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[mono-api-info] Use XmlWriter instead of XmlDocument to make this faster.
[mono-project.git] / mono / mini / ssa.c
bloba29108872a4adbb4dfb50430f70595a6eb3c9b17
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 * Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
9 */
10 #include <config.h>
11 #include <string.h>
12 #include <mono/metadata/debug-helpers.h>
13 #include <mono/metadata/mempool.h>
14 #include <mono/metadata/mempool-internals.h>
15
16 #ifndef DISABLE_JIT
17
18 #include "mini.h"
19 #ifdef HAVE_ALLOCA_H
20 #include <alloca.h>
21 #endif
22
23 #define CREATE_PRUNED_SSA
24
25 //#define DEBUG_SSA 1
26
27 #define NEW_PHI(cfg,dest,val) do { \
28 MONO_INST_NEW ((cfg), (dest), OP_PHI); \
29 (dest)->inst_c0 = (val); \
30 } while (0)
31
32 typedef struct {
33 MonoBasicBlock *bb;
34 MonoInst *inst;
35 } MonoVarUsageInfo;
36
37 static void
38 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
39 {
40 int i;
41
42 for (i = 0; i < bb->out_count; i++) {
43 if (bb->out_bb [i] == target) {
44 bb->out_bb [i] = bb->out_bb [--bb->out_count];
45 break;
46 }
47 }
48 for (i = 0; i < target->in_count; i++) {
49 if (target->in_bb [i] == bb) {
50 target->in_bb [i] = target->in_bb [--target->in_count];
51 break;
52
53 }
54 }
55 }
56
57 static void
58 unlink_unused_bblocks (MonoCompile *cfg)
59 {
60 int i, j;
61 MonoBasicBlock *bb;
62
63 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
64
65 if (G_UNLIKELY (cfg->verbose_level > 1))
66 printf ("\nUNLINK UNUSED BBLOCKS:\n");
67
68 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
69 if (!(bb->next_bb->flags & BB_REACHABLE)) {
70 bb->next_bb = bb->next_bb->next_bb;
71 } else
72 bb = bb->next_bb;
73 }
74
75 for (i = 1; i < cfg->num_bblocks; i++) {
76 bb = cfg->bblocks [i];
77
78 if (!(bb->flags & BB_REACHABLE)) {
79 for (j = 0; j < bb->in_count; j++) {
80 unlink_target (bb->in_bb [j], bb);
81 }
82 for (j = 0; j < bb->out_count; j++) {
83 unlink_target (bb, bb->out_bb [j]);
84 }
85 if (G_UNLIKELY (cfg->verbose_level > 1))
86 printf ("\tUnlinked BB%d\n", bb->block_num);
87 }
88
89 }
90 }
91
92 /**
93 * remove_bb_from_phis:
94 *
95 * Remove BB from the PHI statements in TARGET.
96 */
97 static void
98 remove_bb_from_phis (MonoCompile *cfg, MonoBasicBlock *bb, MonoBasicBlock *target)
99 {
100 MonoInst *ins;
101 int i, j;
102
103 for (i = 0; i < target->in_count; i++) {
104 if (target->in_bb [i] == bb) {
105 break;
106 }
107 }
108 g_assert (i < target->in_count);
109
110 for (ins = target->code; ins; ins = ins->next) {
111 if (MONO_IS_PHI (ins)) {
112 for (j = i; j < ins->inst_phi_args [0] - 1; ++j)
113 ins->inst_phi_args [j + 1] = ins->inst_phi_args [j + 2];
114 ins->inst_phi_args [0] --;
115 }
116 else
117 break;
118 }
119 }
120
121 static inline int
122 op_phi_to_move (int opcode)
123 {
124 switch (opcode) {
125 case OP_PHI:
126 return OP_MOVE;
127 case OP_FPHI:
128 return OP_FMOVE;
129 case OP_VPHI:
130 return OP_VMOVE;
131 case OP_XPHI:
132 return OP_XMOVE;
133 default:
134 g_assert_not_reached ();
135 }
136
137 return -1;
138 }
139
140 static inline void
141 record_use (MonoCompile *cfg, MonoInst *var, MonoBasicBlock *bb, MonoInst *ins)
142 {
143 MonoMethodVar *info;
144 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
145
146 info = MONO_VARINFO (cfg, var->inst_c0);
147
148 ui->bb = bb;
149 ui->inst = ins;
150 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
151 }
152
153 typedef struct {
154 MonoInst *var;
155 int idx;
156 } RenameInfo;
157
158 /**
159 * mono_ssa_rename_vars:
160 *
161 * Implement renaming of SSA variables. Also compute def-use information in parallel.
162 * @stack_history points to an area of memory which can be used for storing changes
163 * made to the stack, so they can be reverted later.
