MachineBasicBlock.cpp [plain text]
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SlotIndexes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/ModuleSlotTracker.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include <algorithm>
using namespace llvm;
#define DEBUG_TYPE "codegen"
MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb)
: BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false),
AddressTaken(false), CachedMCSymbol(nullptr) {
Insts.Parent = this;
}
MachineBasicBlock::~MachineBasicBlock() {
}
MCSymbol *MachineBasicBlock::getSymbol() const {
if (!CachedMCSymbol) {
const MachineFunction *MF = getParent();
MCContext &Ctx = MF->getContext();
const char *Prefix = Ctx.getAsmInfo()->getPrivateLabelPrefix();
CachedMCSymbol = Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" +
Twine(MF->getFunctionNumber()) +
"_" + Twine(getNumber()));
}
return CachedMCSymbol;
}
raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineBasicBlock &MBB) {
MBB.print(OS);
return OS;
}
void ilist_traits<MachineBasicBlock>::addNodeToList(MachineBasicBlock *N) {
MachineFunction &MF = *N->getParent();
N->Number = MF.addToMBBNumbering(N);
MachineRegisterInfo &RegInfo = MF.getRegInfo();
for (MachineBasicBlock::instr_iterator
I = N->instr_begin(), E = N->instr_end(); I != E; ++I)
I->AddRegOperandsToUseLists(RegInfo);
}
void ilist_traits<MachineBasicBlock>::removeNodeFromList(MachineBasicBlock *N) {
N->getParent()->removeFromMBBNumbering(N->Number);
N->Number = -1;
}
void ilist_traits<MachineInstr>::addNodeToList(MachineInstr *N) {
assert(!N->getParent() && "machine instruction already in a basic block");
N->setParent(Parent);
MachineFunction *MF = Parent->getParent();
N->AddRegOperandsToUseLists(MF->getRegInfo());
}
void ilist_traits<MachineInstr>::removeNodeFromList(MachineInstr *N) {
assert(N->getParent() && "machine instruction not in a basic block");
if (MachineFunction *MF = N->getParent()->getParent())
N->RemoveRegOperandsFromUseLists(MF->getRegInfo());
N->setParent(nullptr);
}
void ilist_traits<MachineInstr>::
transferNodesFromList(ilist_traits<MachineInstr> &fromList,
ilist_iterator<MachineInstr> first,
ilist_iterator<MachineInstr> last) {
assert(Parent->getParent() == fromList.Parent->getParent() &&
"MachineInstr parent mismatch!");
if (Parent == fromList.Parent) return;
for (; first != last; ++first)
first->setParent(Parent);
}
void ilist_traits<MachineInstr>::deleteNode(MachineInstr* MI) {
assert(!MI->getParent() && "MI is still in a block!");
Parent->getParent()->DeleteMachineInstr(MI);
}
MachineBasicBlock::iterator MachineBasicBlock::getFirstNonPHI() {
instr_iterator I = instr_begin(), E = instr_end();
while (I != E && I->isPHI())
++I;
assert((I == E || !I->isInsideBundle()) &&
"First non-phi MI cannot be inside a bundle!");
return I;
}
MachineBasicBlock::iterator
MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) {
iterator E = end();
while (I != E && (I->isPHI() || I->isPosition() || I->isDebugValue()))
++I;
assert((I == E || !I->isInsideBundle()) &&
"First non-phi / non-label instruction is inside a bundle!");
return I;
}
MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
iterator B = begin(), E = end(), I = E;
while (I != B && ((--I)->isTerminator() || I->isDebugValue()))
;
while (I != E && !I->isTerminator())
++I;
return I;
}
MachineBasicBlock::const_iterator
MachineBasicBlock::getFirstTerminator() const {
const_iterator B = begin(), E = end(), I = E;
while (I != B && ((--I)->isTerminator() || I->isDebugValue()))
;
while (I != E && !I->isTerminator())
++I;
return I;
}
MachineBasicBlock::instr_iterator MachineBasicBlock::getFirstInstrTerminator() {
