Update gcc-50 to SVN version 221572
[dragonfly.git] / contrib / gcc-5.0 / gcc / ipa-icf.h
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1/* Interprocedural semantic function equality pass
2 Copyright (C) 2014-2015 Free Software Foundation, Inc.
3
4 Contributed by Jan Hubicka <hubicka@ucw.cz> and Martin Liska <mliska@suse.cz>
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 3, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
21
22namespace ipa_icf {
23class sem_item;
24
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. */
28class congruence_class
29{
30public:
31 /* Congruence class constructor for a new class with _ID. */
32 congruence_class (unsigned int _id): in_worklist (false), id(_id)
33 {
34 }
35
36 /* Destructor. */
37 ~congruence_class ()
38 {
39 }
40
41 /* Dump function prints all class members to a FILE with an INDENT. */
42 void dump (FILE *file, unsigned int indent = 0) const;
43
44 /* Returns true if there's a member that is used from another group. */
45 bool is_class_used (void);
46
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). */
50 bool in_worklist;
51
52 /* Vector of all group members. */
53 auto_vec <sem_item *> members;
54
55 /* Global unique class identifier. */
56 unsigned int id;
57};
58
59/* Semantic item type enum. */
60enum sem_item_type
61{
62 FUNC,
63 VAR
64};
65
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66/* Class is container for address references for a symtab_node. */
67
68class symbol_compare_collection
69{
70public:
71 /* Constructor. */
72 symbol_compare_collection (symtab_node *node);
73
74 /* Destructor. */
75 ~symbol_compare_collection ()
76 {
77 m_references.release ();
78 m_interposables.release ();
79 }
80
81 /* Vector of address references. */
82 vec<symtab_node *> m_references;
83
84 /* Vector of interposable references. */
85 vec<symtab_node *> m_interposables;
86};
87
88/* Hash traits for symbol_compare_collection map. */
89
90struct symbol_compare_hashmap_traits: default_hashmap_traits
91{
92 static hashval_t
93 hash (const symbol_compare_collection *v)
94 {
95 inchash::hash hstate;
96 hstate.add_int (v->m_references.length ());
97
98 for (unsigned i = 0; i < v->m_references.length (); i++)
99 hstate.add_ptr (v->m_references[i]->ultimate_alias_target ());
100
101 hstate.add_int (v->m_interposables.length ());
102
103 for (unsigned i = 0; i < v->m_interposables.length (); i++)
104 hstate.add_ptr (v->m_interposables[i]->ultimate_alias_target ());
105
106 return hstate.end ();
107 }
108
109 static bool
110 equal_keys (const symbol_compare_collection *a,
111 const symbol_compare_collection *b)
112 {
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113 if (a->m_references.length () != b->m_references.length ()
114 || a->m_interposables.length () != b->m_interposables.length ())
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115 return false;
116
117 for (unsigned i = 0; i < a->m_references.length (); i++)
118 if (a->m_references[i]->equal_address_to (b->m_references[i]) != 1)
119 return false;
120
121 for (unsigned i = 0; i < a->m_interposables.length (); i++)
122 if (!a->m_interposables[i]->semantically_equivalent_p
123 (b->m_interposables[i]))
124 return false;
125
126 return true;
127 }
128};
129
130
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131/* Semantic item usage pair. */
132class sem_usage_pair
133{
134public:
135 /* Constructor for key value pair, where _ITEM is key and _INDEX is a target. */
136 sem_usage_pair (sem_item *_item, unsigned int _index);
137
138 /* Target semantic item where an item is used. */
139 sem_item *item;
140
141 /* Index of usage of such an item. */
142 unsigned int index;
143};
144
145/* Semantic item is a base class that encapsulates all shared functionality
146 for both semantic function and variable items. */
147class sem_item
148{
149public:
150 /* Semantic item constructor for a node of _TYPE, where STACK is used
151 for bitmap memory allocation. */
152 sem_item (sem_item_type _type, bitmap_obstack *stack);
153
154 /* Semantic item constructor for a node of _TYPE, where STACK is used
155 for bitmap memory allocation. The item is based on symtab node _NODE
156 with computed _HASH. */
157 sem_item (sem_item_type _type, symtab_node *_node, hashval_t _hash,
158 bitmap_obstack *stack);
159
160 virtual ~sem_item ();
161
162 /* Dump function for debugging purpose. */
163 DEBUG_FUNCTION void dump (void);
164
165 /* Initialize semantic item by info reachable during LTO WPA phase. */
166 virtual void init_wpa (void) = 0;
167
168 /* Semantic item initialization function. */
169 virtual void init (void) = 0;
170
171 /* Add reference to a semantic TARGET. */
172 void add_reference (sem_item *target);
173
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174 /* Fast equality function based on knowledge known in WPA. */
175 virtual bool equals_wpa (sem_item *item,
176 hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0;
177
178 /* Returns true if the item equals to ITEM given as arguemnt. */
179 virtual bool equals (sem_item *item,
180 hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0;
181
182 /* References independent hash function. */
183 virtual hashval_t get_hash (void) = 0;
184
185 /* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can
186 be applied. */
187 virtual bool merge (sem_item *alias_item) = 0;
188
189 /* Dump symbol to FILE. */
