blob: e997723e5eef6dbd7906774ce74c5787d544941d [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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "thread.h"
#include <dynamic_annotations.h>
#include <pthread.h>
#include <sys/mman.h>
#include <algorithm>
#include <bitset>
#include <cerrno>
#include <iostream>
#include <list>
#include "class_linker.h"
#include "compiler.h"
#include "context.h"
#include "dex_verifier.h"
#include "heap.h"
#include "jni_internal.h"
#include "monitor.h"
#include "object.h"
#include "runtime.h"
#include "runtime_support.h"
#include "scoped_jni_thread_state.h"
#include "thread_list.h"
#include "utils.h"
namespace art {
pthread_key_t Thread::pthread_key_self_;
static Class* gThreadLock = NULL;
static Class* gThrowable = NULL;
static Field* gThread_daemon = NULL;
static Field* gThread_group = NULL;
static Field* gThread_lock = NULL;
static Field* gThread_name = NULL;
static Field* gThread_priority = NULL;
static Field* gThread_uncaughtHandler = NULL;
static Field* gThread_vmData = NULL;
static Field* gThreadGroup_name = NULL;
static Field* gThreadLock_thread = NULL;
static Method* gThread_run = NULL;
static Method* gThreadGroup_removeThread = NULL;
static Method* gUncaughtExceptionHandler_uncaughtException = NULL;
void Thread::InitFunctionPointers() {
#if defined(__arm__)
pShlLong = art_shl_long;
pShrLong = art_shr_long;
pUshrLong = art_ushr_long;
pIdiv = __aeabi_idiv;
pIdivmod = __aeabi_idivmod;
pI2f = __aeabi_i2f;
pF2iz = __aeabi_f2iz;
pD2f = __aeabi_d2f;
pF2d = __aeabi_f2d;
pD2iz = __aeabi_d2iz;
pL2f = __aeabi_l2f;
pL2d = __aeabi_l2d;
pFadd = __aeabi_fadd;
pFsub = __aeabi_fsub;
pFdiv = __aeabi_fdiv;
pFmul = __aeabi_fmul;
pFmodf = fmodf;
pDadd = __aeabi_dadd;
pDsub = __aeabi_dsub;
pDdiv = __aeabi_ddiv;
pDmul = __aeabi_dmul;
pFmod = fmod;
pLdivmod = __aeabi_ldivmod;
pLmul = __aeabi_lmul;
pAllocObjectFromCode = art_alloc_object_from_code;
pArrayAllocFromCode = art_array_alloc_from_code;
pCanPutArrayElementFromCode = art_can_put_array_element_from_code;
pCheckAndArrayAllocFromCode = art_check_and_array_alloc_from_code;
pCheckCastFromCode = art_check_cast_from_code;
pHandleFillArrayDataFromCode = art_handle_fill_data_from_code;
pInitializeStaticStorage = art_initialize_static_storage_from_code;
pInvokeInterfaceTrampoline = art_invoke_interface_trampoline;
pTestSuspendFromCode = art_test_suspend;
pThrowArrayBoundsFromCode = art_throw_array_bounds_from_code;
pThrowDivZeroFromCode = art_throw_div_zero_from_code;
pThrowInternalErrorFromCode = art_throw_internal_error_from_code;
pThrowNegArraySizeFromCode = art_throw_neg_array_size_from_code;
pThrowNoSuchMethodFromCode = art_throw_no_such_method_from_code;
pThrowNullPointerFromCode = art_throw_null_pointer_exception_from_code;
pThrowRuntimeExceptionFromCode = art_throw_runtime_exception_from_code;
pThrowStackOverflowFromCode = art_throw_stack_overflow_from_code;
pThrowVerificationErrorFromCode = art_throw_verification_error_from_code;
pUnlockObjectFromCode = art_unlock_object_from_code;
#endif
pDeliverException = art_deliver_exception_from_code;
pThrowAbstractMethodErrorFromCode = ThrowAbstractMethodErrorFromCode;
pF2l = F2L;
pD2l = D2L;
pMemcpy = memcpy;
pGet32Static = Field::Get32StaticFromCode;
pSet32Static = Field::Set32StaticFromCode;
pGet64Static = Field::Get64StaticFromCode;
pSet64Static = Field::Set64StaticFromCode;
pGetObjStatic = Field::GetObjStaticFromCode;
pSetObjStatic = Field::SetObjStaticFromCode;
pInitializeTypeFromCode = InitializeTypeFromCode;
pResolveMethodFromCode = ResolveMethodFromCode;
pInstanceofNonTrivialFromCode = Class::IsAssignableFromCode;
pLockObjectFromCode = LockObjectFromCode;
pFindInstanceFieldFromCode = Field::FindInstanceFieldFromCode;
pCheckSuspendFromCode = artCheckSuspendFromCode;
pFindNativeMethod = FindNativeMethod;
pDecodeJObjectInThread = DecodeJObjectInThread;
pDebugMe = DebugMe;
}
void Frame::Next() {
size_t frame_size = GetMethod()->GetFrameSizeInBytes();
DCHECK_NE(frame_size, 0u);
DCHECK_LT(frame_size, 1024u);
byte* next_sp = reinterpret_cast<byte*>(sp_) + frame_size;
sp_ = reinterpret_cast<Method**>(next_sp);
if (*sp_ != NULL) {
DCHECK((*sp_)->GetClass() == Method::GetMethodClass() ||
(*sp_)->GetClass() == Method::GetConstructorClass());
}
}
bool Frame::HasMethod() const {
return GetMethod() != NULL && (!GetMethod()->IsPhony());
}
uintptr_t Frame::GetReturnPC() const {
byte* pc_addr = reinterpret_cast<byte*>(sp_) + GetMethod()->GetReturnPcOffsetInBytes();
return *reinterpret_cast<uintptr_t*>(pc_addr);
}
uintptr_t Frame::GetVReg(Method* method, int vreg) const {
DCHECK(method == GetMethod());
int offset = oatVRegOffsetFromMethod(method, vreg);
byte* vreg_addr = reinterpret_cast<byte*>(sp_) + offset;
return *reinterpret_cast<uintptr_t*>(vreg_addr);
}
uintptr_t Frame::LoadCalleeSave(int num) const {
// Callee saves are held at the top of the frame
Method* method = GetMethod();
DCHECK(method != NULL);
size_t frame_size = method->GetFrameSizeInBytes();
byte* save_addr = reinterpret_cast<byte*>(sp_) + frame_size - ((num + 1) * kPointerSize);
#if defined(__i386__)
save_addr -= kPointerSize; // account for return address
#endif
return *reinterpret_cast<uintptr_t*>(save_addr);
}
Method* Frame::NextMethod() const {
byte* next_sp = reinterpret_cast<byte*>(sp_) +
GetMethod()->GetFrameSizeInBytes();
return *reinterpret_cast<Method**>(next_sp);
}
void* Thread::CreateCallback(void* arg) {
Thread* self = reinterpret_cast<Thread*>(arg);
Runtime* runtime = Runtime::Current();
self->Attach(runtime);
String* thread_name = reinterpret_cast<String*>(gThread_name->GetObject(self->peer_));
if (thread_name != NULL) {
SetThreadName(thread_name->ToModifiedUtf8().c_str());
}
// Wait until it's safe to start running code. (There may have been a suspend-all
// in progress while we were starting up.)
