fortran: allow multi-dimensional subarrays

Add an argument count for subrange expressions in Fortran.
Based on the counted value calculate a new array with the
elements specified by the user.  First parse the user input,
secondly copy the desired array values into the return
array, thirdly re-create the necessary ranges and bounds.

1|  program prog
2|    integer :: ary(10,5) = (/ (i,i=1,10) (j, j=1,5) /)
3|  end program prog

(gdb) print ary(2:4,1:3)
old> Syntax error in expression near ':3'
new> $3 = ( ( 21, 31, 41) ( 22, 32, 42) ( 23, 33, 43) )

2013-11-25  Christoph Weinmann  <christoph.t.weinmann@intel.com>

	* eval.c (multi_f77_subscript): Remove function.
	* eval.c (evaluate_subrange_expr): When evaluating
	an array or string expression, call
	value_f90_subarray.
	* eval.c (value_f90_subarray): Add argument parsing
	and compute result array based on user input.
	* f-exp.y: Increment argument counter for every subrange
	expression entered by the user.
	* valops.c (value_slice): Call value_slice_1 with
	additional default argument.
	* valops.c (value_slice_1): Add functionality to
	copy and return result values based on input.
	* value.h: Add function definition.

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

4 files changed, 379 insertions, 97 deletions

diff --git a/gdb/eval.c b/gdb/eval.c
index 00a107c..40ce446 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -399,29 +399,254 @@ init_array_element (struct value *array, struct value *element,
   return index;
 }
 
+/* Evaluates any operation on Fortran arrays or strings with at least
+   one user provided parameter.  Expects the input ARRAY to be either
+   an array, or a string.  Evaluates EXP by incrementing POS, and
+   writes the content from the elt stack into a local struct.  NARGS
+   specifies number of literal or range arguments the user provided.
+   NARGS must be the same number as ARRAY has dimensions.  */
+
 static struct value *
-value_f90_subarray (struct value *array,
-		    struct expression *exp, int *pos, enum noside noside)
+value_f90_subarray (struct value *array, struct expression *exp,
+		    int *pos, int nargs, enum noside noside)
 {
-  int pc = (*pos) + 1;
+  int i, dim_count = 0;
   LONGEST low_bound, high_bound;
-  struct type *range = check_typedef (TYPE_INDEX_TYPE (value_type (array)));
-  enum range_type range_type
-    = (enum range_type) longest_to_int (exp->elts[pc].longconst);
- 
-  *pos += 3;
-
-  if (range_type == LOW_BOUND_DEFAULT || range_type == BOTH_BOUND_DEFAULT)
-    low_bound = TYPE_LOW_BOUND (range);
-  else
-    low_bound = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
+  struct value *new_array = array;
+  struct type *array_type = check_typedef (value_type (new_array));
+  struct type *elt_type;
+
+  typedef struct subscript_range
+  {
+    enum range_type f90_range_type;
+    LONGEST low, high;
+  } subscript_range;
+
+  typedef enum subscript_kind
+  {
+    SUBSCRIPT_RANGE,    /* e.g. "(lowbound:highbound)"  */
+    SUBSCRIPT_INDEX    /* e.g. "(literal)"  */
+  } kind;
+
+  /* Local struct to hold user data for Fortran subarray dimensions.  */
+  struct subscript_store
+  {
+    /* For every dimension, we are either working on a range or an index
+       expression, so we store this info separately for later.  */
+    enum subscript_kind kind;
+
+    /* We also store either the lower and upper bound info, or the index
+       number.  Before evaluation of the input values, we do not know if we are
+       actually working on a range of ranges, or an index in a range.  So as a
+       first step we store all input in a union.  The array calculation itself
+       deals with this later on.  */
+    union element_range
+    {
+      subscript_range range;
+      LONGEST number;
+    } U;
+  } *subscript_array;
+
+  /* Check if the number of arguments provided by the user matches
+     the number of dimension of the array.  A string has only one
+     dimension.  */
+  if (nargs != calc_f77_array_dims (value_type (new_array)))
+    error (_("Wrong number of subscripts"));
+
+  subscript_array = (struct subscript_store*) alloca (sizeof (*subscript_array) * nargs);
+
+  /* Parse the user input into the SUBSCRIPT_ARRAY to store it.  We need
+     to evaluate it first, as the input is from left-to-right.  The
+     array is stored from right-to-left.  So we have to use the user
+     input in reverse order.  Later on, we need the input information to
+     re-calculate the output array.  For multi-dimensional arrays, we
+     can be dealing with any possible combination of ranges and indices
+     for every dimension.  */
+  for (i = 0; i < nargs; i++)
+    {
+      struct subscript_store *index = &subscript_array[i];
 
