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Diffstat (limited to 'gcc/ipa-icf.c')
| -rw-r--r-- | gcc/ipa-icf.c | 2371 |
1 files changed, 2371 insertions, 0 deletions
diff --git a/gcc/ipa-icf.c b/gcc/ipa-icf.c new file mode 100644 index 00000000000..4e73849f1b0 --- /dev/null +++ b/gcc/ipa-icf.c @@ -0,0 +1,2371 @@ +/* Interprocedural Identical Code Folding pass + Copyright (C) 2014 Free Software Foundation, Inc. + + Contributed by Jan Hubicka <hubicka@ucw.cz> and Martin Liska <mliska@suse.cz> + +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/>. */ + +/* Interprocedural Identical Code Folding for functions and + read-only variables. + + The goal of this transformation is to discover functions and read-only + variables which do have exactly the same semantics. + + In case of functions, + we could either create a virtual clone or do a simple function wrapper + that will call equivalent function. If the function is just locally visible, + all function calls can be redirected. For read-only variables, we create + aliases if possible. + + Optimization pass arranges as follows: + 1) All functions and read-only variables are visited and internal + data structure, either sem_function or sem_variables is created. + 2) For every symbol from the previous step, VAR_DECL and FUNCTION_DECL are + saved and matched to corresponding sem_items. + 3) These declaration are ignored for equality check and are solved + by Value Numbering algorithm published by Alpert, Zadeck in 1992. + 4) We compute hash value for each symbol. + 5) Congruence classes are created based on hash value. If hash value are + equal, equals function is called and symbols are deeply compared. + We must prove that all SSA names, declarations and other items + correspond. + 6) Value Numbering is executed for these classes. At the end of the process + all symbol members in remaining classes can be merged. + 7) Merge operation creates alias in case of read-only variables. For + callgraph node, we must decide if we can redirect local calls, + create an alias or a thunk. + +*/ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tree.h" +#include "basic-block.h" +#include "tree-ssa-alias.h" +#include "internal-fn.h" +#include "gimple-expr.h" +#include "is-a.h" +#include "gimple.h" +#include "expr.h" +#include "gimple-iterator.h" +#include "gimple-ssa.h" +#include "tree-cfg.h" +#include "tree-phinodes.h" +#include "stringpool.h" +#include "tree-ssanames.h" +#include "tree-dfa.h" +#include "tree-pass.h" +#include "gimple-pretty-print.h" +#include "ipa-inline.h" +#include "cfgloop.h" +#include "except.h" +#include "hash-table.h" +#include "coverage.h" +#include "attribs.h" +#include "print-tree.h" +#include "lto-streamer.h" +#include "data-streamer.h" +#include "ipa-utils.h" +#include <list> +#include "ipa-icf-gimple.h" +#include "ipa-icf.h" + +using namespace ipa_icf_gimple; + +namespace ipa_icf { +/* Constructor for key value pair, where _ITEM is key and _INDEX is a target. */ + +sem_usage_pair::sem_usage_pair (sem_item *_item, unsigned int _index): + item (_item), index (_index) +{ +} + +/* Semantic item constructor for a node of _TYPE, where STACK is used + for bitmap memory allocation. */ + +sem_item::sem_item (sem_item_type _type, + bitmap_obstack *stack): type(_type), hash(0) +{ + setup (stack); +} + +/* Semantic item constructor for a node of _TYPE, where STACK is used + for bitmap memory allocation. The item is based on symtab node _NODE + with computed _HASH. */ + +sem_item::sem_item (sem_item_type _type, symtab_node *_node, + hashval_t _hash, bitmap_obstack *stack): type(_type), + node (_node), hash (_hash) +{ + decl = node->decl; + setup (stack); +} + +/* Add reference to a semantic TARGET. */ + +void +sem_item::add_reference (sem_item *target) +{ + refs.safe_push (target); + unsigned index = refs.length (); + target->usages.safe_push (new sem_usage_pair(this, index)); + bitmap_set_bit (target->usage_index_bitmap, index); + refs_set.add (target->node); +} + +/* Initialize internal data structures. Bitmap STACK is used for + bitmap memory allocation process. */ + +void +sem_item::setup (bitmap_obstack *stack) +{ + gcc_checking_assert (node); + + refs.create (0); + tree_refs.create (0); + usages.create (0); + usage_index_bitmap = BITMAP_ALLOC (stack); +} + +sem_item::~sem_item () +{ + for (unsigned i = 0; i < usages.length (); i++) + delete usages[i]; + + refs.release (); + tree_refs.release (); + usages.release (); + + BITMAP_FREE (usage_index_bitmap); +} + +/* Dump function for debugging purpose. */ + +DEBUG_FUNCTION void +sem_item::dump (void) +{ + if (dump_file) + { + fprintf (dump_file, "[%s] %s (%u) (tree:%p)\n", type == FUNC ? "func" : "var", + name(), node->order, (void *) node->decl); + fprintf (dump_file, " hash: %u\n", get_hash ()); + fprintf (dump_file, " references: "); + + for (unsigned i = 0; i < refs.length (); i++) + fprintf (dump_file, "%s%s ", refs[i]->name (), + i < refs.length() - 1 ? "," : ""); + + fprintf (dump_file, "\n"); + } +} + +/* Semantic function constructor that uses STACK as bitmap memory stack. */ + +sem_function::sem_function (bitmap_obstack *stack): sem_item (FUNC, stack), + m_checker (NULL), m_compared_func (NULL) +{ + arg_types.create (0); + bb_sizes.create (0); + bb_sorted.create (0); +} + +/* Constructor based on callgraph node _NODE with computed hash _HASH. + Bitmap STACK is used for memory allocation. */ +sem_function::sem_function (cgraph_node *node, hashval_t hash, + bitmap_obstack *stack): + sem_item (FUNC, node, hash, stack), + m_checker (NULL), m_compared_func (NULL) +{ + arg_types.create (0); + bb_sizes.create (0); + bb_sorted.create (0); +} + +sem_function::~sem_function () +{ + for (unsigned i = 0; i < bb_sorted.length (); i++) + free (bb_sorted[i]); + + arg_types.release (); + bb_sizes.release (); + bb_sorted.release (); +} + +/* Calculates hash value based on a BASIC_BLOCK. */ + +hashval_t +sem_function::get_bb_hash (const sem_bb *basic_block) +{ + inchash::hash hstate; + + hstate.add_int (basic_block->nondbg_stmt_count); + hstate.add_int (basic_block->edge_count); + + return hstate.end (); +} + +/* References independent hash function. */ + +hashval_t +sem_function::get_hash (void) +{ + if(!hash) + { + inchash::hash hstate; + hstate.add_int (177454); /* Random number for function type. */ + + hstate.add_int (arg_count); + hstate.add_int (cfg_checksum); + hstate.add_int (gcode_hash); + + for (unsigned i = 0; i < bb_sorted.length (); i++) + hstate.merge_hash (get_bb_hash (bb_sorted[i])); + + for (unsigned i = 0; i < bb_sizes.length (); i++) + hstate.add_int (bb_sizes[i]); + + hash = hstate.end (); + } + + return hash; +} + +/* For a given symbol table nodes N1 and N2, we check that FUNCTION_DECLs + point to a same function. Comparison can be skipped if IGNORED_NODES + contains these nodes. */ + +bool +sem_function::compare_cgraph_references (hash_map <symtab_node *, sem_item *> + &ignored_nodes, + symtab_node *n1, symtab_node *n2) +{ + if (n1 == n2 || (ignored_nodes.get (n1) && ignored_nodes.get (n2))) + return true; + + /* TODO: add more precise comparison for weakrefs, etc. */ + + return return_false_with_msg ("different references"); +} + +/* If cgraph edges E1 and E2 are indirect calls, verify that + ECF flags are the same. */ + +bool