http://sourceware.org/ml/gdb-patches/2016-02/msg00842.html

Subject: [PATCH v2 4/6] fortran: enable parsing of stride parameter for subranges

From: Christoph Weinmann <christoph.t.weinmann@intel.com>

Allow the user to provide a stride parameter for Fortran

subarrays.  The stride parameter can be any integer except

'0'.  The default stride value is '1'.

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

	* eval.c (value_f90_subarray): Add expression evaluation

	for a stride parameter in a Fortran range expression.

	* f-exp.y: Add yacc rules for writing info on the elt stack

	when the user provided a stride argument.

	* f-lang.h (F90_RANGE): Add field to enum to show when a

	stride was provided by the user.

	* parse.c (operator_length_standard): Check if a stride

	value was provided, and increment argument counter

	accordingly.

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

---

 gdb/eval.c   | 10 +++++++++-

 gdb/f-exp.y  | 33 +++++++++++++++++++++++++++++++--

 gdb/f-lang.h |  5 +++--

 gdb/parse.c  |  3 +++

 4 files changed, 46 insertions(+), 5 deletions(-)

diff --git a/gdb/eval.c b/gdb/eval.c

index 9b8b051..308ada3 100644

--- a/gdb/eval.c

+++ b/gdb/eval.c

@@ -438,7 +438,7 @@ value_f90_subarray (struct value *array, struct expression *exp,

       struct subscript_range

       {

         enum f90_range_type f90_range_type;

-        LONGEST low, high;

+        LONGEST low, high, stride;

       }

       range;

       LONGEST number;

@@ -488,6 +488,14 @@ value_f90_subarray (struct value *array, struct expression *exp,

 	      == SUBARRAY_HIGH_BOUND)

 	    range->high = value_as_long (evaluate_subexp (NULL_TYPE, exp,

 							  pos, noside));

+

+	  /* Assign the user's stride value if provided.  */

+	  if ((range->f90_range_type & SUBARRAY_STRIDE) == SUBARRAY_STRIDE)

+	    range->stride = value_as_long (evaluate_subexp (NULL_TYPE, exp,

+							    pos, noside));

+	  /* Assign the default stride value '1'.  */

+	  else

+	    range->stride = 1;

 	}

       /* User input is an index.  E.g.: "p arry(5)".  */

       else

diff --git a/gdb/f-exp.y b/gdb/f-exp.y

index b1206de..5151fee 100644

--- a/gdb/f-exp.y

+++ b/gdb/f-exp.y

@@ -316,8 +316,8 @@ arglist	:	arglist ',' exp   %prec ABOVE_COMMA

 subrange:	exp ':' exp	%prec ABOVE_COMMA

 			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);

-			  write_exp_elt_longcst (pstate,

-						 SUBARRAY_LOW_BOUND | SUBARRAY_HIGH_BOUND);

+			  write_exp_elt_longcst (pstate, SUBARRAY_LOW_BOUND

+						 | SUBARRAY_HIGH_BOUND);

 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }

 	;

@@ -339,6 +339,35 @@ subrange:	':'	%prec ABOVE_COMMA

 			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }

 	;

+/* Each subrange type can have a stride argument.  */

+subrange:	exp ':' exp ':' exp %prec ABOVE_COMMA

+			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);

+			  write_exp_elt_longcst (pstate, SUBARRAY_LOW_BOUND

+						 | SUBARRAY_HIGH_BOUND

+						 | SUBARRAY_STRIDE);

+			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }

+	;

+

+subrange:	exp ':' ':' exp %prec ABOVE_COMMA

+			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);

+			  write_exp_elt_longcst (pstate, SUBARRAY_LOW_BOUND

+						 | SUBARRAY_STRIDE);

+			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }

+	;

+

+subrange:	':' exp ':' exp %prec ABOVE_COMMA

+			{ write_exp_elt_opcode (pstate, OP_F90_RANGE);

+			  write_exp_elt_longcst (pstate, SUBARRAY_HIGH_BOUND

+						 | SUBARRAY_STRIDE);

+			  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, SUBARRAY_STRIDE);

+			  write_exp_elt_opcode (pstate, OP_F90_RANGE); }

+	;

+

 complexnum:     exp ',' exp 

                 	{ }                          

         ;

diff --git a/gdb/f-lang.h b/gdb/f-lang.h

index 4d56bf7..0ad57af 100644

--- a/gdb/f-lang.h

+++ b/gdb/f-lang.h

@@ -44,8 +44,9 @@ extern void f_val_print (struct type *, const gdb_byte *, int, CORE_ADDR,

 enum f90_range_type

   {

-    SUBARRAY_LOW_BOUND = 0x1,		/* "(low:)"  */

-    SUBARRAY_HIGH_BOUND = 0x2		/* "(:high)"  */

+    SUBARRAY_LOW_BOUND = 0x1,		/* "(low:)" or "(low::)" */

+    SUBARRAY_HIGH_BOUND = 0x2,		/* "(:high)" or "(:high:)"  */

+    SUBARRAY_STRIDE = 0x4		/* "(::stride)"  */

   };

 /* A common block.  */

diff --git a/gdb/parse.c b/gdb/parse.c

index d500279..07248c3 100644

--- a/gdb/parse.c

+++ b/gdb/parse.c

@@ -1018,6 +1018,9 @@ operator_length_standard (const struct expression *expr, int endpos,

       if ((range_type & SUBARRAY_HIGH_BOUND) == SUBARRAY_HIGH_BOUND)

 	args++;

+      if ((range_type & SUBARRAY_STRIDE) == SUBARRAY_STRIDE)

+	args++;

+

       break;

     default:

-- 

2.5.0