jdk-sandbox: comparison src/hotspot/share/runtime/thread.cpp

equal deleted inserted replaced

-:4ebc2e2fb97c
+:71c04702a3d5
+/*
+* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+* or visit www.oracle.com if you need additional information or have any
+* questions.
+*
+*/
+#include "precompiled.hpp"
+#include "classfile/classLoader.hpp"
+#include "classfile/javaClasses.hpp"
+#include "classfile/moduleEntry.hpp"
+#include "classfile/systemDictionary.hpp"
+#include "classfile/vmSymbols.hpp"
+#include "code/codeCache.hpp"
+#include "code/scopeDesc.hpp"
+#include "compiler/compileBroker.hpp"
+#include "compiler/compileTask.hpp"
+#include "gc/shared/gcId.hpp"
+#include "gc/shared/gcLocker.inline.hpp"
+#include "gc/shared/workgroup.hpp"
+#include "interpreter/interpreter.hpp"
+#include "interpreter/linkResolver.hpp"
+#include "interpreter/oopMapCache.hpp"
+#include "jvmtifiles/jvmtiEnv.hpp"
+#include "logging/log.hpp"
+#include "logging/logConfiguration.hpp"
+#include "logging/logStream.hpp"
+#include "memory/metaspaceShared.hpp"
+#include "memory/oopFactory.hpp"
+#include "memory/resourceArea.hpp"
+#include "memory/universe.inline.hpp"
+#include "oops/instanceKlass.hpp"
+#include "oops/objArrayOop.hpp"
+#include "oops/oop.inline.hpp"
+#include "oops/symbol.hpp"
+#include "oops/verifyOopClosure.hpp"
+#include "prims/jvm.h"
+#include "prims/jvm_misc.hpp"
+#include "prims/jvmtiExport.hpp"
+#include "prims/jvmtiThreadState.hpp"
+#include "prims/privilegedStack.hpp"
+#include "runtime/arguments.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/biasedLocking.hpp"
+#include "runtime/commandLineFlagConstraintList.hpp"
+#include "runtime/commandLineFlagWriteableList.hpp"
+#include "runtime/commandLineFlagRangeList.hpp"
+#include "runtime/deoptimization.hpp"
+#include "runtime/frame.inline.hpp"
+#include "runtime/globals.hpp"
+#include "runtime/init.hpp"
+#include "runtime/interfaceSupport.hpp"
+#include "runtime/java.hpp"
+#include "runtime/javaCalls.hpp"
+#include "runtime/jniPeriodicChecker.hpp"
+#include "runtime/timerTrace.hpp"
+#include "runtime/memprofiler.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/objectMonitor.hpp"
+#include "runtime/orderAccess.inline.hpp"
+#include "runtime/osThread.hpp"
+#include "runtime/safepoint.hpp"
+#include "runtime/sharedRuntime.hpp"
+#include "runtime/statSampler.hpp"
+#include "runtime/stubRoutines.hpp"
+#include "runtime/sweeper.hpp"
+#include "runtime/task.hpp"
+#include "runtime/thread.inline.hpp"
+#include "runtime/threadCritical.hpp"
+#include "runtime/vframe.hpp"
+#include "runtime/vframeArray.hpp"
+#include "runtime/vframe_hp.hpp"
+#include "runtime/vmThread.hpp"
+#include "runtime/vm_operations.hpp"
+#include "runtime/vm_version.hpp"
+#include "services/attachListener.hpp"
+#include "services/management.hpp"
+#include "services/memTracker.hpp"
+#include "services/threadService.hpp"
+#include "trace/traceMacros.hpp"
+#include "trace/tracing.hpp"
+#include "utilities/align.hpp"
+#include "utilities/defaultStream.hpp"
+#include "utilities/dtrace.hpp"
+#include "utilities/events.hpp"
+#include "utilities/macros.hpp"
+#include "utilities/preserveException.hpp"
+#include "utilities/vmError.hpp"
+#if INCLUDE_ALL_GCS
+#include "gc/cms/concurrentMarkSweepThread.hpp"
+#include "gc/g1/concurrentMarkThread.inline.hpp"
+#include "gc/parallel/pcTasks.hpp"
+#endif // INCLUDE_ALL_GCS
+#if INCLUDE_JVMCI
+#include "jvmci/jvmciCompiler.hpp"
+#include "jvmci/jvmciRuntime.hpp"
+#include "logging/logHandle.hpp"
+#endif
+#ifdef COMPILER1
+#include "c1/c1_Compiler.hpp"
+#endif
+#ifdef COMPILER2
+#include "opto/c2compiler.hpp"
+#include "opto/idealGraphPrinter.hpp"
+#endif
+#if INCLUDE_RTM_OPT
+#include "runtime/rtmLocking.hpp"
+#endif
+// Initialization after module runtime initialization
+void universe_post_module_init();  // must happen after call_initPhase2
+#ifdef DTRACE_ENABLED
+// Only bother with this argument setup if dtrace is available
+#define HOTSPOT_THREAD_PROBE_start HOTSPOT_THREAD_START
+#define HOTSPOT_THREAD_PROBE_stop HOTSPOT_THREAD_STOP
+#define DTRACE_THREAD_PROBE(probe, javathread)                           \
+{                                                                      \
+ResourceMark rm(this);                                               \
+int len = 0;                                                         \
+const char* name = (javathread)->get_thread_name();                  \
+len = strlen(name);                                                  \
+HOTSPOT_THREAD_PROBE_##probe(/* probe = start, stop */               \
+(char *) name, len,                                                \
+java_lang_Thread::thread_id((javathread)->threadObj()),            \
+(uintptr_t) (javathread)->osthread()->thread_id(),                 \
+java_lang_Thread::is_daemon((javathread)->threadObj()));           \
+}
+#else //  ndef DTRACE_ENABLED
+#define DTRACE_THREAD_PROBE(probe, javathread)
+#endif // ndef DTRACE_ENABLED
+#ifndef USE_LIBRARY_BASED_TLS_ONLY
+// Current thread is maintained as a thread-local variable
+THREAD_LOCAL_DECL Thread* Thread::_thr_current = NULL;
+#endif
+// Class hierarchy
+// - Thread
+//   - VMThread
+//   - WatcherThread
+//   - ConcurrentMarkSweepThread
+//   - JavaThread
+//     - CompilerThread
+// ======= Thread ========
+// Support for forcing alignment of thread objects for biased locking
+void* Thread::allocate(size_t size, bool throw_excpt, MEMFLAGS flags) {
+if (UseBiasedLocking) {
+const int alignment = markOopDesc::biased_lock_alignment;
+size_t aligned_size = size + (alignment - sizeof(intptr_t));
+void* real_malloc_addr = throw_excpt? AllocateHeap(aligned_size, flags, CURRENT_PC)
+: AllocateHeap(aligned_size, flags, CURRENT_PC,
+AllocFailStrategy::RETURN_NULL);
+void* aligned_addr     = align_up(real_malloc_addr, alignment);
+assert(((uintptr_t) aligned_addr + (uintptr_t) size) <=
+((uintptr_t) real_malloc_addr + (uintptr_t) aligned_size),
+"JavaThread alignment code overflowed allocated storage");
+if (aligned_addr != real_malloc_addr) {
+log_info(biasedlocking)("Aligned thread " INTPTR_FORMAT " to " INTPTR_FORMAT,
+p2i(real_malloc_addr),
+p2i(aligned_addr));
+}
+((Thread*) aligned_addr)->_real_malloc_address = real_malloc_addr;
+return aligned_addr;
+} else {
+return throw_excpt? AllocateHeap(size, flags, CURRENT_PC)
+: AllocateHeap(size, flags, CURRENT_PC, AllocFailStrategy::RETURN_NULL);
+}
+}
+void Thread::operator delete(void* p) {
+if (UseBiasedLocking) {
+void* real_malloc_addr = ((Thread*) p)->_real_malloc_address;
+FreeHeap(real_malloc_addr);
+} else {
+FreeHeap(p);
+}
+}
+// Base class for all threads: VMThread, WatcherThread, ConcurrentMarkSweepThread,
+// JavaThread
+Thread::Thread() {
+// stack and get_thread
+set_stack_base(NULL);
+set_stack_size(0);
+set_self_raw_id(0);
+set_lgrp_id(-1);
+DEBUG_ONLY(clear_suspendible_thread();)
+// allocated data structures
+set_osthread(NULL);
+set_resource_area(new (mtThread)ResourceArea());
+DEBUG_ONLY(_current_resource_mark = NULL;)
+set_handle_area(new (mtThread) HandleArea(NULL));
+set_metadata_handles(new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(30, true));
+set_active_handles(NULL);
+set_free_handle_block(NULL);
+set_last_handle_mark(NULL);
+// This initial value ==> never claimed.
+_oops_do_parity = 0;
+// the handle mark links itself to last_handle_mark
+new HandleMark(this);
+// plain initialization
+debug_only(_owned_locks = NULL;)
+debug_only(_allow_allocation_count = 0;)
+NOT_PRODUCT(_allow_safepoint_count = 0;)
+NOT_PRODUCT(_skip_gcalot = false;)
+_jvmti_env_iteration_count = 0;
+set_allocated_bytes(0);
+_vm_operation_started_count = 0;
+_vm_operation_completed_count = 0;
+_current_pending_monitor = NULL;
+_current_pending_monitor_is_from_java = true;
+_current_waiting_monitor = NULL;
+_num_nested_signal = 0;
+omFreeList = NULL;
+omFreeCount = 0;
+omFreeProvision = 32;
+omInUseList = NULL;
+omInUseCount = 0;
+#ifdef ASSERT
+_visited_for_critical_count = false;
+#endif
+_SR_lock = new Monitor(Mutex::suspend_resume, "SR_lock", true,
+Monitor::_safepoint_check_sometimes);
+_suspend_flags = 0;
+// thread-specific hashCode stream generator state - Marsaglia shift-xor form
+_hashStateX = os::random();
+_hashStateY = 842502087;
+_hashStateZ = 0x8767;    // (int)(3579807591LL & 0xffff) ;
+_hashStateW = 273326509;
+_OnTrap   = 0;
+_schedctl = NULL;
+_Stalled  = 0;
+_TypeTag  = 0x2BAD;
+// Many of the following fields are effectively final - immutable
+// Note that nascent threads can't use the Native Monitor-Mutex
+// construct until the _MutexEvent is initialized ...
+// CONSIDER: instead of using a fixed set of purpose-dedicated ParkEvents
+// we might instead use a stack of ParkEvents that we could provision on-demand.
+// The stack would act as a cache to avoid calls to ParkEvent::Allocate()
+// and ::Release()
+_ParkEvent   = ParkEvent::Allocate(this);
+_SleepEvent  = ParkEvent::Allocate(this);
+_MutexEvent  = ParkEvent::Allocate(this);
+_MuxEvent    = ParkEvent::Allocate(this);
+#ifdef CHECK_UNHANDLED_OOPS
+if (CheckUnhandledOops) {
+_unhandled_oops = new UnhandledOops(this);
+}
+#endif // CHECK_UNHANDLED_OOPS
+#ifdef ASSERT
+if (UseBiasedLocking) {
+assert((((uintptr_t) this) & (markOopDesc::biased_lock_alignment - 1)) == 0, "forced alignment of thread object failed");
+assert(this == _real_malloc_address ||
+this == align_up(_real_malloc_address, (int)markOopDesc::biased_lock_alignment),
+"bug in forced alignment of thread objects");
+}
+#endif // ASSERT
+}
+void Thread::initialize_thread_current() {
+#ifndef USE_LIBRARY_BASED_TLS_ONLY
+assert(_thr_current == NULL, "Thread::current already initialized");
+_thr_current = this;
+#endif
+assert(ThreadLocalStorage::thread() == NULL, "ThreadLocalStorage::thread already initialized");
+ThreadLocalStorage::set_thread(this);
+assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
+}
+void Thread::clear_thread_current() {
+assert(Thread::current() == ThreadLocalStorage::thread(), "TLS mismatch!");
+#ifndef USE_LIBRARY_BASED_TLS_ONLY
+_thr_current = NULL;
+#endif
+ThreadLocalStorage::set_thread(NULL);
+}
+void Thread::record_stack_base_and_size() {
+set_stack_base(os::current_stack_base());
+set_stack_size(os::current_stack_size());
+// CR 7190089: on Solaris, primordial thread's stack is adjusted
+// in initialize_thread(). Without the adjustment, stack size is
+// incorrect if stack is set to unlimited (ulimit -s unlimited).
+// So far, only Solaris has real implementation of initialize_thread().
+//
+// set up any platform-specific state.
+os::initialize_thread(this);
+// Set stack limits after thread is initialized.
+if (is_Java_thread()) {
+((JavaThread*) this)->set_stack_overflow_limit();
+((JavaThread*) this)->set_reserved_stack_activation(stack_base());
+}
+#if INCLUDE_NMT
+// record thread's native stack, stack grows downward
+MemTracker::record_thread_stack(stack_end(), stack_size());
+#endif // INCLUDE_NMT
+log_debug(os, thread)("Thread " UINTX_FORMAT " stack dimensions: "
+PTR_FORMAT "-" PTR_FORMAT " (" SIZE_FORMAT "k).",
+os::current_thread_id(), p2i(stack_base() - stack_size()),
+p2i(stack_base()), stack_size()/1024);
+}
+Thread::~Thread() {
+EVENT_THREAD_DESTRUCT(this);
+// stack_base can be NULL if the thread is never started or exited before
+// record_stack_base_and_size called. Although, we would like to ensure
+// that all started threads do call record_stack_base_and_size(), there is
+// not proper way to enforce that.
+#if INCLUDE_NMT
+if (_stack_base != NULL) {
+MemTracker::release_thread_stack(stack_end(), stack_size());
+#ifdef ASSERT
+set_stack_base(NULL);
+#endif
+}
+#endif // INCLUDE_NMT
+// deallocate data structures
+delete resource_area();
+// since the handle marks are using the handle area, we have to deallocated the root
+// handle mark before deallocating the thread's handle area,
+assert(last_handle_mark() != NULL, "check we have an element");
+delete last_handle_mark();
+assert(last_handle_mark() == NULL, "check we have reached the end");
+// It's possible we can encounter a null _ParkEvent, etc., in stillborn threads.
+// We NULL out the fields for good hygiene.
+ParkEvent::Release(_ParkEvent); _ParkEvent   = NULL;
+ParkEvent::Release(_SleepEvent); _SleepEvent  = NULL;
+ParkEvent::Release(_MutexEvent); _MutexEvent  = NULL;
+ParkEvent::Release(_MuxEvent); _MuxEvent    = NULL;
+delete handle_area();
+delete metadata_handles();
+// SR_handler uses this as a termination indicator -
+// needs to happen before os::free_thread()
+delete _SR_lock;
+_SR_lock = NULL;
+// osthread() can be NULL, if creation of thread failed.
+if (osthread() != NULL) os::free_thread(osthread());
+// clear Thread::current if thread is deleting itself.
+// Needed to ensure JNI correctly detects non-attached threads.
+if (this == Thread::current()) {
+clear_thread_current();
+}
+CHECK_UNHANDLED_OOPS_ONLY(if (CheckUnhandledOops) delete unhandled_oops();)
+}
+// NOTE: dummy function for assertion purpose.
+void Thread::run() {
+ShouldNotReachHere();
+}
+#ifdef ASSERT
+// Private method to check for dangling thread pointer
+void check_for_dangling_thread_pointer(Thread *thread) {
+assert(!thread->is_Java_thread() || Thread::current() == thread || Threads_lock->owned_by_self(),
+"possibility of dangling Thread pointer");
+}
+#endif
+ThreadPriority Thread::get_priority(const Thread* const thread) {
+ThreadPriority priority;
+// Can return an error!
+(void)os::get_priority(thread, priority);
+assert(MinPriority <= priority && priority <= MaxPriority, "non-Java priority found");
+return priority;
+}
+void Thread::set_priority(Thread* thread, ThreadPriority priority) {
+debug_only(check_for_dangling_thread_pointer(thread);)
+// Can return an error!
+(void)os::set_priority(thread, priority);
+}
+void Thread::start(Thread* thread) {
+// Start is different from resume in that its safety is guaranteed by context or
+// being called from a Java method synchronized on the Thread object.
+if (!DisableStartThread) {
+if (thread->is_Java_thread()) {
+// Initialize the thread state to RUNNABLE before starting this thread.
+// Can not set it after the thread started because we do not know the
+// exact thread state at that time. It could be in MONITOR_WAIT or
+// in SLEEPING or some other state.
+java_lang_Thread::set_thread_status(((JavaThread*)thread)->threadObj(),
+java_lang_Thread::RUNNABLE);
+}
+os::start_thread(thread);
+}
+}
+// Enqueue a VM_Operation to do the job for us - sometime later
+void Thread::send_async_exception(oop java_thread, oop java_throwable) {
+VM_ThreadStop* vm_stop = new VM_ThreadStop(java_thread, java_throwable);
+VMThread::execute(vm_stop);
+}
+// Check if an external suspend request has completed (or has been
+// cancelled). Returns true if the thread is externally suspended and
+// false otherwise.
+//
+// The bits parameter returns information about the code path through
+// the routine. Useful for debugging:
+//
+// set in is_ext_suspend_completed():
+// 0x00000001 - routine was entered
+// 0x00000010 - routine return false at end
+// 0x00000100 - thread exited (return false)
+// 0x00000200 - suspend request cancelled (return false)
+// 0x00000400 - thread suspended (return true)
+// 0x00001000 - thread is in a suspend equivalent state (return true)
+// 0x00002000 - thread is native and walkable (return true)
+// 0x00004000 - thread is native_trans and walkable (needed retry)
+//
+// set in wait_for_ext_suspend_completion():
+// 0x00010000 - routine was entered
+// 0x00020000 - suspend request cancelled before loop (return false)
+// 0x00040000 - thread suspended before loop (return true)
+// 0x00080000 - suspend request cancelled in loop (return false)
+// 0x00100000 - thread suspended in loop (return true)
+// 0x00200000 - suspend not completed during retry loop (return false)
+// Helper class for tracing suspend wait debug bits.
+//
+// 0x00000100 indicates that the target thread exited before it could
+// self-suspend which is not a wait failure. 0x00000200, 0x00020000 and
+// 0x00080000 each indicate a cancelled suspend request so they don't
+// count as wait failures either.
+#define DEBUG_FALSE_BITS (0x00000010 | 0x00200000)
+class TraceSuspendDebugBits : public StackObj {
+private:
+JavaThread * jt;
+bool         is_wait;
+bool         called_by_wait;  // meaningful when !is_wait
+uint32_t *   bits;
+public:
+TraceSuspendDebugBits(JavaThread *_jt, bool _is_wait, bool _called_by_wait,
+uint32_t *_bits) {
+jt             = _jt;
+is_wait        = _is_wait;
+called_by_wait = _called_by_wait;
+bits           = _bits;
+}
+~TraceSuspendDebugBits() {
+if (!is_wait) {
+#if 1
+// By default, don't trace bits for is_ext_suspend_completed() calls.
+// That trace is very chatty.
+return;
+#else
+if (!called_by_wait) {
+// If tracing for is_ext_suspend_completed() is enabled, then only
+// trace calls to it from wait_for_ext_suspend_completion()
+return;
+}
+#endif
+}
+if (AssertOnSuspendWaitFailure || TraceSuspendWaitFailures) {
+if (bits != NULL && (*bits & DEBUG_FALSE_BITS) != 0) {
+MutexLocker ml(Threads_lock);  // needed for get_thread_name()
+ResourceMark rm;
+tty->print_cr(
+"Failed wait_for_ext_suspend_completion(thread=%s, debug_bits=%x)",
+jt->get_thread_name(), *bits);
+guarantee(!AssertOnSuspendWaitFailure, "external suspend wait failed");
+}
+}
+}
+};
+#undef DEBUG_FALSE_BITS
+bool JavaThread::is_ext_suspend_completed(bool called_by_wait, int delay,
+uint32_t *bits) {
+TraceSuspendDebugBits tsdb(this, false /* !is_wait */, called_by_wait, bits);
+bool did_trans_retry = false;  // only do thread_in_native_trans retry once
+bool do_trans_retry;           // flag to force the retry
+*bits |= 0x00000001;
+do {
+do_trans_retry = false;
+if (is_exiting()) {
+// Thread is in the process of exiting. This is always checked
+// first to reduce the risk of dereferencing a freed JavaThread.
+*bits |= 0x00000100;
+return false;
+}
+if (!is_external_suspend()) {
+// Suspend request is cancelled. This is always checked before
+// is_ext_suspended() to reduce the risk of a rogue resume
+// confusing the thread that made the suspend request.
+*bits |= 0x00000200;
+return false;
+}
+if (is_ext_suspended()) {
+// thread is suspended
+*bits |= 0x00000400;
+return true;
+}
+// Now that we no longer do hard suspends of threads running
+// native code, the target thread can be changing thread state
+// while we are in this routine:
+//
+//   _thread_in_native -> _thread_in_native_trans -> _thread_blocked
+//
+// We save a copy of the thread state as observed at this moment
+// and make our decision about suspend completeness based on the
+// copy. This closes the race where the thread state is seen as
+// _thread_in_native_trans in the if-thread_blocked check, but is
+// seen as _thread_blocked in if-thread_in_native_trans check.
