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4ee9c684 | 1 | /* Liveness for SSA trees. |
711789cc | 2 | Copyright (C) 2003-2013 Free Software Foundation, Inc. |
4ee9c684 | 3 | Contributed by Andrew MacLeod <amacleod@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" | |
d9dd21a8 | 24 | #include "hash-table.h" |
4ee9c684 | 25 | #include "tm.h" |
26 | #include "tree.h" | |
ce084dfc | 27 | #include "gimple-pretty-print.h" |
4ee9c684 | 28 | #include "bitmap.h" |
424a4a92 | 29 | #include "sbitmap.h" |
bc61cadb | 30 | #include "basic-block.h" |
31 | #include "tree-ssa-alias.h" | |
32 | #include "internal-fn.h" | |
33 | #include "gimple-expr.h" | |
34 | #include "is-a.h" | |
073c1fd5 | 35 | #include "gimple.h" |
dcf1a1ec | 36 | #include "gimple-iterator.h" |
073c1fd5 | 37 | #include "gimple-ssa.h" |
38 | #include "tree-phinodes.h" | |
39 | #include "ssa-iterators.h" | |
9ed99284 | 40 | #include "stringpool.h" |
073c1fd5 | 41 | #include "tree-ssanames.h" |
9ed99284 | 42 | #include "expr.h" |
073c1fd5 | 43 | #include "tree-dfa.h" |
b9ed1410 | 44 | #include "timevar.h" |
45 | #include "dumpfile.h" | |
4ee9c684 | 46 | #include "tree-ssa-live.h" |
0b205f4c | 47 | #include "diagnostic-core.h" |
2ff2a12b | 48 | #include "debug.h" |
49 | #include "flags.h" | |
2d043327 | 50 | |
30928c44 | 51 | #ifdef ENABLE_CHECKING |
52 | static void verify_live_on_entry (tree_live_info_p); | |
53 | #endif | |
4ee9c684 | 54 | |
4ee9c684 | 55 | |
2d043327 | 56 | /* VARMAP maintains a mapping from SSA version number to real variables. |
57 | ||
58 | All SSA_NAMES are divided into partitions. Initially each ssa_name is the | |
59 | only member of it's own partition. Coalescing will attempt to group any | |
60 | ssa_names which occur in a copy or in a PHI node into the same partition. | |
61 | ||
62 | At the end of out-of-ssa, each partition becomes a "real" variable and is | |
63 | rewritten as a compiler variable. | |
64 | ||
f0b5f617 | 65 | The var_map data structure is used to manage these partitions. It allows |
2d043327 | 66 | partitions to be combined, and determines which partition belongs to what |
67 | ssa_name or variable, and vice versa. */ | |
68 | ||
69 | ||
d9dd21a8 | 70 | /* Hashtable helpers. */ |
71 | ||
72 | struct tree_int_map_hasher : typed_noop_remove <tree_int_map> | |
73 | { | |
74 | typedef tree_int_map value_type; | |
75 | typedef tree_int_map compare_type; | |
76 | static inline hashval_t hash (const value_type *); | |
77 | static inline bool equal (const value_type *, const compare_type *); | |
78 | }; | |
79 | ||
80 | inline hashval_t | |
81 | tree_int_map_hasher::hash (const value_type *v) | |
82 | { | |
83 | return tree_map_base_hash (v); | |
84 | } | |
85 | ||
86 | inline bool | |
87 | tree_int_map_hasher::equal (const value_type *v, const compare_type *c) | |
88 | { | |
89 | return tree_int_map_eq (v, c); | |
90 | } | |
91 | ||
92 | ||
2d043327 | 93 | /* This routine will initialize the basevar fields of MAP. */ |
94 | ||
95 | static void | |
96 | var_map_base_init (var_map map) | |
97 | { | |
4ae5778c | 98 | int x, num_part; |
2d043327 | 99 | tree var; |
d9dd21a8 | 100 | hash_table <tree_int_map_hasher> tree_to_index; |
4ae5778c | 101 | struct tree_int_map *m, *mapstorage; |
48e1416a | 102 | |
2d043327 | 103 | num_part = num_var_partitions (map); |
d9dd21a8 | 104 | tree_to_index.create (num_part); |
4ae5778c | 105 | /* We can have at most num_part entries in the hash tables, so it's |
106 | enough to allocate so many map elements once, saving some malloc | |
107 | calls. */ | |
108 | mapstorage = m = XNEWVEC (struct tree_int_map, num_part); | |
2d043327 | 109 | |
110 | /* If a base table already exists, clear it, otherwise create it. */ | |
4ae5778c | 111 | free (map->partition_to_base_index); |
2d043327 | 112 | map->partition_to_base_index = (int *) xmalloc (sizeof (int) * num_part); |
113 | ||
114 | /* Build the base variable list, and point partitions at their bases. */ | |
115 | for (x = 0; x < num_part; x++) | |
116 | { | |
4ae5778c | 117 | struct tree_int_map **slot; |
118 | unsigned baseindex; | |
2d043327 | 119 | var = partition_to_var (map, x); |
688425e8 | 120 | if (SSA_NAME_VAR (var) |
121 | && (!VAR_P (SSA_NAME_VAR (var)) | |
122 | || !DECL_IGNORED_P (SSA_NAME_VAR (var)))) | |
ec11736b | 123 | m->base.from = SSA_NAME_VAR (var); |
124 | else | |
125 | /* This restricts what anonymous SSA names we can coalesce | |
126 | as it restricts the sets we compute conflicts for. | |
127 | Using TREE_TYPE to generate sets is the easies as | |
128 | type equivalency also holds for SSA names with the same | |
f82f0ea5 | 129 | underlying decl. |
130 | ||
131 | Check gimple_can_coalesce_p when changing this code. */ | |
132 | m->base.from = (TYPE_CANONICAL (TREE_TYPE (var)) | |
133 | ? TYPE_CANONICAL (TREE_TYPE (var)) | |
134 | : TREE_TYPE (var)); | |
2d043327 | 135 | /* If base variable hasn't been seen, set it up. */ |
d9dd21a8 | 136 | slot = tree_to_index.find_slot (m, INSERT); |
4ae5778c | 137 | if (!*slot) |
138 | { | |
139 | baseindex = m - mapstorage; | |
140 | m->to = baseindex; | |
141 | *slot = m; | |
142 | m++; | |
2d043327 | 143 | } |
4ae5778c | 144 | else |
145 | baseindex = (*slot)->to; | |
146 | map->partition_to_base_index[x] = baseindex; | |
2d043327 | 147 | } |
148 | ||
4ae5778c | 149 | map->num_basevars = m - mapstorage; |
2d043327 | 150 | |
4ae5778c | 151 | free (mapstorage); |
d9dd21a8 | 152 | tree_to_index. dispose (); |
2d043327 | 153 | } |
154 | ||
4ee9c684 | 155 | |
2d043327 | 156 | /* Remove the base table in MAP. */ |
4ee9c684 | 157 | |
2d043327 | 158 | static void |
159 | var_map_base_fini (var_map map) | |
160 | { | |
161 | /* Free the basevar info if it is present. */ | |
162 | if (map->partition_to_base_index != NULL) | |
163 | { | |
2d043327 | 164 | free (map->partition_to_base_index); |
165 | map->partition_to_base_index = NULL; | |
166 | map->num_basevars = 0; | |
167 | } | |
168 | } | |
4ee9c684 | 169 | /* Create a variable partition map of SIZE, initialize and return it. */ |
170 | ||
171 | var_map | |
172 | init_var_map (int size) | |
173 | { | |
174 | var_map map; | |
175 | ||
176 | map = (var_map) xmalloc (sizeof (struct _var_map)); | |
177 | map->var_partition = partition_new (size); | |
4ee9c684 | 178 | |
2d043327 | 179 | map->partition_to_view = NULL; |
180 | map->view_to_partition = NULL; | |
4ee9c684 | 181 | map->num_partitions = size; |
182 | map->partition_size = size; | |
2d043327 | 183 | map->num_basevars = 0; |
184 | map->partition_to_base_index = NULL; | |
4ee9c684 | 185 | return map; |
186 | } | |
187 | ||
188 | ||
189 | /* Free memory associated with MAP. */ | |
190 | ||
191 | void | |
192 | delete_var_map (var_map map) | |
193 | { | |
2d043327 | 194 | var_map_base_fini (map); |
4ee9c684 | 195 | partition_delete (map->var_partition); |
dd045aee | 196 | free (map->partition_to_view); |
197 | free (map->view_to_partition); | |
4ee9c684 | 198 | free (map); |
199 | } | |
200 | ||
201 | ||
