1 /*
2 * Copyright (c) 1997, 2025, 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/stackWatermarkSet.hpp"
42 #include "runtime/stackOverflow.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
85 class JavaThread: public Thread {
86 friend class VMStructs;
87 friend class JVMCIVMStructs;
88 friend class WhiteBox;
89 friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
90 friend class HandshakeState;
91 friend class Continuation;
92 friend class Threads;
93 friend class ServiceThread; // for deferred OopHandle release access
94 private:
95 bool _on_thread_list; // Is set when this JavaThread is added to the Threads list
96
97 // All references to Java objects managed via OopHandles. These
98 // have to be released by the ServiceThread after the JavaThread has
99 // terminated - see add_oop_handles_for_release().
100 OopHandle _threadObj; // The Java level thread object
101 OopHandle _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
102 OopHandle _jvmti_vthread;
103 OopHandle _scopedValueCache;
104
105 static OopStorage* _thread_oop_storage;
106
107 #ifdef ASSERT
108 private:
109 int _java_call_counter;
110
111 public:
112 int java_call_counter() { return _java_call_counter; }
113 void inc_java_call_counter() { _java_call_counter++; }
114 void dec_java_call_counter() {
115 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
116 _java_call_counter--;
117 }
118 private: // restore original namespace restriction
119 #endif // ifdef ASSERT
120
121 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state
122
123 ThreadFunction _entry_point;
124
125 JNIEnv _jni_environment;
126
127 // Deopt support
128 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization
129
130 nmethod* _deopt_nmethod; // nmethod that is currently being deoptimized
131 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays
132 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped
133 // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
134 // will be carried out as soon as possible which, in most cases, is just before deoptimization of
135 // the frame, when control returns to it.
136 JvmtiDeferredUpdates* _jvmti_deferred_updates;
137
138 // Handshake value for fixing 6243940. We need a place for the i2c
139 // adapter to store the callee Method*. This value is NEVER live
140 // across a gc point so it does NOT have to be gc'd
141 // The handshake is open ended since we can't be certain that it will
142 // be nulled. This is because we rarely ever see the race and end up
143 // in handle_wrong_method which is the backend of the handshake. See
144 // code in i2c adapters and handle_wrong_method.
145
146 Method* _callee_target;
147
148 // Used to pass back results to the interpreter or generated code running Java code.
149 oop _vm_result_oop; // oop result is GC-preserved
150 Metadata* _vm_result_metadata; // non-oop result
151 oop _return_buffered_value; // buffered value being returned
152
153 // See ReduceInitialCardMarks: this holds the precise space interval of
154 // the most recent slow path allocation for which compiled code has
155 // elided card-marks for performance along the fast-path.
156 MemRegion _deferred_card_mark;
157
158 ObjectMonitor* volatile _current_pending_monitor; // ObjectMonitor this thread is waiting to lock
159 bool _current_pending_monitor_is_from_java; // locking is from Java code
160 ObjectMonitor* volatile _current_waiting_monitor; // ObjectMonitor on which this thread called Object.wait()
161
162 // Active_handles points to a block of handles
163 JNIHandleBlock* _active_handles;
164
165 // One-element thread local free list
166 JNIHandleBlock* _free_handle_block;
167
168 // ID used as owner for inflated monitors. Same as the j.l.Thread.tid of the
169 // current _vthread object, except during creation of the primordial and JNI
170 // attached thread cases where this field can have a temporary value.
171 int64_t _monitor_owner_id;
172
173 public:
174 void set_monitor_owner_id(int64_t id) {
175 ThreadIdentifier::verify_id(id);
176 _monitor_owner_id = id;
177 }
178 int64_t monitor_owner_id() const {
179 int64_t id = _monitor_owner_id;
180 ThreadIdentifier::verify_id(id);
181 return id;
182 }
183
184 // For tracking the heavyweight monitor the thread is pending on.
185 ObjectMonitor* current_pending_monitor() {
186 // Use Atomic::load() to prevent data race between concurrent modification and
187 // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
188 // Especially, reloading pointer from thread after null check must be prevented.
189 return Atomic::load(&_current_pending_monitor);
190 }
191 void set_current_pending_monitor(ObjectMonitor* monitor) {
192 Atomic::store(&_current_pending_monitor, monitor);
193 }
194 void set_current_pending_monitor_is_from_java(bool from_java) {
195 _current_pending_monitor_is_from_java = from_java;
196 }
197 bool current_pending_monitor_is_from_java() {
198 return _current_pending_monitor_is_from_java;
199 }
200 ObjectMonitor* current_waiting_monitor() {
201 // See the comment in current_pending_monitor() above.
202 return Atomic::load(&_current_waiting_monitor);
203 }
204 void set_current_waiting_monitor(ObjectMonitor* monitor) {
205 Atomic::store(&_current_waiting_monitor, monitor);
206 }
207
208 // JNI handle support
209 JNIHandleBlock* active_handles() const { return _active_handles; }
210 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
211 JNIHandleBlock* free_handle_block() const { return _free_handle_block; }
212 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
213
214 void push_jni_handle_block();
215 void pop_jni_handle_block();
216
217 private:
218 enum SuspendFlags {
219 // NOTE: avoid using the sign-bit as cc generates different test code
220 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077
221 _obj_deopt = 0x00000008U // suspend for object reallocation and relocking for JVMTI agent
222 };
223
224 // various suspension related flags - atomically updated
225 volatile uint32_t _suspend_flags;
226
227 inline void set_suspend_flag(SuspendFlags f);
228 inline void clear_suspend_flag(SuspendFlags f);
229
230 public:
231 inline void set_obj_deopt_flag();
232 inline void clear_obj_deopt_flag();
233 bool is_obj_deopt_suspend() { return (_suspend_flags & _obj_deopt) != 0; }
234
235 // Asynchronous exception support
236 private:
237 friend class InstallAsyncExceptionHandshakeClosure;
238 friend class AsyncExceptionHandshakeClosure;
239 friend class HandshakeState;
240
241 void handle_async_exception(oop java_throwable);
242 public:
243 void install_async_exception(AsyncExceptionHandshakeClosure* aec = nullptr);
244 bool has_async_exception_condition();
245 inline void set_pending_unsafe_access_error();
246 static void send_async_exception(JavaThread* jt, oop java_throwable);
247
248 class NoAsyncExceptionDeliveryMark : public StackObj {
249 friend JavaThread;
250 JavaThread *_target;
251 inline NoAsyncExceptionDeliveryMark(JavaThread *t);
252 inline ~NoAsyncExceptionDeliveryMark();
253 };
254
255 // Safepoint support
256 public: // Expose _thread_state for SafeFetchInt()
257 volatile JavaThreadState _thread_state;
258 ThreadSafepointState* _safepoint_state; // Holds information about a thread during a safepoint
259 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened
260 NOT_PRODUCT(bool _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
261 #ifdef ASSERT
262 // Debug support for checking if code allows safepoints or not.