+JavaThreadState save_state = thread_state();
+if (save_state == _thread_blocked && is_suspend_equivalent()) {
+// If the thread's state is _thread_blocked and this blocking
+// condition is known to be equivalent to a suspend, then we can
+// consider the thread to be externally suspended. This means that
+// the code that sets _thread_blocked has been modified to do
+// self-suspension if the blocking condition releases. We also
+// used to check for CONDVAR_WAIT here, but that is now covered by
+// the _thread_blocked with self-suspension check.
+//
+// Return true since we wouldn't be here unless there was still an
+// external suspend request.
+*bits |= 0x00001000;
+return true;
+} else if (save_state == _thread_in_native && frame_anchor()->walkable()) {
+// Threads running native code will self-suspend on native==>VM/Java
+// transitions. If its stack is walkable (should always be the case
+// unless this function is called before the actual java_suspend()
+// call), then the wait is done.
+*bits |= 0x00002000;
+return true;
+} else if (!called_by_wait && !did_trans_retry &&
+save_state == _thread_in_native_trans &&
+frame_anchor()->walkable()) {
+// The thread is transitioning from thread_in_native to another
+// thread state. check_safepoint_and_suspend_for_native_trans()
+// will force the thread to self-suspend. If it hasn't gotten
+// there yet we may have caught the thread in-between the native
+// code check above and the self-suspend. Lucky us. If we were
+// called by wait_for_ext_suspend_completion(), then it
+// will be doing the retries so we don't have to.
+//
+// Since we use the saved thread state in the if-statement above,
+// there is a chance that the thread has already transitioned to
+// _thread_blocked by the time we get here. In that case, we will
+// make a single unnecessary pass through the logic below. This
+// doesn't hurt anything since we still do the trans retry.
+*bits |= 0x00004000;
+// Once the thread leaves thread_in_native_trans for another
+// thread state, we break out of this retry loop. We shouldn't
+// need this flag to prevent us from getting back here, but
+// sometimes paranoia is good.
+did_trans_retry = true;
+// We wait for the thread to transition to a more usable state.
+for (int i = 1; i <= SuspendRetryCount; i++) {
+// We used to do an "os::yield_all(i)" call here with the intention
+// that yielding would increase on each retry. However, the parameter
+// is ignored on Linux which means the yield didn't scale up. Waiting
+// on the SR_lock below provides a much more predictable scale up for
+// the delay. It also provides a simple/direct point to check for any
+// safepoint requests from the VMThread
+// temporarily drops SR_lock while doing wait with safepoint check
+// (if we're a JavaThread - the WatcherThread can also call this)
+// and increase delay with each retry
+SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
+// check the actual thread state instead of what we saved above
+if (thread_state() != _thread_in_native_trans) {
+// the thread has transitioned to another thread state so
+// try all the checks (except this one) one more time.
+do_trans_retry = true;
+break;
+}
+} // end retry loop
+}
+} while (do_trans_retry);
+*bits |= 0x00000010;
+return false;
+}
+// Wait for an external suspend request to complete (or be cancelled).
+// Returns true if the thread is externally suspended and false otherwise.
+//
+bool JavaThread::wait_for_ext_suspend_completion(int retries, int delay,
+uint32_t *bits) {
+TraceSuspendDebugBits tsdb(this, true /* is_wait */,
+false /* !called_by_wait */, bits);
+// local flag copies to minimize SR_lock hold time
+bool is_suspended;
+bool pending;
+uint32_t reset_bits;
+// set a marker so is_ext_suspend_completed() knows we are the caller
+*bits |= 0x00010000;
+// We use reset_bits to reinitialize the bits value at the top of
+// each retry loop. This allows the caller to make use of any
+// unused bits for their own marking purposes.
+reset_bits = *bits;
+{
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
+delay, bits);
+pending = is_external_suspend();
+}
+// must release SR_lock to allow suspension to complete
+if (!pending) {
+// A cancelled suspend request is the only false return from
+// is_ext_suspend_completed() that keeps us from entering the
+// retry loop.
+*bits |= 0x00020000;
+return false;
+}
+if (is_suspended) {
+*bits |= 0x00040000;
+return true;
+}
+for (int i = 1; i <= retries; i++) {
+*bits = reset_bits;  // reinit to only track last retry
+// We used to do an "os::yield_all(i)" call here with the intention
+// that yielding would increase on each retry. However, the parameter
+// is ignored on Linux which means the yield didn't scale up. Waiting
+// on the SR_lock below provides a much more predictable scale up for
+// the delay. It also provides a simple/direct point to check for any
+// safepoint requests from the VMThread
+{
+MutexLocker ml(SR_lock());
+// wait with safepoint check (if we're a JavaThread - the WatcherThread
+// can also call this)  and increase delay with each retry
+SR_lock()->wait(!Thread::current()->is_Java_thread(), i * delay);
+is_suspended = is_ext_suspend_completed(true /* called_by_wait */,
+delay, bits);
+// It is possible for the external suspend request to be cancelled
+// (by a resume) before the actual suspend operation is completed.
+// Refresh our local copy to see if we still need to wait.
+pending = is_external_suspend();
+}
+if (!pending) {
+// A cancelled suspend request is the only false return from
+// is_ext_suspend_completed() that keeps us from staying in the
+// retry loop.
+*bits |= 0x00080000;
+return false;
+}
+if (is_suspended) {
+*bits |= 0x00100000;
+return true;
+}
+} // end retry loop
+// thread did not suspend after all our retries
+*bits |= 0x00200000;
+return false;
+}
+#ifndef PRODUCT
+void JavaThread::record_jump(address target, address instr, const char* file,
+int line) {
+// This should not need to be atomic as the only way for simultaneous
+// updates is via interrupts. Even then this should be rare or non-existent
+// and we don't care that much anyway.
+int index = _jmp_ring_index;
+_jmp_ring_index = (index + 1) & (jump_ring_buffer_size - 1);
+_jmp_ring[index]._target = (intptr_t) target;
+_jmp_ring[index]._instruction = (intptr_t) instr;
+_jmp_ring[index]._file = file;
+_jmp_ring[index]._line = line;
+}
+#endif // PRODUCT
+void Thread::interrupt(Thread* thread) {
+debug_only(check_for_dangling_thread_pointer(thread);)
+os::interrupt(thread);
+}
+bool Thread::is_interrupted(Thread* thread, bool clear_interrupted) {
+debug_only(check_for_dangling_thread_pointer(thread);)
+// Note:  If clear_interrupted==false, this simply fetches and
+// returns the value of the field osthread()->interrupted().
+return os::is_interrupted(thread, clear_interrupted);
+}
+// GC Support
+bool Thread::claim_oops_do_par_case(int strong_roots_parity) {
+jint thread_parity = _oops_do_parity;
+if (thread_parity != strong_roots_parity) {
+jint res = Atomic::cmpxchg(strong_roots_parity, &_oops_do_parity, thread_parity);
+if (res == thread_parity) {
+return true;
+} else {
+guarantee(res == strong_roots_parity, "Or else what?");
+return false;
+}
+}
+return false;
+}
+void Thread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
+active_handles()->oops_do(f);
+// Do oop for ThreadShadow
+f->do_oop((oop*)&_pending_exception);
+handle_area()->oops_do(f);
+if (MonitorInUseLists) {
+// When using thread local monitor lists, we scan them here,
+// and the remaining global monitors in ObjectSynchronizer::oops_do().
+ObjectSynchronizer::thread_local_used_oops_do(this, f);
+}
+}
+void Thread::metadata_handles_do(void f(Metadata*)) {
+// Only walk the Handles in Thread.
+if (metadata_handles() != NULL) {
+for (int i = 0; i< metadata_handles()->length(); i++) {
+f(metadata_handles()->at(i));
+}
+}
+}
+void Thread::print_on(outputStream* st) const {
+// get_priority assumes osthread initialized
+if (osthread() != NULL) {
+int os_prio;
+if (os::get_native_priority(this, &os_prio) == OS_OK) {
+st->print("os_prio=%d ", os_prio);
+}
+st->print("tid=" INTPTR_FORMAT " ", p2i(this));
+ext().print_on(st);
+osthread()->print_on(st);
+}
+debug_only(if (WizardMode) print_owned_locks_on(st);)
+}
+// Thread::print_on_error() is called by fatal error handler. Don't use
+// any lock or allocate memory.
+void Thread::print_on_error(outputStream* st, char* buf, int buflen) const {
+assert(!(is_Compiler_thread() || is_Java_thread()), "Can't call name() here if it allocates");
+if (is_VM_thread())                 { st->print("VMThread"); }
+else if (is_GC_task_thread())       { st->print("GCTaskThread"); }
+else if (is_Watcher_thread())       { st->print("WatcherThread"); }
+else if (is_ConcurrentGC_thread())  { st->print("ConcurrentGCThread"); }
+else                                { st->print("Thread"); }
+if (is_Named_thread()) {
+st->print(" \"%s\"", name());
+}
+st->print(" [stack: " PTR_FORMAT "," PTR_FORMAT "]",
+p2i(stack_end()), p2i(stack_base()));
+if (osthread()) {
+st->print(" [id=%d]", osthread()->thread_id());
+}
+}
+void Thread::print_value_on(outputStream* st) const {
+if (is_Named_thread()) {
+st->print(" \"%s\" ", name());
+}
+st->print(INTPTR_FORMAT, p2i(this));   // print address
+}
+#ifdef ASSERT
+void Thread::print_owned_locks_on(outputStream* st) const {
+Monitor *cur = _owned_locks;
+if (cur == NULL) {
+st->print(" (no locks) ");
+} else {
+st->print_cr(" Locks owned:");
+while (cur) {
+cur->print_on(st);
+cur = cur->next();
+}
+}
+}
+static int ref_use_count  = 0;
+bool Thread::owns_locks_but_compiled_lock() const {
+for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
+if (cur != Compile_lock) return true;
+}
+return false;
+}
+#endif
+#ifndef PRODUCT
+// The flag: potential_vm_operation notifies if this particular safepoint state could potential
+// invoke the vm-thread (i.e., and oop allocation). In that case, we also have to make sure that
+// no threads which allow_vm_block's are held
+void Thread::check_for_valid_safepoint_state(bool potential_vm_operation) {
+// Check if current thread is allowed to block at a safepoint
+if (!(_allow_safepoint_count == 0)) {
+fatal("Possible safepoint reached by thread that does not allow it");
+}
+if (is_Java_thread() && ((JavaThread*)this)->thread_state() != _thread_in_vm) {
+fatal("LEAF method calling lock?");
+}
+#ifdef ASSERT
+if (potential_vm_operation && is_Java_thread()
+&& !Universe::is_bootstrapping()) {
+// Make sure we do not hold any locks that the VM thread also uses.
+// This could potentially lead to deadlocks
+for (Monitor *cur = _owned_locks; cur; cur = cur->next()) {
+// Threads_lock is special, since the safepoint synchronization will not start before this is
+// acquired. Hence, a JavaThread cannot be holding it at a safepoint. So is VMOperationRequest_lock,
+// since it is used to transfer control between JavaThreads and the VMThread
+// Do not *exclude* any locks unless you are absolutely sure it is correct. Ask someone else first!
+if ((cur->allow_vm_block() &&
+cur != Threads_lock &&
+cur != Compile_lock &&               // Temporary: should not be necessary when we get separate compilation
+cur != VMOperationRequest_lock &&
+cur != VMOperationQueue_lock) ||
+cur->rank() == Mutex::special) {
+fatal("Thread holding lock at safepoint that vm can block on: %s", cur->name());
+}
+}
+}
+if (GCALotAtAllSafepoints) {
+// We could enter a safepoint here and thus have a gc
+InterfaceSupport::check_gc_alot();
+}
+#endif
+}
+#endif
+bool Thread::is_in_stack(address adr) const {
+assert(Thread::current() == this, "is_in_stack can only be called from current thread");
+address end = os::current_stack_pointer();
+// Allow non Java threads to call this without stack_base
+if (_stack_base == NULL) return true;
+if (stack_base() >= adr && adr >= end) return true;
+return false;
+}
+bool Thread::is_in_usable_stack(address adr) const {
+size_t stack_guard_size = os::uses_stack_guard_pages() ? JavaThread::stack_guard_zone_size() : 0;
+size_t usable_stack_size = _stack_size - stack_guard_size;
+return ((adr < stack_base()) && (adr >= stack_base() - usable_stack_size));
+}
+// We had to move these methods here, because vm threads get into ObjectSynchronizer::enter
+// However, there is a note in JavaThread::is_lock_owned() about the VM threads not being
+// used for compilation in the future. If that change is made, the need for these methods
+// should be revisited, and they should be removed if possible.
+bool Thread::is_lock_owned(address adr) const {
+return on_local_stack(adr);
+}
+bool Thread::set_as_starting_thread() {
+// NOTE: this must be called inside the main thread.
+return os::create_main_thread((JavaThread*)this);
+}
+static void initialize_class(Symbol* class_name, TRAPS) {
+Klass* klass = SystemDictionary::resolve_or_fail(class_name, true, CHECK);
+InstanceKlass::cast(klass)->initialize(CHECK);
+}
+// Creates the initial ThreadGroup
+static Handle create_initial_thread_group(TRAPS) {
+Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_ThreadGroup(), true, CHECK_NH);
+InstanceKlass* ik = InstanceKlass::cast(k);
+Handle system_instance = ik->allocate_instance_handle(CHECK_NH);
+{
+JavaValue result(T_VOID);
+JavaCalls::call_special(&result,
+system_instance,
+ik,
+vmSymbols::object_initializer_name(),
+vmSymbols::void_method_signature(),
+CHECK_NH);
+}
+Universe::set_system_thread_group(system_instance());
+Handle main_instance = ik->allocate_instance_handle(CHECK_NH);
+{
+JavaValue result(T_VOID);
+Handle string = java_lang_String::create_from_str("main", CHECK_NH);
+JavaCalls::call_special(&result,
+main_instance,
+ik,
+vmSymbols::object_initializer_name(),
+vmSymbols::threadgroup_string_void_signature(),
+system_instance,
+string,
+CHECK_NH);
+}
+return main_instance;
+}
+// Creates the initial Thread
+static oop create_initial_thread(Handle thread_group, JavaThread* thread,
+TRAPS) {
+Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK_NULL);
+InstanceKlass* ik = InstanceKlass::cast(k);
+instanceHandle thread_oop = ik->allocate_instance_handle(CHECK_NULL);
+java_lang_Thread::set_thread(thread_oop(), thread);
+java_lang_Thread::set_priority(thread_oop(), NormPriority);
+thread->set_threadObj(thread_oop());
+Handle string = java_lang_String::create_from_str("main", CHECK_NULL);
+JavaValue result(T_VOID);
+JavaCalls::call_special(&result, thread_oop,
+ik,
+vmSymbols::object_initializer_name(),
+vmSymbols::threadgroup_string_void_signature(),
+thread_group,
+string,
+CHECK_NULL);
+return thread_oop();
+}
+char java_runtime_name[128] = "";
+char java_runtime_version[128] = "";
+// extract the JRE name from java.lang.VersionProps.java_runtime_name
+static const char* get_java_runtime_name(TRAPS) {
+Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
+Handle(), Handle(), CHECK_AND_CLEAR_NULL);
+fieldDescriptor fd;
+bool found = k != NULL &&
+InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_name_name(),
+vmSymbols::string_signature(), &fd);
+if (found) {
+oop name_oop = k->java_mirror()->obj_field(fd.offset());
+if (name_oop == NULL) {
+return NULL;
+}
+const char* name = java_lang_String::as_utf8_string(name_oop,
+java_runtime_name,
+sizeof(java_runtime_name));
+return name;
+} else {
+return NULL;
+}
+}
+// extract the JRE version from java.lang.VersionProps.java_runtime_version
+static const char* get_java_runtime_version(TRAPS) {
+Klass* k = SystemDictionary::find(vmSymbols::java_lang_VersionProps(),
+Handle(), Handle(), CHECK_AND_CLEAR_NULL);
+fieldDescriptor fd;
+bool found = k != NULL &&
+InstanceKlass::cast(k)->find_local_field(vmSymbols::java_runtime_version_name(),
+vmSymbols::string_signature(), &fd);
+if (found) {
+oop name_oop = k->java_mirror()->obj_field(fd.offset());
+if (name_oop == NULL) {
+return NULL;
+}
+const char* name = java_lang_String::as_utf8_string(name_oop,
+java_runtime_version,
+sizeof(java_runtime_version));
+return name;
+} else {
+return NULL;
+}
+}
+// General purpose hook into Java code, run once when the VM is initialized.
+// The Java library method itself may be changed independently from the VM.
+static void call_postVMInitHook(TRAPS) {
+Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_vm_PostVMInitHook(), THREAD);
+if (klass != NULL) {
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result, klass, vmSymbols::run_method_name(),
+vmSymbols::void_method_signature(),
+CHECK);
+}
+}
+static void reset_vm_info_property(TRAPS) {
+// the vm info string
+ResourceMark rm(THREAD);
+const char *vm_info = VM_Version::vm_info_string();
+// java.lang.System class
+Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
+// setProperty arguments
+Handle key_str    = java_lang_String::create_from_str("java.vm.info", CHECK);
+Handle value_str  = java_lang_String::create_from_str(vm_info, CHECK);
+// return value
+JavaValue r(T_OBJECT);
+// public static String setProperty(String key, String value);
+JavaCalls::call_static(&r,
+klass,
+vmSymbols::setProperty_name(),
+vmSymbols::string_string_string_signature(),
+key_str,
+value_str,
+CHECK);
+}
+void JavaThread::allocate_threadObj(Handle thread_group, const char* thread_name,
+bool daemon, TRAPS) {
+assert(thread_group.not_null(), "thread group should be specified");
+assert(threadObj() == NULL, "should only create Java thread object once");
+Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
+InstanceKlass* ik = InstanceKlass::cast(k);
+instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
+java_lang_Thread::set_thread(thread_oop(), this);
+java_lang_Thread::set_priority(thread_oop(), NormPriority);
+set_threadObj(thread_oop());
+JavaValue result(T_VOID);
+if (thread_name != NULL) {
+Handle name = java_lang_String::create_from_str(thread_name, CHECK);
+// Thread gets assigned specified name and null target
+JavaCalls::call_special(&result,
+thread_oop,
+ik,
+vmSymbols::object_initializer_name(),
+vmSymbols::threadgroup_string_void_signature(),
+thread_group, // Argument 1
+name,         // Argument 2
+THREAD);
+} else {
+// Thread gets assigned name "Thread-nnn" and null target
+// (java.lang.Thread doesn't have a constructor taking only a ThreadGroup argument)
+JavaCalls::call_special(&result,
+thread_oop,
+ik,
+vmSymbols::object_initializer_name(),
+vmSymbols::threadgroup_runnable_void_signature(),
+thread_group, // Argument 1
+Handle(),     // Argument 2
+THREAD);
+}
+if (daemon) {
+java_lang_Thread::set_daemon(thread_oop());
+}
+if (HAS_PENDING_EXCEPTION) {
+return;
+}
+Klass* group =  SystemDictionary::ThreadGroup_klass();
+Handle threadObj(THREAD, this->threadObj());
+JavaCalls::call_special(&result,
+thread_group,
+group,
+vmSymbols::add_method_name(),
+vmSymbols::thread_void_signature(),
+threadObj,          // Arg 1
+THREAD);
+}
+// NamedThread --  non-JavaThread subclasses with multiple
+// uniquely named instances should derive from this.
+NamedThread::NamedThread() : Thread() {
+_name = NULL;
+_processed_thread = NULL;
+_gc_id = GCId::undefined();
+}
+NamedThread::~NamedThread() {
+if (_name != NULL) {
+FREE_C_HEAP_ARRAY(char, _name);
+_name = NULL;
+}
+}
+void NamedThread::set_name(const char* format, ...) {
+guarantee(_name == NULL, "Only get to set name once.");
+_name = NEW_C_HEAP_ARRAY(char, max_name_len, mtThread);
+guarantee(_name != NULL, "alloc failure");
+va_list ap;
+va_start(ap, format);
+jio_vsnprintf(_name, max_name_len, format, ap);
+va_end(ap);
+}
+void NamedThread::initialize_named_thread() {
+set_native_thread_name(name());
+}
+void NamedThread::print_on(outputStream* st) const {
+st->print("\"%s\" ", name());
+Thread::print_on(st);
+st->cr();
+}
+// ======= WatcherThread ========
+// The watcher thread exists to simulate timer interrupts.  It should
+// be replaced by an abstraction over whatever native support for
+// timer interrupts exists on the platform.
+WatcherThread* WatcherThread::_watcher_thread   = NULL;
+bool WatcherThread::_startable = false;
+volatile bool  WatcherThread::_should_terminate = false;
+WatcherThread::WatcherThread() : Thread() {
+assert(watcher_thread() == NULL, "we can only allocate one WatcherThread");
+if (os::create_thread(this, os::watcher_thread)) {
+_watcher_thread = this;
+// Set the watcher thread to the highest OS priority which should not be
+// used, unless a Java thread with priority java.lang.Thread.MAX_PRIORITY
+// is created. The only normal thread using this priority is the reference
+// handler thread, which runs for very short intervals only.
+// If the VMThread's priority is not lower than the WatcherThread profiling
+// will be inaccurate.
