1 /*
2 * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/dynamicArchive.hpp"
28 #include "ci/ciEnv.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/javaThreadStatus.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmClasses.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/codeCache.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/oopStorage.hpp"
39 #include "gc/shared/oopStorageSet.hpp"
40 #include "gc/shared/tlab_globals.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jvm.h"
43 #include "jvmtifiles/jvmtiEnv.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logAsyncWriter.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/allocation.inline.hpp"
48 #include "memory/iterator.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/access.inline.hpp"
51 #include "oops/inlineKlass.hpp"
52 #include "oops/instanceKlass.hpp"
53 #include "oops/klass.inline.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "oops/oopHandle.inline.hpp"
56 #include "oops/verifyOopClosure.hpp"
57 #include "prims/jvm_misc.hpp"
58 #include "prims/jvmtiDeferredUpdates.hpp"
59 #include "prims/jvmtiExport.hpp"
60 #include "prims/jvmtiThreadState.inline.hpp"
61 #include "runtime/atomic.hpp"
62 #include "runtime/continuation.hpp"
63 #include "runtime/continuationEntry.inline.hpp"
64 #include "runtime/continuationHelper.inline.hpp"
65 #include "runtime/deoptimization.hpp"
66 #include "runtime/frame.inline.hpp"
67 #include "runtime/handles.inline.hpp"
68 #include "runtime/handshake.hpp"
69 #include "runtime/interfaceSupport.inline.hpp"
70 #include "runtime/java.hpp"
71 #include "runtime/javaCalls.hpp"
72 #include "runtime/javaThread.inline.hpp"
73 #include "runtime/jniHandles.inline.hpp"
74 #include "runtime/lockStack.inline.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.hpp"
77 #include "runtime/os.inline.hpp"
78 #include "runtime/osThread.hpp"
79 #include "runtime/safepoint.hpp"
80 #include "runtime/safepointMechanism.inline.hpp"
81 #include "runtime/safepointVerifiers.hpp"
82 #include "runtime/serviceThread.hpp"
83 #include "runtime/stackFrameStream.inline.hpp"
84 #include "runtime/stackWatermarkSet.hpp"
85 #include "runtime/synchronizer.hpp"
86 #include "runtime/threadCritical.hpp"
87 #include "runtime/threadSMR.inline.hpp"
88 #include "runtime/threadStatisticalInfo.hpp"
89 #include "runtime/threadWXSetters.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.inline.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vmOperations.hpp"
97 #include "services/threadService.hpp"
98 #include "utilities/copy.hpp"
99 #include "utilities/defaultStream.hpp"
100 #include "utilities/dtrace.hpp"
101 #include "utilities/events.hpp"
102 #include "utilities/macros.hpp"
103 #include "utilities/preserveException.hpp"
104 #include "utilities/spinYield.hpp"
105 #include "utilities/vmError.hpp"
106 #if INCLUDE_JVMCI
107 #include "jvmci/jvmci.hpp"
108 #include "jvmci/jvmciEnv.hpp"
109 #endif
110 #if INCLUDE_JFR
111 #include "jfr/jfr.hpp"
112 #endif
113
114 // Set by os layer.
115 size_t JavaThread::_stack_size_at_create = 0;
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
122 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
123
124 #define DTRACE_THREAD_PROBE(probe, javathread) \
125 { \
126 ResourceMark rm(this); \
127 int len = 0; \
128 const char* name = (javathread)->name(); \
129 len = strlen(name); \
130 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
131 (char *) name, len, \
132 java_lang_Thread::thread_id((javathread)->threadObj()), \
133 (uintptr_t) (javathread)->osthread()->thread_id(), \
134 java_lang_Thread::is_daemon((javathread)->threadObj())); \
135 }
136
137 #else // ndef DTRACE_ENABLED
138
139 #define DTRACE_THREAD_PROBE(probe, javathread)
140
141 #endif // ndef DTRACE_ENABLED
142
143 void JavaThread::smr_delete() {
144 if (_on_thread_list) {
145 ThreadsSMRSupport::smr_delete(this);
146 } else {
147 delete this;
148 }
149 }
150
151 // Initialized by VMThread at vm_global_init
152 OopStorage* JavaThread::_thread_oop_storage = nullptr;
153
154 OopStorage* JavaThread::thread_oop_storage() {
155 assert(_thread_oop_storage != nullptr, "not yet initialized");
156 return _thread_oop_storage;
157 }
158
159 void JavaThread::set_threadOopHandles(oop p) {
160 assert(_thread_oop_storage != nullptr, "not yet initialized");
161 _threadObj = OopHandle(_thread_oop_storage, p);
162 _vthread = OopHandle(_thread_oop_storage, p);
163 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
164 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
165 }
166
167 oop JavaThread::threadObj() const {
168 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
169 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
170 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
171 // Instead callers must verify oop safe access.
172 return _threadObj.resolve();
173 }
174
175 oop JavaThread::vthread() const {
176 return _vthread.resolve();
177 }
178
179 void JavaThread::set_vthread(oop p) {
180 assert(_thread_oop_storage != nullptr, "not yet initialized");
181 _vthread.replace(p);
182 }
183
184 oop JavaThread::jvmti_vthread() const {
185 return _jvmti_vthread.resolve();
186 }
187
188 void JavaThread::set_jvmti_vthread(oop p) {
189 assert(_thread_oop_storage != nullptr, "not yet initialized");
190 _jvmti_vthread.replace(p);
191 }
192
193 oop JavaThread::scopedValueCache() const {
194 return _scopedValueCache.resolve();
195 }
196
197 void JavaThread::set_scopedValueCache(oop p) {
198 if (_scopedValueCache.ptr_raw() != nullptr) { // i.e. if the OopHandle has been allocated
199 _scopedValueCache.replace(p);
200 } else {
201 assert(p == nullptr, "not yet initialized");
202 }
203 }
204
205 void JavaThread::clear_scopedValueBindings() {
206 set_scopedValueCache(nullptr);
207 oop vthread_oop = vthread();
208 // vthread may be null here if we get a VM error during startup,
209 // before the java.lang.Thread instance has been created.
210 if (vthread_oop != nullptr) {
211 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
212 }
213 }
214
215 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
216 bool daemon, TRAPS) {
217 assert(thread_group.not_null(), "thread group should be specified");
218 assert(threadObj() == nullptr, "should only create Java thread object once");
219
220 InstanceKlass* ik = vmClasses::Thread_klass();
221 assert(ik->is_initialized(), "must be");
222 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
223
224 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
225 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
226 // constructor calls Thread.current(), which must be set here.
227 java_lang_Thread::set_thread(thread_oop(), this);
228 set_threadOopHandles(thread_oop());
229
230 JavaValue result(T_VOID);
231 if (thread_name != nullptr) {
232 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
233 // Thread gets assigned specified name and null target
234 JavaCalls::call_special(&result,
235 thread_oop,
236 ik,
237 vmSymbols::object_initializer_name(),
238 vmSymbols::threadgroup_string_void_signature(),
239 thread_group,
240 name,
241 CHECK);
242 } else {
243 // Thread gets assigned name "Thread-nnn" and null target
244 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
245 JavaCalls::call_special(&result,
246 thread_oop,
247 ik,
248 vmSymbols::object_initializer_name(),
249 vmSymbols::threadgroup_runnable_void_signature(),
250 thread_group,
251 Handle(),
252 CHECK);
253 }
254 os::set_priority(this, NormPriority);
255
256 if (daemon) {
257 java_lang_Thread::set_daemon(thread_oop());
258 }
259 }
260
261 // ======= JavaThread ========
262
263 #if INCLUDE_JVMCI
264
265 jlong* JavaThread::_jvmci_old_thread_counters;
266
267 bool jvmci_counters_include(JavaThread* thread) {
268 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
269 }
270
271 void JavaThread::collect_counters(jlong* array, int length) {
272 assert(length == JVMCICounterSize, "wrong value");
273 for (int i = 0; i < length; i++) {
274 array[i] = _jvmci_old_thread_counters[i];
275 }
276 for (JavaThread* tp : ThreadsListHandle()) {
277 if (jvmci_counters_include(tp)) {
278 for (int i = 0; i < length; i++) {
279 array[i] += tp->_jvmci_counters[i];
280 }
281 }
282 }
283 }
284
285 // Attempt to enlarge the array for per thread counters.
286 jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
287 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
288 if (new_counters == nullptr) {
289 return nullptr;
290 }
291 if (old_counters == nullptr) {
292 old_counters = new_counters;
293 memset(old_counters, 0, sizeof(jlong) * new_size);
294 } else {
295 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
296 new_counters[i] = old_counters[i];
297 }
298 if (new_size > current_size) {
299 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
300 }
301 FREE_C_HEAP_ARRAY(jlong, old_counters);
302 }
303 return new_counters;
304 }
305
306 // Attempt to enlarge the array for per thread counters.
