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[ci] Bump timeout in ms-test-suite
[mono-project.git] / mono / mini / ssa.c
blobd70788c6afb39ce430fcde647838b3ca7689e66b
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 #include <mono/utils/mono-compiler.h>
17
18 #ifndef DISABLE_JIT
19
20 #include "mini.h"
21 #ifdef HAVE_ALLOCA_H
22 #include <alloca.h>
23 #endif
24
25 #define CREATE_PRUNED_SSA
26
27 //#define DEBUG_SSA 1
28
29 #define NEW_PHI(cfg,dest,val) do { \
30 MONO_INST_NEW ((cfg), (dest), OP_PHI); \
31 (dest)->inst_c0 = (val); \
32 } while (0)
33
34 typedef struct {
35 MonoBasicBlock *bb;
36 MonoInst *inst;
37 } MonoVarUsageInfo;
38
39 static void
40 unlink_target (MonoBasicBlock *bb, MonoBasicBlock *target)
41 {
42 int i;
43
44 for (i = 0; i < bb->out_count; i++) {
45 if (bb->out_bb [i] == target) {
46 bb->out_bb [i] = bb->out_bb [--bb->out_count];
47 break;
48 }
49 }
50 for (i = 0; i < target->in_count; i++) {
51 if (target->in_bb [i] == bb) {
52 target->in_bb [i] = target->in_bb [--target->in_count];
53 break;
54
55 }
56 }
57 }
58
59 static void
60 unlink_unused_bblocks (MonoCompile *cfg)
61 {
62 int i, j;
63 MonoBasicBlock *bb;
64
65 g_assert (cfg->comp_done & MONO_COMP_REACHABILITY);
66
67 if (G_UNLIKELY (cfg->verbose_level > 1))
68 printf ("\nUNLINK UNUSED BBLOCKS:\n");
69
70 for (bb = cfg->bb_entry; bb && bb->next_bb;) {
71 if (!(bb->next_bb->flags & BB_REACHABLE)) {
72 bb->next_bb = bb->next_bb->next_bb;
73 } else
74 bb = bb->next_bb;
75 }
76
77 for (i = 1; i < cfg->num_bblocks; i++) {
78 bb = cfg->bblocks [i];
79
80 if (!(bb->flags & BB_REACHABLE)) {
81 for (j = 0; j < bb->in_count; j++) {
82 unlink_target (bb->in_bb [j], bb);
83 }
84 for (j = 0; j < bb->out_count; j++) {
85 unlink_target (bb, bb->out_bb [j]);
86 }
87 if (G_UNLIKELY (cfg->verbose_level > 1))
88 printf ("\tUnlinked BB%d\n", bb->block_num);
89 }
90
91 }
92 }
93
94 /**
95 * remove_bb_from_phis:
96 *
97 * Remove BB from the PHI statements in TARGET.
98 */
99 static void
100 remove_bb_from_phis (MonoCompile *cfg, MonoBasicBlock *bb, MonoBasicBlock *target)
101 {
102 MonoInst *ins;
103 int i, j;
104
105 for (i = 0; i < target->in_count; i++) {
106 if (target->in_bb [i] == bb) {
107 break;
108 }
109 }
110 g_assert (i < target->in_count);
111
112 for (ins = target->code; ins; ins = ins->next) {
113 if (MONO_IS_PHI (ins)) {
114 for (j = i; j < ins->inst_phi_args [0] - 1; ++j)
115 ins->inst_phi_args [j + 1] = ins->inst_phi_args [j + 2];
116 ins->inst_phi_args [0] --;
117 }
118 else
119 break;
120 }
121 }
122
123 static inline int
124 op_phi_to_move (int opcode)
125 {
126 switch (opcode) {
127 case OP_PHI:
128 return OP_MOVE;
129 case OP_FPHI:
130 return OP_FMOVE;
131 case OP_VPHI:
132 return OP_VMOVE;
133 case OP_XPHI:
134 return OP_XMOVE;
135 default:
136 g_assert_not_reached ();
137 }
138
139 return -1;
140 }
141
142 static inline void
143 record_use (MonoCompile *cfg, MonoInst *var, MonoBasicBlock *bb, MonoInst *ins)
144 {
145 MonoMethodVar *info;
146 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)mono_mempool_alloc (cfg->mempool, sizeof (MonoVarUsageInfo));
147
148 info = MONO_VARINFO (cfg, var->inst_c0);
149
150 ui->bb = bb;
151 ui->inst = ins;
152 info->uses = g_list_prepend_mempool (cfg->mempool, info->uses, ui);
153 }
154
155 typedef struct {
156 MonoInst *var;
157 int idx;
158 } RenameInfo;
159
160 /**
161 * mono_ssa_rename_vars:
162 *
163 * Implement renaming of SSA variables. Also compute def-use information in parallel.
164 * @stack_history points to an area of memory which can be used for storing changes
165 * made to the stack, so they can be reverted later.
