1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "cds/dynamicArchive.hpp"
27 #include "ci/ciEnv.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/javaThreadStatus.hpp"
30 #include "classfile/systemDictionary.hpp"
31 #include "classfile/vmClasses.hpp"
32 #include "classfile/vmSymbols.hpp"
33 #include "code/codeCache.hpp"
34 #include "code/scopeDesc.hpp"
35 #include "compiler/compilerThread.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "gc/shared/oopStorage.hpp"
38 #include "gc/shared/oopStorageSet.hpp"
39 #include "gc/shared/tlab_globals.hpp"
40 #include "jfr/jfrEvents.hpp"
41 #include "jvm.h"
42 #include "jvmtifiles/jvmtiEnv.hpp"
43 #include "logging/log.hpp"
44 #include "logging/logAsyncWriter.hpp"
45 #include "logging/logStream.hpp"
46 #include "memory/allocation.inline.hpp"
47 #include "memory/iterator.hpp"
48 #include "memory/universe.hpp"
49 #include "oops/access.inline.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/klass.inline.hpp"
52 #include "oops/oop.inline.hpp"
53 #include "oops/oopHandle.inline.hpp"
54 #include "oops/verifyOopClosure.hpp"
55 #include "prims/jvm_misc.hpp"
56 #include "prims/jvmtiDeferredUpdates.hpp"
57 #include "prims/jvmtiExport.hpp"
58 #include "prims/jvmtiThreadState.inline.hpp"
59 #include "runtime/atomicAccess.hpp"
60 #include "runtime/continuation.hpp"
61 #include "runtime/continuationEntry.inline.hpp"
62 #include "runtime/continuationHelper.inline.hpp"
63 #include "runtime/deoptimization.hpp"
64 #include "runtime/frame.inline.hpp"
65 #include "runtime/handles.inline.hpp"
66 #include "runtime/handshake.hpp"
67 #include "runtime/interfaceSupport.inline.hpp"
68 #include "runtime/java.hpp"
69 #include "runtime/javaCalls.hpp"
70 #include "runtime/javaThread.inline.hpp"
71 #include "runtime/jniHandles.inline.hpp"
72 #include "runtime/lockStack.inline.hpp"
73 #include "runtime/mutexLocker.hpp"
74 #include "runtime/orderAccess.hpp"
75 #include "runtime/os.inline.hpp"
76 #include "runtime/osThread.hpp"
77 #include "runtime/safepoint.hpp"
78 #include "runtime/safepointMechanism.inline.hpp"
79 #include "runtime/safepointVerifiers.hpp"
80 #include "runtime/serviceThread.hpp"
81 #include "runtime/stackFrameStream.inline.hpp"
82 #include "runtime/stackWatermarkSet.hpp"
83 #include "runtime/synchronizer.hpp"
84 #include "runtime/threadIdentifier.hpp"
85 #include "runtime/threadSMR.inline.hpp"
86 #include "runtime/threadStatisticalInfo.hpp"
87 #include "runtime/threadWXSetters.inline.hpp"
88 #include "runtime/timer.hpp"
89 #include "runtime/timerTrace.hpp"
90 #include "runtime/vframe.inline.hpp"
91 #include "runtime/vframe_hp.hpp"
92 #include "runtime/vframeArray.hpp"
93 #include "runtime/vmOperations.hpp"
94 #include "runtime/vmThread.hpp"
95 #include "services/threadService.hpp"
96 #include "utilities/copy.hpp"
97 #include "utilities/defaultStream.hpp"
98 #include "utilities/dtrace.hpp"
99 #include "utilities/events.hpp"
100 #include "utilities/macros.hpp"
101 #include "utilities/nativeStackPrinter.hpp"
102 #include "utilities/preserveException.hpp"
103 #include "utilities/spinYield.hpp"
104 #include "utilities/vmError.hpp"
105 #if INCLUDE_JVMCI
106 #include "jvmci/jvmci.hpp"
107 #include "jvmci/jvmciEnv.hpp"
108 #endif
109 #if INCLUDE_JFR
110 #include "jfr/jfr.hpp"
111 #endif
112
113 // Set by os layer.
114 size_t JavaThread::_stack_size_at_create = 0;
115
116 #ifdef DTRACE_ENABLED
117
118 // Only bother with this argument setup if dtrace is available
119
120 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
121 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->name(); \
128 len = strlen(name); \
129 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
130 (char *) name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (uintptr_t) (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else // ndef DTRACE_ENABLED
137
138 #define DTRACE_THREAD_PROBE(probe, javathread)
139
140 #endif // ndef DTRACE_ENABLED
141
142 void JavaThread::smr_delete() {
143 if (_on_thread_list) {
144 ThreadsSMRSupport::smr_delete(this);
145 } else {
146 delete this;
147 }
148 }
149
150 // Initialized by VMThread at vm_global_init
151 OopStorage* JavaThread::_thread_oop_storage = nullptr;
152
153 OopStorage* JavaThread::thread_oop_storage() {
154 assert(_thread_oop_storage != nullptr, "not yet initialized");
155 return _thread_oop_storage;
156 }
157
158 void JavaThread::set_threadOopHandles(oop p) {
159 assert(_thread_oop_storage != nullptr, "not yet initialized");
160 _threadObj = OopHandle(_thread_oop_storage, p);
161 _vthread = OopHandle(_thread_oop_storage, p);
162 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
163 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
164 }
165
166 oop JavaThread::threadObj() const {
167 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
168 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
169 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
170 // Instead callers must verify oop safe access.
171 return _threadObj.resolve();
172 }
173
174 oop JavaThread::vthread() const {
175 return _vthread.resolve();
176 }
177
178 void JavaThread::set_vthread(oop p) {
179 assert(_thread_oop_storage != nullptr, "not yet initialized");
180 _vthread.replace(p);
181 }
182
183 oop JavaThread::jvmti_vthread() const {
184 return _jvmti_vthread.resolve();
185 }
186
187 void JavaThread::set_jvmti_vthread(oop p) {
188 assert(_thread_oop_storage != nullptr, "not yet initialized");
189 _jvmti_vthread.replace(p);
190 }
191
192 // If there is a virtual thread mounted then return vthread() oop.
193 // Otherwise, return threadObj().
194 oop JavaThread::vthread_or_thread() const {
195 oop result = vthread();
196 if (result == nullptr) {
197 result = threadObj();
198 }
199 return result;
200 }
201
202 oop JavaThread::scopedValueCache() const {
203 return _scopedValueCache.resolve();
204 }
205
206 void JavaThread::set_scopedValueCache(oop p) {
207 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
208 _scopedValueCache.replace(p);
209 } else {
210 assert(p == nullptr, "not yet initialized");
211 }
212 }
213
214 void JavaThread::clear_scopedValueBindings() {
215 set_scopedValueCache(nullptr);
216 oop vthread_oop = vthread();
217 // vthread may be null here if we get a VM error during startup,
218 // before the java.lang.Thread instance has been created.
219 if (vthread_oop != nullptr) {
220 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
221 }
222 }
223
224 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
225 bool daemon, TRAPS) {
226 assert(thread_group.not_null(), "thread group should be specified");
227 assert(threadObj() == nullptr, "should only create Java thread object once");
228
229 InstanceKlass* ik = vmClasses::Thread_klass();
230 assert(ik->is_initialized(), "must be");
231 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
232
233 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
234 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
235 // constructor calls Thread.current(), which must be set here.
236 java_lang_Thread::set_thread(thread_oop(), this);
237 set_threadOopHandles(thread_oop());
238
239 JavaValue result(T_VOID);
240 if (thread_name != nullptr) {
241 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
242 // Thread gets assigned specified name and null target
243 JavaCalls::call_special(&result,
244 thread_oop,
245 ik,
246 vmSymbols::object_initializer_name(),
247 vmSymbols::threadgroup_string_void_signature(),
248 thread_group,
249 name,
250 CHECK);
251 } else {
252 // Thread gets assigned name "Thread-nnn" and null target
253 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
254 JavaCalls::call_special(&result,
255 thread_oop,
256 ik,
257 vmSymbols::object_initializer_name(),
258 vmSymbols::threadgroup_runnable_void_signature(),
259 thread_group,
260 Handle(),
261 CHECK);
262 }
263
264 os::set_priority(this, NormPriority);
265
266 if (daemon) {
267 java_lang_Thread::set_daemon(thread_oop());
268 }
269 }
270
271 // ======= JavaThread ========
272
273 #if INCLUDE_JVMCI
274
275 jlong* JavaThread::_jvmci_old_thread_counters;
276
277 static bool jvmci_counters_include(JavaThread* thread) {
278 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
279 }
280
281 void JavaThread::collect_counters(jlong* array, int length) {
282 assert(length == JVMCICounterSize, "wrong value");
283 for (int i = 0; i < length; i++) {
284 array[i] = _jvmci_old_thread_counters[i];
285 }
286 for (JavaThread* tp : ThreadsListHandle()) {
287 if (jvmci_counters_include(tp)) {
288 for (int i = 0; i < length; i++) {
289 array[i] += tp->_jvmci_counters[i];
290 }
291 }
292 }
293 }
294
295 // Attempt to enlarge the array for per thread counters.
