1 /* 2 * Copyright 1997-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 class ThreadSafepointState; 26 class ThreadProfiler; 27 28 class JvmtiThreadState; 29 class JvmtiGetLoadedClassesClosure; 30 class ThreadStatistics; 31 class ConcurrentLocksDump; 32 class ParkEvent ; 33 34 class ciEnv; 35 class CompileThread; 36 class CompileLog; 37 class CompileTask; 38 class CompileQueue; 39 class CompilerCounters; 40 class vframeArray; 41 42 class DeoptResourceMark; 43 class jvmtiDeferredLocalVariableSet; 44 45 class GCTaskQueue; 46 class ThreadClosure; 47 class IdealGraphPrinter; 48 49 // Class hierarchy 50 // - Thread 51 // - VMThread 52 // - JavaThread 53 // - WatcherThread 54 55 class Thread: public ThreadShadow { 56 friend class VMStructs; 57 private: 58 // Exception handling 59 // (Note: _pending_exception and friends are in ThreadShadow) 60 //oop _pending_exception; // pending exception for current thread 61 // const char* _exception_file; // file information for exception (debugging only) 62 // int _exception_line; // line information for exception (debugging only) 63 64 // Support for forcing alignment of thread objects for biased locking 65 void* _real_malloc_address; 66 public: 67 void* operator new(size_t size); 68 void operator delete(void* p); 69 private: 70 71 // *************************************************************** 72 // Suspend and resume support 73 // *************************************************************** 74 // 75 // VM suspend/resume no longer exists - it was once used for various 76 // things including safepoints but was deprecated and finally removed 77 // in Java 7. Because VM suspension was considered "internal" Java-level 78 // suspension was considered "external", and this legacy naming scheme 79 // remains. 80 // 81 // External suspend/resume requests come from JVM_SuspendThread, 82 // JVM_ResumeThread, JVMTI SuspendThread, and finally JVMTI 83 // ResumeThread. External 84 // suspend requests cause _external_suspend to be set and external 85 // resume requests cause _external_suspend to be cleared. 86 // External suspend requests do not nest on top of other external 87 // suspend requests. The higher level APIs reject suspend requests 88 // for already suspended threads. 89 // 90 // The external_suspend 91 // flag is checked by has_special_runtime_exit_condition() and java thread 92 // will self-suspend when handle_special_runtime_exit_condition() is 93 // called. Most uses of the _thread_blocked state in JavaThreads are 94 // considered the same as being externally suspended; if the blocking 95 // condition lifts, the JavaThread will self-suspend. Other places 96 // where VM checks for external_suspend include: 97 // + mutex granting (do not enter monitors when thread is suspended) 98 // + state transitions from _thread_in_native 99 // 100 // In general, java_suspend() does not wait for an external suspend 101 // request to complete. When it returns, the only guarantee is that 102 // the _external_suspend field is true. 103 // 104 // wait_for_ext_suspend_completion() is used to wait for an external 105 // suspend request to complete. External suspend requests are usually 106 // followed by some other interface call that requires the thread to 107 // be quiescent, e.g., GetCallTrace(). By moving the "wait time" into 108 // the interface that requires quiescence, we give the JavaThread a 109 // chance to self-suspend before we need it to be quiescent. This 110 // improves overall suspend/query performance. 111 // 112 // _suspend_flags controls the behavior of java_ suspend/resume. 113 // It must be set under the protection of SR_lock. Read from the flag is 114 // OK without SR_lock as long as the value is only used as a hint. 115 // (e.g., check _external_suspend first without lock and then recheck 116 // inside SR_lock and finish the suspension) 117 // 118 // _suspend_flags is also overloaded for other "special conditions" so 119 // that a single check indicates whether any special action is needed 120 // eg. for async exceptions. 121 // ------------------------------------------------------------------- 122 // Notes: 123 // 1. The suspend/resume logic no longer uses ThreadState in OSThread 124 // but we still update its value to keep other part of the system (mainly 125 // JVMTI) happy. ThreadState is legacy code (see notes in 126 // osThread.hpp). 127 // 128 // 2. It would be more natural if set_external_suspend() is private and 129 // part of java_suspend(), but that probably would affect the suspend/query 130 // performance. Need more investigation on this. 131 // 132 133 // suspend/resume lock: used for self-suspend 134 Monitor* _SR_lock; 135 136 protected: 137 enum SuspendFlags { 138 // NOTE: avoid using the sign-bit as cc generates different test code 139 // when the sign-bit is used, and sometimes incorrectly - see CR 6398077 140 141 _external_suspend = 0x20000000U, // thread is asked to self suspend 142 _ext_suspended = 0x40000000U, // thread has self-suspended 143 _deopt_suspend = 0x10000000U, // thread needs to self suspend for deopt 144 145 _has_async_exception = 0x00000001U // there is a pending async exception 146 }; 147 148 // various suspension related flags - atomically updated 149 // overloaded for async exception checking in check_special_condition_for_native_trans. 150 volatile uint32_t _suspend_flags; 151 152 private: 153 int _num_nested_signal; 154 155 public: 156 void enter_signal_handler() { _num_nested_signal++; } 157 void leave_signal_handler() { _num_nested_signal--; } 158 bool is_inside_signal_handler() const { return _num_nested_signal > 0; } 159 160 private: 161 // Debug tracing 162 static void trace(const char* msg, const Thread* const thread) PRODUCT_RETURN; 163 164 // Active_handles points to a block of handles 165 JNIHandleBlock* _active_handles; 166 167 // One-element thread local free list 168 JNIHandleBlock* _free_handle_block; 169 170 // Point to the last handle mark 171 HandleMark* _last_handle_mark; 172 173 // The parity of the last strong_roots iteration in which this thread was 174 // claimed as a task. 175 jint _oops_do_parity; 176 177 public: 178 void set_last_handle_mark(HandleMark* mark) { _last_handle_mark = mark; } 179 HandleMark* last_handle_mark() const { return _last_handle_mark; } 180 private: 181 182 // debug support for checking if code does allow safepoints or not 183 // GC points in the VM can happen because of allocation, invoking a VM operation, or blocking on 184 // mutex, or blocking on an object synchronizer (Java locking). 185 // If !allow_safepoint(), then an assertion failure will happen in any of the above cases 186 // If !allow_allocation(), then an assertion failure will happen during allocation 187 // (Hence, !allow_safepoint() => !allow_allocation()). 188 // 189 // The two classes No_Safepoint_Verifier and No_Allocation_Verifier are used to set these counters. 190 // 191 NOT_PRODUCT(int _allow_safepoint_count;) // If 0, thread allow a safepoint to happen 192 debug_only (int _allow_allocation_count;) // If 0, the thread is allowed to allocate oops. 193 194 // Used by SkipGCALot class. 195 NOT_PRODUCT(bool _skip_gcalot;) // Should we elide gc-a-lot? 196 197 // Record when GC is locked out via the GC_locker mechanism 198 CHECK_UNHANDLED_OOPS_ONLY(int _gc_locked_out_count;) 199 200 friend class No_Alloc_Verifier; 201 friend class No_Safepoint_Verifier; 202 friend class Pause_No_Safepoint_Verifier; 203 friend class ThreadLocalStorage; 204 friend class GC_locker; 205 206 ThreadLocalAllocBuffer _tlab; // Thread-local eden 207 208 int _vm_operation_started_count; // VM_Operation support 209 int _vm_operation_completed_count; // VM_Operation support 210 211 ObjectMonitor* _current_pending_monitor; // ObjectMonitor this thread 212 // is waiting to lock 213 bool _current_pending_monitor_is_from_java; // locking is from Java code 214 215 // ObjectMonitor on which this thread called Object.wait() 216 ObjectMonitor* _current_waiting_monitor; 217 218 // Private thread-local objectmonitor list - a simple cache organized as a SLL. 219 public: 220 ObjectMonitor * omFreeList ; 221 int omFreeCount ; // length of omFreeList 222 int omFreeProvision ; // reload chunk size 223 224 public: 225 enum { 226 is_definitely_current_thread = true 227 }; 228 229 // Constructor 230 Thread(); 231 virtual ~Thread(); 232 233 // initializtion 234 void initialize_thread_local_storage(); 235 236 // thread entry point 237 virtual void run(); 238 239 // Testers 240 virtual bool is_VM_thread() const { return false; } 241 virtual bool is_Java_thread() const { return false; } 242 // Remove this ifdef when C1 is ported to the compiler interface. 243 virtual bool is_Compiler_thread() const { return false; } 244 virtual bool is_hidden_from_external_view() const { return false; } 245 virtual bool is_jvmti_agent_thread() const { return false; } 246 // True iff the thread can perform GC operations at a safepoint. 