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(Node* node) { 24 Mark mark = node->mark(); 25 if (mark < mark_min_) { 26 mark = mark_min_; 27 node->set_mark(mark_min_); 28 } 29 DCHECK_LT(mark, mark_max_); 30 return mark - mark_min_; 31 } 32 V8_INLINE void Set(Node* node, Mark mark) { 33 DCHECK_LT(mark, mark_max_ - mark_min_); 34 DCHECK_LT(node->mark(), mark_max_); 35 node->set_mark(mark + mark_min_); 36 } 37 38 private: 39 Mark const mark_min_; 40 Mark const mark_max_; 41 42 DISALLOW_COPY_AND_ASSIGN(NodeMarkerBase); 43 }; 44 45 // A NodeMarker assigns a local "state" to every node of a graph in constant 46 // memory. Only one NodeMarker per graph is valid at a given time, that is, 47 // after you create a NodeMarker you should no longer use NodeMarkers that 48 // were created earlier. Internally, the local state is stored in the Node 49 // structure. 50 // 51 // When you initialize a NodeMarker, all the local states are conceptually 52 // set to State(0) in constant time. 53 // 54 // In its current implementation, in debug mode NodeMarker will try to 55 // (efficiently) detect invalid use of an older NodeMarker. Namely, if you get 56 // or set a node with a NodeMarker, and then get or set that node 57 // with an older NodeMarker you will get a crash. 58 // 59 // GraphReducer uses a NodeMarker, so individual Reducers cannot use a 60 // NodeMarker. 61 template <typename State> 62 class NodeMarker : public NodeMarkerBase { 63 public: 64 V8_INLINE NodeMarker(Graph* graph, uint32_t num_states) 65 : NodeMarkerBase(graph, num_states) {} 66 67 V8_INLINE State Get(Node* node) { 68 return static_cast<State>(NodeMarkerBase::Get(node)); 69 } 70 71 V8_INLINE void Set(Node* node, State state) { 72 NodeMarkerBase::Set(node, static_cast<Mark>(state)); 73 } 74 }; 75 76 } // namespace compiler 77 } // namespace internal 78 } // namespace v8 79 80 #endif // V8_COMPILER_NODE_MARKER_H_ 81
