Source/JavaScriptCore/dfg/DFGAbstractHeap.h - WebKit - Git at Google

 /*
  * Copyright (C) 2013-2015 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 DFGAbstractHeap_h
 #define DFGAbstractHeap_h

 #if ENABLE(DFG_JIT)

 #include "VirtualRegister.h"
 #include <wtf/HashMap.h>
 #include <wtf/PrintStream.h>

 namespace JSC { namespace DFG {

 // Implements a four-level type hierarchy:
 // - World is the supertype of all of the things.
 // - Stack with a TOP payload is a direct subtype of World
 // - Stack with a non-TOP payload is a direct subtype of Stack with a TOP payload.
 // - Heap is a direct subtype of World.
 // - SideState is a direct subtype of World.
 // - Any other kind with TOP payload is the direct subtype of Heap.
 // - Any other kind with non-TOP payload is the direct subtype of the same kind with a TOP payload.

 #define FOR_EACH_ABSTRACT_HEAP_KIND(macro) \
     macro(InvalidAbstractHeap) \
     macro(World) \
     macro(Stack) \
     macro(Heap) \
     macro(Butterfly_publicLength) \
     macro(Butterfly_vectorLength) \
     macro(GetterSetter_getter) \
     macro(GetterSetter_setter) \
     macro(JSCell_structureID) \
     macro(JSCell_indexingType) \
     macro(JSCell_typeInfoFlags) \
     macro(JSCell_typeInfoType) \
     macro(JSObject_butterfly) \
     macro(JSPropertyNameEnumerator_cachedPropertyNames) \
     macro(NamedProperties) \
     macro(IndexedInt32Properties) \
     macro(IndexedDoubleProperties) \
     macro(IndexedContiguousProperties) \
     macro(IndexedArrayStorageProperties) \
     macro(ArrayStorageProperties) \
     macro(DirectArgumentsProperties) \
     macro(ScopeProperties) \
     macro(TypedArrayProperties) \
     macro(HeapObjectCount) /* Used to reflect the fact that some allocations reveal object identity */\
     macro(RegExpState) \
     macro(InternalState) \
     macro(Absolute) \
     /* Use this for writes only, to indicate that this may fire watchpoints. Usually this is never directly written but instead we test to see if a node clobbers this; it just so happens that you have to write world to clobber it. */\
     macro(Watchpoint_fire) \
     /* Use these for reads only, just to indicate that if the world got clobbered, then this operation will not work. */\
     macro(MiscFields) \
     /* Use this for writes only, just to indicate that hoisting the node is invalid. This works because we don't hoist anything that has any side effects at all. */\
     macro(SideState)

 enum AbstractHeapKind {
 #define ABSTRACT_HEAP_DECLARATION(name) name,
     FOR_EACH_ABSTRACT_HEAP_KIND(ABSTRACT_HEAP_DECLARATION)
 #undef ABSTRACT_HEAP_DECLARATION
 };

 class AbstractHeap {
 public:
     class Payload {
     public:
         Payload()
             : m_isTop(false)
             , m_value(0)
         {
         }

         Payload(bool isTop, int64_t value)
             : m_isTop(isTop)
             , m_value(value)
         {
             ASSERT(!(isTop && value));
         }

         Payload(int64_t value)
             : m_isTop(false)
             , m_value(value)
         {
         }

         Payload(const void* pointer)
             : m_isTop(false)
             , m_value(bitwise_cast<intptr_t>(pointer))
         {
         }

         Payload(VirtualRegister operand)
             : m_isTop(false)
             , m_value(operand.offset())
         {
         }

         static Payload top() { return Payload(true, 0); }

         bool isTop() const { return m_isTop; }
         int64_t value() const
         {
             ASSERT(!isTop());
             return valueImpl();
         }
         int64_t valueImpl() const
         {
             return m_value;
         }

         int32_t value32() const
         {
             return static_cast<int32_t>(value());
         }

         bool operator==(const Payload& other) const
         {
             return m_isTop == other.m_isTop
                 && m_value == other.m_value;
         }

         bool operator!=(const Payload& other) const
         {
             return !(*this == other);
         }

         bool operator<(const Payload& other) const
         {
             if (isTop())
                 return !other.isTop();
             if (other.isTop())
                 return false;
             return value() < other.value();
         }

         bool isDisjoint(const Payload& other) const
         {
             if (isTop())
                 return false;
             if (other.isTop())
                 return false;
             return m_value != other.m_value;
         }

         bool overlaps(const Payload& other) const
         {
             return !isDisjoint(other);
         }

         void dump(PrintStream&) const;

     private:
         bool m_isTop;
         int64_t m_value;
     };

