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Merge pull request #3140 from esdrubal/syscall_details
[mono-project.git] / mono / mini / ssa.c
blobcb100267ef706a6c3608f7b09e12f5dcb92e1cfb
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 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
10 */
11 #include <config.h>
12 #include <string.h>
13 #include <mono/metadata/debug-helpers.h>
14 #include <mono/metadata/mempool.h>
15 #include <mono/metadata/mempool-internals.h>
16
17 #ifndef DISABLE_JIT
18
19 #include "mini.h"
20 #ifdef HAVE_ALLOCA_H
21 #include <alloca.h>
22 #endif
23
24 #define CREATE_PRUNED_SSA
25
26 //#define DEBUG_SSA 1
27
28 #define NEW_PHI(cfg,dest,val) do { \
29 MONO_INST_NEW ((cfg), (dest), OP_PHI); \
30 (dest)->inst_c0 = (val); \
31 } while (0)
32
33 typedef struct {
34 MonoBasicBlock *bb;
35 MonoInst *inst;
36 } MonoVarUsageInfo;
37
38 static void
39 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
40 {
41 int i;
42
43 for (i = 0; i < bb->out_count; i++) {
44 if (bb->out_bb [i] == target) {
45 bb->out_bb [i] = bb->out_bb [--bb->out_count];
46 break;
47 }
48 }
49 for (i = 0; i < target->in_count; i++) {
50 if (target->in_bb [i] == bb) {
51 target->in_bb [i] = target->in_bb [--target->in_count];
52 break;
53
54 }
55 }
56 }
57
58 static void
59 unlink_unused_bblocks (MonoCompile *cfg)
60 {
61 int i, j;
62 MonoBasicBlock *bb;
63
64 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
65
66 if (G_UNLIKELY (cfg->verbose_level > 1))
67 printf ("\nUNLINK UNUSED BBLOCKS:\n");
68
69 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
70 if (!(bb->next_bb->flags & BB_REACHABLE)) {
71 bb->next_bb = bb->next_bb->next_bb;
72 } else
73 bb = bb->next_bb;
74 }
75
76 for (i = 1; i < cfg->num_bblocks; i++) {
77 bb = cfg->bblocks [i];
78
79 if (!(bb->flags & BB_REACHABLE)) {
80 for (j = 0; j < bb->in_count; j++) {
81 unlink_target (bb->in_bb [j], bb);
82 }
83 for (j = 0; j < bb->out_count; j++) {
84 unlink_target (bb, bb->out_bb [j]);
85 }
86 if (G_UNLIKELY (cfg->verbose_level > 1))
87 printf ("\tUnlinked BB%d\n", bb->block_num);
88 }
89
90 }
91 }
92
93 /**
94 * remove_bb_from_phis:
95 *
96 * Remove BB from the PHI statements in TARGET.
97 */
98 static void
99 remove_bb_from_phis (MonoCompile *cfg, MonoBasicBlock *bb, MonoBasicBlock *target)
100 {
101 MonoInst *ins;
102 int i, j;
103
104 for (i = 0; i < target->in_count; i++) {
105 if (target->in_bb [i] == bb) {
106 break;
107 }
108 }
109 g_assert (i < target->in_count);
110
111 for (ins = target->code; ins; ins = ins->next) {
112 if (MONO_IS_PHI (ins)) {
113 for (j = i; j < ins->inst_phi_args [0] - 1; ++j)
114 ins->inst_phi_args [j + 1] = ins->inst_phi_args [j + 2];
115 ins->inst_phi_args [0] --;
116 }
117 else
118 break;
119 }
120 }
121
122 static inline int
123 op_phi_to_move (int opcode)
124 {
125 switch (opcode) {
126 case OP_PHI:
127 return OP_MOVE;
128 case OP_FPHI:
129 return OP_FMOVE;
130 case OP_VPHI:
131 return OP_VMOVE;
132 case OP_XPHI:
133 return OP_XMOVE;
134 default:
135 g_assert_not_reached ();
136 }
137
138 return -1;
139 }
140
141 static inline void
142 record_use (MonoCompile *cfg, MonoInst *var, MonoBasicBlock *bb, MonoInst *ins)
143 {
144 MonoMethodVar *info;
145 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
146
147 info = MONO_VARINFO (cfg, var->inst_c0);
148
149 ui->bb = bb;
150 ui->inst = ins;
151 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
152 }
153
154 typedef struct {
155 MonoInst *var;
156 int idx;
157 } RenameInfo;
158
159 /**
160 * mono_ssa_rename_vars:
161 *
162 * Implement renaming of SSA variables. Also compute def-use information in parallel.
163 * @stack_history points to an area of memory which can be used for storing changes
164 * made to the stack, so they can be reverted later.
