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_THREAD_HPP
27 #define SHARE_RUNTIME_THREAD_HPP
28
29 #include "gc/shared/gcThreadLocalData.hpp"
30 #include "gc/shared/threadLocalAllocBuffer.hpp"
31 #include "jni.h"
32 #include "memory/allocation.hpp"
33 #include "runtime/atomicAccess.hpp"
34 #include "runtime/globals.hpp"
35 #include "runtime/os.hpp"
36 #include "runtime/safepointMechanism.hpp"
37 #include "runtime/threadHeapSampler.hpp"
38 #include "runtime/threadLocalStorage.hpp"
39 #include "runtime/threadStatisticalInfo.hpp"
40 #include "runtime/unhandledOops.hpp"
41 #include "utilities/globalDefinitions.hpp"
42 #include "utilities/macros.hpp"
43 #if INCLUDE_JFR
44 #include "jfr/support/jfrThreadExtension.hpp"
45 #endif
46
47 class CompilerThread;
48 class HandleArea;
49 class HandleMark;
50 class JvmtiRawMonitor;
51 class NMethodClosure;
52 class Metadata;
53 class OopClosure;
54 class OSThread;
55 class ParkEvent;
56 class ResourceArea;
57 class SafeThreadsListPtr;
58 class ThreadClosure;
59 class ThreadsList;
60 class ThreadsSMRSupport;
61 class VMErrorCallback;
62
63
64 DEBUG_ONLY(class ResourceMark;)
65
66 class WorkerThread;
67
68 class JavaThread;
69
70 // Class hierarchy
71 // - Thread
72 // - JavaThread
73 // - various subclasses eg CompilerThread, ServiceThread
74 // - NonJavaThread
75 // - NamedThread
76 // - VMThread
77 // - ConcurrentGCThread
78 // - WorkerThread
79 // - WatcherThread
80 // - JfrThreadSampler
81 // - JfrCPUSamplerThread
82 // - LogAsyncWriter
83 //
84 // All Thread subclasses must be either JavaThread or NonJavaThread.
85 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
86 // a partially constructed/destroyed Thread.
87
88 // Thread execution sequence and actions:
89 // All threads:
90 // - thread_native_entry // per-OS native entry point
91 // - stack initialization
92 // - other OS-level initialization (signal masks etc)
93 // - handshake with creating thread (if not started suspended)
94 // - this->call_run() // common shared entry point
95 // - shared common initialization
96 // - this->pre_run() // virtual per-thread-type initialization
97 // - this->run() // virtual per-thread-type "main" logic
98 // - shared common tear-down
99 // - this->post_run() // virtual per-thread-type tear-down
100 // - // 'this' no longer referenceable
101 // - OS-level tear-down (minimal)
102 // - final logging
103 //
104 // For JavaThread:
105 // - this->run() // virtual but not normally overridden
106 // - this->thread_main_inner() // extra call level to ensure correct stack calculations
107 // - this->entry_point() // set differently for each kind of JavaThread
108
109 class Thread: public ThreadShadow {
110 friend class VMError;
111 friend class VMErrorCallbackMark;
112 friend class VMStructs;
113 friend class JVMCIVMStructs;
114 friend class JavaThread;
115 private:
116
117 // Current thread is maintained as a thread-local variable
118 static THREAD_LOCAL Thread* _thr_current;
119
120 // On AArch64, the high order 32 bits are used by a "patching epoch" number
121 // which reflects if this thread has executed the required fences, after
122 // an nmethod gets disarmed. The low order 32 bits denote the disarmed value.
123 uint64_t _nmethod_disarmed_guard_value;
124
125 public:
126 void set_nmethod_disarmed_guard_value(int value) {
127 _nmethod_disarmed_guard_value = (uint64_t)(uint32_t)value;
128 }
129
130 static ByteSize nmethod_disarmed_guard_value_offset() {
131 ByteSize offset = byte_offset_of(Thread, _nmethod_disarmed_guard_value);
132 // At least on x86_64, nmethod entry barrier encodes disarmed value offset
133 // in instruction as disp8 immed
134 assert(in_bytes(offset) < 128, "Offset >= 128");
135 return offset;
136 }
137
138 private:
139 // Poll data is used in generated code for safepoint polls.
