statics_written; |
| }; |
| |
| /* Information we save about every function after ipa-reference is completed. */ |
| |
| struct ipa_reference_optimization_summary_d |
| { |
| bitmap statics_read; |
| bitmap statics_written; |
| }; |
| |
| typedef ipa_reference_local_vars_info_d *ipa_reference_local_vars_info_t; |
| typedef ipa_reference_global_vars_info_d *ipa_reference_global_vars_info_t; |
| typedef ipa_reference_optimization_summary_d * |
| ipa_reference_optimization_summary_t; |
| |
| struct ipa_reference_vars_info_d |
| { |
| struct ipa_reference_local_vars_info_d local; |
| struct ipa_reference_global_vars_info_d global; |
| }; |
| |
| typedef struct ipa_reference_vars_info_d *ipa_reference_vars_info_t; |
| |
| /* This map contains all of the static variables that are |
| being considered by the compilation level alias analysis. */ |
| typedef hash_map<tree, int> reference_vars_map_t; |
| static reference_vars_map_t *ipa_reference_vars_map; |
| static int ipa_reference_vars_uids; |
| static vec<tree> *reference_vars_to_consider; |
| varpool_node_hook_list *varpool_node_hooks; |
| |
| /* Set of all interesting module statics. A bit is set for every module |
| static we are considering. This is added to the local info when asm |
| code is found that clobbers all memory. */ |
| static bitmap all_module_statics; |
| /* Zero bitmap. */ |
| static bitmap no_module_statics; |
| /* Set of all statics that should be ignored because they are touched by |
| -fno-ipa-reference code. */ |
| static bitmap ignore_module_statics; |
| |
| /* Obstack holding bitmaps of local analysis (live from analysis to |
| propagation) */ |
| static bitmap_obstack local_info_obstack; |
| /* Obstack holding global analysis live forever. */ |
| static bitmap_obstack optimization_summary_obstack; |
| |
| class ipa_ref_var_info_summary_t: public fast_function_summary |
| <ipa_reference_vars_info_d *, va_heap> |
| { |
| public: |
| ipa_ref_var_info_summary_t (symbol_table *symtab): |
| fast_function_summary <ipa_reference_vars_info_d *, va_heap> (symtab) {} |
| }; |
| |
| static ipa_ref_var_info_summary_t *ipa_ref_var_info_summaries = NULL; |
| |
| class ipa_ref_opt_summary_t: public fast_function_summary |
| <ipa_reference_optimization_summary_d *, va_heap> |
| { |
| public: |
| ipa_ref_opt_summary_t (symbol_table *symtab): |
| fast_function_summary <ipa_reference_optimization_summary_d *, va_heap> (symtab) {} |
| |
| void remove (cgraph_node *src_node, |
| ipa_reference_optimization_summary_d *data) final override; |
| void duplicate (cgraph_node *src_node, cgraph_node *dst_node, |
| ipa_reference_optimization_summary_d *src_data, |
| ipa_reference_optimization_summary_d *dst_data) final override; |
| }; |
| |
| static ipa_ref_opt_summary_t *ipa_ref_opt_sum_summaries = NULL; |
| |
| /* Return ID used by ipa-reference bitmaps. -1 if failed. */ |
| int |
| ipa_reference_var_uid (tree t) |
| { |
| if (!ipa_reference_vars_map) |
| return -1; |
| int *id = ipa_reference_vars_map->get |
| (symtab_node::get (t)->ultimate_alias_target (NULL)->decl); |
| if (!id) |
| return -1; |
| return *id; |
| } |
| |
| /* Return ID used by ipa-reference bitmaps. Create new entry if |
| T is not in map. Set EXISTED accordinly */ |
| int |
| ipa_reference_var_get_or_insert_uid (tree t, bool *existed) |
| { |
| int &id = ipa_reference_vars_map->get_or_insert |
| (symtab_node::get (t)->ultimate_alias_target (NULL)->decl, existed); |
| if (!*existed) |
| id = ipa_reference_vars_uids++; |
| return id; |
| } |
| |
| /* Return the ipa_reference_vars structure starting from the cgraph NODE. */ |
| static inline ipa_reference_vars_info_t |
| get_reference_vars_info (struct cgraph_node *node) |
| { |
| if (ipa_ref_var_info_summaries == NULL) |
| return NULL; |
| |
| ipa_reference_vars_info_t v = ipa_ref_var_info_summaries->get (node); |
| return v == NULL ? NULL : v; |
| } |
| |
| /* Return the ipa_reference_vars structure starting from the cgraph NODE. */ |
| static inline ipa_reference_optimization_summary_t |
| get_reference_optimization_summary (struct cgraph_node *node) |
| { |
| if (ipa_ref_opt_sum_summaries == NULL) |
| return NULL; |
| |
| ipa_reference_optimization_summary_t v |
| = ipa_ref_opt_sum_summaries->get (node); |
| |
| return v == NULL ? NULL : v; |
| } |
| |
| /* Return a bitmap indexed by ipa_reference_var_uid for the static variables |
| that are *not* read during the execution of the function FN. Returns |
| NULL if no data is available. */ |
| |
| bitmap |
| ipa_reference_get_read_global (struct cgraph_node *fn) |
| { |
| if (!opt_for_fn (current_function_decl, flag_ipa_reference)) |
| return NULL; |
| |
| enum availability avail; |
| struct cgraph_node *fn2 = fn->function_symbol (&avail); |
| ipa_reference_optimization_summary_t info = |
| get_reference_optimization_summary (fn2); |
| |
| if (info |
