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4ee9c684 | 1 | /* Rewrite a program in Normal form into SSA. |
fbd26352 | 2 | Copyright (C) 2001-2019 Free Software Foundation, Inc. |
4ee9c684 | 3 | Contributed by Diego Novillo <dnovillo@redhat.com> |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify | |
8 | it under the terms of the GNU General Public License as published by | |
8c4c00c1 | 9 | the Free Software Foundation; either version 3, or (at your option) |
4ee9c684 | 10 | any later version. |
11 | ||
12 | GCC is distributed in the hope that it will be useful, | |
13 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | GNU General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ | |
4ee9c684 | 20 | |
21 | #include "config.h" | |
22 | #include "system.h" | |
23 | #include "coretypes.h" | |
9ef16211 | 24 | #include "backend.h" |
7c29e30e | 25 | #include "rtl.h" |
4ee9c684 | 26 | #include "tree.h" |
9ef16211 | 27 | #include "gimple.h" |
7c29e30e | 28 | #include "tree-pass.h" |
9ef16211 | 29 | #include "ssa.h" |
7c29e30e | 30 | #include "gimple-pretty-print.h" |
31 | #include "diagnostic-core.h" | |
4ee9c684 | 32 | #include "langhooks.h" |
94ea8568 | 33 | #include "cfganal.h" |
dcf1a1ec | 34 | #include "gimple-iterator.h" |
073c1fd5 | 35 | #include "tree-cfg.h" |
073c1fd5 | 36 | #include "tree-into-ssa.h" |
37 | #include "tree-dfa.h" | |
38 | #include "tree-ssa.h" | |
4ee9c684 | 39 | #include "domwalk.h" |
b35a87b1 | 40 | #include "statistics.h" |
30a86690 | 41 | #include "stringpool.h" |
42 | #include "attribs.h" | |
ba39c1d4 | 43 | #include "asan.h" |
4ee9c684 | 44 | |
e797f49f | 45 | #define PERCENT(x,y) ((float)(x) * 100.0 / (float)(y)) |
75a70cf9 | 46 | |
4ee9c684 | 47 | /* This file builds the SSA form for a function as described in: |
48 | R. Cytron, J. Ferrante, B. Rosen, M. Wegman, and K. Zadeck. Efficiently | |
49 | Computing Static Single Assignment Form and the Control Dependence | |
50 | Graph. ACM Transactions on Programming Languages and Systems, | |
51 | 13(4):451-490, October 1991. */ | |
52 | ||
4ee9c684 | 53 | /* Structure to map a variable VAR to the set of blocks that contain |
54 | definitions for VAR. */ | |
04009ada | 55 | struct def_blocks |
4ee9c684 | 56 | { |
4ee9c684 | 57 | /* Blocks that contain definitions of VAR. Bit I will be set if the |
58 | Ith block contains a definition of VAR. */ | |
59 | bitmap def_blocks; | |
60 | ||
e551bd1a | 61 | /* Blocks that contain a PHI node for VAR. */ |
f3d9a16c | 62 | bitmap phi_blocks; |
63 | ||
4ee9c684 | 64 | /* Blocks where VAR is live-on-entry. Similar semantics as |
65 | DEF_BLOCKS. */ | |
66 | bitmap livein_blocks; | |
67 | }; | |
68 | ||
dd2d357d | 69 | /* Stack of trees used to restore the global currdefs to its original |
88dbf20f | 70 | state after completing rewriting of a block and its dominator |
71 | children. Its elements have the following properties: | |
dd2d357d | 72 | |
4fb5e5ca | 73 | - An SSA_NAME (N) indicates that the current definition of the |
74 | underlying variable should be set to the given SSA_NAME. If the | |
75 | symbol associated with the SSA_NAME is not a GIMPLE register, the | |
76 | next slot in the stack must be a _DECL node (SYM). In this case, | |
77 | the name N in the previous slot is the current reaching | |
78 | definition for SYM. | |
dd2d357d | 79 | |
88dbf20f | 80 | - A _DECL node indicates that the underlying variable has no |
81 | current definition. | |
e551bd1a | 82 | |
4fb5e5ca | 83 | - A NULL node at the top entry is used to mark the last slot |
88dbf20f | 84 | associated with the current block. */ |
f1f41a6c | 85 | static vec<tree> block_defs_stack; |
486b57c7 | 86 | |
75a70cf9 | 87 | |
88dbf20f | 88 | /* Set of existing SSA names being replaced by update_ssa. */ |
89 | static sbitmap old_ssa_names; | |
90 | ||
91 | /* Set of new SSA names being added by update_ssa. Note that both | |
92 | NEW_SSA_NAMES and OLD_SSA_NAMES are dense bitmaps because most of | |
93 | the operations done on them are presence tests. */ | |
94 | static sbitmap new_ssa_names; | |
95 | ||
47c1894f | 96 | static sbitmap interesting_blocks; |
75a70cf9 | 97 | |
88dbf20f | 98 | /* Set of SSA names that have been marked to be released after they |
99 | were registered in the replacement table. They will be finally | |
100 | released after we finish updating the SSA web. */ | |
0b0b7c83 | 101 | bitmap names_to_release; |
88dbf20f | 102 | |
f1f41a6c | 103 | /* vec of vec of PHIs to rewrite in a basic block. Element I corresponds |
2670407e | 104 | the to basic block with index I. Allocated once per compilation, *not* |
105 | released between different functions. */ | |
1a91d914 | 106 | static vec< vec<gphi *> > phis_to_rewrite; |
70630fcd | 107 | |
108 | /* The bitmap of non-NULL elements of PHIS_TO_REWRITE. */ | |
70630fcd | 109 | static bitmap blocks_with_phis_to_rewrite; |
110 | ||
88dbf20f | 111 | /* Growth factor for NEW_SSA_NAMES and OLD_SSA_NAMES. These sets need |
0dc262e0 | 112 | to grow as the callers to create_new_def_for will create new names on |
113 | the fly. | |
114 | FIXME. Currently set to 1/3 to avoid frequent reallocations but still | |
115 | need to find a reasonable growth strategy. */ | |
88dbf20f | 116 | #define NAME_SETS_GROWTH_FACTOR (MAX (3, num_ssa_names / 3)) |
117 | ||
88dbf20f | 118 | |
dd277d48 | 119 | /* The function the SSA updating data structures have been initialized for. |
0dc262e0 | 120 | NULL if they need to be initialized by create_new_def_for. */ |
dd277d48 | 121 | static struct function *update_ssa_initialized_fn = NULL; |
88dbf20f | 122 | |
4ee9c684 | 123 | /* Global data to attach to the main dominator walk structure. */ |
124 | struct mark_def_sites_global_data | |
125 | { | |
88dbf20f | 126 | /* This bitmap contains the variables which are set before they |
127 | are used in a basic block. */ | |
ecddc799 | 128 | bitmap kills; |
4ee9c684 | 129 | }; |
130 | ||
8f6fa493 | 131 | /* It is advantageous to avoid things like life analysis for variables which |
132 | do not need PHI nodes. This enum describes whether or not a particular | |
133 | variable may need a PHI node. */ | |
134 | ||
135 | enum need_phi_state { | |
136 | /* This is the default. If we are still in this state after finding | |
137 | all the definition and use sites, then we will assume the variable | |
138 | needs PHI nodes. This is probably an overly conservative assumption. */ | |
139 | NEED_PHI_STATE_UNKNOWN, | |
140 | ||
141 | /* This state indicates that we have seen one or more sets of the | |
142 | variable in a single basic block and that the sets dominate all | |
143 | uses seen so far. If after finding all definition and use sites | |
144 | we are still in this state, then the variable does not need any | |
145 | PHI nodes. */ | |
146 | NEED_PHI_STATE_NO, | |
147 | ||
148 | /* This state indicates that we have either seen multiple definitions of | |
149 | the variable in multiple blocks, or that we encountered a use in a | |
150 | block that was not dominated by the block containing the set(s) of | |
151 | this variable. This variable is assumed to need PHI nodes. */ | |
152 | NEED_PHI_STATE_MAYBE | |
153 | }; | |
154 | ||
74105c0d | 155 | /* Information stored for both SSA names and decls. */ |
04009ada | 156 | struct common_info |
22d6c74e | 157 | { |
22d6c74e | 158 | /* This field indicates whether or not the variable may need PHI nodes. |
159 | See the enum's definition for more detailed information about the | |
160 | states. */ | |
161 | ENUM_BITFIELD (need_phi_state) need_phi_state : 2; | |
162 | ||
74105c0d | 163 | /* The current reaching definition replacing this var. */ |
22d6c74e | 164 | tree current_def; |
165 | ||
74105c0d | 166 | /* Definitions for this var. */ |
04009ada | 167 | struct def_blocks def_blocks; |
22d6c74e | 168 | }; |
169 | ||
74105c0d | 170 | /* Information stored for decls. */ |
04009ada | 171 | struct var_info |
74105c0d | 172 | { |
173 | /* The variable. */ | |
174 | tree var; | |
175 | ||
176 | /* Information stored for both SSA names and decls. */ | |
04009ada | 177 | common_info info; |
74105c0d | 178 | }; |
179 | ||
22d6c74e | 180 | |
3e871d4d | 181 | /* VAR_INFOS hashtable helpers. */ |
182 | ||
04009ada | 183 | struct var_info_hasher : free_ptr_hash <var_info> |
3e871d4d | 184 | { |
2933f7af | 185 | static inline hashval_t hash (const value_type &); |
186 | static inline bool equal (const value_type &, const compare_type &); | |
3e871d4d | 187 | }; |
188 | ||
189 | inline hashval_t | |
2933f7af | 190 | var_info_hasher::hash (const value_type &p) |
3e871d4d | 191 | { |
192 | return DECL_UID (p->var); | |
193 | } | |
194 | ||
195 | inline bool | |
2933f7af | 196 | var_info_hasher::equal (const value_type &p1, const compare_type &p2) |
3e871d4d | 197 | { |
198 | return p1->var == p2->var; | |
199 | } | |
200 | ||
201 | ||
22d6c74e | 202 | /* Each entry in VAR_INFOS contains an element of type STRUCT |
203 | VAR_INFO_D. */ | |
c1f445d2 | 204 | static hash_table<var_info_hasher> *var_infos; |
22d6c74e | 205 | |
206 | ||
88dbf20f | 207 | /* Information stored for SSA names. */ |
f3d9a16c | 208 | struct ssa_name_info |
209 | { | |
5eeafc2d | 210 | /* Age of this record (so that info_for_ssa_name table can be cleared |
211 | quickly); if AGE < CURRENT_INFO_FOR_SSA_NAME_AGE, then the fields | |
212 | are assumed to be null. */ | |
213 | unsigned age; | |
2920559d | 214 | |
5eeafc2d | 215 | /* Replacement mappings, allocated from update_ssa_obstack. */ |
216 | bitmap repl_set; | |
22d6c74e | 217 | |
74105c0d | 218 | /* Information stored for both SSA names and decls. */ |
04009ada | 219 | common_info info; |
f3d9a16c | 220 | }; |
4ee9c684 | 221 | |
04009ada | 222 | static vec<ssa_name_info *> info_for_ssa_name; |
2920559d | 223 | static unsigned current_info_for_ssa_name_age; |
224 | ||
5eeafc2d | 225 | static bitmap_obstack update_ssa_obstack; |
226 | ||
2920559d | 227 | /* The set of blocks affected by update_ssa. */ |
2920559d | 228 | static bitmap blocks_to_update; |
4ee9c684 | 229 | |
88dbf20f | 230 | /* The main entry point to the SSA renamer (rewrite_blocks) may be |
231 | called several times to do different, but related, tasks. | |
232 | Initially, we need it to rename the whole program into SSA form. | |
233 | At other times, we may need it to only rename into SSA newly | |
234 | exposed symbols. Finally, we can also call it to incrementally fix | |
235 | an already built SSA web. */ | |
236 | enum rewrite_mode { | |
237 | /* Convert the whole function into SSA form. */ | |
238 | REWRITE_ALL, | |
239 | ||
240 | /* Incrementally update the SSA web by replacing existing SSA | |
241 | names with new ones. See update_ssa for details. */ | |
242 | REWRITE_UPDATE | |
243 | }; | |
244 | ||
e70e8b13 | 245 | /* The set of symbols we ought to re-write into SSA form in update_ssa. */ |
246 | static bitmap symbols_to_rename_set; | |
f1f41a6c | 247 | static vec<tree> symbols_to_rename; |
e70e8b13 | 248 | |
249 | /* Mark SYM for renaming. */ | |
250 | ||
251 | static void | |
252 | mark_for_renaming (tree sym) | |
253 | { | |
254 | if (!symbols_to_rename_set) | |
255 | symbols_to_rename_set = BITMAP_ALLOC (NULL); | |
256 | if (bitmap_set_bit (symbols_to_rename_set, DECL_UID (sym))) | |
f1f41a6c | 257 | symbols_to_rename.safe_push (sym); |
e70e8b13 | 258 | } |
259 | ||
260 | /* Return true if SYM is marked for renaming. */ | |
261 | ||
262 | static bool | |
263 | marked_for_renaming (tree sym) | |
264 | { | |
ec11736b | 265 | if (!symbols_to_rename_set || sym == NULL_TREE) |
e70e8b13 | 266 | return false; |
267 | return bitmap_bit_p (symbols_to_rename_set, DECL_UID (sym)); | |
268 | } | |
269 | ||
270 | ||
75a70cf9 | 271 | /* Return true if STMT needs to be rewritten. When renaming a subset |
272 | of the variables, not all statements will be processed. This is | |
273 | decided in mark_def_sites. */ | |
274 | ||
275 | static inline bool | |
42acab1c | 276 | rewrite_uses_p (gimple *stmt) |
75a70cf9 | 277 | { |
278 | return gimple_visited_p (stmt); | |
279 | } | |
280 | ||
281 | ||
282 | /* Set the rewrite marker on STMT to the value given by REWRITE_P. */ | |
283 | ||
284 | static inline void | |
42acab1c | 285 | set_rewrite_uses (gimple *stmt, bool rewrite_p) |
75a70cf9 | 286 | { |
287 | gimple_set_visited (stmt, rewrite_p); | |
288 | } | |
289 | ||
290 | ||
291 | /* Return true if the DEFs created by statement STMT should be | |
292 | registered when marking new definition sites. This is slightly | |
293 | different than rewrite_uses_p: it's used by update_ssa to | |
294 | distinguish statements that need to have both uses and defs | |
295 | processed from those that only need to have their defs processed. | |
296 | Statements that define new SSA names only need to have their defs | |
297 | registered, but they don't need to have their uses renamed. */ | |
298 | ||
299 | static inline bool | |
42acab1c | 300 | register_defs_p (gimple *stmt) |
75a70cf9 | 301 | { |
302 | return gimple_plf (stmt, GF_PLF_1) != 0; | |
303 | } | |
304 | ||
305 | ||
306 | /* If REGISTER_DEFS_P is true, mark STMT to have its DEFs registered. */ | |
307 | ||
308 | static inline void | |
42acab1c | 309 | set_register_defs (gimple *stmt, bool register_defs_p) |
75a70cf9 | 310 | { |
311 | gimple_set_plf (stmt, GF_PLF_1, register_defs_p); | |
312 | } | |
313 | ||
314 | ||
f3d9a16c | 315 | /* Get the information associated with NAME. */ |
316 | ||
04009ada | 317 | static inline ssa_name_info * |
f3d9a16c | 318 | get_ssa_name_ann (tree name) |
319 | { | |
2920559d | 320 | unsigned ver = SSA_NAME_VERSION (name); |
f1f41a6c | 321 | unsigned len = info_for_ssa_name.length (); |
2920559d | 322 | struct ssa_name_info *info; |
323 | ||
83b709f2 | 324 | /* Re-allocate the vector at most once per update/into-SSA. */ |
2920559d | 325 | if (ver >= len) |
f1f41a6c | 326 | info_for_ssa_name.safe_grow_cleared (num_ssa_names); |
83b709f2 | 327 | |
328 | /* But allocate infos lazily. */ | |
f1f41a6c | 329 | info = info_for_ssa_name[ver]; |
83b709f2 | 330 | if (!info) |
2920559d | 331 | { |
83b709f2 | 332 | info = XCNEW (struct ssa_name_info); |
333 | info->age = current_info_for_ssa_name_age; | |
334 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
f1f41a6c | 335 | info_for_ssa_name[ver] = info; |
2920559d | 336 | } |
337 | ||
2920559d | 338 | if (info->age < current_info_for_ssa_name_age) |
339 | { | |
2920559d | 340 | info->age = current_info_for_ssa_name_age; |
74105c0d | 341 | info->repl_set = NULL; |
342 | info->info.need_phi_state = NEED_PHI_STATE_UNKNOWN; | |
343 | info->info.current_def = NULL_TREE; | |
344 | info->info.def_blocks.def_blocks = NULL; | |
345 | info->info.def_blocks.phi_blocks = NULL; | |
346 | info->info.def_blocks.livein_blocks = NULL; | |
2920559d | 347 | } |
f3d9a16c | 348 | |
2920559d | 349 | return info; |
f3d9a16c | 350 | } |
351 | ||
22d6c74e | 352 | /* Return and allocate the auxiliar information for DECL. */ |
353 | ||
04009ada | 354 | static inline var_info * |
22d6c74e | 355 | get_var_info (tree decl) |
356 | { | |
04009ada | 357 | var_info vi; |
358 | var_info **slot; | |
22d6c74e | 359 | vi.var = decl; |
c1f445d2 | 360 | slot = var_infos->find_slot_with_hash (&vi, DECL_UID (decl), INSERT); |
22d6c74e | 361 | if (*slot == NULL) |
362 | { | |
04009ada | 363 | var_info *v = XCNEW (var_info); |
22d6c74e | 364 | v->var = decl; |
3e871d4d | 365 | *slot = v; |
22d6c74e | 366 | return v; |
367 | } | |
3e871d4d | 368 | return *slot; |
22d6c74e | 369 | } |
370 | ||
4fb5e5ca | 371 | |
372 | /* Clears info for SSA names. */ | |
2920559d | 373 | |
374 | static void | |
375 | clear_ssa_name_info (void) | |
376 | { | |
377 | current_info_for_ssa_name_age++; | |
5eeafc2d | 378 | |
379 | /* If current_info_for_ssa_name_age wraps we use stale information. | |
380 | Asser that this does not happen. */ | |
381 | gcc_assert (current_info_for_ssa_name_age != 0); | |
2920559d | 382 | } |
e551bd1a | 383 | |
4fb5e5ca | 384 | |
74105c0d | 385 | /* Get access to the auxiliar information stored per SSA name or decl. */ |
f3d9a16c | 386 | |
04009ada | 387 | static inline common_info * |
74105c0d | 388 | get_common_info (tree var) |
f3d9a16c | 389 | { |
390 | if (TREE_CODE (var) == SSA_NAME) | |
74105c0d | 391 | return &get_ssa_name_ann (var)->info; |
f3d9a16c | 392 | else |
74105c0d | 393 | return &get_var_info (var)->info; |
f3d9a16c | 394 | } |
395 | ||
e551bd1a | 396 | |
f3d9a16c | 397 | /* Return the current definition for VAR. */ |
398 | ||
095dcfa3 | 399 | tree |
f3d9a16c | 400 | get_current_def (tree var) |
401 | { | |
74105c0d | 402 | return get_common_info (var)->current_def; |
f3d9a16c | 403 | } |
404 | ||
e551bd1a | 405 | |
f3d9a16c | 406 | /* Sets current definition of VAR to DEF. */ |
407 | ||
095dcfa3 | 408 | void |
f3d9a16c | 409 | set_current_def (tree var, tree def) |
410 | { | |
74105c0d | 411 | get_common_info (var)->current_def = def; |
f3d9a16c | 412 | } |
413 | ||
2920559d | 414 | /* Cleans up the REWRITE_THIS_STMT and REGISTER_DEFS_IN_THIS_STMT flags for |
415 | all statements in basic block BB. */ | |
416 | ||
417 | static void | |
418 | initialize_flags_in_bb (basic_block bb) | |
419 | { | |
42acab1c | 420 | gimple *stmt; |
75a70cf9 | 421 | gimple_stmt_iterator gsi; |
2920559d | 422 | |
75a70cf9 | 423 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 424 | { |
42acab1c | 425 | gimple *phi = gsi_stmt (gsi); |
75a70cf9 | 426 | set_rewrite_uses (phi, false); |
427 | set_register_defs (phi, false); | |
2920559d | 428 | } |
429 | ||
75a70cf9 | 430 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
2920559d | 431 | { |
75a70cf9 | 432 | stmt = gsi_stmt (gsi); |
433 | ||
2920559d | 434 | /* We are going to use the operand cache API, such as |
435 | SET_USE, SET_DEF, and FOR_EACH_IMM_USE_FAST. The operand | |
436 | cache for each statement should be up-to-date. */ | |
88536563 | 437 | gcc_checking_assert (!gimple_modified_p (stmt)); |