sem_function::compare_edge_flags (cgraph_edge *e1, cgraph_edge *e2) +{ + if (e1->indirect_info && e2->indirect_info) + { + int e1_flags = e1->indirect_info->ecf_flags; + int e2_flags = e2->indirect_info->ecf_flags; + + if (e1_flags != e2_flags) + return return_false_with_msg ("ICF flags are different"); + } + else if (e1->indirect_info || e2->indirect_info) + return false; + + return true; +} + +/* Fast equality function based on knowledge known in WPA. */ + +bool +sem_function::equals_wpa (sem_item *item, + hash_map <symtab_node *, sem_item *> &ignored_nodes) +{ + gcc_assert (item->type == FUNC); + + m_compared_func = static_cast<sem_function *> (item); + + if (arg_types.length () != m_compared_func->arg_types.length ()) + return return_false_with_msg ("different number of arguments"); + + /* Checking types of arguments. */ + for (unsigned i = 0; i < arg_types.length (); i++) + { + /* This guard is here for function pointer with attributes (pr59927.c). */ + if (!arg_types[i] || !m_compared_func->arg_types[i]) + return return_false_with_msg ("NULL argument type"); + + /* Polymorphic comparison is executed just for non-leaf functions. */ + bool is_not_leaf = get_node ()->callees != NULL; + + if (!func_checker::compatible_types_p (arg_types[i], + m_compared_func->arg_types[i], + is_not_leaf, i == 0)) + return return_false_with_msg ("argument type is different"); + } + + /* Result type checking. */ + if (!func_checker::compatible_types_p (result_type, + m_compared_func->result_type)) + return return_false_with_msg ("result types are different"); + + if (node->num_references () != item->node->num_references ()) + return return_false_with_msg ("different number of references"); + + ipa_ref *ref = NULL, *ref2 = NULL; + for (unsigned i = 0; node->iterate_reference (i, ref); i++) + { + item->node->iterate_reference (i, ref2); + + if (!compare_cgraph_references (ignored_nodes, ref->referred, ref2->referred)) + return false; + } + + cgraph_edge *e1 = dyn_cast <cgraph_node *> (node)->callees; + cgraph_edge *e2 = dyn_cast <cgraph_node *> (item->node)->callees; + + while (e1 && e2) + { + if (!compare_cgraph_references (ignored_nodes, e1->callee, e2->callee)) + return false; + + e1 = e1->next_callee; + e2 = e2->next_callee; + } + + if (e1 || e2) + return return_false_with_msg ("different number of edges"); + + return true; +} + +/* Returns true if the item equals to ITEM given as argument. */ + +bool +sem_function::equals (sem_item *item, + hash_map <symtab_node *, sem_item *> &ignored_nodes) +{ + gcc_assert (item->type == FUNC); + bool eq = equals_private (item, ignored_nodes); + + if (m_checker != NULL) + { + delete m_checker; + m_checker = NULL; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Equals called for:%s:%s (%u:%u) (%s:%s) with result: %s\n\n", + name(), item->name (), node->order, item->node->order, asm_name (), + item->asm_name (), eq ? "true" : "false"); + + return eq; +} + +/* Processes function equality comparison. */ + +bool +sem_function::equals_private (sem_item *item, + hash_map <symtab_node *, sem_item *> &ignored_nodes) +{ + if (item->type != FUNC) + return false; + + basic_block bb1, bb2; + edge e1, e2; + edge_iterator ei1, ei2; + int *bb_dict = NULL; + bool result = true; + tree arg1, arg2; + + m_compared_func = static_cast<sem_function *> (item); + + gcc_assert (decl != item->decl); + + if (bb_sorted.length () != m_compared_func->bb_sorted.length () + || edge_count != m_compared_func->edge_count + || cfg_checksum != m_compared_func->cfg_checksum) + return return_false (); + + if (!equals_wpa (item, ignored_nodes)) + return false; + + /* Checking function arguments. */ + tree decl1 = DECL_ATTRIBUTES (decl); + tree decl2 = DECL_ATTRIBUTES (m_compared_func->decl); + + m_checker = new func_checker (decl, m_compared_func->decl, + compare_polymorphic_p (), + false, + &refs_set, + &m_compared_func->refs_set); + while (decl1) + { + if (decl2 == NULL) + return return_false (); + + if (get_attribute_name (decl1) != get_attribute_name (decl2)) + return return_false (); + + tree attr_value1 = TREE_VALUE (decl1); + tree attr_value2 = TREE_VALUE (decl2); + + if (attr_value1 && attr_value2) + { + bool ret = m_checker->compare_operand (TREE_VALUE (attr_value1), + TREE_VALUE (attr_value2)); + if (!ret) + return return_false_with_msg ("attribute values are different"); + } + else if (!attr_value1 && !attr_value2) + {} + else + return return_false (); + + decl1 = TREE_CHAIN (decl1); + decl2 = TREE_CHAIN (decl2); + } + + if (decl1 != decl2) + return return_false(); + + + for (arg1 = DECL_ARGUMENTS (decl), + arg2 = DECL_ARGUMENTS (m_compared_func->decl); + arg1; arg1 = DECL_CHAIN (arg1), arg2 = DECL_CHAIN (arg2)) + if (!m_checker->compare_decl (arg1, arg2)) + return return_false (); + + /* Fill-up label dictionary. */ + for (unsigned i = 0; i < bb_sorted.length (); ++i) + { + m_checker->parse_labels (bb_sorted[i]); + m_checker->parse_labels (m_compared_func->bb_sorted[i]); + } + + /* Checking all basic blocks. */ + for (unsigned i = 0; i < bb_sorted.length (); ++i) + if(!m_checker->compare_bb (bb_sorted[i], m_compared_func->bb_sorted[i])) + return return_false(); + + dump_message ("All BBs are equal\n"); + + /* Basic block edges check. */ + for (unsigned i = 0; i < bb_sorted.length (); ++i) + { + bb_dict = XNEWVEC (int, bb_sorted.length () + 2); + memset (bb_dict, -1, (bb_sorted.length () + 2) * sizeof (int)); + + bb1 = bb_sorted[i]->bb; + bb2 = m_compared_func->bb_sorted[i]->bb; + + ei2 = ei_start (bb2->preds); + + for (ei1 = ei_start (bb1->preds); ei_cond (ei1, &e1); ei_next (&ei1)) + { + ei_cond (ei2, &e2); + + if (e1->flags != e2->flags) + return return_false_with_msg ("flags comparison returns false"); + + if (!bb_dict_test (bb_dict, e1->src->index, e2->src->index)) + return return_false_with_msg ("edge comparison returns false"); + + if (!bb_dict_test (bb_dict, e1->dest->index, e2->dest->index)) + return return_false_with_msg ("BB comparison returns false"); + + if (!m_checker->compare_edge (e1, e2)) + return return_false_with_msg ("edge comparison returns false"); + + ei_next (&ei2); + } + } + + /* Basic block PHI nodes comparison. */ + for (unsigned i = 0; i < bb_sorted.length (); i++) + if (!compare_phi_node (bb_sorted[i]->bb, m_compared_func->bb_sorted[i]->bb)) + return return_false_with_msg ("PHI node comparison returns false"); + + return result; +} + +/* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can + be applied. */ +bool +sem_function::merge (sem_item *alias_item) +{ + gcc_assert (alias_item->type == FUNC); + + sem_function *alias_func = static_cast<sem_function *> (alias_item); + + cgraph_node *original = get_node (); + cgraph_node *local_original = original; + cgraph_node *alias = alias_func->get_node (); + bool original_address_matters; + bool alias_address_matters; + + bool create_thunk = false; + bool create_alias = false; + bool redirect_callers = false; + bool original_discardable = false; + + /* Do not attempt to mix functions from different user sections; + we do not know what user intends with those. */ + if (((DECL_SECTION_NAME (original->decl) && !original->implicit_section) + || (DECL_SECTION_NAME (alias->decl) && !alias->implicit_section)) + && DECL_SECTION_NAME (original->decl) != DECL_SECTION_NAME (alias->decl)) + { + if (dump_file) + fprintf (dump_file, + "Not unifying; original and alias are in different sections.