190 virtual void dump_to_file (FILE *file) = 0;
191
192 /* Return base tree that can be used for compatible_types_p and
193 contains_polymorphic_type_p comparison. */
194 static bool get_base_types (tree *t1, tree *t2);
195
196 /* Return true if target supports alias symbols. */
197 bool target_supports_symbol_aliases_p (void);
198
199 /* Item type. */
200 sem_item_type type;
201
202 /* Symtab node. */
203 symtab_node *node;
204
205 /* Declaration tree node. */
206 tree decl;
207
208 /* Semantic references used that generate congruence groups. */
209 vec <sem_item *> refs;
210
211 /* Pointer to a congruence class the item belongs to. */
212 congruence_class *cls;
213
214 /* Index of the item in a class belonging to. */
215 unsigned int index_in_class;
216
217 /* List of semantic items where the instance is used. */
218 vec <sem_usage_pair *> usages;
219
220 /* A bitmap with indices of all classes referencing this item. */
221 bitmap usage_index_bitmap;
222
223 /* List of tree references (either FUNC_DECL or VAR_DECL). */
224 vec <tree> tree_refs;
225
226 /* A set with symbol table references. */
227 hash_set <symtab_node *> refs_set;
228
229protected:
230 /* Cached, once calculated hash for the item. */
231 hashval_t hash;
232
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233 /* Accumulate to HSTATE a hash of constructor expression EXP. */
234 static void add_expr (const_tree exp, inchash::hash &hstate);
235
236 /* For a given symbol table nodes N1 and N2, we check that FUNCTION_DECLs
237 point to a same function. Comparison can be skipped if IGNORED_NODES
238 contains these nodes. ADDRESS indicate if address is taken. */
239 bool compare_cgraph_references (hash_map <symtab_node *, sem_item *>
240 &ignored_nodes,
241 symtab_node *n1, symtab_node *n2,
242 bool address);
243
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244private:
245 /* Initialize internal data structures. Bitmap STACK is used for
246 bitmap memory allocation process. */
247 void setup (bitmap_obstack *stack);
248}; // class sem_item
249
250class sem_function: public sem_item
251{
252public:
253 /* Semantic function constructor that uses STACK as bitmap memory stack. */
254 sem_function (bitmap_obstack *stack);
255
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);
259
260 ~sem_function ();
261
262 inline virtual void init_wpa (void)
263 {
264 parse_tree_args ();
265 }
266
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);
274
275 /* Dump symbol to FILE. */
276 virtual void dump_to_file (FILE *file)
277 {
278 gcc_assert (file);
279 dump_function_to_file (decl, file, TDF_DETAILS);
280 }
281
282 /* Parses function arguments and result type. */
283 void parse_tree_args (void);
284
285 /* Returns cgraph_node. */
286 inline cgraph_node *get_node (void)
287 {
288 return dyn_cast <cgraph_node *> (node);
289 }
290
291 /* Improve accumulated hash for HSTATE based on a gimple statement STMT. */
7de7a9db 292 void hash_stmt (gimple stmt, inchash::hash &inchash);
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293
294 /* Return true if polymorphic comparison must be processed. */
295 bool compare_polymorphic_p (void);
296
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);
300
301 /* Exception handling region tree. */
302 eh_region region_tree;
303
304 /* Result type tree node. */
305 tree result_type;
306
307 /* Array of argument tree types. */
308 vec <tree> arg_types;
309
310 /* Number of function arguments. */
311 unsigned int arg_count;
312
313 /* Total amount of edges in the function. */
314 unsigned int edge_count;
315
316 /* Vector of sizes of all basic blocks. */
317 vec <unsigned int> bb_sizes;
318
319 /* Control flow graph checksum. */
320 hashval_t cfg_checksum;
321
322 /* GIMPLE codes hash value. */
323 hashval_t gcode_hash;
324
325 /* Total number of SSA names used in the function. */
326 unsigned ssa_names_size;
327
328 /* Array of structures for all basic blocks. */
329 vec <ipa_icf_gimple::sem_bb *> bb_sorted;
330
331private:
332 /* Calculates hash value based on a BASIC_BLOCK. */
333 hashval_t get_bb_hash (const ipa_icf_gimple::sem_bb *basic_block);
334
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);
339
340 /* Basic blocks dictionary BB_DICT returns true if SOURCE index BB
341 corresponds to TARGET. */
f4d9d362 342 bool bb_dict_test (vec<int> *bb_dict, int source, int target);
dda118e3 343
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344 /* If cgraph edges E1 and E2 are indirect calls, verify that
345 ICF flags are the same. */
346 bool compare_edge_flags (cgraph_edge *e1, cgraph_edge *e2);
347
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348 /* Processes function equality comparison. */
349 bool equals_private (sem_item *item,
350 hash_map <symtab_node *, sem_item *> &ignored_nodes);
351
352 /* Returns true if tree T can be compared as a handled component. */
353 static bool icf_handled_component_p (tree t);
354
355 /* Function checker stores binding between functions. */
356 ipa_icf_gimple::func_checker *m_checker;
357
358 /* COMPARED_FUNC is a function that we compare to. */
359 sem_function *m_compared_func;
360}; // class sem_function
361
362class sem_variable: public sem_item
363{
364public:
365 /* Semantic variable constructor that uses STACK as bitmap memory stack. */
366 sem_variable (bitmap_obstack *stack);
367
368 /* Constructor based on callgraph node _NODE with computed hash _HASH.
