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_THREAD_HPP
27 #define SHARE_RUNTIME_THREAD_HPP
28
29 #include "jni.h"
30 #include "gc/shared/gcThreadLocalData.hpp"
31 #include "gc/shared/threadLocalAllocBuffer.hpp"
32 #include "memory/allocation.hpp"
33 #include "runtime/atomic.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 // - LogAsyncWriter
82 //
83 // All Thread subclasses must be either JavaThread or NonJavaThread.
84 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
85 // a partially constructed/destroyed Thread.
86
87 // Thread execution sequence and actions:
88 // All threads:
89 // - thread_native_entry // per-OS native entry point
90 // - stack initialization
91 // - other OS-level initialization (signal masks etc)
92 // - handshake with creating thread (if not started suspended)
93 // - this->call_run() // common shared entry point
94 // - shared common initialization
95 // - this->pre_run() // virtual per-thread-type initialization
96 // - this->run() // virtual per-thread-type "main" logic
97 // - shared common tear-down
98 // - this->post_run() // virtual per-thread-type tear-down
99 // - // 'this' no longer referenceable
100 // - OS-level tear-down (minimal)
101 // - final logging
102 //
103 // For JavaThread:
104 // - this->run() // virtual but not normally overridden
105 // - this->thread_main_inner() // extra call level to ensure correct stack calculations
106 // - this->entry_point() // set differently for each kind of JavaThread
107
108 class Thread: public ThreadShadow {
109 friend class VMError;
110 friend class VMErrorCallbackMark;
111 friend class VMStructs;
112 friend class JVMCIVMStructs;
113 friend class JavaThread;
114 private:
115
116 #ifndef USE_LIBRARY_BASED_TLS_ONLY
117 // Current thread is maintained as a thread-local variable
118 static THREAD_LOCAL Thread* _thr_current;
119 #endif
120
121 // On AArch64, the high order 32 bits are used by a "patching epoch" number
122 // which reflects if this thread has executed the required fences, after
123 // an nmethod gets disarmed. The low order 32 bits denote the disarmed value.
124 uint64_t _nmethod_disarmed_guard_value;
125
126 public:
127 void set_nmethod_disarmed_guard_value(int value) {
128 _nmethod_disarmed_guard_value = (uint64_t)(uint32_t)value;
129 }
130
131 static ByteSize nmethod_disarmed_guard_value_offset() {
132 ByteSize offset = byte_offset_of(Thread, _nmethod_disarmed_guard_value);
133 // At least on x86_64, nmethod entry barrier encodes disarmed value offset
134 // in instruction as disp8 immed
135 assert(in_bytes(offset) < 128, "Offset >= 128");
136 return offset;
137 }
138
139 private:
140 // Poll data is used in generated code for safepoint polls.
141 // It is important for performance to put this at lower offset
142 // in Thread. The accessors are in JavaThread.
143 SafepointMechanism::ThreadData _poll_data;
144
145 // Thread local data area available to the GC. The internal
146 // structure and contents of this data area is GC-specific.
147 // Only GC and GC barrier code should access this data area.
148 GCThreadLocalData _gc_data;
149
150 public:
151 static ByteSize gc_data_offset() {
152 return byte_offset_of(Thread, _gc_data);
153 }
154
155 template <typename T> T* gc_data() {
156 STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
157 return reinterpret_cast<T*>(&_gc_data);
158 }
159
160 // Exception handling
161 // (Note: _pending_exception and friends are in ThreadShadow)
162 //oop _pending_exception; // pending exception for current thread
163 // const char* _exception_file; // file information for exception (debugging only)
164 // int _exception_line; // line information for exception (debugging only)
165 protected:
166 // JavaThread lifecycle support:
167 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
168 friend class ScanHazardPtrGatherProtectedThreadsClosure; // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
169 friend class ScanHazardPtrGatherThreadsListClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access
170 friend class ScanHazardPtrPrintMatchingThreadsClosure; // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
171 friend class ThreadsSMRSupport; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
172 friend class ThreadsListHandleTest; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
173 friend class ValidateHazardPtrsClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access
174
175 ThreadsList* volatile _threads_hazard_ptr;
176 SafeThreadsListPtr* _threads_list_ptr;
177 ThreadsList* cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
178 ThreadsList* get_threads_hazard_ptr() const;
179 void set_threads_hazard_ptr(ThreadsList* new_list);
180 static bool is_hazard_ptr_tagged(ThreadsList* list) {
181 return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
182 }
183 static ThreadsList* tag_hazard_ptr(ThreadsList* list) {
184 return (ThreadsList*)(intptr_t(list) | intptr_t(1));
185 }
186 static ThreadsList* untag_hazard_ptr(ThreadsList* list) {
187 return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
188 }
189 // This field is enabled via -XX:+EnableThreadSMRStatistics:
190 uint _nested_threads_hazard_ptr_cnt;
191 void dec_nested_threads_hazard_ptr_cnt() {
192 assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
193 _nested_threads_hazard_ptr_cnt--;
194 }
195 void inc_nested_threads_hazard_ptr_cnt() {
196 _nested_threads_hazard_ptr_cnt++;
197 }
198 uint nested_threads_hazard_ptr_cnt() {
199 return _nested_threads_hazard_ptr_cnt;
200 }
201
202 public:
203 // Is the target JavaThread protected by the calling Thread or by some other
204 // mechanism?
