Re: [RFC] Adding --skip-mismatch option to ld

[Ian Lance Taylor <ian@airs.com>]

   Date: Tue, 8 Jun 1999 00:14:52 +0200
   From: Jakub Jelinek <jj@sunsite.ms.mff.cuni.cz>

   On Mon, Jun 07, 1999 at 12:05:30PM -0700, Richard Henderson wrote:
   > On Fri, Jun 04, 1999 at 05:12:07PM +0200, Jakub Jelinek wrote:
   > > Now Solaris linker apparently skips a library in the search path if it is
   > > for the wrong architecture (=emulation) which makes a lot of sense to me,
   > > that's why I wrote the second part of this patch. I've made it optional and
   > > not default because it differs from the standard library path searching, on
   > > the other side without this any compilation with some wrong arch library in
   > > the search path before the correct arch one would die in error.
   > 
   > I don't see any need to make this optional.  My preferred solution
   > would be to skip the library with a note written to the map file
   > to aid diagnosing user's problems.

   In such a case, what would it do if --no-warn-mismatch is specified?
   Should it stop skipping the libraries and choose the first one in the search
   path, or should it continue skipping incompatible libraries, in which case
   if the user wanted to link against an incompatible library, he'd have to
   specify its full name including path?

--no-warn-mismatch is more likely to be used for object files rather
than archives.  Even if we make --skip-mismatch the default behaviour,
I don't see any need to change the behaviour of --no-warn-mismatch.

So I would pick your second choice if --skip-mismatch were to become
the default.  However, requiring things like specifying the full
pathname is exactly why I think it would be unwise to make
--skip-mismatch the default.  It becomes harder to predict the
linker's behaviour.

   I don't know much about what are people using --no-warn-mismatch for and
   what tasks are they solving by it, so I cannot come to conclusion about the
   above question easily myself.

People use --no-warn-mismatch mainly for things like -mips2 vs. -mips3
object files.  C code compiled with -mips2 and -mips3 use different
calling conventions, so the linker prevents you from linking them
together.  However, in certain specific cases, such as when building a
kernel, it is desirable to link them together; the --no-warn-mismatch
option permits such cases.

Ian