1 /*
2 * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #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/thread.hpp"
44 #include "runtime/threadHeapSampler.hpp"
45 #include "runtime/threadIdentifier.hpp"
46 #include "runtime/threadStatisticalInfo.hpp"
47 #include "utilities/exceptions.hpp"
48 #include "utilities/globalDefinitions.hpp"
49 #include "utilities/macros.hpp"
50 #if INCLUDE_JFR
51 #include "jfr/support/jfrThreadExtension.hpp"
52 #include "utilities/ticks.hpp"
53 #endif
54
55 class AsyncExceptionHandshake;
56 class DeoptResourceMark;
57 class InternalOOMEMark;
58 class JNIHandleBlock;
59 class JVMCIRuntime;
60
61 class JvmtiDeferredUpdates;
62 class JvmtiSampledObjectAllocEventCollector;
63 class JvmtiThreadState;
64
65 class Metadata;
66 class ObjectMonitor;
67 class OopHandleList;
68 class OopStorage;
69 class OSThread;
70
71 class ThreadsList;
72 class ThreadSafepointState;
73 class ThreadStatistics;
74
75 class vframeArray;
76 class vframe;
77 class javaVFrame;
78
79 class JavaThread;
80 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
81
82 class EventVirtualThreadPinned;
83
84 class JavaThread: public Thread {
85 friend class VMStructs;
86 friend class JVMCIVMStructs;
87 friend class WhiteBox;
88 friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
89 friend class HandshakeState;
90 friend class Continuation;
91 friend class Threads;
92 friend class ServiceThread; // for deferred OopHandle release access
93 private:
94 bool _on_thread_list; // Is set when this JavaThread is added to the Threads list
95
96 // All references to Java objects managed via OopHandles. These
97 // have to be released by the ServiceThread after the JavaThread has
98 // terminated - see add_oop_handles_for_release().
99 OopHandle _threadObj; // The Java level thread object
100 OopHandle _vthread; // the value returned by Thread.currentThread(): the virtual thread, if mounted, otherwise _threadObj
101 OopHandle _jvmti_vthread;
102 OopHandle _scopedValueCache;
103
104 static OopStorage* _thread_oop_storage;
105
106 #ifdef ASSERT
107 private:
108 int _java_call_counter;
109
110 public:
111 int java_call_counter() { return _java_call_counter; }
112 void inc_java_call_counter() { _java_call_counter++; }
113 void dec_java_call_counter() {
114 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
115 _java_call_counter--;
116 }
117 private: // restore original namespace restriction
118 #endif // ifdef ASSERT
119
120 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state
121
122 ThreadFunction _entry_point;
123
124 JNIEnv _jni_environment;
125
126 // Deopt support
127 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization
128
129 nmethod* _deopt_nmethod; // nmethod that is currently being deoptimized
130 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays
131 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped
132 // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They
133 // will be carried out as soon as possible which, in most cases, is just before deoptimization of
134 // the frame, when control returns to it.
135 JvmtiDeferredUpdates* _jvmti_deferred_updates;
136
137 // Handshake value for fixing 6243940. We need a place for the i2c
138 // adapter to store the callee Method*. This value is NEVER live
139 // across a gc point so it does NOT have to be gc'd
140 // The handshake is open ended since we can't be certain that it will
141 // be nulled. This is because we rarely ever see the race and end up
142 // in handle_wrong_method which is the backend of the handshake. See
143 // code in i2c adapters and handle_wrong_method.
144
145 Method* _callee_target;
146
147 // Used to pass back results to the interpreter or generated code running Java code.
148 oop _vm_result_oop; // oop result is GC-preserved
149 Metadata* _vm_result_metadata; // non-oop result
150
151 // See ReduceInitialCardMarks: this holds the precise space interval of
152 // the most recent slow path allocation for which compiled code has
153 // elided card-marks for performance along the fast-path.
154 MemRegion _deferred_card_mark;
155
156 ObjectMonitor* volatile _current_pending_monitor; // ObjectMonitor this thread is waiting to lock
157 bool _current_pending_monitor_is_from_java; // locking is from Java code
158 ObjectMonitor* volatile _current_waiting_monitor; // ObjectMonitor on which this thread called Object.wait()
159
160 // Active_handles points to a block of handles
161 JNIHandleBlock* _active_handles;
162
163 // One-element thread local free list
164 JNIHandleBlock* _free_handle_block;
165
166 // ID used as owner for inflated monitors. Same as the j.l.Thread.tid of the
167 // current _vthread object, except during creation of the primordial and JNI
168 // attached thread cases where this field can have a temporary value.
169 int64_t _monitor_owner_id;
170
171 public:
172 void set_monitor_owner_id(int64_t id) {
173 ThreadIdentifier::verify_id(id);
174 _monitor_owner_id = id;
175 }
176 int64_t monitor_owner_id() const {
177 int64_t id = _monitor_owner_id;
178 ThreadIdentifier::verify_id(id);
179 return id;
180 }
181
182 // For tracking the heavyweight monitor the thread is pending on.
183 ObjectMonitor* current_pending_monitor() {
184 // Use Atomic::load() to prevent data race between concurrent modification and
185 // concurrent readers, e.g. ThreadService::get_current_contended_monitor().
186 // Especially, reloading pointer from thread after null check must be prevented.
187 return Atomic::load(&_current_pending_monitor);
188 }
189 void set_current_pending_monitor(ObjectMonitor* monitor) {
190 Atomic::store(&_current_pending_monitor, monitor);
191 }
192 void set_current_pending_monitor_is_from_java(bool from_java) {
193 _current_pending_monitor_is_from_java = from_java;
194 }
195 bool current_pending_monitor_is_from_java() {
196 return _current_pending_monitor_is_from_java;
197 }
198 ObjectMonitor* current_waiting_monitor() {
199 // See the comment in current_pending_monitor() above.
200 return Atomic::load(&_current_waiting_monitor);
201 }
202 void set_current_waiting_monitor(ObjectMonitor* monitor) {
203 Atomic::store(&_current_waiting_monitor, monitor);
204 }
205
206 // JNI handle support
207 JNIHandleBlock* active_handles() const { return _active_handles; }
208 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
209 JNIHandleBlock* free_handle_block() const { return _free_handle_block; }
210 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
211
212 void push_jni_handle_block();
213 void pop_jni_handle_block();
214
215 private:
216 enum SuspendFlags {
217 // NOTE: avoid using the sign-bit as cc generates different test code
218 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077
219 _trace_flag = 0x00000004U, // call tracing backend
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_trace_flag();
231 inline void clear_trace_flag();
232 inline void set_obj_deopt_flag();
233 inline void clear_obj_deopt_flag();
234 bool is_trace_suspend() { return (_suspend_flags & _trace_flag) != 0; }
235 bool is_obj_deopt_suspend() { return (_suspend_flags & _obj_deopt) != 0; }
236
237 // Asynchronous exception support
238 private:
239 friend class InstallAsyncExceptionHandshake;
240 friend class AsyncExceptionHandshake;
241 friend class HandshakeState;
242
243 void handle_async_exception(oop java_throwable);
244 public:
245 void install_async_exception(AsyncExceptionHandshake* aec = nullptr);
246 bool has_async_exception_condition();
247 inline void set_pending_unsafe_access_error();
248 static void send_async_exception(JavaThread* jt, oop java_throwable);
249
250 class NoAsyncExceptionDeliveryMark : public StackObj {
251 friend JavaThread;
252 JavaThread *_target;
253 inline NoAsyncExceptionDeliveryMark(JavaThread *t);
254 inline ~NoAsyncExceptionDeliveryMark();
255 };
256
257 // Safepoint support
258 public: // Expose _thread_state for SafeFetchInt()
259 volatile JavaThreadState _thread_state;
260 ThreadSafepointState* _safepoint_state; // Holds information about a thread during a safepoint
261 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened
262 NOT_PRODUCT(bool _requires_cross_modify_fence;) // State used by VerifyCrossModifyFence
263 #ifdef ASSERT
264 // Debug support for checking if code allows safepoints or not.
