   }
 }
 extension OutputFileMap {
-  fileprivate func getDependencySource(
+  fileprivate func dependencySource(
     for sourceFile: TypedVirtualPath,
     diagnosticEngine: DiagnosticsEngine
   ) -> DependencySource? {

  ) -> TransitivelyInvalidatedInputSet? {
    var invalidatedInputs = TransitivelyInvalidatedInputSet()
    for invalidatedSwiftDeps in collectSwiftDepsUsingInvalidated(nodes: directlyInvalidatedNodes) {
      guard let invalidatedInput = getNeededInput(for: invalidatedSwiftDeps)
      else {
        return nil
      }
      invalidatedInputs.insert(invalidatedInput)

    let diags = info.diagnosticEngine
    var allFound = true
    for input in info.inputFiles {
      if let source = ofm.dependencySource(for: input, diagnosticEngine: diags) {
        inputDependencySourceMap.addEntry(input, source, for: purpose)
      } else {
        // Don't break in order to report all failures.
        allFound = false
      }
