From: Christoph Weinmann <christoph.t.weinmann@intel.com>
[PATCH 3/6] fortran: change subrange enum to bit field
https://sourceware.org/ml/gdb-patches/2015-12/msg00006.html
Message-Id: <1448976075-11456-4-git-send-email-christoph.t.weinmann@intel.com>

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 f90_range_type was set) or take the
	default value if the boundary was not provided by the user.
	* f-exp.y (subrange): Change rules for subrange expressions
	to write the relevant bit sequence onto the elt stack.
	* f-lang.h (f90_range_type): Change the enum to use bit
	values for each boundary, if set by the user.
	* parse.c (operator_length_standard): In case of
	OP_F90_RANGE change the calculation of the number of
	arguments on the elt stack, depending on the number of
	boundaries provided by the user.



Signed-off-by: Christoph Weinmann <christoph.t.weinmann@intel.com>
---
 gdb/eval.c   |   14 ++++++--------
 gdb/f-exp.y  |   11 ++++++-----
 gdb/f-lang.h |    6 ++----
 gdb/parse.c  |   21 ++++++++-------------
 4 files changed, 22 insertions(+), 30 deletions(-)

diff --git a/gdb/eval.c b/gdb/eval.c
index 0c1b607..47ba602 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -480,12 +480,12 @@ 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));
 	}
@@ -526,12 +526,10 @@ 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/f-exp.y b/gdb/f-exp.y
index ab23df0..1ff768c 100644
--- a/gdb/f-exp.y
+++ b/gdb/f-exp.y
@@ -315,26 +315,27 @@ 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_F90_RANGE); 
-			  write_exp_elt_longcst (pstate, NONE_BOUND_DEFAULT);
+			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);
+			  write_exp_elt_longcst (pstate,
+						 SUBARRAY_LOW_BOUND | SUBARRAY_HIGH_BOUND);
 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }
 	;
 
 subrange:	exp ':'	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);
-			  write_exp_elt_longcst (pstate, HIGH_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, SUBARRAY_LOW_BOUND);
 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }
 	;
 
 subrange:	':' exp	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);
-			  write_exp_elt_longcst (pstate, LOW_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, SUBARRAY_HIGH_BOUND);
 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }
 	;
 
 subrange:	':'	%prec ABOVE_COMMA
 			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);
-			  write_exp_elt_longcst (pstate, BOTH_BOUND_DEFAULT);
+			  write_exp_elt_longcst (pstate, 0);
 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }
 	;
 
diff --git a/gdb/f-lang.h b/gdb/f-lang.h
index f7a14d7..20cf5bd 100644
--- a/gdb/f-lang.h
+++ b/gdb/f-lang.h
@@ -44,10 +44,8 @@ extern void f_val_print (struct type *, const gdb_byte *, int, CORE_ADDR,
    
 enum f90_range_type
   {
-    BOTH_BOUND_DEFAULT,		/* "(:)"  */
-    LOW_BOUND_DEFAULT,		/* "(:high)"  */
-    HIGH_BOUND_DEFAULT,		/* "(low:)"  */
-    NONE_BOUND_DEFAULT		/* "(low:high)"  */
+    SUBARRAY_LOW_BOUND = 0x1,		/* "(low:)"  */
+    SUBARRAY_HIGH_BOUND = 0x2		/* "(:high)"  */
   };
 
 /* A common block.  */
diff --git a/gdb/parse.c b/gdb/parse.c
index a24c52a..7e45c05 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -1006,22 +1006,17 @@ operator_length_standard (const struct expression *expr, int endpos,
 
     case OP_F90_RANGE:
       oplen = 3;
+      args = 0;
       range_type = (enum f90_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;
 
-- 
1.7.0.7