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(MemTag mem_tag) :
413 Thread(mem_tag),
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(nullptr),
474 _exception_handler_pc(nullptr),
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(nullptr),
487 _cont_fastpath_thread_state(1),
488 _held_monitor_count(0),
489 _jni_monitor_count(0),
490 _unlocked_inflated_monitor(nullptr),
491
492 _can_call_java(true),
493
494 _handshake(this),
495
496 _popframe_preserved_args(nullptr),
497 _popframe_preserved_args_size(0),
498
499 _jvmti_thread_state(nullptr),
500 _interp_only_mode(0),
501 _should_post_on_exceptions_flag(JNI_FALSE),
502 _thread_stat(new ThreadStatistics()),
503
504 _parker(),
505
506 _class_to_be_initialized(nullptr),
507 _class_being_initialized(nullptr),
508
509 _SleepEvent(ParkEvent::Allocate(this)),
510
511 _lock_stack(this),
512 _om_cache(this) {
513 set_jni_functions(jni_functions());
514
515 #if INCLUDE_JVMCI
516 assert(_jvmci._implicit_exception_pc == nullptr, "must be");
517 if (JVMCICounterSize > 0) {
518 resize_counters(0, (int) JVMCICounterSize);
519 }
520 #endif // INCLUDE_JVMCI
521
522 // Setup safepoint state info for this thread
523 ThreadSafepointState::create(this);
524
525 SafepointMechanism::initialize_header(this);
526
527 set_requires_cross_modify_fence(false);
528
529 pd_initialize();
530 assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
531 }
532
533 JavaThread* JavaThread::create_attaching_thread() {
534 JavaThread* jt = new JavaThread();
535 jt->_jni_attach_state = _attaching_via_jni;
536 return jt;
537 }
538
539 // interrupt support
540
541 void JavaThread::interrupt() {
542 // All callers should have 'this' thread protected by a
543 // ThreadsListHandle so that it cannot terminate and deallocate
544 // itself.
545 debug_only(check_for_dangling_thread_pointer(this);)
546
547 // For Windows _interrupt_event
548 WINDOWS_ONLY(osthread()->set_interrupted(true);)
549
550 // For Thread.sleep
551 _SleepEvent->unpark();
552
553 // For JSR166 LockSupport.park
554 parker()->unpark();
555
556 // For ObjectMonitor and JvmtiRawMonitor
557 _ParkEvent->unpark();
558 }
559
560 bool JavaThread::is_interrupted(bool clear_interrupted) {
561 debug_only(check_for_dangling_thread_pointer(this);)
562
563 if (_threadObj.peek() == nullptr) {
564 // If there is no j.l.Thread then it is impossible to have
565 // been interrupted. We can find null during VM initialization
566 // or when a JNI thread is still in the process of attaching.
567 // In such cases this must be the current thread.
568 assert(this == Thread::current(), "invariant");
569 return false;
570 }
571
572 bool interrupted = java_lang_Thread::interrupted(threadObj());
573
574 // NOTE that since there is no "lock" around the interrupt and
575 // is_interrupted operations, there is the possibility that the
576 // interrupted flag will be "false" but that the
577 // low-level events will be in the signaled state. This is
578 // intentional. The effect of this is that Object.wait() and
579 // LockSupport.park() will appear to have a spurious wakeup, which
580 // is allowed and not harmful, and the possibility is so rare that
581 // it is not worth the added complexity to add yet another lock.
582 // For the sleep event an explicit reset is performed on entry
583 // to JavaThread::sleep, so there is no early return. It has also been
584 // recommended not to put the interrupted flag into the "event"
585 // structure because it hides the issue.
586 // Also, because there is no lock, we must only clear the interrupt
587 // state if we are going to report that we were interrupted; otherwise
588 // an interrupt that happens just after we read the field would be lost.
589 if (interrupted && clear_interrupted) {
590 assert(this == Thread::current(), "only the current thread can clear");
591 java_lang_Thread::set_interrupted(threadObj(), false);
592 WINDOWS_ONLY(osthread()->set_interrupted(false);)
593 }
594 return interrupted;
595 }
596
597 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
598 // the Java code in Object::wait which are not present in RawMonitorWait.
599 bool JavaThread::get_and_clear_interrupted() {
600 if (!is_interrupted(false)) {
601 return false;
602 }
603 oop thread_oop = vthread_or_thread();
604 bool is_virtual = java_lang_VirtualThread::is_instance(thread_oop);
605
606 if (!is_virtual) {
607 return is_interrupted(true);
608 }
609 // Virtual thread: clear interrupt status for both virtual and
610 // carrier threads under the interruptLock protection.
611 JavaThread* current = JavaThread::current();
612 HandleMark hm(current);
613 Handle thread_h(current, thread_oop);
614 ObjectLocker lock(Handle(current, java_lang_Thread::interrupt_lock(thread_h())), current);
615
616 // re-check the interrupt status under the interruptLock protection
617 bool interrupted = java_lang_Thread::interrupted(thread_h());
618
619 if (interrupted) {
620 assert(this == Thread::current(), "only the current thread can clear");
621 java_lang_Thread::set_interrupted(thread_h(), false); // clear for virtual
622 java_lang_Thread::set_interrupted(threadObj(), false); // clear for carrier
623 WINDOWS_ONLY(osthread()->set_interrupted(false);)
624 }
625 return interrupted;
626 }
627
628 void JavaThread::block_if_vm_exited() {
629 if (_terminated == _vm_exited) {
630 // _vm_exited is set at safepoint, and Threads_lock is never released
631 // so we will block here forever.
632 // Here we can be doing a jump from a safe state to an unsafe state without
633 // proper transition, but it happens after the final safepoint has begun so
634 // this jump won't cause any safepoint problems.
635 set_thread_state(_thread_in_vm);
636 Threads_lock->lock();
637 ShouldNotReachHere();
638 }
639 }
640
641 JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz, MemTag mem_tag) : JavaThread(mem_tag) {
642 set_entry_point(entry_point);
643 // Create the native thread itself.
644 // %note runtime_23
645 os::ThreadType thr_type = os::java_thread;
646 thr_type = entry_point == &CompilerThread::thread_entry ? os::compiler_thread :
647 os::java_thread;
648 os::create_thread(this, thr_type, stack_sz);
649 // The _osthread may be null here because we ran out of memory (too many threads active).
650 // We need to throw and OutOfMemoryError - however we cannot do this here because the caller
651 // may hold a lock and all locks must be unlocked before throwing the exception (throwing
652 // the exception consists of creating the exception object & initializing it, initialization
653 // will leave the VM via a JavaCall and then all locks must be unlocked).
654 //
655 // The thread is still suspended when we reach here. Thread must be explicit started
656 // by creator! Furthermore, the thread must also explicitly be added to the Threads list
657 // by calling Threads:add. The reason why this is not done here, is because the thread
658 // object must be fully initialized (take a look at JVM_Start)
659 }
660
661 JavaThread::~JavaThread() {
662
663 // Enqueue OopHandles for release by the service thread.
664 add_oop_handles_for_release();
665
666 // Return the sleep event to the free list
667 ParkEvent::Release(_SleepEvent);
668 _SleepEvent = nullptr;
669
670 // Free any remaining previous UnrollBlock
671 vframeArray* old_array = vframe_array_last();
672
673 if (old_array != nullptr) {
674 Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
675 old_array->set_unroll_block(nullptr);
676 delete old_info;
677 delete old_array;
678 }
679
680 JvmtiDeferredUpdates* updates = deferred_updates();
681 if (updates != nullptr) {
682 // This can only happen if thread is destroyed before deoptimization occurs.
683 assert(updates->count() > 0, "Updates holder not deleted");
684 // free deferred updates.
685 delete updates;
686 set_deferred_updates(nullptr);
687 }
688
689 // All Java related clean up happens in exit
690 ThreadSafepointState::destroy(this);
691 if (_thread_stat != nullptr) delete _thread_stat;
692
693 #if INCLUDE_JVMCI
694 if (JVMCICounterSize > 0) {
695 FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
696 }
697 #endif // INCLUDE_JVMCI
698 }
699
700
701 // First JavaThread specific code executed by a new Java thread.
702 void JavaThread::pre_run() {
703 // empty - see comments in run()
704 }
705
706 // The main routine called by a new Java thread. This isn't overridden
707 // by subclasses, instead different subclasses define a different "entry_point"
708 // which defines the actual logic for that kind of thread.
709 void JavaThread::run() {
710 // initialize thread-local alloc buffer related fields
711 initialize_tlab();
712
713 _stack_overflow_state.create_stack_guard_pages();
714
715 cache_global_variables();
716
717 // Thread is now sufficiently initialized to be handled by the safepoint code as being
718 // in the VM. Change thread state from _thread_new to _thread_in_vm
719 assert(this->thread_state() == _thread_new, "wrong thread state");
720 set_thread_state(_thread_in_vm);
721
722 // Before a thread is on the threads list it is always safe, so after leaving the
723 // _thread_new we should emit a instruction barrier. The distance to modified code
724 // from here is probably far enough, but this is consistent and safe.