205 static bool is_JavaThread_protected(const JavaThread* target);
206 // Is the target JavaThread protected by a ThreadsListHandle (TLH) associated
207 // with the calling Thread?
208 static bool is_JavaThread_protected_by_TLH(const JavaThread* target);
209
210 private:
211 DEBUG_ONLY(static Thread* _starting_thread;)
212 DEBUG_ONLY(bool _suspendible_thread;)
213 DEBUG_ONLY(bool _indirectly_suspendible_thread;)
214 DEBUG_ONLY(bool _indirectly_safepoint_thread;)
215
216 public:
217 #ifdef ASSERT
218 static bool is_starting_thread(const Thread* t);
219
220 void set_suspendible_thread() { _suspendible_thread = true; }
221 void clear_suspendible_thread() { _suspendible_thread = false; }
222 bool is_suspendible_thread() { return _suspendible_thread; }
223
224 void set_indirectly_suspendible_thread() { _indirectly_suspendible_thread = true; }
225 void clear_indirectly_suspendible_thread() { _indirectly_suspendible_thread = false; }
226 bool is_indirectly_suspendible_thread() { return _indirectly_suspendible_thread; }
227
228 void set_indirectly_safepoint_thread() { _indirectly_safepoint_thread = true; }
229 void clear_indirectly_safepoint_thread() { _indirectly_safepoint_thread = false; }
230 bool is_indirectly_safepoint_thread() { return _indirectly_safepoint_thread; }
231 #endif
232
233 private:
234 // Point to the last handle mark
235 HandleMark* _last_handle_mark;
236
237 // Claim value for parallel iteration over threads.
238 uintx _threads_do_token;
239
240 // Support for GlobalCounter
241 private:
242 volatile uintx _rcu_counter;
243 public:
244 volatile uintx* get_rcu_counter() {
245 return &_rcu_counter;
246 }
247
248 public:
249 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; }
250 HandleMark* last_handle_mark() const { return _last_handle_mark; }
251
252 private:
253 // Used by SkipGCALot class.
254 NOT_PRODUCT(bool _skip_gcalot;) // Should we elide gc-a-lot?
255
256 friend class GCLocker;
257
258 private:
259 ThreadLocalAllocBuffer _tlab; // Thread-local eden
260 jlong _allocated_bytes; // Cumulative number of bytes allocated on
261 // the Java heap
262 ThreadHeapSampler _heap_sampler; // For use when sampling the memory.
263
264 ThreadStatisticalInfo _statistical_info; // Statistics about the thread
265
266 JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;) // Thread-local data for jfr
267
268 JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread
269 // is waiting to lock
270 public:
271 // Constructor
272 Thread(MemTag mem_tag = mtThread);
273 virtual ~Thread() = 0; // Thread is abstract.
274
275 // Manage Thread::current()
276 void initialize_thread_current();
277 static void clear_thread_current(); // TLS cleanup needed before threads terminate
278
279 protected:
280 // To be implemented by children.
281 virtual void run() = 0;
282 virtual void pre_run() = 0;
283 virtual void post_run() = 0; // Note: Thread must not be deleted prior to calling this!