\n\n"); + return false; + } + + /* See if original is in a section that can be discarded if the main + symbol is not used. */ + if (DECL_EXTERNAL (original->decl)) + original_discardable = true; + if (original->resolution == LDPR_PREEMPTED_REG + || original->resolution == LDPR_PREEMPTED_IR) + original_discardable = true; + if (original->can_be_discarded_p ()) + original_discardable = true; + + /* See if original and/or alias address can be compared for equality. */ + original_address_matters + = (!DECL_VIRTUAL_P (original->decl) + && (original->externally_visible + || original->address_taken_from_non_vtable_p ())); + alias_address_matters + = (!DECL_VIRTUAL_P (alias->decl) + && (alias->externally_visible + || alias->address_taken_from_non_vtable_p ())); + + /* If alias and original can be compared for address equality, we need + to create a thunk. Also we can not create extra aliases into discardable + section (or we risk link failures when section is discarded). */ + if ((original_address_matters + && alias_address_matters) + || original_discardable) + { + create_thunk = !stdarg_p (TREE_TYPE (alias->decl)); + create_alias = false; + /* When both alias and original are not overwritable, we can save + the extra thunk wrapper for direct calls. */ + redirect_callers + = (!original_discardable + && alias->get_availability () > AVAIL_INTERPOSABLE + && original->get_availability () > AVAIL_INTERPOSABLE); + } + else + { + create_alias = true; + create_thunk = false; + redirect_callers = false; + } + + if (create_alias && DECL_COMDAT_GROUP (alias->decl)) + { + create_alias = false; + create_thunk = true; + } + + /* We want thunk to always jump to the local function body + unless the body is comdat and may be optimized out. */ + if ((create_thunk || redirect_callers) + && (!original_discardable + || (DECL_COMDAT_GROUP (original->decl) + && (DECL_COMDAT_GROUP (original->decl) + == DECL_COMDAT_GROUP (alias->decl))))) + local_original + = dyn_cast <cgraph_node *> (original->noninterposable_alias ()); + + if (redirect_callers) + { + /* If alias is non-overwritable then + all direct calls are safe to be redirected to the original. */ + bool redirected = false; + while (alias->callers) + { + cgraph_edge *e = alias->callers; + e->redirect_callee (local_original); + push_cfun (DECL_STRUCT_FUNCTION (e->caller->decl)); + + if (e->call_stmt) + e->redirect_call_stmt_to_callee (); + + pop_cfun (); + redirected = true; + } + + alias->icf_merged = true; + + /* The alias function is removed if symbol address + does not matter. */ + if (!alias_address_matters) + alias->remove (); + + if (dump_file && redirected) + fprintf (dump_file, "Callgraph local calls have been redirected.\n\n"); + } + /* If the condtion above is not met, we are lucky and can turn the + function into real alias. */ + else if (create_alias) + { + alias->icf_merged = true; + + /* Remove the function's body. */ + ipa_merge_profiles (original, alias); + alias->release_body (true); + alias->reset (); + + /* Create the alias. */ + cgraph_node::create_alias (alias_func->decl, decl); + alias->resolve_alias (original); + + if (dump_file) + fprintf (dump_file, "Callgraph alias has been created.\n\n"); + } + else if (create_thunk) + { + if (DECL_COMDAT_GROUP (alias->decl)) + { + if (dump_file) + fprintf (dump_file, "Callgraph thunk cannot be created because of COMDAT\n"); + + return 0; + } + + alias->icf_merged = true; + ipa_merge_profiles (local_original, alias); + alias->create_wrapper (local_original); + + if (dump_file) + fprintf (dump_file, "Callgraph thunk has been created.\n\n"); + } + else if (dump_file) + fprintf (dump_file, "Callgraph merge operation cannot be performed.\n\n"); + + return true; +} + +/* Semantic item initialization function. */ + +void +sem_function::init (void) +{ + if (in_lto_p) + get_node ()->get_body (); + + tree fndecl = node->decl; + function *func = DECL_STRUCT_FUNCTION (fndecl); + + gcc_assert (func); + gcc_assert (SSANAMES (func)); + + ssa_names_size = SSANAMES (func)->length (); + node = node; + + decl = fndecl; + region_tree = func->eh->region_tree; + + /* iterating all function arguments. */ + arg_count = count_formal_params (fndecl); + + edge_count = n_edges_for_fn (func); + cfg_checksum = coverage_compute_cfg_checksum (func); + + inchash::hash hstate; + + basic_block bb; + FOR_EACH_BB_FN (bb, func) + { + unsigned nondbg_stmt_count = 0; + + edge e; + for (edge_iterator ei = ei_start (bb->preds); ei_cond (ei, &e); ei_next (&ei)) + cfg_checksum = iterative_hash_host_wide_int (e->flags, + cfg_checksum); + + for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); + gsi_next (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + + if (gimple_code (stmt) != GIMPLE_DEBUG) + { + hash_stmt (&hstate, stmt); + nondbg_stmt_count++; + } + } + + gcode_hash = hstate.end (); + bb_sizes.safe_push (nondbg_stmt_count); + + /* Inserting basic block to hash table. */ + sem_bb *semantic_bb = new sem_bb (bb, nondbg_stmt_count, + EDGE_COUNT (bb->preds) + EDGE_COUNT (bb->succs)); + + bb_sorted.safe_push (semantic_bb); + } + + parse_tree_args (); +} + +/* Improve accumulated hash for HSTATE based on a gimple statement STMT. */ + +void +sem_function::hash_stmt (inchash::hash *hstate, gimple stmt) +{ + enum gimple_code code = gimple_code (stmt); + + hstate->add_int (code); + + if (code == GIMPLE_CALL) + { + /* Checking of argument. */ + for (unsigned i = 0; i < gimple_call_num_args (stmt); ++i) + { + tree argument = gimple_call_arg (stmt, i); + + switch (TREE_CODE (argument)) + { + case INTEGER_CST: + if (tree_fits_shwi_p (argument)) + hstate->add_wide_int (tree_to_shwi (argument)); + else if (tree_fits_uhwi_p (argument)) + hstate->add_wide_int (tree_to_uhwi (argument)); + break; + case REAL_CST: + REAL_VALUE_TYPE c; + HOST_WIDE_INT n; + + c = TREE_REAL_CST (argument); + n = real_to_integer (&c); + + hstate->add_wide_int (n); + break; + case ADDR_EXPR: + { + tree addr_operand = TREE_OPERAND (argument, 0); + + if (TREE_CODE (addr_operand) == STRING_CST) + hstate->add (TREE_STRING_POINTER (addr_operand), + TREE_STRING_LENGTH (addr_operand)); + break; + } + default: + break; + } + } + } +} + + +/* Return true if polymorphic comparison must be processed. */ + +bool +sem_function::compare_polymorphic_p (void) +{ + return get_node ()->callees != NULL + || m_compared_func->get_node ()->callees != NULL; +} + +/* For a given call graph NODE, the function constructs new + semantic function item. */ + +sem_function * +sem_function::parse (cgraph_node *node, bitmap_obstack *stack) +{ + tree fndecl = node->decl; + function *func = DECL_STRUCT_FUNCTION (fndecl); + + /* TODO: add support for thunks and aliases. */ + + if (!func || !node->has_gimple_body_p ()) + return NULL; + + if (lookup_attribute_by_prefix ("omp ", DECL_ATTRIBUTES (node->decl)) != NULL) + return NULL; + + sem_function *f = new sem_function (node, 0, stack); + + f->init (); + + return f; +} + +/* Parses function arguments and result type. */ + +void +sem_function::parse_tree_args (void) +{ + tree result; + + if (arg_types.exists ()) + arg_types.release (); + + arg_types.create (4); + tree fnargs = DECL_ARGUMENTS (decl); + + for (tree parm = fnargs; parm; parm = DECL_CHAIN (parm)) + arg_types.safe_push (DECL_ARG_TYPE (parm)); + + /* Function result type. */ + result = DECL_RESULT (decl); + result_type = result ? TREE_TYPE (result) : NULL; + + /* During WPA, we can get arguments by following method. */ + if (!fnargs) + { + tree type = TYPE_ARG_TYPES (TREE_TYPE (decl)); + for (tree parm = type; parm; parm = TREE_CHAIN (parm)) + arg_types.safe_push (TYPE_CANONICAL (TREE_VALUE (parm))); + + result_type = TREE_TYPE (TREE_TYPE (decl)); + } +} + +/* For given basic blocks BB1 and BB2 (from functions FUNC1 and FUNC), + return true if phi nodes are semantically equivalent in these blocks . */ + +bool +sem_function::compare_phi_node (basic_block bb1, basic_block bb2) +{ + gimple_stmt_iterator si1, si2; + gimple phi1, phi2; + unsigned size1, size2, i; + tree t1, t2; + edge e1, e2; + + gcc_assert (bb1 != NULL); + gcc_assert (bb2 != NULL); + + si2 = gsi_start_phis (bb2); + for (si1 = gsi_start_phis (bb1); !gsi_end_p (si1); + gsi_next (&si1)) + { + gsi_next_nonvirtual_phi (&si1); + gsi_next_nonvirtual_phi (&si2); + + if (gsi_end_p (si1) && gsi_end_p (si2)) + break; + + if (gsi_end_p (si1) || gsi_end_p (si2)) + return return_false(); + + phi1 = gsi_stmt (si1); + phi2 = gsi_stmt (si2); + + size1 = gimple_phi_num_args (phi1); + size2 = gimple_phi_num_args (phi2); + + if (size1 != size2) + return return_false (); + + for (i = 0; i < size1; ++i) + { + t1 = gimple_phi_arg (phi1, i)->def; + t2 = gimple_phi_arg (phi2, i)->def; + + if (!m_checker->compare_operand (t1, t2)) + return return_false (); + + e1 = gimple_phi_arg_edge (phi1, i); + e2 = gimple_phi_arg_edge (phi2, i); + + if (!m_checker->compare_edge (e1, e2)) + return return_false (); + } + + gsi_next (&si2); + } + + return true; +} + +/* Returns true if tree T can be compared as a handled component. */ + +bool +sem_function::icf_handled_component_p (tree t) +{ + tree_code tc = TREE_CODE (t); + + return ((handled_component_p (t)) + || tc == ADDR_EXPR || tc == MEM_REF || tc == REALPART_EXPR + || tc == IMAGPART_EXPR || tc == OBJ_TYPE_REF); +} + +/* Basic blocks dictionary BB_DICT returns true if SOURCE index BB + corresponds to TARGET. */ + +bool +sem_function::bb_dict_test (int* bb_dict, int source, int target) +{ + if (bb_dict[source] == -1) + { + bb_dict[source] = target; + return true; + } + else + return bb_dict[source] == target; +} + +/* Iterates all tree types in T1 and T2 and returns true if all types + are compatible. If COMPARE_POLYMORPHIC is set to true, + more strict comparison is executed. */ + +bool +sem_function::compare_type_list (tree t1, tree t2, bool compare_polymorphic) +{ + tree tv1, tv2; + tree_code tc1, tc2; + + if (!t1 && !t2) + return true; + + while (t1 != NULL && t2 != NULL) + { + tv1 = TREE_VALUE (t1); + tv2 = TREE_VALUE (t2); + + tc1 = TREE_CODE (tv1); + tc2 = TREE_CODE (tv2); + + if (tc1 == NOP_EXPR && tc2 == NOP_EXPR) + {} + else if (tc1 == NOP_EXPR || tc2 == NOP_EXPR) + return false; + else if (!func_checker::compatible_types_p (tv1, tv2, compare_polymorphic)) + return false; + + t1 = TREE_CHAIN (t1); + t2 = TREE_CHAIN (t2); + } + + return !(t1 || t2); +} + + +/* Semantic variable constructor that uses STACK as bitmap memory stack. */ + +sem_variable::sem_variable (bitmap_obstack *stack): sem_item (VAR, stack) +{ +} + +/* Constructor based on varpool node _NODE with computed hash _HASH. + Bitmap STACK is used for memory allocation. */ + +sem_variable::sem_variable (varpool_node *node, hashval_t _hash, + bitmap_obstack *stack): sem_item(VAR, + node, _hash, stack) +{ + gcc_checking_assert (node); + gcc_checking_assert (get_node ()); +} + +/* Returns true if the item equals to ITEM given as argument. */ + +bool +sem_variable::equals (sem_item *item, + hash_map <symtab_node *, sem_item *> & ARG_UNUSED (ignored_nodes)) +{ + gcc_assert (item->type == VAR); + + sem_variable *v = static_cast<sem_variable *>(item); + + if (!ctor || !v->ctor) + return return_false_with_msg ("ctor is missing for semantic variable"); + + return sem_variable::equals (ctor, v->ctor); +} + +/* Compares trees T1 and T2 for semantic equality. */ + +bool +sem_variable::equals (tree t1, tree t2) +{ + tree_code tc1 = TREE_CODE (t1); + tree_code tc2 = TREE_CODE (t2); + + if (tc1 != tc2) + return false; + + switch (tc1) + { + case CONSTRUCTOR: + { + unsigned len1 = vec_safe_length (CONSTRUCTOR_ELTS (t1)); + unsigned len2 = vec_safe_length (CONSTRUCTOR_ELTS (t2)); + + if (len1 != len2) + return false; + + for (unsigned i = 0; i < len1; i++) + if (!sem_variable::equals (CONSTRUCTOR_ELT (t1, i)->value, + CONSTRUCTOR_ELT (t2, i)->value) + || CONSTRUCTOR_ELT (t1, i)->index != CONSTRUCTOR_ELT (t2, i)->index) + return false; + + return true; + } + case MEM_REF: + { + tree x1 = TREE_OPERAND (t1, 0); + tree x2 = TREE_OPERAND (t2, 0); + tree y1 = TREE_OPERAND (t1, 1); + tree y2 = TREE_OPERAND (t2, 1); + + if (!func_checker::compatible_types_p (TREE_TYPE (x1), TREE_TYPE (x2), + true)) + return return_false (); + + /* Type of the offset on MEM_REF does not matter. */ + return sem_variable::equals (x1, x2) + && wi::to_offset (y1) == wi::to_offset (y2); + } + case NOP_EXPR: + case ADDR_EXPR: + { + tree op1 = TREE_OPERAND (t1, 0); + tree op2 = TREE_OPERAND (t2, 0); + return sem_variable::equals (op1, op2); + } + case FUNCTION_DECL: + case VAR_DECL: + case FIELD_DECL: + case LABEL_DECL: + return t1 == t2; + case INTEGER_CST: + return func_checker::compatible_types_p (TREE_TYPE (t1), TREE_TYPE (t2), + true) + && wi::to_offset (t1) == wi::to_offset (t2); + case STRING_CST: + case REAL_CST: + case COMPLEX_CST: + return operand_equal_p (t1, t2, OEP_ONLY_CONST); + case COMPONENT_REF: + case ARRAY_REF: + case POINTER_PLUS_EXPR: + { + tree x1 = TREE_OPERAND (t1, 0); + tree x2 = TREE_OPERAND (t2, 0); + tree y1 = TREE_OPERAND (t1, 1); + tree y2 = TREE_OPERAND (t2, 1); + + return sem_variable::equals (x1, x2) && sem_variable::equals (y1, y2); + } + case ERROR_MARK: + return return_false_with_msg ("ERROR_MARK"); + default: + return return_false_with_msg ("Unknown TREE code reached"); + } +} + +/* Parser function that visits a varpool NODE. */ + +sem_variable * +sem_variable::parse (varpool_node *node, bitmap_obstack *stack) +{ + tree decl = node->decl; + + bool readonly = TYPE_P (decl) ? TYPE_READONLY (decl) : TREE_READONLY (decl); + bool can_handle = readonly && (DECL_VIRTUAL_P (decl) + || !TREE_ADDRESSABLE (decl)); + + if (!can_handle) + return NULL; + + tree ctor = ctor_for_folding (decl); + if (!ctor) + return NULL; + + sem_variable *v = new sem_variable (node, 0, stack); + + v->init (); + + return v; +} + +/* References independent hash function. */ + +hashval_t +sem_variable::get_hash (void) +{ + if (hash) + return hash; + + inchash::hash hstate; + + hstate.add_int (456346417); + hstate.add_int (TREE_CODE (ctor)); + + if (TREE_CODE (ctor) == CONSTRUCTOR) + { + unsigned length = vec_safe_length (CONSTRUCTOR_ELTS (ctor)); + hstate.add_int (length); + } + + hash = hstate.end (); + + return hash; +} + +/* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can + be applied. */ + +bool +sem_variable::merge (sem_item *alias_item) +{ + gcc_assert (alias_item->type == VAR); + + sem_variable *alias_var = static_cast<sem_variable *> (alias_item); + + varpool_node *original = get_node (); + varpool_node *alias = alias_var->get_node (); + bool original_discardable = false; + + /* See if original is in a section that can be discarded if the main + symbol is not used. */ + if (DECL_EXTERNAL (original->decl)) + original_discardable = true; + if (original->resolution == LDPR_PREEMPTED_REG + || original->resolution == LDPR_PREEMPTED_IR) + original_discardable = true; + if (original->can_be_discarded_p ()) + original_discardable = true; + + gcc_assert (!TREE_ASM_WRITTEN (alias->decl)); + + if (original_discardable || DECL_EXTERNAL (alias_var->decl) || + !compare_sections (alias_var)) + { + if (dump_file) + fprintf (dump_file, "Varpool alias cannot be created\n\n"); + + return false; + } + else + { + // alias cycle creation check + varpool_node *n = original; + + while (n->alias) + { + n = n->get_alias_target (); + if (n == alias) + { + if (dump_file) + fprintf (dump_file, "Varpool alias cannot be created (alias cycle).