runtime->GetThreadList()->WaitForGo();
// TODO: say "hi" to the debugger.
//if (gDvm.debuggerConnected) {
// dvmDbgPostThreadStart(self);
//}
// Invoke the 'run' method of our java.lang.Thread.
CHECK(self->peer_ != NULL);
Object* receiver = self->peer_;
Method* m = receiver->GetClass()->FindVirtualMethodForVirtualOrInterface(gThread_run);
m->Invoke(self, receiver, NULL, NULL);
// Detach.
runtime->GetThreadList()->Unregister();
return NULL;
}
void SetVmData(Object* managed_thread, Thread* native_thread) {
gThread_vmData->SetInt(managed_thread, reinterpret_cast<uintptr_t>(native_thread));
}
Thread* Thread::FromManagedThread(JNIEnv* env, jobject java_thread) {
Object* thread = Decode<Object*>(env, java_thread);
return reinterpret_cast<Thread*>(static_cast<uintptr_t>(gThread_vmData->GetInt(thread)));
}
size_t FixStackSize(size_t stack_size) {
// A stack size of zero means "use the default".
if (stack_size == 0) {
stack_size = Runtime::Current()->GetDefaultStackSize();
}
// It's not possible to request a stack smaller than the system-defined PTHREAD_STACK_MIN.
if (stack_size < PTHREAD_STACK_MIN) {
stack_size = PTHREAD_STACK_MIN;
}
// It's likely that callers are trying to ensure they have at least a certain amount of
// stack space, so we should add our reserved space on top of what they requested, rather
// than implicitly take it away from them.
stack_size += Thread::kStackOverflowReservedBytes;
// Some systems require the stack size to be a multiple of the system page size, so round up.
stack_size = RoundUp(stack_size, kPageSize);
return stack_size;
}
void Thread::Create(Object* peer, size_t stack_size) {
CHECK(peer != NULL);
stack_size = FixStackSize(stack_size);
Thread* native_thread = new Thread;
native_thread->peer_ = peer;
// Thread.start is synchronized, so we know that vmData is 0,
// and know that we're not racing to assign it.
SetVmData(peer, native_thread);
pthread_attr_t attr;
CHECK_PTHREAD_CALL(pthread_attr_init, (&attr), "new thread");
CHECK_PTHREAD_CALL(pthread_attr_setdetachstate, (&attr, PTHREAD_CREATE_DETACHED), "PTHREAD_CREATE_DETACHED");
CHECK_PTHREAD_CALL(pthread_attr_setstacksize, (&attr, stack_size), stack_size);
CHECK_PTHREAD_CALL(pthread_create, (&native_thread->pthread_, &attr, Thread::CreateCallback, native_thread), "new thread");
CHECK_PTHREAD_CALL(pthread_attr_destroy, (&attr), "new thread");
// Let the child know when it's safe to start running.
Runtime::Current()->GetThreadList()->SignalGo(native_thread);
}
void Thread::Attach(const Runtime* runtime) {
InitCpu();
InitFunctionPointers();
thin_lock_id_ = Runtime::Current()->GetThreadList()->AllocThreadId();
tid_ = ::art::GetTid();
pthread_ = pthread_self();
InitStackHwm();
CHECK_PTHREAD_CALL(pthread_setspecific, (Thread::pthread_key_self_, this), "attach");
jni_env_ = new JNIEnvExt(this, runtime->GetJavaVM());
runtime->GetThreadList()->Register();
}
Thread* Thread::Attach(const Runtime* runtime, const char* name, bool as_daemon) {
Thread* self = new Thread;
self->Attach(runtime);
self->SetState(Thread::kNative);
SetThreadName(name);
// If we're the main thread, ClassLinker won't be created until after we're attached,
// so that thread needs a two-stage attach. Regular threads don't need this hack.
if (self->thin_lock_id_ != ThreadList::kMainId) {
self->CreatePeer(name, as_daemon);
}
return self;
}
jobject GetWellKnownThreadGroup(JNIEnv* env, const char* field_name) {
jclass thread_group_class = env->FindClass("java/lang/ThreadGroup");
jfieldID fid = env->GetStaticFieldID(thread_group_class, field_name, "Ljava/lang/ThreadGroup;");
jobject thread_group = env->GetStaticObjectField(thread_group_class, fid);
// This will be null in the compiler (and tests), but never in a running system.
//CHECK(thread_group != NULL) << "java.lang.ThreadGroup." << field_name << " not initialized";
return thread_group;
}
void Thread::CreatePeer(const char* name, bool as_daemon) {
JNIEnv* env = jni_env_;
const char* field_name = (GetThinLockId() == ThreadList::kMainId) ? "mMain" : "mSystem";
jobject thread_group = GetWellKnownThreadGroup(env, field_name);
jobject thread_name = env->NewStringUTF(name);
jint thread_priority = GetNativePriority();
jboolean thread_is_daemon = as_daemon;
jclass c = env->FindClass("java/lang/Thread");
jmethodID mid = env->GetMethodID(c, "<init>", "(Ljava/lang/ThreadGroup;Ljava/lang/String;IZ)V");
jobject peer = env->NewObject(c, mid, thread_group, thread_name, thread_priority, thread_is_daemon);
peer_ = DecodeJObject(peer);
SetVmData(peer_, Thread::Current());
// Because we mostly run without code available (in the compiler, in tests), we
// manually assign the fields the constructor should have set.
