35   // Represents a loop in the tree of loops, including the header nodes,
37   class Loop {
39     Loop* parent() const { return parent_; }  in parent()
40     const ZoneVector<Loop*>& children() const { return children_; }  in children()
51     explicit Loop(Zone* zone)  in Loop()  function
59     Loop* parent_;
61     ZoneVector<Loop*> children_;
68   // Return the innermost nested loop, if any, that contains {node}.
69   Loop* ContainingLoop(Node* node) {  in ContainingLoop()
75   // Check if the {loop} contains the {node}, either directly or by containing
76   // a nested loop that contains {node}.
77   bool Contains(Loop* loop, Node* node) {  in Contains()  argument
78     for (Loop* c = ContainingLoop(node); c != nullptr; c = c->parent_) {  in Contains()
79       if (c == loop) return true;  in Contains()
85   const ZoneVector<Loop*>& outer_loops() const { return outer_loops_; }  in outer_loops()
87   // Return the unique loop number for a given loop. Loop numbers start at {1}.
88   int LoopNum(Loop* loop) const {  in LoopNum()  argument
89     return 1 + static_cast<int>(loop - &all_loops_[0]);  in LoopNum()
92   // Return a range which can iterate over the header nodes of {loop}.
93   NodeRange HeaderNodes(Loop* loop) {  in HeaderNodes()  argument
94     return NodeRange(&loop_nodes_[0] + loop->header_start_,  in HeaderNodes()
95                      &loop_nodes_[0] + loop->body_start_);  in HeaderNodes()
98   // Return the header control node for a loop.
99   Node* HeaderNode(Loop* loop);
101   // Return a range which can iterate over the body nodes of {loop}.
102   NodeRange BodyNodes(Loop* loop) {  in BodyNodes()  argument
103     return NodeRange(&loop_nodes_[0] + loop->body_start_,  in BodyNodes()
104                      &loop_nodes_[0] + loop->exits_start_);  in BodyNodes()
107   // Return a range which can iterate over the body nodes of {loop}.
108   NodeRange ExitNodes(Loop* loop) {  in ExitNodes()  argument
109     return NodeRange(&loop_nodes_[0] + loop->exits_start_,  in ExitNodes()
110                      &loop_nodes_[0] + loop->exits_end_);  in ExitNodes()
113   // Return a range which can iterate over the nodes of {loop}.
114   NodeRange LoopNodes(Loop* loop) {  in LoopNodes()  argument
115     return NodeRange(&loop_nodes_[0] + loop->header_start_,  in LoopNodes()
116                      &loop_nodes_[0] + loop->exits_end_);  in LoopNodes()
119   // Return the node that represents the control, i.e. the loop node itself.
120   Node* GetLoopControl(Loop* loop) {  in GetLoopControl()  argument
121     // TODO(turbofan): make the loop control node always first?  in GetLoopControl()
122     for (Node* node : HeaderNodes(loop)) {  in GetLoopControl()
133   Loop* NewLoop() {  in NewLoop()
134     all_loops_.push_back(Loop(zone_));  in NewLoop()
135     Loop* result = &all_loops_.back();  in NewLoop()
139   void SetParent(Loop* parent, Loop* child) {  in SetParent()
150   ZoneVector<Loop*> outer_loops_;
151   ZoneVector<Loop> all_loops_;
158   // Build a loop tree for the entire graph.