1 /*
2 * Copyright (c) 2001, 2017, 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 "gc/shenandoah/brooksPointer.hpp"
33 #include "gc/shenandoah/shenandoahConnectionMatrix.hpp"
34 #include "gc/shenandoah/shenandoahHeap.hpp"
35 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "opto/addnode.hpp"
38 #include "opto/castnode.hpp"
39 #include "opto/convertnode.hpp"
40 #include "opto/graphKit.hpp"
41 #include "opto/idealKit.hpp"
42 #include "opto/intrinsicnode.hpp"
43 #include "opto/locknode.hpp"
44 #include "opto/machnode.hpp"
45 #include "opto/opaquenode.hpp"
46 #include "opto/parse.hpp"
47 #include "opto/rootnode.hpp"
48 #include "opto/runtime.hpp"
49 #include "opto/shenandoahSupport.hpp"
50 #include "runtime/deoptimization.hpp"
51 #include "runtime/sharedRuntime.hpp"
52
53 //----------------------------GraphKit-----------------------------------------
54 // Main utility constructor.
55 GraphKit::GraphKit(JVMState* jvms)
56 : Phase(Phase::Parser),
57 _env(C->env()),
58 _gvn(*C->initial_gvn())
59 {
60 _exceptions = jvms->map()->next_exception();
61 if (_exceptions != NULL) jvms->map()->set_next_exception(NULL);
62 set_jvms(jvms);
63 }
64
65 // Private constructor for parser.
66 GraphKit::GraphKit()
67 : Phase(Phase::Parser),
68 _env(C->env()),
69 _gvn(*C->initial_gvn())
70 {
71 _exceptions = NULL;
72 set_map(NULL);
73 debug_only(_sp = -99);
74 debug_only(set_bci(-99));
75 }
76
77
78
79 //---------------------------clean_stack---------------------------------------
80 // Clear away rubbish from the stack area of the JVM state.
81 // This destroys any arguments that may be waiting on the stack.
82 void GraphKit::clean_stack(int from_sp) {
83 SafePointNode* map = this->map();
84 JVMState* jvms = this->jvms();
85 int stk_size = jvms->stk_size();
86 int stkoff = jvms->stkoff();
87 Node* top = this->top();
88 for (int i = from_sp; i < stk_size; i++) {
89 if (map->in(stkoff + i) != top) {
90 map->set_req(stkoff + i, top);
91 }
92 }
93 }
94
95
96 //--------------------------------sync_jvms-----------------------------------
97 // Make sure our current jvms agrees with our parse state.
98 JVMState* GraphKit::sync_jvms() const {
99 JVMState* jvms = this->jvms();
100 jvms->set_bci(bci()); // Record the new bci in the JVMState
101 jvms->set_sp(sp()); // Record the new sp in the JVMState
102 assert(jvms_in_sync(), "jvms is now in sync");
103 return jvms;
104 }
105
106 //--------------------------------sync_jvms_for_reexecute---------------------
107 // Make sure our current jvms agrees with our parse state. This version
108 // uses the reexecute_sp for reexecuting bytecodes.
109 JVMState* GraphKit::sync_jvms_for_reexecute() {
110 JVMState* jvms = this->jvms();
111 jvms->set_bci(bci()); // Record the new bci in the JVMState
112 jvms->set_sp(reexecute_sp()); // Record the new sp in the JVMState
113 return jvms;
114 }
115
116 #ifdef ASSERT
117 bool GraphKit::jvms_in_sync() const {
118 Parse* parse = is_Parse();
119 if (parse == NULL) {
120 if (bci() != jvms()->bci()) return false;
121 if (sp() != (int)jvms()->sp()) return false;
122 return true;
123 }
124 if (jvms()->method() != parse->method()) return false;
125 if (jvms()->bci() != parse->bci()) return false;
126 int jvms_sp = jvms()->sp();
127 if (jvms_sp != parse->sp()) return false;
128 int jvms_depth = jvms()->depth();
129 if (jvms_depth != parse->depth()) return false;
130 return true;
131 }
132
133 // Local helper checks for special internal merge points
134 // used to accumulate and merge exception states.
135 // They are marked by the region's in(0) edge being the map itself.
136 // Such merge points must never "escape" into the parser at large,
137 // until they have been handed to gvn.transform.
138 static bool is_hidden_merge(Node* reg) {
139 if (reg == NULL) return false;
140 if (reg->is_Phi()) {
141 reg = reg->in(0);
142 if (reg == NULL) return false;
143 }
144 return reg->is_Region() && reg->in(0) != NULL && reg->in(0)->is_Root();
145 }
146
147 void GraphKit::verify_map() const {
148 if (map() == NULL) return; // null map is OK
149 assert(map()->req() <= jvms()->endoff(), "no extra garbage on map");
150 assert(!map()->has_exceptions(), "call add_exception_states_from 1st");
151 assert(!is_hidden_merge(control()), "call use_exception_state, not set_map");
152 }
153
154 void GraphKit::verify_exception_state(SafePointNode* ex_map) {
155 assert(ex_map->next_exception() == NULL, "not already part of a chain");
156 assert(has_saved_ex_oop(ex_map), "every exception state has an ex_oop");
157 }
158 #endif
159
160 //---------------------------stop_and_kill_map---------------------------------
161 // Set _map to NULL, signalling a stop to further bytecode execution.
162 // First smash the current map's control to a constant, to mark it dead.
163 void GraphKit::stop_and_kill_map() {
164 SafePointNode* dead_map = stop();
165 if (dead_map != NULL) {
166 dead_map->disconnect_inputs(NULL, C); // Mark the map as killed.
167 assert(dead_map->is_killed(), "must be so marked");
168 }
169 }
170
171
172 //--------------------------------stopped--------------------------------------
173 // Tell if _map is NULL, or control is top.
174 bool GraphKit::stopped() {
175 if (map() == NULL) return true;
176 else if (control() == top()) return true;
177 else return false;
178 }
179
180
181 //-----------------------------has_ex_handler----------------------------------
182 // Tell if this method or any caller method has exception handlers.
183 bool GraphKit::has_ex_handler() {
184 for (JVMState* jvmsp = jvms(); jvmsp != NULL; jvmsp = jvmsp->caller()) {
185 if (jvmsp->has_method() && jvmsp->method()->has_exception_handlers()) {
186 return true;
187 }
188 }
189 return false;
190 }
191
192 //------------------------------save_ex_oop------------------------------------
193 // Save an exception without blowing stack contents or other JVM state.
194 void GraphKit::set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop) {
195 assert(!has_saved_ex_oop(ex_map), "clear ex-oop before setting again");
196 ex_map->add_req(ex_oop);
197 debug_only(verify_exception_state(ex_map));
198 }
199
200 inline static Node* common_saved_ex_oop(SafePointNode* ex_map, bool clear_it) {
201 assert(GraphKit::has_saved_ex_oop(ex_map), "ex_oop must be there");
202 Node* ex_oop = ex_map->in(ex_map->req()-1);
203 if (clear_it) ex_map->del_req(ex_map->req()-1);
204 return ex_oop;
205 }
206
207 //-----------------------------saved_ex_oop------------------------------------
208 // Recover a saved exception from its map.
209 Node* GraphKit::saved_ex_oop(SafePointNode* ex_map) {
210 return common_saved_ex_oop(ex_map, false);
211 }
212
213 //--------------------------clear_saved_ex_oop---------------------------------
214 // Erase a previously saved exception from its map.
215 Node* GraphKit::clear_saved_ex_oop(SafePointNode* ex_map) {
216 return common_saved_ex_oop(ex_map, true);
217 }
218
219 #ifdef ASSERT
220 //---------------------------has_saved_ex_oop----------------------------------
221 // Erase a previously saved exception from its map.
222 bool GraphKit::has_saved_ex_oop(SafePointNode* ex_map) {
223 return ex_map->req() == ex_map->jvms()->endoff()+1;
224 }
225 #endif
226
227 //-------------------------make_exception_state--------------------------------
228 // Turn the current JVM state into an exception state, appending the ex_oop.
229 SafePointNode* GraphKit::make_exception_state(Node* ex_oop) {
230 sync_jvms();
231 SafePointNode* ex_map = stop(); // do not manipulate this map any more
232 set_saved_ex_oop(ex_map, ex_oop);
233 return ex_map;
234 }
235
236
237 //--------------------------add_exception_state--------------------------------
238 // Add an exception to my list of exceptions.
239 void GraphKit::add_exception_state(SafePointNode* ex_map) {
240 if (ex_map == NULL || ex_map->control() == top()) {
241 return;
242 }
243 #ifdef ASSERT
244 verify_exception_state(ex_map);
245 if (has_exceptions()) {
246 assert(ex_map->jvms()->same_calls_as(_exceptions->jvms()), "all collected exceptions must come from the same place");
247 }
248 #endif
249
250 // If there is already an exception of exactly this type, merge with it.
251 // In particular, null-checks and other low-level exceptions common up here.
252 Node* ex_oop = saved_ex_oop(ex_map);
253 const Type* ex_type = _gvn.type(ex_oop);
254 if (ex_oop == top()) {
255 // No action needed.
256 return;
257 }
258 assert(ex_type->isa_instptr(), "exception must be an instance");
259 for (SafePointNode* e2 = _exceptions; e2 != NULL; e2 = e2->next_exception()) {
260 const Type* ex_type2 = _gvn.type(saved_ex_oop(e2));
261 // We check sp also because call bytecodes can generate exceptions
262 // both before and after arguments are popped!
263 if (ex_type2 == ex_type
264 && e2->_jvms->sp() == ex_map->_jvms->sp()) {
265 combine_exception_states(ex_map, e2);
266 return;
267 }
268 }
269
270 // No pre-existing exception of the same type. Chain it on the list.
271 push_exception_state(ex_map);
272 }
273
274 //-----------------------add_exception_states_from-----------------------------
275 void GraphKit::add_exception_states_from(JVMState* jvms) {
276 SafePointNode* ex_map = jvms->map()->next_exception();
277 if (ex_map != NULL) {
278 jvms->map()->set_next_exception(NULL);
279 for (SafePointNode* next_map; ex_map != NULL; ex_map = next_map) {
280 next_map = ex_map->next_exception();
281 ex_map->set_next_exception(NULL);
282 add_exception_state(ex_map);
283 }
284 }
285 }
286
287 //-----------------------transfer_exceptions_into_jvms-------------------------
288 JVMState* GraphKit::transfer_exceptions_into_jvms() {
289 if (map() == NULL) {
290 // We need a JVMS to carry the exceptions, but the map has gone away.
291 // Create a scratch JVMS, cloned from any of the exception states...
292 if (has_exceptions()) {
293 _map = _exceptions;
294 _map = clone_map();
295 _map->set_next_exception(NULL);
296 clear_saved_ex_oop(_map);
297 debug_only(verify_map());
298 } else {
299 // ...or created from scratch
300 JVMState* jvms = new (C) JVMState(_method, NULL);
301 jvms->set_bci(_bci);
302 jvms->set_sp(_sp);
303 jvms->set_map(new SafePointNode(TypeFunc::Parms, jvms));
304 set_jvms(jvms);
305 for (uint i = 0; i < map()->req(); i++) map()->init_req(i, top());
306 set_all_memory(top());
307 while (map()->req() < jvms->endoff()) map()->add_req(top());
308 }
309 // (This is a kludge, in case you didn't notice.)
310 set_control(top());
311 }
312 JVMState* jvms = sync_jvms();
313 assert(!jvms->map()->has_exceptions(), "no exceptions on this map yet");
314 jvms->map()->set_next_exception(_exceptions);
315 _exceptions = NULL; // done with this set of exceptions
316 return jvms;
317 }
318
319 static inline void add_n_reqs(Node* dstphi, Node* srcphi) {
320 assert(is_hidden_merge(dstphi), "must be a special merge node");
321 assert(is_hidden_merge(srcphi), "must be a special merge node");
322 uint limit = srcphi->req();
323 for (uint i = PhiNode::Input; i < limit; i++) {
324 dstphi->add_req(srcphi->in(i));
325 }
326 }
327 static inline void add_one_req(Node* dstphi, Node* src) {
328 assert(is_hidden_merge(dstphi), "must be a special merge node");
329 assert(!is_hidden_merge(src), "must not be a special merge node");
330 dstphi->add_req(src);
331 }
332
333 //-----------------------combine_exception_states------------------------------
334 // This helper function combines exception states by building phis on a
335 // specially marked state-merging region. These regions and phis are
336 // untransformed, and can build up gradually. The region is marked by
337 // having a control input of its exception map, rather than NULL. Such
338 // regions do not appear except in this function, and in use_exception_state.
339 void GraphKit::combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map) {
340 if (failing()) return; // dying anyway...
341 JVMState* ex_jvms = ex_map->_jvms;
342 assert(ex_jvms->same_calls_as(phi_map->_jvms), "consistent call chains");
343 assert(ex_jvms->stkoff() == phi_map->_jvms->stkoff(), "matching locals");
344 assert(ex_jvms->sp() == phi_map->_jvms->sp(), "matching stack sizes");
345 assert(ex_jvms->monoff() == phi_map->_jvms->monoff(), "matching JVMS");
346 assert(ex_jvms->scloff() == phi_map->_jvms->scloff(), "matching scalar replaced objects");
347 assert(ex_map->req() == phi_map->req(), "matching maps");
348 uint tos = ex_jvms->stkoff() + ex_jvms->sp();
349 Node* hidden_merge_mark = root();
350 Node* region = phi_map->control();
351 MergeMemNode* phi_mem = phi_map->merged_memory();
352 MergeMemNode* ex_mem = ex_map->merged_memory();
353 if (region->in(0) != hidden_merge_mark) {
354 // The control input is not (yet) a specially-marked region in phi_map.
355 // Make it so, and build some phis.
356 region = new RegionNode(2);
357 _gvn.set_type(region, Type::CONTROL);
358 region->set_req(0, hidden_merge_mark); // marks an internal ex-state
359 region->init_req(1, phi_map->control());
360 phi_map->set_control(region);
361 Node* io_phi = PhiNode::make(region, phi_map->i_o(), Type::ABIO);
362 record_for_igvn(io_phi);
363 _gvn.set_type(io_phi, Type::ABIO);
364 phi_map->set_i_o(io_phi);
365 for (MergeMemStream mms(phi_mem); mms.next_non_empty(); ) {
366 Node* m = mms.memory();
367 Node* m_phi = PhiNode::make(region, m, Type::MEMORY, mms.adr_type(C));
368 record_for_igvn(m_phi);
369 _gvn.set_type(m_phi, Type::MEMORY);
370 mms.set_memory(m_phi);
371 }
372 }
373
374 // Either or both of phi_map and ex_map might already be converted into phis.
375 Node* ex_control = ex_map->control();
376 // if there is special marking on ex_map also, we add multiple edges from src
377 bool add_multiple = (ex_control->in(0) == hidden_merge_mark);
378 // how wide was the destination phi_map, originally?
379 uint orig_width = region->req();
380
381 if (add_multiple) {
382 add_n_reqs(region, ex_control);
383 add_n_reqs(phi_map->i_o(), ex_map->i_o());
384 } else {
385 // ex_map has no merges, so we just add single edges everywhere
386 add_one_req(region, ex_control);
387 add_one_req(phi_map->i_o(), ex_map->i_o());
388 }
389 for (MergeMemStream mms(phi_mem, ex_mem); mms.next_non_empty2(); ) {
390 if (mms.is_empty()) {
391 // get a copy of the base memory, and patch some inputs into it
392 const TypePtr* adr_type = mms.adr_type(C);
393 Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
394 assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
395 mms.set_memory(phi);
396 // Prepare to append interesting stuff onto the newly sliced phi:
397 while (phi->req() > orig_width) phi->del_req(phi->req()-1);
398 }
399 // Append stuff from ex_map:
400 if (add_multiple) {
401 add_n_reqs(mms.memory(), mms.memory2());
402 } else {
403 add_one_req(mms.memory(), mms.memory2());
404 }
405 }
406 uint limit = ex_map->req();
407 for (uint i = TypeFunc::Parms; i < limit; i++) {
408 // Skip everything in the JVMS after tos. (The ex_oop follows.)
409 if (i == tos) i = ex_jvms->monoff();
410 Node* src = ex_map->in(i);
411 Node* dst = phi_map->in(i);
412 if (src != dst) {
413 PhiNode* phi;
414 if (dst->in(0) != region) {
415 dst = phi = PhiNode::make(region, dst, _gvn.type(dst));
416 record_for_igvn(phi);
417 _gvn.set_type(phi, phi->type());
418 phi_map->set_req(i, dst);
419 // Prepare to append interesting stuff onto the new phi:
420 while (dst->req() > orig_width) dst->del_req(dst->req()-1);
421 } else {
422 assert(dst->is_Phi(), "nobody else uses a hidden region");
423 phi = dst->as_Phi();
424 }
425 if (add_multiple && src->in(0) == ex_control) {
426 // Both are phis.
427 add_n_reqs(dst, src);
428 } else {
429 while (dst->req() < region->req()) add_one_req(dst, src);
430 }
431 const Type* srctype = _gvn.type(src);
432 if (phi->type() != srctype) {
433 const Type* dsttype = phi->type()->meet_speculative(srctype);
434 if (phi->type() != dsttype) {
435 phi->set_type(dsttype);
436 _gvn.set_type(phi, dsttype);
437 }
438 }
439 }
440 }
441 phi_map->merge_replaced_nodes_with(ex_map);
442 }
443
444 //--------------------------use_exception_state--------------------------------
445 Node* GraphKit::use_exception_state(SafePointNode* phi_map) {
446 if (failing()) { stop(); return top(); }
447 Node* region = phi_map->control();
448 Node* hidden_merge_mark = root();
449 assert(phi_map->jvms()->map() == phi_map, "sanity: 1-1 relation");
450 Node* ex_oop = clear_saved_ex_oop(phi_map);
451 if (region->in(0) == hidden_merge_mark) {
452 // Special marking for internal ex-states. Process the phis now.
453 region->set_req(0, region); // now it's an ordinary region
454 set_jvms(phi_map->jvms()); // ...so now we can use it as a map
455 // Note: Setting the jvms also sets the bci and sp.
456 set_control(_gvn.transform(region));
457 uint tos = jvms()->stkoff() + sp();
458 for (uint i = 1; i < tos; i++) {
459 Node* x = phi_map->in(i);
460 if (x->in(0) == region) {
461 assert(x->is_Phi(), "expected a special phi");
462 phi_map->set_req(i, _gvn.transform(x));
463 }
464 }
465 for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
466 Node* x = mms.memory();
467 if (x->in(0) == region) {
468 assert(x->is_Phi(), "nobody else uses a hidden region");
469 mms.set_memory(_gvn.transform(x));
470 }
471 }
472 if (ex_oop->in(0) == region) {
473 assert(ex_oop->is_Phi(), "expected a special phi");
474 ex_oop = _gvn.transform(ex_oop);
475 }
476 } else {
477 set_jvms(phi_map->jvms());
478 }
479
480 assert(!is_hidden_merge(phi_map->control()), "hidden ex. states cleared");
481 assert(!is_hidden_merge(phi_map->i_o()), "hidden ex. states cleared");
482 return ex_oop;
483 }
484
485 //---------------------------------java_bc-------------------------------------
486 Bytecodes::Code GraphKit::java_bc() const {
487 ciMethod* method = this->method();
488 int bci = this->bci();
489 if (method != NULL && bci != InvocationEntryBci)
490 return method->java_code_at_bci(bci);
491 else
492 return Bytecodes::_illegal;
493 }
494
495 void GraphKit::uncommon_trap_if_should_post_on_exceptions(Deoptimization::DeoptReason reason,
496 bool must_throw) {
497 // if the exception capability is set, then we will generate code
498 // to check the JavaThread.should_post_on_exceptions flag to see
499 // if we actually need to report exception events (for this
500 // thread). If we don't need to report exception events, we will
501 // take the normal fast path provided by add_exception_events. If
502 // exception event reporting is enabled for this thread, we will
503 // take the uncommon_trap in the BuildCutout below.
504
505 // first must access the should_post_on_exceptions_flag in this thread's JavaThread
506 Node* jthread = _gvn.transform(new ThreadLocalNode());
507 Node* adr = basic_plus_adr(top(), jthread, in_bytes(JavaThread::should_post_on_exceptions_flag_offset()));
508 Node* should_post_flag = make_load(control(), adr, TypeInt::INT, T_INT, Compile::AliasIdxRaw, MemNode::unordered);
509
510 // Test the should_post_on_exceptions_flag vs. 0
511 Node* chk = _gvn.transform( new CmpINode(should_post_flag, intcon(0)) );
512 Node* tst = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
513
514 // Branch to slow_path if should_post_on_exceptions_flag was true
515 { BuildCutout unless(this, tst, PROB_MAX);
516 // Do not try anything fancy if we're notifying the VM on every throw.
517 // Cf. case Bytecodes::_athrow in parse2.cpp.
518 uncommon_trap(reason, Deoptimization::Action_none,
519 (ciKlass*)NULL, (char*)NULL, must_throw);
520 }
521
522 }
523
524 //------------------------------builtin_throw----------------------------------
525 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {
526 bool must_throw = true;
527
528 if (env()->jvmti_can_post_on_exceptions()) {
529 // check if we must post exception events, take uncommon trap if so
530 uncommon_trap_if_should_post_on_exceptions(reason, must_throw);
531 // here if should_post_on_exceptions is false
532 // continue on with the normal codegen
533 }
534
535 // If this particular condition has not yet happened at this
536 // bytecode, then use the uncommon trap mechanism, and allow for
537 // a future recompilation if several traps occur here.
538 // If the throw is hot, try to use a more complicated inline mechanism
539 // which keeps execution inside the compiled code.
540 bool treat_throw_as_hot = false;
541 ciMethodData* md = method()->method_data();
542
543 if (ProfileTraps) {
544 if (too_many_traps(reason)) {
545 treat_throw_as_hot = true;
546 }
547 // (If there is no MDO at all, assume it is early in
548 // execution, and that any deopts are part of the
549 // startup transient, and don't need to be remembered.)
550
551 // Also, if there is a local exception handler, treat all throws
552 // as hot if there has been at least one in this method.
553 if (C->trap_count(reason) != 0
554 && method()->method_data()->trap_count(reason) != 0
555 && has_ex_handler()) {
556 treat_throw_as_hot = true;
557 }
558 }
559
560 // If this throw happens frequently, an uncommon trap might cause
561 // a performance pothole. If there is a local exception handler,
562 // and if this particular bytecode appears to be deoptimizing often,
563 // let us handle the throw inline, with a preconstructed instance.
564 // Note: If the deopt count has blown up, the uncommon trap
565 // runtime is going to flush this nmethod, not matter what.
566 if (treat_throw_as_hot
567 && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {
568 // If the throw is local, we use a pre-existing instance and
569 // punt on the backtrace. This would lead to a missing backtrace
570 // (a repeat of 4292742) if the backtrace object is ever asked
571 // for its backtrace.
572 // Fixing this remaining case of 4292742 requires some flavor of
573 // escape analysis. Leave that for the future.
574 ciInstance* ex_obj = NULL;
575 switch (reason) {
576 case Deoptimization::Reason_null_check:
577 ex_obj = env()->NullPointerException_instance();
578 break;
579 case Deoptimization::Reason_div0_check:
580 ex_obj = env()->ArithmeticException_instance();
581 break;
582 case Deoptimization::Reason_range_check:
583 ex_obj = env()->ArrayIndexOutOfBoundsException_instance();
584 break;
585 case Deoptimization::Reason_class_check:
586 if (java_bc() == Bytecodes::_aastore) {
587 ex_obj = env()->ArrayStoreException_instance();
588 } else {
589 ex_obj = env()->ClassCastException_instance();
590 }
591 break;
592 default:
593 break;
594 }
595 if (failing()) { stop(); return; } // exception allocation might fail
596 if (ex_obj != NULL) {
597 // Cheat with a preallocated exception object.
598 if (C->log() != NULL)
599 C->log()->elem("hot_throw preallocated='1' reason='%s'",
600 Deoptimization::trap_reason_name(reason));
601 const TypeInstPtr* ex_con = TypeInstPtr::make(ex_obj);
602 Node* ex_node = _gvn.transform(ConNode::make(ex_con));
603
604 ex_node = shenandoah_write_barrier(ex_node);
605
606 // Clear the detail message of the preallocated exception object.
607 // Weblogic sometimes mutates the detail message of exceptions
608 // using reflection.
609 int offset = java_lang_Throwable::get_detailMessage_offset();
610 const TypePtr* adr_typ = ex_con->add_offset(offset);
611
612 Node *adr = basic_plus_adr(ex_node, ex_node, offset);
613 const TypeOopPtr* val_type = TypeOopPtr::make_from_klass(env()->String_klass());
614 // Conservatively release stores of object references.
615 Node *store = store_oop_to_object(control(), ex_node, adr, adr_typ, null(), val_type, T_OBJECT, MemNode::release);
616
617 add_exception_state(make_exception_state(ex_node));
618 return;
619 }
620 }
621
622 // %%% Maybe add entry to OptoRuntime which directly throws the exc.?
623 // It won't be much cheaper than bailing to the interp., since we'll
624 // have to pass up all the debug-info, and the runtime will have to
625 // create the stack trace.
626
627 // Usual case: Bail to interpreter.
628 // Reserve the right to recompile if we haven't seen anything yet.
629
630 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? C->method() : NULL;
631 Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;
632 if (treat_throw_as_hot
633 && (method()->method_data()->trap_recompiled_at(bci(), m)
634 || C->too_many_traps(reason))) {
635 // We cannot afford to take more traps here. Suffer in the interpreter.
636 if (C->log() != NULL)
637 C->log()->elem("hot_throw preallocated='0' reason='%s' mcount='%d'",
638 Deoptimization::trap_reason_name(reason),
639 C->trap_count(reason));
640 action = Deoptimization::Action_none;
641 }
642
643 // "must_throw" prunes the JVM state to include only the stack, if there
644 // are no local exception handlers. This should cut down on register
645 // allocation time and code size, by drastically reducing the number
646 // of in-edges on the call to the uncommon trap.
