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 if (!javathread->is_aot_thread()) { \
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 _throwing_unsafe_access_error(false),
448 _do_not_unlock_if_synchronized(false),
449 #if INCLUDE_JVMTI
450 _carrier_thread_suspended(false),
451 _is_disable_suspend(false),
452 _is_in_java_upcall(false),
453 _jvmti_events_disabled(0),
454 _on_monitor_waited_event(false),
455 _contended_entered_monitor(nullptr),
456 #endif
457 _jni_attach_state(_not_attaching_via_jni),
458 _is_in_internal_oome_mark(false),
459 #if INCLUDE_JVMCI
460 _pending_deoptimization(-1),
461 _pending_monitorenter(false),
462 _pending_transfer_to_interpreter(false),
463 _pending_failed_speculation(0),
464 _jvmci{nullptr},
465 _libjvmci_runtime(nullptr),
466 _jvmci_counters(nullptr),
467 _jvmci_reserved0(0),
468 _jvmci_reserved1(0),
469 _jvmci_reserved_oop0(nullptr),
470 _live_nmethod(nullptr),
471 #endif // INCLUDE_JVMCI
472
473 _exception_oop(oop()),
474 _exception_pc(nullptr),
475 _exception_handler_pc(nullptr),
476
477 _jni_active_critical(0),
478 _pending_jni_exception_check_fn(nullptr),
479 _depth_first_number(0),
480
481 // JVMTI PopFrame support
482 _popframe_condition(popframe_inactive),
483 _frames_to_pop_failed_realloc(0),
484
485 _cont_entry(nullptr),
486 _cont_fastpath(nullptr),
487 _cont_fastpath_thread_state(1),
488 _unlocked_inflated_monitor(nullptr),
489
490 _preempt_alternate_return(nullptr),
491 _preemption_cancelled(false),
492 _pending_interrupted_exception(false),
493 _at_preemptable_init(false),
494 DEBUG_ONLY(_preempt_init_klass(nullptr) COMMA)
495 DEBUG_ONLY(_interp_at_preemptable_vmcall_cnt(0) COMMA)
496 DEBUG_ONLY(_interp_redoing_vm_call(false) COMMA)
497
498 _handshake(this),
499 _suspend_resume_manager(this, &_handshake._lock),
500
501 _is_in_vthread_transition(false),
502 DEBUG_ONLY(_is_vthread_transition_disabler(false) COMMA)
503 DEBUG_ONLY(_is_disabler_at_start(false) COMMA)
504
505 _popframe_preserved_args(nullptr),
506 _popframe_preserved_args_size(0),
507
508 _jvmti_thread_state(nullptr),
509 _interp_only_mode(0),
510 _should_post_on_exceptions_flag(JNI_FALSE),
511 _thread_stat(new ThreadStatistics()),
512
513 _parker(),
514
515 _class_to_be_initialized(nullptr),
516 _class_being_initialized(nullptr),
517
518 _SleepEvent(ParkEvent::Allocate(this)),
519
520 #if INCLUDE_JFR
521 _last_freeze_fail_result(freeze_ok),
522 #endif
523
524 _lock_stack(this),
525 _om_cache(this) {
526 set_jni_functions(jni_functions());
527
528 #if INCLUDE_JVMCI
529 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
530 if (JVMCICounterSize > 0) {
531 resize_counters(0, (int) JVMCICounterSize);
532 }
533 #endif // INCLUDE_JVMCI
534
535 // Setup safepoint state info for this thread
536 ThreadSafepointState::create(this);
537
538 SafepointMechanism::initialize_header(this);
539
540 set_requires_cross_modify_fence(false);
541
542 pd_initialize();
543 }
544
545 JavaThread* JavaThread::create_attaching_thread() {
546 JavaThread* jt = new JavaThread();
547 jt->_jni_attach_state = _attaching_via_jni;
548 return jt;
549 }
550
551 // interrupt support
552
553 void JavaThread::interrupt() {
554 // All callers should have 'this' thread protected by a
555 // ThreadsListHandle so that it cannot terminate and deallocate
556 // itself.
557 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
558
559 // For Windows _interrupt_event
560 WINDOWS_ONLY(osthread()->set_interrupted(true);)
561
562 // For Thread.sleep
563 _SleepEvent->unpark();
564
565 // For JSR166 LockSupport.park
566 parker()->unpark();
567
568 // For ObjectMonitor and JvmtiRawMonitor
569 _ParkEvent->unpark();
570 }
571
572 bool JavaThread::is_interrupted(bool clear_interrupted) {
573 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
574
575 if (_threadObj.peek() == nullptr) {
576 // If there is no j.l.Thread then it is impossible to have
577 // been interrupted. We can find null during VM initialization
578 // or when a JNI thread is still in the process of attaching.
579 // In such cases this must be the current thread.
580 assert(this == Thread::current(), "invariant");
581 return false;
582 }
583
584 bool interrupted = java_lang_Thread::interrupted(threadObj());
585
586 // NOTE that since there is no "lock" around the interrupt and
587 // is_interrupted operations, there is the possibility that the
588 // interrupted flag will be "false" but that the
589 // low-level events will be in the signaled state. This is
590 // intentional. The effect of this is that Object.wait() and
591 // LockSupport.park() will appear to have a spurious wakeup, which
592 // is allowed and not harmful, and the possibility is so rare that
593 // it is not worth the added complexity to add yet another lock.
594 // For the sleep event an explicit reset is performed on entry
595 // to JavaThread::sleep, so there is no early return. It has also been
596 // recommended not to put the interrupted flag into the "event"
597 // structure because it hides the issue.
598 // Also, because there is no lock, we must only clear the interrupt
599 // state if we are going to report that we were interrupted; otherwise
600 // an interrupt that happens just after we read the field would be lost.
601 if (interrupted && clear_interrupted) {
602 assert(this == Thread::current(), "only the current thread can clear");
603 java_lang_Thread::set_interrupted(threadObj(), false);
604 WINDOWS_ONLY(osthread()->set_interrupted(false);)
605 }
606 return interrupted;
607 }
608
609 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
610 // the Java code in Object::wait which are not present in RawMonitorWait.
611 bool JavaThread::get_and_clear_interrupted() {
612 if (!is_interrupted(false)) {
613 return false;
614 }
615 oop thread_oop = vthread_or_thread();
616 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
617
618 if (!is_virtual) {
619 return is_interrupted(true);
620 }
621 // Virtual thread: clear interrupt status for both virtual and
622 // carrier threads under the interruptLock protection.
623 JavaThread* current = JavaThread::current();
624 HandleMark hm(current);
625 Handle thread_h(current, thread_oop);
626 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
627
628 // re-check the interrupt status under the interruptLock protection
629 bool interrupted = java_lang_Thread::interrupted(thread_h());
630
631 if (interrupted) {
632 assert(this == Thread::current(), "only the current thread can clear");
633 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
634 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
635 WINDOWS_ONLY(osthread()->set_interrupted(false);)
636 }
637 return interrupted;
638 }
639
640 void JavaThread::block_if_vm_exited() {
641 if (_terminated == _vm_exited) {
642 // _vm_exited is set at safepoint, and Threads_lock is never released
643 // so we will block here forever.
644 // Here we can be doing a jump from a safe state to an unsafe state without
645 // proper transition, but it happens after the final safepoint has begun so
646 // this jump won't cause any safepoint problems.
647 set_thread_state(_thread_in_vm);
648 Threads_lock->lock();
649 ShouldNotReachHere();
650 }
651 }
652
653 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
654 set_entry_point(entry_point);
655 // Create the native thread itself.
