Mercurial > hg > truffle
annotate src/share/vm/c1/c1_Optimizer.cpp @ 9020:627dc359e918
Use correct method to access constant pool
author | Christian Wimmer <christian.wimmer@oracle.com> |
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date | Thu, 11 Apr 2013 15:39:55 -0700 |
parents | 46f6f063b272 |
children | acadb114c818 |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1999, 2012, 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 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "c1/c1_Canonicalizer.hpp" | |
27 #include "c1/c1_Optimizer.hpp" | |
28 #include "c1/c1_ValueMap.hpp" | |
29 #include "c1/c1_ValueSet.hpp" | |
30 #include "c1/c1_ValueStack.hpp" | |
31 #include "utilities/bitMap.inline.hpp" | |
6843 | 32 #include "compiler/compileLog.hpp" |
0 | 33 |
34 define_array(ValueSetArray, ValueSet*); | |
35 define_stack(ValueSetList, ValueSetArray); | |
36 | |
37 | |
38 Optimizer::Optimizer(IR* ir) { | |
39 assert(ir->is_valid(), "IR must be valid"); | |
40 _ir = ir; | |
41 } | |
42 | |
43 class CE_Eliminator: public BlockClosure { | |
44 private: | |
45 IR* _hir; | |
46 int _cee_count; // the number of CEs successfully eliminated | |
1899 | 47 int _ifop_count; // the number of IfOps successfully simplified |
0 | 48 int _has_substitution; |
49 | |
50 public: | |
1899 | 51 CE_Eliminator(IR* hir) : _cee_count(0), _ifop_count(0), _hir(hir) { |
0 | 52 _has_substitution = false; |
53 _hir->iterate_preorder(this); | |
54 if (_has_substitution) { | |
1899 | 55 // substituted some ifops/phis, so resolve the substitution |
0 | 56 SubstitutionResolver sr(_hir); |
57 } | |
6843 | 58 |
59 CompileLog* log = _hir->compilation()->log(); | |
60 if (log != NULL) | |
61 log->set_context("optimize name='cee'"); | |
0 | 62 } |
6843 | 63 |
64 ~CE_Eliminator() { | |
65 CompileLog* log = _hir->compilation()->log(); | |
66 if (log != NULL) | |
67 log->clear_context(); // skip marker if nothing was printed | |
68 } | |
69 | |
0 | 70 int cee_count() const { return _cee_count; } |
1899 | 71 int ifop_count() const { return _ifop_count; } |
0 | 72 |
73 void adjust_exception_edges(BlockBegin* block, BlockBegin* sux) { | |
74 int e = sux->number_of_exception_handlers(); | |
75 for (int i = 0; i < e; i++) { | |
76 BlockBegin* xhandler = sux->exception_handler_at(i); | |
77 block->add_exception_handler(xhandler); | |
78 | |
79 assert(xhandler->is_predecessor(sux), "missing predecessor"); | |
80 if (sux->number_of_preds() == 0) { | |
81 // sux is disconnected from graph so disconnect from exception handlers | |
82 xhandler->remove_predecessor(sux); | |
83 } | |
84 if (!xhandler->is_predecessor(block)) { | |
85 xhandler->add_predecessor(block); | |
86 } | |
87 } | |
88 } | |
89 | |
1899 | 90 virtual void block_do(BlockBegin* block); |
91 | |
92 private: | |
93 Value make_ifop(Value x, Instruction::Condition cond, Value y, Value tval, Value fval); | |
94 }; | |
0 | 95 |
1899 | 96 void CE_Eliminator::block_do(BlockBegin* block) { |
97 // 1) find conditional expression | |
98 // check if block ends with an If | |
99 If* if_ = block->end()->as_If(); | |
100 if (if_ == NULL) return; | |
0 | 101 |
1899 | 102 // check if If works on int or object types |
103 // (we cannot handle If's working on long, float or doubles yet, | |
104 // since IfOp doesn't support them - these If's show up if cmp | |
105 // operations followed by If's are eliminated) | |
106 ValueType* if_type = if_->x()->type(); | |
107 if (!if_type->is_int() && !if_type->is_object()) return; | |
0 | 108 |
1899 | 109 BlockBegin* t_block = if_->tsux(); |
110 BlockBegin* f_block = if_->fsux(); | |
111 Instruction* t_cur = t_block->next(); | |
112 Instruction* f_cur = f_block->next(); | |
0 | 113 |
1899 | 114 // one Constant may be present between BlockBegin and BlockEnd |
115 Value t_const = NULL; | |
116 Value f_const = NULL; | |
117 if (t_cur->as_Constant() != NULL && !t_cur->can_trap()) { | |
118 t_const = t_cur; | |
119 t_cur = t_cur->next(); | |
120 } | |
121 if (f_cur->as_Constant() != NULL && !f_cur->can_trap()) { | |
122 f_const = f_cur; | |
123 f_cur = f_cur->next(); | |
124 } | |
0 | 125 |
1899 | 126 // check if both branches end with a goto |
127 Goto* t_goto = t_cur->as_Goto(); | |
128 if (t_goto == NULL) return; | |
129 Goto* f_goto = f_cur->as_Goto(); | |
130 if (f_goto == NULL) return; | |
0 | 131 |
1899 | 132 // check if both gotos merge into the same block |
133 BlockBegin* sux = t_goto->default_sux(); | |
134 if (sux != f_goto->default_sux()) return; | |
0 | 135 |
1899 | 136 // check if at least one word was pushed on sux_state |
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137 // inlining depths must match |
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138 ValueStack* if_state = if_->state(); |
1899 | 139 ValueStack* sux_state = sux->state(); |
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140 if (if_state->scope()->level() > sux_state->scope()->level()) { |
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141 while (sux_state->scope() != if_state->scope()) { |
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142 if_state = if_state->caller_state(); |
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143 assert(if_state != NULL, "states do not match up"); |
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144 } |
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145 } else if (if_state->scope()->level() < sux_state->scope()->level()) { |
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146 while (sux_state->scope() != if_state->scope()) { |
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147 sux_state = sux_state->caller_state(); |
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148 assert(sux_state != NULL, "states do not match up"); |
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149 } |
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150 } |
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151 |
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152 if (sux_state->stack_size() <= if_state->stack_size()) return; |
0 | 153 |
1899 | 154 // check if phi function is present at end of successor stack and that |
155 // only this phi was pushed on the stack | |
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156 Value sux_phi = sux_state->stack_at(if_state->stack_size()); |