+os::set_priority(this, MaxPriority);
+if (!DisableStartThread) {
+os::start_thread(this);
+}
+}
+}
+int WatcherThread::sleep() const {
+// The WatcherThread does not participate in the safepoint protocol
+// for the PeriodicTask_lock because it is not a JavaThread.
+MutexLockerEx ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
+if (_should_terminate) {
+// check for termination before we do any housekeeping or wait
+return 0;  // we did not sleep.
+}
+// remaining will be zero if there are no tasks,
+// causing the WatcherThread to sleep until a task is
+// enrolled
+int remaining = PeriodicTask::time_to_wait();
+int time_slept = 0;
+// we expect this to timeout - we only ever get unparked when
+// we should terminate or when a new task has been enrolled
+OSThreadWaitState osts(this->osthread(), false /* not Object.wait() */);
+jlong time_before_loop = os::javaTimeNanos();
+while (true) {
+bool timedout = PeriodicTask_lock->wait(Mutex::_no_safepoint_check_flag,
+remaining);
+jlong now = os::javaTimeNanos();
+if (remaining == 0) {
+// if we didn't have any tasks we could have waited for a long time
+// consider the time_slept zero and reset time_before_loop
+time_slept = 0;
+time_before_loop = now;
+} else {
+// need to recalculate since we might have new tasks in _tasks
+time_slept = (int) ((now - time_before_loop) / 1000000);
+}
+// Change to task list or spurious wakeup of some kind
+if (timedout || _should_terminate) {
+break;
+}
+remaining = PeriodicTask::time_to_wait();
+if (remaining == 0) {
+// Last task was just disenrolled so loop around and wait until
+// another task gets enrolled
+continue;
+}
+remaining -= time_slept;
+if (remaining <= 0) {
+break;
+}
+}
+return time_slept;
+}
+void WatcherThread::run() {
+assert(this == watcher_thread(), "just checking");
+this->record_stack_base_and_size();
+this->set_native_thread_name(this->name());
+this->set_active_handles(JNIHandleBlock::allocate_block());
+while (true) {
+assert(watcher_thread() == Thread::current(), "thread consistency check");
+assert(watcher_thread() == this, "thread consistency check");
+// Calculate how long it'll be until the next PeriodicTask work
+// should be done, and sleep that amount of time.
+int time_waited = sleep();
+if (VMError::is_error_reported()) {
+// A fatal error has happened, the error handler(VMError::report_and_die)
+// should abort JVM after creating an error log file. However in some
+// rare cases, the error handler itself might deadlock. Here periodically
+// check for error reporting timeouts, and if it happens, just proceed to
+// abort the VM.
+// This code is in WatcherThread because WatcherThread wakes up
+// periodically so the fatal error handler doesn't need to do anything;
+// also because the WatcherThread is less likely to crash than other
+// threads.
+for (;;) {
+// Note: we use naked sleep in this loop because we want to avoid using
+// any kind of VM infrastructure which may be broken at this point.
+if (VMError::check_timeout()) {
+// We hit error reporting timeout. Error reporting was interrupted and
+// will be wrapping things up now (closing files etc). Give it some more
+// time, then quit the VM.
+os::naked_short_sleep(200);
+// Print a message to stderr.
+fdStream err(defaultStream::output_fd());
+err.print_raw_cr("# [ timer expired, abort... ]");
+// skip atexit/vm_exit/vm_abort hooks
+os::die();
+}
+// Wait a second, then recheck for timeout.
+os::naked_short_sleep(999);
+}
+}
+if (_should_terminate) {
+// check for termination before posting the next tick
+break;
+}
+PeriodicTask::real_time_tick(time_waited);
+}
+// Signal that it is terminated
+{
+MutexLockerEx mu(Terminator_lock, Mutex::_no_safepoint_check_flag);
+_watcher_thread = NULL;
+Terminator_lock->notify();
+}
+}
+void WatcherThread::start() {
+assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
+if (watcher_thread() == NULL && _startable) {
+_should_terminate = false;
+// Create the single instance of WatcherThread
+new WatcherThread();
+}
+}
+void WatcherThread::make_startable() {
+assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
+_startable = true;
+}
+void WatcherThread::stop() {
+{
+// Follow normal safepoint aware lock enter protocol since the
+// WatcherThread is stopped by another JavaThread.
+MutexLocker ml(PeriodicTask_lock);
+_should_terminate = true;
+WatcherThread* watcher = watcher_thread();
+if (watcher != NULL) {
+// unpark the WatcherThread so it can see that it should terminate
+watcher->unpark();
+}
+}
+MutexLocker mu(Terminator_lock);
+while (watcher_thread() != NULL) {
+// This wait should make safepoint checks, wait without a timeout,
+// and wait as a suspend-equivalent condition.
+Terminator_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
+Mutex::_as_suspend_equivalent_flag);
+}
+}
+void WatcherThread::unpark() {
+assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");
+PeriodicTask_lock->notify();
+}
+void WatcherThread::print_on(outputStream* st) const {
+st->print("\"%s\" ", name());
+Thread::print_on(st);
+st->cr();
+}
+// ======= JavaThread ========
+#if INCLUDE_JVMCI
+jlong* JavaThread::_jvmci_old_thread_counters;
+bool jvmci_counters_include(JavaThread* thread) {
+oop threadObj = thread->threadObj();
+return !JVMCICountersExcludeCompiler || !thread->is_Compiler_thread();
+}
+void JavaThread::collect_counters(typeArrayOop array) {
+if (JVMCICounterSize > 0) {
+MutexLocker tl(Threads_lock);
+for (int i = 0; i < array->length(); i++) {
+array->long_at_put(i, _jvmci_old_thread_counters[i]);
+}
+for (JavaThread* tp = Threads::first(); tp != NULL; tp = tp->next()) {
+if (jvmci_counters_include(tp)) {
+for (int i = 0; i < array->length(); i++) {
+array->long_at_put(i, array->long_at(i) + tp->_jvmci_counters[i]);
+}
+}
+}
+}
+}
+#endif // INCLUDE_JVMCI
+// A JavaThread is a normal Java thread
+void JavaThread::initialize() {
+// Initialize fields
+set_saved_exception_pc(NULL);
+set_threadObj(NULL);
+_anchor.clear();
+set_entry_point(NULL);
+set_jni_functions(jni_functions());
+set_callee_target(NULL);
+set_vm_result(NULL);
+set_vm_result_2(NULL);
+set_vframe_array_head(NULL);
+set_vframe_array_last(NULL);
+set_deferred_locals(NULL);
+set_deopt_mark(NULL);
+set_deopt_compiled_method(NULL);
+clear_must_deopt_id();
+set_monitor_chunks(NULL);
+set_next(NULL);
+set_thread_state(_thread_new);
+_terminated = _not_terminated;
+_privileged_stack_top = NULL;
+_array_for_gc = NULL;
+_suspend_equivalent = false;
+_in_deopt_handler = 0;
+_doing_unsafe_access = false;
+_stack_guard_state = stack_guard_unused;
+#if INCLUDE_JVMCI
+_pending_monitorenter = false;
+_pending_deoptimization = -1;
+_pending_failed_speculation = NULL;
+_pending_transfer_to_interpreter = false;
+_adjusting_comp_level = false;
+_jvmci._alternate_call_target = NULL;
+assert(_jvmci._implicit_exception_pc == NULL, "must be");
+if (JVMCICounterSize > 0) {
+_jvmci_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
+memset(_jvmci_counters, 0, sizeof(jlong) * JVMCICounterSize);
+} else {
+_jvmci_counters = NULL;
+}
+#endif // INCLUDE_JVMCI
+_reserved_stack_activation = NULL;  // stack base not known yet
+(void)const_cast<oop&>(_exception_oop = oop(NULL));
+_exception_pc  = 0;
+_exception_handler_pc = 0;
+_is_method_handle_return = 0;
+_jvmti_thread_state= NULL;
+_should_post_on_exceptions_flag = JNI_FALSE;
+_jvmti_get_loaded_classes_closure = NULL;
+_interp_only_mode    = 0;
+_special_runtime_exit_condition = _no_async_condition;
+_pending_async_exception = NULL;
+_thread_stat = NULL;
+_thread_stat = new ThreadStatistics();
+_blocked_on_compilation = false;
+_jni_active_critical = 0;
+_pending_jni_exception_check_fn = NULL;
+_do_not_unlock_if_synchronized = false;
+_cached_monitor_info = NULL;
+_parker = Parker::Allocate(this);
+#ifndef PRODUCT
+_jmp_ring_index = 0;
+for (int ji = 0; ji < jump_ring_buffer_size; ji++) {
+record_jump(NULL, NULL, NULL, 0);
+}
+#endif // PRODUCT
+// Setup safepoint state info for this thread
+ThreadSafepointState::create(this);
+debug_only(_java_call_counter = 0);
+// JVMTI PopFrame support
+_popframe_condition = popframe_inactive;
+_popframe_preserved_args = NULL;
+_popframe_preserved_args_size = 0;
+_frames_to_pop_failed_realloc = 0;
+pd_initialize();
+}
+#if INCLUDE_ALL_GCS
+SATBMarkQueueSet JavaThread::_satb_mark_queue_set;
+DirtyCardQueueSet JavaThread::_dirty_card_queue_set;
+#endif // INCLUDE_ALL_GCS
+JavaThread::JavaThread(bool is_attaching_via_jni) :
+Thread()
+#if INCLUDE_ALL_GCS
+, _satb_mark_queue(&_satb_mark_queue_set),
+_dirty_card_queue(&_dirty_card_queue_set)
+#endif // INCLUDE_ALL_GCS
+{
+initialize();
+if (is_attaching_via_jni) {
+_jni_attach_state = _attaching_via_jni;
+} else {
+_jni_attach_state = _not_attaching_via_jni;
+}
+assert(deferred_card_mark().is_empty(), "Default MemRegion ctor");
+}
+bool JavaThread::reguard_stack(address cur_sp) {
+if (_stack_guard_state != stack_guard_yellow_reserved_disabled
+&& _stack_guard_state != stack_guard_reserved_disabled) {
+return true; // Stack already guarded or guard pages not needed.
+}
+if (register_stack_overflow()) {
+// For those architectures which have separate register and
+// memory stacks, we must check the register stack to see if
+// it has overflowed.
+return false;
+}
+// Java code never executes within the yellow zone: the latter is only
+// there to provoke an exception during stack banging.  If java code
+// is executing there, either StackShadowPages should be larger, or
+// some exception code in c1, c2 or the interpreter isn't unwinding
+// when it should.
+guarantee(cur_sp > stack_reserved_zone_base(),
+"not enough space to reguard - increase StackShadowPages");
+if (_stack_guard_state == stack_guard_yellow_reserved_disabled) {
+enable_stack_yellow_reserved_zone();
+if (reserved_stack_activation() != stack_base()) {
+set_reserved_stack_activation(stack_base());
+}
+} else if (_stack_guard_state == stack_guard_reserved_disabled) {
+set_reserved_stack_activation(stack_base());
+enable_stack_reserved_zone();
+}
+return true;
+}
+bool JavaThread::reguard_stack(void) {
+return reguard_stack(os::current_stack_pointer());
+}
+void JavaThread::block_if_vm_exited() {
+if (_terminated == _vm_exited) {
+// _vm_exited is set at safepoint, and Threads_lock is never released
+// we will block here forever
+Threads_lock->lock_without_safepoint_check();
+ShouldNotReachHere();
+}
+}
+// Remove this ifdef when C1 is ported to the compiler interface.
+static void compiler_thread_entry(JavaThread* thread, TRAPS);
+static void sweeper_thread_entry(JavaThread* thread, TRAPS);
+JavaThread::JavaThread(ThreadFunction entry_point, size_t stack_sz) :
+Thread()
+#if INCLUDE_ALL_GCS
+, _satb_mark_queue(&_satb_mark_queue_set),
+_dirty_card_queue(&_dirty_card_queue_set)
+#endif // INCLUDE_ALL_GCS
+{
+initialize();
+_jni_attach_state = _not_attaching_via_jni;
+set_entry_point(entry_point);
+// Create the native thread itself.
+// %note runtime_23
+os::ThreadType thr_type = os::java_thread;
+thr_type = entry_point == &compiler_thread_entry ? os::compiler_thread :
+os::java_thread;
+os::create_thread(this, thr_type, stack_sz);
+// The _osthread may be NULL here because we ran out of memory (too many threads active).
+// We need to throw and OutOfMemoryError - however we cannot do this here because the caller
+// may hold a lock and all locks must be unlocked before throwing the exception (throwing
+// the exception consists of creating the exception object & initializing it, initialization
+// will leave the VM via a JavaCall and then all locks must be unlocked).
+//
+// The thread is still suspended when we reach here. Thread must be explicit started
+// by creator! Furthermore, the thread must also explicitly be added to the Threads list
+// by calling Threads:add. The reason why this is not done here, is because the thread
+// object must be fully initialized (take a look at JVM_Start)
+}
+JavaThread::~JavaThread() {
+// JSR166 -- return the parker to the free list
+Parker::Release(_parker);
+_parker = NULL;
+// Free any remaining  previous UnrollBlock
+vframeArray* old_array = vframe_array_last();
+if (old_array != NULL) {
+Deoptimization::UnrollBlock* old_info = old_array->unroll_block();
+old_array->set_unroll_block(NULL);
+delete old_info;
+delete old_array;
+}
+GrowableArray<jvmtiDeferredLocalVariableSet*>* deferred = deferred_locals();
+if (deferred != NULL) {
+// This can only happen if thread is destroyed before deoptimization occurs.
+assert(deferred->length() != 0, "empty array!");
+do {
+jvmtiDeferredLocalVariableSet* dlv = deferred->at(0);
+deferred->remove_at(0);
+// individual jvmtiDeferredLocalVariableSet are CHeapObj's
+delete dlv;
+} while (deferred->length() != 0);
+delete deferred;
+}
+// All Java related clean up happens in exit
+ThreadSafepointState::destroy(this);
+if (_thread_stat != NULL) delete _thread_stat;
+#if INCLUDE_JVMCI
+if (JVMCICounterSize > 0) {
+if (jvmci_counters_include(this)) {
+for (int i = 0; i < JVMCICounterSize; i++) {
+_jvmci_old_thread_counters[i] += _jvmci_counters[i];
+}
+}
+FREE_C_HEAP_ARRAY(jlong, _jvmci_counters);
+}
+#endif // INCLUDE_JVMCI
+}
+// The first routine called by a new Java thread
+void JavaThread::run() {
+// initialize thread-local alloc buffer related fields
+this->initialize_tlab();
+// used to test validity of stack trace backs
+this->record_base_of_stack_pointer();
+// Record real stack base and size.
+this->record_stack_base_and_size();
+this->create_stack_guard_pages();
+this->cache_global_variables();
+// Thread is now sufficient initialized to be handled by the safepoint code as being
+// in the VM. Change thread state from _thread_new to _thread_in_vm
+ThreadStateTransition::transition_and_fence(this, _thread_new, _thread_in_vm);
+assert(JavaThread::current() == this, "sanity check");
+assert(!Thread::current()->owns_locks(), "sanity check");
+DTRACE_THREAD_PROBE(start, this);
+// This operation might block. We call that after all safepoint checks for a new thread has
+// been completed.
+this->set_active_handles(JNIHandleBlock::allocate_block());
+if (JvmtiExport::should_post_thread_life()) {
+JvmtiExport::post_thread_start(this);
+}
+EventThreadStart event;
+if (event.should_commit()) {
+event.set_thread(THREAD_TRACE_ID(this));
+event.commit();
+}
+// We call another function to do the rest so we are sure that the stack addresses used
+// from there will be lower than the stack base just computed
+thread_main_inner();
+// Note, thread is no longer valid at this point!
+}
+void JavaThread::thread_main_inner() {
+assert(JavaThread::current() == this, "sanity check");
+assert(this->threadObj() != NULL, "just checking");
+// Execute thread entry point unless this thread has a pending exception
+// or has been stopped before starting.
+// Note: Due to JVM_StopThread we can have pending exceptions already!
+if (!this->has_pending_exception() &&
+!java_lang_Thread::is_stillborn(this->threadObj())) {
+{
+ResourceMark rm(this);
+this->set_native_thread_name(this->get_thread_name());
+}
+HandleMark hm(this);
+this->entry_point()(this, this);
+}
+DTRACE_THREAD_PROBE(stop, this);
+this->exit(false);
+delete this;
+}
+static void ensure_join(JavaThread* thread) {
+// We do not need to grap the Threads_lock, since we are operating on ourself.
+Handle threadObj(thread, thread->threadObj());
+assert(threadObj.not_null(), "java thread object must exist");
+ObjectLocker lock(threadObj, thread);
+// Ignore pending exception (ThreadDeath), since we are exiting anyway
+thread->clear_pending_exception();
+// Thread is exiting. So set thread_status field in  java.lang.Thread class to TERMINATED.
+java_lang_Thread::set_thread_status(threadObj(), java_lang_Thread::TERMINATED);
+// Clear the native thread instance - this makes isAlive return false and allows the join()
+// to complete once we've done the notify_all below
+java_lang_Thread::set_thread(threadObj(), NULL);
+lock.notify_all(thread);
+// Ignore pending exception (ThreadDeath), since we are exiting anyway
+thread->clear_pending_exception();
+}
+// For any new cleanup additions, please check to see if they need to be applied to
+// cleanup_failed_attach_current_thread as well.
+void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
+assert(this == JavaThread::current(), "thread consistency check");
+HandleMark hm(this);
+Handle uncaught_exception(this, this->pending_exception());
+this->clear_pending_exception();
+Handle threadObj(this, this->threadObj());
+assert(threadObj.not_null(), "Java thread object should be created");
+// FIXIT: This code should be moved into else part, when reliable 1.2/1.3 check is in place
+{
+EXCEPTION_MARK;
+CLEAR_PENDING_EXCEPTION;
+}
+if (!destroy_vm) {
+if (uncaught_exception.not_null()) {
+EXCEPTION_MARK;
+// Call method Thread.dispatchUncaughtException().
+Klass* thread_klass = SystemDictionary::Thread_klass();
+JavaValue result(T_VOID);
+JavaCalls::call_virtual(&result,
+threadObj, thread_klass,
+vmSymbols::dispatchUncaughtException_name(),
+vmSymbols::throwable_void_signature(),
+uncaught_exception,
+THREAD);
+if (HAS_PENDING_EXCEPTION) {
+ResourceMark rm(this);
+jio_fprintf(defaultStream::error_stream(),
+"\nException: %s thrown from the UncaughtExceptionHandler"
+" in thread \"%s\"\n",
+pending_exception()->klass()->external_name(),
+get_thread_name());
+CLEAR_PENDING_EXCEPTION;
+}
+}
+// Called before the java thread exit since we want to read info
+// from java_lang_Thread object
+EventThreadEnd event;
+if (event.should_commit()) {
+event.set_thread(THREAD_TRACE_ID(this));
+event.commit();
+}
+// Call after last event on thread
+EVENT_THREAD_EXIT(this);
+// Call Thread.exit(). We try 3 times in case we got another Thread.stop during
+// the execution of the method. If that is not enough, then we don't really care. Thread.stop
+// is deprecated anyhow.
+if (!is_Compiler_thread()) {
+int count = 3;
+while (java_lang_Thread::threadGroup(threadObj()) != NULL && (count-- > 0)) {
+EXCEPTION_MARK;
+JavaValue result(T_VOID);
+Klass* thread_klass = SystemDictionary::Thread_klass();
+JavaCalls::call_virtual(&result,
+threadObj, thread_klass,
+vmSymbols::exit_method_name(),
+vmSymbols::void_method_signature(),
+THREAD);
+CLEAR_PENDING_EXCEPTION;
+}
+}
+// notify JVMTI
+if (JvmtiExport::should_post_thread_life()) {
+JvmtiExport::post_thread_end(this);
+}
+// We have notified the agents that we are exiting, before we go on,
+// we must check for a pending external suspend request and honor it
+// in order to not surprise the thread that made the suspend request.
+while (true) {
+{
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+if (!is_external_suspend()) {
+set_terminated(_thread_exiting);
+ThreadService::current_thread_exiting(this);
+break;
+}
+// Implied else:
+// Things get a little tricky here. We have a pending external
+// suspend request, but we are holding the SR_lock so we
+// can't just self-suspend. So we temporarily drop the lock
+// and then self-suspend.
+}
+ThreadBlockInVM tbivm(this);
+java_suspend_self();
+// We're done with this suspend request, but we have to loop around
+// and check again. Eventually we will get SR_lock without a pending
+// external suspend request and will be able to mark ourselves as
+// exiting.
+}
+// no more external suspends are allowed at this point
+} else {
+// before_exit() has already posted JVMTI THREAD_END events
+}
+// Notify waiters on thread object. This has to be done after exit() is called
+// on the thread (if the thread is the last thread in a daemon ThreadGroup the
+// group should have the destroyed bit set before waiters are notified).
+ensure_join(this);
+assert(!this->has_pending_exception(), "ensure_join should have cleared");
+// 6282335 JNI DetachCurrentThread spec states that all Java monitors
+// held by this thread must be released. The spec does not distinguish
+// between JNI-acquired and regular Java monitors. We can only see
+// regular Java monitors here if monitor enter-exit matching is broken.
+//
+// Optionally release any monitors for regular JavaThread exits. This
+// is provided as a work around for any bugs in monitor enter-exit
+// matching. This can be expensive so it is not enabled by default.
