1 /*
2 * Copyright (c) 1997, 2024, 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 "precompiled.hpp"
27 #include "cds/dynamicArchive.hpp"
28 #include "ci/ciEnv.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/javaThreadStatus.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmClasses.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/codeCache.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/oopStorage.hpp"
39 #include "gc/shared/oopStorageSet.hpp"
40 #include "gc/shared/tlab_globals.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jvm.h"
43 #include "jvmtifiles/jvmtiEnv.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logAsyncWriter.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/allocation.inline.hpp"
48 #include "memory/iterator.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/access.inline.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oopHandle.inline.hpp"
55 #include "oops/verifyOopClosure.hpp"
56 #include "prims/jvm_misc.hpp"
57 #include "prims/jvmtiDeferredUpdates.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/continuation.hpp"
62 #include "runtime/continuationEntry.inline.hpp"
63 #include "runtime/continuationHelper.inline.hpp"
64 #include "runtime/deoptimization.hpp"
65 #include "runtime/frame.inline.hpp"
66 #include "runtime/handles.inline.hpp"
67 #include "runtime/handshake.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/javaCalls.hpp"
71 #include "runtime/javaThread.inline.hpp"
72 #include "runtime/jniHandles.inline.hpp"
73 #include "runtime/lockStack.inline.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.hpp"
76 #include "runtime/os.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/stackFrameStream.inline.hpp"
83 #include "runtime/stackWatermarkSet.hpp"
84 #include "runtime/synchronizer.hpp"
85 #include "runtime/threadCritical.hpp"
86 #include "runtime/threadIdentifier.hpp"
87 #include "runtime/threadSMR.inline.hpp"
88 #include "runtime/threadStatisticalInfo.hpp"
89 #include "runtime/threadWXSetters.inline.hpp"
90 #include "runtime/timer.hpp"
91 #include "runtime/timerTrace.hpp"
92 #include "runtime/vframe.inline.hpp"
93 #include "runtime/vframeArray.hpp"
94 #include "runtime/vframe_hp.hpp"
95 #include "runtime/vmThread.hpp"
96 #include "runtime/vmOperations.hpp"
97 #include "services/threadService.hpp"
98 #include "utilities/copy.hpp"
99 #include "utilities/defaultStream.hpp"
100 #include "utilities/dtrace.hpp"
101 #include "utilities/events.hpp"
102 #include "utilities/macros.hpp"
103 #include "utilities/preserveException.hpp"
104 #include "utilities/spinYield.hpp"
105 #include "utilities/vmError.hpp"
106 #if INCLUDE_JVMCI
107 #include "jvmci/jvmci.hpp"
108 #include "jvmci/jvmciEnv.hpp"
109 #endif
110 #if INCLUDE_JFR
111 #include "jfr/jfr.hpp"
112 #endif
113
114 // Set by os layer.
115 size_t JavaThread::_stack_size_at_create = 0;
116
117 #ifdef DTRACE_ENABLED
118
119 // Only bother with this argument setup if dtrace is available
120
121 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
122 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
123
124 #define DTRACE_THREAD_PROBE(probe, javathread) \
125 { \
126 ResourceMark rm(this); \
127 int len = 0; \
128 const char* name = (javathread)->name(); \
129 len = strlen(name); \
130 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
131 (char *) name, len, \
132 java_lang_Thread::thread_id((javathread)->threadObj()), \
133 (uintptr_t) (javathread)->osthread()->thread_id(), \
134 java_lang_Thread::is_daemon((javathread)->threadObj())); \
135 }
136
137 #else // ndef DTRACE_ENABLED
138
139 #define DTRACE_THREAD_PROBE(probe, javathread)
140
141 #endif // ndef DTRACE_ENABLED
142
143 void JavaThread::smr_delete() {
144 if (_on_thread_list) {
145 ThreadsSMRSupport::smr_delete(this);
146 } else {
147 delete this;
148 }
149 }
150
151 // Initialized by VMThread at vm_global_init
152 OopStorage* JavaThread::_thread_oop_storage = nullptr;
153
154 OopStorage* JavaThread::thread_oop_storage() {
155 assert(_thread_oop_storage != nullptr, "not yet initialized");
156 return _thread_oop_storage;
157 }
158
159 void JavaThread::set_threadOopHandles(oop p) {
160 assert(_thread_oop_storage != nullptr, "not yet initialized");
161 _threadObj = OopHandle(_thread_oop_storage, p);
162 _vthread = OopHandle(_thread_oop_storage, p);
163 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
164 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
165 }
166
167 oop JavaThread::threadObj() const {
168 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
169 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
170 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
171 // Instead callers must verify oop safe access.
172 return _threadObj.resolve();
173 }
174
175 oop JavaThread::vthread() const {
176 return _vthread.resolve();
177 }
178
179 void JavaThread::set_vthread(oop p) {
180 assert(_thread_oop_storage != nullptr, "not yet initialized");
181 _vthread.replace(p);
182 }
183
184 oop JavaThread::jvmti_vthread() const {
185 return _jvmti_vthread.resolve();
186 }
187
188 void JavaThread::set_jvmti_vthread(oop p) {
189 assert(_thread_oop_storage != nullptr, "not yet initialized");
190 _jvmti_vthread.replace(p);
191 }
192
193 // If there is a virtual thread mounted then return vthread() oop.
194 // Otherwise, return threadObj().
195 oop JavaThread::vthread_or_thread() const {
196 oop result = vthread();
197 if (result == nullptr) {
198 result = threadObj();
199 }
200 return result;
201 }
202
203 oop JavaThread::scopedValueCache() const {
204 return _scopedValueCache.resolve();
205 }
206
207 void JavaThread::set_scopedValueCache(oop p) {
208 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
209 _scopedValueCache.replace(p);
210 } else {
211 assert(p == nullptr, "not yet initialized");
212 }
213 }
214
215 void JavaThread::clear_scopedValueBindings() {
216 set_scopedValueCache(nullptr);
217 oop vthread_oop = vthread();
218 // vthread may be null here if we get a VM error during startup,
219 // before the java.lang.Thread instance has been created.
220 if (vthread_oop != nullptr) {
221 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
222 }
223 }
224
225 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
226 bool daemon, TRAPS) {
227 assert(thread_group.not_null(), "thread group should be specified");
228 assert(threadObj() == nullptr, "should only create Java thread object once");
229
230 InstanceKlass* ik = vmClasses::Thread_klass();
231 assert(ik->is_initialized(), "must be");
232 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
233
234 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
235 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
236 // constructor calls Thread.current(), which must be set here.
237 java_lang_Thread::set_thread(thread_oop(), this);
238 set_threadOopHandles(thread_oop());
239 // Set the lock_id to the next thread_id temporarily while initialization runs.
240 set_lock_id(ThreadIdentifier::next());
241
242 JavaValue result(T_VOID);
243 if (thread_name != nullptr) {
244 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
245 // Thread gets assigned specified name and null target
246 JavaCalls::call_special(&result,
247 thread_oop,
248 ik,
249 vmSymbols::object_initializer_name(),
250 vmSymbols::threadgroup_string_void_signature(),
251 thread_group,
252 name,
253 CHECK);
254 } else {
255 // Thread gets assigned name "Thread-nnn" and null target
256 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
257 JavaCalls::call_special(&result,
258 thread_oop,
259 ik,
260 vmSymbols::object_initializer_name(),
261 vmSymbols::threadgroup_runnable_void_signature(),
262 thread_group,
263 Handle(),
264 CHECK);
265 }
266 // Update the lock_id with the tid value.