725 OrderAccess::cross_modify_fence();
726
727 assert(JavaThread::current() == this, "sanity check");
728 assert(!Thread::current()->owns_locks(), "sanity check");
729
730 DTRACE_THREAD_PROBE(start, this);
731
732 // This operation might block. We call that after all safepoint checks for a new thread has
733 // been completed.
734 set_active_handles(JNIHandleBlock::allocate_block());
735
736 if (JvmtiExport::should_post_thread_life()) {
737 JvmtiExport::post_thread_start(this);
738
739 }
740
741 if (AlwaysPreTouchStacks) {
742 pretouch_stack();
743 }
744
745 // We call another function to do the rest so we are sure that the stack addresses used
746 // from there will be lower than the stack base just computed.
747 thread_main_inner();
748 }
749
750 void JavaThread::thread_main_inner() {
751 assert(JavaThread::current() == this, "sanity check");
752 assert(_threadObj.peek() != nullptr, "just checking");
753
754 // Execute thread entry point unless this thread has a pending exception.
755 // Note: Due to JVMTI StopThread we can have pending exceptions already!
756 if (!this->has_pending_exception()) {
757 {
758 ResourceMark rm(this);
759 this->set_native_thread_name(this->name());
760 }
761 HandleMark hm(this);
762 this->entry_point()(this, this);
763 }
764
765 DTRACE_THREAD_PROBE(stop, this);
766
767 // Cleanup is handled in post_run()
768 }
769
770 // Shared teardown for all JavaThreads
771 void JavaThread::post_run() {
772 this->exit(false);
773 this->unregister_thread_stack_with_NMT();
774 // Defer deletion to here to ensure 'this' is still referenceable in call_run
775 // for any shared tear-down.
776 this->smr_delete();
777 }
778
779 static void ensure_join(JavaThread* thread) {
780 // We do not need to grab the Threads_lock, since we are operating on ourself.
781 Handle threadObj(thread, thread->threadObj());
782 assert(threadObj.not_null(), "java thread object must exist");
783 ObjectLocker lock(threadObj, thread);
784 // Thread is exiting. So set thread_status field in java.lang.Thread class to TERMINATED.
785 java_lang_Thread::set_thread_status(threadObj(), JavaThreadStatus::TERMINATED);
786 // Clear the native thread instance - this makes isAlive return false and allows the join()
787 // to complete once we've done the notify_all below. Needs a release() to obey Java Memory Model
788 // requirements.
789 assert(java_lang_Thread::thread(threadObj()) == thread, "must be alive");
790 java_lang_Thread::release_set_thread(threadObj(), nullptr);
791 lock.notify_all(thread);
792 // Ignore pending exception, since we are exiting anyway
793 thread->clear_pending_exception();
794 }
795
796 static bool is_daemon(oop threadObj) {
797 return (threadObj != nullptr && java_lang_Thread::is_daemon(threadObj));
798 }
799
800 // For any new cleanup additions, please check to see if they need to be applied to
801 // cleanup_failed_attach_current_thread as well.
802 void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
803 assert(this == JavaThread::current(), "thread consistency check");
804 assert(!is_exiting(), "should not be exiting or terminated already");
805
806 elapsedTimer _timer_exit_phase1;
807 elapsedTimer _timer_exit_phase2;
808 elapsedTimer _timer_exit_phase3;
809 elapsedTimer _timer_exit_phase4;
810
811 om_clear_monitor_cache();
812
813 if (log_is_enabled(Debug, os, thread, timer)) {
814 _timer_exit_phase1.start();
815 }
816
817 HandleMark hm(this);
818 Handle uncaught_exception(this, this->pending_exception());
819 this->clear_pending_exception();
820 Handle threadObj(this, this->threadObj());
821 assert(threadObj.not_null(), "Java thread object should be created");
822
823 if (!destroy_vm) {
824 if (uncaught_exception.not_null()) {
825 EXCEPTION_MARK;
826 // Call method Thread.dispatchUncaughtException().
827 Klass* thread_klass = vmClasses::Thread_klass();
828 JavaValue result(T_VOID);
829 JavaCalls::call_virtual(&result,
830 threadObj, thread_klass,
831 vmSymbols::dispatchUncaughtException_name(),
832 vmSymbols::throwable_void_signature(),
833 uncaught_exception,
834 THREAD);
835 if (HAS_PENDING_EXCEPTION) {
836 ResourceMark rm(this);
837 jio_fprintf(defaultStream::error_stream(),
838 "\nException: %s thrown from the UncaughtExceptionHandler"
839 " in thread \"%s\"\n",
840 pending_exception()->klass()->external_name(),
841 name());
842 CLEAR_PENDING_EXCEPTION;
843 }
844 }
845
846 if (!is_Compiler_thread()) {
847 // We have finished executing user-defined Java code and now have to do the
848 // implementation specific clean-up by calling Thread.exit(). We prevent any
849 // asynchronous exceptions from being delivered while in Thread.exit()
850 // to ensure the clean-up is not corrupted.
851 NoAsyncExceptionDeliveryMark _no_async(this);
852
853 EXCEPTION_MARK;
854 JavaValue result(T_VOID);
855 Klass* thread_klass = vmClasses::Thread_klass();
856 JavaCalls::call_virtual(&result,
857 threadObj, thread_klass,
858 vmSymbols::exit_method_name(),
859 vmSymbols::void_method_signature(),
860 THREAD);
861 CLEAR_PENDING_EXCEPTION;
862 }
863
864 // notify JVMTI
865 if (JvmtiExport::should_post_thread_life()) {
866 JvmtiExport::post_thread_end(this);
867 }
868 } else {
869 // before_exit() has already posted JVMTI THREAD_END events
870 }
871
872 // Cleanup any pending async exception now since we cannot access oops after
873 // BarrierSet::barrier_set()->on_thread_detach() has been executed.
874 if (has_async_exception_condition()) {
875 handshake_state()->clean_async_exception_operation();
876 }
877
878 // The careful dance between thread suspension and exit is handled here.
879 // Since we are in thread_in_vm state and suspension is done with handshakes,
880 // we can just put in the exiting state and it will be correctly handled.
881 // Also, no more async exceptions will be added to the queue after this point.
882 set_terminated(_thread_exiting);
883 ThreadService::current_thread_exiting(this, is_daemon(threadObj()));
884
885 if (log_is_enabled(Debug, os, thread, timer)) {
886 _timer_exit_phase1.stop();
887 _timer_exit_phase2.start();
888 }
889
890 // Capture daemon status before the thread is marked as terminated.
891 bool daemon = is_daemon(threadObj());
892
893 // Notify waiters on thread object. This has to be done after exit() is called
894 // on the thread (if the thread is the last thread in a daemon ThreadGroup the
895 // group should have the destroyed bit set before waiters are notified).
896 ensure_join(this);
897 assert(!this->has_pending_exception(), "ensure_join should have cleared");
898
899 if (log_is_enabled(Debug, os, thread, timer)) {
900 _timer_exit_phase2.stop();
901 _timer_exit_phase3.start();
902 }
903 // 6282335 JNI DetachCurrentThread spec states that all Java monitors
904 // held by this thread must be released. The spec does not distinguish
905 // between JNI-acquired and regular Java monitors. We can only see
906 // regular Java monitors here if monitor enter-exit matching is broken.
907 //
908 // ensure_join() ignores IllegalThreadStateExceptions, and so does
909 // ObjectSynchronizer::release_monitors_owned_by_thread().
910 if (exit_type == jni_detach) {
911 // Sanity check even though JNI DetachCurrentThread() would have
912 // returned JNI_ERR if there was a Java frame. JavaThread exit
913 // should be done executing Java code by the time we get here.
914 assert(!this->has_last_Java_frame(),
915 "should not have a Java frame when detaching or exiting");
916 ObjectSynchronizer::release_monitors_owned_by_thread(this);
917 assert(!this->has_pending_exception(), "release_monitors should have cleared");
918 // Check for monitor counts being out of sync.
919 assert(held_monitor_count() == jni_monitor_count(),
920 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
921 held_monitor_count(), jni_monitor_count());
922 // All in-use monitors, including JNI-locked ones, should have been released above.
923 assert(held_monitor_count() == 0, "Failed to unlock " INTX_FORMAT " object monitors",
924 held_monitor_count());
925 } else {
926 // Check for monitor counts being out of sync.
927 assert(held_monitor_count() == jni_monitor_count(),
928 "held monitor count should be equal to jni: " INTX_FORMAT " != " INTX_FORMAT,
929 held_monitor_count(), jni_monitor_count());
930 // It is possible that a terminating thread failed to unlock monitors it locked
931 // via JNI so we don't assert the count is zero.
932 }
933
934 if (CheckJNICalls && jni_monitor_count() > 0) {
935 // We would like a fatal here, but due to we never checked this before there
936 // is a lot of tests which breaks, even with an error log.