instr_iterator B = instr_begin(), E = instr_end(), I = E;
while (I != B && ((--I)->isTerminator() || I->isDebugValue()))
;
while (I != E && !I->isTerminator())
++I;
return I;
}
MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
instr_iterator B = instr_begin(), I = instr_end();
while (I != B) {
--I;
if (I->isDebugValue() || I->isInsideBundle())
continue;
return I;
}
return end();
}
MachineBasicBlock::const_iterator
MachineBasicBlock::getLastNonDebugInstr() const {
const_instr_iterator B = instr_begin(), I = instr_end();
while (I != B) {
--I;
if (I->isDebugValue() || I->isInsideBundle())
continue;
return I;
}
return end();
}
const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const {
if (succ_size() > 2)
return nullptr;
for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I)
if ((*I)->isLandingPad())
return *I;
return nullptr;
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void MachineBasicBlock::dump() const {
print(dbgs());
}
#endif
StringRef MachineBasicBlock::getName() const {
if (const BasicBlock *LBB = getBasicBlock())
return LBB->getName();
else
return "(null)";
}
std::string MachineBasicBlock::getFullName() const {
std::string Name;
if (getParent())
Name = (getParent()->getName() + ":").str();
if (getBasicBlock())
Name += getBasicBlock()->getName();
else
Name += (Twine("BB") + Twine(getNumber())).str();
return Name;
}
void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const {
const MachineFunction *MF = getParent();
if (!MF) {
OS << "Can't print out MachineBasicBlock because parent MachineFunction"
<< " is null\n";
return;
}
const Function *F = MF->getFunction();
const Module *M = F ? F->getParent() : nullptr;
ModuleSlotTracker MST(M);
print(OS, MST, Indexes);
}
void MachineBasicBlock::print(raw_ostream &OS, ModuleSlotTracker &MST,
SlotIndexes *Indexes) const {
const MachineFunction *MF = getParent();
if (!MF) {
OS << "Can't print out MachineBasicBlock because parent MachineFunction"
<< " is null\n";
return;
}
if (Indexes)
OS << Indexes->getMBBStartIdx(this) << '\t';
OS << "BB#" << getNumber() << ": ";
const char *Comma = "";
if (const BasicBlock *LBB = getBasicBlock()) {
OS << Comma << "derived from LLVM BB ";
LBB->printAsOperand(OS, false, MST);
Comma = ", ";
}
if (isLandingPad()) { OS << Comma << "EH LANDING PAD"; Comma = ", "; }
if (hasAddressTaken()) { OS << Comma << "ADDRESS TAKEN"; Comma = ", "; }
if (Alignment)
OS << Comma << "Align " << Alignment << " (" << (1u << Alignment)
<< " bytes)";
OS << '\n';
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
if (!livein_empty()) {
if (Indexes) OS << '\t';
OS << " Live Ins:";
for (livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I)
OS << ' ' << PrintReg(*I, TRI);
OS << '\n';
}
if (!pred_empty()) {
if (Indexes) OS << '\t';
OS << " Predecessors according to CFG:";
for (const_pred_iterator PI = pred_begin(), E = pred_end(); PI != E; ++PI)
OS << " BB#" << (*PI)->getNumber();
OS << '\n';
}
for (const_instr_iterator I = instr_begin(); I != instr_end(); ++I) {
if (Indexes) {
if (Indexes->hasIndex(I))
OS << Indexes->getInstructionIndex(I);
OS << '\t';
}
OS << '\t';
if (I->isInsideBundle())
OS << " * ";
I->print(OS, MST);
}
if (!succ_empty()) {
if (Indexes) OS << '\t';
OS << " Successors according to CFG:";
for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI) {
OS << " BB#" << (*SI)->getNumber();
if (!Weights.empty())
OS << '(' << *getWeightIterator(SI) << ')';
}
OS << '\n';
}
}
void MachineBasicBlock::printAsOperand(raw_ostream &OS, bool ) const {
OS << "BB#" << getNumber();
}
void MachineBasicBlock::removeLiveIn(unsigned Reg) {
std::vector<unsigned>::iterator I =
std::find(LiveIns.begin(), LiveIns.end(), Reg);
