1 /*
2 * Copyright (c) 1997, 2026, 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 #ifndef SHARE_RUNTIME_JAVATHREAD_HPP
27 #define SHARE_RUNTIME_JAVATHREAD_HPP
28
29 #include "jni.h"
30 #include "memory/allocation.hpp"
31 #include "oops/oop.hpp"
32 #include "oops/oopHandle.hpp"
33 #include "runtime/continuationEntry.hpp"
34 #include "runtime/frame.hpp"
35 #include "runtime/globals.hpp"
36 #include "runtime/handshake.hpp"
37 #include "runtime/javaFrameAnchor.hpp"
38 #include "runtime/lockStack.hpp"
39 #include "runtime/park.hpp"
40 #include "runtime/safepointMechanism.hpp"
41 #include "runtime/stackOverflow.hpp"
42 #include "runtime/stackWatermarkSet.hpp"
43 #include "runtime/suspendResumeManager.hpp"
44 #include "runtime/thread.hpp"
45 #include "runtime/threadHeapSampler.hpp"
46 #include "runtime/threadIdentifier.hpp"
47 #include "runtime/threadStatisticalInfo.hpp"
48 #include "utilities/exceptions.hpp"
49 #include "utilities/globalDefinitions.hpp"
50 #include "utilities/macros.hpp"
51 #if INCLUDE_JFR
52 #include "jfr/support/jfrThreadExtension.hpp"
53 #include "utilities/ticks.hpp"
54 #endif
55
56 class AsyncExceptionHandshakeClosure;
57 class DeoptResourceMark;
58 class InternalOOMEMark;
59 class JNIHandleBlock;
60 class JVMCIRuntime;
61
62 class JvmtiDeferredUpdates;
63 class JvmtiSampledObjectAllocEventCollector;
64 class JvmtiThreadState;
65
66 class Metadata;
67 class ObjectMonitor;
68 class OopHandleList;
69 class OopStorage;
70 class OSThread;
71
72 class ThreadsList;
73 class ThreadSafepointState;
74 class ThreadStatistics;
75
76 class vframeArray;
77 class vframe;
78 class javaVFrame;
79
80 class JavaThread;
81 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
82
83 class EventVirtualThreadPinned;
84 class ThreadWXEnable;
85
86 class JavaThread: public Thread {
87 friend class VMStructs;
88 friend class JVMCIVMStructs;
89 friend class WhiteBox;
90 friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
91 friend class HandshakeState;
92 friend class Continuation;
93 friend class Threads;
94 friend class ServiceThread; // for deferred OopHandle release access
95 private:
96 bool _on_thread_list; // Is set when this JavaThread is added to the Threads list
97
98 // All references to Java objects managed via OopHandles. These
99 // have to be released by the ServiceThread after the JavaThread has
100 // terminated - see add_oop_handles_for_release().
101 OopHandle _threadObj; // The Java level thread object
102 OopHandle _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
103 OopHandle _jvmti_vthread;
104 OopHandle _scopedValueCache;
105
106 static OopStorage* _thread_oop_storage;
107
108 #ifdef ASSERT
109 private:
110 int _java_call_counter;
111
112 public:
113 int java_call_counter() { return _java_call_counter; }
114 void inc_java_call_counter() { _java_call_counter++; }
115 void dec_java_call_counter() {
116 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
117 _java_call_counter--;
118 }
119 private: // restore original namespace restriction
120 #endif // ifdef ASSERT
121
122 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state
123
124 ThreadFunction _entry_point;
125
126 JNIEnv _jni_environment;
127
128 // Deopt support
129 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization
130
131 nmethod* _deopt_nmethod; // nmethod that is currently being deoptimized
132 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays
133 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped
134 // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
135 // will be carried out as soon as possible which, in most cases, is just before deoptimization of
136 // the frame, when control returns to it.
137 JvmtiDeferredUpdates* _jvmti_deferred_updates;
138
139 // Handshake value for fixing 6243940. We need a place for the i2c
140 // adapter to store the callee Method*. This value is NEVER live
141 // across a gc point so it does NOT have to be gc'd
142 // The handshake is open ended since we can't be certain that it will
143 // be nulled. This is because we rarely ever see the race and end up
144 // in handle_wrong_method which is the backend of the handshake. See
145 // code in i2c adapters and handle_wrong_method.
146
147 Method* _callee_target;
148
149 // Used to pass back results to the interpreter or generated code running Java code.
150 oop _vm_result_oop; // oop result is GC-preserved
151 Metadata* _vm_result_metadata; // non-oop result
152
153 ObjectMonitor* volatile _current_pending_monitor; // ObjectMonitor this thread is waiting to lock
154 bool _current_pending_monitor_is_from_java; // locking is from Java code
155 ObjectMonitor* volatile _current_waiting_monitor; // ObjectMonitor on which this thread called Object.wait()
156
157 // Active_handles points to a block of handles
158 JNIHandleBlock* _active_handles;
159
160 // One-element thread local free list
161 JNIHandleBlock* _free_handle_block;
162
163 // ID used as owner for inflated monitors. Same as the j.l.Thread.tid of the
164 // current _vthread object, except during creation of the primordial and JNI
165 // attached thread cases where this field can have a temporary value.
166 int64_t _monitor_owner_id;
167
168 public:
169 void set_monitor_owner_id(int64_t id) {
170 ThreadIdentifier::verify_id(id);
171 _monitor_owner_id = id;
172 }
173 int64_t monitor_owner_id() const {
174 int64_t id = _monitor_owner_id;
175 ThreadIdentifier::verify_id(id);
176 return id;
177 }
178
179 // For tracking the heavyweight monitor the thread is pending on.
180 ObjectMonitor* current_pending_monitor() {
181 // Use AtomicAccess::load() to prevent data race between concurrent modification and
182 // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
183 // Especially, reloading pointer from thread after null check must be prevented.
184 return AtomicAccess::load(&_current_pending_monitor);
185 }
186 void set_current_pending_monitor(ObjectMonitor* monitor) {
187 AtomicAccess::store(&_current_pending_monitor, monitor);
188 }
189 void set_current_pending_monitor_is_from_java(bool from_java) {
190 _current_pending_monitor_is_from_java = from_java;
191 }
192 bool current_pending_monitor_is_from_java() {
193 return _current_pending_monitor_is_from_java;
194 }
195 ObjectMonitor* current_waiting_monitor() {
196 // See the comment in current_pending_monitor() above.