164 */
165 static void
166 mono_ssa_rename_vars (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)
167 {
168 MonoInst *ins, *new_var;
169 int i, j, idx;
170 GSList *tmp;
171 int stack_history_len = 0;
172
173 if (cfg->verbose_level >= 4)
174 printf ("\nRENAME VARS BLOCK %d:\n", bb->block_num);
175
176 /* First pass: Create new vars */
177 for (ins = bb->code; ins; ins = ins->next) {
178 const char *spec = INS_INFO (ins->opcode);
179 int num_sregs;
180 int sregs [MONO_MAX_SRC_REGS];
181
182 #ifdef DEBUG_SSA
183 printf ("\tProcessing "); mono_print_ins (ins);
184 #endif
185 if (ins->opcode == OP_NOP)
186 continue;
187
188 /* SREGs */
189 num_sregs = mono_inst_get_src_registers (ins, sregs);
190 for (i = 0; i < num_sregs; ++i) {
191 if (spec [MONO_INST_SRC1 + i] != ' ') {
192 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
193 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
194 int idx = var->inst_c0;
195 if (stack [idx]) {
196 if (var->opcode != OP_ARG)
197 g_assert (stack [idx]);
198 sregs [i] = stack [idx]->dreg;
199 record_use (cfg, stack [idx], bb, ins);
200 }
201 else
202 record_use (cfg, var, bb, ins);
203 }
204 else if (G_UNLIKELY (!var && lvreg_stack [sregs [i]]))
205 sregs [i] = lvreg_stack [sregs [i]];
206 }
207 }
208 mono_inst_set_src_registers (ins, sregs);
209
210 if (MONO_IS_STORE_MEMBASE (ins)) {
211 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
212 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
213 int idx = var->inst_c0;
214 if (stack [idx]) {
215 if (var->opcode != OP_ARG)
216 g_assert (stack [idx]);
217 ins->dreg = stack [idx]->dreg;
218 record_use (cfg, stack [idx], bb, ins);
219 }
220 else
221 record_use (cfg, var, bb, ins);
222 }
223 else if (G_UNLIKELY (!var && lvreg_stack [ins->dreg]))
224 ins->dreg = lvreg_stack [ins->dreg];
225 }
226
227 /* DREG */
228 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
229 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
230 MonoMethodVar *info;
231
232 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
233 idx = var->inst_c0;
234 g_assert (idx < max_vars);
235
236 if (var->opcode == OP_ARG)
237 originals_used [idx] = TRUE;
238
239 /* FIXME: */
240 g_assert (stack_history_len < stack_history_size);
241 stack_history [stack_history_len].var = stack [idx];
242 stack_history [stack_history_len].idx = idx;
243 stack_history_len ++;
244
245 if (originals_used [idx]) {
246 new_var = mono_compile_create_var (cfg, var->inst_vtype, OP_LOCAL);
247 new_var->flags = var->flags;
248 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
249
250 if (cfg->verbose_level >= 4)
251 printf (" R%d -> R%d\n", var->dreg, new_var->dreg);
252
253 stack [idx] = new_var;
254
255 ins->dreg = new_var->dreg;
256 var = new_var;
257 }
258 else {
259 stack [idx] = var;
260 originals_used [idx] = TRUE;
261 }
262
263 info = MONO_VARINFO (cfg, var->inst_c0);
264 info->def = ins;
265 info->def_bb = bb;
266 }
267 else if (G_UNLIKELY (!var && lvreg_defined [ins->dreg] && (ins->dreg >= MONO_MAX_IREGS))) {
268 /* Perform renaming for local vregs */
269 lvreg_stack [ins->dreg] = vreg_is_ref (cfg, ins->dreg) ? mono_alloc_ireg_ref (cfg) : mono_alloc_preg (cfg);
270 ins->dreg = lvreg_stack [ins->dreg];
271 }
272 else
273 lvreg_defined [ins->dreg] = TRUE;
274 }
275
276 #ifdef DEBUG_SSA
277 printf ("\tAfter processing "); mono_print_ins (ins);
278 #endif
279
280 }
281
282 /* Rename PHI arguments in succeeding bblocks */
283 for (i = 0; i < bb->out_count; i++) {
284 MonoBasicBlock *n = bb->out_bb [i];
285
286 for (j = 0; j < n->in_count; j++)
287 if (n->in_bb [j] == bb)
288 break;
289
290 for (ins = n->code; ins; ins = ins->next) {
291 if (MONO_IS_PHI (ins)) {
292 idx = ins->inst_c0;
293 if (stack [idx])
294 new_var = stack [idx];
295 else
296 new_var = cfg->varinfo [idx];
297 #ifdef DEBUG_SSA
298 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
299 #endif
300 ins->inst_phi_args [j + 1] = new_var->dreg;
301 record_use (cfg, new_var, n, ins);
302 if (G_UNLIKELY (cfg->verbose_level >= 4))
303 printf ("\tAdd PHI R%d <- R%d to BB%d\n", ins->dreg, new_var->dreg, n->block_num);
304 }
305 else
306 /* The phi nodes are at the beginning of the bblock */
307 break;
308 }
309 }
310
311 if (bb->dominated) {
312 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
313 mono_ssa_rename_vars (cfg, max_vars, (MonoBasicBlock *)tmp->data, originals_used, stack, lvreg_stack, lvreg_defined, stack_history + stack_history_len, stack_history_size - stack_history_len);
314 }
315 }
316
317 /* Restore stack */
318 for (i = stack_history_len - 1; i >= 0; i--) {
319 stack [stack_history [i].idx] = stack_history [i].var;
320 }
321
322 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
323 }
324
325 void
326 mono_ssa_compute (MonoCompile *cfg)
327 {
328 int i, j, idx, bitsize;
329 MonoBitSet *set;
330 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
331 MonoInst *ins, **stack;
332 guint8 *buf, *buf_start;
333 RenameInfo *stack_history;
334 int stack_history_size;
335 gboolean *originals;
336 guint32 *lvreg_stack;
337 gboolean *lvreg_defined;
338
339 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
340
341 g_assert (!cfg->disable_ssa);
342
343 if (cfg->verbose_level >= 4)
344 printf ("\nCOMPUTE SSA %d (R%d-)\n\n", cfg->num_varinfo, cfg->next_vreg);
345
346 #ifdef CREATE_PRUNED_SSA
347 /* we need liveness for pruned SSA */
348 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
349 mono_analyze_liveness (cfg);
350 #endif
351
352 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
353
354 bitsize = mono_bitset_alloc_size (cfg->num_bblocks, 0);
355 buf = buf_start = (guint8 *)g_malloc0 (mono_bitset_alloc_size (cfg->num_bblocks, 0) * cfg->num_varinfo);
356
357 for (i = 0; i < cfg->num_varinfo; ++i) {
358 vinfo [i].def_in = mono_bitset_mem_new (buf, cfg->num_bblocks, 0);
359 buf += bitsize;
360 vinfo [i].idx = i;
361 /* implicit reference at start */
362 if (cfg->varinfo [i]->opcode == OP_ARG)
363 mono_bitset_set_fast (vinfo [i].def_in, 0);
364 }
365
366 for (i = 0; i < cfg->num_bblocks; ++i) {
367 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], ins) {
368 if (ins->opcode == OP_NOP)
369 continue;
370
371 if (!MONO_IS_STORE_MEMBASE (ins) && get_vreg_to_inst (cfg, ins->dreg)) {
372 mono_bitset_set_fast (vinfo [get_vreg_to_inst (cfg, ins->dreg)->inst_c0].def_in, i);
373 }
374 }
375 }
376
377 /* insert phi functions */
378 for (i = 0; i < cfg->num_varinfo; ++i) {
379 MonoInst *var = cfg->varinfo [i];
380
381 #if SIZEOF_REGISTER == 4
382 if (var->type == STACK_I8 && !COMPILE_LLVM (cfg))
383 continue;
384 #endif
