1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "cds/dynamicArchive.hpp"
28 #include "ci/ciEnv.hpp"
29 #include "classfile/javaClasses.inline.hpp"
30 #include "classfile/javaThreadStatus.hpp"
31 #include "classfile/systemDictionary.hpp"
32 #include "classfile/vmClasses.hpp"
33 #include "classfile/vmSymbols.hpp"
34 #include "code/codeCache.hpp"
35 #include "code/scopeDesc.hpp"
36 #include "compiler/compileTask.hpp"
37 #include "compiler/compilerThread.hpp"
38 #include "gc/shared/oopStorage.hpp"
39 #include "gc/shared/oopStorageSet.hpp"
40 #include "gc/shared/tlab_globals.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jvm.h"
43 #include "jvmtifiles/jvmtiEnv.hpp"
44 #include "logging/log.hpp"
45 #include "logging/logAsyncWriter.hpp"
46 #include "logging/logStream.hpp"
47 #include "memory/allocation.inline.hpp"
48 #include "memory/iterator.hpp"
49 #include "memory/universe.hpp"
50 #include "oops/access.inline.hpp"
51 #include "oops/instanceKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oopHandle.inline.hpp"
55 #include "oops/verifyOopClosure.hpp"
56 #include "prims/jvm_misc.hpp"
57 #include "prims/jvmtiDeferredUpdates.hpp"
58 #include "prims/jvmtiExport.hpp"
59 #include "prims/jvmtiThreadState.inline.hpp"
60 #include "runtime/atomic.hpp"
61 #include "runtime/continuation.hpp"
62 #include "runtime/continuationEntry.inline.hpp"
63 #include "runtime/continuationHelper.inline.hpp"
64 #include "runtime/deoptimization.hpp"
65 #include "runtime/frame.inline.hpp"
66 #include "runtime/handles.inline.hpp"
67 #include "runtime/handshake.hpp"
68 #include "runtime/interfaceSupport.inline.hpp"
69 #include "runtime/java.hpp"
70 #include "runtime/javaCalls.hpp"
71 #include "runtime/javaThread.inline.hpp"
72 #include "runtime/jniHandles.inline.hpp"
73 #include "runtime/lockStack.inline.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.hpp"
76 #include "runtime/os.inline.hpp"
77 #include "runtime/osThread.hpp"
78 #include "runtime/safepoint.hpp"
79 #include "runtime/safepointMechanism.inline.hpp"
80 #include "runtime/safepointVerifiers.hpp"
81 #include "runtime/serviceThread.hpp"
82 #include "runtime/stackFrameStream.inline.hpp"
83 #include "runtime/stackWatermarkSet.hpp"
84 #include "runtime/synchronizer.hpp"
85 #include "runtime/threadCritical.hpp"
86 #include "runtime/threadSMR.inline.hpp"
87 #include "runtime/threadStatisticalInfo.hpp"
88 #include "runtime/threadWXSetters.inline.hpp"
89 #include "runtime/timer.hpp"
90 #include "runtime/timerTrace.hpp"
91 #include "runtime/vframe.inline.hpp"
92 #include "runtime/vframeArray.hpp"
93 #include "runtime/vframe_hp.hpp"
94 #include "runtime/vmThread.hpp"
95 #include "runtime/vmOperations.hpp"
96 #include "services/threadService.hpp"
97 #include "utilities/copy.hpp"
98 #include "utilities/defaultStream.hpp"
99 #include "utilities/dtrace.hpp"
100 #include "utilities/events.hpp"
101 #include "utilities/macros.hpp"
102 #include "utilities/preserveException.hpp"
103 #include "utilities/spinYield.hpp"
104 #include "utilities/vmError.hpp"
105 #if INCLUDE_JVMCI
106 #include "jvmci/jvmci.hpp"
107 #include "jvmci/jvmciEnv.hpp"
108 #endif
109 #if INCLUDE_JFR
110 #include "jfr/jfr.hpp"
111 #endif
112
113 // Set by os layer.
114 size_t JavaThread::_stack_size_at_create = 0;
115
116 #ifdef DTRACE_ENABLED
117
118 // Only bother with this argument setup if dtrace is available
119
120 #define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
121 #define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
122
123 #define DTRACE_THREAD_PROBE(probe, javathread) \
124 { \
125 ResourceMark rm(this); \
126 int len = 0; \
127 const char* name = (javathread)->name(); \
128 len = strlen(name); \
129 HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */ \
130 (char *) name, len, \
131 java_lang_Thread::thread_id((javathread)->threadObj()), \
132 (uintptr_t) (javathread)->osthread()->thread_id(), \
133 java_lang_Thread::is_daemon((javathread)->threadObj())); \
134 }
135
136 #else // ndef DTRACE_ENABLED
137
138 #define DTRACE_THREAD_PROBE(probe, javathread)
139
140 #endif // ndef DTRACE_ENABLED
141
142 void JavaThread::smr_delete() {
143 if (_on_thread_list) {
144 ThreadsSMRSupport::smr_delete(this);
145 } else {
146 delete this;
147 }
148 }
149
150 // Initialized by VMThread at vm_global_init
151 OopStorage* JavaThread::_thread_oop_storage = nullptr;
152
153 OopStorage* JavaThread::thread_oop_storage() {
154 assert(_thread_oop_storage != nullptr, "not yet initialized");
155 return _thread_oop_storage;
156 }
157
158 void JavaThread::set_threadOopHandles(oop p) {
159 assert(_thread_oop_storage != nullptr, "not yet initialized");
160 _threadObj = OopHandle(_thread_oop_storage, p);
161 _vthread = OopHandle(_thread_oop_storage, p);
162 _jvmti_vthread = OopHandle(_thread_oop_storage, p->is_a(vmClasses::BoundVirtualThread_klass()) ? p : nullptr);
163 _scopedValueCache = OopHandle(_thread_oop_storage, nullptr);
164 }
165
166 oop JavaThread::threadObj() const {
167 // Ideally we would verify the current thread is oop_safe when this is called, but as we can
168 // be called from a signal handler we would have to use Thread::current_or_null_safe(). That
169 // has overhead and also interacts poorly with GetLastError on Windows due to the use of TLS.
170 // Instead callers must verify oop safe access.
171 return _threadObj.resolve();
172 }
173
174 oop JavaThread::vthread() const {
175 return _vthread.resolve();
176 }
177
178 void JavaThread::set_vthread(oop p) {
179 assert(_thread_oop_storage != nullptr, "not yet initialized");
180 _vthread.replace(p);
181 }
182
183 oop JavaThread::jvmti_vthread() const {
184 return _jvmti_vthread.resolve();
185 }
186
187 void JavaThread::set_jvmti_vthread(oop p) {
188 assert(_thread_oop_storage != nullptr, "not yet initialized");
189 _jvmti_vthread.replace(p);
190 }
191
192 // If there is a virtual thread mounted then return vthread() oop.
193 // Otherwise, return threadObj().
194 oop JavaThread::vthread_or_thread() const {
195 oop result = vthread();
196 if (result == nullptr) {
197 result = threadObj();
198 }
199 return result;
200 }
201
202 oop JavaThread::scopedValueCache() const {
203 return _scopedValueCache.resolve();
204 }
205
206 void JavaThread::set_scopedValueCache(oop p) {
207 if (!_scopedValueCache.is_empty()) { // i.e. if the OopHandle has been allocated
208 _scopedValueCache.replace(p);
209 } else {
210 assert(p == nullptr, "not yet initialized");
211 }
212 }
213
214 void JavaThread::clear_scopedValueBindings() {
215 set_scopedValueCache(nullptr);
216 oop vthread_oop = vthread();
217 // vthread may be null here if we get a VM error during startup,
218 // before the java.lang.Thread instance has been created.
219 if (vthread_oop != nullptr) {
220 java_lang_Thread::clear_scopedValueBindings(vthread_oop);
221 }
222 }
223
224 void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
225 bool daemon, TRAPS) {
226 assert(thread_group.not_null(), "thread group should be specified");
227 assert(threadObj() == nullptr, "should only create Java thread object once");
228
229 InstanceKlass* ik = vmClasses::Thread_klass();
230 assert(ik->is_initialized(), "must be");
231 instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
232
233 // We are called from jni_AttachCurrentThread/jni_AttachCurrentThreadAsDaemon.
234 // We cannot use JavaCalls::construct_new_instance because the java.lang.Thread
235 // constructor calls Thread.current(), which must be set here.
236 java_lang_Thread::set_thread(thread_oop(), this);
237 set_threadOopHandles(thread_oop());
238
239 JavaValue result(T_VOID);
240 if (thread_name != nullptr) {
241 Handle name = java_lang_String::create_from_str(thread_name, CHECK);
242 // Thread gets assigned specified name and null target
243 JavaCalls::call_special(&result,
244 thread_oop,
245 ik,
246 vmSymbols::object_initializer_name(),
247 vmSymbols::threadgroup_string_void_signature(),
248 thread_group,
249 name,
250 CHECK);
251 } else {
252 // Thread gets assigned name "Thread-nnn" and null target
253 // (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
254 JavaCalls::call_special(&result,
255 thread_oop,
256 ik,
257 vmSymbols::object_initializer_name(),
258 vmSymbols::threadgroup_runnable_void_signature(),
259 thread_group,
260 Handle(),
261 CHECK);
262 }
263 os::set_priority(this, NormPriority);
264
265 if (daemon) {
266 java_lang_Thread::set_daemon(thread_oop());
267 }
268 }
269
270 // ======= JavaThread ========
271
272 #if INCLUDE_JVMCI
273
274 jlong* JavaThread::_jvmci_old_thread_counters;
275
276 static bool jvmci_counters_include(JavaThread* thread) {
277 return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
278 }
279
280 void JavaThread::collect_counters(jlong* array, int length) {
281 assert(length == JVMCICounterSize, "wrong value");
282 for (int i = 0; i < length; i++) {
283 array[i] = _jvmci_old_thread_counters[i];
284 }
285 for (JavaThread* tp : ThreadsListHandle()) {
286 if (jvmci_counters_include(tp)) {
287 for (int i = 0; i < length; i++) {
288 array[i] += tp->_jvmci_counters[i];
289 }
290 }
291 }
292 }
293
294 // Attempt to enlarge the array for per thread counters.