656 // %note runtime_23
657 os::ThreadType thr_type = os::java_thread;
658 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
659 os::java_thread;
660 os::create_thread(this, thr_type, stack_sz);
661 // The _osthread may be null here because we ran out of memory (too many threads active).
662 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
663 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
664 // the exception consists of creating the exception object & initializing it, initialization
665 // will leave the VM via a JavaCall and then all locks must be unlocked).
666 //
667 // The thread is still suspended when we reach here. Thread must be explicit started
668 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
669 // by calling Threads:add. The reason why this is not done here, is because the thread
670 // object must be fully initialized (take a look at JVM_Start)
671 }
672
673 JavaThread::~JavaThread() {
674
675 // Enqueue OopHandles for release by the service thread.
676 add_oop_handles_for_release();
677
678 // Return the sleep event to the free list
679 ParkEvent::Release(_SleepEvent);
680 _SleepEvent = nullptr;
681
682 // Free any remaining previous UnrollBlock
683 vframeArray* old_array = vframe_array_last();
684
685 if (old_array != nullptr) {
686 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
687 old_array->set_unroll_block(nullptr);
688 delete old_info;
689 delete old_array;
690 }
691
692 JvmtiDeferredUpdates* updates = deferred_updates();
693 if (updates != nullptr) {
694 // This can only happen if thread is destroyed before deoptimization occurs.
695 assert(updates->count() > 0, "Updates holder not deleted");
696 // free deferred updates.
697 delete updates;
698 set_deferred_updates(nullptr);
699 }
700
701 // All Java related clean up happens in exit
702 ThreadSafepointState::destroy(this);
703 if (_thread_stat != nullptr) delete _thread_stat;
704
705 #if INCLUDE_JVMCI
706 if (JVMCICounterSize > 0) {
707 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
708 }
709 #endif // INCLUDE_JVMCI
710 }
711
712
713 // First JavaThread specific code executed by a new Java thread.
714 void JavaThread::pre_run() {
715 // empty - see comments in run()
716 }
717
718 // The main routine called by a new Java thread. This isn't overridden
719 // by subclasses, instead different subclasses define a different "entry_point"
720 // which defines the actual logic for that kind of thread.
721 void JavaThread::run() {
722 // initialize thread-local alloc buffer related fields
723 initialize_tlab();
724
725 _stack_overflow_state.create_stack_guard_pages();
726
727 cache_global_variables();
728
729 // Thread is now sufficiently initialized to be handled by the safepoint code as being
730 // in the VM. Change thread state from _thread_new to _thread_in_vm
731 assert(this->thread_state() == _thread_new, "wrong thread state");
732 set_thread_state(_thread_in_vm);
733
734 // Before a thread is on the threads list it is always safe, so after leaving the
735 // _thread_new we should emit a instruction barrier. The distance to modified code
736 // from here is probably far enough, but this is consistent and safe.
737 OrderAccess::cross_modify_fence();
738
739 assert(JavaThread::current() == this, "sanity check");
740 assert(!Thread::current()->owns_locks(), "sanity check");
741
742 JFR_ONLY(Jfr::on_thread_start(this);)
743
744 DTRACE_THREAD_PROBE(start, this);
745
746 // This operation might block. We call that after all safepoint checks for a new thread has
747 // been completed.
748 set_active_handles(JNIHandleBlock::allocate_block());
749
750 if (JvmtiExport::should_post_thread_life()) {
751 JvmtiExport::post_thread_start(this);
752
753 }
754
755 if (AlwaysPreTouchStacks) {
756 pretouch_stack();
757 }
758
759 // We call another function to do the rest so we are sure that the stack addresses used
760 // from there will be lower than the stack base just computed.
761 thread_main_inner();
762 }
763
764 void JavaThread::thread_main_inner() {
765 assert(JavaThread::current() == this, "sanity check");
766 assert(_threadObj.peek() != nullptr || is_aot_thread(), "just checking");
767
768 // Execute thread entry point unless this thread has a pending exception.
769 // Note: Due to JVMTI StopThread we can have pending exceptions already!
770 if (!this->has_pending_exception()) {
771 {
772 ResourceMark rm(this);
773 this->set_native_thread_name(this->name());
774 }
775 HandleMark hm(this);
776 this->entry_point()(this, this);
777 }
778
779 DTRACE_THREAD_PROBE(stop, this);
780
781 // Cleanup is handled in post_run()
782 }
783
784 // Shared teardown for all JavaThreads
785 void JavaThread::post_run() {
786 this->exit(false);
787 this->unregister_thread_stack_with_NMT();
788 // Defer deletion to here to ensure 'this' is still referenceable in call_run
789 // for any shared tear-down.
790 this->smr_delete();
791 }
792
793 static void ensure_join(JavaThread* thread) {
794 // We do not need to grab the Threads_lock, since we are operating on ourself.
795 Handle threadObj(thread, thread->threadObj());
796 assert(threadObj.not_null(), "java thread object must exist");
797 ObjectLocker lock(threadObj, thread);
798 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
799 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
800 // Clear the native thread instance - this makes isAlive return false and allows the join()
801 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
802 // requirements.
803 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
804 java_lang_Thread::release_set_thread(threadObj(), nullptr);
805 lock.notify_all(thread);
806 // Ignore pending exception, since we are exiting anyway
807 thread->clear_pending_exception();
808 }
809
810 static bool is_daemon(oop threadObj) {
811 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
812 }
813
814 // For any new cleanup additions, please check to see if they need to be applied to
815 // cleanup_failed_attach_current_thread as well.
816 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
817 assert(this == JavaThread::current(), "thread consistency check");
818 assert(!is_exiting(), "should not be exiting or terminated already");
819
820 elapsedTimer _timer_exit_phase1;
821 elapsedTimer _timer_exit_phase2;
822 elapsedTimer _timer_exit_phase3;
823 elapsedTimer _timer_exit_phase4;
824
825 om_clear_monitor_cache();
826
827 if (log_is_enabled(Debug, os, thread, timer)) {
828 _timer_exit_phase1.start();
829 }
830
831 HandleMark hm(this);
832 Handle uncaught_exception(this, this->pending_exception());
833 this->clear_pending_exception();
834 Handle threadObj(this, this->threadObj());
835 assert(threadObj.not_null(), "Java thread object should be created");
836
837 if (!destroy_vm) {
838 if (uncaught_exception.not_null()) {
839 EXCEPTION_MARK;
840 // Call method Thread.dispatchUncaughtException().
841 Klass* thread_klass = vmClasses::Thread_klass();
842 JavaValue result(T_VOID);
843 JavaCalls::call_virtual(&result,
844 threadObj, thread_klass,
845 vmSymbols::dispatchUncaughtException_name(),
846 vmSymbols::throwable_void_signature(),
847 uncaught_exception,
848 THREAD);
849 if (HAS_PENDING_EXCEPTION) {
850 ResourceMark rm(this);
851 jio_fprintf(defaultStream::error_stream(),
852 "\nException: %s thrown from the UncaughtExceptionHandler"
853 " in thread \"%s\"\n",
854 pending_exception()->klass()->external_name(),
855 name());
856 CLEAR_PENDING_EXCEPTION;
857 }
858 }
859
860 if (!is_Compiler_thread()) {
861 // We have finished executing user-defined Java code and now have to do the
862 // implementation specific clean-up by calling Thread.exit(). We prevent any
863 // asynchronous exceptions from being delivered while in Thread.exit()
864 // to ensure the clean-up is not corrupted.
