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/compileTask.hpp"
36 #include "compiler/compilerThread.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/atomic.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/vframeArray.hpp"
92 #include "runtime/vframe_hp.hpp"
93 #include "runtime/vmThread.hpp"
94 #include "runtime/vmOperations.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 _can_call_java(true),
497
498 _preempt_alternate_return(nullptr),
499 _preemption_cancelled(false),
500 _pending_interrupted_exception(false),
501
502 _handshake(this),
503
504 _popframe_preserved_args(nullptr),
505 _popframe_preserved_args_size(0),
506
507 _jvmti_thread_state(nullptr),
508 _interp_only_mode(0),
509 _should_post_on_exceptions_flag(JNI_FALSE),
510 _thread_stat(new ThreadStatistics()),
511
512 _parker(),
513
514 _class_to_be_initialized(nullptr),
515 _class_being_initialized(nullptr),
516
517 _SleepEvent(ParkEvent::Allocate(this)),
518
519 #if INCLUDE_JFR
520 _last_freeze_fail_result(freeze_ok),
521 #endif
522
523 _lock_stack(this),
524 _om_cache(this) {
525 set_jni_functions(jni_functions());
526
527 #if INCLUDE_JVMCI
528 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
529 if (JVMCICounterSize > 0) {
530 resize_counters(0, (int) JVMCICounterSize);
531 }
532 #endif // INCLUDE_JVMCI
533
534 // Setup safepoint state info for this thread
535 ThreadSafepointState::create(this);
536
537 SafepointMechanism::initialize_header(this);
538
539 set_requires_cross_modify_fence(false);
540
541 pd_initialize();
542 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
543 }
544
545 JavaThread* JavaThread::create_attaching_thread() {
546 JavaThread* jt = new JavaThread();
547 jt->_jni_attach_state = _attaching_via_jni;
548 return jt;
549 }
550
551 // interrupt support
552
553 void JavaThread::interrupt() {
554 // All callers should have 'this' thread protected by a
555 // ThreadsListHandle so that it cannot terminate and deallocate
556 // itself.
557 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
558
559 // For Windows _interrupt_event
560 WINDOWS_ONLY(osthread()->set_interrupted(true);)
561
562 // For Thread.sleep
563 _SleepEvent->unpark();
564
565 // For JSR166 LockSupport.park
566 parker()->unpark();
567
568 // For ObjectMonitor and JvmtiRawMonitor
569 _ParkEvent->unpark();
570 }
571
572 bool JavaThread::is_interrupted(bool clear_interrupted) {
573 DEBUG_ONLY(check_for_dangling_thread_pointer(this);)
574
575 if (_threadObj.peek() == nullptr) {
576 // If there is no j.l.Thread then it is impossible to have
577 // been interrupted. We can find null during VM initialization
578 // or when a JNI thread is still in the process of attaching.
579 // In such cases this must be the current thread.
580 assert(this == Thread::current(), "invariant");
581 return false;
582 }
583
584 bool interrupted = java_lang_Thread::interrupted(threadObj());
585
586 // NOTE that since there is no "lock" around the interrupt and
587 // is_interrupted operations, there is the possibility that the
588 // interrupted flag will be "false" but that the
589 // low-level events will be in the signaled state. This is
590 // intentional. The effect of this is that Object.wait() and
591 // LockSupport.park() will appear to have a spurious wakeup, which
592 // is allowed and not harmful, and the possibility is so rare that
593 // it is not worth the added complexity to add yet another lock.
594 // For the sleep event an explicit reset is performed on entry
595 // to JavaThread::sleep, so there is no early return. It has also been
596 // recommended not to put the interrupted flag into the "event"
597 // structure because it hides the issue.
598 // Also, because there is no lock, we must only clear the interrupt
599 // state if we are going to report that we were interrupted; otherwise
600 // an interrupt that happens just after we read the field would be lost.
601 if (interrupted && clear_interrupted) {
602 assert(this == Thread::current(), "only the current thread can clear");
603 java_lang_Thread::set_interrupted(threadObj(), false);
604 WINDOWS_ONLY(osthread()->set_interrupted(false);)
605 }
606 return interrupted;
607 }
608
609 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
610 // the Java code in Object::wait which are not present in RawMonitorWait.
611 bool JavaThread::get_and_clear_interrupted() {
612 if (!is_interrupted(false)) {
613 return false;
614 }
615 oop thread_oop = vthread_or_thread();
616 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
617
618 if (!is_virtual) {
619 return is_interrupted(true);
620 }
621 // Virtual thread: clear interrupt status for both virtual and
622 // carrier threads under the interruptLock protection.
623 JavaThread* current = JavaThread::current();
624 HandleMark hm(current);
625 Handle thread_h(current, thread_oop);
626 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
627
628 // re-check the interrupt status under the interruptLock protection
629 bool interrupted = java_lang_Thread::interrupted(thread_h());
630
631 if (interrupted) {
632 assert(this == Thread::current(), "only the current thread can clear");
633 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
634 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
635 WINDOWS_ONLY(osthread()->set_interrupted(false);)
636 }
637 return interrupted;
638 }
639
640 void JavaThread::block_if_vm_exited() {
641 if (_terminated == _vm_exited) {
642 // _vm_exited is set at safepoint, and Threads_lock is never released
643 // so we will block here forever.
644 // Here we can be doing a jump from a safe state to an unsafe state without
645 // proper transition, but it happens after the final safepoint has begun so
646 // this jump won't cause any safepoint problems.
647 set_thread_state(_thread_in_vm);
648 Threads_lock->lock();
649 ShouldNotReachHere();
650 }
651 }
652
653 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
654 set_entry_point(entry_point);
655 // Create the native thread itself.
656 // %note runtime_23
657 os::ThreadType thr_type = os::java_thread;
658 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
659 os::java_thread;
660 os::create_thread(this, thr_type, stack_sz);
661 // The _osthread may be null here because we ran out of memory (too many threads active).
662 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
663 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
664 // the exception consists of creating the exception object & initializing it, initialization
665 // will leave the VM via a JavaCall and then all locks must be unlocked).
666 //
667 // The thread is still suspended when we reach here. Thread must be explicit started
668 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
669 // by calling Threads:add. The reason why this is not done here, is because the thread
670 // object must be fully initialized (take a look at JVM_Start)
671 }
672
673 JavaThread::~JavaThread() {
674
675 // Enqueue OopHandles for release by the service thread.
676 add_oop_handles_for_release();
677
678 // Return the sleep event to the free list
679 ParkEvent::Release(_SleepEvent);
680 _SleepEvent = nullptr;
681
682 // Free any remaining previous UnrollBlock
683 vframeArray* old_array = vframe_array_last();
684
685 if (old_array != nullptr) {
686 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
687 old_array->set_unroll_block(nullptr);
688 delete old_info;
689 delete old_array;
690 }
691
692 JvmtiDeferredUpdates* updates = deferred_updates();
693 if (updates != nullptr) {
694 // This can only happen if thread is destroyed before deoptimization occurs.
695 assert(updates->count() > 0, "Updates holder not deleted");
696 // free deferred updates.
697 delete updates;
698 set_deferred_updates(nullptr);
699 }
700
701 // All Java related clean up happens in exit
702 ThreadSafepointState::destroy(this);
703 if (_thread_stat != nullptr) delete _thread_stat;
704
705 #if INCLUDE_JVMCI
706 if (JVMCICounterSize > 0) {
707 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
708 }
709 #endif // INCLUDE_JVMCI
710 }
711
712
713 // First JavaThread specific code executed by a new Java thread.
714 void JavaThread::pre_run() {
715 // empty - see comments in run()
716 }
717
718 // The main routine called by a new Java thread. This isn't overridden
719 // by subclasses, instead different subclasses define a different "entry_point"
720 // which defines the actual logic for that kind of thread.
