Refactor the Heap into ThreadHeap to prepare for per thread heaps

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

Index: third_party/WebKit/Source/platform/heap/SafePoint.cpp
diff --git a/third_party/WebKit/Source/platform/heap/SafePoint.cpp b/third_party/WebKit/Source/platform/heap/SafePoint.cpp
index a75bb509ce63d75ef0b89f2f48e8b1b2d88074a8..470cb11266cae0ac0a498d8dcf4d9828d4af3b44 100644
--- a/third_party/WebKit/Source/platform/heap/SafePoint.cpp
+++ b/third_party/WebKit/Source/platform/heap/SafePoint.cpp
@@ -17,9 +17,10 @@ static double lockingTimeout()
     return 0.100;
 }
 
-SafePointBarrier::SafePointBarrier()
+SafePointBarrier::SafePointBarrier(MultiThreadGCGroup* gcGroup)
     : m_canResume(1)
     , m_unparkedThreadCount(0)
+    , m_gcGroup(gcGroup)
 {
 }
 
@@ -31,17 +32,16 @@ bool SafePointBarrier::parkOthers()
 {
     ASSERT(ThreadState::current()->isAtSafePoint());
 
-    ThreadState* current = ThreadState::current();
     // Lock threadAttachMutex() to prevent threads from attaching.
-    ThreadState::lockThreadAttachMutex();
-    ThreadState::AttachedThreadStateSet& threads = ThreadState::attachedThreads();
+    m_gcGroup->lockThreadAttachMutex();
+    const HashSet<ThreadState*>& threads = m_gcGroup->threads();
 
     MutexLocker locker(m_mutex);
     atomicAdd(&m_unparkedThreadCount, threads.size());
     releaseStore(&m_canResume, 0);
 
     for (ThreadState* state : threads) {
-        if (state == current)
+        if (state->isAtSafePoint()) // MEMO: original code: if (state == current)

[haraken, 2016/01/28 15:52:50]

Why do you need to make this change?

This change may be correct but I don't want to touch the SafePoint's algorithm
as much as possible.

[keishi, 2016/02/29 06:02:33]

Done. Just thought it made more sense.

             continue;
 
         for (auto& interruptor : state->interruptors())
@@ -63,7 +63,7 @@ bool SafePointBarrier::parkOthers()
 
 void SafePointBarrier::resumeOthers(bool barrierLocked)
 {
-    ThreadState::AttachedThreadStateSet& threads = ThreadState::attachedThreads();
+    const HashSet<ThreadState*>& threads = m_gcGroup->threads();
     atomicSubtract(&m_unparkedThreadCount, threads.size());
     releaseStore(&m_canResume, 1);
 
@@ -76,7 +76,7 @@ void SafePointBarrier::resumeOthers(bool barrierLocked)
         m_resume.broadcast();
     }
 
-    ThreadState::unlockThreadAttachMutex();
+    m_gcGroup->unlockThreadAttachMutex();
     ASSERT(ThreadState::current()->isAtSafePoint());
 }