296 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
297 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
298 if (new_counters == nullptr) {
299 return nullptr;
300 }
301 if (old_counters == nullptr) {
302 old_counters = new_counters;
303 memset(old_counters, 0, sizeof(jlong) * new_size);
304 } else {
305 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
306 new_counters[i] = old_counters[i];
307 }
308 if (new_size > current_size) {
309 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
310 }
311 FREE_C_HEAP_ARRAY(jlong, old_counters);
312 }
313 return new_counters;
314 }
315
316 // Attempt to enlarge the array for per thread counters.
317 bool JavaThread::resize_counters(int current_size, int new_size) {
318 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
319 if (new_counters == nullptr) {
320 return false;
321 } else {
322 _jvmci_counters = new_counters;
323 return true;
324 }
325 }
326
327 class VM_JVMCIResizeCounters : public VM_Operation {
328 private:
329 int _new_size;
330 bool _failed;
331
332 public:
333 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
334 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
335 bool allow_nested_vm_operations() const { return true; }
336 void doit() {
337 // Resize the old thread counters array
338 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
339 if (new_counters == nullptr) {
340 _failed = true;
341 return;
342 } else {
343 JavaThread::_jvmci_old_thread_counters = new_counters;
344 }
345
346 // Now resize each threads array
347 for (JavaThread* tp : ThreadsListHandle()) {
348 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
349 _failed = true;
350 break;
351 }
352 }
353 if (!_failed) {
354 JVMCICounterSize = _new_size;
355 }
356 }
357
358 bool failed() { return _failed; }
359 };
360
361 bool JavaThread::resize_all_jvmci_counters(int new_size) {
362 VM_JVMCIResizeCounters op(new_size);
363 VMThread::execute(&op);
364 return !op.failed();
365 }
366
367 #endif // INCLUDE_JVMCI
368
369 #ifdef ASSERT
370 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
371 void JavaThread::check_possible_safepoint() {
372 if (_no_safepoint_count > 0) {
373 print_owned_locks();
374 assert(false, "Possible safepoint reached by thread that does not allow it");
375 }
376 #ifdef CHECK_UNHANDLED_OOPS
377 // Clear unhandled oops in JavaThreads so we get a crash right away.
378 clear_unhandled_oops();
379 #endif // CHECK_UNHANDLED_OOPS
380
381 // Macos/aarch64 should be in the right state for safepoint (e.g.
382 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
383 // happens in practice, making such issues hard to find and reproduce.
384 #if defined(__APPLE__) && defined(AARCH64)
385 if (AssertWXAtThreadSync) {
386 assert_wx_state(WXWrite);
387 }
388 #endif
389 }
390
391 void JavaThread::check_for_valid_safepoint_state() {
392 // Don't complain if running a debugging command.
393 if (DebuggingContext::is_enabled()) return;
394
395 // Check NoSafepointVerifier, which is implied by locks taken that can be
396 // shared with the VM thread. This makes sure that no locks with allow_vm_block
397 // are held.
398 check_possible_safepoint();
399
400 if (thread_state() != _thread_in_vm) {
401 fatal("LEAF method calling lock?");
402 }
403
404 if (GCALotAtAllSafepoints) {
405 // We could enter a safepoint here and thus have a gc
406 InterfaceSupport::check_gc_alot();
407 }
408 }
409 #endif // ASSERT
410
411 // A JavaThread is a normal Java thread
412
413 JavaThread::JavaThread(MemTag mem_tag) :
414 Thread(mem_tag),
415 // Initialize fields
416 _on_thread_list(false),
417 DEBUG_ONLY(_java_call_counter(0) COMMA)
418 _entry_point(nullptr),
419 _deopt_mark(nullptr),
420 _deopt_nmethod(nullptr),
421 _vframe_array_head(nullptr),
422 _vframe_array_last(nullptr),
423 _jvmti_deferred_updates(nullptr),
424 _callee_target(nullptr),
425 _vm_result_oop(nullptr),
426 _vm_result_metadata(nullptr),
427
428 _current_pending_monitor(nullptr),
429 _current_pending_monitor_is_from_java(true),
430 _current_waiting_monitor(nullptr),
431 _active_handles(nullptr),
432 _free_handle_block(nullptr),
433 _monitor_owner_id(0),
434
435 _suspend_flags(0),
436
437 _thread_state(_thread_new),
438 _saved_exception_pc(nullptr),
439 #ifdef ASSERT
440 _no_safepoint_count(0),
441 _visited_for_critical_count(false),
442 #endif
443
444 _terminated(_not_terminated),
445 _in_deopt_handler(0),
446 _doing_unsafe_access(false),
447 _do_not_unlock_if_synchronized(false),
448 #if INCLUDE_JVMTI
449 _carrier_thread_suspended(false),
450 _is_in_VTMS_transition(false),
451 _is_disable_suspend(false),
452 _is_in_java_upcall(false),
453 _VTMS_transition_mark(false),
454 _on_monitor_waited_event(false),
455 _contended_entered_monitor(nullptr),
456 #ifdef ASSERT
457 _is_VTMS_transition_disabler(false),
458 #endif
459 #endif
460 _jni_attach_state(_not_attaching_via_jni),
461 _is_in_internal_oome_mark(false),
462 #if INCLUDE_JVMCI
463 _pending_deoptimization(-1),
464 _pending_monitorenter(false),
465 _pending_transfer_to_interpreter(false),
466 _pending_failed_speculation(0),
467 _jvmci{nullptr},
468 _libjvmci_runtime(nullptr),
469 _jvmci_counters(nullptr),
470 _jvmci_reserved0(0),
471 _jvmci_reserved1(0),
472 _jvmci_reserved_oop0(nullptr),
473 _live_nmethod(nullptr),
474 #endif // INCLUDE_JVMCI
475
476 _exception_oop(oop()),
477 _exception_pc(nullptr),
478 _exception_handler_pc(nullptr),
479 _is_method_handle_return(0),
480
481 _jni_active_critical(0),
482 _pending_jni_exception_check_fn(nullptr),
483 _depth_first_number(0),
484
485 // JVMTI PopFrame support
486 _popframe_condition(popframe_inactive),
487 _frames_to_pop_failed_realloc(0),
488
489 _cont_entry(nullptr),
490 _cont_fastpath(nullptr),
491 _cont_fastpath_thread_state(1),
492 _held_monitor_count(0),
493 _jni_monitor_count(0),
494 _unlocked_inflated_monitor(nullptr),
495
496 _preempt_alternate_return(nullptr),
497 _preemption_cancelled(false),
498 _pending_interrupted_exception(false),
499
500 _handshake(this),
501 _suspend_resume_manager(this, &_handshake._lock),
502
503 _popframe_preserved_args(nullptr),
504 _popframe_preserved_args_size(0),
505
506 _jvmti_thread_state(nullptr),
507 _interp_only_mode(0),
508 _should_post_on_exceptions_flag(JNI_FALSE),
509 _thread_stat(new ThreadStatistics()),
510
511 _parker(),
512
513 _class_to_be_initialized(nullptr),
514 _class_being_initialized(nullptr),
515
516 _SleepEvent(ParkEvent::Allocate(this)),
517
518 #if INCLUDE_JFR
519 _last_freeze_fail_result(freeze_ok),
520 #endif
521
522 _lock_stack(this),
523 _om_cache(this) {
524 set_jni_functions(jni_functions());
525
526 #if INCLUDE_JVMCI
527 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
528 if (JVMCICounterSize > 0) {
529 resize_counters(0, (int) JVMCICounterSize);
530 }
531 #endif // INCLUDE_JVMCI
532
533 // Setup safepoint state info for this thread
534 ThreadSafepointState::create(this);
535
536 SafepointMechanism::initialize_header(this);
537
538 set_requires_cross_modify_fence(false);
539
540 pd_initialize();
541 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
542 }
543
544 JavaThread* JavaThread::create_attaching_thread() {
545 JavaThread* jt = new JavaThread();
546 jt->_jni_attach_state = _attaching_via_jni;
547 return jt;
548 }
549
550 // interrupt support
551
552 void JavaThread::interrupt() {
553 // All callers should have 'this' thread protected by a
554 // ThreadsListHandle so that it cannot terminate and deallocate
555 // itself.
556 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
557
558 // For Windows _interrupt_event
559 WINDOWS_ONLY(osthread()->set_interrupted(true);)
560
561 // For Thread.sleep
562 _SleepEvent->unpark();
563
564 // For JSR166 LockSupport.park
565 parker()->unpark();
566
567 // For ObjectMonitor and JvmtiRawMonitor
568 _ParkEvent->unpark();
569 }
570
571 bool JavaThread::is_interrupted(bool clear_interrupted) {
572 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
573
574 if (_threadObj.peek() == nullptr) {
575 // If there is no j.l.Thread then it is impossible to have
576 // been interrupted. We can find null during VM initialization
577 // or when a JNI thread is still in the process of attaching.
578 // In such cases this must be the current thread.
579 assert(this == Thread::current(), "invariant");
580 return false;
581 }
582
583 bool interrupted = java_lang_Thread::interrupted(threadObj());
584
585 // NOTE that since there is no "lock" around the interrupt and
586 // is_interrupted operations, there is the possibility that the
587 // interrupted flag will be "false" but that the
588 // low-level events will be in the signaled state. This is
589 // intentional. The effect of this is that Object.wait() and
590 // LockSupport.park() will appear to have a spurious wakeup, which
591 // is allowed and not harmful, and the possibility is so rare that
592 // it is not worth the added complexity to add yet another lock.
593 // For the sleep event an explicit reset is performed on entry
594 // to JavaThread::sleep, so there is no early return. It has also been
595 // recommended not to put the interrupted flag into the "event"
596 // structure because it hides the issue.
