Introduce FileEntryRef and use it when handling includes to report correct dependencies

when the FileManager is reused across invocations

This commit introduces a parallel API to FileManager's getFile: getFileEntryRef, which returns
a reference to the FileEntry, and the name that was used to access the file. In the case of
a VFS with 'use-external-names', the FileEntyRef contains the external name of the file,
not the filename that was used to access it.

The new API is adopted only in the HeaderSearch and Preprocessor for include file lookup, so that the
accessed path can be propagated to SourceManager's FileInfo. SourceManager's FileInfo now can report this accessed path, using
the new getName method. This API is then adopted in the dependency collector, which now correctly reports dependencies when a file
is included both using a symlink and a real path in the case when the FileManager is reused across multiple Preprocessor invocations.

Note that this patch does not fix all dependency collector issues, as the same problem is still present in other cases when dependencies
are obtained using FileSkipped, InclusionDirective, and HasInclude. This will be fixed in follow-up commits.

Differential Revision: https://reviews.llvm.org/D65907

llvm-svn: 369680

6 files changed, 280 insertions, 252 deletions

diff --git a/clang/lib/Lex/HeaderMap.cpp b/clang/lib/Lex/HeaderMap.cpp
index 7a46fafafa0..1c7fb1a4764 100644
--- a/clang/lib/Lex/HeaderMap.cpp
+++ b/clang/lib/Lex/HeaderMap.cpp
@@ -196,17 +196,17 @@ LLVM_DUMP_METHOD void HeaderMapImpl::dump() const {
 
 /// LookupFile - Check to see if the specified relative filename is located in
 /// this HeaderMap.  If so, open it and return its FileEntry.
-const FileEntry *HeaderMap::LookupFile(
-    StringRef Filename, FileManager &FM) const {
+Optional<FileEntryRef> HeaderMap::LookupFile(StringRef Filename,
+                                             FileManager &FM) const {
 
   SmallString<1024> Path;
   StringRef Dest = HeaderMapImpl::lookupFilename(Filename, Path);
   if (Dest.empty())
-    return nullptr;
+    return None;
 
-  if (auto File = FM.getFile(Dest))
+  if (auto File = FM.getFileRef(Dest))
     return *File;
-  return nullptr;
+  return None;
 }
 
 StringRef HeaderMapImpl::lookupFilename(StringRef Filename,
diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 7bc953ba1aa..84af65c30d5 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -304,14 +304,13 @@ StringRef DirectoryLookup::getName() const {
   return getHeaderMap()->getFileName();
 }
 
-const FileEntry *HeaderSearch::getFileAndSuggestModule(
+Optional<FileEntryRef> HeaderSearch::getFileAndSuggestModule(
     StringRef FileName, SourceLocation IncludeLoc, const DirectoryEntry *Dir,
     bool IsSystemHeaderDir, Module *RequestingModule,
     ModuleMap::KnownHeader *SuggestedModule) {
   // If we have a module map that might map this header, load it and
   // check whether we'll have a suggestion for a module.
-  llvm::ErrorOr<const FileEntry *> File =
-      getFileMgr().getFile(FileName, /*OpenFile=*/true);
+  auto File = getFileMgr().getFileRef(FileName, /*OpenFile=*/true);
   if (!File) {
     // For rare, surprising errors (e.g. "out of file handles"), diag the EC
     // message.
@@ -322,32 +321,26 @@ const FileEntry *HeaderSearch::getFileAndSuggestModule(
       Diags.Report(IncludeLoc, diag::err_cannot_open_file)
           << FileName << EC.message();
     }
-    return nullptr;
+    return None;
   }
 
   // If there is a module that corresponds to this header, suggest it.
-  if (!findUsableModuleForHeader(*File, Dir ? Dir : (*File)->getDir(),
-                                 RequestingModule, SuggestedModule,
-                                 IsSystemHeaderDir))
-    return nullptr;
+  if (!findUsableModuleForHeader(
+          &File->getFileEntry(), Dir ? Dir : File->getFileEntry().getDir(),
+          RequestingModule, SuggestedModule, IsSystemHeaderDir))
+    return None;
 
   return *File;
 }
 
 /// LookupFile - Lookup the specified file in this search path, returning it
 /// if it exists or returning null if not.
-const FileEntry *DirectoryLookup::LookupFile(
-    StringRef &Filename,
-    HeaderSearch &HS,
-    SourceLocation IncludeLoc,
-    SmallVectorImpl<char> *SearchPath,
-    SmallVectorImpl<char> *RelativePath,
-    Module *RequestingModule,
-    ModuleMap::KnownHeader *SuggestedModule,
-    bool &InUserSpecifiedSystemFramework,
-    bool &IsFrameworkFound,
-    bool &HasBeenMapped,
-    SmallVectorImpl<char> &MappedName) const {
+Optional<FileEntryRef> DirectoryLookup::LookupFile(
+    StringRef &Filename, HeaderSearch &HS, SourceLocation IncludeLoc,
+    SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
+    Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule,
+    bool &InUserSpecifiedSystemFramework, bool &IsFrameworkFound,
+    bool &HasBeenMapped, SmallVectorImpl<char> &MappedName) const {
   InUserSpecifiedSystemFramework = false;
   HasBeenMapped = false;
 
@@ -381,9 +374,19 @@ const FileEntry *DirectoryLookup::LookupFile(
   SmallString<1024> Path;
   StringRef Dest = HM->lookupFilename(Filename, Path);
   if (Dest.empty())
-    return nullptr;
+    return None;
 
-  const FileEntry *Result;
+  auto FixupSearchPath = [&]() {
+    if (SearchPath) {
+      StringRef SearchPathRef(getName());
+      SearchPath->clear();
+      SearchPath->append(SearchPathRef.begin(), SearchPathRef.end());
+    }
+    if (RelativePath) {
+      RelativePath->clear();
+      RelativePath->append(Filename.begin(), Filename.end());
+    }
+  };
 
