Serialization: Change InputFile to use FileEntryRef and add getVirtualFileRef, NFC

Change the `InputFile` class to store `Optional<FileEntryRef>` instead
of `FileEntry*`. This paged in a few API changes:

- Added `FileManager::getVirtualFileRef`, and converted `getVirtualFile`
  to a wrapper of it.
- Updated `SourceManager::bypassFileContentsOverride` to take
  `FileEntryRef` and return `Optional<FileEntryRef>`
  (`ASTReader::getInputFile` is the only caller).

Differential Revision: https://reviews.llvm.org/D90053

1 files changed, 7 insertions, 9 deletions

diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index dde4471..b71b2be 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -698,19 +698,17 @@ void SourceManager::overrideFileContents(const FileEntry *SourceFile,
   getOverriddenFilesInfo().OverriddenFiles[SourceFile] = NewFile;
 }
 
-const FileEntry *
-SourceManager::bypassFileContentsOverride(const FileEntry &File) {
-  assert(isFileOverridden(&File));
-  llvm::Optional<FileEntryRef> BypassFile =
-      FileMgr.getBypassFile(File.getLastRef());
+Optional<FileEntryRef>
+SourceManager::bypassFileContentsOverride(FileEntryRef File) {
+  assert(isFileOverridden(&File.getFileEntry()));
+  llvm::Optional<FileEntryRef> BypassFile = FileMgr.getBypassFile(File);
 
   // If the file can't be found in the FS, give up.
   if (!BypassFile)
-    return nullptr;
+    return None;
 
-  const FileEntry *FE = &BypassFile->getFileEntry();
-  (void)getOrCreateContentCache(FE);
-  return FE;
+  (void)getOrCreateContentCache(&BypassFile->getFileEntry());
+  return BypassFile;
 }
 
 void SourceManager::setFileIsTransient(const FileEntry *File) {