1 // Copyright 2016 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_REDUNDANCY_ELIMINATION_H_ 6 #define V8_COMPILER_REDUNDANCY_ELIMINATION_H_ 7 8 #include "src/compiler/graph-reducer.h" 9 10 namespace v8 { 11 namespace internal { 12 namespace compiler { 13 14 class RedundancyElimination final : public AdvancedReducer { 15 public: 16 RedundancyElimination(Editor* editor, Zone* zone); 17 ~RedundancyElimination() final; 18 19 Reduction Reduce(Node* node) final; 20 21 private: 22 struct Check { 23 Check(Node* node, Check* next) : node(node), next(next) {} 24 Node* node; 25 Check* next; 26 }; 27 28 class EffectPathChecks final { 29 public: 30 static EffectPathChecks* Copy(Zone* zone, EffectPathChecks const* checks); 31 static EffectPathChecks const* Empty(Zone* zone); 32 void Merge(EffectPathChecks const* that); 33 34 EffectPathChecks const* AddCheck(Zone* zone, Node* node) const; 35 Node* LookupCheck(Node* node) const; 36 37 private: 38 EffectPathChecks(Check* head, size_t size) : head_(head), size_(size) {} 39 40 // We keep track of the list length so that we can find the longest 41 // common tail easily. 42 Check* head_; 43 size_t size_; 44 }; 45 46 class PathChecksForEffectNodes final { 47 public: 48 explicit PathChecksForEffectNodes(Zone* zone) : info_for_node_(zone) {} 49 EffectPathChecks const* Get(Node* node) const; 50 void Set(Node* node, EffectPathChecks const* checks); 51 52 private: 53 ZoneVector<EffectPathChecks const*> info_for_node_; 54 }; 55 56 Reduction ReduceCheckNode(Node* node); 57 Reduction ReduceEffectPhi(Node* node); 58 Reduction ReduceStart(Node* node); 59 Reduction ReduceOtherNode(Node* node); 60 61 Reduction TakeChecksFromFirstEffect(Node* node); 62 Reduction UpdateChecks(Node* node, EffectPathChecks const* checks); 63 64 Zone* zone() const { return zone_; } 65 66 PathChecksForEffectNodes node_checks_; 67 Zone* const zone_; 68 69 DISALLOW_COPY_AND_ASSIGN(RedundancyElimination); 70 }; 71 72 } // namespace compiler 73 } // namespace internal 74 } // namespace v8 75 76 #endif // V8_COMPILER_REDUNDANCY_ELIMINATION_H_ 77
