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_in_tmp_VTMS_transition(false),
457 _is_disable_suspend(false),
458 _VTMS_transition_mark(false),
459 _pending_jvmti_unmount_event(false),
460 _on_monitor_waited_event(false),
461 _contended_entered_monitor(nullptr),
462 #ifdef ASSERT
463 _is_VTMS_transition_disabler(false),
464 #endif
465 #endif
466 _jni_attach_state(_not_attaching_via_jni),
467 _is_in_internal_oome_mark(false),
468 #if INCLUDE_JVMCI
469 _pending_deoptimization(-1),
470 _pending_monitorenter(false),
471 _pending_transfer_to_interpreter(false),
472 _pending_failed_speculation(0),
473 _jvmci{nullptr},
474 _libjvmci_runtime(nullptr),
475 _jvmci_counters(nullptr),
476 _jvmci_reserved0(0),
477 _jvmci_reserved1(0),
478 _jvmci_reserved_oop0(nullptr),
479 _live_nmethod(nullptr),
480 #endif // INCLUDE_JVMCI
481
482 _exception_oop(oop()),
483 _exception_pc(nullptr),
484 _exception_handler_pc(nullptr),
485 _is_method_handle_return(0),
486
487 _jni_active_critical(0),
488 _pending_jni_exception_check_fn(nullptr),
489 _depth_first_number(0),
490
491 // JVMTI PopFrame support
492 _popframe_condition(popframe_inactive),
493 _frames_to_pop_failed_realloc(0),
494
495 _cont_entry(nullptr),
496 _cont_fastpath(nullptr),
497 _cont_fastpath_thread_state(1),
498 _held_monitor_count(0),
499 _jni_monitor_count(0),
500 _unlocked_inflated_monitor(nullptr),
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
520 _SleepEvent(ParkEvent::Allocate(this)),
521
522 _lock_stack(this),
523 _om_cache(this) {
524 set_jni_functions(jni_functions());
525
526 #if INCLUDE_JVMCI
527 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
528 if (JVMCICounterSize > 0) {
529 resize_counters(0, (int) JVMCICounterSize);
530 }
531 #endif // INCLUDE_JVMCI
532
533 // Setup safepoint state info for this thread
534 ThreadSafepointState::create(this);
535
536 SafepointMechanism::initialize_header(this);
537
538 set_requires_cross_modify_fence(false);
539
540 pd_initialize();
541 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
542 }
543
544 JavaThread* JavaThread::create_attaching_thread() {
545 JavaThread* jt = new JavaThread();
546 jt->_jni_attach_state = _attaching_via_jni;
547 return jt;
548 }
549
550 // interrupt support
551
552 void JavaThread::interrupt() {
553 // All callers should have 'this' thread protected by a
554 // ThreadsListHandle so that it cannot terminate and deallocate
555 // itself.
556 debug_only(check_for_dangling_thread_pointer(this);)
557
558 // For Windows _interrupt_event
559 WINDOWS_ONLY(osthread()->set_interrupted(true);)
560
561 // For Thread.sleep
562 _SleepEvent->unpark();
563
564 // For JSR166 LockSupport.park
565 parker()->unpark();
566
567 // For ObjectMonitor and JvmtiRawMonitor
568 _ParkEvent->unpark();
569 }
570
571 bool JavaThread::is_interrupted(bool clear_interrupted) {
572 debug_only(check_for_dangling_thread_pointer(this);)
573
574 if (_threadObj.peek() == nullptr) {
575 // If there is no j.l.Thread then it is impossible to have
576 // been interrupted. We can find null during VM initialization
577 // or when a JNI thread is still in the process of attaching.
578 // In such cases this must be the current thread.
579 assert(this == Thread::current(), "invariant");
580 return false;
581 }
582
583 bool interrupted = java_lang_Thread::interrupted(threadObj());
584
585 // NOTE that since there is no "lock" around the interrupt and
586 // is_interrupted operations, there is the possibility that the
587 // interrupted flag will be "false" but that the
588 // low-level events will be in the signaled state. This is
589 // intentional. The effect of this is that Object.wait() and
590 // LockSupport.park() will appear to have a spurious wakeup, which
591 // is allowed and not harmful, and the possibility is so rare that
592 // it is not worth the added complexity to add yet another lock.
593 // For the sleep event an explicit reset is performed on entry
594 // to JavaThread::sleep, so there is no early return. It has also been
595 // recommended not to put the interrupted flag into the "event"
596 // structure because it hides the issue.
597 // Also, because there is no lock, we must only clear the interrupt
598 // state if we are going to report that we were interrupted; otherwise
599 // an interrupt that happens just after we read the field would be lost.
600 if (interrupted && clear_interrupted) {
601 assert(this == Thread::current(), "only the current thread can clear");
602 java_lang_Thread::set_interrupted(threadObj(), false);
603 WINDOWS_ONLY(osthread()->set_interrupted(false);)
604 }
605 return interrupted;
606 }
607
608 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
609 // the Java code in Object::wait which are not present in RawMonitorWait.
610 bool JavaThread::get_and_clear_interrupted() {
611 if (!is_interrupted(false)) {
612 return false;
613 }
614 oop thread_oop = vthread_or_thread();
615 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
616
617 if (!is_virtual) {
618 return is_interrupted(true);
619 }
620 // Virtual thread: clear interrupt status for both virtual and
621 // carrier threads under the interruptLock protection.
622 JavaThread* current = JavaThread::current();
623 HandleMark hm(current);
624 Handle thread_h(current, thread_oop);
625 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
626
627 // re-check the interrupt status under the interruptLock protection
628 bool interrupted = java_lang_Thread::interrupted(thread_h());
629
630 if (interrupted) {
631 assert(this == Thread::current(), "only the current thread can clear");
632 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
633 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
634 WINDOWS_ONLY(osthread()->set_interrupted(false);)
635 }
636 return interrupted;
637 }
638
639 void JavaThread::block_if_vm_exited() {
640 if (_terminated == _vm_exited) {
641 // _vm_exited is set at safepoint, and Threads_lock is never released
642 // so we will block here forever.
643 // Here we can be doing a jump from a safe state to an unsafe state without
644 // proper transition, but it happens after the final safepoint has begun so
645 // this jump won't cause any safepoint problems.
646 set_thread_state(_thread_in_vm);
647 Threads_lock->lock();
648 ShouldNotReachHere();
649 }
650 }
651
652 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
653 set_entry_point(entry_point);
654 // Create the native thread itself.
655 // %note runtime_23
656 os::ThreadType thr_type = os::java_thread;
657 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
658 os::java_thread;
659 os::create_thread(this, thr_type, stack_sz);
660 // The _osthread may be null here because we ran out of memory (too many threads active).
661 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
662 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
663 // the exception consists of creating the exception object & initializing it, initialization
664 // will leave the VM via a JavaCall and then all locks must be unlocked).
665 //
666 // The thread is still suspended when we reach here. Thread must be explicit started
667 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
668 // by calling Threads:add. The reason why this is not done here, is because the thread
669 // object must be fully initialized (take a look at JVM_Start)
670 }
671
672 JavaThread::~JavaThread() {
673
674 // Enqueue OopHandles for release by the service thread.
675 add_oop_handles_for_release();
676
677 // Return the sleep event to the free list
678 ParkEvent::Release(_SleepEvent);
679 _SleepEvent = nullptr;
680
681 // Free any remaining previous UnrollBlock
682 vframeArray* old_array = vframe_array_last();
683
684 if (old_array != nullptr) {
685 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
686 old_array->set_unroll_block(nullptr);
687 delete old_info;
688 delete old_array;
689 }
690
691 JvmtiDeferredUpdates* updates = deferred_updates();
692 if (updates != nullptr) {
693 // This can only happen if thread is destroyed before deoptimization occurs.