\n\n"); + + return false; + } + } + + alias->analyzed = false; + + DECL_INITIAL (alias->decl) = NULL; + alias->remove_all_references (); + + varpool_node::create_alias (alias_var->decl, decl); + alias->resolve_alias (original); + + if (dump_file) + fprintf (dump_file, "Varpool alias has been created.\n\n"); + + return true; + } +} + +bool +sem_variable::compare_sections (sem_variable *alias) +{ + const char *source = node->get_section (); + const char *target = alias->node->get_section(); + + if (source == NULL && target == NULL) + return true; + else if(!source || !target) + return false; + else + return strcmp (source, target) == 0; +} + +/* Dump symbol to FILE. */ + +void +sem_variable::dump_to_file (FILE *file) +{ + gcc_assert (file); + + print_node (file, "", decl, 0); + fprintf (file, "\n\n"); +} + +/* Iterates though a constructor and identifies tree references + we are interested in semantic function equality. */ + +void +sem_variable::parse_tree_refs (tree t) +{ + switch (TREE_CODE (t)) + { + case CONSTRUCTOR: + { + unsigned length = vec_safe_length (CONSTRUCTOR_ELTS (t)); + + for (unsigned i = 0; i < length; i++) + parse_tree_refs(CONSTRUCTOR_ELT (t, i)->value); + + break; + } + case NOP_EXPR: + case ADDR_EXPR: + { + tree op = TREE_OPERAND (t, 0); + parse_tree_refs (op); + break; + } + case FUNCTION_DECL: + { + tree_refs.safe_push (t); + break; + } + default: + break; + } +} + +unsigned int sem_item_optimizer::class_id = 0; + +sem_item_optimizer::sem_item_optimizer (): worklist (0), m_classes (0), + m_classes_count (0), m_cgraph_node_hooks (NULL), m_varpool_node_hooks (NULL) +{ + m_items.create (0); + bitmap_obstack_initialize (&m_bmstack); +} + +sem_item_optimizer::~sem_item_optimizer () +{ + for (unsigned int i = 0; i < m_items.length (); i++) + delete m_items[i]; + + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + { + for (unsigned int i = 0; i < (*it)->classes.length (); i++) + delete (*it)->classes[i]; + + (*it)->classes.release (); + } + + m_items.release (); + + bitmap_obstack_release (&m_bmstack); +} + +/* Write IPA ICF summary for symbols. */ + +void +sem_item_optimizer::write_summary (void) +{ + unsigned int count = 0; + + output_block *ob = create_output_block (LTO_section_ipa_icf); + lto_symtab_encoder_t encoder = ob->decl_state->symtab_node_encoder; + ob->symbol = NULL; + + /* Calculate number of symbols to be serialized. */ + for (lto_symtab_encoder_iterator lsei = lsei_start_in_partition (encoder); + !lsei_end_p (lsei); + lsei_next_in_partition (&lsei)) + { + symtab_node *node = lsei_node (lsei); + + if (m_symtab_node_map.get (node)) + count++; + } + + streamer_write_uhwi (ob, count); + + /* Process all of the symbols. */ + for (lto_symtab_encoder_iterator lsei = lsei_start_in_partition (encoder); + !lsei_end_p (lsei); + lsei_next_in_partition (&lsei)) + { + symtab_node *node = lsei_node (lsei); + + sem_item **item = m_symtab_node_map.get (node); + + if (item && *item) + { + int node_ref = lto_symtab_encoder_encode (encoder, node); + streamer_write_uhwi_stream (ob->main_stream, node_ref); + + streamer_write_uhwi (ob, (*item)->get_hash ()); + } + } + + streamer_write_char_stream (ob->main_stream, 0); + produce_asm (ob, NULL); + destroy_output_block (ob); +} + +/* Reads a section from LTO stream file FILE_DATA. Input block for DATA + contains LEN bytes. */ + +void +sem_item_optimizer::read_section (lto_file_decl_data *file_data, + const char *data, size_t len) +{ + const lto_function_header *header = + (const lto_function_header *) data; + const int cfg_offset = sizeof (lto_function_header); + const int main_offset = cfg_offset + header->cfg_size; + const int string_offset = main_offset + header->main_size; + data_in *data_in; + unsigned int i; + unsigned int count; + + lto_input_block ib_main ((const char *) data + main_offset, 0, + header->main_size); + + data_in = + lto_data_in_create (file_data, (const char *) data + string_offset, + header->string_size, vNULL); + + count = streamer_read_uhwi (&ib_main); + + for (i = 0; i < count; i++) + { + unsigned int index; + symtab_node *node; + lto_symtab_encoder_t encoder; + + index = streamer_read_uhwi (&ib_main); + encoder = file_data->symtab_node_encoder; + node = lto_symtab_encoder_deref (encoder, index); + + hashval_t hash = streamer_read_uhwi (&ib_main); + + gcc_assert (node->definition); + + if (dump_file) + fprintf (dump_file, "Symbol added:%s (tree: %p, uid:%u)\n", node->asm_name (), + (void *) node->decl, node->order); + + if (is_a<cgraph_node *> (node)) + { + cgraph_node *cnode = dyn_cast <cgraph_node *> (node); + + m_items.safe_push (new sem_function (cnode, hash, &m_bmstack)); + } + else + { + varpool_node *vnode = dyn_cast <varpool_node *> (node); + + m_items.safe_push (new sem_variable (vnode, hash, &m_bmstack)); + } + } + + lto_free_section_data (file_data, LTO_section_ipa_icf, NULL, data, + len); + lto_data_in_delete (data_in); +} + +/* Read IPA IPA ICF summary for symbols. */ + +void +sem_item_optimizer::read_summary (void) +{ + lto_file_decl_data **file_data_vec = lto_get_file_decl_data (); + lto_file_decl_data *file_data; + unsigned int j = 0; + + while ((file_data = file_data_vec[j++])) + { + size_t len; + const char *data = lto_get_section_data (file_data, + LTO_section_ipa_icf, NULL, &len); + + if (data) + read_section (file_data, data, len); + } +} + +/* Register callgraph and varpool hooks. */ + +void +sem_item_optimizer::register_hooks (void) +{ + m_cgraph_node_hooks = symtab->add_cgraph_removal_hook + (&sem_item_optimizer::cgraph_removal_hook, this); + + m_varpool_node_hooks = symtab->add_varpool_removal_hook + (&sem_item_optimizer::varpool_removal_hook, this); +} + +/* Unregister callgraph and varpool hooks. */ + +void +sem_item_optimizer::unregister_hooks (void) +{ + if (m_cgraph_node_hooks) + symtab->remove_cgraph_removal_hook (m_cgraph_node_hooks); + + if (m_varpool_node_hooks) + symtab->remove_varpool_removal_hook (m_varpool_node_hooks); +} + +/* Adds a CLS to hashtable associated by hash value. */ + +void +sem_item_optimizer::add_class (congruence_class *cls) +{ + gcc_assert (cls->members.length ()); + + congruence_class_group *group = get_group_by_hash ( + cls->members[0]->get_hash (), + cls->members[0]->type); + group->classes.safe_push (cls); +} + +/* Gets a congruence class group based on given HASH value and TYPE. */ + +congruence_class_group * +sem_item_optimizer::get_group_by_hash (hashval_t