385 if (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))
386 continue;
387
388 /* Most variables have only one definition */
389 if (mono_bitset_count (vinfo [i].def_in) <= 1)
390 continue;
391
392 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
393
394 if (cfg->verbose_level >= 4) {
395 if (mono_bitset_count (set) > 0) {
396 printf ("\tR%d needs PHI functions in ", var->dreg);
397 mono_blockset_print (cfg, set, "", -1);
398 }
399 }
400
401 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
402 MonoBasicBlock *bb = cfg->bblocks [idx];
403
404 /* fixme: create pruned SSA? we would need liveness information for that */
405
406 if (bb == cfg->bb_exit && !COMPILE_LLVM (cfg))
407 continue;
408
409 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
410 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
411 continue;
412 }
413
414 NEW_PHI (cfg, ins, i);
415
416 switch (var->type) {
417 case STACK_I4:
418 case STACK_I8:
419 case STACK_PTR:
420 case STACK_MP:
421 case STACK_OBJ:
422 ins->opcode = OP_PHI;
423 break;
424 case STACK_R8:
425 ins->opcode = OP_FPHI;
426 break;
427 case STACK_VTYPE:
428 ins->opcode = MONO_CLASS_IS_SIMD (cfg, var->klass) ? OP_XPHI : OP_VPHI;
429 break;
430 }
431
432 if (var->inst_vtype->byref)
433 ins->klass = mono_defaults.int_class;
434 else
435 ins->klass = var->klass;
436
437 ins->inst_phi_args = (int *)mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
438 ins->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
439
440 /* For debugging */
441 for (j = 0; j < cfg->bblocks [idx]->in_count; ++j)
442 ins->inst_phi_args [j + 1] = -1;
443
444 ins->dreg = cfg->varinfo [i]->dreg;
445
446 mono_bblock_insert_before_ins (bb, bb->code, ins);
447
448 #ifdef DEBUG_SSA
449 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
450 #endif
451 }
452 }
453
454 /* free the stuff */
455 g_free (vinfo);
456 g_free (buf_start);
457
458 /* Renaming phase */
459
460 stack = (MonoInst **)alloca (sizeof (MonoInst *) * cfg->num_varinfo);
461 memset (stack, 0, sizeof (MonoInst *) * cfg->num_varinfo);
462
463 lvreg_stack = g_new0 (guint32, cfg->next_vreg);
464 lvreg_defined = g_new0 (gboolean, cfg->next_vreg);
465 stack_history_size = 10240;
466 stack_history = g_new (RenameInfo, stack_history_size);
467 originals = g_new0 (gboolean, cfg->num_varinfo);
468 mono_ssa_rename_vars (cfg, cfg->num_varinfo, cfg->bb_entry, originals, stack, lvreg_stack, lvreg_defined, stack_history, stack_history_size);
469 g_free (stack_history);
470 g_free (originals);
471 g_free (lvreg_stack);
472 g_free (lvreg_defined);
473
474 if (cfg->verbose_level >= 4)
475 printf ("\nEND COMPUTE SSA.\n\n");
476
477 cfg->comp_done |= MONO_COMP_SSA;
478 }
479
480 /*
481 * mono_ssa_remove_gsharedvt:
482 *
483 * Same as mono_ssa_remove, but only remove phi nodes for gsharedvt variables.
484 */
485 void
486 mono_ssa_remove_gsharedvt (MonoCompile *cfg)
487 {
488 MonoInst *ins, *var, *move;
489 int i, j, first;
490
491 /*
492 * When compiling gsharedvt code, we need to get rid of the VPHI instructions,
493 * since they cannot be handled later in the llvm backend.
494 */
495 g_assert (cfg->comp_done & MONO_COMP_SSA);
496
497 for (i = 0; i < cfg->num_bblocks; ++i) {
498 MonoBasicBlock *bb = cfg->bblocks [i];
499
500 if (cfg->verbose_level >= 4)
501 printf ("\nREMOVE SSA %d:\n", bb->block_num);
502
503 for (ins = bb->code; ins; ins = ins->next) {
504 if (!(MONO_IS_PHI (ins) && ins->opcode == OP_VPHI && mini_is_gsharedvt_variable_type (&ins->klass->byval_arg)))
505 continue;
506
507 g_assert (ins->inst_phi_args [0] == bb->in_count);
508 var = get_vreg_to_inst (cfg, ins->dreg);
509
510 /* Check for PHI nodes where all the inputs are the same */
511 first = ins->inst_phi_args [1];
512
513 for (j = 1; j < bb->in_count; ++j)
514 if (first != ins->inst_phi_args [j + 1])
515 break;
516
517 if ((bb->in_count > 1) && (j == bb->in_count)) {
518 ins->opcode = op_phi_to_move (ins->opcode);
519 if (ins->opcode == OP_VMOVE)
520 g_assert (ins->klass);
521 ins->sreg1 = first;
522 } else {
523 for (j = 0; j < bb->in_count; j++) {
524 MonoBasicBlock *pred = bb->in_bb [j];
525 int sreg = ins->inst_phi_args [j + 1];
526
527 if (cfg->verbose_level >= 4)
528 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
529 if (var->dreg != sreg) {
530 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
531 if (move->opcode == OP_VMOVE) {
532 g_assert (ins->klass);
533 move->klass = ins->klass;
534 }
535 move->dreg = var->dreg;
536 move->sreg1 = sreg;
537 mono_add_ins_to_end (pred, move);
538 }
539 }
540
541 NULLIFY_INS (ins);
542 }
543 }
544 }
545 }
546
547 void
548 mono_ssa_remove (MonoCompile *cfg)
549 {
550 MonoInst *ins, *var, *move;
551 int bbindex, i, j, first;
552
553 g_assert (cfg->comp_done & MONO_COMP_SSA);
554
555 for (i = 0; i < cfg->num_bblocks; ++i) {
556 MonoBasicBlock *bb = cfg->bblocks [i];
557
558 if (cfg->verbose_level >= 4)
559 printf ("\nREMOVE SSA %d:\n", bb->block_num);
560
561 for (ins = bb->code; ins; ins = ins->next) {
562 if (MONO_IS_PHI (ins)) {
563 g_assert (ins->inst_phi_args [0] == bb->in_count);
564 var = get_vreg_to_inst (cfg, ins->dreg);
565
566 /* Check for PHI nodes where all the inputs are the same */
567 first = ins->inst_phi_args [1];
568
569 for (j = 1; j < bb->in_count; ++j)
570 if (first != ins->inst_phi_args [j + 1])
571 break;
572
573 if ((bb->in_count > 1) && (j == bb->in_count)) {
574 ins->opcode = op_phi_to_move (ins->opcode);
575 if (ins->opcode == OP_VMOVE)
576 g_assert (ins->klass);
577 ins->sreg1 = first;
578 } else {
579 for (j = 0; j < bb->in_count; j++) {
580 MonoBasicBlock *pred = bb->in_bb [j];
581 int sreg = ins->inst_phi_args [j + 1];
582
583 if (cfg->verbose_level >= 4)
584 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
585 if (var->dreg != sreg) {
586 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
587 if (move->opcode == OP_VMOVE) {
588 g_assert (ins->klass);
589 move->klass = ins->klass;
590 }
591 move->dreg = var->dreg;
592 move->sreg1 = sreg;
593 mono_add_ins_to_end (pred, move);
594 }
595 }
596
597 NULLIFY_INS (ins);
598 }
599 }
600 }
601 }
602
603 if (cfg->verbose_level >= 4) {
604 for (i = 0; i < cfg->num_bblocks; ++i) {
605 MonoBasicBlock *bb = cfg->bblocks [i];
606
607 mono_print_bb (bb, "AFTER REMOVE SSA:");
608 }
609 }
610
611 /*
612 * Removal of SSA form introduces many copies. To avoid this, we tyry to coalesce
613 * the variables if possible. Since the newly introduced SSA variables don't
614 * have overlapping live ranges (because we don't do agressive optimization), we
615 * can coalesce them into the original variable.
