* dwarf2read.c (read_subrange_type): Handle missing base type

	according to Dwarf-2 specifications.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4fe625b2509d1f74be9854facdc4414d0ac914ab..16b58015093d602056d9d9ef23e2a09d75a8c7b3 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2010-06-02  Pierre Muller  <muller@ics.u-strasbg.fr>
+
+       * dwarf2read.c (read_subrange_type): Handle missing base type
+       according to Dwarf-2 specifications.
+
 2010-06-01  Sergio Durigan Junior  <sergiodj@redhat.com>
 
        * expprint.c (print_subexp_standard): Remove exp_opcodes BINOP_INCL,

diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 254d8999b7ba43fa23d85844fa9f6fb784389b71..da895737dced49979f7cc738e6ab157d4b038224 100644 (file)
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -6131,16 +6131,8 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
   LONGEST high = -1;
   char *name;
   LONGEST negative_mask;
-  
+
   base_type = die_type (die, cu);
-  if (TYPE_CODE (base_type) == TYPE_CODE_VOID)
-    {
-      complaint (&symfile_complaints,
-                _("DW_AT_type missing from DW_TAG_subrange_type"));
-      base_type
-       = init_type (TYPE_CODE_INT, gdbarch_addr_bit (gdbarch) / 8,
-                    0, NULL, cu->objfile);
-    }
 
   if (cu->language == language_fortran)
     { 
@@ -6158,10 +6150,10 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
   attr = dwarf2_attr (die, DW_AT_upper_bound, cu);
   if (attr)
     {       
-      if (attr->form == DW_FORM_block1)
+      if (attr->form == DW_FORM_block1 || is_ref_attr (attr))
         {
           /* GCC encodes arrays with unspecified or dynamic length
-             with a DW_FORM_block1 attribute.
+             with a DW_FORM_block1 attribute or a reference attribute.
              FIXME: GDB does not yet know how to handle dynamic
              arrays properly, treat them as arrays with unspecified
              length for now.
@@ -6176,6 +6168,54 @@ read_subrange_type (struct die_info *die, struct dwarf2_cu *cu)
       else
         high = dwarf2_get_attr_constant_value (attr, 1);
     }
+  else
+    {
+      attr = dwarf2_attr (die, DW_AT_count, cu);
+      if (attr)
+       {
+         int count = dwarf2_get_attr_constant_value (attr, 1);
+         high = low + count - 1;
+       }
+    }
+
+  /* Dwarf-2 specifications explicitly allows to create subrange types
+     without specifying a base type.
+     In that case, the base type must be set to the type of
+     the lower bound, upper bound or count, in that order, if any of these
+     three attributes references an object that has a type.
+     If no base type is found, the Dwarf-2 specifications say that
+     a signed integer type of size equal to the size of an address should
+     be used.
+     For the following C code: `extern char gdb_int [];'
+     GCC produces an empty range DIE.
+     FIXME: muller/2010-05-28: Possible references to object for low bound,
+     high bound or count are not yet handled by this code.
+  */
+  if (TYPE_CODE (base_type) == TYPE_CODE_VOID)
+    {
+      struct objfile *objfile = cu->objfile;
+      struct gdbarch *gdbarch = get_objfile_arch (objfile);
+      int addr_size = gdbarch_addr_bit (gdbarch) /8;
+      struct type *int_type = objfile_type (objfile)->builtin_int;
+
+      /* Test "int", "long int", and "long long int" objfile types,
+        and select the first one having a size above or equal to the
+        architecture address size.  */
+      if (int_type && TYPE_LENGTH (int_type) >= addr_size)
+       base_type = int_type;
+      else
+       {
+         int_type = objfile_type (objfile)->builtin_long;
+         if (int_type && TYPE_LENGTH (int_type) >= addr_size)
+           base_type = int_type;
+         else
+           {
+             int_type = objfile_type (objfile)->builtin_long_long;
+             if (int_type && TYPE_LENGTH (int_type) >= addr_size)
+               base_type = int_type;
+           }
+       }
+    }
 
   negative_mask = 
     (LONGEST) -1 << (TYPE_LENGTH (base_type) * TARGET_CHAR_BIT - 1);