247 // Generally will be true only of VM thread and parallel GC WorkGang 248 // threads. 249 virtual bool is_GC_task_thread() const { return false; } 250 virtual bool is_Watcher_thread() const { return false; } 251 virtual bool is_ConcurrentGC_thread() const { return false; } 252 253 virtual char* name() const { return (char*)"Unknown thread"; } 254 255 // Returns the current thread 256 static inline Thread* current(); 257 258 // Common thread operations 259 static void set_priority(Thread* thread, ThreadPriority priority); 260 static ThreadPriority get_priority(const Thread* const thread); 261 static void start(Thread* thread); 262 static void interrupt(Thread* thr); 263 static bool is_interrupted(Thread* thr, bool clear_interrupted); 264 265 Monitor* SR_lock() const { return _SR_lock; } 266 267 bool has_async_exception() const { return (_suspend_flags & _has_async_exception) != 0; } 268 269 void set_suspend_flag(SuspendFlags f) { 270 assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch"); 271 uint32_t flags; 272 do { 273 flags = _suspend_flags; 274 } 275 while (Atomic::cmpxchg((jint)(flags | f), 276 (volatile jint*)&_suspend_flags, 277 (jint)flags) != (jint)flags); 278 } 279 void clear_suspend_flag(SuspendFlags f) { 280 assert(sizeof(jint) == sizeof(_suspend_flags), "size mismatch"); 281 uint32_t flags; 282 do { 283 flags = _suspend_flags; 284 } 285 while (Atomic::cmpxchg((jint)(flags & ~f), 286 (volatile jint*)&_suspend_flags, 287 (jint)flags) != (jint)flags); 288 } 289 290 void set_has_async_exception() { 291 set_suspend_flag(_has_async_exception); 292 } 293 void clear_has_async_exception() { 294 clear_suspend_flag(_has_async_exception); 295 } 296 297 // Support for Unhandled Oop detection 298 #ifdef CHECK_UNHANDLED_OOPS 299 private: 300 UnhandledOops *_unhandled_oops; 301 public: 302 UnhandledOops* unhandled_oops() { return _unhandled_oops; } 303 // Mark oop safe for gc. It may be stack allocated but won't move. 304 void allow_unhandled_oop(oop *op) { 305 if (CheckUnhandledOops) unhandled_oops()->allow_unhandled_oop(op); 306 } 307 // Clear oops at safepoint so crashes point to unhandled oop violator 308 void clear_unhandled_oops() { 309 if (CheckUnhandledOops) unhandled_oops()->clear_unhandled_oops(); 310 } 311 bool is_gc_locked_out() { return _gc_locked_out_count > 0; } 312 #endif // CHECK_UNHANDLED_OOPS 313 314 #ifndef PRODUCT 315 bool skip_gcalot() { return _skip_gcalot; } 316 void set_skip_gcalot(bool v) { _skip_gcalot = v; } 317 #endif 318 319 public: 320 // Installs a pending exception to be inserted later 321 static void send_async_exception(oop thread_oop, oop java_throwable); 322 323 // Resource area 324 ResourceArea* resource_area() const { return _resource_area; } 325 void set_resource_area(ResourceArea* area) { _resource_area = area; } 326 327 OSThread* osthread() const { return _osthread; } 328 void set_osthread(OSThread* thread) { _osthread = thread; } 329 330 // JNI handle support 331 JNIHandleBlock* active_handles() const { return _active_handles; } 332 void set_active_handles(JNIHandleBlock* block) { _active_handles = block; } 333 JNIHandleBlock* free_handle_block() const { return _free_handle_block; } 334 void set_free_handle_block(JNIHandleBlock* block) { _free_handle_block = block; } 335 336 // Internal handle support 337 HandleArea* handle_area() const { return _handle_area; } 338 void set_handle_area(HandleArea* area) { _handle_area = area; } 339 340 // Thread-Local Allocation Buffer (TLAB) support 341 ThreadLocalAllocBuffer& tlab() { return _tlab; } 342 void initialize_tlab() { 343 if (UseTLAB) { 344 tlab().initialize(); 345 } 346 } 347 348 // VM operation support 349 int vm_operation_ticket() { return ++_vm_operation_started_count; } 350 int vm_operation_completed_count() { return _vm_operation_completed_count; } 351 void increment_vm_operation_completed_count() { _vm_operation_completed_count++; } 352 353 // For tracking the heavyweight monitor the thread is pending on. 354 ObjectMonitor* current_pending_monitor() { 355 return _current_pending_monitor; 356 } 357 void set_current_pending_monitor(ObjectMonitor* monitor) { 358 _current_pending_monitor = monitor; 359 } 360 void set_current_pending_monitor_is_from_java(bool from_java) { 361 _current_pending_monitor_is_from_java = from_java; 362 } 363 bool current_pending_monitor_is_from_java() { 364 return _current_pending_monitor_is_from_java; 365 } 366 367 // For tracking the ObjectMonitor on which this thread called Object.wait() 368 ObjectMonitor* current_waiting_monitor() { 369 return _current_waiting_monitor; 370 } 371 void set_current_waiting_monitor(ObjectMonitor* monitor) { 372 _current_waiting_monitor = monitor; 373 } 374 375 // GC support 376 // Apply "f->do_oop" to all root oops in "this". 377 // Apply "cf->do_code_blob" (if !NULL) to all code blobs active in frames 378 void oops_do(OopClosure* f, CodeBlobClosure* cf); 379 380 // Handles the parallel case for the method below. 381 private: 382 bool claim_oops_do_par_case(int collection_parity); 383 public: 384 // Requires that "collection_parity" is that of the current strong roots 385 // iteration. If "is_par" is false, sets the parity of "this" to 386 // "collection_parity", and returns "true". If "is_par" is true, 387 // uses an atomic instruction to set the current threads parity to 388 // "collection_parity", if it is not already. Returns "true" iff the 389 // calling thread does the update, this indicates that the calling thread 390 // has claimed the thread's stack as a root groop in the current 391 // collection. 392 bool claim_oops_do(bool is_par, int collection_parity) { 393 if (!is_par) { 394 _oops_do_parity = collection_parity; 395 return true; 396 } else { 397 return claim_oops_do_par_case(collection_parity); 398 } 399 } 400 401 // Sweeper support 402 void nmethods_do(CodeBlobClosure* cf); 403 404 // Tells if adr belong to this thread. This is used 405 // for checking if a lock is owned by the running thread. 406 407 // Used by fast lock support 408 virtual bool is_lock_owned(address adr) const; 409 410 // Check if address is in the stack of the thread (not just for locks). 411 // Warning: the method can only be used on the running thread 412 bool is_in_stack(address adr) const; 413 414 // Sets this thread as starting thread. Returns failure if thread 415 // creation fails due to lack of memory, too many threads etc. 416 bool set_as_starting_thread(); 417 418 protected: 419 // OS data associated with the thread 420 OSThread* _osthread; // Platform-specific thread information 421 422 // Thread local resource area for temporary allocation within the VM 423 ResourceArea* _resource_area; 424 425 // Thread local handle area for allocation of handles within the VM 426 HandleArea* _handle_area; 427 428 // Support for stack overflow handling, get_thread, etc. 429 address _stack_base; 430 size_t _stack_size; 431 uintptr_t _self_raw_id; // used by get_thread (mutable) 432 int _lgrp_id; 433 434 public: 435 // Stack overflow support 436 address stack_base() const { assert(_stack_base != NULL,"Sanity check"); return _stack_base; } 437 438 void set_stack_base(address base) { _stack_base = base; } 439 size_t stack_size() const { return _stack_size; } 440 void set_stack_size(size_t size) { _stack_size = size; } 441 void record_stack_base_and_size(); 442 443 int lgrp_id() const { return _lgrp_id; } 444 void set_lgrp_id(int value) { _lgrp_id = value; } 445 446 // Printing 447 void print_on(outputStream* st) const; 448 void print() const { print_on(tty); } 449 virtual void print_on_error(outputStream* st, char* buf, int buflen) const; 450 451 // Debug-only code 452 453 #ifdef ASSERT 454 private: 455 // Deadlock detection support for Mutex locks. List of locks own by thread. 