647
648 uncommon_trap(reason, action, (ciKlass*)NULL, (char*)NULL, must_throw);
649 }
650
651
652 //----------------------------PreserveJVMState---------------------------------
653 PreserveJVMState::PreserveJVMState(GraphKit* kit, bool clone_map) {
654 debug_only(kit->verify_map());
655 _kit = kit;
656 _map = kit->map(); // preserve the map
657 _sp = kit->sp();
658 kit->set_map(clone_map ? kit->clone_map() : NULL);
659 #ifdef ASSERT
660 _bci = kit->bci();
661 Parse* parser = kit->is_Parse();
662 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
663 _block = block;
664 #endif
665 }
666 PreserveJVMState::~PreserveJVMState() {
667 GraphKit* kit = _kit;
668 #ifdef ASSERT
669 assert(kit->bci() == _bci, "bci must not shift");
670 Parse* parser = kit->is_Parse();
671 int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->rpo();
672 assert(block == _block, "block must not shift");
673 #endif
674 kit->set_map(_map);
675 kit->set_sp(_sp);
676 }
677
678
679 //-----------------------------BuildCutout-------------------------------------
680 BuildCutout::BuildCutout(GraphKit* kit, Node* p, float prob, float cnt)
681 : PreserveJVMState(kit)
682 {
683 assert(p->is_Con() || p->is_Bool(), "test must be a bool");
684 SafePointNode* outer_map = _map; // preserved map is caller's
685 SafePointNode* inner_map = kit->map();
686 IfNode* iff = kit->create_and_map_if(outer_map->control(), p, prob, cnt);
687 outer_map->set_control(kit->gvn().transform( new IfTrueNode(iff) ));
688 inner_map->set_control(kit->gvn().transform( new IfFalseNode(iff) ));
689 }
690 BuildCutout::~BuildCutout() {
691 GraphKit* kit = _kit;
692 assert(kit->stopped(), "cutout code must stop, throw, return, etc.");
693 }
694
695 //---------------------------PreserveReexecuteState----------------------------
696 PreserveReexecuteState::PreserveReexecuteState(GraphKit* kit) {
697 assert(!kit->stopped(), "must call stopped() before");
698 _kit = kit;
699 _sp = kit->sp();
700 _reexecute = kit->jvms()->_reexecute;
701 }
702 PreserveReexecuteState::~PreserveReexecuteState() {
703 if (_kit->stopped()) return;
704 _kit->jvms()->_reexecute = _reexecute;
705 _kit->set_sp(_sp);
706 }
707
708 //------------------------------clone_map--------------------------------------
709 // Implementation of PreserveJVMState
710 //
711 // Only clone_map(...) here. If this function is only used in the
712 // PreserveJVMState class we may want to get rid of this extra
713 // function eventually and do it all there.
714
715 SafePointNode* GraphKit::clone_map() {
716 if (map() == NULL) return NULL;
717
718 // Clone the memory edge first
719 Node* mem = MergeMemNode::make(map()->memory());
720 gvn().set_type_bottom(mem);
721
722 SafePointNode *clonemap = (SafePointNode*)map()->clone();
723 JVMState* jvms = this->jvms();
724 JVMState* clonejvms = jvms->clone_shallow(C);
725 clonemap->set_memory(mem);
726 clonemap->set_jvms(clonejvms);
727 clonejvms->set_map(clonemap);
728 record_for_igvn(clonemap);
729 gvn().set_type_bottom(clonemap);
730 return clonemap;
731 }
732
733
734 //-----------------------------set_map_clone-----------------------------------
735 void GraphKit::set_map_clone(SafePointNode* m) {
736 _map = m;
737 _map = clone_map();
738 _map->set_next_exception(NULL);
739 debug_only(verify_map());
740 }
741
742
743 //----------------------------kill_dead_locals---------------------------------
744 // Detect any locals which are known to be dead, and force them to top.
745 void GraphKit::kill_dead_locals() {
746 // Consult the liveness information for the locals. If any
747 // of them are unused, then they can be replaced by top(). This
748 // should help register allocation time and cut down on the size
749 // of the deoptimization information.
750
751 // This call is made from many of the bytecode handling
752 // subroutines called from the Big Switch in do_one_bytecode.
753 // Every bytecode which might include a slow path is responsible
754 // for killing its dead locals. The more consistent we
755 // are about killing deads, the fewer useless phis will be
756 // constructed for them at various merge points.
757
758 // bci can be -1 (InvocationEntryBci). We return the entry
759 // liveness for the method.
760
761 if (method() == NULL || method()->code_size() == 0) {
762 // We are building a graph for a call to a native method.
763 // All locals are live.
764 return;
765 }
766
767 ResourceMark rm;
768
769 // Consult the liveness information for the locals. If any
770 // of them are unused, then they can be replaced by top(). This
771 // should help register allocation time and cut down on the size
772 // of the deoptimization information.
773 MethodLivenessResult live_locals = method()->liveness_at_bci(bci());
774
775 int len = (int)live_locals.size();
776 assert(len <= jvms()->loc_size(), "too many live locals");
777 for (int local = 0; local < len; local++) {
778 if (!live_locals.at(local)) {
779 set_local(local, top());
780 }
781 }
782 }
783
784 #ifdef ASSERT
785 //-------------------------dead_locals_are_killed------------------------------
786 // Return true if all dead locals are set to top in the map.
787 // Used to assert "clean" debug info at various points.
788 bool GraphKit::dead_locals_are_killed() {
789 if (method() == NULL || method()->code_size() == 0) {
790 // No locals need to be dead, so all is as it should be.
791 return true;
792 }
793
794 // Make sure somebody called kill_dead_locals upstream.
795 ResourceMark rm;
796 for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {
797 if (jvms->loc_size() == 0) continue; // no locals to consult
798 SafePointNode* map = jvms->map();
799 ciMethod* method = jvms->method();
800 int bci = jvms->bci();
801 if (jvms == this->jvms()) {
802 bci = this->bci(); // it might not yet be synched
803 }
804 MethodLivenessResult live_locals = method->liveness_at_bci(bci);
805 int len = (int)live_locals.size();
806 if (!live_locals.is_valid() || len == 0)
807 // This method is trivial, or is poisoned by a breakpoint.
808 return true;
809 assert(len == jvms->loc_size(), "live map consistent with locals map");
810 for (int local = 0; local < len; local++) {
811 if (!live_locals.at(local) && map->local(jvms, local) != top()) {
812 if (PrintMiscellaneous && (Verbose || WizardMode)) {
813 tty->print_cr("Zombie local %d: ", local);
814 jvms->dump();
815 }
816 return false;
817 }
818 }
819 }
820 return true;
821 }
822
823 #endif //ASSERT
824
825 // Helper function for enforcing certain bytecodes to reexecute if
826 // deoptimization happens
827 static bool should_reexecute_implied_by_bytecode(JVMState *jvms, bool is_anewarray) {
828 ciMethod* cur_method = jvms->method();
829 int cur_bci = jvms->bci();
830 if (cur_method != NULL && cur_bci != InvocationEntryBci) {
831 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
832 return Interpreter::bytecode_should_reexecute(code) ||
833 (is_anewarray && code == Bytecodes::_multianewarray);
834 // Reexecute _multianewarray bytecode which was replaced with
835 // sequence of [a]newarray. See Parse::do_multianewarray().
836 //
837 // Note: interpreter should not have it set since this optimization
838 // is limited by dimensions and guarded by flag so in some cases
839 // multianewarray() runtime calls will be generated and
840 // the bytecode should not be reexecutes (stack will not be reset).
841 } else
842 return false;
843 }
844
845 // Helper function for adding JVMState and debug information to node
846 void GraphKit::add_safepoint_edges(SafePointNode* call, bool must_throw) {
847 // Add the safepoint edges to the call (or other safepoint).
848
849 // Make sure dead locals are set to top. This
850 // should help register allocation time and cut down on the size
851 // of the deoptimization information.
852 assert(dead_locals_are_killed(), "garbage in debug info before safepoint");
853
854 // Walk the inline list to fill in the correct set of JVMState's
855 // Also fill in the associated edges for each JVMState.
856
857 // If the bytecode needs to be reexecuted we need to put
858 // the arguments back on the stack.
859 const bool should_reexecute = jvms()->should_reexecute();
860 JVMState* youngest_jvms = should_reexecute ? sync_jvms_for_reexecute() : sync_jvms();
861
862 // NOTE: set_bci (called from sync_jvms) might reset the reexecute bit to
863 // undefined if the bci is different. This is normal for Parse but it
864 // should not happen for LibraryCallKit because only one bci is processed.
865 assert(!is_LibraryCallKit() || (jvms()->should_reexecute() == should_reexecute),
866 "in LibraryCallKit the reexecute bit should not change");
867
868 // If we are guaranteed to throw, we can prune everything but the
869 // input to the current bytecode.
870 bool can_prune_locals = false;
871 uint stack_slots_not_pruned = 0;
872 int inputs = 0, depth = 0;
873 if (must_throw) {
874 assert(method() == youngest_jvms->method(), "sanity");
875 if (compute_stack_effects(inputs, depth)) {
876 can_prune_locals = true;
877 stack_slots_not_pruned = inputs;
878 }
879 }
880
881 if (env()->should_retain_local_variables()) {
882 // At any safepoint, this method can get breakpointed, which would
883 // then require an immediate deoptimization.
884 can_prune_locals = false; // do not prune locals
885 stack_slots_not_pruned = 0;
886 }
887
888 // do not scribble on the input jvms
889 JVMState* out_jvms = youngest_jvms->clone_deep(C);
890 call->set_jvms(out_jvms); // Start jvms list for call node
891
892 // For a known set of bytecodes, the interpreter should reexecute them if
893 // deoptimization happens. We set the reexecute state for them here
894 if (out_jvms->is_reexecute_undefined() && //don't change if already specified
895 should_reexecute_implied_by_bytecode(out_jvms, call->is_AllocateArray())) {
896 out_jvms->set_should_reexecute(true); //NOTE: youngest_jvms not changed
897 }
898
899 // Presize the call:
900 DEBUG_ONLY(uint non_debug_edges = call->req());
901 call->add_req_batch(top(), youngest_jvms->debug_depth());
902 assert(call->req() == non_debug_edges + youngest_jvms->debug_depth(), "");
903
904 // Set up edges so that the call looks like this:
905 // Call [state:] ctl io mem fptr retadr
906 // [parms:] parm0 ... parmN
907 // [root:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
908 // [...mid:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN [...]
909 // [young:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN
910 // Note that caller debug info precedes callee debug info.
911
912 // Fill pointer walks backwards from "young:" to "root:" in the diagram above:
913 uint debug_ptr = call->req();
914
915 // Loop over the map input edges associated with jvms, add them
916 // to the call node, & reset all offsets to match call node array.
917 for (JVMState* in_jvms = youngest_jvms; in_jvms != NULL; ) {
918 uint debug_end = debug_ptr;
919 uint debug_start = debug_ptr - in_jvms->debug_size();
920 debug_ptr = debug_start; // back up the ptr
921
922 uint p = debug_start; // walks forward in [debug_start, debug_end)
923 uint j, k, l;
924 SafePointNode* in_map = in_jvms->map();
925 out_jvms->set_map(call);
926
927 if (can_prune_locals) {
928 assert(in_jvms->method() == out_jvms->method(), "sanity");
929 // If the current throw can reach an exception handler in this JVMS,
930 // then we must keep everything live that can reach that handler.
931 // As a quick and dirty approximation, we look for any handlers at all.
932 if (in_jvms->method()->has_exception_handlers()) {
933 can_prune_locals = false;
934 }
935 }
936
937 // Add the Locals
938 k = in_jvms->locoff();
939 l = in_jvms->loc_size();
940 out_jvms->set_locoff(p);
941 if (!can_prune_locals) {
942 for (j = 0; j < l; j++)
943 call->set_req(p++, in_map->in(k+j));
944 } else {
945 p += l; // already set to top above by add_req_batch
946 }
947
948 // Add the Expression Stack
949 k = in_jvms->stkoff();
950 l = in_jvms->sp();
951 out_jvms->set_stkoff(p);
952 if (!can_prune_locals) {
953 for (j = 0; j < l; j++)
954 call->set_req(p++, in_map->in(k+j));
955 } else if (can_prune_locals && stack_slots_not_pruned != 0) {
956 // Divide stack into {S0,...,S1}, where S0 is set to top.
957 uint s1 = stack_slots_not_pruned;
958 stack_slots_not_pruned = 0; // for next iteration
959 if (s1 > l) s1 = l;
960 uint s0 = l - s1;
961 p += s0; // skip the tops preinstalled by add_req_batch
962 for (j = s0; j < l; j++)
963 call->set_req(p++, in_map->in(k+j));
964 } else {
965 p += l; // already set to top above by add_req_batch
966 }
967
968 // Add the Monitors
969 k = in_jvms->monoff();
970 l = in_jvms->mon_size();
971 out_jvms->set_monoff(p);
972 for (j = 0; j < l; j++)
973 call->set_req(p++, in_map->in(k+j));
974
975 // Copy any scalar object fields.
976 k = in_jvms->scloff();
977 l = in_jvms->scl_size();
978 out_jvms->set_scloff(p);
979 for (j = 0; j < l; j++)
980 call->set_req(p++, in_map->in(k+j));
981
982 // Finish the new jvms.
983 out_jvms->set_endoff(p);
984
985 assert(out_jvms->endoff() == debug_end, "fill ptr must match");
986 assert(out_jvms->depth() == in_jvms->depth(), "depth must match");
987 assert(out_jvms->loc_size() == in_jvms->loc_size(), "size must match");
988 assert(out_jvms->mon_size() == in_jvms->mon_size(), "size must match");
989 assert(out_jvms->scl_size() == in_jvms->scl_size(), "size must match");
990 assert(out_jvms->debug_size() == in_jvms->debug_size(), "size must match");
991
992 // Update the two tail pointers in parallel.
993 out_jvms = out_jvms->caller();
994 in_jvms = in_jvms->caller();
995 }
996
997 assert(debug_ptr == non_debug_edges, "debug info must fit exactly");
998
999 // Test the correctness of JVMState::debug_xxx accessors:
1000 assert(call->jvms()->debug_start() == non_debug_edges, "");
1001 assert(call->jvms()->debug_end() == call->req(), "");
1002 assert(call->jvms()->debug_depth() == call->req() - non_debug_edges, "");
1003 }
1004
1005 bool GraphKit::compute_stack_effects(int& inputs, int& depth) {
1006 Bytecodes::Code code = java_bc();
1007 if (code == Bytecodes::_wide) {
1008 code = method()->java_code_at_bci(bci() + 1);
1009 }
1010
1011 BasicType rtype = T_ILLEGAL;
1012 int rsize = 0;
1013
1014 if (code != Bytecodes::_illegal) {
1015 depth = Bytecodes::depth(code); // checkcast=0, athrow=-1
1016 rtype = Bytecodes::result_type(code); // checkcast=P, athrow=V
1017 if (rtype < T_CONFLICT)
1018 rsize = type2size[rtype];
1019 }
1020
1021 switch (code) {
1022 case Bytecodes::_illegal:
1023 return false;
1024
1025 case Bytecodes::_ldc:
1026 case Bytecodes::_ldc_w:
1027 case Bytecodes::_ldc2_w:
1028 inputs = 0;
1029 break;
1030
1031 case Bytecodes::_dup: inputs = 1; break;
1032 case Bytecodes::_dup_x1: inputs = 2; break;
1033 case Bytecodes::_dup_x2: inputs = 3; break;
1034 case Bytecodes::_dup2: inputs = 2; break;
1035 case Bytecodes::_dup2_x1: inputs = 3; break;
1036 case Bytecodes::_dup2_x2: inputs = 4; break;
1037 case Bytecodes::_swap: inputs = 2; break;
1038 case Bytecodes::_arraylength: inputs = 1; break;
1039
1040 case Bytecodes::_getstatic:
1041 case Bytecodes::_putstatic:
1042 case Bytecodes::_getfield:
1043 case Bytecodes::_putfield:
1044 {
1045 bool ignored_will_link;
1046 ciField* field = method()->get_field_at_bci(bci(), ignored_will_link);
1047 int size = field->type()->size();
1048 bool is_get = (depth >= 0), is_static = (depth & 1);
1049 inputs = (is_static ? 0 : 1);
1050 if (is_get) {
1051 depth = size - inputs;
1052 } else {
1053 inputs += size; // putxxx pops the value from the stack
1054 depth = - inputs;
1055 }
1056 }
1057 break;
1058
1059 case Bytecodes::_invokevirtual:
1060 case Bytecodes::_invokespecial:
1061 case Bytecodes::_invokestatic:
1062 case Bytecodes::_invokedynamic:
1063 case Bytecodes::_invokeinterface:
1064 {
1065 bool ignored_will_link;
1066 ciSignature* declared_signature = NULL;
1067 ciMethod* ignored_callee = method()->get_method_at_bci(bci(), ignored_will_link, &declared_signature);
1068 assert(declared_signature != NULL, "cannot be null");
1069 inputs = declared_signature->arg_size_for_bc(code);
1070 int size = declared_signature->return_type()->size();
1071 depth = size - inputs;
1072 }
1073 break;
1074
1075 case Bytecodes::_multianewarray:
1076 {
1077 ciBytecodeStream iter(method());
1078 iter.reset_to_bci(bci());
1079 iter.next();
1080 inputs = iter.get_dimensions();
1081 assert(rsize == 1, "");
1082 depth = rsize - inputs;
1083 }
1084 break;
1085
1086 case Bytecodes::_ireturn:
1087 case Bytecodes::_lreturn:
1088 case Bytecodes::_freturn:
1089 case Bytecodes::_dreturn:
1090 case Bytecodes::_areturn:
1091 assert(rsize == -depth, "");
1092 inputs = rsize;
1093 break;
1094
1095 case Bytecodes::_jsr:
1096 case Bytecodes::_jsr_w:
1097 inputs = 0;
1098 depth = 1; // S.B. depth=1, not zero
1099 break;
1100
1101 default:
1102 // bytecode produces a typed result
1103 inputs = rsize - depth;
1104 assert(inputs >= 0, "");
1105 break;
1106 }
1107
1108 #ifdef ASSERT
1109 // spot check
1110 int outputs = depth + inputs;
1111 assert(outputs >= 0, "sanity");
1112 switch (code) {
1113 case Bytecodes::_checkcast: assert(inputs == 1 && outputs == 1, ""); break;
1114 case Bytecodes::_athrow: assert(inputs == 1 && outputs == 0, ""); break;
1115 case Bytecodes::_aload_0: assert(inputs == 0 && outputs == 1, ""); break;
1116 case Bytecodes::_return: assert(inputs == 0 && outputs == 0, ""); break;
1117 case Bytecodes::_drem: assert(inputs == 4 && outputs == 2, ""); break;
1118 default: break;
1119 }
1120 #endif //ASSERT
1121
1122 return true;
1123 }
1124
1125
1126
1127 //------------------------------basic_plus_adr---------------------------------
1128 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {
1129 // short-circuit a common case
1130 if (offset == intcon(0)) return ptr;
1131 return _gvn.transform( new AddPNode(base, ptr, offset) );
1132 }
1133
1134 Node* GraphKit::ConvI2L(Node* offset) {
1135 // short-circuit a common case
1136 jint offset_con = find_int_con(offset, Type::OffsetBot);
1137 if (offset_con != Type::OffsetBot) {
1138 return longcon((jlong) offset_con);
1139 }
1140 return _gvn.transform( new ConvI2LNode(offset));
1141 }
1142
1143 Node* GraphKit::ConvI2UL(Node* offset) {
1144 juint offset_con = (juint) find_int_con(offset, Type::OffsetBot);
1145 if (offset_con != (juint) Type::OffsetBot) {
1146 return longcon((julong) offset_con);
1147 }
1148 Node* conv = _gvn.transform( new ConvI2LNode(offset));
1149 Node* mask = _gvn.transform(ConLNode::make((julong) max_juint));
1150 return _gvn.transform( new AndLNode(conv, mask) );
1151 }
1152
1153 Node* GraphKit::ConvL2I(Node* offset) {
1154 // short-circuit a common case
1155 jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);
1156 if (offset_con != (jlong)Type::OffsetBot) {
1157 return intcon((int) offset_con);
1158 }
1159 return _gvn.transform( new ConvL2INode(offset));
1160 }
1161
1162 //-------------------------load_object_klass-----------------------------------
1163 Node* GraphKit::load_object_klass(Node* obj) {
1164 // Special-case a fresh allocation to avoid building nodes:
1165 Node* akls = AllocateNode::Ideal_klass(obj, &_gvn);
1166 if (akls != NULL) return akls;
1167 Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());
1168 return _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), k_adr, TypeInstPtr::KLASS));
1169 }
1170
1171 //-------------------------load_array_length-----------------------------------
1172 Node* GraphKit::load_array_length(Node* array) {
1173 // Special-case a fresh allocation to avoid building nodes:
1174 AllocateArrayNode* alloc = AllocateArrayNode::Ideal_array_allocation(array, &_gvn);
1175 Node *alen;
1176 if (alloc == NULL) {
1177 Node *r_adr = basic_plus_adr(array, arrayOopDesc::length_offset_in_bytes());
1178 alen = _gvn.transform( new LoadRangeNode(0, immutable_memory(), r_adr, TypeInt::POS));
1179 } else {
1180 alen = alloc->Ideal_length();
1181 Node* ccast = alloc->make_ideal_length(_gvn.type(array)->is_oopptr(), &_gvn);
1182 if (ccast != alen) {
1183 alen = _gvn.transform(ccast);
1184 }
1185 }
1186 return alen;
1187 }
1188
1189 //------------------------------do_null_check----------------------------------
1190 // Helper function to do a NULL pointer check. Returned value is
1191 // the incoming address with NULL casted away. You are allowed to use the
1192 // not-null value only if you are control dependent on the test.
1193 #ifndef PRODUCT
1194 extern int explicit_null_checks_inserted,
1195 explicit_null_checks_elided;
1196 #endif
1197 Node* GraphKit::null_check_common(Node* value, BasicType type,
1198 // optional arguments for variations:
1199 bool assert_null,
1200 Node* *null_control,
1201 bool speculative) {
1202 assert(!assert_null || null_control == NULL, "not both at once");
1203 if (stopped()) return top();
1204 NOT_PRODUCT(explicit_null_checks_inserted++);
1205
1206 // Construct NULL check
1207 Node *chk = NULL;
1208 switch(type) {
1209 case T_LONG : chk = new CmpLNode(value, _gvn.zerocon(T_LONG)); break;
1210 case T_INT : chk = new CmpINode(value, _gvn.intcon(0)); break;
1211 case T_ARRAY : // fall through
1212 type = T_OBJECT; // simplify further tests
1213 case T_OBJECT : {
1214 const Type *t = _gvn.type( value );
1215
1216 const TypeOopPtr* tp = t->isa_oopptr();
1217 if (tp != NULL && tp->klass() != NULL && !tp->klass()->is_loaded()
1218 // Only for do_null_check, not any of its siblings:
1219 && !assert_null && null_control == NULL) {
1220 // Usually, any field access or invocation on an unloaded oop type
1221 // will simply fail to link, since the statically linked class is
1222 // likely also to be unloaded. However, in -Xcomp mode, sometimes
1223 // the static class is loaded but the sharper oop type is not.
1224 // Rather than checking for this obscure case in lots of places,
1225 // we simply observe that a null check on an unloaded class
1226 // will always be followed by a nonsense operation, so we
1227 // can just issue the uncommon trap here.
1228 // Our access to the unloaded class will only be correct
1229 // after it has been loaded and initialized, which requires
1230 // a trip through the interpreter.
1231 #ifndef PRODUCT
1232 if (WizardMode) { tty->print("Null check of unloaded "); tp->klass()->print(); tty->cr(); }
1233 #endif
1234 uncommon_trap(Deoptimization::Reason_unloaded,
1235 Deoptimization::Action_reinterpret,
1236 tp->klass(), "!loaded");
1237 return top();
1238 }
1239
1240 if (assert_null) {
1241 // See if the type is contained in NULL_PTR.
1242 // If so, then the value is already null.
1243 if (t->higher_equal(TypePtr::NULL_PTR)) {
1244 NOT_PRODUCT(explicit_null_checks_elided++);
1245 return value; // Elided null assert quickly!
1246 }
1247 } else {
1248 // See if mixing in the NULL pointer changes type.
1249 // If so, then the NULL pointer was not allowed in the original
1250 // type. In other words, "value" was not-null.
1251 if (t->meet(TypePtr::NULL_PTR) != t->remove_speculative()) {
1252 // same as: if (!TypePtr::NULL_PTR->higher_equal(t)) ...
1253 NOT_PRODUCT(explicit_null_checks_elided++);
1254 return value; // Elided null check quickly!
1255 }
1256 }
1257 chk = new CmpPNode( value, null() );
1258 break;
1259 }
1260
1261 default:
1262 fatal("unexpected type: %s", type2name(type));
1263 }
1264 assert(chk != NULL, "sanity check");
1265 chk = _gvn.transform(chk);
1266
1267 BoolTest::mask btest = assert_null ? BoolTest::eq : BoolTest::ne;
1268 BoolNode *btst = new BoolNode( chk, btest);
1269 Node *tst = _gvn.transform( btst );
1270
1271 //-----------
1272 // if peephole optimizations occurred, a prior test existed.
1273 // If a prior test existed, maybe it dominates as we can avoid this test.
1274 if (tst != btst && type == T_OBJECT) {
1275 // At this point we want to scan up the CFG to see if we can
1276 // find an identical test (and so avoid this test altogether).
1277 Node *cfg = control();
1278 int depth = 0;
1279 while( depth < 16 ) { // Limit search depth for speed
1280 if( cfg->Opcode() == Op_IfTrue &&
1281 cfg->in(0)->in(1) == tst ) {
1282 // Found prior test. Use "cast_not_null" to construct an identical
1283 // CastPP (and hence hash to) as already exists for the prior test.
1284 // Return that casted value.
1285 if (assert_null) {
1286 replace_in_map(value, null());
1287 return null(); // do not issue the redundant test
1288 }
1289 Node *oldcontrol = control();
1290 set_control(cfg);
1291 Node *res = cast_not_null(value);
1292 set_control(oldcontrol);
1293 NOT_PRODUCT(explicit_null_checks_elided++);
1294 return res;
1295 }
1296 cfg = IfNode::up_one_dom(cfg, /*linear_only=*/ true);
1297 if (cfg == NULL) break; // Quit at region nodes
1298 depth++;
1299 }
1300 }
1301
1302 //-----------
1303 // Branch to failure if null
1304 float ok_prob = PROB_MAX; // a priori estimate: nulls never happen
1305 Deoptimization::DeoptReason reason;
1306 if (assert_null) {
1307 reason = Deoptimization::reason_null_assert(speculative);
1308 } else if (type == T_OBJECT) {
1309 reason = Deoptimization::reason_null_check(speculative);
1310 } else {
1311 reason = Deoptimization::Reason_div0_check;
1312 }
1313 // %%% Since Reason_unhandled is not recorded on a per-bytecode basis,
1314 // ciMethodData::has_trap_at will return a conservative -1 if any
1315 // must-be-null assertion has failed. This could cause performance
1316 // problems for a method after its first do_null_assert failure.
1317 // Consider using 'Reason_class_check' instead?
1318
1319 // To cause an implicit null check, we set the not-null probability
1320 // to the maximum (PROB_MAX). For an explicit check the probability
1321 // is set to a smaller value.
