1 | /* Scanning of rtl for dataflow analysis. |
2 | Copyright (C) 2007-2023 Free Software Foundation, Inc. |
3 | Contributed by Kenneth Zadeck (zadeck@naturalbridge.com). |
4 | |
5 | This file is part of GCC. |
6 | |
7 | GCC is free software; you can redistribute it and/or modify it under |
8 | the terms of the GNU General Public License as published by the Free |
9 | Software Foundation; either version 3, or (at your option) any later |
10 | version. |
11 | |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
15 | for more details. |
16 | |
17 | You should have received a copy of the GNU General Public License |
18 | along with GCC; see the file COPYING3. If not see |
19 | <http://www.gnu.org/licenses/>. */ |
20 | |
21 | |
22 | #include "config.h" |
23 | #include "system.h" |
24 | #include "coretypes.h" |
25 | #include "backend.h" |
26 | #include "rtl.h" |
27 | #include "predict.h" |
28 | #include "df.h" |
29 | #include "regs.h" |
30 | |
31 | |
32 | struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs; |
33 | |
34 | /*---------------------------------------------------------------------------- |
35 | REG_N_SETS and REG_N_REFS. |
36 | ----------------------------------------------------------------------------*/ |
37 | |
38 | /* If a pass need to change these values in some magical way or the |
39 | pass needs to have accurate values for these and is not using |
40 | incremental df scanning, then it should use REG_N_SETS and |
41 | REG_N_USES. If the pass is doing incremental scanning then it |
42 | should be getting the info from DF_REG_DEF_COUNT and |
43 | DF_REG_USE_COUNT. */ |
44 | |
45 | void |
46 | regstat_init_n_sets_and_refs (void) |
47 | { |
48 | unsigned int i; |
49 | unsigned int max_regno = max_reg_num (); |
50 | |
51 | timevar_push (tv: TV_REG_STATS); |
52 | df_grow_reg_info (); |
53 | gcc_assert (!regstat_n_sets_and_refs); |
54 | |
55 | regstat_n_sets_and_refs = XNEWVEC (struct regstat_n_sets_and_refs_t, max_regno); |
56 | |
57 | if (MAY_HAVE_DEBUG_BIND_INSNS) |
58 | for (i = 0; i < max_regno; i++) |
59 | { |
60 | int use_count; |
61 | df_ref use; |
62 | |
63 | use_count = DF_REG_USE_COUNT (i); |
64 | for (use = DF_REG_USE_CHAIN (i); use; use = DF_REF_NEXT_REG (use)) |
65 | if (DF_REF_INSN_INFO (use) && DEBUG_INSN_P (DF_REF_INSN (use))) |
66 | use_count--; |
67 | |
68 | |
69 | SET_REG_N_SETS (i, DF_REG_DEF_COUNT (i)); |
70 | SET_REG_N_REFS (i, use_count + REG_N_SETS (i)); |
71 | } |
72 | else |
73 | for (i = 0; i < max_regno; i++) |
74 | { |
75 | SET_REG_N_SETS (i, DF_REG_DEF_COUNT (i)); |
76 | SET_REG_N_REFS (i, DF_REG_USE_COUNT (i) + REG_N_SETS (i)); |
77 | } |
78 | timevar_pop (tv: TV_REG_STATS); |
79 | |
80 | } |
81 | |
82 | |
83 | /* Free the array that holds the REG_N_SETS and REG_N_REFS. */ |
84 | |
85 | void |
86 | regstat_free_n_sets_and_refs (void) |
87 | { |
88 | gcc_assert (regstat_n_sets_and_refs); |
89 | free (ptr: regstat_n_sets_and_refs); |
90 | regstat_n_sets_and_refs = NULL; |
91 | } |
92 | |
93 | |
94 | /*---------------------------------------------------------------------------- |
95 | REGISTER INFORMATION |
96 | |
97 | Process REG_N_DEATHS, REG_N_CALLS_CROSSED, and REG_BASIC_BLOCK. |
