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