[PATCH] Deal with GCC bug on 64-bit SPARC

[Mark Kettenis <kettenis@chello.nl>]

GCC generates code that doesn't conform to the ABI.  Fortunately, we
can deal with that lossage in GDB.  Patch attached and committed.

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>
 
	* sparc64-tdep.c (sparc64_store_floating_fields): If TYPE is a
	structure that has a single `float' member, store it in %f1 in
	addition to %f0.

 
Index: sparc64-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/sparc64-tdep.c,v
retrieving revision 1.5
diff -u -p -r1.5 sparc64-tdep.c
--- sparc64-tdep.c 3 Jan 2004 15:00:10 -0000 1.5
+++ sparc64-tdep.c 3 Jan 2004 20:44:44 -0000
@@ -668,6 +668,21 @@ sparc64_store_floating_fields (struct re
 	  sparc64_store_floating_fields (regcache, subtype, valbuf,
 					 element, subpos);
 	}
+
+      /* GCC has an interesting bug.  If TYPE is a structure that has
+         a single `float' member, GCC doesn't treat it as a structure
+         at all, but rather as an ordinary `float' argument.  This
+         argument will be stored in %f1, as required by the psABI.
+         However, as a member of a structure the psABI requires it to
+         be stored in.  To appease GCC, if a structure has only a
+         single `float' member, we store its value in %f1 too.  */
+      if (TYPE_NFIELDS (type) == 1)
+	{
+	  struct type *subtype = check_typedef (TYPE_FIELD_TYPE (type, 0));
+
+	  if (sparc64_floating_p (subtype) && TYPE_LENGTH (subtype) == 4)
+	    regcache_cooked_write (regcache, SPARC_F1_REGNUM, valbuf);
+	}
     }
 }