Re: [PATCH v3 4/4] objtool: orc_gen: Move orc_entry out of instruction structure
From: peterz
Date: Thu Jul 30 2020 - 09:33:49 EST
On Thu, Jul 30, 2020 at 01:40:48PM +0100, Julien Thierry wrote:
>
>
> On 7/30/20 11:03 AM, peterz@xxxxxxxxxxxxx wrote:
> > On Thu, Jul 30, 2020 at 10:41:43AM +0100, Julien Thierry wrote:
> > > One orc_entry is associated with each instruction in the object file,
> > > but having the orc_entry contained by the instruction structure forces
> > > architectures not implementing the orc subcommands to provide a dummy
> > > definition of the orc_entry.
> I guess I forgot about the usecase of running objtool on vmlinux...
Right, and LTO builds will even do ORC at that level.
> On a kernel build for x86_64 defconfig, the difference in time seems to be
> withing the noise.
Good.
> But I agree the proposed code is not ideal and on the other we've tried
> avoiding #ifdef in the code. Ideally I'd have an empty orc_entry definition
> when SUBCMD_ORC is not implemented.
>
> Would you have a suggested approach to do that?
How ugly is having that:
struct orc_entry { };
?