694 assert(updates->count() > 0, "Updates holder not deleted");
695 // free deferred updates.
696 delete updates;
697 set_deferred_updates(nullptr);
698 }
699
700 // All Java related clean up happens in exit
701 ThreadSafepointState::destroy(this);
702 if (_thread_stat != nullptr) delete _thread_stat;
703
704 #if INCLUDE_JVMCI
705 if (JVMCICounterSize > 0) {
706 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
707 }
708 #endif // INCLUDE_JVMCI
709 }
710
711
712 // First JavaThread specific code executed by a new Java thread.
713 void JavaThread::pre_run() {
714 // empty - see comments in run()
715 }
716
717 // The main routine called by a new Java thread. This isn't overridden
718 // by subclasses, instead different subclasses define a different "entry_point"
719 // which defines the actual logic for that kind of thread.
720 void JavaThread::run() {
721 // initialize thread-local alloc buffer related fields
722 initialize_tlab();
723
724 _stack_overflow_state.create_stack_guard_pages();
725
726 cache_global_variables();
727
728 // Thread is now sufficiently initialized to be handled by the safepoint code as being
729 // in the VM. Change thread state from _thread_new to _thread_in_vm
730 assert(this->thread_state() == _thread_new, "wrong thread state");
731 set_thread_state(_thread_in_vm);
732
733 // Before a thread is on the threads list it is always safe, so after leaving the
734 // _thread_new we should emit a instruction barrier. The distance to modified code
735 // from here is probably far enough, but this is consistent and safe.
736 OrderAccess::cross_modify_fence();
737
738 assert(JavaThread::current() == this, "sanity check");
739 assert(!Thread::current()->owns_locks(), "sanity check");
740
741 DTRACE_THREAD_PROBE(start, this);
742
743 // This operation might block. We call that after all safepoint checks for a new thread has
744 // been completed.
745 set_active_handles(JNIHandleBlock::allocate_block());
746
747 if (JvmtiExport::should_post_thread_life()) {
748 JvmtiExport::post_thread_start(this);
749
750 }
751
752 if (AlwaysPreTouchStacks) {
753 pretouch_stack();
754 }
755
756 // We call another function to do the rest so we are sure that the stack addresses used
757 // from there will be lower than the stack base just computed.
758 thread_main_inner();
759 }
760
761 void JavaThread::thread_main_inner() {
762 assert(JavaThread::current() == this, "sanity check");
763 assert(_threadObj.peek() != nullptr, "just checking");
764
765 // Execute thread entry point unless this thread has a pending exception.
766 // Note: Due to JVMTI StopThread we can have pending exceptions already!
767 if (!this->has_pending_exception()) {
768 {
769 ResourceMark rm(this);
770 this->set_native_thread_name(this->name());
771 }
772 HandleMark hm(this);
773 this->entry_point()(this, this);
774 }
775
776 DTRACE_THREAD_PROBE(stop, this);
777
778 // Cleanup is handled in post_run()
779 }
780
781 // Shared teardown for all JavaThreads
782 void JavaThread::post_run() {
783 this->exit(false);
784 this->unregister_thread_stack_with_NMT();
785 // Defer deletion to here to ensure 'this' is still referenceable in call_run
786 // for any shared tear-down.
787 this->smr_delete();
788 }
789
790 static void ensure_join(JavaThread* thread) {
791 // We do not need to grab the Threads_lock, since we are operating on ourself.
792 Handle threadObj(thread, thread->threadObj());
793 assert(threadObj.not_null(), "java thread object must exist");
794 ObjectLocker lock(threadObj, thread);
795 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
796 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
797 // Clear the native thread instance - this makes isAlive return false and allows the join()
798 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
799 // requirements.
800 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
801 java_lang_Thread::release_set_thread(threadObj(), nullptr);
802 lock.notify_all(thread);
803 // Ignore pending exception, since we are exiting anyway
804 thread->clear_pending_exception();
805 }
806
807 static bool is_daemon(oop threadObj) {
808 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
809 }
810
811 // For any new cleanup additions, please check to see if they need to be applied to
812 // cleanup_failed_attach_current_thread as well.
813 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
814 assert(this == JavaThread::current(), "thread consistency check");
815 assert(!is_exiting(), "should not be exiting or terminated already");
816
817 elapsedTimer _timer_exit_phase1;
818 elapsedTimer _timer_exit_phase2;
819 elapsedTimer _timer_exit_phase3;
820 elapsedTimer _timer_exit_phase4;
821
822 om_clear_monitor_cache();
823
824 if (log_is_enabled(Debug, os, thread, timer)) {
825 _timer_exit_phase1.start();
826 }
827
828 HandleMark hm(this);
829 Handle uncaught_exception(this, this->pending_exception());
830 this->clear_pending_exception();
831 Handle threadObj(this, this->threadObj());
832 assert(threadObj.not_null(), "Java thread object should be created");
833
834 if (!destroy_vm) {
835 if (uncaught_exception.not_null()) {
836 EXCEPTION_MARK;
837 // Call method Thread.dispatchUncaughtException().
838 Klass* thread_klass = vmClasses::Thread_klass();
839 JavaValue result(T_VOID);
840 JavaCalls::call_virtual(&result,
841 threadObj, thread_klass,
842 vmSymbols::dispatchUncaughtException_name(),
843 vmSymbols::throwable_void_signature(),
844 uncaught_exception,
845 THREAD);
846 if (HAS_PENDING_EXCEPTION) {
847 ResourceMark rm(this);
848 jio_fprintf(defaultStream::error_stream(),
849 "\nException: %s thrown from the UncaughtExceptionHandler"
850 " in thread \"%s\"\n",
851 pending_exception()->klass()->external_name(),
852 name());
853 CLEAR_PENDING_EXCEPTION;
854 }
855 }
856
857 if (!is_Compiler_thread()) {
858 // We have finished executing user-defined Java code and now have to do the
859 // implementation specific clean-up by calling Thread.exit(). We prevent any
860 // asynchronous exceptions from being delivered while in Thread.exit()
861 // to ensure the clean-up is not corrupted.
862 NoAsyncExceptionDeliveryMark _no_async(this);
863
864 EXCEPTION_MARK;
865 JavaValue result(T_VOID);
866 Klass* thread_klass = vmClasses::Thread_klass();
867 JavaCalls::call_virtual(&result,
868 threadObj, thread_klass,
869 vmSymbols::exit_method_name(),
870 vmSymbols::void_method_signature(),
871 THREAD);
872 CLEAR_PENDING_EXCEPTION;
873 }
874
875 // notify JVMTI
876 if (JvmtiExport::should_post_thread_life()) {
877 JvmtiExport::post_thread_end(this);
878 }
879 } else {
880 // before_exit() has already posted JVMTI THREAD_END events
881 }
882
883 // Cleanup any pending async exception now since we cannot access oops after
884 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
885 if (has_async_exception_condition()) {
886 handshake_state()->clean_async_exception_operation();
887 }
888
889 // The careful dance between thread suspension and exit is handled here.
890 // Since we are in thread_in_vm state and suspension is done with handshakes,
891 // we can just put in the exiting state and it will be correctly handled.
892 // Also, no more async exceptions will be added to the queue after this point.
893 set_terminated(_thread_exiting);
894 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
895
896 if (log_is_enabled(Debug, os, thread, timer)) {
897 _timer_exit_phase1.stop();
898 _timer_exit_phase2.start();
899 }
900
901 // Capture daemon status before the thread is marked as terminated.
902 bool daemon = is_daemon(threadObj());
903
904 // Notify waiters on thread object. This has to be done after exit() is called
905 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
906 // group should have the destroyed bit set before waiters are notified).
