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/inlineKlass.hpp"
52 #include "oops/instanceKlass.hpp"
53 #include "oops/klass.inline.hpp"
54 #include "oops/oop.inline.hpp"
55 #include "oops/oopHandle.inline.hpp"
56 #include "oops/verifyOopClosure.hpp"
57 #include "prims/jvm_misc.hpp"
58 #include "prims/jvmtiDeferredUpdates.hpp"
59 #include "prims/jvmtiExport.hpp"
60 #include "prims/jvmtiThreadState.inline.hpp"
61 #include "runtime/atomic.hpp"
62 #include "runtime/continuation.hpp"
63 #include "runtime/continuationEntry.inline.hpp"
64 #include "runtime/continuationHelper.inline.hpp"
65 #include "runtime/deoptimization.hpp"
66 #include "runtime/frame.inline.hpp"
67 #include "runtime/handles.inline.hpp"
68 #include "runtime/handshake.hpp"
69 #include "runtime/interfaceSupport.inline.hpp"
70 #include "runtime/java.hpp"
71 #include "runtime/javaCalls.hpp"
72 #include "runtime/javaThread.inline.hpp"
73 #include "runtime/jniHandles.inline.hpp"
74 #include "runtime/lockStack.inline.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.hpp"
77 #include "runtime/os.inline.hpp"
78 #include "runtime/osThread.hpp"
79 #include "runtime/safepoint.hpp"
80 #include "runtime/safepointMechanism.inline.hpp"
81 #include "runtime/safepointVerifiers.hpp"
82 #include "runtime/serviceThread.hpp"
83 #include "runtime/stackFrameStream.inline.hpp"
84 #include "runtime/stackWatermarkSet.hpp"
85 #include "runtime/synchronizer.hpp"
86 #include "runtime/threadCritical.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
240 JavaValue result(T_VOID);
241 if (thread_name != nullptr) {
242 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
243 // Thread gets assigned specified name and null target
244 JavaCalls::call_special(&result,
245 thread_oop,
246 ik,
247 vmSymbols::object_initializer_name(),
248 vmSymbols::threadgroup_string_void_signature(),
249 thread_group,
250 name,
251 CHECK);
252 } else {
253 // Thread gets assigned name "Thread-nnn" and null target
254 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
255 JavaCalls::call_special(&result,
256 thread_oop,
257 ik,
258 vmSymbols::object_initializer_name(),
259 vmSymbols::threadgroup_runnable_void_signature(),
260 thread_group,
261 Handle(),
262 CHECK);
263 }
264 os::set_priority(this, NormPriority);
265
266 if (daemon) {
267 java_lang_Thread::set_daemon(thread_oop());
268 }
269 }
270
271 // ======= JavaThread ========
272
273 #if INCLUDE_JVMCI
274
275 jlong* JavaThread::_jvmci_old_thread_counters;
276
277 static bool jvmci_counters_include(JavaThread* thread) {
278 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
279 }
280
281 void JavaThread::collect_counters(jlong* array, int length) {
282 assert(length == JVMCICounterSize, "wrong value");
283 for (int i = 0; i < length; i++) {
284 array[i] = _jvmci_old_thread_counters[i];
285 }
286 for (JavaThread* tp : ThreadsListHandle()) {
287 if (jvmci_counters_include(tp)) {
288 for (int i = 0; i < length; i++) {
289 array[i] += tp->_jvmci_counters[i];
290 }
291 }
292 }
293 }
294
295 // Attempt to enlarge the array for per thread counters.
296 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
297 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
298 if (new_counters == nullptr) {
299 return nullptr;
300 }
301 if (old_counters == nullptr) {
302 old_counters = new_counters;
303 memset(old_counters, 0, sizeof(jlong) * new_size);
304 } else {
305 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
306 new_counters[i] = old_counters[i];
307 }
308 if (new_size > current_size) {
309 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
310 }
311 FREE_C_HEAP_ARRAY(jlong, old_counters);
312 }
313 return new_counters;
314 }
315
316 // Attempt to enlarge the array for per thread counters.
317 bool JavaThread::resize_counters(int current_size, int new_size) {
318 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
319 if (new_counters == nullptr) {
320 return false;
321 } else {
322 _jvmci_counters = new_counters;
323 return true;
324 }
325 }
326
327 class VM_JVMCIResizeCounters : public VM_Operation {
328 private:
329 int _new_size;
330 bool _failed;
331
332 public:
333 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
334 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
335 bool allow_nested_vm_operations() const { return true; }
336 void doit() {
337 // Resize the old thread counters array
338 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
339 if (new_counters == nullptr) {
340 _failed = true;
341 return;
342 } else {
343 JavaThread::_jvmci_old_thread_counters = new_counters;
344 }
345
346 // Now resize each threads array
347 for (JavaThread* tp : ThreadsListHandle()) {
348 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
349 _failed = true;
350 break;
351 }
352 }
353 if (!_failed) {
354 JVMCICounterSize = _new_size;
355 }
356 }
357
358 bool failed() { return _failed; }
359 };
360
361 bool JavaThread::resize_all_jvmci_counters(int new_size) {
362 VM_JVMCIResizeCounters op(new_size);
363 VMThread::execute(&op);
364 return !op.failed();
365 }
366
367 #endif // INCLUDE_JVMCI
368
369 #ifdef ASSERT
370 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
371 void JavaThread::check_possible_safepoint() {
372 if (_no_safepoint_count > 0) {
373 print_owned_locks();
374 assert(false, "Possible safepoint reached by thread that does not allow it");
375 }
376 #ifdef CHECK_UNHANDLED_OOPS
377 // Clear unhandled oops in JavaThreads so we get a crash right away.
378 clear_unhandled_oops();
379 #endif // CHECK_UNHANDLED_OOPS
380
381 // Macos/aarch64 should be in the right state for safepoint (e.g.
382 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
383 // happens in practice, making such issues hard to find and reproduce.
384 #if defined(__APPLE__) && defined(AARCH64)
385 if (AssertWXAtThreadSync) {
386 assert_wx_state(WXWrite);
387 }
388 #endif
389 }
390
391 void JavaThread::check_for_valid_safepoint_state() {
392 // Don't complain if running a debugging command.
393 if (DebuggingContext::is_enabled()) return;
394
395 // Check NoSafepointVerifier, which is implied by locks taken that can be
396 // shared with the VM thread. This makes sure that no locks with allow_vm_block
397 // are held.