166 */
167 static void
168 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)
169 {
170 MonoInst *ins, *new_var;
171 int i, j, idx;
172 GSList *tmp;
173 int stack_history_len = 0;
174
175 if (cfg->verbose_level >= 4)
176 printf ("\nRENAME VARS BLOCK %d:\n", bb->block_num);
177
178 /* First pass: Create new vars */
179 for (ins = bb->code; ins; ins = ins->next) {
180 const char *spec = INS_INFO (ins->opcode);
181 int num_sregs;
182 int sregs [MONO_MAX_SRC_REGS];
183
184 #ifdef DEBUG_SSA
185 printf ("\tProcessing "); mono_print_ins (ins);
186 #endif
187 if (ins->opcode == OP_NOP)
188 continue;
189
190 /* SREGs */
191 num_sregs = mono_inst_get_src_registers (ins, sregs);
192 for (i = 0; i < num_sregs; ++i) {
193 if (spec [MONO_INST_SRC1 + i] != ' ') {
194 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
195 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
196 int idx = var->inst_c0;
197 if (stack [idx]) {
198 if (var->opcode != OP_ARG)
199 g_assert (stack [idx]);
200 sregs [i] = stack [idx]->dreg;
201 record_use (cfg, stack [idx], bb, ins);
202 }
203 else
204 record_use (cfg, var, bb, ins);
205 }
206 else if (G_UNLIKELY (!var && lvreg_stack [sregs [i]]))
207 sregs [i] = lvreg_stack [sregs [i]];
208 }
209 }
210 mono_inst_set_src_registers (ins, sregs);
211
212 if (MONO_IS_STORE_MEMBASE (ins)) {
213 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
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 ins->dreg = stack [idx]->dreg;
220 record_use (cfg, stack [idx], bb, ins);
221 }
222 else
223 record_use (cfg, var, bb, ins);
224 }
225 else if (G_UNLIKELY (!var && lvreg_stack [ins->dreg]))
226 ins->dreg = lvreg_stack [ins->dreg];
227 }
228
229 /* DREG */
230 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
231 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
232 MonoMethodVar *info;
233
234 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
235 idx = var->inst_c0;
236 g_assert (idx < max_vars);
237
238 if (var->opcode == OP_ARG)
239 originals_used [idx] = TRUE;
240
241 /* FIXME: */
242 g_assert (stack_history_len < stack_history_size);
243 stack_history [stack_history_len].var = stack [idx];
244 stack_history [stack_history_len].idx = idx;
245 stack_history_len ++;
246
247 if (originals_used [idx]) {
248 new_var = mono_compile_create_var (cfg, var->inst_vtype, OP_LOCAL);
249 new_var->flags = var->flags;
250 MONO_VARINFO (cfg, new_var->inst_c0)->reg = idx;
251
252 if (cfg->verbose_level >= 4)
253 printf (" R%d -> R%d\n", var->dreg, new_var->dreg);
254
255 stack [idx] = new_var;
256
257 ins->dreg = new_var->dreg;
258 var = new_var;
259 }
260 else {
261 stack [idx] = var;
262 originals_used [idx] = TRUE;
263 }
264
265 info = MONO_VARINFO (cfg, var->inst_c0);
266 info->def = ins;
267 info->def_bb = bb;
268 }
269 else if (G_UNLIKELY (!var && lvreg_defined [ins->dreg] && (ins->dreg >= MONO_MAX_IREGS))) {
270 /* Perform renaming for local vregs */
271 lvreg_stack [ins->dreg] = vreg_is_ref (cfg, ins->dreg) ? mono_alloc_ireg_ref (cfg) : mono_alloc_preg (cfg);
272 ins->dreg = lvreg_stack [ins->dreg];
273 }
274 else
275 lvreg_defined [ins->dreg] = TRUE;
276 }
277
278 #ifdef DEBUG_SSA
279 printf ("\tAfter processing "); mono_print_ins (ins);
280 #endif
281
282 }
283
284 /* Rename PHI arguments in succeeding bblocks */
285 for (i = 0; i < bb->out_count; i++) {
286 MonoBasicBlock *n = bb->out_bb [i];
287
288 for (j = 0; j < n->in_count; j++)
289 if (n->in_bb [j] == bb)
290 break;
291
292 for (ins = n->code; ins; ins = ins->next) {
293 if (MONO_IS_PHI (ins)) {
294 idx = ins->inst_c0;
295 if (stack [idx])
296 new_var = stack [idx];
297 else
298 new_var = cfg->varinfo [idx];
299 #ifdef DEBUG_SSA
300 printf ("FOUND PHI %d (%d, %d)\n", idx, j, new_var->inst_c0);
301 #endif
302 ins->inst_phi_args [j + 1] = new_var->dreg;
303 record_use (cfg, new_var, n, ins);
304 if (G_UNLIKELY (cfg->verbose_level >= 4))
305 printf ("\tAdd PHI R%d <- R%d to BB%d\n", ins->dreg, new_var->dreg, n->block_num);
306 }
307 else
308 /* The phi nodes are at the beginning of the bblock */
309 break;
310 }
311 }
312
313 if (bb->dominated) {
314 for (tmp = bb->dominated; tmp; tmp = tmp->next) {
315 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);
316 }
317 }
318
319 /* Restore stack */
320 for (i = stack_history_len - 1; i >= 0; i--) {
321 stack [stack_history [i].idx] = stack_history [i].var;
322 }
323
324 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
325 }
326
327 void
328 mono_ssa_compute (MonoCompile *cfg)
329 {
330 int i, j, idx, bitsize;
331 MonoBitSet *set;
332 MonoMethodVar *vinfo = g_new0 (MonoMethodVar, cfg->num_varinfo);
333 MonoInst *ins, **stack;
334 guint8 *buf, *buf_start;
335 RenameInfo *stack_history;
336 int stack_history_size;
337 gboolean *originals;
338 guint32 *lvreg_stack;
339 gboolean *lvreg_defined;
340
341 g_assert (!(cfg->comp_done & MONO_COMP_SSA));
342
343 g_assert (!cfg->disable_ssa);
344
345 if (cfg->verbose_level >= 4)
346 printf ("\nCOMPUTE SSA %d (R%d-)\n\n", cfg->num_varinfo, cfg->next_vreg);
347
348 #ifdef CREATE_PRUNED_SSA
349 /* we need liveness for pruned SSA */
350 if (!(cfg->comp_done & MONO_COMP_LIVENESS))
351 mono_analyze_liveness (cfg);
352 #endif
353
354 mono_compile_dominator_info (cfg, MONO_COMP_DOM | MONO_COMP_IDOM | MONO_COMP_DFRONTIER);
355
356 bitsize = mono_bitset_alloc_size (cfg->num_bblocks, 0);
357 buf = buf_start = (guint8 *)g_malloc0 (mono_bitset_alloc_size (cfg->num_bblocks, 0) * cfg->num_varinfo);
358
359 for (i = 0; i < cfg->num_varinfo; ++i) {
360 vinfo [i].def_in = mono_bitset_mem_new (buf, cfg->num_bblocks, 0);
361 buf += bitsize;
362 vinfo [i].idx = i;
363 /* implicit reference at start */
364 if (cfg->varinfo [i]->opcode == OP_ARG)
365 mono_bitset_set_fast (vinfo [i].def_in, 0);
366 }
367
368 for (i = 0; i < cfg->num_bblocks; ++i) {
369 MONO_BB_FOR_EACH_INS (cfg->bblocks [i], ins) {
370 if (ins->opcode == OP_NOP)
371 continue;
372
373 if (!MONO_IS_STORE_MEMBASE (ins) && get_vreg_to_inst (cfg, ins->dreg)) {
374 mono_bitset_set_fast (vinfo [get_vreg_to_inst (cfg, ins->dreg)->inst_c0].def_in, i);
375 }
376 }
377 }
378
379 /* insert phi functions */
380 for (i = 0; i < cfg->num_varinfo; ++i) {
381 MonoInst *var = cfg->varinfo [i];
382
383 #if SIZEOF_REGISTER == 4
384 if (var->type == STACK_I8 && !COMPILE_LLVM (cfg))
385 continue;
386 #endif
387 if (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))
388 continue;
389
390 /* Most variables have only one definition */
391 if (mono_bitset_count (vinfo [i].def_in) <= 1)
392 continue;
393