456 Monitor *_owned_locks; 457 // Mutex::set_owner_implementation is the only place where _owned_locks is modified, 458 // thus the friendship 459 friend class Mutex; 460 friend class Monitor; 461 462 public: 463 void print_owned_locks_on(outputStream* st) const; 464 void print_owned_locks() const { print_owned_locks_on(tty); } 465 Monitor * owned_locks() const { return _owned_locks; } 466 bool owns_locks() const { return owned_locks() != NULL; } 467 bool owns_locks_but_compiled_lock() const; 468 469 // Deadlock detection 470 bool allow_allocation() { return _allow_allocation_count == 0; } 471 #endif 472 473 void check_for_valid_safepoint_state(bool potential_vm_operation) PRODUCT_RETURN; 474 475 private: 476 volatile int _jvmti_env_iteration_count; 477 478 public: 479 void entering_jvmti_env_iteration() { ++_jvmti_env_iteration_count; } 480 void leaving_jvmti_env_iteration() { --_jvmti_env_iteration_count; } 481 bool is_inside_jvmti_env_iteration() { return _jvmti_env_iteration_count > 0; } 482 483 // Code generation 484 static ByteSize exception_file_offset() { return byte_offset_of(Thread, _exception_file ); } 485 static ByteSize exception_line_offset() { return byte_offset_of(Thread, _exception_line ); } 486 static ByteSize active_handles_offset() { return byte_offset_of(Thread, _active_handles ); } 487 488 static ByteSize stack_base_offset() { return byte_offset_of(Thread, _stack_base ); } 489 static ByteSize stack_size_offset() { return byte_offset_of(Thread, _stack_size ); } 490 static ByteSize omFreeList_offset() { return byte_offset_of(Thread, omFreeList); } 491 492 #define TLAB_FIELD_OFFSET(name) \ 493 static ByteSize tlab_##name##_offset() { return byte_offset_of(Thread, _tlab) + ThreadLocalAllocBuffer::name##_offset(); } 494 495 TLAB_FIELD_OFFSET(start) 496 TLAB_FIELD_OFFSET(end) 497 TLAB_FIELD_OFFSET(top) 498 TLAB_FIELD_OFFSET(pf_top) 499 TLAB_FIELD_OFFSET(size) // desired_size 500 TLAB_FIELD_OFFSET(refill_waste_limit) 501 TLAB_FIELD_OFFSET(number_of_refills) 502 TLAB_FIELD_OFFSET(fast_refill_waste) 503 TLAB_FIELD_OFFSET(slow_allocations) 504 505 #undef TLAB_FIELD_OFFSET 506 507 public: 508 volatile intptr_t _Stalled ; 509 volatile int _TypeTag ; 510 ParkEvent * _ParkEvent ; // for synchronized() 511 ParkEvent * _SleepEvent ; // for Thread.sleep 512 ParkEvent * _MutexEvent ; // for native internal Mutex/Monitor 513 ParkEvent * _MuxEvent ; // for low-level muxAcquire-muxRelease 514 int NativeSyncRecursion ; // diagnostic 515 516 volatile int _OnTrap ; // Resume-at IP delta 517 jint _hashStateW ; // Marsaglia Shift-XOR thread-local RNG 518 jint _hashStateX ; // thread-specific hashCode generator state 519 jint _hashStateY ; 520 jint _hashStateZ ; 521 void * _schedctl ; 522 523 intptr_t _ScratchA, _ScratchB ; // Scratch locations for fast-path sync code 524 static ByteSize ScratchA_offset() { return byte_offset_of(Thread, _ScratchA ); } 525 static ByteSize ScratchB_offset() { return byte_offset_of(Thread, _ScratchB ); } 526 527 volatile jint rng [4] ; // RNG for spin loop 528 529 // Low-level leaf-lock primitives used to implement synchronization 530 // and native monitor-mutex infrastructure. 531 // Not for general synchronization use. 532 static void SpinAcquire (volatile int * Lock, const char * Name) ; 533 static void SpinRelease (volatile int * Lock) ; 534 static void muxAcquire (volatile intptr_t * Lock, const char * Name) ; 535 static void muxAcquireW (volatile intptr_t * Lock, ParkEvent * ev) ; 536 static void muxRelease (volatile intptr_t * Lock) ; 537 538 }; 539 540 // Inline implementation of Thread::current() 541 // Thread::current is "hot" it's called > 128K times in the 1st 500 msecs of 542 // startup. 543 // ThreadLocalStorage::thread is warm -- it's called > 16K times in the same 544 // period. This is inlined in thread_<os_family>.inline.hpp. 545 546 inline Thread* Thread::current() { 547 #ifdef ASSERT 548 // This function is very high traffic. Define PARANOID to enable expensive 549 // asserts. 550 #ifdef PARANOID 551 // Signal handler should call ThreadLocalStorage::get_thread_slow() 552 Thread* t = ThreadLocalStorage::get_thread_slow(); 553 assert(t != NULL && !t->is_inside_signal_handler(), 554 "Don't use Thread::current() inside signal handler"); 555 #endif 556 #endif 557 Thread* thread = ThreadLocalStorage::thread(); 558 assert(thread != NULL, "just checking"); 559 return thread; 560 } 561 562 // Name support for threads. non-JavaThread subclasses with multiple 563 // uniquely named instances should derive from this. 564 class NamedThread: public Thread { 565 friend class VMStructs; 566 enum { 567 max_name_len = 64 568 }; 569 private: 570 char* _name; 571 public: 572 NamedThread(); 573 ~NamedThread(); 574 // May only be called once per thread. 575 void set_name(const char* format, ...); 576 virtual char* name() const { return _name == NULL ? (char*)"Unknown Thread" : _name; } 577 }; 578 579 // Worker threads are named and have an id of an assigned work. 580 class WorkerThread: public NamedThread { 581 private: 582 uint _id; 583 public: 584 WorkerThread() : _id(0) { } 585 void set_id(uint work_id) { _id = work_id; } 586 uint id() const { return _id; } 587 }; 588 589 // A single WatcherThread is used for simulating timer interrupts. 590 class WatcherThread: public Thread { 591 friend class VMStructs; 592 public: 593 virtual void run(); 594 595 private: 596 static WatcherThread* _watcher_thread; 597 598 static bool _should_terminate; 599 public: 600 enum SomeConstants { 601 delay_interval = 10 // interrupt delay in milliseconds 602 }; 603 604 // Constructor 605 WatcherThread(); 606 607 // Tester 608 bool is_Watcher_thread() const { return true; } 609 610 // Printing 611 char* name() const { return (char*)"VM Periodic Task Thread"; } 612 void print_on(outputStream* st) const; 613 void print() const { print_on(tty); } 614 615 // Returns the single instance of WatcherThread 616 static WatcherThread* watcher_thread() { return _watcher_thread; } 617 618 // Create and start the single instance of WatcherThread, or stop it on shutdown 619 static void start(); 620 static void stop(); 621 }; 622 623 624 class CompilerThread; 625 626 typedef void (*ThreadFunction)(JavaThread*, TRAPS); 627 628 class JavaThread: public Thread { 629 friend class VMStructs; 630 private: 631 JavaThread* _next; // The next thread in the Threads list 632 oop _threadObj; // The Java level thread object 633 634 #ifdef ASSERT 635 private: 636 int _java_call_counter; 637 638 public: 639 int java_call_counter() { return _java_call_counter; } 640 void inc_java_call_counter() { _java_call_counter++; } 641 void dec_java_call_counter() { 642 assert(_java_call_counter > 0, "Invalid nesting of JavaCallWrapper"); 643 _java_call_counter--; 644 } 645 private: // restore original namespace restriction 646 #endif // ifdef ASSERT 647 648 #ifndef PRODUCT 649 public: 650 enum { 651 jump_ring_buffer_size = 16 652 }; 653 private: // restore original namespace restriction 654 #endif 655 656 JavaFrameAnchor _anchor; // Encapsulation of current java frame and it state 657 658 ThreadFunction _entry_point; 659 660 JNIEnv _jni_environment; 661 662 // Deopt support 663 DeoptResourceMark* _deopt_mark; // Holds special ResourceMark for deoptimization 664 665 intptr_t* _must_deopt_id; // id of frame that needs to be deopted once we 666 // transition out of native 667 668 vframeArray* _vframe_array_head; // Holds the heap of the active vframeArrays 669 vframeArray* _vframe_array_last; // Holds last vFrameArray we popped 670 // Because deoptimization is lazy we must save jvmti requests to set locals 671 // in compiled frames until we deoptimize and we have an interpreter frame. 672 // This holds the pointer to array (yeah like there might be more than one) of 673 // description of compiled vframes that have locals that need to be updated. 674 GrowableArray<jvmtiDeferredLocalVariableSet*>* _deferred_locals_updates; 675 676 // Handshake value for fixing 6243940. We need a place for the i2c 677 // adapter to store the callee methodOop. This value is NEVER live 678 // across a gc point so it does NOT have to be gc'd 679 // The handshake is open ended since we can't be certain that it will 680 // be NULLed. This is because we rarely ever see the race and end up 681 // in handle_wrong_method which is the backend of the handshake. See 682 // code in i2c adapters and handle_wrong_method. 683 684 methodOop _callee_target; 685 686 // Oop results of VM runtime calls 687 oop _vm_result; // Used to pass back an oop result into Java code, GC-preserved 688 oop _vm_result_2; // Used to pass back an oop result into Java code, GC-preserved 689 690 // See ReduceInitialCardMarks: this holds the precise space interval of 691 // the most recent slow path allocation for which compiled code has 692 // elided card-marks for performance along the fast-path. 693 MemRegion _deferred_card_mark; 694 695 MonitorChunk* _monitor_chunks; // Contains the off stack monitors 696 // allocated during deoptimization 697 // and by JNI_MonitorEnter/Exit 698 699 // Async. requests support 700 enum AsyncRequests { 701 _no_async_condition = 0, 702 _async_exception, 703 _async_unsafe_access_error 704 }; 705 AsyncRequests _special_runtime_exit_condition; // Enum indicating pending async. request 706 oop _pending_async_exception; 707 708 // Safepoint support 709 public: // Expose _thread_state for SafeFetchInt() 710 volatile JavaThreadState _thread_state; 711 private: 712 ThreadSafepointState *_safepoint_state; // Holds information about a thread during a safepoint 713 address _saved_exception_pc; // Saved pc of instruction where last implicit exception happened 714 715 // JavaThread termination support 716 enum TerminatedTypes { 717 _not_terminated = 0xDEAD - 2, 718 _thread_exiting, // JavaThread::exit() has been called for this thread 719 _thread_terminated, // JavaThread is removed from thread list 720 _vm_exited // JavaThread is still executing native code, but VM is terminated 721 // only VM_Exit can set _vm_exited 722 }; 723 724 // In general a JavaThread's _terminated field transitions as follows: 725 // 726 // _not_terminated => _thread_exiting => _thread_terminated 727 // 728 // _vm_exited is a special value to cover the case of a JavaThread 729 // executing native code after the VM itself is terminated. 