165 */
166 static void
167 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)
168 {
169 MonoInst *ins, *new_var;
170 int i, j, idx;
171 GSList *tmp;
172 int stack_history_len = 0;
173
174 if (cfg->verbose_level >= 4)
175 printf ("\nRENAME VARS BLOCK %d:\n", bb->block_num);
176
177 /* First pass: Create new vars */
178 for (ins = bb->code; ins; ins = ins->next) {
179 const char *spec = INS_INFO (ins->opcode);
180 int num_sregs;
181 int sregs [MONO_MAX_SRC_REGS];
182
183 #ifdef DEBUG_SSA
184 printf ("\tProcessing "); mono_print_ins (ins);
185 #endif
186 if (ins->opcode == OP_NOP)
187 continue;
188
189 /* SREGs */
190 num_sregs = mono_inst_get_src_registers (ins, sregs);
191 for (i = 0; i < num_sregs; ++i) {
192 if (spec [MONO_INST_SRC1 + i] != ' ') {
193 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
194 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
195 int idx = var->inst_c0;
196 if (stack [idx]) {
197 if (var->opcode != OP_ARG)
198 g_assert (stack [idx]);
199 sregs [i] = stack [idx]->dreg;
200 record_use (cfg, stack [idx], bb, ins);
201 }
202 else
203 record_use (cfg, var, bb, ins);
204 }
205 else if (G_UNLIKELY (!var && lvreg_stack [sregs [i]]))
206 sregs [i] = lvreg_stack [sregs [i]];
207 }
208 }
209 mono_inst_set_src_registers (ins, sregs);
210
211 if (MONO_IS_STORE_MEMBASE (ins)) {
212 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
213 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
214 int idx = var->inst_c0;
215 if (stack [idx]) {
216 if (var->opcode != OP_ARG)
217 g_assert (stack [idx]);
218 ins->dreg = stack [idx]->dreg;
219 record_use (cfg, stack [idx], bb, ins);
220 }
221 else
222 record_use (cfg, var, bb, ins);
223 }
224 else if (G_UNLIKELY (!var && lvreg_stack [ins->dreg]))
225 ins->dreg = lvreg_stack [ins->dreg];
226 }
227
228 /* DREG */
229 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
230 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
231 MonoMethodVar *info;
232
233 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
234 idx = var->inst_c0;
235 g_assert (idx < max_vars);
236
237 if (var->opcode == OP_ARG)
238 originals_used [idx] = TRUE;
239
240 /* FIXME: */
241 g_assert (stack_history_len < stack_history_size);
242 stack_history [stack_history_len].var = stack [idx];
243 stack_history [stack_history_len].idx = idx;
244 stack_history_len ++;
245
246 if (originals_used [idx]) {
247 new_var = mono_compile_create_var (cfg, var->inst_vtype, OP_LOCAL);
248 new_var->flags = var->flags;
249 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
250
251 if (cfg->verbose_level >= 4)
252 printf (" R%d -> R%d\n", var->dreg, new_var->dreg);
253
254 stack [idx] = new_var;
255
256 ins->dreg = new_var->dreg;
257 var = new_var;
258 }
259 else {
260 stack [idx] = var;
261 originals_used [idx] = TRUE;
262 }
263
264 info = MONO_VARINFO (cfg, var->inst_c0);
265 info->def = ins;
266 info->def_bb = bb;
267 }
268 else if (G_UNLIKELY (!var && lvreg_defined [ins->dreg] && (ins->dreg >= MONO_MAX_IREGS))) {
269 /* Perform renaming for local vregs */
270 lvreg_stack [ins->dreg] = vreg_is_ref (cfg, ins->dreg) ? mono_alloc_ireg_ref (cfg) : mono_alloc_preg (cfg);
271 ins->dreg = lvreg_stack [ins->dreg];
272 }
273 else
274 lvreg_defined [ins->dreg] = TRUE;
275 }
276
277 #ifdef DEBUG_SSA
278 printf ("\tAfter processing "); mono_print_ins (ins);
279 #endif
280
281 }
282
283 /* Rename PHI arguments in succeeding bblocks */
284 for (i = 0; i < bb->out_count; i++) {
285 MonoBasicBlock *n = bb->out_bb [i];
286
287 for (j = 0; j < n->in_count; j++)
288 if (n->in_bb [j] == bb)
289 break;
290
291 for (ins = n->code; ins; ins = ins->next) {
292 if (MONO_IS_PHI (ins)) {
293 idx = ins->inst_c0;
294 if (stack [idx])
295 new_var = stack [idx];
296 else
297 new_var = cfg->varinfo [idx];
298 #ifdef DEBUG_SSA
299 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
300 #endif
301 ins->inst_phi_args [j + 1] = new_var->dreg;
302 record_use (cfg, new_var, n, ins);
303 if (G_UNLIKELY (cfg->verbose_level >= 4))
304 printf ("\tAdd PHI R%d <- R%d to BB%d\n", ins->dreg, new_var->dreg, n->block_num);
305 }
306 else
307 /* The phi nodes are at the beginning of the bblock */
308 break;
309 }
310 }
311
312 if (bb->dominated) {
313 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
314 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);
315 }
316 }
317
318 /* Restore stack */
319 for (i = stack_history_len - 1; i >= 0; i--) {
320 stack [stack_history [i].idx] = stack_history [i].var;
321 }
322
323 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
324 }
325
326 void
327 mono_ssa_compute (MonoCompile *cfg)
328 {
329 int i, j, idx, bitsize;
330 MonoBitSet *set;
331 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
332 MonoInst *ins, **stack;
333 guint8 *buf, *buf_start;
334 RenameInfo *stack_history;
335 int stack_history_size;
336 gboolean *originals;
337 guint32 *lvreg_stack;
338 gboolean *lvreg_defined;
339
340 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
341
342 g_assert (!cfg->disable_ssa);
343
344 if (cfg->verbose_level >= 4)
345 printf ("\nCOMPUTE SSA %d (R%d-)\n\n", cfg->num_varinfo, cfg->next_vreg);
346
347 #ifdef CREATE_PRUNED_SSA
348 /* we need liveness for pruned SSA */
349 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
350 mono_analyze_liveness (cfg);
351 #endif
352
353 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
354
355 bitsize = mono_bitset_alloc_size (cfg->num_bblocks, 0);
356 buf = buf_start = (guint8 *)g_malloc0 (mono_bitset_alloc_size (cfg->num_bblocks, 0) * cfg->num_varinfo);
357
358 for (i = 0; i < cfg->num_varinfo; ++i) {
359 vinfo [i].def_in = mono_bitset_mem_new (buf, cfg->num_bblocks, 0);
360 buf += bitsize;
361 vinfo [i].idx = i;
362 /* implicit reference at start */
363 if (cfg->varinfo [i]->opcode == OP_ARG)
364 mono_bitset_set_fast (vinfo [i].def_in, 0);
365 }
366
367 for (i = 0; i < cfg->num_bblocks; ++i) {
368 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], ins) {
369 if (ins->opcode == OP_NOP)
370 continue;
371
372 if (!MONO_IS_STORE_MEMBASE (ins) && get_vreg_to_inst (cfg, ins->dreg)) {
373 mono_bitset_set_fast (vinfo [get_vreg_to_inst (cfg, ins->dreg)->inst_c0].def_in, i);
374 }
375 }
376 }
377
378 /* insert phi functions */
379 for (i = 0; i < cfg->num_varinfo; ++i) {
380 MonoInst *var = cfg->varinfo [i];
381
382 #if SIZEOF_REGISTER == 4
383 if (var->type == STACK_I8 && !COMPILE_LLVM (cfg))
384 continue;
385 #endif
386 if (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))
387 continue;
388
