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* 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 <pthread.h>
#include <bitset>
#include <iosfwd>
#include <list>
#include <string>
#include <vector>
#include "dex_file.h"
#include "globals.h"
#include "jni_internal.h"
#include "logging.h"
#include "macros.h"
#include "mutex.h"
#include "mem_map.h"
#include "offsets.h"
#include "runtime_stats.h"
#include "stack.h"
#include "trace.h"
#include "UniquePtr.h"
namespace art {
class Array;
class Class;
class ClassLinker;
class ClassLoader;
class Context;
class DebugInvokeReq;
class Method;
class Monitor;
class Object;
class Runtime;
class ShadowFrame;
class StackIndirectReferenceTable;
class StackTraceElement;
class StaticStorageBase;
class Thread;
class ThreadList;
class Throwable;
template<class T> class ObjectArray;
template<class T> class PrimitiveArray;
typedef PrimitiveArray<int32_t> IntArray;
class PACKED Thread {
/* thread priorities, from java.lang.Thread */
enum Priority {
kMinPriority = 1,
kNormPriority = 5,
kMaxPriority = 10,
enum State {
// These correspond to JDWP states (but needn't share the same values).
kTerminated = 0, // TS_ZOMBIE
kRunnable = 1, // TS_RUNNING
kTimedWaiting = 2, // TS_WAIT in Object.wait() with a timeout
kBlocked = 3, // TS_MONITOR on a monitor
kWaiting = 4, // TS_WAIT in Object.wait()
// Non-JDWP states.
kInitializing = 5, // allocated, not yet running --- TODO: unnecessary?
kStarting = 6, // native thread started, not yet ready to run managed code
kNative = 7, // off in a JNI native method
kVmWait = 8, // waiting on a VM resource
kSuspended = 9, // suspended, usually by GC or debugger
// Space to throw a StackOverflowError in.
static const size_t kStackOverflowReservedBytes = 4 * KB;
static const size_t kDefaultStackSize = 96 * KB;
class StackVisitor {
virtual ~StackVisitor() {}
// Return 'true' if we should continue to visit more frames, 'false' to stop.
virtual bool VisitFrame(const Frame& frame, uintptr_t pc) = 0;
// Creates a new thread.
static void Create(Object* peer, size_t stack_size);
// Creates a new thread from the calling thread.
static Thread* Attach(const Runtime* runtime, const char* name, bool as_daemon);
// Reset internal state of child thread after fork.
void InitAfterFork();
static Thread* Current() {
void* thread = pthread_getspecific(Thread::pthread_key_self_);
return reinterpret_cast<Thread*>(thread);
static Thread* FromManagedThread(Object* thread_peer);
static Thread* FromManagedThread(JNIEnv* env, jobject thread);
static uint32_t LockOwnerFromThreadLock(Object* thread_lock);
// When full == true, dumps the detailed thread state and the thread stack (used for SIGQUIT).
// When full == false, dumps a one-line summary of thread state (used for operator<<).
void Dump(std::ostream& os, bool full = true) const;
State GetState() const {
return state_;
State SetState(State new_state);
void SetStateWithoutSuspendCheck(State new_state);
bool IsDaemon();
bool IsSuspended();
void WaitUntilSuspended();
bool HoldsLock(Object*);
* 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();
bool CanAccessDirectReferences() const {
// TODO: when we have a moving collector, we'll need: return state_ == kRunnable;
return true;
uint32_t GetThinLockId() const {
return thin_lock_id_;
pid_t GetTid() const {
return tid_;
// Returns the java.lang.Thread's name, or NULL if this Thread* doesn't have a peer.
String* GetThreadName() 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);
Object* GetPeer() const {
return peer_;
Object* GetThreadGroup() const;
RuntimeStats* GetStats() {
return &stats_;
int GetSuspendCount() const {
return suspend_count_;
// Returns the current Method* and native PC (not dex PC) for this thread.
Method* GetCurrentMethod(uintptr_t* pc = NULL, Method*** sp = NULL) const;
bool IsExceptionPending() const {
return exception_ != NULL;
Throwable* GetException() const {
return exception_;
void SetException(Throwable* new_exception) {
CHECK(new_exception != NULL);
// TODO: CHECK(exception_ == NULL);
exception_ = new_exception; // TODO
void ClearException() {
exception_ = NULL;
// Find catch block and perform long jump to appropriate exception handle
void DeliverException();
Context* GetLongJumpContext();
Frame GetTopOfStack() const {
return top_of_managed_stack_;
// TODO: this is here for testing, remove when we have exception unit tests
// that use the real stack
void SetTopOfStack(void* stack, uintptr_t pc) {
top_of_managed_stack_pc_ = pc;
void SetTopOfStackPC(uintptr_t pc) {
top_of_managed_stack_pc_ = pc;
// 'msg' may be NULL.