98 | |
99 | ----------------------------------------------------------------------------*/ |
100 | |
101 | static bitmap setjmp_crosses; |
102 | struct reg_info_t *reg_info_p; |
103 | |
104 | /* The number allocated elements of reg_info_p. */ |
105 | size_t reg_info_p_size; |
106 | |
107 | /* Compute register info: lifetime, bb, and number of defs and uses |
108 | for basic block BB. LIVE is a scratch bitvector used here. */ |
109 | |
110 | static void |
111 | regstat_bb_compute_ri (basic_block bb, bitmap live) |
112 | { |
113 | rtx_insn *insn; |
114 | df_ref def, use; |
115 | bitmap_iterator bi; |
116 | unsigned int regno; |
117 | |
118 | bitmap_copy (live, df_get_live_out (bb)); |
119 | |
120 | /* Process the regs live at the end of the block. Mark them as |
121 | not local to any one basic block. */ |
122 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) |
123 | REG_BASIC_BLOCK (regno) = REG_BLOCK_GLOBAL; |
124 | |
125 | /* Process the artificial defs and uses at the bottom of the block |
126 | to begin processing. */ |
127 | FOR_EACH_ARTIFICIAL_DEF (def, bb->index) |
128 | if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0) |
129 | bitmap_clear_bit (live, DF_REF_REGNO (def)); |
130 | |
131 | FOR_EACH_ARTIFICIAL_USE (use, bb->index) |
132 | if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0) |
133 | { |
134 | regno = DF_REF_REGNO (use); |
135 | bitmap_set_bit (live, regno); |
136 | } |
137 | |
138 | FOR_BB_INSNS_REVERSE (bb, insn) |
139 | { |
140 | struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn); |
141 | bitmap_iterator bi; |
142 | rtx link; |
143 | |
144 | if (!NONDEBUG_INSN_P (insn)) |
145 | continue; |
146 | |
147 | link = REG_NOTES (insn); |
148 | while (link) |
149 | { |
150 | if (REG_NOTE_KIND (link) == REG_DEAD) |
151 | REG_N_DEATHS (REGNO (XEXP (link, 0)))++; |
152 | link = XEXP (link, 1); |
153 | } |
154 | |
155 | /* Process the defs. */ |
156 | if (CALL_P (insn)) |
157 | { |
158 | bool set_jump = (find_reg_note (insn, REG_SETJMP, NULL) != NULL); |
159 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) |
160 | { |
161 | REG_N_CALLS_CROSSED (regno)++; |
162 | |
163 | /* We have a problem with any pseudoreg that lives |
164 | across the setjmp. ANSI says that if a user variable |
165 | does not change in value between the setjmp and the |
166 | longjmp, then the longjmp preserves it. This |
167 | includes longjmp from a place where the pseudo |
168 | appears dead. (In principle, the value still exists |
169 | if it is in scope.) If the pseudo goes in a hard |
170 | reg, some other value may occupy that hard reg where |
171 | this pseudo is dead, thus clobbering the pseudo. |
172 | Conclusion: such a pseudo must not go in a hard |
173 | reg. */ |
174 | if (set_jump) |
175 | bitmap_set_bit (setjmp_crosses, regno); |
176 | } |
177 | } |
178 | |
179 | /* All of the defs except the return value are some sort of |
180 | clobber. This code is for the return. */ |
181 | FOR_EACH_INSN_INFO_DEF (def, insn_info) |
182 | { |
183 | if ((!CALL_P (insn)) |
184 | || (!(DF_REF_FLAGS (def) |
185 | & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))) |
