Mercurial > hg > truffle
annotate src/share/vm/c1/c1_ValueMap.cpp @ 14517:3812c088b945
Merge
author | lana |
---|---|
date | Thu, 06 Mar 2014 10:37:26 -0800 |
parents | de6a9e811145 |
children | 4ca6dc0799b6 |
rev | line source |
---|---|
0 | 1 /* |
14223
de6a9e811145
8029233: Update copyright year to match last edit in jdk8 hotspot repository for 2013
mikael
parents:
9081
diff
changeset
|
2 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
1552
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
0
diff
changeset
|
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
0
diff
changeset
|
20 * or visit www.oracle.com if you need additional information or have any |
c18cbe5936b8
6941466: Oracle rebranding changes for Hotspot repositories
trims
parents:
0
diff
changeset
|
21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "c1/c1_Canonicalizer.hpp" | |
27 #include "c1/c1_IR.hpp" | |
28 #include "c1/c1_ValueMap.hpp" | |
8860 | 29 #include "c1/c1_ValueStack.hpp" |
1972 | 30 #include "utilities/bitMap.inline.hpp" |
0 | 31 |
32 #ifndef PRODUCT | |
33 | |
34 int ValueMap::_number_of_finds = 0; | |
35 int ValueMap::_number_of_hits = 0; | |
36 int ValueMap::_number_of_kills = 0; | |
37 | |
38 #define TRACE_VALUE_NUMBERING(code) if (PrintValueNumbering) { code; } | |
39 | |
40 #else | |
41 | |
42 #define TRACE_VALUE_NUMBERING(code) | |
43 | |
44 #endif | |
45 | |
46 | |
47 ValueMap::ValueMap() | |
48 : _nesting(0) | |
49 , _entries(ValueMapInitialSize, NULL) | |
50 , _killed_values() | |
51 , _entry_count(0) | |
52 { | |
53 NOT_PRODUCT(reset_statistics()); | |
54 } | |
55 | |
56 | |
57 ValueMap::ValueMap(ValueMap* old) | |
58 : _nesting(old->_nesting + 1) | |
59 , _entries(old->_entries.length()) | |
60 , _killed_values() | |
61 , _entry_count(old->_entry_count) | |
62 { | |
63 for (int i = size() - 1; i >= 0; i--) { | |
64 _entries.at_put(i, old->entry_at(i)); | |
65 } | |
66 _killed_values.set_from(&old->_killed_values); | |
67 } | |
68 | |
69 | |
70 void ValueMap::increase_table_size() { | |
71 int old_size = size(); | |
72 int new_size = old_size * 2 + 1; | |
73 | |
74 ValueMapEntryList worklist(8); | |
75 ValueMapEntryArray new_entries(new_size, NULL); | |
76 int new_entry_count = 0; | |
77 | |
78 TRACE_VALUE_NUMBERING(tty->print_cr("increasing table size from %d to %d", old_size, new_size)); | |
79 | |
80 for (int i = old_size - 1; i >= 0; i--) { | |
81 ValueMapEntry* entry; | |
82 for (entry = entry_at(i); entry != NULL; entry = entry->next()) { | |
83 if (!is_killed(entry->value())) { | |
84 worklist.push(entry); | |
85 } | |
86 } | |
87 | |
88 while (!worklist.is_empty()) { | |
89 entry = worklist.pop(); | |
90 int new_index = entry_index(entry->hash(), new_size); | |
91 | |
92 if (entry->nesting() != nesting() && new_entries.at(new_index) != entry->next()) { | |
93 // changing entries with a lower nesting than the current nesting of the table | |
94 // is not allowed because then the same entry is contained in multiple value maps. | |
95 // clone entry when next-pointer must be changed | |
96 entry = new ValueMapEntry(entry->hash(), entry->value(), entry->nesting(), NULL); | |
97 } | |
98 entry->set_next(new_entries.at(new_index)); | |
99 new_entries.at_put(new_index, entry); | |
100 new_entry_count++; | |
101 } | |
102 } | |
103 | |
104 _entries = new_entries; | |