+//
+// ensure_join() ignores IllegalThreadStateExceptions, and so does
+// ObjectSynchronizer::release_monitors_owned_by_thread().
+if (exit_type == jni_detach || ObjectMonitor::Knob_ExitRelease) {
+// Sanity check even though JNI DetachCurrentThread() would have
+// returned JNI_ERR if there was a Java frame. JavaThread exit
+// should be done executing Java code by the time we get here.
+assert(!this->has_last_Java_frame(),
+"should not have a Java frame when detaching or exiting");
+ObjectSynchronizer::release_monitors_owned_by_thread(this);
+assert(!this->has_pending_exception(), "release_monitors should have cleared");
+}
+// These things needs to be done while we are still a Java Thread. Make sure that thread
+// is in a consistent state, in case GC happens
+assert(_privileged_stack_top == NULL, "must be NULL when we get here");
+if (active_handles() != NULL) {
+JNIHandleBlock* block = active_handles();
+set_active_handles(NULL);
+JNIHandleBlock::release_block(block);
+}
+if (free_handle_block() != NULL) {
+JNIHandleBlock* block = free_handle_block();
+set_free_handle_block(NULL);
+JNIHandleBlock::release_block(block);
+}
+// These have to be removed while this is still a valid thread.
+remove_stack_guard_pages();
+if (UseTLAB) {
+tlab().make_parsable(true);  // retire TLAB
+}
+if (JvmtiEnv::environments_might_exist()) {
+JvmtiExport::cleanup_thread(this);
+}
+// We must flush any deferred card marks before removing a thread from
+// the list of active threads.
+Universe::heap()->flush_deferred_store_barrier(this);
+assert(deferred_card_mark().is_empty(), "Should have been flushed");
+#if INCLUDE_ALL_GCS
+// We must flush the G1-related buffers before removing a thread
+// from the list of active threads. We must do this after any deferred
+// card marks have been flushed (above) so that any entries that are
+// added to the thread's dirty card queue as a result are not lost.
+if (UseG1GC) {
+flush_barrier_queues();
+}
+#endif // INCLUDE_ALL_GCS
+log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
+exit_type == JavaThread::normal_exit ? "exiting" : "detaching",
+os::current_thread_id());
+// Remove from list of active threads list, and notify VM thread if we are the last non-daemon thread
+Threads::remove(this);
+}
+#if INCLUDE_ALL_GCS
+// Flush G1-related queues.
+void JavaThread::flush_barrier_queues() {
+satb_mark_queue().flush();
+dirty_card_queue().flush();
+}
+void JavaThread::initialize_queues() {
+assert(!SafepointSynchronize::is_at_safepoint(),
+"we should not be at a safepoint");
+SATBMarkQueue& satb_queue = satb_mark_queue();
+SATBMarkQueueSet& satb_queue_set = satb_mark_queue_set();
+// The SATB queue should have been constructed with its active
+// field set to false.
+assert(!satb_queue.is_active(), "SATB queue should not be active");
+assert(satb_queue.is_empty(), "SATB queue should be empty");
+// If we are creating the thread during a marking cycle, we should
+// set the active field of the SATB queue to true.
+if (satb_queue_set.is_active()) {
+satb_queue.set_active(true);
+}
+DirtyCardQueue& dirty_queue = dirty_card_queue();
+// The dirty card queue should have been constructed with its
+// active field set to true.
+assert(dirty_queue.is_active(), "dirty card queue should be active");
+}
+#endif // INCLUDE_ALL_GCS
+void JavaThread::cleanup_failed_attach_current_thread() {
+if (active_handles() != NULL) {
+JNIHandleBlock* block = active_handles();
+set_active_handles(NULL);
+JNIHandleBlock::release_block(block);
+}
+if (free_handle_block() != NULL) {
+JNIHandleBlock* block = free_handle_block();
+set_free_handle_block(NULL);
+JNIHandleBlock::release_block(block);
+}
+// These have to be removed while this is still a valid thread.
+remove_stack_guard_pages();
+if (UseTLAB) {
+tlab().make_parsable(true);  // retire TLAB, if any
+}
+#if INCLUDE_ALL_GCS
+if (UseG1GC) {
+flush_barrier_queues();
+}
+#endif // INCLUDE_ALL_GCS
+Threads::remove(this);
+delete this;
+}
+JavaThread* JavaThread::active() {
+Thread* thread = Thread::current();
+if (thread->is_Java_thread()) {
+return (JavaThread*) thread;
+} else {
+assert(thread->is_VM_thread(), "this must be a vm thread");
+VM_Operation* op = ((VMThread*) thread)->vm_operation();
+JavaThread *ret=op == NULL ? NULL : (JavaThread *)op->calling_thread();
+assert(ret->is_Java_thread(), "must be a Java thread");
+return ret;
+}
+}
+bool JavaThread::is_lock_owned(address adr) const {
+if (Thread::is_lock_owned(adr)) return true;
+for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
+if (chunk->contains(adr)) return true;
+}
+return false;
+}
+void JavaThread::add_monitor_chunk(MonitorChunk* chunk) {
+chunk->set_next(monitor_chunks());
+set_monitor_chunks(chunk);
+}
+void JavaThread::remove_monitor_chunk(MonitorChunk* chunk) {
+guarantee(monitor_chunks() != NULL, "must be non empty");
+if (monitor_chunks() == chunk) {
+set_monitor_chunks(chunk->next());
+} else {
+MonitorChunk* prev = monitor_chunks();
+while (prev->next() != chunk) prev = prev->next();
+prev->set_next(chunk->next());
+}
+}
+// JVM support.
+// Note: this function shouldn't block if it's called in
+// _thread_in_native_trans state (such as from
+// check_special_condition_for_native_trans()).
+void JavaThread::check_and_handle_async_exceptions(bool check_unsafe_error) {
+if (has_last_Java_frame() && has_async_condition()) {
+// If we are at a polling page safepoint (not a poll return)
+// then we must defer async exception because live registers
+// will be clobbered by the exception path. Poll return is
+// ok because the call we a returning from already collides
+// with exception handling registers and so there is no issue.
+// (The exception handling path kills call result registers but
+//  this is ok since the exception kills the result anyway).
+if (is_at_poll_safepoint()) {
+// if the code we are returning to has deoptimized we must defer
+// the exception otherwise live registers get clobbered on the
+// exception path before deoptimization is able to retrieve them.
+//
+RegisterMap map(this, false);
+frame caller_fr = last_frame().sender(&map);
+assert(caller_fr.is_compiled_frame(), "what?");
+if (caller_fr.is_deoptimized_frame()) {
+log_info(exceptions)("deferred async exception at compiled safepoint");
+return;
+}
+}
+}
+JavaThread::AsyncRequests condition = clear_special_runtime_exit_condition();
+if (condition == _no_async_condition) {
+// Conditions have changed since has_special_runtime_exit_condition()
+// was called:
+// - if we were here only because of an external suspend request,
+//   then that was taken care of above (or cancelled) so we are done
+// - if we were here because of another async request, then it has
+//   been cleared between the has_special_runtime_exit_condition()
+//   and now so again we are done
+return;
+}
+// Check for pending async. exception
+if (_pending_async_exception != NULL) {
+// Only overwrite an already pending exception, if it is not a threadDeath.
+if (!has_pending_exception() || !pending_exception()->is_a(SystemDictionary::ThreadDeath_klass())) {
+// We cannot call Exceptions::_throw(...) here because we cannot block
+set_pending_exception(_pending_async_exception, __FILE__, __LINE__);
+LogTarget(Info, exceptions) lt;
+if (lt.is_enabled()) {
+ResourceMark rm;
+LogStream ls(lt);
+ls.print("Async. exception installed at runtime exit (" INTPTR_FORMAT ")", p2i(this));
+if (has_last_Java_frame()) {
+frame f = last_frame();
+ls.print(" (pc: " INTPTR_FORMAT " sp: " INTPTR_FORMAT " )", p2i(f.pc()), p2i(f.sp()));
+}
+ls.print_cr(" of type: %s", _pending_async_exception->klass()->external_name());
+}
+_pending_async_exception = NULL;
+clear_has_async_exception();
+}
+}
+if (check_unsafe_error &&
+condition == _async_unsafe_access_error && !has_pending_exception()) {
+condition = _no_async_condition;  // done
+switch (thread_state()) {
+case _thread_in_vm: {
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
+}
+case _thread_in_native: {
+ThreadInVMfromNative tiv(this);
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in an unsafe memory access operation");
+}
+case _thread_in_Java: {
+ThreadInVMfromJava tiv(this);
+JavaThread* THREAD = this;
+THROW_MSG(vmSymbols::java_lang_InternalError(), "a fault occurred in a recent unsafe memory access operation in compiled Java code");
+}
+default:
+ShouldNotReachHere();
+}
+}
+assert(condition == _no_async_condition || has_pending_exception() ||
+(!check_unsafe_error && condition == _async_unsafe_access_error),
+"must have handled the async condition, if no exception");
+}
+void JavaThread::handle_special_runtime_exit_condition(bool check_asyncs) {
+//
+// Check for pending external suspend. Internal suspend requests do
+// not use handle_special_runtime_exit_condition().
+// If JNIEnv proxies are allowed, don't self-suspend if the target
+// thread is not the current thread. In older versions of jdbx, jdbx
+// threads could call into the VM with another thread's JNIEnv so we
+// can be here operating on behalf of a suspended thread (4432884).
+bool do_self_suspend = is_external_suspend_with_lock();
+if (do_self_suspend && (!AllowJNIEnvProxy || this == JavaThread::current())) {
+//
+// Because thread is external suspended the safepoint code will count
+// thread as at a safepoint. This can be odd because we can be here
+// as _thread_in_Java which would normally transition to _thread_blocked
+// at a safepoint. We would like to mark the thread as _thread_blocked
+// before calling java_suspend_self like all other callers of it but
+// we must then observe proper safepoint protocol. (We can't leave
+// _thread_blocked with a safepoint in progress). However we can be
+// here as _thread_in_native_trans so we can't use a normal transition
+// constructor/destructor pair because they assert on that type of
+// transition. We could do something like:
+//
+// JavaThreadState state = thread_state();
+// set_thread_state(_thread_in_vm);
+// {
+//   ThreadBlockInVM tbivm(this);
+//   java_suspend_self()
+// }
+// set_thread_state(_thread_in_vm_trans);
+// if (safepoint) block;
+// set_thread_state(state);
+//
+// but that is pretty messy. Instead we just go with the way the
+// code has worked before and note that this is the only path to
+// java_suspend_self that doesn't put the thread in _thread_blocked
+// mode.
+frame_anchor()->make_walkable(this);
+java_suspend_self();
+// We might be here for reasons in addition to the self-suspend request
+// so check for other async requests.
+}
+if (check_asyncs) {
+check_and_handle_async_exceptions();
+}
+#if INCLUDE_TRACE
+if (is_trace_suspend()) {
+TRACE_SUSPEND_THREAD(this);
+}
+#endif
+}
+void JavaThread::send_thread_stop(oop java_throwable)  {
+assert(Thread::current()->is_VM_thread(), "should be in the vm thread");
+assert(Threads_lock->is_locked(), "Threads_lock should be locked by safepoint code");
+assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
+// Do not throw asynchronous exceptions against the compiler thread
+// (the compiler thread should not be a Java thread -- fix in 1.4.2)
+if (!can_call_java()) return;
+{
+// Actually throw the Throwable against the target Thread - however
+// only if there is no thread death exception installed already.
+if (_pending_async_exception == NULL || !_pending_async_exception->is_a(SystemDictionary::ThreadDeath_klass())) {
+// If the topmost frame is a runtime stub, then we are calling into
+// OptoRuntime from compiled code. Some runtime stubs (new, monitor_exit..)
+// must deoptimize the caller before continuing, as the compiled  exception handler table
+// may not be valid
+if (has_last_Java_frame()) {
+frame f = last_frame();
+if (f.is_runtime_frame() || f.is_safepoint_blob_frame()) {
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+RegisterMap reg_map(this, UseBiasedLocking);
+frame compiled_frame = f.sender(&reg_map);
+if (!StressCompiledExceptionHandlers && compiled_frame.can_be_deoptimized()) {
+Deoptimization::deoptimize(this, compiled_frame, &reg_map);
+}
+}
+}
+// Set async. pending exception in thread.
+set_pending_async_exception(java_throwable);
+if (log_is_enabled(Info, exceptions)) {
+ResourceMark rm;
+log_info(exceptions)("Pending Async. exception installed of type: %s",
+InstanceKlass::cast(_pending_async_exception->klass())->external_name());
+}
+// for AbortVMOnException flag
+Exceptions::debug_check_abort(_pending_async_exception->klass()->external_name());
+}
+}
+// Interrupt thread so it will wake up from a potential wait()
+Thread::interrupt(this);
+}
+// External suspension mechanism.
+//
+// Tell the VM to suspend a thread when ever it knows that it does not hold on
+// to any VM_locks and it is at a transition
+// Self-suspension will happen on the transition out of the vm.
+// Catch "this" coming in from JNIEnv pointers when the thread has been freed
+//
+// Guarantees on return:
+//   + Target thread will not execute any new bytecode (that's why we need to
+//     force a safepoint)
+//   + Target thread will not enter any new monitors
+//
+void JavaThread::java_suspend() {
+{ MutexLocker mu(Threads_lock);
+if (!Threads::includes(this) || is_exiting() || this->threadObj() == NULL) {
+return;
+}
+}
+{ MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+if (!is_external_suspend()) {
+// a racing resume has cancelled us; bail out now
+return;
+}
+// suspend is done
+uint32_t debug_bits = 0;
+// Warning: is_ext_suspend_completed() may temporarily drop the
+// SR_lock to allow the thread to reach a stable thread state if
+// it is currently in a transient thread state.
+if (is_ext_suspend_completed(false /* !called_by_wait */,
+SuspendRetryDelay, &debug_bits)) {
+return;
+}
+}
+VM_ThreadSuspend vm_suspend;
+VMThread::execute(&vm_suspend);
+}
+// Part II of external suspension.
+// A JavaThread self suspends when it detects a pending external suspend
+// request. This is usually on transitions. It is also done in places
+// where continuing to the next transition would surprise the caller,
+// e.g., monitor entry.
+//
+// Returns the number of times that the thread self-suspended.
+//
+// Note: DO NOT call java_suspend_self() when you just want to block current
+//       thread. java_suspend_self() is the second stage of cooperative
+//       suspension for external suspend requests and should only be used
+//       to complete an external suspend request.
+//
+int JavaThread::java_suspend_self() {
+int ret = 0;
+// we are in the process of exiting so don't suspend
+if (is_exiting()) {
+clear_external_suspend();
+return ret;
+}
+assert(_anchor.walkable() ||
+(is_Java_thread() && !((JavaThread*)this)->has_last_Java_frame()),
+"must have walkable stack");
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+assert(!this->is_ext_suspended(),
+"a thread trying to self-suspend should not already be suspended");
+if (this->is_suspend_equivalent()) {
+// If we are self-suspending as a result of the lifting of a
+// suspend equivalent condition, then the suspend_equivalent
+// flag is not cleared until we set the ext_suspended flag so
+// that wait_for_ext_suspend_completion() returns consistent
+// results.
+this->clear_suspend_equivalent();
+}
+// A racing resume may have cancelled us before we grabbed SR_lock
+// above. Or another external suspend request could be waiting for us
+// by the time we return from SR_lock()->wait(). The thread
+// that requested the suspension may already be trying to walk our
+// stack and if we return now, we can change the stack out from under
+// it. This would be a "bad thing (TM)" and cause the stack walker
+// to crash. We stay self-suspended until there are no more pending
+// external suspend requests.
+while (is_external_suspend()) {
+ret++;
+this->set_ext_suspended();
+// _ext_suspended flag is cleared by java_resume()
+while (is_ext_suspended()) {
+this->SR_lock()->wait(Mutex::_no_safepoint_check_flag);
+}
+}
+return ret;
+}
+#ifdef ASSERT
+// verify the JavaThread has not yet been published in the Threads::list, and
+// hence doesn't need protection from concurrent access at this stage
+void JavaThread::verify_not_published() {
+if (!Threads_lock->owned_by_self()) {
+MutexLockerEx ml(Threads_lock,  Mutex::_no_safepoint_check_flag);
+assert(!Threads::includes(this),
+"java thread shouldn't have been published yet!");
+} else {
+assert(!Threads::includes(this),
+"java thread shouldn't have been published yet!");
+}
+}
+#endif
+// Slow path when the native==>VM/Java barriers detect a safepoint is in
+// progress or when _suspend_flags is non-zero.
+// Current thread needs to self-suspend if there is a suspend request and/or
+// block if a safepoint is in progress.
+// Async exception ISN'T checked.
+// Note only the ThreadInVMfromNative transition can call this function
+// directly and when thread state is _thread_in_native_trans
+void JavaThread::check_safepoint_and_suspend_for_native_trans(JavaThread *thread) {
+assert(thread->thread_state() == _thread_in_native_trans, "wrong state");
+JavaThread *curJT = JavaThread::current();
+bool do_self_suspend = thread->is_external_suspend();
+assert(!curJT->has_last_Java_frame() || curJT->frame_anchor()->walkable(), "Unwalkable stack in native->vm transition");
+// If JNIEnv proxies are allowed, don't self-suspend if the target
+// thread is not the current thread. In older versions of jdbx, jdbx
+// threads could call into the VM with another thread's JNIEnv so we
+// can be here operating on behalf of a suspended thread (4432884).
+if (do_self_suspend && (!AllowJNIEnvProxy || curJT == thread)) {
+JavaThreadState state = thread->thread_state();
+// We mark this thread_blocked state as a suspend-equivalent so
+// that a caller to is_ext_suspend_completed() won't be confused.
+// The suspend-equivalent state is cleared by java_suspend_self().
+thread->set_suspend_equivalent();
+// If the safepoint code sees the _thread_in_native_trans state, it will
+// wait until the thread changes to other thread state. There is no
+// guarantee on how soon we can obtain the SR_lock and complete the
+// self-suspend request. It would be a bad idea to let safepoint wait for
+// too long. Temporarily change the state to _thread_blocked to
+// let the VM thread know that this thread is ready for GC. The problem
+// of changing thread state is that safepoint could happen just after
+// java_suspend_self() returns after being resumed, and VM thread will
+// see the _thread_blocked state. We must check for safepoint
+// after restoring the state and make sure we won't leave while a safepoint
+// is in progress.
+thread->set_thread_state(_thread_blocked);
+thread->java_suspend_self();
+thread->set_thread_state(state);
+InterfaceSupport::serialize_thread_state_with_handler(thread);
+}
+if (SafepointSynchronize::do_call_back()) {
+// If we are safepointing, then block the caller which may not be
+// the same as the target thread (see above).
+SafepointSynchronize::block(curJT);
+}
+if (thread->is_deopt_suspend()) {
+thread->clear_deopt_suspend();
+RegisterMap map(thread, false);
+frame f = thread->last_frame();
+while (f.id() != thread->must_deopt_id() && ! f.is_first_frame()) {
+f = f.sender(&map);
+}
+if (f.id() == thread->must_deopt_id()) {
+thread->clear_must_deopt_id();
+f.deoptimize(thread);
+} else {
+fatal("missed deoptimization!");
+}
+}
+#if INCLUDE_TRACE
+if (thread->is_trace_suspend()) {
+TRACE_SUSPEND_THREAD(thread);
+}
+#endif
+}
+// Slow path when the native==>VM/Java barriers detect a safepoint is in
+// progress or when _suspend_flags is non-zero.
+// Current thread needs to self-suspend if there is a suspend request and/or
+// block if a safepoint is in progress.
+// Also check for pending async exception (not including unsafe access error).
+// Note only the native==>VM/Java barriers can call this function and when
+// thread state is _thread_in_native_trans.
+void JavaThread::check_special_condition_for_native_trans(JavaThread *thread) {
+check_safepoint_and_suspend_for_native_trans(thread);
+if (thread->has_async_exception()) {
+// We are in _thread_in_native_trans state, don't handle unsafe
+// access error since that may block.
+thread->check_and_handle_async_exceptions(false);
+}
+}
+// This is a variant of the normal
+// check_special_condition_for_native_trans with slightly different
+// semantics for use by critical native wrappers.  It does all the
+// normal checks but also performs the transition back into
+// thread_in_Java state.  This is required so that critical natives
+// can potentially block and perform a GC if they are the last thread
+// exiting the GCLocker.
+void JavaThread::check_special_condition_for_native_trans_and_transition(JavaThread *thread) {
+check_special_condition_for_native_trans(thread);
+// Finish the transition
+thread->set_thread_state(_thread_in_Java);
+if (thread->do_critical_native_unlock()) {
+ThreadInVMfromJavaNoAsyncException tiv(thread);
+GCLocker::unlock_critical(thread);
+thread->clear_critical_native_unlock();
+}
+}
+// We need to guarantee the Threads_lock here, since resumes are not
+// allowed during safepoint synchronization
+// Can only resume from an external suspension
+void JavaThread::java_resume() {
+assert_locked_or_safepoint(Threads_lock);
+// Sanity check: thread is gone, has started exiting or the thread
+// was not externally suspended.