| && (avail >= AVAIL_AVAILABLE |
| || (avail == AVAIL_INTERPOSABLE |
| && flags_from_decl_or_type (fn->decl) & ECF_LEAF)) |
| && opt_for_fn (fn2->decl, flag_ipa_reference)) |
| return info->statics_read; |
| else if (avail == AVAIL_NOT_AVAILABLE |
| && flags_from_decl_or_type (fn->decl) & ECF_LEAF) |
| return no_module_statics; |
| else |
| return NULL; |
| } |
| |
| /* Return a bitmap indexed by ipa_reference_var_uid for the static variables |
| that are *not* written during the execution of the function FN. Note |
| that variables written may or may not be read during the function |
| call. Returns NULL if no data is available. */ |
| |
| bitmap |
| ipa_reference_get_written_global (struct cgraph_node *fn) |
| { |
| if (!opt_for_fn (current_function_decl, flag_ipa_reference)) |
| return NULL; |
| |
| enum availability avail; |
| struct cgraph_node *fn2 = fn->function_symbol (&avail); |
| ipa_reference_optimization_summary_t info = |
| get_reference_optimization_summary (fn2); |
| |
| if (info |
| && (avail >= AVAIL_AVAILABLE |
| || (avail == AVAIL_INTERPOSABLE |
| && flags_from_decl_or_type (fn->decl) & ECF_LEAF)) |
| && opt_for_fn (fn2->decl, flag_ipa_reference)) |
| return info->statics_written; |
| else if (avail == AVAIL_NOT_AVAILABLE |
| && flags_from_decl_or_type (fn->decl) & ECF_LEAF) |
| return no_module_statics; |
| else |
| return NULL; |
| } |
| |
| |
| /* Hepler for is_proper_for_analysis. */ |
| static bool |
| is_improper (symtab_node *n, void *v ATTRIBUTE_UNUSED) |
| { |
| tree t = n->decl; |
| /* If the variable has the "used" attribute, treat it as if it had a |
| been touched by the devil. */ |
| if (DECL_PRESERVE_P (t)) |
| return true; |
| |
| /* Do not want to do anything with volatile except mark any |
| function that uses one to be not const or pure. */ |
| if (TREE_THIS_VOLATILE (t)) |
| return true; |
| |
| /* We do not need to analyze readonly vars, we already know they do not |
| alias. */ |
| if (TREE_READONLY (t)) |
| return true; |
| |
| /* We cannot track variables with address taken. */ |
| if (TREE_ADDRESSABLE (t)) |
| return true; |
| |
| /* TODO: We could track public variables that are not addressable, but |
| currently frontends don't give us those. */ |
| if (TREE_PUBLIC (t)) |
| return true; |
| |
| return false; |
| } |
| |
| /* Return true if the variable T is the right kind of static variable to |
| perform compilation unit scope escape analysis. */ |
| |
| static inline bool |
| is_proper_for_analysis (tree t) |
| { |
| int id = ipa_reference_var_uid (t); |
| |
| if (id != -1 && bitmap_bit_p (ignore_module_statics, id)) |
| return false; |
| |
| if (symtab_node::get (t) |
| ->call_for_symbol_and_aliases (is_improper, NULL, true)) |
| return false; |
| |
| return true; |
| } |
| |
| /* Lookup the tree node for the static variable that has UID and |
| convert the name to a string for debugging. */ |
| |
| static const char * |
| get_static_name (int index) |
| { |
| return fndecl_name ((*reference_vars_to_consider)[index]); |
| } |
| |
| /* Dump a set of static vars to FILE. */ |
| static void |
| dump_static_vars_set_to_file (FILE *f, bitmap set) |
| { |
| unsigned int index; |
| bitmap_iterator bi; |
| if (set == NULL) |
| return; |
| else if (set == all_module_statics) |
| fprintf (f, "ALL"); |
| else if (set == no_module_statics) |
| fprintf (f, "NO"); |
| else |
| EXECUTE_IF_SET_IN_BITMAP (set, 0, index, bi) |
| { |
| fprintf (f, "%s ", get_static_name (index)); |
| } |
| } |
| |
| /* Compute X |= Y, taking into account the possibility that |
| either X or Y is already the maximum set. |
| Return true if X is the maximum set after taking the union with Y. */ |
| |
| static bool |
| union_static_var_sets (bitmap &x, bitmap y) |
| { |
| if (x != all_module_statics) |
| { |
| if (y == all_module_statics) |
| { |
| BITMAP_FREE (x); |
| x = all_module_statics; |
| } |
| else if (bitmap_ior_into (x, y)) |
| { |
| /* The union may have reduced X to the maximum set. |
| In that case, we want to make that visible explicitly. |
| Even though bitmap_equal_p can be very expensive, it |
| turns out to be an overall win to check this here for |
| an LTO bootstrap of GCC itself. Liberally extrapoliate |
| that result to be applicable to all cases. */ |
| if (bitmap_equal_p (x, all_module_statics)) |
| { |
| BITMAP_FREE (x); |
| x = all_module_statics; |
| } |
| } |
| } |
| return x == all_module_statics; |
| } |
| |
| /* Return a copy of SET on the bitmap obstack containing SET. |
| But if SET is NULL or the maximum set, return that instead. */ |
| |
| static bitmap |
| copy_static_var_set (bitmap set, bool for_propagation) |
| { |
| if (set == NULL || set == all_module_statics) |
| return set; |
| if (!for_propagation && set == no_module_statics) |
| return set; |
| bitmap_obstack *o = set->obstack; |
| gcc_checking_assert (o); |
