On Wed, Jan 18, 2023 at 05:25:10PM +0100, Jan Hubicka wrote:
> > On Jan 18 2023, Michael Matz wrote:
> >
> > > The purest solution is to emit unwind tables for all functions that
> > > request it into .eh_frame and for those that don't request it put
> > > into .debug_frame (if also -g is on).
> >
> > The assembler does not allow switching back to .eh_frame once a
> > different format has been chosen, so .eh_frame must be either on or off
> > all the way through.
>
> This is unforutnate (and I did not noticed this earlier).
> Would it be hard to fix assembler? In general situations like this can
> be handled by forced partitioning in GCC, but it is not a good solution
> since we want to keep partitioning algorithm an optional step by design.
If it was just about compiler emitted .cfi_* directives, we could say
use .cfi_* directives for .eh_frame and hand emitted .debug_line for
.debug_frame or vice versa in the case of mixing functions with different
flags.
But inline asm can contain user written .cfi_* directives, so I think we
need to do something on the assembler side and then adjust gcc.
Jakub