307 bool JavaThread::resize_counters(int current_size, int new_size) {
308 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
309 if (new_counters == nullptr) {
310 return false;
311 } else {
312 _jvmci_counters = new_counters;
313 return true;
314 }
315 }
316
317 class VM_JVMCIResizeCounters : public VM_Operation {
318 private:
319 int _new_size;
320 bool _failed;
321
322 public:
323 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
324 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
325 bool allow_nested_vm_operations() const { return true; }
326 void doit() {
327 // Resize the old thread counters array
328 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
329 if (new_counters == nullptr) {
330 _failed = true;
331 return;
332 } else {
333 JavaThread::_jvmci_old_thread_counters = new_counters;
334 }
335
336 // Now resize each threads array
337 for (JavaThread* tp : ThreadsListHandle()) {
338 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
339 _failed = true;
340 break;
341 }
342 }
343 if (!_failed) {
344 JVMCICounterSize = _new_size;
345 }
346 }
347
348 bool failed() { return _failed; }
349 };
350
351 bool JavaThread::resize_all_jvmci_counters(int new_size) {
352 VM_JVMCIResizeCounters op(new_size);
353 VMThread::execute(&op);
354 return !op.failed();
355 }
356
357 #endif // INCLUDE_JVMCI
358
359 #ifdef ASSERT
360 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
361 void JavaThread::check_possible_safepoint() {
362 if (_no_safepoint_count > 0) {
363 print_owned_locks();
364 assert(false, "Possible safepoint reached by thread that does not allow it");
365 }
366 #ifdef CHECK_UNHANDLED_OOPS
367 // Clear unhandled oops in JavaThreads so we get a crash right away.
368 clear_unhandled_oops();
369 #endif // CHECK_UNHANDLED_OOPS
370
371 // Macos/aarch64 should be in the right state for safepoint (e.g.
372 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
373 // happens in practice, making such issues hard to find and reproduce.
374 #if defined(__APPLE__) && defined(AARCH64)
375 if (AssertWXAtThreadSync) {
376 assert_wx_state(WXWrite);
377 }
378 #endif
379 }
380
381 void JavaThread::check_for_valid_safepoint_state() {
382 // Don't complain if running a debugging command.
383 if (DebuggingContext::is_enabled()) return;
384
385 // Check NoSafepointVerifier, which is implied by locks taken that can be
386 // shared with the VM thread. This makes sure that no locks with allow_vm_block
387 // are held.
388 check_possible_safepoint();
389
390 if (thread_state() != _thread_in_vm) {
391 fatal("LEAF method calling lock?");
392 }
393
394 if (GCALotAtAllSafepoints) {
395 // We could enter a safepoint here and thus have a gc
396 InterfaceSupport::check_gc_alot();
397 }
398 }
399 #endif // ASSERT
400
401 // A JavaThread is a normal Java thread
402
403 JavaThread::JavaThread() :
404 // Initialize fields
405
406 _on_thread_list(false),
407 DEBUG_ONLY(_java_call_counter(0) COMMA)
408 _entry_point(nullptr),
409 _deopt_mark(nullptr),
410 _deopt_nmethod(nullptr),
411 _vframe_array_head(nullptr),
412 _vframe_array_last(nullptr),
413 _jvmti_deferred_updates(nullptr),
414 _callee_target(nullptr),
415 _vm_result(nullptr),
416 _vm_result_2(nullptr),
417
418 _current_pending_monitor(nullptr),
419 _current_pending_monitor_is_from_java(true),
420 _current_waiting_monitor(nullptr),
421 _active_handles(nullptr),
422 _free_handle_block(nullptr),
423 _Stalled(0),
424
425 _monitor_chunks(nullptr),
426
427 _suspend_flags(0),
428
429 _thread_state(_thread_new),
430 _saved_exception_pc(nullptr),
431 #ifdef ASSERT
432 _no_safepoint_count(0),
433 _visited_for_critical_count(false),
434 #endif
435
436 _terminated(_not_terminated),
437 _in_deopt_handler(0),
438 _doing_unsafe_access(false),
439 _do_not_unlock_if_synchronized(false),
440 #if INCLUDE_JVMTI
441 _carrier_thread_suspended(false),
442 _is_in_VTMS_transition(false),
443 _is_in_tmp_VTMS_transition(false),
444 #ifdef ASSERT
445 _is_VTMS_transition_disabler(false),
446 #endif
447 #endif
448 _jni_attach_state(_not_attaching_via_jni),
449 #if INCLUDE_JVMCI
450 _pending_deoptimization(-1),
451 _pending_monitorenter(false),
452 _pending_transfer_to_interpreter(false),
453 _in_retryable_allocation(false),
454 _pending_failed_speculation(0),
455 _jvmci{nullptr},
456 _libjvmci_runtime(nullptr),
457 _jvmci_counters(nullptr),
458 _jvmci_reserved0(0),
459 _jvmci_reserved1(0),
460 _jvmci_reserved_oop0(nullptr),
461 #endif // INCLUDE_JVMCI
462
463 _exception_oop(oop()),
464 _exception_pc(0),
465 _exception_handler_pc(0),
466 _is_method_handle_return(0),
467
468 _jni_active_critical(0),
469 _pending_jni_exception_check_fn(nullptr),
470 _depth_first_number(0),
471
472 // JVMTI PopFrame support
473 _popframe_condition(popframe_inactive),
474 _frames_to_pop_failed_realloc(0),
475
476 _cont_entry(nullptr),
477 _cont_fastpath(0),
478 _cont_fastpath_thread_state(1),
479 _held_monitor_count(0),
480 _jni_monitor_count(0),
481
482 _handshake(this),
483
484 _popframe_preserved_args(nullptr),
485 _popframe_preserved_args_size(0),
486
487 _jvmti_thread_state(nullptr),
488 _interp_only_mode(0),
489 _should_post_on_exceptions_flag(JNI_FALSE),
490 _thread_stat(new ThreadStatistics()),
491
492 _parker(),
493
494 _class_to_be_initialized(nullptr),
495
496 _SleepEvent(ParkEvent::Allocate(this)),
497
498 _lock_stack(this) {
499 set_jni_functions(jni_functions());
500
501 #if INCLUDE_JVMCI
502 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
503 if (JVMCICounterSize > 0) {
504 resize_counters(0, (int) JVMCICounterSize);
505 }
506 #endif // INCLUDE_JVMCI
507
508 // Setup safepoint state info for this thread
509 ThreadSafepointState::create(this);
510
511 SafepointMechanism::initialize_header(this);
512
513 set_requires_cross_modify_fence(false);
514
515 pd_initialize();
516 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
517 }
518
519 JavaThread::JavaThread(bool is_attaching_via_jni) : JavaThread() {
520 if (is_attaching_via_jni) {
521 _jni_attach_state = _attaching_via_jni;
522 }
523 }
524
525
526 // interrupt support
527
528 void JavaThread::interrupt() {
529 // All callers should have 'this' thread protected by a
530 // ThreadsListHandle so that it cannot terminate and deallocate
531 // itself.
532 debug_only(check_for_dangling_thread_pointer(this);)
533
534 // For Windows _interrupt_event
535 WINDOWS_ONLY(osthread()->set_interrupted(true);)
536
537 // For Thread.sleep
538 _SleepEvent->unpark();
539
540 // For JSR166 LockSupport.park
541 parker()->unpark();
542
543 // For ObjectMonitor and JvmtiRawMonitor
544 _ParkEvent->unpark();
545 }
546
547
548 bool JavaThread::is_interrupted(bool clear_interrupted) {
549 debug_only(check_for_dangling_thread_pointer(this);)
550
551 if (_threadObj.peek() == nullptr) {
552 // If there is no j.l.Thread then it is impossible to have
553 // been interrupted. We can find null during VM initialization
554 // or when a JNI thread is still in the process of attaching.
555 // In such cases this must be the current thread.
556 assert(this == Thread::current(), "invariant");
557 return false;
558 }
559
560 bool interrupted = java_lang_Thread::interrupted(threadObj());
561
562 // NOTE that since there is no "lock" around the interrupt and
563 // is_interrupted operations, there is the possibility that the
564 // interrupted flag will be "false" but that the
565 // low-level events will be in the signaled state. This is
566 // intentional. The effect of this is that Object.wait() and
567 // LockSupport.park() will appear to have a spurious wakeup, which
568 // is allowed and not harmful, and the possibility is so rare that
569 // it is not worth the added complexity to add yet another lock.
570 // For the sleep event an explicit reset is performed on entry
571 // to JavaThread::sleep, so there is no early return. It has also been
572 // recommended not to put the interrupted flag into the "event"
573 // structure because it hides the issue.
574 // Also, because there is no lock, we must only clear the interrupt
575 // state if we are going to report that we were interrupted; otherwise
576 // an interrupt that happens just after we read the field would be lost.
577 if (interrupted && clear_interrupted) {
578 assert(this == Thread::current(), "only the current thread can clear");
579 java_lang_Thread::set_interrupted(threadObj(), false);
580 WINDOWS_ONLY(osthread()->set_interrupted(false);)
581 }
582
583 return interrupted;
584 }
585
586 void JavaThread::block_if_vm_exited() {
587 if (_terminated == _vm_exited) {
588 // _vm_exited is set at safepoint, and Threads_lock is never released
589 // so we will block here forever.
