--- /dev/null
+/*
+ * Copyright (C) 2009, 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. ``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
+ * 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.
+ */
+
+#ifndef MarkStack_h
+#define MarkStack_h
+
+#include "HandleTypes.h"
+#include "JSValue.h"
+#include "Register.h"
+#include <wtf/HashSet.h>
+#include <wtf/Vector.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/OSAllocator.h>
+
+namespace JSC {
+
+ class ConservativeRoots;
+ class JSGlobalData;
+ class Register;
+ template<typename T> class WriteBarrierBase;
+ template<typename T> class JITWriteBarrier;
+
+ enum MarkSetProperties { MayContainNullValues, NoNullValues };
+
+ class MarkStack {
+ WTF_MAKE_NONCOPYABLE(MarkStack);
+ public:
+ MarkStack(void* jsArrayVPtr)
+ : m_jsArrayVPtr(jsArrayVPtr)
+ , m_shouldUnlinkCalls(false)
+#if !ASSERT_DISABLED
+ , m_isCheckingForDefaultMarkViolation(false)
+ , m_isDraining(false)
+#endif
+ {
+ }
+
+ ~MarkStack()
+ {
+ ASSERT(m_markSets.isEmpty());
+ ASSERT(m_values.isEmpty());
+ }
+
+ template<typename T> inline void append(JITWriteBarrier<T>*);
+ template<typename T> inline void append(WriteBarrierBase<T>*);
+ inline void appendValues(WriteBarrierBase<Unknown>*, size_t count, MarkSetProperties = NoNullValues);
+
+ void append(ConservativeRoots&);
+
+ bool addOpaqueRoot(void* root) { return m_opaqueRoots.add(root).second; }
+ bool containsOpaqueRoot(void* root) { return m_opaqueRoots.contains(root); }
+ int opaqueRootCount() { return m_opaqueRoots.size(); }
+
+ void drain();
+ void reset();
+
+ bool shouldUnlinkCalls() const { return m_shouldUnlinkCalls; }
+ void setShouldUnlinkCalls(bool shouldUnlinkCalls) { m_shouldUnlinkCalls = shouldUnlinkCalls; }
+
+ private:
+ friend class HeapRootVisitor; // Allowed to mark a JSValue* or JSCell** directly.
+
+#if ENABLE(GC_VALIDATION)
+ static void validateSet(JSValue*, size_t);
+ static void validateValue(JSValue);
+#endif
+
+ void append(JSValue*);
+ void append(JSValue*, size_t count);
+ void append(JSCell**);
+
+ void internalAppend(JSCell*);
+ void internalAppend(JSValue);
+ void visitChildren(JSCell*);
+
+ struct MarkSet {
+ MarkSet(JSValue* values, JSValue* end, MarkSetProperties properties)
+ : m_values(values)
+ , m_end(end)
+ , m_properties(properties)
+ {
+ ASSERT(values);
+ }
+ JSValue* m_values;
+ JSValue* m_end;
+ MarkSetProperties m_properties;
+ };
+
+ static void* allocateStack(size_t size) { return OSAllocator::reserveAndCommit(size); }
+ static void releaseStack(void* addr, size_t size) { OSAllocator::decommitAndRelease(addr, size); }
+
+ static void initializePagesize();
+ static size_t pageSize()
+ {
+ if (!s_pageSize)
+ initializePagesize();
+ return s_pageSize;
+ }
+
+ template<typename T> struct MarkStackArray {
+ MarkStackArray()
+ : m_top(0)
+ , m_allocated(MarkStack::pageSize())
+ , m_capacity(m_allocated / sizeof(T))
+ {
+ m_data = reinterpret_cast<T*>(allocateStack(m_allocated));
+ }
+
+ ~MarkStackArray()
+ {
+ releaseStack(m_data, m_allocated);
+ }
+
+ void expand()
+ {
+ size_t oldAllocation = m_allocated;
+ m_allocated *= 2;
+ m_capacity = m_allocated / sizeof(T);
+ void* newData = allocateStack(m_allocated);
+ memcpy(newData, m_data, oldAllocation);
+ releaseStack(m_data, oldAllocation);
+ m_data = reinterpret_cast<T*>(newData);
+ }
+
+ inline void append(const T& v)
+ {
+ if (m_top == m_capacity)
+ expand();
+ m_data[m_top++] = v;
+ }
+
+ inline T removeLast()
+ {
+ ASSERT(m_top);
+ return m_data[--m_top];
+ }
+
+ inline T& last()
+ {
+ ASSERT(m_top);
+ return m_data[m_top - 1];
+ }
+
+ inline bool isEmpty()
+ {
+ return m_top == 0;
+ }
+
+ inline size_t size() { return m_top; }
+
+ inline void shrinkAllocation(size_t size)
+ {
+ ASSERT(size <= m_allocated);
+ ASSERT(0 == (size % MarkStack::pageSize()));
+ if (size == m_allocated)
+ return;
+#if OS(WINDOWS) || OS(SYMBIAN) || PLATFORM(BREWMP)
+ // We cannot release a part of a region with VirtualFree. To get around this,
+ // we'll release the entire region and reallocate the size that we want.