1322 if (null_control != NULL || too_many_traps(reason)) {
1323 // probability is less likely
1324 ok_prob = PROB_LIKELY_MAG(3);
1325 } else if (!assert_null &&
1326 (ImplicitNullCheckThreshold > 0) &&
1327 method() != NULL &&
1328 (method()->method_data()->trap_count(reason)
1329 >= (uint)ImplicitNullCheckThreshold)) {
1330 ok_prob = PROB_LIKELY_MAG(3);
1331 }
1332
1333 if (null_control != NULL) {
1334 IfNode* iff = create_and_map_if(control(), tst, ok_prob, COUNT_UNKNOWN);
1335 Node* null_true = _gvn.transform( new IfFalseNode(iff));
1336 set_control( _gvn.transform( new IfTrueNode(iff)));
1337 #ifndef PRODUCT
1338 if (null_true == top()) {
1339 explicit_null_checks_elided++;
1340 }
1341 #endif
1342 (*null_control) = null_true;
1343 } else {
1344 BuildCutout unless(this, tst, ok_prob);
1345 // Check for optimizer eliding test at parse time
1346 if (stopped()) {
1347 // Failure not possible; do not bother making uncommon trap.
1348 NOT_PRODUCT(explicit_null_checks_elided++);
1349 } else if (assert_null) {
1350 uncommon_trap(reason,
1351 Deoptimization::Action_make_not_entrant,
1352 NULL, "assert_null");
1353 } else {
1354 replace_in_map(value, zerocon(type));
1355 builtin_throw(reason);
1356 }
1357 }
1358
1359 // Must throw exception, fall-thru not possible?
1360 if (stopped()) {
1361 return top(); // No result
1362 }
1363
1364 if (assert_null) {
1365 // Cast obj to null on this path.
1366 replace_in_map(value, zerocon(type));
1367 return zerocon(type);
1368 }
1369
1370 // Cast obj to not-null on this path, if there is no null_control.
1371 // (If there is a null_control, a non-null value may come back to haunt us.)
1372 if (type == T_OBJECT) {
1373 Node* cast = cast_not_null(value, false);
1374 if (null_control == NULL || (*null_control) == top())
1375 replace_in_map(value, cast);
1376 value = cast;
1377 }
1378
1379 return value;
1380 }
1381
1382
1383 //------------------------------cast_not_null----------------------------------
1384 // Cast obj to not-null on this path
1385 Node* GraphKit::cast_not_null(Node* obj, bool do_replace_in_map) {
1386 const Type *t = _gvn.type(obj);
1387 const Type *t_not_null = t->join_speculative(TypePtr::NOTNULL);
1388 // Object is already not-null?
1389 if( t == t_not_null ) return obj;
1390
1391 Node *cast = new CastPPNode(obj,t_not_null);
1392 cast->init_req(0, control());
1393 cast = _gvn.transform( cast );
1394
1395 // Scan for instances of 'obj' in the current JVM mapping.
1396 // These instances are known to be not-null after the test.
1397 if (do_replace_in_map)
1398 replace_in_map(obj, cast);
1399
1400 return cast; // Return casted value
1401 }
1402
1403 // Sometimes in intrinsics, we implicitly know an object is not null
1404 // (there's no actual null check) so we can cast it to not null. In
1405 // the course of optimizations, the input to the cast can become null.
1406 // In that case that data path will die and we need the control path
1407 // to become dead as well to keep the graph consistent. So we have to
1408 // add a check for null for which one branch can't be taken. It uses
1409 // an Opaque4 node that will cause the check to be removed after loop
1410 // opts so the test goes away and the compiled code doesn't execute a
1411 // useless check.
1412 Node* GraphKit::must_be_not_null(Node* value, bool do_replace_in_map) {
1413 Node* chk = _gvn.transform(new CmpPNode(value, null()));
1414 Node *tst = _gvn.transform(new BoolNode(chk, BoolTest::ne));
1415 Node* opaq = _gvn.transform(new Opaque4Node(C, tst, intcon(1)));
1416 IfNode *iff = new IfNode(control(), opaq, PROB_MAX, COUNT_UNKNOWN);
1417 _gvn.set_type(iff, iff->Value(&_gvn));
1418 Node *if_f = _gvn.transform(new IfFalseNode(iff));
1419 Node *frame = _gvn.transform(new ParmNode(C->start(), TypeFunc::FramePtr));
1420 Node *halt = _gvn.transform(new HaltNode(if_f, frame));
1421 C->root()->add_req(halt);
1422 Node *if_t = _gvn.transform(new IfTrueNode(iff));
1423 set_control(if_t);
1424 return cast_not_null(value, do_replace_in_map);
1425 }
1426
1427
1428 //--------------------------replace_in_map-------------------------------------
1429 void GraphKit::replace_in_map(Node* old, Node* neww) {
1430 if (old == neww) {
1431 return;
1432 }
1433
1434 map()->replace_edge(old, neww);
1435
1436 // Note: This operation potentially replaces any edge
1437 // on the map. This includes locals, stack, and monitors
1438 // of the current (innermost) JVM state.
1439
1440 // don't let inconsistent types from profiling escape this
1441 // method
1442
1443 const Type* told = _gvn.type(old);
1444 const Type* tnew = _gvn.type(neww);
1445
1446 if (!tnew->higher_equal(told)) {
1447 return;
1448 }
1449
1450 map()->record_replaced_node(old, neww);
1451 }
1452
1453
1454 //=============================================================================
1455 //--------------------------------memory---------------------------------------
1456 Node* GraphKit::memory(uint alias_idx) {
1457 MergeMemNode* mem = merged_memory();
1458 Node* p = mem->memory_at(alias_idx);
1459 _gvn.set_type(p, Type::MEMORY); // must be mapped
1460 return p;
1461 }
1462
1463 //-----------------------------reset_memory------------------------------------
1464 Node* GraphKit::reset_memory() {
1465 Node* mem = map()->memory();
1466 // do not use this node for any more parsing!
1467 debug_only( map()->set_memory((Node*)NULL) );
1468 return _gvn.transform( mem );
1469 }
1470
1471 //------------------------------set_all_memory---------------------------------
1472 void GraphKit::set_all_memory(Node* newmem) {
1473 Node* mergemem = MergeMemNode::make(newmem);
1474 gvn().set_type_bottom(mergemem);
1475 map()->set_memory(mergemem);
1476 }
1477
1478 //------------------------------set_all_memory_call----------------------------
1479 void GraphKit::set_all_memory_call(Node* call, bool separate_io_proj) {
1480 Node* newmem = _gvn.transform( new ProjNode(call, TypeFunc::Memory, separate_io_proj) );
1481 set_all_memory(newmem);
1482 }
1483
1484 //=============================================================================
1485 //
1486 // parser factory methods for MemNodes
1487 //
1488 // These are layered on top of the factory methods in LoadNode and StoreNode,
1489 // and integrate with the parser's memory state and _gvn engine.
1490 //
1491
1492 // factory methods in "int adr_idx"
1493 Node* GraphKit::make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,
1494 int adr_idx,
1495 MemNode::MemOrd mo,
1496 LoadNode::ControlDependency control_dependency,
1497 bool require_atomic_access,
1498 bool unaligned,
1499 bool mismatched) {
1500 assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );
1501 const TypePtr* adr_type = NULL; // debug-mode-only argument
1502 debug_only(adr_type = C->get_adr_type(adr_idx));
1503 Node* mem = memory(adr_idx);
1504 Node* ld;
1505 if (require_atomic_access && bt == T_LONG) {
1506 ld = LoadLNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency, unaligned, mismatched);
1507 } else if (require_atomic_access && bt == T_DOUBLE) {
1508 ld = LoadDNode::make_atomic(ctl, mem, adr, adr_type, t, mo, control_dependency, unaligned, mismatched);
1509 } else {
1510 ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt, mo, control_dependency, unaligned, mismatched);
1511 }
1512 ld = _gvn.transform(ld);
1513 if (((bt == T_OBJECT) && C->do_escape_analysis()) || C->eliminate_boxing()) {
1514 // Improve graph before escape analysis and boxing elimination.
1515 record_for_igvn(ld);
1516 }
1517 return ld;
1518 }
1519
1520 Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,
1521 int adr_idx,
1522 MemNode::MemOrd mo,
1523 bool require_atomic_access,
1524 bool unaligned,
1525 bool mismatched) {
1526 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1527 const TypePtr* adr_type = NULL;
1528 debug_only(adr_type = C->get_adr_type(adr_idx));
1529 Node *mem = memory(adr_idx);
1530 Node* st;
1531 if (require_atomic_access && bt == T_LONG) {
1532 st = StoreLNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1533 } else if (require_atomic_access && bt == T_DOUBLE) {
1534 st = StoreDNode::make_atomic(ctl, mem, adr, adr_type, val, mo);
1535 } else {
1536 st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt, mo);
1537 }
1538 if (unaligned) {
1539 st->as_Store()->set_unaligned_access();
1540 }
1541 if (mismatched) {
1542 st->as_Store()->set_mismatched_access();
1543 }
1544 st = _gvn.transform(st);
1545 set_memory(st, adr_idx);
1546 // Back-to-back stores can only remove intermediate store with DU info
1547 // so push on worklist for optimizer.
1548 if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))
1549 record_for_igvn(st);
1550
1551 return st;
1552 }
1553
1554
1555 Node* GraphKit::pre_barrier(bool do_load,
1556 Node* ctl,
1557 Node* obj,
1558 Node* adr,
1559 uint adr_idx,
1560 Node* val,
1561 const TypeOopPtr* val_type,
1562 Node* pre_val,
1563 BasicType bt) {
1564
1565 BarrierSet* bs = Universe::heap()->barrier_set();
1566 set_control(ctl);
1567 switch (bs->kind()) {
1568 case BarrierSet::G1SATBCTLogging:
1569 g1_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
1570 return val;
1571 case BarrierSet::ShenandoahBarrierSet:
1572 return shenandoah_write_barrier_pre(do_load, obj, adr, adr_idx, val, val_type, pre_val, bt);
1573
1574 case BarrierSet::CardTableForRS:
1575 case BarrierSet::CardTableExtension:
1576 case BarrierSet::ModRef:
1577 break;
1578
1579 default :
1580 ShouldNotReachHere();
1581
1582 }
1583 return val;
1584 }
1585
1586 bool GraphKit::can_move_pre_barrier() const {
1587 BarrierSet* bs = Universe::heap()->barrier_set();
1588 switch (bs->kind()) {
1589 case BarrierSet::G1SATBCTLogging:
1590 case BarrierSet::ShenandoahBarrierSet:
1591 return true; // Can move it if no safepoint
1592
1593 case BarrierSet::CardTableForRS:
1594 case BarrierSet::CardTableExtension:
1595 case BarrierSet::ModRef:
1596 return true; // There is no pre-barrier
1597
1598 default :
1599 ShouldNotReachHere();
1600 }
1601 return false;
1602 }
1603
1604 void GraphKit::post_barrier(Node* ctl,
1605 Node* store,
1606 Node* obj,
1607 Node* adr,
1608 uint adr_idx,
1609 Node* val,
1610 BasicType bt,
1611 bool use_precise) {
1612 BarrierSet* bs = Universe::heap()->barrier_set();
1613 set_control(ctl);
1614 switch (bs->kind()) {
1615 case BarrierSet::G1SATBCTLogging:
1616 g1_write_barrier_post(store, obj, adr, adr_idx, val, bt, use_precise);
1617 break;
1618
1619 case BarrierSet::CardTableForRS:
1620 case BarrierSet::CardTableExtension:
1621 write_barrier_post(store, obj, adr, adr_idx, val, use_precise);
1622 break;
1623
1624 case BarrierSet::ModRef:
1625 case BarrierSet::ShenandoahBarrierSet:
1626 break;
1627
1628 default :
1629 ShouldNotReachHere();
1630
1631 }
1632 }
1633
1634 Node* GraphKit::store_oop(Node* ctl,
1635 Node* obj,
1636 Node* adr,
1637 const TypePtr* adr_type,
1638 Node* val,
1639 const TypeOopPtr* val_type,
1640 BasicType bt,
1641 bool use_precise,
1642 MemNode::MemOrd mo,
1643 bool mismatched) {
1644 // Transformation of a value which could be NULL pointer (CastPP #NULL)
1645 // could be delayed during Parse (for example, in adjust_map_after_if()).
1646 // Execute transformation here to avoid barrier generation in such case.
1647 if (_gvn.type(val) == TypePtr::NULL_PTR)
1648 val = _gvn.makecon(TypePtr::NULL_PTR);
1649
1650 set_control(ctl);
1651 if (stopped()) return top(); // Dead path ?
1652
1653 assert(bt == T_OBJECT, "sanity");
1654 assert(val != NULL, "not dead path");
1655 uint adr_idx = C->get_alias_index(adr_type);
1656 assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );
1657
1658 val = pre_barrier(true /* do_load */,
1659 control(), obj, adr, adr_idx, val, val_type,
1660 NULL /* pre_val */,
1661 bt);
1662
1663 Node* store = store_to_memory(control(), adr, val, bt, adr_idx, mo, mismatched);
1664 post_barrier(control(), store, obj, adr, adr_idx, val, bt, use_precise);
1665 return store;
1666 }
1667
1668 // Could be an array or object we don't know at compile time (unsafe ref.)
1669 Node* GraphKit::store_oop_to_unknown(Node* ctl,
1670 Node* obj, // containing obj
1671 Node* adr, // actual adress to store val at
1672 const TypePtr* adr_type,
1673 Node* val,
1674 BasicType bt,
1675 MemNode::MemOrd mo,
1676 bool mismatched) {
1677 Compile::AliasType* at = C->alias_type(adr_type);
1678 const TypeOopPtr* val_type = NULL;
1679 if (adr_type->isa_instptr()) {
1680 if (at->field() != NULL) {
1681 // known field. This code is a copy of the do_put_xxx logic.
1682 ciField* field = at->field();
1683 if (!field->type()->is_loaded()) {
1684 val_type = TypeInstPtr::BOTTOM;
1685 } else {
1686 val_type = TypeOopPtr::make_from_klass(field->type()->as_klass());
1687 }
1688 }
1689 } else if (adr_type->isa_aryptr()) {
1690 val_type = adr_type->is_aryptr()->elem()->make_oopptr();
1691 }
1692 if (val_type == NULL) {
1693 val_type = TypeInstPtr::BOTTOM;
1694 }
1695 return store_oop(ctl, obj, adr, adr_type, val, val_type, bt, true, mo, mismatched);
1696 }
1697
1698
1699 //-------------------------array_element_address-------------------------
1700 Node* GraphKit::array_element_address(Node* ary, Node* idx, BasicType elembt,
1701 const TypeInt* sizetype, Node* ctrl) {
1702 uint shift = exact_log2(type2aelembytes(elembt));
1703 uint header = arrayOopDesc::base_offset_in_bytes(elembt);
1704
1705 // short-circuit a common case (saves lots of confusing waste motion)
1706 jint idx_con = find_int_con(idx, -1);
1707 if (idx_con >= 0) {
1708 intptr_t offset = header + ((intptr_t)idx_con << shift);
1709 return basic_plus_adr(ary, offset);
1710 }
1711
1712 // must be correct type for alignment purposes
1713 Node* base = basic_plus_adr(ary, header);
1714 idx = Compile::conv_I2X_index(&_gvn, idx, sizetype, ctrl);
1715 Node* scale = _gvn.transform( new LShiftXNode(idx, intcon(shift)) );
1716 return basic_plus_adr(ary, base, scale);
1717 }
1718
1719 //-------------------------load_array_element-------------------------
1720 Node* GraphKit::load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype) {
1721 const Type* elemtype = arytype->elem();
1722 BasicType elembt = elemtype->array_element_basic_type();
1723 Node* adr = array_element_address(ary, idx, elembt, arytype->size());
1724 if (elembt == T_NARROWOOP) {
1725 elembt = T_OBJECT; // To satisfy switch in LoadNode::make()
1726 }
1727 Node* ld = make_load(ctl, adr, elemtype, elembt, arytype, MemNode::unordered);
1728 return ld;
1729 }
1730
1731 //-------------------------set_arguments_for_java_call-------------------------
1732 // Arguments (pre-popped from the stack) are taken from the JVMS.
1733 void GraphKit::set_arguments_for_java_call(CallJavaNode* call) {
1734 // Add the call arguments:
1735 uint nargs = call->method()->arg_size();
1736 for (uint i = 0; i < nargs; i++) {
1737 Node* arg = argument(i);
1738 call->init_req(i + TypeFunc::Parms, arg);
1739 }
1740 }
1741
1742 //---------------------------set_edges_for_java_call---------------------------
1743 // Connect a newly created call into the current JVMS.
1744 // A return value node (if any) is returned from set_edges_for_java_call.
1745 void GraphKit::set_edges_for_java_call(CallJavaNode* call, bool must_throw, bool separate_io_proj) {
1746
1747 // Add the predefined inputs:
1748 call->init_req( TypeFunc::Control, control() );
1749 call->init_req( TypeFunc::I_O , i_o() );
1750 call->init_req( TypeFunc::Memory , reset_memory() );
1751 call->init_req( TypeFunc::FramePtr, frameptr() );
1752 call->init_req( TypeFunc::ReturnAdr, top() );
1753
1754 add_safepoint_edges(call, must_throw);
1755
1756 Node* xcall = _gvn.transform(call);
1757
1758 if (xcall == top()) {
1759 set_control(top());
1760 return;
1761 }
1762 assert(xcall == call, "call identity is stable");
1763
1764 // Re-use the current map to produce the result.
1765
1766 set_control(_gvn.transform(new ProjNode(call, TypeFunc::Control)));
1767 set_i_o( _gvn.transform(new ProjNode(call, TypeFunc::I_O , separate_io_proj)));
1768 set_all_memory_call(xcall, separate_io_proj);
1769
1770 //return xcall; // no need, caller already has it
1771 }
1772
1773 Node* GraphKit::set_results_for_java_call(CallJavaNode* call, bool separate_io_proj) {
1774 if (stopped()) return top(); // maybe the call folded up?
1775
1776 // Capture the return value, if any.
1777 Node* ret;
1778 if (call->method() == NULL ||
1779 call->method()->return_type()->basic_type() == T_VOID)
1780 ret = top();
1781 else ret = _gvn.transform(new ProjNode(call, TypeFunc::Parms));
1782
1783 // Note: Since any out-of-line call can produce an exception,
1784 // we always insert an I_O projection from the call into the result.
1785
1786 make_slow_call_ex(call, env()->Throwable_klass(), separate_io_proj);
1787
1788 if (separate_io_proj) {
1789 // The caller requested separate projections be used by the fall
1790 // through and exceptional paths, so replace the projections for
1791 // the fall through path.
1792 set_i_o(_gvn.transform( new ProjNode(call, TypeFunc::I_O) ));
1793 set_all_memory(_gvn.transform( new ProjNode(call, TypeFunc::Memory) ));
1794 }
1795 return ret;
1796 }
1797
1798 //--------------------set_predefined_input_for_runtime_call--------------------
1799 // Reading and setting the memory state is way conservative here.
1800 // The real problem is that I am not doing real Type analysis on memory,
1801 // so I cannot distinguish card mark stores from other stores. Across a GC
1802 // point the Store Barrier and the card mark memory has to agree. I cannot
1803 // have a card mark store and its barrier split across the GC point from
1804 // either above or below. Here I get that to happen by reading ALL of memory.
1805 // A better answer would be to separate out card marks from other memory.
1806 // For now, return the input memory state, so that it can be reused
1807 // after the call, if this call has restricted memory effects.
1808 Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call) {
1809 // Set fixed predefined input arguments
1810 Node* memory = reset_memory();
1811 call->init_req( TypeFunc::Control, control() );
1812 call->init_req( TypeFunc::I_O, top() ); // does no i/o
1813 call->init_req( TypeFunc::Memory, memory ); // may gc ptrs
1814 call->init_req( TypeFunc::FramePtr, frameptr() );
1815 call->init_req( TypeFunc::ReturnAdr, top() );
1816 return memory;
1817 }
1818
1819 //-------------------set_predefined_output_for_runtime_call--------------------
1820 // Set control and memory (not i_o) from the call.
1821 // If keep_mem is not NULL, use it for the output state,
1822 // except for the RawPtr output of the call, if hook_mem is TypeRawPtr::BOTTOM.
1823 // If hook_mem is NULL, this call produces no memory effects at all.
1824 // If hook_mem is a Java-visible memory slice (such as arraycopy operands),
1825 // then only that memory slice is taken from the call.
1826 // In the last case, we must put an appropriate memory barrier before
1827 // the call, so as to create the correct anti-dependencies on loads
1828 // preceding the call.
1829 void GraphKit::set_predefined_output_for_runtime_call(Node* call,
1830 Node* keep_mem,
1831 const TypePtr* hook_mem) {
1832 // no i/o
1833 set_control(_gvn.transform( new ProjNode(call,TypeFunc::Control) ));
1834 if (keep_mem) {
1835 // First clone the existing memory state
1836 set_all_memory(keep_mem);
1837 if (hook_mem != NULL) {
1838 // Make memory for the call
1839 Node* mem = _gvn.transform( new ProjNode(call, TypeFunc::Memory) );
1840 // Set the RawPtr memory state only. This covers all the heap top/GC stuff
1841 // We also use hook_mem to extract specific effects from arraycopy stubs.
1842 set_memory(mem, hook_mem);
1843 }
1844 // ...else the call has NO memory effects.
1845
1846 // Make sure the call advertises its memory effects precisely.
1847 // This lets us build accurate anti-dependences in gcm.cpp.
1848 assert(C->alias_type(call->adr_type()) == C->alias_type(hook_mem),
1849 "call node must be constructed correctly");
1850 } else {
1851 assert(hook_mem == NULL, "");
1852 // This is not a "slow path" call; all memory comes from the call.
1853 set_all_memory_call(call);
1854 }
1855 }
1856
1857
1858 // Replace the call with the current state of the kit.
1859 void GraphKit::replace_call(CallNode* call, Node* result, bool do_replaced_nodes) {
1860 JVMState* ejvms = NULL;
1861 if (has_exceptions()) {
1862 ejvms = transfer_exceptions_into_jvms();
1863 }
1864
1865 ReplacedNodes replaced_nodes = map()->replaced_nodes();
1866 ReplacedNodes replaced_nodes_exception;
1867 Node* ex_ctl = top();
1868
1869 SafePointNode* final_state = stop();
1870
1871 // Find all the needed outputs of this call
1872 CallProjections callprojs;
1873 call->extract_projections(&callprojs, true);
1874
1875 Node* init_mem = call->in(TypeFunc::Memory);
1876 Node* final_mem = final_state->in(TypeFunc::Memory);
1877 Node* final_ctl = final_state->in(TypeFunc::Control);
1878 Node* final_io = final_state->in(TypeFunc::I_O);
1879
1880 // Replace all the old call edges with the edges from the inlining result
1881 if (callprojs.fallthrough_catchproj != NULL) {
1882 C->gvn_replace_by(callprojs.fallthrough_catchproj, final_ctl);
1883 }
1884 if (callprojs.fallthrough_memproj != NULL) {
1885 if (final_mem->is_MergeMem()) {
1886 // Parser's exits MergeMem was not transformed but may be optimized
1887 final_mem = _gvn.transform(final_mem);
1888 }
1889 C->gvn_replace_by(callprojs.fallthrough_memproj, final_mem);
1890 }
1891 if (callprojs.fallthrough_ioproj != NULL) {
1892 C->gvn_replace_by(callprojs.fallthrough_ioproj, final_io);
1893 }
1894
1895 // Replace the result with the new result if it exists and is used
1896 if (callprojs.resproj != NULL && result != NULL) {
1897 C->gvn_replace_by(callprojs.resproj, result);
1898 }
1899
1900 if (ejvms == NULL) {
1901 // No exception edges to simply kill off those paths
1902 if (callprojs.catchall_catchproj != NULL) {
1903 C->gvn_replace_by(callprojs.catchall_catchproj, C->top());
1904 }
1905 if (callprojs.catchall_memproj != NULL) {
1906 C->gvn_replace_by(callprojs.catchall_memproj, C->top());
1907 }
1908 if (callprojs.catchall_ioproj != NULL) {
1909 C->gvn_replace_by(callprojs.catchall_ioproj, C->top());
1910 }
1911 // Replace the old exception object with top
1912 if (callprojs.exobj != NULL) {
1913 C->gvn_replace_by(callprojs.exobj, C->top());
1914 }
1915 } else {
1916 GraphKit ekit(ejvms);
1917
1918 // Load my combined exception state into the kit, with all phis transformed:
1919 SafePointNode* ex_map = ekit.combine_and_pop_all_exception_states();
1920 replaced_nodes_exception = ex_map->replaced_nodes();
1921
1922 Node* ex_oop = ekit.use_exception_state(ex_map);
1923
1924 if (callprojs.catchall_catchproj != NULL) {
1925 C->gvn_replace_by(callprojs.catchall_catchproj, ekit.control());
1926 ex_ctl = ekit.control();
1927 }
1928 if (callprojs.catchall_memproj != NULL) {
1929 C->gvn_replace_by(callprojs.catchall_memproj, ekit.reset_memory());
1930 }
1931 if (callprojs.catchall_ioproj != NULL) {
1932 C->gvn_replace_by(callprojs.catchall_ioproj, ekit.i_o());
1933 }
1934
1935 // Replace the old exception object with the newly created one
1936 if (callprojs.exobj != NULL) {
1937 C->gvn_replace_by(callprojs.exobj, ex_oop);
1938 }
1939 }
1940
1941 // Disconnect the call from the graph
1942 call->disconnect_inputs(NULL, C);
1943 C->gvn_replace_by(call, C->top());
1944
1945 // Clean up any MergeMems that feed other MergeMems since the
1946 // optimizer doesn't like that.
