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b84d4347 ML |
1 | /* Interprocedural semantic function equality pass |
2 | Copyright (C) 2014 Free Software Foundation, Inc. | |
3 | ||
4 | Contributed by Jan Hubicka <hubicka@ucw.cz> and Martin Liska <mliska@suse.cz> | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
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 | |
11 | version. | |
12 | ||
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 | |
16 | for more details. | |
17 | ||
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/>. */ | |
21 | ||
22 | namespace ipa_icf { | |
23 | class 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. */ | |
28 | class congruence_class | |
29 | { | |
30 | public: | |
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. */ | |
60 | enum sem_item_type | |
61 | { | |
62 | FUNC, | |
63 | VAR | |
64 | }; | |
65 | ||
66 | /* Semantic item usage pair. */ | |
67 | class sem_usage_pair | |
68 | { | |
69 | public: | |
70 | /* Constructor for key value pair, where _ITEM is key and _INDEX is a target. */ | |
71 | sem_usage_pair (sem_item *_item, unsigned int _index); | |
72 | ||
73 | /* Target semantic item where an item is used. */ | |
74 | sem_item *item; | |
75 | ||
76 | /* Index of usage of such an item. */ | |
77 | unsigned int index; | |
78 | }; | |
79 | ||
80 | /* Semantic item is a base class that encapsulates all shared functionality | |
81 | for both semantic function and variable items. */ | |
82 | class sem_item | |
83 | { | |
84 | public: | |
85 | /* Semantic item constructor for a node of _TYPE, where STACK is used | |
86 | for bitmap memory allocation. */ | |
87 | sem_item (sem_item_type _type, bitmap_obstack *stack); | |
88 | ||
89 | /* Semantic item constructor for a node of _TYPE, where STACK is used | |
90 | for bitmap memory allocation. The item is based on symtab node _NODE | |
91 | with computed _HASH. */ | |
92 | sem_item (sem_item_type _type, symtab_node *_node, hashval_t _hash, | |
93 | bitmap_obstack *stack); | |
94 | ||
95 | virtual ~sem_item (); | |
96 | ||
97 | /* Dump function for debugging purpose. */ | |
98 | DEBUG_FUNCTION void dump (void); | |
99 | ||
100 | /* Initialize semantic item by info reachable during LTO WPA phase. */ | |
101 | virtual void init_wpa (void) = 0; | |
102 | ||
103 | /* Semantic item initialization function. */ | |
104 | virtual void init (void) = 0; | |
105 | ||
106 | /* Add reference to a semantic TARGET. */ | |
107 | void add_reference (sem_item *target); | |
108 | ||
109 | /* Gets symbol name of the item. */ | |
110 | const char *name (void) | |
111 | { | |
112 | return node->name (); | |
113 | } | |
114 | ||
115 | /* Gets assembler name of the item. */ | |
116 | const char *asm_name (void) | |
117 | { | |
118 | return node->asm_name (); | |
119 | } | |
120 | ||
121 | /* Fast equality function based on knowledge known in WPA. */ | |
122 | virtual bool equals_wpa (sem_item *item, | |
123 | hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0; | |
124 | ||
125 | /* Returns true if the item equals to ITEM given as arguemnt. */ | |
126 | virtual bool equals (sem_item *item, | |
127 | hash_map <symtab_node *, sem_item *> &ignored_nodes) = 0; | |
128 | ||
129 | /* References independent hash function. */ | |
130 | virtual hashval_t get_hash (void) = 0; | |
131 | ||
132 | /* Merges instance with an ALIAS_ITEM, where alias, thunk or redirection can | |
133 | be applied. */ | |
134 | virtual bool merge (sem_item *alias_item) = 0; | |
135 | ||
136 | /* Dump symbol to FILE. */ | |
137 | virtual void dump_to_file (FILE *file) = 0; | |
138 | ||
139 | /* Return base tree that can be used for compatible_types_p and | |
140 | contains_polymorphic_type_p comparison. */ | |
141 | ||
142 | static bool get_base_types (tree *t1, tree *t2); | |
143 | ||
144 | /* Item type. */ | |
145 | sem_item_type type; | |
146 | ||
147 | /* Symtab node. */ | |
148 | symtab_node *node; | |
