[lto] PATCH: fix bug w/ missing type attribute

[Sandra Loosemore <sandra at codesourcery dot com>]

Because DWARF doesn't have an explicit encoding of the void type, in some cases 
a missing type attribute is used to represent void and needs to be checked for 
explicitly.  Last week I checked in a patch to fix the same problem in 
lto_read_pointer_reference_type_DIE and lto_read_const_volatile_restrict_DIE, 
and I just realized I missed the typedef case.  This is already committed as 
"obvious".

-Sandra


2006-10-11  Sandra Loosemore  <sandra@codesourcery.com>

	* gcc/lto/lto.c (lto_read_typedef_DIE): Treat missing type attribute
	as void instead of error, for compatibility with dwarf2out.c behavior.

Index: gcc/lto/lto.c
===================================================================
*** gcc/lto/lto.c	(revision 117637)
--- gcc/lto/lto.c	(working copy)
*************** lto_read_typedef_DIE (lto_info_fd *fd,
*** 2434,2442 ****
      }
    LTO_END_READ_ATTRS ();
  
!   /* The DW_AT_type and DW_AT_name attributes are required.  */
!   if (!base_type || !name)
      lto_file_corrupt_error ((lto_fd *)fd);
    /* Build the typedef.  */
    type = build_variant_type_copy (base_type);
    decl = build_decl (TYPE_DECL, name, type);
--- 2434,2449 ----
      }
    LTO_END_READ_ATTRS ();
  
!   /* The DW_AT_name attribute is required.  */
!   if (!name)
      lto_file_corrupt_error ((lto_fd *)fd);
+   /* The DW_AT_type attribute is supposed to be required, but since DWARF
+      has no representation for the void type, dwarf2out.c omits the type
+      attribute in that case.  So, in order to allow GCC's output to be
+      read in again, we have to interpret a missing base type attribute as
+      the void type, too.  */
+   if (!base_type)
+     base_type = void_type_node;
    /* Build the typedef.  */
    type = build_variant_type_copy (base_type);
    decl = build_decl (TYPE_DECL, name, type);