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Re: GCC 4.1: Buildable on GHz machines only?
On May 16, 2005, Russ Allbery <rra@stanford.edu> wrote:
> Alexandre Oliva <aoliva@redhat.com> writes:
>> On May 16, 2005, Russ Allbery <rra@stanford.edu> wrote:
>>> And package maintainers will never take cross-compilation seriously
>>> even if they really want to because they, for the most part, can't test
>>> it.
>> configure --build=i686-pc-linux-gnu \
>> --host=i686-somethingelse-linux-gnu
>> should be enough to exercise most of the cross-compilation issues, if
>> you're using a sufficiently recent version of autoconf, but I believe
>> you already knew that.
> What, you mean my lovingly hacked upon Autoconf 2.13 doesn't work?
No, just that it doesn't have the code that just compares build with
host to decide whether to enter cross-compilation mode. Unless you
back-ported that from autoconf 2.5x, that is.
> Seriously, though, I think the above only tests things out to the degree
> that Autoconf would already be warning about no default specified for
> cross-compiling, yes?
I believe so, yes. A configure script written with no regard to
cross-compilation may still fail to fail in catastrophic ways if
tested with native-cross.
> Wouldn't you have to at least cross-compile from a
> system with one endianness and int size to a system with a different
> endianness and int size and then try to run the resulting binaries to
> really see if the package would cross-compile?
Different endianness is indeed a harsh test on a package's
cross-compilation suitability. Simple reliance on size of certain
types can already get you enough breakage. Cross-building to x86 on
an x86_64 system may already catch a number of these.
> A scary number of packages, even ones that use Autoconf, bypass Autoconf
> completely when checking certain things or roll their own broken macros to
> do so.
+1
> I have never once gotten a single bug report, request, or report of
> anyone cross-compiling INN. Given that, it's hard to care except in
> some abstract cleanliness sense
But see, you do care, and you're aware of the issues, so it just
works. Unfortunately not all maintainers have as much knowledge or
even awareness about the subject as you do.
--
Alexandre Oliva http://www.ic.unicamp.br/~oliva/
Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org}