[patch/rfc,rfa:ppc64] Add osabi wildcard support
Andrew Cagney
ac131313@redhat.com
Thu Oct 23 23:25:00 GMT 2003
Hello,
The attached patch adds the ability to specify a wildcard machine when
registering an OSABI / arch / machine. It then updates PPC64 GNU/Linux
to specify that wild card (-1) instead of zero as the default machine.
Looking at the PPC64 GNU/Linux code:
gdbarch_register_osabi (bfd_arch_powerpc, 0, GDB_OSABI_LINUX,
ppc_linux_init_abi);
I believe that the call is attempting to register ppc_linux_init_abi as
the OSABI handler for all arch/machine conbinations. The problem is
that machine "0" gets turned into bfd_mach_ppc or bfd_mach_ppc64
dependant on how GDB is built, and they are both incompatible with each
other and incompatible . And that in turn restricts the support to just
one half of the ISA family making it impossible for GDB to debug both 32
and 64 bit :-(
I know of two ways to fix this. First is the attached patch which
modifies osabi.[hc] so that a wildcard machine (-1) can be specified vis:
gdbarch_register_osabi (bfd_arch_powerpc, -1, GDB_OSABI_LINUX,
ppc_linux_init_abi);
and the second is to explicitly register both of these architecture
variants vis:
gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc, ...
gdbarch_register_osabi (bfd_arch_powerpc, bfd_mach_ppc64, ...
(possibly also splitting ppc_linux_init_abi into ppc_linux_init_abi_32
and ppc_linux_init_abi_32).
There are pros and cons to both.
The former will always match, making the code somewhat future proof, the
later is far simplier.
preferences?
Andrew
PS: I'm also wondering if the existing ppc arch/machine table is
complete. I think it will indicate that e500 is "compatible" with "ppc"
when it is not.
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