1 /*
2 * Copyright (c) 2012, 2018, 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 package org.graalvm.compiler.hotspot.replacements;
26
27 import static jdk.vm.ci.code.MemoryBarriers.LOAD_STORE;
28 import static jdk.vm.ci.code.MemoryBarriers.STORE_STORE;
29 import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_OPTIONVALUES;
30 import static org.graalvm.compiler.hotspot.GraalHotSpotVMConfig.INJECTED_VMCONFIG;
31 import static org.graalvm.compiler.hotspot.nodes.AcquiredCASLockNode.mark;
32 import static org.graalvm.compiler.hotspot.nodes.BeginLockScopeNode.beginLockScope;
33 import static org.graalvm.compiler.hotspot.nodes.EndLockScopeNode.endLockScope;
34 import static org.graalvm.compiler.hotspot.nodes.VMErrorNode.vmError;
35 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.DISPLACED_MARK_WORD_LOCATION;
36 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.MARK_WORD_LOCATION;
37 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_CXQ_LOCATION;
38 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_ENTRY_LIST_LOCATION;
39 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_OWNER_LOCATION;
40 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.OBJECT_MONITOR_RECURSION_LOCATION;
41 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.PROTOTYPE_MARK_WORD_LOCATION;
42 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.ageMaskInPlace;
43 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.biasedLockMaskInPlace;
44 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.biasedLockPattern;
45 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.epochMaskInPlace;
46 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.loadWordFromObject;
47 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.lockDisplacedMarkOffset;
48 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.markOffset;
49 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.monitorMask;
50 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorCxqOffset;
51 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorEntryListOffset;
52 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorOwnerOffset;
53 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.objectMonitorRecursionsOffset;
54 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.pageSize;
55 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.prototypeMarkWordOffset;
56 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.registerAsWord;
57 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.stackBias;
58 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.unlockedMask;
59 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.useBiasedLocking;
60 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.verifyOop;
61 import static org.graalvm.compiler.hotspot.replacements.HotSpotReplacementsUtil.wordSize;
62 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.ProfileMonitors;
63 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.SimpleFastInflatedLocking;
64 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.TraceMonitorsMethodFilter;
65 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.TraceMonitorsTypeFilter;
66 import static org.graalvm.compiler.hotspot.replacements.HotspotSnippetsOptions.VerifyBalancedMonitors;
67 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.FAST_PATH_PROBABILITY;
68 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.FREQUENT_PROBABILITY;
69 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_FREQUENT_PROBABILITY;
70 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.NOT_LIKELY_PROBABILITY;
71 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.SLOW_PATH_PROBABILITY;
72 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.VERY_FAST_PATH_PROBABILITY;
73 import static org.graalvm.compiler.nodes.extended.BranchProbabilityNode.probability;
74 import static org.graalvm.compiler.nodes.extended.MembarNode.memoryBarrier;
75 import static org.graalvm.compiler.replacements.SnippetTemplate.DEFAULT_REPLACER;
76 import static jdk.internal.vm.compiler.word.WordFactory.unsigned;
77 import static jdk.internal.vm.compiler.word.WordFactory.zero;
78
79 import java.util.List;
80
81 import org.graalvm.compiler.api.replacements.Fold;
82 import org.graalvm.compiler.api.replacements.Snippet;
83 import org.graalvm.compiler.api.replacements.Snippet.ConstantParameter;
84 import org.graalvm.compiler.bytecode.Bytecode;
85 import org.graalvm.compiler.bytecode.ResolvedJavaMethodBytecode;
86 import org.graalvm.compiler.core.common.spi.ForeignCallDescriptor;
87 import org.graalvm.compiler.core.common.type.ObjectStamp;
88 import org.graalvm.compiler.core.common.type.StampFactory;
89 import org.graalvm.compiler.core.common.type.StampPair;
90 import org.graalvm.compiler.debug.DebugHandlersFactory;
91 import org.graalvm.compiler.graph.Node.ConstantNodeParameter;
92 import org.graalvm.compiler.graph.Node.NodeIntrinsic;
93 import org.graalvm.compiler.graph.iterators.NodeIterable;
94 import org.graalvm.compiler.hotspot.GraalHotSpotVMConfig;
95 import org.graalvm.compiler.hotspot.meta.HotSpotProviders;
96 import org.graalvm.compiler.hotspot.meta.HotSpotRegistersProvider;
97 import org.graalvm.compiler.hotspot.nodes.CurrentLockNode;
98 import org.graalvm.compiler.hotspot.nodes.FastAcquireBiasedLockNode;
99 import org.graalvm.compiler.hotspot.nodes.MonitorCounterNode;
100 import org.graalvm.compiler.hotspot.word.KlassPointer;
101 import org.graalvm.compiler.nodes.BreakpointNode;
102 import org.graalvm.compiler.nodes.CallTargetNode.InvokeKind;
103 import org.graalvm.compiler.nodes.ConstantNode;
104 import org.graalvm.compiler.nodes.DeoptimizeNode;
105 import org.graalvm.compiler.nodes.FrameState;
106 import org.graalvm.compiler.nodes.InvokeNode;
107 import org.graalvm.compiler.nodes.NamedLocationIdentity;
108 import org.graalvm.compiler.nodes.NodeView;
109 import org.graalvm.compiler.nodes.ReturnNode;
110 import org.graalvm.compiler.nodes.StructuredGraph;
111 import org.graalvm.compiler.nodes.ValueNode;
112 import org.graalvm.compiler.nodes.debug.DynamicCounterNode;
113 import org.graalvm.compiler.nodes.extended.ForeignCallNode;
114 import org.graalvm.compiler.nodes.extended.MembarNode;
115 import org.graalvm.compiler.nodes.java.MethodCallTargetNode;
116 import org.graalvm.compiler.nodes.java.MonitorExitNode;
117 import org.graalvm.compiler.nodes.java.RawMonitorEnterNode;
118 import org.graalvm.compiler.nodes.spi.LoweringTool;
119 import org.graalvm.compiler.nodes.type.StampTool;
120 import org.graalvm.compiler.options.OptionValues;
121 import org.graalvm.compiler.phases.common.inlining.InliningUtil;
122 import org.graalvm.compiler.replacements.Log;
123 import org.graalvm.compiler.replacements.SnippetCounter;
124 import org.graalvm.compiler.replacements.SnippetTemplate.AbstractTemplates;
125 import org.graalvm.compiler.replacements.SnippetTemplate.Arguments;
126 import org.graalvm.compiler.replacements.SnippetTemplate.SnippetInfo;
127 import org.graalvm.compiler.replacements.Snippets;
128 import org.graalvm.compiler.word.Word;
129 import jdk.internal.vm.compiler.word.LocationIdentity;
130 import jdk.internal.vm.compiler.word.Pointer;
131 import jdk.internal.vm.compiler.word.WordBase;
132 import jdk.internal.vm.compiler.word.WordFactory;
133
134 import jdk.vm.ci.code.BytecodeFrame;
135 import jdk.vm.ci.code.Register;
136 import jdk.vm.ci.code.TargetDescription;
137 import jdk.vm.ci.meta.DeoptimizationAction;
138 import jdk.vm.ci.meta.DeoptimizationReason;
139 import jdk.vm.ci.meta.JavaType;
140 import jdk.vm.ci.meta.ResolvedJavaType;
141
142 /**
143 * Snippets used for implementing the monitorenter and monitorexit instructions.
