BridgeJS: Unify thunk argument preparation

Author: krodak

Benchmarks/Sources/Generated/BridgeJS.swift

@@ -179,8 +179,11 @@ public func _bjs_PlayBridgeJS_init() -> UnsafeMutableRawPointer {
 @_cdecl("bjs_PlayBridgeJS_updateDetailed")
 public func _bjs_PlayBridgeJS_updateDetailed(_ _self: UnsafeMutableRawPointer, _ swiftSourceBytes: Int32, _ swiftSourceLength: Int32, _ dtsSourceBytes: Int32, _ dtsSourceLength: Int32) -> Void {
     #if arch(wasm32)
+    let _tmp_dtsSource = String.bridgeJSLiftParameter(dtsSourceBytes, dtsSourceLength)
+    let _tmp_swiftSource = String.bridgeJSLiftParameter(swiftSourceBytes, swiftSourceLength)
+    let _tmp__self = PlayBridgeJS.bridgeJSLiftParameter(_self)
     do {
-        let ret = try PlayBridgeJS.bridgeJSLiftParameter(_self).updateDetailed(swiftSource: String.bridgeJSLiftParameter(swiftSourceBytes, swiftSourceLength), dtsSource: String.bridgeJSLiftParameter(dtsSourceBytes, dtsSourceLength))
+        let ret = try _tmp__self.updateDetailed(swiftSource: _tmp_swiftSource, dtsSource: _tmp_dtsSource)
         return ret.bridgeJSLowerReturn()
     } catch let error {
         if let error = error.thrownValue.object {

Examples/PlayBridgeJS/Sources/PlayBridgeJS/Generated/BridgeJS.swift

@@ -112,11 +112,14 @@ public struct ClosureCodegen {
 
         let helperEnumDecl: DeclSyntax = "\(raw: helperEnumDeclPrinter.lines.joined(separator: "\n"))"
 