267 set_lock_id(java_lang_Thread::thread_id(thread_oop()));
268
269 os::set_priority(this, NormPriority);
270
271 if (daemon) {
272 java_lang_Thread::set_daemon(thread_oop());
273 }
274 }
275
276 // ======= JavaThread ========
277
278 #if INCLUDE_JVMCI
279
280 jlong* JavaThread::_jvmci_old_thread_counters;
281
282 static bool jvmci_counters_include(JavaThread* thread) {
283 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
284 }
285
286 void JavaThread::collect_counters(jlong* array, int length) {
287 assert(length == JVMCICounterSize, "wrong value");
288 for (int i = 0; i < length; i++) {
289 array[i] = _jvmci_old_thread_counters[i];
290 }
291 for (JavaThread* tp : ThreadsListHandle()) {
292 if (jvmci_counters_include(tp)) {
293 for (int i = 0; i < length; i++) {
294 array[i] += tp->_jvmci_counters[i];
295 }
296 }
297 }
298 }
299
300 // Attempt to enlarge the array for per thread counters.
301 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
302 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
303 if (new_counters == nullptr) {
304 return nullptr;
305 }
306 if (old_counters == nullptr) {
307 old_counters = new_counters;
308 memset(old_counters, 0, sizeof(jlong) * new_size);
309 } else {
310 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
311 new_counters[i] = old_counters[i];
312 }
313 if (new_size > current_size) {
314 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
315 }
316 FREE_C_HEAP_ARRAY(jlong, old_counters);
317 }
318 return new_counters;
319 }
320
321 // Attempt to enlarge the array for per thread counters.
322 bool JavaThread::resize_counters(int current_size, int new_size) {
323 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
324 if (new_counters == nullptr) {
325 return false;
326 } else {
327 _jvmci_counters = new_counters;
328 return true;
329 }
330 }
331
332 class VM_JVMCIResizeCounters : public VM_Operation {
333 private:
334 int _new_size;
335 bool _failed;
336
337 public:
338 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
339 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
340 bool allow_nested_vm_operations() const { return true; }
341 void doit() {
342 // Resize the old thread counters array
343 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
344 if (new_counters == nullptr) {
345 _failed = true;
346 return;
347 } else {
348 JavaThread::_jvmci_old_thread_counters = new_counters;
349 }
350
351 // Now resize each threads array
352 for (JavaThread* tp : ThreadsListHandle()) {
353 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
354 _failed = true;
355 break;
356 }
357 }
358 if (!_failed) {
359 JVMCICounterSize = _new_size;
360 }
361 }
362
363 bool failed() { return _failed; }
364 };
365
366 bool JavaThread::resize_all_jvmci_counters(int new_size) {
367 VM_JVMCIResizeCounters op(new_size);
368 VMThread::execute(&op);
369 return !op.failed();
370 }
371
372 #endif // INCLUDE_JVMCI
373
374 #ifdef ASSERT
375 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
376 void JavaThread::check_possible_safepoint() {
377 if (_no_safepoint_count > 0) {
378 print_owned_locks();
379 assert(false, "Possible safepoint reached by thread that does not allow it");
380 }
381 #ifdef CHECK_UNHANDLED_OOPS
382 // Clear unhandled oops in JavaThreads so we get a crash right away.
383 clear_unhandled_oops();
384 #endif // CHECK_UNHANDLED_OOPS
385
386 // Macos/aarch64 should be in the right state for safepoint (e.g.
387 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
388 // happens in practice, making such issues hard to find and reproduce.
389 #if defined(__APPLE__) && defined(AARCH64)
390 if (AssertWXAtThreadSync) {
391 assert_wx_state(WXWrite);
392 }
393 #endif
394 }
395
396 void JavaThread::check_for_valid_safepoint_state() {
397 // Don't complain if running a debugging command.
398 if (DebuggingContext::is_enabled()) return;
399
400 // Check NoSafepointVerifier, which is implied by locks taken that can be
401 // shared with the VM thread. This makes sure that no locks with allow_vm_block
402 // are held.
403 check_possible_safepoint();
404
405 if (thread_state() != _thread_in_vm) {
406 fatal("LEAF method calling lock?");
407 }
408
409 if (GCALotAtAllSafepoints) {
410 // We could enter a safepoint here and thus have a gc
411 InterfaceSupport::check_gc_alot();
412 }
413 }
414 #endif // ASSERT
415
416 // A JavaThread is a normal Java thread
417
418 JavaThread::JavaThread(MemTag mem_tag) :
419 Thread(mem_tag),
420 // Initialize fields
421 _on_thread_list(false),
422 DEBUG_ONLY(_java_call_counter(0) COMMA)
423 _entry_point(nullptr),
424 _deopt_mark(nullptr),
425 _deopt_nmethod(nullptr),
426 _vframe_array_head(nullptr),
427 _vframe_array_last(nullptr),
428 _jvmti_deferred_updates(nullptr),
429 _callee_target(nullptr),
430 _vm_result(nullptr),
431 _vm_result_2(nullptr),
432
433 _current_pending_monitor(nullptr),
434 _current_pending_monitor_is_from_java(true),
435 _current_waiting_monitor(nullptr),
436 _active_handles(nullptr),
437 _free_handle_block(nullptr),
438 _lock_id(0),
439
440 _suspend_flags(0),
441
442 _thread_state(_thread_new),
443 _saved_exception_pc(nullptr),
444 #ifdef ASSERT
445 _no_safepoint_count(0),
446 _visited_for_critical_count(false),
447 #endif
448
449 _terminated(_not_terminated),
450 _in_deopt_handler(0),
451 _doing_unsafe_access(false),
452 _do_not_unlock_if_synchronized(false),
453 #if INCLUDE_JVMTI
454 _carrier_thread_suspended(false),
455 _is_in_VTMS_transition(false),
456 _is_disable_suspend(false),
457 _VTMS_transition_mark(false),
458 _on_monitor_waited_event(false),
459 _contended_entered_monitor(nullptr),
460 #ifdef ASSERT
461 _is_VTMS_transition_disabler(false),
462 #endif
463 #endif
464 _jni_attach_state(_not_attaching_via_jni),
465 _is_in_internal_oome_mark(false),
466 #if INCLUDE_JVMCI
467 _pending_deoptimization(-1),
468 _pending_monitorenter(false),
469 _pending_transfer_to_interpreter(false),
470 _pending_failed_speculation(0),
471 _jvmci{nullptr},
472 _libjvmci_runtime(nullptr),
473 _jvmci_counters(nullptr),
474 _jvmci_reserved0(0),
475 _jvmci_reserved1(0),
476 _jvmci_reserved_oop0(nullptr),
477 _live_nmethod(nullptr),
478 #endif // INCLUDE_JVMCI
479
480 _exception_oop(oop()),
481 _exception_pc(nullptr),
482 _exception_handler_pc(nullptr),
483 _is_method_handle_return(0),
484
485 _jni_active_critical(0),
486 _pending_jni_exception_check_fn(nullptr),
487 _depth_first_number(0),
488
489 // JVMTI PopFrame support
490 _popframe_condition(popframe_inactive),
491 _frames_to_pop_failed_realloc(0),
492
493 _cont_entry(nullptr),
494 _cont_fastpath(nullptr),
495 _cont_fastpath_thread_state(1),
496 _held_monitor_count(0),
497 _jni_monitor_count(0),
498 _unlocked_inflated_monitor(nullptr),
499
500 _can_call_java(true),
501
502 _preempt_alternate_return(nullptr),
503 _preemption_cancelled(false),
504 _pending_interrupted_exception(false),
505
506 _handshake(this),
507
508 _popframe_preserved_args(nullptr),
509 _popframe_preserved_args_size(0),
510
511 _jvmti_thread_state(nullptr),
512 _interp_only_mode(0),
513 _should_post_on_exceptions_flag(JNI_FALSE),
514 _thread_stat(new ThreadStatistics()),
515
516 _parker(),
517
518 _class_to_be_initialized(nullptr),
519 _class_being_initialized(nullptr),
520
521 _SleepEvent(ParkEvent::Allocate(this)),
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: " INTX_FORMAT " != " INTX_FORMAT,
