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llvm-project/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp

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//===- AArch64InstrInfo.cpp - AArch64 Instruction Information -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the AArch64 implementation of the TargetInstrInfo class.
//
//===----------------------------------------------------------------------===//
#include "AArch64.h"
#include "AArch64InstrInfo.h"
#include "AArch64MachineFunctionInfo.h"
#include "AArch64TargetMachine.h"
#include "MCTargetDesc/AArch64MCTargetDesc.h"
#include "Utils/AArch64BaseInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/TargetRegistry.h"
#include <algorithm>
#define GET_INSTRINFO_CTOR
#include "AArch64GenInstrInfo.inc"
using namespace llvm;
AArch64InstrInfo::AArch64InstrInfo(const AArch64Subtarget &STI)
: AArch64GenInstrInfo(AArch64::ADJCALLSTACKDOWN, AArch64::ADJCALLSTACKUP),
RI(*this, STI), Subtarget(STI) {}
void AArch64InstrInfo::copyPhysReg(MachineBasicBlock &MBB,
MachineBasicBlock::iterator I, DebugLoc DL,
unsigned DestReg, unsigned SrcReg,
bool KillSrc) const {
unsigned Opc = 0;
unsigned ZeroReg = 0;
if (DestReg == AArch64::XSP || SrcReg == AArch64::XSP) {
// E.g. ADD xDst, xsp, #0 (, lsl #0)
BuildMI(MBB, I, DL, get(AArch64::ADDxxi_lsl0_s), DestReg)
.addReg(SrcReg)
.addImm(0);
return;
} else if (DestReg == AArch64::WSP || SrcReg == AArch64::WSP) {
// E.g. ADD wDST, wsp, #0 (, lsl #0)
BuildMI(MBB, I, DL, get(AArch64::ADDwwi_lsl0_s), DestReg)
.addReg(SrcReg)
.addImm(0);
return;
} else if (DestReg == AArch64::NZCV) {
assert(AArch64::GPR64RegClass.contains(SrcReg));
// E.g. MSR NZCV, xDST
BuildMI(MBB, I, DL, get(AArch64::MSRix))
.addImm(A64SysReg::NZCV)
.addReg(SrcReg);
} else if (SrcReg == AArch64::NZCV) {
assert(AArch64::GPR64RegClass.contains(DestReg));
// E.g. MRS xDST, NZCV
BuildMI(MBB, I, DL, get(AArch64::MRSxi), DestReg)
.addImm(A64SysReg::NZCV);
} else if (AArch64::GPR64RegClass.contains(DestReg)) {
assert(AArch64::GPR64RegClass.contains(SrcReg));
Opc = AArch64::ORRxxx_lsl;
ZeroReg = AArch64::XZR;
} else if (AArch64::GPR32RegClass.contains(DestReg)) {
assert(AArch64::GPR32RegClass.contains(SrcReg));
Opc = AArch64::ORRwww_lsl;
ZeroReg = AArch64::WZR;
} else if (AArch64::FPR32RegClass.contains(DestReg)) {
assert(AArch64::FPR32RegClass.contains(SrcReg));
BuildMI(MBB, I, DL, get(AArch64::FMOVss), DestReg)
.addReg(SrcReg);
return;
} else if (AArch64::FPR64RegClass.contains(DestReg)) {
assert(AArch64::FPR64RegClass.contains(SrcReg));
BuildMI(MBB, I, DL, get(AArch64::FMOVdd), DestReg)
.addReg(SrcReg);
return;
} else if (AArch64::FPR128RegClass.contains(DestReg)) {
assert(AArch64::FPR128RegClass.contains(SrcReg));
// FIXME: there's no good way to do this, at least without NEON:
// + There's no single move instruction for q-registers
// + We can't create a spill slot and use normal STR/LDR because stack
// allocation has already happened
// + We can't go via X-registers with FMOV because register allocation has
// already happened.
// This may not be efficient, but at least it works.
