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 _at_preemptable_init(false), 500 DEBUG_ONLY(_preempt_init_klass(nullptr) COMMA)
501
502 _handshake(this),
503 _suspend_resume_manager(this, &_handshake._lock),
504
505 _popframe_preserved_args(nullptr),
506 _popframe_preserved_args_size(0),
507
508 _jvmti_thread_state(nullptr),
509 _interp_only_mode(0),
510 _should_post_on_exceptions_flag(JNI_FALSE),
511 _thread_stat(new ThreadStatistics()),
512
513 _parker(),
514
515 _class_to_be_initialized(nullptr),
516 _class_being_initialized(nullptr),
517
518 _SleepEvent(ParkEvent::Allocate(this)),
519
520 #if INCLUDE_JFR
521 _last_freeze_fail_result(freeze_ok),
522 #endif
523
524 _lock_stack(this),
525 _om_cache(this) {
526 set_jni_functions(jni_functions());
527
528 #if INCLUDE_JVMCI
529 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
530 if (JVMCICounterSize > 0) {
531 resize_counters(0, (int) JVMCICounterSize);
532 }
533 #endif // INCLUDE_JVMCI
534
535 // Setup safepoint state info for this thread
536 ThreadSafepointState::create(this);
537
538 SafepointMechanism::initialize_header(this);
539
540 set_requires_cross_modify_fence(false);
541
542 pd_initialize();
543 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
544 }
545
546 JavaThread* JavaThread::create_attaching_thread() {
547 JavaThread* jt = new JavaThread();
548 jt->_jni_attach_state = _attaching_via_jni;
549 return jt;
550 }
551
552 // interrupt support
553
554 void JavaThread::interrupt() {
555 // All callers should have 'this' thread protected by a
556 // ThreadsListHandle so that it cannot terminate and deallocate
557 // itself.
558 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
559
560 // For Windows _interrupt_event
561 WINDOWS_ONLY(osthread()->set_interrupted(true);)
562
563 // For Thread.sleep
564 _SleepEvent->unpark();
565
566 // For JSR166 LockSupport.park
567 parker()->unpark();
568
569 // For ObjectMonitor and JvmtiRawMonitor
570 _ParkEvent->unpark();
571 }
572
573 bool JavaThread::is_interrupted(bool clear_interrupted) {
574 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
575
576 if (_threadObj.peek() == nullptr) {
577 // If there is no j.l.Thread then it is impossible to have
578 // been interrupted. We can find null during VM initialization
579 // or when a JNI thread is still in the process of attaching.
580 // In such cases this must be the current thread.
581 assert(this == Thread::current(), "invariant");
582 return false;
583 }
584
585 bool interrupted = java_lang_Thread::interrupted(threadObj());
586
587 // NOTE that since there is no "lock" around the interrupt and
588 // is_interrupted operations, there is the possibility that the
589 // interrupted flag will be "false" but that the
590 // low-level events will be in the signaled state. This is
591 // intentional. The effect of this is that Object.wait() and
592 // LockSupport.park() will appear to have a spurious wakeup, which
593 // is allowed and not harmful, and the possibility is so rare that
594 // it is not worth the added complexity to add yet another lock.
595 // For the sleep event an explicit reset is performed on entry
596 // to JavaThread::sleep, so there is no early return. It has also been
597 // recommended not to put the interrupted flag into the "event"
598 // structure because it hides the issue.
599 // Also, because there is no lock, we must only clear the interrupt
600 // state if we are going to report that we were interrupted; otherwise
601 // an interrupt that happens just after we read the field would be lost.
602 if (interrupted && clear_interrupted) {
603 assert(this == Thread::current(), "only the current thread can clear");
604 java_lang_Thread::set_interrupted(threadObj(), false);
605 WINDOWS_ONLY(osthread()->set_interrupted(false);)
606 }
607 return interrupted;
608 }
609
610 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
611 // the Java code in Object::wait which are not present in RawMonitorWait.
612 bool JavaThread::get_and_clear_interrupted() {
613 if (!is_interrupted(false)) {
614 return false;
615 }
616 oop thread_oop = vthread_or_thread();
617 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
618
619 if (!is_virtual) {
620 return is_interrupted(true);
621 }
622 // Virtual thread: clear interrupt status for both virtual and
623 // carrier threads under the interruptLock protection.
624 JavaThread* current = JavaThread::current();
625 HandleMark hm(current);
626 Handle thread_h(current, thread_oop);
627 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
628
629 // re-check the interrupt status under the interruptLock protection
630 bool interrupted = java_lang_Thread::interrupted(thread_h());
631
632 if (interrupted) {
633 assert(this == Thread::current(), "only the current thread can clear");
634 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
635 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
636 WINDOWS_ONLY(osthread()->set_interrupted(false);)
637 }
638 return interrupted;
639 }
640
641 void JavaThread::block_if_vm_exited() {
642 if (_terminated == _vm_exited) {
643 // _vm_exited is set at safepoint, and Threads_lock is never released
644 // so we will block here forever.
645 // Here we can be doing a jump from a safe state to an unsafe state without
646 // proper transition, but it happens after the final safepoint has begun so
647 // this jump won't cause any safepoint problems.
648 set_thread_state(_thread_in_vm);
649 Threads_lock->lock();
650 ShouldNotReachHere();
651 }
652 }
653
654 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
655 set_entry_point(entry_point);
656 // Create the native thread itself.
657 // %note runtime_23
658 os::ThreadType thr_type = os::java_thread;
659 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
660 os::java_thread;
661 os::create_thread(this, thr_type, stack_sz);
662 // The _osthread may be null here because we ran out of memory (too many threads active).
663 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
664 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
665 // the exception consists of creating the exception object & initializing it, initialization
666 // will leave the VM via a JavaCall and then all locks must be unlocked).
667 //
668 // The thread is still suspended when we reach here. Thread must be explicit started
669 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
670 // by calling Threads:add. The reason why this is not done here, is because the thread
671 // object must be fully initialized (take a look at JVM_Start)
672 }
673
674 JavaThread::~JavaThread() {
675
676 // Enqueue OopHandles for release by the service thread.
677 add_oop_handles_for_release();
678
679 // Return the sleep event to the free list
680 ParkEvent::Release(_SleepEvent);
681 _SleepEvent = nullptr;
682
683 // Free any remaining previous UnrollBlock
684 vframeArray* old_array = vframe_array_last();
685
686 if (old_array != nullptr) {
687 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
688 old_array->set_unroll_block(nullptr);
689 delete old_info;
690 delete old_array;
691 }
692
693 JvmtiDeferredUpdates* updates = deferred_updates();
694 if (updates != nullptr) {
695 // This can only happen if thread is destroyed before deoptimization occurs.
696 assert(updates->count() > 0, "Updates holder not deleted");
697 // free deferred updates.
698 delete updates;
699 set_deferred_updates(nullptr);
700 }
701
702 // All Java related clean up happens in exit
703 ThreadSafepointState::destroy(this);
704 if (_thread_stat != nullptr) delete _thread_stat;
705
706 #if INCLUDE_JVMCI
707 if (JVMCICounterSize > 0) {
708 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
709 }
710 #endif // INCLUDE_JVMCI
711 }
712
713
714 // First JavaThread specific code executed by a new Java thread.
715 void JavaThread::pre_run() {
716 // empty - see comments in run()
717 }
718
719 // The main routine called by a new Java thread. This isn't overridden
720 // by subclasses, instead different subclasses define a different "entry_point"
721 // which defines the actual logic for that kind of thread.