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 " INTX_FORMAT " 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: " INTX_FORMAT " != " INTX_FORMAT,
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: " UINTX_FORMAT ") 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 tlab().retire();
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: " UINTX_FORMAT ").",
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 tlab().retire();
1053 }
1054
1055 Threads::remove(this, is_daemon);
1056 this->smr_delete();
1057 }
1058
1059 JavaThread* JavaThread::active() {
1060 Thread* thread = Thread::current();
1061 if (thread->is_Java_thread()) {
1062 return JavaThread::cast(thread);
1063 } else {
1064 assert(thread->is_VM_thread(), "this must be a vm thread");
1065 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1066 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1067 return ret;
1068 }
1069 }
1070
1071 bool JavaThread::is_lock_owned(address adr) const {
1072 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1073 return is_in_full_stack(adr);
1074 }
1075
1076 oop JavaThread::exception_oop() const {
1077 return Atomic::load(&_exception_oop);
1078 }
1079
1080 void JavaThread::set_exception_oop(oop o) {
1081 Atomic::store(&_exception_oop, o);
1082 }
1083
1084 void JavaThread::handle_special_runtime_exit_condition() {
1085 if (is_obj_deopt_suspend()) {
1086 frame_anchor()->make_walkable();
1087 wait_for_object_deoptimization();
1088 }
1089 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1090 }
1091
1092
1093 // Asynchronous exceptions support
1094 //
1095 void JavaThread::handle_async_exception(oop java_throwable) {
1096 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1097 assert(!is_at_poll_safepoint(), "should have never called this method");
1098
1099 if (has_last_Java_frame()) {
1100 frame f = last_frame();
1101 if (f.is_runtime_frame()) {
1102 // If the topmost frame is a runtime stub, then we are calling into
1103 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1104 // must deoptimize the caller before continuing, as the compiled exception
1105 // handler table may not be valid.
1106 RegisterMap reg_map(this,
1107 RegisterMap::UpdateMap::skip,
1108 RegisterMap::ProcessFrames::include,
1109 RegisterMap::WalkContinuation::skip);
1110 frame compiled_frame = f.sender(®_map);
1111 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1112 Deoptimization::deoptimize(this, compiled_frame);
1113 }
1114 }
1115 }
1116
1117 // We cannot call Exceptions::_throw(...) here because we cannot block
1118 set_pending_exception(java_throwable, __FILE__, __LINE__);
1119
1120 clear_scopedValueBindings();
1121
1122 LogTarget(Info, exceptions) lt;
1123 if (lt.is_enabled()) {
1124 ResourceMark rm;
1125 LogStream ls(lt);
1126 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1127 if (has_last_Java_frame()) {
1128 frame f = last_frame();
1129 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1130 }
1131 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1132 }
1133 }
1134
1135 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1136 // Do not throw asynchronous exceptions against the compiler thread
1137 // or if the thread is already exiting.
1138 if (!can_call_java() || is_exiting()) {
1139 delete aeh;
1140 return;
1141 }
1142
1143 oop exception = aeh->exception();
1144 Handshake::execute(aeh, this); // Install asynchronous handshake
1145
1146 ResourceMark rm;
1147 if (log_is_enabled(Info, exceptions)) {
1148 log_info(exceptions)("Pending Async. exception installed of type: %s",
1149 InstanceKlass::cast(exception->klass())->external_name());
1150 }
1151 // for AbortVMOnException flag
1152 Exceptions::debug_check_abort(exception->klass()->external_name());
1153
1154 oop vt_oop = vthread();
1155 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1156 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1157 java_lang_Thread::set_interrupted(threadObj(), true);
1158 this->interrupt();
1159 }
1160 }
1161
1162 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1163 AsyncExceptionHandshake* _aeh;
1164 public:
1165 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1166 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1167 ~InstallAsyncExceptionHandshake() {
1168 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1169 delete _aeh;
1170 }
1171 void do_thread(Thread* thr) {
1172 JavaThread* target = JavaThread::cast(thr);
1173 target->install_async_exception(_aeh);
1174 _aeh = nullptr;
1175 }
1176 };
1177
1178 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1179 OopHandle e(Universe::vm_global(), java_throwable);
1180 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1181 Handshake::execute(&iaeh, target);
1182 }
1183
1184 #if INCLUDE_JVMTI
1185 void JavaThread::set_is_in_VTMS_transition(bool val) {
1186 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1187 _is_in_VTMS_transition = val;
1188 }
1189
1190 #ifdef ASSERT
1191 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1192 _is_VTMS_transition_disabler = val;
1193 }
1194 #endif
1195 #endif
1196
1197 // External suspension mechanism.
1198 //
1199 // Guarantees on return (for a valid target thread):
1200 // - Target thread will not execute any new bytecode.
1201 // - Target thread will not enter any new monitors.
1202 //
1203 bool JavaThread::java_suspend() {
1204 #if INCLUDE_JVMTI
1205 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1206 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1207 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1208 #endif
1209
1210 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1211 "target JavaThread is not protected in calling context.");
1212 return this->handshake_state()->suspend();
1213 }
1214
1215 bool JavaThread::java_resume() {
1216 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1217 "missing ThreadsListHandle in calling context.");
1218 return this->handshake_state()->resume();
1219 }
1220
1221 // Wait for another thread to perform object reallocation and relocking on behalf of
1222 // this thread. The current thread is required to change to _thread_blocked in order
1223 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1224 // handshake safe, the other thread can complete the handshake used to synchronize
1225 // with this thread and then perform the reallocation and relocking.
1226 // See EscapeBarrier::sync_and_suspend_*()
1227
1228 void JavaThread::wait_for_object_deoptimization() {
1229 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1230 assert(this == Thread::current(), "invariant");
1231
1232 bool spin_wait = os::is_MP();
1233 do {
1234 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1235 // Wait for object deoptimization if requested.
1236 if (spin_wait) {
1237 // A single deoptimization is typically very short. Microbenchmarks
1238 // showed 5% better performance when spinning.
1239 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1240 SpinYield spin(spin_limit);
1241 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1242 spin.wait();
1243 }
1244 // Spin just once
1245 spin_wait = false;
1246 } else {
1247 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1248 if (is_obj_deopt_suspend()) {
1249 ml.wait();
1250 }
1251 }
1252 // A handshake for obj. deoptimization suspend could have been processed so
1253 // we must check after processing.
