139 lines · cpp
1//===- XtensaRegisterInfo.cpp - Xtensa 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 Xtensa implementation of the TargetRegisterInfo class.10//11//===----------------------------------------------------------------------===//12 13#include "XtensaRegisterInfo.h"14#include "MCTargetDesc/XtensaMCTargetDesc.h"15#include "XtensaInstrInfo.h"16#include "XtensaSubtarget.h"17#include "llvm/CodeGen/MachineFrameInfo.h"18#include "llvm/CodeGen/MachineFunction.h"19#include "llvm/CodeGen/MachineInstrBuilder.h"20#include "llvm/CodeGen/MachineRegisterInfo.h"21#include "llvm/Support/Debug.h"22#include "llvm/Support/ErrorHandling.h"23#include "llvm/Support/raw_ostream.h"24 25#define DEBUG_TYPE "xtensa-reg-info"26 27#define GET_REGINFO_TARGET_DESC28#include "XtensaGenRegisterInfo.inc"29 30using namespace llvm;31 32XtensaRegisterInfo::XtensaRegisterInfo(const XtensaSubtarget &STI)33 : XtensaGenRegisterInfo(Xtensa::A0), Subtarget(STI) {}34 35const uint16_t *36XtensaRegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {37 return Subtarget.isWindowedABI() ? CSRW8_Xtensa_SaveList38 : CSR_Xtensa_SaveList;39}40 41const uint32_t *42XtensaRegisterInfo::getCallPreservedMask(const MachineFunction &MF,43 CallingConv::ID) const {44 return Subtarget.isWindowedABI() ? CSRW8_Xtensa_RegMask : CSR_Xtensa_RegMask;45}46 47BitVector XtensaRegisterInfo::getReservedRegs(const MachineFunction &MF) const {48 BitVector Reserved(getNumRegs());49 const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();50 51 Reserved.set(Xtensa::A0);52 if (TFI->hasFP(MF)) {53 // Reserve frame pointer.54 Reserved.set(getFrameRegister(MF));55 }56 if (Subtarget.hasTHREADPTR()) {57 // Reserve frame pointer.58 Reserved.set(Xtensa::THREADPTR);59 }60 // Reserve stack pointer.61 Reserved.set(Xtensa::SP);62 return Reserved;63}64 65bool XtensaRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,66 int SPAdj, unsigned FIOperandNum,67 RegScavenger *RS) const {68 MachineInstr &MI = *II;69 MachineFunction &MF = *MI.getParent()->getParent();70 int FrameIndex = MI.getOperand(FIOperandNum).getIndex();71 uint64_t StackSize = MF.getFrameInfo().getStackSize();72 int64_t SPOffset = MF.getFrameInfo().getObjectOffset(FrameIndex);73 MachineFrameInfo &MFI = MF.getFrameInfo();74 const std::vector<CalleeSavedInfo> &CSI = MFI.getCalleeSavedInfo();75 int MinCSFI = 0;76 int MaxCSFI = -1;77 78 if (CSI.size()) {79 MinCSFI = CSI[0].getFrameIdx();80 MaxCSFI = CSI[CSI.size() - 1].getFrameIdx();81 }82 // The following stack frame objects are always referenced relative to $sp:83 // 1. Outgoing arguments.84 // 2. Pointer to dynamically allocated stack space.85 // 3. Locations for callee-saved registers.86 // 4. Locations for eh data registers.87 // Everything else is referenced relative to whatever register88 // getFrameRegister() returns.89 MCRegister FrameReg;90 if ((FrameIndex >= MinCSFI && FrameIndex <= MaxCSFI))91 FrameReg = Xtensa::SP;92 else93 FrameReg = getFrameRegister(MF);94 95 // Calculate final offset.96 // - There is no need to change the offset if the frame object is one of the97 // following: an outgoing argument, pointer to a dynamically allocated98 // stack space or a $gp restore location,99 // - If the frame object is any of the following, its offset must be adjusted100 // by adding the size of the stack:101 // incoming argument, callee-saved register location or local variable.102 bool IsKill = false;103 int64_t Offset =104 SPOffset + (int64_t)StackSize + MI.getOperand(FIOperandNum + 1).getImm();105 106 bool Valid = Xtensa::isValidAddrOffsetForOpcode(MI.getOpcode(), Offset);107 108 // If MI is not a debug value, make sure Offset fits in the 16-bit immediate109 // field.110 if (!MI.isDebugValue() && !Valid) {111 MachineBasicBlock &MBB = *MI.getParent();112 DebugLoc DL = II->getDebugLoc();113 unsigned ADD = Xtensa::ADD;114 MCRegister Reg;115 const XtensaInstrInfo &TII = *static_cast<const XtensaInstrInfo *>(116 MBB.getParent()->getSubtarget().getInstrInfo());117 118 TII.loadImmediate(MBB, II, &Reg, Offset);119 BuildMI(MBB, II, DL, TII.get(ADD), Reg)120 .addReg(FrameReg)121 .addReg(Reg, RegState::Kill);122 123 FrameReg = Reg;124 Offset = 0;125 IsKill = true;126 }127 128 MI.getOperand(FIOperandNum).ChangeToRegister(FrameReg, false, false, IsKill);129 MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);130 131 return false;132}133 134Register XtensaRegisterInfo::getFrameRegister(const MachineFunction &MF) const {135 const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();136 return TFI->hasFP(MF) ? (Subtarget.isWindowedABI() ? Xtensa::A7 : Xtensa::A15)137 : Xtensa::SP;138}139