1 files changed, 15 insertions, 2 deletions
diff --git a/contrib/llvm/tools/clang/lib/Lex/HeaderSearch.cpp b/contrib/llvm/tools/clang/lib/Lex/HeaderSearch.cpp
index f5b7c59e446f..9084bc352f76 100644
--- a/contrib/llvm/tools/clang/lib/Lex/HeaderSearch.cpp
+++ b/contrib/llvm/tools/clang/lib/Lex/HeaderSearch.cpp
@@ -1326,14 +1326,27 @@ static const FileEntry *getPrivateModuleMap(const FileEntry *File,
 }
 
 bool HeaderSearch::loadModuleMapFile(const FileEntry *File, bool IsSystem,
-                                     FileID ID, unsigned *Offset) {
+                                     FileID ID, unsigned *Offset,
+                                     StringRef OriginalModuleMapFile) {
   // Find the directory for the module. For frameworks, that may require going
   // up from the 'Modules' directory.
   const DirectoryEntry *Dir = nullptr;
   if (getHeaderSearchOpts().ModuleMapFileHomeIsCwd)
     Dir = FileMgr.getDirectory(".");
   else {
-    Dir = File->getDir();
+    if (!OriginalModuleMapFile.empty()) {
+      // We're building a preprocessed module map. Find or invent the directory
+      // that it originally occupied.
+      Dir = FileMgr.getDirectory(
+          llvm::sys::path::parent_path(OriginalModuleMapFile));
+      if (!Dir) {
+        auto *FakeFile = FileMgr.getVirtualFile(OriginalModuleMapFile, 0, 0);
+        Dir = FakeFile->getDir();
+      }
+    } else {
+      Dir = File->getDir();
+    }
+
     StringRef DirName(Dir->getName());
     if (llvm::sys::path::filename(DirName) == "Modules") {
       DirName = llvm::sys::path::parent_path(DirName);