BuildMI(MBB, I, DL, get(AArch64::LSFP128_PreInd_STR), AArch64::XSP)
.addReg(SrcReg)
.addReg(AArch64::XSP)
.addImm(0x1ff & -16);
BuildMI(MBB, I, DL, get(AArch64::LSFP128_PostInd_LDR), DestReg)
.addReg(AArch64::XSP, RegState::Define)
.addReg(AArch64::XSP)
.addImm(16);
return;
} else {
llvm_unreachable("Unknown register class in copyPhysReg");
}
// E.g. ORR xDst, xzr, xSrc, lsl #0
BuildMI(MBB, I, DL, get(Opc), DestReg)
.addReg(ZeroReg)
.addReg(SrcReg)
.addImm(0);
}
MachineInstr *
AArch64InstrInfo::emitFrameIndexDebugValue(MachineFunction &MF, int FrameIx,
uint64_t Offset, const MDNode *MDPtr,
DebugLoc DL) const {
MachineInstrBuilder MIB = BuildMI(MF, DL, get(AArch64::DBG_VALUE))
.addFrameIndex(FrameIx).addImm(0)
.addImm(Offset)
.addMetadata(MDPtr);
return &*MIB;
}
/// Does the Opcode represent a conditional branch that we can remove and re-add
/// at the end of a basic block?
static bool isCondBranch(unsigned Opc) {
return Opc == AArch64::Bcc || Opc == AArch64::CBZw || Opc == AArch64::CBZx ||
Opc == AArch64::CBNZw || Opc == AArch64::CBNZx ||
Opc == AArch64::TBZwii || Opc == AArch64::TBZxii ||
Opc == AArch64::TBNZwii || Opc == AArch64::TBNZxii;
}
/// Takes apart a given conditional branch MachineInstr (see isCondBranch),
/// setting TBB to the destination basic block and populating the Cond vector
/// with data necessary to recreate the conditional branch at a later
/// date. First element will be the opcode, and subsequent ones define the
/// conditions being branched on in an instruction-specific manner.
static void classifyCondBranch(MachineInstr *I, MachineBasicBlock *&TBB,
SmallVectorImpl<MachineOperand> &Cond) {
switch(I->getOpcode()) {
case AArch64::Bcc:
case AArch64::CBZw:
case AArch64::CBZx:
case AArch64::CBNZw:
case AArch64::CBNZx:
// These instructions just have one predicate operand in position 0 (either
// a condition code or a register being compared).
Cond.push_back(MachineOperand::CreateImm(I->getOpcode()));
Cond.push_back(I->getOperand(0));
TBB = I->getOperand(1).getMBB();
return;
case AArch64::TBZwii:
case AArch64::TBZxii:
case AArch64::TBNZwii:
case AArch64::TBNZxii:
// These have two predicate operands: a register and a bit position.
Cond.push_back(MachineOperand::CreateImm(I->getOpcode()));
Cond.push_back(I->getOperand(0));
Cond.push_back(I->getOperand(1));
TBB = I->getOperand(2).getMBB();
return;
default:
llvm_unreachable("Unknown conditional branch to classify");
}
}
bool
AArch64InstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,MachineBasicBlock *&TBB,
MachineBasicBlock *&FBB,
SmallVectorImpl<MachineOperand> &Cond,
bool AllowModify) const {
// If the block has no terminators, it just falls into the block after it.
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin())
return false;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return false;
--I;
}
if (!isUnpredicatedTerminator(I))
return false;
// Get the last instruction in the block.
MachineInstr *LastInst = I;
// If there is only one terminator instruction, process it.
unsigned LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
if (LastOpc == AArch64::Bimm) {
TBB = LastInst->getOperand(0).getMBB();
return false;
}
if (isCondBranch(LastOpc)) {
classifyCondBranch(LastInst, TBB, Cond);
return false;
}
return true; // Can't handle indirect branch.
}
// Get the instruction before it if it is a terminator.
MachineInstr *SecondLastInst = I;
unsigned SecondLastOpc = SecondLastInst->getOpcode();
// If AllowModify is true and the block ends with two or more unconditional
// branches, delete all but the first unconditional branch.
if (AllowModify && LastOpc == AArch64::Bimm) {
while (SecondLastOpc == AArch64::Bimm) {
LastInst->eraseFromParent();
LastInst = SecondLastInst;
LastOpc = LastInst->getOpcode();
if (I == MBB.begin() || !isUnpredicatedTerminator(--I)) {
// Return now the only terminator is an unconditional branch.
