?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
2009-01-07 Zoltan Varga <vargaz@gmail.com>
[mono-project.git] / mono / mini / ssa2.c
blob2bccc82b06f52139176ef22fb2fbb9744c2ffcc2
1 /*
2 * ssa.c: Static single assign form support for the JIT compiler.
3 *
4 * Author:
5 * Dietmar Maurer (dietmar@ximian.com)
6 *
7 * (C) 2003 Ximian, Inc.
8 */
9 #include <string.h>
10 #include <mono/metadata/debug-helpers.h>
11 #include <mono/metadata/mempool.h>
12 #include <mono/metadata/mempool-internals.h>
13
14 #ifndef DISABLE_JIT
15
16 #define NEW_IR
17 #include "mini.h"
18
19 #define USE_ORIGINAL_VARS
20 #define CREATE_PRUNED_SSA
21
22 //#define DEBUG_SSA 1
23
24 #define NEW_PHI(cfg,dest,val) do { \
25 (dest) = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoInst)); \
26 (dest)->opcode = OP_PHI; \
27 (dest)->inst_c0 = (val); \
28 (dest)->dreg = (dest)->sreg1 = (dest)->sreg2 = -1; \
29 } while (0)
30
31 #define NEW_ICONST(cfg,dest,val) do { \
32 (dest) = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoInst)); \
33 (dest)->opcode = OP_ICONST; \
34 (dest)->inst_c0 = (val); \
35 (dest)->type = STACK_I4; \
36 (dest)->dreg = (dest)->sreg1 = (dest)->sreg2 = -1; \
37 } while (0)
38
39 typedef struct {
40 MonoBasicBlock *bb;
41 MonoInst *inst;
42 } MonoVarUsageInfo;
43
44 static void
45 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
46 {
47 int i;
48
49 for (i = 0; i < bb->out_count; i++) {
50 if (bb->out_bb [i] == target) {
51 bb->out_bb [i] = bb->out_bb [--bb->out_count];
52 break;
53 }
54 }
55 for (i = 0; i < target->in_count; i++) {
56 if (target->in_bb [i] == bb) {
57 target->in_bb [i] = target->in_bb [--target->in_count];
58 break;
59
60 }
61 }
62 }
63
64 static void
65 unlink_unused_bblocks (MonoCompile *cfg)
66 {
67 int i, j;
68 MonoBasicBlock *bb;
69
70 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
71
72 if (G_UNLIKELY (cfg->verbose_level > 1))
73 printf ("\nUNLINK UNUSED BBLOCKS:\n");
74
75 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
76 if (!(bb->next_bb->flags & BB_REACHABLE)) {
77 bb->next_bb = bb->next_bb->next_bb;
78 } else
79 bb = bb->next_bb;
80 }
81
82 for (i = 1; i < cfg->num_bblocks; i++) {
83 bb = cfg->bblocks [i];
84
85 if (!(bb->flags & BB_REACHABLE)) {
86 for (j = 0; j < bb->in_count; j++) {
87 unlink_target (bb->in_bb [j], bb);
88 }
89 for (j = 0; j < bb->out_count; j++) {
90 unlink_target (bb, bb->out_bb [j]);
91 }
92 if (G_UNLIKELY (cfg->verbose_level > 1))
93 printf ("\tUnlinked BB%d\n", bb->block_num);
94 }
95
96 }
97 }
98
99 /**
100 * remove_bb_from_phis:
101 *
102 * Remove BB from the PHI statements in TARGET.
103 */
104 static void
105 remove_bb_from_phis (MonoCompile *cfg, MonoBasicBlock *bb, MonoBasicBlock *target)
106 {
107 MonoInst *ins;
108 int i, j;
109
110 for (i = 0; i < target->in_count; i++) {
111 if (target->in_bb [i] == bb) {
112 break;
113 }
114 }
115 g_assert (i < target->in_count);
116
117 for (ins = target->code; ins; ins = ins->next) {
118 if (MONO_IS_PHI (ins)) {
119 for (j = i; j < ins->inst_phi_args [0] - 1; ++j)
120 ins->inst_phi_args [j + 1] = ins->inst_phi_args [j + 2];
121 ins->inst_phi_args [0] --;
122 }
123 else
124 break;
125 }
126 }
127
128 static inline int
129 op_phi_to_move (int opcode)
130 {
131 switch (opcode) {
132 case OP_PHI:
133 return OP_MOVE;
134 case OP_FPHI:
135 return OP_FMOVE;
136 case OP_VPHI:
137 return OP_VMOVE;
138 case OP_XPHI:
139 return OP_XMOVE;
140 default:
141 g_assert_not_reached ();
142 }
143
144 return -1;
145 }
146
147 static inline void
148 record_use (MonoCompile *cfg, MonoInst *var, MonoBasicBlock *bb, MonoInst *ins)
149 {
150 MonoMethodVar *info;
151 MonoVarUsageInfo *ui = mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
152
153 info = MONO_VARINFO (cfg, var->inst_c0);
154
155 ui->bb = bb;
156 ui->inst = ins;
157 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
158 }
159
160 typedef struct {
161 MonoInst *var;
162 int idx;
163 } RenameInfo;
164
165 /**
166 * mono_ssa_rename_vars2:
167 *
168 * Implement renaming of SSA variables. Also compute def-use information in parallel.
169 * @stack_history points to an area of memory which can be used for storing changes
170 * made to the stack, so they can be reverted later.
