1 // Copyright 2014 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_AST_LOOP_ASSIGNMENT_ANALYZER_H_ 6 #define V8_COMPILER_AST_LOOP_ASSIGNMENT_ANALYZER_H_ 7 8 #include "src/ast/ast.h" 9 #include "src/bit-vector.h" 10 #include "src/zone-containers.h" 11 12 namespace v8 { 13 namespace internal { 14 15 class Variable; 16 class Scope; 17 18 namespace compiler { 19 20 // The result of analyzing loop assignments. 21 class LoopAssignmentAnalysis : public ZoneObject { 22 public: GetVariablesAssignedInLoop(IterationStatement * loop)23 BitVector* GetVariablesAssignedInLoop(IterationStatement* loop) { 24 for (size_t i = 0; i < list_.size(); i++) { 25 // TODO(turbofan): hashmap or binary search for loop assignments. 26 if (list_[i].first == loop) return list_[i].second; 27 } 28 UNREACHABLE(); // should never ask for loops that aren't here! 29 return nullptr; 30 } 31 32 int GetAssignmentCountForTesting(Scope* scope, Variable* var); 33 34 private: 35 friend class AstLoopAssignmentAnalyzer; LoopAssignmentAnalysis(Zone * zone)36 explicit LoopAssignmentAnalysis(Zone* zone) : list_(zone) {} 37 ZoneVector<std::pair<IterationStatement*, BitVector*>> list_; 38 }; 39 40 41 // The class that performs loop assignment analysis by walking the AST. 42 class AstLoopAssignmentAnalyzer : public AstVisitor { 43 public: 44 AstLoopAssignmentAnalyzer(Zone* zone, CompilationInfo* info); 45 46 LoopAssignmentAnalysis* Analyze(); 47 48 #define DECLARE_VISIT(type) void Visit##type(type* node) override; 49 AST_NODE_LIST(DECLARE_VISIT) 50 #undef DECLARE_VISIT 51 52 static int GetVariableIndex(Scope* scope, Variable* var); 53 54 private: 55 CompilationInfo* info_; 56 Zone* zone_; 57 ZoneDeque<BitVector*> loop_stack_; 58 LoopAssignmentAnalysis* result_; 59 info()60 CompilationInfo* info() { return info_; } 61 62 void Enter(IterationStatement* loop); 63 void Exit(IterationStatement* loop); 64 VisitIfNotNull(AstNode * node)65 void VisitIfNotNull(AstNode* node) { 66 if (node != nullptr) Visit(node); 67 } 68 69 void AnalyzeAssignment(Variable* var); 70 71 DEFINE_AST_VISITOR_SUBCLASS_MEMBERS(); 72 DISALLOW_COPY_AND_ASSIGN(AstLoopAssignmentAnalyzer); 73 }; 74 } // namespace compiler 75 } // namespace internal 76 } // namespace v8 77 78 #endif // V8_COMPILER_AST_LOOP_ASSIGNMENT_ANALYZER_H_ 79