// TODO: lose this.
gThread_daemon->SetBoolean(peer_, thread_is_daemon);
gThread_group->SetObject(peer_, Decode<Object*>(env, thread_group));
gThread_name->SetObject(peer_, Decode<Object*>(env, thread_name));
gThread_priority->SetInt(peer_, thread_priority);
}
void Thread::InitStackHwm() {
pthread_attr_t attributes;
CHECK_PTHREAD_CALL(pthread_getattr_np, (pthread_, &attributes), __FUNCTION__);
void* temp_stack_base;
CHECK_PTHREAD_CALL(pthread_attr_getstack, (&attributes, &temp_stack_base, &stack_size_),
__FUNCTION__);
stack_base_ = reinterpret_cast<byte*>(temp_stack_base);
if (stack_size_ <= kStackOverflowReservedBytes) {
LOG(FATAL) << "attempt to attach a thread with a too-small stack (" << stack_size_ << " bytes)";
}
// Set stack_end_ to the bottom of the stack saving space of stack overflows
ResetDefaultStackEnd();
// Sanity check.
int stack_variable;
CHECK_GT(&stack_variable, (void*) stack_end_);
CHECK_PTHREAD_CALL(pthread_attr_destroy, (&attributes), __FUNCTION__);
}
void Thread::Dump(std::ostream& os) const {
DumpState(os);
DumpStack(os);
}
std::string GetSchedulerGroup(pid_t tid) {
// /proc/<pid>/group looks like this:
// 2:devices:/
// 1:cpuacct,cpu:/
// We want the third field from the line whose second field contains the "cpu" token.
std::string cgroup_file;
if (!ReadFileToString("/proc/self/cgroup", &cgroup_file)) {
return "";
}
std::vector<std::string> cgroup_lines;
Split(cgroup_file, '\n', cgroup_lines);
for (size_t i = 0; i < cgroup_lines.size(); ++i) {
std::vector<std::string> cgroup_fields;
Split(cgroup_lines[i], ':', cgroup_fields);
std::vector<std::string> cgroups;
Split(cgroup_fields[1], ',', cgroups);
for (size_t i = 0; i < cgroups.size(); ++i) {
if (cgroups[i] == "cpu") {
return cgroup_fields[2].substr(1); // Skip the leading slash.
}
}
}
return "";
}
void Thread::DumpState(std::ostream& os) const {
std::string thread_name("<native thread without managed peer>");
std::string group_name;
int priority;
bool is_daemon = false;
if (peer_ != NULL) {
String* thread_name_string = reinterpret_cast<String*>(gThread_name->GetObject(peer_));
thread_name = (thread_name_string != NULL) ? thread_name_string->ToModifiedUtf8() : "<null>";
priority = gThread_priority->GetInt(peer_);
is_daemon = gThread_daemon->GetBoolean(peer_);
Object* thread_group = gThread_group->GetObject(peer_);
if (thread_group != NULL) {
String* group_name_string = reinterpret_cast<String*>(gThreadGroup_name->GetObject(thread_group));
group_name = (group_name_string != NULL) ? group_name_string->ToModifiedUtf8() : "<null>";
}
} else {
// This name may be truncated, but it's the best we can do in the absence of a managed peer.
std::string stats;
if (ReadFileToString(StringPrintf("/proc/self/task/%d/stat", GetTid()).c_str(), &stats)) {
size_t start = stats.find('(') + 1;
size_t end = stats.find(')') - start;
thread_name = stats.substr(start, end);
}
priority = GetNativePriority();
}
int policy;
sched_param sp;
CHECK_PTHREAD_CALL(pthread_getschedparam, (pthread_, &policy, &sp), __FUNCTION__);
std::string scheduler_group(GetSchedulerGroup(GetTid()));
if (scheduler_group.empty()) {
scheduler_group = "default";
}
os << '"' << thread_name << '"';
if (is_daemon) {
os << " daemon";
}
os << " prio=" << priority
<< " tid=" << GetThinLockId()
<< " " << GetState() << "\n";
int debug_suspend_count = 0; // TODO
os << " | group=\"" << group_name << "\""
<< " sCount=" << suspend_count_
<< " dsCount=" << debug_suspend_count
<< " obj=" << reinterpret_cast<void*>(peer_)
<< " self=" << reinterpret_cast<const void*>(this) << "\n";
os << " | sysTid=" << GetTid()
<< " nice=" << getpriority(PRIO_PROCESS, GetTid())
<< " sched=" << policy << "/" << sp.sched_priority
<< " cgrp=" << scheduler_group
<< " handle=" << GetImpl() << "\n";
// Grab the scheduler stats for this thread.
std::string scheduler_stats;
if (ReadFileToString(StringPrintf("/proc/self/task/%d/schedstat", GetTid()).c_str(), &scheduler_stats)) {
scheduler_stats.resize(scheduler_stats.size() - 1); // Lose the trailing '\n'.
} else {
scheduler_stats = "0 0 0";
}
int utime = 0;
int stime = 0;
int task_cpu = 0;
std::string stats;
if (ReadFileToString(StringPrintf("/proc/self/task/%d/stat", GetTid()).c_str(), &stats)) {
// Skip the command, which may contain spaces.
stats = stats.substr(stats.find(')') + 2);
// Extract the three fields we care about.