48e1416a | 202 | /* This function will combine the partitions in MAP for VAR1 and VAR2. It |
203 | Returns the partition which represents the new partition. If the two | |
0bed3869 | 204 | partitions cannot be combined, NO_PARTITION is returned. */ |
4ee9c684 | 205 | |
206 | int | |
207 | var_union (var_map map, tree var1, tree var2) | |
208 | { | |
209 | int p1, p2, p3; | |
a8dd994c | 210 | |
211 | gcc_assert (TREE_CODE (var1) == SSA_NAME); | |
212 | gcc_assert (TREE_CODE (var2) == SSA_NAME); | |
4ee9c684 | 213 | |
48e1416a | 214 | /* This is independent of partition_to_view. If partition_to_view is |
4ee9c684 | 215 | on, then whichever one of these partitions is absorbed will never have a |
2d043327 | 216 | dereference into the partition_to_view array any more. */ |
4ee9c684 | 217 | |
a8dd994c | 218 | p1 = partition_find (map->var_partition, SSA_NAME_VERSION (var1)); |
219 | p2 = partition_find (map->var_partition, SSA_NAME_VERSION (var2)); | |
4ee9c684 | 220 | |
8c0963c4 | 221 | gcc_assert (p1 != NO_PARTITION); |
222 | gcc_assert (p2 != NO_PARTITION); | |
4ee9c684 | 223 | |
224 | if (p1 == p2) | |
225 | p3 = p1; | |
226 | else | |
227 | p3 = partition_union (map->var_partition, p1, p2); | |
228 | ||
2d043327 | 229 | if (map->partition_to_view) |
230 | p3 = map->partition_to_view[p3]; | |
4ee9c684 | 231 | |
4ee9c684 | 232 | return p3; |
233 | } | |
234 | ||
48e1416a | 235 | |
236 | /* Compress the partition numbers in MAP such that they fall in the range | |
4ee9c684 | 237 | 0..(num_partitions-1) instead of wherever they turned out during |
238 | the partitioning exercise. This removes any references to unused | |
239 | partitions, thereby allowing bitmaps and other vectors to be much | |
48e1416a | 240 | denser. |
4ee9c684 | 241 | |
242 | This is implemented such that compaction doesn't affect partitioning. | |
243 | Ie., once partitions are created and possibly merged, running one | |
244 | or more different kind of compaction will not affect the partitions | |
245 | themselves. Their index might change, but all the same variables will | |
246 | still be members of the same partition group. This allows work on reduced | |
247 | sets, and no loss of information when a larger set is later desired. | |
248 | ||
249 | In particular, coalescing can work on partitions which have 2 or more | |
250 | definitions, and then 'recompact' later to include all the single | |
251 | definitions for assignment to program variables. */ | |
252 | ||
2d043327 | 253 | |
48e1416a | 254 | /* Set MAP back to the initial state of having no partition view. Return a |
255 | bitmap which has a bit set for each partition number which is in use in the | |
2d043327 | 256 | varmap. */ |
257 | ||
258 | static bitmap | |
259 | partition_view_init (var_map map) | |
4ee9c684 | 260 | { |
2d043327 | 261 | bitmap used; |
262 | int tmp; | |
263 | unsigned int x; | |
4ee9c684 | 264 | |
2d043327 | 265 | used = BITMAP_ALLOC (NULL); |
4ee9c684 | 266 | |
2d043327 | 267 | /* Already in a view? Abandon the old one. */ |
268 | if (map->partition_to_view) | |
4ee9c684 | 269 | { |
2d043327 | 270 | free (map->partition_to_view); |
271 | map->partition_to_view = NULL; | |
4ee9c684 | 272 | } |
2d043327 | 273 | if (map->view_to_partition) |
4ee9c684 | 274 | { |
2d043327 | 275 | free (map->view_to_partition); |
276 | map->view_to_partition = NULL; | |
4ee9c684 | 277 | } |
278 | ||
4ee9c684 | 279 | /* Find out which partitions are actually referenced. */ |
2d043327 | 280 | for (x = 0; x < map->partition_size; x++) |
4ee9c684 | 281 | { |
282 | tmp = partition_find (map->var_partition, x); | |
7c782c9b | 283 | if (ssa_name (tmp) != NULL_TREE && !virtual_operand_p (ssa_name (tmp)) |
a8dd994c | 284 | && (!has_zero_uses (ssa_name (tmp)) |
285 | || !SSA_NAME_IS_DEFAULT_DEF (ssa_name (tmp)))) | |
2d043327 | 286 | bitmap_set_bit (used, tmp); |
4ee9c684 | 287 | } |
288 | ||
2d043327 | 289 | map->num_partitions = map->partition_size; |
290 | return used; | |
291 | } | |
292 | ||
293 | ||
294 | /* This routine will finalize the view data for MAP based on the partitions | |
48e1416a | 295 | set in SELECTED. This is either the same bitmap returned from |
2d043327 | 296 | partition_view_init, or a trimmed down version if some of those partitions |
297 | were not desired in this view. SELECTED is freed before returning. */ | |
298 | ||
48e1416a | 299 | static void |
2d043327 | 300 | partition_view_fini (var_map map, bitmap selected) |
301 | { | |
302 | bitmap_iterator bi; | |
303 | unsigned count, i, x, limit; | |
2d043327 | 304 | |
305 | gcc_assert (selected); | |
306 | ||
307 | count = bitmap_count_bits (selected); | |
308 | limit = map->partition_size; | |
309 | ||
310 | /* If its a one-to-one ratio, we don't need any view compaction. */ | |
311 | if (count < limit) | |
4ee9c684 | 312 | { |
2d043327 | 313 | map->partition_to_view = (int *)xmalloc (limit * sizeof (int)); |
314 | memset (map->partition_to_view, 0xff, (limit * sizeof (int))); | |
315 | map->view_to_partition = (int *)xmalloc (count * sizeof (int)); | |
3e790786 | 316 | |
2d043327 | 317 | i = 0; |
318 | /* Give each selected partition an index. */ | |
319 | EXECUTE_IF_SET_IN_BITMAP (selected, 0, x, bi) | |
4ee9c684 | 320 | { |
2d043327 | 321 | map->partition_to_view[x] = i; |
322 | map->view_to_partition[i] = x; | |
2d043327 | 323 | i++; |
3e790786 | 324 | } |
2d043327 | 325 | gcc_assert (i == count); |
326 | map->num_partitions = i; | |
4ee9c684 | 327 | } |
2d043327 | 328 | |
329 | BITMAP_FREE (selected); | |
330 | } | |
331 | ||
332 | ||
48e1416a | 333 | /* Create a partition view which includes all the used partitions in MAP. If |
2d043327 | 334 | WANT_BASES is true, create the base variable map as well. */ |
335 | ||
4fb07d00 | 336 | void |
2d043327 | 337 | partition_view_normal (var_map map, bool want_bases) |
338 | { | |
339 | bitmap used; | |
340 | ||
341 | used = partition_view_init (map); | |
342 | partition_view_fini (map, used); | |
343 | ||
344 | if (want_bases) | |
345 | var_map_base_init (map); | |
4ee9c684 | 346 | else |
2d043327 | 347 | var_map_base_fini (map); |
348 | } | |
349 | ||
350 | ||
48e1416a | 351 | /* Create a partition view in MAP which includes just partitions which occur in |
352 | the bitmap ONLY. If WANT_BASES is true, create the base variable map | |
2d043327 | 353 | as well. */ |
354 | ||
4fb07d00 | 355 | void |
2d043327 | 356 | partition_view_bitmap (var_map map, bitmap only, bool want_bases) |
357 | { | |
358 | bitmap used; | |
359 | bitmap new_partitions = BITMAP_ALLOC (NULL); | |
360 | unsigned x, p; | |
361 | bitmap_iterator bi; | |
362 | ||
363 | used = partition_view_init (map); | |
364 | EXECUTE_IF_SET_IN_BITMAP (only, 0, x, bi) | |
4ee9c684 | 365 | { |
2d043327 | 366 | p = partition_find (map->var_partition, x); |
367 | gcc_assert (bitmap_bit_p (used, p)); | |
368 | bitmap_set_bit (new_partitions, p); | |
4ee9c684 | 369 | } |
2d043327 | 370 | partition_view_fini (map, new_partitions); |
4ee9c684 | 371 | |
2d043327 | 372 | if (want_bases) |
