[Explicit Module Builds] Add API for external dependencies for Explicit Package Builds

Author: artemcm

Sources/SwiftDriver/Driver/Driver.swift

@@ -193,6 +193,11 @@ public struct Driver {
   /// as explicit by the various compilation jobs.
   @_spi(Testing) public var explicitModuleBuildHandler: ExplicitModuleBuildHandler? = nil
 
+  /// A collection describing external dependencies for the current main module that may be invisible to
+  /// the driver itself, but visible to its clients (e.g. build systems like SwiftPM). Along with the external dependenceis'
+  /// module dependency graphs.
+  internal var externalDependencyArtifactMap: ExternalDependencyArtifactMap? = nil
+
   /// Handler for emitting diagnostics to stderr.
   public static let stderrDiagnosticsHandler: DiagnosticsEngine.DiagnosticsHandler = { diagnostic in
     let stream = stderrStream
@@ -226,24 +231,30 @@ public struct Driver {
   /// - Parameter diagnosticsHandler: A callback executed when a diagnostic is
   ///   emitted. The default argument prints diagnostics to stderr.
   /// - Parameter executor: Used by the driver to execute jobs. The default argument
-  /// is present to streamline testing, it shouldn't be used in production.
+  ///   is present to streamline testing, it shouldn't be used in production.
+  /// - Parameter externalModuleDependencies: A collection of external modules that the main module
+  ///   of the current compilation depends on. Explicit Module Build use only.
   public init(
     args: [String],
     env: [String: String] = ProcessEnv.vars,
     diagnosticsEngine: DiagnosticsEngine = DiagnosticsEngine(handlers: [Driver.stderrDiagnosticsHandler]),
     fileSystem: FileSystem = localFileSystem,
-    executor: DriverExecutor
+    executor: DriverExecutor,
+    externalModuleDependencies: ExternalDependencyArtifactMap? = nil
   ) throws {
     self.env = env
     self.fileSystem = fileSystem
 
     self.diagnosticEngine = diagnosticsEngine
     self.executor = executor
 
+    self.externalDependencyArtifactMap = externalModuleDependencies
+
     if case .subcommand = try Self.invocationRunMode(forArgs: args).mode {
       throw Error.subcommandPassedToDriver
     }
 
+
     var args = try Self.expandResponseFiles(args, fileSystem: fileSystem, diagnosticsEngine: self.diagnosticEngine)
 
     self.driverKind = try Self.determineDriverKind(args: &args)

Sources/SwiftDriver/Explicit Module Builds/ExplicitModuleBuildHandler.swift

@@ -13,9 +13,13 @@ import TSCBasic
 import TSCUtility
 import Foundation
 
+public typealias ExternalDependencyArtifactMap =
+    [ModuleDependencyId: (AbsolutePath, InterModuleDependencyGraph)]
+
 /// In Explicit Module Build mode, this handler is responsible for generating and providing
 /// build jobs for all module dependencies and providing compile command options
 /// that specify said explicit module dependencies.
+
 @_spi(Testing) public struct ExplicitModuleBuildHandler {
   /// The module dependency graph.
   public var dependencyGraph: InterModuleDependencyGraph
@@ -30,6 +34,9 @@ import Foundation
   /// The toolchain to be used for frontend job generation.
   private let toolchain: Toolchain
 
+  /// A collection of external dependency modules, and their binary module file paths and dependency graph.
+  private let externalDependencyArtifactMap: ExternalDependencyArtifactMap
+
   /// The file system which we should interact with.
   /// FIXME: Our end goal is to not have any direct filesystem manipulation in here, but  that's dependent on getting the
   /// dependency scanner/dependency job generation  moved into a Job.
@@ -42,9 +49,11 @@ import Foundation
   private let temporaryDirectory: AbsolutePath
 
   public init(dependencyGraph: InterModuleDependencyGraph, toolchain: Toolchain,
-              fileSystem: FileSystem) throws {
+              fileSystem: FileSystem,
+              externalDependencyArtifactMap: ExternalDependencyArtifactMap) throws {
     self.dependencyGraph = dependencyGraph
     self.toolchain = toolchain
+    self.externalDependencyArtifactMap = externalDependencyArtifactMap
     self.fileSystem = fileSystem
     self.temporaryDirectory = try determineTempDirectory()
   }
@@ -457,4 +466,10 @@ private extension InterModuleDependencyGraph {
   }
 }
 