std::vector<std::string> fields;
Split(stats, ' ', fields);
utime = strtoull(fields[11].c_str(), NULL, 10);
stime = strtoull(fields[12].c_str(), NULL, 10);
task_cpu = strtoull(fields[36].c_str(), NULL, 10);
}
os << " | schedstat=( " << scheduler_stats << " )"
<< " utm=" << utime
<< " stm=" << stime
<< " core=" << task_cpu
<< " HZ=" << sysconf(_SC_CLK_TCK) << "\n";
}
struct StackDumpVisitor : public Thread::StackVisitor {
StackDumpVisitor(std::ostream& os, const Thread* thread)
: os(os), thread(thread), frame_count(0) {
}
virtual ~StackDumpVisitor() {
}
void VisitFrame(const Frame& frame, uintptr_t pc) {
if (!frame.HasMethod()) {
return;
}
Method* m = frame.GetMethod();
Class* c = m->GetDeclaringClass();
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
const DexFile& dex_file = class_linker->FindDexFile(c->GetDexCache());
os << " at " << PrettyMethod(m, false);
if (m->IsNative()) {
os << "(Native method)";
} else {
int line_number = dex_file.GetLineNumFromPC(m, m->ToDexPC(pc));
os << "(" << c->GetSourceFile()->ToModifiedUtf8() << ":" << line_number << ")";
}
os << "\n";
if (frame_count++ == 0) {
Monitor::DescribeWait(os, thread);
}
}
std::ostream& os;
const Thread* thread;
int frame_count;
};
void Thread::DumpStack(std::ostream& os) const {
StackDumpVisitor dumper(os, this);
WalkStack(&dumper);
}
Thread::State Thread::SetState(Thread::State new_state) {
Thread::State old_state = state_;
if (old_state == new_state) {
return old_state;
}
volatile void* raw = reinterpret_cast<volatile void*>(&state_);
volatile int32_t* addr = reinterpret_cast<volatile int32_t*>(raw);
if (new_state == Thread::kRunnable) {
/*
* Change our status to Thread::kRunnable. The transition requires
* that we check for pending suspension, because the VM considers
* us to be "asleep" in all other states, and another thread could
* be performing a GC now.
*
* The order of operations is very significant here. One way to
* do this wrong is:
*
* GCing thread Our thread (in kNative)
* ------------ ----------------------
* check suspend count (== 0)
* SuspendAllThreads()
* grab suspend-count lock
* increment all suspend counts
* release suspend-count lock
* check thread state (== kNative)
* all are suspended, begin GC
* set state to kRunnable
* (continue executing)
*
* We can correct this by grabbing the suspend-count lock and
* performing both of our operations (check suspend count, set
* state) while holding it, now we need to grab a mutex on every
* transition to kRunnable.
*
* What we do instead is change the order of operations so that
* the transition to kRunnable happens first. If we then detect
* that the suspend count is nonzero, we switch to kSuspended.
*
* Appropriate compiler and memory barriers are required to ensure
* that the operations are observed in the expected order.
*
* This does create a small window of opportunity where a GC in
* progress could observe what appears to be a running thread (if
* it happens to look between when we set to kRunnable and when we
* switch to kSuspended). At worst this only affects assertions
* and thread logging. (We could work around it with some sort
* of intermediate "pre-running" state that is generally treated
* as equivalent to running, but that doesn't seem worthwhile.)
*
* We can also solve this by combining the "status" and "suspend
* count" fields into a single 32-bit value. This trades the
* store/load barrier on transition to kRunnable for an atomic RMW
* op on all transitions and all suspend count updates (also, all
* accesses to status or the thread count require bit-fiddling).
* It also eliminates the brief transition through kRunnable when
* the thread is supposed to be suspended. This is possibly faster
* on SMP and slightly more correct, but less convenient.
*/
android_atomic_acquire_store(new_state, addr);
if (ANNOTATE_UNPROTECTED_READ(suspend_count_) != 0) {
Runtime::Current()->GetThreadList()->FullSuspendCheck(this);
}
} else {
/*
* Not changing to Thread::kRunnable. No additional work required.
*
* We use a releasing store to ensure that, if we were runnable,
* any updates we previously made to objects on the managed heap
* will be observed before the state change.
*/
android_atomic_release_store(new_state, addr);
}
return old_state;
}
void Thread::WaitUntilSuspended() {
// TODO: dalvik dropped the waiting thread's priority after a while.
// TODO: dalvik timed out and aborted.
useconds_t delay = 0;
while (GetState() == Thread::kRunnable) {
useconds_t new_delay = delay * 2;
CHECK_GE(new_delay, delay);
delay = new_delay;
if (delay == 0) {
sched_yield();
delay = 10000;
} else {
usleep(delay);
}
}
}
void Thread::ThreadExitCallback(void* arg) {
Thread* self = reinterpret_cast<Thread*>(arg);
LOG(FATAL) << "Native thread exited without calling DetachCurrentThread: " << *self;
}
void Thread::Startup() {
// Allocate a TLS slot.
CHECK_PTHREAD_CALL(pthread_key_create, (&Thread::pthread_key_self_, Thread::ThreadExitCallback), "self key");
// Double-check the TLS slot allocation.
if (pthread_getspecific(pthread_key_self_) != NULL) {
LOG(FATAL) << "newly-created pthread TLS slot is not NULL";
}
}
// TODO: make more accessible?
Class* FindPrimitiveClassOrDie(ClassLinker* class_linker, char descriptor) {
Class* c = class_linker->FindPrimitiveClass(descriptor);
CHECK(c != NULL) << descriptor;
return c;
}
// TODO: make more accessible?
Class* FindClassOrDie(ClassLinker* class_linker, const char* descriptor) {
Class* c = class_linker->FindSystemClass(descriptor);
CHECK(c != NULL) << descriptor;
return c;
}
// TODO: make more accessible?
Field* FindFieldOrDie(Class* c, const char* name, Class* type) {
Field* f = c->FindDeclaredInstanceField(name, type);
CHECK(f != NULL) << PrettyClass(c) << " " << name << " " << PrettyClass(type);
return f;
}
// TODO: make more accessible?
Method* FindMethodOrDie(Class* c, const char* name, const char* signature) {
Method* m = c->FindVirtualMethod(name, signature);
CHECK(m != NULL) << PrettyClass(c) << " " << name << " " << signature;
return m;
}
void Thread::FinishStartup() {
// Now the ClassLinker is ready, we can find the various Class*, Field*, and Method*s we need.
