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/inlineKlass.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oopHandle.inline.hpp"
55 #include "oops/verifyOopClosure.hpp"
56 #include "prims/jvm_misc.hpp"
57 #include "prims/jvmtiDeferredUpdates.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/continuation.hpp"
62 #include "runtime/continuationEntry.inline.hpp"
63 #include "runtime/continuationHelper.inline.hpp"
64 #include "runtime/deoptimization.hpp"
65 #include "runtime/frame.inline.hpp"
66 #include "runtime/handles.inline.hpp"
67 #include "runtime/handshake.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/javaCalls.hpp"
71 #include "runtime/javaThread.inline.hpp"
72 #include "runtime/jniHandles.inline.hpp"
73 #include "runtime/lockStack.inline.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.hpp"
76 #include "runtime/os.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/stackFrameStream.inline.hpp"
83 #include "runtime/stackWatermarkSet.hpp"
84 #include "runtime/synchronizer.hpp"
85 #include "runtime/threadIdentifier.hpp"
86 #include "runtime/threadSMR.inline.hpp"
87 #include "runtime/threadStatisticalInfo.hpp"
88 #include "runtime/threadWXSetters.inline.hpp"
89 #include "runtime/timer.hpp"
90 #include "runtime/timerTrace.hpp"
91 #include "runtime/vframe.inline.hpp"
92 #include "runtime/vframe_hp.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vmOperations.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "services/threadService.hpp"
97 #include "utilities/copy.hpp"
98 #include "utilities/defaultStream.hpp"
99 #include "utilities/dtrace.hpp"
100 #include "utilities/events.hpp"
101 #include "utilities/macros.hpp"
102 #include "utilities/nativeStackPrinter.hpp"
103 #include "utilities/preserveException.hpp"
104 #include "utilities/spinYield.hpp"
105 #include "utilities/vmError.hpp"
106 #if INCLUDE_JVMCI
107 #include "jvmci/jvmci.hpp"
108 #include "jvmci/jvmciEnv.hpp"
109 #endif
110 #if INCLUDE_JFR
111 #include "jfr/jfr.hpp"
112 #endif
113
114 // Set by os layer.
115 size_t JavaThread::_stack_size_at_create = 0;
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
122 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
123
124 #define DTRACE_THREAD_PROBE(probe, javathread) \
125 { \
126 ResourceMark rm(this); \
127 int len = 0; \
128 const char* name = (javathread)->name(); \
129 len = strlen(name); \
130 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
131 (char *) name, len, \
132 java_lang_Thread::thread_id((javathread)->threadObj()), \
133 (uintptr_t) (javathread)->osthread()->thread_id(), \
134 java_lang_Thread::is_daemon((javathread)->threadObj())); \
135 }
136
137 #else // ndef DTRACE_ENABLED
138
139 #define DTRACE_THREAD_PROBE(probe, javathread)
140
141 #endif // ndef DTRACE_ENABLED
142
143 void JavaThread::smr_delete() {
144 if (_on_thread_list) {
145 ThreadsSMRSupport::smr_delete(this);
146 } else {
147 delete this;
148 }
149 }
150
151 // Initialized by VMThread at vm_global_init
152 OopStorage* JavaThread::_thread_oop_storage = nullptr;
153
154 OopStorage* JavaThread::thread_oop_storage() {
155 assert(_thread_oop_storage != nullptr, "not yet initialized");
156 return _thread_oop_storage;
157 }
158
159 void JavaThread::set_threadOopHandles(oop p) {
160 assert(_thread_oop_storage != nullptr, "not yet initialized");
161 _threadObj = OopHandle(_thread_oop_storage, p);
162 _vthread = OopHandle(_thread_oop_storage, p);
163 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
164 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
165 }
166
167 oop JavaThread::threadObj() const {
168 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
169 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
170 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
171 // Instead callers must verify oop safe access.
172 return _threadObj.resolve();
173 }
174
175 oop JavaThread::vthread() const {
176 return _vthread.resolve();
177 }
178
179 void JavaThread::set_vthread(oop p) {
180 assert(_thread_oop_storage != nullptr, "not yet initialized");
181 _vthread.replace(p);
182 }
183
184 oop JavaThread::jvmti_vthread() const {
185 return _jvmti_vthread.resolve();
186 }
187
188 void JavaThread::set_jvmti_vthread(oop p) {
189 assert(_thread_oop_storage != nullptr, "not yet initialized");
190 _jvmti_vthread.replace(p);
191 }
192
193 // If there is a virtual thread mounted then return vthread() oop.
194 // Otherwise, return threadObj().
195 oop JavaThread::vthread_or_thread() const {
196 oop result = vthread();
197 if (result == nullptr) {
198 result = threadObj();
199 }
200 return result;
201 }
202
203 oop JavaThread::scopedValueCache() const {
204 return _scopedValueCache.resolve();
205 }
206
207 void JavaThread::set_scopedValueCache(oop p) {
208 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
209 _scopedValueCache.replace(p);
210 } else {
211 assert(p == nullptr, "not yet initialized");
212 }
213 }
214
215 void JavaThread::clear_scopedValueBindings() {
216 set_scopedValueCache(nullptr);
217 oop vthread_oop = vthread();
218 // vthread may be null here if we get a VM error during startup,
219 // before the java.lang.Thread instance has been created.
220 if (vthread_oop != nullptr) {
221 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
222 }
223 }
224
225 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
226 bool daemon, TRAPS) {
227 assert(thread_group.not_null(), "thread group should be specified");
228 assert(threadObj() == nullptr, "should only create Java thread object once");
229
230 InstanceKlass* ik = vmClasses::Thread_klass();
231 assert(ik->is_initialized(), "must be");
232 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
233
234 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
235 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
236 // constructor calls Thread.current(), which must be set here.
237 java_lang_Thread::set_thread(thread_oop(), this);
238 set_threadOopHandles(thread_oop());
239
240 JavaValue result(T_VOID);
241 if (thread_name != nullptr) {
242 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
243 // Thread gets assigned specified name and null target
244 JavaCalls::call_special(&result,
245 thread_oop,
246 ik,
247 vmSymbols::object_initializer_name(),
248 vmSymbols::threadgroup_string_void_signature(),
249 thread_group,
250 name,
251 CHECK);
252 } else {
253 // Thread gets assigned name "Thread-nnn" and null target
254 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
255 JavaCalls::call_special(&result,
256 thread_oop,
257 ik,
258 vmSymbols::object_initializer_name(),
259 vmSymbols::threadgroup_runnable_void_signature(),
260 thread_group,
261 Handle(),
262 CHECK);
263 }
264
265 os::set_priority(this, NormPriority);
266
267 if (daemon) {
268 java_lang_Thread::set_daemon(thread_oop());
269 }
270 }
271
272 // ======= JavaThread ========
273
274 #if INCLUDE_JVMCI
275
276 jlong* JavaThread::_jvmci_old_thread_counters;
277
278 static bool jvmci_counters_include(JavaThread* thread) {
279 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
280 }
281
282 void JavaThread::collect_counters(jlong* array, int length) {
283 assert(length == JVMCICounterSize, "wrong value");
284 for (int i = 0; i < length; i++) {
285 array[i] = _jvmci_old_thread_counters[i];
286 }
287 for (JavaThread* tp : ThreadsListHandle()) {
288 if (jvmci_counters_include(tp)) {
289 for (int i = 0; i < length; i++) {
290 array[i] += tp->_jvmci_counters[i];
291 }
292 }
293 }
294 }
295
296 // Attempt to enlarge the array for per thread counters.