398 check_possible_safepoint();
399
400 if (thread_state() != _thread_in_vm) {
401 fatal("LEAF method calling lock?");
402 }
403
404 if (GCALotAtAllSafepoints) {
405 // We could enter a safepoint here and thus have a gc
406 InterfaceSupport::check_gc_alot();
407 }
408 }
409 #endif // ASSERT
410
411 // A JavaThread is a normal Java thread
412
413 JavaThread::JavaThread(MemTag mem_tag) :
414 Thread(mem_tag),
415 // Initialize fields
416 _on_thread_list(false),
417 DEBUG_ONLY(_java_call_counter(0) COMMA)
418 _entry_point(nullptr),
419 _deopt_mark(nullptr),
420 _deopt_nmethod(nullptr),
421 _vframe_array_head(nullptr),
422 _vframe_array_last(nullptr),
423 _jvmti_deferred_updates(nullptr),
424 _callee_target(nullptr),
425 _vm_result(nullptr),
426 _vm_result_2(nullptr),
427
428 _current_pending_monitor(nullptr),
429 _current_pending_monitor_is_from_java(true),
430 _current_waiting_monitor(nullptr),
431 _active_handles(nullptr),
432 _free_handle_block(nullptr),
433
434 _suspend_flags(0),
435
436 _thread_state(_thread_new),
437 _saved_exception_pc(nullptr),
438 #ifdef ASSERT
439 _no_safepoint_count(0),
440 _visited_for_critical_count(false),
441 #endif
442
443 _terminated(_not_terminated),
444 _in_deopt_handler(0),
445 _doing_unsafe_access(false),
446 _do_not_unlock_if_synchronized(false),
447 #if INCLUDE_JVMTI
448 _carrier_thread_suspended(false),
449 _is_in_VTMS_transition(false),
450 _is_in_tmp_VTMS_transition(false),
451 _is_disable_suspend(false),
452 _VTMS_transition_mark(false),
453 #ifdef ASSERT
454 _is_VTMS_transition_disabler(false),
455 #endif
456 #endif
457 _jni_attach_state(_not_attaching_via_jni),
458 _is_in_internal_oome_mark(false),
459 #if INCLUDE_JVMCI
460 _pending_deoptimization(-1),
461 _pending_monitorenter(false),
462 _pending_transfer_to_interpreter(false),
463 _pending_failed_speculation(0),
464 _jvmci{nullptr},
465 _libjvmci_runtime(nullptr),
466 _jvmci_counters(nullptr),
467 _jvmci_reserved0(0),
468 _jvmci_reserved1(0),
469 _jvmci_reserved_oop0(nullptr),
470 _live_nmethod(nullptr),
471 #endif // INCLUDE_JVMCI
472
473 _exception_oop(oop()),
474 _exception_pc(nullptr),
475 _exception_handler_pc(nullptr),
476 _is_method_handle_return(0),
477
478 _jni_active_critical(0),
479 _pending_jni_exception_check_fn(nullptr),
480 _depth_first_number(0),
481
482 // JVMTI PopFrame support
483 _popframe_condition(popframe_inactive),
484 _frames_to_pop_failed_realloc(0),
485
486 _cont_entry(nullptr),
487 _cont_fastpath(nullptr),
488 _cont_fastpath_thread_state(1),
489 _held_monitor_count(0),
490 _jni_monitor_count(0),
491 _unlocked_inflated_monitor(nullptr),
492
493 _handshake(this),
494
495 _popframe_preserved_args(nullptr),
496 _popframe_preserved_args_size(0),
497
498 _jvmti_thread_state(nullptr),
499 _interp_only_mode(0),
500 _should_post_on_exceptions_flag(JNI_FALSE),
501 _thread_stat(new ThreadStatistics()),
502
503 _parker(),
504
505 _class_to_be_initialized(nullptr),
506
507 _SleepEvent(ParkEvent::Allocate(this)),
508
509 _lock_stack(this),
510 _om_cache(this) {
511 set_jni_functions(jni_functions());
512
513 #if INCLUDE_JVMCI
514 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
515 if (JVMCICounterSize > 0) {
516 resize_counters(0, (int) JVMCICounterSize);
517 }
518 #endif // INCLUDE_JVMCI
519
520 // Setup safepoint state info for this thread
521 ThreadSafepointState::create(this);
522
523 SafepointMechanism::initialize_header(this);
524
525 set_requires_cross_modify_fence(false);
526
527 pd_initialize();
528 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
529 }
530
531 JavaThread* JavaThread::create_attaching_thread() {
532 JavaThread* jt = new JavaThread();
533 jt->_jni_attach_state = _attaching_via_jni;
534 return jt;
535 }
536
537 // interrupt support
538
539 void JavaThread::interrupt() {
540 // All callers should have 'this' thread protected by a
541 // ThreadsListHandle so that it cannot terminate and deallocate
542 // itself.
543 debug_only(check_for_dangling_thread_pointer(this);)
544
545 // For Windows _interrupt_event
546 WINDOWS_ONLY(osthread()->set_interrupted(true);)
547
548 // For Thread.sleep
549 _SleepEvent->unpark();
550
551 // For JSR166 LockSupport.park
552 parker()->unpark();
553
554 // For ObjectMonitor and JvmtiRawMonitor
555 _ParkEvent->unpark();
556 }
557
558 bool JavaThread::is_interrupted(bool clear_interrupted) {
559 debug_only(check_for_dangling_thread_pointer(this);)
560
561 if (_threadObj.peek() == nullptr) {
562 // If there is no j.l.Thread then it is impossible to have
563 // been interrupted. We can find null during VM initialization
564 // or when a JNI thread is still in the process of attaching.
565 // In such cases this must be the current thread.
566 assert(this == Thread::current(), "invariant");
567 return false;
568 }
569
570 bool interrupted = java_lang_Thread::interrupted(threadObj());
571
572 // NOTE that since there is no "lock" around the interrupt and
573 // is_interrupted operations, there is the possibility that the
574 // interrupted flag will be "false" but that the
575 // low-level events will be in the signaled state. This is
576 // intentional. The effect of this is that Object.wait() and
577 // LockSupport.park() will appear to have a spurious wakeup, which
578 // is allowed and not harmful, and the possibility is so rare that
579 // it is not worth the added complexity to add yet another lock.
580 // For the sleep event an explicit reset is performed on entry
581 // to JavaThread::sleep, so there is no early return. It has also been
582 // recommended not to put the interrupted flag into the "event"
583 // structure because it hides the issue.
584 // Also, because there is no lock, we must only clear the interrupt
585 // state if we are going to report that we were interrupted; otherwise
586 // an interrupt that happens just after we read the field would be lost.
587 if (interrupted && clear_interrupted) {
588 assert(this == Thread::current(), "only the current thread can clear");
589 java_lang_Thread::set_interrupted(threadObj(), false);
590 WINDOWS_ONLY(osthread()->set_interrupted(false);)
591 }
592 return interrupted;
593 }
594
595 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
596 // the Java code in Object::wait which are not present in RawMonitorWait.
597 bool JavaThread::get_and_clear_interrupted() {
598 if (!is_interrupted(false)) {
599 return false;
600 }
601 oop thread_oop = vthread_or_thread();
602 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
603
604 if (!is_virtual) {
605 return is_interrupted(true);
606 }
607 // Virtual thread: clear interrupt status for both virtual and
608 // carrier threads under the interruptLock protection.
609 JavaThread* current = JavaThread::current();
610 HandleMark hm(current);
611 Handle thread_h(current, thread_oop);
612 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
613
614 // re-check the interrupt status under the interruptLock protection
615 bool interrupted = java_lang_Thread::interrupted(thread_h());
616
617 if (interrupted) {
618 assert(this == Thread::current(), "only the current thread can clear");
619 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
620 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
621 WINDOWS_ONLY(osthread()->set_interrupted(false);)
622 }
623 return interrupted;
624 }
625
626 void JavaThread::block_if_vm_exited() {
627 if (_terminated == _vm_exited) {
628 // _vm_exited is set at safepoint, and Threads_lock is never released
629 // so we will block here forever.
630 // Here we can be doing a jump from a safe state to an unsafe state without
631 // proper transition, but it happens after the final safepoint has begun so
632 // this jump won't cause any safepoint problems.
633 set_thread_state(_thread_in_vm);
634 Threads_lock->lock();
635 ShouldNotReachHere();
636 }
637 }
638
639 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
640 set_entry_point(entry_point);
641 // Create the native thread itself.
642 // %note runtime_23
643 os::ThreadType thr_type = os::java_thread;
644 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
645 os::java_thread;
646 os::create_thread(this, thr_type, stack_sz);
647 // The _osthread may be null here because we ran out of memory (too many threads active).
648 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
649 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
650 // the exception consists of creating the exception object & initializing it, initialization
651 // will leave the VM via a JavaCall and then all locks must be unlocked).
652 //
653 // The thread is still suspended when we reach here. Thread must be explicit started
654 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
655 // by calling Threads:add. The reason why this is not done here, is because the thread
656 // object must be fully initialized (take a look at JVM_Start)
657 }
658
659 JavaThread::~JavaThread() {
660
661 // Enqueue OopHandles for release by the service thread.
662 add_oop_handles_for_release();
663
664 // Return the sleep event to the free list
665 ParkEvent::Release(_SleepEvent);
666 _SleepEvent = nullptr;
667
668 // Free any remaining previous UnrollBlock
669 vframeArray* old_array = vframe_array_last();
670
671 if (old_array != nullptr) {
672 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
673 old_array->set_unroll_block(nullptr);
674 delete old_info;
675 delete old_array;
676 }
677
678 JvmtiDeferredUpdates* updates = deferred_updates();
679 if (updates != nullptr) {
680 // This can only happen if thread is destroyed before deoptimization occurs.
681 assert(updates->count() > 0, "Updates holder not deleted");
682 // free deferred updates.
683 delete updates;
684 set_deferred_updates(nullptr);
685 }
686
687 // All Java related clean up happens in exit
688 ThreadSafepointState::destroy(this);
689 if (_thread_stat != nullptr) delete _thread_stat;
690
691 #if INCLUDE_JVMCI
692 if (JVMCICounterSize > 0) {
693 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
694 }
695 #endif // INCLUDE_JVMCI
696 }
697
698
699 // First JavaThread specific code executed by a new Java thread.
700 void JavaThread::pre_run() {
701 // empty - see comments in run()
702 }
703
704 // The main routine called by a new Java thread. This isn't overridden
705 // by subclasses, instead different subclasses define a different "entry_point"
706 // which defines the actual logic for that kind of thread.
