blob: 085bd982c377d6b4e303e51725c31e54827831b0 [file] [log] [blame]
* Copyright (C) 2011 The Android Open Source Project
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include <atomic>
#include <bitset>
#include <deque>
#include <iosfwd>
#include <list>
#include <memory>
#include <string>
#include "base/atomic.h"
#include "base/enums.h"
#include "base/locks.h"
#include "base/macros.h"
#include "base/safe_map.h"
#include "base/value_object.h"
#include "entrypoints/jni/jni_entrypoints.h"
#include "entrypoints/quick/quick_entrypoints.h"
#include "handle_scope.h"
#include "interpreter/interpreter_cache.h"
#include "jvalue.h"
#include "managed_stack.h"
#include "offsets.h"
#include "read_barrier_config.h"
#include "runtime_globals.h"
#include "runtime_stats.h"
#include "suspend_reason.h"
#include "thread_state.h"
class BacktraceMap;
namespace art {
namespace gc {
namespace accounting {
template<class T> class AtomicStack;
} // namespace accounting
namespace collector {
class SemiSpace;
} // namespace collector
} // namespace gc
namespace instrumentation {
struct InstrumentationStackFrame;
} // namespace instrumentation
namespace mirror {
class Array;
class Class;
class ClassLoader;
class Object;
template<class T> class ObjectArray;
template<class T> class PrimitiveArray;
typedef PrimitiveArray<int32_t> IntArray;
class StackTraceElement;
class String;
class Throwable;
} // namespace mirror
namespace verifier {
class MethodVerifier;
class VerifierDeps;
} // namespace verifier
class ArtMethod;
class BaseMutex;
class ClassLinker;
class Closure;
class Context;
struct DebugInvokeReq;
class DeoptimizationContextRecord;
class DexFile;
class FrameIdToShadowFrame;
class JavaVMExt;
class JNIEnvExt;
class Monitor;
class RootVisitor;
class ScopedObjectAccessAlreadyRunnable;
class ShadowFrame;
class SingleStepControl;
class StackedShadowFrameRecord;
class Thread;
class ThreadList;
enum VisitRootFlags : uint8_t;
// A piece of data that can be held in the CustomTls. The destructor will be called during thread
// shutdown. The thread the destructor is called on is not necessarily the same thread it was stored
// on.
class TLSData {
virtual ~TLSData() {}
// Thread priorities. These must match the Thread.MIN_PRIORITY,
// Thread.NORM_PRIORITY, and Thread.MAX_PRIORITY constants.
enum ThreadPriority {
kMinThreadPriority = 1,
kNormThreadPriority = 5,
kMaxThreadPriority = 10,
enum ThreadFlag {
kSuspendRequest = 1, // If set implies that suspend_count_ > 0 and the Thread should enter the
// safepoint handler.
kCheckpointRequest = 2, // Request that the thread do some checkpoint work and then continue.
kEmptyCheckpointRequest = 4, // Request that the thread do empty checkpoint and then continue.
kActiveSuspendBarrier = 8, // Register that at least 1 suspend barrier needs to be passed.
enum class StackedShadowFrameType {
// The type of method that triggers deoptimization. It contains info on whether
// the deoptimized method should advance dex_pc.
enum class DeoptimizationMethodType {
kKeepDexPc, // dex pc is required to be kept upon deoptimization.
kDefault // dex pc may or may not advance depending on other conditions.
// This should match RosAlloc::kNumThreadLocalSizeBrackets.
static constexpr size_t kNumRosAllocThreadLocalSizeBracketsInThread = 16;
// Thread's stack layout for implicit stack overflow checks:
// +---------------------+ <- highest address of stack memory
// | |
// . . <- SP
// | |
// | |
// +---------------------+ <- stack_end
// | |
// | Gap |
// | |
// +---------------------+ <- stack_begin
// | |
// | Protected region |
// | |
// +---------------------+ <- lowest address of stack memory
// The stack always grows down in memory. At the lowest address is a region of memory
// that is set mprotect(PROT_NONE). Any attempt to read/write to this region will
// result in a segmentation fault signal. At any point, the thread's SP will be somewhere
// between the stack_end and the highest address in stack memory. An implicit stack
// overflow check is a read of memory at a certain offset below the current SP (4K typically).
// If the thread's SP is below the stack_end address this will be a read into the protected
// region. If the SP is above the stack_end address, the thread is guaranteed to have
// at least 4K of space. Because stack overflow checks are only performed in generated code,
// if the thread makes a call out to a native function (through JNI), that native function
// might only have 4K of memory (if the SP is adjacent to stack_end).
class Thread {
static const size_t kStackOverflowImplicitCheckSize;
static constexpr bool kVerifyStack = kIsDebugBuild;
// Creates a new native thread corresponding to the given managed peer.
// Used to implement Thread.start.
static void CreateNativeThread(JNIEnv* env, jobject peer, size_t stack_size, bool daemon);
// Attaches the calling native thread to the runtime, returning the new native peer.
// Used to implement JNI AttachCurrentThread and AttachCurrentThreadAsDaemon calls.
static Thread* Attach(const char* thread_name, bool as_daemon, jobject thread_group,
bool create_peer);
// Attaches the calling native thread to the runtime, returning the new native peer.
static Thread* Attach(const char* thread_name, bool as_daemon, jobject thread_peer);
// Reset internal state of child thread after fork.
void InitAfterFork();
// Get the currently executing thread, frequently referred to as 'self'. This call has reasonably
// high cost and so we favor passing self around when possible.
// TODO: mark as PURE so the compiler may coalesce and remove?
static Thread* Current();
// On a runnable thread, check for pending thread suspension request and handle if pending.
void AllowThreadSuspension() REQUIRES_SHARED(Locks::mutator_lock_);
// Process pending thread suspension request and handle if pending.
void CheckSuspend() REQUIRES_SHARED(Locks::mutator_lock_);
// Process a pending empty checkpoint if pending.
void CheckEmptyCheckpointFromWeakRefAccess(BaseMutex* cond_var_mutex);
void CheckEmptyCheckpointFromMutex();
static Thread* FromManagedThread(const ScopedObjectAccessAlreadyRunnable& ts,
ObjPtr<mirror::Object> thread_peer)
REQUIRES(Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_)
static Thread* FromManagedThread(const ScopedObjectAccessAlreadyRunnable& ts, jobject thread)
REQUIRES(Locks::thread_list_lock_, !Locks::thread_suspend_count_lock_)
// Translates 172 to pAllocArrayFromCode and so on.
template<PointerSize size_of_pointers>
static void DumpThreadOffset(std::ostream& os, uint32_t offset);
// Dumps a one-line summary of thread state (used for operator<<).
void ShortDump(std::ostream& os) const;
// Dumps the detailed thread state and the thread stack (used for SIGQUIT).
void Dump(std::ostream& os,
bool dump_native_stack = true,
BacktraceMap* backtrace_map = nullptr,
bool force_dump_stack = false) const
void DumpJavaStack(std::ostream& os,
bool check_suspended = true,
bool dump_locks = true) const
// Dumps the SIGQUIT per-thread header. 'thread' can be null for a non-attached thread, in which
// case we use 'tid' to identify the thread, and we'll include as much information as we can.
static void DumpState(std::ostream& os, const Thread* thread, pid_t tid)
ThreadState GetState() const {
DCHECK_GE(tls32_.state_and_flags.as_struct.state, kTerminated);
DCHECK_LE(tls32_.state_and_flags.as_struct.state, kSuspended);
return static_cast<ThreadState>(tls32_.state_and_flags.as_struct.state);
ThreadState SetState(ThreadState new_state);
int GetSuspendCount() const REQUIRES(Locks::thread_suspend_count_lock_) {
return tls32_.suspend_count;
int GetUserCodeSuspendCount() const REQUIRES(Locks::thread_suspend_count_lock_,
Locks::user_code_suspension_lock_) {
return tls32_.user_code_suspend_count;
int GetDebugSuspendCount() const REQUIRES(Locks::thread_suspend_count_lock_) {
return tls32_.debug_suspend_count;
bool IsSuspended() const {
union StateAndFlags state_and_flags;
state_and_flags.as_int = tls32_.state_and_flags.as_int;
return state_and_flags.as_struct.state != kRunnable &&
(state_and_flags.as_struct.flags & kSuspendRequest) != 0;
// If delta > 0 and (this != self or suspend_barrier is not null), this function may temporarily
// release thread_suspend_count_lock_ internally.
bool ModifySuspendCount(Thread* self,
int delta,
AtomicInteger* suspend_barrier,
SuspendReason reason)
// Requests a checkpoint closure to run on another thread. The closure will be run when the thread
// gets suspended. This will return true if the closure was added and will (eventually) be
// executed. It returns false otherwise.