186 | { |
187 | unsigned int dregno = DF_REF_REGNO (def); |
188 | |
189 | /* Kill this register if it is not a subreg store or |
190 | conditional store. |
191 | ??? This means that any partial store is live from |
192 | the last use in a basic block to the start of this |
193 | basic block. */ |
194 | if (!(DF_REF_FLAGS (def) |
195 | & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) |
196 | bitmap_clear_bit (live, dregno); |
197 | |
198 | if (dregno >= FIRST_PSEUDO_REGISTER) |
199 | { |
200 | REG_FREQ (dregno) += REG_FREQ_FROM_BB (bb); |
201 | REG_FREQ (dregno) = |
202 | MIN (REG_FREQ (dregno), REG_FREQ_MAX); |
203 | |
204 | if (REG_BASIC_BLOCK (dregno) == REG_BLOCK_UNKNOWN) |
205 | REG_BASIC_BLOCK (dregno) = bb->index; |
206 | else if (REG_BASIC_BLOCK (dregno) != bb->index) |
207 | REG_BASIC_BLOCK (dregno) = REG_BLOCK_GLOBAL; |
208 | } |
209 | } |
210 | } |
211 | |
212 | FOR_EACH_INSN_INFO_USE (use, insn_info) |
213 | { |
214 | unsigned int uregno = DF_REF_REGNO (use); |
215 | |
216 | if (uregno >= FIRST_PSEUDO_REGISTER) |
217 | { |
218 | REG_FREQ (uregno) += REG_FREQ_FROM_BB (bb); |
219 | REG_FREQ (uregno) = |
220 | MIN (REG_FREQ (uregno), REG_FREQ_MAX); |
221 | |
222 | if (REG_BASIC_BLOCK (uregno) == REG_BLOCK_UNKNOWN) |
223 | REG_BASIC_BLOCK (uregno) = bb->index; |
224 | else if (REG_BASIC_BLOCK (uregno) != bb->index) |
225 | REG_BASIC_BLOCK (uregno) = REG_BLOCK_GLOBAL; |
226 | } |
227 | } |
228 | } |
229 | } |
230 | |
231 | |
232 | /* Compute register info: lifetime, bb, and number of defs and uses. */ |
233 | void |
234 | regstat_compute_ri (void) |
235 | { |
236 | basic_block bb; |
237 | bitmap live = BITMAP_ALLOC (obstack: &df_bitmap_obstack); |
238 | unsigned int regno; |
239 | bitmap_iterator bi; |
240 | |
241 | /* Initialize everything. */ |
242 | |
243 | gcc_assert (!reg_info_p); |
244 | |
245 | timevar_push (tv: TV_REG_STATS); |
246 | setjmp_crosses = BITMAP_ALLOC (obstack: &df_bitmap_obstack); |
247 | max_regno = max_reg_num (); |
248 | reg_info_p_size = max_regno; |
249 | reg_info_p = XCNEWVEC (struct reg_info_t, max_regno); |
250 | |
251 | FOR_EACH_BB_FN (bb, cfun) |
252 | { |
253 | regstat_bb_compute_ri (bb, live); |
254 | } |
255 | |
256 | BITMAP_FREE (live); |
257 | |
258 | /* See the setjmp comment in regstat_bb_compute_ri. */ |
259 | EXECUTE_IF_SET_IN_BITMAP (setjmp_crosses, FIRST_PSEUDO_REGISTER, regno, bi) |
260 | { |
261 | REG_BASIC_BLOCK (regno) = REG_BLOCK_UNKNOWN; |
262 | } |
263 | |
264 | timevar_pop (tv: TV_REG_STATS); |
265 | } |
266 | |
267 | |
268 | /* Free all storage associated with the problem. */ |
269 | |
270 | void |
271 | regstat_free_ri (void) |
272 | { |
273 | gcc_assert (reg_info_p); |
274 | reg_info_p_size = 0; |
275 | free (ptr: reg_info_p); |
276 | reg_info_p = NULL; |
277 | |
278 | BITMAP_FREE (setjmp_crosses); |
279 | } |
280 | |
281 | |
282 | /* Return a bitmap containing the set of registers that cross a setjmp. |
283 | The client should not change or delete this bitmap. */ |
284 | |
285 | bitmap |
286 | regstat_get_setjmp_crosses (void) |
287 | { |
288 | return setjmp_crosses; |
289 | } |
290 | |
291 | /*---------------------------------------------------------------------------- |
