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