105 _entry_count = new_entry_count; | |
106 } | |
107 | |
108 | |
109 Value ValueMap::find_insert(Value x) { | |
110 const intx hash = x->hash(); | |
111 if (hash != 0) { | |
112 // 0 hash means: exclude from value numbering | |
113 NOT_PRODUCT(_number_of_finds++); | |
114 | |
115 for (ValueMapEntry* entry = entry_at(entry_index(hash, size())); entry != NULL; entry = entry->next()) { | |
116 if (entry->hash() == hash) { | |
117 Value f = entry->value(); | |
118 | |
119 if (!is_killed(f) && f->is_equal(x)) { | |
120 NOT_PRODUCT(_number_of_hits++); | |
121 TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: %s %c%d equal to %c%d (size %d, entries %d, nesting-diff %d)", x->name(), x->type()->tchar(), x->id(), f->type()->tchar(), f->id(), size(), entry_count(), nesting() - entry->nesting())); | |
122 | |
123 if (entry->nesting() != nesting() && f->as_Constant() == NULL) { | |
124 // non-constant values of of another block must be pinned, | |
125 // otherwise it is possible that they are not evaluated | |
126 f->pin(Instruction::PinGlobalValueNumbering); | |
127 } | |
4871
f067b4e0e04b
7090976: Eclipse/CDT causes a JVM crash while indexing C++ code
roland
parents:
1972
diff
changeset
|
128 assert(x->type()->tag() == f->type()->tag(), "should have same type"); |
0 | 129 |
130 return f; | |
131 | |
132 } | |
133 } | |
134 } | |
135 | |
136 // x not found, so insert it | |
137 if (entry_count() >= size_threshold()) { | |
138 increase_table_size(); | |
139 } | |
140 int idx = entry_index(hash, size()); | |
141 _entries.at_put(idx, new ValueMapEntry(hash, x, nesting(), entry_at(idx))); | |
142 _entry_count++; | |
143 | |
144 TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: insert %s %c%d (size %d, entries %d, nesting %d)", x->name(), x->type()->tchar(), x->id(), size(), entry_count(), nesting())); | |
145 } | |
146 | |
147 return x; | |
148 } | |
149 | |
150 | |
151 #define GENERIC_KILL_VALUE(must_kill_implementation) \ | |
152 NOT_PRODUCT(_number_of_kills++); \ | |
153 \ | |
154 for (int i = size() - 1; i >= 0; i--) { \ | |
155 ValueMapEntry* prev_entry = NULL; \ | |
156 for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { \ | |
157 Value value = entry->value(); \ | |
158 \ | |
159 must_kill_implementation(must_kill, entry, value) \ | |
160 \ | |
161 if (must_kill) { \ | |
162 kill_value(value); \ | |
163 \ | |
164 if (prev_entry == NULL) { \ | |
165 _entries.at_put(i, entry->next()); \ | |
166 _entry_count--; \ | |
167 } else if (prev_entry->nesting() == nesting()) { \ | |
168 prev_entry->set_next(entry->next()); \ | |
169 _entry_count--; \ | |
170 } else { \ | |
171 prev_entry = entry; \ | |
172 } \ | |
173 \ | |
174 TRACE_VALUE_NUMBERING(tty->print_cr("Value Numbering: killed %s %c%d (size %d, entries %d, nesting-diff %d)", value->name(), value->type()->tchar(), value->id(), size(), entry_count(), nesting() - entry->nesting())); \ | |
175 } else { \ | |
176 prev_entry = entry; \ | |
177 } \ | |
178 } \ | |
179 } \ | |
180 | |
181 #define MUST_KILL_MEMORY(must_kill, entry, value) \ | |
182 bool must_kill = value->as_LoadField() != NULL || value->as_LoadIndexed() != NULL; | |
183 | |
184 #define MUST_KILL_ARRAY(must_kill, entry, value) \ | |
185 bool must_kill = value->as_LoadIndexed() != NULL \ | |
186 && value->type()->tag() == type->tag(); | |
187 | |
