two gdb porting questions

two gdb porting questions

[Jan Hoogerbrugge]

Dear all,

I am porting gdb to a new target and I can use some help. I am having
the following questions:

* How to find out whether there is a symbol at a memory address in
  opcodes/xxx-dis.c? Info->symbol_at_address_func does not work. It
  returns always 1.

* I want to use stabs to pass frame information from my compiler to
  gdb. Which stab number(s) should I use for this? How do I get this
  information in my xxx-tdep.c given the start address of the
  function? (I use ELF in the case that matters)

Thanks!
Jan




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Re: two gdb porting questions

[Daniel Jacobowitz]

On Fri, Jan 24, 2003 at 03:18:13PM +0100, Jan Hoogerbrugge wrote:
> Dear all,
> 
> I am porting gdb to a new target and I can use some help. I am having
> the following questions:
> 
> * How to find out whether there is a symbol at a memory address in
>  opcodes/xxx-dis.c? Info->symbol_at_address_func does not work. It
>  returns always 1.
> 
> * I want to use stabs to pass frame information from my compiler to
>  gdb. Which stab number(s) should I use for this? How do I get this
>  information in my xxx-tdep.c given the start address of the
>  function? (I use ELF in the case that matters)

Is it absolutely necessary that you use stabs?  There are clean ways to
express this information in DWARF-2, and if you're using ELF, there's
really no excuse.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: two gdb porting questions

[Jan Hoogerbrugge]

>From: Daniel Jacobowitz <drow@mvista.com>

> > * I want to use stabs to pass frame information from my compiler to
> >  gdb. Which stab number(s) should I use for this? How do I get this
> >  information in my xxx-tdep.c given the start address of the
> >  function? (I use ELF in the case that matters)
>
>Is it absolutely necessary that you use stabs?  There are clean ways to
>express this information in DWARF-2, and if you're using ELF, there's
>really no excuse.

My compiler (which is not gcc) happens to generate stabs. So I have to do it 
with stabs. Currently the compiler misuses a N_ROSYM to pass frame info to 
its debugger. However, gdb does not like this.

Are there other targets where a stab is used for frame information?

The instruction format of the debug target is so complex that decoding the 
prologue is not a real option.

Cheers,
Jan

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Re: two gdb porting questions

[Daniel Jacobowitz]

On Sun, Jan 26, 2003 at 11:50:55AM +0100, Jan Hoogerbrugge wrote:
> >From: Daniel Jacobowitz <drow@mvista.com>
> 
> >> * I want to use stabs to pass frame information from my compiler to
> >>  gdb. Which stab number(s) should I use for this? How do I get this
> >>  information in my xxx-tdep.c given the start address of the
> >>  function? (I use ELF in the case that matters)
> >
> >Is it absolutely necessary that you use stabs?  There are clean ways to
> >express this information in DWARF-2, and if you're using ELF, there's
> >really no excuse.
> 
> My compiler (which is not gcc) happens to generate stabs. So I have to do 
> it with stabs. Currently the compiler misuses a N_ROSYM to pass frame info 
> to its debugger. However, gdb does not like this.
> 
> Are there other targets where a stab is used for frame information?
> 
> The instruction format of the debug target is so complex that decoding the 
> prologue is not a real option.

We did something similar for an unpublished port; as a local hack it
wasn't too bad and we did it just about the same way you're describing. 
You just stuff the value in a new field in the symbol struct.

Eventually we arranged to generate DWARF-2 instead, though, and it went
away.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer