Re: arm-elf message

[Joel Sherrill <joel dot sherrill at OARcorp dot com>]

Nick Clifton wrote:
> 
> Hi Joel,
> 
> : I am using arm-rtems which is arm-elf aliased to arm-rtems for
> : both binutils and gdb.  When I try to load the resulting
> : executable in the simulator in gdb, I get an error message
> : I assume is from the BFD.
> 
> Actually it is from gdb, specifically from
> dwarf2_build_psymtabs_hard() in gdb/dwarf2read.c.
> 
> : Dwarf Error: bad offset (0xb91c0) in compilation unit header (offset
> : 0x0 + 6).
> :
> : What does this message mean
> 
> I assume that you know what a compilation unit is.
> 
> It means that in the header describing the dwarf2 debug information
> for a particular compilation unit, the offset into the .debug.abbrev
> section is actually bigger than that section's size, (and hence must
> be wrong/corrupt).

Weird.. I was using a handcrafted linker script and it did not
have this section in it.  That must have confused gdb. 

Fixed now.  Thanks.

> :  and more importantly what is broken?
> 
> Well it sounds like the compilation unit header is corrupt.  These
> headers are usually the first data that occurs in the debugging
> sections, so it is possible that the headers have been overwritten by
> data from whichever section comes before the debug section ...
> 
> : I have forced some extra data in my .bss section and it turns out
> : that 0xb91c0 is the _end of the entire program image.
> 
> And by "forced" you mean what ?
> 
> This forcing, whatever it is, is probably the source of your
> problems.  I would begin my investigation there.
> 
> Cheers
>         Nick

-- 
Joel Sherrill, Ph.D.             Director of Research & Development
joel@OARcorp.com                 On-Line Applications Research
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