Re: [PATCH] mips-tdep.c: Fix bug in evaluating signed address

Daniel Jacobowitz
2006-07-12T19:31:57Z

On Fri, Jun 16, 2006 at 06:23:32PM +0200, Corinna Vinschen wrote:
> Hi,
>
> the below patch fixes the mips_integer_to_address function. What
> happens is this:
>
> If the incoming type is an *unsigned* value, then unpack_long takes the
> (un)signedness into account. This results in `val' not being signed
> extended, as the mips_integer_to_address function was originally
> designed for.
>
> So, to enforce correct signedness of the resulting address, I changed
> the unpack_long call to extract_signed_integer. This way, val is always
> sign extended and the mips address is correctly signed.

I might be missing something, but isn't the function mostly redundant
now?

> Index: gdb/mips-tdep.c
> ===================================================================
> RCS file: /cvs/cvsfiles/gnupro/gdb/mips-tdep.c,v
> retrieving revision 1.24
> diff -u -p -r1.24 mips-tdep.c
> --- gdb/mips-tdep.c 15 Jun 2006 08:57:17 -0000 1.24
> +++ gdb/mips-tdep.c 16 Jun 2006 16:15:48 -0000
> @@ -4749,7 +4749,7 @@ mips_integer_to_address (struct gdbarch
> struct type *type, const gdb_byte *buf)
> {
> gdb_byte *tmp = alloca (TYPE_LENGTH (builtin_type_void_data_ptr));
> - LONGEST val = unpack_long (type, buf);
> + LONGEST val = extract_signed_integer (buf, TYPE_LENGTH (type));
> store_signed_integer (tmp, TYPE_LENGTH (builtin_type_void_data_ptr), val);
> return extract_signed_integer (tmp,
> TYPE_LENGTH (builtin_type_void_data_ptr));

Those last two have got to be a no-op.

--
Daniel Jacobowitz
CodeSourcery