1254 } while (is_obj_deopt_suspend());
1255 }
1256
1257 #ifdef ASSERT
1258 // Verify the JavaThread has not yet been published in the Threads::list, and
1259 // hence doesn't need protection from concurrent access at this stage.
1260 void JavaThread::verify_not_published() {
1261 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1262 // since an unpublished JavaThread doesn't participate in the
1263 // Thread-SMR protocol for keeping a ThreadsList alive.
1264 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1265 }
1266 #endif
1267
1268 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1269 // pending, when _suspend_flags is non-zero or when we need to process a stack
1270 // watermark. Also check for pending async exceptions (except unsafe access error).
1271 // Note only the native==>Java barriers can call this function when thread state
1272 // is _thread_in_native_trans.
1273 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1274 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1275 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1276
1277 thread->set_thread_state(_thread_in_vm);
1278
1279 // Enable WXWrite: called directly from interpreter native wrapper.
1280 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1281
1282 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1283
1284 // After returning from native, it could be that the stack frames are not
1285 // yet safe to use. We catch such situations in the subsequent stack watermark
1286 // barrier, which will trap unsafe stack frames.
1287 StackWatermarkSet::before_unwind(thread);
1288 }
1289
1290 #ifndef PRODUCT
1291 // Deoptimization
1292 // Function for testing deoptimization
1293 void JavaThread::deoptimize() {
1294 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1295 bool deopt = false; // Dump stack only if a deopt actually happens.
1296 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1297 // Iterate over all frames in the thread and deoptimize
1298 for (; !fst.is_done(); fst.next()) {
1299 if (fst.current()->can_be_deoptimized()) {
1300
1301 if (only_at) {
1302 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1303 // consists of comma or carriage return separated numbers so
1304 // search for the current bci in that string.
1305 address pc = fst.current()->pc();
1306 nmethod* nm = fst.current()->cb()->as_nmethod();
1307 ScopeDesc* sd = nm->scope_desc_at(pc);
1308 char buffer[8];
1309 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1310 size_t len = strlen(buffer);
1311 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1312 while (found != nullptr) {
1313 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1314 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1315 // Check that the bci found is bracketed by terminators.
1316 break;
1317 }
1318 found = strstr(found + 1, buffer);
1319 }
1320 if (!found) {
1321 continue;
1322 }
1323 }
1324
1325 if (DebugDeoptimization && !deopt) {
1326 deopt = true; // One-time only print before deopt
1327 tty->print_cr("[BEFORE Deoptimization]");
1328 trace_frames();
1329 trace_stack();
1330 }
1331 Deoptimization::deoptimize(this, *fst.current());
1332 }
1333 }
1334
1335 if (DebugDeoptimization && deopt) {
1336 tty->print_cr("[AFTER Deoptimization]");
1337 trace_frames();
1338 }
1339 }
1340
1341
1342 // Make zombies
1343 void JavaThread::make_zombies() {
1344 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1345 if (fst.current()->can_be_deoptimized()) {
1346 // it is a Java nmethod
1347 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1348 assert(nm != nullptr, "did not find nmethod");
1349 nm->make_not_entrant();
1350 }
1351 }
1352 }
1353 #endif // PRODUCT
1354
1355
1356 void JavaThread::deoptimize_marked_methods() {
1357 if (!has_last_Java_frame()) return;
1358 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1359 for (; !fst.is_done(); fst.next()) {
1360 if (fst.current()->should_be_deoptimized()) {
1361 Deoptimization::deoptimize(this, *fst.current());
1362 }
1363 }
1364 }
1365
1366 #ifdef ASSERT
1367 void JavaThread::verify_frame_info() {
1368 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1369 (has_last_Java_frame() && java_call_counter() > 0),
1370 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1371 has_last_Java_frame() ? "true" : "false", java_call_counter());
1372 }
1373 #endif
1374
1375 // Push on a new block of JNI handles.
1376 void JavaThread::push_jni_handle_block() {
1377 // Allocate a new block for JNI handles.
1378 // Inlined code from jni_PushLocalFrame()
1379 JNIHandleBlock* old_handles = active_handles();
1380 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1381 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1382 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1383 set_active_handles(new_handles);
1384 }
1385
1386 // Pop off the current block of JNI handles.
1387 void JavaThread::pop_jni_handle_block() {
1388 // Release our JNI handle block
1389 JNIHandleBlock* old_handles = active_handles();
1390 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1391 assert(new_handles != nullptr, "should never set active handles to null");
1392 set_active_handles(new_handles);
1393 old_handles->set_pop_frame_link(nullptr);
1394 JNIHandleBlock::release_block(old_handles, this);
1395 }
1396
1397 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1398 // Verify that the deferred card marks have been flushed.
1399 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1400
1401 // Traverse the GCHandles
1402 Thread::oops_do_no_frames(f, cf);
1403
1404 if (active_handles() != nullptr) {
1405 active_handles()->oops_do(f);
1406 }
1407
1408 DEBUG_ONLY(verify_frame_info();)
1409
1410 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1411 // If we have deferred set_locals there might be oops waiting to be
1412 // written
1413 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1414 if (list != nullptr) {
1415 for (int i = 0; i < list->length(); i++) {
1416 list->at(i)->oops_do(f);
1417 }
1418 }
1419
1420 // Traverse instance variables at the end since the GC may be moving things
1421 // around using this function
1422 f->do_oop((oop*) &_vm_result);
1423 f->do_oop((oop*) &_exception_oop);
1424 #if INCLUDE_JVMCI
1425 f->do_oop((oop*) &_jvmci_reserved_oop0);
1426
1427 if (_live_nmethod != nullptr && cf != nullptr) {
1428 cf->do_nmethod(_live_nmethod);
1429 }
1430 #endif
1431
1432 if (jvmti_thread_state() != nullptr) {
1433 jvmti_thread_state()->oops_do(f, cf);
1434 }
1435
1436 // The continuation oops are really on the stack. But there is typically at most
1437 // one of those per thread, so we handle them here in the oops_do_no_frames part
1438 // so that we don't have to sprinkle as many stack watermark checks where these
1439 // oops are used. We just need to make sure the thread has started processing.
1440 ContinuationEntry* entry = _cont_entry;
1441 while (entry != nullptr) {
1442 f->do_oop((oop*)entry->cont_addr());
1443 f->do_oop((oop*)entry->chunk_addr());
1444 entry = entry->parent();
1445 }
1446
1447 if (LockingMode == LM_LIGHTWEIGHT) {
1448 lock_stack().oops_do(f);
1449 }
1450 }
1451
1452 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1453 if (!has_last_Java_frame()) {
1454 return;
1455 }
1456 // Finish any pending lazy GC activity for the frames
1457 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1458 // Traverse the execution stack
1459 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1460 fst.current()->oops_do(f, cf, fst.register_map());
1461 }
1462 }
1463
1464 #ifdef ASSERT
1465 void JavaThread::verify_states_for_handshake() {
1466 // This checks that the thread has a correct frame state during a handshake.
