On Mon, Nov 10, 2014 at 06:06:54PM +0000, Andrew Cagney wrote: > On 9 November 2014 17:12, Joerg Sonnenberger <jo...@britannica.bec.de> wrote: > >> >> o .eh_frame in kernel is not used yet, and safely removed from /netbsd > >> > > >> > Please do not. > >> > >> o Is it correct that .eh_frame is not used by anything at all at the > >> moment? > > > > gdb should in principle, haven't tried. libunwind is not hooked into ddb > > (yet). > > Can you be more specific? > > A remote debugger will call on either .debug_frame or .eh_frame when > generating a back-trace - what it uses depends on what it chooses to > look for first at each address. In fact, ignoring the potential for > bugs, you could: > - strip .eh_frame > - strip all debug info except .debug_frame > and still have good back-traces without weighing down the kernel's > text segment with .eh_frame info.
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. Joerg