emitter.vb

大名鼎鼎的mono是.NET平台的跨平台（支持linux

    End Sub

    Shared Sub EmitConv_U8_Overflow(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_Ovf_U8)
        Info.Stack.Push(Info.Compiler.TypeCache.System_UInt64)
    End Sub

    Shared Sub EmitConv_U8_Overflow_Underflow(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_Ovf_U8_Un)
        Info.Stack.Push(Info.Compiler.TypeCache.System_UInt64)
    End Sub

    Shared Sub EmitConv_I8(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_I8)
        Info.Stack.Push(Info.Compiler.TypeCache.System_Int64)
    End Sub

    Shared Sub EmitConv_I8_Overflow(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_Ovf_I8)
        Info.Stack.Push(Info.Compiler.TypeCache.System_Int64)
    End Sub

    Shared Sub EmitConv_I8_Overflow_Underflow(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_Ovf_I8_Un)
        Info.Stack.Push(Info.Compiler.TypeCache.System_Int64)
    End Sub

    Shared Sub EmitConv_R8(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_R8)
        Info.Stack.Push(Info.Compiler.TypeCache.System_Double)
    End Sub

    Shared Sub EmitConv_R4(ByVal Info As EmitInfo, ByVal FromType As Type)
        FromType = Helper.GetTypeOrTypeBuilder(FromType)
        Info.Stack.Pop(FromType)
        Info.ILGen.Emit(OpCodes.Conv_R4)
        Info.Stack.Push(Info.Compiler.TypeCache.System_Single)
    End Sub

    ''' <summary>
    ''' Convert the value on the stack to ToType.
    ''' </summary>
    ''' <param name="ToType"></param>
    ''' <remarks></remarks>
    Shared Sub EmitConversion(ByVal FromType As Type, ByVal ToType As Type, ByVal Info As EmitInfo)
        Dim ToTypeOriginal, FromTypeOriginal As Type

        If Helper.CompareType(FromType, Info.Compiler.TypeCache.Nothing) Then Return

        ToTypeOriginal = ToType
        ToType = Helper.GetTypeOrTypeBuilder(ToType)

        'Dim FromType As Type = Info.Stack.Peek
        Dim FromTP, ToTP As TypeCode
        Dim converted As Boolean = False

        FromTypeOriginal = FromType
        FromType = Helper.GetTypeOrTypeBuilder(FromType)

        FromTP = Helper.GetTypeCode(Info.Compiler, FromType)
        ToTP = Helper.GetTypeCode(info.Compiler, ToType)

#If DEBUGIMPLICITCONVERSION Then
                    		If FromTP <> ToTP OrElse FromTP = TypeCode.Object OrElse ToTP = TypeCode.Object Then
                    			Compiler.Report.WriteLine(vbnc.Report.ReportLevels.Debug, String.Format("Converting from '{0}' to '{1}'.", FromTP.ToString, ToTP.ToString))
                    		End If
#End If

        If ToTP = TypeCode.Object AndAlso FromTP <> TypeCode.Object AndAlso Helper.CompareType(ToType, Info.Compiler.TypeCache.System_Object) = False Then
            EmitValueTypeToObjectConversion(Info, FromType, ToType)
            Return
        End If

        Dim Switch As TypeCombinations = Helper.GetCombination(FromTP, ToTP)

