1 /*
2 * Copyright (c) 1997, 2025, 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 "cds/dynamicArchive.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/javaThreadStatus.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmClasses.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compilerThread.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/oopStorage.hpp"
38 #include "gc/shared/oopStorageSet.hpp"
39 #include "gc/shared/tlab_globals.hpp"
40 #include "jfr/jfrEvents.hpp"
41 #include "jvm.h"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logAsyncWriter.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/allocation.inline.hpp"
47 #include "memory/iterator.hpp"
48 #include "memory/universe.hpp"
49 #include "oops/access.inline.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/klass.inline.hpp"
52 #include "oops/oop.inline.hpp"
53 #include "oops/oopHandle.inline.hpp"
54 #include "oops/verifyOopClosure.hpp"
55 #include "prims/jvm_misc.hpp"
56 #include "prims/jvmtiDeferredUpdates.hpp"
57 #include "prims/jvmtiExport.hpp"
58 #include "prims/jvmtiThreadState.inline.hpp"
59 #include "runtime/atomicAccess.hpp"
60 #include "runtime/continuation.hpp"
61 #include "runtime/continuationEntry.inline.hpp"
62 #include "runtime/continuationHelper.inline.hpp"
63 #include "runtime/deoptimization.hpp"
64 #include "runtime/frame.inline.hpp"
65 #include "runtime/handles.inline.hpp"
66 #include "runtime/handshake.hpp"
67 #include "runtime/interfaceSupport.inline.hpp"
68 #include "runtime/java.hpp"
69 #include "runtime/javaCalls.hpp"
70 #include "runtime/javaThread.inline.hpp"
71 #include "runtime/jniHandles.inline.hpp"
72 #include "runtime/lockStack.inline.hpp"
73 #include "runtime/mutexLocker.hpp"
74 #include "runtime/orderAccess.hpp"
75 #include "runtime/os.inline.hpp"
76 #include "runtime/osThread.hpp"
77 #include "runtime/safepoint.hpp"
78 #include "runtime/safepointMechanism.inline.hpp"
79 #include "runtime/safepointVerifiers.hpp"
80 #include "runtime/serviceThread.hpp"
81 #include "runtime/stackFrameStream.inline.hpp"
82 #include "runtime/stackWatermarkSet.hpp"
83 #include "runtime/synchronizer.hpp"
84 #include "runtime/threadIdentifier.hpp"
85 #include "runtime/threadSMR.inline.hpp"
86 #include "runtime/threadStatisticalInfo.hpp"
87 #include "runtime/threadWXSetters.inline.hpp"
88 #include "runtime/timer.hpp"
89 #include "runtime/timerTrace.hpp"
90 #include "runtime/vframe.inline.hpp"
91 #include "runtime/vframe_hp.hpp"
92 #include "runtime/vframeArray.hpp"
93 #include "runtime/vmOperations.hpp"
94 #include "runtime/vmThread.hpp"
95 #include "services/threadService.hpp"
96 #include "utilities/copy.hpp"
97 #include "utilities/defaultStream.hpp"
98 #include "utilities/dtrace.hpp"
99 #include "utilities/events.hpp"
100 #include "utilities/macros.hpp"
101 #include "utilities/nativeStackPrinter.hpp"
102 #include "utilities/preserveException.hpp"
103 #include "utilities/spinYield.hpp"
104 #include "utilities/vmError.hpp"
105 #if INCLUDE_JVMCI
106 #include "jvmci/jvmci.hpp"
107 #include "jvmci/jvmciEnv.hpp"
108 #endif
109 #if INCLUDE_JFR
110 #include "jfr/jfr.hpp"
111 #endif
112
113 // Set by os layer.
114 size_t JavaThread::_stack_size_at_create = 0;
115
116 #ifdef DTRACE_ENABLED
117
118 // Only bother with this argument setup if dtrace is available
119
120 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
121 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->name(); \
128 len = strlen(name); \
129 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
130 (char *) name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (uintptr_t) (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else // ndef DTRACE_ENABLED
137
138 #define DTRACE_THREAD_PROBE(probe, javathread)
139
140 #endif // ndef DTRACE_ENABLED
141
142 void JavaThread::smr_delete() {
143 if (_on_thread_list) {
144 ThreadsSMRSupport::smr_delete(this);
145 } else {
146 delete this;
147 }
148 }
149
150 // Initialized by VMThread at vm_global_init
151 OopStorage* JavaThread::_thread_oop_storage = nullptr;
152
153 OopStorage* JavaThread::thread_oop_storage() {
154 assert(_thread_oop_storage != nullptr, "not yet initialized");
155 return _thread_oop_storage;
156 }
157
158 void JavaThread::set_threadOopHandles(oop p) {
159 assert(_thread_oop_storage != nullptr, "not yet initialized");
160 _threadObj = OopHandle(_thread_oop_storage, p);
161 _vthread = OopHandle(_thread_oop_storage, p);
162 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
163 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
164 }
165
166 oop JavaThread::threadObj() const {
167 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
168 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
169 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
170 // Instead callers must verify oop safe access.
171 return _threadObj.resolve();
172 }
173
174 oop JavaThread::vthread() const {
175 return _vthread.resolve();
176 }
177
178 void JavaThread::set_vthread(oop p) {
179 assert(_thread_oop_storage != nullptr, "not yet initialized");
180 _vthread.replace(p);
181 }
182
183 oop JavaThread::jvmti_vthread() const {
184 return _jvmti_vthread.resolve();
185 }
186
187 void JavaThread::set_jvmti_vthread(oop p) {
188 assert(_thread_oop_storage != nullptr, "not yet initialized");
189 _jvmti_vthread.replace(p);
190 }
191
192 // If there is a virtual thread mounted then return vthread() oop.
193 // Otherwise, return threadObj().
194 oop JavaThread::vthread_or_thread() const {
195 oop result = vthread();
196 if (result == nullptr) {
197 result = threadObj();
198 }
199 return result;
200 }
201
202 oop JavaThread::scopedValueCache() const {
203 return _scopedValueCache.resolve();
204 }
205
206 void JavaThread::set_scopedValueCache(oop p) {
207 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
208 _scopedValueCache.replace(p);
209 } else {
210 assert(p == nullptr, "not yet initialized");
211 }
212 }
213
214 void JavaThread::clear_scopedValueBindings() {
215 set_scopedValueCache(nullptr);
216 oop vthread_oop = vthread();
217 // vthread may be null here if we get a VM error during startup,
218 // before the java.lang.Thread instance has been created.
219 if (vthread_oop != nullptr) {
220 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
221 }
222 }
223
224 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
225 bool daemon, TRAPS) {
226 assert(thread_group.not_null(), "thread group should be specified");
227 assert(threadObj() == nullptr, "should only create Java thread object once");
228
229 InstanceKlass* ik = vmClasses::Thread_klass();
230 assert(ik->is_initialized(), "must be");
231 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
232
233 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
234 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
235 // constructor calls Thread.current(), which must be set here.
236 java_lang_Thread::set_thread(thread_oop(), this);
237 set_threadOopHandles(thread_oop());
238
239 JavaValue result(T_VOID);
240 if (thread_name != nullptr) {
241 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
242 // Thread gets assigned specified name and null target
243 JavaCalls::call_special(&result,
244 thread_oop,
245 ik,
246 vmSymbols::object_initializer_name(),
247 vmSymbols::threadgroup_string_void_signature(),
248 thread_group,
249 name,
250 CHECK);
251 } else {
252 // Thread gets assigned name "Thread-nnn" and null target
253 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
254 JavaCalls::call_special(&result,
255 thread_oop,
256 ik,
257 vmSymbols::object_initializer_name(),
258 vmSymbols::threadgroup_runnable_void_signature(),
259 thread_group,
260 Handle(),
261 CHECK);
262 }
263
264 os::set_priority(this, NormPriority);
265
266 if (daemon) {
267 java_lang_Thread::set_daemon(thread_oop());
268 }
269 }
270
271 // ======= JavaThread ========
272
273 #if INCLUDE_JVMCI
274
275 jlong* JavaThread::_jvmci_old_thread_counters;
276
277 static bool jvmci_counters_include(JavaThread* thread) {
278 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
279 }
280
281 void JavaThread::collect_counters(jlong* array, int length) {
282 assert(length == JVMCICounterSize, "wrong value");
283 for (int i = 0; i < length; i++) {
284 array[i] = _jvmci_old_thread_counters[i];
285 }
286 for (JavaThread* tp : ThreadsListHandle()) {
287 if (jvmci_counters_include(tp)) {
288 for (int i = 0; i < length; i++) {
289 array[i] += tp->_jvmci_counters[i];
290 }
291 }
292 }
293 }
294
295 // Attempt to enlarge the array for per thread counters.
296 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
297 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
298 if (new_counters == nullptr) {
299 return nullptr;
300 }
301 if (old_counters == nullptr) {
302 old_counters = new_counters;
303 memset(old_counters, 0, sizeof(jlong) * new_size);
304 } else {
305 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
306 new_counters[i] = old_counters[i];
307 }
308 if (new_size > current_size) {
309 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
310 }
311 FREE_C_HEAP_ARRAY(jlong, old_counters);
312 }
313 return new_counters;
314 }
315
316 // Attempt to enlarge the array for per thread counters.
