--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ipa-icf.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,637 @@
+/* Interprocedural semantic function equality 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/>.  */
+
+namespace ipa_icf {
+class sem_item;
+
+/* Congruence class encompasses a collection of either functions or
+   read-only variables. These items are considered to be equivalent
+   if not proved the oposite.  */
+class congruence_class
+{
+public:
+  /* Congruence class constructor for a new class with _ID.  */
+  congruence_class (unsigned int _id): in_worklist (false), id(_id)
+  {
+  }
+
+  /* Destructor.  */
+  ~congruence_class ()
+  {
+  }
+
+  /* Dump function prints all class members to a FILE with an INDENT.  */
+  void dump (FILE *file, unsigned int indent = 0) const;
+
+  /* Returns true if there's a member that is used from another group.  */
+  bool is_class_used (void);
+
+  /* Flag is used in case we want to remove a class from worklist and
+     delete operation is quite expensive for
+     the data structure (linked list).  */
+  bool in_worklist;
+
+  /* Vector of all group members.  */
+  auto_vec <sem_item *> members;
+
+  /* Global unique class identifier.  */
+  unsigned int id;
+};
+
+/* Semantic item type enum.  */
+enum sem_item_type
+{
+  FUNC,
+  VAR
+};
+
+/* Class is container for address references for a symtab_node.  */
+
+class symbol_compare_collection
+{
+public:
+  /* Constructor.  */
+  symbol_compare_collection (symtab_node *node);
+
+  /* Destructor.  */
+  ~symbol_compare_collection ()
+  {
+    m_references.release ();
+    m_interposables.release ();
+  }
+
+  /* Vector of address references.  */
+  vec<symtab_node *> m_references;
+
+  /* Vector of interposable references.  */
+  vec<symtab_node *> m_interposables;
+};
+
+/* Hash traits for symbol_compare_collection map.  */
+
+struct symbol_compare_hash : nofree_ptr_hash <symbol_compare_collection>
+{
+  static hashval_t
+  hash (value_type v)
+  {
+    inchash::hash hstate;
+    hstate.add_int (v->m_references.length ());
+
+    for (unsigned i = 0; i < v->m_references.length (); i++)
+      hstate.add_int (v->m_references[i]->ultimate_alias_target ()->order);
+
+    hstate.add_int (v->m_interposables.length ());
+
+    for (unsigned i = 0; i < v->m_interposables.length (); i++)
+      hstate.add_int (v->m_interposables[i]->ultimate_alias_target ()->order);
+
+    return hstate.end ();
+  }
+
+  static bool
+  equal (value_type a, value_type b)
+  {
+    if (a->m_references.length () != b->m_references.length ()
+	|| a->m_interposables.length () != b->m_interposables.length ())
+      return false;
+
+    for (unsigned i = 0; i < a->m_references.length (); i++)
+      if (a->m_references[i]->equal_address_to (b->m_references[i]) != 1)
+	return false;
+
+    for (unsigned i = 0; i < a->m_interposables.length (); i++)
+      if (!a->m_interposables[i]->semantically_equivalent_p
+	(b->m_interposables[i]))
+	return false;
+
+    return true;
+  }
+};
+
+
+/* Semantic item usage pair.  */
+class sem_usage_pair
+{
+public:
+  /* Constructor for key value pair, where _ITEM is key and _INDEX is a target.  */
+  sem_usage_pair (sem_item *_item, unsigned int _index);
+
+  /* Target semantic item where an item is used.  */
+  sem_item *item;
+
+  /* Index of usage of such an item.  */
+  unsigned int index;
+};
+
+/* Semantic item is a base class that encapsulates all shared functionality
+   for both semantic function and variable items.  */
+class sem_item
+{
+public:
+  /* Semantic item constructor for a node of _TYPE, where STACK is used
+     for bitmap memory allocation.  */
+  sem_item (sem_item_type _type, bitmap_obstack *stack);
+
+  /* Semantic item constructor for a node of _TYPE, where STACK is used
+     for bitmap memory allocation.  The item is based on symtab node _NODE.  */
+  sem_item (sem_item_type _type, symtab_node *_node, bitmap_obstack *stack);
+
+  virtual ~sem_item ();
+
+  /* Dump function for debugging purpose.  */
+  DEBUG_FUNCTION void dump (void);
+
+  /* Initialize semantic item by info reachable during LTO WPA phase.  */
+  virtual void init_wpa (void) = 0;
+