721 void JavaThread::run() {
722 // initialize thread-local alloc buffer related fields
723 initialize_tlab();
724
725 _stack_overflow_state.create_stack_guard_pages();
726
727 cache_global_variables();
728
729 // Thread is now sufficiently initialized to be handled by the safepoint code as being
730 // in the VM. Change thread state from _thread_new to _thread_in_vm
731 assert(this->thread_state() == _thread_new, "wrong thread state");
732 set_thread_state(_thread_in_vm);
733
734 // Before a thread is on the threads list it is always safe, so after leaving the
735 // _thread_new we should emit a instruction barrier. The distance to modified code
736 // from here is probably far enough, but this is consistent and safe.
737 OrderAccess::cross_modify_fence();
738
739 assert(JavaThread::current() == this, "sanity check");
740 assert(!Thread::current()->owns_locks(), "sanity check");
741
742 DTRACE_THREAD_PROBE(start, this);
743
744 // This operation might block. We call that after all safepoint checks for a new thread has
745 // been completed.
746 set_active_handles(JNIHandleBlock::allocate_block());
747
748 if (JvmtiExport::should_post_thread_life()) {
749 JvmtiExport::post_thread_start(this);
750
751 }
752
753 if (AlwaysPreTouchStacks) {
754 pretouch_stack();
755 }
756
757 // We call another function to do the rest so we are sure that the stack addresses used
758 // from there will be lower than the stack base just computed.
759 thread_main_inner();
760 }
761
762 void JavaThread::thread_main_inner() {
763 assert(JavaThread::current() == this, "sanity check");
764 assert(_threadObj.peek() != nullptr, "just checking");
765
766 // Execute thread entry point unless this thread has a pending exception.
767 // Note: Due to JVMTI StopThread we can have pending exceptions already!
768 if (!this->has_pending_exception()) {
769 {
770 ResourceMark rm(this);
771 this->set_native_thread_name(this->name());
772 }
773 HandleMark hm(this);
774 this->entry_point()(this, this);
775 }
776
777 DTRACE_THREAD_PROBE(stop, this);
778
779 // Cleanup is handled in post_run()
780 }
781
782 // Shared teardown for all JavaThreads
783 void JavaThread::post_run() {
784 this->exit(false);
785 this->unregister_thread_stack_with_NMT();
786 // Defer deletion to here to ensure 'this' is still referenceable in call_run
787 // for any shared tear-down.
788 this->smr_delete();
789 }
790
791 static void ensure_join(JavaThread* thread) {
792 // We do not need to grab the Threads_lock, since we are operating on ourself.
793 Handle threadObj(thread, thread->threadObj());
794 assert(threadObj.not_null(), "java thread object must exist");
795 ObjectLocker lock(threadObj, thread);
796 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
797 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
798 // Clear the native thread instance - this makes isAlive return false and allows the join()
799 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
800 // requirements.
801 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
802 java_lang_Thread::release_set_thread(threadObj(), nullptr);
803 lock.notify_all(thread);
804 // Ignore pending exception, since we are exiting anyway
805 thread->clear_pending_exception();
806 }
807
808 static bool is_daemon(oop threadObj) {
809 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
810 }
811
812 // For any new cleanup additions, please check to see if they need to be applied to
813 // cleanup_failed_attach_current_thread as well.
814 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
815 assert(this == JavaThread::current(), "thread consistency check");
816 assert(!is_exiting(), "should not be exiting or terminated already");
817
818 elapsedTimer _timer_exit_phase1;
819 elapsedTimer _timer_exit_phase2;
820 elapsedTimer _timer_exit_phase3;
821 elapsedTimer _timer_exit_phase4;
822
823 om_clear_monitor_cache();
824
825 if (log_is_enabled(Debug, os, thread, timer)) {
826 _timer_exit_phase1.start();
827 }
828
829 HandleMark hm(this);
830 Handle uncaught_exception(this, this->pending_exception());
831 this->clear_pending_exception();
832 Handle threadObj(this, this->threadObj());
833 assert(threadObj.not_null(), "Java thread object should be created");
834
835 if (!destroy_vm) {
836 if (uncaught_exception.not_null()) {
837 EXCEPTION_MARK;
838 // Call method Thread.dispatchUncaughtException().
839 Klass* thread_klass = vmClasses::Thread_klass();
840 JavaValue result(T_VOID);
841 JavaCalls::call_virtual(&result,
842 threadObj, thread_klass,
843 vmSymbols::dispatchUncaughtException_name(),
844 vmSymbols::throwable_void_signature(),
845 uncaught_exception,
846 THREAD);
847 if (HAS_PENDING_EXCEPTION) {
848 ResourceMark rm(this);
849 jio_fprintf(defaultStream::error_stream(),
850 "\nException: %s thrown from the UncaughtExceptionHandler"
851 " in thread \"%s\"\n",
852 pending_exception()->klass()->external_name(),
853 name());
854 CLEAR_PENDING_EXCEPTION;
855 }
856 }
857
858 if (!is_Compiler_thread()) {
859 // We have finished executing user-defined Java code and now have to do the
860 // implementation specific clean-up by calling Thread.exit(). We prevent any
861 // asynchronous exceptions from being delivered while in Thread.exit()
862 // to ensure the clean-up is not corrupted.
863 NoAsyncExceptionDeliveryMark _no_async(this);
864
865 EXCEPTION_MARK;
866 JavaValue result(T_VOID);
867 Klass* thread_klass = vmClasses::Thread_klass();
868 JavaCalls::call_virtual(&result,
869 threadObj, thread_klass,
870 vmSymbols::exit_method_name(),
871 vmSymbols::void_method_signature(),
872 THREAD);
873 CLEAR_PENDING_EXCEPTION;
874 }
875
876 // notify JVMTI
877 if (JvmtiExport::should_post_thread_life()) {
878 JvmtiExport::post_thread_end(this);
879 }
880 } else {
881 // before_exit() has already posted JVMTI THREAD_END events
882 }
883
884 // Cleanup any pending async exception now since we cannot access oops after
885 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
886 if (has_async_exception_condition()) {
887 handshake_state()->clean_async_exception_operation();
888 }
889
890 // The careful dance between thread suspension and exit is handled here.
891 // Since we are in thread_in_vm state and suspension is done with handshakes,
892 // we can just put in the exiting state and it will be correctly handled.
893 // Also, no more async exceptions will be added to the queue after this point.
894 set_terminated(_thread_exiting);
895 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
896
897 if (log_is_enabled(Debug, os, thread, timer)) {
898 _timer_exit_phase1.stop();
899 _timer_exit_phase2.start();
900 }
901
902 // Capture daemon status before the thread is marked as terminated.
903 bool daemon = is_daemon(threadObj());
904
905 // Notify waiters on thread object. This has to be done after exit() is called
906 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
907 // group should have the destroyed bit set before waiters are notified).
908 ensure_join(this);
909 assert(!this->has_pending_exception(), "ensure_join should have cleared");
910
911 if (log_is_enabled(Debug, os, thread, timer)) {
912 _timer_exit_phase2.stop();
913 _timer_exit_phase3.start();
914 }
915 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
916 // held by this thread must be released. The spec does not distinguish
917 // between JNI-acquired and regular Java monitors. We can only see
918 // regular Java monitors here if monitor enter-exit matching is broken.
919 //
920 // ensure_join() ignores IllegalThreadStateExceptions, and so does
921 // ObjectSynchronizer::release_monitors_owned_by_thread().
922 if (exit_type == jni_detach) {
923 // Sanity check even though JNI DetachCurrentThread() would have
924 // returned JNI_ERR if there was a Java frame. JavaThread exit
925 // should be done executing Java code by the time we get here.