295 static jlong* resize_counters_array(jlong* old_counters, int current_size, int new_size) {
296 jlong* new_counters = NEW_C_HEAP_ARRAY_RETURN_NULL(jlong, new_size, mtJVMCI);
297 if (new_counters == nullptr) {
298 return nullptr;
299 }
300 if (old_counters == nullptr) {
301 old_counters = new_counters;
302 memset(old_counters, 0, sizeof(jlong) * new_size);
303 } else {
304 for (int i = 0; i < MIN2((int) current_size, new_size); i++) {
305 new_counters[i] = old_counters[i];
306 }
307 if (new_size > current_size) {
308 memset(new_counters + current_size, 0, sizeof(jlong) * (new_size - current_size));
309 }
310 FREE_C_HEAP_ARRAY(jlong, old_counters);
311 }
312 return new_counters;
313 }
314
315 // Attempt to enlarge the array for per thread counters.
316 bool JavaThread::resize_counters(int current_size, int new_size) {
317 jlong* new_counters = resize_counters_array(_jvmci_counters, current_size, new_size);
318 if (new_counters == nullptr) {
319 return false;
320 } else {
321 _jvmci_counters = new_counters;
322 return true;
323 }
324 }
325
326 class VM_JVMCIResizeCounters : public VM_Operation {
327 private:
328 int _new_size;
329 bool _failed;
330
331 public:
332 VM_JVMCIResizeCounters(int new_size) : _new_size(new_size), _failed(false) { }
333 VMOp_Type type() const { return VMOp_JVMCIResizeCounters; }
334 bool allow_nested_vm_operations() const { return true; }
335 void doit() {
336 // Resize the old thread counters array
337 jlong* new_counters = resize_counters_array(JavaThread::_jvmci_old_thread_counters, JVMCICounterSize, _new_size);
338 if (new_counters == nullptr) {
339 _failed = true;
340 return;
341 } else {
342 JavaThread::_jvmci_old_thread_counters = new_counters;
343 }
344
345 // Now resize each threads array
346 for (JavaThread* tp : ThreadsListHandle()) {
347 if (!tp->resize_counters(JVMCICounterSize, _new_size)) {
348 _failed = true;
349 break;
350 }
351 }
352 if (!_failed) {
353 JVMCICounterSize = _new_size;
354 }
355 }
356
357 bool failed() { return _failed; }
358 };
359
360 bool JavaThread::resize_all_jvmci_counters(int new_size) {
361 VM_JVMCIResizeCounters op(new_size);
362 VMThread::execute(&op);
363 return !op.failed();
364 }
365
366 #endif // INCLUDE_JVMCI
367
368 #ifdef ASSERT
369 // Checks safepoint allowed and clears unhandled oops at potential safepoints.
370 void JavaThread::check_possible_safepoint() {
371 if (_no_safepoint_count > 0) {
372 print_owned_locks();
373 assert(false, "Possible safepoint reached by thread that does not allow it");
374 }
375 #ifdef CHECK_UNHANDLED_OOPS
376 // Clear unhandled oops in JavaThreads so we get a crash right away.
377 clear_unhandled_oops();
378 #endif // CHECK_UNHANDLED_OOPS
379
380 // Macos/aarch64 should be in the right state for safepoint (e.g.
381 // deoptimization needs WXWrite). Crashes caused by the wrong state rarely
382 // happens in practice, making such issues hard to find and reproduce.
383 #if defined(__APPLE__) && defined(AARCH64)
384 if (AssertWXAtThreadSync) {
385 assert_wx_state(WXWrite);
386 }
387 #endif
388 }
389
390 void JavaThread::check_for_valid_safepoint_state() {
391 // Don't complain if running a debugging command.
392 if (DebuggingContext::is_enabled()) return;
393
394 // Check NoSafepointVerifier, which is implied by locks taken that can be
395 // shared with the VM thread. This makes sure that no locks with allow_vm_block
396 // are held.
397 check_possible_safepoint();
398
399 if (thread_state() != _thread_in_vm) {
400 fatal("LEAF method calling lock?");
401 }
402
403 if (GCALotAtAllSafepoints) {
404 // We could enter a safepoint here and thus have a gc
405 InterfaceSupport::check_gc_alot();
406 }
407 }
408 #endif // ASSERT
409
410 // A JavaThread is a normal Java thread
411
412 JavaThread::JavaThread(MEMFLAGS flags) :
413 Thread(flags),
414 // Initialize fields
415 _on_thread_list(false),
416 DEBUG_ONLY(_java_call_counter(0) COMMA)
417 _entry_point(nullptr),
418 _deopt_mark(nullptr),
419 _deopt_nmethod(nullptr),
420 _vframe_array_head(nullptr),
421 _vframe_array_last(nullptr),
422 _jvmti_deferred_updates(nullptr),
423 _callee_target(nullptr),
424 _vm_result(nullptr),
425 _vm_result_2(nullptr),
426
427 _current_pending_monitor(nullptr),
428 _current_pending_monitor_is_from_java(true),
429 _current_waiting_monitor(nullptr),
430 _active_handles(nullptr),
431 _free_handle_block(nullptr),
432
433 _suspend_flags(0),
434
435 _thread_state(_thread_new),
436 _saved_exception_pc(nullptr),
437 #ifdef ASSERT
438 _no_safepoint_count(0),
439 _visited_for_critical_count(false),
440 #endif
441
442 _terminated(_not_terminated),
443 _in_deopt_handler(0),
444 _doing_unsafe_access(false),
445 _do_not_unlock_if_synchronized(false),
446 #if INCLUDE_JVMTI
447 _carrier_thread_suspended(false),
448 _is_in_VTMS_transition(false),
449 _is_in_tmp_VTMS_transition(false),
450 _is_disable_suspend(false),
451 _VTMS_transition_mark(false),
452 #ifdef ASSERT
453 _is_VTMS_transition_disabler(false),
454 #endif
455 #endif
456 _jni_attach_state(_not_attaching_via_jni),
457 _is_in_internal_oome_mark(false),
458 #if INCLUDE_JVMCI
459 _pending_deoptimization(-1),
460 _pending_monitorenter(false),
461 _pending_transfer_to_interpreter(false),
462 _pending_failed_speculation(0),
463 _jvmci{nullptr},
464 _libjvmci_runtime(nullptr),
465 _jvmci_counters(nullptr),
466 _jvmci_reserved0(0),
467 _jvmci_reserved1(0),
468 _jvmci_reserved_oop0(nullptr),
469 _live_nmethod(nullptr),
470 #endif // INCLUDE_JVMCI
471
472 _exception_oop(oop()),
473 _exception_pc(0),
474 _exception_handler_pc(0),
475 _is_method_handle_return(0),
476
477 _jni_active_critical(0),
478 _pending_jni_exception_check_fn(nullptr),
479 _depth_first_number(0),
480
481 // JVMTI PopFrame support
482 _popframe_condition(popframe_inactive),
483 _frames_to_pop_failed_realloc(0),
484
485 _cont_entry(nullptr),
486 _cont_fastpath(0),
487 _cont_fastpath_thread_state(1),
488 _held_monitor_count(0),
489 _jni_monitor_count(0),
490
491 _handshake(this),
492
493 _popframe_preserved_args(nullptr),
494 _popframe_preserved_args_size(0),
495
496 _jvmti_thread_state(nullptr),
497 _interp_only_mode(0),
498 _should_post_on_exceptions_flag(JNI_FALSE),
499 _thread_stat(new ThreadStatistics()),
500
501 _parker(),
502
503 _class_to_be_initialized(nullptr),
504
505 _SleepEvent(ParkEvent::Allocate(this)),
506
507 _lock_stack(this) {
508 set_jni_functions(jni_functions());
509
510 #if INCLUDE_JVMCI
511 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
512 if (JVMCICounterSize > 0) {
513 resize_counters(0, (int) JVMCICounterSize);
514 }
515 #endif // INCLUDE_JVMCI
516
517 // Setup safepoint state info for this thread
518 ThreadSafepointState::create(this);
519
520 SafepointMechanism::initialize_header(this);
521
522 set_requires_cross_modify_fence(false);
523
524 pd_initialize();
525 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
526 }
527
528 JavaThread* JavaThread::create_attaching_thread() {
529 JavaThread* jt = new JavaThread();
530 jt->_jni_attach_state = _attaching_via_jni;
531 return jt;
532 }
533
534 // interrupt support
535
536 void JavaThread::interrupt() {
537 // All callers should have 'this' thread protected by a
538 // ThreadsListHandle so that it cannot terminate and deallocate
539 // itself.