75a70cf9 | 438 | set_rewrite_uses (stmt, false); |
439 | set_register_defs (stmt, false); | |
2920559d | 440 | } |
441 | } | |
442 | ||
443 | /* Mark block BB as interesting for update_ssa. */ | |
444 | ||
445 | static void | |
446 | mark_block_for_update (basic_block bb) | |
447 | { | |
88536563 | 448 | gcc_checking_assert (blocks_to_update != NULL); |
39192870 | 449 | if (!bitmap_set_bit (blocks_to_update, bb->index)) |
2920559d | 450 | return; |
2920559d | 451 | initialize_flags_in_bb (bb); |
452 | } | |
453 | ||
e551bd1a | 454 | /* Return the set of blocks where variable VAR is defined and the blocks |
455 | where VAR is live on entry (livein). If no entry is found in | |
456 | DEF_BLOCKS, a new one is created and returned. */ | |
4ee9c684 | 457 | |
04009ada | 458 | static inline def_blocks * |
459 | get_def_blocks_for (common_info *info) | |
4ee9c684 | 460 | { |
04009ada | 461 | def_blocks *db_p = &info->def_blocks; |
22d6c74e | 462 | if (!db_p->def_blocks) |
4ee9c684 | 463 | { |
22d6c74e | 464 | db_p->def_blocks = BITMAP_ALLOC (&update_ssa_obstack); |
465 | db_p->phi_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
466 | db_p->livein_blocks = BITMAP_ALLOC (&update_ssa_obstack); | |
2cf24776 | 467 | } |
468 | ||
e551bd1a | 469 | return db_p; |
4ee9c684 | 470 | } |
471 | ||
6cf80e5b | 472 | |
f3d9a16c | 473 | /* Mark block BB as the definition site for variable VAR. PHI_P is true if |
88dbf20f | 474 | VAR is defined by a PHI node. */ |
4ee9c684 | 475 | |
476 | static void | |
88dbf20f | 477 | set_def_block (tree var, basic_block bb, bool phi_p) |
4ee9c684 | 478 | { |
04009ada | 479 | def_blocks *db_p; |
480 | common_info *info; | |
ce898113 | 481 | |
74105c0d | 482 | info = get_common_info (var); |
483 | db_p = get_def_blocks_for (info); | |
4ee9c684 | 484 | |
485 | /* Set the bit corresponding to the block where VAR is defined. */ | |
486 | bitmap_set_bit (db_p->def_blocks, bb->index); | |
f3d9a16c | 487 | if (phi_p) |
488 | bitmap_set_bit (db_p->phi_blocks, bb->index); | |
4ee9c684 | 489 | |
e551bd1a | 490 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 491 | |
492 | If we are in the UNKNOWN state, then this is the first definition | |
493 | of VAR. Additionally, we have not seen any uses of VAR yet, so | |
e551bd1a | 494 | we do not need a PHI node for this variable at this time (i.e., |
4ee9c684 | 495 | transition to NEED_PHI_STATE_NO). |
496 | ||
497 | If we are in any other state, then we either have multiple definitions | |
498 | of this variable occurring in different blocks or we saw a use of the | |
499 | variable which was not dominated by the block containing the | |
500 | definition(s). In this case we may need a PHI node, so enter | |
501 | state NEED_PHI_STATE_MAYBE. */ | |
74105c0d | 502 | if (info->need_phi_state == NEED_PHI_STATE_UNKNOWN) |
503 | info->need_phi_state = NEED_PHI_STATE_NO; | |
4ee9c684 | 504 | else |
74105c0d | 505 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 506 | } |
507 | ||
508 | ||
509 | /* Mark block BB as having VAR live at the entry to BB. */ | |
510 | ||
511 | static void | |
512 | set_livein_block (tree var, basic_block bb) | |
513 | { | |
04009ada | 514 | common_info *info; |
515 | def_blocks *db_p; | |
4ee9c684 | 516 | |
74105c0d | 517 | info = get_common_info (var); |
518 | db_p = get_def_blocks_for (info); | |
4ee9c684 | 519 | |
520 | /* Set the bit corresponding to the block where VAR is live in. */ | |
521 | bitmap_set_bit (db_p->livein_blocks, bb->index); | |
522 | ||
e551bd1a | 523 | /* Keep track of whether or not we may need to insert PHI nodes. |
4ee9c684 | 524 | |
525 | If we reach here in NEED_PHI_STATE_NO, see if this use is dominated | |
526 | by the single block containing the definition(s) of this variable. If | |
527 | it is, then we remain in NEED_PHI_STATE_NO, otherwise we transition to | |
528 | NEED_PHI_STATE_MAYBE. */ | |
74105c0d | 529 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
4ee9c684 | 530 | { |
531 | int def_block_index = bitmap_first_set_bit (db_p->def_blocks); | |
532 | ||
533 | if (def_block_index == -1 | |
534 | || ! dominated_by_p (CDI_DOMINATORS, bb, | |
f5a6b05f | 535 | BASIC_BLOCK_FOR_FN (cfun, def_block_index))) |
74105c0d | 536 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 537 | } |
538 | else | |
74105c0d | 539 | info->need_phi_state = NEED_PHI_STATE_MAYBE; |
4ee9c684 | 540 | } |
541 | ||
542 | ||
88dbf20f | 543 | /* Return true if NAME is in OLD_SSA_NAMES. */ |
4ee9c684 | 544 | |
88dbf20f | 545 | static inline bool |
546 | is_old_name (tree name) | |
547 | { | |
095dcfa3 | 548 | unsigned ver = SSA_NAME_VERSION (name); |
100be96d | 549 | if (!old_ssa_names) |
dd277d48 | 550 | return false; |
100be96d | 551 | return (ver < SBITMAP_SIZE (old_ssa_names) |
08b7917c | 552 | && bitmap_bit_p (old_ssa_names, ver)); |
88dbf20f | 553 | } |
554 | ||
555 | ||
556 | /* Return true if NAME is in NEW_SSA_NAMES. */ | |
ce898113 | 557 | |
88dbf20f | 558 | static inline bool |
559 | is_new_name (tree name) | |
560 | { | |
095dcfa3 | 561 | unsigned ver = SSA_NAME_VERSION (name); |
dd277d48 | 562 | if (!new_ssa_names) |
563 | return false; | |
156093aa | 564 | return (ver < SBITMAP_SIZE (new_ssa_names) |
08b7917c | 565 | && bitmap_bit_p (new_ssa_names, ver)); |
4ee9c684 | 566 | } |
567 | ||
e551bd1a | 568 | |
f4e36c33 | 569 | /* Return the names replaced by NEW_TREE (i.e., REPL_TBL[NEW_TREE].SET). */ |
88dbf20f | 570 | |
571 | static inline bitmap | |
f4e36c33 | 572 | names_replaced_by (tree new_tree) |
88dbf20f | 573 | { |
5eeafc2d | 574 | return get_ssa_name_ann (new_tree)->repl_set; |
88dbf20f | 575 | } |
576 | ||
577 | ||
f4e36c33 | 578 | /* Add OLD to REPL_TBL[NEW_TREE].SET. */ |
88dbf20f | 579 | |
580 | static inline void | |
f4e36c33 | 581 | add_to_repl_tbl (tree new_tree, tree old) |
88dbf20f | 582 | { |
5eeafc2d | 583 | bitmap *set = &get_ssa_name_ann (new_tree)->repl_set; |
584 | if (!*set) | |
585 | *set = BITMAP_ALLOC (&update_ssa_obstack); | |
586 | bitmap_set_bit (*set, SSA_NAME_VERSION (old)); | |
88dbf20f | 587 | } |
588 | ||
589 | ||
f4e36c33 | 590 | /* Add a new mapping NEW_TREE -> OLD REPL_TBL. Every entry N_i in REPL_TBL |
88dbf20f | 591 | represents the set of names O_1 ... O_j replaced by N_i. This is |
592 | used by update_ssa and its helpers to introduce new SSA names in an | |
593 | already formed SSA web. */ | |
594 | ||
595 | static void | |
f4e36c33 | 596 | add_new_name_mapping (tree new_tree, tree old) |
88dbf20f | 597 | { |
f4e36c33 | 598 | /* OLD and NEW_TREE must be different SSA names for the same symbol. */ |
88536563 | 599 | gcc_checking_assert (new_tree != old |
600 | && SSA_NAME_VAR (new_tree) == SSA_NAME_VAR (old)); | |
095dcfa3 | 601 | |
4fb5e5ca | 602 | /* We may need to grow NEW_SSA_NAMES and OLD_SSA_NAMES because our |
603 | caller may have created new names since the set was created. */ | |
156093aa | 604 | if (SBITMAP_SIZE (new_ssa_names) <= num_ssa_names - 1) |
4fb5e5ca | 605 | { |
606 | unsigned int new_sz = num_ssa_names + NAME_SETS_GROWTH_FACTOR; | |
607 | new_ssa_names = sbitmap_resize (new_ssa_names, new_sz, 0); | |
608 | old_ssa_names = sbitmap_resize (old_ssa_names, new_sz, 0); | |
88dbf20f | 609 | } |
610 | ||
88dbf20f | 611 | /* Update the REPL_TBL table. */ |
f4e36c33 | 612 | add_to_repl_tbl (new_tree, old); |
56004dc5 | 613 | |
88dbf20f | 614 | /* If OLD had already been registered as a new name, then all the |
f4e36c33 | 615 | names that OLD replaces should also be replaced by NEW_TREE. */ |
88dbf20f | 616 | if (is_new_name (old)) |
f4e36c33 | 617 | bitmap_ior_into (names_replaced_by (new_tree), names_replaced_by (old)); |
88dbf20f | 618 | |
f4e36c33 | 619 | /* Register NEW_TREE and OLD in NEW_SSA_NAMES and OLD_SSA_NAMES, |
88dbf20f | 620 | respectively. */ |
08b7917c | 621 | bitmap_set_bit (new_ssa_names, SSA_NAME_VERSION (new_tree)); |
622 | bitmap_set_bit (old_ssa_names, SSA_NAME_VERSION (old)); | |
56004dc5 | 623 | } |
4ee9c684 | 624 | |
4ee9c684 | 625 | |
e551bd1a | 626 | /* Call back for walk_dominator_tree used to collect definition sites |
627 | for every variable in the function. For every statement S in block | |
628 | BB: | |
4ee9c684 | 629 | |
b66731e8 | 630 | 1- Variables defined by S in the DEFS of S are marked in the bitmap |
6bf320fb | 631 | KILLS. |
4ee9c684 | 632 | |
e551bd1a | 633 | 2- If S uses a variable VAR and there is no preceding kill of VAR, |
5cdd0289 | 634 | then it is marked in the LIVEIN_BLOCKS bitmap associated with VAR. |
4ee9c684 | 635 | |
e551bd1a | 636 | This information is used to determine which variables are live |
637 | across block boundaries to reduce the number of PHI nodes | |
638 | we create. */ | |
4ee9c684 | 639 | |
e551bd1a | 640 | static void |
42acab1c | 641 | mark_def_sites (basic_block bb, gimple *stmt, bitmap kills) |
e551bd1a | 642 | { |
75a70cf9 | 643 | tree def; |
e551bd1a | 644 | use_operand_p use_p; |
e551bd1a | 645 | ssa_op_iter iter; |
646 | ||
75a70cf9 | 647 | /* Since this is the first time that we rewrite the program into SSA |
648 | form, force an operand scan on every statement. */ | |
75a70cf9 | 649 | update_stmt (stmt); |
e551bd1a | 650 | |
88536563 | 651 | gcc_checking_assert (blocks_to_update == NULL); |
75a70cf9 | 652 | set_register_defs (stmt, false); |
653 | set_rewrite_uses (stmt, false); | |
e551bd1a | 654 | |
9845d120 | 655 | if (is_gimple_debug (stmt)) |
841424cc | 656 | { |
657 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
658 | { | |
659 | tree sym = USE_FROM_PTR (use_p); | |
88536563 | 660 | gcc_checking_assert (DECL_P (sym)); |
841424cc | 661 | set_rewrite_uses (stmt, true); |
662 | } | |
663 | if (rewrite_uses_p (stmt)) | |
08b7917c | 664 | bitmap_set_bit (interesting_blocks, bb->index); |
841424cc | 665 | return; |
666 | } | |
9845d120 | 667 | |
e551bd1a | 668 | /* If a variable is used before being set, then the variable is live |
669 | across a block boundary, so mark it live-on-entry to BB. */ | |
5aabc5f2 | 670 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
e551bd1a | 671 | { |
88dbf20f | 672 | tree sym = USE_FROM_PTR (use_p); |
9ae1b28a | 673 | if (TREE_CODE (sym) == SSA_NAME) |
674 | continue; | |
88536563 | 675 | gcc_checking_assert (DECL_P (sym)); |
a55dc2cd | 676 | if (!bitmap_bit_p (kills, DECL_UID (sym))) |
88dbf20f | 677 | set_livein_block (sym, bb); |
75a70cf9 | 678 | set_rewrite_uses (stmt, true); |
e551bd1a | 679 | } |
48e1416a | 680 | |
4fb5e5ca | 681 | /* Now process the defs. Mark BB as the definition block and add |
682 | each def to the set of killed symbols. */ | |
5aabc5f2 | 683 | FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS) |
e551bd1a | 684 | { |
9ae1b28a | 685 | if (TREE_CODE (def) == SSA_NAME) |
686 | continue; | |
88536563 | 687 | gcc_checking_assert (DECL_P (def)); |
88dbf20f | 688 | set_def_block (def, bb, false); |
a55dc2cd | 689 | bitmap_set_bit (kills, DECL_UID (def)); |
75a70cf9 | 690 | set_register_defs (stmt, true); |
e551bd1a | 691 | } |
88dbf20f | 692 | |
693 | /* If we found the statement interesting then also mark the block BB | |
694 | as interesting. */ | |
75a70cf9 | 695 | if (rewrite_uses_p (stmt) || register_defs_p (stmt)) |
08b7917c | 696 | bitmap_set_bit (interesting_blocks, bb->index); |
e551bd1a | 697 | } |
698 | ||
f50cf978 | 699 | /* Structure used by prune_unused_phi_nodes to record bounds of the intervals |
700 | in the dfs numbering of the dominance tree. */ | |
701 | ||
702 | struct dom_dfsnum | |
703 | { | |
704 | /* Basic block whose index this entry corresponds to. */ | |
705 | unsigned bb_index; | |
706 | ||
707 | /* The dfs number of this node. */ | |
708 | unsigned dfs_num; | |
709 | }; | |
710 | ||
711 | /* Compares two entries of type struct dom_dfsnum by dfs_num field. Callback | |
712 | for qsort. */ | |
713 | ||
714 | static int | |
715 | cmp_dfsnum (const void *a, const void *b) | |
716 | { | |
45ba1503 | 717 | const struct dom_dfsnum *const da = (const struct dom_dfsnum *) a; |
718 | const struct dom_dfsnum *const db = (const struct dom_dfsnum *) b; | |
f50cf978 | 719 | |
720 | return (int) da->dfs_num - (int) db->dfs_num; | |
721 | } | |
722 | ||
723 | /* Among the intervals starting at the N points specified in DEFS, find | |
724 | the one that contains S, and return its bb_index. */ | |
725 | ||
726 | static unsigned | |
727 | find_dfsnum_interval (struct dom_dfsnum *defs, unsigned n, unsigned s) | |
728 | { | |
729 | unsigned f = 0, t = n, m; | |
730 | ||
731 | while (t > f + 1) | |
732 | { | |
733 | m = (f + t) / 2; | |
734 | if (defs[m].dfs_num <= s) | |
735 | f = m; | |
736 | else | |
737 | t = m; | |
738 | } | |
739 | ||
740 | return defs[f].bb_index; | |
741 | } | |
742 | ||
743 | /* Clean bits from PHIS for phi nodes whose value cannot be used in USES. | |
744 | KILLS is a bitmap of blocks where the value is defined before any use. */ | |
745 | ||
746 | static void | |
747 | prune_unused_phi_nodes (bitmap phis, bitmap kills, bitmap uses) | |
748 | { | |
f50cf978 | 749 | bitmap_iterator bi; |
750 | unsigned i, b, p, u, top; | |
751 | bitmap live_phis; | |
752 | basic_block def_bb, use_bb; | |
753 | edge e; | |
754 | edge_iterator ei; | |
755 | bitmap to_remove; | |
756 | struct dom_dfsnum *defs; | |
757 | unsigned n_defs, adef; | |
758 | ||
759 | if (bitmap_empty_p (uses)) | |
760 | { | |
761 | bitmap_clear (phis); | |
762 | return; | |
763 | } | |
764 | ||
765 | /* The phi must dominate a use, or an argument of a live phi. Also, we | |
766 | do not create any phi nodes in def blocks, unless they are also livein. */ | |
767 | to_remove = BITMAP_ALLOC (NULL); | |
768 | bitmap_and_compl (to_remove, kills, uses); | |
769 | bitmap_and_compl_into (phis, to_remove); | |
770 | if (bitmap_empty_p (phis)) | |
771 | { | |
772 | BITMAP_FREE (to_remove); | |
773 | return; | |
774 | } | |
775 | ||
776 | /* We want to remove the unnecessary phi nodes, but we do not want to compute | |
777 | liveness information, as that may be linear in the size of CFG, and if | |
778 | there are lot of different variables to rewrite, this may lead to quadratic | |
779 | behavior. | |
780 | ||
781 | Instead, we basically emulate standard dce. We put all uses to worklist, | |
782 | then for each of them find the nearest def that dominates them. If this | |
783 | def is a phi node, we mark it live, and if it was not live before, we | |
784 | add the predecessors of its basic block to the worklist. | |
48e1416a | 785 | |
f50cf978 | 786 | To quickly locate the nearest def that dominates use, we use dfs numbering |
787 | of the dominance tree (that is already available in order to speed up | |
788 | queries). For each def, we have the interval given by the dfs number on | |
789 | entry to and on exit from the corresponding subtree in the dominance tree. | |
790 | The nearest dominator for a given use is the smallest of these intervals | |
791 | that contains entry and exit dfs numbers for the basic block with the use. | |
792 | If we store the bounds for all the uses to an array and sort it, we can | |
793 | locate the nearest dominating def in logarithmic time by binary search.*/ | |
794 | bitmap_ior (to_remove, kills, phis); | |
795 | n_defs = bitmap_count_bits (to_remove); | |
796 | defs = XNEWVEC (struct dom_dfsnum, 2 * n_defs + 1); | |
797 | defs[0].bb_index = 1; | |
798 | defs[0].dfs_num = 0; | |
799 | adef = 1; | |
800 | EXECUTE_IF_SET_IN_BITMAP (to_remove, 0, i, bi) | |
801 | { | |
f5a6b05f | 802 | def_bb = BASIC_BLOCK_FOR_FN (cfun, i); |
f50cf978 | 803 | defs[adef].bb_index = i; |
804 | defs[adef].dfs_num = bb_dom_dfs_in (CDI_DOMINATORS, def_bb); | |
805 | defs[adef + 1].bb_index = i; | |
806 | defs[adef + 1].dfs_num = bb_dom_dfs_out (CDI_DOMINATORS, def_bb); | |
807 | adef += 2; | |
808 | } | |
809 | BITMAP_FREE (to_remove); | |
810 | gcc_assert (adef == 2 * n_defs + 1); | |
811 | qsort (defs, adef, sizeof (struct dom_dfsnum), cmp_dfsnum); | |
812 | gcc_assert (defs[0].bb_index == 1); | |
813 | ||
814 | /* Now each DEFS entry contains the number of the basic block to that the | |
815 | dfs number corresponds. Change them to the number of basic block that | |
816 | corresponds to the interval following the dfs number. Also, for the | |
817 | dfs_out numbers, increase the dfs number by one (so that it corresponds | |
818 | to the start of the following interval, not to the end of the current | |
819 | one). We use WORKLIST as a stack. */ | |
c2078b80 | 820 | auto_vec<int> worklist (n_defs + 1); |
f1f41a6c | 821 | worklist.quick_push (1); |
f50cf978 | 822 | top = 1; |
823 | n_defs = 1; | |
824 | for (i = 1; i < adef; i++) | |
825 | { | |
826 | b = defs[i].bb_index; | |
827 | if (b == top) | |
828 | { | |
829 | /* This is a closing element. Interval corresponding to the top | |
830 | of the stack after removing it follows. */ | |
f1f41a6c | 831 | worklist.pop (); |
832 | top = worklist[worklist.length () - 1]; | |
f50cf978 | 833 | defs[n_defs].bb_index = top; |
834 | defs[n_defs].dfs_num = defs[i].dfs_num + 1; | |
835 | } | |
836 | else | |
837 | { | |
838 | /* Opening element. Nothing to do, just push it to the stack and move | |
839 | it to the correct position. */ | |
840 | defs[n_defs].bb_index = defs[i].bb_index; | |
841 | defs[n_defs].dfs_num = defs[i].dfs_num; | |
f1f41a6c | 842 | worklist.quick_push (b); |
f50cf978 | 843 | top = b; |
844 | } | |
845 | ||
846 | /* If this interval starts at the same point as the previous one, cancel | |
847 | the previous one. */ | |
848 | if (defs[n_defs].dfs_num == defs[n_defs - 1].dfs_num) | |
849 | defs[n_defs - 1].bb_index = defs[n_defs].bb_index; | |
850 | else | |
851 | n_defs++; | |
852 | } | |
f1f41a6c | 853 | worklist.pop (); |
854 | gcc_assert (worklist.is_empty ()); | |
f50cf978 | 855 | |
856 | /* Now process the uses. */ | |
857 | live_phis = BITMAP_ALLOC (NULL); | |
858 | EXECUTE_IF_SET_IN_BITMAP (uses, 0, i, bi) | |
859 | { | |
f1f41a6c | 860 | worklist.safe_push (i); |
f50cf978 | 861 | } |
862 | ||