590 // Here we can be doing a jump from a safe state to an unsafe state without
591 // proper transition, but it happens after the final safepoint has begun so
592 // this jump won't cause any safepoint problems.
593 set_thread_state(_thread_in_vm);
594 Threads_lock->lock();
595 ShouldNotReachHere();
596 }
597 }
598
599 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) : JavaThread() {
600 _jni_attach_state = _not_attaching_via_jni;
601 set_entry_point(entry_point);
602 // Create the native thread itself.
603 // %note runtime_23
604 os::ThreadType thr_type = os::java_thread;
605 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
606 os::java_thread;
607 os::create_thread(this, thr_type, stack_sz);
608 // The _osthread may be null here because we ran out of memory (too many threads active).
609 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
610 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
611 // the exception consists of creating the exception object & initializing it, initialization
612 // will leave the VM via a JavaCall and then all locks must be unlocked).
613 //
614 // The thread is still suspended when we reach here. Thread must be explicit started
615 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
616 // by calling Threads:add. The reason why this is not done here, is because the thread
617 // object must be fully initialized (take a look at JVM_Start)
618 }
619
620 JavaThread::~JavaThread() {
621
622 // Enqueue OopHandles for release by the service thread.
623 add_oop_handles_for_release();
624
625 // Return the sleep event to the free list
626 ParkEvent::Release(_SleepEvent);
627 _SleepEvent = nullptr;
628
629 // Free any remaining previous UnrollBlock
630 vframeArray* old_array = vframe_array_last();
631
632 if (old_array != nullptr) {
633 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
634 old_array->set_unroll_block(nullptr);
635 delete old_info;
636 delete old_array;
637 }
638
639 JvmtiDeferredUpdates* updates = deferred_updates();
640 if (updates != nullptr) {
641 // This can only happen if thread is destroyed before deoptimization occurs.
642 assert(updates->count() > 0, "Updates holder not deleted");
643 // free deferred updates.
644 delete updates;
645 set_deferred_updates(nullptr);
646 }
647
648 // All Java related clean up happens in exit
649 ThreadSafepointState::destroy(this);
650 if (_thread_stat != nullptr) delete _thread_stat;
651
652 #if INCLUDE_JVMCI
653 if (JVMCICounterSize > 0) {
654 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
655 }
656 #endif // INCLUDE_JVMCI
657 }
658
659
660 // First JavaThread specific code executed by a new Java thread.
661 void JavaThread::pre_run() {
662 // empty - see comments in run()
663 }
664
665 // The main routine called by a new Java thread. This isn't overridden
666 // by subclasses, instead different subclasses define a different "entry_point"
667 // which defines the actual logic for that kind of thread.
668 void JavaThread::run() {
669 // initialize thread-local alloc buffer related fields
670 initialize_tlab();
671
672 _stack_overflow_state.create_stack_guard_pages();
673
674 cache_global_variables();
675
676 // Thread is now sufficiently initialized to be handled by the safepoint code as being
677 // in the VM. Change thread state from _thread_new to _thread_in_vm
678 assert(this->thread_state() == _thread_new, "wrong thread state");
679 set_thread_state(_thread_in_vm);
680
681 // Before a thread is on the threads list it is always safe, so after leaving the
682 // _thread_new we should emit a instruction barrier. The distance to modified code
683 // from here is probably far enough, but this is consistent and safe.
684 OrderAccess::cross_modify_fence();
685
686 assert(JavaThread::current() == this, "sanity check");
687 assert(!Thread::current()->owns_locks(), "sanity check");
688
689 DTRACE_THREAD_PROBE(start, this);
690
691 // This operation might block. We call that after all safepoint checks for a new thread has
692 // been completed.
693 set_active_handles(JNIHandleBlock::allocate_block());
694
695 if (JvmtiExport::should_post_thread_life()) {
696 JvmtiExport::post_thread_start(this);
697
698 }
699
700 if (AlwaysPreTouchStacks) {
701 pretouch_stack();
702 }
703
704 // We call another function to do the rest so we are sure that the stack addresses used
705 // from there will be lower than the stack base just computed.
706 thread_main_inner();
707 }
708
709 void JavaThread::thread_main_inner() {
710 assert(JavaThread::current() == this, "sanity check");
711 assert(_threadObj.peek() != nullptr, "just checking");
712
713 // Execute thread entry point unless this thread has a pending exception.
714 // Note: Due to JVMTI StopThread we can have pending exceptions already!
715 if (!this->has_pending_exception()) {
716 {
717 ResourceMark rm(this);
718 this->set_native_thread_name(this->name());
719 }
720 HandleMark hm(this);
721 this->entry_point()(this, this);
722 }
723
724 DTRACE_THREAD_PROBE(stop, this);
725
726 // Cleanup is handled in post_run()
727 }
728
729 // Shared teardown for all JavaThreads
730 void JavaThread::post_run() {
731 this->exit(false);
732 this->unregister_thread_stack_with_NMT();
733 // Defer deletion to here to ensure 'this' is still referenceable in call_run
734 // for any shared tear-down.
735 this->smr_delete();
736 }
737
738 static void ensure_join(JavaThread* thread) {
739 // We do not need to grab the Threads_lock, since we are operating on ourself.
740 Handle threadObj(thread, thread->threadObj());
741 assert(threadObj.not_null(), "java thread object must exist");
742 ObjectLocker lock(threadObj, thread);
743 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
744 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
745 // Clear the native thread instance - this makes isAlive return false and allows the join()
746 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
747 // requirements.
748 java_lang_Thread::release_set_thread(threadObj(), nullptr);
749 lock.notify_all(thread);
750 // Ignore pending exception, since we are exiting anyway
751 thread->clear_pending_exception();
752 }
753
754 static bool is_daemon(oop threadObj) {
755 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
756 }
757
758 // For any new cleanup additions, please check to see if they need to be applied to
759 // cleanup_failed_attach_current_thread as well.
760 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
761 assert(this == JavaThread::current(), "thread consistency check");
762 assert(!is_exiting(), "should not be exiting or terminated already");
763
764 elapsedTimer _timer_exit_phase1;
765 elapsedTimer _timer_exit_phase2;
766 elapsedTimer _timer_exit_phase3;
767 elapsedTimer _timer_exit_phase4;
768
769 if (log_is_enabled(Debug, os, thread, timer)) {
770 _timer_exit_phase1.start();
771 }
772
773 HandleMark hm(this);
774 Handle uncaught_exception(this, this->pending_exception());
775 this->clear_pending_exception();
776 Handle threadObj(this, this->threadObj());
777 assert(threadObj.not_null(), "Java thread object should be created");
778
779 if (!destroy_vm) {
780 if (uncaught_exception.not_null()) {
781 EXCEPTION_MARK;
782 // Call method Thread.dispatchUncaughtException().
783 Klass* thread_klass = vmClasses::Thread_klass();
784 JavaValue result(T_VOID);
785 JavaCalls::call_virtual(&result,
786 threadObj, thread_klass,
787 vmSymbols::dispatchUncaughtException_name(),
788 vmSymbols::throwable_void_signature(),
789 uncaught_exception,
790 THREAD);
791 if (HAS_PENDING_EXCEPTION) {
792 ResourceMark rm(this);
793 jio_fprintf(defaultStream::error_stream(),
794 "\nException: %s thrown from the UncaughtExceptionHandler"
795 " in thread \"%s\"\n",
796 pending_exception()->klass()->external_name(),
797 name());
798 CLEAR_PENDING_EXCEPTION;
799 }
800 }
801
802 if (!is_Compiler_thread()) {
803 // We have finished executing user-defined Java code and now have to do the
804 // implementation specific clean-up by calling Thread.exit(). We prevent any
805 // asynchronous exceptions from being delivered while in Thread.exit()
806 // to ensure the clean-up is not corrupted.
807 NoAsyncExceptionDeliveryMark _no_async(this);
808
809 EXCEPTION_MARK;
810 JavaValue result(T_VOID);
811 Klass* thread_klass = vmClasses::Thread_klass();
812 JavaCalls::call_virtual(&result,
813 threadObj, thread_klass,
814 vmSymbols::exit_method_name(),
815 vmSymbols::void_method_signature(),
816 THREAD);
817 CLEAR_PENDING_EXCEPTION;
818 }
819
820 // notify JVMTI
821 if (JvmtiExport::should_post_thread_life()) {
822 JvmtiExport::post_thread_end(this);
823 }
824 } else {
825 // before_exit() has already posted JVMTI THREAD_END events
826 }
827
828 // Cleanup any pending async exception now since we cannot access oops after
829 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
830 if (has_async_exception_condition()) {
831 handshake_state()->clean_async_exception_operation();
832 }
833
834 // The careful dance between thread suspension and exit is handled here.
835 // Since we are in thread_in_vm state and suspension is done with handshakes,
836 // we can just put in the exiting state and it will be correctly handled.
837 // Also, no more async exceptions will be added to the queue after this point.
