Re: gcc: optimizations, and stack traces

[Joerg Sonnenberger <joerg%bec.de@localhost>]

On Fri, Feb 09, 2018 at 11:23:17AM +0100, Maxime Villard wrote:
> It implies that if a bug occurs _before_ these two instructions are executed,
> we have a %rbp that points to the _previous_ function, the one we got called
> from. And therefore, GDB does not display the current function (where the bug
> actually happened), but displays its caller.

This analysis is wrong. GDB will first of all look for frame annotation
data, i.e. .eh_frame or the corresponding .debug_frame. Only if it can't
find such annotation will it fall back to guessing from the function
itself. We default to building .eh_frame for all binaries, but I'm not
completely sure if GCC will create async unwind tables by default.

Joerg