Re: GDB make error: for m68xx toolchain

[Michael Snyder <msnyder at specifix dot com>]

On Fri, 2008-04-04 at 12:42 +1000, No.Spam wrote:
> Michael Snyder wrote:
> > On Fri, 2008-04-04 at 12:21 +1000, Nathan K wrote:
> >   
> >> Hi people who have more of an idea about this than me,
> >>
> >> For Uni we have to compile for the m68hc11. So I've set about setting up
> >> the toolchain so I can work at home as indicated here.
> >>
> >> My problem is a make error when compiling GDB
> >>
> >> make[1]: *** No rule to make target `-lm', needed by `gdb'. Stop.
> >> make: *** [all-gdb] Error 2
> >>
> >> I'm running os x, gcc 3.3.5 (using gcc_select), gdb-6.2 with 68hc patch as
> >> indicated on GCC 68HC11 & 68HC12 Sources Installation
> >>
> >> I think this might be referring to the math library, but I'm not sure what
> >> to do about it. perhaps add a config option or edit make file???
> >>
> >> Thanks in advance for any pointers,
> >>
> >> Nathan
> >>     
> >
> > What's Uni?  Oh, university?  Heh, you're not at an .edu address...
> >
> > Yes, the error message refers to the math library.
> > "-lm" means "link with libm.a" (or libm.so, depending).
> > But the -lm directive seems to be misplaced somehow, 
> > perhaps from your host/target makefile fragment.
> >
> > We're at version 6.8, though -- we can't help you too much
> > with version 6.2...
> >
> >
> >
> >   
> Thanks for your response, yeah I use a dumb email address for lists to 
> avoid spam.
> 
> Could I just go into the Makefile and add the flag? or is it a configure 
> option? Where would this directive normally be?
> 
> I'd be happy to change to 6.8 but since I'm using it for cross compiling 
> I need to ensure that it will work with the m68hc11.... also this is my 
> first experience setting up a toolchain, so I'm trying to be 
> conservative with what I try (since i'm not sure about what might work 
> and don't want to get in over my head).
> 
> If anyone know of a toolchain that works with a newer version of GDB 
> please let me know.

The version numbers (6.2 and 6.8) are gdb versions, not toolchain.
When people talk about a toolchain version, they're usually referring
to the gcc version number.  I don't think that's an issue here.
The issue is that gdb version 6.2 was a long time ago (2004, actually),
and the sources that we work with have changed a lot since then.  We
don't generally like to go back in time and help people work with
old versions of the sources -- the general practice is to say "update
to the latest release of gdb, then if you still have problems we'll
help you".

So not to go against precedent, but...

I see that in the source version you are using (6.2), there is a
file in the source tree, "gdb/config/m68hc11/m68hc11.mt" 

That file is called a "target makefile fragment", and it winds up
as part of your makefile.  And it contains a line that looks like this:

    SIM= ../sim/m68hc11/libsim.a -lm

There's your "-lm".

That means it is trying to link the math library (-lm == libm.a)
into the simulator library.

But rather than worry about fixing it or even why it's wrong, 
I'll just tell you that that file doesn't even exist in the 
current source tree, so your problem is likely to go away
(or at least change form) if you go to a more recent gdb version.

Good luck!