144 *
145 * The locking algorithm used is described in the paper
146 * <a href="http://dl.acm.org/citation.cfm?id=1167515.1167496"> Eliminating synchronization-related
147 * atomic operations with biased locking and bulk rebiasing</a> by Kenneth Russell and David
148 * Detlefs.
149 *
150 * Comment below is reproduced from {@code markOop.hpp} for convenience:
151 *
152 * <pre>
153 * Bit-format of an object header (most significant first, big endian layout below):
154 * 32 bits:
155 * --------
156 * hash:25 ------------>| age:4 biased_lock:1 lock:2 (normal object)
157 * JavaThread*:23 epoch:2 age:4 biased_lock:1 lock:2 (biased object)
158 * size:32 ------------------------------------------>| (CMS free block)
159 * PromotedObject*:29 ---------->| promo_bits:3 ----->| (CMS promoted object)
160 *
161 * 64 bits:
162 * --------
163 * unused:25 hash:31 -->| unused:1 age:4 biased_lock:1 lock:2 (normal object)
164 * JavaThread*:54 epoch:2 unused:1 age:4 biased_lock:1 lock:2 (biased object)
165 * PromotedObject*:61 --------------------->| promo_bits:3 ----->| (CMS promoted object)
166 * size:64 ----------------------------------------------------->| (CMS free block)
167 *
168 * unused:25 hash:31 -->| cms_free:1 age:4 biased_lock:1 lock:2 (COOPs && normal object)
169 * JavaThread*:54 epoch:2 cms_free:1 age:4 biased_lock:1 lock:2 (COOPs && biased object)
170 * narrowOop:32 unused:24 cms_free:1 unused:4 promo_bits:3 ----->| (COOPs && CMS promoted object)
171 * unused:21 size:35 -->| cms_free:1 unused:7 ------------------>| (COOPs && CMS free block)
172 *
173 * - hash contains the identity hash value: largest value is
174 * 31 bits, see os::random(). Also, 64-bit vm's require
175 * a hash value no bigger than 32 bits because they will not
176 * properly generate a mask larger than that: see library_call.cpp
177 * and c1_CodePatterns_sparc.cpp.
178 *
179 * - the biased lock pattern is used to bias a lock toward a given
180 * thread. When this pattern is set in the low three bits, the lock
181 * is either biased toward a given thread or "anonymously" biased,
182 * indicating that it is possible for it to be biased. When the
183 * lock is biased toward a given thread, locking and unlocking can
184 * be performed by that thread without using atomic operations.
185 * When a lock's bias is revoked, it reverts back to the normal
186 * locking scheme described below.
187 *
188 * Note that we are overloading the meaning of the "unlocked" state
189 * of the header. Because we steal a bit from the age we can
190 * guarantee that the bias pattern will never be seen for a truly
191 * unlocked object.
192 *
193 * Note also that the biased state contains the age bits normally
194 * contained in the object header. Large increases in scavenge
195 * times were seen when these bits were absent and an arbitrary age
196 * assigned to all biased objects, because they tended to consume a
197 * significant fraction of the eden semispaces and were not
198 * promoted promptly, causing an increase in the amount of copying
199 * performed. The runtime system aligns all JavaThread* pointers to
200 * a very large value (currently 128 bytes (32bVM) or 256 bytes (64bVM))
201 * to make room for the age bits & the epoch bits (used in support of
202 * biased locking), and for the CMS "freeness" bit in the 64bVM (+COOPs).
203 *
204 * [JavaThread* | epoch | age | 1 | 01] lock is biased toward given thread
205 * [0 | epoch | age | 1 | 01] lock is anonymously biased
206 *
207 * - the two lock bits are used to describe three states: locked/unlocked and monitor.
208 *
209 * [ptr | 00] locked ptr points to real header on stack
210 * [header | 0 | 01] unlocked regular object header
211 * [ptr | 10] monitor inflated lock (header is wapped out)
212 * [ptr | 11] marked used by markSweep to mark an object
213 * not valid at any other time
214 *
215 * We assume that stack/thread pointers have the lowest two bits cleared.
216 * </pre>
217 *
218 * Note that {@code Thread::allocate} enforces {@code JavaThread} objects to be aligned
219 * appropriately to comply with the layouts above.
