Mercurial > hg > CbC > CbC_gcc
diff gcc/ipa-icf.c @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 84e7813d76e9 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gcc/ipa-icf.c Fri Oct 27 22:46:09 2017 +0900 @@ -0,0 +1,3695 @@ +/* Interprocedural Identical Code Folding pass + Copyright (C) 2014-2017 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" +#define INCLUDE_LIST +#include "system.h" +#include "coretypes.h" +#include "backend.h" +#include "target.h" +#include "rtl.h" +#include "tree.h" +#include "gimple.h" +#include "alloc-pool.h" +#include "tree-pass.h" +#include "ssa.h" +#include "cgraph.h" +#include "coverage.h" +#include "gimple-pretty-print.h" +#include "data-streamer.h" +#include "fold-const.h" +#include "calls.h" +#include "varasm.h" +#include "gimple-iterator.h" +#include "tree-cfg.h" +#include "symbol-summary.h" +#include "ipa-prop.h" +#include "ipa-fnsummary.h" +#include "except.h" +#include "attribs.h" +#include "print-tree.h" +#include "ipa-utils.h" +#include "ipa-icf-gimple.h" +#include "ipa-icf.h" +#include "stor-layout.h" +#include "dbgcnt.h" + +using namespace ipa_icf_gimple; + +namespace ipa_icf { + +/* Initialization and computation of symtab node hash, there data + are propagated later on. */ + +static sem_item_optimizer *optimizer = NULL; + +/* Constructor. */ + +symbol_compare_collection::symbol_compare_collection (symtab_node *node) +{ + m_references.create (0); + m_interposables.create (0); + + ipa_ref *ref; + + if (is_a <varpool_node *> (node) && DECL_VIRTUAL_P (node->decl)) + return; + + for (unsigned i = 0; node->iterate_reference (i, ref); i++) + { + if (ref->address_matters_p ()) + m_references.safe_push (ref->referred); + + if (ref->referred->get_availability () <= AVAIL_INTERPOSABLE) + { + if (ref->address_matters_p ()) + m_references.safe_push (ref->referred); + else + m_interposables.safe_push (ref->referred); + } + } + + if (is_a <cgraph_node *> (node)) + { + cgraph_node *cnode = dyn_cast <cgraph_node *> (node); + + for (cgraph_edge *e = cnode->callees; e; e = e->next_callee) + if (e->callee->get_availability () <= AVAIL_INTERPOSABLE) + m_interposables.safe_push (e->callee); + } +} + +/* 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) +{ +} + +sem_item::sem_item (sem_item_type _type, bitmap_obstack *stack) +: type (_type), m_hash (-1), m_hash_set (false) +{ + setup (stack); +} + +sem_item::sem_item (sem_item_type _type, symtab_node *_node, + bitmap_obstack *stack) +: type (_type), node (_node), m_hash (-1), m_hash_set (false) +{ + 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 (tree:%p)\n", type == FUNC ? "func" : "var", + node->dump_name (), (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]->node->name (), + i < refs.length() - 1 ? "," : ""); + + fprintf (dump_file, "\n"); + } +} + +/* Return true if target supports alias symbols. */ + +bool +sem_item::target_supports_symbol_aliases_p (void) +{ +#if !defined (ASM_OUTPUT_DEF) || (!defined(ASM_OUTPUT_WEAK_ALIAS) && !defined (ASM_WEAKEN_DECL)) + return false; +#else + return true; +#endif +} + +void sem_item::set_hash (hashval_t hash) +{ + m_hash = hash; + m_hash_set = true; +} + +/* 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) +{ + bb_sizes.create (0); + bb_sorted.create (0); +} + +sem_function::sem_function (cgraph_node *node, bitmap_obstack *stack) +: sem_item (FUNC, node, stack), m_checker (NULL), m_compared_func (NULL) +{ + bb_sizes.create (0); + bb_sorted.create (0); +} + +sem_function::~sem_function () +{ + for (unsigned i = 0; i < bb_sorted.length (); i++) + delete (bb_sorted[i]); + + 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 (!m_hash_set) + { + 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]); + + /* Add common features of declaration itself. */ + if (DECL_FUNCTION_SPECIFIC_TARGET (decl)) + hstate.add_hwi + (cl_target_option_hash + (TREE_TARGET_OPTION (DECL_FUNCTION_SPECIFIC_TARGET (decl)))); + if (DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl)) + hstate.add_hwi + (cl_optimization_hash + (TREE_OPTIMIZATION (DECL_FUNCTION_SPECIFIC_OPTIMIZATION (decl)))); + hstate.add_flag (DECL_CXX_CONSTRUCTOR_P (decl)); + hstate.add_flag (DECL_CXX_DESTRUCTOR_P (decl)); + + set_hash (hstate.end ()); + } + + return m_hash; +} + +/* Return ture if A1 and A2 represent equivalent function attribute lists. + Based on comp_type_attributes. */ + +bool +sem_item::compare_attributes (const_tree a1, const_tree a2) +{ + const_tree a; + if (a1 == a2) + return true; + for (a = a1; a != NULL_TREE; a = TREE_CHAIN (a)) + { + const struct attribute_spec *as; + const_tree attr; + + as = lookup_attribute_spec (get_attribute_name (a)); + /* TODO: We can introduce as->affects_decl_identity + and as->affects_decl_reference_identity if attribute mismatch + gets a common reason to give up on merging. It may not be worth + the effort. + For example returns_nonnull affects only references, while + optimize attribute can be ignored because it is already lowered + into flags representation and compared separately. */ + if (!as) + continue; + + attr = lookup_attribute (as->name, CONST_CAST_TREE (a2)); + if (!attr || !attribute_value_equal (a, attr)) + break; + } + if (!a) + { + for (a = a2; a != NULL_TREE; a = TREE_CHAIN (a)) + { + const struct attribute_spec *as; + + as = lookup_attribute_spec (get_attribute_name (a)); + if (!as) + continue; + + if (!lookup_attribute (as->name, CONST_CAST_TREE (a1))) + break; + /* We don't need to compare trees again, as we did this + already in first loop. */ + } + if (!a) + return true; + } + /* TODO: As in comp_type_attributes we may want to introduce target hook. */ + return false; +} + +/* Compare properties of symbols N1 and N2 that does not affect semantics of + symbol itself but affects semantics of its references from USED_BY (which + may be NULL if it is unknown). If comparsion is false, symbols + can still be merged but any symbols referring them can't. + + If ADDRESS is true, do extra checking needed for IPA_REF_ADDR. + + TODO: We can also split attributes to those that determine codegen of + a function body/variable constructor itself and those that are used when + referring to it. */ + +bool +sem_item::compare_referenced_symbol_properties (symtab_node *used_by, + symtab_node *n1, + symtab_node *n2, + bool address) +{ + if (is_a <cgraph_node *> (n1)) + { + /* Inline properties matters: we do now want to merge uses of inline + function to uses of normal function because inline hint would be lost. + We however can merge inline function to noinline because the alias + will keep its DECL_DECLARED_INLINE flag. + + Also ignore inline flag when optimizing for size or when function + is known to not be inlinable. + + TODO: the optimize_size checks can also be assumed to be true if + unit has no !optimize_size functions. */ + + if ((!used_by || address || !is_a <cgraph_node *> (used_by) + || !opt_for_fn (used_by->decl, optimize_size)) + && !opt_for_fn (n1->decl, optimize_size) + && n1->get_availability () > AVAIL_INTERPOSABLE + && (!DECL_UNINLINABLE (n1->decl) || !DECL_UNINLINABLE (n2->decl))) + { + if (DECL_DISREGARD_INLINE_LIMITS (n1->decl) + != DECL_DISREGARD_INLINE_LIMITS (n2->decl)) + return return_false_with_msg + ("DECL_DISREGARD_INLINE_LIMITS are different"); + + if (DECL_DECLARED_INLINE_P (n1->decl) + != DECL_DECLARED_INLINE_P (n2->decl)) + return return_false_with_msg ("inline attributes are different"); + } + + if (DECL_IS_OPERATOR_NEW (n1->decl) + != DECL_IS_OPERATOR_NEW (n2->decl)) + return return_false_with_msg ("operator new flags are different"); + } + + /* Merging two definitions with a reference to equivalent vtables, but + belonging to a different type may result in ipa-polymorphic-call analysis + giving a wrong answer about the dynamic type of instance. */ + if (is_a <varpool_node *> (n1)) + { + if ((DECL_VIRTUAL_P (n1->decl) || DECL_VIRTUAL_P (n2->decl)) + && (DECL_VIRTUAL_P (n1->decl) != DECL_VIRTUAL_P (n2->decl) + || !types_must_be_same_for_odr (DECL_CONTEXT (n1->decl), + DECL_CONTEXT (n2->decl))) + && (!used_by || !is_a <cgraph_node *> (used_by) || address + || opt_for_fn (used_by->decl, flag_devirtualize))) + return return_false_with_msg + ("references to virtual tables can not be merged"); + + if (address && DECL_ALIGN (n1->decl) != DECL_ALIGN (n2->decl)) + return return_false_with_msg ("alignment mismatch"); + + /* For functions we compare attributes in equals_wpa, because we do + not know what attributes may cause codegen differences, but for + variables just compare attributes for references - the codegen + for constructors is affected only by those attributes that we lower + to explicit representation (such as DECL_ALIGN