722 void JavaThread::run() {
723 // initialize thread-local alloc buffer related fields
724 initialize_tlab();
725
726 _stack_overflow_state.create_stack_guard_pages();
727
728 cache_global_variables();
729
730 // Thread is now sufficiently initialized to be handled by the safepoint code as being
731 // in the VM. Change thread state from _thread_new to _thread_in_vm
732 assert(this->thread_state() == _thread_new, "wrong thread state");
733 set_thread_state(_thread_in_vm);
734
735 // Before a thread is on the threads list it is always safe, so after leaving the
736 // _thread_new we should emit a instruction barrier. The distance to modified code
737 // from here is probably far enough, but this is consistent and safe.
738 OrderAccess::cross_modify_fence();
739
740 assert(JavaThread::current() == this, "sanity check");
741 assert(!Thread::current()->owns_locks(), "sanity check");
742
743 JFR_ONLY(Jfr::on_thread_start(this);)
744
745 DTRACE_THREAD_PROBE(start, this);
746
747 // This operation might block. We call that after all safepoint checks for a new thread has
748 // been completed.
749 set_active_handles(JNIHandleBlock::allocate_block());
750
751 if (JvmtiExport::should_post_thread_life()) {
752 JvmtiExport::post_thread_start(this);
753
754 }
755
756 if (AlwaysPreTouchStacks) {
757 pretouch_stack();
758 }
759
760 // We call another function to do the rest so we are sure that the stack addresses used
761 // from there will be lower than the stack base just computed.
762 thread_main_inner();
763 }
764
765 void JavaThread::thread_main_inner() {
766 assert(JavaThread::current() == this, "sanity check");
767 assert(_threadObj.peek() != nullptr, "just checking");
768
769 // Execute thread entry point unless this thread has a pending exception.
770 // Note: Due to JVMTI StopThread we can have pending exceptions already!
771 if (!this->has_pending_exception()) {
772 {
773 ResourceMark rm(this);
774 this->set_native_thread_name(this->name());
775 }
776 HandleMark hm(this);
777 this->entry_point()(this, this);
778 }
779
780 DTRACE_THREAD_PROBE(stop, this);
781
782 // Cleanup is handled in post_run()
783 }
784
785 // Shared teardown for all JavaThreads
786 void JavaThread::post_run() {
787 this->exit(false);
788 this->unregister_thread_stack_with_NMT();
789 // Defer deletion to here to ensure 'this' is still referenceable in call_run
790 // for any shared tear-down.
791 this->smr_delete();
792 }
793
794 static void ensure_join(JavaThread* thread) {
795 // We do not need to grab the Threads_lock, since we are operating on ourself.
796 Handle threadObj(thread, thread->threadObj());
797 assert(threadObj.not_null(), "java thread object must exist");
798 ObjectLocker lock(threadObj, thread);
799 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
800 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
801 // Clear the native thread instance - this makes isAlive return false and allows the join()
802 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
803 // requirements.
804 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
805 java_lang_Thread::release_set_thread(threadObj(), nullptr);
806 lock.notify_all(thread);
807 // Ignore pending exception, since we are exiting anyway
808 thread->clear_pending_exception();
809 }
810
811 static bool is_daemon(oop threadObj) {
812 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
813 }
814
815 // For any new cleanup additions, please check to see if they need to be applied to
816 // cleanup_failed_attach_current_thread as well.
817 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
818 assert(this == JavaThread::current(), "thread consistency check");
819 assert(!is_exiting(), "should not be exiting or terminated already");
820
821 elapsedTimer _timer_exit_phase1;
822 elapsedTimer _timer_exit_phase2;
823 elapsedTimer _timer_exit_phase3;
824 elapsedTimer _timer_exit_phase4;
825
826 om_clear_monitor_cache();
827
828 if (log_is_enabled(Debug, os, thread, timer)) {
829 _timer_exit_phase1.start();
830 }
831
832 HandleMark hm(this);
833 Handle uncaught_exception(this, this->pending_exception());
834 this->clear_pending_exception();
835 Handle threadObj(this, this->threadObj());
836 assert(threadObj.not_null(), "Java thread object should be created");
837
838 if (!destroy_vm) {
839 if (uncaught_exception.not_null()) {
840 EXCEPTION_MARK;
841 // Call method Thread.dispatchUncaughtException().
842 Klass* thread_klass = vmClasses::Thread_klass();
843 JavaValue result(T_VOID);
844 JavaCalls::call_virtual(&result,
845 threadObj, thread_klass,
846 vmSymbols::dispatchUncaughtException_name(),
847 vmSymbols::throwable_void_signature(),
848 uncaught_exception,
849 THREAD);
850 if (HAS_PENDING_EXCEPTION) {
851 ResourceMark rm(this);
852 jio_fprintf(defaultStream::error_stream(),
853 "\nException: %s thrown from the UncaughtExceptionHandler"
854 " in thread \"%s\"\n",
855 pending_exception()->klass()->external_name(),
856 name());
857 CLEAR_PENDING_EXCEPTION;
858 }
859 }
860
861 if (!is_Compiler_thread()) {
862 // We have finished executing user-defined Java code and now have to do the
863 // implementation specific clean-up by calling Thread.exit(). We prevent any
864 // asynchronous exceptions from being delivered while in Thread.exit()
865 // to ensure the clean-up is not corrupted.
866 NoAsyncExceptionDeliveryMark _no_async(this);
867
868 EXCEPTION_MARK;
869 JavaValue result(T_VOID);
870 Klass* thread_klass = vmClasses::Thread_klass();
871 JavaCalls::call_virtual(&result,
872 threadObj, thread_klass,
873 vmSymbols::exit_method_name(),
874 vmSymbols::void_method_signature(),
875 THREAD);
876 CLEAR_PENDING_EXCEPTION;
877 }
878
879 // notify JVMTI
880 if (JvmtiExport::should_post_thread_life()) {
881 JvmtiExport::post_thread_end(this);
882 }
883 } else {
884 // before_exit() has already posted JVMTI THREAD_END events
885 }
886
887 // Cleanup any pending async exception now since we cannot access oops after
888 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
889 if (has_async_exception_condition()) {
890 handshake_state()->clean_async_exception_operation();
891 }
892
893 // The careful dance between thread suspension and exit is handled here.
894 // Since we are in thread_in_vm state and suspension is done with handshakes,
895 // we can just put in the exiting state and it will be correctly handled.
896 // Also, no more async exceptions will be added to the queue after this point.
897 set_terminated(_thread_exiting);
898 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
899
900 if (log_is_enabled(Debug, os, thread, timer)) {
901 _timer_exit_phase1.stop();
902 _timer_exit_phase2.start();
903 }
904
905 // Capture daemon status before the thread is marked as terminated.
906 bool daemon = is_daemon(threadObj());
907
908 // Notify waiters on thread object. This has to be done after exit() is called
909 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
910 // group should have the destroyed bit set before waiters are notified).
911 ensure_join(this);
912 assert(!this->has_pending_exception(), "ensure_join should have cleared");
913
914 if (log_is_enabled(Debug, os, thread, timer)) {
915 _timer_exit_phase2.stop();
916 _timer_exit_phase3.start();
917 }
918 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
919 // held by this thread must be released. The spec does not distinguish
920 // between JNI-acquired and regular Java monitors. We can only see
921 // regular Java monitors here if monitor enter-exit matching is broken.
922 //
923 // ensure_join() ignores IllegalThreadStateExceptions, and so does
924 // ObjectSynchronizer::release_monitors_owned_by_thread().
925 if (exit_type == jni_detach) {
926 // Sanity check even though JNI DetachCurrentThread() would have
927 // returned JNI_ERR if there was a Java frame. JavaThread exit
928 // should be done executing Java code by the time we get here.