730 TerminatedTypes _terminated; 731 // suspend/resume support 732 volatile bool _suspend_equivalent; // Suspend equivalent condition 733 jint _in_deopt_handler; // count of deoptimization 734 // handlers thread is in 735 volatile bool _doing_unsafe_access; // Thread may fault due to unsafe access 736 bool _do_not_unlock_if_synchronized; // Do not unlock the receiver of a synchronized method (since it was 737 // never locked) when throwing an exception. Used by interpreter only. 738 739 // Flag to mark a JNI thread in the process of attaching - See CR 6404306 740 // This flag is never set true other than at construction, and in that case 741 // is shortly thereafter set false 742 volatile bool _is_attaching; 743 744 public: 745 // State of the stack guard pages for this thread. 746 enum StackGuardState { 747 stack_guard_unused, // not needed 748 stack_guard_yellow_disabled,// disabled (temporarily) after stack overflow 749 stack_guard_enabled // enabled 750 }; 751 752 private: 753 754 StackGuardState _stack_guard_state; 755 756 // Compiler exception handling (NOTE: The _exception_oop is *NOT* the same as _pending_exception. It is 757 // used to temp. parsing values into and out of the runtime system during exception handling for compiled 758 // code) 759 volatile oop _exception_oop; // Exception thrown in compiled code 760 volatile address _exception_pc; // PC where exception happened 761 volatile address _exception_handler_pc; // PC for handler of exception 762 volatile int _exception_stack_size; // Size of frame where exception happened 763 764 // support for compilation 765 bool _is_compiling; // is true if a compilation is active inthis thread (one compilation per thread possible) 766 767 // support for JNI critical regions 768 jint _jni_active_critical; // count of entries into JNI critical region 769 770 // For deadlock detection. 771 int _depth_first_number; 772 773 // JVMTI PopFrame support 774 // This is set to popframe_pending to signal that top Java frame should be popped immediately 775 int _popframe_condition; 776 777 #ifndef PRODUCT 778 int _jmp_ring_index; 779 struct { 780 // We use intptr_t instead of address so debugger doesn't try and display strings 781 intptr_t _target; 782 intptr_t _instruction; 783 const char* _file; 784 int _line; 785 } _jmp_ring[ jump_ring_buffer_size ]; 786 #endif /* PRODUCT */ 787 788 #ifndef SERIALGC 789 // Support for G1 barriers 790 791 ObjPtrQueue _satb_mark_queue; // Thread-local log for SATB barrier. 792 // Set of all such queues. 793 static SATBMarkQueueSet _satb_mark_queue_set; 794 795 DirtyCardQueue _dirty_card_queue; // Thread-local log for dirty cards. 796 // Set of all such queues. 797 static DirtyCardQueueSet _dirty_card_queue_set; 798 799 void flush_barrier_queues(); 800 #endif // !SERIALGC 801 802 friend class VMThread; 803 friend class ThreadWaitTransition; 804 friend class VM_Exit; 805 806 void initialize(); // Initialized the instance variables 807 808 public: 809 // Constructor 810 JavaThread(bool is_attaching = false); // for main thread and JNI attached threads 811 JavaThread(ThreadFunction entry_point, size_t stack_size = 0); 812 ~JavaThread(); 813 814 #ifdef ASSERT 815 // verify this JavaThread hasn't be published in the Threads::list yet 816 void verify_not_published(); 817 #endif 818 819 //JNI functiontable getter/setter for JVMTI jni function table interception API. 820 void set_jni_functions(struct JNINativeInterface_* functionTable) { 821 _jni_environment.functions = functionTable; 822 } 823 struct JNINativeInterface_* get_jni_functions() { 824 return (struct JNINativeInterface_ *)_jni_environment.functions; 825 } 826 827 // Executes Shutdown.shutdown() 828 void invoke_shutdown_hooks(); 829 830 // Cleanup on thread exit 831 enum ExitType { 832 normal_exit, 833 jni_detach 834 }; 835 void exit(bool destroy_vm, ExitType exit_type = normal_exit); 836 837 void cleanup_failed_attach_current_thread(); 838 839 // Testers 840 virtual bool is_Java_thread() const { return true; } 841 842 // compilation 843 void set_is_compiling(bool f) { _is_compiling = f; } 844 bool is_compiling() const { return _is_compiling; } 845 846 // Thread chain operations 847 JavaThread* next() const { return _next; } 848 void set_next(JavaThread* p) { _next = p; } 849 850 // Thread oop. threadObj() can be NULL for initial JavaThread 851 // (or for threads attached via JNI) 852 oop threadObj() const { return _threadObj; } 853 void set_threadObj(oop p) { _threadObj = p; } 854 855 ThreadPriority java_priority() const; // Read from threadObj() 856 857 // Prepare thread and add to priority queue. If a priority is 858 // not specified, use the priority of the thread object. Threads_lock 859 // must be held while this function is called. 860 void prepare(jobject jni_thread, ThreadPriority prio=NoPriority); 861 862 void set_saved_exception_pc(address pc) { _saved_exception_pc = pc; } 863 address saved_exception_pc() { return _saved_exception_pc; } 864 865 866 ThreadFunction entry_point() const { return _entry_point; } 867 868 // Allocates a new Java level thread object for this thread. thread_name may be NULL. 869 void allocate_threadObj(Handle thread_group, char* thread_name, bool daemon, TRAPS); 870 871 // Last frame anchor routines 872 873 JavaFrameAnchor* frame_anchor(void) { return &_anchor; } 874 875 // last_Java_sp 876 bool has_last_Java_frame() const { return _anchor.has_last_Java_frame(); } 877 intptr_t* last_Java_sp() const { return _anchor.last_Java_sp(); } 878 879 // last_Java_pc 880 881 address last_Java_pc(void) { return _anchor.last_Java_pc(); } 882 883 // Safepoint support 884 JavaThreadState thread_state() const { return _thread_state; } 885 void set_thread_state(JavaThreadState s) { _thread_state=s; } 886 ThreadSafepointState *safepoint_state() const { return _safepoint_state; } 887 void set_safepoint_state(ThreadSafepointState *state) { _safepoint_state = state; } 888 bool is_at_poll_safepoint() { return _safepoint_state->is_at_poll_safepoint(); } 889 890 // thread has called JavaThread::exit() or is terminated 891 bool is_exiting() { return _terminated == _thread_exiting || is_terminated(); } 892 // thread is terminated (no longer on the threads list); we compare 893 // against the two non-terminated values so that a freed JavaThread 894 // will also be considered terminated. 895 bool is_terminated() { return _terminated != _not_terminated && _terminated != _thread_exiting; } 896 void set_terminated(TerminatedTypes t) { _terminated = t; } 897 // special for Threads::remove() which is static: 898 void set_terminated_value() { _terminated = _thread_terminated; } 899 void block_if_vm_exited(); 900 901 bool doing_unsafe_access() { return _doing_unsafe_access; } 902 void set_doing_unsafe_access(bool val) { _doing_unsafe_access = val; } 903 904 bool do_not_unlock_if_synchronized() { return _do_not_unlock_if_synchronized; } 905 void set_do_not_unlock_if_synchronized(bool val) { _do_not_unlock_if_synchronized = val; } 906 907 908 // Suspend/resume support for JavaThread 909 910 private: 911 void set_ext_suspended() { set_suspend_flag (_ext_suspended); } 912 void clear_ext_suspended() { clear_suspend_flag(_ext_suspended); } 913 914 public: 915 void java_suspend(); 916 void java_resume(); 917 int java_suspend_self(); 918 919 void check_and_wait_while_suspended() { 920 assert(JavaThread::current() == this, "sanity check"); 921 922 bool do_self_suspend; 923 do { 924 // were we externally suspended while we were waiting? 925 do_self_suspend = handle_special_suspend_equivalent_condition(); 926 if (do_self_suspend) { 927 // don't surprise the thread that suspended us by returning 928 java_suspend_self(); 929 set_suspend_equivalent(); 930 } 931 } while (do_self_suspend); 932 } 933 static void check_safepoint_and_suspend_for_native_trans(JavaThread *thread); 934 // Check for async exception in addition to safepoint and suspend request. 935 static void check_special_condition_for_native_trans(JavaThread *thread); 936 937 bool is_ext_suspend_completed(bool called_by_wait, int delay, uint32_t *bits); 938 bool is_ext_suspend_completed_with_lock(uint32_t *bits) { 939 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 940 // Warning: is_ext_suspend_completed() may temporarily drop the 941 // SR_lock to allow the thread to reach a stable thread state if 942 // it is currently in a transient thread state. 943 return is_ext_suspend_completed(false /*!called_by_wait */, 944 SuspendRetryDelay, bits); 945 } 946 947 // We cannot allow wait_for_ext_suspend_completion() to run forever or 948 // we could hang. SuspendRetryCount and SuspendRetryDelay are normally 949 // passed as the count and delay parameters. Experiments with specific 950 // calls to wait_for_ext_suspend_completion() can be done by passing 951 // other values in the code. Experiments with all calls can be done 952 // via the appropriate -XX options. 