-        let initAccessModifier = accessLevel.modifierKeyword.map { "\($0) " } ?? ""
+        let accessModifier = accessLevel.modifierKeyword.map { "\($0) " } ?? ""
+        let declaration = signature.sendingParameters ? "static func sending" : "init"
+        let returnClause = signature.sendingParameters ? " -> Self" : ""
+        let initializer = signature.sendingParameters ? "Self" : "self.init"
         let typedClosureExtension: DeclSyntax = """
             extension JSTypedClosure where Signature == \(raw: swiftClosureType) {
-                \(raw: initAccessModifier)init(fileID: StaticString = #fileID, line: UInt32 = #line, _ body: @escaping \(raw: swiftClosureType)) {
-                    self.init(
+                \(raw: accessModifier)\(raw: declaration)(fileID: StaticString = #fileID, line: UInt32 = #line, _ body: @escaping \(raw: swiftClosureType))\(raw: returnClause) {
+                    \(raw: initializer)(
                         makeClosure: \(raw: externABIName),
                         body: body,
                         fileID: fileID,
@@ -135,149 +138,22 @@ public struct ClosureCodegen {
         let swiftClosureType = swiftClosureType(for: signature)
         let boxType = "_BridgeJSTypedClosureBox<\(swiftClosureType)>"
         let abiName = "invoke_swift_closure_\(signature.moduleName)_\(signature.mangleName)"
-
-        // Build ABI parameters directly with WasmCoreType (no string conversion needed)
-        var abiParams: [(name: String, type: WasmCoreType)] = [("boxPtr", .pointer)]
-        var liftedParams: [String] = []
-
-        for (index, paramType) in signature.parameters.enumerated() {
-            let paramName = "param\(index)"
-            let liftInfo = try paramType.liftParameterInfo()
-
-            for (argName, wasmType) in liftInfo.parameters {
-                let fullName =
-                    liftInfo.parameters.count > 1 ? "\(paramName)\(argName.capitalizedFirstLetter)" : paramName
-                abiParams.append((fullName, wasmType))
-            }
-
-            let argNames = liftInfo.parameters.map { (argName, _) in
-                liftInfo.parameters.count > 1 ? "\(paramName)\(argName.capitalizedFirstLetter)" : paramName
-            }
-            liftedParams.append(
-                "\(paramType.swiftType).bridgeJSLiftParameter(\(argNames.joined(separator: ", ")))"
-            )
-        }
-
-        let tryPrefix = signature.isThrows ? "try " : ""
-        let closureCallExpr = ExprSyntax("\(raw: tryPrefix)closure(\(raw: liftedParams.joined(separator: ", ")))")
-        let asyncTryPrefix = (signature.isThrows ? "try " : "") + "await "
-        let asyncClosureCallExpr = ExprSyntax(
-            "\(raw: asyncTryPrefix)closure(\(raw: liftedParams.joined(separator: ", ")))"
+        let builder = try ExportSwift.ExportedThunkBuilder(
+            effects: Effects(isAsync: signature.isAsync, isThrows: signature.isThrows),
+            returnType: signature.returnType
         )
-
-        let abiReturnWasmType =
-            signature.isAsync
-            ? try BridgeType.jsObject(nil).loweringReturnInfo().returnType
-            : try signature.returnType.loweringReturnInfo().returnType
-
-        // Build signature using SwiftSignatureBuilder
-        let funcSignature = SwiftSignatureBuilder.buildABIFunctionSignature(
-            abiParameters: abiParams,
-            returnType: abiReturnWasmType
+        builder.abiParameterSignatures.append(("boxPtr", .pointer))
+        builder.parameterBindings.append(
+            "let closure = Unmanaged<\(raw: boxType)>.fromOpaque(boxPtr).takeUnretainedValue().closure"
         )
-
-        let emitCallAndLower: (CodeFragmentPrinter) -> Void = { printer in
-            if signature.returnType == .void {
-                printer.write(closureCallExpr.description)
-            } else {
-                printer.write("let result = \(closureCallExpr)")
-                switch signature.returnType {
-                case .swiftProtocol(let protocolName):
-                    printer.write(
-                        "return _bridgeJSUnwrapProtocolExportable(result, \"\(protocolName)\").bridgeJSLowerAsProtocolReturn()"
-                    )
-                case .nullable(.swiftProtocol(let protocolName), _):
-                    printer.write("if let result {")
-                    printer.indent {
-                        printer.write(
-                            "_swift_js_return_optional_object(1, _bridgeJSUnwrapProtocolExportable(result, \"\(protocolName)\").bridgeJSLowerAsProtocolReturn())"
-                        )
-                    }
-                    printer.write("} else {")
-                    printer.indent {
-                        printer.write("_swift_js_return_optional_object(0, 0)")
-                    }
-                    printer.write("}")
-                default:
-                    printer.write("return result.bridgeJSLowerReturn()")
-                }
-            }
-        }
-
-        let emitAsyncCallAndLower: (CodeFragmentPrinter) -> Void = { printer in
-            printer.write("let closure = Unmanaged<\(boxType)>.fromOpaque(boxPtr).takeUnretainedValue().closure")
-            let resolveType = signature.returnType
-            let resolveName = "Promise_resolve_\(resolveType.mangleTypeName)"
-            let rejectName = "Promise_reject"
-            let closureHead: String
-            if signature.isThrows {
-                let returnSpelling = resolveType == .void ? "" : " -> \(resolveType.closureSwiftType)"
-                closureHead = " () async throws(JSException)\(returnSpelling) in"
-            } else {
-                closureHead = ""
-            }
-            printer.write("return _bjs_makePromise(resolve: \(resolveName), reject: \(rejectName)) {\(closureHead)")
-            printer.indent {
-                if resolveType == .void {
-                    printer.write(asyncClosureCallExpr.description)
-                } else {
-                    printer.write("return \(asyncClosureCallExpr)")
-                }
-            }
-            printer.write("}")
-        }
-
-        let catchPlaceholderStmt = abiReturnWasmType?.swiftReturnPlaceholderStmt
-
-        // Build function declaration using helper
-        let funcDecl = SwiftCodePattern.buildExposedFunctionDecl(
-            abiName: abiName,
-            signature: funcSignature
-        ) { printer in
-            if signature.isAsync {
-                emitAsyncCallAndLower(printer)
-            } else if signature.isThrows {
-                printer.write(
-                    "let closure = Unmanaged<\(boxType)>.fromOpaque(boxPtr).takeUnretainedValue().closure"
-                )
-                printer.write("do {")
-                printer.indent {
-                    emitCallAndLower(printer)
-                }
-                printer.write("} catch let error {")
-                printer.indent {
-                    printer.write("if let error = error.thrownValue.object {")
-                    printer.indent {
-                        printer.write("withExtendedLifetime(error) {")
-                        printer.indent {
-                            printer.write("_swift_js_throw(Int32(bitPattern: $0.id))")
-                        }
-                        printer.write("}")
-                    }
-                    printer.write("} else {")
-                    printer.indent {
-                        printer.write("let jsError = JSError(message: error.description)")
-                        printer.write("withExtendedLifetime(jsError.jsObject) {")
-                        printer.indent {
-                            printer.write("_swift_js_throw(Int32(bitPattern: $0.id))")
-                        }
-                        printer.write("}")
-                    }
-                    printer.write("}")
-                    if let catchPlaceholderStmt {
-                        printer.write(catchPlaceholderStmt)
-                    }
-                }
-                printer.write("}")
-            } else {
-                printer.write(
-                    "let closure = Unmanaged<\(boxType)>.fromOpaque(boxPtr).takeUnretainedValue().closure"
-                )
-                emitCallAndLower(printer)
-            }
+        for (index, paramType) in signature.parameters.enumerated() {
+            try builder.liftParameter(
+                param: Parameter(label: nil, name: "param\(index)", type: paramType)
+            )
         }
-
-        return DeclSyntax(funcDecl)
+        builder.call(name: "closure", returnType: signature.returnType)
+        try builder.lowerReturnValue(returnType: signature.returnType)
+        return builder.render(abiName: abiName)
     }
 