929 assert(!this->has_last_Java_frame(),
930 "should not have a Java frame when detaching or exiting");
931 ObjectSynchronizer::release_monitors_owned_by_thread(this);
932 assert(!this->has_pending_exception(), "release_monitors should have cleared");
933 // Check for monitor counts being out of sync.
934 assert(held_monitor_count() == jni_monitor_count(),
935 "held monitor count should be equal to jni: %zd != %zd",
936 held_monitor_count(), jni_monitor_count());
937 // All in-use monitors, including JNI-locked ones, should have been released above.
938 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
939 held_monitor_count());
940 } else {
941 // Check for monitor counts being out of sync.
942 assert(held_monitor_count() == jni_monitor_count(),
943 "held monitor count should be equal to jni: %zd != %zd",
944 held_monitor_count(), jni_monitor_count());
945 // It is possible that a terminating thread failed to unlock monitors it locked
946 // via JNI so we don't assert the count is zero.
947 }
948
949 if (CheckJNICalls && jni_monitor_count() > 0) {
950 // We would like a fatal here, but due to we never checked this before there
951 // is a lot of tests which breaks, even with an error log.
952 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
953 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
954 }
955
956 // These things needs to be done while we are still a Java Thread. Make sure that thread
957 // is in a consistent state, in case GC happens
958 JFR_ONLY(Jfr::on_thread_exit(this);)
959
960 if (active_handles() != nullptr) {
961 JNIHandleBlock* block = active_handles();
962 set_active_handles(nullptr);
963 JNIHandleBlock::release_block(block);
964 }
965
966 if (free_handle_block() != nullptr) {
967 JNIHandleBlock* block = free_handle_block();
968 set_free_handle_block(nullptr);
969 JNIHandleBlock::release_block(block);
970 }
971
972 // These have to be removed while this is still a valid thread.
973 _stack_overflow_state.remove_stack_guard_pages();
974
975 if (UseTLAB) {
976 retire_tlab();
977 }
978
979 if (JvmtiEnv::environments_might_exist()) {
980 JvmtiExport::cleanup_thread(this);
981 }
982
983 // We need to cache the thread name for logging purposes below as once
984 // we have called on_thread_detach this thread must not access any oops.
985 char* thread_name = nullptr;
986 if (log_is_enabled(Debug, os, thread, timer)) {
987 ResourceMark rm(this);
988 thread_name = os::strdup(name());
989 }
990
991 if (log_is_enabled(Info, os, thread)) {
992 ResourceMark rm(this);
993 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
994 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
995 name(), os::current_thread_id());
996 }
997
998 if (log_is_enabled(Debug, os, thread, timer)) {
999 _timer_exit_phase3.stop();
1000 _timer_exit_phase4.start();
1001 }
1002
1003 #if INCLUDE_JVMCI
1004 if (JVMCICounterSize > 0) {
1005 if (jvmci_counters_include(this)) {
1006 for (int i = 0; i < JVMCICounterSize; i++) {
1007 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1008 }
1009 }
1010 }
1011 #endif // INCLUDE_JVMCI
1012
1013 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1014 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1015 Threads::remove(this, daemon);
1016
1017 if (log_is_enabled(Debug, os, thread, timer)) {
1018 _timer_exit_phase4.stop();
1019 log_debug(os, thread, timer)("name='%s'"
1020 ", exit-phase1=" JLONG_FORMAT
1021 ", exit-phase2=" JLONG_FORMAT
1022 ", exit-phase3=" JLONG_FORMAT
1023 ", exit-phase4=" JLONG_FORMAT,
1024 thread_name,
1025 _timer_exit_phase1.milliseconds(),
1026 _timer_exit_phase2.milliseconds(),
1027 _timer_exit_phase3.milliseconds(),
1028 _timer_exit_phase4.milliseconds());
1029 os::free(thread_name);
1030 }
1031 }
1032
1033 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1034 if (active_handles() != nullptr) {
1035 JNIHandleBlock* block = active_handles();
1036 set_active_handles(nullptr);
1037 JNIHandleBlock::release_block(block);
1038 }
1039
1040 if (free_handle_block() != nullptr) {
1041 JNIHandleBlock* block = free_handle_block();
1042 set_free_handle_block(nullptr);
1043 JNIHandleBlock::release_block(block);
1044 }
1045
1046 // These have to be removed while this is still a valid thread.
1047 _stack_overflow_state.remove_stack_guard_pages();
1048
1049 if (UseTLAB) {
1050 retire_tlab();
1051 }
1052
1053 Threads::remove(this, is_daemon);
1054 }
1055
1056 JavaThread* JavaThread::active() {
1057 Thread* thread = Thread::current();
1058 if (thread->is_Java_thread()) {
1059 return JavaThread::cast(thread);
1060 } else {
1061 assert(thread->is_VM_thread(), "this must be a vm thread");
1062 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1063 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1064 return ret;
1065 }
1066 }
1067
1068 oop JavaThread::exception_oop() const {
1069 return AtomicAccess::load(&_exception_oop);
1070 }
1071
1072 void JavaThread::set_exception_oop(oop o) {
1073 AtomicAccess::store(&_exception_oop, o);
1074 }
1075
1076 void JavaThread::handle_special_runtime_exit_condition() {
1077 if (is_obj_deopt_suspend()) {
1078 frame_anchor()->make_walkable();
1079 wait_for_object_deoptimization();
1080 }
1081 }
1082
1083
1084 // Asynchronous exceptions support
1085 //
1086 void JavaThread::handle_async_exception(oop java_throwable) {
1087 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1088 assert(!is_at_poll_safepoint(), "should have never called this method");
1089
1090 if (has_last_Java_frame()) {
1091 frame f = last_frame();
1092 if (f.is_runtime_frame()) {
1093 // If the topmost frame is a runtime stub, then we are calling into
1094 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1095 // must deoptimize the caller before continuing, as the compiled exception
1096 // handler table may not be valid.
1097 RegisterMap reg_map(this,
1098 RegisterMap::UpdateMap::skip,
1099 RegisterMap::ProcessFrames::include,
1100 RegisterMap::WalkContinuation::skip);
1101 frame compiled_frame = f.sender(®_map);
1102 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1103 Deoptimization::deoptimize(this, compiled_frame);
1104 }
1105 }
1106 }
1107
1108 // We cannot call Exceptions::_throw(...) here because we cannot block
1109 set_pending_exception(java_throwable, __FILE__, __LINE__);
1110
1111 clear_scopedValueBindings();
1112
1113 LogTarget(Info, exceptions) lt;
1114 if (lt.is_enabled()) {
1115 ResourceMark rm;
1116 LogStream ls(lt);
1117 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1118 if (has_last_Java_frame()) {
1119 frame f = last_frame();
1120 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1121 }
1122 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1123 }
1124 }
1125
1126 void JavaThread::install_async_exception(AsyncExceptionHandshakeClosure* aehc) {
1127 // Do not throw asynchronous exceptions against the compiler thread
1128 // or if the thread is already exiting.