297 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
298 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
299 if (new_counters == nullptr) {
300 return nullptr;
301 }
302 if (old_counters == nullptr) {
303 old_counters = new_counters;
304 memset(old_counters, 0, sizeof(jlong) * new_size);
305 } else {
306 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
307 new_counters[i] = old_counters[i];
308 }
309 if (new_size > current_size) {
310 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
311 }
312 FREE_C_HEAP_ARRAY(jlong, old_counters);
313 }
314 return new_counters;
315 }
316
317 // Attempt to enlarge the array for per thread counters.
318 bool JavaThread::resize_counters(int current_size, int new_size) {
319 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
320 if (new_counters == nullptr) {
321 return false;
322 } else {
323 _jvmci_counters = new_counters;
324 return true;
325 }
326 }
327
328 class VM_JVMCIResizeCounters : public VM_Operation {
329 private:
330 int _new_size;
331 bool _failed;
332
333 public:
334 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
335 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
336 bool allow_nested_vm_operations() const { return true; }
337 void doit() {
338 // Resize the old thread counters array
339 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
340 if (new_counters == nullptr) {
341 _failed = true;
342 return;
343 } else {
344 JavaThread::_jvmci_old_thread_counters = new_counters;
345 }
346
347 // Now resize each threads array
348 for (JavaThread* tp : ThreadsListHandle()) {
349 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
350 _failed = true;
351 break;
352 }
353 }
354 if (!_failed) {
355 JVMCICounterSize = _new_size;
356 }
357 }
358
359 bool failed() { return _failed; }
360 };
361
362 bool JavaThread::resize_all_jvmci_counters(int new_size) {
363 VM_JVMCIResizeCounters op(new_size);
364 VMThread::execute(&op);
365 return !op.failed();
366 }
367
368 #endif // INCLUDE_JVMCI
369
370 #ifdef ASSERT
371 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
372 void JavaThread::check_possible_safepoint() {
373 if (_no_safepoint_count > 0) {
374 print_owned_locks();
375 assert(false, "Possible safepoint reached by thread that does not allow it");
376 }
377 #ifdef CHECK_UNHANDLED_OOPS
378 // Clear unhandled oops in JavaThreads so we get a crash right away.
379 clear_unhandled_oops();
380 #endif // CHECK_UNHANDLED_OOPS
381
382 // Macos/aarch64 should be in the right state for safepoint (e.g.
383 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
384 // happens in practice, making such issues hard to find and reproduce.
385 #if defined(__APPLE__) && defined(AARCH64)
386 if (AssertWXAtThreadSync) {
387 assert_wx_state(WXWrite);
388 }
389 #endif
390 }
391
392 void JavaThread::check_for_valid_safepoint_state() {
393 // Don't complain if running a debugging command.
394 if (DebuggingContext::is_enabled()) return;
395
396 // Check NoSafepointVerifier, which is implied by locks taken that can be
397 // shared with the VM thread. This makes sure that no locks with allow_vm_block
398 // are held.
399 check_possible_safepoint();
400
401 if (thread_state() != _thread_in_vm) {
402 fatal("LEAF method calling lock?");
403 }
404
405 if (GCALotAtAllSafepoints) {
406 // We could enter a safepoint here and thus have a gc
407 InterfaceSupport::check_gc_alot();
408 }
409 }
410 #endif // ASSERT
411
412 // A JavaThread is a normal Java thread
413
414 JavaThread::JavaThread(MemTag mem_tag) :
415 Thread(mem_tag),
416 // Initialize fields
417 _on_thread_list(false),
418 DEBUG_ONLY(_java_call_counter(0) COMMA)
419 _entry_point(nullptr),
420 _deopt_mark(nullptr),
421 _deopt_nmethod(nullptr),
422 _vframe_array_head(nullptr),
423 _vframe_array_last(nullptr),
424 _jvmti_deferred_updates(nullptr),
425 _callee_target(nullptr),
426 _vm_result_oop(nullptr),
427 _vm_result_metadata(nullptr),
428
429 _current_pending_monitor(nullptr),
430 _current_pending_monitor_is_from_java(true),
431 _current_waiting_monitor(nullptr),
432 _active_handles(nullptr),
433 _free_handle_block(nullptr),
434 _monitor_owner_id(0),
435
436 _suspend_flags(0),
437
438 _thread_state(_thread_new),
439 _saved_exception_pc(nullptr),
440 #ifdef ASSERT
441 _no_safepoint_count(0),
442 _visited_for_critical_count(false),
443 #endif
444
445 _terminated(_not_terminated),
446 _in_deopt_handler(0),
447 _doing_unsafe_access(false),
448 _do_not_unlock_if_synchronized(false),
449 #if INCLUDE_JVMTI
450 _carrier_thread_suspended(false),
451 _is_in_VTMS_transition(false),
452 _is_disable_suspend(false),
453 _is_in_java_upcall(false),
454 _VTMS_transition_mark(false),
455 _on_monitor_waited_event(false),
456 _contended_entered_monitor(nullptr),
457 #ifdef ASSERT
458 _is_VTMS_transition_disabler(false),
459 #endif
460 #endif
461 _jni_attach_state(_not_attaching_via_jni),
462 _is_in_internal_oome_mark(false),
463 #if INCLUDE_JVMCI
464 _pending_deoptimization(-1),
465 _pending_monitorenter(false),
466 _pending_transfer_to_interpreter(false),
467 _pending_failed_speculation(0),
468 _jvmci{nullptr},
469 _libjvmci_runtime(nullptr),
470 _jvmci_counters(nullptr),
471 _jvmci_reserved0(0),
472 _jvmci_reserved1(0),
473 _jvmci_reserved_oop0(nullptr),
474 _live_nmethod(nullptr),
475 #endif // INCLUDE_JVMCI
476
477 _exception_oop(oop()),
478 _exception_pc(nullptr),
479 _exception_handler_pc(nullptr),
480 _is_method_handle_return(0),
481
482 _jni_active_critical(0),
483 _pending_jni_exception_check_fn(nullptr),
484 _depth_first_number(0),
485
486 // JVMTI PopFrame support
487 _popframe_condition(popframe_inactive),
488 _frames_to_pop_failed_realloc(0),
489
490 _cont_entry(nullptr),
491 _cont_fastpath(nullptr),
492 _cont_fastpath_thread_state(1),
493 _held_monitor_count(0),
494 _jni_monitor_count(0),
495 _unlocked_inflated_monitor(nullptr),
496
497 _preempt_alternate_return(nullptr),
498 _preemption_cancelled(false),
499 _pending_interrupted_exception(false),
500
501 _handshake(this),
502 _suspend_resume_manager(this, &_handshake._lock),
503
504 _popframe_preserved_args(nullptr),
505 _popframe_preserved_args_size(0),
506
507 _jvmti_thread_state(nullptr),
508 _interp_only_mode(0),
509 _should_post_on_exceptions_flag(JNI_FALSE),
510 _thread_stat(new ThreadStatistics()),
511
512 _parker(),
513
514 _class_to_be_initialized(nullptr),
515 _class_being_initialized(nullptr),
516
517 _SleepEvent(ParkEvent::Allocate(this)),
518
519 #if INCLUDE_JFR
520 _last_freeze_fail_result(freeze_ok),
521 #endif
522
523 _lock_stack(this),
524 _om_cache(this) {
525 set_jni_functions(jni_functions());
526
527 #if INCLUDE_JVMCI
528 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
529 if (JVMCICounterSize > 0) {
530 resize_counters(0, (int) JVMCICounterSize);
531 }
532 #endif // INCLUDE_JVMCI
533
534 // Setup safepoint state info for this thread
535 ThreadSafepointState::create(this);
536
537 SafepointMechanism::initialize_header(this);
538
539 set_requires_cross_modify_fence(false);
540
541 pd_initialize();
542 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
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, "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 // Check for monitor counts being out of sync.