373 | var_map_base_init (map); | |
374 | else | |
375 | var_map_base_fini (map); | |
4ee9c684 | 376 | } |
377 | ||
378 | ||
4ae5778c | 379 | static bitmap usedvars; |
380 | ||
920bd157 | 381 | /* Mark VAR as used, so that it'll be preserved during rtl expansion. |
382 | Returns true if VAR wasn't marked before. */ | |
4ae5778c | 383 | |
920bd157 | 384 | static inline bool |
4ae5778c | 385 | set_is_used (tree var) |
386 | { | |
920bd157 | 387 | return bitmap_set_bit (usedvars, DECL_UID (var)); |
4ae5778c | 388 | } |
389 | ||
390 | /* Return true if VAR is marked as used. */ | |
391 | ||
392 | static inline bool | |
393 | is_used_p (tree var) | |
394 | { | |
395 | return bitmap_bit_p (usedvars, DECL_UID (var)); | |
396 | } | |
397 | ||
920bd157 | 398 | static inline void mark_all_vars_used (tree *); |
4ee9c684 | 399 | |
280450fa | 400 | /* Helper function for mark_all_vars_used, called via walk_tree. */ |
401 | ||
402 | static tree | |
920bd157 | 403 | mark_all_vars_used_1 (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED) |
280450fa | 404 | { |
405 | tree t = *tp; | |
2ff2a12b | 406 | enum tree_code_class c = TREE_CODE_CLASS (TREE_CODE (t)); |
407 | tree b; | |
280450fa | 408 | |
db22d3cc | 409 | if (TREE_CODE (t) == SSA_NAME) |
ec11736b | 410 | { |
411 | *walk_subtrees = 0; | |
412 | t = SSA_NAME_VAR (t); | |
413 | if (!t) | |
414 | return NULL; | |
415 | } | |
75a70cf9 | 416 | |
417 | if (IS_EXPR_CODE_CLASS (c) | |
2ff2a12b | 418 | && (b = TREE_BLOCK (t)) != NULL) |
419 | TREE_USED (b) = true; | |
db22d3cc | 420 | |
28daba6f | 421 | /* Ignore TMR_OFFSET and TMR_STEP for TARGET_MEM_REFS, as those |
422 | fields do not contain vars. */ | |
b06d1934 | 423 | if (TREE_CODE (t) == TARGET_MEM_REF) |
424 | { | |
920bd157 | 425 | mark_all_vars_used (&TMR_BASE (t)); |
426 | mark_all_vars_used (&TMR_INDEX (t)); | |
427 | mark_all_vars_used (&TMR_INDEX2 (t)); | |
b06d1934 | 428 | *walk_subtrees = 0; |
429 | return NULL; | |
430 | } | |
431 | ||
280450fa | 432 | /* Only need to mark VAR_DECLS; parameters and return results are not |
433 | eliminated as unused. */ | |
434 | if (TREE_CODE (t) == VAR_DECL) | |
a93b21ea | 435 | { |
920bd157 | 436 | /* When a global var becomes used for the first time also walk its |
437 | initializer (non global ones don't have any). */ | |
438 | if (set_is_used (t) && is_global_var (t)) | |
439 | mark_all_vars_used (&DECL_INITIAL (t)); | |
a93b21ea | 440 | } |
6ceec668 | 441 | /* remove_unused_scope_block_p requires information about labels |
442 | which are not DECL_IGNORED_P to tell if they might be used in the IL. */ | |
ad75582e | 443 | else if (TREE_CODE (t) == LABEL_DECL) |
6ceec668 | 444 | /* Although the TREE_USED values that the frontend uses would be |
445 | acceptable (albeit slightly over-conservative) for our purposes, | |
446 | init_vars_expansion clears TREE_USED for LABEL_DECLs too, so we | |
447 | must re-compute it here. */ | |
448 | TREE_USED (t) = 1; | |
280450fa | 449 | |
ce45a448 | 450 | if (IS_TYPE_OR_DECL_P (t)) |
280450fa | 451 | *walk_subtrees = 0; |
452 | ||
453 | return NULL; | |
454 | } | |
455 | ||
2ff2a12b | 456 | /* Mark the scope block SCOPE and its subblocks unused when they can be |
457 | possibly eliminated if dead. */ | |
458 | ||
459 | static void | |
460 | mark_scope_block_unused (tree scope) | |
461 | { | |
462 | tree t; | |
463 | TREE_USED (scope) = false; | |
464 | if (!(*debug_hooks->ignore_block) (scope)) | |
465 | TREE_USED (scope) = true; | |
466 | for (t = BLOCK_SUBBLOCKS (scope); t ; t = BLOCK_CHAIN (t)) | |
467 | mark_scope_block_unused (t); | |
468 | } | |
469 | ||
470 | /* Look if the block is dead (by possibly eliminating its dead subblocks) | |
48e1416a | 471 | and return true if so. |
2ff2a12b | 472 | Block is declared dead if: |
473 | 1) No statements are associated with it. | |
474 | 2) Declares no live variables | |
475 | 3) All subblocks are dead | |
476 | or there is precisely one subblocks and the block | |
477 | has same abstract origin as outer block and declares | |
478 | no variables, so it is pure wrapper. | |
4a7e4fcc | 479 | When we are not outputting full debug info, we also eliminate dead variables |
2ff2a12b | 480 | out of scope blocks to let them to be recycled by GGC and to save copying work |
481 | done by the inliner. */ | |
482 | ||
483 | static bool | |
920bd157 | 484 | remove_unused_scope_block_p (tree scope) |
2ff2a12b | 485 | { |
8c796c7c | 486 | tree *t, *next; |
2ff2a12b | 487 | bool unused = !TREE_USED (scope); |
2ff2a12b | 488 | int nsubblocks = 0; |
489 | ||
8c796c7c | 490 | for (t = &BLOCK_VARS (scope); *t; t = next) |
491 | { | |
1767a056 | 492 | next = &DECL_CHAIN (*t); |
8c796c7c | 493 | |
494 | /* Debug info of nested function refers to the block of the | |
36267649 | 495 | function. We might stil call it even if all statements |
496 | of function it was nested into was elliminated. | |
48e1416a | 497 | |
36267649 | 498 | TODO: We can actually look into cgraph to see if function |
499 | will be output to file. */ | |
8c796c7c | 500 | if (TREE_CODE (*t) == FUNCTION_DECL) |
501 | unused = false; | |
ee093c13 | 502 | |
503 | /* If a decl has a value expr, we need to instantiate it | |
504 | regardless of debug info generation, to avoid codegen | |
505 | differences in memory overlap tests. update_equiv_regs() may | |
506 | indirectly call validate_equiv_mem() to test whether a | |
507 | SET_DEST overlaps with others, and if the value expr changes | |
508 | by virtual register instantiation, we may get end up with | |
509 | different results. */ | |
510 | else if (TREE_CODE (*t) == VAR_DECL && DECL_HAS_VALUE_EXPR_P (*t)) | |
511 | unused = false; | |
512 | ||
25db41e9 | 513 | /* Remove everything we don't generate debug info for. */ |
514 | else if (DECL_IGNORED_P (*t)) | |
64f6c8c9 | 515 | { |
1767a056 | 516 | *t = DECL_CHAIN (*t); |
64f6c8c9 | 517 | next = t; |
518 | } | |
519 | ||
8c796c7c | 520 | /* When we are outputting debug info, we usually want to output |
521 | info about optimized-out variables in the scope blocks. | |
522 | Exception are the scope blocks not containing any instructions | |
523 | at all so user can't get into the scopes at first place. */ | |
920bd157 | 524 | else if (is_used_p (*t)) |
8c796c7c | 525 | unused = false; |
6ceec668 | 526 | else if (TREE_CODE (*t) == LABEL_DECL && TREE_USED (*t)) |
527 | /* For labels that are still used in the IL, the decision to | |
528 | preserve them must not depend DEBUG_INFO_LEVEL, otherwise we | |
529 | risk having different ordering in debug vs. non-debug builds | |
530 | during inlining or versioning. | |
531 | A label appearing here (we have already checked DECL_IGNORED_P) | |
532 | should not be used in the IL unless it has been explicitly used | |
533 | before, so we use TREE_USED as an approximation. */ | |
534 | /* In principle, we should do the same here as for the debug case | |
535 | below, however, when debugging, there might be additional nested | |
