debug/1621: Debugging with complex numbers

[Daniel Jacobowitz]

The following reply was made to PR debug/1621; it has been noted by GNATS.

From: Daniel Jacobowitz <drow@mvista.com>
To: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
Cc: "Joseph S. Myers" <jsm28@cam.ac.uk>, bangerth@dealii.org,
	gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Subject: Re: debug/1621: Debugging with complex numbers
Date: Sat, 7 Dec 2002 20:21:24 -0500

 On Thu, Dec 05, 2002 at 06:09:46PM -0600, Wolfgang Bangerth wrote:
 > 
 > 
 > > >     Joseph, this report is now almost 2 years old, and versions
 > > >     3.0 and 3.1/2 have happened in between. Unfortunately, there
 > > >     are no testcases in the report, so I can't check the claims
 > > >     myself, but do you know whether the situation has or has
 > > >     not improved in the meantime?
 > > 
 > > The testcase is at the URL given in the report 
 > > <http://gcc.gnu.org/ml/gcc/2000-12/msg00536.html>:
 > 
 > Oh, sorry, I seem to have overlooked this. 
 > 
 > 
 > >         static __complex__ double x = 2.0 + 3.0i;
 > >         int main(void)
 > >         {
 > >           return 0;
 > >         }
 > > 
 > > (gdb) p x
 > > $1 = Invalid C/C++ type code 20 in symbol table.
 > > (gdb) p x$real
 > > No symbol "x$real" in current context.
 > > (gdb) p x$imag
 > > No symbol "x$imag" in current context.
 > 
 > This is also the behavior I get, using 3.3CVS and gdb5.1.1. For some 
 > reason, I cannot get gdb CVS compiled, so can't check whether it works 
 > now. The gdb error message indicates that gcc is doing something but gdb 
 > isn't understanding it.
 > 
 > Daniel, I'm CC:ing you since you wrote the latest mail I could find on the 
 > gdb mailing lists that is about complex value support 
 >   http://sources.redhat.com/ml/gdb/2002-01/msg00359.html
 > 
 > In this you state that you had been fixing some problems. Do you know 
 > anything about gdb's present support for complex values?
 
 GDB is fine; GCC is broken.  You'll find that in recent GCC and GDB
 DWARF-2 will work fine.  Stabs will fail; the debugging output from GCC
 is inconsistent.
 
 Someone should probably fix it to use the Sun notation for such
 variables (i.e. "R" instead of "r", IIRC).
 
 -- 
 Daniel Jacobowitz
 MontaVista Software                         Debian GNU/Linux Developer