263 // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
264 // mutex, or blocking on an object synchronizer (Java locking).
265 // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
266 // the above cases. The class NoSafepointVerifier is used to set this counter.
267 int _no_safepoint_count; // If 0, thread allow a safepoint to happen
268
269 public:
270 void inc_no_safepoint_count() { _no_safepoint_count++; }
271 void dec_no_safepoint_count() { _no_safepoint_count--; }
272 bool is_in_no_safepoint_scope() { return _no_safepoint_count > 0; }
273 #endif // ASSERT
274 public:
275 // These functions check conditions before possibly going to a safepoint.
276 // including NoSafepointVerifier.
277 void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
278 void check_possible_safepoint() NOT_DEBUG_RETURN;
279
280 #ifdef ASSERT
281 private:
282 volatile uint64_t _visited_for_critical_count;
283
284 public:
285 void set_visited_for_critical_count(uint64_t safepoint_id) {
286 assert(_visited_for_critical_count == 0, "Must be reset before set");
287 assert((safepoint_id & 0x1) == 1, "Must be odd");
288 _visited_for_critical_count = safepoint_id;
289 }
290 void reset_visited_for_critical_count(uint64_t safepoint_id) {
291 assert(_visited_for_critical_count == safepoint_id, "Was not visited");
292 _visited_for_critical_count = 0;
293 }
294 bool was_visited_for_critical_count(uint64_t safepoint_id) const {
295 return _visited_for_critical_count == safepoint_id;
296 }
297 #endif // ASSERT
298
299 // JavaThread termination support
300 public:
301 enum TerminatedTypes {
302 _not_terminated = 0xDEAD - 3,
303 _thread_exiting, // JavaThread::exit() has been called for this thread
304 _thread_gc_barrier_detached, // thread's GC barrier has been detached
305 _thread_terminated, // JavaThread is removed from thread list
306 _vm_exited // JavaThread is still executing native code, but VM is terminated
307 // only VM_Exit can set _vm_exited
308 };
309
310 private:
311 // In general a JavaThread's _terminated field transitions as follows:
312 //
313 // _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
314 //
315 // _vm_exited is a special value to cover the case of a JavaThread
316 // executing native code after the VM itself is terminated.
317 //
318 // A JavaThread that fails to JNI attach has these _terminated field transitions:
319 // _not_terminated => _thread_terminated
320 //
321 volatile TerminatedTypes _terminated;
322
323 jint _in_deopt_handler; // count of deoptimization
324 // handlers thread is in
325 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access
326 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
327 // never locked) when throwing an exception. Used by interpreter only.
328 #if INCLUDE_JVMTI
329 volatile bool _carrier_thread_suspended; // Carrier thread is externally suspended
330 bool _is_in_VTMS_transition; // thread is in virtual thread mount state transition
331 bool _is_disable_suspend; // JVMTI suspend is temporarily disabled; used on current thread only
332 bool _is_in_java_upcall; // JVMTI is doing a Java upcall, so JVMTI events must be hidden
333 bool _VTMS_transition_mark; // used for sync between VTMS transitions and disablers
334 bool _on_monitor_waited_event; // Avoid callee arg processing for enterSpecial when posting waited event
335 ObjectMonitor* _contended_entered_monitor; // Monitor for pending monitor_contended_entered callback
336 #ifdef ASSERT
337 bool _is_VTMS_transition_disabler; // thread currently disabled VTMS transitions
338 #endif
339 #endif
340
341 // JNI attach states:
342 enum JNIAttachStates {
343 _not_attaching_via_jni = 1, // thread is not attaching via JNI
344 _attaching_via_jni, // thread is attaching via JNI
345 _attached_via_jni // thread has attached via JNI
346 };
347
348 // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
349 // A native thread that is attaching via JNI starts with a value
350 // of _attaching_via_jni and transitions to _attached_via_jni.
351 volatile JNIAttachStates _jni_attach_state;
352
353 // In scope of an InternalOOMEMark?
354 bool _is_in_internal_oome_mark;
355
356 #if INCLUDE_JVMCI
357 // The _pending_* fields below are used to communicate extra information
358 // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
359
360 // Communicates the DeoptReason and DeoptAction of the uncommon trap
361 int _pending_deoptimization;
362
363 // Specifies whether the uncommon trap is to bci 0 of a synchronized method
364 // before the monitor has been acquired.
365 bool _pending_monitorenter;
366
367 // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
368 bool _pending_transfer_to_interpreter;
369
370 // An id of a speculation that JVMCI compiled code can use to further describe and
371 // uniquely identify the speculative optimization guarded by an uncommon trap.
372 // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
373 jlong _pending_failed_speculation;
374
375 // These fields are mutually exclusive in terms of live ranges.
376 union {
377 // Communicates the pc at which the most recent implicit exception occurred
378 // from the signal handler to a deoptimization stub.
379 address _implicit_exception_pc;
380
381 // Communicates an alternative call target to an i2c stub from a JavaCall .
382 address _alternate_call_target;
383 } _jvmci;
384
385 // The JVMCIRuntime in a JVMCI shared library
386 JVMCIRuntime* _libjvmci_runtime;
387
388 // Support for high precision, thread sensitive counters in JVMCI compiled code.
