Re: .eh_frame

[Andrew Cagney <andrew.cagney%gmail.com@localhost>]

On 10 November 2014 18:21, Joerg Sonnenberger <joerg%britannica.bec.de@localhost> wrote:
> Consider x86_64 where you can't do reliable stack unwinding without also
> disabling -fomit-frame-pointer. The question is not about .debug_frame
> vs .eh_frame, you don't get the former at all without explicitly asking
> for debug data.

You've lost me.  I agree that without the help of CFI (call frame
information), amd64's stack is impenetrable goop.  That just means
that we need to ensure that there is cfi information on hand should
someone need it - in the .debug_frame section instead of .eh_frame.

(small technical nit, currently to get just the .debug_frame section,
gcc seems to require: -fno-unwind-tables
-fno-asynchronous-unwind-tables -g; which seems a tad excessive given
that gas's .cfi_sections pretty much does all we need)

As an aside, even with no CFI, it's still possible to get a feel for
what went down - just scan the stack for what look like code
addresses.