-  if (range_type == HIGH_BOUND_DEFAULT || range_type == BOTH_BOUND_DEFAULT)
-    high_bound = TYPE_HIGH_BOUND (range);
-  else
-    high_bound = value_as_long (evaluate_subexp (NULL_TYPE, exp, pos, noside));
+      /* The user input is a range, with or without lower and upper bound.
+	 E.g.: "p arry(2:5)", "p arry( :5)", "p arry( : )", etc.  */
+      if (exp->elts[*pos].opcode == OP_RANGE)
+	{
+	  int pc = (*pos) + 1;
+	  subscript_range *range;
+
+	  index->kind = SUBSCRIPT_RANGE;
+	  range = &index->U.range;
+
+	  *pos += 3;
+	  range->f90_range_type = (enum range_type) longest_to_int (exp->elts[pc].longconst);
+
+	  /* 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)
+	    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)
+	    range->high = value_as_long (evaluate_subexp (NULL_TYPE, exp,
+							  pos, noside));
+	}
+      /* User input is an index.  E.g.: "p arry(5)".  */
+      else
+	{
+	  struct value *val;
+
+	  index->kind = SUBSCRIPT_INDEX;
+
+	  /* Evaluate each subscript; it must be a legal integer in F77.  This
+	     ensures the validity of the provided index.  */
+	  val = evaluate_subexp_with_coercion (exp, pos, noside);
+	  index->U.number = value_as_long (val);
+	}
+
+    }
+
+  /* Traverse the array from right to left and evaluate each corresponding
+     user input.  VALUE_SUBSCRIPT is called for every index, until a range
+     expression is evaluated.  After a range expression has been evaluated,
+     every subsequent expression is also treated as a range.  */
+  for (i = nargs - 1; i >= 0; i--)
+    {
+      struct subscript_store *index = &subscript_array[i];
+      struct type *index_type = TYPE_INDEX_TYPE (array_type);
+
+      switch (index->kind)
+	{
+	case SUBSCRIPT_RANGE:
+	  {
+
+	    /* When we hit the first range specified by the user, we must
+	       treat any subsequent user entry as a range.  We simply
+	       increment DIM_COUNT which tells us how many times we are
+	       calling VALUE_SLICE_1.  */
+	    subscript_range *range = &index->U.range;
+
+	    /* 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))
+	      range->low = TYPE_LOW_BOUND (index_type);
+
+	    if ((range->f90_range_type == HIGH_BOUND_DEFAULT)
+		|| (range->f90_range_type == BOTH_BOUND_DEFAULT))
+	      range->high = TYPE_HIGH_BOUND (index_type);
+
+	    /* Both user provided low and high bound have to be inside the
+	       array bounds.  Throw an error if not.  */
+	    if (range->low < TYPE_LOW_BOUND (index_type)
+		|| range->low > TYPE_HIGH_BOUND (index_type)
+		|| range->high < TYPE_LOW_BOUND (index_type)
+		|| range->high > TYPE_HIGH_BOUND (index_type))
+	      error (_("provided bound(s) outside array bound(s)"));
+
+	    /* DIM_COUNT counts every user argument that is treated as a range.
+	       This is necessary for expressions like 'print array(7, 8:9).
+	       Here the first argument is a literal, but must be treated as a
+	       range argument to allow the correct output representation.  */
+	    dim_count++;
+
+	    new_array
+	      = value_slice_1 (new_array,
+			       longest_to_int (range->low),
+			       longest_to_int (range->high - range->low + 1),
+			       dim_count);
+	  }
+	  break;
+
+	case SUBSCRIPT_INDEX:
+	  {
+	    /* DIM_COUNT only stays '0' when no range argument was processed
+	       before, starting from the last dimension.  This way we can
+	       reduce the number of dimensions from the result array.
+	       However, if a range has been processed before an index, we
+	       treat the index like a range with equal low- and high bounds
+	       to get the value offset right.  */
+	    if (dim_count == 0)
+	      new_array
+	        = value_subscripted_rvalue (new_array, index->U.number,
+					    f77_get_lowerbound (value_type
+								  (new_array)));
+	    else
+	      {
+		/* Check for valid index input.  */
+		if (index->U.number < TYPE_LOW_BOUND (index_type)
+		    || index->U.number > TYPE_HIGH_BOUND (index_type))
+		  error (_("error no such vector element"));
+
+		dim_count++;
+		new_array = value_slice_1 (new_array,
+					   longest_to_int (index->U.number),
+					   1, /* length is '1' element  */
+					   dim_count);
+	      }
+
+	  }
+	  break;
+	}
+    }
+
+  /* With DIM_COUNT > 1 we currently have a one dimensional array, but expect
+     an array of arrays, depending on how many ranges have been provided by
+     the user.  So we need to rebuild the array dimensions for printing it
+     correctly.
+     Starting from right to left in the user input, after we hit the first
+     range argument every subsequent argument is also treated as a range.
+     E.g.:
+     "p ary(3, 7, 2:15)" in Fortran has only 1 dimension, but we calculated 3
+     ranges.
+     "p ary(3, 7:12, 4)" in Fortran has only 1 dimension, but we calculated 2
+     ranges.
+     "p ary(2:4, 5, 7)" in Fortran has only 1 dimension, and we calculated 1
+     range.  */
+  if (dim_count > 1)
+    {
+      struct value *v = NULL;
+
+      elt_type = TYPE_TARGET_TYPE (value_type (new_array));
 
-  return value_slice (array, low_bound, high_bound - low_bound + 1);
+      /* Every SUBSCRIPT_RANGE in the user input signifies an actual range in
+	 the output array.  So we traverse the SUBSCRIPT_ARRAY again, looking
+	 for a range entry.  When we find one, we use the range info to create
+	 an additional range_type to set the correct bounds and dimensions for
+	 the output array.  */
+      for (i = 0; i < nargs; i++)
+	{
+	  struct subscript_store *index = &subscript_array[i];
+
+	  if (index->kind == SUBSCRIPT_RANGE)
+	    {
+	      struct type *range_type, *interim_array_type;
+
+	      range_type
+		= create_static_range_type (NULL,
+					    elt_type,
+					    1,
+					    index->U.range.high
+					      - index->U.range.low + 1);
+
+	      interim_array_type = create_array_type (NULL,
+						      elt_type,
+						      range_type);
+
+	      TYPE_CODE (interim_array_type)
+		= TYPE_CODE (value_type (new_array));
+
+	      v = allocate_value (interim_array_type);
+
+	      elt_type = value_type (v);
+	    }
+
+	}
+      value_contents_copy (v, 0, new_array, 0, TYPE_LENGTH (elt_type));
+      return v;
+    }
+
+  return new_array;
 }
 