616 */
617
618 for (bbindex = 0; bbindex < cfg->num_bblocks; ++bbindex) {
619 MonoBasicBlock *bb = cfg->bblocks [bbindex];
620
621 for (ins = bb->code; ins; ins = ins->next) {
622 const char *spec = INS_INFO (ins->opcode);
623 int num_sregs;
624 int sregs [MONO_MAX_SRC_REGS];
625
626 if (ins->opcode == OP_NOP)
627 continue;
628
629 if (spec [MONO_INST_DEST] != ' ') {
630 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
631
632 if (var) {
633 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
634
635 /*
636 * The third condition avoids coalescing with variables eliminated
637 * during deadce.
638 */
639 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
640 printf ("COALESCE: R%d -> R%d\n", ins->dreg, cfg->varinfo [vmv->reg]->dreg);
641 ins->dreg = cfg->varinfo [vmv->reg]->dreg;
642 }
643 }
644 }
645
646 num_sregs = mono_inst_get_src_registers (ins, sregs);
647 for (i = 0; i < num_sregs; ++i) {
648 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
649
650 if (var) {
651 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
652
653 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
654 printf ("COALESCE: R%d -> R%d\n", sregs [i], cfg->varinfo [vmv->reg]->dreg);
655 sregs [i] = cfg->varinfo [vmv->reg]->dreg;
656 }
657 }
658 }
659 mono_inst_set_src_registers (ins, sregs);
660 }
661 }
662
663 for (i = 0; i < cfg->num_varinfo; ++i) {
664 MONO_VARINFO (cfg, i)->reg = -1;
665 }
666
667 if (cfg->comp_done & MONO_COMP_REACHABILITY)
668 unlink_unused_bblocks (cfg);
669
670 cfg->comp_done &= ~MONO_COMP_LIVENESS;
671
672 cfg->comp_done &= ~MONO_COMP_SSA;
673 }
674
675 static void
676 mono_ssa_create_def_use (MonoCompile *cfg)
677 {
678 MonoBasicBlock *bb;
679 MonoInst *ins;
680 int i;
681
682 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
683
684 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
685 for (ins = bb->code; ins; ins = ins->next) {
686 const char *spec = INS_INFO (ins->opcode);
687 MonoMethodVar *info;
688 int num_sregs;
689 int sregs [MONO_MAX_SRC_REGS];
690
691 if (ins->opcode == OP_NOP)
692 continue;
693
694 /* SREGs */
695 num_sregs = mono_inst_get_src_registers (ins, sregs);
696 for (i = 0; i < num_sregs; ++i) {
697 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
698 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
699 record_use (cfg, var, bb, ins);
700 }
701
702 if (MONO_IS_STORE_MEMBASE (ins)) {
703 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
704 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
705 record_use (cfg, var, bb, ins);
706 }
707
708 if (MONO_IS_PHI (ins)) {
709 for (i = ins->inst_phi_args [0]; i > 0; i--) {
710 g_assert (ins->inst_phi_args [i] != -1);
711 record_use (cfg, get_vreg_to_inst (cfg, ins->inst_phi_args [i]), bb, ins);
712 }
713 }
714
715 /* DREG */
716 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
717 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
718
719 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
720 info = MONO_VARINFO (cfg, var->inst_c0);
721 info->def = ins;
722 info->def_bb = bb;
723 }
724 }
725 }
726 }
727
728 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
729 }
730
731 static void
732 mono_ssa_copyprop (MonoCompile *cfg)
733 {
734 int i, index;
735 GList *l;
736
737 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
738
739 for (index = 0; index < cfg->num_varinfo; ++index) {
740 MonoInst *var = cfg->varinfo [index];
741 MonoMethodVar *info = MONO_VARINFO (cfg, index);
742
743 if (info->def && (MONO_IS_MOVE (info->def))) {
744 MonoInst *var2 = get_vreg_to_inst (cfg, info->def->sreg1);
745
746 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))) {
747 /* Rewrite all uses of var to be uses of var2 */
748 int dreg = var->dreg;
749 int sreg1 = var2->dreg;
750
751 l = info->uses;
752 while (l) {
753 MonoVarUsageInfo *u = (MonoVarUsageInfo*)l->data;
754 MonoInst *ins = u->inst;
755 GList *next = l->next;
756 int num_sregs;
757 int sregs [MONO_MAX_SRC_REGS];
758
759 num_sregs = mono_inst_get_src_registers (ins, sregs);
760 for (i = 0; i < num_sregs; ++i) {
761 if (sregs [i] == dreg)
762 break;
763 }
764 if (i < num_sregs) {
765 g_assert (sregs [i] == dreg);
766 sregs [i] = sreg1;
767 mono_inst_set_src_registers (ins, sregs);
768 } else if (MONO_IS_STORE_MEMBASE (ins) && ins->dreg == dreg) {
769 ins->dreg = sreg1;
770 } else if (MONO_IS_PHI (ins)) {
771 for (i = ins->inst_phi_args [0]; i > 0; i--) {
772 int sreg = ins->inst_phi_args [i];
773 if (sreg == var->dreg)
774 break;
775 }
776 g_assert (i > 0);
777 ins->inst_phi_args [i] = sreg1;
778 }
779 else
780 g_assert_not_reached ();
781
782 record_use (cfg, var2, u->bb, ins);
783
784 l = next;
785 }
786
787 info->uses = NULL;
788 }
789 }
790 }
791
792 if (cfg->verbose_level >= 4) {
793 MonoBasicBlock *bb;
794
795 for (bb = cfg->bb_entry; bb; bb = bb->next_bb)
796 mono_print_bb (bb, "AFTER SSA COPYPROP");
797 }
798 }
799
800 static int