// Since multiple closures can be queued and some closures can delay other threads from running no
// closure should attempt to suspend another thread while running.
// TODO We should add some debug option that verifies this.
bool RequestCheckpoint(Closure* function)
// RequestSynchronousCheckpoint releases the thread_list_lock_ as a part of its execution. This is
// due to the fact that Thread::Current() needs to go to sleep to allow the targeted thread to
// execute the checkpoint for us if it is Runnable. The suspend_state is the state that the thread
// will go into while it is awaiting the checkpoint to be run.
// NB Passing ThreadState::kRunnable may cause the current thread to wait in a condition variable
// while holding the mutator_lock_. Callers should ensure that this will not cause any problems
// for the closure or the rest of the system.
// NB Since multiple closures can be queued and some closures can delay other threads from running
// no closure should attempt to suspend another thread while running.
bool RequestSynchronousCheckpoint(Closure* function,
ThreadState suspend_state = ThreadState::kWaiting)
bool RequestEmptyCheckpoint()
void SetFlipFunction(Closure* function);
Closure* GetFlipFunction();
gc::accounting::AtomicStack<mirror::Object>* GetThreadLocalMarkStack() {
return tlsPtr_.thread_local_mark_stack;
void SetThreadLocalMarkStack(gc::accounting::AtomicStack<mirror::Object>* stack) {
tlsPtr_.thread_local_mark_stack = stack;
// Called when thread detected that the thread_suspend_count_ was non-zero. Gives up share of
// mutator_lock_ and waits until it is resumed and thread_suspend_count_ is zero.
void FullSuspendCheck()
// Transition from non-runnable to runnable state acquiring share on mutator_lock_.
ALWAYS_INLINE ThreadState TransitionFromSuspendedToRunnable()
// Transition from runnable into a state where mutator privileges are denied. Releases share of
// mutator lock.
ALWAYS_INLINE void TransitionFromRunnableToSuspended(ThreadState new_state)
REQUIRES(!Locks::thread_suspend_count_lock_, !Roles::uninterruptible_)
// Once called thread suspension will cause an assertion failure.
const char* StartAssertNoThreadSuspension(const char* cause) ACQUIRE(Roles::uninterruptible_) {
Roles::uninterruptible_.Acquire(); // No-op.
if (kIsDebugBuild) {
CHECK(cause != nullptr);
const char* previous_cause = tlsPtr_.last_no_thread_suspension_cause;
tlsPtr_.last_no_thread_suspension_cause = cause;
return previous_cause;
} else {
return nullptr;
// End region where no thread suspension is expected.
void EndAssertNoThreadSuspension(const char* old_cause) RELEASE(Roles::uninterruptible_) {
if (kIsDebugBuild) {
CHECK(old_cause != nullptr || tls32_.no_thread_suspension == 1);
CHECK_GT(tls32_.no_thread_suspension, 0U);
tlsPtr_.last_no_thread_suspension_cause = old_cause;
Roles::uninterruptible_.Release(); // No-op.
void AssertThreadSuspensionIsAllowable(bool check_locks = true) const;
// Return true if thread suspension is allowable.
bool IsThreadSuspensionAllowable() const;
bool IsDaemon() const {
return tls32_.daemon;
size_t NumberOfHeldMutexes() const;
bool HoldsLock(ObjPtr<mirror::Object> object) const REQUIRES_SHARED(Locks::mutator_lock_);
* Changes the priority of this thread to match that of the java.lang.Thread object.
* We map a priority value from 1-10 to Linux "nice" values, where lower
* numbers indicate higher priority.
void SetNativePriority(int newPriority);
* Returns the thread priority for the current thread by querying the system.
* This is useful when attaching a thread through JNI.
* Returns a value from 1 to 10 (compatible with java.lang.Thread values).
static int GetNativePriority();
// Guaranteed to be non-zero.
uint32_t GetThreadId() const {
return tls32_.thin_lock_thread_id;
pid_t GetTid() const {
return tls32_.tid;
// Returns the java.lang.Thread's name, or null if this Thread* doesn't have a peer.
mirror::String* GetThreadName() const REQUIRES_SHARED(Locks::mutator_lock_);
// Sets 'name' to the java.lang.Thread's name. This requires no transition to managed code,
// allocation, or locking.
void GetThreadName(std::string& name) const;
// Sets the thread's name.
void SetThreadName(const char* name) REQUIRES_SHARED(Locks::mutator_lock_);
// Returns the thread-specific CPU-time clock in microseconds or -1 if unavailable.
uint64_t GetCpuMicroTime() const;
mirror::Object* GetPeer() const REQUIRES_SHARED(Locks::mutator_lock_) {
DCHECK(Thread::Current() == this) << "Use GetPeerFromOtherThread instead";
CHECK(tlsPtr_.jpeer == nullptr);
return tlsPtr_.opeer;
// GetPeer is not safe if called on another thread in the middle of the CC thread flip and
// the thread's stack may have not been flipped yet and peer may be a from-space (stale) ref.
// This function will explicitly mark/forward it.
mirror::Object* GetPeerFromOtherThread() const REQUIRES_SHARED(Locks::mutator_lock_);
bool HasPeer() const {
return tlsPtr_.jpeer != nullptr || tlsPtr_.opeer != nullptr;
RuntimeStats* GetStats() {
return &tls64_.stats;
bool IsStillStarting() const;
bool IsExceptionPending() const {
return tlsPtr_.exception != nullptr;
bool IsAsyncExceptionPending() const {
return tlsPtr_.async_exception != nullptr;
mirror::Throwable* GetException() const REQUIRES_SHARED(Locks::mutator_lock_) {
return tlsPtr_.exception;
void AssertPendingException() const;
void AssertPendingOOMException() const REQUIRES_SHARED(Locks::mutator_lock_);
void AssertNoPendingException() const;
void AssertNoPendingExceptionForNewException(const char* msg) const;
void SetException(ObjPtr<mirror::Throwable> new_exception) REQUIRES_SHARED(Locks::mutator_lock_);
// Set an exception that is asynchronously thrown from a different thread. This will be checked
// periodically and might overwrite the current 'Exception'. This can only be called from a
// checkpoint.
// The caller should also make sure that the thread has been deoptimized so that the exception
// could be detected on back-edges.
void SetAsyncException(ObjPtr<mirror::Throwable> new_exception)
void ClearException() REQUIRES_SHARED(Locks::mutator_lock_) {
tlsPtr_.exception = nullptr;
// Move the current async-exception to the main exception. This should be called when the current
// thread is ready to deal with any async exceptions. Returns true if there is an async exception
// that needs to be dealt with, false otherwise.
bool ObserveAsyncException() REQUIRES_SHARED(Locks::mutator_lock_);
// Find catch block and perform long jump to appropriate exception handle
NO_RETURN void QuickDeliverException() REQUIRES_SHARED(Locks::mutator_lock_);
Context* GetLongJumpContext();
void ReleaseLongJumpContext(Context* context) {
if (tlsPtr_.long_jump_context != nullptr) {
tlsPtr_.long_jump_context = context;
// Get the current method and dex pc. If there are errors in retrieving the dex pc, this will
// abort the runtime iff abort_on_error is true.