1899 | 157 if (sux_phi == NULL || sux_phi->as_Phi() == NULL || sux_phi->as_Phi()->block() != sux) return; |
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158 if (sux_phi->type()->size() != sux_state->stack_size() - if_state->stack_size()) return; |
0 | 159 |
1899 | 160 // get the values that were pushed in the true- and false-branch |
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161 Value t_value = t_goto->state()->stack_at(if_state->stack_size()); |
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162 Value f_value = f_goto->state()->stack_at(if_state->stack_size()); |
1899 | 163 |
164 // backend does not support floats | |
165 assert(t_value->type()->base() == f_value->type()->base(), "incompatible types"); | |
166 if (t_value->type()->is_float_kind()) return; | |
0 | 167 |
1899 | 168 // check that successor has no other phi functions but sux_phi |
169 // this can happen when t_block or f_block contained additonal stores to local variables | |
170 // that are no longer represented by explicit instructions | |
171 for_each_phi_fun(sux, phi, | |
172 if (phi != sux_phi) return; | |
173 ); | |
174 // true and false blocks can't have phis | |
175 for_each_phi_fun(t_block, phi, return; ); | |
176 for_each_phi_fun(f_block, phi, return; ); | |
177 | |
178 // 2) substitute conditional expression | |
179 // with an IfOp followed by a Goto | |
180 // cut if_ away and get node before | |
8860 | 181 Instruction* cur_end = if_->prev(); |
0 | 182 |
1899 | 183 // append constants of true- and false-block if necessary |
184 // clone constants because original block must not be destroyed | |
185 assert((t_value != f_const && f_value != t_const) || t_const == f_const, "mismatch"); | |
186 if (t_value == t_const) { | |
187 t_value = new Constant(t_const->type()); | |
188 NOT_PRODUCT(t_value->set_printable_bci(if_->printable_bci())); | |
189 cur_end = cur_end->set_next(t_value); | |
190 } | |
191 if (f_value == f_const) { | |
192 f_value = new Constant(f_const->type()); | |
193 NOT_PRODUCT(f_value->set_printable_bci(if_->printable_bci())); | |
194 cur_end = cur_end->set_next(f_value); | |
195 } | |
0 | 196 |
1899 | 197 Value result = make_ifop(if_->x(), if_->cond(), if_->y(), t_value, f_value); |
198 assert(result != NULL, "make_ifop must return a non-null instruction"); | |
199 if (!result->is_linked() && result->can_be_linked()) { | |
1819 | 200 NOT_PRODUCT(result->set_printable_bci(if_->printable_bci())); |
201 cur_end = cur_end->set_next(result); | |
1899 | 202 } |
0 | 203 |
1899 | 204 // append Goto to successor |
8860 | 205 ValueStack* state_before = if_->state_before(); |
1899 | 206 Goto* goto_ = new Goto(sux, state_before, if_->is_safepoint() || t_goto->is_safepoint() || f_goto->is_safepoint()); |
207 | |
208 // prepare state for Goto | |
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209 ValueStack* goto_state = if_state; |
1899 | 210 goto_state = goto_state->copy(ValueStack::StateAfter, goto_state->bci()); |
211 goto_state->push(result->type(), result); | |
212 assert(goto_state->is_same(sux_state), "states must match now"); | |
213 goto_->set_state(goto_state); | |
214 | |
215 cur_end = cur_end->set_next(goto_, goto_state->bci()); | |
216 | |
217 // Adjust control flow graph | |
218 BlockBegin::disconnect_edge(block, t_block); | |
219 BlockBegin::disconnect_edge(block, f_block); | |
220 if (t_block->number_of_preds() == 0) { | |
221 BlockBegin::disconnect_edge(t_block, sux); | |
222 } | |
223 adjust_exception_edges(block, t_block); | |
224 if (f_block->number_of_preds() == 0) { | |
225 BlockBegin::disconnect_edge(f_block, sux); | |
226 } | |
227 adjust_exception_edges(block, f_block); | |
228 | |
229 // update block end | |
230 block->set_end(goto_); | |
231 | |
232 // substitute the phi if possible | |
233 if (sux_phi->as_Phi()->operand_count() == 1) { | |
234 assert(sux_phi->as_Phi()->operand_at(0) == result, "screwed up phi"); | |
235 sux_phi->set_subst(result); | |
236 _has_substitution = true; | |
237 } | |
238 | |
239 // 3) successfully eliminated a conditional expression | |
240 _cee_count++; | |
241 if (PrintCEE) { | |
242 tty->print_cr("%d. CEE in B%d (B%d B%d)", cee_count(), block->block_id(), t_block->block_id(), f_block->block_id()); | |
243 tty->print_cr("%d. IfOp in B%d", ifop_count(), block->block_id()); | |
244 } | |
0 | 245 |
1899 | 246 _hir->verify(); |
247 } | |
248 | |
249 Value CE_Eliminator::make_ifop(Value x, Instruction::Condition cond, Value y, Value tval, Value fval) { | |
250 if (!OptimizeIfOps) { | |
251 return new IfOp(x, cond, y, tval, fval); | |
252 } | |
253 | |
254 tval = tval->subst(); | |
255 fval = fval->subst(); | |
256 if (tval == fval) { | |
257 _ifop_count++; | |
258 return tval; | |
259 } | |
260 | |
261 x = x->subst(); | |
262 y = y->subst(); | |
263 | |
264 Constant* y_const = y->as_Constant(); | |
265 if (y_const != NULL) { | |
266 IfOp* x_ifop = x->as_IfOp(); | |
267 if (x_ifop != NULL) { // x is an ifop, y is a constant | |
268 Constant* x_tval_const = x_ifop->tval()->subst()->as_Constant(); | |
269 Constant* x_fval_const = x_ifop->fval()->subst()->as_Constant(); | |
0 | 270 |
1899 | 271 if (x_tval_const != NULL && x_fval_const != NULL) { |
272 Instruction::Condition x_ifop_cond = x_ifop->cond(); | |
273 | |
274 Constant::CompareResult t_compare_res = x_tval_const->compare(cond, y_const); | |
275 Constant::CompareResult f_compare_res = x_fval_const->compare(cond, y_const); | |
276 | |
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277 // not_comparable here is a valid return in case we're comparing unloaded oop constants |
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278 if (t_compare_res != Constant::not_comparable && f_compare_res != Constant::not_comparable) { |
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279 Value new_tval = t_compare_res == Constant::cond_true ? tval : fval; |
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280 Value new_fval = f_compare_res == Constant::cond_true ? tval : fval; |
0 | 281 |
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282 _ifop_count++; |
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283 if (new_tval == new_fval) { |
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284 return new_tval; |