220 */
221 public class MonitorSnippets implements Snippets {
222
223 private static final boolean PROFILE_CONTEXT = false;
224
225 @Fold
226 static boolean doProfile(@Fold.InjectedParameter OptionValues options) {
227 return ProfileMonitors.getValue(options);
228 }
229
230 @Snippet
231 public static void monitorenter(Object object, KlassPointer hub, @ConstantParameter int lockDepth, @ConstantParameter Register threadRegister, @ConstantParameter Register stackPointerRegister,
232 @ConstantParameter boolean trace, @ConstantParameter Counters counters) {
233 verifyOop(object);
234
235 // Load the mark word - this includes a null-check on object
236 final Word mark = loadWordFromObject(object, markOffset(INJECTED_VMCONFIG));
237
238 final Word lock = beginLockScope(lockDepth);
239
240 Pointer objectPointer = Word.objectToTrackedPointer(object);
241 trace(trace, " object: 0x%016lx\n", objectPointer);
242 trace(trace, " lock: 0x%016lx\n", lock);
243 trace(trace, " mark: 0x%016lx\n", mark);
244
245 incCounter();
246
247 if (useBiasedLocking(INJECTED_VMCONFIG)) {
248 if (tryEnterBiased(object, hub, lock, mark, threadRegister, trace, counters)) {
249 return;
250 }
251 // not biased, fall-through
252 }
253 if (inlineFastLockSupported() && probability(SLOW_PATH_PROBABILITY, mark.and(monitorMask(INJECTED_VMCONFIG)).notEqual(0))) {
254 // Inflated case
255 if (tryEnterInflated(object, lock, mark, threadRegister, trace, counters)) {
256 return;
257 }
258 } else {
259 // Create the unlocked mark word pattern
260 Word unlockedMark = mark.or(unlockedMask(INJECTED_VMCONFIG));
261 trace(trace, " unlockedMark: 0x%016lx\n", unlockedMark);
262
263 // Copy this unlocked mark word into the lock slot on the stack
264 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), unlockedMark, DISPLACED_MARK_WORD_LOCATION);
265
266 // make sure previous store does not float below compareAndSwap
267 MembarNode.memoryBarrier(STORE_STORE);
268
269 // Test if the object's mark word is unlocked, and if so, store the
270 // (address of) the lock slot into the object's mark word.
271 Word currentMark = objectPointer.compareAndSwapWord(markOffset(INJECTED_VMCONFIG), unlockedMark, lock, MARK_WORD_LOCATION);
272 if (probability(FAST_PATH_PROBABILITY, currentMark.equal(unlockedMark))) {
273 traceObject(trace, "+lock{cas}", object, true);
274 counters.lockCas.inc();
275 mark(object);
276 return;
277 } else {
278 trace(trace, " currentMark: 0x%016lx\n", currentMark);
279 // The mark word in the object header was not the same.
280 // Either the object is locked by another thread or is already locked
281 // by the current thread. The latter is true if the mark word
282 // is a stack pointer into the current thread's stack, i.e.:
283 //
284 // 1) (currentMark & aligned_mask) == 0
285 // 2) rsp <= currentMark
286 // 3) currentMark <= rsp + page_size
287 //
288 // These 3 tests can be done by evaluating the following expression:
289 //
290 // (currentMark - rsp) & (aligned_mask - page_size)
291 //
292 // assuming both the stack pointer and page_size have their least
293 // significant 2 bits cleared and page_size is a power of 2
294 final Word alignedMask = unsigned(wordSize() - 1);
295 final Word stackPointer = registerAsWord(stackPointerRegister).add(stackBias(INJECTED_VMCONFIG));
296 if (probability(FAST_PATH_PROBABILITY, currentMark.subtract(stackPointer).and(alignedMask.subtract(pageSize(INJECTED_VMCONFIG))).equal(0))) {
297 // Recursively locked => write 0 to the lock slot
298 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), zero(), DISPLACED_MARK_WORD_LOCATION);
299 traceObject(trace, "+lock{cas:recursive}", object, true);
300 counters.lockCasRecursive.inc();
301 return;
302 }
303 traceObject(trace, "+lock{stub:failed-cas/stack}", object, true);
304 counters.lockStubFailedCas.inc();
305 }
306 }
307 // slow-path runtime-call
308 monitorenterStubC(MONITORENTER, object, lock);
309 }
310
311 private static boolean tryEnterBiased(Object object, KlassPointer hub, Word lock, Word mark, Register threadRegister, boolean trace, Counters counters) {
312 // See whether the lock is currently biased toward our thread and
313 // whether the epoch is still valid.
314 // Note that the runtime guarantees sufficient alignment of JavaThread
315 // pointers to allow age to be placed into low bits.
316 final Word biasableLockBits = mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG));
317
318 // Check whether the bias pattern is present in the object's mark word
319 // and the bias owner and the epoch are both still current.
320 final Word prototypeMarkWord = hub.readWord(prototypeMarkWordOffset(INJECTED_VMCONFIG), PROTOTYPE_MARK_WORD_LOCATION);
321 final Word thread = registerAsWord(threadRegister);
322 final Word tmp = prototypeMarkWord.or(thread).xor(mark).and(~ageMaskInPlace(INJECTED_VMCONFIG));
323 trace(trace, "prototypeMarkWord: 0x%016lx\n", prototypeMarkWord);
324 trace(trace, " thread: 0x%016lx\n", thread);
325 trace(trace, " tmp: 0x%016lx\n", tmp);
326 if (probability(FAST_PATH_PROBABILITY, tmp.equal(0))) {
327 // Object is already biased to current thread -> done
328 traceObject(trace, "+lock{bias:existing}", object, true);
329 counters.lockBiasExisting.inc();
330 FastAcquireBiasedLockNode.mark(object);
331 return true;
332 }
333
334 // Now check to see whether biasing is enabled for this object
335 if (probability(NOT_FREQUENT_PROBABILITY, biasableLockBits.equal(WordFactory.unsigned(biasedLockPattern(INJECTED_VMCONFIG))))) {
336 Pointer objectPointer = Word.objectToTrackedPointer(object);
337 // At this point we know that the mark word has the bias pattern and
338 // that we are not the bias owner in the current epoch. We need to
339 // figure out more details about the state of the mark word in order to
340 // know what operations can be legally performed on the object's
341 // mark word.
