Designs for better debug info in GCC

[Ian Lance Taylor]

Janis Johnson <janis187@us.ibm.com> writes:

> On Wed, 2007-12-19 at 10:00 -0800, Ian Lance Taylor wrote:
> > One way to make a principled choice is to consider the line notes we
> > are going to emit with the debugging information.  Presumably we do
> > not have the goal of emitting correct debug information in between
> > line notes--e.g., when using the "stepi" command in gdb.  Our goal is
> > to emit correct debug information at the points where a debugger would
> > naturally stop--the notes for where a line starts.
> 
> Debugging in between line notes is important for core files and
> when moving up and down the call stack, so at such locations the
> debugger needs to at least know whether debug information is
> reliable or not.

For some things, sure, but we are just talking about the values in
user visible variables stored in registers.  There is no way we can
make that information be correct between line notes.

Ian