1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "compiler/compileLog.hpp"
27 #include "gc/g1/g1SATBCardTableModRefBS.hpp"
28 #include "gc/g1/heapRegion.hpp"
29 #include "gc/shared/barrierSet.hpp"
30 #include "gc/shared/cardTableModRefBS.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "opto/addnode.hpp"
33 #include "opto/castnode.hpp"
34 #include "opto/convertnode.hpp"
35 #include "opto/graphKit.hpp"
36 #include "opto/idealKit.hpp"
37 #include "opto/intrinsicnode.hpp"
38 #include "opto/locknode.hpp"
39 #include "opto/machnode.hpp"
40 #include "opto/opaquenode.hpp"
41 #include "opto/parse.hpp"
42 #include "opto/rootnode.hpp"
43 #include "opto/runtime.hpp"
44 #include "runtime/deoptimization.hpp"
45 #include "runtime/sharedRuntime.hpp"
46
47 //----------------------------GraphKit-----------------------------------------
48 // Main utility constructor.
49 GraphKit::GraphKit(JVMState* jvms)
50 : Phase(Phase::Parser),
51 _env(C->env()),
52 _gvn(*C->initial_gvn())
53 {
54 _exceptions = jvms->map()->next_exception();
55 if (_exceptions != NULL) jvms->map()->set_next_exception(NULL);
56 set_jvms(jvms);
57 }
58
59 // Private constructor for parser.
60 GraphKit::GraphKit()
61 : Phase(Phase::Parser),
62 _env(C->env()),
63 _gvn(*C->initial_gvn())
64 {
65 _exceptions = NULL;
66 set_map(NULL);
67 debug_only(_sp = -99);
68 debug_only(set_bci(-99));
69 }
70
71
72
73 //---------------------------clean_stack---------------------------------------
74 // Clear away rubbish from the stack area of the JVM state.
75 // This destroys any arguments that may be waiting on the stack.
76 void GraphKit::clean_stack(int from_sp) {
77 SafePointNode* map = this->map();
78 JVMState* jvms = this->jvms();
79 int stk_size = jvms->stk_size();
80 int stkoff = jvms->stkoff();
81 Node* top = this->top();
82 for (int i = from_sp; i < stk_size; i++) {
83 if (map->in(stkoff + i) != top) {
84 map->set_req(stkoff + i, top);
85 }
86 }
87 }
88
89
90 //--------------------------------sync_jvms-----------------------------------
91 // Make sure our current jvms agrees with our parse state.
92 JVMState* GraphKit::sync_jvms() const {
93 JVMState* jvms = this->jvms();
94 jvms->set_bci(bci()); // Record the new bci in the JVMState
95 jvms->set_sp(sp()); // Record the new sp in the JVMState
96 assert(jvms_in_sync(), "jvms is now in sync");
97 return jvms;
98 }
99
100 //--------------------------------sync_jvms_for_reexecute---------------------
101 // Make sure our current jvms agrees with our parse state. This version
102 // uses the reexecute_sp for reexecuting bytecodes.
103 JVMState* GraphKit::sync_jvms_for_reexecute() {
104 JVMState* jvms = this->jvms();
105 jvms->set_bci(bci()); // Record the new bci in the JVMState
106 jvms->set_sp(reexecute_sp()); // Record the new sp in the JVMState
107 return jvms;
108 }
109
110 #ifdef ASSERT
111 bool GraphKit::jvms_in_sync() const {
112 Parse* parse = is_Parse();
113 if (parse == NULL) {
114 if (bci() != jvms()->bci()) return false;
115 if (sp() != (int)jvms()->sp()) return false;
116 return true;
117 }
118 if (jvms()->method() != parse->method()) return false;
119 if (jvms()->bci() != parse->bci()) return false;
120 int jvms_sp = jvms()->sp();
121 if (jvms_sp != parse->sp()) return false;
122 int jvms_depth = jvms()->depth();
123 if (jvms_depth != parse->depth()) return false;
124 return true;
125 }
126
127 // Local helper checks for special internal merge points
128 // used to accumulate and merge exception states.
129 // They are marked by the region's in(0) edge being the map itself.
130 // Such merge points must never "escape" into the parser at large,
131 // until they have been handed to gvn.transform.
132 static bool is_hidden_merge(Node* reg) {
133 if (reg == NULL) return false;
134 if (reg->is_Phi()) {
135 reg = reg->in(0);
136 if (reg == NULL) return false;
137 }
138 return reg->is_Region() && reg->in(0) != NULL && reg->in(0)->is_Root();
139 }
140
141 void GraphKit::verify_map() const {
142 if (map() == NULL) return; // null map is OK
143 assert(map()->req() <= jvms()->endoff(), "no extra garbage on map");
144 assert(!map()->has_exceptions(), "call add_exception_states_from 1st");
145 assert(!is_hidden_merge(control()), "call use_exception_state, not set_map");
146 }
147
148 void GraphKit::verify_exception_state(SafePointNode* ex_map) {
149 assert(ex_map->next_exception() == NULL, "not already part of a chain");
150 assert(has_saved_ex_oop(ex_map), "every exception state has an ex_oop");
151 }
152 #endif
153
154 //---------------------------stop_and_kill_map---------------------------------
155 // Set _map to NULL, signalling a stop to further bytecode execution.
156 // First smash the current map's control to a constant, to mark it dead.
157 void GraphKit::stop_and_kill_map() {
158 SafePointNode* dead_map = stop();
159 if (dead_map != NULL) {
160 dead_map->disconnect_inputs(NULL, C); // Mark the map as killed.
161 assert(dead_map->is_killed(), "must be so marked");
162 }
163 }
164
165
166 //--------------------------------stopped--------------------------------------
167 // Tell if _map is NULL, or control is top.
168 bool GraphKit::stopped() {
169 if (map() == NULL) return true;
170 else if (control() == top()) return true;
171 else return false;
172 }
173
174
175 //-----------------------------has_ex_handler----------------------------------
176 // Tell if this method or any caller method has exception handlers.
177 bool GraphKit::has_ex_handler() {
178 for (JVMState* jvmsp = jvms(); jvmsp != NULL; jvmsp = jvmsp->caller()) {
179 if (jvmsp->has_method() && jvmsp->method()->has_exception_handlers()) {
180 return true;
181 }
182 }
183 return false;
184 }
185
186 //------------------------------save_ex_oop------------------------------------
187 // Save an exception without blowing stack contents or other JVM state.
188 void GraphKit::set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop) {
189 assert(!has_saved_ex_oop(ex_map), "clear ex-oop before setting again");
190 ex_map->add_req(ex_oop);
191 debug_only(verify_exception_state(ex_map));
192 }
193
194 inline static Node* common_saved_ex_oop(SafePointNode* ex_map, bool clear_it) {
195 assert(GraphKit::has_saved_ex_oop(ex_map), "ex_oop must be there");
196 Node* ex_oop = ex_map->in(ex_map->req()-1);
197 if (clear_it) ex_map->del_req(ex_map->req()-1);
198 return ex_oop;
199 }
200
201 //-----------------------------saved_ex_oop------------------------------------
202 // Recover a saved exception from its map.
203 Node* GraphKit::saved_ex_oop(SafePointNode* ex_map) {
204 return common_saved_ex_oop(ex_map, false);
205 }
206
207 //--------------------------clear_saved_ex_oop---------------------------------
208 // Erase a previously saved exception from its map.
209 Node* GraphKit::clear_saved_ex_oop(SafePointNode* ex_map) {
210 return common_saved_ex_oop(ex_map, true);
211 }
212
213 #ifdef ASSERT
214 //---------------------------has_saved_ex_oop----------------------------------
215 // Erase a previously saved exception from its map.
216 bool GraphKit::has_saved_ex_oop(SafePointNode* ex_map) {
217 return ex_map->req() == ex_map->jvms()->endoff()+1;
218 }
219 #endif
220
221 //-------------------------make_exception_state--------------------------------
222 // Turn the current JVM state into an exception state, appending the ex_oop.
223 SafePointNode* GraphKit::make_exception_state(Node* ex_oop) {
224 sync_jvms();
225 SafePointNode* ex_map = stop(); // do not manipulate this map any more
226 set_saved_ex_oop(ex_map, ex_oop);
227 return ex_map;
228 }
229
230
231 //--------------------------add_exception_state--------------------------------
232 // Add an exception to my list of exceptions.
233 void GraphKit::add_exception_state(SafePointNode* ex_map) {
234 if (ex_map == NULL || ex_map->control() == top()) {
235 return;
236 }
237 #ifdef ASSERT
238 verify_exception_state(ex_map);
239 if (has_exceptions()) {
240 assert(ex_map->jvms()->same_calls_as(_exceptions->jvms()), "all collected exceptions must come from the same place");
241 }
242 #endif
243
244 // If there is already an exception of exactly this type, merge with it.
245 // In particular, null-checks and other low-level exceptions common up here.
246 Node* ex_oop = saved_ex_oop(ex_map);
247 const Type* ex_type = _gvn.type(ex_oop);
248 if (ex_oop == top()) {
249 // No action needed.
250 return;
251 }
252 assert(ex_type->isa_instptr(), "exception must be an instance");
253 for (SafePointNode* e2 = _exceptions; e2 != NULL; e2 = e2->next_exception()) {
254 const Type* ex_type2 = _gvn.type(saved_ex_oop(e2));
255 // We check sp also because call bytecodes can generate exceptions
256 // both before and after arguments are popped!
257 if (ex_type2 == ex_type
258 && e2->_jvms->sp() == ex_map->_jvms->sp()) {
259 combine_exception_states(ex_map, e2);
260 return;
261 }
262 }
263
264 // No pre-existing exception of the same type. Chain it on the list.
265 push_exception_state(ex_map);
266 }
267
268 //-----------------------add_exception_states_from-----------------------------
269 void GraphKit::add_exception_states_from(JVMState* jvms) {
270 SafePointNode* ex_map = jvms->map()->next_exception();
271 if (ex_map != NULL) {
272 jvms->map()->set_next_exception(NULL);
273 for (SafePointNode* next_map; ex_map != NULL; ex_map = next_map) {
274 next_map = ex_map->next_exception();
275 ex_map->set_next_exception(NULL);
276 add_exception_state(ex_map);
277 }
278 }
279 }
280
281 //-----------------------transfer_exceptions_into_jvms-------------------------
282 JVMState* GraphKit::transfer_exceptions_into_jvms() {
283 if (map() == NULL) {
284 // We need a JVMS to carry the exceptions, but the map has gone away.
285 // Create a scratch JVMS, cloned from any of the exception states...
286 if (has_exceptions()) {
287 _map = _exceptions;
288 _map = clone_map();
289 _map->set_next_exception(NULL);
290 clear_saved_ex_oop(_map);
291 debug_only(verify_map());
292 } else {
293 // ...or created from scratch
294 JVMState* jvms = new (C) JVMState(_method, NULL);
295 jvms->set_bci(_bci);
296 jvms->set_sp(_sp);
297 jvms->set_map(new SafePointNode(TypeFunc::Parms, jvms));
298 set_jvms(jvms);
299 for (uint i = 0; i < map()->req(); i++) map()->init_req(i, top());
300 set_all_memory(top());
301 while (map()->req() < jvms->endoff()) map()->add_req(top());
302 }
303 // (This is a kludge, in case you didn't notice.)
304 set_control(top());
305 }
306 JVMState* jvms = sync_jvms();
307 assert(!jvms->map()->has_exceptions(), "no exceptions on this map yet");
308 jvms->map()->set_next_exception(_exceptions);
309 _exceptions = NULL; // done with this set of exceptions
310 return jvms;
311 }
312
313 static inline void add_n_reqs(Node* dstphi, Node* srcphi) {
314 assert(is_hidden_merge(dstphi), "must be a special merge node");
315 assert(is_hidden_merge(srcphi), "must be a special merge node");
316 uint limit = srcphi->req();
317 for (uint i = PhiNode::Input; i < limit; i++) {
318 dstphi->add_req(srcphi->in(i));
319 }
320 }
321 static inline void add_one_req(Node* dstphi, Node* src) {
322 assert(is_hidden_merge(dstphi), "must be a special merge node");
323 assert(!is_hidden_merge(src), "must not be a special merge node");
324 dstphi->add_req(src);
325 }
326
327 //-----------------------combine_exception_states------------------------------
328 // This helper function combines exception states by building phis on a
329 // specially marked state-merging region. These regions and phis are
330 // untransformed, and can build up gradually. The region is marked by
331 // having a control input of its exception map, rather than NULL. Such
332 // regions do not appear except in this function, and in use_exception_state.
333 void GraphKit::combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map) {
334 if (failing()) return; // dying anyway...
335 JVMState* ex_jvms = ex_map->_jvms;
336 assert(ex_jvms->same_calls_as(phi_map->_jvms), "consistent call chains");
337 assert(ex_jvms->stkoff() == phi_map->_jvms->stkoff(), "matching locals");
338 assert(ex_jvms->sp() == phi_map->_jvms->sp(), "matching stack sizes");
339 assert(ex_jvms->monoff() == phi_map->_jvms->monoff(), "matching JVMS");
340 assert(ex_jvms->scloff() == phi_map->_jvms->scloff(), "matching scalar replaced objects");
341 assert(ex_map->req() == phi_map->req(), "matching maps");
342 uint tos = ex_jvms->stkoff() + ex_jvms->sp();
343 Node* hidden_merge_mark = root();
344 Node* region = phi_map->control();
345 MergeMemNode* phi_mem = phi_map->merged_memory();
346 MergeMemNode* ex_mem = ex_map->merged_memory();
347 if (region->in(0) != hidden_merge_mark) {
348 // The control input is not (yet) a specially-marked region in phi_map.
349 // Make it so, and build some phis.
350 region = new RegionNode(2);
351 _gvn.set_type(region, Type::CONTROL);
352 region->set_req(0, hidden_merge_mark); // marks an internal ex-state
353 region->init_req(1, phi_map->control());
354 phi_map->set_control(region);
355 Node* io_phi = PhiNode::make(region, phi_map->i_o(), Type::ABIO);
356 record_for_igvn(io_phi);
357 _gvn.set_type(io_phi, Type::ABIO);
358 phi_map->set_i_o(io_phi);
359 for (MergeMemStream mms(phi_mem); mms.next_non_empty(); ) {
360 Node* m = mms.memory();
361 Node* m_phi = PhiNode::make(region, m, Type::MEMORY, mms.adr_type(C));
362 record_for_igvn(m_phi);
363 _gvn.set_type(m_phi, Type::MEMORY);
364 mms.set_memory(m_phi);
365 }
366 }
367
368 // Either or both of phi_map and ex_map might already be converted into phis.
369 Node* ex_control = ex_map->control();
370 // if there is special marking on ex_map also, we add multiple edges from src
371 bool add_multiple = (ex_control->in(0) == hidden_merge_mark);
372 // how wide was the destination phi_map, originally?
373 uint orig_width = region->req();
374
375 if (add_multiple) {
376 add_n_reqs(region, ex_control);
377 add_n_reqs(phi_map->i_o(), ex_map->i_o());
378 } else {
379 // ex_map has no merges, so we just add single edges everywhere
380 add_one_req(region, ex_control);
381 add_one_req(phi_map->i_o(), ex_map->i_o());
382 }
383 for (MergeMemStream mms(phi_mem, ex_mem); mms.next_non_empty2(); ) {
384 if (mms.is_empty()) {
385 // get a copy of the base memory, and patch some inputs into it
386 const TypePtr* adr_type = mms.adr_type(C);
387 Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
388 assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
389 mms.set_memory(phi);
390 // Prepare to append interesting stuff onto the newly sliced phi:
391 while (phi->req() > orig_width) phi->del_req(phi->req()-1);
392 }
393 // Append stuff from ex_map:
394 if (add_multiple) {
395 add_n_reqs(mms.memory(), mms.memory2());
396 } else {
397 add_one_req(mms.memory(), mms.memory2());
398 }
399 }
400 uint limit = ex_map->req();
401 for (uint i = TypeFunc::Parms; i < limit; i++) {
402 // Skip everything in the JVMS after tos. (The ex_oop follows.)
403 if (i == tos) i = ex_jvms->monoff();
404 Node* src = ex_map->in(i);
405 Node* dst = phi_map->in(i);
406 if (src != dst) {
407 PhiNode* phi;
408 if (dst->in(0) != region) {
409 dst = phi = PhiNode::make(region, dst, _gvn.type(dst));
410 record_for_igvn(phi);
411 _gvn.set_type(phi, phi->type());
412 phi_map->set_req(i, dst);
413 // Prepare to append interesting stuff onto the new phi:
414 while (dst->req() > orig_width) dst->del_req(dst->req()-1);
415 } else {
416 assert(dst->is_Phi(), "nobody else uses a hidden region");
417 phi = dst->as_Phi();
418 }
419 if (add_multiple && src->in(0) == ex_control) {
420 // Both are phis.
421 add_n_reqs(dst, src);
422 } else {
423 while (dst->req() < region->req()) add_one_req(dst, src);
424 }
425 const Type* srctype = _gvn.type(src);
426 if (phi->type() != srctype) {
427 const Type* dsttype = phi->type()->meet_speculative(srctype);
428 if (phi->type() != dsttype) {
429 phi->set_type(dsttype);
430 _gvn.set_type(phi, dsttype);
431 }
432 }
433 }
434 }
435 phi_map->merge_replaced_nodes_with(ex_map);
436 }
437
438 //--------------------------use_exception_state--------------------------------
439 Node* GraphKit::use_exception_state(SafePointNode* phi_map) {
440 if (failing()) { stop(); return top(); }
441 Node* region = phi_map->control();
442 Node* hidden_merge_mark = root();
443 assert(phi_map->jvms()->map() == phi_map, "sanity: 1-1 relation");
444 Node* ex_oop = clear_saved_ex_oop(phi_map);
445 if (region->in(0) == hidden_merge_mark) {
446 // Special marking for internal ex-states. Process the phis now.
447 region->set_req(0, region); // now it's an ordinary region
448 set_jvms(phi_map->jvms()); // ...so now we can use it as a map
449 // Note: Setting the jvms also sets the bci and sp.
450 set_control(_gvn.transform(region));
451 uint tos = jvms()->stkoff() + sp();
452 for (uint i = 1; i < tos; i++) {
453 Node* x = phi_map->in(i);
454 if (x->in(0) == region) {
455 assert(x->is_Phi(), "expected a special phi");
456 phi_map->set_req(i, _gvn.transform(x));
457 }
458 }
459 for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
460 Node* x = mms.memory();
461 if (x->in(0) == region) {
462 assert(x->is_Phi(), "nobody else uses a hidden region");
463 mms.set_memory(_gvn.transform(x));
464 }
465 }
466 if (ex_oop->in(0) == region) {
467 assert(ex_oop->is_Phi(), "expected a special phi");
468 ex_oop = _gvn.transform(ex_oop);
469 }
470 } else {
471 set_jvms(phi_map->jvms());
472 }
473
474 assert(!is_hidden_merge(phi_map->control()), "hidden ex. states cleared");
475 assert(!is_hidden_merge(phi_map->i_o()), "hidden ex. states cleared");
476 return ex_oop;
477 }
478
479 //---------------------------------java_bc-------------------------------------
480 Bytecodes::Code GraphKit::java_bc() const {
481 ciMethod* method = this->method();
482 int bci = this->bci();
483 if (method != NULL && bci != InvocationEntryBci)
484 return method->java_code_at_bci(bci);
485 else
486 return Bytecodes::_illegal;
487 }
488
489 void GraphKit::uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
490 bool must_throw) {
491 // if the exception capability is set, then we will generate code
492 // to check the JavaThread.should_post_on_exceptions flag to see
493 // if we actually need to report exception events (for this
494 // thread). If we don't need to report exception events, we will
495 // take the normal fast path provided by add_exception_events. If
496 // exception event reporting is enabled for this thread, we will
497 // take the uncommon_trap in the BuildCutout below.
498
499 // first must access the should_post_on_exceptions_flag in this thread's JavaThread
500 Node* jthread = _gvn.transform(new ThreadLocalNode());
501 Node* adr = basic_plus_adr(top(), jthread, in_bytes(JavaThread::should_post_on_exceptions_flag_offset()));
502 Node* should_post_flag = make_load(control(), adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw, MemNode::unordered);
503
504 // Test the should_post_on_exceptions_flag vs. 0
505 Node* chk = _gvn.transform( new CmpINode(should_post_flag, intcon(0)) );
506 Node* tst = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
507
508 // Branch to slow_path if should_post_on_exceptions_flag was true
509 { BuildCutout unless(this, tst, PROB_MAX);
510 // Do not try anything fancy if we're notifying the VM on every throw.
511 // Cf. case Bytecodes::_athrow in parse2.cpp.
512 uncommon_trap(reason, Deoptimization::Action_none,
513 (ciKlass*)NULL, (char*)NULL, must_throw);
514 }
515
516 }
517
518 //------------------------------builtin_throw----------------------------------
519 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
520 bool must_throw = true;
521
522 if (env()->jvmti_can_post_on_exceptions()) {
523 // check if we must post exception events, take uncommon trap if so
524 uncommon_trap_if_should_post_on_exceptions(reason, must_throw);
525 // here if should_post_on_exceptions is false
526 // continue on with the normal codegen
527 }
528
529 // If this particular condition has not yet happened at this
530 // bytecode, then use the uncommon trap mechanism, and allow for
531 // a future recompilation if several traps occur here.
532 // If the throw is hot, try to use a more complicated inline mechanism
533 // which keeps execution inside the compiled code.
534 bool treat_throw_as_hot = false;
535 ciMethodData* md = method()->method_data();
536
537 if (ProfileTraps) {
538 if (too_many_traps(reason)) {
539 treat_throw_as_hot = true;
540 }
541 // (If there is no MDO at all, assume it is early in
542 // execution, and that any deopts are part of the
543 // startup transient, and don't need to be remembered.)
544
545 // Also, if there is a local exception handler, treat all throws
546 // as hot if there has been at least one in this method.
547 if (C->trap_count(reason) != 0
548 && method()->method_data()->trap_count(reason) != 0
549 && has_ex_handler()) {
550 treat_throw_as_hot = true;
551 }
552 }
553
554 // If this throw happens frequently, an uncommon trap might cause
555 // a performance pothole. If there is a local exception handler,
556 // and if this particular bytecode appears to be deoptimizing often,
557 // let us handle the throw inline, with a preconstructed instance.
558 // Note: If the deopt count has blown up, the uncommon trap
559 // runtime is going to flush this nmethod, not matter what.
560 if (treat_throw_as_hot
561 && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {
562 // If the throw is local, we use a pre-existing instance and
563 // punt on the backtrace. This would lead to a missing backtrace
564 // (a repeat of 4292742) if the backtrace object is ever asked
565 // for its backtrace.
566 // Fixing this remaining case of 4292742 requires some flavor of
567 // escape analysis. Leave that for the future.