     public func renderSupport(for skeleton: BridgeJSSkeleton) throws -> String? {

Plugins/BridgeJS/Sources/BridgeJSCore/ClosureCodegen.swift

@@ -190,8 +190,7 @@ public class ExportSwift {
         /// helper. Set for every `async` thunk.
         var asyncResolveReturnType: BridgeType?
 
-        /// Stack-using parameter lifts hoisted ahead of the deferred async closure.
-        var asyncHoistedBindings: [CodeBlockItemSyntax] = []
+        var parameterBindings: [CodeBlockItemSyntax] = []
 
         init(effects: Effects, returnType: BridgeType) throws {
             self.effects = effects
@@ -254,7 +253,10 @@ public class ExportSwift {
                 )
             }
 
-            liftedParameterExprs.append(liftingExpr)
+            let varName = "_tmp_\(param.name)"
+            let binding: CodeBlockItemSyntax = "let \(raw: varName) = \(liftingExpr)"
+            parameterBindings.append(binding)
+            liftedParameterExprs.append(ExprSyntax(DeclReferenceExprSyntax(baseName: .identifier(varName))))
             for (name, type) in zip(argumentsToLift, liftingInfo.parameters.map { $0.type }) {
                 abiParameterSignatures.append((name, type))
             }
@@ -310,7 +312,6 @@ public class ExportSwift {
         }
 
         func call(name: String, returnType: BridgeType) {
-            generateParameterLifting()
             let item = renderCallStatement(callee: "\(raw: name)", returnType: returnType)
             append(item)
         }
@@ -326,48 +327,13 @@ public class ExportSwift {
 
         func callMethod(methodName: String, returnType: BridgeType) {
             let (_, selfExpr) = removeFirstLiftedParameter()
-            generateParameterLifting()
             let item = renderCallStatement(
                 callee: "\(raw: selfExpr).\(raw: methodName)",
                 returnType: returnType
             )
             append(item)
         }
 
-        /// Generates intermediate variables for stack-using parameters if needed for LIFO compatibility
-        private func generateParameterLifting() {
-            let stackParamIndices = parameters.enumerated().compactMap { index, param -> Int? in
-                param.type.isStackUsingParameter ? index : nil
-            }
-
-            if effects.isAsync {
-                // Drain stack parameters before the deferred `Task` or the shared stack is corrupted.
-                for index in stackParamIndices.reversed() {
-                    let param = parameters[index]
-                    let expr = liftedParameterExprs[index]
-                    let varName = "_tmp_\(param.name)"
-                    var binding: CodeBlockItemSyntax = "let \(raw: varName) = \(expr)"
-                    if !asyncHoistedBindings.isEmpty {
-                        binding = binding.with(\.leadingTrivia, .newline)
-                    }
-                    asyncHoistedBindings.append(binding)
-                    liftedParameterExprs[index] = ExprSyntax(DeclReferenceExprSyntax(baseName: .identifier(varName)))
-                }
-                return
-            }
-
-            guard stackParamIndices.count > 1 else { return }
-
-            for index in stackParamIndices.reversed() {
-                let param = parameters[index]
-                let expr = liftedParameterExprs[index]
-                let varName = "_tmp_\(param.name)"
-
-                append("let \(raw: varName) = \(expr)")
-                liftedParameterExprs[index] = ExprSyntax(DeclReferenceExprSyntax(baseName: .identifier(varName)))
-            }
-        }
-
         func callPropertyGetter(propertyName: String, returnType: BridgeType) {
             let (_, selfExpr) = removeFirstLiftedParameter()
             if returnType == .void {
@@ -456,10 +422,11 @@ public class ExportSwift {
         /// so the body must also read the captured value.
         /// See: https://github.com/swiftlang/swift/issues/89320
         private var asyncThrowsBodyForcesCapture: Bool {
-            effects.isThrows && abiParameterSignatures.isEmpty && asyncHoistedBindings.isEmpty
+            effects.isThrows && parameterBindings.isEmpty
         }
 
