1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_RUNTIME_THREAD_HPP
26 #define SHARE_RUNTIME_THREAD_HPP
27
28 #include "jni.h"
29 #include "gc/shared/gcThreadLocalData.hpp"
30 #include "gc/shared/threadLocalAllocBuffer.hpp"
31 #include "memory/allocation.hpp"
32 #include "oops/oop.hpp"
33 #include "prims/jvmtiExport.hpp"
34 #include "runtime/frame.hpp"
35 #include "runtime/globals.hpp"
36 #include "runtime/handshake.hpp"
37 #include "runtime/javaFrameAnchor.hpp"
38 #include "runtime/jniHandles.hpp"
39 #include "runtime/mutexLocker.hpp"
40 #include "runtime/os.hpp"
41 #include "runtime/osThread.hpp"
42 #include "runtime/park.hpp"
43 #include "runtime/stubRoutines.hpp"
44 #include "runtime/threadHeapSampler.hpp"
45 #include "runtime/threadLocalStorage.hpp"
46 #include "runtime/threadStatisticalInfo.hpp"
47 #include "runtime/unhandledOops.hpp"
48 #include "utilities/align.hpp"
49 #include "utilities/exceptions.hpp"
50 #include "utilities/globalDefinitions.hpp"
51 #include "utilities/macros.hpp"
52 #if INCLUDE_JFR
53 #include "jfr/support/jfrThreadExtension.hpp"
54 #endif
55
56
57 class SafeThreadsListPtr;
58 class ThreadSafepointState;
59 class ThreadsList;
60 class ThreadsSMRSupport;
61
62 class JvmtiRawMonitor;
63 class JvmtiThreadState;
64 class ThreadStatistics;
65 class ConcurrentLocksDump;
66 class ParkEvent;
67 class Parker;
68 class MonitorInfo;
69
70 class AbstractCompiler;
71 class ciEnv;
72 class CompileThread;
73 class CompileLog;
74 class CompileTask;
75 class CompileQueue;
76 class CompilerCounters;
77
78 class vframeArray;
79 class vframe;
80 class javaVFrame;
81
82 class DeoptResourceMark;
83 class jvmtiDeferredLocalVariableSet;
84
85 class ThreadClosure;
86 class ICRefillVerifier;
87 class IdealGraphPrinter;
88
89 class JVMCIEnv;
90 class JVMCIPrimitiveArray;
91
92 class Metadata;
93 class ResourceArea;
94
95 class OopStorage;
96
97 DEBUG_ONLY(class ResourceMark;)
98
99 class WorkerThread;
100
101 // Class hierarchy
102 // - Thread
103 // - JavaThread
104 // - various subclasses eg CompilerThread, ServiceThread
105 // - NonJavaThread
106 // - NamedThread
107 // - VMThread
108 // - ConcurrentGCThread
109 // - WorkerThread
110 // - GangWorker
111 // - WatcherThread
112 // - JfrThreadSampler
113 //
114 // All Thread subclasses must be either JavaThread or NonJavaThread.
115 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is
116 // a partially constructed/destroyed Thread.
117
118 // Thread execution sequence and actions:
119 // All threads:
120 // - thread_native_entry // per-OS native entry point
121 // - stack initialization
122 // - other OS-level initialization (signal masks etc)
123 // - handshake with creating thread (if not started suspended)
124 // - this->call_run() // common shared entry point
125 // - shared common initialization
126 // - this->pre_run() // virtual per-thread-type initialization
127 // - this->run() // virtual per-thread-type "main" logic
128 // - shared common tear-down
129 // - this->post_run() // virtual per-thread-type tear-down
130 // - // 'this' no longer referenceable
131 // - OS-level tear-down (minimal)
132 // - final logging
133 //
134 // For JavaThread:
135 // - this->run() // virtual but not normally overridden
136 // - this->thread_main_inner() // extra call level to ensure correct stack calculations
137 // - this->entry_point() // set differently for each kind of JavaThread
138
139 class Thread: public ThreadShadow {
140 friend class VMStructs;
141 friend class JVMCIVMStructs;
142 private:
143
144 #ifndef USE_LIBRARY_BASED_TLS_ONLY
145 // Current thread is maintained as a thread-local variable
146 static THREAD_LOCAL Thread* _thr_current;
147 #endif
148
149 // Thread local data area available to the GC. The internal
150 // structure and contents of this data area is GC-specific.
151 // Only GC and GC barrier code should access this data area.
152 GCThreadLocalData _gc_data;
153
154 public:
155 static ByteSize gc_data_offset() {
156 return byte_offset_of(Thread, _gc_data);
157 }
158
159 template <typename T> T* gc_data() {
160 STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data));
161 return reinterpret_cast<T*>(&_gc_data);
162 }
163
164 // Exception handling
165 // (Note: _pending_exception and friends are in ThreadShadow)
166 //oop _pending_exception; // pending exception for current thread
167 // const char* _exception_file; // file information for exception (debugging only)
168 // int _exception_line; // line information for exception (debugging only)
169 protected:
170
171 DEBUG_ONLY(static Thread* _starting_thread;)
172
173 // Support for forcing alignment of thread objects for biased locking
174 void* _real_malloc_address;
175
176 // JavaThread lifecycle support:
177 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
178 friend class ScanHazardPtrGatherProtectedThreadsClosure; // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
179 friend class ScanHazardPtrGatherThreadsListClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access
180 friend class ScanHazardPtrPrintMatchingThreadsClosure; // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access
181 friend class ThreadsSMRSupport; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access
182
183 ThreadsList* volatile _threads_hazard_ptr;
184 SafeThreadsListPtr* _threads_list_ptr;
185 ThreadsList* cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value);
186 ThreadsList* get_threads_hazard_ptr();
187 void set_threads_hazard_ptr(ThreadsList* new_list);
188 static bool is_hazard_ptr_tagged(ThreadsList* list) {
189 return (intptr_t(list) & intptr_t(1)) == intptr_t(1);
190 }
191 static ThreadsList* tag_hazard_ptr(ThreadsList* list) {
192 return (ThreadsList*)(intptr_t(list) | intptr_t(1));
193 }
194 static ThreadsList* untag_hazard_ptr(ThreadsList* list) {
195 return (ThreadsList*)(intptr_t(list) & ~intptr_t(1));
196 }
197 // This field is enabled via -XX:+EnableThreadSMRStatistics:
198 uint _nested_threads_hazard_ptr_cnt;
199 void dec_nested_threads_hazard_ptr_cnt() {
200 assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()");
201 _nested_threads_hazard_ptr_cnt--;
202 }
203 void inc_nested_threads_hazard_ptr_cnt() {
204 _nested_threads_hazard_ptr_cnt++;
205 }
206 uint nested_threads_hazard_ptr_cnt() {
207 return _nested_threads_hazard_ptr_cnt;
208 }
209
210 public:
211 void* operator new(size_t size) throw() { return allocate(size, true); }
212 void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
213 return allocate(size, false); }
214 void operator delete(void* p);
215
216 protected:
217 static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread);
218 private:
219
220 // ***************************************************************
221 // Suspend and resume support
222 // ***************************************************************
223 //
224 // VM suspend/resume no longer exists - it was once used for various
225 // things including safepoints but was deprecated and finally removed
226 // in Java 7. Because VM suspension was considered "internal" Java-level
227 // suspension was considered "external", and this legacy naming scheme
228 // remains.
229 //
230 // External suspend/resume requests come from JVM_SuspendThread,
231 // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI
232 // ResumeThread. External
233 // suspend requests cause _external_suspend to be set and external
234 // resume requests cause _external_suspend to be cleared.
235 // External suspend requests do not nest on top of other external
236 // suspend requests. The higher level APIs reject suspend requests
237 // for already suspended threads.
238 //
239 // The external_suspend
240 // flag is checked by has_special_runtime_exit_condition() and java thread
241 // will self-suspend when handle_special_runtime_exit_condition() is
242 // called. Most uses of the _thread_blocked state in JavaThreads are
243 // considered the same as being externally suspended; if the blocking
244 // condition lifts, the JavaThread will self-suspend. Other places
245 // where VM checks for external_suspend include:
246 // + mutex granting (do not enter monitors when thread is suspended)
247 // + state transitions from _thread_in_native
248 //
249 // In general, java_suspend() does not wait for an external suspend
250 // request to complete. When it returns, the only guarantee is that
251 // the _external_suspend field is true.
252 //
253 // wait_for_ext_suspend_completion() is used to wait for an external
254 // suspend request to complete. External suspend requests are usually
255 // followed by some other interface call that requires the thread to
256 // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into
257 // the interface that requires quiescence, we give the JavaThread a
258 // chance to self-suspend before we need it to be quiescent. This
259 // improves overall suspend/query performance.
260 //
261 // _suspend_flags controls the behavior of java_ suspend/resume.
262 // It must be set under the protection of SR_lock. Read from the flag is
263 // OK without SR_lock as long as the value is only used as a hint.
264 // (e.g., check _external_suspend first without lock and then recheck
265 // inside SR_lock and finish the suspension)
266 //
267 // _suspend_flags is also overloaded for other "special conditions" so
268 // that a single check indicates whether any special action is needed
269 // eg. for async exceptions.
270 // -------------------------------------------------------------------
271 // Notes:
272 // 1. The suspend/resume logic no longer uses ThreadState in OSThread
273 // but we still update its value to keep other part of the system (mainly
274 // JVMTI) happy. ThreadState is legacy code (see notes in
275 // osThread.hpp).
276 //
277 // 2. It would be more natural if set_external_suspend() is private and
278 // part of java_suspend(), but that probably would affect the suspend/query
279 // performance. Need more investigation on this.
280
281 // suspend/resume lock: used for self-suspend
282 Monitor* _SR_lock;
283
284 protected:
285 enum SuspendFlags {
286 // NOTE: avoid using the sign-bit as cc generates different test code
287 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077
288
289 _external_suspend = 0x20000000U, // thread is asked to self suspend
290 _ext_suspended = 0x40000000U, // thread has self-suspended
291
292 _has_async_exception = 0x00000001U, // there is a pending async exception
293 _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock
294
295 _trace_flag = 0x00000004U // call tracing backend
296 };
297
298 // various suspension related flags - atomically updated
299 // overloaded for async exception checking in check_special_condition_for_native_trans.
300 volatile uint32_t _suspend_flags;
301
302 private:
303 int _num_nested_signal;
304
305 DEBUG_ONLY(bool _suspendible_thread;)
306
307 public:
308 void enter_signal_handler() { _num_nested_signal++; }
309 void leave_signal_handler() { _num_nested_signal--; }
310 bool is_inside_signal_handler() const { return _num_nested_signal > 0; }
311
312 // Determines if a heap allocation failure will be retried
313 // (e.g., by deoptimizing and re-executing in the interpreter).
