1 /* Interprocedural semantic function equality pass
2 Copyright (C) 2014-2015 Free Software Foundation, Inc.
4 Contributed by Jan Hubicka <hubicka@ucw.cz> and Martin Liska <mliska@suse.cz>
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
25 /* Congruence class encompasses a collection of either functions or
26 read-only variables. These items are considered to be equivalent
27 if not proved the oposite. */
28 class congruence_class
31 /* Congruence class constructor for a new class with _ID. */
32 congruence_class (unsigned int _id
): in_worklist (false), id(_id
)
41 /* Dump function prints all class members to a FILE with an INDENT. */
42 void dump (FILE *file
, unsigned int indent
= 0) const;
44 /* Returns true if there's a member that is used from another group. */
45 bool is_class_used (void);
47 /* Flag is used in case we want to remove a class from worklist and
48 delete operation is quite expensive for
49 the data structure (linked list). */
52 /* Vector of all group members. */
53 auto_vec
<sem_item
*> members
;
55 /* Global unique class identifier. */
59 /* Semantic item type enum. */
66 /* Class is container for address references for a symtab_node. */
68 class symbol_compare_collection
72 symbol_compare_collection (symtab_node
*node
);
75 ~symbol_compare_collection ()
77 m_references
.release ();
78 m_interposables
.release ();
81 /* Vector of address references. */
82 vec
<symtab_node
*> m_references
;
84 /* Vector of interposable references. */
85 vec
<symtab_node
*> m_interposables
;
88 /* Hash traits for symbol_compare_collection map. */
90 struct symbol_compare_hashmap_traits
: default_hashmap_traits
93 hash (const symbol_compare_collection
*v
)
96 hstate
.add_int (v
->m_references
.length ());
98 for (unsigned i
= 0; i
< v
->m_references
.length (); i
++)
99 hstate
.add_ptr (v
->m_references
[i
]->ultimate_alias_target ());
101 hstate
.add_int (v
->m_interposables
.length ());
103 for (unsigned i
= 0; i
< v
->m_interposables
.length (); i
++)
104 hstate
.add_ptr (v
->m_interposables
[i
]->ultimate_alias_target ());
106 return hstate
.end ();
110 equal_keys (const symbol_compare_collection
*a
,
111 const symbol_compare_collection
*b
)
113 if (a
->m_references
.length () != b
->m_references
.length ())
116 for (unsigned i
= 0; i
< a
->m_references
.length (); i
++)
117 if (a
->m_references
[i
]->equal_address_to (b
->m_references
[i
]) != 1)
120 for (unsigned i
= 0; i
< a
->m_interposables
.length (); i
++)
121 if (!a
->m_interposables
[i
]->semantically_equivalent_p
122 (b
->m_interposables
[i
]))
130 /* Semantic item usage pair. */
134 /* Constructor for key value pair, where _ITEM is key and _INDEX is a target. */
135 sem_usage_pair (sem_item
*_item
, unsigned int _index
);
137 /* Target semantic item where an item is used. */
140 /* Index of usage of such an item. */
144 /* Semantic item is a base class that encapsulates all shared functionality
145 for both semantic function and variable items. */
149 /* Semantic item constructor for a node of _TYPE, where STACK is used
150 for bitmap memory allocation. */
151 sem_item (sem_item_type _type
, bitmap_obstack
*stack
);
153 /* Semantic item constructor for a node of _TYPE, where STACK is used
154 for bitmap memory allocation. The item is based on symtab node _NODE
155 with computed _HASH. */
156 sem_item (sem_item_type _type
, symtab_node
*_node
, hashval_t _hash
,
157 bitmap_obstack
*stack
);
159 virtual ~sem_item ();
161 /* Dump function for debugging purpose. */
162 DEBUG_FUNCTION
void dump (void);
164 /* Initialize semantic item by info reachable during LTO WPA phase. */
165 virtual void init_wpa (void) = 0;
167 /* Semantic item initialization function. */
168 virtual void init (void) = 0;
170 /* Add reference to a semantic TARGET. */
171 void add_reference (sem_item
*target
);
173 /* Gets symbol name of the item. */
174 const char *name (void)
176 return node
->name ();
179 /* Gets assembler name of the item. */
180 const char *asm_name (void)
182 return node
->asm_name ();
185 /* Fast equality function based on knowledge known in WPA. */
186 virtual bool equals_wpa (sem_item
*item
,
187 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
) = 0;
189 /* Returns true if the item equals to ITEM given as arguemnt. */
190 virtual bool equals (sem_item
*item
,
191 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
) = 0;
193 /* References independent hash function. */
194 virtual hashval_t
get_hash (void) = 0;
196 /* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can
198 virtual bool merge (sem_item
*alias_item
) = 0;
200 /* Dump symbol to FILE. */
201 virtual void dump_to_file (FILE *file
) = 0;
203 /* Return base tree that can be used for compatible_types_p and
204 contains_polymorphic_type_p comparison. */
205 static bool get_base_types (tree
*t1
, tree
*t2
);
207 /* Return true if target supports alias symbols. */
208 bool target_supports_symbol_aliases_p (void);
216 /* Declaration tree node. */
219 /* Semantic references used that generate congruence groups. */