+if (!Threads::includes(this) || is_exiting() || !is_external_suspend()) {
+return;
+}
+MutexLockerEx ml(SR_lock(), Mutex::_no_safepoint_check_flag);
+clear_external_suspend();
+if (is_ext_suspended()) {
+clear_ext_suspended();
+SR_lock()->notify_all();
+}
+}
+size_t JavaThread::_stack_red_zone_size = 0;
+size_t JavaThread::_stack_yellow_zone_size = 0;
+size_t JavaThread::_stack_reserved_zone_size = 0;
+size_t JavaThread::_stack_shadow_zone_size = 0;
+void JavaThread::create_stack_guard_pages() {
+if (!os::uses_stack_guard_pages() || _stack_guard_state != stack_guard_unused) { return; }
+address low_addr = stack_end();
+size_t len = stack_guard_zone_size();
+assert(is_aligned(low_addr, os::vm_page_size()), "Stack base should be the start of a page");
+assert(is_aligned(len, os::vm_page_size()), "Stack size should be a multiple of page size");
+int must_commit = os::must_commit_stack_guard_pages();
+// warning("Guarding at " PTR_FORMAT " for len " SIZE_FORMAT "\n", low_addr, len);
+if (must_commit && !os::create_stack_guard_pages((char *) low_addr, len)) {
+log_warning(os, thread)("Attempt to allocate stack guard pages failed.");
+return;
+}
+if (os::guard_memory((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_enabled;
+} else {
+log_warning(os, thread)("Attempt to protect stack guard pages failed ("
+PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
+if (os::uncommit_memory((char *) low_addr, len)) {
+log_warning(os, thread)("Attempt to deallocate stack guard pages failed.");
+}
+return;
+}
+log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages activated: "
+PTR_FORMAT "-" PTR_FORMAT ".",
+os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
+}
+void JavaThread::remove_stack_guard_pages() {
+assert(Thread::current() == this, "from different thread");
+if (_stack_guard_state == stack_guard_unused) return;
+address low_addr = stack_end();
+size_t len = stack_guard_zone_size();
+if (os::must_commit_stack_guard_pages()) {
+if (os::remove_stack_guard_pages((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_unused;
+} else {
+log_warning(os, thread)("Attempt to deallocate stack guard pages failed ("
+PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
+return;
+}
+} else {
+if (_stack_guard_state == stack_guard_unused) return;
+if (os::unguard_memory((char *) low_addr, len)) {
+_stack_guard_state = stack_guard_unused;
+} else {
+log_warning(os, thread)("Attempt to unprotect stack guard pages failed ("
+PTR_FORMAT "-" PTR_FORMAT ").", p2i(low_addr), p2i(low_addr + len));
+return;
+}
+}
+log_debug(os, thread)("Thread " UINTX_FORMAT " stack guard pages removed: "
+PTR_FORMAT "-" PTR_FORMAT ".",
+os::current_thread_id(), p2i(low_addr), p2i(low_addr + len));
+}
+void JavaThread::enable_stack_reserved_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_enabled, "already enabled");
+// The base notation is from the stack's point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_reserved_zone_base() - stack_reserved_zone_size();
+guarantee(base < stack_base(),"Error calculating stack reserved zone");
+guarantee(base < os::current_stack_pointer(),"Error calculating stack reserved zone");
+if (os::guard_memory((char *) base, stack_reserved_zone_size())) {
+_stack_guard_state = stack_guard_enabled;
+} else {
+warning("Attempt to guard stack reserved zone failed.");
+}
+enable_register_stack_guard();
+}
+void JavaThread::disable_stack_reserved_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_reserved_disabled, "already disabled");
+// Simply return if called for a thread that does not use guard pages.
+if (_stack_guard_state == stack_guard_unused) return;
+// The base notation is from the stack's point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_reserved_zone_base() - stack_reserved_zone_size();
+if (os::unguard_memory((char *)base, stack_reserved_zone_size())) {
+_stack_guard_state = stack_guard_reserved_disabled;
+} else {
+warning("Attempt to unguard stack reserved zone failed.");
+}
+disable_register_stack_guard();
+}
+void JavaThread::enable_stack_yellow_reserved_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_enabled, "already enabled");
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_red_zone_base();
+guarantee(base < stack_base(), "Error calculating stack yellow zone");
+guarantee(base < os::current_stack_pointer(), "Error calculating stack yellow zone");
+if (os::guard_memory((char *) base, stack_yellow_reserved_zone_size())) {
+_stack_guard_state = stack_guard_enabled;
+} else {
+warning("Attempt to guard stack yellow zone failed.");
+}
+enable_register_stack_guard();
+}
+void JavaThread::disable_stack_yellow_reserved_zone() {
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+assert(_stack_guard_state != stack_guard_yellow_reserved_disabled, "already disabled");
+// Simply return if called for a thread that does not use guard pages.
+if (_stack_guard_state == stack_guard_unused) return;
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+address base = stack_red_zone_base();
+if (os::unguard_memory((char *)base, stack_yellow_reserved_zone_size())) {
+_stack_guard_state = stack_guard_yellow_reserved_disabled;
+} else {
+warning("Attempt to unguard stack yellow zone failed.");
+}
+disable_register_stack_guard();
+}
+void JavaThread::enable_stack_red_zone() {
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+address base = stack_red_zone_base() - stack_red_zone_size();
+guarantee(base < stack_base(), "Error calculating stack red zone");
+guarantee(base < os::current_stack_pointer(), "Error calculating stack red zone");
+if (!os::guard_memory((char *) base, stack_red_zone_size())) {
+warning("Attempt to guard stack red zone failed.");
+}
+}
+void JavaThread::disable_stack_red_zone() {
+// The base notation is from the stacks point of view, growing downward.
+// We need to adjust it to work correctly with guard_memory()
+assert(_stack_guard_state != stack_guard_unused, "must be using guard pages.");
+address base = stack_red_zone_base() - stack_red_zone_size();
+if (!os::unguard_memory((char *)base, stack_red_zone_size())) {
+warning("Attempt to unguard stack red zone failed.");
+}
+}
+void JavaThread::frames_do(void f(frame*, const RegisterMap* map)) {
+// ignore is there is no stack
+if (!has_last_Java_frame()) return;
+// traverse the stack frames. Starts from top frame.
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+frame* fr = fst.current();
+f(fr, fst.register_map());
+}
+}
+#ifndef PRODUCT
+// Deoptimization
+// Function for testing deoptimization
+void JavaThread::deoptimize() {
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+StackFrameStream fst(this, UseBiasedLocking);
+bool deopt = false;           // Dump stack only if a deopt actually happens.
+bool only_at = strlen(DeoptimizeOnlyAt) > 0;
+// Iterate over all frames in the thread and deoptimize
+for (; !fst.is_done(); fst.next()) {
+if (fst.current()->can_be_deoptimized()) {
+if (only_at) {
+// Deoptimize only at particular bcis.  DeoptimizeOnlyAt
+// consists of comma or carriage return separated numbers so
+// search for the current bci in that string.
+address pc = fst.current()->pc();
+nmethod* nm =  (nmethod*) fst.current()->cb();
+ScopeDesc* sd = nm->scope_desc_at(pc);
+char buffer[8];
+jio_snprintf(buffer, sizeof(buffer), "%d", sd->bci());
+size_t len = strlen(buffer);
+const char * found = strstr(DeoptimizeOnlyAt, buffer);
+while (found != NULL) {
+if ((found[len] == ',' || found[len] == '\n' || found[len] == '\0') &&
+(found == DeoptimizeOnlyAt || found[-1] == ',' || found[-1] == '\n')) {
+// Check that the bci found is bracketed by terminators.
+break;
+}
+found = strstr(found + 1, buffer);
+}
+if (!found) {
+continue;
+}
+}
+if (DebugDeoptimization && !deopt) {
+deopt = true; // One-time only print before deopt
+tty->print_cr("[BEFORE Deoptimization]");
+trace_frames();
+trace_stack();
+}
+Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
+}
+}
+if (DebugDeoptimization && deopt) {
+tty->print_cr("[AFTER Deoptimization]");
+trace_frames();
+}
+}
+// Make zombies
+void JavaThread::make_zombies() {
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+if (fst.current()->can_be_deoptimized()) {
+// it is a Java nmethod
+nmethod* nm = CodeCache::find_nmethod(fst.current()->pc());
+nm->make_not_entrant();
+}
+}
+}
+#endif // PRODUCT
+void JavaThread::deoptimized_wrt_marked_nmethods() {
+if (!has_last_Java_frame()) return;
+// BiasedLocking needs an updated RegisterMap for the revoke monitors pass
+StackFrameStream fst(this, UseBiasedLocking);
+for (; !fst.is_done(); fst.next()) {
+if (fst.current()->should_be_deoptimized()) {
+Deoptimization::deoptimize(this, *fst.current(), fst.register_map());
+}
+}
+}
+// If the caller is a NamedThread, then remember, in the current scope,
+// the given JavaThread in its _processed_thread field.
+class RememberProcessedThread: public StackObj {
+NamedThread* _cur_thr;
+public:
+RememberProcessedThread(JavaThread* jthr) {
+Thread* thread = Thread::current();
+if (thread->is_Named_thread()) {
+_cur_thr = (NamedThread *)thread;
+_cur_thr->set_processed_thread(jthr);
+} else {
+_cur_thr = NULL;
+}
+}
+~RememberProcessedThread() {
+if (_cur_thr) {
+_cur_thr->set_processed_thread(NULL);
+}
+}
+};
+void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
+// Verify that the deferred card marks have been flushed.
+assert(deferred_card_mark().is_empty(), "Should be empty during GC");
+// Traverse the GCHandles
+Thread::oops_do(f, cf);
+JVMCI_ONLY(f->do_oop((oop*)&_pending_failed_speculation);)
+assert((!has_last_Java_frame() && java_call_counter() == 0) ||
+(has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
+if (has_last_Java_frame()) {
+// Record JavaThread to GC thread
+RememberProcessedThread rpt(this);
+// Traverse the privileged stack
+if (_privileged_stack_top != NULL) {
+_privileged_stack_top->oops_do(f);
+}
+// traverse the registered growable array
+if (_array_for_gc != NULL) {
+for (int index = 0; index < _array_for_gc->length(); index++) {
+f->do_oop(_array_for_gc->adr_at(index));
+}
+}
+// Traverse the monitor chunks
+for (MonitorChunk* chunk = monitor_chunks(); chunk != NULL; chunk = chunk->next()) {
+chunk->oops_do(f);
+}
+// Traverse the execution stack
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+fst.current()->oops_do(f, cf, fst.register_map());
+}
+}
+// callee_target is never live across a gc point so NULL it here should
+// it still contain a methdOop.
+set_callee_target(NULL);
+assert(vframe_array_head() == NULL, "deopt in progress at a safepoint!");
+// If we have deferred set_locals there might be oops waiting to be
+// written
+GrowableArray<jvmtiDeferredLocalVariableSet*>* list = deferred_locals();
+if (list != NULL) {
+for (int i = 0; i < list->length(); i++) {
+list->at(i)->oops_do(f);
+}
+}
+// Traverse instance variables at the end since the GC may be moving things
+// around using this function
+f->do_oop((oop*) &_threadObj);
+f->do_oop((oop*) &_vm_result);
+f->do_oop((oop*) &_exception_oop);
+f->do_oop((oop*) &_pending_async_exception);
+if (jvmti_thread_state() != NULL) {
+jvmti_thread_state()->oops_do(f);
+}
+}
+void JavaThread::nmethods_do(CodeBlobClosure* cf) {
+assert((!has_last_Java_frame() && java_call_counter() == 0) ||
+(has_last_Java_frame() && java_call_counter() > 0), "wrong java_sp info!");
+if (has_last_Java_frame()) {
+// Traverse the execution stack
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+fst.current()->nmethods_do(cf);
+}
+}
+}
+void JavaThread::metadata_do(void f(Metadata*)) {
+if (has_last_Java_frame()) {
+// Traverse the execution stack to call f() on the methods in the stack
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+fst.current()->metadata_do(f);
+}
+} else if (is_Compiler_thread()) {
+// need to walk ciMetadata in current compile tasks to keep alive.
+CompilerThread* ct = (CompilerThread*)this;
+if (ct->env() != NULL) {
+ct->env()->metadata_do(f);
+}
+if (ct->task() != NULL) {
+ct->task()->metadata_do(f);
+}
+}
+}
+// Printing
+const char* _get_thread_state_name(JavaThreadState _thread_state) {
+switch (_thread_state) {
+case _thread_uninitialized:     return "_thread_uninitialized";
+case _thread_new:               return "_thread_new";
+case _thread_new_trans:         return "_thread_new_trans";
+case _thread_in_native:         return "_thread_in_native";
+case _thread_in_native_trans:   return "_thread_in_native_trans";
+case _thread_in_vm:             return "_thread_in_vm";
+case _thread_in_vm_trans:       return "_thread_in_vm_trans";
+case _thread_in_Java:           return "_thread_in_Java";
+case _thread_in_Java_trans:     return "_thread_in_Java_trans";
+case _thread_blocked:           return "_thread_blocked";
+case _thread_blocked_trans:     return "_thread_blocked_trans";
+default:                        return "unknown thread state";
+}
+}
+#ifndef PRODUCT
+void JavaThread::print_thread_state_on(outputStream *st) const {
+st->print_cr("   JavaThread state: %s", _get_thread_state_name(_thread_state));
+};
+void JavaThread::print_thread_state() const {
+print_thread_state_on(tty);
+}
+#endif // PRODUCT
+// Called by Threads::print() for VM_PrintThreads operation
+void JavaThread::print_on(outputStream *st) const {
+st->print_raw("\"");
+st->print_raw(get_thread_name());
+st->print_raw("\" ");
+oop thread_oop = threadObj();
+if (thread_oop != NULL) {
+st->print("#" INT64_FORMAT " ", (int64_t)java_lang_Thread::thread_id(thread_oop));
+if (java_lang_Thread::is_daemon(thread_oop))  st->print("daemon ");
+st->print("prio=%d ", java_lang_Thread::priority(thread_oop));
+}
+Thread::print_on(st);
+// print guess for valid stack memory region (assume 4K pages); helps lock debugging
+st->print_cr("[" INTPTR_FORMAT "]", (intptr_t)last_Java_sp() & ~right_n_bits(12));
+if (thread_oop != NULL) {
+st->print_cr("   java.lang.Thread.State: %s", java_lang_Thread::thread_status_name(thread_oop));
+}
+#ifndef PRODUCT
+print_thread_state_on(st);
+_safepoint_state->print_on(st);
+#endif // PRODUCT
+if (is_Compiler_thread()) {
+CompilerThread* ct = (CompilerThread*)this;
+if (ct->task() != NULL) {
+st->print("   Compiling: ");
+ct->task()->print(st, NULL, true, false);
+} else {
+st->print("   No compile task");
+}
+st->cr();
+}
+}
+void JavaThread::print_name_on_error(outputStream* st, char *buf, int buflen) const {
+st->print("%s", get_thread_name_string(buf, buflen));
+}
+// Called by fatal error handler. The difference between this and
+// JavaThread::print() is that we can't grab lock or allocate memory.
+void JavaThread::print_on_error(outputStream* st, char *buf, int buflen) const {
+st->print("JavaThread \"%s\"", get_thread_name_string(buf, buflen));
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+if (java_lang_Thread::is_daemon(thread_obj)) st->print(" daemon");
+}
+st->print(" [");
+st->print("%s", _get_thread_state_name(_thread_state));
+if (osthread()) {
+st->print(", id=%d", osthread()->thread_id());
+}
+st->print(", stack(" PTR_FORMAT "," PTR_FORMAT ")",
+p2i(stack_end()), p2i(stack_base()));
+st->print("]");
+return;
+}
+// Verification
+static void frame_verify(frame* f, const RegisterMap *map) { f->verify(map); }
+void JavaThread::verify() {
+// Verify oops in the thread.
+oops_do(&VerifyOopClosure::verify_oop, NULL);
+// Verify the stack frames.
+frames_do(frame_verify);
+}
+// CR 6300358 (sub-CR 2137150)
+// Most callers of this method assume that it can't return NULL but a
+// thread may not have a name whilst it is in the process of attaching to
+// the VM - see CR 6412693, and there are places where a JavaThread can be
+// seen prior to having it's threadObj set (eg JNI attaching threads and
+// if vm exit occurs during initialization). These cases can all be accounted
+// for such that this method never returns NULL.
+const char* JavaThread::get_thread_name() const {
+#ifdef ASSERT
+// early safepoints can hit while current thread does not yet have TLS
+if (!SafepointSynchronize::is_at_safepoint()) {
+Thread *cur = Thread::current();
+if (!(cur->is_Java_thread() && cur == this)) {
+// Current JavaThreads are allowed to get their own name without
+// the Threads_lock.
+assert_locked_or_safepoint(Threads_lock);
+}
+}
+#endif // ASSERT
+return get_thread_name_string();
+}
+// Returns a non-NULL representation of this thread's name, or a suitable
+// descriptive string if there is no set name
+const char* JavaThread::get_thread_name_string(char* buf, int buflen) const {
+const char* name_str;
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+oop name = java_lang_Thread::name(thread_obj);
+if (name != NULL) {
+if (buf == NULL) {
+name_str = java_lang_String::as_utf8_string(name);
+} else {
+name_str = java_lang_String::as_utf8_string(name, buf, buflen);
+}
+} else if (is_attaching_via_jni()) { // workaround for 6412693 - see 6404306
+name_str = "<no-name - thread is attaching>";
+} else {
+name_str = Thread::name();
+}
+} else {
+name_str = Thread::name();
+}
+assert(name_str != NULL, "unexpected NULL thread name");
+return name_str;
+}
+const char* JavaThread::get_threadgroup_name() const {
+debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+oop thread_group = java_lang_Thread::threadGroup(thread_obj);
+if (thread_group != NULL) {
+// ThreadGroup.name can be null
+return java_lang_ThreadGroup::name(thread_group);
+}
+}
+return NULL;
+}
+const char* JavaThread::get_parent_name() const {
+debug_only(if (JavaThread::current() != this) assert_locked_or_safepoint(Threads_lock);)
+oop thread_obj = threadObj();
+if (thread_obj != NULL) {
+oop thread_group = java_lang_Thread::threadGroup(thread_obj);
+if (thread_group != NULL) {
+oop parent = java_lang_ThreadGroup::parent(thread_group);
+if (parent != NULL) {
+// ThreadGroup.name can be null
+return java_lang_ThreadGroup::name(parent);
+}
+}
+}
+return NULL;
+}
+ThreadPriority JavaThread::java_priority() const {
+oop thr_oop = threadObj();
+if (thr_oop == NULL) return NormPriority; // Bootstrapping
+ThreadPriority priority = java_lang_Thread::priority(thr_oop);
+assert(MinPriority <= priority && priority <= MaxPriority, "sanity check");
+return priority;
+}
+void JavaThread::prepare(jobject jni_thread, ThreadPriority prio) {
+assert(Threads_lock->owner() == Thread::current(), "must have threads lock");
+// Link Java Thread object <-> C++ Thread
+// Get the C++ thread object (an oop) from the JNI handle (a jthread)
+// and put it into a new Handle.  The Handle "thread_oop" can then
+// be used to pass the C++ thread object to other methods.
+// Set the Java level thread object (jthread) field of the
+// new thread (a JavaThread *) to C++ thread object using the
+// "thread_oop" handle.
+// Set the thread field (a JavaThread *) of the
+// oop representing the java_lang_Thread to the new thread (a JavaThread *).
+Handle thread_oop(Thread::current(),
+JNIHandles::resolve_non_null(jni_thread));
+assert(InstanceKlass::cast(thread_oop->klass())->is_linked(),
+"must be initialized");
+set_threadObj(thread_oop());
+java_lang_Thread::set_thread(thread_oop(), this);
+if (prio == NoPriority) {
+prio = java_lang_Thread::priority(thread_oop());
+assert(prio != NoPriority, "A valid priority should be present");
+}
+// Push the Java priority down to the native thread; needs Threads_lock
+Thread::set_priority(this, prio);
+prepare_ext();
+// Add the new thread to the Threads list and set it in motion.
+// We must have threads lock in order to call Threads::add.
+// It is crucial that we do not block before the thread is
+// added to the Threads list for if a GC happens, then the java_thread oop
+// will not be visited by GC.
