Re: [PATCH 1/7] rust: file: add Rust abstraction for `struct file`

[Boqun Feng]

On Fri, Dec 01, 2023 at 10:00:39AM +0100, Peter Zijlstra wrote:
> On Thu, Nov 30, 2023 at 07:25:01AM -0800, Boqun Feng wrote:
> 
> > seems to me, the plan for this is something like below:
> > 
> > 	asm!(
> > 		"cmp {}, 42",
> > 		"jeq {}",
> > 		in(reg) val,
> > 		label { println!("a"); },
> > 		fallthrough { println!("b"); }
> >     	);
> 
> Because rust has horrible syntax I can't parse, I can't tell if this is
> useful or not :/ Can this be used to implement arch_static_branch*() ?

I should think so:

	asm!("jmp {l_yes}", // jump to l_yes
	     "..."          // directives are supported
	     l_yes { return true; } // label "l_yes"
	     fallthrough { return false; } // otherwise return false
	)

Rust uses LLVM backend, so the inline asm should have the same ability
of clang.

But as I said, AFAIK jumping to label hasn't been implemented yet.

Regards,
Boqun