394 set = mono_compile_iterated_dfrontier (cfg, vinfo [i].def_in);
395
396 if (cfg->verbose_level >= 4) {
397 if (mono_bitset_count (set) > 0) {
398 printf ("\tR%d needs PHI functions in ", var->dreg);
399 mono_blockset_print (cfg, set, "", -1);
400 }
401 }
402
403 mono_bitset_foreach_bit (set, idx, cfg->num_bblocks) {
404 MonoBasicBlock *bb = cfg->bblocks [idx];
405
406 /* fixme: create pruned SSA? we would need liveness information for that */
407
408 if (bb == cfg->bb_exit && !COMPILE_LLVM (cfg))
409 continue;
410
411 if ((cfg->comp_done & MONO_COMP_LIVENESS) && !mono_bitset_test_fast (bb->live_in_set, i)) {
412 //printf ("%d is not live in BB%d %s\n", i, bb->block_num, mono_method_full_name (cfg->method, TRUE));
413 continue;
414 }
415
416 NEW_PHI (cfg, ins, i);
417
418 switch (var->type) {
419 case STACK_I4:
420 case STACK_I8:
421 case STACK_PTR:
422 case STACK_MP:
423 case STACK_OBJ:
424 ins->opcode = OP_PHI;
425 break;
426 case STACK_R8:
427 ins->opcode = OP_FPHI;
428 break;
429 case STACK_VTYPE:
430 ins->opcode = MONO_CLASS_IS_SIMD (cfg, var->klass) ? OP_XPHI : OP_VPHI;
431 break;
432 }
433
434 if (var->inst_vtype->byref)
435 ins->klass = mono_defaults.int_class;
436 else
437 ins->klass = var->klass;
438
439 ins->inst_phi_args = (int *)mono_mempool_alloc0 (cfg->mempool, sizeof (int) * (cfg->bblocks [idx]->in_count + 1));
440 ins->inst_phi_args [0] = cfg->bblocks [idx]->in_count;
441
442 /* For debugging */
443 for (j = 0; j < cfg->bblocks [idx]->in_count; ++j)
444 ins->inst_phi_args [j + 1] = -1;
445
446 ins->dreg = cfg->varinfo [i]->dreg;
447
448 mono_bblock_insert_before_ins (bb, bb->code, ins);
449
450 #ifdef DEBUG_SSA
451 printf ("ADD PHI BB%d %s\n", cfg->bblocks [idx]->block_num, mono_method_full_name (cfg->method, TRUE));
452 #endif
453 }
454 }
455
456 /* free the stuff */
457 g_free (vinfo);
458 g_free (buf_start);
459
460 /* Renaming phase */
461
462 stack = (MonoInst **)alloca (sizeof (MonoInst *) * cfg->num_varinfo);
463 memset (stack, 0, sizeof (MonoInst *) * cfg->num_varinfo);
464
465 lvreg_stack = g_new0 (guint32, cfg->next_vreg);
466 lvreg_defined = g_new0 (gboolean, cfg->next_vreg);
467 stack_history_size = 10240;
468 stack_history = g_new (RenameInfo, stack_history_size);
469 originals = g_new0 (gboolean, cfg->num_varinfo);
470 mono_ssa_rename_vars (cfg, cfg->num_varinfo, cfg->bb_entry, originals, stack, lvreg_stack, lvreg_defined, stack_history, stack_history_size);
471 g_free (stack_history);
472 g_free (originals);
473 g_free (lvreg_stack);
474 g_free (lvreg_defined);
475
476 if (cfg->verbose_level >= 4)
477 printf ("\nEND COMPUTE SSA.\n\n");
478
479 cfg->comp_done |= MONO_COMP_SSA;
480 }
481
482 /*
483 * mono_ssa_remove_gsharedvt:
484 *
485 * Same as mono_ssa_remove, but only remove phi nodes for gsharedvt variables.
486 */
487 void
488 mono_ssa_remove_gsharedvt (MonoCompile *cfg)
489 {
490 MonoInst *ins, *var, *move;
491 int i, j, first;
492
493 /*
494 * When compiling gsharedvt code, we need to get rid of the VPHI instructions,
495 * since they cannot be handled later in the llvm backend.
496 */
497 g_assert (cfg->comp_done & MONO_COMP_SSA);
498
499 for (i = 0; i < cfg->num_bblocks; ++i) {
500 MonoBasicBlock *bb = cfg->bblocks [i];
501
502 if (cfg->verbose_level >= 4)
503 printf ("\nREMOVE SSA %d:\n", bb->block_num);
504
505 for (ins = bb->code; ins; ins = ins->next) {
506 if (!(MONO_IS_PHI (ins) && ins->opcode == OP_VPHI && mini_is_gsharedvt_variable_type (&ins->klass->byval_arg)))
507 continue;
508
509 g_assert (ins->inst_phi_args [0] == bb->in_count);
510 var = get_vreg_to_inst (cfg, ins->dreg);
511
512 /* Check for PHI nodes where all the inputs are the same */
513 first = ins->inst_phi_args [1];
514
515 for (j = 1; j < bb->in_count; ++j)
516 if (first != ins->inst_phi_args [j + 1])
517 break;
518
519 if ((bb->in_count > 1) && (j == bb->in_count)) {
520 ins->opcode = op_phi_to_move (ins->opcode);
521 if (ins->opcode == OP_VMOVE)
522 g_assert (ins->klass);
523 ins->sreg1 = first;
524 } else {
525 for (j = 0; j < bb->in_count; j++) {
526 MonoBasicBlock *pred = bb->in_bb [j];
527 int sreg = ins->inst_phi_args [j + 1];
528
529 if (cfg->verbose_level >= 4)
530 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
531 if (var->dreg != sreg) {
532 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
533 if (move->opcode == OP_VMOVE) {
534 g_assert (ins->klass);
535 move->klass = ins->klass;
536 }
537 move->dreg = var->dreg;
538 move->sreg1 = sreg;
539 mono_add_ins_to_end (pred, move);
540 }
541 }
542
543 NULLIFY_INS (ins);
544 }
545 }
546 }
547 }
548
549 void
550 mono_ssa_remove (MonoCompile *cfg)
551 {
552 MonoInst *ins, *var, *move;
553 int bbindex, i, j, first;
554
555 g_assert (cfg->comp_done & MONO_COMP_SSA);
556
557 for (i = 0; i < cfg->num_bblocks; ++i) {
558 MonoBasicBlock *bb = cfg->bblocks [i];
559
560 if (cfg->verbose_level >= 4)
561 printf ("\nREMOVE SSA %d:\n", bb->block_num);
562
563 for (ins = bb->code; ins; ins = ins->next) {
564 if (MONO_IS_PHI (ins)) {
565 g_assert (ins->inst_phi_args [0] == bb->in_count);
566 var = get_vreg_to_inst (cfg, ins->dreg);
567
568 /* Check for PHI nodes where all the inputs are the same */
569 first = ins->inst_phi_args [1];
570
571 for (j = 1; j < bb->in_count; ++j)
572 if (first != ins->inst_phi_args [j + 1])
573 break;
574
575 if ((bb->in_count > 1) && (j == bb->in_count)) {
576 ins->opcode = op_phi_to_move (ins->opcode);
577 if (ins->opcode == OP_VMOVE)
578 g_assert (ins->klass);
579 ins->sreg1 = first;
580 } else {
581 for (j = 0; j < bb->in_count; j++) {
582 MonoBasicBlock *pred = bb->in_bb [j];
583 int sreg = ins->inst_phi_args [j + 1];
584
585 if (cfg->verbose_level >= 4)
586 printf ("\tADD R%d <- R%d in BB%d\n", var->dreg, sreg, pred->block_num);
587 if (var->dreg != sreg) {
588 MONO_INST_NEW (cfg, move, op_phi_to_move (ins->opcode));
589 if (move->opcode == OP_VMOVE) {
590 g_assert (ins->klass);
591 move->klass = ins->klass;
592 }
593 move->dreg = var->dreg;
594 move->sreg1 = sreg;
595 mono_add_ins_to_end (pred, move);
596 }
597 }
598
599 NULLIFY_INS (ins);
600 }
601 }
602 }
603 }
604
605 if (cfg->verbose_level >= 4) {
606 for (i = 0; i < cfg->num_bblocks; ++i) {
607 MonoBasicBlock *bb = cfg->bblocks [i];
608
609 mono_print_bb (bb, "AFTER REMOVE SSA:");
610 }
611 }
612
613 /*
614 * Removal of SSA form introduces many copies. To avoid this, we tyry to coalesce
615 * the variables if possible. Since the newly introduced SSA variables don't
616 * have overlapping live ranges (because we don't do agressive optimization), we
617 * can coalesce them into the original variable.
