| /* |
| * Copyright (C) 2008 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 |
| |
| namespace JSC { |
| |
| struct ResultType { |
| private: |
| friend struct OperandTypes; |
| |
| using Type = uint8_t; |
| static const Type TypeInt32 = 1; |
| static const Type TypeMaybeNumber = 0x02; |
| static const Type TypeMaybeString = 0x04; |
| static const Type TypeMaybeNull = 0x08; |
| static const Type TypeMaybeBool = 0x10; |
| static const Type TypeMaybeBigInt = 0x20; |
| static const Type TypeMaybeOther = 0x40; |
| |
| static const Type TypeBits = TypeMaybeNumber | TypeMaybeString | TypeMaybeNull | TypeMaybeBool | TypeMaybeBigInt | TypeMaybeOther; |
| |
| public: |
| static const int numBitsNeeded = 7; |
| static_assert((TypeBits & ((1 << numBitsNeeded) - 1)) == TypeBits, "This is necessary for correctness."); |
| |
| explicit ResultType(Type type) |
| : m_bits(type) |
| { |
| } |
| |
| bool isInt32() const |
| { |
| return m_bits & TypeInt32; |
| } |
| |
| bool definitelyIsNumber() const |
| { |
| return (m_bits & TypeBits) == TypeMaybeNumber; |
| } |
| |
| bool definitelyIsString() const |
| { |
| return (m_bits & TypeBits) == TypeMaybeString; |
| } |
| |
| bool definitelyIsBoolean() const |
| { |
| return (m_bits & TypeBits) == TypeMaybeBool; |
| } |
| |
| bool definitelyIsBigInt() const |
| { |
| return (m_bits & TypeBits) == TypeMaybeBigInt; |
| } |
| |
| bool mightBeNumber() const |
| { |
| return m_bits & TypeMaybeNumber; |
| } |
| |
| bool isNotNumber() const |
| { |
| return !mightBeNumber(); |
| } |
| |
| bool mightBeBigInt() const |
| { |
| return m_bits & TypeMaybeBigInt; |
| } |
| |
| bool isNotBigInt() const |
| { |
| return !mightBeBigInt(); |
| } |
| |
| static ResultType nullType() |
| { |
| return ResultType(TypeMaybeNull); |
| } |
| |
| static ResultType booleanType() |
| { |
| return ResultType(TypeMaybeBool); |
| } |
| |
| static ResultType numberType() |
| { |
| return ResultType(TypeMaybeNumber); |
| } |
| |
| static ResultType numberTypeIsInt32() |
| { |
| return ResultType(TypeInt32 | TypeMaybeNumber); |
| } |
| |
| static ResultType stringOrNumberType() |
| { |
| return ResultType(TypeMaybeNumber | TypeMaybeString); |
| } |
| |
| static ResultType addResultType() |
| { |
| return ResultType(TypeMaybeNumber | TypeMaybeString | TypeMaybeBigInt); |
| } |
| |
| static ResultType stringType() |
| { |
| return ResultType(TypeMaybeString); |
| } |
| |
| static ResultType bigIntType() |
| { |
| return ResultType(TypeMaybeBigInt); |
| } |
| |
| static ResultType unknownType() |
| { |
| return ResultType(TypeBits); |
| } |
| |
| static ResultType forAdd(ResultType op1, ResultType op2) |
| { |
| if (op1.definitelyIsNumber() && op2.definitelyIsNumber()) |
| return numberType(); |
| if (op1.definitelyIsString() || op2.definitelyIsString()) |
| return stringType(); |
| if (op1.definitelyIsBigInt() && op2.definitelyIsBigInt()) |
| return bigIntType(); |
| return addResultType(); |
| } |
| |
| // Unlike in C, a logical op produces the value of the |
| // last expression evaluated (and not true or false). |
| static ResultType forLogicalOp(ResultType op1, ResultType op2) |
| { |
| if (op1.definitelyIsBoolean() && op2.definitelyIsBoolean()) |
| return booleanType(); |
| if (op1.definitelyIsNumber() && op2.definitelyIsNumber()) |
| return numberType(); |
| if (op1.definitelyIsString() && op2.definitelyIsString()) |
| return stringType(); |
| if (op1.definitelyIsBigInt() && op2.definitelyIsBigInt()) |
| return bigIntType(); |
| return unknownType(); |
| } |
| |
| static ResultType forBitOp() |
| { |
| return numberTypeIsInt32(); |
| } |
| |
| Type bits() const { return m_bits; } |
| |
| private: |
| Type m_bits; |
| }; |
| |
| struct OperandTypes |
| { |
| OperandTypes(ResultType first = ResultType::unknownType(), ResultType second = ResultType::unknownType()) |
| { |
| // We have to initialize one of the int to ensure that |
| // the entire struct is initialized. |
| m_u.i = 0; |
| m_u.rds.first = first.m_bits; |
| m_u.rds.second = second.m_bits; |
| } |
| |
| union { |
| struct { |
| ResultType::Type first; |
| ResultType::Type second; |
| } rds; |
| int i; |
| } m_u; |
| |
| ResultType first() |
| { |
| return ResultType(m_u.rds.first); |
| } |
| |
| ResultType second() |
| { |
| return ResultType(m_u.rds.second); |
| } |
| |
| int toInt() |
| { |
| return m_u.i; |
| } |
| static OperandTypes fromInt(int value) |
| { |
| OperandTypes types; |
| types.m_u.i = value; |
| return types; |
| } |
| }; |
| |
| } // namespace JSC |