926 assert(!this->has_last_Java_frame(),
927 "should not have a Java frame when detaching or exiting");
928 ObjectSynchronizer::release_monitors_owned_by_thread(this);
929 assert(!this->has_pending_exception(), "release_monitors should have cleared");
930 // Check for monitor counts being out of sync.
931 assert(held_monitor_count() == jni_monitor_count(),
932 "held monitor count should be equal to jni: %zd != %zd",
933 held_monitor_count(), jni_monitor_count());
934 // All in-use monitors, including JNI-locked ones, should have been released above.
935 assert(held_monitor_count() == 0, "Failed to unlock %zd object monitors",
936 held_monitor_count());
937 } else {
938 // Check for monitor counts being out of sync.
939 assert(held_monitor_count() == jni_monitor_count(),
940 "held monitor count should be equal to jni: %zd != %zd",
941 held_monitor_count(), jni_monitor_count());
942 // It is possible that a terminating thread failed to unlock monitors it locked
943 // via JNI so we don't assert the count is zero.
944 }
945
946 if (CheckJNICalls && jni_monitor_count() > 0) {
947 // We would like a fatal here, but due to we never checked this before there
948 // is a lot of tests which breaks, even with an error log.
949 log_debug(jni)("JavaThread %s (tid: %zu) with Objects still locked by JNI MonitorEnter.",
950 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
951 }
952
953 // These things needs to be done while we are still a Java Thread. Make sure that thread
954 // is in a consistent state, in case GC happens
955 JFR_ONLY(Jfr::on_thread_exit(this);)
956
957 if (active_handles() != nullptr) {
958 JNIHandleBlock* block = active_handles();
959 set_active_handles(nullptr);
960 JNIHandleBlock::release_block(block);
961 }
962
963 if (free_handle_block() != nullptr) {
964 JNIHandleBlock* block = free_handle_block();
965 set_free_handle_block(nullptr);
966 JNIHandleBlock::release_block(block);
967 }
968
969 // These have to be removed while this is still a valid thread.
970 _stack_overflow_state.remove_stack_guard_pages();
971
972 if (UseTLAB) {
973 retire_tlab();
974 }
975
976 if (JvmtiEnv::environments_might_exist()) {
977 JvmtiExport::cleanup_thread(this);
978 }
979
980 // We need to cache the thread name for logging purposes below as once
981 // we have called on_thread_detach this thread must not access any oops.
982 char* thread_name = nullptr;
983 if (log_is_enabled(Debug, os, thread, timer) || (CountBytecodesPerThread && log_is_enabled(Info, init))) {
984 ResourceMark rm(this);
985 thread_name = os::strdup(name());
986 }
987
988 if (log_is_enabled(Info, os, thread)) {
989 ResourceMark rm(this);
990 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: %zu).",
991 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
992 name(), os::current_thread_id());
993 }
994
995 if (log_is_enabled(Debug, os, thread, timer)) {
996 _timer_exit_phase3.stop();
997 _timer_exit_phase4.start();
998 }
999
1000 #if INCLUDE_JVMCI
1001 if (JVMCICounterSize > 0) {
1002 if (jvmci_counters_include(this)) {
1003 for (int i = 0; i < JVMCICounterSize; i++) {
1004 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1005 }
1006 }
1007 }
1008 #endif // INCLUDE_JVMCI
1009
1010 if (bc_counter_value() > 0) {
1011 log_info(init)("Thread '%s': " JLONG_FORMAT " bytecodes executed (during clinit: " JLONG_FORMAT ")",
1012 thread_name, bc_counter_value(), clinit_bc_counter_value());
1013 }
1014
1015 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1016 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1017 Threads::remove(this, daemon);
1018
1019 if (log_is_enabled(Debug, os, thread, timer)) {
1020 _timer_exit_phase4.stop();
1021 log_debug(os, thread, timer)("name='%s'"
1022 ", exit-phase1=" JLONG_FORMAT
1023 ", exit-phase2=" JLONG_FORMAT
1024 ", exit-phase3=" JLONG_FORMAT
1025 ", exit-phase4=" JLONG_FORMAT,
1026 thread_name,
1027 _timer_exit_phase1.milliseconds(),
1028 _timer_exit_phase2.milliseconds(),
1029 _timer_exit_phase3.milliseconds(),
1030 _timer_exit_phase4.milliseconds());
1031 os::free(thread_name);
1032 }
1033 }
1034
1035 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1036 if (active_handles() != nullptr) {
1037 JNIHandleBlock* block = active_handles();
1038 set_active_handles(nullptr);
1039 JNIHandleBlock::release_block(block);
1040 }
1041
1042 if (free_handle_block() != nullptr) {
1043 JNIHandleBlock* block = free_handle_block();
1044 set_free_handle_block(nullptr);
1045 JNIHandleBlock::release_block(block);
1046 }
1047
1048 // These have to be removed while this is still a valid thread.
1049 _stack_overflow_state.remove_stack_guard_pages();
1050
1051 if (UseTLAB) {
1052 retire_tlab();
1053 }
1054
1055 Threads::remove(this, is_daemon);
1056 }
1057
1058 JavaThread* JavaThread::active() {
1059 Thread* thread = Thread::current();
1060 if (thread->is_Java_thread()) {
1061 return JavaThread::cast(thread);
1062 } else {
1063 assert(thread->is_VM_thread(), "this must be a vm thread");
1064 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1065 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1066 return ret;
1067 }
1068 }
1069
1070 bool JavaThread::is_lock_owned(address adr) const {
1071 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1072 return is_in_full_stack(adr);
1073 }
1074
1075 oop JavaThread::exception_oop() const {
1076 return Atomic::load(&_exception_oop);
1077 }
1078
1079 void JavaThread::set_exception_oop(oop o) {
1080 Atomic::store(&_exception_oop, o);
1081 }
1082
1083 void JavaThread::handle_special_runtime_exit_condition() {
1084 if (is_obj_deopt_suspend()) {
1085 frame_anchor()->make_walkable();
1086 wait_for_object_deoptimization();
1087 }
1088 }
1089
1090
1091 // Asynchronous exceptions support
1092 //
1093 void JavaThread::handle_async_exception(oop java_throwable) {
1094 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1095 assert(!is_at_poll_safepoint(), "should have never called this method");
1096
1097 if (has_last_Java_frame()) {
1098 frame f = last_frame();
1099 if (f.is_runtime_frame()) {
1100 // If the topmost frame is a runtime stub, then we are calling into
1101 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1102 // must deoptimize the caller before continuing, as the compiled exception
1103 // handler table may not be valid.
1104 RegisterMap reg_map(this,
1105 RegisterMap::UpdateMap::skip,
1106 RegisterMap::ProcessFrames::include,
1107 RegisterMap::WalkContinuation::skip);
1108 frame compiled_frame = f.sender(®_map);
1109 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1110 Deoptimization::deoptimize(this, compiled_frame);
1111 }
1112 }
1113 }
1114
1115 // We cannot call Exceptions::_throw(...) here because we cannot block
1116 set_pending_exception(java_throwable, __FILE__, __LINE__);
1117
1118 clear_scopedValueBindings();
1119
1120 LogTarget(Info, exceptions) lt;
1121 if (lt.is_enabled()) {
1122 ResourceMark rm;
1123 LogStream ls(lt);
1124 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1125 if (has_last_Java_frame()) {
1126 frame f = last_frame();
1127 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1128 }
1129 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1130 }
1131 }
1132
1133 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1134 // Do not throw asynchronous exceptions against the compiler thread
1135 // or if the thread is already exiting.