540 debug_only(check_for_dangling_thread_pointer(this);)
541
542 // For Windows _interrupt_event
543 WINDOWS_ONLY(osthread()->set_interrupted(true);)
544
545 // For Thread.sleep
546 _SleepEvent->unpark();
547
548 // For JSR166 LockSupport.park
549 parker()->unpark();
550
551 // For ObjectMonitor and JvmtiRawMonitor
552 _ParkEvent->unpark();
553 }
554
555 bool JavaThread::is_interrupted(bool clear_interrupted) {
556 debug_only(check_for_dangling_thread_pointer(this);)
557
558 if (_threadObj.peek() == nullptr) {
559 // If there is no j.l.Thread then it is impossible to have
560 // been interrupted. We can find null during VM initialization
561 // or when a JNI thread is still in the process of attaching.
562 // In such cases this must be the current thread.
563 assert(this == Thread::current(), "invariant");
564 return false;
565 }
566
567 bool interrupted = java_lang_Thread::interrupted(threadObj());
568
569 // NOTE that since there is no "lock" around the interrupt and
570 // is_interrupted operations, there is the possibility that the
571 // interrupted flag will be "false" but that the
572 // low-level events will be in the signaled state. This is
573 // intentional. The effect of this is that Object.wait() and
574 // LockSupport.park() will appear to have a spurious wakeup, which
575 // is allowed and not harmful, and the possibility is so rare that
576 // it is not worth the added complexity to add yet another lock.
577 // For the sleep event an explicit reset is performed on entry
578 // to JavaThread::sleep, so there is no early return. It has also been
579 // recommended not to put the interrupted flag into the "event"
580 // structure because it hides the issue.
581 // Also, because there is no lock, we must only clear the interrupt
582 // state if we are going to report that we were interrupted; otherwise
583 // an interrupt that happens just after we read the field would be lost.
584 if (interrupted && clear_interrupted) {
585 assert(this == Thread::current(), "only the current thread can clear");
586 java_lang_Thread::set_interrupted(threadObj(), false);
587 WINDOWS_ONLY(osthread()->set_interrupted(false);)
588 }
589 return interrupted;
590 }
591
592 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
593 // the Java code in Object::wait which are not present in RawMonitorWait.
594 bool JavaThread::get_and_clear_interrupted() {
595 if (!is_interrupted(false)) {
596 return false;
597 }
598 oop thread_oop = vthread_or_thread();
599 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
600
601 if (!is_virtual) {
602 return is_interrupted(true);
603 }
604 // Virtual thread: clear interrupt status for both virtual and
605 // carrier threads under the interruptLock protection.
606 JavaThread* current = JavaThread::current();
607 HandleMark hm(current);
608 Handle thread_h(current, thread_oop);
609 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
610
611 // re-check the interrupt status under the interruptLock protection
612 bool interrupted = java_lang_Thread::interrupted(thread_h());
613
614 if (interrupted) {
615 assert(this == Thread::current(), "only the current thread can clear");
616 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
617 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
618 WINDOWS_ONLY(osthread()->set_interrupted(false);)
619 }
620 return interrupted;
621 }
622
623 void JavaThread::block_if_vm_exited() {
624 if (_terminated == _vm_exited) {
625 // _vm_exited is set at safepoint, and Threads_lock is never released
626 // so we will block here forever.
627 // Here we can be doing a jump from a safe state to an unsafe state without
628 // proper transition, but it happens after the final safepoint has begun so
629 // this jump won't cause any safepoint problems.
630 set_thread_state(_thread_in_vm);
631 Threads_lock->lock();
632 ShouldNotReachHere();
633 }
634 }
635
636 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MEMFLAGS flags) : JavaThread(flags) {
637 set_entry_point(entry_point);
638 // Create the native thread itself.
639 // %note runtime_23
640 os::ThreadType thr_type = os::java_thread;
641 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
642 os::java_thread;
643 os::create_thread(this, thr_type, stack_sz);
644 // The _osthread may be null here because we ran out of memory (too many threads active).
645 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
646 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
647 // the exception consists of creating the exception object & initializing it, initialization
648 // will leave the VM via a JavaCall and then all locks must be unlocked).
649 //
650 // The thread is still suspended when we reach here. Thread must be explicit started
651 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
652 // by calling Threads:add. The reason why this is not done here, is because the thread
653 // object must be fully initialized (take a look at JVM_Start)
654 }
655
656 JavaThread::~JavaThread() {
657
658 // Enqueue OopHandles for release by the service thread.
659 add_oop_handles_for_release();
660
661 // Return the sleep event to the free list
662 ParkEvent::Release(_SleepEvent);
663 _SleepEvent = nullptr;
664
665 // Free any remaining previous UnrollBlock
666 vframeArray* old_array = vframe_array_last();
667
668 if (old_array != nullptr) {
669 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
670 old_array->set_unroll_block(nullptr);
671 delete old_info;
672 delete old_array;
673 }
674
675 JvmtiDeferredUpdates* updates = deferred_updates();
676 if (updates != nullptr) {
677 // This can only happen if thread is destroyed before deoptimization occurs.
678 assert(updates->count() > 0, "Updates holder not deleted");
679 // free deferred updates.
680 delete updates;
681 set_deferred_updates(nullptr);
682 }
683
684 // All Java related clean up happens in exit
685 ThreadSafepointState::destroy(this);
686 if (_thread_stat != nullptr) delete _thread_stat;
687
688 #if INCLUDE_JVMCI
689 if (JVMCICounterSize > 0) {
690 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
691 }
692 #endif // INCLUDE_JVMCI
693 }
694
695
696 // First JavaThread specific code executed by a new Java thread.
697 void JavaThread::pre_run() {
698 // empty - see comments in run()
699 }
700
701 // The main routine called by a new Java thread. This isn't overridden
702 // by subclasses, instead different subclasses define a different "entry_point"
703 // which defines the actual logic for that kind of thread.
704 void JavaThread::run() {
705 // initialize thread-local alloc buffer related fields
706 initialize_tlab();
707
708 _stack_overflow_state.create_stack_guard_pages();
709
710 cache_global_variables();
711
712 // Thread is now sufficiently initialized to be handled by the safepoint code as being
713 // in the VM. Change thread state from _thread_new to _thread_in_vm
714 assert(this->thread_state() == _thread_new, "wrong thread state");
715 set_thread_state(_thread_in_vm);
716
717 // Before a thread is on the threads list it is always safe, so after leaving the
718 // _thread_new we should emit a instruction barrier. The distance to modified code
719 // from here is probably far enough, but this is consistent and safe.
720 OrderAccess::cross_modify_fence();
721
722 assert(JavaThread::current() == this, "sanity check");
723 assert(!Thread::current()->owns_locks(), "sanity check");
724
725 DTRACE_THREAD_PROBE(start, this);
726
727 // This operation might block. We call that after all safepoint checks for a new thread has
728 // been completed.
729 set_active_handles(JNIHandleBlock::allocate_block());
730
731 if (JvmtiExport::should_post_thread_life()) {
732 JvmtiExport::post_thread_start(this);
733
734 }
735
736 if (AlwaysPreTouchStacks) {
737 pretouch_stack();
738 }
739
740 // We call another function to do the rest so we are sure that the stack addresses used
741 // from there will be lower than the stack base just computed.
742 thread_main_inner();
743 }
744
745 void JavaThread::thread_main_inner() {
746 assert(JavaThread::current() == this, "sanity check");
747 assert(_threadObj.peek() != nullptr, "just checking");
748
749 // Execute thread entry point unless this thread has a pending exception.
750 // Note: Due to JVMTI StopThread we can have pending exceptions already!
751 if (!this->has_pending_exception()) {
752 {
753 ResourceMark rm(this);
754 this->set_native_thread_name(this->name());
755 }
756 HandleMark hm(this);
757 this->entry_point()(this, this);
758 }
759
760 DTRACE_THREAD_PROBE(stop, this);
761
762 // Cleanup is handled in post_run()
763 }
764
765 // Shared teardown for all JavaThreads
766 void JavaThread::post_run() {
767 this->exit(false);
768 this->unregister_thread_stack_with_NMT();
769 // Defer deletion to here to ensure 'this' is still referenceable in call_run
770 // for any shared tear-down.
771 this->smr_delete();
772 }
773
774 static void ensure_join(JavaThread* thread) {
775 // We do not need to grab the Threads_lock, since we are operating on ourself.
776 Handle threadObj(thread, thread->threadObj());
777 assert(threadObj.not_null(), "java thread object must exist");
778 ObjectLocker lock(threadObj, thread);
779 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
780 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
781 // Clear the native thread instance - this makes isAlive return false and allows the join()
782 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
783 // requirements.
784 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
785 java_lang_Thread::release_set_thread(threadObj(), nullptr);
786 lock.notify_all(thread);
787 // Ignore pending exception, since we are exiting anyway
788 thread->clear_pending_exception();
789 }
790
791 static bool is_daemon(oop threadObj) {
792 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
793 }
794
795 // For any new cleanup additions, please check to see if they need to be applied to
796 // cleanup_failed_attach_current_thread as well.
797 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
798 assert(this == JavaThread::current(), "thread consistency check");
799 assert(!is_exiting(), "should not be exiting or terminated already");
800
801 elapsedTimer _timer_exit_phase1;
802 elapsedTimer _timer_exit_phase2;
803 elapsedTimer _timer_exit_phase3;
804 elapsedTimer _timer_exit_phase4;
805
806 if (log_is_enabled(Debug, os, thread, timer)) {
807 _timer_exit_phase1.start();
808 }
809
810 HandleMark hm(this);
811 Handle uncaught_exception(this, this->pending_exception());
812 this->clear_pending_exception();
813 Handle threadObj(this, this->threadObj());
814 assert(threadObj.not_null(), "Java thread object should be created");
815
816 if (!destroy_vm) {
817 if (uncaught_exception.not_null()) {
818 EXCEPTION_MARK;
819 // Call method Thread.dispatchUncaughtException().