1467 verify_frame_info();
1468 }
1469 #endif
1470
1471 void JavaThread::nmethods_do(NMethodClosure* cf) {
1472 DEBUG_ONLY(verify_frame_info();)
1473 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1474
1475 if (has_last_Java_frame()) {
1476 // Traverse the execution stack
1477 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1478 fst.current()->nmethod_do(cf);
1479 }
1480 }
1481
1482 if (jvmti_thread_state() != nullptr) {
1483 jvmti_thread_state()->nmethods_do(cf);
1484 }
1485
1486 #if INCLUDE_JVMCI
1487 if (_live_nmethod != nullptr) {
1488 cf->do_nmethod(_live_nmethod);
1489 }
1490 #endif
1491 }
1492
1493 void JavaThread::metadata_do(MetadataClosure* f) {
1494 if (has_last_Java_frame()) {
1495 // Traverse the execution stack to call f() on the methods in the stack
1496 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1497 fst.current()->metadata_do(f);
1498 }
1499 } else if (is_Compiler_thread()) {
1500 // need to walk ciMetadata in current compile tasks to keep alive.
1501 CompilerThread* ct = (CompilerThread*)this;
1502 if (ct->env() != nullptr) {
1503 ct->env()->metadata_do(f);
1504 }
1505 CompileTask* task = ct->task();
1506 if (task != nullptr) {
1507 task->metadata_do(f);
1508 }
1509 }
1510 }
1511
1512 // Printing
1513 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1514 switch (_thread_state) {
1515 case _thread_uninitialized: return "_thread_uninitialized";
1516 case _thread_new: return "_thread_new";
1517 case _thread_new_trans: return "_thread_new_trans";
1518 case _thread_in_native: return "_thread_in_native";
1519 case _thread_in_native_trans: return "_thread_in_native_trans";
1520 case _thread_in_vm: return "_thread_in_vm";
1521 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1522 case _thread_in_Java: return "_thread_in_Java";
1523 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1524 case _thread_blocked: return "_thread_blocked";
1525 case _thread_blocked_trans: return "_thread_blocked_trans";
1526 default: return "unknown thread state";
1527 }
1528 }
1529
1530 void JavaThread::print_thread_state_on(outputStream *st) const {
1531 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1532 }
1533
1534 // Called by Threads::print() for VM_PrintThreads operation
1535 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1536 st->print_raw("\"");
1537 st->print_raw(name());
1538 st->print_raw("\" ");
1539 oop thread_oop = threadObj();
1540 if (thread_oop != nullptr) {
1541 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1542 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1543 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1544 }
1545 Thread::print_on(st, print_extended_info);
1546 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1547 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1548 if (thread_oop != nullptr) {
1549 if (is_vthread_mounted()) {
1550 // _lock_id is the thread ID of the mounted virtual thread
1551 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, lock_id());
1552 } else {
1553 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1554 }
1555 }
1556 #ifndef PRODUCT
1557 _safepoint_state->print_on(st);
1558 #endif // PRODUCT
1559 if (is_Compiler_thread()) {
1560 CompileTask *task = ((CompilerThread*)this)->task();
1561 if (task != nullptr) {
1562 st->print(" Compiling: ");
1563 task->print(st, nullptr, true, false);
1564 } else {
1565 st->print(" No compile task");
1566 }
1567 st->cr();
1568 }
1569 }
1570
1571 void JavaThread::print() const { print_on(tty); }
1572
1573 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1574 st->print("%s", get_thread_name_string(buf, buflen));
1575 }
1576
1577 // Called by fatal error handler. The difference between this and
1578 // JavaThread::print() is that we can't grab lock or allocate memory.
1579 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1580 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1581 Thread* current = Thread::current_or_null_safe();
1582 assert(current != nullptr, "cannot be called by a detached thread");
1583 st->fill_to(60);
1584 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1585 // Only access threadObj() if current thread is not a JavaThread
1586 // or if it is a JavaThread that can safely access oops.
1587 oop thread_obj = threadObj();
1588 if (thread_obj != nullptr) {
1589 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1590 }
1591 }
1592 st->print(" [");
1593 st->print("%s", _get_thread_state_name(_thread_state));
1594 if (osthread()) {
1595 st->print(", id=%d", osthread()->thread_id());
1596 }
1597 // Use raw field members for stack base/size as this could be
1598 // called before a thread has run enough to initialize them.
1599 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1600 p2i(_stack_base - _stack_size), p2i(_stack_base),
1601 PROPERFMTARGS(_stack_size));
1602 st->print("]");
1603
1604 ThreadsSMRSupport::print_info_on(this, st);
1605 return;
1606 }
1607
1608
1609 // Verification
1610
1611 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1612 // ignore if there is no stack
1613 if (!has_last_Java_frame()) return;
1614 // traverse the stack frames. Starts from top frame.
1615 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1616 frame* fr = fst.current();
1617 f(fr, fst.register_map());
1618 }
1619 }
1620
1621 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1622
1623 void JavaThread::verify() {
1624 // Verify oops in the thread.
1625 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1626
1627 // Verify the stack frames.
1628 frames_do(frame_verify);
1629 }
1630
1631 // CR 6300358 (sub-CR 2137150)
1632 // Most callers of this method assume that it can't return null but a
1633 // thread may not have a name whilst it is in the process of attaching to
1634 // the VM - see CR 6412693, and there are places where a JavaThread can be
1635 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1636 // if vm exit occurs during initialization). These cases can all be accounted
1637 // for such that this method never returns null.
1638 const char* JavaThread::name() const {
1639 if (Thread::is_JavaThread_protected(/* target */ this)) {
1640 // The target JavaThread is protected so get_thread_name_string() is safe:
1641 return get_thread_name_string();
1642 }
1643
1644 // The target JavaThread is not protected so we return the default:
1645 return Thread::name();
1646 }
1647
1648 // Like name() but doesn't include the protection check. This must only be
1649 // called when it is known to be safe, even though the protection check can't tell
1650 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1651 const char* JavaThread::name_raw() const {
1652 return get_thread_name_string();
1653 }
1654
1655 // Returns a non-null representation of this thread's name, or a suitable
1656 // descriptive string if there is no set name.
1657 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1658 const char* name_str;
1659 #ifdef ASSERT
1660 Thread* current = Thread::current_or_null_safe();
1661 assert(current != nullptr, "cannot be called by a detached thread");
1662 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1663 // Only access threadObj() if current thread is not a JavaThread
1664 // or if it is a JavaThread that can safely access oops.
1665 #endif
1666 oop thread_obj = threadObj();
1667 if (thread_obj != nullptr) {
1668 oop name = java_lang_Thread::name(thread_obj);
1669 if (name != nullptr) {
1670 if (buf == nullptr) {
1671 name_str = java_lang_String::as_utf8_string(name);
1672 } else {
1673 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1674 }
1675 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1676 name_str = "<no-name - thread is attaching>";
1677 } else {
1678 name_str = "<un-named>";
1679 }
1680 } else {
1681 name_str = Thread::name();
1682 }
1683 #ifdef ASSERT
1684 } else {
1685 // Current JavaThread has exited...
1686 if (current == this) {
1687 // ... and is asking about itself:
1688 name_str = "<no-name - current JavaThread has exited>";
1689 } else {
1690 // ... and it can't safely determine this JavaThread's name so
1691 // use the default thread name.
1692 name_str = Thread::name();
1693 }
1694 }
1695 #endif
1696 assert(name_str != nullptr, "unexpected null thread name");
1697 return name_str;
1698 }
1699
1700 // Helper to extract the name from the thread oop for logging.