| bitmap copy = BITMAP_ALLOC (o); |
| bitmap_copy (copy, set); |
| return copy; |
| } |
| |
| /* Compute the union all of the statics read and written by every callee of X |
| into X_GLOBAL->statics_read and X_GLOBAL->statics_written. X_GLOBAL is |
| actually the set representing the cycle containing X. If the read and |
| written sets of X_GLOBAL has been reduced to the maximum set, we don't |
| have to look at the remaining callees. */ |
| |
| static void |
| propagate_bits (ipa_reference_global_vars_info_t x_global, struct cgraph_node *x) |
| { |
| struct cgraph_edge *e; |
| bool read_all = x_global->statics_read == all_module_statics; |
| bool write_all = x_global->statics_written == all_module_statics; |
| for (e = x->callees; |
| e && !(read_all && write_all); |
| e = e->next_callee) |
| { |
| enum availability avail; |
| struct cgraph_node *y = e->callee->function_symbol (&avail); |
| if (!y) |
| continue; |
| |
| /* Only look into nodes we can propagate something. */ |
| int flags = flags_from_decl_or_type (y->decl); |
| if (opt_for_fn (y->decl, flag_ipa_reference) |
| && (avail > AVAIL_INTERPOSABLE |
| || (avail == AVAIL_INTERPOSABLE && (flags & ECF_LEAF)))) |
| { |
| if (get_reference_vars_info (y)) |
| { |
| ipa_reference_vars_info_t y_info = get_reference_vars_info (y); |
| ipa_reference_global_vars_info_t y_global = &y_info->global; |
| |
| /* Calls in the current cycle do not have their global set |
| computed yet (but everything else does because we're |
| visiting nodes in topological order). */ |
| if (!y_global->statics_read) |
| continue; |
| |
| /* If the function is const, it reads no memory even if it |
| seems so to local analysis. */ |
| if (flags & ECF_CONST) |
| continue; |
| |
| union_static_var_sets (x_global->statics_read, |
| y_global->statics_read); |
| |
| /* If the function is pure, it has no stores even if it |
| seems so to local analysis. If we cannot return from |
| the function, we can safely ignore the call. */ |
| if ((flags & ECF_PURE) |
| || e->cannot_lead_to_return_p ()) |
| continue; |
| |
| union_static_var_sets (x_global->statics_written, |
| y_global->statics_written); |
| } |
| else |
| gcc_unreachable (); |
| } |
| } |
| } |
| |
| /* Delete NODE from map. */ |
| |
| static void |
| varpool_removal_hook (varpool_node *node, void *) |
| { |
| ipa_reference_vars_map->remove (node->decl); |
| } |
| |
| static bool ipa_init_p = false; |
| |
| /* The init routine for analyzing global static variable usage. See |
| comments at top for description. */ |
| static void |
| ipa_init (void) |
| { |
| if (ipa_init_p) |
| return; |
| |
| ipa_init_p = true; |
| |
| if (dump_file) |
| vec_alloc (reference_vars_to_consider, 10); |
| |
| if (ipa_ref_opt_sum_summaries != NULL) |
| { |
| delete ipa_ref_opt_sum_summaries; |
| ipa_ref_opt_sum_summaries = NULL; |
| delete ipa_reference_vars_map; |
| } |
| ipa_reference_vars_map = new reference_vars_map_t(257); |
| varpool_node_hooks |
| = symtab->add_varpool_removal_hook (varpool_removal_hook, NULL); |
| ipa_reference_vars_uids = 0; |
| |
| bitmap_obstack_initialize (&local_info_obstack); |
| bitmap_obstack_initialize (&optimization_summary_obstack); |
| all_module_statics = BITMAP_ALLOC (&optimization_summary_obstack); |
| no_module_statics = BITMAP_ALLOC (&optimization_summary_obstack); |
| ignore_module_statics = BITMAP_ALLOC (&optimization_summary_obstack); |
| |
| if (ipa_ref_var_info_summaries == NULL) |
| ipa_ref_var_info_summaries = new ipa_ref_var_info_summary_t (symtab); |
| } |
| |
| |
| /* Set up the persistent info for FN. */ |
| |
| static ipa_reference_local_vars_info_t |
| init_function_info (struct cgraph_node *fn) |
| { |
| ipa_reference_vars_info_t info |
| = ipa_ref_var_info_summaries->get_create (fn); |
| |
| info->local.statics_read = BITMAP_ALLOC (&local_info_obstack); |
| info->local.statics_written = BITMAP_ALLOC (&local_info_obstack); |
| info->global.statics_read = NULL; |
| |
| return &info->local; |
| } |
| |
| |
| /* This is the main routine for finding the reference patterns for |
| global variables within a function FN. */ |
| |
| static void |
| analyze_function (struct cgraph_node *fn) |
| { |
| ipa_reference_local_vars_info_t local; |
| struct ipa_ref *ref = NULL; |
| int i; |
| tree var; |
| |
| if (!opt_for_fn (fn->decl, flag_ipa_reference)) |
| return; |
| local = init_function_info (fn); |
| for (i = 0; fn->iterate_reference (i, ref); i++) |
| { |
| int id; |
| bool existed; |
| if (!is_a <varpool_node *> (ref->referred)) |
| continue; |
| var = ref->referred->decl; |
| if (!is_proper_for_analysis (var)) |
| continue; |
| /* This is a variable we care about. Check if we have seen it |
| before, and if not add it the set of variables we care about. */ |
| id = ipa_reference_var_get_or_insert_uid (var, &existed); |
| if (!existed) |
| { |
