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