ArtMethod* GetCurrentMethod(uint32_t* dex_pc,
bool check_suspended = true,
bool abort_on_error = true) const
// Returns whether the given exception was thrown by the current Java method being executed
// (Note that this includes native Java methods).
bool IsExceptionThrownByCurrentMethod(ObjPtr<mirror::Throwable> exception) const
void SetTopOfStack(ArtMethod** top_method) {
void SetTopOfStackTagged(ArtMethod** top_method) {
void SetTopOfShadowStack(ShadowFrame* top) {
bool HasManagedStack() const {
return tlsPtr_.managed_stack.HasTopQuickFrame() || tlsPtr_.managed_stack.HasTopShadowFrame();
// If 'msg' is null, no detail message is set.
void ThrowNewException(const char* exception_class_descriptor, const char* msg)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
// If 'msg' is null, no detail message is set. An exception must be pending, and will be
// used as the new exception's cause.
void ThrowNewWrappedException(const char* exception_class_descriptor, const char* msg)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
void ThrowNewExceptionF(const char* exception_class_descriptor, const char* fmt, ...)
__attribute__((format(printf, 3, 4)))
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
void ThrowNewExceptionV(const char* exception_class_descriptor, const char* fmt, va_list ap)
REQUIRES_SHARED(Locks::mutator_lock_) REQUIRES(!Roles::uninterruptible_);
// OutOfMemoryError is special, because we need to pre-allocate an instance.
// Only the GC should call this.
void ThrowOutOfMemoryError(const char* msg) REQUIRES_SHARED(Locks::mutator_lock_)
static void Startup();
static void FinishStartup();
static void Shutdown();
// Notify this thread's thread-group that this thread has started.
// Note: the given thread-group is used as a fast path and verified in debug build. If the value
// is null, the thread's thread-group is loaded from the peer.
void NotifyThreadGroup(ScopedObjectAccessAlreadyRunnable& soa, jobject thread_group = nullptr)
// JNI methods
JNIEnvExt* GetJniEnv() const {
return tlsPtr_.jni_env;
// Convert a jobject into a Object*
ObjPtr<mirror::Object> DecodeJObject(jobject obj) const REQUIRES_SHARED(Locks::mutator_lock_);
// Checks if the weak global ref has been cleared by the GC without decoding it.
bool IsJWeakCleared(jweak obj) const REQUIRES_SHARED(Locks::mutator_lock_);
mirror::Object* GetMonitorEnterObject() const REQUIRES_SHARED(Locks::mutator_lock_) {
return tlsPtr_.monitor_enter_object;
void SetMonitorEnterObject(mirror::Object* obj) REQUIRES_SHARED(Locks::mutator_lock_) {
tlsPtr_.monitor_enter_object = obj;
// Implements java.lang.Thread.interrupted.
bool Interrupted();
// Implements java.lang.Thread.isInterrupted.
bool IsInterrupted();
void Interrupt(Thread* self) REQUIRES(!wait_mutex_);
void SetInterrupted(bool i) {, std::memory_order_seq_cst);
void Notify() REQUIRES(!wait_mutex_);
ALWAYS_INLINE void PoisonObjectPointers() {
ALWAYS_INLINE static void PoisonObjectPointersIfDebug();
ALWAYS_INLINE uintptr_t GetPoisonObjectCookie() const {
return poison_object_cookie_;
// Parking for 0ns of relative time means an untimed park, negative (though
// should be handled in java code) returns immediately
void Park(bool is_absolute, int64_t time) REQUIRES_SHARED(Locks::mutator_lock_);
void Unpark();
void NotifyLocked(Thread* self) REQUIRES(wait_mutex_);
Mutex* GetWaitMutex() const LOCK_RETURNED(wait_mutex_) {
return wait_mutex_;
ConditionVariable* GetWaitConditionVariable() const REQUIRES(wait_mutex_) {
return wait_cond_;
Monitor* GetWaitMonitor() const REQUIRES(wait_mutex_) {
return wait_monitor_;
void SetWaitMonitor(Monitor* mon) REQUIRES(wait_mutex_) {
wait_monitor_ = mon;
// Waiter link-list support.
Thread* GetWaitNext() const {
return tlsPtr_.wait_next;
void SetWaitNext(Thread* next) {
tlsPtr_.wait_next = next;
jobject GetClassLoaderOverride() {
return tlsPtr_.class_loader_override;
void SetClassLoaderOverride(jobject class_loader_override);
// Create the internal representation of a stack trace, that is more time
// and space efficient to compute than the StackTraceElement[].
template<bool kTransactionActive>
jobject CreateInternalStackTrace(const ScopedObjectAccessAlreadyRunnable& soa) const
// Convert an internal stack trace representation (returned by CreateInternalStackTrace) to a
// StackTraceElement[]. If output_array is null, a new array is created, otherwise as many
// frames as will fit are written into the given array. If stack_depth is non-null, it's updated
// with the number of valid frames in the returned array.
static jobjectArray InternalStackTraceToStackTraceElementArray(
const ScopedObjectAccessAlreadyRunnable& soa, jobject internal,
jobjectArray output_array = nullptr, int* stack_depth = nullptr)
jobjectArray CreateAnnotatedStackTrace(const ScopedObjectAccessAlreadyRunnable& soa) const
bool HasDebuggerShadowFrames() const {
return tlsPtr_.frame_id_to_shadow_frame != nullptr;
void VisitRoots(RootVisitor* visitor, VisitRootFlags flags)
void VerifyStack() REQUIRES_SHARED(Locks::mutator_lock_) {
if (kVerifyStack) {
// Offsets of various members of native Thread class, used by compiled code.
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThinLockIdOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, thin_lock_thread_id));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> InterruptedOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, interrupted));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadFlagsOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, state_and_flags));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> UseMterpOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, use_mterp));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> IsGcMarkingOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, is_gc_marking));
static constexpr size_t IsGcMarkingSize() {
return sizeof(tls32_.is_gc_marking);
// Deoptimize the Java stack.
void DeoptimizeWithDeoptimizationException(JValue* result) REQUIRES_SHARED(Locks::mutator_lock_);
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadOffsetFromTlsPtr(size_t tls_ptr_offset) {
size_t base = OFFSETOF_MEMBER(Thread, tlsPtr_);
size_t scale = (pointer_size > kRuntimePointerSize) ?
static_cast<size_t>(pointer_size) / static_cast<size_t>(kRuntimePointerSize) : 1;
size_t shrink = (kRuntimePointerSize > pointer_size) ?
static_cast<size_t>(kRuntimePointerSize) / static_cast<size_t>(pointer_size) : 1;
return ThreadOffset<pointer_size>(base + ((tls_ptr_offset * scale) / shrink));
static uint32_t QuickEntryPointOffsetWithSize(size_t quick_entrypoint_offset,
PointerSize pointer_size) {
if (pointer_size == PointerSize::k32) {
return QuickEntryPointOffset<PointerSize::k32>(quick_entrypoint_offset).