TBB = LastInst->getOperand(0).getMBB();
return false;
} else {
SecondLastInst = I;
SecondLastOpc = SecondLastInst->getOpcode();
}
}
}
// If there are three terminators, we don't know what sort of block this is.
if (SecondLastInst && I != MBB.begin() && isUnpredicatedTerminator(--I))
return true;
// If the block ends with a B and a Bcc, handle it.
if (LastOpc == AArch64::Bimm) {
if (SecondLastOpc == AArch64::Bcc) {
TBB = SecondLastInst->getOperand(1).getMBB();
Cond.push_back(MachineOperand::CreateImm(AArch64::Bcc));
Cond.push_back(SecondLastInst->getOperand(0));
FBB = LastInst->getOperand(0).getMBB();
return false;
} else if (isCondBranch(SecondLastOpc)) {
classifyCondBranch(SecondLastInst, TBB, Cond);
FBB = LastInst->getOperand(0).getMBB();
return false;
}
}
// If the block ends with two unconditional branches, handle it. The second
// one is not executed, so remove it.
if (SecondLastOpc == AArch64::Bimm && LastOpc == AArch64::Bimm) {
TBB = SecondLastInst->getOperand(0).getMBB();
I = LastInst;
if (AllowModify)
I->eraseFromParent();
return false;
}
// Otherwise, can't handle this.
return true;
}
bool AArch64InstrInfo::ReverseBranchCondition(
SmallVectorImpl<MachineOperand> &Cond) const {
switch (Cond[0].getImm()) {
case AArch64::Bcc: {
A64CC::CondCodes CC = static_cast<A64CC::CondCodes>(Cond[1].getImm());
CC = A64InvertCondCode(CC);
Cond[1].setImm(CC);
return false;
}
case AArch64::CBZw:
Cond[0].setImm(AArch64::CBNZw);
return false;
case AArch64::CBZx:
Cond[0].setImm(AArch64::CBNZx);
return false;
case AArch64::CBNZw:
Cond[0].setImm(AArch64::CBZw);
return false;
case AArch64::CBNZx:
Cond[0].setImm(AArch64::CBZx);
return false;
case AArch64::TBZwii:
Cond[0].setImm(AArch64::TBNZwii);
return false;
case AArch64::TBZxii:
Cond[0].setImm(AArch64::TBNZxii);
return false;
case AArch64::TBNZwii:
Cond[0].setImm(AArch64::TBZwii);
return false;
case AArch64::TBNZxii:
Cond[0].setImm(AArch64::TBZxii);
return false;
default:
llvm_unreachable("Unknown branch type");
}
}
unsigned
AArch64InstrInfo::InsertBranch(MachineBasicBlock &MBB, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
const SmallVectorImpl<MachineOperand> &Cond,
DebugLoc DL) const {
if (FBB == 0 && Cond.empty()) {
BuildMI(&MBB, DL, get(AArch64::Bimm)).addMBB(TBB);
return 1;
} else if (FBB == 0) {
MachineInstrBuilder MIB = BuildMI(&MBB, DL, get(Cond[0].getImm()));
for (int i = 1, e = Cond.size(); i != e; ++i)
MIB.addOperand(Cond[i]);
MIB.addMBB(TBB);
return 1;
}
MachineInstrBuilder MIB = BuildMI(&MBB, DL, get(Cond[0].getImm()));
for (int i = 1, e = Cond.size(); i != e; ++i)
MIB.addOperand(Cond[i]);
MIB.addMBB(TBB);
BuildMI(&MBB, DL, get(AArch64::Bimm)).addMBB(FBB);
return 2;
}
unsigned AArch64InstrInfo::RemoveBranch(MachineBasicBlock &MBB) const {
MachineBasicBlock::iterator I = MBB.end();
if (I == MBB.begin()) return 0;
--I;
while (I->isDebugValue()) {
if (I == MBB.begin())
return 0;
--I;
}
if (I->getOpcode() != AArch64::Bimm && !isCondBranch(I->getOpcode()))
return 0;
// Remove the branch.
I->eraseFromParent();
I = MBB.end();
if (I == MBB.begin()) return 1;
--I;
if (!isCondBranch(I->getOpcode()))
return 1;
// Remove the branch.