953 bool wait_for_ext_suspend_completion(int count, int delay, uint32_t *bits); 954 955 void set_external_suspend() { set_suspend_flag (_external_suspend); } 956 void clear_external_suspend() { clear_suspend_flag(_external_suspend); } 957 958 void set_deopt_suspend() { set_suspend_flag (_deopt_suspend); } 959 void clear_deopt_suspend() { clear_suspend_flag(_deopt_suspend); } 960 bool is_deopt_suspend() { return (_suspend_flags & _deopt_suspend) != 0; } 961 962 bool is_external_suspend() const { 963 return (_suspend_flags & _external_suspend) != 0; 964 } 965 // Whenever a thread transitions from native to vm/java it must suspend 966 // if external|deopt suspend is present. 967 bool is_suspend_after_native() const { 968 return (_suspend_flags & (_external_suspend | _deopt_suspend) ) != 0; 969 } 970 971 // external suspend request is completed 972 bool is_ext_suspended() const { 973 return (_suspend_flags & _ext_suspended) != 0; 974 } 975 976 bool is_external_suspend_with_lock() const { 977 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 978 return is_external_suspend(); 979 } 980 981 // Special method to handle a pending external suspend request 982 // when a suspend equivalent condition lifts. 983 bool handle_special_suspend_equivalent_condition() { 984 assert(is_suspend_equivalent(), 985 "should only be called in a suspend equivalence condition"); 986 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 987 bool ret = is_external_suspend(); 988 if (!ret) { 989 // not about to self-suspend so clear suspend equivalence 990 clear_suspend_equivalent(); 991 } 992 // implied else: 993 // We have a pending external suspend request so we leave the 994 // suspend_equivalent flag set until java_suspend_self() sets 995 // the ext_suspended flag and clears the suspend_equivalent 996 // flag. This insures that wait_for_ext_suspend_completion() 997 // will return consistent values. 998 return ret; 999 } 1000 1001 // utility methods to see if we are doing some kind of suspension 1002 bool is_being_ext_suspended() const { 1003 MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag); 1004 return is_ext_suspended() || is_external_suspend(); 1005 } 1006 1007 bool is_suspend_equivalent() const { return _suspend_equivalent; } 1008 1009 void set_suspend_equivalent() { _suspend_equivalent = true; }; 1010 void clear_suspend_equivalent() { _suspend_equivalent = false; }; 1011 1012 // Thread.stop support 1013 void send_thread_stop(oop throwable); 1014 AsyncRequests clear_special_runtime_exit_condition() { 1015 AsyncRequests x = _special_runtime_exit_condition; 1016 _special_runtime_exit_condition = _no_async_condition; 1017 return x; 1018 } 1019 1020 // Are any async conditions present? 1021 bool has_async_condition() { return (_special_runtime_exit_condition != _no_async_condition); } 1022 1023 void check_and_handle_async_exceptions(bool check_unsafe_error = true); 1024 1025 // these next two are also used for self-suspension and async exception support 1026 void handle_special_runtime_exit_condition(bool check_asyncs = true); 1027 1028 // Return true if JavaThread has an asynchronous condition or 1029 // if external suspension is requested. 1030 bool has_special_runtime_exit_condition() { 1031 // We call is_external_suspend() last since external suspend should 1032 // be less common. Because we don't use is_external_suspend_with_lock 1033 // it is possible that we won't see an asynchronous external suspend 1034 // request that has just gotten started, i.e., SR_lock grabbed but 1035 // _external_suspend field change either not made yet or not visible 1036 // yet. However, this is okay because the request is asynchronous and 1037 // we will see the new flag value the next time through. It's also 1038 // possible that the external suspend request is dropped after 1039 // we have checked is_external_suspend(), we will recheck its value 1040 // under SR_lock in java_suspend_self(). 1041 return (_special_runtime_exit_condition != _no_async_condition) || 1042 is_external_suspend() || is_deopt_suspend(); 1043 } 1044 1045 void set_pending_unsafe_access_error() { _special_runtime_exit_condition = _async_unsafe_access_error; } 1046 1047 void set_pending_async_exception(oop e) { 1048 _pending_async_exception = e; 1049 _special_runtime_exit_condition = _async_exception; 1050 set_has_async_exception(); 1051 } 1052 1053 // Fast-locking support 1054 bool is_lock_owned(address adr) const; 1055 1056 // Accessors for vframe array top 1057 // The linked list of vframe arrays are sorted on sp. This means when we 1058 // unpack the head must contain the vframe array to unpack. 1059 void set_vframe_array_head(vframeArray* value) { _vframe_array_head = value; } 1060 vframeArray* vframe_array_head() const { return _vframe_array_head; } 1061 1062 // Side structure for defering update of java frame locals until deopt occurs 1063 GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred_locals() const { return _deferred_locals_updates; } 1064 void set_deferred_locals(GrowableArray<jvmtiDeferredLocalVariableSet *>* vf) { _deferred_locals_updates = vf; } 1065 1066 // These only really exist to make debugging deopt problems simpler 1067 1068 void set_vframe_array_last(vframeArray* value) { _vframe_array_last = value; } 1069 vframeArray* vframe_array_last() const { return _vframe_array_last; } 1070 1071 // The special resourceMark used during deoptimization 1072 1073 void set_deopt_mark(DeoptResourceMark* value) { _deopt_mark = value; } 1074 DeoptResourceMark* deopt_mark(void) { return _deopt_mark; } 1075 1076 intptr_t* must_deopt_id() { return _must_deopt_id; } 1077 void set_must_deopt_id(intptr_t* id) { _must_deopt_id = id; } 1078 void clear_must_deopt_id() { _must_deopt_id = NULL; } 1079 1080 methodOop callee_target() const { return _callee_target; } 1081 void set_callee_target (methodOop x) { _callee_target = x; } 1082 1083 // Oop results of vm runtime calls 1084 oop vm_result() const { return _vm_result; } 1085 void set_vm_result (oop x) { _vm_result = x; } 1086 1087 oop vm_result_2() const { return _vm_result_2; } 1088 void set_vm_result_2 (oop x) { _vm_result_2 = x; } 1089 1090 MemRegion deferred_card_mark() const { return _deferred_card_mark; } 1091 void set_deferred_card_mark(MemRegion mr) { _deferred_card_mark = mr; } 1092 1093 // Exception handling for compiled methods 1094 oop exception_oop() const { return _exception_oop; } 1095 int exception_stack_size() const { return _exception_stack_size; } 1096 address exception_pc() const { return _exception_pc; } 1097 address exception_handler_pc() const { return _exception_handler_pc; } 1098 1099 void set_exception_oop(oop o) { _exception_oop = o; } 1100 void set_exception_pc(address a) { _exception_pc = a; } 1101 void set_exception_handler_pc(address a) { _exception_handler_pc = a; } 1102 void set_exception_stack_size(int size) { _exception_stack_size = size; } 1103 1104 // Stack overflow support 1105 inline size_t stack_available(address cur_sp); 1106 address stack_yellow_zone_base() 1107 { return (address)(stack_base() - (stack_size() - (stack_red_zone_size() + stack_yellow_zone_size()))); } 1108 size_t stack_yellow_zone_size() 1109 { return StackYellowPages * os::vm_page_size(); } 1110 address stack_red_zone_base() 1111 { return (address)(stack_base() - (stack_size() - stack_red_zone_size())); } 1112 size_t stack_red_zone_size() 1113 { return StackRedPages * os::vm_page_size(); } 1114 bool in_stack_yellow_zone(address a) 1115 { return (a <= stack_yellow_zone_base()) && (a >= stack_red_zone_base()); } 1116 bool in_stack_red_zone(address a) 1117 { return (a <= stack_red_zone_base()) && (a >= (address)((intptr_t)stack_base() - stack_size())); } 1118 1119 void create_stack_guard_pages(); 1120 void remove_stack_guard_pages(); 1121 1122 void enable_stack_yellow_zone(); 1123 void disable_stack_yellow_zone(); 1124 void enable_stack_red_zone(); 1125 void disable_stack_red_zone(); 1126 1127 inline bool stack_yellow_zone_disabled(); 1128 inline bool stack_yellow_zone_enabled(); 1129 1130 // Attempt to reguard the stack after a stack overflow may have occurred. 1131 // Returns true if (a) guard pages are not needed on this thread, (b) the 1132 // pages are already guarded, or (c) the pages were successfully reguarded. 1133 // Returns false if there is not enough stack space to reguard the pages, in 1134 // which case the caller should unwind a frame and try again. The argument 1135 // should be the caller's (approximate) sp. 1136 bool reguard_stack(address cur_sp); 1137 // Similar to above but see if current stackpoint is out of the guard area 1138 // and reguard if possible. 