342
343 // If the low three bits in the xor result aren't clear, that means
344 // the prototype header is no longer biasable and we have to revoke
345 // the bias on this object.
346 if (probability(FREQUENT_PROBABILITY, tmp.and(biasedLockMaskInPlace(INJECTED_VMCONFIG)).equal(0))) {
347 // Biasing is still enabled for object's type. See whether the
348 // epoch of the current bias is still valid, meaning that the epoch
349 // bits of the mark word are equal to the epoch bits of the
350 // prototype mark word. (Note that the prototype mark word's epoch bits
351 // only change at a safepoint.) If not, attempt to rebias the object
352 // toward the current thread. Note that we must be absolutely sure
353 // that the current epoch is invalid in order to do this because
354 // otherwise the manipulations it performs on the mark word are
355 // illegal.
356 if (probability(FREQUENT_PROBABILITY, tmp.and(epochMaskInPlace(INJECTED_VMCONFIG)).equal(0))) {
357 // The epoch of the current bias is still valid but we know nothing
358 // about the owner; it might be set or it might be clear. Try to
359 // acquire the bias of the object using an atomic operation. If this
360 // fails we will go in to the runtime to revoke the object's bias.
361 // Note that we first construct the presumed unbiased header so we
362 // don't accidentally blow away another thread's valid bias.
363 Word unbiasedMark = mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG) | ageMaskInPlace(INJECTED_VMCONFIG) | epochMaskInPlace(INJECTED_VMCONFIG));
364 Word biasedMark = unbiasedMark.or(thread);
365 trace(trace, " unbiasedMark: 0x%016lx\n", unbiasedMark);
366 trace(trace, " biasedMark: 0x%016lx\n", biasedMark);
367 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), unbiasedMark, biasedMark, MARK_WORD_LOCATION))) {
368 // Object is now biased to current thread -> done
369 traceObject(trace, "+lock{bias:acquired}", object, true);
370 counters.lockBiasAcquired.inc();
371 return true;
372 }
373 // If the biasing toward our thread failed, this means that another thread
374 // owns the bias and we need to revoke that bias. The revocation will occur
375 // in the interpreter runtime.
376 traceObject(trace, "+lock{stub:revoke}", object, true);
377 counters.lockStubRevoke.inc();
378 } else {
379 // At this point we know the epoch has expired, meaning that the
380 // current bias owner, if any, is actually invalid. Under these
381 // circumstances _only_, are we allowed to use the current mark word
382 // value as the comparison value when doing the CAS to acquire the
383 // bias in the current epoch. In other words, we allow transfer of
384 // the bias from one thread to another directly in this situation.
385 Word biasedMark = prototypeMarkWord.or(thread);
386 trace(trace, " biasedMark: 0x%016lx\n", biasedMark);
387 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), mark, biasedMark, MARK_WORD_LOCATION))) {
388 // Object is now biased to current thread -> done
389 traceObject(trace, "+lock{bias:transfer}", object, true);
390 counters.lockBiasTransfer.inc();
391 return true;
392 }
393 // If the biasing toward our thread failed, then another thread
394 // succeeded in biasing it toward itself and we need to revoke that
395 // bias. The revocation will occur in the runtime in the slow case.
396 traceObject(trace, "+lock{stub:epoch-expired}", object, true);
397 counters.lockStubEpochExpired.inc();
398 }
399 // slow-path runtime-call
400 monitorenterStubC(MONITORENTER, object, lock);
401 return true;
402 } else {
403 // The prototype mark word doesn't have the bias bit set any
404 // more, indicating that objects of this data type are not supposed
405 // to be biased any more. We are going to try to reset the mark of
406 // this object to the prototype value and fall through to the
407 // CAS-based locking scheme. Note that if our CAS fails, it means
408 // that another thread raced us for the privilege of revoking the
409 // bias of this particular object, so it's okay to continue in the
410 // normal locking code.
411 Word result = objectPointer.compareAndSwapWord(markOffset(INJECTED_VMCONFIG), mark, prototypeMarkWord, MARK_WORD_LOCATION);
412
413 // Fall through to the normal CAS-based lock, because no matter what
414 // the result of the above CAS, some thread must have succeeded in
415 // removing the bias bit from the object's header.