+  /* Semantic item initialization function.  */
+  virtual void init (void) = 0;
+
+  /* Add reference to a semantic TARGET.  */
+  void add_reference (sem_item *target);
+
+  /* Fast equality function based on knowledge known in WPA.  */
+  virtual bool equals_wpa (sem_item *item,
+			   hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0;
+
+  /* Returns true if the item equals to ITEM given as arguemnt.  */
+  virtual bool equals (sem_item *item,
+		       hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0;
+
+  /* References independent hash function.  */
+  virtual hashval_t get_hash (void) = 0;
+
+  /* Set new hash value of the item.  */
+  void set_hash (hashval_t hash);
+
+  /* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can
+     be applied.  */
+  virtual bool merge (sem_item *alias_item) = 0;
+
+  /* Dump symbol to FILE.  */
+  virtual void dump_to_file (FILE *file) = 0;
+
+  /* Update hash by address sensitive references.  */
+  void update_hash_by_addr_refs (hash_map <symtab_node *,
+				 sem_item *> &m_symtab_node_map);
+
+  /* Update hash by computed local hash values taken from different
+     semantic items.  */
+  void update_hash_by_local_refs (hash_map <symtab_node *,
+				  sem_item *> &m_symtab_node_map);
+
+  /* Return base tree that can be used for compatible_types_p and
+     contains_polymorphic_type_p comparison.  */
+  static bool get_base_types (tree *t1, tree *t2);
+
+  /* Return true if target supports alias symbols.  */
+  bool target_supports_symbol_aliases_p (void);
+
+  /* Item type.  */
+  sem_item_type type;
+
+  /* Symtab node.  */
+  symtab_node *node;
+
+  /* Declaration tree node.  */
+  tree decl;
+
+  /* Semantic references used that generate congruence groups.  */
+  vec <sem_item *> refs;
+
+  /* Pointer to a congruence class the item belongs to.  */
+  congruence_class *cls;
+
+  /* Index of the item in a class belonging to.  */
+  unsigned int index_in_class;
+
+  /* List of semantic items where the instance is used.  */
+  vec <sem_usage_pair *> usages;
+
+  /* A bitmap with indices of all classes referencing this item.  */
+  bitmap usage_index_bitmap;
+
+  /* List of tree references (either FUNC_DECL or VAR_DECL).  */
+  vec <tree> tree_refs;
+
+  /* A set with symbol table references.  */
+  hash_set <symtab_node *> refs_set;
+
+  /* Temporary hash used where hash values of references are added.  */
+  hashval_t global_hash;
+protected:
+  /* Cached, once calculated hash for the item.  */
+
+  /* Accumulate to HSTATE a hash of expression EXP.  */
+  static void add_expr (const_tree exp, inchash::hash &hstate);
+  /* Accumulate to HSTATE a hash of type T.  */
+  static void add_type (const_tree t, inchash::hash &hstate);
+
+  /* Compare properties of symbol that does not affect semantics of symbol
+     itself but affects semantics of its references.
+     If ADDRESS is true, do extra checking needed for IPA_REF_ADDR.  */
+  static bool compare_referenced_symbol_properties (symtab_node *used_by,
+						    symtab_node *n1,
+					            symtab_node *n2,
+					            bool address);
+
+  /* Compare two attribute lists.  */
+  static bool compare_attributes (const_tree list1, const_tree list2);
+
+  /* Hash properties compared by compare_referenced_symbol_properties.  */
+  void hash_referenced_symbol_properties (symtab_node *ref,
+					  inchash::hash &hstate,
+					  bool address);
+
+  /* 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 compare_symbol_references (hash_map <symtab_node *, sem_item *>
+				  &ignored_nodes,
+				  symtab_node *n1, symtab_node *n2,
+				  bool address);
+protected:
+  /* Hash of item.  */
+  hashval_t m_hash;
+
+  /* Indicated whether a hash value has been set or not.  */
+  bool m_hash_set;
+
+private:
+  /* Initialize internal data structures. Bitmap STACK is used for
+     bitmap memory allocation process.  */
+  void setup (bitmap_obstack *stack);
+}; // class sem_item
+
+class sem_function: public sem_item
+{
+public:
+  /* Semantic function constructor that uses STACK as bitmap memory stack.  */
+  sem_function (bitmap_obstack *stack);
+
+  /*  Constructor based on callgraph node _NODE.