197 return AtomicAccess::load(&_current_waiting_monitor);
198 }
199 void set_current_waiting_monitor(ObjectMonitor* monitor) {
200 AtomicAccess::store(&_current_waiting_monitor, monitor);
201 }
202
203 // JNI handle support
204 JNIHandleBlock* active_handles() const { return _active_handles; }
205 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
206 JNIHandleBlock* free_handle_block() const { return _free_handle_block; }
207 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
208
209 void push_jni_handle_block();
210 void pop_jni_handle_block();
211
212 private:
213 enum SuspendFlags {
214 // NOTE: avoid using the sign-bit as cc generates different test code
215 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077
216 _obj_deopt = 0x00000008U // suspend for object reallocation and relocking for JVMTI agent
217 };
218
219 // various suspension related flags - atomically updated
220 volatile uint32_t _suspend_flags;
221
222 inline void set_suspend_flag(SuspendFlags f);
223 inline void clear_suspend_flag(SuspendFlags f);
224
225 public:
226 inline void set_obj_deopt_flag();
227 inline void clear_obj_deopt_flag();
228 bool is_obj_deopt_suspend() { return (_suspend_flags & _obj_deopt) != 0; }
229
230 // Asynchronous exception support
231 private:
232 friend class InstallAsyncExceptionHandshakeClosure;
233 friend class AsyncExceptionHandshakeClosure;
234 friend class HandshakeState;
235
236 void handle_async_exception(oop java_throwable);
237 public:
238 void install_async_exception(AsyncExceptionHandshakeClosure* aec = nullptr);
239 bool has_async_exception_condition();
240 inline void set_pending_unsafe_access_error();
241 static void send_async_exception(JavaThread* jt, oop java_throwable);
242
243 class NoAsyncExceptionDeliveryMark : public StackObj {
244 friend JavaThread;
245 JavaThread *_target;
246 inline NoAsyncExceptionDeliveryMark(JavaThread *t);
247 inline ~NoAsyncExceptionDeliveryMark();
248 };
249
250 // Safepoint support
251 public: // Expose _thread_state for SafeFetchInt()
252 volatile JavaThreadState _thread_state;
253 ThreadSafepointState* _safepoint_state; // Holds information about a thread during a safepoint
254 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened
255 NOT_PRODUCT(bool _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
256 #ifdef ASSERT
257 // Debug support for checking if code allows safepoints or not.
258 // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
259 // mutex, or blocking on an object synchronizer (Java locking).
260 // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
261 // the above cases. The class NoSafepointVerifier is used to set this counter.
262 int _no_safepoint_count; // If 0, thread allow a safepoint to happen
263
264 public:
265 void inc_no_safepoint_count() { _no_safepoint_count++; }
266 void dec_no_safepoint_count() { _no_safepoint_count--; }
267 bool is_in_no_safepoint_scope() { return _no_safepoint_count > 0; }
268 #endif // ASSERT
269 public:
270 // These functions check conditions before possibly going to a safepoint.
271 // including NoSafepointVerifier.
272 void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
273 void check_possible_safepoint() NOT_DEBUG_RETURN;
274
275 #ifdef ASSERT
276 private:
277 volatile uint64_t _visited_for_critical_count;
278
279 public:
280 void set_visited_for_critical_count(uint64_t safepoint_id) {
281 assert(_visited_for_critical_count == 0, "Must be reset before set");
282 assert((safepoint_id & 0x1) == 1, "Must be odd");
283 _visited_for_critical_count = safepoint_id;
284 }
285 void reset_visited_for_critical_count(uint64_t safepoint_id) {
286 assert(_visited_for_critical_count == safepoint_id, "Was not visited");
287 _visited_for_critical_count = 0;
288 }
289 bool was_visited_for_critical_count(uint64_t safepoint_id) const {
290 return _visited_for_critical_count == safepoint_id;
291 }
292 #endif // ASSERT
293
294 // JavaThread termination support
295 public:
296 enum TerminatedTypes {
297 _not_terminated = 0xDEAD - 3,
298 _thread_exiting, // JavaThread::exit() has been called for this thread
299 _thread_gc_barrier_detached, // thread's GC barrier has been detached
300 _thread_terminated, // JavaThread is removed from thread list
301 _vm_exited // JavaThread is still executing native code, but VM is terminated
302 // only VM_Exit can set _vm_exited
303 };
304
305 private:
306 // In general a JavaThread's _terminated field transitions as follows:
307 //
308 // _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
309 //
310 // _vm_exited is a special value to cover the case of a JavaThread
311 // executing native code after the VM itself is terminated.
312 //
313 // A JavaThread that fails to JNI attach has these _terminated field transitions:
314 // _not_terminated => _thread_terminated
315 //
316 volatile TerminatedTypes _terminated;
317
318 jint _in_deopt_handler; // count of deoptimization
319 // handlers thread is in
320 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access
321 volatile bool _throwing_unsafe_access_error; // Thread has faulted and is throwing an exception
322 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
323 // never locked) when throwing an exception. Used by interpreter only.
324 #if INCLUDE_JVMTI
325 volatile bool _carrier_thread_suspended; // Carrier thread is externally suspended
326 bool _is_disable_suspend; // JVMTI suspend is temporarily disabled; used on current thread only
327 bool _is_in_java_upcall; // JVMTI is doing a Java upcall, so JVMTI events must be hidden
328 int _jvmti_events_disabled; // JVMTI events disabled manually
329 bool _on_monitor_waited_event; // Avoid callee arg processing for enterSpecial when posting waited event
330 ObjectMonitor* _contended_entered_monitor; // Monitor for pending monitor_contended_entered callback
331 #endif
332
333 // JNI attach states:
334 enum JNIAttachStates {
335 _not_attaching_via_jni = 1, // thread is not attaching via JNI
336 _attaching_via_jni, // thread is attaching via JNI
337 _attached_via_jni // thread has attached via JNI
338 };
339
340 // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
341 // A native thread that is attaching via JNI starts with a value
342 // of _attaching_via_jni and transitions to _attached_via_jni.
343 volatile JNIAttachStates _jni_attach_state;
344
345 // In scope of an InternalOOMEMark?
346 bool _is_in_internal_oome_mark;
347
348 #if INCLUDE_JVMCI
349 // The _pending_* fields below are used to communicate extra information
350 // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
351
352 // Communicates the DeoptReason and DeoptAction of the uncommon trap
353 int _pending_deoptimization;
354
355 // Specifies whether the uncommon trap is to bci 0 of a synchronized method
356 // before the monitor has been acquired.
357 bool _pending_monitorenter;
358
359 // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
360 bool _pending_transfer_to_interpreter;
361
362 // An id of a speculation that JVMCI compiled code can use to further describe and
363 // uniquely identify the speculative optimization guarded by an uncommon trap.
364 // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
365 jlong _pending_failed_speculation;
366
367 // These fields are mutually exclusive in terms of live ranges.
368 union {
369 // Communicates the pc at which the most recent implicit exception occurred
370 // from the signal handler to a deoptimization stub.
371 address _implicit_exception_pc;
372
373 // Communicates an alternative call target to an i2c stub from a JavaCall .
374 address _alternate_call_target;
375 } _jvmci;
376
377 // The JVMCIRuntime in a JVMCI shared library
378 JVMCIRuntime* _libjvmci_runtime;
379
380 // Support for high precision, thread sensitive counters in JVMCI compiled code.