933 assert(held_monitor_count() == jni_monitor_count(),
934 "held monitor count should be equal to jni: %zd != %zd",
935 held_monitor_count(), jni_monitor_count());
936 // All in-use monitors, including JNI-locked ones, should have been released above.
937 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
938 held_monitor_count());
939 } else {
940 // Check for monitor counts being out of sync.
941 assert(held_monitor_count() == jni_monitor_count(),
942 "held monitor count should be equal to jni: %zd != %zd",
943 held_monitor_count(), jni_monitor_count());
944 // It is possible that a terminating thread failed to unlock monitors it locked
945 // via JNI so we don't assert the count is zero.
946 }
947
948 if (CheckJNICalls && jni_monitor_count() > 0) {
949 // We would like a fatal here, but due to we never checked this before there
950 // is a lot of tests which breaks, even with an error log.
951 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
952 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
953 }
954
955 // These things needs to be done while we are still a Java Thread. Make sure that thread
956 // is in a consistent state, in case GC happens
957 JFR_ONLY(Jfr::on_thread_exit(this);)
958
959 if (active_handles() != nullptr) {
960 JNIHandleBlock* block = active_handles();
961 set_active_handles(nullptr);
962 JNIHandleBlock::release_block(block);
963 }
964
965 if (free_handle_block() != nullptr) {
966 JNIHandleBlock* block = free_handle_block();
967 set_free_handle_block(nullptr);
968 JNIHandleBlock::release_block(block);
969 }
970
971 // These have to be removed while this is still a valid thread.
972 _stack_overflow_state.remove_stack_guard_pages();
973
974 if (UseTLAB) {
975 retire_tlab();
976 }
977
978 if (JvmtiEnv::environments_might_exist()) {
979 JvmtiExport::cleanup_thread(this);
980 }
981
982 // We need to cache the thread name for logging purposes below as once
983 // we have called on_thread_detach this thread must not access any oops.
984 char* thread_name = nullptr;
985 if (log_is_enabled(Debug, os, thread, timer)) {
986 ResourceMark rm(this);
987 thread_name = os::strdup(name());
988 }
989
990 if (log_is_enabled(Info, os, thread)) {
991 ResourceMark rm(this);
992 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
993 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
994 name(), os::current_thread_id());
995 }
996
997 if (log_is_enabled(Debug, os, thread, timer)) {
998 _timer_exit_phase3.stop();
999 _timer_exit_phase4.start();
1000 }
1001
1002 #if INCLUDE_JVMCI
1003 if (JVMCICounterSize > 0) {
1004 if (jvmci_counters_include(this)) {
1005 for (int i = 0; i < JVMCICounterSize; i++) {
1006 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1007 }
1008 }
1009 }
1010 #endif // INCLUDE_JVMCI
1011
1012 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1013 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1014 Threads::remove(this, daemon);
1015
1016 if (log_is_enabled(Debug, os, thread, timer)) {
1017 _timer_exit_phase4.stop();
1018 log_debug(os, thread, timer)("name='%s'"
1019 ", exit-phase1=" JLONG_FORMAT
1020 ", exit-phase2=" JLONG_FORMAT
1021 ", exit-phase3=" JLONG_FORMAT
1022 ", exit-phase4=" JLONG_FORMAT,
1023 thread_name,
1024 _timer_exit_phase1.milliseconds(),
1025 _timer_exit_phase2.milliseconds(),
1026 _timer_exit_phase3.milliseconds(),
1027 _timer_exit_phase4.milliseconds());
1028 os::free(thread_name);
1029 }
1030 }
1031
1032 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1033 if (active_handles() != nullptr) {
1034 JNIHandleBlock* block = active_handles();
1035 set_active_handles(nullptr);
1036 JNIHandleBlock::release_block(block);
1037 }
1038
1039 if (free_handle_block() != nullptr) {
1040 JNIHandleBlock* block = free_handle_block();
1041 set_free_handle_block(nullptr);
1042 JNIHandleBlock::release_block(block);
1043 }
1044
1045 // These have to be removed while this is still a valid thread.
1046 _stack_overflow_state.remove_stack_guard_pages();
1047
1048 if (UseTLAB) {
1049 retire_tlab();
1050 }
1051
1052 Threads::remove(this, is_daemon);
1053 }
1054
1055 JavaThread* JavaThread::active() {
1056 Thread* thread = Thread::current();
1057 if (thread->is_Java_thread()) {
1058 return JavaThread::cast(thread);
1059 } else {
1060 assert(thread->is_VM_thread(), "this must be a vm thread");
1061 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1062 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1063 return ret;
1064 }
1065 }
1066
1067 bool JavaThread::is_lock_owned(address adr) const {
1068 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1069 return is_in_full_stack(adr);
1070 }
1071
1072 oop JavaThread::exception_oop() const {
1073 return Atomic::load(&_exception_oop);
1074 }
1075
1076 void JavaThread::set_exception_oop(oop o) {
1077 Atomic::store(&_exception_oop, o);
1078 }
1079
1080 void JavaThread::handle_special_runtime_exit_condition() {
1081 if (is_obj_deopt_suspend()) {
1082 frame_anchor()->make_walkable();
1083 wait_for_object_deoptimization();
1084 }
1085 }
1086
1087
1088 // Asynchronous exceptions support
1089 //
1090 void JavaThread::handle_async_exception(oop java_throwable) {
1091 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1092 assert(!is_at_poll_safepoint(), "should have never called this method");
1093
1094 if (has_last_Java_frame()) {
1095 frame f = last_frame();
1096 if (f.is_runtime_frame()) {
1097 // If the topmost frame is a runtime stub, then we are calling into
1098 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1099 // must deoptimize the caller before continuing, as the compiled exception
1100 // handler table may not be valid.
1101 RegisterMap reg_map(this,
1102 RegisterMap::UpdateMap::skip,
1103 RegisterMap::ProcessFrames::include,
1104 RegisterMap::WalkContinuation::skip);
1105 frame compiled_frame = f.sender(®_map);
1106 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1107 Deoptimization::deoptimize(this, compiled_frame);
1108 }
1109 }
1110 }
1111
1112 // We cannot call Exceptions::_throw(...) here because we cannot block
1113 set_pending_exception(java_throwable, __FILE__, __LINE__);
1114
1115 clear_scopedValueBindings();
1116
1117 LogTarget(Info, exceptions) lt;
1118 if (lt.is_enabled()) {
1119 ResourceMark rm;
1120 LogStream ls(lt);
1121 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1122 if (has_last_Java_frame()) {
1123 frame f = last_frame();
1124 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1125 }
1126 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1127 }
1128 }
1129
1130 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1131 // Do not throw asynchronous exceptions against the compiler thread
1132 // or if the thread is already exiting.