907 ensure_join(this);
908 assert(!this->has_pending_exception(), "ensure_join should have cleared");
909
910 if (log_is_enabled(Debug, os, thread, timer)) {
911 _timer_exit_phase2.stop();
912 _timer_exit_phase3.start();
913 }
914 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
915 // held by this thread must be released. The spec does not distinguish
916 // between JNI-acquired and regular Java monitors. We can only see
917 // regular Java monitors here if monitor enter-exit matching is broken.
918 //
919 // ensure_join() ignores IllegalThreadStateExceptions, and so does
920 // ObjectSynchronizer::release_monitors_owned_by_thread().
921 if (exit_type == jni_detach) {
922 // Sanity check even though JNI DetachCurrentThread() would have
923 // returned JNI_ERR if there was a Java frame. JavaThread exit
924 // should be done executing Java code by the time we get here.
925 assert(!this->has_last_Java_frame(),
926 "should not have a Java frame when detaching or exiting");
927 ObjectSynchronizer::release_monitors_owned_by_thread(this);
928 assert(!this->has_pending_exception(), "release_monitors should have cleared");
929 // Check for monitor counts being out of sync.
930 assert(held_monitor_count() == jni_monitor_count(),
931 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
932 held_monitor_count(), jni_monitor_count());
933 // All in-use monitors, including JNI-locked ones, should have been released above.
934 assert(held_monitor_count() == 0, "Failed to unlock " INTX_FORMAT " object monitors",
935 held_monitor_count());
936 } else {
937 // Check for monitor counts being out of sync.
938 assert(held_monitor_count() == jni_monitor_count(),
939 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
940 held_monitor_count(), jni_monitor_count());
941 // It is possible that a terminating thread failed to unlock monitors it locked
942 // via JNI so we don't assert the count is zero.
943 }
944
945 if (CheckJNICalls && jni_monitor_count() > 0) {
946 // We would like a fatal here, but due to we never checked this before there
947 // is a lot of tests which breaks, even with an error log.
948 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
949 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
950 }
951
952 // These things needs to be done while we are still a Java Thread. Make sure that thread
953 // is in a consistent state, in case GC happens
954 JFR_ONLY(Jfr::on_thread_exit(this);)
955
956 if (active_handles() != nullptr) {
957 JNIHandleBlock* block = active_handles();
958 set_active_handles(nullptr);
959 JNIHandleBlock::release_block(block);
960 }
961
962 if (free_handle_block() != nullptr) {
963 JNIHandleBlock* block = free_handle_block();
964 set_free_handle_block(nullptr);
965 JNIHandleBlock::release_block(block);
966 }
967
968 // These have to be removed while this is still a valid thread.
969 _stack_overflow_state.remove_stack_guard_pages();
970
971 if (UseTLAB) {
972 tlab().retire();
973 }
974
975 if (JvmtiEnv::environments_might_exist()) {
976 JvmtiExport::cleanup_thread(this);
977 }
978
979 // We need to cache the thread name for logging purposes below as once
980 // we have called on_thread_detach this thread must not access any oops.
981 char* thread_name = nullptr;
982 if (log_is_enabled(Debug, os, thread, timer)) {
983 ResourceMark rm(this);
984 thread_name = os::strdup(name());
985 }
986
987 if (log_is_enabled(Info, os, thread)) {
988 ResourceMark rm(this);
989 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: " UINTX_FORMAT ").",
990 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
991 name(), os::current_thread_id());
992 }
993
994 if (log_is_enabled(Debug, os, thread, timer)) {
995 _timer_exit_phase3.stop();
996 _timer_exit_phase4.start();
997 }
998
999 #if INCLUDE_JVMCI
1000 if (JVMCICounterSize > 0) {
1001 if (jvmci_counters_include(this)) {
1002 for (int i = 0; i < JVMCICounterSize; i++) {
1003 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
1004 }
1005 }
1006 }
1007 #endif // INCLUDE_JVMCI
1008
1009 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1010 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1011 Threads::remove(this, daemon);
1012
1013 if (log_is_enabled(Debug, os, thread, timer)) {
1014 _timer_exit_phase4.stop();
1015 log_debug(os, thread, timer)("name='%s'"
1016 ", exit-phase1=" JLONG_FORMAT
1017 ", exit-phase2=" JLONG_FORMAT
1018 ", exit-phase3=" JLONG_FORMAT
1019 ", exit-phase4=" JLONG_FORMAT,
1020 thread_name,
1021 _timer_exit_phase1.milliseconds(),
1022 _timer_exit_phase2.milliseconds(),
1023 _timer_exit_phase3.milliseconds(),
1024 _timer_exit_phase4.milliseconds());
1025 os::free(thread_name);
1026 }
1027 }
1028
1029 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1030 if (active_handles() != nullptr) {
1031 JNIHandleBlock* block = active_handles();
1032 set_active_handles(nullptr);
1033 JNIHandleBlock::release_block(block);
1034 }
1035
1036 if (free_handle_block() != nullptr) {
1037 JNIHandleBlock* block = free_handle_block();
1038 set_free_handle_block(nullptr);
1039 JNIHandleBlock::release_block(block);
1040 }
1041
1042 // These have to be removed while this is still a valid thread.
1043 _stack_overflow_state.remove_stack_guard_pages();
1044
1045 if (UseTLAB) {
1046 tlab().retire();
1047 }
1048
1049 Threads::remove(this, is_daemon);
1050 this->smr_delete();
1051 }
1052
1053 JavaThread* JavaThread::active() {
1054 Thread* thread = Thread::current();
1055 if (thread->is_Java_thread()) {
1056 return JavaThread::cast(thread);
1057 } else {
1058 assert(thread->is_VM_thread(), "this must be a vm thread");
1059 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1060 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1061 return ret;
1062 }
1063 }
1064
1065 bool JavaThread::is_lock_owned(address adr) const {
1066 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1067 return is_in_full_stack(adr);
1068 }
1069
1070 oop JavaThread::exception_oop() const {
1071 return Atomic::load(&_exception_oop);
1072 }
1073
1074 void JavaThread::set_exception_oop(oop o) {
1075 Atomic::store(&_exception_oop, o);
1076 }
1077
1078 void JavaThread::handle_special_runtime_exit_condition() {
1079 if (is_obj_deopt_suspend()) {
1080 frame_anchor()->make_walkable();
1081 wait_for_object_deoptimization();
1082 }
1083 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1084 }
1085
1086
1087 // Asynchronous exceptions support
1088 //
1089 void JavaThread::handle_async_exception(oop java_throwable) {
1090 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1091 assert(!is_at_poll_safepoint(), "should have never called this method");
1092
1093 if (has_last_Java_frame()) {
1094 frame f = last_frame();
1095 if (f.is_runtime_frame()) {
1096 // If the topmost frame is a runtime stub, then we are calling into
1097 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1098 // must deoptimize the caller before continuing, as the compiled exception
1099 // handler table may not be valid.
1100 RegisterMap reg_map(this,
1101 RegisterMap::UpdateMap::skip,
1102 RegisterMap::ProcessFrames::include,
1103 RegisterMap::WalkContinuation::skip);
1104 frame compiled_frame = f.sender(®_map);
1105 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1106 Deoptimization::deoptimize(this, compiled_frame);
1107 }
1108 }
1109 }
1110
1111 // We cannot call Exceptions::_throw(...) here because we cannot block
1112 set_pending_exception(java_throwable, __FILE__, __LINE__);
1113
1114 clear_scopedValueBindings();
1115
1116 LogTarget(Info, exceptions) lt;
1117 if (lt.is_enabled()) {
1118 ResourceMark rm;
1119 LogStream ls(lt);
1120 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1121 if (has_last_Java_frame()) {
1122 frame f = last_frame();
1123 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1124 }
1125 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1126 }
1127 }
1128
1129 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1130 // Do not throw asynchronous exceptions against the compiler thread
1131 // or if the thread is already exiting.