I->eraseFromParent();
return 2;
}
bool
AArch64InstrInfo::expandPostRAPseudo(MachineBasicBlock::iterator MBBI) const {
MachineInstr &MI = *MBBI;
MachineBasicBlock &MBB = *MI.getParent();
unsigned Opcode = MI.getOpcode();
switch (Opcode) {
case AArch64::TLSDESC_BLRx: {
MachineInstr *NewMI =
BuildMI(MBB, MBBI, MI.getDebugLoc(), get(AArch64::TLSDESCCALL))
.addOperand(MI.getOperand(1));
MI.setDesc(get(AArch64::BLRx));
llvm::finalizeBundle(MBB, NewMI, *++MBBI);
return true;
}
default:
return false;
}
return false;
}
void
AArch64InstrInfo::storeRegToStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned SrcReg, bool isKill,
int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL = MBB.findDebugLoc(MBBI);
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FrameIdx);
MachineMemOperand *MMO
= MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx),
MachineMemOperand::MOStore,
MFI.getObjectSize(FrameIdx),
Align);
unsigned StoreOp = 0;
if (RC->hasType(MVT::i64) || RC->hasType(MVT::i32)) {
switch(RC->getSize()) {
case 4: StoreOp = AArch64::LS32_STR; break;
case 8: StoreOp = AArch64::LS64_STR; break;
default:
llvm_unreachable("Unknown size for regclass");
}
} else {
assert((RC->hasType(MVT::f32) || RC->hasType(MVT::f64) ||
RC->hasType(MVT::f128))
&& "Expected integer or floating type for store");
switch (RC->getSize()) {
case 4: StoreOp = AArch64::LSFP32_STR; break;
case 8: StoreOp = AArch64::LSFP64_STR; break;
case 16: StoreOp = AArch64::LSFP128_STR; break;
default:
llvm_unreachable("Unknown size for regclass");
}
}
MachineInstrBuilder NewMI = BuildMI(MBB, MBBI, DL, get(StoreOp));
NewMI.addReg(SrcReg, getKillRegState(isKill))
.addFrameIndex(FrameIdx)
.addImm(0)
.addMemOperand(MMO);
}
void
AArch64InstrInfo::loadRegFromStackSlot(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
unsigned DestReg, int FrameIdx,
const TargetRegisterClass *RC,
const TargetRegisterInfo *TRI) const {
DebugLoc DL = MBB.findDebugLoc(MBBI);
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
unsigned Align = MFI.getObjectAlignment(FrameIdx);
MachineMemOperand *MMO
= MF.getMachineMemOperand(MachinePointerInfo::getFixedStack(FrameIdx),
MachineMemOperand::MOLoad,
MFI.getObjectSize(FrameIdx),
Align);
unsigned LoadOp = 0;
if (RC->hasType(MVT::i64) || RC->hasType(MVT::i32)) {
switch(RC->getSize()) {
case 4: LoadOp = AArch64::LS32_LDR; break;
case 8: LoadOp = AArch64::LS64_LDR; break;
default:
llvm_unreachable("Unknown size for regclass");
}
} else {
assert((RC->hasType(MVT::f32) || RC->hasType(MVT::f64)
|| RC->hasType(MVT::f128))
&& "Expected integer or floating type for store");
switch (RC->getSize()) {
case 4: LoadOp = AArch64::LSFP32_LDR; break;
case 8: LoadOp = AArch64::LSFP64_LDR; break;
case 16: LoadOp = AArch64::LSFP128_LDR; break;
default:
llvm_unreachable("Unknown size for regclass");
}
}
MachineInstrBuilder NewMI = BuildMI(MBB, MBBI, DL, get(LoadOp), DestReg);
NewMI.addFrameIndex(FrameIdx)
.addImm(0)
.addMemOperand(MMO);
}
unsigned AArch64InstrInfo::estimateRSStackLimit(MachineFunction &MF) const {
unsigned Limit = (1 << 16) - 1;
for (MachineFunction::iterator BB = MF.begin(),E = MF.end(); BB != E; ++BB) {
for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
if (!I->getOperand(i).isFI()) continue;
// When using ADDxxi_lsl0_s to get the address of a stack object, 0xfff
// is the largest offset guaranteed to fit in the immediate offset.