140 // It is important for performance to put this at lower offset
141 // in Thread. The accessors are in JavaThread.
142 SafepointMechanism::ThreadData _poll_data;
143
144 // Thread local data area available to the GC. The internal
145 // structure and contents of this data area is GC-specific.
146 // Only GC and GC barrier code should access this data area.
147 GCThreadLocalData _gc_data;
148
149 public:
150 static ByteSize gc_data_offset() {
151 return byte_offset_of(Thread, _gc_data);
152 }
153
154 template <typename T> T* gc_data() {
155 STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
156 return reinterpret_cast<T*>(&_gc_data);
157 }
158
159 // Exception handling
160 // (Note: _pending_exception and friends are in ThreadShadow)
161 //oop _pending_exception; // pending exception for current thread
162 // const char* _exception_file; // file information for exception (debugging only)
163 // int _exception_line; // line information for exception (debugging only)
164 protected:
165 // JavaThread lifecycle support:
166 friend class SafeThreadsListPtr; // for _threads_list_ptr, cmpxchg_threads_hazard_ptr(), {dec_,inc_,}nested_threads_hazard_ptr_cnt(), {g,s}et_threads_hazard_ptr(), inc_nested_handle_cnt(), tag_hazard_ptr() access
167 friend class ScanHazardPtrGatherProtectedThreadsClosure; // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
168 friend class ScanHazardPtrGatherThreadsListClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access
169 friend class ScanHazardPtrPrintMatchingThreadsClosure; // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
170 friend class ThreadsSMRSupport; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
171 friend class ThreadsListHandleTest; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
172 friend class ValidateHazardPtrsClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access
173
174 ThreadsList* volatile _threads_hazard_ptr;
175 SafeThreadsListPtr* _threads_list_ptr;
176 ThreadsList* cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
177 ThreadsList* get_threads_hazard_ptr() const;
178 void set_threads_hazard_ptr(ThreadsList* new_list);
179 static bool is_hazard_ptr_tagged(ThreadsList* list) {
180 return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
181 }
182 static ThreadsList* tag_hazard_ptr(ThreadsList* list) {
183 return (ThreadsList*)(intptr_t(list) | intptr_t(1));
184 }
185 static ThreadsList* untag_hazard_ptr(ThreadsList* list) {
186 return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
187 }
188 // This field is enabled via -XX:+EnableThreadSMRStatistics:
189 uint _nested_threads_hazard_ptr_cnt;
190 void dec_nested_threads_hazard_ptr_cnt() {
191 assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
192 _nested_threads_hazard_ptr_cnt--;
193 }
194 void inc_nested_threads_hazard_ptr_cnt() {
195 _nested_threads_hazard_ptr_cnt++;
196 }
197 uint nested_threads_hazard_ptr_cnt() {
198 return _nested_threads_hazard_ptr_cnt;
199 }
200
201 public:
202 // Is the target JavaThread protected by the calling Thread or by some other
203 // mechanism?
204 static bool is_JavaThread_protected(const JavaThread* target);
205 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
206 // with the calling Thread?
207 static bool is_JavaThread_protected_by_TLH(const JavaThread* target);
208
209 private:
210 DEBUG_ONLY(static Thread* _starting_thread;)
211 DEBUG_ONLY(bool _suspendible_thread;)
212 DEBUG_ONLY(bool _indirectly_suspendible_thread;)
213 DEBUG_ONLY(bool _indirectly_safepoint_thread;)
214
215 public:
216 #ifdef ASSERT
217 static bool is_starting_thread(const Thread* t);
218
219 void set_suspendible_thread() { _suspendible_thread = true; }
220 void clear_suspendible_thread() { _suspendible_thread = false; }
221 bool is_suspendible_thread() { return _suspendible_thread; }
222
223 void set_indirectly_suspendible_thread() { _indirectly_suspendible_thread = true; }
224 void clear_indirectly_suspendible_thread() { _indirectly_suspendible_thread = false; }
225 bool is_indirectly_suspendible_thread() { return _indirectly_suspendible_thread; }
226
227 void set_indirectly_safepoint_thread() { _indirectly_safepoint_thread = true; }
228 void clear_indirectly_safepoint_thread() { _indirectly_safepoint_thread = false; }
229 bool is_indirectly_safepoint_thread() { return _indirectly_safepoint_thread; }
230 #endif
231
232 private:
233 // Point to the last handle mark
234 HandleMark* _last_handle_mark;
235
236 // Claim value for parallel iteration over threads.