1701 const char* JavaThread::name_for(oop thread_obj) {
1702 assert(thread_obj != nullptr, "precondition");
1703 oop name = java_lang_Thread::name(thread_obj);
1704 const char* name_str;
1705 if (name != nullptr) {
1706 name_str = java_lang_String::as_utf8_string(name);
1707 } else {
1708 name_str = "<un-named>";
1709 }
1710 return name_str;
1711 }
1712
1713 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1714
1715 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1716 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1717 // Link Java Thread object <-> C++ Thread
1718
1719 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1720 // and put it into a new Handle. The Handle "thread_oop" can then
1721 // be used to pass the C++ thread object to other methods.
1722
1723 // Set the Java level thread object (jthread) field of the
1724 // new thread (a JavaThread *) to C++ thread object using the
1725 // "thread_oop" handle.
1726
1727 // Set the thread field (a JavaThread *) of the
1728 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1729
1730 Handle thread_oop(Thread::current(),
1731 JNIHandles::resolve_non_null(jni_thread));
1732 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1733 "must be initialized");
1734 set_threadOopHandles(thread_oop());
1735 set_lock_id(java_lang_Thread::thread_id(thread_oop()));
1736
1737 if (prio == NoPriority) {
1738 prio = java_lang_Thread::priority(thread_oop());
1739 assert(prio != NoPriority, "A valid priority should be present");
1740 }
1741
1742 // Push the Java priority down to the native thread; needs Threads_lock
1743 Thread::set_priority(this, prio);
1744
1745 // Add the new thread to the Threads list and set it in motion.
1746 // We must have threads lock in order to call Threads::add.
1747 // It is crucial that we do not block before the thread is
1748 // added to the Threads list for if a GC happens, then the java_thread oop
1749 // will not be visited by GC.
1750 Threads::add(this);
1751 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1752 // on a ThreadsList. We don't want to wait for the release when the
1753 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1754 // is already visible to JVM/TI via the ThreadsList.
1755 java_lang_Thread::release_set_thread(thread_oop(), this);
1756 }
1757
1758 oop JavaThread::current_park_blocker() {
1759 // Support for JSR-166 locks
1760 oop thread_oop = threadObj();
1761 if (thread_oop != nullptr) {
1762 return java_lang_Thread::park_blocker(thread_oop);
1763 }
1764 return nullptr;
1765 }
1766
1767 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1768 // This is the external format, selecting the platform or vthread
1769 // as applicable, and allowing for a native-only stack.
1770 void JavaThread::print_jni_stack() {
1771 assert(this == JavaThread::current(), "Can't print stack of other threads");
1772 if (!has_last_Java_frame()) {
1773 print_native_stack_on(tty);
1774 } else {
1775 print_active_stack_on(tty);
1776 }
1777 }
1778
1779 void JavaThread::print_native_stack_on(outputStream *st) {
1780 assert(this == JavaThread::current(), "Can't print stack of other threads");
1781 ResourceMark rm;
1782 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1783 if (buf == nullptr) {
1784 st->print_cr("Unable to print native stack - out of memory");
1785 return;
1786 }
1787 address lastpc = nullptr;
1788 if (os::platform_print_native_stack(st, nullptr, buf, O_BUFLEN, lastpc)) {
1789 // We have printed the native stack in platform-specific code,
1790 // so nothing else to do in this case.
1791 } else {
1792 frame f = os::current_frame();
1793 VMError::print_native_stack(st, f, this, true /*print_source_info */,
1794 -1 /* max stack */, buf, O_BUFLEN);
1795 }
1796 }
1797
1798 void JavaThread::print_stack_on(outputStream* st) {
1799 if (!has_last_Java_frame()) return;
1800
1801 Thread* current_thread = Thread::current();
1802 ResourceMark rm(current_thread);
1803 HandleMark hm(current_thread);
1804
1805 RegisterMap reg_map(this,
1806 RegisterMap::UpdateMap::include,
1807 RegisterMap::ProcessFrames::include,
1808 RegisterMap::WalkContinuation::skip);
1809 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1810 int count = 0;
1811 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1812 if (f->is_java_frame()) {
1813 javaVFrame* jvf = javaVFrame::cast(f);
1814 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1815
1816 // Print out lock information
1817 if (JavaMonitorsInStackTrace) {
1818 jvf->print_lock_info_on(st, count);
1819 }
1820 } else {
1821 // Ignore non-Java frames
1822 }
1823
1824 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1825 count++;
1826 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1827 }
1828 }
1829
1830 void JavaThread::print_vthread_stack_on(outputStream* st) {
1831 assert(is_vthread_mounted(), "Caller should have checked this");
1832 assert(has_last_Java_frame(), "must be");
1833
1834 Thread* current_thread = Thread::current();
1835 ResourceMark rm(current_thread);
1836 HandleMark hm(current_thread);
1837
1838 RegisterMap reg_map(this,
1839 RegisterMap::UpdateMap::include,
1840 RegisterMap::ProcessFrames::include,
1841 RegisterMap::WalkContinuation::include);
1842 ContinuationEntry* cont_entry = last_continuation();
1843 vframe* start_vf = last_java_vframe(®_map);
1844 int count = 0;
1845 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1846 // Watch for end of vthread stack
1847 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1848 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1849 if (cont_entry->is_virtual_thread()) {
1850 break;
1851 }
1852 cont_entry = cont_entry->parent();
1853 }
1854 if (f->is_java_frame()) {
1855 javaVFrame* jvf = javaVFrame::cast(f);
1856 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1857
1858 // Print out lock information
1859 if (JavaMonitorsInStackTrace) {
1860 jvf->print_lock_info_on(st, count);
1861 }
1862 } else {
1863 // Ignore non-Java frames
1864 }
1865
1866 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1867 count++;
1868 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1869 }
1870 }
1871
1872 void JavaThread::print_active_stack_on(outputStream* st) {
1873 if (is_vthread_mounted()) {
1874 print_vthread_stack_on(st);
1875 } else {
1876 print_stack_on(st);
1877 }
1878 }
1879
1880 #if INCLUDE_JVMTI
1881 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1882 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1883 set_jvmti_vthread(thread_oop);
1884
1885 // unbind current JvmtiThreadState from JavaThread
1886 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1887
1888 // bind new JvmtiThreadState to JavaThread
1889 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1890
1891 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1892 JvmtiThreadState::process_pending_interp_only(this);
1893
1894 return jvmti_thread_state();
1895 }
1896 #endif
1897
1898 // JVMTI PopFrame support
1899 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1900 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1901 if (in_bytes(size_in_bytes) != 0) {
1902 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1903 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1904 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1905 }
1906 }
1907
1908 void* JavaThread::popframe_preserved_args() {
1909 return _popframe_preserved_args;
1910 }
1911
1912 ByteSize JavaThread::popframe_preserved_args_size() {
1913 return in_ByteSize(_popframe_preserved_args_size);
1914 }
1915
1916 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1917 int sz = in_bytes(popframe_preserved_args_size());
1918 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1919 return in_WordSize(sz / wordSize);
1920 }
1921
1922 void JavaThread::popframe_free_preserved_args() {
1923 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1924 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1925 _popframe_preserved_args = nullptr;
