138 lines · cpp
1//===-- Mips16RegisterInfo.cpp - MIPS16 Register Information --------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file contains the MIPS16 implementation of the TargetRegisterInfo class.10//11//===----------------------------------------------------------------------===//12 13#include "Mips16RegisterInfo.h"14#include "Mips16InstrInfo.h"15#include "MipsInstrInfo.h"16#include "llvm/CodeGen/MachineFrameInfo.h"17#include "llvm/CodeGen/MachineFunction.h"18#include "llvm/CodeGen/TargetFrameLowering.h"19#include "llvm/CodeGen/TargetInstrInfo.h"20#include "llvm/IR/Function.h"21#include "llvm/IR/Type.h"22#include "llvm/Support/Debug.h"23#include "llvm/Support/raw_ostream.h"24#include "llvm/Target/TargetMachine.h"25#include "llvm/Target/TargetOptions.h"26 27using namespace llvm;28 29#define DEBUG_TYPE "mips16-registerinfo"30 31Mips16RegisterInfo::Mips16RegisterInfo(const MipsSubtarget &STI)32 : MipsRegisterInfo(STI) {}33 34bool Mips16RegisterInfo::requiresRegisterScavenging35 (const MachineFunction &MF) const {36 return false;37}38bool Mips16RegisterInfo::requiresFrameIndexScavenging39 (const MachineFunction &MF) const {40 return false;41}42 43bool Mips16RegisterInfo::useFPForScavengingIndex44 (const MachineFunction &MF) const {45 return false;46}47 48bool Mips16RegisterInfo::saveScavengerRegister(49 MachineBasicBlock &MBB, MachineBasicBlock::iterator I,50 MachineBasicBlock::iterator &UseMI, const TargetRegisterClass *RC,51 Register Reg) const {52 DebugLoc DL;53 const TargetInstrInfo &TII = *MBB.getParent()->getSubtarget().getInstrInfo();54 TII.copyPhysReg(MBB, I, DL, Mips::T0, Reg, true);55 TII.copyPhysReg(MBB, UseMI, DL, Reg, Mips::T0, true);56 return true;57}58 59const TargetRegisterClass *60Mips16RegisterInfo::intRegClass(unsigned Size) const {61 assert(Size == 4);62 return &Mips::CPU16RegsRegClass;63}64 65void Mips16RegisterInfo::eliminateFI(MachineBasicBlock::iterator II,66 unsigned OpNo, int FrameIndex,67 uint64_t StackSize,68 int64_t SPOffset) const {69 MachineInstr &MI = *II;70 MachineFunction &MF = *MI.getParent()->getParent();71 MachineFrameInfo &MFI = MF.getFrameInfo();72 73 const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();74 int MinCSFI = 0;75 int MaxCSFI = -1;76 77 if (CSI.size()) {78 MinCSFI = CSI[0].getFrameIdx();79 MaxCSFI = CSI[CSI.size() - 1].getFrameIdx();80 }81 82 // The following stack frame objects are always83 // referenced relative to $sp:84 // 1. Outgoing arguments.85 // 2. Pointer to dynamically allocated stack space.86 // 3. Locations for callee-saved registers.87 // Everything else is referenced relative to whatever register88 // getFrameRegister() returns.89 Register FrameReg;90 91 if (FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI)92 FrameReg = Mips::SP;93 else {94 const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();95 if (TFI->hasFP(MF)) {96 FrameReg = Mips::S0;97 }98 else {99 if ((MI.getNumOperands()> OpNo+2) && MI.getOperand(OpNo+2).isReg())100 FrameReg = MI.getOperand(OpNo+2).getReg();101 else102 FrameReg = Mips::SP;103 }104 }105 // Calculate final offset.106 // - There is no need to change the offset if the frame object107 // is one of the108 // following: an outgoing argument, pointer to a dynamically allocated109 // stack space or a $gp restore location,110 // - If the frame object is any of the following,111 // its offset must be adjusted112 // by adding the size of the stack:113 // incoming argument, callee-saved register location or local variable.114 int64_t Offset;115 bool IsKill = false;116 Offset = SPOffset + (int64_t)StackSize;117 Offset += MI.getOperand(OpNo + 1).getImm();118 119 LLVM_DEBUG(errs() << "Offset : " << Offset << "\n"120 << "<--------->\n");121 122 if (!MI.isDebugValue() &&123 !Mips16InstrInfo::validImmediate(MI.getOpcode(), FrameReg, Offset)) {124 MachineBasicBlock &MBB = *MI.getParent();125 DebugLoc DL = II->getDebugLoc();126 unsigned NewImm;127 const Mips16InstrInfo &TII =128 *static_cast<const Mips16InstrInfo *>(MF.getSubtarget().getInstrInfo());129 FrameReg = TII.loadImmediate(FrameReg, Offset, MBB, II, DL, NewImm);130 Offset = SignExtend64<16>(NewImm);131 IsKill = true;132 }133 MI.getOperand(OpNo).ChangeToRegister(FrameReg, false, false, IsKill);134 MI.getOperand(OpNo + 1).ChangeToImmediate(Offset);135 136 137}138