707 void JavaThread::run() {
708 // initialize thread-local alloc buffer related fields
709 initialize_tlab();
710
711 _stack_overflow_state.create_stack_guard_pages();
712
713 cache_global_variables();
714
715 // Thread is now sufficiently initialized to be handled by the safepoint code as being
716 // in the VM. Change thread state from _thread_new to _thread_in_vm
717 assert(this->thread_state() == _thread_new, "wrong thread state");
718 set_thread_state(_thread_in_vm);
719
720 // Before a thread is on the threads list it is always safe, so after leaving the
721 // _thread_new we should emit a instruction barrier. The distance to modified code
722 // from here is probably far enough, but this is consistent and safe.
723 OrderAccess::cross_modify_fence();
724
725 assert(JavaThread::current() == this, "sanity check");
726 assert(!Thread::current()->owns_locks(), "sanity check");
727
728 DTRACE_THREAD_PROBE(start, this);
729
730 // This operation might block. We call that after all safepoint checks for a new thread has
731 // been completed.
732 set_active_handles(JNIHandleBlock::allocate_block());
733
734 if (JvmtiExport::should_post_thread_life()) {
735 JvmtiExport::post_thread_start(this);
736
737 }
738
739 if (AlwaysPreTouchStacks) {
740 pretouch_stack();
741 }
742
743 // We call another function to do the rest so we are sure that the stack addresses used
744 // from there will be lower than the stack base just computed.
745 thread_main_inner();
746 }
747
748 void JavaThread::thread_main_inner() {
749 assert(JavaThread::current() == this, "sanity check");
750 assert(_threadObj.peek() != nullptr, "just checking");
751
752 // Execute thread entry point unless this thread has a pending exception.
753 // Note: Due to JVMTI StopThread we can have pending exceptions already!
754 if (!this->has_pending_exception()) {
755 {
756 ResourceMark rm(this);
757 this->set_native_thread_name(this->name());
758 }
759 HandleMark hm(this);
760 this->entry_point()(this, this);
761 }
762
763 DTRACE_THREAD_PROBE(stop, this);
764
765 // Cleanup is handled in post_run()
766 }
767
768 // Shared teardown for all JavaThreads
769 void JavaThread::post_run() {
770 this->exit(false);
771 this->unregister_thread_stack_with_NMT();
772 // Defer deletion to here to ensure 'this' is still referenceable in call_run
773 // for any shared tear-down.
774 this->smr_delete();
775 }
776
777 static void ensure_join(JavaThread* thread) {
778 // We do not need to grab the Threads_lock, since we are operating on ourself.
779 Handle threadObj(thread, thread->threadObj());
780 assert(threadObj.not_null(), "java thread object must exist");
781 ObjectLocker lock(threadObj, thread);
782 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
783 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
784 // Clear the native thread instance - this makes isAlive return false and allows the join()
785 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
786 // requirements.
787 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
788 java_lang_Thread::release_set_thread(threadObj(), nullptr);
789 lock.notify_all(thread);
790 // Ignore pending exception, since we are exiting anyway
791 thread->clear_pending_exception();
792 }
793
794 static bool is_daemon(oop threadObj) {
795 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
796 }
797
798 // For any new cleanup additions, please check to see if they need to be applied to
799 // cleanup_failed_attach_current_thread as well.
800 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
801 assert(this == JavaThread::current(), "thread consistency check");
802 assert(!is_exiting(), "should not be exiting or terminated already");
803
804 elapsedTimer _timer_exit_phase1;
805 elapsedTimer _timer_exit_phase2;
806 elapsedTimer _timer_exit_phase3;
807 elapsedTimer _timer_exit_phase4;
808
809 om_clear_monitor_cache();
810
811 if (log_is_enabled(Debug, os, thread, timer)) {
812 _timer_exit_phase1.start();
813 }
814
815 HandleMark hm(this);
816 Handle uncaught_exception(this, this->pending_exception());
817 this->clear_pending_exception();
818 Handle threadObj(this, this->threadObj());
819 assert(threadObj.not_null(), "Java thread object should be created");
820
821 if (!destroy_vm) {
822 if (uncaught_exception.not_null()) {
823 EXCEPTION_MARK;
824 // Call method Thread.dispatchUncaughtException().
825 Klass* thread_klass = vmClasses::Thread_klass();
826 JavaValue result(T_VOID);
827 JavaCalls::call_virtual(&result,
828 threadObj, thread_klass,
829 vmSymbols::dispatchUncaughtException_name(),
830 vmSymbols::throwable_void_signature(),
831 uncaught_exception,
832 THREAD);
833 if (HAS_PENDING_EXCEPTION) {
834 ResourceMark rm(this);
835 jio_fprintf(defaultStream::error_stream(),
836 "\nException: %s thrown from the UncaughtExceptionHandler"
837 " in thread \"%s\"\n",
838 pending_exception()->klass()->external_name(),
839 name());
840 CLEAR_PENDING_EXCEPTION;
841 }
842 }
843
844 if (!is_Compiler_thread()) {
845 // We have finished executing user-defined Java code and now have to do the
846 // implementation specific clean-up by calling Thread.exit(). We prevent any
847 // asynchronous exceptions from being delivered while in Thread.exit()
848 // to ensure the clean-up is not corrupted.
849 NoAsyncExceptionDeliveryMark _no_async(this);
850
851 EXCEPTION_MARK;
852 JavaValue result(T_VOID);
853 Klass* thread_klass = vmClasses::Thread_klass();
854 JavaCalls::call_virtual(&result,
855 threadObj, thread_klass,
856 vmSymbols::exit_method_name(),
857 vmSymbols::void_method_signature(),
858 THREAD);
859 CLEAR_PENDING_EXCEPTION;
860 }
861
862 // notify JVMTI
863 if (JvmtiExport::should_post_thread_life()) {
864 JvmtiExport::post_thread_end(this);
865 }
866 } else {
867 // before_exit() has already posted JVMTI THREAD_END events
868 }
869
870 // Cleanup any pending async exception now since we cannot access oops after
871 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
872 if (has_async_exception_condition()) {
873 handshake_state()->clean_async_exception_operation();
874 }
875
876 // The careful dance between thread suspension and exit is handled here.
877 // Since we are in thread_in_vm state and suspension is done with handshakes,
878 // we can just put in the exiting state and it will be correctly handled.
879 // Also, no more async exceptions will be added to the queue after this point.
880 set_terminated(_thread_exiting);
881 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
882
883 if (log_is_enabled(Debug, os, thread, timer)) {
884 _timer_exit_phase1.stop();
885 _timer_exit_phase2.start();
886 }
887
888 // Capture daemon status before the thread is marked as terminated.
889 bool daemon = is_daemon(threadObj());
890
891 // Notify waiters on thread object. This has to be done after exit() is called
892 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
893 // group should have the destroyed bit set before waiters are notified).
894 ensure_join(this);
895 assert(!this->has_pending_exception(), "ensure_join should have cleared");
896
897 if (log_is_enabled(Debug, os, thread, timer)) {
898 _timer_exit_phase2.stop();
899 _timer_exit_phase3.start();
900 }
901 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
902 // held by this thread must be released. The spec does not distinguish
903 // between JNI-acquired and regular Java monitors. We can only see
904 // regular Java monitors here if monitor enter-exit matching is broken.
905 //
906 // ensure_join() ignores IllegalThreadStateExceptions, and so does
907 // ObjectSynchronizer::release_monitors_owned_by_thread().
908 if (exit_type == jni_detach) {
909 // Sanity check even though JNI DetachCurrentThread() would have
910 // returned JNI_ERR if there was a Java frame. JavaThread exit
911 // should be done executing Java code by the time we get here.
912 assert(!this->has_last_Java_frame(),
913 "should not have a Java frame when detaching or exiting");
914 ObjectSynchronizer::release_monitors_owned_by_thread(this);
915 assert(!this->has_pending_exception(), "release_monitors should have cleared");
916 // Check for monitor counts being out of sync.
917 assert(held_monitor_count() == jni_monitor_count(),
918 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
919 held_monitor_count(), jni_monitor_count());
920 // All in-use monitors, including JNI-locked ones, should have been released above.
921 assert(held_monitor_count() == 0, "Failed to unlock " INTX_FORMAT " object monitors",
922 held_monitor_count());
923 } else {
924 // Check for monitor counts being out of sync.
925 assert(held_monitor_count() == jni_monitor_count(),
926 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
927 held_monitor_count(), jni_monitor_count());
928 // It is possible that a terminating thread failed to unlock monitors it locked
929 // via JNI so we don't assert the count is zero.
930 }
931
932 if (CheckJNICalls && jni_monitor_count() > 0) {
933 // We would like a fatal here, but due to we never checked this before there
934 // is a lot of tests which breaks, even with an error log.
