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From:   Ian Rogers <irogers@google.com>
Date:   Thu, 12 Jan 2023 09:41:31 -0800
Message-ID: <CAP-5=fUmJutjku92vn_6OxLJZKJ60yhkS_XLbL7C7p_ska+xZw@mail.gmail.com>
Subject: Re: [PATCH v3 0/3] objtool build improvements
To:     Josh Poimboeuf <jpoimboe@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev
Cc:     Stephane Eranian <eranian@google.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Jiri Olsa <jolsa@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>
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On Thu, Jan 5, 2023 at 1:02 AM Ian Rogers <irogers@google.com> wrote:
>
> Install libsubcmd and then get headers from there, this avoids
> inadvertent dependencies on things in tools/lib. Fix V=1
> support. Clean up how HOSTCC is used to override CC to avoid CFLAGS
> being set for say gcc, and then CC being overridden to clang. Support
> HOSTCFLAGS as a make option.
>
> v3. Is a rebase that removes the merged "tools lib subcmd: Add install
>     target" patch. In:
> https://lore.kernel.org/lkml/CAKwvOd=kgXmpfbVa1wiEvwL0tX3gu+dDTGi-HEiRXSojwCLRrg@mail.gmail.com/
>     Nick rightly points out that:
> WARNINGS := $(EXTRA_WARNINGS) -Wno-switch-default -Wno-switch-enum -Wno-packed -Wno-nested-externs
>     became:
> WARNINGS := -Wno-switch-default -Wno-switch-enum -Wno-packed -Wno-nested-externs
>     losing the EXTRA_WARNINGS which v3 now adds back in. Previous
>     testing had added the warnings to the end rather than the
>     beginning, thereby causing unexpected build issues that aren't present in v3.
> v2. Include required "tools lib subcmd: Add install target" that is
>     already in Arnaldo's tree:
> https://lore.kernel.org/lkml/20221109184914.1357295-3-irogers@google.com/
> https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=630ae80ea1dd253609cb50cff87f3248f901aca3
>     When building libsubcmd.a from objtool's Makefile, clear the
>     subdir to avoid it being appended onto OUTPUT and breaking the
>     build.
>
> Ian Rogers (3):
>   objtool: Install libsubcmd in build
>   objtool: Properly support make V=1
>   objtool: Alter how HOSTCC is forced
>
>  tools/objtool/Build    |  2 --
>  tools/objtool/Makefile | 66 ++++++++++++++++++++++++++++++------------
>  2 files changed, 47 insertions(+), 21 deletions(-)

Ping. Relatively small set of patches, with Reviewed-by and Tested-by,
would be nice to land. Thanks!

Ian

> --
> 2.39.0.314.g84b9a713c41-goog
>