关于Signal Catcher线程中对线程的理解

Thread* Thread::Attach(const char* thread_name, bool as_daemon, jobject thread_group,bool create_peer) {
    Runtime* runtime = Runtime::Current();
    ......
    Thread* self;
    {
        MutexLock mu(nullptr, *Locks::runtime_shutdown_lock_);
        if (runtime->IsShuttingDownLocked()) {
        ......
        } else {
                Runtime::Current()->StartThreadBirth();
                self = new Thread(as_daemon); //新建一个Thread对象
                bool init_success = self->Init(runtime->GetThreadList(), runtime->GetJavaVM()); //调用init函数
                Runtime::Current()->EndThreadBirth();
                if (!init_success) {
                    delete self;
                    return nullptr;
                }
         }
      }
    ......
    self->InitStringEntryPoints();  
    CHECK_NE(self->GetState(), kRunnable);
    self->SetState(kNative);
    ......
    return self;
}

inline ThreadState Thread::SetState(ThreadState new_state) {
  // Cannot use this code to change into Runnable as changing to Runnable should fail if
  // old_state_and_flags.suspend_request is true.
  DCHECK_NE(new_state, kRunnable);
  if (kIsDebugBuild && this != Thread::Current()) {
    std::string name;
    GetThreadName(name);
    LOG(FATAL) << "Thread \"" << name << "\"(" << this << " != Thread::Current()="
               << Thread::Current() << ") changing state to " << new_state;
  }
  union StateAndFlags old_state_and_flags;
  old_state_and_flags.as_int = tls32_.state_and_flags.as_int;
  tls32_.state_and_flags.as_struct.state = new_state;
  return static_cast<ThreadState>(old_state_and_flags.as_struct.state);
}

enum ThreadState {
  //                                   Thread.State   JDWP state
  kTerminated = 66,                 // TERMINATED     TS_ZOMBIE    Thread.run has returned, but Thread* still around
  kRunnable,                        // RUNNABLE       TS_RUNNING   runnable
  kTimedWaiting,                    // TIMED_WAITING  TS_WAIT      in Object.wait() with a timeout
  kSleeping,                        // TIMED_WAITING  TS_SLEEPING  in Thread.sleep()
  kBlocked,                         // BLOCKED        TS_MONITOR   blocked on a monitor
  kWaiting,                         // WAITING        TS_WAIT      in Object.wait()
  kWaitingForGcToComplete,          // WAITING        TS_WAIT      blocked waiting for GC
  kWaitingForCheckPointsToRun,      // WAITING        TS_WAIT      GC waiting for checkpoints to run
  kWaitingPerformingGc,             // WAITING        TS_WAIT      performing GC
  kWaitingForDebuggerSend,          // WAITING        TS_WAIT      blocked waiting for events to be sent
  kWaitingForDebuggerToAttach,      // WAITING        TS_WAIT      blocked waiting for debugger to attach
  kWaitingInMainDebuggerLoop,       // WAITING        TS_WAIT      blocking/reading/processing debugger events
  kWaitingForDebuggerSuspension,    // WAITING        TS_WAIT      waiting for debugger suspend all
  kWaitingForJniOnLoad,             // WAITING        TS_WAIT      waiting for execution of dlopen and JNI on load code
  kWaitingForSignalCatcherOutput,   // WAITING        TS_WAIT      waiting for signal catcher IO to complete
  kWaitingInMainSignalCatcherLoop,  // WAITING        TS_WAIT      blocking/reading/processing signals
  kWaitingForDeoptimization,        // WAITING        TS_WAIT      waiting for deoptimization suspend all
  kWaitingForMethodTracingStart,    // WAITING        TS_WAIT      waiting for method tracing to start
  kWaitingForVisitObjects,          // WAITING        TS_WAIT      waiting for visiting objects
  kWaitingForGetObjectsAllocated,   // WAITING        TS_WAIT      waiting for getting the number of allocated objects
  kStarting,                        // NEW            TS_WAIT      native thread started, not yet ready to run managed code
  kNative,                          // RUNNABLE       TS_RUNNING   running in a JNI native method
  kSuspended,                       // RUNNABLE       TS_RUNNING   suspended by GC or debugger
};