 
@@ -1810,14 +2035,11 @@ evaluate_subexp_standard (struct type *expect_type,
       switch (code)
 	{
 	case TYPE_CODE_ARRAY:
-	  if (exp->elts[*pos].opcode == OP_RANGE)
-	    return value_f90_subarray (arg1, exp, pos, noside);
-	  else
-	    goto multi_f77_subscript;
+	  return value_f90_subarray (arg1, exp, pos, nargs, noside);
 
 	case TYPE_CODE_STRING:
 	  if (exp->elts[*pos].opcode == OP_RANGE)
-	    return value_f90_subarray (arg1, exp, pos, noside);
+	    return value_f90_subarray (arg1, exp, pos, 1, noside);
 	  else
 	    {
 	      arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
@@ -2223,49 +2445,6 @@ evaluate_subexp_standard (struct type *expect_type,
 	}
       return (arg1);
 
-    multi_f77_subscript:
-      {
-	LONGEST subscript_array[MAX_FORTRAN_DIMS];
-	int ndimensions = 1, i;
-	struct value *array = arg1;
-
-	if (nargs > MAX_FORTRAN_DIMS)
-	  error (_("Too many subscripts for F77 (%d Max)"), MAX_FORTRAN_DIMS);
-
-	ndimensions = calc_f77_array_dims (type);
-
-	if (nargs != ndimensions)
-	  error (_("Wrong number of subscripts"));
-
-	gdb_assert (nargs > 0);
-
-	/* Now that we know we have a legal array subscript expression 
-	   let us actually find out where this element exists in the array.  */
-
-	/* Take array indices left to right.  */
-	for (i = 0; i < nargs; i++)
-	  {
-	    /* Evaluate each subscript; it must be a legal integer in F77.  */
-	    arg2 = evaluate_subexp_with_coercion (exp, pos, noside);
-
-	    /* Fill in the subscript array.  */
-
-	    subscript_array[i] = value_as_long (arg2);
-	  }
-
-	/* Internal type of array is arranged right to left.  */
-	for (i = nargs; i > 0; i--)
-	  {
-	    struct type *array_type = check_typedef (value_type (array));
-	    LONGEST index = subscript_array[i - 1];
-
-	    array = value_subscripted_rvalue (array, index,
-					      f77_get_lowerbound (array_type));
-	  }
-
-	return array;
-      }
-
     case BINOP_LOGICAL_AND:
       arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
       if (noside == EVAL_SKIP)
@@ -3123,6 +3302,9 @@ calc_f77_array_dims (struct type *array_type)
   int ndimen = 1;
   struct type *tmp_type;
 
+  if (TYPE_CODE (array_type) == TYPE_CODE_STRING)
+    return 1;
+
   if ((TYPE_CODE (array_type) != TYPE_CODE_ARRAY))
     error (_("Can't get dimensions for a non-array type"));
 
diff --git a/gdb/f-exp.y b/gdb/f-exp.y
index e3148a3..dc131c1 100644
--- a/gdb/f-exp.y
+++ b/gdb/f-exp.y
@@ -253,6 +253,8 @@ arglist :	subrange
    
 arglist	:	arglist ',' exp   %prec ABOVE_COMMA
 			{ arglist_len++; }
+	|	arglist ',' subrange	%prec ABOVE_COMMA
+			{ arglist_len++; }
 	;
 
