[cfe-dev] Fwd: Running Clang-Tidy on a Large Project

[Ahmad Nouralizadeh via cfe-dev]

Many Thanks! You helped me pinpoint the problem.
The problem is with the compile commands database. In fact, clang-tidy
expects the database format to be a little bit restricted (which is the
real cause of the problem). The input paths to build commands in MPlayer
are all relative (determined by the Makefile) as can be seen here:
...
            "-I/usr/local/lib/clang/3.9.0/include/",
            "-fpie",
            "-DPIC",
            "-D_REENTRANT",
            "-DZLIB_CONST",
            "-o",
            "libavformat/cafdec.o",
            "libavformat/cafdec.c"
        ],
        "directory": "/home/ahmad/Programs/MPlayer-1.3.0/ffmpeg",
        "file":
"/home/ahmad/Programs/MPlayer-1.3.0/ffmpeg/libavformat/cafdec.c"
...
This is part of the commands database generated using Bear with the file
entry revised to be absolute (I did that). The problem is still there.
Because the last two lines of the compile command arguments are relative
paths:
"libavformat/cafdec.o"
"libavformat/cafdec.c"
which should be changed to:
"/home/ahmad/Programs/MPlayer-1.3.0/ffmpeg/libavformat/cafdec.o"
"/home/ahmad/Programs/MPlayer-1.3.0/ffmpeg/libavformat/cafdec.c"
It seems that the fastest way to fix the problem is to postprocess the
commands database and make all paths absolute.


On Fri, Jul 20, 2018 at 11:53 AM, Miklos Vajna <vmiklos at vmiklos.hu> wrote:

> Hi,
>
> On Thu, Jul 19, 2018 at 11:04:21PM +0430, Ahmad Nouralizadeh <
> ahmadnouralizadeh at gmail.com> wrote:
> > path is recreated in that case. It can be seen at
> "clang-extra-tools-source/
> > clang-tidy/ClangTidy.cpp:line131" (clang-extra-tools-6.0.0):
> > ...
> >
> > SmallString<128> FixAbsoluteFilePath = Repl.getFilePath();
> >
> > Files.makeAbsolutePath(FixAbsoluteFilePath);
> > ...
> > But the same operation is not performed when the information is exported
> to
> > yaml, which is done when I run "run-clang-tidy" script with "-fix"
> option.
>
> Sounds like if you submit a patch to fix this, it would makes sense. (I
> haven't tried run-clang-tidy with -fix myself; what I usually do is
> invoking clang-tidy directly with -export-fixes=, then
> clang-apply-replacements, but in theory this is the same.)
>
> Perhaps the reason why nobody hit this before is the usage of relative
> paths; I think cmake just writes absolute paths in the compile commands
> db, so you don't hit the codepath where making the paths absolute
> matters.
>
> Regards,
>
> Miklos
>
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