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285 } else { |
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286 return new IfOp(x_ifop->x(), x_ifop_cond, x_ifop->y(), new_tval, new_fval); |
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287 } |
1899 | 288 } |
289 } | |
290 } else { | |
291 Constant* x_const = x->as_Constant(); | |
292 if (x_const != NULL) { // x and y are constants | |
293 Constant::CompareResult x_compare_res = x_const->compare(cond, y_const); | |
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294 // not_comparable here is a valid return in case we're comparing unloaded oop constants |
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295 if (x_compare_res != Constant::not_comparable) { |
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296 _ifop_count++; |
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297 return x_compare_res == Constant::cond_true ? tval : fval; |
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298 } |
1899 | 299 } |
0 | 300 } |
301 } | |
1899 | 302 return new IfOp(x, cond, y, tval, fval); |
303 } | |
0 | 304 |
305 void Optimizer::eliminate_conditional_expressions() { | |
306 // find conditional expressions & replace them with IfOps | |
307 CE_Eliminator ce(ir()); | |
308 } | |
309 | |
310 class BlockMerger: public BlockClosure { | |
311 private: | |
312 IR* _hir; | |
313 int _merge_count; // the number of block pairs successfully merged | |
314 | |
315 public: | |
316 BlockMerger(IR* hir) | |
317 : _hir(hir) | |
318 , _merge_count(0) | |
319 { | |
320 _hir->iterate_preorder(this); | |
6843 | 321 CompileLog* log = _hir->compilation()->log(); |
322 if (log != NULL) | |
323 log->set_context("optimize name='eliminate_blocks'"); | |
324 } | |
325 | |
326 ~BlockMerger() { | |
327 CompileLog* log = _hir->compilation()->log(); | |
328 if (log != NULL) | |
329 log->clear_context(); // skip marker if nothing was printed | |
0 | 330 } |
331 | |
332 bool try_merge(BlockBegin* block) { | |
333 BlockEnd* end = block->end(); | |
334 if (end->as_Goto() != NULL) { | |
335 assert(end->number_of_sux() == 1, "end must have exactly one successor"); | |
336 // Note: It would be sufficient to check for the number of successors (= 1) | |
337 // in order to decide if this block can be merged potentially. That | |
338 // would then also include switch statements w/ only a default case. | |
339 // However, in that case we would need to make sure the switch tag | |
340 // expression is executed if it can produce observable side effects. | |
341 // We should probably have the canonicalizer simplifying such switch | |
342 // statements and then we are sure we don't miss these merge opportunities | |
343 // here (was bug - gri 7/7/99). | |
344 BlockBegin* sux = end->default_sux(); | |
345 if (sux->number_of_preds() == 1 && !sux->is_entry_block() && !end->is_safepoint()) { | |
346 // merge the two blocks | |
347 | |
348 #ifdef ASSERT | |
349 // verify that state at the end of block and at the beginning of sux are equal | |
350 // no phi functions must be present at beginning of sux | |
351 ValueStack* sux_state = sux->state(); | |
352 ValueStack* end_state = end->state(); | |
1819 | 353 |
354 assert(end_state->scope() == sux_state->scope(), "scopes must match"); | |
0 | 355 assert(end_state->stack_size() == sux_state->stack_size(), "stack not equal"); |
356 assert(end_state->locals_size() == sux_state->locals_size(), "locals not equal"); | |
357 | |
358 int index; | |
359 Value sux_value; | |
360 for_each_stack_value(sux_state, index, sux_value) { | |
361 assert(sux_value == end_state->stack_at(index), "stack not equal"); | |
362 } | |
363 for_each_local_value(sux_state, index, sux_value) { | |
364 assert(sux_value == end_state->local_at(index), "locals not equal"); | |
365 } | |
366 assert(sux_state->caller_state() == end_state->caller_state(), "caller not equal"); | |
367 #endif | |
368 | |
369 // find instruction before end & append first instruction of sux block | |
8860 | 370 Instruction* prev = end->prev(); |
0 | 371 Instruction* next = sux->next(); |
372 assert(prev->as_BlockEnd() == NULL, "must not be a BlockEnd"); | |
1819 | 373 prev->set_next(next); |
8860 | 374 prev->fixup_block_pointers(); |
0 | 375 sux->disconnect_from_graph(); |
376 block->set_end(sux->end()); | |
377 // add exception handlers of deleted block, if any | |
378 for (int k = 0; k < sux->number_of_exception_handlers(); k++) { | |
379 BlockBegin* xhandler = sux->exception_handler_at(k); | |
380 block->add_exception_handler(xhandler); | |
381 | |
382 // also substitute predecessor of exception handler | |
383 assert(xhandler->is_predecessor(sux), "missing predecessor"); | |
384 xhandler->remove_predecessor(sux); | |
385 if (!xhandler->is_predecessor(block)) { | |
386 xhandler->add_predecessor(block); | |
387 } | |
388 } | |
389 | |
390 // debugging output | |
391 _merge_count++; | |
392 if (PrintBlockElimination) { | |
393 tty->print_cr("%d. merged B%d & B%d (stack size = %d)", | |
394 _merge_count, block->block_id(), sux->block_id(), sux->state()->stack_size()); | |
395 } | |
396 | |
397 _hir->verify(); | |
398 | |
399 If* if_ = block->end()->as_If(); | |
400 if (if_) { | |
401 IfOp* ifop = if_->x()->as_IfOp(); | |
402 Constant* con = if_->y()->as_Constant(); | |
403 bool swapped = false; | |
404 if (!con || !ifop) { | |
405 ifop = if_->y()->as_IfOp(); | |
406 con = if_->x()->as_Constant(); | |
407 swapped = true; | |
408 } | |
409 if (con && ifop) { | |
410 Constant* tval = ifop->tval()->as_Constant(); | |
411 Constant* fval = ifop->fval()->as_Constant(); | |
412 if (tval && fval) { | |
413 // Find the instruction before if_, starting with ifop. | |
414 // When if_ and ifop are not in the same block, prev | |
415 // becomes NULL In such (rare) cases it is not | |
416 // profitable to perform the optimization. | |
417 Value prev = ifop; | |
418 while (prev != NULL && prev->next() != if_) { | |
419 prev = prev->next(); | |
420 } | |
421 | |
422 if (prev != NULL) { | |
423 Instruction::Condition cond = if_->cond(); | |
424 BlockBegin* tsux = if_->tsux(); | |
425 BlockBegin* fsux = if_->fsux(); | |
426 if (swapped) { | |
427 cond = Instruction::mirror(cond); | |
428 } | |
429 | |
430 BlockBegin* tblock = tval->compare(cond, con, tsux, fsux); | |