937 log_debug(jni)("JavaThread %s (tid: " UINTX_FORMAT ") with Objects still locked by JNI MonitorEnter.",
938 exit_type == JavaThread::normal_exit ? "exiting" : "detaching", os::current_thread_id());
939 }
940
941 // These things needs to be done while we are still a Java Thread. Make sure that thread
942 // is in a consistent state, in case GC happens
943 JFR_ONLY(Jfr::on_thread_exit(this);)
944
945 if (active_handles() != nullptr) {
946 JNIHandleBlock* block = active_handles();
947 set_active_handles(nullptr);
948 JNIHandleBlock::release_block(block);
949 }
950
951 if (free_handle_block() != nullptr) {
952 JNIHandleBlock* block = free_handle_block();
953 set_free_handle_block(nullptr);
954 JNIHandleBlock::release_block(block);
955 }
956
957 // These have to be removed while this is still a valid thread.
958 _stack_overflow_state.remove_stack_guard_pages();
959
960 if (UseTLAB) {
961 tlab().retire();
962 }
963
964 if (JvmtiEnv::environments_might_exist()) {
965 JvmtiExport::cleanup_thread(this);
966 }
967
968 // We need to cache the thread name for logging purposes below as once
969 // we have called on_thread_detach this thread must not access any oops.
970 char* thread_name = nullptr;
971 if (log_is_enabled(Debug, os, thread, timer) || (CountBytecodesPerThread && log_is_enabled(Info, init))) {
972 ResourceMark rm(this);
973 thread_name = os::strdup(name());
974 }
975
976 if (log_is_enabled(Info, os, thread)) {
977 ResourceMark rm(this);
978 log_info(os, thread)("JavaThread %s (name: \"%s\", tid: " UINTX_FORMAT ").",
979 exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
980 name(), os::current_thread_id());
981 }
982
983 if (log_is_enabled(Debug, os, thread, timer)) {
984 _timer_exit_phase3.stop();
985 _timer_exit_phase4.start();
986 }
987
988 #if INCLUDE_JVMCI
989 if (JVMCICounterSize > 0) {
990 if (jvmci_counters_include(this)) {
991 for (int i = 0; i < JVMCICounterSize; i++) {
992 _jvmci_old_thread_counters[i] += _jvmci_counters[i];
993 }
994 }
995 }
996 #endif // INCLUDE_JVMCI
997
998 if (bc_counter_value() > 0) {
999 log_info(init)("Thread '%s': " JLONG_FORMAT " bytecodes executed (during clinit: " JLONG_FORMAT ")",
1000 thread_name, bc_counter_value(), clinit_bc_counter_value());
1001 }
1002
1003 // Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread.
1004 // We call BarrierSet::barrier_set()->on_thread_detach() here so no touching of oops after this point.
1005 Threads::remove(this, daemon);
1006
1007 if (log_is_enabled(Debug, os, thread, timer)) {
1008 _timer_exit_phase4.stop();
1009 log_debug(os, thread, timer)("name='%s'"
1010 ", exit-phase1=" JLONG_FORMAT
1011 ", exit-phase2=" JLONG_FORMAT
1012 ", exit-phase3=" JLONG_FORMAT
1013 ", exit-phase4=" JLONG_FORMAT,
1014 thread_name,
1015 _timer_exit_phase1.milliseconds(),
1016 _timer_exit_phase2.milliseconds(),
1017 _timer_exit_phase3.milliseconds(),
1018 _timer_exit_phase4.milliseconds());
1019 os::free(thread_name);
1020 }
1021 }
1022
1023 void JavaThread::cleanup_failed_attach_current_thread(bool is_daemon) {
1024 if (active_handles() != nullptr) {
1025 JNIHandleBlock* block = active_handles();
1026 set_active_handles(nullptr);
1027 JNIHandleBlock::release_block(block);
1028 }
1029
1030 if (free_handle_block() != nullptr) {
1031 JNIHandleBlock* block = free_handle_block();
1032 set_free_handle_block(nullptr);
1033 JNIHandleBlock::release_block(block);
1034 }
1035
1036 // These have to be removed while this is still a valid thread.
1037 _stack_overflow_state.remove_stack_guard_pages();
1038
1039 if (UseTLAB) {
1040 tlab().retire();
1041 }
1042
1043 Threads::remove(this, is_daemon);
1044 this->smr_delete();
1045 }
1046
1047 JavaThread* JavaThread::active() {
1048 Thread* thread = Thread::current();
1049 if (thread->is_Java_thread()) {
1050 return JavaThread::cast(thread);
1051 } else {
1052 assert(thread->is_VM_thread(), "this must be a vm thread");
1053 VM_Operation* op = ((VMThread*) thread)->vm_operation();
1054 JavaThread *ret = op == nullptr ? nullptr : JavaThread::cast(op->calling_thread());
1055 return ret;
1056 }
1057 }
1058
1059 bool JavaThread::is_lock_owned(address adr) const {
1060 assert(LockingMode != LM_LIGHTWEIGHT, "should not be called with new lightweight locking");
1061 return is_in_full_stack(adr);
1062 }
1063
1064 oop JavaThread::exception_oop() const {
1065 return Atomic::load(&_exception_oop);
1066 }
1067
1068 void JavaThread::set_exception_oop(oop o) {
1069 Atomic::store(&_exception_oop, o);
1070 }
1071
1072 void JavaThread::handle_special_runtime_exit_condition() {
1073 if (is_obj_deopt_suspend()) {
1074 frame_anchor()->make_walkable();
1075 wait_for_object_deoptimization();
1076 }
1077 JFR_ONLY(SUSPEND_THREAD_CONDITIONAL(this);)
1078 }
1079
1080
1081 // Asynchronous exceptions support
1082 //
1083 void JavaThread::handle_async_exception(oop java_throwable) {
1084 assert(java_throwable != nullptr, "should have an _async_exception to throw");
1085 assert(!is_at_poll_safepoint(), "should have never called this method");
1086
1087 if (has_last_Java_frame()) {
1088 frame f = last_frame();
1089 if (f.is_runtime_frame()) {
1090 // If the topmost frame is a runtime stub, then we are calling into
1091 // OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
1092 // must deoptimize the caller before continuing, as the compiled exception
1093 // handler table may not be valid.
1094 RegisterMap reg_map(this,
1095 RegisterMap::UpdateMap::skip,
1096 RegisterMap::ProcessFrames::include,
1097 RegisterMap::WalkContinuation::skip);
1098 frame compiled_frame = f.sender(®_map);
1099 if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
1100 Deoptimization::deoptimize(this, compiled_frame);
1101 }
1102 }
1103 }
1104
1105 // We cannot call Exceptions::_throw(...) here because we cannot block
1106 set_pending_exception(java_throwable, __FILE__, __LINE__);
1107
1108 clear_scopedValueBindings();
1109
1110 LogTarget(Info, exceptions) lt;
1111 if (lt.is_enabled()) {
1112 ResourceMark rm;
1113 LogStream ls(lt);
1114 ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
1115 if (has_last_Java_frame()) {
1116 frame f = last_frame();
1117 ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
1118 }
1119 ls.print_cr(" of type: %s", java_throwable->klass()->external_name());
1120 }
1121 }
1122
1123 void JavaThread::install_async_exception(AsyncExceptionHandshake* aeh) {
1124 // Do not throw asynchronous exceptions against the compiler thread
1125 // or if the thread is already exiting.
1126 if (!can_call_java() || is_exiting()) {
1127 delete aeh;
1128 return;
1129 }
1130
1131 oop exception = aeh->exception();
1132 Handshake::execute(aeh, this); // Install asynchronous handshake
1133
1134 ResourceMark rm;
1135 if (log_is_enabled(Info, exceptions)) {
1136 log_info(exceptions)("Pending Async. exception installed of type: %s",
1137 InstanceKlass::cast(exception->klass())->external_name());
1138 }
1139 // for AbortVMOnException flag
1140 Exceptions::debug_check_abort(exception->klass()->external_name());
1141
1142 oop vt_oop = vthread();
1143 if (vt_oop == nullptr || !vt_oop->is_a(vmClasses::BaseVirtualThread_klass())) {
1144 // Interrupt thread so it will wake up from a potential wait()/sleep()/park()
1145 java_lang_Thread::set_interrupted(threadObj(), true);
1146 this->interrupt();
1147 }
1148 }
1149
1150 class InstallAsyncExceptionHandshake : public HandshakeClosure {
1151 AsyncExceptionHandshake* _aeh;
1152 public:
1153 InstallAsyncExceptionHandshake(AsyncExceptionHandshake* aeh) :
1154 HandshakeClosure("InstallAsyncException"), _aeh(aeh) {}
1155 ~InstallAsyncExceptionHandshake() {
1156 // If InstallAsyncExceptionHandshake was never executed we need to clean up _aeh.
1157 delete _aeh;
1158 }
1159 void do_thread(Thread* thr) {
1160 JavaThread* target = JavaThread::cast(thr);
1161 target->install_async_exception(_aeh);
1162 _aeh = nullptr;
1163 }
1164 };
1165
1166 void JavaThread::send_async_exception(JavaThread* target, oop java_throwable) {
1167 OopHandle e(Universe::vm_global(), java_throwable);
1168 InstallAsyncExceptionHandshake iaeh(new AsyncExceptionHandshake(e));
1169 Handshake::execute(&iaeh, target);
1170 }
1171
1172 #if INCLUDE_JVMTI
1173 void JavaThread::set_is_in_VTMS_transition(bool val) {
1174 _is_in_VTMS_transition = val;
1175 }
1176
1177 #ifdef ASSERT
1178 void JavaThread::set_is_VTMS_transition_disabler(bool val) {
1179 _is_VTMS_transition_disabler = val;
1180 }
1181 #endif
1182 #endif
1183
1184 // External suspension mechanism.
