Designs for better debug info in GCC

[Robert Dewar]

Andrew Haley wrote:
=
>  > I don't think it is fine, we have constant complaints from our
>  > users about this. I think we definitely need an optimization
>  > level that avoids this.
> 
> Short of putting a barrier at every sequence point, how would you stop
> the debugger from jumping all over the place?  I'm assuming that you
> do want the debugger to show what is actually going on, not fake it.

Note that putting a barrier at every sequence point is exactly what
Geert proposed, and I think we really need an optimization level
that does the equivalent of this. It is also needed for effective
source-object traceability for certification purposes. Yes, you
can use -O0, but the trouble is that we generate so much rubbish
at this level, much worse than commpetitive compilers with "optimization
off", and the shear amount of object code makes the traceability
analysis harder (and makes executables unnecessarily huge).
> 
> Andrew.
>