Date:   Thu, 9 Feb 2023 11:22:36 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     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+TJbNHT3jDF8wov@hirez.programming.kicks-ass.net>
References: <20230208171756.898991570@infradead.org>
 <Y+QEak2HWlkNuJ3U@fedora.fritz.box>
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On Wed, Feb 08, 2023 at 09:22:02PM +0100, Damian Tometzki wrote:
> 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));

Oh urgh. Apparently the kernel wrapper went missing in this userspace
project :-)

include/linux/build_bug.h:#define static_assert(expr, ...) __static_assert(expr, ##__VA_ARGS__, #expr)

Anyway, it's that last patch and I meant to do that in a slightly less
horrid way :-)