1133 if (!can_call_java() || is_exiting()) {
1134 delete aehc;
1135 return;
1136 }
1137
1138 oop exception = aehc->exception();
1139 Handshake::execute(aehc, this); // Install asynchronous handshake
1140
1141 ResourceMark rm;
1142 if (log_is_enabled(Info, exceptions)) {
1143 log_info(exceptions)("Pending Async. exception installed of type: %s",
1144 exception->klass()->external_name());
1145 }
1146 // for AbortVMOnException flag
1147 Exceptions::debug_check_abort(exception->klass()->external_name());
1148
1149 oop vt_oop = vthread();
1150 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1151 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1152 this->interrupt();
1153 }
1154 }
1155
1156 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1157 AsyncExceptionHandshakeClosure* _aehc;
1158 public:
1159 InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1160 HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1161 ~InstallAsyncExceptionHandshakeClosure() {
1162 // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1163 delete _aehc;
1164 }
1165 void do_thread(Thread* thr) {
1166 JavaThread* target = JavaThread::cast(thr);
1167 target->install_async_exception(_aehc);
1168 _aehc = nullptr;
1169 }
1170 };
1171
1172 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1173 OopHandle e(Universe::vm_global(), java_throwable);
1174 InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1175 Handshake::execute(&iaeh, target);
1176 }
1177
1178 #if INCLUDE_JVMTI
1179 void JavaThread::set_is_in_VTMS_transition(bool val) {
1180 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1181 _is_in_VTMS_transition = val;
1182 }
1183
1184 #ifdef ASSERT
1185 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1186 _is_VTMS_transition_disabler = val;
1187 }
1188 #endif
1189 #endif
1190
1191 // External suspension mechanism.
1192 //
1193 // Guarantees on return (for a valid target thread):
1194 // - Target thread will not execute any new bytecode.
1195 // - Target thread will not enter any new monitors.
1196 //
1197 bool JavaThread::java_suspend(bool register_vthread_SR) {
1198 #if INCLUDE_JVMTI
1199 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1200 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1201 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1202 #endif
1203
1204 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1205 "target JavaThread is not protected in calling context.");
1206 return this->suspend_resume_manager()->suspend(register_vthread_SR);
1207 }
1208
1209 bool JavaThread::java_resume(bool register_vthread_SR) {
1210 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1211 "missing ThreadsListHandle in calling context.");
1212 return this->suspend_resume_manager()->resume(register_vthread_SR);
1213 }
1214
1215 // Wait for another thread to perform object reallocation and relocking on behalf of
1216 // this thread. The current thread is required to change to _thread_blocked in order
1217 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1218 // handshake safe, the other thread can complete the handshake used to synchronize
1219 // with this thread and then perform the reallocation and relocking.
1220 // See EscapeBarrier::sync_and_suspend_*()
1221
1222 void JavaThread::wait_for_object_deoptimization() {
1223 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1224 assert(this == Thread::current(), "invariant");
1225
1226 bool spin_wait = os::is_MP();
1227 do {
1228 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1229 // Wait for object deoptimization if requested.
1230 if (spin_wait) {
1231 // A single deoptimization is typically very short. Microbenchmarks
1232 // showed 5% better performance when spinning.
1233 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1234 SpinYield spin(spin_limit);
1235 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1236 spin.wait();
1237 }
1238 // Spin just once
1239 spin_wait = false;
1240 } else {
1241 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1242 if (is_obj_deopt_suspend()) {
1243 ml.wait();
1244 }
1245 }
1246 // A handshake for obj. deoptimization suspend could have been processed so
1247 // we must check after processing.
1248 } while (is_obj_deopt_suspend());
1249 }
1250
1251 #ifdef ASSERT
1252 // Verify the JavaThread has not yet been published in the Threads::list, and
1253 // hence doesn't need protection from concurrent access at this stage.
1254 void JavaThread::verify_not_published() {
1255 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1256 // since an unpublished JavaThread doesn't participate in the
1257 // Thread-SMR protocol for keeping a ThreadsList alive.
1258 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1259 }
1260 #endif
1261
1262 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1263 // pending, when _suspend_flags is non-zero or when we need to process a stack
1264 // watermark. Also check for pending async exceptions (except unsafe access error).
1265 // Note only the native==>Java barriers can call this function when thread state
1266 // is _thread_in_native_trans.
1267 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1268 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1269 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1270
1271 thread->set_thread_state(_thread_in_vm);
1272
1273 // Enable WXWrite: called directly from interpreter native wrapper.
1274 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1275
1276 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1277
1278 // After returning from native, it could be that the stack frames are not
1279 // yet safe to use. We catch such situations in the subsequent stack watermark
1280 // barrier, which will trap unsafe stack frames.
1281 StackWatermarkSet::before_unwind(thread);
1282 }
1283
1284 #ifndef PRODUCT
1285 // Deoptimization
1286 // Function for testing deoptimization
1287 void JavaThread::deoptimize() {
1288 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1289 bool deopt = false; // Dump stack only if a deopt actually happens.
1290 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1291 // Iterate over all frames in the thread and deoptimize
1292 for (; !fst.is_done(); fst.next()) {
1293 if (fst.current()->can_be_deoptimized()) {
1294
1295 if (only_at) {
1296 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1297 // consists of comma or carriage return separated numbers so
1298 // search for the current bci in that string.
1299 address pc = fst.current()->pc();
1300 nmethod* nm = fst.current()->cb()->as_nmethod();
1301 ScopeDesc* sd = nm->scope_desc_at(pc);
1302 char buffer[8];
1303 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1304 size_t len = strlen(buffer);
1305 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1306 while (found != nullptr) {
1307 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1308 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1309 // Check that the bci found is bracketed by terminators.
1310 break;
1311 }
1312 found = strstr(found + 1, buffer);
1313 }
1314 if (!found) {
1315 continue;
1316 }
1317 }
1318
1319 if (DebugDeoptimization && !deopt) {
1320 deopt = true; // One-time only print before deopt
1321 tty->print_cr("[BEFORE Deoptimization]");
1322 trace_frames();
1323 trace_stack();
1324 }
1325 Deoptimization::deoptimize(this, *fst.current());
1326 }
1327 }
1328
1329 if (DebugDeoptimization && deopt) {
1330 tty->print_cr("[AFTER Deoptimization]");
1331 trace_frames();
1332 }
1333 }
1334
1335
1336 // Make zombies
1337 void JavaThread::make_zombies() {
1338 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1339 if (fst.current()->can_be_deoptimized()) {
1340 // it is a Java nmethod
1341 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1342 assert(nm != nullptr, "did not find nmethod");
1343 nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1344 }
1345 }
1346 }
1347 #endif // PRODUCT
1348
1349
1350 void JavaThread::deoptimize_marked_methods() {
1351 if (!has_last_Java_frame()) return;
1352 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1353 for (; !fst.is_done(); fst.next()) {
1354 if (fst.current()->should_be_deoptimized()) {
1355 Deoptimization::deoptimize(this, *fst.current());
1356 }
1357 }
1358 }
1359
1360 #ifdef ASSERT
1361 void JavaThread::verify_frame_info() {
1362 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1363 (has_last_Java_frame() && java_call_counter() > 0),
1364 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1365 has_last_Java_frame() ? "true" : "false", java_call_counter());
1366 }
1367 #endif
1368
1369 // Push on a new block of JNI handles.
1370 void JavaThread::push_jni_handle_block() {
1371 // Allocate a new block for JNI handles.
1372 // Inlined code from jni_PushLocalFrame()
1373 JNIHandleBlock* old_handles = active_handles();
1374 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1375 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1376 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1377 set_active_handles(new_handles);
1378 }
1379
1380 // Pop off the current block of JNI handles.
1381 void JavaThread::pop_jni_handle_block() {
1382 // Release our JNI handle block
1383 JNIHandleBlock* old_handles = active_handles();
1384 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1385 assert(new_handles != nullptr, "should never set active handles to null");
1386 set_active_handles(new_handles);
1387 old_handles->set_pop_frame_link(nullptr);
1388 JNIHandleBlock::release_block(old_handles, this);
1389 }
1390
1391 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1392 // Verify that the deferred card marks have been flushed.