+      Bitmap STACK is used for memory allocation.  */
+  sem_function (cgraph_node *_node, bitmap_obstack *stack);
+
+  ~sem_function ();
+
+  inline virtual void init_wpa (void)
+  {
+  }
+
+  virtual void init (void);
+  virtual bool equals_wpa (sem_item *item,
+			   hash_map <symtab_node *, sem_item *> &ignored_nodes);
+  virtual hashval_t get_hash (void);
+  virtual bool equals (sem_item *item,
+		       hash_map <symtab_node *, sem_item *> &ignored_nodes);
+  virtual bool merge (sem_item *alias_item);
+
+  /* Dump symbol to FILE.  */
+  virtual void dump_to_file (FILE *file)
+  {
+    gcc_assert (file);
+    dump_function_to_file (decl, file, TDF_DETAILS);
+  }
+
+  /* Returns cgraph_node.  */
+  inline cgraph_node *get_node (void)
+  {
+    return dyn_cast <cgraph_node *> (node);
+  }
+
+  /* Improve accumulated hash for HSTATE based on a gimple statement STMT.  */
+  void hash_stmt (gimple *stmt, inchash::hash &inchash);
+
+  /* Return true if polymorphic comparison must be processed.  */
+  bool compare_polymorphic_p (void);
+
+  /* For a given call graph NODE, the function constructs new
+     semantic function item.  */
+  static sem_function *parse (cgraph_node *node, bitmap_obstack *stack);
+
+  /* Perform additional checks needed to match types of used function
+     paramters.  */
+  bool compatible_parm_types_p (tree, tree);
+
+  /* Exception handling region tree.  */
+  eh_region region_tree;
+
+  /* Number of function arguments.  */
+  unsigned int arg_count;
+
+  /* Total amount of edges in the function.  */
+  unsigned int edge_count;
+
+  /* Vector of sizes of all basic blocks.  */
+  vec <unsigned int> bb_sizes;
+
+  /* Control flow graph checksum.  */
+  hashval_t cfg_checksum;
+
+  /* GIMPLE codes hash value.  */
+  hashval_t gcode_hash;
+
+  /* Total number of SSA names used in the function.  */
+  unsigned ssa_names_size;
+
+  /* Array of structures for all basic blocks.  */
+  vec <ipa_icf_gimple::sem_bb *> bb_sorted;
+
+  /* Return true if parameter I may be used.  */
+  bool param_used_p (unsigned int i);
+
+private:
+  /* Calculates hash value based on a BASIC_BLOCK.  */
+  hashval_t get_bb_hash (const ipa_icf_gimple::sem_bb *basic_block);
+
+  /* For given basic blocks BB1 and BB2 (from functions FUNC1 and FUNC),
+     true value is returned if phi nodes are semantically
+     equivalent in these blocks .  */
+  bool compare_phi_node (basic_block bb1, basic_block bb2);
+
+  /* Basic blocks dictionary BB_DICT returns true if SOURCE index BB
+     corresponds to TARGET.  */
+  bool bb_dict_test (vec<int> *bb_dict, int source, int target);
+
+  /* If cgraph edges E1 and E2 are indirect calls, verify that
+     ICF flags are the same.  */
+  bool compare_edge_flags (cgraph_edge *e1, cgraph_edge *e2);
+
+  /* Processes function equality comparison.  */
+  bool equals_private (sem_item *item);
+
+  /* Returns true if tree T can be compared as a handled component.  */
+  static bool icf_handled_component_p (tree t);
+
+  /* Function checker stores binding between functions.   */
+  ipa_icf_gimple::func_checker *m_checker;
+
+  /* COMPARED_FUNC is a function that we compare to.  */
+  sem_function *m_compared_func;
+}; // class sem_function
+
+class sem_variable: public sem_item
+{
+public:
+  /* Semantic variable constructor that uses STACK as bitmap memory stack.  */
+  sem_variable (bitmap_obstack *stack);
+
+  /*  Constructor based on callgraph node _NODE.