1947 if (final_mem->is_MergeMem()) {
1948 Node_List wl;
1949 for (SimpleDUIterator i(final_mem); i.has_next(); i.next()) {
1950 Node* m = i.get();
1951 if (m->is_MergeMem() && !wl.contains(m)) {
1952 wl.push(m);
1953 }
1954 }
1955 while (wl.size() > 0) {
1956 _gvn.transform(wl.pop());
1957 }
1958 }
1959
1960 if (callprojs.fallthrough_catchproj != NULL && !final_ctl->is_top() && do_replaced_nodes) {
1961 replaced_nodes.apply(C, final_ctl);
1962 }
1963 if (!ex_ctl->is_top() && do_replaced_nodes) {
1964 replaced_nodes_exception.apply(C, ex_ctl);
1965 }
1966 }
1967
1968
1969 //------------------------------increment_counter------------------------------
1970 // for statistics: increment a VM counter by 1
1971
1972 void GraphKit::increment_counter(address counter_addr) {
1973 Node* adr1 = makecon(TypeRawPtr::make(counter_addr));
1974 increment_counter(adr1);
1975 }
1976
1977 void GraphKit::increment_counter(Node* counter_addr) {
1978 int adr_type = Compile::AliasIdxRaw;
1979 Node* ctrl = control();
1980 Node* cnt = make_load(ctrl, counter_addr, TypeInt::INT, T_INT, adr_type, MemNode::unordered);
1981 Node* incr = _gvn.transform(new AddINode(cnt, _gvn.intcon(1)));
1982 store_to_memory(ctrl, counter_addr, incr, T_INT, adr_type, MemNode::unordered);
1983 }
1984
1985
1986 //------------------------------uncommon_trap----------------------------------
1987 // Bail out to the interpreter in mid-method. Implemented by calling the
1988 // uncommon_trap blob. This helper function inserts a runtime call with the
1989 // right debug info.
1990 void GraphKit::uncommon_trap(int trap_request,
1991 ciKlass* klass, const char* comment,
1992 bool must_throw,
1993 bool keep_exact_action) {
1994 if (failing()) stop();
1995 if (stopped()) return; // trap reachable?
1996
1997 // Note: If ProfileTraps is true, and if a deopt. actually
1998 // occurs here, the runtime will make sure an MDO exists. There is
1999 // no need to call method()->ensure_method_data() at this point.
2000
2001 // Set the stack pointer to the right value for reexecution:
2002 set_sp(reexecute_sp());
2003
2004 #ifdef ASSERT
2005 if (!must_throw) {
2006 // Make sure the stack has at least enough depth to execute
2007 // the current bytecode.
2008 int inputs, ignored_depth;
2009 if (compute_stack_effects(inputs, ignored_depth)) {
2010 assert(sp() >= inputs, "must have enough JVMS stack to execute %s: sp=%d, inputs=%d",
2011 Bytecodes::name(java_bc()), sp(), inputs);
2012 }
2013 }
2014 #endif
2015
2016 Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);
2017 Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);
2018
2019 switch (action) {
2020 case Deoptimization::Action_maybe_recompile:
2021 case Deoptimization::Action_reinterpret:
2022 // Temporary fix for 6529811 to allow virtual calls to be sure they
2023 // get the chance to go from mono->bi->mega
2024 if (!keep_exact_action &&
2025 Deoptimization::trap_request_index(trap_request) < 0 &&
2026 too_many_recompiles(reason)) {
2027 // This BCI is causing too many recompilations.
2028 if (C->log() != NULL) {
2029 C->log()->elem("observe that='trap_action_change' reason='%s' from='%s' to='none'",
2030 Deoptimization::trap_reason_name(reason),
2031 Deoptimization::trap_action_name(action));
2032 }
2033 action = Deoptimization::Action_none;
2034 trap_request = Deoptimization::make_trap_request(reason, action);
2035 } else {
2036 C->set_trap_can_recompile(true);
2037 }
2038 break;
2039 case Deoptimization::Action_make_not_entrant:
2040 C->set_trap_can_recompile(true);
2041 break;
2042 case Deoptimization::Action_none:
2043 case Deoptimization::Action_make_not_compilable:
2044 break;
2045 default:
2046 #ifdef ASSERT
2047 fatal("unknown action %d: %s", action, Deoptimization::trap_action_name(action));
2048 #endif
2049 break;
2050 }
2051
2052 if (TraceOptoParse) {
2053 char buf[100];
2054 tty->print_cr("Uncommon trap %s at bci:%d",
2055 Deoptimization::format_trap_request(buf, sizeof(buf),
2056 trap_request), bci());
2057 }
2058
2059 CompileLog* log = C->log();
2060 if (log != NULL) {
2061 int kid = (klass == NULL)? -1: log->identify(klass);
2062 log->begin_elem("uncommon_trap bci='%d'", bci());
2063 char buf[100];
2064 log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),
2065 trap_request));
2066 if (kid >= 0) log->print(" klass='%d'", kid);
2067 if (comment != NULL) log->print(" comment='%s'", comment);
2068 log->end_elem();
2069 }
2070
2071 // Make sure any guarding test views this path as very unlikely
2072 Node *i0 = control()->in(0);
2073 if (i0 != NULL && i0->is_If()) { // Found a guarding if test?
2074 IfNode *iff = i0->as_If();
2075 float f = iff->_prob; // Get prob
2076 if (control()->Opcode() == Op_IfTrue) {
2077 if (f > PROB_UNLIKELY_MAG(4))
2078 iff->_prob = PROB_MIN;
2079 } else {
2080 if (f < PROB_LIKELY_MAG(4))
2081 iff->_prob = PROB_MAX;
2082 }
2083 }
2084
2085 // Clear out dead values from the debug info.
2086 kill_dead_locals();
2087
2088 // Now insert the uncommon trap subroutine call
2089 address call_addr = SharedRuntime::uncommon_trap_blob()->entry_point();
2090 const TypePtr* no_memory_effects = NULL;
2091 // Pass the index of the class to be loaded
2092 Node* call = make_runtime_call(RC_NO_LEAF | RC_UNCOMMON |
2093 (must_throw ? RC_MUST_THROW : 0),
2094 OptoRuntime::uncommon_trap_Type(),
2095 call_addr, "uncommon_trap", no_memory_effects,
2096 intcon(trap_request));
2097 assert(call->as_CallStaticJava()->uncommon_trap_request() == trap_request,
2098 "must extract request correctly from the graph");
2099 assert(trap_request != 0, "zero value reserved by uncommon_trap_request");
2100
2101 call->set_req(TypeFunc::ReturnAdr, returnadr());
2102 // The debug info is the only real input to this call.
2103
2104 // Halt-and-catch fire here. The above call should never return!
2105 HaltNode* halt = new HaltNode(control(), frameptr());
2106 _gvn.set_type_bottom(halt);
2107 root()->add_req(halt);
2108
2109 stop_and_kill_map();
2110 }
2111
2112
2113 //--------------------------just_allocated_object------------------------------
2114 // Report the object that was just allocated.
2115 // It must be the case that there are no intervening safepoints.
2116 // We use this to determine if an object is so "fresh" that
2117 // it does not require card marks.
2118 Node* GraphKit::just_allocated_object(Node* current_control) {
2119 if (C->recent_alloc_ctl() == current_control)
2120 return C->recent_alloc_obj();
2121 return NULL;
2122 }
2123
2124
2125 void GraphKit::round_double_arguments(ciMethod* dest_method) {
2126 // (Note: TypeFunc::make has a cache that makes this fast.)
2127 const TypeFunc* tf = TypeFunc::make(dest_method);
2128 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2129 for (int j = 0; j < nargs; j++) {
2130 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2131 if( targ->basic_type() == T_DOUBLE ) {
2132 // If any parameters are doubles, they must be rounded before
2133 // the call, dstore_rounding does gvn.transform
2134 Node *arg = argument(j);
2135 arg = dstore_rounding(arg);
2136 set_argument(j, arg);
2137 }
2138 }
2139 }
2140
2141 /**
2142 * Record profiling data exact_kls for Node n with the type system so
2143 * that it can propagate it (speculation)
2144 *
2145 * @param n node that the type applies to
2146 * @param exact_kls type from profiling
2147 * @param maybe_null did profiling see null?
2148 *
2149 * @return node with improved type
2150 */
2151 Node* GraphKit::record_profile_for_speculation(Node* n, ciKlass* exact_kls, ProfilePtrKind ptr_kind) {
2152 const Type* current_type = _gvn.type(n);
2153 assert(UseTypeSpeculation, "type speculation must be on");
2154
2155 const TypePtr* speculative = current_type->speculative();
2156
2157 // Should the klass from the profile be recorded in the speculative type?
2158 if (current_type->would_improve_type(exact_kls, jvms()->depth())) {
2159 const TypeKlassPtr* tklass = TypeKlassPtr::make(exact_kls);
2160 const TypeOopPtr* xtype = tklass->as_instance_type();
2161 assert(xtype->klass_is_exact(), "Should be exact");
2162 // Any reason to believe n is not null (from this profiling or a previous one)?
2163 assert(ptr_kind != ProfileAlwaysNull, "impossible here");
2164 const TypePtr* ptr = (ptr_kind == ProfileMaybeNull && current_type->speculative_maybe_null()) ? TypePtr::BOTTOM : TypePtr::NOTNULL;
2165 // record the new speculative type's depth
2166 speculative = xtype->cast_to_ptr_type(ptr->ptr())->is_ptr();
2167 speculative = speculative->with_inline_depth(jvms()->depth());
2168 } else if (current_type->would_improve_ptr(ptr_kind)) {
2169 // Profiling report that null was never seen so we can change the
2170 // speculative type to non null ptr.
2171 if (ptr_kind == ProfileAlwaysNull) {
2172 speculative = TypePtr::NULL_PTR;
2173 } else {
2174 assert(ptr_kind == ProfileNeverNull, "nothing else is an improvement");
2175 const TypePtr* ptr = TypePtr::NOTNULL;
2176 if (speculative != NULL) {
2177 speculative = speculative->cast_to_ptr_type(ptr->ptr())->is_ptr();
2178 } else {
2179 speculative = ptr;
2180 }
2181 }
2182 }
2183
2184 if (speculative != current_type->speculative()) {
2185 // Build a type with a speculative type (what we think we know
2186 // about the type but will need a guard when we use it)
2187 const TypeOopPtr* spec_type = TypeOopPtr::make(TypePtr::BotPTR, Type::OffsetBot, TypeOopPtr::InstanceBot, speculative);
2188 // We're changing the type, we need a new CheckCast node to carry
2189 // the new type. The new type depends on the control: what
2190 // profiling tells us is only valid from here as far as we can
2191 // tell.
2192 Node* cast = new CheckCastPPNode(control(), n, current_type->remove_speculative()->join_speculative(spec_type));
2193 cast = _gvn.transform(cast);
2194 replace_in_map(n, cast);
2195 n = cast;
2196 }
2197
2198 return n;
2199 }
2200
2201 /**
2202 * Record profiling data from receiver profiling at an invoke with the
2203 * type system so that it can propagate it (speculation)
2204 *
2205 * @param n receiver node
2206 *
2207 * @return node with improved type
2208 */
2209 Node* GraphKit::record_profiled_receiver_for_speculation(Node* n) {
2210 if (!UseTypeSpeculation) {
2211 return n;
2212 }
2213 ciKlass* exact_kls = profile_has_unique_klass();
2214 ProfilePtrKind ptr_kind = ProfileMaybeNull;
2215 if ((java_bc() == Bytecodes::_checkcast ||
2216 java_bc() == Bytecodes::_instanceof ||
2217 java_bc() == Bytecodes::_aastore) &&
2218 method()->method_data()->is_mature()) {
2219 ciProfileData* data = method()->method_data()->bci_to_data(bci());
2220 if (data != NULL) {
2221 if (!data->as_BitData()->null_seen()) {
2222 ptr_kind = ProfileNeverNull;
2223 } else {
2224 assert(data->is_ReceiverTypeData(), "bad profile data type");
2225 ciReceiverTypeData* call = (ciReceiverTypeData*)data->as_ReceiverTypeData();
2226 uint i = 0;
2227 for (; i < call->row_limit(); i++) {
2228 ciKlass* receiver = call->receiver(i);
2229 if (receiver != NULL) {
2230 break;
2231 }
2232 }
2233 ptr_kind = (i == call->row_limit()) ? ProfileAlwaysNull : ProfileMaybeNull;
2234 }
2235 }
2236 }
2237 return record_profile_for_speculation(n, exact_kls, ptr_kind);
2238 }
2239
2240 /**
2241 * Record profiling data from argument profiling at an invoke with the
2242 * type system so that it can propagate it (speculation)
2243 *
2244 * @param dest_method target method for the call
2245 * @param bc what invoke bytecode is this?
2246 */
2247 void GraphKit::record_profiled_arguments_for_speculation(ciMethod* dest_method, Bytecodes::Code bc) {
2248 if (!UseTypeSpeculation) {
2249 return;
2250 }
2251 const TypeFunc* tf = TypeFunc::make(dest_method);
2252 int nargs = tf->domain()->cnt() - TypeFunc::Parms;
2253 int skip = Bytecodes::has_receiver(bc) ? 1 : 0;
2254 for (int j = skip, i = 0; j < nargs && i < TypeProfileArgsLimit; j++) {
2255 const Type *targ = tf->domain()->field_at(j + TypeFunc::Parms);
2256 if (targ->basic_type() == T_OBJECT || targ->basic_type() == T_ARRAY) {
2257 ProfilePtrKind ptr_kind = ProfileMaybeNull;
2258 ciKlass* better_type = NULL;
2259 if (method()->argument_profiled_type(bci(), i, better_type, ptr_kind)) {
2260 record_profile_for_speculation(argument(j), better_type, ptr_kind);
2261 }
2262 i++;
2263 }
2264 }
2265 }
2266
2267 /**
2268 * Record profiling data from parameter profiling at an invoke with
2269 * the type system so that it can propagate it (speculation)
2270 */
2271 void GraphKit::record_profiled_parameters_for_speculation() {
2272 if (!UseTypeSpeculation) {
2273 return;
2274 }
2275 for (int i = 0, j = 0; i < method()->arg_size() ; i++) {
2276 if (_gvn.type(local(i))->isa_oopptr()) {
2277 ProfilePtrKind ptr_kind = ProfileMaybeNull;
2278 ciKlass* better_type = NULL;
2279 if (method()->parameter_profiled_type(j, better_type, ptr_kind)) {
2280 record_profile_for_speculation(local(i), better_type, ptr_kind);
2281 }
2282 j++;
2283 }
2284 }
2285 }
2286
2287 /**
2288 * Record profiling data from return value profiling at an invoke with
2289 * the type system so that it can propagate it (speculation)
2290 */
2291 void GraphKit::record_profiled_return_for_speculation() {
2292 if (!UseTypeSpeculation) {
2293 return;
2294 }
2295 ProfilePtrKind ptr_kind = ProfileMaybeNull;
2296 ciKlass* better_type = NULL;
2297 if (method()->return_profiled_type(bci(), better_type, ptr_kind)) {
2298 // If profiling reports a single type for the return value,
2299 // feed it to the type system so it can propagate it as a
2300 // speculative type
2301 record_profile_for_speculation(stack(sp()-1), better_type, ptr_kind);
2302 }
2303 }
2304
2305 void GraphKit::round_double_result(ciMethod* dest_method) {
2306 // A non-strict method may return a double value which has an extended
2307 // exponent, but this must not be visible in a caller which is 'strict'
2308 // If a strict caller invokes a non-strict callee, round a double result
2309
2310 BasicType result_type = dest_method->return_type()->basic_type();
2311 assert( method() != NULL, "must have caller context");
2312 if( result_type == T_DOUBLE && method()->is_strict() && !dest_method->is_strict() ) {
2313 // Destination method's return value is on top of stack
2314 // dstore_rounding() does gvn.transform
2315 Node *result = pop_pair();
2316 result = dstore_rounding(result);
2317 push_pair(result);
2318 }
2319 }
2320
2321 // rounding for strict float precision conformance
2322 Node* GraphKit::precision_rounding(Node* n) {
2323 return UseStrictFP && _method->flags().is_strict()
2324 && UseSSE == 0 && Matcher::strict_fp_requires_explicit_rounding
2325 ? _gvn.transform( new RoundFloatNode(0, n) )
2326 : n;
2327 }
2328
2329 // rounding for strict double precision conformance
2330 Node* GraphKit::dprecision_rounding(Node *n) {
2331 return UseStrictFP && _method->flags().is_strict()
2332 && UseSSE <= 1 && Matcher::strict_fp_requires_explicit_rounding
2333 ? _gvn.transform( new RoundDoubleNode(0, n) )
2334 : n;
2335 }
2336
2337 // rounding for non-strict double stores
2338 Node* GraphKit::dstore_rounding(Node* n) {
2339 return Matcher::strict_fp_requires_explicit_rounding
2340 && UseSSE <= 1
2341 ? _gvn.transform( new RoundDoubleNode(0, n) )
2342 : n;
2343 }
2344
2345 //=============================================================================
2346 // Generate a fast path/slow path idiom. Graph looks like:
2347 // [foo] indicates that 'foo' is a parameter
2348 //
2349 // [in] NULL
2350 // \ /
2351 // CmpP
2352 // Bool ne
2353 // If
2354 // / \
2355 // True False-<2>
2356 // / |
2357 // / cast_not_null
2358 // Load | | ^
2359 // [fast_test] | |
2360 // gvn to opt_test | |
2361 // / \ | <1>
2362 // True False |
2363 // | \\ |
2364 // [slow_call] \[fast_result]
2365 // Ctl Val \ \
2366 // | \ \
2367 // Catch <1> \ \
2368 // / \ ^ \ \
2369 // Ex No_Ex | \ \
2370 // | \ \ | \ <2> \
2371 // ... \ [slow_res] | | \ [null_result]
2372 // \ \--+--+--- | |
2373 // \ | / \ | /
2374 // --------Region Phi
2375 //
2376 //=============================================================================
2377 // Code is structured as a series of driver functions all called 'do_XXX' that
2378 // call a set of helper functions. Helper functions first, then drivers.
2379
2380 //------------------------------null_check_oop---------------------------------
2381 // Null check oop. Set null-path control into Region in slot 3.
2382 // Make a cast-not-nullness use the other not-null control. Return cast.
2383 Node* GraphKit::null_check_oop(Node* value, Node* *null_control,
2384 bool never_see_null,
2385 bool safe_for_replace,
2386 bool speculative) {
2387 // Initial NULL check taken path
2388 (*null_control) = top();
2389 Node* cast = null_check_common(value, T_OBJECT, false, null_control, speculative);
2390
2391 // Generate uncommon_trap:
2392 if (never_see_null && (*null_control) != top()) {
2393 // If we see an unexpected null at a check-cast we record it and force a
2394 // recompile; the offending check-cast will be compiled to handle NULLs.
2395 // If we see more than one offending BCI, then all checkcasts in the
2396 // method will be compiled to handle NULLs.
2397 PreserveJVMState pjvms(this);
2398 set_control(*null_control);
2399 replace_in_map(value, null());
2400 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculative);
2401 uncommon_trap(reason,
2402 Deoptimization::Action_make_not_entrant);
2403 (*null_control) = top(); // NULL path is dead
2404 }
2405 if ((*null_control) == top() && safe_for_replace) {
2406 replace_in_map(value, cast);
2407 }
2408
2409 // Cast away null-ness on the result
2410 return cast;
2411 }
2412
2413 //------------------------------opt_iff----------------------------------------
2414 // Optimize the fast-check IfNode. Set the fast-path region slot 2.
2415 // Return slow-path control.
2416 Node* GraphKit::opt_iff(Node* region, Node* iff) {
2417 IfNode *opt_iff = _gvn.transform(iff)->as_If();
2418
2419 // Fast path taken; set region slot 2
2420 Node *fast_taken = _gvn.transform( new IfFalseNode(opt_iff) );
2421 region->init_req(2,fast_taken); // Capture fast-control
2422
2423 // Fast path not-taken, i.e. slow path
2424 Node *slow_taken = _gvn.transform( new IfTrueNode(opt_iff) );
2425 return slow_taken;
2426 }
2427
2428 //-----------------------------make_runtime_call-------------------------------
2429 Node* GraphKit::make_runtime_call(int flags,
2430 const TypeFunc* call_type, address call_addr,
2431 const char* call_name,
2432 const TypePtr* adr_type,
2433 // The following parms are all optional.
2434 // The first NULL ends the list.
2435 Node* parm0, Node* parm1,
2436 Node* parm2, Node* parm3,
2437 Node* parm4, Node* parm5,
2438 Node* parm6, Node* parm7) {
2439 // Slow-path call
2440 bool is_leaf = !(flags & RC_NO_LEAF);
2441 bool has_io = (!is_leaf && !(flags & RC_NO_IO));
2442 if (call_name == NULL) {
2443 assert(!is_leaf, "must supply name for leaf");
2444 call_name = OptoRuntime::stub_name(call_addr);
2445 }
2446 CallNode* call;
2447 if (!is_leaf) {
2448 call = new CallStaticJavaNode(call_type, call_addr, call_name,
2449 bci(), adr_type);
2450 } else if (flags & RC_NO_FP) {
2451 call = new CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);
2452 } else {
2453 call = new CallLeafNode(call_type, call_addr, call_name, adr_type);
2454 }
2455
2456 // The following is similar to set_edges_for_java_call,
2457 // except that the memory effects of the call are restricted to AliasIdxRaw.
2458
2459 // Slow path call has no side-effects, uses few values
2460 bool wide_in = !(flags & RC_NARROW_MEM);
2461 bool wide_out = (C->get_alias_index(adr_type) == Compile::AliasIdxBot);
2462
2463 Node* prev_mem = NULL;
2464 if (wide_in) {
2465 prev_mem = set_predefined_input_for_runtime_call(call);
2466 } else {
2467 assert(!wide_out, "narrow in => narrow out");
2468 Node* narrow_mem = memory(adr_type);
2469 prev_mem = reset_memory();
2470 map()->set_memory(narrow_mem);
2471 set_predefined_input_for_runtime_call(call);
2472 }
2473
2474 // Hook each parm in order. Stop looking at the first NULL.
2475 if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);
2476 if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);
2477 if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);
2478 if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);
2479 if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);
2480 if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);
2481 if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);
2482 if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);
2483 /* close each nested if ===> */ } } } } } } } }
2484 assert(call->in(call->req()-1) != NULL, "must initialize all parms");
2485
2486 if (!is_leaf) {
2487 // Non-leaves can block and take safepoints:
2488 add_safepoint_edges(call, ((flags & RC_MUST_THROW) != 0));
2489 }
2490 // Non-leaves can throw exceptions:
2491 if (has_io) {
2492 call->set_req(TypeFunc::I_O, i_o());
2493 }
2494
2495 if (flags & RC_UNCOMMON) {
2496 // Set the count to a tiny probability. Cf. Estimate_Block_Frequency.
2497 // (An "if" probability corresponds roughly to an unconditional count.
2498 // Sort of.)
2499 call->set_cnt(PROB_UNLIKELY_MAG(4));
2500 }
2501
2502 Node* c = _gvn.transform(call);
2503 assert(c == call, "cannot disappear");
2504
2505 if (wide_out) {
2506 // Slow path call has full side-effects.
2507 set_predefined_output_for_runtime_call(call);
2508 } else {
2509 // Slow path call has few side-effects, and/or sets few values.
2510 set_predefined_output_for_runtime_call(call, prev_mem, adr_type);
2511 }
2512
2513 if (has_io) {
2514 set_i_o(_gvn.transform(new ProjNode(call, TypeFunc::I_O)));
2515 }
2516 return call;
2517
2518 }
2519
2520 //------------------------------merge_memory-----------------------------------
2521 // Merge memory from one path into the current memory state.
2522 void GraphKit::merge_memory(Node* new_mem, Node* region, int new_path) {
2523 for (MergeMemStream mms(merged_memory(), new_mem->as_MergeMem()); mms.next_non_empty2(); ) {
2524 Node* old_slice = mms.force_memory();
2525 Node* new_slice = mms.memory2();
2526 if (old_slice != new_slice) {
2527 PhiNode* phi;
2528 if (old_slice->is_Phi() && old_slice->as_Phi()->region() == region) {
2529 if (mms.is_empty()) {
2530 // clone base memory Phi's inputs for this memory slice
2531 assert(old_slice == mms.base_memory(), "sanity");
2532 phi = PhiNode::make(region, NULL, Type::MEMORY, mms.adr_type(C));
2533 _gvn.set_type(phi, Type::MEMORY);
2534 for (uint i = 1; i < phi->req(); i++) {
2535 phi->init_req(i, old_slice->in(i));
2536 }
2537 } else {
2538 phi = old_slice->as_Phi(); // Phi was generated already
2539 }
2540 } else {
2541 phi = PhiNode::make(region, old_slice, Type::MEMORY, mms.adr_type(C));
2542 _gvn.set_type(phi, Type::MEMORY);
2543 }
2544 phi->set_req(new_path, new_slice);
2545 mms.set_memory(phi);
2546 }
2547 }
2548 }
2549
2550 //------------------------------make_slow_call_ex------------------------------
2551 // Make the exception handler hookups for the slow call
2552 void GraphKit::make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj, bool deoptimize) {
2553 if (stopped()) return;
2554
2555 // Make a catch node with just two handlers: fall-through and catch-all
2556 Node* i_o = _gvn.transform( new ProjNode(call, TypeFunc::I_O, separate_io_proj) );
2557 Node* catc = _gvn.transform( new CatchNode(control(), i_o, 2) );
2558 Node* norm = _gvn.transform( new CatchProjNode(catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci) );
2559 Node* excp = _gvn.transform( new CatchProjNode(catc, CatchProjNode::catch_all_index, CatchProjNode::no_handler_bci) );
2560
2561 { PreserveJVMState pjvms(this);
2562 set_control(excp);
2563 set_i_o(i_o);
2564
2565 if (excp != top()) {
2566 if (deoptimize) {
2567 // Deoptimize if an exception is caught. Don't construct exception state in this case.
2568 uncommon_trap(Deoptimization::Reason_unhandled,
2569 Deoptimization::Action_none);
2570 } else {
2571 // Create an exception state also.
2572 // Use an exact type if the caller has specified a specific exception.
2573 const Type* ex_type = TypeOopPtr::make_from_klass_unique(ex_klass)->cast_to_ptr_type(TypePtr::NotNull);
2574 Node* ex_oop = new CreateExNode(ex_type, control(), i_o);
2575 add_exception_state(make_exception_state(_gvn.transform(ex_oop)));
2576 }
2577 }
2578 }
2579
2580 // Get the no-exception control from the CatchNode.
2581 set_control(norm);
2582 }
2583
2584 static IfNode* gen_subtype_check_compare(Node* ctrl, Node* in1, Node* in2, BoolTest::mask test, float p, PhaseGVN* gvn, BasicType bt) {
2585 Node* cmp = NULL;
2586 switch(bt) {
2587 case T_INT: cmp = new CmpINode(in1, in2); break;
2588 case T_ADDRESS: cmp = new CmpPNode(in1, in2); break;
2589 default: fatal("unexpected comparison type %s", type2name(bt));
2590 }
2591 gvn->transform(cmp);
2592 Node* bol = gvn->transform(new BoolNode(cmp, test));
2593 IfNode* iff = new IfNode(ctrl, bol, p, COUNT_UNKNOWN);
2594 gvn->transform(iff);
2595 if (!bol->is_Con()) gvn->record_for_igvn(iff);
2596 return iff;
2597 }
2598
2599
2600 //-------------------------------gen_subtype_check-----------------------------
2601 // Generate a subtyping check. Takes as input the subtype and supertype.