935 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
936 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
937 }
938
939 // These things needs to be done while we are still a Java Thread. Make sure that thread
940 // is in a consistent state, in case GC happens
941 JFR_ONLY(Jfr::on_thread_exit(this);)
942
943 if (active_handles() != nullptr) {
944 JNIHandleBlock* block = active_handles();
945 set_active_handles(nullptr);
946 JNIHandleBlock::release_block(block);
947 }
948
949 if (free_handle_block() != nullptr) {
950 JNIHandleBlock* block = free_handle_block();
951 set_free_handle_block(nullptr);
952 JNIHandleBlock::release_block(block);
953 }
954
955 // These have to be removed while this is still a valid thread.
956 _stack_overflow_state.remove_stack_guard_pages();
957
958 if (UseTLAB) {
959 tlab().retire();
960 }
961
962 if (JvmtiEnv::environments_might_exist()) {
963 JvmtiExport::cleanup_thread(this);
964 }
965
966 // We need to cache the thread name for logging purposes below as once
967 // we have called on_thread_detach this thread must not access any oops.
968 char* thread_name = nullptr;
969 if (log_is_enabled(Debug, os, thread, timer)) {
970 ResourceMark rm(this);
971 thread_name = os::strdup(name());
972 }
973
974 if (log_is_enabled(Info, os, thread)) {
975 ResourceMark rm(this);
976 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: " UINTX_FORMAT ").",
977 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
978 name(), os::current_thread_id());
979 }
980
981 if (log_is_enabled(Debug, os, thread, timer)) {
982 _timer_exit_phase3.stop();
983 _timer_exit_phase4.start();
984 }
985
986 #if INCLUDE_JVMCI
987 if (JVMCICounterSize > 0) {
988 if (jvmci_counters_include(this)) {
989 for (int i = 0; i < JVMCICounterSize; i++) {
990 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
991 }
992 }
993 }
994 #endif // INCLUDE_JVMCI
995
996 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
997 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
998 Threads::remove(this, daemon);
999
1000 if (log_is_enabled(Debug, os, thread, timer)) {
1001 _timer_exit_phase4.stop();
1002 log_debug(os, thread, timer)("name='%s'"
1003 ", exit-phase1=" JLONG_FORMAT
1004 ", exit-phase2=" JLONG_FORMAT
1005 ", exit-phase3=" JLONG_FORMAT
1006 ", exit-phase4=" JLONG_FORMAT,
1007 thread_name,
1008 _timer_exit_phase1.milliseconds(),
1009 _timer_exit_phase2.milliseconds(),
1010 _timer_exit_phase3.milliseconds(),
1011 _timer_exit_phase4.milliseconds());
1012 os::free(thread_name);
1013 }
1014 }
1015
1016 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1017 if (active_handles() != nullptr) {
1018 JNIHandleBlock* block = active_handles();
1019 set_active_handles(nullptr);
1020 JNIHandleBlock::release_block(block);
1021 }
1022
1023 if (free_handle_block() != nullptr) {
1024 JNIHandleBlock* block = free_handle_block();
1025 set_free_handle_block(nullptr);
1026 JNIHandleBlock::release_block(block);
1027 }
1028
1029 // These have to be removed while this is still a valid thread.
1030 _stack_overflow_state.remove_stack_guard_pages();
1031
1032 if (UseTLAB) {
1033 tlab().retire();
1034 }
1035
1036 Threads::remove(this, is_daemon);
1037 this->smr_delete();
1038 }
1039
1040 JavaThread* JavaThread::active() {
1041 Thread* thread = Thread::current();
1042 if (thread->is_Java_thread()) {
1043 return JavaThread::cast(thread);
1044 } else {
1045 assert(thread->is_VM_thread(), "this must be a vm thread");
1046 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1047 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1048 return ret;
1049 }
1050 }
1051
1052 bool JavaThread::is_lock_owned(address adr) const {
1053 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1054 return is_in_full_stack(adr);
1055 }
1056
1057 oop JavaThread::exception_oop() const {
1058 return Atomic::load(&_exception_oop);
1059 }
1060
1061 void JavaThread::set_exception_oop(oop o) {
1062 Atomic::store(&_exception_oop, o);
1063 }
1064
1065 void JavaThread::handle_special_runtime_exit_condition() {
1066 if (is_obj_deopt_suspend()) {
1067 frame_anchor()->make_walkable();
1068 wait_for_object_deoptimization();
1069 }
1070 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1071 }
1072
1073
1074 // Asynchronous exceptions support
1075 //
1076 void JavaThread::handle_async_exception(oop java_throwable) {
1077 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1078 assert(!is_at_poll_safepoint(), "should have never called this method");
1079
1080 if (has_last_Java_frame()) {
1081 frame f = last_frame();
1082 if (f.is_runtime_frame()) {
1083 // If the topmost frame is a runtime stub, then we are calling into
1084 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1085 // must deoptimize the caller before continuing, as the compiled exception
1086 // handler table may not be valid.
1087 RegisterMap reg_map(this,
1088 RegisterMap::UpdateMap::skip,
1089 RegisterMap::ProcessFrames::include,
1090 RegisterMap::WalkContinuation::skip);
1091 frame compiled_frame = f.sender(®_map);
1092 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1093 Deoptimization::deoptimize(this, compiled_frame);
1094 }
1095 }
1096 }
1097
1098 // We cannot call Exceptions::_throw(...) here because we cannot block
1099 set_pending_exception(java_throwable, __FILE__, __LINE__);
1100
1101 clear_scopedValueBindings();
1102
1103 LogTarget(Info, exceptions) lt;
1104 if (lt.is_enabled()) {
1105 ResourceMark rm;
1106 LogStream ls(lt);
1107 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1108 if (has_last_Java_frame()) {
1109 frame f = last_frame();
1110 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1111 }
1112 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1113 }
1114 }
1115
1116 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1117 // Do not throw asynchronous exceptions against the compiler thread
1118 // or if the thread is already exiting.
1119 if (!can_call_java() || is_exiting()) {
1120 delete aeh;
1121 return;
1122 }
1123
1124 oop exception = aeh->exception();
1125 Handshake::execute(aeh, this); // Install asynchronous handshake
1126
1127 ResourceMark rm;
1128 if (log_is_enabled(Info, exceptions)) {
1129 log_info(exceptions)("Pending Async. exception installed of type: %s",
1130 InstanceKlass::cast(exception->klass())->external_name());
1131 }
1132 // for AbortVMOnException flag
1133 Exceptions::debug_check_abort(exception->klass()->external_name());
1134
1135 oop vt_oop = vthread();
1136 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1137 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1138 java_lang_Thread::set_interrupted(threadObj(), true);
1139 this->interrupt();
1140 }
1141 }
1142
1143 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1144 AsyncExceptionHandshake* _aeh;
1145 public:
1146 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1147 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1148 ~InstallAsyncExceptionHandshake() {
1149 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1150 delete _aeh;
1151 }
1152 void do_thread(Thread* thr) {
1153 JavaThread* target = JavaThread::cast(thr);
1154 target->install_async_exception(_aeh);
1155 _aeh = nullptr;
1156 }
1157 };
1158
1159 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1160 OopHandle e(Universe::vm_global(), java_throwable);
1161 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1162 Handshake::execute(&iaeh, target);
1163 }
1164
1165 #if INCLUDE_JVMTI
1166 void JavaThread::set_is_in_VTMS_transition(bool val) {
1167 _is_in_VTMS_transition = val;
1168 }
1169
1170 #ifdef ASSERT
1171 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1172 _is_VTMS_transition_disabler = val;
1173 }
1174 #endif
1175 #endif
1176
1177 // External suspension mechanism.
1178 //
1179 // Guarantees on return (for a valid target thread):
1180 // - Target thread will not execute any new bytecode.
1181 // - Target thread will not enter any new monitors.
1182 //
1183 bool JavaThread::java_suspend() {
1184 #if INCLUDE_JVMTI
1185 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1186 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1187 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1188 #endif
1189
1190 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1191 "target JavaThread is not protected in calling context.");
1192 return this->handshake_state()->suspend();
1193 }
1194
1195 bool JavaThread::java_resume() {
1196 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1197 "missing ThreadsListHandle in calling context.");
1198 return this->handshake_state()->resume();
1199 }
1200
1201 // Wait for another thread to perform object reallocation and relocking on behalf of
1202 // this thread. The current thread is required to change to _thread_blocked in order
1203 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1204 // handshake safe, the other thread can complete the handshake used to synchronize
1205 // with this thread and then perform the reallocation and relocking.