369 Bitmap STACK is used for memory allocation. */
370
371 sem_variable (varpool_node *_node, hashval_t _hash, bitmap_obstack *stack);
372
373 inline virtual void init_wpa (void) {}
374
375 /* Semantic variable initialization function. */
376 inline virtual void init (void)
377 {
378 decl = get_node ()->decl;
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379 }
380
381 virtual hashval_t get_hash (void);
382 virtual bool merge (sem_item *alias_item);
383 virtual void dump_to_file (FILE *file);
384 virtual bool equals (sem_item *item,
385 hash_map <symtab_node *, sem_item *> &ignored_nodes);
386
387 /* Fast equality variable based on knowledge known in WPA. */
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388 virtual bool equals_wpa (sem_item *item,
389 hash_map <symtab_node *, sem_item *> &ignored_nodes);
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390
391 /* Returns varpool_node. */
392 inline varpool_node *get_node (void)
393 {
394 return dyn_cast <varpool_node *> (node);
395 }
396
397 /* Parser function that visits a varpool NODE. */
398 static sem_variable *parse (varpool_node *node, bitmap_obstack *stack);
399
dda118e3 400private:
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401 /* Compares trees T1 and T2 for semantic equality. */
402 static bool equals (tree t1, tree t2);
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403}; // class sem_variable
404
405class sem_item_optimizer;
406
407struct congruence_class_group
408{
409 hashval_t hash;
410 sem_item_type type;
411 vec <congruence_class *> classes;
412};
413
414/* Congruence class set structure. */
415struct congruence_class_group_hash: typed_noop_remove <congruence_class_group>
416{
417 typedef congruence_class_group value_type;
418 typedef congruence_class_group compare_type;
419
420 static inline hashval_t hash (const value_type *item)
421 {
422 return item->hash;
423 }
424
425 static inline int equal (const value_type *item1, const compare_type *item2)
426 {
427 return item1->hash == item2->hash && item1->type == item2->type;
428 }
429};
430
431struct traverse_split_pair
432{
433 sem_item_optimizer *optimizer;
434 class congruence_class *cls;
435};
436
437/* Semantic item optimizer includes all top-level logic
438 related to semantic equality comparison. */
439class sem_item_optimizer
440{
441public:
442 sem_item_optimizer ();
443 ~sem_item_optimizer ();
444
445 /* Function responsible for visiting all potential functions and
446 read-only variables that can be merged. */
447 void parse_funcs_and_vars (void);
448
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449 /* Optimizer entry point which returns true in case it processes
450 a merge operation. True is returned if there's a merge operation
451 processed. */
452 bool execute (void);
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453
454 /* Dump function. */
455 void dump (void);
456
457 /* Verify congruence classes if checking is enabled. */
458 void verify_classes (void);
459
460 /* Write IPA ICF summary for symbols. */
461 void write_summary (void);
462
463 /* Read IPA IPA ICF summary for symbols. */
464 void read_summary (void);
465
466 /* Callgraph removal hook called for a NODE with a custom DATA. */
467 static void cgraph_removal_hook (cgraph_node *node, void *data);
468
469 /* Varpool removal hook called for a NODE with a custom DATA. */
470 static void varpool_removal_hook (varpool_node *node, void *data);
471
472 /* Worklist of congruence classes that can potentially
473 refine classes of congruence. */
474 std::list<congruence_class *> worklist;
475
476 /* Remove semantic ITEM and release memory. */
477 void remove_item (sem_item *item);
478
479 /* Remove symtab NODE triggered by symtab removal hooks. */
480 void remove_symtab_node (symtab_node *node);
481
482 /* Register callgraph and varpool hooks. */
483 void register_hooks (void);
484
485 /* Unregister callgraph and varpool hooks. */
486 void unregister_hooks (void);
487
488 /* Adds a CLS to hashtable associated by hash value. */
489 void add_class (congruence_class *cls);
490
491 /* Gets a congruence class group based on given HASH value and TYPE. */
492 congruence_class_group *get_group_by_hash (hashval_t hash,
493 sem_item_type type);
494
495private:
496
497 /* Congruence classes are built by hash value. */
498 void build_hash_based_classes (void);
499
500 /* Semantic items in classes having more than one element and initialized.