if (I != LiveIns.end())
LiveIns.erase(I);
}
bool MachineBasicBlock::isLiveIn(unsigned Reg) const {
livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
return I != livein_end();
}
unsigned
MachineBasicBlock::addLiveIn(unsigned PhysReg, const TargetRegisterClass *RC) {
assert(getParent() && "MBB must be inserted in function");
assert(TargetRegisterInfo::isPhysicalRegister(PhysReg) && "Expected physreg");
assert(RC && "Register class is required");
assert((isLandingPad() || this == &getParent()->front()) &&
"Only the entry block and landing pads can have physreg live ins");
bool LiveIn = isLiveIn(PhysReg);
iterator I = SkipPHIsAndLabels(begin()), E = end();
MachineRegisterInfo &MRI = getParent()->getRegInfo();
const TargetInstrInfo &TII = *getParent()->getSubtarget().getInstrInfo();
if (LiveIn)
for (;I != E && I->isCopy(); ++I)
if (I->getOperand(1).getReg() == PhysReg) {
unsigned VirtReg = I->getOperand(0).getReg();
if (!MRI.constrainRegClass(VirtReg, RC))
llvm_unreachable("Incompatible live-in register class.");
return VirtReg;
}
unsigned VirtReg = MRI.createVirtualRegister(RC);
BuildMI(*this, I, DebugLoc(), TII.get(TargetOpcode::COPY), VirtReg)
.addReg(PhysReg, RegState::Kill);
if (!LiveIn)
addLiveIn(PhysReg);
return VirtReg;
}
void MachineBasicBlock::moveBefore(MachineBasicBlock *NewAfter) {
getParent()->splice(NewAfter, this);
}
void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) {
MachineFunction::iterator BBI = NewBefore;
getParent()->splice(++BBI, this);
}
void MachineBasicBlock::updateTerminator() {
const TargetInstrInfo *TII = getParent()->getSubtarget().getInstrInfo();
if (this->succ_empty()) return;
MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
SmallVector<MachineOperand, 4> Cond;
DebugLoc dl; bool B = TII->AnalyzeBranch(*this, TBB, FBB, Cond);
(void) B;
assert(!B && "UpdateTerminators requires analyzable predecessors!");
if (Cond.empty()) {
if (TBB) {
if (isLayoutSuccessor(TBB))
TII->RemoveBranch(*this);
} else {
for (succ_iterator SI = succ_begin(), SE = succ_end(); SI != SE; ++SI) {
if ((*SI)->isLandingPad())
continue;
assert(!TBB && "Found more than one non-landing-pad successor!");
TBB = *SI;
}
if (!TBB)
return;
if (!isLayoutSuccessor(TBB))
TII->InsertBranch(*this, TBB, nullptr, Cond, dl);
}
} else {
if (FBB) {
if (isLayoutSuccessor(TBB)) {
if (TII->ReverseBranchCondition(Cond))
return;
TII->RemoveBranch(*this);
TII->InsertBranch(*this, FBB, nullptr, Cond, dl);
} else if (isLayoutSuccessor(FBB)) {
TII->RemoveBranch(*this);
TII->InsertBranch(*this, TBB, nullptr, Cond, dl);
}
} else {
MachineBasicBlock *FallthroughBB = nullptr;
for (succ_iterator SI = succ_begin(), SE = succ_end(); SI != SE; ++SI) {
if ((*SI)->isLandingPad() || *SI == TBB)
continue;
assert(!FallthroughBB && "Found more than one fallthrough successor.");
FallthroughBB = *SI;
}
if (!FallthroughBB && canFallThrough()) {
TII->RemoveBranch(*this);
if (!isLayoutSuccessor(TBB))
TII->InsertBranch(*this, TBB, nullptr, Cond, dl);
return;
}
if (isLayoutSuccessor(TBB)) {
if (TII->ReverseBranchCondition(Cond)) {
Cond.clear();
TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl);
return;
}
TII->RemoveBranch(*this);
TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl);
} else if (!isLayoutSuccessor(FallthroughBB)) {
TII->RemoveBranch(*this);
TII->InsertBranch(*this, TBB, FallthroughBB, Cond, dl);
}
}
}
}
void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ, uint32_t weight) {
if (weight != 0 && Weights.empty())
Weights.resize(Successors.size());
if (weight != 0 || !Weights.empty())
Weights.push_back(weight);
Successors.push_back(succ);
succ->addPredecessor(this);
}
void MachineBasicBlock::removeSuccessor(MachineBasicBlock *succ) {