1206 // See EscapeBarrier::sync_and_suspend_*()
1207
1208 void JavaThread::wait_for_object_deoptimization() {
1209 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1210 assert(this == Thread::current(), "invariant");
1211
1212 bool spin_wait = os::is_MP();
1213 do {
1214 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1215 // Wait for object deoptimization if requested.
1216 if (spin_wait) {
1217 // A single deoptimization is typically very short. Microbenchmarks
1218 // showed 5% better performance when spinning.
1219 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1220 SpinYield spin(spin_limit);
1221 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1222 spin.wait();
1223 }
1224 // Spin just once
1225 spin_wait = false;
1226 } else {
1227 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1228 if (is_obj_deopt_suspend()) {
1229 ml.wait();
1230 }
1231 }
1232 // A handshake for obj. deoptimization suspend could have been processed so
1233 // we must check after processing.
1234 } while (is_obj_deopt_suspend());
1235 }
1236
1237 #ifdef ASSERT
1238 // Verify the JavaThread has not yet been published in the Threads::list, and
1239 // hence doesn't need protection from concurrent access at this stage.
1240 void JavaThread::verify_not_published() {
1241 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1242 // since an unpublished JavaThread doesn't participate in the
1243 // Thread-SMR protocol for keeping a ThreadsList alive.
1244 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1245 }
1246 #endif
1247
1248 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1249 // pending, when _suspend_flags is non-zero or when we need to process a stack
1250 // watermark. Also check for pending async exceptions (except unsafe access error).
1251 // Note only the native==>Java barriers can call this function when thread state
1252 // is _thread_in_native_trans.
1253 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1254 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1255 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1256
1257 thread->set_thread_state(_thread_in_vm);
1258
1259 // Enable WXWrite: called directly from interpreter native wrapper.
1260 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1261
1262 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1263
1264 // After returning from native, it could be that the stack frames are not
1265 // yet safe to use. We catch such situations in the subsequent stack watermark
1266 // barrier, which will trap unsafe stack frames.
1267 StackWatermarkSet::before_unwind(thread);
1268 }
1269
1270 #ifndef PRODUCT
1271 // Deoptimization
1272 // Function for testing deoptimization
1273 void JavaThread::deoptimize() {
1274 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1275 bool deopt = false; // Dump stack only if a deopt actually happens.
1276 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1277 // Iterate over all frames in the thread and deoptimize
1278 for (; !fst.is_done(); fst.next()) {
1279 if (fst.current()->can_be_deoptimized()) {
1280
1281 if (only_at) {
1282 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1283 // consists of comma or carriage return separated numbers so
1284 // search for the current bci in that string.
1285 address pc = fst.current()->pc();
1286 nmethod* nm = fst.current()->cb()->as_nmethod();
1287 ScopeDesc* sd = nm->scope_desc_at(pc);
1288 char buffer[8];
1289 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1290 size_t len = strlen(buffer);
1291 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1292 while (found != nullptr) {
1293 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1294 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1295 // Check that the bci found is bracketed by terminators.
1296 break;
1297 }
1298 found = strstr(found + 1, buffer);
1299 }
1300 if (!found) {
1301 continue;
1302 }
1303 }
1304
1305 if (DebugDeoptimization && !deopt) {
1306 deopt = true; // One-time only print before deopt
1307 tty->print_cr("[BEFORE Deoptimization]");
1308 trace_frames();
1309 trace_stack();
1310 }
1311 Deoptimization::deoptimize(this, *fst.current());
1312 }
1313 }
1314
1315 if (DebugDeoptimization && deopt) {
1316 tty->print_cr("[AFTER Deoptimization]");
1317 trace_frames();
1318 }
1319 }
1320
1321
1322 // Make zombies
1323 void JavaThread::make_zombies() {
1324 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1325 if (fst.current()->can_be_deoptimized()) {
1326 // it is a Java nmethod
1327 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1328 assert(nm != nullptr, "did not find nmethod");
1329 nm->make_not_entrant();
1330 }
1331 }
1332 }
1333 #endif // PRODUCT
1334
1335
1336 void JavaThread::deoptimize_marked_methods() {
1337 if (!has_last_Java_frame()) return;
1338 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1339 for (; !fst.is_done(); fst.next()) {
1340 if (fst.current()->should_be_deoptimized()) {
1341 Deoptimization::deoptimize(this, *fst.current());
1342 }
1343 }
1344 }
1345
1346 #ifdef ASSERT
1347 void JavaThread::verify_frame_info() {
1348 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1349 (has_last_Java_frame() && java_call_counter() > 0),
1350 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1351 has_last_Java_frame() ? "true" : "false", java_call_counter());
1352 }
1353 #endif
1354
1355 // Push on a new block of JNI handles.
1356 void JavaThread::push_jni_handle_block() {
1357 // Allocate a new block for JNI handles.
1358 // Inlined code from jni_PushLocalFrame()
1359 JNIHandleBlock* old_handles = active_handles();
1360 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1361 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1362 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1363 set_active_handles(new_handles);
1364 }
1365
1366 // Pop off the current block of JNI handles.
1367 void JavaThread::pop_jni_handle_block() {
1368 // Release our JNI handle block
1369 JNIHandleBlock* old_handles = active_handles();
1370 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1371 assert(new_handles != nullptr, "should never set active handles to null");
1372 set_active_handles(new_handles);
1373 old_handles->set_pop_frame_link(nullptr);
1374 JNIHandleBlock::release_block(old_handles, this);
1375 }
1376
1377 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1378 // Verify that the deferred card marks have been flushed.
1379 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1380
1381 // Traverse the GCHandles
1382 Thread::oops_do_no_frames(f, cf);
1383
1384 if (active_handles() != nullptr) {
1385 active_handles()->oops_do(f);
1386 }
1387
1388 DEBUG_ONLY(verify_frame_info();)
1389
1390 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1391 // If we have deferred set_locals there might be oops waiting to be
1392 // written
1393 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1394 if (list != nullptr) {
1395 for (int i = 0; i < list->length(); i++) {
1396 list->at(i)->oops_do(f);
1397 }
1398 }
1399
1400 // Traverse instance variables at the end since the GC may be moving things
1401 // around using this function
1402 f->do_oop((oop*) &_vm_result);
1403 f->do_oop((oop*) &_exception_oop);
1404 #if INCLUDE_JVMCI
1405 f->do_oop((oop*) &_jvmci_reserved_oop0);
1406
1407 if (_live_nmethod != nullptr && cf != nullptr) {
1408 cf->do_nmethod(_live_nmethod);
1409 }
1410 #endif
1411
1412 if (jvmti_thread_state() != nullptr) {
1413 jvmti_thread_state()->oops_do(f, cf);
1414 }
1415
1416 // The continuation oops are really on the stack. But there is typically at most
1417 // one of those per thread, so we handle them here in the oops_do_no_frames part
1418 // so that we don't have to sprinkle as many stack watermark checks where these
1419 // oops are used. We just need to make sure the thread has started processing.
1420 ContinuationEntry* entry = _cont_entry;
1421 while (entry != nullptr) {
1422 f->do_oop((oop*)entry->cont_addr());
1423 f->do_oop((oop*)entry->chunk_addr());
1424 entry = entry->parent();
1425 }
1426
1427 if (LockingMode == LM_LIGHTWEIGHT) {
1428 lock_stack().oops_do(f);
1429 }
1430 }
1431
1432 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1433 if (!has_last_Java_frame()) {
1434 return;
1435 }
1436 // Finish any pending lazy GC activity for the frames
1437 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1438 // Traverse the execution stack
1439 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1440 fst.current()->oops_do(f, cf, fst.register_map());
1441 }
1442 }
1443
1444 #ifdef ASSERT
1445 void JavaThread::verify_states_for_handshake() {
1446 // This checks that the thread has a correct frame state during a handshake.
1447 verify_frame_info();
1448 }
1449 #endif
1450
1451 void JavaThread::nmethods_do(NMethodClosure* cf) {
1452 DEBUG_ONLY(verify_frame_info();)
1453 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1454
1455 if (has_last_Java_frame()) {
1456 // Traverse the execution stack
1457 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1458 fst.current()->nmethod_do(cf);
1459 }
1460 }
1461
1462 if (jvmti_thread_state() != nullptr) {
1463 jvmti_thread_state()->nmethods_do(cf);
1464 }
1465
1466 #if INCLUDE_JVMCI
1467 if (_live_nmethod != nullptr) {
1468 cf->do_nmethod(_live_nmethod);
1469 }
1470 #endif
1471 }
1472
1473 void JavaThread::metadata_do(MetadataClosure* f) {
1474 if (has_last_Java_frame()) {
1475 // Traverse the execution stack to call f() on the methods in the stack
1476 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1477 fst.current()->metadata_do(f);
1478 }
1479 } else if (is_Compiler_thread()) {
1480 // need to walk ciMetadata in current compile tasks to keep alive.