865 NoAsyncExceptionDeliveryMark _no_async(this);
866
867 EXCEPTION_MARK;
868 JavaValue result(T_VOID);
869 Klass* thread_klass = vmClasses::Thread_klass();
870 JavaCalls::call_virtual(&result,
871 threadObj, thread_klass,
872 vmSymbols::exit_method_name(),
873 vmSymbols::void_method_signature(),
874 THREAD);
875 CLEAR_PENDING_EXCEPTION;
876 }
877
878 // notify JVMTI
879 if (JvmtiExport::should_post_thread_life()) {
880 JvmtiExport::post_thread_end(this);
881 }
882 } else {
883 // before_exit() has already posted JVMTI THREAD_END events
884 }
885
886 // Cleanup any pending async exception now since we cannot access oops after
887 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
888 if (has_async_exception_condition()) {
889 handshake_state()->clean_async_exception_operation();
890 }
891
892 // The careful dance between thread suspension and exit is handled here.
893 // Since we are in thread_in_vm state and suspension is done with handshakes,
894 // we can just put in the exiting state and it will be correctly handled.
895 // Also, no more async exceptions will be added to the queue after this point.
896 set_terminated(_thread_exiting);
897 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
898
899 if (log_is_enabled(Debug, os, thread, timer)) {
900 _timer_exit_phase1.stop();
901 _timer_exit_phase2.start();
902 }
903
904 // Capture daemon status before the thread is marked as terminated.
905 bool daemon = is_daemon(threadObj());
906
907 // Notify waiters on thread object. This has to be done after exit() is called
908 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
909 // group should have the destroyed bit set before waiters are notified).
910 ensure_join(this);
911 assert(!this->has_pending_exception(), "ensure_join should have cleared");
912
913 if (log_is_enabled(Debug, os, thread, timer)) {
914 _timer_exit_phase2.stop();
915 _timer_exit_phase3.start();
916 }
917 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
918 // held by this thread must be released. The spec does not distinguish
919 // between JNI-acquired and regular Java monitors. We can only see
920 // regular Java monitors here if monitor enter-exit matching is broken.
921 //
922 // ensure_join() ignores IllegalThreadStateExceptions, and so does
923 // ObjectSynchronizer::release_monitors_owned_by_thread().
924 if (exit_type == jni_detach) {
925 // Sanity check even though JNI DetachCurrentThread() would have
926 // returned JNI_ERR if there was a Java frame. JavaThread exit
927 // should be done executing Java code by the time we get here.
928 assert(!this->has_last_Java_frame(),
929 "should not have a Java frame when detaching or exiting");
930 ObjectSynchronizer::release_monitors_owned_by_thread(this);
931 assert(!this->has_pending_exception(), "release_monitors should have cleared");
932 }
933
934 // These things needs to be done while we are still a Java Thread. Make sure that thread
935 // is in a consistent state, in case GC happens
936 JFR_ONLY(Jfr::on_thread_exit(this);)
937
938 if (active_handles() != nullptr) {
939 JNIHandleBlock* block = active_handles();
940 set_active_handles(nullptr);
941 JNIHandleBlock::release_block(block);
942 }
943
944 if (free_handle_block() != nullptr) {
945 JNIHandleBlock* block = free_handle_block();
946 set_free_handle_block(nullptr);
947 JNIHandleBlock::release_block(block);
948 }
949
950 // These have to be removed while this is still a valid thread.
951 _stack_overflow_state.remove_stack_guard_pages();
952
953 if (UseTLAB) {
954 retire_tlab();
955 }
956
957 if (JvmtiEnv::environments_might_exist()) {
958 JvmtiExport::cleanup_thread(this);
959 }
960
961 // We need to cache the thread name for logging purposes below as once
962 // we have called on_thread_detach this thread must not access any oops.
963 char* thread_name = nullptr;
964 if (log_is_enabled(Debug, os, thread, timer)) {
965 ResourceMark rm(this);
966 thread_name = os::strdup(name());
967 }
968
969 if (log_is_enabled(Info, os, thread)) {
970 ResourceMark rm(this);
971 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
972 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
973 name(), os::current_thread_id());
974 }
975
976 if (log_is_enabled(Debug, os, thread, timer)) {
977 _timer_exit_phase3.stop();
978 _timer_exit_phase4.start();
979 }
980
981 #if INCLUDE_JVMCI
982 if (JVMCICounterSize > 0) {
983 if (jvmci_counters_include(this)) {
984 for (int i = 0; i < JVMCICounterSize; i++) {
985 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
986 }
987 }
988 }
989 #endif // INCLUDE_JVMCI
990
991 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
992 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
993 Threads::remove(this, daemon);
994
995 if (log_is_enabled(Debug, os, thread, timer)) {
996 _timer_exit_phase4.stop();
997 log_debug(os, thread, timer)("name='%s'"
998 ", exit-phase1=" JLONG_FORMAT
999 ", exit-phase2=" JLONG_FORMAT
1000 ", exit-phase3=" JLONG_FORMAT
1001 ", exit-phase4=" JLONG_FORMAT,
1002 thread_name,
1003 _timer_exit_phase1.milliseconds(),
1004 _timer_exit_phase2.milliseconds(),
1005 _timer_exit_phase3.milliseconds(),
1006 _timer_exit_phase4.milliseconds());
1007 os::free(thread_name);
1008 }
1009 }
1010
1011 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1012 if (active_handles() != nullptr) {
1013 JNIHandleBlock* block = active_handles();
1014 set_active_handles(nullptr);
1015 JNIHandleBlock::release_block(block);
1016 }
1017
1018 if (free_handle_block() != nullptr) {
1019 JNIHandleBlock* block = free_handle_block();
1020 set_free_handle_block(nullptr);
1021 JNIHandleBlock::release_block(block);
1022 }
1023
1024 // These have to be removed while this is still a valid thread.
1025 _stack_overflow_state.remove_stack_guard_pages();
1026
1027 if (UseTLAB) {
1028 retire_tlab();
1029 }
1030
1031 Threads::remove(this, is_daemon);
1032 }
1033
1034 JavaThread* JavaThread::active() {
1035 Thread* thread = Thread::current();
1036 if (thread->is_Java_thread()) {
1037 return JavaThread::cast(thread);
1038 } else {
1039 assert(thread->is_VM_thread(), "this must be a vm thread");
1040 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1041 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1042 return ret;
1043 }
1044 }
1045
1046 oop JavaThread::exception_oop() const {
1047 return AtomicAccess::load(&_exception_oop);
1048 }
1049
1050 void JavaThread::set_exception_oop(oop o) {
1051 AtomicAccess::store(&_exception_oop, o);
1052 }
1053
1054 void JavaThread::handle_special_runtime_exit_condition() {
1055 // We mustn't block for object deopt if the thread is
1056 // currently executing in a JNI critical region, as that
1057 // can cause deadlock because allocation may be locked out
1058 // and the object deopt suspender may try to allocate.
1059 if (is_obj_deopt_suspend() && !in_critical()) {
1060 frame_anchor()->make_walkable();
1061 wait_for_object_deoptimization();
1062 }
1063 }
1064
1065
1066 // Asynchronous exceptions support
1067 //
1068 void JavaThread::handle_async_exception(oop java_throwable) {
1069 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1070 assert(!is_at_poll_safepoint(), "should have never called this method");
1071
1072 if (has_last_Java_frame()) {
1073 frame f = last_frame();
1074 if (f.is_runtime_frame()) {
1075 // If the topmost frame is a runtime stub, then we are calling into
1076 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1077 // must deoptimize the caller before continuing, as the compiled exception
1078 // handler table may not be valid.