171 */
172 static void
173 mono_ssa_rename_vars2 (MonoCompile *cfg, int max_vars, MonoBasicBlock *bb, gboolean *originals_used, MonoInst **stack, guint32 *lvreg_stack, gboolean *lvreg_defined, RenameInfo *stack_history, int stack_history_size)
174 {
175 MonoInst *ins, *new_var;
176 int i, j, idx;
177 GSList *tmp;
178 int stack_history_len = 0;
179
180 if (cfg->verbose_level >= 4)
181 printf ("\nRENAME VARS BLOCK %d:\n", bb->block_num);
182
183 /* First pass: Create new vars */
184 for (ins = bb->code; ins; ins = ins->next) {
185 const char *spec = INS_INFO (ins->opcode);
186
187 #ifdef DEBUG_SSA
188 printf ("\tProcessing "); mono_print_ins (ins);
189 #endif
190 if (ins->opcode == OP_NOP)
191 continue;
192
193 /* SREG1 */
194 if (spec [MONO_INST_SRC1] != ' ') {
195 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg1);
196 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
197 int idx = var->inst_c0;
198 if (stack [idx]) {
199 if (var->opcode != OP_ARG)
200 g_assert (stack [idx]);
201 ins->sreg1 = stack [idx]->dreg;
202 record_use (cfg, stack [idx], bb, ins);
203 }
204 else
205 record_use (cfg, var, bb, ins);
206 }
207 else if (G_UNLIKELY (!var && lvreg_stack [ins->sreg1]))
208 ins->sreg1 = lvreg_stack [ins->sreg1];
209 }
210
211 /* SREG2 */
212 if (spec [MONO_INST_SRC2] != ' ') {
213 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg2);
214 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
215 int idx = var->inst_c0;
216 if (stack [idx]) {
217 if (var->opcode != OP_ARG)
218 g_assert (stack [idx]);
219
220 ins->sreg2 = stack [idx]->dreg;
221 record_use (cfg, stack [idx], bb, ins);
222 }
223 else
224 record_use (cfg, var, bb, ins);
225 }
226 else if (G_UNLIKELY (!var && lvreg_stack [ins->sreg2]))
227 ins->sreg2 = lvreg_stack [ins->sreg2];
228 }
229
230 if (MONO_IS_STORE_MEMBASE (ins)) {
231 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
232 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
233 int idx = var->inst_c0;
234 if (stack [idx]) {
235 if (var->opcode != OP_ARG)
236 g_assert (stack [idx]);
237 ins->dreg = stack [idx]->dreg;
238 record_use (cfg, stack [idx], bb, ins);
239 }
240 else
241 record_use (cfg, var, bb, ins);
242 }
243 else if (G_UNLIKELY (!var && lvreg_stack [ins->dreg]))
244 ins->dreg = lvreg_stack [ins->dreg];
245 }
246
247 /* DREG */
248 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
249 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
250 MonoMethodVar *info;
251
252 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
253 idx = var->inst_c0;
254 g_assert (idx < max_vars);
255
256 if (var->opcode == OP_ARG)
257 originals_used [idx] = TRUE;
258
259 /* FIXME: */
260 g_assert (stack_history_len < stack_history_size);
261 stack_history [stack_history_len].var = stack [idx];
262 stack_history [stack_history_len].idx = idx;
263 stack_history_len ++;
264
265 if (originals_used [idx]) {
266 new_var = mono_compile_create_var (cfg, var->inst_vtype, OP_LOCAL);
267 new_var->flags = var->flags;
268 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
269
270 if (cfg->verbose_level >= 4)
271 printf (" R%d -> R%d\n", var->dreg, new_var->dreg);
272
273 stack [idx] = new_var;
274
275 ins->dreg = new_var->dreg;
276 var = new_var;
277 }
278 else {
279 stack [idx] = var;
280 originals_used [idx] = TRUE;
281 }
282
283 info = MONO_VARINFO (cfg, var->inst_c0);
284 info->def = ins;
285 info->def_bb = bb;
286 }
287 else if (G_UNLIKELY (!var && lvreg_defined [ins->dreg] && (ins->dreg >= MONO_MAX_IREGS))) {
288 /* Perform renaming for local vregs */
289 lvreg_stack [ins->dreg] = mono_alloc_preg (cfg);
290 ins->dreg = lvreg_stack [ins->dreg];
291 }
292 else
293 lvreg_defined [ins->dreg] = TRUE;
294 }
295
296 #ifdef DEBUG_SSA
297 printf ("\tAfter processing "); mono_print_ins (ins);
298 #endif
299
300 }
301
302 /* Rename PHI arguments in succeeding bblocks */
303 for (i = 0; i < bb->out_count; i++) {
304 MonoBasicBlock *n = bb->out_bb [i];
305
306 for (j = 0; j < n->in_count; j++)
307 if (n->in_bb [j] == bb)
308 break;
309
310 for (ins = n->code; ins; ins = ins->next) {
311 if (MONO_IS_PHI (ins)) {
312 idx = ins->inst_c0;
313 if (stack [idx])
314 new_var = stack [idx];
315 else
316 new_var = cfg->varinfo [idx];
317 #ifdef DEBUG_SSA
318 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
319 #endif
320 ins->inst_phi_args [j + 1] = new_var->dreg;
321 record_use (cfg, new_var, n, ins);
322 if (G_UNLIKELY (cfg->verbose_level >= 4))
323 printf ("\tAdd PHI R%d <- R%d to BB%d\n", ins->dreg, new_var->dreg, n->block_num);
324 }
325 else
326 /* The phi nodes are at the beginning of the bblock */
327 break;
328 }
329 }
330
331 if (bb->dominated) {
332 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
333 mono_ssa_rename_vars2 (cfg, max_vars, (MonoBasicBlock *)tmp->data, originals_used, stack, lvreg_stack, lvreg_defined, stack_history + stack_history_len, stack_history_size - stack_history_len);
334 }
335 }
336
337 /* Restore stack */
338 for (i = stack_history_len - 1; i >= 0; i--) {
