[PATCH]: Tracking and reporting uninitialized variables

[Caroline Tice]

As part of some work I have been doing on improving debugging of  
optimized code, I
have created a GCC patch that tags variables it believes are  
uninitialized with a new
Dwarf op (an extension), DW_OP_GNU_uninit.   I have submitted that  
patch to the
GCC patches list and am waiting for approval to commit it.   I have  
also created the
following gdb patch to recognize the new op and inform the user when a  
variable
the user requests to see is uninitialized.

I have tested this patch on some small testcases and I have run the  
gdb dejagnu
testsuite with no regressions.  I am new to submitting things to this  
list, so if there
is anything else I ought to have done, please let me know (kindly!).

Is this patch okay to commit to gdb?

-- Caroline Tice
ctice@apple.com



2007-05-01  Caroline Tice  <ctice@apple.com>

         * c-valprint.c (c_value_print):  If the var_status field of the
         value struct is 0, print out "[uninitialized]" before the  
value.
         * dwarf2expr.c (add_piece): Make function non-static.
         (unsigned_address_type): Likewise.
         (signed_address_type): Likewise.
         (execute_stack_op): Initialize ctx->var_status 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->var_status appropriately.
         * dwarf2expr.h (struct dwarf_expr_context): New field,  
var_status.
         (unsigned_address_type): Add extern declaration.
         (signed_address_type): Likewise.
         (add_piece): Likewise.
         * dwarf2loc.c (dwarf2_evaluate_loc_desc): Add call to
         set_var_status.
         * 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, var_status.
         (allocate_value): Initialize new field.
         (set_var_status): New function.
         (value_var_status): New function.
         * value.h (value_var_status): New extern declaration.
         (set_var_status): Likewise.
         * include/elf/dwarf2.h: (enum dwarf_location_atom): Add new  
DW_OP,
         DW_OP_GNU_uninit.


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