f1f41a6c | 863 | while (!worklist.is_empty ()) |
f50cf978 | 864 | { |
f1f41a6c | 865 | b = worklist.pop (); |
f50cf978 | 866 | if (b == ENTRY_BLOCK) |
867 | continue; | |
868 | ||
869 | /* If there is a phi node in USE_BB, it is made live. Otherwise, | |
870 | find the def that dominates the immediate dominator of USE_BB | |
871 | (the kill in USE_BB does not dominate the use). */ | |
872 | if (bitmap_bit_p (phis, b)) | |
873 | p = b; | |
874 | else | |
875 | { | |
f5a6b05f | 876 | use_bb = get_immediate_dominator (CDI_DOMINATORS, |
877 | BASIC_BLOCK_FOR_FN (cfun, b)); | |
f50cf978 | 878 | p = find_dfsnum_interval (defs, n_defs, |
879 | bb_dom_dfs_in (CDI_DOMINATORS, use_bb)); | |
880 | if (!bitmap_bit_p (phis, p)) | |
881 | continue; | |
882 | } | |
883 | ||
884 | /* If the phi node is already live, there is nothing to do. */ | |
6ef9bbe0 | 885 | if (!bitmap_set_bit (live_phis, p)) |
f50cf978 | 886 | continue; |
887 | ||
6ef9bbe0 | 888 | /* Add the new uses to the worklist. */ |
f5a6b05f | 889 | def_bb = BASIC_BLOCK_FOR_FN (cfun, p); |
f50cf978 | 890 | FOR_EACH_EDGE (e, ei, def_bb->preds) |
891 | { | |
892 | u = e->src->index; | |
893 | if (bitmap_bit_p (uses, u)) | |
894 | continue; | |
895 | ||
94858f65 | 896 | /* In case there is a kill directly in the use block, do not record |
897 | the use (this is also necessary for correctness, as we assume that | |
898 | uses dominated by a def directly in their block have been filtered | |
899 | out before). */ | |
900 | if (bitmap_bit_p (kills, u)) | |
901 | continue; | |
902 | ||
f50cf978 | 903 | bitmap_set_bit (uses, u); |
f1f41a6c | 904 | worklist.safe_push (u); |
f50cf978 | 905 | } |
906 | } | |
907 | ||
f50cf978 | 908 | bitmap_copy (phis, live_phis); |
909 | BITMAP_FREE (live_phis); | |
910 | free (defs); | |
911 | } | |
e551bd1a | 912 | |
e551bd1a | 913 | /* Return the set of blocks where variable VAR is defined and the blocks |
914 | where VAR is live on entry (livein). Return NULL, if no entry is | |
915 | found in DEF_BLOCKS. */ | |
916 | ||
04009ada | 917 | static inline def_blocks * |
e551bd1a | 918 | find_def_blocks_for (tree var) |
919 | { | |
04009ada | 920 | def_blocks *p = &get_common_info (var)->def_blocks; |
22d6c74e | 921 | if (!p->def_blocks) |
922 | return NULL; | |
923 | return p; | |
e551bd1a | 924 | } |
925 | ||
926 | ||
70630fcd | 927 | /* Marks phi node PHI in basic block BB for rewrite. */ |
928 | ||
929 | static void | |
1a91d914 | 930 | mark_phi_for_rewrite (basic_block bb, gphi *phi) |
70630fcd | 931 | { |
1a91d914 | 932 | vec<gphi *> phis; |
2670407e | 933 | unsigned n, idx = bb->index; |
70630fcd | 934 | |
75a70cf9 | 935 | if (rewrite_uses_p (phi)) |
70630fcd | 936 | return; |
4fb5e5ca | 937 | |
75a70cf9 | 938 | set_rewrite_uses (phi, true); |
70630fcd | 939 | |
940 | if (!blocks_with_phis_to_rewrite) | |
941 | return; | |
942 | ||
943 | bitmap_set_bit (blocks_with_phis_to_rewrite, idx); | |
2670407e | 944 | |
fe672ac0 | 945 | n = (unsigned) last_basic_block_for_fn (cfun) + 1; |
f1f41a6c | 946 | if (phis_to_rewrite.length () < n) |
947 | phis_to_rewrite.safe_grow_cleared (n); | |
70630fcd | 948 | |
f1f41a6c | 949 | phis = phis_to_rewrite[idx]; |
950 | phis.reserve (10); | |
70630fcd | 951 | |
f1f41a6c | 952 | phis.safe_push (phi); |
953 | phis_to_rewrite[idx] = phis; | |
70630fcd | 954 | } |
955 | ||
e551bd1a | 956 | /* Insert PHI nodes for variable VAR using the iterated dominance |
88dbf20f | 957 | frontier given in PHI_INSERTION_POINTS. If UPDATE_P is true, this |
4fb5e5ca | 958 | function assumes that the caller is incrementally updating the |
959 | existing SSA form, in which case VAR may be an SSA name instead of | |
960 | a symbol. | |
88dbf20f | 961 | |
962 | PHI_INSERTION_POINTS is updated to reflect nodes that already had a | |
963 | PHI node for VAR. On exit, only the nodes that received a PHI node | |
964 | for VAR will be present in PHI_INSERTION_POINTS. */ | |
e551bd1a | 965 | |
966 | static void | |
88dbf20f | 967 | insert_phi_nodes_for (tree var, bitmap phi_insertion_points, bool update_p) |
e551bd1a | 968 | { |
969 | unsigned bb_index; | |
970 | edge e; | |
1a91d914 | 971 | gphi *phi; |
e551bd1a | 972 | basic_block bb; |
973 | bitmap_iterator bi; | |
04009ada | 974 | def_blocks *def_map = find_def_blocks_for (var); |
e551bd1a | 975 | |
976 | /* Remove the blocks where we already have PHI nodes for VAR. */ | |
977 | bitmap_and_compl_into (phi_insertion_points, def_map->phi_blocks); | |
978 | ||
f50cf978 | 979 | /* Remove obviously useless phi nodes. */ |
980 | prune_unused_phi_nodes (phi_insertion_points, def_map->def_blocks, | |
981 | def_map->livein_blocks); | |
e551bd1a | 982 | |
983 | /* And insert the PHI nodes. */ | |
f50cf978 | 984 | EXECUTE_IF_SET_IN_BITMAP (phi_insertion_points, 0, bb_index, bi) |
e551bd1a | 985 | { |
f5a6b05f | 986 | bb = BASIC_BLOCK_FOR_FN (cfun, bb_index); |
2920559d | 987 | if (update_p) |
988 | mark_block_for_update (bb); | |
e551bd1a | 989 | |
487c79c3 | 990 | if (dump_file && (dump_flags & TDF_DETAILS)) |
991 | { | |
992 | fprintf (dump_file, "creating PHI node in block #%d for ", bb_index); | |
993 | print_generic_expr (dump_file, var, TDF_SLIM); | |
994 | fprintf (dump_file, "\n"); | |
995 | } | |
75a70cf9 | 996 | phi = NULL; |
4fb5e5ca | 997 | |
998 | if (TREE_CODE (var) == SSA_NAME) | |
e551bd1a | 999 | { |
095dcfa3 | 1000 | /* If we are rewriting SSA names, create the LHS of the PHI |
1001 | node by duplicating VAR. This is useful in the case of | |
1002 | pointers, to also duplicate pointer attributes (alias | |
1003 | information, in particular). */ | |
e551bd1a | 1004 | edge_iterator ei; |
095dcfa3 | 1005 | tree new_lhs; |
88dbf20f | 1006 | |
88536563 | 1007 | gcc_checking_assert (update_p); |
9c06f260 | 1008 | new_lhs = duplicate_ssa_name (var, NULL); |
1009 | phi = create_phi_node (new_lhs, bb); | |
095dcfa3 | 1010 | add_new_name_mapping (new_lhs, var); |
88dbf20f | 1011 | |
1012 | /* Add VAR to every argument slot of PHI. We need VAR in | |
1013 | every argument so that rewrite_update_phi_arguments knows | |
1014 | which name is this PHI node replacing. If VAR is a | |
1015 | symbol marked for renaming, this is not necessary, the | |
1016 | renamer will use the symbol on the LHS to get its | |
1017 | reaching definition. */ | |
e551bd1a | 1018 | FOR_EACH_EDGE (e, ei, bb->preds) |
60d535d2 | 1019 | add_phi_arg (phi, var, e, UNKNOWN_LOCATION); |
e551bd1a | 1020 | } |
095dcfa3 | 1021 | else |
1022 | { | |
9845d120 | 1023 | tree tracked_var; |
cd610ee6 | 1024 | |
88536563 | 1025 | gcc_checking_assert (DECL_P (var)); |
25ae9ba2 | 1026 | phi = create_phi_node (var, bb); |
cd610ee6 | 1027 | |
1028 | tracked_var = target_for_debug_bind (var); | |
1029 | if (tracked_var) | |
9845d120 | 1030 | { |
42acab1c | 1031 | gimple *note = gimple_build_debug_bind (tracked_var, |
1032 | PHI_RESULT (phi), | |
9845d120 | 1033 | phi); |
1034 | gimple_stmt_iterator si = gsi_after_labels (bb); | |
1035 | gsi_insert_before (&si, note, GSI_SAME_STMT); | |
1036 | } | |
095dcfa3 | 1037 | } |
88dbf20f | 1038 | |
1039 | /* Mark this PHI node as interesting for update_ssa. */ | |
75a70cf9 | 1040 | set_register_defs (phi, true); |
70630fcd | 1041 | mark_phi_for_rewrite (bb, phi); |
e551bd1a | 1042 | } |
1043 | } | |
1044 | ||
22d6c74e | 1045 | /* Sort var_infos after DECL_UID of their var. */ |
c86a4051 | 1046 | |
1047 | static int | |
22d6c74e | 1048 | insert_phi_nodes_compare_var_infos (const void *a, const void *b) |
c86a4051 | 1049 | { |
04009ada | 1050 | const var_info *defa = *(var_info * const *)a; |
1051 | const var_info *defb = *(var_info * const *)b; | |
c86a4051 | 1052 | if (DECL_UID (defa->var) < DECL_UID (defb->var)) |
1053 | return -1; | |
1054 | else | |
1055 | return 1; | |
1056 | } | |
e551bd1a | 1057 | |
e551bd1a | 1058 | /* Insert PHI nodes at the dominance frontier of blocks with variable |
1059 | definitions. DFS contains the dominance frontier information for | |
4fb5e5ca | 1060 | the flowgraph. */ |
e551bd1a | 1061 | |
1062 | static void | |
8a2980be | 1063 | insert_phi_nodes (bitmap_head *dfs) |
e551bd1a | 1064 | { |
c1f445d2 | 1065 | hash_table<var_info_hasher>::iterator hi; |
c86a4051 | 1066 | unsigned i; |
04009ada | 1067 | var_info *info; |
e551bd1a | 1068 | |
1069 | timevar_push (TV_TREE_INSERT_PHI_NODES); | |
48e1416a | 1070 | |
a718e363 | 1071 | /* When the gimplifier introduces SSA names it cannot easily avoid |
1072 | situations where abnormal edges added by CFG construction break | |
1073 | the use-def dominance requirement. For this case rewrite SSA | |
1074 | names with broken use-def dominance out-of-SSA and register them | |
1075 | for PHI insertion. We only need to do this if abnormal edges | |
1076 | can appear in the function. */ | |
1077 | tree name; | |
1078 | if (cfun->calls_setjmp | |
1079 | || cfun->has_nonlocal_label) | |
1080 | FOR_EACH_SSA_NAME (i, name, cfun) | |
1081 | { | |
1082 | gimple *def_stmt = SSA_NAME_DEF_STMT (name); | |
1083 | if (SSA_NAME_IS_DEFAULT_DEF (name)) | |
1084 | continue; | |
1085 | ||
1086 | basic_block def_bb = gimple_bb (def_stmt); | |
1087 | imm_use_iterator it; | |
1088 | gimple *use_stmt; | |
1089 | bool need_phis = false; | |
1090 | FOR_EACH_IMM_USE_STMT (use_stmt, it, name) | |
1091 | { | |
1092 | basic_block use_bb = gimple_bb (use_stmt); | |
1093 | if (use_bb != def_bb | |
1094 | && ! dominated_by_p (CDI_DOMINATORS, use_bb, def_bb)) | |
1095 | need_phis = true; | |
1096 | } | |
1097 | if (need_phis) | |
1098 | { | |
1099 | tree var = create_tmp_reg (TREE_TYPE (name)); | |
1100 | use_operand_p use_p; | |
1101 | FOR_EACH_IMM_USE_STMT (use_stmt, it, name) | |
1102 | { | |
1103 | basic_block use_bb = gimple_bb (use_stmt); | |
1104 | FOR_EACH_IMM_USE_ON_STMT (use_p, it) | |
1105 | SET_USE (use_p, var); | |
1106 | update_stmt (use_stmt); | |
1107 | set_livein_block (var, use_bb); | |
1108 | set_rewrite_uses (use_stmt, true); | |
1109 | bitmap_set_bit (interesting_blocks, use_bb->index); | |
1110 | } | |
1111 | def_operand_p def_p; | |
1112 | ssa_op_iter dit; | |
1113 | FOR_EACH_SSA_DEF_OPERAND (def_p, def_stmt, dit, SSA_OP_DEF) | |
1114 | if (DEF_FROM_PTR (def_p) == name) | |
1115 | SET_DEF (def_p, var); | |
1116 | update_stmt (def_stmt); | |
1117 | set_def_block (var, def_bb, false); | |
1118 | set_register_defs (def_stmt, true); | |
1119 | bitmap_set_bit (interesting_blocks, def_bb->index); | |
1120 | release_ssa_name (name); | |
1121 | } | |
1122 | } | |
1123 | ||
04009ada | 1124 | auto_vec<var_info *> vars (var_infos->elements ()); |
c1f445d2 | 1125 | FOR_EACH_HASH_TABLE_ELEMENT (*var_infos, info, var_info_p, hi) |
74105c0d | 1126 | if (info->info.need_phi_state != NEED_PHI_STATE_NO) |
f1f41a6c | 1127 | vars.quick_push (info); |
c86a4051 | 1128 | |
409a375f | 1129 | /* Do two stages to avoid code generation differences for UID |
1130 | differences but no UID ordering differences. */ | |
f1f41a6c | 1131 | vars.qsort (insert_phi_nodes_compare_var_infos); |
409a375f | 1132 | |
f1f41a6c | 1133 | FOR_EACH_VEC_ELT (vars, i, info) |
f3d9a16c | 1134 | { |
74105c0d | 1135 | bitmap idf = compute_idf (info->info.def_blocks.def_blocks, dfs); |
22d6c74e | 1136 | insert_phi_nodes_for (info->var, idf, false); |
409a375f | 1137 | BITMAP_FREE (idf); |
1138 | } | |
1139 | ||
4ee9c684 | 1140 | timevar_pop (TV_TREE_INSERT_PHI_NODES); |
1141 | } | |
1142 | ||
1143 | ||
4fb5e5ca | 1144 | /* Push SYM's current reaching definition into BLOCK_DEFS_STACK and |
1145 | register DEF (an SSA_NAME) to be a new definition for SYM. */ | |
e551bd1a | 1146 | |
de6ed584 | 1147 | static void |
4fb5e5ca | 1148 | register_new_def (tree def, tree sym) |
e551bd1a | 1149 | { |
04009ada | 1150 | common_info *info = get_common_info (sym); |
e551bd1a | 1151 | tree currdef; |
48e1416a | 1152 | |
e551bd1a | 1153 | /* If this variable is set in a single basic block and all uses are |
1154 | dominated by the set(s) in that single basic block, then there is | |
1155 | no reason to record anything for this variable in the block local | |
1156 | definition stacks. Doing so just wastes time and memory. | |
1157 | ||
1158 | This is the same test to prune the set of variables which may | |
1159 | need PHI nodes. So we just use that information since it's already | |
1160 | computed and available for us to use. */ | |
74105c0d | 1161 | if (info->need_phi_state == NEED_PHI_STATE_NO) |
e551bd1a | 1162 | { |
74105c0d | 1163 | info->current_def = def; |
e551bd1a | 1164 | return; |
1165 | } | |
1166 | ||
74105c0d | 1167 | currdef = info->current_def; |
e551bd1a | 1168 | |
4fb5e5ca | 1169 | /* If SYM is not a GIMPLE register, then CURRDEF may be a name whose |
1170 | SSA_NAME_VAR is not necessarily SYM. In this case, also push SYM | |
1171 | in the stack so that we know which symbol is being defined by | |
1172 | this SSA name when we unwind the stack. */ | |
1173 | if (currdef && !is_gimple_reg (sym)) | |
f1f41a6c | 1174 | block_defs_stack.safe_push (sym); |
e551bd1a | 1175 | |
4fb5e5ca | 1176 | /* Push the current reaching definition into BLOCK_DEFS_STACK. This |
1177 | stack is later used by the dominator tree callbacks to restore | |
1178 | the reaching definitions for all the variables defined in the | |
1179 | block after a recursive visit to all its immediately dominated | |
1180 | blocks. If there is no current reaching definition, then just | |
1181 | record the underlying _DECL node. */ | |
f1f41a6c | 1182 | block_defs_stack.safe_push (currdef ? currdef : sym); |
4fb5e5ca | 1183 | |
1184 | /* Set the current reaching definition for SYM to be DEF. */ | |
74105c0d | 1185 | info->current_def = def; |
e551bd1a | 1186 | } |
1187 | ||
1188 | ||
4ee9c684 | 1189 | /* Perform a depth-first traversal of the dominator tree looking for |
1190 | variables to rename. BB is the block where to start searching. | |
1191 | Renaming is a five step process: | |
1192 | ||
1193 | 1- Every definition made by PHI nodes at the start of the blocks is | |
1194 | registered as the current definition for the corresponding variable. | |
1195 | ||
1196 | 2- Every statement in BB is rewritten. USE and VUSE operands are | |
1197 | rewritten with their corresponding reaching definition. DEF and | |
1198 | VDEF targets are registered as new definitions. | |
48e1416a | 1199 | |
4ee9c684 | 1200 | 3- All the PHI nodes in successor blocks of BB are visited. The |
1201 | argument corresponding to BB is replaced with its current reaching | |
1202 | definition. | |
1203 | ||
1204 | 4- Recursively rewrite every dominator child block of BB. | |
1205 | ||
1206 | 5- Restore (in reverse order) the current reaching definition for every | |
1207 | new definition introduced in this block. This is done so that when | |
1208 | we return from the recursive call, all the current reaching | |
1209 | definitions are restored to the names that were valid in the | |
1210 | dominator parent of BB. */ | |
1211 | ||
e551bd1a | 1212 | /* Return the current definition for variable VAR. If none is found, |
4fb5e5ca | 1213 | create a new SSA name to act as the zeroth definition for VAR. */ |
f3d9a16c | 1214 | |
e551bd1a | 1215 | static tree |
1216 | get_reaching_def (tree var) | |
1217 | { | |
04009ada | 1218 | common_info *info = get_common_info (var); |
4fb5e5ca | 1219 | tree currdef; |
48e1416a | 1220 | |
e551bd1a | 1221 | /* Lookup the current reaching definition for VAR. */ |
74105c0d | 1222 | currdef = info->current_def; |
f3d9a16c | 1223 | |
e551bd1a | 1224 | /* If there is no reaching definition for VAR, create and register a |
1225 | default definition for it (if needed). */ | |
4fb5e5ca | 1226 | if (currdef == NULL_TREE) |
e551bd1a | 1227 | { |
4fb5e5ca | 1228 | tree sym = DECL_P (var) ? var : SSA_NAME_VAR (var); |
74936b22 | 1229 | if (! sym) |
1230 | sym = create_tmp_reg (TREE_TYPE (var)); | |
c6dfe037 | 1231 | currdef = get_or_create_ssa_default_def (cfun, sym); |
e551bd1a | 1232 | } |
1233 | ||
1234 | /* Return the current reaching definition for VAR, or the default | |
1235 | definition, if we had to create one. */ | |
4fb5e5ca | 1236 | return currdef; |
e551bd1a | 1237 | } |
1238 | ||
1239 | ||
841424cc | 1240 | /* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */ |
1241 | ||
1242 | static void | |
42acab1c | 1243 | rewrite_debug_stmt_uses (gimple *stmt) |
841424cc | 1244 | { |
1245 | use_operand_p use_p; | |
1246 | ssa_op_iter iter; | |
1247 | bool update = false; | |
1248 | ||
1249 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
1250 | { | |
4ae5778c | 1251 | tree var = USE_FROM_PTR (use_p), def; |
04009ada | 1252 | common_info *info = get_common_info (var); |
88536563 | 1253 | gcc_checking_assert (DECL_P (var)); |
74105c0d | 1254 | def = info->current_def; |
4ae5778c | 1255 | if (!def) |
841424cc | 1256 | { |
34154e27 | 1257 | if (TREE_CODE (var) == PARM_DECL |
1258 | && single_succ_p (ENTRY_BLOCK_PTR_FOR_FN (cfun))) | |
841424cc | 1259 | { |
1260 | gimple_stmt_iterator gsi | |
34154e27 | 1261 | = |
1262 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
841424cc | 1263 | int lim; |
1264 | /* Search a few source bind stmts at the start of first bb to | |
1265 | see if a DEBUG_EXPR_DECL can't be reused. */ | |
1266 | for (lim = 32; | |
1267 | !gsi_end_p (gsi) && lim > 0; | |
1268 | gsi_next (&gsi), lim--) | |
1269 | { | |
42acab1c | 1270 | gimple *gstmt = gsi_stmt (gsi); |
841424cc | 1271 | if (!gimple_debug_source_bind_p (gstmt)) |
1272 | break; | |
1273 | if (gimple_debug_source_bind_get_value (gstmt) == var) | |
1274 | { | |
1275 | def = gimple_debug_source_bind_get_var (gstmt); | |
1276 | if (TREE_CODE (def) == DEBUG_EXPR_DECL) | |
1277 | break; | |
1278 | else | |
1279 | def = NULL_TREE; | |
1280 | } | |
1281 | } | |
1282 | /* If not, add a new source bind stmt. */ | |
1283 | if (def == NULL_TREE) | |
1284 | { | |
42acab1c | 1285 | gimple *def_temp; |
841424cc | 1286 | def = make_node (DEBUG_EXPR_DECL); |
1287 | def_temp = gimple_build_debug_source_bind (def, var, NULL); | |
