remove param "dispp" from ada-lang.c::ada_lookup_struct_elt_type

The function is always called with DISPP set to NULL, so there is
no need for this parameter anymore. This patch removes it, and
eliminates some dead code associated to that.

gdb/ChangeLog:

        * ada-lang.c (ada_lookup_struct_elt_type): Remove parameter "dispp".
        Update all callers accordingly. Remove all code blocks handling
        the case where DISPP is not NULL.

Tested on x86_64-linux, no regression.

gdb/ChangeLog

@@ -1,3 +1,9 @@
+2017-08-25  Joel Brobecker  <brobecker@adacore.com>
+
+	* ada-lang.c (ada_lookup_struct_elt_type): Remove parameter "dispp".
+	Update all callers accordingly. Remove all code blocks handling
+	the case where DISPP is not NULL.
+
 2017-08-24  Jan Kratochvil  <jan.kratochvil@redhat.com>
 
 	PR symtab/22003

gdb/ada-lang.c

@@ -152,7 +152,7 @@ static struct symbol *find_old_style_renaming_symbol (const char *,
 						      const struct block *);
 
 static struct type *ada_lookup_struct_elt_type (struct type *, const char *,
-                                                int, int, int *);
+                                                int, int);
 
 static struct value *evaluate_subexp_type (struct expression *, int *);
 
@@ -6695,7 +6695,7 @@ ada_is_ignored_field (struct type *type, int field_num)
 int
 ada_is_tagged_type (struct type *type, int refok)
 {
-  return (ada_lookup_struct_elt_type (type, "_tag", refok, 1, NULL) != NULL);
+  return (ada_lookup_struct_elt_type (type, "_tag", refok, 1) != NULL);
 }
 
 /* True iff TYPE represents the type of X'Tag */
@@ -6721,7 +6721,7 @@ ada_is_tag_type (struct type *type)
 struct type *
 ada_tag_type (struct value *val)
 {
-  return ada_lookup_struct_elt_type (value_type (val), "_tag", 1, 0, NULL);
+  return ada_lookup_struct_elt_type (value_type (val), "_tag", 1, 0);
 }
 
 /* Return 1 if TAG follows the old scheme for Ada tags (used for Ada 95,
@@ -7066,7 +7066,7 @@ ada_variant_discrim_type (struct type *var_type, struct type *outer_type)
 {
   const char *name = ada_variant_discrim_name (var_type);
 
-  return ada_lookup_struct_elt_type (outer_type, name, 1, 1, NULL);
+  return ada_lookup_struct_elt_type (outer_type, name, 1, 1);
 }
 
 /* Assuming that TYPE is the type of a variant wrapper, and FIELD_NUM is a
@@ -7597,7 +7597,7 @@ type_as_string (struct type *type)
 
 static struct type *
 ada_lookup_struct_elt_type (struct type *type, const char *name, int refok,
-                            int noerr, int *dispp)
+                            int noerr)
 {
   int i;
 
@@ -7631,30 +7631,20 @@ ada_lookup_struct_elt_type (struct type *type, const char *name, int refok,
     {
       const char *t_field_name = TYPE_FIELD_NAME (type, i);
       struct type *t;
-      int disp;
 
       if (t_field_name == NULL)
         continue;
 
       else if (field_name_match (t_field_name, name))
-        {
-          if (dispp != NULL)
-            *dispp += TYPE_FIELD_BITPOS (type, i) / 8;
 	return TYPE_FIELD_TYPE (type, i);
-        }
 
       else if (ada_is_wrapper_field (type, i))
         {
-          disp = 0;
           t = ada_lookup_struct_elt_type (TYPE_FIELD_TYPE (type, i), name,
-                                          0, 1, &disp);
+                                          0, 1);
           if (t != NULL)
-            {
-              if (dispp != NULL)
-                *dispp += disp + TYPE_FIELD_BITPOS (type, i) / 8;
 	    return t;
         }
-        }
 
       else if (ada_is_variant_part (type, i))
         {
@@ -7669,23 +7659,19 @@ ada_lookup_struct_elt_type (struct type *type, const char *name, int refok,
 		 generates these for unchecked variant types.  Revisit
 	         if the compiler changes this practice.  */
 	      const char *v_field_name = TYPE_FIELD_NAME (field_type, j);
-              disp = 0;
+
 	      if (v_field_name != NULL 
 		  && field_name_match (v_field_name, name))
 		t = TYPE_FIELD_TYPE (field_type, j);
 	      else
 		t = ada_lookup_struct_elt_type (TYPE_FIELD_TYPE (field_type,
 								 j),
-						name, 0, 1, &disp);
+						name, 0, 1);
 
               if (t != NULL)
-                {
-                  if (dispp != NULL)
-                    *dispp += disp + TYPE_FIELD_BITPOS (type, i) / 8;
 		return t;
             }
         }
-        }
 
     }
 
@@ -7711,8 +7697,7 @@ is_unchecked_variant (struct type *var_type, struct type *outer_type)
 {
   const char *discrim_name = ada_variant_discrim_name (var_type);
 
-  return (ada_lookup_struct_elt_type (outer_type, discrim_name, 0, 1, NULL) 
+  return (ada_lookup_struct_elt_type (outer_type, discrim_name, 0, 1) == NULL);
-	  == NULL);
 }
 
 
@@ -11372,7 +11357,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
             {
               type = ada_lookup_struct_elt_type (type1,
                                                  &exp->elts[pc + 2].string,
-                                                 1, 1, NULL);
+                                                 1, 1);
 
 	      /* If the field is not found, check if it exists in the
 		 extension of this object's type. This means that we
@@ -11392,7 +11377,7 @@ ada_evaluate_subexp (struct type *expect_type, struct expression *exp,
           else
             type =
               ada_lookup_struct_elt_type (type1, &exp->elts[pc + 2].string, 1,
-                                          0, NULL);
+                                          0);
 
           return value_zero (ada_aligned_type (type), lval_memory);
         }