1136 if (!can_call_java() || is_exiting()) {
1137 delete aeh;
1138 return;
1139 }
1140
1141 oop exception = aeh->exception();
1142 Handshake::execute(aeh, this); // Install asynchronous handshake
1143
1144 ResourceMark rm;
1145 if (log_is_enabled(Info, exceptions)) {
1146 log_info(exceptions)("Pending Async. exception installed of type: %s",
1147 InstanceKlass::cast(exception->klass())->external_name());
1148 }
1149 // for AbortVMOnException flag
1150 Exceptions::debug_check_abort(exception->klass()->external_name());
1151
1152 oop vt_oop = vthread();
1153 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1154 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1155 java_lang_Thread::set_interrupted(threadObj(), true);
1156 this->interrupt();
1157 }
1158 }
1159
1160 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1161 AsyncExceptionHandshake* _aeh;
1162 public:
1163 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1164 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1165 ~InstallAsyncExceptionHandshake() {
1166 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1167 delete _aeh;
1168 }
1169 void do_thread(Thread* thr) {
1170 JavaThread* target = JavaThread::cast(thr);
1171 target->install_async_exception(_aeh);
1172 _aeh = nullptr;
1173 }
1174 };
1175
1176 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1177 OopHandle e(Universe::vm_global(), java_throwable);
1178 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1179 Handshake::execute(&iaeh, target);
1180 }
1181
1182 #if INCLUDE_JVMTI
1183 void JavaThread::set_is_in_VTMS_transition(bool val) {
1184 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1185 _is_in_VTMS_transition = val;
1186 }
1187
1188 #ifdef ASSERT
1189 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1190 _is_VTMS_transition_disabler = val;
1191 }
1192 #endif
1193 #endif
1194
1195 // External suspension mechanism.
1196 //
1197 // Guarantees on return (for a valid target thread):
1198 // - Target thread will not execute any new bytecode.
1199 // - Target thread will not enter any new monitors.
1200 //
1201 bool JavaThread::java_suspend(bool register_vthread_SR) {
1202 #if INCLUDE_JVMTI
1203 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1204 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1205 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1206 #endif
1207
1208 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1209 "target JavaThread is not protected in calling context.");
1210 return this->handshake_state()->suspend(register_vthread_SR);
1211 }
1212
1213 bool JavaThread::java_resume(bool register_vthread_SR) {
1214 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1215 "missing ThreadsListHandle in calling context.");
1216 return this->handshake_state()->resume(register_vthread_SR);
1217 }
1218
1219 // Wait for another thread to perform object reallocation and relocking on behalf of
1220 // this thread. The current thread is required to change to _thread_blocked in order
1221 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1222 // handshake safe, the other thread can complete the handshake used to synchronize
1223 // with this thread and then perform the reallocation and relocking.
1224 // See EscapeBarrier::sync_and_suspend_*()
1225
1226 void JavaThread::wait_for_object_deoptimization() {
1227 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1228 assert(this == Thread::current(), "invariant");
1229
1230 bool spin_wait = os::is_MP();
1231 do {
1232 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1233 // Wait for object deoptimization if requested.
1234 if (spin_wait) {
1235 // A single deoptimization is typically very short. Microbenchmarks
1236 // showed 5% better performance when spinning.
1237 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1238 SpinYield spin(spin_limit);
1239 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1240 spin.wait();
1241 }
1242 // Spin just once
1243 spin_wait = false;
1244 } else {
1245 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1246 if (is_obj_deopt_suspend()) {
1247 ml.wait();
1248 }
1249 }
1250 // A handshake for obj. deoptimization suspend could have been processed so
1251 // we must check after processing.
1252 } while (is_obj_deopt_suspend());
1253 }
1254
1255 #ifdef ASSERT
1256 // Verify the JavaThread has not yet been published in the Threads::list, and
1257 // hence doesn't need protection from concurrent access at this stage.
1258 void JavaThread::verify_not_published() {
1259 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1260 // since an unpublished JavaThread doesn't participate in the
1261 // Thread-SMR protocol for keeping a ThreadsList alive.
1262 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1263 }
1264 #endif
1265
1266 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1267 // pending, when _suspend_flags is non-zero or when we need to process a stack
1268 // watermark. Also check for pending async exceptions (except unsafe access error).
1269 // Note only the native==>Java barriers can call this function when thread state
1270 // is _thread_in_native_trans.
1271 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1272 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1273 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1274
1275 thread->set_thread_state(_thread_in_vm);
1276
1277 // Enable WXWrite: called directly from interpreter native wrapper.
1278 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1279
1280 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1281
1282 // After returning from native, it could be that the stack frames are not
1283 // yet safe to use. We catch such situations in the subsequent stack watermark
1284 // barrier, which will trap unsafe stack frames.
1285 StackWatermarkSet::before_unwind(thread);
1286 }
1287
1288 #ifndef PRODUCT
1289 // Deoptimization
1290 // Function for testing deoptimization
1291 void JavaThread::deoptimize() {
1292 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1293 bool deopt = false; // Dump stack only if a deopt actually happens.
1294 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1295 // Iterate over all frames in the thread and deoptimize
1296 for (; !fst.is_done(); fst.next()) {
1297 if (fst.current()->can_be_deoptimized()) {
1298
1299 if (only_at) {
1300 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1301 // consists of comma or carriage return separated numbers so
1302 // search for the current bci in that string.
1303 address pc = fst.current()->pc();
1304 nmethod* nm = fst.current()->cb()->as_nmethod();
1305 ScopeDesc* sd = nm->scope_desc_at(pc);
1306 char buffer[8];
1307 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1308 size_t len = strlen(buffer);
1309 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1310 while (found != nullptr) {
1311 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1312 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1313 // Check that the bci found is bracketed by terminators.
1314 break;
1315 }
1316 found = strstr(found + 1, buffer);
1317 }
1318 if (!found) {
1319 continue;
1320 }
1321 }
1322
1323 if (DebugDeoptimization && !deopt) {
1324 deopt = true; // One-time only print before deopt
1325 tty->print_cr("[BEFORE Deoptimization]");
1326 trace_frames();
1327 trace_stack();
1328 }
1329 Deoptimization::deoptimize(this, *fst.current());
1330 }
1331 }
1332
1333 if (DebugDeoptimization && deopt) {
1334 tty->print_cr("[AFTER Deoptimization]");
1335 trace_frames();
1336 }
1337 }
1338
1339
1340 // Make zombies
1341 void JavaThread::make_zombies() {
1342 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1343 if (fst.current()->can_be_deoptimized()) {
1344 // it is a Java nmethod
1345 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1346 assert(nm != nullptr, "did not find nmethod");
1347 nm->make_not_entrant("zombie");
1348 }
1349 }
1350 }
1351 #endif // PRODUCT
1352
1353
1354 void JavaThread::deoptimize_marked_methods() {
1355 if (!has_last_Java_frame()) return;
1356 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1357 for (; !fst.is_done(); fst.next()) {
1358 if (fst.current()->should_be_deoptimized()) {
1359 Deoptimization::deoptimize(this, *fst.current());
1360 }
1361 }
1362 }
1363
1364 #ifdef ASSERT
1365 void JavaThread::verify_frame_info() {
1366 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1367 (has_last_Java_frame() && java_call_counter() > 0),
1368 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1369 has_last_Java_frame() ? "true" : "false", java_call_counter());
1370 }
1371 #endif
1372
1373 // Push on a new block of JNI handles.
1374 void JavaThread::push_jni_handle_block() {
1375 // Allocate a new block for JNI handles.
1376 // Inlined code from jni_PushLocalFrame()
1377 JNIHandleBlock* old_handles = active_handles();
1378 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1379 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1380 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1381 set_active_handles(new_handles);
1382 }
1383
1384 // Pop off the current block of JNI handles.
1385 void JavaThread::pop_jni_handle_block() {
1386 // Release our JNI handle block
1387 JNIHandleBlock* old_handles = active_handles();
1388 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1389 assert(new_handles != nullptr, "should never set active handles to null");
1390 set_active_handles(new_handles);
1391 old_handles->set_pop_frame_link(nullptr);
1392 JNIHandleBlock::release_block(old_handles, this);
1393 }
1394
1395 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1396 // Verify that the deferred card marks have been flushed.
