From cf593d224c9c3fc2cf93827cb66fd9e550a6a486 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Duncan=20P=2E=20N=2E=20Exon=C2=A0Smith?=
 <dexonsmith@apple.com>
Date: Thu, 15 Oct 2020 18:46:25 -0400
Subject: [PATCH] SourceManager: getFileEntryRefForID =>
 getNonBuiltinFilenameForID, NFC

`SourceManager::getFileEntryRefForID`'s remaining callers just want the
filename component, which is coming from the `FileInfo`. Replace the API
with `getNonBuiltinFilenameForID`, which also removes another use of
`FileEntryRef::FileEntryRef` outside of `FileManager`.

Both callers are collecting file dependencies, and one of them relied on
this API to filter out built-ins (as exposed by
clang/test/ClangScanDeps/modules-full.cpp). It seems nice to continue
providing that service.

Differential Revision: https://reviews.llvm.org/D89508
---
 clang/include/clang/Basic/SourceManager.h       |  7 +++++--
 clang/lib/Basic/SourceManager.cpp               |  5 +++--
 clang/lib/Frontend/DependencyFile.cpp           | 17 ++++++-----------
 .../DependencyScanning/ModuleDepCollector.cpp   | 13 ++++---------
 4 files changed, 18 insertions(+), 24 deletions(-)

diff --git a/clang/include/clang/Basic/SourceManager.h b/clang/include/clang/Basic/SourceManager.h
index 93eee503a8e5..5035326297f7 100644
--- a/clang/include/clang/Basic/SourceManager.h
+++ b/clang/include/clang/Basic/SourceManager.h
@@ -997,8 +997,11 @@ public:
     return nullptr;
   }
 
-  /// Returns the FileEntryRef for the provided FileID.
-  Optional<FileEntryRef> getFileEntryRefForID(FileID FID) const;
+  /// Returns the filename for the provided FileID, unless it's a built-in
+  /// buffer that's not represented by a filename.
+  ///
+  /// Returns None for non-files and built-in files.
+  Optional<StringRef> getNonBuiltinFilenameForID(FileID FID) const;
 
   /// Returns the FileEntry record for the provided SLocEntry.
   const FileEntry *getFileEntryForSLocEntry(const SrcMgr::SLocEntry &sloc) const
diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index c91ef41979bc..79eeeb29d6b9 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -725,11 +725,12 @@ void SourceManager::setFileIsTransient(const FileEntry *File) {
   const_cast<SrcMgr::ContentCache *>(CC)->IsTransient = true;
 }
 
-Optional<FileEntryRef> SourceManager::getFileEntryRefForID(FileID FID) const {
+Optional<StringRef>
+SourceManager::getNonBuiltinFilenameForID(FileID FID) const {
   if (const SrcMgr::SLocEntry *Entry = getSLocEntryForFile(FID))
     if (auto *Content = Entry->getFile().getContentCache())
       if (Content && Content->OrigEntry)
-        return FileEntryRef(Entry->getFile().getName(), *Content->OrigEntry);
+        return Entry->getFile().getName();
   return None;
 }
 
diff --git a/clang/lib/Frontend/DependencyFile.cpp b/clang/lib/Frontend/DependencyFile.cpp
index c9240f4122a7..fe8ab7197400 100644
--- a/clang/lib/Frontend/DependencyFile.cpp
+++ b/clang/lib/Frontend/DependencyFile.cpp
@@ -46,17 +46,12 @@ struct DepCollectorPPCallbacks : public PPCallbacks {
     // Dependency generation really does want to go all the way to the
     // file entry for a source location to find out what is depended on.
     // We do not want #line markers to affect dependency generation!
-    Optional<FileEntryRef> File =
-        SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(Loc)));
-    if (!File)
-      return;
-
-    StringRef Filename =
-        llvm::sys::path::remove_leading_dotslash(File->getName());
-
-    DepCollector.maybeAddDependency(Filename, /*FromModule*/false,
-                                    isSystem(FileType),
-                                    /*IsModuleFile*/false, /*IsMissing*/false);
+    if (Optional<StringRef> Filename = SM.getNonBuiltinFilenameForID(
+            SM.getFileID(SM.getExpansionLoc(Loc))))
+      DepCollector.maybeAddDependency(
+          llvm::sys::path::remove_leading_dotslash(*Filename),
+          /*FromModule*/ false, isSystem(FileType), /*IsModuleFile*/ false,
+          /*IsMissing*/ false);
   }
 
   void FileSkipped(const FileEntryRef &SkippedFile, const Token &FilenameTok,
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 4f6eff799f22..f74ce7304df5 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -77,15 +77,10 @@ void ModuleDepCollectorPP::FileChanged(SourceLocation Loc,
   // Dependency generation really does want to go all the way to the
   // file entry for a source location to find out what is depended on.
   // We do not want #line markers to affect dependency generation!
-  Optional<FileEntryRef> File =
-      SM.getFileEntryRefForID(SM.getFileID(SM.getExpansionLoc(Loc)));
-  if (!File)
-    return;
-
-  StringRef FileName =
-      llvm::sys::path::remove_leading_dotslash(File->getName());
-
-  MDC.MainDeps.push_back(std::string(FileName));
+  if (Optional<StringRef> Filename =
+          SM.getNonBuiltinFilenameForID(SM.getFileID(SM.getExpansionLoc(Loc))))
+    MDC.MainDeps.push_back(
+        std::string(llvm::sys::path::remove_leading_dotslash(*Filename)));
 }
 
 void ModuleDepCollectorPP::InclusionDirective(