1079 RegisterMap reg_map(this,
1080 RegisterMap::UpdateMap::skip,
1081 RegisterMap::ProcessFrames::include,
1082 RegisterMap::WalkContinuation::skip);
1083 frame compiled_frame = f.sender(®_map);
1084 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1085 Deoptimization::deoptimize(this, compiled_frame);
1086 }
1087 }
1088 }
1089
1090 // We cannot call Exceptions::_throw(...) here because we cannot block
1091 set_pending_exception(java_throwable, __FILE__, __LINE__);
1092
1093 clear_scopedValueBindings();
1094
1095 LogTarget(Info, exceptions) lt;
1096 if (lt.is_enabled()) {
1097 ResourceMark rm;
1098 LogStream ls(lt);
1099 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1100 if (has_last_Java_frame()) {
1101 frame f = last_frame();
1102 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1103 }
1104 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1105 }
1106 }
1107
1108 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1109 // Do not throw asynchronous exceptions against the compiler thread
1110 // or if the thread is already exiting.
1111 if (!can_call_java() || is_exiting()) {
1112 delete aehc;
1113 return;
1114 }
1115
1116 oop exception = aehc->exception();
1117 Handshake::execute(aehc, this); // Install asynchronous handshake
1118
1119 ResourceMark rm;
1120 if (log_is_enabled(Info, exceptions)) {
1121 log_info(exceptions)("Pending Async. exception installed of type: %s",
1122 exception->klass()->external_name());
1123 }
1124 // for AbortVMOnException flag
1125 Exceptions::debug_check_abort(exception->klass()->external_name());
1126
1127 oop vt_oop = vthread();
1128 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1129 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1130 this->interrupt();
1131 }
1132 }
1133
1134 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1135 AsyncExceptionHandshakeClosure* _aehc;
1136 public:
1137 InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1138 HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1139 ~InstallAsyncExceptionHandshakeClosure() {
1140 // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1141 delete _aehc;
1142 }
1143 void do_thread(Thread* thr) {
1144 JavaThread* target = JavaThread::cast(thr);
1145 target->install_async_exception(_aehc);
1146 _aehc = nullptr;
1147 }
1148 };
1149
1150 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1151 OopHandle e(Universe::vm_global(), java_throwable);
1152 InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1153 Handshake::execute(&iaeh, target);
1154 }
1155
1156 bool JavaThread::is_in_vthread_transition() const {
1157 DEBUG_ONLY(Thread* current = Thread::current();)
1158 assert(is_handshake_safe_for(current) || SafepointSynchronize::is_at_safepoint()
1159 || JavaThread::cast(current)->is_disabler_at_start(), "not safe");
1160 return AtomicAccess::load(&_is_in_vthread_transition);
1161 }
1162
1163 void JavaThread::set_is_in_vthread_transition(bool val) {
1164 assert(is_in_vthread_transition() != val, "already %s transition", val ? "inside" : "outside");
1165 AtomicAccess::store(&_is_in_vthread_transition, val);
1166 }
1167
1168 #ifdef ASSERT
1169 void JavaThread::set_is_vthread_transition_disabler(bool val) {
1170 _is_vthread_transition_disabler = val;
1171 }
1172
1173 void JavaThread::set_is_disabler_at_start(bool val) {
1174 _is_disabler_at_start = val;
1175 }
1176 #endif
1177
1178 // External suspension mechanism.
1179 //
1180 // Guarantees on return (for a valid target thread):
1181 // - Target thread will not execute any new bytecode.
1182 // - Target thread will not enter any new monitors.
1183 //
1184 bool JavaThread::java_suspend(bool register_vthread_SR) {
1185 // Suspending a vthread transition disabler can cause deadlocks.
1186 assert(!is_vthread_transition_disabler(), "no suspend allowed for vthread transition disablers");
1187
1188 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1189 "target JavaThread is not protected in calling context.");
1190 return this->suspend_resume_manager()->suspend(register_vthread_SR);
1191 }
1192
1193 bool JavaThread::java_resume(bool register_vthread_SR) {
1194 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1195 "missing ThreadsListHandle in calling context.");
1196 return this->suspend_resume_manager()->resume(register_vthread_SR);
1197 }
1198
1199 // Wait for another thread to perform object reallocation and relocking on behalf of
1200 // this thread. The current thread is required to change to _thread_blocked in order
1201 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1202 // handshake safe, the other thread can complete the handshake used to synchronize
1203 // with this thread and then perform the reallocation and relocking.
1204 // See EscapeBarrier::sync_and_suspend_*()
1205
1206 void JavaThread::wait_for_object_deoptimization() {
1207 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1208 assert(this == Thread::current(), "invariant");
1209
1210 bool spin_wait = os::is_MP();
1211 do {
1212 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1213 // Wait for object deoptimization if requested.
1214 if (spin_wait) {
1215 // A single deoptimization is typically very short. Microbenchmarks
1216 // showed 5% better performance when spinning.
1217 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1218 SpinYield spin(spin_limit);
1219 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1220 spin.wait();
1221 }
1222 // Spin just once
1223 spin_wait = false;
1224 } else {
1225 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1226 if (is_obj_deopt_suspend()) {
1227 ml.wait();
1228 }
1229 }
1230 // A handshake for obj. deoptimization suspend could have been processed so
1231 // we must check after processing.
1232 } while (is_obj_deopt_suspend());
1233 }
1234
1235 #ifdef ASSERT
1236 // Verify the JavaThread has not yet been published in the Threads::list, and
1237 // hence doesn't need protection from concurrent access at this stage.
1238 void JavaThread::verify_not_published() {
1239 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1240 // since an unpublished JavaThread doesn't participate in the
1241 // Thread-SMR protocol for keeping a ThreadsList alive.
1242 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1243 }
1244 #endif
1245
1246 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1247 // pending, when _suspend_flags is non-zero or when we need to process a stack
1248 // watermark. Also check for pending async exceptions (except unsafe access error).
1249 // Note only the native==>Java barriers can call this function when thread state
1250 // is _thread_in_native_trans.
1251 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1252 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1253 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1254
1255 thread->set_thread_state(_thread_in_vm);
1256
1257 // Enable WXWrite: called directly from interpreter native wrapper.
1258 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1259
1260 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1261
1262 // After returning from native, it could be that the stack frames are not
1263 // yet safe to use. We catch such situations in the subsequent stack watermark
1264 // barrier, which will trap unsafe stack frames.
1265 StackWatermarkSet::before_unwind(thread);
1266 }
1267
1268 #ifndef PRODUCT
1269 // Deoptimization
1270 // Function for testing deoptimization
1271 void JavaThread::deoptimize() {
1272 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1273 bool deopt = false; // Dump stack only if a deopt actually happens.
1274 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1275 // Iterate over all frames in the thread and deoptimize
1276 for (; !fst.is_done(); fst.next()) {
1277 if (fst.current()->can_be_deoptimized()) {
1278
1279 if (only_at) {
1280 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1281 // consists of comma or carriage return separated numbers so
1282 // search for the current bci in that string.
1283 address pc = fst.current()->pc();
1284 nmethod* nm = fst.current()->cb()->as_nmethod();
1285 ScopeDesc* sd = nm->scope_desc_at(pc);
1286 char buffer[8];
1287 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1288 size_t len = strlen(buffer);
1289 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1290 while (found != nullptr) {
1291 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1292 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1293 // Check that the bci found is bracketed by terminators.