339 stack [stack_history [i].idx] = stack_history [i].var;
340 }
341
342 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
343 }
344
345 void
346 mono_ssa_compute2 (MonoCompile *cfg)
347 {
348 int i, j, idx, bitsize;
349 MonoBitSet *set;
350 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
351 MonoInst *ins, **stack;
352 guint8 *buf, *buf_start;
353 RenameInfo *stack_history;
354 int stack_history_size;
355 gboolean *originals;
356 guint32 *lvreg_stack;
357 gboolean *lvreg_defined;
358
359 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
360
361 /* we dont support methods containing exception clauses */
362 g_assert (mono_method_get_header (cfg->method)->num_clauses == 0);
363 g_assert (!cfg->disable_ssa);
364
365 if (cfg->verbose_level >= 4)
366 printf ("\nCOMPUTE SSA %d (R%d-)\n\n", cfg->num_varinfo, cfg->next_vreg);
367
368 #ifdef CREATE_PRUNED_SSA
369 /* we need liveness for pruned SSA */
370 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
371 mono_analyze_liveness (cfg);
372 #endif
373
374 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
375
376 bitsize = mono_bitset_alloc_size (cfg->num_bblocks, 0);
377 buf = buf_start = g_malloc0 (mono_bitset_alloc_size (cfg->num_bblocks, 0) * cfg->num_varinfo);
378
379 for (i = 0; i < cfg->num_varinfo; ++i) {
380 vinfo [i].def_in = mono_bitset_mem_new (buf, cfg->num_bblocks, 0);
381 buf += bitsize;
382 vinfo [i].idx = i;
383 /* implicit reference at start */
384 mono_bitset_set_fast (vinfo [i].def_in, 0);
385 }
386
387 for (i = 0; i < cfg->num_bblocks; ++i) {
388 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], ins) {
389 if (ins->opcode == OP_NOP)
390 continue;
391
392 if (!MONO_IS_STORE_MEMBASE (ins) && get_vreg_to_inst (cfg, ins->dreg)) {
393 mono_bitset_set_fast (vinfo [get_vreg_to_inst (cfg, ins->dreg)->inst_c0].def_in, i);
394 }
395 }
396 }
397
398 /* insert phi functions */
399 for (i = 0; i < cfg->num_varinfo; ++i) {
400 MonoInst *var = cfg->varinfo [i];
401
402 #if SIZEOF_VOID_P == 4
403 if (var->type == STACK_I8)
404 continue;
405 #endif
406 if (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))
407 continue;
408
409 /* Most variables have only one definition */
410 if (mono_bitset_count (vinfo [i].def_in) <= 1)
411 continue;
412
413 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
414
415 if (cfg->verbose_level >= 4) {
416 if (mono_bitset_count (set) > 0) {
417 printf ("\tR%d needs PHI functions in ", var->dreg);
418 mono_blockset_print (cfg, set, "", -1);
419 }
420 }
421
422 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
423 MonoBasicBlock *bb = cfg->bblocks [idx];
424
425 /* fixme: create pruned SSA? we would need liveness information for that */
426
427 if (bb == cfg->bb_exit)
428 continue;
429
430 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
431 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
432 continue;
433 }
434
435 NEW_PHI (cfg, ins, i);
436
437 switch (var->type) {
438 case STACK_I4:
439 case STACK_I8:
440 case STACK_PTR:
441 case STACK_MP:
442 case STACK_OBJ:
443 ins->opcode = OP_PHI;
444 break;
445 case STACK_R8:
446 ins->opcode = OP_FPHI;
447 break;
448 case STACK_VTYPE:
449 ins->opcode = MONO_CLASS_IS_SIMD (cfg, var->klass) ? OP_XPHI : OP_VPHI;
450 ins->klass = var->klass;
451 break;
452 }
453
454 ins->inst_phi_args = mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
455 ins->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
456
457 /* For debugging */
458 for (j = 0; j < cfg->bblocks [idx]->in_count; ++j)
459 ins->inst_phi_args [j + 1] = -1;
460
461 ins->dreg = cfg->varinfo [i]->dreg;
462
463 mono_bblock_insert_before_ins (bb, bb->code, ins);
464
465 #ifdef DEBUG_SSA
466 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
467 #endif
468 }
469 }
470
471 /* free the stuff */
472 g_free (vinfo);
473 g_free (buf_start);
474
475 /* Renaming phase */
476
477 stack = alloca (sizeof (MonoInst *) * cfg->num_varinfo);
478 memset (stack, 0, sizeof (MonoInst *) * cfg->num_varinfo);
479
480 lvreg_stack = g_new0 (guint32, cfg->next_vreg);
481 lvreg_defined = g_new0 (gboolean, cfg->next_vreg);
482 stack_history_size = 10240;
483 stack_history = g_new (RenameInfo, stack_history_size);
484 originals = g_new0 (gboolean, cfg->num_varinfo);
485 mono_ssa_rename_vars2 (cfg, cfg->num_varinfo, cfg->bb_entry, originals, stack, lvreg_stack, lvreg_defined, stack_history, stack_history_size);
486 g_free (stack_history);
487 g_free (originals);
488
489 if (cfg->verbose_level >= 4)
490 printf ("\nEND COMPUTE SSA.\n\n");
491
492 cfg->comp_done |= MONO_COMP_SSA;
493 }
494
495 void
496 mono_ssa_remove2 (MonoCompile *cfg)
497 {
498 MonoInst *ins, *var, *move;
499 int i, j, first;
500
501 g_assert (cfg->comp_done & MONO_COMP_SSA);
502
503 for (i = 0; i < cfg->num_bblocks; ++i) {
504 MonoBasicBlock *bb = cfg->bblocks [i];
505
506 if (cfg->verbose_level >= 4)
507 printf ("\nREMOVE SSA %d:\n", bb->block_num);
508
509 for (ins = bb->code; ins; ins = ins->next) {