314 // In this case, the failed allocation must raise
315 // Universe::out_of_memory_error_retry() and omit side effects
316 // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError
317 // and -XX:OnOutOfMemoryError.
318 virtual bool in_retryable_allocation() const { return false; }
319
320 #ifdef ASSERT
321 void set_suspendible_thread() {
322 _suspendible_thread = true;
323 }
324
325 void clear_suspendible_thread() {
326 _suspendible_thread = false;
327 }
328
329 bool is_suspendible_thread() { return _suspendible_thread; }
330 #endif
331
332 private:
333 // Active_handles points to a block of handles
334 JNIHandleBlock* _active_handles;
335
336 // One-element thread local free list
337 JNIHandleBlock* _free_handle_block;
338
339 // Point to the last handle mark
340 HandleMark* _last_handle_mark;
341
342 // Claim value for parallel iteration over threads.
343 uintx _threads_do_token;
344
345 // Support for GlobalCounter
346 private:
347 volatile uintx _rcu_counter;
348 public:
349 volatile uintx* get_rcu_counter() {
350 return &_rcu_counter;
351 }
352
353 public:
354 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; }
355 HandleMark* last_handle_mark() const { return _last_handle_mark; }
356 private:
357
358 #ifdef ASSERT
359 ICRefillVerifier* _missed_ic_stub_refill_verifier;
360
361 public:
362 ICRefillVerifier* missed_ic_stub_refill_verifier() {
363 return _missed_ic_stub_refill_verifier;
364 }
365
366 void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) {
367 _missed_ic_stub_refill_verifier = verifier;
368 }
369 #endif // ASSERT
370
371 private:
372
373 // Debug support for checking if code allows safepoints or not.
374 // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on
375 // mutex, or blocking on an object synchronizer (Java locking).
376 // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of
377 // the above cases.
378 //
379 // The class NoSafepointVerifier is used to set this counter.
380 //
381 NOT_PRODUCT(int _no_safepoint_count;) // If 0, thread allow a safepoint to happen
382
383 private:
384 // Used by SkipGCALot class.
385 NOT_PRODUCT(bool _skip_gcalot;) // Should we elide gc-a-lot?
386
387 friend class GCLocker;
388 friend class NoSafepointVerifier;
389 friend class PauseNoSafepointVerifier;
390
391 volatile void* _polling_page; // Thread local polling page
392
393 ThreadLocalAllocBuffer _tlab; // Thread-local eden
394 jlong _allocated_bytes; // Cumulative number of bytes allocated on
395 // the Java heap
396 ThreadHeapSampler _heap_sampler; // For use when sampling the memory.
397
398 ThreadStatisticalInfo _statistical_info; // Statistics about the thread
399
400 JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;) // Thread-local data for jfr
401
402 int _vm_operation_started_count; // VM_Operation support
403 int _vm_operation_completed_count; // VM_Operation support
404
405 ObjectMonitor* _current_pending_monitor; // ObjectMonitor this thread
406 // is waiting to lock
407 bool _current_pending_monitor_is_from_java; // locking is from Java code
408 JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread
409 // is waiting to lock
410
411
412 // ObjectMonitor on which this thread called Object.wait()
413 ObjectMonitor* _current_waiting_monitor;
414
415 // Per-thread ObjectMonitor lists:
416 public:
417 ObjectMonitor* om_free_list; // SLL of free ObjectMonitors
418 int om_free_count; // # on om_free_list
419 int om_free_provision; // # to try to allocate next
420 ObjectMonitor* om_in_use_list; // SLL of in-use ObjectMonitors
421 int om_in_use_count; // # on om_in_use_list
422
423 #ifdef ASSERT
424 private:
425 volatile uint64_t _visited_for_critical_count;
426
427 public:
428 void set_visited_for_critical_count(uint64_t safepoint_id) {
429 assert(_visited_for_critical_count == 0, "Must be reset before set");
430 assert((safepoint_id & 0x1) == 1, "Must be odd");
431 _visited_for_critical_count = safepoint_id;
432 }
433 void reset_visited_for_critical_count(uint64_t safepoint_id) {
434 assert(_visited_for_critical_count == safepoint_id, "Was not visited");
435 _visited_for_critical_count = 0;
436 }
437 bool was_visited_for_critical_count(uint64_t safepoint_id) const {
438 return _visited_for_critical_count == safepoint_id;
439 }
440 #endif
441
442 public:
443 enum {
444 is_definitely_current_thread = true
445 };
446
447 // Constructor
448 Thread();
449 virtual ~Thread() = 0; // Thread is abstract.
450
451 // Manage Thread::current()
452 void initialize_thread_current();
453 static void clear_thread_current(); // TLS cleanup needed before threads terminate
454
455 protected:
456 // To be implemented by children.
457 virtual void run() = 0;
458 virtual void pre_run() = 0;
459 virtual void post_run() = 0; // Note: Thread must not be deleted prior to calling this!
460
461 #ifdef ASSERT
462 enum RunState {
463 PRE_CALL_RUN,
464 CALL_RUN,
465 PRE_RUN,
466 RUN,
467 POST_RUN
468 // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it
469 };
470 RunState _run_state; // for lifecycle checks
471 #endif
472
473
474 public:
475 // invokes <ChildThreadClass>::run(), with common preparations and cleanups.
476 void call_run();
477
478 // Testers
479 virtual bool is_VM_thread() const { return false; }
480 virtual bool is_Java_thread() const { return false; }
481 virtual bool is_Compiler_thread() const { return false; }
482 virtual bool is_Code_cache_sweeper_thread() const { return false; }
483 virtual bool is_service_thread() const { return false; }
484 virtual bool is_hidden_from_external_view() const { return false; }
485 virtual bool is_jvmti_agent_thread() const { return false; }
486 // True iff the thread can perform GC operations at a safepoint.
487 // Generally will be true only of VM thread and parallel GC WorkGang
488 // threads.
489 virtual bool is_GC_task_thread() const { return false; }
490 virtual bool is_Watcher_thread() const { return false; }
491 virtual bool is_ConcurrentGC_thread() const { return false; }
492 virtual bool is_Named_thread() const { return false; }
493 virtual bool is_Worker_thread() const { return false; }
494
495 // Can this thread make Java upcalls
496 virtual bool can_call_java() const { return false; }
497
498 // Is this a JavaThread that is on the VM's current ThreadsList?
499 // If so it must participate in the safepoint protocol.
500 virtual bool is_active_Java_thread() const { return false; }
501
502 // Casts
503 virtual WorkerThread* as_Worker_thread() const { return NULL; }
504
505 virtual char* name() const { return (char*)"Unknown thread"; }
506
507 // Returns the current thread (ASSERTS if NULL)
508 static inline Thread* current();
509 // Returns the current thread, or NULL if not attached
510 static inline Thread* current_or_null();
511 // Returns the current thread, or NULL if not attached, and is
512 // safe for use from signal-handlers
513 static inline Thread* current_or_null_safe();
514
515 // Common thread operations
516 #ifdef ASSERT
517 static void check_for_dangling_thread_pointer(Thread *thread);
518 #endif
519 static void set_priority(Thread* thread, ThreadPriority priority);
520 static ThreadPriority get_priority(const Thread* const thread);
521 static void start(Thread* thread);
522
523 void set_native_thread_name(const char *name) {
524 assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread");
525 os::set_native_thread_name(name);
526 }
527
528 Monitor* SR_lock() const { return _SR_lock; }
529
530 bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; }
531
532 inline void set_suspend_flag(SuspendFlags f);
533 inline void clear_suspend_flag(SuspendFlags f);
534
535 inline void set_has_async_exception();
536 inline void clear_has_async_exception();
537
538 bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; }
539
540 inline void set_critical_native_unlock();
541 inline void clear_critical_native_unlock();
542
543 inline void set_trace_flag();
544 inline void clear_trace_flag();
545
546 // Support for Unhandled Oop detection
547 // Add the field for both, fastdebug and debug, builds to keep
548 // Thread's fields layout the same.
549 // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build.
550 #ifdef CHECK_UNHANDLED_OOPS
551 private:
552 UnhandledOops* _unhandled_oops;
553 #elif defined(ASSERT)
554 private:
555 void* _unhandled_oops;
556 #endif
557 #ifdef CHECK_UNHANDLED_OOPS
558 public:
559 UnhandledOops* unhandled_oops() { return _unhandled_oops; }
560 // Mark oop safe for gc. It may be stack allocated but won't move.
561 void allow_unhandled_oop(oop *op) {
562 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op);
563 }
564 // Clear oops at safepoint so crashes point to unhandled oop violator
565 void clear_unhandled_oops() {
566 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops();
567 }
568 #endif // CHECK_UNHANDLED_OOPS
569
570 public:
571 #ifndef PRODUCT
572 bool skip_gcalot() { return _skip_gcalot; }
573 void set_skip_gcalot(bool v) { _skip_gcalot = v; }
574 #endif
575
576 // Installs a pending exception to be inserted later
577 static void send_async_exception(oop thread_oop, oop java_throwable);
578
579 // Resource area
580 ResourceArea* resource_area() const { return _resource_area; }
581 void set_resource_area(ResourceArea* area) { _resource_area = area; }
582
583 OSThread* osthread() const { return _osthread; }
584 void set_osthread(OSThread* thread) { _osthread = thread; }
585
586 // JNI handle support
587 JNIHandleBlock* active_handles() const { return _active_handles; }
588 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; }
589 JNIHandleBlock* free_handle_block() const { return _free_handle_block; }
590 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; }
591
592 // Internal handle support
593 HandleArea* handle_area() const { return _handle_area; }
594 void set_handle_area(HandleArea* area) { _handle_area = area; }
595
596 GrowableArray<Metadata*>* metadata_handles() const { return _metadata_handles; }
597 void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; }
598
599 // Thread-Local Allocation Buffer (TLAB) support
600 ThreadLocalAllocBuffer& tlab() { return _tlab; }
601 void initialize_tlab() {
602 if (UseTLAB) {
603 tlab().initialize();
604 }
605 }
606
607 jlong allocated_bytes() { return _allocated_bytes; }
608 void set_allocated_bytes(jlong value) { _allocated_bytes = value; }
609 void incr_allocated_bytes(jlong size) { _allocated_bytes += size; }
610 inline jlong cooked_allocated_bytes();
611
612 ThreadHeapSampler& heap_sampler() { return _heap_sampler; }
613
614 ThreadStatisticalInfo& statistical_info() { return _statistical_info; }
615
616 JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;)
617
618 bool is_trace_suspend() { return (_suspend_flags & _trace_flag) != 0; }
619
620 // VM operation support
621 int vm_operation_ticket() { return ++_vm_operation_started_count; }
622 int vm_operation_completed_count() { return _vm_operation_completed_count; }
623 void increment_vm_operation_completed_count() { _vm_operation_completed_count++; }
624
625 // For tracking the heavyweight monitor the thread is pending on.