568 ciInstance* ex_obj = NULL;
569 switch (reason) {
570 case Deoptimization::Reason_null_check:
571 ex_obj = env()->NullPointerException_instance();
572 break;
573 case Deoptimization::Reason_div0_check:
574 ex_obj = env()->ArithmeticException_instance();
575 break;
576 case Deoptimization::Reason_range_check:
577 ex_obj = env()->ArrayIndexOutOfBoundsException_instance();
578 break;
579 case Deoptimization::Reason_class_check:
580 if (java_bc() == Bytecodes::_aastore) {
581 ex_obj = env()->ArrayStoreException_instance();
582 } else {
583 ex_obj = env()->ClassCastException_instance();
584 }
585 break;
586 }
587 if (failing()) { stop(); return; } // exception allocation might fail
588 if (ex_obj != NULL) {
589 // Cheat with a preallocated exception object.
590 if (C->log() != NULL)
591 C->log()->elem("hot_throw preallocated='1' reason='%s'",
592 Deoptimization::trap_reason_name(reason));
593 const TypeInstPtr* ex_con = TypeInstPtr::make(ex_obj);
594 Node* ex_node = _gvn.transform(ConNode::make(ex_con));
595
596 // Clear the detail message of the preallocated exception object.
597 // Weblogic sometimes mutates the detail message of exceptions
598 // using reflection.
599 int offset = java_lang_Throwable::get_detailMessage_offset();
600 const TypePtr* adr_typ = ex_con->add_offset(offset);
601
602 Node *adr = basic_plus_adr(ex_node, ex_node, offset);
603 const TypeOopPtr* val_type = TypeOopPtr::make_from_klass(env()->String_klass());
604 // Conservatively release stores of object references.
605 Node *store = store_oop_to_object(control(), ex_node, adr, adr_typ, null(), val_type, T_OBJECT, MemNode::release);
606
607 add_exception_state(make_exception_state(ex_node));
608 return;
609 }
610 }
611
612 // %%% Maybe add entry to OptoRuntime which directly throws the exc.?
613 // It won't be much cheaper than bailing to the interp., since we'll
614 // have to pass up all the debug-info, and the runtime will have to
615 // create the stack trace.
616
617 // Usual case: Bail to interpreter.
618 // Reserve the right to recompile if we haven't seen anything yet.
619
620 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? C->method() : NULL;
621 Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;
622 if (treat_throw_as_hot
623 && (method()->method_data()->trap_recompiled_at(bci(), m)
624 || C->too_many_traps(reason))) {
625 // We cannot afford to take more traps here. Suffer in the interpreter.
626 if (C->log() != NULL)
627 C->log()->elem("hot_throw preallocated='0' reason='%s' mcount='%d'",
628 Deoptimization::trap_reason_name(reason),
629 C->trap_count(reason));
630 action = Deoptimization::Action_none;
631 }
632
633 // "must_throw" prunes the JVM state to include only the stack, if there
634 // are no local exception handlers. This should cut down on register
635 // allocation time and code size, by drastically reducing the number
636 // of in-edges on the call to the uncommon trap.
637
638 uncommon_trap(reason, action, (ciKlass*)NULL, (char*)NULL, must_throw);
639 }
640
641
642 //----------------------------PreserveJVMState---------------------------------
643 PreserveJVMState::PreserveJVMState(GraphKit* kit, bool clone_map) {
644 debug_only(kit->verify_map());
645 _kit = kit;
646 _map = kit->map(); // preserve the map
647 _sp = kit->sp();
648 kit->set_map(clone_map ? kit->clone_map() : NULL);
649 #ifdef ASSERT
650 _bci = kit->bci();
651 Parse* parser = kit->is_Parse();
652 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
653 _block = block;
654 #endif
655 }
656 PreserveJVMState::~PreserveJVMState() {
657 GraphKit* kit = _kit;
658 #ifdef ASSERT
659 assert(kit->bci() == _bci, "bci must not shift");
660 Parse* parser = kit->is_Parse();
661 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
662 assert(block == _block, "block must not shift");
663 #endif
664 kit->set_map(_map);
665 kit->set_sp(_sp);
666 }
667
668
669 //-----------------------------BuildCutout-------------------------------------
670 BuildCutout::BuildCutout(GraphKit* kit, Node* p, float prob, float cnt)
671 : PreserveJVMState(kit)
672 {
673 assert(p->is_Con() || p->is_Bool(), "test must be a bool");
674 SafePointNode* outer_map = _map; // preserved map is caller's
675 SafePointNode* inner_map = kit->map();
676 IfNode* iff = kit->create_and_map_if(outer_map->control(), p, prob, cnt);
677 outer_map->set_control(kit->gvn().transform( new IfTrueNode(iff) ));
678 inner_map->set_control(kit->gvn().transform( new IfFalseNode(iff) ));
679 }
680 BuildCutout::~BuildCutout() {
681 GraphKit* kit = _kit;
682 assert(kit->stopped(), "cutout code must stop, throw, return, etc.");
683 }
684
685 //---------------------------PreserveReexecuteState----------------------------
686 PreserveReexecuteState::PreserveReexecuteState(GraphKit* kit) {
687 assert(!kit->stopped(), "must call stopped() before");
688 _kit = kit;
689 _sp = kit->sp();
690 _reexecute = kit->jvms()->_reexecute;
691 }
692 PreserveReexecuteState::~PreserveReexecuteState() {
693 if (_kit->stopped()) return;
694 _kit->jvms()->_reexecute = _reexecute;
695 _kit->set_sp(_sp);
696 }
697
698 //------------------------------clone_map--------------------------------------
699 // Implementation of PreserveJVMState
700 //
701 // Only clone_map(...) here. If this function is only used in the
702 // PreserveJVMState class we may want to get rid of this extra
703 // function eventually and do it all there.
704
705 SafePointNode* GraphKit::clone_map() {
706 if (map() == NULL) return NULL;
707
708 // Clone the memory edge first
709 Node* mem = MergeMemNode::make(map()->memory());
710 gvn().set_type_bottom(mem);
711
712 SafePointNode *clonemap = (SafePointNode*)map()->clone();
713 JVMState* jvms = this->jvms();
714 JVMState* clonejvms = jvms->clone_shallow(C);
715 clonemap->set_memory(mem);
716 clonemap->set_jvms(clonejvms);
717 clonejvms->set_map(clonemap);
718 record_for_igvn(clonemap);
719 gvn().set_type_bottom(clonemap);
720 return clonemap;
721 }
722
723
724 //-----------------------------set_map_clone-----------------------------------
725 void GraphKit::set_map_clone(SafePointNode* m) {
726 _map = m;
727 _map = clone_map();
728 _map->set_next_exception(NULL);
729 debug_only(verify_map());
730 }
731
732
733 //----------------------------kill_dead_locals---------------------------------
734 // Detect any locals which are known to be dead, and force them to top.
735 void GraphKit::kill_dead_locals() {
736 // Consult the liveness information for the locals. If any
737 // of them are unused, then they can be replaced by top(). This
738 // should help register allocation time and cut down on the size
739 // of the deoptimization information.
740
741 // This call is made from many of the bytecode handling
742 // subroutines called from the Big Switch in do_one_bytecode.
743 // Every bytecode which might include a slow path is responsible
744 // for killing its dead locals. The more consistent we
745 // are about killing deads, the fewer useless phis will be
746 // constructed for them at various merge points.
747
748 // bci can be -1 (InvocationEntryBci). We return the entry
749 // liveness for the method.
750
751 if (method() == NULL || method()->code_size() == 0) {
752 // We are building a graph for a call to a native method.
753 // All locals are live.
754 return;
755 }
756
757 ResourceMark rm;
758
759 // Consult the liveness information for the locals. If any
760 // of them are unused, then they can be replaced by top(). This
761 // should help register allocation time and cut down on the size
762 // of the deoptimization information.
763 MethodLivenessResult live_locals = method()->liveness_at_bci(bci());
764
765 int len = (int)live_locals.size();
766 assert(len <= jvms()->loc_size(), "too many live locals");
767 for (int local = 0; local < len; local++) {
768 if (!live_locals.at(local)) {
769 set_local(local, top());
770 }
771 }
772 }
773
774 #ifdef ASSERT
775 //-------------------------dead_locals_are_killed------------------------------
776 // Return true if all dead locals are set to top in the map.
777 // Used to assert "clean" debug info at various points.
778 bool GraphKit::dead_locals_are_killed() {
779 if (method() == NULL || method()->code_size() == 0) {
780 // No locals need to be dead, so all is as it should be.
781 return true;
782 }
783
784 // Make sure somebody called kill_dead_locals upstream.
785 ResourceMark rm;
786 for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
787 if (jvms->loc_size() == 0) continue; // no locals to consult
788 SafePointNode* map = jvms->map();
789 ciMethod* method = jvms->method();
790 int bci = jvms->bci();
791 if (jvms == this->jvms()) {
792 bci = this->bci(); // it might not yet be synched
793 }
794 MethodLivenessResult live_locals = method->liveness_at_bci(bci);
795 int len = (int)live_locals.size();
796 if (!live_locals.is_valid() || len == 0)
797 // This method is trivial, or is poisoned by a breakpoint.
798 return true;
799 assert(len == jvms->loc_size(), "live map consistent with locals map");
800 for (int local = 0; local < len; local++) {
801 if (!live_locals.at(local) && map->local(jvms, local) != top()) {
802 if (PrintMiscellaneous && (Verbose || WizardMode)) {
803 tty->print_cr("Zombie local %d: ", local);
804 jvms->dump();
805 }
806 return false;
807 }
808 }
809 }
810 return true;
811 }
812
813 #endif //ASSERT
814
815 // Helper function for enforcing certain bytecodes to reexecute if
816 // deoptimization happens
817 static bool should_reexecute_implied_by_bytecode(JVMState *jvms, bool is_anewarray) {
818 ciMethod* cur_method = jvms->method();
819 int cur_bci = jvms->bci();
820 if (cur_method != NULL && cur_bci != InvocationEntryBci) {
821 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
822 return Interpreter::bytecode_should_reexecute(code) ||
823 is_anewarray && code == Bytecodes::_multianewarray;
824 // Reexecute _multianewarray bytecode which was replaced with
825 // sequence of [a]newarray. See Parse::do_multianewarray().
826 //
827 // Note: interpreter should not have it set since this optimization
828 // is limited by dimensions and guarded by flag so in some cases
829 // multianewarray() runtime calls will be generated and
830 // the bytecode should not be reexecutes (stack will not be reset).
831 } else
832 return false;
833 }
834
835 // Helper function for adding JVMState and debug information to node
836 void GraphKit::add_safepoint_edges(SafePointNode* call, bool must_throw) {
837 // Add the safepoint edges to the call (or other safepoint).
838
839 // Make sure dead locals are set to top. This
840 // should help register allocation time and cut down on the size
841 // of the deoptimization information.
842 assert(dead_locals_are_killed(), "garbage in debug info before safepoint");
843
844 // Walk the inline list to fill in the correct set of JVMState's
845 // Also fill in the associated edges for each JVMState.
846
847 // If the bytecode needs to be reexecuted we need to put
848 // the arguments back on the stack.
849 const bool should_reexecute = jvms()->should_reexecute();
850 JVMState* youngest_jvms = should_reexecute ? sync_jvms_for_reexecute() : sync_jvms();
851
852 // NOTE: set_bci (called from sync_jvms) might reset the reexecute bit to
853 // undefined if the bci is different. This is normal for Parse but it
854 // should not happen for LibraryCallKit because only one bci is processed.
855 assert(!is_LibraryCallKit() || (jvms()->should_reexecute() == should_reexecute),
856 "in LibraryCallKit the reexecute bit should not change");
857
858 // If we are guaranteed to throw, we can prune everything but the
859 // input to the current bytecode.
860 bool can_prune_locals = false;
861 uint stack_slots_not_pruned = 0;
862 int inputs = 0, depth = 0;
863 if (must_throw) {
864 assert(method() == youngest_jvms->method(), "sanity");
865 if (compute_stack_effects(inputs, depth)) {
866 can_prune_locals = true;
867 stack_slots_not_pruned = inputs;
868 }
869 }
870
871 if (env()->should_retain_local_variables()) {
872 // At any safepoint, this method can get breakpointed, which would
873 // then require an immediate deoptimization.
874 can_prune_locals = false; // do not prune locals
875 stack_slots_not_pruned = 0;
876 }
877
878 // do not scribble on the input jvms
879 JVMState* out_jvms = youngest_jvms->clone_deep(C);
880 call->set_jvms(out_jvms); // Start jvms list for call node
881
882 // For a known set of bytecodes, the interpreter should reexecute them if
883 // deoptimization happens. We set the reexecute state for them here
884 if (out_jvms->is_reexecute_undefined() && //don't change if already specified
885 should_reexecute_implied_by_bytecode(out_jvms, call->is_AllocateArray())) {
886 out_jvms->set_should_reexecute(true); //NOTE: youngest_jvms not changed
887 }
888
889 // Presize the call:
890 DEBUG_ONLY(uint non_debug_edges = call->req());
891 call->add_req_batch(top(), youngest_jvms->debug_depth());
892 assert(call->req() == non_debug_edges + youngest_jvms->debug_depth(), "");
893
894 // Set up edges so that the call looks like this:
895 // Call [state:] ctl io mem fptr retadr
896 // [parms:] parm0 ... parmN
897 // [root:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
898 // [...mid:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN [...]
899 // [young:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
900 // Note that caller debug info precedes callee debug info.
901
902 // Fill pointer walks backwards from "young:" to "root:" in the diagram above:
903 uint debug_ptr = call->req();
904
905 // Loop over the map input edges associated with jvms, add them
906 // to the call node, & reset all offsets to match call node array.
907 for (JVMState* in_jvms = youngest_jvms; in_jvms != NULL; ) {
908 uint debug_end = debug_ptr;
909 uint debug_start = debug_ptr - in_jvms->debug_size();
910 debug_ptr = debug_start; // back up the ptr
911
912 uint p = debug_start; // walks forward in [debug_start, debug_end)
913 uint j, k, l;
914 SafePointNode* in_map = in_jvms->map();
915 out_jvms->set_map(call);
916
917 if (can_prune_locals) {
918 assert(in_jvms->method() == out_jvms->method(), "sanity");
919 // If the current throw can reach an exception handler in this JVMS,
920 // then we must keep everything live that can reach that handler.
921 // As a quick and dirty approximation, we look for any handlers at all.
922 if (in_jvms->method()->has_exception_handlers()) {
923 can_prune_locals = false;
924 }
925 }
926
927 // Add the Locals
928 k = in_jvms->locoff();
929 l = in_jvms->loc_size();
930 out_jvms->set_locoff(p);
931 if (!can_prune_locals) {
932 for (j = 0; j < l; j++)
933 call->set_req(p++, in_map->in(k+j));
934 } else {
935 p += l; // already set to top above by add_req_batch
936 }
937
938 // Add the Expression Stack
939 k = in_jvms->stkoff();
940 l = in_jvms->sp();
941 out_jvms->set_stkoff(p);
942 if (!can_prune_locals) {
943 for (j = 0; j < l; j++)
944 call->set_req(p++, in_map->in(k+j));
945 } else if (can_prune_locals && stack_slots_not_pruned != 0) {
946 // Divide stack into {S0,...,S1}, where S0 is set to top.
947 uint s1 = stack_slots_not_pruned;
948 stack_slots_not_pruned = 0; // for next iteration
949 if (s1 > l) s1 = l;
950 uint s0 = l - s1;
951 p += s0; // skip the tops preinstalled by add_req_batch
952 for (j = s0; j < l; j++)
953 call->set_req(p++, in_map->in(k+j));
954 } else {
955 p += l; // already set to top above by add_req_batch
956 }
957
958 // Add the Monitors
959 k = in_jvms->monoff();
960 l = in_jvms->mon_size();
961 out_jvms->set_monoff(p);
962 for (j = 0; j < l; j++)
963 call->set_req(p++, in_map->in(k+j));
964
965 // Copy any scalar object fields.
966 k = in_jvms->scloff();
967 l = in_jvms->scl_size();
968 out_jvms->set_scloff(p);
969 for (j = 0; j < l; j++)
970 call->set_req(p++, in_map->in(k+j));
971
972 // Finish the new jvms.
973 out_jvms->set_endoff(p);
974
975 assert(out_jvms->endoff() == debug_end, "fill ptr must match");
976 assert(out_jvms->depth() == in_jvms->depth(), "depth must match");
977 assert(out_jvms->loc_size() == in_jvms->loc_size(), "size must match");
978 assert(out_jvms->mon_size() == in_jvms->mon_size(), "size must match");
979 assert(out_jvms->scl_size() == in_jvms->scl_size(), "size must match");
980 assert(out_jvms->debug_size() == in_jvms->debug_size(), "size must match");
981
982 // Update the two tail pointers in parallel.
983 out_jvms = out_jvms->caller();
984 in_jvms = in_jvms->caller();
985 }
986
987 assert(debug_ptr == non_debug_edges, "debug info must fit exactly");
988
989 // Test the correctness of JVMState::debug_xxx accessors:
990 assert(call->jvms()->debug_start() == non_debug_edges, "");
991 assert(call->jvms()->debug_end() == call->req(), "");
992 assert(call->jvms()->debug_depth() == call->req() - non_debug_edges, "");
993 }
994
995 bool GraphKit::compute_stack_effects(int& inputs, int& depth) {
996 Bytecodes::Code code = java_bc();
997 if (code == Bytecodes::_wide) {
998 code = method()->java_code_at_bci(bci() + 1);
999 }
1000
1001 BasicType rtype = T_ILLEGAL;
1002 int rsize = 0;
1003
1004 if (code != Bytecodes::_illegal) {
1005 depth = Bytecodes::depth(code); // checkcast=0, athrow=-1
1006 rtype = Bytecodes::result_type(code); // checkcast=P, athrow=V
1007 if (rtype < T_CONFLICT)
1008 rsize = type2size[rtype];
1009 }
1010
1011 switch (code) {
1012 case Bytecodes::_illegal:
1013 return false;
1014
1015 case Bytecodes::_ldc:
1016 case Bytecodes::_ldc_w:
1017 case Bytecodes::_ldc2_w:
1018 inputs = 0;
1019 break;
1020
1021 case Bytecodes::_dup: inputs = 1; break;
1022 case Bytecodes::_dup_x1: inputs = 2; break;
1023 case Bytecodes::_dup_x2: inputs = 3; break;
1024 case Bytecodes::_dup2: inputs = 2; break;
1025 case Bytecodes::_dup2_x1: inputs = 3; break;
1026 case Bytecodes::_dup2_x2: inputs = 4; break;
1027 case Bytecodes::_swap: inputs = 2; break;
1028 case Bytecodes::_arraylength: inputs = 1; break;
1029
1030 case Bytecodes::_getstatic:
1031 case Bytecodes::_putstatic:
1032 case Bytecodes::_getfield:
1033 case Bytecodes::_putfield:
1034 {
1035 bool ignored_will_link;
1036 ciField* field = method()->get_field_at_bci(bci(), ignored_will_link);
1037 int size = field->type()->size();
1038 bool is_get = (depth >= 0), is_static = (depth & 1);
1039 inputs = (is_static ? 0 : 1);
1040 if (is_get) {
1041 depth = size - inputs;
1042 } else {
1043 inputs += size; // putxxx pops the value from the stack
1044 depth = - inputs;
1045 }
1046 }
1047 break;
1048
1049 case Bytecodes::_invokevirtual:
1050 case Bytecodes::_invokespecial:
1051 case Bytecodes::_invokestatic:
1052 case Bytecodes::_invokedynamic:
1053 case Bytecodes::_invokeinterface:
1054 {
1055 bool ignored_will_link;
1056 ciSignature* declared_signature = NULL;
1057 ciMethod* ignored_callee = method()->get_method_at_bci(bci(), ignored_will_link, &declared_signature);
1058 assert(declared_signature != NULL, "cannot be null");
1059 inputs = declared_signature->arg_size_for_bc(code);
1060 int size = declared_signature->return_type()->size();
1061 depth = size - inputs;
1062 }
1063 break;
1064
1065 case Bytecodes::_multianewarray:
1066 {
1067 ciBytecodeStream iter(method());
1068 iter.reset_to_bci(bci());
1069 iter.next();
1070 inputs = iter.get_dimensions();
1071 assert(rsize == 1, "");
1072 depth = rsize - inputs;
1073 }
1074 break;
1075
1076 case Bytecodes::_ireturn:
1077 case Bytecodes::_lreturn:
1078 case Bytecodes::_freturn:
1079 case Bytecodes::_dreturn:
1080 case Bytecodes::_areturn:
1081 assert(rsize = -depth, "");
1082 inputs = rsize;
1083 break;
1084
1085 case Bytecodes::_jsr:
1086 case Bytecodes::_jsr_w:
1087 inputs = 0;
1088 depth = 1; // S.B. depth=1, not zero
1089 break;
1090
1091 default:
1092 // bytecode produces a typed result
1093 inputs = rsize - depth;
1094 assert(inputs >= 0, "");
1095 break;
1096 }
1097
1098 #ifdef ASSERT
1099 // spot check
1100 int outputs = depth + inputs;
1101 assert(outputs >= 0, "sanity");
1102 switch (code) {
1103 case Bytecodes::_checkcast: assert(inputs == 1 && outputs == 1, ""); break;
1104 case Bytecodes::_athrow: assert(inputs == 1 && outputs == 0, ""); break;
1105 case Bytecodes::_aload_0: assert(inputs == 0 && outputs == 1, ""); break;
1106 case Bytecodes::_return: assert(inputs == 0 && outputs == 0, ""); break;
1107 case Bytecodes::_drem: assert(inputs == 4 && outputs == 2, ""); break;
1108 }
1109 #endif //ASSERT
1110
1111 return true;
1112 }
1113
1114
1115
1116 //------------------------------basic_plus_adr---------------------------------
1117 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
1118 // short-circuit a common case
1119 if (offset == intcon(0)) return ptr;
1120 return _gvn.transform( new AddPNode(base, ptr, offset) );
1121 }
1122
1123 Node* GraphKit::ConvI2L(Node* offset) {
1124 // short-circuit a common case
1125 jint offset_con = find_int_con(offset, Type::OffsetBot);
1126 if (offset_con != Type::OffsetBot) {
1127 return longcon((jlong) offset_con);
1128 }
1129 return _gvn.transform( new ConvI2LNode(offset));
1130 }
1131
1132 Node* GraphKit::ConvI2UL(Node* offset) {
1133 juint offset_con = (juint) find_int_con(offset, Type::OffsetBot);
1134 if (offset_con != (juint) Type::OffsetBot) {
1135 return longcon((julong) offset_con);
1136 }
1137 Node* conv = _gvn.transform( new ConvI2LNode(offset));
1138 Node* mask = _gvn.transform(ConLNode::make((julong) max_juint));
1139 return _gvn.transform( new AndLNode(conv, mask) );
1140 }
1141
1142 Node* GraphKit::ConvL2I(Node* offset) {
1143 // short-circuit a common case
1144 jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);
1145 if (offset_con != (jlong)Type::OffsetBot) {
1146 return intcon((int) offset_con);
1147 }
1148 return _gvn.transform( new ConvL2INode(offset));
1149 }
1150
1151 //-------------------------load_object_klass-----------------------------------
1152 Node* GraphKit::load_object_klass(Node* obj) {
1153 // Special-case a fresh allocation to avoid building nodes:
1154 Node* akls = AllocateNode::Ideal_klass(obj, &_gvn);
1155 if (akls != NULL) return akls;
1156 Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());
1157 return _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), k_adr, TypeInstPtr::KLASS));
1158 }
1159
1160 //-------------------------load_array_length-----------------------------------
1161 Node* GraphKit::load_array_length(Node* array) {
1162 // Special-case a fresh allocation to avoid building nodes:
1163 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(array, &_gvn);
1164 Node *alen;
1165 if (alloc == NULL) {
1166 Node *r_adr = basic_plus_adr(array, arrayOopDesc::length_offset_in_bytes());
1167 alen = _gvn.transform( new LoadRangeNode(0, immutable_memory(), r_adr, TypeInt::POS));
1168 } else {
1169 alen = alloc->Ideal_length();
1170 Node* ccast = alloc->make_ideal_length(_gvn.type(array)->is_oopptr(), &_gvn);
1171 if (ccast != alen) {
1172 alen = _gvn.transform(ccast);
1173 }
1174 }
1175 return alen;
1176 }
1177
1178 //------------------------------do_null_check----------------------------------
1179 // Helper function to do a NULL pointer check. Returned value is
1180 // the incoming address with NULL casted away. You are allowed to use the
1181 // not-null value only if you are control dependent on the test.