536 | levels that keep an upper level with a label live, so we have to | |
537 | force this block to be considered used, too. */ | |
538 | unused = false; | |
8c796c7c | 539 | |
540 | /* When we are not doing full debug info, we however can keep around | |
541 | only the used variables for cfgexpand's memory packing saving quite | |
48e1416a | 542 | a lot of memory. |
36267649 | 543 | |
544 | For sake of -g3, we keep around those vars but we don't count this as | |
545 | use of block, so innermost block with no used vars and no instructions | |
546 | can be considered dead. We only want to keep around blocks user can | |
48e1416a | 547 | breakpoint into and ask about value of optimized out variables. |
36267649 | 548 | |
29bcbc13 | 549 | Similarly we need to keep around types at least until all |
550 | variables of all nested blocks are gone. We track no | |
551 | information on whether given type is used or not, so we have | |
552 | to keep them even when not emitting debug information, | |
553 | otherwise we may end up remapping variables and their (local) | |
554 | types in different orders depending on whether debug | |
555 | information is being generated. */ | |
556 | ||
557 | else if (TREE_CODE (*t) == TYPE_DECL | |
558 | || debug_info_level == DINFO_LEVEL_NORMAL | |
45b2f957 | 559 | || debug_info_level == DINFO_LEVEL_VERBOSE) |
36267649 | 560 | ; |
7f481d3e | 561 | else |
8c796c7c | 562 | { |
1767a056 | 563 | *t = DECL_CHAIN (*t); |
8c796c7c | 564 | next = t; |
565 | } | |
566 | } | |
567 | ||
2ff2a12b | 568 | for (t = &BLOCK_SUBBLOCKS (scope); *t ;) |
920bd157 | 569 | if (remove_unused_scope_block_p (*t)) |
2ff2a12b | 570 | { |
571 | if (BLOCK_SUBBLOCKS (*t)) | |
572 | { | |
573 | tree next = BLOCK_CHAIN (*t); | |
574 | tree supercontext = BLOCK_SUPERCONTEXT (*t); | |
cee43f7e | 575 | |
2ff2a12b | 576 | *t = BLOCK_SUBBLOCKS (*t); |
cee43f7e | 577 | while (BLOCK_CHAIN (*t)) |
578 | { | |
579 | BLOCK_SUPERCONTEXT (*t) = supercontext; | |
580 | t = &BLOCK_CHAIN (*t); | |
581 | } | |
2ff2a12b | 582 | BLOCK_CHAIN (*t) = next; |
583 | BLOCK_SUPERCONTEXT (*t) = supercontext; | |
584 | t = &BLOCK_CHAIN (*t); | |
585 | nsubblocks ++; | |
586 | } | |
587 | else | |
36267649 | 588 | *t = BLOCK_CHAIN (*t); |
2ff2a12b | 589 | } |
590 | else | |
591 | { | |
592 | t = &BLOCK_CHAIN (*t); | |
593 | nsubblocks ++; | |
594 | } | |
cee43f7e | 595 | |
596 | ||
597 | if (!unused) | |
598 | ; | |
2ff2a12b | 599 | /* Outer scope is always used. */ |
cee43f7e | 600 | else if (!BLOCK_SUPERCONTEXT (scope) |
601 | || TREE_CODE (BLOCK_SUPERCONTEXT (scope)) == FUNCTION_DECL) | |
2ff2a12b | 602 | unused = false; |
cee43f7e | 603 | /* Innermost blocks with no live variables nor statements can be always |
604 | eliminated. */ | |
605 | else if (!nsubblocks) | |
606 | ; | |
7fa9fa16 | 607 | /* When not generating debug info we can eliminate info on unused |
608 | variables. */ | |
609 | else if (debug_info_level == DINFO_LEVEL_NONE) | |
f63d3ecc | 610 | { |
7fa9fa16 | 611 | /* Even for -g0 don't prune outer scopes from artificial |
f63d3ecc | 612 | functions, otherwise diagnostics using tree_nonartificial_location |
613 | will not be emitted properly. */ | |
614 | if (inlined_function_outer_scope_p (scope)) | |
615 | { | |
616 | tree ao = scope; | |
617 | ||
618 | while (ao | |
619 | && TREE_CODE (ao) == BLOCK | |
620 | && BLOCK_ABSTRACT_ORIGIN (ao) != ao) | |
621 | ao = BLOCK_ABSTRACT_ORIGIN (ao); | |
622 | if (ao | |
623 | && TREE_CODE (ao) == FUNCTION_DECL | |
624 | && DECL_DECLARED_INLINE_P (ao) | |
625 | && lookup_attribute ("artificial", DECL_ATTRIBUTES (ao))) | |
626 | unused = false; | |
627 | } | |
628 | } | |
4b5d70fd | 629 | else if (BLOCK_VARS (scope) || BLOCK_NUM_NONLOCALIZED_VARS (scope)) |
2ff2a12b | 630 | unused = false; |
cee43f7e | 631 | /* See if this block is important for representation of inlined function. |
632 | Inlined functions are always represented by block with | |
633 | block_ultimate_origin being set to FUNCTION_DECL and DECL_SOURCE_LOCATION | |
634 | set... */ | |
635 | else if (inlined_function_outer_scope_p (scope)) | |
636 | unused = false; | |
637 | else | |
638 | /* Verfify that only blocks with source location set | |
639 | are entry points to the inlined functions. */ | |
8e7408e3 | 640 | gcc_assert (LOCATION_LOCUS (BLOCK_SOURCE_LOCATION (scope)) |
641 | == UNKNOWN_LOCATION); | |
b26d0c9e | 642 | |
643 | TREE_USED (scope) = !unused; | |
2ff2a12b | 644 | return unused; |
645 | } | |
2d043327 | 646 | |
48e1416a | 647 | /* Mark all VAR_DECLS under *EXPR_P as used, so that they won't be |
280450fa | 648 | eliminated during the tree->rtl conversion process. */ |
649 | ||
650 | static inline void | |
920bd157 | 651 | mark_all_vars_used (tree *expr_p) |
280450fa | 652 | { |
920bd157 | 653 | walk_tree (expr_p, mark_all_vars_used_1, NULL, NULL); |
280450fa | 654 | } |
655 | ||
5169661d | 656 | /* Helper function for clear_unused_block_pointer, called via walk_tree. */ |
657 | ||
658 | static tree | |
659 | clear_unused_block_pointer_1 (tree *tp, int *, void *) | |
660 | { | |
661 | if (EXPR_P (*tp) && TREE_BLOCK (*tp) | |
662 | && !TREE_USED (TREE_BLOCK (*tp))) | |
663 | TREE_SET_BLOCK (*tp, NULL); | |
5169661d | 664 | return NULL_TREE; |
665 | } | |
666 | ||
9f559b20 | 667 | /* Set all block pointer in debug or clobber stmt to NULL if the block |
668 | is unused, so that they will not be streamed out. */ | |
5169661d | 669 | |
670 | static void | |
f1ff4562 | 671 | clear_unused_block_pointer (void) |
5169661d | 672 | { |
673 | basic_block bb; | |
674 | gimple_stmt_iterator gsi; | |
1aa7a266 | 675 | |
5169661d | 676 | FOR_EACH_BB (bb) |
677 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
678 | { | |
679 | unsigned i; | |
680 | tree b; | |
681 | gimple stmt = gsi_stmt (gsi); | |
682 | ||
9f559b20 | 683 | if (!is_gimple_debug (stmt) && !gimple_clobber_p (stmt)) |
5169661d | 684 | continue; |
685 | b = gimple_block (stmt); | |
686 | if (b && !TREE_USED (b)) | |
687 | gimple_set_block (stmt, NULL); | |
688 | for (i = 0; i < gimple_num_ops (stmt); i++) | |
689 | walk_tree (gimple_op_ptr (stmt, i), clear_unused_block_pointer_1, | |
690 | NULL, NULL); | |
691 | } | |
692 | } | |
b79917fd | 693 | |
694 | /* Dump scope blocks starting at SCOPE to FILE. INDENT is the | |
695 | indentation level and FLAGS is as in print_generic_expr. */ | |
36267649 | 696 | |
697 | static void | |
698 | dump_scope_block (FILE *file, int indent, tree scope, int flags) | |
699 | { | |
700 | tree var, t; | |
4b5d70fd | 701 | unsigned int i; |
36267649 | 702 | |
cee43f7e | 703 | fprintf (file, "\n%*s{ Scope block #%i%s%s",indent, "" , BLOCK_NUMBER (scope), |
704 | TREE_USED (scope) ? "" : " (unused)", | |
705 | BLOCK_ABSTRACT (scope) ? " (abstract)": ""); | |
8e7408e3 | 706 | if (LOCATION_LOCUS (BLOCK_SOURCE_LOCATION (scope)) != UNKNOWN_LOCATION) |
cee43f7e | 707 | { |
708 | expanded_location s = expand_location (BLOCK_SOURCE_LOCATION (scope)); | |
709 | fprintf (file, " %s:%i", s.file, s.line); | |
