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llvm-mirror/lib/Target/Lanai/LanaiRegisterInfo.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

271 lines
8.6 KiB
C++

//===-- LanaiRegisterInfo.cpp - Lanai Register Information ------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the Lanai implementation of the TargetRegisterInfo class.
//
//===----------------------------------------------------------------------===//
#include "LanaiRegisterInfo.h"
#include "Lanai.h"
#include "LanaiSubtarget.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/RegisterScavenging.h"
#include "llvm/CodeGen/TargetFrameLowering.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/ErrorHandling.h"
#define GET_REGINFO_TARGET_DESC
#include "LanaiGenRegisterInfo.inc"
using namespace llvm;
LanaiRegisterInfo::LanaiRegisterInfo() : LanaiGenRegisterInfo(Lanai::RCA) {}
const uint16_t *
LanaiRegisterInfo::getCalleeSavedRegs(const MachineFunction * /*MF*/) const {
return CSR_SaveList;
}
BitVector LanaiRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
BitVector Reserved(getNumRegs());
Reserved.set(Lanai::R0);
Reserved.set(Lanai::R1);
Reserved.set(Lanai::PC);
Reserved.set(Lanai::R2);
Reserved.set(Lanai::SP);
Reserved.set(Lanai::R4);
Reserved.set(Lanai::FP);
Reserved.set(Lanai::R5);
Reserved.set(Lanai::RR1);
Reserved.set(Lanai::R10);
Reserved.set(Lanai::RR2);
Reserved.set(Lanai::R11);
Reserved.set(Lanai::RCA);
Reserved.set(Lanai::R15);
if (hasBasePointer(MF))
Reserved.set(getBaseRegister());
return Reserved;
}
bool LanaiRegisterInfo::requiresRegisterScavenging(
const MachineFunction & /*MF*/) const {
return true;
}
bool LanaiRegisterInfo::trackLivenessAfterRegAlloc(
const MachineFunction & /*MF*/) const {
return true;
}
static bool isALUArithLoOpcode(unsigned Opcode) {
switch (Opcode) {
case Lanai::ADD_I_LO:
case Lanai::SUB_I_LO:
case Lanai::ADD_F_I_LO:
case Lanai::SUB_F_I_LO:
case Lanai::ADDC_I_LO:
case Lanai::SUBB_I_LO:
case Lanai::ADDC_F_I_LO:
case Lanai::SUBB_F_I_LO:
return true;
default:
return false;
}
}
static unsigned getOppositeALULoOpcode(unsigned Opcode) {
switch (Opcode) {
case Lanai::ADD_I_LO:
return Lanai::SUB_I_LO;
case Lanai::SUB_I_LO:
return Lanai::ADD_I_LO;
case Lanai::ADD_F_I_LO:
return Lanai::SUB_F_I_LO;
case Lanai::SUB_F_I_LO:
return Lanai::ADD_F_I_LO;
case Lanai::ADDC_I_LO:
return Lanai::SUBB_I_LO;
case Lanai::SUBB_I_LO:
return Lanai::ADDC_I_LO;
case Lanai::ADDC_F_I_LO:
return Lanai::SUBB_F_I_LO;
case Lanai::SUBB_F_I_LO:
return Lanai::ADDC_F_I_LO;
default:
llvm_unreachable("Invalid ALU lo opcode");
}
}
static unsigned getRRMOpcodeVariant(unsigned Opcode) {
switch (Opcode) {
case Lanai::LDBs_RI:
return Lanai::LDBs_RR;
case Lanai::LDBz_RI:
return Lanai::LDBz_RR;
case Lanai::LDHs_RI:
return Lanai::LDHs_RR;
case Lanai::LDHz_RI:
return Lanai::LDHz_RR;
case Lanai::LDW_RI:
return Lanai::LDW_RR;
case Lanai::STB_RI:
return Lanai::STB_RR;
case Lanai::STH_RI:
return Lanai::STH_RR;
case Lanai::SW_RI:
return Lanai::SW_RR;
default:
llvm_unreachable("Opcode has no RRM variant");
}
}
void LanaiRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
int SPAdj, unsigned FIOperandNum,
RegScavenger *RS) const {
assert(SPAdj == 0 && "Unexpected");
MachineInstr &MI = *II;
MachineFunction &MF = *MI.getParent()->getParent();
const TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
const TargetFrameLowering *TFI = MF.getSubtarget().getFrameLowering();
bool HasFP = TFI->hasFP(MF);
DebugLoc DL = MI.getDebugLoc();
int FrameIndex = MI.getOperand(FIOperandNum).getIndex();
int Offset = MF.getFrameInfo().getObjectOffset(FrameIndex) +
MI.getOperand(FIOperandNum + 1).getImm();
// Addressable stack objects are addressed using neg. offsets from fp
// or pos. offsets from sp/basepointer
if (!HasFP || (needsStackRealignment(MF) && FrameIndex >= 0))
Offset += MF.getFrameInfo().getStackSize();
unsigned FrameReg = getFrameRegister(MF);
if (FrameIndex >= 0) {
if (hasBasePointer(MF))
FrameReg = getBaseRegister();
else if (needsStackRealignment(MF))
FrameReg = Lanai::SP;
}
// Replace frame index with a frame pointer reference.