188 #define MUST_KILL_FIELD(must_kill, entry, value) \ | |
189 /* ciField's are not unique; must compare their contents */ \ | |
190 LoadField* lf = value->as_LoadField(); \ | |
191 bool must_kill = lf != NULL \ | |
192 && lf->field()->holder() == field->holder() \ | |
6618
0bfcb7a3e12d
7171824: assert(_offset >= 1) failed: illegal call to offset()
roland
parents:
4871
diff
changeset
|
193 && (all_offsets || lf->field()->offset() == field->offset()); |
0 | 194 |
195 | |
196 void ValueMap::kill_memory() { | |
197 GENERIC_KILL_VALUE(MUST_KILL_MEMORY); | |
198 } | |
199 | |
200 void ValueMap::kill_array(ValueType* type) { | |
201 GENERIC_KILL_VALUE(MUST_KILL_ARRAY); | |
202 } | |
203 | |
6618
0bfcb7a3e12d
7171824: assert(_offset >= 1) failed: illegal call to offset()
roland
parents:
4871
diff
changeset
|
204 void ValueMap::kill_field(ciField* field, bool all_offsets) { |
0 | 205 GENERIC_KILL_VALUE(MUST_KILL_FIELD); |
206 } | |
207 | |
208 void ValueMap::kill_map(ValueMap* map) { | |
209 assert(is_global_value_numbering(), "only for global value numbering"); | |
210 _killed_values.set_union(&map->_killed_values); | |
211 } | |
212 | |
213 void ValueMap::kill_all() { | |
214 assert(is_local_value_numbering(), "only for local value numbering"); | |
215 for (int i = size() - 1; i >= 0; i--) { | |
216 _entries.at_put(i, NULL); | |
217 } | |
218 _entry_count = 0; | |
219 } | |
220 | |
221 | |
222 #ifndef PRODUCT | |
223 | |
224 void ValueMap::print() { | |
225 tty->print_cr("(size %d, entries %d, nesting %d)", size(), entry_count(), nesting()); | |
226 | |
227 int entries = 0; | |
228 for (int i = 0; i < size(); i++) { | |
229 if (entry_at(i) != NULL) { | |
230 tty->print(" %2d: ", i); | |
231 for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { | |
232 Value value = entry->value(); | |
233 tty->print("%s %c%d (%s%d) -> ", value->name(), value->type()->tchar(), value->id(), is_killed(value) ? "x" : "", entry->nesting()); | |
234 entries++; | |
235 } | |
236 tty->print_cr("NULL"); | |
237 } | |
238 } | |
239 | |
240 _killed_values.print(); | |
241 assert(entry_count() == entries, "entry_count incorrect"); | |
242 } | |
243 | |
244 void ValueMap::reset_statistics() { | |
245 _number_of_finds = 0; | |
246 _number_of_hits = 0; | |
247 _number_of_kills = 0; | |
248 } | |
249 | |
250 void ValueMap::print_statistics() { | |
251 float hit_rate = 0; | |
252 if (_number_of_finds != 0) { | |
253 hit_rate = (float)_number_of_hits / _number_of_finds; | |
254 } | |
255 | |
256 tty->print_cr("finds:%3d hits:%3d kills:%3d hit rate: %1.4f", _number_of_finds, _number_of_hits, _number_of_kills, hit_rate); | |
257 } | |
258 | |
259 #endif | |
260 | |
261 | |
262 | |
263 class ShortLoopOptimizer : public ValueNumberingVisitor { | |
264 private: | |
265 GlobalValueNumbering* _gvn; | |
266 BlockList _loop_blocks; | |
267 bool _too_complicated_loop; | |
8860 | 268 bool _has_field_store[T_ARRAY + 1]; |
269 bool _has_indexed_store[T_ARRAY + 1]; | |
0 | 270 |
271 // simplified access to methods of GlobalValueNumbering | |
272 ValueMap* current_map() { return _gvn->current_map(); } | |
273 ValueMap* value_map_of(BlockBegin* block) { return _gvn->value_map_of(block); } | |
274 | |
275 // implementation for abstract methods of ValueNumberingVisitor | |
6618
0bfcb7a3e12d
7171824: assert(_offset >= 1) failed: illegal call to offset()
roland
