Source/JavaScriptCore/bytecode/ExecutableToCodeBlockEdge.h

/*
 * Copyright (C) 2018-2021 Apple Inc. All rights reserved.
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#pragma once

#include "ConcurrentJSLock.h"
#include "IsoSubspace.h"
#include "JSCast.h"
#include "VM.h"

namespace JSC {

class CodeBlock;
class LLIntOffsetsExtractor;

class ExecutableToCodeBlockEdge final : public JSCell {
public:
    typedef JSCell Base;
    static constexpr unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;

    template<typename CellType, SubspaceAccess>
    static IsoSubspace* subspaceFor(VM& vm)
    {
        return &vm.executableToCodeBlockEdgeSpace();
    }

    static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);

    static ExecutableToCodeBlockEdge* create(VM&, CodeBlock*);
    
    DECLARE_INFO;

    CodeBlock* codeBlock() const { return m_codeBlock.get(); }

    DECLARE_VISIT_CHILDREN;
    DECLARE_VISIT_OUTPUT_CONSTRAINTS;
    void finalizeUnconditionally(VM&);
    
    static CodeBlock* unwrap(ExecutableToCodeBlockEdge* edge)
    {
        if (!edge)
            return nullptr;
        return edge->codeBlock();
    }
    
    static CodeBlock* deactivateAndUnwrap(ExecutableToCodeBlockEdge* edge);
    
    static ExecutableToCodeBlockEdge* wrap(CodeBlock* codeBlock);
    
    static ExecutableToCodeBlockEdge* wrapAndActivate(CodeBlock* codeBlock);

    static ptrdiff_t offsetOfCodeBlock() { return OBJECT_OFFSETOF(ExecutableToCodeBlockEdge, m_codeBlock); }
    
private:
    friend class LLIntOffsetsExtractor;

    ExecutableToCodeBlockEdge(VM&, CodeBlock*);

    void finishCreation(VM&);

    void activate();
    void deactivate();
    bool isActive() const;

    template<typename Visitor> void runConstraint(const ConcurrentJSLocker&, VM&, Visitor&);

    WriteBarrier<CodeBlock> m_codeBlock;
};

} // namespace JSC