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import WIT
struct GuestStaticCanonicalLifting: StaticCanonicalLifting {
typealias Operand = StaticMetaOperand
typealias Pointer = StaticMetaPointer
var printer: SourcePrinter
var builder: SwiftFunctionBuilder
let definitionMapping: DefinitionMapping
func liftUInt(_ value: Operand, bitWidth: Int) -> Operand {
let sourceBiWidth = bitWidth == 64 ? 64 : 32
return .call(
"UInt\(bitWidth)",
arguments: [
.call("UInt\(sourceBiWidth)", arguments: [("bitPattern", value)])
])
}
func liftInt(_ value: Operand, bitWidth: Int) -> Operand {
.call("Int\(bitWidth)", arguments: [value])
}
func liftPointer(_ value: Operand, pointeeTypeName: String) -> Operand {
.forceUnwrap(
.call(
"UnsafePointer<\(pointeeTypeName)>",
arguments: [
(
"bitPattern", .call("Int", arguments: [value])
)
]
))
}
func liftBufferPointer(_ value: Operand, length: Operand) -> Operand {
.call(
"UnsafeBufferPointer",
arguments: [
("start", value), ("count", .call("Int", arguments: [length])),
])
}
func liftList(pointer: Operand, length: Operand, element: WITType, loadElement: (Pointer) throws -> Operand) throws -> Operand {
let loadElementVar = builder.variable("loadElement")
try printer.write(line: "let \(loadElementVar): (UnsafeRawPointer) -> \(element.qualifiedSwiftName(mapping: definitionMapping)) = {")
try printer.indent {
// NOTE: `loadElement` can print statements
let loaded = try loadElement(.init(basePointerVar: "$0", offset: 0))
printer.write(line: "return \(loaded)")
}
printer.write(line: "}")
return .call(
"Prelude.liftList",
arguments: [
("pointer", .call("UInt32", arguments: [pointer])),
("length", .call("UInt32", arguments: [length])),
("elementSize", .literal(CanonicalABI.size(type: element).description)),
("loadElement", .variable(loadElementVar)),
])
}
}
struct GuestStaticCanonicalLowering: StaticCanonicalLowering {
typealias Operand = StaticMetaOperand
typealias Pointer = StaticMetaPointer
var printer: SourcePrinter
var builder: SwiftFunctionBuilder
let definitionMapping: DefinitionMapping
func lowerString(_ value: Operand, encoding: String) throws -> (pointer: Operand, length: Operand) {
let stringBufferVar = builder.variable("stringBuffer")
printer.write(line: "let \(stringBufferVar) = Array(\(value).utf8)")
let operand = StaticMetaOperand.variable(stringBufferVar)
return (
.call("Prelude.leakUnderlyingBuffer", arguments: [operand]),
.call("UInt32", arguments: [.accessField(operand, name: "count")])
)
}
func lowerList(
_ value: Operand, element: WITType,
storeElement: (Pointer, Operand) throws -> Void
) throws -> (pointer: Operand, length: Operand) {
let storeElementVar = builder.variable("storeElement")
try printer.write(line: "let \(storeElementVar): (\(element.qualifiedSwiftName(mapping: definitionMapping)), UnsafeMutableRawPointer) -> Void = {")
try printer.indent {
try storeElement(Pointer(basePointerVar: "$1", offset: 0), .variable("$0"))
}
printer.write(line: "}")
let lowered = Operand.call(
"Prelude.lowerList",
arguments: [
(nil, value),
("elementSize", .literal(CanonicalABI.size(type: element).description)),
("elementAlignment", .literal(CanonicalABI.alignment(type: element).description)),
("storeElement", .variable(storeElementVar)),
])
let loweredVar = StaticMetaOperand.variable(builder.variable("stringLowered"))
printer.write(line: "let \(loweredVar) = \(lowered)")
return (
lowerUInt32(.accessField(loweredVar, name: "pointer")),
lowerUInt32(.accessField(loweredVar, name: "length"))
)
}
}
struct GuestExportFunction {
let function: FunctionSyntax
let builder = SwiftFunctionBuilder()
let definitionMapping: DefinitionMapping
let name: CanonicalFunctionName
let implementation: String
func print(
typeResolver: (TypeReprSyntax) throws -> WITType,
printer: SourcePrinter
) throws {
let coreSignature = try CanonicalABI.flattenSignature(
function: function,
typeResolver: typeResolver
)
// TODO: Use `@_expose(wasm)` once it will be merged
printer.write(line: "@_cdecl(\"\(name.abiName)\")")
printer.write(
line: renderSwiftFunctionDecl(
name: "__export_\(name.uniqueSwiftName)",
coreSignature: coreSignature
) + " {"
)
try printer.indent {
try printBody(
coreSignature: coreSignature, typeResolver: typeResolver, printer: printer
)
}
printer.write(line: "}")
if coreSignature.isIndirectResult {
try printPostReturn(coreSignature: coreSignature, typeResolver: typeResolver, parentPrinter: printer)
}
}
func printBody(
coreSignature: CanonicalABI.CoreSignature,
typeResolver: (TypeReprSyntax) throws -> WITType,
printer: SourcePrinter
) throws {
// Before executing any code, run static constructor (a.k.a ctors) functions
// to initialize wasi-libc, Swift runtime, and so on.