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
Class* boolean_class = FindPrimitiveClassOrDie(class_linker, 'Z');
Class* int_class = FindPrimitiveClassOrDie(class_linker, 'I');
Class* String_class = FindClassOrDie(class_linker, "Ljava/lang/String;");
Class* Thread_class = FindClassOrDie(class_linker, "Ljava/lang/Thread;");
Class* ThreadGroup_class = FindClassOrDie(class_linker, "Ljava/lang/ThreadGroup;");
Class* UncaughtExceptionHandler_class = FindClassOrDie(class_linker, "Ljava/lang/Thread$UncaughtExceptionHandler;");
gThreadLock = FindClassOrDie(class_linker, "Ljava/lang/ThreadLock;");
gThrowable = FindClassOrDie(class_linker, "Ljava/lang/Throwable;");
gThread_daemon = FindFieldOrDie(Thread_class, "daemon", boolean_class);
gThread_group = FindFieldOrDie(Thread_class, "group", ThreadGroup_class);
gThread_lock = FindFieldOrDie(Thread_class, "lock", gThreadLock);
gThread_name = FindFieldOrDie(Thread_class, "name", String_class);
gThread_priority = FindFieldOrDie(Thread_class, "priority", int_class);
gThread_uncaughtHandler = FindFieldOrDie(Thread_class, "uncaughtHandler", UncaughtExceptionHandler_class);
gThread_vmData = FindFieldOrDie(Thread_class, "vmData", int_class);
gThreadGroup_name = FindFieldOrDie(ThreadGroup_class, "name", String_class);
gThreadLock_thread = FindFieldOrDie(gThreadLock, "thread", Thread_class);
gThread_run = FindMethodOrDie(Thread_class, "run", "()V");
gThreadGroup_removeThread = FindMethodOrDie(ThreadGroup_class, "removeThread", "(Ljava/lang/Thread;)V");
gUncaughtExceptionHandler_uncaughtException = FindMethodOrDie(UncaughtExceptionHandler_class,
"uncaughtException", "(Ljava/lang/Thread;Ljava/lang/Throwable;)V");
// Finish attaching the main thread.
Thread::Current()->CreatePeer("main", false);
}
void Thread::Shutdown() {
CHECK_PTHREAD_CALL(pthread_key_delete, (Thread::pthread_key_self_), "self key");
}
uint32_t Thread::LockOwnerFromThreadLock(Object* thread_lock) {
if (thread_lock == NULL || thread_lock->GetClass() != gThreadLock) {
return ThreadList::kInvalidId;
}
Object* managed_thread = gThreadLock_thread->GetObject(thread_lock);
if (managed_thread == NULL) {
return ThreadList::kInvalidId;
}
uintptr_t vmData = static_cast<uintptr_t>(gThread_vmData->GetInt(managed_thread));
Thread* thread = reinterpret_cast<Thread*>(vmData);
if (thread == NULL) {
return ThreadList::kInvalidId;
}
return thread->GetThinLockId();
}
Thread::Thread()
: peer_(NULL),
top_of_managed_stack_(),
top_of_managed_stack_pc_(0),
wait_mutex_(new Mutex("Thread wait mutex")),
wait_cond_(new ConditionVariable("Thread wait condition variable")),
wait_monitor_(NULL),
interrupted_(false),
wait_next_(NULL),
monitor_enter_object_(NULL),
card_table_(0),
stack_end_(NULL),
native_to_managed_record_(NULL),
top_sirt_(NULL),
jni_env_(NULL),
state_(Thread::kNative),
self_(NULL),
runtime_(NULL),
exception_(NULL),
suspend_count_(0),
class_loader_override_(NULL),
long_jump_context_(NULL) {
CHECK((sizeof(Thread) % 4) == 0) << sizeof(Thread);
}
void MonitorExitVisitor(const Object* object, void*) {
Object* entered_monitor = const_cast<Object*>(object);
entered_monitor->MonitorExit(Thread::Current());
}
Thread::~Thread() {
SetState(Thread::kRunnable);
// On thread detach, all monitors entered with JNI MonitorEnter are automatically exited.
if (jni_env_ != NULL) {
jni_env_->monitors.VisitRoots(MonitorExitVisitor, NULL);
}
if (peer_ != NULL) {
Object* group = gThread_group->GetObject(peer_);
// Handle any pending exception.
if (IsExceptionPending()) {
// Get and clear the exception.
Object* exception = GetException();
ClearException();
// If the thread has its own handler, use that.
Object* handler = gThread_uncaughtHandler->GetObject(peer_);
if (handler == NULL) {
// Otherwise use the thread group's default handler.
handler = group;
}
// Call the handler.
Method* m = handler->GetClass()->FindVirtualMethodForVirtualOrInterface(gUncaughtExceptionHandler_uncaughtException);
Object* args[2];
args[0] = peer_;
args[1] = exception;
m->Invoke(this, handler, reinterpret_cast<byte*>(&args), NULL);
// If the handler threw, clear that exception too.
ClearException();
}
// this.group.removeThread(this);
// group can be null if we're in the compiler or a test.
if (group != NULL) {
Method* m = group->GetClass()->FindVirtualMethodForVirtualOrInterface(gThreadGroup_removeThread);
Object* args = peer_;
m->Invoke(this, group, reinterpret_cast<byte*>(&args), NULL);
}
// this.vmData = 0;
SetVmData(peer_, NULL);
// TODO: say "bye" to the debugger.
//if (gDvm.debuggerConnected) {
// dvmDbgPostThreadDeath(self);
//}
// Thread.join() is implemented as an Object.wait() on the Thread.lock
// object. Signal anyone who is waiting.