   // Check if the headermap maps the filename to a framework include
   // ("Foo.h" -> "Foo/Foo.h"), in which case continue header lookup using the
@@ -393,25 +396,17 @@ const FileEntry *DirectoryLookup::LookupFile(
     MappedName.append(Dest.begin(), Dest.end());
     Filename = StringRef(MappedName.begin(), MappedName.size());
     HasBeenMapped = true;
-    Result = HM->LookupFile(Filename, HS.getFileMgr());
-  } else if (auto Res = HS.getFileMgr().getFile(Dest)) {
-    Result = *Res;
-  } else {
-    Result = nullptr;
-  }
-
-  if (Result) {
-    if (SearchPath) {
-      StringRef SearchPathRef(getName());
-      SearchPath->clear();
-      SearchPath->append(SearchPathRef.begin(), SearchPathRef.end());
-    }
-    if (RelativePath) {
-      RelativePath->clear();
-      RelativePath->append(Filename.begin(), Filename.end());
+    Optional<FileEntryRef> Result = HM->LookupFile(Filename, HS.getFileMgr());
+    if (Result) {
+      FixupSearchPath();
+      return *Result;
     }
+  } else if (auto Res = HS.getFileMgr().getFileRef(Dest)) {
+    FixupSearchPath();
+    return *Res;
   }
-  return Result;
+
+  return None;
 }
 
 /// Given a framework directory, find the top-most framework directory.
@@ -476,7 +471,7 @@ static bool needModuleLookup(Module *RequestingModule,
 
 /// DoFrameworkLookup - Do a lookup of the specified file in the current
 /// DirectoryLookup, which is a framework directory.
-const FileEntry *DirectoryLookup::DoFrameworkLookup(
+Optional<FileEntryRef> DirectoryLookup::DoFrameworkLookup(
     StringRef Filename, HeaderSearch &HS, SmallVectorImpl<char> *SearchPath,
     SmallVectorImpl<char> *RelativePath, Module *RequestingModule,
     ModuleMap::KnownHeader *SuggestedModule,
@@ -485,7 +480,8 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   // Framework names must have a '/' in the filename.
   size_t SlashPos = Filename.find('/');
-  if (SlashPos == StringRef::npos) return nullptr;
+  if (SlashPos == StringRef::npos)
+    return None;
 
   // Find out if this is the home for the specified framework, by checking
   // HeaderSearch.  Possible answers are yes/no and unknown.
@@ -494,7 +490,7 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   // If it is known and in some other directory, fail.
   if (CacheEntry.Directory && CacheEntry.Directory != getFrameworkDir())
-    return nullptr;
+    return None;
 
   // Otherwise, construct the path to this framework dir.
 
@@ -517,7 +513,8 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
     // If the framework dir doesn't exist, we fail.
     auto Dir = FileMgr.getDirectory(FrameworkName);
-    if (!Dir) return nullptr;
+    if (!Dir)
+      return None;
 
     // Otherwise, if it does, remember that this is the right direntry for this
     // framework.
@@ -556,11 +553,10 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
 
   FrameworkName.append(Filename.begin()+SlashPos+1, Filename.end());
 
-  const FileEntry *FE = nullptr;
-  if (auto File = FileMgr.getFile(FrameworkName, /*OpenFile=*/!SuggestedModule))
-    FE = *File;
+  llvm::ErrorOr<FileEntryRef> File =
+      FileMgr.getFileRef(FrameworkName, /*OpenFile=*/!SuggestedModule);
 
-  if (!FE) {
+  if (!File) {
     // Check "/System/Library/Frameworks/Cocoa.framework/PrivateHeaders/file.h"
     const char *Private = "Private";
     FrameworkName.insert(FrameworkName.begin()+OrigSize, Private,
@@ -569,15 +565,13 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
       SearchPath->insert(SearchPath->begin()+OrigSize, Private,
                          Private+strlen(Private));
 
-    if (auto File = FileMgr.getFile(FrameworkName, 
-                                    /*OpenFile=*/!SuggestedModule))
-      FE = *File;
+    File = FileMgr.getFileRef(FrameworkName, /*OpenFile=*/!SuggestedModule);
   }
 
   // If we found the header and are allowed to suggest a module, do so now.
-  if (FE && needModuleLookup(RequestingModule, SuggestedModule)) {
+  if (File && needModuleLookup(RequestingModule, SuggestedModule)) {
     // Find the framework in which this header occurs.
-    StringRef FrameworkPath = FE->getDir()->getName();
+    StringRef FrameworkPath = File->getFileEntry().getDir()->getName();
     bool FoundFramework = false;
     do {
       // Determine whether this directory exists.
@@ -601,15 +595,19 @@ const FileEntry *DirectoryLookup::DoFrameworkLookup(
     bool IsSystem = getDirCharacteristic() != SrcMgr::C_User;
     if (FoundFramework) {
       if (!HS.findUsableModuleForFrameworkHeader(
-              FE, FrameworkPath, RequestingModule, SuggestedModule, IsSystem))
-        return nullptr;
+              &File->getFileEntry(), FrameworkPath, RequestingModule,
+              SuggestedModule, IsSystem))
+        return None;
     } else {
-      if (!HS.findUsableModuleForHeader(FE, getDir(), RequestingModule,
-                                        SuggestedModule, IsSystem))
-        return nullptr;
+      if (!HS.findUsableModuleForHeader(&File->getFileEntry(), getDir(),
+                                        RequestingModule, SuggestedModule,
+                                        IsSystem))
+        return None;
     }
   }
-  return FE;
+  if (File)
+    return *File;
+  return None;
 }
 
 void HeaderSearch::setTarget(const TargetInfo &Target) {
@@ -714,7 +712,7 @@ diagnoseFrameworkInclude(DiagnosticsEngine &Diags, SourceLocation IncludeLoc,
 /// for system \#include's or not (i.e. using <> instead of ""). Includers, if
 /// non-empty, indicates where the \#including file(s) are, in case a relative
 /// search is needed. Microsoft mode will pass all \#including files.
-const FileEntry *HeaderSearch::LookupFile(
+Optional<FileEntryRef> HeaderSearch::LookupFile(
     StringRef Filename, SourceLocation IncludeLoc, bool isAngled,
     const DirectoryLookup *FromDir, const DirectoryLookup *&CurDir,
     ArrayRef<std::pair<const FileEntry *, const DirectoryEntry *>> Includers,
@@ -736,7 +734,8 @@ const FileEntry *HeaderSearch::LookupFile(
     CurDir = nullptr;
 
