C++ StackTypeSet类代码示例

bool
TypeInferenceOracle::elementReadIsTypedArray(RawScript script, jsbytecode *pc, int *arrayType)
{
    // Check whether the object is a typed array and index is int32 or double.
    StackTypeSet *obj = script->analysis()->poppedTypes(pc, 1);
    StackTypeSet *id = script->analysis()->poppedTypes(pc, 0);

    JSValueType idType = id->getKnownTypeTag();
    if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
        return false;

    if (obj->hasType(types::Type::StringType()))
        return false;

    *arrayType = obj->getTypedArrayType();
    if (*arrayType == TypedArray::TYPE_MAX)
        return false;

    JS_ASSERT(*arrayType >= 0 && *arrayType < TypedArray::TYPE_MAX);

    // Unlike dense arrays, the types of elements in typed arrays are not
    // guaranteed to be present in the object's type, and we need to use
    // knowledge about the possible contents of the array vs. the types
    // that have been read out of it to figure out how to do the load.
    types::TypeSet *result = propertyRead(script, pc);
    if (*arrayType == TypedArray::TYPE_FLOAT32 || *arrayType == TypedArray::TYPE_FLOAT64) {
        if (!result->hasType(types::Type::DoubleType()))
            return false;
    } else {
        if (!result->hasType(types::Type::Int32Type()))
            return false;
    }

    return true;
}

bool
TypeInferenceOracle::elementReadShouldAlwaysLoadDoubles(RawScript script, jsbytecode *pc)
{
    StackTypeSet *types = script->analysis()->poppedTypes(pc, 1);
    types::StackTypeSet::DoubleConversion conversion = types->convertDoubleElements(cx);
    return conversion == StackTypeSet::AlwaysConvertToDoubles;
}

MIRType
TypeInferenceOracle::elementWrite(UnrootedScript script, jsbytecode *pc)
{
    StackTypeSet *objTypes = script->analysis()->poppedTypes(pc, 2);
    MIRType elementType = MIRType_None;
    unsigned count = objTypes->getObjectCount();

    for (unsigned i = 0; i < count; i++) {
        if (objTypes->getSingleObject(i))
            return MIRType_None;

        if (TypeObject *object = objTypes->getTypeObject(i)) {
            types::HeapTypeSet *elementTypes = object->getProperty(cx, JSID_VOID, false);
            if (!elementTypes)
                return MIRType_None;

            MIRType type = getMIRType(elementTypes);
            if (type == MIRType_None)
                return MIRType_None;

            if (elementType == MIRType_None)
                elementType = type;
            else if (elementType != type)
                return MIRType_None;
        }
    }

    return elementType;
}

bool
TypeInferenceOracle::propertyReadIdempotent(HandleScript script, jsbytecode *pc, HandleId id)
{
    if (script->analysis()->getCode(pc).notIdempotent)
        return false;

    if (id != MakeTypeId(cx, id))
        return false;

    StackTypeSet *types = script->analysis()->poppedTypes(pc, 0);
    if (!types || types->unknownObject())
        return false;

    for (unsigned i = 0; i < types->getObjectCount(); i++) {
        if (types->getSingleObject(i))
            return false;

        if (TypeObject *obj = types->getTypeObject(i)) {
            if (obj->unknownProperties())
                return false;

            // Check if the property has been reconfigured or is a getter.
            HeapTypeSet *propertyTypes = obj->getProperty(cx, id, false);
            if (!propertyTypes || propertyTypes->isOwnProperty(cx, obj, true))
                return false;
        }
    }

    return true;
}

bool
TypeInferenceOracle::elementWriteHasExtraIndexedProperty(RawScript script, jsbytecode *pc)
{
    StackTypeSet *obj = script->analysis()->poppedTypes(pc, 2);

    if (obj->hasObjectFlags(cx, types::OBJECT_FLAG_LENGTH_OVERFLOW))
        return true;

    return types::TypeCanHaveExtraIndexedProperties(cx, obj);
}

bool
TypeInferenceOracle::elementReadIsDenseNative(RawScript script, jsbytecode *pc)
{
    // Check whether the object is a dense array and index is int32 or double.
    StackTypeSet *obj = script->analysis()->poppedTypes(pc, 1);
    StackTypeSet *id = script->analysis()->poppedTypes(pc, 0);

    JSValueType idType = id->getKnownTypeTag();
    if (idType != JSVAL_TYPE_INT32 && idType != JSVAL_TYPE_DOUBLE)
        return false;

    Class *clasp = obj->getKnownClass();
    return clasp && clasp->isNative();
}

bool
TypeInferenceOracle::elementReadIsString(JSScript *script, jsbytecode *pc)
{
    // Check for string[int32].
    StackTypeSet *value = script->analysis()->poppedTypes(pc, 1);
    StackTypeSet *id = script->analysis()->poppedTypes(pc, 0);

    if (value->getKnownTypeTag() != JSVAL_TYPE_STRING)
        return false;

    if (id->getKnownTypeTag() != JSVAL_TYPE_INT32)
        return false;

    types::TypeSet *pushed = script->analysis()->pushedTypes(pc, 0);
    if (!pushed->hasType(types::Type::StringType()))
        return false;

    return true;
}