succ->removePredecessor(this);
succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
assert(I != Successors.end() && "Not a current successor!");
if (!Weights.empty()) {
weight_iterator WI = getWeightIterator(I);
Weights.erase(WI);
}
Successors.erase(I);
}
MachineBasicBlock::succ_iterator
MachineBasicBlock::removeSuccessor(succ_iterator I) {
assert(I != Successors.end() && "Not a current successor!");
if (!Weights.empty()) {
weight_iterator WI = getWeightIterator(I);
Weights.erase(WI);
}
(*I)->removePredecessor(this);
return Successors.erase(I);
}
void MachineBasicBlock::replaceSuccessor(MachineBasicBlock *Old,
MachineBasicBlock *New) {
if (Old == New)
return;
succ_iterator E = succ_end();
succ_iterator NewI = E;
succ_iterator OldI = E;
for (succ_iterator I = succ_begin(); I != E; ++I) {
if (*I == Old) {
OldI = I;
if (NewI != E)
break;
}
if (*I == New) {
NewI = I;
if (OldI != E)
break;
}
}
assert(OldI != E && "Old is not a successor of this block");
Old->removePredecessor(this);
if (NewI == E) {
New->addPredecessor(this);
*OldI = New;
return;
}
if (!Weights.empty()) {
weight_iterator OldWI = getWeightIterator(OldI);
*getWeightIterator(NewI) += *OldWI;
Weights.erase(OldWI);
}
Successors.erase(OldI);
}
void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) {
Predecessors.push_back(pred);
}
void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) {
pred_iterator I = std::find(Predecessors.begin(), Predecessors.end(), pred);
assert(I != Predecessors.end() && "Pred is not a predecessor of this block!");
Predecessors.erase(I);
}
void MachineBasicBlock::transferSuccessors(MachineBasicBlock *fromMBB) {
if (this == fromMBB)
return;
while (!fromMBB->succ_empty()) {
MachineBasicBlock *Succ = *fromMBB->succ_begin();
uint32_t Weight = 0;
if (!fromMBB->Weights.empty())
Weight = *fromMBB->Weights.begin();
addSuccessor(Succ, Weight);
fromMBB->removeSuccessor(Succ);
}
}
void
MachineBasicBlock::transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB) {
if (this == fromMBB)
return;
while (!fromMBB->succ_empty()) {
MachineBasicBlock *Succ = *fromMBB->succ_begin();
uint32_t Weight = 0;
if (!fromMBB->Weights.empty())
Weight = *fromMBB->Weights.begin();
addSuccessor(Succ, Weight);
fromMBB->removeSuccessor(Succ);
for (MachineBasicBlock::instr_iterator MI = Succ->instr_begin(),
ME = Succ->instr_end(); MI != ME && MI->isPHI(); ++MI)
for (unsigned i = 2, e = MI->getNumOperands()+1; i != e; i += 2) {
MachineOperand &MO = MI->getOperand(i);
if (MO.getMBB() == fromMBB)
MO.setMBB(this);
}
}
}
bool MachineBasicBlock::isPredecessor(const MachineBasicBlock *MBB) const {
return std::find(pred_begin(), pred_end(), MBB) != pred_end();
}
bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const {
return std::find(succ_begin(), succ_end(), MBB) != succ_end();
}
bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
MachineFunction::const_iterator I(this);
return std::next(I) == MachineFunction::const_iterator(MBB);
}
bool MachineBasicBlock::canFallThrough() {
MachineFunction::iterator Fallthrough = this;
++Fallthrough;
if (Fallthrough == getParent()->end())
return false;
if (!isSuccessor(Fallthrough))
return false;
MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
SmallVector<MachineOperand, 4> Cond;
const TargetInstrInfo *TII = getParent()->getSubtarget().getInstrInfo();
if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) {
return empty() || !back().isBarrier() || TII->isPredicated(&back());
}
if (!TBB) return true;
if (MachineFunction::iterator(TBB) == Fallthrough ||
MachineFunction::iterator(FBB) == Fallthrough)
return true;
if (Cond.empty()) return false;
return FBB == nullptr;