618 */
619
620 for (bbindex = 0; bbindex < cfg->num_bblocks; ++bbindex) {
621 MonoBasicBlock *bb = cfg->bblocks [bbindex];
622
623 for (ins = bb->code; ins; ins = ins->next) {
624 const char *spec = INS_INFO (ins->opcode);
625 int num_sregs;
626 int sregs [MONO_MAX_SRC_REGS];
627
628 if (ins->opcode == OP_NOP)
629 continue;
630
631 if (spec [MONO_INST_DEST] != ' ') {
632 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
633
634 if (var) {
635 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
636
637 /*
638 * The third condition avoids coalescing with variables eliminated
639 * during deadce.
640 */
641 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
642 printf ("COALESCE: R%d -> R%d\n", ins->dreg, cfg->varinfo [vmv->reg]->dreg);
643 ins->dreg = cfg->varinfo [vmv->reg]->dreg;
644 }
645 }
646 }
647
648 num_sregs = mono_inst_get_src_registers (ins, sregs);
649 for (i = 0; i < num_sregs; ++i) {
650 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
651
652 if (var) {
653 MonoMethodVar *vmv = MONO_VARINFO (cfg, var->inst_c0);
654
655 if ((vmv->reg != -1) && (vmv->idx != vmv->reg) && (MONO_VARINFO (cfg, vmv->reg)->reg != -1)) {
656 printf ("COALESCE: R%d -> R%d\n", sregs [i], cfg->varinfo [vmv->reg]->dreg);
657 sregs [i] = cfg->varinfo [vmv->reg]->dreg;
658 }
659 }
660 }
661 mono_inst_set_src_registers (ins, sregs);
662 }
663 }
664
665 for (i = 0; i < cfg->num_varinfo; ++i) {
666 MONO_VARINFO (cfg, i)->reg = -1;
667 }
668
669 if (cfg->comp_done & MONO_COMP_REACHABILITY)
670 unlink_unused_bblocks (cfg);
671
672 cfg->comp_done &= ~MONO_COMP_LIVENESS;
673
674 cfg->comp_done &= ~MONO_COMP_SSA;
675 }
676
677 static void
678 mono_ssa_create_def_use (MonoCompile *cfg)
679 {
680 MonoBasicBlock *bb;
681 MonoInst *ins;
682 int i;
683
684 g_assert (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE));
685
686 for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
687 for (ins = bb->code; ins; ins = ins->next) {
688 const char *spec = INS_INFO (ins->opcode);
689 MonoMethodVar *info;
690 int num_sregs;
691 int sregs [MONO_MAX_SRC_REGS];
692
693 if (ins->opcode == OP_NOP)
694 continue;
695
696 /* SREGs */
697 num_sregs = mono_inst_get_src_registers (ins, sregs);
698 for (i = 0; i < num_sregs; ++i) {
699 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
700 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
701 record_use (cfg, var, bb, ins);
702 }
703
704 if (MONO_IS_STORE_MEMBASE (ins)) {
705 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
706 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
707 record_use (cfg, var, bb, ins);
708 }
709
710 if (MONO_IS_PHI (ins)) {
711 for (i = ins->inst_phi_args [0]; i > 0; i--) {
712 g_assert (ins->inst_phi_args [i] != -1);
713 record_use (cfg, get_vreg_to_inst (cfg, ins->inst_phi_args [i]), bb, ins);
714 }
715 }
716
717 /* DREG */
718 if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins)) {
719 MonoInst *var = get_vreg_to_inst (cfg, ins->dreg);
720
721 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
722 info = MONO_VARINFO (cfg, var->inst_c0);
723 info->def = ins;
724 info->def_bb = bb;
725 }
726 }
727 }
728 }
729
730 cfg->comp_done |= MONO_COMP_SSA_DEF_USE;
731 }
732
733 static void
734 mono_ssa_copyprop (MonoCompile *cfg)
735 {
736 int i, index;
737 GList *l;
738
739 g_assert ((cfg->comp_done & MONO_COMP_SSA_DEF_USE));
740
741 for (index = 0; index < cfg->num_varinfo; ++index) {
742 MonoInst *var = cfg->varinfo [index];
743 MonoMethodVar *info = MONO_VARINFO (cfg, index);
744
745 if (info->def && (MONO_IS_MOVE (info->def))) {
746 MonoInst *var2 = get_vreg_to_inst (cfg, info->def->sreg1);
747
748 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))) {
749 /* Rewrite all uses of var to be uses of var2 */
750 int dreg = var->dreg;
751 int sreg1 = var2->dreg;
752
753 l = info->uses;
754 while (l) {
755 MonoVarUsageInfo *u = (MonoVarUsageInfo*)l->data;
756 MonoInst *ins = u->inst;
757 GList *next = l->next;
758 int num_sregs;
759 int sregs [MONO_MAX_SRC_REGS];
760
761 num_sregs = mono_inst_get_src_registers (ins, sregs);
762 for (i = 0; i < num_sregs; ++i) {
763 if (sregs [i] == dreg)
764 break;
765 }
766 if (i < num_sregs) {
767 g_assert (sregs [i] == dreg);
768 sregs [i] = sreg1;
769 mono_inst_set_src_registers (ins, sregs);
770 } else if (MONO_IS_STORE_MEMBASE (ins) && ins->dreg == dreg) {
771 ins->dreg = sreg1;
772 } else if (MONO_IS_PHI (ins)) {
773 for (i = ins->inst_phi_args [0]; i > 0; i--) {
774 int sreg = ins->inst_phi_args [i];
775 if (sreg == var->dreg)
776 break;
777 }
778 g_assert (i > 0);
779 ins->inst_phi_args [i] = sreg1;
780 }
781 else
782 g_assert_not_reached ();
783
784 record_use (cfg, var2, u->bb, ins);
785
786 l = next;
787 }
788
789 info->uses = NULL;
790 }
791 }
792 }
793
794 if (cfg->verbose_level >= 4) {
795 MonoBasicBlock *bb;
796
797 for (bb = cfg->bb_entry; bb; bb = bb->next_bb)
798 mono_print_bb (bb, "AFTER SSA COPYPROP");
799 }
800 }
801
802 static int