510 if (MONO_IS_PHI (ins)) {
511 g_assert (ins->inst_phi_args [0] == bb->in_count);
512 var = get_vreg_to_inst (cfg, ins->dreg);
513
514 /* Check for PHI nodes where all the inputs are the same */
515 first = ins->inst_phi_args [1];
516
517 for (j = 1; j < bb->in_count; ++j)
518 if (first != ins->inst_phi_args [j + 1])
519 break;
520
521 if ((bb->in_count > 1) && (j == bb->in_count)) {
522 ins->opcode = op_phi_to_move (ins->opcode);
523 if (ins->opcode == OP_VMOVE)
524 g_assert (ins->klass);
525 ins->sreg1 = first;
526 } else {
527 for (j = 0; j < bb->in_count; j++) {
528 MonoBasicBlock *pred = bb->in_bb [j];
529 int sreg = ins->inst_phi_args [j + 1];
530
531 if (cfg->verbose_level >= 4)
532 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
533 if (var->dreg != sreg) {
534 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
535 if (move->opcode == OP_VMOVE) {
536 g_assert (ins->klass);
537 move->klass = ins->klass;
538 }
539 move->dreg = var->dreg;
540 move->sreg1 = sreg;
541 mono_add_ins_to_end (pred, move);
542 }
543 }
544
545 ins->opcode = OP_NOP;
546 ins->dreg = -1;
547 }
548 }
549 }
550 }
551
552 if (cfg->verbose_level >= 4) {
553 for (i = 0; i < cfg->num_bblocks; ++i) {
554 MonoBasicBlock *bb = cfg->bblocks [i];
555
556 mono_print_bb (bb, "AFTER REMOVE SSA:");
557 }
558 }
559
560 /*
561 * Removal of SSA form introduces many copies. To avoid this, we tyry to coalesce
562 * the variables if possible. Since the newly introduced SSA variables don't
563 * have overlapping live ranges (because we don't do agressive optimization), we
564 * can coalesce them into the original variable.
565 */
566
567 for (i = 0; i < cfg->num_bblocks; ++i) {
568 MonoBasicBlock *bb = cfg->bblocks [i];
569
570 for (ins = bb->code; ins; ins = ins->next) {
571 const char *spec = INS_INFO (ins->opcode);
572
573 if (ins->opcode == OP_NOP)
574 continue;
575
576 if (spec [MONO_INST_DEST] != ' ') {
577 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
578
579 if (var) {
580 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
581
582 /*
583 * The third condition avoids coalescing with variables eliminated
584 * during deadce.
585 */
586 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
587 printf ("COALESCE: R%d -> R%d\n", ins->dreg, cfg->varinfo [vmv->reg]->dreg);
588 ins->dreg = cfg->varinfo [vmv->reg]->dreg;
589 }
590 }
591 }
592
593 if (spec [MONO_INST_SRC1] != ' ') {
594 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg1);
595
596 if (var) {
597 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
598
599 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
600 printf ("COALESCE: R%d -> R%d\n", ins->sreg1, cfg->varinfo [vmv->reg]->dreg);
601 ins->sreg1 = cfg->varinfo [vmv->reg]->dreg;
602 }
603 }
604 }
605
606 if (spec [MONO_INST_SRC2] != ' ') {
607 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg2);
608
609 if (var) {
610 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
611
612 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
613 printf ("COALESCE: R%d -> R%d\n", ins->sreg2, cfg->varinfo [vmv->reg]->dreg);
614 ins->sreg2 = cfg->varinfo [vmv->reg]->dreg;
615 }
616 }
617 }
618
619 }
620 }
621
622 for (i = 0; i < cfg->num_varinfo; ++i) {
623 MONO_VARINFO (cfg, i)->reg = -1;
624 }
625
626 if (cfg->comp_done & MONO_COMP_REACHABILITY)
627 unlink_unused_bblocks (cfg);
628
629 cfg->comp_done &= ~MONO_COMP_LIVENESS;
630
631 cfg->comp_done &= ~MONO_COMP_SSA;
632 }
633
634 static void
635 mono_ssa_create_def_use (MonoCompile *cfg)
636 {
637 MonoBasicBlock *bb;
638 MonoInst *ins;
639 int i;
640
641 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
642
643 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
644 for (ins = bb->code; ins; ins = ins->next) {
645 const char *spec = INS_INFO (ins->opcode);
646 MonoMethodVar *info;
647
648 if (ins->opcode == OP_NOP)
649 continue;
650
651 /* SREG1 */
652 if (spec [MONO_INST_SRC1] != ' ') {
653 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg1);
654 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
655 record_use (cfg, var, bb, ins);
656 }
657
658 /* SREG2 */
659 if (spec [MONO_INST_SRC2] != ' ') {
660 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg2);
661 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
662 record_use (cfg, var, bb, ins);
663 }
664
665 if (MONO_IS_STORE_MEMBASE (ins)) {
666 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
667 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
668 record_use (cfg, var, bb, ins);
669 }
670
671 if (MONO_IS_PHI (ins)) {
672 for (i = ins->inst_phi_args [0]; i > 0; i--) {
673 g_assert (ins->inst_phi_args [i] != -1);
674 record_use (cfg, get_vreg_to_inst (cfg, ins->inst_phi_args [i]), bb, ins);
675 }
676 }
677
678 /* DREG */
679 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
680 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
681
682 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
683 info = MONO_VARINFO (cfg, var->inst_c0);
684 info->def = ins;