389 jlong* _jvmci_counters;
390
391 // Fast thread locals for use by JVMCI
392 jlong _jvmci_reserved0;
393 jlong _jvmci_reserved1;
394 oop _jvmci_reserved_oop0;
395
396 // This field is used to keep an nmethod visible to the GC so that it and its contained oops can
397 // be kept alive
398 nmethod* _live_nmethod;
399
400 public:
401 static jlong* _jvmci_old_thread_counters;
402 static void collect_counters(jlong* array, int length);
403
404 bool resize_counters(int current_size, int new_size);
405
406 static bool resize_all_jvmci_counters(int new_size);
407
408 void set_jvmci_reserved_oop0(oop value) {
409 _jvmci_reserved_oop0 = value;
410 }
411
412 oop get_jvmci_reserved_oop0() {
413 return _jvmci_reserved_oop0;
414 }
415
416 void set_jvmci_reserved0(jlong value) {
417 _jvmci_reserved0 = value;
418 }
419
420 jlong get_jvmci_reserved0() {
421 return _jvmci_reserved0;
422 }
423
424 void set_jvmci_reserved1(jlong value) {
425 _jvmci_reserved1 = value;
426 }
427
428 jlong get_jvmci_reserved1() {
429 return _jvmci_reserved1;
430 }
431
432 void set_live_nmethod(nmethod* nm) {
433 assert(_live_nmethod == nullptr, "only one");
434 _live_nmethod = nm;
435 }
436
437 void clear_live_nmethod() {
438 _live_nmethod = nullptr;
439 }
440
441 private:
442 #endif // INCLUDE_JVMCI
443
444 StackOverflow _stack_overflow_state;
445
446 void pretouch_stack();
447
448 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
449 // used to temp. parsing values into and out of the runtime system during exception handling for compiled
450 // code)
451 volatile oop _exception_oop; // Exception thrown in compiled code
452 volatile address _exception_pc; // PC where exception happened
453 volatile address _exception_handler_pc; // PC for handler of exception
454 volatile int _is_method_handle_return; // true (== 1) if the current exception PC is a MethodHandle call site.
455
456 private:
457 // support for JNI critical regions
458 jint _jni_active_critical; // count of entries into JNI critical region
459
460 // Checked JNI: function name requires exception check
461 char* _pending_jni_exception_check_fn;
462
463 // For deadlock detection.
464 int _depth_first_number;
465
466 // JVMTI PopFrame support
467 // This is set to popframe_pending to signal that top Java frame should be popped immediately
468 int _popframe_condition;
469
470 // If reallocation of scalar replaced objects fails, we throw OOM
471 // and during exception propagation, pop the top
472 // _frames_to_pop_failed_realloc frames, the ones that reference
473 // failed reallocations.
474 int _frames_to_pop_failed_realloc;
475
476 ContinuationEntry* _cont_entry;
477 intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub/upcall_stub/native_wrapper
478 // frame inside the continuation that we know about
479 int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
480
481 // It's signed for error detection.
482 intx _held_monitor_count; // used by continuations for fast lock detection
483 intx _jni_monitor_count;
484 ObjectMonitor* _unlocked_inflated_monitor;
485
486 // This is the field we poke in the interpreter and native
487 // wrapper (Object.wait) to check for preemption.
488 address _preempt_alternate_return;
489 // When preempting on monitorenter we could have acquired the
490 // monitor after freezing all vthread frames. In that case we
491 // set this field so that in the preempt stub we call thaw again
492 // instead of unmounting.
493 bool _preemption_cancelled;
494 // For Object.wait() we set this field to know if we need to
495 // throw IE at the end of thawing before returning to Java.
496 bool _pending_interrupted_exception;
497
498 public:
499 bool preemption_cancelled() { return _preemption_cancelled; }
500 void set_preemption_cancelled(bool b) { _preemption_cancelled = b; }
501
502 bool pending_interrupted_exception() { return _pending_interrupted_exception; }
503 void set_pending_interrupted_exception(bool b) { _pending_interrupted_exception = b; }
504
505 bool preempting() { return _preempt_alternate_return != nullptr; }
506 void set_preempt_alternate_return(address val) { _preempt_alternate_return = val; }
507
508 private:
509
510 friend class VMThread;
511 friend class ThreadWaitTransition;
512 friend class VM_Exit;
513
514 // Stack watermark barriers.
515 StackWatermarks _stack_watermarks;
516
517 public:
518 inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
519
520 public:
521 // Constructor
522 JavaThread(MemTag mem_tag = mtThread); // delegating constructor
523 JavaThread(ThreadFunction entry_point, size_t stack_size = 0, MemTag mem_tag = mtThread);
524 ~JavaThread();
525
526 // Factory method to create a new JavaThread whose attach state is "is attaching"
527 static JavaThread* create_attaching_thread();
528
529 #ifdef ASSERT
530 // verify this JavaThread hasn't be published in the Threads::list yet
531 void verify_not_published();
532 #endif // ASSERT
533
534 StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
535
536 //JNI functiontable getter/setter for JVMTI jni function table interception API.
537 void set_jni_functions(struct JNINativeInterface_* functionTable) {
538 _jni_environment.functions = functionTable;
539 }
540 struct JNINativeInterface_* get_jni_functions() {
541 return (struct JNINativeInterface_ *)_jni_environment.functions;
542 }
543
544 // This function is called at thread creation to allow
545 // platform specific thread variables to be initialized.
546 void cache_global_variables();
547
548 // Executes Shutdown.shutdown()
549 void invoke_shutdown_hooks();
550
551 // Cleanup on thread exit
552 enum ExitType {
553 normal_exit,
554 jni_detach
555 };
556 void exit(bool destroy_vm, ExitType exit_type = normal_exit);
557
558 void cleanup_failed_attach_current_thread(bool is_daemon);
559
560 // Testers
561 virtual bool is_Java_thread() const { return true; }
562 virtual bool can_call_java() const { return true; }
563
564 virtual bool is_active_Java_thread() const;
565
566 // Thread oop. threadObj() can be null for initial JavaThread
567 // (or for threads attached via JNI)
568 oop threadObj() const;
569 void set_threadOopHandles(oop p);
570 oop vthread() const;
571 void set_vthread(oop p);
572 oop scopedValueCache() const;
573 void set_scopedValueCache(oop p);
574 void clear_scopedValueBindings();
575 oop jvmti_vthread() const;
576 void set_jvmti_vthread(oop p);
577 oop vthread_or_thread() const;
578
579 // Prepare thread and add to priority queue. If a priority is
580 // not specified, use the priority of the thread object. Threads_lock
581 // must be held while this function is called.
582 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
583
584 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; }
585 address saved_exception_pc() { return _saved_exception_pc; }
586
587 ThreadFunction entry_point() const { return _entry_point; }
588
589 // Allocates a new Java level thread object for this thread. thread_name may be null.