416
417 if (ENABLE_BREAKPOINT) {
418 bkpt(object, mark, tmp, result);
419 }
420 counters.revokeBias.inc();
421 return false;
422 }
423 } else {
424 // Biasing not enabled -> fall through to lightweight locking
425 counters.unbiasable.inc();
426 return false;
427 }
428 }
429
430 @Fold
431 public static boolean useFastInflatedLocking(@Fold.InjectedParameter OptionValues options) {
432 return SimpleFastInflatedLocking.getValue(options);
433 }
434
435 private static boolean inlineFastLockSupported() {
436 return inlineFastLockSupported(INJECTED_VMCONFIG, INJECTED_OPTIONVALUES);
437 }
438
439 private static boolean inlineFastLockSupported(GraalHotSpotVMConfig config, OptionValues options) {
440 return useFastInflatedLocking(options) && monitorMask(config) >= 0 && objectMonitorOwnerOffset(config) >= 0;
441 }
442
443 private static boolean tryEnterInflated(Object object, Word lock, Word mark, Register threadRegister, boolean trace, Counters counters) {
444 // write non-zero value to lock slot
445 lock.writeWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), lock, DISPLACED_MARK_WORD_LOCATION);
446 // mark is a pointer to the ObjectMonitor + monitorMask
447 Word monitor = mark.subtract(monitorMask(INJECTED_VMCONFIG));
448 int ownerOffset = objectMonitorOwnerOffset(INJECTED_VMCONFIG);
449 Word owner = monitor.readWord(ownerOffset, OBJECT_MONITOR_OWNER_LOCATION);
450 if (probability(FREQUENT_PROBABILITY, owner.equal(0))) {
451 // it appears unlocked (owner == 0)
452 if (probability(FREQUENT_PROBABILITY, monitor.logicCompareAndSwapWord(ownerOffset, owner, registerAsWord(threadRegister), OBJECT_MONITOR_OWNER_LOCATION))) {
453 // success
454 traceObject(trace, "+lock{inflated:cas}", object, true);
455 counters.inflatedCas.inc();
456 return true;
457 } else {
458 traceObject(trace, "+lock{stub:inflated:failed-cas}", object, true);
459 counters.inflatedFailedCas.inc();
460 }
461 } else {
462 traceObject(trace, "+lock{stub:inflated:owned}", object, true);
463 counters.inflatedOwned.inc();
464 }
465 return false;
466 }
467
468 /**
469 * Calls straight out to the monitorenter stub.
470 */
471 @Snippet
472 public static void monitorenterStub(Object object, @ConstantParameter int lockDepth, @ConstantParameter boolean trace) {
473 verifyOop(object);
474 incCounter();
475 if (object == null) {
476 DeoptimizeNode.deopt(DeoptimizationAction.InvalidateReprofile, DeoptimizationReason.NullCheckException);
477 }
478 // BeginLockScope nodes do not read from object so a use of object
479 // cannot float about the null check above
480 final Word lock = beginLockScope(lockDepth);
481 traceObject(trace, "+lock{stub}", object, true);
482 monitorenterStubC(MONITORENTER, object, lock);
483 }
484
485 @Snippet
486 public static void monitorexit(Object object, @ConstantParameter int lockDepth, @ConstantParameter Register threadRegister, @ConstantParameter boolean trace,
487 @ConstantParameter Counters counters) {
488 trace(trace, " object: 0x%016lx\n", Word.objectToTrackedPointer(object));
489 final Word mark = loadWordFromObject(object, markOffset(INJECTED_VMCONFIG));
490 if (useBiasedLocking(INJECTED_VMCONFIG)) {
491 // Check for biased locking unlock case, which is a no-op
492 // Note: we do not have to check the thread ID for two reasons.
493 // First, the interpreter checks for IllegalMonitorStateException at
494 // a higher level. Second, if the bias was revoked while we held the
495 // lock, the object could not be rebiased toward another thread, so
496 // the bias bit would be clear.
497 trace(trace, " mark: 0x%016lx\n", mark);
498 if (probability(FREQUENT_PROBABILITY, mark.and(biasedLockMaskInPlace(INJECTED_VMCONFIG)).equal(WordFactory.unsigned(biasedLockPattern(INJECTED_VMCONFIG))))) {
499 endLockScope();
500 decCounter();
501 traceObject(trace, "-lock{bias}", object, false);
502 counters.unlockBias.inc();
503 return;
504 }
505 }
506
507 final Word lock = CurrentLockNode.currentLock(lockDepth);
508
509 // Load displaced mark
510 final Word displacedMark = lock.readWord(lockDisplacedMarkOffset(INJECTED_VMCONFIG), DISPLACED_MARK_WORD_LOCATION);
511 trace(trace, " displacedMark: 0x%016lx\n", displacedMark);
512
513 if (probability(NOT_LIKELY_PROBABILITY, displacedMark.equal(0))) {
514 // Recursive locking => done
515 traceObject(trace, "-lock{recursive}", object, false);
516 counters.unlockCasRecursive.inc();
517 } else {
518 if (!tryExitInflated(object, mark, lock, threadRegister, trace, counters)) {
519 verifyOop(object);
520 // Test if object's mark word is pointing to the displaced mark word, and if so,
521 // restore
522 // the displaced mark in the object - if the object's mark word is not pointing to
523 // the displaced mark word, do unlocking via runtime call.