1393 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1394
1395 // Traverse the GCHandles
1396 Thread::oops_do_no_frames(f, cf);
1397
1398 if (active_handles() != nullptr) {
1399 active_handles()->oops_do(f);
1400 }
1401
1402 DEBUG_ONLY(verify_frame_info();)
1403
1404 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1405 // If we have deferred set_locals there might be oops waiting to be
1406 // written
1407 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1408 if (list != nullptr) {
1409 for (int i = 0; i < list->length(); i++) {
1410 list->at(i)->oops_do(f);
1411 }
1412 }
1413
1414 // Traverse instance variables at the end since the GC may be moving things
1415 // around using this function
1416 f->do_oop((oop*) &_vm_result_oop);
1417 f->do_oop((oop*) &_exception_oop);
1418 #if INCLUDE_JVMCI
1419 f->do_oop((oop*) &_jvmci_reserved_oop0);
1420
1421 if (_live_nmethod != nullptr && cf != nullptr) {
1422 cf->do_nmethod(_live_nmethod);
1423 }
1424 #endif
1425
1426 if (jvmti_thread_state() != nullptr) {
1427 jvmti_thread_state()->oops_do(f, cf);
1428 }
1429
1430 // The continuation oops are really on the stack. But there is typically at most
1431 // one of those per thread, so we handle them here in the oops_do_no_frames part
1432 // so that we don't have to sprinkle as many stack watermark checks where these
1433 // oops are used. We just need to make sure the thread has started processing.
1434 ContinuationEntry* entry = _cont_entry;
1435 while (entry != nullptr) {
1436 f->do_oop((oop*)entry->cont_addr());
1437 f->do_oop((oop*)entry->chunk_addr());
1438 entry = entry->parent();
1439 }
1440
1441 if (LockingMode == LM_LIGHTWEIGHT) {
1442 lock_stack().oops_do(f);
1443 }
1444 }
1445
1446 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1447 if (!has_last_Java_frame()) {
1448 return;
1449 }
1450 // Finish any pending lazy GC activity for the frames
1451 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1452 // Traverse the execution stack
1453 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1454 fst.current()->oops_do(f, cf, fst.register_map());
1455 }
1456 }
1457
1458 #ifdef ASSERT
1459 void JavaThread::verify_states_for_handshake() {
1460 // This checks that the thread has a correct frame state during a handshake.
1461 verify_frame_info();
1462 }
1463 #endif
1464
1465 void JavaThread::nmethods_do(NMethodClosure* cf) {
1466 DEBUG_ONLY(verify_frame_info();)
1467 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1468
1469 if (has_last_Java_frame()) {
1470 // Traverse the execution stack
1471 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1472 fst.current()->nmethod_do(cf);
1473 }
1474 }
1475
1476 if (jvmti_thread_state() != nullptr) {
1477 jvmti_thread_state()->nmethods_do(cf);
1478 }
1479
1480 #if INCLUDE_JVMCI
1481 if (_live_nmethod != nullptr) {
1482 cf->do_nmethod(_live_nmethod);
1483 }
1484 #endif
1485 }
1486
1487 void JavaThread::metadata_do(MetadataClosure* f) {
1488 if (has_last_Java_frame()) {
1489 // Traverse the execution stack to call f() on the methods in the stack
1490 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1491 fst.current()->metadata_do(f);
1492 }
1493 } else if (is_Compiler_thread()) {
1494 // need to walk ciMetadata in current compile tasks to keep alive.
1495 CompilerThread* ct = (CompilerThread*)this;
1496 if (ct->env() != nullptr) {
1497 ct->env()->metadata_do(f);
1498 }
1499 CompileTask* task = ct->task();
1500 if (task != nullptr) {
1501 task->metadata_do(f);
1502 }
1503 }
1504 }
1505
1506 // Printing
1507 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1508 switch (_thread_state) {
1509 case _thread_uninitialized: return "_thread_uninitialized";
1510 case _thread_new: return "_thread_new";
1511 case _thread_new_trans: return "_thread_new_trans";
1512 case _thread_in_native: return "_thread_in_native";
1513 case _thread_in_native_trans: return "_thread_in_native_trans";
1514 case _thread_in_vm: return "_thread_in_vm";
1515 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1516 case _thread_in_Java: return "_thread_in_Java";
1517 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1518 case _thread_blocked: return "_thread_blocked";
1519 case _thread_blocked_trans: return "_thread_blocked_trans";
1520 default: return "unknown thread state";
1521 }
1522 }
1523
1524 void JavaThread::print_thread_state_on(outputStream *st) const {
1525 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1526 }
1527
1528 // Called by Threads::print() for VM_PrintThreads operation
1529 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1530 st->print_raw("\"");
1531 st->print_raw(name());
1532 st->print_raw("\" ");
1533 oop thread_oop = threadObj();
1534 if (thread_oop != nullptr) {
1535 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1536 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1537 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1538 }
1539 Thread::print_on(st, print_extended_info);
1540 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1541 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1542 if (thread_oop != nullptr) {
1543 if (is_vthread_mounted()) {
1544 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1545 } else {
1546 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1547 }
1548 }
1549 #ifndef PRODUCT
1550 _safepoint_state->print_on(st);
1551 #endif // PRODUCT
1552 if (is_Compiler_thread()) {
1553 CompileTask *task = ((CompilerThread*)this)->task();
1554 if (task != nullptr) {
1555 st->print(" Compiling: ");
1556 task->print(st, nullptr, true, false);
1557 } else {
1558 st->print(" No compile task");
1559 }
1560 st->cr();
1561 }
1562 }
1563
1564 void JavaThread::print() const { print_on(tty); }
1565
1566 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1567 st->print("%s", get_thread_name_string(buf, buflen));
1568 }
1569
1570 // Called by fatal error handler. The difference between this and
1571 // JavaThread::print() is that we can't grab lock or allocate memory.
1572 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1573 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1574 Thread* current = Thread::current_or_null_safe();
1575 assert(current != nullptr, "cannot be called by a detached thread");
1576 st->fill_to(60);
1577 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1578 // Only access threadObj() if current thread is not a JavaThread
1579 // or if it is a JavaThread that can safely access oops.
1580 oop thread_obj = threadObj();
1581 if (thread_obj != nullptr) {
1582 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1583 }
1584 }
1585 st->print(" [");
1586 st->print("%s", _get_thread_state_name(_thread_state));
1587 if (osthread()) {
1588 st->print(", id=%d", osthread()->thread_id());
1589 }
1590 // Use raw field members for stack base/size as this could be
1591 // called before a thread has run enough to initialize them.
1592 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1593 p2i(_stack_base - _stack_size), p2i(_stack_base),
1594 PROPERFMTARGS(_stack_size));
1595 st->print("]");
1596
1597 ThreadsSMRSupport::print_info_on(this, st);
1598 return;
1599 }
1600
1601
1602 // Verification
1603
1604 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1605 // ignore if there is no stack
1606 if (!has_last_Java_frame()) return;
1607 // traverse the stack frames. Starts from top frame.
1608 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1609 frame* fr = fst.current();
1610 f(fr, fst.register_map());
1611 }
1612 }
1613
1614 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1615
1616 void JavaThread::verify() {
1617 // Verify oops in the thread.
1618 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1619
1620 // Verify the stack frames.
1621 frames_do(frame_verify);
1622 }
1623
1624 // CR 6300358 (sub-CR 2137150)
1625 // Most callers of this method assume that it can't return null but a
1626 // thread may not have a name whilst it is in the process of attaching to
1627 // the VM - see CR 6412693, and there are places where a JavaThread can be
1628 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1629 // if vm exit occurs during initialization). These cases can all be accounted
1630 // for such that this method never returns null.