or DECL_SECTION). */ + if (!compare_attributes (DECL_ATTRIBUTES (n1->decl), + DECL_ATTRIBUTES (n2->decl))) + return return_false_with_msg ("different var decl attributes"); + if (comp_type_attributes (TREE_TYPE (n1->decl), + TREE_TYPE (n2->decl)) != 1) + return return_false_with_msg ("different var type attributes"); + } + + /* When matching virtual tables, be sure to also match information + relevant for polymorphic call analysis. */ + if (used_by && is_a <varpool_node *> (used_by) + && DECL_VIRTUAL_P (used_by->decl)) + { + if (DECL_VIRTUAL_P (n1->decl) != DECL_VIRTUAL_P (n2->decl)) + return return_false_with_msg ("virtual flag mismatch"); + if (DECL_VIRTUAL_P (n1->decl) && is_a <cgraph_node *> (n1) + && (DECL_FINAL_P (n1->decl) != DECL_FINAL_P (n2->decl))) + return return_false_with_msg ("final flag mismatch"); + } + return true; +} + +/* Hash properties that are compared by compare_referenced_symbol_properties. */ + +void +sem_item::hash_referenced_symbol_properties (symtab_node *ref, + inchash::hash &hstate, + bool address) +{ + if (is_a <cgraph_node *> (ref)) + { + if ((type != FUNC || address || !opt_for_fn (decl, optimize_size)) + && !opt_for_fn (ref->decl, optimize_size) + && !DECL_UNINLINABLE (ref->decl)) + { + hstate.add_flag (DECL_DISREGARD_INLINE_LIMITS (ref->decl)); + hstate.add_flag (DECL_DECLARED_INLINE_P (ref->decl)); + } + hstate.add_flag (DECL_IS_OPERATOR_NEW (ref->decl)); + } + else if (is_a <varpool_node *> (ref)) + { + hstate.add_flag (DECL_VIRTUAL_P (ref->decl)); + if (address) + hstate.add_int (DECL_ALIGN (ref->decl)); + } +} + + +/* 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. ADDRESS indicate if address is taken. */ + +bool +sem_item::compare_symbol_references ( + hash_map <symtab_node *, sem_item *> &ignored_nodes, + symtab_node *n1, symtab_node *n2, bool address) +{ + enum availability avail1, avail2; + + if (n1 == n2) + return true; + + /* Never match variable and function. */ + if (is_a <varpool_node *> (n1) != is_a <varpool_node *> (n2)) + return false; + + if (!compare_referenced_symbol_properties (node, n1, n2, address)) + return false; + if (address && n1->equal_address_to (n2) == 1) + return true; + if (!address && n1->semantically_equivalent_p (n2)) + return true; + + n1 = n1->ultimate_alias_target (&avail1); + n2 = n2->ultimate_alias_target (&avail2); + + if (avail1 > AVAIL_INTERPOSABLE && ignored_nodes.get (n1) + && avail2 > AVAIL_INTERPOSABLE && ignored_nodes.get (n2)) + return true; + + 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; +} + +/* Return true if parameter I may be used. */ + +bool +sem_function::param_used_p (unsigned int i) +{ + if (ipa_node_params_sum == NULL) + return true; + + struct ipa_node_params *parms_info = IPA_NODE_REF (get_node ()); + + if (vec_safe_length (parms_info->descriptors) <= i) + return true; + + return ipa_is_param_used (IPA_NODE_REF (get_node ()), i); +} + +/* Perform additional check needed to match types function parameters that are + used. Unlike for normal decls it matters if type is TYPE_RESTRICT and we + make an assumption that REFERENCE_TYPE parameters are always non-NULL. */ + +bool +sem_function::compatible_parm_types_p (tree parm1, tree parm2) +{ + /* Be sure that parameters are TBAA compatible. */ + if (!func_checker::compatible_types_p (parm1, parm2)) + return return_false_with_msg ("parameter type is not compatible"); + + if (POINTER_TYPE_P (parm1) + && (TYPE_RESTRICT (parm1) != TYPE_RESTRICT (parm2))) + return return_false_with_msg ("argument restrict flag mismatch"); + + /* nonnull_arg_p implies non-zero range to REFERENCE types. */ + if (POINTER_TYPE_P (parm1) + && TREE_CODE (parm1) != TREE_CODE (parm2) + && opt_for_fn (decl, flag_delete_null_pointer_checks)) + return return_false_with_msg ("pointer wrt reference mismatch"); + + 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); + cgraph_node *cnode = dyn_cast <cgraph_node *> (node); + cgraph_node *cnode2 = dyn_cast <cgraph_node *> (item->node); + + m_compared_func = static_cast<sem_function *> (item); + + if (cnode->thunk.thunk_p != cnode2->thunk.thunk_p) + return return_false_with_msg ("thunk_p mismatch"); + + if (cnode->thunk.thunk_p) + { + if (cnode->thunk.fixed_offset != cnode2->thunk.fixed_offset) + return return_false_with_msg ("thunk fixed_offset mismatch"); + if (cnode->thunk.virtual_value != cnode2->thunk.virtual_value) + return return_false_with_msg ("thunk virtual_value mismatch"); + if (cnode->thunk.this_adjusting != cnode2->thunk.this_adjusting) + return return_false_with_msg ("thunk this_adjusting mismatch"); + if (cnode->thunk.virtual_offset_p != cnode2->thunk.virtual_offset_p) + return return_false_with_msg ("thunk virtual_offset_p mismatch"); + if (cnode->thunk.add_pointer_bounds_args + != cnode2->thunk.add_pointer_bounds_args) + return return_false_with_msg ("thunk add_pointer_bounds_args mismatch"); + } + + /* Compare special function DECL attributes. */ + if (DECL_FUNCTION_PERSONALITY (decl) + != DECL_FUNCTION_PERSONALITY (item->decl)) + return return_false_with_msg ("function personalities are different"); + + if (DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (decl) + != DECL_NO_INSTRUMENT_FUNCTION_ENTRY_EXIT (item->decl)) + return return_false_with_msg ("intrument function entry exit " + "attributes are different"); + + if (DECL_NO_LIMIT_STACK (decl) != DECL_NO_LIMIT_STACK (item->decl)) + return return_false_with_msg ("no stack limit attributes are different"); + + if (DECL_CXX_CONSTRUCTOR_P (decl) != DECL_CXX_CONSTRUCTOR_P (item->decl)) + return return_false_with_msg ("DECL_CXX_CONSTRUCTOR mismatch"); + + if (DECL_CXX_DESTRUCTOR_P (decl) != DECL_CXX_DESTRUCTOR_P (item->decl)) + return return_false_with_msg ("DECL_CXX_DESTRUCTOR mismatch"); + + /* TODO: pure/const flags mostly matters only for references, except for + the fact that codegen takes LOOPING flag as a hint that loops are + finite. We may arrange the code to always pick leader that has least + specified flags and then this can go into comparing symbol properties. */ + if (flags_from_decl_or_type (decl) != flags_from_decl_or_type (item->decl)) + return return_false_with_msg ("decl_or_type flags are different"); + + /* Do not match polymorphic constructors of different types. They calls + type memory location for ipa-polymorphic-call and we do not want + it to get confused by wrong type. */ + if (DECL_CXX_CONSTRUCTOR_P (decl) + && TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE) + { + if (TREE_CODE (TREE_TYPE (item->decl)) != METHOD_TYPE) + return return_false_with_msg ("DECL_CXX_CONSTURCTOR type mismatch"); + else if (!func_checker::compatible_polymorphic_types_p + (TYPE_METHOD_BASETYPE (TREE_TYPE (decl)), + TYPE_METHOD_BASETYPE (TREE_TYPE (item->decl)), false)) + return return_false_with_msg ("ctor polymorphic type mismatch"); + } + + /* Checking function TARGET and OPTIMIZATION flags. */ + cl_target_option *tar1 = target_opts_for_fn (decl); + cl_target_option *tar2 = target_opts_for_fn (item->decl); + + if (tar1 != tar2 && !cl_target_option_eq (tar1, tar2)) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "target flags difference"); + cl_target_option_print_diff (dump_file, 2, tar1, tar2); + } + + return return_false_with_msg ("Target flags are different"); + } + + cl_optimization *opt1 = opts_for_fn (decl); + cl_optimization *opt2 = opts_for_fn (item->decl); + + if (opt1 != opt2 && memcmp (opt1, opt2, sizeof(cl_optimization))) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "optimization flags difference"); + cl_optimization_print_diff (dump_file, 2, opt1, opt2); + } + + return return_false_with_msg ("optimization flags are different"); + } + + /* Result type checking. */ + if (!func_checker::compatible_types_p + (TREE_TYPE (TREE_TYPE (decl)), + TREE_TYPE (TREE_TYPE (m_compared_func->decl)))) + return return_false_with_msg ("result types are different"); + + /* Checking types of arguments. */ + tree list1 = TYPE_ARG_TYPES (TREE_TYPE (decl)), + list2 = TYPE_ARG_TYPES (TREE_TYPE (m_compared_func->decl)); + for (unsigned i = 0; list1 && list2; + list1 = TREE_CHAIN (list1), list2 = TREE_CHAIN (list2), i++) + { + tree parm1 = TREE_VALUE (list1); + tree parm2 = TREE_VALUE (list2); + + /* This guard is here for function pointer with attributes (pr59927.c). */ + if (!parm1 || !parm2) + return return_false_with_msg ("NULL argument type"); + + /* Verify that types are compatible to ensure that both functions + have same calling conventions. */ + if (!types_compatible_p (parm1, parm2)) + return return_false_with_msg ("parameter types are not compatible"); + + if (!param_used_p (i)) + continue; + + /* Perform additional checks for used parameters. */ + if (!compatible_parm_types_p (parm1, parm2)) + return false; + } + + if (list1 || list2) + return return_false_with_msg ("Mismatched number of parameters"); + + if (node->num_references () != item->node->num_references ()) + return return_false_with_msg ("different number of references"); + + /* Checking function attributes. + This is quadratic in number of attributes */ + if (comp_type_attributes (TREE_TYPE (decl), + TREE_TYPE (item->decl)) != 1) + return return_false_with_msg ("different type attributes"); + if (!compare_attributes (DECL_ATTRIBUTES (decl), + DECL_ATTRIBUTES (item->decl))) + return return_false_with_msg ("different decl attributes"); + + /* The type of THIS pointer type memory location for + ipa-polymorphic-call-analysis. */ + if (opt_for_fn (decl, flag_devirtualize) + && (TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE + || TREE_CODE (TREE_TYPE (item->decl)) == METHOD_TYPE) + && param_used_p (0) + && compare_polymorphic_p ()) + { + if (TREE_CODE (TREE_TYPE (decl)) != TREE_CODE (TREE_TYPE (item->decl))) + return return_false_with_msg ("METHOD_TYPE and FUNCTION_TYPE mismatch"); + if (!func_checker::compatible_polymorphic_types_p + (TYPE_METHOD_BASETYPE (TREE_TYPE (decl)), + TYPE_METHOD_BASETYPE (TREE_TYPE (item->decl)), false)) + return return_false_with_msg ("THIS pointer ODR type mismatch"); + } + + ipa_ref *ref = NULL, *ref2 = NULL; + for (unsigned i = 0; node->iterate_reference (i, ref); i++) + { + item->node->iterate_reference (i, ref2); + + if (ref->use != ref2->use) + return return_false_with_msg ("reference use mismatch"); + + if (!compare_symbol_references (ignored_nodes, ref->referred, + ref2->referred, + ref->address_matters_p ())) + 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_symbol_references (ignored_nodes, e1->callee, + e2->callee, false)) + return false; + if (!compare_edge_flags (e1, e2)) + return false; + + e1 = e1->next_callee; + e2 = e2->next_callee; + } + + if (e1 || e2) + return return_false_with_msg ("different number of calls"); + + e1 = dyn_cast <cgraph_node *> (node)->indirect_calls; + e2 = dyn_cast <cgraph_node *> (item->node)->indirect_calls; + + while (e1 && e2) + { + if (!compare_edge_flags (e1, e2)) + return false; + + e1 = e1->next_callee; + e2 = e2->next_callee; + } + + if (e1 || e2) + return return_false_with_msg ("different number of indirect calls"); + + return true; +} + +/* Update hash by address sensitive references. We iterate over all + sensitive references (address_matters_p) and we hash ultime alias + target of these nodes, which can improve a semantic item hash. + + Also hash in referenced symbols properties. This can be done at any time + (as the properties should not change), but it is convenient to do it here + while we walk the references anyway. */ + +void +sem_item::update_hash_by_addr_refs (hash_map <symtab_node *, + sem_item *> &m_symtab_node_map) +{ + ipa_ref* ref; + inchash::hash hstate (get_hash ()); + + for (unsigned i = 0; node->iterate_reference (i, ref); i++) + { + hstate.add_int (ref->use); + hash_referenced_symbol_properties (ref->referred, hstate, + ref->use == IPA_REF_ADDR); + if (ref->address_matters_p () || !m_symtab_node_map.get (ref->referred)) + hstate.add_int (ref->referred->ultimate_alias_target ()->order); + } + + if (is_a <cgraph_node *> (node)) + { + for (cgraph_edge *e = dyn_cast <cgraph_node *> (node)->callers; e; + e = e->next_caller) + { + sem_item **result = m_symtab_node_map.get (e->callee); + hash_referenced_symbol_properties (e->callee, hstate, false); + if (!result) + hstate.add_int (e->callee->ultimate_alias_target ()->order); + } + } + + set_hash (hstate.end ()); +} + +/* Update hash by computed local hash values taken from different + semantic items. + TODO: stronger SCC based hashing would be desirable here. */ + +void +sem_item::update_hash_by_local_refs (hash_map <symtab_node *, + sem_item *> &m_symtab_node_map) +{ + ipa_ref* ref; + inchash::hash state (get_hash ()); + + for (unsigned j = 0; node->iterate_reference (j, ref); j++) + { + sem_item **result = m_symtab_node_map.get (ref->referring); + if (result) + state.merge_hash ((*result)->get_hash ()); + } + + if (type == FUNC) + { + for (cgraph_edge *e = dyn_cast <cgraph_node *> (node)->callees; e; + e = e->next_callee) + { + sem_item **result = m_symtab_node_map.get (e->caller); + if (result) + state.merge_hash ((*result)->get_hash ()); + } + } + + global_hash = state.end (); +} + +/* Returns true if the item equals to ITEM given as argument. */ + +bool +sem_function::equals (sem_item *item, + hash_map <symtab_node *, sem_item *> &) +{ + gcc_assert (item->type == FUNC); + bool eq = equals_private (item); + + 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 with result: %s\n\n", + node->dump_name (), + item->node->dump_name (), + eq ? "true" : "false"); + + return eq; +} + +/* Processes function equality comparison. */ + +bool +sem_function::equals_private (sem_item *item) +{ + if (item->type != FUNC) + return false; + + basic_block bb1, bb2; + edge e1, e2; + edge_iterator ei1, ei2; + 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 (); + + m_checker = new func_checker (decl, m_compared_func->decl, + compare_polymorphic_p (), + false, + &refs_set, + &m_compared_func->refs_set); + arg1 = DECL_ARGUMENTS (decl); + arg2 = DECL_ARGUMENTS (m_compared_func->decl); + for (unsigned i = 0; + arg1 && arg2; arg1 = DECL_CHAIN (arg1), arg2 = DECL_CHAIN (arg2), i++) + { + if (!types_compatible_p (TREE_TYPE (arg1), TREE_TYPE (arg2))) + return return_false_with_msg ("argument types are not compatible"); + if (!param_used_p (i)) + continue; + /* Perform additional checks for used parameters. */ + if (!compatible_parm_types_p (TREE_TYPE (arg1), TREE_TYPE (arg2))) + return false; + if (!m_checker->compare_decl (arg1, arg2)) + return return_false (); + } + if (arg1 || arg2) + return return_false_with_msg ("Mismatched number of arguments"); + + if (!dyn_cast <cgraph_node *> (node)->has_gimple_body_p ()) + return true; + + /* 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"); + + auto_vec <int> bb_dict; + + /* Basic block edges check. */ + for (unsigned i = 0; i < bb_sorted.length (); ++i) + { + 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; +} + +/* Set LOCAL_P of NODE to true if DATA is non-NULL. + Helper for call_for_symbol_thunks_and_aliases. */ + +static bool +set_local (cgraph_node *node, void *data) +{ + node->local.local = data != NULL; + return false; +} + +/* TREE_ADDRESSABLE of NODE to true. + Helper for call_for_symbol_thunks_and_aliases. */ + +static bool +set_addressable (varpool_node *node, void *) +{ + TREE_ADDRESSABLE (node->decl) = 1; + return false; +} + +/* Clear DECL_RTL of NODE. + Helper for call_for_symbol_thunks_and_aliases. */ + +static bool +clear_decl_rtl (symtab_node *node, void *) +{ + SET_DECL_RTL (node->decl, NULL); + return false; +} + +/* Redirect all callers of N and its aliases to TO. Remove aliases if + possible. Return number of redirections made. */ + +static int +redirect_all_callers (cgraph_node *n, cgraph_node *to) +{ + int nredirected = 0; + ipa_ref *ref; + cgraph_edge *e = n->callers; + + while (e) + { + /* Redirecting thunks to interposable symbols or symbols in other sections + may not be supported by target output code. Play safe for now and + punt on redirection. */ + if (!e->caller->thunk.thunk_p) + { + struct cgraph_edge *nexte = e->next_caller; + e->redirect_callee (to); + e = nexte; + nredirected++; + } + else + e = e->next_callee; + } + for (unsigned i = 0; n->iterate_direct_aliases (i, ref);) + { + bool removed = false; + cgraph_node *n_alias = dyn_cast <cgraph_node *> (ref->referring); + + if ((DECL_COMDAT_GROUP (n->decl) + && (DECL_COMDAT_GROUP (n->decl) + == DECL_COMDAT_GROUP (n_alias->decl))) + || (n_alias->get_availability () > AVAIL_INTERPOSABLE + && n->get_availability () > AVAIL_INTERPOSABLE)) + { + nredirected += redirect_all_callers (n_alias, to); + if (n_alias->can_remove_if_no_direct_calls_p () + && !n_alias->call_for_symbol_and_aliases (cgraph_node::has_thunk_p, + NULL, true) + && !n_alias->has_aliases_p ()) + n_alias->remove (); + } + if (!removed) + i++; + } + return nredirected; +} + +/* 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 = NULL; + cgraph_node *alias = alias_func->get_node (); + + bool create_wrapper = false; + bool create_alias = false; + bool redirect_callers = false; + bool remove = false; + + bool original_discardable = false; + bool original_discarded = false; + + bool original_address_matters = original->address_matters_p (); + bool alias_address_matters = alias->address_matters_p (); + + if (DECL_EXTERNAL (alias->decl)) + { + if (dump_file) + fprintf (dump_file, "Not unifying; alias is external.