220 vec
<sem_item
*> refs
;
222 /* Pointer to a congruence class the item belongs to. */
223 congruence_class
*cls
;
225 /* Index of the item in a class belonging to. */
226 unsigned int index_in_class
;
228 /* List of semantic items where the instance is used. */
229 vec
<sem_usage_pair
*> usages
;
231 /* A bitmap with indices of all classes referencing this item. */
232 bitmap usage_index_bitmap
;
234 /* List of tree references (either FUNC_DECL or VAR_DECL). */
235 vec
<tree
> tree_refs
;
237 /* A set with symbol table references. */
238 hash_set
<symtab_node
*> refs_set
;
241 /* Cached, once calculated hash for the item. */
245 /* Initialize internal data structures. Bitmap STACK is used for
246 bitmap memory allocation process. */
247 void setup (bitmap_obstack
*stack
);
250 class sem_function
: public sem_item
253 /* Semantic function constructor that uses STACK as bitmap memory stack. */
254 sem_function (bitmap_obstack
*stack
);
256 /* Constructor based on callgraph node _NODE with computed hash _HASH.
257 Bitmap STACK is used for memory allocation. */
258 sem_function (cgraph_node
*_node
, hashval_t _hash
, bitmap_obstack
*stack
);
262 inline virtual void init_wpa (void)
267 virtual void init (void);
268 virtual bool equals_wpa (sem_item
*item
,
269 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
);
270 virtual hashval_t
get_hash (void);
271 virtual bool equals (sem_item
*item
,
272 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
);
273 virtual bool merge (sem_item
*alias_item
);
275 /* Dump symbol to FILE. */
276 virtual void dump_to_file (FILE *file
)
279 dump_function_to_file (decl
, file
, TDF_DETAILS
);
282 /* Parses function arguments and result type. */
283 void parse_tree_args (void);
285 /* Returns cgraph_node. */
286 inline cgraph_node
*get_node (void)
288 return dyn_cast
<cgraph_node
*> (node
);
291 /* Improve accumulated hash for HSTATE based on a gimple statement STMT. */
292 void hash_stmt (inchash::hash
*inchash
, gimple stmt
);
294 /* Return true if polymorphic comparison must be processed. */
295 bool compare_polymorphic_p (void);
297 /* For a given call graph NODE, the function constructs new
298 semantic function item. */
299 static sem_function
*parse (cgraph_node
*node
, bitmap_obstack
*stack
);
301 /* Exception handling region tree. */
302 eh_region region_tree
;
304 /* Result type tree node. */
307 /* Array of argument tree types. */
308 vec
<tree
> arg_types
;
310 /* Number of function arguments. */
311 unsigned int arg_count
;
313 /* Total amount of edges in the function. */
314 unsigned int edge_count
;
316 /* Vector of sizes of all basic blocks. */
317 vec
<unsigned int> bb_sizes
;
319 /* Control flow graph checksum. */
320 hashval_t cfg_checksum
;
322 /* GIMPLE codes hash value. */
323 hashval_t gcode_hash
;
325 /* Total number of SSA names used in the function. */
326 unsigned ssa_names_size
;
328 /* Array of structures for all basic blocks. */
329 vec
<ipa_icf_gimple::sem_bb
*> bb_sorted
;
332 /* Calculates hash value based on a BASIC_BLOCK. */
333 hashval_t
get_bb_hash (const ipa_icf_gimple::sem_bb
*basic_block
);
335 /* For given basic blocks BB1 and BB2 (from functions FUNC1 and FUNC),
336 true value is returned if phi nodes are semantically
337 equivalent in these blocks . */
338 bool compare_phi_node (basic_block bb1
, basic_block bb2
);
340 /* Basic blocks dictionary BB_DICT returns true if SOURCE index BB
341 corresponds to TARGET. */
342 bool bb_dict_test (vec
<int> *bb_dict
, int source
, int target
);
344 /* Iterates all tree types in T1 and T2 and returns true if all types
345 are compatible. If COMPARE_POLYMORPHIC is set to true,
346 more strict comparison is executed. */
347 bool compare_type_list (tree t1
, tree t2
, bool compare_polymorphic
);
349 /* If cgraph edges E1 and E2 are indirect calls, verify that
350 ICF flags are the same. */
351 bool compare_edge_flags (cgraph_edge
*e1
, cgraph_edge
*e2
);
353 /* For a given symbol table nodes N1 and N2, we check that FUNCTION_DECLs
354 point to a same function. Comparison can be skipped if IGNORED_NODES
355 contains these nodes. */
356 bool compare_cgraph_references (hash_map
<symtab_node
*, sem_item
*>
358 symtab_node
*n1
, symtab_node
*n2
);
360 /* Processes function equality comparison. */
361 bool equals_private (sem_item
*item
,
362 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
);
364 /* Returns true if tree T can be compared as a handled component. */
365 static bool icf_handled_component_p (tree t
);
367 /* Function checker stores binding between functions. */
368 ipa_icf_gimple::func_checker
*m_checker
;
370 /* COMPARED_FUNC is a function that we compare to. */
371 sem_function
*m_compared_func
;
372 }; // class sem_function
374 class sem_variable
: public sem_item
377 /* Semantic variable constructor that uses STACK as bitmap memory stack. */
378 sem_variable (bitmap_obstack
*stack
);
380 /* Constructor based on callgraph node _NODE with computed hash _HASH.