1139 bool reguard_stack(void); 1140 1141 // Misc. accessors/mutators 1142 void set_do_not_unlock(void) { _do_not_unlock_if_synchronized = true; } 1143 void clr_do_not_unlock(void) { _do_not_unlock_if_synchronized = false; } 1144 bool do_not_unlock(void) { return _do_not_unlock_if_synchronized; } 1145 1146 #ifndef PRODUCT 1147 void record_jump(address target, address instr, const char* file, int line); 1148 #endif /* PRODUCT */ 1149 1150 // For assembly stub generation 1151 static ByteSize threadObj_offset() { return byte_offset_of(JavaThread, _threadObj ); } 1152 #ifndef PRODUCT 1153 static ByteSize jmp_ring_index_offset() { return byte_offset_of(JavaThread, _jmp_ring_index ); } 1154 static ByteSize jmp_ring_offset() { return byte_offset_of(JavaThread, _jmp_ring ); } 1155 #endif /* PRODUCT */ 1156 static ByteSize jni_environment_offset() { return byte_offset_of(JavaThread, _jni_environment ); } 1157 static ByteSize last_Java_sp_offset() { 1158 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_sp_offset(); 1159 } 1160 static ByteSize last_Java_pc_offset() { 1161 return byte_offset_of(JavaThread, _anchor) + JavaFrameAnchor::last_Java_pc_offset(); 1162 } 1163 static ByteSize frame_anchor_offset() { 1164 return byte_offset_of(JavaThread, _anchor); 1165 } 1166 static ByteSize callee_target_offset() { return byte_offset_of(JavaThread, _callee_target ); } 1167 static ByteSize vm_result_offset() { return byte_offset_of(JavaThread, _vm_result ); } 1168 static ByteSize vm_result_2_offset() { return byte_offset_of(JavaThread, _vm_result_2 ); } 1169 static ByteSize thread_state_offset() { return byte_offset_of(JavaThread, _thread_state ); } 1170 static ByteSize saved_exception_pc_offset() { return byte_offset_of(JavaThread, _saved_exception_pc ); } 1171 static ByteSize osthread_offset() { return byte_offset_of(JavaThread, _osthread ); } 1172 static ByteSize exception_oop_offset() { return byte_offset_of(JavaThread, _exception_oop ); } 1173 static ByteSize exception_pc_offset() { return byte_offset_of(JavaThread, _exception_pc ); } 1174 static ByteSize exception_handler_pc_offset() { return byte_offset_of(JavaThread, _exception_handler_pc); } 1175 static ByteSize exception_stack_size_offset() { return byte_offset_of(JavaThread, _exception_stack_size); } 1176 static ByteSize stack_guard_state_offset() { return byte_offset_of(JavaThread, _stack_guard_state ); } 1177 static ByteSize suspend_flags_offset() { return byte_offset_of(JavaThread, _suspend_flags ); } 1178 1179 static ByteSize do_not_unlock_if_synchronized_offset() { return byte_offset_of(JavaThread, _do_not_unlock_if_synchronized); } 1180 1181 #ifndef SERIALGC 1182 static ByteSize satb_mark_queue_offset() { return byte_offset_of(JavaThread, _satb_mark_queue); } 1183 static ByteSize dirty_card_queue_offset() { return byte_offset_of(JavaThread, _dirty_card_queue); } 1184 #endif // !SERIALGC 1185 1186 // Returns the jni environment for this thread 1187 JNIEnv* jni_environment() { return &_jni_environment; } 1188 1189 static JavaThread* thread_from_jni_environment(JNIEnv* env) { 1190 JavaThread *thread_from_jni_env = (JavaThread*)((intptr_t)env - in_bytes(jni_environment_offset())); 1191 // Only return NULL if thread is off the thread list; starting to 1192 // exit should not return NULL. 1193 if (thread_from_jni_env->is_terminated()) { 1194 thread_from_jni_env->block_if_vm_exited(); 1195 return NULL; 1196 } else { 1197 return thread_from_jni_env; 1198 } 1199 } 1200 1201 // JNI critical regions. These can nest. 1202 bool in_critical() { return _jni_active_critical > 0; } 1203 void enter_critical() { assert(Thread::current() == this, 1204 "this must be current thread"); 1205 _jni_active_critical++; } 1206 void exit_critical() { assert(Thread::current() == this, 1207 "this must be current thread"); 1208 _jni_active_critical--; 1209 assert(_jni_active_critical >= 0, 1210 "JNI critical nesting problem?"); } 1211 1212 // For deadlock detection 1213 int depth_first_number() { return _depth_first_number; } 1214 void set_depth_first_number(int dfn) { _depth_first_number = dfn; } 1215 1216 private: 1217 void set_monitor_chunks(MonitorChunk* monitor_chunks) { _monitor_chunks = monitor_chunks; } 1218 1219 public: 1220 MonitorChunk* monitor_chunks() const { return _monitor_chunks; } 1221 void add_monitor_chunk(MonitorChunk* chunk); 1222 void remove_monitor_chunk(MonitorChunk* chunk); 1223 bool in_deopt_handler() const { return _in_deopt_handler > 0; } 1224 void inc_in_deopt_handler() { _in_deopt_handler++; } 1225 void dec_in_deopt_handler() { 1226 assert(_in_deopt_handler > 0, "mismatched deopt nesting"); 1227 if (_in_deopt_handler > 0) { // robustness 1228 _in_deopt_handler--; 1229 } 1230 } 1231 1232 private: 1233 void set_entry_point(ThreadFunction entry_point) { _entry_point = entry_point; } 1234 1235 public: 1236 1237 // Frame iteration; calls the function f for all frames on the stack 1238 void frames_do(void f(frame*, const RegisterMap*)); 1239 1240 // Memory operations 1241 void oops_do(OopClosure* f, CodeBlobClosure* cf); 1242 1243 // Sweeper operations 1244 void nmethods_do(CodeBlobClosure* cf); 1245 1246 // Memory management operations 1247 void gc_epilogue(); 1248 void gc_prologue(); 1249 1250 // Misc. operations 1251 char* name() const { return (char*)get_thread_name(); } 1252 void print_on(outputStream* st) const; 1253 void print() const { print_on(tty); } 1254 void print_value(); 1255 void print_thread_state_on(outputStream* ) const PRODUCT_RETURN; 1256 void print_thread_state() const PRODUCT_RETURN; 1257 void print_on_error(outputStream* st, char* buf, int buflen) const; 1258 void verify(); 1259 const char* get_thread_name() const; 1260 private: 1261 // factor out low-level mechanics for use in both normal and error cases 1262 const char* get_thread_name_string(char* buf = NULL, int buflen = 0) const; 1263 public: 1264 const char* get_threadgroup_name() const; 1265 const char* get_parent_name() const; 1266 1267 // Accessing frames 1268 frame last_frame() { 1269 _anchor.make_walkable(this); 1270 return pd_last_frame(); 1271 } 1272 javaVFrame* last_java_vframe(RegisterMap* reg_map); 1273 1274 // Returns method at 'depth' java or native frames down the stack 1275 // Used for security checks 1276 klassOop security_get_caller_class(int depth); 1277 1278 // Print stack trace in external format 1279 void print_stack_on(outputStream* st); 1280 void print_stack() { print_stack_on(tty); } 1281 1282 // Print stack traces in various internal formats 1283 void trace_stack() PRODUCT_RETURN; 1284 void trace_stack_from(vframe* start_vf) PRODUCT_RETURN; 1285 void trace_frames() PRODUCT_RETURN; 1286 1287 // Returns the number of stack frames on the stack 1288 int depth() const; 1289 1290 // Function for testing deoptimization 1291 void deoptimize(); 1292 void make_zombies(); 1293 1294 void deoptimized_wrt_marked_nmethods(); 1295 1296 // Profiling operation (see fprofile.cpp) 1297 public: 1298 bool profile_last_Java_frame(frame* fr); 1299 1300 private: 1301 ThreadProfiler* _thread_profiler; 1302 private: 1303 friend class FlatProfiler; // uses both [gs]et_thread_profiler. 1304 friend class FlatProfilerTask; // uses get_thread_profiler. 1305 friend class ThreadProfilerMark; // uses get_thread_profiler. 1306 ThreadProfiler* get_thread_profiler() { return _thread_profiler; } 1307 ThreadProfiler* set_thread_profiler(ThreadProfiler* tp) { 1308 ThreadProfiler* result = _thread_profiler; 1309 _thread_profiler = tp; 1310 return result; 1311 } 1312 1313 // Static operations 1314 public: 1315 // Returns the running thread as a JavaThread 1316 static inline JavaThread* current(); 1317 1318 // Returns the active Java thread. Do not use this if you know you are calling 1319 // from a JavaThread, as it's slower than JavaThread::current. If called from 1320 // the VMThread, it also returns the JavaThread that instigated the VMThread's 1321 // operation. You may not want that either. 1322 static JavaThread* active(); 1323 1324 inline CompilerThread* as_CompilerThread(); 1325 1326 public: 1327 virtual void run(); 1328 void thread_main_inner(); 1329 1330 private: 1331 // PRIVILEGED STACK 1332 PrivilegedElement* _privileged_stack_top; 1333 GrowableArray<oop>* _array_for_gc; 1334 public: 1335 1336 // Returns the privileged_stack information. 1337 PrivilegedElement* privileged_stack_top() const { return _privileged_stack_top; } 1338 void set_privileged_stack_top(PrivilegedElement *e) { _privileged_stack_top = e; } 1339 void register_array_for_gc(GrowableArray<oop>* array) { _array_for_gc = array; } 1340 1341 public: 1342 // Thread local information maintained by JVMTI. 1343 void set_jvmti_thread_state(JvmtiThreadState *value) { _jvmti_thread_state = value; } 1344 // A JvmtiThreadState is lazily allocated. This jvmti_thread_state() 1345 // getter is used to get this JavaThread's JvmtiThreadState if it has 1346 // one which means NULL can be returned. JvmtiThreadState::state_for() 1347 // is used to get the specified JavaThread's JvmtiThreadState if it has 1348 // one or it allocates a new JvmtiThreadState for the JavaThread and 1349 // returns it. JvmtiThreadState::state_for() will return NULL only if 1350 // the specified JavaThread is exiting. 