590 void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
591
592 // Last frame anchor routines
593
594 JavaFrameAnchor* frame_anchor(void) { return &_anchor; }
595
596 // last_Java_sp
597 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); }
598 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); }
599
600 // last_Java_pc
601
602 address last_Java_pc(void) { return _anchor.last_Java_pc(); }
603
604 // Safepoint support
605 inline JavaThreadState thread_state() const;
606 inline void set_thread_state(JavaThreadState s);
607 inline void set_thread_state_fence(JavaThreadState s); // fence after setting thread state
608 inline ThreadSafepointState* safepoint_state() const;
609 inline void set_safepoint_state(ThreadSafepointState* state);
610 inline bool is_at_poll_safepoint();
611
612 // JavaThread termination and lifecycle support:
613 void smr_delete();
614 bool on_thread_list() const { return _on_thread_list; }
615 void set_on_thread_list() { _on_thread_list = true; }
616
617 // thread has called JavaThread::exit(), thread's GC barrier is detached
618 // or thread is terminated
619 bool is_exiting() const;
620 // thread's GC barrier is NOT detached and thread is NOT terminated
621 bool is_oop_safe() const;
622 // thread is terminated (no longer on the threads list); the thread must
623 // be protected by a ThreadsListHandle to avoid potential crashes.
624 bool check_is_terminated(TerminatedTypes l_terminated) const {
625 return l_terminated == _thread_terminated || l_terminated == _vm_exited;
626 }
627 bool is_terminated() const;
628 void set_terminated(TerminatedTypes t);
629
630 void block_if_vm_exited();
631
632 bool doing_unsafe_access() { return _doing_unsafe_access; }
633 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; }
634
635 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; }
636 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
637
638 SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
639
640 static ByteSize polling_word_offset() {
641 ByteSize offset = byte_offset_of(Thread, _poll_data) +
642 byte_offset_of(SafepointMechanism::ThreadData, _polling_word);
643 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
644 assert(in_bytes(offset) < 128, "Offset >= 128");
645 return offset;
646 }
647
648 static ByteSize polling_page_offset() {
649 ByteSize offset = byte_offset_of(Thread, _poll_data) +
650 byte_offset_of(SafepointMechanism::ThreadData, _polling_page);
651 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
652 assert(in_bytes(offset) < 128, "Offset >= 128");
653 return offset;
654 }
655
656 void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
657
658 // Continuation support
659 ContinuationEntry* last_continuation() const { return _cont_entry; }
660 void set_cont_fastpath(intptr_t* x) { _cont_fastpath = x; }
661 void push_cont_fastpath(intptr_t* sp) { if (sp > _cont_fastpath) _cont_fastpath = sp; }
662 void set_cont_fastpath_thread_state(bool x) { _cont_fastpath_thread_state = (int)x; }
663 intptr_t* raw_cont_fastpath() const { return _cont_fastpath; }
664 bool cont_fastpath() const { return _cont_fastpath == nullptr && _cont_fastpath_thread_state != 0; }
665 bool cont_fastpath_thread_state() const { return _cont_fastpath_thread_state != 0; }
666
667 void inc_held_monitor_count(intx i = 1, bool jni = false);
668 void dec_held_monitor_count(intx i = 1, bool jni = false);
669
670 intx held_monitor_count() { return _held_monitor_count; }
671 intx jni_monitor_count() { return _jni_monitor_count; }
672 void clear_jni_monitor_count() { _jni_monitor_count = 0; }
673
674 // Support for SharedRuntime::monitor_exit_helper()
675 ObjectMonitor* unlocked_inflated_monitor() const { return _unlocked_inflated_monitor; }
676 void clear_unlocked_inflated_monitor() {
677 _unlocked_inflated_monitor = nullptr;
678 }
679
680 inline bool is_vthread_mounted() const;
681 inline const ContinuationEntry* vthread_continuation() const;
682
683 private:
684 DEBUG_ONLY(void verify_frame_info();)
685
686 // Support for thread handshake operations
687 HandshakeState _handshake;
688 public:
689 HandshakeState* handshake_state() { return &_handshake; }
690
691 // A JavaThread can always safely operate on it self and other threads
692 // can do it safely if they are the active handshaker.
693 bool is_handshake_safe_for(Thread* th) const {
694 return _handshake.active_handshaker() == th || this == th;
695 }
696
697 // Suspend/resume support for JavaThread
698 // higher-level suspension/resume logic called by the public APIs
699 private:
700 SuspendResumeManager _suspend_resume_manager;
701 public:
702 bool java_suspend(bool register_vthread_SR);
703 bool java_resume(bool register_vthread_SR);
704 bool is_suspended() { return _suspend_resume_manager.is_suspended(); }
705 SuspendResumeManager* suspend_resume_manager() { return &_suspend_resume_manager; }
706
707 // Check for async exception in addition to safepoint.
708 static void check_special_condition_for_native_trans(JavaThread *thread);
709
710 // Synchronize with another thread that is deoptimizing objects of the
711 // current thread, i.e. reverts optimizations based on escape analysis.
712 void wait_for_object_deoptimization();
713
714 #if INCLUDE_JVMTI
715 inline bool set_carrier_thread_suspended();
716 inline bool clear_carrier_thread_suspended();
717
718 bool is_carrier_thread_suspended() const {
719 return Atomic::load(&_carrier_thread_suspended);
720 }
721
722 bool is_in_VTMS_transition() const { return _is_in_VTMS_transition; }
723 void set_is_in_VTMS_transition(bool val);
724
725 bool is_disable_suspend() const { return _is_disable_suspend; }
726 void toggle_is_disable_suspend() { _is_disable_suspend = !_is_disable_suspend; };
727
728 bool is_in_java_upcall() const { return _is_in_java_upcall; }
729 void toggle_is_in_java_upcall() { _is_in_java_upcall = !_is_in_java_upcall; };
730
731 bool VTMS_transition_mark() const { return Atomic::load(&_VTMS_transition_mark); }
732 void set_VTMS_transition_mark(bool val) { Atomic::store(&_VTMS_transition_mark, val); }
733
734 // Temporarily skip posting JVMTI events for safety reasons when executions is in a critical section:
735 // - is in a VTMS transition (_is_in_VTMS_transition)
736 // - is in an interruptLock or similar critical section (_is_disable_suspend)
737 // - JVMTI is making a Java upcall (_is_in_java_upcall)
738 bool should_hide_jvmti_events() const { return _is_in_VTMS_transition || _is_disable_suspend || _is_in_java_upcall; }
739
740 bool on_monitor_waited_event() { return _on_monitor_waited_event; }
741 void set_on_monitor_waited_event(bool val) { _on_monitor_waited_event = val; }
742
743 bool pending_contended_entered_event() { return _contended_entered_monitor != nullptr; }
744 ObjectMonitor* contended_entered_monitor() { return _contended_entered_monitor; }
745 #ifdef ASSERT
746 bool is_VTMS_transition_disabler() const { return _is_VTMS_transition_disabler; }
747 void set_is_VTMS_transition_disabler(bool val);
748 #endif
749 #endif
750
751 void set_contended_entered_monitor(ObjectMonitor* val) NOT_JVMTI_RETURN JVMTI_ONLY({ _contended_entered_monitor = val; })
752
753 // Support for object deoptimization and JFR suspension
754 void handle_special_runtime_exit_condition();
755 bool has_special_runtime_exit_condition() {
756 return (_suspend_flags & _obj_deopt) != 0;
757 }
758
759 // Stack-locking support (not for LM_LIGHTWEIGHT)
760 bool is_lock_owned(address adr) const;
761
762 // Accessors for vframe array top
763 // The linked list of vframe arrays are sorted on sp. This means when we
764 // unpack the head must contain the vframe array to unpack.