1631 const char* JavaThread::name() const {
1632 if (Thread::is_JavaThread_protected(/* target */ this)) {
1633 // The target JavaThread is protected so get_thread_name_string() is safe:
1634 return get_thread_name_string();
1635 }
1636
1637 // The target JavaThread is not protected so we return the default:
1638 return Thread::name();
1639 }
1640
1641 // Like name() but doesn't include the protection check. This must only be
1642 // called when it is known to be safe, even though the protection check can't tell
1643 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1644 const char* JavaThread::name_raw() const {
1645 return get_thread_name_string();
1646 }
1647
1648 // Returns a non-null representation of this thread's name, or a suitable
1649 // descriptive string if there is no set name.
1650 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1651 const char* name_str;
1652 #ifdef ASSERT
1653 Thread* current = Thread::current_or_null_safe();
1654 assert(current != nullptr, "cannot be called by a detached thread");
1655 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1656 // Only access threadObj() if current thread is not a JavaThread
1657 // or if it is a JavaThread that can safely access oops.
1658 #endif
1659 oop thread_obj = threadObj();
1660 if (thread_obj != nullptr) {
1661 oop name = java_lang_Thread::name(thread_obj);
1662 if (name != nullptr) {
1663 if (buf == nullptr) {
1664 name_str = java_lang_String::as_utf8_string(name);
1665 } else {
1666 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1667 }
1668 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1669 name_str = "<no-name - thread is attaching>";
1670 } else {
1671 name_str = "<un-named>";
1672 }
1673 } else {
1674 name_str = Thread::name();
1675 }
1676 #ifdef ASSERT
1677 } else {
1678 // Current JavaThread has exited...
1679 if (current == this) {
1680 // ... and is asking about itself:
1681 name_str = "<no-name - current JavaThread has exited>";
1682 } else {
1683 // ... and it can't safely determine this JavaThread's name so
1684 // use the default thread name.
1685 name_str = Thread::name();
1686 }
1687 }
1688 #endif
1689 assert(name_str != nullptr, "unexpected null thread name");
1690 return name_str;
1691 }
1692
1693 // Helper to extract the name from the thread oop for logging.
1694 const char* JavaThread::name_for(oop thread_obj) {
1695 assert(thread_obj != nullptr, "precondition");
1696 oop name = java_lang_Thread::name(thread_obj);
1697 const char* name_str;
1698 if (name != nullptr) {
1699 name_str = java_lang_String::as_utf8_string(name);
1700 } else {
1701 name_str = "<un-named>";
1702 }
1703 return name_str;
1704 }
1705
1706 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1707
1708 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1709 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1710 // Link Java Thread object <-> C++ Thread
1711
1712 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1713 // and put it into a new Handle. The Handle "thread_oop" can then
1714 // be used to pass the C++ thread object to other methods.
1715
1716 // Set the Java level thread object (jthread) field of the
1717 // new thread (a JavaThread *) to C++ thread object using the
1718 // "thread_oop" handle.
1719
1720 // Set the thread field (a JavaThread *) of the
1721 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1722
1723 Handle thread_oop(Thread::current(),
1724 JNIHandles::resolve_non_null(jni_thread));
1725 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1726 "must be initialized");
1727 set_threadOopHandles(thread_oop());
1728 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1729
1730 if (prio == NoPriority) {
1731 prio = java_lang_Thread::priority(thread_oop());
1732 assert(prio != NoPriority, "A valid priority should be present");
1733 }
1734
1735 // Push the Java priority down to the native thread; needs Threads_lock
1736 Thread::set_priority(this, prio);
1737
1738 // Add the new thread to the Threads list and set it in motion.
1739 // We must have threads lock in order to call Threads::add.
1740 // It is crucial that we do not block before the thread is
1741 // added to the Threads list for if a GC happens, then the java_thread oop
1742 // will not be visited by GC.
1743 Threads::add(this);
1744 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1745 // on a ThreadsList. We don't want to wait for the release when the
1746 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1747 // is already visible to JVM/TI via the ThreadsList.
1748 java_lang_Thread::release_set_thread(thread_oop(), this);
1749 }
1750
1751 oop JavaThread::current_park_blocker() {
1752 // Support for JSR-166 locks
1753 oop thread_oop = threadObj();
1754 if (thread_oop != nullptr) {
1755 return java_lang_Thread::park_blocker(thread_oop);
1756 }
1757 return nullptr;
1758 }
1759
1760 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1761 // This is the external format, selecting the platform or vthread
1762 // as applicable, and allowing for a native-only stack.
1763 void JavaThread::print_jni_stack() {
1764 assert(this == JavaThread::current(), "Can't print stack of other threads");
1765 if (!has_last_Java_frame()) {
1766 ResourceMark rm(this);
1767 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1768 if (buf == nullptr) {
1769 tty->print_cr("Unable to print native stack - out of memory");
1770 return;
1771 }
1772 NativeStackPrinter nsp(this);
1773 address lastpc = nullptr;
1774 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1775 true /*print_source_info */, -1 /* max stack */ );
1776 } else {
1777 print_active_stack_on(tty);
1778 }
1779 }
1780
1781 void JavaThread::print_stack_on(outputStream* st) {
1782 if (!has_last_Java_frame()) return;
1783
1784 Thread* current_thread = Thread::current();
1785 ResourceMark rm(current_thread);
1786 HandleMark hm(current_thread);
1787
1788 RegisterMap reg_map(this,
1789 RegisterMap::UpdateMap::include,
1790 RegisterMap::ProcessFrames::include,
1791 RegisterMap::WalkContinuation::skip);
1792 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1793 int count = 0;
1794 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1795 if (f->is_java_frame()) {
1796 javaVFrame* jvf = javaVFrame::cast(f);
1797 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1798
1799 // Print out lock information
1800 if (JavaMonitorsInStackTrace) {
1801 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1802 }
1803 } else {
1804 // Ignore non-Java frames
1805 }
1806
1807 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1808 count++;
1809 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1810 }
1811 }
1812
1813 void JavaThread::print_vthread_stack_on(outputStream* st) {
1814 assert(is_vthread_mounted(), "Caller should have checked this");
1815 assert(has_last_Java_frame(), "must be");
1816
1817 Thread* current_thread = Thread::current();
1818 ResourceMark rm(current_thread);
1819 HandleMark hm(current_thread);
1820
1821 RegisterMap reg_map(this,
1822 RegisterMap::UpdateMap::include,
1823 RegisterMap::ProcessFrames::include,
1824 RegisterMap::WalkContinuation::include);
1825 ContinuationEntry* cont_entry = last_continuation();
1826 vframe* start_vf = last_java_vframe(®_map);
1827 int count = 0;
1828 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1829 // Watch for end of vthread stack
1830 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1831 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1832 if (cont_entry->is_virtual_thread()) {
1833 break;
1834 }
1835 cont_entry = cont_entry->parent();
1836 }
1837 if (f->is_java_frame()) {
1838 javaVFrame* jvf = javaVFrame::cast(f);
1839 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1840
1841 // Print out lock information
1842 if (JavaMonitorsInStackTrace) {
1843 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1844 }
1845 } else {
1846 // Ignore non-Java frames
1847 }
1848
1849 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1850 count++;
1851 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1852 }
1853 }
1854
1855 void JavaThread::print_active_stack_on(outputStream* st) {
1856 if (is_vthread_mounted()) {
1857 print_vthread_stack_on(st);
1858 } else {
1859 print_stack_on(st);
1860 }
1861 }
1862
1863 #if INCLUDE_JVMTI