838 set_terminated(_thread_exiting);
839 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
840
841 if (log_is_enabled(Debug, os, thread, timer)) {
842 _timer_exit_phase1.stop();
843 _timer_exit_phase2.start();
844 }
845
846 // Capture daemon status before the thread is marked as terminated.
847 bool daemon = is_daemon(threadObj());
848
849 // Notify waiters on thread object. This has to be done after exit() is called
850 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
851 // group should have the destroyed bit set before waiters are notified).
852 ensure_join(this);
853 assert(!this->has_pending_exception(), "ensure_join should have cleared");
854
855 if (log_is_enabled(Debug, os, thread, timer)) {
856 _timer_exit_phase2.stop();
857 _timer_exit_phase3.start();
858 }
859 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
860 // held by this thread must be released. The spec does not distinguish
861 // between JNI-acquired and regular Java monitors. We can only see
862 // regular Java monitors here if monitor enter-exit matching is broken.
863 //
864 // ensure_join() ignores IllegalThreadStateExceptions, and so does
865 // ObjectSynchronizer::release_monitors_owned_by_thread().
866 if (exit_type == jni_detach) {
867 // Sanity check even though JNI DetachCurrentThread() would have
868 // returned JNI_ERR if there was a Java frame. JavaThread exit
869 // should be done executing Java code by the time we get here.
870 assert(!this->has_last_Java_frame(),
871 "should not have a Java frame when detaching or exiting");
872 ObjectSynchronizer::release_monitors_owned_by_thread(this);
873 assert(!this->has_pending_exception(), "release_monitors should have cleared");
874 }
875
876 // Since above code may not release JNI monitors and if someone forgot to do an
877 // JNI monitorexit, held count should be equal jni count.
878 // Consider scan all object monitor for this owner if JNI count > 0 (at least on detach).
879 assert(this->held_monitor_count() == this->jni_monitor_count(),
880 "held monitor count should be equal to jni: " INT64_FORMAT " != " INT64_FORMAT,
881 (int64_t)this->held_monitor_count(), (int64_t)this->jni_monitor_count());
882 if (CheckJNICalls && this->jni_monitor_count() > 0) {
883 // We would like a fatal here, but due to we never checked this before there
884 // is a lot of tests which breaks, even with an error log.
885 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
886 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
887 }
888
889 // These things needs to be done while we are still a Java Thread. Make sure that thread
890 // is in a consistent state, in case GC happens
891 JFR_ONLY(Jfr::on_thread_exit(this);)
892
893 if (active_handles() != nullptr) {
894 JNIHandleBlock* block = active_handles();
895 set_active_handles(nullptr);
896 JNIHandleBlock::release_block(block);
897 }
898
899 if (free_handle_block() != nullptr) {
900 JNIHandleBlock* block = free_handle_block();
901 set_free_handle_block(nullptr);
902 JNIHandleBlock::release_block(block);
903 }
904
905 // These have to be removed while this is still a valid thread.
906 _stack_overflow_state.remove_stack_guard_pages();
907
908 if (UseTLAB) {
909 tlab().retire();
910 }
911
912 if (JvmtiEnv::environments_might_exist()) {
913 JvmtiExport::cleanup_thread(this);
914 }
915
916 // We need to cache the thread name for logging purposes below as once
917 // we have called on_thread_detach this thread must not access any oops.
918 char* thread_name = nullptr;
919 if (log_is_enabled(Debug, os, thread, timer)) {
920 ResourceMark rm(this);
921 thread_name = os::strdup(name());
922 }
923
924 log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
925 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
926 os::current_thread_id());
927
928 if (log_is_enabled(Debug, os, thread, timer)) {
929 _timer_exit_phase3.stop();
930 _timer_exit_phase4.start();
931 }
932
933 #if INCLUDE_JVMCI
934 if (JVMCICounterSize > 0) {
935 if (jvmci_counters_include(this)) {
936 for (int i = 0; i < JVMCICounterSize; i++) {
937 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
938 }
939 }
940 }
941 #endif // INCLUDE_JVMCI
942
943 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
944 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
945 Threads::remove(this, daemon);
946
947 if (log_is_enabled(Debug, os, thread, timer)) {
948 _timer_exit_phase4.stop();
949 log_debug(os, thread, timer)("name='%s'"
950 ", exit-phase1=" JLONG_FORMAT
951 ", exit-phase2=" JLONG_FORMAT
952 ", exit-phase3=" JLONG_FORMAT
953 ", exit-phase4=" JLONG_FORMAT,
954 thread_name,
955 _timer_exit_phase1.milliseconds(),
956 _timer_exit_phase2.milliseconds(),
957 _timer_exit_phase3.milliseconds(),
958 _timer_exit_phase4.milliseconds());
959 os::free(thread_name);
960 }
961 }
962
963 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
964 if (active_handles() != nullptr) {
965 JNIHandleBlock* block = active_handles();
966 set_active_handles(nullptr);
967 JNIHandleBlock::release_block(block);
968 }
969
970 if (free_handle_block() != nullptr) {
971 JNIHandleBlock* block = free_handle_block();
972 set_free_handle_block(nullptr);
973 JNIHandleBlock::release_block(block);
974 }
975
976 // These have to be removed while this is still a valid thread.
977 _stack_overflow_state.remove_stack_guard_pages();
978
979 if (UseTLAB) {
980 tlab().retire();
981 }
982
983 Threads::remove(this, is_daemon);
984 this->smr_delete();
985 }
986
987 JavaThread* JavaThread::active() {
988 Thread* thread = Thread::current();
989 if (thread->is_Java_thread()) {
990 return JavaThread::cast(thread);
991 } else {
992 assert(thread->is_VM_thread(), "this must be a vm thread");
993 VM_Operation* op = ((VMThread*) thread)->vm_operation();
994 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
995 return ret;
996 }
997 }
998
999 bool JavaThread::is_lock_owned(address adr) const {
1000 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1001 if (Thread::is_lock_owned(adr)) return true;
1002
1003 for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
1004 if (chunk->contains(adr)) return true;
1005 }
1006
1007 return false;
1008 }
1009
1010 oop JavaThread::exception_oop() const {
1011 return Atomic::load(&_exception_oop);
1012 }
1013
1014 void JavaThread::set_exception_oop(oop o) {
1015 Atomic::store(&_exception_oop, o);
1016 }
1017
1018 void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
1019 chunk->set_next(monitor_chunks());
1020 set_monitor_chunks(chunk);
1021 }
1022
1023 void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
1024 guarantee(monitor_chunks() != nullptr, "must be non empty");
1025 if (monitor_chunks() == chunk) {
1026 set_monitor_chunks(chunk->next());
1027 } else {
1028 MonitorChunk* prev = monitor_chunks();
1029 while (prev->next() != chunk) prev = prev->next();
1030 prev->set_next(chunk->next());
1031 }
1032 }
1033
1034 void JavaThread::handle_special_runtime_exit_condition() {
1035 if (is_obj_deopt_suspend()) {
1036 frame_anchor()->make_walkable();
1037 wait_for_object_deoptimization();
1038 }
1039 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1040 }
1041
1042
1043 // Asynchronous exceptions support
1044 //
1045 void JavaThread::handle_async_exception(oop java_throwable) {
1046 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1047 assert(!is_at_poll_safepoint(), "should have never called this method");
1048
1049 if (has_last_Java_frame()) {
1050 frame f = last_frame();
1051 if (f.is_runtime_frame()) {
1052 // If the topmost frame is a runtime stub, then we are calling into
1053 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1054 // must deoptimize the caller before continuing, as the compiled exception
1055 // handler table may not be valid.
1056 RegisterMap reg_map(this,
1057 RegisterMap::UpdateMap::skip,
1058 RegisterMap::ProcessFrames::include,
1059 RegisterMap::WalkContinuation::skip);
1060 frame compiled_frame = f.sender(®_map);
1061 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1062 Deoptimization::deoptimize(this, compiled_frame);
1063 }
1064 }
1065 }
1066
1067 // We cannot call Exceptions::_throw(...) here because we cannot block
1068 set_pending_exception(java_throwable, __FILE__, __LINE__);
1069
1070 clear_scopedValueBindings();
1071
1072 LogTarget(Info, exceptions) lt;
1073 if (lt.is_enabled()) {
1074 ResourceMark rm;
1075 LogStream ls(lt);
1076 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1077 if (has_last_Java_frame()) {
1078 frame f = last_frame();
1079 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1080 }
1081 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1082 }
1083 }
1084
1085 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1086 // Do not throw asynchronous exceptions against the compiler thread
1087 // or if the thread is already exiting.
