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_BYTECODE_LOOP_ANALYSIS_H_ 6 #define V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_ 7 8 #include "src/handles.h" 9 #include "src/zone/zone-containers.h" 10 11 namespace v8 { 12 namespace internal { 13 14 class BytecodeArray; 15 16 namespace compiler { 17 18 class BytecodeBranchAnalysis; 19 20 class BytecodeLoopAnalysis BASE_EMBEDDED { 21 public: 22 BytecodeLoopAnalysis(Handle<BytecodeArray> bytecode_array, 23 const BytecodeBranchAnalysis* branch_analysis, 24 Zone* zone); 25 26 // Analyze the bytecodes to find the branch sites and their 27 // targets. No other methods in this class return valid information 28 // until this has been called. 29 void Analyze(); 30 31 // Get the loop header offset of the containing loop for arbitrary 32 // {offset}, or -1 if the {offset} is not inside any loop. 33 int GetLoopOffsetFor(int offset) const; 34 // Gets the loop header offset of the parent loop of the loop header 35 // at {header_offset}, or -1 for outer-most loops. 36 int GetParentLoopFor(int header_offset) const; 37 38 private: 39 void AddLoopEntry(int entry_offset); 40 void AddBranch(int origin_offset, int target_offset); 41 zone()42 Zone* zone() const { return zone_; } bytecode_array()43 Handle<BytecodeArray> bytecode_array() const { return bytecode_array_; } 44 45 Handle<BytecodeArray> bytecode_array_; 46 const BytecodeBranchAnalysis* branch_analysis_; 47 Zone* zone_; 48 49 int current_loop_offset_; 50 bool found_current_backedge_; 51 52 // Map from the offset of a backedge jump to the offset of the corresponding 53 // loop header. There might be multiple backedges for do-while loops. 54 ZoneMap<int, int> backedge_to_header_; 55 // Map from the offset of a loop header to the offset of its parent's loop 56 // header. This map will have as many entries as there are loops in the 57 // function. 58 ZoneMap<int, int> loop_header_to_parent_; 59 60 DISALLOW_COPY_AND_ASSIGN(BytecodeLoopAnalysis); 61 }; 62 63 } // namespace compiler 64 } // namespace internal 65 } // namespace v8 66 67 #endif // V8_COMPILER_BYTECODE_LOOP_ANALYSIS_H_ 68