381 jlong* _jvmci_counters;
382
383 // Fast thread locals for use by JVMCI
384 jlong _jvmci_reserved0;
385 jlong _jvmci_reserved1;
386 oop _jvmci_reserved_oop0;
387
388 // This field is used to keep an nmethod visible to the GC so that it and its contained oops can
389 // be kept alive
390 nmethod* _live_nmethod;
391
392 public:
393 static jlong* _jvmci_old_thread_counters;
394 static void collect_counters(jlong* array, int length);
395
396 bool resize_counters(int current_size, int new_size);
397
398 static bool resize_all_jvmci_counters(int new_size);
399
400 void set_jvmci_reserved_oop0(oop value) {
401 _jvmci_reserved_oop0 = value;
402 }
403
404 oop get_jvmci_reserved_oop0() {
405 return _jvmci_reserved_oop0;
406 }
407
408 void set_jvmci_reserved0(jlong value) {
409 _jvmci_reserved0 = value;
410 }
411
412 jlong get_jvmci_reserved0() {
413 return _jvmci_reserved0;
414 }
415
416 void set_jvmci_reserved1(jlong value) {
417 _jvmci_reserved1 = value;
418 }
419
420 jlong get_jvmci_reserved1() {
421 return _jvmci_reserved1;
422 }
423
424 void set_live_nmethod(nmethod* nm) {
425 assert(_live_nmethod == nullptr, "only one");
426 _live_nmethod = nm;
427 }
428
429 void clear_live_nmethod() {
430 _live_nmethod = nullptr;
431 }
432
433 private:
434 #endif // INCLUDE_JVMCI
435
436 StackOverflow _stack_overflow_state;
437
438 void pretouch_stack();
439
440 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
441 // used to temp. parsing values into and out of the runtime system during exception handling for compiled
442 // code)
443 volatile oop _exception_oop; // Exception thrown in compiled code
444 volatile address _exception_pc; // PC where exception happened
445 volatile address _exception_handler_pc; // PC for handler of exception
446
447 private:
448 // support for JNI critical regions
449 jint _jni_active_critical; // count of entries into JNI critical region
450
451 // Checked JNI: function name requires exception check
452 char* _pending_jni_exception_check_fn;
453
454 // For deadlock detection.
455 int _depth_first_number;
456
457 // JVMTI PopFrame support
458 // This is set to popframe_pending to signal that top Java frame should be popped immediately
459 int _popframe_condition;
460
461 // If reallocation of scalar replaced objects fails, we throw OOM
462 // and during exception propagation, pop the top
463 // _frames_to_pop_failed_realloc frames, the ones that reference
464 // failed reallocations.
465 int _frames_to_pop_failed_realloc;
466
467 ContinuationEntry* _cont_entry;
468 intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub/upcall_stub/native_wrapper
469 // frame inside the continuation that we know about
470 int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
471
472 ObjectMonitor* _unlocked_inflated_monitor;
473
474 bool _can_call_java;
475
476 // This is the field we poke in the interpreter and native
477 // wrapper (Object.wait) to check for preemption.
478 address _preempt_alternate_return;
479 // When preempting on monitorenter we could have acquired the
480 // monitor after freezing all vthread frames. In that case we
481 // set this field so that in the preempt stub we call thaw again
482 // instead of unmounting.
483 bool _preemption_cancelled;
484 // For Object.wait() we set this field to know if we need to
485 // throw IE at the end of thawing before returning to Java.
486 bool _pending_interrupted_exception;
487 // We allow preemption on some klass initialization calls.
488 // We use this boolean to mark such calls.
489 bool _at_preemptable_init;
490
491 public:
492 bool preemption_cancelled() { return _preemption_cancelled; }
493 void set_preemption_cancelled(bool b) { _preemption_cancelled = b; }
494
495 bool pending_interrupted_exception() { return _pending_interrupted_exception; }
496 void set_pending_interrupted_exception(bool b) { _pending_interrupted_exception = b; }
497
498 bool preempting() { return _preempt_alternate_return != nullptr; }
499 void set_preempt_alternate_return(address val) { _preempt_alternate_return = val; }
500
501 bool at_preemptable_init() { return _at_preemptable_init; }
502 void set_at_preemptable_init(bool b) { _at_preemptable_init = b; }
503
504 #ifdef ASSERT
505 // Used for extra logging with -Xlog:continuation+preempt
506 InstanceKlass* _preempt_init_klass;
507
508 InstanceKlass* preempt_init_klass() { return _preempt_init_klass; }
509 void set_preempt_init_klass(InstanceKlass* ik) { _preempt_init_klass = ik; }
510
511 int _interp_at_preemptable_vmcall_cnt;
512 int interp_at_preemptable_vmcall_cnt() { return _interp_at_preemptable_vmcall_cnt; }
513
514 bool _interp_redoing_vm_call;
515 bool interp_redoing_vm_call() const { return _interp_redoing_vm_call; };
516
517 class AtRedoVMCall : public StackObj {
518 JavaThread* _thread;
519 public:
520 AtRedoVMCall(JavaThread* t) : _thread(t) {
521 assert(!_thread->_interp_redoing_vm_call, "");
522 _thread->_interp_redoing_vm_call = true;
523 _thread->_interp_at_preemptable_vmcall_cnt++;
524 assert(_thread->_interp_at_preemptable_vmcall_cnt > 0, "Unexpected count: %d",
525 _thread->_interp_at_preemptable_vmcall_cnt);
526 }
527 ~AtRedoVMCall() {
528 assert(_thread->_interp_redoing_vm_call, "");
529 _thread->_interp_redoing_vm_call = false;
530 _thread->_interp_at_preemptable_vmcall_cnt--;
531 assert(_thread->_interp_at_preemptable_vmcall_cnt >= 0, "Unexpected count: %d",
532 _thread->_interp_at_preemptable_vmcall_cnt);
533 }
534 };
535 #endif // ASSERT
536
537 private:
538 friend class VMThread;
539 friend class ThreadWaitTransition;
540 friend class VM_Exit;
541
542 // Stack watermark barriers.
543 StackWatermarks _stack_watermarks;
544
545 public:
546 inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
547
548 public:
549 // Constructor
550 JavaThread(MemTag mem_tag = mtThread); // delegating constructor
551 JavaThread(ThreadFunction entry_point, size_t stack_size = 0, MemTag mem_tag = mtThread);
552 ~JavaThread();
553
554 // Factory method to create a new JavaThread whose attach state is "is attaching"
555 static JavaThread* create_attaching_thread();
556
557 #ifdef ASSERT
558 // verify this JavaThread hasn't be published in the Threads::list yet
559 void verify_not_published();
560 #endif // ASSERT
561
562 StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
563
564 //JNI functiontable getter/setter for JVMTI jni function table interception API.
565 void set_jni_functions(struct JNINativeInterface_* functionTable) {
566 _jni_environment.functions = functionTable;
567 }
568 struct JNINativeInterface_* get_jni_functions() {
569 return (struct JNINativeInterface_ *)_jni_environment.functions;
570 }
571
572 // This function is called at thread creation to allow
573 // platform specific thread variables to be initialized.
