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 26namespace llvm { 27 28/// AntiDepBreaker - This class works into conjunction with the 29/// post-RA scheduler to rename registers to break register 30/// anti-dependencies. 31class AntiDepBreaker { 32public: 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