597 // Also, because there is no lock, we must only clear the interrupt
598 // state if we are going to report that we were interrupted; otherwise
599 // an interrupt that happens just after we read the field would be lost.
600 if (interrupted && clear_interrupted) {
601 assert(this == Thread::current(), "only the current thread can clear");
602 java_lang_Thread::set_interrupted(threadObj(), false);
603 WINDOWS_ONLY(osthread()->set_interrupted(false);)
604 }
605 return interrupted;
606 }
607
608 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
609 // the Java code in Object::wait which are not present in RawMonitorWait.
610 bool JavaThread::get_and_clear_interrupted() {
611 if (!is_interrupted(false)) {
612 return false;
613 }
614 oop thread_oop = vthread_or_thread();
615 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
616
617 if (!is_virtual) {
618 return is_interrupted(true);
619 }
620 // Virtual thread: clear interrupt status for both virtual and
621 // carrier threads under the interruptLock protection.
622 JavaThread* current = JavaThread::current();
623 HandleMark hm(current);
624 Handle thread_h(current, thread_oop);
625 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
626
627 // re-check the interrupt status under the interruptLock protection
628 bool interrupted = java_lang_Thread::interrupted(thread_h());
629
630 if (interrupted) {
631 assert(this == Thread::current(), "only the current thread can clear");
632 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
633 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
634 WINDOWS_ONLY(osthread()->set_interrupted(false);)
635 }
636 return interrupted;
637 }
638
639 void JavaThread::block_if_vm_exited() {
640 if (_terminated == _vm_exited) {
641 // _vm_exited is set at safepoint, and Threads_lock is never released
642 // so we will block here forever.
643 // Here we can be doing a jump from a safe state to an unsafe state without
644 // proper transition, but it happens after the final safepoint has begun so
645 // this jump won't cause any safepoint problems.
646 set_thread_state(_thread_in_vm);
647 Threads_lock->lock();
648 ShouldNotReachHere();
649 }
650 }
651
652 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
653 set_entry_point(entry_point);
654 // Create the native thread itself.
655 // %note runtime_23
656 os::ThreadType thr_type = os::java_thread;
657 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
658 os::java_thread;
659 os::create_thread(this, thr_type, stack_sz);
660 // The _osthread may be null here because we ran out of memory (too many threads active).
661 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
662 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
663 // the exception consists of creating the exception object & initializing it, initialization
664 // will leave the VM via a JavaCall and then all locks must be unlocked).
665 //
666 // The thread is still suspended when we reach here. Thread must be explicit started
667 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
668 // by calling Threads:add. The reason why this is not done here, is because the thread
669 // object must be fully initialized (take a look at JVM_Start)
670 }
671
672 JavaThread::~JavaThread() {
673
674 // Enqueue OopHandles for release by the service thread.
675 add_oop_handles_for_release();
676
677 // Return the sleep event to the free list
678 ParkEvent::Release(_SleepEvent);
679 _SleepEvent = nullptr;
680
681 // Free any remaining previous UnrollBlock
682 vframeArray* old_array = vframe_array_last();
683
684 if (old_array != nullptr) {
685 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
686 old_array->set_unroll_block(nullptr);
687 delete old_info;
688 delete old_array;
689 }
690
691 JvmtiDeferredUpdates* updates = deferred_updates();
692 if (updates != nullptr) {
693 // This can only happen if thread is destroyed before deoptimization occurs.
694 assert(updates->count() > 0, "Updates holder not deleted");
695 // free deferred updates.
696 delete updates;
697 set_deferred_updates(nullptr);
698 }
699
700 // All Java related clean up happens in exit
701 ThreadSafepointState::destroy(this);
702 if (_thread_stat != nullptr) delete _thread_stat;
703
704 #if INCLUDE_JVMCI
705 if (JVMCICounterSize > 0) {
706 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
707 }
708 #endif // INCLUDE_JVMCI
709 }
710
711
712 // First JavaThread specific code executed by a new Java thread.
713 void JavaThread::pre_run() {
714 // empty - see comments in run()
715 }
716
717 // The main routine called by a new Java thread. This isn't overridden
718 // by subclasses, instead different subclasses define a different "entry_point"
719 // which defines the actual logic for that kind of thread.
720 void JavaThread::run() {
721 // initialize thread-local alloc buffer related fields
722 initialize_tlab();
723
724 _stack_overflow_state.create_stack_guard_pages();
725
726 cache_global_variables();
727
728 // Thread is now sufficiently initialized to be handled by the safepoint code as being
729 // in the VM. Change thread state from _thread_new to _thread_in_vm
730 assert(this->thread_state() == _thread_new, "wrong thread state");
731 set_thread_state(_thread_in_vm);
732
733 // Before a thread is on the threads list it is always safe, so after leaving the
734 // _thread_new we should emit a instruction barrier. The distance to modified code
735 // from here is probably far enough, but this is consistent and safe.
736 OrderAccess::cross_modify_fence();
737
738 assert(JavaThread::current() == this, "sanity check");
739 assert(!Thread::current()->owns_locks(), "sanity check");
740
741 JFR_ONLY(Jfr::on_thread_start(this);)
742
743 DTRACE_THREAD_PROBE(start, this);
744
745 // This operation might block. We call that after all safepoint checks for a new thread has
746 // been completed.
747 set_active_handles(JNIHandleBlock::allocate_block());
748
749 if (JvmtiExport::should_post_thread_life()) {
750 JvmtiExport::post_thread_start(this);
751
752 }
753
754 if (AlwaysPreTouchStacks) {
755 pretouch_stack();
756 }
757
758 // We call another function to do the rest so we are sure that the stack addresses used
759 // from there will be lower than the stack base just computed.
760 thread_main_inner();
761 }
762
763 void JavaThread::thread_main_inner() {
764 assert(JavaThread::current() == this, "sanity check");
765 assert(_threadObj.peek() != nullptr, "just checking");
766
767 // Execute thread entry point unless this thread has a pending exception.
768 // Note: Due to JVMTI StopThread we can have pending exceptions already!
769 if (!this->has_pending_exception()) {
770 {
771 ResourceMark rm(this);
772 this->set_native_thread_name(this->name());
773 }
774 HandleMark hm(this);
775 this->entry_point()(this, this);
776 }
777
778 DTRACE_THREAD_PROBE(stop, this);
779
780 // Cleanup is handled in post_run()
781 }
782
783 // Shared teardown for all JavaThreads
784 void JavaThread::post_run() {
785 this->exit(false);
786 this->unregister_thread_stack_with_NMT();
787 // Defer deletion to here to ensure 'this' is still referenceable in call_run
788 // for any shared tear-down.
789 this->smr_delete();
790 }
791
792 static void ensure_join(JavaThread* thread) {
793 // We do not need to grab the Threads_lock, since we are operating on ourself.
794 Handle threadObj(thread, thread->threadObj());
795 assert(threadObj.not_null(), "java thread object must exist");
796 ObjectLocker lock(threadObj, thread);
797 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
798 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
799 // Clear the native thread instance - this makes isAlive return false and allows the join()
800 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
801 // requirements.
802 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
803 java_lang_Thread::release_set_thread(threadObj(), nullptr);
804 lock.notify_all(thread);
805 // Ignore pending exception, since we are exiting anyway
806 thread->clear_pending_exception();
807 }
808
809 static bool is_daemon(oop threadObj) {
810 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
811 }
812
813 // For any new cleanup additions, please check to see if they need to be applied to
814 // cleanup_failed_attach_current_thread as well.
815 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
816 assert(this == JavaThread::current(), "thread consistency check");
817 assert(!is_exiting(), "should not be exiting or terminated already");
818
819 elapsedTimer _timer_exit_phase1;
820 elapsedTimer _timer_exit_phase2;
821 elapsedTimer _timer_exit_phase3;
822 elapsedTimer _timer_exit_phase4;
823
824 om_clear_monitor_cache();
825
826 if (log_is_enabled(Debug, os, thread, timer)) {
827 _timer_exit_phase1.start();
828 }
829
830 HandleMark hm(this);
831 Handle uncaught_exception(this, this->pending_exception());
832 this->clear_pending_exception();
833 Handle threadObj(this, this->threadObj());
834 assert(threadObj.not_null(), "Java thread object should be created");
835
836 if (!destroy_vm) {
837 if (uncaught_exception.not_null()) {
838 EXCEPTION_MARK;
839 // Call method Thread.dispatchUncaughtException().
840 Klass* thread_klass = vmClasses::Thread_klass();
841 JavaValue result(T_VOID);
842 JavaCalls::call_virtual(&result,
843 threadObj, thread_klass,
844 vmSymbols::dispatchUncaughtException_name(),
845 vmSymbols::throwable_void_signature(),
846 uncaught_exception,
847 THREAD);
848 if (HAS_PENDING_EXCEPTION) {
849 ResourceMark rm(this);
850 jio_fprintf(defaultStream::error_stream(),
851 "\nException: %s thrown from the UncaughtExceptionHandler"
852 " in thread \"%s\"\n",
853 pending_exception()->klass()->external_name(),
854 name());
855 CLEAR_PENDING_EXCEPTION;
856 }
857 }
858
859 if (!is_Compiler_thread()) {
860 // We have finished executing user-defined Java code and now have to do the
861 // implementation specific clean-up by calling Thread.exit(). We prevent any
862 // asynchronous exceptions from being delivered while in Thread.exit()
863 // to ensure the clean-up is not corrupted.
