Re: Debug format problem with -ggdb flag

[Ralf Baechle <ralf@oss.sgi.com>]

On Wed, May 02, 2001 at 04:31:03PM -0700, Ian Thompson wrote:

> I'm running into problems with the debug information that is generated
> by the kernel compilation process.  Basically, I'm seeing that 
> multiple function symbols have the same begin address in the .mdebug
> section.  For example -- the init_arch and r3081_wait functions in my
> build have differnet addresses as far as compilation is concerned, and
> code executes correctly.  When I look into the .mdebug section, I see 
> that the begin, end, stab, and external records are all correct for 
> the r3081_wait function, but that the begin record for the init_arch
> function is the same as that for the the r3081_wait function!  This in
> turn seems to be causing the stab and external records to be incorrect,
> causing symbolic problems in my debugger.  
> 
> I've traced the problem down, and it seems to be a side-effect of 
> partial linking.  When the linker links multiple .o files into another
> .o file (which is later used as input to another ld command), the 
> debug records inside the .mdebug section are getting corrupted.  Has
> anyone run into this problem before?  Any suggestions of other flags
> I can pass into the partial link that may help?  I'm using the mipsel
> rpm of binutils 2.9.5-3.  Or, are there any alternatives to 
> partial linking that don't involve a lot of makefile manipulation?
> 
> I've tried using the -gcoff option to remove the stab records, but that
> option does not allow the 2.4 kernel to compile under egcs 2.91.66.

So then is a binutils and not a compiler problem.  What binutils are you
using?  Binutils 2.8.1 which I'm still recommending (mostly to avoid
sending people into a maze of version dependencies) is getting dated and
the bug may well have been fixed in the meantime.

  Ralf