     AbstractHeap()
     {
         m_value = encode(InvalidAbstractHeap, Payload());
     }

     AbstractHeap(AbstractHeapKind kind)
     {
         ASSERT(kind != InvalidAbstractHeap);
         m_value = encode(kind, Payload::top());
     }

     AbstractHeap(AbstractHeapKind kind, Payload payload)
     {
         ASSERT(kind != InvalidAbstractHeap && kind != World && kind != Heap && kind != SideState);
         m_value = encode(kind, payload);
     }

     AbstractHeap(WTF::HashTableDeletedValueType)
     {
         m_value = encode(InvalidAbstractHeap, Payload::top());
     }

     bool operator!() const { return kind() == InvalidAbstractHeap && !payloadImpl().isTop(); }

     AbstractHeapKind kind() const { return static_cast<AbstractHeapKind>(m_value & ((1 << topShift) - 1)); }
     Payload payload() const
     {
         ASSERT(kind() != World && kind() != InvalidAbstractHeap);
         return payloadImpl();
     }

     AbstractHeap supertype() const
     {
         ASSERT(kind() != InvalidAbstractHeap);
         switch (kind()) {
         case World:
             return AbstractHeap();
         case Heap:
         case SideState:
             return World;
         default:
             if (payload().isTop()) {
                 if (kind() == Stack)
                     return World;
                 return Heap;
             }
             return AbstractHeap(kind());
         }
     }

     bool isStrictSubtypeOf(const AbstractHeap& other) const
     {
         AbstractHeap current = *this;
         while (current.kind() != World) {
             current = current.supertype();
             if (current == other)
                 return true;
         }
         return false;
     }

     bool isSubtypeOf(const AbstractHeap& other) const
     {
         return *this == other || isStrictSubtypeOf(other);
     }

     bool overlaps(const AbstractHeap& other) const
     {
         return *this == other || isStrictSubtypeOf(other) || other.isStrictSubtypeOf(*this);
     }

     bool isDisjoint(const AbstractHeap& other) const
     {
         return !overlaps(other);
     }

     unsigned hash() const
     {
         return WTF::IntHash<int64_t>::hash(m_value);
     }

     bool operator==(const AbstractHeap& other) const
     {
         return m_value == other.m_value;
     }

     bool operator!=(const AbstractHeap& other) const
     {
         return !(*this == other);
     }

     bool operator<(const AbstractHeap& other) const
     {
         if (kind() != other.kind())
             return kind() < other.kind();
         return payload() < other.payload();
     }

     bool isHashTableDeletedValue() const
     {
         return kind() == InvalidAbstractHeap && payloadImpl().isTop();
     }

     void dump(PrintStream& out) const;

 private:
     static const unsigned valueShift = 15;
     static const unsigned topShift = 14;

     Payload payloadImpl() const
     {
         return Payload((m_value >> topShift) & 1, m_value >> valueShift);
     }

     static int64_t encode(AbstractHeapKind kind, Payload payload)
     {
         int64_t kindAsInt = static_cast<int64_t>(kind);
         ASSERT(kindAsInt < (1 << topShift));
         return kindAsInt | (payload.isTop() << topShift) | (payload.valueImpl() << valueShift);
     }

     // The layout of the value is:
     // Low 14 bits: the Kind
     // 15th bit: whether or not the payload is TOP.
     // The upper bits: the payload.value().
     int64_t m_value;
 };

 struct AbstractHeapHash {
     static unsigned hash(const AbstractHeap& key) { return key.hash(); }
     static bool equal(const AbstractHeap& a, const AbstractHeap& b) { return a == b; }
     static const bool safeToCompareToEmptyOrDeleted = true;
 };

 } } // namespace JSC::DFG

 namespace WTF {

 void printInternal(PrintStream&, JSC::DFG::AbstractHeapKind);

 template<typename T> struct DefaultHash;
 template<> struct DefaultHash<JSC::DFG::AbstractHeap> {
     typedef JSC::DFG::AbstractHeapHash Hash;
 };

 template<typename T> struct HashTraits;
 template<> struct HashTraits<JSC::DFG::AbstractHeap> : SimpleClassHashTraits<JSC::DFG::AbstractHeap> { };

 } // namespace WTF

 #endif // ENABLE(DFG_JIT)