149 | ||
150 | /* Declaration tree node. */ | |
151 | tree decl; | |
152 | ||
153 | /* Semantic references used that generate congruence groups. */ | |
154 | vec <sem_item *> refs; | |
155 | ||
156 | /* Pointer to a congruence class the item belongs to. */ | |
157 | congruence_class *cls; | |
158 | ||
159 | /* Index of the item in a class belonging to. */ | |
160 | unsigned int index_in_class; | |
161 | ||
162 | /* List of semantic items where the instance is used. */ | |
163 | vec <sem_usage_pair *> usages; | |
164 | ||
165 | /* A bitmap with indices of all classes referencing this item. */ | |
166 | bitmap usage_index_bitmap; | |
167 | ||
168 | /* List of tree references (either FUNC_DECL or VAR_DECL). */ | |
169 | vec <tree> tree_refs; | |
170 | ||
171 | /* A set with symbol table references. */ | |
172 | hash_set <symtab_node *> refs_set; | |
173 | ||
174 | protected: | |
175 | /* Cached, once calculated hash for the item. */ | |
176 | hashval_t hash; | |
177 | ||
178 | private: | |
179 | /* Initialize internal data structures. Bitmap STACK is used for | |
180 | bitmap memory allocation process. */ | |
181 | void setup (bitmap_obstack *stack); | |
182 | }; // class sem_item | |
183 | ||
184 | class sem_function: public sem_item | |
185 | { | |
186 | public: | |
187 | /* Semantic function constructor that uses STACK as bitmap memory stack. */ | |
188 | sem_function (bitmap_obstack *stack); | |
189 | ||
190 | /* Constructor based on callgraph node _NODE with computed hash _HASH. | |
191 | Bitmap STACK is used for memory allocation. */ | |
192 | sem_function (cgraph_node *_node, hashval_t _hash, bitmap_obstack *stack); | |
193 | ||
194 | ~sem_function (); | |
195 | ||
196 | inline virtual void init_wpa (void) | |
197 | { | |
198 | parse_tree_args (); | |
199 | } | |
200 | ||
201 | virtual void init (void); | |
202 | virtual bool equals_wpa (sem_item *item, | |
203 | hash_map <symtab_node *, sem_item *> &ignored_nodes); | |
204 | virtual hashval_t get_hash (void); | |
205 | virtual bool equals (sem_item *item, | |
206 | hash_map <symtab_node *, sem_item *> &ignored_nodes); | |
207 | virtual bool merge (sem_item *alias_item); | |
208 | ||
209 | /* Dump symbol to FILE. */ | |
210 | virtual void dump_to_file (FILE *file) | |
211 | { | |
212 | gcc_assert (file); | |
213 | dump_function_to_file (decl, file, TDF_DETAILS); | |
214 | } | |
215 | ||
216 | /* Parses function arguments and result type. */ | |
217 | void parse_tree_args (void); | |
218 | ||
219 | /* Returns cgraph_node. */ | |
220 | inline cgraph_node *get_node (void) | |
221 | { | |
222 | return dyn_cast <cgraph_node *> (node); | |
223 | } | |
224 | ||
225 | /* Improve accumulated hash for HSTATE based on a gimple statement STMT. */ | |
226 | void hash_stmt (inchash::hash *inchash, gimple stmt); | |
227 | ||
228 | /* Return true if polymorphic comparison must be processed. */ | |
229 | bool compare_polymorphic_p (void); | |
230 | ||
231 | /* For a given call graph NODE, the function constructs new | |
232 | semantic function item. */ | |
233 | static sem_function *parse (cgraph_node *node, bitmap_obstack *stack); | |
234 | ||
235 | /* Exception handling region tree. */ | |
236 | eh_region region_tree; | |
237 | ||
238 | /* Result type tree node. */ | |
239 | tree result_type; | |
240 | ||
241 | /* Array of argument tree types. */ | |
242 | vec <tree> arg_types; | |
243 | ||
244 | /* Number of function arguments. */ | |
245 | unsigned int arg_count; | |
246 | ||
247 | /* Total amount of edges in the function. */ | |
248 | unsigned int edge_count; | |
249 | ||
250 | /* Vector of sizes of all basic blocks. */ | |
251 | vec <unsigned int> bb_sizes; | |
252 | ||
253 | /* Control flow graph checksum. */ | |
254 | hashval_t cfg_checksum; | |
255 | ||
256 | /* GIMPLE codes hash value. */ | |
257 | hashval_t gcode_hash; | |
258 | ||
259 | /* Total number of SSA names used in the function. */ | |