803 evaluate_ins (MonoCompile *cfg, MonoInst *ins, MonoInst **res, MonoInst **carray)
804 {
805 MonoInst *args [MONO_MAX_SRC_REGS];
806 int rs [MONO_MAX_SRC_REGS];
807 MonoInst *c0;
808 gboolean const_args = TRUE;
809 const char *spec = INS_INFO (ins->opcode);
810 int num_sregs, i;
811 int sregs [MONO_MAX_SRC_REGS];
812
813 /* Short-circuit this */
814 if (ins->opcode == OP_ICONST) {
815 *res = ins;
816 return 1;
817 }
818
819 if (ins->opcode == OP_NOP)
820 return 2;
821
822 num_sregs = mono_inst_get_src_registers (ins, sregs);
823 for (i = 0; i < MONO_MAX_SRC_REGS; ++i)
824 args [i] = NULL;
825 for (i = 0; i < num_sregs; ++i) {
826 MonoInst *var = get_vreg_to_inst (cfg, sregs [i]);
827
828 rs [i] = 2;
829 args [i] = carray [sregs [i]];
830 if (args [i])
831 rs [i] = 1;
832 else if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
833 rs [i] = MONO_VARINFO (cfg, var->inst_c0)->cpstate;
834 if (rs [i] != 1)
835 const_args = FALSE;
836 }
837
838 c0 = NULL;
839
840 if (num_sregs > 0 && const_args) {
841 g_assert (num_sregs <= 2);
842 if ((spec [MONO_INST_DEST] != ' ') && carray [ins->dreg]) {
843 // Cached value
844 *res = carray [ins->dreg];
845 return 1;
846 }
847 c0 = mono_constant_fold_ins (cfg, ins, args [0], args [1], FALSE);
848 if (c0) {
849 if (G_UNLIKELY (cfg->verbose_level > 1)) {
850 printf ("\t cfold -> ");
851 mono_print_ins (c0);
852 }
853 *res = c0;
854 return 1;
855 }
856 else
857 /* Can't cfold this ins */
858 return 2;
859 }
860
861 if (num_sregs == 0)
862 return 2;
863 for (i = 0; i < num_sregs; ++i) {
864 if (rs [i] == 2)
865 return 2;
866 }
867 return 0;
868 }
869
870 static inline void
871 change_varstate (MonoCompile *cfg, GList **cvars, MonoMethodVar *info, int state, MonoInst *c0, MonoInst **carray)
872 {
873 if (info->cpstate >= state)
874 return;
875
876 info->cpstate = state;
877
878 if (G_UNLIKELY (cfg->verbose_level > 1))
879 printf ("\tState of R%d set to %d\n", cfg->varinfo [info->idx]->dreg, info->cpstate);
880
881 if (state == 1)
882 g_assert (c0);
883
884 carray [cfg->varinfo [info->idx]->dreg] = c0;
885
886 if (!g_list_find (*cvars, info)) {
887 *cvars = g_list_prepend (*cvars, info);
888 }
889 }
890
891 static inline void
892 add_cprop_bb (MonoCompile *cfg, MonoBasicBlock *bb, GList **bblist)
893 {
894 if (G_UNLIKELY (cfg->verbose_level > 1))
895 printf ("\tAdd BB%d to worklist\n", bb->block_num);
896
897 if (!(bb->flags & BB_REACHABLE)) {
898 bb->flags |= BB_REACHABLE;
899 *bblist = g_list_prepend (*bblist, bb);
900 }
901 }
902
903 static void
904 visit_inst (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, GList **cvars, GList **bblist, MonoInst **carray)
905 {
906 const char *spec = INS_INFO (ins->opcode);
907
908 if (ins->opcode == OP_NOP)
909 return;
910
911 if (cfg->verbose_level > 1)
912 mono_print_ins (ins);
913
914 /* FIXME: Support longs/floats */
915 /* FIXME: Work on vregs as well */
916
917 if (MONO_IS_PHI (ins)) {
918 MonoMethodVar *info = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, ins->dreg)->inst_c0);
919 MonoInst *c0 = NULL;
920 int j;
921
922 for (j = 1; j <= ins->inst_phi_args [0]; j++) {
923 MonoInst *var = get_vreg_to_inst (cfg, ins->inst_phi_args [j]);
924 MonoMethodVar *mv = MONO_VARINFO (cfg, var->inst_c0);
925 MonoInst *src = mv->def;
926
927 if (mv->def_bb && !(mv->def_bb->flags & BB_REACHABLE))
928 continue;
929
930 if (!mv->def || !src || mv->cpstate == 2) {
931 change_varstate (cfg, cvars, info, 2, NULL, carray);
932 break;
933 }
934
935 if (mv->cpstate == 0)
936 continue;
937
938 g_assert (carray [var->dreg]);
939
940 if (!c0)
941 c0 = carray [var->dreg];
942
943 /* FIXME: */
944 if (c0->opcode != OP_ICONST) {
945 change_varstate (cfg, cvars, info, 2, NULL, carray);
946 break;
947 }
948
949 if (carray [var->dreg]->inst_c0 != c0->inst_c0) {
950 change_varstate (cfg, cvars, info, 2, NULL, carray);
951 break;
952 }
953 }
954
955 if (c0 && info->cpstate < 1) {
956 change_varstate (cfg, cvars, info, 1, c0, carray);
957
958 g_assert (c0->opcode == OP_ICONST);
959 }
960 }
961 else if (!MONO_IS_STORE_MEMBASE (ins) && ((spec [MONO_INST_SRC1] != ' ') || (spec [MONO_INST_SRC2] != ' ') || (spec [MONO_INST_DEST] != ' '))) {
962 MonoInst *var, *c0;
963 int state;
964
965 if (spec [MONO_INST_DEST] != ' ')
966 var = get_vreg_to_inst (cfg, ins->dreg);
967 else
968 var = NULL;
969
970 c0 = NULL;
971 state = evaluate_ins (cfg, ins, &c0, carray);
972
973 if (var && !(var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT))) {
974 MonoMethodVar *info = MONO_VARINFO (cfg, var->inst_c0);
975
976 if (info->cpstate < 2) {
977 if (state == 1)
978 change_varstate (cfg, cvars, info, 1, c0, carray);
979 else if (state == 2)
980 change_varstate (cfg, cvars, info, 2, NULL, carray);
981 }
982 }
983 else if (!var && (ins->dreg != -1)) {
984 /*
985 * We don't record def-use information for local vregs since it would be
986 * expensive. Instead, we depend on the fact that all uses of the vreg are in
987 * the same bblock, so they will be examined after the definition.
