1 // Copyright 2011 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_ARM_LITHIUM_GAP_RESOLVER_ARM_H_ 6 #define V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_ 7 8 #include "src/v8.h" 9 10 #include "src/lithium.h" 11 12 namespace v8 { 13 namespace internal { 14 15 class LCodeGen; 16 class LGapResolver; 17 18 class LGapResolver FINAL BASE_EMBEDDED { 19 public: 20 explicit LGapResolver(LCodeGen* owner); 21 22 // Resolve a set of parallel moves, emitting assembler instructions. 23 void Resolve(LParallelMove* parallel_move); 24 25 private: 26 // Build the initial list of moves. 27 void BuildInitialMoveList(LParallelMove* parallel_move); 28 29 // Perform the move at the moves_ index in question (possibly requiring 30 // other moves to satisfy dependencies). 31 void PerformMove(int index); 32 33 // If a cycle is found in the series of moves, save the blocking value to 34 // a scratch register. The cycle must be found by hitting the root of the 35 // depth-first search. 36 void BreakCycle(int index); 37 38 // After a cycle has been resolved, restore the value from the scratch 39 // register to its proper destination. 40 void RestoreValue(); 41 42 // Emit a move and remove it from the move graph. 43 void EmitMove(int index); 44 45 // Verify the move list before performing moves. 46 void Verify(); 47 48 LCodeGen* cgen_; 49 50 // List of moves not yet resolved. 51 ZoneList<LMoveOperands> moves_; 52 53 int root_index_; 54 bool in_cycle_; 55 LOperand* saved_destination_; 56 57 // We use the root register as a scratch in a few places. When that happens, 58 // this flag is set to indicate that it needs to be restored. 59 bool need_to_restore_root_; 60 }; 61 62 } } // namespace v8::internal 63 64 #endif // V8_ARM_LITHIUM_GAP_RESOLVER_ARM_H_ 65