710 | } | |
711 | if (BLOCK_ABSTRACT_ORIGIN (scope)) | |
36267649 | 712 | { |
cee43f7e | 713 | tree origin = block_ultimate_origin (scope); |
714 | if (origin) | |
715 | { | |
716 | fprintf (file, " Originating from :"); | |
717 | if (DECL_P (origin)) | |
718 | print_generic_decl (file, origin, flags); | |
719 | else | |
720 | fprintf (file, "#%i", BLOCK_NUMBER (origin)); | |
721 | } | |
36267649 | 722 | } |
cee43f7e | 723 | fprintf (file, " \n"); |
1767a056 | 724 | for (var = BLOCK_VARS (scope); var; var = DECL_CHAIN (var)) |
36267649 | 725 | { |
f665f7bb | 726 | fprintf (file, "%*s", indent, ""); |
36267649 | 727 | print_generic_decl (file, var, flags); |
4ae5778c | 728 | fprintf (file, "\n"); |
36267649 | 729 | } |
4b5d70fd | 730 | for (i = 0; i < BLOCK_NUM_NONLOCALIZED_VARS (scope); i++) |
731 | { | |
732 | fprintf (file, "%*s",indent, ""); | |
733 | print_generic_decl (file, BLOCK_NONLOCALIZED_VAR (scope, i), | |
734 | flags); | |
735 | fprintf (file, " (nonlocalized)\n"); | |
736 | } | |
36267649 | 737 | for (t = BLOCK_SUBBLOCKS (scope); t ; t = BLOCK_CHAIN (t)) |
738 | dump_scope_block (file, indent + 2, t, flags); | |
cee43f7e | 739 | fprintf (file, "\n%*s}\n",indent, ""); |
36267649 | 740 | } |
741 | ||
7496b609 | 742 | /* Dump the tree of lexical scopes starting at SCOPE to stderr. FLAGS |
743 | is as in print_generic_expr. */ | |
744 | ||
4b987fac | 745 | DEBUG_FUNCTION void |
7496b609 | 746 | debug_scope_block (tree scope, int flags) |
747 | { | |
748 | dump_scope_block (stderr, 0, scope, flags); | |
749 | } | |
750 | ||
b79917fd | 751 | |
752 | /* Dump the tree of lexical scopes of current_function_decl to FILE. | |
753 | FLAGS is as in print_generic_expr. */ | |
754 | ||
cee43f7e | 755 | void |
756 | dump_scope_blocks (FILE *file, int flags) | |
757 | { | |
758 | dump_scope_block (file, 0, DECL_INITIAL (current_function_decl), flags); | |
759 | } | |
db22d3cc | 760 | |
b79917fd | 761 | |
762 | /* Dump the tree of lexical scopes of current_function_decl to stderr. | |
763 | FLAGS is as in print_generic_expr. */ | |
764 | ||
4b987fac | 765 | DEBUG_FUNCTION void |
b79917fd | 766 | debug_scope_blocks (int flags) |
767 | { | |
768 | dump_scope_blocks (stderr, flags); | |
769 | } | |
770 | ||
db22d3cc | 771 | /* Remove local variables that are not referenced in the IL. */ |
772 | ||
773 | void | |
774 | remove_unused_locals (void) | |
775 | { | |
776 | basic_block bb; | |
b03e5397 | 777 | tree var; |
920bd157 | 778 | unsigned srcidx, dstidx, num; |
3c25489e | 779 | bool have_local_clobbers = false; |
db22d3cc | 780 | |
fe5c69b7 | 781 | /* Removing declarations from lexical blocks when not optimizing is |
782 | not only a waste of time, it actually causes differences in stack | |
783 | layout. */ | |
784 | if (!optimize) | |
785 | return; | |
786 | ||
4b366dd3 | 787 | timevar_push (TV_REMOVE_UNUSED); |
788 | ||
36267649 | 789 | mark_scope_block_unused (DECL_INITIAL (current_function_decl)); |
75a70cf9 | 790 | |
4ae5778c | 791 | usedvars = BITMAP_ALLOC (NULL); |
db22d3cc | 792 | |
793 | /* Walk the CFG marking all referenced symbols. */ | |
794 | FOR_EACH_BB (bb) | |
795 | { | |
75a70cf9 | 796 | gimple_stmt_iterator gsi; |
797 | size_t i; | |
32dedf8f | 798 | edge_iterator ei; |
799 | edge e; | |
db22d3cc | 800 | |
801 | /* Walk the statements. */ | |
75a70cf9 | 802 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
803 | { | |
804 | gimple stmt = gsi_stmt (gsi); | |
805 | tree b = gimple_block (stmt); | |
806 | ||
9845d120 | 807 | if (is_gimple_debug (stmt)) |
808 | continue; | |
809 | ||
3c25489e | 810 | if (gimple_clobber_p (stmt)) |
811 | { | |
812 | have_local_clobbers = true; | |
813 | continue; | |
814 | } | |
815 | ||
75a70cf9 | 816 | if (b) |
817 | TREE_USED (b) = true; | |
db22d3cc | 818 | |
75a70cf9 | 819 | for (i = 0; i < gimple_num_ops (stmt); i++) |
920bd157 | 820 | mark_all_vars_used (gimple_op_ptr (gsi_stmt (gsi), i)); |
75a70cf9 | 821 | } |
822 | ||
823 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
db22d3cc | 824 | { |
825 | use_operand_p arg_p; | |
826 | ssa_op_iter i; | |
75a70cf9 | 827 | tree def; |
828 | gimple phi = gsi_stmt (gsi); | |
db22d3cc | 829 | |
7c782c9b | 830 | if (virtual_operand_p (gimple_phi_result (phi))) |
db22d3cc | 831 | continue; |
832 | ||
75a70cf9 | 833 | def = gimple_phi_result (phi); |
920bd157 | 834 | mark_all_vars_used (&def); |
db22d3cc | 835 | |
836 | FOR_EACH_PHI_ARG (arg_p, phi, i, SSA_OP_ALL_USES) | |
837 | { | |
838 | tree arg = USE_FROM_PTR (arg_p); | |
5169661d | 839 | int index = PHI_ARG_INDEX_FROM_USE (arg_p); |
840 | tree block = | |
841 | LOCATION_BLOCK (gimple_phi_arg_location (phi, index)); | |
842 | if (block != NULL) | |
843 | TREE_USED (block) = true; | |
920bd157 | 844 | mark_all_vars_used (&arg); |
db22d3cc | 845 | } |
846 | } | |
32dedf8f | 847 | |
848 | FOR_EACH_EDGE (e, ei, bb->succs) | |
f1ff4562 | 849 | if (LOCATION_BLOCK (e->goto_locus) != NULL) |
5169661d | 850 | TREE_USED (LOCATION_BLOCK (e->goto_locus)) = true; |
db22d3cc | 851 | } |
852 | ||
3c25489e | 853 | /* We do a two-pass approach about the out-of-scope clobbers. We want |
854 | to remove them if they are the only references to a local variable, | |
855 | but we want to retain them when there's any other. So the first pass | |
856 | ignores them, and the second pass (if there were any) tries to remove | |
857 | them. */ | |
858 | if (have_local_clobbers) | |
859 | FOR_EACH_BB (bb) | |
860 | { | |
861 | gimple_stmt_iterator gsi; | |
862 | ||
863 | for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi);) | |
864 | { | |
865 | gimple stmt = gsi_stmt (gsi); | |
866 | tree b = gimple_block (stmt); | |
867 | ||
868 | if (gimple_clobber_p (stmt)) | |
869 | { | |
870 | tree lhs = gimple_assign_lhs (stmt); | |
9f559b20 | 871 | tree base = get_base_address (lhs); |
872 | /* Remove clobbers referencing unused vars, or clobbers | |
873 | with MEM_REF lhs referencing uninitialized pointers. */ | |
874 | if ((TREE_CODE (base) == VAR_DECL && !is_used_p (base)) | |
875 | || (TREE_CODE (lhs) == MEM_REF | |
876 | && TREE_CODE (TREE_OPERAND (lhs, 0)) == SSA_NAME | |
877 | && SSA_NAME_IS_DEFAULT_DEF (TREE_OPERAND (lhs, 0)) | |
878 | && (TREE_CODE (SSA_NAME_VAR (TREE_OPERAND (lhs, 0))) | |
879 | != PARM_DECL))) | |
3c25489e | 880 | { |
881 | unlink_stmt_vdef (stmt); | |
882 | gsi_remove (&gsi, true); | |
883 | release_defs (stmt); | |
884 | continue; | |
885 | } | |
886 | if (b) | |
887 | TREE_USED (b) = true; | |
888 | } | |
889 | gsi_next (&gsi); | |
890 | } | |
891 | } | |
892 | ||
e15deb4b | 893 | cfun->has_local_explicit_reg_vars = false; |
894 | ||
920bd157 | 895 | /* Remove unmarked local and global vars from local_decls. */ |
f1f41a6c | 896 | num = vec_safe_length (cfun->local_decls); |
501bdd19 | 897 | for (srcidx = 0, dstidx = 0; srcidx < num; srcidx++) |
db22d3cc | 898 | { |
f1f41a6c | 899 | var = (*cfun->local_decls)[srcidx]; |
ad75582e | 900 | if (TREE_CODE (var) == VAR_DECL) |
db22d3cc | 901 | { |