        Select Case Switch
            Case TypeCombinations.Boolean_Boolean, _
             TypeCombinations.Byte_Byte, _
              TypeCombinations.Char_Char, _
               TypeCombinations.DateTime_DateTime, _
                TypeCombinations.Decimal_Decimal, _
                 TypeCombinations.Double_Double, _
                  TypeCombinations.Empty_Empty, _
                   TypeCombinations.Int16_Int16, _
                    TypeCombinations.Int32_Int32, _
                     TypeCombinations.Int64_Int64, _
                       TypeCombinations.SByte_SByte, _
                        TypeCombinations.Single_Single, _
                         TypeCombinations.String_String, _
                          TypeCombinations.UInt16_UInt16, _
                           TypeCombinations.UInt32_UInt32, _
                            TypeCombinations.UInt64_UInt64
                Return 'Nothing to convert, both types are equal
            Case TypeCombinations.Object_Object
                Dim tmpTo, tmpFrom As Type
                If Info.IsExplicitConversion = False Then
                    'If TypeOf FromType Is TypeDescriptor Then
                    '    tmpFrom = DirectCast(FromType, TypeDescriptor).TypeInReflection
                    'Else
                    '    tmpFrom = FromType
                    'End If
                    tmpFrom = FromTypeOriginal
                    'If TypeOf ToTypeIn Is TypeDescriptor Then
                    '    tmpTo = DirectCast(ToType, TypeDescriptor).TypeInReflection
                    'Else
                    tmpTo = ToTypeOriginal
                    '               End If
                    If Helper.CompareType(tmpTo, tmpFrom) Then
                        converted = True
                    ElseIf Helper.IsAssignable(Info.Compiler, tmpFrom, tmpTo) Then
                        converted = True
                    Else
                        converted = True
                        Info.Compiler.Report.WriteLine(Report.ReportLevels.Debug, "The compiler supposes a conversion from " & tmpFrom.Name & " to " & tmpTo.Name & " is valid.")
                    End If
                Else
                    Info.ILGen.Emit(OpCodes.Castclass, ToType)
                    'Emitter.EmitCastClass(Info, FromType, ToType)
                    converted = True
                End If
                ' ToSByte conversions
            Case TypeCombinations.Byte_SByte
                If Info.IsExplicitConversion Then
                    If Info.IntegerOverflowChecks Then
                        Info.ILGen.Emit(OpCodes.Conv_Ovf_I1_Un) : converted = True
                    Else
                        Info.ILGen.Emit(OpCodes.Conv_I1)
                    End If
                Else
                    Helper.Stop()
                End If
            Case TypeCombinations.Int16_SByte
            Case TypeCombinations.UInt16_SByte
            Case TypeCombinations.Int32_SByte
                If Info.IsExplicitConversion Then
                    If Info.IntegerOverflowChecks Then
                        Info.ILGen.Emit(OpCodes.Conv_Ovf_I1) : converted = True
                    Else
                        Info.ILGen.Emit(OpCodes.Conv_I1) : converted = True
                    End If
                Else
                    Helper.Stop()
                End If
            Case TypeCombinations.UInt32_SByte
            Case TypeCombinations.Int64_SByte
            Case TypeCombinations.UInt64_SByte
            Case TypeCombinations.Single_SByte
            Case TypeCombinations.Double_SByte
            Case TypeCombinations.Decimal_SByte

                'ToByte conversions
            Case TypeCombinations.SByte_Byte, _
              TypeCombinations.Int16_Byte, _
              TypeCombinations.Int32_Byte, _
              TypeCombinations.Int64_Byte
                If Info.IsExplicitConversion Then
                    If Info.IntegerOverflowChecks Then
                        Info.ILGen.Emit(OpCodes.Conv_Ovf_U1) : converted = True
                    Else
                        Info.ILGen.Emit(OpCodes.Conv_U1) : converted = True
                    End If
                Else
                    Helper.Stop()
                End If
            Case TypeCombinations.UInt16_Byte
            Case TypeCombinations.UInt32_Byte
            Case TypeCombinations.UInt64_Byte
            Case TypeCombinations.Single_Byte
            Case TypeCombinations.Double_Byte
            Case TypeCombinations.Decimal_Byte

                'ToUInt64 conversions
            Case TypeCombinations.Byte_UInt16
                Info.ILGen.Emit(OpCodes.Conv_U2)
                converted = True

                'ToInt16 conversions
            Case TypeCombinations.Byte_Int16, _
             TypeCombinations.SByte_Int16
                Info.ILGen.Emit(OpCodes.Conv_I2)
                converted = True


                'ToUInt32 conversions
            Case TypeCombinations.Byte_UInt32, _
               TypeCombinations.UInt16_UInt32
                Info.ILGen.Emit(OpCodes.Conv_U4)
                converted = True

                'ToInt32 conversions
            Case TypeCombinations.SByte_Int32, _
                 TypeCombinations.Byte_Int32, _
                 TypeCombinations.UInt16_Int32, _
                 TypeCombinations.Int16_Int32
                Info.ILGen.Emit(OpCodes.Conv_I4)
                converted = True
            Case TypeCombinations.Object_Int32
                'Narrowing conversion
                If Info.IsExplicitConversion = False Then
                    Helper.AddError()
                Else
                    Emitter.EmitUnbox(Info, Info.Compiler.TypeCache.System_Int32)
                    Emitter.EmitLdobj(Info, Info.Compiler.TypeCache.System_Int32)
                    converted = True
                End If

