[clang][lex] NFCI: Use DirectoryEntryRef in Preprocessor::MainFileDir

[jansvoboda11]

Summary

This patch changes the type of Preprocessor::MainFileDir from const DirectoryEntry * to Optional<DirectoryEntryRef> in order to remove some calls to the deprecated DirectoryEntry::getName().

Depends on D127658.

[bnbarham]

clang/lib/Frontend/FrontendAction.cpp

514

Same as in previous review, is this guaranteed to be set? Might be worth a comment on the field itself if so (in https://reviews.llvm.org/D127654)

[jansvoboda11]

clang/lib/Frontend/FrontendAction.cpp

514

It is. Couple lines above we call HeaderSearch::lookupModule(), which parses the defining module map and sets the Directory.

clang/include/clang/Lex/Preprocessor.h

private:
   IdentifierInfo *CodeCompletionII = nullptr;
 
   /// Range for the code completion token.
   SourceRange CodeCompletionTokenRange;
 
   /// The directory that the main file should be considered to occupy,
   /// if it does not correspond to a real file (as happens when building a
   /// module).
-  const DirectoryEntry *MainFileDir = nullptr;
+  OptionalDirectoryEntryRef MainFileDir;
 
   /// The number of bytes that we will initially skip when entering the
   /// main file, along with a flag that indicates whether skipping this number
   /// of bytes will place the lexer at the start of a line.
   ///
   /// This is used when loading a precompiled preamble.
   std::pair<int, bool> SkipMainFilePreamble;
 
public:
   /// Record the location of the unterminated \#pragma clang
   /// assume_nonnull begin in the preamble.
   void setPreambleRecordedPragmaAssumeNonNullLoc(SourceLocation Loc) {
     PreambleRecordedPragmaAssumeNonNullLoc = Loc;
   }
 
   /// Set the directory in which the main file should be considered
   /// to have been found, if it is not a real file.
-  void setMainFileDir(const DirectoryEntry *Dir) {
-    MainFileDir = Dir;
-  }
+  void setMainFileDir(DirectoryEntryRef Dir) { MainFileDir = Dir; }
 
   /// Instruct the preprocessor to skip part of the main source file.
   ///
   /// \param Bytes The number of bytes in the preamble to skip.
   ///
   /// \param StartOfLine Whether skipping these bytes puts the lexer at the
   /// start of a line.
   void setSkipMainFilePreamble(unsigned Bytes, bool StartOfLine) {

clang/lib/Frontend/FrontendAction.cpp

static Module *prepareToBuildModule(CompilerInstance &CI,
 
   // Check whether we can build this module at all.
   if (Preprocessor::checkModuleIsAvailable(CI.getLangOpts(), CI.getTarget(),
                                            CI.getDiagnostics(), M))
     return nullptr;
 
   // Inform the preprocessor that includes from within the input buffer should
   // be resolved relative to the build directory of the module map file.
-  CI.getPreprocessor().setMainFileDir(M->Directory);
+  CI.getPreprocessor().setMainFileDir(*M->Directory);
 
   // If the module was inferred from a different module map (via an expanded
   // umbrella module definition), track that fact.
   // FIXME: It would be preferable to fill this in as part of processing
   // the module map, rather than adding it after the fact.
   StringRef OriginalModuleMapName = CI.getFrontendOpts().OriginalModuleMap;
   if (!OriginalModuleMapName.empty()) {
     auto OriginalModuleMap =

clang/lib/Lex/PPDirectives.cpp

if (!FromDir && !FromFile) {
     // from the -include command line argument) from the current working
     // directory instead of relative to the main file.
     //
     // If we have the module includes buffer, resolve #include references (which
     // come from header declarations in the module map) relative to the module
     // map file.
     if (!FileEnt) {
       if (FID == SourceMgr.getMainFileID() && MainFileDir) {
-        Includers.push_back(std::make_pair(nullptr, MainFileDir));
+        Includers.push_back(std::make_pair(nullptr, *MainFileDir));
         BuildSystemModule = getCurrentModule()->IsSystem;
       } else if ((FileEnt =
                     SourceMgr.getFileEntryForID(SourceMgr.getMainFileID())))
         Includers.push_back(std::make_pair(FileEnt, *FileMgr.getDirectory(".")));
     } else {
       Includers.push_back(std::make_pair(FileEnt, FileEnt->getDir()));
     }