fortran: change subrange enum to bit field

Change Fortran subrange enum for subrange expressions to
represent a bitfield for easier manipulation.  Consequently
also change occurences and evaluation of said enum.  The
behaviour of GDB is unchanged.

2013-11-27  Christoph Weinmann  <christoph.t.weinmann@intel.com>

	* eval.c (value_f90_subarray): Change evaluation of the
	subarray boundaries.  Set boundaries to be either user
	provided (bit in range_type was set), or take the default
	value if the boundary was not provided by the user.
	* expprint.c (print_subexp_standard): Alter boundary com-
	putations to use updated range_type enum.
	* expprint.h (dump_subexp_body_standard): Dito.
	* expression.h (range_type): Change the enum to use bit
	values for each boundary, if set by the user.
	* f-exp.y (subrange): Change rules for subrange expressions
	to write the relevant bit sequence onto the elt stack.
	* parse.c (operator_length_standard): In case of OP_RANGE
	change the calculation of the number of	arguments on the
	elt stack, depending on the number of boundaries provided
	by the user.
	* rust-exp.y (convert_ast_to_expression): Modify calcula-
	tion of subscript elements to use altered range_type.
	* rust-lang.c (rust_range): Dito.
	* rust-lang.c (rust_subscript): Dito.

Signed-off-by: Christoph Weinmann <christoph.t.weinmann@intel.com>

7 files changed, 45 insertions, 65 deletions

diff --git a/gdb/eval.c b/gdb/eval.c
index a6b729d..2d9eb31 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -482,12 +482,12 @@ value_f90_subarray (struct value *array, struct expression *exp,
 	  /* If a lower bound was provided by the user, the bit has been
 	     set and we can assign the value from the elt stack.  Same for
 	     upper bound.  */
-	  if ((range->f90_range_type == HIGH_BOUND_DEFAULT)
-	      || range->f90_range_type == NONE_BOUND_DEFAULT)
+	  if ((range->f90_range_type & SUBARRAY_LOW_BOUND)
+	      == SUBARRAY_LOW_BOUND)
 	    range->low = value_as_long (evaluate_subexp (NULL_TYPE, exp,
 							 pos, noside));
-	  if ((range->f90_range_type == LOW_BOUND_DEFAULT)
-	      || range->f90_range_type == NONE_BOUND_DEFAULT)
+	  if ((range->f90_range_type & SUBARRAY_HIGH_BOUND)
+	      == SUBARRAY_HIGH_BOUND)
 	    range->high = value_as_long (evaluate_subexp (NULL_TYPE, exp,
 							  pos, noside));
 	}
@@ -528,12 +528,10 @@ value_f90_subarray (struct value *array, struct expression *exp,
 
 	    /* If no lower bound was provided by the user, we take the
 	       default boundary.  Same for the high bound.  */
-	    if ((range->f90_range_type == LOW_BOUND_DEFAULT)
-		|| (range->f90_range_type == BOTH_BOUND_DEFAULT))
+	    if ((range->f90_range_type & SUBARRAY_LOW_BOUND) == 0)
 	      range->low = TYPE_LOW_BOUND (index_type);
 
-	    if ((range->f90_range_type == HIGH_BOUND_DEFAULT)
-		|| (range->f90_range_type == BOTH_BOUND_DEFAULT))
+	    if ((range->f90_range_type & SUBARRAY_HIGH_BOUND) == 0)
 	      range->high = TYPE_HIGH_BOUND (index_type);
 
 	    /* Both user provided low and high bound have to be inside the
diff --git a/gdb/expprint.c b/gdb/expprint.c
index c37ecb0..214d58e 100644
--- a/gdb/expprint.c
+++ b/gdb/expprint.c
@@ -568,12 +568,10 @@ print_subexp_standard (struct expression *exp, int *pos,
 	*pos += 2;
 
 	fputs_filtered ("RANGE(", stream);
-	if (range_type == HIGH_BOUND_DEFAULT
-	    || range_type == NONE_BOUND_DEFAULT)
+	if ((range_type & SUBARRAY_LOW_BOUND) == SUBARRAY_LOW_BOUND)
 	  print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
 	fputs_filtered ("..", stream);
-	if (range_type == LOW_BOUND_DEFAULT
-	    || range_type == NONE_BOUND_DEFAULT)
+	if ((range_type & SUBARRAY_HIGH_BOUND) == SUBARRAY_HIGH_BOUND)
 	  print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
 	fputs_filtered (")", stream);
 	return;
@@ -1055,16 +1053,16 @@ dump_subexp_body_standard (struct expression *exp,
 