if (I->getOpcode() == AArch64::ADDxxi_lsl0_s) {
Limit = std::min(Limit, 0xfffu);
break;
}
int AccessScale, MinOffset, MaxOffset;
getAddressConstraints(*I, AccessScale, MinOffset, MaxOffset);
Limit = std::min(Limit, static_cast<unsigned>(MaxOffset));
break; // At most one FI per instruction
}
}
}
return Limit;
}
void AArch64InstrInfo::getAddressConstraints(const MachineInstr &MI,
int &AccessScale, int &MinOffset,
int &MaxOffset) const {
switch (MI.getOpcode()) {
default: llvm_unreachable("Unkown load/store kind");
case TargetOpcode::DBG_VALUE:
AccessScale = 1;
MinOffset = INT_MIN;
MaxOffset = INT_MAX;
return;
case AArch64::LS8_LDR: case AArch64::LS8_STR:
case AArch64::LSFP8_LDR: case AArch64::LSFP8_STR:
case AArch64::LDRSBw:
case AArch64::LDRSBx:
AccessScale = 1;
MinOffset = 0;
MaxOffset = 0xfff;
return;
case AArch64::LS16_LDR: case AArch64::LS16_STR:
case AArch64::LSFP16_LDR: case AArch64::LSFP16_STR:
case AArch64::LDRSHw:
case AArch64::LDRSHx:
AccessScale = 2;
MinOffset = 0;
MaxOffset = 0xfff * AccessScale;
return;
case AArch64::LS32_LDR: case AArch64::LS32_STR:
case AArch64::LSFP32_LDR: case AArch64::LSFP32_STR:
case AArch64::LDRSWx:
case AArch64::LDPSWx:
AccessScale = 4;
MinOffset = 0;
MaxOffset = 0xfff * AccessScale;
return;
case AArch64::LS64_LDR: case AArch64::LS64_STR:
case AArch64::LSFP64_LDR: case AArch64::LSFP64_STR:
case AArch64::PRFM:
AccessScale = 8;
MinOffset = 0;
MaxOffset = 0xfff * AccessScale;
return;
case AArch64::LSFP128_LDR: case AArch64::LSFP128_STR:
AccessScale = 16;
MinOffset = 0;
MaxOffset = 0xfff * AccessScale;
return;
case AArch64::LSPair32_LDR: case AArch64::LSPair32_STR:
case AArch64::LSFPPair32_LDR: case AArch64::LSFPPair32_STR:
AccessScale = 4;
MinOffset = -0x40 * AccessScale;
MaxOffset = 0x3f * AccessScale;
return;
case AArch64::LSPair64_LDR: case AArch64::LSPair64_STR:
case AArch64::LSFPPair64_LDR: case AArch64::LSFPPair64_STR:
AccessScale = 8;
MinOffset = -0x40 * AccessScale;
MaxOffset = 0x3f * AccessScale;
return;
case AArch64::LSFPPair128_LDR: case AArch64::LSFPPair128_STR:
AccessScale = 16;
MinOffset = -0x40 * AccessScale;
MaxOffset = 0x3f * AccessScale;
return;
}
}
unsigned AArch64InstrInfo::getInstSizeInBytes(const MachineInstr &MI) const {
const MCInstrDesc &MCID = MI.getDesc();
const MachineBasicBlock &MBB = *MI.getParent();
const MachineFunction &MF = *MBB.getParent();
const MCAsmInfo &MAI = *MF.getTarget().getMCAsmInfo();
if (MCID.getSize())
return MCID.getSize();
if (MI.getOpcode() == AArch64::INLINEASM)
return getInlineAsmLength(MI.getOperand(0).getSymbolName(), MAI);
if (MI.isLabel())
return 0;
switch (MI.getOpcode()) {
case TargetOpcode::BUNDLE:
return getInstBundleLength(MI);
case TargetOpcode::IMPLICIT_DEF:
case TargetOpcode::KILL:
case TargetOpcode::PROLOG_LABEL:
case TargetOpcode::EH_LABEL:
case TargetOpcode::DBG_VALUE:
return 0;
case AArch64::CONSTPOOL_ENTRY:
return MI.getOperand(2).getImm();
case AArch64::TLSDESCCALL:
return 0;
default:
llvm_unreachable("Unknown instruction class");
}
}
unsigned AArch64InstrInfo::getInstBundleLength(const MachineInstr &MI) const {
unsigned Size = 0;
MachineBasicBlock::const_instr_iterator I = MI;
MachineBasicBlock::const_instr_iterator E = MI.getParent()->instr_end();
while (++I != E && I->isInsideBundle()) {