260 | unsigned ssa_names_size; | |
261 | ||
262 | /* Array of structures for all basic blocks. */ | |
263 | vec <ipa_icf_gimple::sem_bb *> bb_sorted; | |
264 | ||
265 | private: | |
266 | /* Calculates hash value based on a BASIC_BLOCK. */ | |
267 | hashval_t get_bb_hash (const ipa_icf_gimple::sem_bb *basic_block); | |
268 | ||
269 | /* For given basic blocks BB1 and BB2 (from functions FUNC1 and FUNC), | |
270 | true value is returned if phi nodes are semantically | |
271 | equivalent in these blocks . */ | |
272 | bool compare_phi_node (basic_block bb1, basic_block bb2); | |
273 | ||
274 | /* Basic blocks dictionary BB_DICT returns true if SOURCE index BB | |
275 | corresponds to TARGET. */ | |
276 | bool bb_dict_test (int* bb_dict, int source, int target); | |
277 | ||
278 | /* Iterates all tree types in T1 and T2 and returns true if all types | |
279 | are compatible. If COMPARE_POLYMORPHIC is set to true, | |
280 | more strict comparison is executed. */ | |
281 | bool compare_type_list (tree t1, tree t2, bool compare_polymorphic); | |
282 | ||
283 | /* If cgraph edges E1 and E2 are indirect calls, verify that | |
284 | ICF flags are the same. */ | |
285 | bool compare_edge_flags (cgraph_edge *e1, cgraph_edge *e2); | |
286 | ||
287 | /* For a given symbol table nodes N1 and N2, we check that FUNCTION_DECLs | |
288 | point to a same function. Comparison can be skipped if IGNORED_NODES | |
289 | contains these nodes. */ | |
290 | bool compare_cgraph_references (hash_map <symtab_node *, sem_item *> | |
291 | &ignored_nodes, | |
292 | symtab_node *n1, symtab_node *n2); | |
293 | ||
294 | /* Processes function equality comparison. */ | |
295 | bool equals_private (sem_item *item, | |
296 | hash_map <symtab_node *, sem_item *> &ignored_nodes); | |
297 | ||
298 | /* Returns true if tree T can be compared as a handled component. */ | |
299 | static bool icf_handled_component_p (tree t); | |
300 | ||
301 | /* Function checker stores binding between functions. */ | |
302 | ipa_icf_gimple::func_checker *m_checker; | |
303 | ||
304 | /* COMPARED_FUNC is a function that we compare to. */ | |
305 | sem_function *m_compared_func; | |
306 | }; // class sem_function | |
307 | ||
308 | class sem_variable: public sem_item | |
309 | { | |
310 | public: | |
311 | /* Semantic variable constructor that uses STACK as bitmap memory stack. */ | |
312 | sem_variable (bitmap_obstack *stack); | |
313 | ||
314 | /* Constructor based on callgraph node _NODE with computed hash _HASH. | |
315 | Bitmap STACK is used for memory allocation. */ | |
316 | ||
317 | sem_variable (varpool_node *_node, hashval_t _hash, bitmap_obstack *stack); | |
318 | ||
319 | inline virtual void init_wpa (void) {} | |
320 | ||
321 | /* Semantic variable initialization function. */ | |
322 | inline virtual void init (void) | |
323 | { | |
324 | decl = get_node ()->decl; | |
325 | ctor = ctor_for_folding (decl); | |
326 | } | |
327 | ||
328 | virtual hashval_t get_hash (void); | |
329 | virtual bool merge (sem_item *alias_item); | |
330 | virtual void dump_to_file (FILE *file); | |
331 | virtual bool equals (sem_item *item, | |
332 | hash_map <symtab_node *, sem_item *> &ignored_nodes); | |
333 | ||
334 | /* Fast equality variable based on knowledge known in WPA. */ | |
335 | inline virtual bool equals_wpa (sem_item *item, | |
336 | hash_map <symtab_node *, sem_item *> & ARG_UNUSED(ignored_nodes)) | |
337 | { | |
338 | gcc_assert (item->type == VAR); | |
339 | return true; | |
340 | } | |
341 | ||
342 | /* Returns varpool_node. */ | |
343 | inline varpool_node *get_node (void) | |
344 | { | |
345 | return dyn_cast <varpool_node *> (node); | |
346 | } | |
347 | ||
348 | /* Parser function that visits a varpool NODE. */ | |
349 | static sem_variable *parse (varpool_node *node, bitmap_obstack *stack); | |
350 | ||
351 | /* Variable constructor. */ | |
352 | tree ctor; | |
353 | ||
354 | private: | |