void ThrowNewException(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.
void ThrowOutOfMemoryError(const char* msg);
void ThrowOutOfMemoryError(Class* c, size_t byte_count);
Frame FindExceptionHandler(void* throw_pc, void** handler_pc);
void* FindExceptionHandlerInMethod(const Method* method,
void* throw_pc,
const DexFile& dex_file,
ClassLinker* class_linker);
static void Startup();
static void FinishStartup();
static void Shutdown();
// JNI methods
JNIEnvExt* GetJniEnv() const {
return jni_env_;
// Number of references allocated in SIRTs on this thread
size_t NumSirtReferences();
// Is the given obj in this thread's stack indirect reference table?
bool SirtContains(jobject obj);
void SirtVisitRoots(Heap::RootVisitor* visitor, void* arg);
void ShadowFrameVisitRoots(Heap::RootVisitor* visitor, void* arg);
// Convert a jobject into a Object*
Object* DecodeJObject(jobject obj);
// Implements java.lang.Thread.interrupted.
bool Interrupted() {
MutexLock mu(*wait_mutex_);
bool interrupted = interrupted_;
interrupted_ = false;
return interrupted;
// Implements java.lang.Thread.isInterrupted.
bool IsInterrupted() {
MutexLock mu(*wait_mutex_);
return interrupted_;
void Interrupt() {
MutexLock mu(*wait_mutex_);
if (interrupted_) {
interrupted_ = true;
void Notify() {
MutexLock mu(*wait_mutex_);
// Linked list recording transitions from native to managed code
void PushNativeToManagedRecord(NativeToManagedRecord* record);
void PopNativeToManagedRecord(const NativeToManagedRecord& record);
const ClassLoader* GetClassLoaderOverride() {
// TODO: need to place the class_loader_override_ in a handle
// DCHECK(CanAccessDirectReferences());
return class_loader_override_;
void SetClassLoaderOverride(const ClassLoader* class_loader_override) {
class_loader_override_ = class_loader_override;
// Create the internal representation of a stack trace, that is more time
// and space efficient to compute than the StackTraceElement[]
jobject CreateInternalStackTrace(JNIEnv* env) 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(JNIEnv* env, jobject internal,
jobjectArray output_array = NULL, int* stack_depth = NULL);
void VisitRoots(Heap::RootVisitor* visitor, void* arg);
// Offsets of various members of native Thread class, used by compiled code.
static ThreadOffset SelfOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, self_));
static ThreadOffset ExceptionOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, exception_));
static ThreadOffset ThinLockIdOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, thin_lock_id_));
static ThreadOffset CardTableOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, card_table_));
static ThreadOffset SuspendCountOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, suspend_count_));
static ThreadOffset StateOffset() {
return ThreadOffset(OFFSETOF_VOLATILE_MEMBER(Thread, state_));
// Size of stack less any space reserved for stack overflow
size_t GetStackSize() {
return stack_size_ - (stack_end_ - stack_begin_);
// Set the stack end to that to be used during a stack overflow
void SetStackEndForStackOverflow() {
// During stack overflow we allow use of the full stack
if (stack_end_ == stack_begin_) {
LOG(FATAL) << "Need to increase kStackOverflowReservedBytes (currently "
<< kStackOverflowReservedBytes << ")";
stack_end_ = stack_begin_;
// 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.
stack_end_ = stack_begin_ + kStackOverflowReservedBytes;
static ThreadOffset StackEndOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, stack_end_));
static ThreadOffset JniEnvOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, jni_env_));
static ThreadOffset TopOfManagedStackOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, top_of_managed_stack_) +
static ThreadOffset TopOfManagedStackPcOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, top_of_managed_stack_pc_));
void PushShadowFrame(ShadowFrame* frame);
ShadowFrame* PopShadowFrame();
void PushSirt(StackIndirectReferenceTable* sirt);
StackIndirectReferenceTable* PopSirt();
static ThreadOffset TopSirtOffset() {
return ThreadOffset(OFFSETOF_MEMBER(Thread, top_sirt_));
void WalkStack(StackVisitor* visitor, bool include_upcalls = false) const;
DebugInvokeReq* GetInvokeReq() {
return debug_invoke_req_;
bool IsTraceStackEmpty() const {
return trace_stack_->empty();
TraceStackFrame GetTraceStackFrame(uint32_t depth) const {
return trace_stack_->at(trace_stack_->size() - depth - 1);
void PushTraceStackFrame(const TraceStackFrame& frame) {
TraceStackFrame PopTraceStackFrame() {
TraceStackFrame frame = trace_stack_->back();
return frame;
void CheckSafeToLockOrUnlock(MutexRank rank, bool is_locking);
void CheckSafeToWait(MutexRank rank);
friend class ThreadList; // For ~Thread.