820 Klass* thread_klass = vmClasses::Thread_klass();
821 JavaValue result(T_VOID);
822 JavaCalls::call_virtual(&result,
823 threadObj, thread_klass,
824 vmSymbols::dispatchUncaughtException_name(),
825 vmSymbols::throwable_void_signature(),
826 uncaught_exception,
827 THREAD);
828 if (HAS_PENDING_EXCEPTION) {
829 ResourceMark rm(this);
830 jio_fprintf(defaultStream::error_stream(),
831 "\nException: %s thrown from the UncaughtExceptionHandler"
832 " in thread \"%s\"\n",
833 pending_exception()->klass()->external_name(),
834 name());
835 CLEAR_PENDING_EXCEPTION;
836 }
837 }
838
839 if (!is_Compiler_thread()) {
840 // We have finished executing user-defined Java code and now have to do the
841 // implementation specific clean-up by calling Thread.exit(). We prevent any
842 // asynchronous exceptions from being delivered while in Thread.exit()
843 // to ensure the clean-up is not corrupted.
844 NoAsyncExceptionDeliveryMark _no_async(this);
845
846 EXCEPTION_MARK;
847 JavaValue result(T_VOID);
848 Klass* thread_klass = vmClasses::Thread_klass();
849 JavaCalls::call_virtual(&result,
850 threadObj, thread_klass,
851 vmSymbols::exit_method_name(),
852 vmSymbols::void_method_signature(),
853 THREAD);
854 CLEAR_PENDING_EXCEPTION;
855 }
856
857 // notify JVMTI
858 if (JvmtiExport::should_post_thread_life()) {
859 JvmtiExport::post_thread_end(this);
860 }
861 } else {
862 // before_exit() has already posted JVMTI THREAD_END events
863 }
864
865 // Cleanup any pending async exception now since we cannot access oops after
866 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
867 if (has_async_exception_condition()) {
868 handshake_state()->clean_async_exception_operation();
869 }
870
871 // The careful dance between thread suspension and exit is handled here.
872 // Since we are in thread_in_vm state and suspension is done with handshakes,
873 // we can just put in the exiting state and it will be correctly handled.
874 // Also, no more async exceptions will be added to the queue after this point.
875 set_terminated(_thread_exiting);
876 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
877
878 if (log_is_enabled(Debug, os, thread, timer)) {
879 _timer_exit_phase1.stop();
880 _timer_exit_phase2.start();
881 }
882
883 // Capture daemon status before the thread is marked as terminated.
884 bool daemon = is_daemon(threadObj());
885
886 // Notify waiters on thread object. This has to be done after exit() is called
887 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
888 // group should have the destroyed bit set before waiters are notified).
889 ensure_join(this);
890 assert(!this->has_pending_exception(), "ensure_join should have cleared");
891
892 if (log_is_enabled(Debug, os, thread, timer)) {
893 _timer_exit_phase2.stop();
894 _timer_exit_phase3.start();
895 }
896 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
897 // held by this thread must be released. The spec does not distinguish
898 // between JNI-acquired and regular Java monitors. We can only see
899 // regular Java monitors here if monitor enter-exit matching is broken.
900 //
901 // ensure_join() ignores IllegalThreadStateExceptions, and so does
902 // ObjectSynchronizer::release_monitors_owned_by_thread().
903 if (exit_type == jni_detach) {
904 // Sanity check even though JNI DetachCurrentThread() would have
905 // returned JNI_ERR if there was a Java frame. JavaThread exit
906 // should be done executing Java code by the time we get here.
907 assert(!this->has_last_Java_frame(),
908 "should not have a Java frame when detaching or exiting");
909 ObjectSynchronizer::release_monitors_owned_by_thread(this);
910 assert(!this->has_pending_exception(), "release_monitors should have cleared");
911 // Check for monitor counts being out of sync.
912 assert(held_monitor_count() == jni_monitor_count(),
913 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
914 held_monitor_count(), jni_monitor_count());
915 // All in-use monitors, including JNI-locked ones, should have been released above.
916 assert(held_monitor_count() == 0, "Failed to unlock " INTX_FORMAT " object monitors",
917 held_monitor_count());
918 } else {
919 // Check for monitor counts being out of sync.
920 assert(held_monitor_count() == jni_monitor_count(),
921 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
922 held_monitor_count(), jni_monitor_count());
923 // It is possible that a terminating thread failed to unlock monitors it locked
924 // via JNI so we don't assert the count is zero.
925 }
926
927 if (CheckJNICalls && jni_monitor_count() > 0) {
928 // We would like a fatal here, but due to we never checked this before there
929 // is a lot of tests which breaks, even with an error log.
930 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
931 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
932 }
933
934 // These things needs to be done while we are still a Java Thread. Make sure that thread
935 // is in a consistent state, in case GC happens
936 JFR_ONLY(Jfr::on_thread_exit(this);)
937
938 if (active_handles() != nullptr) {
939 JNIHandleBlock* block = active_handles();
940 set_active_handles(nullptr);
941 JNIHandleBlock::release_block(block);
942 }
943
944 if (free_handle_block() != nullptr) {
945 JNIHandleBlock* block = free_handle_block();
946 set_free_handle_block(nullptr);
947 JNIHandleBlock::release_block(block);
948 }
949
950 // These have to be removed while this is still a valid thread.
951 _stack_overflow_state.remove_stack_guard_pages();
952
953 if (UseTLAB) {
954 tlab().retire();
955 }
956
957 if (JvmtiEnv::environments_might_exist()) {
958 JvmtiExport::cleanup_thread(this);
959 }
960
961 // We need to cache the thread name for logging purposes below as once
962 // we have called on_thread_detach this thread must not access any oops.
963 char* thread_name = nullptr;
964 if (log_is_enabled(Debug, os, thread, timer)) {
965 ResourceMark rm(this);
966 thread_name = os::strdup(name());
967 }
968
969 if (log_is_enabled(Info, os, thread)) {
970 ResourceMark rm(this);
971 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: " UINTX_FORMAT ").",
972 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
973 name(), os::current_thread_id());
974 }
975
976 if (log_is_enabled(Debug, os, thread, timer)) {
977 _timer_exit_phase3.stop();
978 _timer_exit_phase4.start();
979 }
980
981 #if INCLUDE_JVMCI
982 if (JVMCICounterSize > 0) {
983 if (jvmci_counters_include(this)) {
984 for (int i = 0; i < JVMCICounterSize; i++) {
985 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
986 }
987 }
988 }
989 #endif // INCLUDE_JVMCI
990
991 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
992 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
993 Threads::remove(this, daemon);
994
995 if (log_is_enabled(Debug, os, thread, timer)) {
996 _timer_exit_phase4.stop();
997 log_debug(os, thread, timer)("name='%s'"
998 ", exit-phase1=" JLONG_FORMAT
999 ", exit-phase2=" JLONG_FORMAT
1000 ", exit-phase3=" JLONG_FORMAT
1001 ", exit-phase4=" JLONG_FORMAT,
1002 thread_name,
1003 _timer_exit_phase1.milliseconds(),
1004 _timer_exit_phase2.milliseconds(),
1005 _timer_exit_phase3.milliseconds(),
1006 _timer_exit_phase4.milliseconds());
1007 os::free(thread_name);
1008 }
1009 }
1010
1011 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1012 if (active_handles() != nullptr) {
1013 JNIHandleBlock* block = active_handles();
1014 set_active_handles(nullptr);
1015 JNIHandleBlock::release_block(block);
1016 }
1017
1018 if (free_handle_block() != nullptr) {
1019 JNIHandleBlock* block = free_handle_block();
1020 set_free_handle_block(nullptr);
1021 JNIHandleBlock::release_block(block);
1022 }
1023
1024 // These have to be removed while this is still a valid thread.
1025 _stack_overflow_state.remove_stack_guard_pages();
1026
1027 if (UseTLAB) {
1028 tlab().retire();
1029 }
1030
1031 Threads::remove(this, is_daemon);
1032 this->smr_delete();
1033 }
1034
1035 JavaThread* JavaThread::active() {
1036 Thread* thread = Thread::current();
1037 if (thread->is_Java_thread()) {
1038 return JavaThread::cast(thread);
1039 } else {
1040 assert(thread->is_VM_thread(), "this must be a vm thread");
1041 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1042 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1043 return ret;
1044 }
1045 }
1046
1047 bool JavaThread::is_lock_owned(address adr) const {
1048 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1049 return is_in_full_stack(adr);
1050 }
1051
1052 oop JavaThread::exception_oop() const {
1053 return Atomic::load(&_exception_oop);
1054 }
1055
1056 void JavaThread::set_exception_oop(oop o) {
1057 Atomic::store(&_exception_oop, o);
1058 }
1059
1060 void JavaThread::handle_special_runtime_exit_condition() {
1061 if (is_obj_deopt_suspend()) {
1062 frame_anchor()->make_walkable();
1063 wait_for_object_deoptimization();
1064 }
1065 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1066 }
1067
1068
1069 // Asynchronous exceptions support
1070 //
1071 void JavaThread::handle_async_exception(oop java_throwable) {
1072 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1073 assert(!is_at_poll_safepoint(), "should have never called this method");
1074
1075 if (has_last_Java_frame()) {
1076 frame f = last_frame();
1077 if (f.is_runtime_frame()) {
1078 // If the topmost frame is a runtime stub, then we are calling into
1079 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1080 // must deoptimize the caller before continuing, as the compiled exception
1081 // handler table may not be valid.