765 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
766 vframeArray* vframe_array_head() const { return _vframe_array_head; }
767
768 // Side structure for deferring update of java frame locals until deopt occurs
769 JvmtiDeferredUpdates* deferred_updates() const { return _jvmti_deferred_updates; }
770 void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
771
772 // These only really exist to make debugging deopt problems simpler
773
774 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
775 vframeArray* vframe_array_last() const { return _vframe_array_last; }
776
777 // The special resourceMark used during deoptimization
778
779 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; }
780 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; }
781
782 void set_deopt_compiled_method(nmethod* nm) { _deopt_nmethod = nm; }
783 nmethod* deopt_compiled_method() { return _deopt_nmethod; }
784
785 Method* callee_target() const { return _callee_target; }
786 void set_callee_target (Method* x) { _callee_target = x; }
787
788 // Oop results of vm runtime calls
789 oop vm_result_oop() const { return _vm_result_oop; }
790 void set_vm_result_oop(oop x) { _vm_result_oop = x; }
791
792 void set_vm_result_metadata(Metadata* x) { _vm_result_metadata = x; }
793
794 oop return_buffered_value() const { return _return_buffered_value; }
795 void set_return_buffered_value(oop val) { _return_buffered_value = val; }
796
797 MemRegion deferred_card_mark() const { return _deferred_card_mark; }
798 void set_deferred_card_mark(MemRegion mr) { _deferred_card_mark = mr; }
799
800 // Is thread in scope of an InternalOOMEMark?
801 bool is_in_internal_oome_mark() const { return _is_in_internal_oome_mark; }
802 void set_is_in_internal_oome_mark(bool b) { _is_in_internal_oome_mark = b; }
803
804 #if INCLUDE_JVMCI
805 jlong pending_failed_speculation() const { return _pending_failed_speculation; }
806 void set_pending_monitorenter(bool b) { _pending_monitorenter = b; }
807 void set_pending_deoptimization(int reason) { _pending_deoptimization = reason; }
808 void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
809 void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
810 void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == nullptr, "must be"); _jvmci._alternate_call_target = a; }
811 void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == nullptr, "must be"); _jvmci._implicit_exception_pc = a; }
812
813 JVMCIRuntime* libjvmci_runtime() const { return _libjvmci_runtime; }
814 void set_libjvmci_runtime(JVMCIRuntime* rt) {
815 assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
816 _libjvmci_runtime = rt;
817 }
818 #endif // INCLUDE_JVMCI
819
820 // Exception handling for compiled methods
821 oop exception_oop() const;
822 address exception_pc() const { return _exception_pc; }
823
824 void set_exception_oop(oop o);
825 void set_exception_pc(address a) { _exception_pc = a; }
826 void set_exception_handler_pc(address a) { _exception_handler_pc = a; }
827 void set_is_method_handle_return(bool value) { _is_method_handle_return = value ? 1 : 0; }
828
829 void clear_exception_oop_and_pc() {
830 set_exception_oop(nullptr);
831 set_exception_pc(nullptr);
832 }
833
834 // Check if address is in the usable part of the stack (excludes protected
835 // guard pages). Can be applied to any thread and is an approximation for
836 // using is_in_live_stack when the query has to happen from another thread.
837 bool is_in_usable_stack(address adr) const {
838 return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
839 }
840
841 // Misc. accessors/mutators
842 static ByteSize scopedValueCache_offset() { return byte_offset_of(JavaThread, _scopedValueCache); }
843
844 // For assembly stub generation
845 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj); }
846 static ByteSize vthread_offset() { return byte_offset_of(JavaThread, _vthread); }
847 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment); }
848 static ByteSize pending_jni_exception_check_fn_offset() {
849 return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
850 }
851 static ByteSize last_Java_sp_offset() {
852 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
853 }
854 static ByteSize last_Java_pc_offset() {
855 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
856 }
857 static ByteSize frame_anchor_offset() {
858 return byte_offset_of(JavaThread, _anchor);
859 }
860 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target); }
861 static ByteSize vm_result_oop_offset() { return byte_offset_of(JavaThread, _vm_result_oop); }
862 static ByteSize vm_result_metadata_offset() { return byte_offset_of(JavaThread, _vm_result_metadata); }
863 static ByteSize return_buffered_value_offset() { return byte_offset_of(JavaThread, _return_buffered_value); }
864 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state); }
865 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc); }
866 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread); }
867 #if INCLUDE_JVMCI
868 static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
869 static ByteSize pending_monitorenter_offset() { return byte_offset_of(JavaThread, _pending_monitorenter); }
870 static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
871 static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
872 static ByteSize jvmci_counters_offset() { return byte_offset_of(JavaThread, _jvmci_counters); }
873 #endif // INCLUDE_JVMCI
874 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop); }
875 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc); }
876 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); }
877 static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
878
879 static ByteSize active_handles_offset() { return byte_offset_of(JavaThread, _active_handles); }
880
881 // StackOverflow offsets
882 static ByteSize stack_overflow_limit_offset() {
883 return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
884 }
885 static ByteSize stack_guard_state_offset() {
886 return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
887 }
888 static ByteSize reserved_stack_activation_offset() {
889 return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
890 }
891 static ByteSize shadow_zone_safe_limit() {
892 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
893 }
894 static ByteSize shadow_zone_growth_watermark() {
895 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
896 }
897
898 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags); }
899
900 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
901 static ByteSize should_post_on_exceptions_flag_offset() {
902 return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
903 }
904 static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
905 NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset() { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
906
907 static ByteSize monitor_owner_id_offset() { return byte_offset_of(JavaThread, _monitor_owner_id); }
908
909 static ByteSize cont_entry_offset() { return byte_offset_of(JavaThread, _cont_entry); }
910 static ByteSize cont_fastpath_offset() { return byte_offset_of(JavaThread, _cont_fastpath); }
911 static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
912 static ByteSize jni_monitor_count_offset() { return byte_offset_of(JavaThread, _jni_monitor_count); }
913 static ByteSize preemption_cancelled_offset() { return byte_offset_of(JavaThread, _preemption_cancelled); }
914 static ByteSize preempt_alternate_return_offset() { return byte_offset_of(JavaThread, _preempt_alternate_return); }
915 static ByteSize unlocked_inflated_monitor_offset() { return byte_offset_of(JavaThread, _unlocked_inflated_monitor); }
916
917 #if INCLUDE_JVMTI
918 static ByteSize is_in_VTMS_transition_offset() { return byte_offset_of(JavaThread, _is_in_VTMS_transition); }
919 static ByteSize is_disable_suspend_offset() { return byte_offset_of(JavaThread, _is_disable_suspend); }
920 #endif
921
922 // Returns the jni environment for this thread
923 JNIEnv* jni_environment() { return &_jni_environment; }
924
925 // Returns the current thread as indicated by the given JNIEnv.