524 Pointer objectPointer = Word.objectToTrackedPointer(object);
525 if (probability(VERY_FAST_PATH_PROBABILITY, objectPointer.logicCompareAndSwapWord(markOffset(INJECTED_VMCONFIG), lock, displacedMark, MARK_WORD_LOCATION))) {
526 traceObject(trace, "-lock{cas}", object, false);
527 counters.unlockCas.inc();
528 } else {
529 // The object's mark word was not pointing to the displaced header
530 traceObject(trace, "-lock{stub}", object, false);
531 counters.unlockStub.inc();
532 monitorexitStubC(MONITOREXIT, object, lock);
533 }
534 }
535 }
536 endLockScope();
537 decCounter();
538 }
539
540 private static boolean inlineFastUnlockSupported(OptionValues options) {
541 return inlineFastUnlockSupported(INJECTED_VMCONFIG, options);
542 }
543
544 private static boolean inlineFastUnlockSupported(GraalHotSpotVMConfig config, OptionValues options) {
545 return useFastInflatedLocking(options) && objectMonitorEntryListOffset(config) >= 0 && objectMonitorCxqOffset(config) >= 0 && monitorMask(config) >= 0 &&
546 objectMonitorOwnerOffset(config) >= 0 && objectMonitorRecursionsOffset(config) >= 0;
547 }
548
549 private static boolean tryExitInflated(Object object, Word mark, Word lock, Register threadRegister, boolean trace, Counters counters) {
550 if (!inlineFastUnlockSupported(INJECTED_OPTIONVALUES)) {
551 return false;
552 }
553 if (probability(SLOW_PATH_PROBABILITY, mark.and(monitorMask(INJECTED_VMCONFIG)).notEqual(0))) {
554 // Inflated case
555 // mark is a pointer to the ObjectMonitor + monitorMask
556 Word monitor = mark.subtract(monitorMask(INJECTED_VMCONFIG));
557 int ownerOffset = objectMonitorOwnerOffset(INJECTED_VMCONFIG);
558 Word owner = monitor.readWord(ownerOffset, OBJECT_MONITOR_OWNER_LOCATION);
559 int recursionsOffset = objectMonitorRecursionsOffset(INJECTED_VMCONFIG);
560 Word recursions = monitor.readWord(recursionsOffset, OBJECT_MONITOR_RECURSION_LOCATION);
561 Word thread = registerAsWord(threadRegister);
562 if (probability(FAST_PATH_PROBABILITY, owner.xor(thread).or(recursions).equal(0))) {
563 // owner == thread && recursions == 0
564 int cxqOffset = objectMonitorCxqOffset(INJECTED_VMCONFIG);
565 Word cxq = monitor.readWord(cxqOffset, OBJECT_MONITOR_CXQ_LOCATION);
566 int entryListOffset = objectMonitorEntryListOffset(INJECTED_VMCONFIG);
567 Word entryList = monitor.readWord(entryListOffset, OBJECT_MONITOR_ENTRY_LIST_LOCATION);
568 if (probability(FREQUENT_PROBABILITY, cxq.or(entryList).equal(0))) {
569 // cxq == 0 && entryList == 0
570 // Nobody is waiting, success
571 // release_store
572 memoryBarrier(LOAD_STORE | STORE_STORE);
573 monitor.writeWord(ownerOffset, zero());
574 traceObject(trace, "-lock{inflated:simple}", object, false);
575 counters.unlockInflatedSimple.inc();
576 return true;
577 }
578 }
579 counters.unlockStubInflated.inc();
580 traceObject(trace, "-lock{stub:inflated}", object, false);
581 monitorexitStubC(MONITOREXIT, object, lock);
582 return true;
583 }
584 return false;
585 }
586
587 /**
588 * Calls straight out to the monitorexit stub.
589 */
590 @Snippet
591 public static void monitorexitStub(Object object, @ConstantParameter int lockDepth, @ConstantParameter boolean trace) {
592 verifyOop(object);
593 traceObject(trace, "-lock{stub}", object, false);
594 final Word lock = CurrentLockNode.currentLock(lockDepth);
595 monitorexitStubC(MONITOREXIT, object, lock);
596 endLockScope();
597 decCounter();
598 }
599
600 public static void traceObject(boolean enabled, String action, Object object, boolean enter) {
601 if (doProfile(INJECTED_OPTIONVALUES)) {
602 DynamicCounterNode.counter(enter ? "number of monitor enters" : "number of monitor exits", action, 1, PROFILE_CONTEXT);
603 }
604 if (enabled) {
605 Log.print(action);
606 Log.print(' ');
607 Log.printlnObject(object);
608 }
609 }
610
611 public static void trace(boolean enabled, String format, WordBase value) {
612 if (enabled) {
613 Log.printf(format, value.rawValue());
614 }
615 }
616
617 /**
618 * Leaving the breakpoint code in to provide an example of how to use the {@link BreakpointNode}
619 * intrinsic.
620 */
621 private static final boolean ENABLE_BREAKPOINT = false;
622
623 private static final LocationIdentity MONITOR_COUNTER_LOCATION = NamedLocationIdentity.mutable("MonitorCounter");
624
625 @NodeIntrinsic(BreakpointNode.class)
626 static native void bkpt(Object object, Word mark, Word tmp, Word value);
627
628 @Fold
629 static boolean verifyBalancedMonitors(@Fold.InjectedParameter OptionValues options) {
630 return VerifyBalancedMonitors.getValue(options);
631 }
632
633 static void incCounter() {
634 if (verifyBalancedMonitors(INJECTED_OPTIONVALUES)) {
635 final Word counter = MonitorCounterNode.counter();
636 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
637 counter.writeInt(0, count + 1, MONITOR_COUNTER_LOCATION);
638 }
639 }
640
641 public static void decCounter() {
642 if (verifyBalancedMonitors(INJECTED_OPTIONVALUES)) {
643 final Word counter = MonitorCounterNode.counter();
644 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
645 counter.writeInt(0, count - 1, MONITOR_COUNTER_LOCATION);
646 }
647 }
648
649 @Snippet
650 private static void initCounter() {
651 final Word counter = MonitorCounterNode.counter();
652 counter.writeInt(0, 0, MONITOR_COUNTER_LOCATION);
653 }
654
655 @Snippet
656 private static void checkCounter(@ConstantParameter String errMsg) {
657 final Word counter = MonitorCounterNode.counter();
658 final int count = counter.readInt(0, MONITOR_COUNTER_LOCATION);
659 if (count != 0) {
660 vmError(errMsg, count);
661 }
662 }
663
664 public static class Counters {
665 /**
666 * Counters for the various paths for acquiring a lock. The counters whose names start with
667 * {@code "lock"} are mutually exclusive. The other counters are for paths that may be
668 * shared.
669 */
670 public final SnippetCounter lockBiasExisting;
671 public final SnippetCounter lockBiasAcquired;
672 public final SnippetCounter lockBiasTransfer;
673 public final SnippetCounter lockCas;
674 public final SnippetCounter lockCasRecursive;
675 public final SnippetCounter lockStubEpochExpired;
676 public final SnippetCounter lockStubRevoke;
677 public final SnippetCounter lockStubFailedCas;
678 public final SnippetCounter inflatedCas;
679 public final SnippetCounter inflatedFailedCas;
680 public final SnippetCounter inflatedOwned;
681 public final SnippetCounter unbiasable;
682 public final SnippetCounter revokeBias;
683
684 /**
685 * Counters for the various paths for releasing a lock. The counters whose names start with
686 * {@code "unlock"} are mutually exclusive. The other counters are for paths that may be
687 * shared.
