Make targetSwiftPackagePath optional for Wasm Swift SDK generation (#242)

This allows generating Swift SDKs for Wasm that do not have support for targeting Swift (C/C++ only).

Author: jakepetroules

Sources/GeneratorCLI/GeneratorCLI.swift

@@ -420,15 +420,12 @@ extension GeneratorCLI {
     }
 
     func run() async throws {
-      guard let targetSwiftPackagePath = generatorOptions.targetSwiftPackagePath else {
-        throw StringError("Missing expected argument '--target-swift-package-path'")
-      }
       let recipe = try WebAssemblyRecipe(
         hostSwiftPackage: generatorOptions.hostSwiftPackagePath.map {
           let hostTriples = try self.generatorOptions.deriveHostTriples()
           return WebAssemblyRecipe.HostToolchainPackage(path: FilePath($0), triples: hostTriples)
         },
-        targetSwiftPackagePath: FilePath(targetSwiftPackagePath),
+        targetSwiftPackagePath: generatorOptions.targetSwiftPackagePath.map { FilePath($0) },
         wasiSysroot: FilePath(self.wasiSysroot),
         swiftVersion: self.generatorOptions.swiftVersion,
         logger: loggerWithLevel(from: self.generatorOptions)

Sources/SwiftSDKGenerator/SwiftSDKRecipes/WebAssemblyRecipe.swift

@@ -17,7 +17,9 @@ import struct SystemPackage.FilePath
 
 package struct WebAssemblyRecipe: SwiftSDKRecipe {
   let hostSwiftPackage: HostToolchainPackage?
-  let targetSwiftPackagePath: FilePath
+
+  /// Optional to allow creating WebAssembly Swift SDKs that don't include Swift support and therefore can only target C/C++.
+  let targetSwiftPackagePath: FilePath?
   let wasiSysroot: FilePath
   let swiftVersion: String
   package let logger: Logger
@@ -34,7 +36,7 @@ package struct WebAssemblyRecipe: SwiftSDKRecipe {
 
   package init(
     hostSwiftPackage: HostToolchainPackage?,
-    targetSwiftPackagePath: FilePath,
+    targetSwiftPackagePath: FilePath?,
     wasiSysroot: FilePath,
     swiftVersion: String,
     logger: Logger
@@ -47,7 +49,10 @@ package struct WebAssemblyRecipe: SwiftSDKRecipe {
   }
 
   package var defaultArtifactID: String {
-    "\(self.swiftVersion)_wasm"
+    if hostSwiftPackage == nil && targetSwiftPackagePath == nil {
+      return "wasm"
+    }
+    return "\(self.swiftVersion)_wasm"
   }
 
   package let shouldSupportEmbeddedSwift = true
@@ -134,74 +139,74 @@ package struct WebAssemblyRecipe: SwiftSDKRecipe {
     httpClient: some HTTPClientProtocol
   ) async throws -> SwiftSDKProduct {
     let pathsConfiguration = generator.pathsConfiguration
-    let targetSwiftLibPath = self.targetSwiftPackagePath.appending("usr/lib")
-
-    logger.info("Copying Swift binaries for the host triple...")
     var hostTriples: [Triple]? = nil
-    if let hostSwiftPackage {
-      hostTriples = hostSwiftPackage.triples
-      try await generator.rsync(
-        from: hostSwiftPackage.path.appending("usr"),
-        to: pathsConfiguration.toolchainDirPath
-      )
+    if let targetSwiftLibPath = self.targetSwiftPackagePath?.appending("usr/lib") {
+      logger.info("Copying Swift binaries for the host triple...")
+      if let hostSwiftPackage {
+        hostTriples = hostSwiftPackage.triples
+        try await generator.rsync(
+          from: hostSwiftPackage.path.appending("usr"),
+          to: pathsConfiguration.toolchainDirPath
+        )
+
+        logger.info("Removing unused toolchain components...")
+        let liblldbNames: [String] = try await {
+          let libDirPath = pathsConfiguration.toolchainDirPath.appending("usr/lib")
+          guard await generator.doesFileExist(at: libDirPath) else {
+            return []
+          }
+          return try await generator.contentsOfDirectory(at: libDirPath).filter { dirEntry in
+            // liblldb is version suffixed: liblldb.so.17.0.0
+            dirEntry.hasPrefix("liblldb")
+          }
+        }()
+        try await generator.removeToolchainComponents(
+          pathsConfiguration.toolchainDirPath,
+          platforms: unusedTargetPlatforms,
+          libraries: unusedHostLibraries + liblldbNames,
+          binaries: unusedHostBinaries + ["lldb", "lldb-argdumper", "lldb-server"]
+        )
+        // Merge target Swift package with the host package.
+        try await self.mergeTargetSwift(from: targetSwiftLibPath, generator: generator)
+      } else {
+        // Simply copy the target Swift package into the Swift SDK bundle when building host-agnostic Swift SDK.
+        try await generator.createDirectoryIfNeeded(
+          at: pathsConfiguration.toolchainDirPath.appending("usr")
+        )
+        try await generator.copy(
+          from: targetSwiftLibPath,
+          to: pathsConfiguration.toolchainDirPath.appending("usr/lib")
+        )
+      }
 
