Change ada_which_variant_applies to value API

While debugging an Ada regression, I noticed that all the callers of
ada_which_variant_applies desconstruct a value, only to have it be
reconstructed by this function.

This patch removes this inefficiency in favor of simply passing in the
value directly.

Tested on x86-64 Fedora 30.

gdb/ChangeLog
2020-03-30  Tom Tromey  <tromey@adacore.com>

	* ada-valprint.c (print_variant_part): Update.
	* ada-lang.h (ada_which_variant_applies): Update.
	* ada-lang.c (ada_which_variant_applies): Remove outer_type and
	outer_valaddr parameters; replace with "outer" value parameter.
	(to_fixed_variant_branch_type): Update.

4 files changed, 13 insertions, 15 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 203d89c..af7e151 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,11 @@
+2020-03-30  Tom Tromey  <tromey@adacore.com>
+
+	* ada-valprint.c (print_variant_part): Update.
+	* ada-lang.h (ada_which_variant_applies): Update.
+	* ada-lang.c (ada_which_variant_applies): Remove outer_type and
+	outer_valaddr parameters; replace with "outer" value parameter.
+	(to_fixed_variant_branch_type): Update.
+
 2020-03-30  Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>
 
 	* ppc-linux-nat.c: Include <algorithm>, <unordered_map>, and
diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index 2822d40..565299a 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -7661,26 +7661,21 @@ is_unchecked_variant (struct type *var_type, struct type *outer_type)
 
 
 /* Assuming that VAR_TYPE is the type of a variant part of a record (a union),
-   within a value of type OUTER_TYPE that is stored in GDB at
-   OUTER_VALADDR, determine which variant clause (field number in VAR_TYPE,
+   within OUTER, determine which variant clause (field number in VAR_TYPE,
    numbering from 0) is applicable.  Returns -1 if none are.  */
 
 int
-ada_which_variant_applies (struct type *var_type, struct type *outer_type,
-                           const gdb_byte *outer_valaddr)
+ada_which_variant_applies (struct type *var_type, struct value *outer)
 {
   int others_clause;
   int i;
   const char *discrim_name = ada_variant_discrim_name (var_type);
-  struct value *outer;
   struct value *discrim;
   LONGEST discrim_val;
 
   /* Using plain value_from_contents_and_address here causes problems
      because we will end up trying to resolve a type that is currently
      being constructed.  */
-  outer = value_from_contents_and_address_unresolved (outer_type,
-						      outer_valaddr, 0);
   discrim = ada_value_struct_elt (outer, discrim_name, 1);
   if (discrim == NULL)
     return -1;
@@ -8555,9 +8550,7 @@ to_fixed_variant_branch_type (struct type *var_type0, const gdb_byte *valaddr,
 
   if (is_unchecked_variant (var_type, value_type (dval)))
       return var_type0;
-  which =
-    ada_which_variant_applies (var_type,
-                               value_type (dval), value_contents (dval));
+  which = ada_which_variant_applies (var_type, dval);
 
   if (which < 0)
     return empty_record (var_type);
diff --git a/gdb/ada-lang.h b/gdb/ada-lang.h
index 1f427b0..bb9e3c3 100644
--- a/gdb/ada-lang.h
+++ b/gdb/ada-lang.h
@@ -284,8 +284,7 @@ extern struct value *ada_delta (struct type *);
 
 extern struct value *ada_scaling_factor (struct type *);
 
-extern int ada_which_variant_applies (struct type *, struct type *,
-				      const gdb_byte *);
+extern int ada_which_variant_applies (struct type *, struct value *);
 
 extern struct type *ada_to_fixed_type (struct type *, const gdb_byte *,
 				       CORE_ADDR, struct value *,
diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c
index 59ada24..2f2375a 100644
--- a/gdb/ada-valprint.c
+++ b/gdb/ada-valprint.c
@@ -560,9 +560,7 @@ print_variant_part (struct value *value, int field_num,
 {
   struct type *type = value_type (value);
   struct type *var_type = TYPE_FIELD_TYPE (type, field_num);
-  int which = ada_which_variant_applies (var_type,
-					 value_type (outer_value),
-					 value_contents (outer_value));
+  int which = ada_which_variant_applies (var_type, outer_value);
 
   if (which < 0)
     return 0;