| bitmap_set_bit (all_module_statics, id); |
| if (dump_file) |
| reference_vars_to_consider->safe_push (var); |
| } |
| switch (ref->use) |
| { |
| case IPA_REF_LOAD: |
| bitmap_set_bit (local->statics_read, id); |
| break; |
| case IPA_REF_STORE: |
| if (ref->cannot_lead_to_return ()) |
| break; |
| bitmap_set_bit (local->statics_written, id); |
| break; |
| case IPA_REF_ADDR: |
| break; |
| default: |
| gcc_unreachable (); |
| } |
| } |
| |
| if (fn->cannot_return_p ()) |
| bitmap_clear (local->statics_written); |
| } |
| |
| |
| /* Called when new clone is inserted to callgraph late. */ |
| |
| void |
| ipa_ref_opt_summary_t::duplicate (cgraph_node *, cgraph_node *, |
| ipa_reference_optimization_summary_d *ginfo, |
| ipa_reference_optimization_summary_d |
| *dst_ginfo) |
| { |
| dst_ginfo->statics_read = |
| copy_static_var_set (ginfo->statics_read, false); |
| dst_ginfo->statics_written = |
| copy_static_var_set (ginfo->statics_written, false); |
| } |
| |
| /* Called when node is removed. */ |
| |
| void |
| ipa_ref_opt_summary_t::remove (cgraph_node *, |
| ipa_reference_optimization_summary_d *ginfo) |
| { |
| if (ginfo->statics_read |
| && ginfo->statics_read != all_module_statics |
| && ginfo->statics_read != no_module_statics) |
| BITMAP_FREE (ginfo->statics_read); |
| |
| if (ginfo->statics_written |
| && ginfo->statics_written != all_module_statics |
| && ginfo->statics_written != no_module_statics) |
| BITMAP_FREE (ginfo->statics_written); |
| } |
| |
| /* Analyze each function in the cgraph to see which global or statics |
| are read or written. */ |
| |
| static void |
| generate_summary (void) |
| { |
| struct cgraph_node *node; |
| unsigned int index; |
| bitmap_iterator bi; |
| |
| ipa_init (); |
| |
| /* Process all of the functions next. */ |
| FOR_EACH_DEFINED_FUNCTION (node) |
| if (!node->alias && !opt_for_fn (node->decl, flag_ipa_reference)) |
| { |
| struct ipa_ref *ref = NULL; |
| int i; |
| tree var; |
| for (i = 0; node->iterate_reference (i, ref); i++) |
| { |
| if (!is_a <varpool_node *> (ref->referred)) |
| continue; |
| var = ref->referred->decl; |
| if (!is_proper_for_analysis (var)) |
| continue; |
| bitmap_set_bit (ignore_module_statics, ipa_reference_var_uid (var)); |
| } |
| } |
| FOR_EACH_DEFINED_FUNCTION (node) |
| analyze_function (node); |
| |
| if (dump_file) |
| EXECUTE_IF_SET_IN_BITMAP (all_module_statics, 0, index, bi) |
| { |
| fprintf (dump_file, "\nPromotable global:%s (uid=%u)\n", |
| get_static_name (index), index); |
| } |
| |
| if (dump_file) |
| FOR_EACH_DEFINED_FUNCTION (node) |
| if (node->get_availability () >= AVAIL_INTERPOSABLE |
| && opt_for_fn (node->decl, flag_ipa_reference)) |
| { |
| ipa_reference_local_vars_info_t l; |
| unsigned int index; |
| bitmap_iterator bi; |
| |
| l = &get_reference_vars_info (node)->local; |
| fprintf (dump_file, |
| "\nFunction name:%s:", node->dump_name ()); |
| fprintf (dump_file, "\n locals read: "); |
| if (l->statics_read) |
| EXECUTE_IF_SET_IN_BITMAP (l->statics_read, |
| 0, index, bi) |
| { |
| fprintf (dump_file, "%s ", |
| get_static_name (index)); |
| } |
| fprintf (dump_file, "\n locals written: "); |
| if (l->statics_written) |
| EXECUTE_IF_SET_IN_BITMAP (l->statics_written, |
| 0, index, bi) |
| { |
| fprintf (dump_file, "%s ", get_static_name (index)); |
| } |
| } |
| } |
| |
| /* Set READ_ALL/WRITE_ALL based on decl flags of NODE. */ |
| |
| static void |
| read_write_all_from_decl (struct cgraph_node *node, |
| bool &read_all, bool &write_all) |
| { |
| tree decl = node->decl; |
| int flags = flags_from_decl_or_type (decl); |
| if ((flags & ECF_LEAF) |
| && node->get_availability () < AVAIL_INTERPOSABLE) |
| ; |
| else if (flags & ECF_CONST) |
| ; |
| else if ((flags & ECF_PURE) || node->cannot_return_p ()) |
| { |
| read_all = true; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " %s -> read all\n", node->dump_name ()); |
| } |
| else |
| { |
| /* TODO: To be able to produce sane results, we should also handle |
| common builtins, in particular throw. */ |
| read_all = true; |
| write_all = true; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " %s -> read all, write all\n", |
| node->dump_name ()); |
| } |
| } |
| |
| /* Set READ_ALL/WRITE_ALL based on decl flags of NODE or any member |
| in the cycle of NODE. */ |
| |
| static void |
| get_read_write_all_from_node (struct cgraph_node *node, |
| bool &read_all, bool &write_all) |
| { |
| struct cgraph_edge *e, *ie; |
| |
| /* When function is overwritable, we cannot assume anything. */ |
| if (node->get_availability () <= AVAIL_INTERPOSABLE |
| || (node->analyzed && !opt_for_fn (node->decl, flag_ipa_reference))) |
| read_write_all_from_decl (node, read_all, write_all); |
| |
| for (e = node->callees; |
| e && !(read_all && write_all); |
| e = e->next_callee) |
| { |
| enum availability avail; |