void CreatePeer(const char* name, bool as_daemon);
friend class Runtime; // For CreatePeer.
void DumpState(std::ostream& os) const;
void DumpStack(std::ostream& os) const;
void DumpNativeStack(std::ostream& os) const;
// Out-of-line conveniences for debugging in gdb.
static Thread* CurrentFromGdb(); // Like Thread::Current.
void DumpFromGdb() const; // Like Thread::Dump(std::cerr).
void Attach(const Runtime* runtime);
static void* CreateCallback(void* arg);
void HandleUncaughtExceptions();
void RemoveFromThreadGroup();
void InitCardTable();
void InitCpu();
void InitFunctionPointers();
void InitTid();
void InitPthreadKeySelf();
void InitStackHwm();
void NotifyLocked() {
if (wait_monitor_ != NULL) {
static void ThreadExitCallback(void* arg);
// 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_id_;
// System thread id.
pid_t tid_;
// Our managed peer (an instance of java.lang.Thread).
Object* peer_;
// The top_of_managed_stack_ and top_of_managed_stack_pc_ fields are accessed from
// compiled code, so we keep them early in the structure to (a) avoid having to keep
// fixing the assembler offsets and (b) improve the chances that these will still be aligned.
// Top of the managed stack, written out prior to the state transition from
// kRunnable to kNative. Uses include giving the starting point for scanning
// a managed stack when a thread is in native code.
Frame top_of_managed_stack_;
// PC corresponding to the call out of the top_of_managed_stack_ frame
uintptr_t top_of_managed_stack_pc_;
// Guards the 'interrupted_' and 'wait_monitor_' members.
mutable Mutex* wait_mutex_;
ConditionVariable* wait_cond_;
// Pointer to the monitor lock we're currently waiting on (or NULL), guarded by wait_mutex_.
Monitor* wait_monitor_;
// Thread "interrupted" status; stays raised until queried or thrown, guarded by wait_mutex_.
uint32_t interrupted_;
// The next thread in the wait set this thread is part of.
Thread* wait_next_;
// If we're blocked in MonitorEnter, this is the object we're trying to lock.
Object* monitor_enter_object_;
friend class Monitor;
RuntimeStats stats_;
// The biased card table, see CardTable for details
byte* card_table_;
// 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.
byte* stack_end_;
// Size of the stack
size_t stack_size_;
// The "lowest addressable byte" of the stack
byte* stack_begin_;
// A linked list (of stack allocated records) recording transitions from
// native to managed code.
NativeToManagedRecord* native_to_managed_record_;
// Top of linked list of stack indirect reference tables or NULL for none
StackIndirectReferenceTable* top_sirt_;
// Top of linked list of shadow stack or NULL for none
// Some backend may require shadow frame to ease the GC work.
ShadowFrame* top_shadow_frame_;
// Every thread may have an associated JNI environment
JNIEnvExt* jni_env_;
volatile State state_;
// 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_;
Runtime* runtime_;
// The pending exception or NULL.
Throwable* exception_;
// A non-zero value is used to tell the current thread to enter a safe point
// at the next poll.
int suspend_count_;
// 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_;
// Needed to get the right ClassLoader in JNI_OnLoad, but also
// useful for testing.
const ClassLoader* class_loader_override_;
// Thread local, lazily allocated, long jump context. Used to deliver exceptions.
Context* long_jump_context_;
// A boolean telling us whether we're recursively throwing OOME.
uint32_t throwing_OutOfMemoryError_;
Throwable* pre_allocated_OutOfMemoryError_;
// JDWP invoke-during-breakpoint support.
DebugInvokeReq* debug_invoke_req_;
// TLS key used to retrieve the VM thread object.
static pthread_key_t pthread_key_self_;
// Additional stack used by method tracer to store method and return pc values.
// Stored as a pointer since std::vector is not PACKED.
std::vector<TraceStackFrame>* trace_stack_;
// A cached copy of the java.lang.Thread's name.
