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diff --git a/Source/JavaScriptCore/interpreter/CLoopStack.cpp b/Source/JavaScriptCore/interpreter/CLoopStack.cpp
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+++ b/Source/JavaScriptCore/interpreter/CLoopStack.cpp
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+/*
+ * Copyright (C) 2008, 2013-2016 Apple 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:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "CLoopStack.h"
+
+#if !ENABLE(JIT)
+
+#include "CLoopStackInlines.h"
+#include "ConservativeRoots.h"
+#include "Interpreter.h"
+#include "JSCInlines.h"
+#include "Options.h"
+#include <wtf/Lock.h>
+
+namespace JSC {
+
+static size_t committedBytesCount = 0;
+
+static size_t commitSize()
+{
+    static size_t size = std::max<size_t>(16 * 1024, pageSize());
+    return size;
+}
+
+static StaticLock stackStatisticsMutex;
+
+CLoopStack::CLoopStack(VM& vm)
+    : m_vm(vm)
+    , m_topCallFrame(vm.topCallFrame)
+    , m_end(0)
+    , m_softReservedZoneSizeInRegisters(0)
+{
+    size_t capacity = Options::maxPerThreadStackUsage();
+    ASSERT(capacity && isPageAligned(capacity));
+
+    m_reservation = PageReservation::reserve(WTF::roundUpToMultipleOf(commitSize(), capacity), OSAllocator::JSVMStackPages);
+    setCLoopStackLimit(highAddress());
+    m_commitTop = highAddress();
+    
+    m_lastStackTop = baseOfStack();
+
+    m_topCallFrame = 0;
+}
+
+CLoopStack::~CLoopStack()
+{
+    ptrdiff_t sizeToDecommit = reinterpret_cast<char*>(highAddress()) - reinterpret_cast<char*>(m_commitTop);
+    m_reservation.decommit(reinterpret_cast<void*>(m_commitTop), sizeToDecommit);
+    addToCommittedByteCount(-sizeToDecommit);
+    m_reservation.deallocate();
+}
+
+bool CLoopStack::grow(Register* newTopOfStack)
+{
+    Register* newTopOfStackWithReservedZone = newTopOfStack - m_softReservedZoneSizeInRegisters;
+
+    // If we have already committed enough memory to satisfy this request,
+    // just update the end pointer and return.
+    if (newTopOfStackWithReservedZone >= m_commitTop) {
+        setCLoopStackLimit(newTopOfStack);
+        return true;
+    }
+
+    // Compute the chunk size of additional memory to commit, and see if we
+    // have it still within our budget. If not, we'll fail to grow and
+    // return false.
+    ptrdiff_t delta = reinterpret_cast<char*>(m_commitTop) - reinterpret_cast<char*>(newTopOfStackWithReservedZone);
+    delta = WTF::roundUpToMultipleOf(commitSize(), delta);
+    Register* newCommitTop = m_commitTop - (delta / sizeof(Register));
+    if (newCommitTop < reservationTop())
+        return false;
+
+    // Otherwise, the growth is still within our budget. Commit it and return true.
+    m_reservation.commit(newCommitTop, delta);
+    addToCommittedByteCount(delta);
+    m_commitTop = newCommitTop;
+    setCLoopStackLimit(newTopOfStack);
+    return true;
+}
+
+void CLoopStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots, JITStubRoutineSet& jitStubRoutines, CodeBlockSet& codeBlocks)
+{
+    conservativeRoots.add(topOfStack() + 1, highAddress(), jitStubRoutines, codeBlocks);
+}
+
+void CLoopStack::sanitizeStack()
+{
+#if !ASAN_ENABLED
+    ASSERT(topOfStack() <= baseOfStack());
+    
+    if (m_lastStackTop < topOfStack()) {
+        char* begin = reinterpret_cast<char*>(m_lastStackTop + 1);
+        char* end = reinterpret_cast<char*>(topOfStack() + 1);
+        memset(begin, 0, end - begin);
+    }
+    
+    m_lastStackTop = topOfStack();
+#endif
+}
+
+void CLoopStack::releaseExcessCapacity()
+{
+    Register* highAddressWithReservedZone = highAddress() - m_softReservedZoneSizeInRegisters;
+    ptrdiff_t delta = reinterpret_cast<char*>(highAddressWithReservedZone) - reinterpret_cast<char*>(m_commitTop);
+    m_reservation.decommit(m_commitTop, delta);
+    addToCommittedByteCount(-delta);
+    m_commitTop = highAddressWithReservedZone;
+}
+
+void CLoopStack::addToCommittedByteCount(long byteCount)
+{
+    LockHolder locker(stackStatisticsMutex);
+    ASSERT(static_cast<long>(committedBytesCount) + byteCount > -1);
+    committedBytesCount += byteCount;
+}
+
+void CLoopStack::setSoftReservedZoneSize(size_t reservedZoneSize)
+{
+    m_softReservedZoneSizeInRegisters = reservedZoneSize / sizeof(Register);
+    if (m_commitTop >= (m_end + 1) - m_softReservedZoneSizeInRegisters)
+        grow(m_end + 1);
+}
+
+bool CLoopStack::isSafeToRecurse() const
+{
+    void* reservationLimit = reinterpret_cast<int8_t*>(reservationTop() + m_softReservedZoneSizeInRegisters);
+    return !m_topCallFrame || (m_topCallFrame->topOfFrame() > reservationLimit);
+}
+
+size_t CLoopStack::committedByteCount()
+{
+    LockHolder locker(stackStatisticsMutex);
+    return committedBytesCount;
+}
+
+} // namespace JSC
+
+#endif // !ENABLE(JIT)