printer.write(line: "Prelude.initializeOnce()")
var arguments = coreSignature.parameters.map {
StaticMetaOperand.variable($0.swiftLabelName)
}.makeIterator()
for parameter in function.parameters {
let type = try typeResolver(parameter.type)
var lifting = GuestStaticCanonicalLifting(
printer: printer, builder: builder,
definitionMapping: definitionMapping
)
var loading = StaticCanonicalLoading(printer: printer, builder: builder)
let rValue = try WIT.CanonicalABI.lift(
type: type, coreValues: &arguments, lifting: &lifting, loading: &loading
)
try printer.write(line: "let \(SwiftName.makeName(parameter.name)) = \(rValue)")
}
let resultVar = builder.variable("result")
if !function.results.types.isEmpty {
printer.write(line: "let \(resultVar) = \(implementation)(")
} else {
// Don't assign the returned void value to variable to suppress warnings
printer.write(line: "\(implementation)(")
}
try printer.indent {
for (i, parameter) in function.parameters.enumerated() {
let isEnd = i == function.parameters.count - 1
let paramName = try ConvertCase.camelCase(parameter.name)
printer.write(line: "\(paramName): \(paramName)\(isEnd ? "" : ",")")
}
}
printer.write(line: ")")
var lowering = GuestStaticCanonicalLowering(
printer: printer,
builder: builder,
definitionMapping: definitionMapping
)
var storing = StaticCanonicalStoring(printer: printer, builder: builder, definitionMapping: definitionMapping)
if coreSignature.isIndirectResult {
let resultBuffer = builder.variable("resultBuffer")
for resultTypeRepr in function.results.types {
let type = try typeResolver(resultTypeRepr)
printer.write(line: "let \(resultBuffer) = UnsafeMutableRawPointer.allocate(byteCount: \(CanonicalABI.size(type: type)), alignment: \(CanonicalABI.alignment(type: type)))")
let basePointer = StaticCanonicalStoring.Pointer(
basePointerVar: resultBuffer, offset: 0
)
try CanonicalABI.store(
type: type, value: .variable(resultVar),
pointer: basePointer, storing: &storing, lowering: &lowering
)
}
printer.write(line: "return Int32(UInt(bitPattern: \(resultBuffer)))")
} else {
var allResultValues: [StaticMetaOperand] = []
for resultTypeRepr in function.results.types {
let type = try typeResolver(resultTypeRepr)
let resultValues = try CanonicalABI.lower(type: type, value: .variable(resultVar), lowering: &lowering, storing: &storing)
// Number of result values should be 0 or 1
guard resultValues.count <= 1 else { fatalError("Lowered return value should not have multiple core values") }
allResultValues.append(contentsOf: resultValues)
}
// If the original signature already doesn't have a result type, resultVar is unavailable
if allResultValues.isEmpty && !function.results.types.isEmpty {
// Suppress unused variable warning
printer.write(line: "_ = \(resultVar)")
}
printer.write(line: "return (\(allResultValues.map(\.description).joined(separator: ", ")))")
}
}
func printPostReturn(
coreSignature: CanonicalABI.CoreSignature,
typeResolver: (TypeReprSyntax) throws -> WITType,
parentPrinter: SourcePrinter
) throws {
let builder = SwiftFunctionBuilder()
let printer = SourcePrinter()
let resultTypes = try function.results.types.map(typeResolver)
// TODO: Use `@_expose(wasm)` once it will be merged
printer.write(line: "@_cdecl(\"cabi_post_\(name.abiName)\")")
printer.write(line: "func __cabi_post_return_\(name.uniqueSwiftName)(")
let argPointerVar = builder.variable("arg")
printer.indent {
assert(coreSignature.results.count == 1, "Currently only single result is supported by Canonical ABI")
printer.write(line: argPointerVar + ": UnsafeMutableRawPointer")
}
printer.write(line: ") {")
var needsDeallocation = false
try printer.indent {
let deallocation = StaticCanonicalDeallocation(printer: printer, builder: builder)
let loading = StaticCanonicalLoading(printer: printer, builder: builder)
for (resultType, offset) in CanonicalABI.fieldOffsets(fields: resultTypes) {
let pointer = StaticMetaPointer(basePointerVar: argPointerVar, offset: offset)
let result = try CanonicalABI.deallocate(
type: resultType, pointer: pointer,
deallocation: deallocation, loading: loading
)
needsDeallocation = needsDeallocation || result
}
}
printer.write(line: "}")
if needsDeallocation {
parentPrinter.write(multiline: printer.contents)
}
}
}
extension CanonicalABI.SignatureSegment {
fileprivate var swiftLabelName: String {
ConvertCase.camelCase(label.map(ConvertCase.camelCase))
}
}
private func renderSwiftFunctionDecl(
name: String,
coreSignature: CanonicalABI.CoreSignature
) -> String {
var result = "func \(name)("
result += coreSignature.parameters.map { param in
param.swiftLabelName + ": " + param.type.swiftType
}.joined(separator: ", ")
result += ")"
switch coreSignature.results.count {
case 0: break
case 1:
result += " -> " + coreSignature.results[0].type.swiftType
default:
result += " -> ("
result += coreSignature.results.map { result in
result.swiftLabelName + ": " + result.type.swiftType
}.joined(separator: ", ")
result += ")"
}
return result
}
extension CanonicalABI.CoreType {
fileprivate var swiftType: String {
switch self {
case .i32: return "Int32"
case .i64: return "Int64"
case .f32: return "Float"
case .f64: return "Double"
}
}
}
|