265 // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
266 // mutex, or blocking on an object synchronizer (Java locking).
267 // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
268 // the above cases. The class NoSafepointVerifier is used to set this counter.
269 int _no_safepoint_count; // If 0, thread allow a safepoint to happen
270
271 public:
272 void inc_no_safepoint_count() { _no_safepoint_count++; }
273 void dec_no_safepoint_count() { _no_safepoint_count--; }
274 bool is_in_no_safepoint_scope() { return _no_safepoint_count > 0; }
275 #endif // ASSERT
276 public:
277 // These functions check conditions before possibly going to a safepoint.
278 // including NoSafepointVerifier.
279 void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
280 void check_possible_safepoint() NOT_DEBUG_RETURN;
281
282 #ifdef ASSERT
283 private:
284 volatile uint64_t _visited_for_critical_count;
285
286 public:
287 void set_visited_for_critical_count(uint64_t safepoint_id) {
288 assert(_visited_for_critical_count == 0, "Must be reset before set");
289 assert((safepoint_id & 0x1) == 1, "Must be odd");
290 _visited_for_critical_count = safepoint_id;
291 }
292 void reset_visited_for_critical_count(uint64_t safepoint_id) {
293 assert(_visited_for_critical_count == safepoint_id, "Was not visited");
294 _visited_for_critical_count = 0;
295 }
296 bool was_visited_for_critical_count(uint64_t safepoint_id) const {
297 return _visited_for_critical_count == safepoint_id;
298 }
299 #endif // ASSERT
300
301 // JavaThread termination support
302 public:
303 enum TerminatedTypes {
304 _not_terminated = 0xDEAD - 3,
305 _thread_exiting, // JavaThread::exit() has been called for this thread
306 _thread_gc_barrier_detached, // thread's GC barrier has been detached
307 _thread_terminated, // JavaThread is removed from thread list
308 _vm_exited // JavaThread is still executing native code, but VM is terminated
309 // only VM_Exit can set _vm_exited
310 };
311
312 private:
313 // In general a JavaThread's _terminated field transitions as follows:
314 //
315 // _not_terminated => _thread_exiting => _thread_gc_barrier_detached => _thread_terminated
316 //
317 // _vm_exited is a special value to cover the case of a JavaThread
318 // executing native code after the VM itself is terminated.
319 //
320 // A JavaThread that fails to JNI attach has these _terminated field transitions:
321 // _not_terminated => _thread_terminated
322 //
323 volatile TerminatedTypes _terminated;
324
325 jint _in_deopt_handler; // count of deoptimization
326 // handlers thread is in
327 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access
328 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
329 // never locked) when throwing an exception. Used by interpreter only.
330 #if INCLUDE_JVMTI
331 volatile bool _carrier_thread_suspended; // Carrier thread is externally suspended
332 bool _is_in_VTMS_transition; // thread is in virtual thread mount state transition
333 bool _is_disable_suspend; // JVMTI suspend is temporarily disabled; used on current thread only
334 bool _is_in_java_upcall; // JVMTI is doing a Java upcall, so JVMTI events must be hidden
335 bool _VTMS_transition_mark; // used for sync between VTMS transitions and disablers
336 bool _on_monitor_waited_event; // Avoid callee arg processing for enterSpecial when posting waited event
337 ObjectMonitor* _contended_entered_monitor; // Monitor for pending monitor_contended_entered callback
338 #ifdef ASSERT
339 bool _is_VTMS_transition_disabler; // thread currently disabled VTMS transitions
340 #endif
341 #endif
342
343 // JNI attach states:
344 enum JNIAttachStates {
345 _not_attaching_via_jni = 1, // thread is not attaching via JNI
346 _attaching_via_jni, // thread is attaching via JNI
347 _attached_via_jni // thread has attached via JNI
348 };
349
350 // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
351 // A native thread that is attaching via JNI starts with a value
352 // of _attaching_via_jni and transitions to _attached_via_jni.
353 volatile JNIAttachStates _jni_attach_state;
354
355 // In scope of an InternalOOMEMark?
356 bool _is_in_internal_oome_mark;
357
358 #if INCLUDE_JVMCI
359 // The _pending_* fields below are used to communicate extra information
360 // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
361
362 // Communicates the DeoptReason and DeoptAction of the uncommon trap
363 int _pending_deoptimization;
364
365 // Specifies whether the uncommon trap is to bci 0 of a synchronized method
366 // before the monitor has been acquired.
367 bool _pending_monitorenter;
368
369 // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
370 bool _pending_transfer_to_interpreter;
371
372 // An id of a speculation that JVMCI compiled code can use to further describe and
373 // uniquely identify the speculative optimization guarded by an uncommon trap.
374 // See JVMCINMethodData::SPECULATION_LENGTH_BITS for further details.
375 jlong _pending_failed_speculation;
376
377 // These fields are mutually exclusive in terms of live ranges.
378 union {
379 // Communicates the pc at which the most recent implicit exception occurred
380 // from the signal handler to a deoptimization stub.
381 address _implicit_exception_pc;
382
383 // Communicates an alternative call target to an i2c stub from a JavaCall .
384 address _alternate_call_target;
385 } _jvmci;
386
387 // The JVMCIRuntime in a JVMCI shared library
388 JVMCIRuntime* _libjvmci_runtime;
389
390 // Support for high precision, thread sensitive counters in JVMCI compiled code.