1294 break;
1295 }
1296 found = strstr(found + 1, buffer);
1297 }
1298 if (!found) {
1299 continue;
1300 }
1301 }
1302
1303 if (DebugDeoptimization && !deopt) {
1304 deopt = true; // One-time only print before deopt
1305 tty->print_cr("[BEFORE Deoptimization]");
1306 trace_frames();
1307 trace_stack();
1308 }
1309 Deoptimization::deoptimize(this, *fst.current());
1310 }
1311 }
1312
1313 if (DebugDeoptimization && deopt) {
1314 tty->print_cr("[AFTER Deoptimization]");
1315 trace_frames();
1316 }
1317 }
1318
1319
1320 // Make zombies
1321 void JavaThread::make_zombies() {
1322 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1323 if (fst.current()->can_be_deoptimized()) {
1324 // it is a Java nmethod
1325 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1326 assert(nm != nullptr, "did not find nmethod");
1327 nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1328 }
1329 }
1330 }
1331 #endif // PRODUCT
1332
1333
1334 void JavaThread::deoptimize_marked_methods() {
1335 if (!has_last_Java_frame()) return;
1336 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1337 for (; !fst.is_done(); fst.next()) {
1338 if (fst.current()->should_be_deoptimized()) {
1339 Deoptimization::deoptimize(this, *fst.current());
1340 }
1341 }
1342 }
1343
1344 #ifdef ASSERT
1345 void JavaThread::verify_frame_info() {
1346 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1347 (has_last_Java_frame() && java_call_counter() > 0),
1348 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1349 has_last_Java_frame() ? "true" : "false", java_call_counter());
1350 }
1351 #endif
1352
1353 // Push on a new block of JNI handles.
1354 void JavaThread::push_jni_handle_block() {
1355 // Allocate a new block for JNI handles.
1356 // Inlined code from jni_PushLocalFrame()
1357 JNIHandleBlock* old_handles = active_handles();
1358 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1359 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1360 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1361 set_active_handles(new_handles);
1362 }
1363
1364 // Pop off the current block of JNI handles.
1365 void JavaThread::pop_jni_handle_block() {
1366 // Release our JNI handle block
1367 JNIHandleBlock* old_handles = active_handles();
1368 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1369 assert(new_handles != nullptr, "should never set active handles to null");
1370 set_active_handles(new_handles);
1371 old_handles->set_pop_frame_link(nullptr);
1372 JNIHandleBlock::release_block(old_handles, this);
1373 }
1374
1375 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1376 // Traverse the GCHandles
1377 Thread::oops_do_no_frames(f, cf);
1378
1379 if (active_handles() != nullptr) {
1380 active_handles()->oops_do(f);
1381 }
1382
1383 DEBUG_ONLY(verify_frame_info();)
1384
1385 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1386 // If we have deferred set_locals there might be oops waiting to be
1387 // written
1388 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1389 if (list != nullptr) {
1390 for (int i = 0; i < list->length(); i++) {
1391 list->at(i)->oops_do(f);
1392 }
1393 }
1394
1395 // Traverse instance variables at the end since the GC may be moving things
1396 // around using this function
1397 f->do_oop((oop*) &_vm_result_oop);
1398 f->do_oop((oop*) &_exception_oop);
1399 #if INCLUDE_JVMCI
1400 f->do_oop((oop*) &_jvmci_reserved_oop0);
1401
1402 if (_live_nmethod != nullptr && cf != nullptr) {
1403 cf->do_nmethod(_live_nmethod);
1404 }
1405 #endif
1406
1407 if (jvmti_thread_state() != nullptr) {
1408 jvmti_thread_state()->oops_do(f, cf);
1409 }
1410
1411 // The continuation oops are really on the stack. But there is typically at most
1412 // one of those per thread, so we handle them here in the oops_do_no_frames part
1413 // so that we don't have to sprinkle as many stack watermark checks where these
1414 // oops are used. We just need to make sure the thread has started processing.
1415 ContinuationEntry* entry = _cont_entry;
1416 while (entry != nullptr) {
1417 f->do_oop((oop*)entry->cont_addr());
1418 f->do_oop((oop*)entry->chunk_addr());
1419 entry = entry->parent();
1420 }
1421
1422 // Due to fast locking
1423 lock_stack().oops_do(f);
1424 }
1425
1426 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1427 if (!has_last_Java_frame()) {
1428 return;
1429 }
1430 // Finish any pending lazy GC activity for the frames
1431 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1432 // Traverse the execution stack
1433 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1434 fst.current()->oops_do(f, cf, fst.register_map());
1435 }
1436 }
1437
1438 #ifdef ASSERT
1439 void JavaThread::verify_states_for_handshake() {
1440 // This checks that the thread has a correct frame state during a handshake.
1441 verify_frame_info();
1442 }
1443 #endif
1444
1445 void JavaThread::nmethods_do(NMethodClosure* cf) {
1446 DEBUG_ONLY(verify_frame_info();)
1447 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1448
1449 if (has_last_Java_frame()) {
1450 // Traverse the execution stack
1451 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1452 fst.current()->nmethod_do(cf);
1453 }
1454 }
1455
1456 if (jvmti_thread_state() != nullptr) {
1457 jvmti_thread_state()->nmethods_do(cf);
1458 }
1459
1460 #if INCLUDE_JVMCI
1461 if (_live_nmethod != nullptr) {
1462 cf->do_nmethod(_live_nmethod);
1463 }
1464 #endif
1465 }
1466
1467 void JavaThread::metadata_do(MetadataClosure* f) {
1468 if (has_last_Java_frame()) {
1469 // Traverse the execution stack to call f() on the methods in the stack
1470 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1471 fst.current()->metadata_do(f);
1472 }
1473 } else if (is_Compiler_thread()) {
1474 // need to walk ciMetadata in current compile tasks to keep alive.
1475 CompilerThread* ct = (CompilerThread*)this;
1476 if (ct->env() != nullptr) {
1477 ct->env()->metadata_do(f);
1478 }
1479 CompileTask* task = ct->task();
1480 if (task != nullptr) {
1481 task->metadata_do(f);
1482 }
1483 }
1484 }
1485
1486 // Printing
1487 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1488 switch (_thread_state) {
1489 case _thread_uninitialized: return "_thread_uninitialized";
1490 case _thread_new: return "_thread_new";
1491 case _thread_new_trans: return "_thread_new_trans";
1492 case _thread_in_native: return "_thread_in_native";
1493 case _thread_in_native_trans: return "_thread_in_native_trans";
1494 case _thread_in_vm: return "_thread_in_vm";
1495 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1496 case _thread_in_Java: return "_thread_in_Java";
1497 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1498 case _thread_blocked: return "_thread_blocked";
1499 case _thread_blocked_trans: return "_thread_blocked_trans";
1500 default: return "unknown thread state";
1501 }
1502 }
1503
1504 void JavaThread::print_thread_state_on(outputStream *st) const {
1505 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1506 }
1507
1508 // Called by Threads::print() for VM_PrintThreads operation
1509 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1510 st->print_raw("\"");
1511 st->print_raw(name());
1512 st->print_raw("\" ");
1513 oop thread_oop = threadObj();
1514 if (thread_oop != nullptr) {
1515 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1516 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1517 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1518 }
1519 Thread::print_on(st, print_extended_info);
1520 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1521 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1522 if (thread_oop != nullptr) {
1523 if (is_vthread_mounted()) {
1524 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1525 } else {
1526 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1527 }
1528 }
1529 #ifndef PRODUCT
1530 _safepoint_state->print_on(st);
1531 #endif // PRODUCT
1532 if (is_Compiler_thread()) {
1533 CompileTask *task = ((CompilerThread*)this)->task();
1534 if (task != nullptr) {
1535 st->print(" Compiling: ");
1536 task->print(st, nullptr, true, false);
1537 } else {
1538 st->print(" No compile task");
1539 }
1540 st->cr();
1541 }
1542 }
1543
1544 void JavaThread::print() const { print_on(tty); }
1545
1546 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1547 st->print("%s", get_thread_name_string(buf, buflen));
1548 }
1549
1550 // Called by fatal error handler. The difference between this and
1551 // JavaThread::print() is that we can't grab lock or allocate memory.
1552 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1553 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1554 Thread* current = Thread::current_or_null_safe();
1555 assert(current != nullptr, "cannot be called by a detached thread");
1556 st->fill_to(60);
1557 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1558 // Only access threadObj() if current thread is not a JavaThread
1559 // or if it is a JavaThread that can safely access oops.