1132 if (!can_call_java() || is_exiting()) {
1133 delete aeh;
1134 return;
1135 }
1136
1137 oop exception = aeh->exception();
1138 Handshake::execute(aeh, this); // Install asynchronous handshake
1139
1140 ResourceMark rm;
1141 if (log_is_enabled(Info, exceptions)) {
1142 log_info(exceptions)("Pending Async. exception installed of type: %s",
1143 InstanceKlass::cast(exception->klass())->external_name());
1144 }
1145 // for AbortVMOnException flag
1146 Exceptions::debug_check_abort(exception->klass()->external_name());
1147
1148 oop vt_oop = vthread();
1149 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1150 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1151 java_lang_Thread::set_interrupted(threadObj(), true);
1152 this->interrupt();
1153 }
1154 }
1155
1156 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1157 AsyncExceptionHandshake* _aeh;
1158 public:
1159 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1160 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1161 ~InstallAsyncExceptionHandshake() {
1162 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1163 delete _aeh;
1164 }
1165 void do_thread(Thread* thr) {
1166 JavaThread* target = JavaThread::cast(thr);
1167 target->install_async_exception(_aeh);
1168 _aeh = nullptr;
1169 }
1170 };
1171
1172 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1173 OopHandle e(Universe::vm_global(), java_throwable);
1174 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1175 Handshake::execute(&iaeh, target);
1176 }
1177
1178 #if INCLUDE_JVMTI
1179 void JavaThread::set_is_in_VTMS_transition(bool val) {
1180 assert(is_in_VTMS_transition() != val, "already %s transition", val ? "inside" : "outside");
1181 _is_in_VTMS_transition = val;
1182 }
1183
1184 #ifdef ASSERT
1185 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1186 _is_VTMS_transition_disabler = val;
1187 }
1188 #endif
1189 #endif
1190
1191 // External suspension mechanism.
1192 //
1193 // Guarantees on return (for a valid target thread):
1194 // - Target thread will not execute any new bytecode.
1195 // - Target thread will not enter any new monitors.
1196 //
1197 bool JavaThread::java_suspend() {
1198 #if INCLUDE_JVMTI
1199 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1200 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1201 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1202 #endif
1203
1204 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1205 "target JavaThread is not protected in calling context.");
1206 return this->handshake_state()->suspend();
1207 }
1208
1209 bool JavaThread::java_resume() {
1210 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1211 "missing ThreadsListHandle in calling context.");
1212 return this->handshake_state()->resume();
1213 }
1214
1215 // Wait for another thread to perform object reallocation and relocking on behalf of
1216 // this thread. The current thread is required to change to _thread_blocked in order
1217 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1218 // handshake safe, the other thread can complete the handshake used to synchronize
1219 // with this thread and then perform the reallocation and relocking.
1220 // See EscapeBarrier::sync_and_suspend_*()
1221
1222 void JavaThread::wait_for_object_deoptimization() {
1223 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1224 assert(this == Thread::current(), "invariant");
1225
1226 bool spin_wait = os::is_MP();
1227 do {
1228 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1229 // Wait for object deoptimization if requested.
1230 if (spin_wait) {
1231 // A single deoptimization is typically very short. Microbenchmarks
1232 // showed 5% better performance when spinning.
1233 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1234 SpinYield spin(spin_limit);
1235 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1236 spin.wait();
1237 }
1238 // Spin just once
1239 spin_wait = false;
1240 } else {
1241 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1242 if (is_obj_deopt_suspend()) {
1243 ml.wait();
1244 }
1245 }
1246 // A handshake for obj. deoptimization suspend could have been processed so
1247 // we must check after processing.
1248 } while (is_obj_deopt_suspend());
1249 }
1250
1251 #ifdef ASSERT
1252 // Verify the JavaThread has not yet been published in the Threads::list, and
1253 // hence doesn't need protection from concurrent access at this stage.
1254 void JavaThread::verify_not_published() {
1255 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1256 // since an unpublished JavaThread doesn't participate in the
1257 // Thread-SMR protocol for keeping a ThreadsList alive.
1258 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1259 }
1260 #endif
1261
1262 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1263 // pending, when _suspend_flags is non-zero or when we need to process a stack
1264 // watermark. Also check for pending async exceptions (except unsafe access error).
1265 // Note only the native==>Java barriers can call this function when thread state
1266 // is _thread_in_native_trans.
1267 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1268 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1269 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1270
1271 thread->set_thread_state(_thread_in_vm);
1272
1273 // Enable WXWrite: called directly from interpreter native wrapper.
1274 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1275
1276 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1277
1278 // After returning from native, it could be that the stack frames are not
1279 // yet safe to use. We catch such situations in the subsequent stack watermark
1280 // barrier, which will trap unsafe stack frames.
1281 StackWatermarkSet::before_unwind(thread);
1282 }
1283
1284 #ifndef PRODUCT
1285 // Deoptimization
1286 // Function for testing deoptimization
1287 void JavaThread::deoptimize() {
1288 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1289 bool deopt = false; // Dump stack only if a deopt actually happens.
1290 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1291 // Iterate over all frames in the thread and deoptimize
1292 for (; !fst.is_done(); fst.next()) {
1293 if (fst.current()->can_be_deoptimized()) {
1294
1295 if (only_at) {
1296 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1297 // consists of comma or carriage return separated numbers so
1298 // search for the current bci in that string.
1299 address pc = fst.current()->pc();
1300 nmethod* nm = fst.current()->cb()->as_nmethod();
1301 ScopeDesc* sd = nm->scope_desc_at(pc);
1302 char buffer[8];
1303 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1304 size_t len = strlen(buffer);
1305 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1306 while (found != nullptr) {
1307 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1308 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1309 // Check that the bci found is bracketed by terminators.
1310 break;
1311 }
1312 found = strstr(found + 1, buffer);
1313 }
1314 if (!found) {
1315 continue;
1316 }
1317 }
1318
1319 if (DebugDeoptimization && !deopt) {
1320 deopt = true; // One-time only print before deopt
1321 tty->print_cr("[BEFORE Deoptimization]");
1322 trace_frames();
1323 trace_stack();
1324 }
1325 Deoptimization::deoptimize(this, *fst.current());
1326 }
1327 }
1328
1329 if (DebugDeoptimization && deopt) {
1330 tty->print_cr("[AFTER Deoptimization]");
1331 trace_frames();
1332 }
1333 }
1334
1335
1336 // Make zombies
1337 void JavaThread::make_zombies() {
1338 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1339 if (fst.current()->can_be_deoptimized()) {
1340 // it is a Java nmethod
1341 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1342 assert(nm != nullptr, "did not find nmethod");
1343 nm->make_not_entrant();
1344 }
1345 }
1346 }
1347 #endif // PRODUCT
1348
1349
1350 void JavaThread::deoptimize_marked_methods() {
1351 if (!has_last_Java_frame()) return;
1352 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1353 for (; !fst.is_done(); fst.next()) {
1354 if (fst.current()->should_be_deoptimized()) {
1355 Deoptimization::deoptimize(this, *fst.current());
1356 }
1357 }
1358 }
1359
1360 #ifdef ASSERT
1361 void JavaThread::verify_frame_info() {
1362 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1363 (has_last_Java_frame() && java_call_counter() > 0),
1364 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1365 has_last_Java_frame() ? "true" : "false", java_call_counter());
1366 }
1367 #endif
1368
1369 // Push on a new block of JNI handles.
1370 void JavaThread::push_jni_handle_block() {
1371 // Allocate a new block for JNI handles.