1088 if (!can_call_java() || is_exiting()) {
1089 delete aeh;
1090 return;
1091 }
1092
1093 oop exception = aeh->exception();
1094 Handshake::execute(aeh, this); // Install asynchronous handshake
1095
1096 ResourceMark rm;
1097 if (log_is_enabled(Info, exceptions)) {
1098 log_info(exceptions)("Pending Async. exception installed of type: %s",
1099 InstanceKlass::cast(exception->klass())->external_name());
1100 }
1101 // for AbortVMOnException flag
1102 Exceptions::debug_check_abort(exception->klass()->external_name());
1103
1104 oop vt_oop = vthread();
1105 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1106 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1107 java_lang_Thread::set_interrupted(threadObj(), true);
1108 this->interrupt();
1109 }
1110 }
1111
1112 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1113 AsyncExceptionHandshake* _aeh;
1114 public:
1115 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1116 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1117 ~InstallAsyncExceptionHandshake() {
1118 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1119 delete _aeh;
1120 }
1121 void do_thread(Thread* thr) {
1122 JavaThread* target = JavaThread::cast(thr);
1123 target->install_async_exception(_aeh);
1124 _aeh = nullptr;
1125 }
1126 };
1127
1128 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1129 OopHandle e(Universe::vm_global(), java_throwable);
1130 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1131 Handshake::execute(&iaeh, target);
1132 }
1133
1134 #if INCLUDE_JVMTI
1135 void JavaThread::set_is_in_VTMS_transition(bool val) {
1136 _is_in_VTMS_transition = val;
1137 }
1138
1139 #ifdef ASSERT
1140 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1141 _is_VTMS_transition_disabler = val;
1142 }
1143 #endif
1144 #endif
1145
1146 // External suspension mechanism.
1147 //
1148 // Guarantees on return (for a valid target thread):
1149 // - Target thread will not execute any new bytecode.
1150 // - Target thread will not enter any new monitors.
1151 //
1152 bool JavaThread::java_suspend() {
1153 #if INCLUDE_JVMTI
1154 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1155 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1156 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1157 #endif
1158
1159 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1160 "target JavaThread is not protected in calling context.");
1161 return this->handshake_state()->suspend();
1162 }
1163
1164 bool JavaThread::java_resume() {
1165 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1166 "missing ThreadsListHandle in calling context.");
1167 return this->handshake_state()->resume();
1168 }
1169
1170 // Wait for another thread to perform object reallocation and relocking on behalf of
1171 // this thread. The current thread is required to change to _thread_blocked in order
1172 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1173 // handshake safe, the other thread can complete the handshake used to synchronize
1174 // with this thread and then perform the reallocation and relocking.
1175 // See EscapeBarrier::sync_and_suspend_*()
1176
1177 void JavaThread::wait_for_object_deoptimization() {
1178 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1179 assert(this == Thread::current(), "invariant");
1180
1181 bool spin_wait = os::is_MP();
1182 do {
1183 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1184 // Wait for object deoptimization if requested.
1185 if (spin_wait) {
1186 // A single deoptimization is typically very short. Microbenchmarks
1187 // showed 5% better performance when spinning.
1188 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1189 SpinYield spin(spin_limit);
1190 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1191 spin.wait();
1192 }
1193 // Spin just once
1194 spin_wait = false;
1195 } else {
1196 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1197 if (is_obj_deopt_suspend()) {
1198 ml.wait();
1199 }
1200 }
1201 // A handshake for obj. deoptimization suspend could have been processed so
1202 // we must check after processing.
1203 } while (is_obj_deopt_suspend());
1204 }
1205
1206 #ifdef ASSERT
1207 // Verify the JavaThread has not yet been published in the Threads::list, and
1208 // hence doesn't need protection from concurrent access at this stage.
1209 void JavaThread::verify_not_published() {
1210 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1211 // since an unpublished JavaThread doesn't participate in the
1212 // Thread-SMR protocol for keeping a ThreadsList alive.
1213 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1214 }
1215 #endif
1216
1217 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1218 // pending, when _suspend_flags is non-zero or when we need to process a stack
1219 // watermark. Also check for pending async exceptions (except unsafe access error).
1220 // Note only the native==>Java barriers can call this function when thread state
1221 // is _thread_in_native_trans.
1222 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1223 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1224 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1225
1226 thread->set_thread_state(_thread_in_vm);
1227
1228 // Enable WXWrite: called directly from interpreter native wrapper.
1229 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1230
1231 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1232
1233 // After returning from native, it could be that the stack frames are not
1234 // yet safe to use. We catch such situations in the subsequent stack watermark
1235 // barrier, which will trap unsafe stack frames.
1236 StackWatermarkSet::before_unwind(thread);
1237 }
1238
1239 #ifndef PRODUCT
1240 // Deoptimization
1241 // Function for testing deoptimization
1242 void JavaThread::deoptimize() {
1243 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1244 bool deopt = false; // Dump stack only if a deopt actually happens.
1245 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1246 // Iterate over all frames in the thread and deoptimize
1247 for (; !fst.is_done(); fst.next()) {
1248 if (fst.current()->can_be_deoptimized()) {
1249
1250 if (only_at) {
1251 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1252 // consists of comma or carriage return separated numbers so
1253 // search for the current bci in that string.
1254 address pc = fst.current()->pc();
1255 nmethod* nm = (nmethod*) fst.current()->cb();
1256 ScopeDesc* sd = nm->scope_desc_at(pc);
1257 char buffer[8];
1258 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1259 size_t len = strlen(buffer);
1260 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1261 while (found != nullptr) {
1262 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1263 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1264 // Check that the bci found is bracketed by terminators.
1265 break;
1266 }
1267 found = strstr(found + 1, buffer);
1268 }
1269 if (!found) {
1270 continue;
1271 }
1272 }
1273
1274 if (DebugDeoptimization && !deopt) {
1275 deopt = true; // One-time only print before deopt
1276 tty->print_cr("[BEFORE Deoptimization]");
1277 trace_frames();
1278 trace_stack();
1279 }
1280 Deoptimization::deoptimize(this, *fst.current());
1281 }
1282 }
1283
1284 if (DebugDeoptimization && deopt) {
1285 tty->print_cr("[AFTER Deoptimization]");
1286 trace_frames();
1287 }
1288 }
1289
1290
1291 // Make zombies
1292 void JavaThread::make_zombies() {
1293 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1294 if (fst.current()->can_be_deoptimized()) {
1295 // it is a Java nmethod
1296 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1297 nm->make_not_entrant();
1298 }
1299 }
1300 }
1301 #endif // PRODUCT
1302
1303
1304 void JavaThread::deoptimize_marked_methods() {
1305 if (!has_last_Java_frame()) return;
1306 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1307 for (; !fst.is_done(); fst.next()) {
1308 if (fst.current()->should_be_deoptimized()) {
1309 Deoptimization::deoptimize(this, *fst.current());
1310 }
1311 }
1312 }
1313
1314 #ifdef ASSERT
1315 void JavaThread::verify_frame_info() {
1316 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1317 (has_last_Java_frame() && java_call_counter() > 0),
1318 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1319 has_last_Java_frame() ? "true" : "false", java_call_counter());
1320 }
1321 #endif
1322
1323 // Push on a new block of JNI handles.
1324 void JavaThread::push_jni_handle_block() {
1325 // Allocate a new block for JNI handles.
1326 // Inlined code from jni_PushLocalFrame()
1327 JNIHandleBlock* old_handles = active_handles();
1328 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1329 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1330 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1331 set_active_handles(new_handles);
1332 }
1333
1334 // Pop off the current block of JNI handles.
1335 void JavaThread::pop_jni_handle_block() {
1336 // Release our JNI handle block
1337 JNIHandleBlock* old_handles = active_handles();
1338 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1339 assert(new_handles != nullptr, "should never set active handles to null");
1340 set_active_handles(new_handles);
1341 old_handles->set_pop_frame_link(nullptr);
1342 JNIHandleBlock::release_block(old_handles, this);
1343 }
1344
1345 void JavaThread::oops_do_no_frames(OopClosure* f, CodeBlobClosure* cf) {
1346 // Verify that the deferred card marks have been flushed.
1347 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1348
1349 // Traverse the GCHandles
1350 Thread::oops_do_no_frames(f, cf);
1351
1352 if (active_handles() != nullptr) {
1353 active_handles()->oops_do(f);
1354 }
1355
1356 DEBUG_ONLY(verify_frame_info();)
1357
1358 if (has_last_Java_frame()) {
1359 // Traverse the monitor chunks
1360 for (MonitorChunk* chunk = monitor_chunks(); chunk != nullptr; chunk = chunk->next()) {
1361 chunk->oops_do(f);
1362 }
1363 }
1364
1365 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1366 // If we have deferred set_locals there might be oops waiting to be
1367 // written
1368 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1369 if (list != nullptr) {
1370 for (int i = 0; i < list->length(); i++) {
1371 list->at(i)->oops_do(f);
1372 }
1373 }
1374
1375 // Traverse instance variables at the end since the GC may be moving things
1376 // around using this function
1377 f->do_oop((oop*) &_vm_result);
1378 f->do_oop((oop*) &_exception_oop);
1379 #if INCLUDE_JVMCI
1380 f->do_oop((oop*) &_jvmci_reserved_oop0);
1381 #endif
1382
1383 if (jvmti_thread_state() != nullptr) {
1384 jvmti_thread_state()->oops_do(f, cf);
1385 }
1386
1387 // The continuation oops are really on the stack. But there is typically at most
1388 // one of those per thread, so we handle them here in the oops_do_no_frames part
1389 // so that we don't have to sprinkle as many stack watermark checks where these
1390 // oops are used. We just need to make sure the thread has started processing.