parents:
4871
diff
changeset
|
276 void kill_memory() { _too_complicated_loop = true; } |
8860 | 277 void kill_field(ciField* field, bool all_offsets) { |
278 current_map()->kill_field(field, all_offsets); | |
279 assert(field->type()->basic_type() >= 0 && field->type()->basic_type() <= T_ARRAY, "Invalid type"); | |
280 _has_field_store[field->type()->basic_type()] = true; | |
281 } | |
282 void kill_array(ValueType* type) { | |
283 current_map()->kill_array(type); | |
284 BasicType basic_type = as_BasicType(type); assert(basic_type >= 0 && basic_type <= T_ARRAY, "Invalid type"); | |
285 _has_indexed_store[basic_type] = true; | |
286 } | |
0 | 287 |
288 public: | |
289 ShortLoopOptimizer(GlobalValueNumbering* gvn) | |
290 : _gvn(gvn) | |
291 , _loop_blocks(ValueMapMaxLoopSize) | |
292 , _too_complicated_loop(false) | |
293 { | |
8860 | 294 for (int i=0; i<= T_ARRAY; i++){ |
295 _has_field_store[i] = false; | |
296 _has_indexed_store[i] = false; | |
297 } | |
298 } | |
299 | |
300 bool has_field_store(BasicType type) { | |
301 assert(type >= 0 && type <= T_ARRAY, "Invalid type"); | |
302 return _has_field_store[type]; | |
303 } | |
304 | |
305 bool has_indexed_store(BasicType type) { | |
306 assert(type >= 0 && type <= T_ARRAY, "Invalid type"); | |
307 return _has_indexed_store[type]; | |
0 | 308 } |
309 | |
310 bool process(BlockBegin* loop_header); | |
311 }; | |
312 | |
8860 | 313 class LoopInvariantCodeMotion : public StackObj { |
314 private: | |
315 GlobalValueNumbering* _gvn; | |
316 ShortLoopOptimizer* _short_loop_optimizer; | |
317 Instruction* _insertion_point; | |
318 ValueStack * _state; | |
9081
84ab5667f290
8011706: specjvm2008 test xml.transform gets array bound exception with c1
roland
parents:
8860
diff
changeset
|
319 bool _insert_is_pred; |
8860 | 320 |
321 void set_invariant(Value v) const { _gvn->set_processed(v); } | |
322 bool is_invariant(Value v) const { return _gvn->is_processed(v); } | |
323 | |
324 void process_block(BlockBegin* block); | |
325 | |
326 public: | |
327 LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks); | |
328 }; | |
329 | |
330 LoopInvariantCodeMotion::LoopInvariantCodeMotion(ShortLoopOptimizer *slo, GlobalValueNumbering* gvn, BlockBegin* loop_header, BlockList* loop_blocks) | |
331 : _gvn(gvn), _short_loop_optimizer(slo) { | |
332 | |
333 TRACE_VALUE_NUMBERING(tty->print_cr("using loop invariant code motion loop_header = %d", loop_header->block_id())); | |
334 TRACE_VALUE_NUMBERING(tty->print_cr("** loop invariant code motion for short loop B%d", loop_header->block_id())); | |
335 | |
336 BlockBegin* insertion_block = loop_header->dominator(); | |
337 if (insertion_block->number_of_preds() == 0) { | |
338 return; // only the entry block does not have a predecessor | |
339 } | |
340 | |
341 assert(insertion_block->end()->as_Base() == NULL, "cannot insert into entry block"); | |
342 _insertion_point = insertion_block->end()->prev(); | |
9081
84ab5667f290
8011706: specjvm2008 test xml.transform gets array bound exception with c1
roland
parents:
8860
diff
changeset
|
343 _insert_is_pred = loop_header->is_predecessor(insertion_block); |
8860 | 344 |
345 BlockEnd *block_end = insertion_block->end(); | |
346 _state = block_end->state_before(); | |
347 | |
348 if (!_state) { | |
349 // If, TableSwitch and LookupSwitch always have state_before when | |