688 */
689 public final SnippetCounter unlockBias;
690 public final SnippetCounter unlockCas;
691 public final SnippetCounter unlockCasRecursive;
692 public final SnippetCounter unlockStub;
693 public final SnippetCounter unlockStubInflated;
694 public final SnippetCounter unlockInflatedSimple;
695
696 public Counters(SnippetCounter.Group.Factory factory) {
697 SnippetCounter.Group enter = factory.createSnippetCounterGroup("MonitorEnters");
698 SnippetCounter.Group exit = factory.createSnippetCounterGroup("MonitorExits");
699 lockBiasExisting = new SnippetCounter(enter, "lock{bias:existing}", "bias-locked previously biased object");
700 lockBiasAcquired = new SnippetCounter(enter, "lock{bias:acquired}", "bias-locked newly biased object");
701 lockBiasTransfer = new SnippetCounter(enter, "lock{bias:transfer}", "bias-locked, biased transferred");
702 lockCas = new SnippetCounter(enter, "lock{cas}", "cas-locked an object");
703 lockCasRecursive = new SnippetCounter(enter, "lock{cas:recursive}", "cas-locked, recursive");
704 lockStubEpochExpired = new SnippetCounter(enter, "lock{stub:epoch-expired}", "stub-locked, epoch expired");
705 lockStubRevoke = new SnippetCounter(enter, "lock{stub:revoke}", "stub-locked, biased revoked");
706 lockStubFailedCas = new SnippetCounter(enter, "lock{stub:failed-cas/stack}", "stub-locked, failed cas and stack locking");
707 inflatedCas = new SnippetCounter(enter, "lock{inflated:cas}", "heavyweight-locked, cas-locked");
708 inflatedFailedCas = new SnippetCounter(enter, "lock{inflated:failed-cas}", "heavyweight-locked, failed cas");
709 inflatedOwned = new SnippetCounter(enter, "lock{inflated:owned}", "heavyweight-locked, already owned");
710 unbiasable = new SnippetCounter(enter, "unbiasable", "object with unbiasable type");
711 revokeBias = new SnippetCounter(enter, "revokeBias", "object had bias revoked");
712
713 unlockBias = new SnippetCounter(exit, "unlock{bias}", "bias-unlocked an object");
714 unlockCas = new SnippetCounter(exit, "unlock{cas}", "cas-unlocked an object");
715 unlockCasRecursive = new SnippetCounter(exit, "unlock{cas:recursive}", "cas-unlocked an object, recursive");
716 unlockStub = new SnippetCounter(exit, "unlock{stub}", "stub-unlocked an object");
717 unlockStubInflated = new SnippetCounter(exit, "unlock{stub:inflated}", "stub-unlocked an object with inflated monitor");
718 unlockInflatedSimple = new SnippetCounter(exit, "unlock{inflated}", "unlocked an object monitor");
719 }
720 }
721
722 public static class Templates extends AbstractTemplates {
723
724 private final SnippetInfo monitorenter = snippet(MonitorSnippets.class, "monitorenter");
725 private final SnippetInfo monitorexit = snippet(MonitorSnippets.class, "monitorexit");
726 private final SnippetInfo monitorenterStub = snippet(MonitorSnippets.class, "monitorenterStub");
727 private final SnippetInfo monitorexitStub = snippet(MonitorSnippets.class, "monitorexitStub");
728 private final SnippetInfo initCounter = snippet(MonitorSnippets.class, "initCounter");
729 private final SnippetInfo checkCounter = snippet(MonitorSnippets.class, "checkCounter");
730
731 private final boolean useFastLocking;
732 public final Counters counters;
733
734 public Templates(OptionValues options, Iterable<DebugHandlersFactory> factories, SnippetCounter.Group.Factory factory, HotSpotProviders providers, TargetDescription target,
735 boolean useFastLocking) {
736 super(options, factories, providers, providers.getSnippetReflection(), target);
737 this.useFastLocking = useFastLocking;
738
739 this.counters = new Counters(factory);
740 }
741
742 public void lower(RawMonitorEnterNode monitorenterNode, HotSpotRegistersProvider registers, LoweringTool tool) {
743 StructuredGraph graph = monitorenterNode.graph();
744 checkBalancedMonitors(graph, tool);
745
746 assert ((ObjectStamp) monitorenterNode.object().stamp(NodeView.DEFAULT)).nonNull();
747
748 Arguments args;
749 if (useFastLocking) {
750 args = new Arguments(monitorenter, graph.getGuardsStage(), tool.getLoweringStage());
751 args.add("object", monitorenterNode.object());
752 args.add("hub", monitorenterNode.getHub());
753 args.addConst("lockDepth", monitorenterNode.getMonitorId().getLockDepth());
754 args.addConst("threadRegister", registers.getThreadRegister());
755 args.addConst("stackPointerRegister", registers.getStackPointerRegister());
756 args.addConst("trace", isTracingEnabledForType(monitorenterNode.object()) || isTracingEnabledForMethod(graph));
757 args.addConst("counters", counters);
758 } else {
759 args = new Arguments(monitorenterStub, graph.getGuardsStage(), tool.getLoweringStage());
760 args.add("object", monitorenterNode.object());
761 args.addConst("lockDepth", monitorenterNode.getMonitorId().getLockDepth());
762 args.addConst("trace", isTracingEnabledForType(monitorenterNode.object()) || isTracingEnabledForMethod(graph));
763 args.addConst("counters", counters);
764 }
765
766 template(monitorenterNode, args).instantiate(providers.getMetaAccess(), monitorenterNode, DEFAULT_REPLACER, args);
767 }
768