391 jlong* _jvmci_counters;
392
393 // Fast thread locals for use by JVMCI
394 jlong _jvmci_reserved0;
395 jlong _jvmci_reserved1;
396 oop _jvmci_reserved_oop0;
397
398 // This field is used to keep an nmethod visible to the GC so that it and its contained oops can
399 // be kept alive
400 nmethod* _live_nmethod;
401
402 public:
403 static jlong* _jvmci_old_thread_counters;
404 static void collect_counters(jlong* array, int length);
405
406 bool resize_counters(int current_size, int new_size);
407
408 static bool resize_all_jvmci_counters(int new_size);
409
410 void set_jvmci_reserved_oop0(oop value) {
411 _jvmci_reserved_oop0 = value;
412 }
413
414 oop get_jvmci_reserved_oop0() {
415 return _jvmci_reserved_oop0;
416 }
417
418 void set_jvmci_reserved0(jlong value) {
419 _jvmci_reserved0 = value;
420 }
421
422 jlong get_jvmci_reserved0() {
423 return _jvmci_reserved0;
424 }
425
426 void set_jvmci_reserved1(jlong value) {
427 _jvmci_reserved1 = value;
428 }
429
430 jlong get_jvmci_reserved1() {
431 return _jvmci_reserved1;
432 }
433
434 void set_live_nmethod(nmethod* nm) {
435 assert(_live_nmethod == nullptr, "only one");
436 _live_nmethod = nm;
437 }
438
439 void clear_live_nmethod() {
440 _live_nmethod = nullptr;
441 }
442
443 private:
444 #endif // INCLUDE_JVMCI
445
446 StackOverflow _stack_overflow_state;
447
448 void pretouch_stack();
449
450 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
451 // used to temp. parsing values into and out of the runtime system during exception handling for compiled
452 // code)
453 volatile oop _exception_oop; // Exception thrown in compiled code
454 volatile address _exception_pc; // PC where exception happened
455 volatile address _exception_handler_pc; // PC for handler of exception
456 volatile int _is_method_handle_return; // true (== 1) if the current exception PC is a MethodHandle call site.
457
458 private:
459 // support for JNI critical regions
460 jint _jni_active_critical; // count of entries into JNI critical region
461
462 // Checked JNI: function name requires exception check
463 char* _pending_jni_exception_check_fn;
464
465 // For deadlock detection.
466 int _depth_first_number;
467
468 // JVMTI PopFrame support
469 // This is set to popframe_pending to signal that top Java frame should be popped immediately
470 int _popframe_condition;
471
472 // If reallocation of scalar replaced objects fails, we throw OOM
473 // and during exception propagation, pop the top
474 // _frames_to_pop_failed_realloc frames, the ones that reference
475 // failed reallocations.
476 int _frames_to_pop_failed_realloc;
477
478 ContinuationEntry* _cont_entry;
479 intptr_t* _cont_fastpath; // the sp of the oldest known interpreted/call_stub/upcall_stub/native_wrapper
480 // frame inside the continuation that we know about
481 int _cont_fastpath_thread_state; // whether global thread state allows continuation fastpath (JVMTI)
482
483 // It's signed for error detection.
484 intx _held_monitor_count; // used by continuations for fast lock detection
485 intx _jni_monitor_count;
486 ObjectMonitor* _unlocked_inflated_monitor;
487
488 // This is the field we poke in the interpreter and native
489 // wrapper (Object.wait) to check for preemption.
490 address _preempt_alternate_return;
491 // When preempting on monitorenter we could have acquired the
492 // monitor after freezing all vthread frames. In that case we
493 // set this field so that in the preempt stub we call thaw again
494 // instead of unmounting.
495 bool _preemption_cancelled;
496 // For Object.wait() we set this field to know if we need to
497 // throw IE at the end of thawing before returning to Java.
498 bool _pending_interrupted_exception;
499 // We allow preemption on some klass initializion calls.
500 // We use this boolean to mark such calls.
501 bool _at_preemptable_init;
502
503 public:
504 bool preemption_cancelled() { return _preemption_cancelled; }
505 void set_preemption_cancelled(bool b) { _preemption_cancelled = b; }
506
507 bool pending_interrupted_exception() { return _pending_interrupted_exception; }
508 void set_pending_interrupted_exception(bool b) { _pending_interrupted_exception = b; }
509
510 bool preempting() { return _preempt_alternate_return != nullptr; }
511 void set_preempt_alternate_return(address val) { _preempt_alternate_return = val; }
512
513 bool at_preemptable_init() { return _at_preemptable_init; }
514 void set_at_preemptable_init(bool b) { _at_preemptable_init = b; }
515
516 #ifdef ASSERT
517 // Used for extra logging with -Xlog:continuation+preempt
518 InstanceKlass* _preempt_init_klass;
519
520 InstanceKlass* preempt_init_klass() { return _preempt_init_klass; }
521 void set_preempt_init_klass(InstanceKlass* ik) { _preempt_init_klass = ik; }
522 #endif
523
524 private:
525 friend class VMThread;
526 friend class ThreadWaitTransition;
527 friend class VM_Exit;
528
529 // Stack watermark barriers.
530 StackWatermarks _stack_watermarks;
531
532 public:
533 inline StackWatermarks* stack_watermarks() { return &_stack_watermarks; }
534
535 public:
536 // Constructor
537 JavaThread(MemTag mem_tag = mtThread); // delegating constructor
538 JavaThread(ThreadFunction entry_point, size_t stack_size = 0, MemTag mem_tag = mtThread);
539 ~JavaThread();
540
541 // Factory method to create a new JavaThread whose attach state is "is attaching"
542 static JavaThread* create_attaching_thread();
543
544 #ifdef ASSERT
545 // verify this JavaThread hasn't be published in the Threads::list yet
546 void verify_not_published();
547 #endif // ASSERT
548
549 StackOverflow* stack_overflow_state() { return &_stack_overflow_state; }
550
551 //JNI functiontable getter/setter for JVMTI jni function table interception API.
552 void set_jni_functions(struct JNINativeInterface_* functionTable) {
553 _jni_environment.functions = functionTable;
554 }
555 struct JNINativeInterface_* get_jni_functions() {
556 return (struct JNINativeInterface_ *)_jni_environment.functions;
557 }
558
559 // This function is called at thread creation to allow
560 // platform specific thread variables to be initialized.
561 void cache_global_variables();
562
563 // Executes Shutdown.shutdown()
564 void invoke_shutdown_hooks();
565
566 // Cleanup on thread exit
567 enum ExitType {
568 normal_exit,
569 jni_detach
570 };
571 void exit(bool destroy_vm, ExitType exit_type = normal_exit);
572
573 void cleanup_failed_attach_current_thread(bool is_daemon);
574
575 // Testers
576 virtual bool is_Java_thread() const { return true; }
577 virtual bool can_call_java() const { return true; }
578
579 virtual bool is_active_Java_thread() const;
580
581 // Thread oop. threadObj() can be null for initial JavaThread
582 // (or for threads attached via JNI)
583 oop threadObj() const;
584 void set_threadOopHandles(oop p);
585 oop vthread() const;
586 void set_vthread(oop p);
587 oop scopedValueCache() const;
588 void set_scopedValueCache(oop p);
589 void clear_scopedValueBindings();
590 oop jvmti_vthread() const;
591 void set_jvmti_vthread(oop p);
592 oop vthread_or_thread() const;
593
594 // Prepare thread and add to priority queue. If a priority is
595 // not specified, use the priority of the thread object. Threads_lock
596 // must be held while this function is called.