hash, sem_item_type type) +{ + congruence_class_group *item = XNEW (congruence_class_group); + item->hash = hash; + item->type = type; + + congruence_class_group **slot = m_classes.find_slot (item, INSERT); + + if (*slot) + free (item); + else + { + item->classes.create (1); + *slot = item; + } + + return *slot; +} + +/* Callgraph removal hook called for a NODE with a custom DATA. */ + +void +sem_item_optimizer::cgraph_removal_hook (cgraph_node *node, void *data) +{ + sem_item_optimizer *optimizer = (sem_item_optimizer *) data; + optimizer->remove_symtab_node (node); +} + +/* Varpool removal hook called for a NODE with a custom DATA. */ + +void +sem_item_optimizer::varpool_removal_hook (varpool_node *node, void *data) +{ + sem_item_optimizer *optimizer = (sem_item_optimizer *) data; + optimizer->remove_symtab_node (node); +} + +/* Remove symtab NODE triggered by symtab removal hooks. */ + +void +sem_item_optimizer::remove_symtab_node (symtab_node *node) +{ + gcc_assert (!m_classes.elements()); + + m_removed_items_set.add (node); +} + +void +sem_item_optimizer::remove_item (sem_item *item) +{ + if (m_symtab_node_map.get (item->node)) + m_symtab_node_map.remove (item->node); + delete item; +} + +/* Removes all callgraph and varpool nodes that are marked by symtab + as deleted. */ + +void +sem_item_optimizer::filter_removed_items (void) +{ + auto_vec <sem_item *> filtered; + + for (unsigned int i = 0; i < m_items.length(); i++) + { + sem_item *item = m_items[i]; + + if (!flag_ipa_icf_functions && item->type == FUNC) + { + remove_item (item); + continue; + } + + if (!flag_ipa_icf_variables && item->type == VAR) + { + remove_item (item); + continue; + } + + bool no_body_function = false; + + if (item->type == FUNC) + { + cgraph_node *cnode = static_cast <sem_function *>(item)->get_node (); + + no_body_function = in_lto_p && (cnode->alias || cnode->body_removed); + } + + if(!m_removed_items_set.contains (m_items[i]->node) + && !no_body_function) + { + if (item->type == VAR || (!DECL_CXX_CONSTRUCTOR_P (item->decl) + && !DECL_CXX_DESTRUCTOR_P (item->decl))) + { + filtered.safe_push (m_items[i]); + continue; + } + } + + remove_item (item); + } + + /* Clean-up of released semantic items. */ + + m_items.release (); + for (unsigned int i = 0; i < filtered.length(); i++) + m_items.safe_push (filtered[i]); +} + +/* Optimizer entry point. */ + +void +sem_item_optimizer::execute (void) +{ + filter_removed_items (); + build_hash_based_classes (); + + if (dump_file) + fprintf (dump_file, "Dump after hash based groups\n"); + dump_cong_classes (); + + for (unsigned int i = 0; i < m_items.length(); i++) + m_items[i]->init_wpa (); + + build_graph (); + + subdivide_classes_by_equality (true); + + if (dump_file) + fprintf (dump_file, "Dump after WPA based types groups\n"); + + dump_cong_classes (); + + process_cong_reduction (); + verify_classes (); + + if (dump_file) + fprintf (dump_file, "Dump after callgraph-based congruence reduction\n"); + + dump_cong_classes (); + + parse_nonsingleton_classes (); + subdivide_classes_by_equality (); + + if (dump_file) + fprintf (dump_file, "Dump after full equality comparison of groups\n"); + + dump_cong_classes (); + + unsigned int prev_class_count = m_classes_count; + + process_cong_reduction (); + dump_cong_classes (); + verify_classes (); + merge_classes (prev_class_count); + + if (dump_file && (dump_flags & TDF_DETAILS)) + symtab_node::dump_table (dump_file); +} + +/* Function responsible for visiting all potential functions and + read-only variables that can be merged. */ + +void +sem_item_optimizer::parse_funcs_and_vars (void) +{ + cgraph_node *cnode; + + if (flag_ipa_icf_functions) + FOR_EACH_DEFINED_FUNCTION (cnode) + { + sem_function *f = sem_function::parse (cnode, &m_bmstack); + if (f) + { + m_items.safe_push (f); + m_symtab_node_map.put (cnode, f); + + if (dump_file) + fprintf (dump_file, "Parsed function:%s\n", f->asm_name ()); + + if (dump_file && (dump_flags & TDF_DETAILS)) + f->dump_to_file (dump_file); + } + else if (dump_file) + fprintf (dump_file, "Not parsed function:%s\n", cnode->asm_name ()); + } + + varpool_node *vnode; + + if (flag_ipa_icf_variables) + FOR_EACH_DEFINED_VARIABLE (vnode) + { + sem_variable *v = sem_variable::parse (vnode, &m_bmstack); + + if (v) + { + m_items.safe_push (v); + m_symtab_node_map.put (vnode, v); + } + } +} + +/* Makes pairing between a congruence class CLS and semantic ITEM. */ + +void +sem_item_optimizer::add_item_to_class (congruence_class *cls, sem_item *item) +{ + item->index_in_class = cls->members.length (); + cls->members.safe_push (item); + item->cls = cls; +} + +/* Congruence classes are built by hash value. */ + +void +sem_item_optimizer::build_hash_based_classes (void) +{ + for (unsigned i = 0; i < m_items.length (); i++) + { + sem_item *item = m_items[i]; + + congruence_class_group *group = get_group_by_hash (item->get_hash (), + item->type); + + if (!group->classes.length ()) + { + m_classes_count++; + group->classes.safe_push (new congruence_class (class_id++)); + } + + add_item_to_class (group->classes[0], item); + } +} + +/* Build references according to call graph. */ + +void +sem_item_optimizer::build_graph (void) +{ + for (unsigned i = 0; i < m_items.length (); i++) + { + sem_item *item = m_items[i]; + m_symtab_node_map.put (item->node, item); + } + + for (unsigned i = 0; i < m_items.length (); i++) + { + sem_item *item = m_items[i]; + + if (item->type == FUNC) + { + cgraph_node *cnode = dyn_cast <cgraph_node *> (item->node); + + cgraph_edge *e = cnode->callees; + while (e) + { + sem_item **slot = m_symtab_node_map.get (e->callee); + if (slot) + item->add_reference (*slot); + + e = e->next_callee; + } + } + + ipa_ref *ref = NULL; + for (unsigned i = 0; item->node->iterate_reference (i, ref); i++) + { + sem_item **slot = m_symtab_node_map.get (ref->referred); + if (slot) + item->add_reference (*slot); + } + } +} + +/* Semantic items in classes having more than one element and initialized. + In case of WPA, we load function body. */ + +void +sem_item_optimizer::parse_nonsingleton_classes (void) +{ + unsigned int init_called_count = 0; + + for (unsigned i = 0; i < m_items.length (); i++) + if (m_items[i]->cls->members.length () > 1) + { + m_items[i]->init (); + init_called_count++; + } + + if (dump_file) + fprintf (dump_file, "Init called for %u items (%.2f%%).