1129 if (!can_call_java() || is_exiting()) {
1130 delete aehc;
1131 return;
1132 }
1133
1134 oop exception = aehc->exception();
1135 Handshake::execute(aehc, this); // Install asynchronous handshake
1136
1137 ResourceMark rm;
1138 if (log_is_enabled(Info, exceptions)) {
1139 log_info(exceptions)("Pending Async. exception installed of type: %s",
1140 exception->klass()->external_name());
1141 }
1142 // for AbortVMOnException flag
1143 Exceptions::debug_check_abort(exception->klass()->external_name());
1144
1145 oop vt_oop = vthread();
1146 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1147 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1148 this->interrupt();
1149 }
1150 }
1151
1152 class InstallAsyncExceptionHandshakeClosure : public HandshakeClosure {
1153 AsyncExceptionHandshakeClosure* _aehc;
1154 public:
1155 InstallAsyncExceptionHandshakeClosure(AsyncExceptionHandshakeClosure* aehc) :
1156 HandshakeClosure("InstallAsyncException"), _aehc(aehc) {}
1157 ~InstallAsyncExceptionHandshakeClosure() {
1158 // If InstallAsyncExceptionHandshakeClosure was never executed we need to clean up _aehc.
1159 delete _aehc;
1160 }
1161 void do_thread(Thread* thr) {
1162 JavaThread* target = JavaThread::cast(thr);
1163 target->install_async_exception(_aehc);
1164 _aehc = nullptr;
1165 }
1166 };
1167
1168 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1169 OopHandle e(Universe::vm_global(), java_throwable);
1170 InstallAsyncExceptionHandshakeClosure iaeh(new AsyncExceptionHandshakeClosure(e));
1171 Handshake::execute(&iaeh, target);
1172 }
1173
1174 #if INCLUDE_JVMTI
1175 void JavaThread::set_is_in_VTMS_transition(bool val) {
1176 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1177 _is_in_VTMS_transition = val;
1178 }
1179
1180 #ifdef ASSERT
1181 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1182 _is_VTMS_transition_disabler = val;
1183 }
1184 #endif
1185 #endif
1186
1187 // External suspension mechanism.
1188 //
1189 // Guarantees on return (for a valid target thread):
1190 // - Target thread will not execute any new bytecode.
1191 // - Target thread will not enter any new monitors.
1192 //
1193 bool JavaThread::java_suspend(bool register_vthread_SR) {
1194 #if INCLUDE_JVMTI
1195 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1196 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1197 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1198 #endif
1199
1200 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1201 "target JavaThread is not protected in calling context.");
1202 return this->suspend_resume_manager()->suspend(register_vthread_SR);
1203 }
1204
1205 bool JavaThread::java_resume(bool register_vthread_SR) {
1206 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1207 "missing ThreadsListHandle in calling context.");
1208 return this->suspend_resume_manager()->resume(register_vthread_SR);
1209 }
1210
1211 // Wait for another thread to perform object reallocation and relocking on behalf of
1212 // this thread. The current thread is required to change to _thread_blocked in order
1213 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1214 // handshake safe, the other thread can complete the handshake used to synchronize
1215 // with this thread and then perform the reallocation and relocking.
1216 // See EscapeBarrier::sync_and_suspend_*()
1217
1218 void JavaThread::wait_for_object_deoptimization() {
1219 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1220 assert(this == Thread::current(), "invariant");
1221
1222 bool spin_wait = os::is_MP();
1223 do {
1224 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1225 // Wait for object deoptimization if requested.
1226 if (spin_wait) {
1227 // A single deoptimization is typically very short. Microbenchmarks
1228 // showed 5% better performance when spinning.
1229 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1230 SpinYield spin(spin_limit);
1231 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1232 spin.wait();
1233 }
1234 // Spin just once
1235 spin_wait = false;
1236 } else {
1237 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1238 if (is_obj_deopt_suspend()) {
1239 ml.wait();
1240 }
1241 }
1242 // A handshake for obj. deoptimization suspend could have been processed so
1243 // we must check after processing.
1244 } while (is_obj_deopt_suspend());
1245 }
1246
1247 #ifdef ASSERT
1248 // Verify the JavaThread has not yet been published in the Threads::list, and
1249 // hence doesn't need protection from concurrent access at this stage.
1250 void JavaThread::verify_not_published() {
1251 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1252 // since an unpublished JavaThread doesn't participate in the
1253 // Thread-SMR protocol for keeping a ThreadsList alive.
1254 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1255 }
1256 #endif
1257
1258 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1259 // pending, when _suspend_flags is non-zero or when we need to process a stack
1260 // watermark. Also check for pending async exceptions (except unsafe access error).
1261 // Note only the native==>Java barriers can call this function when thread state
1262 // is _thread_in_native_trans.
1263 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1264 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1265 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1266
1267 thread->set_thread_state(_thread_in_vm);
1268
1269 // Enable WXWrite: called directly from interpreter native wrapper.
1270 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1271
1272 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1273
1274 // After returning from native, it could be that the stack frames are not
1275 // yet safe to use. We catch such situations in the subsequent stack watermark
1276 // barrier, which will trap unsafe stack frames.
1277 StackWatermarkSet::before_unwind(thread);
1278 }
1279
1280 #ifndef PRODUCT
1281 // Deoptimization
1282 // Function for testing deoptimization
1283 void JavaThread::deoptimize() {
1284 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1285 bool deopt = false; // Dump stack only if a deopt actually happens.
1286 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1287 // Iterate over all frames in the thread and deoptimize
1288 for (; !fst.is_done(); fst.next()) {
1289 if (fst.current()->can_be_deoptimized()) {
1290
1291 if (only_at) {
1292 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1293 // consists of comma or carriage return separated numbers so
1294 // search for the current bci in that string.
1295 address pc = fst.current()->pc();
1296 nmethod* nm = fst.current()->cb()->as_nmethod();
1297 ScopeDesc* sd = nm->scope_desc_at(pc);
1298 char buffer[8];
1299 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1300 size_t len = strlen(buffer);
1301 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1302 while (found != nullptr) {
1303 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1304 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1305 // Check that the bci found is bracketed by terminators.
1306 break;
1307 }
1308 found = strstr(found + 1, buffer);
1309 }
1310 if (!found) {
1311 continue;
1312 }
1313 }
1314
1315 if (DebugDeoptimization && !deopt) {
1316 deopt = true; // One-time only print before deopt
1317 tty->print_cr("[BEFORE Deoptimization]");
1318 trace_frames();
1319 trace_stack();
1320 }
1321 Deoptimization::deoptimize(this, *fst.current());
1322 }
1323 }
1324
1325 if (DebugDeoptimization && deopt) {
1326 tty->print_cr("[AFTER Deoptimization]");
1327 trace_frames();
1328 }
1329 }
1330
1331
1332 // Make zombies
1333 void JavaThread::make_zombies() {
1334 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1335 if (fst.current()->can_be_deoptimized()) {
1336 // it is a Java nmethod
1337 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1338 assert(nm != nullptr, "did not find nmethod");
1339 nm->make_not_entrant(nmethod::InvalidationReason::ZOMBIE);
1340 }
1341 }
1342 }
1343 #endif // PRODUCT
1344
1345
1346 void JavaThread::deoptimize_marked_methods() {
1347 if (!has_last_Java_frame()) return;
1348 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1349 for (; !fst.is_done(); fst.next()) {
1350 if (fst.current()->should_be_deoptimized()) {
1351 Deoptimization::deoptimize(this, *fst.current());
1352 }
1353 }
1354 }
1355
1356 #ifdef ASSERT
1357 void JavaThread::verify_frame_info() {
1358 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1359 (has_last_Java_frame() && java_call_counter() > 0),
1360 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1361 has_last_Java_frame() ? "true" : "false", java_call_counter());
1362 }
1363 #endif
1364
1365 // Push on a new block of JNI handles.
1366 void JavaThread::push_jni_handle_block() {
1367 // Allocate a new block for JNI handles.
1368 // Inlined code from jni_PushLocalFrame()
1369 JNIHandleBlock* old_handles = active_handles();
1370 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1371 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1372 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1373 set_active_handles(new_handles);
1374 }
1375
1376 // Pop off the current block of JNI handles.