2602 // Returns 2 values: sets the default control() to the true path and returns
2603 // the false path. Only reads invariant memory; sets no (visible) memory.
2604 // The PartialSubtypeCheckNode sets the hidden 1-word cache in the encoding
2605 // but that's not exposed to the optimizer. This call also doesn't take in an
2606 // Object; if you wish to check an Object you need to load the Object's class
2607 // prior to coming here.
2608 Node* Phase::gen_subtype_check(Node* subklass, Node* superklass, Node** ctrl, MergeMemNode* mem, PhaseGVN* gvn) {
2609 Compile* C = gvn->C;
2610
2611 if ((*ctrl)->is_top()) {
2612 return C->top();
2613 }
2614
2615 // Fast check for identical types, perhaps identical constants.
2616 // The types can even be identical non-constants, in cases
2617 // involving Array.newInstance, Object.clone, etc.
2618 if (subklass == superklass)
2619 return C->top(); // false path is dead; no test needed.
2620
2621 if (gvn->type(superklass)->singleton()) {
2622 ciKlass* superk = gvn->type(superklass)->is_klassptr()->klass();
2623 ciKlass* subk = gvn->type(subklass)->is_klassptr()->klass();
2624
2625 // In the common case of an exact superklass, try to fold up the
2626 // test before generating code. You may ask, why not just generate
2627 // the code and then let it fold up? The answer is that the generated
2628 // code will necessarily include null checks, which do not always
2629 // completely fold away. If they are also needless, then they turn
2630 // into a performance loss. Example:
2631 // Foo[] fa = blah(); Foo x = fa[0]; fa[1] = x;
2632 // Here, the type of 'fa' is often exact, so the store check
2633 // of fa[1]=x will fold up, without testing the nullness of x.
2634 switch (C->static_subtype_check(superk, subk)) {
2635 case Compile::SSC_always_false:
2636 {
2637 Node* always_fail = *ctrl;
2638 *ctrl = gvn->C->top();
2639 return always_fail;
2640 }
2641 case Compile::SSC_always_true:
2642 return C->top();
2643 case Compile::SSC_easy_test:
2644 {
2645 // Just do a direct pointer compare and be done.
2646 IfNode* iff = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_STATIC_FREQUENT, gvn, T_ADDRESS);
2647 *ctrl = gvn->transform(new IfTrueNode(iff));
2648 return gvn->transform(new IfFalseNode(iff));
2649 }
2650 case Compile::SSC_full_test:
2651 break;
2652 default:
2653 ShouldNotReachHere();
2654 }
2655 }
2656
2657 // %%% Possible further optimization: Even if the superklass is not exact,
2658 // if the subklass is the unique subtype of the superklass, the check
2659 // will always succeed. We could leave a dependency behind to ensure this.
2660
2661 // First load the super-klass's check-offset
2662 Node *p1 = gvn->transform(new AddPNode(superklass, superklass, gvn->MakeConX(in_bytes(Klass::super_check_offset_offset()))));
2663 Node* m = mem->memory_at(C->get_alias_index(gvn->type(p1)->is_ptr()));
2664 Node *chk_off = gvn->transform(new LoadINode(NULL, m, p1, gvn->type(p1)->is_ptr(), TypeInt::INT, MemNode::unordered));
2665 int cacheoff_con = in_bytes(Klass::secondary_super_cache_offset());
2666 bool might_be_cache = (gvn->find_int_con(chk_off, cacheoff_con) == cacheoff_con);
2667
2668 // Load from the sub-klass's super-class display list, or a 1-word cache of
2669 // the secondary superclass list, or a failing value with a sentinel offset
2670 // if the super-klass is an interface or exceptionally deep in the Java
2671 // hierarchy and we have to scan the secondary superclass list the hard way.
2672 // Worst-case type is a little odd: NULL is allowed as a result (usually
2673 // klass loads can never produce a NULL).
2674 Node *chk_off_X = chk_off;
2675 #ifdef _LP64
2676 chk_off_X = gvn->transform(new ConvI2LNode(chk_off_X));
2677 #endif
2678 Node *p2 = gvn->transform(new AddPNode(subklass,subklass,chk_off_X));
2679 // For some types like interfaces the following loadKlass is from a 1-word
2680 // cache which is mutable so can't use immutable memory. Other
2681 // types load from the super-class display table which is immutable.
2682 m = mem->memory_at(C->get_alias_index(gvn->type(p2)->is_ptr()));
2683 Node *kmem = might_be_cache ? m : C->immutable_memory();
2684 Node *nkls = gvn->transform(LoadKlassNode::make(*gvn, NULL, kmem, p2, gvn->type(p2)->is_ptr(), TypeKlassPtr::OBJECT_OR_NULL));
2685
2686 // Compile speed common case: ARE a subtype and we canNOT fail
2687 if( superklass == nkls )
2688 return C->top(); // false path is dead; no test needed.
2689
2690 // See if we get an immediate positive hit. Happens roughly 83% of the
2691 // time. Test to see if the value loaded just previously from the subklass
2692 // is exactly the superklass.
2693 IfNode *iff1 = gen_subtype_check_compare(*ctrl, superklass, nkls, BoolTest::eq, PROB_LIKELY(0.83f), gvn, T_ADDRESS);
2694 Node *iftrue1 = gvn->transform( new IfTrueNode (iff1));
2695 *ctrl = gvn->transform(new IfFalseNode(iff1));
2696
2697 // Compile speed common case: Check for being deterministic right now. If
2698 // chk_off is a constant and not equal to cacheoff then we are NOT a
2699 // subklass. In this case we need exactly the 1 test above and we can
2700 // return those results immediately.
2701 if (!might_be_cache) {
2702 Node* not_subtype_ctrl = *ctrl;
2703 *ctrl = iftrue1; // We need exactly the 1 test above
2704 return not_subtype_ctrl;
2705 }
2706
2707 // Gather the various success & failures here
2708 RegionNode *r_ok_subtype = new RegionNode(4);
2709 gvn->record_for_igvn(r_ok_subtype);
2710 RegionNode *r_not_subtype = new RegionNode(3);
2711 gvn->record_for_igvn(r_not_subtype);
2712
2713 r_ok_subtype->init_req(1, iftrue1);
2714
2715 // Check for immediate negative hit. Happens roughly 11% of the time (which
2716 // is roughly 63% of the remaining cases). Test to see if the loaded
2717 // check-offset points into the subklass display list or the 1-element
2718 // cache. If it points to the display (and NOT the cache) and the display
2719 // missed then it's not a subtype.
2720 Node *cacheoff = gvn->intcon(cacheoff_con);
2721 IfNode *iff2 = gen_subtype_check_compare(*ctrl, chk_off, cacheoff, BoolTest::ne, PROB_LIKELY(0.63f), gvn, T_INT);
2722 r_not_subtype->init_req(1, gvn->transform(new IfTrueNode (iff2)));
2723 *ctrl = gvn->transform(new IfFalseNode(iff2));
2724
2725 // Check for self. Very rare to get here, but it is taken 1/3 the time.
2726 // No performance impact (too rare) but allows sharing of secondary arrays
2727 // which has some footprint reduction.
2728 IfNode *iff3 = gen_subtype_check_compare(*ctrl, subklass, superklass, BoolTest::eq, PROB_LIKELY(0.36f), gvn, T_ADDRESS);
2729 r_ok_subtype->init_req(2, gvn->transform(new IfTrueNode(iff3)));
2730 *ctrl = gvn->transform(new IfFalseNode(iff3));
2731
2732 // -- Roads not taken here: --
2733 // We could also have chosen to perform the self-check at the beginning
2734 // of this code sequence, as the assembler does. This would not pay off
2735 // the same way, since the optimizer, unlike the assembler, can perform
2736 // static type analysis to fold away many successful self-checks.
2737 // Non-foldable self checks work better here in second position, because
2738 // the initial primary superclass check subsumes a self-check for most
2739 // types. An exception would be a secondary type like array-of-interface,
2740 // which does not appear in its own primary supertype display.
2741 // Finally, we could have chosen to move the self-check into the
2742 // PartialSubtypeCheckNode, and from there out-of-line in a platform
2743 // dependent manner. But it is worthwhile to have the check here,
2744 // where it can be perhaps be optimized. The cost in code space is
2745 // small (register compare, branch).
2746
2747 // Now do a linear scan of the secondary super-klass array. Again, no real
2748 // performance impact (too rare) but it's gotta be done.
2749 // Since the code is rarely used, there is no penalty for moving it
2750 // out of line, and it can only improve I-cache density.
2751 // The decision to inline or out-of-line this final check is platform
2752 // dependent, and is found in the AD file definition of PartialSubtypeCheck.
2753 Node* psc = gvn->transform(
2754 new PartialSubtypeCheckNode(*ctrl, subklass, superklass));
2755
2756 IfNode *iff4 = gen_subtype_check_compare(*ctrl, psc, gvn->zerocon(T_OBJECT), BoolTest::ne, PROB_FAIR, gvn, T_ADDRESS);
2757 r_not_subtype->init_req(2, gvn->transform(new IfTrueNode (iff4)));
2758 r_ok_subtype ->init_req(3, gvn->transform(new IfFalseNode(iff4)));
2759
2760 // Return false path; set default control to true path.
2761 *ctrl = gvn->transform(r_ok_subtype);
2762 return gvn->transform(r_not_subtype);
2763 }
2764
2765 // Profile-driven exact type check:
2766 Node* GraphKit::type_check_receiver(Node* receiver, ciKlass* klass,
2767 float prob,
2768 Node* *casted_receiver) {
2769 const TypeKlassPtr* tklass = TypeKlassPtr::make(klass);
2770 Node* recv_klass = load_object_klass(receiver);
2771 Node* want_klass = makecon(tklass);
2772 Node* cmp = _gvn.transform( new CmpPNode(recv_klass, want_klass) );
2773 Node* bol = _gvn.transform( new BoolNode(cmp, BoolTest::eq) );
2774 IfNode* iff = create_and_xform_if(control(), bol, prob, COUNT_UNKNOWN);
2775 set_control( _gvn.transform( new IfTrueNode (iff) ));
2776 Node* fail = _gvn.transform( new IfFalseNode(iff) );
2777
2778 const TypeOopPtr* recv_xtype = tklass->as_instance_type();
2779 assert(recv_xtype->klass_is_exact(), "");
2780
2781 // Subsume downstream occurrences of receiver with a cast to
2782 // recv_xtype, since now we know what the type will be.
2783 Node* cast = new CheckCastPPNode(control(), receiver, recv_xtype);
2784 (*casted_receiver) = _gvn.transform(cast);
2785 // (User must make the replace_in_map call.)
2786
2787 return fail;
2788 }
2789
2790
2791 //------------------------------seems_never_null-------------------------------
2792 // Use null_seen information if it is available from the profile.
2793 // If we see an unexpected null at a type check we record it and force a
2794 // recompile; the offending check will be recompiled to handle NULLs.
2795 // If we see several offending BCIs, then all checks in the
2796 // method will be recompiled.
2797 bool GraphKit::seems_never_null(Node* obj, ciProfileData* data, bool& speculating) {
2798 speculating = !_gvn.type(obj)->speculative_maybe_null();
2799 Deoptimization::DeoptReason reason = Deoptimization::reason_null_check(speculating);
2800 if (UncommonNullCast // Cutout for this technique
2801 && obj != null() // And not the -Xcomp stupid case?
2802 && !too_many_traps(reason)
2803 ) {
2804 if (speculating) {
2805 return true;
2806 }
2807 if (data == NULL)
2808 // Edge case: no mature data. Be optimistic here.
2809 return true;
2810 // If the profile has not seen a null, assume it won't happen.
2811 assert(java_bc() == Bytecodes::_checkcast ||
2812 java_bc() == Bytecodes::_instanceof ||
2813 java_bc() == Bytecodes::_aastore, "MDO must collect null_seen bit here");
2814 return !data->as_BitData()->null_seen();
2815 }
2816 speculating = false;
2817 return false;
2818 }
2819
2820 //------------------------maybe_cast_profiled_receiver-------------------------
2821 // If the profile has seen exactly one type, narrow to exactly that type.
2822 // Subsequent type checks will always fold up.
2823 Node* GraphKit::maybe_cast_profiled_receiver(Node* not_null_obj,
2824 ciKlass* require_klass,
2825 ciKlass* spec_klass,
2826 bool safe_for_replace) {
2827 if (!UseTypeProfile || !TypeProfileCasts) return NULL;
2828
2829 Deoptimization::DeoptReason reason = Deoptimization::reason_class_check(spec_klass != NULL);
2830
2831 // Make sure we haven't already deoptimized from this tactic.
2832 if (too_many_traps(reason) || too_many_recompiles(reason))
2833 return NULL;
2834
2835 // (No, this isn't a call, but it's enough like a virtual call
2836 // to use the same ciMethod accessor to get the profile info...)
2837 // If we have a speculative type use it instead of profiling (which
2838 // may not help us)
2839 ciKlass* exact_kls = spec_klass == NULL ? profile_has_unique_klass() : spec_klass;
2840 if (exact_kls != NULL) {// no cast failures here
2841 if (require_klass == NULL ||
2842 C->static_subtype_check(require_klass, exact_kls) == Compile::SSC_always_true) {
2843 // If we narrow the type to match what the type profile sees or
2844 // the speculative type, we can then remove the rest of the
2845 // cast.
2846 // This is a win, even if the exact_kls is very specific,
2847 // because downstream operations, such as method calls,
2848 // will often benefit from the sharper type.
2849 Node* exact_obj = not_null_obj; // will get updated in place...
2850 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2851 &exact_obj);
2852 { PreserveJVMState pjvms(this);
2853 set_control(slow_ctl);
2854 uncommon_trap_exact(reason, Deoptimization::Action_maybe_recompile);
2855 }
2856 if (safe_for_replace) {
2857 replace_in_map(not_null_obj, exact_obj);
2858 }
2859 return exact_obj;
2860 }
2861 // assert(ssc == Compile::SSC_always_true)... except maybe the profile lied to us.
2862 }
2863
2864 return NULL;
2865 }
2866
2867 /**
2868 * Cast obj to type and emit guard unless we had too many traps here
2869 * already
2870 *
2871 * @param obj node being casted
2872 * @param type type to cast the node to
2873 * @param not_null true if we know node cannot be null
2874 */
2875 Node* GraphKit::maybe_cast_profiled_obj(Node* obj,
2876 ciKlass* type,
2877 bool not_null) {
2878 if (stopped()) {
2879 return obj;
2880 }
2881
2882 // type == NULL if profiling tells us this object is always null
2883 if (type != NULL) {
2884 Deoptimization::DeoptReason class_reason = Deoptimization::Reason_speculate_class_check;
2885 Deoptimization::DeoptReason null_reason = Deoptimization::Reason_speculate_null_check;
2886
2887 if (!too_many_traps(null_reason) && !too_many_recompiles(null_reason) &&
2888 !too_many_traps(class_reason) &&
2889 !too_many_recompiles(class_reason)) {
2890 Node* not_null_obj = NULL;
2891 // not_null is true if we know the object is not null and
2892 // there's no need for a null check
2893 if (!not_null) {
2894 Node* null_ctl = top();
2895 not_null_obj = null_check_oop(obj, &null_ctl, true, true, true);
2896 assert(null_ctl->is_top(), "no null control here");
2897 } else {
2898 not_null_obj = obj;
2899 }
2900
2901 Node* exact_obj = not_null_obj;
2902 ciKlass* exact_kls = type;
2903 Node* slow_ctl = type_check_receiver(exact_obj, exact_kls, 1.0,
2904 &exact_obj);
2905 {
2906 PreserveJVMState pjvms(this);
2907 set_control(slow_ctl);
2908 uncommon_trap_exact(class_reason, Deoptimization::Action_maybe_recompile);
2909 }
2910 replace_in_map(not_null_obj, exact_obj);
2911 obj = exact_obj;
2912 }
2913 } else {
2914 if (!too_many_traps(Deoptimization::Reason_null_assert) &&
2915 !too_many_recompiles(Deoptimization::Reason_null_assert)) {
2916 Node* exact_obj = null_assert(obj);
2917 replace_in_map(obj, exact_obj);
2918 obj = exact_obj;
2919 }
2920 }
2921 return obj;
2922 }
2923
2924 //-------------------------------gen_instanceof--------------------------------
2925 // Generate an instance-of idiom. Used by both the instance-of bytecode
2926 // and the reflective instance-of call.
2927 Node* GraphKit::gen_instanceof(Node* obj, Node* superklass, bool safe_for_replace) {
2928 kill_dead_locals(); // Benefit all the uncommon traps
2929 assert( !stopped(), "dead parse path should be checked in callers" );
2930 assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()),
2931 "must check for not-null not-dead klass in callers");
2932
2933 // Make the merge point
2934 enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT };
2935 RegionNode* region = new RegionNode(PATH_LIMIT);
2936 Node* phi = new PhiNode(region, TypeInt::BOOL);
2937 C->set_has_split_ifs(true); // Has chance for split-if optimization
2938
2939 ciProfileData* data = NULL;
2940 if (java_bc() == Bytecodes::_instanceof) { // Only for the bytecode
2941 data = method()->method_data()->bci_to_data(bci());
2942 }
2943 bool speculative_not_null = false;
2944 bool never_see_null = (ProfileDynamicTypes // aggressive use of profile
2945 && seems_never_null(obj, data, speculative_not_null));
2946
2947 // Null check; get casted pointer; set region slot 3
2948 Node* null_ctl = top();
2949 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
2950
2951 // If not_null_obj is dead, only null-path is taken
2952 if (stopped()) { // Doing instance-of on a NULL?
2953 set_control(null_ctl);
2954 return intcon(0);
2955 }
2956 region->init_req(_null_path, null_ctl);
2957 phi ->init_req(_null_path, intcon(0)); // Set null path value
2958 if (null_ctl == top()) {
2959 // Do this eagerly, so that pattern matches like is_diamond_phi
2960 // will work even during parsing.
2961 assert(_null_path == PATH_LIMIT-1, "delete last");
2962 region->del_req(_null_path);
2963 phi ->del_req(_null_path);
2964 }
2965
2966 // Do we know the type check always succeed?
2967 bool known_statically = false;
2968 if (_gvn.type(superklass)->singleton()) {
2969 ciKlass* superk = _gvn.type(superklass)->is_klassptr()->klass();
2970 ciKlass* subk = _gvn.type(obj)->is_oopptr()->klass();
2971 if (subk != NULL && subk->is_loaded()) {
2972 int static_res = C->static_subtype_check(superk, subk);
2973 known_statically = (static_res == Compile::SSC_always_true || static_res == Compile::SSC_always_false);
2974 }
2975 }
2976
2977 if (!known_statically) {
2978 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
2979 // We may not have profiling here or it may not help us. If we
2980 // have a speculative type use it to perform an exact cast.
2981 ciKlass* spec_obj_type = obj_type->speculative_type();
2982 if (spec_obj_type != NULL || (ProfileDynamicTypes && data != NULL)) {
2983 Node* cast_obj = maybe_cast_profiled_receiver(not_null_obj, NULL, spec_obj_type, safe_for_replace);
2984 if (stopped()) { // Profile disagrees with this path.
2985 set_control(null_ctl); // Null is the only remaining possibility.
2986 return intcon(0);
2987 }
2988 if (cast_obj != NULL) {
2989 not_null_obj = cast_obj;
2990 }
2991 }
2992 }
2993
2994 // Load the object's klass
2995 Node* obj_klass = load_object_klass(not_null_obj);
2996
2997 // Generate the subtype check
2998 Node* not_subtype_ctrl = gen_subtype_check(obj_klass, superklass);
2999
3000 // Plug in the success path to the general merge in slot 1.
3001 region->init_req(_obj_path, control());
3002 phi ->init_req(_obj_path, intcon(1));
3003
3004 // Plug in the failing path to the general merge in slot 2.
3005 region->init_req(_fail_path, not_subtype_ctrl);
3006 phi ->init_req(_fail_path, intcon(0));
3007
3008 // Return final merged results
3009 set_control( _gvn.transform(region) );
3010 record_for_igvn(region);
3011
3012 // If we know the type check always succeeds then we don't use the
3013 // profiling data at this bytecode. Don't lose it, feed it to the
3014 // type system as a speculative type.
3015 if (safe_for_replace) {
3016 Node* casted_obj = record_profiled_receiver_for_speculation(obj);
3017 replace_in_map(obj, casted_obj);
3018 }
3019
3020 return _gvn.transform(phi);
3021 }
3022
3023 //-------------------------------gen_checkcast---------------------------------
3024 // Generate a checkcast idiom. Used by both the checkcast bytecode and the
3025 // array store bytecode. Stack must be as-if BEFORE doing the bytecode so the
3026 // uncommon-trap paths work. Adjust stack after this call.
3027 // If failure_control is supplied and not null, it is filled in with
3028 // the control edge for the cast failure. Otherwise, an appropriate
3029 // uncommon trap or exception is thrown.
3030 Node* GraphKit::gen_checkcast(Node *obj, Node* superklass,
3031 Node* *failure_control) {
3032 kill_dead_locals(); // Benefit all the uncommon traps
3033 const TypeKlassPtr *tk = _gvn.type(superklass)->is_klassptr();
3034 const Type *toop = TypeOopPtr::make_from_klass(tk->klass());
3035
3036 // Fast cutout: Check the case that the cast is vacuously true.
3037 // This detects the common cases where the test will short-circuit
3038 // away completely. We do this before we perform the null check,
3039 // because if the test is going to turn into zero code, we don't
3040 // want a residual null check left around. (Causes a slowdown,
3041 // for example, in some objArray manipulations, such as a[i]=a[j].)
3042 if (tk->singleton()) {
3043 const TypeOopPtr* objtp = _gvn.type(obj)->isa_oopptr();
3044 if (objtp != NULL && objtp->klass() != NULL) {
3045 switch (C->static_subtype_check(tk->klass(), objtp->klass())) {
3046 case Compile::SSC_always_true:
3047 // If we know the type check always succeed then we don't use
3048 // the profiling data at this bytecode. Don't lose it, feed it
3049 // to the type system as a speculative type.
3050 return record_profiled_receiver_for_speculation(obj);
3051 case Compile::SSC_always_false:
3052 // It needs a null check because a null will *pass* the cast check.
3053 // A non-null value will always produce an exception.
3054 return null_assert(obj);
3055 }
3056 }
3057 }
3058
3059 ciProfileData* data = NULL;
3060 bool safe_for_replace = false;
3061 if (failure_control == NULL) { // use MDO in regular case only
3062 assert(java_bc() == Bytecodes::_aastore ||
3063 java_bc() == Bytecodes::_checkcast,
3064 "interpreter profiles type checks only for these BCs");
3065 data = method()->method_data()->bci_to_data(bci());
3066 safe_for_replace = true;
3067 }
3068
3069 // Make the merge point
3070 enum { _obj_path = 1, _null_path, PATH_LIMIT };
3071 RegionNode* region = new RegionNode(PATH_LIMIT);
3072 Node* phi = new PhiNode(region, toop);
3073 C->set_has_split_ifs(true); // Has chance for split-if optimization
3074
3075 // Use null-cast information if it is available
3076 bool speculative_not_null = false;
3077 bool never_see_null = ((failure_control == NULL) // regular case only
3078 && seems_never_null(obj, data, speculative_not_null));
3079
3080 // Null check; get casted pointer; set region slot 3
3081 Node* null_ctl = top();
3082 Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null, safe_for_replace, speculative_not_null);
3083
3084 // If not_null_obj is dead, only null-path is taken
3085 if (stopped()) { // Doing instance-of on a NULL?
3086 set_control(null_ctl);
3087 return null();
3088 }
3089 region->init_req(_null_path, null_ctl);
3090 phi ->init_req(_null_path, null()); // Set null path value
3091 if (null_ctl == top()) {
3092 // Do this eagerly, so that pattern matches like is_diamond_phi
3093 // will work even during parsing.
3094 assert(_null_path == PATH_LIMIT-1, "delete last");
3095 region->del_req(_null_path);
3096 phi ->del_req(_null_path);
3097 }
3098
3099 Node* cast_obj = NULL;
3100 if (tk->klass_is_exact()) {
3101 // The following optimization tries to statically cast the speculative type of the object
3102 // (for example obtained during profiling) to the type of the superklass and then do a
3103 // dynamic check that the type of the object is what we expect. To work correctly
3104 // for checkcast and aastore the type of superklass should be exact.
3105 const TypeOopPtr* obj_type = _gvn.type(obj)->is_oopptr();
3106 // We may not have profiling here or it may not help us. If we have
3107 // a speculative type use it to perform an exact cast.
3108 ciKlass* spec_obj_type = obj_type->speculative_type();
3109 if (spec_obj_type != NULL || data != NULL) {
3110 cast_obj = maybe_cast_profiled_receiver(not_null_obj, tk->klass(), spec_obj_type, safe_for_replace);
3111 if (cast_obj != NULL) {
3112 if (failure_control != NULL) // failure is now impossible
3113 (*failure_control) = top();
3114 // adjust the type of the phi to the exact klass:
3115 phi->raise_bottom_type(_gvn.type(cast_obj)->meet_speculative(TypePtr::NULL_PTR));
3116 }
3117 }
3118 }
3119
3120 if (cast_obj == NULL) {
3121 // Load the object's klass
3122 Node* obj_klass = load_object_klass(not_null_obj);
3123
3124 // Generate the subtype check
3125 Node* not_subtype_ctrl = gen_subtype_check( obj_klass, superklass );
3126
3127 // Plug in success path into the merge
3128 cast_obj = _gvn.transform(new CheckCastPPNode(control(), not_null_obj, toop));
3129 // Failure path ends in uncommon trap (or may be dead - failure impossible)
3130 if (failure_control == NULL) {
3131 if (not_subtype_ctrl != top()) { // If failure is possible
3132 PreserveJVMState pjvms(this);
3133 set_control(not_subtype_ctrl);
3134 builtin_throw(Deoptimization::Reason_class_check, obj_klass);
3135 }
3136 } else {
3137 (*failure_control) = not_subtype_ctrl;
3138 }
3139 }
3140
3141 region->init_req(_obj_path, control());
3142 phi ->init_req(_obj_path, cast_obj);
3143
3144 // A merge of NULL or Casted-NotNull obj
3145 Node* res = _gvn.transform(phi);
3146
3147 // Note I do NOT always 'replace_in_map(obj,result)' here.
3148 // if( tk->klass()->can_be_primary_super() )
3149 // This means that if I successfully store an Object into an array-of-String
3150 // I 'forget' that the Object is really now known to be a String. I have to
3151 // do this because we don't have true union types for interfaces - if I store
3152 // a Baz into an array-of-Interface and then tell the optimizer it's an
3153 // Interface, I forget that it's also a Baz and cannot do Baz-like field
3154 // references to it. FIX THIS WHEN UNION TYPES APPEAR!