-      logger.info("Removing unused toolchain components...")
-      let liblldbNames: [String] = try await {
-        let libDirPath = pathsConfiguration.toolchainDirPath.appending("usr/lib")
-        guard await generator.doesFileExist(at: libDirPath) else {
-          return []
-        }
-        return try await generator.contentsOfDirectory(at: libDirPath).filter { dirEntry in
-          // liblldb is version suffixed: liblldb.so.17.0.0
-          dirEntry.hasPrefix("liblldb")
-        }
-      }()
-      try await generator.removeToolchainComponents(
-        pathsConfiguration.toolchainDirPath,
-        platforms: unusedTargetPlatforms,
-        libraries: unusedHostLibraries + liblldbNames,
-        binaries: unusedHostBinaries + ["lldb", "lldb-argdumper", "lldb-server"]
-      )
-      // Merge target Swift package with the host package.
-      try await self.mergeTargetSwift(from: targetSwiftLibPath, generator: generator)
-    } else {
-      // Simply copy the target Swift package into the SDK bundle when building host-agnostic SDK.
-      try await generator.createDirectoryIfNeeded(
-        at: pathsConfiguration.toolchainDirPath.appending("usr")
+      let autolinkExtractPath = pathsConfiguration.toolchainBinDirPath.appending(
+        "swift-autolink-extract"
       )
-      try await generator.copy(
-        from: targetSwiftLibPath,
-        to: pathsConfiguration.toolchainDirPath.appending("usr/lib")
-      )
-    }
 
-    let autolinkExtractPath = pathsConfiguration.toolchainBinDirPath.appending(
-      "swift-autolink-extract"
-    )
-
-    // WebAssembly object file requires `swift-autolink-extract`
-    if await !generator.doesFileExist(at: autolinkExtractPath),
-      await generator.doesFileExist(
-        at: generator.pathsConfiguration.toolchainBinDirPath.appending("swift")
-      )
-    {
-      logger.info("Fixing `swift-autolink-extract` symlink...")
-      try await generator.createSymlink(at: autolinkExtractPath, pointingTo: "swift")
-    }
+      // WebAssembly object file requires `swift-autolink-extract`
+      if await !generator.doesFileExist(at: autolinkExtractPath),
+        await generator.doesFileExist(
+          at: generator.pathsConfiguration.toolchainBinDirPath.appending("swift")
+        )
+      {
+        logger.info("Fixing `swift-autolink-extract` symlink...")
+        try await generator.createSymlink(at: autolinkExtractPath, pointingTo: "swift")
+      }
 
-    // TODO: Remove this once we drop support for Swift 6.2
-    // Embedded Swift looks up clang compiler-rt in a different path.
-    let embeddedCompilerRTPath = pathsConfiguration.toolchainDirPath.appending(
-      "usr/lib/swift/clang/lib/wasip1"
-    )
-    if await !generator.doesFileExist(at: embeddedCompilerRTPath) {
-      try await generator.createSymlink(
-        at: embeddedCompilerRTPath,
-        pointingTo: "../../../swift_static/clang/lib/wasi"
+      // TODO: Remove this once we drop support for Swift 6.2
+      // Embedded Swift looks up clang compiler-rt in a different path.
+      let embeddedCompilerRTPath = pathsConfiguration.toolchainDirPath.appending(
+        "usr/lib/swift/clang/lib/wasip1"
       )
+      if await !generator.doesFileExist(at: embeddedCompilerRTPath) {
+        try await generator.createSymlink(
+          at: embeddedCompilerRTPath,
+          pointingTo: "../../../swift_static/clang/lib/wasi"
+        )
+      }
     }
 
-    // Copy the WASI sysroot into the SDK bundle.
+    // Copy the WASI sysroot into the Swift SDK bundle.
     let sdkDirPath = pathsConfiguration.swiftSDKRootPath.appending("WASI.sdk")
     try await generator.rsyncContents(from: self.wasiSysroot, to: sdkDirPath)