389 /* Most variables have only one definition */
390 if (mono_bitset_count (vinfo [i].def_in) <= 1)
391 continue;
392
393 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
394
395 if (cfg->verbose_level >= 4) {
396 if (mono_bitset_count (set) > 0) {
397 printf ("\tR%d needs PHI functions in ", var->dreg);
398 mono_blockset_print (cfg, set, "", -1);
399 }
400 }
401
402 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
403 MonoBasicBlock *bb = cfg->bblocks [idx];
404
405 /* fixme: create pruned SSA? we would need liveness information for that */
406
407 if (bb == cfg->bb_exit && !COMPILE_LLVM (cfg))
408 continue;
409
410 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
411 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
412 continue;
413 }
414
415 NEW_PHI (cfg, ins, i);
416
417 switch (var->type) {
418 case STACK_I4:
419 case STACK_I8:
420 case STACK_PTR:
421 case STACK_MP:
422 case STACK_OBJ:
423 ins->opcode = OP_PHI;
424 break;
425 case STACK_R8:
426 ins->opcode = OP_FPHI;
427 break;
428 case STACK_VTYPE:
429 ins->opcode = MONO_CLASS_IS_SIMD (cfg, var->klass) ? OP_XPHI : OP_VPHI;
430 break;
431 }
432
433 if (var->inst_vtype->byref)
434 ins->klass = mono_defaults.int_class;
435 else
436 ins->klass = var->klass;
437
438 ins->inst_phi_args = (int *)mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
439 ins->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
440
441 /* For debugging */
442 for (j = 0; j < cfg->bblocks [idx]->in_count; ++j)
443 ins->inst_phi_args [j + 1] = -1;
444
445 ins->dreg = cfg->varinfo [i]->dreg;
446
447 mono_bblock_insert_before_ins (bb, bb->code, ins);
448
449 #ifdef DEBUG_SSA
450 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
451 #endif
452 }
453 }
454
455 /* free the stuff */
456 g_free (vinfo);
457 g_free (buf_start);
458
459 /* Renaming phase */
460
461 stack = (MonoInst **)alloca (sizeof (MonoInst *) * cfg->num_varinfo);
462 memset (stack, 0, sizeof (MonoInst *) * cfg->num_varinfo);
463
464 lvreg_stack = g_new0 (guint32, cfg->next_vreg);
465 lvreg_defined = g_new0 (gboolean, cfg->next_vreg);
466 stack_history_size = 10240;
467 stack_history = g_new (RenameInfo, stack_history_size);
468 originals = g_new0 (gboolean, cfg->num_varinfo);
469 mono_ssa_rename_vars (cfg, cfg->num_varinfo, cfg->bb_entry, originals, stack, lvreg_stack, lvreg_defined, stack_history, stack_history_size);
470 g_free (stack_history);
471 g_free (originals);
472 g_free (lvreg_stack);
473 g_free (lvreg_defined);
474
475 if (cfg->verbose_level >= 4)
476 printf ("\nEND COMPUTE SSA.\n\n");
477
478 cfg->comp_done |= MONO_COMP_SSA;
479 }
480
481 /*
482 * mono_ssa_remove_gsharedvt:
483 *
484 * Same as mono_ssa_remove, but only remove phi nodes for gsharedvt variables.
485 */
486 void
487 mono_ssa_remove_gsharedvt (MonoCompile *cfg)
488 {
489 MonoInst *ins, *var, *move;
490 int i, j, first;
491
492 /*
493 * When compiling gsharedvt code, we need to get rid of the VPHI instructions,
494 * since they cannot be handled later in the llvm backend.
495 */
496 g_assert (cfg->comp_done & MONO_COMP_SSA);
497
498 for (i = 0; i < cfg->num_bblocks; ++i) {
499 MonoBasicBlock *bb = cfg->bblocks [i];
500
501 if (cfg->verbose_level >= 4)
502 printf ("\nREMOVE SSA %d:\n", bb->block_num);
503
504 for (ins = bb->code; ins; ins = ins->next) {
505 if (!(MONO_IS_PHI (ins) && ins->opcode == OP_VPHI && mini_is_gsharedvt_variable_type (&ins->klass->byval_arg)))
506 continue;
507
508 g_assert (ins->inst_phi_args [0] == bb->in_count);
509 var = get_vreg_to_inst (cfg, ins->dreg);
510
511 /* Check for PHI nodes where all the inputs are the same */
512 first = ins->inst_phi_args [1];
513
514 for (j = 1; j < bb->in_count; ++j)
515 if (first != ins->inst_phi_args [j + 1])
516 break;
517
518 if ((bb->in_count > 1) && (j == bb->in_count)) {
519 ins->opcode = op_phi_to_move (ins->opcode);
520 if (ins->opcode == OP_VMOVE)
521 g_assert (ins->klass);
522 ins->sreg1 = first;
523 } else {
524 for (j = 0; j < bb->in_count; j++) {
525 MonoBasicBlock *pred = bb->in_bb [j];
526 int sreg = ins->inst_phi_args [j + 1];
527
528 if (cfg->verbose_level >= 4)
529 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
530 if (var->dreg != sreg) {
531 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
532 if (move->opcode == OP_VMOVE) {
533 g_assert (ins->klass);
534 move->klass = ins->klass;
535 }
536 move->dreg = var->dreg;
537 move->sreg1 = sreg;
538 mono_add_ins_to_end (pred, move);
539 }
540 }
541
542 NULLIFY_INS (ins);
543 }
544 }
545 }
546 }
547
548 void
549 mono_ssa_remove (MonoCompile *cfg)
550 {
551 MonoInst *ins, *var, *move;
552 int bbindex, i, j, first;
553
554 g_assert (cfg->comp_done & MONO_COMP_SSA);
555
556 for (i = 0; i < cfg->num_bblocks; ++i) {
557 MonoBasicBlock *bb = cfg->bblocks [i];
558
559 if (cfg->verbose_level >= 4)
560 printf ("\nREMOVE SSA %d:\n", bb->block_num);
561
562 for (ins = bb->code; ins; ins = ins->next) {
563 if (MONO_IS_PHI (ins)) {
564 g_assert (ins->inst_phi_args [0] == bb->in_count);
565 var = get_vreg_to_inst (cfg, ins->dreg);
566
567 /* Check for PHI nodes where all the inputs are the same */
568 first = ins->inst_phi_args [1];
569
570 for (j = 1; j < bb->in_count; ++j)
571 if (first != ins->inst_phi_args [j + 1])
572 break;
573
574 if ((bb->in_count > 1) && (j == bb->in_count)) {
575 ins->opcode = op_phi_to_move (ins->opcode);
576 if (ins->opcode == OP_VMOVE)
577 g_assert (ins->klass);
578 ins->sreg1 = first;
579 } else {
580 for (j = 0; j < bb->in_count; j++) {
581 MonoBasicBlock *pred = bb->in_bb [j];
582 int sreg = ins->inst_phi_args [j + 1];
583
584 if (cfg->verbose_level >= 4)
585 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
586 if (var->dreg != sreg) {
587 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
588 if (move->opcode == OP_VMOVE) {
589 g_assert (ins->klass);
590 move->klass = ins->klass;
591 }
592 move->dreg = var->dreg;
593 move->sreg1 = sreg;
594 mono_add_ins_to_end (pred, move);
595 }
596 }
597
598 NULLIFY_INS (ins);
599 }
600 }
601 }
602 }
603
604 if (cfg->verbose_level >= 4) {
605 for (i = 0; i < cfg->num_bblocks; ++i) {
606 MonoBasicBlock *bb = cfg->bblocks [i];
607
608 mono_print_bb (bb, "AFTER REMOVE SSA:");
609 }
610 }
611
612 /*
613 * Removal of SSA form introduces many copies. To avoid this, we tyry to coalesce
614 * the variables if possible. Since the newly introduced SSA variables don't
615 * have overlapping live ranges (because we don't do agressive optimization), we
616 * can coalesce them into the original variable.
