gdb: Convert enum range_type to a bit field enum

The expression range_type enum represents the following ideas:

  - Lower bound is set to default,
  - Upper bound is set to default,
  - Upper bound is exclusive.

There are currently 6 entries in the enum to represent the combination
of all those ideas.

In a future commit I'd like to add stride information to the range,
this could in theory appear with any of the existing enum entries, so
this would take us to 12 enum entries.

This feels like its getting a little out of hand, so in this commit I
switch the range_type enum over to being a flags style enum.  There's
one entry to represent no flags being set, then 3 flags to represent
the 3 ideas above.  Adding stride information will require adding only
one more enum flag.

I've then gone through and updated the code to handle this change.

There should be no user visible changes after this commit.

gdb/ChangeLog:

	* expprint.c (print_subexp_standard): Update to reflect changes to
	enum range_type.
	(dump_subexp_body_standard): Likewise.
	* expression.h (enum range_type): Convert to a bit field enum, and
	make the enum unsigned.
	* f-exp.y (subrange): Update to reflect changes to enum
	range_type.
	* f-lang.c (value_f90_subarray): Likewise.
	* parse.c (operator_length_standard): Likewise.
	* rust-exp.y (rust_parser::convert_ast_to_expression): Likewise.
	* rust-lang.c (rust_range): Likewise.
	(rust_compute_range): Likewise.
	(rust_subscript): Likewise.

1 files changed, 11 insertions, 14 deletions

diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index f7c762eb640..820ebb92c43 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -1077,13 +1077,11 @@ rust_range (struct expression *exp, int *pos, enum noside noside)
   kind = (enum range_type) longest_to_int (exp->elts[*pos + 1].longconst);
   *pos += 3;
 
-  if (kind == HIGH_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT
-      || kind == NONE_BOUND_DEFAULT_EXCLUSIVE)
+  if (!(kind & RANGE_LOW_BOUND_DEFAULT))
     low = evaluate_subexp (nullptr, exp, pos, noside);
-  if (kind == LOW_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT_EXCLUSIVE
-      || kind == NONE_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT_EXCLUSIVE)
+  if (!(kind & RANGE_HIGH_BOUND_DEFAULT))
     high = evaluate_subexp (nullptr, exp, pos, noside);
-  bool inclusive = (kind == NONE_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT);
+  bool inclusive = !(kind & RANGE_HIGH_BOUND_EXCLUSIVE);
 
   if (noside == EVAL_SKIP)
     return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
@@ -1166,13 +1164,13 @@ rust_range (struct expression *exp, int *pos, enum noside noside)
 static void
 rust_compute_range (struct type *type, struct value *range,
 		    LONGEST *low, LONGEST *high,
-		    enum range_type *kind)
+		    range_types *kind)
 {
   int i;
 
   *low = 0;
   *high = 0;
-  *kind = BOTH_BOUND_DEFAULT;
+  *kind = RANGE_LOW_BOUND_DEFAULT | RANGE_HIGH_BOUND_DEFAULT;
 
   if (type->num_fields () == 0)
     return;
@@ -1180,15 +1178,15 @@ rust_compute_range (struct type *type, struct value *range,
   i = 0;
   if (strcmp (TYPE_FIELD_NAME (type, 0), "start") == 0)
     {
-      *kind = HIGH_BOUND_DEFAULT;
+      *kind = RANGE_HIGH_BOUND_DEFAULT;
       *low = value_as_long (value_field (range, 0));
       ++i;
     }
   if (type->num_fields () > i
       && strcmp (TYPE_FIELD_NAME (type, i), "end") == 0)
     {
-      *kind = (*kind == BOTH_BOUND_DEFAULT
-	       ? LOW_BOUND_DEFAULT : NONE_BOUND_DEFAULT);
+      *kind = (*kind == (RANGE_LOW_BOUND_DEFAULT | RANGE_HIGH_BOUND_DEFAULT)
+	       ? RANGE_LOW_BOUND_DEFAULT : RANGE_STANDARD);
       *high = value_as_long (value_field (range, i));
 
       if (rust_inclusive_range_type_p (type))
@@ -1206,7 +1204,7 @@ rust_subscript (struct expression *exp, int *pos, enum noside noside,
   struct type *rhstype;
   LONGEST low, high_bound;
   /* Initialized to appease the compiler.  */
-  enum range_type kind = BOTH_BOUND_DEFAULT;
+  range_types kind = RANGE_LOW_BOUND_DEFAULT | RANGE_HIGH_BOUND_DEFAULT;
   LONGEST high = 0;
   int want_slice = 0;
 
@@ -1303,8 +1301,7 @@ rust_subscript (struct expression *exp, int *pos, enum noside noside,
       else
 	error (_("Cannot subscript non-array type"));
 
-      if (want_slice
-	  && (kind == BOTH_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT))
+      if (want_slice && (kind & RANGE_LOW_BOUND_DEFAULT))
 	low = low_bound;
       if (low < 0)
 	error (_("Index less than zero"));
@@ -1322,7 +1319,7 @@ rust_subscript (struct expression *exp, int *pos, enum noside noside,
 	  CORE_ADDR addr;
 	  struct value *addrval, *tem;
 
-	  if (kind == BOTH_BOUND_DEFAULT || kind == HIGH_BOUND_DEFAULT)
+	  if (kind & RANGE_HIGH_BOUND_DEFAULT)
 	    high = high_bound;
 	  if (high < 0)
 	    error (_("High index less than zero"));