} else {
return QuickEntryPointOffset<PointerSize::k64>(quick_entrypoint_offset).
template<PointerSize pointer_size>
static ThreadOffset<pointer_size> QuickEntryPointOffset(size_t quick_entrypoint_offset) {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, quick_entrypoints) + quick_entrypoint_offset);
template<PointerSize pointer_size>
static ThreadOffset<pointer_size> JniEntryPointOffset(size_t jni_entrypoint_offset) {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, jni_entrypoints) + jni_entrypoint_offset);
// Return the entry point offset integer value for ReadBarrierMarkRegX, where X is `reg`.
template <PointerSize pointer_size>
static int32_t ReadBarrierMarkEntryPointsOffset(size_t reg) {
// The entry point list defines 30 ReadBarrierMarkRegX entry points.
DCHECK_LT(reg, 30u);
// The ReadBarrierMarkRegX entry points are ordered by increasing
// register number in Thread::tls_Ptr_.quick_entrypoints.
return QUICK_ENTRYPOINT_OFFSET(pointer_size, pReadBarrierMarkReg00).Int32Value()
+ static_cast<size_t>(pointer_size) * reg;
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> SelfOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, self));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> MterpCurrentIBaseOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, mterp_current_ibase));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ExceptionOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, exception));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> PeerOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, opeer));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> CardTableOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, card_table));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadSuspendTriggerOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, suspend_trigger));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadLocalPosOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadLocalEndOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadLocalObjectsOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> RosAllocRunsOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadLocalAllocStackTopOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> ThreadLocalAllocStackEndOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
// Size of stack less any space reserved for stack overflow
size_t GetStackSize() const {
return tlsPtr_.stack_size - (tlsPtr_.stack_end - tlsPtr_.stack_begin);
ALWAYS_INLINE uint8_t* GetStackEndForInterpreter(bool implicit_overflow_check) const;
uint8_t* GetStackEnd() const {
return tlsPtr_.stack_end;
// Set the stack end to that to be used during a stack overflow
void SetStackEndForStackOverflow() REQUIRES_SHARED(Locks::mutator_lock_);
// Set the stack end to that to be used during regular execution
ALWAYS_INLINE void ResetDefaultStackEnd();
bool IsHandlingStackOverflow() const {
return tlsPtr_.stack_end == tlsPtr_.stack_begin;
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> StackEndOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, stack_end));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> JniEnvOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, jni_env));
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> TopOfManagedStackOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, managed_stack) +
const ManagedStack* GetManagedStack() const {
return &tlsPtr_.managed_stack;
// Linked list recording fragments of managed stack.
void PushManagedStackFragment(ManagedStack* fragment) {
void PopManagedStackFragment(const ManagedStack& fragment) {
ALWAYS_INLINE ShadowFrame* PushShadowFrame(ShadowFrame* new_top_frame);
ALWAYS_INLINE ShadowFrame* PopShadowFrame();
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> TopShadowFrameOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, managed_stack) +
// Is the given obj in this thread's stack indirect reference table?
bool HandleScopeContains(jobject obj) const;
void HandleScopeVisitRoots(RootVisitor* visitor, pid_t thread_id)
BaseHandleScope* GetTopHandleScope() {
return tlsPtr_.top_handle_scope;
void PushHandleScope(BaseHandleScope* handle_scope) {
DCHECK_EQ(handle_scope->GetLink(), tlsPtr_.top_handle_scope);
tlsPtr_.top_handle_scope = handle_scope;
BaseHandleScope* PopHandleScope() {
BaseHandleScope* handle_scope = tlsPtr_.top_handle_scope;
DCHECK(handle_scope != nullptr);
tlsPtr_.top_handle_scope = tlsPtr_.top_handle_scope->GetLink();
return handle_scope;
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> TopHandleScopeOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values,
DebugInvokeReq* GetInvokeReq() const {
return tlsPtr_.debug_invoke_req;
SingleStepControl* GetSingleStepControl() const {
return tlsPtr_.single_step_control;
// Indicates whether this thread is ready to invoke a method for debugging. This
// is only true if the thread has been suspended by a debug event.
bool IsReadyForDebugInvoke() const {
return tls32_.ready_for_debug_invoke;
void SetReadyForDebugInvoke(bool ready) {
tls32_.ready_for_debug_invoke = ready;
bool IsDebugMethodEntry() const {
return tls32_.debug_method_entry_;
void SetDebugMethodEntry() {
tls32_.debug_method_entry_ = true;
void ClearDebugMethodEntry() {
tls32_.debug_method_entry_ = false;
bool GetIsGcMarking() const {
return tls32_.is_gc_marking;
void SetIsGcMarkingAndUpdateEntrypoints(bool is_marking);
bool GetWeakRefAccessEnabled() const {
return tls32_.weak_ref_access_enabled;
void SetWeakRefAccessEnabled(bool enabled) {
tls32_.weak_ref_access_enabled = enabled;
uint32_t GetDisableThreadFlipCount() const {
return tls32_.disable_thread_flip_count;
void IncrementDisableThreadFlipCount() {
void DecrementDisableThreadFlipCount() {
DCHECK_GT(tls32_.disable_thread_flip_count, 0U);
// Returns true if the thread is a runtime thread (eg from a ThreadPool).
bool IsRuntimeThread() const {
return is_runtime_thread_;
void SetIsRuntimeThread(bool is_runtime_thread) {
is_runtime_thread_ = is_runtime_thread;
// Returns true if the thread is allowed to load java classes.
bool CanLoadClasses() const;
// Activates single step control for debugging. The thread takes the
// ownership of the given SingleStepControl*. It is deleted by a call
// to DeactivateSingleStepControl or upon thread destruction.
void ActivateSingleStepControl(SingleStepControl* ssc);
// Deactivates single step control for debugging.
void DeactivateSingleStepControl();
// Sets debug invoke request for debugging. When the thread is resumed,
// it executes the method described by this request then sends the reply
// before suspending itself. The thread takes the ownership of the given
// DebugInvokeReq*. It is deleted by a call to ClearDebugInvokeReq.
void SetDebugInvokeReq(DebugInvokeReq* req);
// Clears debug invoke request for debugging. When the thread completes
// method invocation, it deletes its debug invoke request and suspends
// itself.
void ClearDebugInvokeReq();
// Returns the fake exception used to activate deoptimization.
static mirror::Throwable* GetDeoptimizationException() {
// Note that the mirror::Throwable must be aligned to kObjectAlignment or else it cannot be
// represented by ObjPtr.
return reinterpret_cast<mirror::Throwable*>(0x100);
// Currently deoptimization invokes verifier which can trigger class loading
// and execute Java code, so there might be nested deoptimizations happening.
// We need to save the ongoing deoptimization shadow frames and return
// values on stacks.
// 'from_code' denotes whether the deoptimization was explicitly made from
// compiled code.
// 'method_type' contains info on whether deoptimization should advance
// dex_pc.
void PushDeoptimizationContext(const JValue& return_value,
bool is_reference,
ObjPtr<mirror::Throwable> exception,
bool from_code,
DeoptimizationMethodType method_type)
void PopDeoptimizationContext(JValue* result,
ObjPtr<mirror::Throwable>* exception,
bool* from_code,
DeoptimizationMethodType* method_type)
void AssertHasDeoptimizationContext()
void PushStackedShadowFrame(ShadowFrame* sf, StackedShadowFrameType type);
ShadowFrame* PopStackedShadowFrame(StackedShadowFrameType type, bool must_be_present = true);
// For debugger, find the shadow frame that corresponds to a frame id.
// Or return null if there is none.
ShadowFrame* FindDebuggerShadowFrame(size_t frame_id)
// For debugger, find the bool array that keeps track of the updated vreg set
// for a frame id.
bool* GetUpdatedVRegFlags(size_t frame_id) REQUIRES_SHARED(Locks::mutator_lock_);
// For debugger, find the shadow frame that corresponds to a frame id. If
// one doesn't exist yet, create one and track it in frame_id_to_shadow_frame.
