tools/memory-model: Improve mixed-access checking in lock.cat

 * LKW, LF, RL, and RU have no ordering properties.

 *)

(* Backward compatibility *)

let RL = try RL with emptyset

let RU = try RU with emptyset

(* Treat RL as a kind of LF: a read with no ordering properties *)

let LF = LF | RL

(* There should be no ordinary R or W accesses to spinlocks *)

let ALL-LOCKS = LKR | LKW | UL | LF | RU

flag ~empty [M \ IW] ; loc ; [ALL-LOCKS] as mixed-lock-accesses

(* Link Lock-Reads to their RMW-partner Lock-Writes *)

let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po)

let rmw = rmw | lk-rmw

(* This will be allowed if we implement spin_is_locked() *)

flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR

(* There should be no ordinary R or W accesses to spinlocks *)

let ALL-LOCKS = LKR | LKW | UL | LF

flag ~empty [M \ IW] ; loc ; [ALL-LOCKS] as mixed-lock-accesses

(* The final value of a spinlock should not be tested *)

flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final

(* Backward compatibility *)

let RL = try RL with emptyset

let RU = try RU with emptyset

(* Treat RL as a kind of LF: a read with no ordering properties *)

let LF = LF | RL

(*

 * Put lock operations in their appropriate classes, but leave UL out of W

 * until after the co relation has been generated.