[Dependency Scanning] Add support for Swift Overlay dependencies as a…

… separate dependency details field

Instead of assuming such dependencies are contained in the 'directDependencies' field of the module info, support querying them from a details of a textual module.

Sources/CSwiftScan/include/swiftscan_header.h

@@ -122,6 +122,8 @@ typedef struct {
   (*swiftscan_swift_textual_detail_get_context_hash)(swiftscan_module_details_t);
   bool
   (*swiftscan_swift_textual_detail_get_is_framework)(swiftscan_module_details_t);
+  swiftscan_string_set_t *
+  (*swiftscan_swift_textual_detail_get_swift_overlay_dependencies)(swiftscan_module_details_t);
 
   //=== Swift Binary Module Details query APIs ------------------------------===//
   swiftscan_string_ref_t

Sources/SwiftDriver/ExplicitModuleBuilds/ExplicitDependencyBuildPlanner.swift

@@ -124,7 +124,6 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
     }
     for moduleId in swiftDependencies {
       let moduleInfo = try dependencyGraph.moduleInfo(of: moduleId)
-      let pcmArgs = try dependencyGraph.swiftModulePCMArgs(of: moduleId)
       var inputs: [TypedVirtualPath] = []
       let outputs: [TypedVirtualPath] = [
         TypedVirtualPath(file: moduleInfo.modulePath.path, type: .swiftModule)

Sources/SwiftDriver/ExplicitModuleBuilds/InterModuleDependencies/CommonDependencyOperations.swift

@@ -75,9 +75,22 @@ extension InterModuleDependencyGraph {
       }
     // Traverse the set of modules in reverse topological order, assimilating transitive closures
     for moduleId in topologicalIdList.reversed() {
-      for dependencyId in try moduleInfo(of: moduleId).directDependencies! {
+      let moduleInfo = try moduleInfo(of: moduleId)
+      for dependencyId in moduleInfo.directDependencies! {
         transitiveClosureMap[moduleId]!.formUnion(transitiveClosureMap[dependencyId]!)
       }
+      // For Swift dependencies, their corresponding Swift Overlay dependencies
+      // and bridging header dependencies are equivalent to direct dependencies.
+      if case .swift(let swiftModuleDetails) = moduleInfo.details {
+        let swiftOverlayDependencies = swiftModuleDetails.swiftOverlayDependencies ?? []
+        for dependencyId in swiftOverlayDependencies {
+          transitiveClosureMap[moduleId]!.formUnion(transitiveClosureMap[dependencyId]!)
+        }
+        let bridgingHeaderDependencies = swiftModuleDetails.bridgingHeaderDependencies ?? []
+        for dependencyId in bridgingHeaderDependencies {
+          transitiveClosureMap[moduleId]!.formUnion(transitiveClosureMap[dependencyId]!)
+        }
+      }
     }
     // For ease of use down-the-line, remove the node's self from its set of reachable nodes
     for (key, _) in transitiveClosureMap {

Sources/SwiftDriver/ExplicitModuleBuilds/InterModuleDependencies/InterModuleDependencyGraph.swift

@@ -79,7 +79,9 @@ extension ModuleDependencyId: Codable {
 /// Bridging header
 public struct BridgingHeader: Codable {
   var path: TextualVirtualPath
+  /// The source files referenced by the bridging header.
   var sourceFiles: [TextualVirtualPath]
+  /// Modules that the bridging header specifically depends on
   var moduleDependencies: [String]
 }
 
@@ -92,13 +94,16 @@ public struct SwiftModuleDetails: Codable {
   public var compiledModuleCandidates: [TextualVirtualPath]?
 
   /// The bridging header, if any.
-  public var bridgingHeaderPath: TextualVirtualPath?
-
-  /// The source files referenced by the bridging header.
-  public var bridgingSourceFiles: [TextualVirtualPath]? = []
-
-  /// Modules that the bridging header specifically depends on
-  public var bridgingHeaderDependencies: [ModuleDependencyId]? = []
+  public var bridgingHeader: BridgingHeader?
+  public var bridgingHeaderPath: TextualVirtualPath? {
+    bridgingHeader?.path
+  }
+  public var bridgingSourceFiles: [TextualVirtualPath]? {
+    bridgingHeader?.sourceFiles
+  }
+  public var bridgingHeaderDependencies: [ModuleDependencyId]? {
+    bridgingHeader?.moduleDependencies.map { .clang($0) }
+  }
 
   /// Options to the compile command
   public var commandLine: [String]? = []
@@ -115,6 +120,9 @@ public struct SwiftModuleDetails: Codable {
 
   /// A flag to indicate whether or not this module is a framework.
   public var isFramework: Bool?
+
+  /// A set of Swift Overlays of Clang Module Dependencies
+  var swiftOverlayDependencies: [ModuleDependencyId]?
 }
 
 /// Details specific to Swift placeholder dependencies.

