qqmljsbasicblocks_p.h

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// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
 
#ifndef QQMLJSBASICBLOCKS_P_H
#define QQMLJSBASICBLOCKS_P_H
 
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
 
 
#include <private/qqmljscompilepass_p.h>
#include <private/qflatmap_p.h>
 
QT_BEGIN_NAMESPACE
 
class Q_QMLCOMPILER_PRIVATE_EXPORT QQmlJSBasicBlocks : public QQmlJSCompilePass
{
public:
    struct BasicBlock {
        QList<int> jumpOrigins;
        QList<int> readRegisters;
        QList<QQmlJSScope::ConstPtr> readTypes;
        int jumpTarget = -1;
        bool jumpIsUnconditional = false;
    };
 
    QQmlJSBasicBlocks(const QV4::Compiler::Context *context,
                      const QV4::Compiler::JSUnitGenerator *unitGenerator,
                      const QQmlJSTypeResolver *typeResolver, QQmlJSLogger *logger)
        : QQmlJSCompilePass(unitGenerator, typeResolver, logger), m_context{ context }
    {
    }
 
    ~QQmlJSBasicBlocks() = default;
 
    InstructionAnnotations run(
            const Function *function, const InstructionAnnotations &annotations,
            QQmlJS::DiagnosticMessage *error);
 
private:
    struct RegisterAccess
    {
        QList<QQmlJSScope::ConstPtr> trackedTypes;
        QHash<int, QQmlJSScope::ConstPtr> typeReaders;
        QHash<int, QList<int>> registerReadersAndConversions;
        int trackedRegister;
    };
 
    struct ObjectOrArrayDefinition
    {
        static constexpr int arrayClassId = -1;
 
        int instructionOffset = -1;
        int internalClassId = -1;
        int argc = 0;
        int argv = -1;
    };
 
    QV4::Moth::ByteCodeHandler::Verdict startInstruction(QV4::Moth::Instr::Type type) override;
    void endInstruction(QV4::Moth::Instr::Type type) override;
 
    void generate_Jump(int offset) override;
    void generate_JumpTrue(int offset) override;
    void generate_JumpFalse(int offset) override;
    void generate_JumpNoException(int offset) override;
    void generate_JumpNotUndefined(int offset) override;
 
    void generate_Ret() override;
    void generate_ThrowException() override;
 
    void generate_DefineArray(int argc, int argv) override;
    void generate_DefineObjectLiteral(int internalClassId, int argc, int args) override;
 
    enum JumpMode { Unconditional, Conditional };
    void processJump(int offset, JumpMode mode);
    void populateBasicBlocks();
    void populateReaderLocations();
    void adjustTypes();
    bool canMove(int instructionOffset, const RegisterAccess &access) const;
 
    void dumpBasicBlocks();
    void dumpDOTGraph();
 
    const QV4::Compiler::Context *m_context;
    InstructionAnnotations m_annotations;
    QFlatMap<int, BasicBlock> m_basicBlocks;
    QHash<int, RegisterAccess> m_readerLocations;
    QList<ObjectOrArrayDefinition> m_objectAndArrayDefinitions;
    bool m_skipUntilNextLabel = false;
    bool m_hadBackJumps = false;
};
 
QT_END_NAMESPACE
 
#endif // QQMLJSBASICBLOCKS_P_H