864 NoAsyncExceptionDeliveryMark _no_async(this);
865
866 EXCEPTION_MARK;
867 JavaValue result(T_VOID);
868 Klass* thread_klass = vmClasses::Thread_klass();
869 JavaCalls::call_virtual(&result,
870 threadObj, thread_klass,
871 vmSymbols::exit_method_name(),
872 vmSymbols::void_method_signature(),
873 THREAD);
874 CLEAR_PENDING_EXCEPTION;
875 }
876
877 // notify JVMTI
878 if (JvmtiExport::should_post_thread_life()) {
879 JvmtiExport::post_thread_end(this);
880 }
881 } else {
882 // before_exit() has already posted JVMTI THREAD_END events
883 }
884
885 // Cleanup any pending async exception now since we cannot access oops after
886 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
887 if (has_async_exception_condition()) {
888 handshake_state()->clean_async_exception_operation();
889 }
890
891 // The careful dance between thread suspension and exit is handled here.
892 // Since we are in thread_in_vm state and suspension is done with handshakes,
893 // we can just put in the exiting state and it will be correctly handled.
894 // Also, no more async exceptions will be added to the queue after this point.
895 set_terminated(_thread_exiting);
896 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
897
898 if (log_is_enabled(Debug, os, thread, timer)) {
899 _timer_exit_phase1.stop();
900 _timer_exit_phase2.start();
901 }
902
903 // Capture daemon status before the thread is marked as terminated.
904 bool daemon = is_daemon(threadObj());
905
906 // Notify waiters on thread object. This has to be done after exit() is called
907 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
908 // group should have the destroyed bit set before waiters are notified).
909 ensure_join(this);
910 assert(!this->has_pending_exception(), "ensure_join should have cleared");
911
912 if (log_is_enabled(Debug, os, thread, timer)) {
913 _timer_exit_phase2.stop();
914 _timer_exit_phase3.start();
915 }
916 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
917 // held by this thread must be released. The spec does not distinguish
918 // between JNI-acquired and regular Java monitors. We can only see
919 // regular Java monitors here if monitor enter-exit matching is broken.
920 //
921 // ensure_join() ignores IllegalThreadStateExceptions, and so does
922 // ObjectSynchronizer::release_monitors_owned_by_thread().
923 if (exit_type == jni_detach) {
924 // Sanity check even though JNI DetachCurrentThread() would have
925 // returned JNI_ERR if there was a Java frame. JavaThread exit
926 // should be done executing Java code by the time we get here.
927 assert(!this->has_last_Java_frame(),
928 "should not have a Java frame when detaching or exiting");
929 ObjectSynchronizer::release_monitors_owned_by_thread(this);
930 assert(!this->has_pending_exception(), "release_monitors should have cleared");
931 // Check for monitor counts being out of sync.
932 assert(held_monitor_count() == jni_monitor_count(),
933 "held monitor count should be equal to jni: %zd != %zd",
934 held_monitor_count(), jni_monitor_count());
935 // All in-use monitors, including JNI-locked ones, should have been released above.
936 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
937 held_monitor_count());
938 } else {
939 // Check for monitor counts being out of sync.
940 assert(held_monitor_count() == jni_monitor_count(),
941 "held monitor count should be equal to jni: %zd != %zd",
942 held_monitor_count(), jni_monitor_count());
943 // It is possible that a terminating thread failed to unlock monitors it locked
944 // via JNI so we don't assert the count is zero.
945 }
946
947 if (CheckJNICalls && jni_monitor_count() > 0) {
948 // We would like a fatal here, but due to we never checked this before there
949 // is a lot of tests which breaks, even with an error log.
950 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
951 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
952 }
953
954 // These things needs to be done while we are still a Java Thread. Make sure that thread
955 // is in a consistent state, in case GC happens
956 JFR_ONLY(Jfr::on_thread_exit(this);)
957
958 if (active_handles() != nullptr) {
959 JNIHandleBlock* block = active_handles();
960 set_active_handles(nullptr);
961 JNIHandleBlock::release_block(block);
962 }
963
964 if (free_handle_block() != nullptr) {
965 JNIHandleBlock* block = free_handle_block();
966 set_free_handle_block(nullptr);
967 JNIHandleBlock::release_block(block);
968 }
969
970 // These have to be removed while this is still a valid thread.
971 _stack_overflow_state.remove_stack_guard_pages();
972
973 if (UseTLAB) {
974 retire_tlab();
975 }
976
977 if (JvmtiEnv::environments_might_exist()) {
978 JvmtiExport::cleanup_thread(this);
979 }
980
981 // We need to cache the thread name for logging purposes below as once
982 // we have called on_thread_detach this thread must not access any oops.
983 char* thread_name = nullptr;
984 if (log_is_enabled(Debug, os, thread, timer)) {
985 ResourceMark rm(this);
986 thread_name = os::strdup(name());
987 }
988
989 if (log_is_enabled(Info, os, thread)) {
990 ResourceMark rm(this);
991 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
992 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
993 name(), os::current_thread_id());
994 }
995
996 if (log_is_enabled(Debug, os, thread, timer)) {
997 _timer_exit_phase3.stop();
998 _timer_exit_phase4.start();
999 }
1000
1001 #if INCLUDE_JVMCI
1002 if (JVMCICounterSize > 0) {
1003 if (jvmci_counters_include(this)) {
1004 for (int i = 0; i < JVMCICounterSize; i++) {
1005 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1006 }
1007 }
1008 }
1009 #endif // INCLUDE_JVMCI
1010
1011 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1012 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1013 Threads::remove(this, daemon);
1014
1015 if (log_is_enabled(Debug, os, thread, timer)) {
1016 _timer_exit_phase4.stop();
1017 log_debug(os, thread, timer)("name='%s'"
1018 ", exit-phase1=" JLONG_FORMAT
1019 ", exit-phase2=" JLONG_FORMAT
1020 ", exit-phase3=" JLONG_FORMAT
1021 ", exit-phase4=" JLONG_FORMAT,
1022 thread_name,
1023 _timer_exit_phase1.milliseconds(),
1024 _timer_exit_phase2.milliseconds(),
1025 _timer_exit_phase3.milliseconds(),
1026 _timer_exit_phase4.milliseconds());
1027 os::free(thread_name);
1028 }
1029 }
1030
1031 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1032 if (active_handles() != nullptr) {
1033 JNIHandleBlock* block = active_handles();
1034 set_active_handles(nullptr);
1035 JNIHandleBlock::release_block(block);
1036 }
1037
1038 if (free_handle_block() != nullptr) {
1039 JNIHandleBlock* block = free_handle_block();
1040 set_free_handle_block(nullptr);
1041 JNIHandleBlock::release_block(block);
1042 }
1043
1044 // These have to be removed while this is still a valid thread.
1045 _stack_overflow_state.remove_stack_guard_pages();
1046
1047 if (UseTLAB) {
1048 retire_tlab();
1049 }
1050
1051 Threads::remove(this, is_daemon);
1052 }
1053
1054 JavaThread* JavaThread::active() {
1055 Thread* thread = Thread::current();
1056 if (thread->is_Java_thread()) {
1057 return JavaThread::cast(thread);
1058 } else {
1059 assert(thread->is_VM_thread(), "this must be a vm thread");
1060 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1061 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1062 return ret;
1063 }
1064 }
1065
1066 oop JavaThread::exception_oop() const {
1067 return AtomicAccess::load(&_exception_oop);
1068 }
1069
1070 void JavaThread::set_exception_oop(oop o) {
1071 AtomicAccess::store(&_exception_oop, o);
1072 }
1073
1074 void JavaThread::handle_special_runtime_exit_condition() {
1075 if (is_obj_deopt_suspend()) {
1076 frame_anchor()->make_walkable();
1077 wait_for_object_deoptimization();
1078 }
1079 }
1080
1081
1082 // Asynchronous exceptions support
1083 //
1084 void JavaThread::handle_async_exception(oop java_throwable) {
1085 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1086 assert(!is_at_poll_safepoint(), "should have never called this method");
1087
1088 if (has_last_Java_frame()) {
1089 frame f = last_frame();
1090 if (f.is_runtime_frame()) {
1091 // If the topmost frame is a runtime stub, then we are calling into
1092 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1093 // must deoptimize the caller before continuing, as the compiled exception
1094 // handler table may not be valid.
1095 RegisterMap reg_map(this,
1096 RegisterMap::UpdateMap::skip,
1097 RegisterMap::ProcessFrames::include,
1098 RegisterMap::WalkContinuation::skip);
1099 frame compiled_frame = f.sender(®_map);
1100 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1101 Deoptimization::deoptimize(this, compiled_frame);
1102 }
1103 }
1104 }
1105
1106 // We cannot call Exceptions::_throw(...) here because we cannot block
1107 set_pending_exception(java_throwable, __FILE__, __LINE__);
1108
1109 clear_scopedValueBindings();
1110
1111 LogTarget(Info, exceptions) lt;
1112 if (lt.is_enabled()) {
1113 ResourceMark rm;
1114 LogStream ls(lt);
1115 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1116 if (has_last_Java_frame()) {
1117 frame f = last_frame();
1118 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1119 }
1120 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1121 }
1122 }
1123
1124 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1125 // Do not throw asynchronous exceptions against the compiler thread
1126 // or if the thread is already exiting.