Thread* self = Thread::Current();
Object* lock = gThread_lock->GetObject(peer_);
// (This conditional is only needed for tests, where Thread.lock won't have been set.)
if (lock != NULL) {
lock->MonitorEnter(self);
lock->NotifyAll();
lock->MonitorExit(self);
}
}
delete jni_env_;
jni_env_ = NULL;
SetState(Thread::kTerminated);
delete wait_cond_;
delete wait_mutex_;
delete long_jump_context_;
}
size_t Thread::NumSirtReferences() {
size_t count = 0;
for (StackIndirectReferenceTable* cur = top_sirt_; cur; cur = cur->Link()) {
count += cur->NumberOfReferences();
}
return count;
}
bool Thread::SirtContains(jobject obj) {
Object** sirt_entry = reinterpret_cast<Object**>(obj);
for (StackIndirectReferenceTable* cur = top_sirt_; cur; cur = cur->Link()) {
size_t num_refs = cur->NumberOfReferences();
// A SIRT should always have a jobject/jclass as a native method is passed
// in a this pointer or a class
DCHECK_GT(num_refs, 0u);
if ((&cur->References()[0] <= sirt_entry) &&
(sirt_entry <= (&cur->References()[num_refs - 1]))) {
return true;
}
}
return false;
}
void Thread::SirtVisitRoots(Heap::RootVisitor* visitor, void* arg) {
for (StackIndirectReferenceTable* cur = top_sirt_; cur; cur = cur->Link()) {
size_t num_refs = cur->NumberOfReferences();
for (size_t j = 0; j < num_refs; j++) {
visitor(cur->References()[j], arg);
}
}
}
void Thread::PopSirt() {
CHECK(top_sirt_ != NULL);
top_sirt_ = top_sirt_->Link();
}
Object* Thread::DecodeJObject(jobject obj) {
DCHECK(CanAccessDirectReferences());
if (obj == NULL) {
return NULL;
}
IndirectRef ref = reinterpret_cast<IndirectRef>(obj);
IndirectRefKind kind = GetIndirectRefKind(ref);
Object* result;
switch (kind) {
case kLocal:
{
IndirectReferenceTable& locals = jni_env_->locals;
result = const_cast<Object*>(locals.Get(ref));
break;
}
case kGlobal:
{
JavaVMExt* vm = Runtime::Current()->GetJavaVM();
IndirectReferenceTable& globals = vm->globals;
MutexLock mu(vm->globals_lock);
result = const_cast<Object*>(globals.Get(ref));
break;
}
case kWeakGlobal:
{
JavaVMExt* vm = Runtime::Current()->GetJavaVM();
IndirectReferenceTable& weak_globals = vm->weak_globals;
MutexLock mu(vm->weak_globals_lock);
result = const_cast<Object*>(weak_globals.Get(ref));
if (result == kClearedJniWeakGlobal) {
// This is a special case where it's okay to return NULL.
return NULL;
}
break;
}
case kSirtOrInvalid:
default:
// TODO: make stack indirect reference table lookup more efficient
// Check if this is a local reference in the SIRT
if (SirtContains(obj)) {
result = *reinterpret_cast<Object**>(obj); // Read from SIRT
} else if (jni_env_->work_around_app_jni_bugs) {
// Assume an invalid local reference is actually a direct pointer.
result = reinterpret_cast<Object*>(obj);
} else {
result = kInvalidIndirectRefObject;
}
}
if (result == NULL) {
LOG(ERROR) << "JNI ERROR (app bug): use of deleted " << kind << ": " << obj;
JniAbort(NULL);
} else {
if (result != kInvalidIndirectRefObject) {
Heap::VerifyObject(result);
}
}
return result;
}
class CountStackDepthVisitor : public Thread::StackVisitor {
public:
CountStackDepthVisitor() : depth_(0), skip_depth_(0), skipping_(true) {}
virtual void VisitFrame(const Frame& frame, uintptr_t pc) {
// We want to skip frames up to and including the exception's constructor.
// Note we also skip the frame if it doesn't have a method (namely the callee
// save frame)
DCHECK(gThrowable != NULL);
if (skipping_ && frame.HasMethod() && !gThrowable->IsAssignableFrom(frame.GetMethod()->GetDeclaringClass())) {
skipping_ = false;
}
if (!skipping_) {
++depth_;
} else {
++skip_depth_;
}
}
int GetDepth() const {
return depth_;
}
int GetSkipDepth() const {
return skip_depth_;
}
private:
uint32_t depth_;
uint32_t skip_depth_;
bool skipping_;
};
class BuildInternalStackTraceVisitor : public Thread::StackVisitor {
public:
explicit BuildInternalStackTraceVisitor(int depth, int skip_depth, ScopedJniThreadState& ts)
: skip_depth_(skip_depth), count_(0) {
// Allocate method trace with an extra slot that will hold the PC trace
method_trace_ = Runtime::Current()->GetClassLinker()->AllocObjectArray<Object>(depth + 1);
// Register a local reference as IntArray::Alloc may trigger GC
local_ref_ = AddLocalReference<jobject>(ts.Env(), method_trace_);
pc_trace_ = IntArray::Alloc(depth);
#ifdef MOVING_GARBAGE_COLLECTOR
// Re-read after potential GC
method_trace = Decode<ObjectArray<Object>*>(ts.Env(), local_ref_);
#endif
// Save PC trace in last element of method trace, also places it into the
// object graph.
method_trace_->Set(depth, pc_trace_);
}
virtual ~BuildInternalStackTraceVisitor() {}
virtual void VisitFrame(const Frame& frame, uintptr_t pc) {
if (skip_depth_ > 0) {
skip_depth_--;
return;
}
method_trace_->Set(count_, frame.GetMethod());
pc_trace_->Set(count_, pc);
++count_;
}
jobject GetInternalStackTrace() const {
return local_ref_;
}
private:
// How many more frames to skip.
int32_t skip_depth_;
// Current position down stack trace
uint32_t count_;
// Array of return PC values
IntArray* pc_trace_;
// An array of the methods on the stack, the last entry is a reference to the
// PC trace
ObjectArray<Object>* method_trace_;
// Local indirect reference table entry for method trace
jobject local_ref_;
};
void Thread::WalkStack(StackVisitor* visitor) const {
Frame frame = GetTopOfStack();
uintptr_t pc = top_of_managed_stack_pc_;
// TODO: enable this CHECK after native_to_managed_record_ is initialized during startup.
