[rfa/Ada] Remove builtin_type_void

["Ulrich Weigand" <uweigand@de.ibm.com>]

Hello Joel,

this patch removes references to builtin_type_void from Ada code.

The only nontrivial case is the use in ada_resolve_function.  This routine
is called with "context_type" either NULL or a void type on input.  It
implements a two-phase search, where in the first phase it accepts all
routine with matching return type:

   If CONTEXT_TYPE is non-null and there is at least one match
   that returns that type, then eliminate matches that don't.  If
   CONTEXT_TYPE is void and there is at least one match that does not
   return void, eliminate all matches that do.

If no match is found during the first phase, it performs a second
phase with an "inverted" value of context_type: if it was a void type,
it becomes NULL, and if it was NULL, it becomes builtin_type_void.

My patch simplifies this by having the second phase simply accept
*all* matches.  There is no need to "invert" context_type -- we
already know that there are no matches for context_type, so any
remaining match is OK to return.

Tested on amd64-linux.  OK for mainline?

Bye,
Ulrich


ChangeLog:

	* ada-lang.c (resolve): Use per-architecture void type instead
	of platform-independent one.
	(ada_evaluate_subexp) [STRUCTOP_STRUCT]: Likewise.
	(ada_resolve_function): Reimplement fallback logic to avoid
	explicit reference to builtin_type_void.

Index: gdb-head/gdb/ada-lang.c
===================================================================
--- gdb-head.orig/gdb/ada-lang.c
+++ gdb-head/gdb/ada-lang.c
@@ -2583,9 +2583,13 @@ ada_decoded_op_name (enum exp_opcode op)
 static void
 resolve (struct expression **expp, int void_context_p)
 {
-  int pc;
-  pc = 0;
-  resolve_subexp (expp, &pc, 1, void_context_p ? builtin_type_void : NULL);
+  struct type *context_type = NULL;
+  int pc = 0;
+
+  if (void_context_p)
+    context_type = builtin_type ((*expp)->gdbarch)->builtin_void;
+
+  resolve_subexp (expp, &pc, 1, context_type);
 }
 
 /* Resolve the operator of the subexpression beginning at
@@ -3091,35 +3095,27 @@ ada_resolve_function (struct ada_symbol_
                       int nsyms, struct value **args, int nargs,
                       const char *name, struct type *context_type)
 {
+  int fallback;
   int k;
   int m;                        /* Number of hits */
-  struct type *fallback;
-  struct type *return_type;
-
-  return_type = context_type;
-  if (context_type == NULL)
-    fallback = builtin_type_void;
-  else
-    fallback = NULL;
 
   m = 0;
-  while (1)
+  /* In the first pass of the loop, we only accept functions matching
+     context_type.  If none are found, we add a second pass of the loop
+     where every function is accepted.  */
+  for (fallback = 0; m == 0 && fallback < 2; fallback++)
     {
       for (k = 0; k < nsyms; k += 1)
         {
           struct type *type = ada_check_typedef (SYMBOL_TYPE (syms[k].sym));
 
           if (ada_args_match (syms[k].sym, args, nargs)
-              && return_match (type, return_type))
+              && (fallback || return_match (type, context_type)))
             {
               syms[m] = syms[k];
               m += 1;
             }
         }
-      if (m > 0 || return_type == fallback)
-        break;
-      else
-        return_type = fallback;
     }
 
   if (m == 0)
@@ -9372,7 +9368,8 @@ ada_evaluate_subexp (struct type *expect
                    in some extension of the type.  Return an object of 
                    "type" void, which will match any formal 
                    (see ada_type_match). */
-                return value_zero (builtin_type_void, lval_memory);
+                return value_zero (builtin_type (exp->gdbarch)->builtin_void,
+				   lval_memory);
             }
           else
             type =
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com