237 uintx _threads_do_token;
238
239 // Support for GlobalCounter
240 private:
241 volatile uintx _rcu_counter;
242 public:
243 volatile uintx* get_rcu_counter() {
244 return &_rcu_counter;
245 }
246
247 public:
248 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; }
249 HandleMark* last_handle_mark() const { return _last_handle_mark; }
250
251 private:
252 // Used by SkipGCALot class.
253 NOT_PRODUCT(bool _skip_gcalot;) // Should we elide gc-a-lot?
254
255 friend class GCLocker;
256
257 private:
258 ThreadLocalAllocBuffer _tlab; // Thread-local eden
259 jlong _allocated_bytes; // Cumulative number of bytes allocated on
260 // the Java heap
261 ThreadHeapSampler _heap_sampler; // For use when sampling the memory.
262
263 ThreadStatisticalInfo _statistical_info; // Statistics about the thread
264
265 JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;) // Thread-local data for jfr
266
267 JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread
268 // is waiting to lock
269 public:
270 // Constructor
271 Thread(MemTag mem_tag = mtThread);
272 virtual ~Thread() = 0; // Thread is abstract.
273
274 // Manage Thread::current()
275 void initialize_thread_current();
276 static void clear_thread_current(); // TLS cleanup needed before threads terminate
277
278 protected:
279 // To be implemented by children.
280 virtual void run() = 0;
281 virtual void pre_run() = 0;
282 virtual void post_run() = 0; // Note: Thread must not be deleted prior to calling this!
283
284 #ifdef ASSERT
285 enum RunState {
286 PRE_CALL_RUN,
287 CALL_RUN,
288 PRE_RUN,
289 RUN,
290 POST_RUN
291 // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
292 };
293 RunState _run_state; // for lifecycle checks
294 #endif
295
296
297 public:
298 // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
299 void call_run();
300
301 // Testers
302 virtual bool is_VM_thread() const { return false; }
303 virtual bool is_Java_thread() const { return false; }
304 virtual bool is_Compiler_thread() const { return false; }
305 virtual bool is_service_thread() const { return false; }
306 virtual bool is_hidden_from_external_view() const { return false; }
307 virtual bool is_jvmti_agent_thread() const { return false; }
308 virtual bool is_Watcher_thread() const { return false; }
309 virtual bool is_ConcurrentGC_thread() const { return false; }
310 virtual bool is_Named_thread() const { return false; }
311 virtual bool is_Worker_thread() const { return false; }
312 virtual bool is_JfrSampler_thread() const { return false; }
313 virtual bool is_JfrRecorder_thread() const { return false; }
314 virtual bool is_AttachListener_thread() const { return false; }
315 virtual bool is_monitor_deflation_thread() const { return false; }
316 virtual bool is_aot_thread() const { return false; }
317
318 // Convenience cast functions
319 CompilerThread* as_Compiler_thread() const {
320 assert(is_Compiler_thread(), "Must be compiler thread");
321 return (CompilerThread*)this;
322 }
323
324 // Can this thread make Java upcalls
325 virtual bool can_call_java() const { return false; }
326
327 // Is this a JavaThread that is on the VM's current ThreadsList?
328 // If so it must participate in the safepoint protocol.
329 virtual bool is_active_Java_thread() const { return false; }
330
331 // All threads are given names. For singleton subclasses we can
332 // just hard-wire the known name of the instance. JavaThreads and
333 // NamedThreads support multiple named instances, and dynamic
334 // changing of the name of an instance.
335 virtual const char* name() const { return "Unknown thread"; }
336
337 // A thread's type name is also made available for debugging
338 // and logging.
