Re: Cross-compilation from armhf to mips64el

[ludo@gnu.org (Ludovic Courtès)]

Andreas Enge <andreas@enge.fr> skribis:

> currently, we get lots of failed jobs for armhf coming from cross-compilation,
> such as
>    http://hydra.gnu.org/job/gnu/master/mips64el-linux-gnu.grep-2.21.armhf-linux

The problem in question is this:

--8<---------------cut here---------------start------------->8---
gcc   -D_RPC_THREAD_SAFE_ -D_GNU_SOURCE -DIS_IN_build -include /tmp/nix-build-glibc-cross-mips64el-linux-gnu-2.22.drv-0/build/config.h rpc_main.c \
	-o /tmp/nix-build-glibc-cross-mips64el-linux-gnu-2.22.drv-0/build/sunrpc/cross-rpc_main.o -MMD -MP -MF /tmp/nix-build-glibc-cross-mips64el-linux-gnu-2.22.drv-0/build/sunrpc/cross-rpc_main.o.dt -MT /tmp/nix-build-glibc-cross-mips64el-linux-gnu-2.22.drv-0/build/sunrpc/cross-rpc_main.o -c
In file included from /gnu/store/j3rpssxbamdarpqxsljxi9r28hl3zhzm-glibc-2.22/include/signal.h:326:0,
                 from /gnu/store/j3rpssxbamdarpqxsljxi9r28hl3zhzm-glibc-2.22/include/sys/param.h:28,
                 from rpc_main.c:45:
/gnu/store/j3rpssxbamdarpqxsljxi9r28hl3zhzm-glibc-2.22/include/sys/ucontext.h:107:16: error: field ?uc_mcontext? has incomplete type
     mcontext_t uc_mcontext;
                ^
Makefile:165: recipe for target '/tmp/nix-build-glibc-cross-mips64el-linux-gnu-2.22.drv-0/build/sunrpc/cross-rpc_main.o' failed
--8<---------------cut here---------------end--------------->8---

Before disabling cross-builds from armhf to mips64el like you suggest,
we should check whether the problem is on our side or note.

Here this is a cross-build of libc where we’re building a cross-rpcgen.
The cross-rpcgen is natively compiled, so GCC must have the native (arm)
kernel and libc headers in CPATH, not the mips headers.

I checked
/gnu/store/j3rpssxbamdarpqxsljxi9r28hl3zhzm-glibc-2.22/include/sys/ucontext.h
and I confirm that it’s an ARM header.

Long story short: everything is alright.  :-)

> I would think that the problem comes from build-aux/hydra/guix.scm, in this
> function:
>     (define (from-32-to-64? target)
>       ;; Return true if SYSTEM is 32-bit and TARGET is 64-bit.  This hack
>       ;; prevents known-to-fail cross-builds from i686-linux or armhf-linux to
>       ;; mips64el-linux-gnuabi64.
>       (and (or (string-prefix? "i686-" system)
>                (string-prefix? "armhf-" system))
>            (string-suffix? "64" target)))
> since target seems to be mips64el-linux-gnu and not mips64el-linux-gnuabi64.
> Then I would replace "string-suffix?" by "string-contains".

Or should we define a black list of pairs?

Ludo’.