1082 RegisterMap reg_map(this,
1083 RegisterMap::UpdateMap::skip,
1084 RegisterMap::ProcessFrames::include,
1085 RegisterMap::WalkContinuation::skip);
1086 frame compiled_frame = f.sender(®_map);
1087 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1088 Deoptimization::deoptimize(this, compiled_frame);
1089 }
1090 }
1091 }
1092
1093 // We cannot call Exceptions::_throw(...) here because we cannot block
1094 set_pending_exception(java_throwable, __FILE__, __LINE__);
1095
1096 clear_scopedValueBindings();
1097
1098 LogTarget(Info, exceptions) lt;
1099 if (lt.is_enabled()) {
1100 ResourceMark rm;
1101 LogStream ls(lt);
1102 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1103 if (has_last_Java_frame()) {
1104 frame f = last_frame();
1105 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1106 }
1107 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1108 }
1109 }
1110
1111 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1112 // Do not throw asynchronous exceptions against the compiler thread
1113 // or if the thread is already exiting.
1114 if (!can_call_java() || is_exiting()) {
1115 delete aeh;
1116 return;
1117 }
1118
1119 oop exception = aeh->exception();
1120 Handshake::execute(aeh, this); // Install asynchronous handshake
1121
1122 ResourceMark rm;
1123 if (log_is_enabled(Info, exceptions)) {
1124 log_info(exceptions)("Pending Async. exception installed of type: %s",
1125 InstanceKlass::cast(exception->klass())->external_name());
1126 }
1127 // for AbortVMOnException flag
1128 Exceptions::debug_check_abort(exception->klass()->external_name());
1129
1130 oop vt_oop = vthread();
1131 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1132 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1133 java_lang_Thread::set_interrupted(threadObj(), true);
1134 this->interrupt();
1135 }
1136 }
1137
1138 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1139 AsyncExceptionHandshake* _aeh;
1140 public:
1141 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1142 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1143 ~InstallAsyncExceptionHandshake() {
1144 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1145 delete _aeh;
1146 }
1147 void do_thread(Thread* thr) {
1148 JavaThread* target = JavaThread::cast(thr);
1149 target->install_async_exception(_aeh);
1150 _aeh = nullptr;
1151 }
1152 };
1153
1154 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1155 OopHandle e(Universe::vm_global(), java_throwable);
1156 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1157 Handshake::execute(&iaeh, target);
1158 }
1159
1160 #if INCLUDE_JVMTI
1161 void JavaThread::set_is_in_VTMS_transition(bool val) {
1162 _is_in_VTMS_transition = val;
1163 }
1164
1165 #ifdef ASSERT
1166 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1167 _is_VTMS_transition_disabler = val;
1168 }
1169 #endif
1170 #endif
1171
1172 // External suspension mechanism.
1173 //
1174 // Guarantees on return (for a valid target thread):
1175 // - Target thread will not execute any new bytecode.
1176 // - Target thread will not enter any new monitors.
1177 //
1178 bool JavaThread::java_suspend() {
1179 #if INCLUDE_JVMTI
1180 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1181 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1182 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1183 #endif
1184
1185 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1186 "target JavaThread is not protected in calling context.");
1187 return this->handshake_state()->suspend();
1188 }
1189
1190 bool JavaThread::java_resume() {
1191 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1192 "missing ThreadsListHandle in calling context.");
1193 return this->handshake_state()->resume();
1194 }
1195
1196 // Wait for another thread to perform object reallocation and relocking on behalf of
1197 // this thread. The current thread is required to change to _thread_blocked in order
1198 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1199 // handshake safe, the other thread can complete the handshake used to synchronize
1200 // with this thread and then perform the reallocation and relocking.
1201 // See EscapeBarrier::sync_and_suspend_*()
1202
1203 void JavaThread::wait_for_object_deoptimization() {
1204 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1205 assert(this == Thread::current(), "invariant");
1206
1207 bool spin_wait = os::is_MP();
1208 do {
1209 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1210 // Wait for object deoptimization if requested.
1211 if (spin_wait) {
1212 // A single deoptimization is typically very short. Microbenchmarks
1213 // showed 5% better performance when spinning.
1214 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1215 SpinYield spin(spin_limit);
1216 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1217 spin.wait();
1218 }
1219 // Spin just once
1220 spin_wait = false;
1221 } else {
1222 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1223 if (is_obj_deopt_suspend()) {
1224 ml.wait();
1225 }
1226 }
1227 // A handshake for obj. deoptimization suspend could have been processed so
1228 // we must check after processing.
1229 } while (is_obj_deopt_suspend());
1230 }
1231
1232 #ifdef ASSERT
1233 // Verify the JavaThread has not yet been published in the Threads::list, and
1234 // hence doesn't need protection from concurrent access at this stage.
1235 void JavaThread::verify_not_published() {
1236 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1237 // since an unpublished JavaThread doesn't participate in the
1238 // Thread-SMR protocol for keeping a ThreadsList alive.
1239 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1240 }
1241 #endif
1242
1243 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1244 // pending, when _suspend_flags is non-zero or when we need to process a stack
1245 // watermark. Also check for pending async exceptions (except unsafe access error).
1246 // Note only the native==>Java barriers can call this function when thread state
1247 // is _thread_in_native_trans.
1248 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1249 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1250 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1251
1252 thread->set_thread_state(_thread_in_vm);
1253
1254 // Enable WXWrite: called directly from interpreter native wrapper.
1255 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1256
1257 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1258
1259 // After returning from native, it could be that the stack frames are not
1260 // yet safe to use. We catch such situations in the subsequent stack watermark
1261 // barrier, which will trap unsafe stack frames.
1262 StackWatermarkSet::before_unwind(thread);
1263 }
1264
1265 #ifndef PRODUCT
1266 // Deoptimization
1267 // Function for testing deoptimization
1268 void JavaThread::deoptimize() {
1269 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1270 bool deopt = false; // Dump stack only if a deopt actually happens.
1271 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1272 // Iterate over all frames in the thread and deoptimize
1273 for (; !fst.is_done(); fst.next()) {
1274 if (fst.current()->can_be_deoptimized()) {
1275
1276 if (only_at) {
1277 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1278 // consists of comma or carriage return separated numbers so
1279 // search for the current bci in that string.
1280 address pc = fst.current()->pc();
1281 nmethod* nm = fst.current()->cb()->as_nmethod();
1282 ScopeDesc* sd = nm->scope_desc_at(pc);
1283 char buffer[8];
1284 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1285 size_t len = strlen(buffer);
1286 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1287 while (found != nullptr) {
1288 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1289 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1290 // Check that the bci found is bracketed by terminators.
1291 break;
1292 }
1293 found = strstr(found + 1, buffer);
1294 }
1295 if (!found) {
1296 continue;
1297 }
1298 }
1299
1300 if (DebugDeoptimization && !deopt) {
1301 deopt = true; // One-time only print before deopt
1302 tty->print_cr("[BEFORE Deoptimization]");
1303 trace_frames();
1304 trace_stack();
1305 }
1306 Deoptimization::deoptimize(this, *fst.current());
1307 }
1308 }
1309
1310 if (DebugDeoptimization && deopt) {
1311 tty->print_cr("[AFTER Deoptimization]");
1312 trace_frames();
1313 }
1314 }
1315
1316
1317 // Make zombies
1318 void JavaThread::make_zombies() {
1319 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1320 if (fst.current()->can_be_deoptimized()) {
1321 // it is a Java nmethod
1322 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1323 assert(nm != nullptr, "did not find nmethod");
1324 nm->make_not_entrant();
1325 }
1326 }
1327 }
1328 #endif // PRODUCT
1329
1330
1331 void JavaThread::deoptimize_marked_methods() {
1332 if (!has_last_Java_frame()) return;
1333 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1334 for (; !fst.is_done(); fst.next()) {
1335 if (fst.current()->should_be_deoptimized()) {
1336 Deoptimization::deoptimize(this, *fst.current());
1337 }
1338 }
1339 }
1340
1341 #ifdef ASSERT
1342 void JavaThread::verify_frame_info() {
1343 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1344 (has_last_Java_frame() && java_call_counter() > 0),
1345 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1346 has_last_Java_frame() ? "true" : "false", java_call_counter());
1347 }
1348 #endif
1349
1350 // Push on a new block of JNI handles.
1351 void JavaThread::push_jni_handle_block() {
1352 // Allocate a new block for JNI handles.
1353 // Inlined code from jni_PushLocalFrame()
1354 JNIHandleBlock* old_handles = active_handles();
1355 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1356 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1357 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1358 set_active_handles(new_handles);
1359 }
1360
1361 // Pop off the current block of JNI handles.
1362 void JavaThread::pop_jni_handle_block() {
1363 // Release our JNI handle block
1364 JNIHandleBlock* old_handles = active_handles();
1365 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1366 assert(new_handles != nullptr, "should never set active handles to null");
1367 set_active_handles(new_handles);
1368 old_handles->set_pop_frame_link(nullptr);
1369 JNIHandleBlock::release_block(old_handles, this);
1370 }
1371
1372 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1373 // Verify that the deferred card marks have been flushed.