| struct cgraph_node *callee = e->callee->function_symbol (&avail); |
| gcc_checking_assert (callee); |
| if (avail <= AVAIL_INTERPOSABLE |
| || (callee->analyzed && !opt_for_fn (callee->decl, |
| flag_ipa_reference))) |
| read_write_all_from_decl (callee, read_all, write_all); |
| } |
| |
| for (ie = node->indirect_calls; |
| ie && !(read_all && write_all); |
| ie = ie->next_callee) |
| if (!(ie->indirect_info->ecf_flags & ECF_CONST)) |
| { |
| read_all = true; |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " indirect call -> read all\n"); |
| if (!ie->cannot_lead_to_return_p () |
| && !(ie->indirect_info->ecf_flags & ECF_PURE)) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " indirect call -> write all\n"); |
| write_all = true; |
| } |
| } |
| } |
| |
| /* Skip edges from and to nodes without ipa_reference enabled. |
| Ignore not available symbols. This leave |
| them out of strongly connected components and makes them easy to skip in the |
| propagation loop bellow. */ |
| |
| static bool |
| ignore_edge_p (cgraph_edge *e) |
| { |
| enum availability avail; |
| cgraph_node *ultimate_target |
| = e->callee->function_or_virtual_thunk_symbol (&avail, e->caller); |
| |
| return (avail < AVAIL_INTERPOSABLE |
| || (avail == AVAIL_INTERPOSABLE |
| && !(flags_from_decl_or_type (e->callee->decl) & ECF_LEAF)) |
| || !opt_for_fn (e->caller->decl, flag_ipa_reference) |
| || !opt_for_fn (ultimate_target->decl, flag_ipa_reference)); |
| } |
| |
| /* Produce the global information by preforming a transitive closure |
| on the local information that was produced by ipa_analyze_function. */ |
| |
| static unsigned int |
| propagate (void) |
| { |
| struct cgraph_node *node; |
| struct cgraph_node **order = |
| XCNEWVEC (struct cgraph_node *, symtab->cgraph_count); |
| int order_pos; |
| int i; |
| bool remove_p; |
| |
| if (dump_file) |
| cgraph_node::dump_cgraph (dump_file); |
| |
| remove_p = ipa_discover_variable_flags (); |
| generate_summary (); |
| |
| /* Propagate the local information through the call graph to produce |
| the global information. All the nodes within a cycle will have |
| the same info so we collapse cycles first. Then we can do the |
| propagation in one pass from the leaves to the roots. */ |
| order_pos = ipa_reduced_postorder (order, true, ignore_edge_p); |
| if (dump_file) |
| ipa_print_order (dump_file, "reduced", order, order_pos); |
| |
| for (i = 0; i < order_pos; i++ ) |
| { |
| unsigned x; |
| struct cgraph_node *w; |
| ipa_reference_vars_info_t node_info; |
| ipa_reference_global_vars_info_t node_g; |
| ipa_reference_local_vars_info_t node_l; |
| bool read_all = false; |
| bool write_all = false; |
| |
| node = order[i]; |
| if (node->alias || !opt_for_fn (node->decl, flag_ipa_reference)) |
| continue; |
| |
| node_info = get_reference_vars_info (node); |
| gcc_assert (node_info); |
| node_l = &node_info->local; |
| node_g = &node_info->global; |
| |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, "Starting cycle with %s\n", node->dump_name ()); |
| |
| vec<cgraph_node *> cycle_nodes = ipa_get_nodes_in_cycle (node); |
| |
| /* If any node in a cycle is read_all or write_all, they all are. */ |
| FOR_EACH_VEC_ELT (cycle_nodes, x, w) |
| { |
| if (dump_file && (dump_flags & TDF_DETAILS)) |
| fprintf (dump_file, " Visiting %s\n", w->dump_asm_name ()); |
| get_read_write_all_from_node (w, read_all, write_all); |
| if (read_all && write_all) |
| break; |
| } |
| |
| /* Initialized the bitmaps global sets for the reduced node. */ |
| if (read_all) |
| node_g->statics_read = all_module_statics; |
| else |
| node_g->statics_read = copy_static_var_set (node_l->statics_read, true); |
| if (write_all) |
| node_g->statics_written = all_module_statics; |
| else |
| node_g->statics_written |
| = copy_static_var_set (node_l->statics_written, true); |
| |
| /* Merge the sets of this cycle with all sets of callees reached |
| from this cycle. */ |
| FOR_EACH_VEC_ELT (cycle_nodes, x, w) |
| { |
| if (read_all && write_all) |
| break; |
| |
| if (w != node) |
| { |
| ipa_reference_vars_info_t w_ri = get_reference_vars_info (w); |
| ipa_reference_local_vars_info_t w_l = &w_ri->local; |
| int flags = flags_from_decl_or_type (w->decl); |
| |
| if (!(flags & ECF_CONST)) |
| read_all = union_static_var_sets (node_g->statics_read, |
| w_l->statics_read); |
| if (!(flags & ECF_PURE) |
| && !w->cannot_return_p ()) |
| write_all = union_static_var_sets (node_g->statics_written, |
| w_l->statics_written); |
| } |
| |
| propagate_bits (node_g, w); |
| } |
| |
| /* All nodes within a cycle have the same global info bitmaps. */ |
| FOR_EACH_VEC_ELT (cycle_nodes, x, w) |
| { |
| ipa_reference_vars_info_t w_ri = get_reference_vars_info (w); |
| w_ri->global = *node_g; |
| } |
| |
| cycle_nodes.release (); |
| } |
| |
| if (dump_file) |
| { |