1351 JvmtiThreadState *jvmti_thread_state() const { return _jvmti_thread_state; } 1352 static ByteSize jvmti_thread_state_offset() { return byte_offset_of(JavaThread, _jvmti_thread_state); } 1353 void set_jvmti_get_loaded_classes_closure(JvmtiGetLoadedClassesClosure* value) { _jvmti_get_loaded_classes_closure = value; } 1354 JvmtiGetLoadedClassesClosure* get_jvmti_get_loaded_classes_closure() const { return _jvmti_get_loaded_classes_closure; } 1355 1356 // JVMTI PopFrame support 1357 // Setting and clearing popframe_condition 1358 // All of these enumerated values are bits. popframe_pending 1359 // indicates that a PopFrame() has been requested and not yet been 1360 // completed. popframe_processing indicates that that PopFrame() is in 1361 // the process of being completed. popframe_force_deopt_reexecution_bit 1362 // indicates that special handling is required when returning to a 1363 // deoptimized caller. 1364 enum PopCondition { 1365 popframe_inactive = 0x00, 1366 popframe_pending_bit = 0x01, 1367 popframe_processing_bit = 0x02, 1368 popframe_force_deopt_reexecution_bit = 0x04 1369 }; 1370 PopCondition popframe_condition() { return (PopCondition) _popframe_condition; } 1371 void set_popframe_condition(PopCondition c) { _popframe_condition = c; } 1372 void set_popframe_condition_bit(PopCondition c) { _popframe_condition |= c; } 1373 void clear_popframe_condition() { _popframe_condition = popframe_inactive; } 1374 static ByteSize popframe_condition_offset() { return byte_offset_of(JavaThread, _popframe_condition); } 1375 bool has_pending_popframe() { return (popframe_condition() & popframe_pending_bit) != 0; } 1376 bool popframe_forcing_deopt_reexecution() { return (popframe_condition() & popframe_force_deopt_reexecution_bit) != 0; } 1377 void clear_popframe_forcing_deopt_reexecution() { _popframe_condition &= ~popframe_force_deopt_reexecution_bit; } 1378 #ifdef CC_INTERP 1379 bool pop_frame_pending(void) { return ((_popframe_condition & popframe_pending_bit) != 0); } 1380 void clr_pop_frame_pending(void) { _popframe_condition = popframe_inactive; } 1381 bool pop_frame_in_process(void) { return ((_popframe_condition & popframe_processing_bit) != 0); } 1382 void set_pop_frame_in_process(void) { _popframe_condition |= popframe_processing_bit; } 1383 void clr_pop_frame_in_process(void) { _popframe_condition &= ~popframe_processing_bit; } 1384 #endif 1385 1386 private: 1387 // Saved incoming arguments to popped frame. 1388 // Used only when popped interpreted frame returns to deoptimized frame. 1389 void* _popframe_preserved_args; 1390 int _popframe_preserved_args_size; 1391 1392 public: 1393 void popframe_preserve_args(ByteSize size_in_bytes, void* start); 1394 void* popframe_preserved_args(); 1395 ByteSize popframe_preserved_args_size(); 1396 WordSize popframe_preserved_args_size_in_words(); 1397 void popframe_free_preserved_args(); 1398 1399 1400 private: 1401 JvmtiThreadState *_jvmti_thread_state; 1402 JvmtiGetLoadedClassesClosure* _jvmti_get_loaded_classes_closure; 1403 1404 // Used by the interpreter in fullspeed mode for frame pop, method 1405 // entry, method exit and single stepping support. This field is 1406 // only set to non-zero by the VM_EnterInterpOnlyMode VM operation. 1407 // It can be set to zero asynchronously (i.e., without a VM operation 1408 // or a lock) so we have to be very careful. 1409 int _interp_only_mode; 1410 1411 public: 1412 // used by the interpreter for fullspeed debugging support (see above) 1413 static ByteSize interp_only_mode_offset() { return byte_offset_of(JavaThread, _interp_only_mode); } 1414 bool is_interp_only_mode() { return (_interp_only_mode != 0); } 1415 int get_interp_only_mode() { return _interp_only_mode; } 1416 void increment_interp_only_mode() { ++_interp_only_mode; } 1417 void decrement_interp_only_mode() { --_interp_only_mode; } 1418 1419 private: 1420 ThreadStatistics *_thread_stat; 1421 1422 public: 1423 ThreadStatistics* get_thread_stat() const { return _thread_stat; } 1424 1425 // Return a blocker object for which this thread is blocked parking. 1426 oop current_park_blocker(); 1427 1428 private: 1429 static size_t _stack_size_at_create; 1430 1431 public: 1432 static inline size_t stack_size_at_create(void) { 1433 return _stack_size_at_create; 1434 } 1435 static inline void set_stack_size_at_create(size_t value) { 1436 _stack_size_at_create = value; 1437 } 1438 1439 #ifndef SERIALGC 1440 // SATB marking queue support 1441 ObjPtrQueue& satb_mark_queue() { return _satb_mark_queue; } 1442 static SATBMarkQueueSet& satb_mark_queue_set() { 1443 return _satb_mark_queue_set; 1444 } 1445 1446 // Dirty card queue support 1447 DirtyCardQueue& dirty_card_queue() { return _dirty_card_queue; } 1448 static DirtyCardQueueSet& dirty_card_queue_set() { 1449 return _dirty_card_queue_set; 1450 } 1451 #endif // !SERIALGC 1452 1453 // Machine dependent stuff 1454 #include "incls/_thread_pd.hpp.incl" 1455 1456 public: 1457 void set_blocked_on_compilation(bool value) { 1458 _blocked_on_compilation = value; 1459 } 1460 1461 bool blocked_on_compilation() { 1462 return _blocked_on_compilation; 1463 } 1464 protected: 1465 bool _blocked_on_compilation; 1466 1467 1468 // JSR166 per-thread parker 1469 private: 1470 Parker* _parker; 1471 public: 1472 Parker* parker() { return _parker; } 1473 1474 // Biased locking support 1475 private: 1476 GrowableArray<MonitorInfo*>* _cached_monitor_info; 1477 public: 1478 GrowableArray<MonitorInfo*>* cached_monitor_info() { return _cached_monitor_info; } 1479 void set_cached_monitor_info(GrowableArray<MonitorInfo*>* info) { _cached_monitor_info = info; } 1480 1481 // clearing/querying jni attach status 1482 bool is_attaching() const { return _is_attaching; } 1483 void set_attached() { _is_attaching = false; OrderAccess::fence(); } 1484 private: 1485 // This field is used to determine if a thread has claimed 1486 // a par_id: it is -1 if the thread has not claimed a par_id; 1487 // otherwise its value is the par_id that has been claimed. 1488 int _claimed_par_id; 1489 public: 1490 int get_claimed_par_id() { return _claimed_par_id; } 1491 void set_claimed_par_id(int id) { _claimed_par_id = id;} 1492 }; 1493 1494 // Inline implementation of JavaThread::current 1495 inline JavaThread* JavaThread::current() { 1496 Thread* thread = ThreadLocalStorage::thread(); 1497 assert(thread != NULL && thread->is_Java_thread(), "just checking"); 1498 return (JavaThread*)thread; 1499 } 1500 1501 inline CompilerThread* JavaThread::as_CompilerThread() { 1502 assert(is_Compiler_thread(), "just checking"); 1503 return (CompilerThread*)this; 1504 } 1505 1506 inline bool JavaThread::stack_yellow_zone_disabled() { 1507 return _stack_guard_state == stack_guard_yellow_disabled; 1508 } 1509 1510 inline bool JavaThread::stack_yellow_zone_enabled() { 1511 #ifdef ASSERT 1512 if (os::uses_stack_guard_pages()) { 1513 assert(_stack_guard_state != stack_guard_unused, "guard pages must be in use"); 1514 } 1515 #endif 1516 return _stack_guard_state == stack_guard_enabled; 1517 } 1518 1519 inline size_t JavaThread::stack_available(address cur_sp) { 1520 // This code assumes java stacks grow down 1521 address low_addr; // Limit on the address for deepest stack depth 1522 if ( _stack_guard_state == stack_guard_unused) { 1523 low_addr = stack_base() - stack_size(); 1524 } else { 1525 low_addr = stack_yellow_zone_base(); 1526 } 1527 return cur_sp > low_addr ? cur_sp - low_addr : 0; 1528 } 1529 1530 // A JavaThread for low memory detection support 1531 class LowMemoryDetectorThread : public JavaThread { 1532 friend class VMStructs; 1533 public: 1534 LowMemoryDetectorThread(ThreadFunction entry_point) : JavaThread(entry_point) {}; 1535 1536 // Hide this thread from external view. 1537 bool is_hidden_from_external_view() const { return true; } 1538 }; 1539 1540 // A thread used for Compilation. 1541 class CompilerThread : public JavaThread { 1542 friend class VMStructs; 1543 private: 1544 CompilerCounters* _counters; 1545 1546 ciEnv* _env; 1547 CompileLog* _log; 1548 CompileTask* _task; 1549 CompileQueue* _queue; 1550 1551 public: 1552 1553 static CompilerThread* current(); 1554 1555 CompilerThread(CompileQueue* queue, CompilerCounters* counters); 1556 1557 bool is_Compiler_thread() const { return true; } 1558 // Hide this compiler thread from external view. 1559 bool is_hidden_from_external_view() const { return true; } 1560 1561 CompileQueue* queue() { return _queue; } 1562 CompilerCounters* counters() { return _counters; } 1563 1564 // Get/set the thread's compilation environment. 1565 ciEnv* env() { return _env; } 1566 void set_env(ciEnv* env) { _env = env; } 1567 1568 // Get/set the thread's logging information 1569 CompileLog* log() { return _log; } 1570 void init_log(CompileLog* log) { 1571 // Set once, for good. 1572 assert(_log == NULL, "set only once"); 1573 _log = log; 1574 } 1575 1576 #ifndef PRODUCT 1577 private: 1578 IdealGraphPrinter *_ideal_graph_printer; 1579 public: 1580 IdealGraphPrinter *ideal_graph_printer() { return _ideal_graph_printer; } 1581 void set_ideal_graph_printer(IdealGraphPrinter *n) { _ideal_graph_printer = n; } 1582 #endif 1583 1584 // Get/set the thread's current task 1585 CompileTask* task() { return _task; } 1586 void set_task(CompileTask* task) { _task = task; } 1587 }; 1588 1589 inline CompilerThread* CompilerThread::current() { 1590 return JavaThread::current()->as_CompilerThread(); 1591 } 1592 1593 1594 // The active thread queue. It also keeps track of the current used 1595 // thread priorities. 