1397 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1398
1399 // Traverse the GCHandles
1400 Thread::oops_do_no_frames(f, cf);
1401
1402 if (active_handles() != nullptr) {
1403 active_handles()->oops_do(f);
1404 }
1405
1406 DEBUG_ONLY(verify_frame_info();)
1407
1408 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1409 // If we have deferred set_locals there might be oops waiting to be
1410 // written
1411 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1412 if (list != nullptr) {
1413 for (int i = 0; i < list->length(); i++) {
1414 list->at(i)->oops_do(f);
1415 }
1416 }
1417
1418 // Traverse instance variables at the end since the GC may be moving things
1419 // around using this function
1420 f->do_oop((oop*) &_vm_result_oop);
1421 f->do_oop((oop*) &_exception_oop);
1422 #if INCLUDE_JVMCI
1423 f->do_oop((oop*) &_jvmci_reserved_oop0);
1424
1425 if (_live_nmethod != nullptr && cf != nullptr) {
1426 cf->do_nmethod(_live_nmethod);
1427 }
1428 #endif
1429
1430 if (jvmti_thread_state() != nullptr) {
1431 jvmti_thread_state()->oops_do(f, cf);
1432 }
1433
1434 // The continuation oops are really on the stack. But there is typically at most
1435 // one of those per thread, so we handle them here in the oops_do_no_frames part
1436 // so that we don't have to sprinkle as many stack watermark checks where these
1437 // oops are used. We just need to make sure the thread has started processing.
1438 ContinuationEntry* entry = _cont_entry;
1439 while (entry != nullptr) {
1440 f->do_oop((oop*)entry->cont_addr());
1441 f->do_oop((oop*)entry->chunk_addr());
1442 entry = entry->parent();
1443 }
1444
1445 if (LockingMode == LM_LIGHTWEIGHT) {
1446 lock_stack().oops_do(f);
1447 }
1448 }
1449
1450 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1451 if (!has_last_Java_frame()) {
1452 return;
1453 }
1454 // Finish any pending lazy GC activity for the frames
1455 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1456 // Traverse the execution stack
1457 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1458 fst.current()->oops_do(f, cf, fst.register_map());
1459 }
1460 }
1461
1462 #ifdef ASSERT
1463 void JavaThread::verify_states_for_handshake() {
1464 // This checks that the thread has a correct frame state during a handshake.
1465 verify_frame_info();
1466 }
1467 #endif
1468
1469 void JavaThread::nmethods_do(NMethodClosure* cf) {
1470 DEBUG_ONLY(verify_frame_info();)
1471 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1472
1473 if (has_last_Java_frame()) {
1474 // Traverse the execution stack
1475 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1476 fst.current()->nmethod_do(cf);
1477 }
1478 }
1479
1480 if (jvmti_thread_state() != nullptr) {
1481 jvmti_thread_state()->nmethods_do(cf);
1482 }
1483
1484 #if INCLUDE_JVMCI
1485 if (_live_nmethod != nullptr) {
1486 cf->do_nmethod(_live_nmethod);
1487 }
1488 #endif
1489 }
1490
1491 void JavaThread::metadata_do(MetadataClosure* f) {
1492 if (has_last_Java_frame()) {
1493 // Traverse the execution stack to call f() on the methods in the stack
1494 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1495 fst.current()->metadata_do(f);
1496 }
1497 } else if (is_Compiler_thread()) {
1498 // need to walk ciMetadata in current compile tasks to keep alive.
1499 CompilerThread* ct = (CompilerThread*)this;
1500 if (ct->env() != nullptr) {
1501 ct->env()->metadata_do(f);
1502 }
1503 CompileTask* task = ct->task();
1504 if (task != nullptr) {
1505 task->metadata_do(f);
1506 }
1507 }
1508 }
1509
1510 // Printing
1511 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1512 switch (_thread_state) {
1513 case _thread_uninitialized: return "_thread_uninitialized";
1514 case _thread_new: return "_thread_new";
1515 case _thread_new_trans: return "_thread_new_trans";
1516 case _thread_in_native: return "_thread_in_native";
1517 case _thread_in_native_trans: return "_thread_in_native_trans";
1518 case _thread_in_vm: return "_thread_in_vm";
1519 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1520 case _thread_in_Java: return "_thread_in_Java";
1521 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1522 case _thread_blocked: return "_thread_blocked";
1523 case _thread_blocked_trans: return "_thread_blocked_trans";
1524 default: return "unknown thread state";
1525 }
1526 }
1527
1528 void JavaThread::print_thread_state_on(outputStream *st) const {
1529 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1530 }
1531
1532 // Called by Threads::print() for VM_PrintThreads operation
1533 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1534 st->print_raw("\"");
1535 st->print_raw(name());
1536 st->print_raw("\" ");
1537 oop thread_oop = threadObj();
1538 if (thread_oop != nullptr) {
1539 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1540 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1541 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1542 }
1543 Thread::print_on(st, print_extended_info);
1544 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1545 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1546 if (thread_oop != nullptr) {
1547 if (is_vthread_mounted()) {
1548 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, java_lang_Thread::thread_id(vthread()));
1549 } else {
1550 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1551 }
1552 }
1553 #ifndef PRODUCT
1554 _safepoint_state->print_on(st);
1555 #endif // PRODUCT
1556 if (is_Compiler_thread()) {
1557 CompileTask *task = ((CompilerThread*)this)->task();
1558 if (task != nullptr) {
1559 st->print(" Compiling: ");
1560 task->print(st, nullptr, true, false);
1561 } else {
1562 st->print(" No compile task");
1563 }
1564 st->cr();
1565 }
1566 }
1567
1568 void JavaThread::print() const { print_on(tty); }
1569
1570 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1571 st->print("%s", get_thread_name_string(buf, buflen));
1572 }
1573
1574 // Called by fatal error handler. The difference between this and
1575 // JavaThread::print() is that we can't grab lock or allocate memory.
1576 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1577 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1578 Thread* current = Thread::current_or_null_safe();
1579 assert(current != nullptr, "cannot be called by a detached thread");
1580 st->fill_to(60);
1581 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1582 // Only access threadObj() if current thread is not a JavaThread
1583 // or if it is a JavaThread that can safely access oops.
1584 oop thread_obj = threadObj();
1585 if (thread_obj != nullptr) {
1586 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1587 }
1588 }
1589 st->print(" [");
1590 st->print("%s", _get_thread_state_name(_thread_state));
1591 if (osthread()) {
1592 st->print(", id=%d", osthread()->thread_id());
1593 }
1594 // Use raw field members for stack base/size as this could be
1595 // called before a thread has run enough to initialize them.
1596 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1597 p2i(_stack_base - _stack_size), p2i(_stack_base),
1598 PROPERFMTARGS(_stack_size));
1599 st->print("]");
1600
1601 ThreadsSMRSupport::print_info_on(this, st);
1602 return;
1603 }
1604
1605
1606 // Verification
1607
1608 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1609 // ignore if there is no stack
1610 if (!has_last_Java_frame()) return;
1611 // traverse the stack frames. Starts from top frame.
1612 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1613 frame* fr = fst.current();
1614 f(fr, fst.register_map());
1615 }
1616 }
1617
1618 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1619
1620 void JavaThread::verify() {
1621 // Verify oops in the thread.
1622 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1623
1624 // Verify the stack frames.
1625 frames_do(frame_verify);
1626 }
1627
1628 // CR 6300358 (sub-CR 2137150)
1629 // Most callers of this method assume that it can't return null but a
1630 // thread may not have a name whilst it is in the process of attaching to
1631 // the VM - see CR 6412693, and there are places where a JavaThread can be
1632 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1633 // if vm exit occurs during initialization). These cases can all be accounted
1634 // for such that this method never returns null.
