/*

* Copyright (C) 2013-2024 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.

*/

#pragma once

#include <JavaScriptCore/InstructionStream.h>

#include <JavaScriptCore/Opcode.h>

#include <limits.h>

#include <wtf/FastBitVector.h>

#include <wtf/TZoneMalloc.h>

#include <wtf/Vector.h>

namespace JSC {

class BytecodeGraph;

class CodeBlock;

class UnlinkedCodeBlock;

class UnlinkedCodeBlockGenerator;

template<typename> struct Instruction;

DECLARE_ALLOCATOR_WITH_HEAP_IDENTIFIER(BytecodeBasicBlock);

template<typename OpcodeTraits>

class BytecodeBasicBlock {

WTF_MAKE_TZONE_ALLOCATED_TEMPLATE(BytecodeBasicBlock);

WTF_MAKE_NONCOPYABLE(BytecodeBasicBlock);

friend class BytecodeGraph;

public:

using BasicBlockVector = Vector<BytecodeBasicBlock, 0, UnsafeVectorOverflow, 16, BytecodeBasicBlockMalloc>;

using InstructionType = BaseInstruction<OpcodeTraits>;

using InstructionStreamType = InstructionStream<InstructionType>;

static_assert(maxBytecodeStructLength <= UINT8_MAX);

enum SpecialBlockType { EntryBlock, ExitBlock };

inline BytecodeBasicBlock(const typename InstructionStreamType::Ref&, unsigned blockIndex);

inline BytecodeBasicBlock(SpecialBlockType, unsigned blockIndex);

BytecodeBasicBlock(BytecodeBasicBlock<OpcodeTraits>&&) = default;

bool isEntryBlock() { return !m_leaderOffset && !m_totalLength; }

bool isExitBlock() { return m_leaderOffset == UINT_MAX && m_totalLength == UINT_MAX; }

unsigned leaderOffset() const { return m_leaderOffset; }

unsigned totalLength() const { return m_totalLength; }

const Vector<uint8_t>& delta() const LIFETIME_BOUND { return m_delta; }

const Vector<unsigned>& successors() const LIFETIME_BOUND { return m_successors; }

FastBitVector& in() LIFETIME_BOUND { return m_in; }

FastBitVector& out() LIFETIME_BOUND { return m_out; }

unsigned index() const { return m_index; }

explicit operator bool() const { return true; }

private:

// Only called from BytecodeGraph.

static BasicBlockVector compute(CodeBlock*, const InstructionStreamType& instructions);

static BasicBlockVector compute(UnlinkedCodeBlockGenerator*, const InstructionStreamType& instructions);

template<typename Block> static BasicBlockVector computeImpl(Block* codeBlock, const InstructionStreamType& instructions);

void shrinkToFit();

void addSuccessor(BytecodeBasicBlock<OpcodeTraits>& block)

{

if (!m_successors.contains(block.index()))

m_successors.append(block.index());

}

inline void addLength(unsigned);

typename InstructionStreamType::Offset m_leaderOffset;

unsigned m_totalLength;

unsigned m_index;

Vector<uint8_t> m_delta;

Vector<unsigned> m_successors;

FastBitVector m_in;

FastBitVector m_out;

};

WTF_MAKE_TZONE_ALLOCATED_TEMPLATE_IMPL(template<typename OpcodeTraits>, BytecodeBasicBlock<OpcodeTraits>);

using JSBytecodeBasicBlock = BytecodeBasicBlock<JSOpcodeTraits>;

} // namespace JSC