317 bool JavaThread::resize_counters(int current_size, int new_size) {
318 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
319 if (new_counters == nullptr) {
320 return false;
321 } else {
322 _jvmci_counters = new_counters;
323 return true;
324 }
325 }
326
327 class VM_JVMCIResizeCounters : public VM_Operation {
328 private:
329 int _new_size;
330 bool _failed;
331
332 public:
333 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
334 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
335 bool allow_nested_vm_operations() const { return true; }
336 void doit() {
337 // Resize the old thread counters array
338 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
339 if (new_counters == nullptr) {
340 _failed = true;
341 return;
342 } else {
343 JavaThread::_jvmci_old_thread_counters = new_counters;
344 }
345
346 // Now resize each threads array
347 for (JavaThread* tp : ThreadsListHandle()) {
348 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
349 _failed = true;
350 break;
351 }
352 }
353 if (!_failed) {
354 JVMCICounterSize = _new_size;
355 }
356 }
357
358 bool failed() { return _failed; }
359 };
360
361 bool JavaThread::resize_all_jvmci_counters(int new_size) {
362 VM_JVMCIResizeCounters op(new_size);
363 VMThread::execute(&op);
364 return !op.failed();
365 }
366
367 #endif // INCLUDE_JVMCI
368
369 #ifdef ASSERT
370 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
371 void JavaThread::check_possible_safepoint() {
372 if (_no_safepoint_count > 0) {
373 print_owned_locks();
374 assert(false, "Possible safepoint reached by thread that does not allow it");
375 }
376 #ifdef CHECK_UNHANDLED_OOPS
377 // Clear unhandled oops in JavaThreads so we get a crash right away.
378 clear_unhandled_oops();
379 #endif // CHECK_UNHANDLED_OOPS
380
381 // Macos/aarch64 should be in the right state for safepoint (e.g.
382 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
383 // happens in practice, making such issues hard to find and reproduce.
384 #if defined(__APPLE__) && defined(AARCH64)
385 if (AssertWXAtThreadSync) {
386 assert_wx_state(WXWrite);
387 }
388 #endif
389 }
390
391 void JavaThread::check_for_valid_safepoint_state() {
392 // Don't complain if running a debugging command.
393 if (DebuggingContext::is_enabled()) return;
394
395 // Check NoSafepointVerifier, which is implied by locks taken that can be
396 // shared with the VM thread. This makes sure that no locks with allow_vm_block
397 // are held.
398 check_possible_safepoint();
399
400 if (thread_state() != _thread_in_vm) {
401 fatal("LEAF method calling lock?");
402 }
403
404 if (GCALotAtAllSafepoints) {
405 // We could enter a safepoint here and thus have a gc
406 InterfaceSupport::check_gc_alot();
407 }
408 }
409 #endif // ASSERT
410
411 // A JavaThread is a normal Java thread
412
413 JavaThread::JavaThread(MemTag mem_tag) :
414 Thread(mem_tag),
415 // Initialize fields
416 _on_thread_list(false),
417 DEBUG_ONLY(_java_call_counter(0) COMMA)
418 _entry_point(nullptr),
419 _deopt_mark(nullptr),
420 _deopt_nmethod(nullptr),
421 _vframe_array_head(nullptr),
422 _vframe_array_last(nullptr),
423 _jvmti_deferred_updates(nullptr),
424 _callee_target(nullptr),
425 _vm_result_oop(nullptr),
426 _vm_result_metadata(nullptr),
427
428 _current_pending_monitor(nullptr),
429 _current_pending_monitor_is_from_java(true),
430 _current_waiting_monitor(nullptr),
431 _active_handles(nullptr),
432 _free_handle_block(nullptr),
433 _monitor_owner_id(0),
434
435 _suspend_flags(0),
436
437 _thread_state(_thread_new),
438 _saved_exception_pc(nullptr),
439 #ifdef ASSERT
440 _no_safepoint_count(0),
441 _visited_for_critical_count(false),
442 #endif
443
444 _terminated(_not_terminated),
445 _in_deopt_handler(0),
446 _doing_unsafe_access(false),
447 _do_not_unlock_if_synchronized(false),
448 #if INCLUDE_JVMTI
449 _carrier_thread_suspended(false),
450 _is_in_VTMS_transition(false),
451 _is_disable_suspend(false),
452 _is_in_java_upcall(false),
453 _VTMS_transition_mark(false),
454 _on_monitor_waited_event(false),
455 _contended_entered_monitor(nullptr),
456 #ifdef ASSERT
457 _is_VTMS_transition_disabler(false),
458 #endif
459 #endif
460 _jni_attach_state(_not_attaching_via_jni),
461 _is_in_internal_oome_mark(false),
462 #if INCLUDE_JVMCI
463 _pending_deoptimization(-1),
464 _pending_monitorenter(false),
465 _pending_transfer_to_interpreter(false),
466 _pending_failed_speculation(0),
467 _jvmci{nullptr},
468 _libjvmci_runtime(nullptr),
469 _jvmci_counters(nullptr),
470 _jvmci_reserved0(0),
471 _jvmci_reserved1(0),
472 _jvmci_reserved_oop0(nullptr),
473 _live_nmethod(nullptr),
474 #endif // INCLUDE_JVMCI
475
476 _exception_oop(oop()),
477 _exception_pc(nullptr),
478 _exception_handler_pc(nullptr),
479
480 _jni_active_critical(0),
481 _pending_jni_exception_check_fn(nullptr),
482 _depth_first_number(0),
483
484 // JVMTI PopFrame support
485 _popframe_condition(popframe_inactive),
486 _frames_to_pop_failed_realloc(0),
487
488 _cont_entry(nullptr),
489 _cont_fastpath(nullptr),
490 _cont_fastpath_thread_state(1),
491 _unlocked_inflated_monitor(nullptr),
492
493 _preempt_alternate_return(nullptr),
494 _preemption_cancelled(false),
495 _pending_interrupted_exception(false),
496
497 _handshake(this),
498 _suspend_resume_manager(this, &_handshake._lock),
499
500 _popframe_preserved_args(nullptr),
501 _popframe_preserved_args_size(0),
502
503 _jvmti_thread_state(nullptr),
504 _interp_only_mode(0),
505 _should_post_on_exceptions_flag(JNI_FALSE),
506 _thread_stat(new ThreadStatistics()),
507
508 _parker(),
509
510 _class_to_be_initialized(nullptr),
511 _class_being_initialized(nullptr),
512
513 _SleepEvent(ParkEvent::Allocate(this)),
514
515 #if INCLUDE_JFR
516 _last_freeze_fail_result(freeze_ok),
517 #endif
518
519 _lock_stack(this),
520 _om_cache(this) {
521 set_jni_functions(jni_functions());
522
523 #if INCLUDE_JVMCI
524 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
525 if (JVMCICounterSize > 0) {
526 resize_counters(0, (int) JVMCICounterSize);
527 }
528 #endif // INCLUDE_JVMCI
529
530 // Setup safepoint state info for this thread
531 ThreadSafepointState::create(this);
532
533 SafepointMechanism::initialize_header(this);
534
535 set_requires_cross_modify_fence(false);
536
537 pd_initialize();
538 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
539 }
540
541 JavaThread* JavaThread::create_attaching_thread() {
542 JavaThread* jt = new JavaThread();
543 jt->_jni_attach_state = _attaching_via_jni;
544 return jt;
545 }
546
547 // interrupt support
548
549 void JavaThread::interrupt() {
550 // All callers should have 'this' thread protected by a
551 // ThreadsListHandle so that it cannot terminate and deallocate
552 // itself.
553 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
554
555 // For Windows _interrupt_event
556 WINDOWS_ONLY(osthread()->set_interrupted(true);)
557
558 // For Thread.sleep
559 _SleepEvent->unpark();
560
561 // For JSR166 LockSupport.park
562 parker()->unpark();
563
564 // For ObjectMonitor and JvmtiRawMonitor
565 _ParkEvent->unpark();
566 }
567
568 bool JavaThread::is_interrupted(bool clear_interrupted) {
569 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
570
571 if (_threadObj.peek() == nullptr) {
572 // If there is no j.l.Thread then it is impossible to have
573 // been interrupted. We can find null during VM initialization
574 // or when a JNI thread is still in the process of attaching.
575 // In such cases this must be the current thread.
576 assert(this == Thread::current(), "invariant");
577 return false;
578 }
579
580 bool interrupted = java_lang_Thread::interrupted(threadObj());
581
582 // NOTE that since there is no "lock" around the interrupt and
583 // is_interrupted operations, there is the possibility that the
584 // interrupted flag will be "false" but that the
585 // low-level events will be in the signaled state. This is
586 // intentional. The effect of this is that Object.wait() and
587 // LockSupport.park() will appear to have a spurious wakeup, which
588 // is allowed and not harmful, and the possibility is so rare that
589 // it is not worth the added complexity to add yet another lock.
590 // For the sleep event an explicit reset is performed on entry
591 // to JavaThread::sleep, so there is no early return. It has also been
592 // recommended not to put the interrupted flag into the "event"
593 // structure because it hides the issue.
