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From: Andrew Morton <akpm@linux-foundation•org>
To: Jim Davis <jim.epost@gmail•com>
Cc: Stephen Rothwell <sfr@canb•auug.org.au>,
	linux-next <linux-next@vger•kernel.org>,
	linux-kernel <linux-kernel@vger•kernel.org>,
	yalin.wang2010@gmail•com
Subject: Re: randconfig build error with next-20151009, in lib/zlib_deflate/deftree.c
Date: Mon, 12 Oct 2015 14:55:42 -0700	[thread overview]
Message-ID: <20151012145542.f1ea33ea2e5a0407b667a9e8@linux-foundation.org> (raw)
In-Reply-To: <CA+r1ZhiS661=BBD9fbeB9pkRyJUbGHCwcJ9SagpypaK_yp2WHA@mail.gmail.com>

On Fri, 9 Oct 2015 13:38:25 -0700 Jim Davis <jim.epost@gmail•com> wrote:

> Building with the attached random configuration file,
> 
> lib/built-in.o: In function `__bitrev32':
> deftree.c:(.text+0x1e799): undefined reference to `byte_rev_table'
> deftree.c:(.text+0x1e7a0): undefined reference to `byte_rev_table'
> deftree.c:(.text+0x1e7b4): undefined reference to `byte_rev_table'
> deftree.c:(.text+0x1e7c1): undefined reference to `byte_rev_table'

This is really irritating.  We save 287 bytes in kernels which don't
use bitrev.  It isn't worth the hassle, but let's keep plugging.



From: Andrew Morton <akpm@linux-foundation•org>
Subject: lib/Kconfig: ZLIB_DEFLATE must select BITREVERSE

lib/built-in.o: In function `__bitrev32':
deftree.c:(.text+0x1e799): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7a0): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7b4): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7c1): undefined reference to `byte_rev_table'

Anything which uses bitrevX() has to select BITREVERSE, to grab
lib/bitrev.o.

Reported-by: Jim Davis <jim.epost@gmail•com>
Signed-off-by: Andrew Morton <akpm@linux-foundation•org>
---

 lib/Kconfig |    1 +
 1 file changed, 1 insertion(+)

diff -puN lib/Kconfig~lib-kconfig-zlib_deflate-must-select-bitreverse lib/Kconfig
--- a/lib/Kconfig~lib-kconfig-zlib_deflate-must-select-bitreverse
+++ a/lib/Kconfig
@@ -220,6 +220,7 @@ config ZLIB_INFLATE
 
 config ZLIB_DEFLATE
 	tristate
+	select BITREVERSE
 
 config LZO_COMPRESS
 	tristate
_

      reply	other threads:[~2015-10-12 21:55 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-09 20:38 randconfig build error with next-20151009, in lib/zlib_deflate/deftree.c Jim Davis
2015-10-12 21:55 ` Andrew Morton [this message]

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