574 void cache_global_variables();
575
576 // Executes Shutdown.shutdown()
577 void invoke_shutdown_hooks();
578
579 // Cleanup on thread exit
580 enum ExitType {
581 normal_exit,
582 jni_detach
583 };
584 void exit(bool destroy_vm, ExitType exit_type = normal_exit);
585
586 void cleanup_failed_attach_current_thread(bool is_daemon);
587
588 class NoJavaCodeMark : public StackObj {
589 friend JavaThread;
590 JavaThread* _target;
591 bool _orig;
592 public:
593 NoJavaCodeMark(JavaThread* t) : _target(t), _orig(t->_can_call_java) {
594 _target->_can_call_java = false;
595 }
596 ~NoJavaCodeMark() {
597 _target->_can_call_java = _orig;
598 }
599 };
600
601 // Testers
602 virtual bool is_Java_thread() const { return true; }
603 virtual bool can_call_java() const { return _can_call_java; }
604
605 virtual bool is_active_Java_thread() const;
606
607 // Thread oop. threadObj() can be null for initial JavaThread
608 // (or for threads attached via JNI)
609 oop threadObj() const;
610 void set_threadOopHandles(oop p);
611 oop vthread() const;
612 void set_vthread(oop p);
613 oop scopedValueCache() const;
614 void set_scopedValueCache(oop p);
615 void clear_scopedValueBindings();
616 oop jvmti_vthread() const;
617 void set_jvmti_vthread(oop p);
618 oop vthread_or_thread() const;
619
620 // Prepare thread and add to priority queue. If a priority is
621 // not specified, use the priority of the thread object. Threads_lock
622 // must be held while this function is called.
623 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
624
625 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; }
626 address saved_exception_pc() { return _saved_exception_pc; }
627
628 ThreadFunction entry_point() const { return _entry_point; }
629
630 // Allocates a new Java level thread object for this thread. thread_name may be null.
631 void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
632
633 // Last frame anchor routines
634
635 JavaFrameAnchor* frame_anchor(void) { return &_anchor; }
636
637 // last_Java_sp
638 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); }
639 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); }
640
641 // last_Java_pc
642
643 address last_Java_pc(void) { return _anchor.last_Java_pc(); }
644
645 // Safepoint support
646 inline JavaThreadState thread_state() const;
647 inline void set_thread_state(JavaThreadState s);
648 inline void set_thread_state_fence(JavaThreadState s); // fence after setting thread state
649 inline ThreadSafepointState* safepoint_state() const;
650 inline void set_safepoint_state(ThreadSafepointState* state);
651 inline bool is_at_poll_safepoint();
652
653 // JavaThread termination and lifecycle support:
654 void smr_delete();
655 bool on_thread_list() const { return _on_thread_list; }
656 void set_on_thread_list() { _on_thread_list = true; }
657
658 // thread has called JavaThread::exit(), thread's GC barrier is detached
659 // or thread is terminated
660 bool is_exiting() const;
661 // thread's GC barrier is NOT detached and thread is NOT terminated
662 bool is_oop_safe() const;
663 // thread is terminated (no longer on the threads list); the thread must
664 // be protected by a ThreadsListHandle to avoid potential crashes.
665 bool check_is_terminated(TerminatedTypes l_terminated) const {
666 return l_terminated == _thread_terminated || l_terminated == _vm_exited;
667 }
668 bool is_terminated() const;
669 void set_terminated(TerminatedTypes t);
670
671 void block_if_vm_exited();
672
673 bool doing_unsafe_access() { return _doing_unsafe_access; }
674 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; }
675
676 bool is_throwing_unsafe_access_error() { return _throwing_unsafe_access_error; }
677 void set_throwing_unsafe_access_error(bool val) { _throwing_unsafe_access_error = val; }
678
679 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; }
680 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
681
682 SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
683
684 static ByteSize polling_word_offset() {
685 ByteSize offset = byte_offset_of(Thread, _poll_data) +
686 byte_offset_of(SafepointMechanism::ThreadData, _polling_word);
687 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
688 assert(in_bytes(offset) < 128, "Offset >= 128");
689 return offset;
690 }
691
692 static ByteSize polling_page_offset() {
693 ByteSize offset = byte_offset_of(Thread, _poll_data) +
694 byte_offset_of(SafepointMechanism::ThreadData, _polling_page);
695 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
696 assert(in_bytes(offset) < 128, "Offset >= 128");
697 return offset;
698 }
699
700 void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
701
702 // Continuation support
703 ContinuationEntry* last_continuation() const { return _cont_entry; }
704 void set_cont_fastpath(intptr_t* x) { _cont_fastpath = x; }
705 void push_cont_fastpath(intptr_t* sp) { if (sp > _cont_fastpath) _cont_fastpath = sp; }
706 void set_cont_fastpath_thread_state(bool x) { _cont_fastpath_thread_state = (int)x; }
707 intptr_t* raw_cont_fastpath() const { return _cont_fastpath; }
708 bool cont_fastpath() const { return _cont_fastpath == nullptr && _cont_fastpath_thread_state != 0; }
709 bool cont_fastpath_thread_state() const { return _cont_fastpath_thread_state != 0; }
710
711 // Support for SharedRuntime::monitor_exit_helper()
712 ObjectMonitor* unlocked_inflated_monitor() const { return _unlocked_inflated_monitor; }
713 void clear_unlocked_inflated_monitor() {
714 _unlocked_inflated_monitor = nullptr;
715 }
716
717 inline bool is_vthread_mounted() const;
718 inline const ContinuationEntry* vthread_continuation() const;
719
720 private:
721 DEBUG_ONLY(void verify_frame_info();)
722
723 // Support for thread handshake operations
724 HandshakeState _handshake;
725 public:
726 HandshakeState* handshake_state() { return &_handshake; }
727
728 // A JavaThread can always safely operate on it self and other threads
729 // can do it safely if they are the active handshaker.
730 bool is_handshake_safe_for(Thread* th) const {
731 return _handshake.active_handshaker() == th || this == th;
732 }
733
734 // Suspend/resume support for JavaThread
735 // higher-level suspension/resume logic called by the public APIs
736 private:
737 SuspendResumeManager _suspend_resume_manager;
738 public:
739 bool java_suspend(bool register_vthread_SR);
740 bool java_resume(bool register_vthread_SR);
741 bool is_suspended() { return _suspend_resume_manager.is_suspended(); }
742 SuspendResumeManager* suspend_resume_manager() { return &_suspend_resume_manager; }
743
744 // Check for async exception in addition to safepoint.
745 static void check_special_condition_for_native_trans(JavaThread *thread);
746
747 // Synchronize with another thread that is deoptimizing objects of the
748 // current thread, i.e. reverts optimizations based on escape analysis.
