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 JvmtiDeferredUpdates; 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 DEBUG_ONLY(class ResourceMark;) 96 97 class WorkerThread; 98 99 // Class hierarchy 100 // - Thread 101 // - JavaThread 102 // - various subclasses eg CompilerThread, ServiceThread 103 // - NonJavaThread 104 // - NamedThread 105 // - VMThread 106 // - ConcurrentGCThread 107 // - WorkerThread 108 // - GangWorker 109 // - WatcherThread 110 // - JfrThreadSampler 111 // 112 // All Thread subclasses must be either JavaThread or NonJavaThread. 113 // This means !t->is_Java_thread() iff t is a NonJavaThread, or t is 114 // a partially constructed/destroyed Thread. 115 116 // Thread execution sequence and actions: 117 // All threads: 118 // - thread_native_entry // per-OS native entry point 119 // - stack initialization 120 // - other OS-level initialization (signal masks etc) 121 // - handshake with creating thread (if not started suspended) 122 // - this->call_run() // common shared entry point 123 // - shared common initialization 124 // - this->pre_run() // virtual per-thread-type initialization 125 // - this->run() // virtual per-thread-type "main" logic 126 // - shared common tear-down 127 // - this->post_run() // virtual per-thread-type tear-down 128 // - // 'this' no longer referenceable 129 // - OS-level tear-down (minimal) 130 // - final logging 131 // 132 // For JavaThread: 133 // - this->run() // virtual but not normally overridden 134 // - this->thread_main_inner() // extra call level to ensure correct stack calculations 135 // - this->entry_point() // set differently for each kind of JavaThread 136 137 class Thread: public ThreadShadow { 138 friend class VMStructs; 139 friend class JVMCIVMStructs; 140 private: 141 142 #ifndef USE_LIBRARY_BASED_TLS_ONLY 143 // Current thread is maintained as a thread-local variable 144 static THREAD_LOCAL Thread* _thr_current; 145 #endif 146 147 // Thread local data area available to the GC. The internal 148 // structure and contents of this data area is GC-specific. 149 // Only GC and GC barrier code should access this data area. 150 GCThreadLocalData _gc_data; 151 152 public: 153 static ByteSize gc_data_offset() { 154 return byte_offset_of(Thread, _gc_data); 155 } 156 157 template <typename T> T* gc_data() { 158 STATIC_ASSERT(sizeof(T) <= sizeof(_gc_data)); 159 return reinterpret_cast<T*>(&_gc_data); 160 } 161 162 // Exception handling 163 // (Note: _pending_exception and friends are in ThreadShadow) 164 //oop _pending_exception; // pending exception for current thread 165 // const char* _exception_file; // file information for exception (debugging only) 166 // int _exception_line; // line information for exception (debugging only) 167 protected: 168 169 DEBUG_ONLY(static Thread* _starting_thread;) 170 171 // Support for forcing alignment of thread objects for biased locking 172 void* _real_malloc_address; 173 174 // JavaThread lifecycle support: 175 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 176 friend class ScanHazardPtrGatherProtectedThreadsClosure; // for cmpxchg_threads_hazard_ptr(), get_threads_hazard_ptr(), is_hazard_ptr_tagged() access 177 friend class ScanHazardPtrGatherThreadsListClosure; // for get_threads_hazard_ptr(), untag_hazard_ptr() access 178 friend class ScanHazardPtrPrintMatchingThreadsClosure; // for get_threads_hazard_ptr(), is_hazard_ptr_tagged() access 179 friend class ThreadsSMRSupport; // for _nested_threads_hazard_ptr_cnt, _threads_hazard_ptr, _threads_list_ptr access 180 181 ThreadsList* volatile _threads_hazard_ptr; 182 SafeThreadsListPtr* _threads_list_ptr; 183 ThreadsList* cmpxchg_threads_hazard_ptr(ThreadsList* exchange_value, ThreadsList* compare_value); 184 ThreadsList* get_threads_hazard_ptr(); 185 void set_threads_hazard_ptr(ThreadsList* new_list); 186 static bool is_hazard_ptr_tagged(ThreadsList* list) { 187 return (intptr_t(list) & intptr_t(1)) == intptr_t(1); 188 } 189 static ThreadsList* tag_hazard_ptr(ThreadsList* list) { 190 return (ThreadsList*)(intptr_t(list) | intptr_t(1)); 191 } 192 static ThreadsList* untag_hazard_ptr(ThreadsList* list) { 193 return (ThreadsList*)(intptr_t(list) & ~intptr_t(1)); 194 } 195 // This field is enabled via -XX:+EnableThreadSMRStatistics: 196 uint _nested_threads_hazard_ptr_cnt; 197 void dec_nested_threads_hazard_ptr_cnt() { 198 assert(_nested_threads_hazard_ptr_cnt != 0, "mismatched {dec,inc}_nested_threads_hazard_ptr_cnt()"); 199 _nested_threads_hazard_ptr_cnt--; 200 } 201 void inc_nested_threads_hazard_ptr_cnt() { 202 _nested_threads_hazard_ptr_cnt++; 203 } 204 uint nested_threads_hazard_ptr_cnt() { 205 return _nested_threads_hazard_ptr_cnt; 206 } 207 208 public: 209 void* operator new(size_t size) throw() { return allocate(size, true); } 210 void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() { 211 return allocate(size, false); } 212 void operator delete(void* p); 213 214 protected: 215 static void* allocate(size_t size, bool throw_excpt, MEMFLAGS flags = mtThread); 216 private: 217 218 // *************************************************************** 219 // Suspend and resume support 220 // *************************************************************** 221 // 222 // VM suspend/resume no longer exists - it was once used for various 223 // things including safepoints but was deprecated and finally removed 224 // in Java 7. Because VM suspension was considered "internal" Java-level 225 // suspension was considered "external", and this legacy naming scheme 226 // remains. 227 // 228 // External suspend/resume requests come from JVM_SuspendThread, 229 // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI 230 // ResumeThread. External 231 // suspend requests cause _external_suspend to be set and external 232 // resume requests cause _external_suspend to be cleared. 233 // External suspend requests do not nest on top of other external 234 // suspend requests. The higher level APIs reject suspend requests 235 // for already suspended threads. 236 // 237 // The external_suspend 238 // flag is checked by has_special_runtime_exit_condition() and java thread 239 // will self-suspend when handle_special_runtime_exit_condition() is 240 // called. Most uses of the _thread_blocked state in JavaThreads are 241 // considered the same as being externally suspended; if the blocking 242 // condition lifts, the JavaThread will self-suspend. Other places 243 // where VM checks for external_suspend include: 244 // + mutex granting (do not enter monitors when thread is suspended) 245 // + state transitions from _thread_in_native 246 // 247 // In general, java_suspend() does not wait for an external suspend 248 // request to complete. When it returns, the only guarantee is that 249 // the _external_suspend field is true. 250 // 251 // wait_for_ext_suspend_completion() is used to wait for an external 252 // suspend request to complete. External suspend requests are usually 253 // followed by some other interface call that requires the thread to 254 // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into 255 // the interface that requires quiescence, we give the JavaThread a 256 // chance to self-suspend before we need it to be quiescent. This 257 // improves overall suspend/query performance. 258 // 259 // _suspend_flags controls the behavior of java_ suspend/resume. 260 // It must be set under the protection of SR_lock. Read from the flag is 261 // OK without SR_lock as long as the value is only used as a hint. 262 // (e.g., check _external_suspend first without lock and then recheck 263 // inside SR_lock and finish the suspension) 264 // 265 // _suspend_flags is also overloaded for other "special conditions" so 266 // that a single check indicates whether any special action is needed 267 // eg. for async exceptions. 268 // ------------------------------------------------------------------- 269 // Notes: 270 // 1. The suspend/resume logic no longer uses ThreadState in OSThread 271 // but we still update its value to keep other part of the system (mainly 272 // JVMTI) happy. ThreadState is legacy code (see notes in 273 // osThread.hpp). 274 // 275 // 2. It would be more natural if set_external_suspend() is private and 276 // part of java_suspend(), but that probably would affect the suspend/query 277 // performance. Need more investigation on this. 278 279 // suspend/resume lock: used for self-suspend 280 Monitor* _SR_lock; 281 282 protected: 283 enum SuspendFlags { 284 // NOTE: avoid using the sign-bit as cc generates different test code 285 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077 286 287 _external_suspend = 0x20000000U, // thread is asked to self suspend 288 _ext_suspended = 0x40000000U, // thread has self-suspended 289 290 _has_async_exception = 0x00000001U, // there is a pending async exception 291 _critical_native_unlock = 0x00000002U, // Must call back to unlock JNI critical lock 292 293 _trace_flag = 0x00000004U, // call tracing backend 294 _obj_deopt = 0x00000008U // suspend for object reallocation and relocking for JVMTI agent 295 }; 296 297 // various suspension related flags - atomically updated 298 // overloaded for async exception checking in check_special_condition_for_native_trans. 299 volatile uint32_t _suspend_flags; 300 301 private: 302 int _num_nested_signal; 303 304 DEBUG_ONLY(bool _suspendible_thread;) 305 306 public: 307 void enter_signal_handler() { _num_nested_signal++; } 308 void leave_signal_handler() { _num_nested_signal--; } 309 bool is_inside_signal_handler() const { return _num_nested_signal > 0; } 310 311 // Determines if a heap allocation failure will be retried 312 // (e.g., by deoptimizing and re-executing in the interpreter). 313 // In this case, the failed allocation must raise 314 // Universe::out_of_memory_error_retry() and omit side effects 315 // such as JVMTI events and handling -XX:+HeapDumpOnOutOfMemoryError 316 // and -XX:OnOutOfMemoryError. 317 virtual bool in_retryable_allocation() const { return false; } 318 319 #ifdef ASSERT 320 void set_suspendible_thread() { 321 _suspendible_thread = true; 322 } 323 324 void clear_suspendible_thread() { 325 _suspendible_thread = false; 326 } 327 328 bool is_suspendible_thread() { return _suspendible_thread; } 329 #endif 330 331 private: 332 // Active_handles points to a block of handles 333 JNIHandleBlock* _active_handles; 334 335 // One-element thread local free list 336 JNIHandleBlock* _free_handle_block; 337 338 // Point to the last handle mark 339 HandleMark* _last_handle_mark; 340 341 // Claim value for parallel iteration over threads. 342 uintx _threads_do_token; 343 344 // Support for GlobalCounter 345 private: 346 volatile uintx _rcu_counter; 347 public: 348 volatile uintx* get_rcu_counter() { 349 return &_rcu_counter; 350 } 351 352 public: 353 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; } 354 HandleMark* last_handle_mark() const { return _last_handle_mark; } 355 private: 356 357 #ifdef ASSERT 358 ICRefillVerifier* _missed_ic_stub_refill_verifier; 359 360 public: 361 ICRefillVerifier* missed_ic_stub_refill_verifier() { 362 return _missed_ic_stub_refill_verifier; 363 } 364 365 void set_missed_ic_stub_refill_verifier(ICRefillVerifier* verifier) { 366 _missed_ic_stub_refill_verifier = verifier; 367 } 368 #endif // ASSERT 369 370 private: 371 372 // Debug support for checking if code allows safepoints or not. 373 // Safepoints in the VM can happen because of allocation, invoking a VM operation, or blocking on 374 // mutex, or blocking on an object synchronizer (Java locking). 