1635 const char* JavaThread::name() const {
1636 if (Thread::is_JavaThread_protected(/* target */ this)) {
1637 // The target JavaThread is protected so get_thread_name_string() is safe:
1638 return get_thread_name_string();
1639 }
1640
1641 // The target JavaThread is not protected so we return the default:
1642 return Thread::name();
1643 }
1644
1645 // Like name() but doesn't include the protection check. This must only be
1646 // called when it is known to be safe, even though the protection check can't tell
1647 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1648 const char* JavaThread::name_raw() const {
1649 return get_thread_name_string();
1650 }
1651
1652 // Returns a non-null representation of this thread's name, or a suitable
1653 // descriptive string if there is no set name.
1654 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1655 const char* name_str;
1656 #ifdef ASSERT
1657 Thread* current = Thread::current_or_null_safe();
1658 assert(current != nullptr, "cannot be called by a detached thread");
1659 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1660 // Only access threadObj() if current thread is not a JavaThread
1661 // or if it is a JavaThread that can safely access oops.
1662 #endif
1663 oop thread_obj = threadObj();
1664 if (thread_obj != nullptr) {
1665 oop name = java_lang_Thread::name(thread_obj);
1666 if (name != nullptr) {
1667 if (buf == nullptr) {
1668 name_str = java_lang_String::as_utf8_string(name);
1669 } else {
1670 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1671 }
1672 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1673 name_str = "<no-name - thread is attaching>";
1674 } else {
1675 name_str = "<un-named>";
1676 }
1677 } else {
1678 name_str = Thread::name();
1679 }
1680 #ifdef ASSERT
1681 } else {
1682 // Current JavaThread has exited...
1683 if (current == this) {
1684 // ... and is asking about itself:
1685 name_str = "<no-name - current JavaThread has exited>";
1686 } else {
1687 // ... and it can't safely determine this JavaThread's name so
1688 // use the default thread name.
1689 name_str = Thread::name();
1690 }
1691 }
1692 #endif
1693 assert(name_str != nullptr, "unexpected null thread name");
1694 return name_str;
1695 }
1696
1697 // Helper to extract the name from the thread oop for logging.
1698 const char* JavaThread::name_for(oop thread_obj) {
1699 assert(thread_obj != nullptr, "precondition");
1700 oop name = java_lang_Thread::name(thread_obj);
1701 const char* name_str;
1702 if (name != nullptr) {
1703 name_str = java_lang_String::as_utf8_string(name);
1704 } else {
1705 name_str = "<un-named>";
1706 }
1707 return name_str;
1708 }
1709
1710 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1711
1712 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1713 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1714 // Link Java Thread object <-> C++ Thread
1715
1716 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1717 // and put it into a new Handle. The Handle "thread_oop" can then
1718 // be used to pass the C++ thread object to other methods.
1719
1720 // Set the Java level thread object (jthread) field of the
1721 // new thread (a JavaThread *) to C++ thread object using the
1722 // "thread_oop" handle.
1723
1724 // Set the thread field (a JavaThread *) of the
1725 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1726
1727 Handle thread_oop(Thread::current(),
1728 JNIHandles::resolve_non_null(jni_thread));
1729 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1730 "must be initialized");
1731 set_threadOopHandles(thread_oop());
1732 set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
1733
1734 if (prio == NoPriority) {
1735 prio = java_lang_Thread::priority(thread_oop());
1736 assert(prio != NoPriority, "A valid priority should be present");
1737 }
1738
1739 // Push the Java priority down to the native thread; needs Threads_lock
1740 Thread::set_priority(this, prio);
1741
1742 // Add the new thread to the Threads list and set it in motion.
1743 // We must have threads lock in order to call Threads::add.
1744 // It is crucial that we do not block before the thread is
1745 // added to the Threads list for if a GC happens, then the java_thread oop
1746 // will not be visited by GC.
1747 Threads::add(this);
1748 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1749 // on a ThreadsList. We don't want to wait for the release when the
1750 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1751 // is already visible to JVM/TI via the ThreadsList.
1752 java_lang_Thread::release_set_thread(thread_oop(), this);
1753 }
1754
1755 oop JavaThread::current_park_blocker() {
1756 // Support for JSR-166 locks
1757 oop thread_oop = threadObj();
1758 if (thread_oop != nullptr) {
1759 return java_lang_Thread::park_blocker(thread_oop);
1760 }
1761 return nullptr;
1762 }
1763
1764 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1765 // This is the external format, selecting the platform or vthread
1766 // as applicable, and allowing for a native-only stack.
1767 void JavaThread::print_jni_stack() {
1768 assert(this == JavaThread::current(), "Can't print stack of other threads");
1769 if (!has_last_Java_frame()) {
1770 ResourceMark rm(this);
1771 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1772 if (buf == nullptr) {
1773 tty->print_cr("Unable to print native stack - out of memory");
1774 return;
1775 }
1776 NativeStackPrinter nsp(this);
1777 address lastpc = nullptr;
1778 nsp.print_stack(tty, buf, O_BUFLEN, lastpc,
1779 true /*print_source_info */, -1 /* max stack */ );
1780 } else {
1781 print_active_stack_on(tty);
1782 }
1783 }
1784
1785 void JavaThread::print_stack_on(outputStream* st) {
1786 if (!has_last_Java_frame()) return;
1787
1788 Thread* current_thread = Thread::current();
1789 ResourceMark rm(current_thread);
1790 HandleMark hm(current_thread);
1791
1792 RegisterMap reg_map(this,
1793 RegisterMap::UpdateMap::include,
1794 RegisterMap::ProcessFrames::include,
1795 RegisterMap::WalkContinuation::skip);
1796 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1797 int count = 0;
1798 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1799 if (f->is_java_frame()) {
1800 javaVFrame* jvf = javaVFrame::cast(f);
1801 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1802
1803 // Print out lock information
1804 if (JavaMonitorsInStackTrace) {
1805 jvf->print_lock_info_on(st, false/*is_virtual*/, count);
1806 }
1807 } else {
1808 // Ignore non-Java frames
1809 }
1810
1811 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1812 count++;
1813 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1814 }
1815 }
1816
1817 void JavaThread::print_vthread_stack_on(outputStream* st) {
1818 assert(is_vthread_mounted(), "Caller should have checked this");
1819 assert(has_last_Java_frame(), "must be");
1820
1821 Thread* current_thread = Thread::current();
1822 ResourceMark rm(current_thread);
1823 HandleMark hm(current_thread);
1824
1825 RegisterMap reg_map(this,
1826 RegisterMap::UpdateMap::include,
1827 RegisterMap::ProcessFrames::include,
1828 RegisterMap::WalkContinuation::include);
1829 ContinuationEntry* cont_entry = last_continuation();
1830 vframe* start_vf = last_java_vframe(®_map);
1831 int count = 0;
1832 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1833 // Watch for end of vthread stack
1834 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1835 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1836 if (cont_entry->is_virtual_thread()) {
1837 break;
1838 }
1839 cont_entry = cont_entry->parent();
1840 }
1841 if (f->is_java_frame()) {
1842 javaVFrame* jvf = javaVFrame::cast(f);
1843 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1844
1845 // Print out lock information
1846 if (JavaMonitorsInStackTrace) {
1847 jvf->print_lock_info_on(st, true/*is_virtual*/, count);
1848 }
1849 } else {
1850 // Ignore non-Java frames
1851 }
1852
1853 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1854 count++;
1855 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1856 }
1857 }
1858
1859 void JavaThread::print_active_stack_on(outputStream* st) {
1860 if (is_vthread_mounted()) {
1861 print_vthread_stack_on(st);
1862 } else {
1863 print_stack_on(st);
1864 }
1865 }
1866
1867 #if INCLUDE_JVMTI
1868 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1869 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1870 set_jvmti_vthread(thread_oop);