1374 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1375
1376 // Traverse the GCHandles
1377 Thread::oops_do_no_frames(f, cf);
1378
1379 if (active_handles() != nullptr) {
1380 active_handles()->oops_do(f);
1381 }
1382
1383 DEBUG_ONLY(verify_frame_info();)
1384
1385 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1386 // If we have deferred set_locals there might be oops waiting to be
1387 // written
1388 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1389 if (list != nullptr) {
1390 for (int i = 0; i < list->length(); i++) {
1391 list->at(i)->oops_do(f);
1392 }
1393 }
1394
1395 // Traverse instance variables at the end since the GC may be moving things
1396 // around using this function
1397 f->do_oop((oop*) &_vm_result);
1398 f->do_oop((oop*) &_exception_oop);
1399 #if INCLUDE_JVMCI
1400 f->do_oop((oop*) &_jvmci_reserved_oop0);
1401
1402 if (_live_nmethod != nullptr && cf != nullptr) {
1403 cf->do_nmethod(_live_nmethod);
1404 }
1405 #endif
1406
1407 if (jvmti_thread_state() != nullptr) {
1408 jvmti_thread_state()->oops_do(f, cf);
1409 }
1410
1411 // The continuation oops are really on the stack. But there is typically at most
1412 // one of those per thread, so we handle them here in the oops_do_no_frames part
1413 // so that we don't have to sprinkle as many stack watermark checks where these
1414 // oops are used. We just need to make sure the thread has started processing.
1415 ContinuationEntry* entry = _cont_entry;
1416 while (entry != nullptr) {
1417 f->do_oop((oop*)entry->cont_addr());
1418 f->do_oop((oop*)entry->chunk_addr());
1419 entry = entry->parent();
1420 }
1421
1422 if (LockingMode == LM_LIGHTWEIGHT) {
1423 lock_stack().oops_do(f);
1424 }
1425 }
1426
1427 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1428 if (!has_last_Java_frame()) {
1429 return;
1430 }
1431 // Finish any pending lazy GC activity for the frames
1432 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1433 // Traverse the execution stack
1434 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1435 fst.current()->oops_do(f, cf, fst.register_map());
1436 }
1437 }
1438
1439 #ifdef ASSERT
1440 void JavaThread::verify_states_for_handshake() {
1441 // This checks that the thread has a correct frame state during a handshake.
1442 verify_frame_info();
1443 }
1444 #endif
1445
1446 void JavaThread::nmethods_do(NMethodClosure* cf) {
1447 DEBUG_ONLY(verify_frame_info();)
1448 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1449
1450 if (has_last_Java_frame()) {
1451 // Traverse the execution stack
1452 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1453 fst.current()->nmethod_do(cf);
1454 }
1455 }
1456
1457 if (jvmti_thread_state() != nullptr) {
1458 jvmti_thread_state()->nmethods_do(cf);
1459 }
1460
1461 #if INCLUDE_JVMCI
1462 if (_live_nmethod != nullptr) {
1463 cf->do_nmethod(_live_nmethod);
1464 }
1465 #endif
1466 }
1467
1468 void JavaThread::metadata_do(MetadataClosure* f) {
1469 if (has_last_Java_frame()) {
1470 // Traverse the execution stack to call f() on the methods in the stack
1471 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1472 fst.current()->metadata_do(f);
1473 }
1474 } else if (is_Compiler_thread()) {
1475 // need to walk ciMetadata in current compile tasks to keep alive.
1476 CompilerThread* ct = (CompilerThread*)this;
1477 if (ct->env() != nullptr) {
1478 ct->env()->metadata_do(f);
1479 }
1480 CompileTask* task = ct->task();
1481 if (task != nullptr) {
1482 task->metadata_do(f);
1483 }
1484 }
1485 }
1486
1487 // Printing
1488 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1489 switch (_thread_state) {
1490 case _thread_uninitialized: return "_thread_uninitialized";
1491 case _thread_new: return "_thread_new";
1492 case _thread_new_trans: return "_thread_new_trans";
1493 case _thread_in_native: return "_thread_in_native";
1494 case _thread_in_native_trans: return "_thread_in_native_trans";
1495 case _thread_in_vm: return "_thread_in_vm";
1496 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1497 case _thread_in_Java: return "_thread_in_Java";
1498 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1499 case _thread_blocked: return "_thread_blocked";
1500 case _thread_blocked_trans: return "_thread_blocked_trans";
1501 default: return "unknown thread state";
1502 }
1503 }
1504
1505 void JavaThread::print_thread_state_on(outputStream *st) const {
1506 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1507 }
1508
1509 // Called by Threads::print() for VM_PrintThreads operation
1510 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1511 st->print_raw("\"");
1512 st->print_raw(name());
1513 st->print_raw("\" ");
1514 oop thread_oop = threadObj();
1515 if (thread_oop != nullptr) {
1516 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1517 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1518 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1519 }
1520 Thread::print_on(st, print_extended_info);
1521 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1522 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1523 if (thread_oop != nullptr) {
1524 if (is_vthread_mounted()) {
1525 oop vt = vthread();1526 assert(vt != nullptr, "");1527 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1528 } else {
1529 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1530 }
1531 }
1532 #ifndef PRODUCT
1533 _safepoint_state->print_on(st);
1534 #endif // PRODUCT
1535 if (is_Compiler_thread()) {
1536 CompileTask *task = ((CompilerThread*)this)->task();
1537 if (task != nullptr) {
1538 st->print(" Compiling: ");
1539 task->print(st, nullptr, true, false);
1540 } else {
1541 st->print(" No compile task");
1542 }
1543 st->cr();
1544 }
1545 }
1546
1547 void JavaThread::print() const { print_on(tty); }
1548
1549 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1550 st->print("%s", get_thread_name_string(buf, buflen));
1551 }
1552
1553 // Called by fatal error handler. The difference between this and
1554 // JavaThread::print() is that we can't grab lock or allocate memory.
1555 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1556 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1557 Thread* current = Thread::current_or_null_safe();
1558 assert(current != nullptr, "cannot be called by a detached thread");
1559 st->fill_to(60);
1560 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1561 // Only access threadObj() if current thread is not a JavaThread
1562 // or if it is a JavaThread that can safely access oops.
1563 oop thread_obj = threadObj();
1564 if (thread_obj != nullptr) {
1565 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1566 }
1567 }
1568 st->print(" [");
1569 st->print("%s", _get_thread_state_name(_thread_state));
1570 if (osthread()) {
1571 st->print(", id=%d", osthread()->thread_id());
1572 }
1573 // Use raw field members for stack base/size as this could be
1574 // called before a thread has run enough to initialize them.
1575 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1576 p2i(_stack_base - _stack_size), p2i(_stack_base),
1577 PROPERFMTARGS(_stack_size));
1578 st->print("]");
1579
1580 ThreadsSMRSupport::print_info_on(this, st);
1581 return;
1582 }
1583
1584
1585 // Verification
1586
1587 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1588 // ignore if there is no stack
1589 if (!has_last_Java_frame()) return;
1590 // traverse the stack frames. Starts from top frame.
1591 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1592 frame* fr = fst.current();
1593 f(fr, fst.register_map());
1594 }
1595 }
1596
1597 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1598
1599 void JavaThread::verify() {
1600 // Verify oops in the thread.
1601 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1602
1603 // Verify the stack frames.
1604 frames_do(frame_verify);
1605 }
1606
1607 // CR 6300358 (sub-CR 2137150)
1608 // Most callers of this method assume that it can't return null but a
1609 // thread may not have a name whilst it is in the process of attaching to
1610 // the VM - see CR 6412693, and there are places where a JavaThread can be
1611 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1612 // if vm exit occurs during initialization). These cases can all be accounted
1613 // for such that this method never returns null.
1614 const char* JavaThread::name() const {
1615 if (Thread::is_JavaThread_protected(/* target */ this)) {
1616 // The target JavaThread is protected so get_thread_name_string() is safe:
1617 return get_thread_name_string();
1618 }
1619
1620 // The target JavaThread is not protected so we return the default:
1621 return Thread::name();
1622 }
1623
1624 // Like name() but doesn't include the protection check. This must only be
1625 // called when it is known to be safe, even though the protection check can't tell
1626 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1627 const char* JavaThread::name_raw() const {
1628 return get_thread_name_string();
1629 }
1630
1631 // Returns a non-null representation of this thread's name, or a suitable
1632 // descriptive string if there is no set name.
1633 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1634 const char* name_str;
1635 #ifdef ASSERT
1636 Thread* current = Thread::current_or_null_safe();
1637 assert(current != nullptr, "cannot be called by a detached thread");
1638 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1639 // Only access threadObj() if current thread is not a JavaThread
1640 // or if it is a JavaThread that can safely access oops.
1641 #endif
1642 oop thread_obj = threadObj();
1643 if (thread_obj != nullptr) {
1644 oop name = java_lang_Thread::name(thread_obj);
1645 if (name != nullptr) {
1646 if (buf == nullptr) {
1647 name_str = java_lang_String::as_utf8_string(name);
1648 } else {
1649 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1650 }
1651 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1652 name_str = "<no-name - thread is attaching>";
1653 } else {
1654 name_str = "<un-named>";
1655 }
1656 } else {
1657 name_str = Thread::name();
1658 }
1659 #ifdef ASSERT
1660 } else {
1661 // Current JavaThread has exited...
1662 if (current == this) {
1663 // ... and is asking about itself:
1664 name_str = "<no-name - current JavaThread has exited>";
1665 } else {
1666 // ... and it can't safely determine this JavaThread's name so
1667 // use the default thread name.
1668 name_str = Thread::name();
1669 }
1670 }
1671 #endif
1672 assert(name_str != nullptr, "unexpected null thread name");
1673 return name_str;
1674 }
1675
1676 // Helper to extract the name from the thread oop for logging.