+ releaseStack(m_data, m_allocated);
+ m_data = reinterpret_cast<T*>(allocateStack(size));
+#else
+ releaseStack(reinterpret_cast<char*>(m_data) + size, m_allocated - size);
+#endif
+ m_allocated = size;
+ m_capacity = m_allocated / sizeof(T);
+ }
+
+ private:
+ size_t m_top;
+ size_t m_allocated;
+ size_t m_capacity;
+ T* m_data;
+ };
+
+ void* m_jsArrayVPtr;
+ MarkStackArray<MarkSet> m_markSets;
+ MarkStackArray<JSCell*> m_values;
+ static size_t s_pageSize;
+ HashSet<void*> m_opaqueRoots; // Handle-owning data structures not visible to the garbage collector.
+ bool m_shouldUnlinkCalls;
+
+#if !ASSERT_DISABLED
+ public:
+ bool m_isCheckingForDefaultMarkViolation;
+ bool m_isDraining;
+#endif
+ };
+
+ typedef MarkStack SlotVisitor;
+
+ inline void MarkStack::append(JSValue* slot, size_t count)
+ {
+ if (!count)
+ return;
+#if ENABLE(GC_VALIDATION)
+ validateSet(slot, count);
+#endif
+ m_markSets.append(MarkSet(slot, slot + count, NoNullValues));
+ }
+
+ ALWAYS_INLINE void MarkStack::append(JSValue* value)
+ {
+ ASSERT(value);
+ internalAppend(*value);
+ }
+
+ ALWAYS_INLINE void MarkStack::append(JSCell** value)
+ {
+ ASSERT(value);
+ internalAppend(*value);
+ }
+
+ ALWAYS_INLINE void MarkStack::internalAppend(JSValue value)
+ {
+ ASSERT(value);
+#if ENABLE(GC_VALIDATION)
+ validateValue(value);
+#endif
+ if (value.isCell())
+ internalAppend(value.asCell());
+ }
+
+ // Privileged class for marking JSValues directly. It is only safe to use
+ // this class to mark direct heap roots that are marked during every GC pass.
+ // All other references should be wrapped in WriteBarriers and marked through
+ // the MarkStack.
+ class HeapRootVisitor {
+ private:
+ friend class Heap;
+ HeapRootVisitor(SlotVisitor&);
+
+ public:
+ void mark(JSValue*);
+ void mark(JSValue*, size_t);
+ void mark(JSString**);
+ void mark(JSCell**);
+
+ SlotVisitor& visitor();
+
+ private:
+ SlotVisitor& m_visitor;
+ };
+
+ inline HeapRootVisitor::HeapRootVisitor(SlotVisitor& visitor)
+ : m_visitor(visitor)
+ {
+ }
+
+ inline void HeapRootVisitor::mark(JSValue* slot)
+ {
+ m_visitor.append(slot);
+ }
+
+ inline void HeapRootVisitor::mark(JSValue* slot, size_t count)
+ {
+ m_visitor.append(slot, count);
+ }
+
+ inline void HeapRootVisitor::mark(JSString** slot)
+ {
+ m_visitor.append(reinterpret_cast<JSCell**>(slot));
+ }
+
+ inline void HeapRootVisitor::mark(JSCell** slot)
+ {
+ m_visitor.append(slot);
+ }
+
+ inline SlotVisitor& HeapRootVisitor::visitor()
+ {
+ return m_visitor;
+ }
+
+} // namespace JSC
+
+#endif
projects / apple / javascriptcore.git / blobdiff