1185 //
1186 // Guarantees on return (for a valid target thread):
1187 // - Target thread will not execute any new bytecode.
1188 // - Target thread will not enter any new monitors.
1189 //
1190 bool JavaThread::java_suspend() {
1191 #if INCLUDE_JVMTI
1192 // Suspending a JavaThread in VTMS transition or disabling VTMS transitions can cause deadlocks.
1193 assert(!is_in_VTMS_transition(), "no suspend allowed in VTMS transition");
1194 assert(!is_VTMS_transition_disabler(), "no suspend allowed for VTMS transition disablers");
1195 #endif
1196
1197 guarantee(Thread::is_JavaThread_protected(/* target */ this),
1198 "target JavaThread is not protected in calling context.");
1199 return this->handshake_state()->suspend();
1200 }
1201
1202 bool JavaThread::java_resume() {
1203 guarantee(Thread::is_JavaThread_protected_by_TLH(/* target */ this),
1204 "missing ThreadsListHandle in calling context.");
1205 return this->handshake_state()->resume();
1206 }
1207
1208 // Wait for another thread to perform object reallocation and relocking on behalf of
1209 // this thread. The current thread is required to change to _thread_blocked in order
1210 // to be seen to be safepoint/handshake safe whilst suspended and only after becoming
1211 // handshake safe, the other thread can complete the handshake used to synchronize
1212 // with this thread and then perform the reallocation and relocking.
1213 // See EscapeBarrier::sync_and_suspend_*()
1214
1215 void JavaThread::wait_for_object_deoptimization() {
1216 assert(!has_last_Java_frame() || frame_anchor()->walkable(), "should have walkable stack");
1217 assert(this == Thread::current(), "invariant");
1218
1219 bool spin_wait = os::is_MP();
1220 do {
1221 ThreadBlockInVM tbivm(this, true /* allow_suspend */);
1222 // Wait for object deoptimization if requested.
1223 if (spin_wait) {
1224 // A single deoptimization is typically very short. Microbenchmarks
1225 // showed 5% better performance when spinning.
1226 const uint spin_limit = 10 * SpinYield::default_spin_limit;
1227 SpinYield spin(spin_limit);
1228 for (uint i = 0; is_obj_deopt_suspend() && i < spin_limit; i++) {
1229 spin.wait();
1230 }
1231 // Spin just once
1232 spin_wait = false;
1233 } else {
1234 MonitorLocker ml(this, EscapeBarrier_lock, Monitor::_no_safepoint_check_flag);
1235 if (is_obj_deopt_suspend()) {
1236 ml.wait();
1237 }
1238 }
1239 // A handshake for obj. deoptimization suspend could have been processed so
1240 // we must check after processing.
1241 } while (is_obj_deopt_suspend());
1242 }
1243
1244 #ifdef ASSERT
1245 // Verify the JavaThread has not yet been published in the Threads::list, and
1246 // hence doesn't need protection from concurrent access at this stage.
1247 void JavaThread::verify_not_published() {
1248 // Cannot create a ThreadsListHandle here and check !tlh.includes(this)
1249 // since an unpublished JavaThread doesn't participate in the
1250 // Thread-SMR protocol for keeping a ThreadsList alive.
1251 assert(!on_thread_list(), "JavaThread shouldn't have been published yet!");
1252 }
1253 #endif
1254
1255 // Slow path when the native==>Java barriers detect a safepoint/handshake is
1256 // pending, when _suspend_flags is non-zero or when we need to process a stack
1257 // watermark. Also check for pending async exceptions (except unsafe access error).
1258 // Note only the native==>Java barriers can call this function when thread state
1259 // is _thread_in_native_trans.
1260 void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
1261 assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
1262 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native->Java transition");
1263
1264 thread->set_thread_state(_thread_in_vm);
1265
1266 // Enable WXWrite: called directly from interpreter native wrapper.
1267 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, thread));
1268
1269 SafepointMechanism::process_if_requested_with_exit_check(thread, true /* check asyncs */);
1270
1271 // After returning from native, it could be that the stack frames are not
1272 // yet safe to use. We catch such situations in the subsequent stack watermark
1273 // barrier, which will trap unsafe stack frames.
1274 StackWatermarkSet::before_unwind(thread);
1275 }
1276
1277 #ifndef PRODUCT
1278 // Deoptimization
1279 // Function for testing deoptimization
1280 void JavaThread::deoptimize() {
1281 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1282 bool deopt = false; // Dump stack only if a deopt actually happens.
1283 bool only_at = strlen(DeoptimizeOnlyAt) > 0;
1284 // Iterate over all frames in the thread and deoptimize
1285 for (; !fst.is_done(); fst.next()) {
1286 if (fst.current()->can_be_deoptimized()) {
1287
1288 if (only_at) {
1289 // Deoptimize only at particular bcis. DeoptimizeOnlyAt
1290 // consists of comma or carriage return separated numbers so
1291 // search for the current bci in that string.
1292 address pc = fst.current()->pc();
1293 nmethod* nm = fst.current()->cb()->as_nmethod();
1294 ScopeDesc* sd = nm->scope_desc_at(pc);
1295 char buffer[8];
1296 jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
1297 size_t len = strlen(buffer);
1298 const char * found = strstr(DeoptimizeOnlyAt, buffer);
1299 while (found != nullptr) {
1300 if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
1301 (found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
1302 // Check that the bci found is bracketed by terminators.
1303 break;
1304 }
1305 found = strstr(found + 1, buffer);
1306 }
1307 if (!found) {
1308 continue;
1309 }
1310 }
1311
1312 if (DebugDeoptimization && !deopt) {
1313 deopt = true; // One-time only print before deopt
1314 tty->print_cr("[BEFORE Deoptimization]");
1315 trace_frames();
1316 trace_stack();
1317 }
1318 Deoptimization::deoptimize(this, *fst.current());
1319 }
1320 }
1321
1322 if (DebugDeoptimization && deopt) {
1323 tty->print_cr("[AFTER Deoptimization]");
1324 trace_frames();
1325 }
1326 }
1327
1328
1329 // Make zombies
1330 void JavaThread::make_zombies() {
1331 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1332 if (fst.current()->can_be_deoptimized()) {
1333 // it is a Java nmethod
1334 nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
1335 assert(nm != nullptr, "did not find nmethod");
1336 nm->make_not_entrant();
1337 }
1338 }
1339 }
1340 #endif // PRODUCT
1341
1342
1343 void JavaThread::deoptimize_marked_methods() {
1344 if (!has_last_Java_frame()) return;
1345 StackFrameStream fst(this, false /* update */, true /* process_frames */);
1346 for (; !fst.is_done(); fst.next()) {
1347 if (fst.current()->should_be_deoptimized()) {
1348 Deoptimization::deoptimize(this, *fst.current());
1349 }
1350 }
1351 }
1352
1353 #ifdef ASSERT
1354 void JavaThread::verify_frame_info() {
1355 assert((!has_last_Java_frame() && java_call_counter() == 0) ||
1356 (has_last_Java_frame() && java_call_counter() > 0),
1357 "unexpected frame info: has_last_frame=%s, java_call_counter=%d",
1358 has_last_Java_frame() ? "true" : "false", java_call_counter());
1359 }
1360 #endif
1361
1362 // Push on a new block of JNI handles.
1363 void JavaThread::push_jni_handle_block() {
1364 // Allocate a new block for JNI handles.
1365 // Inlined code from jni_PushLocalFrame()
1366 JNIHandleBlock* old_handles = active_handles();
1367 JNIHandleBlock* new_handles = JNIHandleBlock::allocate_block(this);
1368 assert(old_handles != nullptr && new_handles != nullptr, "should not be null");
1369 new_handles->set_pop_frame_link(old_handles); // make sure java handles get gc'd.
1370 set_active_handles(new_handles);
1371 }
1372
1373 // Pop off the current block of JNI handles.
1374 void JavaThread::pop_jni_handle_block() {
1375 // Release our JNI handle block
1376 JNIHandleBlock* old_handles = active_handles();
1377 JNIHandleBlock* new_handles = old_handles->pop_frame_link();
1378 assert(new_handles != nullptr, "should never set active handles to null");
1379 set_active_handles(new_handles);
1380 old_handles->set_pop_frame_link(nullptr);
1381 JNIHandleBlock::release_block(old_handles, this);
1382 }
1383
1384 void JavaThread::oops_do_no_frames(OopClosure* f, NMethodClosure* cf) {
1385 // Verify that the deferred card marks have been flushed.