597 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
598
599 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; }
600 address saved_exception_pc() { return _saved_exception_pc; }
601
602 ThreadFunction entry_point() const { return _entry_point; }
603
604 // Allocates a new Java level thread object for this thread. thread_name may be null.
605 void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
606
607 // Last frame anchor routines
608
609 JavaFrameAnchor* frame_anchor(void) { return &_anchor; }
610
611 // last_Java_sp
612 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); }
613 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); }
614
615 // last_Java_pc
616
617 address last_Java_pc(void) { return _anchor.last_Java_pc(); }
618
619 // Safepoint support
620 inline JavaThreadState thread_state() const;
621 inline void set_thread_state(JavaThreadState s);
622 inline void set_thread_state_fence(JavaThreadState s); // fence after setting thread state
623 inline ThreadSafepointState* safepoint_state() const;
624 inline void set_safepoint_state(ThreadSafepointState* state);
625 inline bool is_at_poll_safepoint();
626
627 // JavaThread termination and lifecycle support:
628 void smr_delete();
629 bool on_thread_list() const { return _on_thread_list; }
630 void set_on_thread_list() { _on_thread_list = true; }
631
632 // thread has called JavaThread::exit(), thread's GC barrier is detached
633 // or thread is terminated
634 bool is_exiting() const;
635 // thread's GC barrier is NOT detached and thread is NOT terminated
636 bool is_oop_safe() const;
637 // thread is terminated (no longer on the threads list); the thread must
638 // be protected by a ThreadsListHandle to avoid potential crashes.
639 bool check_is_terminated(TerminatedTypes l_terminated) const {
640 return l_terminated == _thread_terminated || l_terminated == _vm_exited;
641 }
642 bool is_terminated() const;
643 void set_terminated(TerminatedTypes t);
644
645 void block_if_vm_exited();
646
647 bool doing_unsafe_access() { return _doing_unsafe_access; }
648 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; }
649
650 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; }
651 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
652
653 SafepointMechanism::ThreadData* poll_data() { return &_poll_data; }
654
655 static ByteSize polling_word_offset() {
656 ByteSize offset = byte_offset_of(Thread, _poll_data) +
657 byte_offset_of(SafepointMechanism::ThreadData, _polling_word);
658 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
659 assert(in_bytes(offset) < 128, "Offset >= 128");
660 return offset;
661 }
662
663 static ByteSize polling_page_offset() {
664 ByteSize offset = byte_offset_of(Thread, _poll_data) +
665 byte_offset_of(SafepointMechanism::ThreadData, _polling_page);
666 // At least on x86_64, safepoint polls encode the offset as disp8 imm.
667 assert(in_bytes(offset) < 128, "Offset >= 128");
668 return offset;
669 }
670
671 void set_requires_cross_modify_fence(bool val) PRODUCT_RETURN NOT_PRODUCT({ _requires_cross_modify_fence = val; })
672
673 // Continuation support
674 ContinuationEntry* last_continuation() const { return _cont_entry; }
675 void set_cont_fastpath(intptr_t* x) { _cont_fastpath = x; }
676 void push_cont_fastpath(intptr_t* sp) { if (sp > _cont_fastpath) _cont_fastpath = sp; }
677 void set_cont_fastpath_thread_state(bool x) { _cont_fastpath_thread_state = (int)x; }
678 intptr_t* raw_cont_fastpath() const { return _cont_fastpath; }
679 bool cont_fastpath() const { return _cont_fastpath == nullptr && _cont_fastpath_thread_state != 0; }
680 bool cont_fastpath_thread_state() const { return _cont_fastpath_thread_state != 0; }
681
682 void inc_held_monitor_count(intx i = 1, bool jni = false);
683 void dec_held_monitor_count(intx i = 1, bool jni = false);
684
685 intx held_monitor_count() { return _held_monitor_count; }
686 intx jni_monitor_count() { return _jni_monitor_count; }
687 void clear_jni_monitor_count() { _jni_monitor_count = 0; }
688
689 // Support for SharedRuntime::monitor_exit_helper()
690 ObjectMonitor* unlocked_inflated_monitor() const { return _unlocked_inflated_monitor; }
691 void clear_unlocked_inflated_monitor() {
692 _unlocked_inflated_monitor = nullptr;
693 }
694
695 inline bool is_vthread_mounted() const;
696 inline const ContinuationEntry* vthread_continuation() const;
697
698 private:
699 DEBUG_ONLY(void verify_frame_info();)
700
701 // Support for thread handshake operations
702 HandshakeState _handshake;
703 public:
704 HandshakeState* handshake_state() { return &_handshake; }
705
706 // A JavaThread can always safely operate on it self and other threads
707 // can do it safely if they are the active handshaker.
708 bool is_handshake_safe_for(Thread* th) const {
709 return _handshake.active_handshaker() == th || this == th;
710 }
711
712 // Suspend/resume support for JavaThread
713 // higher-level suspension/resume logic called by the public APIs
714 bool java_suspend();
715 bool java_resume();
716 bool is_suspended() { return _handshake.is_suspended(); }
717
718 // Check for async exception in addition to safepoint.
719 static void check_special_condition_for_native_trans(JavaThread *thread);
720
721 // Synchronize with another thread that is deoptimizing objects of the
722 // current thread, i.e. reverts optimizations based on escape analysis.
723 void wait_for_object_deoptimization();
724
725 #if INCLUDE_JVMTI
726 inline void set_carrier_thread_suspended();
727 inline void clear_carrier_thread_suspended();
728
729 bool is_carrier_thread_suspended() const {
730 return _carrier_thread_suspended;
731 }
732
733 bool is_in_VTMS_transition() const { return _is_in_VTMS_transition; }
734 void set_is_in_VTMS_transition(bool val);
735
736 bool is_disable_suspend() const { return _is_disable_suspend; }
737 void toggle_is_disable_suspend() { _is_disable_suspend = !_is_disable_suspend; };
738
739 bool is_in_java_upcall() const { return _is_in_java_upcall; }
740 void toggle_is_in_java_upcall() { _is_in_java_upcall = !_is_in_java_upcall; };
741
742 bool VTMS_transition_mark() const { return Atomic::load(&_VTMS_transition_mark); }
743 void set_VTMS_transition_mark(bool val) { Atomic::store(&_VTMS_transition_mark, val); }
744
745 // Temporarily skip posting JVMTI events for safety reasons when executions is in a critical section:
746 // - is in a VTMS transition (_is_in_VTMS_transition)
747 // - is in an interruptLock or similar critical section (_is_disable_suspend)
748 // - JVMTI is making a Java upcall (_is_in_java_upcall)
749 bool should_hide_jvmti_events() const { return _is_in_VTMS_transition || _is_disable_suspend || _is_in_java_upcall; }
750
751 bool on_monitor_waited_event() { return _on_monitor_waited_event; }
752 void set_on_monitor_waited_event(bool val) { _on_monitor_waited_event = val; }
753
754 bool pending_contended_entered_event() { return _contended_entered_monitor != nullptr; }
755 ObjectMonitor* contended_entered_monitor() { return _contended_entered_monitor; }
756 #ifdef ASSERT
757 bool is_VTMS_transition_disabler() const { return _is_VTMS_transition_disabler; }
758 void set_is_VTMS_transition_disabler(bool val);
759 #endif
760 #endif
761
762 void set_contended_entered_monitor(ObjectMonitor* val) NOT_JVMTI_RETURN JVMTI_ONLY({ _contended_entered_monitor = val; })
763
764 // Support for object deoptimization and JFR suspension
765 void handle_special_runtime_exit_condition();
766 bool has_special_runtime_exit_condition() {
767 return (_suspend_flags & (_obj_deopt JFR_ONLY(| _trace_flag))) != 0;
768 }
769
770 // Stack-locking support (not for LM_LIGHTWEIGHT)
771 bool is_lock_owned(address adr) const;
772
773 // Accessors for vframe array top
774 // The linked list of vframe arrays are sorted on sp. This means when we
775 // unpack the head must contain the vframe array to unpack.
