PredictedType.h   [plain text]

/*
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 *     from this software without specific prior written permission.
 *
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#ifndef PredictedType_h
#define PredictedType_h

#include "JSValue.h"

namespace JSC {

class Structure;

typedef uint32_t PredictedType;
static const PredictedType PredictNone          = 0x00000000; // We don't know anything yet.
static const PredictedType PredictFinalObject   = 0x00000001; // It's definitely a JSFinalObject.
static const PredictedType PredictArray         = 0x00000002; // It's definitely a JSArray.
static const PredictedType PredictByteArray     = 0x00000004; // It's definitely a JSByteArray or one of its subclasses.
static const PredictedType PredictFunction      = 0x00000008; // It's definitely a JSFunction or one of its subclasses.
static const PredictedType PredictInt8Array     = 0x00000010; // It's definitely an Int8Array or one of its subclasses.
static const PredictedType PredictInt16Array    = 0x00000020; // It's definitely an Int16Array or one of its subclasses.
static const PredictedType PredictInt32Array    = 0x00000040; // It's definitely an Int32Array or one of its subclasses.
static const PredictedType PredictUint8Array    = 0x00000080; // It's definitely an Uint8Array or one of its subclasses.
static const PredictedType PredictUint16Array   = 0x00000100; // It's definitely an Uint16Array or one of its subclasses.
static const PredictedType PredictUint32Array   = 0x00000200; // It's definitely an Uint32Array or one of its subclasses.
static const PredictedType PredictFloat32Array  = 0x00000400; // It's definitely an Uint16Array or one of its subclasses.
static const PredictedType PredictFloat64Array  = 0x00000800; // It's definitely an Uint16Array or one of its subclasses.
static const PredictedType PredictObjectOther   = 0x00001000; // It's definitely an object but not JSFinalObject, JSArray, JSByteArray, or JSFunction.
static const PredictedType PredictObjectMask    = 0x00001fff; // Bitmask used for testing for any kind of object prediction.
static const PredictedType PredictString        = 0x00002000; // It's definitely a JSString.
static const PredictedType PredictCellOther     = 0x00004000; // It's definitely a JSCell but not a subclass of JSObject and definitely not a JSString.
static const PredictedType PredictCell          = 0x00007fff; // It's definitely a JSCell.
static const PredictedType PredictInt32         = 0x00008000; // It's definitely an Int32.
static const PredictedType PredictDouble        = 0x00010000; // It's definitely a Double.
static const PredictedType PredictNumber        = 0x00018000; // It's either an Int32 or a Double.
static const PredictedType PredictBoolean       = 0x00020000; // It's definitely a Boolean.
static const PredictedType PredictOther         = 0x40000000; // It's definitely none of the above.
static const PredictedType PredictTop           = 0x7fffffff; // It can be any of the above.
static const PredictedType FixedIndexedStorageMask = PredictByteArray | PredictInt8Array | PredictInt16Array | PredictInt32Array | PredictUint8Array | PredictUint16Array | PredictUint32Array | PredictFloat32Array | PredictFloat64Array;

typedef bool (*PredictionChecker)(PredictedType);

inline bool isCellPrediction(PredictedType value)
{
    return !!(value & PredictCell) && !(value & ~PredictCell);
}

inline bool isObjectPrediction(PredictedType value)
{
    return !!(value & PredictObjectMask) && !(value & ~PredictObjectMask);
}

inline bool isFinalObjectPrediction(PredictedType value)
{
    return value == PredictFinalObject;
}

inline bool isFinalObjectOrOtherPrediction(PredictedType value)
{
    return !!(value & (PredictFinalObject | PredictOther)) && !(value & ~(PredictFinalObject | PredictOther));
}

inline bool isFixedIndexedStorageObjectPrediction(PredictedType value)
{
    return (value & FixedIndexedStorageMask) == value;
}

inline bool isStringPrediction(PredictedType value)
{
    return value == PredictString;
}

inline bool isArrayPrediction(PredictedType value)
{
    return value == PredictArray;
}

inline bool isFunctionPrediction(PredictedType value)
{
    return value == PredictFunction;
}

inline bool isByteArrayPrediction(PredictedType value)
{
    return value == PredictByteArray;
}

inline bool isInt8ArrayPrediction(PredictedType value)
{
    return value == PredictInt8Array;
}

inline bool isInt16ArrayPrediction(PredictedType value)
{
    return value == PredictInt16Array;
}

inline bool isInt32ArrayPrediction(PredictedType value)
{
    return value == PredictInt32Array;
}

inline bool isUint8ArrayPrediction(PredictedType value)
{
    return value == PredictUint8Array;
}

inline bool isUint16ArrayPrediction(PredictedType value)
{
    return value == PredictUint16Array;
}

inline bool isUint32ArrayPrediction(PredictedType value)
{
    return value == PredictUint32Array;
}

inline bool isFloat32ArrayPrediction(PredictedType value)
{
    return value == PredictFloat32Array;
}

inline bool isFloat64ArrayPrediction(PredictedType value)
{
    return value == PredictFloat64Array;
}

inline bool isArrayOrOtherPrediction(PredictedType value)
{
    return !!(value & (PredictArray | PredictOther)) && !(value & ~(PredictArray | PredictOther));
}

inline bool isInt32Prediction(PredictedType value)
{
    return value == PredictInt32;
}

inline bool isDoublePrediction(PredictedType value)
{
    return value == PredictDouble;
}

inline bool isNumberPrediction(PredictedType value)
{
    return !!(value & PredictNumber) && !(value & ~PredictNumber);
}

inline bool isBooleanPrediction(PredictedType value)
{
    return value == PredictBoolean;
}

inline bool isOtherPrediction(PredictedType value)
{
    return value == PredictOther;
}

#ifndef NDEBUG
const char* predictionToString(PredictedType value);
#endif

// Merge two predictions. Note that currently this just does left | right. It may
// seem tempting to do so directly, but you would be doing so at your own peril,
// since the merging protocol PredictedType may change at any time (and has already
// changed several times in its history).
inline PredictedType mergePredictions(PredictedType left, PredictedType right)
{
    return left | right;
}

template<typename T>
inline bool mergePrediction(T& left, PredictedType right)
{
    PredictedType newPrediction = static_cast<T>(mergePredictions(static_cast<PredictedType>(left), right));
    bool result = newPrediction != static_cast<PredictedType>(left);
    left = newPrediction;
    return result;
}

PredictedType predictionFromClassInfo(const ClassInfo*);
PredictedType predictionFromStructure(Structure*);
PredictedType predictionFromCell(JSCell*);
PredictedType predictionFromValue(JSValue);

} // namespace JSC

#endif // PredictedType_h