801 evaluate_ins (MonoCompile *cfg, MonoInst *ins, MonoInst **res, MonoInst **carray)
802 {
803 MonoInst *args [MONO_MAX_SRC_REGS];
804 int rs [MONO_MAX_SRC_REGS];
805 MonoInst *c0;
806 gboolean const_args = TRUE;
807 const char *spec = INS_INFO (ins->opcode);
808 int num_sregs, i;
809 int sregs [MONO_MAX_SRC_REGS];
810
811 /* Short-circuit this */
812 if (ins->opcode == OP_ICONST) {
813 *res = ins;
814 return 1;
815 }
816
817 if (ins->opcode == OP_NOP)
818 return 2;
819
820 num_sregs = mono_inst_get_src_registers (ins, sregs);
821 for (i = 0; i < MONO_MAX_SRC_REGS; ++i)
822 args [i] = NULL;
823 for (i = 0; i < num_sregs; ++i) {
824 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
825
826 rs [i] = 2;
827 args [i] = carray [sregs [i]];
828 if (args [i])
829 rs [i] = 1;
830 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
831 rs [i] = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
832 if (rs [i] != 1)
833 const_args = FALSE;
834 }
835
836 c0 = NULL;
837
838 if (num_sregs > 0 && const_args) {
839 g_assert (num_sregs <= 2);
840 if ((spec [MONO_INST_DEST] != ' ') && carray [ins->dreg]) {
841 // Cached value
842 *res = carray [ins->dreg];
843 return 1;
844 }
845 c0 = mono_constant_fold_ins (cfg, ins, args [0], args [1], FALSE);
846 if (c0) {
847 if (G_UNLIKELY (cfg->verbose_level > 1)) {
848 printf ("\t cfold -> ");
849 mono_print_ins (c0);
850 }
851 *res = c0;
852 return 1;
853 }
854 else
855 /* Can't cfold this ins */
856 return 2;
857 }
858
859 if (num_sregs == 0)
860 return 2;
861 for (i = 0; i < num_sregs; ++i) {
862 if (rs [i] == 2)
863 return 2;
864 }
865 return 0;
866 }
867
868 static inline void
869 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
870 {
871 if (info->cpstate >= state)
872 return;
873
874 info->cpstate = state;
875
876 if (G_UNLIKELY (cfg->verbose_level > 1))
877 printf ("\tState of R%d set to %d\n", cfg->varinfo [info->idx]->dreg, info->cpstate);
878
879 if (state == 1)
880 g_assert (c0);
881
882 carray [cfg->varinfo [info->idx]->dreg] = c0;
883
884 if (!g_list_find (*cvars, info)) {
885 *cvars = g_list_prepend (*cvars, info);
886 }
887 }
888
889 static inline void
890 add_cprop_bb (MonoCompile *cfg, MonoBasicBlock *bb, GList **bblist)
891 {
892 if (G_UNLIKELY (cfg->verbose_level > 1))
893 printf ("\tAdd BB%d to worklist\n", bb->block_num);
894
895 if (!(bb->flags & BB_REACHABLE)) {
896 bb->flags |= BB_REACHABLE;
897 *bblist = g_list_prepend (*bblist, bb);
898 }
899 }
900
901 static void
902 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GList **cvars, GList **bblist, MonoInst **carray)
903 {
904 const char *spec = INS_INFO (ins->opcode);
905
906 if (ins->opcode == OP_NOP)
907 return;
908
909 if (cfg->verbose_level > 1)
910 mono_print_ins (ins);
911
912 /* FIXME: Support longs/floats */
913 /* FIXME: Work on vregs as well */
914
915 if (MONO_IS_PHI (ins)) {
916 MonoMethodVar *info = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, ins->dreg)->inst_c0);
917 MonoInst *c0 = NULL;
918 int j;
919
920 for (j = 1; j <= ins->inst_phi_args [0]; j++) {
921 MonoInst *var = get_vreg_to_inst (cfg, ins->inst_phi_args [j]);
922 MonoMethodVar *mv = MONO_VARINFO (cfg, var->inst_c0);
923 MonoInst *src = mv->def;
924
925 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE))
926 continue;
927
928 if (!mv->def || !src || mv->cpstate == 2) {
929 change_varstate (cfg, cvars, info, 2, NULL, carray);
930 break;
931 }
932
933 if (mv->cpstate == 0)
934 continue;
935
936 g_assert (carray [var->dreg]);
937
938 if (!c0)
939 c0 = carray [var->dreg];
940
941 /* FIXME: */
942 if (c0->opcode != OP_ICONST) {
943 change_varstate (cfg, cvars, info, 2, NULL, carray);
944 break;
945 }
946
947 if (carray [var->dreg]->inst_c0 != c0->inst_c0) {
948 change_varstate (cfg, cvars, info, 2, NULL, carray);
949 break;
950 }
951 }
952
953 if (c0 && info->cpstate < 1) {
954 change_varstate (cfg, cvars, info, 1, c0, carray);
955
956 g_assert (c0->opcode == OP_ICONST);
957 }
958 }
959 else if (!MONO_IS_STORE_MEMBASE (ins) && ((spec [MONO_INST_SRC1] != ' ') || (spec [MONO_INST_SRC2] != ' ') || (spec [MONO_INST_DEST] != ' '))) {
960 MonoInst *var, *c0;
961 int state;
962
963 if (spec [MONO_INST_DEST] != ' ')
964 var = get_vreg_to_inst (cfg, ins->dreg);
965 else
966 var = NULL;
967
968 c0 = NULL;
969 state = evaluate_ins (cfg, ins, &c0, carray);
970
971 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
972 MonoMethodVar *info = MONO_VARINFO (cfg, var->inst_c0);
973
974 if (info->cpstate < 2) {
975 if (state == 1)
976 change_varstate (cfg, cvars, info, 1, c0, carray);
977 else if (state == 2)
978 change_varstate (cfg, cvars, info, 2, NULL, carray);
979 }
980 }
981 else if (!var && (ins->dreg != -1)) {
982 /*
983 * We don't record def-use information for local vregs since it would be
984 * expensive. Instead, we depend on the fact that all uses of the vreg are in
985 * the same bblock, so they will be examined after the definition.