1596 class Threads: AllStatic { 1597 friend class VMStructs; 1598 private: 1599 static JavaThread* _thread_list; 1600 static int _number_of_threads; 1601 static int _number_of_non_daemon_threads; 1602 static int _return_code; 1603 1604 public: 1605 // Thread management 1606 // force_daemon is a concession to JNI, where we may need to add a 1607 // thread to the thread list before allocating its thread object 1608 static void add(JavaThread* p, bool force_daemon = false); 1609 static void remove(JavaThread* p); 1610 static bool includes(JavaThread* p); 1611 static JavaThread* first() { return _thread_list; } 1612 static void threads_do(ThreadClosure* tc); 1613 1614 // Initializes the vm and creates the vm thread 1615 static jint create_vm(JavaVMInitArgs* args, bool* canTryAgain); 1616 static void convert_vm_init_libraries_to_agents(); 1617 static void create_vm_init_libraries(); 1618 static void create_vm_init_agents(); 1619 static void shutdown_vm_agents(); 1620 static bool destroy_vm(); 1621 // Supported VM versions via JNI 1622 // Includes JNI_VERSION_1_1 1623 static jboolean is_supported_jni_version_including_1_1(jint version); 1624 // Does not include JNI_VERSION_1_1 1625 static jboolean is_supported_jni_version(jint version); 1626 1627 // Garbage collection 1628 static void follow_other_roots(void f(oop*)); 1629 1630 // Apply "f->do_oop" to all root oops in all threads. 1631 // This version may only be called by sequential code. 1632 static void oops_do(OopClosure* f, CodeBlobClosure* cf); 1633 // This version may be called by sequential or parallel code. 1634 static void possibly_parallel_oops_do(OopClosure* f, CodeBlobClosure* cf); 1635 // This creates a list of GCTasks, one per thread. 1636 static void create_thread_roots_tasks(GCTaskQueue* q); 1637 // This creates a list of GCTasks, one per thread, for marking objects. 1638 static void create_thread_roots_marking_tasks(GCTaskQueue* q); 1639 1640 // Apply "f->do_oop" to roots in all threads that 1641 // are part of compiled frames 1642 static void compiled_frame_oops_do(OopClosure* f, CodeBlobClosure* cf); 1643 1644 static void convert_hcode_pointers(); 1645 static void restore_hcode_pointers(); 1646 1647 // Sweeper 1648 static void nmethods_do(CodeBlobClosure* cf); 1649 1650 static void gc_epilogue(); 1651 static void gc_prologue(); 1652 1653 // Verification 1654 static void verify(); 1655 static void print_on(outputStream* st, bool print_stacks, bool internal_format, bool print_concurrent_locks); 1656 static void print(bool print_stacks, bool internal_format) { 1657 // this function is only used by debug.cpp 1658 print_on(tty, print_stacks, internal_format, false /* no concurrent lock printed */); 1659 } 1660 static void print_on_error(outputStream* st, Thread* current, char* buf, int buflen); 1661 1662 // Get Java threads that are waiting to enter a monitor. If doLock 1663 // is true, then Threads_lock is grabbed as needed. Otherwise, the 1664 // VM needs to be at a safepoint. 1665 static GrowableArray<JavaThread*>* get_pending_threads(int count, 1666 address monitor, bool doLock); 1667 1668 // Get owning Java thread from the monitor's owner field. If doLock 1669 // is true, then Threads_lock is grabbed as needed. Otherwise, the 1670 // VM needs to be at a safepoint. 1671 static JavaThread *owning_thread_from_monitor_owner(address owner, 1672 bool doLock); 1673 1674 // Number of threads on the active threads list 1675 static int number_of_threads() { return _number_of_threads; } 1676 // Number of non-daemon threads on the active threads list 1677 static int number_of_non_daemon_threads() { return _number_of_non_daemon_threads; } 1678 1679 // Deoptimizes all frames tied to marked nmethods 1680 static void deoptimized_wrt_marked_nmethods(); 1681 1682 }; 1683 1684 1685 // Thread iterator 1686 class ThreadClosure: public StackObj { 1687 public: 1688 virtual void do_thread(Thread* thread) = 0; 1689 }; 1690 1691 class SignalHandlerMark: public StackObj { 1692 private: 1693 Thread* _thread; 1694 public: 1695 SignalHandlerMark(Thread* t) { 1696 _thread = t; 1697 if (_thread) _thread->enter_signal_handler(); 1698 } 1699 ~SignalHandlerMark() { 1700 if (_thread) _thread->leave_signal_handler(); 1701 _thread = NULL; 1702 } 1703 }; 1704 1705 // ParkEvents are type-stable and immortal. 1706 // 1707 // Lifecycle: Once a ParkEvent is associated with a thread that ParkEvent remains 1708 // associated with the thread for the thread's entire lifetime - the relationship is 1709 // stable. A thread will be associated at most one ParkEvent. When the thread 1710 // expires, the ParkEvent moves to the EventFreeList. New threads attempt to allocate from 1711 // the EventFreeList before creating a new Event. Type-stability frees us from 1712 // worrying about stale Event or Thread references in the objectMonitor subsystem. 1713 // (A reference to ParkEvent is always valid, even though the event may no longer be associated 1714 // with the desired or expected thread. A key aspect of this design is that the callers of 1715 // park, unpark, etc must tolerate stale references and spurious wakeups). 1716 // 1717 // Only the "associated" thread can block (park) on the ParkEvent, although 1718 // any other thread can unpark a reachable parkevent. Park() is allowed to 1719 // return spuriously. In fact park-unpark a really just an optimization to 1720 // avoid unbounded spinning and surrender the CPU to be a polite system citizen. 1721 // A degenerate albeit "impolite" park-unpark implementation could simply return. 1722 // See http://blogs.sun.com/dave for more details. 1723 // 1724 // Eventually I'd like to eliminate Events and ObjectWaiters, both of which serve as 1725 // thread proxies, and simply make the THREAD structure type-stable and persistent. 1726 // Currently, we unpark events associated with threads, but ideally we'd just 1727 // unpark threads. 1728 // 1729 // The base-class, PlatformEvent, is platform-specific while the ParkEvent is 1730 // platform-independent. PlatformEvent provides park(), unpark(), etc., and 1731 // is abstract -- that is, a PlatformEvent should never be instantiated except 1732 // as part of a ParkEvent. 1733 // Equivalently we could have defined a platform-independent base-class that 1734 // exported Allocate(), Release(), etc. The platform-specific class would extend 1735 // that base-class, adding park(), unpark(), etc. 1736 // 1737 // A word of caution: The JVM uses 2 very similar constructs: 1738 // 1. ParkEvent are used for Java-level "monitor" synchronization. 1739 // 2. Parkers are used by JSR166-JUC park-unpark. 1740 // 1741 // We'll want to eventually merge these redundant facilities and use ParkEvent. 1742 1743 1744 class ParkEvent : public os::PlatformEvent { 1745 private: 1746 ParkEvent * FreeNext ; 1747 1748 // Current association 1749 Thread * AssociatedWith ; 1750 intptr_t RawThreadIdentity ; // LWPID etc 1751 volatile int Incarnation ; 1752 1753 // diagnostic : keep track of last thread to wake this thread. 1754 // this is useful for construction of dependency graphs. 1755 void * LastWaker ; 1756 1757 public: 1758 // MCS-CLH list linkage and Native Mutex/Monitor 1759 ParkEvent * volatile ListNext ; 1760 ParkEvent * volatile ListPrev ; 1761 volatile intptr_t OnList ; 1762 volatile int TState ; 1763 volatile int Notified ; // for native monitor construct 1764 volatile int IsWaiting ; // Enqueued on WaitSet 1765 1766 1767 private: 1768 static ParkEvent * volatile FreeList ; 1769 static volatile int ListLock ; 1770 1771 // It's prudent to mark the dtor as "private" 1772 // ensuring that it's not visible outside the package. 1773 // Unfortunately gcc warns about such usage, so 1774 // we revert to the less desirable "protected" visibility. 1775 // The other compilers accept private dtors. 1776 1777 protected: // Ensure dtor is never invoked 1778 ~ParkEvent() { guarantee (0, "invariant") ; } 1779 1780 ParkEvent() : PlatformEvent() { 1781 AssociatedWith = NULL ; 1782 FreeNext = NULL ; 1783 ListNext = NULL ; 1784 ListPrev = NULL ; 1785 OnList = 0 ; 1786 TState = 0 ; 1787 Notified = 0 ; 1788 IsWaiting = 0 ; 1789 } 1790 1791 // We use placement-new to force ParkEvent instances to be 1792 // aligned on 256-byte address boundaries. This ensures that the least 1793 // significant byte of a ParkEvent address is always 0. 1794 1795 void * operator new (size_t sz) ; 1796 void operator delete (void * a) ; 1797 1798 public: 1799 static ParkEvent * Allocate (Thread * t) ; 1800 static void Release (ParkEvent * e) ; 1801 } ;