431 BlockBegin* fblock = fval->compare(cond, con, tsux, fsux); | |
432 if (tblock != fblock && !if_->is_safepoint()) { | |
433 If* newif = new If(ifop->x(), ifop->cond(), false, ifop->y(), | |
434 tblock, fblock, if_->state_before(), if_->is_safepoint()); | |
435 newif->set_state(if_->state()->copy()); | |
436 | |
437 assert(prev->next() == if_, "must be guaranteed by above search"); | |
1819 | 438 NOT_PRODUCT(newif->set_printable_bci(if_->printable_bci())); |
439 prev->set_next(newif); | |
0 | 440 block->set_end(newif); |
441 | |
442 _merge_count++; | |
443 if (PrintBlockElimination) { | |
444 tty->print_cr("%d. replaced If and IfOp at end of B%d with single If", _merge_count, block->block_id()); | |
445 } | |
446 | |
447 _hir->verify(); | |
448 } | |
449 } | |
450 } | |
451 } | |
452 } | |
453 | |
454 return true; | |
455 } | |
456 } | |
457 return false; | |
458 } | |
459 | |
460 virtual void block_do(BlockBegin* block) { | |
461 _hir->verify(); | |
462 // repeat since the same block may merge again | |
463 while (try_merge(block)) { | |
464 _hir->verify(); | |
465 } | |
466 } | |
467 }; | |
468 | |
469 | |
470 void Optimizer::eliminate_blocks() { | |
471 // merge blocks if possible | |
472 BlockMerger bm(ir()); | |
473 } | |
474 | |
475 | |
476 class NullCheckEliminator; | |
477 class NullCheckVisitor: public InstructionVisitor { | |
478 private: | |
479 NullCheckEliminator* _nce; | |
480 NullCheckEliminator* nce() { return _nce; } | |
481 | |
482 public: | |
483 NullCheckVisitor() {} | |
484 | |
485 void set_eliminator(NullCheckEliminator* nce) { _nce = nce; } | |
486 | |
487 void do_Phi (Phi* x); | |
488 void do_Local (Local* x); | |
489 void do_Constant (Constant* x); | |
490 void do_LoadField (LoadField* x); | |
491 void do_StoreField (StoreField* x); | |
492 void do_ArrayLength (ArrayLength* x); | |
493 void do_LoadIndexed (LoadIndexed* x); | |
494 void do_StoreIndexed (StoreIndexed* x); | |
495 void do_NegateOp (NegateOp* x); | |
496 void do_ArithmeticOp (ArithmeticOp* x); | |
497 void do_ShiftOp (ShiftOp* x); | |
498 void do_LogicOp (LogicOp* x); | |
499 void do_CompareOp (CompareOp* x); | |
500 void do_IfOp (IfOp* x); | |
501 void do_Convert (Convert* x); | |
502 void do_NullCheck (NullCheck* x); | |
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503 void do_TypeCast (TypeCast* x); |
0 | 504 void do_Invoke (Invoke* x); |
505 void do_NewInstance (NewInstance* x); | |
506 void do_NewTypeArray (NewTypeArray* x); | |
507 void do_NewObjectArray (NewObjectArray* x); | |
508 void do_NewMultiArray (NewMultiArray* x); | |
509 void do_CheckCast (CheckCast* x); | |
510 void do_InstanceOf (InstanceOf* x); | |
511 void do_MonitorEnter (MonitorEnter* x); | |
512 void do_MonitorExit (MonitorExit* x); | |
513 void do_Intrinsic (Intrinsic* x); | |
514 void do_BlockBegin (BlockBegin* x); | |
515 void do_Goto (Goto* x); | |
516 void do_If (If* x); | |
517 void do_IfInstanceOf (IfInstanceOf* x); | |
518 void do_TableSwitch (TableSwitch* x); | |
519 void do_LookupSwitch (LookupSwitch* x); | |
520 void do_Return (Return* x); | |
521 void do_Throw (Throw* x); | |
522 void do_Base (Base* x); | |
523 void do_OsrEntry (OsrEntry* x); | |
524 void do_ExceptionObject(ExceptionObject* x); | |
525 void do_RoundFP (RoundFP* x); | |
526 void do_UnsafeGetRaw (UnsafeGetRaw* x); | |
527 void do_UnsafePutRaw (UnsafePutRaw* x); | |
528 void do_UnsafeGetObject(UnsafeGetObject* x); | |
529 void do_UnsafePutObject(UnsafePutObject* x); | |
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530 void do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x); |
0 | 531 void do_UnsafePrefetchRead (UnsafePrefetchRead* x); |
532 void do_UnsafePrefetchWrite(UnsafePrefetchWrite* x); | |
533 void do_ProfileCall (ProfileCall* x); | |
1783 | 534 void do_ProfileInvoke (ProfileInvoke* x); |
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535 void do_RuntimeCall (RuntimeCall* x); |
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536 void do_MemBar (MemBar* x); |
8860 | 537 void do_RangeCheckPredicate(RangeCheckPredicate* x); |
538 void do_Assert (Assert* x); | |
0 | 539 }; |
540 | |
541 | |
542 // Because of a static contained within (for the purpose of iteration | |
543 // over instructions), it is only valid to have one of these active at | |
544 // a time | |
1584 | 545 class NullCheckEliminator: public ValueVisitor { |
0 | 546 private: |
547 Optimizer* _opt; | |
548 | |
549 ValueSet* _visitable_instructions; // Visit each instruction only once per basic block | |
550 BlockList* _work_list; // Basic blocks to visit | |
551 | |
552 bool visitable(Value x) { | |
553 assert(_visitable_instructions != NULL, "check"); | |
554 return _visitable_instructions->contains(x); | |
555 } | |
556 void mark_visited(Value x) { | |
557 assert(_visitable_instructions != NULL, "check"); | |
558 _visitable_instructions->remove(x); | |
559 } | |
560 void mark_visitable(Value x) { | |
561 assert(_visitable_instructions != NULL, "check"); | |
562 _visitable_instructions->put(x); | |
563 } | |
564 void clear_visitable_state() { | |
565 assert(_visitable_instructions != NULL, "check"); | |
566 _visitable_instructions->clear(); | |
567 } | |
568 | |
569 ValueSet* _set; // current state, propagated to subsequent BlockBegins | |
570 ValueSetList _block_states; // BlockBegin null-check states for all processed blocks | |
571 NullCheckVisitor _visitor; | |
572 NullCheck* _last_explicit_null_check; | |
573 | |
574 bool set_contains(Value x) { assert(_set != NULL, "check"); return _set->contains(x); } | |
575 void set_put (Value x) { assert(_set != NULL, "check"); _set->put(x); } | |
576 void set_remove (Value x) { assert(_set != NULL, "check"); _set->remove(x); } | |
577 | |
578 BlockList* work_list() { return _work_list; } | |
579 | |
580 void iterate_all(); | |
581 void iterate_one(BlockBegin* block); | |
582 | |
583 ValueSet* state() { return _set; } | |
584 void set_state_from (ValueSet* state) { _set->set_from(state); } | |
585 ValueSet* state_for (BlockBegin* block) { return _block_states[block->block_id()]; } | |
586 void set_state_for (BlockBegin* block, ValueSet* stack) { _block_states[block->block_id()] = stack; } | |
587 // Returns true if caused a change in the block's state. | |
588 bool merge_state_for(BlockBegin* block, | |