+      Bitmap STACK is used for memory allocation.  */
+
+  sem_variable (varpool_node *_node, bitmap_obstack *stack);
+
+  inline virtual void init_wpa (void) {}
+
+  /* Semantic variable initialization function.  */
+  inline virtual void init (void)
+  {
+    decl = get_node ()->decl;
+  }
+
+  virtual hashval_t get_hash (void);
+  virtual bool merge (sem_item *alias_item);
+  virtual void dump_to_file (FILE *file);
+  virtual bool equals (sem_item *item,
+		       hash_map <symtab_node *, sem_item *> &ignored_nodes);
+
+  /* Fast equality variable based on knowledge known in WPA.  */
+  virtual bool equals_wpa (sem_item *item,
+			   hash_map <symtab_node *, sem_item *> &ignored_nodes);
+
+  /* Returns varpool_node.  */
+  inline varpool_node *get_node (void)
+  {
+    return dyn_cast <varpool_node *> (node);
+  }
+
+  /* Parser function that visits a varpool NODE.  */
+  static sem_variable *parse (varpool_node *node, bitmap_obstack *stack);
+
+private:
+  /* Compares trees T1 and T2 for semantic equality.  */
+  static bool equals (tree t1, tree t2);
+}; // class sem_variable
+
+class sem_item_optimizer;
+
+struct congruence_class_group
+{
+  hashval_t hash;
+  sem_item_type type;
+  vec <congruence_class *> classes;
+};
+
+/* Congruence class set structure.  */
+struct congruence_class_hash : nofree_ptr_hash <congruence_class_group>
+{
+  static inline hashval_t hash (const congruence_class_group *item)
+  {
+    return item->hash;
+  }
+
+  static inline int equal (const congruence_class_group *item1,
+			   const congruence_class_group *item2)
+  {
+    return item1->hash == item2->hash && item1->type == item2->type;
+  }
+};
+
+struct traverse_split_pair
+{
+  sem_item_optimizer *optimizer;
+  class congruence_class *cls;
+};
+
+/* Semantic item optimizer includes all top-level logic
+   related to semantic equality comparison.  */
+class sem_item_optimizer
+{
+public:
+  sem_item_optimizer ();
+  ~sem_item_optimizer ();
+
+  /* Function responsible for visiting all potential functions and
+     read-only variables that can be merged.  */
+  void parse_funcs_and_vars (void);
+
+  /* Optimizer entry point which returns true in case it processes
+     a merge operation. True is returned if there's a merge operation
+     processed.  */
+  bool execute (void);
+
+  /* Dump function. */
+  void dump (void);
+
+  /* Verify congruence classes if checking is enabled.  */
+  void checking_verify_classes (void);
+
+  /* Verify congruence classes.  */
+  void verify_classes (void);
+
+  /* Write IPA ICF summary for symbols.  */
+  void write_summary (void);
+
+  /* Read IPA ICF summary for symbols.  */
+  void read_summary (void);
+
+  /* Callgraph removal hook called for a NODE with a custom DATA.  */
+  static void cgraph_removal_hook (cgraph_node *node, void *data);
+
+  /* Varpool removal hook called for a NODE with a custom DATA.  */
+  static void varpool_removal_hook (varpool_node *node, void *data);
+
+  /* Worklist of congruence classes that can potentially
+     refine classes of congruence.  */
+  std::list<congruence_class *> worklist;
+
+  /* Remove semantic ITEM and release memory.  */
+  void remove_item (sem_item *item);
+
+  /* Remove symtab NODE triggered by symtab removal hooks.  */
+  void remove_symtab_node (symtab_node *node);
+
+  /* Register callgraph and varpool hooks.  */
+  void register_hooks (void);
+
+  /* Unregister callgraph and varpool hooks.  */
+  void unregister_hooks (void);
+
+  /* Adds a CLS to hashtable associated by hash value.  */
+  void add_class (congruence_class *cls);
+
+  /* Gets a congruence class group based on given HASH value and TYPE.  */
+  congruence_class_group *get_group_by_hash (hashval_t hash,
+      sem_item_type type);
+
+  /* Because types can be arbitrarily large, avoid quadratic bottleneck.  */
+  hash_map<const_tree, hashval_t> m_type_hash_cache;
+private:
+
+  /* For each semantic item, append hash values of references.  */
+  void update_hash_by_addr_refs ();
+
+  /* Congruence classes are built by hash value.  */
+  void build_hash_based_classes (void);
+
+  /* Semantic items in classes having more than one element and initialized.