1372 // Inlined code from jni_PushLocalFrame()
1373 JNIHandleBlock* old_handles = active_handles();
1374 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1375 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1376 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1377 set_active_handles(new_handles);
1378 }
1379
1380 // Pop off the current block of JNI handles.
1381 void JavaThread::pop_jni_handle_block() {
1382 // Release our JNI handle block
1383 JNIHandleBlock* old_handles = active_handles();
1384 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1385 assert(new_handles != nullptr, "should never set active handles to null");
1386 set_active_handles(new_handles);
1387 old_handles->set_pop_frame_link(nullptr);
1388 JNIHandleBlock::release_block(old_handles, this);
1389 }
1390
1391 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1392 // Verify that the deferred card marks have been flushed.
1393 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1394
1395 // Traverse the GCHandles
1396 Thread::oops_do_no_frames(f, cf);
1397
1398 if (active_handles() != nullptr) {
1399 active_handles()->oops_do(f);
1400 }
1401
1402 DEBUG_ONLY(verify_frame_info();)
1403
1404 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1405 // If we have deferred set_locals there might be oops waiting to be
1406 // written
1407 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1408 if (list != nullptr) {
1409 for (int i = 0; i < list->length(); i++) {
1410 list->at(i)->oops_do(f);
1411 }
1412 }
1413
1414 // Traverse instance variables at the end since the GC may be moving things
1415 // around using this function
1416 f->do_oop((oop*) &_vm_result);
1417 f->do_oop((oop*) &_exception_oop);
1418 #if INCLUDE_JVMCI
1419 f->do_oop((oop*) &_jvmci_reserved_oop0);
1420
1421 if (_live_nmethod != nullptr && cf != nullptr) {
1422 cf->do_nmethod(_live_nmethod);
1423 }
1424 #endif
1425
1426 if (jvmti_thread_state() != nullptr) {
1427 jvmti_thread_state()->oops_do(f, cf);
1428 }
1429
1430 // The continuation oops are really on the stack. But there is typically at most
1431 // one of those per thread, so we handle them here in the oops_do_no_frames part
1432 // so that we don't have to sprinkle as many stack watermark checks where these
1433 // oops are used. We just need to make sure the thread has started processing.
1434 ContinuationEntry* entry = _cont_entry;
1435 while (entry != nullptr) {
1436 f->do_oop((oop*)entry->cont_addr());
1437 f->do_oop((oop*)entry->chunk_addr());
1438 entry = entry->parent();
1439 }
1440
1441 if (LockingMode == LM_LIGHTWEIGHT) {
1442 lock_stack().oops_do(f);
1443 }
1444 }
1445
1446 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1447 if (!has_last_Java_frame()) {
1448 return;
1449 }
1450 // Finish any pending lazy GC activity for the frames
1451 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1452 // Traverse the execution stack
1453 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1454 fst.current()->oops_do(f, cf, fst.register_map());
1455 }
1456 }
1457
1458 #ifdef ASSERT
1459 void JavaThread::verify_states_for_handshake() {
1460 // This checks that the thread has a correct frame state during a handshake.
1461 verify_frame_info();
1462 }
1463 #endif
1464
1465 void JavaThread::nmethods_do(NMethodClosure* cf) {
1466 DEBUG_ONLY(verify_frame_info();)
1467 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1468
1469 if (has_last_Java_frame()) {
1470 // Traverse the execution stack
1471 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1472 fst.current()->nmethod_do(cf);
1473 }
1474 }
1475
1476 if (jvmti_thread_state() != nullptr) {
1477 jvmti_thread_state()->nmethods_do(cf);
1478 }
1479
1480 #if INCLUDE_JVMCI
1481 if (_live_nmethod != nullptr) {
1482 cf->do_nmethod(_live_nmethod);
1483 }
1484 #endif
1485 }
1486
1487 void JavaThread::metadata_do(MetadataClosure* f) {
1488 if (has_last_Java_frame()) {
1489 // Traverse the execution stack to call f() on the methods in the stack
1490 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1491 fst.current()->metadata_do(f);
1492 }
1493 } else if (is_Compiler_thread()) {
1494 // need to walk ciMetadata in current compile tasks to keep alive.
1495 CompilerThread* ct = (CompilerThread*)this;
1496 if (ct->env() != nullptr) {
1497 ct->env()->metadata_do(f);
1498 }
1499 CompileTask* task = ct->task();
1500 if (task != nullptr) {
1501 task->metadata_do(f);
1502 }
1503 }
1504 }
1505
1506 // Printing
1507 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1508 switch (_thread_state) {
1509 case _thread_uninitialized: return "_thread_uninitialized";
1510 case _thread_new: return "_thread_new";
1511 case _thread_new_trans: return "_thread_new_trans";
1512 case _thread_in_native: return "_thread_in_native";
1513 case _thread_in_native_trans: return "_thread_in_native_trans";
1514 case _thread_in_vm: return "_thread_in_vm";
1515 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1516 case _thread_in_Java: return "_thread_in_Java";
1517 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1518 case _thread_blocked: return "_thread_blocked";
1519 case _thread_blocked_trans: return "_thread_blocked_trans";
1520 default: return "unknown thread state";
1521 }
1522 }
1523
1524 void JavaThread::print_thread_state_on(outputStream *st) const {
1525 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1526 }
1527
1528 // Called by Threads::print() for VM_PrintThreads operation
1529 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1530 st->print_raw("\"");
1531 st->print_raw(name());
1532 st->print_raw("\" ");
1533 oop thread_oop = threadObj();
1534 if (thread_oop != nullptr) {
1535 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1536 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1537 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1538 }
1539 Thread::print_on(st, print_extended_info);
1540 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1541 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1542 if (thread_oop != nullptr) {
1543 if (is_vthread_mounted()) {
1544 st->print(" Carrying virtual thread #");
1545 // _lock_id is the thread ID of the mounted virtual thread. If it equals
1546 // the tid of the carrier we caught thread at the start of a temporary
1547 // transition in VirtualThread.switchToCarrierThread. Ignore that case.
1548 if (lock_id() != java_lang_Thread::thread_id(thread_oop)) {
1549 st->print_cr(INT64_FORMAT, lock_id());
1550 } else {
1551 st->print_cr("%s", "(Unavailable)");
1552 }
1553 } else {
1554 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1555 }
1556 }
1557 #ifndef PRODUCT
1558 _safepoint_state->print_on(st);
1559 #endif // PRODUCT
1560 if (is_Compiler_thread()) {
1561 CompileTask *task = ((CompilerThread*)this)->task();
1562 if (task != nullptr) {
1563 st->print(" Compiling: ");
1564 task->print(st, nullptr, true, false);
1565 } else {
1566 st->print(" No compile task");
1567 }
1568 st->cr();
1569 }
1570 }
1571
1572 void JavaThread::print() const { print_on(tty); }
1573
1574 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1575 st->print("%s", get_thread_name_string(buf, buflen));
1576 }
1577
1578 // Called by fatal error handler. The difference between this and
1579 // JavaThread::print() is that we can't grab lock or allocate memory.
1580 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1581 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1582 Thread* current = Thread::current_or_null_safe();
1583 assert(current != nullptr, "cannot be called by a detached thread");
1584 st->fill_to(60);
1585 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1586 // Only access threadObj() if current thread is not a JavaThread
1587 // or if it is a JavaThread that can safely access oops.
1588 oop thread_obj = threadObj();
1589 if (thread_obj != nullptr) {
1590 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1591 }
1592 }
1593 st->print(" [");
1594 st->print("%s", _get_thread_state_name(_thread_state));
1595 if (osthread()) {
1596 st->print(", id=%d", osthread()->thread_id());
1597 }
1598 // Use raw field members for stack base/size as this could be
1599 // called before a thread has run enough to initialize them.
