[cfe-dev] New warning for mismatched include case

[Matthieu Monrocq]

On Mon, Jul 23, 2012 at 6:16 PM, Jason Haslam <jason.haslam at gmail.com>wrote:

> This updated patch adds a fixit and a test. The test fails on
> case-sensitive systems. Is it possible to test for an error on some
> platforms and a warning on others?
>
> Jason
>

There is a preprocessor directive to test for the presence of include
files: __has_include I think.

#if __has_include(<IOSTREAM>)
#  include <IOSTREAM>
#endif

should make it so that the #include is only processed on file systems where
<IOSTREAM> was found (which excludes case-sensitives file systems).

-- Matthieu


>
>
>
>
>
> On Jul 19, 2012, at 11:58 PM, Jason Haslam wrote:
>
> > Okay, I added caching which improved performance some. I also changed it
> to only check in user code, which made the Cocoa.h test case moot. I've run
> the attached patch over real code from LLVM and I don't see any measurable
> performance difference. It still may be worth disabling the check on
> case-sensitive file systems, although I'm not entirely sure how to do that
> beyond "#if defined(__APPLE__) || defined(_WIN32)".
> >
> > If this looks like the right direction then I'll try to address some of
> the other concerns.
> >
> > Jason
> >
> > <include_case.diff>
> >
> >
> > On Jul 18, 2012, at 11:26 PM, Jason Haslam wrote:
> >
> >> Yes, performance is definitely an issue. I see about 30% degradation on
> Cocoa.h with this naive implementation. That's probably not going to fly
> under any circumstance. I'll take a closer look...
> >>
> >> Jason
> >>
> >>
> >> On Jul 18, 2012, at 5:12 PM, Ted Kremenek wrote:
> >>
> >>> Hi Jason,
> >>>
> >>> Any idea what is the performance impact of this change?  My concern
> that this is potentially expensive, and we shouldn't be performing the
> check on a case-sensitve file system (if we can help it).  That said, many
> people have requested this kind of checking, so I'm happy to see you taking
> a stab at it.
> >>>
> >>> Ted
> >>>
> >>> On Jul 18, 2012, at 3:09 PM, Jason Haslam <jason.haslam at gmail.com>
> wrote:
> >>>
> >>>> The attached (incomplete proof-of-concept) patch provides a new
> warning that fires on case-insensitive file systems when the case of the
> file name in the #include directive doesn't match the case of the file name
> on disk. The idea is to avoid broken commits that fail to build on
> case-sensitive file systems. For example:
> >>>>
> >>>> jason$ ls
> >>>> test.cpp test.h
> >>>> jason$ cat test.cpp
> >>>> #include "Test.h"
> >>>> jason$ clang++ -fsyntax-only test.cpp
> >>>> test.cpp:1:10: warning: include case does not match the case of the
> file on disk
> >>>> #include "Test.h"
> >>>>      ^
> >>>> 1 warning generated.
> >>>>
> >>>> What do you think? Is this desirable? Does the direction look right?
> >>>>
> >>>> Jason
> >>>>
> >>>> <include_case.diff>_______________________________________________
> >>>> cfe-dev mailing list
> >>>> cfe-dev at cs.uiuc.edu
> >>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
> >>>
> >>
> >
>
>
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