A long-overdue update of the ia64 code has been made.  It contains a number of 
changes worked on by myself and David Mosberger that were only in Red Hat's ia64 
gdb.  The testsuite results in 23 less failures (127 down to 104).  Most 
importantly, backtracing via libunwind is much improved, including vsyscall 
support, threaded backtraces, and stopping backtraces.

2005-06-08  Jeff Johnston  <jjohnstn@redhat.com>
             David Mosberger <davidm@hpl.hp.com>

         * ia64-tdep.c (KERNEL_START): New macro.
         (ia64_pseudo_register_read): Fix code to use libunwind to properly
         get the rse registers.
         (ia64_frame_this_id): Mark outermost frame with null frame id.
         (ia64_sigtramp_frame_prev_register): Fix up debug output.
         (ia64_access_rse_reg): New accessor function.
         (ia64_access_mem): Add special logic for accessing the
         kernel's unwind table.
         (getunwind_table): Fix for corefiles.
         (get_kernel_table): Fix to handle vDSO.
         (ia64_libunwind_frame_this_id): Check for null frame id and
         don't unwind past pc value of 0.  Fix debugging output.
         (ia64_libunwind_sigtramp_frame_this_id): New function.
         (ia64_libunwind_sigtramp_frame_prev_register): Ditto.
         (ia64_libunwind_sigtramp_frame_sniffer): Ditto.
         (ia64_libunwind_sigtramp_frame_unwind): New unwinder.
         (ia64_unw_rse_accessors): New libunwind accessors.
         (ia64_libunwind_descr): Add ia64_unw_rse_accessors.
         (ia64_gdbarch_init)[HAVE_LIBUNWIND_IA64_H]: Use
         ia64_libunwind_sigtramp_frame_sniffer instead of
         ia64_sigtramp_frame_sniffer.
         * libunwind-frame.c (libunwind_frame_set_descr): Add
         special register accessors.
         (libunwind_frame_cache): Add special logic to check for
         0 pc value.  Check for a signal trampoline frame.
         (libunwind_frame_this_id): Check if libunwind_frame_cache
         returns NULL.
         (libunwind_frame_prev_register): Check for NULL cache.
         (libunwind_frame_base_address): Ditto.
         (libunwind_sigtramp_frame_sniffer): New function.
         (libunwind_get_reg_special): Ditto.
         (libunwind_load): Add unw_is_signal_frame support.
         * libunwind-frame.h (struct libunwind_descr): Add special_accessors
         field.
         (libunwind_sigtramp_frame_sniffer): New prototype.
         (libunwind_get_reg_special): Ditto.