+Threads::add(this);
+}
+oop JavaThread::current_park_blocker() {
+// Support for JSR-166 locks
+oop thread_oop = threadObj();
+if (thread_oop != NULL &&
+JDK_Version::current().supports_thread_park_blocker()) {
+return java_lang_Thread::park_blocker(thread_oop);
+}
+return NULL;
+}
+void JavaThread::print_stack_on(outputStream* st) {
+if (!has_last_Java_frame()) return;
+ResourceMark rm;
+HandleMark   hm;
+RegisterMap reg_map(this);
+vframe* start_vf = last_java_vframe(&reg_map);
+int count = 0;
+for (vframe* f = start_vf; f; f = f->sender()) {
+if (f->is_java_frame()) {
+javaVFrame* jvf = javaVFrame::cast(f);
+java_lang_Throwable::print_stack_element(st, jvf->method(), jvf->bci());
+// Print out lock information
+if (JavaMonitorsInStackTrace) {
+jvf->print_lock_info_on(st, count);
+}
+} else {
+// Ignore non-Java frames
+}
+// Bail-out case for too deep stacks
+count++;
+if (MaxJavaStackTraceDepth == count) return;
+}
+}
+// JVMTI PopFrame support
+void JavaThread::popframe_preserve_args(ByteSize size_in_bytes, void* start) {
+assert(_popframe_preserved_args == NULL, "should not wipe out old PopFrame preserved arguments");
+if (in_bytes(size_in_bytes) != 0) {
+_popframe_preserved_args = NEW_C_HEAP_ARRAY(char, in_bytes(size_in_bytes), mtThread);
+_popframe_preserved_args_size = in_bytes(size_in_bytes);
+Copy::conjoint_jbytes(start, _popframe_preserved_args, _popframe_preserved_args_size);
+}
+}
+void* JavaThread::popframe_preserved_args() {
+return _popframe_preserved_args;
+}
+ByteSize JavaThread::popframe_preserved_args_size() {
+return in_ByteSize(_popframe_preserved_args_size);
+}
+WordSize JavaThread::popframe_preserved_args_size_in_words() {
+int sz = in_bytes(popframe_preserved_args_size());
+assert(sz % wordSize == 0, "argument size must be multiple of wordSize");
+return in_WordSize(sz / wordSize);
+}
+void JavaThread::popframe_free_preserved_args() {
+assert(_popframe_preserved_args != NULL, "should not free PopFrame preserved arguments twice");
+FREE_C_HEAP_ARRAY(char, (char*) _popframe_preserved_args);
+_popframe_preserved_args = NULL;
+_popframe_preserved_args_size = 0;
+}
+#ifndef PRODUCT
+void JavaThread::trace_frames() {
+tty->print_cr("[Describe stack]");
+int frame_no = 1;
+for (StackFrameStream fst(this); !fst.is_done(); fst.next()) {
+tty->print("  %d. ", frame_no++);
+fst.current()->print_value_on(tty, this);
+tty->cr();
+}
+}
+class PrintAndVerifyOopClosure: public OopClosure {
+protected:
+template <class T> inline void do_oop_work(T* p) {
+oop obj = oopDesc::load_decode_heap_oop(p);
+if (obj == NULL) return;
+tty->print(INTPTR_FORMAT ": ", p2i(p));
+if (oopDesc::is_oop_or_null(obj)) {
+if (obj->is_objArray()) {
+tty->print_cr("valid objArray: " INTPTR_FORMAT, p2i(obj));
+} else {
+obj->print();
+}
+} else {
+tty->print_cr("invalid oop: " INTPTR_FORMAT, p2i(obj));
+}
+tty->cr();
+}
+public:
+virtual void do_oop(oop* p) { do_oop_work(p); }
+virtual void do_oop(narrowOop* p)  { do_oop_work(p); }
+};
+static void oops_print(frame* f, const RegisterMap *map) {
+PrintAndVerifyOopClosure print;
+f->print_value();
+f->oops_do(&print, NULL, (RegisterMap*)map);
+}
+// Print our all the locations that contain oops and whether they are
+// valid or not.  This useful when trying to find the oldest frame
+// where an oop has gone bad since the frame walk is from youngest to
+// oldest.
+void JavaThread::trace_oops() {
+tty->print_cr("[Trace oops]");
+frames_do(oops_print);
+}
+#ifdef ASSERT
+// Print or validate the layout of stack frames
+void JavaThread::print_frame_layout(int depth, bool validate_only) {
+ResourceMark rm;
+PRESERVE_EXCEPTION_MARK;
+FrameValues values;
+int frame_no = 0;
+for (StackFrameStream fst(this, false); !fst.is_done(); fst.next()) {
+fst.current()->describe(values, ++frame_no);
+if (depth == frame_no) break;
+}
+if (validate_only) {
+values.validate();
+} else {
+tty->print_cr("[Describe stack layout]");
+values.print(this);
+}
+}
+#endif
+void JavaThread::trace_stack_from(vframe* start_vf) {
+ResourceMark rm;
+int vframe_no = 1;
+for (vframe* f = start_vf; f; f = f->sender()) {
+if (f->is_java_frame()) {
+javaVFrame::cast(f)->print_activation(vframe_no++);
+} else {
+f->print();
+}
+if (vframe_no > StackPrintLimit) {
+tty->print_cr("...<more frames>...");
+return;
+}
+}
+}
+void JavaThread::trace_stack() {
+if (!has_last_Java_frame()) return;
+ResourceMark rm;
+HandleMark   hm;
+RegisterMap reg_map(this);
+trace_stack_from(last_java_vframe(&reg_map));
+}
+#endif // PRODUCT
+javaVFrame* JavaThread::last_java_vframe(RegisterMap *reg_map) {
+assert(reg_map != NULL, "a map must be given");
+frame f = last_frame();
+for (vframe* vf = vframe::new_vframe(&f, reg_map, this); vf; vf = vf->sender()) {
+if (vf->is_java_frame()) return javaVFrame::cast(vf);
+}
+return NULL;
+}
+Klass* JavaThread::security_get_caller_class(int depth) {
+vframeStream vfst(this);
+vfst.security_get_caller_frame(depth);
+if (!vfst.at_end()) {
+return vfst.method()->method_holder();
+}
+return NULL;
+}
+static void compiler_thread_entry(JavaThread* thread, TRAPS) {
+assert(thread->is_Compiler_thread(), "must be compiler thread");
+CompileBroker::compiler_thread_loop();
+}
+static void sweeper_thread_entry(JavaThread* thread, TRAPS) {
+NMethodSweeper::sweeper_loop();
+}
+// Create a CompilerThread
+CompilerThread::CompilerThread(CompileQueue* queue,
+CompilerCounters* counters)
+: JavaThread(&compiler_thread_entry) {
+_env   = NULL;
+_log   = NULL;
+_task  = NULL;
+_queue = queue;
+_counters = counters;
+_buffer_blob = NULL;
+_compiler = NULL;
+#ifndef PRODUCT
+_ideal_graph_printer = NULL;
+#endif
+}
+bool CompilerThread::can_call_java() const {
+return _compiler != NULL && _compiler->is_jvmci();
+}
+// Create sweeper thread
+CodeCacheSweeperThread::CodeCacheSweeperThread()
+: JavaThread(&sweeper_thread_entry) {
+_scanned_compiled_method = NULL;
+}
+void CodeCacheSweeperThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
+JavaThread::oops_do(f, cf);
+if (_scanned_compiled_method != NULL && cf != NULL) {
+// Safepoints can occur when the sweeper is scanning an nmethod so
+// process it here to make sure it isn't unloaded in the middle of
+// a scan.
+cf->do_code_blob(_scanned_compiled_method);
+}
+}
+void CodeCacheSweeperThread::nmethods_do(CodeBlobClosure* cf) {
+JavaThread::nmethods_do(cf);
+if (_scanned_compiled_method != NULL && cf != NULL) {
+// Safepoints can occur when the sweeper is scanning an nmethod so
+// process it here to make sure it isn't unloaded in the middle of
+// a scan.
+cf->do_code_blob(_scanned_compiled_method);
+}
+}
+// ======= Threads ========
+// The Threads class links together all active threads, and provides
+// operations over all threads.  It is protected by its own Mutex
+// lock, which is also used in other contexts to protect thread
+// operations from having the thread being operated on from exiting
+// and going away unexpectedly (e.g., safepoint synchronization)
+JavaThread* Threads::_thread_list = NULL;
+int         Threads::_number_of_threads = 0;
+int         Threads::_number_of_non_daemon_threads = 0;
+int         Threads::_return_code = 0;
+int         Threads::_thread_claim_parity = 0;
+size_t      JavaThread::_stack_size_at_create = 0;
+#ifdef ASSERT
+bool        Threads::_vm_complete = false;
+#endif
+// All JavaThreads
+#define ALL_JAVA_THREADS(X) for (JavaThread* X = _thread_list; X; X = X->next())
+// All JavaThreads + all non-JavaThreads (i.e., every thread in the system)
+void Threads::threads_do(ThreadClosure* tc) {
+assert_locked_or_safepoint(Threads_lock);
+// ALL_JAVA_THREADS iterates through all JavaThreads
+ALL_JAVA_THREADS(p) {
+tc->do_thread(p);
+}
+// Someday we could have a table or list of all non-JavaThreads.
+// For now, just manually iterate through them.
+tc->do_thread(VMThread::vm_thread());
+Universe::heap()->gc_threads_do(tc);
+WatcherThread *wt = WatcherThread::watcher_thread();
+// Strictly speaking, the following NULL check isn't sufficient to make sure
+// the data for WatcherThread is still valid upon being examined. However,
+// considering that WatchThread terminates when the VM is on the way to
+// exit at safepoint, the chance of the above is extremely small. The right
+// way to prevent termination of WatcherThread would be to acquire
+// Terminator_lock, but we can't do that without violating the lock rank
+// checking in some cases.
+if (wt != NULL) {
+tc->do_thread(wt);
+}
+// If CompilerThreads ever become non-JavaThreads, add them here
+}
+void Threads::parallel_java_threads_do(ThreadClosure* tc) {
+int cp = Threads::thread_claim_parity();
+ALL_JAVA_THREADS(p) {
+if (p->claim_oops_do(true, cp)) {
+tc->do_thread(p);
+}
+}
+// Thread claiming protocol requires us to claim the same interesting
+// threads on all paths. Notably, Threads::possibly_parallel_threads_do
+// claims all Java threads *and* the VMThread. To avoid breaking the
+// claiming protocol, we have to claim VMThread on this path too, even
+// if we do not apply the closure to the VMThread.
+VMThread* vmt = VMThread::vm_thread();
+(void)vmt->claim_oops_do(true, cp);
+}
+// The system initialization in the library has three phases.
+//
+// Phase 1: java.lang.System class initialization
+//     java.lang.System is a primordial class loaded and initialized
+//     by the VM early during startup.  java.lang.System.<clinit>
+//     only does registerNatives and keeps the rest of the class
+//     initialization work later until thread initialization completes.
+//
+//     System.initPhase1 initializes the system properties, the static
+//     fields in, out, and err. Set up java signal handlers, OS-specific
+//     system settings, and thread group of the main thread.
+static void call_initPhase1(TRAPS) {
+Klass* klass =  SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result, klass, vmSymbols::initPhase1_name(),
+vmSymbols::void_method_signature(), CHECK);
+}
+// Phase 2. Module system initialization
+//     This will initialize the module system.  Only java.base classes
+//     can be loaded until phase 2 completes.
+//
+//     Call System.initPhase2 after the compiler initialization and jsr292
+//     classes get initialized because module initialization runs a lot of java
+//     code, that for performance reasons, should be compiled.  Also, this will
+//     enable the startup code to use lambda and other language features in this
+//     phase and onward.
+//
+//     After phase 2, The VM will begin search classes from -Xbootclasspath/a.
+static void call_initPhase2(TRAPS) {
+TraceTime timer("Initialize module system", TRACETIME_LOG(Info, startuptime));
+Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
+JavaValue result(T_INT);
+JavaCallArguments args;
+args.push_int(DisplayVMOutputToStderr);
+args.push_int(log_is_enabled(Debug, init)); // print stack trace if exception thrown
+JavaCalls::call_static(&result, klass, vmSymbols::initPhase2_name(),
+vmSymbols::boolean_boolean_int_signature(), &args, CHECK);
+if (result.get_jint() != JNI_OK) {
+vm_exit_during_initialization(); // no message or exception
+}
+universe_post_module_init();
+}
+// Phase 3. final setup - set security manager, system class loader and TCCL
+//
+//     This will instantiate and set the security manager, set the system class
+//     loader as well as the thread context class loader.  The security manager
+//     and system class loader may be a custom class loaded from -Xbootclasspath/a,
+//     other modules or the application's classpath.
+static void call_initPhase3(TRAPS) {
+Klass* klass = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_System(), true, CHECK);
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result, klass, vmSymbols::initPhase3_name(),
+vmSymbols::void_method_signature(), CHECK);
+}
+void Threads::initialize_java_lang_classes(JavaThread* main_thread, TRAPS) {
+TraceTime timer("Initialize java.lang classes", TRACETIME_LOG(Info, startuptime));
+if (EagerXrunInit && Arguments::init_libraries_at_startup()) {
+create_vm_init_libraries();
+}
+initialize_class(vmSymbols::java_lang_String(), CHECK);
+// Inject CompactStrings value after the static initializers for String ran.
+java_lang_String::set_compact_strings(CompactStrings);
+// Initialize java_lang.System (needed before creating the thread)
+initialize_class(vmSymbols::java_lang_System(), CHECK);
+// The VM creates & returns objects of this class. Make sure it's initialized.
+initialize_class(vmSymbols::java_lang_Class(), CHECK);
+initialize_class(vmSymbols::java_lang_ThreadGroup(), CHECK);
+Handle thread_group = create_initial_thread_group(CHECK);
+Universe::set_main_thread_group(thread_group());
+initialize_class(vmSymbols::java_lang_Thread(), CHECK);
+oop thread_object = create_initial_thread(thread_group, main_thread, CHECK);
+main_thread->set_threadObj(thread_object);
+// Set thread status to running since main thread has
+// been started and running.
+java_lang_Thread::set_thread_status(thread_object,
+java_lang_Thread::RUNNABLE);
+// The VM creates objects of this class.
+initialize_class(vmSymbols::java_lang_Module(), CHECK);
+// The VM preresolves methods to these classes. Make sure that they get initialized
+initialize_class(vmSymbols::java_lang_reflect_Method(), CHECK);
+initialize_class(vmSymbols::java_lang_ref_Finalizer(), CHECK);
+// Phase 1 of the system initialization in the library, java.lang.System class initialization
+call_initPhase1(CHECK);
+// get the Java runtime name after java.lang.System is initialized
+JDK_Version::set_runtime_name(get_java_runtime_name(THREAD));
+JDK_Version::set_runtime_version(get_java_runtime_version(THREAD));
+// an instance of OutOfMemory exception has been allocated earlier
+initialize_class(vmSymbols::java_lang_OutOfMemoryError(), CHECK);
+initialize_class(vmSymbols::java_lang_NullPointerException(), CHECK);
+initialize_class(vmSymbols::java_lang_ClassCastException(), CHECK);
+initialize_class(vmSymbols::java_lang_ArrayStoreException(), CHECK);
+initialize_class(vmSymbols::java_lang_ArithmeticException(), CHECK);
+initialize_class(vmSymbols::java_lang_StackOverflowError(), CHECK);
+initialize_class(vmSymbols::java_lang_IllegalMonitorStateException(), CHECK);
+initialize_class(vmSymbols::java_lang_IllegalArgumentException(), CHECK);
+}
+void Threads::initialize_jsr292_core_classes(TRAPS) {
+TraceTime timer("Initialize java.lang.invoke classes", TRACETIME_LOG(Info, startuptime));
+initialize_class(vmSymbols::java_lang_invoke_MethodHandle(), CHECK);
+initialize_class(vmSymbols::java_lang_invoke_ResolvedMethodName(), CHECK);
+initialize_class(vmSymbols::java_lang_invoke_MemberName(), CHECK);
+initialize_class(vmSymbols::java_lang_invoke_MethodHandleNatives(), CHECK);
+}
+jint Threads::create_vm(JavaVMInitArgs* args, bool* canTryAgain) {
+extern void JDK_Version_init();
+// Preinitialize version info.
+VM_Version::early_initialize();
+// Check version
+if (!is_supported_jni_version(args->version)) return JNI_EVERSION;
+// Initialize library-based TLS
+ThreadLocalStorage::init();
+// Initialize the output stream module
+ostream_init();
+// Process java launcher properties.
+Arguments::process_sun_java_launcher_properties(args);
+// Initialize the os module
+os::init();
+// Record VM creation timing statistics
+TraceVmCreationTime create_vm_timer;
+create_vm_timer.start();
+// Initialize system properties.
+Arguments::init_system_properties();
+// So that JDK version can be used as a discriminator when parsing arguments
+JDK_Version_init();
+// Update/Initialize System properties after JDK version number is known
+Arguments::init_version_specific_system_properties();
+// Make sure to initialize log configuration *before* parsing arguments
+LogConfiguration::initialize(create_vm_timer.begin_time());
+// Parse arguments
+jint parse_result = Arguments::parse(args);
+if (parse_result != JNI_OK) return parse_result;
+os::init_before_ergo();
+jint ergo_result = Arguments::apply_ergo();
+if (ergo_result != JNI_OK) return ergo_result;
+// Final check of all ranges after ergonomics which may change values.
+if (!CommandLineFlagRangeList::check_ranges()) {
+return JNI_EINVAL;
+}
+// Final check of all 'AfterErgo' constraints after ergonomics which may change values.
+bool constraint_result = CommandLineFlagConstraintList::check_constraints(CommandLineFlagConstraint::AfterErgo);
+if (!constraint_result) {
+return JNI_EINVAL;
+}
+CommandLineFlagWriteableList::mark_startup();
+if (PauseAtStartup) {
+os::pause();
+}
+HOTSPOT_VM_INIT_BEGIN();
+// Timing (must come after argument parsing)
+TraceTime timer("Create VM", TRACETIME_LOG(Info, startuptime));
+// Initialize the os module after parsing the args
+jint os_init_2_result = os::init_2();
+if (os_init_2_result != JNI_OK) return os_init_2_result;
+jint adjust_after_os_result = Arguments::adjust_after_os();
+if (adjust_after_os_result != JNI_OK) return adjust_after_os_result;
+// Initialize output stream logging
+ostream_init_log();
+// Convert -Xrun to -agentlib: if there is no JVM_OnLoad
+// Must be before create_vm_init_agents()
+if (Arguments::init_libraries_at_startup()) {
+convert_vm_init_libraries_to_agents();
+}
+// Launch -agentlib/-agentpath and converted -Xrun agents
+if (Arguments::init_agents_at_startup()) {
+create_vm_init_agents();
+}
+// Initialize Threads state
+_thread_list = NULL;
+_number_of_threads = 0;
+_number_of_non_daemon_threads = 0;
+// Initialize global data structures and create system classes in heap
+vm_init_globals();
+#if INCLUDE_JVMCI
+if (JVMCICounterSize > 0) {
+JavaThread::_jvmci_old_thread_counters = NEW_C_HEAP_ARRAY(jlong, JVMCICounterSize, mtInternal);
+memset(JavaThread::_jvmci_old_thread_counters, 0, sizeof(jlong) * JVMCICounterSize);
+} else {
+JavaThread::_jvmci_old_thread_counters = NULL;
+}
+#endif // INCLUDE_JVMCI
+// Attach the main thread to this os thread
+JavaThread* main_thread = new JavaThread();
+main_thread->set_thread_state(_thread_in_vm);
+main_thread->initialize_thread_current();
+// must do this before set_active_handles
+main_thread->record_stack_base_and_size();
+main_thread->set_active_handles(JNIHandleBlock::allocate_block());
+if (!main_thread->set_as_starting_thread()) {
+vm_shutdown_during_initialization(
+"Failed necessary internal allocation. Out of swap space");
+delete main_thread;
+*canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
+return JNI_ENOMEM;
+}
+// Enable guard page *after* os::create_main_thread(), otherwise it would
+// crash Linux VM, see notes in os_linux.cpp.
+main_thread->create_stack_guard_pages();
+// Initialize Java-Level synchronization subsystem
+ObjectMonitor::Initialize();
+// Initialize global modules
+jint status = init_globals();
+if (status != JNI_OK) {
+delete main_thread;
+*canTryAgain = false; // don't let caller call JNI_CreateJavaVM again
+return status;
+}
+if (TRACE_INITIALIZE() != JNI_OK) {
+vm_exit_during_initialization("Failed to initialize tracing backend");
+}
+// Should be done after the heap is fully created
+main_thread->cache_global_variables();
+HandleMark hm;
+{ MutexLocker mu(Threads_lock);
+Threads::add(main_thread);
+}
+// Any JVMTI raw monitors entered in onload will transition into
+// real raw monitor. VM is setup enough here for raw monitor enter.
+JvmtiExport::transition_pending_onload_raw_monitors();
+// Create the VMThread
+{ TraceTime timer("Start VMThread", TRACETIME_LOG(Info, startuptime));
+VMThread::create();
+Thread* vmthread = VMThread::vm_thread();
+if (!os::create_thread(vmthread, os::vm_thread)) {
+vm_exit_during_initialization("Cannot create VM thread. "
+"Out of system resources.");
+}
+// Wait for the VM thread to become ready, and VMThread::run to initialize
+// Monitors can have spurious returns, must always check another state flag
+{
+MutexLocker ml(Notify_lock);
+os::start_thread(vmthread);
+while (vmthread->active_handles() == NULL) {
+Notify_lock->wait();
+}
+}
+}
+assert(Universe::is_fully_initialized(), "not initialized");
+if (VerifyDuringStartup) {
+// Make sure we're starting with a clean slate.
+VM_Verify verify_op;
+VMThread::execute(&verify_op);
+}
+Thread* THREAD = Thread::current();
+// Always call even when there are not JVMTI environments yet, since environments
+// may be attached late and JVMTI must track phases of VM execution
+JvmtiExport::enter_early_start_phase();
+// Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
+JvmtiExport::post_early_vm_start();
+initialize_java_lang_classes(main_thread, CHECK_JNI_ERR);
+// We need this for ClassDataSharing - the initial vm.info property is set
+// with the default value of CDS "sharing" which may be reset through
+// command line options.
+reset_vm_info_property(CHECK_JNI_ERR);
+quicken_jni_functions();
+// No more stub generation allowed after that point.
