Re: [PATCH 1/3] Clear non-significant bits of address on memory access

["Ulrich Weigand" <uweigand@de.ibm.com>]

Pedro Alves wrote:
> On 12/08/2017 10:04 AM, Yao Qi wrote:
> > --- a/gdb/aarch64-linux-tdep.c
> > +++ b/gdb/aarch64-linux-tdep.c
> > @@ -1217,6 +1217,8 @@ aarch64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
> >    set_xml_syscall_file_name (gdbarch, "syscalls/aarch64-linux.xml");
> >    set_gdbarch_get_syscall_number (gdbarch, aarch64_linux_get_syscall_number);
> >  
> > +  set_gdbarch_significant_addr_bit (gdbarch, 56);
> > +
> 
> I think adding the comment about "tag" here would be nice.
> 
>    The top bits of an address are known as the "tag" and are
>    ignored by the kernel, the hardware, etc. and can be regarded
>    as additional data associated with the address. */
>    set_gdbarch_significant_addr_bit (gdbarch, 56);
> 
> BTW, since this is ignored by the hardware, should it be done
> in aarch64-tdep.c instead of just for Linux?
> 
> Looks good to me otherwise.

This seems to duplicate the functionality of gdbarch_addr_bits_remove
to some extent ...  Could those be merged back again?

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com