594 // Also, because there is no lock, we must only clear the interrupt
595 // state if we are going to report that we were interrupted; otherwise
596 // an interrupt that happens just after we read the field would be lost.
597 if (interrupted && clear_interrupted) {
598 assert(this == Thread::current(), "only the current thread can clear");
599 java_lang_Thread::set_interrupted(threadObj(), false);
600 WINDOWS_ONLY(osthread()->set_interrupted(false);)
601 }
602 return interrupted;
603 }
604
605 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
606 // the Java code in Object::wait which are not present in RawMonitorWait.
607 bool JavaThread::get_and_clear_interrupted() {
608 if (!is_interrupted(false)) {
609 return false;
610 }
611 oop thread_oop = vthread_or_thread();
612 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
613
614 if (!is_virtual) {
615 return is_interrupted(true);
616 }
617 // Virtual thread: clear interrupt status for both virtual and
618 // carrier threads under the interruptLock protection.
619 JavaThread* current = JavaThread::current();
620 HandleMark hm(current);
621 Handle thread_h(current, thread_oop);
622 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
623
624 // re-check the interrupt status under the interruptLock protection
625 bool interrupted = java_lang_Thread::interrupted(thread_h());
626
627 if (interrupted) {
628 assert(this == Thread::current(), "only the current thread can clear");
629 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
630 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
631 WINDOWS_ONLY(osthread()->set_interrupted(false);)
632 }
633 return interrupted;
634 }
635
636 void JavaThread::block_if_vm_exited() {
637 if (_terminated == _vm_exited) {
638 // _vm_exited is set at safepoint, and Threads_lock is never released
639 // so we will block here forever.
640 // Here we can be doing a jump from a safe state to an unsafe state without
641 // proper transition, but it happens after the final safepoint has begun so
642 // this jump won't cause any safepoint problems.
643 set_thread_state(_thread_in_vm);
644 Threads_lock->lock();
645 ShouldNotReachHere();
646 }
647 }
648
649 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
650 set_entry_point(entry_point);
651 // Create the native thread itself.
652 // %note runtime_23
653 os::ThreadType thr_type = os::java_thread;
654 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
655 os::java_thread;
656 os::create_thread(this, thr_type, stack_sz);
657 // The _osthread may be null here because we ran out of memory (too many threads active).
658 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
659 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
660 // the exception consists of creating the exception object & initializing it, initialization
661 // will leave the VM via a JavaCall and then all locks must be unlocked).
662 //
663 // The thread is still suspended when we reach here. Thread must be explicit started
664 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
665 // by calling Threads:add. The reason why this is not done here, is because the thread
666 // object must be fully initialized (take a look at JVM_Start)
667 }
668
669 JavaThread::~JavaThread() {
670
671 // Enqueue OopHandles for release by the service thread.
672 add_oop_handles_for_release();
673
674 // Return the sleep event to the free list
675 ParkEvent::Release(_SleepEvent);
676 _SleepEvent = nullptr;
677
678 // Free any remaining previous UnrollBlock
679 vframeArray* old_array = vframe_array_last();
680
681 if (old_array != nullptr) {
682 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
683 old_array->set_unroll_block(nullptr);
684 delete old_info;
685 delete old_array;
686 }
687
688 JvmtiDeferredUpdates* updates = deferred_updates();
689 if (updates != nullptr) {
690 // This can only happen if thread is destroyed before deoptimization occurs.
691 assert(updates->count() > 0, "Updates holder not deleted");
692 // free deferred updates.
693 delete updates;
694 set_deferred_updates(nullptr);
695 }
696
697 // All Java related clean up happens in exit
698 ThreadSafepointState::destroy(this);
699 if (_thread_stat != nullptr) delete _thread_stat;
700
701 #if INCLUDE_JVMCI
702 if (JVMCICounterSize > 0) {
703 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
704 }
705 #endif // INCLUDE_JVMCI
706 }
707
708
709 // First JavaThread specific code executed by a new Java thread.
710 void JavaThread::pre_run() {
711 // empty - see comments in run()
712 }
713
714 // The main routine called by a new Java thread. This isn't overridden
715 // by subclasses, instead different subclasses define a different "entry_point"
716 // which defines the actual logic for that kind of thread.
717 void JavaThread::run() {
718 // initialize thread-local alloc buffer related fields
719 initialize_tlab();
720
721 _stack_overflow_state.create_stack_guard_pages();
722
723 cache_global_variables();
724
725 // Thread is now sufficiently initialized to be handled by the safepoint code as being
726 // in the VM. Change thread state from _thread_new to _thread_in_vm
727 assert(this->thread_state() == _thread_new, "wrong thread state");
728 set_thread_state(_thread_in_vm);
729
730 // Before a thread is on the threads list it is always safe, so after leaving the
731 // _thread_new we should emit a instruction barrier. The distance to modified code
732 // from here is probably far enough, but this is consistent and safe.
733 OrderAccess::cross_modify_fence();
734
735 assert(JavaThread::current() == this, "sanity check");
736 assert(!Thread::current()->owns_locks(), "sanity check");
737
738 JFR_ONLY(Jfr::on_thread_start(this);)
739
740 DTRACE_THREAD_PROBE(start, this);
741
742 // This operation might block. We call that after all safepoint checks for a new thread has
743 // been completed.
744 set_active_handles(JNIHandleBlock::allocate_block());
745
746 if (JvmtiExport::should_post_thread_life()) {
747 JvmtiExport::post_thread_start(this);
748
749 }
750
751 if (AlwaysPreTouchStacks) {
752 pretouch_stack();
753 }
754
755 // We call another function to do the rest so we are sure that the stack addresses used
756 // from there will be lower than the stack base just computed.
757 thread_main_inner();
758 }
759
760 void JavaThread::thread_main_inner() {
761 assert(JavaThread::current() == this, "sanity check");
762 assert(_threadObj.peek() != nullptr, "just checking");
763
764 // Execute thread entry point unless this thread has a pending exception.
765 // Note: Due to JVMTI StopThread we can have pending exceptions already!
766 if (!this->has_pending_exception()) {
767 {
768 ResourceMark rm(this);
769 this->set_native_thread_name(this->name());
770 }
771 HandleMark hm(this);
772 this->entry_point()(this, this);
773 }
774
775 DTRACE_THREAD_PROBE(stop, this);
776
777 // Cleanup is handled in post_run()
778 }
779
780 // Shared teardown for all JavaThreads
781 void JavaThread::post_run() {
782 this->exit(false);
783 this->unregister_thread_stack_with_NMT();
784 // Defer deletion to here to ensure 'this' is still referenceable in call_run
785 // for any shared tear-down.
786 this->smr_delete();
787 }
788
789 static void ensure_join(JavaThread* thread) {
790 // We do not need to grab the Threads_lock, since we are operating on ourself.
791 Handle threadObj(thread, thread->threadObj());
792 assert(threadObj.not_null(), "java thread object must exist");
793 ObjectLocker lock(threadObj, thread);
794 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
795 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
796 // Clear the native thread instance - this makes isAlive return false and allows the join()
797 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
798 // requirements.
799 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
800 java_lang_Thread::release_set_thread(threadObj(), nullptr);
801 lock.notify_all(thread);
802 // Ignore pending exception, since we are exiting anyway
803 thread->clear_pending_exception();
804 }
805
806 static bool is_daemon(oop threadObj) {
807 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
808 }
809
810 // For any new cleanup additions, please check to see if they need to be applied to
811 // cleanup_failed_attach_current_thread as well.
812 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
813 assert(this == JavaThread::current(), "thread consistency check");
814 assert(!is_exiting(), "should not be exiting or terminated already");
815
816 elapsedTimer _timer_exit_phase1;
817 elapsedTimer _timer_exit_phase2;
818 elapsedTimer _timer_exit_phase3;
819 elapsedTimer _timer_exit_phase4;
820
821 om_clear_monitor_cache();
822
823 if (log_is_enabled(Debug, os, thread, timer)) {
824 _timer_exit_phase1.start();
825 }
826
827 HandleMark hm(this);
828 Handle uncaught_exception(this, this->pending_exception());
829 this->clear_pending_exception();
830 Handle threadObj(this, this->threadObj());
831 assert(threadObj.not_null(), "Java thread object should be created");
832
833 if (!destroy_vm) {
834 if (uncaught_exception.not_null()) {
835 EXCEPTION_MARK;
836 // Call method Thread.dispatchUncaughtException().
837 Klass* thread_klass = vmClasses::Thread_klass();
838 JavaValue result(T_VOID);
839 JavaCalls::call_virtual(&result,
840 threadObj, thread_klass,
841 vmSymbols::dispatchUncaughtException_name(),
842 vmSymbols::throwable_void_signature(),
843 uncaught_exception,
844 THREAD);
845 if (HAS_PENDING_EXCEPTION) {
846 ResourceMark rm(this);
847 jio_fprintf(defaultStream::error_stream(),
848 "\nException: %s thrown from the UncaughtExceptionHandler"
849 " in thread \"%s\"\n",
850 pending_exception()->klass()->external_name(),
851 name());
852 CLEAR_PENDING_EXCEPTION;
853 }
854 }
855
856 if (!is_Compiler_thread()) {
857 // We have finished executing user-defined Java code and now have to do the
858 // implementation specific clean-up by calling Thread.exit(). We prevent any
859 // asynchronous exceptions from being delivered while in Thread.exit()
860 // to ensure the clean-up is not corrupted.