     // If this was an #include_next "/absolute/file", fail.
-    if (FromDir) return nullptr;
+    if (FromDir)
+      return None;
 
     if (SearchPath)
       SearchPath->clear();
@@ -751,8 +750,9 @@ const FileEntry *HeaderSearch::LookupFile(
   }
 
   // This is the header that MSVC's header search would have found.
-  const FileEntry *MSFE = nullptr;
   ModuleMap::KnownHeader MSSuggestedModule;
+  const FileEntry *MSFE_FE = nullptr;
+  StringRef MSFE_Name;
 
   // Unless disabled, check to see if the file is in the #includer's
   // directory.  This cannot be based on CurDir, because each includer could be
@@ -781,7 +781,7 @@ const FileEntry *HeaderSearch::LookupFile(
       bool IncluderIsSystemHeader =
           Includer ? getFileInfo(Includer).DirInfo != SrcMgr::C_User :
           BuildSystemModule;
-      if (const FileEntry *FE = getFileAndSuggestModule(
+      if (Optional<FileEntryRef> FE = getFileAndSuggestModule(
               TmpDir, IncludeLoc, IncluderAndDir.second, IncluderIsSystemHeader,
               RequestingModule, SuggestedModule)) {
         if (!Includer) {
@@ -800,7 +800,7 @@ const FileEntry *HeaderSearch::LookupFile(
         bool IndexHeaderMapHeader = FromHFI.IndexHeaderMapHeader;
         StringRef Framework = FromHFI.Framework;
 
-        HeaderFileInfo &ToHFI = getFileInfo(FE);
+        HeaderFileInfo &ToHFI = getFileInfo(&FE->getFileEntry());
         ToHFI.DirInfo = DirInfo;
         ToHFI.IndexHeaderMapHeader = IndexHeaderMapHeader;
         ToHFI.Framework = Framework;
@@ -817,7 +817,7 @@ const FileEntry *HeaderSearch::LookupFile(
         if (First) {
           diagnoseFrameworkInclude(Diags, IncludeLoc,
                                    IncluderAndDir.second->getName(), Filename,
-                                   FE);
+                                   &FE->getFileEntry());
           return FE;
         }
 
@@ -827,7 +827,8 @@ const FileEntry *HeaderSearch::LookupFile(
         if (Diags.isIgnored(diag::ext_pp_include_search_ms, IncludeLoc)) {
           return FE;
         } else {
-          MSFE = FE;
+          MSFE_FE = &FE->getFileEntry();
+          MSFE_Name = FE->getName();
           if (SuggestedModule) {
             MSSuggestedModule = *SuggestedModule;
             *SuggestedModule = ModuleMap::KnownHeader();
@@ -839,6 +840,9 @@ const FileEntry *HeaderSearch::LookupFile(
     }
   }
 
+  Optional<FileEntryRef> MSFE(MSFE_FE ? FileEntryRef(MSFE_Name, *MSFE_FE)
+                                      : Optional<FileEntryRef>());
+
   CurDir = nullptr;
 
   // If this is a system #include, ignore the user #include locs.
@@ -880,7 +884,7 @@ const FileEntry *HeaderSearch::LookupFile(
     bool InUserSpecifiedSystemFramework = false;
     bool HasBeenMapped = false;
     bool IsFrameworkFoundInDir = false;
-    const FileEntry *FE = SearchDirs[i].LookupFile(
+    Optional<FileEntryRef> File = SearchDirs[i].LookupFile(
         Filename, *this, IncludeLoc, SearchPath, RelativePath, RequestingModule,
         SuggestedModule, InUserSpecifiedSystemFramework, IsFrameworkFoundInDir,
         HasBeenMapped, MappedName);
@@ -895,12 +899,13 @@ const FileEntry *HeaderSearch::LookupFile(
       // lookups, ignore IsFrameworkFoundInDir after the first remapping and not
       // just for remapping in a current search directory.
       *IsFrameworkFound |= (IsFrameworkFoundInDir && !CacheLookup.MappedName);
-    if (!FE) continue;
+    if (!File)
+      continue;
 
     CurDir = &SearchDirs[i];
 
     // This file is a system header or C++ unfriendly if the dir is.
-    HeaderFileInfo &HFI = getFileInfo(FE);
+    HeaderFileInfo &HFI = getFileInfo(&File->getFileEntry());
     HFI.DirInfo = CurDir->getDirCharacteristic();
 
     // If the directory characteristic is User but this framework was
@@ -930,7 +935,8 @@ const FileEntry *HeaderSearch::LookupFile(
       }
     }
 
-    if (checkMSVCHeaderSearch(Diags, MSFE, FE, IncludeLoc)) {
+    if (checkMSVCHeaderSearch(Diags, MSFE ? &MSFE->getFileEntry() : nullptr,
+                              &File->getFileEntry(), IncludeLoc)) {
       if (SuggestedModule)
         *SuggestedModule = MSSuggestedModule;
       return MSFE;
@@ -938,13 +944,13 @@ const FileEntry *HeaderSearch::LookupFile(
 
     bool FoundByHeaderMap = !IsMapped ? false : *IsMapped;
     if (!Includers.empty())
-      diagnoseFrameworkInclude(Diags, IncludeLoc,
-                               Includers.front().second->getName(), Filename,
-                               FE, isAngled, FoundByHeaderMap);
+      diagnoseFrameworkInclude(
+          Diags, IncludeLoc, Includers.front().second->getName(), Filename,
+          &File->getFileEntry(), isAngled, FoundByHeaderMap);
 
     // Remember this location for the next lookup we do.
     CacheLookup.HitIdx = i;
-    return FE;
+    return File;
   }
 
   // If we are including a file with a quoted include "foo.h" from inside
@@ -960,12 +966,14 @@ const FileEntry *HeaderSearch::LookupFile(
       ScratchFilename += '/';
       ScratchFilename += Filename;
 
-      const FileEntry *FE = LookupFile(
+      Optional<FileEntryRef> File = LookupFile(
           ScratchFilename, IncludeLoc, /*isAngled=*/true, FromDir, CurDir,
           Includers.front(), SearchPath, RelativePath, RequestingModule,
           SuggestedModule, IsMapped, /*IsFrameworkFound=*/nullptr);
 