626 ObjectMonitor* current_pending_monitor() {
627 return _current_pending_monitor;
628 }
629 void set_current_pending_monitor(ObjectMonitor* monitor) {
630 _current_pending_monitor = monitor;
631 }
632 void set_current_pending_monitor_is_from_java(bool from_java) {
633 _current_pending_monitor_is_from_java = from_java;
634 }
635 bool current_pending_monitor_is_from_java() {
636 return _current_pending_monitor_is_from_java;
637 }
638
639 // For tracking the ObjectMonitor on which this thread called Object.wait()
640 ObjectMonitor* current_waiting_monitor() {
641 return _current_waiting_monitor;
642 }
643 void set_current_waiting_monitor(ObjectMonitor* monitor) {
644 _current_waiting_monitor = monitor;
645 }
646
647 // For tracking the Jvmti raw monitor the thread is pending on.
648 JvmtiRawMonitor* current_pending_raw_monitor() {
649 return _current_pending_raw_monitor;
650 }
651 void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) {
652 _current_pending_raw_monitor = monitor;
653 }
654
655 // GC support
656 // Apply "f->do_oop" to all root oops in "this".
657 // Used by JavaThread::oops_do.
658 // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames
659 virtual void oops_do(OopClosure* f, CodeBlobClosure* cf);
660
661 // Handles the parallel case for claim_threads_do.
662 private:
663 bool claim_par_threads_do(uintx claim_token);
664 public:
665 // Requires that "claim_token" is that of the current iteration.
666 // If "is_par" is false, sets the token of "this" to
667 // "claim_token", and returns "true". If "is_par" is true,
668 // uses an atomic instruction to set the current thread's token to
669 // "claim_token", if it is not already. Returns "true" iff the
670 // calling thread does the update, this indicates that the calling thread
671 // has claimed the thread in the current iteration.
672 bool claim_threads_do(bool is_par, uintx claim_token) {
673 if (!is_par) {
674 _threads_do_token = claim_token;
675 return true;
676 } else {
677 return claim_par_threads_do(claim_token);
678 }
679 }
680
681 uintx threads_do_token() const { return _threads_do_token; }
682
683 // jvmtiRedefineClasses support
684 void metadata_handles_do(void f(Metadata*));
685
686 private:
687 // Check if address is within the given range of this thread's
688 // stack: stack_base() > adr >/>= limit
689 // The check is inclusive of limit if passed true, else exclusive.
690 bool is_in_stack_range(address adr, address limit, bool inclusive) const {
691 assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack");
692 return stack_base() > adr && (inclusive ? adr >= limit : adr > limit);
693 }
694
695 public:
696 // Used by fast lock support
697 virtual bool is_lock_owned(address adr) const;
698
699 // Check if address is within the given range of this thread's
700 // stack: stack_base() > adr >= limit
701 bool is_in_stack_range_incl(address adr, address limit) const {
702 return is_in_stack_range(adr, limit, true);
703 }
704
705 // Check if address is within the given range of this thread's
706 // stack: stack_base() > adr > limit
707 bool is_in_stack_range_excl(address adr, address limit) const {
708 return is_in_stack_range(adr, limit, false);
709 }
710
711 // Check if address is in the stack mapped to this thread. Used mainly in
712 // error reporting (so has to include guard zone) and frame printing.
713 // Expects _stack_base to be initialized - checked with assert.
714 bool is_in_full_stack_checked(address adr) const {
715 return is_in_stack_range_incl(adr, stack_end());
716 }
717
718 // Like is_in_full_stack_checked but without the assertions as this
719 // may be called in a thread before _stack_base is initialized.
720 bool is_in_full_stack(address adr) const {
721 address stack_end = _stack_base - _stack_size;
722 return _stack_base > adr && adr >= stack_end;
723 }
724
725 // Check if address is in the live stack of this thread (not just for locks).
726 // Warning: can only be called by the current thread on itself.
727 bool is_in_live_stack(address adr) const {
728 assert(Thread::current() == this, "is_in_live_stack can only be called from current thread");
729 return is_in_stack_range_incl(adr, os::current_stack_pointer());
730 }
731
732 // Sets this thread as starting thread. Returns failure if thread
733 // creation fails due to lack of memory, too many threads etc.
734 bool set_as_starting_thread();
735
736 protected:
737 // OS data associated with the thread
738 OSThread* _osthread; // Platform-specific thread information
739
740 // Thread local resource area for temporary allocation within the VM
741 ResourceArea* _resource_area;
742
743 DEBUG_ONLY(ResourceMark* _current_resource_mark;)
744
745 // Thread local handle area for allocation of handles within the VM
746 HandleArea* _handle_area;
747 GrowableArray<Metadata*>* _metadata_handles;
748
749 // Support for stack overflow handling, get_thread, etc.
750 address _stack_base;
751 size_t _stack_size;
752 int _lgrp_id;
753
754 volatile void** polling_page_addr() { return &_polling_page; }
755
756 public:
757 // Stack overflow support
758 address stack_base() const { assert(_stack_base != NULL,"Sanity check"); return _stack_base; }
759 void set_stack_base(address base) { _stack_base = base; }
760 size_t stack_size() const { return _stack_size; }
761 void set_stack_size(size_t size) { _stack_size = size; }
762 address stack_end() const { return stack_base() - stack_size(); }
763 void record_stack_base_and_size();
764 void register_thread_stack_with_NMT() NOT_NMT_RETURN;
765
766 int lgrp_id() const { return _lgrp_id; }
767 void set_lgrp_id(int value) { _lgrp_id = value; }
768
769 // Printing
770 void print_on(outputStream* st, bool print_extended_info) const;
771 virtual void print_on(outputStream* st) const { print_on(st, false); }
772 void print() const;
773 virtual void print_on_error(outputStream* st, char* buf, int buflen) const;
774 void print_value_on(outputStream* st) const;
775
776 // Debug-only code
777 #ifdef ASSERT
778 private:
779 // Deadlock detection support for Mutex locks. List of locks own by thread.
780 Mutex* _owned_locks;
781 // Mutex::set_owner_implementation is the only place where _owned_locks is modified,
782 // thus the friendship
783 friend class Mutex;
784 friend class Monitor;
785
786 public:
787 void print_owned_locks_on(outputStream* st) const;
788 void print_owned_locks() const { print_owned_locks_on(tty); }
789 Mutex* owned_locks() const { return _owned_locks; }
790 bool owns_locks() const { return owned_locks() != NULL; }
791
792 // Deadlock detection
793 ResourceMark* current_resource_mark() { return _current_resource_mark; }
794 void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; }
795 #endif // ASSERT
796
797 // These functions check conditions on a JavaThread before possibly going to a safepoint,
798 // including NoSafepointVerifier.
799 void check_for_valid_safepoint_state() NOT_DEBUG_RETURN;
800 void check_possible_safepoint() NOT_DEBUG_RETURN;
801
802 private:
803 volatile int _jvmti_env_iteration_count;
804
805 public:
806 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; }
807 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; }
808 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; }
809
810 // Code generation
811 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file); }
812 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line); }
813 static ByteSize active_handles_offset() { return byte_offset_of(Thread, _active_handles); }
814
815 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base); }
816 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size); }
817
818 static ByteSize polling_page_offset() { return byte_offset_of(Thread, _polling_page); }
819
820 static ByteSize tlab_start_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); }
821 static ByteSize tlab_end_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); }
822 static ByteSize tlab_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); }
823 static ByteSize tlab_pf_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); }
824
825 static ByteSize allocated_bytes_offset() { return byte_offset_of(Thread, _allocated_bytes); }
826
827 JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;)
828
829 public:
830 volatile intptr_t _Stalled;
831 volatile int _TypeTag;
832 ParkEvent * _ParkEvent; // for Object monitors and JVMTI raw monitors
833 ParkEvent * _MuxEvent; // for low-level muxAcquire-muxRelease
834 int NativeSyncRecursion; // diagnostic
835
836 volatile int _OnTrap; // Resume-at IP delta
837 jint _hashStateW; // Marsaglia Shift-XOR thread-local RNG
838 jint _hashStateX; // thread-specific hashCode generator state
839 jint _hashStateY;
840 jint _hashStateZ;
841
842 // Low-level leaf-lock primitives used to implement synchronization
843 // and native monitor-mutex infrastructure.
844 // Not for general synchronization use.
845 static void SpinAcquire(volatile int * Lock, const char * Name);
846 static void SpinRelease(volatile int * Lock);
847 static void muxAcquire(volatile intptr_t * Lock, const char * Name);
848 static void muxRelease(volatile intptr_t * Lock);
849 };
850
851 // Inline implementation of Thread::current()
852 inline Thread* Thread::current() {
853 Thread* current = current_or_null();
854 assert(current != NULL, "Thread::current() called on detached thread");
855 return current;
856 }
857
858 inline Thread* Thread::current_or_null() {
859 #ifndef USE_LIBRARY_BASED_TLS_ONLY
860 return _thr_current;
861 #else
862 if (ThreadLocalStorage::is_initialized()) {
863 return ThreadLocalStorage::thread();
864 }
865 return NULL;
866 #endif
867 }
868
869 inline Thread* Thread::current_or_null_safe() {
870 if (ThreadLocalStorage::is_initialized()) {
871 return ThreadLocalStorage::thread();
872 }
873 return NULL;
874 }
875
876 class NonJavaThread: public Thread {
877 friend class VMStructs;
878
879 NonJavaThread* volatile _next;
880
881 class List;
882 static List _the_list;
883
884 void add_to_the_list();
885 void remove_from_the_list();
886
887 protected:
888 virtual void pre_run();
889 virtual void post_run();
890
891 public:
892 NonJavaThread();
893 ~NonJavaThread();
894
895 class Iterator;
896 };
897
898 // Provides iteration over the list of NonJavaThreads.
899 // List addition occurs in pre_run(), and removal occurs in post_run(),
900 // so that only live fully-initialized threads can be found in the list.
901 // Threads created after an iterator is constructed will not be visited
902 // by the iterator. The scope of an iterator is a critical section; there
903 // must be no safepoint checks in that scope.
904 class NonJavaThread::Iterator : public StackObj {
905 uint _protect_enter;
906 NonJavaThread* _current;
907
908 NONCOPYABLE(Iterator);
909
910 public:
911 Iterator();
912 ~Iterator();
913
914 bool end() const { return _current == NULL; }
915 NonJavaThread* current() const { return _current; }
916 void step();
917 };
918
919 // Name support for threads. non-JavaThread subclasses with multiple
920 // uniquely named instances should derive from this.
