1 files changed, 122 insertions, 0 deletions
diff --git a/Source/JavaScriptCore/heap/ConservativeRoots.cpp b/Source/JavaScriptCore/heap/ConservativeRoots.cpp
new file mode 100644
index 000000000..05c668c35
--- /dev/null
+++ b/Source/JavaScriptCore/heap/ConservativeRoots.cpp
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2011 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 "ConservativeRoots.h"
+
+#include "CodeBlock.h"
+#include "DFGCodeBlocks.h"
+#include "JSCell.h"
+#include "JSObject.h"
+#include "Structure.h"
+
+namespace JSC {
+
+inline bool isPointerAligned(void* p)
+{
+    return !((intptr_t)(p) & (sizeof(char*) - 1));
+}
+
+ConservativeRoots::ConservativeRoots(const MarkedBlockSet* blocks)
+    : m_roots(m_inlineRoots)
+    , m_size(0)
+    , m_capacity(inlineCapacity)
+    , m_blocks(blocks)
+{
+}
+
+ConservativeRoots::~ConservativeRoots()
+{
+    if (m_roots != m_inlineRoots)
+        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
+}
+
+void ConservativeRoots::grow()
+{
+    size_t newCapacity = m_capacity == inlineCapacity ? nonInlineCapacity : m_capacity * 2;
+    JSCell** newRoots = static_cast<JSCell**>(OSAllocator::reserveAndCommit(newCapacity * sizeof(JSCell*)));
+    memcpy(newRoots, m_roots, m_size * sizeof(JSCell*));
+    if (m_roots != m_inlineRoots)
+        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
+    m_capacity = newCapacity;
+    m_roots = newRoots;
+}
+
+class DummyMarkHook {
+public:
+    void mark(void*) { }
+};
+
+template<typename MarkHook>
+inline void ConservativeRoots::genericAddPointer(void* p, TinyBloomFilter filter, MarkHook& markHook)
+{
+    markHook.mark(p);
+    
+    MarkedBlock* candidate = MarkedBlock::blockFor(p);
+    if (filter.ruleOut(reinterpret_cast<Bits>(candidate))) {
+        ASSERT(!candidate || !m_blocks->set().contains(candidate));
+        return;
+    }
+
+    if (!MarkedBlock::isAtomAligned(p))
+        return;
+
+    if (!m_blocks->set().contains(candidate))
+        return;
+
+    if (!candidate->isLiveCell(p))
+        return;
+
+    if (m_size == m_capacity)
+        grow();
+
+    m_roots[m_size++] = static_cast<JSCell*>(p);
+}
+
+template<typename MarkHook>
+void ConservativeRoots::genericAddSpan(void* begin, void* end, MarkHook& markHook)
+{
+    ASSERT(begin <= end);
+    ASSERT((static_cast<char*>(end) - static_cast<char*>(begin)) < 0x1000000);
+    ASSERT(isPointerAligned(begin));
+    ASSERT(isPointerAligned(end));
+
+    TinyBloomFilter filter = m_blocks->filter(); // Make a local copy of filter to show the compiler it won't alias, and can be register-allocated.
+    for (char** it = static_cast<char**>(begin); it != static_cast<char**>(end); ++it)
+        genericAddPointer(*it, filter, markHook);
+}
+
+void ConservativeRoots::add(void* begin, void* end)
+{
+    DummyMarkHook dummyMarkHook;
+    genericAddSpan(begin, end, dummyMarkHook);
+}
+
+void ConservativeRoots::add(void* begin, void* end, DFGCodeBlocks& dfgCodeBlocks)
+{
+    genericAddSpan(begin, end, dfgCodeBlocks);
+}
+
+} // namespace JSC