926 // We don't assert it is Thread::current here as that is done at the
927 // external JNI entry points where the JNIEnv is passed into the VM.
928 static JavaThread* thread_from_jni_environment(JNIEnv* env) {
929 JavaThread* current = reinterpret_cast<JavaThread*>(((intptr_t)env - in_bytes(jni_environment_offset())));
930 // We can't normally get here in a thread that has completed its
931 // execution and so "is_terminated", except when the call is from
932 // AsyncGetCallTrace, which can be triggered by a signal at any point in
933 // a thread's lifecycle. A thread is also considered terminated if the VM
934 // has exited, so we have to check this and block in case this is a daemon
935 // thread returning to the VM (the JNI DirectBuffer entry points rely on
936 // this).
937 if (current->is_terminated()) {
938 current->block_if_vm_exited();
939 }
940 return current;
941 }
942
943 // JNI critical regions. These can nest.
944 bool in_critical() { return _jni_active_critical > 0; }
945 bool in_last_critical() { return _jni_active_critical == 1; }
946 inline void enter_critical();
947 void exit_critical() {
948 assert(Thread::current() == this, "this must be current thread");
949 _jni_active_critical--;
950 assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
951 }
952
953 // Atomic version; invoked by a thread other than the owning thread.
954 bool in_critical_atomic() { return Atomic::load(&_jni_active_critical) > 0; }
955
956 // Checked JNI: is the programmer required to check for exceptions, if so specify
957 // which function name. Returning to a Java frame should implicitly clear the
958 // pending check, this is done for Native->Java transitions (i.e. user JNI code).
959 // VM->Java transitions are not cleared, it is expected that JNI code enclosed
960 // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
961 bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != nullptr; }
962 void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = nullptr; }
963 const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
964 void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
965
966 // For deadlock detection
967 int depth_first_number() { return _depth_first_number; }
968 void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
969
970 public:
971 bool in_deopt_handler() const { return _in_deopt_handler > 0; }
972 void inc_in_deopt_handler() { _in_deopt_handler++; }
973 void dec_in_deopt_handler() {
974 assert(_in_deopt_handler > 0, "mismatched deopt nesting");
975 if (_in_deopt_handler > 0) { // robustness
976 _in_deopt_handler--;
977 }
978 }
979
980 private:
981 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
982
983 // factor out low-level mechanics for use in both normal and error cases
984 const char* get_thread_name_string(char* buf = nullptr, int buflen = 0) const;
985
986 public:
987
988 // Frame iteration; calls the function f for all frames on the stack
989 void frames_do(void f(frame*, const RegisterMap*));
990
991 // Memory operations
992 void oops_do_frames(OopClosure* f, NMethodClosure* cf);
993 void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
994
995 // GC operations
996 virtual void nmethods_do(NMethodClosure* cf);
997
998 // RedefineClasses Support
999 void metadata_do(MetadataClosure* f);
1000
1001 // Debug method asserting thread states are correct during a handshake operation.
1002 DEBUG_ONLY(void verify_states_for_handshake();)
1003
1004 // Misc. operations
1005 const char* name() const;
1006 const char* name_raw() const;
1007 const char* type_name() const { return "JavaThread"; }
1008 static const char* name_for(oop thread_obj);
1009
1010 void print_on(outputStream* st, bool print_extended_info) const;
1011 void print_on(outputStream* st) const { print_on(st, false); }
1012 void print() const;
1013 void print_thread_state_on(outputStream*) const;
1014 void print_on_error(outputStream* st, char* buf, int buflen) const;
1015 void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1016 void verify();
1017
1018 // Accessing frames
1019 frame last_frame() {
1020 _anchor.make_walkable();
1021 return pd_last_frame();
1022 }
1023 javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
1024
1025 frame carrier_last_frame(RegisterMap* reg_map);
1026 javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
1027
1028 frame vthread_last_frame();
1029 javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
1030
1031 frame platform_thread_last_frame(RegisterMap* reg_map);
1032 javaVFrame* platform_thread_last_java_vframe(RegisterMap* reg_map) {
1033 return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
1034 }
1035
1036 javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
1037
1038 // Returns method at 'depth' java or native frames down the stack
1039 // Used for security checks
1040 Klass* security_get_caller_class(int depth);
1041
1042 // Print stack trace in external format
1043 // These variants print carrier/platform thread information only.
1044 void print_stack_on(outputStream* st);
1045 void print_stack() { print_stack_on(tty); }
1046 // This prints the currently mounted virtual thread.
1047 void print_vthread_stack_on(outputStream* st);
1048 // This prints the active stack: either carrier/platform or virtual.
1049 void print_active_stack_on(outputStream* st);
1050 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1051 // This is the external format from above, but selecting the platform
1052 // or vthread as applicable.
