vla: support for DW_AT_count

This patch adds support for DW_AT_count as requested in the code review:

  https://sourceware.org/ml/gdb-patches/2013-11/msg00200.html

gdb/ChangeLog:

	* dwarf2read.c (read_subrange_type): Convert DW_AT_count to a dynamic
	property and store it as the high bound and flag the range accordingly.
	* gdbtypes.c (resolve_dynamic_bounds): If range is flagged as
	RANGE_UPPER_BOUND_IS_COUNT assign low + high - 1 as the new high bound.
	* gdbtypes.h (enum range_flags): New enum.
	(struct range_bounds): Add flags member.

1 files changed, 10 insertions, 8 deletions

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index ff66cce..7c64491 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -14493,6 +14493,7 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
   struct attribute *attr;
   struct dynamic_prop low, high;
   int low_default_is_valid;
+  int high_bound_is_count = 0;
   const char *name;
   LONGEST negative_mask;
 
@@ -14559,15 +14560,13 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
   if (!attr_to_dynamic_prop (attr, die, cu, &high))
     {
       attr = dwarf2_attr (die, DW_AT_count, cu);
-      if (attr)
-	{
-	  int count = dwarf2_get_attr_constant_value (attr, 1);
-	  high.data.const_val = low.data.const_val + count - 1;
-	}
-      else
+      if (attr_to_dynamic_prop (attr, die, cu, &high))
 	{
-	  /* Unspecified array length.  */
-	  high.data.const_val = low.data.const_val - 1;
+	  /* If bounds are constant do the final calculation here.  */
+	  if (low.kind == PROP_CONST && high.kind == PROP_CONST)
+	    high.data.const_val = low.data.const_val + high.data.const_val - 1;
+	  else
+	    high_bound_is_count = 1;
 	}
     }
 
@@ -14627,6 +14626,9 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
 
   range_type = create_range_type (NULL, orig_base_type, &low, &high);
 
+  if (high_bound_is_count)
+    TYPE_RANGE_DATA (range_type)->flag_upper_bound_is_count = 1;
+
   /* Ada expects an empty array on no boundary attributes.  */
   if (attr == NULL && cu->language != language_ada)
     TYPE_HIGH_BOUND_KIND (range_type) = PROP_UNDEFINED;