1182 extern int explicit_null_checks_inserted,
1183 explicit_null_checks_elided;
1184 Node* GraphKit::null_check_common(Node* value, BasicType type,
1185 // optional arguments for variations:
1186 bool assert_null,
1187 Node* *null_control,
1188 bool speculative) {
1189 assert(!assert_null || null_control == NULL, "not both at once");
1190 if (stopped()) return top();
1191 if (!GenerateCompilerNullChecks && !assert_null && null_control == NULL) {
1192 // For some performance testing, we may wish to suppress null checking.
1193 value = cast_not_null(value); // Make it appear to be non-null (4962416).
1194 return value;
1195 }
1196 explicit_null_checks_inserted++;
1197
1198 // Construct NULL check
1199 Node *chk = NULL;
1200 switch(type) {
1201 case T_LONG : chk = new CmpLNode(value, _gvn.zerocon(T_LONG)); break;
1202 case T_INT : chk = new CmpINode(value, _gvn.intcon(0)); break;
1203 case T_ARRAY : // fall through
1204 type = T_OBJECT; // simplify further tests
1205 case T_OBJECT : {
1206 const Type *t = _gvn.type( value );
1207
1208 const TypeOopPtr* tp = t->isa_oopptr();
1209 if (tp != NULL && tp->klass() != NULL && !tp->klass()->is_loaded()
1210 // Only for do_null_check, not any of its siblings:
1211 && !assert_null && null_control == NULL) {
1212 // Usually, any field access or invocation on an unloaded oop type
1213 // will simply fail to link, since the statically linked class is
1214 // likely also to be unloaded. However, in -Xcomp mode, sometimes
1215 // the static class is loaded but the sharper oop type is not.
1216 // Rather than checking for this obscure case in lots of places,
1217 // we simply observe that a null check on an unloaded class
1218 // will always be followed by a nonsense operation, so we
1219 // can just issue the uncommon trap here.
1220 // Our access to the unloaded class will only be correct
1221 // after it has been loaded and initialized, which requires
1222 // a trip through the interpreter.
1223 #ifndef PRODUCT
1224 if (WizardMode) { tty->print("Null check of unloaded "); tp->klass()->print(); tty->cr(); }
1225 #endif
1226 uncommon_trap(Deoptimization::Reason_unloaded,
1227 Deoptimization::Action_reinterpret,
1228 tp->klass(), "!loaded");
1229 return top();
1230 }
1231
1232 if (assert_null) {
1233 // See if the type is contained in NULL_PTR.
1234 // If so, then the value is already null.
1235 if (t->higher_equal(TypePtr::NULL_PTR)) {
1236 explicit_null_checks_elided++;
1237 return value; // Elided null assert quickly!
1238 }
1239 } else {
1240 // See if mixing in the NULL pointer changes type.
1241 // If so, then the NULL pointer was not allowed in the original
1242 // type. In other words, "value" was not-null.
1243 if (t->meet(TypePtr::NULL_PTR) != t->remove_speculative()) {
1244 // same as: if (!TypePtr::NULL_PTR->higher_equal(t)) ...
1245 explicit_null_checks_elided++;
1246 return value; // Elided null check quickly!
1247 }
1248 }
1249 chk = new CmpPNode( value, null() );
1250 break;
1251 }
1252
1253 default:
1254 fatal("unexpected type: %s", type2name(type));
1255 }
1256 assert(chk != NULL, "sanity check");
1257 chk = _gvn.transform(chk);
1258
1259 BoolTest::mask btest = assert_null ? BoolTest::eq : BoolTest::ne;
1260 BoolNode *btst = new BoolNode( chk, btest);
1261 Node *tst = _gvn.transform( btst );
1262
1263 //-----------
1264 // if peephole optimizations occurred, a prior test existed.
1265 // If a prior test existed, maybe it dominates as we can avoid this test.
1266 if (tst != btst && type == T_OBJECT) {
1267 // At this point we want to scan up the CFG to see if we can
1268 // find an identical test (and so avoid this test altogether).
1269 Node *cfg = control();
1270 int depth = 0;
1271 while( depth < 16 ) { // Limit search depth for speed
1272 if( cfg->Opcode() == Op_IfTrue &&
1273 cfg->in(0)->in(1) == tst ) {
1274 // Found prior test. Use "cast_not_null" to construct an identical
1275 // CastPP (and hence hash to) as already exists for the prior test.
1276 // Return that casted value.
1277 if (assert_null) {
1278 replace_in_map(value, null());
1279 return null(); // do not issue the redundant test
1280 }
1281 Node *oldcontrol = control();
1282 set_control(cfg);
1283 Node *res = cast_not_null(value);
1284 set_control(oldcontrol);
1285 explicit_null_checks_elided++;
1286 return res;
1287 }
1288 cfg = IfNode::up_one_dom(cfg, /*linear_only=*/ true);
1289 if (cfg == NULL) break; // Quit at region nodes
1290 depth++;
1291 }
1292 }
1293
1294 //-----------
1295 // Branch to failure if null
1296 float ok_prob = PROB_MAX; // a priori estimate: nulls never happen
1297 Deoptimization::DeoptReason reason;
1298 if (assert_null) {
1299 reason = Deoptimization::Reason_null_assert;
1300 } else if (type == T_OBJECT) {
1301 reason = Deoptimization::reason_null_check(speculative);
1302 } else {
1303 reason = Deoptimization::Reason_div0_check;
1304 }
1305 // %%% Since Reason_unhandled is not recorded on a per-bytecode basis,
1306 // ciMethodData::has_trap_at will return a conservative -1 if any
1307 // must-be-null assertion has failed. This could cause performance
1308 // problems for a method after its first do_null_assert failure.
1309 // Consider using 'Reason_class_check' instead?
1310
1311 // To cause an implicit null check, we set the not-null probability
1312 // to the maximum (PROB_MAX). For an explicit check the probability
1313 // is set to a smaller value.
1314 if (null_control != NULL || too_many_traps(reason)) {
1315 // probability is less likely
1316 ok_prob = PROB_LIKELY_MAG(3);
1317 } else if (!assert_null &&
1318 (ImplicitNullCheckThreshold > 0) &&
1319 method() != NULL &&
1320 (method()->method_data()->trap_count(reason)
1321 >= (uint)ImplicitNullCheckThreshold)) {
1322 ok_prob = PROB_LIKELY_MAG(3);
1323 }
1324
1325 if (null_control != NULL) {
1326 IfNode* iff = create_and_map_if(control(), tst, ok_prob, COUNT_UNKNOWN);
1327 Node* null_true = _gvn.transform( new IfFalseNode(iff));
1328 set_control( _gvn.transform( new IfTrueNode(iff)));
1329 if (null_true == top())
1330 explicit_null_checks_elided++;
1331 (*null_control) = null_true;
1332 } else {
1333 BuildCutout unless(this, tst, ok_prob);
1334 // Check for optimizer eliding test at parse time
1335 if (stopped()) {
1336 // Failure not possible; do not bother making uncommon trap.
1337 explicit_null_checks_elided++;
1338 } else if (assert_null) {
1339 uncommon_trap(reason,
1340 Deoptimization::Action_make_not_entrant,
1341 NULL, "assert_null");
1342 } else {
1343 replace_in_map(value, zerocon(type));
1344 builtin_throw(reason);
1345 }
1346 }
1347
1348 // Must throw exception, fall-thru not possible?
1349 if (stopped()) {
1350 return top(); // No result
1351 }
1352
1353 if (assert_null) {
1354 // Cast obj to null on this path.
1355 replace_in_map(value, zerocon(type));
1356 return zerocon(type);
1357 }
1358
1359 // Cast obj to not-null on this path, if there is no null_control.
1360 // (If there is a null_control, a non-null value may come back to haunt us.)
1361 if (type == T_OBJECT) {
1362 Node* cast = cast_not_null(value, false);
1363 if (null_control == NULL || (*null_control) == top())
1364 replace_in_map(value, cast);
1365 value = cast;
1366 }
1367
1368 return value;
1369 }
1370
1371
1372 //------------------------------cast_not_null----------------------------------
1373 // Cast obj to not-null on this path
1374 Node* GraphKit::cast_not_null(Node* obj, bool do_replace_in_map) {
1375 const Type *t = _gvn.type(obj);
1376 const Type *t_not_null = t->join_speculative(TypePtr::NOTNULL);
1377 // Object is already not-null?
1378 if( t == t_not_null ) return obj;
1379
1380 Node *cast = new CastPPNode(obj,t_not_null);
1381 cast->init_req(0, control());
1382 cast = _gvn.transform( cast );
1383
1384 // Scan for instances of 'obj' in the current JVM mapping.
1385 // These instances are known to be not-null after the test.
1386 if (do_replace_in_map)
1387 replace_in_map(obj, cast);
1388
1389 return cast; // Return casted value
1390 }
1391
1392
1393 //--------------------------replace_in_map-------------------------------------
1394 void GraphKit::replace_in_map(Node* old, Node* neww) {
1395 if (old == neww) {
1396 return;
1397 }
1398
1399 map()->replace_edge(old, neww);
1400
1401 // Note: This operation potentially replaces any edge
1402 // on the map. This includes locals, stack, and monitors
1403 // of the current (innermost) JVM state.
1404
1405 // don't let inconsistent types from profiling escape this
1406 // method
1407
1408 const Type* told = _gvn.type(old);
1409 const Type* tnew = _gvn.type(neww);
1410
1411 if (!tnew->higher_equal(told)) {
1412 return;
1413 }
1414
1415 map()->record_replaced_node(old, neww);
1416 }
1417
1418
1419 //=============================================================================
1420 //--------------------------------memory---------------------------------------
1421 Node* GraphKit::memory(uint alias_idx) {
1422 MergeMemNode* mem = merged_memory();
1423 Node* p = mem->memory_at(alias_idx);
1424 _gvn.set_type(p, Type::MEMORY); // must be mapped
1425 return p;
1426 }
1427
1428 //-----------------------------reset_memory------------------------------------
1429 Node* GraphKit::reset_memory() {
1430 Node* mem = map()->memory();
1431 // do not use this node for any more parsing!
1432 debug_only( map()->set_memory((Node*)NULL) );
1433 return _gvn.transform( mem );
1434 }
1435
1436 //------------------------------set_all_memory---------------------------------
1437 void GraphKit::set_all_memory(Node* newmem) {
1438 Node* mergemem = MergeMemNode::make(newmem);
1439 gvn().set_type_bottom(mergemem);
1440 map()->set_memory(mergemem);
1441 }
1442
1443 //------------------------------set_all_memory_call----------------------------
1444 void GraphKit::set_all_memory_call(Node* call, bool separate_io_proj) {
1445 Node* newmem = _gvn.transform( new ProjNode(call, TypeFunc::Memory, separate_io_proj) );
1446 set_all_memory(newmem);
1447 }
1448
1449 //=============================================================================
1450 //
1451 // parser factory methods for MemNodes
1452 //
1453 // These are layered on top of the factory methods in LoadNode and StoreNode,
1454 // and integrate with the parser's memory state and _gvn engine.
1455 //
1456
1457 // factory methods in "int adr_idx"
1458 Node* GraphKit::make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
1459 int adr_idx,
1460 MemNode::MemOrd mo,
1461 LoadNode::ControlDependency control_dependency,
1462 bool require_atomic_access,
1463 bool unaligned,
1464 bool mismatched) {
1465 assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );
1466 const TypePtr* adr_type = NULL; // debug-mode-only argument
1467 debug_only(adr_type = C->get_adr_type(adr_idx));
1468 Node* mem = memory(adr_idx);
1469 Node* ld;
1470 if (require_atomic_access && bt == T_LONG) {
1471 ld = LoadLNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency);
1472 } else if (require_atomic_access && bt == T_DOUBLE) {
1473 ld = LoadDNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency);
1474 } else {
1475 ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt, mo, control_dependency);
1476 }
1477 if (unaligned) {
1478 ld->as_Load()->set_unaligned_access();
1479 }
1480 if (mismatched) {
1481 ld->as_Load()->set_mismatched_access();
1482 }
1483 ld = _gvn.transform(ld);
1484 if ((bt == T_OBJECT) && C->do_escape_analysis() || C->eliminate_boxing()) {
1485 // Improve graph before escape analysis and boxing elimination.
1486 record_for_igvn(ld);
1487 }
1488 return ld;
1489 }
1490
1491 Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,
1492 int adr_idx,
1493 MemNode::MemOrd mo,
1494 bool require_atomic_access,
1495 bool unaligned,
1496 bool mismatched) {
1497 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1498 const TypePtr* adr_type = NULL;
1499 debug_only(adr_type = C->get_adr_type(adr_idx));
1500 Node *mem = memory(adr_idx);
1501 Node* st;
1502 if (require_atomic_access && bt == T_LONG) {
1503 st = StoreLNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1504 } else if (require_atomic_access && bt == T_DOUBLE) {
1505 st = StoreDNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1506 } else {
1507 st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt, mo);
1508 }
1509 if (unaligned) {
1510 st->as_Store()->set_unaligned_access();
1511 }
1512 if (mismatched) {
1513 st->as_Store()->set_mismatched_access();
1514 }
1515 st = _gvn.transform(st);
1516 set_memory(st, adr_idx);
1517 // Back-to-back stores can only remove intermediate store with DU info
1518 // so push on worklist for optimizer.
1519 if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))
1520 record_for_igvn(st);
1521
1522 return st;
1523 }
1524
1525
1526 void GraphKit::pre_barrier(bool do_load,
1527 Node* ctl,
1528 Node* obj,
1529 Node* adr,
1530 uint adr_idx,
1531 Node* val,
1532 const TypeOopPtr* val_type,
1533 Node* pre_val,
1534 BasicType bt) {
1535
1536 BarrierSet* bs = Universe::heap()->barrier_set();
1537 set_control(ctl);
1538 switch (bs->kind()) {
1539 case BarrierSet::G1SATBCTLogging:
1540 g1_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
1541 break;
1542
1543 case BarrierSet::CardTableForRS:
1544 case BarrierSet::CardTableExtension:
1545 case BarrierSet::ModRef:
1546 break;
1547
1548 default :
1549 ShouldNotReachHere();
1550
1551 }
1552 }
1553
1554 bool GraphKit::can_move_pre_barrier() const {
1555 BarrierSet* bs = Universe::heap()->barrier_set();
1556 switch (bs->kind()) {
1557 case BarrierSet::G1SATBCTLogging:
1558 return true; // Can move it if no safepoint
1559
1560 case BarrierSet::CardTableForRS:
1561 case BarrierSet::CardTableExtension:
1562 case BarrierSet::ModRef:
1563 return true; // There is no pre-barrier
1564
1565 default :
1566 ShouldNotReachHere();
1567 }
1568 return false;
1569 }
1570
1571 void GraphKit::post_barrier(Node* ctl,
1572 Node* store,
1573 Node* obj,
1574 Node* adr,
1575 uint adr_idx,
1576 Node* val,
1577 BasicType bt,
1578 bool use_precise) {
1579 BarrierSet* bs = Universe::heap()->barrier_set();
1580 set_control(ctl);
1581 switch (bs->kind()) {
1582 case BarrierSet::G1SATBCTLogging:
1583 g1_write_barrier_post(store, obj, adr, adr_idx, val, bt, use_precise);
1584 break;
1585
1586 case BarrierSet::CardTableForRS:
1587 case BarrierSet::CardTableExtension:
1588 write_barrier_post(store, obj, adr, adr_idx, val, use_precise);
1589 break;
1590
1591 case BarrierSet::ModRef:
1592 break;
1593
1594 default :
1595 ShouldNotReachHere();
1596
1597 }
1598 }
1599
1600 Node* GraphKit::store_oop(Node* ctl,
1601 Node* obj,
1602 Node* adr,
1603 const TypePtr* adr_type,
1604 Node* val,
1605 const TypeOopPtr* val_type,
1606 BasicType bt,
1607 bool use_precise,
1608 MemNode::MemOrd mo,
1609 bool mismatched) {
1610 // Transformation of a value which could be NULL pointer (CastPP #NULL)
1611 // could be delayed during Parse (for example, in adjust_map_after_if()).
1612 // Execute transformation here to avoid barrier generation in such case.
1613 if (_gvn.type(val) == TypePtr::NULL_PTR)
1614 val = _gvn.makecon(TypePtr::NULL_PTR);
1615
1616 set_control(ctl);
1617 if (stopped()) return top(); // Dead path ?
1618
1619 assert(bt == T_OBJECT, "sanity");
1620 assert(val != NULL, "not dead path");
1621 uint adr_idx = C->get_alias_index(adr_type);
1622 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1623
1624 pre_barrier(true /* do_load */,
1625 control(), obj, adr, adr_idx, val, val_type,
1626 NULL /* pre_val */,
1627 bt);
1628
1629 Node* store = store_to_memory(control(), adr, val, bt, adr_idx, mo, mismatched);
1630 post_barrier(control(), store, obj, adr, adr_idx, val, bt, use_precise);
1631 return store;
1632 }
1633
1634 // Could be an array or object we don't know at compile time (unsafe ref.)
1635 Node* GraphKit::store_oop_to_unknown(Node* ctl,
1636 Node* obj, // containing obj
1637 Node* adr, // actual adress to store val at
1638 const TypePtr* adr_type,
1639 Node* val,
1640 BasicType bt,
1641 MemNode::MemOrd mo,
1642 bool mismatched) {
1643 Compile::AliasType* at = C->alias_type(adr_type);
1644 const TypeOopPtr* val_type = NULL;
1645 if (adr_type->isa_instptr()) {
1646 if (at->field() != NULL) {
1647 // known field. This code is a copy of the do_put_xxx logic.
1648 ciField* field = at->field();
1649 if (!field->type()->is_loaded()) {
1650 val_type = TypeInstPtr::BOTTOM;
1651 } else {
1652 val_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
1653 }
1654 }
1655 } else if (adr_type->isa_aryptr()) {
1656 val_type = adr_type->is_aryptr()->elem()->make_oopptr();
1657 }
1658 if (val_type == NULL) {
1659 val_type = TypeInstPtr::BOTTOM;
1660 }
1661 return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true, mo, mismatched);
1662 }
1663
1664
1665 //-------------------------array_element_address-------------------------
1666 Node* GraphKit::array_element_address(Node* ary, Node* idx, BasicType elembt,
1667 const TypeInt* sizetype) {
1668 uint shift = exact_log2(type2aelembytes(elembt));
1669 uint header = arrayOopDesc::base_offset_in_bytes(elembt);
1670
1671 // short-circuit a common case (saves lots of confusing waste motion)
1672 jint idx_con = find_int_con(idx, -1);
1673 if (idx_con >= 0) {
1674 intptr_t offset = header + ((intptr_t)idx_con << shift);
1675 return basic_plus_adr(ary, offset);
1676 }
1677
1678 // must be correct type for alignment purposes
1679 Node* base = basic_plus_adr(ary, header);
1680 idx = Compile::conv_I2X_index(&_gvn, idx, sizetype);
1681 Node* scale = _gvn.transform( new LShiftXNode(idx, intcon(shift)) );
1682 return basic_plus_adr(ary, base, scale);
1683 }
1684
1685 //-------------------------load_array_element-------------------------
1686 Node* GraphKit::load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype) {
1687 const Type* elemtype = arytype->elem();
1688 BasicType elembt = elemtype->array_element_basic_type();
1689 Node* adr = array_element_address(ary, idx, elembt, arytype->size());
1690 Node* ld = make_load(ctl, adr, elemtype, elembt, arytype, MemNode::unordered);
1691 return ld;
1692 }
1693
1694 //-------------------------set_arguments_for_java_call-------------------------
1695 // Arguments (pre-popped from the stack) are taken from the JVMS.
1696 void GraphKit::set_arguments_for_java_call(CallJavaNode* call) {
1697 // Add the call arguments:
1698 uint nargs = call->method()->arg_size();
1699 for (uint i = 0; i < nargs; i++) {
1700 Node* arg = argument(i);
1701 call->init_req(i + TypeFunc::Parms, arg);
1702 }
1703 }
1704
1705 //---------------------------set_edges_for_java_call---------------------------
1706 // Connect a newly created call into the current JVMS.
1707 // A return value node (if any) is returned from set_edges_for_java_call.
1708 void GraphKit::set_edges_for_java_call(CallJavaNode* call, bool must_throw, bool separate_io_proj) {
1709
1710 // Add the predefined inputs:
1711 call->init_req( TypeFunc::Control, control() );
1712 call->init_req( TypeFunc::I_O , i_o() );
1713 call->init_req( TypeFunc::Memory , reset_memory() );
1714 call->init_req( TypeFunc::FramePtr, frameptr() );
1715 call->init_req( TypeFunc::ReturnAdr, top() );
1716
1717 add_safepoint_edges(call, must_throw);
1718
1719 Node* xcall = _gvn.transform(call);
1720
1721 if (xcall == top()) {
1722 set_control(top());
1723 return;
1724 }
1725 assert(xcall == call, "call identity is stable");
1726
1727 // Re-use the current map to produce the result.
1728
1729 set_control(_gvn.transform(new ProjNode(call, TypeFunc::Control)));
1730 set_i_o( _gvn.transform(new ProjNode(call, TypeFunc::I_O , separate_io_proj)));
1731 set_all_memory_call(xcall, separate_io_proj);
1732
1733 //return xcall; // no need, caller already has it
1734 }
1735
1736 Node* GraphKit::set_results_for_java_call(CallJavaNode* call, bool separate_io_proj) {
1737 if (stopped()) return top(); // maybe the call folded up?
1738
1739 // Capture the return value, if any.
1740 Node* ret;
1741 if (call->method() == NULL ||
1742 call->method()->return_type()->basic_type() == T_VOID)
1743 ret = top();
1744 else ret = _gvn.transform(new ProjNode(call, TypeFunc::Parms));
1745
1746 // Note: Since any out-of-line call can produce an exception,
1747 // we always insert an I_O projection from the call into the result.