339 virtual const char* type_name() const { return "Thread"; }
340
341 // Returns the current thread (ASSERTS if null)
342 static inline Thread* current();
343 // Returns the current thread, or null if not attached
344 static inline Thread* current_or_null();
345 // Returns the current thread, or null if not attached, and is
346 // safe for use from signal-handlers
347 static inline Thread* current_or_null_safe();
348
349 // Common thread operations
350 #ifdef ASSERT
351 static void check_for_dangling_thread_pointer(Thread *thread);
352 #endif
353 static void set_priority(Thread* thread, ThreadPriority priority);
354 static void start(Thread* thread);
355
356 void set_native_thread_name(const char *name) {
357 assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
358 os::set_native_thread_name(name);
359 }
360
361 // Support for Unhandled Oop detection
362 // Add the field for both, fastdebug and debug, builds to keep
363 // Thread's fields layout the same.
364 // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
365 #ifdef CHECK_UNHANDLED_OOPS
366 private:
367 UnhandledOops* _unhandled_oops;
368 #elif defined(ASSERT)
369 private:
370 void* _unhandled_oops;
371 #endif
372 #ifdef CHECK_UNHANDLED_OOPS
373 public:
374 UnhandledOops* unhandled_oops() { return _unhandled_oops; }
375 // Mark oop safe for gc. It may be stack allocated but won't move.
376 void allow_unhandled_oop(oop *op) {
377 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
378 }
379 // Clear oops at safepoint so crashes point to unhandled oop violator
380 void clear_unhandled_oops() {
381 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
382 }
383 #endif // CHECK_UNHANDLED_OOPS
384
385 public:
386 #ifndef PRODUCT
387 bool skip_gcalot() { return _skip_gcalot; }
388 void set_skip_gcalot(bool v) { _skip_gcalot = v; }
389 #endif
390
391 // Resource area
392 ResourceArea* resource_area() const { return _resource_area; }
393 void set_resource_area(ResourceArea* area) { _resource_area = area; }
394
395 OSThread* osthread() const { return _osthread; }
396 void set_osthread(OSThread* thread) { _osthread = thread; }
397
398 // Internal handle support
399 HandleArea* handle_area() const { return _handle_area; }
400 void set_handle_area(HandleArea* area) { _handle_area = area; }
401
402 GrowableArray<Metadata*>* metadata_handles() const { return _metadata_handles; }
403 void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
404
405 // Thread-Local Allocation Buffer (TLAB) support
406 ThreadLocalAllocBuffer& tlab() { return _tlab; }
407 void initialize_tlab();
408 void retire_tlab(ThreadLocalAllocStats* stats = nullptr);
409 void fill_tlab(HeapWord* start, size_t pre_reserved, size_t new_size);
410
411 jlong allocated_bytes() { return _allocated_bytes; }
412 void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
413 void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
414 inline jlong cooked_allocated_bytes();
415
416 ThreadHeapSampler& heap_sampler() { return _heap_sampler; }
417
418 ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
419
420 JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
421
422 // For tracking the Jvmti raw monitor the thread is pending on.
423 JvmtiRawMonitor* current_pending_raw_monitor() {
424 return _current_pending_raw_monitor;
425 }
426 void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) {
427 _current_pending_raw_monitor = monitor;
428 }
429
430 // GC support
431 // Apply "f->do_oop" to all root oops in "this".
432 // Used by JavaThread::oops_do.
433 // Apply "cf->do_nmethod" (if !nullptr) to all nmethods active in frames
434 virtual void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
435 virtual void oops_do_frames(OopClosure* f, NMethodClosure* cf) {}
436 void oops_do(OopClosure* f, NMethodClosure* cf);
437
438 // Handles the parallel case for claim_threads_do.
439 private:
440 bool claim_par_threads_do(uintx claim_token);
441 public:
442 // Requires that "claim_token" is that of the current iteration.
443 // If "is_par" is false, sets the token of "this" to
444 // "claim_token", and returns "true". If "is_par" is true,
445 // uses an atomic instruction to set the current thread's token to
446 // "claim_token", if it is not already. Returns "true" iff the
447 // calling thread does the update, this indicates that the calling thread
448 // has claimed the thread in the current iteration.
