[Bug gdb/11704] New: Cannot load debugging info

[Bug gdb/11704] New: Cannot load debugging info

[dimabarts at yahoo dot com]

gdb doesn't load debugging info. Here is my session:
% cc -g -c hello.c
% cc hello.o -o hello
% ~/gdb-7.1/gdb/gdb hello
GNU gdb (GDB) 7.1
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "sparc-sun-solaris2.10".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /export/home/dbarts/C/hello...(no debugging symbols
found)...done.

Trying symbol-file hello.o doesn't work either

However when I compile and link in the same move, everything suddenly works:
% cc -g hello.c -o hello
% ~/gdb-7.1/gdb/gdb hello
GNU gdb (GDB) 7.1
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "sparc-sun-solaris2.10".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /export/home/dbarts/C/hello...done.

The same happens with version 6.8. Both were built with the Sun compiler Sun C 5.5.

-- 
           Summary: Cannot load debugging info
           Product: gdb
           Version: 7.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: gdb
        AssignedTo: unassigned at sourceware dot org
        ReportedBy: dimabarts at yahoo dot com
                CC: gdb-prs at sourceware dot org


http://sourceware.org/bugzilla/show_bug.cgi?id=11704

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[Bug gdb/11704] Cannot load debugging info

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2010-06-14 20:58 -------
> % cc hello.o -o hello

Try changing that to:

cc hello.o -g -o hello

I think you need -g on the link line to tell the linker to preserve debuginfo.

You can always check gdb here by using readelf or something like that to
see if the executable does in fact have debuginfo.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at redhat dot com
             Status|UNCONFIRMED                 |WAITING


http://sourceware.org/bugzilla/show_bug.cgi?id=11704

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[Bug gdb/11704] Cannot load debugging info

[dimabarts at yahoo dot com]

------- Additional Comments From dimabarts at yahoo dot com  2010-06-14 21:22 -------
(In reply to comment #1)
> > % cc hello.o -o hello
> 
> Try changing that to:
> 
> cc hello.o -g -o hello
> 
> I think you need -g on the link line to tell the linker to preserve debuginfo.
> 
> You can always check gdb here by using readelf or something like that to
> see if the executable does in fact have debuginfo.

Thanks but no dice...

% cc hello.o -g -o hello
% ~/gdb-7.1/gdb/gdb hello
Reading symbols from /export/home/dbarts/C/hello...Can't read symbols from
/export/home/dbarts/C/hello: Invalid operation

I've checked man ld and the flag -g isn't mentioned at all (although there's the
opposite one, -s). Here's another experiment - without any executables:
% ~/gdb-7.1/gdb/gdb
(gdb) symbol-file hello.o
Reading symbols from /export/home/dbarts/C/hello.o...(no debugging symbols
found)...done.

But there is dbg info:
% ls -l hello.o
-rw-r--r--   1 dbarts   staff       1040 Jun 14 14:18 hello.o
% strip hello.o
% ls -l hello.o
-rw-r--r--   1 dbarts   staff        760 Jun 14 17:15 hello.o

So 25% of original hello.o had consisted of dbg info.

-- 


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[Bug gdb/11704] Cannot load debugging info

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2010-06-15 21:46 -------
(In reply to comment #2)
> Reading symbols from /export/home/dbarts/C/hello...Can't read symbols from
> /export/home/dbarts/C/hello: Invalid operation

This is a different error message than the first time.
For this one it would be interesting to see what is happening inside gdb
when this error is printed.

AFAIK you can't generally use symbol-file with a .o.


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[Bug gdb/11704] Cannot load debugging info

[dimabarts at yahoo dot com]

------- Additional Comments From dimabarts at yahoo dot com  2010-06-16 00:35 -------
> For this one it would be interesting to see what is happening inside gdb

I don't know how to look inside gdb as I don't have a working debugger. (If I had dbx I'd just use that)

> AFAIK you can't generally use symbol-file with a .o.

Not sure what symbol-file is for then. Certainly didn't work with the source .c file.

Has anyone actually tested dbx when it's compiled via Sun's cc as opposed to gcc? I have gcc 2.8.1 (and 
building dbx has failed quite miserably), is it worth installing a newer version? Is it possible that there's 
a gdb binary for solaris 10 somewhere so I won't have to build from source?


(In reply to comment #3)
> (In reply to comment #2)
> > Reading symbols from /export/home/dbarts/C/hello...Can't read symbols from
> > /export/home/dbarts/C/hello: Invalid operation
> 
> This is a different error message than the first time.
> For this one it would be interesting to see what is happening inside gdb
> when this error is printed.
> 
> AFAIK you can't generally use symbol-file with a .o.
> 

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[Bug gdb/11704] Cannot load debugging info

[dimabarts at yahoo dot com]

------- Additional Comments From dimabarts at yahoo dot com  2010-06-16 17:38 -------
(In reply to comment #4)
I meant gdb above of course, not dbx.

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[Bug gdb/11704] Cannot load debugging info

[tromey at redhat dot com]

------- Additional Comments From tromey at redhat dot com  2010-06-17 17:03 -------
(In reply to comment #4)
> > For this one it would be interesting to see what is happening inside gdb
> 
> I don't know how to look inside gdb as I don't have a working debugger. (If I
had dbx I'd just use that)

In this case you could probably use strace to see what system call is failing.
That might help, anyway.
 
> > AFAIK you can't generally use symbol-file with a .o.
> 
> Not sure what symbol-file is for then. Certainly didn't work with the source
.c file.

I think it is there to support the case where the inferior process does
not have debug symbols, but you have an unstripped executable as well.


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