Source/JavaScriptCore/bytecode/InstructionStream.h - WebKit - Git at Google

 /*
  * Copyright (C) 2018 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.
  */


 #pragma once

 #include "BytecodeIndex.h"
 #include "Instruction.h"
 #include <wtf/Vector.h>

 namespace JSC {

 DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(InstructionStream);

 class InstructionStream {
     WTF_MAKE_FAST_ALLOCATED;

     using InstructionBuffer = Vector<uint8_t, 0, UnsafeVectorOverflow, 16, InstructionStreamMalloc>;

     friend class InstructionStreamWriter;
     friend class CachedInstructionStream;
 public:
     size_t sizeInBytes() const;

     using Offset = unsigned;

 private:
     template<class InstructionBuffer>
     class BaseRef {
         WTF_MAKE_FAST_ALLOCATED;

         friend class InstructionStream;

     public:
         BaseRef(const BaseRef<InstructionBuffer>& other)
             : m_instructions(other.m_instructions)
             ,  m_index(other.m_index)
         { }

         void operator=(const BaseRef<InstructionBuffer>& other)
         {
             m_instructions = other.m_instructions;
             m_index = other.m_index;
         }

         inline const Instruction* operator->() const { return unwrap(); }
         inline const Instruction* ptr() const { return unwrap(); }

         bool operator!=(const BaseRef<InstructionBuffer>& other) const
         {
             return &m_instructions != &other.m_instructions || m_index != other.m_index;
         }

         BaseRef next() const
         {
             return BaseRef { m_instructions, m_index + ptr()->size() };
         }

         inline Offset offset() const { return m_index; }
         inline BytecodeIndex index() const { return BytecodeIndex(offset()); }

         bool isValid() const
         {
             return m_index < m_instructions.size();
         }

     private:
         inline const Instruction* unwrap() const { return reinterpret_cast<const Instruction*>(&m_instructions[m_index]); }

     protected:
         BaseRef(InstructionBuffer& instructions, size_t index)
             : m_instructions(instructions)
             , m_index(index)
         { }

         InstructionBuffer& m_instructions;
         Offset m_index;
     };

 public:
     using Ref = BaseRef<const InstructionBuffer>;

     class MutableRef : public BaseRef<InstructionBuffer> {
         friend class InstructionStreamWriter;

     protected:
         using BaseRef<InstructionBuffer>::BaseRef;

     public:
         Ref freeze() const  { return Ref { m_instructions, m_index }; }
         inline Instruction* operator->() { return unwrap(); }
         inline const Instruction* operator->() const { return unwrap(); }
         inline Instruction* ptr() { return unwrap(); }
         inline const Instruction* ptr() const { return unwrap(); }
         inline operator Ref()
         {
             return Ref { m_instructions, m_index };
         }

     private:
         inline Instruction* unwrap() { return reinterpret_cast<Instruction*>(&m_instructions[m_index]); }
         inline const Instruction* unwrap() const { return reinterpret_cast<const Instruction*>(&m_instructions[m_index]); }
     };

 private:
     class iterator : public Ref {
         friend class InstructionStream;

     public:
         using Ref::Ref;

         Ref& operator*()
         {
             return *this;
         }

         iterator& operator+=(size_t size)
         {
             m_index += size;
             return *this;
         }

         iterator& operator++()
         {
             return *this += ptr()->size();
         }
     };

 public:
     inline iterator begin() const
     {
         return iterator { m_instructions, 0 };
     }

     inline iterator end() const
     {
         return iterator { m_instructions, m_instructions.size() };
     }

     inline const Ref at(BytecodeIndex index) const { return at(index.offset()); }
     inline const Ref at(Offset offset) const
     {
         ASSERT(offset < m_instructions.size());
         return Ref { m_instructions, offset };
     }

     inline size_t size() const
     {
         return m_instructions.size();
     }

     const void* rawPointer() const
     {
         return m_instructions.data();
     }

     bool contains(Instruction *) const;

 protected:
     explicit InstructionStream(InstructionBuffer&&);

     InstructionBuffer m_instructions;
 };

 class InstructionStreamWriter : public InstructionStream {
     friend class BytecodeRewriter;
 public:
     InstructionStreamWriter()
         : InstructionStream({ })
     { }

     inline MutableRef ref(Offset offset)
     {
         ASSERT(offset < m_instructions.size());
         return MutableRef { m_instructions, offset };
     }

     void seek(unsigned position)
     {
         ASSERT(position <= m_instructions.size());
         m_position = position;
     }

     unsigned position()
     {
         return m_position;
     }

     void write(uint8_t byte)
     {
         ASSERT(!m_finalized);
         if (m_position < m_instructions.size())
             m_instructions[m_position++] = byte;
         else {
             m_instructions.append(byte);
             m_position++;
         }
     }

     void write(uint16_t h)
     {
         ASSERT(!m_finalized);
         uint8_t bytes[2];
         std::memcpy(bytes, &h, sizeof(h));