1288 | DECL_ARTIFICIAL (def) = 1; | |
1289 | TREE_TYPE (def) = TREE_TYPE (var); | |
adc78298 | 1290 | SET_DECL_MODE (def, DECL_MODE (var)); |
34154e27 | 1291 | gsi = |
1292 | gsi_after_labels (single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun))); | |
841424cc | 1293 | gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT); |
1294 | } | |
1295 | update = true; | |
1296 | } | |
1297 | } | |
1298 | else | |
824651eb | 1299 | { |
74105c0d | 1300 | /* Check if info->current_def can be trusted. */ |
4ae5778c | 1301 | basic_block bb = gimple_bb (stmt); |
1302 | basic_block def_bb | |
1303 | = SSA_NAME_IS_DEFAULT_DEF (def) | |
1304 | ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def)); | |
1305 | ||
1306 | /* If definition is in current bb, it is fine. */ | |
1307 | if (bb == def_bb) | |
1308 | ; | |
1309 | /* If definition bb doesn't dominate the current bb, | |
1310 | it can't be used. */ | |
1311 | else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb)) | |
1312 | def = NULL; | |
1313 | /* If there is just one definition and dominates the current | |
1314 | bb, it is fine. */ | |
74105c0d | 1315 | else if (info->need_phi_state == NEED_PHI_STATE_NO) |
4ae5778c | 1316 | ; |
1317 | else | |
824651eb | 1318 | { |
04009ada | 1319 | def_blocks *db_p = get_def_blocks_for (info); |
824651eb | 1320 | |
4ae5778c | 1321 | /* If there are some non-debug uses in the current bb, |
1322 | it is fine. */ | |
1323 | if (bitmap_bit_p (db_p->livein_blocks, bb->index)) | |
824651eb | 1324 | ; |
4ae5778c | 1325 | /* Otherwise give up for now. */ |
824651eb | 1326 | else |
4ae5778c | 1327 | def = NULL; |
824651eb | 1328 | } |
1329 | } | |
841424cc | 1330 | if (def == NULL) |
1331 | { | |
1332 | gimple_debug_bind_reset_value (stmt); | |
1333 | update_stmt (stmt); | |
1334 | return; | |
1335 | } | |
1336 | SET_USE (use_p, def); | |
1337 | } | |
1338 | if (update) | |
1339 | update_stmt (stmt); | |
1340 | } | |
1341 | ||
e551bd1a | 1342 | /* SSA Rewriting Step 2. Rewrite every variable used in each statement in |
1343 | the block with its immediate reaching definitions. Update the current | |
1344 | definition of a variable when a new real or virtual definition is found. */ | |
f3d9a16c | 1345 | |
1346 | static void | |
eb54054d | 1347 | rewrite_stmt (gimple_stmt_iterator *si) |
f3d9a16c | 1348 | { |
e551bd1a | 1349 | use_operand_p use_p; |
1350 | def_operand_p def_p; | |
1351 | ssa_op_iter iter; | |
42acab1c | 1352 | gimple *stmt = gsi_stmt (*si); |
e551bd1a | 1353 | |
e551bd1a | 1354 | /* If mark_def_sites decided that we don't need to rewrite this |
1355 | statement, ignore it. */ | |
2920559d | 1356 | gcc_assert (blocks_to_update == NULL); |
75a70cf9 | 1357 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
e551bd1a | 1358 | return; |
f3d9a16c | 1359 | |
1360 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
e551bd1a | 1361 | { |
1362 | fprintf (dump_file, "Renaming statement "); | |
75a70cf9 | 1363 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
e551bd1a | 1364 | fprintf (dump_file, "\n"); |
1365 | } | |
f3d9a16c | 1366 | |
4fb5e5ca | 1367 | /* Step 1. Rewrite USES in the statement. */ |
75a70cf9 | 1368 | if (rewrite_uses_p (stmt)) |
841424cc | 1369 | { |
1370 | if (is_gimple_debug (stmt)) | |
1371 | rewrite_debug_stmt_uses (stmt); | |
1372 | else | |
5aabc5f2 | 1373 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) |
841424cc | 1374 | { |
1375 | tree var = USE_FROM_PTR (use_p); | |
9ae1b28a | 1376 | if (TREE_CODE (var) == SSA_NAME) |
1377 | continue; | |
88536563 | 1378 | gcc_checking_assert (DECL_P (var)); |
841424cc | 1379 | SET_USE (use_p, get_reaching_def (var)); |
1380 | } | |
1381 | } | |
f3d9a16c | 1382 | |
4fb5e5ca | 1383 | /* Step 2. Register the statement's DEF operands. */ |
75a70cf9 | 1384 | if (register_defs_p (stmt)) |
5aabc5f2 | 1385 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
88dbf20f | 1386 | { |
1387 | tree var = DEF_FROM_PTR (def_p); | |
eb54054d | 1388 | tree name; |
9845d120 | 1389 | tree tracked_var; |
eb54054d | 1390 | |
9ae1b28a | 1391 | if (TREE_CODE (var) == SSA_NAME) |
1392 | continue; | |
88536563 | 1393 | gcc_checking_assert (DECL_P (var)); |
eb54054d | 1394 | |
1395 | if (gimple_clobber_p (stmt) | |
1396 | && is_gimple_reg (var)) | |
1397 | { | |
1398 | /* If we rewrite a DECL into SSA form then drop its | |
1399 | clobber stmts and replace uses with a new default def. */ | |
53e9c5c4 | 1400 | gcc_checking_assert (VAR_P (var) && !gimple_vdef (stmt)); |
eb54054d | 1401 | gsi_replace (si, gimple_build_nop (), true); |
1402 | register_new_def (get_or_create_ssa_default_def (cfun, var), var); | |
1403 | break; | |
1404 | } | |
1405 | ||
1406 | name = make_ssa_name (var, stmt); | |
9845d120 | 1407 | SET_DEF (def_p, name); |
4fb5e5ca | 1408 | register_new_def (DEF_FROM_PTR (def_p), var); |
9845d120 | 1409 | |
1410 | tracked_var = target_for_debug_bind (var); | |
1411 | if (tracked_var) | |
1412 | { | |
42acab1c | 1413 | gimple *note = gimple_build_debug_bind (tracked_var, name, stmt); |
eb54054d | 1414 | gsi_insert_after (si, note, GSI_SAME_STMT); |
9845d120 | 1415 | } |
88dbf20f | 1416 | } |
f3d9a16c | 1417 | } |
4ee9c684 | 1418 | |
e551bd1a | 1419 | |
4ee9c684 | 1420 | /* SSA Rewriting Step 3. Visit all the successor blocks of BB looking for |
1421 | PHI nodes. For every PHI node found, add a new argument containing the | |
1422 | current reaching definition for the variable and the edge through which | |
dac49aa5 | 1423 | that definition is reaching the PHI node. */ |
4ee9c684 | 1424 | |
1425 | static void | |
6bf320fb | 1426 | rewrite_add_phi_arguments (basic_block bb) |
4ee9c684 | 1427 | { |
1428 | edge e; | |
cd665a06 | 1429 | edge_iterator ei; |
4ee9c684 | 1430 | |
cd665a06 | 1431 | FOR_EACH_EDGE (e, ei, bb->succs) |
4ee9c684 | 1432 | { |
1a91d914 | 1433 | gphi *phi; |
1434 | gphi_iterator gsi; | |
4ee9c684 | 1435 | |
75a70cf9 | 1436 | for (gsi = gsi_start_phis (e->dest); !gsi_end_p (gsi); |
1437 | gsi_next (&gsi)) | |
4ee9c684 | 1438 | { |
8416d774 | 1439 | tree currdef, res; |
e60062ea | 1440 | location_t loc; |
efbcb6de | 1441 | |
1a91d914 | 1442 | phi = gsi.phi (); |
e60062ea | 1443 | res = gimple_phi_result (phi); |
8416d774 | 1444 | currdef = get_reaching_def (SSA_NAME_VAR (res)); |
e60062ea | 1445 | /* Virtual operand PHI args do not need a location. */ |
1446 | if (virtual_operand_p (res)) | |
1447 | loc = UNKNOWN_LOCATION; | |
1448 | else | |
1449 | loc = gimple_location (SSA_NAME_DEF_STMT (currdef)); | |
1450 | add_phi_arg (phi, currdef, e, loc); | |
4ee9c684 | 1451 | } |
1452 | } | |
1453 | } | |
1454 | ||
54c91640 | 1455 | class rewrite_dom_walker : public dom_walker |
1456 | { | |
1457 | public: | |
11b3ff74 | 1458 | rewrite_dom_walker (cdi_direction direction) |
1459 | : dom_walker (direction, ALL_BLOCKS, NULL) {} | |
54c91640 | 1460 | |
96752458 | 1461 | virtual edge before_dom_children (basic_block); |
54c91640 | 1462 | virtual void after_dom_children (basic_block); |
1463 | }; | |
1464 | ||
6bf320fb | 1465 | /* SSA Rewriting Step 1. Initialization, create a block local stack |
1466 | of reaching definitions for new SSA names produced in this block | |
1467 | (BLOCK_DEFS). Register new definitions for every PHI node in the | |
1468 | block. */ | |
1469 | ||
96752458 | 1470 | edge |
54c91640 | 1471 | rewrite_dom_walker::before_dom_children (basic_block bb) |
6bf320fb | 1472 | { |
6bf320fb | 1473 | if (dump_file && (dump_flags & TDF_DETAILS)) |
1474 | fprintf (dump_file, "\n\nRenaming block #%d\n\n", bb->index); | |
1475 | ||
1476 | /* Mark the unwind point for this block. */ | |
f1f41a6c | 1477 | block_defs_stack.safe_push (NULL_TREE); |
6bf320fb | 1478 | |
1479 | /* Step 1. Register new definitions for every PHI node in the block. | |
1480 | Conceptually, all the PHI nodes are executed in parallel and each PHI | |
1481 | node introduces a new version for the associated variable. */ | |
1a91d914 | 1482 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
1483 | gsi_next (&gsi)) | |
6bf320fb | 1484 | { |
5aabc5f2 | 1485 | tree result = gimple_phi_result (gsi_stmt (gsi)); |
6bf320fb | 1486 | register_new_def (result, SSA_NAME_VAR (result)); |
1487 | } | |
1488 | ||
1489 | /* Step 2. Rewrite every variable used in each statement in the block | |
1490 | with its immediate reaching definitions. Update the current definition | |
1491 | of a variable when a new real or virtual definition is found. */ | |
08b7917c | 1492 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
1a91d914 | 1493 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); |
1494 | gsi_next (&gsi)) | |
eb54054d | 1495 | rewrite_stmt (&gsi); |
6bf320fb | 1496 | |
1497 | /* Step 3. Visit all the successor blocks of BB looking for PHI nodes. | |
1498 | For every PHI node found, add a new argument containing the current | |
1499 | reaching definition for the variable and the edge through which that | |
1500 | definition is reaching the PHI node. */ | |
1501 | rewrite_add_phi_arguments (bb); | |
96752458 | 1502 | |
1503 | return NULL; | |
6bf320fb | 1504 | } |
1505 | ||
1506 | ||
e551bd1a | 1507 | |
4fb5e5ca | 1508 | /* Called after visiting all the statements in basic block BB and all |
1509 | of its dominator children. Restore CURRDEFS to its original value. */ | |
4ee9c684 | 1510 | |
54c91640 | 1511 | void |
1512 | rewrite_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
4ee9c684 | 1513 | { |
dd2d357d | 1514 | /* Restore CURRDEFS to its original state. */ |
f1f41a6c | 1515 | while (block_defs_stack.length () > 0) |
4ee9c684 | 1516 | { |
f1f41a6c | 1517 | tree tmp = block_defs_stack.pop (); |
4ee9c684 | 1518 | tree saved_def, var; |
1519 | ||
dd2d357d | 1520 | if (tmp == NULL_TREE) |
1521 | break; | |
1522 | ||
4ee9c684 | 1523 | if (TREE_CODE (tmp) == SSA_NAME) |
1524 | { | |
4fb5e5ca | 1525 | /* If we recorded an SSA_NAME, then make the SSA_NAME the |
1526 | current definition of its underlying variable. Note that | |
1527 | if the SSA_NAME is not for a GIMPLE register, the symbol | |
1528 | being defined is stored in the next slot in the stack. | |
1529 | This mechanism is needed because an SSA name for a | |
1530 | non-register symbol may be the definition for more than | |
1531 | one symbol (e.g., SFTs, aliased variables, etc). */ | |
4ee9c684 | 1532 | saved_def = tmp; |
1533 | var = SSA_NAME_VAR (saved_def); | |
4fb5e5ca | 1534 | if (!is_gimple_reg (var)) |
f1f41a6c | 1535 | var = block_defs_stack.pop (); |
4ee9c684 | 1536 | } |
1537 | else | |
1538 | { | |
4fb5e5ca | 1539 | /* If we recorded anything else, it must have been a _DECL |
1540 | node and its current reaching definition must have been | |
1541 | NULL. */ | |
4ee9c684 | 1542 | saved_def = NULL; |
1543 | var = tmp; | |
1544 | } | |
48e1416a | 1545 | |
74105c0d | 1546 | get_common_info (var)->current_def = saved_def; |
4ee9c684 | 1547 | } |
1548 | } | |
1549 | ||
1550 | ||
4fb5e5ca | 1551 | /* Dump bitmap SET (assumed to contain VAR_DECLs) to FILE. */ |
1552 | ||
4b987fac | 1553 | DEBUG_FUNCTION void |
4fb5e5ca | 1554 | debug_decl_set (bitmap set) |
1555 | { | |
1556 | dump_decl_set (stderr, set); | |
dd277d48 | 1557 | fprintf (stderr, "\n"); |
4fb5e5ca | 1558 | } |
1559 | ||
1560 | ||
1561 | /* Dump the renaming stack (block_defs_stack) to FILE. Traverse the | |
1562 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1563 | dumped. New levels are created when the dominator tree traversal | |
1564 | used for renaming enters a new sub-tree. */ | |
1565 | ||
1566 | void | |
1567 | dump_defs_stack (FILE *file, int n) | |
1568 | { | |
1569 | int i, j; | |
1570 | ||
1571 | fprintf (file, "\n\nRenaming stack"); | |
1572 | if (n > 0) | |
1573 | fprintf (file, " (up to %d levels)", n); | |
1574 | fprintf (file, "\n\n"); | |
1575 | ||
1576 | i = 1; | |
1577 | fprintf (file, "Level %d (current level)\n", i); | |
f1f41a6c | 1578 | for (j = (int) block_defs_stack.length () - 1; j >= 0; j--) |
4fb5e5ca | 1579 | { |
1580 | tree name, var; | |
48e1416a | 1581 | |
f1f41a6c | 1582 | name = block_defs_stack[j]; |
4fb5e5ca | 1583 | if (name == NULL_TREE) |
1584 | { | |
1585 | i++; | |
1586 | if (n > 0 && i > n) | |
1587 | break; | |
1588 | fprintf (file, "\nLevel %d\n", i); | |
1589 | continue; | |
1590 | } | |
1591 | ||
1592 | if (DECL_P (name)) | |
1593 | { | |
1594 | var = name; | |
1595 | name = NULL_TREE; | |
1596 | } | |
1597 | else | |
1598 | { | |
1599 | var = SSA_NAME_VAR (name); | |
1600 | if (!is_gimple_reg (var)) | |
1601 | { | |
1602 | j--; | |
f1f41a6c | 1603 | var = block_defs_stack[j]; |
4fb5e5ca | 1604 | } |
1605 | } | |
1606 | ||
1607 | fprintf (file, " Previous CURRDEF ("); | |
1ffa4346 | 1608 | print_generic_expr (file, var); |
4fb5e5ca | 1609 | fprintf (file, ") = "); |
1610 | if (name) | |
1ffa4346 | 1611 | print_generic_expr (file, name); |
4fb5e5ca | 1612 | else |
1613 | fprintf (file, "<NIL>"); | |
1614 | fprintf (file, "\n"); | |
1615 | } | |
1616 | } | |
1617 | ||
1618 | ||
1619 | /* Dump the renaming stack (block_defs_stack) to stderr. Traverse the | |
1620 | stack up to a maximum of N levels. If N is -1, the whole stack is | |
1621 | dumped. New levels are created when the dominator tree traversal | |
1622 | used for renaming enters a new sub-tree. */ | |
1623 | ||
4b987fac | 1624 | DEBUG_FUNCTION void |
4fb5e5ca | 1625 | debug_defs_stack (int n) |
1626 | { | |
1627 | dump_defs_stack (stderr, n); | |
1628 | } | |
1629 | ||
1630 | ||
1631 | /* Dump the current reaching definition of every symbol to FILE. */ | |
1632 | ||
1633 | void | |
1634 | dump_currdefs (FILE *file) | |
1635 | { | |
e70e8b13 | 1636 | unsigned i; |
4fb5e5ca | 1637 | tree var; |
1638 | ||
f1f41a6c | 1639 | if (symbols_to_rename.is_empty ()) |
e70e8b13 | 1640 | return; |
1641 | ||
4fb5e5ca | 1642 | fprintf (file, "\n\nCurrent reaching definitions\n\n"); |
f1f41a6c | 1643 | FOR_EACH_VEC_ELT (symbols_to_rename, i, var) |
e70e8b13 | 1644 | { |
04009ada | 1645 | common_info *info = get_common_info (var); |
e70e8b13 | 1646 | fprintf (file, "CURRDEF ("); |
1ffa4346 | 1647 | print_generic_expr (file, var); |
e70e8b13 | 1648 | fprintf (file, ") = "); |
74105c0d | 1649 | if (info->current_def) |
1ffa4346 | 1650 | print_generic_expr (file, info->current_def); |
e70e8b13 | 1651 | else |
1652 | fprintf (file, "<NIL>"); | |
1653 | fprintf (file, "\n"); | |
1654 | } | |
4fb5e5ca | 1655 | } |
1656 | ||
1657 | ||
1658 | /* Dump the current reaching definition of every symbol to stderr. */ | |
1659 | ||
4b987fac | 1660 | DEBUG_FUNCTION void |
4fb5e5ca | 1661 | debug_currdefs (void) |
1662 | { | |
1663 | dump_currdefs (stderr); | |
1664 | } | |
1665 | ||
1666 | ||
4ee9c684 | 1667 | /* Dump SSA information to FILE. */ |
1668 | ||
1669 | void | |
1670 | dump_tree_ssa (FILE *file) | |
1671 | { | |
4ee9c684 | 1672 | const char *funcname |
5135beeb | 1673 | = lang_hooks.decl_printable_name (current_function_decl, 2); |
4ee9c684 | 1674 | |
4fb5e5ca | 1675 | fprintf (file, "SSA renaming information for %s\n\n", funcname); |
4ee9c684 | 1676 | |
22d6c74e | 1677 | dump_var_infos (file); |
4fb5e5ca | 1678 | dump_defs_stack (file, -1); |
1679 | dump_currdefs (file); | |
1680 | dump_tree_ssa_stats (file); | |
4ee9c684 | 1681 | } |
1682 | ||
1683 | ||
1684 | /* Dump SSA information to stderr. */ | |
1685 | ||
4b987fac | 1686 | DEBUG_FUNCTION void |
4ee9c684 | 1687 | debug_tree_ssa (void) |
1688 | { | |
1689 | dump_tree_ssa (stderr); | |
1690 | } | |
1691 | ||
1692 | ||
e551bd1a | 1693 | /* Dump statistics for the hash table HTAB. */ |
1694 | ||
1695 | static void | |
c1f445d2 | 1696 | htab_statistics (FILE *file, const hash_table<var_info_hasher> &htab) |
e551bd1a | 1697 | { |
1698 | fprintf (file, "size %ld, %ld elements, %f collision/search ratio\n", | |
3e871d4d | 1699 | (long) htab.size (), |
1700 | (long) htab.elements (), | |
1701 | htab.collisions ()); | |
e551bd1a | 1702 | } |
1703 | ||
1704 | ||
4ee9c684 | 1705 | /* Dump SSA statistics on FILE. */ |
1706 | ||
1707 | void | |
1708 | dump_tree_ssa_stats (FILE *file) | |
1709 | { | |
c1f445d2 | 1710 | if (var_infos) |
4fb5e5ca | 1711 | { |
22d6c74e | 1712 | fprintf (file, "\nHash table statistics:\n"); |
1713 | fprintf (file, " var_infos: "); | |
c1f445d2 | 1714 | htab_statistics (file, *var_infos); |
22d6c74e | 1715 | fprintf (file, "\n"); |
4fb5e5ca | 1716 | } |
4ee9c684 | 1717 | } |
1718 | ||
1719 | ||
1720 | /* Dump SSA statistics on stderr. */ | |
1721 | ||
4b987fac | 1722 | DEBUG_FUNCTION void |
4ee9c684 | 1723 | debug_tree_ssa_stats (void) |
1724 | { | |
1725 | dump_tree_ssa_stats (stderr); | |
1726 | } | |
1727 | ||
1728 | ||
22d6c74e | 1729 | /* Callback for htab_traverse to dump the VAR_INFOS hash table. */ |
4ee9c684 | 1730 | |
3e871d4d | 1731 | int |
04009ada | 1732 | debug_var_infos_r (var_info **slot, FILE *file) |
e551bd1a | 1733 | { |
04009ada | 1734 | var_info *info = *slot; |
48e1416a | 1735 | |
4fb5e5ca | 1736 | fprintf (file, "VAR: "); |
74105c0d | 1737 | print_generic_expr (file, info->var, dump_flags); |
1738 | bitmap_print (file, info->info.def_blocks.def_blocks, | |
1739 | ", DEF_BLOCKS: { ", "}"); | |
1740 | bitmap_print (file, info->info.def_blocks.livein_blocks, | |
1741 | ", LIVEIN_BLOCKS: { ", "}"); | |
1742 | bitmap_print (file, info->info.def_blocks.phi_blocks, | |
1743 | ", PHI_BLOCKS: { ", "}\n"); | |
4ee9c684 | 1744 | |
e551bd1a | 1745 | return 1; |
1746 | } | |
4ee9c684 | 1747 | |
4ee9c684 | 1748 | |
22d6c74e | 1749 | /* Dump the VAR_INFOS hash table on FILE. */ |
4fb5e5ca | 1750 | |
1751 | void | |
22d6c74e | 1752 | dump_var_infos (FILE *file) |
4fb5e5ca | 1753 | { |
1754 | fprintf (file, "\n\nDefinition and live-in blocks:\n\n"); | |
c1f445d2 | 1755 | if (var_infos) |
1756 | var_infos->traverse <FILE *, debug_var_infos_r> (file); | |
4fb5e5ca | 1757 | } |
1758 | ||
1759 | ||
22d6c74e | 1760 | /* Dump the VAR_INFOS hash table on stderr. */ |
4ee9c684 | 1761 | |
4b987fac | 1762 | DEBUG_FUNCTION void |
22d6c74e | 1763 | debug_var_infos (void) |