// CHECK(native_to_managed_record_ != NULL);
NativeToManagedRecord* record = native_to_managed_record_;
while (frame.GetSP() != 0) {
for ( ; frame.GetMethod() != 0; frame.Next()) {
DCHECK(frame.GetMethod()->IsWithinCode(pc));
visitor->VisitFrame(frame, pc);
pc = frame.GetReturnPC();
}
if (record == NULL) {
break;
}
// last_tos should return Frame instead of sp?
frame.SetSP(reinterpret_cast<Method**>(record->last_top_of_managed_stack_));
pc = record->last_top_of_managed_stack_pc_;
record = record->link_;
}
}
void Thread::WalkStackUntilUpCall(StackVisitor* visitor, bool include_upcall) const {
Frame frame = GetTopOfStack();
uintptr_t pc = top_of_managed_stack_pc_;
if (frame.GetSP() != 0) {
for ( ; frame.GetMethod() != 0; frame.Next()) {
DCHECK(frame.GetMethod()->IsWithinCode(pc));
visitor->VisitFrame(frame, pc);
pc = frame.GetReturnPC();
}
if (include_upcall) {
visitor->VisitFrame(frame, pc);
}
}
}
jobject Thread::CreateInternalStackTrace(JNIEnv* env) const {
// Compute depth of stack
CountStackDepthVisitor count_visitor;
WalkStack(&count_visitor);
int32_t depth = count_visitor.GetDepth();
int32_t skip_depth = count_visitor.GetSkipDepth();
// Transition into runnable state to work on Object*/Array*
ScopedJniThreadState ts(env);
// Build internal stack trace
BuildInternalStackTraceVisitor build_trace_visitor(depth, skip_depth, ts);
WalkStack(&build_trace_visitor);
return build_trace_visitor.GetInternalStackTrace();
}
jobjectArray Thread::InternalStackTraceToStackTraceElementArray(JNIEnv* env, jobject internal,
jobjectArray output_array, int* stack_depth) {
// Transition into runnable state to work on Object*/Array*
ScopedJniThreadState ts(env);
// Decode the internal stack trace into the depth, method trace and PC trace
ObjectArray<Object>* method_trace =
down_cast<ObjectArray<Object>*>(Decode<Object*>(ts.Env(), internal));
int32_t depth = method_trace->GetLength()-1;
IntArray* pc_trace = down_cast<IntArray*>(method_trace->Get(depth));
ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
jobjectArray result;
ObjectArray<StackTraceElement>* java_traces;
if (output_array != NULL) {
// Reuse the array we were given.
result = output_array;
java_traces = reinterpret_cast<ObjectArray<StackTraceElement>*>(Decode<Array*>(env,
output_array));
// ...adjusting the number of frames we'll write to not exceed the array length.
depth = std::min(depth, java_traces->GetLength());
} else {
// Create java_trace array and place in local reference table
java_traces = class_linker->AllocStackTraceElementArray(depth);
result = AddLocalReference<jobjectArray>(ts.Env(), java_traces);
}
if (stack_depth != NULL) {
*stack_depth = depth;
}
for (int32_t i = 0; i < depth; ++i) {
// Prepare parameters for StackTraceElement(String cls, String method, String file, int line)
Method* method = down_cast<Method*>(method_trace->Get(i));
uint32_t native_pc = pc_trace->Get(i);
Class* klass = method->GetDeclaringClass();
const DexFile& dex_file = class_linker->FindDexFile(klass->GetDexCache());
std::string class_name(PrettyDescriptor(klass->GetDescriptor()));
// Allocate element, potentially triggering GC
StackTraceElement* obj =
StackTraceElement::Alloc(String::AllocFromModifiedUtf8(class_name.c_str()),
method->GetName(),
klass->GetSourceFile(),
dex_file.GetLineNumFromPC(method,
method->ToDexPC(native_pc)));
#ifdef MOVING_GARBAGE_COLLECTOR
// Re-read after potential GC
java_traces = Decode<ObjectArray<Object>*>(ts.Env(), result);
method_trace = down_cast<ObjectArray<Object>*>(Decode<Object*>(ts.Env(), internal));
pc_trace = down_cast<IntArray*>(method_trace->Get(depth));
#endif
java_traces->Set(i, obj);
}
return result;
}
void Thread::ThrowNewExceptionF(const char* exception_class_descriptor, const char* fmt, ...) {
va_list args;
va_start(args, fmt);
ThrowNewExceptionV(exception_class_descriptor, fmt, args);
va_end(args);
}
void Thread::ThrowNewExceptionV(const char* exception_class_descriptor, const char* fmt, va_list ap) {
std::string msg;
StringAppendV(&msg, fmt, ap);
ThrowNewException(exception_class_descriptor, msg.c_str());
}
void Thread::ThrowNewException(const char* exception_class_descriptor, const char* msg) {
// Convert "Ljava/lang/Exception;" into JNI-style "java/lang/Exception".
CHECK_EQ('L', exception_class_descriptor[0]);
std::string descriptor(exception_class_descriptor + 1);
CHECK_EQ(';', descriptor[descriptor.length() - 1]);
descriptor.erase(descriptor.length() - 1);
JNIEnv* env = GetJniEnv();
jclass exception_class = env->FindClass(descriptor.c_str());
CHECK(exception_class != NULL) << "descriptor=\"" << descriptor << "\"";
int rc = env->ThrowNew(exception_class, msg);
CHECK_EQ(rc, JNI_OK);
env->DeleteLocalRef(exception_class);
}
void Thread::ThrowOutOfMemoryError() {
UNIMPLEMENTED(FATAL);
}
class CatchBlockStackVisitor : public Thread::StackVisitor {
public:
CatchBlockStackVisitor(Class* to_find, Context* ljc)
: found_(false), to_find_(to_find), long_jump_context_(ljc), native_method_count_(0) {
#ifndef NDEBUG
handler_pc_ = 0xEBADC0DE;
handler_frame_.SetSP(reinterpret_cast<Method**>(0xEBADF00D));
#endif
}
virtual void VisitFrame(const Frame& fr, uintptr_t pc) {
if (!found_) {
Method* method = fr.GetMethod();
if (method == NULL) {
// This is the upcall, we remember the frame and last_pc so that we may
// long jump to them
handler_pc_ = pc;
handler_frame_ = fr;
return;
}
uint32_t dex_pc = DexFile::kDexNoIndex;
if (method->IsPhony()) {
// ignore callee save method
} else if (method->IsNative()) {
native_method_count_++;
} else {
// Move the PC back 2 bytes as a call will frequently terminate the
// decoding of a particular instruction and we want to make sure we
// get the Dex PC of the instruction with the call and not the
// instruction following.