1560 oop thread_obj = threadObj();
1561 if (thread_obj != nullptr) {
1562 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1563 }
1564 }
1565 st->print(" [");
1566 st->print("%s", _get_thread_state_name(_thread_state));
1567 if (osthread()) {
1568 st->print(", id=%d", osthread()->thread_id());
1569 }
1570 // Use raw field members for stack base/size as this could be
1571 // called before a thread has run enough to initialize them.
1572 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1573 p2i(_stack_base - _stack_size), p2i(_stack_base),
1574 PROPERFMTARGS(_stack_size));
1575 st->print("]");
1576
1577 ThreadsSMRSupport::print_info_on(this, st);
1578 return;
1579 }
1580
1581
1582 // Verification
1583
1584 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1585 // ignore if there is no stack
1586 if (!has_last_Java_frame()) return;
1587 // traverse the stack frames. Starts from top frame.
1588 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1589 frame* fr = fst.current();
1590 f(fr, fst.register_map());
1591 }
1592 }
1593
1594 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1595
1596 void JavaThread::verify() {
1597 // Verify oops in the thread.
1598 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1599
1600 // Verify the stack frames.
1601 frames_do(frame_verify);
1602 }
1603
1604 // CR 6300358 (sub-CR 2137150)
1605 // Most callers of this method assume that it can't return null but a
1606 // thread may not have a name whilst it is in the process of attaching to
1607 // the VM - see CR 6412693, and there are places where a JavaThread can be
1608 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1609 // if vm exit occurs during initialization). These cases can all be accounted
1610 // for such that this method never returns null.
1611 const char* JavaThread::name() const {
1612 if (Thread::is_JavaThread_protected(/* target */ this)) {
1613 // The target JavaThread is protected so get_thread_name_string() is safe:
1614 return get_thread_name_string();
1615 }
1616
1617 // The target JavaThread is not protected so we return the default:
1618 return Thread::name();
1619 }
1620
1621 // Like name() but doesn't include the protection check. This must only be
1622 // called when it is known to be safe, even though the protection check can't tell
1623 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1624 const char* JavaThread::name_raw() const {
1625 return get_thread_name_string();
1626 }
1627
1628 // Returns a non-null representation of this thread's name, or a suitable
1629 // descriptive string if there is no set name.
1630 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1631 const char* name_str;
1632 #ifdef ASSERT
1633 Thread* current = Thread::current_or_null_safe();
1634 assert(current != nullptr, "cannot be called by a detached thread");
1635 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1636 // Only access threadObj() if current thread is not a JavaThread
1637 // or if it is a JavaThread that can safely access oops.
1638 #endif
1639 oop thread_obj = threadObj();
1640 if (thread_obj != nullptr) {
1641 oop name = java_lang_Thread::name(thread_obj);
1642 if (name != nullptr) {
1643 if (buf == nullptr) {
1644 name_str = java_lang_String::as_utf8_string(name);
1645 } else {
1646 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1647 }
1648 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1649 name_str = "<no-name - thread is attaching>";
1650 } else {
1651 name_str = "<un-named>";
1652 }
1653 } else {
1654 name_str = Thread::name();
1655 }
1656 #ifdef ASSERT
1657 } else {
1658 // Current JavaThread has exited...
1659 if (current == this) {
1660 // ... and is asking about itself:
1661 name_str = "<no-name - current JavaThread has exited>";
1662 } else {
1663 // ... and it can't safely determine this JavaThread's name so
1664 // use the default thread name.
1665 name_str = Thread::name();
1666 }
1667 }
1668 #endif
1669 assert(name_str != nullptr, "unexpected null thread name");
1670 return name_str;
1671 }
1672
1673 // Helper to extract the name from the thread oop for logging.
1674 const char* JavaThread::name_for(oop thread_obj) {
1675 assert(thread_obj != nullptr, "precondition");
1676 oop name = java_lang_Thread::name(thread_obj);
1677 const char* name_str;
1678 if (name != nullptr) {
1679 name_str = java_lang_String::as_utf8_string(name);
1680 } else {
1681 name_str = "<un-named>";
1682 }
1683 return name_str;
1684 }
1685
1686 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1687
1688 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1689 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1690 // Link Java Thread object <-> C++ Thread
1691
1692 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1693 // and put it into a new Handle. The Handle "thread_oop" can then
1694 // be used to pass the C++ thread object to other methods.
1695
1696 // Set the Java level thread object (jthread) field of the
1697 // new thread (a JavaThread *) to C++ thread object using the
1698 // "thread_oop" handle.
1699
1700 // Set the thread field (a JavaThread *) of the
1701 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1702
1703 Handle thread_oop(Thread::current(),
1704 JNIHandles::resolve_non_null(jni_thread));
1705 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1706 "must be initialized");
1707 set_threadOopHandles(thread_oop());
1708 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1709
1710 if (prio == NoPriority) {
1711 prio = java_lang_Thread::priority(thread_oop());
1712 assert(prio != NoPriority, "A valid priority should be present");
1713 }
1714
1715 // Push the Java priority down to the native thread; needs Threads_lock
1716 Thread::set_priority(this, prio);
1717
1718 // Add the new thread to the Threads list and set it in motion.
1719 // We must have threads lock in order to call Threads::add.
1720 // It is crucial that we do not block before the thread is
1721 // added to the Threads list for if a GC happens, then the java_thread oop
1722 // will not be visited by GC.
1723 Threads::add(this);
1724 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1725 // on a ThreadsList. We don't want to wait for the release when the
1726 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1727 // is already visible to JVM/TI via the ThreadsList.
1728 java_lang_Thread::release_set_thread(thread_oop(), this);
1729 }
1730
1731 oop JavaThread::current_park_blocker() {
1732 // Support for JSR-166 locks
1733 oop thread_oop = threadObj();
1734 if (thread_oop != nullptr) {
1735 return java_lang_Thread::park_blocker(thread_oop);
1736 }
1737 return nullptr;
1738 }
1739
1740 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1741 // This is the external format, selecting the platform or vthread
1742 // as applicable, and allowing for a native-only stack.