617 */
618
619 for (bbindex = 0; bbindex < cfg->num_bblocks; ++bbindex) {
620 MonoBasicBlock *bb = cfg->bblocks [bbindex];
621
622 for (ins = bb->code; ins; ins = ins->next) {
623 const char *spec = INS_INFO (ins->opcode);
624 int num_sregs;
625 int sregs [MONO_MAX_SRC_REGS];
626
627 if (ins->opcode == OP_NOP)
628 continue;
629
630 if (spec [MONO_INST_DEST] != ' ') {
631 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
632
633 if (var) {
634 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
635
636 /*
637 * The third condition avoids coalescing with variables eliminated
638 * during deadce.
639 */
640 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
641 printf ("COALESCE: R%d -> R%d\n", ins->dreg, cfg->varinfo [vmv->reg]->dreg);
642 ins->dreg = cfg->varinfo [vmv->reg]->dreg;
643 }
644 }
645 }
646
647 num_sregs = mono_inst_get_src_registers (ins, sregs);
648 for (i = 0; i < num_sregs; ++i) {
649 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
650
651 if (var) {
652 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
653
654 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
655 printf ("COALESCE: R%d -> R%d\n", sregs [i], cfg->varinfo [vmv->reg]->dreg);
656 sregs [i] = cfg->varinfo [vmv->reg]->dreg;
657 }
658 }
659 }
660 mono_inst_set_src_registers (ins, sregs);
661 }
662 }
663
664 for (i = 0; i < cfg->num_varinfo; ++i) {
665 MONO_VARINFO (cfg, i)->reg = -1;
666 }
667
668 if (cfg->comp_done & MONO_COMP_REACHABILITY)
669 unlink_unused_bblocks (cfg);
670
671 cfg->comp_done &= ~MONO_COMP_LIVENESS;
672
673 cfg->comp_done &= ~MONO_COMP_SSA;
674 }
675
676 static void
677 mono_ssa_create_def_use (MonoCompile *cfg)
678 {
679 MonoBasicBlock *bb;
680 MonoInst *ins;
681 int i;
682
683 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
684
685 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
686 for (ins = bb->code; ins; ins = ins->next) {
687 const char *spec = INS_INFO (ins->opcode);
688 MonoMethodVar *info;
689 int num_sregs;
690 int sregs [MONO_MAX_SRC_REGS];
691
692 if (ins->opcode == OP_NOP)
693 continue;
694
695 /* SREGs */
696 num_sregs = mono_inst_get_src_registers (ins, sregs);
697 for (i = 0; i < num_sregs; ++i) {
698 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
699 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
700 record_use (cfg, var, bb, ins);
701 }
702
703 if (MONO_IS_STORE_MEMBASE (ins)) {
704 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
705 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
706 record_use (cfg, var, bb, ins);
707 }
708
709 if (MONO_IS_PHI (ins)) {
710 for (i = ins->inst_phi_args [0]; i > 0; i--) {
711 g_assert (ins->inst_phi_args [i] != -1);
712 record_use (cfg, get_vreg_to_inst (cfg, ins->inst_phi_args [i]), bb, ins);
713 }
714 }
715
716 /* DREG */
717 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
718 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
719
720 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
721 info = MONO_VARINFO (cfg, var->inst_c0);
722 info->def = ins;
723 info->def_bb = bb;
724 }
725 }
726 }
727 }
728
729 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
730 }
731
732 static void
733 mono_ssa_copyprop (MonoCompile *cfg)
734 {
735 int i, index;
736 GList *l;
737
738 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
739
740 for (index = 0; index < cfg->num_varinfo; ++index) {
741 MonoInst *var = cfg->varinfo [index];
742 MonoMethodVar *info = MONO_VARINFO (cfg, index);
743
744 if (info->def && (MONO_IS_MOVE (info->def))) {
745 MonoInst *var2 = get_vreg_to_inst (cfg, info->def->sreg1);
746
747 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))) {
748 /* Rewrite all uses of var to be uses of var2 */
749 int dreg = var->dreg;
750 int sreg1 = var2->dreg;
751
752 l = info->uses;
753 while (l) {
754 MonoVarUsageInfo *u = (MonoVarUsageInfo*)l->data;
755 MonoInst *ins = u->inst;
756 GList *next = l->next;
757 int num_sregs;
758 int sregs [MONO_MAX_SRC_REGS];
759
760 num_sregs = mono_inst_get_src_registers (ins, sregs);
761 for (i = 0; i < num_sregs; ++i) {
762 if (sregs [i] == dreg)
763 break;
764 }
765 if (i < num_sregs) {
766 g_assert (sregs [i] == dreg);
767 sregs [i] = sreg1;
768 mono_inst_set_src_registers (ins, sregs);
769 } else if (MONO_IS_STORE_MEMBASE (ins) && ins->dreg == dreg) {
770 ins->dreg = sreg1;
771 } else if (MONO_IS_PHI (ins)) {
772 for (i = ins->inst_phi_args [0]; i > 0; i--) {
773 int sreg = ins->inst_phi_args [i];
774 if (sreg == var->dreg)
775 break;
776 }
777 g_assert (i > 0);
778 ins->inst_phi_args [i] = sreg1;
779 }
780 else
781 g_assert_not_reached ();
782
783 record_use (cfg, var2, u->bb, ins);
784
785 l = next;
786 }
787
788 info->uses = NULL;
789 }
790 }
791 }
792
793 if (cfg->verbose_level >= 4) {
794 MonoBasicBlock *bb;
795
796 for (bb = cfg->bb_entry; bb; bb = bb->next_bb)
797 mono_print_bb (bb, "AFTER SSA COPYPROP");
798 }
799 }
800
801 static int
