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|
// RUN: %boogie -noinfer -typeEncoding:m -useArrayTheory %s > %t
// RUN: %diff %s.expect %t
type X;
const nil: X;
function {:builtin "MapConst"} MapConstBool(bool) : [X]bool;
function {:inline} {:linear "tid"} TidCollector(x: X) : [X]bool
{
MapConstBool(false)[x := true]
}
type lmap;
function {:linear "mem"} dom(lmap): [int]bool;
function map(lmap): [int]int;
function cons([int]bool, [int]int) : lmap;
axiom (forall x: [int]bool, y: [int]int :: {cons(x,y)} dom(cons(x, y)) == x && map(cons(x,y)) == y);
var {:phase 2} {:linear "mem"} g: lmap;
const p: int;
procedure {:yields} {:phase 1,2} TransferToGlobal({:cnst "tid"} tid: X, {:linear "mem"} l: lmap);
ensures {:both} |{ A: assert tid != nil && lock == tid; g := l; return true; }|;
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
procedure {:yields} {:phase 1,2} TransferFromGlobal({:cnst "tid"} tid: X) returns ({:linear "mem"} l: lmap);
ensures {:both} |{ A: assert tid != nil && lock == tid; l := g; return true; }|;
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
procedure {:yields} {:phase 1} Load({:cnst "mem"} l: lmap, a: int) returns (v: int);
ensures {:both} |{ A: v := map(l)[a]; return true; }|;
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
procedure {:yields} {:phase 1} Store({:linear "mem"} l_in: lmap, a: int, v: int) returns ({:linear "mem"} l_out: lmap);
ensures {:both} |{ A: assume l_out == cons(dom(l_in), map(l_in)[a := v]); return true; }|;
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
procedure {:yields} {:phase 2} P({:cnst "tid"} tid: X)
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
requires {:phase 2} tid != nil && Inv(g);
ensures {:phase 2} Inv(g);
{
var t: int;
var {:linear "mem"} l: lmap;
par Yield() | YieldLock();
call Acquire(tid);
call l := TransferFromGlobal(tid);
call t := Load(l, p);
call l := Store(l, p, t+1);
call t := Load(l, p+4);
call l := Store(l, p+4, t+1);
call TransferToGlobal(tid, l);
call Release(tid);
par Yield() | YieldLock();
}
procedure {:yields} {:phase 2} Yield()
requires {:phase 2} Inv(g);
ensures {:phase 2} Inv(g);
{
yield;
assert {:phase 2} Inv(g);
}
function {:inline} Inv(g: lmap) : bool
{
dom(g)[p] && dom(g)[p+4] && map(g)[p] == map(g)[p+4]
}
var {:phase 1} b: bool;
var {:phase 2} lock: X;
procedure {:yields} {:phase 1,2} Acquire({:cnst "tid"} tid: X)
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
ensures {:right} |{ A: assert tid != nil; assume lock == nil; lock := tid; return true; }|;
{
var status: bool;
var tmp: X;
par YieldLock();
L:
assert {:phase 1} InvLock(lock, b);
call status := CAS(tid, false, true);
par YieldLock();
goto A, B;
A:
assume status;
par YieldLock();
return;
B:
assume !status;
goto L;
}
procedure {:yields} {:phase 1,2} Release({:cnst "tid"} tid: X)
ensures {:left} |{ A: assert lock == tid && tid != nil; lock := nil; return true; }|;
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
{
par YieldLock();
call CLEAR(tid, false);
par YieldLock();
}
procedure {:yields} {:phase 0,1} CAS(tid: X, prev: bool, next: bool) returns (status: bool);
ensures {:atomic} |{
A: goto B, C;
B: assume b == prev; b := next; status := true; lock := tid; return true;
C: status := false; return true;
}|;
procedure {:yields} {:phase 0,1} CLEAR(tid: X, next: bool);
ensures {:atomic} |{
A: b := next; lock := nil; return true;
}|;
procedure {:yields} {:phase 1} YieldLock()
requires {:phase 1} InvLock(lock, b);
ensures {:phase 1} InvLock(lock, b);
{
yield;
assert {:phase 1} InvLock(lock, b);
}
function {:inline} InvLock(lock: X, b: bool) : bool
{
lock != nil <==> b
}
|