350 // loop invariant code motion happens.. | |
351 assert(block_end->as_Goto(), "Block has to be goto"); | |
352 _state = block_end->state(); | |
353 } | |
354 | |
355 // the loop_blocks are filled by going backward from the loop header, so this processing order is best | |
356 assert(loop_blocks->at(0) == loop_header, "loop header must be first loop block"); | |
357 process_block(loop_header); | |
358 for (int i = loop_blocks->length() - 1; i >= 1; i--) { | |
359 process_block(loop_blocks->at(i)); | |
360 } | |
361 } | |
362 | |
363 void LoopInvariantCodeMotion::process_block(BlockBegin* block) { | |
364 TRACE_VALUE_NUMBERING(tty->print_cr("processing block B%d", block->block_id())); | |
365 | |
366 Instruction* prev = block; | |
367 Instruction* cur = block->next(); | |
368 | |
369 while (cur != NULL) { | |
370 | |
371 // determine if cur instruction is loop invariant | |
372 // only selected instruction types are processed here | |
373 bool cur_invariant = false; | |
374 | |
375 if (cur->as_Constant() != NULL) { | |
376 cur_invariant = !cur->can_trap(); | |
377 } else if (cur->as_ArithmeticOp() != NULL || cur->as_LogicOp() != NULL || cur->as_ShiftOp() != NULL) { | |
378 assert(cur->as_Op2() != NULL, "must be Op2"); | |
379 Op2* op2 = (Op2*)cur; | |
380 cur_invariant = !op2->can_trap() && is_invariant(op2->x()) && is_invariant(op2->y()); | |
381 } else if (cur->as_LoadField() != NULL) { | |
382 LoadField* lf = (LoadField*)cur; | |
383 // deoptimizes on NullPointerException | |
9081
84ab5667f290
8011706: specjvm2008 test xml.transform gets array bound exception with c1
roland
parents:
8860
diff
changeset
|
384 cur_invariant = !lf->needs_patching() && !lf->field()->is_volatile() && !_short_loop_optimizer->has_field_store(lf->field()->type()->basic_type()) && is_invariant(lf->obj()) && _insert_is_pred; |
8860 | 385 } else if (cur->as_ArrayLength() != NULL) { |
386 ArrayLength *length = cur->as_ArrayLength(); | |
387 cur_invariant = is_invariant(length->array()); | |
388 } else if (cur->as_LoadIndexed() != NULL) { | |
389 LoadIndexed *li = (LoadIndexed *)cur->as_LoadIndexed(); | |
9081
84ab5667f290
8011706: specjvm2008 test xml.transform gets array bound exception with c1
roland
parents:
8860
diff
changeset
|
390 cur_invariant = !_short_loop_optimizer->has_indexed_store(as_BasicType(cur->type())) && is_invariant(li->array()) && is_invariant(li->index()) && _insert_is_pred; |
8860 | 391 } |
392 | |
393 if (cur_invariant) { | |
394 // perform value numbering and mark instruction as loop-invariant | |
395 _gvn->substitute(cur); | |
396 | |
397 if (cur->as_Constant() == NULL) { | |
398 // ensure that code for non-constant instructions is always generated | |
399 cur->pin(); | |
400 } | |
401 | |
402 // remove cur instruction from loop block and append it to block before loop | |
403 Instruction* next = cur->next(); | |
404 Instruction* in = _insertion_point->next(); | |
405 _insertion_point = _insertion_point->set_next(cur); | |
406 cur->set_next(in); | |
407 | |
408 // Deoptimize on exception | |
409 cur->set_flag(Instruction::DeoptimizeOnException, true); | |
410 | |
411 // Clear exception handlers | |
412 cur->set_exception_handlers(NULL); | |
413 | |
414 TRACE_VALUE_NUMBERING(tty->print_cr("Instruction %c%d is loop invariant", cur->type()->tchar(), cur->id())); | |
