Fix package access modifier in XCBuild support

Package.swift

@@ -4,7 +4,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2014-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2014-2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
@@ -349,7 +349,7 @@ let package = Package(
         .target(
             /** Support for building using Xcode's build system */
             name: "XCBuildSupport",
-            dependencies: ["SPMBuildCore", "PackageGraph"],
+            dependencies: ["DriverSupport", "SPMBuildCore", "PackageGraph"],
             exclude: ["CMakeLists.txt", "CODEOWNERS"]
         ),
         .target(

Sources/Build/BuildDescription/SwiftTargetBuildDescription.swift

@@ -11,10 +11,13 @@
 //===----------------------------------------------------------------------===//
 
 import Basics
+
 import Foundation
 import PackageGraph
 import PackageLoading
 import PackageModel
+
+@_spi(SwiftPMInternal)
 import SPMBuildCore
 
 #if USE_IMPL_ONLY_IMPORTS
@@ -419,18 +422,6 @@ public final class SwiftTargetBuildDescription {
         try self.fileSystem.writeIfChanged(path: path, string: content)
     }
 
-    private func packageNameArgumentIfSupported(with pkg: ResolvedPackage, packageAccess: Bool) -> [String] {
-        let flag = "-package-name"
-        if pkg.manifest.usePackageNameFlag,
-           DriverSupport.checkToolchainDriverFlags(flags: [flag], toolchain:  self.buildParameters.toolchain, fileSystem: self.fileSystem) {
-            if packageAccess {
-                let pkgID = pkg.identity.description.spm_mangledToC99ExtendedIdentifier()
-                return [flag, pkgID]
-            } 
-        }
-        return []
-    }
-
     private func macroArguments() throws -> [String] {
         var args = [String]()
 
@@ -450,7 +441,14 @@ public final class SwiftTargetBuildDescription {
         #endif
 
         // If we're using an OSS toolchain, add the required arguments bringing in the plugin server from the default toolchain if available.
-        if self.buildParameters.toolchain.isSwiftDevelopmentToolchain, DriverSupport.checkSupportedFrontendFlags(flags: ["-external-plugin-path"], toolchain: self.buildParameters.toolchain, fileSystem: self.fileSystem), let pluginServer = try self.buildParameters.toolchain.swiftPluginServerPath {
+        if self.buildParameters.toolchain.isSwiftDevelopmentToolchain, 
+            DriverSupport.checkSupportedFrontendFlags(
+                flags: ["-external-plugin-path"],
+                toolchain: self.buildParameters.toolchain,
+                fileSystem: self.fileSystem
+            ), 
+            let pluginServer = try self.buildParameters.toolchain.swiftPluginServerPath
+        {
             let toolchainUsrPath = pluginServer.parentDirectory.parentDirectory
             let pluginPathComponents = ["lib", "swift", "host", "plugins"]
 
@@ -631,7 +629,10 @@ public final class SwiftTargetBuildDescription {
             args += ["-user-module-version", version.description]
         }
 
-        args += self.packageNameArgumentIfSupported(with: self.package, packageAccess: self.target.packageAccess)
+        args += self.package.packageNameArgument(
+            target: self.target,
+            isPackageNameSupported: self.buildParameters.driverParameters.isPackageAccessModifierSupported
+        )
         args += try self.macroArguments()
 
         // rdar://117578677
@@ -656,7 +657,12 @@ public final class SwiftTargetBuildDescription {
 
         result.append("-module-name")
         result.append(self.target.c99name)
-        result.append(contentsOf: packageNameArgumentIfSupported(with: self.package, packageAccess: self.target.packageAccess))
+        result.append(
+            contentsOf: self.package.packageNameArgument(
+                target: self.target,
+                isPackageNameSupported: self.buildParameters.driverParameters.isPackageAccessModifierSupported
+            )
+        )
         if !scanInvocation {
             result.append("-emit-dependencies")
 

Sources/CoreCommands/SwiftTool.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2014-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2014-2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
@@ -23,8 +23,11 @@ import SPMBuildCore
 import Workspace
 
 #if USE_IMPL_ONLY_IMPORTS
-@_implementationOnly import DriverSupport
+@_implementationOnly
+@_spi(SwiftPMInternal)
+import DriverSupport
 #else
+@_spi(SwiftPMInternal)
 import DriverSupport
 #endif
 
@@ -757,7 +760,11 @@ public final class SwiftTool {
                 enableParseableModuleInterfaces: options.build.shouldEnableParseableModuleInterfaces,
                 explicitTargetDependencyImportCheckingMode: options.build.explicitTargetDependencyImportCheck.modeParameter,
                 useIntegratedSwiftDriver: options.build.useIntegratedSwiftDriver,
-                useExplicitModuleBuild: options.build.useExplicitModuleBuild
+                useExplicitModuleBuild: options.build.useExplicitModuleBuild,
+                isPackageAccessModifierSupported: DriverSupport.isPackageNameSupported(
+                    toolchain: toolchain,
+                    fileSystem: self.fileSystem
+                )
             ),
             linkingParameters: .init(
                 linkerDeadStrip: options.linker.linkerDeadStrip,