1391 ContinuationEntry* entry = _cont_entry;
1392 while (entry != nullptr) {
1393 f->do_oop((oop*)entry->cont_addr());
1394 f->do_oop((oop*)entry->chunk_addr());
1395 entry = entry->parent();
1396 }
1397
1398 if (LockingMode == LM_LIGHTWEIGHT) {
1399 lock_stack().oops_do(f);
1400 }
1401 }
1402
1403 void JavaThread::oops_do_frames(OopClosure* f, CodeBlobClosure* cf) {
1404 if (!has_last_Java_frame()) {
1405 return;
1406 }
1407 // Finish any pending lazy GC activity for the frames
1408 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1409 // Traverse the execution stack
1410 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1411 fst.current()->oops_do(f, cf, fst.register_map());
1412 }
1413 }
1414
1415 #ifdef ASSERT
1416 void JavaThread::verify_states_for_handshake() {
1417 // This checks that the thread has a correct frame state during a handshake.
1418 verify_frame_info();
1419 }
1420 #endif
1421
1422 void JavaThread::nmethods_do(CodeBlobClosure* cf) {
1423 DEBUG_ONLY(verify_frame_info();)
1424 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1425
1426 if (has_last_Java_frame()) {
1427 // Traverse the execution stack
1428 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1429 fst.current()->nmethods_do(cf);
1430 }
1431 }
1432
1433 if (jvmti_thread_state() != nullptr) {
1434 jvmti_thread_state()->nmethods_do(cf);
1435 }
1436 }
1437
1438 void JavaThread::metadata_do(MetadataClosure* f) {
1439 if (has_last_Java_frame()) {
1440 // Traverse the execution stack to call f() on the methods in the stack
1441 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1442 fst.current()->metadata_do(f);
1443 }
1444 } else if (is_Compiler_thread()) {
1445 // need to walk ciMetadata in current compile tasks to keep alive.
1446 CompilerThread* ct = (CompilerThread*)this;
1447 if (ct->env() != nullptr) {
1448 ct->env()->metadata_do(f);
1449 }
1450 CompileTask* task = ct->task();
1451 if (task != nullptr) {
1452 task->metadata_do(f);
1453 }
1454 }
1455 }
1456
1457 // Printing
1458 const char* _get_thread_state_name(JavaThreadState _thread_state) {
1459 switch (_thread_state) {
1460 case _thread_uninitialized: return "_thread_uninitialized";
1461 case _thread_new: return "_thread_new";
1462 case _thread_new_trans: return "_thread_new_trans";
1463 case _thread_in_native: return "_thread_in_native";
1464 case _thread_in_native_trans: return "_thread_in_native_trans";
1465 case _thread_in_vm: return "_thread_in_vm";
1466 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1467 case _thread_in_Java: return "_thread_in_Java";
1468 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1469 case _thread_blocked: return "_thread_blocked";
1470 case _thread_blocked_trans: return "_thread_blocked_trans";
1471 default: return "unknown thread state";
1472 }
1473 }
1474
1475 void JavaThread::print_thread_state_on(outputStream *st) const {
1476 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1477 }
1478
1479 // Called by Threads::print() for VM_PrintThreads operation
1480 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1481 st->print_raw("\"");
1482 st->print_raw(name());
1483 st->print_raw("\" ");
1484 oop thread_oop = threadObj();
1485 if (thread_oop != nullptr) {
1486 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1487 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1488 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1489 }
1490 Thread::print_on(st, print_extended_info);
1491 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1492 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1493 if (thread_oop != nullptr) {
1494 if (is_vthread_mounted()) {
1495 oop vt = vthread();
1496 assert(vt != nullptr, "");
1497 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1498 } else {
1499 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1500 }
1501 }
1502 #ifndef PRODUCT
1503 _safepoint_state->print_on(st);
1504 #endif // PRODUCT
1505 if (is_Compiler_thread()) {
1506 CompileTask *task = ((CompilerThread*)this)->task();
1507 if (task != nullptr) {
1508 st->print(" Compiling: ");
1509 task->print(st, nullptr, true, false);
1510 } else {
1511 st->print(" No compile task");
1512 }
1513 st->cr();
1514 }
1515 }
1516
1517 void JavaThread::print() const { print_on(tty); }
1518
1519 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1520 st->print("%s", get_thread_name_string(buf, buflen));
1521 }
1522
1523 // Called by fatal error handler. The difference between this and
1524 // JavaThread::print() is that we can't grab lock or allocate memory.
1525 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1526 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1527 Thread* current = Thread::current_or_null_safe();
1528 assert(current != nullptr, "cannot be called by a detached thread");
1529 st->fill_to(60);
1530 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1531 // Only access threadObj() if current thread is not a JavaThread
1532 // or if it is a JavaThread that can safely access oops.
1533 oop thread_obj = threadObj();
1534 if (thread_obj != nullptr) {
1535 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1536 }
1537 }
1538 st->print(" [");
1539 st->print("%s", _get_thread_state_name(_thread_state));
1540 if (osthread()) {
1541 st->print(", id=%d", osthread()->thread_id());
1542 }
1543 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1544 p2i(stack_end()), p2i(stack_base()),
1545 PROPERFMTARGS(stack_size()));
1546 st->print("]");
1547
1548 ThreadsSMRSupport::print_info_on(this, st);
1549 return;
1550 }
1551
1552
1553 // Verification
1554
1555 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1556 // ignore if there is no stack
1557 if (!has_last_Java_frame()) return;
1558 // traverse the stack frames. Starts from top frame.
1559 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1560 frame* fr = fst.current();
1561 f(fr, fst.register_map());
1562 }
1563 }
1564
1565 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1566
1567 void JavaThread::verify() {
1568 // Verify oops in the thread.
1569 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1570
1571 // Verify the stack frames.
1572 frames_do(frame_verify);
1573 }
1574
1575 // CR 6300358 (sub-CR 2137150)
1576 // Most callers of this method assume that it can't return null but a
1577 // thread may not have a name whilst it is in the process of attaching to
1578 // the VM - see CR 6412693, and there are places where a JavaThread can be
1579 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1580 // if vm exit occurs during initialization). These cases can all be accounted
1581 // for such that this method never returns null.
1582 const char* JavaThread::name() const {
1583 if (Thread::is_JavaThread_protected(/* target */ this)) {
1584 // The target JavaThread is protected so get_thread_name_string() is safe:
1585 return get_thread_name_string();
1586 }
1587
1588 // The target JavaThread is not protected so we return the default:
1589 return Thread::name();
1590 }
1591
1592 // Returns a non-null representation of this thread's name, or a suitable
1593 // descriptive string if there is no set name.
1594 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1595 const char* name_str;
1596 #ifdef ASSERT
1597 Thread* current = Thread::current_or_null_safe();
1598 assert(current != nullptr, "cannot be called by a detached thread");
1599 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1600 // Only access threadObj() if current thread is not a JavaThread
1601 // or if it is a JavaThread that can safely access oops.
1602 #endif
1603 oop thread_obj = threadObj();
1604 if (thread_obj != nullptr) {
1605 oop name = java_lang_Thread::name(thread_obj);
1606 if (name != nullptr) {
1607 if (buf == nullptr) {
1608 name_str = java_lang_String::as_utf8_string(name);
1609 } else {
1610 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1611 }
1612 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1613 name_str = "<no-name - thread is attaching>";
1614 } else {
1615 name_str = "<un-named>";
1616 }
1617 } else {
1618 name_str = Thread::name();
1619 }
1620 #ifdef ASSERT
1621 } else {
1622 // Current JavaThread has exited...
1623 if (current == this) {
1624 // ... and is asking about itself:
1625 name_str = "<no-name - current JavaThread has exited>";
1626 } else {
1627 // ... and it can't safely determine this JavaThread's name so
1628 // use the default thread name.
1629 name_str = Thread::name();
1630 }
1631 }
1632 #endif
1633 assert(name_str != nullptr, "unexpected null thread name");
1634 return name_str;
1635 }
1636
1637 // Helper to extract the name from the thread oop for logging.
1638 const char* JavaThread::name_for(oop thread_obj) {
1639 assert(thread_obj != nullptr, "precondition");
1640 oop name = java_lang_Thread::name(thread_obj);
1641 const char* name_str;
1642 if (name != nullptr) {
1643 name_str = java_lang_String::as_utf8_string(name);
1644 } else {
1645 name_str = "<un-named>";
1646 }
1647 return name_str;
1648 }
1649
1650 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1651
1652 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1653 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1654 // Link Java Thread object <-> C++ Thread
1655
1656 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1657 // and put it into a new Handle. The Handle "thread_oop" can then
1658 // be used to pass the C++ thread object to other methods.
1659
1660 // Set the Java level thread object (jthread) field of the
1661 // new thread (a JavaThread *) to C++ thread object using the
1662 // "thread_oop" handle.