284
285 #ifdef ASSERT
286 enum RunState {
287 PRE_CALL_RUN,
288 CALL_RUN,
289 PRE_RUN,
290 RUN,
291 POST_RUN
292 // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
293 };
294 RunState _run_state; // for lifecycle checks
295 #endif
296
297
298 public:
299 // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
300 void call_run();
301
302 // Testers
303 virtual bool is_VM_thread() const { return false; }
304 virtual bool is_Java_thread() const { return false; }
305 virtual bool is_Compiler_thread() const { return false; }
306 virtual bool is_service_thread() const { return false; }
307 virtual bool is_hidden_from_external_view() const { return false; }
308 virtual bool is_jvmti_agent_thread() const { return false; }
309 virtual bool is_Watcher_thread() const { return false; }
310 virtual bool is_ConcurrentGC_thread() const { return false; }
311 virtual bool is_Named_thread() const { return false; }
312 virtual bool is_Worker_thread() const { return false; }
313 virtual bool is_JfrSampler_thread() const { return false; }
314 virtual bool is_AttachListener_thread() const { return false; }
315 virtual bool is_monitor_deflation_thread() const { return false; }
316
317 // Convenience cast functions
318 CompilerThread* as_Compiler_thread() const {
319 assert(is_Compiler_thread(), "Must be compiler thread");
320 return (CompilerThread*)this;
321 }
322
323 // Can this thread make Java upcalls
324 virtual bool can_call_java() const { return false; }
325
326 // Is this a JavaThread that is on the VM's current ThreadsList?
327 // If so it must participate in the safepoint protocol.
328 virtual bool is_active_Java_thread() const { return false; }
329
330 // All threads are given names. For singleton subclasses we can
331 // just hard-wire the known name of the instance. JavaThreads and
332 // NamedThreads support multiple named instances, and dynamic
333 // changing of the name of an instance.
334 virtual const char* name() const { return "Unknown thread"; }
335
336 // A thread's type name is also made available for debugging
337 // and logging.
338 virtual const char* type_name() const { return "Thread"; }
339
340 // Returns the current thread (ASSERTS if null)
341 static inline Thread* current();
342 // Returns the current thread, or null if not attached
343 static inline Thread* current_or_null();
344 // Returns the current thread, or null if not attached, and is
345 // safe for use from signal-handlers
346 static inline Thread* current_or_null_safe();
347
348 // Common thread operations
349 #ifdef ASSERT
350 static void check_for_dangling_thread_pointer(Thread *thread);
351 #endif
352 static void set_priority(Thread* thread, ThreadPriority priority);
353 static void start(Thread* thread);
354
355 void set_native_thread_name(const char *name) {
356 assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
357 os::set_native_thread_name(name);
358 }
359
360 // Support for Unhandled Oop detection
361 // Add the field for both, fastdebug and debug, builds to keep
362 // Thread's fields layout the same.
363 // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
364 #ifdef CHECK_UNHANDLED_OOPS
365 private:
366 UnhandledOops* _unhandled_oops;
367 #elif defined(ASSERT)
368 private:
369 void* _unhandled_oops;
370 #endif
371 #ifdef CHECK_UNHANDLED_OOPS
372 public:
373 UnhandledOops* unhandled_oops() { return _unhandled_oops; }
374 // Mark oop safe for gc. It may be stack allocated but won't move.
375 void allow_unhandled_oop(oop *op) {
376 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
377 }
378 // Clear oops at safepoint so crashes point to unhandled oop violator
379 void clear_unhandled_oops() {
380 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
381 }
382 #endif // CHECK_UNHANDLED_OOPS
383
384 public:
385 #ifndef PRODUCT
386 bool skip_gcalot() { return _skip_gcalot; }
387 void set_skip_gcalot(bool v) { _skip_gcalot = v; }
388 #endif
389
390 // Resource area
391 ResourceArea* resource_area() const { return _resource_area; }
392 void set_resource_area(ResourceArea* area) { _resource_area = area; }
393
394 OSThread* osthread() const { return _osthread; }
395 void set_osthread(OSThread* thread) { _osthread = thread; }
396
397 // Internal handle support
398 HandleArea* handle_area() const { return _handle_area; }
399 void set_handle_area(HandleArea* area) { _handle_area = area; }
400
401 GrowableArray<Metadata*>* metadata_handles() const { return _metadata_handles; }
402 void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
403
404 // Thread-Local Allocation Buffer (TLAB) support
405 ThreadLocalAllocBuffer& tlab() { return _tlab; }
406 void initialize_tlab();
407
408 jlong allocated_bytes() { return _allocated_bytes; }
409 void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
410 void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
411 inline jlong cooked_allocated_bytes();
412
413 ThreadHeapSampler& heap_sampler() { return _heap_sampler; }
414
415 ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
416
417 JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
418
419 // For tracking the Jvmti raw monitor the thread is pending on.
420 JvmtiRawMonitor* current_pending_raw_monitor() {
421 return _current_pending_raw_monitor;
422 }
423 void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) {
424 _current_pending_raw_monitor = monitor;
425 }
426
427 // GC support
428 // Apply "f->do_oop" to all root oops in "this".
429 // Used by JavaThread::oops_do.