 	switch (range_type)
 	  {
-	  case BOTH_BOUND_DEFAULT:
+	  case SUBARRAY_NONE_BOUND:
 	    fputs_filtered ("Range '..'", stream);
 	    break;
-	  case LOW_BOUND_DEFAULT:
+	  case SUBARRAY_HIGH_BOUND:
 	    fputs_filtered ("Range '..EXP'", stream);
 	    break;
-	  case HIGH_BOUND_DEFAULT:
+	  case SUBARRAY_LOW_BOUND:
 	    fputs_filtered ("Range 'EXP..'", stream);
 	    break;
-	  case NONE_BOUND_DEFAULT:
+	  case (SUBARRAY_LOW_BOUND | SUBARRAY_HIGH_BOUND):
 	    fputs_filtered ("Range 'EXP..EXP'", stream);
 	    break;
 	  default:
@@ -1072,11 +1070,9 @@ dump_subexp_body_standard (struct expression *exp,
 	    break;
 	  }
 
-	if (range_type == HIGH_BOUND_DEFAULT
-	    || range_type == NONE_BOUND_DEFAULT)
+	if ((range_type & SUBARRAY_LOW_BOUND) == SUBARRAY_LOW_BOUND)
 	  elt = dump_subexp (exp, stream, elt);
-	if (range_type == LOW_BOUND_DEFAULT
-	    || range_type == NONE_BOUND_DEFAULT)
+	if ((range_type & SUBARRAY_HIGH_BOUND) == SUBARRAY_HIGH_BOUND)
 	  elt = dump_subexp (exp, stream, elt);
       }
       break;
diff --git a/gdb/expression.h b/gdb/expression.h
index 4952d84..5a6b720 100644
--- a/gdb/expression.h
+++ b/gdb/expression.h
@@ -152,17 +152,14 @@ extern void dump_raw_expression (struct expression *,
 				 struct ui_file *, char *);
 extern void dump_prefix_expression (struct expression *, struct ui_file *);
 
-/* In an OP_RANGE expression, either bound could be empty, indicating
-   that its value is by default that of the corresponding bound of the
-   array or string.  So we have four sorts of subrange.  This
-   enumeration type is to identify this.  */
-   
+/* In an OP_RANGE expression, either bound can be provided by the user, or not.
+   This enumeration type is to identify this.  */
+
 enum range_type
   {
-    BOTH_BOUND_DEFAULT,		/* "(:)"  */
-    LOW_BOUND_DEFAULT,		/* "(:high)"  */
-    HIGH_BOUND_DEFAULT,		/* "(low:)"  */
-    NONE_BOUND_DEFAULT		/* "(low:high)"  */
+    SUBARRAY_NONE_BOUND = 0x0,		/* "( : )"  */
+    SUBARRAY_LOW_BOUND = 0x1,		/* "(low:)"  */
+    SUBARRAY_HIGH_BOUND = 0x2		/* "(:high)"  */
   };
 
 #endif /* !defined (EXPRESSION_H) */
diff --git a/gdb/f-exp.y b/gdb/f-exp.y
index dc131c1..e2c54b6 100644
--- a/gdb/f-exp.y
+++ b/gdb/f-exp.y
@@ -260,26 +260,27 @@ arglist	:	arglist ',' exp   %prec ABOVE_COMMA
 /* There are four sorts of subrange types in F90.  */
 
 subrange:	exp ':' exp	%prec ABOVE_COMMA
-			{ write_exp_elt_opcode (pstate, OP_RANGE); 
-			  write_exp_elt_longcst (pstate, NONE_BOUND_DEFAULT);
+			{ write_exp_elt_opcode (pstate, OP_RANGE);
+			  write_exp_elt_longcst (pstate,
+						 SUBARRAY_LOW_BOUND | SUBARRAY_HIGH_BOUND);
 			  write_exp_elt_opcode (pstate, OP_RANGE); }
 	;
 
 subrange:	exp ':'	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_RANGE);
-			  write_exp_elt_longcst (pstate, HIGH_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, SUBARRAY_LOW_BOUND);
 			  write_exp_elt_opcode (pstate, OP_RANGE); }
 	;
 
 subrange:	':' exp	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_RANGE);
-			  write_exp_elt_longcst (pstate, LOW_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, SUBARRAY_HIGH_BOUND);
 			  write_exp_elt_opcode (pstate, OP_RANGE); }
 	;
 
 subrange:	':'	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_RANGE);
-			  write_exp_elt_longcst (pstate, BOTH_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, 0);
 			  write_exp_elt_opcode (pstate, OP_RANGE); }
 	;
 
diff --git a/gdb/parse.c b/gdb/parse.c
index 2b00708..6d54a77 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -1006,22 +1006,17 @@ operator_length_standard (const struct expression *expr, int endpos,
 
     case OP_RANGE:
       oplen = 3;
+      args = 0;
       range_type = (enum range_type)
 	longest_to_int (expr->elts[endpos - 2].longconst);
 