986 * FIXME: This isn't true if the ins is visited through an SSA edge.
987 */
988 if (c0) {
989 carray [ins->dreg] = c0;
990 } else {
991 if (carray [ins->dreg]) {
992 /*
993 * The state of the vreg changed from constant to non-constant
994 * -> need to rescan the whole bblock.
995 */
996 carray [ins->dreg] = NULL;
997 /* FIXME: Speed this up */
998
999 if (!g_list_find (*bblist, bb))
1000 *bblist = g_list_prepend (*bblist, bb);
1001 }
1002 }
1003 }
1004
1005 if (MONO_IS_JUMP_TABLE (ins)) {
1006 int i;
1007 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1008
1009 if (!ins->next || ins->next->opcode != OP_PADD) {
1010 /* The PADD was optimized away */
1011 /* FIXME: handle this as well */
1012 for (i = 0; i < table->table_size; i++)
1013 if (table->table [i])
1014 add_cprop_bb (cfg, table->table [i], bblist);
1015 return;
1016 }
1017
1018 g_assert (ins->next->opcode == OP_PADD);
1019 g_assert (ins->next->sreg1 == ins->dreg);
1020
1021 if (carray [ins->next->sreg2]) {
1022 #if SIZEOF_REGISTER == 8
1023 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1024 #else
1025 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1026 #endif
1027 if ((idx < 0) || (idx >= table->table_size))
1028 /* Out-of-range, no branch is executed */
1029 return;
1030 else
1031 if (table->table [idx])
1032 add_cprop_bb (cfg, table->table [idx], bblist);
1033 }
1034 else {
1035 for (i = 0; i < table->table_size; i++)
1036 if (table->table [i])
1037 add_cprop_bb (cfg, table->table [i], bblist);
1038 }
1039 }
1040
1041 if (ins->opcode == OP_SWITCH) {
1042 int i;
1043 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)ins->inst_p0;
1044
1045 for (i = 0; i < table->table_size; i++)
1046 if (table->table [i])
1047 add_cprop_bb (cfg, table->table [i], bblist);
1048 }
1049
1050 /* Handle COMPARE+BRCOND pairs */
1051 if (ins->next && MONO_IS_COND_BRANCH_OP (ins->next)) {
1052 if (c0) {
1053 g_assert (c0->opcode == OP_ICONST);
1054
1055 if (c0->inst_c0)
1056 ins->next->flags |= MONO_INST_CFOLD_TAKEN;
1057 else
1058 ins->next->flags |= MONO_INST_CFOLD_NOT_TAKEN;
1059 }
1060 else {
1061 ins->next->flags &= ~(MONO_INST_CFOLD_TAKEN | MONO_INST_CFOLD_NOT_TAKEN);
1062 }
1063
1064 visit_inst (cfg, bb, ins->next, cvars, bblist, carray);
1065 }
1066 } else if (ins->opcode == OP_BR) {
1067 add_cprop_bb (cfg, ins->inst_target_bb, bblist);
1068 } else if (MONO_IS_COND_BRANCH_OP (ins)) {
1069 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1070 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1071 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1072 if (ins->inst_false_bb)
1073 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1074 } else {
1075 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1076 if (ins->inst_false_bb)
1077 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1078 }
1079 }
1080 }
1081
1082 /**
1083 * fold_ins:
1084 *
1085 * Replace INS with its constant value, if it exists
1086 */
1087 static void
1088 fold_ins (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, MonoInst **carray)
1089 {
1090 const char *spec = INS_INFO (ins->opcode);
1091 int opcode2;
1092 int num_sregs = mono_inst_get_num_src_registers (ins);
1093
1094 if ((ins->opcode != OP_NOP) && (ins->dreg != -1) && !MONO_IS_STORE_MEMBASE (ins)) {
1095 if (carray [ins->dreg] && (spec [MONO_INST_DEST] == 'i') && (ins->dreg >= MONO_MAX_IREGS)) {
1096 /* Perform constant folding */
1097 /* FIXME: */
1098 g_assert (carray [ins->dreg]->opcode == OP_ICONST);
1099 ins->opcode = OP_ICONST;
1100 ins->inst_c0 = carray [ins->dreg]->inst_c0;
1101 MONO_INST_NULLIFY_SREGS (ins);
1102 } else if (num_sregs == 2 && carray [ins->sreg2]) {
1103 /* Perform op->op_imm conversion */
1104 opcode2 = mono_op_to_op_imm (ins->opcode);
1105 if (opcode2 != -1) {
1106 ins->opcode = opcode2;
1107 ins->inst_imm = carray [ins->sreg2]->inst_c0;
1108 ins->sreg2 = -1;
1109
1110 if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
1111 ((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
1112 }
1113 } else {
1114 /* FIXME: Handle 3 op insns */
1115 }
1116
1117 if (MONO_IS_JUMP_TABLE (ins)) {
1118 int i;
1119 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1120
1121 if (!ins->next || ins->next->opcode != OP_PADD) {
1122 /* The PADD was optimized away */
1123 /* FIXME: handle this as well */
1124 return;
1125 }
1126
1127 g_assert (ins->next->opcode == OP_PADD);
1128 g_assert (ins->next->sreg1 == ins->dreg);
1129 g_assert (ins->next->next->opcode == OP_LOAD_MEMBASE);
1130
1131 if (carray [ins->next->sreg2]) {
1132 /* Convert to a simple branch */
1133 #if SIZEOF_REGISTER == 8
1134 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1135 #else
1136 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1137 #endif
1138
1139 if (!((idx >= 0) && (idx < table->table_size))) {
1140 /* Out of range, eliminate the whole switch */
1141 for (i = 0; i < table->table_size; ++i) {
1142 remove_bb_from_phis (cfg, bb, table->table [i]);
1143 mono_unlink_bblock (cfg, bb, table->table [i]);
1144 }
1145
1146 NULLIFY_INS (ins);
1147 NULLIFY_INS (ins->next);
1148 NULLIFY_INS (ins->next->next);
1149 if (ins->next->next->next)
1150 NULLIFY_INS (ins->next->next->next);
1151
1152 return;
1153 }
1154
1155 if (!ins->next->next->next || ins->next->next->next->opcode != OP_BR_REG) {
1156 /* A one-way switch which got optimized away */
1157 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1158 printf ("\tNo cfold on ");