749 void wait_for_object_deoptimization();
750
751 private:
752 bool _is_in_vthread_transition; // thread is in virtual thread mount state transition
753 JVMTI_ONLY(bool _is_vthread_transition_disabler;) // thread currently disabled vthread transitions
754 DEBUG_ONLY(bool _is_disabler_at_start;) // thread at process of disabling vthread transitions
755 public:
756 bool is_in_vthread_transition() const;
757 void set_is_in_vthread_transition(bool val);
758 JVMTI_ONLY(bool is_vthread_transition_disabler() const { return _is_vthread_transition_disabler; })
759 JVMTI_ONLY(void set_is_vthread_transition_disabler(bool val);)
760 #ifdef ASSERT
761 bool is_disabler_at_start() const { return _is_disabler_at_start; }
762 void set_is_disabler_at_start(bool val);
763 #endif
764
765 #if INCLUDE_JVMTI
766 inline bool set_carrier_thread_suspended();
767 inline bool clear_carrier_thread_suspended();
768
769 bool is_carrier_thread_suspended() const {
770 return AtomicAccess::load(&_carrier_thread_suspended);
771 }
772
773 bool is_disable_suspend() const { return _is_disable_suspend; }
774 void toggle_is_disable_suspend() { _is_disable_suspend = !_is_disable_suspend; }
775
776 bool is_in_java_upcall() const { return _is_in_java_upcall; }
777 void toggle_is_in_java_upcall() { _is_in_java_upcall = !_is_in_java_upcall; }
778
779 void disable_jvmti_events() { _jvmti_events_disabled++; }
780 void enable_jvmti_events() { _jvmti_events_disabled--; }
781
782 // Temporarily skip posting JVMTI events for safety reasons when executions is in a critical section:
783 // - is in a vthread transition (_is_in_vthread_transition)
784 // - is in an interruptLock or similar critical section (_is_disable_suspend)
785 // - JVMTI is making a Java upcall (_is_in_java_upcall)
786 bool should_hide_jvmti_events() const {
787 return _is_in_vthread_transition || _is_disable_suspend || _is_in_java_upcall || _jvmti_events_disabled != 0;
788 }
789
790 bool on_monitor_waited_event() { return _on_monitor_waited_event; }
791 void set_on_monitor_waited_event(bool val) { _on_monitor_waited_event = val; }
792
793 bool pending_contended_entered_event() { return _contended_entered_monitor != nullptr; }
794 ObjectMonitor* contended_entered_monitor() { return _contended_entered_monitor; }
795 #endif
796
797 void set_contended_entered_monitor(ObjectMonitor* val) NOT_JVMTI_RETURN JVMTI_ONLY({ _contended_entered_monitor = val; })
798
799 // Support for object deoptimization and JFR suspension
800 void handle_special_runtime_exit_condition();
801 bool has_special_runtime_exit_condition() {
802 return (_suspend_flags & _obj_deopt) != 0;
803 }
804
805 // Accessors for vframe array top
806 // The linked list of vframe arrays are sorted on sp. This means when we
807 // unpack the head must contain the vframe array to unpack.
808 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
809 vframeArray* vframe_array_head() const { return _vframe_array_head; }
810
811 // Side structure for deferring update of java frame locals until deopt occurs
812 JvmtiDeferredUpdates* deferred_updates() const { return _jvmti_deferred_updates; }
813 void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
814
815 // These only really exist to make debugging deopt problems simpler
816
817 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
818 vframeArray* vframe_array_last() const { return _vframe_array_last; }
819
820 // The special resourceMark used during deoptimization
821
822 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; }
823 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; }
824
825 void set_deopt_compiled_method(nmethod* nm) { _deopt_nmethod = nm; }
826 nmethod* deopt_compiled_method() { return _deopt_nmethod; }
827
828 Method* callee_target() const { return _callee_target; }
829 void set_callee_target (Method* x) { _callee_target = x; }
830
831 // Oop results of vm runtime calls
832 oop vm_result_oop() const { return _vm_result_oop; }
833 void set_vm_result_oop(oop x) { _vm_result_oop = x; }
834
835 void set_vm_result_metadata(Metadata* x) { _vm_result_metadata = x; }
836
837 // Is thread in scope of an InternalOOMEMark?
838 bool is_in_internal_oome_mark() const { return _is_in_internal_oome_mark; }
839 void set_is_in_internal_oome_mark(bool b) { _is_in_internal_oome_mark = b; }
840
841 #if INCLUDE_JVMCI
842 jlong pending_failed_speculation() const { return _pending_failed_speculation; }
843 void set_pending_monitorenter(bool b) { _pending_monitorenter = b; }
844 void set_pending_deoptimization(int reason) { _pending_deoptimization = reason; }
845 void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
846 void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
847 void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == nullptr, "must be"); _jvmci._alternate_call_target = a; }
848 void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == nullptr, "must be"); _jvmci._implicit_exception_pc = a; }
849
850 JVMCIRuntime* libjvmci_runtime() const { return _libjvmci_runtime; }
851 void set_libjvmci_runtime(JVMCIRuntime* rt) {
852 assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
853 _libjvmci_runtime = rt;
854 }
855 #endif // INCLUDE_JVMCI
856
857 // Exception handling for compiled methods
858 oop exception_oop() const;
859 address exception_pc() const { return _exception_pc; }
860
861 void set_exception_oop(oop o);
862 void set_exception_pc(address a) { _exception_pc = a; }
863 void set_exception_handler_pc(address a) { _exception_handler_pc = a; }
864
865 void clear_exception_oop_and_pc() {
866 set_exception_oop(nullptr);
867 set_exception_pc(nullptr);
868 }
869
870 // Check if address is in the usable part of the stack (excludes protected
871 // guard pages). Can be applied to any thread and is an approximation for
872 // using is_in_live_stack when the query has to happen from another thread.
