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import WIT
protocol StaticCanonicalLowering: CanonicalLowering where Operand == StaticMetaOperand {
var printer: SourcePrinter { get }
var builder: SwiftFunctionBuilder { get }
var definitionMapping: DefinitionMapping { get }
}
extension StaticCanonicalLowering {
func lowerBool(_ value: Operand) -> Operand { .lowerBool(value) }
private func lowerIntToI32(_ value: Operand) -> Operand {
.call("Int32", arguments: [value])
}
private func lowerUIntToI32(_ value: Operand) -> Operand {
.call("Int32", arguments: [("bitPattern", .call("UInt32", arguments: [value]))])
}
func lowerUInt8(_ value: Operand) -> Operand { lowerUIntToI32(value) }
func lowerUInt16(_ value: Operand) -> Operand { lowerUIntToI32(value) }
func lowerUInt32(_ value: Operand) -> Operand { lowerUIntToI32(value) }
func lowerUInt64(_ value: Operand) -> Operand {
.call("Int64", arguments: [("bitPattern", value)])
}
func lowerInt8(_ value: Operand) -> Operand { lowerIntToI32(value) }
func lowerInt16(_ value: Operand) -> Operand { lowerIntToI32(value) }
func lowerInt32(_ value: Operand) -> Operand { lowerIntToI32(value) }
func lowerInt64(_ value: Operand) -> Operand { value }
func lowerFloat32(_ value: Operand) -> Operand { value }
func lowerFloat64(_ value: Operand) -> Operand { value }
func lowerChar(_ value: Operand) -> Operand {
lowerUInt32(.accessField(value, name: "value"))
}
func lowerEnum(_ value: Operand, type: WITEnum) throws -> Operand {
lowerUIntToI32(.accessField(value, name: "witRawValue"))
}
func lowerFlags(_ value: Operand, type: WITFlags) throws -> [Operand] {
let rawValueTypes = CanonicalABI.rawType(ofFlags: type.flags.count)
let rawValue = Operand.accessField(value, name: "rawValue")
if rawValueTypes.bitsSlots.count == 1 {
return [lowerUIntToI32(rawValue)]
}
return rawValueTypes.swiftTypeNames.indices.map {
lowerUIntToI32(.accessField(rawValue, name: "field\($0)"))
}
}
func lowerOption(
_ value: Operand, wrapped: WITType,
lowerPayload: (Operand) throws -> [Operand]
) throws -> (discriminant: Operand, payload: [Operand]) {
return try lowerVariantLike(
value, variants: [nil, wrapped],
swiftCaseNames: ["none", "some"],
lowerPayload: { caseIndex, payload in
// If `some`
if caseIndex == 1 {
return try lowerPayload(payload)
}
// If `none`
let coreTypes = CanonicalABI.flatten(type: wrapped).map(\.type)
return coreTypes.map { self.makeZeroValue(of: $0) }
}
)
}
func lowerResult(
_ value: Operand, ok: WITType?, error: WITType?,
lowerPayload: (Bool, Operand) throws -> [Operand]
) throws -> (discriminant: Operand, payload: [Operand]) {
return try lowerVariantLike(
value, variants: [ok, error],
swiftCaseNames: ["success", "failure"],
lowerPayload: { caseIndex, payload in
let isFailure = caseIndex == 1
let payload = isFailure ? .accessField(payload, name: "content") : payload
return try lowerPayload(isFailure, payload)
}
)
}
private func lowerRecordLike(_ value: Operand, fieldNames: [String], temporaryVariablePrefix: String) -> [Operand] {
var lowered: [Operand] = []
for fieldName in fieldNames {
let fieldVar = builder.variable(temporaryVariablePrefix + ConvertCase.pascalCase(kebab: fieldName))
printer.write(line: "let \(fieldVar) = \(value).\(fieldName)")
lowered.append(.variable(fieldVar))
}
return lowered
}
func lowerRecord(_ value: Operand, type: WITRecord) -> [Operand] {
return lowerRecordLike(
value, fieldNames: type.fields.map { ConvertCase.camelCase(kebab: $0.name) },
temporaryVariablePrefix: "record"
)
}
func lowerTuple(_ value: Operand, types: [WIT.WITType]) -> [Operand] {
