Use registry in gdbarch

gdbarch implements its own registry-like approach.  This patch changes
it to instead use registry.h.  It's a rather large patch but largely
uninteresting -- it's mostly a straightforward conversion from the old
approach to the new one.

The main benefit of this change is that it introduces type safety to
the gdbarch registry.  It also removes a bunch of code.

One possible drawback is that, previously, the gdbarch registry
differentiated between pre- and post-initialization setup.  This
doesn't seem very important to me, though.

1 files changed, 5 insertions, 5 deletions

diff --git a/gdb/ia64-libunwind-tdep.h b/gdb/ia64-libunwind-tdep.h
index 2484ea8..56425d0 100644
--- a/gdb/ia64-libunwind-tdep.h
+++ b/gdb/ia64-libunwind-tdep.h
@@ -40,11 +40,11 @@ struct frame_unwind;
 
 struct libunwind_descr
 {
-  int (*gdb2uw) (int);
-  int (*uw2gdb) (int);
-  int (*is_fpreg) (int);
-  void *accessors;
-  void *special_accessors;
+  int (*gdb2uw) (int) = nullptr;
+  int (*uw2gdb) (int) = nullptr;
+  int (*is_fpreg) (int) = nullptr;
+  void *accessors = nullptr;
+  void *special_accessors = nullptr;
 };
 
 int libunwind_frame_sniffer (const struct frame_unwind *self,