1871
1872 // unbind current JvmtiThreadState from JavaThread
1873 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1874
1875 // bind new JvmtiThreadState to JavaThread
1876 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1877
1878 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1879 JvmtiThreadState::process_pending_interp_only(this);
1880
1881 return jvmti_thread_state();
1882 }
1883 #endif
1884
1885 // JVMTI PopFrame support
1886 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1887 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1888 if (in_bytes(size_in_bytes) != 0) {
1889 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1890 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1891 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1892 }
1893 }
1894
1895 void* JavaThread::popframe_preserved_args() {
1896 return _popframe_preserved_args;
1897 }
1898
1899 ByteSize JavaThread::popframe_preserved_args_size() {
1900 return in_ByteSize(_popframe_preserved_args_size);
1901 }
1902
1903 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1904 int sz = in_bytes(popframe_preserved_args_size());
1905 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1906 return in_WordSize(sz / wordSize);
1907 }
1908
1909 void JavaThread::popframe_free_preserved_args() {
1910 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1911 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1912 _popframe_preserved_args = nullptr;
1913 _popframe_preserved_args_size = 0;
1914 }
1915
1916 #ifndef PRODUCT
1917
1918 void JavaThread::trace_frames() {
1919 tty->print_cr("[Describe stack]");
1920 int frame_no = 1;
1921 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1922 tty->print(" %d. ", frame_no++);
1923 fst.current()->print_value_on(tty);
1924 tty->cr();
1925 }
1926 }
1927
1928 class PrintAndVerifyOopClosure: public OopClosure {
1929 protected:
1930 template <class T> inline void do_oop_work(T* p) {
1931 oop obj = RawAccess<>::oop_load(p);
1932 if (obj == nullptr) return;
1933 tty->print(INTPTR_FORMAT ": ", p2i(p));
1934 if (oopDesc::is_oop_or_null(obj)) {
1935 if (obj->is_objArray()) {
1936 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1937 } else {
1938 obj->print();
1939 }
1940 } else {
1941 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1942 }
1943 tty->cr();
1944 }
1945 public:
1946 virtual void do_oop(oop* p) { do_oop_work(p); }
1947 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1948 };
1949
1950 #ifdef ASSERT
1951 // Print or validate the layout of stack frames
1952 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1953 ResourceMark rm;
1954 PreserveExceptionMark pm(this);
1955 FrameValues values;
1956 int frame_no = 0;
1957 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1958 fst.current()->describe(values, ++frame_no, fst.register_map());
1959 if (depth == frame_no) break;
1960 }
1961 Continuation::describe(values);
1962 if (validate_only) {
1963 values.validate();
1964 } else {
1965 tty->print_cr("[Describe stack layout]");
1966 values.print(this);
1967 }
1968 }
1969 #endif
1970
1971 void JavaThread::trace_stack_from(vframe* start_vf) {
1972 ResourceMark rm;
1973 int vframe_no = 1;
1974 for (vframe* f = start_vf; f; f = f->sender()) {
1975 if (f->is_java_frame()) {
1976 javaVFrame::cast(f)->print_activation(vframe_no++);
1977 } else {
1978 f->print();
1979 }
1980 if (vframe_no > StackPrintLimit) {
1981 tty->print_cr("...<more frames>...");
1982 return;
1983 }
1984 }
1985 }
1986
1987
1988 void JavaThread::trace_stack() {
1989 if (!has_last_Java_frame()) return;
1990 Thread* current_thread = Thread::current();
1991 ResourceMark rm(current_thread);
1992 HandleMark hm(current_thread);
1993 RegisterMap reg_map(this,
1994 RegisterMap::UpdateMap::include,
1995 RegisterMap::ProcessFrames::include,
1996 RegisterMap::WalkContinuation::skip);
1997 trace_stack_from(last_java_vframe(®_map));
1998 }
1999
2000
2001 #endif // PRODUCT
2002
2003 // Slow-path increment of the held monitor counts. JNI locking is always
2004 // this slow-path.
2005 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2006 #ifdef SUPPORT_MONITOR_COUNT
2007
2008 if (LockingMode != LM_LEGACY) {
2009 // Nothing to do. Just do some sanity check.
2010 assert(_held_monitor_count == 0, "counter should not be used");
2011 assert(_jni_monitor_count == 0, "counter should not be used");
2012 return;
2013 }
2014
2015 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2016 _held_monitor_count += i;
2017 if (jni) {
2018 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2019 _jni_monitor_count += i;
2020 }
2021 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2022 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2023 #endif // SUPPORT_MONITOR_COUNT
2024 }
2025
2026 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2027 // this slow-path.
2028 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2029 #ifdef SUPPORT_MONITOR_COUNT
2030
2031 if (LockingMode != LM_LEGACY) {
2032 // Nothing to do. Just do some sanity check.
2033 assert(_held_monitor_count == 0, "counter should not be used");
2034 assert(_jni_monitor_count == 0, "counter should not be used");
2035 return;
2036 }
2037
2038 _held_monitor_count -= i;
2039 assert(_held_monitor_count >= 0, "Must always be non-negative: %zd", _held_monitor_count);
2040 if (jni) {
2041 _jni_monitor_count -= i;
2042 assert(_jni_monitor_count >= 0, "Must always be non-negative: %zd", _jni_monitor_count);
2043 }
2044 // When a thread is detaching with still owned JNI monitors, the logic that releases
2045 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2046 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2047 // JNI count is directly set to zero.
2048 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2049 "%zd is less than JNI count %zd", _held_monitor_count, _jni_monitor_count);
2050 #endif // SUPPORT_MONITOR_COUNT
2051 }
2052
2053 frame JavaThread::vthread_last_frame() {
2054 assert (is_vthread_mounted(), "Virtual thread not mounted");
2055 return last_frame();
2056 }
2057
2058 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2059 const ContinuationEntry* entry = vthread_continuation();
2060 guarantee (entry != nullptr, "Not a carrier thread");
2061 frame f = entry->to_frame();
2062 if (reg_map->process_frames()) {
2063 entry->flush_stack_processing(this);
2064 }
2065 entry->update_register_map(reg_map);
2066 return f.sender(reg_map);
2067 }
2068
2069 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2070 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2071 }
2072
2073 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2074 assert(reg_map != nullptr, "a map must be given");
2075 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2076 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2077 }
2078 return nullptr;
2079 }
2080
2081 Klass* JavaThread::security_get_caller_class(int depth) {
2082 ResetNoHandleMark rnhm;
2083 HandleMark hm(Thread::current());
2084
2085 vframeStream vfst(this);
2086 vfst.security_get_caller_frame(depth);
2087 if (!vfst.at_end()) {
2088 return vfst.method()->method_holder();
2089 }
2090 return nullptr;
2091 }
2092
2093 // Internal convenience function for millisecond resolution sleeps.
2094 bool JavaThread::sleep(jlong millis) {
2095 jlong nanos;
2096 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2097 // Conversion to nanos would overflow, saturate at max
2098 nanos = max_jlong;
2099 } else {
2100 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2101 }
2102 return sleep_nanos(nanos);
2103 }
2104
2105 // java.lang.Thread.sleep support
2106 // Returns true if sleep time elapsed as expected, and false
2107 // if the thread was interrupted.
2108 bool JavaThread::sleep_nanos(jlong nanos) {
2109 assert(this == Thread::current(), "thread consistency check");
2110 assert(nanos >= 0, "nanos are in range");
2111
2112 ParkEvent * const slp = this->_SleepEvent;
2113 // Because there can be races with thread interruption sending an unpark()
2114 // to the event, we explicitly reset it here to avoid an immediate return.
2115 // The actual interrupt state will be checked before we park().
2116 slp->reset();
2117 // Thread interruption establishes a happens-before ordering in the
2118 // Java Memory Model, so we need to ensure we synchronize with the
2119 // interrupt state.
