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