Jerone Young
2007-Jul-09 20:11 UTC
[Xen-devel] todays xen-unstable is throwing gcc errors when compiling on PPC
When compiling Xen on PPC today I get the following error that is being caused by casting (u32 *). Once the cast is removed all is well and things compile fine. Is this happening on x86 or x86-64 ? I''m using gcc 4.1.0 on Suse SLES 10. There Error: grant_table.c: In function ‘gnttab_prepare_for_transfer’: grant_table.c:825: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c: In function ‘__acquire_grant_for_copy’: grant_table.c:1055: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c:1080: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c:1080: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c:1080: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c:1080: warning: dereferencing type-punned pointer will break strict-aliasing rules grant_table.c:1080: warning: dereferencing type-punned pointer will break strict-aliasing rules make[3]: *** [grant_table.o] Error 1 make[3]: Leaving directory `/Work/xen-unstable.hg/xen/common'' make[2]: *** [/Work/xen-unstable.hg/xen/common/built_in.o] Error 2 make[2]: Leaving directory `/Work/xen-unstable.hg/xen/arch/powerpc'' make[1]: *** [/Work/xen-unstable.hg/xen/xen] Error 2 make[1]: Leaving directory `/Work/xen-unstable.hg/xen'' make: *** [build] Error 2 _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Keir Fraser
2007-Jul-09 21:23 UTC
Re: [Xen-devel] todays xen-unstable is throwing gcc errors when compiling on PPC
This problem is caused by my patch which moved the addition of
-fno-strict-aliasing to CFLAGS into Config.mk. At the same time I *removed*
-fno-strict-aliasing from arch/{x86,powerpc,ia64}/Rules.mk. My assumption
was that everyone would simply add to the CFLAGS created by Config.mk and
xen/Rules.mk, just to add arch-specific extras.
I see you do not do this because you have a ''CFLAGS :='' in
your
arch/powerpc/Rules.mk. So you need to do one of:
1. Get rid of the ''CFLAGS :='' and simply adapt the generic
CFLAGS.
2. Add CFLAGS += -fno-strict-aliasing back into your Rules.mk.
Unless there is a good reason to do otherwise, (1) is the way to go.
-- Keir
On 9/7/07 21:11, "Jerone Young" <jyoung5@us.ibm.com> wrote:
> When compiling Xen on PPC today I get the following error that is being
> caused by casting (u32 *). Once the cast is removed all is well and
> things compile fine. Is this happening on x86 or x86-64 ? I''m
using gcc
> 4.1.0 on Suse SLES 10.
>
> There Error:
> grant_table.c: In function gnttab_prepare_for_transfer¹:
> grant_table.c:825: warning: dereferencing type-punned pointer will break
> strict-aliasing rules
> grant_table.c: In function __acquire_grant_for_copy¹:
> grant_table.c:1055: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> grant_table.c:1080: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> grant_table.c:1080: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> grant_table.c:1080: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> grant_table.c:1080: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> grant_table.c:1080: warning: dereferencing type-punned pointer will
> break strict-aliasing rules
> make[3]: *** [grant_table.o] Error 1
> make[3]: Leaving directory `/Work/xen-unstable.hg/xen/common''
> make[2]: *** [/Work/xen-unstable.hg/xen/common/built_in.o] Error 2
> make[2]: Leaving directory
`/Work/xen-unstable.hg/xen/arch/powerpc''
> make[1]: *** [/Work/xen-unstable.hg/xen/xen] Error 2
> make[1]: Leaving directory `/Work/xen-unstable.hg/xen''
> make: *** [build] Error 2
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel