+ lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch added to -mm tree

+ lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch added to -mm tree

[akpm]

The patch titled
     Subject: lib/clz_tab.c: put in lib-y rather than obj-y
has been added to the -mm tree.  Its filename is
     lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch

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------------------------------------------------------
From: Chris Metcalf <cmetcalf@ezchip.com>
Subject: lib/clz_tab.c: put in lib-y rather than obj-y

The clz table (__clz_tab) in lib/clz_tab.c is also provided as part of
libgcc.a, and many architectures link against libgcc.  To allow the linker
to avoid a multiple-definition link failure, clz_tab.o has to be in
lib/lib.a rather than lib/builtin.o.  The specific issue is that libgcc.a
comes before lib/builtin.o on vmlinux.o's link command line, so its _clz.o
is pulled to satisfy __clz_tab, and then when the remainder of
lib/builtin.o is pulled in to satisfy all the other dependencies, the
__clz_tab symbols conflict.  By putting clz_tab.o in lib.a, the linker can
simply avoid pulling it into vmlinux.o when this situation arises.

The definitions of __clz_tab are the same in libgcc.a and in the kernel;
arguably we could also simply rename the kernel version, but it's unlikely
the libgcc version will ever change to become incompatible, so just using
it seems reasonably safe.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/Makefile |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN lib/Makefile~lib-clz_tabc-put-in-lib-y-rather-than-obj-y lib/Makefile
--- a/lib/Makefile~lib-clz_tabc-put-in-lib-y-rather-than-obj-y
+++ a/lib/Makefile
@@ -153,7 +153,7 @@ obj-$(CONFIG_GLOB) += glob.o
 obj-$(CONFIG_MPILIB) += mpi/
 obj-$(CONFIG_SIGNATURE) += digsig.o
 
-obj-$(CONFIG_CLZ_TAB) += clz_tab.o
+lib-$(CONFIG_CLZ_TAB) += clz_tab.o
 
 obj-$(CONFIG_DDR) += jedec_ddr_data.o
 
_

Patches currently in -mm which might be from cmetcalf@ezchip.com are

lib-clz_tabc-put-in-lib-y-rather-than-obj-y.patch