988 * FIXME: This isn't true if the ins is visited through an SSA edge.
989 */
990 if (c0) {
991 carray [ins->dreg] = c0;
992 } else {
993 if (carray [ins->dreg]) {
994 /*
995 * The state of the vreg changed from constant to non-constant
996 * -> need to rescan the whole bblock.
997 */
998 carray [ins->dreg] = NULL;
999 /* FIXME: Speed this up */
1000
1001 if (!g_list_find (*bblist, bb))
1002 *bblist = g_list_prepend (*bblist, bb);
1003 }
1004 }
1005 }
1006
1007 if (MONO_IS_JUMP_TABLE (ins)) {
1008 int i;
1009 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1010
1011 if (!ins->next || ins->next->opcode != OP_PADD) {
1012 /* The PADD was optimized away */
1013 /* FIXME: handle this as well */
1014 for (i = 0; i < table->table_size; i++)
1015 if (table->table [i])
1016 add_cprop_bb (cfg, table->table [i], bblist);
1017 return;
1018 }
1019
1020 g_assert (ins->next->opcode == OP_PADD);
1021 g_assert (ins->next->sreg1 == ins->dreg);
1022
1023 if (carray [ins->next->sreg2]) {
1024 #if SIZEOF_REGISTER == 8
1025 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1026 #else
1027 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1028 #endif
1029 if ((idx < 0) || (idx >= table->table_size))
1030 /* Out-of-range, no branch is executed */
1031 return;
1032 else
1033 if (table->table [idx])
1034 add_cprop_bb (cfg, table->table [idx], bblist);
1035 }
1036 else {
1037 for (i = 0; i < table->table_size; i++)
1038 if (table->table [i])
1039 add_cprop_bb (cfg, table->table [i], bblist);
1040 }
1041 }
1042
1043 if (ins->opcode == OP_SWITCH) {
1044 int i;
1045 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)ins->inst_p0;
1046
1047 for (i = 0; i < table->table_size; i++)
1048 if (table->table [i])
1049 add_cprop_bb (cfg, table->table [i], bblist);
1050 }
1051
1052 /* Handle COMPARE+BRCOND pairs */
1053 if (ins->next && MONO_IS_COND_BRANCH_OP (ins->next)) {
1054 if (c0) {
1055 g_assert (c0->opcode == OP_ICONST);
1056
1057 if (c0->inst_c0)
1058 ins->next->flags |= MONO_INST_CFOLD_TAKEN;
1059 else
1060 ins->next->flags |= MONO_INST_CFOLD_NOT_TAKEN;
1061 }
1062 else {
1063 ins->next->flags &= ~(MONO_INST_CFOLD_TAKEN | MONO_INST_CFOLD_NOT_TAKEN);
1064 }
1065
1066 visit_inst (cfg, bb, ins->next, cvars, bblist, carray);
1067 }
1068 } else if (ins->opcode == OP_BR) {
1069 add_cprop_bb (cfg, ins->inst_target_bb, bblist);
1070 } else if (MONO_IS_COND_BRANCH_OP (ins)) {
1071 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1072 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1073 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1074 if (ins->inst_false_bb)
1075 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1076 } else {
1077 add_cprop_bb (cfg, ins->inst_true_bb, bblist);
1078 if (ins->inst_false_bb)
1079 add_cprop_bb (cfg, ins->inst_false_bb, bblist);
1080 }
1081 }
1082 }
1083
1084 /**
1085 * fold_ins:
1086 *
1087 * Replace INS with its constant value, if it exists
1088 */
1089 static void
1090 fold_ins (MonoCompile *cfg, MonoBasicBlock *bb, MonoInst *ins, MonoInst **carray)
1091 {
1092 const char *spec = INS_INFO (ins->opcode);
1093 int opcode2;
1094 int num_sregs = mono_inst_get_num_src_registers (ins);
1095
1096 if ((ins->opcode != OP_NOP) && (ins->dreg != -1) && !MONO_IS_STORE_MEMBASE (ins)) {
1097 if (carray [ins->dreg] && (spec [MONO_INST_DEST] == 'i') && (ins->dreg >= MONO_MAX_IREGS)) {
1098 /* Perform constant folding */
1099 /* FIXME: */
1100 g_assert (carray [ins->dreg]->opcode == OP_ICONST);
1101 ins->opcode = OP_ICONST;
1102 ins->inst_c0 = carray [ins->dreg]->inst_c0;
1103 MONO_INST_NULLIFY_SREGS (ins);
1104 } else if (num_sregs == 2 && carray [ins->sreg2]) {
1105 /* Perform op->op_imm conversion */
1106 opcode2 = mono_op_to_op_imm (ins->opcode);
1107 if (opcode2 != -1) {
1108 ins->opcode = opcode2;
1109 ins->inst_imm = carray [ins->sreg2]->inst_c0;
1110 ins->sreg2 = -1;
1111
1112 if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
1113 ((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
1114 }
1115 } else {
1116 /* FIXME: Handle 3 op insns */
1117 }
1118
1119 if (MONO_IS_JUMP_TABLE (ins)) {
1120 int i;
1121 MonoJumpInfoBBTable *table = (MonoJumpInfoBBTable *)MONO_JUMP_TABLE_FROM_INS (ins);
1122
1123 if (!ins->next || ins->next->opcode != OP_PADD) {
1124 /* The PADD was optimized away */
1125 /* FIXME: handle this as well */
1126 return;
1127 }
1128
1129 g_assert (ins->next->opcode == OP_PADD);
1130 g_assert (ins->next->sreg1 == ins->dreg);
1131 g_assert (ins->next->next->opcode == OP_LOAD_MEMBASE);
1132
1133 if (carray [ins->next->sreg2]) {
1134 /* Convert to a simple branch */
1135 #if SIZEOF_REGISTER == 8
1136 int idx = carray [ins->next->sreg2]->inst_c0 >> 3;
1137 #else
1138 int idx = carray [ins->next->sreg2]->inst_c0 >> 2;
1139 #endif
1140
1141 if (!((idx >= 0) && (idx < table->table_size))) {
1142 /* Out of range, eliminate the whole switch */
1143 for (i = 0; i < table->table_size; ++i) {
1144 remove_bb_from_phis (cfg, bb, table->table [i]);
1145 mono_unlink_bblock (cfg, bb, table->table [i]);
1146 }
1147
1148 NULLIFY_INS (ins);
1149 NULLIFY_INS (ins->next);
1150 NULLIFY_INS (ins->next->next);
1151 if (ins->next->next->next)
1152 NULLIFY_INS (ins->next->next->next);
1153
1154 return;
1155 }
1156
1157 if (!ins->next->next->next || ins->next->next->next->opcode != OP_BR_REG) {
1158 /* A one-way switch which got optimized away */
1159 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1160 printf ("\tNo cfold on ");
1161 mono_print_ins (ins);