assert(!I->isBundle() && "No nested bundle!");
Size += getInstSizeInBytes(*I);
}
return Size;
}
bool llvm::rewriteA64FrameIndex(MachineInstr &MI, unsigned FrameRegIdx,
unsigned FrameReg, int &Offset,
const AArch64InstrInfo &TII) {
MachineBasicBlock &MBB = *MI.getParent();
MachineFunction &MF = *MBB.getParent();
MachineFrameInfo &MFI = *MF.getFrameInfo();
MFI.getObjectOffset(FrameRegIdx);
llvm_unreachable("Unimplemented rewriteFrameIndex");
}
void llvm::emitRegUpdate(MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
DebugLoc dl, const TargetInstrInfo &TII,
unsigned DstReg, unsigned SrcReg, unsigned ScratchReg,
int64_t NumBytes, MachineInstr::MIFlag MIFlags) {
if (NumBytes == 0 && DstReg == SrcReg)
return;
else if (abs(NumBytes) & ~0xffffff) {
// Generically, we have to materialize the offset into a temporary register
// and subtract it. There are a couple of ways this could be done, for now
// we'll go for a literal-pool load.
MachineFunction &MF = *MBB.getParent();
MachineConstantPool *MCP = MF.getConstantPool();
const Constant *C
= ConstantInt::get(Type::getInt64Ty(MF.getFunction()->getContext()),
abs(NumBytes));
unsigned CPI = MCP->getConstantPoolIndex(C, 8);
// LDR xTMP, .LITPOOL
BuildMI(MBB, MBBI, dl, TII.get(AArch64::LDRx_lit), ScratchReg)
.addConstantPoolIndex(CPI)
.setMIFlag(MIFlags);
// ADD DST, SRC, xTMP (, lsl #0)
unsigned AddOp = NumBytes > 0 ? AArch64::ADDxxx_uxtx : AArch64::SUBxxx_uxtx;
BuildMI(MBB, MBBI, dl, TII.get(AddOp), DstReg)
.addReg(SrcReg, RegState::Kill)
.addReg(ScratchReg, RegState::Kill)
.addImm(0)
.setMIFlag(MIFlags);
return;
}
// Now we know that the adjustment can be done in at most two add/sub
// (immediate) instructions, which is always more efficient than a
// literal-pool load, or even a hypothetical movz/movk/add sequence
// Decide whether we're doing addition or subtraction
unsigned LowOp, HighOp;
if (NumBytes >= 0) {
LowOp = AArch64::ADDxxi_lsl0_s;
HighOp = AArch64::ADDxxi_lsl12_s;
} else {
LowOp = AArch64::SUBxxi_lsl0_s;
HighOp = AArch64::SUBxxi_lsl12_s;
NumBytes = abs(NumBytes);
}
// If we're here, at the very least a move needs to be produced, which just
// happens to be materializable by an ADD.
if ((NumBytes & 0xfff) || NumBytes == 0) {
BuildMI(MBB, MBBI, dl, TII.get(LowOp), DstReg)
.addReg(SrcReg, RegState::Kill)
.addImm(NumBytes & 0xfff)
.setMIFlag(MIFlags);
// Next update should use the register we've just defined.
SrcReg = DstReg;
}
if (NumBytes & 0xfff000) {
BuildMI(MBB, MBBI, dl, TII.get(HighOp), DstReg)
.addReg(SrcReg, RegState::Kill)
.addImm(NumBytes >> 12)
.setMIFlag(MIFlags);
}
}
void llvm::emitSPUpdate(MachineBasicBlock &MBB, MachineBasicBlock::iterator MI,
DebugLoc dl, const TargetInstrInfo &TII,
unsigned ScratchReg, int64_t NumBytes,
MachineInstr::MIFlag MIFlags) {
emitRegUpdate(MBB, MI, dl, TII, AArch64::XSP, AArch64::XSP, AArch64::X16,
NumBytes, MIFlags);
}
namespace {
struct LDTLSCleanup : public MachineFunctionPass {
static char ID;
LDTLSCleanup() : MachineFunctionPass(ID) {}
virtual bool runOnMachineFunction(MachineFunction &MF) {
AArch64MachineFunctionInfo* MFI
= MF.getInfo<AArch64MachineFunctionInfo>();
if (MFI->getNumLocalDynamicTLSAccesses() < 2) {
// No point folding accesses if there isn't at least two.
