blob: 9311bef48ade12f771a1fb666926d048d781af40 [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 <bitset>
#include <deque>
#include <iosfwd>
#include <list>
#include <memory>
#include <setjmp.h>
#include <string>
#include "arch/context.h"
#include "arch/instruction_set.h"
#include "atomic.h"
#include "base/macros.h"
#include "base/mutex.h"
#include "entrypoints/interpreter/interpreter_entrypoints.h"
#include "entrypoints/jni/jni_entrypoints.h"
#include "entrypoints/quick/quick_entrypoints.h"
#include "globals.h"
#include "handle_scope.h"
#include "instrumentation.h"
#include "jvalue.h"
#include "object_callbacks.h"
#include "offsets.h"
#include "runtime_stats.h"
#include "stack.h"
#include "thread_state.h"
namespace art {
namespace gc {
namespace collector {
class SemiSpace;
} // namespace collector
} // namespace gc
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;
} // namespace verifier
class ArtMethod;
class BaseMutex;
class ClassLinker;
class Closure;
class Context;
struct DebugInvokeReq;
class DeoptimizationReturnValueRecord;
class DexFile;
class JavaVMExt;
struct JNIEnvExt;
class Monitor;
class Runtime;
class ScopedObjectAccessAlreadyRunnable;
class ShadowFrame;
class SingleStepControl;
class StackedShadowFrameRecord;
class Thread;
class ThreadList;
// 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.
enum class StackedShadowFrameType {
static constexpr size_t kNumRosAllocThreadLocalSizeBrackets = 34;
// 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 {
// For implicit overflow checks we reserve an extra piece of memory at the bottom
// of the stack (lowest memory). The higher portion of the memory
// is protected against reads and the lower is available for use while
// throwing the StackOverflow exception.
static constexpr size_t kStackOverflowProtectedSize = 4 * KB;
static const size_t kStackOverflowImplicitCheckSize;
// 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);
// 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() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Process pending thread suspension request and handle if pending.
void CheckSuspend() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
static Thread* FromManagedThread(const ScopedObjectAccessAlreadyRunnable& ts,
mirror::Object* thread_peer)
static Thread* FromManagedThread(const ScopedObjectAccessAlreadyRunnable& ts, jobject thread)
// Translates 172 to pAllocArrayFromCode and so on.
template<size_t 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) const
void DumpJavaStack(std::ostream& os) 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 EXCLUSIVE_LOCKS_REQUIRED(Locks::thread_suspend_count_lock_) {
return tls32_.suspend_count;
int GetDebugSuspendCount() const EXCLUSIVE_LOCKS_REQUIRED(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;
void ModifySuspendCount(Thread* self, int delta, bool for_debugger)
bool RequestCheckpoint(Closure* function)
void SetFlipFunction(Closure* function);
Closure* GetFlipFunction();
// 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_.
ThreadState TransitionFromSuspendedToRunnable()
// Transition from runnable into a state where mutator privileges are denied. Releases share of
// mutator lock.
void TransitionFromRunnableToSuspended(ThreadState new_state)
// Once called thread suspension will cause an assertion failure.
const char* StartAssertNoThreadSuspension(const char* cause) {
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) {
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;
void AssertThreadSuspensionIsAllowable(bool check_locks = true) const;
bool IsDaemon() const {
return tls32_.daemon;
bool HoldsLock(mirror::Object*) const SHARED_LOCKS_REQUIRED(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();
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 ScopedObjectAccessAlreadyRunnable& ts) const
// 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) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Returns the thread-specific CPU-time clock in microseconds or -1 if unavailable.
uint64_t GetCpuMicroTime() const;
mirror::Object* GetPeer() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
CHECK(tlsPtr_.jpeer == nullptr);
return tlsPtr_.opeer;
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;
mirror::Throwable* GetException() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return tlsPtr_.exception;
void AssertPendingException() const;
void AssertPendingOOMException() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void AssertNoPendingException() const;
void AssertNoPendingExceptionForNewException(const char* msg) const;
void SetException(mirror::Throwable* new_exception)
SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
CHECK(new_exception != nullptr);
// TODO: DCHECK(!IsExceptionPending());
tlsPtr_.exception = new_exception;
void ClearException() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
tlsPtr_.exception = nullptr;
// Find catch block and perform long jump to appropriate exception handle
NO_RETURN void QuickDeliverException() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
Context* GetLongJumpContext();
void ReleaseLongJumpContext(Context* context) {
if (tlsPtr_.long_jump_context != nullptr) {
// Each QuickExceptionHandler gets a long jump context and uses
// it for doing the long jump, after finding catch blocks/doing deoptimization.