1677 const char* JavaThread::name_for(oop thread_obj) {
1678 assert(thread_obj != nullptr, "precondition");
1679 oop name = java_lang_Thread::name(thread_obj);
1680 const char* name_str;
1681 if (name != nullptr) {
1682 name_str = java_lang_String::as_utf8_string(name);
1683 } else {
1684 name_str = "<un-named>";
1685 }
1686 return name_str;
1687 }
1688
1689 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1690
1691 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1692 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1693 // Link Java Thread object <-> C++ Thread
1694
1695 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1696 // and put it into a new Handle. The Handle "thread_oop" can then
1697 // be used to pass the C++ thread object to other methods.
1698
1699 // Set the Java level thread object (jthread) field of the
1700 // new thread (a JavaThread *) to C++ thread object using the
1701 // "thread_oop" handle.
1702
1703 // Set the thread field (a JavaThread *) of the
1704 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1705
1706 Handle thread_oop(Thread::current(),
1707 JNIHandles::resolve_non_null(jni_thread));
1708 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1709 "must be initialized");
1710 set_threadOopHandles(thread_oop());
1711
1712 if (prio == NoPriority) {
1713 prio = java_lang_Thread::priority(thread_oop());
1714 assert(prio != NoPriority, "A valid priority should be present");
1715 }
1716
1717 // Push the Java priority down to the native thread; needs Threads_lock
1718 Thread::set_priority(this, prio);
1719
1720 // Add the new thread to the Threads list and set it in motion.
1721 // We must have threads lock in order to call Threads::add.
1722 // It is crucial that we do not block before the thread is
1723 // added to the Threads list for if a GC happens, then the java_thread oop
1724 // will not be visited by GC.
1725 Threads::add(this);
1726 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1727 // on a ThreadsList. We don't want to wait for the release when the
1728 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1729 // is already visible to JVM/TI via the ThreadsList.
1730 java_lang_Thread::release_set_thread(thread_oop(), this);
1731 }
1732
1733 oop JavaThread::current_park_blocker() {
1734 // Support for JSR-166 locks
1735 oop thread_oop = threadObj();
1736 if (thread_oop != nullptr) {
1737 return java_lang_Thread::park_blocker(thread_oop);
1738 }
1739 return nullptr;
1740 }
1741
1742 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1743 // This is the external format, selecting the platform or vthread
1744 // as applicable, and allowing for a native-only stack.
1745 void JavaThread::print_jni_stack() {
1746 assert(this == JavaThread::current(), "Can't print stack of other threads");
1747 if (!has_last_Java_frame()) {
1748 ResourceMark rm(this);
1749 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1750 if (buf == nullptr) {
1751 tty->print_cr("Unable to print native stack - out of memory");
1752 return;
1753 }
1754 address lastpc = nullptr;
1755 if (os::platform_print_native_stack(tty, nullptr, buf, O_BUFLEN, lastpc)) {
1756 // We have printed the native stack in platform-specific code,
1757 // so nothing else to do in this case.
1758 } else {
1759 frame f = os::current_frame();
1760 VMError::print_native_stack(tty, f, this, true /*print_source_info */,
1761 -1 /* max stack */, buf, O_BUFLEN);
1762 }
1763 } else {
1764 print_active_stack_on(tty);
1765 }
1766 }
1767
1768 void JavaThread::print_stack_on(outputStream* st) {
1769 if (!has_last_Java_frame()) return;
1770
1771 Thread* current_thread = Thread::current();
1772 ResourceMark rm(current_thread);
1773 HandleMark hm(current_thread);
1774
1775 RegisterMap reg_map(this,
1776 RegisterMap::UpdateMap::include,
1777 RegisterMap::ProcessFrames::include,
1778 RegisterMap::WalkContinuation::skip);
1779 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1780 int count = 0;
1781 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1782 if (f->is_java_frame()) {
1783 javaVFrame* jvf = javaVFrame::cast(f);
1784 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1785
1786 // Print out lock information
1787 if (JavaMonitorsInStackTrace) {
1788 jvf->print_lock_info_on(st, count);
1789 }
1790 } else {
1791 // Ignore non-Java frames
1792 }
1793
1794 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1795 count++;
1796 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1797 }
1798 }
1799
1800 void JavaThread::print_vthread_stack_on(outputStream* st) {
1801 assert(is_vthread_mounted(), "Caller should have checked this");
1802 assert(has_last_Java_frame(), "must be");
1803
1804 Thread* current_thread = Thread::current();
1805 ResourceMark rm(current_thread);
1806 HandleMark hm(current_thread);
1807
1808 RegisterMap reg_map(this,
1809 RegisterMap::UpdateMap::include,
1810 RegisterMap::ProcessFrames::include,
1811 RegisterMap::WalkContinuation::include);
1812 ContinuationEntry* cont_entry = last_continuation();
1813 vframe* start_vf = last_java_vframe(®_map);
1814 int count = 0;
1815 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1816 // Watch for end of vthread stack
1817 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1818 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1819 if (cont_entry->is_virtual_thread()) {
1820 break;
1821 }
1822 cont_entry = cont_entry->parent();
1823 }
1824 if (f->is_java_frame()) {
1825 javaVFrame* jvf = javaVFrame::cast(f);
1826 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1827
1828 // Print out lock information
1829 if (JavaMonitorsInStackTrace) {
1830 jvf->print_lock_info_on(st, count);
1831 }
1832 } else {
1833 // Ignore non-Java frames
1834 }
1835
1836 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1837 count++;
1838 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1839 }
1840 }
1841
1842 void JavaThread::print_active_stack_on(outputStream* st) {
1843 if (is_vthread_mounted()) {
1844 print_vthread_stack_on(st);
1845 } else {
1846 print_stack_on(st);
1847 }
1848 }
1849
1850 #if INCLUDE_JVMTI
1851 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1852 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1853 set_jvmti_vthread(thread_oop);
1854
1855 // unbind current JvmtiThreadState from JavaThread
1856 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1857
1858 // bind new JvmtiThreadState to JavaThread
1859 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1860
1861 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1862 JvmtiThreadState::process_pending_interp_only(this);
1863
1864 return jvmti_thread_state();
1865 }
1866 #endif
1867
1868 // JVMTI PopFrame support
1869 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1870 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1871 if (in_bytes(size_in_bytes) != 0) {
1872 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1873 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1874 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1875 }
1876 }
1877
1878 void* JavaThread::popframe_preserved_args() {
1879 return _popframe_preserved_args;
1880 }
1881
1882 ByteSize JavaThread::popframe_preserved_args_size() {
1883 return in_ByteSize(_popframe_preserved_args_size);
1884 }
1885
1886 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1887 int sz = in_bytes(popframe_preserved_args_size());
1888 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1889 return in_WordSize(sz / wordSize);
1890 }
1891
1892 void JavaThread::popframe_free_preserved_args() {
1893 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1894 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1895 _popframe_preserved_args = nullptr;
1896 _popframe_preserved_args_size = 0;
1897 }
1898
1899 #ifndef PRODUCT
1900
1901 void JavaThread::trace_frames() {
1902 tty->print_cr("[Describe stack]");
1903 int frame_no = 1;
1904 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1905 tty->print(" %d. ", frame_no++);
1906 fst.current()->print_value_on(tty, this);
1907 tty->cr();
1908 }
1909 }
1910
1911 class PrintAndVerifyOopClosure: public OopClosure {
1912 protected:
1913 template <class T> inline void do_oop_work(T* p) {
1914 oop obj = RawAccess<>::oop_load(p);
1915 if (obj == nullptr) return;
1916 tty->print(INTPTR_FORMAT ": ", p2i(p));
1917 if (oopDesc::is_oop_or_null(obj)) {
1918 if (obj->is_objArray()) {
1919 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1920 } else {
1921 obj->print();
1922 }
1923 } else {
1924 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1925 }
1926 tty->cr();
1927 }
1928 public:
1929 virtual void do_oop(oop* p) { do_oop_work(p); }
1930 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1931 };
1932
1933 #ifdef ASSERT
1934 // Print or validate the layout of stack frames
1935 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1936 ResourceMark rm;
1937 PreserveExceptionMark pm(this);
1938 FrameValues values;
1939 int frame_no = 0;
1940 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1941 fst.current()->describe(values, ++frame_no, fst.register_map());
1942 if (depth == frame_no) break;
1943 }
1944 Continuation::describe(values);
1945 if (validate_only) {
1946 values.validate();
1947 } else {
1948 tty->print_cr("[Describe stack layout]");
1949 values.print(this);
1950 }
1951 }
1952 #endif
1953
1954 void JavaThread::trace_stack_from(vframe* start_vf) {
1955 ResourceMark rm;
1956 int vframe_no = 1;
1957 for (vframe* f = start_vf; f; f = f->sender()) {
1958 if (f->is_java_frame()) {
1959 javaVFrame::cast(f)->print_activation(vframe_no++);
1960 } else {
1961 f->print();
1962 }
1963 if (vframe_no > StackPrintLimit) {
1964 tty->print_cr("...<more frames>...");
1965 return;
1966 }
1967 }
1968 }
1969
1970
1971 void JavaThread::trace_stack() {
1972 if (!has_last_Java_frame()) return;
1973 Thread* current_thread = Thread::current();
1974 ResourceMark rm(current_thread);
1975 HandleMark hm(current_thread);
1976 RegisterMap reg_map(this,
1977 RegisterMap::UpdateMap::include,
1978 RegisterMap::ProcessFrames::include,
1979 RegisterMap::WalkContinuation::skip);
1980 trace_stack_from(last_java_vframe(®_map));
1981 }
1982
1983
1984 #endif // PRODUCT
1985
1986 // Slow-path increment of the held monitor counts. JNI locking is always
1987 // this slow-path.