375 // If _no_safepoint_count is non-zero, then an assertion failure will happen in any of 376 // the above cases. 377 // 378 // The class NoSafepointVerifier is used to set this counter. 379 // 380 NOT_PRODUCT(int _no_safepoint_count;) // If 0, thread allow a safepoint to happen 381 382 private: 383 // Used by SkipGCALot class. 384 NOT_PRODUCT(bool _skip_gcalot;) // Should we elide gc-a-lot? 385 386 friend class GCLocker; 387 friend class NoSafepointVerifier; 388 friend class PauseNoSafepointVerifier; 389 390 volatile void* _polling_page; // Thread local polling page 391 392 ThreadLocalAllocBuffer _tlab; // Thread-local eden 393 jlong _allocated_bytes; // Cumulative number of bytes allocated on 394 // the Java heap 395 ThreadHeapSampler _heap_sampler; // For use when sampling the memory. 396 397 ThreadStatisticalInfo _statistical_info; // Statistics about the thread 398 399 JFR_ONLY(DEFINE_THREAD_LOCAL_FIELD_JFR;) // Thread-local data for jfr 400 401 int _vm_operation_started_count; // VM_Operation support 402 int _vm_operation_completed_count; // VM_Operation support 403 404 ObjectMonitor* _current_pending_monitor; // ObjectMonitor this thread 405 // is waiting to lock 406 bool _current_pending_monitor_is_from_java; // locking is from Java code 407 JvmtiRawMonitor* _current_pending_raw_monitor; // JvmtiRawMonitor this thread 408 // is waiting to lock 409 410 411 // ObjectMonitor on which this thread called Object.wait() 412 ObjectMonitor* _current_waiting_monitor; 413 414 // Per-thread ObjectMonitor lists: 415 public: 416 ObjectMonitor* om_free_list; // SLL of free ObjectMonitors 417 int om_free_count; // # on om_free_list 418 int om_free_provision; // # to try to allocate next 419 ObjectMonitor* om_in_use_list; // SLL of in-use ObjectMonitors 420 int om_in_use_count; // # on om_in_use_list 421 422 #ifdef ASSERT 423 private: 424 volatile uint64_t _visited_for_critical_count; 425 426 public: 427 void set_visited_for_critical_count(uint64_t safepoint_id) { 428 assert(_visited_for_critical_count == 0, "Must be reset before set"); 429 assert((safepoint_id & 0x1) == 1, "Must be odd"); 430 _visited_for_critical_count = safepoint_id; 431 } 432 void reset_visited_for_critical_count(uint64_t safepoint_id) { 433 assert(_visited_for_critical_count == safepoint_id, "Was not visited"); 434 _visited_for_critical_count = 0; 435 } 436 bool was_visited_for_critical_count(uint64_t safepoint_id) const { 437 return _visited_for_critical_count == safepoint_id; 438 } 439 #endif 440 441 public: 442 enum { 443 is_definitely_current_thread = true 444 }; 445 446 // Constructor 447 Thread(); 448 virtual ~Thread() = 0; // Thread is abstract. 449 450 // Manage Thread::current() 451 void initialize_thread_current(); 452 static void clear_thread_current(); // TLS cleanup needed before threads terminate 453 454 protected: 455 // To be implemented by children. 456 virtual void run() = 0; 457 virtual void pre_run() = 0; 458 virtual void post_run() = 0; // Note: Thread must not be deleted prior to calling this! 459 460 #ifdef ASSERT 461 enum RunState { 462 PRE_CALL_RUN, 463 CALL_RUN, 464 PRE_RUN, 465 RUN, 466 POST_RUN 467 // POST_CALL_RUN - can't define this one as 'this' may be deleted when we want to set it 468 }; 469 RunState _run_state; // for lifecycle checks 470 #endif 471 472 473 public: 474 // invokes <ChildThreadClass>::run(), with common preparations and cleanups. 475 void call_run(); 476 477 // Testers 478 virtual bool is_VM_thread() const { return false; } 479 virtual bool is_Java_thread() const { return false; } 480 virtual bool is_Compiler_thread() const { return false; } 481 virtual bool is_Code_cache_sweeper_thread() const { return false; } 482 virtual bool is_service_thread() const { return false; } 483 virtual bool is_hidden_from_external_view() const { return false; } 484 virtual bool is_jvmti_agent_thread() const { return false; } 485 // True iff the thread can perform GC operations at a safepoint. 486 // Generally will be true only of VM thread and parallel GC WorkGang 487 // threads. 488 virtual bool is_GC_task_thread() const { return false; } 489 virtual bool is_Watcher_thread() const { return false; } 490 virtual bool is_ConcurrentGC_thread() const { return false; } 491 virtual bool is_Named_thread() const { return false; } 492 virtual bool is_Worker_thread() const { return false; } 493 494 // Can this thread make Java upcalls 495 virtual bool can_call_java() const { return false; } 496 497 // Is this a JavaThread that is on the VM's current ThreadsList? 498 // If so it must participate in the safepoint protocol. 499 virtual bool is_active_Java_thread() const { return false; } 500 501 // Casts 502 virtual WorkerThread* as_Worker_thread() const { return NULL; } 503 504 virtual char* name() const { return (char*)"Unknown thread"; } 505 506 // Returns the current thread (ASSERTS if NULL) 507 static inline Thread* current(); 508 // Returns the current thread, or NULL if not attached 509 static inline Thread* current_or_null(); 510 // Returns the current thread, or NULL if not attached, and is 511 // safe for use from signal-handlers 512 static inline Thread* current_or_null_safe(); 513 514 // Common thread operations 515 #ifdef ASSERT 516 static void check_for_dangling_thread_pointer(Thread *thread); 517 #endif 518 static void set_priority(Thread* thread, ThreadPriority priority); 519 static ThreadPriority get_priority(const Thread* const thread); 520 static void start(Thread* thread); 521 522 void set_native_thread_name(const char *name) { 523 assert(Thread::current() == this, "set_native_thread_name can only be called on the current thread"); 524 os::set_native_thread_name(name); 525 } 526 527 Monitor* SR_lock() const { return _SR_lock; } 528 529 bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; } 530 531 inline void set_suspend_flag(SuspendFlags f); 532 inline void clear_suspend_flag(SuspendFlags f); 533 534 inline void set_has_async_exception(); 535 inline void clear_has_async_exception(); 536 537 bool do_critical_native_unlock() const { return (_suspend_flags & _critical_native_unlock) != 0; } 538 539 inline void set_critical_native_unlock(); 540 inline void clear_critical_native_unlock(); 541 542 inline void set_trace_flag(); 543 inline void clear_trace_flag(); 544 545 inline void set_obj_deopt_flag(); 546 inline void clear_obj_deopt_flag(); 547 548 // Support for Unhandled Oop detection 549 // Add the field for both, fastdebug and debug, builds to keep 550 // Thread's fields layout the same. 551 // Note: CHECK_UNHANDLED_OOPS is defined only for fastdebug build. 552 #ifdef CHECK_UNHANDLED_OOPS 553 private: 554 UnhandledOops* _unhandled_oops; 555 #elif defined(ASSERT) 556 private: 557 void* _unhandled_oops; 558 #endif 559 #ifdef CHECK_UNHANDLED_OOPS 560 public: 561 UnhandledOops* unhandled_oops() { return _unhandled_oops; } 562 // Mark oop safe for gc. It may be stack allocated but won't move. 563 void allow_unhandled_oop(oop *op) { 564 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op); 565 } 566 // Clear oops at safepoint so crashes point to unhandled oop violator 567 void clear_unhandled_oops() { 568 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops(); 569 } 570 #endif // CHECK_UNHANDLED_OOPS 571 572 public: 573 #ifndef PRODUCT 574 bool skip_gcalot() { return _skip_gcalot; } 575 void set_skip_gcalot(bool v) { _skip_gcalot = v; } 576 #endif 577 578 // Installs a pending exception to be inserted later 579 static void send_async_exception(oop thread_oop, oop java_throwable); 580 581 // Resource area 582 ResourceArea* resource_area() const { return _resource_area; } 583 void set_resource_area(ResourceArea* area) { _resource_area = area; } 584 585 OSThread* osthread() const { return _osthread; } 586 void set_osthread(OSThread* thread) { _osthread = thread; } 587 588 // JNI handle support 589 JNIHandleBlock* active_handles() const { return _active_handles; } 590 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; } 591 JNIHandleBlock* free_handle_block() const { return _free_handle_block; } 592 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; } 593 594 // Internal handle support 595 HandleArea* handle_area() const { return _handle_area; } 596 void set_handle_area(HandleArea* area) { _handle_area = area; } 597 598 GrowableArray<Metadata*>* metadata_handles() const { return _metadata_handles; } 599 void set_metadata_handles(GrowableArray<Metadata*>* handles){ _metadata_handles = handles; } 600 601 // Thread-Local Allocation Buffer (TLAB) support 602 ThreadLocalAllocBuffer& tlab() { return _tlab; } 603 void initialize_tlab() { 604 if (UseTLAB) { 605 tlab().initialize(); 606 } 607 } 608 609 jlong allocated_bytes() { return _allocated_bytes; } 610 void set_allocated_bytes(jlong value) { _allocated_bytes = value; } 611 void incr_allocated_bytes(jlong size) { _allocated_bytes += size; } 612 inline jlong cooked_allocated_bytes(); 613 614 ThreadHeapSampler& heap_sampler() { return _heap_sampler; } 615 616 ThreadStatisticalInfo& statistical_info() { return _statistical_info; } 617 618 JFR_ONLY(DEFINE_THREAD_LOCAL_ACCESSOR_JFR;) 619 620 bool is_trace_suspend() { return (_suspend_flags & _trace_flag) != 0; } 621 622 bool is_obj_deopt_suspend() { return (_suspend_flags & _obj_deopt) != 0; } 623 624 // VM operation support 625 int vm_operation_ticket() { return ++_vm_operation_started_count; } 626 int vm_operation_completed_count() { return _vm_operation_completed_count; } 627 void increment_vm_operation_completed_count() { _vm_operation_completed_count++; } 628 629 // For tracking the heavyweight monitor the thread is pending on. 630 ObjectMonitor* current_pending_monitor() { 631 return _current_pending_monitor; 632 } 633 void set_current_pending_monitor(ObjectMonitor* monitor) { 634 _current_pending_monitor = monitor; 635 } 636 void set_current_pending_monitor_is_from_java(bool from_java) { 637 _current_pending_monitor_is_from_java = from_java; 638 } 639 bool current_pending_monitor_is_from_java() { 640 return _current_pending_monitor_is_from_java; 641 } 642 643 // For tracking the ObjectMonitor on which this thread called Object.wait() 644 ObjectMonitor* current_waiting_monitor() { 645 return _current_waiting_monitor; 646 } 647 void set_current_waiting_monitor(ObjectMonitor* monitor) { 648 _current_waiting_monitor = monitor; 649 } 650 651 // For tracking the Jvmti raw monitor the thread is pending on. 652 JvmtiRawMonitor* current_pending_raw_monitor() { 653 return _current_pending_raw_monitor; 654 } 655 void set_current_pending_raw_monitor(JvmtiRawMonitor* monitor) { 656 _current_pending_raw_monitor = monitor; 657 } 658 659 // GC support 660 // Apply "f->do_oop" to all root oops in "this". 661 // Used by JavaThread::oops_do. 662 // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames 663 virtual void oops_do(OopClosure* f, CodeBlobClosure* cf); 664 665 // Handles the parallel case for claim_threads_do. 666 private: 667 bool claim_par_threads_do(uintx claim_token); 668 public: 669 // Requires that "claim_token" is that of the current iteration. 