ShadowFrame* FindOrCreateDebuggerShadowFrame(size_t frame_id,
uint32_t num_vregs,
ArtMethod* method,
uint32_t dex_pc)
// Delete the entry that maps from frame_id to shadow_frame.
void RemoveDebuggerShadowFrameMapping(size_t frame_id)
std::deque<instrumentation::InstrumentationStackFrame>* GetInstrumentationStack() {
return tlsPtr_.instrumentation_stack;
std::vector<ArtMethod*>* GetStackTraceSample() const {
return tlsPtr_.deps_or_stack_trace_sample.stack_trace_sample;
void SetStackTraceSample(std::vector<ArtMethod*>* sample) {
tlsPtr_.deps_or_stack_trace_sample.stack_trace_sample = sample;
verifier::VerifierDeps* GetVerifierDeps() const {
return tlsPtr_.deps_or_stack_trace_sample.verifier_deps;
// It is the responsability of the caller to make sure the verifier_deps
// entry in the thread is cleared before destruction of the actual VerifierDeps
// object, or the thread.
void SetVerifierDeps(verifier::VerifierDeps* verifier_deps) {
DCHECK(verifier_deps == nullptr || tlsPtr_.deps_or_stack_trace_sample.verifier_deps == nullptr);
tlsPtr_.deps_or_stack_trace_sample.verifier_deps = verifier_deps;
uint64_t GetTraceClockBase() const {
return tls64_.trace_clock_base;
void SetTraceClockBase(uint64_t clock_base) {
tls64_.trace_clock_base = clock_base;
BaseMutex* GetHeldMutex(LockLevel level) const {
return tlsPtr_.held_mutexes[level];
void SetHeldMutex(LockLevel level, BaseMutex* mutex) {
tlsPtr_.held_mutexes[level] = mutex;
void ClearSuspendBarrier(AtomicInteger* target)
bool ReadFlag(ThreadFlag flag) const {
return (tls32_.state_and_flags.as_struct.flags & flag) != 0;
bool TestAllFlags() const {
return (tls32_.state_and_flags.as_struct.flags != 0);
void AtomicSetFlag(ThreadFlag flag) {
tls32_.state_and_flags.as_atomic_int.fetch_or(flag, std::memory_order_seq_cst);
void AtomicClearFlag(ThreadFlag flag) {
tls32_.state_and_flags.as_atomic_int.fetch_and(-1 ^ flag, std::memory_order_seq_cst);
bool UseMterp() const {
return tls32_.use_mterp.load();
void ResetQuickAllocEntryPointsForThread(bool is_marking);
// Returns the remaining space in the TLAB.
size_t TlabSize() const {
return tlsPtr_.thread_local_end - tlsPtr_.thread_local_pos;
// Returns the remaining space in the TLAB if we were to expand it to maximum capacity.
size_t TlabRemainingCapacity() const {
return tlsPtr_.thread_local_limit - tlsPtr_.thread_local_pos;
// Expand the TLAB by a fixed number of bytes. There must be enough capacity to do so.
void ExpandTlab(size_t bytes) {
tlsPtr_.thread_local_end += bytes;
DCHECK_LE(tlsPtr_.thread_local_end, tlsPtr_.thread_local_limit);
// Doesn't check that there is room.
mirror::Object* AllocTlab(size_t bytes);
void SetTlab(uint8_t* start, uint8_t* end, uint8_t* limit);
bool HasTlab() const;
uint8_t* GetTlabStart() {
return tlsPtr_.thread_local_start;
uint8_t* GetTlabPos() {
return tlsPtr_.thread_local_pos;
// Remove the suspend trigger for this thread by making the suspend_trigger_ TLS value
// equal to a valid pointer.
// TODO: does this need to atomic? I don't think so.
void RemoveSuspendTrigger() {
tlsPtr_.suspend_trigger = reinterpret_cast<uintptr_t*>(&tlsPtr_.suspend_trigger);
// Trigger a suspend check by making the suspend_trigger_ TLS value an invalid pointer.
// The next time a suspend check is done, it will load from the value at this address
// and trigger a SIGSEGV.
void TriggerSuspend() {
tlsPtr_.suspend_trigger = nullptr;
// Push an object onto the allocation stack.
bool PushOnThreadLocalAllocationStack(mirror::Object* obj)
// Set the thread local allocation pointers to the given pointers.
void SetThreadLocalAllocationStack(StackReference<mirror::Object>* start,
StackReference<mirror::Object>* end);
// Resets the thread local allocation pointers.
void RevokeThreadLocalAllocationStack();
size_t GetThreadLocalBytesAllocated() const {
return tlsPtr_.thread_local_end - tlsPtr_.thread_local_start;
size_t GetThreadLocalObjectsAllocated() const {
return tlsPtr_.thread_local_objects;
void* GetRosAllocRun(size_t index) const {
return tlsPtr_.rosalloc_runs[index];
void SetRosAllocRun(size_t index, void* run) {
tlsPtr_.rosalloc_runs[index] = run;
bool ProtectStack(bool fatal_on_error = true);
bool UnprotectStack();
void SetMterpCurrentIBase(void* ibase) {
tlsPtr_.mterp_current_ibase = ibase;
const void* GetMterpCurrentIBase() const {
return tlsPtr_.mterp_current_ibase;
bool HandlingSignal() const {
return tls32_.handling_signal_;
void SetHandlingSignal(bool handling_signal) {
tls32_.handling_signal_ = handling_signal;
bool IsTransitioningToRunnable() const {
return tls32_.is_transitioning_to_runnable;
void SetIsTransitioningToRunnable(bool value) {
tls32_.is_transitioning_to_runnable = value;
uint32_t DecrementForceInterpreterCount() REQUIRES(Locks::thread_list_lock_) {
return --tls32_.force_interpreter_count;
uint32_t IncrementForceInterpreterCount() REQUIRES(Locks::thread_list_lock_) {
return ++tls32_.force_interpreter_count;
void SetForceInterpreterCount(uint32_t value) REQUIRES(Locks::thread_list_lock_) {
tls32_.force_interpreter_count = value;
uint32_t ForceInterpreterCount() const {
return tls32_.force_interpreter_count;
bool IsForceInterpreter() const {
return tls32_.force_interpreter_count != 0;
void PushVerifier(verifier::MethodVerifier* verifier);
void PopVerifier(verifier::MethodVerifier* verifier);
void InitStringEntryPoints();
void ModifyDebugDisallowReadBarrier(int8_t delta) {
debug_disallow_read_barrier_ += delta;
uint8_t GetDebugDisallowReadBarrierCount() const {
return debug_disallow_read_barrier_;
// Gets the current TLSData associated with the key or nullptr if there isn't any. Note that users
// do not gain ownership of TLSData and must synchronize with SetCustomTls themselves to prevent
// it from being deleted.
TLSData* GetCustomTLS(const char* key) REQUIRES(!Locks::custom_tls_lock_);
// Sets the tls entry at 'key' to data. The thread takes ownership of the TLSData. The destructor
// will be run when the thread exits or when SetCustomTLS is called again with the same key.
void SetCustomTLS(const char* key, TLSData* data) REQUIRES(!Locks::custom_tls_lock_);
// Returns true if the current thread is the jit sensitive thread.
bool IsJitSensitiveThread() const {
return this == jit_sensitive_thread_;
bool IsSystemDaemon() const REQUIRES_SHARED(Locks::mutator_lock_);
// Returns true if StrictMode events are traced for the current thread.
static bool IsSensitiveThread() {
if (is_sensitive_thread_hook_ != nullptr) {
return (*is_sensitive_thread_hook_)();
return false;
// Set to the read barrier marking entrypoints to be non-null.
void SetReadBarrierEntrypoints();
static jobject CreateCompileTimePeer(JNIEnv* env,
const char* name,
bool as_daemon,
jobject thread_group)
ALWAYS_INLINE InterpreterCache* GetInterpreterCache() {
return &interpreter_cache_;
// Clear all thread-local interpreter caches.