std::string* name_;
uint32_t held_mutexes_[kMaxMutexRank + 1];
// Runtime support function pointers
void (*pDebugMe)(Method*, uint32_t);
void* (*pMemcpy)(void*, const void*, size_t);
uint64_t (*pShlLong)(uint64_t, uint32_t);
uint64_t (*pShrLong)(uint64_t, uint32_t);
uint64_t (*pUshrLong)(uint64_t, uint32_t);
float (*pI2f)(int);
int (*pF2iz)(float);
float (*pD2f)(double);
double (*pF2d)(float);
double (*pI2d)(int);
int (*pD2iz)(double);
float (*pL2f)(long);
double (*pL2d)(long);
long long (*pF2l)(float);
long long (*pD2l)(double);
float (*pFadd)(float, float);
float (*pFsub)(float, float);
float (*pFdiv)(float, float);
float (*pFmul)(float, float);
float (*pFmodf)(float, float);
double (*pDadd)(double, double);
double (*pDsub)(double, double);
double (*pDdiv)(double, double);
double (*pDmul)(double, double);
double (*pFmod)(double, double);
int (*pIdivmod)(int, int);
int (*pIdiv)(int, int);
long long (*pLmul)(long long, long long);
long long (*pLdivmod)(long long, long long);
void (*pCheckSuspendFromCode)(Thread*); // Stub that is called when the suspend count is non-zero
void (*pTestSuspendFromCode)(); // Stub that is periodically called to test the suspend count
void* (*pAllocObjectFromCode)(uint32_t, void*);
void* (*pAllocObjectFromCodeWithAccessCheck)(uint32_t, void*);
void* (*pAllocArrayFromCode)(uint32_t, void*, int32_t);
void* (*pAllocArrayFromCodeWithAccessCheck)(uint32_t, void*, int32_t);
void (*pCanPutArrayElementFromCode)(void*, void*);
void* (*pCheckAndAllocArrayFromCode)(uint32_t, void*, int32_t);
void* (*pCheckAndAllocArrayFromCodeWithAccessCheck)(uint32_t, void*, int32_t);
void (*pCheckCastFromCode)(void*, void*);
Object* (*pDecodeJObjectInThread)(Thread* thread, jobject obj);
void (*pDeliverException)(void*);
Method* (*pFindInterfaceMethodInCache)(Class*, uint32_t, const Method*, struct DvmDex*);
void* (*pFindNativeMethod)(Thread* thread);
int32_t (*pGet32Instance)(uint32_t, void*);
int64_t (*pGet64Instance)(uint32_t, void*);
void* (*pGetObjInstance)(uint32_t, void*);
int32_t (*pGet32Static)(uint32_t);
int64_t (*pGet64Static)(uint32_t);
void* (*pGetObjStatic)(uint32_t);
void (*pHandleFillArrayDataFromCode)(void*, void*);
void* (*pInitializeStaticStorage)(uint32_t, void*);
uint32_t (*pInstanceofNonTrivialFromCode)(const Class*, const Class*);
void (*pInvokeDirectTrampolineWithAccessCheck)(uint32_t, void*);
void (*pInvokeInterfaceTrampoline)(uint32_t, void*);
void (*pInvokeInterfaceTrampolineWithAccessCheck)(uint32_t, void*);
void (*pInvokeStaticTrampolineWithAccessCheck)(uint32_t, void*);
void (*pInvokeSuperTrampolineWithAccessCheck)(uint32_t, void*);
void (*pInvokeVirtualTrampolineWithAccessCheck)(uint32_t, void*);
void* (*pInitializeTypeFromCode)(uint32_t, void*);
void* (*pInitializeTypeAndVerifyAccessFromCode)(uint32_t, void*);
void (*pLockObjectFromCode)(void*);
void* (*pResolveStringFromCode)(void*, uint32_t);
int (*pSet32Instance)(uint32_t, void*, int32_t); // field_idx, obj, src
int (*pSet64Instance)(uint32_t, void*, int64_t);
int (*pSetObjInstance)(uint32_t, void*, void*);
int (*pSet32Static)(uint32_t, int32_t);
int (*pSet64Static)(uint32_t, int64_t);
int (*pSetObjStatic)(uint32_t, void*);
void (*pThrowStackOverflowFromCode)(void*);
void (*pThrowNullPointerFromCode)();
void (*pThrowArrayBoundsFromCode)(int32_t, int32_t);
void (*pThrowDivZeroFromCode)();
void (*pThrowVerificationErrorFromCode)(int32_t, int32_t);
void (*pThrowNegArraySizeFromCode)(int32_t);
void (*pThrowNoSuchMethodFromCode)(int32_t);
void (*pThrowAbstractMethodErrorFromCode)(Method* method, Thread* thread, Method** sp);
void (*pUnlockObjectFromCode)(void*);
const void* (*pUnresolvedDirectMethodTrampolineFromCode)(Method*, Method**, Thread*,
void (*pUpdateDebuggerFromCode)(void*, void*, int32_t, void*);
bool (*pCmplFloat)(float, float);
bool (*pCmpgFloat)(float, float);
bool (*pCmplDouble)(double, double);
bool (*pCmpgDouble)(double, double);
std::ostream& operator<<(std::ostream& os, const Thread& thread);
std::ostream& operator<<(std::ostream& os, const Thread::State& state);
class ScopedThreadStateChange {
ScopedThreadStateChange(Thread* thread, Thread::State new_state) : thread_(thread) {
old_thread_state_ = thread_->SetState(new_state);
~ScopedThreadStateChange() {
Thread* thread_;
Thread::State old_thread_state_;
} // namespace art
#endif // ART_SRC_THREAD_H_