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DGLM.cola
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DGLM.cola
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#name "DGLM Queue EBR"
#smr "EBR"
#cavespec "../queue_spec.cav"
#cavelin 'prover_opts imp_var = "CC_.Tail.next";'
#instrumentation "container"
struct Node {
data_t val;
Node* next;
}
Node* Tail;
Node* Head;
extern void retire(Node* ptr);
extern void enterQ();
extern void leaveQ();
void init() {
Head = malloc;
Head->next = NULL;
Tail = Head;
}
void enqueue(data_t value) {
Node* tail, next, node;
node = malloc;
node->val = value;
node->next = NULL;
atomic {
angel(choose active);
leaveQ();
}
while (true) {
tail = Tail;
angel(member(tail));
next = tail->next;
angel(member(next));
if (tail == Tail) {
if (next != NULL) {
CAS(Tail, tail, next);
} else {
if (CAS(tail->next, NULL, node)) {
CAS(Tail, tail, node);
break;
}
}
}
}
enterQ();
}
data_t dequeue() {
Node* head, next, tail;
data_t result;
bool flag;
atomic {
angel(choose active);
leaveQ();
}
while (true) {
head = Head;
angel(member(head));
next = head->next;
angel(member(next));
if (head == Head) {
if (next == NULL) {
result = EMPTY;
break;
} else {
result = next->val;
atomic {
if (CAS(Head, head, next)) {
flag = true;
} else {
flag = false;
}
}
if (flag) {
choose {
tail = Tail;
angel(member(tail));
assume(head == tail);
CAS(Tail, tail, next);
}{
tail = Tail;
assume(head != tail);
}
atomic {
assert(active(head));
retire(head);
}
break;
}
}
}
}
enterQ();
return result;
}