776 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
777 vframeArray* vframe_array_head() const { return _vframe_array_head; }
778
779 // Side structure for deferring update of java frame locals until deopt occurs
780 JvmtiDeferredUpdates* deferred_updates() const { return _jvmti_deferred_updates; }
781 void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; }
782
783 // These only really exist to make debugging deopt problems simpler
784
785 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
786 vframeArray* vframe_array_last() const { return _vframe_array_last; }
787
788 // The special resourceMark used during deoptimization
789
790 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; }
791 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; }
792
793 void set_deopt_compiled_method(nmethod* nm) { _deopt_nmethod = nm; }
794 nmethod* deopt_compiled_method() { return _deopt_nmethod; }
795
796 Method* callee_target() const { return _callee_target; }
797 void set_callee_target (Method* x) { _callee_target = x; }
798
799 // Oop results of vm runtime calls
800 oop vm_result_oop() const { return _vm_result_oop; }
801 void set_vm_result_oop(oop x) { _vm_result_oop = x; }
802
803 void set_vm_result_metadata(Metadata* x) { _vm_result_metadata = x; }
804
805 MemRegion deferred_card_mark() const { return _deferred_card_mark; }
806 void set_deferred_card_mark(MemRegion mr) { _deferred_card_mark = mr; }
807
808 // Is thread in scope of an InternalOOMEMark?
809 bool is_in_internal_oome_mark() const { return _is_in_internal_oome_mark; }
810 void set_is_in_internal_oome_mark(bool b) { _is_in_internal_oome_mark = b; }
811
812 #if INCLUDE_JVMCI
813 jlong pending_failed_speculation() const { return _pending_failed_speculation; }
814 void set_pending_monitorenter(bool b) { _pending_monitorenter = b; }
815 void set_pending_deoptimization(int reason) { _pending_deoptimization = reason; }
816 void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
817 void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
818 void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == nullptr, "must be"); _jvmci._alternate_call_target = a; }
819 void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == nullptr, "must be"); _jvmci._implicit_exception_pc = a; }
820
821 JVMCIRuntime* libjvmci_runtime() const { return _libjvmci_runtime; }
822 void set_libjvmci_runtime(JVMCIRuntime* rt) {
823 assert((_libjvmci_runtime == nullptr && rt != nullptr) || (_libjvmci_runtime != nullptr && rt == nullptr), "must be");
824 _libjvmci_runtime = rt;
825 }
826 #endif // INCLUDE_JVMCI
827
828 // Exception handling for compiled methods
829 oop exception_oop() const;
830 address exception_pc() const { return _exception_pc; }
831
832 void set_exception_oop(oop o);
833 void set_exception_pc(address a) { _exception_pc = a; }
834 void set_exception_handler_pc(address a) { _exception_handler_pc = a; }
835 void set_is_method_handle_return(bool value) { _is_method_handle_return = value ? 1 : 0; }
836
837 void clear_exception_oop_and_pc() {
838 set_exception_oop(nullptr);
839 set_exception_pc(nullptr);
840 }
841
842 // Check if address is in the usable part of the stack (excludes protected
843 // guard pages). Can be applied to any thread and is an approximation for
844 // using is_in_live_stack when the query has to happen from another thread.
845 bool is_in_usable_stack(address adr) const {
846 return is_in_stack_range_incl(adr, _stack_overflow_state.stack_reserved_zone_base());
847 }
848
849 // Misc. accessors/mutators
850 static ByteSize scopedValueCache_offset() { return byte_offset_of(JavaThread, _scopedValueCache); }
851
852 // For assembly stub generation
853 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj); }
854 static ByteSize vthread_offset() { return byte_offset_of(JavaThread, _vthread); }
855 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment); }
856 static ByteSize pending_jni_exception_check_fn_offset() {
857 return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
858 }
859 static ByteSize last_Java_sp_offset() {
860 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
861 }
862 static ByteSize last_Java_pc_offset() {
863 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
864 }
865 static ByteSize frame_anchor_offset() {
866 return byte_offset_of(JavaThread, _anchor);
867 }
868 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target); }
869 static ByteSize vm_result_oop_offset() { return byte_offset_of(JavaThread, _vm_result_oop); }
870 static ByteSize vm_result_metadata_offset() { return byte_offset_of(JavaThread, _vm_result_metadata); }
871 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state); }
872 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc); }
873 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread); }
874 #if INCLUDE_JVMCI
875 static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
876 static ByteSize pending_monitorenter_offset() { return byte_offset_of(JavaThread, _pending_monitorenter); }
877 static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
878 static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
879 static ByteSize jvmci_counters_offset() { return byte_offset_of(JavaThread, _jvmci_counters); }
880 #endif // INCLUDE_JVMCI
881 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop); }
882 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc); }
883 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); }
884 static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
885
886 static ByteSize active_handles_offset() { return byte_offset_of(JavaThread, _active_handles); }
887
888 // StackOverflow offsets
889 static ByteSize stack_overflow_limit_offset() {
890 return byte_offset_of(JavaThread, _stack_overflow_state._stack_overflow_limit);
891 }
892 static ByteSize stack_guard_state_offset() {
893 return byte_offset_of(JavaThread, _stack_overflow_state._stack_guard_state);
894 }
895 static ByteSize reserved_stack_activation_offset() {
896 return byte_offset_of(JavaThread, _stack_overflow_state._reserved_stack_activation);
897 }
898 static ByteSize shadow_zone_safe_limit() {
899 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_safe_limit);
900 }
901 static ByteSize shadow_zone_growth_watermark() {
902 return byte_offset_of(JavaThread, _stack_overflow_state._shadow_zone_growth_watermark);
903 }
904
905 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags); }
906
907 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
908 static ByteSize should_post_on_exceptions_flag_offset() {
909 return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
910 }
911 static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
912 NOT_PRODUCT(static ByteSize requires_cross_modify_fence_offset() { return byte_offset_of(JavaThread, _requires_cross_modify_fence); })
913
914 static ByteSize monitor_owner_id_offset() { return byte_offset_of(JavaThread, _monitor_owner_id); }
915
916 static ByteSize cont_entry_offset() { return byte_offset_of(JavaThread, _cont_entry); }
917 static ByteSize cont_fastpath_offset() { return byte_offset_of(JavaThread, _cont_fastpath); }
918 static ByteSize held_monitor_count_offset() { return byte_offset_of(JavaThread, _held_monitor_count); }
919 static ByteSize jni_monitor_count_offset() { return byte_offset_of(JavaThread, _jni_monitor_count); }
920 static ByteSize preemption_cancelled_offset() { return byte_offset_of(JavaThread, _preemption_cancelled); }
921 static ByteSize preempt_alternate_return_offset() { return byte_offset_of(JavaThread, _preempt_alternate_return); }
922 static ByteSize unlocked_inflated_monitor_offset() { return byte_offset_of(JavaThread, _unlocked_inflated_monitor); }
923
924 #if INCLUDE_JVMTI
925 static ByteSize is_in_VTMS_transition_offset() { return byte_offset_of(JavaThread, _is_in_VTMS_transition); }
926 static ByteSize is_disable_suspend_offset() { return byte_offset_of(JavaThread, _is_disable_suspend); }
927 #endif
928
929 // Returns the jni environment for this thread
930 JNIEnv* jni_environment() { return &_jni_environment; }
931
932 // Returns the current thread as indicated by the given JNIEnv.