}
MachineBasicBlock *
MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
if (Succ->isLandingPad())
return nullptr;
MachineFunction *MF = getParent();
DebugLoc dl;
if (MF->getTarget().requiresStructuredCFG())
return nullptr;
const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo();
MachineBasicBlock *TBB = nullptr, *FBB = nullptr;
SmallVector<MachineOperand, 4> Cond;
if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
return nullptr;
if (TBB && TBB == FBB) {
DEBUG(dbgs() << "Won't split critical edge after degenerate BB#"
<< getNumber() << '\n');
return nullptr;
}
MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
MF->insert(std::next(MachineFunction::iterator(this)), NMBB);
DEBUG(dbgs() << "Splitting critical edge:"
" BB#" << getNumber()
<< " -- BB#" << NMBB->getNumber()
<< " -- BB#" << Succ->getNumber() << '\n');
LiveIntervals *LIS = P->getAnalysisIfAvailable<LiveIntervals>();
SlotIndexes *Indexes = P->getAnalysisIfAvailable<SlotIndexes>();
if (LIS)
LIS->insertMBBInMaps(NMBB);
else if (Indexes)
Indexes->insertMBBInMaps(NMBB);
LiveVariables *LV = P->getAnalysisIfAvailable<LiveVariables>();
SmallVector<unsigned, 4> KilledRegs;
if (LV)
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I) {
MachineInstr *MI = I;
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
if (!OI->isReg() || OI->getReg() == 0 ||
!OI->isUse() || !OI->isKill() || OI->isUndef())
continue;
unsigned Reg = OI->getReg();
if (TargetRegisterInfo::isPhysicalRegister(Reg) ||
LV->getVarInfo(Reg).removeKill(MI)) {
KilledRegs.push_back(Reg);
DEBUG(dbgs() << "Removing terminator kill: " << *MI);
OI->setIsKill(false);
}
}
}
SmallVector<unsigned, 4> UsedRegs;
if (LIS) {
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I) {
MachineInstr *MI = I;
for (MachineInstr::mop_iterator OI = MI->operands_begin(),
OE = MI->operands_end(); OI != OE; ++OI) {
if (!OI->isReg() || OI->getReg() == 0)
continue;
unsigned Reg = OI->getReg();
if (std::find(UsedRegs.begin(), UsedRegs.end(), Reg) == UsedRegs.end())
UsedRegs.push_back(Reg);
}
}
}
ReplaceUsesOfBlockWith(Succ, NMBB);
SmallVector<MachineInstr*, 4> Terminators;
if (Indexes) {
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I)
Terminators.push_back(I);
}
updateTerminator();
if (Indexes) {
SmallVector<MachineInstr*, 4> NewTerminators;
for (instr_iterator I = getFirstInstrTerminator(), E = instr_end();
I != E; ++I)
NewTerminators.push_back(I);
for (SmallVectorImpl<MachineInstr*>::iterator I = Terminators.begin(),
E = Terminators.end(); I != E; ++I) {
if (std::find(NewTerminators.begin(), NewTerminators.end(), *I) ==
NewTerminators.end())
Indexes->removeMachineInstrFromMaps(*I);
}
}
NMBB->addSuccessor(Succ);
if (!NMBB->isLayoutSuccessor(Succ)) {
Cond.clear();
MF->getSubtarget().getInstrInfo()->InsertBranch(*NMBB, Succ, nullptr, Cond,
dl);
if (Indexes) {
for (instr_iterator I = NMBB->instr_begin(), E = NMBB->instr_end();
I != E; ++I) {
if (Indexes->hasIndex(I))
Indexes->removeMachineInstrFromMaps(I);
Indexes->insertMachineInstrInMaps(I);
}
}
}
for (MachineBasicBlock::instr_iterator
i = Succ->instr_begin(),e = Succ->instr_end();
i != e && i->isPHI(); ++i)
for (unsigned ni = 1, ne = i->getNumOperands(); ni != ne; ni += 2)
if (i->getOperand(ni+1).getMBB() == this)
i->getOperand(ni+1).setMBB(NMBB);
for (MachineBasicBlock::livein_iterator I = Succ->livein_begin(),
E = Succ->livein_end(); I != E; ++I)
NMBB->addLiveIn(*I);
const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo();
if (LV) {
while (!KilledRegs.empty()) {
unsigned Reg = KilledRegs.pop_back_val();
for (instr_iterator I = instr_end(), E = instr_begin(); I != E;) {
if (!(--I)->addRegisterKilled(Reg, TRI, false))