589 ValueSet* incoming_state); | |
590 | |
591 public: | |
592 // constructor | |
593 NullCheckEliminator(Optimizer* opt) | |
594 : _opt(opt) | |
595 , _set(new ValueSet()) | |
596 , _last_explicit_null_check(NULL) | |
597 , _block_states(BlockBegin::number_of_blocks(), NULL) | |
598 , _work_list(new BlockList()) { | |
599 _visitable_instructions = new ValueSet(); | |
600 _visitor.set_eliminator(this); | |
6843 | 601 CompileLog* log = _opt->ir()->compilation()->log(); |
602 if (log != NULL) | |
603 log->set_context("optimize name='null_check_elimination'"); | |
604 } | |
605 | |
606 ~NullCheckEliminator() { | |
607 CompileLog* log = _opt->ir()->compilation()->log(); | |
608 if (log != NULL) | |
609 log->clear_context(); // skip marker if nothing was printed | |
0 | 610 } |
611 | |
612 Optimizer* opt() { return _opt; } | |
613 IR* ir () { return opt()->ir(); } | |
614 | |
615 // Process a graph | |
616 void iterate(BlockBegin* root); | |
617 | |
1584 | 618 void visit(Value* f); |
619 | |
0 | 620 // In some situations (like NullCheck(x); getfield(x)) the debug |
621 // information from the explicit NullCheck can be used to populate | |
622 // the getfield, even if the two instructions are in different | |
623 // scopes; this allows implicit null checks to be used but the | |
624 // correct exception information to be generated. We must clear the | |
625 // last-traversed NullCheck when we reach a potentially-exception- | |
626 // throwing instruction, as well as in some other cases. | |
627 void set_last_explicit_null_check(NullCheck* check) { _last_explicit_null_check = check; } | |
628 NullCheck* last_explicit_null_check() { return _last_explicit_null_check; } | |
629 Value last_explicit_null_check_obj() { return (_last_explicit_null_check | |
630 ? _last_explicit_null_check->obj() | |
631 : NULL); } | |
632 NullCheck* consume_last_explicit_null_check() { | |
633 _last_explicit_null_check->unpin(Instruction::PinExplicitNullCheck); | |
634 _last_explicit_null_check->set_can_trap(false); | |
635 return _last_explicit_null_check; | |
636 } | |
637 void clear_last_explicit_null_check() { _last_explicit_null_check = NULL; } | |
638 | |
639 // Handlers for relevant instructions | |
640 // (separated out from NullCheckVisitor for clarity) | |
641 | |
642 // The basic contract is that these must leave the instruction in | |
643 // the desired state; must not assume anything about the state of | |
644 // the instruction. We make multiple passes over some basic blocks | |
645 // and the last pass is the only one whose result is valid. | |
646 void handle_AccessField (AccessField* x); | |
647 void handle_ArrayLength (ArrayLength* x); | |
648 void handle_LoadIndexed (LoadIndexed* x); | |
649 void handle_StoreIndexed (StoreIndexed* x); | |
650 void handle_NullCheck (NullCheck* x); | |
651 void handle_Invoke (Invoke* x); | |
652 void handle_NewInstance (NewInstance* x); | |
653 void handle_NewArray (NewArray* x); | |
654 void handle_AccessMonitor (AccessMonitor* x); | |
655 void handle_Intrinsic (Intrinsic* x); | |
656 void handle_ExceptionObject (ExceptionObject* x); | |
657 void handle_Phi (Phi* x); | |
658 }; | |
659 | |
660 | |
661 // NEEDS_CLEANUP | |
662 // There may be other instructions which need to clear the last | |
663 // explicit null check. Anything across which we can not hoist the | |
664 // debug information for a NullCheck instruction must clear it. It | |
665 // might be safer to pattern match "NullCheck ; {AccessField, | |
666 // ArrayLength, LoadIndexed}" but it is more easily structured this way. | |
667 // Should test to see performance hit of clearing it for all handlers | |
668 // with empty bodies below. If it is negligible then we should leave | |
669 // that in for safety, otherwise should think more about it. | |
670 void NullCheckVisitor::do_Phi (Phi* x) { nce()->handle_Phi(x); } | |
671 void NullCheckVisitor::do_Local (Local* x) {} | |
672 void NullCheckVisitor::do_Constant (Constant* x) { /* FIXME: handle object constants */ } | |
673 void NullCheckVisitor::do_LoadField (LoadField* x) { nce()->handle_AccessField(x); } | |
674 void NullCheckVisitor::do_StoreField (StoreField* x) { nce()->handle_AccessField(x); } | |
675 void NullCheckVisitor::do_ArrayLength (ArrayLength* x) { nce()->handle_ArrayLength(x); } | |
676 void NullCheckVisitor::do_LoadIndexed (LoadIndexed* x) { nce()->handle_LoadIndexed(x); } | |
677 void NullCheckVisitor::do_StoreIndexed (StoreIndexed* x) { nce()->handle_StoreIndexed(x); } | |
678 void NullCheckVisitor::do_NegateOp (NegateOp* x) {} | |
679 void NullCheckVisitor::do_ArithmeticOp (ArithmeticOp* x) { if (x->can_trap()) nce()->clear_last_explicit_null_check(); } | |
680 void NullCheckVisitor::do_ShiftOp (ShiftOp* x) {} | |
681 void NullCheckVisitor::do_LogicOp (LogicOp* x) {} | |
682 void NullCheckVisitor::do_CompareOp (CompareOp* x) {} | |
683 void NullCheckVisitor::do_IfOp (IfOp* x) {} | |
684 void NullCheckVisitor::do_Convert (Convert* x) {} | |
685 void NullCheckVisitor::do_NullCheck (NullCheck* x) { nce()->handle_NullCheck(x); } | |
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686 void NullCheckVisitor::do_TypeCast (TypeCast* x) {} |
0 | 687 void NullCheckVisitor::do_Invoke (Invoke* x) { nce()->handle_Invoke(x); } |
688 void NullCheckVisitor::do_NewInstance (NewInstance* x) { nce()->handle_NewInstance(x); } | |
689 void NullCheckVisitor::do_NewTypeArray (NewTypeArray* x) { nce()->handle_NewArray(x); } | |
690 void NullCheckVisitor::do_NewObjectArray (NewObjectArray* x) { nce()->handle_NewArray(x); } | |
691 void NullCheckVisitor::do_NewMultiArray (NewMultiArray* x) { nce()->handle_NewArray(x); } | |
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692 void NullCheckVisitor::do_CheckCast (CheckCast* x) { nce()->clear_last_explicit_null_check(); } |
0 | 693 void NullCheckVisitor::do_InstanceOf (InstanceOf* x) {} |
694 void NullCheckVisitor::do_MonitorEnter (MonitorEnter* x) { nce()->handle_AccessMonitor(x); } | |
695 void NullCheckVisitor::do_MonitorExit (MonitorExit* x) { nce()->handle_AccessMonitor(x); } | |
2446 | 696 void NullCheckVisitor::do_Intrinsic (Intrinsic* x) { nce()->handle_Intrinsic(x); } |
0 | 697 void NullCheckVisitor::do_BlockBegin (BlockBegin* x) {} |
698 void NullCheckVisitor::do_Goto (Goto* x) {} | |