1748
1749 make_slow_call_ex(call, env()->Throwable_klass(), separate_io_proj);
1750
1751 if (separate_io_proj) {
1752 // The caller requested separate projections be used by the fall
1753 // through and exceptional paths, so replace the projections for
1754 // the fall through path.
1755 set_i_o(_gvn.transform( new ProjNode(call, TypeFunc::I_O) ));
1756 set_all_memory(_gvn.transform( new ProjNode(call, TypeFunc::Memory) ));
1757 }
1758 return ret;
1759 }
1760
1761 //--------------------set_predefined_input_for_runtime_call--------------------
1762 // Reading and setting the memory state is way conservative here.
1763 // The real problem is that I am not doing real Type analysis on memory,
1764 // so I cannot distinguish card mark stores from other stores. Across a GC
1765 // point the Store Barrier and the card mark memory has to agree. I cannot
1766 // have a card mark store and its barrier split across the GC point from
1767 // either above or below. Here I get that to happen by reading ALL of memory.
1768 // A better answer would be to separate out card marks from other memory.
1769 // For now, return the input memory state, so that it can be reused
1770 // after the call, if this call has restricted memory effects.
1771 Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call) {
1772 // Set fixed predefined input arguments
1773 Node* memory = reset_memory();
1774 call->init_req( TypeFunc::Control, control() );
1775 call->init_req( TypeFunc::I_O, top() ); // does no i/o
1776 call->init_req( TypeFunc::Memory, memory ); // may gc ptrs
1777 call->init_req( TypeFunc::FramePtr, frameptr() );
1778 call->init_req( TypeFunc::ReturnAdr, top() );
1779 return memory;
1780 }
1781
1782 //-------------------set_predefined_output_for_runtime_call--------------------
1783 // Set control and memory (not i_o) from the call.
1784 // If keep_mem is not NULL, use it for the output state,
1785 // except for the RawPtr output of the call, if hook_mem is TypeRawPtr::BOTTOM.
1786 // If hook_mem is NULL, this call produces no memory effects at all.
1787 // If hook_mem is a Java-visible memory slice (such as arraycopy operands),
1788 // then only that memory slice is taken from the call.
1789 // In the last case, we must put an appropriate memory barrier before
1790 // the call, so as to create the correct anti-dependencies on loads
1791 // preceding the call.
1792 void GraphKit::set_predefined_output_for_runtime_call(Node* call,
1793 Node* keep_mem,
1794 const TypePtr* hook_mem) {
1795 // no i/o
1796 set_control(_gvn.transform( new ProjNode(call,TypeFunc::Control) ));
1797 if (keep_mem) {
1798 // First clone the existing memory state
1799 set_all_memory(keep_mem);
1800 if (hook_mem != NULL) {
1801 // Make memory for the call
1802 Node* mem = _gvn.transform( new ProjNode(call, TypeFunc::Memory) );
1803 // Set the RawPtr memory state only. This covers all the heap top/GC stuff
1804 // We also use hook_mem to extract specific effects from arraycopy stubs.
1805 set_memory(mem, hook_mem);
1806 }
1807 // ...else the call has NO memory effects.
1808
1809 // Make sure the call advertises its memory effects precisely.
1810 // This lets us build accurate anti-dependences in gcm.cpp.
1811 assert(C->alias_type(call->adr_type()) == C->alias_type(hook_mem),
1812 "call node must be constructed correctly");
1813 } else {
1814 assert(hook_mem == NULL, "");
1815 // This is not a "slow path" call; all memory comes from the call.
1816 set_all_memory_call(call);
1817 }
1818 }
1819
1820
1821 // Replace the call with the current state of the kit.
1822 void GraphKit::replace_call(CallNode* call, Node* result, bool do_replaced_nodes) {
1823 JVMState* ejvms = NULL;
1824 if (has_exceptions()) {
1825 ejvms = transfer_exceptions_into_jvms();
1826 }
1827
1828 ReplacedNodes replaced_nodes = map()->replaced_nodes();
1829 ReplacedNodes replaced_nodes_exception;
1830 Node* ex_ctl = top();
1831
1832 SafePointNode* final_state = stop();
1833
1834 // Find all the needed outputs of this call
1835 CallProjections callprojs;
1836 call->extract_projections(&callprojs, true);
1837
1838 Node* init_mem = call->in(TypeFunc::Memory);
1839 Node* final_mem = final_state->in(TypeFunc::Memory);
1840 Node* final_ctl = final_state->in(TypeFunc::Control);
1841 Node* final_io = final_state->in(TypeFunc::I_O);
1842
1843 // Replace all the old call edges with the edges from the inlining result
1844 if (callprojs.fallthrough_catchproj != NULL) {
1845 C->gvn_replace_by(callprojs.fallthrough_catchproj, final_ctl);
1846 }
1847 if (callprojs.fallthrough_memproj != NULL) {
1848 if (final_mem->is_MergeMem()) {
1849 // Parser's exits MergeMem was not transformed but may be optimized
1850 final_mem = _gvn.transform(final_mem);
1851 }
1852 C->gvn_replace_by(callprojs.fallthrough_memproj, final_mem);
1853 }
1854 if (callprojs.fallthrough_ioproj != NULL) {
1855 C->gvn_replace_by(callprojs.fallthrough_ioproj, final_io);
1856 }
1857
1858 // Replace the result with the new result if it exists and is used
1859 if (callprojs.resproj != NULL && result != NULL) {
1860 C->gvn_replace_by(callprojs.resproj, result);
1861 }
1862
1863 if (ejvms == NULL) {
1864 // No exception edges to simply kill off those paths
1865 if (callprojs.catchall_catchproj != NULL) {
1866 C->gvn_replace_by(callprojs.catchall_catchproj, C->top());
1867 }
1868 if (callprojs.catchall_memproj != NULL) {
1869 C->gvn_replace_by(callprojs.catchall_memproj, C->top());
1870 }
1871 if (callprojs.catchall_ioproj != NULL) {
1872 C->gvn_replace_by(callprojs.catchall_ioproj, C->top());
1873 }
1874 // Replace the old exception object with top
1875 if (callprojs.exobj != NULL) {
1876 C->gvn_replace_by(callprojs.exobj, C->top());
1877 }
1878 } else {
1879 GraphKit ekit(ejvms);
1880
1881 // Load my combined exception state into the kit, with all phis transformed:
1882 SafePointNode* ex_map = ekit.combine_and_pop_all_exception_states();
1883 replaced_nodes_exception = ex_map->replaced_nodes();
1884
1885 Node* ex_oop = ekit.use_exception_state(ex_map);
1886
1887 if (callprojs.catchall_catchproj != NULL) {
1888 C->gvn_replace_by(callprojs.catchall_catchproj, ekit.control());
1889 ex_ctl = ekit.control();
1890 }
1891 if (callprojs.catchall_memproj != NULL) {
1892 C->gvn_replace_by(callprojs.catchall_memproj, ekit.reset_memory());
1893 }
1894 if (callprojs.catchall_ioproj != NULL) {
1895 C->gvn_replace_by(callprojs.catchall_ioproj, ekit.i_o());
1896 }
1897
1898 // Replace the old exception object with the newly created one
1899 if (callprojs.exobj != NULL) {
1900 C->gvn_replace_by(callprojs.exobj, ex_oop);
1901 }
1902 }
1903
1904 // Disconnect the call from the graph
1905 call->disconnect_inputs(NULL, C);
1906 C->gvn_replace_by(call, C->top());
1907
1908 // Clean up any MergeMems that feed other MergeMems since the
1909 // optimizer doesn't like that.
1910 if (final_mem->is_MergeMem()) {
1911 Node_List wl;
1912 for (SimpleDUIterator i(final_mem); i.has_next(); i.next()) {
1913 Node* m = i.get();
1914 if (m->is_MergeMem() && !wl.contains(m)) {
1915 wl.push(m);
1916 }
1917 }
1918 while (wl.size() > 0) {
1919 _gvn.transform(wl.pop());
1920 }
1921 }
1922
1923 if (callprojs.fallthrough_catchproj != NULL && !final_ctl->is_top() && do_replaced_nodes) {
1924 replaced_nodes.apply(C, final_ctl);
1925 }
1926 if (!ex_ctl->is_top() && do_replaced_nodes) {
1927 replaced_nodes_exception.apply(C, ex_ctl);
1928 }
1929 }
1930
1931
1932 //------------------------------increment_counter------------------------------
1933 // for statistics: increment a VM counter by 1
1934
1935 void GraphKit::increment_counter(address counter_addr) {
1936 Node* adr1 = makecon(TypeRawPtr::make(counter_addr));
1937 increment_counter(adr1);
1938 }
1939
1940 void GraphKit::increment_counter(Node* counter_addr) {
1941 int adr_type = Compile::AliasIdxRaw;
1942 Node* ctrl = control();
1943 Node* cnt = make_load(ctrl, counter_addr, TypeInt::INT, T_INT, adr_type, MemNode::unordered);
1944 Node* incr = _gvn.transform(new AddINode(cnt, _gvn.intcon(1)));
1945 store_to_memory(ctrl, counter_addr, incr, T_INT, adr_type, MemNode::unordered);
1946 }
1947
1948
1949 //------------------------------uncommon_trap----------------------------------
1950 // Bail out to the interpreter in mid-method. Implemented by calling the
1951 // uncommon_trap blob. This helper function inserts a runtime call with the
1952 // right debug info.
1953 void GraphKit::uncommon_trap(int trap_request,
1954 ciKlass* klass, const char* comment,
1955 bool must_throw,
1956 bool keep_exact_action) {
1957 if (failing()) stop();
1958 if (stopped()) return; // trap reachable?
1959
1960 // Note: If ProfileTraps is true, and if a deopt. actually
1961 // occurs here, the runtime will make sure an MDO exists. There is
1962 // no need to call method()->ensure_method_data() at this point.
1963
1964 // Set the stack pointer to the right value for reexecution:
1965 set_sp(reexecute_sp());
1966
1967 #ifdef ASSERT
1968 if (!must_throw) {
1969 // Make sure the stack has at least enough depth to execute
1970 // the current bytecode.
1971 int inputs, ignored_depth;
1972 if (compute_stack_effects(inputs, ignored_depth)) {
1973 assert(sp() >= inputs, "must have enough JVMS stack to execute %s: sp=%d, inputs=%d",
1974 Bytecodes::name(java_bc()), sp(), inputs);
1975 }
1976 }
1977 #endif
1978
1979 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
1980 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
1981
1982 switch (action) {
1983 case Deoptimization::Action_maybe_recompile:
1984 case Deoptimization::Action_reinterpret:
1985 // Temporary fix for 6529811 to allow virtual calls to be sure they
1986 // get the chance to go from mono->bi->mega
1987 if (!keep_exact_action &&
1988 Deoptimization::trap_request_index(trap_request) < 0 &&
1989 too_many_recompiles(reason)) {
1990 // This BCI is causing too many recompilations.
1991 if (C->log() != NULL) {
1992 C->log()->elem("observe that='trap_action_change' reason='%s' from='%s' to='none'",
1993 Deoptimization::trap_reason_name(reason),
1994 Deoptimization::trap_action_name(action));
1995 }
1996 action = Deoptimization::Action_none;
1997 trap_request = Deoptimization::make_trap_request(reason, action);
1998 } else {
1999 C->set_trap_can_recompile(true);
2000 }
2001 break;
2002 case Deoptimization::Action_make_not_entrant:
2003 C->set_trap_can_recompile(true);
2004 break;
2005 #ifdef ASSERT
2006 case Deoptimization::Action_none:
2007 case Deoptimization::Action_make_not_compilable:
2008 break;
2009 default:
2010 fatal("unknown action %d: %s", action, Deoptimization::trap_action_name(action));
2011 break;
2012 #endif
2013 }
2014
2015 if (TraceOptoParse) {
2016 char buf[100];
2017 tty->print_cr("Uncommon trap %s at bci:%d",
2018 Deoptimization::format_trap_request(buf, sizeof(buf),
2019 trap_request), bci());
2020 }
2021
2022 CompileLog* log = C->log();
2023 if (log != NULL) {
2024 int kid = (klass == NULL)? -1: log->identify(klass);
2025 log->begin_elem("uncommon_trap bci='%d'", bci());
2026 char buf[100];
2027 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
2028 trap_request));
2029 if (kid >= 0) log->print(" klass='%d'", kid);
2030 if (comment != NULL) log->print(" comment='%s'", comment);
2031 log->end_elem();
2032 }
2033
2034 // Make sure any guarding test views this path as very unlikely
2035 Node *i0 = control()->in(0);
2036 if (i0 != NULL && i0->is_If()) { // Found a guarding if test?
2037 IfNode *iff = i0->as_If();
2038 float f = iff->_prob; // Get prob
2039 if (control()->Opcode() == Op_IfTrue) {
2040 if (f > PROB_UNLIKELY_MAG(4))
2041 iff->_prob = PROB_MIN;
2042 } else {
2043 if (f < PROB_LIKELY_MAG(4))
2044 iff->_prob = PROB_MAX;
2045 }
2046 }
2047
2048 // Clear out dead values from the debug info.
2049 kill_dead_locals();
2050
2051 // Now insert the uncommon trap subroutine call
2052 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
2053 const TypePtr* no_memory_effects = NULL;
2054 // Pass the index of the class to be loaded
2055 Node* call = make_runtime_call(RC_NO_LEAF | RC_UNCOMMON |
2056 (must_throw ? RC_MUST_THROW : 0),
2057 OptoRuntime::uncommon_trap_Type(),
2058 call_addr, "uncommon_trap", no_memory_effects,
2059 intcon(trap_request));
2060 assert(call->as_CallStaticJava()->uncommon_trap_request() == trap_request,
2061 "must extract request correctly from the graph");
2062 assert(trap_request != 0, "zero value reserved by uncommon_trap_request");
2063
2064 call->set_req(TypeFunc::ReturnAdr, returnadr());
2065 // The debug info is the only real input to this call.
2066
2067 // Halt-and-catch fire here. The above call should never return!
2068 HaltNode* halt = new HaltNode(control(), frameptr());
2069 _gvn.set_type_bottom(halt);
2070 root()->add_req(halt);
2071
2072 stop_and_kill_map();
2073 }
2074
2075
2076 //--------------------------just_allocated_object------------------------------
2077 // Report the object that was just allocated.
2078 // It must be the case that there are no intervening safepoints.
2079 // We use this to determine if an object is so "fresh" that
2080 // it does not require card marks.
2081 Node* GraphKit::just_allocated_object(Node* current_control) {
2082 if (C->recent_alloc_ctl() == current_control)
2083 return C->recent_alloc_obj();
2084 return NULL;
2085 }
2086
2087
2088 void GraphKit::round_double_arguments(ciMethod* dest_method) {
2089 // (Note: TypeFunc::make has a cache that makes this fast.)
2090 const TypeFunc* tf = TypeFunc::make(dest_method);
2091 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2092 for (int j = 0; j < nargs; j++) {
2093 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2094 if( targ->basic_type() == T_DOUBLE ) {
2095 // If any parameters are doubles, they must be rounded before
2096 // the call, dstore_rounding does gvn.transform
2097 Node *arg = argument(j);
2098 arg = dstore_rounding(arg);
2099 set_argument(j, arg);
2100 }
2101 }
2102 }
2103
2104 /**
2105 * Record profiling data exact_kls for Node n with the type system so
2106 * that it can propagate it (speculation)
2107 *
2108 * @param n node that the type applies to
2109 * @param exact_kls type from profiling
2110 * @param maybe_null did profiling see null?
2111 *
2112 * @return node with improved type
2113 */
2114 Node* GraphKit::record_profile_for_speculation(Node* n, ciKlass* exact_kls, bool maybe_null) {
2115 const Type* current_type = _gvn.type(n);
2116 assert(UseTypeSpeculation, "type speculation must be on");
2117
2118 const TypePtr* speculative = current_type->speculative();
2119
2120 // Should the klass from the profile be recorded in the speculative type?
2121 if (current_type->would_improve_type(exact_kls, jvms()->depth())) {
2122 const TypeKlassPtr* tklass = TypeKlassPtr::make(exact_kls);
2123 const TypeOopPtr* xtype = tklass->as_instance_type();
2124 assert(xtype->klass_is_exact(), "Should be exact");
2125 // Any reason to believe n is not null (from this profiling or a previous one)?
2126 const TypePtr* ptr = (maybe_null && current_type->speculative_maybe_null()) ? TypePtr::BOTTOM : TypePtr::NOTNULL;
2127 // record the new speculative type's depth
2128 speculative = xtype->cast_to_ptr_type(ptr->ptr())->is_ptr();
2129 speculative = speculative->with_inline_depth(jvms()->depth());
2130 } else if (current_type->would_improve_ptr(maybe_null)) {
2131 // Profiling report that null was never seen so we can change the
2132 // speculative type to non null ptr.
2133 assert(!maybe_null, "nothing to improve");
2134 if (speculative == NULL) {
2135 speculative = TypePtr::NOTNULL;
2136 } else {
2137 const TypePtr* ptr = TypePtr::NOTNULL;
2138 speculative = speculative->cast_to_ptr_type(ptr->ptr())->is_ptr();
2139 }
2140 }
2141
2142 if (speculative != current_type->speculative()) {
2143 // Build a type with a speculative type (what we think we know
2144 // about the type but will need a guard when we use it)
2145 const TypeOopPtr* spec_type = TypeOopPtr::make(TypePtr::BotPTR, Type::OffsetBot, TypeOopPtr::InstanceBot, speculative);
2146 // We're changing the type, we need a new CheckCast node to carry
2147 // the new type. The new type depends on the control: what
2148 // profiling tells us is only valid from here as far as we can
2149 // tell.
2150 Node* cast = new CheckCastPPNode(control(), n, current_type->remove_speculative()->join_speculative(spec_type));
2151 cast = _gvn.transform(cast);
2152 replace_in_map(n, cast);
2153 n = cast;
2154 }
2155
2156 return n;
2157 }
2158
2159 /**
2160 * Record profiling data from receiver profiling at an invoke with the
2161 * type system so that it can propagate it (speculation)
2162 *
2163 * @param n receiver node
2164 *
2165 * @return node with improved type
2166 */
2167 Node* GraphKit::record_profiled_receiver_for_speculation(Node* n) {
2168 if (!UseTypeSpeculation) {
2169 return n;
2170 }
2171 ciKlass* exact_kls = profile_has_unique_klass();
2172 bool maybe_null = true;
2173 if (java_bc() == Bytecodes::_checkcast ||
2174 java_bc() == Bytecodes::_instanceof ||
2175 java_bc() == Bytecodes::_aastore) {
2176 ciProfileData* data = method()->method_data()->bci_to_data(bci());
2177 bool maybe_null = data == NULL ? true : data->as_BitData()->null_seen();
2178 }
2179 return record_profile_for_speculation(n, exact_kls, maybe_null);
2180 return n;
2181 }
2182
2183 /**
2184 * Record profiling data from argument profiling at an invoke with the
2185 * type system so that it can propagate it (speculation)
2186 *
2187 * @param dest_method target method for the call
2188 * @param bc what invoke bytecode is this?
2189 */
2190 void GraphKit::record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc) {
2191 if (!UseTypeSpeculation) {
2192 return;
2193 }
2194 const TypeFunc* tf = TypeFunc::make(dest_method);
2195 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2196 int skip = Bytecodes::has_receiver(bc) ? 1 : 0;
2197 for (int j = skip, i = 0; j < nargs && i < TypeProfileArgsLimit; j++) {
2198 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2199 if (targ->basic_type() == T_OBJECT || targ->basic_type() == T_ARRAY) {
2200 bool maybe_null = true;
2201 ciKlass* better_type = NULL;
2202 if (method()->argument_profiled_type(bci(), i, better_type, maybe_null)) {
2203 record_profile_for_speculation(argument(j), better_type, maybe_null);
2204 }
2205 i++;
2206 }
2207 }
2208 }
2209
2210 /**
2211 * Record profiling data from parameter profiling at an invoke with
2212 * the type system so that it can propagate it (speculation)
2213 */
2214 void GraphKit::record_profiled_parameters_for_speculation() {
2215 if (!UseTypeSpeculation) {
2216 return;
2217 }
2218 for (int i = 0, j = 0; i < method()->arg_size() ; i++) {
2219 if (_gvn.type(local(i))->isa_oopptr()) {
2220 bool maybe_null = true;
2221 ciKlass* better_type = NULL;
2222 if (method()->parameter_profiled_type(j, better_type, maybe_null)) {
2223 record_profile_for_speculation(local(i), better_type, maybe_null);
2224 }
2225 j++;
2226 }
2227 }
2228 }
2229
2230 /**
2231 * Record profiling data from return value profiling at an invoke with
2232 * the type system so that it can propagate it (speculation)
2233 */
2234 void GraphKit::record_profiled_return_for_speculation() {
2235 if (!UseTypeSpeculation) {
2236 return;
2237 }
2238 bool maybe_null = true;
2239 ciKlass* better_type = NULL;
2240 if (method()->return_profiled_type(bci(), better_type, maybe_null)) {
2241 // If profiling reports a single type for the return value,
2242 // feed it to the type system so it can propagate it as a
2243 // speculative type
2244 record_profile_for_speculation(stack(sp()-1), better_type, maybe_null);
2245 }
2246 }
2247
2248 void GraphKit::round_double_result(ciMethod* dest_method) {
2249 // A non-strict method may return a double value which has an extended
2250 // exponent, but this must not be visible in a caller which is 'strict'
2251 // If a strict caller invokes a non-strict callee, round a double result
2252
2253 BasicType result_type = dest_method->return_type()->basic_type();
2254 assert( method() != NULL, "must have caller context");
2255 if( result_type == T_DOUBLE && method()->is_strict() && !dest_method->is_strict() ) {
2256 // Destination method's return value is on top of stack
2257 // dstore_rounding() does gvn.transform
2258 Node *result = pop_pair();
2259 result = dstore_rounding(result);
2260 push_pair(result);
2261 }
2262 }
2263
2264 // rounding for strict float precision conformance
2265 Node* GraphKit::precision_rounding(Node* n) {
2266 return UseStrictFP && _method->flags().is_strict()
2267 && UseSSE == 0 && Matcher::strict_fp_requires_explicit_rounding
2268 ? _gvn.transform( new RoundFloatNode(0, n) )
2269 : n;
2270 }
2271
2272 // rounding for strict double precision conformance
2273 Node* GraphKit::dprecision_rounding(Node *n) {
2274 return UseStrictFP && _method->flags().is_strict()
2275 && UseSSE <= 1 && Matcher::strict_fp_requires_explicit_rounding
2276 ? _gvn.transform( new RoundDoubleNode(0, n) )
2277 : n;
2278 }
2279
2280 // rounding for non-strict double stores
2281 Node* GraphKit::dstore_rounding(Node* n) {
2282 return Matcher::strict_fp_requires_explicit_rounding
2283 && UseSSE <= 1
2284 ? _gvn.transform( new RoundDoubleNode(0, n) )
2285 : n;
2286 }
2287
2288 //=============================================================================
2289 // Generate a fast path/slow path idiom. Graph looks like:
2290 // [foo] indicates that 'foo' is a parameter
2291 //
2292 // [in] NULL
2293 // \ /
2294 // CmpP
2295 // Bool ne
2296 // If
2297 // / \
2298 // True False-<2>
2299 // / |
2300 // / cast_not_null
2301 // Load | | ^
2302 // [fast_test] | |
2303 // gvn to opt_test | |
2304 // / \ | <1>
2305 // True False |
2306 // | \\ |
2307 // [slow_call] \[fast_result]
2308 // Ctl Val \ \
2309 // | \ \
2310 // Catch <1> \ \
2311 // / \ ^ \ \
2312 // Ex No_Ex | \ \
2313 // | \ \ | \ <2> \
2314 // ... \ [slow_res] | | \ [null_result]
2315 // \ \--+--+--- | |
2316 // \ | / \ | /
2317 // --------Region Phi
2318 //
2319 //=============================================================================
2320 // Code is structured as a series of driver functions all called 'do_XXX' that
2321 // call a set of helper functions. Helper functions first, then drivers.