1053 void print_jni_stack();
1054
1055 // Print stack traces in various internal formats
1056 void trace_stack() PRODUCT_RETURN;
1057 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN;
1058 void trace_frames() PRODUCT_RETURN;
1059
1060 // Print an annotated view of the stack frames
1061 void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1062 void validate_frame_layout() {
1063 print_frame_layout(0, true);
1064 }
1065
1066 // Function for testing deoptimization
1067 void deoptimize();
1068 void make_zombies();
1069
1070 void deoptimize_marked_methods();
1071
1072 public:
1073 // Returns the running thread as a JavaThread
1074 static JavaThread* current() {
1075 return JavaThread::cast(Thread::current());
1076 }
1077
1078 // Returns the current thread as a JavaThread, or nullptr if not attached
1079 static inline JavaThread* current_or_null();
1080
1081 // Casts
1082 static JavaThread* cast(Thread* t) {
1083 assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1084 return static_cast<JavaThread*>(t);
1085 }
1086
1087 static const JavaThread* cast(const Thread* t) {
1088 assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1089 return static_cast<const JavaThread*>(t);
1090 }
1091
1092 // Returns the active Java thread. Do not use this if you know you are calling
1093 // from a JavaThread, as it's slower than JavaThread::current. If called from
1094 // the VMThread, it also returns the JavaThread that instigated the VMThread's
1095 // operation. You may not want that either.
1096 static JavaThread* active();
1097
1098 protected:
1099 virtual void pre_run();
1100 virtual void run();
1101 void thread_main_inner();
1102 virtual void post_run();
1103
1104 public:
1105 // Thread local information maintained by JVMTI.
1106 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; }
1107 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1108 // getter is used to get this JavaThread's JvmtiThreadState if it has
1109 // one which means null can be returned. JvmtiThreadState::state_for()
1110 // is used to get the specified JavaThread's JvmtiThreadState if it has
1111 // one or it allocates a new JvmtiThreadState for the JavaThread and
1112 // returns it. JvmtiThreadState::state_for() will return null only if
1113 // the specified JavaThread is exiting.
1114 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; }
1115 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1116
1117 #if INCLUDE_JVMTI
1118 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1119 JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1120 #endif
1121
1122 // JVMTI PopFrame support
1123 // Setting and clearing popframe_condition
1124 // All of these enumerated values are bits. popframe_pending
1125 // indicates that a PopFrame() has been requested and not yet been
1126 // completed. popframe_processing indicates that that PopFrame() is in
1127 // the process of being completed. popframe_force_deopt_reexecution_bit
1128 // indicates that special handling is required when returning to a
1129 // deoptimized caller.
1130 enum PopCondition {
1131 popframe_inactive = 0x00,
1132 popframe_pending_bit = 0x01,
1133 popframe_processing_bit = 0x02,
1134 popframe_force_deopt_reexecution_bit = 0x04
1135 };
1136 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; }
1137 void set_popframe_condition(PopCondition c) { _popframe_condition = c; }
1138 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; }
1139 void clear_popframe_condition() { _popframe_condition = popframe_inactive; }
1140 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); }
1141 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; }
1142 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1143
1144 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); }
1145 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; }
1146 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; }
1147
1148 int frames_to_pop_failed_realloc() const { return _frames_to_pop_failed_realloc; }
1149 void set_frames_to_pop_failed_realloc(int nb) { _frames_to_pop_failed_realloc = nb; }
1150 void dec_frames_to_pop_failed_realloc() { _frames_to_pop_failed_realloc--; }
1151
1152 private:
1153 // Saved incoming arguments to popped frame.
1154 // Used only when popped interpreted frame returns to deoptimized frame.
1155 void* _popframe_preserved_args;
1156 int _popframe_preserved_args_size;
1157
1158 public:
1159 void popframe_preserve_args(ByteSize size_in_bytes, void* start);
1160 void* popframe_preserved_args();
1161 ByteSize popframe_preserved_args_size();
1162 WordSize popframe_preserved_args_size_in_words();
1163 void popframe_free_preserved_args();
1164
1165
1166 private:
1167 JvmtiThreadState *_jvmti_thread_state;
1168
1169 // Used by the interpreter in fullspeed mode for frame pop, method
1170 // entry, method exit and single stepping support. This field is
1171 // only set to non-zero at a safepoint or using a direct handshake
1172 // (see EnterInterpOnlyModeHandshakeClosure).
1173 // It can be set to zero asynchronously to this threads execution (i.e., without
1174 // safepoint/handshake or a lock) so we have to be very careful.
1175 // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1176 // This field is checked by the interpreter which expects it to be an integer.
1177 int _interp_only_mode;
1178
1179 public:
1180 // used by the interpreter for fullspeed debugging support (see above)
1181 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1182 bool is_interp_only_mode() { return (_interp_only_mode != 0); }
1183 void set_interp_only_mode(bool val) { _interp_only_mode = val ? 1 : 0; }
1184
1185 // support for cached flag that indicates whether exceptions need to be posted for this thread
1186 // if this is false, we can avoid deoptimizing when events are thrown
1187 // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1188 private:
1189 int _should_post_on_exceptions_flag;
1190
1191 public:
1192 void set_should_post_on_exceptions_flag(int val) { _should_post_on_exceptions_flag = val; }
1193
1194 private:
1195 ThreadStatistics *_thread_stat;
1196
1197 public:
1198 ThreadStatistics* get_thread_stat() const { return _thread_stat; }
1199
1200 // Return a blocker object for which this thread is blocked parking.
1201 oop current_park_blocker();
1202
1203 private:
1204 static size_t _stack_size_at_create;
1205
1206 public:
1207 static inline size_t stack_size_at_create(void) {
1208 return _stack_size_at_create;
1209 }
1210 static inline void set_stack_size_at_create(size_t value) {
1211 _stack_size_at_create = value;
1212 }
1213
1214 // Machine dependent stuff
1215 #include OS_CPU_HEADER(javaThread)
1216
1217 // JSR166 per-thread parker
1218 private:
1219 Parker _parker;
1220 public:
1221 Parker* parker() { return &_parker; }
1222
1223 public:
1224 // clearing/querying jni attach status
1225 bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1226 bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1227 inline void set_done_attaching_via_jni();
1228
1229 // Stack dump assistance:
1230 // Track the class we want to initialize but for which we have to wait
1231 // on its init_lock() because it is already being initialized.