Sources/SwiftDriver/SwiftScan/DependencyGraphBuilder.swift

@@ -123,7 +123,8 @@ private extension SwiftScan {
     guard let moduleDetailsRef = api.swiftscan_module_info_get_details(moduleInfoRef) else {
       throw DependencyScanningError.missingField("modules[\(moduleId)].details")
     }
-    let details = try constructModuleDetails(from: moduleDetailsRef)
+    let details = try constructModuleDetails(from: moduleDetailsRef,
+                                             moduleAliases: moduleAliases)
 
     return (moduleId, ModuleInfo(modulePath: modulePath, sourceFiles: sourceFiles,
                                  directDependencies: directDependencies,
@@ -133,12 +134,14 @@ private extension SwiftScan {
   /// From a reference to a binary-format module info details object info returned by libSwiftScan,
   /// construct an instance of an `ModuleInfo`.Details as used by the driver.
   /// The object returned by libSwiftScan is a union so ensure to execute dependency-specific queries.
-  func constructModuleDetails(from moduleDetailsRef: swiftscan_module_details_t)
+  func constructModuleDetails(from moduleDetailsRef: swiftscan_module_details_t,
+                              moduleAliases: [String: String]?)
   throws -> ModuleInfo.Details {
     let moduleKind = api.swiftscan_module_detail_get_kind(moduleDetailsRef)
     switch moduleKind {
       case SWIFTSCAN_DEPENDENCY_INFO_SWIFT_TEXTUAL:
-        return .swift(try constructSwiftTextualModuleDetails(from: moduleDetailsRef))
+        return .swift(try constructSwiftTextualModuleDetails(from: moduleDetailsRef,
+                                                             moduleAliases: moduleAliases))
       case SWIFTSCAN_DEPENDENCY_INFO_SWIFT_BINARY:
         return .swiftPrebuiltExternal(try constructSwiftBinaryModuleDetails(from: moduleDetailsRef))
       case SWIFTSCAN_DEPENDENCY_INFO_SWIFT_PLACEHOLDER:
@@ -151,7 +154,8 @@ private extension SwiftScan {
   }
 
   /// Construct a `SwiftModuleDetails` from a `swiftscan_module_details_t` reference
-  func constructSwiftTextualModuleDetails(from moduleDetailsRef: swiftscan_module_details_t)
+  func constructSwiftTextualModuleDetails(from moduleDetailsRef: swiftscan_module_details_t,
+                                          moduleAliases: [String: String]?)
   throws -> SwiftModuleDetails {
     let moduleInterfacePath =
       try getOptionalPathDetail(from: moduleDetailsRef,
@@ -168,6 +172,15 @@ private extension SwiftScan {
     let bridgingHeaderDependencies =
       try getOptionalStringArrayDetail(from: moduleDetailsRef,
                                        using: api.swiftscan_swift_textual_detail_get_bridging_module_dependencies)
+    let bridgingHeader: BridgingHeader?
+    if let resolvedBridgingHeaderPath = bridgingHeaderPath {
+      bridgingHeader = BridgingHeader(path: resolvedBridgingHeaderPath,
+                                      sourceFiles: bridgingSourceFiles ?? [],
+                                      moduleDependencies: bridgingHeaderDependencies ?? [])
+    } else {
+      bridgingHeader = nil
+    }
+
     let commandLine =
       try getOptionalStringArrayDetail(from: moduleDetailsRef,
                                        using: api.swiftscan_swift_textual_detail_get_command_line)
@@ -180,15 +193,25 @@ private extension SwiftScan {
                           using: api.swiftscan_swift_textual_detail_get_context_hash)
     let isFramework = api.swiftscan_swift_textual_detail_get_is_framework(moduleDetailsRef)
 
+    // Decode all dependencies of this module
+    let swiftOverlayDependencies: [ModuleDependencyId]?
+    if supportsSeparateSwiftOverlayDependencies(),
+       let encodedOverlayDepsRef = api.swiftscan_swift_textual_detail_get_swift_overlay_dependencies(moduleDetailsRef) {
+      let encodedOverlayDependencies = try toSwiftStringArray(encodedOverlayDepsRef.pointee)
+      swiftOverlayDependencies =
+        try encodedOverlayDependencies.map { try decodeModuleNameAndKind(from: $0, moduleAliases: moduleAliases) }
+    } else {
+      swiftOverlayDependencies = nil
+    }
+
     return SwiftModuleDetails(moduleInterfacePath: moduleInterfacePath,
                               compiledModuleCandidates: compiledModuleCandidates,
-                              bridgingHeaderPath: bridgingHeaderPath,
-                              bridgingSourceFiles: bridgingSourceFiles,
-                              bridgingHeaderDependencies: bridgingHeaderDependencies?.map { .clang($0) },
+                              bridgingHeader: bridgingHeader,
                               commandLine: commandLine,
                               contextHash: contextHash,
                               extraPcmArgs: extraPcmArgs,
-                              isFramework: isFramework)
+                              isFramework: isFramework,
+                              swiftOverlayDependencies: swiftOverlayDependencies)
   }
 
   /// Construct a `SwiftPrebuiltExternalModuleDetails` from a `swiftscan_module_details_t` reference

Sources/SwiftDriver/SwiftScan/SwiftScan.swift

@@ -263,6 +263,10 @@ internal extension swiftscan_diagnostic_severity_t {
   func resetScannerCache() {
     api.swiftscan_scanner_cache_reset(scanner)
   }
+
+  @_spi(Testing) public func supportsSeparateSwiftOverlayDependencies() -> Bool {
+    return api.swiftscan_swift_textual_detail_get_swift_overlay_dependencies != nil
+  }
 
   @_spi(Testing) public func supportsScannerDiagnostics() -> Bool {
     return api.swiftscan_scanner_diagnostics_query != nil &&
@@ -419,6 +423,10 @@ private extension swiftscan_functions_t {
     self.swiftscan_swift_binary_detail_get_is_framework =
       try loadOptional("swiftscan_swift_binary_detail_get_is_framework")
 
+    // Swift Overlay Dependencies
+    self.swiftscan_swift_textual_detail_get_swift_overlay_dependencies =
+      try loadOptional("swiftscan_swift_textual_detail_get_swift_overlay_dependencies")
+
     // MARK: Required Methods
     func loadRequired<T>(_ symbol: String) throws -> T {
       guard let sym: T = Loader.lookup(symbol: symbol, in: swiftscan) else {