JavaScriptCore-1218.tar.gz

[apple/javascriptcore.git] / interpreter / JSStack.cpp

diff --git a/interpreter/JSStack.cpp b/interpreter/JSStack.cpp
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+++ b/interpreter/JSStack.cpp
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+/*
+ * Copyright (C) 2008 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 Computer, 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 "JSStack.h"
+#include "JSStackInlines.h"
+
+#include "ConservativeRoots.h"
+#include "Interpreter.h"
+
+namespace JSC {
+
+static size_t committedBytesCount = 0;
+
+static Mutex& stackStatisticsMutex()
+{
+    DEFINE_STATIC_LOCAL(Mutex, staticMutex, ());
+    return staticMutex;
+}    
+
+JSStack::JSStack(VM& vm, size_t capacity)
+    : m_end(0)
+    , m_topCallFrame(vm.topCallFrame)
+{
+    ASSERT(capacity && isPageAligned(capacity));
+
+    m_reservation = PageReservation::reserve(roundUpAllocationSize(capacity * sizeof(Register), commitSize), OSAllocator::JSVMStackPages);
+    m_end = static_cast<Register*>(m_reservation.base());
+    m_commitEnd = static_cast<Register*>(m_reservation.base());
+
+    disableErrorStackReserve();
+
+    m_topCallFrame = 0;
+}
+
+JSStack::~JSStack()
+{
+    void* base = m_reservation.base();
+    m_reservation.decommit(base, reinterpret_cast<intptr_t>(m_commitEnd) - reinterpret_cast<intptr_t>(base));
+    addToCommittedByteCount(-(reinterpret_cast<intptr_t>(m_commitEnd) - reinterpret_cast<intptr_t>(base)));
+    m_reservation.deallocate();
+}
+
+bool JSStack::growSlowCase(Register* newEnd)
+{
+    // If we have already committed enough memory to satisfy this request,
+    // just update the end pointer and return.
+    if (newEnd <= m_commitEnd) {
+        m_end = newEnd;
+        return true;
+    }
+
+    // Compute the chunk size of additional memory to commit, and see if we
+    // have it is still within our budget. If not, we'll fail to grow and
+    // return false.
+    long delta = roundUpAllocationSize(reinterpret_cast<char*>(newEnd) - reinterpret_cast<char*>(m_commitEnd), commitSize);
+    if (reinterpret_cast<char*>(m_commitEnd) + delta > reinterpret_cast<char*>(m_useableEnd))
+        return false;
+
+    // Otherwise, the growth is still within our budget. Go ahead and commit
+    // it and return true.
+    m_reservation.commit(m_commitEnd, delta);
+    addToCommittedByteCount(delta);
+    m_commitEnd = reinterpret_cast_ptr<Register*>(reinterpret_cast<char*>(m_commitEnd) + delta);
+    m_end = newEnd;
+    return true;
+}
+
+void JSStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots)
+{
+    conservativeRoots.add(begin(), getTopOfStack());
+}
+
+void JSStack::gatherConservativeRoots(ConservativeRoots& conservativeRoots, JITStubRoutineSet& jitStubRoutines, DFGCodeBlocks& dfgCodeBlocks)
+{
+    conservativeRoots.add(begin(), getTopOfStack(), jitStubRoutines, dfgCodeBlocks);
+}
+
+void JSStack::releaseExcessCapacity()
+{
+    ptrdiff_t delta = reinterpret_cast<uintptr_t>(m_commitEnd) - reinterpret_cast<uintptr_t>(m_reservation.base());
+    m_reservation.decommit(m_reservation.base(), delta);
+    addToCommittedByteCount(-delta);
+    m_commitEnd = static_cast<Register*>(m_reservation.base());
+}
+
+void JSStack::initializeThreading()
+{
+    stackStatisticsMutex();
+}
+
+size_t JSStack::committedByteCount()
+{
+    MutexLocker locker(stackStatisticsMutex());
+    return committedBytesCount;
+}
+
+void JSStack::addToCommittedByteCount(long byteCount)
+{
+    MutexLocker locker(stackStatisticsMutex());
+    ASSERT(static_cast<long>(committedBytesCount) + byteCount > -1);
+    committedBytesCount += byteCount;
+}
+
+void JSStack::enableErrorStackReserve()
+{
+    m_useableEnd = reservationEnd();
+}
+
+void JSStack::disableErrorStackReserve()
+{
+    char* useableEnd = reinterpret_cast<char*>(reservationEnd()) - commitSize;
+    m_useableEnd = reinterpret_cast_ptr<Register*>(useableEnd);
+
+    // By the time we get here, we are guaranteed to be destructing the last
+    // Interpreter::ErrorHandlingMode that enabled this reserve in the first
+    // place. That means the stack space beyond m_useableEnd before we
+    // enabled the reserve was not previously in use. Hence, it is safe to
+    // shrink back to that m_useableEnd.
+    if (m_end > m_useableEnd) {
+        ASSERT(m_topCallFrame->frameExtent() <= m_useableEnd);
+        shrink(m_useableEnd);
+    }
+}
+
+} // namespace JSC