// If the offset is small enough to fit in the immediate field, directly
// encode it.
// Otherwise scavenge a register and encode it into a MOVHI, OR_I_LO sequence.
if ((isSPLSOpcode(MI.getOpcode()) && !isInt<10>(Offset)) ||
!isInt<16>(Offset)) {
assert(RS && "Register scavenging must be on");
unsigned Reg = RS->FindUnusedReg(&Lanai::GPRRegClass);
if (!Reg)
Reg = RS->scavengeRegister(&Lanai::GPRRegClass, II, SPAdj);
assert(Reg && "Register scavenger failed");
bool HasNegOffset = false;
// ALU ops have unsigned immediate values. If the Offset is negative, we
// negate it here and reverse the opcode later.
if (Offset < 0) {
HasNegOffset = true;
Offset = -Offset;
}
if (!isInt<16>(Offset)) {
// Reg = hi(offset) | lo(offset)
BuildMI(*MI.getParent(), II, DL, TII->get(Lanai::MOVHI), Reg)
.addImm(static_cast<uint32_t>(Offset) >> 16);
BuildMI(*MI.getParent(), II, DL, TII->get(Lanai::OR_I_LO), Reg)
.addReg(Reg)
.addImm(Offset & 0xffffU);
} else {
// Reg = mov(offset)
BuildMI(*MI.getParent(), II, DL, TII->get(Lanai::ADD_I_LO), Reg)
.addImm(0)
.addImm(Offset);
}
// Reg = FrameReg OP Reg
if (MI.getOpcode() == Lanai::ADD_I_LO) {
BuildMI(*MI.getParent(), II, DL,
HasNegOffset ? TII->get(Lanai::SUB_R) : TII->get(Lanai::ADD_R),
MI.getOperand(0).getReg())
.addReg(FrameReg)
.addReg(Reg)
.addImm(LPCC::ICC_T);
MI.eraseFromParent();
return;
}
if (isSPLSOpcode(MI.getOpcode()) || isRMOpcode(MI.getOpcode())) {
MI.setDesc(TII->get(getRRMOpcodeVariant(MI.getOpcode())));
if (HasNegOffset) {
// Change the ALU op (operand 3) from LPAC::ADD (the default) to
// LPAC::SUB with the already negated offset.
assert((MI.getOperand(3).getImm() == LPAC::ADD) &&
"Unexpected ALU op in RRM instruction");
MI.getOperand(3).setImm(LPAC::SUB);
}
} else
llvm_unreachable("Unexpected opcode in frame index operation");
MI.getOperand(FIOperandNum).ChangeToRegister(FrameReg, /*isDef=*/false);
MI.getOperand(FIOperandNum + 1)
.ChangeToRegister(Reg, /*isDef=*/false, /*isImp=*/false,
/*isKill=*/true);
return;
}
// ALU arithmetic ops take unsigned immediates. If the offset is negative,
// we replace the instruction with one that inverts the opcode and negates
// the immediate.
if ((Offset < 0) && isALUArithLoOpcode(MI.getOpcode())) {
unsigned NewOpcode = getOppositeALULoOpcode(MI.getOpcode());
// We know this is an ALU op, so we know the operands are as follows:
// 0: destination register
// 1: source register (frame register)
// 2: immediate
BuildMI(*MI.getParent(), II, DL, TII->get(NewOpcode),
MI.getOperand(0).getReg())
.addReg(FrameReg)
.addImm(-Offset);
MI.eraseFromParent();
} else {
MI.getOperand(FIOperandNum).ChangeToRegister(FrameReg, /*isDef=*/false);
MI.getOperand(FIOperandNum + 1).ChangeToImmediate(Offset);
}
}
bool LanaiRegisterInfo::hasBasePointer(const MachineFunction &MF) const {
const MachineFrameInfo &MFI = MF.getFrameInfo();
// When we need stack realignment and there are dynamic allocas, we can't
// reference off of the stack pointer, so we reserve a base pointer.
if (needsStackRealignment(MF) && MFI.hasVarSizedObjects())
return true;
return false;
}
unsigned LanaiRegisterInfo::getRARegister() const { return Lanai::RCA; }
unsigned
LanaiRegisterInfo::getFrameRegister(const MachineFunction & /*MF*/) const {
return Lanai::FP;
}
unsigned LanaiRegisterInfo::getBaseRegister() const { return Lanai::R14; }
const uint32_t *
LanaiRegisterInfo::getCallPreservedMask(const MachineFunction & /*MF*/,
CallingConv::ID /*CC*/) const {
return CSR_RegMask;
}