921 class NamedThread: public NonJavaThread {
922 friend class VMStructs;
923 enum {
924 max_name_len = 64
925 };
926 private:
927 char* _name;
928 // log JavaThread being processed by oops_do
929 JavaThread* _processed_thread;
930 uint _gc_id; // The current GC id when a thread takes part in GC
931
932 public:
933 NamedThread();
934 ~NamedThread();
935 // May only be called once per thread.
936 void set_name(const char* format, ...) ATTRIBUTE_PRINTF(2, 3);
937 virtual bool is_Named_thread() const { return true; }
938 virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; }
939 JavaThread *processed_thread() { return _processed_thread; }
940 void set_processed_thread(JavaThread *thread) { _processed_thread = thread; }
941 virtual void print_on(outputStream* st) const;
942
943 void set_gc_id(uint gc_id) { _gc_id = gc_id; }
944 uint gc_id() { return _gc_id; }
945 };
946
947 // Worker threads are named and have an id of an assigned work.
948 class WorkerThread: public NamedThread {
949 private:
950 uint _id;
951 public:
952 WorkerThread() : _id(0) { }
953 virtual bool is_Worker_thread() const { return true; }
954
955 virtual WorkerThread* as_Worker_thread() const {
956 assert(is_Worker_thread(), "Dubious cast to WorkerThread*?");
957 return (WorkerThread*) this;
958 }
959
960 void set_id(uint work_id) { _id = work_id; }
961 uint id() const { return _id; }
962 };
963
964 // A single WatcherThread is used for simulating timer interrupts.
965 class WatcherThread: public NonJavaThread {
966 friend class VMStructs;
967 protected:
968 virtual void run();
969
970 private:
971 static WatcherThread* _watcher_thread;
972
973 static bool _startable;
974 // volatile due to at least one lock-free read
975 volatile static bool _should_terminate;
976 public:
977 enum SomeConstants {
978 delay_interval = 10 // interrupt delay in milliseconds
979 };
980
981 // Constructor
982 WatcherThread();
983
984 // No destruction allowed
985 ~WatcherThread() {
986 guarantee(false, "WatcherThread deletion must fix the race with VM termination");
987 }
988
989 // Tester
990 bool is_Watcher_thread() const { return true; }
991
992 // Printing
993 char* name() const { return (char*)"VM Periodic Task Thread"; }
994 void print_on(outputStream* st) const;
995 void unpark();
996
997 // Returns the single instance of WatcherThread
998 static WatcherThread* watcher_thread() { return _watcher_thread; }
999
1000 // Create and start the single instance of WatcherThread, or stop it on shutdown
1001 static void start();
1002 static void stop();
1003 // Only allow start once the VM is sufficiently initialized
1004 // Otherwise the first task to enroll will trigger the start
1005 static void make_startable();
1006 private:
1007 int sleep() const;
1008 };
1009
1010
1011 class CompilerThread;
1012
1013 typedef void (*ThreadFunction)(JavaThread*, TRAPS);
1014
1015 class JavaThread: public Thread {
1016 friend class VMStructs;
1017 friend class JVMCIVMStructs;
1018 friend class WhiteBox;
1019 friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do
1020 private:
1021 bool _on_thread_list; // Is set when this JavaThread is added to the Threads list
1022 OopHandle _threadObj; // The Java level thread object
1023
1024 #ifdef ASSERT
1025 private:
1026 int _java_call_counter;
1027
1028 public:
1029 int java_call_counter() { return _java_call_counter; }
1030 void inc_java_call_counter() { _java_call_counter++; }
1031 void dec_java_call_counter() {
1032 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper");
1033 _java_call_counter--;
1034 }
1035 private: // restore original namespace restriction
1036 #endif // ifdef ASSERT
1037
1038 #ifndef PRODUCT
1039 public:
1040 enum {
1041 jump_ring_buffer_size = 16
1042 };
1043 private: // restore original namespace restriction
1044 #endif
1045
1046 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state
1047
1048 ThreadFunction _entry_point;
1049
1050 JNIEnv _jni_environment;
1051
1052 // Deopt support
1053 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization
1054
1055 CompiledMethod* _deopt_nmethod; // CompiledMethod that is currently being deoptimized
1056 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays
1057 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped
1058 // Because deoptimization is lazy we must save jvmti requests to set locals
1059 // in compiled frames until we deoptimize and we have an interpreter frame.
1060 // This holds the pointer to array (yeah like there might be more than one) of
1061 // description of compiled vframes that have locals that need to be updated.
1062 GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates;
1063
1064 // Handshake value for fixing 6243940. We need a place for the i2c
1065 // adapter to store the callee Method*. This value is NEVER live
1066 // across a gc point so it does NOT have to be gc'd
1067 // The handshake is open ended since we can't be certain that it will
1068 // be NULLed. This is because we rarely ever see the race and end up
1069 // in handle_wrong_method which is the backend of the handshake. See
1070 // code in i2c adapters and handle_wrong_method.
1071
1072 Method* _callee_target;
1073
1074 // Used to pass back results to the interpreter or generated code running Java code.
1075 oop _vm_result; // oop result is GC-preserved
1076 Metadata* _vm_result_2; // non-oop result
1077
1078 // See ReduceInitialCardMarks: this holds the precise space interval of
1079 // the most recent slow path allocation for which compiled code has
1080 // elided card-marks for performance along the fast-path.
1081 MemRegion _deferred_card_mark;
1082
1083 MonitorChunk* _monitor_chunks; // Contains the off stack monitors
1084 // allocated during deoptimization
1085 // and by JNI_MonitorEnter/Exit
1086
1087 // Async. requests support
1088 enum AsyncRequests {
1089 _no_async_condition = 0,
1090 _async_exception,
1091 _async_unsafe_access_error
1092 };
1093 AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request
1094 oop _pending_async_exception;
1095
1096 // Safepoint support
1097 public: // Expose _thread_state for SafeFetchInt()
1098 volatile JavaThreadState _thread_state;
1099 private:
1100 ThreadSafepointState* _safepoint_state; // Holds information about a thread during a safepoint
1101 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened
1102
1103 // JavaThread termination support
1104 enum TerminatedTypes {
1105 _not_terminated = 0xDEAD - 2,
1106 _thread_exiting, // JavaThread::exit() has been called for this thread
1107 _thread_terminated, // JavaThread is removed from thread list
1108 _vm_exited // JavaThread is still executing native code, but VM is terminated
1109 // only VM_Exit can set _vm_exited
1110 };
1111
1112 // In general a JavaThread's _terminated field transitions as follows:
1113 //
1114 // _not_terminated => _thread_exiting => _thread_terminated
1115 //
1116 // _vm_exited is a special value to cover the case of a JavaThread
1117 // executing native code after the VM itself is terminated.
1118 volatile TerminatedTypes _terminated;
1119 // suspend/resume support
1120 volatile bool _suspend_equivalent; // Suspend equivalent condition
1121 jint _in_deopt_handler; // count of deoptimization
1122 // handlers thread is in
1123 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access
1124 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was
1125 // never locked) when throwing an exception. Used by interpreter only.
1126
1127 // JNI attach states:
1128 enum JNIAttachStates {
1129 _not_attaching_via_jni = 1, // thread is not attaching via JNI
1130 _attaching_via_jni, // thread is attaching via JNI
1131 _attached_via_jni // thread has attached via JNI
1132 };
1133
1134 // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni.
1135 // A native thread that is attaching via JNI starts with a value
1136 // of _attaching_via_jni and transitions to _attached_via_jni.
1137 volatile JNIAttachStates _jni_attach_state;
1138
1139 public:
1140 // State of the stack guard pages for this thread.
1141 enum StackGuardState {
1142 stack_guard_unused, // not needed
1143 stack_guard_reserved_disabled,
1144 stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow
1145 stack_guard_enabled // enabled
1146 };
1147
1148 private:
1149
1150 #if INCLUDE_JVMCI
1151 // The _pending_* fields below are used to communicate extra information
1152 // from an uncommon trap in JVMCI compiled code to the uncommon trap handler.
1153
1154 // Communicates the DeoptReason and DeoptAction of the uncommon trap
1155 int _pending_deoptimization;
1156
1157 // Specifies whether the uncommon trap is to bci 0 of a synchronized method
1158 // before the monitor has been acquired.
1159 bool _pending_monitorenter;
1160
1161 // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter
1162 bool _pending_transfer_to_interpreter;
1163
1164 // True if in a runtime call from compiled code that will deoptimize
1165 // and re-execute a failed heap allocation in the interpreter.
1166 bool _in_retryable_allocation;
1167
1168 // An id of a speculation that JVMCI compiled code can use to further describe and
1169 // uniquely identify the speculative optimization guarded by the uncommon trap
1170 jlong _pending_failed_speculation;
1171
1172 // These fields are mutually exclusive in terms of live ranges.
1173 union {
1174 // Communicates the pc at which the most recent implicit exception occurred
1175 // from the signal handler to a deoptimization stub.
1176 address _implicit_exception_pc;
1177
1178 // Communicates an alternative call target to an i2c stub from a JavaCall .
1179 address _alternate_call_target;
1180 } _jvmci;
1181
1182 // Support for high precision, thread sensitive counters in JVMCI compiled code.
1183 jlong* _jvmci_counters;
1184
1185 public:
1186 static jlong* _jvmci_old_thread_counters;
1187 static void collect_counters(jlong* array, int length);
1188
1189 bool resize_counters(int current_size, int new_size);
1190
1191 static bool resize_all_jvmci_counters(int new_size);
1192
1193 private:
1194 #endif // INCLUDE_JVMCI
1195
1196 StackGuardState _stack_guard_state;
1197
1198 // Precompute the limit of the stack as used in stack overflow checks.
1199 // We load it from here to simplify the stack overflow check in assembly.
1200 address _stack_overflow_limit;
1201 address _reserved_stack_activation;
1202
1203 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is
1204 // used to temp. parsing values into and out of the runtime system during exception handling for compiled
1205 // code)
1206 volatile oop _exception_oop; // Exception thrown in compiled code
1207 volatile address _exception_pc; // PC where exception happened
1208 volatile address _exception_handler_pc; // PC for handler of exception
1209 volatile int _is_method_handle_return; // true (== 1) if the current exception PC is a MethodHandle call site.
1210
1211 private:
1212 // support for JNI critical regions
1213 jint _jni_active_critical; // count of entries into JNI critical region
1214
1215 // Checked JNI: function name requires exception check
1216 char* _pending_jni_exception_check_fn;
1217
1218 // For deadlock detection.
1219 int _depth_first_number;
1220
1221 // JVMTI PopFrame support
1222 // This is set to popframe_pending to signal that top Java frame should be popped immediately
1223 int _popframe_condition;
1224
1225 // If reallocation of scalar replaced objects fails, we throw OOM
1226 // and during exception propagation, pop the top
1227 // _frames_to_pop_failed_realloc frames, the ones that reference
1228 // failed reallocations.
