Re: [RFA/rfc] blockframe.c: dummy frames unwind and pseudoregs

[Andrew Cagney <ac131313@ges.redhat.com>]

> This is because the generic_call_dummy_register_unwind() doesn't deal with
> pseudo registers. It has this comment:
> 
>       /* Return the actual value.  */
>       /* FIXME: cagney/2002-06-26: This should be via the
>          gdbarch_register_read() method so that it, on the fly,
>          constructs either a raw or pseudo register from the raw
>          register cache.  */
>       regcache_raw_read (registers, regnum, bufferp);
> 
> 
> If instead of raw reads I do cooked reads, I don't get the error.  I
> wonder though if, based of the comment, this could be a problem for
> other targets.
> Thoughts?

Two architecture features could cause problems:
- where an architecture has different sized raw and virtual (pre-cursor 
to cooked) registers
- where there are pseudo registers

MIPS has has different sized raw and virtual registers and, suprise!, 
doesn't use the code in question.

That code block definitly needs to read the cooked value.  The only 
potential problem is with:
http://sources.redhat.com/ml/gdb/2002-08/msg00196.html
and there, I think your case adds support to the argument that the dummy 
frame code should save (readonly) cooked values.

Given this, yes, ok.

BTW, don't forget to update the comment :-)

Andrew



> 2002-08-22  Elena Zannoni  <ezannoni@redhat.com>
> 
> 	* blockframe.c (generic_call_dummy_register_unwind): Use
> 	regcache_cooked_read to catch cases in which the variable is
> 	stored in a pseudo register.
> 
> Index: blockframe.c
> ===================================================================
> RCS file: /cvs/uberbaum/gdb/blockframe.c,v
> retrieving revision 1.37
> diff -u -p -r1.37 blockframe.c
> --- blockframe.c	18 Aug 2002 22:40:15 -0000	1.37
> +++ blockframe.c	22 Aug 2002 15:35:27 -0000
> @@ -1406,7 +1406,7 @@ generic_call_dummy_register_unwind (stru
>           gdbarch_register_read() method so that it, on the fly,
>           constructs either a raw or pseudo register from the raw
>           register cache.  */
> -      regcache_raw_read (registers, regnum, bufferp);
> +      regcache_cooked_read (registers, regnum, bufferp);
>      }
>  }
>