2322
2323 //------------------------------null_check_oop---------------------------------
2324 // Null check oop. Set null-path control into Region in slot 3.
2325 // Make a cast-not-nullness use the other not-null control. Return cast.
2326 Node* GraphKit::null_check_oop(Node* value, Node* *null_control,
2327 bool never_see_null,
2328 bool safe_for_replace,
2329 bool speculative) {
2330 // Initial NULL check taken path
2331 (*null_control) = top();
2332 Node* cast = null_check_common(value, T_OBJECT, false, null_control, speculative);
2333
2334 // Generate uncommon_trap:
2335 if (never_see_null && (*null_control) != top()) {
2336 // If we see an unexpected null at a check-cast we record it and force a
2337 // recompile; the offending check-cast will be compiled to handle NULLs.
2338 // If we see more than one offending BCI, then all checkcasts in the
2339 // method will be compiled to handle NULLs.
2340 PreserveJVMState pjvms(this);
2341 set_control(*null_control);
2342 replace_in_map(value, null());
2343 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculative);
2344 uncommon_trap(reason,
2345 Deoptimization::Action_make_not_entrant);
2346 (*null_control) = top(); // NULL path is dead
2347 }
2348 if ((*null_control) == top() && safe_for_replace) {
2349 replace_in_map(value, cast);
2350 }
2351
2352 // Cast away null-ness on the result
2353 return cast;
2354 }
2355
2356 //------------------------------opt_iff----------------------------------------
2357 // Optimize the fast-check IfNode. Set the fast-path region slot 2.
2358 // Return slow-path control.
2359 Node* GraphKit::opt_iff(Node* region, Node* iff) {
2360 IfNode *opt_iff = _gvn.transform(iff)->as_If();
2361
2362 // Fast path taken; set region slot 2
2363 Node *fast_taken = _gvn.transform( new IfFalseNode(opt_iff) );
2364 region->init_req(2,fast_taken); // Capture fast-control
2365
2366 // Fast path not-taken, i.e. slow path
2367 Node *slow_taken = _gvn.transform( new IfTrueNode(opt_iff) );
2368 return slow_taken;
2369 }
2370
2371 //-----------------------------make_runtime_call-------------------------------
2372 Node* GraphKit::make_runtime_call(int flags,
2373 const TypeFunc* call_type, address call_addr,
2374 const char* call_name,
2375 const TypePtr* adr_type,
2376 // The following parms are all optional.
2377 // The first NULL ends the list.
2378 Node* parm0, Node* parm1,
2379 Node* parm2, Node* parm3,
2380 Node* parm4, Node* parm5,
2381 Node* parm6, Node* parm7) {
2382 // Slow-path call
2383 bool is_leaf = !(flags & RC_NO_LEAF);
2384 bool has_io = (!is_leaf && !(flags & RC_NO_IO));
2385 if (call_name == NULL) {
2386 assert(!is_leaf, "must supply name for leaf");
2387 call_name = OptoRuntime::stub_name(call_addr);
2388 }
2389 CallNode* call;
2390 if (!is_leaf) {
2391 call = new CallStaticJavaNode(call_type, call_addr, call_name,
2392 bci(), adr_type);
2393 } else if (flags & RC_NO_FP) {
2394 call = new CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);
2395 } else {
2396 call = new CallLeafNode(call_type, call_addr, call_name, adr_type);
2397 }
2398
2399 // The following is similar to set_edges_for_java_call,
2400 // except that the memory effects of the call are restricted to AliasIdxRaw.
2401
2402 // Slow path call has no side-effects, uses few values
2403 bool wide_in = !(flags & RC_NARROW_MEM);
2404 bool wide_out = (C->get_alias_index(adr_type) == Compile::AliasIdxBot);
2405
2406 Node* prev_mem = NULL;
2407 if (wide_in) {
2408 prev_mem = set_predefined_input_for_runtime_call(call);
2409 } else {
2410 assert(!wide_out, "narrow in => narrow out");
2411 Node* narrow_mem = memory(adr_type);
2412 prev_mem = reset_memory();
2413 map()->set_memory(narrow_mem);
2414 set_predefined_input_for_runtime_call(call);
2415 }
2416
2417 // Hook each parm in order. Stop looking at the first NULL.
2418 if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);
2419 if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);
2420 if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);
2421 if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);
2422 if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);
2423 if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);
2424 if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);
2425 if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);
2426 /* close each nested if ===> */ } } } } } } } }
2427 assert(call->in(call->req()-1) != NULL, "must initialize all parms");
2428
2429 if (!is_leaf) {
2430 // Non-leaves can block and take safepoints:
2431 add_safepoint_edges(call, ((flags & RC_MUST_THROW) != 0));
2432 }
2433 // Non-leaves can throw exceptions:
2434 if (has_io) {
2435 call->set_req(TypeFunc::I_O, i_o());
2436 }
2437
2438 if (flags & RC_UNCOMMON) {
2439 // Set the count to a tiny probability. Cf. Estimate_Block_Frequency.
2440 // (An "if" probability corresponds roughly to an unconditional count.
2441 // Sort of.)
2442 call->set_cnt(PROB_UNLIKELY_MAG(4));
2443 }
2444
2445 Node* c = _gvn.transform(call);
2446 assert(c == call, "cannot disappear");
2447
2448 if (wide_out) {
2449 // Slow path call has full side-effects.
2450 set_predefined_output_for_runtime_call(call);
2451 } else {
2452 // Slow path call has few side-effects, and/or sets few values.
2453 set_predefined_output_for_runtime_call(call, prev_mem, adr_type);
2454 }
2455
2456 if (has_io) {
2457 set_i_o(_gvn.transform(new ProjNode(call, TypeFunc::I_O)));
2458 }
2459 return call;
2460
2461 }
2462
2463 //------------------------------merge_memory-----------------------------------
2464 // Merge memory from one path into the current memory state.
2465 void GraphKit::merge_memory(Node* new_mem, Node* region, int new_path) {
2466 for (MergeMemStream mms(merged_memory(), new_mem->as_MergeMem()); mms.next_non_empty2(); ) {
2467 Node* old_slice = mms.force_memory();
2468 Node* new_slice = mms.memory2();
2469 if (old_slice != new_slice) {
2470 PhiNode* phi;
2471 if (old_slice->is_Phi() && old_slice->as_Phi()->region() == region) {
2472 if (mms.is_empty()) {
2473 // clone base memory Phi's inputs for this memory slice
2474 assert(old_slice == mms.base_memory(), "sanity");
2475 phi = PhiNode::make(region, NULL, Type::MEMORY, mms.adr_type(C));
2476 _gvn.set_type(phi, Type::MEMORY);
2477 for (uint i = 1; i < phi->req(); i++) {
2478 phi->init_req(i, old_slice->in(i));
2479 }
2480 } else {
2481 phi = old_slice->as_Phi(); // Phi was generated already
2482 }
2483 } else {
2484 phi = PhiNode::make(region, old_slice, Type::MEMORY, mms.adr_type(C));
2485 _gvn.set_type(phi, Type::MEMORY);
2486 }
2487 phi->set_req(new_path, new_slice);
2488 mms.set_memory(phi);
2489 }
2490 }
2491 }
2492
2493 //------------------------------make_slow_call_ex------------------------------
2494 // Make the exception handler hookups for the slow call
2495 void GraphKit::make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj, bool deoptimize) {
2496 if (stopped()) return;
2497
2498 // Make a catch node with just two handlers: fall-through and catch-all
2499 Node* i_o = _gvn.transform( new ProjNode(call, TypeFunc::I_O, separate_io_proj) );
2500 Node* catc = _gvn.transform( new CatchNode(control(), i_o, 2) );
2501 Node* norm = _gvn.transform( new CatchProjNode(catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci) );
2502 Node* excp = _gvn.transform( new CatchProjNode(catc, CatchProjNode::catch_all_index, CatchProjNode::no_handler_bci) );
2503
2504 { PreserveJVMState pjvms(this);
2505 set_control(excp);
2506 set_i_o(i_o);
2507
2508 if (excp != top()) {
2509 if (deoptimize) {
2510 // Deoptimize if an exception is caught. Don't construct exception state in this case.
2511 uncommon_trap(Deoptimization::Reason_unhandled,
2512 Deoptimization::Action_none);
2513 } else {
2514 // Create an exception state also.
2515 // Use an exact type if the caller has specified a specific exception.
2516 const Type* ex_type = TypeOopPtr::make_from_klass_unique(ex_klass)->cast_to_ptr_type(TypePtr::NotNull);
2517 Node* ex_oop = new CreateExNode(ex_type, control(), i_o);
2518 add_exception_state(make_exception_state(_gvn.transform(ex_oop)));
2519 }
2520 }
2521 }
2522
2523 // Get the no-exception control from the CatchNode.
2524 set_control(norm);
2525 }
2526
2527 static IfNode* gen_subtype_check_compare(Node* ctrl, Node* in1, Node* in2, BoolTest::mask test, float p, PhaseGVN* gvn, BasicType bt) {
2528 Node* cmp = NULL;
2529 switch(bt) {
2530 case T_INT: cmp = new CmpINode(in1, in2); break;
2531 case T_ADDRESS: cmp = new CmpPNode(in1, in2); break;
2532 default: fatal("unexpected comparison type %s", type2name(bt));
2533 }
2534 gvn->transform(cmp);
2535 Node* bol = gvn->transform(new BoolNode(cmp, test));
2536 IfNode* iff = new IfNode(ctrl, bol, p, COUNT_UNKNOWN);
2537 gvn->transform(iff);
2538 if (!bol->is_Con()) gvn->record_for_igvn(iff);
2539 return iff;
2540 }
2541
2542
2543 //-------------------------------gen_subtype_check-----------------------------
2544 // Generate a subtyping check. Takes as input the subtype and supertype.
2545 // Returns 2 values: sets the default control() to the true path and returns
2546 // the false path. Only reads invariant memory; sets no (visible) memory.
2547 // The PartialSubtypeCheckNode sets the hidden 1-word cache in the encoding
2548 // but that's not exposed to the optimizer. This call also doesn't take in an
2549 // Object; if you wish to check an Object you need to load the Object's class
2550 // prior to coming here.
2551 Node* Phase::gen_subtype_check(Node* subklass, Node* superklass, Node** ctrl, MergeMemNode* mem, PhaseGVN* gvn) {
2552 Compile* C = gvn->C;
2553
2554 if ((*ctrl)->is_top()) {
2555 return C->top();
2556 }
2557
2558 // Fast check for identical types, perhaps identical constants.
2559 // The types can even be identical non-constants, in cases
2560 // involving Array.newInstance, Object.clone, etc.
2561 if (subklass == superklass)
2562 return C->top(); // false path is dead; no test needed.
2563
2564 if (gvn->type(superklass)->singleton()) {
2565 ciKlass* superk = gvn->type(superklass)->is_klassptr()->klass();
2566 ciKlass* subk = gvn->type(subklass)->is_klassptr()->klass();
2567
2568 // In the common case of an exact superklass, try to fold up the
2569 // test before generating code. You may ask, why not just generate
2570 // the code and then let it fold up? The answer is that the generated
2571 // code will necessarily include null checks, which do not always
2572 // completely fold away. If they are also needless, then they turn
2573 // into a performance loss. Example:
2574 // Foo[] fa = blah(); Foo x = fa[0]; fa[1] = x;
2575 // Here, the type of 'fa' is often exact, so the store check
2576 // of fa[1]=x will fold up, without testing the nullness of x.
2577 switch (C->static_subtype_check(superk, subk)) {
2578 case Compile::SSC_always_false:
2579 {
2580 Node* always_fail = *ctrl;
2581 *ctrl = gvn->C->top();
2582 return always_fail;
2583 }
2584 case Compile::SSC_always_true:
2585 return C->top();
2586 case Compile::SSC_easy_test:
2587 {
2588 // Just do a direct pointer compare and be done.
2589 IfNode* iff = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_STATIC_FREQUENT, gvn, T_ADDRESS);
2590 *ctrl = gvn->transform(new IfTrueNode(iff));
2591 return gvn->transform(new IfFalseNode(iff));
2592 }
2593 case Compile::SSC_full_test:
2594 break;
2595 default:
2596 ShouldNotReachHere();
2597 }
2598 }
2599
2600 // %%% Possible further optimization: Even if the superklass is not exact,
2601 // if the subklass is the unique subtype of the superklass, the check
2602 // will always succeed. We could leave a dependency behind to ensure this.
2603
2604 // First load the super-klass's check-offset
2605 Node *p1 = gvn->transform(new AddPNode(superklass, superklass, gvn->MakeConX(in_bytes(Klass::super_check_offset_offset()))));
2606 Node* m = mem->memory_at(C->get_alias_index(gvn->type(p1)->is_ptr()));
2607 Node *chk_off = gvn->transform(new LoadINode(NULL, m, p1, gvn->type(p1)->is_ptr(), TypeInt::INT, MemNode::unordered));
2608 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset());
2609 bool might_be_cache = (gvn->find_int_con(chk_off, cacheoff_con) == cacheoff_con);
2610
2611 // Load from the sub-klass's super-class display list, or a 1-word cache of
2612 // the secondary superclass list, or a failing value with a sentinel offset
2613 // if the super-klass is an interface or exceptionally deep in the Java
2614 // hierarchy and we have to scan the secondary superclass list the hard way.
2615 // Worst-case type is a little odd: NULL is allowed as a result (usually
2616 // klass loads can never produce a NULL).
2617 Node *chk_off_X = chk_off;
2618 #ifdef _LP64
2619 chk_off_X = gvn->transform(new ConvI2LNode(chk_off_X));
2620 #endif
2621 Node *p2 = gvn->transform(new AddPNode(subklass,subklass,chk_off_X));
2622 // For some types like interfaces the following loadKlass is from a 1-word
2623 // cache which is mutable so can't use immutable memory. Other
2624 // types load from the super-class display table which is immutable.
2625 m = mem->memory_at(C->get_alias_index(gvn->type(p2)->is_ptr()));
2626 Node *kmem = might_be_cache ? m : C->immutable_memory();
2627 Node *nkls = gvn->transform(LoadKlassNode::make(*gvn, NULL, kmem, p2, gvn->type(p2)->is_ptr(), TypeKlassPtr::OBJECT_OR_NULL));
2628
2629 // Compile speed common case: ARE a subtype and we canNOT fail
2630 if( superklass == nkls )
2631 return C->top(); // false path is dead; no test needed.
2632
2633 // See if we get an immediate positive hit. Happens roughly 83% of the
2634 // time. Test to see if the value loaded just previously from the subklass
2635 // is exactly the superklass.
2636 IfNode *iff1 = gen_subtype_check_compare(*ctrl, superklass, nkls, BoolTest::eq, PROB_LIKELY(0.83f), gvn, T_ADDRESS);
2637 Node *iftrue1 = gvn->transform( new IfTrueNode (iff1));
2638 *ctrl = gvn->transform(new IfFalseNode(iff1));
2639
2640 // Compile speed common case: Check for being deterministic right now. If
2641 // chk_off is a constant and not equal to cacheoff then we are NOT a
2642 // subklass. In this case we need exactly the 1 test above and we can
2643 // return those results immediately.
2644 if (!might_be_cache) {
2645 Node* not_subtype_ctrl = *ctrl;
2646 *ctrl = iftrue1; // We need exactly the 1 test above
2647 return not_subtype_ctrl;
2648 }
2649
2650 // Gather the various success & failures here
2651 RegionNode *r_ok_subtype = new RegionNode(4);
2652 gvn->record_for_igvn(r_ok_subtype);
2653 RegionNode *r_not_subtype = new RegionNode(3);
2654 gvn->record_for_igvn(r_not_subtype);
2655
2656 r_ok_subtype->init_req(1, iftrue1);
2657
2658 // Check for immediate negative hit. Happens roughly 11% of the time (which
2659 // is roughly 63% of the remaining cases). Test to see if the loaded
2660 // check-offset points into the subklass display list or the 1-element
2661 // cache. If it points to the display (and NOT the cache) and the display
2662 // missed then it's not a subtype.
2663 Node *cacheoff = gvn->intcon(cacheoff_con);
2664 IfNode *iff2 = gen_subtype_check_compare(*ctrl, chk_off, cacheoff, BoolTest::ne, PROB_LIKELY(0.63f), gvn, T_INT);
2665 r_not_subtype->init_req(1, gvn->transform(new IfTrueNode (iff2)));
2666 *ctrl = gvn->transform(new IfFalseNode(iff2));
2667
2668 // Check for self. Very rare to get here, but it is taken 1/3 the time.
2669 // No performance impact (too rare) but allows sharing of secondary arrays
2670 // which has some footprint reduction.
2671 IfNode *iff3 = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_LIKELY(0.36f), gvn, T_ADDRESS);
2672 r_ok_subtype->init_req(2, gvn->transform(new IfTrueNode(iff3)));
2673 *ctrl = gvn->transform(new IfFalseNode(iff3));
2674
2675 // -- Roads not taken here: --
2676 // We could also have chosen to perform the self-check at the beginning
2677 // of this code sequence, as the assembler does. This would not pay off
2678 // the same way, since the optimizer, unlike the assembler, can perform
2679 // static type analysis to fold away many successful self-checks.
2680 // Non-foldable self checks work better here in second position, because
2681 // the initial primary superclass check subsumes a self-check for most
2682 // types. An exception would be a secondary type like array-of-interface,
2683 // which does not appear in its own primary supertype display.
2684 // Finally, we could have chosen to move the self-check into the
2685 // PartialSubtypeCheckNode, and from there out-of-line in a platform
2686 // dependent manner. But it is worthwhile to have the check here,
2687 // where it can be perhaps be optimized. The cost in code space is
2688 // small (register compare, branch).
2689
2690 // Now do a linear scan of the secondary super-klass array. Again, no real
2691 // performance impact (too rare) but it's gotta be done.
2692 // Since the code is rarely used, there is no penalty for moving it
2693 // out of line, and it can only improve I-cache density.
2694 // The decision to inline or out-of-line this final check is platform
2695 // dependent, and is found in the AD file definition of PartialSubtypeCheck.
2696 Node* psc = gvn->transform(
2697 new PartialSubtypeCheckNode(*ctrl, subklass, superklass));
2698
2699 IfNode *iff4 = gen_subtype_check_compare(*ctrl, psc, gvn->zerocon(T_OBJECT), BoolTest::ne, PROB_FAIR, gvn, T_ADDRESS);
2700 r_not_subtype->init_req(2, gvn->transform(new IfTrueNode (iff4)));
2701 r_ok_subtype ->init_req(3, gvn->transform(new IfFalseNode(iff4)));
2702
2703 // Return false path; set default control to true path.
2704 *ctrl = gvn->transform(r_ok_subtype);
2705 return gvn->transform(r_not_subtype);
2706 }
2707
2708 // Profile-driven exact type check:
2709 Node* GraphKit::type_check_receiver(Node* receiver, ciKlass* klass,
2710 float prob,
2711 Node* *casted_receiver) {
2712 const TypeKlassPtr* tklass = TypeKlassPtr::make(klass);
2713 Node* recv_klass = load_object_klass(receiver);
2714 Node* want_klass = makecon(tklass);
2715 Node* cmp = _gvn.transform( new CmpPNode(recv_klass, want_klass) );
2716 Node* bol = _gvn.transform( new BoolNode(cmp, BoolTest::eq) );
2717 IfNode* iff = create_and_xform_if(control(), bol, prob, COUNT_UNKNOWN);
2718 set_control( _gvn.transform( new IfTrueNode (iff) ));
2719 Node* fail = _gvn.transform( new IfFalseNode(iff) );
2720
2721 const TypeOopPtr* recv_xtype = tklass->as_instance_type();
2722 assert(recv_xtype->klass_is_exact(), "");
2723
2724 // Subsume downstream occurrences of receiver with a cast to
2725 // recv_xtype, since now we know what the type will be.
2726 Node* cast = new CheckCastPPNode(control(), receiver, recv_xtype);
2727 (*casted_receiver) = _gvn.transform(cast);
2728 // (User must make the replace_in_map call.)
2729
2730 return fail;
2731 }
2732
2733
2734 //------------------------------seems_never_null-------------------------------
2735 // Use null_seen information if it is available from the profile.
2736 // If we see an unexpected null at a type check we record it and force a
2737 // recompile; the offending check will be recompiled to handle NULLs.
2738 // If we see several offending BCIs, then all checks in the
2739 // method will be recompiled.
2740 bool GraphKit::seems_never_null(Node* obj, ciProfileData* data, bool& speculating) {
2741 speculating = !_gvn.type(obj)->speculative_maybe_null();
2742 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculating);
2743 if (UncommonNullCast // Cutout for this technique
2744 && obj != null() // And not the -Xcomp stupid case?
2745 && !too_many_traps(reason)
2746 ) {
2747 if (speculating) {
2748 return true;
2749 }
2750 if (data == NULL)
2751 // Edge case: no mature data. Be optimistic here.
2752 return true;
2753 // If the profile has not seen a null, assume it won't happen.
2754 assert(java_bc() == Bytecodes::_checkcast ||
2755 java_bc() == Bytecodes::_instanceof ||
2756 java_bc() == Bytecodes::_aastore, "MDO must collect null_seen bit here");
2757 return !data->as_BitData()->null_seen();
2758 }
2759 speculating = false;
2760 return false;
2761 }
2762
2763 //------------------------maybe_cast_profiled_receiver-------------------------
2764 // If the profile has seen exactly one type, narrow to exactly that type.
2765 // Subsequent type checks will always fold up.
2766 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
2767 ciKlass* require_klass,
2768 ciKlass* spec_klass,
2769 bool safe_for_replace) {
2770 if (!UseTypeProfile || !TypeProfileCasts) return NULL;
2771
2772 Deoptimization::DeoptReason reason = Deoptimization::reason_class_check(spec_klass != NULL);
2773
2774 // Make sure we haven't already deoptimized from this tactic.
2775 if (too_many_traps(reason) || too_many_recompiles(reason))
2776 return NULL;
2777
2778 // (No, this isn't a call, but it's enough like a virtual call
2779 // to use the same ciMethod accessor to get the profile info...)