1926 _popframe_preserved_args_size = 0;
1927 }
1928
1929 #ifndef PRODUCT
1930
1931 void JavaThread::trace_frames() {
1932 tty->print_cr("[Describe stack]");
1933 int frame_no = 1;
1934 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1935 tty->print(" %d. ", frame_no++);
1936 fst.current()->print_value_on(tty);
1937 tty->cr();
1938 }
1939 }
1940
1941 class PrintAndVerifyOopClosure: public OopClosure {
1942 protected:
1943 template <class T> inline void do_oop_work(T* p) {
1944 oop obj = RawAccess<>::oop_load(p);
1945 if (obj == nullptr) return;
1946 tty->print(INTPTR_FORMAT ": ", p2i(p));
1947 if (oopDesc::is_oop_or_null(obj)) {
1948 if (obj->is_objArray()) {
1949 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1950 } else {
1951 obj->print();
1952 }
1953 } else {
1954 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1955 }
1956 tty->cr();
1957 }
1958 public:
1959 virtual void do_oop(oop* p) { do_oop_work(p); }
1960 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1961 };
1962
1963 #ifdef ASSERT
1964 // Print or validate the layout of stack frames
1965 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1966 ResourceMark rm;
1967 PreserveExceptionMark pm(this);
1968 FrameValues values;
1969 int frame_no = 0;
1970 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1971 fst.current()->describe(values, ++frame_no, fst.register_map());
1972 if (depth == frame_no) break;
1973 }
1974 Continuation::describe(values);
1975 if (validate_only) {
1976 values.validate();
1977 } else {
1978 tty->print_cr("[Describe stack layout]");
1979 values.print(this);
1980 }
1981 }
1982 #endif
1983
1984 void JavaThread::trace_stack_from(vframe* start_vf) {
1985 ResourceMark rm;
1986 int vframe_no = 1;
1987 for (vframe* f = start_vf; f; f = f->sender()) {
1988 if (f->is_java_frame()) {
1989 javaVFrame::cast(f)->print_activation(vframe_no++);
1990 } else {
1991 f->print();
1992 }
1993 if (vframe_no > StackPrintLimit) {
1994 tty->print_cr("...<more frames>...");
1995 return;
1996 }
1997 }
1998 }
1999
2000
2001 void JavaThread::trace_stack() {
2002 if (!has_last_Java_frame()) return;
2003 Thread* current_thread = Thread::current();
2004 ResourceMark rm(current_thread);
2005 HandleMark hm(current_thread);
2006 RegisterMap reg_map(this,
2007 RegisterMap::UpdateMap::include,
2008 RegisterMap::ProcessFrames::include,
2009 RegisterMap::WalkContinuation::skip);
2010 trace_stack_from(last_java_vframe(®_map));
2011 }
2012
2013
2014 #endif // PRODUCT
2015
2016 // Slow-path increment of the held monitor counts. JNI locking is always
2017 // this slow-path.
2018 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2019 #ifdef SUPPORT_MONITOR_COUNT
2020
2021 if (LockingMode != LM_LEGACY) {
2022 // Nothing to do. Just do some sanity check.
2023 assert(_held_monitor_count == 0, "counter should not be used");
2024 assert(_jni_monitor_count == 0, "counter should not be used");
2025 return;
2026 }
2027
2028 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
2029 _held_monitor_count += i;
2030 if (jni) {
2031 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
2032 _jni_monitor_count += i;
2033 }
2034 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2035 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2036 #endif // SUPPORT_MONITOR_COUNT
2037 }
2038
2039 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2040 // this slow-path.
2041 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2042 #ifdef SUPPORT_MONITOR_COUNT
2043
2044 if (LockingMode != LM_LEGACY) {
2045 // Nothing to do. Just do some sanity check.
2046 assert(_held_monitor_count == 0, "counter should not be used");
2047 assert(_jni_monitor_count == 0, "counter should not be used");
2048 return;
2049 }
2050
2051 _held_monitor_count -= i;
2052 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
2053 if (jni) {
2054 _jni_monitor_count -= i;
2055 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
2056 }
2057 // When a thread is detaching with still owned JNI monitors, the logic that releases
2058 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2059 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2060 // JNI count is directly set to zero.
2061 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2062 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2063 #endif // SUPPORT_MONITOR_COUNT
2064 }
2065
2066 frame JavaThread::vthread_last_frame() {
2067 assert (is_vthread_mounted(), "Virtual thread not mounted");
2068 return last_frame();
2069 }
2070
2071 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2072 const ContinuationEntry* entry = vthread_continuation();
2073 guarantee (entry != nullptr, "Not a carrier thread");
2074 frame f = entry->to_frame();
2075 if (reg_map->process_frames()) {
2076 entry->flush_stack_processing(this);
2077 }
2078 entry->update_register_map(reg_map);
2079 return f.sender(reg_map);
2080 }
2081
2082 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2083 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2084 }
2085
2086 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2087 assert(reg_map != nullptr, "a map must be given");
2088 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2089 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2090 }
2091 return nullptr;
2092 }
2093
2094 Klass* JavaThread::security_get_caller_class(int depth) {
2095 ResetNoHandleMark rnhm;
2096 HandleMark hm(Thread::current());
2097
2098 vframeStream vfst(this);
2099 vfst.security_get_caller_frame(depth);
2100 if (!vfst.at_end()) {
2101 return vfst.method()->method_holder();
2102 }
2103 return nullptr;
2104 }
2105
2106 // Internal convenience function for millisecond resolution sleeps.
2107 bool JavaThread::sleep(jlong millis) {
2108 jlong nanos;
2109 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2110 // Conversion to nanos would overflow, saturate at max
2111 nanos = max_jlong;
2112 } else {
2113 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2114 }
2115 return sleep_nanos(nanos);
2116 }
2117
2118 // java.lang.Thread.sleep support
2119 // Returns true if sleep time elapsed as expected, and false
2120 // if the thread was interrupted.
2121 bool JavaThread::sleep_nanos(jlong nanos) {
2122 assert(this == Thread::current(), "thread consistency check");
2123 assert(nanos >= 0, "nanos are in range");
2124
2125 ParkEvent * const slp = this->_SleepEvent;
2126 // Because there can be races with thread interruption sending an unpark()
2127 // to the event, we explicitly reset it here to avoid an immediate return.
2128 // The actual interrupt state will be checked before we park().
2129 slp->reset();
2130 // Thread interruption establishes a happens-before ordering in the
2131 // Java Memory Model, so we need to ensure we synchronize with the
2132 // interrupt state.
2133 OrderAccess::fence();
2134
2135 jlong prevtime = os::javaTimeNanos();
2136
2137 jlong nanos_remaining = nanos;
2138
2139 for (;;) {
2140 // interruption has precedence over timing out
2141 if (this->is_interrupted(true)) {
2142 return false;
2143 }
2144
2145 if (nanos_remaining <= 0) {
2146 return true;
2147 }
2148
2149 {
2150 ThreadBlockInVM tbivm(this);
2151 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2152 slp->park_nanos(nanos_remaining);
2153 }
2154
2155 // Update elapsed time tracking
2156 jlong newtime = os::javaTimeNanos();
2157 if (newtime - prevtime < 0) {
2158 // time moving backwards, should only happen if no monotonic clock
2159 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2160 assert(false,
2161 "unexpected time moving backwards detected in JavaThread::sleep()");
2162 } else {
2163 nanos_remaining -= (newtime - prevtime);
2164 }
2165 prevtime = newtime;
2166 }
2167 }
2168
2169 // Last thread running calls java.lang.Shutdown.shutdown()
2170 void JavaThread::invoke_shutdown_hooks() {
2171 HandleMark hm(this);
2172
2173 // We could get here with a pending exception, if so clear it now.