1481 CompilerThread* ct = (CompilerThread*)this;
1482 if (ct->env() != nullptr) {
1483 ct->env()->metadata_do(f);
1484 }
1485 CompileTask* task = ct->task();
1486 if (task != nullptr) {
1487 task->metadata_do(f);
1488 }
1489 }
1490 }
1491
1492 // Printing
1493 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1494 switch (_thread_state) {
1495 case _thread_uninitialized: return "_thread_uninitialized";
1496 case _thread_new: return "_thread_new";
1497 case _thread_new_trans: return "_thread_new_trans";
1498 case _thread_in_native: return "_thread_in_native";
1499 case _thread_in_native_trans: return "_thread_in_native_trans";
1500 case _thread_in_vm: return "_thread_in_vm";
1501 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1502 case _thread_in_Java: return "_thread_in_Java";
1503 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1504 case _thread_blocked: return "_thread_blocked";
1505 case _thread_blocked_trans: return "_thread_blocked_trans";
1506 default: return "unknown thread state";
1507 }
1508 }
1509
1510 void JavaThread::print_thread_state_on(outputStream *st) const {
1511 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1512 }
1513
1514 // Called by Threads::print() for VM_PrintThreads operation
1515 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1516 st->print_raw("\"");
1517 st->print_raw(name());
1518 st->print_raw("\" ");
1519 oop thread_oop = threadObj();
1520 if (thread_oop != nullptr) {
1521 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1522 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1523 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1524 }
1525 Thread::print_on(st, print_extended_info);
1526 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1527 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1528 if (thread_oop != nullptr) {
1529 if (is_vthread_mounted()) {
1530 oop vt = vthread();
1531 assert(vt != nullptr, "");
1532 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1533 } else {
1534 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1535 }
1536 }
1537 #ifndef PRODUCT
1538 _safepoint_state->print_on(st);
1539 #endif // PRODUCT
1540 if (is_Compiler_thread()) {
1541 CompileTask *task = ((CompilerThread*)this)->task();
1542 if (task != nullptr) {
1543 st->print(" Compiling: ");
1544 task->print(st, nullptr, true, false);
1545 } else {
1546 st->print(" No compile task");
1547 }
1548 st->cr();
1549 }
1550 }
1551
1552 void JavaThread::print() const { print_on(tty); }
1553
1554 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1555 st->print("%s", get_thread_name_string(buf, buflen));
1556 }
1557
1558 // Called by fatal error handler. The difference between this and
1559 // JavaThread::print() is that we can't grab lock or allocate memory.
1560 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1561 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1562 Thread* current = Thread::current_or_null_safe();
1563 assert(current != nullptr, "cannot be called by a detached thread");
1564 st->fill_to(60);
1565 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1566 // Only access threadObj() if current thread is not a JavaThread
1567 // or if it is a JavaThread that can safely access oops.
1568 oop thread_obj = threadObj();
1569 if (thread_obj != nullptr) {
1570 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1571 }
1572 }
1573 st->print(" [");
1574 st->print("%s", _get_thread_state_name(_thread_state));
1575 if (osthread()) {
1576 st->print(", id=%d", osthread()->thread_id());
1577 }
1578 // Use raw field members for stack base/size as this could be
1579 // called before a thread has run enough to initialize them.
1580 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1581 p2i(_stack_base - _stack_size), p2i(_stack_base),
1582 PROPERFMTARGS(_stack_size));
1583 st->print("]");
1584
1585 ThreadsSMRSupport::print_info_on(this, st);
1586 return;
1587 }
1588
1589
1590 // Verification
1591
1592 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1593 // ignore if there is no stack
1594 if (!has_last_Java_frame()) return;
1595 // traverse the stack frames. Starts from top frame.
1596 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1597 frame* fr = fst.current();
1598 f(fr, fst.register_map());
1599 }
1600 }
1601
1602 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1603
1604 void JavaThread::verify() {
1605 // Verify oops in the thread.
1606 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1607
1608 // Verify the stack frames.
1609 frames_do(frame_verify);
1610 }
1611
1612 // CR 6300358 (sub-CR 2137150)
1613 // Most callers of this method assume that it can't return null but a
1614 // thread may not have a name whilst it is in the process of attaching to
1615 // the VM - see CR 6412693, and there are places where a JavaThread can be
1616 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1617 // if vm exit occurs during initialization). These cases can all be accounted
1618 // for such that this method never returns null.
1619 const char* JavaThread::name() const {
1620 if (Thread::is_JavaThread_protected(/* target */ this)) {
1621 // The target JavaThread is protected so get_thread_name_string() is safe:
1622 return get_thread_name_string();
1623 }
1624
1625 // The target JavaThread is not protected so we return the default:
1626 return Thread::name();
1627 }
1628
1629 // Like name() but doesn't include the protection check. This must only be
1630 // called when it is known to be safe, even though the protection check can't tell
1631 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1632 const char* JavaThread::name_raw() const {
1633 return get_thread_name_string();
1634 }
1635
1636 // Returns a non-null representation of this thread's name, or a suitable
1637 // descriptive string if there is no set name.
1638 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1639 const char* name_str;
1640 #ifdef ASSERT
1641 Thread* current = Thread::current_or_null_safe();
1642 assert(current != nullptr, "cannot be called by a detached thread");
1643 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1644 // Only access threadObj() if current thread is not a JavaThread
1645 // or if it is a JavaThread that can safely access oops.
1646 #endif
1647 oop thread_obj = threadObj();
1648 if (thread_obj != nullptr) {
1649 oop name = java_lang_Thread::name(thread_obj);
1650 if (name != nullptr) {
1651 if (buf == nullptr) {
1652 name_str = java_lang_String::as_utf8_string(name);
1653 } else {
1654 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1655 }
1656 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1657 name_str = "<no-name - thread is attaching>";
1658 } else {
1659 name_str = "<un-named>";
1660 }
1661 } else {
1662 name_str = Thread::name();
1663 }
1664 #ifdef ASSERT
1665 } else {
1666 // Current JavaThread has exited...
1667 if (current == this) {
1668 // ... and is asking about itself:
1669 name_str = "<no-name - current JavaThread has exited>";
1670 } else {
1671 // ... and it can't safely determine this JavaThread's name so
1672 // use the default thread name.
1673 name_str = Thread::name();
1674 }
1675 }
1676 #endif
1677 assert(name_str != nullptr, "unexpected null thread name");
1678 return name_str;
1679 }
1680
1681 // Helper to extract the name from the thread oop for logging.
1682 const char* JavaThread::name_for(oop thread_obj) {
1683 assert(thread_obj != nullptr, "precondition");
1684 oop name = java_lang_Thread::name(thread_obj);
1685 const char* name_str;
1686 if (name != nullptr) {
1687 name_str = java_lang_String::as_utf8_string(name);
1688 } else {
1689 name_str = "<un-named>";
1690 }
1691 return name_str;
1692 }
1693
1694 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1695
1696 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1697 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1698 // Link Java Thread object <-> C++ Thread
1699
1700 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1701 // and put it into a new Handle. The Handle "thread_oop" can then
1702 // be used to pass the C++ thread object to other methods.
1703
1704 // Set the Java level thread object (jthread) field of the
1705 // new thread (a JavaThread *) to C++ thread object using the
1706 // "thread_oop" handle.
1707
1708 // Set the thread field (a JavaThread *) of the
1709 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1710
1711 Handle thread_oop(Thread::current(),
1712 JNIHandles::resolve_non_null(jni_thread));
1713 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1714 "must be initialized");
1715 set_threadOopHandles(thread_oop());
1716
1717 if (prio == NoPriority) {
1718 prio = java_lang_Thread::priority(thread_oop());
1719 assert(prio != NoPriority, "A valid priority should be present");
1720 }
1721
1722 // Push the Java priority down to the native thread; needs Threads_lock
1723 Thread::set_priority(this, prio);
1724
1725 // Add the new thread to the Threads list and set it in motion.
1726 // We must have threads lock in order to call Threads::add.
1727 // It is crucial that we do not block before the thread is
1728 // added to the Threads list for if a GC happens, then the java_thread oop
1729 // will not be visited by GC.
1730 Threads::add(this);
1731 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1732 // on a ThreadsList. We don't want to wait for the release when the
1733 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1734 // is already visible to JVM/TI via the ThreadsList.