1600 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1601 p2i(_stack_base - _stack_size), p2i(_stack_base),
1602 PROPERFMTARGS(_stack_size));
1603 st->print("]");
1604
1605 ThreadsSMRSupport::print_info_on(this, st);
1606 return;
1607 }
1608
1609
1610 // Verification
1611
1612 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1613 // ignore if there is no stack
1614 if (!has_last_Java_frame()) return;
1615 // traverse the stack frames. Starts from top frame.
1616 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1617 frame* fr = fst.current();
1618 f(fr, fst.register_map());
1619 }
1620 }
1621
1622 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1623
1624 void JavaThread::verify() {
1625 // Verify oops in the thread.
1626 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1627
1628 // Verify the stack frames.
1629 frames_do(frame_verify);
1630 }
1631
1632 // CR 6300358 (sub-CR 2137150)
1633 // Most callers of this method assume that it can't return null but a
1634 // thread may not have a name whilst it is in the process of attaching to
1635 // the VM - see CR 6412693, and there are places where a JavaThread can be
1636 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1637 // if vm exit occurs during initialization). These cases can all be accounted
1638 // for such that this method never returns null.
1639 const char* JavaThread::name() const {
1640 if (Thread::is_JavaThread_protected(/* target */ this)) {
1641 // The target JavaThread is protected so get_thread_name_string() is safe:
1642 return get_thread_name_string();
1643 }
1644
1645 // The target JavaThread is not protected so we return the default:
1646 return Thread::name();
1647 }
1648
1649 // Like name() but doesn't include the protection check. This must only be
1650 // called when it is known to be safe, even though the protection check can't tell
1651 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1652 const char* JavaThread::name_raw() const {
1653 return get_thread_name_string();
1654 }
1655
1656 // Returns a non-null representation of this thread's name, or a suitable
1657 // descriptive string if there is no set name.
1658 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1659 const char* name_str;
1660 #ifdef ASSERT
1661 Thread* current = Thread::current_or_null_safe();
1662 assert(current != nullptr, "cannot be called by a detached thread");
1663 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1664 // Only access threadObj() if current thread is not a JavaThread
1665 // or if it is a JavaThread that can safely access oops.
1666 #endif
1667 oop thread_obj = threadObj();
1668 if (thread_obj != nullptr) {
1669 oop name = java_lang_Thread::name(thread_obj);
1670 if (name != nullptr) {
1671 if (buf == nullptr) {
1672 name_str = java_lang_String::as_utf8_string(name);
1673 } else {
1674 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1675 }
1676 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1677 name_str = "<no-name - thread is attaching>";
1678 } else {
1679 name_str = "<un-named>";
1680 }
1681 } else {
1682 name_str = Thread::name();
1683 }
1684 #ifdef ASSERT
1685 } else {
1686 // Current JavaThread has exited...
1687 if (current == this) {
1688 // ... and is asking about itself:
1689 name_str = "<no-name - current JavaThread has exited>";
1690 } else {
1691 // ... and it can't safely determine this JavaThread's name so
1692 // use the default thread name.
1693 name_str = Thread::name();
1694 }
1695 }
1696 #endif
1697 assert(name_str != nullptr, "unexpected null thread name");
1698 return name_str;
1699 }
1700
1701 // Helper to extract the name from the thread oop for logging.
1702 const char* JavaThread::name_for(oop thread_obj) {
1703 assert(thread_obj != nullptr, "precondition");
1704 oop name = java_lang_Thread::name(thread_obj);
1705 const char* name_str;
1706 if (name != nullptr) {
1707 name_str = java_lang_String::as_utf8_string(name);
1708 } else {
1709 name_str = "<un-named>";
1710 }
1711 return name_str;
1712 }
1713
1714 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1715
1716 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1717 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1718 // Link Java Thread object <-> C++ Thread
1719
1720 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1721 // and put it into a new Handle. The Handle "thread_oop" can then
1722 // be used to pass the C++ thread object to other methods.
1723
1724 // Set the Java level thread object (jthread) field of the
1725 // new thread (a JavaThread *) to C++ thread object using the
1726 // "thread_oop" handle.
1727
1728 // Set the thread field (a JavaThread *) of the
1729 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1730
1731 Handle thread_oop(Thread::current(),
1732 JNIHandles::resolve_non_null(jni_thread));
1733 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1734 "must be initialized");
1735 set_threadOopHandles(thread_oop());
1736 set_lock_id(java_lang_Thread::thread_id(thread_oop()));
1737
1738 if (prio == NoPriority) {
1739 prio = java_lang_Thread::priority(thread_oop());
1740 assert(prio != NoPriority, "A valid priority should be present");
1741 }
1742
1743 // Push the Java priority down to the native thread; needs Threads_lock
1744 Thread::set_priority(this, prio);
1745
1746 // Add the new thread to the Threads list and set it in motion.
1747 // We must have threads lock in order to call Threads::add.
1748 // It is crucial that we do not block before the thread is
1749 // added to the Threads list for if a GC happens, then the java_thread oop
1750 // will not be visited by GC.
1751 Threads::add(this);
1752 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1753 // on a ThreadsList. We don't want to wait for the release when the
1754 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1755 // is already visible to JVM/TI via the ThreadsList.
1756 java_lang_Thread::release_set_thread(thread_oop(), this);
1757 }
1758
1759 oop JavaThread::current_park_blocker() {
1760 // Support for JSR-166 locks
1761 oop thread_oop = threadObj();
1762 if (thread_oop != nullptr) {
1763 return java_lang_Thread::park_blocker(thread_oop);
1764 }
1765 return nullptr;
1766 }
1767
1768 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1769 // This is the external format, selecting the platform or vthread
1770 // as applicable, and allowing for a native-only stack.
1771 void JavaThread::print_jni_stack() {
1772 assert(this == JavaThread::current(), "Can't print stack of other threads");
1773 if (!has_last_Java_frame()) {
1774 ResourceMark rm(this);
1775 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1776 if (buf == nullptr) {
1777 tty->print_cr("Unable to print native stack - out of memory");
1778 return;
1779 }
1780 address lastpc = nullptr;
1781 if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) {
1782 // We have printed the native stack in platform-specific code,
1783 // so nothing else to do in this case.