         // Though not always obvious, we don't have to invert the order of the
         // bytes written here for CPU(BIG_ENDIAN). This is because the incoming
         // i value is already ordered in big endian on CPU(BIG_EDNDIAN) platforms.
         write(bytes[0]);
         write(bytes[1]);
     }

     void write(uint32_t i)
     {
         ASSERT(!m_finalized);
         uint8_t bytes[4];
         std::memcpy(bytes, &i, sizeof(i));

         // Though not always obvious, we don't have to invert the order of the
         // bytes written here for CPU(BIG_ENDIAN). This is because the incoming
         // i value is already ordered in big endian on CPU(BIG_EDNDIAN) platforms.
         write(bytes[0]);
         write(bytes[1]);
         write(bytes[2]);
         write(bytes[3]);
     }

     void rewind(MutableRef& ref)
     {
         ASSERT(ref.offset() < m_instructions.size());
         m_instructions.shrink(ref.offset());
         m_position = ref.offset();
     }

     std::unique_ptr<InstructionStream> finalize()
     {
         m_finalized = true;
         m_instructions.shrinkToFit();
         return std::unique_ptr<InstructionStream> { new InstructionStream(WTFMove(m_instructions)) };
     }

     MutableRef ref()
     {
         return MutableRef { m_instructions, m_position };
     }

     void swap(InstructionStreamWriter& other)
     {
         std::swap(m_finalized, other.m_finalized);
         std::swap(m_position, other.m_position);
         m_instructions.swap(other.m_instructions);
     }

 private:
     class iterator : public MutableRef {
         friend class InstructionStreamWriter;

     protected:
         using MutableRef::MutableRef;

     public:
         MutableRef& operator*()
         {
             return *this;
         }

         iterator& operator+=(size_t size)
         {
             m_index += size;
             return *this;
         }

         iterator& operator++()
         {
             return *this += ptr()->size();
         }
     };

 public:
     iterator begin()
     {
         return iterator { m_instructions, 0 };
     }

     iterator end()
     {
         return iterator { m_instructions, m_instructions.size() };
     }

 private:
     unsigned m_position { 0 };
     bool m_finalized { false };
 };


 } // namespace JSC
	/*
	* Copyright (C) 2018 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.
	*/


	#pragma once

	#include "BytecodeIndex.h"
	#include "Instruction.h"
	#include <wtf/Vector.h>

	namespace JSC {

	DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(InstructionStream);

	class InstructionStream {
	WTF_MAKE_FAST_ALLOCATED;

	using InstructionBuffer = Vector<uint8_t, 0, UnsafeVectorOverflow, 16, InstructionStreamMalloc>;

	friend class InstructionStreamWriter;
	friend class CachedInstructionStream;
	public:
	size_t sizeInBytes() const;

	using Offset = unsigned;

	private:
	template<class InstructionBuffer>
	class BaseRef {
	WTF_MAKE_FAST_ALLOCATED;

	friend class InstructionStream;

	public:
	BaseRef(const BaseRef<InstructionBuffer>& other)
	: m_instructions(other.m_instructions)
	, m_index(other.m_index)
	{ }

	void operator=(const BaseRef<InstructionBuffer>& other)
	{
	m_instructions = other.m_instructions;
	m_index = other.m_index;
	}

	inline const Instruction* operator->() const { return unwrap(); }
	inline const Instruction* ptr() const { return unwrap(); }

	bool operator!=(const BaseRef<InstructionBuffer>& other) const
	{
	return &m_instructions != &other.m_instructions \|\| m_index != other.m_index;
	}

	BaseRef next() const
	{
	return BaseRef { m_instructions, m_index + ptr()->size() };
	}

	inline Offset offset() const { return m_index; }
	inline BytecodeIndex index() const { return BytecodeIndex(offset()); }

	bool isValid() const
	{
	return m_index < m_instructions.size();
	}

	private:
	inline const Instruction* unwrap() const { return reinterpret_cast<const Instruction*>(&m_instructions[m_index]); }

	protected:
	BaseRef(InstructionBuffer& instructions, size_t index)
	: m_instructions(instructions)
	, m_index(index)
	{ }