699 void NullCheckVisitor::do_If (If* x) {} | |
700 void NullCheckVisitor::do_IfInstanceOf (IfInstanceOf* x) {} | |
701 void NullCheckVisitor::do_TableSwitch (TableSwitch* x) {} | |
702 void NullCheckVisitor::do_LookupSwitch (LookupSwitch* x) {} | |
703 void NullCheckVisitor::do_Return (Return* x) {} | |
704 void NullCheckVisitor::do_Throw (Throw* x) { nce()->clear_last_explicit_null_check(); } | |
705 void NullCheckVisitor::do_Base (Base* x) {} | |
706 void NullCheckVisitor::do_OsrEntry (OsrEntry* x) {} | |
707 void NullCheckVisitor::do_ExceptionObject(ExceptionObject* x) { nce()->handle_ExceptionObject(x); } | |
708 void NullCheckVisitor::do_RoundFP (RoundFP* x) {} | |
709 void NullCheckVisitor::do_UnsafeGetRaw (UnsafeGetRaw* x) {} | |
710 void NullCheckVisitor::do_UnsafePutRaw (UnsafePutRaw* x) {} | |
711 void NullCheckVisitor::do_UnsafeGetObject(UnsafeGetObject* x) {} | |
712 void NullCheckVisitor::do_UnsafePutObject(UnsafePutObject* x) {} | |
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713 void NullCheckVisitor::do_UnsafeGetAndSetObject(UnsafeGetAndSetObject* x) {} |
0 | 714 void NullCheckVisitor::do_UnsafePrefetchRead (UnsafePrefetchRead* x) {} |
715 void NullCheckVisitor::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {} | |
716 void NullCheckVisitor::do_ProfileCall (ProfileCall* x) { nce()->clear_last_explicit_null_check(); } | |
1783 | 717 void NullCheckVisitor::do_ProfileInvoke (ProfileInvoke* x) {} |
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718 void NullCheckVisitor::do_RuntimeCall (RuntimeCall* x) {} |
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719 void NullCheckVisitor::do_MemBar (MemBar* x) {} |
8860 | 720 void NullCheckVisitor::do_RangeCheckPredicate(RangeCheckPredicate* x) {} |
721 void NullCheckVisitor::do_Assert (Assert* x) {} | |
0 | 722 |
723 | |
1584 | 724 void NullCheckEliminator::visit(Value* p) { |
0 | 725 assert(*p != NULL, "should not find NULL instructions"); |
1584 | 726 if (visitable(*p)) { |
727 mark_visited(*p); | |
728 (*p)->visit(&_visitor); | |
0 | 729 } |
730 } | |
731 | |
732 bool NullCheckEliminator::merge_state_for(BlockBegin* block, ValueSet* incoming_state) { | |
733 ValueSet* state = state_for(block); | |
734 if (state == NULL) { | |
735 state = incoming_state->copy(); | |
736 set_state_for(block, state); | |
737 return true; | |
738 } else { | |
739 bool changed = state->set_intersect(incoming_state); | |
740 if (PrintNullCheckElimination && changed) { | |
741 tty->print_cr("Block %d's null check state changed", block->block_id()); | |
742 } | |
743 return changed; | |
744 } | |
745 } | |
746 | |
747 | |
748 void NullCheckEliminator::iterate_all() { | |
749 while (work_list()->length() > 0) { | |
750 iterate_one(work_list()->pop()); | |
751 } | |
752 } | |
753 | |
754 | |
755 void NullCheckEliminator::iterate_one(BlockBegin* block) { | |
756 clear_visitable_state(); | |
757 // clear out an old explicit null checks | |
758 set_last_explicit_null_check(NULL); | |
759 | |
760 if (PrintNullCheckElimination) { | |
761 tty->print_cr(" ...iterating block %d in null check elimination for %s::%s%s", | |
762 block->block_id(), | |
763 ir()->method()->holder()->name()->as_utf8(), | |
764 ir()->method()->name()->as_utf8(), | |
765 ir()->method()->signature()->as_symbol()->as_utf8()); | |
766 } | |
767 | |
768 // Create new state if none present (only happens at root) | |
769 if (state_for(block) == NULL) { | |
770 ValueSet* tmp_state = new ValueSet(); | |
771 set_state_for(block, tmp_state); | |
772 // Initial state is that local 0 (receiver) is non-null for | |
773 // non-static methods | |
774 ValueStack* stack = block->state(); | |
775 IRScope* scope = stack->scope(); | |
776 ciMethod* method = scope->method(); | |
777 if (!method->is_static()) { | |
778 Local* local0 = stack->local_at(0)->as_Local(); | |
779 assert(local0 != NULL, "must be"); | |
780 assert(local0->type() == objectType, "invalid type of receiver"); | |
781 | |
782 if (local0 != NULL) { | |
783 // Local 0 is used in this scope | |
784 tmp_state->put(local0); | |
785 if (PrintNullCheckElimination) { | |
786 tty->print_cr("Local 0 (value %d) proven non-null upon entry", local0->id()); | |
787 } | |
788 } | |
789 } | |
790 } | |
791 | |
792 // Must copy block's state to avoid mutating it during iteration | |
793 // through the block -- otherwise "not-null" states can accidentally | |
794 // propagate "up" through the block during processing of backward | |
795 // branches and algorithm is incorrect (and does not converge) | |
796 set_state_from(state_for(block)); | |
797 | |
798 // allow visiting of Phis belonging to this block | |
799 for_each_phi_fun(block, phi, | |
800 mark_visitable(phi); | |
801 ); | |
802 | |
803 BlockEnd* e = block->end(); | |
804 assert(e != NULL, "incomplete graph"); | |
805 int i; | |
806 | |
807 // Propagate the state before this block into the exception | |
808 // handlers. They aren't true successors since we aren't guaranteed | |
809 // to execute the whole block before executing them. Also putting | |
810 // them on first seems to help reduce the amount of iteration to | |
811 // reach a fixed point. | |
812 for (i = 0; i < block->number_of_exception_handlers(); i++) { | |
813 BlockBegin* next = block->exception_handler_at(i); | |
814 if (merge_state_for(next, state())) { | |
815 if (!work_list()->contains(next)) { | |
816 work_list()->push(next); | |
817 } | |
818 } | |
819 } | |
820 | |
821 // Iterate through block, updating state. | |
822 for (Instruction* instr = block; instr != NULL; instr = instr->next()) { | |
823 // Mark instructions in this block as visitable as they are seen | |
824 // in the instruction list. This keeps the iteration from | |
825 // visiting instructions which are references in other blocks or | |
826 // visiting instructions more than once. | |
827 mark_visitable(instr); | |
1819 | 828 if (instr->is_pinned() || instr->can_trap() || (instr->as_NullCheck() != NULL)) { |
0 | 829 mark_visited(instr); |
1584 | 830 instr->input_values_do(this); |
0 | 831 instr->visit(&_visitor); |
832 } | |
833 } | |
834 | |
835 // Propagate state to successors if necessary | |
836 for (i = 0; i < e->number_of_sux(); i++) { | |
837 BlockBegin* next = e->sux_at(i); | |
838 if (merge_state_for(next, state())) { | |