1663
1664 // Set the thread field (a JavaThread *) of the
1665 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1666
1667 Handle thread_oop(Thread::current(),
1668 JNIHandles::resolve_non_null(jni_thread));
1669 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1670 "must be initialized");
1671 set_threadOopHandles(thread_oop());
1672
1673 if (prio == NoPriority) {
1674 prio = java_lang_Thread::priority(thread_oop());
1675 assert(prio != NoPriority, "A valid priority should be present");
1676 }
1677
1678 // Push the Java priority down to the native thread; needs Threads_lock
1679 Thread::set_priority(this, prio);
1680
1681 // Add the new thread to the Threads list and set it in motion.
1682 // We must have threads lock in order to call Threads::add.
1683 // It is crucial that we do not block before the thread is
1684 // added to the Threads list for if a GC happens, then the java_thread oop
1685 // will not be visited by GC.
1686 Threads::add(this);
1687 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1688 // on a ThreadsList. We don't want to wait for the release when the
1689 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1690 // is already visible to JVM/TI via the ThreadsList.
1691 java_lang_Thread::release_set_thread(thread_oop(), this);
1692 }
1693
1694 oop JavaThread::current_park_blocker() {
1695 // Support for JSR-166 locks
1696 oop thread_oop = threadObj();
1697 if (thread_oop != nullptr) {
1698 return java_lang_Thread::park_blocker(thread_oop);
1699 }
1700 return nullptr;
1701 }
1702
1703 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1704 // This is the external format, selecting the platform or vthread
1705 // as applicable, and allowing for a native-only stack.
1706 void JavaThread::print_jni_stack() {
1707 assert(this == JavaThread::current(), "Can't print stack of other threads");
1708 if (!has_last_Java_frame()) {
1709 ResourceMark rm(this);
1710 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1711 if (buf == nullptr) {
1712 tty->print_cr("Unable to print native stack - out of memory");
1713 return;
1714 }
1715 address lastpc = nullptr;
1716 if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) {
1717 // We have printed the native stack in platform-specific code,
1718 // so nothing else to do in this case.
1719 } else {
1720 frame f = os::current_frame();
1721 VMError::print_native_stack(tty, f, this, true /*print_source_info */,
1722 -1 /* max stack */, buf, O_BUFLEN);
1723 }
1724 } else {
1725 print_active_stack_on(tty);
1726 }
1727 }
1728
1729 void JavaThread::print_stack_on(outputStream* st) {
1730 if (!has_last_Java_frame()) return;
1731
1732 Thread* current_thread = Thread::current();
1733 ResourceMark rm(current_thread);
1734 HandleMark hm(current_thread);
1735
1736 RegisterMap reg_map(this,
1737 RegisterMap::UpdateMap::include,
1738 RegisterMap::ProcessFrames::include,
1739 RegisterMap::WalkContinuation::skip);
1740 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1741 int count = 0;
1742 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1743 if (f->is_java_frame()) {
1744 javaVFrame* jvf = javaVFrame::cast(f);
1745 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1746
1747 // Print out lock information
1748 if (JavaMonitorsInStackTrace) {
1749 jvf->print_lock_info_on(st, count);
1750 }
1751 } else {
1752 // Ignore non-Java frames
1753 }
1754
1755 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1756 count++;
1757 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1758 }
1759 }
1760
1761 void JavaThread::print_vthread_stack_on(outputStream* st) {
1762 assert(is_vthread_mounted(), "Caller should have checked this");
1763 assert(has_last_Java_frame(), "must be");
1764
1765 Thread* current_thread = Thread::current();
1766 ResourceMark rm(current_thread);
1767 HandleMark hm(current_thread);
1768
1769 RegisterMap reg_map(this,
1770 RegisterMap::UpdateMap::include,
1771 RegisterMap::ProcessFrames::include,
1772 RegisterMap::WalkContinuation::include);
1773 ContinuationEntry* cont_entry = last_continuation();
1774 vframe* start_vf = last_java_vframe(®_map);
1775 int count = 0;
1776 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1777 // Watch for end of vthread stack
1778 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1779 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1780 if (cont_entry->is_virtual_thread()) {
1781 break;
1782 }
1783 cont_entry = cont_entry->parent();
1784 }
1785 if (f->is_java_frame()) {
1786 javaVFrame* jvf = javaVFrame::cast(f);
1787 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1788
1789 // Print out lock information
1790 if (JavaMonitorsInStackTrace) {
1791 jvf->print_lock_info_on(st, count);
1792 }
1793 } else {
1794 // Ignore non-Java frames
1795 }
1796
1797 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1798 count++;
1799 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1800 }
1801 }
1802
1803 void JavaThread::print_active_stack_on(outputStream* st) {
1804 if (is_vthread_mounted()) {
1805 print_vthread_stack_on(st);
1806 } else {
1807 print_stack_on(st);
1808 }
1809 }
1810
1811 #if INCLUDE_JVMTI
1812 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1813 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1814 set_jvmti_vthread(thread_oop);
1815
1816 // unbind current JvmtiThreadState from JavaThread
1817 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1818
1819 // bind new JvmtiThreadState to JavaThread
1820 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1821
1822 return jvmti_thread_state();
1823 }
1824 #endif
1825
1826 // JVMTI PopFrame support
1827 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1828 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1829 if (in_bytes(size_in_bytes) != 0) {
1830 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1831 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1832 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1833 }
1834 }
1835
1836 void* JavaThread::popframe_preserved_args() {
1837 return _popframe_preserved_args;
1838 }
1839
1840 ByteSize JavaThread::popframe_preserved_args_size() {
1841 return in_ByteSize(_popframe_preserved_args_size);
1842 }
1843
1844 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1845 int sz = in_bytes(popframe_preserved_args_size());
1846 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1847 return in_WordSize(sz / wordSize);
1848 }
1849
1850 void JavaThread::popframe_free_preserved_args() {
1851 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1852 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1853 _popframe_preserved_args = nullptr;
1854 _popframe_preserved_args_size = 0;
1855 }
1856
1857 #ifndef PRODUCT
1858
1859 void JavaThread::trace_frames() {
1860 tty->print_cr("[Describe stack]");
1861 int frame_no = 1;
1862 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1863 tty->print(" %d. ", frame_no++);
1864 fst.current()->print_value_on(tty, this);
1865 tty->cr();
1866 }
1867 }
1868
1869 class PrintAndVerifyOopClosure: public OopClosure {
1870 protected:
1871 template <class T> inline void do_oop_work(T* p) {
1872 oop obj = RawAccess<>::oop_load(p);
1873 if (obj == nullptr) return;
1874 tty->print(INTPTR_FORMAT ": ", p2i(p));
1875 if (oopDesc::is_oop_or_null(obj)) {
1876 if (obj->is_objArray()) {
1877 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1878 } else {
1879 obj->print();
1880 }
1881 } else {
1882 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1883 }
1884 tty->cr();
1885 }
1886 public:
1887 virtual void do_oop(oop* p) { do_oop_work(p); }
1888 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1889 };
1890
1891 #ifdef ASSERT
1892 // Print or validate the layout of stack frames
1893 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1894 ResourceMark rm;
1895 PreserveExceptionMark pm(this);
1896 FrameValues values;
1897 int frame_no = 0;
1898 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1899 fst.current()->describe(values, ++frame_no, fst.register_map());
1900 if (depth == frame_no) break;
1901 }
1902 Continuation::describe(values);
1903 if (validate_only) {
1904 values.validate();
1905 } else {
1906 tty->print_cr("[Describe stack layout]");
1907 values.print(this);
1908 }
1909 }
1910 #endif
1911
1912 void JavaThread::trace_stack_from(vframe* start_vf) {
1913 ResourceMark rm;
1914 int vframe_no = 1;
1915 for (vframe* f = start_vf; f; f = f->sender()) {
1916 if (f->is_java_frame()) {
1917 javaVFrame::cast(f)->print_activation(vframe_no++);
1918 } else {
1919 f->print();
1920 }
1921 if (vframe_no > StackPrintLimit) {
1922 tty->print_cr("...<more frames>...");
1923 return;
1924 }
1925 }
1926 }
1927
1928
1929 void JavaThread::trace_stack() {
1930 if (!has_last_Java_frame()) return;
1931 Thread* current_thread = Thread::current();
1932 ResourceMark rm(current_thread);
1933 HandleMark hm(current_thread);
1934 RegisterMap reg_map(this,
1935 RegisterMap::UpdateMap::include,
1936 RegisterMap::ProcessFrames::include,
1937 RegisterMap::WalkContinuation::skip);
1938 trace_stack_from(last_java_vframe(®_map));
1939 }
1940
1941
1942 #endif // PRODUCT
1943
1944 void JavaThread::inc_held_monitor_count(int i, bool jni) {
1945 #ifdef SUPPORT_MONITOR_COUNT
1946 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1947 _held_monitor_count += i;
1948 if (jni) {
1949 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1950 _jni_monitor_count += i;
1951 }
1952 #endif
1953 }
1954
1955 void JavaThread::dec_held_monitor_count(int i, bool jni) {
1956 #ifdef SUPPORT_MONITOR_COUNT
1957 _held_monitor_count -= i;
1958 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_held_monitor_count);
1959 if (jni) {
1960 _jni_monitor_count -= i;
1961 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INT64_FORMAT, (int64_t)_jni_monitor_count);
1962 }
1963 #endif
1964 }
1965
1966 frame JavaThread::vthread_last_frame() {
1967 assert (is_vthread_mounted(), "Virtual thread not mounted");
1968 return last_frame();
1969 }
1970
1971 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1972 const ContinuationEntry* entry = vthread_continuation();
1973 guarantee (entry != nullptr, "Not a carrier thread");
1974 frame f = entry->to_frame();
1975 if (reg_map->process_frames()) {
1976 entry->flush_stack_processing(this);
1977 }
1978 entry->update_register_map(reg_map);
1979 return f.sender(reg_map);
1980 }
1981
1982 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1983 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1984 }
1985
1986 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
1987 assert(reg_map != nullptr, "a map must be given");
1988 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
1989 if (vf->is_java_frame()) return javaVFrame::cast(vf);
1990 }
1991 return nullptr;
1992 }
1993
1994 Klass* JavaThread::security_get_caller_class(int depth) {
1995 ResetNoHandleMark rnhm;
1996 HandleMark hm(Thread::current());
1997
1998 vframeStream vfst(this);
1999 vfst.security_get_caller_frame(depth);
2000 if (!vfst.at_end()) {
2001 return vfst.method()->method_holder();
2002 }
2003 return nullptr;
2004 }
2005
2006 // Internal convenience function for millisecond resolution sleeps.