920bd157 | 902 | if (!is_used_p (var)) |
ad75582e | 903 | { |
1ba198c0 | 904 | tree def; |
7843e4bc | 905 | if (cfun->nonlocal_goto_save_area |
906 | && TREE_OPERAND (cfun->nonlocal_goto_save_area, 0) == var) | |
907 | cfun->nonlocal_goto_save_area = NULL; | |
1ba198c0 | 908 | /* Release any default def associated with var. */ |
909 | if ((def = ssa_default_def (cfun, var)) != NULL_TREE) | |
910 | { | |
911 | set_ssa_default_def (cfun, var, NULL_TREE); | |
912 | release_ssa_name (def); | |
913 | } | |
ad75582e | 914 | continue; |
a93b21ea | 915 | } |
db22d3cc | 916 | } |
ad75582e | 917 | if (TREE_CODE (var) == VAR_DECL |
918 | && DECL_HARD_REGISTER (var) | |
919 | && !is_global_var (var)) | |
e15deb4b | 920 | cfun->has_local_explicit_reg_vars = true; |
2ab2ce89 | 921 | |
501bdd19 | 922 | if (srcidx != dstidx) |
f1f41a6c | 923 | (*cfun->local_decls)[dstidx] = var; |
501bdd19 | 924 | dstidx++; |
db22d3cc | 925 | } |
501bdd19 | 926 | if (dstidx != num) |
560965e9 | 927 | { |
928 | statistics_counter_event (cfun, "unused VAR_DECLs removed", num - dstidx); | |
929 | cfun->local_decls->truncate (dstidx); | |
930 | } | |
2887c015 | 931 | |
920bd157 | 932 | remove_unused_scope_block_p (DECL_INITIAL (current_function_decl)); |
5169661d | 933 | clear_unused_block_pointer (); |
2887c015 | 934 | |
4ae5778c | 935 | BITMAP_FREE (usedvars); |
fe15b701 | 936 | |
36267649 | 937 | if (dump_file && (dump_flags & TDF_DETAILS)) |
938 | { | |
939 | fprintf (dump_file, "Scope blocks after cleanups:\n"); | |
cee43f7e | 940 | dump_scope_blocks (dump_file, dump_flags); |
36267649 | 941 | } |
4b366dd3 | 942 | |
943 | timevar_pop (TV_REMOVE_UNUSED); | |
db22d3cc | 944 | } |
945 | ||
4fb07d00 | 946 | /* Obstack for globale liveness info bitmaps. We don't want to put these |
947 | on the default obstack because these bitmaps can grow quite large and | |
948 | we'll hold on to all that memory until the end of the compiler run. | |
949 | As a bonus, delete_tree_live_info can destroy all the bitmaps by just | |
950 | releasing the whole obstack. */ | |
951 | static bitmap_obstack liveness_bitmap_obstack; | |
4ee9c684 | 952 | |
953 | /* Allocate and return a new live range information object base on MAP. */ | |
954 | ||
955 | static tree_live_info_p | |
956 | new_tree_live_info (var_map map) | |
957 | { | |
958 | tree_live_info_p live; | |
4fb07d00 | 959 | basic_block bb; |
4ee9c684 | 960 | |
4fb07d00 | 961 | live = XNEW (struct tree_live_info_d); |
4ee9c684 | 962 | live->map = map; |
fe672ac0 | 963 | live->num_blocks = last_basic_block_for_fn (cfun); |
4ee9c684 | 964 | |
fe672ac0 | 965 | live->livein = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
4fb07d00 | 966 | FOR_EACH_BB (bb) |
967 | bitmap_initialize (&live->livein[bb->index], &liveness_bitmap_obstack); | |
4ee9c684 | 968 | |
fe672ac0 | 969 | live->liveout = XNEWVEC (bitmap_head, last_basic_block_for_fn (cfun)); |
4fb07d00 | 970 | FOR_EACH_BB (bb) |
971 | bitmap_initialize (&live->liveout[bb->index], &liveness_bitmap_obstack); | |
30928c44 | 972 | |
fe672ac0 | 973 | live->work_stack = XNEWVEC (int, last_basic_block_for_fn (cfun)); |
30928c44 | 974 | live->stack_top = live->work_stack; |
975 | ||
4fb07d00 | 976 | live->global = BITMAP_ALLOC (&liveness_bitmap_obstack); |
4ee9c684 | 977 | return live; |
978 | } | |
979 | ||
980 | ||
981 | /* Free storage for live range info object LIVE. */ | |
982 | ||
48e1416a | 983 | void |
4ee9c684 | 984 | delete_tree_live_info (tree_live_info_p live) |
985 | { | |
4fb07d00 | 986 | bitmap_obstack_release (&liveness_bitmap_obstack); |
30928c44 | 987 | free (live->work_stack); |
30928c44 | 988 | free (live->liveout); |
30928c44 | 989 | free (live->livein); |
30928c44 | 990 | free (live); |
4ee9c684 | 991 | } |
992 | ||
993 | ||
48e1416a | 994 | /* Visit basic block BB and propagate any required live on entry bits from |
995 | LIVE into the predecessors. VISITED is the bitmap of visited blocks. | |
7920eed5 | 996 | TMP is a temporary work bitmap which is passed in to avoid reallocating |
30928c44 | 997 | it each time. */ |
4ee9c684 | 998 | |
48e1416a | 999 | static void |
30928c44 | 1000 | loe_visit_block (tree_live_info_p live, basic_block bb, sbitmap visited, |
1001 | bitmap tmp) | |
4ee9c684 | 1002 | { |
30928c44 | 1003 | edge e; |
1004 | bool change; | |
1005 | edge_iterator ei; | |
1006 | basic_block pred_bb; | |
1007 | bitmap loe; | |
4ee9c684 | 1008 | |
688425e8 | 1009 | gcc_checking_assert (!bitmap_bit_p (visited, bb->index)); |
08b7917c | 1010 | bitmap_set_bit (visited, bb->index); |
688425e8 | 1011 | |
30928c44 | 1012 | loe = live_on_entry (live, bb); |
4ee9c684 | 1013 | |
30928c44 | 1014 | FOR_EACH_EDGE (e, ei, bb->preds) |
4ee9c684 | 1015 | { |
30928c44 | 1016 | pred_bb = e->src; |
34154e27 | 1017 | if (pred_bb == ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
30928c44 | 1018 | continue; |
2d043327 | 1019 | /* TMP is variables live-on-entry from BB that aren't defined in the |
48e1416a | 1020 | predecessor block. This should be the live on entry vars to pred. |
30928c44 | 1021 | Note that liveout is the DEFs in a block while live on entry is |
1022 | being calculated. */ | |
4fb07d00 | 1023 | bitmap_and_compl (tmp, loe, &live->liveout[pred_bb->index]); |
30928c44 | 1024 | |
48e1416a | 1025 | /* Add these bits to live-on-entry for the pred. if there are any |
30928c44 | 1026 | changes, and pred_bb has been visited already, add it to the |
1027 | revisit stack. */ | |
1028 | change = bitmap_ior_into (live_on_entry (live, pred_bb), tmp); | |
08b7917c | 1029 | if (bitmap_bit_p (visited, pred_bb->index) && change) |
30928c44 | 1030 | { |
08b7917c | 1031 | bitmap_clear_bit (visited, pred_bb->index); |
30928c44 | 1032 | *(live->stack_top)++ = pred_bb->index; |
1033 | } | |
4ee9c684 | 1034 | } |
1035 | } | |
1036 | ||
1037 | ||
48e1416a | 1038 | /* Using LIVE, fill in all the live-on-entry blocks between the defs and uses |
7920eed5 | 1039 | of all the variables. */ |
4ee9c684 | 1040 | |
30928c44 | 1041 | static void |
1042 | live_worklist (tree_live_info_p live) | |
4ee9c684 | 1043 | { |
30928c44 | 1044 | unsigned b; |
4ee9c684 | 1045 | basic_block bb; |
fe672ac0 | 1046 | sbitmap visited = sbitmap_alloc (last_basic_block_for_fn (cfun) + 1); |
4fb07d00 | 1047 | bitmap tmp = BITMAP_ALLOC (&liveness_bitmap_obstack); |
4ee9c684 | 1048 | |
53c5d9d4 | 1049 | bitmap_clear (visited); |
4ee9c684 | 1050 | |
80777cd8 | 1051 | /* Visit all the blocks in reverse order and propagate live on entry values |
30928c44 | 1052 | into the predecessors blocks. */ |
1053 | FOR_EACH_BB_REVERSE (bb) | |
1054 | loe_visit_block (live, bb, visited, tmp); | |
4ee9c684 | 1055 | |
30928c44 | 1056 | /* Process any blocks which require further iteration. */ |
1057 | while (live->stack_top != live->work_stack) | |
4ee9c684 | 1058 | { |
30928c44 | 1059 | b = *--(live->stack_top); |
f5a6b05f | 1060 | loe_visit_block (live, BASIC_BLOCK_FOR_FN (cfun, b), visited, tmp); |
30928c44 | 1061 | } |
4ee9c684 | 1062 | |
30928c44 | 1063 | BITMAP_FREE (tmp); |