\n\n"); + return false; + } + + if (DECL_NO_INLINE_WARNING_P (original->decl) + != DECL_NO_INLINE_WARNING_P (alias->decl)) + { + if (dump_file) + fprintf (dump_file, + "Not unifying; " + "DECL_NO_INLINE_WARNING mismatch.\n\n"); + return 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 (original->can_be_discarded_p ()) + original_discardable = true; + /* Also consider case where we have resolution info and we know that + original's definition is not going to be used. In this case we can not + create alias to original. */ + if (node->resolution != LDPR_UNKNOWN + && !decl_binds_to_current_def_p (node->decl)) + original_discardable = original_discarded = true; + + /* Creating a symtab alias is the optimal way to merge. + It however can not be used in the following cases: + + 1) if ORIGINAL and ALIAS may be possibly compared for address equality. + 2) if ORIGINAL is in a section that may be discarded by linker or if + it is an external functions where we can not create an alias + (ORIGINAL_DISCARDABLE) + 3) if target do not support symbol aliases. + 4) original and alias lie in different comdat groups. + + If we can not produce alias, we will turn ALIAS into WRAPPER of ORIGINAL + and/or redirect all callers from ALIAS to ORIGINAL. */ + if ((original_address_matters && alias_address_matters) + || (original_discardable + && (!DECL_COMDAT_GROUP (alias->decl) + || (DECL_COMDAT_GROUP (alias->decl) + != DECL_COMDAT_GROUP (original->decl)))) + || original_discarded + || !sem_item::target_supports_symbol_aliases_p () + || DECL_COMDAT_GROUP (alias->decl) != DECL_COMDAT_GROUP (original->decl)) + { + /* First see if we can produce wrapper. */ + + /* Symbol properties that matter for references must be preserved. + TODO: We can produce wrapper, but we need to produce alias of ORIGINAL + with proper properties. */ + if (!sem_item::compare_referenced_symbol_properties (NULL, original, alias, + alias->address_taken)) + { + if (dump_file) + fprintf (dump_file, + "Wrapper cannot be created because referenced symbol " + "properties mismatch\n"); + } + /* Do not turn function in one comdat group into wrapper to another + comdat group. Other compiler producing the body of the + another comdat group may make opossite decision and with unfortunate + linker choices this may close a loop. */ + else if (DECL_COMDAT_GROUP (original->decl) + && DECL_COMDAT_GROUP (alias->decl) + && (DECL_COMDAT_GROUP (alias->decl) + != DECL_COMDAT_GROUP (original->decl))) + { + if (dump_file) + fprintf (dump_file, + "Wrapper cannot be created because of COMDAT\n"); + } + else if (DECL_STATIC_CHAIN (alias->decl) + || DECL_STATIC_CHAIN (original->decl)) + { + if (dump_file) + fprintf (dump_file, + "Cannot create wrapper of nested function.\n"); + } + /* TODO: We can also deal with variadic functions never calling + VA_START. */ + else if (stdarg_p (TREE_TYPE (alias->decl))) + { + if (dump_file) + fprintf (dump_file, + "can not create wrapper of stdarg function.\n"); + } + else if (ipa_fn_summaries + && ipa_fn_summaries->get (alias)->self_size <= 2) + { + if (dump_file) + fprintf (dump_file, "Wrapper creation is not " + "profitable (function is too small).\n"); + } + /* If user paid attention to mark function noinline, assume it is + somewhat special and do not try to turn it into a wrapper that can + not be undone by inliner. */ + else if (lookup_attribute ("noinline", DECL_ATTRIBUTES (alias->decl))) + { + if (dump_file) + fprintf (dump_file, "Wrappers are not created for noinline.\n"); + } + else + create_wrapper = true; + + /* We can redirect local calls in the case both alias and orignal + are not interposable. */ + redirect_callers + = alias->get_availability () > AVAIL_INTERPOSABLE + && original->get_availability () > AVAIL_INTERPOSABLE + && !alias->instrumented_version; + /* TODO: We can redirect, but we need to produce alias of ORIGINAL + with proper properties. */ + if (!sem_item::compare_referenced_symbol_properties (NULL, original, alias, + alias->address_taken)) + redirect_callers = false; + + if (!redirect_callers && !create_wrapper) + { + if (dump_file) + fprintf (dump_file, "Not unifying; can not redirect callers nor " + "produce wrapper\n\n"); + return false; + } + + /* Work out the symbol the wrapper should call. + If ORIGINAL is interposable, we need to call a local alias. + Also produce local alias (if possible) as an optimization. + + Local aliases can not be created inside comdat groups because that + prevents inlining. */ + if (!original_discardable && !original->get_comdat_group ()) + { + local_original + = dyn_cast <cgraph_node *> (original->noninterposable_alias ()); + if (!local_original + && original->get_availability () > AVAIL_INTERPOSABLE) + local_original = original; + } + /* If we can not use local alias, fallback to the original + when possible. */ + else if (original->get_availability () > AVAIL_INTERPOSABLE) + local_original = original; + + /* If original is COMDAT local, we can not really redirect calls outside + of its comdat group to it. */ + if (original->comdat_local_p ()) + redirect_callers = false; + if (!local_original) + { + if (dump_file) + fprintf (dump_file, "Not unifying; " + "can not produce local alias.\n\n"); + return false; + } + + if (!redirect_callers && !create_wrapper) + { + if (dump_file) + fprintf (dump_file, "Not unifying; " + "can not redirect callers nor produce a wrapper\n\n"); + return false; + } + if (!create_wrapper + && !alias->call_for_symbol_and_aliases (cgraph_node::has_thunk_p, + NULL, true) + && !alias->can_remove_if_no_direct_calls_p ()) + { + if (dump_file) + fprintf (dump_file, "Not unifying; can not make wrapper and " + "function has other uses than direct calls\n\n"); + return false; + } + } + else + create_alias = true; + + if (redirect_callers) + { + int nredirected = redirect_all_callers (alias, local_original); + + if (nredirected) + { + alias->icf_merged = true; + local_original->icf_merged = true; + + if (dump_file && nredirected) + fprintf (dump_file, "%i local calls have been " + "redirected.\n", nredirected); + } + + /* If all callers was redirected, do not produce wrapper. */ + if (alias->can_remove_if_no_direct_calls_p () + && !DECL_VIRTUAL_P (alias->decl) + && !alias->has_aliases_p ()) + { + create_wrapper = false; + remove = true; + } + gcc_assert (!create_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 (); + /* Notice global symbol possibly produced RTL. */ + ((symtab_node *)alias)->call_for_symbol_and_aliases (clear_decl_rtl, + NULL, true); + + /* Create the alias. */ + cgraph_node::create_alias (alias_func->decl, decl); + alias->resolve_alias (original); + + original->call_for_symbol_thunks_and_aliases + (set_local, (void *)(size_t) original->local_p (), true); + + if (dump_file) + fprintf (dump_file, "Unified; Function alias has been created.\n\n"); + } + if (create_wrapper) + { + gcc_assert (!create_alias); + alias->icf_merged = true; + local_original->icf_merged = true; + + /* FIXME update local_original counts. */ + ipa_merge_profiles (original, alias, true); + alias->create_wrapper (local_original); + + if (dump_file) + fprintf (dump_file, "Unified; Wrapper has been created.\n\n"); + } + + /* It's possible that redirection can hit thunks that block + redirection opportunities. */ + gcc_assert (alias->icf_merged || remove || redirect_callers); + original->icf_merged = true; + + /* We use merged flag to track cases where COMDAT function is known to be + compatible its callers. If we merged in non-COMDAT, we need to give up + on this optimization. */ + if (original->merged_comdat && !alias->merged_comdat) + { + if (dump_file) + fprintf (dump_file, "Dropping merged_comdat flag.\n\n"); + if (local_original) + local_original->merged_comdat = false; + original->merged_comdat = false; + } + + if (remove) + { + ipa_merge_profiles (original, alias); + alias->release_body (); + alias->reset (); + alias->body_removed = true; + alias->icf_merged = true; + if (dump_file) + fprintf (dump_file, "Unified; Function body was removed.