381 Bitmap STACK is used for memory allocation. */
383 sem_variable (varpool_node
*_node
, hashval_t _hash
, bitmap_obstack
*stack
);
385 inline virtual void init_wpa (void) {}
387 /* Semantic variable initialization function. */
388 inline virtual void init (void)
390 decl
= get_node ()->decl
;
391 ctor
= ctor_for_folding (decl
);
394 virtual hashval_t
get_hash (void);
395 virtual bool merge (sem_item
*alias_item
);
396 virtual void dump_to_file (FILE *file
);
397 virtual bool equals (sem_item
*item
,
398 hash_map
<symtab_node
*, sem_item
*> &ignored_nodes
);
400 /* Fast equality variable based on knowledge known in WPA. */
401 inline virtual bool equals_wpa (sem_item
*item
,
402 hash_map
<symtab_node
*, sem_item
*> & ARG_UNUSED(ignored_nodes
))
404 gcc_assert (item
->type
== VAR
);
408 /* Returns varpool_node. */
409 inline varpool_node
*get_node (void)
411 return dyn_cast
<varpool_node
*> (node
);
414 /* Parser function that visits a varpool NODE. */
415 static sem_variable
*parse (varpool_node
*node
, bitmap_obstack
*stack
);
417 /* Variable constructor. */
421 /* Iterates though a constructor and identifies tree references
422 we are interested in semantic function equality. */
423 void parse_tree_refs (tree t
);
425 /* Compares trees T1 and T2 for semantic equality. */
426 static bool equals (tree t1
, tree t2
);
428 /* Compare that symbol sections are either NULL or have same name. */
429 bool compare_sections (sem_variable
*alias
);
431 }; // class sem_variable
433 class sem_item_optimizer
;
435 struct congruence_class_group
439 vec
<congruence_class
*> classes
;
442 /* Congruence class set structure. */
443 struct congruence_class_group_hash
: typed_noop_remove
<congruence_class_group
>
445 typedef congruence_class_group value_type
;
446 typedef congruence_class_group compare_type
;
448 static inline hashval_t
hash (const value_type
*item
)
453 static inline int equal (const value_type
*item1
, const compare_type
*item2
)
455 return item1
->hash
== item2
->hash
&& item1
->type
== item2
->type
;
459 struct traverse_split_pair
461 sem_item_optimizer
*optimizer
;
462 class congruence_class
*cls
;
465 /* Semantic item optimizer includes all top-level logic
466 related to semantic equality comparison. */
467 class sem_item_optimizer
470 sem_item_optimizer ();
471 ~sem_item_optimizer ();
473 /* Function responsible for visiting all potential functions and
474 read-only variables that can be merged. */
475 void parse_funcs_and_vars (void);
477 /* Optimizer entry point. */
483 /* Verify congruence classes if checking is enabled. */
484 void verify_classes (void);
486 /* Write IPA ICF summary for symbols. */
487 void write_summary (void);
489 /* Read IPA IPA ICF summary for symbols. */
490 void read_summary (void);
492 /* Callgraph removal hook called for a NODE with a custom DATA. */
493 static void cgraph_removal_hook (cgraph_node
*node
, void *data
);
495 /* Varpool removal hook called for a NODE with a custom DATA. */
496 static void varpool_removal_hook (varpool_node
*node
, void *data
);
498 /* Worklist of congruence classes that can potentially
499 refine classes of congruence. */
500 std::list
<congruence_class
*> worklist
;
502 /* Remove semantic ITEM and release memory. */
503 void remove_item (sem_item
*item
);
505 /* Remove symtab NODE triggered by symtab removal hooks. */
506 void remove_symtab_node (symtab_node
*node
);
508 /* Register callgraph and varpool hooks. */
509 void register_hooks (void);
511 /* Unregister callgraph and varpool hooks. */
512 void unregister_hooks (void);
514 /* Adds a CLS to hashtable associated by hash value. */
515 void add_class (congruence_class
*cls
);
517 /* Gets a congruence class group based on given HASH value and TYPE. */
518 congruence_class_group
*get_group_by_hash (hashval_t hash
,
523 /* Congruence classes are built by hash value. */
524 void build_hash_based_classes (void);
526 /* Semantic items in classes having more than one element and initialized.
