[libvirt] [PATCH 1/2] util: Turn virFirewallAddRule() into a macro

[Andrea Bolognani]

On Tue, 2017-01-03 at 13:46 +0100, Martin Kletzander wrote:
> > To solve the issue, turn virFirewallAddRule() from a very thin
> > wrapper around virFirewallAddRuleFullV() to a macro that expands
> > to a call to virFirewallAddRuleFull() - itself a very thin wrapper
> > around the aforementioned virFirewallAddRuleFullV() - with no loss
> > of functionality or type safety.
> > ---
> > This only seems to be required on very specific combinations
> > of Clang and host OS, eg. I need it on Clang 3.9 / Fedora
> > rawhide but not on Clang 3.8 or 4.0 / Debian sid.
> 
> We sent various patches for this (me, Jan and maybe other people as
> well).  I never realized it's not a problem with different versions of
> clang.

Oh, must have missed the previous attempts to fix this.

> I would say it's not a problem for us to solve it in this case,
> however, as I wrote in my solution, it works, but it's undefined from
> the specification point of view.  Can it work just because
> virFirewallAddRule() gets optimized into inline function?  it shouldn't
> be, though...  I don't know.

I lean towards merging this or a comparable solution. It's
true that we aren't currently hitting this on our main
targets, but relying on undefined behavior is definitely
something we want to avoid, plus I don't see any real
drawbacks in changing this to a macro.

-- 
Andrea Bolognani / Red Hat / Virtualization