\n"); + } + + return true; +} + +/* Semantic item initialization function. */ + +void +sem_function::init (void) +{ + if (in_lto_p) + get_node ()->get_untransformed_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); + cgraph_node *cnode = dyn_cast <cgraph_node *> (node); + if (!cnode->thunk.thunk_p) + { + 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 + && gimple_code (stmt) != GIMPLE_PREDICT) + { + hash_stmt (stmt, hstate); + nondbg_stmt_count++; + } + } + + hstate.commit_flag (); + 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); + } + } + else + { + cfg_checksum = 0; + inchash::hash hstate; + hstate.add_hwi (cnode->thunk.fixed_offset); + hstate.add_hwi (cnode->thunk.virtual_value); + hstate.add_flag (cnode->thunk.this_adjusting); + hstate.add_flag (cnode->thunk.virtual_offset_p); + hstate.add_flag (cnode->thunk.add_pointer_bounds_args); + gcode_hash = hstate.end (); + } +} + +/* Accumulate to HSTATE a hash of expression EXP. + Identical to inchash::add_expr, but guaranteed to be stable across LTO + and DECL equality classes. */ + +void +sem_item::add_expr (const_tree exp, inchash::hash &hstate) +{ + if (exp == NULL_TREE) + { + hstate.merge_hash (0); + return; + } + + /* Handled component can be matched in a cureful way proving equivalence + even if they syntactically differ. Just skip them. */ + STRIP_NOPS (exp); + while (handled_component_p (exp)) + exp = TREE_OPERAND (exp, 0); + + enum tree_code code = TREE_CODE (exp); + hstate.add_int (code); + + switch (code) + { + /* Use inchash::add_expr for everything that is LTO stable. */ + case VOID_CST: + case INTEGER_CST: + case REAL_CST: + case FIXED_CST: + case STRING_CST: + case COMPLEX_CST: + case VECTOR_CST: + inchash::add_expr (exp, hstate); + break; + case CONSTRUCTOR: + { + unsigned HOST_WIDE_INT idx; + tree value; + + hstate.add_hwi (int_size_in_bytes (TREE_TYPE (exp))); + + FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (exp), idx, value) + if (value) + add_expr (value, hstate); + break; + } + case ADDR_EXPR: + case FDESC_EXPR: + add_expr (get_base_address (TREE_OPERAND (exp, 0)), hstate); + break; + case SSA_NAME: + case VAR_DECL: + case CONST_DECL: + case PARM_DECL: + hstate.add_hwi (int_size_in_bytes (TREE_TYPE (exp))); + break; + case MEM_REF: + case POINTER_PLUS_EXPR: + case MINUS_EXPR: + case RANGE_EXPR: + add_expr (TREE_OPERAND (exp, 0), hstate); + add_expr (TREE_OPERAND (exp, 1), hstate); + break; + case PLUS_EXPR: + { + inchash::hash one, two; + add_expr (TREE_OPERAND (exp, 0), one); + add_expr (TREE_OPERAND (exp, 1), two); + hstate.add_commutative (one, two); + } + break; + CASE_CONVERT: + hstate.add_hwi (int_size_in_bytes (TREE_TYPE (exp))); + return add_expr (TREE_OPERAND (exp, 0), hstate); + default: + break; + } +} + +/* Accumulate to HSTATE a hash of type t. + TYpes that may end up being compatible after LTO type merging needs to have + the same hash. */ + +void +sem_item::add_type (const_tree type, inchash::hash &hstate) +{ + if (type == NULL_TREE) + { + hstate.merge_hash (0); + return; + } + + type = TYPE_MAIN_VARIANT (type); + + hstate.add_int (TYPE_MODE (type)); + + if (TREE_CODE (type) == COMPLEX_TYPE) + { + hstate.add_int (COMPLEX_TYPE); + sem_item::add_type (TREE_TYPE (type), hstate); + } + else if (INTEGRAL_TYPE_P (type)) + { + hstate.add_int (INTEGER_TYPE); + hstate.add_flag (TYPE_UNSIGNED (type)); + hstate.add_int (TYPE_PRECISION (type)); + } + else if (VECTOR_TYPE_P (type)) + { + hstate.add_int (VECTOR_TYPE); + hstate.add_int (TYPE_PRECISION (type)); + sem_item::add_type (TREE_TYPE (type), hstate); + } + else if (TREE_CODE (type) == ARRAY_TYPE) + { + hstate.add_int (ARRAY_TYPE); + /* Do not hash size, so complete and incomplete types can match. */ + sem_item::add_type (TREE_TYPE (type), hstate); + } + else if (RECORD_OR_UNION_TYPE_P (type)) + { + gcc_checking_assert (COMPLETE_TYPE_P (type)); + hashval_t *val = optimizer->m_type_hash_cache.get (type); + + if (!val) + { + inchash::hash hstate2; + unsigned nf; + tree f; + hashval_t hash; + + hstate2.add_int (RECORD_TYPE); + gcc_assert (COMPLETE_TYPE_P (type)); + + for (f = TYPE_FIELDS (type), nf = 0; f; f = TREE_CHAIN (f)) + if (TREE_CODE (f) == FIELD_DECL) + { + add_type (TREE_TYPE (f), hstate2); + nf++; + } + + hstate2.add_int (nf); + hash = hstate2.end (); + hstate.add_hwi (hash); + optimizer->m_type_hash_cache.put (type, hash); + } + else + hstate.add_hwi (*val); + } +} + +/* Improve accumulated hash for HSTATE based on a gimple statement STMT. */ + +void +sem_function::hash_stmt (gimple *stmt, inchash::hash &hstate) +{ + enum gimple_code code = gimple_code (stmt); + + hstate.add_int (code); + + switch (code) + { + case GIMPLE_SWITCH: + add_expr (gimple_switch_index (as_a <gswitch *> (stmt)), hstate); + break; + case GIMPLE_ASSIGN: + hstate.add_int (gimple_assign_rhs_code (stmt)); + if (commutative_tree_code (gimple_assign_rhs_code (stmt)) + || commutative_ternary_tree_code (gimple_assign_rhs_code (stmt))) + { + inchash::hash one, two; + + add_expr (gimple_assign_rhs1 (stmt), one); + add_type (TREE_TYPE (gimple_assign_rhs1 (stmt)), one); + add_expr (gimple_assign_rhs2 (stmt), two); + hstate.add_commutative (one, two); + if (commutative_ternary_tree_code (gimple_assign_rhs_code (stmt))) + { + add_expr (gimple_assign_rhs3 (stmt), hstate); + add_type (TREE_TYPE (gimple_assign_rhs3 (stmt)), hstate); + } + add_expr (gimple_assign_lhs (stmt), hstate); + add_type (TREE_TYPE (gimple_assign_lhs (stmt)), two); + break; + } + /* fall through */ + case GIMPLE_CALL: + case GIMPLE_ASM: + case GIMPLE_COND: + case GIMPLE_GOTO: + case GIMPLE_RETURN: + /* All these statements are equivalent if their operands are. */ + for (unsigned i = 0; i < gimple_num_ops (stmt); ++i) + { + add_expr (gimple_op (stmt, i), hstate); + if (gimple_op (stmt, i)) + add_type (TREE_TYPE (gimple_op (stmt, i)), hstate); + } + /* Consider nocf_check attribute in hash as it affects code + generation. */ + if (code == GIMPLE_CALL + && flag_cf_protection & CF_BRANCH) + hstate.add_flag (gimple_call_nocf_check_p (as_a <gcall *> (stmt))); + default: + break; + } +} + + +/* Return true if polymorphic comparison must be processed. */ + +bool +sem_function::compare_polymorphic_p (void) +{ + struct cgraph_edge *e; + + if (!opt_for_fn (get_node ()->decl, flag_devirtualize)) + return false; + if (get_node ()->indirect_calls != NULL) + return true; + /* TODO: We can do simple propagation determining what calls may lead to + a polymorphic call. */ + for (e = get_node ()->callees; e; e = e->next_callee) + if (e->callee->definition + && opt_for_fn (e->callee->decl, flag_devirtualize)) + return true; + return false; +} + +/* 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); + + if (!func || (!node->has_gimple_body_p () && !node->thunk.thunk_p)) + return NULL; + + if (lookup_attribute_by_prefix ("omp ", DECL_ATTRIBUTES (node->decl)) != NULL) + return NULL; + + if (lookup_attribute_by_prefix ("oacc ", + DECL_ATTRIBUTES (node->decl)) != NULL) + return NULL; + + /* PR ipa/70306. */ + if (DECL_STATIC_CONSTRUCTOR (node->decl) + || DECL_STATIC_DESTRUCTOR (node->decl)) + return NULL; + + sem_function *f = new sem_function (node, stack); + + f->init (); + + return f; +} + +/* 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) +{ + gphi_iterator si1, si2; + gphi *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 = si1.phi (); + phi2 = si2.phi (); + + tree phi_result1 = gimple_phi_result (phi1); + tree phi_result2 = gimple_phi_result (phi2); + + if (!m_checker->compare_operand (phi_result1, phi_result2)) + return return_false_with_msg ("PHI results are different"); + + 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 == OBJ_TYPE_REF); +} + +/* Basic blocks dictionary BB_DICT returns true if SOURCE index BB + corresponds to TARGET. */ + +bool +sem_function::bb_dict_test (vec<int> *bb_dict, int source, int target) +{ + source++; + target++; + + if (bb_dict->length () <= (unsigned)source) + bb_dict->safe_grow_cleared (source + 1); + + if ((*bb_dict)[source] == 0) + { + (*bb_dict)[source] = target; + return true; + } + else + return (*bb_dict)[source] == target; +} + +sem_variable::sem_variable (bitmap_obstack *stack): sem_item (VAR, stack) +{ +} + +sem_variable::sem_variable (varpool_node *node, bitmap_obstack *stack) +: sem_item (VAR, node, stack) +{ + gcc_checking_assert (node); + gcc_checking_assert (get_node ()); +} + +/* Fast equality function based on knowledge known in WPA. */ + +bool +sem_variable::equals_wpa (sem_item *item, + hash_map <symtab_node *, sem_item *> &ignored_nodes) +{ + gcc_assert (item->type == VAR); + + if (node->num_references () != item->node->num_references ()) + return return_false_with_msg ("different number of references"); + + if (DECL_TLS_MODEL (decl) || DECL_TLS_MODEL (item->decl)) + return return_false_with_msg ("TLS model"); + + /* DECL_ALIGN is safe to merge, because we will always chose the largest + alignment out of all aliases. */ + + if (DECL_VIRTUAL_P (decl) != DECL_VIRTUAL_P (item->decl)) + return return_false_with_msg ("Virtual flag mismatch"); + + if (DECL_SIZE (decl) != DECL_SIZE (item->decl) + && ((!DECL_SIZE (decl) || !DECL_SIZE (item->decl)) + || !operand_equal_p (DECL_SIZE (decl), + DECL_SIZE (item->decl), OEP_ONLY_CONST))) + return