When an import statement fails to find a module in the module cache,
but there is a corresponding umbrella header in a framework, build the
module on-the-fly so it can be immediately loaded at the import
statement. This is very much proof-of-concept code, with details to be
fleshed out over time.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@139558 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/FileManager.cpp b/lib/Basic/FileManager.cpp
index 4ac8e4d..adc9705 100644
--- a/lib/Basic/FileManager.cpp
+++ b/lib/Basic/FileManager.cpp
@@ -380,6 +380,10 @@
   return &UFE;
 }
 
+void FileManager::forgetFile(StringRef Filename) {
+  SeenFileEntries.erase(Filename);
+}
+
 const FileEntry *
 FileManager::getVirtualFile(StringRef Filename, off_t Size,
                             time_t ModificationTime) {