430 // Apply "cf->do_nmethod" (if !nullptr) to all nmethods active in frames
431 virtual void oops_do_no_frames(OopClosure* f, NMethodClosure* cf);
432 virtual void oops_do_frames(OopClosure* f, NMethodClosure* cf) {}
433 void oops_do(OopClosure* f, NMethodClosure* cf);
434
435 // Handles the parallel case for claim_threads_do.
436 private:
437 bool claim_par_threads_do(uintx claim_token);
438 public:
439 // Requires that "claim_token" is that of the current iteration.
440 // If "is_par" is false, sets the token of "this" to
441 // "claim_token", and returns "true". If "is_par" is true,
442 // uses an atomic instruction to set the current thread's token to
443 // "claim_token", if it is not already. Returns "true" iff the
444 // calling thread does the update, this indicates that the calling thread
445 // has claimed the thread in the current iteration.
446 bool claim_threads_do(bool is_par, uintx claim_token) {
447 if (!is_par) {
448 _threads_do_token = claim_token;
449 return true;
450 } else {
451 return claim_par_threads_do(claim_token);
452 }
453 }
454
455 uintx threads_do_token() const { return _threads_do_token; }
456
457 // jvmtiRedefineClasses support
458 void metadata_handles_do(void f(Metadata*));
459
460 private:
461 // Check if address is within the given range of this thread's
462 // stack: stack_base() > adr >/>= limit
463 // The check is inclusive of limit if passed true, else exclusive.
464 bool is_in_stack_range(address adr, address limit, bool inclusive) const {
465 assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack");
466 return stack_base() > adr && (inclusive ? adr >= limit : adr > limit);
467 }
468
469 public:
470 // Check if address is within the given range of this thread's
471 // stack: stack_base() > adr >= limit
472 bool is_in_stack_range_incl(address adr, address limit) const {
473 return is_in_stack_range(adr, limit, true);
474 }
475
476 // Check if address is within the given range of this thread's
477 // stack: stack_base() > adr > limit
478 bool is_in_stack_range_excl(address adr, address limit) const {
479 return is_in_stack_range(adr, limit, false);
480 }
481
482 // Check if address is in the stack mapped to this thread. Used mainly in
483 // error reporting (so has to include guard zone) and frame printing.
484 // Expects _stack_base to be initialized - checked with assert.
485 bool is_in_full_stack_checked(address adr) const {
486 return is_in_stack_range_incl(adr, stack_end());
487 }
488
489 // Like is_in_full_stack_checked but without the assertions as this
490 // may be called in a thread before _stack_base is initialized.
491 bool is_in_full_stack(address adr) const {
492 address stack_end = _stack_base - _stack_size;
493 return _stack_base > adr && adr >= stack_end;
494 }
495
496 // Check if address is in the live stack of this thread (not just for locks).
497 // Warning: can only be called by the current thread on itself.
498 bool is_in_live_stack(address adr) const {
499 assert(Thread::current() == this, "is_in_live_stack can only be called from current thread");
500 return is_in_stack_range_incl(adr, os::current_stack_pointer());
501 }
502
503 // Sets the argument thread as starting thread. Returns failure if thread
504 // creation fails due to lack of memory, too many threads etc.
505 static bool set_as_starting_thread(JavaThread* jt);
506
507 protected:
508 // OS data associated with the thread
509 OSThread* _osthread; // Platform-specific thread information
510
511 // Thread local resource area for temporary allocation within the VM
512 ResourceArea* _resource_area;
513
514 DEBUG_ONLY(ResourceMark* _current_resource_mark;)
515
516 // Thread local handle area for allocation of handles within the VM
517 HandleArea* _handle_area;
518 GrowableArray<Metadata*>* _metadata_handles;
519
520 // Support for stack overflow handling, get_thread, etc.
521 address _stack_base;
522 size_t _stack_size;
523 int _lgrp_id;
524
525 public:
526 // Stack overflow support
527 address stack_base() const DEBUG_ONLY(;) NOT_DEBUG({ return _stack_base; })
528 void set_stack_base(address base) { _stack_base = base; }
529 size_t stack_size() const { return _stack_size; }
530 void set_stack_size(size_t size) { _stack_size = size; }
531 address stack_end() const { return stack_base() - stack_size(); }
532 void record_stack_base_and_size();
533 void register_thread_stack_with_NMT();
534 void unregister_thread_stack_with_NMT();
535
536 int lgrp_id() const { return _lgrp_id; }
537 void set_lgrp_id(int value) { _lgrp_id = value; }
538
539 // Printing
540 void print_on(outputStream* st, bool print_extended_info) const;
541 virtual void print_on(outputStream* st) const { print_on(st, false); }
542 void print() const;
543 virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
544 // Basic, non-virtual, printing support that is simple and always safe.
