Bogus DWARF line#/address

[Allen Hopkins]

No, no optimization options.  Just -ggdb, -Wno-deprecated.
I understand the "-O0" (oh-zero) is the same as no -O at all.
But I'll try it.  I'm pretty desparate for ideas.

-Allen

Eljay Love-Jensen wrote:

> Hi Allen,
> 
> Was the code compiled with -O0?
> 
> --Eljay
> 
> > I'm trying to use gdb to debug code compiled with g++
> > (3.4.3) from .cpp source files that have, in turn, been
> > compiled from higher-level source code by a special
> > compiler we're developing here called Metropolis.
> > 
> > Metropolis source files have .mmm extensions, and there is
> > a .cpp file generated for each one.  #line directives are
> > inserted in the .cpp files so gdb can display the .mmm
> > source, and breakpoints can be set in terms of lines in the
> > .mmm files.
> > 
> > The problem: Sometimes setting a breakpoint at a .mmm file
> > line results in a breakpoint at an absurd place, unrelated
> > to the desired line.
> > 
> > I ran "readelf -wl" on the executable to see what addresses
> > are being associated with what lines of code in the DWARF-2
> > output.  The results are interesting:
> > 
> > readelf shows that line 42 of P.mmm, where I want to set my
> > breakpoint & can't, first gets one address associated
> > with it (the wrong one, where my breakpoint really ends up).
> > Then, further down in the output, it shows it getting the
> > right one.  (The wrong one is the address of the destructor
> > of some class in the application.)
> > 
> > I've posted the relevant files here, at 
> > http://www.eecs.berkeley.edu/~allenh/bogus_dwarf.
> > READ_ME.txt tells what to look for & where.
> > 
> > Any help or suggestions with this would be greatly
> > appreciated.  I don't understand how g++ works enough to
> > make sense of it.
> > 
> >     g++ is version 3.4.3
> >     uname -a says:
> >     Linux hig.eecs.berkeley.edu 2.6.7-1.494.2.2smp #1 SMP Tue Aug 3 09:59:49 EDT 2004 i686 i686 i386 GNU/Linux
> > 
> > -Allen Hopkins