Add initial support for object library product type

Author: owenv

Sources/SWBCore/CMakeLists.txt

@@ -138,6 +138,7 @@ add_library(SWBCore
   SpecImplementations/Tools/MergeInfoPlist.swift
   SpecImplementations/Tools/MkdirTool.swift
   SpecImplementations/Tools/ModulesVerifierTool.swift
+  SpecImplementations/Tools/ObjectLibraryAssembler.swift
   SpecImplementations/Tools/PLUtilTool.swift
   SpecImplementations/Tools/PrelinkedObjectLink.swift
   SpecImplementations/Tools/ProcessSDKImports.swift

Sources/SWBCore/PlannedTaskAction.swift

@@ -346,6 +346,7 @@ public protocol TaskActionCreationDelegate
     func createSignatureCollectionTaskAction() -> any PlannedTaskAction
     func createClangModuleVerifierInputGeneratorTaskAction() -> any PlannedTaskAction
     func createProcessSDKImportsTaskAction() -> any PlannedTaskAction
+    func createObjectLibraryAssemblerTaskAction() -> any PlannedTaskAction
 }
 
 extension TaskActionCreationDelegate {

Sources/SWBCore/SpecImplementations/LinkerSpec.swift

@@ -24,14 +24,16 @@ open class LinkerSpec : CommandLineToolSpec, @unchecked Sendable {
             case textBased
             case framework
             case object
+            case objectLibrary
 
             public var description: String {
                 switch self {
-                case .static:       return "static library"
-                case .dynamic:      return "dynamic library"
-                case .textBased:    return "text-based stub"
-                case .framework:    return "framework"
-                case .object:       return "object file"
+                case .static:        return "static library"
+                case .dynamic:       return "dynamic library"
+                case .textBased:     return "text-based stub"
+                case .framework:     return "framework"
+                case .object:        return "object file"
+                case .objectLibrary: return "object library"
                 }
             }
         }
@@ -144,7 +146,7 @@ open class LinkerSpec : CommandLineToolSpec, @unchecked Sendable {
     /// Custom entry point for constructing linker tasks.
     public func constructLinkerTasks(_ cbc: CommandBuildContext, _ delegate: any TaskGenerationDelegate, libraries: [LibrarySpecifier], usedTools: [CommandLineToolSpec: Set<FileTypeSpec>]) async {
         /// Delegate to the generic machinery.
-        await delegate.createTask(type: self, ruleInfo: defaultRuleInfo(cbc, delegate), commandLine: commandLineFromTemplate(cbc, delegate, optionContext: discoveredCommandLineToolSpecInfo(cbc.producer, cbc.scope, delegate)).map(\.asString), environment: environmentFromSpec(cbc, delegate), workingDirectory: cbc.producer.defaultWorkingDirectory, inputs: cbc.inputs.map({ $0.absolutePath }), outputs: [cbc.output], action: nil, execDescription: resolveExecutionDescription(cbc, delegate), enableSandboxing: enableSandboxing)
+        await delegate.createTask(type: self, ruleInfo: defaultRuleInfo(cbc, delegate), commandLine: commandLineFromTemplate(cbc, delegate, optionContext: discoveredCommandLineToolSpecInfo(cbc.producer, cbc.scope, delegate)).map(\.asString), environment: environmentFromSpec(cbc, delegate), workingDirectory: cbc.producer.defaultWorkingDirectory, inputs: cbc.inputs.map({ $0.absolutePath }), outputs: [cbc.output], action: createTaskAction(cbc, delegate), execDescription: resolveExecutionDescription(cbc, delegate), enableSandboxing: enableSandboxing)
     }
 }
 

Sources/SWBCore/SpecImplementations/RegisterSpecs.swift

@@ -58,6 +58,7 @@ public struct BuiltinSpecsExtension: SpecificationsExtension {
             LibtoolLinkerSpec.self,
             LipoToolSpec.self,
             MkdirToolSpec.self,
+            ObjectLibraryAssemblerSpec.self,
             PLUtilToolSpec.self,
             ProductPackagingToolSpec.self,
             ShellScriptToolSpec.self,

Sources/SWBCore/SpecImplementations/Tools/LinkerTools.swift

@@ -1228,6 +1228,9 @@ public final class LdLinkerSpec : GenericLinkerSpec, SpecIdentifierType, @unchec
             case .object:
                 // Object files are added to linker inputs in the sources task producer.
                 return ([], [])
+            case .objectLibrary:
+                let pathFlags = specifier.absolutePathFlagsForLd()
+                return (pathFlags, [specifier.path])
             }
         }.reduce(([], [])) { (lhs, rhs) in (lhs.args + rhs.args, lhs.inputs + rhs.inputs) }
     }
@@ -1464,6 +1467,9 @@ fileprivate extension LinkerSpec.LibrarySpecifier {
         case (.object, _):
             // Object files are added to linker inputs in the sources task producer.
             return []
+        case (.objectLibrary, _):
+            // Object libraries can't be found via search paths.
+            return []
         }
     }
 
@@ -1500,6 +1506,8 @@ fileprivate extension LinkerSpec.LibrarySpecifier {
         case (.object, _):
             // Object files are added to linker inputs in the sources task producer.
             return []
+        case (.objectLibrary, _):
+            return ["@\(path.join("args.resp").str)"]
         }
     }
 }
@@ -1601,6 +1609,10 @@ public final class LibtoolLinkerSpec : GenericLinkerSpec, SpecIdentifierType, @u
                 // Object files are added to linker inputs in the sources task producer and so end up in the link-file-list.
                 return []
 
+            case .objectLibrary:
+                inputPaths.append(specifier.path)
+                return ["@\(specifier.path.join("args.resp").str)"]
+
             case .framework:
                 // A static library can build against a framework, since the library in the framework could be a static library, which is valid, and we can't tell here whether it is or not.  So we leave it to libtool to do the right thing here.
                 // Also, we wouldn't want to emit an error here even if we could determine that it contained a dylib, since the target might be only using the framework to find headers.