1229 int _frames_to_pop_failed_realloc;
1230
1231 friend class VMThread;
1232 friend class ThreadWaitTransition;
1233 friend class VM_Exit;
1234
1235 void initialize(); // Initialized the instance variables
1236
1237 public:
1238 // Constructor
1239 JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads
1240 JavaThread(ThreadFunction entry_point, size_t stack_size = 0);
1241 ~JavaThread();
1242
1243 #ifdef ASSERT
1244 // verify this JavaThread hasn't be published in the Threads::list yet
1245 void verify_not_published();
1246 #endif // ASSERT
1247
1248 //JNI functiontable getter/setter for JVMTI jni function table interception API.
1249 void set_jni_functions(struct JNINativeInterface_* functionTable) {
1250 _jni_environment.functions = functionTable;
1251 }
1252 struct JNINativeInterface_* get_jni_functions() {
1253 return (struct JNINativeInterface_ *)_jni_environment.functions;
1254 }
1255
1256 // This function is called at thread creation to allow
1257 // platform specific thread variables to be initialized.
1258 void cache_global_variables();
1259
1260 // Executes Shutdown.shutdown()
1261 void invoke_shutdown_hooks();
1262
1263 // Cleanup on thread exit
1264 enum ExitType {
1265 normal_exit,
1266 jni_detach
1267 };
1268 void exit(bool destroy_vm, ExitType exit_type = normal_exit);
1269
1270 void cleanup_failed_attach_current_thread(bool is_daemon);
1271
1272 // Testers
1273 virtual bool is_Java_thread() const { return true; }
1274 virtual bool can_call_java() const { return true; }
1275
1276 virtual bool is_active_Java_thread() const {
1277 return on_thread_list() && !is_terminated();
1278 }
1279
1280 // Thread oop. threadObj() can be NULL for initial JavaThread
1281 // (or for threads attached via JNI)
1282 oop threadObj() const;
1283 void set_threadObj(oop p);
1284
1285 // Prepare thread and add to priority queue. If a priority is
1286 // not specified, use the priority of the thread object. Threads_lock
1287 // must be held while this function is called.
1288 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority);
1289
1290 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; }
1291 address saved_exception_pc() { return _saved_exception_pc; }
1292
1293
1294 ThreadFunction entry_point() const { return _entry_point; }
1295
1296 // Allocates a new Java level thread object for this thread. thread_name may be NULL.
1297 void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS);
1298
1299 // Last frame anchor routines
1300
1301 JavaFrameAnchor* frame_anchor(void) { return &_anchor; }
1302
1303 // last_Java_sp
1304 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); }
1305 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); }
1306
1307 // last_Java_pc
1308
1309 address last_Java_pc(void) { return _anchor.last_Java_pc(); }
1310
1311 // Safepoint support
1312 inline JavaThreadState thread_state() const;
1313 inline void set_thread_state(JavaThreadState s);
1314 inline void set_thread_state_fence(JavaThreadState s); // fence after setting thread state
1315 inline ThreadSafepointState* safepoint_state() const;
1316 inline void set_safepoint_state(ThreadSafepointState* state);
1317 inline bool is_at_poll_safepoint();
1318
1319 // JavaThread termination and lifecycle support:
1320 void smr_delete();
1321 bool on_thread_list() const { return _on_thread_list; }
1322 void set_on_thread_list() { _on_thread_list = true; }
1323
1324 // thread has called JavaThread::exit() or is terminated
1325 bool is_exiting() const;
1326 // thread is terminated (no longer on the threads list); we compare
1327 // against the two non-terminated values so that a freed JavaThread
1328 // will also be considered terminated.
1329 bool check_is_terminated(TerminatedTypes l_terminated) const {
1330 return l_terminated != _not_terminated && l_terminated != _thread_exiting;
1331 }
1332 bool is_terminated() const;
1333 void set_terminated(TerminatedTypes t);
1334 // special for Threads::remove() which is static:
1335 void set_terminated_value();
1336 void block_if_vm_exited();
1337
1338 bool doing_unsafe_access() { return _doing_unsafe_access; }
1339 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; }
1340
1341 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; }
1342 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; }
1343
1344 inline void set_polling_page_release(void* poll_value);
1345 inline void set_polling_page(void* poll_value);
1346 inline volatile void* get_polling_page();
1347
1348 private:
1349 // Support for thread handshake operations
1350 HandshakeState _handshake;
1351 public:
1352 void set_handshake_operation(HandshakeOperation* op) {
1353 _handshake.set_operation(op);
1354 }
1355
1356 bool has_handshake() const {
1357 return _handshake.has_operation();
1358 }
1359
1360 void handshake_process_by_self() {
1361 _handshake.process_by_self();
1362 }
1363
1364 HandshakeState::ProcessResult handshake_try_process(HandshakeOperation* op) {
1365 return _handshake.try_process(op);
1366 }
1367
1368 #ifdef ASSERT
1369 Thread* active_handshaker() const {
1370 return _handshake.active_handshaker();
1371 }
1372 #endif
1373
1374 // Suspend/resume support for JavaThread
1375 private:
1376 inline void set_ext_suspended();
1377 inline void clear_ext_suspended();
1378
1379 public:
1380 void java_suspend(); // higher-level suspension logic called by the public APIs
1381 void java_resume(); // higher-level resume logic called by the public APIs
1382 int java_suspend_self(); // low-level self-suspension mechanics
1383
1384 private:
1385 // mid-level wrapper around java_suspend_self to set up correct state and
1386 // check for a pending safepoint at the end
1387 void java_suspend_self_with_safepoint_check();
1388
1389 public:
1390 void check_and_wait_while_suspended() {
1391 assert(JavaThread::current() == this, "sanity check");
1392
1393 bool do_self_suspend;
1394 do {
1395 // were we externally suspended while we were waiting?
1396 do_self_suspend = handle_special_suspend_equivalent_condition();
1397 if (do_self_suspend) {
1398 // don't surprise the thread that suspended us by returning
1399 java_suspend_self();
1400 set_suspend_equivalent();
1401 }
1402 } while (do_self_suspend);
1403 }
1404 static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread);
1405 // Check for async exception in addition to safepoint and suspend request.
1406 static void check_special_condition_for_native_trans(JavaThread *thread);
1407
1408 // Same as check_special_condition_for_native_trans but finishes the
1409 // transition into thread_in_Java mode so that it can potentially
1410 // block.
1411 static void check_special_condition_for_native_trans_and_transition(JavaThread *thread);
1412
1413 bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits);
1414 bool is_ext_suspend_completed_with_lock(uint32_t *bits) {
1415 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1416 // Warning: is_ext_suspend_completed() may temporarily drop the
1417 // SR_lock to allow the thread to reach a stable thread state if
1418 // it is currently in a transient thread state.
1419 return is_ext_suspend_completed(false /* !called_by_wait */,
1420 SuspendRetryDelay, bits);
1421 }
1422
1423 // We cannot allow wait_for_ext_suspend_completion() to run forever or
1424 // we could hang. SuspendRetryCount and SuspendRetryDelay are normally
1425 // passed as the count and delay parameters. Experiments with specific
1426 // calls to wait_for_ext_suspend_completion() can be done by passing
1427 // other values in the code. Experiments with all calls can be done
1428 // via the appropriate -XX options.
1429 bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits);
1430
1431 // test for suspend - most (all?) of these should go away
1432 bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits);
1433
1434 inline void set_external_suspend();
1435 inline void clear_external_suspend();
1436
1437 bool is_external_suspend() const {
1438 return (_suspend_flags & _external_suspend) != 0;
1439 }
1440 // Whenever a thread transitions from native to vm/java it must suspend
1441 // if external|deopt suspend is present.
1442 bool is_suspend_after_native() const {
1443 return (_suspend_flags & (_external_suspend JFR_ONLY(| _trace_flag))) != 0;
1444 }
1445
1446 // external suspend request is completed
1447 bool is_ext_suspended() const {
1448 return (_suspend_flags & _ext_suspended) != 0;
1449 }
1450
1451 bool is_external_suspend_with_lock() const {
1452 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1453 return is_external_suspend();
1454 }
1455
1456 // Special method to handle a pending external suspend request
1457 // when a suspend equivalent condition lifts.
1458 bool handle_special_suspend_equivalent_condition() {
1459 assert(is_suspend_equivalent(),
1460 "should only be called in a suspend equivalence condition");
1461 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1462 bool ret = is_external_suspend();
1463 if (!ret) {
1464 // not about to self-suspend so clear suspend equivalence
1465 clear_suspend_equivalent();
1466 }
1467 // implied else:
1468 // We have a pending external suspend request so we leave the
1469 // suspend_equivalent flag set until java_suspend_self() sets
1470 // the ext_suspended flag and clears the suspend_equivalent
1471 // flag. This insures that wait_for_ext_suspend_completion()
1472 // will return consistent values.
1473 return ret;
1474 }
1475
1476 // utility methods to see if we are doing some kind of suspension
1477 bool is_being_ext_suspended() const {
1478 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag);
1479 return is_ext_suspended() || is_external_suspend();
1480 }
1481
1482 bool is_suspend_equivalent() const { return _suspend_equivalent; }
1483
1484 void set_suspend_equivalent() { _suspend_equivalent = true; }
1485 void clear_suspend_equivalent() { _suspend_equivalent = false; }
1486
1487 // Thread.stop support
1488 void send_thread_stop(oop throwable);
1489 AsyncRequests clear_special_runtime_exit_condition() {
1490 AsyncRequests x = _special_runtime_exit_condition;
1491 _special_runtime_exit_condition = _no_async_condition;
1492 return x;
1493 }
1494
1495 // Are any async conditions present?
1496 bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); }
1497
1498 void check_and_handle_async_exceptions(bool check_unsafe_error = true);
1499
1500 // these next two are also used for self-suspension and async exception support
1501 void handle_special_runtime_exit_condition(bool check_asyncs = true);
1502
1503 // Return true if JavaThread has an asynchronous condition or
1504 // if external suspension is requested.
1505 bool has_special_runtime_exit_condition() {
1506 // Because we don't use is_external_suspend_with_lock
1507 // it is possible that we won't see an asynchronous external suspend
1508 // request that has just gotten started, i.e., SR_lock grabbed but
1509 // _external_suspend field change either not made yet or not visible
1510 // yet. However, this is okay because the request is asynchronous and
1511 // we will see the new flag value the next time through. It's also
1512 // possible that the external suspend request is dropped after
1513 // we have checked is_external_suspend(), we will recheck its value
1514 // under SR_lock in java_suspend_self().