685 info->def_bb = bb;
686 }
687 }
688 }
689 }
690
691 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
692 }
693
694 static void
695 mono_ssa_copyprop (MonoCompile *cfg)
696 {
697 int i, index;
698 GList *l;
699
700 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
701
702 for (index = 0; index < cfg->num_varinfo; ++index) {
703 MonoInst *var = cfg->varinfo [index];
704 MonoMethodVar *info = MONO_VARINFO (cfg, index);
705
706 if (info->def && (MONO_IS_MOVE (info->def))) {
707 MonoInst *var2 = get_vreg_to_inst (cfg, info->def->sreg1);
708
709 if (var2 && !(var2->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)) && MONO_VARINFO (cfg, var2->inst_c0)->def && (!MONO_IS_PHI (MONO_VARINFO (cfg, var2->inst_c0)->def))) {
710 /* Rewrite all uses of var to be uses of var2 */
711 int dreg = var->dreg;
712 int sreg1 = var2->dreg;
713 const char *spec;
714
715 l = info->uses;
716 while (l) {
717 MonoVarUsageInfo *u = (MonoVarUsageInfo*)l->data;
718 MonoInst *ins = u->inst;
719 GList *next = l->next;
720
721 spec = INS_INFO (ins->opcode);
722
723 if (spec [MONO_INST_SRC1] != ' ' && ins->sreg1 == dreg) {
724 ins->sreg1 = sreg1;
725 } else if (spec [MONO_INST_SRC2] != ' ' && ins->sreg2 == dreg) {
726 ins->sreg2 = sreg1;
727 } else if (MONO_IS_STORE_MEMBASE (ins) && ins->dreg == dreg) {
728 ins->dreg = sreg1;
729 } else if (MONO_IS_PHI (ins)) {
730 for (i = ins->inst_phi_args [0]; i > 0; i--) {
731 int sreg = ins->inst_phi_args [i];
732 if (sreg == var->dreg)
733 break;
734 }
735 g_assert (i > 0);
736 ins->inst_phi_args [i] = sreg1;
737 }
738 else
739 g_assert_not_reached ();
740
741 record_use (cfg, var2, u->bb, ins);
742
743 l = next;
744 }
745
746 info->uses = NULL;
747 }
748 }
749 }
750
751 if (cfg->verbose_level >= 4) {
752 MonoBasicBlock *bb;
753
754 for (bb = cfg->bb_entry; bb; bb = bb->next_bb)
755 mono_print_bb (bb, "AFTER SSA COPYPROP");
756 }
757 }
758
759 static int
760 evaluate_ins (MonoCompile *cfg, MonoInst *ins, MonoInst **res, MonoInst **carray)
761 {
762 MonoInst *arg0, *arg1, *c0;
763 int r1, r2;
764 gboolean const_args = FALSE;
765 const char *spec = INS_INFO (ins->opcode);
766
767 /* Short-circuit this */
768 if (ins->opcode == OP_ICONST) {
769 *res = ins;
770 return 1;
771 }
772
773 if (ins->opcode == OP_NOP)
774 return 2;
775
776 arg0 = NULL;
777 if (spec [MONO_INST_SRC1] != ' ') {
778 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg1);
779
780 r1 = 2;
781 arg0 = carray [ins->sreg1];
782 if (arg0)
783 r1 = 1;
784 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
785 r1 = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
786 } else {
787 r1 = 2;
788 }
789
790 arg1 = NULL;
791 if (spec [MONO_INST_SRC2] != ' ') {
792 MonoInst *var = get_vreg_to_inst (cfg, ins->sreg2);
793
794 r2 = 2;
795 arg1 = carray [ins->sreg2];
796 if (arg1)
797 r2 = 1;
798 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
799 r2 = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
800 }
801 else {
802 r2 = 0;
803 }
804
805 c0 = NULL;
806 if ((spec [MONO_INST_SRC1] != ' ') && (spec [MONO_INST_SRC2] != ' ')) {
807 /* Binop */
808 const_args = (r1 == 1) && (r2 == 1);
809 }
810 else if (spec [MONO_INST_SRC1] != ' ') {
811 /* Unop */
812 const_args = (r1 == 1);
813 }
814
815 if (const_args) {
816 if ((spec [MONO_INST_DEST] != ' ') && carray [ins->dreg]) {
817 // Cached value
818 *res = carray [ins->dreg];
819 return 1;
820 }
821 c0 = mono_constant_fold_ins2 (cfg, ins, arg0, arg1, FALSE);
822 if (c0) {
823 if (G_UNLIKELY (cfg->verbose_level > 1)) {
824 printf ("\t cfold -> ");
825 mono_print_ins (c0);
826 }
827 *res = c0;
828 return 1;
829 }
830 else
831 /* Can't cfold this ins */
832 return 2;
833 }
834
835 if ((spec [MONO_INST_SRC1] != ' ') && (spec [MONO_INST_SRC2] != ' ')) {
836 /* Binop */
837 if ((r1 == 2) || (r2 == 2))
838 return 2;
839 else
840 return 0;
841 }
842 else if (spec [MONO_INST_SRC1] != ' ') {
843 /* Unop */
844 if (r1 == 2)
845 return 2;
846 else
847 return 0;
848 }
849 else
850 return 2;
851 }
852
853 static inline void
854 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
855 {
856 if (info->cpstate >= state)
857 return;
858
859 info->cpstate = state;
860
861 if (G_UNLIKELY (cfg->verbose_level > 1))
862 printf ("\tState of R%d set to %d\n", cfg->varinfo [info->idx]->dreg, info->cpstate);
863
864 if (state == 1)
865 g_assert (c0);
866
867 carray [cfg->varinfo [info->idx]->dreg] = c0;
868
869 if (!g_list_find (*cvars, info)) {
870 *cvars = g_list_prepend (*cvars, info);
871 }
872 }
873
874 static inline void
875 add_cprop_bb (MonoCompile *cfg, MonoBasicBlock *bb, GList **bblist)
876 {
877 if (G_UNLIKELY (cfg->verbose_level > 1))
878 printf ("\tAdd BB%d to worklist\n", bb->block_num);
879
880 if (!(bb->flags & BB_REACHABLE)) {
881 bb->flags |= BB_REACHABLE;
882 *bblist = g_list_prepend (*bblist, bb);
883 }
884 }
885
886 static void
887 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GList **cvars, GList **bblist, MonoInst **carray)
888 {
889 const char *spec = INS_INFO (ins->opcode);
