Re: [PATCH v3 4/4] objtool: orc_gen: Move orc_entry out of instruction structure

[Josh Poimboeuf]

On Thu, Jul 30, 2020 at 02:45:46PM +0100, Julien Thierry wrote:
> > > 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 { };
> > 
> > ?
> 
> Not sure I am understanding the suggestion. Without #ifdef this will
> conflict with the definition in <asm/orc_types.h> for x86. Or every arch
> needs to provide their own <asm/orc_types.h> and definition of struct
> orc_entry, even if they don't implement the orc subcommand.
> 
> Which would be preferable? #ifdef? or arch provided definition? (or
> something I have not thought of)

If we wanted to get fancy we could add a 'struct insn_arch_specific
arch' field, and then require every arch to declare it.

But I think just an #ifdef in the 'instruction' struct declaration would
be easiest for now.

-- 
Josh