1377 void JavaThread::pop_jni_handle_block() {
1378 // Release our JNI handle block
1379 JNIHandleBlock* old_handles = active_handles();
1380 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1381 assert(new_handles != nullptr, "should never set active handles to null");
1382 set_active_handles(new_handles);
1383 old_handles->set_pop_frame_link(nullptr);
1384 JNIHandleBlock::release_block(old_handles, this);
1385 }
1386
1387 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1388 // Verify that the deferred card marks have been flushed.
1389 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1390
1391 // Traverse the GCHandles
1392 Thread::oops_do_no_frames(f, cf);
1393
1394 if (active_handles() != nullptr) {
1395 active_handles()->oops_do(f);
1396 }
1397
1398 DEBUG_ONLY(verify_frame_info();)
1399
1400 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1401 // If we have deferred set_locals there might be oops waiting to be
1402 // written
1403 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1404 if (list != nullptr) {
1405 for (int i = 0; i < list->length(); i++) {
1406 list->at(i)->oops_do(f);
1407 }
1408 }
1409
1410 // Traverse instance variables at the end since the GC may be moving things
1411 // around using this function
1412 f->do_oop((oop*) &_vm_result_oop);
1413 f->do_oop((oop*) &_exception_oop);
1414 #if INCLUDE_JVMCI
1415 f->do_oop((oop*) &_jvmci_reserved_oop0);
1416
1417 if (_live_nmethod != nullptr && cf != nullptr) {
1418 cf->do_nmethod(_live_nmethod);
1419 }
1420 #endif
1421
1422 if (jvmti_thread_state() != nullptr) {
1423 jvmti_thread_state()->oops_do(f, cf);
1424 }
1425
1426 // The continuation oops are really on the stack. But there is typically at most
1427 // one of those per thread, so we handle them here in the oops_do_no_frames part
1428 // so that we don't have to sprinkle as many stack watermark checks where these
1429 // oops are used. We just need to make sure the thread has started processing.
1430 ContinuationEntry* entry = _cont_entry;
1431 while (entry != nullptr) {
1432 f->do_oop((oop*)entry->cont_addr());
1433 f->do_oop((oop*)entry->chunk_addr());
1434 entry = entry->parent();
1435 }
1436
1437 // Due to lightweight locking
1438 lock_stack().oops_do(f);
1439 }
1440
1441 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1442 if (!has_last_Java_frame()) {
1443 return;
1444 }
1445 // Finish any pending lazy GC activity for the frames
1446 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1447 // Traverse the execution stack
1448 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1449 fst.current()->oops_do(f, cf, fst.register_map());
1450 }
1451 }
1452
1453 #ifdef ASSERT
1454 void JavaThread::verify_states_for_handshake() {
1455 // This checks that the thread has a correct frame state during a handshake.
1456 verify_frame_info();
1457 }
1458 #endif
1459
1460 void JavaThread::nmethods_do(NMethodClosure* cf) {
1461 DEBUG_ONLY(verify_frame_info();)
1462 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1463
1464 if (has_last_Java_frame()) {
1465 // Traverse the execution stack
1466 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1467 fst.current()->nmethod_do(cf);
1468 }
1469 }
1470
1471 if (jvmti_thread_state() != nullptr) {
1472 jvmti_thread_state()->nmethods_do(cf);
1473 }
1474
1475 #if INCLUDE_JVMCI
1476 if (_live_nmethod != nullptr) {
1477 cf->do_nmethod(_live_nmethod);
1478 }
1479 #endif
1480 }
1481
1482 void JavaThread::metadata_do(MetadataClosure* f) {
1483 if (has_last_Java_frame()) {
1484 // Traverse the execution stack to call f() on the methods in the stack
1485 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1486 fst.current()->metadata_do(f);
1487 }
1488 } else if (is_Compiler_thread()) {
1489 // need to walk ciMetadata in current compile tasks to keep alive.
1490 CompilerThread* ct = (CompilerThread*)this;
1491 if (ct->env() != nullptr) {
1492 ct->env()->metadata_do(f);
1493 }
1494 CompileTask* task = ct->task();
1495 if (task != nullptr) {
1496 task->metadata_do(f);
1497 }
1498 }
1499 }
1500
1501 // Printing
1502 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1503 switch (_thread_state) {
1504 case _thread_uninitialized: return "_thread_uninitialized";
1505 case _thread_new: return "_thread_new";
1506 case _thread_new_trans: return "_thread_new_trans";
1507 case _thread_in_native: return "_thread_in_native";
1508 case _thread_in_native_trans: return "_thread_in_native_trans";
1509 case _thread_in_vm: return "_thread_in_vm";
1510 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1511 case _thread_in_Java: return "_thread_in_Java";
1512 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1513 case _thread_blocked: return "_thread_blocked";
1514 case _thread_blocked_trans: return "_thread_blocked_trans";
1515 default: return "unknown thread state";
1516 }
1517 }
1518
1519 void JavaThread::print_thread_state_on(outputStream *st) const {
1520 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1521 }
1522
1523 // Called by Threads::print() for VM_PrintThreads operation
1524 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1525 st->print_raw("\"");
1526 st->print_raw(name());
1527 st->print_raw("\" ");
1528 oop thread_oop = threadObj();
1529 if (thread_oop != nullptr) {
1530 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1531 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1532 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1533 }
1534 Thread::print_on(st, print_extended_info);
1535 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1536 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1537 if (thread_oop != nullptr) {
1538 if (is_vthread_mounted()) {
1539 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1540 } else {
1541 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1542 }
1543 }
1544 #ifndef PRODUCT
1545 _safepoint_state->print_on(st);
1546 #endif // PRODUCT
1547 if (is_Compiler_thread()) {
1548 CompileTask *task = ((CompilerThread*)this)->task();
1549 if (task != nullptr) {
1550 st->print(" Compiling: ");
1551 task->print(st, nullptr, true, false);
1552 } else {
1553 st->print(" No compile task");
1554 }
1555 st->cr();
1556 }
1557 }
1558
1559 void JavaThread::print() const { print_on(tty); }
1560
1561 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1562 st->print("%s", get_thread_name_string(buf, buflen));
1563 }
1564
1565 // Called by fatal error handler. The difference between this and
1566 // JavaThread::print() is that we can't grab lock or allocate memory.
1567 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1568 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1569 Thread* current = Thread::current_or_null_safe();
1570 assert(current != nullptr, "cannot be called by a detached thread");
1571 st->fill_to(60);
1572 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1573 // Only access threadObj() if current thread is not a JavaThread
1574 // or if it is a JavaThread that can safely access oops.
1575 oop thread_obj = threadObj();
1576 if (thread_obj != nullptr) {
1577 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1578 }
1579 }
1580 st->print(" [");
1581 st->print("%s", _get_thread_state_name(_thread_state));
1582 if (osthread()) {
1583 st->print(", id=%d", osthread()->thread_id());
1584 }
1585 // Use raw field members for stack base/size as this could be
1586 // called before a thread has run enough to initialize them.
1587 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1588 p2i(_stack_base - _stack_size), p2i(_stack_base),
1589 PROPERFMTARGS(_stack_size));
1590 st->print("]");
1591
1592 ThreadsSMRSupport::print_info_on(this, st);
1593 return;
1594 }
1595
1596
1597 // Verification
1598
1599 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1600 // ignore if there is no stack
1601 if (!has_last_Java_frame()) return;
1602 // traverse the stack frames. Starts from top frame.