// Both finding catch blocks and deoptimization can trigger another
// exception such as a result of class loading. So there can be nested
// cases of exception handling and multiple contexts being used.
// ReleaseLongJumpContext tries to save the context in tlsPtr_.long_jump_context
// for reuse so there is no need to always allocate a new one each time when
// getting a context. Since we only keep one context for reuse, delete the
// existing one since the passed in context is yet to be used for longjump.
delete tlsPtr_.long_jump_context;
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 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(mirror::Throwable* exception) const
void SetTopOfStack(ArtMethod** top_method) {
void SetTopOfShadowStack(ShadowFrame* top) {
bool HasManagedStack() const {
return (tlsPtr_.managed_stack.GetTopQuickFrame() != nullptr) ||
(tlsPtr_.managed_stack.GetTopShadowFrame() != nullptr);
// If 'msg' is null, no detail message is set.
void ThrowNewException(const char* exception_class_descriptor, const char* msg)
// 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)
void ThrowNewExceptionF(const char* exception_class_descriptor, const char* fmt, ...)
__attribute__((format(printf, 3, 4)))
void ThrowNewExceptionV(const char* exception_class_descriptor, const char* fmt, va_list ap)
// OutOfMemoryError is special, because we need to pre-allocate an instance.
// Only the GC should call this.
void ThrowOutOfMemoryError(const char* msg) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
static void Startup();
static void FinishStartup();
static void Shutdown();
// JNI methods
JNIEnvExt* GetJniEnv() const {
return tlsPtr_.jni_env;
// Convert a jobject into a Object*
mirror::Object* DecodeJObject(jobject obj) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
mirror::Object* GetMonitorEnterObject() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return tlsPtr_.monitor_enter_object;
void SetMonitorEnterObject(mirror::Object* obj) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
tlsPtr_.monitor_enter_object = obj;
// Implements java.lang.Thread.interrupted.
bool Interrupted() LOCKS_EXCLUDED(wait_mutex_);
// Implements java.lang.Thread.isInterrupted.
bool IsInterrupted() LOCKS_EXCLUDED(wait_mutex_);
bool IsInterruptedLocked() EXCLUSIVE_LOCKS_REQUIRED(wait_mutex_) {
return interrupted_;
void Interrupt(Thread* self) LOCKS_EXCLUDED(wait_mutex_);
void SetInterruptedLocked(bool i) EXCLUSIVE_LOCKS_REQUIRED(wait_mutex_) {
interrupted_ = i;
void Notify() LOCKS_EXCLUDED(wait_mutex_);
void NotifyLocked(Thread* self) EXCLUSIVE_LOCKS_REQUIRED(wait_mutex_);
Mutex* GetWaitMutex() const LOCK_RETURNED(wait_mutex_) {
return wait_mutex_;
ConditionVariable* GetWaitConditionVariable() const EXCLUSIVE_LOCKS_REQUIRED(wait_mutex_) {
return wait_cond_;
Monitor* GetWaitMonitor() const EXCLUSIVE_LOCKS_REQUIRED(wait_mutex_) {
return wait_monitor_;
void SetWaitMonitor(Monitor* mon) EXCLUSIVE_LOCKS_REQUIRED(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)
void VisitRoots(RootVisitor* visitor) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
ALWAYS_INLINE void VerifyStack() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Offsets of various members of native Thread class, used by compiled code.