e551bd1a | 1764 | { |
22d6c74e | 1765 | dump_var_infos (stderr); |
e551bd1a | 1766 | } |
4ee9c684 | 1767 | |
f3d9a16c | 1768 | |
88dbf20f | 1769 | /* Register NEW_NAME to be the new reaching definition for OLD_NAME. */ |
4ee9c684 | 1770 | |
88dbf20f | 1771 | static inline void |
1772 | register_new_update_single (tree new_name, tree old_name) | |
1773 | { | |
04009ada | 1774 | common_info *info = get_common_info (old_name); |
74105c0d | 1775 | tree currdef = info->current_def; |
f3d9a16c | 1776 | |
4fb5e5ca | 1777 | /* Push the current reaching definition into BLOCK_DEFS_STACK. |
88dbf20f | 1778 | This stack is later used by the dominator tree callbacks to |
1779 | restore the reaching definitions for all the variables | |
1780 | defined in the block after a recursive visit to all its | |
1781 | immediately dominated blocks. */ | |
f1f41a6c | 1782 | block_defs_stack.reserve (2); |
1783 | block_defs_stack.quick_push (currdef); | |
1784 | block_defs_stack.quick_push (old_name); | |
f3d9a16c | 1785 | |
88dbf20f | 1786 | /* Set the current reaching definition for OLD_NAME to be |
1787 | NEW_NAME. */ | |
74105c0d | 1788 | info->current_def = new_name; |
88dbf20f | 1789 | } |
e551bd1a | 1790 | |
4ee9c684 | 1791 | |
88dbf20f | 1792 | /* Register NEW_NAME to be the new reaching definition for all the |
1793 | names in OLD_NAMES. Used by the incremental SSA update routines to | |
1794 | replace old SSA names with new ones. */ | |
e551bd1a | 1795 | |
88dbf20f | 1796 | static inline void |
1797 | register_new_update_set (tree new_name, bitmap old_names) | |
1798 | { | |
1799 | bitmap_iterator bi; | |
1800 | unsigned i; | |
e551bd1a | 1801 | |
88dbf20f | 1802 | EXECUTE_IF_SET_IN_BITMAP (old_names, 0, i, bi) |
1803 | register_new_update_single (new_name, ssa_name (i)); | |
4ee9c684 | 1804 | } |
1805 | ||
e551bd1a | 1806 | |
88dbf20f | 1807 | |
095dcfa3 | 1808 | /* If the operand pointed to by USE_P is a name in OLD_SSA_NAMES or |
1809 | it is a symbol marked for renaming, replace it with USE_P's current | |
1810 | reaching definition. */ | |
1811 | ||
1812 | static inline void | |
1813 | maybe_replace_use (use_operand_p use_p) | |
1814 | { | |
1815 | tree rdef = NULL_TREE; | |
1816 | tree use = USE_FROM_PTR (use_p); | |
1817 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1818 | ||
e70e8b13 | 1819 | if (marked_for_renaming (sym)) |
095dcfa3 | 1820 | rdef = get_reaching_def (sym); |
1821 | else if (is_old_name (use)) | |
1822 | rdef = get_reaching_def (use); | |
1823 | ||
1824 | if (rdef && rdef != use) | |
1825 | SET_USE (use_p, rdef); | |
1826 | } | |
1827 | ||
1828 | ||
9845d120 | 1829 | /* Same as maybe_replace_use, but without introducing default stmts, |
1830 | returning false to indicate a need to do so. */ | |
1831 | ||
1832 | static inline bool | |
1833 | maybe_replace_use_in_debug_stmt (use_operand_p use_p) | |
1834 | { | |
1835 | tree rdef = NULL_TREE; | |
1836 | tree use = USE_FROM_PTR (use_p); | |
1837 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); | |
1838 | ||
e70e8b13 | 1839 | if (marked_for_renaming (sym)) |
74105c0d | 1840 | rdef = get_var_info (sym)->info.current_def; |
9845d120 | 1841 | else if (is_old_name (use)) |
1842 | { | |
74105c0d | 1843 | rdef = get_ssa_name_ann (use)->info.current_def; |
9845d120 | 1844 | /* We can't assume that, if there's no current definition, the |
1845 | default one should be used. It could be the case that we've | |
1846 | rearranged blocks so that the earlier definition no longer | |
1847 | dominates the use. */ | |
1848 | if (!rdef && SSA_NAME_IS_DEFAULT_DEF (use)) | |
1849 | rdef = use; | |
1850 | } | |
1851 | else | |
1852 | rdef = use; | |
1853 | ||
1854 | if (rdef && rdef != use) | |
1855 | SET_USE (use_p, rdef); | |
1856 | ||
1857 | return rdef != NULL_TREE; | |
1858 | } | |
1859 | ||
1860 | ||
ba39c1d4 | 1861 | /* If DEF has x_5 = ASAN_POISON () as its current def, add |
1862 | ASAN_POISON_USE (x_5) stmt before GSI to denote the stmt writes into | |
1863 | a poisoned (out of scope) variable. */ | |
1864 | ||
1865 | static void | |
1866 | maybe_add_asan_poison_write (tree def, gimple_stmt_iterator *gsi) | |
1867 | { | |
1868 | tree cdef = get_current_def (def); | |
1869 | if (cdef != NULL | |
1870 | && TREE_CODE (cdef) == SSA_NAME | |
1871 | && gimple_call_internal_p (SSA_NAME_DEF_STMT (cdef), IFN_ASAN_POISON)) | |
1872 | { | |
1873 | gcall *call | |
1874 | = gimple_build_call_internal (IFN_ASAN_POISON_USE, 1, cdef); | |
1875 | gimple_set_location (call, gimple_location (gsi_stmt (*gsi))); | |
1876 | gsi_insert_before (gsi, call, GSI_SAME_STMT); | |
1877 | } | |
1878 | } | |
1879 | ||
1880 | ||
095dcfa3 | 1881 | /* If the operand pointed to by DEF_P is an SSA name in NEW_SSA_NAMES |
1882 | or OLD_SSA_NAMES, or if it is a symbol marked for renaming, | |
1883 | register it as the current definition for the names replaced by | |
4d8d655b | 1884 | DEF_P. Returns whether the statement should be removed. */ |
095dcfa3 | 1885 | |
4d8d655b | 1886 | static inline bool |
42acab1c | 1887 | maybe_register_def (def_operand_p def_p, gimple *stmt, |
cd610ee6 | 1888 | gimple_stmt_iterator gsi) |
095dcfa3 | 1889 | { |
1890 | tree def = DEF_FROM_PTR (def_p); | |
1891 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); | |
4d8d655b | 1892 | bool to_delete = false; |
095dcfa3 | 1893 | |
4fb5e5ca | 1894 | /* If DEF is a naked symbol that needs renaming, create a new |
1895 | name for it. */ | |
e70e8b13 | 1896 | if (marked_for_renaming (sym)) |
095dcfa3 | 1897 | { |
1898 | if (DECL_P (def)) | |
1899 | { | |
4d8d655b | 1900 | if (gimple_clobber_p (stmt) && is_gimple_reg (sym)) |
1901 | { | |
53e9c5c4 | 1902 | gcc_checking_assert (VAR_P (sym)); |
4d8d655b | 1903 | /* Replace clobber stmts with a default def. This new use of a |
1904 | default definition may make it look like SSA_NAMEs have | |
1905 | conflicting lifetimes, so we need special code to let them | |
1906 | coalesce properly. */ | |
1907 | to_delete = true; | |
1908 | def = get_or_create_ssa_default_def (cfun, sym); | |
1909 | } | |
1910 | else | |
ba39c1d4 | 1911 | { |
1912 | if (asan_sanitize_use_after_scope ()) | |
1913 | maybe_add_asan_poison_write (def, &gsi); | |
1914 | def = make_ssa_name (def, stmt); | |
1915 | } | |
095dcfa3 | 1916 | SET_DEF (def_p, def); |
cd610ee6 | 1917 | |
4d8d655b | 1918 | tree tracked_var = target_for_debug_bind (sym); |
cd610ee6 | 1919 | if (tracked_var) |
1920 | { | |
42acab1c | 1921 | gimple *note = gimple_build_debug_bind (tracked_var, def, stmt); |
8d7f27c3 | 1922 | /* If stmt ends the bb, insert the debug stmt on the single |
1923 | non-EH edge from the stmt. */ | |
1924 | if (gsi_one_before_end_p (gsi) && stmt_ends_bb_p (stmt)) | |
1925 | { | |
1926 | basic_block bb = gsi_bb (gsi); | |
1927 | edge_iterator ei; | |
1928 | edge e, ef = NULL; | |
1929 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1930 | if (!(e->flags & EDGE_EH)) | |
1931 | { | |
88536563 | 1932 | gcc_checking_assert (!ef); |
8d7f27c3 | 1933 | ef = e; |
1934 | } | |
36a2709b | 1935 | /* If there are other predecessors to ef->dest, then |
1936 | there must be PHI nodes for the modified | |
1937 | variable, and therefore there will be debug bind | |
1938 | stmts after the PHI nodes. The debug bind notes | |
1939 | we'd insert would force the creation of a new | |
1940 | block (diverging codegen) and be redundant with | |
1941 | the post-PHI bind stmts, so don't add them. | |
1942 | ||
1943 | As for the exit edge, there wouldn't be redundant | |
1944 | bind stmts, but there wouldn't be a PC to bind | |
1945 | them to either, so avoid diverging the CFG. */ | |
1946 | if (ef && single_pred_p (ef->dest) | |
34154e27 | 1947 | && ef->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
36a2709b | 1948 | { |
1949 | /* If there were PHI nodes in the node, we'd | |
1950 | have to make sure the value we're binding | |
1951 | doesn't need rewriting. But there shouldn't | |
1952 | be PHI nodes in a single-predecessor block, | |
1953 | so we just add the note. */ | |
1954 | gsi_insert_on_edge_immediate (ef, note); | |
1955 | } | |
8d7f27c3 | 1956 | } |
1957 | else | |
1958 | gsi_insert_after (&gsi, note, GSI_SAME_STMT); | |
cd610ee6 | 1959 | } |
095dcfa3 | 1960 | } |
1961 | ||
1962 | register_new_update_single (def, sym); | |
1963 | } | |
1964 | else | |
1965 | { | |
1966 | /* If DEF is a new name, register it as a new definition | |
1967 | for all the names replaced by DEF. */ | |
1968 | if (is_new_name (def)) | |
1969 | register_new_update_set (def, names_replaced_by (def)); | |
1970 | ||
1971 | /* If DEF is an old name, register DEF as a new | |
1972 | definition for itself. */ | |
1973 | if (is_old_name (def)) | |
1974 | register_new_update_single (def, def); | |
1975 | } | |
4d8d655b | 1976 | |
1977 | return to_delete; | |
095dcfa3 | 1978 | } |
1979 | ||
1980 | ||
88dbf20f | 1981 | /* Update every variable used in the statement pointed-to by SI. The |
1982 | statement is assumed to be in SSA form already. Names in | |
1983 | OLD_SSA_NAMES used by SI will be updated to their current reaching | |
1984 | definition. Names in OLD_SSA_NAMES or NEW_SSA_NAMES defined by SI | |
1985 | will be registered as a new definition for their corresponding name | |
4d8d655b | 1986 | in OLD_SSA_NAMES. Returns whether STMT should be removed. */ |
88dbf20f | 1987 | |
4d8d655b | 1988 | static bool |
42acab1c | 1989 | rewrite_update_stmt (gimple *stmt, gimple_stmt_iterator gsi) |
88dbf20f | 1990 | { |
88dbf20f | 1991 | use_operand_p use_p; |
1992 | def_operand_p def_p; | |
1993 | ssa_op_iter iter; | |
1994 | ||
88dbf20f | 1995 | /* Only update marked statements. */ |
75a70cf9 | 1996 | if (!rewrite_uses_p (stmt) && !register_defs_p (stmt)) |
4d8d655b | 1997 | return false; |
88dbf20f | 1998 | |
1999 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
2000 | { | |
2001 | fprintf (dump_file, "Updating SSA information for statement "); | |
75a70cf9 | 2002 | print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); |
88dbf20f | 2003 | } |
2004 | ||
2005 | /* Rewrite USES included in OLD_SSA_NAMES and USES whose underlying | |
2006 | symbol is marked for renaming. */ | |
75a70cf9 | 2007 | if (rewrite_uses_p (stmt)) |
9845d120 | 2008 | { |
2009 | if (is_gimple_debug (stmt)) | |
2010 | { | |
2011 | bool failed = false; | |
2012 | ||
2013 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
2014 | if (!maybe_replace_use_in_debug_stmt (use_p)) | |
2015 | { | |
2016 | failed = true; | |
2017 | break; | |
2018 | } | |
2019 | ||
2020 | if (failed) | |
2021 | { | |
2022 | /* DOM sometimes threads jumps in such a way that a | |
2023 | debug stmt ends up referencing a SSA variable that no | |
2024 | longer dominates the debug stmt, but such that all | |
2025 | incoming definitions refer to the same definition in | |
2026 | an earlier dominator. We could try to recover that | |
2027 | definition somehow, but this will have to do for now. | |
2028 | ||
2029 | Introducing a default definition, which is what | |
2030 | maybe_replace_use() would do in such cases, may | |
2031 | modify code generation, for the otherwise-unused | |
2032 | default definition would never go away, modifying SSA | |
2033 | version numbers all over. */ | |
2034 | gimple_debug_bind_reset_value (stmt); | |
2035 | update_stmt (stmt); | |
2036 | } | |
2037 | } | |
2038 | else | |
2039 | { | |
2040 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_ALL_USES) | |
2041 | maybe_replace_use (use_p); | |
2042 | } | |
2043 | } | |
88dbf20f | 2044 | |
2045 | /* Register definitions of names in NEW_SSA_NAMES and OLD_SSA_NAMES. | |
2046 | Also register definitions for names whose underlying symbol is | |
2047 | marked for renaming. */ | |
4d8d655b | 2048 | bool to_delete = false; |
75a70cf9 | 2049 | if (register_defs_p (stmt)) |
dd277d48 | 2050 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, iter, SSA_OP_ALL_DEFS) |
4d8d655b | 2051 | to_delete |= maybe_register_def (def_p, stmt, gsi); |
2052 | ||
2053 | return to_delete; | |
88dbf20f | 2054 | } |
2055 | ||
2056 | ||
2057 | /* Visit all the successor blocks of BB looking for PHI nodes. For | |
2058 | every PHI node found, check if any of its arguments is in | |
2059 | OLD_SSA_NAMES. If so, and if the argument has a current reaching | |
2060 | definition, replace it. */ | |
2061 | ||
2062 | static void | |
6bf320fb | 2063 | rewrite_update_phi_arguments (basic_block bb) |
88dbf20f | 2064 | { |
2065 | edge e; | |
2066 | edge_iterator ei; | |
70630fcd | 2067 | unsigned i; |
88dbf20f | 2068 | |
2069 | FOR_EACH_EDGE (e, ei, bb->succs) | |
2070 | { | |
1a91d914 | 2071 | gphi *phi; |
2072 | vec<gphi *> phis; | |
88dbf20f | 2073 | |
70630fcd | 2074 | if (!bitmap_bit_p (blocks_with_phis_to_rewrite, e->dest->index)) |
2075 | continue; | |
48e1416a | 2076 | |
f1f41a6c | 2077 | phis = phis_to_rewrite[e->dest->index]; |
2078 | FOR_EACH_VEC_ELT (phis, i, phi) | |
88dbf20f | 2079 | { |
efbcb6de | 2080 | tree arg, lhs_sym, reaching_def = NULL; |
88dbf20f | 2081 | use_operand_p arg_p; |
2082 | ||
88536563 | 2083 | gcc_checking_assert (rewrite_uses_p (phi)); |
88dbf20f | 2084 | |
2085 | arg_p = PHI_ARG_DEF_PTR_FROM_EDGE (phi, e); | |
2086 | arg = USE_FROM_PTR (arg_p); | |
2087 | ||
2088 | if (arg && !DECL_P (arg) && TREE_CODE (arg) != SSA_NAME) | |
2089 | continue; | |
2090 | ||
75a70cf9 | 2091 | lhs_sym = SSA_NAME_VAR (gimple_phi_result (phi)); |
4fb5e5ca | 2092 | |
88dbf20f | 2093 | if (arg == NULL_TREE) |
2094 | { | |
2095 | /* When updating a PHI node for a recently introduced | |
2096 | symbol we may find NULL arguments. That's why we | |
2097 | take the symbol from the LHS of the PHI node. */ | |
efbcb6de | 2098 | reaching_def = get_reaching_def (lhs_sym); |
2099 | ||
88dbf20f | 2100 | } |
2101 | else | |
2102 | { | |
2103 | tree sym = DECL_P (arg) ? arg : SSA_NAME_VAR (arg); | |
2104 | ||
e70e8b13 | 2105 | if (marked_for_renaming (sym)) |
efbcb6de | 2106 | reaching_def = get_reaching_def (sym); |
88dbf20f | 2107 | else if (is_old_name (arg)) |
efbcb6de | 2108 | reaching_def = get_reaching_def (arg); |
2109 | } | |
2110 | ||
2111 | /* Update the argument if there is a reaching def. */ | |
2112 | if (reaching_def) | |
2113 | { | |
be1e7283 | 2114 | location_t locus; |
efbcb6de | 2115 | int arg_i = PHI_ARG_INDEX_FROM_USE (arg_p); |
2116 | ||
2117 | SET_USE (arg_p, reaching_def); | |
efbcb6de | 2118 | |
e60062ea | 2119 | /* Virtual operands do not need a location. */ |
2120 | if (virtual_operand_p (reaching_def)) | |
2121 | locus = UNKNOWN_LOCATION; | |
efbcb6de | 2122 | else |
e60062ea | 2123 | { |
42acab1c | 2124 | gimple *stmt = SSA_NAME_DEF_STMT (reaching_def); |
1a91d914 | 2125 | gphi *other_phi = dyn_cast <gphi *> (stmt); |
e60062ea | 2126 | |
2127 | /* Single element PHI nodes behave like copies, so get the | |
2128 | location from the phi argument. */ | |
1a91d914 | 2129 | if (other_phi |
2130 | && gimple_phi_num_args (other_phi) == 1) | |
2131 | locus = gimple_phi_arg_location (other_phi, 0); | |
e60062ea | 2132 | else |
2133 | locus = gimple_location (stmt); | |
2134 | } | |
efbcb6de | 2135 | |
2136 | gimple_phi_arg_set_location (phi, arg_i, locus); | |
88dbf20f | 2137 | } |
2138 | ||
efbcb6de | 2139 | |
88dbf20f | 2140 | if (e->flags & EDGE_ABNORMAL) |
2141 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (USE_FROM_PTR (arg_p)) = 1; | |
2142 | } | |
2143 | } | |
2144 | } | |
2145 | ||
54c91640 | 2146 | class rewrite_update_dom_walker : public dom_walker |
2147 | { | |
2148 | public: | |
11b3ff74 | 2149 | rewrite_update_dom_walker (cdi_direction direction) |
2150 | : dom_walker (direction, ALL_BLOCKS, NULL) {} | |
54c91640 | 2151 | |
96752458 | 2152 | virtual edge before_dom_children (basic_block); |
54c91640 | 2153 | virtual void after_dom_children (basic_block); |
2154 | }; | |
88dbf20f | 2155 | |
6bf320fb | 2156 | /* Initialization of block data structures for the incremental SSA |
2157 | update pass. Create a block local stack of reaching definitions | |
2158 | for new SSA names produced in this block (BLOCK_DEFS). Register | |
2159 | new definitions for every PHI node in the block. */ | |
2160 | ||
96752458 | 2161 | edge |
54c91640 | 2162 | rewrite_update_dom_walker::before_dom_children (basic_block bb) |
6bf320fb | 2163 | { |
6bf320fb | 2164 | bool is_abnormal_phi; |
6bf320fb | 2165 | |
2166 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
0ffbb1b6 | 2167 | fprintf (dump_file, "Registering new PHI nodes in block #%d\n", |
6bf320fb | 2168 | bb->index); |
2169 | ||
2170 | /* Mark the unwind point for this block. */ | |
f1f41a6c | 2171 | block_defs_stack.safe_push (NULL_TREE); |
6bf320fb | 2172 | |
2173 | if (!bitmap_bit_p (blocks_to_update, bb->index)) | |
96752458 | 2174 | return NULL; |
6bf320fb | 2175 | |
2176 | /* Mark the LHS if any of the arguments flows through an abnormal | |
2177 | edge. */ | |
f1047120 | 2178 | is_abnormal_phi = bb_has_abnormal_pred (bb); |
6bf320fb | 2179 | |
2180 | /* If any of the PHI nodes is a replacement for a name in | |
2181 | OLD_SSA_NAMES or it's one of the names in NEW_SSA_NAMES, then | |
2182 | register it as a new definition for its corresponding name. Also | |
2183 | register definitions for names whose underlying symbols are | |
2184 | marked for renaming. */ | |
1a91d914 | 2185 | for (gphi_iterator gsi = gsi_start_phis (bb); !gsi_end_p (gsi); |
2186 | gsi_next (&gsi)) | |
6bf320fb | 2187 | { |
2188 | tree lhs, lhs_sym; | |
1a91d914 | 2189 | gphi *phi = gsi.phi (); |
6bf320fb | 2190 | |
2191 | if (!register_defs_p (phi)) | |
2192 | continue; | |
48e1416a | 2193 | |
6bf320fb | 2194 | lhs = gimple_phi_result (phi); |
2195 | lhs_sym = SSA_NAME_VAR (lhs); | |
2196 | ||
e70e8b13 | 2197 | if (marked_for_renaming (lhs_sym)) |
6bf320fb | 2198 | register_new_update_single (lhs, lhs_sym); |
2199 | else | |
2200 | { | |
2201 | ||
2202 | /* If LHS is a new name, register a new definition for all | |
2203 | the names replaced by LHS. */ | |
2204 | if (is_new_name (lhs)) | |