839 if (!work_list()->contains(next)) { | |
840 work_list()->push(next); | |
841 } | |
842 } | |
843 } | |
844 } | |
845 | |
846 | |
847 void NullCheckEliminator::iterate(BlockBegin* block) { | |
848 work_list()->push(block); | |
849 iterate_all(); | |
850 } | |
851 | |
852 void NullCheckEliminator::handle_AccessField(AccessField* x) { | |
853 if (x->is_static()) { | |
854 if (x->as_LoadField() != NULL) { | |
855 // If the field is a non-null static final object field (as is | |
856 // often the case for sun.misc.Unsafe), put this LoadField into | |
857 // the non-null map | |
858 ciField* field = x->field(); | |
859 if (field->is_constant()) { | |
860 ciConstant field_val = field->constant_value(); | |
861 BasicType field_type = field_val.basic_type(); | |
862 if (field_type == T_OBJECT || field_type == T_ARRAY) { | |
863 ciObject* obj_val = field_val.as_object(); | |
864 if (!obj_val->is_null_object()) { | |
865 if (PrintNullCheckElimination) { | |
866 tty->print_cr("AccessField %d proven non-null by static final non-null oop check", | |
867 x->id()); | |
868 } | |
869 set_put(x); | |
870 } | |
871 } | |
872 } | |
873 } | |
874 // Be conservative | |
875 clear_last_explicit_null_check(); | |
876 return; | |
877 } | |
878 | |
879 Value obj = x->obj(); | |
880 if (set_contains(obj)) { | |
881 // Value is non-null => update AccessField | |
882 if (last_explicit_null_check_obj() == obj && !x->needs_patching()) { | |
883 x->set_explicit_null_check(consume_last_explicit_null_check()); | |
884 x->set_needs_null_check(true); | |
885 if (PrintNullCheckElimination) { | |
886 tty->print_cr("Folded NullCheck %d into AccessField %d's null check for value %d", | |
887 x->explicit_null_check()->id(), x->id(), obj->id()); | |
888 } | |
889 } else { | |
890 x->set_explicit_null_check(NULL); | |
891 x->set_needs_null_check(false); | |
892 if (PrintNullCheckElimination) { | |
893 tty->print_cr("Eliminated AccessField %d's null check for value %d", x->id(), obj->id()); | |
894 } | |
895 } | |
896 } else { | |
897 set_put(obj); | |
898 if (PrintNullCheckElimination) { | |
899 tty->print_cr("AccessField %d of value %d proves value to be non-null", x->id(), obj->id()); | |
900 } | |
901 // Ensure previous passes do not cause wrong state | |
902 x->set_needs_null_check(true); | |
903 x->set_explicit_null_check(NULL); | |
904 } | |
905 clear_last_explicit_null_check(); | |
906 } | |
907 | |
908 | |
909 void NullCheckEliminator::handle_ArrayLength(ArrayLength* x) { | |
910 Value array = x->array(); | |
911 if (set_contains(array)) { | |
912 // Value is non-null => update AccessArray | |
913 if (last_explicit_null_check_obj() == array) { | |
914 x->set_explicit_null_check(consume_last_explicit_null_check()); | |
915 x->set_needs_null_check(true); | |
916 if (PrintNullCheckElimination) { | |
917 tty->print_cr("Folded NullCheck %d into ArrayLength %d's null check for value %d", | |
918 x->explicit_null_check()->id(), x->id(), array->id()); | |
919 } | |
920 } else { | |
921 x->set_explicit_null_check(NULL); | |
922 x->set_needs_null_check(false); | |
923 if (PrintNullCheckElimination) { | |
924 tty->print_cr("Eliminated ArrayLength %d's null check for value %d", x->id(), array->id()); | |
925 } | |
926 } | |
927 } else { | |
928 set_put(array); | |
929 if (PrintNullCheckElimination) { | |
930 tty->print_cr("ArrayLength %d of value %d proves value to be non-null", x->id(), array->id()); | |
931 } | |
932 // Ensure previous passes do not cause wrong state | |
933 x->set_needs_null_check(true); | |
934 x->set_explicit_null_check(NULL); | |
935 } | |
936 clear_last_explicit_null_check(); | |
937 } | |
938 | |
939 | |
940 void NullCheckEliminator::handle_LoadIndexed(LoadIndexed* x) { | |
941 Value array = x->array(); | |
942 if (set_contains(array)) { | |
943 // Value is non-null => update AccessArray | |
944 if (last_explicit_null_check_obj() == array) { | |
945 x->set_explicit_null_check(consume_last_explicit_null_check()); | |
946 x->set_needs_null_check(true); | |
947 if (PrintNullCheckElimination) { | |
948 tty->print_cr("Folded NullCheck %d into LoadIndexed %d's null check for value %d", | |
949 x->explicit_null_check()->id(), x->id(), array->id()); | |
950 } | |
951 } else { | |
952 x->set_explicit_null_check(NULL); | |
953 x->set_needs_null_check(false); | |
954 if (PrintNullCheckElimination) { | |
955 tty->print_cr("Eliminated LoadIndexed %d's null check for value %d", x->id(), array->id()); | |
956 } | |
957 } | |
958 } else { | |
959 set_put(array); | |
960 if (PrintNullCheckElimination) { | |
961 tty->print_cr("LoadIndexed %d of value %d proves value to be non-null", x->id(), array->id()); | |
962 } | |
963 // Ensure previous passes do not cause wrong state | |
964 x->set_needs_null_check(true); | |
965 x->set_explicit_null_check(NULL); | |
966 } | |
967 clear_last_explicit_null_check(); | |
968 } | |
969 | |
970 | |
971 void NullCheckEliminator::handle_StoreIndexed(StoreIndexed* x) { | |
972 Value array = x->array(); | |
973 if (set_contains(array)) { | |
974 // Value is non-null => update AccessArray | |
975 if (PrintNullCheckElimination) { | |
976 tty->print_cr("Eliminated StoreIndexed %d's null check for value %d", x->id(), array->id()); | |
977 } | |
978 x->set_needs_null_check(false); | |
979 } else { | |
980 set_put(array); | |
981 if (PrintNullCheckElimination) { | |
982 tty->print_cr("StoreIndexed %d of value %d proves value to be non-null", x->id(), array->id()); | |
983 } | |
984 // Ensure previous passes do not cause wrong state | |
985 x->set_needs_null_check(true); | |
986 } | |
987 clear_last_explicit_null_check(); | |
988 } | |
989 | |
990 | |
991 void NullCheckEliminator::handle_NullCheck(NullCheck* x) { | |
992 Value obj = x->obj(); | |
993 if (set_contains(obj)) { | |
994 // Already proven to be non-null => this NullCheck is useless | |
995 if (PrintNullCheckElimination) { | |
996 tty->print_cr("Eliminated NullCheck %d for value %d", x->id(), obj->id()); | |
997 } | |
998 // Don't unpin since that may shrink obj's live range and make it unavailable for debug info. | |
999 // The code generator won't emit LIR for a NullCheck that cannot trap. | |
1000 x->set_can_trap(false); | |
1001 } else { | |
1002 // May be null => add to map and set last explicit NullCheck | |