861 NoAsyncExceptionDeliveryMark _no_async(this);
862
863 EXCEPTION_MARK;
864 JavaValue result(T_VOID);
865 Klass* thread_klass = vmClasses::Thread_klass();
866 JavaCalls::call_virtual(&result,
867 threadObj, thread_klass,
868 vmSymbols::exit_method_name(),
869 vmSymbols::void_method_signature(),
870 THREAD);
871 CLEAR_PENDING_EXCEPTION;
872 }
873
874 // notify JVMTI
875 if (JvmtiExport::should_post_thread_life()) {
876 JvmtiExport::post_thread_end(this);
877 }
878 } else {
879 // before_exit() has already posted JVMTI THREAD_END events
880 }
881
882 // Cleanup any pending async exception now since we cannot access oops after
883 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
884 if (has_async_exception_condition()) {
885 handshake_state()->clean_async_exception_operation();
886 }
887
888 // The careful dance between thread suspension and exit is handled here.
889 // Since we are in thread_in_vm state and suspension is done with handshakes,
890 // we can just put in the exiting state and it will be correctly handled.
891 // Also, no more async exceptions will be added to the queue after this point.
892 set_terminated(_thread_exiting);
893 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
894
895 if (log_is_enabled(Debug, os, thread, timer)) {
896 _timer_exit_phase1.stop();
897 _timer_exit_phase2.start();
898 }
899
900 // Capture daemon status before the thread is marked as terminated.
901 bool daemon = is_daemon(threadObj());
902
903 // Notify waiters on thread object. This has to be done after exit() is called
904 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
905 // group should have the destroyed bit set before waiters are notified).
906 ensure_join(this);
907 assert(!this->has_pending_exception(), "ensure_join should have cleared");
908
909 if (log_is_enabled(Debug, os, thread, timer)) {
910 _timer_exit_phase2.stop();
911 _timer_exit_phase3.start();
912 }
913 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
914 // held by this thread must be released. The spec does not distinguish
915 // between JNI-acquired and regular Java monitors. We can only see
916 // regular Java monitors here if monitor enter-exit matching is broken.
917 //
918 // ensure_join() ignores IllegalThreadStateExceptions, and so does
919 // ObjectSynchronizer::release_monitors_owned_by_thread().
920 if (exit_type == jni_detach) {
921 // Sanity check even though JNI DetachCurrentThread() would have
922 // returned JNI_ERR if there was a Java frame. JavaThread exit
923 // should be done executing Java code by the time we get here.
924 assert(!this->has_last_Java_frame(),
925 "should not have a Java frame when detaching or exiting");
926 ObjectSynchronizer::release_monitors_owned_by_thread(this);
927 assert(!this->has_pending_exception(), "release_monitors should have cleared");
928 }
929
930 // These things needs to be done while we are still a Java Thread. Make sure that thread
931 // is in a consistent state, in case GC happens
932 JFR_ONLY(Jfr::on_thread_exit(this);)
933
934 if (active_handles() != nullptr) {
935 JNIHandleBlock* block = active_handles();
936 set_active_handles(nullptr);
937 JNIHandleBlock::release_block(block);
938 }
939
940 if (free_handle_block() != nullptr) {
941 JNIHandleBlock* block = free_handle_block();
942 set_free_handle_block(nullptr);
943 JNIHandleBlock::release_block(block);
944 }
945
946 // These have to be removed while this is still a valid thread.
947 _stack_overflow_state.remove_stack_guard_pages();
948
949 if (UseTLAB) {
950 retire_tlab();
951 }
952
953 if (JvmtiEnv::environments_might_exist()) {
954 JvmtiExport::cleanup_thread(this);
955 }
956
957 // We need to cache the thread name for logging purposes below as once
958 // we have called on_thread_detach this thread must not access any oops.
959 char* thread_name = nullptr;
960 if (log_is_enabled(Debug, os, thread, timer)) {
961 ResourceMark rm(this);
962 thread_name = os::strdup(name());
963 }
964
965 if (log_is_enabled(Info, os, thread)) {
966 ResourceMark rm(this);
967 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
968 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
969 name(), os::current_thread_id());
970 }
971
972 if (log_is_enabled(Debug, os, thread, timer)) {
973 _timer_exit_phase3.stop();
974 _timer_exit_phase4.start();
975 }
976
977 #if INCLUDE_JVMCI
978 if (JVMCICounterSize > 0) {
979 if (jvmci_counters_include(this)) {
980 for (int i = 0; i < JVMCICounterSize; i++) {
981 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
982 }
983 }
984 }
985 #endif // INCLUDE_JVMCI
986
987 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
988 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
989 Threads::remove(this, daemon);
990
991 if (log_is_enabled(Debug, os, thread, timer)) {
992 _timer_exit_phase4.stop();
993 log_debug(os, thread, timer)("name='%s'"
994 ", exit-phase1=" JLONG_FORMAT
995 ", exit-phase2=" JLONG_FORMAT
996 ", exit-phase3=" JLONG_FORMAT
997 ", exit-phase4=" JLONG_FORMAT,
998 thread_name,
999 _timer_exit_phase1.milliseconds(),
1000 _timer_exit_phase2.milliseconds(),
1001 _timer_exit_phase3.milliseconds(),
1002 _timer_exit_phase4.milliseconds());
1003 os::free(thread_name);
1004 }
1005 }
1006
1007 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1008 if (active_handles() != nullptr) {
1009 JNIHandleBlock* block = active_handles();
1010 set_active_handles(nullptr);
1011 JNIHandleBlock::release_block(block);
1012 }
1013
1014 if (free_handle_block() != nullptr) {
1015 JNIHandleBlock* block = free_handle_block();
1016 set_free_handle_block(nullptr);
1017 JNIHandleBlock::release_block(block);
1018 }
1019
1020 // These have to be removed while this is still a valid thread.
1021 _stack_overflow_state.remove_stack_guard_pages();
1022
1023 if (UseTLAB) {
1024 retire_tlab();
1025 }
1026
1027 Threads::remove(this, is_daemon);
1028 }
1029
1030 JavaThread* JavaThread::active() {
1031 Thread* thread = Thread::current();
1032 if (thread->is_Java_thread()) {
1033 return JavaThread::cast(thread);
1034 } else {
1035 assert(thread->is_VM_thread(), "this must be a vm thread");
1036 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1037 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1038 return ret;
1039 }
1040 }
1041
1042 oop JavaThread::exception_oop() const {
1043 return AtomicAccess::load(&_exception_oop);
1044 }
1045
1046 void JavaThread::set_exception_oop(oop o) {
1047 AtomicAccess::store(&_exception_oop, o);
1048 }
1049
1050 void JavaThread::handle_special_runtime_exit_condition() {
1051 if (is_obj_deopt_suspend()) {
1052 frame_anchor()->make_walkable();
1053 wait_for_object_deoptimization();
1054 }
1055 }
1056
1057
1058 // Asynchronous exceptions support
1059 //
1060 void JavaThread::handle_async_exception(oop java_throwable) {
1061 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1062 assert(!is_at_poll_safepoint(), "should have never called this method");
1063
1064 if (has_last_Java_frame()) {
1065 frame f = last_frame();
1066 if (f.is_runtime_frame()) {
1067 // If the topmost frame is a runtime stub, then we are calling into
1068 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1069 // must deoptimize the caller before continuing, as the compiled exception
1070 // handler table may not be valid.
1071 RegisterMap reg_map(this,
1072 RegisterMap::UpdateMap::skip,
1073 RegisterMap::ProcessFrames::include,
1074 RegisterMap::WalkContinuation::skip);
1075 frame compiled_frame = f.sender(®_map);
1076 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1077 Deoptimization::deoptimize(this, compiled_frame);
1078 }
1079 }
1080 }
1081
1082 // We cannot call Exceptions::_throw(...) here because we cannot block
1083 set_pending_exception(java_throwable, __FILE__, __LINE__);
1084
1085 clear_scopedValueBindings();
1086
1087 LogTarget(Info, exceptions) lt;
1088 if (lt.is_enabled()) {
1089 ResourceMark rm;
1090 LogStream ls(lt);
1091 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1092 if (has_last_Java_frame()) {
1093 frame f = last_frame();
1094 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1095 }
1096 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1097 }
1098 }
1099
1100 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1101 // Do not throw asynchronous exceptions against the compiler thread
1102 // or if the thread is already exiting.
