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// RUN: %boogie -noinfer -typeEncoding:m -useArrayTheory "%s" > "%t"
// RUN: %diff "%s.expect" "%t"
// XFAIL: *
type X;
function {:builtin "MapConst"} MapConstBool(bool) : [X]bool;
function {:inline} {:linear "tid"} TidCollector(x: X) : [X]bool
{
MapConstBool(false)[x := true]
}
function {:inline} Inv(ghostLock: X, currsize: int, newsize: int) : (bool)
{
currsize <= newsize && (ghostLock == nil <==> currsize == newsize)
}
procedure {:yields} YieldToReadCache({:linear "tid"} tid': X) returns ({:linear "tid"} tid: X)
requires tid' != nil;
requires Inv(ghostLock, currsize, newsize);
ensures Inv(ghostLock, currsize, newsize);
ensures old(currsize) <= currsize;
ensures tid == tid';
{
tid := tid';
yield;
assert Inv(ghostLock, currsize, newsize);
assert old(currsize) <= currsize;
assert tid != nil;
}
procedure {:yields} YieldToUpdateCache({:linear "tid"} tid': X, i: int) returns ({:linear "tid"} tid: X)
requires tid' != nil;
requires Inv(ghostLock, currsize, newsize);
requires ghostLock == tid';
requires currsize <= i;
ensures Inv(ghostLock, currsize, newsize);
ensures old(currsize) <= currsize;
ensures tid == tid';
ensures ghostLock == tid;
ensures currsize <= i;
ensures newsize == old(newsize);
{
tid := tid';
yield;
assert Inv(ghostLock, currsize, newsize);
assert old(currsize) <= currsize;
assert tid != nil;
assert ghostLock == tid;
assert currsize <= i;
assert newsize == old(newsize);
}
var ghostLock: X;
var lock: X;
const nil: X;
var currsize: int;
var newsize: int;
procedure acquire(tid: X);
modifies lock;
ensures old(lock) == nil && lock == tid;
procedure release(tid: X);
modifies lock;
requires lock == tid;
ensures lock == nil;
procedure {:yields} Read ({:linear "tid"} tid': X, start : int, size : int) returns (bytesread : int)
requires tid' != nil;
requires 0 <= start && 0 <= size;
requires Inv(ghostLock, currsize, newsize);
ensures 0 <= bytesread && bytesread <= size;
{
var copy_currsize: int;
var i, j, tmp : int;
var {:linear "tid"} tid: X;
tid := tid';
bytesread := size;
call acquire(tid);
i := currsize;
if (start + size <= i) {
call release(tid);
call tid := YieldToReadCache(tid);
goto COPY_TO_BUFFER;
} else if (newsize > i) {
bytesread := if (start <= i) then (i - start) else 0;
call release(tid);
call tid := YieldToReadCache(tid);
goto COPY_TO_BUFFER;
} else {
newsize := start + size;
ghostLock := tid;
call release(tid);
call tid := YieldToUpdateCache(tid, i);
goto READ_DEVICE;
}
READ_DEVICE:
while (i < start + size)
invariant Inv(ghostLock, currsize, newsize);
invariant ghostLock == tid;
invariant tid != nil;
invariant currsize <= i;
invariant newsize == start + size;
{
call tid := YieldToUpdateCache(tid, i);
assert currsize <= i;
i := i + 1;
}
call acquire(tid);
tmp := newsize;
currsize := tmp;
ghostLock := nil;
call release(tid);
call tid := YieldToReadCache(tid);
COPY_TO_BUFFER:
j := 0;
while(j < bytesread)
invariant 0 <= j;
invariant Inv(ghostLock, currsize, newsize);
invariant tid != nil;
invariant bytesread == 0 || start + bytesread <= currsize;
{
call tid := YieldToReadCache(tid);
assert start + j < currsize;
j := j + 1;
}
}
procedure {:yields} {:stable} thread({:linear "tid"} tid': X)
requires tid' != nil;
requires Inv(ghostLock, currsize, newsize);
{
var start, size, bytesread: int;
var {:linear "tid"} tid: X;
tid := tid';
havoc start, size;
assume (0 <= start && 0 <= size);
call bytesread := Read(tid, start, size);
}
procedure {:entrypoint} {:yields} main()
requires currsize == 0 && newsize == 0 && ghostLock == nil && lock == nil;
{
var {:linear "tid"} tid: X;
while (*)
{
call tid := Allocate();
async call thread(tid);
}
}
procedure Allocate() returns ({:linear "tid"} xls: X);
ensures xls != nil;
|