-      if (checkMSVCHeaderSearch(Diags, MSFE, FE, IncludeLoc)) {
+      if (checkMSVCHeaderSearch(Diags, MSFE ? &MSFE->getFileEntry() : nullptr,
+                                File ? &File->getFileEntry() : nullptr,
+                                IncludeLoc)) {
         if (SuggestedModule)
           *SuggestedModule = MSSuggestedModule;
         return MSFE;
@@ -974,11 +982,12 @@ const FileEntry *HeaderSearch::LookupFile(
       LookupFileCacheInfo &CacheLookup = LookupFileCache[Filename];
       CacheLookup.HitIdx = LookupFileCache[ScratchFilename].HitIdx;
       // FIXME: SuggestedModule.
-      return FE;
+      return File;
     }
   }
 
-  if (checkMSVCHeaderSearch(Diags, MSFE, nullptr, IncludeLoc)) {
+  if (checkMSVCHeaderSearch(Diags, MSFE ? &MSFE->getFileEntry() : nullptr,
+                            nullptr, IncludeLoc)) {
     if (SuggestedModule)
       *SuggestedModule = MSSuggestedModule;
     return MSFE;
@@ -986,7 +995,7 @@ const FileEntry *HeaderSearch::LookupFile(
 
   // Otherwise, didn't find it. Remember we didn't find this.
   CacheLookup.HitIdx = SearchDirs.size();
-  return nullptr;
+  return None;
 }
 
 /// LookupSubframeworkHeader - Look up a subframework for the specified
@@ -994,19 +1003,17 @@ const FileEntry *HeaderSearch::LookupFile(
 /// within ".../Carbon.framework/Headers/Carbon.h", check to see if HIToolbox
 /// is a subframework within Carbon.framework.  If so, return the FileEntry
 /// for the designated file, otherwise return null.
-const FileEntry *HeaderSearch::
-LookupSubframeworkHeader(StringRef Filename,
-                         const FileEntry *ContextFileEnt,
-                         SmallVectorImpl<char> *SearchPath,
-                         SmallVectorImpl<char> *RelativePath,
-                         Module *RequestingModule,
-                         ModuleMap::KnownHeader *SuggestedModule) {
+Optional<FileEntryRef> HeaderSearch::LookupSubframeworkHeader(
+    StringRef Filename, const FileEntry *ContextFileEnt,
+    SmallVectorImpl<char> *SearchPath, SmallVectorImpl<char> *RelativePath,
+    Module *RequestingModule, ModuleMap::KnownHeader *SuggestedModule) {
   assert(ContextFileEnt && "No context file?");
 
   // Framework names must have a '/' in the filename.  Find it.
   // FIXME: Should we permit '\' on Windows?
   size_t SlashPos = Filename.find('/');
-  if (SlashPos == StringRef::npos) return nullptr;
+  if (SlashPos == StringRef::npos)
+    return None;
 
   // Look up the base framework name of the ContextFileEnt.
   StringRef ContextName = ContextFileEnt->getName();
@@ -1017,7 +1024,7 @@ LookupSubframeworkHeader(StringRef Filename,
   if (FrameworkPos == StringRef::npos ||
       (ContextName[FrameworkPos + DotFrameworkLen] != '/' &&
        ContextName[FrameworkPos + DotFrameworkLen] != '\\'))
-    return nullptr;
+    return None;
 
   SmallString<1024> FrameworkName(ContextName.data(), ContextName.data() +
                                                           FrameworkPos +
@@ -1037,7 +1044,7 @@ LookupSubframeworkHeader(StringRef Filename,
       CacheLookup.first().size() == FrameworkName.size() &&
       memcmp(CacheLookup.first().data(), &FrameworkName[0],
              CacheLookup.first().size()) != 0)
-    return nullptr;
+    return None;
 
   // Cache subframework.
   if (!CacheLookup.second.Directory) {
@@ -1045,14 +1052,14 @@ LookupSubframeworkHeader(StringRef Filename,
 
     // If the framework dir doesn't exist, we fail.
     auto Dir = FileMgr.getDirectory(FrameworkName);
-    if (!Dir) return nullptr;
+    if (!Dir)
+      return None;
 
     // Otherwise, if it does, remember that this is the right direntry for this
     // framework.
     CacheLookup.second.Directory = *Dir;
   }
 
-  const FileEntry *FE = nullptr;
 
   if (RelativePath) {
     RelativePath->clear();
@@ -1069,10 +1076,10 @@ LookupSubframeworkHeader(StringRef Filename,
   }
 
   HeadersFilename.append(Filename.begin()+SlashPos+1, Filename.end());
-  if (auto File = FileMgr.getFile(HeadersFilename, /*OpenFile=*/true))
-    FE = *File;
+  llvm::ErrorOr<FileEntryRef> File =
+      FileMgr.getFileRef(HeadersFilename, /*OpenFile=*/true);
 
-  if (!FE) {
+  if (!File) {
     // Check ".../Frameworks/HIToolbox.framework/PrivateHeaders/HIToolbox.h"
     HeadersFilename = FrameworkName;
     HeadersFilename += "PrivateHeaders/";
@@ -1083,11 +1090,10 @@ LookupSubframeworkHeader(StringRef Filename,
     }
 
     HeadersFilename.append(Filename.begin()+SlashPos+1, Filename.end());
-    if (auto File = FileMgr.getFile(HeadersFilename, /*OpenFile=*/true))
-      FE = *File;
-  
-    if (!FE)
-      return nullptr;
+    File = FileMgr.getFileRef(HeadersFilename, /*OpenFile=*/true);
+
+    if (!File)
+      return None;
   }
 
   // This file is a system header or C++ unfriendly if the old file is.
@@ -1096,14 +1102,15 @@ LookupSubframeworkHeader(StringRef Filename,
   // getFileInfo could resize the vector and we don't want to rely on order
   // of evaluation.
   unsigned DirInfo = getFileInfo(ContextFileEnt).DirInfo;
-  getFileInfo(FE).DirInfo = DirInfo;
+  getFileInfo(&File->getFileEntry()).DirInfo = DirInfo;
 