pc -= 2;
dex_pc = method->ToDexPC(pc);
}
if (dex_pc != DexFile::kDexNoIndex) {
uint32_t found_dex_pc = method->FindCatchBlock(to_find_, dex_pc);
if (found_dex_pc != DexFile::kDexNoIndex) {
found_ = true;
handler_pc_ = method->ToNativePC(found_dex_pc);
handler_frame_ = fr;
}
}
if (!found_) {
// Caller may be handler, fill in callee saves in context
long_jump_context_->FillCalleeSaves(fr);
}
}
}
// Did we find a catch block yet?
bool found_;
// The type of the exception catch block to find
Class* to_find_;
// Frame with found handler or last frame if no handler found
Frame handler_frame_;
// PC to branch to for the handler
uintptr_t handler_pc_;
// Context that will be the target of the long jump
Context* long_jump_context_;
// Number of native methods passed in crawl (equates to number of SIRTs to pop)
uint32_t native_method_count_;
};
void Thread::DeliverException() {
Throwable *exception = GetException(); // Set exception on thread
CHECK(exception != NULL);
Context* long_jump_context = GetLongJumpContext();
CatchBlockStackVisitor catch_finder(exception->GetClass(), long_jump_context);
WalkStackUntilUpCall(&catch_finder, true);
// Pop any SIRT
if (catch_finder.native_method_count_ == 1) {
PopSirt();
} else {
// We only expect the stack crawl to have passed 1 native method as it's terminated
// by an up call
DCHECK_EQ(catch_finder.native_method_count_, 0u);
}
long_jump_context->SetSP(reinterpret_cast<intptr_t>(catch_finder.handler_frame_.GetSP()));
long_jump_context->SetPC(catch_finder.handler_pc_);
long_jump_context->DoLongJump();
}
Context* Thread::GetLongJumpContext() {
Context* result = long_jump_context_;
if (result == NULL) {
result = Context::Create();
long_jump_context_ = result;
}
return result;
}
bool Thread::HoldsLock(Object* object) {
if (object == NULL) {
return false;
}
return object->GetLockOwner() == thin_lock_id_;
}
bool Thread::IsDaemon() {
return gThread_daemon->GetBoolean(peer_);
}
// blx is 2-byte in Thumb2. Need to offset PC back to a call site.
static const int kThumb2InstSize = 2;
class ReferenceMapVisitor : public Thread::StackVisitor {
public:
ReferenceMapVisitor(Context* context, Heap::RootVisitor* root_visitor, void* arg) :
context_(context), root_visitor_(root_visitor), arg_(arg) {
}
void VisitFrame(const Frame& frame, uintptr_t pc) {
Method* m = frame.GetMethod();
// Process register map (which native and callee save methods don't have)
if (!m->IsNative() && !m->IsPhony()) {
UniquePtr<art::DexVerifier::RegisterMap> map(art::DexVerifier::GetExpandedRegisterMap(m));
const uint8_t* reg_bitmap = art::DexVerifier::RegisterMapGetLine(
map.get(),
m->ToDexPC(pc -kThumb2InstSize));
LOG(INFO) << "Visiting stack roots in " << PrettyMethod(m, false)
<< "@ PC: " << m->ToDexPC(pc - kThumb2InstSize);
CHECK(reg_bitmap != NULL);
ShortArray* vmap = m->GetVMapTable();
// For all dex registers
for (int reg = 0; reg < m->NumRegisters(); ++reg) {
// Does this register hold a reference?
if (TestBitmap(reg, reg_bitmap)) {
// Is the reference in the context or on the stack?
bool in_context = false;
int vmap_offset = -1;
// TODO: take advantage of the registers being ordered
for (int i = 0; i < vmap->GetLength(); i++) {
if (vmap->Get(i) == reg) {
in_context = true;
vmap_offset = i;
break;
}
}
Object* ref;
if (in_context) {
// Compute the register we need to load from the context
uint32_t spill_mask = m->GetCoreSpillMask();
uint32_t reg = 0;
for (int i = 0; i < vmap_offset; i++) {
while ((spill_mask & 1) == 0) {
CHECK_NE(spill_mask, 0u);
spill_mask >>= 1;
reg++;
}
}
ref = reinterpret_cast<Object*>(context_->GetGPR(reg));
} else {
ref = reinterpret_cast<Object*>(frame.GetVReg(m ,reg));
}
if (ref != NULL) {
root_visitor_(ref, arg_);
}
}
}
}
context_->FillCalleeSaves(frame);
}
private:
bool TestBitmap(int reg, const uint8_t* reg_vector) {
return ((reg_vector[reg / 8] >> (reg % 8)) & 0x01) != 0;
}
// Context used to build up picture of callee saves
Context* context_;
// Call-back when we visit a root
Heap::RootVisitor* root_visitor_;
// Argument to call-back
void* arg_;
};
void Thread::VisitRoots(Heap::RootVisitor* visitor, void* arg) {
if (exception_ != NULL) {
visitor(exception_, arg);
}
if (peer_ != NULL) {
visitor(peer_, arg);
}
jni_env_->locals.VisitRoots(visitor, arg);
jni_env_->monitors.VisitRoots(visitor, arg);
SirtVisitRoots(visitor, arg);
// Cheat and steal the long jump context. Assume that we are not doing a GC during exception
// delivery.
Context* context = GetLongJumpContext();
// Visit roots on this thread's stack
ReferenceMapVisitor mapper(context, visitor, arg);
WalkStack(&mapper);
}
static const char* kStateNames[] = {
"Terminated",
"Runnable",
"TimedWaiting",
"Blocked",
"Waiting",
"Initializing",
"Starting",
"Native",
"VmWait",
"Suspended",
};
std::ostream& operator<<(std::ostream& os, const Thread::State& state) {
int32_t int_state = static_cast<int32_t>(state);
if (state >= Thread::kTerminated && state <= Thread::kSuspended) {
os << kStateNames[int_state];
} else {
os << "State[" << int_state << "]";
}
return os;
}
std::ostream& operator<<(std::ostream& os, const Thread& thread) {
os << "Thread[" << &thread
<< ",pthread_t=" << thread.GetImpl()
<< ",tid=" << thread.GetTid()
<< ",id=" << thread.GetThinLockId()
<< ",state=" << thread.GetState()
<< ",peer=" << thread.GetPeer()
<< "]";
return os;
}
} // namespace art