501 In case of WPA, we load function body. */
502 void parse_nonsingleton_classes (void);
503
504 /* Equality function for semantic items is used to subdivide existing
505 classes. If IN_WPA, fast equality function is invoked. */
506 void subdivide_classes_by_equality (bool in_wpa = false);
507
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508 /* Subdivide classes by address and interposable references
509 that members of the class reference.
510 Example can be a pair of functions that have an address
511 taken from a function. If these addresses are different the class
512 is split. */
513 unsigned subdivide_classes_by_sensitive_refs();
514
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515 /* Debug function prints all informations about congruence classes. */
516 void dump_cong_classes (void);
517
518 /* Build references according to call graph. */
519 void build_graph (void);
520
521 /* Iterative congruence reduction function. */
522 void process_cong_reduction (void);
523
524 /* After reduction is done, we can declare all items in a group
525 to be equal. PREV_CLASS_COUNT is start number of classes
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526 before reduction. True is returned if there's a merge operation
527 processed. */
528 bool merge_classes (unsigned int prev_class_count);
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529
530 /* Adds a newly created congruence class CLS to worklist. */
531 void worklist_push (congruence_class *cls);
532
533 /* Pops a class from worklist. */
534 congruence_class *worklist_pop ();
535
536 /* Every usage of a congruence class CLS is a candidate that can split the
537 collection of classes. Bitmap stack BMSTACK is used for bitmap
538 allocation. */
539 void do_congruence_step (congruence_class *cls);
540
541 /* Tests if a class CLS used as INDEXth splits any congruence classes.
542 Bitmap stack BMSTACK is used for bitmap allocation. */
543 void do_congruence_step_for_index (congruence_class *cls, unsigned int index);
544
545 /* Makes pairing between a congruence class CLS and semantic ITEM. */
546 static void add_item_to_class (congruence_class *cls, sem_item *item);
547
548 /* Disposes split map traverse function. CLS is congruence
549 class, BSLOT is bitmap slot we want to release. DATA is mandatory,
550 but unused argument. */
551 static bool release_split_map (congruence_class * const &cls, bitmap const &b,
552 traverse_split_pair *pair);
553
554 /* Process split operation for a cognruence class CLS,
555 where bitmap B splits congruence class members. DATA is used
556 as argument of split pair. */
557 static bool traverse_congruence_split (congruence_class * const &cls,
558 bitmap const &b,
559 traverse_split_pair *pair);
560
561 /* Reads a section from LTO stream file FILE_DATA. Input block for DATA
562 contains LEN bytes. */
563 void read_section (lto_file_decl_data *file_data, const char *data,
564 size_t len);
565
566 /* Removes all callgraph and varpool nodes that are marked by symtab
567 as deleted. */
568 void filter_removed_items (void);
569
570 /* Vector of semantic items. */
571 vec <sem_item *> m_items;
572
573 /* A set containing all items removed by hooks. */
574 hash_set <symtab_node *> m_removed_items_set;
575
576 /* Hashtable of congruence classes */
577 hash_table <congruence_class_group_hash> m_classes;
578
579 /* Count of congruence classes. */
580 unsigned int m_classes_count;
581
582 /* Map data structure maps symtab nodes to semantic items. */
583 hash_map <symtab_node *, sem_item *> m_symtab_node_map;
584
585 /* Set to true if a splitter class is removed. */
586 bool splitter_class_removed;
587
588 /* Global unique class id counter. */
589 static unsigned int class_id;
590
591 /* Callgraph node removal hook holder. */
592 cgraph_node_hook_list *m_cgraph_node_hooks;
593
594 /* Varpool node removal hook holder. */
595 varpool_node_hook_list *m_varpool_node_hooks;
596
597 /* Bitmap stack. */
598 bitmap_obstack m_bmstack;
599}; // class sem_item_optimizer
600
601} // ipa_icf namespace