415 | |
416 if (cur->state_before() != NULL) { | |
417 cur->set_state_before(_state->copy()); | |
418 } | |
419 if (cur->exception_state() != NULL) { | |
420 cur->set_exception_state(_state->copy()); | |
421 } | |
422 | |
423 cur = prev->set_next(next); | |
424 | |
425 } else { | |
426 prev = cur; | |
427 cur = cur->next(); | |
428 } | |
429 } | |
430 } | |
0 | 431 |
432 bool ShortLoopOptimizer::process(BlockBegin* loop_header) { | |
433 TRACE_VALUE_NUMBERING(tty->print_cr("** loop header block")); | |
434 | |
435 _too_complicated_loop = false; | |
436 _loop_blocks.clear(); | |
437 _loop_blocks.append(loop_header); | |
438 | |
439 for (int i = 0; i < _loop_blocks.length(); i++) { | |
440 BlockBegin* block = _loop_blocks.at(i); | |
441 TRACE_VALUE_NUMBERING(tty->print_cr("processing loop block B%d", block->block_id())); | |
442 | |
443 if (block->is_set(BlockBegin::exception_entry_flag)) { | |
444 // this would be too complicated | |
445 return false; | |
446 } | |
447 | |
448 // add predecessors to worklist | |
449 for (int j = block->number_of_preds() - 1; j >= 0; j--) { | |
450 BlockBegin* pred = block->pred_at(j); | |
451 | |
8860 | 452 if (pred->is_set(BlockBegin::osr_entry_flag)) { |
453 return false; | |
454 } | |
455 | |
0 | 456 ValueMap* pred_map = value_map_of(pred); |
457 if (pred_map != NULL) { | |
458 current_map()->kill_map(pred_map); | |
459 } else if (!_loop_blocks.contains(pred)) { | |
460 if (_loop_blocks.length() >= ValueMapMaxLoopSize) { | |
461 return false; | |
462 } | |
463 _loop_blocks.append(pred); | |
464 } | |
465 } | |
466 | |
467 // use the instruction visitor for killing values | |
468 for (Value instr = block->next(); instr != NULL; instr = instr->next()) { | |
469 instr->visit(this); | |
470 if (_too_complicated_loop) { | |
471 return false; | |
472 } | |
473 } | |
474 } | |
475 | |
8860 | 476 bool optimistic = this->_gvn->compilation()->is_optimistic(); |
477 | |
478 if (UseLoopInvariantCodeMotion && optimistic) { | |
479 LoopInvariantCodeMotion code_motion(this, _gvn, loop_header, &_loop_blocks); | |
480 } | |
481 | |
0 | 482 TRACE_VALUE_NUMBERING(tty->print_cr("** loop successfully optimized")); |
483 return true; | |
484 } | |
485 | |
486 | |
487 GlobalValueNumbering::GlobalValueNumbering(IR* ir) | |
488 : _current_map(NULL) | |
489 , _value_maps(ir->linear_scan_order()->length(), NULL) | |
8860 | 490 , _compilation(ir->compilation()) |
0 | 491 { |
492 TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering")); | |
493 | |
494 ShortLoopOptimizer short_loop_optimizer(this); | |
495 | |
496 BlockList* blocks = ir->linear_scan_order(); | |
497 int num_blocks = blocks->length(); | |
498 | |
499 BlockBegin* start_block = blocks->at(0); | |
500 assert(start_block == ir->start() && start_block->number_of_preds() == 0 && start_block->dominator() == NULL, "must be start block"); | |
501 assert(start_block->next()->as_Base() != NULL && start_block->next()->next() == NULL, "start block must not have instructions"); | |
502 | |
8860 | 503 // method parameters are not linked in instructions list, so process them separateley |
504 for_each_state_value(start_block->state(), value, | |
505 assert(value->as_Local() != NULL, "only method parameters allowed"); | |
506 set_processed(value); | |
507 ); | |
508 | |
0 | 509 // initial, empty value map with nesting 0 |