933 // We don't assert it is Thread::current here as that is done at the
934 // external JNI entry points where the JNIEnv is passed into the VM.
935 static JavaThread* thread_from_jni_environment(JNIEnv* env) {
936 JavaThread* current = reinterpret_cast<JavaThread*>(((intptr_t)env - in_bytes(jni_environment_offset())));
937 // We can't normally get here in a thread that has completed its
938 // execution and so "is_terminated", except when the call is from
939 // AsyncGetCallTrace, which can be triggered by a signal at any point in
940 // a thread's lifecycle. A thread is also considered terminated if the VM
941 // has exited, so we have to check this and block in case this is a daemon
942 // thread returning to the VM (the JNI DirectBuffer entry points rely on
943 // this).
944 if (current->is_terminated()) {
945 current->block_if_vm_exited();
946 }
947 return current;
948 }
949
950 // JNI critical regions. These can nest.
951 bool in_critical() { return _jni_active_critical > 0; }
952 bool in_last_critical() { return _jni_active_critical == 1; }
953 inline void enter_critical();
954 void exit_critical() {
955 assert(Thread::current() == this, "this must be current thread");
956 _jni_active_critical--;
957 assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
958 }
959
960 // Atomic version; invoked by a thread other than the owning thread.
961 bool in_critical_atomic() { return Atomic::load(&_jni_active_critical) > 0; }
962
963 // Checked JNI: is the programmer required to check for exceptions, if so specify
964 // which function name. Returning to a Java frame should implicitly clear the
965 // pending check, this is done for Native->Java transitions (i.e. user JNI code).
966 // VM->Java transitions are not cleared, it is expected that JNI code enclosed
967 // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
968 bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != nullptr; }
969 void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = nullptr; }
970 const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
971 void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
972
973 // For deadlock detection
974 int depth_first_number() { return _depth_first_number; }
975 void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
976
977 public:
978 bool in_deopt_handler() const { return _in_deopt_handler > 0; }
979 void inc_in_deopt_handler() { _in_deopt_handler++; }
980 void dec_in_deopt_handler() {
981 assert(_in_deopt_handler > 0, "mismatched deopt nesting");
982 if (_in_deopt_handler > 0) { // robustness
983 _in_deopt_handler--;
984 }
985 }
986
987 private:
988 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
989
990 // factor out low-level mechanics for use in both normal and error cases
991 const char* get_thread_name_string(char* buf = nullptr, int buflen = 0) const;
992
993 public:
994
995 // Frame iteration; calls the function f for all frames on the stack
996 void frames_do(void f(frame*, const RegisterMap*));
997
998 // Memory operations
999 void oops_do_frames(OopClosure* f, NMethodClosure* cf);
1000 void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
1001
1002 // GC operations
1003 virtual void nmethods_do(NMethodClosure* cf);
1004
1005 // RedefineClasses Support
1006 void metadata_do(MetadataClosure* f);
1007
1008 // Debug method asserting thread states are correct during a handshake operation.
1009 DEBUG_ONLY(void verify_states_for_handshake();)
1010
1011 // Misc. operations
1012 const char* name() const;
1013 const char* name_raw() const;
1014 const char* type_name() const { return "JavaThread"; }
1015 static const char* name_for(oop thread_obj);
1016
1017 void print_on(outputStream* st, bool print_extended_info) const;
1018 void print_on(outputStream* st) const { print_on(st, false); }
1019 void print() const;
1020 void print_thread_state_on(outputStream*) const;
1021 void print_on_error(outputStream* st, char* buf, int buflen) const;
1022 void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1023 void verify();
1024
1025 // Accessing frames
1026 frame last_frame() {
1027 _anchor.make_walkable();
1028 return pd_last_frame();
1029 }
1030 javaVFrame* last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(last_frame(), reg_map); }
1031
1032 frame carrier_last_frame(RegisterMap* reg_map);
1033 javaVFrame* carrier_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(carrier_last_frame(reg_map), reg_map); }
1034
1035 frame vthread_last_frame();
1036 javaVFrame* vthread_last_java_vframe(RegisterMap* reg_map) { return last_java_vframe(vthread_last_frame(), reg_map); }
1037
1038 frame platform_thread_last_frame(RegisterMap* reg_map);
1039 javaVFrame* platform_thread_last_java_vframe(RegisterMap* reg_map) {
1040 return last_java_vframe(platform_thread_last_frame(reg_map), reg_map);
1041 }
1042
1043 javaVFrame* last_java_vframe(const frame f, RegisterMap* reg_map);
1044
1045 // Returns method at 'depth' java or native frames down the stack
1046 // Used for security checks
1047 Klass* security_get_caller_class(int depth);
1048
1049 // Print stack trace in external format
1050 // These variants print carrier/platform thread information only.
1051 void print_stack_on(outputStream* st);
1052 void print_stack() { print_stack_on(tty); }
1053 // This prints the currently mounted virtual thread.
1054 void print_vthread_stack_on(outputStream* st);
1055 // This prints the active stack: either carrier/platform or virtual.
1056 void print_active_stack_on(outputStream* st);
1057 // Print current stack trace for checked JNI warnings and JNI fatal errors.
1058 // This is the external format from above, but selecting the platform
1059 // or vthread as applicable.