return false;
}
MachineDominatorTree *DT = &getAnalysis<MachineDominatorTree>();
return VisitNode(DT->getRootNode(), 0);
}
// Visit the dominator subtree rooted at Node in pre-order.
// If TLSBaseAddrReg is non-null, then use that to replace any
// TLS_base_addr instructions. Otherwise, create the register
// when the first such instruction is seen, and then use it
// as we encounter more instructions.
bool VisitNode(MachineDomTreeNode *Node, unsigned TLSBaseAddrReg) {
MachineBasicBlock *BB = Node->getBlock();
bool Changed = false;
// Traverse the current block.
for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;
++I) {
switch (I->getOpcode()) {
case AArch64::TLSDESC_BLRx:
// Make sure it's a local dynamic access.
if (!I->getOperand(1).isSymbol() ||
strcmp(I->getOperand(1).getSymbolName(), "_TLS_MODULE_BASE_"))
break;
if (TLSBaseAddrReg)
I = ReplaceTLSBaseAddrCall(I, TLSBaseAddrReg);
else
I = SetRegister(I, &TLSBaseAddrReg);
Changed = true;
break;
default:
break;
}
}
// Visit the children of this block in the dominator tree.
for (MachineDomTreeNode::iterator I = Node->begin(), E = Node->end();
I != E; ++I) {
Changed |= VisitNode(*I, TLSBaseAddrReg);
}
return Changed;
}
// Replace the TLS_base_addr instruction I with a copy from
// TLSBaseAddrReg, returning the new instruction.
MachineInstr *ReplaceTLSBaseAddrCall(MachineInstr *I,
unsigned TLSBaseAddrReg) {
MachineFunction *MF = I->getParent()->getParent();
const AArch64TargetMachine *TM =
static_cast<const AArch64TargetMachine *>(&MF->getTarget());
const AArch64InstrInfo *TII = TM->getInstrInfo();
// Insert a Copy from TLSBaseAddrReg to x0, which is where the rest of the
// code sequence assumes the address will be.
MachineInstr *Copy = BuildMI(*I->getParent(), I, I->getDebugLoc(),
TII->get(TargetOpcode::COPY),
AArch64::X0)
.addReg(TLSBaseAddrReg);
// Erase the TLS_base_addr instruction.
I->eraseFromParent();
return Copy;
}
// Create a virtal register in *TLSBaseAddrReg, and populate it by
// inserting a copy instruction after I. Returns the new instruction.
MachineInstr *SetRegister(MachineInstr *I, unsigned *TLSBaseAddrReg) {
MachineFunction *MF = I->getParent()->getParent();
const AArch64TargetMachine *TM =
static_cast<const AArch64TargetMachine *>(&MF->getTarget());
const AArch64InstrInfo *TII = TM->getInstrInfo();
// Create a virtual register for the TLS base address.
MachineRegisterInfo &RegInfo = MF->getRegInfo();
*TLSBaseAddrReg = RegInfo.createVirtualRegister(&AArch64::GPR64RegClass);
// Insert a copy from X0 to TLSBaseAddrReg for later.
MachineInstr *Next = I->getNextNode();
MachineInstr *Copy = BuildMI(*I->getParent(), Next, I->getDebugLoc(),
TII->get(TargetOpcode::COPY),
*TLSBaseAddrReg)
.addReg(AArch64::X0);
return Copy;
}
virtual const char *getPassName() const {
return "Local Dynamic TLS Access Clean-up";
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesCFG();
AU.addRequired<MachineDominatorTree>();
MachineFunctionPass::getAnalysisUsage(AU);
}
};
}
char LDTLSCleanup::ID = 0;
FunctionPass*
llvm::createAArch64CleanupLocalDynamicTLSPass() { return new LDTLSCleanup(); }
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