3155 // replace_in_map( obj, res );
3156
3157 // Return final merged results
3158 set_control( _gvn.transform(region) );
3159 record_for_igvn(region);
3160
3161 return record_profiled_receiver_for_speculation(res);
3162 }
3163
3164 //------------------------------next_monitor-----------------------------------
3165 // What number should be given to the next monitor?
3166 int GraphKit::next_monitor() {
3167 int current = jvms()->monitor_depth()* C->sync_stack_slots();
3168 int next = current + C->sync_stack_slots();
3169 // Keep the toplevel high water mark current:
3170 if (C->fixed_slots() < next) C->set_fixed_slots(next);
3171 return current;
3172 }
3173
3174 //------------------------------insert_mem_bar---------------------------------
3175 // Memory barrier to avoid floating things around
3176 // The membar serves as a pinch point between both control and all memory slices.
3177 Node* GraphKit::insert_mem_bar(int opcode, Node* precedent) {
3178 MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);
3179 mb->init_req(TypeFunc::Control, control());
3180 mb->init_req(TypeFunc::Memory, reset_memory());
3181 Node* membar = _gvn.transform(mb);
3182 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3183 set_all_memory_call(membar);
3184 return membar;
3185 }
3186
3187 //-------------------------insert_mem_bar_volatile----------------------------
3188 // Memory barrier to avoid floating things around
3189 // The membar serves as a pinch point between both control and memory(alias_idx).
3190 // If you want to make a pinch point on all memory slices, do not use this
3191 // function (even with AliasIdxBot); use insert_mem_bar() instead.
3192 Node* GraphKit::insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent) {
3193 // When Parse::do_put_xxx updates a volatile field, it appends a series
3194 // of MemBarVolatile nodes, one for *each* volatile field alias category.
3195 // The first membar is on the same memory slice as the field store opcode.
3196 // This forces the membar to follow the store. (Bug 6500685 broke this.)
3197 // All the other membars (for other volatile slices, including AliasIdxBot,
3198 // which stands for all unknown volatile slices) are control-dependent
3199 // on the first membar. This prevents later volatile loads or stores
3200 // from sliding up past the just-emitted store.
3201
3202 MemBarNode* mb = MemBarNode::make(C, opcode, alias_idx, precedent);
3203 mb->set_req(TypeFunc::Control,control());
3204 if (alias_idx == Compile::AliasIdxBot) {
3205 mb->set_req(TypeFunc::Memory, merged_memory()->base_memory());
3206 } else {
3207 assert(!(opcode == Op_Initialize && alias_idx != Compile::AliasIdxRaw), "fix caller");
3208 mb->set_req(TypeFunc::Memory, memory(alias_idx));
3209 }
3210 Node* membar = _gvn.transform(mb);
3211 set_control(_gvn.transform(new ProjNode(membar, TypeFunc::Control)));
3212 if (alias_idx == Compile::AliasIdxBot) {
3213 merged_memory()->set_base_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)));
3214 } else {
3215 set_memory(_gvn.transform(new ProjNode(membar, TypeFunc::Memory)),alias_idx);
3216 }
3217 return membar;
3218 }
3219
3220 //------------------------------shared_lock------------------------------------
3221 // Emit locking code.
3222 FastLockNode* GraphKit::shared_lock(Node* obj) {
3223 // bci is either a monitorenter bc or InvocationEntryBci
3224 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3225 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3226
3227 if( !GenerateSynchronizationCode )
3228 return NULL; // Not locking things?
3229 if (stopped()) // Dead monitor?
3230 return NULL;
3231
3232 assert(dead_locals_are_killed(), "should kill locals before sync. point");
3233
3234 obj = shenandoah_write_barrier(obj);
3235
3236 // Box the stack location
3237 Node* box = _gvn.transform(new BoxLockNode(next_monitor()));
3238 Node* mem = reset_memory();
3239
3240 FastLockNode * flock = _gvn.transform(new FastLockNode(0, obj, box) )->as_FastLock();
3241 if (UseBiasedLocking && PrintPreciseBiasedLockingStatistics) {
3242 // Create the counters for this fast lock.
3243 flock->create_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3244 }
3245
3246 // Create the rtm counters for this fast lock if needed.
3247 flock->create_rtm_lock_counter(sync_jvms()); // sync_jvms used to get current bci
3248
3249 // Add monitor to debug info for the slow path. If we block inside the
3250 // slow path and de-opt, we need the monitor hanging around
3251 map()->push_monitor( flock );
3252
3253 const TypeFunc *tf = LockNode::lock_type();
3254 LockNode *lock = new LockNode(C, tf);
3255
3256 lock->init_req( TypeFunc::Control, control() );
3257 lock->init_req( TypeFunc::Memory , mem );
3258 lock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3259 lock->init_req( TypeFunc::FramePtr, frameptr() );
3260 lock->init_req( TypeFunc::ReturnAdr, top() );
3261
3262 lock->init_req(TypeFunc::Parms + 0, obj);
3263 lock->init_req(TypeFunc::Parms + 1, box);
3264 lock->init_req(TypeFunc::Parms + 2, flock);
3265 add_safepoint_edges(lock);
3266
3267 lock = _gvn.transform( lock )->as_Lock();
3268
3269 // lock has no side-effects, sets few values
3270 set_predefined_output_for_runtime_call(lock, mem, TypeRawPtr::BOTTOM);
3271
3272 insert_mem_bar(Op_MemBarAcquireLock);
3273
3274 // Add this to the worklist so that the lock can be eliminated
3275 record_for_igvn(lock);
3276
3277 #ifndef PRODUCT
3278 if (PrintLockStatistics) {
3279 // Update the counter for this lock. Don't bother using an atomic
3280 // operation since we don't require absolute accuracy.
3281 lock->create_lock_counter(map()->jvms());
3282 increment_counter(lock->counter()->addr());
3283 }
3284 #endif
3285
3286 return flock;
3287 }
3288
3289
3290 //------------------------------shared_unlock----------------------------------
3291 // Emit unlocking code.
3292 void GraphKit::shared_unlock(Node* box, Node* obj) {
3293 // bci is either a monitorenter bc or InvocationEntryBci
3294 // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces
3295 assert(SynchronizationEntryBCI == InvocationEntryBci, "");
3296
3297 if( !GenerateSynchronizationCode )
3298 return;
3299 if (stopped()) { // Dead monitor?
3300 map()->pop_monitor(); // Kill monitor from debug info
3301 return;
3302 }
3303
3304 // Memory barrier to avoid floating things down past the locked region
3305 insert_mem_bar(Op_MemBarReleaseLock);
3306
3307 const TypeFunc *tf = OptoRuntime::complete_monitor_exit_Type();
3308 UnlockNode *unlock = new UnlockNode(C, tf);
3309 #ifdef ASSERT
3310 unlock->set_dbg_jvms(sync_jvms());
3311 #endif
3312 uint raw_idx = Compile::AliasIdxRaw;
3313 unlock->init_req( TypeFunc::Control, control() );
3314 unlock->init_req( TypeFunc::Memory , memory(raw_idx) );
3315 unlock->init_req( TypeFunc::I_O , top() ) ; // does no i/o
3316 unlock->init_req( TypeFunc::FramePtr, frameptr() );
3317 unlock->init_req( TypeFunc::ReturnAdr, top() );
3318
3319 unlock->init_req(TypeFunc::Parms + 0, obj);
3320 unlock->init_req(TypeFunc::Parms + 1, box);
3321 unlock = _gvn.transform(unlock)->as_Unlock();
3322
3323 Node* mem = reset_memory();
3324
3325 // unlock has no side-effects, sets few values
3326 set_predefined_output_for_runtime_call(unlock, mem, TypeRawPtr::BOTTOM);
3327
3328 // Kill monitor from debug info
3329 map()->pop_monitor( );
3330 }
3331
3332 //-------------------------------get_layout_helper-----------------------------
3333 // If the given klass is a constant or known to be an array,
3334 // fetch the constant layout helper value into constant_value
3335 // and return (Node*)NULL. Otherwise, load the non-constant
3336 // layout helper value, and return the node which represents it.
3337 // This two-faced routine is useful because allocation sites
3338 // almost always feature constant types.
3339 Node* GraphKit::get_layout_helper(Node* klass_node, jint& constant_value) {
3340 const TypeKlassPtr* inst_klass = _gvn.type(klass_node)->isa_klassptr();
3341 if (!StressReflectiveCode && inst_klass != NULL) {
3342 ciKlass* klass = inst_klass->klass();
3343 bool xklass = inst_klass->klass_is_exact();
3344 if (xklass || klass->is_array_klass()) {
3345 jint lhelper = klass->layout_helper();
3346 if (lhelper != Klass::_lh_neutral_value) {
3347 constant_value = lhelper;
3348 return (Node*) NULL;
3349 }
3350 }
3351 }
3352 constant_value = Klass::_lh_neutral_value; // put in a known value
3353 Node* lhp = basic_plus_adr(klass_node, klass_node, in_bytes(Klass::layout_helper_offset()));
3354 return make_load(NULL, lhp, TypeInt::INT, T_INT, MemNode::unordered);
3355 }
3356
3357 // We just put in an allocate/initialize with a big raw-memory effect.
3358 // Hook selected additional alias categories on the initialization.
3359 static void hook_memory_on_init(GraphKit& kit, int alias_idx,
3360 MergeMemNode* init_in_merge,
3361 Node* init_out_raw) {
3362 DEBUG_ONLY(Node* init_in_raw = init_in_merge->base_memory());
3363 assert(init_in_merge->memory_at(alias_idx) == init_in_raw, "");
3364
3365 Node* prevmem = kit.memory(alias_idx);
3366 init_in_merge->set_memory_at(alias_idx, prevmem);
3367 kit.set_memory(init_out_raw, alias_idx);
3368 }
3369
3370 //---------------------------set_output_for_allocation-------------------------
3371 Node* GraphKit::set_output_for_allocation(AllocateNode* alloc,
3372 const TypeOopPtr* oop_type,
3373 bool deoptimize_on_exception) {
3374 int rawidx = Compile::AliasIdxRaw;
3375 alloc->set_req( TypeFunc::FramePtr, frameptr() );
3376 add_safepoint_edges(alloc);
3377 Node* allocx = _gvn.transform(alloc);
3378 set_control( _gvn.transform(new ProjNode(allocx, TypeFunc::Control) ) );
3379 // create memory projection for i_o
3380 set_memory ( _gvn.transform( new ProjNode(allocx, TypeFunc::Memory, true) ), rawidx );
3381 make_slow_call_ex(allocx, env()->Throwable_klass(), true, deoptimize_on_exception);
3382
3383 // create a memory projection as for the normal control path
3384 Node* malloc = _gvn.transform(new ProjNode(allocx, TypeFunc::Memory));
3385 set_memory(malloc, rawidx);
3386
3387 // a normal slow-call doesn't change i_o, but an allocation does
3388 // we create a separate i_o projection for the normal control path
3389 set_i_o(_gvn.transform( new ProjNode(allocx, TypeFunc::I_O, false) ) );
3390 Node* rawoop = _gvn.transform( new ProjNode(allocx, TypeFunc::Parms) );
3391
3392 // put in an initialization barrier
3393 InitializeNode* init = insert_mem_bar_volatile(Op_Initialize, rawidx,
3394 rawoop)->as_Initialize();
3395 assert(alloc->initialization() == init, "2-way macro link must work");
3396 assert(init ->allocation() == alloc, "2-way macro link must work");
3397 {
3398 // Extract memory strands which may participate in the new object's
3399 // initialization, and source them from the new InitializeNode.
3400 // This will allow us to observe initializations when they occur,
3401 // and link them properly (as a group) to the InitializeNode.
3402 assert(init->in(InitializeNode::Memory) == malloc, "");
3403 MergeMemNode* minit_in = MergeMemNode::make(malloc);
3404 init->set_req(InitializeNode::Memory, minit_in);
3405 record_for_igvn(minit_in); // fold it up later, if possible
3406 Node* minit_out = memory(rawidx);
3407 assert(minit_out->is_Proj() && minit_out->in(0) == init, "");
3408 if (oop_type->isa_aryptr()) {
3409 const TypePtr* telemref = oop_type->add_offset(Type::OffsetBot);
3410 int elemidx = C->get_alias_index(telemref);
3411 hook_memory_on_init(*this, elemidx, minit_in, minit_out);
3412 } else if (oop_type->isa_instptr()) {
3413 ciInstanceKlass* ik = oop_type->klass()->as_instance_klass();
3414 for (int i = 0, len = ik->nof_nonstatic_fields(); i < len; i++) {
3415 ciField* field = ik->nonstatic_field_at(i);
3416 if (field->offset() >= TrackedInitializationLimit * HeapWordSize)
3417 continue; // do not bother to track really large numbers of fields
3418 // Find (or create) the alias category for this field:
3419 int fieldidx = C->alias_type(field)->index();
3420 hook_memory_on_init(*this, fieldidx, minit_in, minit_out);
3421 }
3422 }
3423 }
3424
3425 // Cast raw oop to the real thing...
3426 Node* javaoop = new CheckCastPPNode(control(), rawoop, oop_type);
3427 javaoop = _gvn.transform(javaoop);
3428 C->set_recent_alloc(control(), javaoop);
3429 assert(just_allocated_object(control()) == javaoop, "just allocated");
3430
3431 #ifdef ASSERT
3432 { // Verify that the AllocateNode::Ideal_allocation recognizers work:
3433 assert(AllocateNode::Ideal_allocation(rawoop, &_gvn) == alloc,
3434 "Ideal_allocation works");
3435 assert(AllocateNode::Ideal_allocation(javaoop, &_gvn) == alloc,
3436 "Ideal_allocation works");
3437 if (alloc->is_AllocateArray()) {
3438 assert(AllocateArrayNode::Ideal_array_allocation(rawoop, &_gvn) == alloc->as_AllocateArray(),
3439 "Ideal_allocation works");
3440 assert(AllocateArrayNode::Ideal_array_allocation(javaoop, &_gvn) == alloc->as_AllocateArray(),
3441 "Ideal_allocation works");
3442 } else {
3443 assert(alloc->in(AllocateNode::ALength)->is_top(), "no length, please");
3444 }
3445 }
3446 #endif //ASSERT
3447
3448 return javaoop;
3449 }
3450
3451 //---------------------------new_instance--------------------------------------
3452 // This routine takes a klass_node which may be constant (for a static type)
3453 // or may be non-constant (for reflective code). It will work equally well
3454 // for either, and the graph will fold nicely if the optimizer later reduces
3455 // the type to a constant.
3456 // The optional arguments are for specialized use by intrinsics:
3457 // - If 'extra_slow_test' if not null is an extra condition for the slow-path.
3458 // - If 'return_size_val', report the the total object size to the caller.
3459 // - deoptimize_on_exception controls how Java exceptions are handled (rethrow vs deoptimize)
3460 Node* GraphKit::new_instance(Node* klass_node,
3461 Node* extra_slow_test,
3462 Node* *return_size_val,
3463 bool deoptimize_on_exception) {
3464 // Compute size in doublewords
3465 // The size is always an integral number of doublewords, represented
3466 // as a positive bytewise size stored in the klass's layout_helper.
3467 // The layout_helper also encodes (in a low bit) the need for a slow path.
3468 jint layout_con = Klass::_lh_neutral_value;
3469 Node* layout_val = get_layout_helper(klass_node, layout_con);
3470 int layout_is_con = (layout_val == NULL);
3471
3472 if (extra_slow_test == NULL) extra_slow_test = intcon(0);
3473 // Generate the initial go-slow test. It's either ALWAYS (return a
3474 // Node for 1) or NEVER (return a NULL) or perhaps (in the reflective
3475 // case) a computed value derived from the layout_helper.
3476 Node* initial_slow_test = NULL;
3477 if (layout_is_con) {
3478 assert(!StressReflectiveCode, "stress mode does not use these paths");
3479 bool must_go_slow = Klass::layout_helper_needs_slow_path(layout_con);
3480 initial_slow_test = must_go_slow ? intcon(1) : extra_slow_test;
3481 } else { // reflective case
3482 // This reflective path is used by Unsafe.allocateInstance.
3483 // (It may be stress-tested by specifying StressReflectiveCode.)
3484 // Basically, we want to get into the VM is there's an illegal argument.
3485 Node* bit = intcon(Klass::_lh_instance_slow_path_bit);
3486 initial_slow_test = _gvn.transform( new AndINode(layout_val, bit) );
3487 if (extra_slow_test != intcon(0)) {
3488 initial_slow_test = _gvn.transform( new OrINode(initial_slow_test, extra_slow_test) );
3489 }
3490 // (Macro-expander will further convert this to a Bool, if necessary.)
3491 }
3492
3493 // Find the size in bytes. This is easy; it's the layout_helper.
3494 // The size value must be valid even if the slow path is taken.
3495 Node* size = NULL;
3496 if (layout_is_con) {
3497 size = MakeConX(Klass::layout_helper_size_in_bytes(layout_con));
3498 } else { // reflective case
3499 // This reflective path is used by clone and Unsafe.allocateInstance.
3500 size = ConvI2X(layout_val);
3501
3502 // Clear the low bits to extract layout_helper_size_in_bytes:
3503 assert((int)Klass::_lh_instance_slow_path_bit < BytesPerLong, "clear bit");
3504 Node* mask = MakeConX(~ (intptr_t)right_n_bits(LogBytesPerLong));
3505 size = _gvn.transform( new AndXNode(size, mask) );
3506 }
3507 if (return_size_val != NULL) {
3508 (*return_size_val) = size;
3509 }
3510
3511 // This is a precise notnull oop of the klass.
3512 // (Actually, it need not be precise if this is a reflective allocation.)
3513 // It's what we cast the result to.
3514 const TypeKlassPtr* tklass = _gvn.type(klass_node)->isa_klassptr();
3515 if (!tklass) tklass = TypeKlassPtr::OBJECT;
3516 const TypeOopPtr* oop_type = tklass->as_instance_type();
3517
3518 // Now generate allocation code
3519
3520 // The entire memory state is needed for slow path of the allocation
3521 // since GC and deoptimization can happened.
3522 Node *mem = reset_memory();
3523 set_all_memory(mem); // Create new memory state
3524
3525 AllocateNode* alloc = new AllocateNode(C, AllocateNode::alloc_type(Type::TOP),
3526 control(), mem, i_o(),
3527 size, klass_node,
3528 initial_slow_test);
3529
3530 return set_output_for_allocation(alloc, oop_type, deoptimize_on_exception);
3531 }
3532
3533 //-------------------------------new_array-------------------------------------
3534 // helper for both newarray and anewarray
3535 // The 'length' parameter is (obviously) the length of the array.
3536 // See comments on new_instance for the meaning of the other arguments.
3537 Node* GraphKit::new_array(Node* klass_node, // array klass (maybe variable)
3538 Node* length, // number of array elements
3539 int nargs, // number of arguments to push back for uncommon trap
3540 Node* *return_size_val,
3541 bool deoptimize_on_exception) {
3542 jint layout_con = Klass::_lh_neutral_value;
3543 Node* layout_val = get_layout_helper(klass_node, layout_con);
3544 int layout_is_con = (layout_val == NULL);
3545
3546 if (!layout_is_con && !StressReflectiveCode &&
3547 !too_many_traps(Deoptimization::Reason_class_check)) {
3548 // This is a reflective array creation site.
3549 // Optimistically assume that it is a subtype of Object[],
3550 // so that we can fold up all the address arithmetic.
3551 layout_con = Klass::array_layout_helper(T_OBJECT);
3552 Node* cmp_lh = _gvn.transform( new CmpINode(layout_val, intcon(layout_con)) );
3553 Node* bol_lh = _gvn.transform( new BoolNode(cmp_lh, BoolTest::eq) );
3554 { BuildCutout unless(this, bol_lh, PROB_MAX);
3555 inc_sp(nargs);
3556 uncommon_trap(Deoptimization::Reason_class_check,
3557 Deoptimization::Action_maybe_recompile);
3558 }
3559 layout_val = NULL;
3560 layout_is_con = true;
3561 }
3562
3563 // Generate the initial go-slow test. Make sure we do not overflow
3564 // if length is huge (near 2Gig) or negative! We do not need
3565 // exact double-words here, just a close approximation of needed
3566 // double-words. We can't add any offset or rounding bits, lest we
3567 // take a size -1 of bytes and make it positive. Use an unsigned
3568 // compare, so negative sizes look hugely positive.
3569 int fast_size_limit = FastAllocateSizeLimit;
3570 if (layout_is_con) {
3571 assert(!StressReflectiveCode, "stress mode does not use these paths");
3572 // Increase the size limit if we have exact knowledge of array type.
3573 int log2_esize = Klass::layout_helper_log2_element_size(layout_con);
3574 fast_size_limit <<= (LogBytesPerLong - log2_esize);
3575 }
3576
3577 Node* initial_slow_cmp = _gvn.transform( new CmpUNode( length, intcon( fast_size_limit ) ) );
3578 Node* initial_slow_test = _gvn.transform( new BoolNode( initial_slow_cmp, BoolTest::gt ) );
3579
3580 // --- Size Computation ---
3581 // array_size = round_to_heap(array_header + (length << elem_shift));
3582 // where round_to_heap(x) == align_to(x, MinObjAlignmentInBytes)
3583 // and align_to(x, y) == ((x + y-1) & ~(y-1))
3584 // The rounding mask is strength-reduced, if possible.
3585 int round_mask = MinObjAlignmentInBytes - 1;
3586 Node* header_size = NULL;
3587 int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
3588 // (T_BYTE has the weakest alignment and size restrictions...)
3589 if (layout_is_con) {
3590 int hsize = Klass::layout_helper_header_size(layout_con);
3591 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3592 BasicType etype = Klass::layout_helper_element_type(layout_con);
3593 if ((round_mask & ~right_n_bits(eshift)) == 0)
3594 round_mask = 0; // strength-reduce it if it goes away completely
3595 assert((hsize & right_n_bits(eshift)) == 0, "hsize is pre-rounded");
3596 assert(header_size_min <= hsize, "generic minimum is smallest");
3597 header_size_min = hsize;
3598 header_size = intcon(hsize + round_mask);
3599 } else {
3600 Node* hss = intcon(Klass::_lh_header_size_shift);
3601 Node* hsm = intcon(Klass::_lh_header_size_mask);
3602 Node* hsize = _gvn.transform( new URShiftINode(layout_val, hss) );
3603 hsize = _gvn.transform( new AndINode(hsize, hsm) );
3604 Node* mask = intcon(round_mask);
3605 header_size = _gvn.transform( new AddINode(hsize, mask) );
3606 }
3607
3608 Node* elem_shift = NULL;
3609 if (layout_is_con) {
3610 int eshift = Klass::layout_helper_log2_element_size(layout_con);
3611 if (eshift != 0)
3612 elem_shift = intcon(eshift);
3613 } else {
3614 // There is no need to mask or shift this value.
3615 // The semantics of LShiftINode include an implicit mask to 0x1F.
3616 assert(Klass::_lh_log2_element_size_shift == 0, "use shift in place");
3617 elem_shift = layout_val;
3618 }
3619
3620 // Transition to native address size for all offset calculations:
3621 Node* lengthx = ConvI2X(length);
3622 Node* headerx = ConvI2X(header_size);
3623 #ifdef _LP64
3624 { const TypeInt* tilen = _gvn.find_int_type(length);
3625 if (tilen != NULL && tilen->_lo < 0) {
3626 // Add a manual constraint to a positive range. Cf. array_element_address.
3627 jint size_max = fast_size_limit;
3628 if (size_max > tilen->_hi) size_max = tilen->_hi;
3629 const TypeInt* tlcon = TypeInt::make(0, size_max, Type::WidenMin);
3630
3631 // Only do a narrow I2L conversion if the range check passed.
3632 IfNode* iff = new IfNode(control(), initial_slow_test, PROB_MIN, COUNT_UNKNOWN);
3633 _gvn.transform(iff);
3634 RegionNode* region = new RegionNode(3);
3635 _gvn.set_type(region, Type::CONTROL);
3636 lengthx = new PhiNode(region, TypeLong::LONG);
3637 _gvn.set_type(lengthx, TypeLong::LONG);
3638
3639 // Range check passed. Use ConvI2L node with narrow type.
3640 Node* passed = IfFalse(iff);
3641 region->init_req(1, passed);
3642 // Make I2L conversion control dependent to prevent it from
3643 // floating above the range check during loop optimizations.
3644 lengthx->init_req(1, C->constrained_convI2L(&_gvn, length, tlcon, passed));
3645
3646 // Range check failed. Use ConvI2L with wide type because length may be invalid.
3647 region->init_req(2, IfTrue(iff));
3648 lengthx->init_req(2, ConvI2X(length));
3649
3650 set_control(region);
3651 record_for_igvn(region);
3652 record_for_igvn(lengthx);
3653 }
3654 }
3655 #endif
3656
3657 // Combine header size (plus rounding) and body size. Then round down.
3658 // This computation cannot overflow, because it is used only in two
3659 // places, one where the length is sharply limited, and the other
3660 // after a successful allocation.
3661 Node* abody = lengthx;
3662 if (elem_shift != NULL)
3663 abody = _gvn.transform( new LShiftXNode(lengthx, elem_shift) );
3664 Node* size = _gvn.transform( new AddXNode(headerx, abody) );
3665 if (round_mask != 0) {
3666 Node* mask = MakeConX(~round_mask);
3667 size = _gvn.transform( new AndXNode(size, mask) );
3668 }
3669 // else if round_mask == 0, the size computation is self-rounding
3670
3671 if (return_size_val != NULL) {
3672 // This is the size
3673 (*return_size_val) = size;
3674 }
3675
3676 // Now generate allocation code
3677
3678 // The entire memory state is needed for slow path of the allocation
3679 // since GC and deoptimization can happened.
3680 Node *mem = reset_memory();
3681 set_all_memory(mem); // Create new memory state
3682
3683 if (initial_slow_test->is_Bool()) {
3684 // Hide it behind a CMoveI, or else PhaseIdealLoop::split_up will get sick.
3685 initial_slow_test = initial_slow_test->as_Bool()->as_int_value(&_gvn);
3686 }
3687
3688 // Create the AllocateArrayNode and its result projections
3689 AllocateArrayNode* alloc
3690 = new AllocateArrayNode(C, AllocateArrayNode::alloc_type(TypeInt::INT),
3691 control(), mem, i_o(),
3692 size, klass_node,
3693 initial_slow_test,
3694 length);
3695
3696 // Cast to correct type. Note that the klass_node may be constant or not,
3697 // and in the latter case the actual array type will be inexact also.
3698 // (This happens via a non-constant argument to inline_native_newArray.)