873 bool is_in_usable_stack(address adr) const {
874 return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
875 }
876
877 // Misc. accessors/mutators
878 static ByteSize scopedValueCache_offset() { return byte_offset_of(JavaThread, _scopedValueCache); }
879
880 // For assembly stub generation
881 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj); }
882 static ByteSize vthread_offset() { return byte_offset_of(JavaThread, _vthread); }
883 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment); }
884 static ByteSize pending_jni_exception_check_fn_offset() {
885 return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
886 }
887 static ByteSize last_Java_sp_offset() {
888 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
889 }
890 static ByteSize last_Java_pc_offset() {
891 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
892 }
893 static ByteSize frame_anchor_offset() {
894 return byte_offset_of(JavaThread, _anchor);
895 }
896 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target); }
897 static ByteSize vm_result_oop_offset() { return byte_offset_of(JavaThread, _vm_result_oop); }
898 static ByteSize vm_result_metadata_offset() { return byte_offset_of(JavaThread, _vm_result_metadata); }
899 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state); }
900 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc); }
901 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread); }
902 #if INCLUDE_JVMCI
903 static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
904 static ByteSize pending_monitorenter_offset() { return byte_offset_of(JavaThread, _pending_monitorenter); }
905 static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
906 static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
907 static ByteSize jvmci_counters_offset() { return byte_offset_of(JavaThread, _jvmci_counters); }
908 #endif // INCLUDE_JVMCI
909 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop); }
910 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc); }
911 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); }
912
913 static ByteSize active_handles_offset() { return byte_offset_of(JavaThread, _active_handles); }
914
915 // StackOverflow offsets
916 static ByteSize stack_overflow_limit_offset() {
917 return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
918 }
919 static ByteSize stack_guard_state_offset() {
920 return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
921 }
922 static ByteSize reserved_stack_activation_offset() {
923 return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
924 }
925 static ByteSize shadow_zone_safe_limit() {
926 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
927 }
928 static ByteSize shadow_zone_growth_watermark() {
929 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
930 }
931
932 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags); }
933
934 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
935 static ByteSize should_post_on_exceptions_flag_offset() {
936 return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
937 }
938 static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
939 NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset() { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
940
941 static ByteSize monitor_owner_id_offset() { return byte_offset_of(JavaThread, _monitor_owner_id); }
942
943 static ByteSize cont_entry_offset() { return byte_offset_of(JavaThread, _cont_entry); }
944 static ByteSize cont_fastpath_offset() { return byte_offset_of(JavaThread, _cont_fastpath); }
945 static ByteSize preemption_cancelled_offset() { return byte_offset_of(JavaThread, _preemption_cancelled); }
946 static ByteSize preempt_alternate_return_offset() { return byte_offset_of(JavaThread, _preempt_alternate_return); }
947 DEBUG_ONLY(static ByteSize interp_at_preemptable_vmcall_cnt_offset() { return byte_offset_of(JavaThread, _interp_at_preemptable_vmcall_cnt); })
948 static ByteSize unlocked_inflated_monitor_offset() { return byte_offset_of(JavaThread, _unlocked_inflated_monitor); }
949 static ByteSize is_in_vthread_transition_offset() { return byte_offset_of(JavaThread, _is_in_vthread_transition); }
950
951 #if INCLUDE_JVMTI
952 static ByteSize is_disable_suspend_offset() { return byte_offset_of(JavaThread, _is_disable_suspend); }
953 #endif
954
955 // Returns the jni environment for this thread
956 JNIEnv* jni_environment() { return &_jni_environment; }
957
958 // Returns the current thread as indicated by the given JNIEnv.
959 // We don't assert it is Thread::current here as that is done at the
960 // external JNI entry points where the JNIEnv is passed into the VM.
961 static JavaThread* thread_from_jni_environment(JNIEnv* env) {
962 JavaThread* current = reinterpret_cast<JavaThread*>(((intptr_t)env - in_bytes(jni_environment_offset())));
963 // We can't normally get here in a thread that has completed its
964 // execution and so "is_terminated", except when the call is from
965 // AsyncGetCallTrace, which can be triggered by a signal at any point in
966 // a thread's lifecycle. A thread is also considered terminated if the VM
967 // has exited, so we have to check this and block in case this is a daemon
968 // thread returning to the VM (the JNI DirectBuffer entry points rely on
969 // this).
970 if (current->is_terminated()) {
971 current->block_if_vm_exited();
972 }
973 return current;
974 }
975
976 // JNI critical regions. These can nest.
977 bool in_critical() { return _jni_active_critical > 0; }
978 bool in_last_critical() { return _jni_active_critical == 1; }
979 inline void enter_critical();
980 void exit_critical() {
981 assert(Thread::current() == this, "this must be current thread");
982 _jni_active_critical--;
983 assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
984 }
985
986 // Atomic version; invoked by a thread other than the owning thread.
987 bool in_critical_atomic() { return AtomicAccess::load(&_jni_active_critical) > 0; }
988
989 // Checked JNI: is the programmer required to check for exceptions, if so specify
990 // which function name. Returning to a Java frame should implicitly clear the
991 // pending check, this is done for Native->Java transitions (i.e. user JNI code).
992 // VM->Java transitions are not cleared, it is expected that JNI code enclosed
993 // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
994 bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != nullptr; }
995 void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = nullptr; }
996 const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
997 void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
998
999 // For deadlock detection
1000 int depth_first_number() { return _depth_first_number; }
1001 void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1002
1003 public:
1004 bool in_deopt_handler() const { return _in_deopt_handler > 0; }
1005 void inc_in_deopt_handler() { _in_deopt_handler++; }
1006 void dec_in_deopt_handler() {
1007 assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1008 if (_in_deopt_handler > 0) { // robustness
1009 _in_deopt_handler--;
1010 }
1011 }
1012
1013 private:
1014 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1015
1016 // factor out low-level mechanics for use in both normal and error cases
1017 const char* get_thread_name_string(char* buf = nullptr, int buflen = 0) const;
1018
1019 public:
1020
1021 // Frame iteration; calls the function f for all frames on the stack
1022 void frames_do(void f(frame*, const RegisterMap*));
1023
1024 // Memory operations
1025 void oops_do_frames(OopClosure* f, NMethodClosure* cf);
1026 void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
1027
1028 // GC operations
1029 virtual void nmethods_do(NMethodClosure* cf);
1030
1031 // RedefineClasses Support
1032 void metadata_do(MetadataClosure* f);
1033
1034 // Debug method asserting thread states are correct during a handshake operation.
1035 DEBUG_ONLY(void verify_states_for_handshake();)
1036
1037 // Misc. operations
1038 const char* name() const;
1039 const char* name_raw() const;
1040 const char* type_name() const { return "JavaThread"; }
1041 static const char* name_for(oop thread_obj);
1042
1043 void print_on(outputStream* st, bool print_extended_info) const;
1044 void print_on(outputStream* st) const { print_on(st, false); }
1045 void print() const;
1046 void print_thread_state_on(outputStream*) const;
1047 void print_on_error(outputStream* st, char* buf, int buflen) const;
1048 void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1049 void verify();
1050
1051 // Accessing frames
1052 frame last_frame() {
1053 _anchor.make_walkable();
1054 return pd_last_frame();
1055 }
1056 javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
1057
1058 frame carrier_last_frame(RegisterMap* reg_map);
1059 javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
1060
1061 frame vthread_last_frame();
1062 javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
1063
1064 frame platform_thread_last_frame(RegisterMap* reg_map);
1065 javaVFrame* platform_thread_last_java_vframe(RegisterMap* reg_map) {
1066 return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
1067 }
1068
1069 javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
1070
1071 // Returns method at 'depth' java or native frames down the stack
1072 // Used for security checks
1073 Klass* security_get_caller_class(int depth);
1074
1075 // Print stack trace in external format
1076 // These variants print carrier/platform thread information only.
1077 void print_stack_on(outputStream* st);
1078 void print_stack() { print_stack_on(tty); }
1079 // This prints the currently mounted virtual thread.
1080 void print_vthread_stack_on(outputStream* st);
1081 // This prints the active stack: either carrier/platform or virtual.