292 | Process REG_N_CALLS_CROSSED. |
293 | |
294 | This is used by sched_deps. A good implementation of sched-deps |
295 | would really process the blocks directly rather than going through |
296 | lists of insns. If it did this, it could use the exact regs that |
297 | cross an individual call rather than using this info that merges |
298 | the info for all calls. |
299 | |
300 | ----------------------------------------------------------------------------*/ |
301 | |
302 | |
303 | |
304 | /* Compute calls crossed for BB. Live is a scratch bitvector. */ |
305 | |
306 | static void |
307 | regstat_bb_compute_calls_crossed (unsigned int bb_index, bitmap live) |
308 | { |
309 | basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index); |
310 | rtx_insn *insn; |
311 | df_ref def, use; |
312 | |
313 | bitmap_copy (live, df_get_live_out (bb)); |
314 | |
315 | /* Process the artificial defs and uses at the bottom of the block |
316 | to begin processing. */ |
317 | FOR_EACH_ARTIFICIAL_DEF (def, bb_index) |
318 | if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) == 0) |
319 | bitmap_clear_bit (live, DF_REF_REGNO (def)); |
320 | |
321 | FOR_EACH_ARTIFICIAL_USE (use, bb_index) |
322 | if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == 0) |
323 | bitmap_set_bit (live, DF_REF_REGNO (use)); |
324 | |
325 | FOR_BB_INSNS_REVERSE (bb, insn) |
326 | { |
327 | if (!NONDEBUG_INSN_P (insn)) |
328 | continue; |
329 | |
330 | gcc_assert (INSN_UID (insn) < (int) DF_INSN_SIZE ()); |
331 | struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn); |
332 | unsigned int regno; |
333 | |
334 | /* Process the defs. */ |
335 | if (CALL_P (insn)) |
336 | { |
337 | bitmap_iterator bi; |
338 | EXECUTE_IF_SET_IN_BITMAP (live, 0, regno, bi) |
339 | { |
340 | REG_N_CALLS_CROSSED (regno)++; |
341 | } |
342 | } |
343 | |
344 | /* All of the defs except the return value are some sort of |
345 | clobber. This code is for the return. */ |
346 | FOR_EACH_INSN_INFO_DEF (def, insn_info) |
347 | { |
348 | if ((!CALL_P (insn)) |
349 | || (!(DF_REF_FLAGS (def) & (DF_REF_MUST_CLOBBER | DF_REF_MAY_CLOBBER)))) |
350 | { |
351 | /* Kill this register if it is not a subreg store or conditional store. */ |
352 | if (!(DF_REF_FLAGS (def) & (DF_REF_PARTIAL | DF_REF_CONDITIONAL))) |
353 | bitmap_clear_bit (live, DF_REF_REGNO (def)); |
354 | } |
355 | } |
356 | |
357 | FOR_EACH_INSN_INFO_USE (use, insn_info) |
358 | bitmap_set_bit (live, DF_REF_REGNO (use)); |
359 | } |
360 | } |
361 | |
362 | |
363 | /* Compute register info: lifetime, bb, and number of defs and uses. */ |
364 | void |
365 | regstat_compute_calls_crossed (void) |
366 | { |
367 | basic_block bb; |
368 | bitmap live = BITMAP_ALLOC (obstack: &df_bitmap_obstack); |
369 | |
370 | /* Initialize everything. */ |
371 | gcc_assert (!reg_info_p); |
372 | |
373 | timevar_push (tv: TV_REG_STATS); |
374 | max_regno = max_reg_num (); |
375 | reg_info_p_size = max_regno; |
376 | reg_info_p = XCNEWVEC (struct reg_info_t, max_regno); |
377 | |
378 | FOR_EACH_BB_FN (bb, cfun) |
379 | { |
380 | regstat_bb_compute_calls_crossed (bb_index: bb->index, live); |