 #endif // DFGAbstractHeap_h
	/*
	* Copyright (C) 2013-2015 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 DFGAbstractHeap_h
	#define DFGAbstractHeap_h

	#if ENABLE(DFG_JIT)

	#include "VirtualRegister.h"
	#include <wtf/HashMap.h>
	#include <wtf/PrintStream.h>

	namespace JSC { namespace DFG {

	// Implements a four-level type hierarchy:
	// - World is the supertype of all of the things.
	// - Stack with a TOP payload is a direct subtype of World
	// - Stack with a non-TOP payload is a direct subtype of Stack with a TOP payload.
	// - Heap is a direct subtype of World.
	// - SideState is a direct subtype of World.
	// - Any other kind with TOP payload is the direct subtype of Heap.
	// - Any other kind with non-TOP payload is the direct subtype of the same kind with a TOP payload.

	#define FOR_EACH_ABSTRACT_HEAP_KIND(macro) \
	macro(InvalidAbstractHeap) \
	macro(World) \
	macro(Stack) \
	macro(Heap) \
	macro(Butterfly_publicLength) \
	macro(Butterfly_vectorLength) \
	macro(GetterSetter_getter) \
	macro(GetterSetter_setter) \
	macro(JSCell_structureID) \
	macro(JSCell_indexingType) \
	macro(JSCell_typeInfoFlags) \
	macro(JSCell_typeInfoType) \
	macro(JSObject_butterfly) \
	macro(JSPropertyNameEnumerator_cachedPropertyNames) \
	macro(NamedProperties) \
	macro(IndexedInt32Properties) \
	macro(IndexedDoubleProperties) \
	macro(IndexedContiguousProperties) \
	macro(IndexedArrayStorageProperties) \
	macro(ArrayStorageProperties) \
	macro(DirectArgumentsProperties) \
	macro(ScopeProperties) \
	macro(TypedArrayProperties) \
	macro(HeapObjectCount) /* Used to reflect the fact that some allocations reveal object identity */\
	macro(RegExpState) \
	macro(InternalState) \
	macro(Absolute) \
	/* Use this for writes only, to indicate that this may fire watchpoints. Usually this is never directly written but instead we test to see if a node clobbers this; it just so happens that you have to write world to clobber it. */\
	macro(Watchpoint_fire) \
	/* Use these for reads only, just to indicate that if the world got clobbered, then this operation will not work. */\
	macro(MiscFields) \
	/* Use this for writes only, just to indicate that hoisting the node is invalid. This works because we don't hoist anything that has any side effects at all. */\
	macro(SideState)

	enum AbstractHeapKind {
	#define ABSTRACT_HEAP_DECLARATION(name) name,
	FOR_EACH_ABSTRACT_HEAP_KIND(ABSTRACT_HEAP_DECLARATION)
	#undef ABSTRACT_HEAP_DECLARATION
	};

	class AbstractHeap {
	public:
	class Payload {
	public:
	Payload()
	: m_isTop(false)
	, m_value(0)
	{
	}

	Payload(bool isTop, int64_t value)
	: m_isTop(isTop)
	, m_value(value)
	{
	ASSERT(!(isTop && value));
	}

	Payload(int64_t value)
	: m_isTop(false)
	, m_value(value)
	{
	}

	Payload(const void* pointer)
	: m_isTop(false)
	, m_value(bitwise_cast<intptr_t>(pointer))
	{
	}

	Payload(VirtualRegister operand)
	: m_isTop(false)
	, m_value(operand.offset())
	{
	}

	static Payload top() { return Payload(true, 0); }

	bool isTop() const { return m_isTop; }
	int64_t value() const
	{
	ASSERT(!isTop());
	return valueImpl();
	}
	int64_t valueImpl() const
	{
	return m_value;
	}

	int32_t value32() const
	{
	return static_cast<int32_t>(value());
	}

	bool operator==(const Payload& other) const
	{
	return m_isTop == other.m_isTop
	&& m_value == other.m_value;
	}

	bool operator!=(const Payload& other) const
	{
	return !(*this == other);
	}

	bool operator<(const Payload& other) const
	{
	if (isTop())
	return !other.isTop();
	if (other.isTop())
	return false;
	return value() < other.value();
	}

	bool isDisjoint(const Payload& other) const
	{
	if (isTop())
	return false;
	if (other.isTop())
	return false;
	return m_value != other.m_value;
	}

	bool overlaps(const Payload& other) const
	{
	return !isDisjoint(other);
	}

	void dump(PrintStream&) const;

	private:
	bool m_isTop;
	int64_t m_value;
	};

