Re: [RFA] Rewrite mips_get_saved_register()

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

> This patch depends on the following (as of yet) unapproved patches:
> 
>     http://sources.redhat.com/ml/gdb-patches/2002-08/msg00189.html
>     http://sources.redhat.com/ml/gdb-patches/2002-08/msg00195.html
>     http://sources.redhat.com/ml/gdb-patches/2002-08/msg00196.html
> 
> Okay to commit?
> 
> 	* mips-tdep.c (mips_get_saved_register): Rewrite to use
> 	frame_register_unwind() instead of find_saved_register().

Sorry, not like this.  Can you please, for the moment, just in-line the 
call to find_saved_register().

(The two other bugs you fixed were definitly needed and thanks for 
finding them.  How the code got away with not setting the SP I don't know.)

-      if (raw_buffer != NULL)
- 
{
- 
   LONGEST val;
- 
   if (regnum < 32)
- 
     /* Only MIPS_SAVED_REGSIZE bytes of GP registers are
-               saved. */
- 
     val = read_memory_integer (addr, MIPS_SAVED_REGSIZE);
- 
   else
- 
     val = read_memory_integer (addr, REGISTER_RAW_SIZE (regnum));
- 
   store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), val);
- 
}

In theory (and emphasis on the theory) things need to be changed so that:

- 32 32 bit nameless pseudo-registers are added to the cooked register space
- the 32 64 bit gprs get given a 64 bit virtual type so that they have 
identical raw and virtual sizes
- The debug info, for a 32 bit ABI, maps the gpr register numbers onto 
the 32 bit pseudo register range
- The gdbarch pseudo register read/write function maps the 32 bit 
pseudo-registers onto the 64 bit gprs.
- For init saved regs, dependant on the size of the register saved, 
either the the address of the 64 bit GPR or the address of the 32 bit 
pseudo-register is set
- a custom mips register unwind function maps the requested register (64 
bit gpr or 32 bit pseudo) onto: the 32 bit pseudo, the 64 bit gpr, or a 
further recursive unwind call.  If it has to do a 32/64 mapping then it 
sets not-an-lval.
- you find you have to yank all sorts of register converible code

But like I said, it is theory, the mips suffers from one hack (like the 
above) piled on top of another (the register convertable stuff, the 
register raw/virtual size being different, ...).  I don't know if now is 
the time to be experimenting with theories :-)

Andrew