+StubCodeDesc::freeze();
+// Set flag that basic initialization has completed. Used by exceptions and various
+// debug stuff, that does not work until all basic classes have been initialized.
+set_init_completed();
+LogConfiguration::post_initialize();
+Metaspace::post_initialize();
+HOTSPOT_VM_INIT_END();
+// record VM initialization completion time
+#if INCLUDE_MANAGEMENT
+Management::record_vm_init_completed();
+#endif // INCLUDE_MANAGEMENT
+// Signal Dispatcher needs to be started before VMInit event is posted
+os::signal_init(CHECK_JNI_ERR);
+// Start Attach Listener if +StartAttachListener or it can't be started lazily
+if (!DisableAttachMechanism) {
+AttachListener::vm_start();
+if (StartAttachListener || AttachListener::init_at_startup()) {
+AttachListener::init();
+}
+}
+// Launch -Xrun agents
+// Must be done in the JVMTI live phase so that for backward compatibility the JDWP
+// back-end can launch with -Xdebug -Xrunjdwp.
+if (!EagerXrunInit && Arguments::init_libraries_at_startup()) {
+create_vm_init_libraries();
+}
+if (CleanChunkPoolAsync) {
+Chunk::start_chunk_pool_cleaner_task();
+}
+// initialize compiler(s)
+#if defined(COMPILER1) || defined(COMPILER2) || defined(SHARK) || INCLUDE_JVMCI
+CompileBroker::compilation_init(CHECK_JNI_ERR);
+#endif
+// Pre-initialize some JSR292 core classes to avoid deadlock during class loading.
+// It is done after compilers are initialized, because otherwise compilations of
+// signature polymorphic MH intrinsics can be missed
+// (see SystemDictionary::find_method_handle_intrinsic).
+initialize_jsr292_core_classes(CHECK_JNI_ERR);
+// This will initialize the module system.  Only java.base classes can be
+// loaded until phase 2 completes
+call_initPhase2(CHECK_JNI_ERR);
+// Always call even when there are not JVMTI environments yet, since environments
+// may be attached late and JVMTI must track phases of VM execution
+JvmtiExport::enter_start_phase();
+// Notify JVMTI agents that VM has started (JNI is up) - nop if no agents.
+JvmtiExport::post_vm_start();
+// Final system initialization including security manager and system class loader
+call_initPhase3(CHECK_JNI_ERR);
+// cache the system class loader
+SystemDictionary::compute_java_system_loader(CHECK_(JNI_ERR));
+#if INCLUDE_JVMCI
+if (EnableJVMCI) {
+// Initialize JVMCI eagerly if JVMCIPrintProperties is enabled.
+// The JVMCI Java initialization code will read this flag and
+// do the printing if it's set.
+bool init = JVMCIPrintProperties;
+if (!init) {
+// 8145270: Force initialization of JVMCI runtime otherwise requests for blocking
+// compilations via JVMCI will not actually block until JVMCI is initialized.
+init = UseJVMCICompiler && (!UseInterpreter || !BackgroundCompilation);
+}
+if (init) {
+JVMCIRuntime::force_initialization(CHECK_JNI_ERR);
+}
+}
+#endif
+// Always call even when there are not JVMTI environments yet, since environments
+// may be attached late and JVMTI must track phases of VM execution
+JvmtiExport::enter_live_phase();
+// Notify JVMTI agents that VM initialization is complete - nop if no agents.
+JvmtiExport::post_vm_initialized();
+if (TRACE_START() != JNI_OK) {
+vm_exit_during_initialization("Failed to start tracing backend.");
+}
+#if INCLUDE_MANAGEMENT
+Management::initialize(THREAD);
+if (HAS_PENDING_EXCEPTION) {
+// management agent fails to start possibly due to
+// configuration problem and is responsible for printing
+// stack trace if appropriate. Simply exit VM.
+vm_exit(1);
+}
+#endif // INCLUDE_MANAGEMENT
+if (MemProfiling)                   MemProfiler::engage();
+StatSampler::engage();
+if (CheckJNICalls)                  JniPeriodicChecker::engage();
+BiasedLocking::init();
+#if INCLUDE_RTM_OPT
+RTMLockingCounters::init();
+#endif
+if (JDK_Version::current().post_vm_init_hook_enabled()) {
+call_postVMInitHook(THREAD);
+// The Java side of PostVMInitHook.run must deal with all
+// exceptions and provide means of diagnosis.
+if (HAS_PENDING_EXCEPTION) {
+CLEAR_PENDING_EXCEPTION;
+}
+}
+{
+MutexLocker ml(PeriodicTask_lock);
+// Make sure the WatcherThread can be started by WatcherThread::start()
+// or by dynamic enrollment.
+WatcherThread::make_startable();
+// Start up the WatcherThread if there are any periodic tasks
+// NOTE:  All PeriodicTasks should be registered by now. If they
+//   aren't, late joiners might appear to start slowly (we might
+//   take a while to process their first tick).
+if (PeriodicTask::num_tasks() > 0) {
+WatcherThread::start();
+}
+}
+create_vm_timer.end();
+#ifdef ASSERT
+_vm_complete = true;
+#endif
+if (DumpSharedSpaces) {
+MetaspaceShared::preload_and_dump(CHECK_JNI_ERR);
+ShouldNotReachHere();
+}
+return JNI_OK;
+}
+// type for the Agent_OnLoad and JVM_OnLoad entry points
+extern "C" {
+typedef jint (JNICALL *OnLoadEntry_t)(JavaVM *, char *, void *);
+}
+// Find a command line agent library and return its entry point for
+//         -agentlib:  -agentpath:   -Xrun
+// num_symbol_entries must be passed-in since only the caller knows the number of symbols in the array.
+static OnLoadEntry_t lookup_on_load(AgentLibrary* agent,
+const char *on_load_symbols[],
+size_t num_symbol_entries) {
+OnLoadEntry_t on_load_entry = NULL;
+void *library = NULL;
+if (!agent->valid()) {
+char buffer[JVM_MAXPATHLEN];
+char ebuf[1024] = "";
+const char *name = agent->name();
+const char *msg = "Could not find agent library ";
+// First check to see if agent is statically linked into executable
+if (os::find_builtin_agent(agent, on_load_symbols, num_symbol_entries)) {
+library = agent->os_lib();
+} else if (agent->is_absolute_path()) {
+library = os::dll_load(name, ebuf, sizeof ebuf);
+if (library == NULL) {
+const char *sub_msg = " in absolute path, with error: ";
+size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
+char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
+jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
+// If we can't find the agent, exit.
+vm_exit_during_initialization(buf, NULL);
+FREE_C_HEAP_ARRAY(char, buf);
+}
+} else {
+// Try to load the agent from the standard dll directory
+if (os::dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
+name)) {
+library = os::dll_load(buffer, ebuf, sizeof ebuf);
+}
+if (library == NULL) { // Try the library path directory.
+if (os::dll_build_name(buffer, sizeof(buffer), name)) {
+library = os::dll_load(buffer, ebuf, sizeof ebuf);
+}
+if (library == NULL) {
+const char *sub_msg = " on the library path, with error: ";
+size_t len = strlen(msg) + strlen(name) + strlen(sub_msg) + strlen(ebuf) + 1;
+char *buf = NEW_C_HEAP_ARRAY(char, len, mtThread);
+jio_snprintf(buf, len, "%s%s%s%s", msg, name, sub_msg, ebuf);
+// If we can't find the agent, exit.
+vm_exit_during_initialization(buf, NULL);
+FREE_C_HEAP_ARRAY(char, buf);
+}
+}
+}
+agent->set_os_lib(library);
+agent->set_valid();
+}
+// Find the OnLoad function.
+on_load_entry =
+CAST_TO_FN_PTR(OnLoadEntry_t, os::find_agent_function(agent,
+false,
+on_load_symbols,
+num_symbol_entries));
+return on_load_entry;
+}
+// Find the JVM_OnLoad entry point
+static OnLoadEntry_t lookup_jvm_on_load(AgentLibrary* agent) {
+const char *on_load_symbols[] = JVM_ONLOAD_SYMBOLS;
+return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
+}
+// Find the Agent_OnLoad entry point
+static OnLoadEntry_t lookup_agent_on_load(AgentLibrary* agent) {
+const char *on_load_symbols[] = AGENT_ONLOAD_SYMBOLS;
+return lookup_on_load(agent, on_load_symbols, sizeof(on_load_symbols) / sizeof(char*));
+}
+// For backwards compatibility with -Xrun
+// Convert libraries with no JVM_OnLoad, but which have Agent_OnLoad to be
+// treated like -agentpath:
+// Must be called before agent libraries are created
+void Threads::convert_vm_init_libraries_to_agents() {
+AgentLibrary* agent;
+AgentLibrary* next;
+for (agent = Arguments::libraries(); agent != NULL; agent = next) {
+next = agent->next();  // cache the next agent now as this agent may get moved off this list
+OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
+// If there is an JVM_OnLoad function it will get called later,
+// otherwise see if there is an Agent_OnLoad
+if (on_load_entry == NULL) {
+on_load_entry = lookup_agent_on_load(agent);
+if (on_load_entry != NULL) {
+// switch it to the agent list -- so that Agent_OnLoad will be called,
+// JVM_OnLoad won't be attempted and Agent_OnUnload will
+Arguments::convert_library_to_agent(agent);
+} else {
+vm_exit_during_initialization("Could not find JVM_OnLoad or Agent_OnLoad function in the library", agent->name());
+}
+}
+}
+}
+// Create agents for -agentlib:  -agentpath:  and converted -Xrun
+// Invokes Agent_OnLoad
+// Called very early -- before JavaThreads exist
+void Threads::create_vm_init_agents() {
+extern struct JavaVM_ main_vm;
+AgentLibrary* agent;
+JvmtiExport::enter_onload_phase();
+for (agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
+OnLoadEntry_t  on_load_entry = lookup_agent_on_load(agent);
+if (on_load_entry != NULL) {
+// Invoke the Agent_OnLoad function
+jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
+if (err != JNI_OK) {
+vm_exit_during_initialization("agent library failed to init", agent->name());
+}
+} else {
+vm_exit_during_initialization("Could not find Agent_OnLoad function in the agent library", agent->name());
+}
+}
+JvmtiExport::enter_primordial_phase();
+}
+extern "C" {
+typedef void (JNICALL *Agent_OnUnload_t)(JavaVM *);
+}
+void Threads::shutdown_vm_agents() {
+// Send any Agent_OnUnload notifications
+const char *on_unload_symbols[] = AGENT_ONUNLOAD_SYMBOLS;
+size_t num_symbol_entries = ARRAY_SIZE(on_unload_symbols);
+extern struct JavaVM_ main_vm;
+for (AgentLibrary* agent = Arguments::agents(); agent != NULL; agent = agent->next()) {
+// Find the Agent_OnUnload function.
+Agent_OnUnload_t unload_entry = CAST_TO_FN_PTR(Agent_OnUnload_t,
+os::find_agent_function(agent,
+false,
+on_unload_symbols,
+num_symbol_entries));
+// Invoke the Agent_OnUnload function
+if (unload_entry != NULL) {
+JavaThread* thread = JavaThread::current();
+ThreadToNativeFromVM ttn(thread);
+HandleMark hm(thread);
+(*unload_entry)(&main_vm);
+}
+}
+}
+// Called for after the VM is initialized for -Xrun libraries which have not been converted to agent libraries
+// Invokes JVM_OnLoad
+void Threads::create_vm_init_libraries() {
+extern struct JavaVM_ main_vm;
+AgentLibrary* agent;
+for (agent = Arguments::libraries(); agent != NULL; agent = agent->next()) {
+OnLoadEntry_t on_load_entry = lookup_jvm_on_load(agent);
+if (on_load_entry != NULL) {
+// Invoke the JVM_OnLoad function
+JavaThread* thread = JavaThread::current();
+ThreadToNativeFromVM ttn(thread);
+HandleMark hm(thread);
+jint err = (*on_load_entry)(&main_vm, agent->options(), NULL);
+if (err != JNI_OK) {
+vm_exit_during_initialization("-Xrun library failed to init", agent->name());
+}
+} else {
+vm_exit_during_initialization("Could not find JVM_OnLoad function in -Xrun library", agent->name());
+}
+}
+}
+JavaThread* Threads::find_java_thread_from_java_tid(jlong java_tid) {
+assert(Threads_lock->owned_by_self(), "Must hold Threads_lock");
+JavaThread* java_thread = NULL;
+// Sequential search for now.  Need to do better optimization later.
+for (JavaThread* thread = Threads::first(); thread != NULL; thread = thread->next()) {
+oop tobj = thread->threadObj();
+if (!thread->is_exiting() &&
+tobj != NULL &&
+java_tid == java_lang_Thread::thread_id(tobj)) {
+java_thread = thread;
+break;
+}
+}
+return java_thread;
+}
+// Last thread running calls java.lang.Shutdown.shutdown()
+void JavaThread::invoke_shutdown_hooks() {
+HandleMark hm(this);
+// We could get here with a pending exception, if so clear it now.
+if (this->has_pending_exception()) {
+this->clear_pending_exception();
+}
+EXCEPTION_MARK;
+Klass* shutdown_klass =
+SystemDictionary::resolve_or_null(vmSymbols::java_lang_Shutdown(),
+THREAD);
+if (shutdown_klass != NULL) {
+// SystemDictionary::resolve_or_null will return null if there was
+// an exception.  If we cannot load the Shutdown class, just don't
+// call Shutdown.shutdown() at all.  This will mean the shutdown hooks
+// and finalizers (if runFinalizersOnExit is set) won't be run.
+// Note that if a shutdown hook was registered or runFinalizersOnExit
+// was called, the Shutdown class would have already been loaded
+// (Runtime.addShutdownHook and runFinalizersOnExit will load it).
+JavaValue result(T_VOID);
+JavaCalls::call_static(&result,
+shutdown_klass,
+vmSymbols::shutdown_method_name(),
+vmSymbols::void_method_signature(),
+THREAD);
+}
+CLEAR_PENDING_EXCEPTION;
+}
+// Threads::destroy_vm() is normally called from jni_DestroyJavaVM() when
+// the program falls off the end of main(). Another VM exit path is through
+// vm_exit() when the program calls System.exit() to return a value or when
+// there is a serious error in VM. The two shutdown paths are not exactly
+// the same, but they share Shutdown.shutdown() at Java level and before_exit()
+// and VM_Exit op at VM level.
+//
+// Shutdown sequence:
+//   + Shutdown native memory tracking if it is on
+//   + Wait until we are the last non-daemon thread to execute
+//     <-- every thing is still working at this moment -->
+//   + Call java.lang.Shutdown.shutdown(), which will invoke Java level
+//        shutdown hooks, run finalizers if finalization-on-exit
+//   + Call before_exit(), prepare for VM exit
+//      > run VM level shutdown hooks (they are registered through JVM_OnExit(),
+//        currently the only user of this mechanism is File.deleteOnExit())
+//      > stop StatSampler, watcher thread, CMS threads,
+//        post thread end and vm death events to JVMTI,
+//        stop signal thread
+//   + Call JavaThread::exit(), it will:
+//      > release JNI handle blocks, remove stack guard pages
+//      > remove this thread from Threads list
+//     <-- no more Java code from this thread after this point -->
+//   + Stop VM thread, it will bring the remaining VM to a safepoint and stop
+//     the compiler threads at safepoint
+//     <-- do not use anything that could get blocked by Safepoint -->
+//   + Disable tracing at JNI/JVM barriers
+//   + Set _vm_exited flag for threads that are still running native code
+//   + Delete this thread
+//   + Call exit_globals()
+//      > deletes tty
+//      > deletes PerfMemory resources
+//   + Return to caller
+bool Threads::destroy_vm() {
+JavaThread* thread = JavaThread::current();
+#ifdef ASSERT
+_vm_complete = false;
+#endif
+// Wait until we are the last non-daemon thread to execute
+{ MutexLocker nu(Threads_lock);
+while (Threads::number_of_non_daemon_threads() > 1)
+// This wait should make safepoint checks, wait without a timeout,
+// and wait as a suspend-equivalent condition.
+Threads_lock->wait(!Mutex::_no_safepoint_check_flag, 0,
+Mutex::_as_suspend_equivalent_flag);
+}
+// Hang forever on exit if we are reporting an error.
+if (ShowMessageBoxOnError && VMError::is_error_reported()) {
+os::infinite_sleep();
+}
+os::wait_for_keypress_at_exit();
+// run Java level shutdown hooks
+thread->invoke_shutdown_hooks();
+before_exit(thread);
+thread->exit(true);
+// Stop VM thread.
+{
+// 4945125 The vm thread comes to a safepoint during exit.
+// GC vm_operations can get caught at the safepoint, and the
+// heap is unparseable if they are caught. Grab the Heap_lock
+// to prevent this. The GC vm_operations will not be able to
+// queue until after the vm thread is dead. After this point,
+// we'll never emerge out of the safepoint before the VM exits.
+MutexLocker ml(Heap_lock);
+VMThread::wait_for_vm_thread_exit();
+assert(SafepointSynchronize::is_at_safepoint(), "VM thread should exit at Safepoint");
+VMThread::destroy();
+}
+// clean up ideal graph printers
+#if defined(COMPILER2) && !defined(PRODUCT)
+IdealGraphPrinter::clean_up();
+#endif
+// Now, all Java threads are gone except daemon threads. Daemon threads
+// running Java code or in VM are stopped by the Safepoint. However,
+// daemon threads executing native code are still running.  But they
+// will be stopped at native=>Java/VM barriers. Note that we can't
+// simply kill or suspend them, as it is inherently deadlock-prone.
+VM_Exit::set_vm_exited();
+notify_vm_shutdown();
+delete thread;
+#if INCLUDE_JVMCI
+if (JVMCICounterSize > 0) {
+FREE_C_HEAP_ARRAY(jlong, JavaThread::_jvmci_old_thread_counters);
+}
+#endif
+// exit_globals() will delete tty
+exit_globals();
+LogConfiguration::finalize();
+return true;
+}
+jboolean Threads::is_supported_jni_version_including_1_1(jint version) {
+if (version == JNI_VERSION_1_1) return JNI_TRUE;
+return is_supported_jni_version(version);
+}
+jboolean Threads::is_supported_jni_version(jint version) {
+if (version == JNI_VERSION_1_2) return JNI_TRUE;
+if (version == JNI_VERSION_1_4) return JNI_TRUE;
+if (version == JNI_VERSION_1_6) return JNI_TRUE;
+if (version == JNI_VERSION_1_8) return JNI_TRUE;
+if (version == JNI_VERSION_9) return JNI_TRUE;
+return JNI_FALSE;
+}
+void Threads::add(JavaThread* p, bool force_daemon) {
+// The threads lock must be owned at this point
+assert_locked_or_safepoint(Threads_lock);
+// See the comment for this method in thread.hpp for its purpose and
+// why it is called here.
+p->initialize_queues();
+p->set_next(_thread_list);
+_thread_list = p;
+_number_of_threads++;
+oop threadObj = p->threadObj();
+bool daemon = true;
+// Bootstrapping problem: threadObj can be null for initial
+// JavaThread (or for threads attached via JNI)
+if ((!force_daemon) && (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj))) {
+_number_of_non_daemon_threads++;
+daemon = false;
+}
+ThreadService::add_thread(p, daemon);
+// Possible GC point.
+Events::log(p, "Thread added: " INTPTR_FORMAT, p2i(p));
+}
+void Threads::remove(JavaThread* p) {
+// Reclaim the objectmonitors from the omInUseList and omFreeList of the moribund thread.
+ObjectSynchronizer::omFlush(p);
+// Extra scope needed for Thread_lock, so we can check
+// that we do not remove thread without safepoint code notice
+{ MutexLocker ml(Threads_lock);
+assert(includes(p), "p must be present");
+JavaThread* current = _thread_list;
+JavaThread* prev    = NULL;
+while (current != p) {
+prev    = current;
+current = current->next();
+}
+if (prev) {
+prev->set_next(current->next());
+} else {
+_thread_list = p->next();
+}
+_number_of_threads--;
+oop threadObj = p->threadObj();
+bool daemon = true;
+if (threadObj == NULL || !java_lang_Thread::is_daemon(threadObj)) {
+_number_of_non_daemon_threads--;
+daemon = false;
+// Only one thread left, do a notify on the Threads_lock so a thread waiting
+// on destroy_vm will wake up.
+if (number_of_non_daemon_threads() == 1) {
+Threads_lock->notify_all();
+}
+}
+ThreadService::remove_thread(p, daemon);
+// Make sure that safepoint code disregard this thread. This is needed since
+// the thread might mess around with locks after this point. This can cause it
+// to do callbacks into the safepoint code. However, the safepoint code is not aware
+// of this thread since it is removed from the queue.
+p->set_terminated_value();
+} // unlock Threads_lock
+// Since Events::log uses a lock, we grab it outside the Threads_lock
+Events::log(p, "Thread exited: " INTPTR_FORMAT, p2i(p));
+}
+// Threads_lock must be held when this is called (or must be called during a safepoint)
+bool Threads::includes(JavaThread* p) {
+assert(Threads_lock->is_locked(), "sanity check");
+ALL_JAVA_THREADS(q) {
+if (q == p) {
+return true;
+}
+}
+return false;
+}
+// Operations on the Threads list for GC.  These are not explicitly locked,
+// but the garbage collector must provide a safe context for them to run.
