Latest GCC fails to build glibc

[Florian Weimer]

On 05/14/2015 10:59 PM, Steve Ellcey  wrote:
> A recent change to GCC (Fix to PR middle-end/66110) has caused glibc to
> fail to build.  When compiling the latest glibc with the latest GCC I
> get the error below.  I don't know if this is a GCC problem or a glibc
> problem.  I notice that when Richard checked this in he also added the
> use of -Wno-strict-aliasing to the compilation of one of the GCC files.
> Maybe we need the same thing when compiling memstream.c?
> 
> Steve Ellcey
> sellcey@imgtec.com
> 
> 
> In file included from memstream.c:18:0:
> memstream.c: In function 'open_memstream':
> memstream.c:92:22: error: dereferencing type-punned pointer will break strict-aliasing rules [-Werror=strict-aliasing]
>    _IO_JUMPS ((struct _IO_FILE_plus *) &new_f->fp._sf._sbf) = &_IO_mem_jumps;

Steve, could you try the attached patch, please?

An alternative fix for some of these issues would be to use the
cast-free member access where the type of the outer object is known from
context, getting rid of _IO_JUMPS.

-- 
Florian Weimer / Red Hat Product Security
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