http://sourceware.org/ml/gdb-patches/2016-02/msg00845.html

Subject: [PATCH v2 3/6] fortran: change subrange enum to bit field

From: Christoph Weinmann <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 164d7ab..9b8b051 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 9343abb..b1206de 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 eeca107..4d56bf7 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 4191fc6..d500279 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;

-- 

2.5.0