3699 // In any case, the value of klass_node provides the desired array type.
3700 const TypeInt* length_type = _gvn.find_int_type(length);
3701 const TypeOopPtr* ary_type = _gvn.type(klass_node)->is_klassptr()->as_instance_type();
3702 if (ary_type->isa_aryptr() && length_type != NULL) {
3703 // Try to get a better type than POS for the size
3704 ary_type = ary_type->is_aryptr()->cast_to_size(length_type);
3705 }
3706
3707 Node* javaoop = set_output_for_allocation(alloc, ary_type, deoptimize_on_exception);
3708
3709 // Cast length on remaining path to be as narrow as possible
3710 if (map()->find_edge(length) >= 0) {
3711 Node* ccast = alloc->make_ideal_length(ary_type, &_gvn);
3712 if (ccast != length) {
3713 _gvn.set_type_bottom(ccast);
3714 record_for_igvn(ccast);
3715 replace_in_map(length, ccast);
3716 }
3717 }
3718
3719 return javaoop;
3720 }
3721
3722 // The following "Ideal_foo" functions are placed here because they recognize
3723 // the graph shapes created by the functions immediately above.
3724
3725 //---------------------------Ideal_allocation----------------------------------
3726 // Given an oop pointer or raw pointer, see if it feeds from an AllocateNode.
3727 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase) {
3728 if (ptr == NULL) { // reduce dumb test in callers
3729 return NULL;
3730 }
3731
3732 // Attempt to see through Shenandoah barriers.
3733 ptr = ShenandoahBarrierNode::skip_through_barrier(ptr);
3734
3735 if (ptr->is_CheckCastPP()) { // strip only one raw-to-oop cast
3736 ptr = ptr->in(1);
3737 if (ptr == NULL) return NULL;
3738 }
3739 // Return NULL for allocations with several casts:
3740 // j.l.reflect.Array.newInstance(jobject, jint)
3741 // Object.clone()
3742 // to keep more precise type from last cast.
3743 if (ptr->is_Proj()) {
3744 Node* allo = ptr->in(0);
3745 if (allo != NULL && allo->is_Allocate()) {
3746 return allo->as_Allocate();
3747 }
3748 }
3749 // Report failure to match.
3750 return NULL;
3751 }
3752
3753 // Fancy version which also strips off an offset (and reports it to caller).
3754 AllocateNode* AllocateNode::Ideal_allocation(Node* ptr, PhaseTransform* phase,
3755 intptr_t& offset) {
3756 Node* base = AddPNode::Ideal_base_and_offset(ptr, phase, offset);
3757 if (base == NULL) return NULL;
3758 return Ideal_allocation(base, phase);
3759 }
3760
3761 // Trace Initialize <- Proj[Parm] <- Allocate
3762 AllocateNode* InitializeNode::allocation() {
3763 Node* rawoop = in(InitializeNode::RawAddress);
3764 if (rawoop->is_Proj()) {
3765 Node* alloc = rawoop->in(0);
3766 if (alloc->is_Allocate()) {
3767 return alloc->as_Allocate();
3768 }
3769 }
3770 return NULL;
3771 }
3772
3773 // Trace Allocate -> Proj[Parm] -> Initialize
3774 InitializeNode* AllocateNode::initialization() {
3775 ProjNode* rawoop = proj_out(AllocateNode::RawAddress);
3776 if (rawoop == NULL) return NULL;
3777 for (DUIterator_Fast imax, i = rawoop->fast_outs(imax); i < imax; i++) {
3778 Node* init = rawoop->fast_out(i);
3779 if (init->is_Initialize()) {
3780 assert(init->as_Initialize()->allocation() == this, "2-way link");
3781 return init->as_Initialize();
3782 }
3783 }
3784 return NULL;
3785 }
3786
3787 //----------------------------- loop predicates ---------------------------
3788
3789 //------------------------------add_predicate_impl----------------------------
3790 void GraphKit::add_predicate_impl(Deoptimization::DeoptReason reason, int nargs) {
3791 // Too many traps seen?
3792 if (too_many_traps(reason)) {
3793 #ifdef ASSERT
3794 if (TraceLoopPredicate) {
3795 int tc = C->trap_count(reason);
3796 tty->print("too many traps=%s tcount=%d in ",
3797 Deoptimization::trap_reason_name(reason), tc);
3798 method()->print(); // which method has too many predicate traps
3799 tty->cr();
3800 }
3801 #endif
3802 // We cannot afford to take more traps here,
3803 // do not generate predicate.
3804 return;
3805 }
3806
3807 Node *cont = _gvn.intcon(1);
3808 Node* opq = _gvn.transform(new Opaque1Node(C, cont));
3809 Node *bol = _gvn.transform(new Conv2BNode(opq));
3810 IfNode* iff = create_and_map_if(control(), bol, PROB_MAX, COUNT_UNKNOWN);
3811 Node* iffalse = _gvn.transform(new IfFalseNode(iff));
3812 C->add_predicate_opaq(opq);
3813 {
3814 PreserveJVMState pjvms(this);
3815 set_control(iffalse);
3816 inc_sp(nargs);
3817 uncommon_trap(reason, Deoptimization::Action_maybe_recompile);
3818 }
3819 Node* iftrue = _gvn.transform(new IfTrueNode(iff));
3820 set_control(iftrue);
3821 }
3822
3823 //------------------------------add_predicate---------------------------------
3824 void GraphKit::add_predicate(int nargs) {
3825 if (UseLoopPredicate) {
3826 add_predicate_impl(Deoptimization::Reason_predicate, nargs);
3827 }
3828 // loop's limit check predicate should be near the loop.
3829 add_predicate_impl(Deoptimization::Reason_loop_limit_check, nargs);
3830 }
3831
3832 //----------------------------- store barriers ----------------------------
3833 #define __ ideal.
3834
3835 void GraphKit::sync_kit(IdealKit& ideal) {
3836 set_all_memory(__ merged_memory());
3837 set_i_o(__ i_o());
3838 set_control(__ ctrl());
3839 }
3840
3841 void GraphKit::final_sync(IdealKit& ideal) {
3842 // Final sync IdealKit and graphKit.
3843 sync_kit(ideal);
3844 }
3845
3846 Node* GraphKit::byte_map_base_node() {
3847 // Get base of card map
3848 CardTableModRefBS* ct =
3849 barrier_set_cast<CardTableModRefBS>(Universe::heap()->barrier_set());
3850 assert(sizeof(*ct->byte_map_base) == sizeof(jbyte), "adjust users of this code");
3851 if (ct->byte_map_base != NULL) {
3852 return makecon(TypeRawPtr::make((address)ct->byte_map_base));
3853 } else {
3854 return null();
3855 }
3856 }
3857
3858 // vanilla/CMS post barrier
3859 // Insert a write-barrier store. This is to let generational GC work; we have
3860 // to flag all oop-stores before the next GC point.
3861 void GraphKit::write_barrier_post(Node* oop_store,
3862 Node* obj,
3863 Node* adr,
3864 uint adr_idx,
3865 Node* val,
3866 bool use_precise) {
3867 // No store check needed if we're storing a NULL or an old object
3868 // (latter case is probably a string constant). The concurrent
3869 // mark sweep garbage collector, however, needs to have all nonNull
3870 // oop updates flagged via card-marks.
3871 if (val != NULL && val->is_Con()) {
3872 // must be either an oop or NULL
3873 const Type* t = val->bottom_type();
3874 if (t == TypePtr::NULL_PTR || t == Type::TOP)
3875 // stores of null never (?) need barriers
3876 return;
3877 }
3878
3879 if (use_ReduceInitialCardMarks()
3880 && obj == just_allocated_object(control())) {
3881 // We can skip marks on a freshly-allocated object in Eden.
3882 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
3883 // That routine informs GC to take appropriate compensating steps,
3884 // upon a slow-path allocation, so as to make this card-mark
3885 // elision safe.
3886 return;
3887 }
3888
3889 if (!use_precise) {
3890 // All card marks for a (non-array) instance are in one place:
3891 adr = obj;
3892 }
3893 // (Else it's an array (or unknown), and we want more precise card marks.)
3894 assert(adr != NULL, "");
3895
3896 IdealKit ideal(this, true);
3897
3898 // Convert the pointer to an int prior to doing math on it
3899 Node* cast = __ CastPX(__ ctrl(), adr);
3900
3901 // Divide by card size
3902 assert(Universe::heap()->barrier_set()->is_a(BarrierSet::CardTableModRef),
3903 "Only one we handle so far.");
3904 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
3905
3906 // Combine card table base and card offset
3907 Node* card_adr = __ AddP(__ top(), byte_map_base_node(), card_offset );
3908
3909 // Get the alias_index for raw card-mark memory
3910 int adr_type = Compile::AliasIdxRaw;
3911 Node* zero = __ ConI(0); // Dirty card value
3912 BasicType bt = T_BYTE;
3913
3914 if (UseConcMarkSweepGC && UseCondCardMark) {
3915 insert_mem_bar(Op_MemBarVolatile); // StoreLoad barrier
3916 __ sync_kit(this);
3917 }
3918
3919 if (UseCondCardMark) {
3920 // The classic GC reference write barrier is typically implemented
3921 // as a store into the global card mark table. Unfortunately
3922 // unconditional stores can result in false sharing and excessive
3923 // coherence traffic as well as false transactional aborts.
3924 // UseCondCardMark enables MP "polite" conditional card mark
3925 // stores. In theory we could relax the load from ctrl() to
3926 // no_ctrl, but that doesn't buy much latitude.
3927 Node* card_val = __ load( __ ctrl(), card_adr, TypeInt::BYTE, bt, adr_type);
3928 __ if_then(card_val, BoolTest::ne, zero);
3929 }
3930
3931 // Smash zero into card
3932 if( !UseConcMarkSweepGC ) {
3933 __ store(__ ctrl(), card_adr, zero, bt, adr_type, MemNode::unordered);
3934 } else {
3935 // Specialized path for CM store barrier
3936 __ storeCM(__ ctrl(), card_adr, zero, oop_store, adr_idx, bt, adr_type);
3937 }
3938
3939 if (UseCondCardMark) {
3940 __ end_if();
3941 }
3942
3943 // Final sync IdealKit and GraphKit.
3944 final_sync(ideal);
3945 }
3946 /*
3947 * Determine if the G1 pre-barrier can be removed. The pre-barrier is
3948 * required by SATB to make sure all objects live at the start of the
3949 * marking are kept alive, all reference updates need to any previous
3950 * reference stored before writing.
3951 *
3952 * If the previous value is NULL there is no need to save the old value.
3953 * References that are NULL are filtered during runtime by the barrier
3954 * code to avoid unnecessary queuing.
3955 *
3956 * However in the case of newly allocated objects it might be possible to
3957 * prove that the reference about to be overwritten is NULL during compile
3958 * time and avoid adding the barrier code completely.
3959 *
3960 * The compiler needs to determine that the object in which a field is about
3961 * to be written is newly allocated, and that no prior store to the same field
3962 * has happened since the allocation.
3963 *
3964 * Returns true if the pre-barrier can be removed
3965 */
3966 bool GraphKit::g1_can_remove_pre_barrier(PhaseTransform* phase, Node* adr,
3967 BasicType bt, uint adr_idx) {
3968 intptr_t offset = 0;
3969 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
3970 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
3971
3972 if (offset == Type::OffsetBot) {
3973 return false; // cannot unalias unless there are precise offsets
3974 }
3975
3976 if (alloc == NULL) {
3977 return false; // No allocation found
3978 }
3979
3980 intptr_t size_in_bytes = type2aelembytes(bt);
3981
3982 Node* mem = memory(adr_idx); // start searching here...
3983
3984 for (int cnt = 0; cnt < 50; cnt++) {
3985
3986 if (mem->is_Store()) {
3987
3988 Node* st_adr = mem->in(MemNode::Address);
3989 intptr_t st_offset = 0;
3990 Node* st_base = AddPNode::Ideal_base_and_offset(st_adr, phase, st_offset);
3991
3992 if (st_base == NULL) {
3993 break; // inscrutable pointer
3994 }
3995
3996 // Break we have found a store with same base and offset as ours so break
3997 if (st_base == base && st_offset == offset) {
3998 break;
3999 }
4000
4001 if (st_offset != offset && st_offset != Type::OffsetBot) {
4002 const int MAX_STORE = BytesPerLong;
4003 if (st_offset >= offset + size_in_bytes ||
4004 st_offset <= offset - MAX_STORE ||
4005 st_offset <= offset - mem->as_Store()->memory_size()) {
4006 // Success: The offsets are provably independent.
4007 // (You may ask, why not just test st_offset != offset and be done?
4008 // The answer is that stores of different sizes can co-exist
4009 // in the same sequence of RawMem effects. We sometimes initialize
4010 // a whole 'tile' of array elements with a single jint or jlong.)
4011 mem = mem->in(MemNode::Memory);
4012 continue; // advance through independent store memory
4013 }
4014 }
4015
4016 if (st_base != base
4017 && MemNode::detect_ptr_independence(base, alloc, st_base,
4018 AllocateNode::Ideal_allocation(st_base, phase),
4019 phase)) {
4020 // Success: The bases are provably independent.
4021 mem = mem->in(MemNode::Memory);
4022 continue; // advance through independent store memory
4023 }
4024 } else if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
4025
4026 InitializeNode* st_init = mem->in(0)->as_Initialize();
4027 AllocateNode* st_alloc = st_init->allocation();
4028
4029 // Make sure that we are looking at the same allocation site.
4030 // The alloc variable is guaranteed to not be null here from earlier check.
4031 if (alloc == st_alloc) {
4032 // Check that the initialization is storing NULL so that no previous store
4033 // has been moved up and directly write a reference
4034 Node* captured_store = st_init->find_captured_store(offset,
4035 type2aelembytes(T_OBJECT),
4036 phase);
4037 if (captured_store == NULL || captured_store == st_init->zero_memory()) {
4038 return true;
4039 }
4040 }
4041 }
4042
4043 // Unless there is an explicit 'continue', we must bail out here,
4044 // because 'mem' is an inscrutable memory state (e.g., a call).
4045 break;
4046 }
4047
4048 return false;
4049 }
4050
4051 static void g1_write_barrier_pre_helper(const GraphKit& kit, Node* adr) {
4052 if (UseShenandoahGC && ShenandoahSATBBarrier && adr != NULL) {
4053 Node* c = kit.control();
4054 Node* call = c->in(1)->in(1)->in(1)->in(0);
4055 assert(call->is_g1_wb_pre_call(), "g1_wb_pre call expected");
4056 call->add_req(adr);
4057 }
4058 }
4059
4060 // G1 pre/post barriers
4061 void GraphKit::g1_write_barrier_pre(bool do_load,
4062 Node* obj,
4063 Node* adr,
4064 uint alias_idx,
4065 Node* val,
4066 const TypeOopPtr* val_type,
4067 Node* pre_val,
4068 BasicType bt) {
4069
4070 // Some sanity checks
4071 // Note: val is unused in this routine.
4072
4073 if (do_load) {
4074 // We need to generate the load of the previous value
4075 assert(obj != NULL, "must have a base");
4076 assert(adr != NULL, "where are loading from?");
4077 assert(pre_val == NULL, "loaded already?");
4078 assert(val_type != NULL, "need a type");
4079
4080 if (use_ReduceInitialCardMarks()
4081 && g1_can_remove_pre_barrier(&_gvn, adr, bt, alias_idx)) {
4082 return;
4083 }
4084
4085 } else {
4086 // In this case both val_type and alias_idx are unused.
4087 assert(pre_val != NULL, "must be loaded already");
4088 // Nothing to be done if pre_val is null.
4089 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return;
4090 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
4091 }
4092 assert(bt == T_OBJECT, "or we shouldn't be here");
4093
4094 IdealKit ideal(this, true);
4095
4096 Node* tls = __ thread(); // ThreadLocalStorage
4097
4098 Node* no_ctrl = NULL;
4099 Node* no_base = __ top();
4100 Node* zero = __ ConI(0);
4101 Node* zeroX = __ ConX(0);
4102
4103 float likely = PROB_LIKELY(0.999);
4104 float unlikely = PROB_UNLIKELY(0.999);
4105
4106 BasicType active_type = in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE;
4107 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 || in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "flag width");
4108
4109 // Offsets into the thread
4110 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 648
4111 SATBMarkQueue::byte_offset_of_active());
4112 const int index_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 656
4113 SATBMarkQueue::byte_offset_of_index());
4114 const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
4115 SATBMarkQueue::byte_offset_of_buf());
4116
4117 // Now the actual pointers into the thread
4118 Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
4119 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4120 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4121
4122 // Now some of the values
4123 Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
4124
4125 // if (!marking)
4126 __ if_then(marking, BoolTest::ne, zero, unlikely); {
4127 BasicType index_bt = TypeX_X->basic_type();
4128 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 SATBMarkQueue::_index with wrong size.");
4129 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
4130
4131 if (do_load) {
4132 // load original value
4133 // alias_idx correct??
4134 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
4135 }
4136
4137 // if (pre_val != NULL)
4138 __ if_then(pre_val, BoolTest::ne, null()); {
4139 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4140
4141 // is the queue for this thread full?
4142 __ if_then(index, BoolTest::ne, zeroX, likely); {
4143
4144 // decrement the index
4145 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4146
4147 // Now get the buffer location we will log the previous value into and store it
4148 Node *log_addr = __ AddP(no_base, buffer, next_index);
4149 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
4150 // update the index
4151 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
4152
4153 } __ else_(); {
4154
4155 // logging buffer is full, call the runtime
4156 const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
4157 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
4158 } __ end_if(); // (!index)
4159 } __ end_if(); // (pre_val != NULL)
4160 } __ end_if(); // (!marking)
4161
4162 // Final sync IdealKit and GraphKit.
4163 final_sync(ideal);
4164 g1_write_barrier_pre_helper(*this, adr);
4165 }
4166
4167 Node* GraphKit::shenandoah_write_barrier_pre(bool do_load,
4168 Node* obj,
4169 Node* adr,
4170 uint alias_idx,
4171 Node* val,
4172 const TypeOopPtr* val_type,
4173 Node* pre_val,
4174 BasicType bt) {
4175
4176 // Some sanity checks
4177 // Note: val is unused in this routine.
4178
4179 if (!ShenandoahSATBBarrier) {
4180 if (val != NULL) {
4181 shenandoah_update_matrix(adr, val);
4182 }
4183 return val;
4184 }
4185
4186 if (val == NULL) {
4187 g1_write_barrier_pre(do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
4188 return NULL;
4189 }
4190
4191 if (! ShenandoahReduceStoreValBarrier) {
4192 val = shenandoah_storeval_barrier(val);
4193 shenandoah_update_matrix(adr, val);
4194 g1_write_barrier_pre(do_load, obj, adr, alias_idx, val, val_type, pre_val, bt);
4195 return val;
4196 }
4197
4198 if (do_load) {
4199 // We need to generate the load of the previous value
4200 assert(obj != NULL, "must have a base");
4201 assert(adr != NULL, "where are loading from?");
4202 assert(pre_val == NULL, "loaded already?");
4203 assert(val_type != NULL, "need a type");
4204
4205 if (use_ReduceInitialCardMarks()
4206 && g1_can_remove_pre_barrier(&_gvn, adr, bt, alias_idx)) {
4207 return shenandoah_storeval_barrier(val);
4208 }
4209
4210 } else {
4211 // In this case both val_type and alias_idx are unused.
4212 assert(pre_val != NULL, "must be loaded already");
4213 // Nothing to be done if pre_val is null.
4214 if (pre_val->bottom_type() == TypePtr::NULL_PTR) return val;
4215 assert(pre_val->bottom_type()->basic_type() == T_OBJECT, "or we shouldn't be here");
4216 }
4217 assert(bt == T_OBJECT, "or we shouldn't be here");
4218
4219 IdealKit ideal(this, true, true);
4220 IdealVariable ival(ideal);
4221 __ declarations_done();
4222 __ set(ival, val);
4223 Node* tls = __ thread(); // ThreadLocalStorage
4224
4225 Node* no_ctrl = NULL;
4226 Node* no_base = __ top();
4227 Node* zero = __ ConI(0);
4228 Node* zeroX = __ ConX(0);
4229
4230 float likely = PROB_LIKELY(0.999);
4231 float unlikely = PROB_UNLIKELY(0.999);
4232
4233 BasicType active_type = in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 ? T_INT : T_BYTE;
4234 assert(in_bytes(SATBMarkQueue::byte_width_of_active()) == 4 || in_bytes(SATBMarkQueue::byte_width_of_active()) == 1, "flag width");
4235
4236 // Offsets into the thread
4237 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 648
4238 SATBMarkQueue::byte_offset_of_active());
4239 const int index_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 656
4240 SATBMarkQueue::byte_offset_of_index());
4241 const int buffer_offset = in_bytes(JavaThread::satb_mark_queue_offset() + // 652
4242 SATBMarkQueue::byte_offset_of_buf());
4243
4244 // Now the actual pointers into the thread
4245 Node* marking_adr = __ AddP(no_base, tls, __ ConX(marking_offset));
4246 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4247 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4248
4249 // Now some of the values
4250 Node* marking = __ load(__ ctrl(), marking_adr, TypeInt::INT, active_type, Compile::AliasIdxRaw);
4251
4252 // if (!marking)
4253 __ if_then(marking, BoolTest::ne, zero, unlikely); {
4254
4255 Node* storeval = ideal.value(ival);
4256 sync_kit(ideal);
4257 storeval = shenandoah_storeval_barrier(storeval);
4258 __ sync_kit(this);
4259 __ set(ival, storeval);
4260
4261 BasicType index_bt = TypeX_X->basic_type();
4262 assert(sizeof(size_t) == type2aelembytes(index_bt), "Loading G1 SATBMarkQueue::_index with wrong size.");
4263 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, index_bt, Compile::AliasIdxRaw);
4264
4265 if (do_load) {
4266 // load original value
4267 // alias_idx correct??
4268 pre_val = __ load(__ ctrl(), adr, val_type, bt, alias_idx);
4269 }
4270
4271 // if (pre_val != NULL)
4272 __ if_then(pre_val, BoolTest::ne, null()); {
4273 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4274
4275 // is the queue for this thread full?
4276 __ if_then(index, BoolTest::ne, zeroX, likely); {
4277
4278 // decrement the index
4279 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4280
4281 // Now get the buffer location we will log the previous value into and store it
4282 Node *log_addr = __ AddP(no_base, buffer, next_index);
4283 __ store(__ ctrl(), log_addr, pre_val, T_OBJECT, Compile::AliasIdxRaw, MemNode::unordered);
4284 // update the index
4285 __ store(__ ctrl(), index_adr, next_index, index_bt, Compile::AliasIdxRaw, MemNode::unordered);
4286
4287 } __ else_(); {
4288
4289 // logging buffer is full, call the runtime
4290 const TypeFunc *tf = OptoRuntime::g1_wb_pre_Type();
4291 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), "g1_wb_pre", pre_val, tls);
4292 } __ end_if(); // (!index)
4293 } __ end_if(); // (pre_val != NULL)
4294 } __ end_if(); // (!marking)
4295 Node* new_val = __ value(ival);
4296 // IdealKit generates a Phi with very conservative type, and even
4297 // turns array types into TypeInstPtr (see type.cpp, _const_basic_type[T_ARRAY]).
4298 // We're forcing the result to be the original type.
4299 if (new_val != val) {
4300 const Type* t = _gvn.type(val);
4301 if (new_val->isa_Type()) {
4302 new_val->as_Type()->set_type(t);
4303 }
4304 _gvn.set_type(new_val, t);
4305 }
4306 val = new_val;
4307 __ dead(ival);
4308 // Final sync IdealKit and GraphKit.
4309 final_sync(ideal);
4310 g1_write_barrier_pre_helper(*this, adr);
4311 return val;
4312 }
4313
4314 void GraphKit::shenandoah_update_matrix(Node* adr, Node* val) {
4315 if (!UseShenandoahMatrix) {
4316 return;
4317 }
4318
4319 assert(val != NULL, "checked before");
4320 if (adr == NULL) {
4321 return; // Nothing to do
4322 }
4323 assert(adr != NULL, "must not happen");
4324 if (val->bottom_type()->higher_equal(TypePtr::NULL_PTR)) {
4325 // Nothing to do.
4326 return;
4327 }
4328
4329 ShenandoahConnectionMatrix* matrix = ShenandoahHeap::heap()->connection_matrix();
4330
4331 enum { _set_path = 1, _already_set_path, _val_null_path, PATH_LIMIT };
4332 RegionNode* region = new RegionNode(PATH_LIMIT);
4333 Node* prev_mem = memory(Compile::AliasIdxRaw);
4334 Node* memphi = PhiNode::make(region, prev_mem, Type::MEMORY, TypeRawPtr::BOTTOM);
4335 Node* null_ctrl = top();
4336 Node* not_null_val = null_check_oop(val, &null_ctrl);
4337
4338 // Null path: nothing to do.
4339 region->init_req(_val_null_path, null_ctrl);
4340 memphi->init_req(_val_null_path, prev_mem);
4341
4342 // Not null path. Update the matrix.
4343
4344 // This uses a fast calculation for the matrix address. For a description,
4345 // see src/share/vm/gc/shenandoah/shenandoahConnectionMatrix.inline.hpp,
4346 // ShenandoahConnectionMatrix::compute_address(const void* from, const void* to).