+     In case of WPA, we load function body.  */
+  void parse_nonsingleton_classes (void);
+
+  /* Equality function for semantic items is used to subdivide existing
+     classes. If IN_WPA, fast equality function is invoked.  */
+  void subdivide_classes_by_equality (bool in_wpa = false);
+
+  /* Subdivide classes by address and interposable 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 subdivide_classes_by_sensitive_refs();
+
+  /* Debug function prints all informations about congruence classes.  */
+  void dump_cong_classes (void);
+
+  /* Build references according to call graph.  */
+  void build_graph (void);
+
+  /* Iterative congruence reduction function.  */
+  void process_cong_reduction (void);
+
+  /* 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 merge_classes (unsigned int prev_class_count);
+
+  /* Adds a newly created congruence class CLS to worklist.  */
+  void worklist_push (congruence_class *cls);
+
+  /* Pops a class from worklist. */
+  congruence_class *worklist_pop ();
+
+  /* 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 do_congruence_step (congruence_class *cls);
+
+  /* Tests if a class CLS used as INDEXth splits any congruence classes.
+     Bitmap stack BMSTACK is used for bitmap allocation.  */
+  void do_congruence_step_for_index (congruence_class *cls, unsigned int index);
+
+  /* Makes pairing between a congruence class CLS and semantic ITEM.  */
+  static void add_item_to_class (congruence_class *cls, sem_item *item);
+
+  /* Disposes split map traverse function. CLS is congruence
+     class, BSLOT is bitmap slot we want to release. DATA is mandatory,
+     but unused argument.  */
+  static bool release_split_map (congruence_class * const &cls, bitmap const &b,
+				 traverse_split_pair *pair);
+
+  /* Process split operation for a cognruence class CLS,
+     where bitmap B splits congruence class members. DATA is used
+     as argument of split pair.  */
+  static bool traverse_congruence_split (congruence_class * const &cls,
+					 bitmap const &b,
+					 traverse_split_pair *pair);
+
+  /* Reads a section from LTO stream file FILE_DATA. Input block for DATA
+     contains LEN bytes.  */
+  void read_section (lto_file_decl_data *file_data, const char *data,
+		     size_t len);
+
+  /* Removes all callgraph and varpool nodes that are marked by symtab
+     as deleted.  */
+  void filter_removed_items (void);
+
+  /* Vector of semantic items.  */
+  vec <sem_item *> m_items;
+
+  /* A set containing all items removed by hooks.  */
+  hash_set <symtab_node *> m_removed_items_set;
+
+  /* Hashtable of congruence classes.  */
+  hash_table <congruence_class_hash> m_classes;
+
+  /* Count of congruence classes.  */
+  unsigned int m_classes_count;
+
+  /* Map data structure maps symtab nodes to semantic items.  */
+  hash_map <symtab_node *, sem_item *> m_symtab_node_map;
+
+  /* Set to true if a splitter class is removed.  */
+  bool splitter_class_removed;
+
+  /* Global unique class id counter.  */
+  static unsigned int class_id;
+
+  /* Callgraph node removal hook holder.  */
+  cgraph_node_hook_list *m_cgraph_node_hooks;
+
+  /* Varpool node removal hook holder.  */
+  varpool_node_hook_list *m_varpool_node_hooks;
+
+  /* Bitmap stack.  */
+  bitmap_obstack m_bmstack;
+}; // class sem_item_optimizer
+
+} // ipa_icf namespace