return lowerRecordLike(
value, fieldNames: types.indices.map { $0.description },
temporaryVariablePrefix: "tuple"
)
}
func lowerVariant(
_ value: Operand, type: WITVariant, lowerPayload: (Int, Operand) throws -> [Operand]
) throws -> (discriminant: Operand, payload: [Operand]) {
return try lowerVariantLike(
value, variants: type.cases.map(\.type),
swiftCaseNames: definitionMapping.enumCaseSwiftNames(variantType: type),
lowerPayload: lowerPayload
)
}
func lowerVariantLike(
_ value: Operand, variants: [WITType?], swiftCaseNames: [String],
lowerPayload: (Int, Operand) throws -> [Operand]
) throws -> (discriminant: Operand, payload: [Operand]) {
let discriminantType = CanonicalABI.discriminantType(numberOfCases: UInt32(variants.count))
let discriminantVar = builder.variable("discriminant")
let payloadVar = builder.variable("payload")
// Declare lowered variables
printer.write(line: "let \(discriminantVar): \(discriminantType.asCoreType.swiftTypeName)")
let payloadCoreTypes = CanonicalABI.flattenVariantPayload(variants: variants)
let payloadCoreVars = payloadCoreTypes.map { _ in builder.variable("loweredPayloed") }
for (type, varName) in zip(payloadCoreTypes, payloadCoreVars) {
printer.write(line: "let \(varName): \(type.swiftTypeName)")
}
// Start switch
printer.write(line: "switch \(value) {")
for (caseIndex, payloadType) in variants.enumerated() {
// Handle a case
let caseName = swiftCaseNames[caseIndex]
var casePattern = "case .\(SwiftName.makeName(caseName))"
if payloadType != nil {
casePattern += "(let \(payloadVar))"
}
casePattern += ":"
printer.write(line: casePattern)
try printer.indent {
// Lower discriminant
printer.write(line: "\(discriminantVar) = \(caseIndex)")
// Lower payload even though the case doesn't have payload,
// initialize the payload with zeros
let loweredSinglePayload = try lowerPayload(caseIndex, .variable(payloadVar))
for (destCoreVar, srcCoreValue) in zip(payloadCoreVars, loweredSinglePayload) {
printer.write(line: "\(destCoreVar) = \(srcCoreValue)")
}
}
}
printer.write(line: "}")
// End switch
return (.variable(discriminantVar), payloadCoreVars.map { .variable($0) })
}
func makeZeroValue(of type: CanonicalABI.CoreType) -> Operand {
switch type {
case .i32: return .literal("Int32(0)")
case .i64: return .literal("Int64(0)")
case .f32: return .literal("Float32(0)")
case .f64: return .literal("Float64(0)")
}
}
func numericCast(_ value: Operand, from source: CanonicalABI.CoreType, to destination: CanonicalABI.CoreType) -> Operand {
switch (source, destination) {
case (.i32, .i32), (.i64, .i64), (.f32, .f32), (.f64, .f64): return value
case (.i32, .f32):
return .call("Float32", arguments: [("bitPattern", value)])
case (.i32, .f64):
return .call("Float32", arguments: [("bitPattern", numericCast(value, from: .i32, to: .i64))])
case (.i32, .i64):
return .call("Int64", arguments: [value])
case (.f32, .i64):
return numericCast(numericCast(value, from: .f32, to: .i32), from: .i32, to: .f64)
case (.f32, .f64):
return .call("Float64", arguments: [value])
case (.i64, .f64):
return .call("Float64", arguments: [("bitPattern", value)])
case (.f64, .i64), (.f32, .i32):
return .accessField(value, name: "bitPattern")
case (.i64, .i32), (.i64, .f32), (.f64, .i32), (.f64, .f32):
fatalError("Should not trucate while casting")
}
}
}
extension CanonicalABI.CoreType {
fileprivate var swiftTypeName: String {
switch self {
case .i32: return "Int32"
case .i64: return "Int64"
case .f32: return "Float32"
case .f64: return "Float64"
}
}
}
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