355 | /* Iterates though a constructor and identifies tree references | |
356 | we are interested in semantic function equality. */ | |
357 | void parse_tree_refs (tree t); | |
358 | ||
359 | /* Compares trees T1 and T2 for semantic equality. */ | |
360 | static bool equals (tree t1, tree t2); | |
361 | ||
362 | /* Compare that symbol sections are either NULL or have same name. */ | |
363 | bool compare_sections (sem_variable *alias); | |
364 | ||
365 | }; // class sem_variable | |
366 | ||
367 | class sem_item_optimizer; | |
368 | ||
369 | struct congruence_class_group | |
370 | { | |
371 | hashval_t hash; | |
372 | sem_item_type type; | |
373 | vec <congruence_class *> classes; | |
374 | }; | |
375 | ||
376 | /* Congruence class set structure. */ | |
377 | struct congruence_class_group_hash: typed_noop_remove <congruence_class_group> | |
378 | { | |
379 | typedef congruence_class_group value_type; | |
380 | typedef congruence_class_group compare_type; | |
381 | ||
382 | static inline hashval_t hash (const value_type *item) | |
383 | { | |
384 | return item->hash; | |
385 | } | |
386 | ||
387 | static inline int equal (const value_type *item1, const compare_type *item2) | |
388 | { | |
389 | return item1->hash == item2->hash && item1->type == item2->type; | |
390 | } | |
391 | }; | |
392 | ||
393 | struct traverse_split_pair | |
394 | { | |
395 | sem_item_optimizer *optimizer; | |
396 | class congruence_class *cls; | |
397 | }; | |
398 | ||
399 | /* Semantic item optimizer includes all top-level logic | |
400 | related to semantic equality comparison. */ | |
401 | class sem_item_optimizer | |
402 | { | |
403 | public: | |
404 | sem_item_optimizer (); | |
405 | ~sem_item_optimizer (); | |
406 | ||
407 | /* Function responsible for visiting all potential functions and | |
408 | read-only variables that can be merged. */ | |
409 | void parse_funcs_and_vars (void); | |
410 | ||
411 | /* Optimizer entry point. */ | |
412 | void execute (void); | |
413 | ||
414 | /* Dump function. */ | |
415 | void dump (void); | |
416 | ||
417 | /* Verify congruence classes if checking is enabled. */ | |
418 | void verify_classes (void); | |
419 | ||
420 | /* Write IPA ICF summary for symbols. */ | |
421 | void write_summary (void); | |
422 | ||
423 | /* Read IPA IPA ICF summary for symbols. */ | |
424 | void read_summary (void); | |
425 | ||
426 | /* Callgraph removal hook called for a NODE with a custom DATA. */ | |
427 | static void cgraph_removal_hook (cgraph_node *node, void *data); | |
428 | ||
429 | /* Varpool removal hook called for a NODE with a custom DATA. */ | |
430 | static void varpool_removal_hook (varpool_node *node, void *data); | |
431 | ||
432 | /* Worklist of congruence classes that can potentially | |
433 | refine classes of congruence. */ | |
434 | std::list<congruence_class *> worklist; | |
435 | ||
436 | /* Remove semantic ITEM and release memory. */ | |
437 | void remove_item (sem_item *item); | |
438 | ||
439 | /* Remove symtab NODE triggered by symtab removal hooks. */ | |
440 | void remove_symtab_node (symtab_node *node); | |
441 | ||
442 | /* Register callgraph and varpool hooks. */ | |
443 | void register_hooks (void); | |
444 | ||
445 | /* Unregister callgraph and varpool hooks. */ | |
446 | void unregister_hooks (void); | |
447 | ||
448 | /* Adds a CLS to hashtable associated by hash value. */ | |
449 | void add_class (congruence_class *cls); | |
450 | ||
451 | /* Gets a congruence class group based on given HASH value and TYPE. */ | |
452 | congruence_class_group *get_group_by_hash (hashval_t hash, | |
453 | sem_item_type type); | |
454 | ||
455 | private: | |
456 | ||
457 | /* Congruence classes are built by hash value. */ | |
458 | void build_hash_based_classes (void); | |
459 | ||
460 | /* Semantic items in classes having more than one element and initialized. | |
461 | In case of WPA, we load function body. */ | |
462 | void parse_nonsingleton_classes (void); | |