670 // If "is_par" is false, sets the token of "this" to 671 // "claim_token", and returns "true". If "is_par" is true, 672 // uses an atomic instruction to set the current thread's token to 673 // "claim_token", if it is not already. Returns "true" iff the 674 // calling thread does the update, this indicates that the calling thread 675 // has claimed the thread in the current iteration. 676 bool claim_threads_do(bool is_par, uintx claim_token) { 677 if (!is_par) { 678 _threads_do_token = claim_token; 679 return true; 680 } else { 681 return claim_par_threads_do(claim_token); 682 } 683 } 684 685 uintx threads_do_token() const { return _threads_do_token; } 686 687 // jvmtiRedefineClasses support 688 void metadata_handles_do(void f(Metadata*)); 689 690 private: 691 // Check if address is within the given range of this thread's 692 // stack: stack_base() > adr >/>= limit 693 // The check is inclusive of limit if passed true, else exclusive. 694 bool is_in_stack_range(address adr, address limit, bool inclusive) const { 695 assert(stack_base() > limit && limit >= stack_end(), "limit is outside of stack"); 696 return stack_base() > adr && (inclusive ? adr >= limit : adr > limit); 697 } 698 699 public: 700 // Used by fast lock support 701 virtual bool is_lock_owned(address adr) const; 702 703 // Check if address is within the given range of this thread's 704 // stack: stack_base() > adr >= limit 705 bool is_in_stack_range_incl(address adr, address limit) const { 706 return is_in_stack_range(adr, limit, true); 707 } 708 709 // Check if address is within the given range of this thread's 710 // stack: stack_base() > adr > limit 711 bool is_in_stack_range_excl(address adr, address limit) const { 712 return is_in_stack_range(adr, limit, false); 713 } 714 715 // Check if address is in the stack mapped to this thread. Used mainly in 716 // error reporting (so has to include guard zone) and frame printing. 717 // Expects _stack_base to be initialized - checked with assert. 718 bool is_in_full_stack_checked(address adr) const { 719 return is_in_stack_range_incl(adr, stack_end()); 720 } 721 722 // Like is_in_full_stack_checked but without the assertions as this 723 // may be called in a thread before _stack_base is initialized. 724 bool is_in_full_stack(address adr) const { 725 address stack_end = _stack_base - _stack_size; 726 return _stack_base > adr && adr >= stack_end; 727 } 728 729 // Check if address is in the live stack of this thread (not just for locks). 730 // Warning: can only be called by the current thread on itself. 731 bool is_in_live_stack(address adr) const { 732 assert(Thread::current() == this, "is_in_live_stack can only be called from current thread"); 733 return is_in_stack_range_incl(adr, os::current_stack_pointer()); 734 } 735 736 // Sets this thread as starting thread. Returns failure if thread 737 // creation fails due to lack of memory, too many threads etc. 738 bool set_as_starting_thread(); 739 740 protected: 741 // OS data associated with the thread 742 OSThread* _osthread; // Platform-specific thread information 743 744 // Thread local resource area for temporary allocation within the VM 745 ResourceArea* _resource_area; 746 747 DEBUG_ONLY(ResourceMark* _current_resource_mark;) 748 749 // Thread local handle area for allocation of handles within the VM 750 HandleArea* _handle_area; 751 GrowableArray<Metadata*>* _metadata_handles; 752 753 // Support for stack overflow handling, get_thread, etc. 754 address _stack_base; 755 size_t _stack_size; 756 int _lgrp_id; 757 758 volatile void** polling_page_addr() { return &_polling_page; } 759 760 public: 761 // Stack overflow support 762 address stack_base() const { assert(_stack_base != NULL,"Sanity check"); return _stack_base; } 763 void set_stack_base(address base) { _stack_base = base; } 764 size_t stack_size() const { return _stack_size; } 765 void set_stack_size(size_t size) { _stack_size = size; } 766 address stack_end() const { return stack_base() - stack_size(); } 767 void record_stack_base_and_size(); 768 void register_thread_stack_with_NMT() NOT_NMT_RETURN; 769 770 int lgrp_id() const { return _lgrp_id; } 771 void set_lgrp_id(int value) { _lgrp_id = value; } 772 773 // Printing 774 void print_on(outputStream* st, bool print_extended_info) const; 775 virtual void print_on(outputStream* st) const { print_on(st, false); } 776 void print() const; 777 virtual void print_on_error(outputStream* st, char* buf, int buflen) const; 778 void print_value_on(outputStream* st) const; 779 780 // Debug-only code 781 #ifdef ASSERT 782 private: 783 // Deadlock detection support for Mutex locks. List of locks own by thread. 784 Mutex* _owned_locks; 785 // Mutex::set_owner_implementation is the only place where _owned_locks is modified, 786 // thus the friendship 787 friend class Mutex; 788 friend class Monitor; 789 790 public: 791 void print_owned_locks_on(outputStream* st) const; 792 void print_owned_locks() const { print_owned_locks_on(tty); } 793 Mutex* owned_locks() const { return _owned_locks; } 794 bool owns_locks() const { return owned_locks() != NULL; } 795 796 // Deadlock detection 797 ResourceMark* current_resource_mark() { return _current_resource_mark; } 798 void set_current_resource_mark(ResourceMark* rm) { _current_resource_mark = rm; } 799 #endif // ASSERT 800 801 // These functions check conditions on a JavaThread before possibly going to a safepoint, 802 // including NoSafepointVerifier. 803 void check_for_valid_safepoint_state() NOT_DEBUG_RETURN; 804 void check_possible_safepoint() NOT_DEBUG_RETURN; 805 806 private: 807 volatile int _jvmti_env_iteration_count; 808 809 public: 810 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; } 811 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; } 812 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; } 813 814 // Code generation 815 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file); } 816 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line); } 817 static ByteSize active_handles_offset() { return byte_offset_of(Thread, _active_handles); } 818 819 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base); } 820 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size); } 821 822 static ByteSize polling_page_offset() { return byte_offset_of(Thread, _polling_page); } 823 824 static ByteSize tlab_start_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::start_offset(); } 825 static ByteSize tlab_end_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::end_offset(); } 826 static ByteSize tlab_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::top_offset(); } 827 static ByteSize tlab_pf_top_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::pf_top_offset(); } 828 829 static ByteSize allocated_bytes_offset() { return byte_offset_of(Thread, _allocated_bytes); } 830 831 JFR_ONLY(DEFINE_THREAD_LOCAL_OFFSET_JFR;) 832 833 public: 834 volatile intptr_t _Stalled; 835 volatile int _TypeTag; 836 ParkEvent * _ParkEvent; // for Object monitors and JVMTI raw monitors 837 ParkEvent * _MuxEvent; // for low-level muxAcquire-muxRelease 838 int NativeSyncRecursion; // diagnostic 839 840 volatile int _OnTrap; // Resume-at IP delta 841 jint _hashStateW; // Marsaglia Shift-XOR thread-local RNG 842 jint _hashStateX; // thread-specific hashCode generator state 843 jint _hashStateY; 844 jint _hashStateZ; 845 846 // Low-level leaf-lock primitives used to implement synchronization 847 // and native monitor-mutex infrastructure. 848 // Not for general synchronization use. 849 static void SpinAcquire(volatile int * Lock, const char * Name); 850 static void SpinRelease(volatile int * Lock); 851 static void muxAcquire(volatile intptr_t * Lock, const char * Name); 852 static void muxRelease(volatile intptr_t * Lock); 853 }; 854 855 // Inline implementation of Thread::current() 856 inline Thread* Thread::current() { 857 Thread* current = current_or_null(); 858 assert(current != NULL, "Thread::current() called on detached thread"); 859 return current; 860 } 861 862 inline Thread* Thread::current_or_null() { 863 #ifndef USE_LIBRARY_BASED_TLS_ONLY 864 return _thr_current; 865 #else 866 if (ThreadLocalStorage::is_initialized()) { 867 return ThreadLocalStorage::thread(); 868 } 869 return NULL; 870 #endif 871 } 872 873 inline Thread* Thread::current_or_null_safe() { 874 if (ThreadLocalStorage::is_initialized()) { 875 return ThreadLocalStorage::thread(); 876 } 877 return NULL; 878 } 879 880 class NonJavaThread: public Thread { 881 friend class VMStructs; 882 883 NonJavaThread* volatile _next; 884 885 class List; 886 static List _the_list; 887 888 void add_to_the_list(); 889 void remove_from_the_list(); 890 891 protected: 892 virtual void pre_run(); 893 virtual void post_run(); 894 895 public: 896 NonJavaThread(); 897 ~NonJavaThread(); 898 899 class Iterator; 900 }; 901 902 // Provides iteration over the list of NonJavaThreads. 903 // List addition occurs in pre_run(), and removal occurs in post_run(), 904 // so that only live fully-initialized threads can be found in the list. 905 // Threads created after an iterator is constructed will not be visited 906 // by the iterator. The scope of an iterator is a critical section; there 907 // must be no safepoint checks in that scope. 908 class NonJavaThread::Iterator : public StackObj { 909 uint _protect_enter; 910 NonJavaThread* _current; 911 912 NONCOPYABLE(Iterator); 913 914 public: 915 Iterator(); 916 ~Iterator(); 917 918 bool end() const { return _current == NULL; } 919 NonJavaThread* current() const { return _current; } 920 void step(); 921 }; 922 923 // Name support for threads. non-JavaThread subclasses with multiple 924 // uniquely named instances should derive from this. 925 class NamedThread: public NonJavaThread { 926 friend class VMStructs; 927 enum { 928 max_name_len = 64 929 }; 930 private: 931 char* _name; 932 // log JavaThread being processed by oops_do 933 JavaThread* _processed_thread; 934 uint _gc_id; // The current GC id when a thread takes part in GC 935 936 public: 937 NamedThread(); 938 ~NamedThread(); 939 // May only be called once per thread. 940 void set_name(const char* format, ...) ATTRIBUTE_PRINTF(2, 3); 941 virtual bool is_Named_thread() const { return true; } 942 virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; } 943 JavaThread *processed_thread() { return _processed_thread; } 944 void set_processed_thread(JavaThread *thread) { _processed_thread = thread; } 945 virtual void print_on(outputStream* st) const; 946 947 void set_gc_id(uint gc_id) { _gc_id = gc_id; } 948 uint gc_id() { return _gc_id; } 949 }; 950 951 // Worker threads are named and have an id of an assigned work. 952 class WorkerThread: public NamedThread { 953 private: 954 uint _id; 955 public: 956 WorkerThread() : _id(0) { } 957 virtual bool is_Worker_thread() const { return true; } 958 959 virtual WorkerThread* as_Worker_thread() const { 960 assert(is_Worker_thread(), "Dubious cast to WorkerThread*?"); 961 return (WorkerThread*) this; 962 } 963 964 void set_id(uint work_id) { _id = work_id; } 965 uint id() const { return _id; } 966 }; 967 968 // A single WatcherThread is used for simulating timer interrupts. 