1127 if (!can_call_java() || is_exiting()) {
1128 delete aehc;
1129 return;
1130 }
1131
1132 oop exception = aehc->exception();
1133 Handshake::execute(aehc, this); // Install asynchronous handshake
1134
1135 ResourceMark rm;
1136 if (log_is_enabled(Info, exceptions)) {
1137 log_info(exceptions)("Pending Async. exception installed of type: %s",
1138 exception->klass()->external_name());
1139 }
1140 // for AbortVMOnException flag
1141 Exceptions::debug_check_abort(exception->klass()->external_name());
1142
1143 oop vt_oop = vthread();
1144 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1145 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1146 this->interrupt();
1147 }
1148 }
1149
1150 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1151 AsyncExceptionHandshakeClosure* _aehc;
1152 public:
1153 InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1154 HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1155 ~InstallAsyncExceptionHandshakeClosure() {
1156 // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1157 delete _aehc;
1158 }
1159 void do_thread(Thread* thr) {
1160 JavaThread* target = JavaThread::cast(thr);
1161 target->install_async_exception(_aehc);
1162 _aehc = nullptr;
1163 }
1164 };
1165
1166 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1167 OopHandle e(Universe::vm_global(), java_throwable);
1168 InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1169 Handshake::execute(&iaeh, target);
1170 }
1171
1172 #if INCLUDE_JVMTI
1173 void JavaThread::set_is_in_VTMS_transition(bool val) {
1174 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1175 _is_in_VTMS_transition = val;
1176 }
1177
1178 #ifdef ASSERT
1179 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1180 _is_VTMS_transition_disabler = val;
1181 }
1182 #endif
1183 #endif
1184
1185 // External suspension mechanism.
1186 //
1187 // Guarantees on return (for a valid target thread):
1188 // - Target thread will not execute any new bytecode.
1189 // - Target thread will not enter any new monitors.
1190 //
1191 bool JavaThread::java_suspend(bool register_vthread_SR) {
1192 #if INCLUDE_JVMTI
1193 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1194 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1195 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1196 #endif
1197
1198 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1199 "target JavaThread is not protected in calling context.");
1200 return this->suspend_resume_manager()->suspend(register_vthread_SR);
1201 }
1202
1203 bool JavaThread::java_resume(bool register_vthread_SR) {
1204 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1205 "missing ThreadsListHandle in calling context.");
1206 return this->suspend_resume_manager()->resume(register_vthread_SR);
1207 }
1208
1209 // Wait for another thread to perform object reallocation and relocking on behalf of
1210 // this thread. The current thread is required to change to _thread_blocked in order
1211 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1212 // handshake safe, the other thread can complete the handshake used to synchronize
1213 // with this thread and then perform the reallocation and relocking.
1214 // See EscapeBarrier::sync_and_suspend_*()
1215
1216 void JavaThread::wait_for_object_deoptimization() {
1217 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1218 assert(this == Thread::current(), "invariant");
1219
1220 bool spin_wait = os::is_MP();
1221 do {
1222 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1223 // Wait for object deoptimization if requested.
1224 if (spin_wait) {
1225 // A single deoptimization is typically very short. Microbenchmarks
1226 // showed 5% better performance when spinning.
1227 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1228 SpinYield spin(spin_limit);
1229 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1230 spin.wait();
1231 }
1232 // Spin just once
1233 spin_wait = false;
1234 } else {
1235 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1236 if (is_obj_deopt_suspend()) {
1237 ml.wait();
1238 }
1239 }
1240 // A handshake for obj. deoptimization suspend could have been processed so
1241 // we must check after processing.
1242 } while (is_obj_deopt_suspend());
1243 }
1244
1245 #ifdef ASSERT
1246 // Verify the JavaThread has not yet been published in the Threads::list, and
1247 // hence doesn't need protection from concurrent access at this stage.
1248 void JavaThread::verify_not_published() {
1249 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1250 // since an unpublished JavaThread doesn't participate in the
1251 // Thread-SMR protocol for keeping a ThreadsList alive.
1252 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1253 }
1254 #endif
1255
1256 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1257 // pending, when _suspend_flags is non-zero or when we need to process a stack
1258 // watermark. Also check for pending async exceptions (except unsafe access error).
1259 // Note only the native==>Java barriers can call this function when thread state
1260 // is _thread_in_native_trans.
1261 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1262 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1263 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1264
1265 thread->set_thread_state(_thread_in_vm);
1266
1267 // Enable WXWrite: called directly from interpreter native wrapper.
1268 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1269
1270 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1271
1272 // After returning from native, it could be that the stack frames are not
1273 // yet safe to use. We catch such situations in the subsequent stack watermark
1274 // barrier, which will trap unsafe stack frames.
1275 StackWatermarkSet::before_unwind(thread);
1276 }
1277
1278 #ifndef PRODUCT
1279 // Deoptimization
1280 // Function for testing deoptimization
1281 void JavaThread::deoptimize() {
1282 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1283 bool deopt = false; // Dump stack only if a deopt actually happens.
1284 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1285 // Iterate over all frames in the thread and deoptimize
1286 for (; !fst.is_done(); fst.next()) {
1287 if (fst.current()->can_be_deoptimized()) {
1288
1289 if (only_at) {
1290 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1291 // consists of comma or carriage return separated numbers so
1292 // search for the current bci in that string.
1293 address pc = fst.current()->pc();
1294 nmethod* nm = fst.current()->cb()->as_nmethod();
1295 ScopeDesc* sd = nm->scope_desc_at(pc);
1296 char buffer[8];
1297 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1298 size_t len = strlen(buffer);
1299 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1300 while (found != nullptr) {
1301 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1302 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1303 // Check that the bci found is bracketed by terminators.
1304 break;
1305 }
1306 found = strstr(found + 1, buffer);
1307 }
1308 if (!found) {
1309 continue;
1310 }
1311 }
1312
1313 if (DebugDeoptimization && !deopt) {
1314 deopt = true; // One-time only print before deopt
1315 tty->print_cr("[BEFORE Deoptimization]");
1316 trace_frames();
1317 trace_stack();
1318 }
1319 Deoptimization::deoptimize(this, *fst.current());
1320 }
1321 }
1322
1323 if (DebugDeoptimization && deopt) {
1324 tty->print_cr("[AFTER Deoptimization]");
1325 trace_frames();
1326 }
1327 }
1328
1329
1330 // Make zombies
1331 void JavaThread::make_zombies() {
1332 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1333 if (fst.current()->can_be_deoptimized()) {
1334 // it is a Java nmethod
1335 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1336 assert(nm != nullptr, "did not find nmethod");
1337 nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1338 }
1339 }
1340 }
1341 #endif // PRODUCT
1342
1343
1344 void JavaThread::deoptimize_marked_methods() {
1345 if (!has_last_Java_frame()) return;
1346 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1347 for (; !fst.is_done(); fst.next()) {
1348 if (fst.current()->should_be_deoptimized()) {
1349 Deoptimization::deoptimize(this, *fst.current());
1350 }
1351 }
1352 }
1353
1354 #ifdef ASSERT
1355 void JavaThread::verify_frame_info() {
1356 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1357 (has_last_Java_frame() && java_call_counter() > 0),
1358 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1359 has_last_Java_frame() ? "true" : "false", java_call_counter());
1360 }
1361 #endif
1362
1363 // Push on a new block of JNI handles.
1364 void JavaThread::push_jni_handle_block() {
1365 // Allocate a new block for JNI handles.
1366 // Inlined code from jni_PushLocalFrame()
1367 JNIHandleBlock* old_handles = active_handles();
1368 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1369 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1370 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1371 set_active_handles(new_handles);
1372 }
1373
1374 // Pop off the current block of JNI handles.
1375 void JavaThread::pop_jni_handle_block() {
1376 // Release our JNI handle block
1377 JNIHandleBlock* old_handles = active_handles();
1378 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1379 assert(new_handles != nullptr, "should never set active handles to null");
1380 set_active_handles(new_handles);
1381 old_handles->set_pop_frame_link(nullptr);
1382 JNIHandleBlock::release_block(old_handles, this);
1383 }
1384
1385 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1386 // Verify that the deferred card marks have been flushed.
1387 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1388
1389 // Traverse the GCHandles
1390 Thread::oops_do_no_frames(f, cf);
1391
1392 if (active_handles() != nullptr) {
1393 active_handles()->oops_do(f);
1394 }
1395
1396 DEBUG_ONLY(verify_frame_info();)
1397
1398 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1399 // If we have deferred set_locals there might be oops waiting to be
1400 // written
1401 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1402 if (list != nullptr) {
1403 for (int i = 0; i < list->length(); i++) {
1404 list->at(i)->oops_do(f);
1405 }
1406 }
1407
1408 // Traverse instance variables at the end since the GC may be moving things
1409 // around using this function
1410 f->do_oop((oop*) &_vm_result_oop);
1411 f->do_oop((oop*) &_exception_oop);
1412 #if INCLUDE_JVMCI
1413 f->do_oop((oop*) &_jvmci_reserved_oop0);
1414
1415 if (_live_nmethod != nullptr && cf != nullptr) {
1416 cf->do_nmethod(_live_nmethod);
1417 }
1418 #endif
1419
1420 if (jvmti_thread_state() != nullptr) {
1421 jvmti_thread_state()->oops_do(f, cf);
1422 }
1423
1424 // The continuation oops are really on the stack. But there is typically at most
1425 // one of those per thread, so we handle them here in the oops_do_no_frames part
1426 // so that we don't have to sprinkle as many stack watermark checks where these
1427 // oops are used. We just need to make sure the thread has started processing.