2205 | register_new_update_set (lhs, names_replaced_by (lhs)); | |
48e1416a | 2206 | |
6bf320fb | 2207 | /* If LHS is an OLD name, register it as a new definition |
2208 | for itself. */ | |
2209 | if (is_old_name (lhs)) | |
2210 | register_new_update_single (lhs, lhs); | |
2211 | } | |
2212 | ||
2213 | if (is_abnormal_phi) | |
2214 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs) = 1; | |
2215 | } | |
2216 | ||
2217 | /* Step 2. Rewrite every variable used in each statement in the block. */ | |
08b7917c | 2218 | if (bitmap_bit_p (interesting_blocks, bb->index)) |
cd610ee6 | 2219 | { |
88536563 | 2220 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
1a91d914 | 2221 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi); ) |
4d8d655b | 2222 | if (rewrite_update_stmt (gsi_stmt (gsi), gsi)) |
2223 | gsi_remove (&gsi, true); | |
2224 | else | |
2225 | gsi_next (&gsi); | |
cd610ee6 | 2226 | } |
6bf320fb | 2227 | |
2228 | /* Step 3. Update PHI nodes. */ | |
2229 | rewrite_update_phi_arguments (bb); | |
96752458 | 2230 | |
2231 | return NULL; | |
6bf320fb | 2232 | } |
2233 | ||
2234 | /* Called after visiting block BB. Unwind BLOCK_DEFS_STACK to restore | |
2235 | the current reaching definition of every name re-written in BB to | |
2236 | the original reaching definition before visiting BB. This | |
2237 | unwinding must be done in the opposite order to what is done in | |
2238 | register_new_update_set. */ | |
2239 | ||
54c91640 | 2240 | void |
2241 | rewrite_update_dom_walker::after_dom_children (basic_block bb ATTRIBUTE_UNUSED) | |
6bf320fb | 2242 | { |
f1f41a6c | 2243 | while (block_defs_stack.length () > 0) |
6bf320fb | 2244 | { |
f1f41a6c | 2245 | tree var = block_defs_stack.pop (); |
6bf320fb | 2246 | tree saved_def; |
48e1416a | 2247 | |
6bf320fb | 2248 | /* NULL indicates the unwind stop point for this block (see |
2249 | rewrite_update_enter_block). */ | |
2250 | if (var == NULL) | |
2251 | return; | |
2252 | ||
f1f41a6c | 2253 | saved_def = block_defs_stack.pop (); |
74105c0d | 2254 | get_common_info (var)->current_def = saved_def; |
6bf320fb | 2255 | } |
2256 | } | |
2257 | ||
2258 | ||
88dbf20f | 2259 | /* Rewrite the actual blocks, statements, and PHI arguments, to be in SSA |
48e1416a | 2260 | form. |
88dbf20f | 2261 | |
2262 | ENTRY indicates the block where to start. Every block dominated by | |
2263 | ENTRY will be rewritten. | |
2264 | ||
2265 | WHAT indicates what actions will be taken by the renamer (see enum | |
2266 | rewrite_mode). | |
2267 | ||
2268 | BLOCKS are the set of interesting blocks for the dominator walker | |
2269 | to process. If this set is NULL, then all the nodes dominated | |
2270 | by ENTRY are walked. Otherwise, blocks dominated by ENTRY that | |
2271 | are not present in BLOCKS are ignored. */ | |
2272 | ||
2273 | static void | |
6bf320fb | 2274 | rewrite_blocks (basic_block entry, enum rewrite_mode what) |
88dbf20f | 2275 | { |
88dbf20f | 2276 | /* Rewrite all the basic blocks in the program. */ |
2277 | timevar_push (TV_TREE_SSA_REWRITE_BLOCKS); | |
2278 | ||
54c91640 | 2279 | block_defs_stack.create (10); |
88dbf20f | 2280 | |
54c91640 | 2281 | /* Recursively walk the dominator tree rewriting each statement in |
2282 | each basic block. */ | |
88dbf20f | 2283 | if (what == REWRITE_ALL) |
54c91640 | 2284 | rewrite_dom_walker (CDI_DOMINATORS).walk (entry); |
88dbf20f | 2285 | else if (what == REWRITE_UPDATE) |
54c91640 | 2286 | rewrite_update_dom_walker (CDI_DOMINATORS).walk (entry); |
88dbf20f | 2287 | else |
2288 | gcc_unreachable (); | |
2289 | ||
88dbf20f | 2290 | /* Debugging dumps. */ |
2291 | if (dump_file && (dump_flags & TDF_STATS)) | |
2292 | { | |
2293 | dump_dfa_stats (dump_file); | |
c1f445d2 | 2294 | if (var_infos) |
88dbf20f | 2295 | dump_tree_ssa_stats (dump_file); |
2296 | } | |
48e1416a | 2297 | |
f1f41a6c | 2298 | block_defs_stack.release (); |
88dbf20f | 2299 | |
2300 | timevar_pop (TV_TREE_SSA_REWRITE_BLOCKS); | |
2301 | } | |
2302 | ||
54c91640 | 2303 | class mark_def_dom_walker : public dom_walker |
e551bd1a | 2304 | { |
54c91640 | 2305 | public: |
2306 | mark_def_dom_walker (cdi_direction direction); | |
2307 | ~mark_def_dom_walker (); | |
f3d9a16c | 2308 | |
96752458 | 2309 | virtual edge before_dom_children (basic_block); |
f3d9a16c | 2310 | |
54c91640 | 2311 | private: |
e551bd1a | 2312 | /* Notice that this bitmap is indexed using variable UIDs, so it must be |
2313 | large enough to accommodate all the variables referenced in the | |
2314 | function, not just the ones we are renaming. */ | |
ae84f584 | 2315 | bitmap m_kills; |
54c91640 | 2316 | }; |
4ee9c684 | 2317 | |
54c91640 | 2318 | mark_def_dom_walker::mark_def_dom_walker (cdi_direction direction) |
11b3ff74 | 2319 | : dom_walker (direction, ALL_BLOCKS, NULL), m_kills (BITMAP_ALLOC (NULL)) |
54c91640 | 2320 | { |
2321 | } | |
e551bd1a | 2322 | |
54c91640 | 2323 | mark_def_dom_walker::~mark_def_dom_walker () |
2324 | { | |
ae84f584 | 2325 | BITMAP_FREE (m_kills); |
54c91640 | 2326 | } |
e551bd1a | 2327 | |
54c91640 | 2328 | /* Block processing routine for mark_def_sites. Clear the KILLS bitmap |
2329 | at the start of each block, and call mark_def_sites for each statement. */ | |
e551bd1a | 2330 | |
96752458 | 2331 | edge |
54c91640 | 2332 | mark_def_dom_walker::before_dom_children (basic_block bb) |
2333 | { | |
2334 | gimple_stmt_iterator gsi; | |
e551bd1a | 2335 | |
ae84f584 | 2336 | bitmap_clear (m_kills); |
54c91640 | 2337 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
ae84f584 | 2338 | mark_def_sites (bb, gsi_stmt (gsi), m_kills); |
96752458 | 2339 | return NULL; |
4ee9c684 | 2340 | } |
2341 | ||
4fb5e5ca | 2342 | /* Initialize internal data needed during renaming. */ |
2343 | ||
2344 | static void | |
2345 | init_ssa_renamer (void) | |
2346 | { | |
4fb5e5ca | 2347 | cfun->gimple_df->in_ssa_p = false; |
2348 | ||
2349 | /* Allocate memory for the DEF_BLOCKS hash table. */ | |
c1f445d2 | 2350 | gcc_assert (!var_infos); |
2351 | var_infos = new hash_table<var_info_hasher> | |
2352 | (vec_safe_length (cfun->local_decls)); | |
4fb5e5ca | 2353 | |
22d6c74e | 2354 | bitmap_obstack_initialize (&update_ssa_obstack); |
4fb5e5ca | 2355 | } |
2356 | ||
2357 | ||
2358 | /* Deallocate internal data structures used by the renamer. */ | |
2359 | ||
2360 | static void | |
2361 | fini_ssa_renamer (void) | |
2362 | { | |
c1f445d2 | 2363 | delete var_infos; |
2364 | var_infos = NULL; | |
4fb5e5ca | 2365 | |
22d6c74e | 2366 | bitmap_obstack_release (&update_ssa_obstack); |
2367 | ||
e70e8b13 | 2368 | cfun->gimple_df->ssa_renaming_needed = 0; |
2369 | cfun->gimple_df->rename_vops = 0; | |
4fb5e5ca | 2370 | cfun->gimple_df->in_ssa_p = true; |
2371 | } | |
2372 | ||
e551bd1a | 2373 | /* Main entry point into the SSA builder. The renaming process |
88dbf20f | 2374 | proceeds in four main phases: |
4ee9c684 | 2375 | |
88dbf20f | 2376 | 1- Compute dominance frontier and immediate dominators, needed to |
2377 | insert PHI nodes and rename the function in dominator tree | |
2378 | order. | |
4ee9c684 | 2379 | |
54c91640 | 2380 | 2- Find and mark all the blocks that define variables. |
4ee9c684 | 2381 | |
88dbf20f | 2382 | 3- Insert PHI nodes at dominance frontiers (insert_phi_nodes). |
4ee9c684 | 2383 | |
88dbf20f | 2384 | 4- Rename all the blocks (rewrite_blocks) and statements in the program. |
4ee9c684 | 2385 | |
21bdfe89 | 2386 | Steps 3 and 4 are done using the dominator tree walker |
88dbf20f | 2387 | (walk_dominator_tree). */ |
e551bd1a | 2388 | |
65b0537f | 2389 | namespace { |
2390 | ||
2391 | const pass_data pass_data_build_ssa = | |
2392 | { | |
2393 | GIMPLE_PASS, /* type */ | |
2394 | "ssa", /* name */ | |
2395 | OPTGROUP_NONE, /* optinfo_flags */ | |
65b0537f | 2396 | TV_TREE_SSA_OTHER, /* tv_id */ |
2397 | PROP_cfg, /* properties_required */ | |
2398 | PROP_ssa, /* properties_provided */ | |
2399 | 0, /* properties_destroyed */ | |
2400 | 0, /* todo_flags_start */ | |
8b88439e | 2401 | TODO_remove_unused_locals, /* todo_flags_finish */ |
65b0537f | 2402 | }; |
2403 | ||
2404 | class pass_build_ssa : public gimple_opt_pass | |
2405 | { | |
2406 | public: | |
2407 | pass_build_ssa (gcc::context *ctxt) | |
2408 | : gimple_opt_pass (pass_data_build_ssa, ctxt) | |
2409 | {} | |
2410 | ||
2411 | /* opt_pass methods: */ | |
2412 | virtual bool gate (function *fun) | |
2413 | { | |
2414 | /* Do nothing for funcions that was produced already in SSA form. */ | |
2415 | return !(fun->curr_properties & PROP_ssa); | |
2416 | } | |
2417 | ||
2418 | virtual unsigned int execute (function *); | |
2419 | ||
2420 | }; // class pass_build_ssa | |
2421 | ||
2422 | unsigned int | |
2423 | pass_build_ssa::execute (function *fun) | |
4ee9c684 | 2424 | { |
8a2980be | 2425 | bitmap_head *dfs; |
e551bd1a | 2426 | basic_block bb; |
48e1416a | 2427 | |
88dbf20f | 2428 | /* Initialize operand data structures. */ |
65b0537f | 2429 | init_ssa_operands (fun); |
4ee9c684 | 2430 | |
4fb5e5ca | 2431 | /* Initialize internal data needed by the renamer. */ |
2432 | init_ssa_renamer (); | |
2433 | ||
88dbf20f | 2434 | /* Initialize the set of interesting blocks. The callback |
2435 | mark_def_sites will add to this set those blocks that the renamer | |
2436 | should process. */ | |
65b0537f | 2437 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (fun)); |
53c5d9d4 | 2438 | bitmap_clear (interesting_blocks); |
4ee9c684 | 2439 | |
71797bf6 | 2440 | /* Initialize dominance frontier. */ |
65b0537f | 2441 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (fun)); |
2442 | FOR_EACH_BB_FN (bb, fun) | |
8a2980be | 2443 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
4ee9c684 | 2444 | |
88dbf20f | 2445 | /* 1- Compute dominance frontiers. */ |
2446 | calculate_dominance_info (CDI_DOMINATORS); | |
e551bd1a | 2447 | compute_dominance_frontiers (dfs); |
4ee9c684 | 2448 | |
88dbf20f | 2449 | /* 2- Find and mark definition sites. */ |
65b0537f | 2450 | mark_def_dom_walker (CDI_DOMINATORS).walk (fun->cfg->x_entry_block_ptr); |
88dbf20f | 2451 | |
2452 | /* 3- Insert PHI nodes at dominance frontiers of definition blocks. */ | |
095dcfa3 | 2453 | insert_phi_nodes (dfs); |
4ee9c684 | 2454 | |
88dbf20f | 2455 | /* 4- Rename all the blocks. */ |
65b0537f | 2456 | rewrite_blocks (ENTRY_BLOCK_PTR_FOR_FN (fun), REWRITE_ALL); |
4ee9c684 | 2457 | |
e551bd1a | 2458 | /* Free allocated memory. */ |
65b0537f | 2459 | FOR_EACH_BB_FN (bb, fun) |
8a2980be | 2460 | bitmap_clear (&dfs[bb->index]); |
e551bd1a | 2461 | free (dfs); |
4ee9c684 | 2462 | |
acf11b62 | 2463 | sbitmap_free (interesting_blocks); |
2464 | ||
4fb5e5ca | 2465 | fini_ssa_renamer (); |
2466 | ||
ec11736b | 2467 | /* Try to get rid of all gimplifier generated temporaries by making |
2468 | its SSA names anonymous. This way we can garbage collect them | |
2469 | all after removing unused locals which we do in our TODO. */ | |
f211616e | 2470 | unsigned i; |
2471 | tree name; | |
2472 | ||
2473 | FOR_EACH_SSA_NAME (i, name, cfun) | |
ec11736b | 2474 | { |
f211616e | 2475 | if (SSA_NAME_IS_DEFAULT_DEF (name)) |
ec11736b | 2476 | continue; |
f211616e | 2477 | tree decl = SSA_NAME_VAR (name); |
ec11736b | 2478 | if (decl |
53e9c5c4 | 2479 | && VAR_P (decl) |
ec11736b | 2480 | && !VAR_DECL_IS_VIRTUAL_OPERAND (decl) |
382c2352 | 2481 | && DECL_IGNORED_P (decl)) |
2482 | SET_SSA_NAME_VAR_OR_IDENTIFIER (name, DECL_NAME (decl)); | |
ec11736b | 2483 | } |
2484 | ||
5477dab8 | 2485 | /* Initialize SSA_NAME_POINTS_TO_READONLY_MEMORY. */ |
2486 | tree fnspec = lookup_attribute ("fn spec", | |
2487 | TYPE_ATTRIBUTES (TREE_TYPE (fun->decl))); | |
2488 | if (fnspec) | |
2489 | { | |
2490 | fnspec = TREE_VALUE (TREE_VALUE (fnspec)); | |
2491 | unsigned i = 1; | |
2492 | for (tree arg = DECL_ARGUMENTS (cfun->decl); | |
2493 | arg; arg = DECL_CHAIN (arg), ++i) | |
2494 | { | |
2495 | if (i >= (unsigned) TREE_STRING_LENGTH (fnspec)) | |
2496 | break; | |
2497 | if (TREE_STRING_POINTER (fnspec)[i] == 'R' | |
2498 | || TREE_STRING_POINTER (fnspec)[i] == 'r') | |
2499 | { | |
2500 | tree name = ssa_default_def (fun, arg); | |
2501 | if (name) | |
2502 | SSA_NAME_POINTS_TO_READONLY_MEMORY (name) = 1; | |
2503 | } | |
2504 | } | |
2505 | } | |
2506 | ||
2a1990e9 | 2507 | return 0; |
4ee9c684 | 2508 | } |
2509 | ||
cbe8bda8 | 2510 | } // anon namespace |
2511 | ||
2512 | gimple_opt_pass * | |
2513 | make_pass_build_ssa (gcc::context *ctxt) | |
2514 | { | |
2515 | return new pass_build_ssa (ctxt); | |
2516 | } | |
2517 | ||
4ee9c684 | 2518 | |
88dbf20f | 2519 | /* Mark the definition of VAR at STMT and BB as interesting for the |
2520 | renamer. BLOCKS is the set of blocks that need updating. */ | |
4ee9c684 | 2521 | |
88dbf20f | 2522 | static void |
42acab1c | 2523 | mark_def_interesting (tree var, gimple *stmt, basic_block bb, |
2524 | bool insert_phi_p) | |
4ee9c684 | 2525 | { |
88536563 | 2526 | gcc_checking_assert (bitmap_bit_p (blocks_to_update, bb->index)); |
75a70cf9 | 2527 | set_register_defs (stmt, true); |
88dbf20f | 2528 | |
2529 | if (insert_phi_p) | |
2530 | { | |
75a70cf9 | 2531 | bool is_phi_p = gimple_code (stmt) == GIMPLE_PHI; |
88dbf20f | 2532 | |
88dbf20f | 2533 | set_def_block (var, bb, is_phi_p); |
2534 | ||
2535 | /* If VAR is an SSA name in NEW_SSA_NAMES, this is a definition | |
2536 | site for both itself and all the old names replaced by it. */ | |
2537 | if (TREE_CODE (var) == SSA_NAME && is_new_name (var)) | |
2538 | { | |
2539 | bitmap_iterator bi; | |
2540 | unsigned i; | |
2541 | bitmap set = names_replaced_by (var); | |
2542 | if (set) | |
2543 | EXECUTE_IF_SET_IN_BITMAP (set, 0, i, bi) | |
2544 | set_def_block (ssa_name (i), bb, is_phi_p); | |
2545 | } | |
2546 | } | |
2547 | } | |
2548 | ||
2549 | ||
2550 | /* Mark the use of VAR at STMT and BB as interesting for the | |
2551 | renamer. INSERT_PHI_P is true if we are going to insert new PHI | |
2920559d | 2552 | nodes. */ |
88dbf20f | 2553 | |
2554 | static inline void | |
42acab1c | 2555 | mark_use_interesting (tree var, gimple *stmt, basic_block bb, |
2556 | bool insert_phi_p) | |
88dbf20f | 2557 | { |
75a70cf9 | 2558 | basic_block def_bb = gimple_bb (stmt); |
70630fcd | 2559 | |
2920559d | 2560 | mark_block_for_update (def_bb); |
2561 | mark_block_for_update (bb); | |
2562 | ||
75a70cf9 | 2563 | if (gimple_code (stmt) == GIMPLE_PHI) |
1a91d914 | 2564 | mark_phi_for_rewrite (def_bb, as_a <gphi *> (stmt)); |
70630fcd | 2565 | else |
9845d120 | 2566 | { |
2567 | set_rewrite_uses (stmt, true); | |
2568 | ||
2569 | if (is_gimple_debug (stmt)) | |
2570 | return; | |
2571 | } | |
88dbf20f | 2572 | |
2573 | /* If VAR has not been defined in BB, then it is live-on-entry | |
2574 | to BB. Note that we cannot just use the block holding VAR's | |
2575 | definition because if VAR is one of the names in OLD_SSA_NAMES, | |
2576 | it will have several definitions (itself and all the names that | |
2577 | replace it). */ | |
2578 | if (insert_phi_p) | |
2579 | { | |
04009ada | 2580 | def_blocks *db_p = get_def_blocks_for (get_common_info (var)); |
88dbf20f | 2581 | if (!bitmap_bit_p (db_p->def_blocks, bb->index)) |
2582 | set_livein_block (var, bb); | |
2583 | } | |
2584 | } | |
2585 | ||
2586 | ||
88dbf20f | 2587 | /* Do a dominator walk starting at BB processing statements that |
e70e8b13 | 2588 | reference symbols in SSA operands. This is very similar to |
095dcfa3 | 2589 | mark_def_sites, but the scan handles statements whose operands may |
2920559d | 2590 | already be SSA names. |
88dbf20f | 2591 | |
095dcfa3 | 2592 | If INSERT_PHI_P is true, mark those uses as live in the |
2593 | corresponding block. This is later used by the PHI placement | |
4fb5e5ca | 2594 | algorithm to make PHI pruning decisions. |
2595 | ||
2596 | FIXME. Most of this would be unnecessary if we could associate a | |
2597 | symbol to all the SSA names that reference it. But that | |
2598 | sounds like it would be expensive to maintain. Still, it | |
2599 | would be interesting to see if it makes better sense to do | |
2600 | that. */ | |
88dbf20f | 2601 | |
2602 | static void | |
2920559d | 2603 | prepare_block_for_update (basic_block bb, bool insert_phi_p) |
88dbf20f | 2604 | { |
2605 | basic_block son; | |
f50cf978 | 2606 | edge e; |
2607 | edge_iterator ei; | |
88dbf20f | 2608 | |
2920559d | 2609 | mark_block_for_update (bb); |
2610 | ||
88dbf20f | 2611 | /* Process PHI nodes marking interesting those that define or use |
095dcfa3 | 2612 | the symbols that we are interested in. */ |
1a91d914 | 2613 | for (gphi_iterator si = gsi_start_phis (bb); !gsi_end_p (si); |
2614 | gsi_next (&si)) | |
88dbf20f | 2615 | { |
1a91d914 | 2616 | gphi *phi = si.phi (); |
75a70cf9 | 2617 | tree lhs_sym, lhs = gimple_phi_result (phi); |
88dbf20f | 2618 | |
e70e8b13 | 2619 | if (TREE_CODE (lhs) == SSA_NAME |
0087edc6 | 2620 | && (! virtual_operand_p (lhs) |
2621 | || ! cfun->gimple_df->rename_vops)) | |
f50cf978 | 2622 | continue; |
75a70cf9 | 2623 | |
0087edc6 | 2624 | lhs_sym = DECL_P (lhs) ? lhs : SSA_NAME_VAR (lhs); |
e70e8b13 | 2625 | mark_for_renaming (lhs_sym); |
f50cf978 | 2626 | mark_def_interesting (lhs_sym, phi, bb, insert_phi_p); |
2627 | ||
2628 | /* Mark the uses in phi nodes as interesting. It would be more correct | |
2629 | to process the arguments of the phi nodes of the successor edges of | |
2630 | BB at the end of prepare_block_for_update, however, that turns out | |
2631 | to be significantly more expensive. Doing it here is conservatively | |
2632 | correct -- it may only cause us to believe a value to be live in a | |
2633 | block that also contains its definition, and thus insert a few more | |
2634 | phi nodes for it. */ | |
2635 | FOR_EACH_EDGE (e, ei, bb->preds) | |
75a70cf9 | 2636 | mark_use_interesting (lhs_sym, phi, e->src, insert_phi_p); |
88dbf20f | 2637 | } |
2638 | ||
2639 | /* Process the statements. */ | |
1a91d914 | 2640 | for (gimple_stmt_iterator si = gsi_start_bb (bb); !gsi_end_p (si); |