969 class WatcherThread: public NonJavaThread { 970 friend class VMStructs; 971 protected: 972 virtual void run(); 973 974 private: 975 static WatcherThread* _watcher_thread; 976 977 static bool _startable; 978 // volatile due to at least one lock-free read 979 volatile static bool _should_terminate; 980 public: 981 enum SomeConstants { 982 delay_interval = 10 // interrupt delay in milliseconds 983 }; 984 985 // Constructor 986 WatcherThread(); 987 988 // No destruction allowed 989 ~WatcherThread() { 990 guarantee(false, "WatcherThread deletion must fix the race with VM termination"); 991 } 992 993 // Tester 994 bool is_Watcher_thread() const { return true; } 995 996 // Printing 997 char* name() const { return (char*)"VM Periodic Task Thread"; } 998 void print_on(outputStream* st) const; 999 void unpark(); 1000 1001 // Returns the single instance of WatcherThread 1002 static WatcherThread* watcher_thread() { return _watcher_thread; } 1003 1004 // Create and start the single instance of WatcherThread, or stop it on shutdown 1005 static void start(); 1006 static void stop(); 1007 // Only allow start once the VM is sufficiently initialized 1008 // Otherwise the first task to enroll will trigger the start 1009 static void make_startable(); 1010 private: 1011 int sleep() const; 1012 }; 1013 1014 1015 class CompilerThread; 1016 1017 typedef void (*ThreadFunction)(JavaThread*, TRAPS); 1018 1019 class JavaThread: public Thread { 1020 friend class VMStructs; 1021 friend class JVMCIVMStructs; 1022 friend class WhiteBox; 1023 friend class ThreadsSMRSupport; // to access _threadObj for exiting_threads_oops_do 1024 private: 1025 bool _on_thread_list; // Is set when this JavaThread is added to the Threads list 1026 oop _threadObj; // The Java level thread object 1027 1028 #ifdef ASSERT 1029 private: 1030 int _java_call_counter; 1031 1032 public: 1033 int java_call_counter() { return _java_call_counter; } 1034 void inc_java_call_counter() { _java_call_counter++; } 1035 void dec_java_call_counter() { 1036 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper"); 1037 _java_call_counter--; 1038 } 1039 private: // restore original namespace restriction 1040 #endif // ifdef ASSERT 1041 1042 #ifndef PRODUCT 1043 public: 1044 enum { 1045 jump_ring_buffer_size = 16 1046 }; 1047 private: // restore original namespace restriction 1048 #endif 1049 1050 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state 1051 1052 ThreadFunction _entry_point; 1053 1054 JNIEnv _jni_environment; 1055 1056 // Deopt support 1057 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization 1058 1059 CompiledMethod* _deopt_nmethod; // CompiledMethod that is currently being deoptimized 1060 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays 1061 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped 1062 // Holds updates by JVMTI agents for compiled frames that cannot be performed immediately. They 1063 // will be carried out as soon as possible, which, in most cases, is just before deoptimization of 1064 // the frame, when control returns to it. 1065 JvmtiDeferredUpdates* _jvmti_deferred_updates; 1066 1067 // Handshake value for fixing 6243940. We need a place for the i2c 1068 // adapter to store the callee Method*. This value is NEVER live 1069 // across a gc point so it does NOT have to be gc'd 1070 // The handshake is open ended since we can't be certain that it will 1071 // be NULLed. This is because we rarely ever see the race and end up 1072 // in handle_wrong_method which is the backend of the handshake. See 1073 // code in i2c adapters and handle_wrong_method. 1074 1075 Method* _callee_target; 1076 1077 // Used to pass back results to the interpreter or generated code running Java code. 1078 oop _vm_result; // oop result is GC-preserved 1079 Metadata* _vm_result_2; // non-oop result 1080 1081 // See ReduceInitialCardMarks: this holds the precise space interval of 1082 // the most recent slow path allocation for which compiled code has 1083 // elided card-marks for performance along the fast-path. 1084 MemRegion _deferred_card_mark; 1085 1086 MonitorChunk* _monitor_chunks; // Contains the off stack monitors 1087 // allocated during deoptimization 1088 // and by JNI_MonitorEnter/Exit 1089 1090 // Async. requests support 1091 enum AsyncRequests { 1092 _no_async_condition = 0, 1093 _async_exception, 1094 _async_unsafe_access_error 1095 }; 1096 AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request 1097 oop _pending_async_exception; 1098 1099 // Safepoint support 1100 public: // Expose _thread_state for SafeFetchInt() 1101 volatile JavaThreadState _thread_state; 1102 private: 1103 ThreadSafepointState* _safepoint_state; // Holds information about a thread during a safepoint 1104 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened 1105 1106 // JavaThread termination support 1107 enum TerminatedTypes { 1108 _not_terminated = 0xDEAD - 2, 1109 _thread_exiting, // JavaThread::exit() has been called for this thread 1110 _thread_terminated, // JavaThread is removed from thread list 1111 _vm_exited // JavaThread is still executing native code, but VM is terminated 1112 // only VM_Exit can set _vm_exited 1113 }; 1114 1115 // In general a JavaThread's _terminated field transitions as follows: 1116 // 1117 // _not_terminated => _thread_exiting => _thread_terminated 1118 // 1119 // _vm_exited is a special value to cover the case of a JavaThread 1120 // executing native code after the VM itself is terminated. 1121 volatile TerminatedTypes _terminated; 1122 // suspend/resume support 1123 volatile bool _suspend_equivalent; // Suspend equivalent condition 1124 jint _in_deopt_handler; // count of deoptimization 1125 // handlers thread is in 1126 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access 1127 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was 1128 // never locked) when throwing an exception. Used by interpreter only. 1129 1130 // JNI attach states: 1131 enum JNIAttachStates { 1132 _not_attaching_via_jni = 1, // thread is not attaching via JNI 1133 _attaching_via_jni, // thread is attaching via JNI 1134 _attached_via_jni // thread has attached via JNI 1135 }; 1136 1137 // A regular JavaThread's _jni_attach_state is _not_attaching_via_jni. 1138 // A native thread that is attaching via JNI starts with a value 1139 // of _attaching_via_jni and transitions to _attached_via_jni. 1140 volatile JNIAttachStates _jni_attach_state; 1141 1142 public: 1143 // State of the stack guard pages for this thread. 1144 enum StackGuardState { 1145 stack_guard_unused, // not needed 1146 stack_guard_reserved_disabled, 1147 stack_guard_yellow_reserved_disabled,// disabled (temporarily) after stack overflow 1148 stack_guard_enabled // enabled 1149 }; 1150 1151 private: 1152 1153 #if INCLUDE_JVMCI 1154 // The _pending_* fields below are used to communicate extra information 1155 // from an uncommon trap in JVMCI compiled code to the uncommon trap handler. 1156 1157 // Communicates the DeoptReason and DeoptAction of the uncommon trap 1158 int _pending_deoptimization; 1159 1160 // Specifies whether the uncommon trap is to bci 0 of a synchronized method 1161 // before the monitor has been acquired. 1162 bool _pending_monitorenter; 1163 1164 // Specifies if the DeoptReason for the last uncommon trap was Reason_transfer_to_interpreter 1165 bool _pending_transfer_to_interpreter; 1166 1167 // True if in a runtime call from compiled code that will deoptimize 1168 // and re-execute a failed heap allocation in the interpreter. 1169 bool _in_retryable_allocation; 1170 1171 // An id of a speculation that JVMCI compiled code can use to further describe and 1172 // uniquely identify the speculative optimization guarded by the uncommon trap 1173 jlong _pending_failed_speculation; 1174 1175 // These fields are mutually exclusive in terms of live ranges. 1176 union { 1177 // Communicates the pc at which the most recent implicit exception occurred 1178 // from the signal handler to a deoptimization stub. 1179 address _implicit_exception_pc; 1180 1181 // Communicates an alternative call target to an i2c stub from a JavaCall . 1182 address _alternate_call_target; 1183 } _jvmci; 1184 1185 // Support for high precision, thread sensitive counters in JVMCI compiled code. 1186 jlong* _jvmci_counters; 1187 1188 public: 1189 static jlong* _jvmci_old_thread_counters; 1190 static void collect_counters(jlong* array, int length); 1191 void resize_counters(int current_size, int new_size); 1192 static void resize_all_jvmci_counters(int new_size); 1193 1194 private: 1195 #endif // INCLUDE_JVMCI 1196 1197 StackGuardState _stack_guard_state; 1198 1199 // Precompute the limit of the stack as used in stack overflow checks. 1200 // We load it from here to simplify the stack overflow check in assembly. 1201 address _stack_overflow_limit; 1202 address _reserved_stack_activation; 1203 1204 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is 1205 // used to temp. parsing values into and out of the runtime system during exception handling for compiled 1206 // code) 1207 volatile oop _exception_oop; // Exception thrown in compiled code 1208 volatile address _exception_pc; // PC where exception happened 1209 volatile address _exception_handler_pc; // PC for handler of exception 1210 volatile int _is_method_handle_return; // true (== 1) if the current exception PC is a MethodHandle call site. 1211 1212 private: 1213 // support for JNI critical regions 1214 jint _jni_active_critical; // count of entries into JNI critical region 1215 1216 // Checked JNI: function name requires exception check 1217 char* _pending_jni_exception_check_fn; 1218 1219 // For deadlock detection. 1220 int _depth_first_number; 1221 1222 // JVMTI PopFrame support 1223 // This is set to popframe_pending to signal that top Java frame should be popped immediately 1224 int _popframe_condition; 1225 1226 // If reallocation of scalar replaced objects fails, we throw OOM 1227 // and during exception propagation, pop the top 1228 // _frames_to_pop_failed_realloc frames, the ones that reference 1229 // failed reallocations. 1230 int _frames_to_pop_failed_realloc; 1231 1232 friend class VMThread; 1233 friend class ThreadWaitTransition; 1234 friend class VM_Exit; 1235 1236 void initialize(); // Initialized the instance variables 1237 1238 public: 1239 // Constructor 1240 JavaThread(bool is_attaching_via_jni = false); // for main thread and JNI attached threads 1241 JavaThread(ThreadFunction entry_point, size_t stack_size = 0); 1242 ~JavaThread(); 1243 1244 #ifdef ASSERT 1245 // verify this JavaThread hasn't be published in the Threads::list yet 1246 void verify_not_published(); 1247 #endif // ASSERT 1248 1249 //JNI functiontable getter/setter for JVMTI jni function table interception API. 1250 void set_jni_functions(struct JNINativeInterface_* functionTable) { 1251 _jni_environment.functions = functionTable; 1252 } 1253 struct JNINativeInterface_* get_jni_functions() { 1254 return (struct JNINativeInterface_ *)_jni_environment.functions; 1255 } 1256 1257 // This function is called at thread creation to allow 1258 // platform specific thread variables to be initialized. 