| // Copyright 2013 the V8 project authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef V8_COMPILER_GENERIC_ALGORITHM_H_ |
| #define V8_COMPILER_GENERIC_ALGORITHM_H_ |
| |
| #include <stack> |
| |
| #include "src/compiler/generic-graph.h" |
| #include "src/compiler/generic-node.h" |
| #include "src/zone-containers.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace compiler { |
| |
| // GenericGraphVisit allows visitation of graphs of nodes and edges in pre- and |
| // post-order. Visitation uses an explicitly allocated stack rather than the |
| // execution stack to avoid stack overflow. Although GenericGraphVisit is |
| // primarily intended to traverse networks of nodes through their |
| // dependencies and uses, it also can be used to visit any graph-like network |
| // by specifying custom traits. |
| class GenericGraphVisit { |
| public: |
| // struct Visitor { |
| // void Pre(Traits::Node* current); |
| // void Post(Traits::Node* current); |
| // void PreEdge(Traits::Node* from, int index, Traits::Node* to); |
| // void PostEdge(Traits::Node* from, int index, Traits::Node* to); |
| // } |
| template <class Visitor, class Traits, class RootIterator> |
| static void Visit(GenericGraphBase* graph, Zone* zone, |
| RootIterator root_begin, RootIterator root_end, |
| Visitor* visitor) { |
| typedef typename Traits::Node Node; |
| typedef typename Traits::Iterator Iterator; |
| typedef std::pair<Iterator, Iterator> NodeState; |
| typedef std::stack<NodeState, ZoneDeque<NodeState> > NodeStateStack; |
| NodeStateStack stack((ZoneDeque<NodeState>(zone))); |
| BoolVector visited(Traits::max_id(graph), false, zone); |
| Node* current = *root_begin; |
| while (true) { |
| DCHECK(current != NULL); |
| const int id = current->id(); |
| DCHECK(id >= 0); |
| DCHECK(id < Traits::max_id(graph)); // Must be a valid id. |
| bool visit = !GetVisited(&visited, id); |
| if (visit) { |
| visitor->Pre(current); |
| SetVisited(&visited, id); |
| } |
| Iterator begin(visit ? Traits::begin(current) : Traits::end(current)); |
| Iterator end(Traits::end(current)); |
| stack.push(NodeState(begin, end)); |
| Node* post_order_node = current; |
| while (true) { |
| NodeState top = stack.top(); |
| if (top.first == top.second) { |
| if (visit) { |
| visitor->Post(post_order_node); |
| SetVisited(&visited, post_order_node->id()); |
| } |
| stack.pop(); |
| if (stack.empty()) { |
| if (++root_begin == root_end) return; |
| current = *root_begin; |
| break; |
| } |
| post_order_node = Traits::from(stack.top().first); |
| visit = true; |
| } else { |
| visitor->PreEdge(Traits::from(top.first), top.first.edge().index(), |
| Traits::to(top.first)); |
| current = Traits::to(top.first); |
| if (!GetVisited(&visited, current->id())) break; |
| } |
| top = stack.top(); |
| visitor->PostEdge(Traits::from(top.first), top.first.edge().index(), |
| Traits::to(top.first)); |
| ++stack.top().first; |
| } |
| } |
| } |
| |
| template <class Visitor, class Traits> |
| static void Visit(GenericGraphBase* graph, Zone* zone, |
| typename Traits::Node* current, Visitor* visitor) { |
| typename Traits::Node* array[] = {current}; |
| Visit<Visitor, Traits>(graph, zone, &array[0], &array[1], visitor); |
| } |
| |
| template <class B, class S> |
| struct NullNodeVisitor { |
| void Pre(GenericNode<B, S>* node) {} |
| void Post(GenericNode<B, S>* node) {} |
| void PreEdge(GenericNode<B, S>* from, int index, GenericNode<B, S>* to) {} |
| void PostEdge(GenericNode<B, S>* from, int index, GenericNode<B, S>* to) {} |
| }; |
| |
| private: |
| static void SetVisited(BoolVector* visited, int id) { |
| if (id >= static_cast<int>(visited->size())) { |
| // Resize and set all values to unvisited. |
| visited->resize((3 * id) / 2, false); |
| } |
| visited->at(id) = true; |
| } |
| |
| static bool GetVisited(BoolVector* visited, int id) { |
| if (id >= static_cast<int>(visited->size())) return false; |
| return visited->at(id); |
| } |
| }; |
| } |
| } |
| } // namespace v8::internal::compiler |
| |
| #endif // V8_COMPILER_GENERIC_ALGORITHM_H_ |