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThinLockIdOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, thin_lock_thread_id));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadFlagsOffset() {
return ThreadOffset<pointer_size>(
OFFSETOF_MEMBER(Thread, tls32_) +
OFFSETOF_MEMBER(tls_32bit_sized_values, state_and_flags));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadOffsetFromTlsPtr(size_t tls_ptr_offset) {
size_t base = OFFSETOF_MEMBER(Thread, tlsPtr_);
size_t scale;
size_t shrink;
if (pointer_size == sizeof(void*)) {
scale = 1;
shrink = 1;
} else if (pointer_size > sizeof(void*)) {
scale = pointer_size / sizeof(void*);
shrink = 1;
} else {
DCHECK_GT(sizeof(void*), pointer_size);
scale = 1;
shrink = sizeof(void*) / pointer_size;
return ThreadOffset<pointer_size>(base + ((tls_ptr_offset * scale) / shrink));
static uint32_t QuickEntryPointOffsetWithSize(size_t quick_entrypoint_offset,
size_t pointer_size) {
DCHECK(pointer_size == 4 || pointer_size == 8) << pointer_size;
if (pointer_size == 4) {
return QuickEntryPointOffset<4>(quick_entrypoint_offset).Uint32Value();
} else {
return QuickEntryPointOffset<8>(quick_entrypoint_offset).Uint32Value();
template<size_t 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<size_t pointer_size>
static ThreadOffset<pointer_size> InterpreterEntryPointOffset(size_t interp_entrypoint_offset) {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, interpreter_entrypoints) + interp_entrypoint_offset);
template<size_t 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);
template<size_t pointer_size>
static ThreadOffset<pointer_size> SelfOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, self));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ExceptionOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, exception));
template<size_t pointer_size>
static ThreadOffset<pointer_size> PeerOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, opeer));
template<size_t pointer_size>
static ThreadOffset<pointer_size> CardTableOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, card_table));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadSuspendTriggerOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, suspend_trigger));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadLocalPosOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, thread_local_pos));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadLocalEndOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, thread_local_end));
template<size_t pointer_size>
static ThreadOffset<pointer_size> ThreadLocalObjectsOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(OFFSETOF_MEMBER(tls_ptr_sized_values, thread_local_objects));
// Size of stack less any space reserved for stack overflow
size_t GetStackSize() const {
return tlsPtr_.stack_size - (tlsPtr_.stack_end - tlsPtr_.stack_begin);
uint8_t* GetStackEndForInterpreter(bool implicit_overflow_check) const {
if (implicit_overflow_check) {
// The interpreter needs the extra overflow bytes that stack_end does
// not include.
return tlsPtr_.stack_end + GetStackOverflowReservedBytes(kRuntimeISA);
} else {
return tlsPtr_.stack_end;
uint8_t* GetStackEnd() const {
return tlsPtr_.stack_end;
// Set the stack end to that to be used during a stack overflow
void SetStackEndForStackOverflow() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// Set the stack end to that to be used during regular execution
void ResetDefaultStackEnd() {
// Our stacks grow down, so we want stack_end_ to be near there, but reserving enough room
// to throw a StackOverflowError.
tlsPtr_.stack_end = tlsPtr_.stack_begin + GetStackOverflowReservedBytes(kRuntimeISA);
// Install the protected region for implicit stack checks.
void InstallImplicitProtection();
bool IsHandlingStackOverflow() const {
return tlsPtr_.stack_end == tlsPtr_.stack_begin;
template<size_t pointer_size>
static ThreadOffset<pointer_size> StackEndOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, stack_end));
template<size_t pointer_size>
static ThreadOffset<pointer_size> JniEnvOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, jni_env));
template<size_t pointer_size>
static 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) {
ShadowFrame* PushShadowFrame(ShadowFrame* new_top_frame) {
return tlsPtr_.managed_stack.PushShadowFrame(new_top_frame);
ShadowFrame* PopShadowFrame() {
return tlsPtr_.managed_stack.PopShadowFrame();
template<size_t pointer_size>
static ThreadOffset<pointer_size> TopShadowFrameOffset() {
return ThreadOffsetFromTlsPtr<pointer_size>(
OFFSETOF_MEMBER(tls_ptr_sized_values, managed_stack) +
// Number of references allocated in JNI ShadowFrames on this thread.
size_t NumJniShadowFrameReferences() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return tlsPtr_.managed_stack.NumJniShadowFrameReferences();
// Number of references in handle scope on this thread.