| for (i = 0; i < order_pos; i++) |
| { |
| unsigned x; |
| struct cgraph_node *w; |
| |
| node = order[i]; |
| if (node->alias || !opt_for_fn (node->decl, flag_ipa_reference)) |
| continue; |
| |
| fprintf (dump_file, "\nFunction name:%s:", node->dump_asm_name ()); |
| |
| ipa_reference_vars_info_t node_info = get_reference_vars_info (node); |
| ipa_reference_global_vars_info_t node_g = &node_info->global; |
| |
| vec<cgraph_node *> cycle_nodes = ipa_get_nodes_in_cycle (node); |
| FOR_EACH_VEC_ELT (cycle_nodes, x, w) |
| { |
| ipa_reference_vars_info_t w_ri = get_reference_vars_info (w); |
| ipa_reference_local_vars_info_t w_l = &w_ri->local; |
| if (w != node) |
| fprintf (dump_file, "\n next cycle: %s ", w->dump_asm_name ()); |
| fprintf (dump_file, "\n locals read: "); |
| dump_static_vars_set_to_file (dump_file, w_l->statics_read); |
| fprintf (dump_file, "\n locals written: "); |
| dump_static_vars_set_to_file (dump_file, w_l->statics_written); |
| } |
| cycle_nodes.release (); |
| |
| fprintf (dump_file, "\n globals read: "); |
| dump_static_vars_set_to_file (dump_file, node_g->statics_read); |
| fprintf (dump_file, "\n globals written: "); |
| dump_static_vars_set_to_file (dump_file, node_g->statics_written); |
| fprintf (dump_file, "\n"); |
| } |
| } |
| |
| if (ipa_ref_opt_sum_summaries == NULL) |
| { |
| ipa_ref_opt_sum_summaries = new ipa_ref_opt_summary_t (symtab); |
| ipa_ref_opt_sum_summaries->disable_insertion_hook (); |
| } |
| |
| /* Cleanup. */ |
| FOR_EACH_DEFINED_FUNCTION (node) |
| { |
| ipa_reference_vars_info_t node_info; |
| ipa_reference_global_vars_info_t node_g; |
| |
| /* No need to produce summaries for inline clones. */ |
| if (node->inlined_to) |
| continue; |
| |
| node_info = get_reference_vars_info (node); |
| if (!node->alias && opt_for_fn (node->decl, flag_ipa_reference)) |
| { |
| node_g = &node_info->global; |
| bool read_all = |
| (node_g->statics_read == all_module_statics |
| || bitmap_equal_p (node_g->statics_read, all_module_statics)); |
| bool written_all = |
| (node_g->statics_written == all_module_statics |
| || bitmap_equal_p (node_g->statics_written, |
| all_module_statics)); |
| |
| /* There is no need to produce summary if we collected nothing |
| useful. */ |
| if (read_all && written_all) |
| continue; |
| |
| ipa_reference_optimization_summary_d *opt |
| = ipa_ref_opt_sum_summaries->get_create (node); |
| |
| /* Create the complimentary sets. */ |
| |
| if (bitmap_empty_p (node_g->statics_read)) |
| opt->statics_read = no_module_statics; |
| else if (read_all) |
| opt->statics_read = all_module_statics; |
| else |
| { |
| opt->statics_read |
| = BITMAP_ALLOC (&optimization_summary_obstack); |
| bitmap_copy (opt->statics_read, node_g->statics_read); |
| } |
| |
| if (bitmap_empty_p (node_g->statics_written)) |
| opt->statics_written = no_module_statics; |
| else if (written_all) |
| opt->statics_written = all_module_statics; |
| else |
| { |
| opt->statics_written |
| = BITMAP_ALLOC (&optimization_summary_obstack); |
| bitmap_copy (opt->statics_written, node_g->statics_written); |
| } |
| } |
| } |
| |
| ipa_free_postorder_info (); |
| free (order); |
| |
| bitmap_obstack_release (&local_info_obstack); |
| |
| if (ipa_ref_var_info_summaries != NULL) |
| { |
| delete ipa_ref_var_info_summaries; |
| ipa_ref_var_info_summaries = NULL; |
| } |
| |
| if (dump_file) |
| { |
| vec_free (reference_vars_to_consider); |
| reference_vars_to_consider = NULL; |
| } |
| else |
| gcc_checking_assert (!reference_vars_to_consider); |
| return remove_p ? TODO_remove_functions : 0; |
| } |
| |
| /* Return true if we need to write summary of NODE. */ |
| |
| static bool |
| write_node_summary_p (struct cgraph_node *node, |
| lto_symtab_encoder_t encoder, |
| bitmap ltrans_statics) |
| { |
| ipa_reference_optimization_summary_t info; |
| |
| /* See if we have (non-empty) info. */ |
| if (!node->definition || node->inlined_to) |
| return false; |
| info = get_reference_optimization_summary (node); |
| if (!info) |
| return false; |
| |
| /* See if we want to encode it. |
| Encode also referenced functions since constant folding might turn it into |
| a direct call. |
| |
| In future we might also want to include summaries of functions references |
| by initializers of constant variables references in current unit. */ |
| if (!reachable_from_this_partition_p (node, encoder) |
| && !referenced_from_this_partition_p (node, encoder)) |
| return false; |
| |
| /* See if the info has non-empty intersections with vars we want to |
| encode. */ |
| bitmap_iterator bi; |
| unsigned int i; |
| EXECUTE_IF_AND_COMPL_IN_BITMAP (ltrans_statics, info->statics_read, 0, |
| i, bi) |
| return true; |
| EXECUTE_IF_AND_COMPL_IN_BITMAP (ltrans_statics, info->statics_written, 0, |
| i, bi) |
| return true; |
| return false; |
| } |
| |