Sources/DriverSupport/DriverSupportUtils.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2022 Apple Inc. and the Swift project authors
+// Copyright (c) 2022-2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
@@ -20,7 +20,7 @@ import struct TSCBasic.ProcessResult
 public enum DriverSupport {
     private static var flagsMap = ThreadSafeBox<[String: Set<String>]>()
 
-    // This checks _frontend_ supported flags, which are not necessarily supported in the driver.
+    /// This checks _frontend_ supported flags, which are not necessarily supported in the driver.
     public static func checkSupportedFrontendFlags(
         flags: Set<String>,
         toolchain: PackageModel.Toolchain,
@@ -54,7 +54,7 @@ public enum DriverSupport {
     // This checks if given flags are supported in the built-in toolchain driver. Currently
     // there's no good way to get the supported flags from it, so run `swiftc -h` directly
     // to get the flags and cache the result.
-    public static func checkToolchainDriverFlags(
+    static func checkToolchainDriverFlags(
         flags: Set<String>,
         toolchain: PackageModel.Toolchain,
         fileSystem: FileSystem
@@ -83,4 +83,9 @@ public enum DriverSupport {
             return false
         }
     }
+
+    @_spi(SwiftPMInternal)
+    public static func isPackageNameSupported(toolchain: PackageModel.Toolchain, fileSystem: FileSystem) -> Bool {
+        DriverSupport.checkToolchainDriverFlags(flags: ["-package-name"], toolchain: toolchain, fileSystem: fileSystem)
+    }
 }

Sources/PackageModel/Target/SwiftTarget.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2014-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2014-2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information

Sources/SPMBuildCore/BuildParameters/BuildParameters+Driver.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift open source project
 //
-// Copyright (c) 2020-2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2020-2024 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See http://swift.org/LICENSE.txt for license information
@@ -25,13 +25,15 @@ extension BuildParameters {
             enableParseableModuleInterfaces: Bool = false,
             explicitTargetDependencyImportCheckingMode: TargetDependencyImportCheckingMode = .none,
             useIntegratedSwiftDriver: Bool = false,
-            useExplicitModuleBuild: Bool = false
+            useExplicitModuleBuild: Bool = false,
+            isPackageAccessModifierSupported: Bool = false
         ) {
             self.canRenameEntrypointFunctionName = canRenameEntrypointFunctionName
             self.enableParseableModuleInterfaces = enableParseableModuleInterfaces
             self.explicitTargetDependencyImportCheckingMode = explicitTargetDependencyImportCheckingMode
             self.useIntegratedSwiftDriver = useIntegratedSwiftDriver
             self.useExplicitModuleBuild = useExplicitModuleBuild
+            self.isPackageAccessModifierSupported = isPackageAccessModifierSupported
         }
 
         /// Whether to enable the entry-point-function-name feature.
@@ -45,11 +47,16 @@ extension BuildParameters {
         /// `.swiftmodule`s.
         public var enableParseableModuleInterfaces: Bool
 
-        /// Whether to use the integrated Swift driver rather than shelling out
+        /// Whether to use the integrated Swift Driver rather than shelling out
         /// to a separate process.
         public var useIntegratedSwiftDriver: Bool
 
         /// Whether to use the explicit module build flow (with the integrated driver).
         public var useExplicitModuleBuild: Bool
+
+        /// Whether the version of Swift Driver used in the currently selected toolchain
+        /// supports `-package-name` options.
+        @_spi(SwiftPMInternal)
+        public var isPackageAccessModifierSupported: Bool
     }
 }

Sources/SPMBuildCore/CMakeLists.txt

@@ -23,6 +23,7 @@ add_library(SPMBuildCore
   Plugins/PluginMessages.swift
   Plugins/PluginScriptRunner.swift
   PrebuildCommandResult.swift
+  ResolvedPackage+Extensions.swift
   Triple+Extensions.swift
   XCFrameworkMetadata.swift)
 # NOTE(compnerd) workaround for CMake not setting up include flags yet

Sources/SPMBuildCore/ResolvedPackage+Extensions.swift

@@ -0,0 +1,25 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2014-2024 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import struct PackageGraph.ResolvedPackage
+import struct PackageGraph.ResolvedTarget
+
+extension ResolvedPackage {
+    @_spi(SwiftPMInternal)
+    public func packageNameArgument(target: ResolvedTarget, isPackageNameSupported: Bool) -> [String] {
+        if self.manifest.usePackageNameFlag, target.packageAccess {
+            ["-package-name", self.identity.description.spm_mangledToC99ExtendedIdentifier()]
+        } else {
+            []
+        }
+    }
+}