[PATCH] D37954: Expand absolute system header paths when using -MD depfiles

[Peter Wu via cfe-commits]

Hi Nico,

On Sun, Sep 17, 2017 at 10:47:24AM -0400, Nico Weber wrote:
> Have you checked how much the additional stat()ing added in this patch
> slows down builds?

Additional cost: zero :-)

The information is already collected by FileManager::getFile(), calling
tryGetRealPathName just reads information without extra stat() calls.

For the next patch revision I would have to either add documentation, or
remove the -fno-canonical-system-headers option. What would you
recommend?

Kind regards,
Peter

> On Sep 16, 2017 11:49 PM, "Peter Wu via Phabricator via cfe-commits" <
> cfe-commits at lists.llvm.org> wrote:
> 
> > Lekensteyn added a comment.
> >
> > I tried to contact Simon (the author of the GCC) patch with a question
> > about the -fno-canonical-system-headers, but his Google address is bouncing.
> >
> > GCC has long survived with doing this by default, I wonder if this option
> > could just me omitted, enabling the feature by default.
> >
> >
> > https://reviews.llvm.org/D37954
-- 
Kind regards,
Peter Wu
https://lekensteyn.nl