   FrameworkName.pop_back(); // remove the trailing '/'
-  if (!findUsableModuleForFrameworkHeader(FE, FrameworkName, RequestingModule,
-                                          SuggestedModule, /*IsSystem*/ false))
-    return nullptr;
+  if (!findUsableModuleForFrameworkHeader(&File->getFileEntry(), FrameworkName,
+                                          RequestingModule, SuggestedModule,
+                                          /*IsSystem*/ false))
+    return None;
 
-  return FE;
+  return *File;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index 876090136d5..2642807b731 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -679,7 +679,7 @@ Preprocessor::getModuleHeaderToIncludeForDiagnostics(SourceLocation IncLoc,
   return nullptr;
 }
 
-const FileEntry *Preprocessor::LookupFile(
+Optional<FileEntryRef> Preprocessor::LookupFile(
     SourceLocation FilenameLoc, StringRef Filename, bool isAngled,
     const DirectoryLookup *FromDir, const FileEntry *FromFile,
     const DirectoryLookup *&CurDir, SmallVectorImpl<char> *SearchPath,
@@ -740,7 +740,7 @@ const FileEntry *Preprocessor::LookupFile(
     // the include path until we find that file or run out of files.
     const DirectoryLookup *TmpCurDir = CurDir;
     const DirectoryLookup *TmpFromDir = nullptr;
-    while (const FileEntry *FE = HeaderInfo.LookupFile(
+    while (Optional<FileEntryRef> FE = HeaderInfo.LookupFile(
                Filename, FilenameLoc, isAngled, TmpFromDir, TmpCurDir,
                Includers, SearchPath, RelativePath, RequestingModule,
                SuggestedModule, /*IsMapped=*/nullptr,
@@ -748,7 +748,7 @@ const FileEntry *Preprocessor::LookupFile(
       // Keep looking as if this file did a #include_next.
       TmpFromDir = TmpCurDir;
       ++TmpFromDir;
-      if (FE == FromFile) {
+      if (&FE->getFileEntry() == FromFile) {
         // Found it.
         FromDir = TmpFromDir;
         CurDir = TmpCurDir;
@@ -758,7 +758,7 @@ const FileEntry *Preprocessor::LookupFile(
   }
 
   // Do a standard file entry lookup.
-  const FileEntry *FE = HeaderInfo.LookupFile(
+  Optional<FileEntryRef> FE = HeaderInfo.LookupFile(
       Filename, FilenameLoc, isAngled, FromDir, CurDir, Includers, SearchPath,
       RelativePath, RequestingModule, SuggestedModule, IsMapped,
       IsFrameworkFound, SkipCache, BuildSystemModule);
@@ -766,7 +766,7 @@ const FileEntry *Preprocessor::LookupFile(
     if (SuggestedModule && !LangOpts.AsmPreprocessor)
       HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
           RequestingModule, RequestingModuleIsModuleInterface, FilenameLoc,
-          Filename, FE);
+          Filename, &FE->getFileEntry());
     return FE;
   }
 
@@ -776,14 +776,13 @@ const FileEntry *Preprocessor::LookupFile(
   // headers on the #include stack and pass them to HeaderInfo.
   if (IsFileLexer()) {
     if ((CurFileEnt = CurPPLexer->getFileEntry())) {
-      if ((FE = HeaderInfo.LookupSubframeworkHeader(Filename, CurFileEnt,
-                                                    SearchPath, RelativePath,
-                                                    RequestingModule,
-                                                    SuggestedModule))) {
+      if (Optional<FileEntryRef> FE = HeaderInfo.LookupSubframeworkHeader(
+              Filename, CurFileEnt, SearchPath, RelativePath, RequestingModule,
+              SuggestedModule)) {
         if (SuggestedModule && !LangOpts.AsmPreprocessor)
           HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
               RequestingModule, RequestingModuleIsModuleInterface, FilenameLoc,
-              Filename, FE);
+              Filename, &FE->getFileEntry());
         return FE;
       }
     }
@@ -792,13 +791,13 @@ const FileEntry *Preprocessor::LookupFile(
   for (IncludeStackInfo &ISEntry : llvm::reverse(IncludeMacroStack)) {
     if (IsFileLexer(ISEntry)) {
       if ((CurFileEnt = ISEntry.ThePPLexer->getFileEntry())) {
-        if ((FE = HeaderInfo.LookupSubframeworkHeader(
+        if (Optional<FileEntryRef> FE = HeaderInfo.LookupSubframeworkHeader(
                 Filename, CurFileEnt, SearchPath, RelativePath,
-                RequestingModule, SuggestedModule))) {
+                RequestingModule, SuggestedModule)) {
           if (SuggestedModule && !LangOpts.AsmPreprocessor)
             HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
                 RequestingModule, RequestingModuleIsModuleInterface,
-                FilenameLoc, Filename, FE);
+                FilenameLoc, Filename, &FE->getFileEntry());
           return FE;
         }
       }
@@ -806,7 +805,7 @@ const FileEntry *Preprocessor::LookupFile(
   }
 
   // Otherwise, we really couldn't find the file.
-  return nullptr;
+  return None;
 }
 
 //===----------------------------------------------------------------------===//
@@ -1676,6 +1675,130 @@ void Preprocessor::HandleIncludeDirective(SourceLocation HashLoc,
   }
 }
 
+Optional<FileEntryRef> Preprocessor::LookupHeaderIncludeOrImport(
+    const DirectoryLookup *&CurDir, StringRef Filename,
+    SourceLocation FilenameLoc, CharSourceRange FilenameRange,
+    const Token &FilenameTok, bool &IsFrameworkFound, bool IsImportDecl,
+    bool &IsMapped, const DirectoryLookup *LookupFrom,
+    const FileEntry *LookupFromFile, SmallString<128> &NormalizedPath,
+    SmallVectorImpl<char> &RelativePath, SmallVectorImpl<char> &SearchPath,
+    ModuleMap::KnownHeader &SuggestedModule, bool isAngled) {
+  Optional<FileEntryRef> File = LookupFile(
+      FilenameLoc, LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename,
+      isAngled, LookupFrom, LookupFromFile, CurDir,
+      Callbacks ? &SearchPath : nullptr, Callbacks ? &RelativePath : nullptr,
+      &SuggestedModule, &IsMapped, &IsFrameworkFound);
+  if (File)
+    return File;
+
+  if (Callbacks) {
+    // Give the clients a chance to recover.
+    SmallString<128> RecoveryPath;
+    if (Callbacks->FileNotFound(Filename, RecoveryPath)) {
+      if (auto DE = FileMgr.getDirectory(RecoveryPath)) {
+        // Add the recovery path to the list of search paths.
+        DirectoryLookup DL(*DE, SrcMgr::C_User, false);
+        HeaderInfo.AddSearchPath(DL, isAngled);
+
+        // Try the lookup again, skipping the cache.
+        Optional<FileEntryRef> File = LookupFile(
+            FilenameLoc,
+            LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename, isAngled,
+            LookupFrom, LookupFromFile, CurDir, nullptr, nullptr,
+            &SuggestedModule, &IsMapped, /*IsFrameworkFound=*/nullptr,
+            /*SkipCache*/ true);
+        if (File)
+          return File;
+      }
+    }
+  }
+
+  if (SuppressIncludeNotFoundError)
+    return None;
+
+  // If the file could not be located and it was included via angle
+  // brackets, we can attempt a lookup as though it were a quoted path to
+  // provide the user with a possible fixit.
+  if (isAngled) {
+    Optional<FileEntryRef> File = LookupFile(
+        FilenameLoc, LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename,
+        false, LookupFrom, LookupFromFile, CurDir,
+        Callbacks ? &SearchPath : nullptr, Callbacks ? &RelativePath : nullptr,
+        &SuggestedModule, &IsMapped,
+        /*IsFrameworkFound=*/nullptr);
+    if (File) {
+      Diag(FilenameTok, diag::err_pp_file_not_found_angled_include_not_fatal)
+          << Filename << IsImportDecl
+          << FixItHint::CreateReplacement(FilenameRange,
+                                          "\"" + Filename.str() + "\"");
+      return File;
+    }
+  }
+
+  // Check for likely typos due to leading or trailing non-isAlphanumeric
+  // characters
+  StringRef OriginalFilename = Filename;
+  if (LangOpts.SpellChecking) {
+    // A heuristic to correct a typo file name by removing leading and
+    // trailing non-isAlphanumeric characters.
+    auto CorrectTypoFilename = [](llvm::StringRef Filename) {
+      Filename = Filename.drop_until(isAlphanumeric);
+      while (!Filename.empty() && !isAlphanumeric(Filename.back())) {
+        Filename = Filename.drop_back();
+      }
+      return Filename;
+    };
+    StringRef TypoCorrectionName = CorrectTypoFilename(Filename);
+    SmallString<128> NormalizedTypoCorrectionPath;
+    if (LangOpts.MSVCCompat) {
+      NormalizedTypoCorrectionPath = TypoCorrectionName.str();
+#ifndef _WIN32
+      llvm::sys::path::native(NormalizedTypoCorrectionPath);
+#endif
+    }
+    Optional<FileEntryRef> File = LookupFile(
+        FilenameLoc,
+        LangOpts.MSVCCompat ? NormalizedTypoCorrectionPath.c_str()
+                            : TypoCorrectionName,
+        isAngled, LookupFrom, LookupFromFile, CurDir,
+        Callbacks ? &SearchPath : nullptr, Callbacks ? &RelativePath : nullptr,
+        &SuggestedModule, &IsMapped,
+        /*IsFrameworkFound=*/nullptr);
+    if (File) {
+      auto Hint =
+          isAngled ? FixItHint::CreateReplacement(
+                         FilenameRange, "<" + TypoCorrectionName.str() + ">")
+                   : FixItHint::CreateReplacement(
+                         FilenameRange, "\"" + TypoCorrectionName.str() + "\"");
+      Diag(FilenameTok, diag::err_pp_file_not_found_typo_not_fatal)
+          << OriginalFilename << TypoCorrectionName << Hint;
+      // We found the file, so set the Filename to the name after typo
+      // correction.
+      Filename = TypoCorrectionName;
+      return File;
+    }
+  }
+
+  // If the file is still not found, just go with the vanilla diagnostic
+  assert(!File.hasValue() && "expected missing file");
+  Diag(FilenameTok, diag::err_pp_file_not_found)
+      << OriginalFilename << FilenameRange;
+  if (IsFrameworkFound) {
+    size_t SlashPos = OriginalFilename.find('/');
+    assert(SlashPos != StringRef::npos &&
+           "Include with framework name should have '/' in the filename");
+    StringRef FrameworkName = OriginalFilename.substr(0, SlashPos);
+    FrameworkCacheEntry &CacheEntry =
+        HeaderInfo.LookupFrameworkCache(FrameworkName);
+    assert(CacheEntry.Directory && "Found framework should be in cache");
+    Diag(FilenameTok, diag::note_pp_framework_without_header)
+        << OriginalFilename.substr(SlashPos + 1) << FrameworkName
+        << CacheEntry.Directory->getName();
+  }
+
+  return None;
+}
+
 /// Handle either a #include-like directive or an import declaration that names
 /// a header file.
 ///
@@ -1754,120 +1877,14 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
     llvm::sys::path::native(NormalizedPath);
 #endif
   }
-  const FileEntry *File = LookupFile(
-      FilenameLoc, LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename,
-      isAngled, LookupFrom, LookupFromFile, CurDir,
-      Callbacks ? &SearchPath : nullptr, Callbacks ? &RelativePath : nullptr,
-      &SuggestedModule, &IsMapped, &IsFrameworkFound);
-
-  if (!File) {
-    if (Callbacks) {
-      // Give the clients a chance to recover.
-      SmallString<128> RecoveryPath;
-      if (Callbacks->FileNotFound(Filename, RecoveryPath)) {
-        if (auto DE = FileMgr.getDirectory(RecoveryPath)) {
-          // Add the recovery path to the list of search paths.
-          DirectoryLookup DL(*DE, SrcMgr::C_User, false);
-          HeaderInfo.AddSearchPath(DL, isAngled);
-
-          // Try the lookup again, skipping the cache.
-          File = LookupFile(
-              FilenameLoc,
-              LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename, isAngled,
-              LookupFrom, LookupFromFile, CurDir, nullptr, nullptr,
-              &SuggestedModule, &IsMapped, /*IsFrameworkFound=*/nullptr,
-              /*SkipCache*/ true);
-        }
-      }
-    }
-
-    if (!SuppressIncludeNotFoundError) {
-      // If the file could not be located and it was included via angle
-      // brackets, we can attempt a lookup as though it were a quoted path to
-      // provide the user with a possible fixit.
-      if (isAngled) {
-        File = LookupFile(
-            FilenameLoc,
-            LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename, false,
-            LookupFrom, LookupFromFile, CurDir,
-            Callbacks ? &SearchPath : nullptr,
-            Callbacks ? &RelativePath : nullptr, &SuggestedModule, &IsMapped,
-            /*IsFrameworkFound=*/nullptr);
-        if (File) {
-          Diag(FilenameTok,
-               diag::err_pp_file_not_found_angled_include_not_fatal)
-              << Filename << IsImportDecl
-              << FixItHint::CreateReplacement(FilenameRange,
-                                              "\"" + Filename.str() + "\"");
-        }
-      }
 