size_t NumHandleReferences();
// Number of references allocated in handle scopes & JNI shadow frames on this thread.
size_t NumStackReferences() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
return NumHandleReferences() + NumJniShadowFrameReferences();
// Is the given obj in this thread's stack indirect reference table?
bool HandleScopeContains(jobject obj) const;
void HandleScopeVisitRoots(RootVisitor* visitor, uint32_t thread_id)
HandleScope* GetTopHandleScope() {
return tlsPtr_.top_handle_scope;
void PushHandleScope(HandleScope* handle_scope) {
DCHECK_EQ(handle_scope->GetLink(), tlsPtr_.top_handle_scope);
tlsPtr_.top_handle_scope = handle_scope;
HandleScope* PopHandleScope() {
HandleScope* handle_scope = tlsPtr_.top_handle_scope;
DCHECK(handle_scope != nullptr);
tlsPtr_.top_handle_scope = tlsPtr_.top_handle_scope->GetLink();
return handle_scope;
template<size_t pointer_size>
static 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;
// 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 suspends itself.
// The thread does not take ownership of the given DebugInvokeReq*, it is
// owned by the JDWP thread which is waiting for the execution of the
// method.
void SetDebugInvokeReq(DebugInvokeReq* req);
// Clears debug invoke request for debugging. When the thread completes
// method invocation, it clears its debug invoke request, signals the
// JDWP thread and suspends itself.
void ClearDebugInvokeReq();
// Returns the fake exception used to activate deoptimization.
static mirror::Throwable* GetDeoptimizationException() {
return reinterpret_cast<mirror::Throwable*>(-1);
// 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.
void SetDeoptimizationReturnValue(const JValue& ret_val, bool is_reference) {
tls32_.deoptimization_return_value_is_reference = is_reference;
bool IsDeoptimizationReturnValueReference() {
return tls32_.deoptimization_return_value_is_reference;
void ClearDeoptimizationReturnValue() {
tls32_.deoptimization_return_value_is_reference = false;
void PushAndClearDeoptimizationReturnValue();
JValue PopDeoptimizationReturnValue();
void PushStackedShadowFrame(ShadowFrame* sf, StackedShadowFrameType type);
ShadowFrame* PopStackedShadowFrame(StackedShadowFrameType type);
std::deque<instrumentation::InstrumentationStackFrame>* GetInstrumentationStack() {
return tlsPtr_.instrumentation_stack;
std::vector<ArtMethod*>* GetStackTraceSample() const {
return tlsPtr_.stack_trace_sample;
void SetStackTraceSample(std::vector<ArtMethod*>* sample) {
tlsPtr_.stack_trace_sample = sample;
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 RunCheckpointFunction();
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) {
void AtomicClearFlag(ThreadFlag flag) {
tls32_.state_and_flags.as_atomic_int.FetchAndAndSequentiallyConsistent(-1 ^ flag);
void ResetQuickAllocEntryPointsForThread();
// Returns the remaining space in the TLAB.
size_t TlabSize() const;
// Doesn't check that there is room.
mirror::Object* AllocTlab(size_t bytes);
void SetTlab(uint8_t* start, uint8_t* end);
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;
void ProtectStack();
bool UnprotectStack();
void NoteSignalBeingHandled() {
if (tls32_.handling_signal_) {
LOG(FATAL) << "Detected signal while processing a signal";
tls32_.handling_signal_ = true;
void NoteSignalHandlerDone() {
tls32_.handling_signal_ = false;
jmp_buf* GetNestedSignalState() {
return tlsPtr_.nested_signal_state;
bool IsSuspendedAtSuspendCheck() const {
return tls32_.suspended_at_suspend_check;
void PushVerifier(verifier::MethodVerifier* verifier);
void PopVerifier(verifier::MethodVerifier* verifier);
void InitStringEntryPoints();
explicit Thread(bool daemon);
~Thread() LOCKS_EXCLUDED(Locks::mutator_lock_,
void Destroy();
void CreatePeer(const char* name, bool as_daemon, jobject thread_group);
template<bool kTransactionActive>
void InitPeer(ScopedObjectAccess& soa, 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::Disconnected.