802 evaluate_ins (MonoCompile *cfg, MonoInst *ins, MonoInst **res, MonoInst **carray)
803 {
804 MonoInst *args [MONO_MAX_SRC_REGS];
805 int rs [MONO_MAX_SRC_REGS];
806 MonoInst *c0;
807 gboolean const_args = TRUE;
808 const char *spec = INS_INFO (ins->opcode);
809 int num_sregs, i;
810 int sregs [MONO_MAX_SRC_REGS];
811
812 /* Short-circuit this */
813 if (ins->opcode == OP_ICONST) {
814 *res = ins;
815 return 1;
816 }
817
818 if (ins->opcode == OP_NOP)
819 return 2;
820
821 num_sregs = mono_inst_get_src_registers (ins, sregs);
822 for (i = 0; i < MONO_MAX_SRC_REGS; ++i)
823 args [i] = NULL;
824 for (i = 0; i < num_sregs; ++i) {
825 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
826
827 rs [i] = 2;
828 args [i] = carray [sregs [i]];
829 if (args [i])
830 rs [i] = 1;
831 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
832 rs [i] = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
833 if (rs [i] != 1)
834 const_args = FALSE;
835 }
836
837 c0 = NULL;
838
839 if (num_sregs > 0 && const_args) {
840 g_assert (num_sregs <= 2);
841 if ((spec [MONO_INST_DEST] != ' ') && carray [ins->dreg]) {
842 // Cached value
843 *res = carray [ins->dreg];
844 return 1;
845 }
846 c0 = mono_constant_fold_ins (cfg, ins, args [0], args [1], FALSE);
847 if (c0) {
848 if (G_UNLIKELY (cfg->verbose_level > 1)) {
849 printf ("\t cfold -> ");
850 mono_print_ins (c0);
851 }
852 *res = c0;
853 return 1;
854 }
855 else
856 /* Can't cfold this ins */
857 return 2;
858 }
859
860 if (num_sregs == 0)
861 return 2;
862 for (i = 0; i < num_sregs; ++i) {
863 if (rs [i] == 2)
864 return 2;
865 }
866 return 0;
867 }
868
869 static inline void
870 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
871 {
872 if (info->cpstate >= state)
873 return;
874
875 info->cpstate = state;
876
877 if (G_UNLIKELY (cfg->verbose_level > 1))
878 printf ("\tState of R%d set to %d\n", cfg->varinfo [info->idx]->dreg, info->cpstate);
879
880 if (state == 1)
881 g_assert (c0);
882
883 carray [cfg->varinfo [info->idx]->dreg] = c0;
884
885 if (!g_list_find (*cvars, info)) {
886 *cvars = g_list_prepend (*cvars, info);
887 }
888 }
889
890 static inline void
891 add_cprop_bb (MonoCompile *cfg, MonoBasicBlock *bb, GList **bblist)
892 {
893 if (G_UNLIKELY (cfg->verbose_level > 1))
894 printf ("\tAdd BB%d to worklist\n", bb->block_num);
895
896 if (!(bb->flags & BB_REACHABLE)) {
897 bb->flags |= BB_REACHABLE;
898 *bblist = g_list_prepend (*bblist, bb);
899 }
900 }
901
902 static void
903 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GList **cvars, GList **bblist, MonoInst **carray)
904 {
905 const char *spec = INS_INFO (ins->opcode);
906
907 if (ins->opcode == OP_NOP)
908 return;
909
910 if (cfg->verbose_level > 1)
911 mono_print_ins (ins);
912
913 /* FIXME: Support longs/floats */
914 /* FIXME: Work on vregs as well */
915
916 if (MONO_IS_PHI (ins)) {
917 MonoMethodVar *info = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, ins->dreg)->inst_c0);
918 MonoInst *c0 = NULL;
919 int j;
920
921 for (j = 1; j <= ins->inst_phi_args [0]; j++) {
922 MonoInst *var = get_vreg_to_inst (cfg, ins->inst_phi_args [j]);
923 MonoMethodVar *mv = MONO_VARINFO (cfg, var->inst_c0);
924 MonoInst *src = mv->def;
925
926 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE))
927 continue;
928
929 if (!mv->def || !src || mv->cpstate == 2) {
930 change_varstate (cfg, cvars, info, 2, NULL, carray);
931 break;
932 }
933
934 if (mv->cpstate == 0)
935 continue;
936
937 g_assert (carray [var->dreg]);
938
939 if (!c0)
940 c0 = carray [var->dreg];
941
942 /* FIXME: */
943 if (c0->opcode != OP_ICONST) {
944 change_varstate (cfg, cvars, info, 2, NULL, carray);
945 break;
946 }
947
948 if (carray [var->dreg]->inst_c0 != c0->inst_c0) {
949 change_varstate (cfg, cvars, info, 2, NULL, carray);
950 break;
951 }
952 }
953
954 if (c0 && info->cpstate < 1) {
955 change_varstate (cfg, cvars, info, 1, c0, carray);
956
957 g_assert (c0->opcode == OP_ICONST);
958 }
959 }
960 else if (!MONO_IS_STORE_MEMBASE (ins) && ((spec [MONO_INST_SRC1] != ' ') || (spec [MONO_INST_SRC2] != ' ') || (spec [MONO_INST_DEST] != ' '))) {
961 MonoInst *var, *c0;
962 int state;
963
964 if (spec [MONO_INST_DEST] != ' ')
965 var = get_vreg_to_inst (cfg, ins->dreg);
966 else
967 var = NULL;
968
969 c0 = NULL;
970 state = evaluate_ins (cfg, ins, &c0, carray);
971
972 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
973 MonoMethodVar *info = MONO_VARINFO (cfg, var->inst_c0);
974
975 if (info->cpstate < 2) {
976 if (state == 1)
977 change_varstate (cfg, cvars, info, 1, c0, carray);
978 else if (state == 2)
979 change_varstate (cfg, cvars, info, 2, NULL, carray);
980 }
981 }
982 else if (!var && (ins->dreg != -1)) {
983 /*
984 * We don't record def-use information for local vregs since it would be
985 * expensive. Instead, we depend on the fact that all uses of the vreg are in
986 * the same bblock, so they will be examined after the definition.
