Source/JavaScriptCore/wasm/WasmFunctionCodeBlockGenerator.h

/*
 * Copyright (C) 2019-2021 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

#if ENABLE(WEBASSEMBLY)

#include "BytecodeConventions.h"
#include "HandlerInfo.h"
#include "InstructionStream.h"
#include "MacroAssemblerCodeRef.h"
#include "WasmHandlerInfo.h"
#include "WasmLLIntTierUpCounter.h"
#include "WasmOps.h"
#include <wtf/HashMap.h>
#include <wtf/Vector.h>

namespace JSC {

class JITCode;
class LLIntOffsetsExtractor;

template<typename Traits>
class BytecodeGeneratorBase;

namespace Wasm {

class LLIntCallee;
class FunctionSignature;
struct GeneratorTraits;

struct JumpTableEntry {
    int target { 0 };
    unsigned startOffset;
    unsigned dropCount;
    unsigned keepCount;
};

using JumpTable = FixedVector<JumpTableEntry>;

class FunctionCodeBlockGenerator {
    WTF_MAKE_FAST_ALLOCATED;
    WTF_MAKE_NONCOPYABLE(FunctionCodeBlockGenerator);

    friend BytecodeGeneratorBase<GeneratorTraits>;
    friend LLIntOffsetsExtractor;
    friend class LLIntGenerator;
    friend class LLIntCallee;

public:
    FunctionCodeBlockGenerator(uint32_t functionIndex)
        : m_functionIndex(functionIndex)
    {
    }

    uint32_t functionIndex() const { return m_functionIndex; }
    unsigned numVars() const { return m_numVars; }
    unsigned numCalleeLocals() const { return m_numCalleeLocals; }
    uint32_t numArguments() const { return m_numArguments; }
    const Vector<Type>& constantTypes() const { return m_constantTypes; }
    const Vector<uint64_t>& constants() const { return m_constants; }
    const Vector<uint64_t>& constantRegisters() const { return m_constants; }
    const WasmInstructionStream& instructions() const { return *m_instructions; }

    void setNumVars(unsigned numVars) { m_numVars = numVars; }
    void setNumCalleeLocals(unsigned numCalleeLocals) { m_numCalleeLocals = numCalleeLocals; }

    ALWAYS_INLINE uint64_t getConstant(VirtualRegister reg) const { return m_constants[reg.toConstantIndex()]; }
    ALWAYS_INLINE Type getConstantType(VirtualRegister reg) const
    {
        ASSERT(Options::dumpGeneratedWasmBytecodes());
        return m_constantTypes[reg.toConstantIndex()];
    }

    void setInstructions(std::unique_ptr<WasmInstructionStream>);
    void addJumpTarget(WasmInstructionStream::Offset jumpTarget) { m_jumpTargets.append(jumpTarget); }
    WasmInstructionStream::Offset numberOfJumpTargets() { return m_jumpTargets.size(); }
    WasmInstructionStream::Offset lastJumpTarget() { return m_jumpTargets.last(); }

    void addOutOfLineJumpTarget(WasmInstructionStream::Offset, int target);
    WasmInstructionStream::Offset outOfLineJumpOffset(WasmInstructionStream::Offset);
    WasmInstructionStream::Offset outOfLineJumpOffset(const WasmInstructionStream::Ref& instruction)
    {
        return outOfLineJumpOffset(instruction.offset());
    }

    inline WasmInstructionStream::Offset bytecodeOffset(const WasmInstruction* returnAddress)
    {
        const auto* instructionsBegin = m_instructions->at(0).ptr();
        const auto* instructionsEnd = reinterpret_cast<const WasmInstruction*>(reinterpret_cast<uintptr_t>(instructionsBegin) + m_instructions->size());
        RELEASE_ASSERT(returnAddress >= instructionsBegin && returnAddress < instructionsEnd);
        return returnAddress - instructionsBegin;
    }

    HashMap<WasmInstructionStream::Offset, LLIntTierUpCounter::OSREntryData>& tierUpCounter() { return m_tierUpCounter; }

    unsigned addSignature(const FunctionSignature&);

    JumpTable& addJumpTable(size_t numberOfEntries);
    unsigned numberOfJumpTables() const;

    size_t numberOfExceptionHandlers() const { return m_exceptionHandlers.size(); }
    UnlinkedHandlerInfo& exceptionHandler(int index) { return m_exceptionHandlers[index]; }
    void addExceptionHandler(const UnlinkedHandlerInfo& handler) { m_exceptionHandlers.append(handler); }

private:
    using OutOfLineJumpTargets = HashMap<WasmInstructionStream::Offset, int>;

    uint32_t m_functionIndex;

    // Used for the number of WebAssembly locals, as in https://webassembly.github.io/spec/core/syntax/modules.html#syntax-local
    unsigned m_numVars { 0 };
    // Number of VirtualRegister. The naming is unfortunate, but has to match UnlinkedCodeBlock
    unsigned m_numCalleeLocals { 0 };
    uint32_t m_numArguments { 0 };
    Vector<Type> m_constantTypes;
    Vector<uint64_t> m_constants;
    std::unique_ptr<WasmInstructionStream> m_instructions;
    const void* m_instructionsRawPointer { nullptr };
    Vector<WasmInstructionStream::Offset> m_jumpTargets;
    Vector<const FunctionSignature*> m_signatures;
    OutOfLineJumpTargets m_outOfLineJumpTargets;
    HashMap<WasmInstructionStream::Offset, LLIntTierUpCounter::OSREntryData> m_tierUpCounter;
    Vector<JumpTable> m_jumpTables;
    Vector<UnlinkedHandlerInfo> m_exceptionHandlers;
};

} } // namespace JSC::Wasm

#endif // ENABLE(WEBASSEMBLY)