+// In particular, these things should never be called when the Threads_lock
+// is held by some other thread. (Note: the Safepoint abstraction also
+// uses the Threads_lock to guarantee this property. It also makes sure that
+// all threads gets blocked when exiting or starting).
+void Threads::oops_do(OopClosure* f, CodeBlobClosure* cf) {
+ALL_JAVA_THREADS(p) {
+p->oops_do(f, cf);
+}
+VMThread::vm_thread()->oops_do(f, cf);
+}
+void Threads::change_thread_claim_parity() {
+// Set the new claim parity.
+assert(_thread_claim_parity >= 0 && _thread_claim_parity <= 2,
+"Not in range.");
+_thread_claim_parity++;
+if (_thread_claim_parity == 3) _thread_claim_parity = 1;
+assert(_thread_claim_parity >= 1 && _thread_claim_parity <= 2,
+"Not in range.");
+}
+#ifdef ASSERT
+void Threads::assert_all_threads_claimed() {
+ALL_JAVA_THREADS(p) {
+const int thread_parity = p->oops_do_parity();
+assert((thread_parity == _thread_claim_parity),
+"Thread " PTR_FORMAT " has incorrect parity %d != %d", p2i(p), thread_parity, _thread_claim_parity);
+}
+VMThread* vmt = VMThread::vm_thread();
+const int thread_parity = vmt->oops_do_parity();
+assert((thread_parity == _thread_claim_parity),
+"VMThread " PTR_FORMAT " has incorrect parity %d != %d", p2i(vmt), thread_parity, _thread_claim_parity);
+}
+#endif // ASSERT
+void Threads::possibly_parallel_oops_do(bool is_par, OopClosure* f, CodeBlobClosure* cf) {
+int cp = Threads::thread_claim_parity();
+ALL_JAVA_THREADS(p) {
+if (p->claim_oops_do(is_par, cp)) {
+p->oops_do(f, cf);
+}
+}
+VMThread* vmt = VMThread::vm_thread();
+if (vmt->claim_oops_do(is_par, cp)) {
+vmt->oops_do(f, cf);
+}
+}
+#if INCLUDE_ALL_GCS
+// Used by ParallelScavenge
+void Threads::create_thread_roots_tasks(GCTaskQueue* q) {
+ALL_JAVA_THREADS(p) {
+q->enqueue(new ThreadRootsTask(p));
+}
+q->enqueue(new ThreadRootsTask(VMThread::vm_thread()));
+}
+// Used by Parallel Old
+void Threads::create_thread_roots_marking_tasks(GCTaskQueue* q) {
+ALL_JAVA_THREADS(p) {
+q->enqueue(new ThreadRootsMarkingTask(p));
+}
+q->enqueue(new ThreadRootsMarkingTask(VMThread::vm_thread()));
+}
+#endif // INCLUDE_ALL_GCS
+void Threads::nmethods_do(CodeBlobClosure* cf) {
+ALL_JAVA_THREADS(p) {
+// This is used by the code cache sweeper to mark nmethods that are active
+// on the stack of a Java thread. Ignore the sweeper thread itself to avoid
+// marking CodeCacheSweeperThread::_scanned_compiled_method as active.
+if(!p->is_Code_cache_sweeper_thread()) {
+p->nmethods_do(cf);
+}
+}
+}
+void Threads::metadata_do(void f(Metadata*)) {
+ALL_JAVA_THREADS(p) {
+p->metadata_do(f);
+}
+}
+class ThreadHandlesClosure : public ThreadClosure {
+void (*_f)(Metadata*);
+public:
+ThreadHandlesClosure(void f(Metadata*)) : _f(f) {}
+virtual void do_thread(Thread* thread) {
+thread->metadata_handles_do(_f);
+}
+};
+void Threads::metadata_handles_do(void f(Metadata*)) {
+// Only walk the Handles in Thread.
+ThreadHandlesClosure handles_closure(f);
+threads_do(&handles_closure);
+}
+void Threads::deoptimized_wrt_marked_nmethods() {
+ALL_JAVA_THREADS(p) {
+p->deoptimized_wrt_marked_nmethods();
+}
+}
+// Get count Java threads that are waiting to enter the specified monitor.
+GrowableArray<JavaThread*>* Threads::get_pending_threads(int count,
+address monitor,
+bool doLock) {
+assert(doLock || SafepointSynchronize::is_at_safepoint(),
+"must grab Threads_lock or be at safepoint");
+GrowableArray<JavaThread*>* result = new GrowableArray<JavaThread*>(count);
+int i = 0;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(p) {
+if (!p->can_call_java()) continue;
+address pending = (address)p->current_pending_monitor();
+if (pending == monitor) {             // found a match
+if (i < count) result->append(p);   // save the first count matches
+i++;
+}
+}
+}
+return result;
+}
+JavaThread *Threads::owning_thread_from_monitor_owner(address owner,
+bool doLock) {
+assert(doLock ||
+Threads_lock->owned_by_self() ||
+SafepointSynchronize::is_at_safepoint(),
+"must grab Threads_lock or be at safepoint");
+// NULL owner means not locked so we can skip the search
+if (owner == NULL) return NULL;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(p) {
+// first, see if owner is the address of a Java thread
+if (owner == (address)p) return p;
+}
+}
+// Cannot assert on lack of success here since this function may be
+// used by code that is trying to report useful problem information
+// like deadlock detection.
+if (UseHeavyMonitors) return NULL;
+// If we didn't find a matching Java thread and we didn't force use of
+// heavyweight monitors, then the owner is the stack address of the
+// Lock Word in the owning Java thread's stack.
+//
+JavaThread* the_owner = NULL;
+{
+MutexLockerEx ml(doLock ? Threads_lock : NULL);
+ALL_JAVA_THREADS(q) {
+if (q->is_lock_owned(owner)) {
+the_owner = q;
+break;
+}
+}
+}
+// cannot assert on lack of success here; see above comment
+return the_owner;
+}
+// Threads::print_on() is called at safepoint by VM_PrintThreads operation.
+void Threads::print_on(outputStream* st, bool print_stacks,
+bool internal_format, bool print_concurrent_locks) {
+char buf[32];
+st->print_raw_cr(os::local_time_string(buf, sizeof(buf)));
+st->print_cr("Full thread dump %s (%s %s):",
+Abstract_VM_Version::vm_name(),
+Abstract_VM_Version::vm_release(),
+Abstract_VM_Version::vm_info_string());
+st->cr();
+#if INCLUDE_SERVICES
+// Dump concurrent locks
+ConcurrentLocksDump concurrent_locks;
+if (print_concurrent_locks) {
+concurrent_locks.dump_at_safepoint();
+}
+#endif // INCLUDE_SERVICES
+ALL_JAVA_THREADS(p) {
+ResourceMark rm;
+p->print_on(st);
+if (print_stacks) {
+if (internal_format) {
+p->trace_stack();
+} else {
+p->print_stack_on(st);
+}
+}
+st->cr();
+#if INCLUDE_SERVICES
+if (print_concurrent_locks) {
+concurrent_locks.print_locks_on(p, st);
+}
+#endif // INCLUDE_SERVICES
+}
+VMThread::vm_thread()->print_on(st);
+st->cr();
+Universe::heap()->print_gc_threads_on(st);
+WatcherThread* wt = WatcherThread::watcher_thread();
+if (wt != NULL) {
+wt->print_on(st);
+st->cr();
+}
+st->flush();
+}
+void Threads::print_on_error(Thread* this_thread, outputStream* st, Thread* current, char* buf,
+int buflen, bool* found_current) {
+if (this_thread != NULL) {
+bool is_current = (current == this_thread);
+*found_current = *found_current || is_current;
+st->print("%s", is_current ? "=>" : "  ");
+st->print(PTR_FORMAT, p2i(this_thread));
+st->print(" ");
+this_thread->print_on_error(st, buf, buflen);
+st->cr();
+}
+}
+class PrintOnErrorClosure : public ThreadClosure {
+outputStream* _st;
+Thread* _current;
+char* _buf;
+int _buflen;
+bool* _found_current;
+public:
+PrintOnErrorClosure(outputStream* st, Thread* current, char* buf,
+int buflen, bool* found_current) :
+_st(st), _current(current), _buf(buf), _buflen(buflen), _found_current(found_current) {}
+virtual void do_thread(Thread* thread) {
+Threads::print_on_error(thread, _st, _current, _buf, _buflen, _found_current);
+}
+};
+// Threads::print_on_error() is called by fatal error handler. It's possible
+// that VM is not at safepoint and/or current thread is inside signal handler.
+// Don't print stack trace, as the stack may not be walkable. Don't allocate
+// memory (even in resource area), it might deadlock the error handler.
+void Threads::print_on_error(outputStream* st, Thread* current, char* buf,
+int buflen) {
+bool found_current = false;
+st->print_cr("Java Threads: ( => current thread )");
+ALL_JAVA_THREADS(thread) {
+print_on_error(thread, st, current, buf, buflen, &found_current);
+}
+st->cr();
+st->print_cr("Other Threads:");
+print_on_error(VMThread::vm_thread(), st, current, buf, buflen, &found_current);
+print_on_error(WatcherThread::watcher_thread(), st, current, buf, buflen, &found_current);
+PrintOnErrorClosure print_closure(st, current, buf, buflen, &found_current);
+Universe::heap()->gc_threads_do(&print_closure);
+if (!found_current) {
+st->cr();
+st->print("=>" PTR_FORMAT " (exited) ", p2i(current));
+current->print_on_error(st, buf, buflen);
+st->cr();
+}
+st->cr();
+st->print_cr("Threads with active compile tasks:");
+print_threads_compiling(st, buf, buflen);
+}
+void Threads::print_threads_compiling(outputStream* st, char* buf, int buflen) {
+ALL_JAVA_THREADS(thread) {
+if (thread->is_Compiler_thread()) {
+CompilerThread* ct = (CompilerThread*) thread;
+if (ct->task() != NULL) {
+thread->print_name_on_error(st, buf, buflen);
+ct->task()->print(st, NULL, true, true);
+}
+}
+}
+}
+// Internal SpinLock and Mutex
+// Based on ParkEvent
+// Ad-hoc mutual exclusion primitives: SpinLock and Mux
+//
+// We employ SpinLocks _only for low-contention, fixed-length
+// short-duration critical sections where we're concerned
+// about native mutex_t or HotSpot Mutex:: latency.
+// The mux construct provides a spin-then-block mutual exclusion
+// mechanism.
+//
+// Testing has shown that contention on the ListLock guarding gFreeList
+// is common.  If we implement ListLock as a simple SpinLock it's common
+// for the JVM to devolve to yielding with little progress.  This is true
+// despite the fact that the critical sections protected by ListLock are
+// extremely short.
+//
+// TODO-FIXME: ListLock should be of type SpinLock.
+// We should make this a 1st-class type, integrated into the lock
+// hierarchy as leaf-locks.  Critically, the SpinLock structure
+// should have sufficient padding to avoid false-sharing and excessive
+// cache-coherency traffic.
+typedef volatile int SpinLockT;
+void Thread::SpinAcquire(volatile int * adr, const char * LockName) {
+if (Atomic::cmpxchg (1, adr, 0) == 0) {
+return;   // normal fast-path return
+}
+// Slow-path : We've encountered contention -- Spin/Yield/Block strategy.
+TEVENT(SpinAcquire - ctx);
+int ctr = 0;
+int Yields = 0;
+for (;;) {
+while (*adr != 0) {
+++ctr;
+if ((ctr & 0xFFF) == 0 || !os::is_MP()) {
+if (Yields > 5) {
+os::naked_short_sleep(1);
+} else {
+os::naked_yield();
+++Yields;
+}
+} else {
+SpinPause();
+}
+}
+if (Atomic::cmpxchg(1, adr, 0) == 0) return;
+}
+}
+void Thread::SpinRelease(volatile int * adr) {
+assert(*adr != 0, "invariant");
+OrderAccess::fence();      // guarantee at least release consistency.
+// Roach-motel semantics.
+// It's safe if subsequent LDs and STs float "up" into the critical section,
+// but prior LDs and STs within the critical section can't be allowed
+// to reorder or float past the ST that releases the lock.
+// Loads and stores in the critical section - which appear in program
+// order before the store that releases the lock - must also appear
+// before the store that releases the lock in memory visibility order.
+// Conceptually we need a #loadstore|#storestore "release" MEMBAR before
+// the ST of 0 into the lock-word which releases the lock, so fence
+// more than covers this on all platforms.
+*adr = 0;
+}
+// muxAcquire and muxRelease:
+//
+// *  muxAcquire and muxRelease support a single-word lock-word construct.
+//    The LSB of the word is set IFF the lock is held.
+//    The remainder of the word points to the head of a singly-linked list
+//    of threads blocked on the lock.
+//
+// *  The current implementation of muxAcquire-muxRelease uses its own
+//    dedicated Thread._MuxEvent instance.  If we're interested in
+//    minimizing the peak number of extant ParkEvent instances then
+//    we could eliminate _MuxEvent and "borrow" _ParkEvent as long
+//    as certain invariants were satisfied.  Specifically, care would need
+//    to be taken with regards to consuming unpark() "permits".
+//    A safe rule of thumb is that a thread would never call muxAcquire()
+//    if it's enqueued (cxq, EntryList, WaitList, etc) and will subsequently
+//    park().  Otherwise the _ParkEvent park() operation in muxAcquire() could
+//    consume an unpark() permit intended for monitorenter, for instance.
+//    One way around this would be to widen the restricted-range semaphore
+//    implemented in park().  Another alternative would be to provide
+//    multiple instances of the PlatformEvent() for each thread.  One
+//    instance would be dedicated to muxAcquire-muxRelease, for instance.
+//
+// *  Usage:
+//    -- Only as leaf locks
+//    -- for short-term locking only as muxAcquire does not perform
+//       thread state transitions.
+//
+// Alternatives:
+// *  We could implement muxAcquire and muxRelease with MCS or CLH locks
+//    but with parking or spin-then-park instead of pure spinning.
+// *  Use Taura-Oyama-Yonenzawa locks.
+// *  It's possible to construct a 1-0 lock if we encode the lockword as
+//    (List,LockByte).  Acquire will CAS the full lockword while Release
+//    will STB 0 into the LockByte.  The 1-0 scheme admits stranding, so
+//    acquiring threads use timers (ParkTimed) to detect and recover from
+//    the stranding window.  Thread/Node structures must be aligned on 256-byte
+//    boundaries by using placement-new.
+// *  Augment MCS with advisory back-link fields maintained with CAS().
+//    Pictorially:  LockWord -> T1 <-> T2 <-> T3 <-> ... <-> Tn <-> Owner.
+//    The validity of the backlinks must be ratified before we trust the value.
+//    If the backlinks are invalid the exiting thread must back-track through the
+//    the forward links, which are always trustworthy.
+// *  Add a successor indication.  The LockWord is currently encoded as
+//    (List, LOCKBIT:1).  We could also add a SUCCBIT or an explicit _succ variable
+//    to provide the usual futile-wakeup optimization.
+//    See RTStt for details.
+// *  Consider schedctl.sc_nopreempt to cover the critical section.
+//
+typedef volatile intptr_t MutexT;      // Mux Lock-word
+enum MuxBits { LOCKBIT = 1 };
+void Thread::muxAcquire(volatile intptr_t * Lock, const char * LockName) {
+intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
+if (w == 0) return;
+if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+return;
+}
+TEVENT(muxAcquire - Contention);
+ParkEvent * const Self = Thread::current()->_MuxEvent;
+assert((intptr_t(Self) & LOCKBIT) == 0, "invariant");
+for (;;) {
+int its = (os::is_MP() ? 100 : 0) + 1;
+// Optional spin phase: spin-then-park strategy
+while (--its >= 0) {
+w = *Lock;
+if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+return;
+}
+}
+Self->reset();
+Self->OnList = intptr_t(Lock);
+// The following fence() isn't _strictly necessary as the subsequent
+// CAS() both serializes execution and ratifies the fetched *Lock value.
+OrderAccess::fence();
+for (;;) {
+w = *Lock;
+if ((w & LOCKBIT) == 0) {
+if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+Self->OnList = 0;   // hygiene - allows stronger asserts
+return;
+}
+continue;      // Interference -- *Lock changed -- Just retry
+}
+assert(w & LOCKBIT, "invariant");
+Self->ListNext = (ParkEvent *) (w & ~LOCKBIT);
+if (Atomic::cmpxchg_ptr(intptr_t(Self)|LOCKBIT, Lock, w) == w) break;
+}
+while (Self->OnList != 0) {
+Self->park();
+}
+}
+}
+void Thread::muxAcquireW(volatile intptr_t * Lock, ParkEvent * ev) {
+intptr_t w = Atomic::cmpxchg_ptr(LOCKBIT, Lock, 0);
+if (w == 0) return;
+if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+return;
+}
+TEVENT(muxAcquire - Contention);
+ParkEvent * ReleaseAfter = NULL;
+if (ev == NULL) {
+ev = ReleaseAfter = ParkEvent::Allocate(NULL);
+}
+assert((intptr_t(ev) & LOCKBIT) == 0, "invariant");
+for (;;) {
+guarantee(ev->OnList == 0, "invariant");
+int its = (os::is_MP() ? 100 : 0) + 1;
+// Optional spin phase: spin-then-park strategy
+while (--its >= 0) {
+w = *Lock;
+if ((w & LOCKBIT) == 0 && Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+if (ReleaseAfter != NULL) {
+ParkEvent::Release(ReleaseAfter);
+}
+return;
+}
+}
+ev->reset();
+ev->OnList = intptr_t(Lock);
+// The following fence() isn't _strictly necessary as the subsequent
+// CAS() both serializes execution and ratifies the fetched *Lock value.
+OrderAccess::fence();
+for (;;) {
+w = *Lock;
+if ((w & LOCKBIT) == 0) {
+if (Atomic::cmpxchg_ptr (w|LOCKBIT, Lock, w) == w) {
+ev->OnList = 0;
+// We call ::Release while holding the outer lock, thus
+// artificially lengthening the critical section.
+// Consider deferring the ::Release() until the subsequent unlock(),
+// after we've dropped the outer lock.
+if (ReleaseAfter != NULL) {
+ParkEvent::Release(ReleaseAfter);
+}
+return;
+}
+continue;      // Interference -- *Lock changed -- Just retry
+}
+assert(w & LOCKBIT, "invariant");
+ev->ListNext = (ParkEvent *) (w & ~LOCKBIT);
+if (Atomic::cmpxchg_ptr(intptr_t(ev)|LOCKBIT, Lock, w) == w) break;
+}
+while (ev->OnList != 0) {
+ev->park();
+}
+}
+}
+// Release() must extract a successor from the list and then wake that thread.
+// It can "pop" the front of the list or use a detach-modify-reattach (DMR) scheme
+// similar to that used by ParkEvent::Allocate() and ::Release().  DMR-based
+// Release() would :
+// (A) CAS() or swap() null to *Lock, releasing the lock and detaching the list.
+// (B) Extract a successor from the private list "in-hand"
+// (C) attempt to CAS() the residual back into *Lock over null.
+//     If there were any newly arrived threads and the CAS() would fail.
+//     In that case Release() would detach the RATs, re-merge the list in-hand
+//     with the RATs and repeat as needed.  Alternately, Release() might
+//     detach and extract a successor, but then pass the residual list to the wakee.
+//     The wakee would be responsible for reattaching and remerging before it
+//     competed for the lock.
+//
+// Both "pop" and DMR are immune from ABA corruption -- there can be
+// multiple concurrent pushers, but only one popper or detacher.
+// This implementation pops from the head of the list.  This is unfair,
+// but tends to provide excellent throughput as hot threads remain hot.
+// (We wake recently run threads first).
+//
+// All paths through muxRelease() will execute a CAS.
+// Release consistency -- We depend on the CAS in muxRelease() to provide full
+// bidirectional fence/MEMBAR semantics, ensuring that all prior memory operations
+// executed within the critical section are complete and globally visible before the
+// store (CAS) to the lock-word that releases the lock becomes globally visible.
+void Thread::muxRelease(volatile intptr_t * Lock)  {
+for (;;) {
+const intptr_t w = Atomic::cmpxchg_ptr(0, Lock, LOCKBIT);
+assert(w & LOCKBIT, "invariant");
+if (w == LOCKBIT) return;
+ParkEvent * const List = (ParkEvent *) (w & ~LOCKBIT);
+assert(List != NULL, "invariant");
+assert(List->OnList == intptr_t(Lock), "invariant");
+ParkEvent * const nxt = List->ListNext;
+guarantee((intptr_t(nxt) & LOCKBIT) == 0, "invariant");
+// The following CAS() releases the lock and pops the head element.
+// The CAS() also ratifies the previously fetched lock-word value.
+if (Atomic::cmpxchg_ptr (intptr_t(nxt), Lock, w) != w) {
+continue;
+}
+List->OnList = 0;
+OrderAccess::fence();
+List->unpark();
+return;
+}
+}
+void Threads::verify() {
+ALL_JAVA_THREADS(p) {
+p->verify();
+}
+VMThread* thread = VMThread::vm_thread();
+if (thread != NULL) thread->verify();
+}

changeset 47216	71c04702a3d5
parent 47106	bed18a111b90
child 47600	5c8607bb3d2d