return_false_with_msg ("size mismatch"); + + /* Do not attempt to mix data from different user sections; + we do not know what user intends with those. */ + if (((DECL_SECTION_NAME (decl) && !node->implicit_section) + || (DECL_SECTION_NAME (item->decl) && !item->node->implicit_section)) + && DECL_SECTION_NAME (decl) != DECL_SECTION_NAME (item->decl)) + return return_false_with_msg ("user section mismatch"); + + if (DECL_IN_TEXT_SECTION (decl) != DECL_IN_TEXT_SECTION (item->decl)) + return return_false_with_msg ("text section"); + + ipa_ref *ref = NULL, *ref2 = NULL; + for (unsigned i = 0; node->iterate_reference (i, ref); i++) + { + item->node->iterate_reference (i, ref2); + + if (ref->use != ref2->use) + return return_false_with_msg ("reference use mismatch"); + + if (!compare_symbol_references (ignored_nodes, + ref->referred, ref2->referred, + ref->address_matters_p ())) + return false; + } + + return true; +} + +/* Returns true if the item equals to ITEM given as argument. */ + +bool +sem_variable::equals (sem_item *item, + hash_map <symtab_node *, sem_item *> &) +{ + gcc_assert (item->type == VAR); + bool ret; + + if (DECL_INITIAL (decl) == error_mark_node && in_lto_p) + dyn_cast <varpool_node *>(node)->get_constructor (); + if (DECL_INITIAL (item->decl) == error_mark_node && in_lto_p) + dyn_cast <varpool_node *>(item->node)->get_constructor (); + + /* As seen in PR ipa/65303 we have to compare variables types. */ + if (!func_checker::compatible_types_p (TREE_TYPE (decl), + TREE_TYPE (item->decl))) + return return_false_with_msg ("variables types are different"); + + ret = sem_variable::equals (DECL_INITIAL (decl), + DECL_INITIAL (item->node->decl)); + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Equals called for vars: %s:%s with result: %s\n\n", + node->dump_name (), item->node->dump_name (), + ret ? "true" : "false"); + + return ret; +} + +/* Compares trees T1 and T2 for semantic equality. */ + +bool +sem_variable::equals (tree t1, tree t2) +{ + if (!t1 || !t2) + return return_with_debug (t1 == t2); + if (t1 == t2) + return true; + tree_code tc1 = TREE_CODE (t1); + tree_code tc2 = TREE_CODE (t2); + + if (tc1 != tc2) + return return_false_with_msg ("TREE_CODE mismatch"); + + switch (tc1) + { + case CONSTRUCTOR: + { + vec<constructor_elt, va_gc> *v1, *v2; + unsigned HOST_WIDE_INT idx; + + enum tree_code typecode = TREE_CODE (TREE_TYPE (t1)); + if (typecode != TREE_CODE (TREE_TYPE (t2))) + return return_false_with_msg ("constructor type mismatch"); + + if (typecode == ARRAY_TYPE) + { + HOST_WIDE_INT size_1 = int_size_in_bytes (TREE_TYPE (t1)); + /* For arrays, check that the sizes all match. */ + if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2)) + || size_1 == -1 + || size_1 != int_size_in_bytes (TREE_TYPE (t2))) + return return_false_with_msg ("constructor array size mismatch"); + } + else if (!func_checker::compatible_types_p (TREE_TYPE (t1), + TREE_TYPE (t2))) + return return_false_with_msg ("constructor type incompatible"); + + v1 = CONSTRUCTOR_ELTS (t1); + v2 = CONSTRUCTOR_ELTS (t2); + if (vec_safe_length (v1) != vec_safe_length (v2)) + return return_false_with_msg ("constructor number of elts mismatch"); + + for (idx = 0; idx < vec_safe_length (v1); ++idx) + { + constructor_elt *c1 = &(*v1)[idx]; + constructor_elt *c2 = &(*v2)[idx]; + + /* Check that each value is the same... */ + if (!sem_variable::equals (c1->value, c2->value)) + return false; + /* ... and that they apply to the same fields! */ + if (!sem_variable::equals (c1->index, c2->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))) + return return_false (); + + /* Type of the offset on MEM_REF does not matter. */ + return return_with_debug (sem_variable::equals (x1, x2) + && wi::to_offset (y1) + == wi::to_offset (y2)); + } + case ADDR_EXPR: + case FDESC_EXPR: + { + tree op1 = TREE_OPERAND (t1, 0); + tree op2 = TREE_OPERAND (t2, 0); + return sem_variable::equals (op1, op2); + } + /* References to other vars/decls are compared using ipa-ref. */ + case FUNCTION_DECL: + case VAR_DECL: + if (decl_in_symtab_p (t1) && decl_in_symtab_p (t2)) + return true; + return return_false_with_msg ("Declaration mismatch"); + case CONST_DECL: + /* TODO: We can check CONST_DECL by its DECL_INITIAL, but for that we + need to process its VAR/FUNCTION references without relying on ipa-ref + compare. */ + case FIELD_DECL: + case LABEL_DECL: + return return_false_with_msg ("Declaration mismatch"); + case INTEGER_CST: + /* Integer constants are the same only if the same width of type. */ + if (TYPE_PRECISION (TREE_TYPE (t1)) != TYPE_PRECISION (TREE_TYPE (t2))) + return return_false_with_msg ("INTEGER_CST precision mismatch"); + if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2))) + return return_false_with_msg ("INTEGER_CST mode mismatch"); + return return_with_debug (tree_int_cst_equal (t1, t2)); + case STRING_CST: + if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2))) + return return_false_with_msg ("STRING_CST mode mismatch"); + if (TREE_STRING_LENGTH (t1) != TREE_STRING_LENGTH (t2)) + return return_false_with_msg ("STRING_CST length mismatch"); + if (memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2), + TREE_STRING_LENGTH (t1))) + return return_false_with_msg ("STRING_CST mismatch"); + return true; + case FIXED_CST: + /* Fixed constants are the same only if the same width of type. */ + if (TYPE_PRECISION (TREE_TYPE (t1)) != TYPE_PRECISION (TREE_TYPE (t2))) + return return_false_with_msg ("FIXED_CST precision mismatch"); + + return return_with_debug (FIXED_VALUES_IDENTICAL (TREE_FIXED_CST (t1), + TREE_FIXED_CST (t2))); + case COMPLEX_CST: + return (sem_variable::equals (TREE_REALPART (t1), TREE_REALPART (t2)) + && sem_variable::equals (TREE_IMAGPART (t1), TREE_IMAGPART (t2))); + case REAL_CST: + /* Real constants are the same only if the same width of type. */ + if (TYPE_PRECISION (TREE_TYPE (t1)) != TYPE_PRECISION (TREE_TYPE (t2))) + return return_false_with_msg ("REAL_CST precision mismatch"); + return return_with_debug (real_identical (&TREE_REAL_CST (t1), + &TREE_REAL_CST (t2))); + case VECTOR_CST: + { + unsigned i; + + if (VECTOR_CST_NELTS (t1) != VECTOR_CST_NELTS (t2)) + return return_false_with_msg ("VECTOR_CST nelts mismatch"); + + for (i = 0; i < VECTOR_CST_NELTS (t1); ++i) + if (!sem_variable::equals (VECTOR_CST_ELT (t1, i), + VECTOR_CST_ELT (t2, i))) + return 0; + + return 1; + } + case ARRAY_REF: + case ARRAY_RANGE_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 (!sem_variable::equals (x1, x2) || !sem_variable::equals (y1, y2)) + return false; + if (!sem_variable::equals (array_ref_low_bound (t1), + array_ref_low_bound (t2))) + return false; + if (!sem_variable::equals (array_ref_element_size (t1), + array_ref_element_size (t2))) + return false; + return true; + } + + case COMPONENT_REF: + case POINTER_PLUS_EXPR: + case PLUS_EXPR: + case MINUS_EXPR: + case RANGE_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_CONVERT: + case VIEW_CONVERT_EXPR: + if (!func_checker::compatible_types_p (TREE_TYPE (t1), TREE_TYPE (t2))) + return return_false (); + return sem_variable::equals (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0)); + 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) +{ + if (TREE_THIS_VOLATILE (node->decl) || DECL_HARD_REGISTER (node->decl) + || node->alias) + return NULL; + + sem_variable *v = new sem_variable (node, stack); + + v->init (); + + return v; +} + +/* References independent hash function. */ + +hashval_t +sem_variable::get_hash (void) +{ + if (m_hash_set) + return m_hash; + + /* All WPA streamed in symbols should have their hashes computed at compile + time. At this point, the constructor may not be in memory at all. + DECL_INITIAL (decl) would be error_mark_node in that case. */ + gcc_assert (!node->lto_file_data); + tree ctor = DECL_INITIAL (decl); + inchash::hash hstate; + + hstate.add_int (456346417); + if (DECL_SIZE (decl) && tree_fits_shwi_p (DECL_SIZE (decl))) + hstate.add_hwi (tree_to_shwi (DECL_SIZE (decl))); + add_expr (ctor, hstate); + set_hash (hstate.end ()); + + return m_hash; +} + +/* Set all points-to UIDs of aliases pointing to node N as UID. */ + +static void +set_alias_uids (symtab_node *n, int uid) +{ + ipa_ref *ref; + FOR_EACH_ALIAS (n, ref) + { + if (dump_file) + fprintf (dump_file, " Setting points-to UID of [%s] as %d\n", + xstrdup_for_dump (ref->referring->asm_name ()), uid); + + SET_DECL_PT_UID (ref->referring->decl, uid); + set_alias_uids (ref->referring, uid); + } +} + +/* 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); + + if (!sem_item::target_supports_symbol_aliases_p ()) + { + if (dump_file) + fprintf (dump_file, "Not unifying; " + "Symbol aliases are not supported by target\n\n"); + return false; + } + + if (DECL_EXTERNAL (alias_item->decl)) + { + if (dump_file) + fprintf (dump_file, "Not unifying; alias is external.