987 * FIXME: This isn't true if the ins is visited through an SSA edge.
988 */
989 if (c0) {
990 carray [ins->dreg] = c0;
991 } else {
992 if (carray [ins->dreg]) {
993 /*
994 * The state of the vreg changed from constant to non-constant
995 * -> need to rescan the whole bblock.
996 */
997 carray [ins->dreg] = NULL;
998 /* FIXME: Speed this up */
999
1000 if (!g_list_find (*bblist, bb))
1001 *bblist = g_list_prepend (*bblist, bb);
1002 }
1003 }
1004 }
1005
1006 if (MONO_IS_JUMP_TABLE (ins)) {
1007 int i;
1008 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1009
1010 if (!ins->next || ins->next->opcode != OP_PADD) {
1011 /* The PADD was optimized away */
1012 /* FIXME: handle this as well */
1013 for (i = 0; i < table->table_size; i++)
1014 if (table->table [i])
1015 add_cprop_bb (cfg, table->table [i], bblist);
1016 return;
1017 }
1018
1019 g_assert (ins->next->opcode == OP_PADD);
1020 g_assert (ins->next->sreg1 == ins->dreg);
1021
1022 if (carray [ins->next->sreg2]) {
1023 #if SIZEOF_REGISTER == 8
1024 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1025 #else
1026 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1027 #endif
1028 if ((idx < 0) || (idx >= table->table_size))
1029 /* Out-of-range, no branch is executed */
1030 return;
1031 else
1032 if (table->table [idx])
1033 add_cprop_bb (cfg, table->table [idx], bblist);
1034 }
1035 else {
1036 for (i = 0; i < table->table_size; i++)
1037 if (table->table [i])
1038 add_cprop_bb (cfg, table->table [i], bblist);
1039 }
1040 }
1041
1042 if (ins->opcode == OP_SWITCH) {
1043 int i;
1044 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)ins->inst_p0;
1045
1046 for (i = 0; i < table->table_size; i++)
1047 if (table->table [i])
1048 add_cprop_bb (cfg, table->table [i], bblist);
1049 }
1050
1051 /* Handle COMPARE+BRCOND pairs */
1052 if (ins->next && MONO_IS_COND_BRANCH_OP (ins->next)) {
1053 if (c0) {
1054 g_assert (c0->opcode == OP_ICONST);
1055
1056 if (c0->inst_c0)
1057 ins->next->flags |= MONO_INST_CFOLD_TAKEN;
1058 else
1059 ins->next->flags |= MONO_INST_CFOLD_NOT_TAKEN;
1060 }
1061 else {
1062 ins->next->flags &= ~(MONO_INST_CFOLD_TAKEN | MONO_INST_CFOLD_NOT_TAKEN);
1063 }
1064
1065 visit_inst (cfg, bb, ins->next, cvars, bblist, carray);
1066 }
1067 } else if (ins->opcode == OP_BR) {
1068 add_cprop_bb (cfg, ins->inst_target_bb, bblist);
1069 } else if (MONO_IS_COND_BRANCH_OP (ins)) {
1070 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1071 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1072 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1073 if (ins->inst_false_bb)
1074 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1075 } else {
1076 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1077 if (ins->inst_false_bb)
1078 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1079 }
1080 }
1081 }
1082
1083 /**
1084 * fold_ins:
1085 *
1086 * Replace INS with its constant value, if it exists
1087 */
1088 static void
1089 fold_ins (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, MonoInst **carray)
1090 {
1091 const char *spec = INS_INFO (ins->opcode);
1092 int opcode2;
1093 int num_sregs = mono_inst_get_num_src_registers (ins);
1094
1095 if ((ins->opcode != OP_NOP) && (ins->dreg != -1) && !MONO_IS_STORE_MEMBASE (ins)) {
1096 if (carray [ins->dreg] && (spec [MONO_INST_DEST] == 'i') && (ins->dreg >= MONO_MAX_IREGS)) {
1097 /* Perform constant folding */
1098 /* FIXME: */
1099 g_assert (carray [ins->dreg]->opcode == OP_ICONST);
1100 ins->opcode = OP_ICONST;
1101 ins->inst_c0 = carray [ins->dreg]->inst_c0;
1102 MONO_INST_NULLIFY_SREGS (ins);
1103 } else if (num_sregs == 2 && carray [ins->sreg2]) {
1104 /* Perform op->op_imm conversion */
1105 opcode2 = mono_op_to_op_imm (ins->opcode);
1106 if (opcode2 != -1) {
1107 ins->opcode = opcode2;
1108 ins->inst_imm = carray [ins->sreg2]->inst_c0;
1109 ins->sreg2 = -1;
1110
1111 if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
1112 ((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
1113 }
1114 } else {
1115 /* FIXME: Handle 3 op insns */
1116 }
1117
1118 if (MONO_IS_JUMP_TABLE (ins)) {
1119 int i;
1120 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1121
1122 if (!ins->next || ins->next->opcode != OP_PADD) {
1123 /* The PADD was optimized away */
1124 /* FIXME: handle this as well */
1125 return;
1126 }
1127
1128 g_assert (ins->next->opcode == OP_PADD);
1129 g_assert (ins->next->sreg1 == ins->dreg);
1130 g_assert (ins->next->next->opcode == OP_LOAD_MEMBASE);
1131
1132 if (carray [ins->next->sreg2]) {
1133 /* Convert to a simple branch */
1134 #if SIZEOF_REGISTER == 8
1135 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1136 #else
1137 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1138 #endif
1139
1140 if (!((idx >= 0) && (idx < table->table_size))) {
1141 /* Out of range, eliminate the whole switch */
1142 for (i = 0; i < table->table_size; ++i) {
1143 remove_bb_from_phis (cfg, bb, table->table [i]);
1144 mono_unlink_bblock (cfg, bb, table->table [i]);
1145 }
1146
1147 NULLIFY_INS (ins);
1148 NULLIFY_INS (ins->next);
1149 NULLIFY_INS (ins->next->next);
1150 if (ins->next->next->next)
1151 NULLIFY_INS (ins->next->next->next);
1152
1153 return;
1154 }
1155
1156 if (!ins->next->next->next || ins->next->next->next->opcode != OP_BR_REG) {
1157 /* A one-way switch which got optimized away */
1158 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1159 printf ("\tNo cfold on ");