1082 void print_active_stack_on(outputStream* st);
1083 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1084 // This is the external format from above, but selecting the platform
1085 // or vthread as applicable.
1086 void print_jni_stack();
1087
1088 // Print stack traces in various internal formats
1089 void trace_stack() PRODUCT_RETURN;
1090 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN;
1091 void trace_frames() PRODUCT_RETURN;
1092
1093 // Print an annotated view of the stack frames
1094 void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1095 void validate_frame_layout() {
1096 print_frame_layout(0, true);
1097 }
1098
1099 // Function for testing deoptimization
1100 void deoptimize();
1101 void make_zombies();
1102
1103 void deoptimize_marked_methods();
1104
1105 public:
1106 // Returns the running thread as a JavaThread
1107 static JavaThread* current() {
1108 return JavaThread::cast(Thread::current());
1109 }
1110
1111 // Returns the current thread as a JavaThread, or nullptr if not attached
1112 static inline JavaThread* current_or_null();
1113
1114 // Casts
1115 static JavaThread* cast(Thread* t) {
1116 assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1117 return static_cast<JavaThread*>(t);
1118 }
1119
1120 static const JavaThread* cast(const Thread* t) {
1121 assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1122 return static_cast<const JavaThread*>(t);
1123 }
1124
1125 // Returns the active Java thread. Do not use this if you know you are calling
1126 // from a JavaThread, as it's slower than JavaThread::current. If called from
1127 // the VMThread, it also returns the JavaThread that instigated the VMThread's
1128 // operation. You may not want that either.
1129 static JavaThread* active();
1130
1131 protected:
1132 virtual void pre_run();
1133 virtual void run();
1134 void thread_main_inner();
1135 virtual void post_run();
1136
1137 public:
1138 // Thread local information maintained by JVMTI.
1139 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; }
1140 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1141 // getter is used to get this JavaThread's JvmtiThreadState if it has
1142 // one which means null can be returned. JvmtiThreadState::state_for()
1143 // is used to get the specified JavaThread's JvmtiThreadState if it has
1144 // one or it allocates a new JvmtiThreadState for the JavaThread and
1145 // returns it. JvmtiThreadState::state_for() will return null only if
1146 // the specified JavaThread is exiting.
1147 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; }
1148 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1149
1150 #if INCLUDE_JVMTI
1151 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1152 JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1153 #endif
1154
1155 // JVMTI PopFrame support
1156 // Setting and clearing popframe_condition
1157 // All of these enumerated values are bits. popframe_pending
1158 // indicates that a PopFrame() has been requested and not yet been
1159 // completed. popframe_processing indicates that that PopFrame() is in
1160 // the process of being completed. popframe_force_deopt_reexecution_bit
1161 // indicates that special handling is required when returning to a
1162 // deoptimized caller.
1163 enum PopCondition {
1164 popframe_inactive = 0x00,
1165 popframe_pending_bit = 0x01,
1166 popframe_processing_bit = 0x02,
1167 popframe_force_deopt_reexecution_bit = 0x04
1168 };
1169 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; }
1170 void set_popframe_condition(PopCondition c) { _popframe_condition = c; }
1171 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; }
1172 void clear_popframe_condition() { _popframe_condition = popframe_inactive; }
1173 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); }
1174 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; }
1175 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1176
1177 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); }
1178 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; }
1179 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; }
1180
1181 int frames_to_pop_failed_realloc() const { return _frames_to_pop_failed_realloc; }
1182 void set_frames_to_pop_failed_realloc(int nb) { _frames_to_pop_failed_realloc = nb; }
1183 void dec_frames_to_pop_failed_realloc() { _frames_to_pop_failed_realloc--; }
1184
1185 private:
1186 // Saved incoming arguments to popped frame.
1187 // Used only when popped interpreted frame returns to deoptimized frame.
1188 void* _popframe_preserved_args;
1189 int _popframe_preserved_args_size;
1190
1191 public:
1192 void popframe_preserve_args(ByteSize size_in_bytes, void* start);
1193 void* popframe_preserved_args();
1194 ByteSize popframe_preserved_args_size();
1195 WordSize popframe_preserved_args_size_in_words();
1196 void popframe_free_preserved_args();
1197
1198
1199 private:
1200 JvmtiThreadState *_jvmti_thread_state;
1201
1202 // Used by the interpreter in fullspeed mode for frame pop, method
1203 // entry, method exit and single stepping support. This field is
1204 // only set to non-zero at a safepoint or using a direct handshake
1205 // (see EnterInterpOnlyModeHandshakeClosure).
1206 // It can be set to zero asynchronously to this threads execution (i.e., without
1207 // safepoint/handshake or a lock) so we have to be very careful.
1208 // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1209 // This field is checked by the interpreter which expects it to be an integer.
1210 int _interp_only_mode;
1211
1212 public:
1213 // used by the interpreter for fullspeed debugging support (see above)
1214 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1215 bool is_interp_only_mode() { return (_interp_only_mode != 0); }
1216 void set_interp_only_mode(bool val) { _interp_only_mode = val ? 1 : 0; }
1217
1218 // support for cached flag that indicates whether exceptions need to be posted for this thread
1219 // if this is false, we can avoid deoptimizing when events are thrown
1220 // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1221 private:
1222 int _should_post_on_exceptions_flag;
1223
1224 public:
1225 void set_should_post_on_exceptions_flag(int val) { _should_post_on_exceptions_flag = val; }
1226
1227 private:
1228 ThreadStatistics *_thread_stat;
1229
1230 public:
1231 ThreadStatistics* get_thread_stat() const { return _thread_stat; }
1232
1233 // Return a blocker object for which this thread is blocked parking.
1234 oop current_park_blocker();
1235
1236 private:
1237 static size_t _stack_size_at_create;
1238
1239 public:
1240 static inline size_t stack_size_at_create(void) {
1241 return _stack_size_at_create;
1242 }
1243 static inline void set_stack_size_at_create(size_t value) {
1244 _stack_size_at_create = value;
1245 }
1246
1247 // Machine dependent stuff
1248 #include OS_CPU_HEADER(javaThread)
1249
1250 // JSR166 per-thread parker
1251 private:
1252 Parker _parker;
1253 public:
1254 Parker* parker() { return &_parker; }
1255
1256 public:
1257 // clearing/querying jni attach status
1258 bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1259 bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1260 inline void set_done_attaching_via_jni();
1261
1262 // Stack dump assistance:
1263 // Track the class we want to initialize but for which we have to wait
1264 // on its init_lock() because it is already being initialized.
1265 void set_class_to_be_initialized(InstanceKlass* k);
1266 InstanceKlass* class_to_be_initialized() const;
1267
1268 // The most recent active <clinit> invocation is tracked by this variable.
1269 // The setter returns the previous value, so it can be restored later if needed.