1784 } else {
1785 frame f = os::current_frame();
1786 VMError::print_native_stack(tty, f, this, true /*print_source_info */,
1787 -1 /* max stack */, buf, O_BUFLEN);
1788 }
1789 } else {
1790 print_active_stack_on(tty);
1791 }
1792 }
1793
1794 void JavaThread::print_stack_on(outputStream* st) {
1795 if (!has_last_Java_frame()) return;
1796
1797 Thread* current_thread = Thread::current();
1798 ResourceMark rm(current_thread);
1799 HandleMark hm(current_thread);
1800
1801 RegisterMap reg_map(this,
1802 RegisterMap::UpdateMap::include,
1803 RegisterMap::ProcessFrames::include,
1804 RegisterMap::WalkContinuation::skip);
1805 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1806 int count = 0;
1807 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1808 if (f->is_java_frame()) {
1809 javaVFrame* jvf = javaVFrame::cast(f);
1810 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1811
1812 // Print out lock information
1813 if (JavaMonitorsInStackTrace) {
1814 jvf->print_lock_info_on(st, count);
1815 }
1816 } else {
1817 // Ignore non-Java frames
1818 }
1819
1820 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1821 count++;
1822 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1823 }
1824 }
1825
1826 void JavaThread::print_vthread_stack_on(outputStream* st) {
1827 assert(is_vthread_mounted(), "Caller should have checked this");
1828 assert(has_last_Java_frame(), "must be");
1829
1830 Thread* current_thread = Thread::current();
1831 ResourceMark rm(current_thread);
1832 HandleMark hm(current_thread);
1833
1834 RegisterMap reg_map(this,
1835 RegisterMap::UpdateMap::include,
1836 RegisterMap::ProcessFrames::include,
1837 RegisterMap::WalkContinuation::include);
1838 ContinuationEntry* cont_entry = last_continuation();
1839 vframe* start_vf = last_java_vframe(®_map);
1840 int count = 0;
1841 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1842 // Watch for end of vthread stack
1843 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1844 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1845 if (cont_entry->is_virtual_thread()) {
1846 break;
1847 }
1848 cont_entry = cont_entry->parent();
1849 }
1850 if (f->is_java_frame()) {
1851 javaVFrame* jvf = javaVFrame::cast(f);
1852 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1853
1854 // Print out lock information
1855 if (JavaMonitorsInStackTrace) {
1856 jvf->print_lock_info_on(st, count);
1857 }
1858 } else {
1859 // Ignore non-Java frames
1860 }
1861
1862 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1863 count++;
1864 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1865 }
1866 }
1867
1868 void JavaThread::print_active_stack_on(outputStream* st) {
1869 if (is_vthread_mounted()) {
1870 print_vthread_stack_on(st);
1871 } else {
1872 print_stack_on(st);
1873 }
1874 }
1875
1876 #if INCLUDE_JVMTI
1877 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1878 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1879 set_jvmti_vthread(thread_oop);
1880
1881 // unbind current JvmtiThreadState from JavaThread
1882 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1883
1884 // bind new JvmtiThreadState to JavaThread
1885 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1886
1887 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1888 JvmtiThreadState::process_pending_interp_only(this);
1889
1890 return jvmti_thread_state();
1891 }
1892 #endif
1893
1894 // JVMTI PopFrame support
1895 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1896 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1897 if (in_bytes(size_in_bytes) != 0) {
1898 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1899 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1900 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1901 }
1902 }
1903
1904 void* JavaThread::popframe_preserved_args() {
1905 return _popframe_preserved_args;
1906 }
1907
1908 ByteSize JavaThread::popframe_preserved_args_size() {
1909 return in_ByteSize(_popframe_preserved_args_size);
1910 }
1911
1912 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1913 int sz = in_bytes(popframe_preserved_args_size());
1914 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1915 return in_WordSize(sz / wordSize);
1916 }
1917
1918 void JavaThread::popframe_free_preserved_args() {
1919 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1920 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1921 _popframe_preserved_args = nullptr;
1922 _popframe_preserved_args_size = 0;
1923 }
1924
1925 #ifndef PRODUCT
1926
1927 void JavaThread::trace_frames() {
1928 tty->print_cr("[Describe stack]");
1929 int frame_no = 1;
1930 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1931 tty->print(" %d. ", frame_no++);
1932 fst.current()->print_value_on(tty);
1933 tty->cr();
1934 }
1935 }
1936
1937 class PrintAndVerifyOopClosure: public OopClosure {
1938 protected:
1939 template <class T> inline void do_oop_work(T* p) {
1940 oop obj = RawAccess<>::oop_load(p);
1941 if (obj == nullptr) return;
1942 tty->print(INTPTR_FORMAT ": ", p2i(p));
1943 if (oopDesc::is_oop_or_null(obj)) {
1944 if (obj->is_objArray()) {
1945 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1946 } else {
1947 obj->print();
1948 }
1949 } else {
1950 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1951 }
1952 tty->cr();
1953 }
1954 public:
1955 virtual void do_oop(oop* p) { do_oop_work(p); }
1956 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1957 };
1958
1959 #ifdef ASSERT
1960 // Print or validate the layout of stack frames
1961 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1962 ResourceMark rm;
1963 PreserveExceptionMark pm(this);
1964 FrameValues values;
1965 int frame_no = 0;
1966 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1967 fst.current()->describe(values, ++frame_no, fst.register_map());
1968 if (depth == frame_no) break;
1969 }
1970 Continuation::describe(values);
1971 if (validate_only) {
1972 values.validate();
1973 } else {
1974 tty->print_cr("[Describe stack layout]");
1975 values.print(this);
1976 }
1977 }
1978 #endif
1979
1980 void JavaThread::trace_stack_from(vframe* start_vf) {
1981 ResourceMark rm;
1982 int vframe_no = 1;
1983 for (vframe* f = start_vf; f; f = f->sender()) {
1984 if (f->is_java_frame()) {
1985 javaVFrame::cast(f)->print_activation(vframe_no++);
1986 } else {
1987 f->print();
1988 }
1989 if (vframe_no > StackPrintLimit) {
1990 tty->print_cr("...<more frames>...");
1991 return;
1992 }
1993 }
1994 }
1995
1996
1997 void JavaThread::trace_stack() {
1998 if (!has_last_Java_frame()) return;
1999 Thread* current_thread = Thread::current();
2000 ResourceMark rm(current_thread);
2001 HandleMark hm(current_thread);
2002 RegisterMap reg_map(this,
2003 RegisterMap::UpdateMap::include,
2004 RegisterMap::ProcessFrames::include,
2005 RegisterMap::WalkContinuation::skip);
2006 trace_stack_from(last_java_vframe(®_map));
2007 }
2008
2009
2010 #endif // PRODUCT
2011
2012 // Slow-path increment of the held monitor counts. JNI locking is always
2013 // this slow-path.
2014 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2015 #ifdef SUPPORT_MONITOR_COUNT
2016
2017 if (LockingMode != LM_LEGACY) {
2018 // Nothing to do. Just do some sanity check.
2019 assert(_held_monitor_count == 0, "counter should not be used");
2020 assert(_jni_monitor_count == 0, "counter should not be used");
2021 return;
2022 }
2023
2024 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
2025 _held_monitor_count += i;
2026 if (jni) {
2027 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
2028 _jni_monitor_count += i;
2029 }
2030 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2031 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2032 #endif // SUPPORT_MONITOR_COUNT
2033 }
2034
2035 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2036 // this slow-path.
2037 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2038 #ifdef SUPPORT_MONITOR_COUNT
2039
2040 if (LockingMode != LM_LEGACY) {
2041 // Nothing to do. Just do some sanity check.
2042 assert(_held_monitor_count == 0, "counter should not be used");
2043 assert(_jni_monitor_count == 0, "counter should not be used");
2044 return;
2045 }
2046
2047 _held_monitor_count -= i;
2048 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
2049 if (jni) {
2050 _jni_monitor_count -= i;
2051 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
2052 }
2053 // When a thread is detaching with still owned JNI monitors, the logic that releases
2054 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2055 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2056 // JNI count is directly set to zero.
2057 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2058 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2059 #endif // SUPPORT_MONITOR_COUNT
2060 }
2061
2062 frame JavaThread::vthread_last_frame() {
2063 assert (is_vthread_mounted(), "Virtual thread not mounted");
2064 return last_frame();
2065 }
2066
2067 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2068 const ContinuationEntry* entry = vthread_continuation();
2069 guarantee (entry != nullptr, "Not a carrier thread");
2070 frame f = entry->to_frame();
2071 if (reg_map->process_frames()) {
2072 entry->flush_stack_processing(this);
2073 }
2074 entry->update_register_map(reg_map);
2075 return f.sender(reg_map);
2076 }
2077
2078 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2079 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2080 }
2081
2082 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2083 assert(reg_map != nullptr, "a map must be given");
2084 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2085 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2086 }
2087 return nullptr;
2088 }
2089
2090 Klass* JavaThread::security_get_caller_class(int depth) {
2091 ResetNoHandleMark rnhm;
2092 HandleMark hm(Thread::current());
2093
2094 vframeStream vfst(this);
2095 vfst.security_get_caller_frame(depth);
2096 if (!vfst.at_end()) {
2097 return vfst.method()->method_holder();
2098 }
2099 return nullptr;
2100 }
2101
2102 // Internal convenience function for millisecond resolution sleeps.