1386 assert(deferred_card_mark().is_empty(), "Should be empty during GC");
1387
1388 // Traverse the GCHandles
1389 Thread::oops_do_no_frames(f, cf);
1390
1391 if (active_handles() != nullptr) {
1392 active_handles()->oops_do(f);
1393 }
1394
1395 DEBUG_ONLY(verify_frame_info();)
1396
1397 assert(vframe_array_head() == nullptr, "deopt in progress at a safepoint!");
1398 // If we have deferred set_locals there might be oops waiting to be
1399 // written
1400 GrowableArray<jvmtiDeferredLocalVariableSet*>* list = JvmtiDeferredUpdates::deferred_locals(this);
1401 if (list != nullptr) {
1402 for (int i = 0; i < list->length(); i++) {
1403 list->at(i)->oops_do(f);
1404 }
1405 }
1406
1407 // Traverse instance variables at the end since the GC may be moving things
1408 // around using this function
1409 f->do_oop((oop*) &_vm_result);
1410 f->do_oop((oop*) &_exception_oop);
1411 #if INCLUDE_JVMCI
1412 f->do_oop((oop*) &_jvmci_reserved_oop0);
1413
1414 if (_live_nmethod != nullptr && cf != nullptr) {
1415 cf->do_nmethod(_live_nmethod);
1416 }
1417 #endif
1418
1419 if (jvmti_thread_state() != nullptr) {
1420 jvmti_thread_state()->oops_do(f, cf);
1421 }
1422
1423 // The continuation oops are really on the stack. But there is typically at most
1424 // one of those per thread, so we handle them here in the oops_do_no_frames part
1425 // so that we don't have to sprinkle as many stack watermark checks where these
1426 // oops are used. We just need to make sure the thread has started processing.
1427 ContinuationEntry* entry = _cont_entry;
1428 while (entry != nullptr) {
1429 f->do_oop((oop*)entry->cont_addr());
1430 f->do_oop((oop*)entry->chunk_addr());
1431 entry = entry->parent();
1432 }
1433
1434 if (LockingMode == LM_LIGHTWEIGHT) {
1435 lock_stack().oops_do(f);
1436 }
1437 }
1438
1439 void JavaThread::oops_do_frames(OopClosure* f, NMethodClosure* cf) {
1440 if (!has_last_Java_frame()) {
1441 return;
1442 }
1443 // Finish any pending lazy GC activity for the frames
1444 StackWatermarkSet::finish_processing(this, nullptr /* context */, StackWatermarkKind::gc);
1445 // Traverse the execution stack
1446 for (StackFrameStream fst(this, true /* update */, false /* process_frames */); !fst.is_done(); fst.next()) {
1447 fst.current()->oops_do(f, cf, fst.register_map());
1448 }
1449 }
1450
1451 #ifdef ASSERT
1452 void JavaThread::verify_states_for_handshake() {
1453 // This checks that the thread has a correct frame state during a handshake.
1454 verify_frame_info();
1455 }
1456 #endif
1457
1458 void JavaThread::nmethods_do(NMethodClosure* cf) {
1459 DEBUG_ONLY(verify_frame_info();)
1460 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXWrite, Thread::current());)
1461
1462 if (has_last_Java_frame()) {
1463 // Traverse the execution stack
1464 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1465 fst.current()->nmethod_do(cf);
1466 }
1467 }
1468
1469 if (jvmti_thread_state() != nullptr) {
1470 jvmti_thread_state()->nmethods_do(cf);
1471 }
1472
1473 #if INCLUDE_JVMCI
1474 if (_live_nmethod != nullptr) {
1475 cf->do_nmethod(_live_nmethod);
1476 }
1477 #endif
1478 }
1479
1480 void JavaThread::metadata_do(MetadataClosure* f) {
1481 if (has_last_Java_frame()) {
1482 // Traverse the execution stack to call f() on the methods in the stack
1483 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1484 fst.current()->metadata_do(f);
1485 }
1486 } else if (is_Compiler_thread()) {
1487 // need to walk ciMetadata in current compile tasks to keep alive.
1488 CompilerThread* ct = (CompilerThread*)this;
1489 if (ct->env() != nullptr) {
1490 ct->env()->metadata_do(f);
1491 }
1492 CompileTask* task = ct->task();
1493 if (task != nullptr) {
1494 task->metadata_do(f);
1495 }
1496 }
1497 }
1498
1499 // Printing
1500 static const char* _get_thread_state_name(JavaThreadState _thread_state) {
1501 switch (_thread_state) {
1502 case _thread_uninitialized: return "_thread_uninitialized";
1503 case _thread_new: return "_thread_new";
1504 case _thread_new_trans: return "_thread_new_trans";
1505 case _thread_in_native: return "_thread_in_native";
1506 case _thread_in_native_trans: return "_thread_in_native_trans";
1507 case _thread_in_vm: return "_thread_in_vm";
1508 case _thread_in_vm_trans: return "_thread_in_vm_trans";
1509 case _thread_in_Java: return "_thread_in_Java";
1510 case _thread_in_Java_trans: return "_thread_in_Java_trans";
1511 case _thread_blocked: return "_thread_blocked";
1512 case _thread_blocked_trans: return "_thread_blocked_trans";
1513 default: return "unknown thread state";
1514 }
1515 }
1516
1517 void JavaThread::print_thread_state_on(outputStream *st) const {
1518 st->print_cr(" JavaThread state: %s", _get_thread_state_name(_thread_state));
1519 }
1520
1521 // Called by Threads::print() for VM_PrintThreads operation
1522 void JavaThread::print_on(outputStream *st, bool print_extended_info) const {
1523 st->print_raw("\"");
1524 st->print_raw(name());
1525 st->print_raw("\" ");
1526 oop thread_oop = threadObj();
1527 if (thread_oop != nullptr) {
1528 st->print("#" INT64_FORMAT " [%ld] ", (int64_t)java_lang_Thread::thread_id(thread_oop), (long) osthread()->thread_id());
1529 if (java_lang_Thread::is_daemon(thread_oop)) st->print("daemon ");
1530 st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
1531 }
1532 Thread::print_on(st, print_extended_info);
1533 // print guess for valid stack memory region (assume 4K pages); helps lock debugging
1534 st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
1535 if (thread_oop != nullptr) {
1536 if (is_vthread_mounted()) {
1537 oop vt = vthread();
1538 assert(vt != nullptr, "");
1539 st->print_cr(" Carrying virtual thread #" INT64_FORMAT, (int64_t)java_lang_Thread::thread_id(vt));
1540 } else {
1541 st->print_cr(" java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
1542 }
1543 }
1544 #ifndef PRODUCT
1545 _safepoint_state->print_on(st);
1546 #endif // PRODUCT
1547 if (is_Compiler_thread()) {
1548 CompileTask *task = ((CompilerThread*)this)->task();
1549 if (task != nullptr) {
1550 st->print(" Compiling: ");
1551 task->print(st, nullptr, true, false);
1552 } else {
1553 st->print(" No compile task");
1554 }
1555 st->cr();
1556 }
1557 }
1558
1559 void JavaThread::print() const { print_on(tty); }
1560
1561 void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
1562 st->print("%s", get_thread_name_string(buf, buflen));
1563 }
1564
1565 // Called by fatal error handler. The difference between this and
1566 // JavaThread::print() is that we can't grab lock or allocate memory.
1567 void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
1568 st->print("%s \"%s\"", type_name(), get_thread_name_string(buf, buflen));
1569 Thread* current = Thread::current_or_null_safe();
1570 assert(current != nullptr, "cannot be called by a detached thread");
1571 st->fill_to(60);
1572 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1573 // Only access threadObj() if current thread is not a JavaThread
1574 // or if it is a JavaThread that can safely access oops.
1575 oop thread_obj = threadObj();
1576 if (thread_obj != nullptr) {
1577 st->print(java_lang_Thread::is_daemon(thread_obj) ? " daemon" : " ");
1578 }
1579 }
1580 st->print(" [");
1581 st->print("%s", _get_thread_state_name(_thread_state));
1582 if (osthread()) {
1583 st->print(", id=%d", osthread()->thread_id());
1584 }
1585 // Use raw field members for stack base/size as this could be
1586 // called before a thread has run enough to initialize them.
1587 st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ") (" PROPERFMT ")",
1588 p2i(_stack_base - _stack_size), p2i(_stack_base),
1589 PROPERFMTARGS(_stack_size));
1590 st->print("]");
1591
1592 ThreadsSMRSupport::print_info_on(this, st);
1593 return;
1594 }
1595
1596
1597 // Verification
1598
1599 void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
1600 // ignore if there is no stack
1601 if (!has_last_Java_frame()) return;
1602 // traverse the stack frames. Starts from top frame.
1603 for (StackFrameStream fst(this, true /* update_map */, true /* process_frames */, false /* walk_cont */); !fst.is_done(); fst.next()) {
1604 frame* fr = fst.current();
1605 f(fr, fst.register_map());
1606 }
1607 }
1608
1609 static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
1610
1611 void JavaThread::verify() {
1612 // Verify oops in the thread.
1613 oops_do(&VerifyOopClosure::verify_oop, nullptr);
1614
1615 // Verify the stack frames.
