Re: [PATCH 7/7] DWARF: add the config option

From: Josh Poimboeuf
Date: Mon May 08 2017 - 23:38:39 EST


On Mon, May 08, 2017 at 07:31:50PM -0700, Andy Lutomirski wrote:
> On Mon, May 8, 2017 at 6:38 PM, Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >> Also, don't you need some indication of which reg is the base from
> >> which you find previous frame? After all, sometimes GCC will emit a
> >> frame pointer even in an otherwise frame-pointer-omitting kernel.
> >
> > I don't think we *need* to do that. I believe the base reg can just
> > always[*] be the stack pointer, even with frame pointers.
>
> What if there are functions that use alloca or variable length arrays
> on the stack? Functions using AHASH_REQUEST_ON_STACK come to mind.

Wow, mind blown. This is why I added you to CC!

Ok, I guess we'll need to be able to use the frame pointer as a base
reg. It should be easy anyway.

--
Josh