2120 OrderAccess::fence();
2121
2122 jlong prevtime = os::javaTimeNanos();
2123
2124 jlong nanos_remaining = nanos;
2125
2126 for (;;) {
2127 // interruption has precedence over timing out
2128 if (this->is_interrupted(true)) {
2129 return false;
2130 }
2131
2132 if (nanos_remaining <= 0) {
2133 return true;
2134 }
2135
2136 {
2137 ThreadBlockInVM tbivm(this);
2138 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2139 slp->park_nanos(nanos_remaining);
2140 }
2141
2142 // Update elapsed time tracking
2143 jlong newtime = os::javaTimeNanos();
2144 if (newtime - prevtime < 0) {
2145 // time moving backwards, should only happen if no monotonic clock
2146 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2147 assert(false,
2148 "unexpected time moving backwards detected in JavaThread::sleep()");
2149 } else {
2150 nanos_remaining -= (newtime - prevtime);
2151 }
2152 prevtime = newtime;
2153 }
2154 }
2155
2156 // Last thread running calls java.lang.Shutdown.shutdown()
2157 void JavaThread::invoke_shutdown_hooks() {
2158 HandleMark hm(this);
2159
2160 // We could get here with a pending exception, if so clear it now.
2161 if (this->has_pending_exception()) {
2162 this->clear_pending_exception();
2163 }
2164
2165 EXCEPTION_MARK;
2166 Klass* shutdown_klass =
2167 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2168 THREAD);
2169 if (shutdown_klass != nullptr) {
2170 // SystemDictionary::resolve_or_null will return null if there was
2171 // an exception. If we cannot load the Shutdown class, just don't
2172 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2173 // won't be run. Note that if a shutdown hook was registered,
2174 // the Shutdown class would have already been loaded
2175 // (Runtime.addShutdownHook will load it).
2176 JavaValue result(T_VOID);
2177 JavaCalls::call_static(&result,
2178 shutdown_klass,
2179 vmSymbols::shutdown_name(),
2180 vmSymbols::void_method_signature(),
2181 THREAD);
2182 }
2183 CLEAR_PENDING_EXCEPTION;
2184 }
2185
2186 #ifndef PRODUCT
2187 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2188 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2189 }
2190 #endif
2191
2192 // Helper function to create the java.lang.Thread object for a
2193 // VM-internal thread. The thread will have the given name, and be
2194 // a member of the "system" ThreadGroup.
2195 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2196 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2197
2198 // Initialize thread_oop to put it into the system threadGroup.
2199 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2200 Handle thread_group(THREAD, Universe::system_thread_group());
2201 Handle thread_oop =
2202 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2203 vmSymbols::threadgroup_string_void_signature(),
2204 thread_group,
2205 string,
2206 CHECK_NH);
2207
2208 return thread_oop;
2209 }
2210
2211 // Starts the target JavaThread as a daemon of the given priority, and
2212 // bound to the given java.lang.Thread instance.
2213 // The Threads_lock is held for the duration.
2214 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2215 Handle thread_oop, ThreadPriority prio) {
2216
2217 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2218
2219 MutexLocker mu(current, Threads_lock);
2220
2221 // Initialize the fields of the thread_oop first.
2222 if (prio != NoPriority) {
2223 java_lang_Thread::set_priority(thread_oop(), prio);
2224 // Note: we don't call os::set_priority here. Possibly we should,
2225 // else all threads should call it themselves when they first run.
2226 }
2227
2228 java_lang_Thread::set_daemon(thread_oop());
2229
2230 // Now bind the thread_oop to the target JavaThread.
2231 target->set_threadOopHandles(thread_oop());
2232 target->set_monitor_owner_id(java_lang_Thread::thread_id(thread_oop()));
2233
2234 Threads::add(target); // target is now visible for safepoint/handshake
2235 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2236 // on a ThreadsList. We don't want to wait for the release when the
2237 // Theads_lock is dropped when the 'mu' destructor is run since the
2238 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2239
2240 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2241 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2242 Thread::start(target);
2243 }
2244
2245 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2246 // At this point it may be possible that no osthread was created for the
2247 // JavaThread due to lack of resources. However, since this must work
2248 // for critical system threads just check and abort if this fails.
2249 if (thread->osthread() == nullptr) {
2250 // This isn't really an OOM condition, but historically this is what
2251 // we report.
2252 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2253 os::native_thread_creation_failed_msg());
2254 }
2255 }
2256
2257 void JavaThread::pretouch_stack() {
2258 // Given an established java thread stack with usable area followed by
2259 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2260 // from the current frame down to the start of the shadow zone.
2261 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2262 if (is_in_full_stack(end)) {
2263 char* p1 = (char*) alloca(1);
2264 address here = (address) &p1;
2265 if (is_in_full_stack(here) && here > end) {
2266 size_t to_alloc = here - end;
2267 char* p2 = (char*) alloca(to_alloc);
2268 log_trace(os, thread)("Pretouching thread stack for %zu: " RANGEFMT ".",
2269 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2270 os::pretouch_memory(p2, p2 + to_alloc,
2271 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2272 }
2273 }
2274 }
2275
2276 // Deferred OopHandle release support.
2277
2278 class OopHandleList : public CHeapObj<mtInternal> {
2279 static const int _count = 4;
2280 OopHandle _handles[_count];
2281 OopHandleList* _next;
2282 int _index;
2283 public:
2284 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2285 void add(OopHandle h) {
2286 assert(_index < _count, "too many additions");
2287 _handles[_index++] = h;
2288 }
2289 ~OopHandleList() {
2290 assert(_index == _count, "usage error");
2291 for (int i = 0; i < _index; i++) {
2292 _handles[i].release(JavaThread::thread_oop_storage());
2293 }
2294 }
2295 OopHandleList* next() const { return _next; }
2296 };
2297
2298 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2299
2300 // Called by the ServiceThread to do the work of releasing
2301 // the OopHandles.
2302 void JavaThread::release_oop_handles() {
2303 OopHandleList* list;
2304 {
2305 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2306 list = _oop_handle_list;
2307 _oop_handle_list = nullptr;
2308 }
2309 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2310
2311 while (list != nullptr) {
2312 OopHandleList* l = list;
2313 list = l->next();
2314 delete l;
2315 }
2316 }
2317
2318 // Add our OopHandles for later release.
2319 void JavaThread::add_oop_handles_for_release() {
2320 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2321 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2322 new_head->add(_threadObj);
2323 new_head->add(_vthread);
2324 new_head->add(_jvmti_vthread);
2325 new_head->add(_scopedValueCache);
2326 _oop_handle_list = new_head;
2327 Service_lock->notify_all();
2328 }
2329
2330 #if INCLUDE_JFR
2331 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2332 assert(result != freeze_ok, "sanity check");
2333 _last_freeze_fail_result = result;
2334 _last_freeze_fail_time = Ticks::now();
2335 }
2336
2337 // Post jdk.VirtualThreadPinned event
2338 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2339 assert(result != freeze_ok, "sanity check");
2340 if (event->should_commit()) {
2341 char reason[256];
2342 if (class_to_be_initialized() != nullptr) {
2343 ResourceMark rm(this);
2344 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2345 class_to_be_initialized()->external_name());
2346 event->set_pinnedReason(reason);
2347 } else if (class_being_initialized() != nullptr) {
2348 ResourceMark rm(this);
2349 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2350 class_being_initialized()->external_name());
2351 event->set_pinnedReason(reason);
2352 } else if (result == freeze_pinned_native) {
2353 event->set_pinnedReason("Native or VM frame on stack");
2354 } else {
2355 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2356 event->set_pinnedReason(reason);
2357 }
2358 event->set_blockingOperation(op);
2359 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2360 event->commit();
2361 }
2362 }
2363 #endif