527 In case of WPA, we load function body. */
528 void parse_nonsingleton_classes (void);
530 /* Equality function for semantic items is used to subdivide existing
531 classes. If IN_WPA, fast equality function is invoked. */
532 void subdivide_classes_by_equality (bool in_wpa
= false);
534 /* Subdivide classes by address and interposable references
535 that members of the class reference.
536 Example can be a pair of functions that have an address
537 taken from a function. If these addresses are different the class
539 unsigned subdivide_classes_by_sensitive_refs();
541 /* Debug function prints all informations about congruence classes. */
542 void dump_cong_classes (void);
544 /* Build references according to call graph. */
545 void build_graph (void);
547 /* Iterative congruence reduction function. */
548 void process_cong_reduction (void);
550 /* After reduction is done, we can declare all items in a group
551 to be equal. PREV_CLASS_COUNT is start number of classes
553 void merge_classes (unsigned int prev_class_count
);
555 /* Adds a newly created congruence class CLS to worklist. */
556 void worklist_push (congruence_class
*cls
);
558 /* Pops a class from worklist. */
559 congruence_class
*worklist_pop ();
561 /* Every usage of a congruence class CLS is a candidate that can split the
562 collection of classes. Bitmap stack BMSTACK is used for bitmap
564 void do_congruence_step (congruence_class
*cls
);
566 /* Tests if a class CLS used as INDEXth splits any congruence classes.
567 Bitmap stack BMSTACK is used for bitmap allocation. */
568 void do_congruence_step_for_index (congruence_class
*cls
, unsigned int index
);
570 /* Makes pairing between a congruence class CLS and semantic ITEM. */
571 static void add_item_to_class (congruence_class
*cls
, sem_item
*item
);
573 /* Disposes split map traverse function. CLS is congruence
574 class, BSLOT is bitmap slot we want to release. DATA is mandatory,
575 but unused argument. */
576 static bool release_split_map (congruence_class
* const &cls
, bitmap
const &b
,
577 traverse_split_pair
*pair
);
579 /* Process split operation for a cognruence class CLS,
580 where bitmap B splits congruence class members. DATA is used
581 as argument of split pair. */
582 static bool traverse_congruence_split (congruence_class
* const &cls
,
584 traverse_split_pair
*pair
);
586 /* Reads a section from LTO stream file FILE_DATA. Input block for DATA
587 contains LEN bytes. */
588 void read_section (lto_file_decl_data
*file_data
, const char *data
,
591 /* Removes all callgraph and varpool nodes that are marked by symtab
593 void filter_removed_items (void);
595 /* Vector of semantic items. */
596 vec
<sem_item
*> m_items
;
598 /* A set containing all items removed by hooks. */
599 hash_set
<symtab_node
*> m_removed_items_set
;
601 /* Hashtable of congruence classes */
602 hash_table
<congruence_class_group_hash
> m_classes
;
604 /* Count of congruence classes. */
605 unsigned int m_classes_count
;
607 /* Map data structure maps symtab nodes to semantic items. */
608 hash_map
<symtab_node
*, sem_item
*> m_symtab_node_map
;
610 /* Set to true if a splitter class is removed. */
611 bool splitter_class_removed
;
613 /* Global unique class id counter. */
614 static unsigned int class_id
;
616 /* Callgraph node removal hook holder. */
617 cgraph_node_hook_list
*m_cgraph_node_hooks
;
619 /* Varpool node removal hook holder. */
620 varpool_node_hook_list
*m_varpool_node_hooks
;
623 bitmap_obstack m_bmstack
;
624 }; // class sem_item_optimizer
626 } // ipa_icf namespace