1743 void JavaThread::print_jni_stack() {
1744 assert(this == JavaThread::current(), "Can't print stack of other threads");
1745 if (!has_last_Java_frame()) {
1746 ResourceMark rm(this);
1747 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1748 if (buf == nullptr) {
1749 tty->print_cr("Unable to print native stack - out of memory");
1750 return;
1751 }
1752 NativeStackPrinter nsp(this);
1753 address lastpc = nullptr;
1754 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1755 true /*print_source_info */, -1 /* max stack */ );
1756 } else {
1757 print_active_stack_on(tty);
1758 }
1759 }
1760
1761 void JavaThread::print_stack_on(outputStream* st) {
1762 if (!has_last_Java_frame()) return;
1763
1764 Thread* current_thread = Thread::current();
1765 ResourceMark rm(current_thread);
1766 HandleMark hm(current_thread);
1767
1768 RegisterMap reg_map(this,
1769 RegisterMap::UpdateMap::include,
1770 RegisterMap::ProcessFrames::include,
1771 RegisterMap::WalkContinuation::skip);
1772 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1773 int count = 0;
1774 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1775 if (f->is_java_frame()) {
1776 javaVFrame* jvf = javaVFrame::cast(f);
1777 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1778
1779 // Print out lock information
1780 if (JavaMonitorsInStackTrace) {
1781 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1782 }
1783 } else {
1784 // Ignore non-Java frames
1785 }
1786
1787 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1788 count++;
1789 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1790 }
1791 }
1792
1793 void JavaThread::print_vthread_stack_on(outputStream* st) {
1794 assert(is_vthread_mounted(), "Caller should have checked this");
1795 assert(has_last_Java_frame(), "must be");
1796
1797 Thread* current_thread = Thread::current();
1798 ResourceMark rm(current_thread);
1799 HandleMark hm(current_thread);
1800
1801 RegisterMap reg_map(this,
1802 RegisterMap::UpdateMap::include,
1803 RegisterMap::ProcessFrames::include,
1804 RegisterMap::WalkContinuation::include);
1805 ContinuationEntry* cont_entry = last_continuation();
1806 vframe* start_vf = last_java_vframe(®_map);
1807 int count = 0;
1808 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1809 // Watch for end of vthread stack
1810 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1811 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1812 if (cont_entry->is_virtual_thread()) {
1813 break;
1814 }
1815 cont_entry = cont_entry->parent();
1816 }
1817 if (f->is_java_frame()) {
1818 javaVFrame* jvf = javaVFrame::cast(f);
1819 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1820
1821 // Print out lock information
1822 if (JavaMonitorsInStackTrace) {
1823 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1824 }
1825 } else {
1826 // Ignore non-Java frames
1827 }
1828
1829 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1830 count++;
1831 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1832 }
1833 }
1834
1835 void JavaThread::print_active_stack_on(outputStream* st) {
1836 if (is_vthread_mounted()) {
1837 print_vthread_stack_on(st);
1838 } else {
1839 print_stack_on(st);
1840 }
1841 }
1842
1843 #if INCLUDE_JVMTI
1844 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1845 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1846 set_jvmti_vthread(thread_oop);
1847
1848 // unbind current JvmtiThreadState from JavaThread
1849 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1850
1851 // bind new JvmtiThreadState to JavaThread
1852 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1853
1854 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1855 JvmtiThreadState::process_pending_interp_only(this);
1856
1857 return jvmti_thread_state();
1858 }
1859 #endif
1860
1861 // JVMTI PopFrame support
1862 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1863 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1864 if (in_bytes(size_in_bytes) != 0) {
1865 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1866 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1867 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1868 }
1869 }
1870
1871 void* JavaThread::popframe_preserved_args() {
1872 return _popframe_preserved_args;
1873 }
1874
1875 ByteSize JavaThread::popframe_preserved_args_size() {
1876 return in_ByteSize(_popframe_preserved_args_size);
1877 }
1878
1879 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1880 int sz = in_bytes(popframe_preserved_args_size());
1881 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1882 return in_WordSize(sz / wordSize);
1883 }
1884
1885 void JavaThread::popframe_free_preserved_args() {
1886 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1887 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1888 _popframe_preserved_args = nullptr;
1889 _popframe_preserved_args_size = 0;
1890 }
1891
1892 #ifndef PRODUCT
1893
1894 void JavaThread::trace_frames() {
1895 tty->print_cr("[Describe stack]");
1896 int frame_no = 1;
1897 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1898 tty->print(" %d. ", frame_no++);
1899 fst.current()->print_value_on(tty);
1900 tty->cr();
1901 }
1902 }
1903
1904 class PrintAndVerifyOopClosure: public OopClosure {
1905 protected:
1906 template <class T> inline void do_oop_work(T* p) {
1907 oop obj = RawAccess<>::oop_load(p);
1908 if (obj == nullptr) return;
1909 tty->print(INTPTR_FORMAT ": ", p2i(p));
1910 if (oopDesc::is_oop_or_null(obj)) {
1911 if (obj->is_objArray()) {
1912 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1913 } else {
1914 obj->print();
1915 }
1916 } else {
1917 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1918 }
1919 tty->cr();
1920 }
1921 public:
1922 virtual void do_oop(oop* p) { do_oop_work(p); }
1923 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1924 };
1925
1926 #ifdef ASSERT
1927 // Print or validate the layout of stack frames
1928 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1929 ResourceMark rm;
1930 PreserveExceptionMark pm(this);
1931 FrameValues values;
1932 int frame_no = 0;
1933 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1934 fst.current()->describe(values, ++frame_no, fst.register_map());
1935 if (depth == frame_no) break;
1936 }
1937 Continuation::describe(values);
1938 if (validate_only) {
1939 values.validate();
1940 } else {
1941 tty->print_cr("[Describe stack layout]");
1942 values.print(this);
1943 }
1944 }
1945 #endif
1946
1947 void JavaThread::trace_stack_from(vframe* start_vf) {
1948 ResourceMark rm;
1949 int vframe_no = 1;
1950 for (vframe* f = start_vf; f; f = f->sender()) {
1951 if (f->is_java_frame()) {
1952 javaVFrame::cast(f)->print_activation(vframe_no++);
1953 } else {
1954 f->print();
1955 }
1956 if (vframe_no > StackPrintLimit) {
1957 tty->print_cr("...<more frames>...");
1958 return;
1959 }
1960 }
1961 }
1962
1963
1964 void JavaThread::trace_stack() {
1965 if (!has_last_Java_frame()) return;
1966 Thread* current_thread = Thread::current();
1967 ResourceMark rm(current_thread);
1968 HandleMark hm(current_thread);
1969 RegisterMap reg_map(this,
1970 RegisterMap::UpdateMap::include,
1971 RegisterMap::ProcessFrames::include,
1972 RegisterMap::WalkContinuation::skip);
1973 trace_stack_from(last_java_vframe(®_map));
1974 }
1975
1976
1977 #endif // PRODUCT
1978
1979 frame JavaThread::vthread_last_frame() {
1980 assert (is_vthread_mounted(), "Virtual thread not mounted");
1981 return last_frame();
1982 }
1983
1984 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
1985 const ContinuationEntry* entry = vthread_continuation();
1986 guarantee (entry != nullptr, "Not a carrier thread");
1987 frame f = entry->to_frame();
1988 if (reg_map->process_frames()) {
1989 entry->flush_stack_processing(this);
1990 }
1991 entry->update_register_map(reg_map);
1992 return f.sender(reg_map);
1993 }
1994
1995 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
1996 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
1997 }
1998
1999 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2000 assert(reg_map != nullptr, "a map must be given");
2001 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2002 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2003 }
2004 return nullptr;
2005 }
2006
2007 Klass* JavaThread::security_get_caller_class(int depth) {
2008 ResetNoHandleMark rnhm;
2009 HandleMark hm(Thread::current());
2010
2011 vframeStream vfst(this);
2012 vfst.security_get_caller_frame(depth);
2013 if (!vfst.at_end()) {
2014 return vfst.method()->method_holder();
2015 }
2016 return nullptr;
2017 }
2018
2019 // Internal convenience function for millisecond resolution sleeps.
2020 bool JavaThread::sleep(jlong millis) {
2021 jlong nanos;
2022 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2023 // Conversion to nanos would overflow, saturate at max
2024 nanos = max_jlong;
2025 } else {
2026 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2027 }
2028 return sleep_nanos(nanos);
2029 }
2030
2031 // java.lang.Thread.sleep support
2032 // Returns true if sleep time elapsed as expected, and false
2033 // if the thread was interrupted or async exception was installed.
2034 bool JavaThread::sleep_nanos(jlong nanos) {
2035 assert(this == Thread::current(), "thread consistency check");
2036 assert(nanos >= 0, "nanos are in range");
2037
2038 ParkEvent * const slp = this->_SleepEvent;
2039 // Because there can be races with thread interruption sending an unpark()
2040 // to the event, we explicitly reset it here to avoid an immediate return.
2041 // The actual interrupt state will be checked before we park().
2042 slp->reset();
2043 // Thread interruption establishes a happens-before ordering in the
2044 // Java Memory Model, so we need to ensure we synchronize with the
2045 // interrupt state.
