Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 7 Jun 2019 08:32:46 -0700
From:   Tom Roeder <tmroeder@google.com>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Raul E Rangel <rrangel@chromium.org>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Matthias Kaehlcke <mka@chromium.org>, zwisler@chromium.org,
        Joe Lawrence <joe.lawrence@redhat.com>,
        Kees Cook <keescook@chromium.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Petr Mladek <pmladek@suse.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Changbin Du <changbin.du@intel.com>,
        Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Sri Krishna chowdary <schowdary@nvidia.com>,
        Matthew Wilcox <willy@infradead.org>,
        Mikulas Patocka <mpatocka@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH] kbuild: Add option to generate a Compilation Database
Message-ID: <20190607153246.GB101503@google.com>
References: <20190606203003.112040-1-rrangel@chromium.org>
 <20190606205406.GA120512@google.com>
 <CAKwvOd=RCL3hpHBVukomrRiXKhvJHMxe3HSrtd0MRcCe1B3ZGw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAKwvOd=RCL3hpHBVukomrRiXKhvJHMxe3HSrtd0MRcCe1B3ZGw@mail.gmail.com>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jun 06, 2019 at 04:40:00PM -0700, Nick Desaulniers wrote:
> On Thu, Jun 6, 2019 at 1:54 PM Tom Roeder <tmroeder@google.com> wrote:
> >
> > On Thu, Jun 06, 2019 at 02:30:03PM -0600, Raul E Rangel wrote:
> > > Clang tooling requires a compilation database to figure out the build
> > > options for each file. This enables tools like clang-tidy and
> > > clang-check.
> > >
> > > See https://clang.llvm.org/docs/HowToSetupToolingForLLVM.html for more
> > > information.
> 
> I'm also super happy to see this!
> https://nickdesaulniers.github.io/blog/2017/05/31/running-clang-tidy-on-the-linux-kernel/
> I don't know enough about GNU Make/Kbuild to answer the questions, but
> hopefully Masahiro can help there.
> 
> > I'm glad to see someone adding this to the Makefile directly. I added
> > scripts/gen_compile_commands.py in b302046 (in Dec 2018) when I was
> 
> Heh, cool.  I had a script that basically did this; we recently
> dropped it from the Android trees when doing an audit of out of tree
> patches.
> 
> > working on using clang-check to look for bugs in KVM. That script
> 
> I'm very interested in this work; my summer intern is looking into
> static analyses of the Linux kernel.  Can you maybe reach out to me
> off thread to tell me more about what you found (or didn't)?
> 
> > > Normally cmake is used to generate the compilation database, but the
> > > linux kernel uses make. Another option is using
> > > [BEAR](https://github.com/rizsotto/Bear) which instruments
> > > exec to find clang invocations and generate the database that way.
> 
> It's probably possible to get this to work w/ GCC if the additional
> dependency of bear exists on the host's system (and may reduce the
> number of implementations).  Downside is the additional host
> dependency.
> 
> Sounds like it may also be possible to just run
> scripts/gen_compile_commands.py at build time if this config is
> enabled?

Yes, for scripts/gen_compile_commands.py, you run a build first with
whatever configuration you want, then call the script to produce the
compile_commands.json file.