	InstructionBuffer& m_instructions;
	Offset m_index;
	};

	public:
	using Ref = BaseRef<const InstructionBuffer>;

	class MutableRef : public BaseRef<InstructionBuffer> {
	friend class InstructionStreamWriter;

	protected:
	using BaseRef<InstructionBuffer>::BaseRef;

	public:
	Ref freeze() const { return Ref { m_instructions, m_index }; }
	inline Instruction* operator->() { return unwrap(); }
	inline const Instruction* operator->() const { return unwrap(); }
	inline Instruction* ptr() { return unwrap(); }
	inline const Instruction* ptr() const { return unwrap(); }
	inline operator Ref()
	{
	return Ref { m_instructions, m_index };
	}

	private:
	inline Instruction* unwrap() { return reinterpret_cast<Instruction*>(&m_instructions[m_index]); }
	inline const Instruction* unwrap() const { return reinterpret_cast<const Instruction*>(&m_instructions[m_index]); }
	};

	private:
	class iterator : public Ref {
	friend class InstructionStream;

	public:
	using Ref::Ref;

	Ref& operator*()
	{
	return *this;
	}

	iterator& operator+=(size_t size)
	{
	m_index += size;
	return *this;
	}

	iterator& operator++()
	{
	return *this += ptr()->size();
	}
	};

	public:
	inline iterator begin() const
	{
	return iterator { m_instructions, 0 };
	}

	inline iterator end() const
	{
	return iterator { m_instructions, m_instructions.size() };
	}

	inline const Ref at(BytecodeIndex index) const { return at(index.offset()); }
	inline const Ref at(Offset offset) const
	{
	ASSERT(offset < m_instructions.size());
	return Ref { m_instructions, offset };
	}

	inline size_t size() const
	{
	return m_instructions.size();
	}

	const void* rawPointer() const
	{
	return m_instructions.data();
	}

	bool contains(Instruction *) const;

	protected:
	explicit InstructionStream(InstructionBuffer&&);

	InstructionBuffer m_instructions;
	};

	class InstructionStreamWriter : public InstructionStream {
	friend class BytecodeRewriter;
	public:
	InstructionStreamWriter()
	: InstructionStream({ })
	{ }

	inline MutableRef ref(Offset offset)
	{
	ASSERT(offset < m_instructions.size());
	return MutableRef { m_instructions, offset };
	}

	void seek(unsigned position)
	{
	ASSERT(position <= m_instructions.size());
	m_position = position;
	}

	unsigned position()
	{
	return m_position;
	}

	void write(uint8_t byte)
	{
	ASSERT(!m_finalized);
	if (m_position < m_instructions.size())
	m_instructions[m_position++] = byte;
	else {
	m_instructions.append(byte);
	m_position++;
	}
	}

	void write(uint16_t h)
	{
	ASSERT(!m_finalized);
	uint8_t bytes[2];
	std::memcpy(bytes, &h, sizeof(h));

	// Though not always obvious, we don't have to invert the order of the
	// bytes written here for CPU(BIG_ENDIAN). This is because the incoming
	// i value is already ordered in big endian on CPU(BIG_EDNDIAN) platforms.
	write(bytes[0]);
	write(bytes[1]);
	}

	void write(uint32_t i)
	{
	ASSERT(!m_finalized);
	uint8_t bytes[4];
	std::memcpy(bytes, &i, sizeof(i));

	// Though not always obvious, we don't have to invert the order of the
	// bytes written here for CPU(BIG_ENDIAN). This is because the incoming
	// i value is already ordered in big endian on CPU(BIG_EDNDIAN) platforms.
	write(bytes[0]);
	write(bytes[1]);
	write(bytes[2]);
	write(bytes[3]);
	}

	void rewind(MutableRef& ref)
	{
	ASSERT(ref.offset() < m_instructions.size());
	m_instructions.shrink(ref.offset());
	m_position = ref.offset();
	}

	std::unique_ptr<InstructionStream> finalize()
	{
	m_finalized = true;
	m_instructions.shrinkToFit();
	return std::unique_ptr<InstructionStream> { new InstructionStream(WTFMove(m_instructions)) };
	}

	MutableRef ref()
	{
	return MutableRef { m_instructions, m_position };
	}

	void swap(InstructionStreamWriter& other)
	{
	std::swap(m_finalized, other.m_finalized);
	std::swap(m_position, other.m_position);
	m_instructions.swap(other.m_instructions);
	}

	private:
	class iterator : public MutableRef {
	friend class InstructionStreamWriter;

	protected:
	using MutableRef::MutableRef;

	public:
	MutableRef& operator*()
	{
	return *this;
	}

	iterator& operator+=(size_t size)
	{
	m_index += size;
	return *this;
	}

	iterator& operator++()
	{
	return *this += ptr()->size();
	}
	};

	public:
	iterator begin()
	{
	return iterator { m_instructions, 0 };
	}

	iterator end()
	{
	return iterator { m_instructions, m_instructions.size() };
	}

	private:
	unsigned m_position { 0 };
	bool m_finalized { false };
	};


	} // namespace JSC