Mercurial > hg > truffle
annotate src/share/vm/c1/c1_ValueMap.cpp @ 1931:48bbaead8b6c
Adjustments after merge with OpenJDK repository.
author | Thomas Wuerthinger <wuerthinger@ssw.jku.at> |
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date | Tue, 30 Nov 2010 16:39:35 +0100 |
parents | c18cbe5936b8 |
children | f95d63e2154a |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2005, 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
25 #include "incls/_precompiled.incl" | |
26 #include "incls/_c1_ValueMap.cpp.incl" | |
27 | |
28 | |
29 #ifndef PRODUCT | |
30 | |
31 int ValueMap::_number_of_finds = 0; | |
32 int ValueMap::_number_of_hits = 0; | |
33 int ValueMap::_number_of_kills = 0; | |
34 | |
35 #define TRACE_VALUE_NUMBERING(code) if (PrintValueNumbering) { code; } | |
36 | |
37 #else | |
38 | |
39 #define TRACE_VALUE_NUMBERING(code) | |
40 | |
41 #endif | |
42 | |
43 | |
44 ValueMap::ValueMap() | |
45 : _nesting(0) | |
46 , _entries(ValueMapInitialSize, NULL) | |
47 , _killed_values() | |
48 , _entry_count(0) | |
49 { | |
50 NOT_PRODUCT(reset_statistics()); | |
51 } | |
52 | |
53 | |
54 ValueMap::ValueMap(ValueMap* old) | |
55 : _nesting(old->_nesting + 1) | |
56 , _entries(old->_entries.length()) | |
57 , _killed_values() | |
58 , _entry_count(old->_entry_count) | |
59 { | |
60 for (int i = size() - 1; i >= 0; i--) { | |
61 _entries.at_put(i, old->entry_at(i)); | |
62 } | |
63 _killed_values.set_from(&old->_killed_values); | |
64 } | |
65 | |
66 | |
67 void ValueMap::increase_table_size() { | |
68 int old_size = size(); | |
69 int new_size = old_size * 2 + 1; | |
70 | |
71 ValueMapEntryList worklist(8); | |
72 ValueMapEntryArray new_entries(new_size, NULL); | |
73 int new_entry_count = 0; | |
74 | |
75 TRACE_VALUE_NUMBERING(tty->print_cr("increasing table size from %d to %d", old_size, new_size)); | |
76 | |
77 for (int i = old_size - 1; i >= 0; i--) { | |
78 ValueMapEntry* entry; | |
79 for (entry = entry_at(i); entry != NULL; entry = entry->next()) { | |
80 if (!is_killed(entry->value())) { | |
81 worklist.push(entry); | |
82 } | |
83 } | |
84 | |
85 while (!worklist.is_empty()) { | |
86 entry = worklist.pop(); | |
87 int new_index = entry_index(entry->hash(), new_size); | |
88 | |
89 if (entry->nesting() != nesting() && new_entries.at(new_index) != entry->next()) { | |
90 // changing entries with a lower nesting than the current nesting of the table | |
91 // is not allowed because then the same entry is contained in multiple value maps. | |
92 // clone entry when next-pointer must be changed | |
93 entry = new ValueMapEntry(entry->hash(), entry->value(), entry->nesting(), NULL); | |
94 } | |
95 entry->set_next(new_entries.at(new_index)); | |
96 new_entries.at_put(new_index, entry); | |
97 new_entry_count++; | |
98 } | |
99 } | |
100 | |
101 _entries = new_entries; | |
102 _entry_count = new_entry_count; | |
103 } | |
104 | |
105 | |
106 Value ValueMap::find_insert(Value x) { | |
107 const intx hash = x->hash(); | |
108 if (hash != 0) { | |
109 // 0 hash means: exclude from value numbering | |
110 NOT_PRODUCT(_number_of_finds++); | |
111 | |
112 for (ValueMapEntry* entry = entry_at(entry_index(hash, size())); entry != NULL; entry = entry->next()) { | |
113 if (entry->hash() == hash) { | |
114 Value f = entry->value(); | |
115 | |
116 if (!is_killed(f) && f->is_equal(x)) { | |
117 NOT_PRODUCT(_number_of_hits++); | |
118 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())); | |
119 | |
120 if (entry->nesting() != nesting() && f->as_Constant() == NULL) { | |
121 // non-constant values of of another block must be pinned, | |