continue;
if (TargetRegisterInfo::isVirtualRegister(Reg))
LV->getVarInfo(Reg).Kills.push_back(I);
DEBUG(dbgs() << "Restored terminator kill: " << *I);
break;
}
}
LV->addNewBlock(NMBB, this, Succ);
}
if (LIS) {
bool isLastMBB =
std::next(MachineFunction::iterator(NMBB)) == getParent()->end();
SlotIndex StartIndex = Indexes->getMBBEndIdx(this);
SlotIndex PrevIndex = StartIndex.getPrevSlot();
SlotIndex EndIndex = Indexes->getMBBEndIdx(NMBB);
SmallSet<unsigned, 8> PHISrcRegs;
for (MachineBasicBlock::instr_iterator
I = Succ->instr_begin(), E = Succ->instr_end();
I != E && I->isPHI(); ++I) {
for (unsigned ni = 1, ne = I->getNumOperands(); ni != ne; ni += 2) {
if (I->getOperand(ni+1).getMBB() == NMBB) {
MachineOperand &MO = I->getOperand(ni);
unsigned Reg = MO.getReg();
PHISrcRegs.insert(Reg);
if (MO.isUndef())
continue;
LiveInterval &LI = LIS->getInterval(Reg);
VNInfo *VNI = LI.getVNInfoAt(PrevIndex);
assert(VNI && "PHI sources should be live out of their predecessors.");
LI.addSegment(LiveInterval::Segment(StartIndex, EndIndex, VNI));
}
}
}
MachineRegisterInfo *MRI = &getParent()->getRegInfo();
for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) {
unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
if (PHISrcRegs.count(Reg) || !LIS->hasInterval(Reg))
continue;
LiveInterval &LI = LIS->getInterval(Reg);
if (!LI.liveAt(PrevIndex))
continue;
bool isLiveOut = LI.liveAt(LIS->getMBBStartIdx(Succ));
if (isLiveOut && isLastMBB) {
VNInfo *VNI = LI.getVNInfoAt(PrevIndex);
assert(VNI && "LiveInterval should have VNInfo where it is live.");
LI.addSegment(LiveInterval::Segment(StartIndex, EndIndex, VNI));
} else if (!isLiveOut && !isLastMBB) {
LI.removeSegment(StartIndex, EndIndex);
}
}
LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs);
}
if (MachineDominatorTree *MDT =
P->getAnalysisIfAvailable<MachineDominatorTree>())
MDT->recordSplitCriticalEdge(this, Succ, NMBB);
if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
if (MachineLoop *TIL = MLI->getLoopFor(this)) {
if (MachineLoop *DestLoop = MLI->getLoopFor(Succ)) {
if (TIL == DestLoop) {
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (TIL->contains(DestLoop)) {
TIL->addBasicBlockToLoop(NMBB, MLI->getBase());
} else if (DestLoop->contains(TIL)) {
DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
} else {
assert(DestLoop->getHeader() == Succ &&
"Should not create irreducible loops!");
if (MachineLoop *P = DestLoop->getParentLoop())
P->addBasicBlockToLoop(NMBB, MLI->getBase());
}
}
}
return NMBB;
}
static void unbundleSingleMI(MachineInstr *MI) {
if (MI->isBundledWithSucc() && !MI->isBundledWithPred())
MI->unbundleFromSucc();
if (MI->isBundledWithPred() && !MI->isBundledWithSucc())
MI->unbundleFromPred();
}
MachineBasicBlock::instr_iterator
MachineBasicBlock::erase(MachineBasicBlock::instr_iterator I) {
unbundleSingleMI(I);
return Insts.erase(I);
}
MachineInstr *MachineBasicBlock::remove_instr(MachineInstr *MI) {
unbundleSingleMI(MI);
MI->clearFlag(MachineInstr::BundledPred);
MI->clearFlag(MachineInstr::BundledSucc);
return Insts.remove(MI);
}
MachineBasicBlock::instr_iterator
MachineBasicBlock::insert(instr_iterator I, MachineInstr *MI) {
assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
"Cannot insert instruction with bundle flags");
if (I != instr_end() && I->isBundledWithPred()) {
MI->setFlag(MachineInstr::BundledPred);
MI->setFlag(MachineInstr::BundledSucc);
}
return Insts.insert(I, MI);
}
MachineBasicBlock *MachineBasicBlock::removeFromParent() {
assert(getParent() && "Not embedded in a function!");
getParent()->remove(this);
return this;
}
void MachineBasicBlock::eraseFromParent() {
assert(getParent() && "Not embedded in a function!");