 /* There are four sorts of subrange types in F90.  */
diff --git a/gdb/valops.c b/gdb/valops.c
index 40392e8..877280f 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -3775,56 +3775,152 @@ value_of_this_silent (const struct language_defn *lang)
 struct value *
 value_slice (struct value *array, int lowbound, int length)
 {
+  /* Pass unaltered arguments to VALUE_SLICE_1, plus a CALL_COUNT of '1' as we
+     are only considering the highest dimension, or we are working on a one
+     dimensional array.  So we call VALUE_SLICE_1 exactly once.  */
+  return value_slice_1 (array, lowbound, length, 1);
+}
+
+/* VALUE_SLICE_1 is called for each array dimension to calculate the number
+   of elements as defined by the subscript expression.
+   CALL_COUNT is used to determine if we are calling the function once, e.g.
+   we are working on the current dimension of ARRAY, or if we are calling
+   the function repeatedly.  In the later case we need to take elements
+   from the TARGET_TYPE of ARRAY.
+   With a CALL_COUNT greater than 1 we calculate the offsets for every element
+   that should be in the result array.  Then we fetch the contents and then
+   copy them into the result array.  The result array will have one dimension
+   less than the input array, so later on we need to recreate the indices and
+   ranges in the calling function.  */
+
+struct value *
+value_slice_1 (struct value *array, int lowbound, int length, int call_count)
+{
   struct type *slice_range_type, *slice_type, *range_type;
-  LONGEST lowerbound, upperbound;
-  struct value *slice;
-  struct type *array_type;
+  struct type *array_type = check_typedef (value_type (array));
+  struct type *elt_type = check_typedef (TYPE_TARGET_TYPE (array_type));
+  unsigned int elt_size, elt_offs;
+  LONGEST ary_high_bound, ary_low_bound;
+  struct value *v;
+  int slice_range_size, i = 0, row_count = 1, elem_count = 1;
 
-  array_type = check_typedef (value_type (array));
+  /* Check for legacy code if we are actually dealing with an array or
+     string.  */
   if (TYPE_CODE (array_type) != TYPE_CODE_ARRAY
       && TYPE_CODE (array_type) != TYPE_CODE_STRING)
     error (_("cannot take slice of non-array"));
 
-  range_type = TYPE_INDEX_TYPE (array_type);
-  if (get_discrete_bounds (range_type, &lowerbound, &upperbound) < 0)
-    error (_("slice from bad array or bitstring"));
+  ary_low_bound = TYPE_LOW_BOUND (TYPE_INDEX_TYPE (array_type));
+  ary_high_bound = TYPE_HIGH_BOUND (TYPE_INDEX_TYPE (array_type));
+
+  /* When we are working on a multi-dimensional array, we need to get the
+     attributes of the underlying type.  */
+  if (call_count > 1)
+    {
+      elt_type = check_typedef (TYPE_TARGET_TYPE (elt_type));
+      row_count = TYPE_LENGTH (array_type)
+		    / TYPE_LENGTH (TYPE_TARGET_TYPE (array_type));
+    }
+
+  elem_count = length;
+  elt_size = TYPE_LENGTH (elt_type);
+  elt_offs = longest_to_int (lowbound - ary_low_bound);
+
+  elt_offs *= elt_size;
+
+  /* Check for valid user input.  In case of Fortran this was already done
+     in the calling function.  */
+  if (call_count == 1
+	&& (!TYPE_ARRAY_UPPER_BOUND_IS_UNDEFINED (array_type)
+	      && elt_offs >= TYPE_LENGTH (array_type)))
+    error (_("no such vector element"));
 
-  if (lowbound < lowerbound || length < 0
-      || lowbound + length - 1 > upperbound)
-    error (_("slice out of range"));
+  /* CALL_COUNT is 1 when we are dealing either with the highest dimension
+     of the array, or a one dimensional array.  Set RANGE_TYPE accordingly.
+     In both cases we calculate how many rows/elements will be in the output
+     array by setting slice_range_size.  */
+  if (call_count == 1)
+    {
+      range_type = TYPE_INDEX_TYPE (array_type);
+      slice_range_size = elem_count;
+
+      /* Check if the array bounds are valid.  */
+      if (get_discrete_bounds (range_type, &ary_low_bound, &ary_high_bound) < 0)
+	error (_("slice from bad array or bitstring"));
+    }
+  /* When CALL_COUNT is greater than 1, we are dealing with an array of arrays.
+     So we need to get the type below the current one and set the RANGE_TYPE
+     accordingly.  */
+  else
+    {
+      range_type = TYPE_INDEX_TYPE (TYPE_TARGET_TYPE (array_type));
+      slice_range_size = (ary_low_bound + row_count - 1) * (elem_count);
+      ary_low_bound = TYPE_LOW_BOUND (range_type);
+    }
 