1515 return (_special_runtime_exit_condition != _no_async_condition) ||
1516 is_external_suspend() || is_trace_suspend();
1517 }
1518
1519 void set_pending_unsafe_access_error() { _special_runtime_exit_condition = _async_unsafe_access_error; }
1520
1521 inline void set_pending_async_exception(oop e);
1522
1523 // Fast-locking support
1524 bool is_lock_owned(address adr) const;
1525
1526 // Accessors for vframe array top
1527 // The linked list of vframe arrays are sorted on sp. This means when we
1528 // unpack the head must contain the vframe array to unpack.
1529 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; }
1530 vframeArray* vframe_array_head() const { return _vframe_array_head; }
1531
1532 // Side structure for deferring update of java frame locals until deopt occurs
1533 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; }
1534 void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; }
1535
1536 // These only really exist to make debugging deopt problems simpler
1537
1538 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; }
1539 vframeArray* vframe_array_last() const { return _vframe_array_last; }
1540
1541 // The special resourceMark used during deoptimization
1542
1543 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; }
1544 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; }
1545
1546 void set_deopt_compiled_method(CompiledMethod* nm) { _deopt_nmethod = nm; }
1547 CompiledMethod* deopt_compiled_method() { return _deopt_nmethod; }
1548
1549 Method* callee_target() const { return _callee_target; }
1550 void set_callee_target (Method* x) { _callee_target = x; }
1551
1552 // Oop results of vm runtime calls
1553 oop vm_result() const { return _vm_result; }
1554 void set_vm_result (oop x) { _vm_result = x; }
1555
1556 Metadata* vm_result_2() const { return _vm_result_2; }
1557 void set_vm_result_2 (Metadata* x) { _vm_result_2 = x; }
1558
1559 MemRegion deferred_card_mark() const { return _deferred_card_mark; }
1560 void set_deferred_card_mark(MemRegion mr) { _deferred_card_mark = mr; }
1561
1562 #if INCLUDE_JVMCI
1563 int pending_deoptimization() const { return _pending_deoptimization; }
1564 jlong pending_failed_speculation() const { return _pending_failed_speculation; }
1565 bool has_pending_monitorenter() const { return _pending_monitorenter; }
1566 void set_pending_monitorenter(bool b) { _pending_monitorenter = b; }
1567 void set_pending_deoptimization(int reason) { _pending_deoptimization = reason; }
1568 void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; }
1569 void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; }
1570 void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; }
1571 void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; }
1572
1573 virtual bool in_retryable_allocation() const { return _in_retryable_allocation; }
1574 void set_in_retryable_allocation(bool b) { _in_retryable_allocation = b; }
1575 #endif // INCLUDE_JVMCI
1576
1577 // Exception handling for compiled methods
1578 oop exception_oop() const;
1579 address exception_pc() const { return _exception_pc; }
1580 address exception_handler_pc() const { return _exception_handler_pc; }
1581 bool is_method_handle_return() const { return _is_method_handle_return == 1; }
1582
1583 void set_exception_oop(oop o);
1584 void set_exception_pc(address a) { _exception_pc = a; }
1585 void set_exception_handler_pc(address a) { _exception_handler_pc = a; }
1586 void set_is_method_handle_return(bool value) { _is_method_handle_return = value ? 1 : 0; }
1587
1588 void clear_exception_oop_and_pc() {
1589 set_exception_oop(NULL);
1590 set_exception_pc(NULL);
1591 }
1592
1593 // Stack overflow support
1594 //
1595 // (small addresses)
1596 //
1597 // -- <-- stack_end() ---
1598 // | |
1599 // | red pages |
1600 // | |
1601 // -- <-- stack_red_zone_base() |
1602 // | |
1603 // | guard
1604 // | yellow pages zone
1605 // | |
1606 // | |
1607 // -- <-- stack_yellow_zone_base() |
1608 // | |
1609 // | |
1610 // | reserved pages |
1611 // | |
1612 // -- <-- stack_reserved_zone_base() --- ---
1613 // /|\ shadow <-- stack_overflow_limit() (somewhere in here)
1614 // | zone
1615 // \|/ size
1616 // some untouched memory ---
1617 //
1618 //
1619 // --
1620 // |
1621 // | shadow zone
1622 // |
1623 // --
1624 // x frame n
1625 // --
1626 // x frame n-1
1627 // x
1628 // --
1629 // ...
1630 //
1631 // --
1632 // x frame 0
1633 // -- <-- stack_base()
1634 //
1635 // (large addresses)
1636 //
1637
1638 private:
1639 // These values are derived from flags StackRedPages, StackYellowPages,
1640 // StackReservedPages and StackShadowPages. The zone size is determined
1641 // ergonomically if page_size > 4K.
1642 static size_t _stack_red_zone_size;
1643 static size_t _stack_yellow_zone_size;
1644 static size_t _stack_reserved_zone_size;
1645 static size_t _stack_shadow_zone_size;
1646 public:
1647 inline size_t stack_available(address cur_sp);
1648
1649 static size_t stack_red_zone_size() {
1650 assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized.");
1651 return _stack_red_zone_size;
1652 }
1653 static void set_stack_red_zone_size(size_t s) {
1654 assert(is_aligned(s, os::vm_page_size()),
1655 "We can not protect if the red zone size is not page aligned.");
1656 assert(_stack_red_zone_size == 0, "This should be called only once.");
1657 _stack_red_zone_size = s;
1658 }
1659 address stack_red_zone_base() {
1660 return (address)(stack_end() + stack_red_zone_size());
1661 }
1662 bool in_stack_red_zone(address a) {
1663 return a <= stack_red_zone_base() && a >= stack_end();
1664 }
1665
1666 static size_t stack_yellow_zone_size() {
1667 assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized.");
1668 return _stack_yellow_zone_size;
1669 }
1670 static void set_stack_yellow_zone_size(size_t s) {
1671 assert(is_aligned(s, os::vm_page_size()),
1672 "We can not protect if the yellow zone size is not page aligned.");
1673 assert(_stack_yellow_zone_size == 0, "This should be called only once.");
1674 _stack_yellow_zone_size = s;
1675 }
1676
1677 static size_t stack_reserved_zone_size() {
1678 // _stack_reserved_zone_size may be 0. This indicates the feature is off.
1679 return _stack_reserved_zone_size;
1680 }
1681 static void set_stack_reserved_zone_size(size_t s) {
1682 assert(is_aligned(s, os::vm_page_size()),
1683 "We can not protect if the reserved zone size is not page aligned.");
1684 assert(_stack_reserved_zone_size == 0, "This should be called only once.");
1685 _stack_reserved_zone_size = s;
1686 }
1687 address stack_reserved_zone_base() const {
1688 return (address)(stack_end() +
1689 (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size()));
1690 }
1691 bool in_stack_reserved_zone(address a) {
1692 return (a <= stack_reserved_zone_base()) &&
1693 (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size()));
1694 }
1695
1696 static size_t stack_yellow_reserved_zone_size() {
1697 return _stack_yellow_zone_size + _stack_reserved_zone_size;
1698 }
1699 bool in_stack_yellow_reserved_zone(address a) {
1700 return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base());
1701 }
1702
1703 // Size of red + yellow + reserved zones.
1704 static size_t stack_guard_zone_size() {
1705 return stack_red_zone_size() + stack_yellow_reserved_zone_size();
1706 }
1707
1708 static size_t stack_shadow_zone_size() {
1709 assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized.");
1710 return _stack_shadow_zone_size;
1711 }
1712 static void set_stack_shadow_zone_size(size_t s) {
1713 // The shadow area is not allocated or protected, so
1714 // it needs not be page aligned.
1715 // But the stack bang currently assumes that it is a
1716 // multiple of page size. This guarantees that the bang
1717 // loop touches all pages in the shadow zone.
1718 // This can be guaranteed differently, as well. E.g., if
1719 // the page size is a multiple of 4K, banging in 4K steps
1720 // suffices to touch all pages. (Some pages are banged
1721 // several times, though.)
1722 assert(is_aligned(s, os::vm_page_size()),
1723 "Stack bang assumes multiple of page size.");
1724 assert(_stack_shadow_zone_size == 0, "This should be called only once.");
1725 _stack_shadow_zone_size = s;
1726 }
1727
1728 void create_stack_guard_pages();
1729 void remove_stack_guard_pages();
1730
1731 void enable_stack_reserved_zone();
1732 void disable_stack_reserved_zone();
1733 void enable_stack_yellow_reserved_zone();
1734 void disable_stack_yellow_reserved_zone();
1735 void enable_stack_red_zone();
1736 void disable_stack_red_zone();
1737
1738 inline bool stack_guard_zone_unused();
1739 inline bool stack_yellow_reserved_zone_disabled();
1740 inline bool stack_reserved_zone_disabled();
1741 inline bool stack_guards_enabled();
1742
1743 address reserved_stack_activation() const { return _reserved_stack_activation; }
1744 void set_reserved_stack_activation(address addr) {
1745 assert(_reserved_stack_activation == stack_base()
1746 || _reserved_stack_activation == NULL
1747 || addr == stack_base(), "Must not be set twice");
1748 _reserved_stack_activation = addr;
1749 }
1750
1751 // Attempt to reguard the stack after a stack overflow may have occurred.
1752 // Returns true if (a) guard pages are not needed on this thread, (b) the
1753 // pages are already guarded, or (c) the pages were successfully reguarded.
1754 // Returns false if there is not enough stack space to reguard the pages, in
1755 // which case the caller should unwind a frame and try again. The argument
1756 // should be the caller's (approximate) sp.
1757 bool reguard_stack(address cur_sp);
1758 // Similar to above but see if current stackpoint is out of the guard area
1759 // and reguard if possible.
1760 bool reguard_stack(void);
1761
1762 address stack_overflow_limit() { return _stack_overflow_limit; }
1763 void set_stack_overflow_limit() {
1764 _stack_overflow_limit =
1765 stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size());
1766 }
1767
1768 // Check if address is in the usable part of the stack (excludes protected
1769 // guard pages). Can be applied to any thread and is an approximation for
1770 // using is_in_live_stack when the query has to happen from another thread.
