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