1603 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1604 frame* fr = fst.current();
1605 f(fr, fst.register_map());
1606 }
1607 }
1608
1609 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1610
1611 void JavaThread::verify() {
1612 // Verify oops in the thread.
1613 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1614
1615 // Verify the stack frames.
1616 frames_do(frame_verify);
1617 }
1618
1619 // CR 6300358 (sub-CR 2137150)
1620 // Most callers of this method assume that it can't return null but a
1621 // thread may not have a name whilst it is in the process of attaching to
1622 // the VM - see CR 6412693, and there are places where a JavaThread can be
1623 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1624 // if vm exit occurs during initialization). These cases can all be accounted
1625 // for such that this method never returns null.
1626 const char* JavaThread::name() const {
1627 if (Thread::is_JavaThread_protected(/* target */ this)) {
1628 // The target JavaThread is protected so get_thread_name_string() is safe:
1629 return get_thread_name_string();
1630 }
1631
1632 // The target JavaThread is not protected so we return the default:
1633 return Thread::name();
1634 }
1635
1636 // Like name() but doesn't include the protection check. This must only be
1637 // called when it is known to be safe, even though the protection check can't tell
1638 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1639 const char* JavaThread::name_raw() const {
1640 return get_thread_name_string();
1641 }
1642
1643 // Returns a non-null representation of this thread's name, or a suitable
1644 // descriptive string if there is no set name.
1645 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1646 const char* name_str;
1647 #ifdef ASSERT
1648 Thread* current = Thread::current_or_null_safe();
1649 assert(current != nullptr, "cannot be called by a detached thread");
1650 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1651 // Only access threadObj() if current thread is not a JavaThread
1652 // or if it is a JavaThread that can safely access oops.
1653 #endif
1654 oop thread_obj = threadObj();
1655 if (thread_obj != nullptr) {
1656 oop name = java_lang_Thread::name(thread_obj);
1657 if (name != nullptr) {
1658 if (buf == nullptr) {
1659 name_str = java_lang_String::as_utf8_string(name);
1660 } else {
1661 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1662 }
1663 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1664 name_str = "<no-name - thread is attaching>";
1665 } else {
1666 name_str = "<un-named>";
1667 }
1668 } else {
1669 name_str = Thread::name();
1670 }
1671 #ifdef ASSERT
1672 } else {
1673 // Current JavaThread has exited...
1674 if (current == this) {
1675 // ... and is asking about itself:
1676 name_str = "<no-name - current JavaThread has exited>";
1677 } else {
1678 // ... and it can't safely determine this JavaThread's name so
1679 // use the default thread name.
1680 name_str = Thread::name();
1681 }
1682 }
1683 #endif
1684 assert(name_str != nullptr, "unexpected null thread name");
1685 return name_str;
1686 }
1687
1688 // Helper to extract the name from the thread oop for logging.
1689 const char* JavaThread::name_for(oop thread_obj) {
1690 assert(thread_obj != nullptr, "precondition");
1691 oop name = java_lang_Thread::name(thread_obj);
1692 const char* name_str;
1693 if (name != nullptr) {
1694 name_str = java_lang_String::as_utf8_string(name);
1695 } else {
1696 name_str = "<un-named>";
1697 }
1698 return name_str;
1699 }
1700
1701 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1702
1703 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1704 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1705 // Link Java Thread object <-> C++ Thread
1706
1707 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1708 // and put it into a new Handle. The Handle "thread_oop" can then
1709 // be used to pass the C++ thread object to other methods.
1710
1711 // Set the Java level thread object (jthread) field of the
1712 // new thread (a JavaThread *) to C++ thread object using the
1713 // "thread_oop" handle.
1714
1715 // Set the thread field (a JavaThread *) of the
1716 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1717
1718 Handle thread_oop(Thread::current(),
1719 JNIHandles::resolve_non_null(jni_thread));
1720 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1721 "must be initialized");
1722 set_threadOopHandles(thread_oop());
1723 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1724
1725 if (prio == NoPriority) {
1726 prio = java_lang_Thread::priority(thread_oop());
1727 assert(prio != NoPriority, "A valid priority should be present");
1728 }
1729
1730 // Push the Java priority down to the native thread; needs Threads_lock
1731 Thread::set_priority(this, prio);
1732
1733 // Add the new thread to the Threads list and set it in motion.
1734 // We must have threads lock in order to call Threads::add.
1735 // It is crucial that we do not block before the thread is
1736 // added to the Threads list for if a GC happens, then the java_thread oop
1737 // will not be visited by GC.
1738 Threads::add(this);
1739 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1740 // on a ThreadsList. We don't want to wait for the release when the
1741 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1742 // is already visible to JVM/TI via the ThreadsList.
1743 java_lang_Thread::release_set_thread(thread_oop(), this);
1744 }
1745
1746 oop JavaThread::current_park_blocker() {
1747 // Support for JSR-166 locks
1748 oop thread_oop = threadObj();
1749 if (thread_oop != nullptr) {
1750 return java_lang_Thread::park_blocker(thread_oop);
1751 }
1752 return nullptr;
1753 }
1754
1755 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1756 // This is the external format, selecting the platform or vthread
1757 // as applicable, and allowing for a native-only stack.
1758 void JavaThread::print_jni_stack() {
1759 assert(this == JavaThread::current(), "Can't print stack of other threads");
1760 if (!has_last_Java_frame()) {
1761 ResourceMark rm(this);
1762 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1763 if (buf == nullptr) {
1764 tty->print_cr("Unable to print native stack - out of memory");
1765 return;
1766 }
1767 NativeStackPrinter nsp(this);
1768 address lastpc = nullptr;
1769 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1770 true /*print_source_info */, -1 /* max stack */ );
1771 } else {
1772 print_active_stack_on(tty);
1773 }
1774 }
1775
1776 void JavaThread::print_stack_on(outputStream* st) {
1777 if (!has_last_Java_frame()) return;
1778
1779 Thread* current_thread = Thread::current();
1780 ResourceMark rm(current_thread);
1781 HandleMark hm(current_thread);
1782
1783 RegisterMap reg_map(this,
1784 RegisterMap::UpdateMap::include,
1785 RegisterMap::ProcessFrames::include,
1786 RegisterMap::WalkContinuation::skip);
1787 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1788 int count = 0;
1789 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1790 if (f->is_java_frame()) {
1791 javaVFrame* jvf = javaVFrame::cast(f);
1792 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1793
1794 // Print out lock information
1795 if (JavaMonitorsInStackTrace) {
1796 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1797 }
1798 } else {
1799 // Ignore non-Java frames
1800 }
1801
1802 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1803 count++;
1804 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1805 }
1806 }
1807
1808 void JavaThread::print_vthread_stack_on(outputStream* st) {
1809 assert(is_vthread_mounted(), "Caller should have checked this");
1810 assert(has_last_Java_frame(), "must be");
1811
1812 Thread* current_thread = Thread::current();
1813 ResourceMark rm(current_thread);
1814 HandleMark hm(current_thread);
1815
1816 RegisterMap reg_map(this,
1817 RegisterMap::UpdateMap::include,
1818 RegisterMap::ProcessFrames::include,
1819 RegisterMap::WalkContinuation::include);
1820 ContinuationEntry* cont_entry = last_continuation();
1821 vframe* start_vf = last_java_vframe(®_map);
1822 int count = 0;
1823 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1824 // Watch for end of vthread stack