-      // Check for likely typos due to leading or trailing non-isAlphanumeric
-      // characters
-      StringRef OriginalFilename = Filename;
-      if (LangOpts.SpellChecking && !File) {
-        // A heuristic to correct a typo file name by removing leading and
-        // trailing non-isAlphanumeric characters.
-        auto CorrectTypoFilename = [](llvm::StringRef Filename) {
-          Filename = Filename.drop_until(isAlphanumeric);
-          while (!Filename.empty() && !isAlphanumeric(Filename.back())) {
-            Filename = Filename.drop_back();
-          }
-          return Filename;
-        };
-        StringRef TypoCorrectionName = CorrectTypoFilename(Filename);
-        SmallString<128> NormalizedTypoCorrectionPath;
-        if (LangOpts.MSVCCompat) {
-          NormalizedTypoCorrectionPath = TypoCorrectionName.str();
-#ifndef _WIN32
-          llvm::sys::path::native(NormalizedTypoCorrectionPath);
-#endif
-        }
-        File = LookupFile(
-            FilenameLoc,
-            LangOpts.MSVCCompat ? NormalizedTypoCorrectionPath.c_str()
-                                : TypoCorrectionName,
-            isAngled, LookupFrom, LookupFromFile, CurDir,
-            Callbacks ? &SearchPath : nullptr,
-            Callbacks ? &RelativePath : nullptr, &SuggestedModule, &IsMapped,
-            /*IsFrameworkFound=*/nullptr);
-        if (File) {
-          auto Hint =
-              isAngled
-                  ? FixItHint::CreateReplacement(
-                        FilenameRange, "<" + TypoCorrectionName.str() + ">")
-                  : FixItHint::CreateReplacement(
-                        FilenameRange, "\"" + TypoCorrectionName.str() + "\"");
-          Diag(FilenameTok, diag::err_pp_file_not_found_typo_not_fatal)
-              << OriginalFilename << TypoCorrectionName << Hint;
-          // We found the file, so set the Filename to the name after typo
-          // correction.
-          Filename = TypoCorrectionName;
-        }
-      }
-
-      // If the file is still not found, just go with the vanilla diagnostic
-      if (!File) {
-        Diag(FilenameTok, diag::err_pp_file_not_found) << OriginalFilename
-                                                       << FilenameRange;
-        if (IsFrameworkFound) {
-          size_t SlashPos = OriginalFilename.find('/');
-          assert(SlashPos != StringRef::npos &&
-                 "Include with framework name should have '/' in the filename");
-          StringRef FrameworkName = OriginalFilename.substr(0, SlashPos);
-          FrameworkCacheEntry &CacheEntry =
-              HeaderInfo.LookupFrameworkCache(FrameworkName);
-          assert(CacheEntry.Directory && "Found framework should be in cache");
-          Diag(FilenameTok, diag::note_pp_framework_without_header)
-              << OriginalFilename.substr(SlashPos + 1) << FrameworkName
-              << CacheEntry.Directory->getName();
-        }
-      }
-    }
-  }
+  Optional<FileEntryRef> File = LookupHeaderIncludeOrImport(
+      CurDir, Filename, FilenameLoc, FilenameRange, FilenameTok,
+      IsFrameworkFound, IsImportDecl, IsMapped, LookupFrom, LookupFromFile,
+      NormalizedPath, RelativePath, SearchPath, SuggestedModule, isAngled);
 
   if (usingPCHWithThroughHeader() && SkippingUntilPCHThroughHeader) {
-    if (isPCHThroughHeader(File))
+    if (File && isPCHThroughHeader(&File->getFileEntry()))
       SkippingUntilPCHThroughHeader = false;
     return {ImportAction::None};
   }
@@ -1878,7 +1895,8 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   // some directives (e.g. #endif of a header guard) will never be seen.
   // Since this will lead to confusing errors, avoid the inclusion.
   if (File && PreambleConditionalStack.isRecording() &&
-      SourceMgr.translateFile(File) == SourceMgr.getMainFileID()) {
+      SourceMgr.translateFile(&File->getFileEntry()) ==
+          SourceMgr.getMainFileID()) {
     Diag(FilenameTok.getLocation(),
          diag::err_pp_including_mainfile_in_preamble);
     return {ImportAction::None};
@@ -1897,7 +1915,7 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   // include cycle. Don't enter already processed files again as it can lead to
   // reaching the max allowed include depth again.
   if (Action == Enter && HasReachedMaxIncludeDepth && File &&
-      HeaderInfo.getFileInfo(File).NumIncludes)
+      HeaderInfo.getFileInfo(&File->getFileEntry()).NumIncludes)
     Action = IncludeLimitReached;
 
