Re: bug#13342: [PARTIALLY SOLVED] bug#13342: Errors trying to build Guile 2.0.7

[Mark H Weaver]

Hi Peter,

Peter Teeson <address@hidden> writes:
> Many thanks for your reply. A nice demo but, no disrespect, maybe not
> really the issue.

With all due respect, I think that Ludovic discovered the root of the
problem, and that you're on the wrong track.  However, I've reached a
different conclusion than Ludovic about where the fault lies, based on
my different interpretation of the x86-64 ABI.

I've replied to the original bug report with my analysis of the problem:

  http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13342#32

In brief, the problem is an incompatibility between libffi and Clang,
because they have interpreted the x86-64 ABI requirements differently.
Specifically, libffi ZERO-extends arguments passed in registers when
calling foreign functions on x86-64 platforms, and Clang assumes that
the caller will SIGN-extend the arguments.

     Regards,
       Mark