1162 }
1163 return;
1164 }
1165
1166 if (G_UNLIKELY (cfg->verbose_level > 1)) {
1167 printf ("\tcfold on ");
1168 mono_print_ins (ins);
1169 }
1170
1171 /* Unlink target bblocks */
1172 for (i = 0; i < table->table_size; ++i) {
1173 if (table->table [i] != table->table [idx]) {
1174 remove_bb_from_phis (cfg, bb, table->table [i]);
1175 mono_unlink_bblock (cfg, bb, table->table [i]);
1176 }
1177 }
1178
1179 /* Change the OP_BR_REG to a simple branch */
1180 ins->next->next->next->opcode = OP_BR;
1181 ins->next->next->next->inst_target_bb = table->table [idx];
1182 ins->next->next->next->sreg1 = -1;
1183
1184 /* Nullify the other instructions */
1185 NULLIFY_INS (ins);
1186 NULLIFY_INS (ins->next);
1187 NULLIFY_INS (ins->next->next);
1188 }
1189 }
1190 }
1191 else if (MONO_IS_COND_BRANCH_OP (ins)) {
1192 if (ins->flags & MONO_INST_CFOLD_TAKEN) {
1193 remove_bb_from_phis (cfg, bb, ins->inst_false_bb);
1194 mono_unlink_bblock (cfg, bb, ins->inst_false_bb);
1195 ins->opcode = OP_BR;
1196 ins->inst_target_bb = ins->inst_true_bb;
1197 } else if (ins->flags & MONO_INST_CFOLD_NOT_TAKEN) {
1198 remove_bb_from_phis (cfg, bb, ins->inst_true_bb);
1199 mono_unlink_bblock (cfg, bb, ins->inst_true_bb);
1200 ins->opcode = OP_BR;
1201 ins->inst_target_bb = ins->inst_false_bb;
1202 }
1203 }
1204 }
1205
1206 void
1207 mono_ssa_cprop (MonoCompile *cfg)
1208 {
1209 MonoInst **carray;
1210 MonoBasicBlock *bb;
1211 GList *bblock_list, *cvars;
1212 GList *tmp;
1213 int i;
1214 //printf ("SIMPLE OPTS BB%d %s\n", bb->block_num, mono_method_full_name (cfg->method, TRUE));
1215
1216 carray = g_new0 (MonoInst*, cfg->next_vreg);
1217
1218 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1219 mono_ssa_create_def_use (cfg);
1220
1221 bblock_list = g_list_prepend (NULL, cfg->bb_entry);
1222 cfg->bb_entry->flags |= BB_REACHABLE;
1223
1224 memset (carray, 0, sizeof (MonoInst *) * cfg->num_varinfo);
1225
1226 for (i = 0; i < cfg->num_varinfo; i++) {
1227 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1228 if (!info->def)
1229 info->cpstate = 2;
1230 }
1231
1232 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1233 /*
1234 * FIXME: This should be bb->flags & BB_FLAG_EXCEPTION_HANDLER, but
1235 * that would still allow unreachable try's to be removed.
1236 */
1237 if (bb->region)
1238 add_cprop_bb (cfg, bb, &bblock_list);
1239 }
1240
1241 cvars = NULL;
1242
1243 while (bblock_list) {
1244 MonoInst *inst;
1245
1246 bb = (MonoBasicBlock *)bblock_list->data;
1247
1248 bblock_list = g_list_delete_link (bblock_list, bblock_list);
1249
1250 g_assert (bb->flags & BB_REACHABLE);
1251
1252 /*
1253 * Some bblocks are linked to 2 others even through they fall through to the
1254 * next bblock.
1255 */
1256 if (!(bb->last_ins && MONO_IS_BRANCH_OP (bb->last_ins))) {
1257 for (i = 0; i < bb->out_count; ++i)
1258 add_cprop_bb (cfg, bb->out_bb [i], &bblock_list);
1259 }
1260
1261 if (cfg->verbose_level > 1)
1262 printf ("\nSSA CONSPROP BB%d:\n", bb->block_num);
1263
1264 for (inst = bb->code; inst; inst = inst->next) {
1265 visit_inst (cfg, bb, inst, &cvars, &bblock_list, carray);
1266 }
1267
1268 while (cvars) {
1269 MonoMethodVar *info = (MonoMethodVar *)cvars->data;
1270 cvars = g_list_delete_link (cvars, cvars);
1271
1272 for (tmp = info->uses; tmp; tmp = tmp->next) {
1273 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1274 if (!(ui->bb->flags & BB_REACHABLE))
1275 continue;
1276 visit_inst (cfg, ui->bb, ui->inst, &cvars, &bblock_list, carray);
1277 }
1278 }
1279 }
1280
1281 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1282 MonoInst *inst;
1283 for (inst = bb->code; inst; inst = inst->next) {
1284 fold_ins (cfg, bb, inst, carray);
1285 }
1286 }
1287
1288 g_free (carray);
1289
1290 cfg->comp_done |= MONO_COMP_REACHABILITY;
1291
1292 /* fixme: we should update usage infos during cprop, instead of computing it again */
1293 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1294 for (i = 0; i < cfg->num_varinfo; i++) {
1295 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1296 info->def = NULL;
1297 info->uses = NULL;
1298 }
1299 }
1300
1301 static inline void
1302 add_to_dce_worklist (MonoCompile *cfg, MonoMethodVar *var, MonoMethodVar *use, GList **wl)
1303 {
1304 GList *tmp;
1305
1306 *wl = g_list_prepend_mempool (cfg->mempool, *wl, use);
1307
1308 for (tmp = use->uses; tmp; tmp = tmp->next) {
1309 MonoVarUsageInfo *ui = (MonoVarUsageInfo *)tmp->data;
1310 if (ui->inst == var->def) {
1311 /* from the mempool */
1312 use->uses = g_list_remove_link (use->uses, tmp);
1313 break;
1314 }
1315 }
1316 }
1317
1318 void
1319 mono_ssa_deadce (MonoCompile *cfg)
1320 {
1321 int i;
1322 GList *work_list;
1323
1324 g_assert (cfg->comp_done & MONO_COMP_SSA);
1325
1326 //printf ("DEADCE %s\n", mono_method_full_name (cfg->method, TRUE));
1327
1328 if (!(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1329 mono_ssa_create_def_use (cfg);
1330
1331 mono_ssa_copyprop (cfg);
1332
1333 work_list = NULL;
1334 for (i = 0; i < cfg->num_varinfo; i++) {
1335 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1336 work_list = g_list_prepend_mempool (cfg->mempool, work_list, info);
1337 }
1338
1339 while (work_list) {
1340 MonoMethodVar *info = (MonoMethodVar *)work_list->data;
1341 work_list = g_list_remove_link (work_list, work_list);
1342
1343 /*
1344 * The second part of the condition happens often when PHI nodes have their dreg
1345 * as one of their arguments due to the fact that we use the original vars.