2780 // If we have a speculative type use it instead of profiling (which
2781 // may not help us)
2782 ciKlass* exact_kls = spec_klass == NULL ? profile_has_unique_klass() : spec_klass;
2783 if (exact_kls != NULL) {// no cast failures here
2784 if (require_klass == NULL ||
2785 C->static_subtype_check(require_klass, exact_kls) == Compile::SSC_always_true) {
2786 // If we narrow the type to match what the type profile sees or
2787 // the speculative type, we can then remove the rest of the
2788 // cast.
2789 // This is a win, even if the exact_kls is very specific,
2790 // because downstream operations, such as method calls,
2791 // will often benefit from the sharper type.
2792 Node* exact_obj = not_null_obj; // will get updated in place...
2793 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2794 &exact_obj);
2795 { PreserveJVMState pjvms(this);
2796 set_control(slow_ctl);
2797 uncommon_trap_exact(reason, Deoptimization::Action_maybe_recompile);
2798 }
2799 if (safe_for_replace) {
2800 replace_in_map(not_null_obj, exact_obj);
2801 }
2802 return exact_obj;
2803 }
2804 // assert(ssc == Compile::SSC_always_true)... except maybe the profile lied to us.
2805 }
2806
2807 return NULL;
2808 }
2809
2810 /**
2811 * Cast obj to type and emit guard unless we had too many traps here
2812 * already
2813 *
2814 * @param obj node being casted
2815 * @param type type to cast the node to
2816 * @param not_null true if we know node cannot be null
2817 */
2818 Node* GraphKit::maybe_cast_profiled_obj(Node* obj,
2819 ciKlass* type,
2820 bool not_null) {
2821 if (stopped()) {
2822 return obj;
2823 }
2824
2825 // type == NULL if profiling tells us this object is always null
2826 if (type != NULL) {
2827 Deoptimization::DeoptReason class_reason = Deoptimization::Reason_speculate_class_check;
2828 Deoptimization::DeoptReason null_reason = Deoptimization::Reason_speculate_null_check;
2829
2830 if (!too_many_traps(null_reason) && !too_many_recompiles(null_reason) &&
2831 !too_many_traps(class_reason) &&
2832 !too_many_recompiles(class_reason)) {
2833 Node* not_null_obj = NULL;
2834 // not_null is true if we know the object is not null and
2835 // there's no need for a null check
2836 if (!not_null) {
2837 Node* null_ctl = top();
2838 not_null_obj = null_check_oop(obj, &null_ctl, true, true, true);
2839 assert(null_ctl->is_top(), "no null control here");
2840 } else {
2841 not_null_obj = obj;
2842 }
2843
2844 Node* exact_obj = not_null_obj;
2845 ciKlass* exact_kls = type;
2846 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2847 &exact_obj);
2848 {
2849 PreserveJVMState pjvms(this);
2850 set_control(slow_ctl);
2851 uncommon_trap_exact(class_reason, Deoptimization::Action_maybe_recompile);
2852 }
2853 replace_in_map(not_null_obj, exact_obj);
2854 obj = exact_obj;
2855 }
2856 } else {
2857 if (!too_many_traps(Deoptimization::Reason_null_assert) &&
2858 !too_many_recompiles(Deoptimization::Reason_null_assert)) {
2859 Node* exact_obj = null_assert(obj);
2860 replace_in_map(obj, exact_obj);
2861 obj = exact_obj;
2862 }
2863 }
2864 return obj;
2865 }
2866
2867 //-------------------------------gen_instanceof--------------------------------
2868 // Generate an instance-of idiom. Used by both the instance-of bytecode
2869 // and the reflective instance-of call.
2870 Node* GraphKit::gen_instanceof(Node* obj, Node* superklass, bool safe_for_replace) {
2871 kill_dead_locals(); // Benefit all the uncommon traps
2872 assert( !stopped(), "dead parse path should be checked in callers" );
2873 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()),
2874 "must check for not-null not-dead klass in callers");
2875
2876 // Make the merge point
2877 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT };
2878 RegionNode* region = new RegionNode(PATH_LIMIT);
2879 Node* phi = new PhiNode(region, TypeInt::BOOL);
2880 C->set_has_split_ifs(true); // Has chance for split-if optimization
2881
2882 ciProfileData* data = NULL;
2883 if (java_bc() == Bytecodes::_instanceof) { // Only for the bytecode
2884 data = method()->method_data()->bci_to_data(bci());
2885 }
2886 bool speculative_not_null = false;
2887 bool never_see_null = (ProfileDynamicTypes // aggressive use of profile
2888 && seems_never_null(obj, data, speculative_not_null));
2889
2890 // Null check; get casted pointer; set region slot 3
2891 Node* null_ctl = top();
2892 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
2893
2894 // If not_null_obj is dead, only null-path is taken
2895 if (stopped()) { // Doing instance-of on a NULL?
2896 set_control(null_ctl);
2897 return intcon(0);
2898 }
2899 region->init_req(_null_path, null_ctl);
2900 phi ->init_req(_null_path, intcon(0)); // Set null path value
2901 if (null_ctl == top()) {
2902 // Do this eagerly, so that pattern matches like is_diamond_phi
2903 // will work even during parsing.
2904 assert(_null_path == PATH_LIMIT-1, "delete last");
2905 region->del_req(_null_path);
2906 phi ->del_req(_null_path);
2907 }
2908
2909 // Do we know the type check always succeed?
2910 bool known_statically = false;
2911 if (_gvn.type(superklass)->singleton()) {
2912 ciKlass* superk = _gvn.type(superklass)->is_klassptr()->klass();
2913 ciKlass* subk = _gvn.type(obj)->is_oopptr()->klass();
2914 if (subk != NULL && subk->is_loaded()) {
2915 int static_res = C->static_subtype_check(superk, subk);
2916 known_statically = (static_res == Compile::SSC_always_true || static_res == Compile::SSC_always_false);
2917 }
2918 }
2919
2920 if (known_statically && UseTypeSpeculation) {
2921 // If we know the type check always succeeds then we don't use the
2922 // profiling data at this bytecode. Don't lose it, feed it to the
2923 // type system as a speculative type.
2924 not_null_obj = record_profiled_receiver_for_speculation(not_null_obj);
2925 } else {
2926 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
2927 // We may not have profiling here or it may not help us. If we
2928 // have a speculative type use it to perform an exact cast.
2929 ciKlass* spec_obj_type = obj_type->speculative_type();
2930 if (spec_obj_type != NULL || (ProfileDynamicTypes && data != NULL)) {
2931 Node* cast_obj = maybe_cast_profiled_receiver(not_null_obj, NULL, spec_obj_type, safe_for_replace);
2932 if (stopped()) { // Profile disagrees with this path.
2933 set_control(null_ctl); // Null is the only remaining possibility.
2934 return intcon(0);
2935 }
2936 if (cast_obj != NULL) {
2937 not_null_obj = cast_obj;
2938 }
2939 }
2940 }
2941
2942 // Load the object's klass
2943 Node* obj_klass = load_object_klass(not_null_obj);
2944
2945 // Generate the subtype check
2946 Node* not_subtype_ctrl = gen_subtype_check(obj_klass, superklass);
2947
2948 // Plug in the success path to the general merge in slot 1.
2949 region->init_req(_obj_path, control());
2950 phi ->init_req(_obj_path, intcon(1));
2951
2952 // Plug in the failing path to the general merge in slot 2.
2953 region->init_req(_fail_path, not_subtype_ctrl);
2954 phi ->init_req(_fail_path, intcon(0));
2955
2956 // Return final merged results
2957 set_control( _gvn.transform(region) );
2958 record_for_igvn(region);
2959 return _gvn.transform(phi);
2960 }
2961
2962 //-------------------------------gen_checkcast---------------------------------
2963 // Generate a checkcast idiom. Used by both the checkcast bytecode and the
2964 // array store bytecode. Stack must be as-if BEFORE doing the bytecode so the
2965 // uncommon-trap paths work. Adjust stack after this call.
2966 // If failure_control is supplied and not null, it is filled in with
2967 // the control edge for the cast failure. Otherwise, an appropriate
2968 // uncommon trap or exception is thrown.
2969 Node* GraphKit::gen_checkcast(Node *obj, Node* superklass,
2970 Node* *failure_control) {
2971 kill_dead_locals(); // Benefit all the uncommon traps
2972 const TypeKlassPtr *tk = _gvn.type(superklass)->is_klassptr();
2973 const Type *toop = TypeOopPtr::make_from_klass(tk->klass());
2974
2975 // Fast cutout: Check the case that the cast is vacuously true.
2976 // This detects the common cases where the test will short-circuit
2977 // away completely. We do this before we perform the null check,
2978 // because if the test is going to turn into zero code, we don't
2979 // want a residual null check left around. (Causes a slowdown,
2980 // for example, in some objArray manipulations, such as a[i]=a[j].)
2981 if (tk->singleton()) {
2982 const TypeOopPtr* objtp = _gvn.type(obj)->isa_oopptr();
2983 if (objtp != NULL && objtp->klass() != NULL) {
2984 switch (C->static_subtype_check(tk->klass(), objtp->klass())) {
2985 case Compile::SSC_always_true:
2986 // If we know the type check always succeed then we don't use
2987 // the profiling data at this bytecode. Don't lose it, feed it
2988 // to the type system as a speculative type.
2989 return record_profiled_receiver_for_speculation(obj);
2990 case Compile::SSC_always_false:
2991 // It needs a null check because a null will *pass* the cast check.
2992 // A non-null value will always produce an exception.
2993 return null_assert(obj);
2994 }
2995 }
2996 }
2997
2998 ciProfileData* data = NULL;
2999 bool safe_for_replace = false;
3000 if (failure_control == NULL) { // use MDO in regular case only
3001 assert(java_bc() == Bytecodes::_aastore ||
3002 java_bc() == Bytecodes::_checkcast,
3003 "interpreter profiles type checks only for these BCs");
3004 data = method()->method_data()->bci_to_data(bci());
3005 safe_for_replace = true;
3006 }
3007
3008 // Make the merge point
3009 enum { _obj_path = 1, _null_path, PATH_LIMIT };
3010 RegionNode* region = new RegionNode(PATH_LIMIT);
3011 Node* phi = new PhiNode(region, toop);
3012 C->set_has_split_ifs(true); // Has chance for split-if optimization
3013
3014 // Use null-cast information if it is available
3015 bool speculative_not_null = false;
3016 bool never_see_null = ((failure_control == NULL) // regular case only
3017 && seems_never_null(obj, data, speculative_not_null));
3018
3019 // Null check; get casted pointer; set region slot 3
3020 Node* null_ctl = top();
3021 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
3022
3023 // If not_null_obj is dead, only null-path is taken
3024 if (stopped()) { // Doing instance-of on a NULL?
3025 set_control(null_ctl);
3026 return null();
3027 }
3028 region->init_req(_null_path, null_ctl);
3029 phi ->init_req(_null_path, null()); // Set null path value
3030 if (null_ctl == top()) {
3031 // Do this eagerly, so that pattern matches like is_diamond_phi
3032 // will work even during parsing.
3033 assert(_null_path == PATH_LIMIT-1, "delete last");
3034 region->del_req(_null_path);
3035 phi ->del_req(_null_path);
3036 }
3037
3038 Node* cast_obj = NULL;
3039 if (tk->klass_is_exact()) {
3040 // The following optimization tries to statically cast the speculative type of the object
3041 // (for example obtained during profiling) to the type of the superklass and then do a
3042 // dynamic check that the type of the object is what we expect. To work correctly
3043 // for checkcast and aastore the type of superklass should be exact.
3044 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
3045 // We may not have profiling here or it may not help us. If we have
3046 // a speculative type use it to perform an exact cast.
3047 ciKlass* spec_obj_type = obj_type->speculative_type();
3048 if (spec_obj_type != NULL || data != NULL) {
3049 cast_obj = maybe_cast_profiled_receiver(not_null_obj, tk->klass(), spec_obj_type, safe_for_replace);
3050 if (cast_obj != NULL) {
3051 if (failure_control != NULL) // failure is now impossible
3052 (*failure_control) = top();
3053 // adjust the type of the phi to the exact klass:
3054 phi->raise_bottom_type(_gvn.type(cast_obj)->meet_speculative(TypePtr::NULL_PTR));
3055 }
3056 }
3057 }
3058
3059 if (cast_obj == NULL) {
3060 // Load the object's klass
3061 Node* obj_klass = load_object_klass(not_null_obj);
3062
3063 // Generate the subtype check
3064 Node* not_subtype_ctrl = gen_subtype_check( obj_klass, superklass );
3065
3066 // Plug in success path into the merge
3067 cast_obj = _gvn.transform(new CheckCastPPNode(control(), not_null_obj, toop));
3068 // Failure path ends in uncommon trap (or may be dead - failure impossible)
3069 if (failure_control == NULL) {
3070 if (not_subtype_ctrl != top()) { // If failure is possible
3071 PreserveJVMState pjvms(this);
3072 set_control(not_subtype_ctrl);
3073 builtin_throw(Deoptimization::Reason_class_check, obj_klass);
3074 }
3075 } else {
3076 (*failure_control) = not_subtype_ctrl;
3077 }
3078 }
3079
3080 region->init_req(_obj_path, control());
3081 phi ->init_req(_obj_path, cast_obj);
3082
3083 // A merge of NULL or Casted-NotNull obj
3084 Node* res = _gvn.transform(phi);
3085
3086 // Note I do NOT always 'replace_in_map(obj,result)' here.
3087 // if( tk->klass()->can_be_primary_super() )
3088 // This means that if I successfully store an Object into an array-of-String
3089 // I 'forget' that the Object is really now known to be a String. I have to
3090 // do this because we don't have true union types for interfaces - if I store
3091 // a Baz into an array-of-Interface and then tell the optimizer it's an
3092 // Interface, I forget that it's also a Baz and cannot do Baz-like field
3093 // references to it. FIX THIS WHEN UNION TYPES APPEAR!
3094 // replace_in_map( obj, res );
3095
3096 // Return final merged results
3097 set_control( _gvn.transform(region) );
3098 record_for_igvn(region);
3099 return res;
3100 }
3101
3102 //------------------------------next_monitor-----------------------------------
3103 // What number should be given to the next monitor?
3104 int GraphKit::next_monitor() {
3105 int current = jvms()->monitor_depth()* C->sync_stack_slots();
3106 int next = current + C->sync_stack_slots();
3107 // Keep the toplevel high water mark current:
3108 if (C->fixed_slots() < next) C->set_fixed_slots(next);
3109 return current;
3110 }
3111
3112 //------------------------------insert_mem_bar---------------------------------
3113 // Memory barrier to avoid floating things around
3114 // The membar serves as a pinch point between both control and all memory slices.
3115 Node* GraphKit::insert_mem_bar(int opcode, Node* precedent) {
3116 MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);
3117 mb->init_req(TypeFunc::Control, control());
3118 mb->init_req(TypeFunc::Memory, reset_memory());
3119 Node* membar = _gvn.transform(mb);
3120 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3121 set_all_memory_call(membar);
3122 return membar;
3123 }
3124
3125 //-------------------------insert_mem_bar_volatile----------------------------
3126 // Memory barrier to avoid floating things around
3127 // The membar serves as a pinch point between both control and memory(alias_idx).
3128 // If you want to make a pinch point on all memory slices, do not use this
3129 // function (even with AliasIdxBot); use insert_mem_bar() instead.
3130 Node* GraphKit::insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent) {
3131 // When Parse::do_put_xxx updates a volatile field, it appends a series
3132 // of MemBarVolatile nodes, one for *each* volatile field alias category.
3133 // The first membar is on the same memory slice as the field store opcode.
3134 // This forces the membar to follow the store. (Bug 6500685 broke this.)
3135 // All the other membars (for other volatile slices, including AliasIdxBot,
3136 // which stands for all unknown volatile slices) are control-dependent
3137 // on the first membar. This prevents later volatile loads or stores
3138 // from sliding up past the just-emitted store.
3139
3140 MemBarNode* mb = MemBarNode::make(C, opcode, alias_idx, precedent);
3141 mb->set_req(TypeFunc::Control,control());
3142 if (alias_idx == Compile::AliasIdxBot) {
3143 mb->set_req(TypeFunc::Memory, merged_memory()->base_memory());
3144 } else {
3145 assert(!(opcode == Op_Initialize && alias_idx != Compile::AliasIdxRaw), "fix caller");
3146 mb->set_req(TypeFunc::Memory, memory(alias_idx));
3147 }
3148 Node* membar = _gvn.transform(mb);
3149 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3150 if (alias_idx == Compile::AliasIdxBot) {
3151 merged_memory()->set_base_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)));
3152 } else {
3153 set_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)),alias_idx);
3154 }
3155 return membar;
3156 }
3157
3158 //------------------------------shared_lock------------------------------------
3159 // Emit locking code.
3160 FastLockNode* GraphKit::shared_lock(Node* obj) {
3161 // bci is either a monitorenter bc or InvocationEntryBci
3162 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3163 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3164
3165 if( !GenerateSynchronizationCode )
3166 return NULL; // Not locking things?
3167 if (stopped()) // Dead monitor?
3168 return NULL;
3169
3170 assert(dead_locals_are_killed(), "should kill locals before sync. point");
3171
3172 // Box the stack location
3173 Node* box = _gvn.transform(new BoxLockNode(next_monitor()));
3174 Node* mem = reset_memory();
3175
3176 FastLockNode * flock = _gvn.transform(new FastLockNode(0, obj, box) )->as_FastLock();
3177 if (UseBiasedLocking && PrintPreciseBiasedLockingStatistics) {
3178 // Create the counters for this fast lock.
3179 flock->create_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3180 }
3181
3182 // Create the rtm counters for this fast lock if needed.
3183 flock->create_rtm_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3184
3185 // Add monitor to debug info for the slow path. If we block inside the
3186 // slow path and de-opt, we need the monitor hanging around
3187 map()->push_monitor( flock );
3188
3189 const TypeFunc *tf = LockNode::lock_type();
3190 LockNode *lock = new LockNode(C, tf);
3191
3192 lock->init_req( TypeFunc::Control, control() );
3193 lock->init_req( TypeFunc::Memory , mem );
3194 lock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3195 lock->init_req( TypeFunc::FramePtr, frameptr() );
3196 lock->init_req( TypeFunc::ReturnAdr, top() );
3197
3198 lock->init_req(TypeFunc::Parms + 0, obj);
3199 lock->init_req(TypeFunc::Parms + 1, box);
3200 lock->init_req(TypeFunc::Parms + 2, flock);
3201 add_safepoint_edges(lock);
3202
3203 lock = _gvn.transform( lock )->as_Lock();
3204
3205 // lock has no side-effects, sets few values
3206 set_predefined_output_for_runtime_call(lock, mem, TypeRawPtr::BOTTOM);
3207
3208 insert_mem_bar(Op_MemBarAcquireLock);
3209
3210 // Add this to the worklist so that the lock can be eliminated
3211 record_for_igvn(lock);
3212
3213 #ifndef PRODUCT
3214 if (PrintLockStatistics) {
3215 // Update the counter for this lock. Don't bother using an atomic
3216 // operation since we don't require absolute accuracy.
3217 lock->create_lock_counter(map()->jvms());
3218 increment_counter(lock->counter()->addr());
3219 }
3220 #endif
3221
3222 return flock;
3223 }
3224
3225
3226 //------------------------------shared_unlock----------------------------------
3227 // Emit unlocking code.
3228 void GraphKit::shared_unlock(Node* box, Node* obj) {
3229 // bci is either a monitorenter bc or InvocationEntryBci
3230 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3231 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3232
3233 if( !GenerateSynchronizationCode )
3234 return;
3235 if (stopped()) { // Dead monitor?
3236 map()->pop_monitor(); // Kill monitor from debug info
3237 return;
3238 }
3239
3240 // Memory barrier to avoid floating things down past the locked region
3241 insert_mem_bar(Op_MemBarReleaseLock);
3242
3243 const TypeFunc *tf = OptoRuntime::complete_monitor_exit_Type();
3244 UnlockNode *unlock = new UnlockNode(C, tf);
3245 #ifdef ASSERT
3246 unlock->set_dbg_jvms(sync_jvms());
3247 #endif
3248 uint raw_idx = Compile::AliasIdxRaw;
3249 unlock->init_req( TypeFunc::Control, control() );
3250 unlock->init_req( TypeFunc::Memory , memory(raw_idx) );
3251 unlock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3252 unlock->init_req( TypeFunc::FramePtr, frameptr() );
3253 unlock->init_req( TypeFunc::ReturnAdr, top() );
3254
3255 unlock->init_req(TypeFunc::Parms + 0, obj);
3256 unlock->init_req(TypeFunc::Parms + 1, box);
3257 unlock = _gvn.transform(unlock)->as_Unlock();
3258
3259 Node* mem = reset_memory();
3260
3261 // unlock has no side-effects, sets few values
3262 set_predefined_output_for_runtime_call(unlock, mem, TypeRawPtr::BOTTOM);
3263
3264 // Kill monitor from debug info
3265 map()->pop_monitor( );
3266 }
3267
3268 //-------------------------------get_layout_helper-----------------------------
3269 // If the given klass is a constant or known to be an array,
3270 // fetch the constant layout helper value into constant_value
3271 // and return (Node*)NULL. Otherwise, load the non-constant
3272 // layout helper value, and return the node which represents it.
3273 // This two-faced routine is useful because allocation sites
3274 // almost always feature constant types.
3275 Node* GraphKit::get_layout_helper(Node* klass_node, jint& constant_value) {
3276 const TypeKlassPtr* inst_klass = _gvn.type(klass_node)->isa_klassptr();
3277 if (!StressReflectiveCode && inst_klass != NULL) {
3278 ciKlass* klass = inst_klass->klass();
3279 bool xklass = inst_klass->klass_is_exact();
3280 if (xklass || klass->is_array_klass()) {
3281 jint lhelper = klass->layout_helper();
3282 if (lhelper != Klass::_lh_neutral_value) {
3283 constant_value = lhelper;
3284 return (Node*) NULL;
3285 }
3286 }
3287 }
3288 constant_value = Klass::_lh_neutral_value; // put in a known value
3289 Node* lhp = basic_plus_adr(klass_node, klass_node, in_bytes(Klass::layout_helper_offset()));
3290 return make_load(NULL, lhp, TypeInt::INT, T_INT, MemNode::unordered);
3291 }
3292
3293 // We just put in an allocate/initialize with a big raw-memory effect.
3294 // Hook selected additional alias categories on the initialization.