1064 | sbitmap_free (visited); | |
1065 | } | |
4ee9c684 | 1066 | |
4ee9c684 | 1067 | |
7920eed5 | 1068 | /* Calculate the initial live on entry vector for SSA_NAME using immediate_use |
30928c44 | 1069 | links. Set the live on entry fields in LIVE. Def's are marked temporarily |
1070 | in the liveout vector. */ | |
4ee9c684 | 1071 | |
30928c44 | 1072 | static void |
1073 | set_var_live_on_entry (tree ssa_name, tree_live_info_p live) | |
1074 | { | |
1075 | int p; | |
75a70cf9 | 1076 | gimple stmt; |
30928c44 | 1077 | use_operand_p use; |
1078 | basic_block def_bb = NULL; | |
1079 | imm_use_iterator imm_iter; | |
1080 | bool global = false; | |
4ee9c684 | 1081 | |
30928c44 | 1082 | p = var_to_partition (live->map, ssa_name); |
1083 | if (p == NO_PARTITION) | |
1084 | return; | |
4ee9c684 | 1085 | |
30928c44 | 1086 | stmt = SSA_NAME_DEF_STMT (ssa_name); |
1087 | if (stmt) | |
4ee9c684 | 1088 | { |
75a70cf9 | 1089 | def_bb = gimple_bb (stmt); |
2d043327 | 1090 | /* Mark defs in liveout bitmap temporarily. */ |
30928c44 | 1091 | if (def_bb) |
4fb07d00 | 1092 | bitmap_set_bit (&live->liveout[def_bb->index], p); |
0cc4271a | 1093 | } |
30928c44 | 1094 | else |
34154e27 | 1095 | def_bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
4ee9c684 | 1096 | |
30928c44 | 1097 | /* Visit each use of SSA_NAME and if it isn't in the same block as the def, |
1098 | add it to the list of live on entry blocks. */ | |
1099 | FOR_EACH_IMM_USE_FAST (use, imm_iter, ssa_name) | |
4ee9c684 | 1100 | { |
75a70cf9 | 1101 | gimple use_stmt = USE_STMT (use); |
30928c44 | 1102 | basic_block add_block = NULL; |
4ee9c684 | 1103 | |
75a70cf9 | 1104 | if (gimple_code (use_stmt) == GIMPLE_PHI) |
30928c44 | 1105 | { |
1106 | /* Uses in PHI's are considered to be live at exit of the SRC block | |
1107 | as this is where a copy would be inserted. Check to see if it is | |
1108 | defined in that block, or whether its live on entry. */ | |
1109 | int index = PHI_ARG_INDEX_FROM_USE (use); | |
75a70cf9 | 1110 | edge e = gimple_phi_arg_edge (use_stmt, index); |
34154e27 | 1111 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
4ee9c684 | 1112 | { |
30928c44 | 1113 | if (e->src != def_bb) |
1114 | add_block = e->src; | |
4ee9c684 | 1115 | } |
30928c44 | 1116 | } |
9845d120 | 1117 | else if (is_gimple_debug (use_stmt)) |
1118 | continue; | |
30928c44 | 1119 | else |
1120 | { | |
1121 | /* If its not defined in this block, its live on entry. */ | |
75a70cf9 | 1122 | basic_block use_bb = gimple_bb (use_stmt); |
30928c44 | 1123 | if (use_bb != def_bb) |
1124 | add_block = use_bb; | |
48e1416a | 1125 | } |
30928c44 | 1126 | |
1127 | /* If there was a live on entry use, set the bit. */ | |
1128 | if (add_block) | |
1129 | { | |
1130 | global = true; | |
4fb07d00 | 1131 | bitmap_set_bit (&live->livein[add_block->index], p); |
4ee9c684 | 1132 | } |
1133 | } | |
4ee9c684 | 1134 | |
30928c44 | 1135 | /* If SSA_NAME is live on entry to at least one block, fill in all the live |
1136 | on entry blocks between the def and all the uses. */ | |
1137 | if (global) | |
1138 | bitmap_set_bit (live->global, p); | |
4ee9c684 | 1139 | } |
1140 | ||
1141 | ||
1142 | /* Calculate the live on exit vectors based on the entry info in LIVEINFO. */ | |
1143 | ||
1144 | void | |
1145 | calculate_live_on_exit (tree_live_info_p liveinfo) | |
1146 | { | |
4ee9c684 | 1147 | basic_block bb; |
1148 | edge e; | |
30928c44 | 1149 | edge_iterator ei; |
4ee9c684 | 1150 | |
2d043327 | 1151 | /* live on entry calculations used liveout vectors for defs, clear them. */ |
30928c44 | 1152 | FOR_EACH_BB (bb) |
4fb07d00 | 1153 | bitmap_clear (&liveinfo->liveout[bb->index]); |
4ee9c684 | 1154 | |
1155 | /* Set all the live-on-exit bits for uses in PHIs. */ | |
1156 | FOR_EACH_BB (bb) | |
1157 | { | |
75a70cf9 | 1158 | gimple_stmt_iterator gsi; |
1159 | size_t i; | |
1160 | ||
30928c44 | 1161 | /* Mark the PHI arguments which are live on exit to the pred block. */ |
75a70cf9 | 1162 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
1163 | { | |
1164 | gimple phi = gsi_stmt (gsi); | |
1165 | for (i = 0; i < gimple_phi_num_args (phi); i++) | |
48e1416a | 1166 | { |
75a70cf9 | 1167 | tree t = PHI_ARG_DEF (phi, i); |
1168 | int p; | |
1169 | ||
1170 | if (TREE_CODE (t) != SSA_NAME) | |
1171 | continue; | |
1172 | ||
1173 | p = var_to_partition (liveinfo->map, t); | |
1174 | if (p == NO_PARTITION) | |
1175 | continue; | |
1176 | e = gimple_phi_arg_edge (phi, i); | |
34154e27 | 1177 | if (e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun)) |
4fb07d00 | 1178 | bitmap_set_bit (&liveinfo->liveout[e->src->index], p); |
75a70cf9 | 1179 | } |
1180 | } | |
30928c44 | 1181 | |
2d043327 | 1182 | /* Add each successors live on entry to this bock live on exit. */ |
30928c44 | 1183 | FOR_EACH_EDGE (e, ei, bb->succs) |
34154e27 | 1184 | if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun)) |
4fb07d00 | 1185 | bitmap_ior_into (&liveinfo->liveout[bb->index], |
30928c44 | 1186 | live_on_entry (liveinfo, e->dest)); |
4ee9c684 | 1187 | } |
30928c44 | 1188 | } |
1189 | ||
2d043327 | 1190 | |
48e1416a | 1191 | /* Given partition map MAP, calculate all the live on entry bitmaps for |
30928c44 | 1192 | each partition. Return a new live info object. */ |
1193 | ||
48e1416a | 1194 | tree_live_info_p |
30928c44 | 1195 | calculate_live_ranges (var_map map) |
1196 | { | |
1197 | tree var; | |
1198 | unsigned i; | |
1199 | tree_live_info_p live; | |
4ee9c684 | 1200 | |
4fb07d00 | 1201 | bitmap_obstack_initialize (&liveness_bitmap_obstack); |
30928c44 | 1202 | live = new_tree_live_info (map); |
4ee9c684 | 1203 | for (i = 0; i < num_var_partitions (map); i++) |
1204 | { | |
30928c44 | 1205 | var = partition_to_var (map, i); |
1206 | if (var != NULL_TREE) | |
1207 | set_var_live_on_entry (var, live); | |
4ee9c684 | 1208 | } |
1209 | ||
30928c44 | 1210 | live_worklist (live); |
1211 | ||
1212 | #ifdef ENABLE_CHECKING | |
1213 | verify_live_on_entry (live); | |
1214 | #endif | |
1215 | ||
1216 | calculate_live_on_exit (live); | |
1217 | return live; | |
4ee9c684 | 1218 | } |
1219 | ||
1220 | ||
4ee9c684 | 1221 | /* Output partition map MAP to file F. */ |
1222 | ||
1223 | void | |
1224 | dump_var_map (FILE *f, var_map map) | |
1225 | { | |
1226 | int t; | |
1227 | unsigned x, y; | |
1228 | int p; | |
1229 | ||
1230 | fprintf (f, "\nPartition map \n\n"); | |
1231 | ||
1232 | for (x = 0; x < map->num_partitions; x++) | |
1233 | { | |
2d043327 | 1234 | if (map->view_to_partition != NULL) |
1235 | p = map->view_to_partition[x]; | |
4ee9c684 | 1236 | else |
1237 | p = x; | |
1238 | ||
ade7d11b | 1239 | if (ssa_name (p) == NULL_TREE |
1240 | || virtual_operand_p (ssa_name (p))) | |
4ee9c684 | 1241 | continue; |
1242 | ||
1243 | t = 0; | |
c211d998 | 1244 | for (y = 1; y < num_ssa_names; y++) |
4ee9c684 | 1245 | { |
1246 | p = partition_find (map->var_partition, y); | |
2d043327 | 1247 | if (map->partition_to_view) |
1248 | p = map->partition_to_view[p]; | |