-      switch (range_type)
-	{
-	case LOW_BOUND_DEFAULT:
-	case HIGH_BOUND_DEFAULT:
-	  args = 1;
-	  break;
-	case BOTH_BOUND_DEFAULT:
-	  args = 0;
-	  break;
-	case NONE_BOUND_DEFAULT:
-	  args = 2;
-	  break;
-	}
+      /* Increment the argument counter for each argument
+	 provided by the user.  */
+      if ((range_type & SUBARRAY_LOW_BOUND) == SUBARRAY_LOW_BOUND)
+	args++;
+
+      if ((range_type & SUBARRAY_HIGH_BOUND) == SUBARRAY_HIGH_BOUND)
+	args++;
 
       break;
 
diff --git a/gdb/rust-exp.y b/gdb/rust-exp.y
index aeb6058..b1b9633 100644
--- a/gdb/rust-exp.y
+++ b/gdb/rust-exp.y
@@ -2429,23 +2429,17 @@ convert_ast_to_expression (struct parser_state *state,
 
     case OP_RANGE:
       {
-	enum range_type kind = BOTH_BOUND_DEFAULT;
+	enum range_type kind = SUBARRAY_NONE_BOUND;
 
 	if (operation->left.op != NULL)
 	  {
 	    convert_ast_to_expression (state, operation->left.op, top);
-	    kind = HIGH_BOUND_DEFAULT;
+	    kind = SUBARRAY_LOW_BOUND;
 	  }
 	if (operation->right.op != NULL)
 	  {
 	    convert_ast_to_expression (state, operation->right.op, top);
-	    if (kind == BOTH_BOUND_DEFAULT)
-	      kind = LOW_BOUND_DEFAULT;
-	    else
-	      {
-		gdb_assert (kind == HIGH_BOUND_DEFAULT);
-		kind = NONE_BOUND_DEFAULT;
-	      }
+	    kind = (range_type) (kind | SUBARRAY_HIGH_BOUND);
 	  }
 	write_exp_elt_opcode (state, OP_RANGE);
 	write_exp_elt_longcst (state, kind);
diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index 17b20c6..295002f 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -1241,9 +1241,9 @@ 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)
+  if ((kind & SUBARRAY_LOW_BOUND) == SUBARRAY_LOW_BOUND)
     low = evaluate_subexp (NULL_TYPE, exp, pos, noside);
-  if (kind == LOW_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT)
+  if ((kind & SUBARRAY_HIGH_BOUND) == SUBARRAY_HIGH_BOUND)
     high = evaluate_subexp (NULL_TYPE, exp, pos, noside);
 
   if (noside == EVAL_SKIP)
@@ -1332,7 +1332,7 @@ rust_compute_range (struct type *type, struct value *range,
 
   *low = 0;
   *high = 0;
-  *kind = BOTH_BOUND_DEFAULT;
+  *kind = SUBARRAY_NONE_BOUND;
 
   if (TYPE_NFIELDS (type) == 0)
     return;
@@ -1340,15 +1340,14 @@ 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 = SUBARRAY_LOW_BOUND;
       *low = value_as_long (value_field (range, 0));
       ++i;
     }
   if (TYPE_NFIELDS (type) > i
       && strcmp (TYPE_FIELD_NAME (type, i), "end") == 0)
     {
-      *kind = (*kind == BOTH_BOUND_DEFAULT
-	       ? LOW_BOUND_DEFAULT : NONE_BOUND_DEFAULT);
+      *kind = (range_type) (*kind | SUBARRAY_HIGH_BOUND);
       *high = value_as_long (value_field (range, i));
     }
 }
@@ -1363,7 +1362,7 @@ 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;
+  enum range_type kind = SUBARRAY_NONE_BOUND;
   LONGEST high = 0;
   int want_slice = 0;
 
@@ -1425,7 +1424,7 @@ rust_subscript (struct expression *exp, int *pos, enum noside noside,
 	error (_("Cannot subscript non-array type"));
 
       if (want_slice
-	  && (kind == BOTH_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT))
+	  && ((kind & SUBARRAY_LOW_BOUND) != SUBARRAY_LOW_BOUND))
 	low = low_bound;
       if (low < 0)
 	error (_("Index less than zero"));
@@ -1443,7 +1442,7 @@ 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 & SUBARRAY_HIGH_BOUND) != SUBARRAY_HIGH_BOUND)
 	    high = high_bound;
 	  if (high < 0)
 	    error (_("High index less than zero"));