381 | } |
382 | |
383 | BITMAP_FREE (live); |
384 | timevar_pop (tv: TV_REG_STATS); |
385 | } |
386 | |
387 | |
388 | /* Free all storage associated with the problem. */ |
389 | |
390 | void |
391 | regstat_free_calls_crossed (void) |
392 | { |
393 | gcc_assert (reg_info_p); |
394 | reg_info_p_size = 0; |
395 | free (ptr: reg_info_p); |
396 | reg_info_p = NULL; |
397 | } |
398 | |
399 | /* Dump the register info to FILE. */ |
400 | |
401 | void |
402 | dump_reg_info (FILE *file) |
403 | { |
404 | unsigned int i, max = max_reg_num (); |
405 | if (reload_completed) |
406 | return; |
407 | |
408 | if (reg_info_p_size < max) |
409 | max = reg_info_p_size; |
410 | |
411 | fprintf (stream: file, format: "%d registers.\n" , max); |
412 | for (i = FIRST_PSEUDO_REGISTER; i < max; i++) |
413 | { |
414 | enum reg_class rclass, altclass; |
415 | |
416 | if (regstat_n_sets_and_refs) |
417 | fprintf (stream: file, format: "\nRegister %d used %d times" , |
418 | i, REG_N_REFS (regno: i)); |
419 | else if (df) |
420 | fprintf (stream: file, format: "\nRegister %d used %d times" , |
421 | i, DF_REG_USE_COUNT (i) + DF_REG_DEF_COUNT (i)); |
422 | |
423 | if (REG_BASIC_BLOCK (i) >= NUM_FIXED_BLOCKS) |
424 | fprintf (stream: file, format: " in block %d" , REG_BASIC_BLOCK (i)); |
425 | if (regstat_n_sets_and_refs) |
426 | fprintf (stream: file, format: "; set %d time%s" , REG_N_SETS (regno: i), |
427 | (REG_N_SETS (regno: i) == 1) ? "" : "s" ); |
428 | else if (df) |
429 | fprintf (stream: file, format: "; set %d time%s" , DF_REG_DEF_COUNT (i), |
430 | (DF_REG_DEF_COUNT (i) == 1) ? "" : "s" ); |
431 | if (regno_reg_rtx[i] != NULL && REG_USERVAR_P (regno_reg_rtx[i])) |
432 | fputs (s: "; user var" , stream: file); |
433 | if (REG_N_DEATHS (i) != 1) |
434 | fprintf (stream: file, format: "; dies in %d places" , REG_N_DEATHS (i)); |
435 | if (REG_N_CALLS_CROSSED (i) == 1) |
436 | fputs (s: "; crosses 1 call" , stream: file); |
437 | else if (REG_N_CALLS_CROSSED (i)) |
438 | fprintf (stream: file, format: "; crosses %d calls" , REG_N_CALLS_CROSSED (i)); |
439 | if (regno_reg_rtx[i] != NULL |
440 | && maybe_ne (PSEUDO_REGNO_BYTES (i), UNITS_PER_WORD)) |
441 | { |
442 | fprintf (stream: file, format: "; " ); |
443 | print_dec (PSEUDO_REGNO_BYTES (i), file, sgn: SIGNED); |
444 | fprintf (stream: file, format: " bytes" ); |
445 | } |
446 | |
447 | rclass = reg_preferred_class (i); |
448 | altclass = reg_alternate_class (i); |
449 | if (rclass != GENERAL_REGS || altclass != ALL_REGS) |
450 | { |
451 | if (altclass == ALL_REGS || rclass == ALL_REGS) |
452 | fprintf (stream: file, format: "; pref %s" , reg_class_names[(int) rclass]); |
453 | else if (altclass == NO_REGS) |
454 | fprintf (stream: file, format: "; %s or none" , reg_class_names[(int) rclass]); |
455 | else |
456 | fprintf (stream: file, format: "; pref %s, else %s" , |
457 | reg_class_names[(int) rclass], |
458 | reg_class_names[(int) altclass]); |
459 | } |
460 | |
461 | if (regno_reg_rtx[i] != NULL && REG_POINTER (regno_reg_rtx[i])) |
462 | fputs (s: "; pointer" , stream: file); |
463 | fputs (s: ".\n" , stream: file); |
464 | } |
465 | } |
466 | |
467 | |