// Since the caches are keyed by memory pointer to dex instructions, this must be
// called when any dex code is unloaded (before different code gets loaded at the
// same memory location).
// If presence of cache entry implies some pre-conditions, this must also be
// called if the pre-conditions might no longer hold true.
static void ClearAllInterpreterCaches();
template<PointerSize pointer_size>
static constexpr ThreadOffset<pointer_size> InterpreterCacheOffset() {
return ThreadOffset<pointer_size>(OFFSETOF_MEMBER(Thread, interpreter_cache_));
static constexpr int InterpreterCacheSizeLog2() {
return WhichPowerOf2(InterpreterCache::kSize);
explicit Thread(bool daemon);
~Thread() REQUIRES(!Locks::mutator_lock_, !Locks::thread_suspend_count_lock_);
void Destroy();
void NotifyInTheadList()
// Attaches the calling native thread to the runtime, returning the new native peer.
// Used to implement JNI AttachCurrentThread and AttachCurrentThreadAsDaemon calls.
template <typename PeerAction>
static Thread* Attach(const char* thread_name,
bool as_daemon,
PeerAction p);
void CreatePeer(const char* name, bool as_daemon, jobject thread_group);
template<bool kTransactionActive>
static void InitPeer(ScopedObjectAccessAlreadyRunnable& soa,
ObjPtr<mirror::Object> peer,
jboolean thread_is_daemon,
jobject thread_group,
jobject thread_name,
jint thread_priority)
// Avoid use, callers should use SetState. Used only by SignalCatcher::HandleSigQuit, ~Thread and
// Dbg::ManageDeoptimization.
ThreadState SetStateUnsafe(ThreadState new_state) {
ThreadState old_state = GetState();
if (old_state == kRunnable && new_state != kRunnable) {
// Need to run pending checkpoint and suspend barriers. Run checkpoints in runnable state in
// case they need to use a ScopedObjectAccess. If we are holding the mutator lock and a SOA
// attempts to TransitionFromSuspendedToRunnable, it results in a deadlock.
// Since we transitioned to a suspended state, check the pass barrier requests.
} else {
tls32_.state_and_flags.as_struct.state = new_state;
return old_state;
void VerifyStackImpl() REQUIRES_SHARED(Locks::mutator_lock_);
void DumpState(std::ostream& os) const REQUIRES_SHARED(Locks::mutator_lock_);
void DumpStack(std::ostream& os,
bool dump_native_stack = true,
BacktraceMap* backtrace_map = nullptr,
bool force_dump_stack = false) const
// Out-of-line conveniences for debugging in gdb.
static Thread* CurrentFromGdb(); // Like Thread::Current.
// Like Thread::Dump(std::cerr).
void DumpFromGdb() const REQUIRES_SHARED(Locks::mutator_lock_);
static void* CreateCallback(void* arg);
void HandleUncaughtExceptions(ScopedObjectAccessAlreadyRunnable& soa)
void RemoveFromThreadGroup(ScopedObjectAccessAlreadyRunnable& soa)
// Initialize a thread.
// The third parameter is not mandatory. If given, the thread will use this JNIEnvExt. In case
// Init succeeds, this means the thread takes ownership of it. If Init fails, it is the caller's
// responsibility to destroy the given JNIEnvExt. If the parameter is null, Init will try to
// create a JNIEnvExt on its own (and potentially fail at that stage, indicated by a return value
// of false).
bool Init(ThreadList*, JavaVMExt*, JNIEnvExt* jni_env_ext = nullptr)
void InitCardTable();
void InitCpu();
void CleanupCpu();
void InitTlsEntryPoints();
void InitTid();
void InitPthreadKeySelf();
bool InitStackHwm();
void SetUpAlternateSignalStack();
void TearDownAlternateSignalStack();
ALWAYS_INLINE void TransitionToSuspendedAndRunCheckpoints(ThreadState new_state)
REQUIRES(!Locks::thread_suspend_count_lock_, !Roles::uninterruptible_);
ALWAYS_INLINE void PassActiveSuspendBarriers()
REQUIRES(!Locks::thread_suspend_count_lock_, !Roles::uninterruptible_);
// Registers the current thread as the jit sensitive thread. Should be called just once.
static void SetJitSensitiveThread() {
if (jit_sensitive_thread_ == nullptr) {
jit_sensitive_thread_ = Thread::Current();
} else {
LOG(WARNING) << "Attempt to set the sensitive thread twice. Tid:"
<< Thread::Current()->GetTid();
static void SetSensitiveThreadHook(bool (*is_sensitive_thread_hook)()) {
is_sensitive_thread_hook_ = is_sensitive_thread_hook;
bool ModifySuspendCountInternal(Thread* self,
int delta,
AtomicInteger* suspend_barrier,
SuspendReason reason)
// Runs a single checkpoint function. If there are no more pending checkpoint functions it will
// clear the kCheckpointRequest flag. The caller is responsible for calling this in a loop until
// the kCheckpointRequest flag is cleared.
void RunCheckpointFunction();
void RunEmptyCheckpoint();
bool PassActiveSuspendBarriers(Thread* self)
// Install the protected region for implicit stack checks.
void InstallImplicitProtection();
template <bool kPrecise>
void VisitRoots(RootVisitor* visitor) REQUIRES_SHARED(Locks::mutator_lock_);
static bool IsAotCompiler();
void ReleaseLongJumpContextInternal();
// 32 bits of atomically changed state and flags. Keeping as 32 bits allows and atomic CAS to
// change from being Suspended to Runnable without a suspend request occurring.
union PACKED(4) StateAndFlags {
StateAndFlags() {}
struct PACKED(4) {
// Bitfield of flag values. Must be changed atomically so that flag values aren't lost. See
// ThreadFlags for bit field meanings.
volatile uint16_t flags;
// Holds the ThreadState. May be changed non-atomically between Suspended (ie not Runnable)
// transitions. Changing to Runnable requires that the suspend_request be part of the atomic
// operation. If a thread is suspended and a suspend_request is present, a thread may not
// change to Runnable as a GC or other operation is in progress.
volatile uint16_t state;
} as_struct;
AtomicInteger as_atomic_int;
volatile int32_t as_int;
// gcc does not handle struct with volatile member assignments correctly.
// See
static_assert(sizeof(StateAndFlags) == sizeof(int32_t), "Weird state_and_flags size");
static void ThreadExitCallback(void* arg);
// Maximum number of suspend barriers.
static constexpr uint32_t kMaxSuspendBarriers = 3;
// Has Thread::Startup been called?
static bool is_started_;
// TLS key used to retrieve the Thread*.
static pthread_key_t pthread_key_self_;
// Used to notify threads that they should attempt to resume, they will suspend again if
// their suspend count is > 0.
static ConditionVariable* resume_cond_ GUARDED_BY(Locks::thread_suspend_count_lock_);
// Hook passed by framework which returns true
// when StrictMode events are traced for the current thread.
static bool (*is_sensitive_thread_hook_)();
// Stores the jit sensitive thread (which for now is the UI thread).
static Thread* jit_sensitive_thread_;
// Thread local storage. Fields are grouped by size to enable 32 <-> 64 searching to account for
// pointer size differences. To encourage shorter encoding, more frequently used values appear
// first if possible.
struct PACKED(4) tls_32bit_sized_values {
// We have no control over the size of 'bool', but want our boolean fields
// to be 4-byte quantities.
typedef uint32_t bool32_t;
explicit tls_32bit_sized_values(bool is_daemon) :
suspend_count(0), debug_suspend_count(0), thin_lock_thread_id(0), tid(0),
daemon(is_daemon), throwing_OutOfMemoryError(false), no_thread_suspension(0),
thread_exit_check_count(0), handling_signal_(false),
is_transitioning_to_runnable(false), ready_for_debug_invoke(false),
debug_method_entry_(false), is_gc_marking(false), weak_ref_access_enabled(true),
disable_thread_flip_count(0), user_code_suspend_count(0), force_interpreter_count(0) {
union StateAndFlags state_and_flags;
static_assert(sizeof(union StateAndFlags) == sizeof(int32_t),
"Size of state_and_flags and int32 are different");
// A non-zero value is used to tell the current thread to enter a safe point
// at the next poll.
int suspend_count GUARDED_BY(Locks::thread_suspend_count_lock_);
// How much of 'suspend_count_' is by request of the debugger, used to set things right
// when the debugger detaches. Must be <= suspend_count_.
int debug_suspend_count GUARDED_BY(Locks::thread_suspend_count_lock_);
// Thin lock thread id. This is a small integer used by the thin lock implementation.