2641 | gsi_next (&si)) | |
88dbf20f | 2642 | { |
42acab1c | 2643 | gimple *stmt; |
88dbf20f | 2644 | ssa_op_iter i; |
2645 | use_operand_p use_p; | |
2646 | def_operand_p def_p; | |
48e1416a | 2647 | |
75a70cf9 | 2648 | stmt = gsi_stmt (si); |
88dbf20f | 2649 | |
e70e8b13 | 2650 | if (cfun->gimple_df->rename_vops |
2651 | && gimple_vuse (stmt)) | |
88dbf20f | 2652 | { |
e70e8b13 | 2653 | tree use = gimple_vuse (stmt); |
88dbf20f | 2654 | tree sym = DECL_P (use) ? use : SSA_NAME_VAR (use); |
e70e8b13 | 2655 | mark_for_renaming (sym); |
2656 | mark_use_interesting (sym, stmt, bb, insert_phi_p); | |
88dbf20f | 2657 | } |
2658 | ||
e70e8b13 | 2659 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_USE) |
88dbf20f | 2660 | { |
e70e8b13 | 2661 | tree use = USE_FROM_PTR (use_p); |
2662 | if (!DECL_P (use)) | |
2663 | continue; | |
2664 | mark_for_renaming (use); | |
2665 | mark_use_interesting (use, stmt, bb, insert_phi_p); | |
2666 | } | |
2667 | ||
2668 | if (cfun->gimple_df->rename_vops | |
2669 | && gimple_vdef (stmt)) | |
2670 | { | |
2671 | tree def = gimple_vdef (stmt); | |
88dbf20f | 2672 | tree sym = DECL_P (def) ? def : SSA_NAME_VAR (def); |
e70e8b13 | 2673 | mark_for_renaming (sym); |
2674 | mark_def_interesting (sym, stmt, bb, insert_phi_p); | |
2675 | } | |
2676 | ||
2677 | FOR_EACH_SSA_DEF_OPERAND (def_p, stmt, i, SSA_OP_DEF) | |
2678 | { | |
2679 | tree def = DEF_FROM_PTR (def_p); | |
2680 | if (!DECL_P (def)) | |
2681 | continue; | |
2682 | mark_for_renaming (def); | |
2683 | mark_def_interesting (def, stmt, bb, insert_phi_p); | |
88dbf20f | 2684 | } |
2685 | } | |
2686 | ||
2687 | /* Now visit all the blocks dominated by BB. */ | |
095dcfa3 | 2688 | for (son = first_dom_son (CDI_DOMINATORS, bb); |
4fb5e5ca | 2689 | son; |
2690 | son = next_dom_son (CDI_DOMINATORS, son)) | |
2920559d | 2691 | prepare_block_for_update (son, insert_phi_p); |
095dcfa3 | 2692 | } |
2693 | ||
2694 | ||
2695 | /* Helper for prepare_names_to_update. Mark all the use sites for | |
2696 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2697 | prepare_names_to_update. */ | |
2698 | ||
2699 | static void | |
2920559d | 2700 | prepare_use_sites_for (tree name, bool insert_phi_p) |
095dcfa3 | 2701 | { |
2702 | use_operand_p use_p; | |
2703 | imm_use_iterator iter; | |
2704 | ||
fcc0ec6b | 2705 | /* If we rename virtual operands do not update them. */ |
2706 | if (virtual_operand_p (name) | |
2707 | && cfun->gimple_df->rename_vops) | |
2708 | return; | |
2709 | ||
095dcfa3 | 2710 | FOR_EACH_IMM_USE_FAST (use_p, iter, name) |
2711 | { | |
42acab1c | 2712 | gimple *stmt = USE_STMT (use_p); |
75a70cf9 | 2713 | basic_block bb = gimple_bb (stmt); |
095dcfa3 | 2714 | |
75a70cf9 | 2715 | if (gimple_code (stmt) == GIMPLE_PHI) |
095dcfa3 | 2716 | { |
f50cf978 | 2717 | int ix = PHI_ARG_INDEX_FROM_USE (use_p); |
1a91d914 | 2718 | edge e = gimple_phi_arg_edge (as_a <gphi *> (stmt), ix); |
f50cf978 | 2719 | mark_use_interesting (name, stmt, e->src, insert_phi_p); |
095dcfa3 | 2720 | } |
2721 | else | |
2722 | { | |
2723 | /* For regular statements, mark this as an interesting use | |
2724 | for NAME. */ | |
2920559d | 2725 | mark_use_interesting (name, stmt, bb, insert_phi_p); |
095dcfa3 | 2726 | } |
2727 | } | |
88dbf20f | 2728 | } |
2729 | ||
2730 | ||
095dcfa3 | 2731 | /* Helper for prepare_names_to_update. Mark the definition site for |
2732 | NAME as interesting. BLOCKS and INSERT_PHI_P are as in | |
2733 | prepare_names_to_update. */ | |
88dbf20f | 2734 | |
2735 | static void | |
2920559d | 2736 | prepare_def_site_for (tree name, bool insert_phi_p) |
88dbf20f | 2737 | { |
42acab1c | 2738 | gimple *stmt; |
88dbf20f | 2739 | basic_block bb; |
2740 | ||
88536563 | 2741 | gcc_checking_assert (names_to_release == NULL |
2742 | || !bitmap_bit_p (names_to_release, | |
2743 | SSA_NAME_VERSION (name))); | |
88dbf20f | 2744 | |
fcc0ec6b | 2745 | /* If we rename virtual operands do not update them. */ |
2746 | if (virtual_operand_p (name) | |
2747 | && cfun->gimple_df->rename_vops) | |
2748 | return; | |
2749 | ||
88dbf20f | 2750 | stmt = SSA_NAME_DEF_STMT (name); |
75a70cf9 | 2751 | bb = gimple_bb (stmt); |
88dbf20f | 2752 | if (bb) |
2753 | { | |
fe672ac0 | 2754 | gcc_checking_assert (bb->index < last_basic_block_for_fn (cfun)); |
2920559d | 2755 | mark_block_for_update (bb); |
2756 | mark_def_interesting (name, stmt, bb, insert_phi_p); | |
88dbf20f | 2757 | } |
2758 | } | |
2759 | ||
2760 | ||
095dcfa3 | 2761 | /* Mark definition and use sites of names in NEW_SSA_NAMES and |
2920559d | 2762 | OLD_SSA_NAMES. INSERT_PHI_P is true if the caller wants to insert |
2763 | PHI nodes for newly created names. */ | |
88dbf20f | 2764 | |
2765 | static void | |
2920559d | 2766 | prepare_names_to_update (bool insert_phi_p) |
88dbf20f | 2767 | { |
86c1585a | 2768 | unsigned i = 0; |
88dbf20f | 2769 | bitmap_iterator bi; |
3e790786 | 2770 | sbitmap_iterator sbi; |
88dbf20f | 2771 | |
2772 | /* If a name N from NEW_SSA_NAMES is also marked to be released, | |
2773 | remove it from NEW_SSA_NAMES so that we don't try to visit its | |
2774 | defining basic block (which most likely doesn't exist). Notice | |
2775 | that we cannot do the same with names in OLD_SSA_NAMES because we | |
2776 | want to replace existing instances. */ | |
2777 | if (names_to_release) | |
2778 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
08b7917c | 2779 | bitmap_clear_bit (new_ssa_names, i); |
88dbf20f | 2780 | |
095dcfa3 | 2781 | /* First process names in NEW_SSA_NAMES. Otherwise, uses of old |
2782 | names may be considered to be live-in on blocks that contain | |
2783 | definitions for their replacements. */ | |
0d211963 | 2784 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
2920559d | 2785 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
095dcfa3 | 2786 | |
88dbf20f | 2787 | /* If an old name is in NAMES_TO_RELEASE, we cannot remove it from |
2788 | OLD_SSA_NAMES, but we have to ignore its definition site. */ | |
0d211963 | 2789 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
095dcfa3 | 2790 | { |
2791 | if (names_to_release == NULL || !bitmap_bit_p (names_to_release, i)) | |
2920559d | 2792 | prepare_def_site_for (ssa_name (i), insert_phi_p); |
2793 | prepare_use_sites_for (ssa_name (i), insert_phi_p); | |
3e790786 | 2794 | } |
88dbf20f | 2795 | } |
2796 | ||
2797 | ||
2798 | /* Dump all the names replaced by NAME to FILE. */ | |
2799 | ||
2800 | void | |
2801 | dump_names_replaced_by (FILE *file, tree name) | |
2802 | { | |
2803 | unsigned i; | |
2804 | bitmap old_set; | |
2805 | bitmap_iterator bi; | |
2806 | ||
1ffa4346 | 2807 | print_generic_expr (file, name); |
88dbf20f | 2808 | fprintf (file, " -> { "); |
2809 | ||
2810 | old_set = names_replaced_by (name); | |
2811 | EXECUTE_IF_SET_IN_BITMAP (old_set, 0, i, bi) | |
2812 | { | |
1ffa4346 | 2813 | print_generic_expr (file, ssa_name (i)); |
88dbf20f | 2814 | fprintf (file, " "); |
2815 | } | |
2816 | ||
2817 | fprintf (file, "}\n"); | |
2818 | } | |
2819 | ||
2820 | ||
2821 | /* Dump all the names replaced by NAME to stderr. */ | |
2822 | ||
4b987fac | 2823 | DEBUG_FUNCTION void |
88dbf20f | 2824 | debug_names_replaced_by (tree name) |
2825 | { | |
2826 | dump_names_replaced_by (stderr, name); | |
2827 | } | |
2828 | ||
2829 | ||
095dcfa3 | 2830 | /* Dump SSA update information to FILE. */ |
88dbf20f | 2831 | |
2832 | void | |
095dcfa3 | 2833 | dump_update_ssa (FILE *file) |
88dbf20f | 2834 | { |
86c1585a | 2835 | unsigned i = 0; |
88dbf20f | 2836 | bitmap_iterator bi; |
2837 | ||
dd277d48 | 2838 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 2839 | return; |
2840 | ||
53c5d9d4 | 2841 | if (new_ssa_names && bitmap_first_set_bit (new_ssa_names) >= 0) |
88dbf20f | 2842 | { |
3e790786 | 2843 | sbitmap_iterator sbi; |
2844 | ||
88dbf20f | 2845 | fprintf (file, "\nSSA replacement table\n"); |
2846 | fprintf (file, "N_i -> { O_1 ... O_j } means that N_i replaces " | |
2847 | "O_1, ..., O_j\n\n"); | |
2848 | ||
0d211963 | 2849 | EXECUTE_IF_SET_IN_BITMAP (new_ssa_names, 0, i, sbi) |
3e790786 | 2850 | dump_names_replaced_by (file, ssa_name (i)); |
88dbf20f | 2851 | } |
2852 | ||
e70e8b13 | 2853 | if (symbols_to_rename_set && !bitmap_empty_p (symbols_to_rename_set)) |
88dbf20f | 2854 | { |
0ffbb1b6 | 2855 | fprintf (file, "\nSymbols to be put in SSA form\n"); |
e70e8b13 | 2856 | dump_decl_set (file, symbols_to_rename_set); |
dd277d48 | 2857 | fprintf (file, "\n"); |
88dbf20f | 2858 | } |
2859 | ||
88dbf20f | 2860 | if (names_to_release && !bitmap_empty_p (names_to_release)) |
2861 | { | |
0ffbb1b6 | 2862 | fprintf (file, "\nSSA names to release after updating the SSA web\n\n"); |
88dbf20f | 2863 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) |
2864 | { | |
1ffa4346 | 2865 | print_generic_expr (file, ssa_name (i)); |
88dbf20f | 2866 | fprintf (file, " "); |
2867 | } | |
0ffbb1b6 | 2868 | fprintf (file, "\n"); |
88dbf20f | 2869 | } |
88dbf20f | 2870 | } |
2871 | ||
2872 | ||
095dcfa3 | 2873 | /* Dump SSA update information to stderr. */ |
88dbf20f | 2874 | |
4b987fac | 2875 | DEBUG_FUNCTION void |
095dcfa3 | 2876 | debug_update_ssa (void) |
88dbf20f | 2877 | { |
095dcfa3 | 2878 | dump_update_ssa (stderr); |
88dbf20f | 2879 | } |
2880 | ||
2881 | ||
2882 | /* Initialize data structures used for incremental SSA updates. */ | |
2883 | ||
2884 | static void | |
dd277d48 | 2885 | init_update_ssa (struct function *fn) |
88dbf20f | 2886 | { |
095dcfa3 | 2887 | /* Reserve more space than the current number of names. The calls to |
88dbf20f | 2888 | add_new_name_mapping are typically done after creating new SSA |
2889 | names, so we'll need to reallocate these arrays. */ | |
2890 | old_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
53c5d9d4 | 2891 | bitmap_clear (old_ssa_names); |
88dbf20f | 2892 | |
2893 | new_ssa_names = sbitmap_alloc (num_ssa_names + NAME_SETS_GROWTH_FACTOR); | |
53c5d9d4 | 2894 | bitmap_clear (new_ssa_names); |
88dbf20f | 2895 | |
5eeafc2d | 2896 | bitmap_obstack_initialize (&update_ssa_obstack); |
2897 | ||
88dbf20f | 2898 | names_to_release = NULL; |
dd277d48 | 2899 | update_ssa_initialized_fn = fn; |
88dbf20f | 2900 | } |
2901 | ||
2902 | ||
2903 | /* Deallocate data structures used for incremental SSA updates. */ | |
2904 | ||
095dcfa3 | 2905 | void |
88dbf20f | 2906 | delete_update_ssa (void) |
2907 | { | |
2908 | unsigned i; | |
2909 | bitmap_iterator bi; | |
2910 | ||
2911 | sbitmap_free (old_ssa_names); | |
2912 | old_ssa_names = NULL; | |
2913 | ||
2914 | sbitmap_free (new_ssa_names); | |
2915 | new_ssa_names = NULL; | |
2916 | ||
e70e8b13 | 2917 | BITMAP_FREE (symbols_to_rename_set); |
2918 | symbols_to_rename_set = NULL; | |
f1f41a6c | 2919 | symbols_to_rename.release (); |
88dbf20f | 2920 | |
2921 | if (names_to_release) | |
2922 | { | |
2923 | EXECUTE_IF_SET_IN_BITMAP (names_to_release, 0, i, bi) | |
2924 | release_ssa_name (ssa_name (i)); | |
2925 | BITMAP_FREE (names_to_release); | |
2926 | } | |
2927 | ||
2920559d | 2928 | clear_ssa_name_info (); |
4fb5e5ca | 2929 | |
2930 | fini_ssa_renamer (); | |
2931 | ||
2932 | if (blocks_with_phis_to_rewrite) | |
2933 | EXECUTE_IF_SET_IN_BITMAP (blocks_with_phis_to_rewrite, 0, i, bi) | |
2934 | { | |
1a91d914 | 2935 | vec<gphi *> phis = phis_to_rewrite[i]; |
f1f41a6c | 2936 | phis.release (); |
2937 | phis_to_rewrite[i].create (0); | |
4fb5e5ca | 2938 | } |
2939 | ||
2940 | BITMAP_FREE (blocks_with_phis_to_rewrite); | |
2941 | BITMAP_FREE (blocks_to_update); | |
5eeafc2d | 2942 | |
dd277d48 | 2943 | update_ssa_initialized_fn = NULL; |
88dbf20f | 2944 | } |
2945 | ||
2946 | ||
2947 | /* Create a new name for OLD_NAME in statement STMT and replace the | |
0dc262e0 | 2948 | operand pointed to by DEF_P with the newly created name. If DEF_P |
2949 | is NULL then STMT should be a GIMPLE assignment. | |
2950 | Return the new name and register the replacement mapping <NEW, OLD> in | |
88dbf20f | 2951 | update_ssa's tables. */ |
2952 | ||
2953 | tree | |
42acab1c | 2954 | create_new_def_for (tree old_name, gimple *stmt, def_operand_p def) |
88dbf20f | 2955 | { |
0dc262e0 | 2956 | tree new_name; |
88dbf20f | 2957 | |
0dc262e0 | 2958 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
2959 | ||
2960 | if (!update_ssa_initialized_fn) | |
2961 | init_update_ssa (cfun); | |
2962 | ||
2963 | gcc_assert (update_ssa_initialized_fn == cfun); | |
2964 | ||
2965 | new_name = duplicate_ssa_name (old_name, stmt); | |
2966 | if (def) | |
2967 | SET_DEF (def, new_name); | |
2968 | else | |
2969 | gimple_assign_set_lhs (stmt, new_name); | |
88dbf20f | 2970 | |
75a70cf9 | 2971 | if (gimple_code (stmt) == GIMPLE_PHI) |
88dbf20f | 2972 | { |
75a70cf9 | 2973 | basic_block bb = gimple_bb (stmt); |
88dbf20f | 2974 | |
2975 | /* If needed, mark NEW_NAME as occurring in an abnormal PHI node. */ | |
f1047120 | 2976 | SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_name) = bb_has_abnormal_pred (bb); |
88dbf20f | 2977 | } |
2978 | ||
0dc262e0 | 2979 | add_new_name_mapping (new_name, old_name); |
88dbf20f | 2980 | |
2981 | /* For the benefit of passes that will be updating the SSA form on | |
2982 | their own, set the current reaching definition of OLD_NAME to be | |
2983 | NEW_NAME. */ | |
74105c0d | 2984 | get_ssa_name_ann (old_name)->info.current_def = new_name; |
88dbf20f | 2985 | |
0dc262e0 | 2986 | timevar_pop (TV_TREE_SSA_INCREMENTAL); |
88dbf20f | 2987 | |
0dc262e0 | 2988 | return new_name; |
88dbf20f | 2989 | } |
2990 | ||
2991 | ||
278611f2 | 2992 | /* Mark virtual operands of FN for renaming by update_ssa. */ |
88dbf20f | 2993 | |
2994 | void | |
278611f2 | 2995 | mark_virtual_operands_for_renaming (struct function *fn) |
88dbf20f | 2996 | { |
278611f2 | 2997 | fn->gimple_df->ssa_renaming_needed = 1; |
2998 | fn->gimple_df->rename_vops = 1; | |
88dbf20f | 2999 | } |
3000 | ||
ba4d2b2f | 3001 | /* Replace all uses of NAME by underlying variable and mark it |
3002 | for renaming. This assumes the defining statement of NAME is | |
3003 | going to be removed. */ | |
3004 | ||
3005 | void | |
3006 | mark_virtual_operand_for_renaming (tree name) | |
3007 | { | |
3008 | tree name_var = SSA_NAME_VAR (name); | |
3009 | bool used = false; | |
3010 | imm_use_iterator iter; | |
3011 | use_operand_p use_p; | |
42acab1c | 3012 | gimple *stmt; |
ba4d2b2f | 3013 | |
3014 | gcc_assert (VAR_DECL_IS_VIRTUAL_OPERAND (name_var)); | |
3015 | FOR_EACH_IMM_USE_STMT (stmt, iter, name) | |
3016 | { | |
3017 | FOR_EACH_IMM_USE_ON_STMT (use_p, iter) | |
3018 | SET_USE (use_p, name_var); | |
3019 | used = true; | |
3020 | } | |
3021 | if (used) | |
3022 | mark_virtual_operands_for_renaming (cfun); | |
3023 | } | |
3024 | ||
3025 | /* Replace all uses of the virtual PHI result by its underlying variable | |
3026 | and mark it for renaming. This assumes the PHI node is going to be | |
3027 | removed. */ | |
3028 | ||
3029 | void | |
1a91d914 | 3030 | mark_virtual_phi_result_for_renaming (gphi *phi) |
ba4d2b2f | 3031 | { |
3032 | if (dump_file && (dump_flags & TDF_DETAILS)) | |
3033 | { | |
3034 | fprintf (dump_file, "Marking result for renaming : "); | |
3035 | print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
3036 | fprintf (dump_file, "\n"); | |
3037 | } | |
3038 | ||
3039 | mark_virtual_operand_for_renaming (gimple_phi_result (phi)); | |
3040 | } | |
88dbf20f | 3041 | |
dd277d48 | 3042 | /* Return true if there is any work to be done by update_ssa |
3043 | for function FN. */ | |
88dbf20f | 3044 | |
3045 | bool | |
dd277d48 | 3046 | need_ssa_update_p (struct function *fn) |
88dbf20f | 3047 | { |
dd277d48 | 3048 | gcc_assert (fn != NULL); |
3049 | return (update_ssa_initialized_fn == fn | |
e70e8b13 | 3050 | || (fn->gimple_df && fn->gimple_df->ssa_renaming_needed)); |
88dbf20f | 3051 | } |
3052 | ||
88dbf20f | 3053 | /* Return true if name N has been registered in the replacement table. */ |
3054 | ||
3055 | bool | |
75a70cf9 | 3056 | name_registered_for_update_p (tree n ATTRIBUTE_UNUSED) |
88dbf20f | 3057 | { |
dd277d48 | 3058 | if (!update_ssa_initialized_fn) |
88dbf20f | 3059 | return false; |
3060 | ||
dd277d48 | 3061 | gcc_assert (update_ssa_initialized_fn == cfun); |
3062 | ||
3063 | return is_new_name (n) || is_old_name (n); | |
88dbf20f | 3064 | } |
3065 | ||
3066 | ||
88dbf20f | 3067 | /* Mark NAME to be released after update_ssa has finished. */ |
3068 | ||
3069 | void | |
3070 | release_ssa_name_after_update_ssa (tree name) | |
3071 | { | |
dd277d48 | 3072 | gcc_assert (cfun && update_ssa_initialized_fn == cfun); |
88dbf20f | 3073 | |
3074 | if (names_to_release == NULL) | |
3075 | names_to_release = BITMAP_ALLOC (NULL); | |
3076 | ||
3077 | bitmap_set_bit (names_to_release, SSA_NAME_VERSION (name)); | |
3078 | } | |
3079 | ||
3080 | ||
3081 | /* Insert new PHI nodes to replace VAR. DFS contains dominance | |
3082 | frontier information. BLOCKS is the set of blocks to be updated. | |
3083 | ||
3084 | This is slightly different than the regular PHI insertion | |
3085 | algorithm. The value of UPDATE_FLAGS controls how PHI nodes for | |
3086 | real names (i.e., GIMPLE registers) are inserted: | |
48e1416a | 3087 | |
88dbf20f | 3088 | - If UPDATE_FLAGS == TODO_update_ssa, we are only interested in PHI |
3089 | nodes inside the region affected by the block that defines VAR | |
3090 | and the blocks that define all its replacements. All these | |
095dcfa3 | 3091 | definition blocks are stored in DEF_BLOCKS[VAR]->DEF_BLOCKS. |
88dbf20f | 3092 | |
3093 | First, we compute the entry point to the region (ENTRY). This is | |
3094 | given by the nearest common dominator to all the definition | |
3095 | blocks. When computing the iterated dominance frontier (IDF), any | |
3096 | block not strictly dominated by ENTRY is ignored. | |
3097 | ||
3098 | We then call the standard PHI insertion algorithm with the pruned | |
3099 | IDF. | |
3100 | ||
3101 | - If UPDATE_FLAGS == TODO_update_ssa_full_phi, the IDF for real | |