769 public void lower(MonitorExitNode monitorexitNode, HotSpotRegistersProvider registers, LoweringTool tool) {
770 StructuredGraph graph = monitorexitNode.graph();
771
772 Arguments args;
773 if (useFastLocking) {
774 args = new Arguments(monitorexit, graph.getGuardsStage(), tool.getLoweringStage());
775 } else {
776 args = new Arguments(monitorexitStub, graph.getGuardsStage(), tool.getLoweringStage());
777 }
778 args.add("object", monitorexitNode.object());
779 args.addConst("lockDepth", monitorexitNode.getMonitorId().getLockDepth());
780 args.addConst("threadRegister", registers.getThreadRegister());
781 args.addConst("trace", isTracingEnabledForType(monitorexitNode.object()) || isTracingEnabledForMethod(graph));
782 args.addConst("counters", counters);
783
784 template(monitorexitNode, args).instantiate(providers.getMetaAccess(), monitorexitNode, DEFAULT_REPLACER, args);
785 }
786
787 public static boolean isTracingEnabledForType(ValueNode object) {
788 ResolvedJavaType type = StampTool.typeOrNull(object.stamp(NodeView.DEFAULT));
789 String filter = TraceMonitorsTypeFilter.getValue(object.getOptions());
790 if (filter == null) {
791 return false;
792 } else {
793 if (filter.length() == 0) {
794 return true;
795 }
796 if (type == null) {
797 return false;
798 }
799 return (type.getName().contains(filter));
800 }
801 }
802
803 public static boolean isTracingEnabledForMethod(StructuredGraph graph) {
804 String filter = TraceMonitorsMethodFilter.getValue(graph.getOptions());
805 if (filter == null) {
806 return false;
807 } else {
808 if (filter.length() == 0) {
809 return true;
810 }
811 if (graph.method() == null) {
812 return false;
813 }
814 return (graph.method().format("%H.%n").contains(filter));
815 }
816 }
817
818 /**
819 * If balanced monitor checking is enabled then nodes are inserted at the start and all
820 * return points of the graph to initialize and check the monitor counter respectively.
821 */
822 private void checkBalancedMonitors(StructuredGraph graph, LoweringTool tool) {
823 if (VerifyBalancedMonitors.getValue(options)) {
824 NodeIterable<MonitorCounterNode> nodes = graph.getNodes().filter(MonitorCounterNode.class);
825 if (nodes.isEmpty()) {
826 // Only insert the nodes if this is the first monitorenter being lowered.
827 JavaType returnType = initCounter.getMethod().getSignature().getReturnType(initCounter.getMethod().getDeclaringClass());
828 StampPair returnStamp = StampFactory.forDeclaredType(graph.getAssumptions(), returnType, false);
829 MethodCallTargetNode callTarget = graph.add(new MethodCallTargetNode(InvokeKind.Static, initCounter.getMethod(), new ValueNode[0], returnStamp, null));
830 InvokeNode invoke = graph.add(new InvokeNode(callTarget, 0));
831 invoke.setStateAfter(graph.start().stateAfter());
832 graph.addAfterFixed(graph.start(), invoke);
833
834 StructuredGraph inlineeGraph = providers.getReplacements().getSnippet(initCounter.getMethod(), null, null, invoke.graph().trackNodeSourcePosition(), invoke.getNodeSourcePosition(),
835 invoke.getOptions());
836 InliningUtil.inline(invoke, inlineeGraph, false, null);
837
838 List<ReturnNode> rets = graph.getNodes(ReturnNode.TYPE).snapshot();
839 for (ReturnNode ret : rets) {
840 returnType = checkCounter.getMethod().getSignature().getReturnType(checkCounter.getMethod().getDeclaringClass());
841 String msg = "unbalanced monitors in " + graph.method().format("%H.%n(%p)") + ", count = %d";
842 ConstantNode errMsg = ConstantNode.forConstant(tool.getConstantReflection().forString(msg), providers.getMetaAccess(), graph);
843 returnStamp = StampFactory.forDeclaredType(graph.getAssumptions(), returnType, false);
844 callTarget = graph.add(new MethodCallTargetNode(InvokeKind.Static, checkCounter.getMethod(), new ValueNode[]{errMsg}, returnStamp, null));
845 invoke = graph.add(new InvokeNode(callTarget, 0));
846 Bytecode code = new ResolvedJavaMethodBytecode(graph.method());
847 FrameState stateAfter = new FrameState(null, code, BytecodeFrame.AFTER_BCI, new ValueNode[0], new ValueNode[0], 0, new ValueNode[0], null, false, false);
848 invoke.setStateAfter(graph.add(stateAfter));
849 graph.addBeforeFixed(ret, invoke);
850
851 Arguments args = new Arguments(checkCounter, graph.getGuardsStage(), tool.getLoweringStage());
852 args.addConst("errMsg", msg);
853 inlineeGraph = template(invoke, args).copySpecializedGraph(graph.getDebug());
854 InliningUtil.inline(invoke, inlineeGraph, false, null);
855 }
856 }
857 }
858 }
859 }
860
861 public static final ForeignCallDescriptor MONITORENTER = new ForeignCallDescriptor("monitorenter", void.class, Object.class, Word.class);
862 public static final ForeignCallDescriptor MONITOREXIT = new ForeignCallDescriptor("monitorexit", void.class, Object.class, Word.class);
863
864 @NodeIntrinsic(ForeignCallNode.class)
865 private static native void monitorenterStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
866
867 @NodeIntrinsic(ForeignCallNode.class)
868 public static native void monitorexitStubC(@ConstantNodeParameter ForeignCallDescriptor descriptor, Object object, Word lock);
869 }