1988 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
1989 #ifdef SUPPORT_MONITOR_COUNT
1990 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
1991 _held_monitor_count += i;
1992 if (jni) {
1993 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
1994 _jni_monitor_count += i;
1995 }
1996 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
1997 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
1998 #endif
1999 }
2000
2001 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2002 // this slow-path.
2003 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2004 #ifdef SUPPORT_MONITOR_COUNT
2005 _held_monitor_count -= i;
2006 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count);
2007 if (jni) {
2008 _jni_monitor_count -= i;
2009 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count);
2010 }
2011 // When a thread is detaching with still owned JNI monitors, the logic that releases
2012 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2013 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2014 // JNI count is directly set to zero.
2015 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2016 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2017 #endif
2018 }
2019
2020 frame JavaThread::vthread_last_frame() {
2021 assert (is_vthread_mounted(), "Virtual thread not mounted");
2022 return last_frame();
2023 }
2024
2025 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2026 const ContinuationEntry* entry = vthread_continuation();
2027 guarantee (entry != nullptr, "Not a carrier thread");
2028 frame f = entry->to_frame();
2029 if (reg_map->process_frames()) {
2030 entry->flush_stack_processing(this);
2031 }
2032 entry->update_register_map(reg_map);
2033 return f.sender(reg_map);
2034 }
2035
2036 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2037 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2038 }
2039
2040 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2041 assert(reg_map != nullptr, "a map must be given");
2042 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2043 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2044 }
2045 return nullptr;
2046 }
2047
2048 Klass* JavaThread::security_get_caller_class(int depth) {
2049 ResetNoHandleMark rnhm;
2050 HandleMark hm(Thread::current());
2051
2052 vframeStream vfst(this);
2053 vfst.security_get_caller_frame(depth);
2054 if (!vfst.at_end()) {
2055 return vfst.method()->method_holder();
2056 }
2057 return nullptr;
2058 }
2059
2060 // Internal convenience function for millisecond resolution sleeps.
2061 bool JavaThread::sleep(jlong millis) {
2062 jlong nanos;
2063 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2064 // Conversion to nanos would overflow, saturate at max
2065 nanos = max_jlong;
2066 } else {
2067 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2068 }
2069 return sleep_nanos(nanos);
2070 }
2071
2072 // java.lang.Thread.sleep support
2073 // Returns true if sleep time elapsed as expected, and false
2074 // if the thread was interrupted.
2075 bool JavaThread::sleep_nanos(jlong nanos) {
2076 assert(this == Thread::current(), "thread consistency check");
2077 assert(nanos >= 0, "nanos are in range");
2078
2079 ParkEvent * const slp = this->_SleepEvent;
2080 // Because there can be races with thread interruption sending an unpark()
2081 // to the event, we explicitly reset it here to avoid an immediate return.
2082 // The actual interrupt state will be checked before we park().
2083 slp->reset();
2084 // Thread interruption establishes a happens-before ordering in the
2085 // Java Memory Model, so we need to ensure we synchronize with the
2086 // interrupt state.
2087 OrderAccess::fence();
2088
2089 jlong prevtime = os::javaTimeNanos();
2090
2091 jlong nanos_remaining = nanos;
2092
2093 for (;;) {
2094 // interruption has precedence over timing out
2095 if (this->is_interrupted(true)) {
2096 return false;
2097 }
2098
2099 if (nanos_remaining <= 0) {
2100 return true;
2101 }
2102
2103 {
2104 ThreadBlockInVM tbivm(this);
2105 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2106 slp->park_nanos(nanos_remaining);
2107 }
2108
2109 // Update elapsed time tracking
2110 jlong newtime = os::javaTimeNanos();
2111 if (newtime - prevtime < 0) {
2112 // time moving backwards, should only happen if no monotonic clock
2113 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2114 assert(false,
2115 "unexpected time moving backwards detected in JavaThread::sleep()");
2116 } else {
2117 nanos_remaining -= (newtime - prevtime);
2118 }
2119 prevtime = newtime;
2120 }
2121 }
2122
2123 // Last thread running calls java.lang.Shutdown.shutdown()
2124 void JavaThread::invoke_shutdown_hooks() {
2125 HandleMark hm(this);
2126
2127 // We could get here with a pending exception, if so clear it now.
2128 if (this->has_pending_exception()) {
2129 this->clear_pending_exception();
2130 }
2131
2132 EXCEPTION_MARK;
2133 Klass* shutdown_klass =
2134 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2135 THREAD);
2136 if (shutdown_klass != nullptr) {
2137 // SystemDictionary::resolve_or_null will return null if there was
2138 // an exception. If we cannot load the Shutdown class, just don't
2139 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2140 // won't be run. Note that if a shutdown hook was registered,
2141 // the Shutdown class would have already been loaded
2142 // (Runtime.addShutdownHook will load it).
2143 JavaValue result(T_VOID);
2144 JavaCalls::call_static(&result,
2145 shutdown_klass,
2146 vmSymbols::shutdown_name(),
2147 vmSymbols::void_method_signature(),
2148 THREAD);
2149 }
2150 CLEAR_PENDING_EXCEPTION;
2151 }
2152
2153 #ifndef PRODUCT
2154 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2155 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2156 }
2157 #endif
2158
2159 // Helper function to create the java.lang.Thread object for a
2160 // VM-internal thread. The thread will have the given name, and be
2161 // a member of the "system" ThreadGroup.
2162 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2163 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2164
2165 // Initialize thread_oop to put it into the system threadGroup.
2166 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2167 Handle thread_group(THREAD, Universe::system_thread_group());
2168 Handle thread_oop =
2169 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2170 vmSymbols::threadgroup_string_void_signature(),
2171 thread_group,
2172 string,
2173 CHECK_NH);
2174
2175 return thread_oop;
2176 }
2177
2178 // Starts the target JavaThread as a daemon of the given priority, and
2179 // bound to the given java.lang.Thread instance.
2180 // The Threads_lock is held for the duration.
2181 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2182 Handle thread_oop, ThreadPriority prio) {
2183
2184 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2185
2186 MutexLocker mu(current, Threads_lock);
2187
2188 // Initialize the fields of the thread_oop first.
2189 if (prio != NoPriority) {
2190 java_lang_Thread::set_priority(thread_oop(), prio);
2191 // Note: we don't call os::set_priority here. Possibly we should,
2192 // else all threads should call it themselves when they first run.
2193 }
2194
2195 java_lang_Thread::set_daemon(thread_oop());
2196
2197 // Now bind the thread_oop to the target JavaThread.
2198 target->set_threadOopHandles(thread_oop());
2199
2200 Threads::add(target); // target is now visible for safepoint/handshake
2201 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2202 // on a ThreadsList. We don't want to wait for the release when the
2203 // Theads_lock is dropped when the 'mu' destructor is run since the
2204 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2205
2206 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2207 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2208 Thread::start(target);
2209 }
2210
2211 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2212 // At this point it may be possible that no osthread was created for the
2213 // JavaThread due to lack of resources. However, since this must work
2214 // for critical system threads just check and abort if this fails.
2215 if (thread->osthread() == nullptr) {
2216 // This isn't really an OOM condition, but historically this is what
2217 // we report.
2218 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2219 os::native_thread_creation_failed_msg());
2220 }
2221 }
2222
2223 void JavaThread::pretouch_stack() {
2224 // Given an established java thread stack with usable area followed by
2225 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2226 // from the current frame down to the start of the shadow zone.
2227 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2228 if (is_in_full_stack(end)) {
2229 char* p1 = (char*) alloca(1);
2230 address here = (address) &p1;
2231 if (is_in_full_stack(here) && here > end) {
2232 size_t to_alloc = here - end;
2233 char* p2 = (char*) alloca(to_alloc);
2234 log_trace(os, thread)("Pretouching thread stack for " UINTX_FORMAT ": " RANGEFMT ".",
2235 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2236 os::pretouch_memory(p2, p2 + to_alloc,
2237 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2238 }
2239 }
2240 }
2241
2242 // Deferred OopHandle release support.
2243
2244 class OopHandleList : public CHeapObj<mtInternal> {
2245 static const int _count = 4;
2246 OopHandle _handles[_count];
2247 OopHandleList* _next;
2248 int _index;
2249 public:
2250 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2251 void add(OopHandle h) {
2252 assert(_index < _count, "too many additions");
2253 _handles[_index++] = h;
2254 }
2255 ~OopHandleList() {
2256 assert(_index == _count, "usage error");
2257 for (int i = 0; i < _index; i++) {
2258 _handles[i].release(JavaThread::thread_oop_storage());
2259 }
2260 }
2261 OopHandleList* next() const { return _next; }
2262 };
2263
2264 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2265
2266 // Called by the ServiceThread to do the work of releasing
2267 // the OopHandles.
2268 void JavaThread::release_oop_handles() {
2269 OopHandleList* list;
2270 {
2271 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2272 list = _oop_handle_list;
2273 _oop_handle_list = nullptr;
2274 }
2275 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2276
2277 while (list != nullptr) {
2278 OopHandleList* l = list;
2279 list = l->next();
2280 delete l;
2281 }
2282 }
2283
2284 // Add our OopHandles for later release.
2285 void JavaThread::add_oop_handles_for_release() {
2286 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2287 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2288 new_head->add(_threadObj);
2289 new_head->add(_vthread);
2290 new_head->add(_jvmti_vthread);
2291 new_head->add(_scopedValueCache);
2292 _oop_handle_list = new_head;
2293 Service_lock->notify_all();
2294 }
--- EOF ---