1864 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1865 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1866 set_jvmti_vthread(thread_oop);
1867
1868 // unbind current JvmtiThreadState from JavaThread
1869 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1870
1871 // bind new JvmtiThreadState to JavaThread
1872 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1873
1874 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1875 JvmtiThreadState::process_pending_interp_only(this);
1876
1877 return jvmti_thread_state();
1878 }
1879 #endif
1880
1881 // JVMTI PopFrame support
1882 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1883 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1884 if (in_bytes(size_in_bytes) != 0) {
1885 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1886 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1887 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1888 }
1889 }
1890
1891 void* JavaThread::popframe_preserved_args() {
1892 return _popframe_preserved_args;
1893 }
1894
1895 ByteSize JavaThread::popframe_preserved_args_size() {
1896 return in_ByteSize(_popframe_preserved_args_size);
1897 }
1898
1899 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1900 int sz = in_bytes(popframe_preserved_args_size());
1901 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1902 return in_WordSize(sz / wordSize);
1903 }
1904
1905 void JavaThread::popframe_free_preserved_args() {
1906 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1907 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1908 _popframe_preserved_args = nullptr;
1909 _popframe_preserved_args_size = 0;
1910 }
1911
1912 #ifndef PRODUCT
1913
1914 void JavaThread::trace_frames() {
1915 tty->print_cr("[Describe stack]");
1916 int frame_no = 1;
1917 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1918 tty->print(" %d. ", frame_no++);
1919 fst.current()->print_value_on(tty);
1920 tty->cr();
1921 }
1922 }
1923
1924 class PrintAndVerifyOopClosure: public OopClosure {
1925 protected:
1926 template <class T> inline void do_oop_work(T* p) {
1927 oop obj = RawAccess<>::oop_load(p);
1928 if (obj == nullptr) return;
1929 tty->print(INTPTR_FORMAT ": ", p2i(p));
1930 if (oopDesc::is_oop_or_null(obj)) {
1931 if (obj->is_objArray()) {
1932 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1933 } else {
1934 obj->print();
1935 }
1936 } else {
1937 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1938 }
1939 tty->cr();
1940 }
1941 public:
1942 virtual void do_oop(oop* p) { do_oop_work(p); }
1943 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1944 };
1945
1946 #ifdef ASSERT
1947 // Print or validate the layout of stack frames
1948 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1949 ResourceMark rm;
1950 PreserveExceptionMark pm(this);
1951 FrameValues values;
1952 int frame_no = 0;
1953 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1954 fst.current()->describe(values, ++frame_no, fst.register_map());
1955 if (depth == frame_no) break;
1956 }
1957 Continuation::describe(values);
1958 if (validate_only) {
1959 values.validate();
1960 } else {
1961 tty->print_cr("[Describe stack layout]");
1962 values.print(this);
1963 }
1964 }
1965 #endif
1966
1967 void JavaThread::trace_stack_from(vframe* start_vf) {
1968 ResourceMark rm;
1969 int vframe_no = 1;
1970 for (vframe* f = start_vf; f; f = f->sender()) {
1971 if (f->is_java_frame()) {
1972 javaVFrame::cast(f)->print_activation(vframe_no++);
1973 } else {
1974 f->print();
1975 }
1976 if (vframe_no > StackPrintLimit) {
1977 tty->print_cr("...<more frames>...");
1978 return;
1979 }
1980 }
1981 }
1982
1983
1984 void JavaThread::trace_stack() {
1985 if (!has_last_Java_frame()) return;
1986 Thread* current_thread = Thread::current();
1987 ResourceMark rm(current_thread);
1988 HandleMark hm(current_thread);
1989 RegisterMap reg_map(this,
1990 RegisterMap::UpdateMap::include,
1991 RegisterMap::ProcessFrames::include,
1992 RegisterMap::WalkContinuation::skip);
1993 trace_stack_from(last_java_vframe(®_map));
1994 }
1995
1996
1997 #endif // PRODUCT
1998
1999 // Slow-path increment of the held monitor counts. JNI locking is always
2000 // this slow-path.
2001 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2002 #ifdef SUPPORT_MONITOR_COUNT
2003
2004 if (LockingMode != LM_LEGACY) {
2005 // Nothing to do. Just do some sanity check.
2006 assert(_held_monitor_count == 0, "counter should not be used");
2007 assert(_jni_monitor_count == 0, "counter should not be used");
2008 return;
2009 }
2010
2011 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2012 _held_monitor_count += i;
2013 if (jni) {
2014 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2015 _jni_monitor_count += i;
2016 }
2017 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2018 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2019 #endif // SUPPORT_MONITOR_COUNT
2020 }
2021
2022 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2023 // this slow-path.
2024 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2025 #ifdef SUPPORT_MONITOR_COUNT
2026
2027 if (LockingMode != LM_LEGACY) {
2028 // Nothing to do. Just do some sanity check.
2029 assert(_held_monitor_count == 0, "counter should not be used");
2030 assert(_jni_monitor_count == 0, "counter should not be used");
2031 return;
2032 }
2033
2034 _held_monitor_count -= i;
2035 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2036 if (jni) {
2037 _jni_monitor_count -= i;
2038 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2039 }
2040 // When a thread is detaching with still owned JNI monitors, the logic that releases
2041 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2042 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2043 // JNI count is directly set to zero.
2044 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2045 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2046 #endif // SUPPORT_MONITOR_COUNT
2047 }
2048
2049 frame JavaThread::vthread_last_frame() {
2050 assert (is_vthread_mounted(), "Virtual thread not mounted");
2051 return last_frame();
2052 }
2053
2054 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2055 const ContinuationEntry* entry = vthread_continuation();
2056 guarantee (entry != nullptr, "Not a carrier thread");
2057 frame f = entry->to_frame();
2058 if (reg_map->process_frames()) {
2059 entry->flush_stack_processing(this);
2060 }
2061 entry->update_register_map(reg_map);
2062 return f.sender(reg_map);
2063 }
2064
2065 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2066 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2067 }
2068
2069 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2070 assert(reg_map != nullptr, "a map must be given");
2071 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2072 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2073 }
2074 return nullptr;
2075 }
2076
2077 Klass* JavaThread::security_get_caller_class(int depth) {
2078 ResetNoHandleMark rnhm;
2079 HandleMark hm(Thread::current());
2080
2081 vframeStream vfst(this);
2082 vfst.security_get_caller_frame(depth);
2083 if (!vfst.at_end()) {
2084 return vfst.method()->method_holder();
2085 }
2086 return nullptr;
2087 }
2088
2089 // Internal convenience function for millisecond resolution sleeps.
2090 bool JavaThread::sleep(jlong millis) {
2091 jlong nanos;
2092 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2093 // Conversion to nanos would overflow, saturate at max
2094 nanos = max_jlong;
2095 } else {
2096 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2097 }
2098 return sleep_nanos(nanos);
2099 }
2100
2101 // java.lang.Thread.sleep support
2102 // Returns true if sleep time elapsed as expected, and false
2103 // if the thread was interrupted or async exception was installed.
2104 bool JavaThread::sleep_nanos(jlong nanos) {
2105 assert(this == Thread::current(), "thread consistency check");
2106 assert(nanos >= 0, "nanos are in range");
2107
2108 ParkEvent * const slp = this->_SleepEvent;
2109 // Because there can be races with thread interruption sending an unpark()
2110 // to the event, we explicitly reset it here to avoid an immediate return.
2111 // The actual interrupt state will be checked before we park().
2112 slp->reset();
2113 // Thread interruption establishes a happens-before ordering in the
2114 // Java Memory Model, so we need to ensure we synchronize with the
2115 // interrupt state.