890
891 if (ins->opcode == OP_NOP)
892 return;
893
894 if (cfg->verbose_level > 1)
895 mono_print_ins (ins);
896
897 /* FIXME: Support longs/floats */
898 /* FIXME: Work on vregs as well */
899
900 if (MONO_IS_PHI (ins)) {
901 MonoMethodVar *info = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, ins->dreg)->inst_c0);
902 MonoInst *c0 = NULL;
903 int j;
904
905 for (j = 1; j <= ins->inst_phi_args [0]; j++) {
906 MonoInst *var = get_vreg_to_inst (cfg, ins->inst_phi_args [j]);
907 MonoMethodVar *mv = MONO_VARINFO (cfg, var->inst_c0);
908 MonoInst *src = mv->def;
909
910 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE))
911 continue;
912
913 if (!mv->def || !src || mv->cpstate == 2) {
914 change_varstate (cfg, cvars, info, 2, NULL, carray);
915 break;
916 }
917
918 if (mv->cpstate == 0)
919 continue;
920
921 g_assert (carray [var->dreg]);
922
923 if (!c0)
924 c0 = carray [var->dreg];
925
926 /* FIXME: */
927 if (c0->opcode != OP_ICONST) {
928 change_varstate (cfg, cvars, info, 2, NULL, carray);
929 break;
930 }
931
932 if (carray [var->dreg]->inst_c0 != c0->inst_c0) {
933 change_varstate (cfg, cvars, info, 2, NULL, carray);
934 break;
935 }
936 }
937
938 if (c0 && info->cpstate < 1) {
939 change_varstate (cfg, cvars, info, 1, c0, carray);
940
941 g_assert (c0->opcode == OP_ICONST);
942 }
943 }
944 else if (!MONO_IS_STORE_MEMBASE (ins) && ((spec [MONO_INST_SRC1] != ' ') || (spec [MONO_INST_SRC2] != ' ') || (spec [MONO_INST_DEST] != ' '))) {
945 MonoInst *var, *c0;
946 int state;
947
948 if (spec [MONO_INST_DEST] != ' ')
949 var = get_vreg_to_inst (cfg, ins->dreg);
950 else
951 var = NULL;
952
953 c0 = NULL;
954 state = evaluate_ins (cfg, ins, &c0, carray);
955
956 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
957 MonoMethodVar *info = MONO_VARINFO (cfg, var->inst_c0);
958
959 if (info->cpstate < 2) {
960 if (state == 1)
961 change_varstate (cfg, cvars, info, 1, c0, carray);
962 else if (state == 2)
963 change_varstate (cfg, cvars, info, 2, NULL, carray);
964 }
965 }
966 else if (!var && (ins->dreg != -1)) {
967 /*
968 * We don't record def-use information for local vregs since it would be
969 * expensive. Instead, we depend on the fact that all uses of the vreg are in
970 * the same bblock, so they will be examined after the definition.
971 * FIXME: This isn't true if the ins is visited through an SSA edge.
972 */
973 if (c0) {
974 carray [ins->dreg] = c0;
975 } else {
976 if (carray [ins->dreg]) {
977 /*
978 * The state of the vreg changed from constant to non-constant
979 * -> need to rescan the whole bblock.
980 */
981 carray [ins->dreg] = NULL;
982 /* FIXME: Speed this up */
983
984 if (!g_list_find (*bblist, bb))
985 *bblist = g_list_prepend (*bblist, bb);
986 }
987 }
988 }
989
990 if (ins->opcode == OP_JUMP_TABLE) {
991 int i;
992 MonoJumpInfoBBTable *table = ins->inst_p0;
993
994 if (ins->next->opcode != OP_PADD) {
995 /* The PADD was optimized away */
996 /* FIXME: handle this as well */
997 for (i = 0; i < table->table_size; i++)
998 if (table->table [i])
999 add_cprop_bb (cfg, table->table [i], bblist);
1000 return;
1001 }
1002
1003 g_assert (ins->next->opcode == OP_PADD);
1004 g_assert (ins->next->sreg1 == ins->dreg);
1005
1006 if (carray [ins->next->sreg2]) {
1007 #if SIZEOF_VOID_P == 8
1008 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1009 #else
1010 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1011 #endif
1012 if ((idx < 0) || (idx >= table->table_size))
1013 /* Out-of-range, no branch is executed */
1014 return;
1015 else
1016 if (table->table [idx])
1017 add_cprop_bb (cfg, table->table [idx], bblist);
1018 }
1019 else {
1020 for (i = 0; i < table->table_size; i++)
1021 if (table->table [i])
1022 add_cprop_bb (cfg, table->table [i], bblist);
1023 }
1024 }
1025
1026 if (ins->opcode == OP_SWITCH) {
1027 int i;
1028 MonoJumpInfoBBTable *table = ins->inst_p0;
1029
1030 for (i = 0; i < table->table_size; i++)
1031 if (table->table [i])
1032 add_cprop_bb (cfg, table->table [i], bblist);
1033 }
1034
1035 /* Handle COMPARE+BRCOND pairs */
1036 if (ins->next && MONO_IS_COND_BRANCH_OP (ins->next)) {
1037 if (c0) {
1038 g_assert (c0->opcode == OP_ICONST);
1039
1040 if (c0->inst_c0)
1041 ins->next->flags |= MONO_INST_CFOLD_TAKEN;
1042 else
1043 ins->next->flags |= MONO_INST_CFOLD_NOT_TAKEN;
1044 }
1045 else {
1046 ins->next->flags &= ~(MONO_INST_CFOLD_TAKEN | MONO_INST_CFOLD_NOT_TAKEN);
1047 }
1048
1049 visit_inst (cfg, bb, ins->next, cvars, bblist, carray);
1050 }
1051 } else if (ins->opcode == OP_BR) {
1052 add_cprop_bb (cfg, ins->inst_target_bb, bblist);
1053 } else if (MONO_IS_COND_BRANCH_OP (ins)) {
1054 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1055 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1056 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1057 if (ins->inst_false_bb)
1058 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1059 } else {
1060 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1061 if (ins->inst_false_bb)