Sources/SWBCore/SpecImplementations/Tools/ObjectLibraryAssembler.swift

@@ -0,0 +1,19 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2025 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
+//
+//===----------------------------------------------------------------------===//
+
+public final class ObjectLibraryAssemblerSpec : GenericLinkerSpec, SpecIdentifierType, @unchecked Sendable {
+    public static let identifier: String = "org.swift.linkers.object-library-assembler"
+
+    public override func createTaskAction(_ cbc: CommandBuildContext, _ delegate: any TaskGenerationDelegate) -> (any PlannedTaskAction)? {
+        return delegate.taskActionCreationDelegate.createObjectLibraryAssemblerTaskAction()
+    }
+}

Sources/SWBTaskConstruction/TaskProducers/BuildPhaseTaskProducers/SourcesTaskProducer.swift

@@ -687,6 +687,15 @@ final class SourcesTaskProducer: FilesBasedBuildPhaseTaskProducerBase, FilesBase
                     xcframeworkSourcePath: xcframeworkPath,
                     privacyFile: nil
                 )
+            } else if fileType.conformsTo(identifier: "compiled.object-library") {
+                return LinkerSpec.LibrarySpecifier(
+                    kind: .objectLibrary,
+                    path: absolutePath,
+                    mode: .normal,
+                    useSearchPaths: false,
+                    swiftModulePaths: swiftModulePaths,
+                    swiftModuleAdditionalLinkerArgResponseFilePaths: swiftModuleAdditionalLinkerArgResponseFilePaths,
+                )
             } else {
                 // FIXME: Error handling.
                 return nil
@@ -1624,20 +1633,30 @@ final class SourcesTaskProducer: FilesBasedBuildPhaseTaskProducerBase, FilesBase
     /// Compute the linker to use in the given scope.
     private func getLinkerToUse(_ scope: MacroEvaluationScope) -> LinkerSpec {
         let isStaticLib = scope.evaluate(BuiltinMacros.MACH_O_TYPE) == "staticlib"
+        let isObjectLibrary = context.productType?.conformsTo(identifier: "org.swift.product-type.library.object") == true
 
         // Return the custom linker, if specified.
-        var identifier = scope.evaluate(isStaticLib ? BuiltinMacros.LIBRARIAN : BuiltinMacros.LINKER)
-        if !identifier.isEmpty {
-            let spec = context.getSpec(identifier)
-            if let linker = spec as? LinkerSpec {
-                return linker
-            }
+        if !isObjectLibrary {
+            let identifier = scope.evaluate(isStaticLib ? BuiltinMacros.LIBRARIAN : BuiltinMacros.LINKER)
+            if !identifier.isEmpty {
+                let spec = context.getSpec(identifier)
+                if let linker = spec as? LinkerSpec {
+                    return linker
+                }
 
-            // FIXME: Emit a warning here.
+                // FIXME: Emit a warning here.
+            }
         }
 
         // Return the default linker.
-        identifier = isStaticLib ? LibtoolLinkerSpec.identifier : LdLinkerSpec.identifier
+        let identifier: String
+        if isObjectLibrary {
+            identifier = ObjectLibraryAssemblerSpec.identifier
+        } else if isStaticLib {
+            identifier = LibtoolLinkerSpec.identifier
+        } else {
+            identifier = LdLinkerSpec.identifier
+        }
         return context.getSpec(identifier) as! LinkerSpec
     }
 

Sources/SWBTaskConstruction/TaskProducers/TaskProducer.swift

@@ -1356,7 +1356,7 @@ extension TaskProducerContext: CommandProducer {
         let indexEnableBuildArena = scope.evaluate(BuiltinMacros.INDEX_ENABLE_BUILD_ARENA)
         let isBundleProductType = productType?.conformsTo(identifier: "com.apple.product-type.bundle") ?? false
         let isStaticLibrary = scope.evaluate(BuiltinMacros.MACH_O_TYPE) == "staticlib"
-        let isObject = scope.evaluate(BuiltinMacros.MACH_O_TYPE) == "mh_object"
+        let isObject = scope.evaluate(BuiltinMacros.MACH_O_TYPE) == "mh_object" && productType?.conformsTo(identifier: "org.swift.product-type.library.object") != true
         let result = (isBuild || isLocExport)
             && !indexEnableBuildArena
             && (isBundleProductType || isStaticLibrary || isObject)

Sources/SWBTaskExecution/BuildDescriptionManager.swift

@@ -891,6 +891,10 @@ extension BuildSystemTaskPlanningDelegate: TaskActionCreationDelegate {
     func createProcessSDKImportsTaskAction() -> any PlannedTaskAction {
         return ProcessSDKImportsTaskAction()
     }
+
+    func createObjectLibraryAssemblerTaskAction() -> any PlannedTaskAction {
+        return ObjectLibraryAssemblerTaskAction()
+    }
 }
 
 fileprivate extension BuildDescription {

Sources/SWBTaskExecution/BuiltinTaskActionsExtension.swift

@@ -51,7 +51,8 @@ public struct BuiltinTaskActionsExtension: TaskActionExtension {
             36: ConstructStubExecutorInputFileListTaskAction.self,
             37: ConcatenateTaskAction.self,
             38: GenericCachingTaskAction.self,
-            39: ProcessSDKImportsTaskAction.self
+            39: ProcessSDKImportsTaskAction.self,
+            42: ObjectLibraryAssemblerTaskAction.self
         ]
     }
 }