         func render(abiName: String) -> DeclSyntax {
+            var bindings = Array(parameterBindings.reversed())
             let body: CodeBlockItemListSyntax
             if effects.isAsync, let resolveType = asyncResolveReturnType {
                 let resolveName = "Promise_resolve_\(resolveType.mangleTypeName)"
@@ -468,17 +435,15 @@ public class ExportSwift {
                     returnSpelling: resolveType.swiftType,
                     forcesCapture: forcesCapture
                 )
-                var hoistedBindings = asyncHoistedBindings
                 var bodyItems = self.body
                 if forcesCapture {
-                    hoistedBindings.append("let __bjs_capture = 0")
+                    bindings.append("let __bjs_capture = 0")
                     if !bodyItems.isEmpty {
                         bodyItems[0] = bodyItems[0].with(\.leadingTrivia, .newline)
                     }
                     bodyItems.insert("_ = __bjs_capture", at: 0)
                 }
                 body = """
-                    \(CodeBlockItemListSyntax(hoistedBindings))
                     return _bjs_makePromise(resolve: \(raw: resolveName), reject: Promise_reject) {\(raw: closureHead)
                         \(CodeBlockItemListSyntax(bodyItems))
                     }
@@ -504,6 +469,10 @@ public class ExportSwift {
             } else {
                 body = CodeBlockItemListSyntax(self.body)
             }
+            let preparedBody: CodeBlockItemListSyntax = """
+                \(CodeBlockItemListSyntax(bindings.map { $0.with(\.leadingTrivia, .newline) }))
+                \(body)
+                """
             // Build function signature using SwiftSignatureBuilder
             let signature = SwiftSignatureBuilder.buildABIFunctionSignature(
                 abiParameters: abiParameterSignatures,
@@ -515,7 +484,7 @@ public class ExportSwift {
                 abiName: abiName,
                 signature: signature
             ) { printer in
-                printer.write(multilineString: body.description)
+                printer.write(multilineString: preparedBody.description)
             }
 
             return DeclSyntax(funcDecl)
@@ -1744,19 +1713,6 @@ extension BridgeType {
         return false
     }
 
-    var isStackUsingParameter: Bool {
-        switch self {
-        case .swiftStruct, .array, .dictionary, .associatedValueEnum:
-            return true
-        case .nullable(let wrapped, _):
-            return wrapped.isStackUsingParameter
-        case .alias(_, let underlying):
-            return underlying.isStackUsingParameter
-        default:
-            return false
-        }
-    }
-
     struct LiftingIntrinsicInfo: Sendable {
         let parameters: [(name: String, type: WasmCoreType)]
 

Plugins/BridgeJS/Sources/BridgeJSCore/ExportSwift.swift

@@ -339,7 +339,7 @@ public struct ImportTS {
             body = CodeFragmentPrinter()
 
             let tryKeyword = effects.isThrows ? "try" : "try!"
-            let rejectFactory = "makeRejectClosure: { JSTypedClosure<(sending JSValue) -> Void>($0) }"
+            let rejectFactory = "makeRejectClosure: { JSTypedClosure<(sending JSValue) -> Void>.sending($0) }"
             if returnType == .void {
                 let resolveFactory = "makeResolveClosure: { JSTypedClosure<() -> Void>($0) }"
                 body.write(
@@ -348,7 +348,7 @@ public struct ImportTS {
             } else {
                 let resolveSwiftType = returnType.closureSwiftType
                 let resolveFactory =
-                    "makeResolveClosure: { JSTypedClosure<(sending \(resolveSwiftType)) -> Void>($0) }"
+                    "makeResolveClosure: { JSTypedClosure<(sending \(resolveSwiftType)) -> Void>.sending($0) }"
                 body.write(
                     "let resolved = \(tryKeyword) await _bjs_awaitPromise(\(resolveFactory), \(rejectFactory)) { resolveRef, rejectRef in"
                 )