2007 bool JavaThread::sleep(jlong millis) {
2008 jlong nanos;
2009 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2010 // Conversion to nanos would overflow, saturate at max
2011 nanos = max_jlong;
2012 } else {
2013 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2014 }
2015 return sleep_nanos(nanos);
2016 }
2017
2018 // java.lang.Thread.sleep support
2019 // Returns true if sleep time elapsed as expected, and false
2020 // if the thread was interrupted.
2021 bool JavaThread::sleep_nanos(jlong nanos) {
2022 assert(this == Thread::current(), "thread consistency check");
2023 assert(nanos >= 0, "nanos are in range");
2024
2025 ParkEvent * const slp = this->_SleepEvent;
2026 // Because there can be races with thread interruption sending an unpark()
2027 // to the event, we explicitly reset it here to avoid an immediate return.
2028 // The actual interrupt state will be checked before we park().
2029 slp->reset();
2030 // Thread interruption establishes a happens-before ordering in the
2031 // Java Memory Model, so we need to ensure we synchronize with the
2032 // interrupt state.
2033 OrderAccess::fence();
2034
2035 jlong prevtime = os::javaTimeNanos();
2036
2037 jlong nanos_remaining = nanos;
2038
2039 for (;;) {
2040 // interruption has precedence over timing out
2041 if (this->is_interrupted(true)) {
2042 return false;
2043 }
2044
2045 if (nanos_remaining <= 0) {
2046 return true;
2047 }
2048
2049 {
2050 ThreadBlockInVM tbivm(this);
2051 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2052 slp->park_nanos(nanos_remaining);
2053 }
2054
2055 // Update elapsed time tracking
2056 jlong newtime = os::javaTimeNanos();
2057 if (newtime - prevtime < 0) {
2058 // time moving backwards, should only happen if no monotonic clock
2059 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2060 assert(false,
2061 "unexpected time moving backwards detected in JavaThread::sleep()");
2062 } else {
2063 nanos_remaining -= (newtime - prevtime);
2064 }
2065 prevtime = newtime;
2066 }
2067 }
2068
2069 // Last thread running calls java.lang.Shutdown.shutdown()
2070 void JavaThread::invoke_shutdown_hooks() {
2071 HandleMark hm(this);
2072
2073 // We could get here with a pending exception, if so clear it now.
2074 if (this->has_pending_exception()) {
2075 this->clear_pending_exception();
2076 }
2077
2078 EXCEPTION_MARK;
2079 Klass* shutdown_klass =
2080 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2081 THREAD);
2082 if (shutdown_klass != nullptr) {
2083 // SystemDictionary::resolve_or_null will return null if there was
2084 // an exception. If we cannot load the Shutdown class, just don't
2085 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2086 // won't be run. Note that if a shutdown hook was registered,
2087 // the Shutdown class would have already been loaded
2088 // (Runtime.addShutdownHook will load it).
2089 JavaValue result(T_VOID);
2090 JavaCalls::call_static(&result,
2091 shutdown_klass,
2092 vmSymbols::shutdown_name(),
2093 vmSymbols::void_method_signature(),
2094 THREAD);
2095 }
2096 CLEAR_PENDING_EXCEPTION;
2097 }
2098
2099 #ifndef PRODUCT
2100 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2101 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2102 }
2103 #endif
2104
2105 // Helper function to create the java.lang.Thread object for a
2106 // VM-internal thread. The thread will have the given name, and be
2107 // a member of the "system" ThreadGroup.
2108 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2109 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2110
2111 // Initialize thread_oop to put it into the system threadGroup.
2112 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2113 Handle thread_group(THREAD, Universe::system_thread_group());
2114 Handle thread_oop =
2115 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2116 vmSymbols::threadgroup_string_void_signature(),
2117 thread_group,
2118 string,
2119 CHECK_NH);
2120
2121 return thread_oop;
2122 }
2123
2124 // Starts the target JavaThread as a daemon of the given priority, and
2125 // bound to the given java.lang.Thread instance.
2126 // The Threads_lock is held for the duration.
2127 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2128 Handle thread_oop, ThreadPriority prio) {
2129
2130 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2131
2132 MutexLocker mu(current, Threads_lock);
2133
2134 // Initialize the fields of the thread_oop first.
2135 if (prio != NoPriority) {
2136 java_lang_Thread::set_priority(thread_oop(), prio);
2137 // Note: we don't call os::set_priority here. Possibly we should,
2138 // else all threads should call it themselves when they first run.
2139 }
2140
2141 java_lang_Thread::set_daemon(thread_oop());
2142
2143 // Now bind the thread_oop to the target JavaThread.
2144 target->set_threadOopHandles(thread_oop());
2145
2146 Threads::add(target); // target is now visible for safepoint/handshake
2147 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2148 // on a ThreadsList. We don't want to wait for the release when the
2149 // Theads_lock is dropped when the 'mu' destructor is run since the
2150 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2151 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2152 Thread::start(target);
2153 }
2154
2155 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2156 // At this point it may be possible that no osthread was created for the
2157 // JavaThread due to lack of resources. However, since this must work
2158 // for critical system threads just check and abort if this fails.
2159 if (thread->osthread() == nullptr) {
2160 // This isn't really an OOM condition, but historically this is what
2161 // we report.
2162 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2163 os::native_thread_creation_failed_msg());
2164 }
2165 }
2166
2167 void JavaThread::pretouch_stack() {
2168 // Given an established java thread stack with usable area followed by
2169 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2170 // from the current frame down to the start of the shadow zone.
2171 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2172 if (is_in_full_stack(end)) {
2173 char* p1 = (char*) alloca(1);
2174 address here = (address) &p1;
2175 if (is_in_full_stack(here) && here > end) {
2176 size_t to_alloc = here - end;
2177 char* p2 = (char*) alloca(to_alloc);
2178 log_trace(os, thread)("Pretouching thread stack from " PTR_FORMAT " to " PTR_FORMAT ".",
2179 p2i(p2), p2i(end));
2180 os::pretouch_memory(p2, p2 + to_alloc,
2181 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2182 }
2183 }
2184 }
2185
2186 // Deferred OopHandle release support.
2187
2188 class OopHandleList : public CHeapObj<mtInternal> {
2189 static const int _count = 4;
2190 OopHandle _handles[_count];
2191 OopHandleList* _next;
2192 int _index;
2193 public:
2194 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2195 void add(OopHandle h) {
2196 assert(_index < _count, "too many additions");
2197 _handles[_index++] = h;
2198 }
2199 ~OopHandleList() {
2200 assert(_index == _count, "usage error");
2201 for (int i = 0; i < _index; i++) {
2202 _handles[i].release(JavaThread::thread_oop_storage());
2203 }
2204 }
2205 OopHandleList* next() const { return _next; }
2206 };
2207
2208 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2209
2210 // Called by the ServiceThread to do the work of releasing
2211 // the OopHandles.
2212 void JavaThread::release_oop_handles() {
2213 OopHandleList* list;
2214 {
2215 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2216 list = _oop_handle_list;
2217 _oop_handle_list = nullptr;
2218 }
2219 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2220
2221 while (list != nullptr) {
2222 OopHandleList* l = list;
2223 list = l->next();
2224 delete l;
2225 }
2226 }
2227
2228 // Add our OopHandles for later release.
2229 void JavaThread::add_oop_handles_for_release() {
2230 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2231 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2232 new_head->add(_threadObj);
2233 new_head->add(_vthread);
2234 new_head->add(_jvmti_vthread);
2235 new_head->add(_scopedValueCache);
2236 _oop_handle_list = new_head;
2237 Service_lock->notify_all();
2238 }