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1 | /* Scanning of rtl for dataflow analysis. |
2 | Copyright (C) 2007 | |
3 | Free Software Foundation, Inc. | |
4 | Contributed by Kenneth Zadeck (zadeck@naturalbridge.com). | |
5 | ||
6 | This file is part of GCC. | |
7 | ||
8 | GCC is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 2, or (at your option) any later | |
11 | version. | |
12 | ||
13 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with GCC; see the file COPYING. If not, write to the Free | |
20 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA | |
21 | 02110-1301, USA. | |
22 | */ | |
23 | ||
24 | ||
25 | #include "config.h" | |
26 | #include "system.h" | |
27 | #include "coretypes.h" | |
28 | #include "tm.h" | |
29 | #include "rtl.h" | |
30 | #include "tm_p.h" | |
31 | #include "flags.h" | |
32 | #include "regs.h" | |
33 | #include "output.h" | |
34 | #include "except.h" | |
35 | #include "hard-reg-set.h" | |
36 | #include "basic-block.h" | |
37 | #include "timevar.h" | |
38 | #include "df.h" | |
39 | ||
40 | ||
41 | struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs; | |
42 | struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs; | |
43 | ||
44 | /*---------------------------------------------------------------------------- | |
45 | REG_N_SETS and REG_N_REFS. | |
46 | ----------------------------------------------------------------------------*/ | |
47 | ||
48 | /* If a pass need to change these values in some magical way or or the | |
49 | pass needs to have accurate values for these and is not using | |
50 | incremental df scanning, then it should use REG_N_SETS and | |
51 | REG_N_USES. If the pass is doing incremental scanning then it | |
52 | should be getting the info from DF_REG_DEF_COUNT and | |
53 | DF_REG_USE_COUNT. */ | |
54 | ||
55 | void | |
56 | regstat_init_n_sets_and_refs (void) | |
57 | { | |
58 | unsigned int i; | |
59 | unsigned int max_regno = max_reg_num (); | |
60 | ||
61 | timevar_push (TV_REG_STATS); | |
62 | df_grow_reg_info (); | |
63 | gcc_assert (!regstat_n_sets_and_refs); | |
64 | ||
65 | regstat_n_sets_and_refs = xmalloc (max_regno * sizeof (struct regstat_n_sets_and_refs_t)); | |
66 | ||
67 | for (i = 0; i < max_regno; i++) | |
68 | { | |
69 | SET_REG_N_SETS (i, DF_REG_DEF_COUNT (i)); | |
70 | SET_REG_N_REFS (i, DF_REG_USE_COUNT (i) + REG_N_SETS (i)); | |
71 | } | |
72 | timevar_pop (TV_REG_STATS); | |
73 | ||
74 | } | |
75 | ||
76 | ||
77 | /* Free the array that holds the REG_N_SETS and REG_N_REFS. */ | |
78 | ||
79 | void | |
80 | regstat_free_n_sets_and_refs (void) | |
81 | { | |
82 | gcc_assert (regstat_n_sets_and_refs); | |
83 | free (regstat_n_sets_and_refs); | |
84 | regstat_n_sets_and_refs = NULL; | |
85 | } | |
86 | ||
87 | ||
88 | /*---------------------------------------------------------------------------- | |
89 | REGISTER INFORMATION | |
90 | ||
91 | Process REG_N_DEATHS, REG_LIVE_LENGTH, REG_N_CALLS_CROSSED, | |
92 | REG_N_THROWING_CALLS_CROSSED and REG_BASIC_BLOCK. | |
93 | ||
94 | ----------------------------------------------------------------------------*/ | |
95 | ||
96 | static bitmap setjmp_crosses; | |
97 | struct reg_info_t *reg_info_p; | |
98 | ||
99 | /* The number allocated elements of reg_info_p. */ | |
100 | size_t reg_info_p_size; | |
101 | ||
102 | /* Compute register info: lifetime, bb, and number of defs and uses | |
103 | for basic block BB. The three bitvectors are scratch regs used | |
104 | here. */ | |
105 | ||
106 | static void | |
107 | regstat_bb_compute_ri (unsigned int bb_index, | |