\n\n"); + return false; + } + + 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; + + bool alias_address_matters = alias->address_matters_p (); + + /* See if original is in a section that can be discarded if the main + symbol is not used. + Also consider case where we have resolution info and we know that + original's definition is not going to be used. In this case we can not + create alias to original. */ + if (original->can_be_discarded_p () + || (node->resolution != LDPR_UNKNOWN + && !decl_binds_to_current_def_p (node->decl))) + original_discardable = true; + + gcc_assert (!TREE_ASM_WRITTEN (alias->decl)); + + /* Constant pool machinery is not quite ready for aliases. + TODO: varasm code contains logic for merging DECL_IN_CONSTANT_POOL. + For LTO merging does not happen that is an important missing feature. + We can enable merging with LTO if the DECL_IN_CONSTANT_POOL + flag is dropped and non-local symbol name is assigned. */ + if (DECL_IN_CONSTANT_POOL (alias->decl) + || DECL_IN_CONSTANT_POOL (original->decl)) + { + if (dump_file) + fprintf (dump_file, + "Not unifying; constant pool variables.\n\n"); + return 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; + } + + /* We can not merge if address comparsion metters. */ + if (alias_address_matters && flag_merge_constants < 2) + { + if (dump_file) + fprintf (dump_file, + "Not unifying; address of original may be compared.\n\n"); + return false; + } + + if (DECL_ALIGN (original->decl) < DECL_ALIGN (alias->decl)) + { + if (dump_file) + fprintf (dump_file, "Not unifying; " + "original and alias have incompatible alignments\n\n"); + + return false; + } + + if (DECL_COMDAT_GROUP (original->decl) != DECL_COMDAT_GROUP (alias->decl)) + { + if (dump_file) + fprintf (dump_file, "Not unifying; alias cannot be created; " + "across comdat group boundary\n\n"); + + return false; + } + + if (original_discardable) + { + if (dump_file) + fprintf (dump_file, "Not unifying; alias cannot be created; " + "target is discardable\n\n"); + + return false; + } + else + { + gcc_assert (!original->alias); + gcc_assert (!alias->alias); + + alias->analyzed = false; + + DECL_INITIAL (alias->decl) = NULL; + ((symtab_node *)alias)->call_for_symbol_and_aliases (clear_decl_rtl, + NULL, true); + alias->need_bounds_init = false; + alias->remove_all_references (); + if (TREE_ADDRESSABLE (alias->decl)) + original->call_for_symbol_and_aliases (set_addressable, NULL, true); + + varpool_node::create_alias (alias_var->decl, decl); + alias->resolve_alias (original); + + if (dump_file) + fprintf (dump_file, "Unified; Variable alias has been created.\n"); + + set_alias_uids (original, DECL_UID (original->decl)); + return true; + } +} + +/* Dump symbol to FILE. */ + +void +sem_variable::dump_to_file (FILE *file) +{ + gcc_assert (file); + + print_node (file, "", decl, 0); + fprintf (file, "\n\n"); +} + +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_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 (); + free (*it); + } + + 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, file_data->mode_table); + + 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)\n", + node->dump_asm_name (), (void *) node->decl); + + if (is_a<cgraph_node *> (node)) + { + cgraph_node *cnode = dyn_cast <cgraph_node *> (node); + + sem_function *fn = new sem_function (cnode, &m_bmstack); + fn->set_hash (hash); + m_items.safe_push (fn); + } + else + { + varpool_node *vnode = dyn_cast <varpool_node *> (node); + + sem_variable *var = new sem_variable (vnode, &m_bmstack); + var->set_hash (hash); + m_items.safe_push (var); + } + } + + lto_free_section_data (file_data, LTO_section_ipa_icf, NULL, data, + len); + lto_data_in_delete (data_in); +} + +/* Read 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) +{ + if (!m_cgraph_node_hooks) + m_cgraph_node_hooks = symtab->add_cgraph_removal_hook + (&sem_item_optimizer::cgraph_removal_hook, this); + + if (!m_varpool_node_hooks) + 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 (m_removed_items_set.contains (item->node)) + { + remove_item (item); + continue; + } + + if (item->type == FUNC) + { + cgraph_node *cnode = static_cast <sem_function *>(item)->get_node (); + + if (in_lto_p && (cnode->alias || cnode->body_removed)) + remove_item (item); + else + filtered.safe_push (item); + } + else /* VAR. */ + { + if (!flag_ipa_icf_variables) + remove_item (item); + else + { + /* Filter out non-readonly variables. */ + tree decl = item->decl; + if (TREE_READONLY (decl)) + filtered.safe_push (item); + else + 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 which returns true in case it processes + a merge operation. True is returned if there's a merge operation + processed. */ + +bool +sem_item_optimizer::execute (void) +{ + filter_removed_items (); + unregister_hooks (); + + build_graph (); + update_hash_by_addr_refs (); + 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 (); + + subdivide_classes_by_equality (true); + + if (dump_file) + fprintf (dump_file, "Dump after WPA based types groups\n"); + + dump_cong_classes (); + + process_cong_reduction (); + checking_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 (); + checking_verify_classes (); + bool merged_p = merge_classes (prev_class_count); + + if (dump_file && (dump_flags & TDF_DETAILS)) + symtab->dump (dump_file); + + return merged_p; +} + +/* 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->node->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; +} + +/* For each semantic item, append hash values of references. */ + +void +sem_item_optimizer::update_hash_by_addr_refs () +{ + /* First, append to hash sensitive references and class type if it need to + be matched for ODR. */ + for (unsigned i = 0; i < m_items.length (); i++) + { + m_items[i]->update_hash_by_addr_refs (m_symtab_node_map); + if (m_items[i]->type == FUNC) + { + if (TREE_CODE (TREE_TYPE (m_items[i]->decl)) == METHOD_TYPE + && contains_polymorphic_type_p + (TYPE_METHOD_BASETYPE (TREE_TYPE (m_items[i]->decl))) + && (DECL_CXX_CONSTRUCTOR_P (m_items[i]->decl) + || (static_cast<sem_function *> (m_items[i])->param_used_p (0) + && static_cast<sem_function *> (m_items[i]) + ->compare_polymorphic_p ()))) + { + tree class_type + = TYPE_METHOD_BASETYPE (TREE_TYPE (m_items[i]->decl)); + inchash::hash hstate (m_items[i]->get_hash ()); + + if (TYPE_NAME (class_type) + && DECL_ASSEMBLER_NAME_SET_P (TYPE_NAME (class_type))) + hstate.add_hwi + (IDENTIFIER_HASH_VALUE + (DECL_ASSEMBLER_NAME (TYPE_NAME (class_type)))); + + m_items[i]->set_hash (hstate.end ()); + } + } + } + + /* Once all symbols have enhanced hash value, we can append + hash values of symbols that are seen by IPA ICF and are + references by a semantic item. Newly computed values + are saved to global_hash member variable. */ + for (unsigned i = 0; i < m_items.length (); i++) + m_items[i]->update_hash_by_local_refs (m_symtab_node_map); + + /* Global hash value replace current hash values. */ + for (unsigned i = 0; i < m_items.length (); i++) + m_items[i]->set_hash (m_items[i]->global_hash); +} + +/* 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); + + /* Initialize hash values if we are not in LTO mode. */ + if (!in_lto_p) + item->get_hash (); + } + + 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->ultimate_alias_target ()); + 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->ultimate_alias_target ()); + 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, + m_items.length () ? 