510 set_value_map_of(start_block, new ValueMap()); | |
511 | |
512 for (int i = 1; i < num_blocks; i++) { | |
513 BlockBegin* block = blocks->at(i); | |
514 TRACE_VALUE_NUMBERING(tty->print_cr("**** processing block B%d", block->block_id())); | |
515 | |
516 int num_preds = block->number_of_preds(); | |
517 assert(num_preds > 0, "block must have predecessors"); | |
518 | |
519 BlockBegin* dominator = block->dominator(); | |
520 assert(dominator != NULL, "dominator must exist"); | |
521 assert(value_map_of(dominator) != NULL, "value map of dominator must exist"); | |
522 | |
523 // create new value map with increased nesting | |
524 _current_map = new ValueMap(value_map_of(dominator)); | |
525 | |
8860 | 526 if (num_preds == 1 && !block->is_set(BlockBegin::exception_entry_flag)) { |
0 | 527 assert(dominator == block->pred_at(0), "dominator must be equal to predecessor"); |
528 // nothing to do here | |
529 | |
530 } else if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
531 // block has incoming backward branches -> try to optimize short loops | |
532 if (!short_loop_optimizer.process(block)) { | |
533 // loop is too complicated, so kill all memory loads because there might be | |
534 // stores to them in the loop | |
535 current_map()->kill_memory(); | |
536 } | |
537 | |
538 } else { | |
539 // only incoming forward branches that are already processed | |
540 for (int j = 0; j < num_preds; j++) { | |
541 BlockBegin* pred = block->pred_at(j); | |
542 ValueMap* pred_map = value_map_of(pred); | |
543 | |
544 if (pred_map != NULL) { | |
545 // propagate killed values of the predecessor to this block | |
546 current_map()->kill_map(value_map_of(pred)); | |
547 } else { | |
548 // kill all memory loads because predecessor not yet processed | |
549 // (this can happen with non-natural loops and OSR-compiles) | |
550 current_map()->kill_memory(); | |
551 } | |
552 } | |
553 } | |
554 | |
8860 | 555 // phi functions are not linked in instructions list, so process them separateley |
556 for_each_phi_fun(block, phi, | |
557 set_processed(phi); | |
558 ); | |
0 | 559 |
560 TRACE_VALUE_NUMBERING(tty->print("value map before processing block: "); current_map()->print()); | |
561 | |
562 // visit all instructions of this block | |
563 for (Value instr = block->next(); instr != NULL; instr = instr->next()) { | |
564 // check if instruction kills any values | |
565 instr->visit(this); | |
8860 | 566 // perform actual value numbering |
567 substitute(instr); | |
0 | 568 } |
569 | |
570 // remember value map for successors | |
571 set_value_map_of(block, current_map()); | |
572 } | |
573 | |
8860 | 574 if (_has_substitutions) { |
0 | 575 SubstitutionResolver resolver(ir); |
576 } | |
577 | |
578 TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics()); | |
579 } | |
8860 | 580 |
581 void GlobalValueNumbering::substitute(Instruction* instr) { | |
582 assert(!instr->has_subst(), "substitution already set"); | |
583 Value subst = current_map()->find_insert(instr); | |
584 if (subst != instr) { | |
585 assert(!subst->has_subst(), "can't have a substitution"); | |
586 | |
587 TRACE_VALUE_NUMBERING(tty->print_cr("substitution for %d set to %d", instr->id(), subst->id())); | |
588 instr->set_subst(subst); | |
589 _has_substitutions = true; | |
590 } | |
591 set_processed(instr); | |
592 } |