108 | bitmap live, bitmap do_not_gen, bitmap artificial_uses, | |
109 | bitmap local_live, bitmap local_processed) | |
110 | { | |
111 | basic_block bb = BASIC_BLOCK (bb_index); | |
112 | rtx insn; | |
113 | struct df_ref **def_rec; | |
114 | struct df_ref **use_rec; | |
115 | int luid = 0; | |
116 | bitmap_iterator bi; | |
117 | unsigned int regno; | |
118 | ||
119 | bitmap_copy (live, df_get_live_out (bb)); | |
120 | bitmap_clear (artificial_uses); | |
121 | ||
122 | /* Process the regs live at the end of the block. Mark them as | |
123 | not local to any one basic block. */ | |
124 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) | |
125 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; | |
126 | ||
127 | /* Process the artificial defs and uses at the bottom of the block | |
128 | to begin processing. */ | |
129 | for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++) | |
130 | { | |
131 | struct df_ref *def = *def_rec; | |
132 | if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0) | |
133 | bitmap_clear_bit (live, DF_REF_REGNO (def)); | |
134 | } | |
135 | ||
136 | for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++) | |
137 | { | |
138 | struct df_ref *use = *use_rec; | |
139 | if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0) | |
140 | { | |
141 | regno = DF_REF_REGNO (use); | |
142 | bitmap_set_bit (live, regno); | |
143 | bitmap_set_bit (artificial_uses, regno); | |
144 | } | |
145 | } | |
146 | ||
147 | FOR_BB_INSNS_REVERSE (bb, insn) | |
148 | { | |
149 | unsigned int uid = INSN_UID (insn); | |
150 | unsigned int regno; | |
151 | bitmap_iterator bi; | |
152 | struct df_mw_hardreg **mws_rec; | |
153 | rtx link; | |
154 | ||
155 | if (!INSN_P (insn)) | |
156 | continue; | |
157 | ||
158 | /* Increment the live_length for all of the registers that | |
159 | are are referenced in this block and live at this | |
160 | particular point. */ | |
161 | EXECUTE_IF_SET_IN_BITMAP (local_live, 0, regno, bi) | |
162 | { | |
163 | REG_LIVE_LENGTH (regno)++; | |
164 | } | |
165 | luid++; | |
166 | ||
167 | bitmap_clear (do_not_gen); | |
168 | ||
169 | link = REG_NOTES (insn); | |
170 | while (link) | |
171 | { | |
172 | if (REG_NOTE_KIND (link) == REG_DEAD) | |
173 | REG_N_DEATHS(REGNO (XEXP (link, 0)))++; | |
174 | link = XEXP (link, 1); | |
175 | } | |
176 | ||
177 | /* Process the defs. */ | |
178 | if (CALL_P (insn)) | |
179 | { | |
180 | bool can_throw = can_throw_internal (insn); | |
181 | bool set_jump = (find_reg_note (insn, REG_SETJMP, NULL) != NULL); | |
182 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) | |
183 | { | |
184 | REG_N_CALLS_CROSSED (regno)++; | |
185 | if (can_throw) | |
186 | REG_N_THROWING_CALLS_CROSSED (regno)++; | |
187 | ||
188 | /* We have a problem with any pseudoreg that lives | |
189 | across the setjmp. ANSI says that if a user variable | |
190 | does not change in value between the setjmp and the | |
191 | longjmp, then the longjmp preserves it. This | |
192 | includes longjmp from a place where the pseudo | |
193 | appears dead. (In principle, the value still exists | |
194 | if it is in scope.) If the pseudo goes in a hard | |
195 | reg, some other value may occupy that hard reg where | |
196 | this pseudo is dead, thus clobbering the pseudo. | |
197 | Conclusion: such a pseudo must not go in a hard | |
198 | reg. */ | |
199 | if (set_jump) | |
200 | bitmap_set_bit (setjmp_crosses, regno); | |
201 | } | |
202 | } | |
203 | ||
204 | /* We only care about real sets for calls. Clobbers only | |