1428 ContinuationEntry* entry = _cont_entry;
1429 while (entry != nullptr) {
1430 f->do_oop((oop*)entry->cont_addr());
1431 f->do_oop((oop*)entry->chunk_addr());
1432 entry = entry->parent();
1433 }
1434
1435 // Due to lightweight locking
1436 lock_stack().oops_do(f);
1437 }
1438
1439 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1440 if (!has_last_Java_frame()) {
1441 return;
1442 }
1443 // Finish any pending lazy GC activity for the frames
1444 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1445 // Traverse the execution stack
1446 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1447 fst.current()->oops_do(f, cf, fst.register_map());
1448 }
1449 }
1450
1451 #ifdef ASSERT
1452 void JavaThread::verify_states_for_handshake() {
1453 // This checks that the thread has a correct frame state during a handshake.
1454 verify_frame_info();
1455 }
1456 #endif
1457
1458 void JavaThread::nmethods_do(NMethodClosure* cf) {
1459 DEBUG_ONLY(verify_frame_info();)
1460 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1461
1462 if (has_last_Java_frame()) {
1463 // Traverse the execution stack
1464 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1465 fst.current()->nmethod_do(cf);
1466 }
1467 }
1468
1469 if (jvmti_thread_state() != nullptr) {
1470 jvmti_thread_state()->nmethods_do(cf);
1471 }
1472
1473 #if INCLUDE_JVMCI
1474 if (_live_nmethod != nullptr) {
1475 cf->do_nmethod(_live_nmethod);
1476 }
1477 #endif
1478 }
1479
1480 void JavaThread::metadata_do(MetadataClosure* f) {
1481 if (has_last_Java_frame()) {
1482 // Traverse the execution stack to call f() on the methods in the stack
1483 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1484 fst.current()->metadata_do(f);
1485 }
1486 } else if (is_Compiler_thread()) {
1487 // need to walk ciMetadata in current compile tasks to keep alive.
1488 CompilerThread* ct = (CompilerThread*)this;
1489 if (ct->env() != nullptr) {
1490 ct->env()->metadata_do(f);
1491 }
1492 CompileTask* task = ct->task();
1493 if (task != nullptr) {
1494 task->metadata_do(f);
1495 }
1496 }
1497 }
1498
1499 // Printing
1500 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1501 switch (_thread_state) {
1502 case _thread_uninitialized: return "_thread_uninitialized";
1503 case _thread_new: return "_thread_new";
1504 case _thread_new_trans: return "_thread_new_trans";
1505 case _thread_in_native: return "_thread_in_native";
1506 case _thread_in_native_trans: return "_thread_in_native_trans";
1507 case _thread_in_vm: return "_thread_in_vm";
1508 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1509 case _thread_in_Java: return "_thread_in_Java";
1510 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1511 case _thread_blocked: return "_thread_blocked";
1512 case _thread_blocked_trans: return "_thread_blocked_trans";
1513 default: return "unknown thread state";
1514 }
1515 }
1516
1517 void JavaThread::print_thread_state_on(outputStream *st) const {
1518 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1519 }
1520
1521 // Called by Threads::print() for VM_PrintThreads operation
1522 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1523 st->print_raw("\"");
1524 st->print_raw(name());
1525 st->print_raw("\" ");
1526 oop thread_oop = threadObj();
1527 if (thread_oop != nullptr) {
1528 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1529 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1530 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1531 }
1532 Thread::print_on(st, print_extended_info);
1533 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1534 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1535 if (thread_oop != nullptr) {
1536 if (is_vthread_mounted()) {
1537 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1538 } else {
1539 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1540 }
1541 }
1542 #ifndef PRODUCT
1543 _safepoint_state->print_on(st);
1544 #endif // PRODUCT
1545 if (is_Compiler_thread()) {
1546 CompileTask *task = ((CompilerThread*)this)->task();
1547 if (task != nullptr) {
1548 st->print(" Compiling: ");
1549 task->print(st, nullptr, true, false);
1550 } else {
1551 st->print(" No compile task");
1552 }
1553 st->cr();
1554 }
1555 }
1556
1557 void JavaThread::print() const { print_on(tty); }
1558
1559 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1560 st->print("%s", get_thread_name_string(buf, buflen));
1561 }
1562
1563 // Called by fatal error handler. The difference between this and
1564 // JavaThread::print() is that we can't grab lock or allocate memory.
1565 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1566 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1567 Thread* current = Thread::current_or_null_safe();
1568 assert(current != nullptr, "cannot be called by a detached thread");
1569 st->fill_to(60);
1570 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1571 // Only access threadObj() if current thread is not a JavaThread
1572 // or if it is a JavaThread that can safely access oops.
1573 oop thread_obj = threadObj();
1574 if (thread_obj != nullptr) {
1575 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1576 }
1577 }
1578 st->print(" [");
1579 st->print("%s", _get_thread_state_name(_thread_state));
1580 if (osthread()) {
1581 st->print(", id=%d", osthread()->thread_id());
1582 }
1583 // Use raw field members for stack base/size as this could be
1584 // called before a thread has run enough to initialize them.
1585 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1586 p2i(_stack_base - _stack_size), p2i(_stack_base),
1587 PROPERFMTARGS(_stack_size));
1588 st->print("]");
1589
1590 ThreadsSMRSupport::print_info_on(this, st);
1591 return;
1592 }
1593
1594
1595 // Verification
1596
1597 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1598 // ignore if there is no stack
1599 if (!has_last_Java_frame()) return;
1600 // traverse the stack frames. Starts from top frame.
1601 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1602 frame* fr = fst.current();
1603 f(fr, fst.register_map());
1604 }
1605 }
1606
1607 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1608
1609 void JavaThread::verify() {
1610 // Verify oops in the thread.
1611 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1612
1613 // Verify the stack frames.
1614 frames_do(frame_verify);
1615 }
1616
1617 // CR 6300358 (sub-CR 2137150)
1618 // Most callers of this method assume that it can't return null but a
1619 // thread may not have a name whilst it is in the process of attaching to
1620 // the VM - see CR 6412693, and there are places where a JavaThread can be
1621 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1622 // if vm exit occurs during initialization). These cases can all be accounted
1623 // for such that this method never returns null.
1624 const char* JavaThread::name() const {
1625 if (Thread::is_JavaThread_protected(/* target */ this)) {
1626 // The target JavaThread is protected so get_thread_name_string() is safe:
1627 return get_thread_name_string();
1628 }
1629
1630 // The target JavaThread is not protected so we return the default:
1631 return Thread::name();
1632 }
1633
1634 // Like name() but doesn't include the protection check. This must only be
1635 // called when it is known to be safe, even though the protection check can't tell
1636 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1637 const char* JavaThread::name_raw() const {
1638 return get_thread_name_string();
1639 }
1640
1641 // Returns a non-null representation of this thread's name, or a suitable
1642 // descriptive string if there is no set name.
1643 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1644 const char* name_str;
1645 #ifdef ASSERT
1646 Thread* current = Thread::current_or_null_safe();
1647 assert(current != nullptr, "cannot be called by a detached thread");
1648 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1649 // Only access threadObj() if current thread is not a JavaThread
1650 // or if it is a JavaThread that can safely access oops.
1651 #endif
1652 oop thread_obj = threadObj();
1653 if (thread_obj != nullptr) {
1654 oop name = java_lang_Thread::name(thread_obj);
1655 if (name != nullptr) {
1656 if (buf == nullptr) {
1657 name_str = java_lang_String::as_utf8_string(name);
1658 } else {
1659 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1660 }
1661 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1662 name_str = "<no-name - thread is attaching>";
1663 } else {
1664 name_str = "<un-named>";
1665 }
1666 } else {
1667 name_str = Thread::name();
1668 }
1669 #ifdef ASSERT
1670 } else {
1671 // Current JavaThread has exited...
1672 if (current == this) {
1673 // ... and is asking about itself:
1674 name_str = "<no-name - current JavaThread has exited>";
1675 } else {
1676 // ... and it can't safely determine this JavaThread's name so
1677 // use the default thread name.
1678 name_str = Thread::name();
1679 }
1680 }
1681 #endif
1682 assert(name_str != nullptr, "unexpected null thread name");
1683 return name_str;
1684 }
1685
1686 // Helper to extract the name from the thread oop for logging.
1687 const char* JavaThread::name_for(oop thread_obj) {
1688 assert(thread_obj != nullptr, "precondition");
1689 oop name = java_lang_Thread::name(thread_obj);
1690 const char* name_str;
1691 if (name != nullptr) {
1692 name_str = java_lang_String::as_utf8_string(name);
1693 } else {
1694 name_str = "<un-named>";
1695 }
1696 return name_str;
1697 }
1698
1699 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1700
1701 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1702 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1703 // Link Java Thread object <-> C++ Thread
1704
1705 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1706 // and put it into a new Handle. The Handle "thread_oop" can then
1707 // be used to pass the C++ thread object to other methods.
1708
1709 // Set the Java level thread object (jthread) field of the
1710 // new thread (a JavaThread *) to C++ thread object using the
1711 // "thread_oop" handle.