2174 if (this->has_pending_exception()) {
2175 this->clear_pending_exception();
2176 }
2177
2178 EXCEPTION_MARK;
2179 Klass* shutdown_klass =
2180 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2181 THREAD);
2182 if (shutdown_klass != nullptr) {
2183 // SystemDictionary::resolve_or_null will return null if there was
2184 // an exception. If we cannot load the Shutdown class, just don't
2185 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2186 // won't be run. Note that if a shutdown hook was registered,
2187 // the Shutdown class would have already been loaded
2188 // (Runtime.addShutdownHook will load it).
2189 JavaValue result(T_VOID);
2190 JavaCalls::call_static(&result,
2191 shutdown_klass,
2192 vmSymbols::shutdown_name(),
2193 vmSymbols::void_method_signature(),
2194 THREAD);
2195 }
2196 CLEAR_PENDING_EXCEPTION;
2197 }
2198
2199 #ifndef PRODUCT
2200 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2201 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2202 }
2203 #endif
2204
2205 // Helper function to create the java.lang.Thread object for a
2206 // VM-internal thread. The thread will have the given name, and be
2207 // a member of the "system" ThreadGroup.
2208 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2209 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2210
2211 // Initialize thread_oop to put it into the system threadGroup.
2212 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2213 Handle thread_group(THREAD, Universe::system_thread_group());
2214 Handle thread_oop =
2215 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2216 vmSymbols::threadgroup_string_void_signature(),
2217 thread_group,
2218 string,
2219 CHECK_NH);
2220
2221 return thread_oop;
2222 }
2223
2224 // Starts the target JavaThread as a daemon of the given priority, and
2225 // bound to the given java.lang.Thread instance.
2226 // The Threads_lock is held for the duration.
2227 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2228 Handle thread_oop, ThreadPriority prio) {
2229
2230 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2231
2232 MutexLocker mu(current, Threads_lock);
2233
2234 // Initialize the fields of the thread_oop first.
2235 if (prio != NoPriority) {
2236 java_lang_Thread::set_priority(thread_oop(), prio);
2237 // Note: we don't call os::set_priority here. Possibly we should,
2238 // else all threads should call it themselves when they first run.
2239 }
2240
2241 java_lang_Thread::set_daemon(thread_oop());
2242
2243 // Now bind the thread_oop to the target JavaThread.
2244 target->set_threadOopHandles(thread_oop());
2245 target->set_lock_id(java_lang_Thread::thread_id(thread_oop()));
2246
2247 Threads::add(target); // target is now visible for safepoint/handshake
2248 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2249 // on a ThreadsList. We don't want to wait for the release when the
2250 // Theads_lock is dropped when the 'mu' destructor is run since the
2251 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2252
2253 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2254 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2255 Thread::start(target);
2256 }
2257
2258 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2259 // At this point it may be possible that no osthread was created for the
2260 // JavaThread due to lack of resources. However, since this must work
2261 // for critical system threads just check and abort if this fails.
2262 if (thread->osthread() == nullptr) {
2263 // This isn't really an OOM condition, but historically this is what
2264 // we report.
2265 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2266 os::native_thread_creation_failed_msg());
2267 }
2268 }
2269
2270 void JavaThread::pretouch_stack() {
2271 // Given an established java thread stack with usable area followed by
2272 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2273 // from the current frame down to the start of the shadow zone.
2274 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2275 if (is_in_full_stack(end)) {
2276 char* p1 = (char*) alloca(1);
2277 address here = (address) &p1;
2278 if (is_in_full_stack(here) && here > end) {
2279 size_t to_alloc = here - end;
2280 char* p2 = (char*) alloca(to_alloc);
2281 log_trace(os, thread)("Pretouching thread stack for " UINTX_FORMAT ": " RANGEFMT ".",
2282 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2283 os::pretouch_memory(p2, p2 + to_alloc,
2284 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2285 }
2286 }
2287 }
2288
2289 // Deferred OopHandle release support.
2290
2291 class OopHandleList : public CHeapObj<mtInternal> {
2292 static const int _count = 4;
2293 OopHandle _handles[_count];
2294 OopHandleList* _next;
2295 int _index;
2296 public:
2297 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2298 void add(OopHandle h) {
2299 assert(_index < _count, "too many additions");
2300 _handles[_index++] = h;
2301 }
2302 ~OopHandleList() {
2303 assert(_index == _count, "usage error");
2304 for (int i = 0; i < _index; i++) {
2305 _handles[i].release(JavaThread::thread_oop_storage());
2306 }
2307 }
2308 OopHandleList* next() const { return _next; }
2309 };
2310
2311 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2312
2313 // Called by the ServiceThread to do the work of releasing
2314 // the OopHandles.
2315 void JavaThread::release_oop_handles() {
2316 OopHandleList* list;
2317 {
2318 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2319 list = _oop_handle_list;
2320 _oop_handle_list = nullptr;
2321 }
2322 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2323
2324 while (list != nullptr) {
2325 OopHandleList* l = list;
2326 list = l->next();
2327 delete l;
2328 }
2329 }
2330
2331 // Add our OopHandles for later release.
2332 void JavaThread::add_oop_handles_for_release() {
2333 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2334 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2335 new_head->add(_threadObj);
2336 new_head->add(_vthread);
2337 new_head->add(_jvmti_vthread);
2338 new_head->add(_scopedValueCache);
2339 _oop_handle_list = new_head;
2340 Service_lock->notify_all();
2341 }
2342
2343 #if INCLUDE_JFR
2344 void JavaThread::set_last_freeze_fail_result(freeze_result result) {
2345 assert(result != freeze_ok, "sanity check");
2346 _last_freeze_fail_result = result;
2347 _last_freeze_fail_time = Ticks::now();
2348 }
2349
2350 // Post jdk.VirtualThreadPinned event
2351 void JavaThread::post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) {
2352 assert(result != freeze_ok, "sanity check");
2353 if (event->should_commit()) {
2354 char reason[256];
2355 if (class_to_be_initialized() != nullptr) {
2356 ResourceMark rm(this);
2357 jio_snprintf(reason, sizeof reason, "Waited for initialization of %s by another thread",
2358 class_to_be_initialized()->external_name());
2359 event->set_pinnedReason(reason);
2360 } else if (class_being_initialized() != nullptr) {
2361 ResourceMark rm(this);
2362 jio_snprintf(reason, sizeof(reason), "VM call to %s.<clinit> on stack",
2363 class_being_initialized()->external_name());
2364 event->set_pinnedReason(reason);
2365 } else if (result == freeze_pinned_native) {
2366 event->set_pinnedReason("Native or VM frame on stack");
2367 } else {
2368 jio_snprintf(reason, sizeof(reason), "Freeze or preempt failed (%d)", result);
2369 event->set_pinnedReason(reason);
2370 }
2371 event->set_blockingOperation(op);
2372 event->set_carrierThread(JFR_JVM_THREAD_ID(this));
2373 event->commit();
2374 }
2375 }
2376 #endif