// This is not to be confused with the native thread's tid, nor is it the value returned
// by java.lang.Thread.getId --- this is a distinct value, used only for locking. One
// important difference between this id and the ids visible to managed code is that these
// ones get reused (to ensure that they fit in the number of bits available).
uint32_t thin_lock_thread_id;
// System thread id.
uint32_t tid;
// Is the thread a daemon?
const bool32_t daemon;
// A boolean telling us whether we're recursively throwing OOME.
bool32_t throwing_OutOfMemoryError;
// A positive value implies we're in a region where thread suspension isn't expected.
uint32_t no_thread_suspension;
// How many times has our pthread key's destructor been called?
uint32_t thread_exit_check_count;
// True if signal is being handled by this thread.
bool32_t handling_signal_;
// True if the thread is in TransitionFromSuspendedToRunnable(). This is used to distinguish the
// non-runnable threads (eg. kNative, kWaiting) that are about to transition to runnable from
// the rest of them.
bool32_t is_transitioning_to_runnable;
// True if the thread has been suspended by a debugger event. This is
// used to invoke method from the debugger which is only allowed when
// the thread is suspended by an event.
bool32_t ready_for_debug_invoke;
// True if the thread enters a method. This is used to detect method entry
// event for the debugger.
bool32_t debug_method_entry_;
// True if the GC is in the marking phase. This is used for the CC collector only. This is
// thread local so that we can simplify the logic to check for the fast path of read barriers of
// GC roots.
bool32_t is_gc_marking;
// Thread "interrupted" status; stays raised until queried or thrown.
Atomic<bool32_t> interrupted;
AtomicInteger park_state_;
// True if the thread is allowed to access a weak ref (Reference::GetReferent() and system
// weaks) and to potentially mark an object alive/gray. This is used for concurrent reference
// processing of the CC collector only. This is thread local so that we can enable/disable weak
// ref access by using a checkpoint and avoid a race around the time weak ref access gets
// disabled and concurrent reference processing begins (if weak ref access is disabled during a
// pause, this is not an issue.) Other collectors use Runtime::DisallowNewSystemWeaks() and
// ReferenceProcessor::EnableSlowPath().
bool32_t weak_ref_access_enabled;
// A thread local version of Heap::disable_thread_flip_count_. This keeps track of how many
// levels of (nested) JNI critical sections the thread is in and is used to detect a nested JNI
// critical section enter.
uint32_t disable_thread_flip_count;
// How much of 'suspend_count_' is by request of user code, used to distinguish threads
// suspended by the runtime from those suspended by user code.
// This should have GUARDED_BY(Locks::user_code_suspension_lock_) but auto analysis cannot be
// told that AssertHeld should be good enough.
int user_code_suspend_count GUARDED_BY(Locks::thread_suspend_count_lock_);
// Count of how many times this thread has been forced to interpreter. If this is not 0 the
// thread must remain in interpreted code as much as possible.
uint32_t force_interpreter_count;
// True if everything is in the ideal state for fast interpretation.
// False if we need to switch to the C++ interpreter to handle special cases.
std::atomic<bool32_t> use_mterp;
} tls32_;
struct PACKED(8) tls_64bit_sized_values {
tls_64bit_sized_values() : trace_clock_base(0) {
// The clock base used for tracing.
uint64_t trace_clock_base;
RuntimeStats stats;
} tls64_;
struct PACKED(sizeof(void*)) tls_ptr_sized_values {
tls_ptr_sized_values() : card_table(nullptr), exception(nullptr), stack_end(nullptr),
managed_stack(), suspend_trigger(nullptr), jni_env(nullptr), tmp_jni_env(nullptr),
self(nullptr), opeer(nullptr), jpeer(nullptr), stack_begin(nullptr), stack_size(0),
deps_or_stack_trace_sample(), wait_next(nullptr), monitor_enter_object(nullptr),
top_handle_scope(nullptr), class_loader_override(nullptr), long_jump_context(nullptr),
instrumentation_stack(nullptr), debug_invoke_req(nullptr), single_step_control(nullptr),
stacked_shadow_frame_record(nullptr), deoptimization_context_stack(nullptr),
frame_id_to_shadow_frame(nullptr), name(nullptr), pthread_self(0),
last_no_thread_suspension_cause(nullptr), checkpoint_function(nullptr),
thread_local_start(nullptr), thread_local_pos(nullptr), thread_local_end(nullptr),
thread_local_objects(0), mterp_current_ibase(nullptr), thread_local_alloc_stack_top(nullptr),
flip_function(nullptr), method_verifier(nullptr), thread_local_mark_stack(nullptr),
async_exception(nullptr) {
std::fill(held_mutexes, held_mutexes + kLockLevelCount, nullptr);
// The biased card table, see CardTable for details.
uint8_t* card_table;
// The pending exception or null.
mirror::Throwable* exception;
// The end of this thread's stack. This is the lowest safely-addressable address on the stack.
// We leave extra space so there's room for the code that throws StackOverflowError.
uint8_t* stack_end;
// The top of the managed stack often manipulated directly by compiler generated code.
ManagedStack managed_stack;
// In certain modes, setting this to 0 will trigger a SEGV and thus a suspend check. It is
// normally set to the address of itself.
uintptr_t* suspend_trigger;
// Every thread may have an associated JNI environment
JNIEnvExt* jni_env;
// Temporary storage to transfer a pre-allocated JNIEnvExt from the creating thread to the
// created thread.
JNIEnvExt* tmp_jni_env;
// Initialized to "this". On certain architectures (such as x86) reading off of Thread::Current
// is easy but getting the address of Thread::Current is hard. This field can be read off of
// Thread::Current to give the address.
Thread* self;
// Our managed peer (an instance of java.lang.Thread). The jobject version is used during thread
// start up, until the thread is registered and the local opeer_ is used.
mirror::Object* opeer;
jobject jpeer;
// The "lowest addressable byte" of the stack.
uint8_t* stack_begin;
// Size of the stack.
size_t stack_size;
// Sampling profiler and AOT verification cannot happen on the same run, so we share
// the same entry for the stack trace and the verifier deps.
union DepsOrStackTraceSample {
DepsOrStackTraceSample() {
verifier_deps = nullptr;
stack_trace_sample = nullptr;
// Pointer to previous stack trace captured by sampling profiler.
std::vector<ArtMethod*>* stack_trace_sample;
// When doing AOT verification, per-thread VerifierDeps.
verifier::VerifierDeps* verifier_deps;
} deps_or_stack_trace_sample;
// The next thread in the wait set this thread is part of or null if not waiting.
Thread* wait_next;
// If we're blocked in MonitorEnter, this is the object we're trying to lock.
mirror::Object* monitor_enter_object;
// Top of linked list of handle scopes or null for none.