1103 if (!can_call_java() || is_exiting()) {
1104 delete aehc;
1105 return;
1106 }
1107
1108 oop exception = aehc->exception();
1109 Handshake::execute(aehc, this); // Install asynchronous handshake
1110
1111 ResourceMark rm;
1112 if (log_is_enabled(Info, exceptions)) {
1113 log_info(exceptions)("Pending Async. exception installed of type: %s",
1114 exception->klass()->external_name());
1115 }
1116 // for AbortVMOnException flag
1117 Exceptions::debug_check_abort(exception->klass()->external_name());
1118
1119 oop vt_oop = vthread();
1120 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1121 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1122 this->interrupt();
1123 }
1124 }
1125
1126 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1127 AsyncExceptionHandshakeClosure* _aehc;
1128 public:
1129 InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1130 HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1131 ~InstallAsyncExceptionHandshakeClosure() {
1132 // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1133 delete _aehc;
1134 }
1135 void do_thread(Thread* thr) {
1136 JavaThread* target = JavaThread::cast(thr);
1137 target->install_async_exception(_aehc);
1138 _aehc = nullptr;
1139 }
1140 };
1141
1142 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1143 OopHandle e(Universe::vm_global(), java_throwable);
1144 InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1145 Handshake::execute(&iaeh, target);
1146 }
1147
1148 #if INCLUDE_JVMTI
1149 void JavaThread::set_is_in_VTMS_transition(bool val) {
1150 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1151 _is_in_VTMS_transition = val;
1152 }
1153
1154 #ifdef ASSERT
1155 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1156 _is_VTMS_transition_disabler = val;
1157 }
1158 #endif
1159 #endif
1160
1161 // External suspension mechanism.
1162 //
1163 // Guarantees on return (for a valid target thread):
1164 // - Target thread will not execute any new bytecode.
1165 // - Target thread will not enter any new monitors.
1166 //
1167 bool JavaThread::java_suspend(bool register_vthread_SR) {
1168 #if INCLUDE_JVMTI
1169 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1170 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1171 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1172 #endif
1173
1174 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1175 "target JavaThread is not protected in calling context.");
1176 return this->suspend_resume_manager()->suspend(register_vthread_SR);
1177 }
1178
1179 bool JavaThread::java_resume(bool register_vthread_SR) {
1180 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1181 "missing ThreadsListHandle in calling context.");
1182 return this->suspend_resume_manager()->resume(register_vthread_SR);
1183 }
1184
1185 // Wait for another thread to perform object reallocation and relocking on behalf of
1186 // this thread. The current thread is required to change to _thread_blocked in order
1187 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1188 // handshake safe, the other thread can complete the handshake used to synchronize
1189 // with this thread and then perform the reallocation and relocking.
1190 // See EscapeBarrier::sync_and_suspend_*()
1191
1192 void JavaThread::wait_for_object_deoptimization() {
1193 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1194 assert(this == Thread::current(), "invariant");
1195
1196 bool spin_wait = os::is_MP();
1197 do {
1198 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1199 // Wait for object deoptimization if requested.
1200 if (spin_wait) {
1201 // A single deoptimization is typically very short. Microbenchmarks
1202 // showed 5% better performance when spinning.
1203 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1204 SpinYield spin(spin_limit);
1205 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1206 spin.wait();
1207 }
1208 // Spin just once
1209 spin_wait = false;
1210 } else {
1211 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1212 if (is_obj_deopt_suspend()) {
1213 ml.wait();
1214 }
1215 }
1216 // A handshake for obj. deoptimization suspend could have been processed so
1217 // we must check after processing.
1218 } while (is_obj_deopt_suspend());
1219 }
1220
1221 #ifdef ASSERT
1222 // Verify the JavaThread has not yet been published in the Threads::list, and
1223 // hence doesn't need protection from concurrent access at this stage.
1224 void JavaThread::verify_not_published() {
1225 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1226 // since an unpublished JavaThread doesn't participate in the
1227 // Thread-SMR protocol for keeping a ThreadsList alive.
1228 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1229 }
1230 #endif
1231
1232 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1233 // pending, when _suspend_flags is non-zero or when we need to process a stack
1234 // watermark. Also check for pending async exceptions (except unsafe access error).
1235 // Note only the native==>Java barriers can call this function when thread state
1236 // is _thread_in_native_trans.
1237 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1238 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1239 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1240
1241 thread->set_thread_state(_thread_in_vm);
1242
1243 // Enable WXWrite: called directly from interpreter native wrapper.
1244 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1245
1246 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1247
1248 // After returning from native, it could be that the stack frames are not
1249 // yet safe to use. We catch such situations in the subsequent stack watermark
1250 // barrier, which will trap unsafe stack frames.
1251 StackWatermarkSet::before_unwind(thread);
1252 }
1253
1254 #ifndef PRODUCT
1255 // Deoptimization
1256 // Function for testing deoptimization
1257 void JavaThread::deoptimize() {
1258 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1259 bool deopt = false; // Dump stack only if a deopt actually happens.
1260 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1261 // Iterate over all frames in the thread and deoptimize
1262 for (; !fst.is_done(); fst.next()) {
1263 if (fst.current()->can_be_deoptimized()) {
1264
1265 if (only_at) {
1266 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1267 // consists of comma or carriage return separated numbers so
1268 // search for the current bci in that string.
1269 address pc = fst.current()->pc();
1270 nmethod* nm = fst.current()->cb()->as_nmethod();
1271 ScopeDesc* sd = nm->scope_desc_at(pc);
1272 char buffer[8];
1273 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1274 size_t len = strlen(buffer);
1275 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1276 while (found != nullptr) {
1277 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1278 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1279 // Check that the bci found is bracketed by terminators.
1280 break;
1281 }
1282 found = strstr(found + 1, buffer);
1283 }
1284 if (!found) {
1285 continue;
1286 }
1287 }
1288
1289 if (DebugDeoptimization && !deopt) {
1290 deopt = true; // One-time only print before deopt
1291 tty->print_cr("[BEFORE Deoptimization]");
1292 trace_frames();
1293 trace_stack();
1294 }
1295 Deoptimization::deoptimize(this, *fst.current());
1296 }
1297 }
1298
1299 if (DebugDeoptimization && deopt) {
1300 tty->print_cr("[AFTER Deoptimization]");
1301 trace_frames();
1302 }
1303 }
1304
1305
1306 // Make zombies
1307 void JavaThread::make_zombies() {
1308 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1309 if (fst.current()->can_be_deoptimized()) {
1310 // it is a Java nmethod
1311 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1312 assert(nm != nullptr, "did not find nmethod");
1313 nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1314 }
1315 }
1316 }
1317 #endif // PRODUCT
1318
1319
1320 void JavaThread::deoptimize_marked_methods() {
1321 if (!has_last_Java_frame()) return;
1322 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1323 for (; !fst.is_done(); fst.next()) {
1324 if (fst.current()->should_be_deoptimized()) {
1325 Deoptimization::deoptimize(this, *fst.current());
1326 }
1327 }
1328 }
1329
1330 #ifdef ASSERT
1331 void JavaThread::verify_frame_info() {
1332 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1333 (has_last_Java_frame() && java_call_counter() > 0),
1334 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1335 has_last_Java_frame() ? "true" : "false", java_call_counter());
1336 }
1337 #endif
1338
1339 // Push on a new block of JNI handles.
1340 void JavaThread::push_jni_handle_block() {
1341 // Allocate a new block for JNI handles.
1342 // Inlined code from jni_PushLocalFrame()
1343 JNIHandleBlock* old_handles = active_handles();
1344 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1345 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1346 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1347 set_active_handles(new_handles);
1348 }
1349
1350 // Pop off the current block of JNI handles.
1351 void JavaThread::pop_jni_handle_block() {
1352 // Release our JNI handle block
1353 JNIHandleBlock* old_handles = active_handles();
1354 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1355 assert(new_handles != nullptr, "should never set active handles to null");
1356 set_active_handles(new_handles);
1357 old_handles->set_pop_frame_link(nullptr);
1358 JNIHandleBlock::release_block(old_handles, this);
1359 }
1360
1361 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1362 // Verify that the deferred card marks have been flushed.
1363 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1364
1365 // Traverse the GCHandles
1366 Thread::oops_do_no_frames(f, cf);
1367
1368 if (active_handles() != nullptr) {
1369 active_handles()->oops_do(f);
1370 }
1371
1372 DEBUG_ONLY(verify_frame_info();)
1373
1374 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1375 // If we have deferred set_locals there might be oops waiting to be
1376 // written
1377 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1378 if (list != nullptr) {
1379 for (int i = 0; i < list->length(); i++) {
1380 list->at(i)->oops_do(f);
1381 }
1382 }
1383
1384 // Traverse instance variables at the end since the GC may be moving things
1385 // around using this function
1386 f->do_oop((oop*) &_vm_result_oop);
1387 f->do_oop((oop*) &_exception_oop);
1388 #if INCLUDE_JVMCI
1389 f->do_oop((oop*) &_jvmci_reserved_oop0);
1390
1391 if (_live_nmethod != nullptr && cf != nullptr) {
1392 cf->do_nmethod(_live_nmethod);
1393 }
1394 #endif
1395
1396 if (jvmti_thread_state() != nullptr) {
1397 jvmti_thread_state()->oops_do(f, cf);
1398 }
1399
1400 // The continuation oops are really on the stack. But there is typically at most
1401 // one of those per thread, so we handle them here in the oops_do_no_frames part
1402 // so that we don't have to sprinkle as many stack watermark checks where these
1403 // oops are used. We just need to make sure the thread has started processing.
