1 //=- llvm/CodeGen/AntiDepBreaker.h - Anti-Dependence Breaking -*- C++ -*-=// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the AntiDepBreaker class, which implements 11 // anti-dependence breaking heuristics for post-register-allocation scheduling. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CODEGEN_ANTIDEPBREAKER_H 16 #define LLVM_CODEGEN_ANTIDEPBREAKER_H 17 18 #include "llvm/CodeGen/MachineBasicBlock.h" 19 #include "llvm/CodeGen/MachineFrameInfo.h" 20 #include "llvm/CodeGen/MachineFunction.h" 21 #include "llvm/CodeGen/MachineRegisterInfo.h" 22 #include "llvm/CodeGen/ScheduleDAG.h" 23 #include "llvm/Target/TargetRegisterInfo.h" 24 #include <vector> 25 26 namespace llvm { 27 28 /// AntiDepBreaker - This class works into conjunction with the 29 /// post-RA scheduler to rename registers to break register 30 /// anti-dependencies. 31 class AntiDepBreaker { 32 public: 33 typedef std::vector<std::pair<MachineInstr *, MachineInstr *> > 34 DbgValueVector; 35 36 virtual ~AntiDepBreaker(); 37 38 /// Start - Initialize anti-dep breaking for a new basic block. 39 virtual void StartBlock(MachineBasicBlock *BB) =0; 40 41 /// BreakAntiDependencies - Identifiy anti-dependencies within a 42 /// basic-block region and break them by renaming registers. Return 43 /// the number of anti-dependencies broken. 44 /// 45 virtual unsigned BreakAntiDependencies(const std::vector<SUnit>& SUnits, 46 MachineBasicBlock::iterator Begin, 47 MachineBasicBlock::iterator End, 48 unsigned InsertPosIndex, 49 DbgValueVector &DbgValues) = 0; 50 51 /// Observe - Update liveness information to account for the current 52 /// instruction, which will not be scheduled. 53 /// 54 virtual void Observe(MachineInstr *MI, unsigned Count, 55 unsigned InsertPosIndex) =0; 56 57 /// Finish - Finish anti-dep breaking for a basic block. 58 virtual void FinishBlock() =0; 59 60 /// UpdateDbgValue - Update DBG_VALUE if dependency breaker is updating 61 /// other machine instruction to use NewReg. 62 void UpdateDbgValue(MachineInstr *MI, unsigned OldReg, unsigned NewReg) { 63 assert (MI->isDebugValue() && "MI is not DBG_VALUE!"); 64 if (MI && MI->getOperand(0).isReg() && MI->getOperand(0).getReg() == OldReg) 65 MI->getOperand(0).setReg(NewReg); 66 } 67 }; 68 69 } 70 71 #endif 72
