Okay, here is the modified patch.  I went back and double
checked  the variable tracking stuff in GCC and discovered
that there is NOT a way to mark individual pieces in a multi-piece
location expression as initialized or not; it's one initialized value  
for
the whole thing.  Therefore I did not add the initialized field to
the dwarf_expr_piece as suggested below.  But I did address
everything else.

I tested it by running it on a small test case I have
(with DW_OP_GNU_uninit ops in it), as well as running the
dejagnu testsuite with no regressions.  Is this modified patch okay
to commit to FSF GDB?

-- Caroline Tice
ctice@apple.com

2007-05-09  Caroline Tice  <ctice@apple.com>

         * c-valprint.c (c_value_print):  If the initialized field of  
the
         value struct is 0, print out "[uninitialized]" before the  
value.
         * dwarf2expr.c (execute_stack_op): Initialize ctx- 
 >initialized field;
         allow DW_OP_GNU_uninit as legal op following a DW_OP_reg op  
or a
         DW_OP_regx op; add case for DW_OP_GNU_uninit and update
         ctx->initialized appropriately. Verify no location op follows
         DW_OP_GNU_uninit.
         * dwarf2expr.h (struct dwarf_expr_context): New field,  
initialized.
         * dwarf2loc.c (dwarf2_evaluate_loc_desc): Add call to
         set_value_initialized.
         * dwarf2read.c (dwarf_stack_op_name): Add case for  
DW_OP_GNU_uninit.
         (decode_locdesc): Add case for DW_OP_GNU_uninit.
         * value.c (struct value):  New field, initialized.
         (allocate_value): Initialize new field.
         (set_value_initialized): New function.
         (value_initialized): New function.
         * value.h (value_initialized): New extern declaration.
         (set_value_initialized): Likewise.
         * include/elf/dwarf2.h: (enum dwarf_location_atom): Add new  
DW_OP,
         DW_OP_GNU_uninit.