205 | may clobbers cannot be depended on. */ | |
206 | for (mws_rec = DF_INSN_UID_MWS (uid); *mws_rec; mws_rec++) | |
207 | { | |
208 | struct df_mw_hardreg *mws = *mws_rec; | |
209 | if (mws->type == DF_REF_REG_DEF) | |
210 | { | |
211 | bool all_dead = true; | |
212 | unsigned int r; | |
213 | ||
214 | for (r=mws->start_regno; r <= mws->end_regno; r++) | |
215 | if ((bitmap_bit_p (live, r)) | |
216 | || bitmap_bit_p (artificial_uses, r)) | |
217 | { | |
218 | all_dead = false; | |
219 | break; | |
220 | } | |
221 | ||
222 | if (all_dead) | |
223 | { | |
224 | unsigned int regno = mws->start_regno; | |
225 | bitmap_set_bit (do_not_gen, regno); | |
226 | /* Only do this if the value is totally dead. */ | |
227 | REG_LIVE_LENGTH (regno)++; | |
228 | } | |
229 | } | |
230 | } | |
231 | ||
232 | /* All of the defs except the return value are some sort of | |
233 | clobber. This code is for the return. */ | |
234 | for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++) | |
235 | { | |
236 | struct df_ref *def = *def_rec; | |
237 | if ((!CALL_P (insn)) | |
238 | || (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))) | |
239 | { | |
240 | unsigned int dregno = DF_REF_REGNO (def); | |
241 | ||
242 | if (bitmap_bit_p (live, dregno)) | |
243 | { | |
244 | /* If we have seen this regno, then it has already been | |
245 | processed correctly with the per insn increment. If we | |
246 | have not seen it we need to add the length from here to | |
247 | the end of the block to the live length. */ | |
248 | if (bitmap_bit_p (local_processed, dregno)) | |
249 | { | |
250 | if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) | |
251 | bitmap_clear_bit (local_live, dregno); | |
252 | } | |
253 | else | |
254 | { | |
255 | bitmap_set_bit (local_processed, dregno); | |
256 | REG_LIVE_LENGTH (dregno) += luid; | |
257 | } | |
258 | } | |
259 | else if ((!(DF_REF_FLAGS (def) & DF_REF_MW_HARDREG)) | |
260 | && (!bitmap_bit_p (artificial_uses, dregno))) | |
261 | { | |
262 | REG_LIVE_LENGTH (dregno)++; | |
263 | } | |
264 | ||
265 | if (dregno >= FIRST_PSEUDO_REGISTER) | |
266 | { | |
267 | REG_FREQ (dregno) += REG_FREQ_FROM_BB (bb); | |
268 | if (REG_BASIC_BLOCK (dregno) == REG_BLOCK_UNKNOWN) | |
269 | REG_BASIC_BLOCK (dregno) = bb->index; | |
270 | else if (REG_BASIC_BLOCK (dregno) != bb->index) | |
271 | REG_BASIC_BLOCK (dregno) = REG_BLOCK_GLOBAL; | |
272 | } | |
273 | ||
274 | if (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER + DF_REF_MAY_CLOBBER))) | |
275 | bitmap_set_bit (do_not_gen, dregno); | |
276 | ||
277 | /* Kill this register if it is not a subreg store or conditional store. */ | |
278 | if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) | |
279 | bitmap_clear_bit (live, dregno); | |
280 | } | |
281 | } | |
282 | ||
283 | for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++) | |
284 | { | |
285 | struct df_ref *use = *use_rec; | |
286 | unsigned int uregno = DF_REF_REGNO (use); | |
287 | ||
288 | if (uregno >= FIRST_PSEUDO_REGISTER) | |
289 | { | |
290 | REG_FREQ (uregno) += REG_FREQ_FROM_BB (bb); | |
291 | if (REG_BASIC_BLOCK (uregno) == REG_BLOCK_UNKNOWN) | |
292 | REG_BASIC_BLOCK (uregno) = bb->index; | |
293 | else if (REG_BASIC_BLOCK (uregno) != bb->index) | |
294 | REG_BASIC_BLOCK (uregno) = REG_BLOCK_GLOBAL; | |
295 | } | |
296 | ||
297 | if (!bitmap_bit_p (live, uregno)) | |
298 | { | |
299 | /* This register is now live. */ | |
300 | bitmap_set_bit (live, uregno); | |
301 | ||
302 | /* If we have seen this regno, then it has already been | |
