Merge pull request #34218 from CodaFi/pseudo-lithis

Patch Out Use-Of-Stack-After-Free In Cross Module Dependencies

Author: eeckstein

lib/Driver/FineGrainedDependencyDriverGraph.cpp

@@ -752,6 +752,11 @@ StringRef ModuleDepGraph::getProvidingFilename(
     const Optional<std::string> swiftDeps) const {
   if (!swiftDeps)
     return "<unknown";
+  auto ext = llvm::sys::path::extension(*swiftDeps);
+  if (file_types::lookupTypeForExtension(ext) ==
+      file_types::TY_SwiftModuleFile) {
+    return *swiftDeps;
+  }
   const StringRef inputName =
       llvm::sys::path::filename(getJob(swiftDeps)->getFirstSwiftPrimaryInput());
   // FineGrainedDependencyGraphTests work with simulated jobs with empty