                'ToInt64 conversions
            Case TypeCombinations.Byte_Int64, _
              TypeCombinations.SByte_Int64, _
               TypeCombinations.UInt16_Int64, _
                TypeCombinations.Int16_Int64, _
                 TypeCombinations.UInt32_Int64, _
                  TypeCombinations.Int32_Int64
                Info.ILGen.Emit(OpCodes.Conv_I8)
                converted = True

                'ToUInt64 conversions
            Case TypeCombinations.Byte_UInt64, _
                  TypeCombinations.UInt16_UInt64, _
                   TypeCombinations.UInt32_UInt64
                Info.ILGen.Emit(OpCodes.Conv_U8)
                converted = True

                'ToSingle conversions
            Case TypeCombinations.SByte_Single, _
                  TypeCombinations.Byte_Single, _
                   TypeCombinations.UInt16_Single, _
                    TypeCombinations.Int16_Single, _
                     TypeCombinations.UInt32_Single, _
                      TypeCombinations.Int32_Single, _
                       TypeCombinations.UInt64_Single, _
                        TypeCombinations.Int64_Single
                Info.ILGen.Emit(OpCodes.Conv_R4)
                converted = True
            Case TypeCombinations.Decimal_Single
                Info.ILGen.Emit(OpCodes.Call, Info.Compiler.TypeCache.System_Convert__ToSingle_Decimal)
                converted = True

                'ToDouble conversions
            Case TypeCombinations.Decimal_Double
                Info.ILGen.Emit(OpCodes.Call, Info.Compiler.TypeCache.System_Convert__ToDouble_Decimal)
                converted = True
            Case TypeCombinations.SByte_Double, _
                  TypeCombinations.Byte_Double, _
                   TypeCombinations.UInt16_Double, _
                    TypeCombinations.Int16_Double, _
                     TypeCombinations.UInt32_Double, _
                      TypeCombinations.Int32_Double, _
                       TypeCombinations.UInt64_Double, _
                        TypeCombinations.Int64_Double, _
                         TypeCombinations.Single_Double
                Info.ILGen.Emit(OpCodes.Conv_R8)
                converted = True

                'ToDecimal conversions
            Case TypeCombinations.Byte_Decimal, _
             TypeCombinations.SByte_Decimal, _
             TypeCombinations.Int16_Decimal
                Info.ILGen.Emit(OpCodes.Conv_I4)
                Info.ILGen.Emit(OpCodes.Newobj, Info.Compiler.TypeCache.System_Decimal__ctor_Int32)
                converted = True
            Case TypeCombinations.UInt16_Decimal, _
               TypeCombinations.UInt32_Decimal
                Info.ILGen.Emit(OpCodes.Conv_I8)
                Info.ILGen.Emit(OpCodes.Newobj, Info.Compiler.TypeCache.System_Decimal__ctor_Int64)
                converted = True
            Case TypeCombinations.Int32_Decimal
                Info.ILGen.Emit(OpCodes.Newobj, Info.Compiler.TypeCache.System_Decimal__ctor_Int32)
                converted = True
            Case TypeCombinations.UInt64_Decimal
                Info.ILGen.Emit(OpCodes.Newobj, Info.Compiler.TypeCache.System_Decimal__ctor_UInt64)
                converted = True
            Case TypeCombinations.Int64_Decimal
                Info.ILGen.Emit(OpCodes.Newobj, Info.Compiler.TypeCache.System_Decimal__ctor_Int64)
                converted = True

                'ToObject conversions
            Case TypeCombinations.SByte_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_SByte)
                converted = True
            Case TypeCombinations.Byte_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Byte)
                converted = True
            Case TypeCombinations.Int16_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Int16)
                converted = True
            Case TypeCombinations.UInt16_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_UInt16)
                converted = True
            Case TypeCombinations.Int32_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Int32)
                converted = True
            Case TypeCombinations.UInt32_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_UInt32)
                converted = True
            Case TypeCombinations.Int64_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Int64)
                converted = True
            Case TypeCombinations.UInt64_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_UInt64)
                converted = True
            Case TypeCombinations.Single_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Single)
                converted = True
            Case TypeCombinations.Double_Object
                Info.ILGen.Emit(OpCodes.Box, Info.Compiler.TypeCache.System_Double)
                converted = True
            Case TypeCombinations.String_Object
                converted = True
            Case TypeCombinations.Decimal_Object