| /* Stream out BITS<RANS_STATICS as list of decls to OB. |
| LTRANS_STATICS_BITCOUNT specify number of bits in LTRANS_STATICS |
| or -1. When it is positive, just output -1 when |
| BITS<RANS_STATICS == BITS<RANS_STATICS. */ |
| |
| static void |
| stream_out_bitmap (struct lto_simple_output_block *ob, |
| bitmap bits, bitmap ltrans_statics, |
| int ltrans_statics_bitcount) |
| { |
| int count = 0; |
| unsigned int index; |
| bitmap_iterator bi; |
| if (bits == all_module_statics) |
| { |
| streamer_write_hwi_stream (ob->main_stream, -1); |
| return; |
| } |
| EXECUTE_IF_AND_IN_BITMAP (bits, ltrans_statics, 0, index, bi) |
| count ++; |
| if (count == ltrans_statics_bitcount) |
| { |
| streamer_write_hwi_stream (ob->main_stream, -1); |
| return; |
| } |
| streamer_write_hwi_stream (ob->main_stream, count); |
| if (!count) |
| return; |
| EXECUTE_IF_AND_IN_BITMAP (bits, ltrans_statics, 0, index, bi) |
| { |
| tree decl = (*reference_vars_to_consider) [index]; |
| lto_output_var_decl_ref (ob->decl_state, ob->main_stream, decl); |
| } |
| } |
| |
| /* Serialize the ipa info for lto. */ |
| |
| static void |
| ipa_reference_write_optimization_summary (void) |
| { |
| struct lto_simple_output_block *ob |
| = lto_create_simple_output_block (LTO_section_ipa_reference); |
| unsigned int count = 0; |
| int ltrans_statics_bitcount = 0; |
| lto_symtab_encoder_t encoder = ob->decl_state->symtab_node_encoder; |
| auto_bitmap ltrans_statics; |
| int i; |
| |
| gcc_checking_assert (!reference_vars_to_consider); |
| vec_alloc (reference_vars_to_consider, ipa_reference_vars_uids); |
| reference_vars_to_consider->safe_grow (ipa_reference_vars_uids, true); |
| |
| /* See what variables we are interested in. */ |
| for (i = 0; i < lto_symtab_encoder_size (encoder); i++) |
| { |
| symtab_node *snode = lto_symtab_encoder_deref (encoder, i); |
| varpool_node *vnode = dyn_cast <varpool_node *> (snode); |
| int id; |
| |
| if (vnode |
| && (id = ipa_reference_var_uid (vnode->decl)) != -1 |
| && referenced_from_this_partition_p (vnode, encoder)) |
| { |
| tree decl = vnode->decl; |
| bitmap_set_bit (ltrans_statics, id); |
| (*reference_vars_to_consider)[id] = decl; |
| ltrans_statics_bitcount ++; |
| } |
| } |
| |
| |
| if (ltrans_statics_bitcount) |
| for (i = 0; i < lto_symtab_encoder_size (encoder); i++) |
| { |
| symtab_node *snode = lto_symtab_encoder_deref (encoder, i); |
| cgraph_node *cnode = dyn_cast <cgraph_node *> (snode); |
| if (cnode && write_node_summary_p (cnode, encoder, ltrans_statics)) |
| count++; |
| } |
| |
| streamer_write_uhwi_stream (ob->main_stream, count); |
| if (count) |
| stream_out_bitmap (ob, ltrans_statics, ltrans_statics, |
| -1); |
| |
| /* Process all of the functions. */ |
| if (ltrans_statics_bitcount) |
| for (i = 0; i < lto_symtab_encoder_size (encoder); i++) |
| { |
| symtab_node *snode = lto_symtab_encoder_deref (encoder, i); |
| cgraph_node *cnode = dyn_cast <cgraph_node *> (snode); |
| if (cnode && write_node_summary_p (cnode, encoder, ltrans_statics)) |
| { |
| ipa_reference_optimization_summary_t info; |
| int node_ref; |
| |
| info = get_reference_optimization_summary (cnode); |
| node_ref = lto_symtab_encoder_encode (encoder, snode); |
| streamer_write_uhwi_stream (ob->main_stream, node_ref); |
| |
| stream_out_bitmap (ob, info->statics_read, ltrans_statics, |
| ltrans_statics_bitcount); |
| stream_out_bitmap (ob, info->statics_written, ltrans_statics, |
| ltrans_statics_bitcount); |
| } |
| } |
| lto_destroy_simple_output_block (ob); |
| vec_free (reference_vars_to_consider); |
| reference_vars_to_consider = NULL; |
| } |
| |
| /* Deserialize the ipa info for lto. */ |
| |
| static void |
| ipa_reference_read_optimization_summary (void) |
| { |
| struct lto_file_decl_data ** file_data_vec |
| = lto_get_file_decl_data (); |
| struct lto_file_decl_data * file_data; |
| unsigned int j = 0; |
| bitmap_obstack_initialize (&optimization_summary_obstack); |
| |
| gcc_checking_assert (ipa_ref_opt_sum_summaries == NULL); |
| ipa_ref_opt_sum_summaries = new ipa_ref_opt_summary_t (symtab); |
| ipa_ref_opt_sum_summaries->disable_insertion_hook (); |
| ipa_reference_vars_map = new reference_vars_map_t(257); |
| varpool_node_hooks |
| = symtab->add_varpool_removal_hook (varpool_removal_hook, NULL); |
| ipa_reference_vars_uids = 0; |
| |
| all_module_statics = BITMAP_ALLOC (&optimization_summary_obstack); |
| no_module_statics = BITMAP_ALLOC (&optimization_summary_obstack); |
| |
| while ((file_data = file_data_vec[j++])) |
| { |
| const char *data; |
| size_t len; |
| class lto_input_block *ib |
| = lto_create_simple_input_block (file_data, |
| LTO_section_ipa_reference, |
| &data, &len); |
| if (ib) |
| { |
| unsigned int i; |
| unsigned int f_count = streamer_read_uhwi (ib); |
| int b_count; |
| if (!f_count) |
| continue; |
| b_count = streamer_read_hwi (ib); |
| if (dump_file) |