1404 ContinuationEntry* entry = _cont_entry;
1405 while (entry != nullptr) {
1406 f->do_oop((oop*)entry->cont_addr());
1407 f->do_oop((oop*)entry->chunk_addr());
1408 entry = entry->parent();
1409 }
1410
1411 // Due to lightweight locking
1412 lock_stack().oops_do(f);
1413 }
1414
1415 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1416 if (!has_last_Java_frame()) {
1417 return;
1418 }
1419 // Finish any pending lazy GC activity for the frames
1420 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1421 // Traverse the execution stack
1422 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1423 fst.current()->oops_do(f, cf, fst.register_map());
1424 }
1425 }
1426
1427 #ifdef ASSERT
1428 void JavaThread::verify_states_for_handshake() {
1429 // This checks that the thread has a correct frame state during a handshake.
1430 verify_frame_info();
1431 }
1432 #endif
1433
1434 void JavaThread::nmethods_do(NMethodClosure* cf) {
1435 DEBUG_ONLY(verify_frame_info();)
1436 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1437
1438 if (has_last_Java_frame()) {
1439 // Traverse the execution stack
1440 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1441 fst.current()->nmethod_do(cf);
1442 }
1443 }
1444
1445 if (jvmti_thread_state() != nullptr) {
1446 jvmti_thread_state()->nmethods_do(cf);
1447 }
1448
1449 #if INCLUDE_JVMCI
1450 if (_live_nmethod != nullptr) {
1451 cf->do_nmethod(_live_nmethod);
1452 }
1453 #endif
1454 }
1455
1456 void JavaThread::metadata_do(MetadataClosure* f) {
1457 if (has_last_Java_frame()) {
1458 // Traverse the execution stack to call f() on the methods in the stack
1459 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1460 fst.current()->metadata_do(f);
1461 }
1462 } else if (is_Compiler_thread()) {
1463 // need to walk ciMetadata in current compile tasks to keep alive.
1464 CompilerThread* ct = (CompilerThread*)this;
1465 if (ct->env() != nullptr) {
1466 ct->env()->metadata_do(f);
1467 }
1468 CompileTask* task = ct->task();
1469 if (task != nullptr) {
1470 task->metadata_do(f);
1471 }
1472 }
1473 }
1474
1475 // Printing
1476 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1477 switch (_thread_state) {
1478 case _thread_uninitialized: return "_thread_uninitialized";
1479 case _thread_new: return "_thread_new";
1480 case _thread_new_trans: return "_thread_new_trans";
1481 case _thread_in_native: return "_thread_in_native";
1482 case _thread_in_native_trans: return "_thread_in_native_trans";
1483 case _thread_in_vm: return "_thread_in_vm";
1484 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1485 case _thread_in_Java: return "_thread_in_Java";
1486 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1487 case _thread_blocked: return "_thread_blocked";
1488 case _thread_blocked_trans: return "_thread_blocked_trans";
1489 default: return "unknown thread state";
1490 }
1491 }
1492
1493 void JavaThread::print_thread_state_on(outputStream *st) const {
1494 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1495 }
1496
1497 // Called by Threads::print() for VM_PrintThreads operation
1498 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1499 st->print_raw("\"");
1500 st->print_raw(name());
1501 st->print_raw("\" ");
1502 oop thread_oop = threadObj();
1503 if (thread_oop != nullptr) {
1504 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1505 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1506 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1507 }
1508 Thread::print_on(st, print_extended_info);
1509 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1510 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1511 if (thread_oop != nullptr) {
1512 if (is_vthread_mounted()) {
1513 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1514 } else {
1515 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1516 }
1517 }
1518 #ifndef PRODUCT
1519 _safepoint_state->print_on(st);
1520 #endif // PRODUCT
1521 if (is_Compiler_thread()) {
1522 CompileTask *task = ((CompilerThread*)this)->task();
1523 if (task != nullptr) {
1524 st->print(" Compiling: ");
1525 task->print(st, nullptr, true, false);
1526 } else {
1527 st->print(" No compile task");
1528 }
1529 st->cr();
1530 }
1531 }
1532
1533 void JavaThread::print() const { print_on(tty); }
1534
1535 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1536 st->print("%s", get_thread_name_string(buf, buflen));
1537 }
1538
1539 // Called by fatal error handler. The difference between this and
1540 // JavaThread::print() is that we can't grab lock or allocate memory.
1541 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1542 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1543 Thread* current = Thread::current_or_null_safe();
1544 assert(current != nullptr, "cannot be called by a detached thread");
1545 st->fill_to(60);
1546 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1547 // Only access threadObj() if current thread is not a JavaThread
1548 // or if it is a JavaThread that can safely access oops.
1549 oop thread_obj = threadObj();
1550 if (thread_obj != nullptr) {
1551 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1552 }
1553 }
1554 st->print(" [");
1555 st->print("%s", _get_thread_state_name(_thread_state));
1556 if (osthread()) {
1557 st->print(", id=%d", osthread()->thread_id());
1558 }
1559 // Use raw field members for stack base/size as this could be
1560 // called before a thread has run enough to initialize them.
1561 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1562 p2i(_stack_base - _stack_size), p2i(_stack_base),
1563 PROPERFMTARGS(_stack_size));
1564 st->print("]");
1565
1566 ThreadsSMRSupport::print_info_on(this, st);
1567 return;
1568 }
1569
1570
1571 // Verification
1572
1573 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1574 // ignore if there is no stack
1575 if (!has_last_Java_frame()) return;
1576 // traverse the stack frames. Starts from top frame.
1577 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1578 frame* fr = fst.current();
1579 f(fr, fst.register_map());
1580 }
1581 }
1582
1583 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1584
1585 void JavaThread::verify() {
1586 // Verify oops in the thread.
1587 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1588
1589 // Verify the stack frames.
1590 frames_do(frame_verify);
1591 }
1592
1593 // CR 6300358 (sub-CR 2137150)
1594 // Most callers of this method assume that it can't return null but a
1595 // thread may not have a name whilst it is in the process of attaching to
1596 // the VM - see CR 6412693, and there are places where a JavaThread can be
1597 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1598 // if vm exit occurs during initialization). These cases can all be accounted
1599 // for such that this method never returns null.
1600 const char* JavaThread::name() const {
1601 if (Thread::is_JavaThread_protected(/* target */ this)) {
1602 // The target JavaThread is protected so get_thread_name_string() is safe:
1603 return get_thread_name_string();
1604 }
1605
1606 // The target JavaThread is not protected so we return the default:
1607 return Thread::name();
1608 }
1609
1610 // Like name() but doesn't include the protection check. This must only be
1611 // called when it is known to be safe, even though the protection check can't tell
1612 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1613 const char* JavaThread::name_raw() const {
1614 return get_thread_name_string();
1615 }
1616
1617 // Returns a non-null representation of this thread's name, or a suitable
1618 // descriptive string if there is no set name.
1619 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1620 const char* name_str;
1621 #ifdef ASSERT
1622 Thread* current = Thread::current_or_null_safe();
1623 assert(current != nullptr, "cannot be called by a detached thread");
1624 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1625 // Only access threadObj() if current thread is not a JavaThread
1626 // or if it is a JavaThread that can safely access oops.
1627 #endif
1628 oop thread_obj = threadObj();
1629 if (thread_obj != nullptr) {
1630 oop name = java_lang_Thread::name(thread_obj);
1631 if (name != nullptr) {
1632 if (buf == nullptr) {
1633 name_str = java_lang_String::as_utf8_string(name);
1634 } else {
1635 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1636 }
1637 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1638 name_str = "<no-name - thread is attaching>";
1639 } else {
1640 name_str = "<un-named>";
1641 }
1642 } else {
1643 name_str = Thread::name();
1644 }
1645 #ifdef ASSERT
1646 } else {
1647 // Current JavaThread has exited...
1648 if (current == this) {
1649 // ... and is asking about itself:
1650 name_str = "<no-name - current JavaThread has exited>";
1651 } else {
1652 // ... and it can't safely determine this JavaThread's name so
1653 // use the default thread name.
1654 name_str = Thread::name();
1655 }
1656 }
1657 #endif
1658 assert(name_str != nullptr, "unexpected null thread name");
1659 return name_str;
1660 }
1661
1662 // Helper to extract the name from the thread oop for logging.
1663 const char* JavaThread::name_for(oop thread_obj) {
1664 assert(thread_obj != nullptr, "precondition");
1665 oop name = java_lang_Thread::name(thread_obj);
1666 const char* name_str;
1667 if (name != nullptr) {
1668 name_str = java_lang_String::as_utf8_string(name);
1669 } else {
1670 name_str = "<un-named>";
1671 }
1672 return name_str;
1673 }
1674
1675 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1676
1677 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1678 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1679 // Link Java Thread object <-> C++ Thread
1680
1681 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1682 // and put it into a new Handle. The Handle "thread_oop" can then
1683 // be used to pass the C++ thread object to other methods.
1684
1685 // Set the Java level thread object (jthread) field of the
1686 // new thread (a JavaThread *) to C++ thread object using the
1687 // "thread_oop" handle.