1712
1713 // Set the thread field (a JavaThread *) of the
1714 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1715
1716 Handle thread_oop(Thread::current(),
1717 JNIHandles::resolve_non_null(jni_thread));
1718 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1719 "must be initialized");
1720 set_threadOopHandles(thread_oop());
1721 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1722
1723 if (prio == NoPriority) {
1724 prio = java_lang_Thread::priority(thread_oop());
1725 assert(prio != NoPriority, "A valid priority should be present");
1726 }
1727
1728 // Push the Java priority down to the native thread; needs Threads_lock
1729 Thread::set_priority(this, prio);
1730
1731 // Add the new thread to the Threads list and set it in motion.
1732 // We must have threads lock in order to call Threads::add.
1733 // It is crucial that we do not block before the thread is
1734 // added to the Threads list for if a GC happens, then the java_thread oop
1735 // will not be visited by GC.
1736 Threads::add(this);
1737 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1738 // on a ThreadsList. We don't want to wait for the release when the
1739 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1740 // is already visible to JVM/TI via the ThreadsList.
1741 java_lang_Thread::release_set_thread(thread_oop(), this);
1742 }
1743
1744 oop JavaThread::current_park_blocker() {
1745 // Support for JSR-166 locks
1746 oop thread_oop = threadObj();
1747 if (thread_oop != nullptr) {
1748 return java_lang_Thread::park_blocker(thread_oop);
1749 }
1750 return nullptr;
1751 }
1752
1753 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1754 // This is the external format, selecting the platform or vthread
1755 // as applicable, and allowing for a native-only stack.
1756 void JavaThread::print_jni_stack() {
1757 assert(this == JavaThread::current(), "Can't print stack of other threads");
1758 if (!has_last_Java_frame()) {
1759 ResourceMark rm(this);
1760 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1761 if (buf == nullptr) {
1762 tty->print_cr("Unable to print native stack - out of memory");
1763 return;
1764 }
1765 NativeStackPrinter nsp(this);
1766 address lastpc = nullptr;
1767 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1768 true /*print_source_info */, -1 /* max stack */ );
1769 } else {
1770 print_active_stack_on(tty);
1771 }
1772 }
1773
1774 void JavaThread::print_stack_on(outputStream* st) {
1775 if (!has_last_Java_frame()) return;
1776
1777 Thread* current_thread = Thread::current();
1778 ResourceMark rm(current_thread);
1779 HandleMark hm(current_thread);
1780
1781 RegisterMap reg_map(this,
1782 RegisterMap::UpdateMap::include,
1783 RegisterMap::ProcessFrames::include,
1784 RegisterMap::WalkContinuation::skip);
1785 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1786 int count = 0;
1787 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1788 if (f->is_java_frame()) {
1789 javaVFrame* jvf = javaVFrame::cast(f);
1790 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1791
1792 // Print out lock information
1793 if (JavaMonitorsInStackTrace) {
1794 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1795 }
1796 } else {
1797 // Ignore non-Java frames
1798 }
1799
1800 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1801 count++;
1802 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1803 }
1804 }
1805
1806 void JavaThread::print_vthread_stack_on(outputStream* st) {
1807 assert(is_vthread_mounted(), "Caller should have checked this");
1808 assert(has_last_Java_frame(), "must be");
1809
1810 Thread* current_thread = Thread::current();
1811 ResourceMark rm(current_thread);
1812 HandleMark hm(current_thread);
1813
1814 RegisterMap reg_map(this,
1815 RegisterMap::UpdateMap::include,
1816 RegisterMap::ProcessFrames::include,
1817 RegisterMap::WalkContinuation::include);
1818 ContinuationEntry* cont_entry = last_continuation();
1819 vframe* start_vf = last_java_vframe(®_map);
1820 int count = 0;
1821 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1822 // Watch for end of vthread stack
1823 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1824 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1825 if (cont_entry->is_virtual_thread()) {
1826 break;
1827 }
1828 cont_entry = cont_entry->parent();
1829 }
1830 if (f->is_java_frame()) {
1831 javaVFrame* jvf = javaVFrame::cast(f);
1832 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1833
1834 // Print out lock information
1835 if (JavaMonitorsInStackTrace) {
1836 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1837 }
1838 } else {
1839 // Ignore non-Java frames
1840 }
1841
1842 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1843 count++;
1844 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1845 }
1846 }
1847
1848 void JavaThread::print_active_stack_on(outputStream* st) {
1849 if (is_vthread_mounted()) {
1850 print_vthread_stack_on(st);
1851 } else {
1852 print_stack_on(st);
1853 }
1854 }
1855
1856 #if INCLUDE_JVMTI
1857 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1858 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1859 set_jvmti_vthread(thread_oop);
1860
1861 // unbind current JvmtiThreadState from JavaThread
1862 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1863
1864 // bind new JvmtiThreadState to JavaThread
1865 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1866
1867 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1868 JvmtiThreadState::process_pending_interp_only(this);
1869
1870 return jvmti_thread_state();
1871 }
1872 #endif
1873
1874 // JVMTI PopFrame support
1875 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1876 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1877 if (in_bytes(size_in_bytes) != 0) {
1878 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1879 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1880 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1881 }
1882 }
1883
1884 void* JavaThread::popframe_preserved_args() {
1885 return _popframe_preserved_args;
1886 }
1887
1888 ByteSize JavaThread::popframe_preserved_args_size() {
1889 return in_ByteSize(_popframe_preserved_args_size);
1890 }
1891
1892 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1893 int sz = in_bytes(popframe_preserved_args_size());
1894 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1895 return in_WordSize(sz / wordSize);
1896 }
1897
1898 void JavaThread::popframe_free_preserved_args() {
1899 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1900 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1901 _popframe_preserved_args = nullptr;
1902 _popframe_preserved_args_size = 0;
1903 }
1904
1905 #ifndef PRODUCT
1906
1907 void JavaThread::trace_frames() {
1908 tty->print_cr("[Describe stack]");
1909 int frame_no = 1;
1910 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1911 tty->print(" %d. ", frame_no++);
1912 fst.current()->print_value_on(tty);
1913 tty->cr();
1914 }
1915 }
1916
1917 class PrintAndVerifyOopClosure: public OopClosure {
1918 protected:
1919 template <class T> inline void do_oop_work(T* p) {
1920 oop obj = RawAccess<>::oop_load(p);
1921 if (obj == nullptr) return;
1922 tty->print(INTPTR_FORMAT ": ", p2i(p));
1923 if (oopDesc::is_oop_or_null(obj)) {
1924 if (obj->is_objArray()) {
1925 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1926 } else {
1927 obj->print();
1928 }
1929 } else {
1930 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1931 }
1932 tty->cr();
1933 }
1934 public:
1935 virtual void do_oop(oop* p) { do_oop_work(p); }
1936 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1937 };
1938
1939 #ifdef ASSERT
1940 // Print or validate the layout of stack frames
1941 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1942 ResourceMark rm;
1943 PreserveExceptionMark pm(this);
1944 FrameValues values;
1945 int frame_no = 0;
1946 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1947 fst.current()->describe(values, ++frame_no, fst.register_map());
1948 if (depth == frame_no) break;
1949 }
1950 Continuation::describe(values);
1951 if (validate_only) {
1952 values.validate();
1953 } else {
1954 tty->print_cr("[Describe stack layout]");
1955 values.print(this);
1956 }
1957 }
1958 #endif
1959
1960 void JavaThread::trace_stack_from(vframe* start_vf) {
1961 ResourceMark rm;
1962 int vframe_no = 1;
1963 for (vframe* f = start_vf; f; f = f->sender()) {
1964 if (f->is_java_frame()) {
1965 javaVFrame::cast(f)->print_activation(vframe_no++);
1966 } else {
1967 f->print();
1968 }
1969 if (vframe_no > StackPrintLimit) {
1970 tty->print_cr("...<more frames>...");
1971 return;
1972 }
1973 }
1974 }
1975
1976
1977 void JavaThread::trace_stack() {
1978 if (!has_last_Java_frame()) return;
1979 Thread* current_thread = Thread::current();
1980 ResourceMark rm(current_thread);
1981 HandleMark hm(current_thread);
1982 RegisterMap reg_map(this,
1983 RegisterMap::UpdateMap::include,
1984 RegisterMap::ProcessFrames::include,
1985 RegisterMap::WalkContinuation::skip);
1986 trace_stack_from(last_java_vframe(®_map));
1987 }
1988
1989
1990 #endif // PRODUCT
1991
1992 // Slow-path increment of the held monitor counts. JNI locking is always
1993 // this slow-path.
1994 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
1995 #ifdef SUPPORT_MONITOR_COUNT
1996 // Nothing to do. Just do some sanity check.
1997 assert(_held_monitor_count == 0, "counter should not be used");
1998 assert(_jni_monitor_count == 0, "counter should not be used");
1999 #endif // SUPPORT_MONITOR_COUNT
2000 }
2001
2002 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2003 // this slow-path.
2004 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2005 #ifdef SUPPORT_MONITOR_COUNT
2006 // Nothing to do. Just do some sanity check.