	AbstractHeap()
	{
	m_value = encode(InvalidAbstractHeap, Payload());
	}

	AbstractHeap(AbstractHeapKind kind)
	{
	ASSERT(kind != InvalidAbstractHeap);
	m_value = encode(kind, Payload::top());
	}

	AbstractHeap(AbstractHeapKind kind, Payload payload)
	{
	ASSERT(kind != InvalidAbstractHeap && kind != World && kind != Heap && kind != SideState);
	m_value = encode(kind, payload);
	}

	AbstractHeap(WTF::HashTableDeletedValueType)
	{
	m_value = encode(InvalidAbstractHeap, Payload::top());
	}

	bool operator!() const { return kind() == InvalidAbstractHeap && !payloadImpl().isTop(); }

	AbstractHeapKind kind() const { return static_cast<AbstractHeapKind>(m_value & ((1 << topShift) - 1)); }
	Payload payload() const
	{
	ASSERT(kind() != World && kind() != InvalidAbstractHeap);
	return payloadImpl();
	}

	AbstractHeap supertype() const
	{
	ASSERT(kind() != InvalidAbstractHeap);
	switch (kind()) {
	case World:
	return AbstractHeap();
	case Heap:
	case SideState:
	return World;
	default:
	if (payload().isTop()) {
	if (kind() == Stack)
	return World;
	return Heap;
	}
	return AbstractHeap(kind());
	}
	}

	bool isStrictSubtypeOf(const AbstractHeap& other) const
	{
	AbstractHeap current = *this;
	while (current.kind() != World) {
	current = current.supertype();
	if (current == other)
	return true;
	}
	return false;
	}

	bool isSubtypeOf(const AbstractHeap& other) const
	{
	return *this == other \|\| isStrictSubtypeOf(other);
	}

	bool overlaps(const AbstractHeap& other) const
	{
	return this == other \|\| isStrictSubtypeOf(other) \|\| other.isStrictSubtypeOf(this);
	}

	bool isDisjoint(const AbstractHeap& other) const
	{
	return !overlaps(other);
	}

	unsigned hash() const
	{
	return WTF::IntHash<int64_t>::hash(m_value);
	}

	bool operator==(const AbstractHeap& other) const
	{
	return m_value == other.m_value;
	}

	bool operator!=(const AbstractHeap& other) const
	{
	return !(*this == other);
	}

	bool operator<(const AbstractHeap& other) const
	{
	if (kind() != other.kind())
	return kind() < other.kind();
	return payload() < other.payload();
	}

	bool isHashTableDeletedValue() const
	{
	return kind() == InvalidAbstractHeap && payloadImpl().isTop();
	}

	void dump(PrintStream& out) const;

	private:
	static const unsigned valueShift = 15;
	static const unsigned topShift = 14;

	Payload payloadImpl() const
	{
	return Payload((m_value >> topShift) & 1, m_value >> valueShift);
	}

	static int64_t encode(AbstractHeapKind kind, Payload payload)
	{
	int64_t kindAsInt = static_cast<int64_t>(kind);
	ASSERT(kindAsInt < (1 << topShift));
	return kindAsInt \| (payload.isTop() << topShift) \| (payload.valueImpl() << valueShift);
	}

	// The layout of the value is:
	// Low 14 bits: the Kind
	// 15th bit: whether or not the payload is TOP.
	// The upper bits: the payload.value().
	int64_t m_value;
	};

	struct AbstractHeapHash {
	static unsigned hash(const AbstractHeap& key) { return key.hash(); }
	static bool equal(const AbstractHeap& a, const AbstractHeap& b) { return a == b; }
	static const bool safeToCompareToEmptyOrDeleted = true;
	};

	} } // namespace JSC::DFG

	namespace WTF {

	void printInternal(PrintStream&, JSC::DFG::AbstractHeapKind);

	template<typename T> struct DefaultHash;
	template<> struct DefaultHash<JSC::DFG::AbstractHeap> {
	typedef JSC::DFG::AbstractHeapHash Hash;
	};

	template<typename T> struct HashTraits;
	template<> struct HashTraits<JSC::DFG::AbstractHeap> : SimpleClassHashTraits<JSC::DFG::AbstractHeap> { };

	} // namespace WTF

	#endif // ENABLE(DFG_JIT)

	#endif // DFGAbstractHeap_h