1259 void cache_global_variables(); 1260 1261 // Executes Shutdown.shutdown() 1262 void invoke_shutdown_hooks(); 1263 1264 // Cleanup on thread exit 1265 enum ExitType { 1266 normal_exit, 1267 jni_detach 1268 }; 1269 void exit(bool destroy_vm, ExitType exit_type = normal_exit); 1270 1271 void cleanup_failed_attach_current_thread(bool is_daemon); 1272 1273 // Testers 1274 virtual bool is_Java_thread() const { return true; } 1275 virtual bool can_call_java() const { return true; } 1276 1277 virtual bool is_active_Java_thread() const { 1278 return on_thread_list() && !is_terminated(); 1279 } 1280 1281 // Thread oop. threadObj() can be NULL for initial JavaThread 1282 // (or for threads attached via JNI) 1283 oop threadObj() const { return _threadObj; } 1284 void set_threadObj(oop p) { _threadObj = p; } 1285 1286 // Prepare thread and add to priority queue. If a priority is 1287 // not specified, use the priority of the thread object. Threads_lock 1288 // must be held while this function is called. 1289 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority); 1290 1291 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; } 1292 address saved_exception_pc() { return _saved_exception_pc; } 1293 1294 1295 ThreadFunction entry_point() const { return _entry_point; } 1296 1297 // Allocates a new Java level thread object for this thread. thread_name may be NULL. 1298 void allocate_threadObj(Handle thread_group, const char* thread_name, bool daemon, TRAPS); 1299 1300 // Last frame anchor routines 1301 1302 JavaFrameAnchor* frame_anchor(void) { return &_anchor; } 1303 1304 // last_Java_sp 1305 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); } 1306 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); } 1307 1308 // last_Java_pc 1309 1310 address last_Java_pc(void) { return _anchor.last_Java_pc(); } 1311 1312 // Safepoint support 1313 inline JavaThreadState thread_state() const; 1314 inline void set_thread_state(JavaThreadState s); 1315 inline void set_thread_state_fence(JavaThreadState s); // fence after setting thread state 1316 inline ThreadSafepointState* safepoint_state() const; 1317 inline void set_safepoint_state(ThreadSafepointState* state); 1318 inline bool is_at_poll_safepoint(); 1319 1320 // JavaThread termination and lifecycle support: 1321 void smr_delete(); 1322 bool on_thread_list() const { return _on_thread_list; } 1323 void set_on_thread_list() { _on_thread_list = true; } 1324 1325 // thread has called JavaThread::exit() or is terminated 1326 bool is_exiting() const; 1327 // thread is terminated (no longer on the threads list); we compare 1328 // against the two non-terminated values so that a freed JavaThread 1329 // will also be considered terminated. 1330 bool check_is_terminated(TerminatedTypes l_terminated) const { 1331 return l_terminated != _not_terminated && l_terminated != _thread_exiting; 1332 } 1333 bool is_terminated() const; 1334 void set_terminated(TerminatedTypes t); 1335 // special for Threads::remove() which is static: 1336 void set_terminated_value(); 1337 void block_if_vm_exited(); 1338 1339 bool doing_unsafe_access() { return _doing_unsafe_access; } 1340 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; } 1341 1342 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; } 1343 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; } 1344 1345 inline void set_polling_page_release(void* poll_value); 1346 inline void set_polling_page(void* poll_value); 1347 inline volatile void* get_polling_page(); 1348 1349 private: 1350 // Support for thread handshake operations 1351 HandshakeState _handshake; 1352 public: 1353 void set_handshake_operation(HandshakeOperation* op) { 1354 _handshake.set_operation(op); 1355 } 1356 1357 bool has_handshake() const { 1358 return _handshake.has_operation(); 1359 } 1360 1361 void handshake_process_by_self() { 1362 _handshake.process_by_self(); 1363 } 1364 1365 HandshakeState::ProcessResult handshake_try_process(HandshakeOperation* op) { 1366 return _handshake.try_process(op); 1367 } 1368 1369 #ifdef ASSERT 1370 Thread* active_handshaker() const { 1371 return _handshake.active_handshaker(); 1372 } 1373 #endif 1374 1375 // Suspend/resume support for JavaThread 1376 private: 1377 inline void set_ext_suspended(); 1378 inline void clear_ext_suspended(); 1379 1380 // Synchronize with another thread (most likely a JVMTI agent) that is deoptimizing objects of the 1381 // current thread, i.e. reverts optimizations based on escape analysis. 1382 void wait_for_object_deoptimization(); 1383 1384 public: 1385 void java_suspend(); // higher-level suspension logic called by the public APIs 1386 void java_resume(); // higher-level resume logic called by the public APIs 1387 int java_suspend_self(); // low-level self-suspension mechanics 1388 1389 private: 1390 // mid-level wrapper around java_suspend_self to set up correct state and 1391 // check for a pending safepoint at the end 1392 void java_suspend_self_with_safepoint_check(); 1393 1394 public: 1395 void check_and_wait_while_suspended() { 1396 assert(JavaThread::current() == this, "sanity check"); 1397 1398 bool do_self_suspend; 1399 do { 1400 // were we externally suspended while we were waiting? 1401 do_self_suspend = handle_special_suspend_equivalent_condition(); 1402 if (do_self_suspend) { 1403 // don't surprise the thread that suspended us by returning 1404 java_suspend_self(); 1405 set_suspend_equivalent(); 1406 } 1407 } while (do_self_suspend); 1408 } 1409 static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread); 1410 // Check for async exception in addition to safepoint and suspend request. 1411 static void check_special_condition_for_native_trans(JavaThread *thread); 1412 1413 // Same as check_special_condition_for_native_trans but finishes the 1414 // transition into thread_in_Java mode so that it can potentially 1415 // block. 1416 static void check_special_condition_for_native_trans_and_transition(JavaThread *thread); 1417 1418 bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits); 1419 bool is_ext_suspend_completed_with_lock(uint32_t *bits) { 1420 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1421 // Warning: is_ext_suspend_completed() may temporarily drop the 1422 // SR_lock to allow the thread to reach a stable thread state if 1423 // it is currently in a transient thread state. 1424 return is_ext_suspend_completed(false /* !called_by_wait */, 1425 SuspendRetryDelay, bits); 1426 } 1427 1428 // We cannot allow wait_for_ext_suspend_completion() to run forever or 1429 // we could hang. SuspendRetryCount and SuspendRetryDelay are normally 1430 // passed as the count and delay parameters. Experiments with specific 1431 // calls to wait_for_ext_suspend_completion() can be done by passing 1432 // other values in the code. Experiments with all calls can be done 1433 // via the appropriate -XX options. 1434 bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits); 1435 1436 // test for suspend - most (all?) of these should go away 1437 bool is_thread_fully_suspended(bool wait_for_suspend, uint32_t *bits); 1438 1439 inline void set_external_suspend(); 1440 inline void clear_external_suspend(); 1441 1442 bool is_external_suspend() const { 1443 return (_suspend_flags & _external_suspend) != 0; 1444 } 1445 // Whenever a thread transitions from native to vm/java it must suspend 1446 // if external|deopt suspend is present. 1447 bool is_suspend_after_native() const { 1448 return (_suspend_flags & (_external_suspend | _obj_deopt JFR_ONLY(| _trace_flag))) != 0; 1449 } 1450 1451 // external suspend request is completed 1452 bool is_ext_suspended() const { 1453 return (_suspend_flags & _ext_suspended) != 0; 1454 } 1455 1456 bool is_external_suspend_with_lock() const { 1457 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1458 return is_external_suspend(); 1459 } 1460 1461 // Special method to handle a pending external suspend request 1462 // when a suspend equivalent condition lifts. 1463 bool handle_special_suspend_equivalent_condition() { 1464 assert(is_suspend_equivalent(), 1465 "should only be called in a suspend equivalence condition"); 1466 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1467 bool ret = is_external_suspend(); 1468 if (!ret) { 1469 // not about to self-suspend so clear suspend equivalence 1470 clear_suspend_equivalent(); 1471 } 1472 // implied else: 1473 // We have a pending external suspend request so we leave the 1474 // suspend_equivalent flag set until java_suspend_self() sets 1475 // the ext_suspended flag and clears the suspend_equivalent 1476 // flag. This insures that wait_for_ext_suspend_completion() 1477 // will return consistent values. 1478 return ret; 1479 } 1480 1481 // utility methods to see if we are doing some kind of suspension 1482 bool is_being_ext_suspended() const { 1483 MutexLocker ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1484 return is_ext_suspended() || is_external_suspend(); 1485 } 1486 1487 bool is_suspend_equivalent() const { return _suspend_equivalent; } 1488 1489 void set_suspend_equivalent() { _suspend_equivalent = true; } 1490 void clear_suspend_equivalent() { _suspend_equivalent = false; } 1491 1492 // Thread.stop support 1493 void send_thread_stop(oop throwable); 1494 AsyncRequests clear_special_runtime_exit_condition() { 1495 AsyncRequests x = _special_runtime_exit_condition; 1496 _special_runtime_exit_condition = _no_async_condition; 1497 return x; 1498 } 1499 1500 // Are any async conditions present? 1501 bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); } 1502 1503 void check_and_handle_async_exceptions(bool check_unsafe_error = true); 1504 1505 // these next two are also used for self-suspension and async exception support 1506 void handle_special_runtime_exit_condition(bool check_asyncs = true); 1507 1508 // Return true if JavaThread has an asynchronous condition or 1509 // if external suspension is requested. 1510 bool has_special_runtime_exit_condition() { 1511 // Because we don't use is_external_suspend_with_lock 1512 // it is possible that we won't see an asynchronous external suspend 1513 // request that has just gotten started, i.e., SR_lock grabbed but 1514 // _external_suspend field change either not made yet or not visible 1515 // yet. However, this is okay because the request is asynchronous and 1516 // we will see the new flag value the next time through. It's also 1517 // possible that the external suspend request is dropped after 1518 // we have checked is_external_suspend(), we will recheck its value 1519 // under SR_lock in java_suspend_self(). 1520 return (_special_runtime_exit_condition != _no_async_condition) || 1521 is_external_suspend() || is_trace_suspend() || is_obj_deopt_suspend(); 1522 } 1523 1524 void set_pending_unsafe_access_error() { _special_runtime_exit_condition = _async_unsafe_access_error; } 1525 1526 inline void set_pending_async_exception(oop e); 1527 1528 // Fast-locking support 1529 bool is_lock_owned(address adr) const; 1530 1531 // Accessors for vframe array top 1532 // The linked list of vframe arrays are sorted on sp. This means when we 1533 // unpack the head must contain the vframe array to unpack. 