122 // otherwise it is possible that they are not evaluated | |
123 f->pin(Instruction::PinGlobalValueNumbering); | |
124 } | |
125 | |
126 return f; | |
127 | |
128 } | |
129 } | |
130 } | |
131 | |
132 // x not found, so insert it | |
133 if (entry_count() >= size_threshold()) { | |
134 increase_table_size(); | |
135 } | |
136 int idx = entry_index(hash, size()); | |
137 _entries.at_put(idx, new ValueMapEntry(hash, x, nesting(), entry_at(idx))); | |
138 _entry_count++; | |
139 | |
140 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())); | |
141 } | |
142 | |
143 return x; | |
144 } | |
145 | |
146 | |
147 #define GENERIC_KILL_VALUE(must_kill_implementation) \ | |
148 NOT_PRODUCT(_number_of_kills++); \ | |
149 \ | |
150 for (int i = size() - 1; i >= 0; i--) { \ | |
151 ValueMapEntry* prev_entry = NULL; \ | |
152 for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { \ | |
153 Value value = entry->value(); \ | |
154 \ | |
155 must_kill_implementation(must_kill, entry, value) \ | |
156 \ | |
157 if (must_kill) { \ | |
158 kill_value(value); \ | |
159 \ | |
160 if (prev_entry == NULL) { \ | |
161 _entries.at_put(i, entry->next()); \ | |
162 _entry_count--; \ | |
163 } else if (prev_entry->nesting() == nesting()) { \ | |
164 prev_entry->set_next(entry->next()); \ | |
165 _entry_count--; \ | |
166 } else { \ | |
167 prev_entry = entry; \ | |
168 } \ | |
169 \ | |
170 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())); \ | |
171 } else { \ | |
172 prev_entry = entry; \ | |
173 } \ | |
174 } \ | |
175 } \ | |
176 | |
177 #define MUST_KILL_MEMORY(must_kill, entry, value) \ | |
178 bool must_kill = value->as_LoadField() != NULL || value->as_LoadIndexed() != NULL; | |
179 | |
180 #define MUST_KILL_ARRAY(must_kill, entry, value) \ | |
181 bool must_kill = value->as_LoadIndexed() != NULL \ | |
182 && value->type()->tag() == type->tag(); | |
183 | |
184 #define MUST_KILL_FIELD(must_kill, entry, value) \ | |
185 /* ciField's are not unique; must compare their contents */ \ | |
186 LoadField* lf = value->as_LoadField(); \ | |
187 bool must_kill = lf != NULL \ | |
188 && lf->field()->holder() == field->holder() \ | |
189 && lf->field()->offset() == field->offset(); | |
190 | |
191 #define MUST_KILL_EXCEPTION(must_kill, entry, value) \ | |
192 assert(entry->nesting() < nesting(), "must not find bigger nesting than current"); \ | |
193 bool must_kill = (entry->nesting() == nesting() - 1); | |
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 | |
204 void ValueMap::kill_field(ciField* field) { | |
205 GENERIC_KILL_VALUE(MUST_KILL_FIELD); | |
206 } | |
207 | |
208 void ValueMap::kill_exception() { | |
209 GENERIC_KILL_VALUE(MUST_KILL_EXCEPTION); | |
210 } | |
211 | |
212 | |
213 void ValueMap::kill_map(ValueMap* map) { | |
214 assert(is_global_value_numbering(), "only for global value numbering"); | |
215 _killed_values.set_union(&map->_killed_values); | |
216 } | |
217 | |
218 void ValueMap::kill_all() { | |
219 assert(is_local_value_numbering(), "only for local value numbering"); | |
220 for (int i = size() - 1; i >= 0; i--) { | |
221 _entries.at_put(i, NULL); | |
222 } | |
223 _entry_count = 0; | |
224 } | |
225 | |
226 | |
227 #ifndef PRODUCT | |
228 | |
229 void ValueMap::print() { | |
230 tty->print_cr("(size %d, entries %d, nesting %d)", size(), entry_count(), nesting()); | |
231 | |
232 int entries = 0; | |
233 for (int i = 0; i < size(); i++) { | |
234 if (entry_at(i) != NULL) { | |
235 tty->print(" %2d: ", i); | |
236 for (ValueMapEntry* entry = entry_at(i); entry != NULL; entry = entry->next()) { | |
