Re: gdb 5.3 issues with g++ 3.2 on RedHat 7.3 & Solaris 9.

[Daniel Jacobowitz <drow at mvista dot com>]

On Mon, Dec 23, 2002 at 05:39:43PM -0500, Joshua D. Marantz wrote:
> Hello,
> 
> We are having trouble debugging C++ code.  Are there a number of
> outstanding issues

Hundreds, I sometimes think.

> gdb 5.2.1, gdb 5.3
> g++ 3.1.1, 3.2, 3.2.1
> g++ compile options "-g", "-g3", "-ggdb", "-gstabs", "-gstabs+", "-gdwarf-2"
> SGI STL & STLport 4.5.3
> RedHat 7.3 & Solaris 9

I highly recommend using just -g and GCC 3.2.1; that'll give you
DWARF-2.  -g3 is also good.

> Symptoms include:
> 
>  - breakpoints in constructors do not work.  gdb says they get set successfully,
>    but they do not actually break.  This occurs whether the constructors are
>    inline or out-of-line.

This generally works, although with DWARF-2 it's dodgy.  The problem is
well understood and I haven't completely made up my mind what to do
about it yet.

>  - casting on the command line does not work -- yields a syntax error

Never seen this; there are problems with naming types that might be
causing it, I suppose...

>  - printing contents of instances of STL classes sometimes crashes

This should not happen in GDB 5.3.

>  - frequent gdb crashes (sorry this is so vague...)

Nor should this, although I know of at least one (calling functions in
a breakpoint's command list isn't fixed yet).

>  - when compiling with -gstabs+, I can print most structures, but I can't
>    call class methods from gdb.
>  - when compiling with -gdwarf-2, I can call class methods from gdb, but I can't
>    print most structures

OK, that's really odd.

>  - calling global functions from the debugger takes a long time and uses
>    a lot of memory.  calling class methods is fast however.  

I swear I'd resolved this.  Must be a new problem.

>  - it is difficult to call template methods from the debugger

Yes.

> All these issues were not present using g++ 2.8.1 and gdb 4.17.  In
> that environment most things worked well  Although gdb 4.17 did crash
> a little too often, it was much more functional.

It had nothing to do with GDB.  C++ was a simpler thing, then.  A lot
simpler.

> We can't go back to those old tools because our C++ & STL usage goes
> beyond the capabilities of g++ 2.8.1 & 2.9.*.
> 
> I can give testcases for all these things but it's really pretty
> basic C++ debugging.
> 
> Is this enough information?  Is there a path through these tools that
> works -- e.g. config options, versions, etc?

I'd appreciate small testcases for every one of these problems, if you
can manage it.  We'll see what we can do.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer