[PATCH] D79834: Speed up preamble building by replacing the slow translateFile call by a new, faster isMainFile check

[Duncan P. N. Exon Smith via Phabricator via cfe-commits]

dexonsmith added inline comments.


================
Comment at: clang/lib/Basic/SourceManager.cpp:397
+    return false;
+  return FE->getUID() == SourceFile.getUID();
+}
----------------
arphaman wrote:
> jkorous wrote:
> > I don't really understand all the details here but shouldn't we use this comparison?
> > ```
> > bool operator==(const FileEntryRef &LHS, const FileEntryRef &RHS)
> > ```
> The `==` comparison can return false for symlinks due to the different name, but we want to return true for symlinks to the main file as well. 
I suggest adding a comment to the code explaining this when you land it, something like:

    // Compare UIDs directly so that symlinks compare equal.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D79834/new/

https://reviews.llvm.org/D79834