303 | processed correctly with the per insn increment. If | |
304 | we have not seen it we set the bit so that begins to | |
305 | get processed locally. Note that we don't even get | |
306 | here if the variable was live at the end of the block | |
307 | since just a ref inside the block does not effect the | |
308 | calculations. */ | |
309 | REG_LIVE_LENGTH (uregno) ++; | |
310 | bitmap_set_bit (local_live, uregno); | |
311 | bitmap_set_bit (local_processed, uregno); | |
312 | } | |
313 | } | |
314 | } | |
315 | ||
316 | /* Add the length of the block to all of the registers that were not | |
317 | referenced, but still live in this block. */ | |
318 | bitmap_and_compl_into (live, local_processed); | |
319 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) | |
320 | REG_LIVE_LENGTH (regno) += luid; | |
321 | ||
322 | bitmap_clear (local_processed); | |
323 | bitmap_clear (local_live); | |
324 | } | |
325 | ||
326 | ||
327 | /* Compute register info: lifetime, bb, and number of defs and uses. */ | |
328 | void | |
329 | regstat_compute_ri (void) | |
330 | { | |
331 | basic_block bb; | |
332 | bitmap live = BITMAP_ALLOC (&df_bitmap_obstack); | |
333 | bitmap do_not_gen = BITMAP_ALLOC (&df_bitmap_obstack); | |
334 | bitmap artificial_uses = BITMAP_ALLOC (&df_bitmap_obstack); | |
335 | bitmap local_live = BITMAP_ALLOC (&df_bitmap_obstack); | |
336 | bitmap local_processed = BITMAP_ALLOC (&df_bitmap_obstack); | |
337 | unsigned int regno; | |
338 | bitmap_iterator bi; | |
339 | ||
340 | /* Initialize everything. */ | |
341 | ||
342 | gcc_assert (!reg_info_p); | |
343 | ||
344 | timevar_push (TV_REG_STATS); | |
345 | setjmp_crosses = BITMAP_ALLOC (&df_bitmap_obstack); | |
346 | max_regno = max_reg_num (); | |
347 | reg_info_p_size = max_regno; | |
348 | reg_info_p = xcalloc (max_regno, sizeof (struct reg_info_t)); | |
349 | ||
350 | FOR_EACH_BB (bb) | |
351 | { | |
352 | regstat_bb_compute_ri (bb->index, live, do_not_gen, artificial_uses, | |
353 | local_live, local_processed); | |
354 | } | |
355 | ||
356 | BITMAP_FREE (live); | |
357 | BITMAP_FREE (do_not_gen); | |
358 | BITMAP_FREE (artificial_uses); | |
359 | ||
360 | /* See the setjmp comment in regstat_ri_bb_compute. */ | |
361 | EXECUTE_IF_SET_IN_BITMAP (setjmp_crosses, FIRST_PSEUDO_REGISTER, regno, bi) | |
362 | { | |
363 | REG_BASIC_BLOCK (regno) = REG_BLOCK_UNKNOWN; | |
364 | REG_LIVE_LENGTH (regno) = -1; | |
365 | } | |
366 | ||
367 | BITMAP_FREE (local_live); | |
368 | BITMAP_FREE (local_processed); | |
369 | timevar_pop (TV_REG_STATS); | |
370 | } | |
371 | ||
372 | ||
373 | /* Free all storage associated with the problem. */ | |
374 | ||
375 | void | |
376 | regstat_free_ri (void) | |
377 | { | |
378 | gcc_assert (reg_info_p); | |
379 | reg_info_p_size = 0; | |
380 | free (reg_info_p); | |
381 | reg_info_p = NULL; | |
382 | ||
383 | BITMAP_FREE (setjmp_crosses); | |
384 | } | |
385 | ||
386 | ||
387 | /* Return a bitmap containing the set of registers that cross a setjmp. | |
388 | The client should not change or delete this bitmap. */ | |
389 | ||
390 | bitmap | |
391 | regstat_get_setjmp_crosses (void) | |
392 | { | |
393 | return setjmp_crosses; | |
394 | } | |
395 | ||
396 | /*---------------------------------------------------------------------------- | |
397 | Process REG_N_CALLS_CROSSED. | |
398 | ||
399 | This is used by sched_deps. A good implementation of sched-deps | |
400 | would really process the blocks directly rather than going thur | |
401 | lists of insns. If it did this, it could use the exact regs that | |