545 void print_value_on(outputStream* st) const;
546
547 // Debug-only code
548 #ifdef ASSERT
549 private:
550 // Deadlock detection support for Mutex locks. List of locks own by thread.
551 Mutex* _owned_locks;
552 // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
553 // thus the friendship
554 friend class Mutex;
555 friend class Monitor;
556
557 public:
558 void print_owned_locks_on(outputStream* st) const;
559 void print_owned_locks() const { print_owned_locks_on(tty); }
560 Mutex* owned_locks() const { return _owned_locks; }
561 bool owns_locks() const { return owned_locks() != nullptr; }
562
563 // Deadlock detection
564 ResourceMark* current_resource_mark() { return _current_resource_mark; }
565 void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
566 #endif // ASSERT
567
568 private:
569 volatile int _jvmti_env_iteration_count;
570
571 public:
572 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; }
573 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; }
574 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; }
575
576 // Code generation
577 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file); }
578 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line); }
579
580 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base); }
581 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size); }
582
583 static ByteSize tlab_start_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
584 static ByteSize tlab_end_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
585 static ByteSize tlab_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
586 static ByteSize tlab_pf_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
587
588 JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
589
590 public:
591 ParkEvent * volatile _ParkEvent; // for Object monitors, JVMTI raw monitors,
592 // and ObjectSynchronizer::read_stable_mark
593
594 // Termination indicator used by the signal handler.
595 // _ParkEvent is just a convenient field we can null out after setting the JavaThread termination state
596 // (which can't itself be read from the signal handler if a signal hits during the Thread destructor).
597 bool has_terminated() { return Atomic::load(&_ParkEvent) == nullptr; };
598
599 jint _hashStateW; // Marsaglia Shift-XOR thread-local RNG
600 jint _hashStateX; // thread-specific hashCode generator state
601 jint _hashStateY;
602 jint _hashStateZ;
603
604 // Low-level leaf-lock primitives used to implement synchronization.
605 // Not for general synchronization use.
606 static void SpinAcquire(volatile int * Lock, const char * Name);
607 static void SpinRelease(volatile int * Lock);
608
609 #if defined(__APPLE__) && defined(AARCH64)
610 private:
611 DEBUG_ONLY(bool _wx_init);
612 WXMode _wx_state;
613 public:
614 void init_wx();
615 WXMode enable_wx(WXMode new_state);
616
617 void assert_wx_state(WXMode expected) {
618 assert(_wx_state == expected, "wrong state");
619 }
620 #endif // __APPLE__ && AARCH64
621
622 private:
623 bool _in_asgct = false;
624 public:
625 bool in_asgct() const { return _in_asgct; }
626 void set_in_asgct(bool value) { _in_asgct = value; }
627 static bool current_in_asgct() {
628 Thread *cur = Thread::current_or_null_safe();
629 return cur != nullptr && cur->in_asgct();
630 }
631
632 private:
633 VMErrorCallback* _vm_error_callbacks;
634 };
635
636 class ThreadInAsgct {
637 private:
638 Thread* _thread;
639 bool _saved_in_asgct;
640 public:
641 ThreadInAsgct(Thread* thread) : _thread(thread) {
642 assert(thread != nullptr, "invariant");
643 // Allow AsyncGetCallTrace to be reentrant - save the previous state.
644 _saved_in_asgct = thread->in_asgct();
645 thread->set_in_asgct(true);
646 }
647 ~ThreadInAsgct() {
648 assert(_thread->in_asgct(), "invariant");
649 _thread->set_in_asgct(_saved_in_asgct);
650 }
651 };
652
653 // Inline implementation of Thread::current()
654 inline Thread* Thread::current() {
655 Thread* current = current_or_null();
656 assert(current != nullptr, "Thread::current() called on detached thread");
657 return current;
658 }
659
660 inline Thread* Thread::current_or_null() {
661 #ifndef USE_LIBRARY_BASED_TLS_ONLY
662 return _thr_current;
663 #else
664 if (ThreadLocalStorage::is_initialized()) {
665 return ThreadLocalStorage::thread();
666 }
667 return nullptr;
668 #endif
669 }
670
671 inline Thread* Thread::current_or_null_safe() {
672 if (ThreadLocalStorage::is_initialized()) {
673 return ThreadLocalStorage::thread();
674 }
675 return nullptr;
676 }
677
678 #endif // SHARE_RUNTIME_THREAD_HPP