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 reducer_name()19 const char* reducer_name() const override { return "RedundancyElimination"; } 20 21 Reduction Reduce(Node* node) final; 22 23 private: 24 struct Check { CheckCheck25 Check(Node* node, Check* next) : node(node), next(next) {} 26 Node* node; 27 Check* next; 28 }; 29 30 class EffectPathChecks final { 31 public: 32 static EffectPathChecks* Copy(Zone* zone, EffectPathChecks const* checks); 33 static EffectPathChecks const* Empty(Zone* zone); 34 bool Equals(EffectPathChecks const* that) const; 35 void Merge(EffectPathChecks const* that); 36 37 EffectPathChecks const* AddCheck(Zone* zone, Node* node) const; 38 Node* LookupCheck(Node* node) const; 39 Node* LookupBoundsCheckFor(Node* node) const; 40 41 private: EffectPathChecks(Check * head,size_t size)42 EffectPathChecks(Check* head, size_t size) : head_(head), size_(size) {} 43 44 // We keep track of the list length so that we can find the longest 45 // common tail easily. 46 Check* head_; 47 size_t size_; 48 }; 49 50 class PathChecksForEffectNodes final { 51 public: PathChecksForEffectNodes(Zone * zone)52 explicit PathChecksForEffectNodes(Zone* zone) : info_for_node_(zone) {} 53 EffectPathChecks const* Get(Node* node) const; 54 void Set(Node* node, EffectPathChecks const* checks); 55 56 private: 57 ZoneVector<EffectPathChecks const*> info_for_node_; 58 }; 59 60 Reduction ReduceCheckNode(Node* node); 61 Reduction ReduceEffectPhi(Node* node); 62 Reduction ReduceStart(Node* node); 63 Reduction ReduceOtherNode(Node* node); 64 65 Reduction TakeChecksFromFirstEffect(Node* node); 66 Reduction UpdateChecks(Node* node, EffectPathChecks const* checks); 67 68 Reduction TryReuseBoundsCheckForFirstInput(Node* node); 69 zone()70 Zone* zone() const { return zone_; } 71 72 PathChecksForEffectNodes node_checks_; 73 Zone* const zone_; 74 75 DISALLOW_COPY_AND_ASSIGN(RedundancyElimination); 76 }; 77 78 } // namespace compiler 79 } // namespace internal 80 } // namespace v8 81 82 #endif // V8_COMPILER_REDUNDANCY_ELIMINATION_H_ 83