402 | cross an individual call rather than using this info that merges | |
403 | the info for all calls. | |
404 | ||
405 | ----------------------------------------------------------------------------*/ | |
406 | ||
407 | ||
408 | ||
409 | /* Compute callse crossed for BB. Live is a scratch bitvector. */ | |
410 | ||
411 | static void | |
412 | regstat_bb_compute_calls_crossed (unsigned int bb_index, bitmap live) | |
413 | { | |
414 | basic_block bb = BASIC_BLOCK (bb_index); | |
415 | rtx insn; | |
416 | struct df_ref **def_rec; | |
417 | struct df_ref **use_rec; | |
418 | ||
419 | bitmap_copy (live, df_get_live_out (bb)); | |
420 | ||
421 | /* Process the artificial defs and uses at the bottom of the block | |
422 | to begin processing. */ | |
423 | for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++) | |
424 | { | |
425 | struct df_ref *def = *def_rec; | |
426 | if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0) | |
427 | bitmap_clear_bit (live, DF_REF_REGNO (def)); | |
428 | } | |
429 | ||
430 | for (use_rec = df_get_artificial_uses (bb_index); *use_rec; use_rec++) | |
431 | { | |
432 | struct df_ref *use = *use_rec; | |
433 | if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0) | |
434 | bitmap_set_bit (live, DF_REF_REGNO (use)); | |
435 | } | |
436 | ||
437 | FOR_BB_INSNS_REVERSE (bb, insn) | |
438 | { | |
439 | unsigned int uid = INSN_UID (insn); | |
440 | unsigned int regno; | |
441 | ||
442 | if (!INSN_P (insn)) | |
443 | continue; | |
444 | ||
445 | /* Process the defs. */ | |
446 | if (CALL_P (insn)) | |
447 | { | |
448 | bitmap_iterator bi; | |
449 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) | |
450 | REG_N_CALLS_CROSSED (regno)++; | |
451 | } | |
452 | ||
453 | /* All of the defs except the return value are some sort of | |
454 | clobber. This code is for the return. */ | |
455 | for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++) | |
456 | { | |
457 | struct df_ref *def = *def_rec; | |
458 | if ((!CALL_P (insn)) | |
459 | || (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))) | |
460 | { | |
461 | /* Kill this register if it is not a subreg store or conditional store. */ | |
462 | if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) | |
463 | bitmap_clear_bit (live, DF_REF_REGNO (def)); | |
464 | } | |
465 | } | |
466 | ||
467 | for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++) | |
468 | { | |
469 | struct df_ref *use = *use_rec; | |
470 | bitmap_set_bit (live, DF_REF_REGNO (use)); | |
471 | } | |
472 | } | |
473 | } | |
474 | ||
475 | ||
476 | /* Compute register info: lifetime, bb, and number of defs and uses. */ | |
477 | void | |
478 | regstat_compute_calls_crossed (void) | |
479 | { | |
480 | basic_block bb; | |
481 | bitmap live = BITMAP_ALLOC (&df_bitmap_obstack); | |
482 | ||
483 | /* Initialize everything. */ | |
484 | gcc_assert (!reg_info_p); | |
485 | ||
486 | timevar_push (TV_REG_STATS); | |
487 | max_regno = max_reg_num (); | |
488 | reg_info_p_size = max_regno; | |
489 | reg_info_p = xcalloc (max_regno, sizeof (struct reg_info_t)); | |
490 | ||
491 | FOR_EACH_BB (bb) | |
492 | { | |
493 | regstat_bb_compute_calls_crossed (bb->index, live); | |
494 | } | |
495 | ||
496 | BITMAP_FREE (live); | |
497 | timevar_pop (TV_REG_STATS); | |
498 | } | |
499 | ||
500 | ||
501 | /* Free all storage associated with the problem. */ | |
502 | ||
503 | void | |
504 | regstat_free_calls_crossed (void) | |
505 | { | |
506 | gcc_assert (reg_info_p); | |
507 | reg_info_p_size = 0; | |
508 | free (reg_info_p); | |
509 | reg_info_p = NULL; | |
510 | } | |
511 |