\n", init_called_count, + 100.0f * init_called_count / m_items.length ()); +} + +/* Equality function for semantic items is used to subdivide existing + classes. If IN_WPA, fast equality function is invoked. */ + +void +sem_item_optimizer::subdivide_classes_by_equality (bool in_wpa) +{ + for (hash_table <congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + { + unsigned int class_count = (*it)->classes.length (); + + for (unsigned i = 0; i < class_count; i++) + { + congruence_class *c = (*it)->classes [i]; + + if (c->members.length() > 1) + { + auto_vec <sem_item *> new_vector; + + sem_item *first = c->members[0]; + new_vector.safe_push (first); + + unsigned class_split_first = (*it)->classes.length (); + + for (unsigned j = 1; j < c->members.length (); j++) + { + sem_item *item = c->members[j]; + + bool equals = in_wpa ? first->equals_wpa (item, + m_symtab_node_map) : first->equals (item, m_symtab_node_map); + + if (equals) + new_vector.safe_push (item); + else + { + bool integrated = false; + + for (unsigned k = class_split_first; k < (*it)->classes.length (); k++) + { + sem_item *x = (*it)->classes[k]->members[0]; + bool equals = in_wpa ? x->equals_wpa (item, + m_symtab_node_map) : x->equals (item, m_symtab_node_map); + + if (equals) + { + integrated = true; + add_item_to_class ((*it)->classes[k], item); + + break; + } + } + + if (!integrated) + { + congruence_class *c = new congruence_class (class_id++); + m_classes_count++; + add_item_to_class (c, item); + + (*it)->classes.safe_push (c); + } + } + } + + // we replace newly created new_vector for the class we've just splitted + c->members.release (); + c->members.create (new_vector.length ()); + + for (unsigned int j = 0; j < new_vector.length (); j++) + add_item_to_class (c, new_vector[j]); + } + } + } + + verify_classes (); +} + +/* Verify congruence classes if checking is enabled. */ + +void +sem_item_optimizer::verify_classes (void) +{ +#if ENABLE_CHECKING + for (hash_table <congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + { + for (unsigned int i = 0; i < (*it)->classes.length (); i++) + { + congruence_class *cls = (*it)->classes[i]; + + gcc_checking_assert (cls); + gcc_checking_assert (cls->members.length () > 0); + + for (unsigned int j = 0; j < cls->members.length (); j++) + { + sem_item *item = cls->members[j]; + + gcc_checking_assert (item); + gcc_checking_assert (item->cls == cls); + + for (unsigned k = 0; k < item->usages.length (); k++) + { + sem_usage_pair *usage = item->usages[k]; + gcc_checking_assert (usage->item->index_in_class < + usage->item->cls->members.length ()); + } + } + } + } +#endif +} + +/* Disposes split map traverse function. CLS_PTR is pointer to congruence + class, BSLOT is bitmap slot we want to release. DATA is mandatory, + but unused argument. */ + +bool +sem_item_optimizer::release_split_map (congruence_class * const &, + bitmap const &b, traverse_split_pair *) +{ + bitmap bmp = b; + + BITMAP_FREE (bmp); + + return true; +} + +/* Process split operation for a class given as pointer CLS_PTR, + where bitmap B splits congruence class members. DATA is used + as argument of split pair. */ + +bool +sem_item_optimizer::traverse_congruence_split (congruence_class * const &cls, + bitmap const &b, traverse_split_pair *pair) +{ + sem_item_optimizer *optimizer = pair->optimizer; + const congruence_class *splitter_cls = pair->cls; + + /* If counted bits are greater than zero and less than the number of members + a group will be splitted. */ + unsigned popcount = bitmap_count_bits (b); + + if (popcount > 0 && popcount < cls->members.length ()) + { + congruence_class* newclasses[2] = { new congruence_class (class_id++), new congruence_class (class_id++) }; + + for (unsigned int i = 0; i < cls->members.length (); i++) + { + int target = bitmap_bit_p (b, i); + congruence_class *tc = newclasses[target]; + + add_item_to_class (tc, cls->members[i]); + } + +#ifdef ENABLE_CHECKING + for (unsigned int i = 0; i < 2; i++) + gcc_checking_assert (newclasses[i]->members.length ()); +#endif + + if (splitter_cls == cls) + optimizer->splitter_class_removed = true; + + /* Remove old class from worklist if presented. */ + bool in_worklist = cls->in_worklist; + + if (in_worklist) + cls->in_worklist = false; + + congruence_class_group g; + g.hash = cls->members[0]->get_hash (); + g.type = cls->members[0]->type; + + congruence_class_group *slot = optimizer->m_classes.find(&g); + + for (unsigned int i = 0; i < slot->classes.length (); i++) + if (slot->classes[i] == cls) + { + slot->classes.ordered_remove (i); + break; + } + + /* New class will be inserted and integrated to work list. */ + for (unsigned int i = 0; i < 2; i++) + optimizer->add_class (newclasses[i]); + + /* Two classes replace one, so that increment just by one. */ + optimizer->m_classes_count++; + + /* If OLD class was presented in the worklist, we remove the class + and replace it will both newly created classes. */ + if (in_worklist) + for (unsigned int i = 0; i < 2; i++) + optimizer->worklist_push (newclasses[i]); + else /* Just smaller class is inserted. */ + { + unsigned int smaller_index = newclasses[0]->members.length () < + newclasses[1]->members.length () ? + 0 : 1; + optimizer->worklist_push (newclasses[smaller_index]); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, " congruence class splitted:\n"); + cls->dump (dump_file, 4); + + fprintf (dump_file, " newly created groups:\n"); + for (unsigned int i = 0; i < 2; i++) + newclasses[i]->dump (dump_file, 4); + } + + /* Release class if not presented in work list. */ + if (!in_worklist) + delete cls; + } + + + return true; +} + +/* Tests if a class CLS used as INDEXth splits any congruence classes. + Bitmap stack BMSTACK is used for bitmap allocation. */ + +void +sem_item_optimizer::do_congruence_step_for_index (congruence_class *cls, + unsigned int index) +{ + hash_map <congruence_class *, bitmap> split_map; + + for (unsigned int i = 0; i < cls->members.length (); i++) + { + sem_item *item = cls->members[i]; + + /* Iterate all usages that have INDEX as usage of the item. */ + for (unsigned int j = 0; j < item->usages.length (); j++) + { + sem_usage_pair *usage = item->usages[j]; + + if (usage->index != index) + continue; + + bitmap *slot = split_map.get (usage->item->cls); + bitmap b; + + if(!slot) + { + b = BITMAP_ALLOC (&m_bmstack); + split_map.put (usage->item->cls, b); + } + else + b = *slot; + +#if ENABLE_CHECKING + gcc_checking_assert (usage->item->cls); + gcc_checking_assert (usage->item->index_in_class < + usage->item->cls->members.length ()); +#endif + + bitmap_set_bit (b, usage->item->index_in_class); + } + } + + traverse_split_pair pair; + pair.optimizer = this; + pair.cls = cls; + + splitter_class_removed = false; + split_map.traverse + <traverse_split_pair *, sem_item_optimizer::traverse_congruence_split> (&pair); + + /* Bitmap clean-up. */ + split_map.traverse + <traverse_split_pair *, sem_item_optimizer::release_split_map> (NULL); +} + +/* Every usage of a congruence class CLS is a candidate that can split the + collection of classes. Bitmap stack BMSTACK is used for bitmap + allocation. */ + +void +sem_item_optimizer::do_congruence_step (congruence_class *cls) +{ + bitmap_iterator bi; + unsigned int i; + + bitmap usage = BITMAP_ALLOC (&m_bmstack); + + for (unsigned int i = 0; i < cls->members.length (); i++) + bitmap_ior_into (usage, cls->members[i]->usage_index_bitmap); + + EXECUTE_IF_SET_IN_BITMAP (usage, 0, i, bi) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, " processing congruece step for class: %u, index: %u\n", + cls->id, i); + + do_congruence_step_for_index (cls, i); + + if (splitter_class_removed) + break; + } + + BITMAP_FREE (usage); +} + +/* Adds a newly created congruence class CLS to worklist. */ + +void +sem_item_optimizer::worklist_push (congruence_class *cls) +{ + /* Return if the class CLS is already presented in work list. */ + if (cls->in_worklist) + return; + + cls->in_worklist = true; + worklist.push_back (cls); +} + +/* Pops a class from worklist. */ + +congruence_class * +sem_item_optimizer::worklist_pop (void) +{ + congruence_class *cls; + + while (!worklist.empty ()) + { + cls = worklist.front (); + worklist.pop_front (); + if (cls->in_worklist) + { + cls->in_worklist = false; + + return cls; + } + else + { + /* Work list item was already intended to be removed. + The only reason for doing it is to split a class. + Thus, the class CLS is deleted. */ + delete cls; + } + } + + return NULL; +} + +/* Iterative congruence reduction function. */ + +void +sem_item_optimizer::process_cong_reduction (void) +{ + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + for (unsigned i = 0; i < (*it)->classes.length (); i++) + if ((*it)->classes[i]->is_class_used ()) + worklist_push ((*it)->classes[i]); + + if (dump_file) + fprintf (dump_file, "Worklist has been filled with: %lu\n", + worklist.size ()); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Congruence class reduction\n"); + + congruence_class *cls; + while ((cls = worklist_pop ()) != NULL) + do_congruence_step (cls); +} + +/* Debug function prints all informations about congruence classes. */ + +void +sem_item_optimizer::dump_cong_classes (void) +{ + if (!dump_file) + return; + + fprintf (dump_file, + "Congruence classes: %u (unique hash values: %lu), with total: %u items\n", + m_classes_count, m_classes.elements(), m_items.length ()); + + /* Histogram calculation. */ + unsigned int max_index = 0; + unsigned int* histogram = XCNEWVEC (unsigned int, m_items.length () + 1); + + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + + for (unsigned i = 0; i < (*it)->classes.length (); i++) + { + unsigned int c = (*it)->classes[i]->members.length (); + histogram[c]++; + + if (c > max_index) + max_index = c; + } + + fprintf (dump_file, + "Class size histogram [num of members]: number of classe number of classess\n"); + + for (unsigned int i = 0; i <= max_index; i++) + if (histogram[i]) + fprintf (dump_file, "[%u]: %u classes\n", i, histogram[i]); + + fprintf (dump_file, "\n\n"); + + + if (dump_flags & TDF_DETAILS) + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + { + fprintf (dump_file, " group: with %u classes:\n", (*it)->classes.length ()); + + for (unsigned i = 0; i < (*it)->classes.length (); i++) + { + (*it)->classes[i]->dump (dump_file, 4); + + if(i < (*it)->classes.length () - 1) + fprintf (dump_file, " "); + } + } + + free (histogram); +} + +/* After reduction is done, we can declare all items in a group + to be equal. PREV_CLASS_COUNT is start number of classes + before reduction. */ + +void +sem_item_optimizer::merge_classes (unsigned int prev_class_count) +{ + unsigned int item_count = m_items.length (); + unsigned int class_count = m_classes_count; + unsigned int equal_items = item_count - class_count; + + unsigned int non_singular_classes_count = 0; + unsigned int non_singular_classes_sum = 0; + + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + for (unsigned int i = 0; i < (*it)->classes.length (); i++) + { + congruence_class *c = (*it)->classes[i]; + if (c->members.length () > 1) + { + non_singular_classes_count++; + non_singular_classes_sum += c->members.length (); + } + } + + if (dump_file) + { + fprintf (dump_file, "\nItem count: %u\n", item_count); + fprintf (dump_file, "Congruent classes before: %u, after: %u\n", + prev_class_count, class_count); + fprintf (dump_file, "Average class size before: %.2f, after: %.2f\n", + 1.0f * item_count / prev_class_count, + 1.0f * item_count / class_count); + fprintf (dump_file, "Average non-singular class size: %.2f, count: %u\n", + 1.0f * non_singular_classes_sum / non_singular_classes_count, + non_singular_classes_count); + fprintf (dump_file, "Equal symbols: %u\n", equal_items); + fprintf (dump_file, "Fraction of visited symbols: %.2f%%\n\n", + 100.0f * equal_items / item_count); + } + + for (hash_table<congruence_class_group_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + for (unsigned int i = 0; i < (*it)->classes.length (); i++) + { + congruence_class *c = (*it)->classes[i]; + + if (c->members.length () == 1) + continue; + + gcc_assert (c->members.length ()); + + sem_item *source = c->members[0]; + + for (unsigned int j = 1; j < c->members.length (); j++) + { + sem_item *alias = c->members[j]; + source->equals (alias, m_symtab_node_map); + + if (dump_file) + { + fprintf (dump_file, "Semantic equality hit:%s->%s\n", + source->name (), alias->name ()); + fprintf (dump_file, "Assembler symbol names:%s->%s\n", + source->asm_name (), alias->asm_name ()); + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + source->dump_to_file (dump_file); + alias->dump_to_file (dump_file); + } + + source->merge (alias); + } + } +} + +/* Dump function prints all class members to a FILE with an INDENT. */ + +void +congruence_class::dump (FILE *file, unsigned int indent) const +{ + FPRINTF_SPACES (file, indent, "class with id: %u, hash: %u, items: %u\n", + id, members[0]->get_hash (), members.length ()); + + FPUTS_SPACES (file, indent + 2, ""); + for (unsigned i = 0; i < members.length (); i++) + fprintf (file, "%s(%p/%u) ", members[i]->asm_name (), (void *) members[i]->decl, + members[i]->node->order); + + fprintf (file, "\n"); +} + +/* Returns true if there's a member that is used from another group. */ + +bool +congruence_class::is_class_used (void) +{ + for (unsigned int i = 0; i < members.length (); i++) + if (members[i]->usages.length ()) + return true; + + return false; +} + +/* Initialization and computation of symtab node hash, there data + are propagated later on. */ + +static sem_item_optimizer *optimizer = NULL; + +/* Generate pass summary for IPA ICF pass. */ + +static void +ipa_icf_generate_summary (void) +{ + if (!optimizer) + optimizer = new sem_item_optimizer (); + + optimizer->parse_funcs_and_vars (); +} + +/* Write pass summary for IPA ICF pass. */ + +static void +ipa_icf_write_summary (void) +{ + gcc_assert (optimizer); + + optimizer->write_summary (); +} + +/* Read pass summary for IPA ICF pass. */ + +static void +ipa_icf_read_summary (void) +{ + if (!optimizer) + optimizer = new sem_item_optimizer (); + + optimizer->read_summary (); + optimizer->register_hooks (); +} + +/* Semantic equality exection function. */ + +static unsigned int +ipa_icf_driver (void) +{ + gcc_assert (optimizer); + + optimizer->execute (); + optimizer->unregister_hooks (); + + delete optimizer; + + return 0; +} + +const pass_data pass_data_ipa_icf = +{ + IPA_PASS, /* type */ + "icf", /* name */ + OPTGROUP_IPA, /* optinfo_flags */ + TV_IPA_ICF, /* tv_id */ + 0, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + 0, /* todo_flags_finish */ +}; + +class pass_ipa_icf : public ipa_opt_pass_d +{ +public: + pass_ipa_icf (gcc::context *ctxt) + : ipa_opt_pass_d (pass_data_ipa_icf, ctxt, + ipa_icf_generate_summary, /* generate_summary */ + ipa_icf_write_summary, /* write_summary */ + ipa_icf_read_summary, /* read_summary */ + NULL, /* + write_optimization_summary */ + NULL, /* + read_optimization_summary */ + NULL, /* stmt_fixup */ + 0, /* function_transform_todo_flags_start */ + NULL, /* function_transform */ + NULL) /* variable_transform */ + {} + + /* opt_pass methods: */ + virtual bool gate (function *) + { + return flag_ipa_icf_variables || flag_ipa_icf_functions; + } + + virtual unsigned int execute (function *) + { + return ipa_icf_driver(); + } +}; // class pass_ipa_icf + +} // ipa_icf namespace + +ipa_opt_pass_d * +make_pass_ipa_icf (gcc::context *ctxt) +{ + return new ipa_icf::pass_ipa_icf (ctxt); +} |