237 Value value = entry->value(); | |
238 tty->print("%s %c%d (%s%d) -> ", value->name(), value->type()->tchar(), value->id(), is_killed(value) ? "x" : "", entry->nesting()); | |
239 entries++; | |
240 } | |
241 tty->print_cr("NULL"); | |
242 } | |
243 } | |
244 | |
245 _killed_values.print(); | |
246 assert(entry_count() == entries, "entry_count incorrect"); | |
247 } | |
248 | |
249 void ValueMap::reset_statistics() { | |
250 _number_of_finds = 0; | |
251 _number_of_hits = 0; | |
252 _number_of_kills = 0; | |
253 } | |
254 | |
255 void ValueMap::print_statistics() { | |
256 float hit_rate = 0; | |
257 if (_number_of_finds != 0) { | |
258 hit_rate = (float)_number_of_hits / _number_of_finds; | |
259 } | |
260 | |
261 tty->print_cr("finds:%3d hits:%3d kills:%3d hit rate: %1.4f", _number_of_finds, _number_of_hits, _number_of_kills, hit_rate); | |
262 } | |
263 | |
264 #endif | |
265 | |
266 | |
267 | |
268 class ShortLoopOptimizer : public ValueNumberingVisitor { | |
269 private: | |
270 GlobalValueNumbering* _gvn; | |
271 BlockList _loop_blocks; | |
272 bool _too_complicated_loop; | |
273 | |
274 // simplified access to methods of GlobalValueNumbering | |
275 ValueMap* current_map() { return _gvn->current_map(); } | |
276 ValueMap* value_map_of(BlockBegin* block) { return _gvn->value_map_of(block); } | |
277 | |
278 // implementation for abstract methods of ValueNumberingVisitor | |
279 void kill_memory() { _too_complicated_loop = true; } | |
280 void kill_field(ciField* field) { current_map()->kill_field(field); }; | |
281 void kill_array(ValueType* type) { current_map()->kill_array(type); }; | |
282 | |
283 public: | |
284 ShortLoopOptimizer(GlobalValueNumbering* gvn) | |
285 : _gvn(gvn) | |
286 , _loop_blocks(ValueMapMaxLoopSize) | |
287 , _too_complicated_loop(false) | |
288 { | |
289 } | |
290 | |
291 bool process(BlockBegin* loop_header); | |
292 }; | |
293 | |
294 | |
295 bool ShortLoopOptimizer::process(BlockBegin* loop_header) { | |
296 TRACE_VALUE_NUMBERING(tty->print_cr("** loop header block")); | |
297 | |
298 _too_complicated_loop = false; | |
299 _loop_blocks.clear(); | |
300 _loop_blocks.append(loop_header); | |
301 | |
302 for (int i = 0; i < _loop_blocks.length(); i++) { | |
303 BlockBegin* block = _loop_blocks.at(i); | |
304 TRACE_VALUE_NUMBERING(tty->print_cr("processing loop block B%d", block->block_id())); | |
305 | |
306 if (block->is_set(BlockBegin::exception_entry_flag)) { | |
307 // this would be too complicated | |
308 return false; | |
309 } | |
310 | |
311 // add predecessors to worklist | |
312 for (int j = block->number_of_preds() - 1; j >= 0; j--) { | |
313 BlockBegin* pred = block->pred_at(j); | |
314 | |
315 ValueMap* pred_map = value_map_of(pred); | |
316 if (pred_map != NULL) { | |
317 current_map()->kill_map(pred_map); | |
318 } else if (!_loop_blocks.contains(pred)) { | |
319 if (_loop_blocks.length() >= ValueMapMaxLoopSize) { | |
320 return false; | |
321 } | |
322 _loop_blocks.append(pred); | |
323 } | |
324 } | |
325 | |
326 // use the instruction visitor for killing values | |
327 for (Value instr = block->next(); instr != NULL; instr = instr->next()) { | |
328 instr->visit(this); | |
329 if (_too_complicated_loop) { | |
330 return false; | |
331 } | |
332 } | |
333 } | |
334 | |
335 TRACE_VALUE_NUMBERING(tty->print_cr("** loop successfully optimized")); | |
336 return true; | |
337 } | |
338 | |
339 | |
340 GlobalValueNumbering::GlobalValueNumbering(IR* ir) | |
341 : _current_map(NULL) | |
342 , _value_maps(ir->linear_scan_order()->length(), NULL) | |
343 { | |
344 TRACE_VALUE_NUMBERING(tty->print_cr("****** start of global value numbering")); | |