2007 assert(_held_monitor_count == 0, "counter should not be used");
2008 assert(_jni_monitor_count == 0, "counter should not be used");
2009 #endif // SUPPORT_MONITOR_COUNT
2010 }
2011
2012 frame JavaThread::vthread_last_frame() {
2013 assert (is_vthread_mounted(), "Virtual thread not mounted");
2014 return last_frame();
2015 }
2016
2017 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2018 const ContinuationEntry* entry = vthread_continuation();
2019 guarantee (entry != nullptr, "Not a carrier thread");
2020 frame f = entry->to_frame();
2021 if (reg_map->process_frames()) {
2022 entry->flush_stack_processing(this);
2023 }
2024 entry->update_register_map(reg_map);
2025 return f.sender(reg_map);
2026 }
2027
2028 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2029 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2030 }
2031
2032 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2033 assert(reg_map != nullptr, "a map must be given");
2034 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2035 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2036 }
2037 return nullptr;
2038 }
2039
2040 Klass* JavaThread::security_get_caller_class(int depth) {
2041 ResetNoHandleMark rnhm;
2042 HandleMark hm(Thread::current());
2043
2044 vframeStream vfst(this);
2045 vfst.security_get_caller_frame(depth);
2046 if (!vfst.at_end()) {
2047 return vfst.method()->method_holder();
2048 }
2049 return nullptr;
2050 }
2051
2052 // Internal convenience function for millisecond resolution sleeps.
2053 bool JavaThread::sleep(jlong millis) {
2054 jlong nanos;
2055 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2056 // Conversion to nanos would overflow, saturate at max
2057 nanos = max_jlong;
2058 } else {
2059 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2060 }
2061 return sleep_nanos(nanos);
2062 }
2063
2064 // java.lang.Thread.sleep support
2065 // Returns true if sleep time elapsed as expected, and false
2066 // if the thread was interrupted or async exception was installed.
2067 bool JavaThread::sleep_nanos(jlong nanos) {
2068 assert(this == Thread::current(), "thread consistency check");
2069 assert(nanos >= 0, "nanos are in range");
2070
2071 ParkEvent * const slp = this->_SleepEvent;
2072 // Because there can be races with thread interruption sending an unpark()
2073 // to the event, we explicitly reset it here to avoid an immediate return.
2074 // The actual interrupt state will be checked before we park().
2075 slp->reset();
2076 // Thread interruption establishes a happens-before ordering in the
2077 // Java Memory Model, so we need to ensure we synchronize with the
2078 // interrupt state.
2079 OrderAccess::fence();
2080
2081 jlong prevtime = os::javaTimeNanos();
2082
2083 jlong nanos_remaining = nanos;
2084
2085 for (;;) {
2086 if (has_async_exception_condition()) {
2087 return false;
2088 }
2089 // interruption has precedence over timing out
2090 if (this->is_interrupted(true)) {
2091 return false;
2092 }
2093
2094 if (nanos_remaining <= 0) {
2095 return true;
2096 }
2097
2098 {
2099 ThreadBlockInVM tbivm(this);
2100 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2101 slp->park_nanos(nanos_remaining);
2102 }
2103
2104 // Update elapsed time tracking
2105 jlong newtime = os::javaTimeNanos();
2106 if (newtime - prevtime < 0) {
2107 // time moving backwards, should only happen if no monotonic clock
2108 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2109 assert(false,
2110 "unexpected time moving backwards detected in JavaThread::sleep()");
2111 } else {
2112 nanos_remaining -= (newtime - prevtime);
2113 }
2114 prevtime = newtime;
2115 }
2116 }
2117
2118 // Last thread running calls java.lang.Shutdown.shutdown()
2119 void JavaThread::invoke_shutdown_hooks() {
2120 HandleMark hm(this);
2121
2122 // We could get here with a pending exception, if so clear it now.
2123 if (this->has_pending_exception()) {
2124 this->clear_pending_exception();
2125 }
2126
2127 EXCEPTION_MARK;
2128 Klass* shutdown_klass =
2129 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2130 THREAD);
2131 if (shutdown_klass != nullptr) {
2132 // SystemDictionary::resolve_or_null will return null if there was
2133 // an exception. If we cannot load the Shutdown class, just don't
2134 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2135 // won't be run. Note that if a shutdown hook was registered,
2136 // the Shutdown class would have already been loaded
2137 // (Runtime.addShutdownHook will load it).
2138 JavaValue result(T_VOID);
2139 JavaCalls::call_static(&result,
2140 shutdown_klass,
2141 vmSymbols::shutdown_name(),
2142 vmSymbols::void_method_signature(),
2143 THREAD);
2144 }
2145 CLEAR_PENDING_EXCEPTION;
2146 }
2147
2148 #ifndef PRODUCT
2149 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2150 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2151 }
2152 #endif
2153
2154 // Helper function to create the java.lang.Thread object for a
2155 // VM-internal thread. The thread will have the given name, and be
2156 // a member of the "system" ThreadGroup.
2157 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2158 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2159
2160 // Initialize thread_oop to put it into the system threadGroup.
2161 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2162 Handle thread_group(THREAD, Universe::system_thread_group());
2163 Handle thread_oop =
2164 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2165 vmSymbols::threadgroup_string_void_signature(),
2166 thread_group,
2167 string,
2168 CHECK_NH);
2169
2170 return thread_oop;
2171 }
2172
2173 // Starts the target JavaThread as a daemon of the given priority, and
2174 // bound to the given java.lang.Thread instance.
2175 // The Threads_lock is held for the duration.
2176 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2177 Handle thread_oop, ThreadPriority prio) {
2178
2179 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2180
2181 MutexLocker mu(current, Threads_lock);
2182
2183 // Initialize the fields of the thread_oop first.
2184 if (prio != NoPriority) {
2185 java_lang_Thread::set_priority(thread_oop(), prio);
2186 // Note: we don't call os::set_priority here. Possibly we should,
2187 // else all threads should call it themselves when they first run.
2188 }
2189
2190 java_lang_Thread::set_daemon(thread_oop());
2191
2192 // Now bind the thread_oop to the target JavaThread.
2193 target->set_threadOopHandles(thread_oop());
2194 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2195
2196 Threads::add(target); // target is now visible for safepoint/handshake
2197 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2198 // on a ThreadsList. We don't want to wait for the release when the
2199 // Theads_lock is dropped when the 'mu' destructor is run since the
2200 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2201
2202 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2203 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2204 Thread::start(target);
2205 }
2206
2207 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2208 // At this point it may be possible that no osthread was created for the
2209 // JavaThread due to lack of resources. However, since this must work
2210 // for critical system threads just check and abort if this fails.
2211 if (thread->osthread() == nullptr) {
2212 // This isn't really an OOM condition, but historically this is what
2213 // we report.
2214 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2215 os::native_thread_creation_failed_msg());
2216 }
2217 }
2218
2219 void JavaThread::pretouch_stack() {
2220 // Given an established java thread stack with usable area followed by
2221 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2222 // from the current frame down to the start of the shadow zone.
2223 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2224 if (is_in_full_stack(end)) {
2225 char* p1 = (char*) alloca(1);
2226 address here = (address) &p1;
2227 if (is_in_full_stack(here) && here > end) {
2228 size_t to_alloc = here - end;
2229 char* p2 = (char*) alloca(to_alloc);
2230 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2231 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2232 os::pretouch_memory(p2, p2 + to_alloc,
2233 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2234 }
2235 }
2236 }
2237
2238 // Deferred OopHandle release support.
2239
2240 class OopHandleList : public CHeapObj<mtInternal> {
2241 static const int _count = 4;
2242 OopHandle _handles[_count];
2243 OopHandleList* _next;
2244 int _index;
2245 public:
2246 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2247 void add(OopHandle h) {
2248 assert(_index < _count, "too many additions");
2249 _handles[_index++] = h;
2250 }
2251 ~OopHandleList() {
2252 assert(_index == _count, "usage error");
2253 for (int i = 0; i < _index; i++) {
2254 _handles[i].release(JavaThread::thread_oop_storage());
2255 }
2256 }
2257 OopHandleList* next() const { return _next; }
2258 };
2259
2260 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2261
2262 // Called by the ServiceThread to do the work of releasing
2263 // the OopHandles.
2264 void JavaThread::release_oop_handles() {
2265 OopHandleList* list;
2266 {
2267 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2268 list = _oop_handle_list;
2269 _oop_handle_list = nullptr;
2270 }
2271 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2272
2273 while (list != nullptr) {
2274 OopHandleList* l = list;
2275 list = l->next();
2276 delete l;
2277 }
2278 }
2279
2280 // Add our OopHandles for later release.
2281 void JavaThread::add_oop_handles_for_release() {
2282 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2283 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2284 new_head->add(_threadObj);
2285 new_head->add(_vthread);
2286 new_head->add(_jvmti_vthread);
2287 new_head->add(_scopedValueCache);
2288 _oop_handle_list = new_head;
2289 Service_lock->notify_all();
2290 }
2291
2292 #if INCLUDE_JFR
2293 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2294 assert(result != freeze_ok, "sanity check");
2295 _last_freeze_fail_result = result;
2296 _last_freeze_fail_time = Ticks::now();
2297 }
2298
2299 // Post jdk.VirtualThreadPinned event
2300 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2301 assert(result != freeze_ok, "sanity check");
2302 if (event->should_commit()) {
2303 char reason[256];
2304 if (class_to_be_initialized() != nullptr) {
2305 ResourceMark rm(this);
2306 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2307 class_to_be_initialized()->external_name());
2308 event->set_pinnedReason(reason);
2309 } else if (class_being_initialized() != nullptr) {
2310 ResourceMark rm(this);
2311 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2312 class_being_initialized()->external_name());
2313 event->set_pinnedReason(reason);
2314 } else if (result == freeze_pinned_native) {
2315 event->set_pinnedReason("Native or VM frame on stack");
2316 } else {
2317 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2318 event->set_pinnedReason(reason);
2319 }
2320 event->set_blockingOperation(op);
2321 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2322 event->commit();
2323 }
2324 }
2325 #endif