1346 */
1347 if (info->def && (!info->uses || ((info->uses->next == NULL) && (((MonoVarUsageInfo*)info->uses->data)->inst == info->def)))) {
1348 MonoInst *def = info->def;
1349
1350 /* Eliminating FMOVE could screw up the fp stack */
1351 if (MONO_IS_MOVE (def) && (!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE))) {
1352 MonoInst *src_var = get_vreg_to_inst (cfg, def->sreg1);
1353 if (src_var && !(src_var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1354 add_to_dce_worklist (cfg, info, MONO_VARINFO (cfg, src_var->inst_c0), &work_list);
1355 NULLIFY_INS (def);
1356 info->reg = -1;
1357 } else if ((def->opcode == OP_ICONST) || (def->opcode == OP_I8CONST) || MONO_IS_ZERO (def)) {
1358 NULLIFY_INS (def);
1359 info->reg = -1;
1360 } else if (MONO_IS_PHI (def)) {
1361 int j;
1362 for (j = def->inst_phi_args [0]; j > 0; j--) {
1363 MonoMethodVar *u = MONO_VARINFO (cfg, get_vreg_to_inst (cfg, def->inst_phi_args [j])->inst_c0);
1364 add_to_dce_worklist (cfg, info, u, &work_list);
1365 }
1366 NULLIFY_INS (def);
1367 info->reg = -1;
1368 }
1369 else if (def->opcode == OP_NOP) {
1370 }
1371 //else
1372 //mono_print_ins (def);
1373 }
1374
1375 }
1376 }
1377
1378 #if 0
1379 void
1380 mono_ssa_strength_reduction (MonoCompile *cfg)
1381 {
1382 MonoBasicBlock *bb;
1383 int i;
1384
1385 g_assert (cfg->comp_done & MONO_COMP_SSA);
1386 g_assert (cfg->comp_done & MONO_COMP_LOOPS);
1387 g_assert (cfg->comp_done & MONO_COMP_SSA_DEF_USE);
1388
1389 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1390 GList *lp = bb->loop_blocks;
1391
1392 if (lp) {
1393 MonoBasicBlock *h = (MonoBasicBlock *)lp->data;
1394
1395 /* we only consider loops with 2 in bblocks */
1396 if (!h->in_count == 2)
1397 continue;
1398
1399 for (i = 0; i < cfg->num_varinfo; i++) {
1400 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1401
1402 if (info->def && info->def->ssa_op == MONO_SSA_STORE &&
1403 info->def->inst_i0->opcode == OP_LOCAL && g_list_find (lp, info->def_bb)) {
1404 MonoInst *v = info->def->inst_i1;
1405
1406
1407 printf ("FOUND %d in %s\n", info->idx, mono_method_full_name (cfg->method, TRUE));
1408 }
1409 }
1410 }
1411 }
1412 }
1413 #endif
1414
1415 void
1416 mono_ssa_loop_invariant_code_motion (MonoCompile *cfg)
1417 {
1418 MonoBasicBlock *bb, *h, *idom;
1419 MonoInst *ins, *n, *tins;
1420 int i;
1421
1422 g_assert (cfg->comp_done & MONO_COMP_SSA);
1423 if (!(cfg->comp_done & MONO_COMP_LOOPS) || !(cfg->comp_done & MONO_COMP_SSA_DEF_USE))
1424 return;
1425
1426 for (bb = cfg->bb_entry->next_bb; bb; bb = bb->next_bb) {
1427 GList *lp = bb->loop_blocks;
1428
1429 if (!lp)
1430 continue;
1431 h = (MonoBasicBlock *)lp->data;
1432 if (bb != h)
1433 continue;
1434 MONO_BB_FOR_EACH_INS_SAFE (bb, n, ins) {
1435 /*
1436 * Try to move instructions out of loop headers into the preceeding bblock.
1437 */
1438 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS || ins->opcode == OP_AOTCONST || ins->opcode == OP_GENERIC_CLASS_INIT) {
1439 gboolean skip;
1440 int sreg;
1441
1442 idom = h->idom;
1443 /*
1444 * h->nesting is needed to work around:
1445 * http://llvm.org/bugs/show_bug.cgi?id=17868
1446 */
1447 if (!(idom && idom->last_ins && idom->last_ins->opcode == OP_BR && idom->last_ins->inst_target_bb == h && h->nesting == 1)) {
1448 continue;
1449 }
1450
1451 /*
1452 * Make sure there are no instructions with side effects before ins.
1453 */
1454 skip = FALSE;
1455 MONO_BB_FOR_EACH_INS (bb, tins) {
1456 if (tins == ins)
1457 break;
1458 if (!MONO_INS_HAS_NO_SIDE_EFFECT (tins)) {
1459 skip = TRUE;
1460 break;
1461 }
1462 }
1463 if (skip) {
1464 /*
1465 printf ("%s\n", mono_method_full_name (cfg->method, TRUE));
1466 mono_print_ins (tins);
1467 */
1468 continue;
1469 }
1470
1471 /* Make sure we don't move the instruction before the def of its sreg */
1472 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN || ins->opcode == OP_CHECK_THIS)
1473 sreg = ins->sreg1;
1474 else
1475 sreg = -1;
1476 if (sreg != -1) {
1477 MonoInst *tins, *var;
1478
1479 skip = FALSE;
1480 for (tins = ins->prev; tins; tins = tins->prev) {
1481 const char *spec = INS_INFO (tins->opcode);
1482
1483 if (tins->opcode == OP_MOVE && tins->dreg == sreg) {
1484 sreg = tins->sreg1;
1485 } if (spec [MONO_INST_DEST] != ' ' && tins->dreg == sreg) {
1486 skip = TRUE;
1487 break;
1488 }
1489 }
1490 if (skip)
1491 continue;
1492 var = get_vreg_to_inst (cfg, sreg);
1493 if (var && (var->flags & (MONO_INST_VOLATILE|MONO_INST_INDIRECT)))
1494 continue;
1495 ins->sreg1 = sreg;
1496 }
1497
1498 if (cfg->verbose_level > 1) {
1499 printf ("licm in BB%d on ", bb->block_num);
1500 mono_print_ins (ins);
1501 }
1502 //{ static int count = 0; count ++; printf ("%d\n", count); }
1503 MONO_REMOVE_INS (bb, ins);
1504 mono_bblock_insert_before_ins (idom, idom->last_ins, ins);
1505 if (ins->opcode == OP_LDLEN || ins->opcode == OP_STRLEN)
1506 idom->has_array_access = TRUE;
1507 }
1508 }
1509 }
1510
1511 cfg->comp_done &= ~MONO_COMP_SSA_DEF_USE;
1512 for (i = 0; i < cfg->num_varinfo; i++) {
1513 MonoMethodVar *info = MONO_VARINFO (cfg, i);
1514 info->def = NULL;
1515 info->uses = NULL;
1516 }
1517 }
1518
1519 #else /* !DISABLE_JIT */
1520
1521 MONO_EMPTY_SOURCE_FILE (ssa);
1522
1523 #endif /* !DISABLE_JIT */
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