1270 InstanceKlass* set_class_being_initialized(InstanceKlass* k);
1271 InstanceKlass* class_being_initialized() const;
1272
1273 private:
1274 InstanceKlass* _class_to_be_initialized;
1275 InstanceKlass* _class_being_initialized;
1276
1277 // java.lang.Thread.sleep support
1278 ParkEvent * _SleepEvent;
1279
1280 #if INCLUDE_JFR
1281 // Support for jdk.VirtualThreadPinned event
1282 freeze_result _last_freeze_fail_result;
1283 Ticks _last_freeze_fail_time;
1284 #endif
1285
1286 public:
1287 bool sleep(jlong millis);
1288 bool sleep_nanos(jlong nanos);
1289
1290 // java.lang.Thread interruption support
1291 void interrupt();
1292 bool is_interrupted(bool clear_interrupted);
1293
1294 #if INCLUDE_JFR
1295 // Support for jdk.VirtualThreadPinned event
1296 freeze_result last_freeze_fail_result() { return _last_freeze_fail_result; }
1297 Ticks& last_freeze_fail_time() { return _last_freeze_fail_time; }
1298 void set_last_freeze_fail_result(freeze_result result);
1299 #endif
1300 void post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) NOT_JFR_RETURN();
1301
1302
1303 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
1304 // the Java code in Object::wait which are not present in RawMonitorWait.
1305 bool get_and_clear_interrupted();
1306
1307 private:
1308
1309 #ifdef MACOS_AARCH64
1310 friend class ThreadWXEnable;
1311 friend class PosixSignals;
1312
1313 ThreadWXEnable* _cur_wx_enable;
1314 WXMode* _cur_wx_mode;
1315 #endif
1316
1317 LockStack _lock_stack;
1318 OMCache _om_cache;
1319
1320 public:
1321 LockStack& lock_stack() { return _lock_stack; }
1322
1323 static ByteSize lock_stack_offset() { return byte_offset_of(JavaThread, _lock_stack); }
1324 // Those offsets are used in code generators to access the LockStack that is embedded in this
1325 // JavaThread structure. Those accesses are relative to the current thread, which
1326 // is typically in a dedicated register.
1327 static ByteSize lock_stack_top_offset() { return lock_stack_offset() + LockStack::top_offset(); }
1328 static ByteSize lock_stack_base_offset() { return lock_stack_offset() + LockStack::base_offset(); }
1329
1330 static ByteSize om_cache_offset() { return byte_offset_of(JavaThread, _om_cache); }
1331 static ByteSize om_cache_oops_offset() { return om_cache_offset() + OMCache::entries_offset(); }
1332
1333 void om_set_monitor_cache(ObjectMonitor* monitor);
1334 void om_clear_monitor_cache();
1335 ObjectMonitor* om_get_from_monitor_cache(oop obj);
1336
1337 static OopStorage* thread_oop_storage();
1338
1339 static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1340
1341 // Helper function to create the java.lang.Thread object for a
1342 // VM-internal thread. The thread will have the given name and be
1343 // part of the System ThreadGroup.
1344 static Handle create_system_thread_object(const char* name, TRAPS);
1345
1346 // Helper function to start a VM-internal daemon thread.
1347 // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1348 static void start_internal_daemon(JavaThread* current, JavaThread* target,
1349 Handle thread_oop, ThreadPriority prio);
1350
1351 // Helper function to do vm_exit_on_initialization for osthread
1352 // resource allocation failure.
1353 static void vm_exit_on_osthread_failure(JavaThread* thread);
1354
1355 // Deferred OopHandle release support
1356 private:
1357 // List of OopHandles to be released - guarded by the Service_lock.
1358 static OopHandleList* _oop_handle_list;
1359 // Add our OopHandles to the list for the service thread to release.
1360 void add_oop_handles_for_release();
1361 // Called by the ServiceThread to release the OopHandles.
1362 static void release_oop_handles();
1363 // Called by the ServiceThread to poll if there are any OopHandles to release.
1364 // Called when holding the Service_lock.
1365 static bool has_oop_handles_to_release() {
1366 return _oop_handle_list != nullptr;
1367 }
1368 };
1369
1370 inline JavaThread* JavaThread::current_or_null() {
1371 Thread* current = Thread::current_or_null();
1372 return current != nullptr ? JavaThread::cast(current) : nullptr;
1373 }
1374
1375 class UnlockFlagSaver {
1376 private:
1377 JavaThread* _thread;
1378 bool _do_not_unlock;
1379 public:
1380 UnlockFlagSaver(JavaThread* t) {
1381 _thread = t;
1382 _do_not_unlock = t->do_not_unlock_if_synchronized();
1383 t->set_do_not_unlock_if_synchronized(false);
1384 }
1385 ~UnlockFlagSaver() {
1386 _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1387 }
1388 };
1389
1390 class JNIHandleMark : public StackObj {
1391 JavaThread* _thread;
1392 public:
1393 JNIHandleMark(JavaThread* thread) : _thread(thread) {
1394 thread->push_jni_handle_block();
1395 }
1396 ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1397 };
1398
1399 class NoPreemptMark {
1400 ContinuationEntry* _ce;
1401 bool _unpin;
1402 public:
1403 NoPreemptMark(JavaThread* thread, bool ignore_mark = false) : _ce(thread->last_continuation()), _unpin(false) {
1404 if (_ce != nullptr && !ignore_mark) _unpin = _ce->pin();
1405 }
1406 ~NoPreemptMark() { if (_unpin) _ce->unpin(); }
1407 };
1408
1409 class ThreadOnMonitorWaitedEvent {
1410 JavaThread* _thread;
1411 public:
1412 ThreadOnMonitorWaitedEvent(JavaThread* thread) : _thread(thread) {
1413 JVMTI_ONLY(_thread->set_on_monitor_waited_event(true);)
1414 }
1415 ~ThreadOnMonitorWaitedEvent() { JVMTI_ONLY(_thread->set_on_monitor_waited_event(false);) }
1416 };
1417
1418 class ThreadInClassInitializer : public StackObj {
1419 JavaThread* _thread;
1420 InstanceKlass* _previous;
1421 public:
1422 ThreadInClassInitializer(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1423 _previous = _thread->class_being_initialized();
1424 _thread->set_class_being_initialized(ik);
1425 }
1426 ~ThreadInClassInitializer() {
1427 _thread->set_class_being_initialized(_previous);
1428 }
1429 };
1430
1431 class ThrowingUnsafeAccessError : public StackObj {
1432 JavaThread* _thread;
1433 bool _prev;
1434 public:
1435 ThrowingUnsafeAccessError(JavaThread* thread) :
1436 _thread(thread),
1437 _prev(thread->is_throwing_unsafe_access_error()) {
1438 _thread->set_throwing_unsafe_access_error(true);
1439 }
1440 ~ThrowingUnsafeAccessError() {
1441 _thread->set_throwing_unsafe_access_error(_prev);
1442 }
1443 };
1444
1445 #endif // SHARE_RUNTIME_JAVATHREAD_HPP