1060 void print_jni_stack();
1061
1062 // Print stack traces in various internal formats
1063 void trace_stack() PRODUCT_RETURN;
1064 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN;
1065 void trace_frames() PRODUCT_RETURN;
1066
1067 // Print an annotated view of the stack frames
1068 void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1069 void validate_frame_layout() {
1070 print_frame_layout(0, true);
1071 }
1072
1073 // Function for testing deoptimization
1074 void deoptimize();
1075 void make_zombies();
1076
1077 void deoptimize_marked_methods();
1078
1079 public:
1080 // Returns the running thread as a JavaThread
1081 static JavaThread* current() {
1082 return JavaThread::cast(Thread::current());
1083 }
1084
1085 // Returns the current thread as a JavaThread, or nullptr if not attached
1086 static inline JavaThread* current_or_null();
1087
1088 // Casts
1089 static JavaThread* cast(Thread* t) {
1090 assert(t->is_Java_thread(), "incorrect cast to JavaThread");
1091 return static_cast<JavaThread*>(t);
1092 }
1093
1094 static const JavaThread* cast(const Thread* t) {
1095 assert(t->is_Java_thread(), "incorrect cast to const JavaThread");
1096 return static_cast<const JavaThread*>(t);
1097 }
1098
1099 // Returns the active Java thread. Do not use this if you know you are calling
1100 // from a JavaThread, as it's slower than JavaThread::current. If called from
1101 // the VMThread, it also returns the JavaThread that instigated the VMThread's
1102 // operation. You may not want that either.
1103 static JavaThread* active();
1104
1105 protected:
1106 virtual void pre_run();
1107 virtual void run();
1108 void thread_main_inner();
1109 virtual void post_run();
1110
1111 public:
1112 // Thread local information maintained by JVMTI.
1113 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; }
1114 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1115 // getter is used to get this JavaThread's JvmtiThreadState if it has
1116 // one which means null can be returned. JvmtiThreadState::state_for()
1117 // is used to get the specified JavaThread's JvmtiThreadState if it has
1118 // one or it allocates a new JvmtiThreadState for the JavaThread and
1119 // returns it. JvmtiThreadState::state_for() will return null only if
1120 // the specified JavaThread is exiting.
1121 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; }
1122 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1123
1124 #if INCLUDE_JVMTI
1125 // Rebind JVMTI thread state from carrier to virtual or from virtual to carrier.
1126 JvmtiThreadState *rebind_to_jvmti_thread_state_of(oop thread_oop);
1127 #endif
1128
1129 // JVMTI PopFrame support
1130 // Setting and clearing popframe_condition
1131 // All of these enumerated values are bits. popframe_pending
1132 // indicates that a PopFrame() has been requested and not yet been
1133 // completed. popframe_processing indicates that that PopFrame() is in
1134 // the process of being completed. popframe_force_deopt_reexecution_bit
1135 // indicates that special handling is required when returning to a
1136 // deoptimized caller.
1137 enum PopCondition {
1138 popframe_inactive = 0x00,
1139 popframe_pending_bit = 0x01,
1140 popframe_processing_bit = 0x02,
1141 popframe_force_deopt_reexecution_bit = 0x04
1142 };
1143 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; }
1144 void set_popframe_condition(PopCondition c) { _popframe_condition = c; }
1145 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; }
1146 void clear_popframe_condition() { _popframe_condition = popframe_inactive; }
1147 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); }
1148 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; }
1149 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
1150
1151 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); }
1152 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; }
1153 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; }
1154
1155 int frames_to_pop_failed_realloc() const { return _frames_to_pop_failed_realloc; }
1156 void set_frames_to_pop_failed_realloc(int nb) { _frames_to_pop_failed_realloc = nb; }
1157 void dec_frames_to_pop_failed_realloc() { _frames_to_pop_failed_realloc--; }
1158
1159 private:
1160 // Saved incoming arguments to popped frame.
1161 // Used only when popped interpreted frame returns to deoptimized frame.
1162 void* _popframe_preserved_args;
1163 int _popframe_preserved_args_size;
1164
1165 public:
1166 void popframe_preserve_args(ByteSize size_in_bytes, void* start);
1167 void* popframe_preserved_args();
1168 ByteSize popframe_preserved_args_size();
1169 WordSize popframe_preserved_args_size_in_words();
1170 void popframe_free_preserved_args();
1171
1172
1173 private:
1174 JvmtiThreadState *_jvmti_thread_state;
1175
1176 // Used by the interpreter in fullspeed mode for frame pop, method
1177 // entry, method exit and single stepping support. This field is
1178 // only set to non-zero at a safepoint or using a direct handshake
1179 // (see EnterInterpOnlyModeClosure).
1180 // It can be set to zero asynchronously to this threads execution (i.e., without
1181 // safepoint/handshake or a lock) so we have to be very careful.
1182 // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
1183 int _interp_only_mode;
1184
1185 public:
1186 // used by the interpreter for fullspeed debugging support (see above)
1187 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
1188 bool is_interp_only_mode() { return (_interp_only_mode != 0); }
1189 int get_interp_only_mode() { return _interp_only_mode; }
1190 int set_interp_only_mode(int val) { return _interp_only_mode = val; }
1191 void increment_interp_only_mode() { ++_interp_only_mode; }
1192 void decrement_interp_only_mode() { --_interp_only_mode; }
1193
1194 // support for cached flag that indicates whether exceptions need to be posted for this thread
1195 // if this is false, we can avoid deoptimizing when events are thrown
1196 // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
1197 private:
1198 int _should_post_on_exceptions_flag;
1199
1200 public:
1201 void set_should_post_on_exceptions_flag(int val) { _should_post_on_exceptions_flag = val; }
1202
1203 private:
1204 ThreadStatistics *_thread_stat;
1205
1206 public:
1207 ThreadStatistics* get_thread_stat() const { return _thread_stat; }
1208
1209 // Return a blocker object for which this thread is blocked parking.
1210 oop current_park_blocker();
1211
1212 private:
1213 static size_t _stack_size_at_create;
1214
1215 public:
1216 static inline size_t stack_size_at_create(void) {
1217 return _stack_size_at_create;
1218 }
1219 static inline void set_stack_size_at_create(size_t value) {
1220 _stack_size_at_create = value;
1221 }
1222
1223 // Machine dependent stuff
1224 #include OS_CPU_HEADER(javaThread)
1225
1226 // JSR166 per-thread parker
1227 private:
1228 Parker _parker;
1229 public:
1230 Parker* parker() { return &_parker; }
1231
1232 public:
1233 // clearing/querying jni attach status
1234 bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
1235 bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
1236 inline void set_done_attaching_via_jni();
1237
1238 // Stack dump assistance:
1239 // Track the class we want to initialize but for which we have to wait
1240 // on its init_lock() because it is already being initialized.