1160 mono_print_ins (ins);
1161 }
1162 return;
1163 }
1164
1165 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1166 printf ("\tcfold on ");
1167 mono_print_ins (ins);
1168 }
1169
1170 /* Unlink target bblocks */
1171 for (i = 0; i < table->table_size; ++i) {
1172 if (table->table [i] != table->table [idx]) {
1173 remove_bb_from_phis (cfg, bb, table->table [i]);
1174 mono_unlink_bblock (cfg, bb, table->table [i]);
1175 }
1176 }
1177
1178 /* Change the OP_BR_REG to a simple branch */
1179 ins->next->next->next->opcode = OP_BR;
1180 ins->next->next->next->inst_target_bb = table->table [idx];
1181 ins->next->next->next->sreg1 = -1;
1182
1183 /* Nullify the other instructions */
1184 NULLIFY_INS (ins);
1185 NULLIFY_INS (ins->next);
1186 NULLIFY_INS (ins->next->next);
1187 }
1188 }
1189 }
1190 else if (MONO_IS_COND_BRANCH_OP (ins)) {
1191 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1192 remove_bb_from_phis (cfg, bb, ins->inst_false_bb);
1193 mono_unlink_bblock (cfg, bb, ins->inst_false_bb);
1194 ins->opcode = OP_BR;
1195 ins->inst_target_bb = ins->inst_true_bb;
1196 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1197 remove_bb_from_phis (cfg, bb, ins->inst_true_bb);
1198 mono_unlink_bblock (cfg, bb, ins->inst_true_bb);
1199 ins->opcode = OP_BR;
1200 ins->inst_target_bb = ins->inst_false_bb;
1201 }
1202 }
1203 }
1204
1205 void
1206 mono_ssa_cprop (MonoCompile *cfg)
1207 {
1208 MonoInst **carray;
1209 MonoBasicBlock *bb;
1210 GList *bblock_list, *cvars;
1211 GList *tmp;
1212 int i;
1213 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1214
1215 carray = g_new0 (MonoInst*, cfg->next_vreg);
1216
1217 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1218 mono_ssa_create_def_use (cfg);
1219
1220 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1221 cfg->bb_entry->flags |= BB_REACHABLE;
1222
1223 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1224
1225 for (i = 0; i < cfg->num_varinfo; i++) {
1226 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1227 if (!info->def)
1228 info->cpstate = 2;
1229 }
1230
1231 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1232 /*
1233 * FIXME: This should be bb->flags & BB_FLAG_EXCEPTION_HANDLER, but
1234 * that would still allow unreachable try's to be removed.
1235 */
1236 if (bb->region)
1237 add_cprop_bb (cfg, bb, &bblock_list);
1238 }
1239
1240 cvars = NULL;
1241
1242 while (bblock_list) {
1243 MonoInst *inst;
1244
1245 bb = (MonoBasicBlock *)bblock_list->data;
1246
1247 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1248
1249 g_assert (bb->flags & BB_REACHABLE);
1250
1251 /*
1252 * Some bblocks are linked to 2 others even through they fall through to the
1253 * next bblock.
1254 */
1255 if (!(bb->last_ins && MONO_IS_BRANCH_OP (bb->last_ins))) {
1256 for (i = 0; i < bb->out_count; ++i)
1257 add_cprop_bb (cfg, bb->out_bb [i], &bblock_list);
1258 }
1259
1260 if (cfg->verbose_level > 1)
1261 printf ("\nSSA CONSPROP BB%d:\n", bb->block_num);
1262
1263 for (inst = bb->code; inst; inst = inst->next) {
1264 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1265 }
1266
1267 while (cvars) {
1268 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1269 cvars = g_list_delete_link (cvars, cvars);
1270
1271 for (tmp = info->uses; tmp; tmp = tmp->next) {
1272 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1273 if (!(ui->bb->flags & BB_REACHABLE))
1274 continue;
1275 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1276 }
1277 }
1278 }
1279
1280 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1281 MonoInst *inst;
1282 for (inst = bb->code; inst; inst = inst->next) {
1283 fold_ins (cfg, bb, inst, carray);
1284 }
1285 }
1286
1287 g_free (carray);
1288
1289 cfg->comp_done |= MONO_COMP_REACHABILITY;
1290
1291 /* fixme: we should update usage infos during cprop, instead of computing it again */
1292 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1293 for (i = 0; i < cfg->num_varinfo; i++) {
1294 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1295 info->def = NULL;
1296 info->uses = NULL;
1297 }
1298 }
1299
1300 static inline void
1301 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1302 {
1303 GList *tmp;
1304
1305 *wl = g_list_prepend_mempool (cfg->mempool, *wl, use);
1306
1307 for (tmp = use->uses; tmp; tmp = tmp->next) {
1308 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1309 if (ui->inst == var->def) {
1310 /* from the mempool */
1311 use->uses = g_list_remove_link (use->uses, tmp);
1312 break;
1313 }
1314 }
1315 }
1316
1317 void
1318 mono_ssa_deadce (MonoCompile *cfg)
1319 {
1320 int i;
1321 GList *work_list;
1322
1323 g_assert (cfg->comp_done & MONO_COMP_SSA);
1324
1325 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1326
1327 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1328 mono_ssa_create_def_use (cfg);
1329
1330 mono_ssa_copyprop (cfg);
1331
1332 work_list = NULL;
1333 for (i = 0; i < cfg->num_varinfo; i++) {
1334 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1335 work_list = g_list_prepend_mempool (cfg->mempool, work_list, info);
1336 }
1337
1338 while (work_list) {
1339 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1340 work_list = g_list_remove_link (work_list, work_list);
1341
1342 /*
1343 * The second part of the condition happens often when PHI nodes have their dreg
1344 * as one of their arguments due to the fact that we use the original vars.
