[ping] Re: [Patch] arch recognition fix for osabi.c

Kris Warkentin
2003-07-11T15:04:04Z

Mark, Daniel had suggested that you were the end of the line as far as
approving this change.

Thread starts here:
http://sources.redhat.com/ml/gdb-patches/2003-06/msg00562.html

cheers,

Kris

> On Tue, Jun 17, 2003 at 12:04:32PM -0400, Kris Warkentin wrote:
> > > This half I'm not convinced by. From our previous exchange I don't
> > > think you've fully justified it. Not approved without more
discussion.
> >
> > Okay. Let's use mips as an example. The 'compatible' check returns
true if
> > they have the same arch (ie. bfd_arch_mips). There will be many
different
> > values for the arch_info pointer, all with bfd_arch_mips and various
other
> > pieces of info such as which machine type (10k, 4300, etc.) of mips it
is.
> > The handler was registered for bfd_arch_mips with no other information.
In
> > the absence of the ABILITY to do anything smarter, we have to assume
that if
> > the handler is for bfd_arch_mips, it should be run.
> >
> > As it stands, if the bfd reads a file and says 'this is a tx3900' or
some
> > such, the pointers won't be the same and my backend init_abi won't be
run
> > even though I want it to run for all mips targets.
>
> All calls to gdbarch_register_osabi in GDB except for two use mach ==
> 0. The two are mips-linux-tdep.c, which appears to be solving the same
> problem - what a coincidence:
> for (arch_info = bfd_lookup_arch (bfd_arch_mips, 0);
> arch_info != NULL;
> arch_info = arch_info->next)
> {
> gdbarch_register_osabi (bfd_arch_mips, arch_info->mach,
GDB_OSABI_LINUX,
> mips_linux_init_abi);
> }
> and x86-64. For x86-64 your change is correct since BFD will catch the
> different bits-per-word and return NULL. For mips-linux-tdep it would
> let you remove that loop, which I have a vague memory of being annoyed
> at when it became necessary.
>
> The check came from
>
> 2002-12-14 Mark Kettenis <kettenis@gnu.org>
>
> * osabi.c: Include "gdb_assert.h" and "gdb_string.h".
> (struct gdb_osabi_handler): Remove member `arch'. Add member
> `arch_info'.
> (gdbarch_register_osabi): Add new argument `machine'. Use ot to
> construct a `struct bfd_arch_info' and store it in the `struct
> gdb_osabi_handler' that is created.
> (gdbarch_init_osabi): Check for compatibility based on machine
> type and architecture.
> * osabi.h (gdbarch_register_osabi): Adjust prototype and update
> comment.
>
> So I'm not going to approve it until Mark comments. Mark, Kris is
> suggesting that the "arch_info ==" in the ->compatible check should
> simply be a "NULL !=".
>
> > > > (generic_elf_osabi_sniff_abi_tag_sections): Add check for QNX
> > Neutrino
> > > > binaries.
> > >
> > > This bit looks fine, except for two things: you've missed the coding
> > > standards by four space characters (before left parens), and your
> > > "safety first" check overruns the buffer (missing +1 in the alloca).
> >
> > Doh! Not very safe was it? Sorry about that. Fixed.
> >
> > cheers,
> >
> > Kris
> >
> >
> >
>
> --
> Daniel Jacobowitz
> MontaVista Software Debian GNU/Linux Developer
>