1159 mono_print_ins (ins);
1160 }
1161 return;
1162 }
1163
1164 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1165 printf ("\tcfold on ");
1166 mono_print_ins (ins);
1167 }
1168
1169 /* Unlink target bblocks */
1170 for (i = 0; i < table->table_size; ++i) {
1171 if (table->table [i] != table->table [idx]) {
1172 remove_bb_from_phis (cfg, bb, table->table [i]);
1173 mono_unlink_bblock (cfg, bb, table->table [i]);
1174 }
1175 }
1176
1177 /* Change the OP_BR_REG to a simple branch */
1178 ins->next->next->next->opcode = OP_BR;
1179 ins->next->next->next->inst_target_bb = table->table [idx];
1180 ins->next->next->next->sreg1 = -1;
1181
1182 /* Nullify the other instructions */
1183 NULLIFY_INS (ins);
1184 NULLIFY_INS (ins->next);
1185 NULLIFY_INS (ins->next->next);
1186 }
1187 }
1188 }
1189 else if (MONO_IS_COND_BRANCH_OP (ins)) {
1190 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1191 remove_bb_from_phis (cfg, bb, ins->inst_false_bb);
1192 mono_unlink_bblock (cfg, bb, ins->inst_false_bb);
1193 ins->opcode = OP_BR;
1194 ins->inst_target_bb = ins->inst_true_bb;
1195 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1196 remove_bb_from_phis (cfg, bb, ins->inst_true_bb);
1197 mono_unlink_bblock (cfg, bb, ins->inst_true_bb);
1198 ins->opcode = OP_BR;
1199 ins->inst_target_bb = ins->inst_false_bb;
1200 }
1201 }
1202 }
1203
1204 void
1205 mono_ssa_cprop (MonoCompile *cfg)
1206 {
1207 MonoInst **carray;
1208 MonoBasicBlock *bb;
1209 GList *bblock_list, *cvars;
1210 GList *tmp;
1211 int i;
1212 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1213
1214 carray = g_new0 (MonoInst*, cfg->next_vreg);
1215
1216 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1217 mono_ssa_create_def_use (cfg);
1218
1219 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1220 cfg->bb_entry->flags |= BB_REACHABLE;
1221
1222 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1223
1224 for (i = 0; i < cfg->num_varinfo; i++) {
1225 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1226 if (!info->def)
1227 info->cpstate = 2;
1228 }
1229
1230 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1231 /*
1232 * FIXME: This should be bb->flags & BB_FLAG_EXCEPTION_HANDLER, but
1233 * that would still allow unreachable try's to be removed.
1234 */
1235 if (bb->region)
1236 add_cprop_bb (cfg, bb, &bblock_list);
1237 }
1238
1239 cvars = NULL;
1240
1241 while (bblock_list) {
1242 MonoInst *inst;
1243
1244 bb = (MonoBasicBlock *)bblock_list->data;
1245
1246 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1247
1248 g_assert (bb->flags & BB_REACHABLE);
1249
1250 /*
1251 * Some bblocks are linked to 2 others even through they fall through to the
1252 * next bblock.
1253 */
1254 if (!(bb->last_ins && MONO_IS_BRANCH_OP (bb->last_ins))) {
1255 for (i = 0; i < bb->out_count; ++i)
1256 add_cprop_bb (cfg, bb->out_bb [i], &bblock_list);
1257 }
1258
1259 if (cfg->verbose_level > 1)
1260 printf ("\nSSA CONSPROP BB%d:\n", bb->block_num);
1261
1262 for (inst = bb->code; inst; inst = inst->next) {
1263 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1264 }
1265
1266 while (cvars) {
1267 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1268 cvars = g_list_delete_link (cvars, cvars);
1269
1270 for (tmp = info->uses; tmp; tmp = tmp->next) {
1271 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1272 if (!(ui->bb->flags & BB_REACHABLE))
1273 continue;
1274 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1275 }
1276 }
1277 }
1278
1279 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1280 MonoInst *inst;
1281 for (inst = bb->code; inst; inst = inst->next) {
1282 fold_ins (cfg, bb, inst, carray);
1283 }
1284 }
1285
1286 g_free (carray);
1287
1288 cfg->comp_done |= MONO_COMP_REACHABILITY;
1289
1290 /* fixme: we should update usage infos during cprop, instead of computing it again */
1291 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1292 for (i = 0; i < cfg->num_varinfo; i++) {
1293 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1294 info->def = NULL;
1295 info->uses = NULL;
1296 }
1297 }
1298
1299 static inline void
1300 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1301 {
1302 GList *tmp;
1303
1304 *wl = g_list_prepend_mempool (cfg->mempool, *wl, use);
1305
1306 for (tmp = use->uses; tmp; tmp = tmp->next) {
1307 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1308 if (ui->inst == var->def) {
1309 /* from the mempool */
1310 use->uses = g_list_remove_link (use->uses, tmp);
1311 break;
1312 }
1313 }
1314 }
1315
1316 void
1317 mono_ssa_deadce (MonoCompile *cfg)
1318 {
1319 int i;
1320 GList *work_list;
1321
1322 g_assert (cfg->comp_done & MONO_COMP_SSA);
1323
1324 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1325
1326 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1327 mono_ssa_create_def_use (cfg);
1328
1329 mono_ssa_copyprop (cfg);
1330
1331 work_list = NULL;
1332 for (i = 0; i < cfg->num_varinfo; i++) {
1333 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1334 work_list = g_list_prepend_mempool (cfg->mempool, work_list, info);
1335 }
1336
1337 while (work_list) {
1338 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1339 work_list = g_list_remove_link (work_list, work_list);
1340
1341 /*
1342 * The second part of the condition happens often when PHI nodes have their dreg
1343 * as one of their arguments due to the fact that we use the original vars.