   // Determine whether we should try to import the module for this #include, if
@@ -1973,7 +1991,8 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   SrcMgr::CharacteristicKind FileCharacter =
       SourceMgr.getFileCharacteristic(FilenameTok.getLocation());
   if (File)
-    FileCharacter = std::max(HeaderInfo.getFileDirFlavor(File), FileCharacter);
+    FileCharacter = std::max(HeaderInfo.getFileDirFlavor(&File->getFileEntry()),
+                             FileCharacter);
 
   // If this is a '#import' or an import-declaration, don't re-enter the file.
   //
@@ -1987,8 +2006,8 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   // Ask HeaderInfo if we should enter this #include file.  If not, #including
   // this file will have no effect.
   if (Action == Enter && File &&
-      !HeaderInfo.ShouldEnterIncludeFile(*this, File, EnterOnce,
-                                         getLangOpts().Modules,
+      !HeaderInfo.ShouldEnterIncludeFile(*this, &File->getFileEntry(),
+                                         EnterOnce, getLangOpts().Modules,
                                          SuggestedModule.getModule())) {
     // Even if we've already preprocessed this header once and know that we
     // don't need to see its contents again, we still need to import it if it's
@@ -2006,11 +2025,11 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
     Callbacks->InclusionDirective(
         HashLoc, IncludeTok,
         LangOpts.MSVCCompat ? NormalizedPath.c_str() : Filename, isAngled,
-        FilenameRange, File, SearchPath, RelativePath,
-        Action == Import ? SuggestedModule.getModule() : nullptr,
+        FilenameRange, File ? &File->getFileEntry() : nullptr, SearchPath,
+        RelativePath, Action == Import ? SuggestedModule.getModule() : nullptr,
         FileCharacter);
-    if (Action == Skip)
-      Callbacks->FileSkipped(*File, FilenameTok, FileCharacter);
+    if (Action == Skip && File)
+      Callbacks->FileSkipped(File->getFileEntry(), FilenameTok, FileCharacter);
   }
 
   if (!File)
@@ -2027,11 +2046,11 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   // Issue a diagnostic if the name of the file on disk has a different case
   // than the one we're about to open.
   const bool CheckIncludePathPortability =
-      !IsMapped && File && !File->tryGetRealPathName().empty();
+      !IsMapped && !File->getFileEntry().tryGetRealPathName().empty();
 
   if (CheckIncludePathPortability) {
     StringRef Name = LangOpts.MSVCCompat ? NormalizedPath.str() : Filename;
-    StringRef RealPathName = File->tryGetRealPathName();
+    StringRef RealPathName = File->getFileEntry().tryGetRealPathName();
     SmallVector<StringRef, 16> Components(llvm::sys::path::begin(Name),
                                           llvm::sys::path::end(Name));
 
@@ -2102,7 +2121,7 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   // position on the file where it will be included and after the expansions.
   if (IncludePos.isMacroID())
     IncludePos = SourceMgr.getExpansionRange(IncludePos).getEnd();
-  FileID FID = SourceMgr.createFileID(File, IncludePos, FileCharacter);
+  FileID FID = SourceMgr.createFileID(*File, IncludePos, FileCharacter);
   assert(FID.isValid() && "Expected valid file ID");
 
   // If all is good, enter the new file!
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 41fa2b0133c..3f5ee08b743 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1210,19 +1210,21 @@ static bool EvaluateHasIncludeCommon(Token &Tok,
 
   // Search include directories.
   const DirectoryLookup *CurDir;
-  const FileEntry *File =
+  Optional<FileEntryRef> File =
       PP.LookupFile(FilenameLoc, Filename, isAngled, LookupFrom, LookupFromFile,
                     CurDir, nullptr, nullptr, nullptr, nullptr, nullptr);
 
   if (PPCallbacks *Callbacks = PP.getPPCallbacks()) {
     SrcMgr::CharacteristicKind FileType = SrcMgr::C_User;
     if (File)
-      FileType = PP.getHeaderSearchInfo().getFileDirFlavor(File);
-    Callbacks->HasInclude(FilenameLoc, Filename, isAngled, File, FileType);
+      FileType =
+          PP.getHeaderSearchInfo().getFileDirFlavor(&File->getFileEntry());
+    Callbacks->HasInclude(FilenameLoc, Filename, isAngled,
+                          File ? &File->getFileEntry() : nullptr, FileType);
   }
 
   // Get the result value.  A result of true means the file exists.
-  return File != nullptr;
+  return File.hasValue();
 }
 
 /// EvaluateHasInclude - Process a '__has_include("path")' expression.
diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index 8317e99a4f6..64352334fcf 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -498,7 +498,7 @@ void Preprocessor::HandlePragmaDependency(Token &DependencyTok) {
 
   // Search include directories for this file.
   const DirectoryLookup *CurDir;
-  const FileEntry *File =
+  Optional<FileEntryRef> File =
       LookupFile(FilenameTok.getLocation(), Filename, isAngled, nullptr,
                  nullptr, CurDir, nullptr, nullptr, nullptr, nullptr, nullptr);
   if (!File) {
diff --git a/clang/lib/Lex/Preprocessor.cpp b/clang/lib/Lex/Preprocessor.cpp
index 6579319cb3f..3abd0c76d0f 100644
--- a/clang/lib/Lex/Preprocessor.cpp
+++ b/clang/lib/Lex/Preprocessor.cpp
@@ -563,7 +563,7 @@ void Preprocessor::EnterMainSourceFile() {
     // Lookup and save the FileID for the through header. If it isn't found
     // in the search path, it's a fatal error.
     const DirectoryLookup *CurDir;
-    const FileEntry *File = LookupFile(
+    Optional<FileEntryRef> File = LookupFile(
         SourceLocation(), PPOpts->PCHThroughHeader,
         /*isAngled=*/false, /*FromDir=*/nullptr, /*FromFile=*/nullptr, CurDir,
         /*SearchPath=*/nullptr, /*RelativePath=*/nullptr,
@@ -575,7 +575,7 @@ void Preprocessor::EnterMainSourceFile() {
       return;
     }
     setPCHThroughHeaderFileID(
-        SourceMgr.createFileID(File, SourceLocation(), SrcMgr::C_User));
+        SourceMgr.createFileID(*File, SourceLocation(), SrcMgr::C_User));
   }
 
   // Skip tokens from the Predefines and if needed the main file.