1688
1689 // Set the thread field (a JavaThread *) of the
1690 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1691
1692 Handle thread_oop(Thread::current(),
1693 JNIHandles::resolve_non_null(jni_thread));
1694 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1695 "must be initialized");
1696 set_threadOopHandles(thread_oop());
1697 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1698
1699 if (prio == NoPriority) {
1700 prio = java_lang_Thread::priority(thread_oop());
1701 assert(prio != NoPriority, "A valid priority should be present");
1702 }
1703
1704 // Push the Java priority down to the native thread; needs Threads_lock
1705 Thread::set_priority(this, prio);
1706
1707 // Add the new thread to the Threads list and set it in motion.
1708 // We must have threads lock in order to call Threads::add.
1709 // It is crucial that we do not block before the thread is
1710 // added to the Threads list for if a GC happens, then the java_thread oop
1711 // will not be visited by GC.
1712 Threads::add(this);
1713 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1714 // on a ThreadsList. We don't want to wait for the release when the
1715 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1716 // is already visible to JVM/TI via the ThreadsList.
1717 java_lang_Thread::release_set_thread(thread_oop(), this);
1718 }
1719
1720 oop JavaThread::current_park_blocker() {
1721 // Support for JSR-166 locks
1722 oop thread_oop = threadObj();
1723 if (thread_oop != nullptr) {
1724 return java_lang_Thread::park_blocker(thread_oop);
1725 }
1726 return nullptr;
1727 }
1728
1729 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1730 // This is the external format, selecting the platform or vthread
1731 // as applicable, and allowing for a native-only stack.
1732 void JavaThread::print_jni_stack() {
1733 assert(this == JavaThread::current(), "Can't print stack of other threads");
1734 if (!has_last_Java_frame()) {
1735 ResourceMark rm(this);
1736 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1737 if (buf == nullptr) {
1738 tty->print_cr("Unable to print native stack - out of memory");
1739 return;
1740 }
1741 NativeStackPrinter nsp(this);
1742 address lastpc = nullptr;
1743 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1744 true /*print_source_info */, -1 /* max stack */ );
1745 } else {
1746 print_active_stack_on(tty);
1747 }
1748 }
1749
1750 void JavaThread::print_stack_on(outputStream* st) {
1751 if (!has_last_Java_frame()) return;
1752
1753 Thread* current_thread = Thread::current();
1754 ResourceMark rm(current_thread);
1755 HandleMark hm(current_thread);
1756
1757 RegisterMap reg_map(this,
1758 RegisterMap::UpdateMap::include,
1759 RegisterMap::ProcessFrames::include,
1760 RegisterMap::WalkContinuation::skip);
1761 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1762 int count = 0;
1763 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1764 if (f->is_java_frame()) {
1765 javaVFrame* jvf = javaVFrame::cast(f);
1766 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1767
1768 // Print out lock information
1769 if (JavaMonitorsInStackTrace) {
1770 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1771 }
1772 } else {
1773 // Ignore non-Java frames
1774 }
1775
1776 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1777 count++;
1778 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1779 }
1780 }
1781
1782 void JavaThread::print_vthread_stack_on(outputStream* st) {
1783 assert(is_vthread_mounted(), "Caller should have checked this");
1784 assert(has_last_Java_frame(), "must be");
1785
1786 Thread* current_thread = Thread::current();
1787 ResourceMark rm(current_thread);
1788 HandleMark hm(current_thread);
1789
1790 RegisterMap reg_map(this,
1791 RegisterMap::UpdateMap::include,
1792 RegisterMap::ProcessFrames::include,
1793 RegisterMap::WalkContinuation::include);
1794 ContinuationEntry* cont_entry = last_continuation();
1795 vframe* start_vf = last_java_vframe(®_map);
1796 int count = 0;
1797 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1798 // Watch for end of vthread stack
1799 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1800 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1801 if (cont_entry->is_virtual_thread()) {
1802 break;
1803 }
1804 cont_entry = cont_entry->parent();
1805 }
1806 if (f->is_java_frame()) {
1807 javaVFrame* jvf = javaVFrame::cast(f);
1808 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1809
1810 // Print out lock information
1811 if (JavaMonitorsInStackTrace) {
1812 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1813 }
1814 } else {
1815 // Ignore non-Java frames
1816 }
1817
1818 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1819 count++;
1820 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1821 }
1822 }
1823
1824 void JavaThread::print_active_stack_on(outputStream* st) {
1825 if (is_vthread_mounted()) {
1826 print_vthread_stack_on(st);
1827 } else {
1828 print_stack_on(st);
1829 }
1830 }
1831
1832 #if INCLUDE_JVMTI
1833 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1834 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1835 set_jvmti_vthread(thread_oop);
1836
1837 // unbind current JvmtiThreadState from JavaThread
1838 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1839
1840 // bind new JvmtiThreadState to JavaThread
1841 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1842
1843 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1844 JvmtiThreadState::process_pending_interp_only(this);
1845
1846 return jvmti_thread_state();
1847 }
1848 #endif
1849
1850 // JVMTI PopFrame support
1851 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1852 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1853 if (in_bytes(size_in_bytes) != 0) {
1854 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1855 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1856 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1857 }
1858 }
1859
1860 void* JavaThread::popframe_preserved_args() {
1861 return _popframe_preserved_args;
1862 }
1863
1864 ByteSize JavaThread::popframe_preserved_args_size() {
1865 return in_ByteSize(_popframe_preserved_args_size);
1866 }
1867
1868 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1869 int sz = in_bytes(popframe_preserved_args_size());
1870 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1871 return in_WordSize(sz / wordSize);
1872 }
1873
1874 void JavaThread::popframe_free_preserved_args() {
1875 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1876 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1877 _popframe_preserved_args = nullptr;
1878 _popframe_preserved_args_size = 0;
1879 }
1880
1881 #ifndef PRODUCT
1882
1883 void JavaThread::trace_frames() {
1884 tty->print_cr("[Describe stack]");
1885 int frame_no = 1;
1886 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1887 tty->print(" %d. ", frame_no++);
1888 fst.current()->print_value_on(tty);
1889 tty->cr();
1890 }
1891 }
1892
1893 class PrintAndVerifyOopClosure: public OopClosure {
1894 protected:
1895 template <class T> inline void do_oop_work(T* p) {
1896 oop obj = RawAccess<>::oop_load(p);
1897 if (obj == nullptr) return;
1898 tty->print(INTPTR_FORMAT ": ", p2i(p));
1899 if (oopDesc::is_oop_or_null(obj)) {
1900 if (obj->is_objArray()) {
1901 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1902 } else {
1903 obj->print();
1904 }
1905 } else {
1906 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1907 }
1908 tty->cr();
1909 }
1910 public:
1911 virtual void do_oop(oop* p) { do_oop_work(p); }
1912 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1913 };
1914
1915 #ifdef ASSERT
1916 // Print or validate the layout of stack frames
1917 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1918 ResourceMark rm;
1919 PreserveExceptionMark pm(this);
1920 FrameValues values;
1921 int frame_no = 0;
1922 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1923 fst.current()->describe(values, ++frame_no, fst.register_map());
1924 if (depth == frame_no) break;
1925 }
1926 Continuation::describe(values);
1927 if (validate_only) {
1928 values.validate();
1929 } else {
1930 tty->print_cr("[Describe stack layout]");
1931 values.print(this);
1932 }
1933 }
1934 #endif
1935
1936 void JavaThread::trace_stack_from(vframe* start_vf) {
1937 ResourceMark rm;
1938 int vframe_no = 1;
1939 for (vframe* f = start_vf; f; f = f->sender()) {
1940 if (f->is_java_frame()) {
1941 javaVFrame::cast(f)->print_activation(vframe_no++);
1942 } else {
1943 f->print();
1944 }
1945 if (vframe_no > StackPrintLimit) {
1946 tty->print_cr("...<more frames>...");
1947 return;
1948 }
1949 }
1950 }
1951
1952
1953 void JavaThread::trace_stack() {
1954 if (!has_last_Java_frame()) return;
1955 Thread* current_thread = Thread::current();
1956 ResourceMark rm(current_thread);
1957 HandleMark hm(current_thread);
1958 RegisterMap reg_map(this,
1959 RegisterMap::UpdateMap::include,
1960 RegisterMap::ProcessFrames::include,
1961 RegisterMap::WalkContinuation::skip);
1962 trace_stack_from(last_java_vframe(®_map));
1963 }
1964
1965
1966 #endif // PRODUCT
1967
1968 frame JavaThread::vthread_last_frame() {
1969 assert (is_vthread_mounted(), "Virtual thread not mounted");
1970 return last_frame();
1971 }
1972
1973 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1974 const ContinuationEntry* entry = vthread_continuation();
1975 guarantee (entry != nullptr, "Not a carrier thread");
1976 frame f = entry->to_frame();
1977 if (reg_map->process_frames()) {
1978 entry->flush_stack_processing(this);
1979 }
1980 entry->update_register_map(reg_map);
1981 return f.sender(reg_map);
1982 }
1983
1984 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1985 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1986 }
1987
1988 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
1989 assert(reg_map != nullptr, "a map must be given");
1990 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
1991 if (vf->is_java_frame()) return javaVFrame::cast(vf);
1992 }
1993 return nullptr;
1994 }
1995
1996 Klass* JavaThread::security_get_caller_class(int depth) {
1997 ResetNoHandleMark rnhm;
1998 HandleMark hm(Thread::current());
1999
2000 vframeStream vfst(this);
2001 vfst.security_get_caller_frame(depth);
2002 if (!vfst.at_end()) {
2003 return vfst.method()->method_holder();
2004 }
2005 return nullptr;
2006 }
2007
2008 // Internal convenience function for millisecond resolution sleeps.