   /* FIXME-type-allocation: need a way to free this type when we are
-     done with it.  */
-  slice_range_type = create_static_range_type ((struct type *) NULL,
-					       TYPE_TARGET_TYPE (range_type),
-					       lowbound,
-					       lowbound + length - 1);
+      done with it.  */
 
+  slice_range_type = create_static_range_type (NULL, TYPE_TARGET_TYPE (range_type),
+					       ary_low_bound, slice_range_size);
   {
-    struct type *element_type = TYPE_TARGET_TYPE (array_type);
-    LONGEST offset
-      = (lowbound - lowerbound) * TYPE_LENGTH (check_typedef (element_type));
+    struct type *element_type;
+
+    /* When CALL_COUNT equals 1 we can use the legacy code for subarrays.  */
+    if (call_count == 1)
+      {
+	element_type = TYPE_TARGET_TYPE (array_type);
 
-    slice_type = create_array_type ((struct type *) NULL,
-				    element_type,
-				    slice_range_type);
-    TYPE_CODE (slice_type) = TYPE_CODE (array_type);
+	slice_type = create_array_type (NULL, element_type, slice_range_type);
+
+	TYPE_CODE (slice_type) = TYPE_CODE (array_type);
+
+	if (VALUE_LVAL (array) == lval_memory && value_lazy (array))
+	  v = allocate_value_lazy (slice_type);
+	else
+	  {
+	    v = allocate_value (slice_type);
+	    value_contents_copy (v,
+				 value_embedded_offset (v),
+				 array,
+				 value_embedded_offset (array) + elt_offs,
+				 elt_size * longest_to_int (length));
+	  }
 
-    if (VALUE_LVAL (array) == lval_memory && value_lazy (array))
-      slice = allocate_value_lazy (slice_type);
+      }
+    /* When CALL_COUNT is larger than 1 we are working on a range of ranges.
+       So we copy the relevant elements into the new array we return.  */
     else
       {
-	slice = allocate_value (slice_type);
-	value_contents_copy (slice, 0, array, offset,
-			     type_length_units (slice_type));
+	LONGEST dst_offset = 0;
+	LONGEST src_row_length = TYPE_LENGTH (TYPE_TARGET_TYPE (array_type));
+
+	element_type = TYPE_TARGET_TYPE (TYPE_TARGET_TYPE (array_type));
+	slice_type = create_array_type (NULL, element_type, slice_range_type);
+
+	TYPE_CODE (slice_type) = TYPE_CODE (TYPE_TARGET_TYPE (array_type));
+
+	v = allocate_value (slice_type);
+	for (i = 0; i < longest_to_int (row_count); i++)
+	  {
+	    /* Fetches the contents of ARRAY and copies them into V.  */
+	    value_contents_copy (v,
+				 dst_offset,
+				 array,
+				 elt_offs,
+				 elt_size * elem_count);
+	    elt_offs += src_row_length;
+	    dst_offset += elt_size * elem_count;
+	  }
       }
 
-    set_value_component_location (slice, array);
-    VALUE_FRAME_ID (slice) = VALUE_FRAME_ID (array);
-    set_value_offset (slice, value_offset (array) + offset);
+    set_value_component_location (v, array);
+    VALUE_REGNUM (v) = VALUE_REGNUM (array);
+    VALUE_FRAME_ID (v) = VALUE_FRAME_ID (array);
+    set_value_offset (v, value_offset (array) + elt_offs);
   }
 
-  return slice;
+  return v;
 }
 
 /* Create a value for a FORTRAN complex number.  Currently most of the
diff --git a/gdb/value.h b/gdb/value.h
index 0b417b4..4086a77 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -1057,6 +1057,8 @@ extern struct value *varying_to_slice (struct value *);
 
 extern struct value *value_slice (struct value *, int, int);
 
+extern struct value *value_slice_1 (struct value *, int, int, int);
+
 extern struct value *value_literal_complex (struct value *, struct value *,
 					    struct type *);