3295 static void hook_memory_on_init(GraphKit& kit, int alias_idx,
3296 MergeMemNode* init_in_merge,
3297 Node* init_out_raw) {
3298 DEBUG_ONLY(Node* init_in_raw = init_in_merge->base_memory());
3299 assert(init_in_merge->memory_at(alias_idx) == init_in_raw, "");
3300
3301 Node* prevmem = kit.memory(alias_idx);
3302 init_in_merge->set_memory_at(alias_idx, prevmem);
3303 kit.set_memory(init_out_raw, alias_idx);
3304 }
3305
3306 //---------------------------set_output_for_allocation-------------------------
3307 Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
3308 const TypeOopPtr* oop_type,
3309 bool deoptimize_on_exception) {
3310 int rawidx = Compile::AliasIdxRaw;
3311 alloc->set_req( TypeFunc::FramePtr, frameptr() );
3312 add_safepoint_edges(alloc);
3313 Node* allocx = _gvn.transform(alloc);
3314 set_control( _gvn.transform(new ProjNode(allocx, TypeFunc::Control) ) );
3315 // create memory projection for i_o
3316 set_memory ( _gvn.transform( new ProjNode(allocx, TypeFunc::Memory, true) ), rawidx );
3317 make_slow_call_ex(allocx, env()->Throwable_klass(), true, deoptimize_on_exception);
3318
3319 // create a memory projection as for the normal control path
3320 Node* malloc = _gvn.transform(new ProjNode(allocx, TypeFunc::Memory));
3321 set_memory(malloc, rawidx);
3322
3323 // a normal slow-call doesn't change i_o, but an allocation does
3324 // we create a separate i_o projection for the normal control path
3325 set_i_o(_gvn.transform( new ProjNode(allocx, TypeFunc::I_O, false) ) );
3326 Node* rawoop = _gvn.transform( new ProjNode(allocx, TypeFunc::Parms) );
3327
3328 // put in an initialization barrier
3329 InitializeNode* init = insert_mem_bar_volatile(Op_Initialize, rawidx,
3330 rawoop)->as_Initialize();
3331 assert(alloc->initialization() == init, "2-way macro link must work");
3332 assert(init ->allocation() == alloc, "2-way macro link must work");
3333 {
3334 // Extract memory strands which may participate in the new object's
3335 // initialization, and source them from the new InitializeNode.
3336 // This will allow us to observe initializations when they occur,
3337 // and link them properly (as a group) to the InitializeNode.
3338 assert(init->in(InitializeNode::Memory) == malloc, "");
3339 MergeMemNode* minit_in = MergeMemNode::make(malloc);
3340 init->set_req(InitializeNode::Memory, minit_in);
3341 record_for_igvn(minit_in); // fold it up later, if possible
3342 Node* minit_out = memory(rawidx);
3343 assert(minit_out->is_Proj() && minit_out->in(0) == init, "");
3344 if (oop_type->isa_aryptr()) {
3345 const TypePtr* telemref = oop_type->add_offset(Type::OffsetBot);
3346 int elemidx = C->get_alias_index(telemref);
3347 hook_memory_on_init(*this, elemidx, minit_in, minit_out);
3348 } else if (oop_type->isa_instptr()) {
3349 ciInstanceKlass* ik = oop_type->klass()->as_instance_klass();
3350 for (int i = 0, len = ik->nof_nonstatic_fields(); i < len; i++) {
3351 ciField* field = ik->nonstatic_field_at(i);
3352 if (field->offset() >= TrackedInitializationLimit * HeapWordSize)
3353 continue; // do not bother to track really large numbers of fields
3354 // Find (or create) the alias category for this field:
3355 int fieldidx = C->alias_type(field)->index();
3356 hook_memory_on_init(*this, fieldidx, minit_in, minit_out);
3357 }
3358 }
3359 }
3360
3361 // Cast raw oop to the real thing...
3362 Node* javaoop = new CheckCastPPNode(control(), rawoop, oop_type);
3363 javaoop = _gvn.transform(javaoop);
3364 C->set_recent_alloc(control(), javaoop);
3365 assert(just_allocated_object(control()) == javaoop, "just allocated");
3366
3367 #ifdef ASSERT
3368 { // Verify that the AllocateNode::Ideal_allocation recognizers work:
3369 assert(AllocateNode::Ideal_allocation(rawoop, &_gvn) == alloc,
3370 "Ideal_allocation works");
3371 assert(AllocateNode::Ideal_allocation(javaoop, &_gvn) == alloc,
3372 "Ideal_allocation works");
3373 if (alloc->is_AllocateArray()) {
3374 assert(AllocateArrayNode::Ideal_array_allocation(rawoop, &_gvn) == alloc->as_AllocateArray(),
3375 "Ideal_allocation works");
3376 assert(AllocateArrayNode::Ideal_array_allocation(javaoop, &_gvn) == alloc->as_AllocateArray(),
3377 "Ideal_allocation works");
3378 } else {
3379 assert(alloc->in(AllocateNode::ALength)->is_top(), "no length, please");
3380 }
3381 }
3382 #endif //ASSERT
3383
3384 return javaoop;
3385 }
3386
3387 //---------------------------new_instance--------------------------------------
3388 // This routine takes a klass_node which may be constant (for a static type)
3389 // or may be non-constant (for reflective code). It will work equally well
3390 // for either, and the graph will fold nicely if the optimizer later reduces
3391 // the type to a constant.
3392 // The optional arguments are for specialized use by intrinsics:
3393 // - If 'extra_slow_test' if not null is an extra condition for the slow-path.
3394 // - If 'return_size_val', report the the total object size to the caller.
3395 // - deoptimize_on_exception controls how Java exceptions are handled (rethrow vs deoptimize)
3396 Node* GraphKit::new_instance(Node* klass_node,
3397 Node* extra_slow_test,
3398 Node* *return_size_val,
3399 bool deoptimize_on_exception) {
3400 // Compute size in doublewords
3401 // The size is always an integral number of doublewords, represented
3402 // as a positive bytewise size stored in the klass's layout_helper.
3403 // The layout_helper also encodes (in a low bit) the need for a slow path.
3404 jint layout_con = Klass::_lh_neutral_value;
3405 Node* layout_val = get_layout_helper(klass_node, layout_con);
3406 int layout_is_con = (layout_val == NULL);
3407
3408 if (extra_slow_test == NULL) extra_slow_test = intcon(0);
3409 // Generate the initial go-slow test. It's either ALWAYS (return a
3410 // Node for 1) or NEVER (return a NULL) or perhaps (in the reflective
3411 // case) a computed value derived from the layout_helper.
3412 Node* initial_slow_test = NULL;
3413 if (layout_is_con) {
3414 assert(!StressReflectiveCode, "stress mode does not use these paths");
3415 bool must_go_slow = Klass::layout_helper_needs_slow_path(layout_con);
3416 initial_slow_test = must_go_slow? intcon(1): extra_slow_test;
3417
3418 } else { // reflective case
3419 // This reflective path is used by Unsafe.allocateInstance.
3420 // (It may be stress-tested by specifying StressReflectiveCode.)
3421 // Basically, we want to get into the VM is there's an illegal argument.
3422 Node* bit = intcon(Klass::_lh_instance_slow_path_bit);
3423 initial_slow_test = _gvn.transform( new AndINode(layout_val, bit) );
3424 if (extra_slow_test != intcon(0)) {
3425 initial_slow_test = _gvn.transform( new OrINode(initial_slow_test, extra_slow_test) );
3426 }
3427 // (Macro-expander will further convert this to a Bool, if necessary.)
3428 }
3429
3430 // Find the size in bytes. This is easy; it's the layout_helper.
3431 // The size value must be valid even if the slow path is taken.
3432 Node* size = NULL;
3433 if (layout_is_con) {
3434 size = MakeConX(Klass::layout_helper_size_in_bytes(layout_con));
3435 } else { // reflective case
3436 // This reflective path is used by clone and Unsafe.allocateInstance.
3437 size = ConvI2X(layout_val);
3438
3439 // Clear the low bits to extract layout_helper_size_in_bytes:
3440 assert((int)Klass::_lh_instance_slow_path_bit < BytesPerLong, "clear bit");
3441 Node* mask = MakeConX(~ (intptr_t)right_n_bits(LogBytesPerLong));
3442 size = _gvn.transform( new AndXNode(size, mask) );
3443 }
3444 if (return_size_val != NULL) {
3445 (*return_size_val) = size;
3446 }
3447
3448 // This is a precise notnull oop of the klass.
3449 // (Actually, it need not be precise if this is a reflective allocation.)
3450 // It's what we cast the result to.
3451 const TypeKlassPtr* tklass = _gvn.type(klass_node)->isa_klassptr();
3452 if (!tklass) tklass = TypeKlassPtr::OBJECT;
3453 const TypeOopPtr* oop_type = tklass->as_instance_type();
3454
3455 // Now generate allocation code
3456
3457 // The entire memory state is needed for slow path of the allocation
3458 // since GC and deoptimization can happened.
3459 Node *mem = reset_memory();
3460 set_all_memory(mem); // Create new memory state
3461
3462 AllocateNode* alloc = new AllocateNode(C, AllocateNode::alloc_type(Type::TOP),
3463 control(), mem, i_o(),
3464 size, klass_node,
3465 initial_slow_test);
3466
3467 return set_output_for_allocation(alloc, oop_type, deoptimize_on_exception);
3468 }
3469
3470 //-------------------------------new_array-------------------------------------
3471 // helper for both newarray and anewarray
3472 // The 'length' parameter is (obviously) the length of the array.
3473 // See comments on new_instance for the meaning of the other arguments.
3474 Node* GraphKit::new_array(Node* klass_node, // array klass (maybe variable)
3475 Node* length, // number of array elements
3476 int nargs, // number of arguments to push back for uncommon trap
3477 Node* *return_size_val,
3478 bool deoptimize_on_exception) {
3479 jint layout_con = Klass::_lh_neutral_value;
3480 Node* layout_val = get_layout_helper(klass_node, layout_con);
3481 int layout_is_con = (layout_val == NULL);
3482
3483 if (!layout_is_con && !StressReflectiveCode &&
3484 !too_many_traps(Deoptimization::Reason_class_check)) {
3485 // This is a reflective array creation site.
3486 // Optimistically assume that it is a subtype of Object[],
3487 // so that we can fold up all the address arithmetic.
3488 layout_con = Klass::array_layout_helper(T_OBJECT);
3489 Node* cmp_lh = _gvn.transform( new CmpINode(layout_val, intcon(layout_con)) );
3490 Node* bol_lh = _gvn.transform( new BoolNode(cmp_lh, BoolTest::eq) );
3491 { BuildCutout unless(this, bol_lh, PROB_MAX);
3492 inc_sp(nargs);
3493 uncommon_trap(Deoptimization::Reason_class_check,
3494 Deoptimization::Action_maybe_recompile);
3495 }
3496 layout_val = NULL;
3497 layout_is_con = true;
3498 }
3499
3500 // Generate the initial go-slow test. Make sure we do not overflow
3501 // if length is huge (near 2Gig) or negative! We do not need
3502 // exact double-words here, just a close approximation of needed
3503 // double-words. We can't add any offset or rounding bits, lest we
3504 // take a size -1 of bytes and make it positive. Use an unsigned
3505 // compare, so negative sizes look hugely positive.
3506 int fast_size_limit = FastAllocateSizeLimit;
3507 if (layout_is_con) {
3508 assert(!StressReflectiveCode, "stress mode does not use these paths");
3509 // Increase the size limit if we have exact knowledge of array type.
3510 int log2_esize = Klass::layout_helper_log2_element_size(layout_con);
3511 fast_size_limit <<= (LogBytesPerLong - log2_esize);
3512 }
3513
3514 Node* initial_slow_cmp = _gvn.transform( new CmpUNode( length, intcon( fast_size_limit ) ) );
3515 Node* initial_slow_test = _gvn.transform( new BoolNode( initial_slow_cmp, BoolTest::gt ) );
3516 if (initial_slow_test->is_Bool()) {
3517 // Hide it behind a CMoveI, or else PhaseIdealLoop::split_up will get sick.
3518 initial_slow_test = initial_slow_test->as_Bool()->as_int_value(&_gvn);
3519 }
3520
3521 // --- Size Computation ---
3522 // array_size = round_to_heap(array_header + (length << elem_shift));
3523 // where round_to_heap(x) == round_to(x, MinObjAlignmentInBytes)
3524 // and round_to(x, y) == ((x + y-1) & ~(y-1))
3525 // The rounding mask is strength-reduced, if possible.
3526 int round_mask = MinObjAlignmentInBytes - 1;
3527 Node* header_size = NULL;
3528 int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
3529 // (T_BYTE has the weakest alignment and size restrictions...)
3530 if (layout_is_con) {
3531 int hsize = Klass::layout_helper_header_size(layout_con);
3532 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3533 BasicType etype = Klass::layout_helper_element_type(layout_con);
3534 if ((round_mask & ~right_n_bits(eshift)) == 0)
3535 round_mask = 0; // strength-reduce it if it goes away completely
3536 assert((hsize & right_n_bits(eshift)) == 0, "hsize is pre-rounded");
3537 assert(header_size_min <= hsize, "generic minimum is smallest");
3538 header_size_min = hsize;
3539 header_size = intcon(hsize + round_mask);
3540 } else {
3541 Node* hss = intcon(Klass::_lh_header_size_shift);
3542 Node* hsm = intcon(Klass::_lh_header_size_mask);
3543 Node* hsize = _gvn.transform( new URShiftINode(layout_val, hss) );
3544 hsize = _gvn.transform( new AndINode(hsize, hsm) );
3545 Node* mask = intcon(round_mask);
3546 header_size = _gvn.transform( new AddINode(hsize, mask) );
3547 }
3548
3549 Node* elem_shift = NULL;
3550 if (layout_is_con) {
3551 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3552 if (eshift != 0)
3553 elem_shift = intcon(eshift);
3554 } else {
3555 // There is no need to mask or shift this value.
3556 // The semantics of LShiftINode include an implicit mask to 0x1F.
3557 assert(Klass::_lh_log2_element_size_shift == 0, "use shift in place");
3558 elem_shift = layout_val;
3559 }
3560
3561 // Transition to native address size for all offset calculations:
3562 Node* lengthx = ConvI2X(length);
3563 Node* headerx = ConvI2X(header_size);
3564 #ifdef _LP64
3565 { const TypeLong* tllen = _gvn.find_long_type(lengthx);
3566 if (tllen != NULL && tllen->_lo < 0) {
3567 // Add a manual constraint to a positive range. Cf. array_element_address.
3568 jlong size_max = arrayOopDesc::max_array_length(T_BYTE);
3569 if (size_max > tllen->_hi) size_max = tllen->_hi;
3570 const TypeLong* tlcon = TypeLong::make(CONST64(0), size_max, Type::WidenMin);
3571 lengthx = _gvn.transform( new ConvI2LNode(length, tlcon));
3572 }
3573 }
3574 #endif
3575
3576 // Combine header size (plus rounding) and body size. Then round down.
3577 // This computation cannot overflow, because it is used only in two
3578 // places, one where the length is sharply limited, and the other
3579 // after a successful allocation.
3580 Node* abody = lengthx;
3581 if (elem_shift != NULL)
3582 abody = _gvn.transform( new LShiftXNode(lengthx, elem_shift) );
3583 Node* size = _gvn.transform( new AddXNode(headerx, abody) );
3584 if (round_mask != 0) {
3585 Node* mask = MakeConX(~round_mask);
3586 size = _gvn.transform( new AndXNode(size, mask) );
3587 }
3588 // else if round_mask == 0, the size computation is self-rounding
3589
3590 if (return_size_val != NULL) {
3591 // This is the size
3592 (*return_size_val) = size;
3593 }
3594
3595 // Now generate allocation code
3596
3597 // The entire memory state is needed for slow path of the allocation
3598 // since GC and deoptimization can happened.
3599 Node *mem = reset_memory();
3600 set_all_memory(mem); // Create new memory state
3601
3602 // Create the AllocateArrayNode and its result projections
3603 AllocateArrayNode* alloc
3604 = new AllocateArrayNode(C, AllocateArrayNode::alloc_type(TypeInt::INT),
3605 control(), mem, i_o(),
3606 size, klass_node,
3607 initial_slow_test,
3608 length);
3609
3610 // Cast to correct type. Note that the klass_node may be constant or not,
3611 // and in the latter case the actual array type will be inexact also.
3612 // (This happens via a non-constant argument to inline_native_newArray.)
3613 // In any case, the value of klass_node provides the desired array type.
3614 const TypeInt* length_type = _gvn.find_int_type(length);
3615 const TypeOopPtr* ary_type = _gvn.type(klass_node)->is_klassptr()->as_instance_type();
3616 if (ary_type->isa_aryptr() && length_type != NULL) {
3617 // Try to get a better type than POS for the size
3618 ary_type = ary_type->is_aryptr()->cast_to_size(length_type);
3619 }
3620
3621 Node* javaoop = set_output_for_allocation(alloc, ary_type, deoptimize_on_exception);
3622
3623 // Cast length on remaining path to be as narrow as possible
3624 if (map()->find_edge(length) >= 0) {
3625 Node* ccast = alloc->make_ideal_length(ary_type, &_gvn);
3626 if (ccast != length) {
3627 _gvn.set_type_bottom(ccast);
3628 record_for_igvn(ccast);
3629 replace_in_map(length, ccast);
3630 }
3631 }
3632
3633 return javaoop;
3634 }
3635
3636 // The following "Ideal_foo" functions are placed here because they recognize
3637 // the graph shapes created by the functions immediately above.
3638
3639 //---------------------------Ideal_allocation----------------------------------
3640 // Given an oop pointer or raw pointer, see if it feeds from an AllocateNode.
3641 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase) {
3642 if (ptr == NULL) { // reduce dumb test in callers
3643 return NULL;
3644 }
3645 if (ptr->is_CheckCastPP()) { // strip only one raw-to-oop cast
3646 ptr = ptr->in(1);
3647 if (ptr == NULL) return NULL;
3648 }
3649 // Return NULL for allocations with several casts:
3650 // j.l.reflect.Array.newInstance(jobject, jint)
3651 // Object.clone()
3652 // to keep more precise type from last cast.
3653 if (ptr->is_Proj()) {
3654 Node* allo = ptr->in(0);
3655 if (allo != NULL && allo->is_Allocate()) {
3656 return allo->as_Allocate();
3657 }
3658 }
3659 // Report failure to match.
3660 return NULL;
3661 }
3662
3663 // Fancy version which also strips off an offset (and reports it to caller).
3664 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase,
3665 intptr_t& offset) {
3666 Node* base = AddPNode::Ideal_base_and_offset(ptr, phase, offset);
3667 if (base == NULL) return NULL;
3668 return Ideal_allocation(base, phase);
3669 }
3670
3671 // Trace Initialize <- Proj[Parm] <- Allocate
3672 AllocateNode* InitializeNode::allocation() {
3673 Node* rawoop = in(InitializeNode::RawAddress);
3674 if (rawoop->is_Proj()) {
3675 Node* alloc = rawoop->in(0);
3676 if (alloc->is_Allocate()) {
3677 return alloc->as_Allocate();
3678 }
3679 }
3680 return NULL;
3681 }
3682
3683 // Trace Allocate -> Proj[Parm] -> Initialize
3684 InitializeNode* AllocateNode::initialization() {
3685 ProjNode* rawoop = proj_out(AllocateNode::RawAddress);
3686 if (rawoop == NULL) return NULL;
3687 for (DUIterator_Fast imax, i = rawoop->fast_outs(imax); i < imax; i++) {
3688 Node* init = rawoop->fast_out(i);
3689 if (init->is_Initialize()) {
3690 assert(init->as_Initialize()->allocation() == this, "2-way link");
3691 return init->as_Initialize();
3692 }
3693 }
3694 return NULL;
3695 }
3696
3697 //----------------------------- loop predicates ---------------------------
3698
3699 //------------------------------add_predicate_impl----------------------------
3700 void GraphKit::add_predicate_impl(Deoptimization::DeoptReason reason, int nargs) {
3701 // Too many traps seen?
3702 if (too_many_traps(reason)) {
3703 #ifdef ASSERT
3704 if (TraceLoopPredicate) {
3705 int tc = C->trap_count(reason);
3706 tty->print("too many traps=%s tcount=%d in ",
3707 Deoptimization::trap_reason_name(reason), tc);
3708 method()->print(); // which method has too many predicate traps
3709 tty->cr();
3710 }
3711 #endif
3712 // We cannot afford to take more traps here,
3713 // do not generate predicate.
3714 return;
3715 }
3716
3717 Node *cont = _gvn.intcon(1);
3718 Node* opq = _gvn.transform(new Opaque1Node(C, cont));
3719 Node *bol = _gvn.transform(new Conv2BNode(opq));
3720 IfNode* iff = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
3721 Node* iffalse = _gvn.transform(new IfFalseNode(iff));
3722 C->add_predicate_opaq(opq);
3723 {
3724 PreserveJVMState pjvms(this);
3725 set_control(iffalse);
3726 inc_sp(nargs);
3727 uncommon_trap(reason, Deoptimization::Action_maybe_recompile);
3728 }
3729 Node* iftrue = _gvn.transform(new IfTrueNode(iff));
3730 set_control(iftrue);
3731 }
3732
3733 //------------------------------add_predicate---------------------------------
3734 void GraphKit::add_predicate(int nargs) {
3735 if (UseLoopPredicate) {
3736 add_predicate_impl(Deoptimization::Reason_predicate, nargs);
3737 }
3738 // loop's limit check predicate should be near the loop.
3739 if (LoopLimitCheck) {
3740 add_predicate_impl(Deoptimization::Reason_loop_limit_check, nargs);
3741 }
3742 }
3743
3744 //----------------------------- store barriers ----------------------------
3745 #define __ ideal.
3746
3747 void GraphKit::sync_kit(IdealKit& ideal) {
3748 set_all_memory(__ merged_memory());
3749 set_i_o(__ i_o());
3750 set_control(__ ctrl());
3751 }
3752
3753 void GraphKit::final_sync(IdealKit& ideal) {
3754 // Final sync IdealKit and graphKit.
3755 sync_kit(ideal);
3756 }
3757
3758 Node* GraphKit::byte_map_base_node() {
3759 // Get base of card map
3760 CardTableModRefBS* ct =
3761 barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
3762 assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust users of this code");
3763 if (ct->byte_map_base != NULL) {
3764 return makecon(TypeRawPtr::make((address)ct->byte_map_base));
3765 } else {
3766 return null();
3767 }
3768 }
3769
3770 // vanilla/CMS post barrier
3771 // Insert a write-barrier store. This is to let generational GC work; we have
3772 // to flag all oop-stores before the next GC point.
3773 void GraphKit::write_barrier_post(Node* oop_store,
3774 Node* obj,
3775 Node* adr,
3776 uint adr_idx,
3777 Node* val,
3778 bool use_precise) {
3779 // No store check needed if we're storing a NULL or an old object
3780 // (latter case is probably a string constant). The concurrent
3781 // mark sweep garbage collector, however, needs to have all nonNull
3782 // oop updates flagged via card-marks.
3783 if (val != NULL && val->is_Con()) {
3784 // must be either an oop or NULL
3785 const Type* t = val->bottom_type();
3786 if (t == TypePtr::NULL_PTR || t == Type::TOP)
3787 // stores of null never (?) need barriers
3788 return;
3789 }
3790
3791 if (use_ReduceInitialCardMarks()
3792 && obj == just_allocated_object(control())) {
3793 // We can skip marks on a freshly-allocated object in Eden.
3794 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
3795 // That routine informs GC to take appropriate compensating steps,
3796 // upon a slow-path allocation, so as to make this card-mark
3797 // elision safe.
3798 return;
3799 }
3800
3801 if (!use_precise) {
3802 // All card marks for a (non-array) instance are in one place:
3803 adr = obj;
3804 }
3805 // (Else it's an array (or unknown), and we want more precise card marks.)