1771 bool is_in_usable_stack(address adr) const {
1772 return is_in_stack_range_incl(adr, stack_reserved_zone_base());
1773 }
1774
1775 // Misc. accessors/mutators
1776 void set_do_not_unlock(void) { _do_not_unlock_if_synchronized = true; }
1777 void clr_do_not_unlock(void) { _do_not_unlock_if_synchronized = false; }
1778 bool do_not_unlock(void) { return _do_not_unlock_if_synchronized; }
1779
1780 // For assembly stub generation
1781 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj); }
1782 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment); }
1783 static ByteSize pending_jni_exception_check_fn_offset() {
1784 return byte_offset_of(JavaThread, _pending_jni_exception_check_fn);
1785 }
1786 static ByteSize last_Java_sp_offset() {
1787 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset();
1788 }
1789 static ByteSize last_Java_pc_offset() {
1790 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset();
1791 }
1792 static ByteSize frame_anchor_offset() {
1793 return byte_offset_of(JavaThread, _anchor);
1794 }
1795 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target); }
1796 static ByteSize vm_result_offset() { return byte_offset_of(JavaThread, _vm_result); }
1797 static ByteSize vm_result_2_offset() { return byte_offset_of(JavaThread, _vm_result_2); }
1798 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state); }
1799 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc); }
1800 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread); }
1801 #if INCLUDE_JVMCI
1802 static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); }
1803 static ByteSize pending_monitorenter_offset() { return byte_offset_of(JavaThread, _pending_monitorenter); }
1804 static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); }
1805 static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); }
1806 static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); }
1807 static ByteSize jvmci_counters_offset() { return byte_offset_of(JavaThread, _jvmci_counters); }
1808 #endif // INCLUDE_JVMCI
1809 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop); }
1810 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc); }
1811 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); }
1812 static ByteSize stack_overflow_limit_offset() { return byte_offset_of(JavaThread, _stack_overflow_limit); }
1813 static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); }
1814 static ByteSize stack_guard_state_offset() { return byte_offset_of(JavaThread, _stack_guard_state); }
1815 static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); }
1816 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags); }
1817
1818 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); }
1819 static ByteSize should_post_on_exceptions_flag_offset() {
1820 return byte_offset_of(JavaThread, _should_post_on_exceptions_flag);
1821 }
1822 static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); }
1823
1824 // Returns the jni environment for this thread
1825 JNIEnv* jni_environment() { return &_jni_environment; }
1826
1827 static JavaThread* thread_from_jni_environment(JNIEnv* env) {
1828 JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset()));
1829 // Only return NULL if thread is off the thread list; starting to
1830 // exit should not return NULL.
1831 if (thread_from_jni_env->is_terminated()) {
1832 thread_from_jni_env->block_if_vm_exited();
1833 return NULL;
1834 } else {
1835 return thread_from_jni_env;
1836 }
1837 }
1838
1839 // JNI critical regions. These can nest.
1840 bool in_critical() { return _jni_active_critical > 0; }
1841 bool in_last_critical() { return _jni_active_critical == 1; }
1842 inline void enter_critical();
1843 void exit_critical() {
1844 assert(Thread::current() == this, "this must be current thread");
1845 _jni_active_critical--;
1846 assert(_jni_active_critical >= 0, "JNI critical nesting problem?");
1847 }
1848
1849 // Checked JNI: is the programmer required to check for exceptions, if so specify
1850 // which function name. Returning to a Java frame should implicitly clear the
1851 // pending check, this is done for Native->Java transitions (i.e. user JNI code).
1852 // VM->Java transistions are not cleared, it is expected that JNI code enclosed
1853 // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal).
1854 bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; }
1855 void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; }
1856 const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; }
1857 void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; }
1858
1859 // For deadlock detection
1860 int depth_first_number() { return _depth_first_number; }
1861 void set_depth_first_number(int dfn) { _depth_first_number = dfn; }
1862
1863 private:
1864 void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; }
1865
1866 public:
1867 MonitorChunk* monitor_chunks() const { return _monitor_chunks; }
1868 void add_monitor_chunk(MonitorChunk* chunk);
1869 void remove_monitor_chunk(MonitorChunk* chunk);
1870 bool in_deopt_handler() const { return _in_deopt_handler > 0; }
1871 void inc_in_deopt_handler() { _in_deopt_handler++; }
1872 void dec_in_deopt_handler() {
1873 assert(_in_deopt_handler > 0, "mismatched deopt nesting");
1874 if (_in_deopt_handler > 0) { // robustness
1875 _in_deopt_handler--;
1876 }
1877 }
1878
1879 private:
1880 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; }
1881
1882 public:
1883
1884 // Frame iteration; calls the function f for all frames on the stack
1885 void frames_do(void f(frame*, const RegisterMap*));
1886
1887 // Memory operations
1888 void oops_do(OopClosure* f, CodeBlobClosure* cf);
1889
1890 // Sweeper operations
1891 virtual void nmethods_do(CodeBlobClosure* cf);
1892
1893 // RedefineClasses Support
1894 void metadata_do(MetadataClosure* f);
1895
1896 // Debug method asserting thread states are correct during a handshake operation.
1897 DEBUG_ONLY(void verify_states_for_handshake();)
1898
1899 // Misc. operations
1900 char* name() const { return (char*)get_thread_name(); }
1901 void print_on(outputStream* st, bool print_extended_info) const;
1902 void print_on(outputStream* st) const { print_on(st, false); }
1903 void print() const;
1904 void print_thread_state_on(outputStream*) const PRODUCT_RETURN;
1905 void print_on_error(outputStream* st, char* buf, int buflen) const;
1906 void print_name_on_error(outputStream* st, char* buf, int buflen) const;
1907 void verify();
1908 const char* get_thread_name() const;
1909 protected:
1910 // factor out low-level mechanics for use in both normal and error cases
1911 virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const;
1912 public:
1913 // Accessing frames
1914 frame last_frame() {
1915 _anchor.make_walkable(this);
1916 return pd_last_frame();
1917 }
1918 javaVFrame* last_java_vframe(RegisterMap* reg_map);
1919
1920 // Returns method at 'depth' java or native frames down the stack
1921 // Used for security checks
1922 Klass* security_get_caller_class(int depth);
1923
1924 // Print stack trace in external format
1925 void print_stack_on(outputStream* st);
1926 void print_stack() { print_stack_on(tty); }
1927
1928 // Print stack traces in various internal formats
1929 void trace_stack() PRODUCT_RETURN;
1930 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN;
1931 void trace_frames() PRODUCT_RETURN;
1932
1933 // Print an annotated view of the stack frames
1934 void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN;
1935 void validate_frame_layout() {
1936 print_frame_layout(0, true);
1937 }
1938
1939 // Function for testing deoptimization
1940 void deoptimize();
1941 void make_zombies();
1942
1943 void deoptimize_marked_methods();
1944
1945 public:
1946 // Returns the running thread as a JavaThread
1947 static inline JavaThread* current();
1948
1949 // Returns the active Java thread. Do not use this if you know you are calling
1950 // from a JavaThread, as it's slower than JavaThread::current. If called from
1951 // the VMThread, it also returns the JavaThread that instigated the VMThread's
1952 // operation. You may not want that either.
1953 static JavaThread* active();
1954
1955 inline CompilerThread* as_CompilerThread();
1956
1957 protected:
1958 virtual void pre_run();
1959 virtual void run();
1960 void thread_main_inner();
1961 virtual void post_run();
1962
1963
1964 private:
1965 GrowableArray<oop>* _array_for_gc;
1966 public:
1967
1968 void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; }
1969
1970 public:
1971 // Thread local information maintained by JVMTI.
1972 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; }
1973 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state()
1974 // getter is used to get this JavaThread's JvmtiThreadState if it has
1975 // one which means NULL can be returned. JvmtiThreadState::state_for()
1976 // is used to get the specified JavaThread's JvmtiThreadState if it has
1977 // one or it allocates a new JvmtiThreadState for the JavaThread and
1978 // returns it. JvmtiThreadState::state_for() will return NULL only if
1979 // the specified JavaThread is exiting.
1980 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; }
1981 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); }
1982
1983 // JVMTI PopFrame support
1984 // Setting and clearing popframe_condition
1985 // All of these enumerated values are bits. popframe_pending
1986 // indicates that a PopFrame() has been requested and not yet been
1987 // completed. popframe_processing indicates that that PopFrame() is in
1988 // the process of being completed. popframe_force_deopt_reexecution_bit
1989 // indicates that special handling is required when returning to a
1990 // deoptimized caller.
1991 enum PopCondition {
1992 popframe_inactive = 0x00,
1993 popframe_pending_bit = 0x01,
1994 popframe_processing_bit = 0x02,
1995 popframe_force_deopt_reexecution_bit = 0x04
1996 };
1997 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; }
1998 void set_popframe_condition(PopCondition c) { _popframe_condition = c; }
1999 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; }
2000 void clear_popframe_condition() { _popframe_condition = popframe_inactive; }
2001 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); }
2002 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; }
2003 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; }
2004 void clear_popframe_forcing_deopt_reexecution() { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; }
2005
2006 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); }
2007 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; }
2008 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; }
2009
2010 int frames_to_pop_failed_realloc() const { return _frames_to_pop_failed_realloc; }
2011 void set_frames_to_pop_failed_realloc(int nb) { _frames_to_pop_failed_realloc = nb; }
2012 void dec_frames_to_pop_failed_realloc() { _frames_to_pop_failed_realloc--; }
2013
2014 private:
2015 // Saved incoming arguments to popped frame.
2016 // Used only when popped interpreted frame returns to deoptimized frame.
2017 void* _popframe_preserved_args;
2018 int _popframe_preserved_args_size;
2019
2020 public:
2021 void popframe_preserve_args(ByteSize size_in_bytes, void* start);
2022 void* popframe_preserved_args();
2023 ByteSize popframe_preserved_args_size();
2024 WordSize popframe_preserved_args_size_in_words();
2025 void popframe_free_preserved_args();
2026
2027
2028 private:
2029 JvmtiThreadState *_jvmti_thread_state;
2030
2031 // Used by the interpreter in fullspeed mode for frame pop, method
2032 // entry, method exit and single stepping support. This field is
2033 // only set to non-zero at a safepoint or using a direct handshake
2034 // (see EnterInterpOnlyModeClosure).
2035 // It can be set to zero asynchronously to this threads execution (i.e., without
2036 // safepoint/handshake or a lock) so we have to be very careful.
2037 // Accesses by other threads are synchronized using JvmtiThreadState_lock though.
2038 int _interp_only_mode;
2039
2040 public:
2041 // used by the interpreter for fullspeed debugging support (see above)
2042 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); }
2043 bool is_interp_only_mode() { return (_interp_only_mode != 0); }
2044 int get_interp_only_mode() { return _interp_only_mode; }
2045 void increment_interp_only_mode() { ++_interp_only_mode; }
2046 void decrement_interp_only_mode() { --_interp_only_mode; }
2047
2048 // support for cached flag that indicates whether exceptions need to be posted for this thread
2049 // if this is false, we can avoid deoptimizing when events are thrown
2050 // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything
2051 private:
2052 int _should_post_on_exceptions_flag;
2053
2054 public:
2055 int should_post_on_exceptions_flag() { return _should_post_on_exceptions_flag; }
2056 void set_should_post_on_exceptions_flag(int val) { _should_post_on_exceptions_flag = val; }
2057
2058 private:
2059 ThreadStatistics *_thread_stat;
2060
2061 public:
2062 ThreadStatistics* get_thread_stat() const { return _thread_stat; }
2063
2064 // Return a blocker object for which this thread is blocked parking.