1616 frames_do(frame_verify);
1617 }
1618
1619 // CR 6300358 (sub-CR 2137150)
1620 // Most callers of this method assume that it can't return null but a
1621 // thread may not have a name whilst it is in the process of attaching to
1622 // the VM - see CR 6412693, and there are places where a JavaThread can be
1623 // seen prior to having its threadObj set (e.g., JNI attaching threads and
1624 // if vm exit occurs during initialization). These cases can all be accounted
1625 // for such that this method never returns null.
1626 const char* JavaThread::name() const {
1627 if (Thread::is_JavaThread_protected(/* target */ this)) {
1628 // The target JavaThread is protected so get_thread_name_string() is safe:
1629 return get_thread_name_string();
1630 }
1631
1632 // The target JavaThread is not protected so we return the default:
1633 return Thread::name();
1634 }
1635
1636 // Like name() but doesn't include the protection check. This must only be
1637 // called when it is known to be safe, even though the protection check can't tell
1638 // that e.g. when this thread is the init_thread() - see instanceKlass.cpp.
1639 const char* JavaThread::name_raw() const {
1640 return get_thread_name_string();
1641 }
1642
1643 // Returns a non-null representation of this thread's name, or a suitable
1644 // descriptive string if there is no set name.
1645 const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
1646 const char* name_str;
1647 #ifdef ASSERT
1648 Thread* current = Thread::current_or_null_safe();
1649 assert(current != nullptr, "cannot be called by a detached thread");
1650 if (!current->is_Java_thread() || JavaThread::cast(current)->is_oop_safe()) {
1651 // Only access threadObj() if current thread is not a JavaThread
1652 // or if it is a JavaThread that can safely access oops.
1653 #endif
1654 oop thread_obj = threadObj();
1655 if (thread_obj != nullptr) {
1656 oop name = java_lang_Thread::name(thread_obj);
1657 if (name != nullptr) {
1658 if (buf == nullptr) {
1659 name_str = java_lang_String::as_utf8_string(name);
1660 } else {
1661 name_str = java_lang_String::as_utf8_string(name, buf, buflen);
1662 }
1663 } else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
1664 name_str = "<no-name - thread is attaching>";
1665 } else {
1666 name_str = "<un-named>";
1667 }
1668 } else {
1669 name_str = Thread::name();
1670 }
1671 #ifdef ASSERT
1672 } else {
1673 // Current JavaThread has exited...
1674 if (current == this) {
1675 // ... and is asking about itself:
1676 name_str = "<no-name - current JavaThread has exited>";
1677 } else {
1678 // ... and it can't safely determine this JavaThread's name so
1679 // use the default thread name.
1680 name_str = Thread::name();
1681 }
1682 }
1683 #endif
1684 assert(name_str != nullptr, "unexpected null thread name");
1685 return name_str;
1686 }
1687
1688 // Helper to extract the name from the thread oop for logging.
1689 const char* JavaThread::name_for(oop thread_obj) {
1690 assert(thread_obj != nullptr, "precondition");
1691 oop name = java_lang_Thread::name(thread_obj);
1692 const char* name_str;
1693 if (name != nullptr) {
1694 name_str = java_lang_String::as_utf8_string(name);
1695 } else {
1696 name_str = "<un-named>";
1697 }
1698 return name_str;
1699 }
1700
1701 void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
1702
1703 assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
1704 assert(NoPriority <= prio && prio <= MaxPriority, "sanity check");
1705 // Link Java Thread object <-> C++ Thread
1706
1707 // Get the C++ thread object (an oop) from the JNI handle (a jthread)
1708 // and put it into a new Handle. The Handle "thread_oop" can then
1709 // be used to pass the C++ thread object to other methods.
1710
1711 // Set the Java level thread object (jthread) field of the
1712 // new thread (a JavaThread *) to C++ thread object using the
1713 // "thread_oop" handle.
1714
1715 // Set the thread field (a JavaThread *) of the
1716 // oop representing the java_lang_Thread to the new thread (a JavaThread *).
1717
1718 Handle thread_oop(Thread::current(),
1719 JNIHandles::resolve_non_null(jni_thread));
1720 assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
1721 "must be initialized");
1722 set_threadOopHandles(thread_oop());
1723
1724 if (prio == NoPriority) {
1725 prio = java_lang_Thread::priority(thread_oop());
1726 assert(prio != NoPriority, "A valid priority should be present");
1727 }
1728
1729 // Push the Java priority down to the native thread; needs Threads_lock
1730 Thread::set_priority(this, prio);
1731
1732 // Add the new thread to the Threads list and set it in motion.
1733 // We must have threads lock in order to call Threads::add.
1734 // It is crucial that we do not block before the thread is
1735 // added to the Threads list for if a GC happens, then the java_thread oop
1736 // will not be visited by GC.
1737 Threads::add(this);
1738 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
1739 // on a ThreadsList. We don't want to wait for the release when the
1740 // Theads_lock is dropped somewhere in the caller since the JavaThread*
1741 // is already visible to JVM/TI via the ThreadsList.
1742 java_lang_Thread::release_set_thread(thread_oop(), this);
1743 }
1744
1745 oop JavaThread::current_park_blocker() {
1746 // Support for JSR-166 locks
1747 oop thread_oop = threadObj();
1748 if (thread_oop != nullptr) {
1749 return java_lang_Thread::park_blocker(thread_oop);
1750 }
1751 return nullptr;
1752 }
1753
1754 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1755 // This is the external format, selecting the platform or vthread
1756 // as applicable, and allowing for a native-only stack.
1757 void JavaThread::print_jni_stack() {
1758 assert(this == JavaThread::current(), "Can't print stack of other threads");
1759 if (!has_last_Java_frame()) {
1760 print_native_stack_on(tty);
1761 } else {
1762 print_active_stack_on(tty);
1763 }
1764 }
1765
1766 void JavaThread::print_native_stack_on(outputStream *st) {
1767 assert(this == JavaThread::current(), "Can't print stack of other threads");
1768 ResourceMark rm;
1769 char* buf = NEW_RESOURCE_ARRAY_RETURN_NULL(char, O_BUFLEN);
1770 if (buf == nullptr) {
1771 st->print_cr("Unable to print native stack - out of memory");
1772 return;
1773 }
1774 address lastpc = nullptr;
1775 if (os::platform_print_native_stack(st, nullptr, buf, O_BUFLEN, lastpc)) {
1776 // We have printed the native stack in platform-specific code,
1777 // so nothing else to do in this case.
1778 } else {
1779 frame f = os::current_frame();
1780 VMError::print_native_stack(st, f, this, true /*print_source_info */,
1781 -1 /* max stack */, buf, O_BUFLEN);
1782 }
1783 }
1784
1785 void JavaThread::print_stack_on(outputStream* st) {
1786 if (!has_last_Java_frame()) return;
1787
1788 Thread* current_thread = Thread::current();
1789 ResourceMark rm(current_thread);
1790 HandleMark hm(current_thread);
1791
1792 RegisterMap reg_map(this,
1793 RegisterMap::UpdateMap::include,
1794 RegisterMap::ProcessFrames::include,
1795 RegisterMap::WalkContinuation::skip);
1796 vframe* start_vf = platform_thread_last_java_vframe(®_map);
1797 int count = 0;
1798 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1799 if (f->is_java_frame()) {
1800 javaVFrame* jvf = javaVFrame::cast(f);
1801 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1802
1803 // Print out lock information
1804 if (JavaMonitorsInStackTrace) {
1805 jvf->print_lock_info_on(st, count);
1806 }
1807 } else {
1808 // Ignore non-Java frames
1809 }
1810
1811 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1812 count++;
1813 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1814 }
1815 }
1816
1817 void JavaThread::print_vthread_stack_on(outputStream* st) {
1818 assert(is_vthread_mounted(), "Caller should have checked this");
1819 assert(has_last_Java_frame(), "must be");
1820
1821 Thread* current_thread = Thread::current();
1822 ResourceMark rm(current_thread);
1823 HandleMark hm(current_thread);
1824
1825 RegisterMap reg_map(this,
1826 RegisterMap::UpdateMap::include,
1827 RegisterMap::ProcessFrames::include,
1828 RegisterMap::WalkContinuation::include);
1829 ContinuationEntry* cont_entry = last_continuation();
1830 vframe* start_vf = last_java_vframe(®_map);
1831 int count = 0;
1832 for (vframe* f = start_vf; f != nullptr; f = f->sender()) {
1833 // Watch for end of vthread stack
1834 if (Continuation::is_continuation_enterSpecial(f->fr())) {
1835 assert(cont_entry == Continuation::get_continuation_entry_for_entry_frame(this, f->fr()), "");
1836 if (cont_entry->is_virtual_thread()) {
1837 break;
1838 }
1839 cont_entry = cont_entry->parent();
1840 }
1841 if (f->is_java_frame()) {
