Bug 1477512: Part 5 - Rearrange the fields of nsThread for better pac…

…king. r=erahm

This takes 16 bytes off of the allocated size of each instance.

MozReview-Commit-ID: AhfN6MWvVL1

--HG--
extra : rebase_source : badc6ab690f2c4e0184ac0b51b29f81fb11279c6
extra : absorb_source : 0f685515a6946c89e9467c8b1e8548c989b1907b
extra : histedit_source : 7bfb5db39b23c1d262819c22a6e5fcd884c52504

xpcom/threads/nsThread.cpp

@@ -650,18 +650,18 @@ nsThread::nsThread(NotNull<SynchronizedEventQueue*> aQueue,
                    uint32_t aStackSize)
   : mEvents(aQueue.get())
   , mEventTarget(new ThreadEventTarget(mEvents.get(), aMainThread == MAIN_THREAD))
+  , mShutdownContext(nullptr)
   , mScriptObserver(nullptr)
-  , mPriority(PRIORITY_NORMAL)
   , mThread(nullptr)
-  , mNestedEventLoopDepth(0)
   , mStackSize(aStackSize)
-  , mShutdownContext(nullptr)
+  , mNestedEventLoopDepth(0)
+  , mCurrentEventLoopDepth(-1)
   , mShutdownRequired(false)
-  , mIsMainThread(aMainThread)
+  , mPriority(PRIORITY_NORMAL)
+  , mIsMainThread(uint8_t(aMainThread))
   , mCanInvokeJS(false)
   , mCurrentEvent(nullptr)
   , mCurrentEventStart(TimeStamp::Now())
-  , mCurrentEventLoopDepth(-1)
   , mCurrentPerformanceCounter(nullptr)
 {
 }
@@ -1093,7 +1093,7 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult)
   bool reallyWait = aMayWait && (mNestedEventLoopDepth > 0 || !ShuttingDown());
 
   Maybe<Scheduler::EventLoopActivation> activation;
-  if (mIsMainThread == MAIN_THREAD) {
+  if (IsMainThread()) {
     DoMainThreadSpecificProcessing(reallyWait);
     activation.emplace();
   }
@@ -1138,7 +1138,7 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult)
     if (event) {
       LOG(("THRD(%p) running [%p]\n", this, event.get()));
 
-      if (MAIN_THREAD == mIsMainThread) {
+      if (IsMainThread()) {
         BackgroundHangMonitor().NotifyActivity();
       }
 
@@ -1158,12 +1158,12 @@ nsThread::ProcessNextEvent(bool aMayWait, bool* aResult)
       Array<char, kRunnableNameBufSize> restoreRunnableName;
       restoreRunnableName[0] = '\0';
       auto clear = MakeScopeExit([&] {
-        if (MAIN_THREAD == mIsMainThread) {
+        if (IsMainThread()) {
           MOZ_ASSERT(NS_IsMainThread());
           sMainThreadRunnableName = restoreRunnableName;
         }
       });
-      if (MAIN_THREAD == mIsMainThread) {
+      if (IsMainThread()) {
         nsAutoCString name;
         GetLabeledRunnableName(event, name, priority);
 
@@ -1361,7 +1361,7 @@ nsThread::SetScriptObserver(mozilla::CycleCollectedJSContext* aScriptObserver)
 void
 nsThread::DoMainThreadSpecificProcessing(bool aReallyWait)
 {
-  MOZ_ASSERT(mIsMainThread == MAIN_THREAD);
+  MOZ_ASSERT(IsMainThread());
 
   ipc::CancelCPOWs();
 

xpcom/threads/nsThread.h

@@ -176,31 +176,41 @@ class nsThread
   RefPtr<mozilla::SynchronizedEventQueue> mEvents;
   RefPtr<mozilla::ThreadEventTarget> mEventTarget;
 
+  // The shutdown contexts for any other threads we've asked to shut down.
+  nsTArray<nsAutoPtr<struct nsThreadShutdownContext>> mRequestedShutdownContexts;
+  // The shutdown context for ourselves.
+  struct nsThreadShutdownContext* mShutdownContext;
+
   mozilla::CycleCollectedJSContext* mScriptObserver;
 
-  int32_t   mPriority;
-  uint32_t  mThreadId;
   PRThread* mThread;
-  uint32_t  mNestedEventLoopDepth;
-  uint32_t  mStackSize;
   void*     mStackBase = nullptr;
+  uint32_t  mStackSize;
+  uint32_t  mThreadId;
 
-  // The shutdown context for ourselves.
-  struct nsThreadShutdownContext* mShutdownContext;
-  // The shutdown contexts for any other threads we've asked to shut down.
-  nsTArray<nsAutoPtr<struct nsThreadShutdownContext>> mRequestedShutdownContexts;
+  uint32_t  mNestedEventLoopDepth;
+  uint32_t  mCurrentEventLoopDepth;
 
   mozilla::Atomic<bool> mShutdownRequired;
-  MainThreadFlag mIsMainThread;
+
+  int8_t   mPriority;
+
+  uint8_t  mIsMainThread;
+
+  bool IsMainThread() const
+  {
+    return MainThreadFlag(mIsMainThread) == MAIN_THREAD;
+  }
 
   // Set to true if this thread creates a JSRuntime.
   bool mCanInvokeJS;
 
-  mozilla::TimeStamp mNextIdleDeadline;
   // Used to track which event is being executed by ProcessNextEvent
   nsCOMPtr<nsIRunnable> mCurrentEvent;
+
   mozilla::TimeStamp mCurrentEventStart;
-  uint32_t mCurrentEventLoopDepth;
+  mozilla::TimeStamp mNextIdleDeadline;
+
   RefPtr<mozilla::PerformanceCounter> mCurrentPerformanceCounter;
 };