4347 address heap_base = ShenandoahHeap::heap()->base();
4348 jint stride = matrix->stride_jint();
4349 jint rs = ShenandoahHeapRegion::region_size_bytes_shift_jint();
4350
4351 guarantee(stride < ShenandoahHeapRegion::region_size_bytes_jint(), "sanity");
4352 guarantee(is_aligned(heap_base, ShenandoahHeapRegion::region_size_bytes()), "sanity");
4353
4354 Node* magic_con = MakeConX((jlong) matrix->matrix_addr() - ((jlong) heap_base >> rs) * (stride + 1));
4355
4356 // Compute addr part
4357 Node* adr_idx = _gvn.transform(new CastP2XNode(control(), adr));
4358 adr_idx = _gvn.transform(new URShiftXNode(adr_idx, intcon(rs)));
4359
4360 // Compute new_val part
4361 Node* val_idx = _gvn.transform(new CastP2XNode(control(), not_null_val));
4362 val_idx = _gvn.transform(new URShiftXNode(val_idx, intcon(rs)));
4363 val_idx = _gvn.transform(new MulXNode(val_idx, MakeConX(stride)));
4364
4365 // Add everything up
4366 adr_idx = _gvn.transform(new AddXNode(adr_idx, val_idx));
4367 adr_idx = _gvn.transform(new CastX2PNode(adr_idx));
4368 Node* matrix_adr = _gvn.transform(new AddPNode(top(), adr_idx, magic_con));
4369
4370 // Load current value
4371 const TypePtr* adr_type = TypeRawPtr::BOTTOM;
4372 Node* current = _gvn.transform(LoadNode::make(_gvn, control(), memory(Compile::AliasIdxRaw),
4373 matrix_adr, adr_type, TypeInt::INT, T_BYTE, MemNode::unordered));
4374
4375 // Check if already set
4376 Node* cmp_set = _gvn.transform(new CmpINode(current, intcon(0)));
4377 Node* cmp_set_bool = _gvn.transform(new BoolNode(cmp_set, BoolTest::eq));
4378 IfNode* cmp_iff = create_and_map_if(control(), cmp_set_bool, PROB_MIN, COUNT_UNKNOWN);
4379
4380 Node* if_not_set = _gvn.transform(new IfTrueNode(cmp_iff));
4381 Node* if_set = _gvn.transform(new IfFalseNode(cmp_iff));
4382
4383 // Already set, exit
4384 set_control(if_set);
4385 region->init_req(_already_set_path, control());
4386 memphi->init_req(_already_set_path, prev_mem);
4387
4388 // Not set: do the store, and finish up
4389 set_control(if_not_set);
4390 Node* store = _gvn.transform(StoreNode::make(_gvn, control(), memory(Compile::AliasIdxRaw),
4391 matrix_adr, adr_type, intcon(1), T_BYTE, MemNode::unordered));
4392 region->init_req(_set_path, control());
4393 memphi->init_req(_set_path, store);
4394
4395 // Merge control flows and memory.
4396 set_control(_gvn.transform(region));
4397 record_for_igvn(region);
4398 set_memory(_gvn.transform(memphi), Compile::AliasIdxRaw);
4399 }
4400
4401 /*
4402 * G1 similar to any GC with a Young Generation requires a way to keep track of
4403 * references from Old Generation to Young Generation to make sure all live
4404 * objects are found. G1 also requires to keep track of object references
4405 * between different regions to enable evacuation of old regions, which is done
4406 * as part of mixed collections. References are tracked in remembered sets and
4407 * is continuously updated as reference are written to with the help of the
4408 * post-barrier.
4409 *
4410 * To reduce the number of updates to the remembered set the post-barrier
4411 * filters updates to fields in objects located in the Young Generation,
4412 * the same region as the reference, when the NULL is being written or
4413 * if the card is already marked as dirty by an earlier write.
4414 *
4415 * Under certain circumstances it is possible to avoid generating the
4416 * post-barrier completely if it is possible during compile time to prove
4417 * the object is newly allocated and that no safepoint exists between the
4418 * allocation and the store.
4419 *
4420 * In the case of slow allocation the allocation code must handle the barrier
4421 * as part of the allocation in the case the allocated object is not located
4422 * in the nursery, this would happen for humongous objects. This is similar to
4423 * how CMS is required to handle this case, see the comments for the method
4424 * CollectedHeap::new_store_pre_barrier and OptoRuntime::new_store_pre_barrier.
4425 * A deferred card mark is required for these objects and handled in the above
4426 * mentioned methods.
4427 *
4428 * Returns true if the post barrier can be removed
4429 */
4430 bool GraphKit::g1_can_remove_post_barrier(PhaseTransform* phase, Node* store,
4431 Node* adr) {
4432 intptr_t offset = 0;
4433 Node* base = AddPNode::Ideal_base_and_offset(adr, phase, offset);
4434 AllocateNode* alloc = AllocateNode::Ideal_allocation(base, phase);
4435
4436 if (offset == Type::OffsetBot) {
4437 return false; // cannot unalias unless there are precise offsets
4438 }
4439
4440 if (alloc == NULL) {
4441 return false; // No allocation found
4442 }
4443
4444 // Start search from Store node
4445 Node* mem = store->in(MemNode::Control);
4446 if (mem->is_Proj() && mem->in(0)->is_Initialize()) {
4447
4448 InitializeNode* st_init = mem->in(0)->as_Initialize();
4449 AllocateNode* st_alloc = st_init->allocation();
4450
4451 // Make sure we are looking at the same allocation
4452 if (alloc == st_alloc) {
4453 return true;
4454 }
4455 }
4456
4457 return false;
4458 }
4459
4460 //
4461 // Update the card table and add card address to the queue
4462 //
4463 void GraphKit::g1_mark_card(IdealKit& ideal,
4464 Node* card_adr,
4465 Node* oop_store,
4466 uint oop_alias_idx,
4467 Node* index,
4468 Node* index_adr,
4469 Node* buffer,
4470 const TypeFunc* tf) {
4471
4472 Node* zero = __ ConI(0);
4473 Node* zeroX = __ ConX(0);
4474 Node* no_base = __ top();
4475 BasicType card_bt = T_BYTE;
4476 // Smash zero into card. MUST BE ORDERED WRT TO STORE
4477 __ storeCM(__ ctrl(), card_adr, zero, oop_store, oop_alias_idx, card_bt, Compile::AliasIdxRaw);
4478
4479 // Now do the queue work
4480 __ if_then(index, BoolTest::ne, zeroX); {
4481
4482 Node* next_index = _gvn.transform(new SubXNode(index, __ ConX(sizeof(intptr_t))));
4483 Node* log_addr = __ AddP(no_base, buffer, next_index);
4484
4485 // Order, see storeCM.
4486 __ store(__ ctrl(), log_addr, card_adr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);
4487 __ store(__ ctrl(), index_adr, next_index, TypeX_X->basic_type(), Compile::AliasIdxRaw, MemNode::unordered);
4488
4489 } __ else_(); {
4490 __ make_leaf_call(tf, CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), "g1_wb_post", card_adr, __ thread());
4491 } __ end_if();
4492
4493 }
4494
4495 void GraphKit::g1_write_barrier_post(Node* oop_store,
4496 Node* obj,
4497 Node* adr,
4498 uint alias_idx,
4499 Node* val,
4500 BasicType bt,
4501 bool use_precise) {
4502 // If we are writing a NULL then we need no post barrier
4503
4504 if (val != NULL && val->is_Con() && val->bottom_type() == TypePtr::NULL_PTR) {
4505 // Must be NULL
4506 const Type* t = val->bottom_type();
4507 assert(t == Type::TOP || t == TypePtr::NULL_PTR, "must be NULL");
4508 // No post barrier if writing NULLx
4509 return;
4510 }
4511
4512 if (use_ReduceInitialCardMarks() && obj == just_allocated_object(control())) {
4513 // We can skip marks on a freshly-allocated object in Eden.
4514 // Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
4515 // That routine informs GC to take appropriate compensating steps,
4516 // upon a slow-path allocation, so as to make this card-mark
4517 // elision safe.
4518 return;
4519 }
4520
4521 if (use_ReduceInitialCardMarks()
4522 && g1_can_remove_post_barrier(&_gvn, oop_store, adr)) {
4523 return;
4524 }
4525
4526 if (!use_precise) {
4527 // All card marks for a (non-array) instance are in one place:
4528 adr = obj;
4529 }
4530 // (Else it's an array (or unknown), and we want more precise card marks.)
4531 assert(adr != NULL, "");
4532
4533 IdealKit ideal(this, true);
4534
4535 Node* tls = __ thread(); // ThreadLocalStorage
4536
4537 Node* no_base = __ top();
4538 float likely = PROB_LIKELY(0.999);
4539 float unlikely = PROB_UNLIKELY(0.999);
4540 Node* young_card = __ ConI((jint)G1SATBCardTableModRefBS::g1_young_card_val());
4541 Node* dirty_card = __ ConI((jint)CardTableModRefBS::dirty_card_val());
4542 Node* zeroX = __ ConX(0);
4543
4544 // Get the alias_index for raw card-mark memory
4545 const TypePtr* card_type = TypeRawPtr::BOTTOM;
4546
4547 const TypeFunc *tf = OptoRuntime::g1_wb_post_Type();
4548
4549 // Offsets into the thread
4550 const int index_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4551 DirtyCardQueue::byte_offset_of_index());
4552 const int buffer_offset = in_bytes(JavaThread::dirty_card_queue_offset() +
4553 DirtyCardQueue::byte_offset_of_buf());
4554
4555 // Pointers into the thread
4556
4557 Node* buffer_adr = __ AddP(no_base, tls, __ ConX(buffer_offset));
4558 Node* index_adr = __ AddP(no_base, tls, __ ConX(index_offset));
4559
4560 // Now some values
4561 // Use ctrl to avoid hoisting these values past a safepoint, which could
4562 // potentially reset these fields in the JavaThread.
4563 Node* index = __ load(__ ctrl(), index_adr, TypeX_X, TypeX_X->basic_type(), Compile::AliasIdxRaw);
4564 Node* buffer = __ load(__ ctrl(), buffer_adr, TypeRawPtr::NOTNULL, T_ADDRESS, Compile::AliasIdxRaw);
4565
4566 // Convert the store obj pointer to an int prior to doing math on it
4567 // Must use ctrl to prevent "integerized oop" existing across safepoint
4568 Node* cast = __ CastPX(__ ctrl(), adr);
4569
4570 // Divide pointer by card size
4571 Node* card_offset = __ URShiftX( cast, __ ConI(CardTableModRefBS::card_shift) );
4572
4573 // Combine card table base and card offset
4574 Node* card_adr = __ AddP(no_base, byte_map_base_node(), card_offset );
4575
4576 // If we know the value being stored does it cross regions?
4577
4578 if (val != NULL) {
4579 // Does the store cause us to cross regions?
4580
4581 // Should be able to do an unsigned compare of region_size instead of
4582 // and extra shift. Do we have an unsigned compare??
4583 // Node* region_size = __ ConI(1 << HeapRegion::LogOfHRGrainBytes);
4584 Node* xor_res = __ URShiftX ( __ XorX( cast, __ CastPX(__ ctrl(), val)), __ ConI(HeapRegion::LogOfHRGrainBytes));
4585
4586 // if (xor_res == 0) same region so skip
4587 __ if_then(xor_res, BoolTest::ne, zeroX); {
4588
4589 // No barrier if we are storing a NULL
4590 __ if_then(val, BoolTest::ne, null(), unlikely); {
4591
4592 // Ok must mark the card if not already dirty
4593
4594 // load the original value of the card
4595 Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4596
4597 __ if_then(card_val, BoolTest::ne, young_card); {
4598 sync_kit(ideal);
4599 // Use Op_MemBarVolatile to achieve the effect of a StoreLoad barrier.
4600 insert_mem_bar(Op_MemBarVolatile, oop_store);
4601 __ sync_kit(this);
4602
4603 Node* card_val_reload = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4604 __ if_then(card_val_reload, BoolTest::ne, dirty_card); {
4605 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4606 } __ end_if();
4607 } __ end_if();
4608 } __ end_if();
4609 } __ end_if();
4610 } else {
4611 // The Object.clone() intrinsic uses this path if !ReduceInitialCardMarks.
4612 // We don't need a barrier here if the destination is a newly allocated object
4613 // in Eden. Otherwise, GC verification breaks because we assume that cards in Eden
4614 // are set to 'g1_young_gen' (see G1SATBCardTableModRefBS::verify_g1_young_region()).
4615 assert(!use_ReduceInitialCardMarks(), "can only happen with card marking");
4616 Node* card_val = __ load(__ ctrl(), card_adr, TypeInt::INT, T_BYTE, Compile::AliasIdxRaw);
4617 __ if_then(card_val, BoolTest::ne, young_card); {
4618 g1_mark_card(ideal, card_adr, oop_store, alias_idx, index, index_adr, buffer, tf);
4619 } __ end_if();
4620 }
4621
4622 // Final sync IdealKit and GraphKit.
4623 final_sync(ideal);
4624 }
4625 #undef __
4626
4627
4628 Node* GraphKit::load_String_length(Node* ctrl, Node* str) {
4629 Node* len = load_array_length(load_String_value(ctrl, str));
4630 Node* coder = load_String_coder(ctrl, str);
4631 // Divide length by 2 if coder is UTF16
4632 return _gvn.transform(new RShiftINode(len, coder));
4633 }
4634
4635 Node* GraphKit::load_String_value(Node* ctrl, Node* str) {
4636 int value_offset = java_lang_String::value_offset_in_bytes();
4637 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4638 false, NULL, 0);
4639 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4640 const TypeAryPtr* value_type = TypeAryPtr::make(TypePtr::NotNull,
4641 TypeAry::make(TypeInt::BYTE, TypeInt::POS),
4642 ciTypeArrayKlass::make(T_BYTE), true, 0);
4643 int value_field_idx = C->get_alias_index(value_field_type);
4644
4645 if (! ShenandoahOptimizeFinals) {
4646 str = shenandoah_read_barrier(str);
4647 }
4648
4649 Node* load = make_load(ctrl, basic_plus_adr(str, str, value_offset),
4650 value_type, T_OBJECT, value_field_idx, MemNode::unordered);
4651 // String.value field is known to be @Stable.
4652 if (UseImplicitStableValues) {
4653 load = cast_array_to_stable(load, value_type);
4654 }
4655 return load;
4656 }
4657
4658 Node* GraphKit::load_String_coder(Node* ctrl, Node* str) {
4659 if (!CompactStrings) {
4660 return intcon(java_lang_String::CODER_UTF16);
4661 }
4662 int coder_offset = java_lang_String::coder_offset_in_bytes();
4663 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4664 false, NULL, 0);
4665 const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
4666 int coder_field_idx = C->get_alias_index(coder_field_type);
4667
4668 if (! ShenandoahOptimizeFinals) {
4669 str = shenandoah_read_barrier(str);
4670 }
4671
4672 return make_load(ctrl, basic_plus_adr(str, str, coder_offset),
4673 TypeInt::BYTE, T_BYTE, coder_field_idx, MemNode::unordered);
4674 }
4675
4676 void GraphKit::store_String_value(Node* ctrl, Node* str, Node* value) {
4677 int value_offset = java_lang_String::value_offset_in_bytes();
4678 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4679 false, NULL, 0);
4680 const TypePtr* value_field_type = string_type->add_offset(value_offset);
4681
4682 str = shenandoah_write_barrier(str);
4683
4684 store_oop_to_object(control(), str, basic_plus_adr(str, value_offset), value_field_type,
4685 value, TypeAryPtr::BYTES, T_OBJECT, MemNode::unordered);
4686 }
4687
4688 void GraphKit::store_String_coder(Node* ctrl, Node* str, Node* value) {
4689 int coder_offset = java_lang_String::coder_offset_in_bytes();
4690 const TypeInstPtr* string_type = TypeInstPtr::make(TypePtr::NotNull, C->env()->String_klass(),
4691 false, NULL, 0);
4692
4693 str = shenandoah_write_barrier(str);
4694
4695 const TypePtr* coder_field_type = string_type->add_offset(coder_offset);
4696 int coder_field_idx = C->get_alias_index(coder_field_type);
4697 store_to_memory(control(), basic_plus_adr(str, coder_offset),
4698 value, T_BYTE, coder_field_idx, MemNode::unordered);
4699 }
4700
4701 // Capture src and dst memory state with a MergeMemNode
4702 Node* GraphKit::capture_memory(const TypePtr* src_type, const TypePtr* dst_type) {
4703 if (src_type == dst_type) {
4704 // Types are equal, we don't need a MergeMemNode
4705 return memory(src_type);
4706 }
4707 MergeMemNode* merge = MergeMemNode::make(map()->memory());
4708 record_for_igvn(merge); // fold it up later, if possible
4709 int src_idx = C->get_alias_index(src_type);
4710 int dst_idx = C->get_alias_index(dst_type);
4711 merge->set_memory_at(src_idx, memory(src_idx));
4712 merge->set_memory_at(dst_idx, memory(dst_idx));
4713 return merge;
4714 }
4715
4716 Node* GraphKit::compress_string(Node* src, const TypeAryPtr* src_type, Node* dst, Node* count) {
4717 assert(Matcher::match_rule_supported(Op_StrCompressedCopy), "Intrinsic not supported");
4718 assert(src_type == TypeAryPtr::BYTES || src_type == TypeAryPtr::CHARS, "invalid source type");
4719 // If input and output memory types differ, capture both states to preserve
4720 // the dependency between preceding and subsequent loads/stores.
4721 // For example, the following program:
4722 // StoreB
4723 // compress_string
4724 // LoadB
4725 // has this memory graph (use->def):
4726 // LoadB -> compress_string -> CharMem
4727 // ... -> StoreB -> ByteMem
4728 // The intrinsic hides the dependency between LoadB and StoreB, causing
4729 // the load to read from memory not containing the result of the StoreB.
4730 // The correct memory graph should look like this:
4731 // LoadB -> compress_string -> MergeMem(CharMem, StoreB(ByteMem))
4732 Node* mem = capture_memory(src_type, TypeAryPtr::BYTES);
4733 StrCompressedCopyNode* str = new StrCompressedCopyNode(control(), mem, src, dst, count);
4734 Node* res_mem = _gvn.transform(new SCMemProjNode(str));
4735 set_memory(res_mem, TypeAryPtr::BYTES);
4736 return str;
4737 }
4738
4739 void GraphKit::inflate_string(Node* src, Node* dst, const TypeAryPtr* dst_type, Node* count) {
4740 assert(Matcher::match_rule_supported(Op_StrInflatedCopy), "Intrinsic not supported");
4741 assert(dst_type == TypeAryPtr::BYTES || dst_type == TypeAryPtr::CHARS, "invalid dest type");
4742 // Capture src and dst memory (see comment in 'compress_string').
4743 Node* mem = capture_memory(TypeAryPtr::BYTES, dst_type);
4744 StrInflatedCopyNode* str = new StrInflatedCopyNode(control(), mem, src, dst, count);
4745 set_memory(_gvn.transform(str), dst_type);
4746 }
4747
4748 void GraphKit::inflate_string_slow(Node* src, Node* dst, Node* start, Node* count) {
4749
4750 src = shenandoah_read_barrier(src);
4751 dst = shenandoah_write_barrier(dst);
4752
4753 /**
4754 * int i_char = start;
4755 * for (int i_byte = 0; i_byte < count; i_byte++) {
4756 * dst[i_char++] = (char)(src[i_byte] & 0xff);
4757 * }
4758 */
4759 add_predicate();
4760 RegionNode* head = new RegionNode(3);
4761 head->init_req(1, control());
4762 gvn().set_type(head, Type::CONTROL);
4763 record_for_igvn(head);
4764
4765 Node* i_byte = new PhiNode(head, TypeInt::INT);
4766 i_byte->init_req(1, intcon(0));
4767 gvn().set_type(i_byte, TypeInt::INT);
4768 record_for_igvn(i_byte);
4769
4770 Node* i_char = new PhiNode(head, TypeInt::INT);
4771 i_char->init_req(1, start);
4772 gvn().set_type(i_char, TypeInt::INT);
4773 record_for_igvn(i_char);
4774
4775 Node* mem = PhiNode::make(head, memory(TypeAryPtr::BYTES), Type::MEMORY, TypeAryPtr::BYTES);
4776 gvn().set_type(mem, Type::MEMORY);
4777 record_for_igvn(mem);
4778 set_control(head);
4779 set_memory(mem, TypeAryPtr::BYTES);
4780 Node* ch = load_array_element(control(), src, i_byte, TypeAryPtr::BYTES);
4781 Node* st = store_to_memory(control(), array_element_address(dst, i_char, T_BYTE),
4782 AndI(ch, intcon(0xff)), T_CHAR, TypeAryPtr::BYTES, MemNode::unordered,
4783 false, false, true /* mismatched */);
4784
4785 IfNode* iff = create_and_map_if(head, Bool(CmpI(i_byte, count), BoolTest::lt), PROB_FAIR, COUNT_UNKNOWN);
4786 head->init_req(2, IfTrue(iff));
4787 mem->init_req(2, st);
4788 i_byte->init_req(2, AddI(i_byte, intcon(1)));
4789 i_char->init_req(2, AddI(i_char, intcon(2)));
4790
4791 set_control(IfFalse(iff));
4792 set_memory(st, TypeAryPtr::BYTES);
4793 }
4794
4795 Node* GraphKit::make_constant_from_field(ciField* field, Node* obj) {
4796 if (!field->is_constant()) {
4797 return NULL; // Field not marked as constant.
4798 }
4799 ciInstance* holder = NULL;
4800 if (!field->is_static()) {
4801 ciObject* const_oop = obj->bottom_type()->is_oopptr()->const_oop();
4802 if (const_oop != NULL && const_oop->is_instance()) {
4803 holder = const_oop->as_instance();
4804 }
4805 }
4806 const Type* con_type = Type::make_constant_from_field(field, holder, field->layout_type(),
4807 /*is_unsigned_load=*/false);
4808 if (con_type != NULL) {
4809 return makecon(con_type);
4810 }
4811 return NULL;
4812 }
4813
4814 Node* GraphKit::cast_array_to_stable(Node* ary, const TypeAryPtr* ary_type) {
4815 // Reify the property as a CastPP node in Ideal graph to comply with monotonicity
4816 // assumption of CCP analysis.
4817 return _gvn.transform(new CastPPNode(ary, ary_type->cast_to_stable(true)));
4818 }
4819
4820 Node* GraphKit::shenandoah_read_barrier(Node* obj) {
4821 if (UseShenandoahGC && ShenandoahReadBarrier) {
4822 return shenandoah_read_barrier_impl(obj, false, true, true);
4823 } else {
4824 return obj;
4825 }
4826 }
4827
4828 Node* GraphKit::shenandoah_storeval_barrier(Node* obj) {
4829 if (UseShenandoahGC && ShenandoahStoreValBarrier) {
4830 return shenandoah_read_barrier_impl(obj, true, false, false);
4831 } else {
4832 return obj;
4833 }
4834 }
4835
4836 Node* GraphKit::shenandoah_read_barrier_acmp(Node* obj) {
4837 return shenandoah_read_barrier_impl(obj, true, true, false);
4838 }
4839
4840 Node* GraphKit::shenandoah_read_barrier_impl(Node* obj, bool use_ctrl, bool use_mem, bool allow_fromspace) {
4841
4842 const Type* obj_type = obj->bottom_type();
4843 if (obj_type->higher_equal(TypePtr::NULL_PTR)) {
4844 return obj;
4845 }
4846 const TypePtr* adr_type = ShenandoahBarrierNode::brooks_pointer_type(obj_type);
4847 Node* mem = use_mem ? memory(adr_type) : immutable_memory();
4848
4849 if (! ShenandoahBarrierNode::needs_barrier(&_gvn, NULL, obj, mem, allow_fromspace)) {
4850 // We know it is null, no barrier needed.
4851 return obj;
4852 }
4853
4854
4855 if (obj_type->meet(TypePtr::NULL_PTR) == obj_type->remove_speculative()) {
4856
4857 // We don't know if it's null or not. Need null-check.
4858 enum { _not_null_path = 1, _null_path, PATH_LIMIT };
4859 RegionNode* region = new RegionNode(PATH_LIMIT);
4860 Node* phi = new PhiNode(region, obj_type);
4861 Node* null_ctrl = top();
4862 Node* not_null_obj = null_check_oop(obj, &null_ctrl);
4863
4864 region->init_req(_null_path, null_ctrl);
4865 phi ->init_req(_null_path, zerocon(T_OBJECT));
4866
4867 Node* ctrl = use_ctrl ? control() : NULL;
4868 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, not_null_obj, allow_fromspace);
4869 Node* n = _gvn.transform(rb);
4870
4871 region->init_req(_not_null_path, control());
4872 phi ->init_req(_not_null_path, n);
4873
4874 set_control(_gvn.transform(region));
4875 record_for_igvn(region);
4876 return _gvn.transform(phi);
4877
4878 } else {
4879 // We know it is not null. Simple barrier is sufficient.
4880 Node* ctrl = use_ctrl ? control() : NULL;
4881 ShenandoahReadBarrierNode* rb = new ShenandoahReadBarrierNode(ctrl, mem, obj, allow_fromspace);
4882 Node* n = _gvn.transform(rb);
4883 record_for_igvn(n);
4884 return n;
4885 }
4886 }
4887
4888 static Node* shenandoah_write_barrier_helper(GraphKit& kit, Node* obj, const TypePtr* adr_type) {
4889 ShenandoahWriteBarrierNode* wb = new ShenandoahWriteBarrierNode(kit.C, kit.control(), kit.memory(adr_type), obj);
4890 Node* n = kit.gvn().transform(wb);
4891 if (n == wb) { // New barrier needs memory projection.
4892 Node* proj = kit.gvn().transform(new ShenandoahWBMemProjNode(n));
4893 kit.set_memory(proj, adr_type);
4894 }
4895
4896 return n;
4897 }
4898
4899 Node* GraphKit::shenandoah_write_barrier(Node* obj) {
4900
4901 if (UseShenandoahGC && ShenandoahWriteBarrier) {
4902
4903 if (! ShenandoahBarrierNode::needs_barrier(&_gvn, NULL, obj, NULL, true)) {
4904 return obj;
4905 }
4906 const Type* obj_type = obj->bottom_type();
4907 const TypePtr* adr_type = ShenandoahBarrierNode::brooks_pointer_type(obj_type);
4908 if (obj_type->meet(TypePtr::NULL_PTR) == obj_type->remove_speculative()) {
4909 // We don't know if it's null or not. Need null-check.
4910 enum { _not_null_path = 1, _null_path, PATH_LIMIT };
4911 RegionNode* region = new RegionNode(PATH_LIMIT);
4912 Node* phi = new PhiNode(region, obj_type);
4913 Node* memphi = PhiNode::make(region, memory(adr_type), Type::MEMORY, C->alias_type(adr_type)->adr_type());
4914
4915 Node* prev_mem = memory(adr_type);
4916 Node* null_ctrl = top();
4917 Node* not_null_obj = null_check_oop(obj, &null_ctrl);
4918
4919 region->init_req(_null_path, null_ctrl);
4920 phi ->init_req(_null_path, zerocon(T_OBJECT));
4921 memphi->init_req(_null_path, prev_mem);
4922
4923 Node* n = shenandoah_write_barrier_helper(*this, not_null_obj, adr_type);
4924
4925 region->init_req(_not_null_path, control());
4926 phi ->init_req(_not_null_path, n);
4927 memphi->init_req(_not_null_path, memory(adr_type));
4928
4929 set_control(_gvn.transform(region));
4930 record_for_igvn(region);
4931 set_memory(_gvn.transform(memphi), adr_type);
4932
4933 Node* res_val = _gvn.transform(phi);
4934 // replace_in_map(obj, res_val);
4935 return res_val;
4936 } else {
4937 // We know it is not null. Simple barrier is sufficient.
4938 Node* n = shenandoah_write_barrier_helper(*this, obj, adr_type);
4939 // replace_in_map(obj, n);
4940 record_for_igvn(n);
4941 return n;
4942 }
4943
4944 } else {
4945 return obj;
4946 }
4947 }