[PATCH] D128947: [Lex] Introduce `PPCallbacks::LexedFileChanged()` preprocessor callback

[Argyrios Kyrtzidis via Phabricator via cfe-commits]

akyrtzi added inline comments.


================
Comment at: clang/lib/Basic/SourceManager.cpp:1016
+    return *Name;
   return StringRef();
 }
----------------
benlangmuir wrote:
> Just a suggestion: `value_or` can be a nice way to express simple cases like this:
> 
> ```
> getFilename(getFileID(SpellingLoc)).value_or(StringRef());
> ```
Thank you for the tip!


================
Comment at: clang/lib/Lex/PPLexerChange.cpp:136
                            PPCallbacks::EnterFile, FileType);
+    FileID PrevFID;
+    SourceLocation EnterLoc;
----------------
benlangmuir wrote:
> Why does `LexedFileChanged` have `PrevFID` set, but `FileChanged` does not (it has a default argument of `FileID()`?  I would have expected that when you call both `FileChanged` and `LexedFileChanged` for the same event this would match.
I didn't want to change the "contract" of `FileChanged()` as part of these changes but it's probably unlikely that someone depends on `FileID` being invalid, I'll give it a try.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D128947/new/

https://reviews.llvm.org/D128947