[Bug symtab/10002] New: extern optimized out symbols print: Address of symbol is unknown.

[Bug symtab/10002] New: extern optimized out symbols print: Address of symbol is unknown.

[jan dot kratochvil at redhat dot com]

Testcase:
------------------------------------------------
extern int missing;

int
main (void)
{
  return 0 && missing;
}
------------------------------------------------
gcc -o kfail kfail.c -Wall -g
gcc-4.3.2-7.x86_64 (Fedora 10)

produces:
 <1><55>: Abbrev Number: 4 (DW_TAG_variable)
    <56>   DW_AT_name        : (indirect string, offset: 0x66): missing	
    <5c>   DW_AT_type        : <0x4e>	
    <60>   DW_AT_external    : 1	
    <61>   DW_AT_declaration : 1	

and GDB prints:
GNU gdb (GDB) 6.8.50.20090324-cvs
(gdb) p missing
Address of symbol "missing" is unknown.

It should print:
(gdb) p missing
$1 = <value optimized out>

Filing only to get a number for KFAIL, it was discussed at:
http://sourceware.org/ml/gdb-patches/2009-03/threads.html#00282

-- 
           Summary: extern optimized out symbols print: Address of symbol is
                    unknown.
           Product: gdb
           Version: unknown
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: symtab
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: jan dot kratochvil at redhat dot com
                CC: gdb-prs at sourceware dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=10002

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.

[Bug symtab/10002] extern optimized out symbols print: Address of symbol is unknown.

[jan dot kratochvil at redhat dot com]

------- Additional Comments From jan dot kratochvil at redhat dot com  2009-03-26 14:23 -------
As there is DW_AT_declaration present according to the DWARF spec such DIE
cannot represent an <optimized out> variable:
DWARF3 4.1 point 4:
# In a variable entry representing the definition of a variable (that is, with
# no DW_AT_declaration attribute) if no location attribute is present [...],
# the variable is assumed to exist in the source code but not in the executable
# program [...]

Currently the compiler cannot optimize out variables referenced from other
compilation units.

Discussed at:
http://sourceware.org/ml/gdb/2009-03/threads.html#00159


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://sourceware.org/bugzilla/show_bug.cgi?id=10002

------- You are receiving this mail because: -------
You are on the CC list for the bug, or are watching someone who is.