Date:   Wed, 8 Feb 2023 21:22:02 +0100
From:   Damian Tometzki <dtometzki@fedoraproject.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     x86@kernel.org, jpoimboe@redhat.com, linux@weissschuh.net,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/10] objtool: Honey, I shrunk the instruction
Message-ID: <Y+QEak2HWlkNuJ3U@fedora.fritz.box>
Reply-To: Damian Tometzki <dtometzki@fedoraproject.org>
Mail-Followup-To: Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        jpoimboe@redhat.com, linux@weissschuh.net,
        linux-kernel@vger.kernel.org
References: <20230208171756.898991570@infradead.org>
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On Wed, 08. Feb 18:17, Peter Zijlstra wrote:
> Hi,
> 
> Boris complained he could no longer build allyesconfig on his 32G desktop
> machine without having OOM terminate either objtool or chrome.
> 
> After talking about these patches on IRC, Nathan mentioned the linux-clang CI
> was also having trouble of recent, and these patches appear to make it happy
> again.
> 
> In total these patches shrink an allyesconfig run by about 6G:
> 
> pre:	5:58.22 real,   226.69 user,    131.22 sys,     26221520 mem
> post:	5:03.34 real,   210.75 user,    88.80 sys,      20241232 mem
> 
> Also at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git/log/?h=objtool/core
> 
Hello Peter,

with clang-17 the build failed: 
In file included from weak.c:10:
In file included from /home/damian/kernel/linux/tools/objtool/include/objtool/objtool.h:13:
/home/damian/kernel/linux/tools/objtool/include/objtool/elf.h:88:86: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions]
static_assert(offsetof(struct reloc, rela.r_offset) == offsetof(struct reloc, offset));
                                                                                     ^
                                                                                     , ""
In file included from arch/x86/special.c:4:
In file included from /home/damian/kernel/linux/tools/objtool/include/objtool/special.h:10:
In file included from /home/damian/kernel/linux/tools/objtool/include/objtool/check.h:11/home/damian/kernel/linux/tools/objtool/include/objtool/elf.h:
In file included from :89:86: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions]
/home/damian/kernel/linux/tools/objtool/include/objtool/arch.h:11:
In file included from static_assert(offsetof(struct reloc, rela.r_addend) == offsetof(struct reloc, addend));
                                                                                     ^
                                                                                     , ""
/home/damian/kernel/linux/tools/objtool/include/objtool/objtool.h:13:
/home/damian/kernel/linux/tools/objtool/include/objtool/elf.h:88:86: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions]
static_assert(offsetof(struct reloc, rela.r_offset) == offsetof(struct reloc, offset));
                                                                                     ^
                                                                                     , ""
/home/damian/kernel/linux/tools/objtool/include/objtool/elf.h:89:86: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions]
static_assert(offsetof(struct reloc, rela.r_addend) == offsetof(struct reloc, addend));
                                                                                     ^
                                                                                     , ""
2 errors generated.
In file included from builtin-check.c:10:
In file included from /home/damian/kernel/linux/tools/objtool/include/objtool/objtool.h:13:
/home/damian/kernel/linux/tools/objtool/include/objtool/elf.h:88:86: error: '_Static_assert' with no message is a C2x extension [-Werror,-Wc2x-extensions]
static_assert(offsetof(struct reloc, rela.r_offset) == offsetof(struct reloc, offset));
...

Best regards
Damian