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