449 bool claim_threads_do(bool is_par, uintx claim_token) {
450 if (!is_par) {
451 _threads_do_token = claim_token;
452 return true;
453 } else {
454 return claim_par_threads_do(claim_token);
455 }
456 }
457
458 uintx threads_do_token() const { return _threads_do_token; }
459
460 // jvmtiRedefineClasses support
461 void metadata_handles_do(void f(Metadata*));
462
463 private:
464 // Check if address is within the given range of this thread's
465 // stack: stack_base() > adr >/>= limit
466 // The check is inclusive of limit if passed true, else exclusive.
467 bool is_in_stack_range(address adr, address limit, bool inclusive) const {
468 assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack");
469 return stack_base() > adr && (inclusive ? adr >= limit : adr > limit);
470 }
471
472 public:
473 // Check if address is within the given range of this thread's
474 // stack: stack_base() > adr >= limit
475 bool is_in_stack_range_incl(address adr, address limit) const {
476 return is_in_stack_range(adr, limit, true);
477 }
478
479 // Check if address is within the given range of this thread's
480 // stack: stack_base() > adr > limit
481 bool is_in_stack_range_excl(address adr, address limit) const {
482 return is_in_stack_range(adr, limit, false);
483 }
484
485 // Check if address is in the stack mapped to this thread. Used mainly in
486 // error reporting (so has to include guard zone) and frame printing.
487 // Expects _stack_base to be initialized - checked with assert.
488 bool is_in_full_stack_checked(address adr) const {
489 return is_in_stack_range_incl(adr, stack_end());
490 }
491
492 // Like is_in_full_stack_checked but without the assertions as this
493 // may be called in a thread before _stack_base is initialized.
494 bool is_in_full_stack(address adr) const {
495 address stack_end = _stack_base - _stack_size;
496 return _stack_base > adr && adr >= stack_end;
497 }
498
499 // Check if address is in the live stack of this thread (not just for locks).
500 // Warning: can only be called by the current thread on itself.
501 bool is_in_live_stack(address adr) const {
502 assert(Thread::current() == this, "is_in_live_stack can only be called from current thread");
503 return is_in_stack_range_incl(adr, os::current_stack_pointer());
504 }
505
506 // Sets the argument thread as starting thread. Returns failure if thread
507 // creation fails due to lack of memory, too many threads etc.
508 static bool set_as_starting_thread(JavaThread* jt);
509
510 protected:
511 // OS data associated with the thread
512 OSThread* _osthread; // Platform-specific thread information
513
514 // Thread local resource area for temporary allocation within the VM
515 ResourceArea* _resource_area;
516
517 DEBUG_ONLY(ResourceMark* _current_resource_mark;)
518
519 // Thread local handle area for allocation of handles within the VM
520 HandleArea* _handle_area;
521 GrowableArray<Metadata*>* _metadata_handles;
522
523 // Support for stack overflow handling, get_thread, etc.
524 address _stack_base;
525 size_t _stack_size;
526
527 public:
528 // Stack overflow support
529 address stack_base() const DEBUG_ONLY(;) NOT_DEBUG({ return _stack_base; })
530 // Needed for code that can query a new thread before the stack has been set.
531 address stack_base_or_null() const { return _stack_base; }
532 void set_stack_base(address base) { _stack_base = base; }
533 size_t stack_size() const { return _stack_size; }
534 void set_stack_size(size_t size) { _stack_size = size; }
535 address stack_end() const { return stack_base() - stack_size(); }
536 void record_stack_base_and_size();
537 void register_thread_stack_with_NMT();
538 void unregister_thread_stack_with_NMT();
539
540 // Printing
541 void print_on(outputStream* st, bool print_extended_info) const;
542 virtual void print_on(outputStream* st) const { print_on(st, false); }
543 void print() const;
544 virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
545 // Basic, non-virtual, printing support that is simple and always safe.
