1 // Copyright 2015 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_COMPILER_NODE_MARKER_H_ 6 #define V8_COMPILER_NODE_MARKER_H_ 7 8 #include "src/compiler/node.h" 9 10 namespace v8 { 11 namespace internal { 12 namespace compiler { 13 14 // Forward declarations. 15 class Graph; 16 17 18 // Base class for templatized NodeMarkers. 19 class NodeMarkerBase { 20 public: 21 NodeMarkerBase(Graph* graph, uint32_t num_states); 22 23 V8_INLINE Mark Get(const Node* node) { 24 Mark mark = node->mark(); 25 if (mark < mark_min_) { 26 return 0; 27 } 28 DCHECK_LT(mark, mark_max_); 29 return mark - mark_min_; 30 } 31 V8_INLINE void Set(Node* node, Mark mark) { 32 DCHECK_LT(mark, mark_max_ - mark_min_); 33 DCHECK_LT(node->mark(), mark_max_); 34 node->set_mark(mark + mark_min_); 35 } 36 37 private: 38 Mark const mark_min_; 39 Mark const mark_max_; 40 41 DISALLOW_COPY_AND_ASSIGN(NodeMarkerBase); 42 }; 43 44 // A NodeMarker assigns a local "state" to every node of a graph in constant 45 // memory. Only one NodeMarker per graph is valid at a given time, that is, 46 // after you create a NodeMarker you should no longer use NodeMarkers that 47 // were created earlier. Internally, the local state is stored in the Node 48 // structure. 49 // 50 // When you initialize a NodeMarker, all the local states are conceptually 51 // set to State(0) in constant time. 52 // 53 // In its current implementation, in debug mode NodeMarker will try to 54 // (efficiently) detect invalid use of an older NodeMarker. Namely, if you set a 55 // node with a NodeMarker, and then get or set that node with an older 56 // NodeMarker you will get a crash. 57 // 58 // GraphReducer uses a NodeMarker, so individual Reducers cannot use a 59 // NodeMarker. 60 template <typename State> 61 class NodeMarker : public NodeMarkerBase { 62 public: 63 V8_INLINE NodeMarker(Graph* graph, uint32_t num_states) 64 : NodeMarkerBase(graph, num_states) {} 65 66 V8_INLINE State Get(const Node* node) { 67 return static_cast<State>(NodeMarkerBase::Get(node)); 68 } 69 70 V8_INLINE void Set(Node* node, State state) { 71 NodeMarkerBase::Set(node, static_cast<Mark>(state)); 72 } 73 }; 74 75 } // namespace compiler 76 } // namespace internal 77 } // namespace v8 78 79 #endif // V8_COMPILER_NODE_MARKER_H_ 80
