Re: [PATCH v2] Port GDB to Hurd x86_64.

John Baldwin
2024-02-27T23:15:46Z

On 2/23/24 9:28 PM, Flavio Cruz wrote:
> This port extends the existing i686 port to support x86_64 by trying to
> reuse existing code whenever it makes sense.
>
> * gdb/amd64-gnu-tdep.c: Adds logic for handling signal frames and
> position of amd64 registers in the different Hurd structs.
> The signal code is very similar to i686, except the trampoline code
> is adapted.
> * gdb/config/i386/nm-i386gnu.h: renamed to gdb/config/i386/nm-x86-gnu.h
> and adapt it for x86_64.
> * gdb/config/i386/i386gnu.mn: renamed to gdb/config/i386/nm-x86-gnu.mn
> and reuse it for x86_64.
> * gdb/configure.host: recognize gnu64 as a host.
> * gdb/configure.nat: recognize gnu64 host and update existing i386gnu to
> reuse the new shared files.
> * gdb/configure.tgt: recognize x86_64-*-gnu* triplet and use
> amd64-gnu-tdep.c.
> * gdb/i386-gnu-tdep.c: added i386_gnu_thread_state_reg_offset that is
> copied from i386-gnu-nat.c. This makes it similar to amd64.
> * gdb/i386-gnu-nat.c: rename it to x86-gnu-nat.c since we reuse this for
> i386 and amd64. Updated REG_ADDR to use one of the structures. Added
> VALID_REGISTER to make sure it's a register we can provide at this time
> (not all of them are available in amd64). FLAGS_REGISTER is either rfl
> or efl depending on the arch. Renamed functions and class from i386 to x86
> whenever they can be reused.
>
> Tested on Hurd x86_64 and i686.
> ---
>
> I addressed John's comments and moved amd64_gnu_thread_state_* and
> i386_gnu_thread_state_* to x86-gnu-nat.c. The new patch also contains a few
> changes that makes backtracing through shared libraries work.

Thanks, this generally looks ok to me.

One question I have is if you need nat/x86-xstate.o for the native Hurd x86_64
target? The i686 target doesn't use it and I didn't see any references in
the patches to XSAVE support, so I suspect you don't need it. Were you getting
a link error without it, or is it something you copied from Linux x86_64? If
the latter, it is probably best to drop it for now until you add XSAVE support
in the future (which would presumably apply to both i686 and x86_64).

Reviewed-By: John Baldwin <jhb@FreeBSD.org>

--
John Baldwin