1344 */
1345 if (info->def && (!info->uses || ((info->uses->next == NULL) && (((MonoVarUsageInfo*)info->uses->data)->inst == info->def)))) {
1346 MonoInst *def = info->def;
1347
1348 /* Eliminating FMOVE could screw up the fp stack */
1349 if (MONO_IS_MOVE (def) && (!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE))) {
1350 MonoInst *src_var = get_vreg_to_inst (cfg, def->sreg1);
1351 if (src_var && !(src_var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1352 add_to_dce_worklist (cfg, info, MONO_VARINFO (cfg, src_var->inst_c0), &work_list);
1353 NULLIFY_INS (def);
1354 info->reg = -1;
1355 } else if ((def->opcode == OP_ICONST) || (def->opcode == OP_I8CONST) || MONO_IS_ZERO (def)) {
1356 NULLIFY_INS (def);
1357 info->reg = -1;
1358 } else if (MONO_IS_PHI (def)) {
1359 int j;
1360 for (j = def->inst_phi_args [0]; j > 0; j--) {
1361 MonoMethodVar *u = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, def->inst_phi_args [j])->inst_c0);
1362 add_to_dce_worklist (cfg, info, u, &work_list);
1363 }
1364 NULLIFY_INS (def);
1365 info->reg = -1;
1366 }
1367 else if (def->opcode == OP_NOP) {
1368 }
1369 //else
1370 //mono_print_ins (def);
1371 }
1372
1373 }
1374 }
1375
1376 #if 0
1377 void
1378 mono_ssa_strength_reduction (MonoCompile *cfg)
1379 {
1380 MonoBasicBlock *bb;
1381 int i;
1382
1383 g_assert (cfg->comp_done & MONO_COMP_SSA);
1384 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1385 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1386
1387 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1388 GList *lp = bb->loop_blocks;
1389
1390 if (lp) {
1391 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1392
1393 /* we only consider loops with 2 in bblocks */
1394 if (!h->in_count == 2)
1395 continue;
1396
1397 for (i = 0; i < cfg->num_varinfo; i++) {
1398 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1399
1400 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1401 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1402 MonoInst *v = info->def->inst_i1;
1403
1404
1405 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1406 }
1407 }
1408 }
1409 }
1410 }
1411 #endif
1412
1413 void
1414 mono_ssa_loop_invariant_code_motion (MonoCompile *cfg)
1415 {
1416 MonoBasicBlock *bb, *h, *idom;
1417 MonoInst *ins, *n, *tins;
1418 int i;
1419
1420 g_assert (cfg->comp_done & MONO_COMP_SSA);
1421 if (!(cfg->comp_done & MONO_COMP_LOOPS) || !(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1422 return;
1423
1424 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1425 GList *lp = bb->loop_blocks;
1426
1427 if (!lp)
1428 continue;
1429 h = (MonoBasicBlock *)lp->data;
1430 if (bb != h)
1431 continue;
1432 MONO_BB_FOR_EACH_INS_SAFE (bb, n, ins) {
1433 /*
1434 * Try to move instructions out of loop headers into the preceeding bblock.
1435 */
1436 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS || ins->opcode == OP_AOTCONST || ins->opcode == OP_GENERIC_CLASS_INIT) {
1437 gboolean skip;
1438 int sreg;
1439
1440 idom = h->idom;
1441 /*
1442 * h->nesting is needed to work around:
1443 * http://llvm.org/bugs/show_bug.cgi?id=17868
1444 */
1445 if (!(idom && idom->last_ins && idom->last_ins->opcode == OP_BR && idom->last_ins->inst_target_bb == h && h->nesting == 1)) {
1446 continue;
1447 }
1448
1449 /*
1450 * Make sure there are no instructions with side effects before ins.
1451 */
1452 skip = FALSE;
1453 MONO_BB_FOR_EACH_INS (bb, tins) {
1454 if (tins == ins)
1455 break;
1456 if (!MONO_INS_HAS_NO_SIDE_EFFECT (tins)) {
1457 skip = TRUE;
1458 break;
1459 }
1460 }
1461 if (skip) {
1462 /*
1463 printf ("%s\n", mono_method_full_name (cfg->method, TRUE));
1464 mono_print_ins (tins);
1465 */
1466 continue;
1467 }
1468
1469 /* Make sure we don't move the instruction before the def of its sreg */
1470 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS)
1471 sreg = ins->sreg1;
1472 else
1473 sreg = -1;
1474 if (sreg != -1) {
1475 MonoInst *tins, *var;
1476
1477 skip = FALSE;
1478 for (tins = ins->prev; tins; tins = tins->prev) {
1479 const char *spec = INS_INFO (tins->opcode);
1480
1481 if (tins->opcode == OP_MOVE && tins->dreg == sreg) {
1482 sreg = tins->sreg1;
1483 } if (spec [MONO_INST_DEST] != ' ' && tins->dreg == sreg) {
1484 skip = TRUE;
1485 break;
1486 }
1487 }
1488 if (skip)
1489 continue;
1490 var = get_vreg_to_inst (cfg, sreg);
1491 if (var && (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1492 continue;
1493 ins->sreg1 = sreg;
1494 }
1495
1496 if (cfg->verbose_level > 1) {
1497 printf ("licm in BB%d on ", bb->block_num);
1498 mono_print_ins (ins);
1499 }
1500 //{ static int count = 0; count ++; printf ("%d\n", count); }
1501 MONO_REMOVE_INS (bb, ins);
1502 mono_bblock_insert_before_ins (idom, idom->last_ins, ins);
1503 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN)
1504 idom->has_array_access = TRUE;
1505 }
1506 }
1507 }
1508
1509 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1510 for (i = 0; i < cfg->num_varinfo; i++) {
1511 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1512 info->def = NULL;
1513 info->uses = NULL;
1514 }
1515 }
1516
1517 #endif /* DISABLE_JIT */
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