1345 */
1346 if (info->def && (!info->uses || ((info->uses->next == NULL) && (((MonoVarUsageInfo*)info->uses->data)->inst == info->def)))) {
1347 MonoInst *def = info->def;
1348
1349 /* Eliminating FMOVE could screw up the fp stack */
1350 if (MONO_IS_MOVE (def) && (!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE))) {
1351 MonoInst *src_var = get_vreg_to_inst (cfg, def->sreg1);
1352 if (src_var && !(src_var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1353 add_to_dce_worklist (cfg, info, MONO_VARINFO (cfg, src_var->inst_c0), &work_list);
1354 NULLIFY_INS (def);
1355 info->reg = -1;
1356 } else if ((def->opcode == OP_ICONST) || (def->opcode == OP_I8CONST) || MONO_IS_ZERO (def)) {
1357 NULLIFY_INS (def);
1358 info->reg = -1;
1359 } else if (MONO_IS_PHI (def)) {
1360 int j;
1361 for (j = def->inst_phi_args [0]; j > 0; j--) {
1362 MonoMethodVar *u = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, def->inst_phi_args [j])->inst_c0);
1363 add_to_dce_worklist (cfg, info, u, &work_list);
1364 }
1365 NULLIFY_INS (def);
1366 info->reg = -1;
1367 }
1368 else if (def->opcode == OP_NOP) {
1369 }
1370 //else
1371 //mono_print_ins (def);
1372 }
1373
1374 }
1375 }
1376
1377 #if 0
1378 void
1379 mono_ssa_strength_reduction (MonoCompile *cfg)
1380 {
1381 MonoBasicBlock *bb;
1382 int i;
1383
1384 g_assert (cfg->comp_done & MONO_COMP_SSA);
1385 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1386 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1387
1388 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1389 GList *lp = bb->loop_blocks;
1390
1391 if (lp) {
1392 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1393
1394 /* we only consider loops with 2 in bblocks */
1395 if (!h->in_count == 2)
1396 continue;
1397
1398 for (i = 0; i < cfg->num_varinfo; i++) {
1399 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1400
1401 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1402 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1403 MonoInst *v = info->def->inst_i1;
1404
1405
1406 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1407 }
1408 }
1409 }
1410 }
1411 }
1412 #endif
1413
1414 void
1415 mono_ssa_loop_invariant_code_motion (MonoCompile *cfg)
1416 {
1417 MonoBasicBlock *bb, *h, *idom;
1418 MonoInst *ins, *n, *tins;
1419 int i;
1420
1421 g_assert (cfg->comp_done & MONO_COMP_SSA);
1422 if (!(cfg->comp_done & MONO_COMP_LOOPS) || !(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1423 return;
1424
1425 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1426 GList *lp = bb->loop_blocks;
1427
1428 if (!lp)
1429 continue;
1430 h = (MonoBasicBlock *)lp->data;
1431 if (bb != h)
1432 continue;
1433 MONO_BB_FOR_EACH_INS_SAFE (bb, n, ins) {
1434 /*
1435 * Try to move instructions out of loop headers into the preceeding bblock.
1436 */
1437 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS || ins->opcode == OP_AOTCONST || ins->opcode == OP_GENERIC_CLASS_INIT) {
1438 gboolean skip;
1439 int sreg;
1440
1441 idom = h->idom;
1442 /*
1443 * h->nesting is needed to work around:
1444 * http://llvm.org/bugs/show_bug.cgi?id=17868
1445 */
1446 if (!(idom && idom->last_ins && idom->last_ins->opcode == OP_BR && idom->last_ins->inst_target_bb == h && h->nesting == 1)) {
1447 continue;
1448 }
1449
1450 /*
1451 * Make sure there are no instructions with side effects before ins.
1452 */
1453 skip = FALSE;
1454 MONO_BB_FOR_EACH_INS (bb, tins) {
1455 if (tins == ins)
1456 break;
1457 if (!MONO_INS_HAS_NO_SIDE_EFFECT (tins)) {
1458 skip = TRUE;
1459 break;
1460 }
1461 }
1462 if (skip) {
1463 /*
1464 printf ("%s\n", mono_method_full_name (cfg->method, TRUE));
1465 mono_print_ins (tins);
1466 */
1467 continue;
1468 }
1469
1470 /* Make sure we don't move the instruction before the def of its sreg */
1471 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS)
1472 sreg = ins->sreg1;
1473 else
1474 sreg = -1;
1475 if (sreg != -1) {
1476 MonoInst *tins, *var;
1477
1478 skip = FALSE;
1479 for (tins = ins->prev; tins; tins = tins->prev) {
1480 const char *spec = INS_INFO (tins->opcode);
1481
1482 if (tins->opcode == OP_MOVE && tins->dreg == sreg) {
1483 sreg = tins->sreg1;
1484 } if (spec [MONO_INST_DEST] != ' ' && tins->dreg == sreg) {
1485 skip = TRUE;
1486 break;
1487 }
1488 }
1489 if (skip)
1490 continue;
1491 var = get_vreg_to_inst (cfg, sreg);
1492 if (var && (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1493 continue;
1494 ins->sreg1 = sreg;
1495 }
1496
1497 if (cfg->verbose_level > 1) {
1498 printf ("licm in BB%d on ", bb->block_num);
1499 mono_print_ins (ins);
1500 }
1501 //{ static int count = 0; count ++; printf ("%d\n", count); }
1502 MONO_REMOVE_INS (bb, ins);
1503 mono_bblock_insert_before_ins (idom, idom->last_ins, ins);
1504 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN)
1505 idom->has_array_access = TRUE;
1506 }
1507 }
1508 }
1509
1510 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1511 for (i = 0; i < cfg->num_varinfo; i++) {
1512 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1513 info->def = NULL;
1514 info->uses = NULL;
1515 }
1516 }
1517
1518 #endif /* DISABLE_JIT */
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