2046 OrderAccess::fence();
2047
2048 jlong prevtime = os::javaTimeNanos();
2049
2050 jlong nanos_remaining = nanos;
2051
2052 for (;;) {
2053 if (has_async_exception_condition()) {
2054 return false;
2055 }
2056 // interruption has precedence over timing out
2057 if (this->is_interrupted(true)) {
2058 return false;
2059 }
2060
2061 if (nanos_remaining <= 0) {
2062 return true;
2063 }
2064
2065 {
2066 ThreadBlockInVM tbivm(this);
2067 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2068 slp->park_nanos(nanos_remaining);
2069 }
2070
2071 // Update elapsed time tracking
2072 jlong newtime = os::javaTimeNanos();
2073 if (newtime - prevtime < 0) {
2074 // time moving backwards, should only happen if no monotonic clock
2075 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2076 assert(false,
2077 "unexpected time moving backwards detected in JavaThread::sleep()");
2078 } else {
2079 nanos_remaining -= (newtime - prevtime);
2080 }
2081 prevtime = newtime;
2082 }
2083 }
2084
2085 // Last thread running calls java.lang.Shutdown.shutdown()
2086 void JavaThread::invoke_shutdown_hooks() {
2087 HandleMark hm(this);
2088
2089 // We could get here with a pending exception, if so clear it now.
2090 if (this->has_pending_exception()) {
2091 this->clear_pending_exception();
2092 }
2093
2094 EXCEPTION_MARK;
2095 Klass* shutdown_klass =
2096 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2097 THREAD);
2098 if (shutdown_klass != nullptr) {
2099 // SystemDictionary::resolve_or_null will return null if there was
2100 // an exception. If we cannot load the Shutdown class, just don't
2101 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2102 // won't be run. Note that if a shutdown hook was registered,
2103 // the Shutdown class would have already been loaded
2104 // (Runtime.addShutdownHook will load it).
2105 JavaValue result(T_VOID);
2106 JavaCalls::call_static(&result,
2107 shutdown_klass,
2108 vmSymbols::shutdown_name(),
2109 vmSymbols::void_method_signature(),
2110 THREAD);
2111 }
2112 CLEAR_PENDING_EXCEPTION;
2113 }
2114
2115 #ifndef PRODUCT
2116 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2117 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2118 }
2119 #endif
2120
2121 // Helper function to create the java.lang.Thread object for a
2122 // VM-internal thread. The thread will have the given name, and be
2123 // a member of the "system" ThreadGroup.
2124 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2125 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2126
2127 // Initialize thread_oop to put it into the system threadGroup.
2128 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2129 Handle thread_group(THREAD, Universe::system_thread_group());
2130 Handle thread_oop =
2131 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2132 vmSymbols::threadgroup_string_void_signature(),
2133 thread_group,
2134 string,
2135 CHECK_NH);
2136
2137 return thread_oop;
2138 }
2139
2140 // Starts the target JavaThread as a daemon of the given priority, and
2141 // bound to the given java.lang.Thread instance.
2142 // The Threads_lock is held for the duration.
2143 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2144 Handle thread_oop, ThreadPriority prio) {
2145
2146 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2147
2148 MutexLocker mu(current, Threads_lock);
2149
2150 // Initialize the fields of the thread_oop first.
2151 if (prio != NoPriority) {
2152 java_lang_Thread::set_priority(thread_oop(), prio);
2153 // Note: we don't call os::set_priority here. Possibly we should,
2154 // else all threads should call it themselves when they first run.
2155 }
2156
2157 java_lang_Thread::set_daemon(thread_oop());
2158
2159 // Now bind the thread_oop to the target JavaThread.
2160 target->set_threadOopHandles(thread_oop());
2161 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2162
2163 Threads::add(target); // target is now visible for safepoint/handshake
2164 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2165 // on a ThreadsList. We don't want to wait for the release when the
2166 // Theads_lock is dropped when the 'mu' destructor is run since the
2167 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2168
2169 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2170 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2171 Thread::start(target);
2172 }
2173
2174 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2175 // At this point it may be possible that no osthread was created for the
2176 // JavaThread due to lack of resources. However, since this must work
2177 // for critical system threads just check and abort if this fails.
2178 if (thread->osthread() == nullptr) {
2179 // This isn't really an OOM condition, but historically this is what
2180 // we report.
2181 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2182 os::native_thread_creation_failed_msg());
2183 }
2184 }
2185
2186 void JavaThread::pretouch_stack() {
2187 // Given an established java thread stack with usable area followed by
2188 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2189 // from the current frame down to the start of the shadow zone.
2190 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2191 if (is_in_full_stack(end)) {
2192 char* p1 = (char*) alloca(1);
2193 address here = (address) &p1;
2194 if (is_in_full_stack(here) && here > end) {
2195 size_t to_alloc = here - end;
2196 char* p2 = (char*) alloca(to_alloc);
2197 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2198 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2199 os::pretouch_memory(p2, p2 + to_alloc,
2200 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2201 }
2202 }
2203 }
2204
2205 // Deferred OopHandle release support.
2206
2207 class OopHandleList : public CHeapObj<mtInternal> {
2208 static const int _count = 4;
2209 OopHandle _handles[_count];
2210 OopHandleList* _next;
2211 int _index;
2212 public:
2213 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2214 void add(OopHandle h) {
2215 assert(_index < _count, "too many additions");
2216 _handles[_index++] = h;
2217 }
2218 ~OopHandleList() {
2219 assert(_index == _count, "usage error");
2220 for (int i = 0; i < _index; i++) {
2221 _handles[i].release(JavaThread::thread_oop_storage());
2222 }
2223 }
2224 OopHandleList* next() const { return _next; }
2225 };
2226
2227 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2228
2229 // Called by the ServiceThread to do the work of releasing
2230 // the OopHandles.
2231 void JavaThread::release_oop_handles() {
2232 OopHandleList* list;
2233 {
2234 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2235 list = _oop_handle_list;
2236 _oop_handle_list = nullptr;
2237 }
2238 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2239
2240 while (list != nullptr) {
2241 OopHandleList* l = list;
2242 list = l->next();
2243 delete l;
2244 }
2245 }
2246
2247 // Add our OopHandles for later release.
2248 void JavaThread::add_oop_handles_for_release() {
2249 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2250 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2251 new_head->add(_threadObj);
2252 new_head->add(_vthread);
2253 new_head->add(_jvmti_vthread);
2254 new_head->add(_scopedValueCache);
2255 _oop_handle_list = new_head;
2256 Service_lock->notify_all();
2257 }
2258
2259 #if INCLUDE_JFR
2260 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2261 assert(result != freeze_ok, "sanity check");
2262 _last_freeze_fail_result = result;
2263 _last_freeze_fail_time = Ticks::now();
2264 }
2265
2266 // Post jdk.VirtualThreadPinned event
2267 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2268 assert(result != freeze_ok, "sanity check");
2269 if (event->should_commit()) {
2270 char reason[256];
2271 if (class_to_be_initialized() != nullptr) {
2272 ResourceMark rm(this);
2273 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2274 class_to_be_initialized()->external_name());
2275 event->set_pinnedReason(reason);
2276 } else if (class_being_initialized() != nullptr) {
2277 ResourceMark rm(this);
2278 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2279 class_being_initialized()->external_name());
2280 event->set_pinnedReason(reason);
2281 } else if (result == freeze_pinned_native) {
2282 event->set_pinnedReason("Native or VM frame on stack");
2283 } else {
2284 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2285 event->set_pinnedReason(reason);
2286 }
2287 event->set_blockingOperation(op);
2288 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2289 event->commit();
2290 }
2291 }
2292 #endif