2009 bool JavaThread::sleep(jlong millis) {
2010 jlong nanos;
2011 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2012 // Conversion to nanos would overflow, saturate at max
2013 nanos = max_jlong;
2014 } else {
2015 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2016 }
2017 return sleep_nanos(nanos);
2018 }
2019
2020 // java.lang.Thread.sleep support
2021 // Returns true if sleep time elapsed as expected, and false
2022 // if the thread was interrupted or async exception was installed.
2023 bool JavaThread::sleep_nanos(jlong nanos) {
2024 assert(this == Thread::current(), "thread consistency check");
2025 assert(nanos >= 0, "nanos are in range");
2026
2027 ParkEvent * const slp = this->_SleepEvent;
2028 // Because there can be races with thread interruption sending an unpark()
2029 // to the event, we explicitly reset it here to avoid an immediate return.
2030 // The actual interrupt state will be checked before we park().
2031 slp->reset();
2032 // Thread interruption establishes a happens-before ordering in the
2033 // Java Memory Model, so we need to ensure we synchronize with the
2034 // interrupt state.
2035 OrderAccess::fence();
2036
2037 jlong prevtime = os::javaTimeNanos();
2038
2039 jlong nanos_remaining = nanos;
2040
2041 for (;;) {
2042 if (has_async_exception_condition()) {
2043 return false;
2044 }
2045 // interruption has precedence over timing out
2046 if (this->is_interrupted(true)) {
2047 return false;
2048 }
2049
2050 if (nanos_remaining <= 0) {
2051 return true;
2052 }
2053
2054 {
2055 ThreadBlockInVM tbivm(this);
2056 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2057 slp->park_nanos(nanos_remaining);
2058 }
2059
2060 // Update elapsed time tracking
2061 jlong newtime = os::javaTimeNanos();
2062 if (newtime - prevtime < 0) {
2063 // time moving backwards, should only happen if no monotonic clock
2064 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2065 assert(false,
2066 "unexpected time moving backwards detected in JavaThread::sleep()");
2067 } else {
2068 nanos_remaining -= (newtime - prevtime);
2069 }
2070 prevtime = newtime;
2071 }
2072 }
2073
2074 // Last thread running calls java.lang.Shutdown.shutdown()
2075 void JavaThread::invoke_shutdown_hooks() {
2076 HandleMark hm(this);
2077
2078 // We could get here with a pending exception, if so clear it now.
2079 if (this->has_pending_exception()) {
2080 this->clear_pending_exception();
2081 }
2082
2083 EXCEPTION_MARK;
2084 Klass* shutdown_klass =
2085 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2086 THREAD);
2087 if (shutdown_klass != nullptr) {
2088 // SystemDictionary::resolve_or_null will return null if there was
2089 // an exception. If we cannot load the Shutdown class, just don't
2090 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2091 // won't be run. Note that if a shutdown hook was registered,
2092 // the Shutdown class would have already been loaded
2093 // (Runtime.addShutdownHook will load it).
2094 JavaValue result(T_VOID);
2095 JavaCalls::call_static(&result,
2096 shutdown_klass,
2097 vmSymbols::shutdown_name(),
2098 vmSymbols::void_method_signature(),
2099 THREAD);
2100 }
2101 CLEAR_PENDING_EXCEPTION;
2102 }
2103
2104 #ifndef PRODUCT
2105 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2106 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2107 }
2108 #endif
2109
2110 // Helper function to create the java.lang.Thread object for a
2111 // VM-internal thread. The thread will have the given name, and be
2112 // a member of the "system" ThreadGroup.
2113 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2114 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2115
2116 // Initialize thread_oop to put it into the system threadGroup.
2117 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2118 Handle thread_group(THREAD, Universe::system_thread_group());
2119 Handle thread_oop =
2120 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2121 vmSymbols::threadgroup_string_void_signature(),
2122 thread_group,
2123 string,
2124 CHECK_NH);
2125
2126 return thread_oop;
2127 }
2128
2129 // Starts the target JavaThread as a daemon of the given priority, and
2130 // bound to the given java.lang.Thread instance.
2131 // The Threads_lock is held for the duration.
2132 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2133 Handle thread_oop, ThreadPriority prio) {
2134
2135 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2136
2137 MutexLocker mu(current, Threads_lock);
2138
2139 // Initialize the fields of the thread_oop first.
2140 if (prio != NoPriority) {
2141 java_lang_Thread::set_priority(thread_oop(), prio);
2142 // Note: we don't call os::set_priority here. Possibly we should,
2143 // else all threads should call it themselves when they first run.
2144 }
2145
2146 java_lang_Thread::set_daemon(thread_oop());
2147
2148 // Now bind the thread_oop to the target JavaThread.
2149 target->set_threadOopHandles(thread_oop());
2150 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2151
2152 Threads::add(target); // target is now visible for safepoint/handshake
2153 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2154 // on a ThreadsList. We don't want to wait for the release when the
2155 // Theads_lock is dropped when the 'mu' destructor is run since the
2156 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2157
2158 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2159 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2160 Thread::start(target);
2161 }
2162
2163 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2164 // At this point it may be possible that no osthread was created for the
2165 // JavaThread due to lack of resources. However, since this must work
2166 // for critical system threads just check and abort if this fails.
2167 if (thread->osthread() == nullptr) {
2168 // This isn't really an OOM condition, but historically this is what
2169 // we report.
2170 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2171 os::native_thread_creation_failed_msg());
2172 }
2173 }
2174
2175 void JavaThread::pretouch_stack() {
2176 // Given an established java thread stack with usable area followed by
2177 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2178 // from the current frame down to the start of the shadow zone.
2179 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2180 if (is_in_full_stack(end)) {
2181 char* p1 = (char*) alloca(1);
2182 address here = (address) &p1;
2183 if (is_in_full_stack(here) && here > end) {
2184 size_t to_alloc = here - end;
2185 char* p2 = (char*) alloca(to_alloc);
2186 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2187 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2188 os::pretouch_memory(p2, p2 + to_alloc,
2189 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2190 }
2191 }
2192 }
2193
2194 // Deferred OopHandle release support.
2195
2196 class OopHandleList : public CHeapObj<mtInternal> {
2197 static const int _count = 4;
2198 OopHandle _handles[_count];
2199 OopHandleList* _next;
2200 int _index;
2201 public:
2202 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2203 void add(OopHandle h) {
2204 assert(_index < _count, "too many additions");
2205 _handles[_index++] = h;
2206 }
2207 ~OopHandleList() {
2208 assert(_index == _count, "usage error");
2209 for (int i = 0; i < _index; i++) {
2210 _handles[i].release(JavaThread::thread_oop_storage());
2211 }
2212 }
2213 OopHandleList* next() const { return _next; }
2214 };
2215
2216 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2217
2218 // Called by the ServiceThread to do the work of releasing
2219 // the OopHandles.
2220 void JavaThread::release_oop_handles() {
2221 OopHandleList* list;
2222 {
2223 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2224 list = _oop_handle_list;
2225 _oop_handle_list = nullptr;
2226 }
2227 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2228
2229 while (list != nullptr) {
2230 OopHandleList* l = list;
2231 list = l->next();
2232 delete l;
2233 }
2234 }
2235
2236 // Add our OopHandles for later release.
2237 void JavaThread::add_oop_handles_for_release() {
2238 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2239 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2240 new_head->add(_threadObj);
2241 new_head->add(_vthread);
2242 new_head->add(_jvmti_vthread);
2243 new_head->add(_scopedValueCache);
2244 _oop_handle_list = new_head;
2245 Service_lock->notify_all();
2246 }
2247
2248 #if INCLUDE_JFR
2249 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2250 assert(result != freeze_ok, "sanity check");
2251 _last_freeze_fail_result = result;
2252 _last_freeze_fail_time = Ticks::now();
2253 }
2254
2255 // Post jdk.VirtualThreadPinned event
2256 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2257 assert(result != freeze_ok, "sanity check");
2258 if (event->should_commit()) {
2259 char reason[256];
2260 if (class_to_be_initialized() != nullptr) {
2261 ResourceMark rm(this);
2262 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2263 class_to_be_initialized()->external_name());
2264 event->set_pinnedReason(reason);
2265 } else if (class_being_initialized() != nullptr) {
2266 ResourceMark rm(this);
2267 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2268 class_being_initialized()->external_name());
2269 event->set_pinnedReason(reason);
2270 } else if (result == freeze_pinned_native) {
2271 event->set_pinnedReason("Native or VM frame on stack");
2272 } else {
2273 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2274 event->set_pinnedReason(reason);
2275 }
2276 event->set_blockingOperation(op);
2277 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2278 event->commit();
2279 }
2280 }
2281 #endif