type: add c99 variable length array support

The dwarf standard allow certain attributes to be expressed as dwarf
expressions rather than constants. For instance upper-/lowerbound attributes.
In case of a c99 variable length array the upperbound is a dynamic attribute.

With this change c99 vla behave the same as with static arrays.

1| void foo (size_t n) {
2|   int ary[n];
3|   memset(ary, 0, sizeof(ary));
4| }

(gdb) print ary
$1 = {0 <repeats 42 times>}

	* dwarf2loc.c (dwarf2_locexpr_baton_eval): New function.
	(dwarf2_evaluate_property): New function.
	* dwarf2loc.h (dwarf2_evaluate_property): New function prototype.
	* dwarf2read.c (attr_to_dynamic_prop): New function.
	(read_subrange_type): Use attr_to_dynamic_prop to read high bound
	attribute.
	* gdbtypes.c: Include dwarf2loc.h.
	(is_dynamic_type): New function.
	(resolve_dynamic_type): New function.
	(resolve_dynamic_bounds): New function.
	(get_type_length): New function.
	(check_typedef): Use get_type_length to compute type length.
	* gdbtypes.h (TYPE_HIGH_BOUND_KIND): New macro.
	(TYPE_LOW_BOUND_KIND): New macro.
	(is_dynamic_type): New function prototype.
	* value.c (value_from_contents_and_address): Call resolve_dynamic_type
	to resolve dynamic properties of the type. Update comment.
	* valops.c (get_value_at, value_at, value_at_lazy): Update comment.

1 files changed, 28 insertions, 0 deletions

diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
index 786e77c..36173c5 100644
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -90,6 +90,14 @@ struct value *dwarf2_evaluate_loc_desc (struct type *type,
 					size_t size,
 					struct dwarf2_per_cu_data *per_cu);
 
+/* Converts a dynamic property into a static one.  ADDR is the address of
+   the object currently being evaluated and might be nedded.
+   Returns 1 if PROP could be converted and the static value is passed back
+   into VALUE, otherwise returns 0.  */
+
+int dwarf2_evaluate_property (const struct dynamic_prop *prop,
+			      CORE_ADDR addr, CORE_ADDR *value);
+
 CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
 				  unsigned int addr_index);
 
@@ -135,6 +143,26 @@ struct dwarf2_loclist_baton
   unsigned char from_dwo;
 };
 
+/* A dynamic property is either expressed as a single location expression
+   or a location list.  If the property is an indirection, pointing to
+   another die, keep track of the targeted type in REFERENCED_TYPE.  */
+
+struct dwarf2_property_baton
+{
+  /* If the property is an indirection, we need to evaluate the location
+     LOCEXPR or LOCLIST in the context of the type REFERENCED_TYPE.
+     If NULL, the location is the actual value of the property.  */
+  struct type *referenced_type;
+  union
+  {
+    /* Location expression.  */
+    struct dwarf2_locexpr_baton locexpr;
+
+    /* Location list to be evaluated in the context of REFERENCED_TYPE.  */
+    struct dwarf2_loclist_baton loclist;
+  };
+};
+
 extern const struct symbol_computed_ops dwarf2_locexpr_funcs;
 extern const struct symbol_computed_ops dwarf2_loclist_funcs;