-
+// To keep the ExplicitModuleBuildHandler an implementation detail, provide an API
+// to access the dependency graph
+extension Driver {
+  public var interModuleDependencyGraph: InterModuleDependencyGraph? {
+    return explicitModuleBuildHandler?.dependencyGraph
+  }
+}

Sources/SwiftDriver/Explicit Module Builds/InterModuleDependencyGraph.swift

@@ -12,7 +12,7 @@
 import Foundation
 
 
-@_spi(Testing) public enum ModuleDependencyId: Hashable {
+public enum ModuleDependencyId: Hashable {
   case swift(String)
   case clang(String)
 
@@ -53,7 +53,7 @@ extension ModuleDependencyId: Codable {
 }
 
 /// Details specific to Swift modules.
-@_spi(Testing) public struct SwiftModuleDetails: Codable {
+public struct SwiftModuleDetails: Codable {
   /// The module interface from which this module was built, if any.
   public var moduleInterfacePath: String?
 
@@ -79,7 +79,7 @@ extension ModuleDependencyId: Codable {
 }
 
 /// Details specific to Clang modules.
-@_spi(Testing) public struct ClangModuleDetails: Codable {
+public struct ClangModuleDetails: Codable {
   /// The path to the module map used to build this module.
   public var moduleMapPath: String
 
@@ -90,7 +90,7 @@ extension ModuleDependencyId: Codable {
   public var commandLine: [String]? = []
 }
 
-@_spi(Testing) public struct ModuleInfo: Codable {
+public struct ModuleInfo: Codable {
   /// The path for the module.
   public var modulePath: String
 
@@ -144,7 +144,7 @@ extension ModuleInfo.Details: Codable {
 
 /// Describes the complete set of dependencies for a Swift module, including
 /// all of the Swift and C modules and source files it depends on.
-@_spi(Testing) public struct InterModuleDependencyGraph: Codable {
+public struct InterModuleDependencyGraph: Codable {
   /// The name of the main module.
   public var mainModuleName: String
 

Sources/SwiftDriver/Jobs/Planning.swift

@@ -230,9 +230,11 @@ extension Driver {
                                 forceResponseFiles: forceResponseFiles,
                                 recordedInputModificationDates: recordedInputModificationDates)
 
-    explicitModuleBuildHandler = try ExplicitModuleBuildHandler(dependencyGraph: dependencyGraph,
-                                                                toolchain: toolchain,
-                                                                fileSystem: fileSystem)
+    explicitModuleBuildHandler =
+        try ExplicitModuleBuildHandler(dependencyGraph: dependencyGraph,
+                                       toolchain: toolchain,
+                                       fileSystem: fileSystem,
+                                       externalDependencyArtifactMap: externalDependencyArtifactMap ?? [:])
     return try explicitModuleBuildHandler!.generateExplicitModuleDependenciesBuildJobs()
   }
 

Tests/SwiftDriverTests/ExplicitModuleBuildTests.swift

@@ -133,7 +133,8 @@ final class ExplicitModuleBuildTests: XCTestCase {
               from: ModuleDependenciesInputs.fastDependencyScannerOutput.data(using: .utf8)!)
       driver.explicitModuleBuildHandler = try ExplicitModuleBuildHandler(dependencyGraph: moduleDependencyGraph,
                                                                          toolchain: driver.toolchain,
-                                                                         fileSystem: localFileSystem)
+                                                                         fileSystem: localFileSystem,
+                                                                         externalDependencyArtifactMap: [:])
       let modulePrebuildJobs =
         try driver.explicitModuleBuildHandler!.generateExplicitModuleDependenciesBuildJobs()
       XCTAssertEqual(modulePrebuildJobs.count, 4)