1232 void set_class_to_be_initialized(InstanceKlass* k);
1233 InstanceKlass* class_to_be_initialized() const;
1234
1235 // Track executing class initializer, see ThreadInClassInitializer
1236 void set_class_being_initialized(InstanceKlass* k);
1237 InstanceKlass* class_being_initialized() const;
1238
1239 private:
1240 InstanceKlass* _class_to_be_initialized;
1241 InstanceKlass* _class_being_initialized;
1242
1243 // java.lang.Thread.sleep support
1244 ParkEvent * _SleepEvent;
1245
1246 #if INCLUDE_JFR
1247 // Support for jdk.VirtualThreadPinned event
1248 freeze_result _last_freeze_fail_result;
1249 Ticks _last_freeze_fail_time;
1250 #endif
1251
1252 public:
1253 bool sleep(jlong millis);
1254 bool sleep_nanos(jlong nanos);
1255
1256 // java.lang.Thread interruption support
1257 void interrupt();
1258 bool is_interrupted(bool clear_interrupted);
1259
1260 #if INCLUDE_JFR
1261 // Support for jdk.VirtualThreadPinned event
1262 freeze_result last_freeze_fail_result() { return _last_freeze_fail_result; }
1263 Ticks& last_freeze_fail_time() { return _last_freeze_fail_time; }
1264 void set_last_freeze_fail_result(freeze_result result);
1265 #endif
1266 void post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) NOT_JFR_RETURN();
1267
1268
1269 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
1270 // the Java code in Object::wait which are not present in RawMonitorWait.
1271 bool get_and_clear_interrupted();
1272
1273 private:
1274 LockStack _lock_stack;
1275 OMCache _om_cache;
1276
1277 public:
1278 LockStack& lock_stack() { return _lock_stack; }
1279
1280 static ByteSize lock_stack_offset() { return byte_offset_of(JavaThread, _lock_stack); }
1281 // Those offsets are used in code generators to access the LockStack that is embedded in this
1282 // JavaThread structure. Those accesses are relative to the current thread, which
1283 // is typically in a dedicated register.
1284 static ByteSize lock_stack_top_offset() { return lock_stack_offset() + LockStack::top_offset(); }
1285 static ByteSize lock_stack_base_offset() { return lock_stack_offset() + LockStack::base_offset(); }
1286
1287 static ByteSize om_cache_offset() { return byte_offset_of(JavaThread, _om_cache); }
1288 static ByteSize om_cache_oops_offset() { return om_cache_offset() + OMCache::entries_offset(); }
1289
1290 void om_set_monitor_cache(ObjectMonitor* monitor);
1291 void om_clear_monitor_cache();
1292 ObjectMonitor* om_get_from_monitor_cache(oop obj);
1293
1294 static OopStorage* thread_oop_storage();
1295
1296 static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1297
1298 // Helper function to create the java.lang.Thread object for a
1299 // VM-internal thread. The thread will have the given name and be
1300 // part of the System ThreadGroup.
1301 static Handle create_system_thread_object(const char* name, TRAPS);
1302
1303 // Helper function to start a VM-internal daemon thread.
1304 // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1305 static void start_internal_daemon(JavaThread* current, JavaThread* target,
1306 Handle thread_oop, ThreadPriority prio);
1307
1308 // Helper function to do vm_exit_on_initialization for osthread
1309 // resource allocation failure.
1310 static void vm_exit_on_osthread_failure(JavaThread* thread);
1311
1312 // Deferred OopHandle release support
1313 private:
1314 // List of OopHandles to be released - guarded by the Service_lock.
1315 static OopHandleList* _oop_handle_list;
1316 // Add our OopHandles to the list for the service thread to release.
1317 void add_oop_handles_for_release();
1318 // Called by the ServiceThread to release the OopHandles.
1319 static void release_oop_handles();
1320 // Called by the ServiceThread to poll if there are any OopHandles to release.
1321 // Called when holding the Service_lock.
1322 static bool has_oop_handles_to_release() {
1323 return _oop_handle_list != nullptr;
1324 }
1325 };
1326
1327 inline JavaThread* JavaThread::current_or_null() {
1328 Thread* current = Thread::current_or_null();
1329 return current != nullptr ? JavaThread::cast(current) : nullptr;
1330 }
1331
1332 class UnlockFlagSaver {
1333 private:
1334 JavaThread* _thread;
1335 bool _do_not_unlock;
1336 public:
1337 UnlockFlagSaver(JavaThread* t) {
1338 _thread = t;
1339 _do_not_unlock = t->do_not_unlock_if_synchronized();
1340 t->set_do_not_unlock_if_synchronized(false);
1341 }
1342 ~UnlockFlagSaver() {
1343 _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1344 }
1345 };
1346
1347 class JNIHandleMark : public StackObj {
1348 JavaThread* _thread;
1349 public:
1350 JNIHandleMark(JavaThread* thread) : _thread(thread) {
1351 thread->push_jni_handle_block();
1352 }
1353 ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1354 };
1355
1356 class NoPreemptMark {
1357 ContinuationEntry* _ce;
1358 bool _unpin;
1359 public:
1360 NoPreemptMark(JavaThread* thread) : _ce(thread->last_continuation()), _unpin(false) {
1361 if (_ce != nullptr) _unpin = _ce->pin();
1362 }
1363 ~NoPreemptMark() { if (_unpin) _ce->unpin(); }
1364 };
1365
1366 class ThreadOnMonitorWaitedEvent {
1367 JavaThread* _thread;
1368 public:
1369 ThreadOnMonitorWaitedEvent(JavaThread* thread) : _thread(thread) {
1370 JVMTI_ONLY(_thread->set_on_monitor_waited_event(true);)
1371 }
1372 ~ThreadOnMonitorWaitedEvent() { JVMTI_ONLY(_thread->set_on_monitor_waited_event(false);) }
1373 };
1374
1375 class ThreadInClassInitializer : public StackObj {
1376 JavaThread* _thread;
1377 InstanceKlass* _previous;
1378 public:
1379 ThreadInClassInitializer(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1380 _previous = _thread->class_being_initialized();
1381 _thread->set_class_being_initialized(ik);
1382 }
1383 ~ThreadInClassInitializer() {
1384 _thread->set_class_being_initialized(_previous);
1385 }
1386 };
1387
1388 #endif // SHARE_RUNTIME_JAVATHREAD_HPP