2103 bool JavaThread::sleep(jlong millis) {
2104 jlong nanos;
2105 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2106 // Conversion to nanos would overflow, saturate at max
2107 nanos = max_jlong;
2108 } else {
2109 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2110 }
2111 return sleep_nanos(nanos);
2112 }
2113
2114 // java.lang.Thread.sleep support
2115 // Returns true if sleep time elapsed as expected, and false
2116 // if the thread was interrupted.
2117 bool JavaThread::sleep_nanos(jlong nanos) {
2118 assert(this == Thread::current(), "thread consistency check");
2119 assert(nanos >= 0, "nanos are in range");
2120
2121 ParkEvent * const slp = this->_SleepEvent;
2122 // Because there can be races with thread interruption sending an unpark()
2123 // to the event, we explicitly reset it here to avoid an immediate return.
2124 // The actual interrupt state will be checked before we park().
2125 slp->reset();
2126 // Thread interruption establishes a happens-before ordering in the
2127 // Java Memory Model, so we need to ensure we synchronize with the
2128 // interrupt state.
2129 OrderAccess::fence();
2130
2131 jlong prevtime = os::javaTimeNanos();
2132
2133 jlong nanos_remaining = nanos;
2134
2135 for (;;) {
2136 // interruption has precedence over timing out
2137 if (this->is_interrupted(true)) {
2138 return false;
2139 }
2140
2141 if (nanos_remaining <= 0) {
2142 return true;
2143 }
2144
2145 {
2146 ThreadBlockInVM tbivm(this);
2147 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2148 slp->park_nanos(nanos_remaining);
2149 }
2150
2151 // Update elapsed time tracking
2152 jlong newtime = os::javaTimeNanos();
2153 if (newtime - prevtime < 0) {
2154 // time moving backwards, should only happen if no monotonic clock
2155 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2156 assert(false,
2157 "unexpected time moving backwards detected in JavaThread::sleep()");
2158 } else {
2159 nanos_remaining -= (newtime - prevtime);
2160 }
2161 prevtime = newtime;
2162 }
2163 }
2164
2165 // Last thread running calls java.lang.Shutdown.shutdown()
2166 void JavaThread::invoke_shutdown_hooks() {
2167 HandleMark hm(this);
2168
2169 // We could get here with a pending exception, if so clear it now.
2170 if (this->has_pending_exception()) {
2171 this->clear_pending_exception();
2172 }
2173
2174 EXCEPTION_MARK;
2175 Klass* shutdown_klass =
2176 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2177 THREAD);
2178 if (shutdown_klass != nullptr) {
2179 // SystemDictionary::resolve_or_null will return null if there was
2180 // an exception. If we cannot load the Shutdown class, just don't
2181 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2182 // won't be run. Note that if a shutdown hook was registered,
2183 // the Shutdown class would have already been loaded
2184 // (Runtime.addShutdownHook will load it).
2185 JavaValue result(T_VOID);
2186 JavaCalls::call_static(&result,
2187 shutdown_klass,
2188 vmSymbols::shutdown_name(),
2189 vmSymbols::void_method_signature(),
2190 THREAD);
2191 }
2192 CLEAR_PENDING_EXCEPTION;
2193 }
2194
2195 #ifndef PRODUCT
2196 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2197 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2198 }
2199 #endif
2200
2201 // Helper function to create the java.lang.Thread object for a
2202 // VM-internal thread. The thread will have the given name, and be
2203 // a member of the "system" ThreadGroup.
2204 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2205 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2206
2207 // Initialize thread_oop to put it into the system threadGroup.
2208 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2209 Handle thread_group(THREAD, Universe::system_thread_group());
2210 Handle thread_oop =
2211 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2212 vmSymbols::threadgroup_string_void_signature(),
2213 thread_group,
2214 string,
2215 CHECK_NH);
2216
2217 return thread_oop;
2218 }
2219
2220 // Starts the target JavaThread as a daemon of the given priority, and
2221 // bound to the given java.lang.Thread instance.
2222 // The Threads_lock is held for the duration.
2223 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2224 Handle thread_oop, ThreadPriority prio) {
2225
2226 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2227
2228 MutexLocker mu(current, Threads_lock);
2229
2230 // Initialize the fields of the thread_oop first.
2231 if (prio != NoPriority) {
2232 java_lang_Thread::set_priority(thread_oop(), prio);
2233 // Note: we don't call os::set_priority here. Possibly we should,
2234 // else all threads should call it themselves when they first run.
2235 }
2236
2237 java_lang_Thread::set_daemon(thread_oop());
2238
2239 // Now bind the thread_oop to the target JavaThread.
2240 target->set_threadOopHandles(thread_oop());
2241 target->set_lock_id(java_lang_Thread::thread_id(thread_oop()));
2242
2243 Threads::add(target); // target is now visible for safepoint/handshake
2244 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2245 // on a ThreadsList. We don't want to wait for the release when the
2246 // Theads_lock is dropped when the 'mu' destructor is run since the
2247 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2248
2249 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2250 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2251 Thread::start(target);
2252 }
2253
2254 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2255 // At this point it may be possible that no osthread was created for the
2256 // JavaThread due to lack of resources. However, since this must work
2257 // for critical system threads just check and abort if this fails.
2258 if (thread->osthread() == nullptr) {
2259 // This isn't really an OOM condition, but historically this is what
2260 // we report.
2261 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2262 os::native_thread_creation_failed_msg());
2263 }
2264 }
2265
2266 void JavaThread::pretouch_stack() {
2267 // Given an established java thread stack with usable area followed by
2268 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2269 // from the current frame down to the start of the shadow zone.
2270 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2271 if (is_in_full_stack(end)) {
2272 char* p1 = (char*) alloca(1);
2273 address here = (address) &p1;
2274 if (is_in_full_stack(here) && here > end) {
2275 size_t to_alloc = here - end;
2276 char* p2 = (char*) alloca(to_alloc);
2277 log_trace(os, thread)("Pretouching thread stack for " UINTX_FORMAT ": " RANGEFMT ".",
2278 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2279 os::pretouch_memory(p2, p2 + to_alloc,
2280 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2281 }
2282 }
2283 }
2284
2285 // Deferred OopHandle release support.
2286
2287 class OopHandleList : public CHeapObj<mtInternal> {
2288 static const int _count = 4;
2289 OopHandle _handles[_count];
2290 OopHandleList* _next;
2291 int _index;
2292 public:
2293 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2294 void add(OopHandle h) {
2295 assert(_index < _count, "too many additions");
2296 _handles[_index++] = h;
2297 }
2298 ~OopHandleList() {
2299 assert(_index == _count, "usage error");
2300 for (int i = 0; i < _index; i++) {
2301 _handles[i].release(JavaThread::thread_oop_storage());
2302 }
2303 }
2304 OopHandleList* next() const { return _next; }
2305 };
2306
2307 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2308
2309 // Called by the ServiceThread to do the work of releasing
2310 // the OopHandles.
2311 void JavaThread::release_oop_handles() {
2312 OopHandleList* list;
2313 {
2314 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2315 list = _oop_handle_list;
2316 _oop_handle_list = nullptr;
2317 }
2318 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2319
2320 while (list != nullptr) {
2321 OopHandleList* l = list;
2322 list = l->next();
2323 delete l;
2324 }
2325 }
2326
2327 // Add our OopHandles for later release.
2328 void JavaThread::add_oop_handles_for_release() {
2329 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2330 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2331 new_head->add(_threadObj);
2332 new_head->add(_vthread);
2333 new_head->add(_jvmti_vthread);
2334 new_head->add(_scopedValueCache);
2335 _oop_handle_list = new_head;
2336 Service_lock->notify_all();
2337 }