1534 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; } 1535 vframeArray* vframe_array_head() const { return _vframe_array_head; } 1536 1537 // Side structure for deferring update of java frame locals until deopt occurs 1538 JvmtiDeferredUpdates* deferred_updates() const { return _jvmti_deferred_updates; } 1539 void set_deferred_updates(JvmtiDeferredUpdates* du) { _jvmti_deferred_updates = du; } 1540 1541 // These only really exist to make debugging deopt problems simpler 1542 1543 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; } 1544 vframeArray* vframe_array_last() const { return _vframe_array_last; } 1545 1546 // The special resourceMark used during deoptimization 1547 1548 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; } 1549 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; } 1550 1551 void set_deopt_compiled_method(CompiledMethod* nm) { _deopt_nmethod = nm; } 1552 CompiledMethod* deopt_compiled_method() { return _deopt_nmethod; } 1553 1554 Method* callee_target() const { return _callee_target; } 1555 void set_callee_target (Method* x) { _callee_target = x; } 1556 1557 // Oop results of vm runtime calls 1558 oop vm_result() const { return _vm_result; } 1559 void set_vm_result (oop x) { _vm_result = x; } 1560 1561 Metadata* vm_result_2() const { return _vm_result_2; } 1562 void set_vm_result_2 (Metadata* x) { _vm_result_2 = x; } 1563 1564 MemRegion deferred_card_mark() const { return _deferred_card_mark; } 1565 void set_deferred_card_mark(MemRegion mr) { _deferred_card_mark = mr; } 1566 1567 #if INCLUDE_JVMCI 1568 int pending_deoptimization() const { return _pending_deoptimization; } 1569 jlong pending_failed_speculation() const { return _pending_failed_speculation; } 1570 bool has_pending_monitorenter() const { return _pending_monitorenter; } 1571 void set_pending_monitorenter(bool b) { _pending_monitorenter = b; } 1572 void set_pending_deoptimization(int reason) { _pending_deoptimization = reason; } 1573 void set_pending_failed_speculation(jlong failed_speculation) { _pending_failed_speculation = failed_speculation; } 1574 void set_pending_transfer_to_interpreter(bool b) { _pending_transfer_to_interpreter = b; } 1575 void set_jvmci_alternate_call_target(address a) { assert(_jvmci._alternate_call_target == NULL, "must be"); _jvmci._alternate_call_target = a; } 1576 void set_jvmci_implicit_exception_pc(address a) { assert(_jvmci._implicit_exception_pc == NULL, "must be"); _jvmci._implicit_exception_pc = a; } 1577 1578 virtual bool in_retryable_allocation() const { return _in_retryable_allocation; } 1579 void set_in_retryable_allocation(bool b) { _in_retryable_allocation = b; } 1580 #endif // INCLUDE_JVMCI 1581 1582 // Exception handling for compiled methods 1583 oop exception_oop() const; 1584 address exception_pc() const { return _exception_pc; } 1585 address exception_handler_pc() const { return _exception_handler_pc; } 1586 bool is_method_handle_return() const { return _is_method_handle_return == 1; } 1587 1588 void set_exception_oop(oop o); 1589 void set_exception_pc(address a) { _exception_pc = a; } 1590 void set_exception_handler_pc(address a) { _exception_handler_pc = a; } 1591 void set_is_method_handle_return(bool value) { _is_method_handle_return = value ? 1 : 0; } 1592 1593 void clear_exception_oop_and_pc() { 1594 set_exception_oop(NULL); 1595 set_exception_pc(NULL); 1596 } 1597 1598 // Stack overflow support 1599 // 1600 // (small addresses) 1601 // 1602 // -- <-- stack_end() --- 1603 // | | 1604 // | red pages | 1605 // | | 1606 // -- <-- stack_red_zone_base() | 1607 // | | 1608 // | guard 1609 // | yellow pages zone 1610 // | | 1611 // | | 1612 // -- <-- stack_yellow_zone_base() | 1613 // | | 1614 // | | 1615 // | reserved pages | 1616 // | | 1617 // -- <-- stack_reserved_zone_base() --- --- 1618 // /|\ shadow <-- stack_overflow_limit() (somewhere in here) 1619 // | zone 1620 // \|/ size 1621 // some untouched memory --- 1622 // 1623 // 1624 // -- 1625 // | 1626 // | shadow zone 1627 // | 1628 // -- 1629 // x frame n 1630 // -- 1631 // x frame n-1 1632 // x 1633 // -- 1634 // ... 1635 // 1636 // -- 1637 // x frame 0 1638 // -- <-- stack_base() 1639 // 1640 // (large addresses) 1641 // 1642 1643 private: 1644 // These values are derived from flags StackRedPages, StackYellowPages, 1645 // StackReservedPages and StackShadowPages. The zone size is determined 1646 // ergonomically if page_size > 4K. 1647 static size_t _stack_red_zone_size; 1648 static size_t _stack_yellow_zone_size; 1649 static size_t _stack_reserved_zone_size; 1650 static size_t _stack_shadow_zone_size; 1651 public: 1652 inline size_t stack_available(address cur_sp); 1653 1654 static size_t stack_red_zone_size() { 1655 assert(_stack_red_zone_size > 0, "Don't call this before the field is initialized."); 1656 return _stack_red_zone_size; 1657 } 1658 static void set_stack_red_zone_size(size_t s) { 1659 assert(is_aligned(s, os::vm_page_size()), 1660 "We can not protect if the red zone size is not page aligned."); 1661 assert(_stack_red_zone_size == 0, "This should be called only once."); 1662 _stack_red_zone_size = s; 1663 } 1664 address stack_red_zone_base() { 1665 return (address)(stack_end() + stack_red_zone_size()); 1666 } 1667 bool in_stack_red_zone(address a) { 1668 return a <= stack_red_zone_base() && a >= stack_end(); 1669 } 1670 1671 static size_t stack_yellow_zone_size() { 1672 assert(_stack_yellow_zone_size > 0, "Don't call this before the field is initialized."); 1673 return _stack_yellow_zone_size; 1674 } 1675 static void set_stack_yellow_zone_size(size_t s) { 1676 assert(is_aligned(s, os::vm_page_size()), 1677 "We can not protect if the yellow zone size is not page aligned."); 1678 assert(_stack_yellow_zone_size == 0, "This should be called only once."); 1679 _stack_yellow_zone_size = s; 1680 } 1681 1682 static size_t stack_reserved_zone_size() { 1683 // _stack_reserved_zone_size may be 0. This indicates the feature is off. 1684 return _stack_reserved_zone_size; 1685 } 1686 static void set_stack_reserved_zone_size(size_t s) { 1687 assert(is_aligned(s, os::vm_page_size()), 1688 "We can not protect if the reserved zone size is not page aligned."); 1689 assert(_stack_reserved_zone_size == 0, "This should be called only once."); 1690 _stack_reserved_zone_size = s; 1691 } 1692 address stack_reserved_zone_base() const { 1693 return (address)(stack_end() + 1694 (stack_red_zone_size() + stack_yellow_zone_size() + stack_reserved_zone_size())); 1695 } 1696 bool in_stack_reserved_zone(address a) { 1697 return (a <= stack_reserved_zone_base()) && 1698 (a >= (address)((intptr_t)stack_reserved_zone_base() - stack_reserved_zone_size())); 1699 } 1700 1701 static size_t stack_yellow_reserved_zone_size() { 1702 return _stack_yellow_zone_size + _stack_reserved_zone_size; 1703 } 1704 bool in_stack_yellow_reserved_zone(address a) { 1705 return (a <= stack_reserved_zone_base()) && (a >= stack_red_zone_base()); 1706 } 1707 1708 // Size of red + yellow + reserved zones. 1709 static size_t stack_guard_zone_size() { 1710 return stack_red_zone_size() + stack_yellow_reserved_zone_size(); 1711 } 1712 1713 static size_t stack_shadow_zone_size() { 1714 assert(_stack_shadow_zone_size > 0, "Don't call this before the field is initialized."); 1715 return _stack_shadow_zone_size; 1716 } 1717 static void set_stack_shadow_zone_size(size_t s) { 1718 // The shadow area is not allocated or protected, so 1719 // it needs not be page aligned. 1720 // But the stack bang currently assumes that it is a 1721 // multiple of page size. This guarantees that the bang 1722 // loop touches all pages in the shadow zone. 1723 // This can be guaranteed differently, as well. E.g., if 1724 // the page size is a multiple of 4K, banging in 4K steps 1725 // suffices to touch all pages. (Some pages are banged 1726 // several times, though.) 1727 assert(is_aligned(s, os::vm_page_size()), 1728 "Stack bang assumes multiple of page size."); 1729 assert(_stack_shadow_zone_size == 0, "This should be called only once."); 1730 _stack_shadow_zone_size = s; 1731 } 1732 1733 void create_stack_guard_pages(); 1734 void remove_stack_guard_pages(); 1735 1736 void enable_stack_reserved_zone(); 1737 void disable_stack_reserved_zone(); 1738 void enable_stack_yellow_reserved_zone(); 1739 void disable_stack_yellow_reserved_zone(); 1740 void enable_stack_red_zone(); 1741 void disable_stack_red_zone(); 1742 1743 inline bool stack_guard_zone_unused(); 1744 inline bool stack_yellow_reserved_zone_disabled(); 1745 inline bool stack_reserved_zone_disabled(); 1746 inline bool stack_guards_enabled(); 1747 1748 address reserved_stack_activation() const { return _reserved_stack_activation; } 1749 void set_reserved_stack_activation(address addr) { 1750 assert(_reserved_stack_activation == stack_base() 1751 || _reserved_stack_activation == NULL 1752 || addr == stack_base(), "Must not be set twice"); 1753 _reserved_stack_activation = addr; 1754 } 1755 1756 // Attempt to reguard the stack after a stack overflow may have occurred. 1757 // Returns true if (a) guard pages are not needed on this thread, (b) the 1758 // pages are already guarded, or (c) the pages were successfully reguarded. 1759 // Returns false if there is not enough stack space to reguard the pages, in 1760 // which case the caller should unwind a frame and try again. The argument 1761 // should be the caller's (approximate) sp. 1762 bool reguard_stack(address cur_sp); 1763 // Similar to above but see if current stackpoint is out of the guard area 1764 // and reguard if possible. 1765 bool reguard_stack(void); 1766 1767 address stack_overflow_limit() { return _stack_overflow_limit; } 1768 void set_stack_overflow_limit() { 1769 _stack_overflow_limit = 1770 stack_end() + MAX2(JavaThread::stack_guard_zone_size(), JavaThread::stack_shadow_zone_size()); 1771 } 1772 1773 // Check if address is in the usable part of the stack (excludes protected 1774 // guard pages). Can be applied to any thread and is an approximation for 1775 // using is_in_live_stack when the query has to happen from another thread. 