100.0f * init_called_count / m_items.length () + : 0.0f); +} + +/* 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_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]); + } + } + } + + checking_verify_classes (); +} + +/* Subdivide classes by address references that members of the class + reference. Example can be a pair of functions that have an address + taken from a function. If these addresses are different the class + is split. */ + +unsigned +sem_item_optimizer::subdivide_classes_by_sensitive_refs () +{ + typedef hash_map <symbol_compare_hash, vec <sem_item *> > subdivide_hash_map; + + unsigned newly_created_classes = 0; + + for (hash_table <congruence_class_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + { + unsigned int class_count = (*it)->classes.length (); + auto_vec<congruence_class *> new_classes; + + for (unsigned i = 0; i < class_count; i++) + { + congruence_class *c = (*it)->classes[i]; + + if (c->members.length() > 1) + { + subdivide_hash_map split_map; + + for (unsigned j = 0; j < c->members.length (); j++) + { + sem_item *source_node = c->members[j]; + + symbol_compare_collection *collection + = new symbol_compare_collection (source_node->node); + + bool existed; + vec <sem_item *> *slot + = &split_map.get_or_insert (collection, &existed); + gcc_checking_assert (slot); + + slot->safe_push (source_node); + + if (existed) + delete collection; + } + + /* If the map contains more than one key, we have to split + the map appropriately. */ + if (split_map.elements () != 1) + { + bool first_class = true; + + for (subdivide_hash_map::iterator it2 = split_map.begin (); + it2 != split_map.end (); ++it2) + { + congruence_class *new_cls; + new_cls = new congruence_class (class_id++); + + for (unsigned k = 0; k < (*it2).second.length (); k++) + add_item_to_class (new_cls, (*it2).second[k]); + + worklist_push (new_cls); + newly_created_classes++; + + if (first_class) + { + (*it)->classes[i] = new_cls; + first_class = false; + } + else + { + new_classes.safe_push (new_cls); + m_classes_count++; + } + } + } + + /* Release memory. */ + for (subdivide_hash_map::iterator it2 = split_map.begin (); + it2 != split_map.end (); ++it2) + { + delete (*it2).first; + (*it2).second.release (); + } + } + } + + for (unsigned i = 0; i < new_classes.length (); i++) + (*it)->classes.safe_push (new_classes[i]); + } + + return newly_created_classes; +} + +/* Verify congruence classes, if checking is enabled. */ + +void +sem_item_optimizer::checking_verify_classes (void) +{ + if (flag_checking) + verify_classes (); +} + +/* Verify congruence classes. */ + +void +sem_item_optimizer::verify_classes (void) +{ + for (hash_table<congruence_class_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_assert (cls); + gcc_assert (cls->members.length () > 0); + + for (unsigned int j = 0; j < cls->members.length (); j++) + { + sem_item *item = cls->members[j]; + + gcc_assert (item); + gcc_assert (item->cls == cls); + + for (unsigned k = 0; k < item->usages.length (); k++) + { + sem_usage_pair *usage = item->usages[k]; + gcc_assert (usage->item->index_in_class + < usage->item->cls->members.length ()); + } + } + } + } +} + +/* 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 ()) + { + auto_vec <congruence_class *, 2> newclasses; + newclasses.quick_push (new congruence_class (class_id++)); + newclasses.quick_push (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]); + } + + if (flag_checking) + { + for (unsigned int i = 0; i < 2; i++) + gcc_assert (newclasses[i]->members.length ()); + } + + 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; + + gcc_checking_assert (usage->item->cls); + gcc_checking_assert (usage->item->index_in_class + < usage->item->cls->members.length ()); + + 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 congruence 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_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", + (unsigned long) worklist.size ()); + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Congruence class reduction\n"); + + congruence_class *cls; + + /* Process complete congruence reduction. */ + while ((cls = worklist_pop ()) != NULL) + do_congruence_step (cls); + + /* Subdivide newly created classes according to references. */ + unsigned new_classes = subdivide_classes_by_sensitive_refs (); + + if (dump_file) + fprintf (dump_file, "Address reference subdivision created: %u " + "new classes.\n", new_classes); +} + +/* 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, + (unsigned long) 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_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_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); +} + +/* Sort pair of sem_items A and B by DECL_UID. */ + +static int +sort_sem_items_by_decl_uid (const void *a, const void *b) +{ + const sem_item *i1 = *(const sem_item * const *)a; + const sem_item *i2 = *(const sem_item * const *)b; + + int uid1 = DECL_UID (i1->decl); + int uid2 = DECL_UID (i2->decl); + + if (uid1 < uid2) + return -1; + else if (uid1 > uid2) + return 1; + else + return 0; +} + +/* Sort pair of congruence_classes A and B by DECL_UID of the first member. */ + +static int +sort_congruence_classes_by_decl_uid (const void *a, const void *b) +{ + const congruence_class *c1 = *(const congruence_class * const *)a; + const congruence_class *c2 = *(const congruence_class * const *)b; + + int uid1 = DECL_UID (c1->members[0]->decl); + int uid2 = DECL_UID (c2->members[0]->decl); + + if (uid1 < uid2) + return -1; + else if (uid1 > uid2) + return 1; + else + return 0; +} + +/* Sort pair of congruence_class_groups A and B by + DECL_UID of the first member of a first group. */ + +static int +sort_congruence_class_groups_by_decl_uid (const void *a, const void *b) +{ + const congruence_class_group *g1 + = *(const congruence_class_group * const *)a; + const congruence_class_group *g2 + = *(const congruence_class_group * const *)b; + + int uid1 = DECL_UID (g1->classes[0]->members[0]->decl); + int uid2 = DECL_UID (g2->classes[0]->members[0]->decl); + + if (uid1 < uid2) + return -1; + else if (uid1 > uid2) + return 1; + else + return 0; +} + +/* 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. True is returned if there's a merge operation + processed. */ + +bool +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; + + bool merged_p = false; + + /* PR lto/78211 + Sort functions in congruence classes by DECL_UID and do the same + for the classes to not to break -fcompare-debug. */ + + for (hash_table<congruence_class_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]; + c->members.qsort (sort_sem_items_by_decl_uid); + } + + (*it)->classes.qsort (sort_congruence_classes_by_decl_uid); + } + + for (hash_table<congruence_class_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 (); + } + } + + auto_vec <congruence_class_group *> classes (m_classes.elements ()); + for (hash_table<congruence_class_hash>::iterator it = m_classes.begin (); + it != m_classes.end (); ++it) + classes.quick_push (*it); + + classes.qsort (sort_congruence_class_groups_by_decl_uid); + + 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", + prev_class_count ? 1.0f * item_count / prev_class_count : 0.0f, + class_count ? 1.0f * item_count / class_count : 0.0f); + fprintf (dump_file, "Average non-singular class size: %.2f, count: %u\n", + non_singular_classes_count ? 1.0f * non_singular_classes_sum / + non_singular_classes_count : 0.0f, + non_singular_classes_count); + fprintf (dump_file, "Equal symbols: %u\n", equal_items); + fprintf (dump_file, "Fraction of visited symbols: %.2f%%\n\n", + item_count ? 100.0f * equal_items / item_count : 0.0f); + } + + unsigned int l; + congruence_class_group *it; + FOR_EACH_VEC_ELT (classes, l, it) + for (unsigned int i = 0; i < it->classes.length (); i++) + { + congruence_class *c = it->classes[i]; + + if (c->members.length () == 1) + continue; + + sem_item *source = c->members[0]; + + if (DECL_NAME (source->decl) + && MAIN_NAME_P (DECL_NAME (source->decl))) + /* If merge via wrappers, picking main as the target can be + problematic. */ + source = c->members[1]; + + for (unsigned int j = 0; j < c->members.length (); j++) + { + sem_item *alias = c->members[j]; + + if (alias == source) + continue; + + if (dump_file) + { + fprintf (dump_file, "Semantic equality hit:%s->%s\n", + xstrdup_for_dump (source->node->name ()), + xstrdup_for_dump (alias->node->name ())); + fprintf (dump_file, "Assembler symbol names:%s->%s\n", + xstrdup_for_dump (source->node->asm_name ()), + xstrdup_for_dump (alias->node->asm_name ())); + } + + if (lookup_attribute ("no_icf", DECL_ATTRIBUTES (alias->decl))) + { + if (dump_file) + fprintf (dump_file, + "Merge operation is skipped due to no_icf " + "attribute.\n\n"); + + continue; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + source->dump_to_file (dump_file); + alias->dump_to_file (dump_file); + } + + if (dbg_cnt (merged_ipa_icf)) + merged_p |= source->merge (alias); + } + } + + return merged_p; +} + +/* 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 ", members[i]->node->dump_asm_name ()); + + 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; +} + +/* Generate pass summary for IPA ICF pass. */ + +static void +ipa_icf_generate_summary (void) +{ + if (!optimizer) + optimizer = new sem_item_optimizer (); + + optimizer->register_hooks (); + 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); + + bool merged_p = optimizer->execute (); + + delete optimizer; + optimizer = NULL; + + return merged_p ? TODO_remove_functions : 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 in_lto_p || 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); +}