3102 | names is not pruned. PHI nodes are inserted at every IDF block. */ | |
3103 | ||
3104 | static void | |
8a2980be | 3105 | insert_updated_phi_nodes_for (tree var, bitmap_head *dfs, bitmap blocks, |
88dbf20f | 3106 | unsigned update_flags) |
3107 | { | |
3108 | basic_block entry; | |
04009ada | 3109 | def_blocks *db; |
88dbf20f | 3110 | bitmap idf, pruned_idf; |
3111 | bitmap_iterator bi; | |
3112 | unsigned i; | |
3113 | ||
88dbf20f | 3114 | if (TREE_CODE (var) == SSA_NAME) |
1b4345f7 | 3115 | gcc_checking_assert (is_old_name (var)); |
88dbf20f | 3116 | else |
e70e8b13 | 3117 | gcc_checking_assert (marked_for_renaming (var)); |
88dbf20f | 3118 | |
3119 | /* Get all the definition sites for VAR. */ | |
3120 | db = find_def_blocks_for (var); | |
3121 | ||
3122 | /* No need to do anything if there were no definitions to VAR. */ | |
3123 | if (db == NULL || bitmap_empty_p (db->def_blocks)) | |
3124 | return; | |
3125 | ||
3126 | /* Compute the initial iterated dominance frontier. */ | |
4fb5e5ca | 3127 | idf = compute_idf (db->def_blocks, dfs); |
88dbf20f | 3128 | pruned_idf = BITMAP_ALLOC (NULL); |
3129 | ||
3130 | if (TREE_CODE (var) == SSA_NAME) | |
3131 | { | |
3132 | if (update_flags == TODO_update_ssa) | |
3133 | { | |
3134 | /* If doing regular SSA updates for GIMPLE registers, we are | |
3135 | only interested in IDF blocks dominated by the nearest | |
3136 | common dominator of all the definition blocks. */ | |
3137 | entry = nearest_common_dominator_for_set (CDI_DOMINATORS, | |
3138 | db->def_blocks); | |
34154e27 | 3139 | if (entry != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
88dbf20f | 3140 | EXECUTE_IF_SET_IN_BITMAP (idf, 0, i, bi) |
f5a6b05f | 3141 | if (BASIC_BLOCK_FOR_FN (cfun, i) != entry |
3142 | && dominated_by_p (CDI_DOMINATORS, | |
3143 | BASIC_BLOCK_FOR_FN (cfun, i), entry)) | |
88dbf20f | 3144 | bitmap_set_bit (pruned_idf, i); |
3145 | } | |
3146 | else | |
3147 | { | |
3148 | /* Otherwise, do not prune the IDF for VAR. */ | |
88536563 | 3149 | gcc_checking_assert (update_flags == TODO_update_ssa_full_phi); |
88dbf20f | 3150 | bitmap_copy (pruned_idf, idf); |
3151 | } | |
3152 | } | |
3153 | else | |
3154 | { | |
3155 | /* Otherwise, VAR is a symbol that needs to be put into SSA form | |
3156 | for the first time, so we need to compute the full IDF for | |
3157 | it. */ | |
3158 | bitmap_copy (pruned_idf, idf); | |
88dbf20f | 3159 | } |
3160 | ||
3161 | if (!bitmap_empty_p (pruned_idf)) | |
3162 | { | |
3163 | /* Make sure that PRUNED_IDF blocks and all their feeding blocks | |
3164 | are included in the region to be updated. The feeding blocks | |
3165 | are important to guarantee that the PHI arguments are renamed | |
3166 | properly. */ | |
4fb5e5ca | 3167 | |
3168 | /* FIXME, this is not needed if we are updating symbols. We are | |
3169 | already starting at the ENTRY block anyway. */ | |
88dbf20f | 3170 | bitmap_ior_into (blocks, pruned_idf); |
3171 | EXECUTE_IF_SET_IN_BITMAP (pruned_idf, 0, i, bi) | |
3172 | { | |
3173 | edge e; | |
3174 | edge_iterator ei; | |
f5a6b05f | 3175 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, i); |
88dbf20f | 3176 | |
3177 | FOR_EACH_EDGE (e, ei, bb->preds) | |
3178 | if (e->src->index >= 0) | |
3179 | bitmap_set_bit (blocks, e->src->index); | |
3180 | } | |
3181 | ||
3182 | insert_phi_nodes_for (var, pruned_idf, true); | |
3183 | } | |
3184 | ||
3185 | BITMAP_FREE (pruned_idf); | |
3186 | BITMAP_FREE (idf); | |
3187 | } | |
3188 | ||
487c79c3 | 3189 | /* Sort symbols_to_rename after their DECL_UID. */ |
3190 | ||
3191 | static int | |
3192 | insert_updated_phi_nodes_compare_uids (const void *a, const void *b) | |
3193 | { | |
3194 | const_tree syma = *(const const_tree *)a; | |
3195 | const_tree symb = *(const const_tree *)b; | |
3196 | if (DECL_UID (syma) == DECL_UID (symb)) | |
3197 | return 0; | |
3198 | return DECL_UID (syma) < DECL_UID (symb) ? -1 : 1; | |
3199 | } | |
88dbf20f | 3200 | |
3201 | /* Given a set of newly created SSA names (NEW_SSA_NAMES) and a set of | |
3202 | existing SSA names (OLD_SSA_NAMES), update the SSA form so that: | |
3203 | ||
3204 | 1- The names in OLD_SSA_NAMES dominated by the definitions of | |
3205 | NEW_SSA_NAMES are all re-written to be reached by the | |
3206 | appropriate definition from NEW_SSA_NAMES. | |
3207 | ||
3208 | 2- If needed, new PHI nodes are added to the iterated dominance | |
3209 | frontier of the blocks where each of NEW_SSA_NAMES are defined. | |
3210 | ||
3211 | The mapping between OLD_SSA_NAMES and NEW_SSA_NAMES is setup by | |
0dc262e0 | 3212 | calling create_new_def_for to create new defs for names that the |
88dbf20f | 3213 | caller wants to replace. |
3214 | ||
0dc262e0 | 3215 | The caller cretaes the new names to be inserted and the names that need |
3216 | to be replaced by calling create_new_def_for for each old definition | |
3217 | to be replaced. Note that the function assumes that the | |
3218 | new defining statement has already been inserted in the IL. | |
88dbf20f | 3219 | |
3220 | For instance, given the following code: | |
3221 | ||
3222 | 1 L0: | |
3223 | 2 x_1 = PHI (0, x_5) | |
3224 | 3 if (x_1 < 10) | |
3225 | 4 if (x_1 > 7) | |
3226 | 5 y_2 = 0 | |
3227 | 6 else | |
3228 | 7 y_3 = x_1 + x_7 | |
3229 | 8 endif | |
3230 | 9 x_5 = x_1 + 1 | |
3231 | 10 goto L0; | |
3232 | 11 endif | |
3233 | ||
3234 | Suppose that we insert new names x_10 and x_11 (lines 4 and 8). | |
3235 | ||
3236 | 1 L0: | |
3237 | 2 x_1 = PHI (0, x_5) | |
3238 | 3 if (x_1 < 10) | |
3239 | 4 x_10 = ... | |
3240 | 5 if (x_1 > 7) | |
3241 | 6 y_2 = 0 | |
3242 | 7 else | |
3243 | 8 x_11 = ... | |
3244 | 9 y_3 = x_1 + x_7 | |
3245 | 10 endif | |
3246 | 11 x_5 = x_1 + 1 | |
3247 | 12 goto L0; | |
3248 | 13 endif | |
3249 | ||
3250 | We want to replace all the uses of x_1 with the new definitions of | |
3251 | x_10 and x_11. Note that the only uses that should be replaced are | |
3252 | those at lines 5, 9 and 11. Also, the use of x_7 at line 9 should | |
3253 | *not* be replaced (this is why we cannot just mark symbol 'x' for | |
3254 | renaming). | |
3255 | ||
3256 | Additionally, we may need to insert a PHI node at line 11 because | |
3257 | that is a merge point for x_10 and x_11. So the use of x_1 at line | |
3258 | 11 will be replaced with the new PHI node. The insertion of PHI | |
3259 | nodes is optional. They are not strictly necessary to preserve the | |
3260 | SSA form, and depending on what the caller inserted, they may not | |
3261 | even be useful for the optimizers. UPDATE_FLAGS controls various | |
3262 | aspects of how update_ssa operates, see the documentation for | |
3263 | TODO_update_ssa*. */ | |
3264 | ||
3265 | void | |
3266 | update_ssa (unsigned update_flags) | |
3267 | { | |
88dbf20f | 3268 | basic_block bb, start_bb; |
3269 | bitmap_iterator bi; | |
86c1585a | 3270 | unsigned i = 0; |
88dbf20f | 3271 | bool insert_phi_p; |
3e790786 | 3272 | sbitmap_iterator sbi; |
e70e8b13 | 3273 | tree sym; |
88dbf20f | 3274 | |
2670407e | 3275 | /* Only one update flag should be set. */ |
3276 | gcc_assert (update_flags == TODO_update_ssa | |
3277 | || update_flags == TODO_update_ssa_no_phi | |
3278 | || update_flags == TODO_update_ssa_full_phi | |
3279 | || update_flags == TODO_update_ssa_only_virtuals); | |
3280 | ||
dd277d48 | 3281 | if (!need_ssa_update_p (cfun)) |
88dbf20f | 3282 | return; |
3283 | ||
382ecba7 | 3284 | if (flag_checking) |
3285 | { | |
3286 | timevar_push (TV_TREE_STMT_VERIFY); | |
9e8385f4 | 3287 | |
382ecba7 | 3288 | bool err = false; |
9e8385f4 | 3289 | |
382ecba7 | 3290 | FOR_EACH_BB_FN (bb, cfun) |
9e8385f4 | 3291 | { |
382ecba7 | 3292 | gimple_stmt_iterator gsi; |
3293 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
9e8385f4 | 3294 | { |
382ecba7 | 3295 | gimple *stmt = gsi_stmt (gsi); |
9e8385f4 | 3296 | |
382ecba7 | 3297 | ssa_op_iter i; |
3298 | use_operand_p use_p; | |
3299 | FOR_EACH_SSA_USE_OPERAND (use_p, stmt, i, SSA_OP_ALL_USES) | |
9e8385f4 | 3300 | { |
382ecba7 | 3301 | tree use = USE_FROM_PTR (use_p); |
3302 | if (TREE_CODE (use) != SSA_NAME) | |
3303 | continue; | |
3304 | ||
3305 | if (SSA_NAME_IN_FREE_LIST (use)) | |
3306 | { | |
3307 | error ("statement uses released SSA name:"); | |
3308 | debug_gimple_stmt (stmt); | |
3309 | fprintf (stderr, "The use of "); | |
1ffa4346 | 3310 | print_generic_expr (stderr, use); |
382ecba7 | 3311 | fprintf (stderr," should have been replaced\n"); |
3312 | err = true; | |
3313 | } | |
9e8385f4 | 3314 | } |
3315 | } | |
3316 | } | |
9e8385f4 | 3317 | |
382ecba7 | 3318 | if (err) |
3319 | internal_error ("cannot update SSA form"); | |
9e8385f4 | 3320 | |
382ecba7 | 3321 | timevar_pop (TV_TREE_STMT_VERIFY); |
3322 | } | |
9e8385f4 | 3323 | |
88dbf20f | 3324 | timevar_push (TV_TREE_SSA_INCREMENTAL); |
3325 | ||
0ffbb1b6 | 3326 | if (dump_file && (dump_flags & TDF_DETAILS)) |
3327 | fprintf (dump_file, "\nUpdating SSA:\n"); | |
3328 | ||
dd277d48 | 3329 | if (!update_ssa_initialized_fn) |
3330 | init_update_ssa (cfun); | |
2670407e | 3331 | else if (update_flags == TODO_update_ssa_only_virtuals) |
3332 | { | |
3333 | /* If we only need to update virtuals, remove all the mappings for | |
3334 | real names before proceeding. The caller is responsible for | |
3335 | having dealt with the name mappings before calling update_ssa. */ | |
53c5d9d4 | 3336 | bitmap_clear (old_ssa_names); |
3337 | bitmap_clear (new_ssa_names); | |
2670407e | 3338 | } |
3339 | ||
dd277d48 | 3340 | gcc_assert (update_ssa_initialized_fn == cfun); |
3341 | ||
70630fcd | 3342 | blocks_with_phis_to_rewrite = BITMAP_ALLOC (NULL); |
f1f41a6c | 3343 | if (!phis_to_rewrite.exists ()) |
fe672ac0 | 3344 | phis_to_rewrite.create (last_basic_block_for_fn (cfun) + 1); |
2920559d | 3345 | blocks_to_update = BITMAP_ALLOC (NULL); |
70630fcd | 3346 | |
88dbf20f | 3347 | /* Ensure that the dominance information is up-to-date. */ |
3348 | calculate_dominance_info (CDI_DOMINATORS); | |
3349 | ||
095dcfa3 | 3350 | insert_phi_p = (update_flags != TODO_update_ssa_no_phi); |
88dbf20f | 3351 | |
095dcfa3 | 3352 | /* If there are names defined in the replacement table, prepare |
3353 | definition and use sites for all the names in NEW_SSA_NAMES and | |
3354 | OLD_SSA_NAMES. */ | |
53c5d9d4 | 3355 | if (bitmap_first_set_bit (new_ssa_names) >= 0) |
095dcfa3 | 3356 | { |
b35a87b1 | 3357 | statistics_counter_event (cfun, "Incremental SSA update", 1); |
3358 | ||
2920559d | 3359 | prepare_names_to_update (insert_phi_p); |
095dcfa3 | 3360 | |
3361 | /* If all the names in NEW_SSA_NAMES had been marked for | |
3362 | removal, and there are no symbols to rename, then there's | |
3363 | nothing else to do. */ | |
53c5d9d4 | 3364 | if (bitmap_first_set_bit (new_ssa_names) < 0 |
e70e8b13 | 3365 | && !cfun->gimple_df->ssa_renaming_needed) |
095dcfa3 | 3366 | goto done; |
3367 | } | |
3368 | ||
3369 | /* Next, determine the block at which to start the renaming process. */ | |
e70e8b13 | 3370 | if (cfun->gimple_df->ssa_renaming_needed) |
095dcfa3 | 3371 | { |
b35a87b1 | 3372 | statistics_counter_event (cfun, "Symbol to SSA rewrite", 1); |
3373 | ||
22d6c74e | 3374 | /* If we rename bare symbols initialize the mapping to |
3375 | auxiliar info we need to keep track of. */ | |
c1f445d2 | 3376 | var_infos = new hash_table<var_info_hasher> (47); |
22d6c74e | 3377 | |
095dcfa3 | 3378 | /* If we have to rename some symbols from scratch, we need to |
3379 | start the process at the root of the CFG. FIXME, it should | |
3380 | be possible to determine the nearest block that had a | |
3381 | definition for each of the symbols that are marked for | |
3382 | updating. For now this seems more work than it's worth. */ | |
34154e27 | 3383 | start_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
095dcfa3 | 3384 | |
4fb5e5ca | 3385 | /* Traverse the CFG looking for existing definitions and uses of |
e70e8b13 | 3386 | symbols in SSA operands. Mark interesting blocks and |
4fb5e5ca | 3387 | statements and set local live-in information for the PHI |
3388 | placement heuristics. */ | |
2920559d | 3389 | prepare_block_for_update (start_bb, insert_phi_p); |
f8aa507d | 3390 | |
f211616e | 3391 | tree name; |
3392 | ||
382ecba7 | 3393 | if (flag_checking) |
f211616e | 3394 | FOR_EACH_SSA_NAME (i, name, cfun) |
382ecba7 | 3395 | { |
f211616e | 3396 | if (virtual_operand_p (name)) |
382ecba7 | 3397 | continue; |
3398 | ||
3399 | /* For all but virtual operands, which do not have SSA names | |
3400 | with overlapping life ranges, ensure that symbols marked | |
3401 | for renaming do not have existing SSA names associated with | |
3402 | them as we do not re-write them out-of-SSA before going | |
3403 | into SSA for the remaining symbol uses. */ | |
3404 | if (marked_for_renaming (SSA_NAME_VAR (name))) | |
3405 | { | |
3406 | fprintf (stderr, "Existing SSA name for symbol marked for " | |
3407 | "renaming: "); | |
3408 | print_generic_expr (stderr, name, TDF_SLIM); | |
3409 | fprintf (stderr, "\n"); | |
3410 | internal_error ("SSA corruption"); | |
3411 | } | |
3412 | } | |
88dbf20f | 3413 | } |
3414 | else | |
095dcfa3 | 3415 | { |
3416 | /* Otherwise, the entry block to the region is the nearest | |
3417 | common dominator for the blocks in BLOCKS. */ | |
2920559d | 3418 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3419 | blocks_to_update); | |
095dcfa3 | 3420 | } |
88dbf20f | 3421 | |
3422 | /* If requested, insert PHI nodes at the iterated dominance frontier | |
095dcfa3 | 3423 | of every block, creating new definitions for names in OLD_SSA_NAMES |
e70e8b13 | 3424 | and for symbols found. */ |
88dbf20f | 3425 | if (insert_phi_p) |
3426 | { | |
8a2980be | 3427 | bitmap_head *dfs; |
66d00abf | 3428 | |
3429 | /* If the caller requested PHI nodes to be added, compute | |
3430 | dominance frontiers. */ | |
fe672ac0 | 3431 | dfs = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
fc00614f | 3432 | FOR_EACH_BB_FN (bb, cfun) |
8a2980be | 3433 | bitmap_initialize (&dfs[bb->index], &bitmap_default_obstack); |
66d00abf | 3434 | compute_dominance_frontiers (dfs); |
3435 | ||
53c5d9d4 | 3436 | if (bitmap_first_set_bit (old_ssa_names) >= 0) |
88dbf20f | 3437 | { |
3e790786 | 3438 | sbitmap_iterator sbi; |
3439 | ||
095dcfa3 | 3440 | /* insert_update_phi_nodes_for will call add_new_name_mapping |
3441 | when inserting new PHI nodes, so the set OLD_SSA_NAMES | |
3442 | will grow while we are traversing it (but it will not | |
3443 | gain any new members). Copy OLD_SSA_NAMES to a temporary | |
3444 | for traversal. */ | |
3c6549f8 | 3445 | auto_sbitmap tmp (SBITMAP_SIZE (old_ssa_names)); |
53c5d9d4 | 3446 | bitmap_copy (tmp, old_ssa_names); |
0d211963 | 3447 | EXECUTE_IF_SET_IN_BITMAP (tmp, 0, i, sbi) |
2920559d | 3448 | insert_updated_phi_nodes_for (ssa_name (i), dfs, blocks_to_update, |
3e790786 | 3449 | update_flags); |
88dbf20f | 3450 | } |
3451 | ||
487c79c3 | 3452 | symbols_to_rename.qsort (insert_updated_phi_nodes_compare_uids); |
f1f41a6c | 3453 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
e70e8b13 | 3454 | insert_updated_phi_nodes_for (sym, dfs, blocks_to_update, |
4fb5e5ca | 3455 | update_flags); |
88dbf20f | 3456 | |
fc00614f | 3457 | FOR_EACH_BB_FN (bb, cfun) |
8a2980be | 3458 | bitmap_clear (&dfs[bb->index]); |
66d00abf | 3459 | free (dfs); |
3460 | ||
88dbf20f | 3461 | /* Insertion of PHI nodes may have added blocks to the region. |
3462 | We need to re-compute START_BB to include the newly added | |
3463 | blocks. */ | |
34154e27 | 3464 | if (start_bb != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
2920559d | 3465 | start_bb = nearest_common_dominator_for_set (CDI_DOMINATORS, |
3466 | blocks_to_update); | |
88dbf20f | 3467 | } |
3468 | ||
3469 | /* Reset the current definition for name and symbol before renaming | |
3470 | the sub-graph. */ | |
0d211963 | 3471 | EXECUTE_IF_SET_IN_BITMAP (old_ssa_names, 0, i, sbi) |
74105c0d | 3472 | get_ssa_name_ann (ssa_name (i))->info.current_def = NULL_TREE; |
88dbf20f | 3473 | |
f1f41a6c | 3474 | FOR_EACH_VEC_ELT (symbols_to_rename, i, sym) |
74105c0d | 3475 | get_var_info (sym)->info.current_def = NULL_TREE; |
88dbf20f | 3476 | |
3477 | /* Now start the renaming process at START_BB. */ | |
fe672ac0 | 3478 | interesting_blocks = sbitmap_alloc (last_basic_block_for_fn (cfun)); |
53c5d9d4 | 3479 | bitmap_clear (interesting_blocks); |
2920559d | 3480 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
08b7917c | 3481 | bitmap_set_bit (interesting_blocks, i); |
88dbf20f | 3482 | |
6bf320fb | 3483 | rewrite_blocks (start_bb, REWRITE_UPDATE); |
88dbf20f | 3484 | |
6bf320fb | 3485 | sbitmap_free (interesting_blocks); |
88dbf20f | 3486 | |
3487 | /* Debugging dumps. */ | |
3488 | if (dump_file) | |
3489 | { | |
3490 | int c; | |
3491 | unsigned i; | |
3492 | ||
095dcfa3 | 3493 | dump_update_ssa (dump_file); |
88dbf20f | 3494 | |
0ffbb1b6 | 3495 | fprintf (dump_file, "Incremental SSA update started at block: %d\n", |
88dbf20f | 3496 | start_bb->index); |
3497 | ||
3498 | c = 0; | |
2920559d | 3499 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
88dbf20f | 3500 | c++; |
fe672ac0 | 3501 | fprintf (dump_file, "Number of blocks in CFG: %d\n", |
3502 | last_basic_block_for_fn (cfun)); | |
0ffbb1b6 | 3503 | fprintf (dump_file, "Number of blocks to update: %d (%3.0f%%)\n", |
fe672ac0 | 3504 | c, PERCENT (c, last_basic_block_for_fn (cfun))); |
88dbf20f | 3505 | |
3506 | if (dump_flags & TDF_DETAILS) | |
3507 | { | |
7ef97146 | 3508 | fprintf (dump_file, "Affected blocks:"); |
2920559d | 3509 | EXECUTE_IF_SET_IN_BITMAP (blocks_to_update, 0, i, bi) |
7ef97146 | 3510 | fprintf (dump_file, " %u", i); |
88dbf20f | 3511 | fprintf (dump_file, "\n"); |
3512 | } | |
3513 | ||
3514 | fprintf (dump_file, "\n\n"); | |
3515 | } | |
3516 | ||
3517 | /* Free allocated memory. */ | |
095dcfa3 | 3518 | done: |
88dbf20f | 3519 | delete_update_ssa (); |
3520 | ||
3521 | timevar_pop (TV_TREE_SSA_INCREMENTAL); | |
3522 | } |