4ee9c684 | 1249 | if (p == (int)x) |
1250 | { | |
1251 | if (t++ == 0) | |
1252 | { | |
9af5ce0c | 1253 | fprintf (f, "Partition %d (", x); |
4ee9c684 | 1254 | print_generic_expr (f, partition_to_var (map, p), TDF_SLIM); |
1255 | fprintf (f, " - "); | |
1256 | } | |
1257 | fprintf (f, "%d ", y); | |
1258 | } | |
1259 | } | |
1260 | if (t != 0) | |
1261 | fprintf (f, ")\n"); | |
1262 | } | |
1263 | fprintf (f, "\n"); | |
1264 | } | |
1265 | ||
1266 | ||
c7d89805 | 1267 | /* Generic dump for the above. */ |
1268 | ||
1269 | DEBUG_FUNCTION void | |
1270 | debug (_var_map &ref) | |
1271 | { | |
1272 | dump_var_map (stderr, &ref); | |
1273 | } | |
1274 | ||
1275 | DEBUG_FUNCTION void | |
1276 | debug (_var_map *ptr) | |
1277 | { | |
1278 | if (ptr) | |
1279 | debug (*ptr); | |
1280 | else | |
1281 | fprintf (stderr, "<nil>\n"); | |
1282 | } | |
1283 | ||
1284 | ||
4ee9c684 | 1285 | /* Output live range info LIVE to file F, controlled by FLAG. */ |
1286 | ||
1287 | void | |
1288 | dump_live_info (FILE *f, tree_live_info_p live, int flag) | |
1289 | { | |
1290 | basic_block bb; | |
4f917ffe | 1291 | unsigned i; |
4ee9c684 | 1292 | var_map map = live->map; |
0cc4271a | 1293 | bitmap_iterator bi; |
4ee9c684 | 1294 | |
1295 | if ((flag & LIVEDUMP_ENTRY) && live->livein) | |
1296 | { | |
1297 | FOR_EACH_BB (bb) | |
1298 | { | |
1299 | fprintf (f, "\nLive on entry to BB%d : ", bb->index); | |
4fb07d00 | 1300 | EXECUTE_IF_SET_IN_BITMAP (&live->livein[bb->index], 0, i, bi) |
4ee9c684 | 1301 | { |
30928c44 | 1302 | print_generic_expr (f, partition_to_var (map, i), TDF_SLIM); |
1303 | fprintf (f, " "); | |
4ee9c684 | 1304 | } |
1305 | fprintf (f, "\n"); | |
1306 | } | |
1307 | } | |
1308 | ||
1309 | if ((flag & LIVEDUMP_EXIT) && live->liveout) | |
1310 | { | |
1311 | FOR_EACH_BB (bb) | |
1312 | { | |
1313 | fprintf (f, "\nLive on exit from BB%d : ", bb->index); | |
4fb07d00 | 1314 | EXECUTE_IF_SET_IN_BITMAP (&live->liveout[bb->index], 0, i, bi) |
4ee9c684 | 1315 | { |
1316 | print_generic_expr (f, partition_to_var (map, i), TDF_SLIM); | |
1317 | fprintf (f, " "); | |
0cc4271a | 1318 | } |
4ee9c684 | 1319 | fprintf (f, "\n"); |
1320 | } | |
1321 | } | |
1322 | } | |
8c0963c4 | 1323 | |
c7d89805 | 1324 | |
1325 | /* Generic dump for the above. */ | |
1326 | ||
1327 | DEBUG_FUNCTION void | |
1328 | debug (tree_live_info_d &ref) | |
1329 | { | |
1330 | dump_live_info (stderr, &ref, 0); | |
1331 | } | |
1332 | ||
1333 | DEBUG_FUNCTION void | |
1334 | debug (tree_live_info_d *ptr) | |
1335 | { | |
1336 | if (ptr) | |
1337 | debug (*ptr); | |
1338 | else | |
1339 | fprintf (stderr, "<nil>\n"); | |
1340 | } | |
1341 | ||
1342 | ||
8c0963c4 | 1343 | #ifdef ENABLE_CHECKING |
2d043327 | 1344 | /* Verify that SSA_VAR is a non-virtual SSA_NAME. */ |
1345 | ||
8c0963c4 | 1346 | void |
1347 | register_ssa_partition_check (tree ssa_var) | |
1348 | { | |
1349 | gcc_assert (TREE_CODE (ssa_var) == SSA_NAME); | |
7c782c9b | 1350 | if (virtual_operand_p (ssa_var)) |
8c0963c4 | 1351 | { |
1352 | fprintf (stderr, "Illegally registering a virtual SSA name :"); | |
1353 | print_generic_expr (stderr, ssa_var, TDF_SLIM); | |
1354 | fprintf (stderr, " in the SSA->Normal phase.\n"); | |
1355 | internal_error ("SSA corruption"); | |
1356 | } | |
1357 | } | |
30928c44 | 1358 | |
1359 | ||
1360 | /* Verify that the info in LIVE matches the current cfg. */ | |
2d043327 | 1361 | |
30928c44 | 1362 | static void |
1363 | verify_live_on_entry (tree_live_info_p live) | |
1364 | { | |
1365 | unsigned i; | |
1366 | tree var; | |
75a70cf9 | 1367 | gimple stmt; |
30928c44 | 1368 | basic_block bb; |
1369 | edge e; | |
1370 | int num; | |
1371 | edge_iterator ei; | |
1372 | var_map map = live->map; | |
1373 | ||
1374 | /* Check for live on entry partitions and report those with a DEF in | |
1375 | the program. This will typically mean an optimization has done | |
1376 | something wrong. */ | |
34154e27 | 1377 | bb = ENTRY_BLOCK_PTR_FOR_FN (cfun); |
30928c44 | 1378 | num = 0; |
1379 | FOR_EACH_EDGE (e, ei, bb->succs) | |
1380 | { | |
1381 | int entry_block = e->dest->index; | |
34154e27 | 1382 | if (e->dest == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
30928c44 | 1383 | continue; |
1384 | for (i = 0; i < (unsigned)num_var_partitions (map); i++) | |
1385 | { | |
1386 | basic_block tmp; | |
ec11736b | 1387 | tree d = NULL_TREE; |
30928c44 | 1388 | bitmap loe; |
1389 | var = partition_to_var (map, i); | |
1390 | stmt = SSA_NAME_DEF_STMT (var); | |
75a70cf9 | 1391 | tmp = gimple_bb (stmt); |
ec11736b | 1392 | if (SSA_NAME_VAR (var)) |
1393 | d = ssa_default_def (cfun, SSA_NAME_VAR (var)); | |
30928c44 | 1394 | |
1395 | loe = live_on_entry (live, e->dest); | |
1396 | if (loe && bitmap_bit_p (loe, i)) | |
1397 | { | |
75a70cf9 | 1398 | if (!gimple_nop_p (stmt)) |
30928c44 | 1399 | { |
1400 | num++; | |
1401 | print_generic_expr (stderr, var, TDF_SLIM); | |
1402 | fprintf (stderr, " is defined "); | |
1403 | if (tmp) | |
1404 | fprintf (stderr, " in BB%d, ", tmp->index); | |
1405 | fprintf (stderr, "by:\n"); | |
75a70cf9 | 1406 | print_gimple_stmt (stderr, stmt, 0, TDF_SLIM); |
48e1416a | 1407 | fprintf (stderr, "\nIt is also live-on-entry to entry BB %d", |
30928c44 | 1408 | entry_block); |
1409 | fprintf (stderr, " So it appears to have multiple defs.\n"); | |
1410 | } | |
1411 | else | |
1412 | { | |
1413 | if (d != var) | |
1414 | { | |
1415 | num++; | |
1416 | print_generic_expr (stderr, var, TDF_SLIM); | |
75a70cf9 | 1417 | fprintf (stderr, " is live-on-entry to BB%d ", |
1418 | entry_block); | |
30928c44 | 1419 | if (d) |
1420 | { | |
1421 | fprintf (stderr, " but is not the default def of "); | |
1422 | print_generic_expr (stderr, d, TDF_SLIM); | |
1423 | fprintf (stderr, "\n"); | |
1424 | } | |
1425 | else | |
1426 | fprintf (stderr, " and there is no default def.\n"); | |
1427 | } | |
1428 | } | |
1429 | } | |
1430 | else | |
1431 | if (d == var) | |
1432 | { | |
48e1416a | 1433 | /* The only way this var shouldn't be marked live on entry is |
30928c44 | 1434 | if it occurs in a PHI argument of the block. */ |
75a70cf9 | 1435 | size_t z; |
1436 | bool ok = false; | |
1437 | gimple_stmt_iterator gsi; | |
1438 | for (gsi = gsi_start_phis (e->dest); | |
1439 | !gsi_end_p (gsi) && !ok; | |
1440 | gsi_next (&gsi)) | |
30928c44 | 1441 | { |
75a70cf9 | 1442 | gimple phi = gsi_stmt (gsi); |
1443 | for (z = 0; z < gimple_phi_num_args (phi); z++) | |
1444 | if (var == gimple_phi_arg_def (phi, z)) | |
30928c44 | 1445 | { |
75a70cf9 | 1446 | ok = true; |
30928c44 | 1447 | break; |
1448 | } | |
1449 | } | |
1450 | if (ok) | |
1451 | continue; | |
1452 | num++; | |
1453 | print_generic_expr (stderr, var, TDF_SLIM); | |
48e1416a | 1454 | fprintf (stderr, " is not marked live-on-entry to entry BB%d ", |
30928c44 | 1455 | entry_block); |
1456 | fprintf (stderr, "but it is a default def so it should be.\n"); | |
1457 | } | |
1458 | } | |
1459 | } | |
1460 | gcc_assert (num <= 0); | |
1461 | } | |
8c0963c4 | 1462 | #endif |