546 void print_value_on(outputStream* st) const;
547
548 // Debug-only code
549 #ifdef ASSERT
550 private:
551 // Deadlock detection support for Mutex locks. List of locks own by thread.
552 Mutex* _owned_locks;
553 // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
554 // thus the friendship
555 friend class Mutex;
556 friend class Monitor;
557
558 public:
559 void print_owned_locks_on(outputStream* st) const;
560 void print_owned_locks() const { print_owned_locks_on(tty); }
561 Mutex* owned_locks() const { return _owned_locks; }
562 bool owns_locks() const { return owned_locks() != nullptr; }
563
564 // Deadlock detection
565 ResourceMark* current_resource_mark() { return _current_resource_mark; }
566 void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
567 #endif // ASSERT
568
569 private:
570 volatile int _jvmti_env_iteration_count;
571
572 public:
573 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; }
574 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; }
575 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; }
576
577 // Code generation
578 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file); }
579 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line); }
580
581 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base); }
582 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size); }
583
584 static ByteSize tlab_start_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
585 static ByteSize tlab_end_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
586 static ByteSize tlab_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
587 static ByteSize tlab_pf_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
588
589 JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
590
591 public:
592 ParkEvent * volatile _ParkEvent; // for Object monitors, JVMTI raw monitors,
593 // and ObjectSynchronizer::read_stable_mark
594
595 // Termination indicator used by the signal handler.
596 // _ParkEvent is just a convenient field we can null out after setting the JavaThread termination state
597 // (which can't itself be read from the signal handler if a signal hits during the Thread destructor).
598 bool has_terminated() { return AtomicAccess::load(&_ParkEvent) == nullptr; };
599
600 jint _hashStateW; // Marsaglia Shift-XOR thread-local RNG
601 jint _hashStateX; // thread-specific hashCode generator state
602 jint _hashStateY;
603 jint _hashStateZ;
604
605 // Low-level leaf-lock primitives used to implement synchronization.
606 // Not for general synchronization use.
607 static void SpinAcquire(volatile int * Lock);
608 static void SpinRelease(volatile int * Lock);
609
610 #if defined(__APPLE__) && defined(AARCH64)
611 private:
612 DEBUG_ONLY(bool _wx_init);
613 WXMode _wx_state;
614 public:
615 void init_wx();
616 WXMode enable_wx(WXMode new_state);
617
618 void assert_wx_state(WXMode expected) {
619 assert(_wx_state == expected, "wrong state");
620 }
621 #endif // __APPLE__ && AARCH64
622
623 private:
624 bool _in_asgct = false;
625 public:
626 bool in_asgct() const { return _in_asgct; }
627 void set_in_asgct(bool value) { _in_asgct = value; }
628 static bool current_in_asgct() {
629 Thread *cur = Thread::current_or_null_safe();
630 return cur != nullptr && cur->in_asgct();
631 }
632
633 private:
634 VMErrorCallback* _vm_error_callbacks;
635 };
636
637 class ThreadInAsgct {
638 private:
639 Thread* _thread;
640 bool _saved_in_asgct;
641 public:
642 ThreadInAsgct(Thread* thread) : _thread(thread) {
643 assert(thread != nullptr, "invariant");
644 // Allow AsyncGetCallTrace to be reentrant - save the previous state.
645 _saved_in_asgct = thread->in_asgct();
646 thread->set_in_asgct(true);
647 }
648 ~ThreadInAsgct() {
649 assert(_thread->in_asgct(), "invariant");
650 _thread->set_in_asgct(_saved_in_asgct);
651 }
652 };
653
654 // Inline implementation of Thread::current()
655 inline Thread* Thread::current() {
656 Thread* current = current_or_null();
657 assert(current != nullptr, "Thread::current() called on detached thread");
658 return current;
659 }
660
661 inline Thread* Thread::current_or_null() {
662 return _thr_current;
663 }
664
665 inline Thread* Thread::current_or_null_safe() {
666 if (ThreadLocalStorage::is_initialized()) {
667 return ThreadLocalStorage::thread();
668 }
669 return nullptr;
670 }
671
672 #endif // SHARE_RUNTIME_THREAD_HPP