1842 javaVFrame* jvf = javaVFrame::cast(f);
1843 java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
1844
1845 // Print out lock information
1846 if (JavaMonitorsInStackTrace) {
1847 jvf->print_lock_info_on(st, count);
1848 }
1849 } else {
1850 // Ignore non-Java frames
1851 }
1852
1853 // Bail-out case for too deep stacks if MaxJavaStackTraceDepth > 0
1854 count++;
1855 if (MaxJavaStackTraceDepth > 0 && MaxJavaStackTraceDepth == count) return;
1856 }
1857 }
1858
1859 void JavaThread::print_active_stack_on(outputStream* st) {
1860 if (is_vthread_mounted()) {
1861 print_vthread_stack_on(st);
1862 } else {
1863 print_stack_on(st);
1864 }
1865 }
1866
1867 #if INCLUDE_JVMTI
1868 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1869 JvmtiThreadState* JavaThread::rebind_to_jvmti_thread_state_of(oop thread_oop) {
1870 set_jvmti_vthread(thread_oop);
1871
1872 // unbind current JvmtiThreadState from JavaThread
1873 JvmtiThreadState::unbind_from(jvmti_thread_state(), this);
1874
1875 // bind new JvmtiThreadState to JavaThread
1876 JvmtiThreadState::bind_to(java_lang_Thread::jvmti_thread_state(thread_oop), this);
1877
1878 // enable interp_only_mode for virtual or carrier thread if it has pending bit
1879 JvmtiThreadState::process_pending_interp_only(this);
1880
1881 return jvmti_thread_state();
1882 }
1883 #endif
1884
1885 // JVMTI PopFrame support
1886 void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
1887 assert(_popframe_preserved_args == nullptr, "should not wipe out old PopFrame preserved arguments");
1888 if (in_bytes(size_in_bytes) != 0) {
1889 _popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
1890 _popframe_preserved_args_size = in_bytes(size_in_bytes);
1891 Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
1892 }
1893 }
1894
1895 void* JavaThread::popframe_preserved_args() {
1896 return _popframe_preserved_args;
1897 }
1898
1899 ByteSize JavaThread::popframe_preserved_args_size() {
1900 return in_ByteSize(_popframe_preserved_args_size);
1901 }
1902
1903 WordSize JavaThread::popframe_preserved_args_size_in_words() {
1904 int sz = in_bytes(popframe_preserved_args_size());
1905 assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
1906 return in_WordSize(sz / wordSize);
1907 }
1908
1909 void JavaThread::popframe_free_preserved_args() {
1910 assert(_popframe_preserved_args != nullptr, "should not free PopFrame preserved arguments twice");
1911 FREE_C_HEAP_ARRAY(char, (char*)_popframe_preserved_args);
1912 _popframe_preserved_args = nullptr;
1913 _popframe_preserved_args_size = 0;
1914 }
1915
1916 #ifndef PRODUCT
1917
1918 void JavaThread::trace_frames() {
1919 tty->print_cr("[Describe stack]");
1920 int frame_no = 1;
1921 for (StackFrameStream fst(this, true /* update */, true /* process_frames */); !fst.is_done(); fst.next()) {
1922 tty->print(" %d. ", frame_no++);
1923 fst.current()->print_value_on(tty);
1924 tty->cr();
1925 }
1926 }
1927
1928 class PrintAndVerifyOopClosure: public OopClosure {
1929 protected:
1930 template <class T> inline void do_oop_work(T* p) {
1931 oop obj = RawAccess<>::oop_load(p);
1932 if (obj == nullptr) return;
1933 tty->print(INTPTR_FORMAT ": ", p2i(p));
1934 if (oopDesc::is_oop_or_null(obj)) {
1935 if (obj->is_objArray()) {
1936 tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
1937 } else {
1938 obj->print();
1939 }
1940 } else {
1941 tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
1942 }
1943 tty->cr();
1944 }
1945 public:
1946 virtual void do_oop(oop* p) { do_oop_work(p); }
1947 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1948 };
1949
1950 #ifdef ASSERT
1951 // Print or validate the layout of stack frames
1952 void JavaThread::print_frame_layout(int depth, bool validate_only) {
1953 ResourceMark rm;
1954 PreserveExceptionMark pm(this);
1955 FrameValues values;
1956 int frame_no = 0;
1957 for (StackFrameStream fst(this, true, true, true); !fst.is_done(); fst.next()) {
1958 fst.current()->describe(values, ++frame_no, fst.register_map());
1959 if (depth == frame_no) break;
1960 }
1961 Continuation::describe(values);
1962 if (validate_only) {
1963 values.validate();
1964 } else {
1965 tty->print_cr("[Describe stack layout]");
1966 values.print(this);
1967 }
1968 }
1969 #endif
1970
1971 void JavaThread::trace_stack_from(vframe* start_vf) {
1972 ResourceMark rm;
1973 int vframe_no = 1;
1974 for (vframe* f = start_vf; f; f = f->sender()) {
1975 if (f->is_java_frame()) {
1976 javaVFrame::cast(f)->print_activation(vframe_no++);
1977 } else {
1978 f->print();
1979 }
1980 if (vframe_no > StackPrintLimit) {
1981 tty->print_cr("...<more frames>...");
1982 return;
1983 }
1984 }
1985 }
1986
1987
1988 void JavaThread::trace_stack() {
1989 if (!has_last_Java_frame()) return;
1990 Thread* current_thread = Thread::current();
1991 ResourceMark rm(current_thread);
1992 HandleMark hm(current_thread);
1993 RegisterMap reg_map(this,
1994 RegisterMap::UpdateMap::include,
1995 RegisterMap::ProcessFrames::include,
1996 RegisterMap::WalkContinuation::skip);
1997 trace_stack_from(last_java_vframe(®_map));
1998 }
1999
2000
2001 #endif // PRODUCT
2002
2003 // Slow-path increment of the held monitor counts. JNI locking is always
2004 // this slow-path.
2005 void JavaThread::inc_held_monitor_count(intx i, bool jni) {
2006 #ifdef SUPPORT_MONITOR_COUNT
2007 assert(_held_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _held_monitor_count);
2008 _held_monitor_count += i;
2009 if (jni) {
2010 assert(_jni_monitor_count >= 0, "Must always be non-negative: " INTX_FORMAT, _jni_monitor_count);
2011 _jni_monitor_count += i;
2012 }
2013 assert(_held_monitor_count >= _jni_monitor_count, "Monitor count discrepancy detected - held count "
2014 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2015 #endif
2016 }
2017
2018 // Slow-path decrement of the held monitor counts. JNI unlocking is always
2019 // this slow-path.
2020 void JavaThread::dec_held_monitor_count(intx i, bool jni) {
2021 #ifdef SUPPORT_MONITOR_COUNT
2022 _held_monitor_count -= i;
2023 assert(_held_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _held_monitor_count);
2024 if (jni) {
2025 _jni_monitor_count -= i;
2026 assert(_jni_monitor_count >= 0, "Must always be greater than 0: " INTX_FORMAT, _jni_monitor_count);
2027 }
2028 // When a thread is detaching with still owned JNI monitors, the logic that releases
2029 // the monitors doesn't know to set the "jni" flag and so the counts can get out of sync.
2030 // So we skip this assert if the thread is exiting. Once all monitors are unlocked the
2031 // JNI count is directly set to zero.
2032 assert(_held_monitor_count >= _jni_monitor_count || is_exiting(), "Monitor count discrepancy detected - held count "
2033 INTX_FORMAT " is less than JNI count " INTX_FORMAT, _held_monitor_count, _jni_monitor_count);
2034 #endif
2035 }
2036
2037 frame JavaThread::vthread_last_frame() {
2038 assert (is_vthread_mounted(), "Virtual thread not mounted");
2039 return last_frame();
2040 }
2041
2042 frame JavaThread::carrier_last_frame(RegisterMap* reg_map) {
2043 const ContinuationEntry* entry = vthread_continuation();
2044 guarantee (entry != nullptr, "Not a carrier thread");
2045 frame f = entry->to_frame();
2046 if (reg_map->process_frames()) {
2047 entry->flush_stack_processing(this);
2048 }
2049 entry->update_register_map(reg_map);
2050 return f.sender(reg_map);
2051 }
2052
2053 frame JavaThread::platform_thread_last_frame(RegisterMap* reg_map) {
2054 return is_vthread_mounted() ? carrier_last_frame(reg_map) : last_frame();
2055 }
2056
2057 javaVFrame* JavaThread::last_java_vframe(const frame f, RegisterMap *reg_map) {
2058 assert(reg_map != nullptr, "a map must be given");
2059 for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
2060 if (vf->is_java_frame()) return javaVFrame::cast(vf);
2061 }
2062 return nullptr;
2063 }
2064
2065 Klass* JavaThread::security_get_caller_class(int depth) {
2066 ResetNoHandleMark rnhm;
2067 HandleMark hm(Thread::current());
2068
2069 vframeStream vfst(this);
2070 vfst.security_get_caller_frame(depth);
2071 if (!vfst.at_end()) {
2072 return vfst.method()->method_holder();
2073 }
2074 return nullptr;
2075 }
2076
2077 // Internal convenience function for millisecond resolution sleeps.
2078 bool JavaThread::sleep(jlong millis) {
2079 jlong nanos;
2080 if (millis > max_jlong / NANOUNITS_PER_MILLIUNIT) {
2081 // Conversion to nanos would overflow, saturate at max
2082 nanos = max_jlong;
2083 } else {
2084 nanos = millis * NANOUNITS_PER_MILLIUNIT;
2085 }
2086 return sleep_nanos(nanos);
2087 }
2088
2089 // java.lang.Thread.sleep support
2090 // Returns true if sleep time elapsed as expected, and false
2091 // if the thread was interrupted.