1735 java_lang_Thread::release_set_thread(thread_oop(), this);
1736 }
1737
1738 oop JavaThread::current_park_blocker() {
1739 // Support for JSR-166 locks
1740 oop thread_oop = threadObj();
1741 if (thread_oop != nullptr) {
1742 return java_lang_Thread::park_blocker(thread_oop);
1743 }
1744 return nullptr;
1745 }
1746
1747 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1748 // This is the external format, selecting the platform or vthread
1749 // as applicable, and allowing for a native-only stack.
1750 void JavaThread::print_jni_stack() {
1751 assert(this == JavaThread::current(), "Can't print stack of other threads");
1752 if (!has_last_Java_frame()) {
1753 ResourceMark rm(this);
1754 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1755 if (buf == nullptr) {
1756 tty->print_cr("Unable to print native stack - out of memory");
1757 return;
1758 }
1759 address lastpc = nullptr;
1760 if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) {
1761 // We have printed the native stack in platform-specific code,
1762 // so nothing else to do in this case.
1763 } else {
1764 frame f = os::current_frame();
1765 VMError::print_native_stack(tty, f, this, true /*print_source_info */,
1766 -1 /* max stack */, buf, O_BUFLEN);
1767 }
1768 } else {
1769 print_active_stack_on(tty);
1770 }
1771 }
1772
1773 void JavaThread::print_stack_on(outputStream* st) {
1774 if (!has_last_Java_frame()) return;
1775
1776 Thread* current_thread = Thread::current();
1777 ResourceMark rm(current_thread);
1778 HandleMark hm(current_thread);
1779
1780 RegisterMap reg_map(this,
1781 RegisterMap::UpdateMap::include,
1782 RegisterMap::ProcessFrames::include,
1783 RegisterMap::WalkContinuation::skip);
1784 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1785 int count = 0;
1786 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1787 if (f->is_java_frame()) {
1788 javaVFrame* jvf = javaVFrame::cast(f);
1789 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1790
1791 // Print out lock information
1792 if (JavaMonitorsInStackTrace) {
1793 jvf->print_lock_info_on(st, count);
1794 }
1795 } else {
1796 // Ignore non-Java frames
1797 }
1798
1799 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1800 count++;
1801 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1802 }
1803 }
1804
1805 void JavaThread::print_vthread_stack_on(outputStream* st) {
1806 assert(is_vthread_mounted(), "Caller should have checked this");
1807 assert(has_last_Java_frame(), "must be");
1808
1809 Thread* current_thread = Thread::current();
1810 ResourceMark rm(current_thread);
1811 HandleMark hm(current_thread);
1812
1813 RegisterMap reg_map(this,
1814 RegisterMap::UpdateMap::include,
1815 RegisterMap::ProcessFrames::include,
1816 RegisterMap::WalkContinuation::include);
1817 ContinuationEntry* cont_entry = last_continuation();
1818 vframe* start_vf = last_java_vframe(®_map);
1819 int count = 0;
1820 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1821 // Watch for end of vthread stack
1822 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1823 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1824 if (cont_entry->is_virtual_thread()) {
1825 break;
1826 }
1827 cont_entry = cont_entry->parent();
1828 }
1829 if (f->is_java_frame()) {
1830 javaVFrame* jvf = javaVFrame::cast(f);
1831 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1832
1833 // Print out lock information
1834 if (JavaMonitorsInStackTrace) {
1835 jvf->print_lock_info_on(st, count);
1836 }
1837 } else {
1838 // Ignore non-Java frames
1839 }
1840
1841 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1842 count++;
1843 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1844 }
1845 }
1846
1847 void JavaThread::print_active_stack_on(outputStream* st) {
1848 if (is_vthread_mounted()) {
1849 print_vthread_stack_on(st);
1850 } else {
1851 print_stack_on(st);
1852 }
1853 }
1854
1855 #if INCLUDE_JVMTI
1856 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1857 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1858 set_jvmti_vthread(thread_oop);
1859
1860 // unbind current JvmtiThreadState from JavaThread
1861 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1862
1863 // bind new JvmtiThreadState to JavaThread
1864 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1865
1866 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1867 JvmtiThreadState::process_pending_interp_only(this);
1868
1869 return jvmti_thread_state();
1870 }
1871 #endif
1872
1873 // JVMTI PopFrame support
1874 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1875 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1876 if (in_bytes(size_in_bytes) != 0) {
1877 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1878 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1879 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1880 }
1881 }
1882
1883 void* JavaThread::popframe_preserved_args() {
1884 return _popframe_preserved_args;
1885 }
1886
1887 ByteSize JavaThread::popframe_preserved_args_size() {
1888 return in_ByteSize(_popframe_preserved_args_size);
1889 }
1890
1891 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1892 int sz = in_bytes(popframe_preserved_args_size());
1893 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1894 return in_WordSize(sz / wordSize);
1895 }
1896
1897 void JavaThread::popframe_free_preserved_args() {
1898 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1899 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1900 _popframe_preserved_args = nullptr;
1901 _popframe_preserved_args_size = 0;
1902 }
1903
1904 #ifndef PRODUCT
1905
1906 void JavaThread::trace_frames() {
1907 tty->print_cr("[Describe stack]");
1908 int frame_no = 1;
1909 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1910 tty->print(" %d. ", frame_no++);
1911 fst.current()->print_value_on(tty);
1912 tty->cr();
1913 }
1914 }
1915
1916 class PrintAndVerifyOopClosure: public OopClosure {
1917 protected:
1918 template <class T> inline void do_oop_work(T* p) {
1919 oop obj = RawAccess<>::oop_load(p);
1920 if (obj == nullptr) return;
1921 tty->print(INTPTR_FORMAT ": ", p2i(p));
1922 if (oopDesc::is_oop_or_null(obj)) {
1923 if (obj->is_objArray()) {
1924 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1925 } else {
1926 obj->print();
1927 }
1928 } else {
1929 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1930 }
1931 tty->cr();
1932 }
1933 public:
1934 virtual void do_oop(oop* p) { do_oop_work(p); }
1935 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1936 };
1937
1938 #ifdef ASSERT
1939 // Print or validate the layout of stack frames
1940 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1941 ResourceMark rm;
1942 PreserveExceptionMark pm(this);
1943 FrameValues values;
1944 int frame_no = 0;
1945 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1946 fst.current()->describe(values, ++frame_no, fst.register_map());
1947 if (depth == frame_no) break;
1948 }
1949 Continuation::describe(values);
1950 if (validate_only) {
1951 values.validate();
1952 } else {
1953 tty->print_cr("[Describe stack layout]");
1954 values.print(this);
1955 }
1956 }
1957 #endif
1958
1959 void JavaThread::trace_stack_from(vframe* start_vf) {
1960 ResourceMark rm;
1961 int vframe_no = 1;
1962 for (vframe* f = start_vf; f; f = f->sender()) {
1963 if (f->is_java_frame()) {
1964 javaVFrame::cast(f)->print_activation(vframe_no++);
1965 } else {
1966 f->print();
1967 }
1968 if (vframe_no > StackPrintLimit) {
1969 tty->print_cr("...<more frames>...");
1970 return;
1971 }
1972 }
1973 }
1974
1975
1976 void JavaThread::trace_stack() {
1977 if (!has_last_Java_frame()) return;
1978 Thread* current_thread = Thread::current();
1979 ResourceMark rm(current_thread);
1980 HandleMark hm(current_thread);
1981 RegisterMap reg_map(this,
1982 RegisterMap::UpdateMap::include,
1983 RegisterMap::ProcessFrames::include,
1984 RegisterMap::WalkContinuation::skip);
1985 trace_stack_from(last_java_vframe(®_map));
1986 }
1987
1988
1989 #endif // PRODUCT
1990
1991 // Slow-path increment of the held monitor counts. JNI locking is always
1992 // this slow-path.
1993 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
1994 #ifdef SUPPORT_MONITOR_COUNT
1995 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
1996 _held_monitor_count += i;
1997 if (jni) {
1998 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
1999 _jni_monitor_count += i;
2000 }
2001 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2002 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2003 #endif
2004 }
2005
2006 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2007 // this slow-path.
2008 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2009 #ifdef SUPPORT_MONITOR_COUNT
2010 _held_monitor_count -= i;
2011 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count);
2012 if (jni) {
2013 _jni_monitor_count -= i;
2014 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count);
2015 }
2016 // When a thread is detaching with still owned JNI monitors, the logic that releases
2017 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2018 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2019 // JNI count is directly set to zero.