1776 bool is_in_usable_stack(address adr) const { 1777 return is_in_stack_range_incl(adr, stack_reserved_zone_base()); 1778 } 1779 1780 // Misc. accessors/mutators 1781 void set_do_not_unlock(void) { _do_not_unlock_if_synchronized = true; } 1782 void clr_do_not_unlock(void) { _do_not_unlock_if_synchronized = false; } 1783 bool do_not_unlock(void) { return _do_not_unlock_if_synchronized; } 1784 1785 // For assembly stub generation 1786 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj); } 1787 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment); } 1788 static ByteSize pending_jni_exception_check_fn_offset() { 1789 return byte_offset_of(JavaThread, _pending_jni_exception_check_fn); 1790 } 1791 static ByteSize last_Java_sp_offset() { 1792 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset(); 1793 } 1794 static ByteSize last_Java_pc_offset() { 1795 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset(); 1796 } 1797 static ByteSize frame_anchor_offset() { 1798 return byte_offset_of(JavaThread, _anchor); 1799 } 1800 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target); } 1801 static ByteSize vm_result_offset() { return byte_offset_of(JavaThread, _vm_result); } 1802 static ByteSize vm_result_2_offset() { return byte_offset_of(JavaThread, _vm_result_2); } 1803 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state); } 1804 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc); } 1805 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread); } 1806 #if INCLUDE_JVMCI 1807 static ByteSize pending_deoptimization_offset() { return byte_offset_of(JavaThread, _pending_deoptimization); } 1808 static ByteSize pending_monitorenter_offset() { return byte_offset_of(JavaThread, _pending_monitorenter); } 1809 static ByteSize pending_failed_speculation_offset() { return byte_offset_of(JavaThread, _pending_failed_speculation); } 1810 static ByteSize jvmci_alternate_call_target_offset() { return byte_offset_of(JavaThread, _jvmci._alternate_call_target); } 1811 static ByteSize jvmci_implicit_exception_pc_offset() { return byte_offset_of(JavaThread, _jvmci._implicit_exception_pc); } 1812 static ByteSize jvmci_counters_offset() { return byte_offset_of(JavaThread, _jvmci_counters); } 1813 #endif // INCLUDE_JVMCI 1814 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop); } 1815 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc); } 1816 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); } 1817 static ByteSize stack_overflow_limit_offset() { return byte_offset_of(JavaThread, _stack_overflow_limit); } 1818 static ByteSize is_method_handle_return_offset() { return byte_offset_of(JavaThread, _is_method_handle_return); } 1819 static ByteSize stack_guard_state_offset() { return byte_offset_of(JavaThread, _stack_guard_state); } 1820 static ByteSize reserved_stack_activation_offset() { return byte_offset_of(JavaThread, _reserved_stack_activation); } 1821 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags); } 1822 1823 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); } 1824 static ByteSize should_post_on_exceptions_flag_offset() { 1825 return byte_offset_of(JavaThread, _should_post_on_exceptions_flag); 1826 } 1827 static ByteSize doing_unsafe_access_offset() { return byte_offset_of(JavaThread, _doing_unsafe_access); } 1828 1829 // Returns the jni environment for this thread 1830 JNIEnv* jni_environment() { return &_jni_environment; } 1831 1832 static JavaThread* thread_from_jni_environment(JNIEnv* env) { 1833 JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset())); 1834 // Only return NULL if thread is off the thread list; starting to 1835 // exit should not return NULL. 1836 if (thread_from_jni_env->is_terminated()) { 1837 thread_from_jni_env->block_if_vm_exited(); 1838 return NULL; 1839 } else { 1840 return thread_from_jni_env; 1841 } 1842 } 1843 1844 // JNI critical regions. These can nest. 1845 bool in_critical() { return _jni_active_critical > 0; } 1846 bool in_last_critical() { return _jni_active_critical == 1; } 1847 inline void enter_critical(); 1848 void exit_critical() { 1849 assert(Thread::current() == this, "this must be current thread"); 1850 _jni_active_critical--; 1851 assert(_jni_active_critical >= 0, "JNI critical nesting problem?"); 1852 } 1853 1854 // Checked JNI: is the programmer required to check for exceptions, if so specify 1855 // which function name. Returning to a Java frame should implicitly clear the 1856 // pending check, this is done for Native->Java transitions (i.e. user JNI code). 1857 // VM->Java transistions are not cleared, it is expected that JNI code enclosed 1858 // within ThreadToNativeFromVM makes proper exception checks (i.e. VM internal). 1859 bool is_pending_jni_exception_check() const { return _pending_jni_exception_check_fn != NULL; } 1860 void clear_pending_jni_exception_check() { _pending_jni_exception_check_fn = NULL; } 1861 const char* get_pending_jni_exception_check() const { return _pending_jni_exception_check_fn; } 1862 void set_pending_jni_exception_check(const char* fn_name) { _pending_jni_exception_check_fn = (char*) fn_name; } 1863 1864 // For deadlock detection 1865 int depth_first_number() { return _depth_first_number; } 1866 void set_depth_first_number(int dfn) { _depth_first_number = dfn; } 1867 1868 private: 1869 void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; } 1870 1871 public: 1872 MonitorChunk* monitor_chunks() const { return _monitor_chunks; } 1873 void add_monitor_chunk(MonitorChunk* chunk); 1874 void remove_monitor_chunk(MonitorChunk* chunk); 1875 bool in_deopt_handler() const { return _in_deopt_handler > 0; } 1876 void inc_in_deopt_handler() { _in_deopt_handler++; } 1877 void dec_in_deopt_handler() { 1878 assert(_in_deopt_handler > 0, "mismatched deopt nesting"); 1879 if (_in_deopt_handler > 0) { // robustness 1880 _in_deopt_handler--; 1881 } 1882 } 1883 1884 private: 1885 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; } 1886 1887 public: 1888 1889 // Frame iteration; calls the function f for all frames on the stack 1890 void frames_do(void f(frame*, const RegisterMap*)); 1891 1892 // Memory operations 1893 void oops_do(OopClosure* f, CodeBlobClosure* cf); 1894 1895 // Sweeper operations 1896 virtual void nmethods_do(CodeBlobClosure* cf); 1897 1898 // RedefineClasses Support 1899 void metadata_do(MetadataClosure* f); 1900 1901 // Debug method asserting thread states are correct during a handshake operation. 1902 DEBUG_ONLY(void verify_states_for_handshake();) 1903 1904 // Misc. operations 1905 char* name() const { return (char*)get_thread_name(); } 1906 void print_on(outputStream* st, bool print_extended_info) const; 1907 void print_on(outputStream* st) const { print_on(st, false); } 1908 void print() const; 1909 void print_thread_state_on(outputStream*) const PRODUCT_RETURN; 1910 void print_on_error(outputStream* st, char* buf, int buflen) const; 1911 void print_name_on_error(outputStream* st, char* buf, int buflen) const; 1912 void verify(); 1913 const char* get_thread_name() const; 1914 protected: 1915 // factor out low-level mechanics for use in both normal and error cases 1916 virtual const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const; 1917 public: 1918 // Accessing frames 1919 frame last_frame() { 1920 _anchor.make_walkable(this); 1921 return pd_last_frame(); 1922 } 1923 javaVFrame* last_java_vframe(RegisterMap* reg_map); 1924 1925 // Returns method at 'depth' java or native frames down the stack 1926 // Used for security checks 1927 Klass* security_get_caller_class(int depth); 1928 1929 // Print stack trace in external format 1930 void print_stack_on(outputStream* st); 1931 void print_stack() { print_stack_on(tty); } 1932 1933 // Print stack traces in various internal formats 1934 void trace_stack() PRODUCT_RETURN; 1935 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN; 1936 void trace_frames() PRODUCT_RETURN; 1937 1938 // Print an annotated view of the stack frames 1939 void print_frame_layout(int depth = 0, bool validate_only = false) NOT_DEBUG_RETURN; 1940 void validate_frame_layout() { 1941 print_frame_layout(0, true); 1942 } 1943 1944 // Function for testing deoptimization 1945 void deoptimize(); 1946 void make_zombies(); 1947 1948 void deoptimize_marked_methods(); 1949 1950 public: 1951 // Returns the running thread as a JavaThread 1952 static inline JavaThread* current(); 1953 1954 // Returns the active Java thread. Do not use this if you know you are calling 1955 // from a JavaThread, as it's slower than JavaThread::current. If called from 1956 // the VMThread, it also returns the JavaThread that instigated the VMThread's 1957 // operation. You may not want that either. 1958 static JavaThread* active(); 1959 1960 inline CompilerThread* as_CompilerThread(); 1961 1962 protected: 1963 virtual void pre_run(); 1964 virtual void run(); 1965 void thread_main_inner(); 1966 virtual void post_run(); 1967 1968 1969 private: 1970 GrowableArray<oop>* _array_for_gc; 1971 public: 1972 1973 void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; } 1974 1975 public: 1976 // Thread local information maintained by JVMTI. 1977 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; } 1978 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state() 1979 // getter is used to get this JavaThread's JvmtiThreadState if it has 1980 // one which means NULL can be returned. JvmtiThreadState::state_for() 1981 // is used to get the specified JavaThread's JvmtiThreadState if it has 1982 // one or it allocates a new JvmtiThreadState for the JavaThread and 1983 // returns it. JvmtiThreadState::state_for() will return NULL only if 1984 // the specified JavaThread is exiting. 1985 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; } 1986 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); } 1987 1988 // JVMTI PopFrame support 1989 // Setting and clearing popframe_condition 1990 // All of these enumerated values are bits. popframe_pending 1991 // indicates that a PopFrame() has been requested and not yet been 1992 // completed. popframe_processing indicates that that PopFrame() is in 1993 // the process of being completed. popframe_force_deopt_reexecution_bit 1994 // indicates that special handling is required when returning to a 1995 // deoptimized caller. 1996 enum PopCondition { 1997 popframe_inactive = 0x00, 1998 popframe_pending_bit = 0x01, 1999 popframe_processing_bit = 0x02, 2000 popframe_force_deopt_reexecution_bit = 0x04 2001 }; 2002 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; } 2003 void set_popframe_condition(PopCondition c) { _popframe_condition = c; } 2004 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; } 2005 void clear_popframe_condition() { _popframe_condition = popframe_inactive; } 2006 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); } 2007 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; } 2008 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; } 2009 void clear_popframe_forcing_deopt_reexecution() { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; } 2010 2011 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); } 2012 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; } 2013 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; } 2014 2015 int frames_to_pop_failed_realloc() const { return _frames_to_pop_failed_realloc; } 2016 void set_frames_to_pop_failed_realloc(int nb) { _frames_to_pop_failed_realloc = nb; } 2017 void dec_frames_to_pop_failed_realloc() { _frames_to_pop_failed_realloc--; } 2018 2019 private: 2020 // Saved incoming arguments to popped frame. 2021 // Used only when popped interpreted frame returns to deoptimized frame. 2022 void* _popframe_preserved_args; 2023 int _popframe_preserved_args_size; 2024 2025 public: 2026 void popframe_preserve_args(ByteSize size_in_bytes, void* start); 2027 void* popframe_preserved_args(); 2028 ByteSize popframe_preserved_args_size(); 2029 WordSize popframe_preserved_args_size_in_words(); 2030 void popframe_free_preserved_args(); 2031 2032 2033 private: 2034 JvmtiThreadState *_jvmti_thread_state; 2035 2036 // Used by the interpreter in fullspeed mode for frame pop, method 2037 // entry, method exit and single stepping support. This field is 2038 // only set to non-zero at a safepoint or using a direct handshake 2039 // (see EnterInterpOnlyModeClosure). 2040 // It can be set to zero asynchronously to this threads execution (i.e., without 2041 // safepoint/handshake or a lock) so we have to be very careful. 2042 // Accesses by other threads are synchronized using JvmtiThreadState_lock though. 