getParent()->erase(this);
}
void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
MachineBasicBlock *New) {
assert(Old != New && "Cannot replace self with self!");
MachineBasicBlock::instr_iterator I = instr_end();
while (I != instr_begin()) {
--I;
if (!I->isTerminator()) break;
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
if (I->getOperand(i).isMBB() &&
I->getOperand(i).getMBB() == Old)
I->getOperand(i).setMBB(New);
}
replaceSuccessor(Old, New);
}
bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
MachineBasicBlock *DestB,
bool isCond) {
bool Changed = false;
MachineFunction::iterator FallThru =
std::next(MachineFunction::iterator(this));
if (!DestA && !DestB) {
DestA = FallThru;
DestB = FallThru;
} else if (DestA && !DestB) {
if (isCond)
DestB = FallThru;
} else {
assert(DestA && DestB && isCond &&
"CFG in a bad state. Cannot correct CFG edges");
}
SmallPtrSet<const MachineBasicBlock*, 8> SeenMBBs;
MachineBasicBlock::succ_iterator SI = succ_begin();
while (SI != succ_end()) {
const MachineBasicBlock *MBB = *SI;
if (!SeenMBBs.insert(MBB).second ||
(MBB != DestA && MBB != DestB && !MBB->isLandingPad())) {
SI = removeSuccessor(SI);
Changed = true;
} else {
++SI;
}
}
return Changed;
}
DebugLoc
MachineBasicBlock::findDebugLoc(instr_iterator MBBI) {
DebugLoc DL;
instr_iterator E = instr_end();
if (MBBI == E)
return DL;
while (MBBI != E && MBBI->isDebugValue())
MBBI++;
if (MBBI != E)
DL = MBBI->getDebugLoc();
return DL;
}
uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const {
if (Weights.empty())
return 0;
return *getWeightIterator(Succ);
}
void MachineBasicBlock::setSuccWeight(succ_iterator I, uint32_t weight) {
if (Weights.empty())
return;
*getWeightIterator(I) = weight;
}
MachineBasicBlock::weight_iterator MachineBasicBlock::
getWeightIterator(MachineBasicBlock::succ_iterator I) {
assert(Weights.size() == Successors.size() && "Async weight list!");
size_t index = std::distance(Successors.begin(), I);
assert(index < Weights.size() && "Not a current successor!");
return Weights.begin() + index;
}
MachineBasicBlock::const_weight_iterator MachineBasicBlock::
getWeightIterator(MachineBasicBlock::const_succ_iterator I) const {
assert(Weights.size() == Successors.size() && "Async weight list!");
const size_t index = std::distance(Successors.begin(), I);
assert(index < Weights.size() && "Not a current successor!");
return Weights.begin() + index;
}
MachineBasicBlock::LivenessQueryResult
MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI,
unsigned Reg, MachineInstr *MI,
unsigned Neighborhood) {
unsigned N = Neighborhood;
MachineBasicBlock *MBB = MI->getParent();
MachineBasicBlock::iterator I(MI);
if (I != MBB->begin()) {
do {
--I;
MachineOperandIteratorBase::PhysRegInfo Analysis =
MIOperands(I).analyzePhysReg(Reg, TRI);
if (Analysis.Defines)
return Analysis.DefinesDead ? LQR_Dead : LQR_Live;
if (Analysis.Kills || Analysis.Clobbers)
return LQR_Dead;
else if (Analysis.ReadsOverlap)
return Analysis.Reads ? LQR_Live : LQR_OverlappingLive;
} while (I != MBB->begin() && --N > 0);
}
if (I == MBB->begin()) {
for (MCRegAliasIterator RAI(Reg, TRI, true);
RAI.isValid(); ++RAI) {
if (MBB->isLiveIn(*RAI))
return (*RAI == Reg) ? LQR_Live : LQR_OverlappingLive;
}
return LQR_Dead;
}
N = Neighborhood;
I = MachineBasicBlock::iterator(MI);
if (I != MBB->end()) {
for (++I; I != MBB->end() && N > 0; ++I, --N) {
MachineOperandIteratorBase::PhysRegInfo Analysis =
MIOperands(I).analyzePhysReg(Reg, TRI);
if (Analysis.ReadsOverlap)
return (Analysis.Reads) ?
LQR_Live : LQR_OverlappingLive;
else if (Analysis.Clobbers || Analysis.Defines)
return LQR_Dead;
}
}
return LQR_Unknown;
}