Re: [PATCH v3] Remove stale pre-AIX-7.2 compatibility guards

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

Simon Marchi <simon.marchi@polymtl.ca> wrote:
>On 9/22/26 12:52 AM, Aditya Vidyadhar Kamath wrote:
> >From: Aditya Kamath <Aditya.Kamath1@ibm.com>
> >
> >GDB now requires AIX 7.2 as the minimum supported version and will
> >support AIX 7.2 TL5, AIX 7.3 and upcoming AIX releases.  Remove
> >dead compatibility code that existed only for older releases.
> >
> >Remove the HAVE_DECL_GETTHRDS configure check since aix-thread.c was
> >the last
> >user of that macro.  Merge ptrace64aix and ptrace32 into a single
> >ptrace_aix function since they became identical after this
> >cleanup, and collapse all call sites that branched on arch64 just to
> >pick between the two.  Also clean up rs6000-aix-nat.c by removing
> >the
> >ARCH3264 and HAVE_PTRACE64 guards along with the ptracex fallback in
> >rs6000_ptrace32 and rs6000_ptrace64, which are now simple wrappers
> >around ptrace64.
> >
> >Also as per >https://www.ibm.com/docs/en/aix/7.2.0?topic=p-ptrace-
> ptracex-ptrace6>4-subroutine 
> >ptrace64 will also support 32-bit debugees.
>
>On this page I see:
>
>    For ptracex or ptrace64: If the debuggee is a 32-bit process, the
>    options that refer to GPRs or SPRs fail with errno = EIO
>
>And I see that in the patch, you call ptrace64 to read registers
>(PTT_READ_GPRS) for 32 bit processes.  How does that work?

I think Simon is correct here.  For GPRS access, I understand only
the following options are supported:

ptrace: 32- or 64-bit GDB, 32-bit inferior
ptracex: 32-bit GDB, 64-bit inferior
ptrace64: 64-bit GDB, 64-bit inferior

As I understand, the current set of indirections is intended to
cover that space - for a 32-bit inferior, you call ptrace, and
for a 64-bit inferior you call either ptracex or ptrace64,
depending on whether GDB is built as 64-bit.

Why do you think we can simplify this?  I guess we could make
possibly make the assumption that GDB itself is always built
as 64-bit these days, but then we still have to select between
ptrace and ptrace64 at the least ...

Bye,
Ulrich