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From:   Tri Vo <trong@android.com>
Date:   Mon, 14 Jan 2019 13:53:16 -0800
Message-ID: <CANA+-vDLJAHFLZADBM_2JhRy5-OR1tsLCJRqk-7mUfFxNO8dEw@mail.gmail.com>
Subject: Re: [PATCH 0/4] gcov: add Clang support
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     oberpar@linux.ibm.com, Greg Hackmann <ghackmann@android.com>,
        LKML <linux-kernel@vger.kernel.org>, kernel-team@android.com
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On Mon, Jan 14, 2019 at 1:33 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Mon, Jan 14, 2019 at 1:04 PM Tri Vo <trong@android.com> wrote:
> >
> > This patch series adds Clang supoprt for gcov.
> >
> > Patch 1 refactors existing code in preparation for Clang support. Patches
> > 2-3 implement necessary LLVM runtime hooks and gcov kernel interfaces.
> > Patch 4 simplifies config selection.
> >
> > Greg Hackmann (2):
> >   gcov: clang: move common gcc code into gcc_base.c
> >   gcov: clang support
> >
> > Nick Desaulniers (1):
> >   gcov: clang: link/unlink profiling data set.
> >
> > Tri Vo (1):
> >   gcov: clang: pick GCC vs Clang format depending on compiler
>
> Thanks for sending Tri!  Doesn't the output format require llvm-cov, or no?

Yes, .gcda files generated by a Clang-built kernel could only be
parsed by llvm-cov, but not gcc gcov (at least in my local tests).

llvm-cov documentation also indicates that GCC and LLVM gcov tools are
not necessarily compatible. "[llvm-cov] is compatible with the gcov
tool from version 4.2 of GCC and may also be compatible with some
later versions of gcov."
https://llvm.org/docs/CommandGuide/llvm-cov.html