2092 bool JavaThread::sleep_nanos(jlong nanos) {
2093 assert(this == Thread::current(), "thread consistency check");
2094 assert(nanos >= 0, "nanos are in range");
2095
2096 ParkEvent * const slp = this->_SleepEvent;
2097 // Because there can be races with thread interruption sending an unpark()
2098 // to the event, we explicitly reset it here to avoid an immediate return.
2099 // The actual interrupt state will be checked before we park().
2100 slp->reset();
2101 // Thread interruption establishes a happens-before ordering in the
2102 // Java Memory Model, so we need to ensure we synchronize with the
2103 // interrupt state.
2104 OrderAccess::fence();
2105
2106 jlong prevtime = os::javaTimeNanos();
2107
2108 jlong nanos_remaining = nanos;
2109
2110 for (;;) {
2111 // interruption has precedence over timing out
2112 if (this->is_interrupted(true)) {
2113 return false;
2114 }
2115
2116 if (nanos_remaining <= 0) {
2117 return true;
2118 }
2119
2120 {
2121 ThreadBlockInVM tbivm(this);
2122 OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
2123 slp->park_nanos(nanos_remaining);
2124 }
2125
2126 // Update elapsed time tracking
2127 jlong newtime = os::javaTimeNanos();
2128 if (newtime - prevtime < 0) {
2129 // time moving backwards, should only happen if no monotonic clock
2130 // not a guarantee() because JVM should not abort on kernel/glibc bugs
2131 assert(false,
2132 "unexpected time moving backwards detected in JavaThread::sleep()");
2133 } else {
2134 nanos_remaining -= (newtime - prevtime);
2135 }
2136 prevtime = newtime;
2137 }
2138 }
2139
2140 // Last thread running calls java.lang.Shutdown.shutdown()
2141 void JavaThread::invoke_shutdown_hooks() {
2142 HandleMark hm(this);
2143
2144 // We could get here with a pending exception, if so clear it now.
2145 if (this->has_pending_exception()) {
2146 this->clear_pending_exception();
2147 }
2148
2149 EXCEPTION_MARK;
2150 Klass* shutdown_klass =
2151 SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
2152 THREAD);
2153 if (shutdown_klass != nullptr) {
2154 // SystemDictionary::resolve_or_null will return null if there was
2155 // an exception. If we cannot load the Shutdown class, just don't
2156 // call Shutdown.shutdown() at all. This will mean the shutdown hooks
2157 // won't be run. Note that if a shutdown hook was registered,
2158 // the Shutdown class would have already been loaded
2159 // (Runtime.addShutdownHook will load it).
2160 JavaValue result(T_VOID);
2161 JavaCalls::call_static(&result,
2162 shutdown_klass,
2163 vmSymbols::shutdown_name(),
2164 vmSymbols::void_method_signature(),
2165 THREAD);
2166 }
2167 CLEAR_PENDING_EXCEPTION;
2168 }
2169
2170 #ifndef PRODUCT
2171 void JavaThread::verify_cross_modify_fence_failure(JavaThread *thread) {
2172 report_vm_error(__FILE__, __LINE__, "Cross modify fence failure", "%p", thread);
2173 }
2174 #endif
2175
2176 // Helper function to create the java.lang.Thread object for a
2177 // VM-internal thread. The thread will have the given name, and be
2178 // a member of the "system" ThreadGroup.
2179 Handle JavaThread::create_system_thread_object(const char* name, TRAPS) {
2180 Handle string = java_lang_String::create_from_str(name, CHECK_NH);
2181
2182 // Initialize thread_oop to put it into the system threadGroup.
2183 // This is done by calling the Thread(ThreadGroup group, String name) constructor.
2184 Handle thread_group(THREAD, Universe::system_thread_group());
2185 Handle thread_oop =
2186 JavaCalls::construct_new_instance(vmClasses::Thread_klass(),
2187 vmSymbols::threadgroup_string_void_signature(),
2188 thread_group,
2189 string,
2190 CHECK_NH);
2191
2192 return thread_oop;
2193 }
2194
2195 // Starts the target JavaThread as a daemon of the given priority, and
2196 // bound to the given java.lang.Thread instance.
2197 // The Threads_lock is held for the duration.
2198 void JavaThread::start_internal_daemon(JavaThread* current, JavaThread* target,
2199 Handle thread_oop, ThreadPriority prio) {
2200
2201 assert(target->osthread() != nullptr, "target thread is not properly initialized");
2202
2203 MutexLocker mu(current, Threads_lock);
2204
2205 // Initialize the fields of the thread_oop first.
2206 if (prio != NoPriority) {
2207 java_lang_Thread::set_priority(thread_oop(), prio);
2208 // Note: we don't call os::set_priority here. Possibly we should,
2209 // else all threads should call it themselves when they first run.
2210 }
2211
2212 java_lang_Thread::set_daemon(thread_oop());
2213
2214 // Now bind the thread_oop to the target JavaThread.
2215 target->set_threadOopHandles(thread_oop());
2216
2217 Threads::add(target); // target is now visible for safepoint/handshake
2218 // Publish the JavaThread* in java.lang.Thread after the JavaThread* is
2219 // on a ThreadsList. We don't want to wait for the release when the
2220 // Theads_lock is dropped when the 'mu' destructor is run since the
2221 // JavaThread* is already visible to JVM/TI via the ThreadsList.
2222
2223 assert(java_lang_Thread::thread(thread_oop()) == nullptr, "must not be alive");
2224 java_lang_Thread::release_set_thread(thread_oop(), target); // isAlive == true now
2225 Thread::start(target);
2226 }
2227
2228 void JavaThread::vm_exit_on_osthread_failure(JavaThread* thread) {
2229 // At this point it may be possible that no osthread was created for the
2230 // JavaThread due to lack of resources. However, since this must work
2231 // for critical system threads just check and abort if this fails.
2232 if (thread->osthread() == nullptr) {
2233 // This isn't really an OOM condition, but historically this is what
2234 // we report.
2235 vm_exit_during_initialization("java.lang.OutOfMemoryError",
2236 os::native_thread_creation_failed_msg());
2237 }
2238 }
2239
2240 void JavaThread::pretouch_stack() {
2241 // Given an established java thread stack with usable area followed by
2242 // shadow zone and reserved/yellow/red zone, pretouch the usable area ranging
2243 // from the current frame down to the start of the shadow zone.
2244 const address end = _stack_overflow_state.shadow_zone_safe_limit();
2245 if (is_in_full_stack(end)) {
2246 char* p1 = (char*) alloca(1);
2247 address here = (address) &p1;
2248 if (is_in_full_stack(here) && here > end) {
2249 size_t to_alloc = here - end;
2250 char* p2 = (char*) alloca(to_alloc);
2251 log_trace(os, thread)("Pretouching thread stack for " UINTX_FORMAT ": " RANGEFMT ".",
2252 (uintx) osthread()->thread_id(), RANGEFMTARGS(p2, to_alloc));
2253 os::pretouch_memory(p2, p2 + to_alloc,
2254 NOT_AIX(os::vm_page_size()) AIX_ONLY(4096));
2255 }
2256 }
2257 }
2258
2259 // Deferred OopHandle release support.
2260
2261 class OopHandleList : public CHeapObj<mtInternal> {
2262 static const int _count = 4;
2263 OopHandle _handles[_count];
2264 OopHandleList* _next;
2265 int _index;
2266 public:
2267 OopHandleList(OopHandleList* next) : _next(next), _index(0) {}
2268 void add(OopHandle h) {
2269 assert(_index < _count, "too many additions");
2270 _handles[_index++] = h;
2271 }
2272 ~OopHandleList() {
2273 assert(_index == _count, "usage error");
2274 for (int i = 0; i < _index; i++) {
2275 _handles[i].release(JavaThread::thread_oop_storage());
2276 }
2277 }
2278 OopHandleList* next() const { return _next; }
2279 };
2280
2281 OopHandleList* JavaThread::_oop_handle_list = nullptr;
2282
2283 // Called by the ServiceThread to do the work of releasing
2284 // the OopHandles.
2285 void JavaThread::release_oop_handles() {
2286 OopHandleList* list;
2287 {
2288 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2289 list = _oop_handle_list;
2290 _oop_handle_list = nullptr;
2291 }
2292 assert(!SafepointSynchronize::is_at_safepoint(), "cannot be called at a safepoint");
2293
2294 while (list != nullptr) {
2295 OopHandleList* l = list;
2296 list = l->next();
2297 delete l;
2298 }
2299 }
2300
2301 // Add our OopHandles for later release.
2302 void JavaThread::add_oop_handles_for_release() {
2303 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
2304 OopHandleList* new_head = new OopHandleList(_oop_handle_list);
2305 new_head->add(_threadObj);
2306 new_head->add(_vthread);
2307 new_head->add(_jvmti_vthread);
2308 new_head->add(_scopedValueCache);
2309 _oop_handle_list = new_head;
2310 Service_lock->notify_all();
2311 }