2116 OrderAccess::fence();
2117
2118 jlong prevtime = os::javaTimeNanos();
2119
2120 jlong nanos_remaining = nanos;
2121
2122 for (;;) {
2123 if (has_async_exception_condition()) {
2124 return false;
2125 }
2126 // interruption has precedence over timing out
2127 if (this->is_interrupted(true)) {
2128 return false;
2129 }
2130
2131 if (nanos_remaining <= 0) {
2132 return true;
2133 }
2134
2135 {
2136 ThreadBlockInVM tbivm(this);
2137 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2138 slp->park_nanos(nanos_remaining);
2139 }
2140
2141 // Update elapsed time tracking
2142 jlong newtime = os::javaTimeNanos();
2143 if (newtime - prevtime < 0) {
2144 // time moving backwards, should only happen if no monotonic clock
2145 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2146 assert(false,
2147 "unexpected time moving backwards detected in JavaThread::sleep()");
2148 } else {
2149 nanos_remaining -= (newtime - prevtime);
2150 }
2151 prevtime = newtime;
2152 }
2153 }
2154
2155 // Last thread running calls java.lang.Shutdown.shutdown()
2156 void JavaThread::invoke_shutdown_hooks() {
2157 HandleMark hm(this);
2158
2159 // We could get here with a pending exception, if so clear it now.
2160 if (this->has_pending_exception()) {
2161 this->clear_pending_exception();
2162 }
2163
2164 EXCEPTION_MARK;
2165 Klass* shutdown_klass =
2166 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2167 THREAD);
2168 if (shutdown_klass != nullptr) {
2169 // SystemDictionary::resolve_or_null will return null if there was
2170 // an exception. If we cannot load the Shutdown class, just don't
2171 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2172 // won't be run. Note that if a shutdown hook was registered,
2173 // the Shutdown class would have already been loaded
2174 // (Runtime.addShutdownHook will load it).
2175 JavaValue result(T_VOID);
2176 JavaCalls::call_static(&result,
2177 shutdown_klass,
2178 vmSymbols::shutdown_name(),
2179 vmSymbols::void_method_signature(),
2180 THREAD);
2181 }
2182 CLEAR_PENDING_EXCEPTION;
2183 }
2184
2185 #ifndef PRODUCT
2186 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2187 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2188 }
2189 #endif
2190
2191 // Helper function to create the java.lang.Thread object for a
2192 // VM-internal thread. The thread will have the given name, and be
2193 // a member of the "system" ThreadGroup.
2194 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2195 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2196
2197 // Initialize thread_oop to put it into the system threadGroup.
2198 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2199 Handle thread_group(THREAD, Universe::system_thread_group());
2200 Handle thread_oop =
2201 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2202 vmSymbols::threadgroup_string_void_signature(),
2203 thread_group,
2204 string,
2205 CHECK_NH);
2206
2207 return thread_oop;
2208 }
2209
2210 // Starts the target JavaThread as a daemon of the given priority, and
2211 // bound to the given java.lang.Thread instance.
2212 // The Threads_lock is held for the duration.
2213 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2214 Handle thread_oop, ThreadPriority prio) {
2215
2216 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2217
2218 MutexLocker mu(current, Threads_lock);
2219
2220 // Initialize the fields of the thread_oop first.
2221 if (prio != NoPriority) {
2222 java_lang_Thread::set_priority(thread_oop(), prio);
2223 // Note: we don't call os::set_priority here. Possibly we should,
2224 // else all threads should call it themselves when they first run.
2225 }
2226
2227 java_lang_Thread::set_daemon(thread_oop());
2228
2229 // Now bind the thread_oop to the target JavaThread.
2230 target->set_threadOopHandles(thread_oop());
2231 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2232
2233 Threads::add(target); // target is now visible for safepoint/handshake
2234 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2235 // on a ThreadsList. We don't want to wait for the release when the
2236 // Theads_lock is dropped when the 'mu' destructor is run since the
2237 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2238
2239 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2240 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2241 Thread::start(target);
2242 }
2243
2244 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2245 // At this point it may be possible that no osthread was created for the
2246 // JavaThread due to lack of resources. However, since this must work
2247 // for critical system threads just check and abort if this fails.
2248 if (thread->osthread() == nullptr) {
2249 // This isn't really an OOM condition, but historically this is what
2250 // we report.
2251 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2252 os::native_thread_creation_failed_msg());
2253 }
2254 }
2255
2256 void JavaThread::pretouch_stack() {
2257 // Given an established java thread stack with usable area followed by
2258 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2259 // from the current frame down to the start of the shadow zone.
2260 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2261 if (is_in_full_stack(end)) {
2262 char* p1 = (char*) alloca(1);
2263 address here = (address) &p1;
2264 if (is_in_full_stack(here) && here > end) {
2265 size_t to_alloc = here - end;
2266 char* p2 = (char*) alloca(to_alloc);
2267 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2268 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2269 os::pretouch_memory(p2, p2 + to_alloc,
2270 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2271 }
2272 }
2273 }
2274
2275 // Deferred OopHandle release support.
2276
2277 class OopHandleList : public CHeapObj<mtInternal> {
2278 static const int _count = 4;
2279 OopHandle _handles[_count];
2280 OopHandleList* _next;
2281 int _index;
2282 public:
2283 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2284 void add(OopHandle h) {
2285 assert(_index < _count, "too many additions");
2286 _handles[_index++] = h;
2287 }
2288 ~OopHandleList() {
2289 assert(_index == _count, "usage error");
2290 for (int i = 0; i < _index; i++) {
2291 _handles[i].release(JavaThread::thread_oop_storage());
2292 }
2293 }
2294 OopHandleList* next() const { return _next; }
2295 };
2296
2297 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2298
2299 // Called by the ServiceThread to do the work of releasing
2300 // the OopHandles.
2301 void JavaThread::release_oop_handles() {
2302 OopHandleList* list;
2303 {
2304 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2305 list = _oop_handle_list;
2306 _oop_handle_list = nullptr;
2307 }
2308 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2309
2310 while (list != nullptr) {
2311 OopHandleList* l = list;
2312 list = l->next();
2313 delete l;
2314 }
2315 }
2316
2317 // Add our OopHandles for later release.
2318 void JavaThread::add_oop_handles_for_release() {
2319 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2320 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2321 new_head->add(_threadObj);
2322 new_head->add(_vthread);
2323 new_head->add(_jvmti_vthread);
2324 new_head->add(_scopedValueCache);
2325 _oop_handle_list = new_head;
2326 Service_lock->notify_all();
2327 }
2328
2329 #if INCLUDE_JFR
2330 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2331 assert(result != freeze_ok, "sanity check");
2332 _last_freeze_fail_result = result;
2333 _last_freeze_fail_time = Ticks::now();
2334 }
2335
2336 // Post jdk.VirtualThreadPinned event
2337 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2338 assert(result != freeze_ok, "sanity check");
2339 if (event->should_commit()) {
2340 char reason[256];
2341 if (class_to_be_initialized() != nullptr) {
2342 ResourceMark rm(this);
2343 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2344 class_to_be_initialized()->external_name());
2345 event->set_pinnedReason(reason);
2346 } else if (class_being_initialized() != nullptr) {
2347 ResourceMark rm(this);
2348 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2349 class_being_initialized()->external_name());
2350 event->set_pinnedReason(reason);
2351 } else if (result == freeze_pinned_native) {
2352 event->set_pinnedReason("Native or VM frame on stack");
2353 } else {
2354 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2355 event->set_pinnedReason(reason);
2356 }
2357 event->set_blockingOperation(op);
2358 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2359 event->commit();
2360 }
2361 }
2362 #endif