1062 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1063 }
1064 }
1065 }
1066
1067 /**
1068 * fold_ins:
1069 *
1070 * Replace INS with its constant value, if it exists
1071 */
1072 static void
1073 fold_ins (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, MonoInst **carray)
1074 {
1075 const char *spec = INS_INFO (ins->opcode);
1076 int opcode2;
1077
1078 if ((ins->opcode != OP_NOP) && (ins->dreg != -1) && !MONO_IS_STORE_MEMBASE (ins)) {
1079 if (carray [ins->dreg] && (spec [MONO_INST_DEST] == 'i') && (ins->dreg >= MONO_MAX_IREGS)) {
1080 /* Perform constant folding */
1081 /* FIXME: */
1082 g_assert (carray [ins->dreg]->opcode == OP_ICONST);
1083 ins->opcode = OP_ICONST;
1084 ins->inst_c0 = carray [ins->dreg]->inst_c0;
1085 ins->sreg1 = ins->sreg2 = -1;
1086 }
1087 else if ((spec [MONO_INST_SRC2] != ' ') && carray [ins->sreg2]) {
1088 /* Perform op->op_imm conversion */
1089 opcode2 = mono_op_to_op_imm (ins->opcode);
1090 if (opcode2 != -1) {
1091 ins->opcode = opcode2;
1092 ins->inst_imm = carray [ins->sreg2]->inst_c0;
1093 ins->sreg2 = -1;
1094
1095 if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
1096 ((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
1097 }
1098 }
1099
1100 if (ins->opcode == OP_JUMP_TABLE) {
1101 int i;
1102 MonoJumpInfoBBTable *table = ins->inst_p0;
1103
1104 if (ins->next->opcode != OP_PADD) {
1105 /* The PADD was optimized away */
1106 /* FIXME: handle this as well */
1107 return;
1108 }
1109
1110 g_assert (ins->next->opcode == OP_PADD);
1111 g_assert (ins->next->sreg1 == ins->dreg);
1112 g_assert (ins->next->next->opcode == OP_LOAD_MEMBASE);
1113
1114 if (carray [ins->next->sreg2]) {
1115 /* Convert to a simple branch */
1116 #if SIZEOF_VOID_P == 8
1117 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1118 #else
1119 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1120 #endif
1121
1122 if (!((idx >= 0) && (idx < table->table_size))) {
1123 /* Out of range, eliminate the whole switch */
1124 for (i = 0; i < table->table_size; ++i) {
1125 remove_bb_from_phis (cfg, bb, table->table [i]);
1126 mono_unlink_bblock (cfg, bb, table->table [i]);
1127 }
1128
1129 NULLIFY_INS (ins);
1130 NULLIFY_INS (ins->next);
1131 NULLIFY_INS (ins->next->next);
1132 if (ins->next->next->next)
1133 NULLIFY_INS (ins->next->next->next);
1134
1135 return;
1136 }
1137
1138 if (!ins->next->next->next || ins->next->next->next->opcode != OP_BR_REG) {
1139 /* A one-way switch which got optimized away */
1140 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1141 printf ("\tNo cfold on ");
1142 mono_print_ins (ins);
1143 }
1144 return;
1145 }
1146
1147 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1148 printf ("\tcfold on ");
1149 mono_print_ins (ins);
1150 }
1151
1152 /* Unlink target bblocks */
1153 for (i = 0; i < table->table_size; ++i) {
1154 if (i != idx) {
1155 remove_bb_from_phis (cfg, bb, table->table [i]);
1156 mono_unlink_bblock (cfg, bb, table->table [i]);
1157 }
1158 }
1159
1160 /* Change the OP_BR_REG to a simple branch */
1161 ins->next->next->next->opcode = OP_BR;
1162 ins->next->next->next->inst_target_bb = table->table [idx];
1163 ins->next->next->next->sreg1 = -1;
1164
1165 /* Nullify the other instructions */
1166 NULLIFY_INS (ins);
1167 NULLIFY_INS (ins->next);
1168 NULLIFY_INS (ins->next->next);
1169 }
1170 }
1171 }
1172 else if (MONO_IS_COND_BRANCH_OP (ins)) {
1173 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1174 remove_bb_from_phis (cfg, bb, ins->inst_false_bb);
1175 mono_unlink_bblock (cfg, bb, ins->inst_false_bb);
1176 ins->opcode = OP_BR;
1177 ins->inst_target_bb = ins->inst_true_bb;
1178 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1179 remove_bb_from_phis (cfg, bb, ins->inst_true_bb);
1180 mono_unlink_bblock (cfg, bb, ins->inst_true_bb);
1181 ins->opcode = OP_BR;
1182 ins->inst_target_bb = ins->inst_false_bb;
1183 }
1184 }
1185 }
1186
1187 void
1188 mono_ssa_cprop2 (MonoCompile *cfg)
1189 {
1190 MonoInst **carray;
1191 MonoBasicBlock *bb;
1192 GList *bblock_list, *cvars;
1193 GList *tmp;
1194 int i;
1195 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1196
1197 carray = g_new0 (MonoInst*, cfg->next_vreg);
1198
1199 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1200 mono_ssa_create_def_use (cfg);
1201
1202 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1203 cfg->bb_entry->flags |= BB_REACHABLE;
1204
1205 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1206
1207 for (i = 0; i < cfg->num_varinfo; i++) {
1208 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1209 if (!info->def)
1210 info->cpstate = 2;
1211 }
1212
1213 cvars = NULL;
1214
1215 while (bblock_list) {
1216 MonoInst *inst;
1217
1218 bb = (MonoBasicBlock *)bblock_list->data;
1219
1220 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1221
1222 g_assert (bb->flags & BB_REACHABLE);
1223
1224 if (bb->out_count == 1) {
1225 if (!(bb->out_bb [0]->flags & BB_REACHABLE)) {
1226 bb->out_bb [0]->flags |= BB_REACHABLE;