ThreadState SetStateUnsafe(ThreadState new_state) {
ThreadState old_state = GetState();
tls32_.state_and_flags.as_struct.state = new_state;
return old_state;
void VerifyStackImpl() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void DumpState(std::ostream& os) const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
void DumpStack(std::ostream& os) const
// Out-of-line conveniences for debugging in gdb.
static Thread* CurrentFromGdb(); // Like Thread::Current.
// Like Thread::Dump(std::cerr).
void DumpFromGdb() const SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
static void* CreateCallback(void* arg);
void HandleUncaughtExceptions(ScopedObjectAccess& soa)
void RemoveFromThreadGroup(ScopedObjectAccess& soa) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
// 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();
// 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 checkpoint functions.
static constexpr uint32_t kMaxCheckpoints = 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_);
// 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),
deoptimization_return_value_is_reference(false), suspended_at_suspend_check(false),
ready_for_debug_invoke(false), debug_method_entry_(false) {
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 return value for interpreter after deoptimization is a reference.
// For gc purpose.
bool32_t deoptimization_return_value_is_reference;
// True if the thread is suspended in FullSuspendCheck(). This is
// used to distinguish runnable threads that are suspended due to
// a normal suspend check from other threads.
bool32_t suspended_at_suspend_check;
// 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_;
} tls32_;
struct PACKED(8) tls_64bit_sized_values {
tls_64bit_sized_values() : trace_clock_base(0), deoptimization_return_value() {
// The clock base used for tracing.
uint64_t trace_clock_base;
// Return value used by deoptimization.
JValue deoptimization_return_value;
RuntimeStats stats;
} tls64_;
struct PACKED(4) 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),
stack_trace_sample(nullptr), 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_return_value_stack(nullptr),
name(nullptr), pthread_self(0),
last_no_thread_suspension_cause(nullptr), thread_local_start(nullptr),
thread_local_pos(nullptr), thread_local_end(nullptr), thread_local_objects(0),
thread_local_alloc_stack_top(nullptr), thread_local_alloc_stack_end(nullptr),
nested_signal_state(nullptr), flip_function(nullptr), method_verifier(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;
// Pointer to previous stack trace captured by sampling profiler.
std::vector<ArtMethod*>* 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.
HandleScope* 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.
DeoptimizationReturnValueRecord* deoptimization_return_value_stack;
// 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. Installation guarding by
// Locks::thread_suspend_count_lock_.
Closure* checkpoint_functions[kMaxCheckpoints];
// Entrypoint function pointers.
// TODO: move this to more of a global offset table model to avoid per-thread duplication.
InterpreterEntryPoints interpreter_entrypoints;
JniEntryPoints jni_entrypoints;
QuickEntryPoints quick_entrypoints;
// Thread-local allocation pointer.
uint8_t* thread_local_start;
uint8_t* thread_local_pos;
uint8_t* thread_local_end;
size_t thread_local_objects;
// There are RosAlloc::kNumThreadLocalSizeBrackets thread-local size brackets per thread.
void* rosalloc_runs[kNumRosAllocThreadLocalSizeBrackets];
// 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];
// Recorded thread state for nested signals.
jmp_buf* nested_signal_state;
// The function used for thread flip.
Closure* flip_function;
// Current method verifier, used for root marking.
verifier::MethodVerifier* method_verifier;
} tlsPtr_;
// Guards the 'interrupted_' and '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_);
// Thread "interrupted" status; stays raised until queried or thrown.
bool interrupted_ GUARDED_BY(wait_mutex_);
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 ScopedAssertNoThreadSuspension {
ScopedAssertNoThreadSuspension(Thread* self, const char* cause)
: self_(self), old_cause_(self->StartAssertNoThreadSuspension(cause)) {
~ScopedAssertNoThreadSuspension() {
Thread* Self() {
return self_;
Thread* const self_;
const char* const 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_;
std::ostream& operator<<(std::ostream& os, const Thread& thread);
std::ostream& operator<<(std::ostream& os, const StackedShadowFrameType& thread);
} // namespace art