regno_reg_rtx and related macros

[llewelly@198.dsl.xmission.com]

Does gdb provide support for macro expansions?

My (admittedly cursory) search through info gdb did not reveal hints about
  gdb support for debugging cpp macros, nor did my attempt to debug a test
  case compiled with -ggdb3 .

If gdb does provide features for debugging macros, I would appreciate
  knowing  how to make use of them.

On Sat, 18 Dec 1999, David S. Miller wrote:

>    Date: Sat, 18 Dec 99 20:38:39 EST
>    From: kenner@vlsi1.ultra.nyu.edu (Richard Kenner)
> 
>        That's a difference.  Dare I suggest fixing GDB?
> 
>        I see this as a deficiency in the debugger, 
> 
>    How?  The debugger never sees the macros and it would be unrealistic to
>    have it to macro expansions even if it did.
> 
> So unrealistic that gcc even has a documented option which is supposed
> to provide such information for a debugger:
> 
> `-gLEVEL'
> 
>  ...
> 
>      Level 3 includes extra information, such as all the macro
>      definitions present in the program.  Some debuggers support macro
>      expansion when you use `-g3'.
> 
> Later,
> David S. Miller
> davem@redhat.com
>