2043 int _interp_only_mode; 2044 2045 public: 2046 // used by the interpreter for fullspeed debugging support (see above) 2047 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); } 2048 bool is_interp_only_mode() { return (_interp_only_mode != 0); } 2049 int get_interp_only_mode() { return _interp_only_mode; } 2050 void increment_interp_only_mode() { ++_interp_only_mode; } 2051 void decrement_interp_only_mode() { --_interp_only_mode; } 2052 2053 // support for cached flag that indicates whether exceptions need to be posted for this thread 2054 // if this is false, we can avoid deoptimizing when events are thrown 2055 // this gets set to reflect whether jvmtiExport::post_exception_throw would actually do anything 2056 private: 2057 int _should_post_on_exceptions_flag; 2058 2059 public: 2060 int should_post_on_exceptions_flag() { return _should_post_on_exceptions_flag; } 2061 void set_should_post_on_exceptions_flag(int val) { _should_post_on_exceptions_flag = val; } 2062 2063 private: 2064 ThreadStatistics *_thread_stat; 2065 2066 public: 2067 ThreadStatistics* get_thread_stat() const { return _thread_stat; } 2068 2069 // Return a blocker object for which this thread is blocked parking. 2070 oop current_park_blocker(); 2071 2072 private: 2073 static size_t _stack_size_at_create; 2074 2075 public: 2076 static inline size_t stack_size_at_create(void) { 2077 return _stack_size_at_create; 2078 } 2079 static inline void set_stack_size_at_create(size_t value) { 2080 _stack_size_at_create = value; 2081 } 2082 2083 // Machine dependent stuff 2084 #include OS_CPU_HEADER(thread) 2085 2086 // JSR166 per-thread parker 2087 private: 2088 Parker* _parker; 2089 public: 2090 Parker* parker() { return _parker; } 2091 2092 // Biased locking support 2093 private: 2094 GrowableArray<MonitorInfo*>* _cached_monitor_info; 2095 public: 2096 GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; } 2097 void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; } 2098 2099 // clearing/querying jni attach status 2100 bool is_attaching_via_jni() const { return _jni_attach_state == _attaching_via_jni; } 2101 bool has_attached_via_jni() const { return is_attaching_via_jni() || _jni_attach_state == _attached_via_jni; } 2102 inline void set_done_attaching_via_jni(); 2103 2104 // Stack dump assistance: 2105 // Track the class we want to initialize but for which we have to wait 2106 // on its init_lock() because it is already being initialized. 2107 void set_class_to_be_initialized(InstanceKlass* k); 2108 InstanceKlass* class_to_be_initialized() const; 2109 2110 private: 2111 InstanceKlass* _class_to_be_initialized; 2112 2113 // java.lang.Thread.sleep support 2114 ParkEvent * _SleepEvent; 2115 public: 2116 bool sleep(jlong millis); 2117 2118 // java.lang.Thread interruption support 2119 void interrupt(); 2120 bool is_interrupted(bool clear_interrupted); 2121 2122 }; 2123 2124 // Inline implementation of JavaThread::current 2125 inline JavaThread* JavaThread::current() { 2126 Thread* thread = Thread::current(); 2127 assert(thread->is_Java_thread(), "just checking"); 2128 return (JavaThread*)thread; 2129 } 2130 2131 inline CompilerThread* JavaThread::as_CompilerThread() { 2132 assert(is_Compiler_thread(), "just checking"); 2133 return (CompilerThread*)this; 2134 } 2135 2136 // Dedicated thread to sweep the code cache 2137 class CodeCacheSweeperThread : public JavaThread { 2138 CompiledMethod* _scanned_compiled_method; // nmethod being scanned by the sweeper 2139 public: 2140 CodeCacheSweeperThread(); 2141 // Track the nmethod currently being scanned by the sweeper 2142 void set_scanned_compiled_method(CompiledMethod* cm) { 2143 assert(_scanned_compiled_method == NULL || cm == NULL, "should reset to NULL before writing a new value"); 2144 _scanned_compiled_method = cm; 2145 } 2146 2147 // Hide sweeper thread from external view. 2148 bool is_hidden_from_external_view() const { return true; } 2149 2150 bool is_Code_cache_sweeper_thread() const { return true; } 2151 2152 // Prevent GC from unloading _scanned_compiled_method 2153 void oops_do(OopClosure* f, CodeBlobClosure* cf); 2154 void nmethods_do(CodeBlobClosure* cf); 2155 }; 2156 2157 // A thread used for Compilation. 2158 class CompilerThread : public JavaThread { 2159 friend class VMStructs; 2160 private: 2161 CompilerCounters* _counters; 2162 2163 ciEnv* _env; 2164 CompileLog* _log; 2165 CompileTask* volatile _task; // print_threads_compiling can read this concurrently. 2166 CompileQueue* _queue; 2167 BufferBlob* _buffer_blob; 2168 2169 AbstractCompiler* _compiler; 2170 TimeStamp _idle_time; 2171 2172 public: 2173 2174 static CompilerThread* current(); 2175 2176 CompilerThread(CompileQueue* queue, CompilerCounters* counters); 2177 ~CompilerThread(); 2178 2179 bool is_Compiler_thread() const { return true; } 2180 2181 virtual bool can_call_java() const; 2182 2183 // Hide native compiler threads from external view. 2184 bool is_hidden_from_external_view() const { return !can_call_java(); } 2185 2186 void set_compiler(AbstractCompiler* c) { _compiler = c; } 2187 AbstractCompiler* compiler() const { return _compiler; } 2188 2189 CompileQueue* queue() const { return _queue; } 2190 CompilerCounters* counters() const { return _counters; } 2191 2192 // Get/set the thread's compilation environment. 2193 ciEnv* env() { return _env; } 2194 void set_env(ciEnv* env) { _env = env; } 2195 2196 BufferBlob* get_buffer_blob() const { return _buffer_blob; } 2197 void set_buffer_blob(BufferBlob* b) { _buffer_blob = b; } 2198 2199 // Get/set the thread's logging information 2200 CompileLog* log() { return _log; } 2201 void init_log(CompileLog* log) { 2202 // Set once, for good. 2203 assert(_log == NULL, "set only once"); 2204 _log = log; 2205 } 2206 2207 void start_idle_timer() { _idle_time.update(); } 2208 jlong idle_time_millis() { 2209 return TimeHelper::counter_to_millis(_idle_time.ticks_since_update()); 2210 } 2211 2212 #ifndef PRODUCT 2213 private: 2214 IdealGraphPrinter *_ideal_graph_printer; 2215 public: 2216 IdealGraphPrinter *ideal_graph_printer() { return _ideal_graph_printer; } 2217 void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; } 2218 #endif 2219 2220 // Get/set the thread's current task 2221 CompileTask* task() { return _task; } 2222 void set_task(CompileTask* task) { _task = task; } 2223 }; 2224 2225 inline CompilerThread* CompilerThread::current() { 2226 return JavaThread::current()->as_CompilerThread(); 2227 } 2228 2229 // The active thread queue. It also keeps track of the current used 2230 // thread priorities. 2231 class Threads: AllStatic { 2232 friend class VMStructs; 2233 private: 2234 static int _number_of_threads; 2235 static int _number_of_non_daemon_threads; 2236 static int _return_code; 2237 static uintx _thread_claim_token; 2238 #ifdef ASSERT 2239 static bool _vm_complete; 2240 #endif 2241 2242 static void initialize_java_lang_classes(JavaThread* main_thread, TRAPS); 2243 static void initialize_jsr292_core_classes(TRAPS); 2244 2245 public: 2246 // Thread management 2247 // force_daemon is a concession to JNI, where we may need to add a 2248 // thread to the thread list before allocating its thread object 2249 static void add(JavaThread* p, bool force_daemon = false); 2250 static void remove(JavaThread* p, bool is_daemon); 2251 static void non_java_threads_do(ThreadClosure* tc); 2252 static void java_threads_do(ThreadClosure* tc); 2253 static void java_threads_and_vm_thread_do(ThreadClosure* tc); 2254 static void threads_do(ThreadClosure* tc); 2255 static void possibly_parallel_threads_do(bool is_par, ThreadClosure* tc); 2256 2257 // Initializes the vm and creates the vm thread 2258 static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain); 2259 static void convert_vm_init_libraries_to_agents(); 2260 static void create_vm_init_libraries(); 2261 static void create_vm_init_agents(); 2262 static void shutdown_vm_agents(); 2263 static bool destroy_vm(); 2264 // Supported VM versions via JNI 2265 // Includes JNI_VERSION_1_1 2266 static jboolean is_supported_jni_version_including_1_1(jint version); 2267 // Does not include JNI_VERSION_1_1 2268 static jboolean is_supported_jni_version(jint version); 2269 2270 // The "thread claim token" provides a way for threads to be claimed 2271 // by parallel worker tasks. 2272 // 2273 // Each thread contains a "token" field. A task will claim the 2274 // thread only if its token is different from the global token, 2275 // which is updated by calling change_thread_claim_token(). When 2276 // a thread is claimed, it's token is set to the global token value 2277 // so other threads in the same iteration pass won't claim it. 2278 // 2279 // For this to work change_thread_claim_token() needs to be called 2280 // exactly once in sequential code before starting parallel tasks 2281 // that should claim threads. 2282 // 2283 // New threads get their token set to 0 and change_thread_claim_token() 2284 // never sets the global token to 0. 2285 static uintx thread_claim_token() { return _thread_claim_token; } 2286 static void change_thread_claim_token(); 2287 static void assert_all_threads_claimed() NOT_DEBUG_RETURN; 2288 2289 // Apply "f->do_oop" to all root oops in all threads. 2290 // This version may only be called by sequential code. 2291 static void oops_do(OopClosure* f, CodeBlobClosure* cf); 2292 // This version may be called by sequential or parallel code. 2293 static void possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf); 2294 2295 // Sweeper 2296 static void nmethods_do(CodeBlobClosure* cf); 2297 2298 // RedefineClasses support 2299 static void metadata_do(MetadataClosure* f); 2300 static void metadata_handles_do(void f(Metadata*)); 2301 2302 #ifdef ASSERT 2303 static bool is_vm_complete() { return _vm_complete; } 2304 #endif // ASSERT 2305 2306 // Verification 2307 static void verify(); 2308 static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks, bool print_extended_info); 2309 static void print(bool print_stacks, bool internal_format) { 2310 // this function is only used by debug.cpp 2311 print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */, false /* simple format */); 2312 } 2313 static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen); 2314 static void print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf, 2315 int buflen, bool* found_current); 2316 static void print_threads_compiling(outputStream* st, char* buf, int buflen, bool short_form = false); 2317 2318 // Get Java threads that are waiting to enter a monitor. 2319 static GrowableArray<JavaThread*>* get_pending_threads(ThreadsList * t_list, 2320 int count, address monitor); 2321 2322 // Get owning Java thread from the monitor's owner field. 2323 static JavaThread *owning_thread_from_monitor_owner(ThreadsList * t_list, 2324 address owner); 2325 2326 // Number of threads on the active threads list 2327 static int number_of_threads() { return _number_of_threads; } 2328 // Number of non-daemon threads on the active threads list 2329 static int number_of_non_daemon_threads() { return _number_of_non_daemon_threads; } 2330 2331 // Deoptimizes all frames tied to marked nmethods 2332 static void deoptimized_wrt_marked_nmethods(); 2333 2334 struct Test; // For private gtest access. 2335 }; 2336 2337 class SignalHandlerMark: public StackObj { 2338 private: 2339 Thread* _thread; 2340 public: 2341 SignalHandlerMark(Thread* t) { 2342 _thread = t; 2343 if (_thread) _thread->enter_signal_handler(); 2344 } 2345 ~SignalHandlerMark() { 2346 if (_thread) _thread->leave_signal_handler(); 2347 _thread = NULL; 2348 } 2349 }; 2350 2351 2352 #endif // SHARE_RUNTIME_THREAD_HPP