1227 bblock_list = g_list_prepend (bblock_list, bb->out_bb [0]);
1228 }
1229 }
1230
1231 if (cfg->verbose_level > 1)
1232 printf ("\nSSA CONSPROP BB%d:\n", bb->block_num);
1233
1234 for (inst = bb->code; inst; inst = inst->next) {
1235 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1236 }
1237
1238 while (cvars) {
1239 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1240 cvars = g_list_delete_link (cvars, cvars);
1241
1242 for (tmp = info->uses; tmp; tmp = tmp->next) {
1243 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1244 if (!(ui->bb->flags & BB_REACHABLE))
1245 continue;
1246 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1247 }
1248 }
1249 }
1250
1251 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1252 MonoInst *inst;
1253 for (inst = bb->code; inst; inst = inst->next) {
1254 fold_ins (cfg, bb, inst, carray);
1255 }
1256 }
1257
1258 g_free (carray);
1259
1260 cfg->comp_done |= MONO_COMP_REACHABILITY;
1261
1262 /* fixme: we should update usage infos during cprop, instead of computing it again */
1263 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1264 for (i = 0; i < cfg->num_varinfo; i++) {
1265 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1266 info->def = NULL;
1267 info->uses = NULL;
1268 }
1269 }
1270
1271 static inline void
1272 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1273 {
1274 GList *tmp;
1275
1276 *wl = g_list_prepend_mempool (cfg->mempool, *wl, use);
1277
1278 for (tmp = use->uses; tmp; tmp = tmp->next) {
1279 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1280 if (ui->inst == var->def) {
1281 /* from the mempool */
1282 use->uses = g_list_remove_link (use->uses, tmp);
1283 break;
1284 }
1285 }
1286 }
1287
1288 void
1289 mono_ssa_deadce2 (MonoCompile *cfg)
1290 {
1291 int i;
1292 GList *work_list;
1293
1294 g_assert (cfg->comp_done & MONO_COMP_SSA);
1295
1296 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1297
1298 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1299 mono_ssa_create_def_use (cfg);
1300
1301 mono_ssa_copyprop (cfg);
1302
1303 work_list = NULL;
1304 for (i = 0; i < cfg->num_varinfo; i++) {
1305 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1306 work_list = g_list_prepend_mempool (cfg->mempool, work_list, info);
1307 }
1308
1309 while (work_list) {
1310 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1311 work_list = g_list_remove_link (work_list, work_list);
1312
1313 /*
1314 * The second part of the condition happens often when PHI nodes have their dreg
1315 * as one of their arguments due to the fact that we use the original vars.
1316 */
1317 if (info->def && (!info->uses || ((info->uses->next == NULL) && (((MonoVarUsageInfo*)info->uses->data)->inst == info->def)))) {
1318 MonoInst *def = info->def;
1319
1320 /* Eliminating FMOVE could screw up the fp stack */
1321 if (MONO_IS_MOVE (def) && (!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE))) {
1322 MonoInst *src_var = get_vreg_to_inst (cfg, def->sreg1);
1323 if (src_var && !(src_var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1324 add_to_dce_worklist (cfg, info, MONO_VARINFO (cfg, src_var->inst_c0), &work_list);
1325 def->opcode = OP_NOP;
1326 def->dreg = def->sreg1 = def->sreg2 = -1;
1327 info->reg = -1;
1328 } else if ((def->opcode == OP_ICONST) || (def->opcode == OP_I8CONST) || MONO_IS_ZERO (def)) {
1329 def->opcode = OP_NOP;
1330 def->dreg = def->sreg1 = def->sreg2 = -1;
1331 info->reg = -1;
1332 } else if (MONO_IS_PHI (def)) {
1333 int j;
1334 for (j = def->inst_phi_args [0]; j > 0; j--) {
1335 MonoMethodVar *u = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, def->inst_phi_args [j])->inst_c0);
1336 add_to_dce_worklist (cfg, info, u, &work_list);
1337 }
1338 def->opcode = OP_NOP;
1339 def->dreg = def->sreg1 = def->sreg2 = -1;
1340 info->reg = -1;
1341 }
1342 else if (def->opcode == OP_NOP) {
1343 }
1344 //else
1345 //mono_print_ins (def);
1346 }
1347
1348 }
1349 }
1350
1351 #if 0
1352 void
1353 mono_ssa_strength_reduction (MonoCompile *cfg)
1354 {
1355 MonoBasicBlock *bb;
1356 int i;
1357
1358 g_assert (cfg->comp_done & MONO_COMP_SSA);
1359 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1360 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1361
1362 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1363 GList *lp = bb->loop_blocks;
1364
1365 if (lp) {
1366 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1367
1368 /* we only consider loops with 2 in bblocks */
1369 if (!h->in_count == 2)
1370 continue;
1371
1372 for (i = 0; i < cfg->num_varinfo; i++) {
1373 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1374
1375 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1376 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1377 MonoInst *v = info->def->inst_i1;
1378
1379
1380 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1381 }
1382 }
1383 }
1384 }
1385 }
1386 #endif
1387
1388 #endif /* DISABLE_JIT */
Mirror of the official Mono project git repository