3806 assert(adr != NULL, "");
3807
3808 IdealKit ideal(this, true);
3809
3810 // Convert the pointer to an int prior to doing math on it
3811 Node* cast = __ CastPX(__ ctrl(), adr);
3812
3813 // Divide by card size
3814 assert(Universe::heap()->barrier_set()->is_a(BarrierSet::CardTableModRef),
3815 "Only one we handle so far.");
3816 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
3817
3818 // Combine card table base and card offset
3819 Node* card_adr = __ AddP(__ top(), byte_map_base_node(), card_offset );
3820
3821 // Get the alias_index for raw card-mark memory
3822 int adr_type = Compile::AliasIdxRaw;
3823 Node* zero = __ ConI(0); // Dirty card value
3824 BasicType bt = T_BYTE;
3825
3826 if (UseConcMarkSweepGC && UseCondCardMark) {
3827 insert_mem_bar(Op_MemBarVolatile); // StoreLoad barrier
3828 __ sync_kit(this);
3829 }
3830
3831 if (UseCondCardMark) {
3832 // The classic GC reference write barrier is typically implemented
3833 // as a store into the global card mark table. Unfortunately
3834 // unconditional stores can result in false sharing and excessive
3835 // coherence traffic as well as false transactional aborts.
3836 // UseCondCardMark enables MP "polite" conditional card mark
3837 // stores. In theory we could relax the load from ctrl() to
3838 // no_ctrl, but that doesn't buy much latitude.
3839 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, bt, adr_type);
3840 __ if_then(card_val, BoolTest::ne, zero);
3841 }
3842
3843 // Smash zero into card
3844 if( !UseConcMarkSweepGC ) {
3845 __ store(__ ctrl(), card_adr, zero, bt, adr_type, MemNode::unordered);
3846 } else {
3847 // Specialized path for CM store barrier
3848 __ storeCM(__ ctrl(), card_adr, zero, oop_store, adr_idx, bt, adr_type);
3849 }
3850
3851 if (UseCondCardMark) {
3852 __ end_if();
3853 }
3854
3855 // Final sync IdealKit and GraphKit.
3856 final_sync(ideal);
3857 }
3858 /*
3859 * Determine if the G1 pre-barrier can be removed. The pre-barrier is
3860 * required by SATB to make sure all objects live at the start of the
3861 * marking are kept alive, all reference updates need to any previous
3862 * reference stored before writing.
3863 *
3864 * If the previous value is NULL there is no need to save the old value.
3865 * References that are NULL are filtered during runtime by the barrier
3866 * code to avoid unnecessary queuing.
3867 *
3868 * However in the case of newly allocated objects it might be possible to
3869 * prove that the reference about to be overwritten is NULL during compile
3870 * time and avoid adding the barrier code completely.
3871 *
3872 * The compiler needs to determine that the object in which a field is about
3873 * to be written is newly allocated, and that no prior store to the same field
3874 * has happened since the allocation.
3875 *
3876 * Returns true if the pre-barrier can be removed
3877 */
3878 bool GraphKit::g1_can_remove_pre_barrier(PhaseTransform* phase, Node* adr,
3879 BasicType bt, uint adr_idx) {
3880 intptr_t offset = 0;
3881 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
3882 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
3883
3884 if (offset == Type::OffsetBot) {
3885 return false; // cannot unalias unless there are precise offsets
3886 }
3887
3888 if (alloc == NULL) {
3889 return false; // No allocation found
3890 }
3891
3892 intptr_t size_in_bytes = type2aelembytes(bt);
3893
3894 Node* mem = memory(adr_idx); // start searching here...
3895
3896 for (int cnt = 0; cnt < 50; cnt++) {
3897
3898 if (mem->is_Store()) {
3899
3900 Node* st_adr = mem->in(MemNode::Address);
3901 intptr_t st_offset = 0;
3902 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
3903
3904 if (st_base == NULL) {
3905 break; // inscrutable pointer
3906 }
3907
3908 // Break we have found a store with same base and offset as ours so break
3909 if (st_base == base && st_offset == offset) {
3910 break;
3911 }
3912
3913 if (st_offset != offset && st_offset != Type::OffsetBot) {
3914 const int MAX_STORE = BytesPerLong;
3915 if (st_offset >= offset + size_in_bytes ||
3916 st_offset <= offset - MAX_STORE ||
3917 st_offset <= offset - mem->as_Store()->memory_size()) {
3918 // Success: The offsets are provably independent.
3919 // (You may ask, why not just test st_offset != offset and be done?
3920 // The answer is that stores of different sizes can co-exist
3921 // in the same sequence of RawMem effects. We sometimes initialize
3922 // a whole 'tile' of array elements with a single jint or jlong.)
3923 mem = mem->in(MemNode::Memory);
3924 continue; // advance through independent store memory
3925 }
3926 }
3927
3928 if (st_base != base
3929 && MemNode::detect_ptr_independence(base, alloc, st_base,
3930 AllocateNode::Ideal_allocation(st_base, phase),
3931 phase)) {
3932 // Success: The bases are provably independent.
3933 mem = mem->in(MemNode::Memory);
3934 continue; // advance through independent store memory
3935 }
3936 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
3937
3938 InitializeNode* st_init = mem->in(0)->as_Initialize();
3939 AllocateNode* st_alloc = st_init->allocation();
3940
3941 // Make sure that we are looking at the same allocation site.
3942 // The alloc variable is guaranteed to not be null here from earlier check.
3943 if (alloc == st_alloc) {
3944 // Check that the initialization is storing NULL so that no previous store
3945 // has been moved up and directly write a reference
3946 Node* captured_store = st_init->find_captured_store(offset,
3947 type2aelembytes(T_OBJECT),
3948 phase);
3949 if (captured_store == NULL || captured_store == st_init->zero_memory()) {
3950 return true;
3951 }
3952 }
3953 }
3954
3955 // Unless there is an explicit 'continue', we must bail out here,
3956 // because 'mem' is an inscrutable memory state (e.g., a call).
3957 break;
3958 }
3959
3960 return false;
3961 }
3962
3963 // G1 pre/post barriers
3964 void GraphKit::g1_write_barrier_pre(bool do_load,
3965 Node* obj,
3966 Node* adr,
3967 uint alias_idx,
3968 Node* val,
3969 const TypeOopPtr* val_type,
3970 Node* pre_val,
3971 BasicType bt) {
3972
3973 // Some sanity checks
3974 // Note: val is unused in this routine.
3975
3976 if (do_load) {
3977 // We need to generate the load of the previous value
3978 assert(obj != NULL, "must have a base");
3979 assert(adr != NULL, "where are loading from?");
3980 assert(pre_val == NULL, "loaded already?");
3981 assert(val_type != NULL, "need a type");
3982
3983 if (use_ReduceInitialCardMarks()
3984 && g1_can_remove_pre_barrier(&_gvn, adr, bt, alias_idx)) {
3985 return;
3986 }
3987
3988 } else {
3989 // In this case both val_type and alias_idx are unused.
3990 assert(pre_val != NULL, "must be loaded already");
3991 // Nothing to be done if pre_val is null.
3992 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
3993 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
3994 }
3995 assert(bt == T_OBJECT, "or we shouldn't be here");
3996
3997 IdealKit ideal(this, true);
3998
3999 Node* tls = __ thread(); // ThreadLocalStorage
4000
4001 Node* no_ctrl = NULL;
4002 Node* no_base = __ top();
4003 Node* zero = __ ConI(0);
4004 Node* zeroX = __ ConX(0);
4005
4006 float likely = PROB_LIKELY(0.999);
4007 float unlikely = PROB_UNLIKELY(0.999);
4008
4009 BasicType active_type = in_bytes(PtrQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE;
4010 assert(in_bytes(PtrQueue::byte_width_of_active()) == 4 || in_bytes(PtrQueue::byte_width_of_active()) == 1, "flag width");
4011
4012 // Offsets into the thread
4013 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 648
4014 PtrQueue::byte_offset_of_active());
4015 const int index_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 656
4016 PtrQueue::byte_offset_of_index());
4017 const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
4018 PtrQueue::byte_offset_of_buf());
4019
4020 // Now the actual pointers into the thread
4021 Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
4022 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4023 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4024
4025 // Now some of the values
4026 Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
4027
4028 // if (!marking)
4029 __ if_then(marking, BoolTest::ne, zero, unlikely); {
4030 BasicType index_bt = TypeX_X->basic_type();
4031 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 PtrQueue::_index with wrong size.");
4032 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
4033
4034 if (do_load) {
4035 // load original value
4036 // alias_idx correct??
4037 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
4038 }
4039
4040 // if (pre_val != NULL)
4041 __ if_then(pre_val, BoolTest::ne, null()); {
4042 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4043
4044 // is the queue for this thread full?
4045 __ if_then(index, BoolTest::ne, zeroX, likely); {
4046
4047 // decrement the index
4048 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4049
4050 // Now get the buffer location we will log the previous value into and store it
4051 Node *log_addr = __ AddP(no_base, buffer, next_index);
4052 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
4053 // update the index
4054 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
4055
4056 } __ else_(); {
4057
4058 // logging buffer is full, call the runtime
4059 const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
4060 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
4061 } __ end_if(); // (!index)
4062 } __ end_if(); // (pre_val != NULL)
4063 } __ end_if(); // (!marking)
4064
4065 // Final sync IdealKit and GraphKit.
4066 final_sync(ideal);
4067 }
4068
4069 /*
4070 * G1 similar to any GC with a Young Generation requires a way to keep track of
4071 * references from Old Generation to Young Generation to make sure all live
4072 * objects are found. G1 also requires to keep track of object references
4073 * between different regions to enable evacuation of old regions, which is done
4074 * as part of mixed collections. References are tracked in remembered sets and
4075 * is continuously updated as reference are written to with the help of the
4076 * post-barrier.
4077 *
4078 * To reduce the number of updates to the remembered set the post-barrier
4079 * filters updates to fields in objects located in the Young Generation,
4080 * the same region as the reference, when the NULL is being written or
4081 * if the card is already marked as dirty by an earlier write.
4082 *
4083 * Under certain circumstances it is possible to avoid generating the
4084 * post-barrier completely if it is possible during compile time to prove
4085 * the object is newly allocated and that no safepoint exists between the
4086 * allocation and the store.
4087 *
4088 * In the case of slow allocation the allocation code must handle the barrier
4089 * as part of the allocation in the case the allocated object is not located
4090 * in the nursery, this would happen for humongous objects. This is similar to
4091 * how CMS is required to handle this case, see the comments for the method
4092 * CollectedHeap::new_store_pre_barrier and OptoRuntime::new_store_pre_barrier.
4093 * A deferred card mark is required for these objects and handled in the above
4094 * mentioned methods.
4095 *
4096 * Returns true if the post barrier can be removed
4097 */
4098 bool GraphKit::g1_can_remove_post_barrier(PhaseTransform* phase, Node* store,
4099 Node* adr) {
4100 intptr_t offset = 0;
4101 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
4102 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
4103
4104 if (offset == Type::OffsetBot) {
4105 return false; // cannot unalias unless there are precise offsets
4106 }
4107
4108 if (alloc == NULL) {
4109 return false; // No allocation found
4110 }
4111
4112 // Start search from Store node
4113 Node* mem = store->in(MemNode::Control);
4114 if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
4115
4116 InitializeNode* st_init = mem->in(0)->as_Initialize();
4117 AllocateNode* st_alloc = st_init->allocation();
4118
4119 // Make sure we are looking at the same allocation
4120 if (alloc == st_alloc) {
4121 return true;
4122 }
4123 }
4124
4125 return false;
4126 }
4127
4128 //
4129 // Update the card table and add card address to the queue
4130 //
4131 void GraphKit::g1_mark_card(IdealKit& ideal,
4132 Node* card_adr,
4133 Node* oop_store,
4134 uint oop_alias_idx,
4135 Node* index,
4136 Node* index_adr,
4137 Node* buffer,
4138 const TypeFunc* tf) {
4139
4140 Node* zero = __ ConI(0);
4141 Node* zeroX = __ ConX(0);
4142 Node* no_base = __ top();
4143 BasicType card_bt = T_BYTE;
4144 // Smash zero into card. MUST BE ORDERED WRT TO STORE
4145 __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw);
4146
4147 // Now do the queue work
4148 __ if_then(index, BoolTest::ne, zeroX); {
4149
4150 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4151 Node* log_addr = __ AddP(no_base, buffer, next_index);
4152
4153 // Order, see storeCM.
4154 __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);
4155 __ store(__ ctrl(), index_adr, next_index, TypeX_X->basic_type(), Compile::AliasIdxRaw, MemNode::unordered);
4156
4157 } __ else_(); {
4158 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), "g1_wb_post", card_adr, __ thread());
4159 } __ end_if();
4160
4161 }
4162
4163 void GraphKit::g1_write_barrier_post(Node* oop_store,
4164 Node* obj,
4165 Node* adr,
4166 uint alias_idx,
4167 Node* val,
4168 BasicType bt,
4169 bool use_precise) {
4170 // If we are writing a NULL then we need no post barrier
4171
4172 if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
4173 // Must be NULL
4174 const Type* t = val->bottom_type();
4175 assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
4176 // No post barrier if writing NULLx
4177 return;
4178 }
4179
4180 if (use_ReduceInitialCardMarks() && obj == just_allocated_object(control())) {
4181 // We can skip marks on a freshly-allocated object in Eden.
4182 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
4183 // That routine informs GC to take appropriate compensating steps,
4184 // upon a slow-path allocation, so as to make this card-mark
4185 // elision safe.
4186 return;
4187 }
4188
4189 if (use_ReduceInitialCardMarks()
4190 && g1_can_remove_post_barrier(&_gvn, oop_store, adr)) {
4191 return;
4192 }
4193
4194 if (!use_precise) {
4195 // All card marks for a (non-array) instance are in one place:
4196 adr = obj;
4197 }
4198 // (Else it's an array (or unknown), and we want more precise card marks.)
4199 assert(adr != NULL, "");
4200
4201 IdealKit ideal(this, true);
4202
4203 Node* tls = __ thread(); // ThreadLocalStorage
4204
4205 Node* no_base = __ top();
4206 float likely = PROB_LIKELY(0.999);
4207 float unlikely = PROB_UNLIKELY(0.999);
4208 Node* young_card = __ ConI((jint)G1SATBCardTableModRefBS::g1_young_card_val());
4209 Node* dirty_card = __ ConI((jint)CardTableModRefBS::dirty_card_val());
4210 Node* zeroX = __ ConX(0);
4211
4212 // Get the alias_index for raw card-mark memory
4213 const TypePtr* card_type = TypeRawPtr::BOTTOM;
4214
4215 const TypeFunc *tf = OptoRuntime::g1_wb_post_Type();
4216
4217 // Offsets into the thread
4218 const int index_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4219 PtrQueue::byte_offset_of_index());
4220 const int buffer_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4221 PtrQueue::byte_offset_of_buf());
4222
4223 // Pointers into the thread
4224
4225 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4226 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4227
4228 // Now some values
4229 // Use ctrl to avoid hoisting these values past a safepoint, which could
4230 // potentially reset these fields in the JavaThread.
4231 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, TypeX_X->basic_type(), Compile::AliasIdxRaw);
4232 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4233
4234 // Convert the store obj pointer to an int prior to doing math on it
4235 // Must use ctrl to prevent "integerized oop" existing across safepoint
4236 Node* cast = __ CastPX(__ ctrl(), adr);
4237
4238 // Divide pointer by card size
4239 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
4240
4241 // Combine card table base and card offset
4242 Node* card_adr = __ AddP(no_base, byte_map_base_node(), card_offset );
4243
4244 // If we know the value being stored does it cross regions?
4245
4246 if (val != NULL) {
4247 // Does the store cause us to cross regions?
4248
4249 // Should be able to do an unsigned compare of region_size instead of
4250 // and extra shift. Do we have an unsigned compare??
4251 // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes);
4252 Node* xor_res = __ URShiftX ( __ XorX( cast, __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes));
4253
4254 // if (xor_res == 0) same region so skip
4255 __ if_then(xor_res, BoolTest::ne, zeroX); {
4256
4257 // No barrier if we are storing a NULL
4258 __ if_then(val, BoolTest::ne, null(), unlikely); {
4259
4260 // Ok must mark the card if not already dirty
4261
4262 // load the original value of the card
4263 Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4264
4265 __ if_then(card_val, BoolTest::ne, young_card); {
4266 sync_kit(ideal);
4267 // Use Op_MemBarVolatile to achieve the effect of a StoreLoad barrier.
4268 insert_mem_bar(Op_MemBarVolatile, oop_store);
4269 __ sync_kit(this);
4270
4271 Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4272 __ if_then(card_val_reload, BoolTest::ne, dirty_card); {
4273 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4274 } __ end_if();
4275 } __ end_if();
4276 } __ end_if();
4277 } __ end_if();
4278 } else {
4279 // Object.clone() instrinsic uses this path.
4280 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4281 }
4282
4283 // Final sync IdealKit and GraphKit.
4284 final_sync(ideal);
4285 }
4286 #undef __
4287
4288
4289 Node* GraphKit::load_String_length(Node* ctrl, Node* str) {
4290 Node* len = load_array_length(load_String_value(ctrl, str));
4291 Node* coder = load_String_coder(ctrl, str);
4292 // Divide length by 2 if coder is UTF16
4293 return _gvn.transform(new RShiftINode(len, coder));
4294 }
4295
4296 Node* GraphKit::load_String_value(Node* ctrl, Node* str) {
4297 int value_offset = java_lang_String::value_offset_in_bytes();
4298 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4299 false, NULL, 0);
4300 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4301 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
4302 TypeAry::make(TypeInt::BYTE, TypeInt::POS),
4303 ciTypeArrayKlass::make(T_BYTE), true, 0);
4304 int value_field_idx = C->get_alias_index(value_field_type);
4305 Node* load = make_load(ctrl, basic_plus_adr(str, str, value_offset),
4306 value_type, T_OBJECT, value_field_idx, MemNode::unordered);
4307 // String.value field is known to be @Stable.
4308 if (UseImplicitStableValues) {
4309 load = cast_array_to_stable(load, value_type);
4310 }
4311 return load;
4312 }
4313
4314 Node* GraphKit::load_String_coder(Node* ctrl, Node* str) {
4315 if (java_lang_String::has_coder_field()) {
4316 if (!CompactStrings) {
4317 return intcon(java_lang_String::CODER_UTF16);
4318 }
4319 int coder_offset = java_lang_String::coder_offset_in_bytes();
4320 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4321 false, NULL, 0);
4322 const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
4323 int coder_field_idx = C->get_alias_index(coder_field_type);
4324 return make_load(ctrl, basic_plus_adr(str, str, coder_offset),
4325 TypeInt::BYTE, T_BYTE, coder_field_idx, MemNode::unordered);
4326 } else {
4327 return intcon(0); // false
4328 }
4329 }
4330
4331 void GraphKit::store_String_value(Node* ctrl, Node* str, Node* value) {
4332 int value_offset = java_lang_String::value_offset_in_bytes();
4333 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4334 false, NULL, 0);
4335 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4336 store_oop_to_object(ctrl, str, basic_plus_adr(str, value_offset), value_field_type,
4337 value, TypeAryPtr::BYTES, T_OBJECT, MemNode::unordered);
4338 }
4339
4340 void GraphKit::store_String_coder(Node* ctrl, Node* str, Node* value) {
4341 int coder_offset = java_lang_String::coder_offset_in_bytes();
4342 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4343 false, NULL, 0);
4344 const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
4345 int coder_field_idx = C->get_alias_index(coder_field_type);
4346 store_to_memory(ctrl, basic_plus_adr(str, coder_offset),
4347 value, T_BYTE, coder_field_idx, MemNode::unordered);
4348 }
4349
4350 Node* GraphKit::compress_string(Node* src, Node* dst, Node* count) {
4351 assert(Matcher::match_rule_supported(Op_StrCompressedCopy), "Intrinsic not supported");
4352 uint idx = C->get_alias_index(TypeAryPtr::BYTES);
4353 StrCompressedCopyNode* str = new StrCompressedCopyNode(control(), memory(idx), src, dst, count);
4354 Node* res_mem = _gvn.transform(new SCMemProjNode(str));
4355 set_memory(res_mem, idx);
4356 return str;
4357 }
4358
4359 void GraphKit::inflate_string(Node* src, Node* dst, Node* count) {
4360 assert(Matcher::match_rule_supported(Op_StrInflatedCopy), "Intrinsic not supported");
4361 uint idx = C->get_alias_index(TypeAryPtr::BYTES);
4362 StrInflatedCopyNode* str = new StrInflatedCopyNode(control(), memory(idx), src, dst, count);
4363 set_memory(_gvn.transform(str), idx);
4364 }
4365
4366 void GraphKit::inflate_string_slow(Node* src, Node* dst, Node* start, Node* count) {
4367 /**
4368 * int i_char = start;
4369 * for (int i_byte = 0; i_byte < count; i_byte++) {
4370 * dst[i_char++] = (char)(src[i_byte] & 0xff);
4371 * }
4372 */
4373 add_predicate();
4374 RegionNode* head = new RegionNode(3);
4375 head->init_req(1, control());
4376 gvn().set_type(head, Type::CONTROL);
4377 record_for_igvn(head);
4378
4379 Node* i_byte = new PhiNode(head, TypeInt::INT);
4380 i_byte->init_req(1, intcon(0));
4381 gvn().set_type(i_byte, TypeInt::INT);
4382 record_for_igvn(i_byte);
4383
4384 Node* i_char = new PhiNode(head, TypeInt::INT);
4385 i_char->init_req(1, start);
4386 gvn().set_type(i_char, TypeInt::INT);
4387 record_for_igvn(i_char);
4388
4389 Node* mem = PhiNode::make(head, memory(TypeAryPtr::BYTES), Type::MEMORY, TypeAryPtr::BYTES);
4390 gvn().set_type(mem, Type::MEMORY);
4391 record_for_igvn(mem);
4392 set_control(head);
4393 set_memory(mem, TypeAryPtr::BYTES);
4394 Node* ch = load_array_element(control(), src, i_byte, TypeAryPtr::BYTES);
4395 Node* st = store_to_memory(control(), array_element_address(dst, i_char, T_BYTE),
4396 AndI(ch, intcon(0xff)), T_CHAR, TypeAryPtr::BYTES, MemNode::unordered);
4397
4398 IfNode* iff = create_and_map_if(head, Bool(CmpI(i_byte, count), BoolTest::lt), PROB_FAIR, COUNT_UNKNOWN);
4399 head->init_req(2, IfTrue(iff));
4400 mem->init_req(2, st);
4401 i_byte->init_req(2, AddI(i_byte, intcon(1)));
4402 i_char->init_req(2, AddI(i_char, intcon(2)));
4403
4404 set_control(IfFalse(iff));
4405 set_memory(st, TypeAryPtr::BYTES);
4406 }
4407
4408 Node* GraphKit::cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type) {
4409 // Reify the property as a CastPP node in Ideal graph to comply with monotonicity
4410 // assumption of CCP analysis.
4411 return _gvn.transform(new CastPPNode(ary, ary_type->cast_to_stable(true)));
4412 }