1003 x->set_can_trap(true); | |
1004 // make sure it's pinned if it can trap | |
1005 x->pin(Instruction::PinExplicitNullCheck); | |
1006 set_put(obj); | |
1007 set_last_explicit_null_check(x); | |
1008 if (PrintNullCheckElimination) { | |
1009 tty->print_cr("NullCheck %d of value %d proves value to be non-null", x->id(), obj->id()); | |
1010 } | |
1011 } | |
1012 } | |
1013 | |
1014 | |
1015 void NullCheckEliminator::handle_Invoke(Invoke* x) { | |
1016 if (!x->has_receiver()) { | |
1017 // Be conservative | |
1018 clear_last_explicit_null_check(); | |
1019 return; | |
1020 } | |
1021 | |
1022 Value recv = x->receiver(); | |
1023 if (!set_contains(recv)) { | |
1024 set_put(recv); | |
1025 if (PrintNullCheckElimination) { | |
1026 tty->print_cr("Invoke %d of value %d proves value to be non-null", x->id(), recv->id()); | |
1027 } | |
1028 } | |
1029 clear_last_explicit_null_check(); | |
1030 } | |
1031 | |
1032 | |
1033 void NullCheckEliminator::handle_NewInstance(NewInstance* x) { | |
1034 set_put(x); | |
1035 if (PrintNullCheckElimination) { | |
1036 tty->print_cr("NewInstance %d is non-null", x->id()); | |
1037 } | |
1038 } | |
1039 | |
1040 | |
1041 void NullCheckEliminator::handle_NewArray(NewArray* x) { | |
1042 set_put(x); | |
1043 if (PrintNullCheckElimination) { | |
1044 tty->print_cr("NewArray %d is non-null", x->id()); | |
1045 } | |
1046 } | |
1047 | |
1048 | |
1049 void NullCheckEliminator::handle_ExceptionObject(ExceptionObject* x) { | |
1050 set_put(x); | |
1051 if (PrintNullCheckElimination) { | |
1052 tty->print_cr("ExceptionObject %d is non-null", x->id()); | |
1053 } | |
1054 } | |
1055 | |
1056 | |
1057 void NullCheckEliminator::handle_AccessMonitor(AccessMonitor* x) { | |
1058 Value obj = x->obj(); | |
1059 if (set_contains(obj)) { | |
1060 // Value is non-null => update AccessMonitor | |
1061 if (PrintNullCheckElimination) { | |
1062 tty->print_cr("Eliminated AccessMonitor %d's null check for value %d", x->id(), obj->id()); | |
1063 } | |
1064 x->set_needs_null_check(false); | |
1065 } else { | |
1066 set_put(obj); | |
1067 if (PrintNullCheckElimination) { | |
1068 tty->print_cr("AccessMonitor %d of value %d proves value to be non-null", x->id(), obj->id()); | |
1069 } | |
1070 // Ensure previous passes do not cause wrong state | |
1071 x->set_needs_null_check(true); | |
1072 } | |
1073 clear_last_explicit_null_check(); | |
1074 } | |
1075 | |
1076 | |
1077 void NullCheckEliminator::handle_Intrinsic(Intrinsic* x) { | |
1078 if (!x->has_receiver()) { | |
2446 | 1079 if (x->id() == vmIntrinsics::_arraycopy) { |
1080 for (int i = 0; i < x->number_of_arguments(); i++) { | |
1081 x->set_arg_needs_null_check(i, !set_contains(x->argument_at(i))); | |
1082 } | |
1083 } | |
1084 | |
0 | 1085 // Be conservative |
1086 clear_last_explicit_null_check(); | |
1087 return; | |
1088 } | |
1089 | |
1090 Value recv = x->receiver(); | |
1091 if (set_contains(recv)) { | |
1092 // Value is non-null => update Intrinsic | |
1093 if (PrintNullCheckElimination) { | |
1094 tty->print_cr("Eliminated Intrinsic %d's null check for value %d", x->id(), recv->id()); | |
1095 } | |
1096 x->set_needs_null_check(false); | |
1097 } else { | |
1098 set_put(recv); | |
1099 if (PrintNullCheckElimination) { | |
1100 tty->print_cr("Intrinsic %d of value %d proves value to be non-null", x->id(), recv->id()); | |
1101 } | |
1102 // Ensure previous passes do not cause wrong state | |
1103 x->set_needs_null_check(true); | |
1104 } | |
1105 clear_last_explicit_null_check(); | |
1106 } | |
1107 | |
1108 | |
1109 void NullCheckEliminator::handle_Phi(Phi* x) { | |
1110 int i; | |
1111 bool all_non_null = true; | |
1112 if (x->is_illegal()) { | |
1113 all_non_null = false; | |
1114 } else { | |
1115 for (i = 0; i < x->operand_count(); i++) { | |
1116 Value input = x->operand_at(i); | |
1117 if (!set_contains(input)) { | |
1118 all_non_null = false; | |
1119 } | |
1120 } | |
1121 } | |
1122 | |
1123 if (all_non_null) { | |
1124 // Value is non-null => update Phi | |
1125 if (PrintNullCheckElimination) { | |
1126 tty->print_cr("Eliminated Phi %d's null check for phifun because all inputs are non-null", x->id()); | |
1127 } | |
1128 x->set_needs_null_check(false); | |
1129 } else if (set_contains(x)) { | |
1130 set_remove(x); | |
1131 } | |
1132 } | |
1133 | |
1134 | |
1135 void Optimizer::eliminate_null_checks() { | |
1136 ResourceMark rm; | |
1137 | |
1138 NullCheckEliminator nce(this); | |
1139 | |
1140 if (PrintNullCheckElimination) { | |
1141 tty->print_cr("Starting null check elimination for method %s::%s%s", | |
1142 ir()->method()->holder()->name()->as_utf8(), | |
1143 ir()->method()->name()->as_utf8(), | |
1144 ir()->method()->signature()->as_symbol()->as_utf8()); | |
1145 } | |
1146 | |
1147 // Apply to graph | |
1148 nce.iterate(ir()->start()); | |
1149 | |
1150 // walk over the graph looking for exception | |
1151 // handlers and iterate over them as well | |
1152 int nblocks = BlockBegin::number_of_blocks(); | |
1153 BlockList blocks(nblocks); | |
1154 boolArray visited_block(nblocks, false); | |
1155 | |
1156 blocks.push(ir()->start()); | |
1157 visited_block[ir()->start()->block_id()] = true; | |
1158 for (int i = 0; i < blocks.length(); i++) { | |
1159 BlockBegin* b = blocks[i]; | |
1160 // exception handlers need to be treated as additional roots | |
1161 for (int e = b->number_of_exception_handlers(); e-- > 0; ) { | |
1162 BlockBegin* excp = b->exception_handler_at(e); | |
1163 int id = excp->block_id(); | |
1164 if (!visited_block[id]) { | |
1165 blocks.push(excp); | |
1166 visited_block[id] = true; | |
1167 nce.iterate(excp); | |
1168 } | |
1169 } | |
1170 // traverse successors | |
1171 BlockEnd *end = b->end(); | |
1172 for (int s = end->number_of_sux(); s-- > 0; ) { | |
1173 BlockBegin* next = end->sux_at(s); | |
1174 int id = next->block_id(); | |
1175 if (!visited_block[id]) { | |
1176 blocks.push(next); | |
1177 visited_block[id] = true; | |
1178 } | |
1179 } | |
1180 } | |
1181 | |
1182 | |
1183 if (PrintNullCheckElimination) { | |
1184 tty->print_cr("Done with null check elimination for method %s::%s%s", | |
1185 ir()->method()->holder()->name()->as_utf8(), | |
1186 ir()->method()->name()->as_utf8(), | |
1187 ir()->method()->signature()->as_symbol()->as_utf8()); | |
1188 } | |
1189 } |