Use enum for per thread heap enabled flag

third_party/WebKit/Source/platform/heap/ThreadState.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 127 matching lines @@
         // and we need to resume the other threads.
         if (m_shouldResumeThreads)
             m_state->heap().resume();
     }
 
 private:
     ThreadState* m_state;
     bool m_shouldResumeThreads;
 };
 
-ThreadState::ThreadState(bool perThreadHeapEnabled)
+ThreadState::ThreadState(ThreadHeapMode threadHeapMode)
     : m_thread(currentThread())
     , m_persistentRegion(wrapUnique(new PersistentRegion()))
 #if OS(WIN) && COMPILER(MSVC)
     , m_threadStackSize(0)
 #endif
     , m_startOfStack(reinterpret_cast<intptr_t*>(StackFrameDepth::getStackStart()))
     , m_endOfStack(reinterpret_cast<intptr_t*>(StackFrameDepth::getStackStart()))
     , m_safePointScopeMarker(nullptr)
     , m_atSafePoint(false)
     , m_interruptors()
     , m_sweepForbidden(false)
     , m_noAllocationCount(0)
     , m_gcForbiddenCount(0)
     , m_accumulatedSweepingTime(0)
     , m_vectorBackingArenaIndex(BlinkGC::Vector1ArenaIndex)
     , m_currentArenaAges(0)
-    , m_perThreadHeapEnabled(perThreadHeapEnabled)
+    , m_threadHeapMode(threadHeapMode)
     , m_isTerminating(false)
     , m_gcMixinMarker(nullptr)
     , m_shouldFlushHeapDoesNotContainCache(false)
     , m_gcState(NoGCScheduled)
     , m_threadLocalWeakCallbackStack(CallbackStack::create())
     , m_isolate(nullptr)
     , m_traceDOMWrappers(nullptr)
     , m_invalidateDeadObjectsInWrappersMarkingDeque(nullptr)
 #if defined(ADDRESS_SANITIZER)
     , m_asanFakeStack(__asan_get_current_fake_stack())
 #endif
 #if defined(LEAK_SANITIZER)
     , m_disabledStaticPersistentsRegistration(0)
 #endif
     , m_allocatedObjectSize(0)
     , m_markedObjectSize(0)
     , m_reportedMemoryToV8(0)
 {
     ASSERT(checkThread());
     ASSERT(!**s_threadSpecific);
     **s_threadSpecific = this;
 
-    if (m_perThreadHeapEnabled) {
+    switch (m_threadHeapMode) {
+    case MainThreadHeapMode:
+        if (isMainThread()) {
+            s_mainThreadStackStart = reinterpret_cast<uintptr_t>(m_startOfStack) - sizeof(void*);
+            size_t underestimatedStackSize = StackFrameDepth::getUnderestimatedStackSize();
+            if (underestimatedStackSize > sizeof(void*))
+                s_mainThreadUnderestimatedStackSize = underestimatedStackSize - sizeof(void*);
+            m_heap = new ThreadHeap();
+        } else {
+            m_heap = &ThreadState::mainThreadState()->heap();
+        }
+        break;
+    case PerThreadHeapMode:
         m_heap = new ThreadHeap();
-    } else if (isMainThread()) {
-        s_mainThreadStackStart = reinterpret_cast<uintptr_t>(m_startOfStack) - sizeof(void*);
-        size_t underestimatedStackSize = StackFrameDepth::getUnderestimatedStackSize();
-        if (underestimatedStackSize > sizeof(void*))
-            s_mainThreadUnderestimatedStackSize = underestimatedStackSize - sizeof(void*);
-        m_heap = new ThreadHeap();
-    } else {
-        m_heap = &ThreadState::mainThreadState()->heap();
+        break;
+    default:
+        NOTREACHED();

[nhiroki, 2016/09/21 05:15:26]

Is "default" case necessary?

[keishi, 2016/09/21 07:06:37]

Removed.

     }
     ASSERT(m_heap);
     m_heap->attach(this);
 
     for (int arenaIndex = 0; arenaIndex < BlinkGC::LargeObjectArenaIndex; arenaIndex++)
         m_arenas[arenaIndex] = new NormalPageArena(this, arenaIndex);
     m_arenas[BlinkGC::LargeObjectArenaIndex] = new LargeObjectArena(this, BlinkGC::LargeObjectArenaIndex);
 
     m_likelyToBePromptlyFreed = wrapArrayUnique(new int[likelyToBePromptlyFreedArraySize]);
     clearArenaAges();
@@ skipping 44 matching lines @@
     RELEASE_ASSERT(m_threadStackSize > 4 * 0x1000);
     m_threadStackSize -= 4 * 0x1000;
     return m_threadStackSize;
 }
 #endif
 
 void ThreadState::attachMainThread()
 {
     RELEASE_ASSERT(!ProcessHeap::s_shutdownComplete);
     s_threadSpecific = new WTF::ThreadSpecific<ThreadState*>();
-    new (s_mainThreadStateStorage) ThreadState(false);
+    new (s_mainThreadStateStorage) ThreadState(MainThreadHeapMode);
 }
 
-void ThreadState::attachCurrentThread(bool perThreadHeapEnabled)
+void ThreadState::attachCurrentThread(ThreadHeapMode threadHeapMode)
 {
     RELEASE_ASSERT(!ProcessHeap::s_shutdownComplete);
-    new ThreadState(perThreadHeapEnabled);
+    new ThreadState(threadHeapMode);
 }
 
 void ThreadState::cleanupPages()
 {
     ASSERT(checkThread());
     for (int i = 0; i < BlinkGC::NumberOfArenas; ++i)
         m_arenas[i]->cleanupPages();
 }
 
 void ThreadState::runTerminationGC()
@@ skipping 1468 matching lines @@
     for (int i = 0; i < 5; ++i) {
         collectGarbage(BlinkGC::NoHeapPointersOnStack, BlinkGC::GCWithSweep, BlinkGC::ForcedGC);
         size_t liveObjects = heap().heapStats().markedObjectSize();
         if (liveObjects == previousLiveObjects)
             break;
         previousLiveObjects = liveObjects;
     }
 }
 
 } // namespace blink