345 | |
346 ShortLoopOptimizer short_loop_optimizer(this); | |
347 int subst_count = 0; | |
348 | |
349 BlockList* blocks = ir->linear_scan_order(); | |
350 int num_blocks = blocks->length(); | |
351 | |
352 BlockBegin* start_block = blocks->at(0); | |
353 assert(start_block == ir->start() && start_block->number_of_preds() == 0 && start_block->dominator() == NULL, "must be start block"); | |
354 assert(start_block->next()->as_Base() != NULL && start_block->next()->next() == NULL, "start block must not have instructions"); | |
355 | |
356 // initial, empty value map with nesting 0 | |
357 set_value_map_of(start_block, new ValueMap()); | |
358 | |
359 for (int i = 1; i < num_blocks; i++) { | |
360 BlockBegin* block = blocks->at(i); | |
361 TRACE_VALUE_NUMBERING(tty->print_cr("**** processing block B%d", block->block_id())); | |
362 | |
363 int num_preds = block->number_of_preds(); | |
364 assert(num_preds > 0, "block must have predecessors"); | |
365 | |
366 BlockBegin* dominator = block->dominator(); | |
367 assert(dominator != NULL, "dominator must exist"); | |
368 assert(value_map_of(dominator) != NULL, "value map of dominator must exist"); | |
369 | |
370 // create new value map with increased nesting | |
371 _current_map = new ValueMap(value_map_of(dominator)); | |
372 | |
373 if (num_preds == 1) { | |
374 assert(dominator == block->pred_at(0), "dominator must be equal to predecessor"); | |
375 // nothing to do here | |
376 | |
377 } else if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
378 // block has incoming backward branches -> try to optimize short loops | |
379 if (!short_loop_optimizer.process(block)) { | |
380 // loop is too complicated, so kill all memory loads because there might be | |
381 // stores to them in the loop | |
382 current_map()->kill_memory(); | |
383 } | |
384 | |
385 } else { | |
386 // only incoming forward branches that are already processed | |
387 for (int j = 0; j < num_preds; j++) { | |
388 BlockBegin* pred = block->pred_at(j); | |
389 ValueMap* pred_map = value_map_of(pred); | |
390 | |
391 if (pred_map != NULL) { | |
392 // propagate killed values of the predecessor to this block | |
393 current_map()->kill_map(value_map_of(pred)); | |
394 } else { | |
395 // kill all memory loads because predecessor not yet processed | |
396 // (this can happen with non-natural loops and OSR-compiles) | |
397 current_map()->kill_memory(); | |
398 } | |
399 } | |
400 } | |
401 | |
402 if (block->is_set(BlockBegin::exception_entry_flag)) { | |
403 current_map()->kill_exception(); | |
404 } | |
405 | |
406 TRACE_VALUE_NUMBERING(tty->print("value map before processing block: "); current_map()->print()); | |
407 | |
408 // visit all instructions of this block | |
409 for (Value instr = block->next(); instr != NULL; instr = instr->next()) { | |
410 assert(!instr->has_subst(), "substitution already set"); | |
411 | |
412 // check if instruction kills any values | |
413 instr->visit(this); | |
414 | |
415 if (instr->hash() != 0) { | |
416 Value f = current_map()->find_insert(instr); | |
417 if (f != instr) { | |
418 assert(!f->has_subst(), "can't have a substitution"); | |
419 instr->set_subst(f); | |
420 subst_count++; | |
421 } | |
422 } | |
423 } | |
424 | |
425 // remember value map for successors | |
426 set_value_map_of(block, current_map()); | |
427 } | |
428 | |
429 if (subst_count != 0) { | |
430 SubstitutionResolver resolver(ir); | |
431 } | |
432 | |
433 TRACE_VALUE_NUMBERING(tty->print("****** end of global value numbering. "); ValueMap::print_statistics()); | |
434 } |