463 | ||
464 | /* Equality function for semantic items is used to subdivide existing | |
465 | classes. If IN_WPA, fast equality function is invoked. */ | |
466 | void subdivide_classes_by_equality (bool in_wpa = false); | |
467 | ||
468 | /* Debug function prints all informations about congruence classes. */ | |
469 | void dump_cong_classes (void); | |
470 | ||
471 | /* Build references according to call graph. */ | |
472 | void build_graph (void); | |
473 | ||
474 | /* Iterative congruence reduction function. */ | |
475 | void process_cong_reduction (void); | |
476 | ||
477 | /* After reduction is done, we can declare all items in a group | |
478 | to be equal. PREV_CLASS_COUNT is start number of classes | |
479 | before reduction. */ | |
480 | void merge_classes (unsigned int prev_class_count); | |
481 | ||
482 | /* Adds a newly created congruence class CLS to worklist. */ | |
483 | void worklist_push (congruence_class *cls); | |
484 | ||
485 | /* Pops a class from worklist. */ | |
486 | congruence_class *worklist_pop (); | |
487 | ||
488 | /* Every usage of a congruence class CLS is a candidate that can split the | |
489 | collection of classes. Bitmap stack BMSTACK is used for bitmap | |
490 | allocation. */ | |
491 | void do_congruence_step (congruence_class *cls); | |
492 | ||
493 | /* Tests if a class CLS used as INDEXth splits any congruence classes. | |
494 | Bitmap stack BMSTACK is used for bitmap allocation. */ | |
495 | void do_congruence_step_for_index (congruence_class *cls, unsigned int index); | |
496 | ||
497 | /* Makes pairing between a congruence class CLS and semantic ITEM. */ | |
498 | static void add_item_to_class (congruence_class *cls, sem_item *item); | |
499 | ||
500 | /* Disposes split map traverse function. CLS is congruence | |
501 | class, BSLOT is bitmap slot we want to release. DATA is mandatory, | |
502 | but unused argument. */ | |
503 | static bool release_split_map (congruence_class * const &cls, bitmap const &b, | |
504 | traverse_split_pair *pair); | |
505 | ||
506 | /* Process split operation for a cognruence class CLS, | |
507 | where bitmap B splits congruence class members. DATA is used | |
508 | as argument of split pair. */ | |
509 | static bool traverse_congruence_split (congruence_class * const &cls, | |
510 | bitmap const &b, | |
511 | traverse_split_pair *pair); | |
512 | ||
513 | /* Reads a section from LTO stream file FILE_DATA. Input block for DATA | |
514 | contains LEN bytes. */ | |
515 | void read_section (lto_file_decl_data *file_data, const char *data, | |
516 | size_t len); | |
517 | ||
518 | /* Removes all callgraph and varpool nodes that are marked by symtab | |
519 | as deleted. */ | |
520 | void filter_removed_items (void); | |
521 | ||
522 | /* Vector of semantic items. */ | |
523 | vec <sem_item *> m_items; | |
524 | ||
525 | /* A set containing all items removed by hooks. */ | |
526 | hash_set <symtab_node *> m_removed_items_set; | |
527 | ||
528 | /* Hashtable of congruence classes */ | |
529 | hash_table <congruence_class_group_hash> m_classes; | |
530 | ||
531 | /* Count of congruence classes. */ | |
532 | unsigned int m_classes_count; | |
533 | ||
534 | /* Map data structure maps symtab nodes to semantic items. */ | |
535 | hash_map <symtab_node *, sem_item *> m_symtab_node_map; | |
536 | ||
537 | /* Set to true if a splitter class is removed. */ | |
538 | bool splitter_class_removed; | |
539 | ||
540 | /* Global unique class id counter. */ | |
541 | static unsigned int class_id; | |
542 | ||
543 | /* Callgraph node removal hook holder. */ | |
544 | cgraph_node_hook_list *m_cgraph_node_hooks; | |
545 | ||
546 | /* Varpool node removal hook holder. */ | |
547 | varpool_node_hook_list *m_varpool_node_hooks; | |
548 | ||
549 | /* Bitmap stack. */ | |
550 | bitmap_obstack m_bmstack; | |
551 | }; // class sem_item_optimizer | |
552 | ||
553 | } // ipa_icf namespace |