[clang][deps] Avoid leaking modulemap paths across unrelated imports

Use a FileEntryRef when retrieving modulemap paths in the scanner so
that we use a path compatible with the original module import, rather
than a FileEntry which can allow unrelated modules to leak paths into
how we build a module due to FileManager mutating the path.

Note: the current change prevents an "unrelated" path, but does not
change how VFS mapped paths are handled (which would be calling
getNameAsRequested) nor canonicalize the path.

Differential Revision: https://reviews.llvm.org/D137989

1 files changed, 4 insertions, 5 deletions

diff --git a/clang/lib/Frontend/FrontendAction.cpp b/clang/lib/Frontend/FrontendAction.cpp
index 45f04ea..76ef0cb 100644
--- a/clang/lib/Frontend/FrontendAction.cpp
+++ b/clang/lib/Frontend/FrontendAction.cpp
@@ -638,11 +638,10 @@ bool FrontendAction::BeginSourceFile(CompilerInstance &CI,
         if (&MF != &PrimaryModule)
           CI.getFrontendOpts().ModuleFiles.push_back(MF.FileName);
 
-      ASTReader->visitTopLevelModuleMaps(
-          PrimaryModule, [&](const FileEntry *FE) {
-            CI.getFrontendOpts().ModuleMapFiles.push_back(
-                std::string(FE->getName()));
-          });
+      ASTReader->visitTopLevelModuleMaps(PrimaryModule, [&](FileEntryRef FE) {
+        CI.getFrontendOpts().ModuleMapFiles.push_back(
+            std::string(FE.getName()));
+      });
     }
 
     // Set up the input file for replay purposes.