BaseHandleScope* top_handle_scope;
// Needed to get the right ClassLoader in JNI_OnLoad, but also
// useful for testing.
jobject class_loader_override;
// Thread local, lazily allocated, long jump context. Used to deliver exceptions.
Context* long_jump_context;
// Additional stack used by method instrumentation to store method and return pc values.
// Stored as a pointer since std::deque is not PACKED.
std::deque<instrumentation::InstrumentationStackFrame>* instrumentation_stack;
// JDWP invoke-during-breakpoint support.
DebugInvokeReq* debug_invoke_req;
// JDWP single-stepping support.
SingleStepControl* single_step_control;
// For gc purpose, a shadow frame record stack that keeps track of:
// 1) shadow frames under construction.
// 2) deoptimization shadow frames.
StackedShadowFrameRecord* stacked_shadow_frame_record;
// Deoptimization return value record stack.
DeoptimizationContextRecord* deoptimization_context_stack;
// For debugger, a linked list that keeps the mapping from frame_id to shadow frame.
// Shadow frames may be created before deoptimization happens so that the debugger can
// set local values there first.
FrameIdToShadowFrame* frame_id_to_shadow_frame;
// A cached copy of the java.lang.Thread's name.
std::string* name;
// A cached pthread_t for the pthread underlying this Thread*.
pthread_t pthread_self;
// If no_thread_suspension_ is > 0, what is causing that assertion.
const char* last_no_thread_suspension_cause;
// Pending checkpoint function or null if non-pending. If this checkpoint is set and someone\
// requests another checkpoint, it goes to the checkpoint overflow list.
Closure* checkpoint_function GUARDED_BY(Locks::thread_suspend_count_lock_);
// Pending barriers that require passing or NULL if non-pending. Installation guarding by
// Locks::thread_suspend_count_lock_.
// They work effectively as art::Barrier, but implemented directly using AtomicInteger and futex
// to avoid additional cost of a mutex and a condition variable, as used in art::Barrier.
AtomicInteger* active_suspend_barriers[kMaxSuspendBarriers];
// Thread-local allocation pointer. Moved here to force alignment for thread_local_pos on ARM.
uint8_t* thread_local_start;
// thread_local_pos and thread_local_end must be consecutive for ldrd and are 8 byte aligned for
// potentially better performance.
uint8_t* thread_local_pos;
uint8_t* thread_local_end;
// Thread local limit is how much we can expand the thread local buffer to, it is greater or
// equal to thread_local_end.
uint8_t* thread_local_limit;
size_t thread_local_objects;
// Entrypoint function pointers.
// TODO: move this to more of a global offset table model to avoid per-thread duplication.
JniEntryPoints jni_entrypoints;
QuickEntryPoints quick_entrypoints;
// Mterp jump table base.
void* mterp_current_ibase;
// There are RosAlloc::kNumThreadLocalSizeBrackets thread-local size brackets per thread.
void* rosalloc_runs[kNumRosAllocThreadLocalSizeBracketsInThread];
// Thread-local allocation stack data/routines.
StackReference<mirror::Object>* thread_local_alloc_stack_top;
StackReference<mirror::Object>* thread_local_alloc_stack_end;
// Support for Mutex lock hierarchy bug detection.
BaseMutex* held_mutexes[kLockLevelCount];
// The function used for thread flip.
Closure* flip_function;
// Current method verifier, used for root marking.
verifier::MethodVerifier* method_verifier;
// Thread-local mark stack for the concurrent copying collector.
gc::accounting::AtomicStack<mirror::Object>* thread_local_mark_stack;
// The pending async-exception or null.
mirror::Throwable* async_exception;
} tlsPtr_;
// Small thread-local cache to be used from the interpreter.
// It is keyed by dex instruction pointer.
// The value is opcode-depended (e.g. field offset).
InterpreterCache interpreter_cache_;
// All fields below this line should not be accessed by native code. This means these fields can
// be modified, rearranged, added or removed without having to modify asm_support.h
// Guards the 'wait_monitor_' members.
// Condition variable waited upon during a wait.
ConditionVariable* wait_cond_ GUARDED_BY(wait_mutex_);
// Pointer to the monitor lock we're currently waiting on or null if not waiting.
Monitor* wait_monitor_ GUARDED_BY(wait_mutex_);
// Debug disable read barrier count, only is checked for debug builds and only in the runtime.
uint8_t debug_disallow_read_barrier_ = 0;
// Note that it is not in the packed struct, may not be accessed for cross compilation.
uintptr_t poison_object_cookie_ = 0;
// Pending extra checkpoints if checkpoint_function_ is already used.
std::list<Closure*> checkpoint_overflow_ GUARDED_BY(Locks::thread_suspend_count_lock_);
// Custom TLS field that can be used by plugins or the runtime. Should not be accessed directly by
// compiled code or entrypoints.
SafeMap<std::string, std::unique_ptr<TLSData>> custom_tls_ GUARDED_BY(Locks::custom_tls_lock_);
// True if the thread is some form of runtime thread (ex, GC or JIT).
bool is_runtime_thread_;
friend class Dbg; // For SetStateUnsafe.
friend class gc::collector::SemiSpace; // For getting stack traces.
friend class Runtime; // For CreatePeer.
friend class QuickExceptionHandler; // For dumping the stack.
friend class ScopedThreadStateChange;
friend class StubTest; // For accessing entrypoints.
friend class ThreadList; // For ~Thread and Destroy.
friend class EntrypointsOrderTest; // To test the order of tls entries.
class SCOPED_CAPABILITY ScopedAssertNoThreadSuspension {
ALWAYS_INLINE ScopedAssertNoThreadSuspension(const char* cause,
bool enabled = true)
: enabled_(enabled) {
if (!enabled_) {
if (kIsDebugBuild) {
self_ = Thread::Current();
old_cause_ = self_->StartAssertNoThreadSuspension(cause);
} else {
Roles::uninterruptible_.Acquire(); // No-op.
ALWAYS_INLINE ~ScopedAssertNoThreadSuspension() RELEASE(Roles::uninterruptible_) {
if (!enabled_) {
if (kIsDebugBuild) {
} else {
Roles::uninterruptible_.Release(); // No-op.
Thread* self_;
const bool enabled_;
const char* old_cause_;
class ScopedStackedShadowFramePusher {
ScopedStackedShadowFramePusher(Thread* self, ShadowFrame* sf, StackedShadowFrameType type)
: self_(self), type_(type) {
self_->PushStackedShadowFrame(sf, type);
~ScopedStackedShadowFramePusher() {
Thread* const self_;
const StackedShadowFrameType type_;
// Only works for debug builds.
class ScopedDebugDisallowReadBarriers {
explicit ScopedDebugDisallowReadBarriers(Thread* self) : self_(self) {
~ScopedDebugDisallowReadBarriers() {
Thread* const self_;
class ScopedTransitioningToRunnable : public ValueObject {
explicit ScopedTransitioningToRunnable(Thread* self)
: self_(self) {
DCHECK_EQ(self, Thread::Current());
if (kUseReadBarrier) {
~ScopedTransitioningToRunnable() {
if (kUseReadBarrier) {
Thread* const self_;
class ThreadLifecycleCallback {
virtual ~ThreadLifecycleCallback() {}
virtual void ThreadStart(Thread* self) REQUIRES_SHARED(Locks::mutator_lock_) = 0;
virtual void ThreadDeath(Thread* self) REQUIRES_SHARED(Locks::mutator_lock_) = 0;
std::ostream& operator<<(std::ostream& os, const Thread& thread);
std::ostream& operator<<(std::ostream& os, const StackedShadowFrameType& thread);
} // namespace art