2020 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2021 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2022 #endif
2023 }
2024
2025 frame JavaThread::vthread_last_frame() {
2026 assert (is_vthread_mounted(), "Virtual thread not mounted");
2027 return last_frame();
2028 }
2029
2030 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2031 const ContinuationEntry* entry = vthread_continuation();
2032 guarantee (entry != nullptr, "Not a carrier thread");
2033 frame f = entry->to_frame();
2034 if (reg_map->process_frames()) {
2035 entry->flush_stack_processing(this);
2036 }
2037 entry->update_register_map(reg_map);
2038 return f.sender(reg_map);
2039 }
2040
2041 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2042 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2043 }
2044
2045 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2046 assert(reg_map != nullptr, "a map must be given");
2047 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2048 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2049 }
2050 return nullptr;
2051 }
2052
2053 Klass* JavaThread::security_get_caller_class(int depth) {
2054 ResetNoHandleMark rnhm;
2055 HandleMark hm(Thread::current());
2056
2057 vframeStream vfst(this);
2058 vfst.security_get_caller_frame(depth);
2059 if (!vfst.at_end()) {
2060 return vfst.method()->method_holder();
2061 }
2062 return nullptr;
2063 }
2064
2065 // Internal convenience function for millisecond resolution sleeps.
2066 bool JavaThread::sleep(jlong millis) {
2067 jlong nanos;
2068 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2069 // Conversion to nanos would overflow, saturate at max
2070 nanos = max_jlong;
2071 } else {
2072 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2073 }
2074 return sleep_nanos(nanos);
2075 }
2076
2077 // java.lang.Thread.sleep support
2078 // Returns true if sleep time elapsed as expected, and false
2079 // if the thread was interrupted.
2080 bool JavaThread::sleep_nanos(jlong nanos) {
2081 assert(this == Thread::current(), "thread consistency check");
2082 assert(nanos >= 0, "nanos are in range");
2083
2084 ParkEvent * const slp = this->_SleepEvent;
2085 // Because there can be races with thread interruption sending an unpark()
2086 // to the event, we explicitly reset it here to avoid an immediate return.
2087 // The actual interrupt state will be checked before we park().
2088 slp->reset();
2089 // Thread interruption establishes a happens-before ordering in the
2090 // Java Memory Model, so we need to ensure we synchronize with the
2091 // interrupt state.
2092 OrderAccess::fence();
2093
2094 jlong prevtime = os::javaTimeNanos();
2095
2096 jlong nanos_remaining = nanos;
2097
2098 for (;;) {
2099 // interruption has precedence over timing out
2100 if (this->is_interrupted(true)) {
2101 return false;
2102 }
2103
2104 if (nanos_remaining <= 0) {
2105 return true;
2106 }
2107
2108 {
2109 ThreadBlockInVM tbivm(this);
2110 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2111 slp->park_nanos(nanos_remaining);
2112 }
2113
2114 // Update elapsed time tracking
2115 jlong newtime = os::javaTimeNanos();
2116 if (newtime - prevtime < 0) {
2117 // time moving backwards, should only happen if no monotonic clock
2118 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2119 assert(false,
2120 "unexpected time moving backwards detected in JavaThread::sleep()");
2121 } else {
2122 nanos_remaining -= (newtime - prevtime);
2123 }
2124 prevtime = newtime;
2125 }
2126 }
2127
2128 // Last thread running calls java.lang.Shutdown.shutdown()
2129 void JavaThread::invoke_shutdown_hooks() {
2130 HandleMark hm(this);
2131
2132 // We could get here with a pending exception, if so clear it now.
2133 if (this->has_pending_exception()) {
2134 this->clear_pending_exception();
2135 }
2136
2137 EXCEPTION_MARK;
2138 Klass* shutdown_klass =
2139 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2140 THREAD);
2141 if (shutdown_klass != nullptr) {
2142 // SystemDictionary::resolve_or_null will return null if there was
2143 // an exception. If we cannot load the Shutdown class, just don't
2144 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2145 // won't be run. Note that if a shutdown hook was registered,
2146 // the Shutdown class would have already been loaded
2147 // (Runtime.addShutdownHook will load it).
2148 JavaValue result(T_VOID);
2149 JavaCalls::call_static(&result,
2150 shutdown_klass,
2151 vmSymbols::shutdown_name(),
2152 vmSymbols::void_method_signature(),
2153 THREAD);
2154 }
2155 CLEAR_PENDING_EXCEPTION;
2156 }
2157
2158 #ifndef PRODUCT
2159 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2160 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2161 }
2162 #endif
2163
2164 // Helper function to create the java.lang.Thread object for a
2165 // VM-internal thread. The thread will have the given name, and be
2166 // a member of the "system" ThreadGroup.
2167 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2168 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2169
2170 // Initialize thread_oop to put it into the system threadGroup.
2171 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2172 Handle thread_group(THREAD, Universe::system_thread_group());
2173 Handle thread_oop =
2174 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2175 vmSymbols::threadgroup_string_void_signature(),
2176 thread_group,
2177 string,
2178 CHECK_NH);
2179
2180 return thread_oop;
2181 }
2182
2183 // Starts the target JavaThread as a daemon of the given priority, and
2184 // bound to the given java.lang.Thread instance.
2185 // The Threads_lock is held for the duration.
2186 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2187 Handle thread_oop, ThreadPriority prio) {
2188
2189 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2190
2191 MutexLocker mu(current, Threads_lock);
2192
2193 // Initialize the fields of the thread_oop first.
2194 if (prio != NoPriority) {
2195 java_lang_Thread::set_priority(thread_oop(), prio);
2196 // Note: we don't call os::set_priority here. Possibly we should,
2197 // else all threads should call it themselves when they first run.
2198 }
2199
2200 java_lang_Thread::set_daemon(thread_oop());
2201
2202 // Now bind the thread_oop to the target JavaThread.
2203 target->set_threadOopHandles(thread_oop());
2204
2205 Threads::add(target); // target is now visible for safepoint/handshake
2206 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2207 // on a ThreadsList. We don't want to wait for the release when the
2208 // Theads_lock is dropped when the 'mu' destructor is run since the
2209 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2210
2211 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2212 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2213 Thread::start(target);
2214 }
2215
2216 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2217 // At this point it may be possible that no osthread was created for the
2218 // JavaThread due to lack of resources. However, since this must work
2219 // for critical system threads just check and abort if this fails.
2220 if (thread->osthread() == nullptr) {
2221 // This isn't really an OOM condition, but historically this is what
2222 // we report.
2223 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2224 os::native_thread_creation_failed_msg());
2225 }
2226 }
2227
2228 void JavaThread::pretouch_stack() {
2229 // Given an established java thread stack with usable area followed by
2230 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2231 // from the current frame down to the start of the shadow zone.
2232 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2233 if (is_in_full_stack(end)) {
2234 char* p1 = (char*) alloca(1);
2235 address here = (address) &p1;
2236 if (is_in_full_stack(here) && here > end) {
2237 size_t to_alloc = here - end;
2238 char* p2 = (char*) alloca(to_alloc);
2239 log_trace(os, thread)("Pretouching thread stack for " UINTX_FORMAT ": " RANGEFMT ".",
2240 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2241 os::pretouch_memory(p2, p2 + to_alloc,
2242 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2243 }
2244 }
2245 }
2246
2247 // Deferred OopHandle release support.
2248
2249 class OopHandleList : public CHeapObj<mtInternal> {
2250 static const int _count = 4;
2251 OopHandle _handles[_count];
2252 OopHandleList* _next;
2253 int _index;
2254 public:
2255 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2256 void add(OopHandle h) {
2257 assert(_index < _count, "too many additions");
2258 _handles[_index++] = h;
2259 }
2260 ~OopHandleList() {
2261 assert(_index == _count, "usage error");
2262 for (int i = 0; i < _index; i++) {
2263 _handles[i].release(JavaThread::thread_oop_storage());
2264 }
2265 }
2266 OopHandleList* next() const { return _next; }
2267 };
2268
2269 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2270
2271 // Called by the ServiceThread to do the work of releasing
2272 // the OopHandles.
2273 void JavaThread::release_oop_handles() {
2274 OopHandleList* list;
2275 {
2276 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2277 list = _oop_handle_list;
2278 _oop_handle_list = nullptr;
2279 }
2280 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2281
2282 while (list != nullptr) {
2283 OopHandleList* l = list;
2284 list = l->next();
2285 delete l;
2286 }
2287 }
2288
2289 // Add our OopHandles for later release.
2290 void JavaThread::add_oop_handles_for_release() {
2291 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2292 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2293 new_head->add(_threadObj);
2294 new_head->add(_vthread);
2295 new_head->add(_jvmti_vthread);
2296 new_head->add(_scopedValueCache);
2297 _oop_handle_list = new_head;
2298 Service_lock->notify_all();
2299 }