2065 oop current_park_blocker();
2066
2067 private:
2068 static size_t _stack_size_at_create;
2069
2070 public:
2071 static inline size_t stack_size_at_create(void) {
2072 return _stack_size_at_create;
2073 }
2074 static inline void set_stack_size_at_create(size_t value) {
2075 _stack_size_at_create = value;
2076 }
2077
2078 // Machine dependent stuff
2079 #include OS_CPU_HEADER(thread)
2080
2081 // JSR166 per-thread parker
2082 private:
2083 Parker* _parker;
2084 public:
2085 Parker* parker() { return _parker; }
2086
2087 // Biased locking support
2088 private:
2089 GrowableArray<MonitorInfo*>* _cached_monitor_info;
2090 public:
2091 GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; }
2092 void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; }
2093
2094 // clearing/querying jni attach status
2095 bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; }
2096 bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; }
2097 inline void set_done_attaching_via_jni();
2098
2099 // Stack dump assistance:
2100 // Track the class we want to initialize but for which we have to wait
2101 // on its init_lock() because it is already being initialized.
2102 void set_class_to_be_initialized(InstanceKlass* k);
2103 InstanceKlass* class_to_be_initialized() const;
2104
2105 private:
2106 InstanceKlass* _class_to_be_initialized;
2107
2108 // java.lang.Thread.sleep support
2109 ParkEvent * _SleepEvent;
2110 public:
2111 bool sleep(jlong millis);
2112
2113 // java.lang.Thread interruption support
2114 void interrupt();
2115 bool is_interrupted(bool clear_interrupted);
2116
2117 static OopStorage* thread_oop_storage();
2118 };
2119
2120 // Inline implementation of JavaThread::current
2121 inline JavaThread* JavaThread::current() {
2122 Thread* thread = Thread::current();
2123 assert(thread->is_Java_thread(), "just checking");
2124 return (JavaThread*)thread;
2125 }
2126
2127 inline CompilerThread* JavaThread::as_CompilerThread() {
2128 assert(is_Compiler_thread(), "just checking");
2129 return (CompilerThread*)this;
2130 }
2131
2132 // Dedicated thread to sweep the code cache
2133 class CodeCacheSweeperThread : public JavaThread {
2134 CompiledMethod* _scanned_compiled_method; // nmethod being scanned by the sweeper
2135 public:
2136 CodeCacheSweeperThread();
2137 // Track the nmethod currently being scanned by the sweeper
2138 void set_scanned_compiled_method(CompiledMethod* cm) {
2139 assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value");
2140 _scanned_compiled_method = cm;
2141 }
2142
2143 // Hide sweeper thread from external view.
2144 bool is_hidden_from_external_view() const { return true; }
2145
2146 bool is_Code_cache_sweeper_thread() const { return true; }
2147
2148 // Prevent GC from unloading _scanned_compiled_method
2149 void oops_do(OopClosure* f, CodeBlobClosure* cf);
2150 void nmethods_do(CodeBlobClosure* cf);
2151 };
2152
2153 // A thread used for Compilation.
2154 class CompilerThread : public JavaThread {
2155 friend class VMStructs;
2156 private:
2157 CompilerCounters* _counters;
2158
2159 ciEnv* _env;
2160 CompileLog* _log;
2161 CompileTask* volatile _task; // print_threads_compiling can read this concurrently.
2162 CompileQueue* _queue;
2163 BufferBlob* _buffer_blob;
2164
2165 AbstractCompiler* _compiler;
2166 TimeStamp _idle_time;
2167
2168 public:
2169
2170 static CompilerThread* current();
2171
2172 CompilerThread(CompileQueue* queue, CompilerCounters* counters);
2173 ~CompilerThread();
2174
2175 bool is_Compiler_thread() const { return true; }
2176
2177 virtual bool can_call_java() const;
2178
2179 // Hide native compiler threads from external view.
2180 bool is_hidden_from_external_view() const { return !can_call_java(); }
2181
2182 void set_compiler(AbstractCompiler* c) { _compiler = c; }
2183 AbstractCompiler* compiler() const { return _compiler; }
2184
2185 CompileQueue* queue() const { return _queue; }
2186 CompilerCounters* counters() const { return _counters; }
2187
2188 // Get/set the thread's compilation environment.
2189 ciEnv* env() { return _env; }
2190 void set_env(ciEnv* env) { _env = env; }
2191
2192 BufferBlob* get_buffer_blob() const { return _buffer_blob; }
2193 void set_buffer_blob(BufferBlob* b) { _buffer_blob = b; }
2194
2195 // Get/set the thread's logging information
2196 CompileLog* log() { return _log; }
2197 void init_log(CompileLog* log) {
2198 // Set once, for good.
2199 assert(_log == NULL, "set only once");
2200 _log = log;
2201 }
2202
2203 void start_idle_timer() { _idle_time.update(); }
2204 jlong idle_time_millis() {
2205 return TimeHelper::counter_to_millis(_idle_time.ticks_since_update());
2206 }
2207
2208 #ifndef PRODUCT
2209 private:
2210 IdealGraphPrinter *_ideal_graph_printer;
2211 public:
2212 IdealGraphPrinter *ideal_graph_printer() { return _ideal_graph_printer; }
2213 void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; }
2214 #endif
2215
2216 // Get/set the thread's current task
2217 CompileTask* task() { return _task; }
2218 void set_task(CompileTask* task) { _task = task; }
2219 };
2220
2221 inline CompilerThread* CompilerThread::current() {
2222 return JavaThread::current()->as_CompilerThread();
2223 }
2224
2225 // The active thread queue. It also keeps track of the current used
2226 // thread priorities.
2227 class Threads: AllStatic {
2228 friend class VMStructs;
2229 private:
2230 static int _number_of_threads;
2231 static int _number_of_non_daemon_threads;
2232 static int _return_code;
2233 static uintx _thread_claim_token;
2234 #ifdef ASSERT
2235 static bool _vm_complete;
2236 #endif
2237
2238 static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS);
2239 static void initialize_jsr292_core_classes(TRAPS);
2240
2241 public:
2242 // Thread management
2243 // force_daemon is a concession to JNI, where we may need to add a
2244 // thread to the thread list before allocating its thread object
2245 static void add(JavaThread* p, bool force_daemon = false);
2246 static void remove(JavaThread* p, bool is_daemon);
2247 static void non_java_threads_do(ThreadClosure* tc);
2248 static void java_threads_do(ThreadClosure* tc);
2249 static void java_threads_and_vm_thread_do(ThreadClosure* tc);
2250 static void threads_do(ThreadClosure* tc);
2251 static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc);
2252
2253 // Initializes the vm and creates the vm thread
2254 static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain);
2255 static void convert_vm_init_libraries_to_agents();
2256 static void create_vm_init_libraries();
2257 static void create_vm_init_agents();
2258 static void shutdown_vm_agents();
2259 static bool destroy_vm();
2260 // Supported VM versions via JNI
2261 // Includes JNI_VERSION_1_1
2262 static jboolean is_supported_jni_version_including_1_1(jint version);
2263 // Does not include JNI_VERSION_1_1
2264 static jboolean is_supported_jni_version(jint version);
2265
2266 // The "thread claim token" provides a way for threads to be claimed
2267 // by parallel worker tasks.
2268 //
2269 // Each thread contains a "token" field. A task will claim the
2270 // thread only if its token is different from the global token,
2271 // which is updated by calling change_thread_claim_token(). When
2272 // a thread is claimed, it's token is set to the global token value
2273 // so other threads in the same iteration pass won't claim it.
2274 //
2275 // For this to work change_thread_claim_token() needs to be called
2276 // exactly once in sequential code before starting parallel tasks
2277 // that should claim threads.
2278 //
2279 // New threads get their token set to 0 and change_thread_claim_token()
2280 // never sets the global token to 0.
2281 static uintx thread_claim_token() { return _thread_claim_token; }
2282 static void change_thread_claim_token();
2283 static void assert_all_threads_claimed() NOT_DEBUG_RETURN;
2284
2285 // Apply "f->do_oop" to all root oops in all threads.
2286 // This version may only be called by sequential code.
2287 static void oops_do(OopClosure* f, CodeBlobClosure* cf);
2288 // This version may be called by sequential or parallel code.
2289 static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf);
2290
2291 // Sweeper
2292 static void nmethods_do(CodeBlobClosure* cf);
2293
2294 // RedefineClasses support
2295 static void metadata_do(MetadataClosure* f);
2296 static void metadata_handles_do(void f(Metadata*));
2297
2298 #ifdef ASSERT
2299 static bool is_vm_complete() { return _vm_complete; }
2300 #endif // ASSERT
2301
2302 // Verification
2303 static void verify();
2304 static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info);
2305 static void print(bool print_stacks, bool internal_format) {
2306 // this function is only used by debug.cpp
2307 print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */);
2308 }
2309 static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen);
2310 static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
2311 int buflen, bool* found_current);
2312 static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false);
2313
2314 // Get Java threads that are waiting to enter a monitor.
2315 static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list,
2316 int count, address monitor);
2317
2318 // Get owning Java thread from the monitor's owner field.
2319 static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list,
2320 address owner);
2321
2322 // Number of threads on the active threads list
2323 static int number_of_threads() { return _number_of_threads; }
2324 // Number of non-daemon threads on the active threads list
2325 static int number_of_non_daemon_threads() { return _number_of_non_daemon_threads; }
2326
2327 // Deoptimizes all frames tied to marked nmethods
2328 static void deoptimized_wrt_marked_nmethods();
2329
2330 struct Test; // For private gtest access.
2331 };
2332
2333 class SignalHandlerMark: public StackObj {
2334 private:
2335 Thread* _thread;
2336 public:
2337 SignalHandlerMark(Thread* t) {
2338 _thread = t;
2339 if (_thread) _thread->enter_signal_handler();
2340 }
2341 ~SignalHandlerMark() {
2342 if (_thread) _thread->leave_signal_handler();
2343 _thread = NULL;
2344 }
2345 };
2346
2347 class UnlockFlagSaver {
2348 private:
2349 JavaThread* _thread;
2350 bool _do_not_unlock;
2351 public:
2352 UnlockFlagSaver(JavaThread* t) {
2353 _thread = t;
2354 _do_not_unlock = t->do_not_unlock_if_synchronized();
2355 t->set_do_not_unlock_if_synchronized(false);
2356 }
2357 ~UnlockFlagSaver() {
2358 _thread->set_do_not_unlock_if_synchronized(_do_not_unlock);
2359 }
2360 };
2361
2362 #endif // SHARE_RUNTIME_THREAD_HPP