| fprintf (dump_file, "all module statics:"); |
| for (i = 0; i < (unsigned int)b_count; i++) |
| { |
| tree v_decl = lto_input_var_decl_ref (ib, file_data); |
| bool existed; |
| bitmap_set_bit (all_module_statics, |
| ipa_reference_var_get_or_insert_uid |
| (v_decl, &existed)); |
| gcc_checking_assert (!existed); |
| if (dump_file) |
| fprintf (dump_file, " %s", fndecl_name (v_decl)); |
| } |
| |
| for (i = 0; i < f_count; i++) |
| { |
| unsigned int j, index; |
| struct cgraph_node *node; |
| int v_count; |
| lto_symtab_encoder_t encoder; |
| |
| index = streamer_read_uhwi (ib); |
| encoder = file_data->symtab_node_encoder; |
| node = dyn_cast<cgraph_node *> (lto_symtab_encoder_deref |
| (encoder, index)); |
| |
| ipa_reference_optimization_summary_d *info |
| = ipa_ref_opt_sum_summaries->get_create (node); |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "\nFunction name:%s:\n static read:", |
| node->dump_asm_name ()); |
| |
| /* Set the statics read. */ |
| v_count = streamer_read_hwi (ib); |
| if (v_count == -1) |
| { |
| info->statics_read = all_module_statics; |
| if (dump_file) |
| fprintf (dump_file, " all module statics"); |
| } |
| else if (v_count == 0) |
| info->statics_read = no_module_statics; |
| else |
| { |
| info->statics_read = BITMAP_ALLOC |
| (&optimization_summary_obstack); |
| for (j = 0; j < (unsigned int)v_count; j++) |
| { |
| tree v_decl = lto_input_var_decl_ref (ib, file_data); |
| bitmap_set_bit (info->statics_read, |
| ipa_reference_var_uid (v_decl)); |
| if (dump_file) |
| fprintf (dump_file, " %s", fndecl_name (v_decl)); |
| } |
| } |
| |
| if (dump_file) |
| fprintf (dump_file, |
| "\n static written:"); |
| /* Set the statics written. */ |
| v_count = streamer_read_hwi (ib); |
| if (v_count == -1) |
| { |
| info->statics_written = all_module_statics; |
| if (dump_file) |
| fprintf (dump_file, " all module statics"); |
| } |
| else if (v_count == 0) |
| info->statics_written = no_module_statics; |
| else |
| { |
| info->statics_written = BITMAP_ALLOC |
| (&optimization_summary_obstack); |
| for (j = 0; j < (unsigned int)v_count; j++) |
| { |
| tree v_decl = lto_input_var_decl_ref (ib, file_data); |
| bitmap_set_bit (info->statics_written, |
| ipa_reference_var_uid (v_decl)); |
| if (dump_file) |
| fprintf (dump_file, " %s", fndecl_name (v_decl)); |
| } |
| } |
| if (dump_file) |
| fprintf (dump_file, "\n"); |
| } |
| |
| lto_destroy_simple_input_block (file_data, |
| LTO_section_ipa_reference, |
| ib, data, len); |
| } |
| else |
| /* Fatal error here. We do not want to support compiling ltrans units |
| with different version of compiler or different flags than |
| the WPA unit, so this should never happen. */ |
| fatal_error (input_location, |
| "ipa reference summary is missing in ltrans unit"); |
| } |
| } |
| |
| namespace { |
| |
| const pass_data pass_data_ipa_reference = |
| { |
| IPA_PASS, /* type */ |
| "static-var", /* name */ |
| OPTGROUP_NONE, /* optinfo_flags */ |
| TV_IPA_REFERENCE, /* tv_id */ |
| 0, /* properties_required */ |
| 0, /* properties_provided */ |
| 0, /* properties_destroyed */ |
| 0, /* todo_flags_start */ |
| 0, /* todo_flags_finish */ |
| }; |
| |
| class pass_ipa_reference : public ipa_opt_pass_d |
| { |
| public: |
| pass_ipa_reference (gcc::context *ctxt) |
| : ipa_opt_pass_d (pass_data_ipa_reference, ctxt, |
| NULL, /* generate_summary */ |
| NULL, /* write_summary */ |
| NULL, /* read_summary */ |
| ipa_reference_write_optimization_summary, /* |
| write_optimization_summary */ |
| ipa_reference_read_optimization_summary, /* |
| read_optimization_summary */ |
| NULL, /* stmt_fixup */ |
| 0, /* function_transform_todo_flags_start */ |
| NULL, /* function_transform */ |
| NULL) /* variable_transform */ |
| {} |
| |
| /* opt_pass methods: */ |
| bool gate (function *) final override |
| { |
| return ((in_lto_p || flag_ipa_reference) |
| /* Don't bother doing anything if the program has errors. */ |
| && !seen_error ()); |
| } |
| |
| unsigned int execute (function *) final override { return propagate (); } |
| |
| }; // class pass_ipa_reference |
| |
| } // anon namespace |
| |
| ipa_opt_pass_d * |
| make_pass_ipa_reference (gcc::context *ctxt) |
| { |
| return new pass_ipa_reference (ctxt); |
| } |
| |
| /* Reset all state within ipa-reference.cc so that we can rerun the compiler |
| within the same process. For use by toplev::finalize. */ |
| |
| void |
| ipa_reference_cc_finalize (void) |
| { |
| if (ipa_ref_opt_sum_summaries != NULL) |
| { |
| delete ipa_ref_opt_sum_summaries; |
| ipa_ref_opt_sum_summaries = NULL; |
| delete ipa_reference_vars_map; |
| ipa_reference_vars_map = NULL; |
| symtab->remove_varpool_removal_hook (varpool_node_hooks); |
| } |
| |
| if (ipa_init_p) |
| { |
| bitmap_obstack_release (&optimization_summary_obstack); |
| ipa_init_p = false; |
| } |
| } |