+/// unlinkNode - Unlink the specified node from this chain. If Other == this,
+/// we unlink the next pointer and return it. Otherwise we unlink Other from
+/// the list and return this.
+Matcher *Matcher::unlinkNode(Matcher *Other) {
+ if (this == Other)
+ return takeNext();
+
+ // Scan until we find the predecessor of Other.
+ Matcher *Cur = this;
+ for (; Cur && Cur->getNext() != Other; Cur = Cur->getNext())
+ /*empty*/;
+
+ if (!Cur) return nullptr;
+ Cur->takeNext();
+ Cur->setNext(Other->takeNext());
+ return this;
+}
+
+/// canMoveBefore - Return true if this matcher is the same as Other, or if
+/// we can move this matcher past all of the nodes in-between Other and this
+/// node. Other must be equal to or before this.
+bool Matcher::canMoveBefore(const Matcher *Other) const {
+ for (;; Other = Other->getNext()) {
+ assert(Other && "Other didn't come before 'this'?");
+ if (this == Other) return true;
+
+ // We have to be able to move this node across the Other node.
+ if (!canMoveBeforeNode(Other))
+ return false;
+ }
+}
+
+/// canMoveBeforeNode - Return true if it is safe to move the current matcher
+/// across the specified one.
+bool Matcher::canMoveBeforeNode(const Matcher *Other) const {
+ // We can move simple predicates before record nodes.
+ if (isSimplePredicateNode())
+ return Other->isSimplePredicateOrRecordNode();
+
+ // We can move record nodes across simple predicates.
+ if (isSimplePredicateOrRecordNode())
+ return isSimplePredicateNode();
+
+ // We can't move record nodes across each other etc.
+ return false;
+}
+
+