1825 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1826 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1827 if (cont_entry->is_virtual_thread()) {
1828 break;
1829 }
1830 cont_entry = cont_entry->parent();
1831 }
1832 if (f->is_java_frame()) {
1833 javaVFrame* jvf = javaVFrame::cast(f);
1834 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1835
1836 // Print out lock information
1837 if (JavaMonitorsInStackTrace) {
1838 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1839 }
1840 } else {
1841 // Ignore non-Java frames
1842 }
1843
1844 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1845 count++;
1846 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1847 }
1848 }
1849
1850 void JavaThread::print_active_stack_on(outputStream* st) {
1851 if (is_vthread_mounted()) {
1852 print_vthread_stack_on(st);
1853 } else {
1854 print_stack_on(st);
1855 }
1856 }
1857
1858 #if INCLUDE_JVMTI
1859 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1860 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1861 set_jvmti_vthread(thread_oop);
1862
1863 // unbind current JvmtiThreadState from JavaThread
1864 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1865
1866 // bind new JvmtiThreadState to JavaThread
1867 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1868
1869 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1870 JvmtiThreadState::process_pending_interp_only(this);
1871
1872 return jvmti_thread_state();
1873 }
1874 #endif
1875
1876 // JVMTI PopFrame support
1877 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1878 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1879 if (in_bytes(size_in_bytes) != 0) {
1880 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1881 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1882 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1883 }
1884 }
1885
1886 void* JavaThread::popframe_preserved_args() {
1887 return _popframe_preserved_args;
1888 }
1889
1890 ByteSize JavaThread::popframe_preserved_args_size() {
1891 return in_ByteSize(_popframe_preserved_args_size);
1892 }
1893
1894 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1895 int sz = in_bytes(popframe_preserved_args_size());
1896 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1897 return in_WordSize(sz / wordSize);
1898 }
1899
1900 void JavaThread::popframe_free_preserved_args() {
1901 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1902 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1903 _popframe_preserved_args = nullptr;
1904 _popframe_preserved_args_size = 0;
1905 }
1906
1907 #ifndef PRODUCT
1908
1909 void JavaThread::trace_frames() {
1910 tty->print_cr("[Describe stack]");
1911 int frame_no = 1;
1912 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1913 tty->print(" %d. ", frame_no++);
1914 fst.current()->print_value_on(tty);
1915 tty->cr();
1916 }
1917 }
1918
1919 class PrintAndVerifyOopClosure: public OopClosure {
1920 protected:
1921 template <class T> inline void do_oop_work(T* p) {
1922 oop obj = RawAccess<>::oop_load(p);
1923 if (obj == nullptr) return;
1924 tty->print(INTPTR_FORMAT ": ", p2i(p));
1925 if (oopDesc::is_oop_or_null(obj)) {
1926 if (obj->is_objArray()) {
1927 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1928 } else {
1929 obj->print();
1930 }
1931 } else {
1932 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1933 }
1934 tty->cr();
1935 }
1936 public:
1937 virtual void do_oop(oop* p) { do_oop_work(p); }
1938 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1939 };
1940
1941 #ifdef ASSERT
1942 // Print or validate the layout of stack frames
1943 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1944 ResourceMark rm;
1945 PreserveExceptionMark pm(this);
1946 FrameValues values;
1947 int frame_no = 0;
1948 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1949 fst.current()->describe(values, ++frame_no, fst.register_map());
1950 if (depth == frame_no) break;
1951 }
1952 Continuation::describe(values);
1953 if (validate_only) {
1954 values.validate();
1955 } else {
1956 tty->print_cr("[Describe stack layout]");
1957 values.print(this);
1958 }
1959 }
1960 #endif
1961
1962 void JavaThread::trace_stack_from(vframe* start_vf) {
1963 ResourceMark rm;
1964 int vframe_no = 1;
1965 for (vframe* f = start_vf; f; f = f->sender()) {
1966 if (f->is_java_frame()) {
1967 javaVFrame::cast(f)->print_activation(vframe_no++);
1968 } else {
1969 f->print();
1970 }
1971 if (vframe_no > StackPrintLimit) {
1972 tty->print_cr("...<more frames>...");
1973 return;
1974 }
1975 }
1976 }
1977
1978
1979 void JavaThread::trace_stack() {
1980 if (!has_last_Java_frame()) return;
1981 Thread* current_thread = Thread::current();
1982 ResourceMark rm(current_thread);
1983 HandleMark hm(current_thread);
1984 RegisterMap reg_map(this,
1985 RegisterMap::UpdateMap::include,
1986 RegisterMap::ProcessFrames::include,
1987 RegisterMap::WalkContinuation::skip);
1988 trace_stack_from(last_java_vframe(®_map));
1989 }
1990
1991
1992 #endif // PRODUCT
1993
1994 // Slow-path increment of the held monitor counts. JNI locking is always
1995 // this slow-path.
1996 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
1997 #ifdef SUPPORT_MONITOR_COUNT
1998 // Nothing to do. Just do some sanity check.
1999 assert(_held_monitor_count == 0, "counter should not be used");
2000 assert(_jni_monitor_count == 0, "counter should not be used");
2001 #endif // SUPPORT_MONITOR_COUNT
2002 }
2003
2004 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2005 // this slow-path.
2006 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2007 #ifdef SUPPORT_MONITOR_COUNT
2008 // Nothing to do. Just do some sanity check.
2009 assert(_held_monitor_count == 0, "counter should not be used");
2010 assert(_jni_monitor_count == 0, "counter should not be used");
2011 #endif // SUPPORT_MONITOR_COUNT
2012 }
2013
2014 frame JavaThread::vthread_last_frame() {
2015 assert (is_vthread_mounted(), "Virtual thread not mounted");
2016 return last_frame();
2017 }
2018
2019 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2020 const ContinuationEntry* entry = vthread_continuation();
2021 guarantee (entry != nullptr, "Not a carrier thread");
2022 frame f = entry->to_frame();
2023 if (reg_map->process_frames()) {
2024 entry->flush_stack_processing(this);
2025 }
2026 entry->update_register_map(reg_map);
2027 return f.sender(reg_map);
2028 }
2029
2030 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2031 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2032 }
2033
2034 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2035 assert(reg_map != nullptr, "a map must be given");
2036 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2037 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2038 }
2039 return nullptr;
2040 }
2041
2042 Klass* JavaThread::security_get_caller_class(int depth) {
2043 ResetNoHandleMark rnhm;
2044 HandleMark hm(Thread::current());
2045
2046 vframeStream vfst(this);
2047 vfst.security_get_caller_frame(depth);
2048 if (!vfst.at_end()) {
2049 return vfst.method()->method_holder();
2050 }
2051 return nullptr;
2052 }
2053
2054 // Internal convenience function for millisecond resolution sleeps.
2055 bool JavaThread::sleep(jlong millis) {
2056 jlong nanos;
2057 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2058 // Conversion to nanos would overflow, saturate at max
2059 nanos = max_jlong;
2060 } else {
2061 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2062 }
2063 return sleep_nanos(nanos);
2064 }
2065
2066 // java.lang.Thread.sleep support
2067 // Returns true if sleep time elapsed as expected, and false
2068 // if the thread was interrupted or async exception was installed.
2069 bool JavaThread::sleep_nanos(jlong nanos) {
2070 assert(this == Thread::current(), "thread consistency check");
2071 assert(nanos >= 0, "nanos are in range");
2072
2073 ParkEvent * const slp = this->_SleepEvent;
2074 // Because there can be races with thread interruption sending an unpark()
2075 // to the event, we explicitly reset it here to avoid an immediate return.
2076 // The actual interrupt state will be checked before we park().
2077 slp->reset();
2078 // Thread interruption establishes a happens-before ordering in the
2079 // Java Memory Model, so we need to ensure we synchronize with the
2080 // interrupt state.