1241 void set_class_to_be_initialized(InstanceKlass* k);
1242 InstanceKlass* class_to_be_initialized() const;
1243
1244 // Track executing class initializer, see ThreadInClassInitializer
1245 void set_class_being_initialized(InstanceKlass* k);
1246 InstanceKlass* class_being_initialized() const;
1247
1248 private:
1249 InstanceKlass* _class_to_be_initialized;
1250 InstanceKlass* _class_being_initialized;
1251
1252 // java.lang.Thread.sleep support
1253 ParkEvent * _SleepEvent;
1254
1255 #if INCLUDE_JFR
1256 // Support for jdk.VirtualThreadPinned event
1257 freeze_result _last_freeze_fail_result;
1258 Ticks _last_freeze_fail_time;
1259 #endif
1260
1261 public:
1262 bool sleep(jlong millis);
1263 bool sleep_nanos(jlong nanos);
1264
1265 // java.lang.Thread interruption support
1266 void interrupt();
1267 bool is_interrupted(bool clear_interrupted);
1268
1269 #if INCLUDE_JFR
1270 // Support for jdk.VirtualThreadPinned event
1271 freeze_result last_freeze_fail_result() { return _last_freeze_fail_result; }
1272 Ticks& last_freeze_fail_time() { return _last_freeze_fail_time; }
1273 void set_last_freeze_fail_result(freeze_result result);
1274 #endif
1275 void post_vthread_pinned_event(EventVirtualThreadPinned* event, const char* op, freeze_result result) NOT_JFR_RETURN();
1276
1277
1278 // This is only for use by JVMTI RawMonitorWait. It emulates the actions of
1279 // the Java code in Object::wait which are not present in RawMonitorWait.
1280 bool get_and_clear_interrupted();
1281
1282 private:
1283 LockStack _lock_stack;
1284 OMCache _om_cache;
1285
1286 public:
1287 LockStack& lock_stack() { return _lock_stack; }
1288
1289 static ByteSize lock_stack_offset() { return byte_offset_of(JavaThread, _lock_stack); }
1290 // Those offsets are used in code generators to access the LockStack that is embedded in this
1291 // JavaThread structure. Those accesses are relative to the current thread, which
1292 // is typically in a dedicated register.
1293 static ByteSize lock_stack_top_offset() { return lock_stack_offset() + LockStack::top_offset(); }
1294 static ByteSize lock_stack_base_offset() { return lock_stack_offset() + LockStack::base_offset(); }
1295
1296 static ByteSize om_cache_offset() { return byte_offset_of(JavaThread, _om_cache); }
1297 static ByteSize om_cache_oops_offset() { return om_cache_offset() + OMCache::entries_offset(); }
1298
1299 void om_set_monitor_cache(ObjectMonitor* monitor);
1300 void om_clear_monitor_cache();
1301 ObjectMonitor* om_get_from_monitor_cache(oop obj);
1302
1303 static OopStorage* thread_oop_storage();
1304
1305 static void verify_cross_modify_fence_failure(JavaThread *thread) PRODUCT_RETURN;
1306
1307 // Helper function to create the java.lang.Thread object for a
1308 // VM-internal thread. The thread will have the given name and be
1309 // part of the System ThreadGroup.
1310 static Handle create_system_thread_object(const char* name, TRAPS);
1311
1312 // Helper function to start a VM-internal daemon thread.
1313 // E.g. ServiceThread, NotificationThread, CompilerThread etc.
1314 static void start_internal_daemon(JavaThread* current, JavaThread* target,
1315 Handle thread_oop, ThreadPriority prio);
1316
1317 // Helper function to do vm_exit_on_initialization for osthread
1318 // resource allocation failure.
1319 static void vm_exit_on_osthread_failure(JavaThread* thread);
1320
1321 // Deferred OopHandle release support
1322 private:
1323 // List of OopHandles to be released - guarded by the Service_lock.
1324 static OopHandleList* _oop_handle_list;
1325 // Add our OopHandles to the list for the service thread to release.
1326 void add_oop_handles_for_release();
1327 // Called by the ServiceThread to release the OopHandles.
1328 static void release_oop_handles();
1329 // Called by the ServiceThread to poll if there are any OopHandles to release.
1330 // Called when holding the Service_lock.
1331 static bool has_oop_handles_to_release() {
1332 return _oop_handle_list != nullptr;
1333 }
1334 };
1335
1336 inline JavaThread* JavaThread::current_or_null() {
1337 Thread* current = Thread::current_or_null();
1338 return current != nullptr ? JavaThread::cast(current) : nullptr;
1339 }
1340
1341 class UnlockFlagSaver {
1342 private:
1343 JavaThread* _thread;
1344 bool _do_not_unlock;
1345 public:
1346 UnlockFlagSaver(JavaThread* t) {
1347 _thread = t;
1348 _do_not_unlock = t->do_not_unlock_if_synchronized();
1349 t->set_do_not_unlock_if_synchronized(false);
1350 }
1351 ~UnlockFlagSaver() {
1352 _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
1353 }
1354 };
1355
1356 class JNIHandleMark : public StackObj {
1357 JavaThread* _thread;
1358 public:
1359 JNIHandleMark(JavaThread* thread) : _thread(thread) {
1360 thread->push_jni_handle_block();
1361 }
1362 ~JNIHandleMark() { _thread->pop_jni_handle_block(); }
1363 };
1364
1365 class PreemptableInitCall {
1366 JavaThread* _thread;
1367 bool _previous;
1368 DEBUG_ONLY(InstanceKlass* _previous_klass;)
1369 public:
1370 PreemptableInitCall(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1371 _previous = thread->at_preemptable_init();
1372 _thread->set_at_preemptable_init(true);
1373 DEBUG_ONLY(_previous_klass = _thread->preempt_init_klass();)
1374 DEBUG_ONLY(_thread->set_preempt_init_klass(ik));
1375 }
1376 ~PreemptableInitCall() {
1377 _thread->set_at_preemptable_init(_previous);
1378 DEBUG_ONLY(_thread->set_preempt_init_klass(_previous_klass));
1379 }
1380 };
1381
1382 class NoPreemptMark {
1383 ContinuationEntry* _ce;
1384 bool _unpin;
1385 public:
1386 NoPreemptMark(JavaThread* thread, bool ignore_mark = false) : _ce(thread->last_continuation()), _unpin(false) {
1387 if (_ce != nullptr && !ignore_mark) _unpin = _ce->pin();
1388 }
1389 ~NoPreemptMark() { if (_unpin) _ce->unpin(); }
1390 };
1391
1392 class ThreadOnMonitorWaitedEvent {
1393 JavaThread* _thread;
1394 public:
1395 ThreadOnMonitorWaitedEvent(JavaThread* thread) : _thread(thread) {
1396 JVMTI_ONLY(_thread->set_on_monitor_waited_event(true);)
1397 }
1398 ~ThreadOnMonitorWaitedEvent() { JVMTI_ONLY(_thread->set_on_monitor_waited_event(false);) }
1399 };
1400
1401 class ThreadInClassInitializer : public StackObj {
1402 JavaThread* _thread;
1403 InstanceKlass* _previous;
1404 public:
1405 ThreadInClassInitializer(JavaThread* thread, InstanceKlass* ik) : _thread(thread) {
1406 _previous = _thread->class_being_initialized();
1407 _thread->set_class_being_initialized(ik);
1408 }
1409 ~ThreadInClassInitializer() {
1410 _thread->set_class_being_initialized(_previous);
1411 }
1412 };
1413
1414 #endif // SHARE_RUNTIME_JAVATHREAD_HPP