2081 OrderAccess::fence();
2082
2083 jlong prevtime = os::javaTimeNanos();
2084
2085 jlong nanos_remaining = nanos;
2086
2087 for (;;) {
2088 if (has_async_exception_condition()) {
2089 return false;
2090 }
2091 // interruption has precedence over timing out
2092 if (this->is_interrupted(true)) {
2093 return false;
2094 }
2095
2096 if (nanos_remaining <= 0) {
2097 return true;
2098 }
2099
2100 {
2101 ThreadBlockInVM tbivm(this);
2102 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2103 slp->park_nanos(nanos_remaining);
2104 }
2105
2106 // Update elapsed time tracking
2107 jlong newtime = os::javaTimeNanos();
2108 if (newtime - prevtime < 0) {
2109 // time moving backwards, should only happen if no monotonic clock
2110 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2111 assert(false,
2112 "unexpected time moving backwards detected in JavaThread::sleep()");
2113 } else {
2114 nanos_remaining -= (newtime - prevtime);
2115 }
2116 prevtime = newtime;
2117 }
2118 }
2119
2120 // Last thread running calls java.lang.Shutdown.shutdown()
2121 void JavaThread::invoke_shutdown_hooks() {
2122 HandleMark hm(this);
2123
2124 // We could get here with a pending exception, if so clear it now.
2125 if (this->has_pending_exception()) {
2126 this->clear_pending_exception();
2127 }
2128
2129 EXCEPTION_MARK;
2130 Klass* shutdown_klass =
2131 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2132 THREAD);
2133 if (shutdown_klass != nullptr) {
2134 // SystemDictionary::resolve_or_null will return null if there was
2135 // an exception. If we cannot load the Shutdown class, just don't
2136 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2137 // won't be run. Note that if a shutdown hook was registered,
2138 // the Shutdown class would have already been loaded
2139 // (Runtime.addShutdownHook will load it).
2140 JavaValue result(T_VOID);
2141 JavaCalls::call_static(&result,
2142 shutdown_klass,
2143 vmSymbols::shutdown_name(),
2144 vmSymbols::void_method_signature(),
2145 THREAD);
2146 }
2147 CLEAR_PENDING_EXCEPTION;
2148 }
2149
2150 #ifndef PRODUCT
2151 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2152 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2153 }
2154 #endif
2155
2156 // Helper function to create the java.lang.Thread object for a
2157 // VM-internal thread. The thread will have the given name, and be
2158 // a member of the "system" ThreadGroup.
2159 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2160 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2161
2162 // Initialize thread_oop to put it into the system threadGroup.
2163 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2164 Handle thread_group(THREAD, Universe::system_thread_group());
2165 Handle thread_oop =
2166 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2167 vmSymbols::threadgroup_string_void_signature(),
2168 thread_group,
2169 string,
2170 CHECK_NH);
2171
2172 return thread_oop;
2173 }
2174
2175 // Starts the target JavaThread as a daemon of the given priority, and
2176 // bound to the given java.lang.Thread instance.
2177 // The Threads_lock is held for the duration.
2178 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2179 Handle thread_oop, ThreadPriority prio) {
2180
2181 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2182
2183 MutexLocker mu(current, Threads_lock);
2184
2185 // Initialize the fields of the thread_oop first.
2186 if (prio != NoPriority) {
2187 java_lang_Thread::set_priority(thread_oop(), prio);
2188 // Note: we don't call os::set_priority here. Possibly we should,
2189 // else all threads should call it themselves when they first run.
2190 }
2191
2192 java_lang_Thread::set_daemon(thread_oop());
2193
2194 // Now bind the thread_oop to the target JavaThread.
2195 target->set_threadOopHandles(thread_oop());
2196 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2197
2198 Threads::add(target); // target is now visible for safepoint/handshake
2199 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2200 // on a ThreadsList. We don't want to wait for the release when the
2201 // Theads_lock is dropped when the 'mu' destructor is run since the
2202 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2203
2204 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2205 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2206 Thread::start(target);
2207 }
2208
2209 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2210 // At this point it may be possible that no osthread was created for the
2211 // JavaThread due to lack of resources. However, since this must work
2212 // for critical system threads just check and abort if this fails.
2213 if (thread->osthread() == nullptr) {
2214 // This isn't really an OOM condition, but historically this is what
2215 // we report.
2216 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2217 os::native_thread_creation_failed_msg());
2218 }
2219 }
2220
2221 void JavaThread::pretouch_stack() {
2222 // Given an established java thread stack with usable area followed by
2223 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2224 // from the current frame down to the start of the shadow zone.
2225 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2226 if (is_in_full_stack(end)) {
2227 char* p1 = (char*) alloca(1);
2228 address here = (address) &p1;
2229 if (is_in_full_stack(here) && here > end) {
2230 size_t to_alloc = here - end;
2231 char* p2 = (char*) alloca(to_alloc);
2232 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2233 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2234 os::pretouch_memory(p2, p2 + to_alloc,
2235 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2236 }
2237 }
2238 }
2239
2240 // Deferred OopHandle release support.
2241
2242 class OopHandleList : public CHeapObj<mtInternal> {
2243 static const int _count = 4;
2244 OopHandle _handles[_count];
2245 OopHandleList* _next;
2246 int _index;
2247 public:
2248 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2249 void add(OopHandle h) {
2250 assert(_index < _count, "too many additions");
2251 _handles[_index++] = h;
2252 }
2253 ~OopHandleList() {
2254 assert(_index == _count, "usage error");
2255 for (int i = 0; i < _index; i++) {
2256 _handles[i].release(JavaThread::thread_oop_storage());
2257 }
2258 }
2259 OopHandleList* next() const { return _next; }
2260 };
2261
2262 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2263
2264 // Called by the ServiceThread to do the work of releasing
2265 // the OopHandles.
2266 void JavaThread::release_oop_handles() {
2267 OopHandleList* list;
2268 {
2269 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2270 list = _oop_handle_list;
2271 _oop_handle_list = nullptr;
2272 }
2273 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2274
2275 while (list != nullptr) {
2276 OopHandleList* l = list;
2277 list = l->next();
2278 delete l;
2279 }
2280 }
2281
2282 // Add our OopHandles for later release.
2283 void JavaThread::add_oop_handles_for_release() {
2284 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2285 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2286 new_head->add(_threadObj);
2287 new_head->add(_vthread);
2288 new_head->add(_jvmti_vthread);
2289 new_head->add(_scopedValueCache);
2290 _oop_handle_list = new_head;
2291 Service_lock->notify_all();
2292 }
2293
2294 #if INCLUDE_JFR
2295 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2296 assert(result != freeze_ok, "sanity check");
2297 _last_freeze_fail_result = result;
2298 _last_freeze_fail_time = Ticks::now();
2299 }
2300
2301 // Post jdk.VirtualThreadPinned event
2302 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2303 assert(result != freeze_ok, "sanity check");
2304 if (event->should_commit()) {
2305 char reason[256];
2306 if (class_to_be_initialized() != nullptr) {
2307 ResourceMark rm(this);
2308 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2309 class_to_be_initialized()->external_name());
2310 event->set_pinnedReason(reason);
2311 } else if (class_being_initialized() != nullptr) {
2312 ResourceMark rm(this);
2313 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2314 class_being_initialized()->external_name());
2315 event->set_pinnedReason(reason);
2316 } else if (result == freeze_pinned_native) {
2317 event->set_pinnedReason("Native or VM frame on stack");
2318 } else {
2319 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2320 event->set_pinnedReason(reason);
2321 }
2322 event->set_blockingOperation(op);
2323 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2324 event->commit();
2325 }
2326 }
2327 #endif
--- EOF ---