//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/BasicBlock.h"
+#include "llvm/CodeGen/LiveVariables.h"
+#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
+#include "llvm/CodeGen/SlotIndexes.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "Support/LeakDetector.h"
+#include "llvm/Assembly/Writer.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/LeakDetector.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
using namespace llvm;
+MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb)
+ : BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false),
+ AddressTaken(false) {
+ Insts.Parent = this;
+}
+
MachineBasicBlock::~MachineBasicBlock() {
LeakDetector::removeGarbageObject(this);
}
-
+/// getSymbol - Return the MCSymbol for this basic block.
+///
+MCSymbol *MachineBasicBlock::getSymbol() const {
+ const MachineFunction *MF = getParent();
+ MCContext &Ctx = MF->getContext();
+ const char *Prefix = Ctx.getAsmInfo().getPrivateGlobalPrefix();
+ return Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" +
+ Twine(MF->getFunctionNumber()) + "_" +
+ Twine(getNumber()));
+}
+
+
+raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineBasicBlock &MBB) {
+ MBB.print(OS);
+ return OS;
+}
+
+/// addNodeToList (MBB) - When an MBB is added to an MF, we need to update the
+/// parent pointer of the MBB, the MBB numbering, and any instructions in the
+/// MBB to be on the right operand list for registers.
+///
+/// MBBs start out as #-1. When a MBB is added to a MachineFunction, it
+/// gets the next available unique MBB number. If it is removed from a
+/// MachineFunction, it goes back to being #-1.
+void ilist_traits<MachineBasicBlock>::addNodeToList(MachineBasicBlock *N) {
+ MachineFunction &MF = *N->getParent();
+ N->Number = MF.addToMBBNumbering(N);
+
+ // Make sure the instructions have their operands in the reginfo lists.
+ MachineRegisterInfo &RegInfo = MF.getRegInfo();
+ for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I)
+ I->AddRegOperandsToUseLists(RegInfo);
-// MBBs start out as #-1. When a MBB is added to a MachineFunction, it
-// gets the next available unique MBB number. If it is removed from a
-// MachineFunction, it goes back to being #-1.
-void ilist_traits<MachineBasicBlock>::addNodeToList(MachineBasicBlock* N) {
- assert(N->Parent == 0 && "machine instruction already in a basic block");
- N->Parent = Parent;
- N->Number = Parent->addToMBBNumbering(N);
LeakDetector::removeGarbageObject(N);
}
-void ilist_traits<MachineBasicBlock>::removeNodeFromList(MachineBasicBlock* N) {
- assert(N->Parent != 0 && "machine instruction not in a basic block");
- N->Parent->removeFromMBBNumbering(N->Number);
+void ilist_traits<MachineBasicBlock>::removeNodeFromList(MachineBasicBlock *N) {
+ N->getParent()->removeFromMBBNumbering(N->Number);
N->Number = -1;
- N->Parent = 0;
LeakDetector::addGarbageObject(N);
}
-MachineInstr* ilist_traits<MachineInstr>::createNode() {
- MachineInstr* dummy = new MachineInstr(0, 0);
- LeakDetector::removeGarbageObject(dummy);
- return dummy;
+/// addNodeToList (MI) - When we add an instruction to a basic block
+/// list, we update its parent pointer and add its operands from reg use/def
+/// lists if appropriate.
+void ilist_traits<MachineInstr>::addNodeToList(MachineInstr *N) {
+ assert(N->getParent() == 0 && "machine instruction already in a basic block");
+ N->setParent(Parent);
+
+ // Add the instruction's register operands to their corresponding
+ // use/def lists.
+ MachineFunction *MF = Parent->getParent();
+ N->AddRegOperandsToUseLists(MF->getRegInfo());
+
+ LeakDetector::removeGarbageObject(N);
+}
+
+/// removeNodeFromList (MI) - When we remove an instruction from a basic block
+/// list, we update its parent pointer and remove its operands from reg use/def
+/// lists if appropriate.
+void ilist_traits<MachineInstr>::removeNodeFromList(MachineInstr *N) {
+ assert(N->getParent() != 0 && "machine instruction not in a basic block");
+
+ // Remove from the use/def lists.
+ N->RemoveRegOperandsFromUseLists();
+
+ N->setParent(0);
+
+ LeakDetector::addGarbageObject(N);
+}
+
+/// transferNodesFromList (MI) - When moving a range of instructions from one
+/// MBB list to another, we need to update the parent pointers and the use/def
+/// lists.
+void ilist_traits<MachineInstr>::
+transferNodesFromList(ilist_traits<MachineInstr> &fromList,
+ MachineBasicBlock::iterator first,
+ MachineBasicBlock::iterator last) {
+ assert(Parent->getParent() == fromList.Parent->getParent() &&
+ "MachineInstr parent mismatch!");
+
+ // Splice within the same MBB -> no change.
+ if (Parent == fromList.Parent) return;
+
+ // If splicing between two blocks within the same function, just update the
+ // parent pointers.
+ for (; first != last; ++first)
+ first->setParent(Parent);
}
-void ilist_traits<MachineInstr>::addNodeToList(MachineInstr* N)
-{
- assert(N->parent == 0 && "machine instruction already in a basic block");
- N->parent = parent;
- LeakDetector::removeGarbageObject(N);
+void ilist_traits<MachineInstr>::deleteNode(MachineInstr* MI) {
+ assert(!MI->getParent() && "MI is still in a block!");
+ Parent->getParent()->DeleteMachineInstr(MI);
}
-void ilist_traits<MachineInstr>::removeNodeFromList(MachineInstr* N)
-{
- assert(N->parent != 0 && "machine instruction not in a basic block");
- N->parent = 0;
- LeakDetector::addGarbageObject(N);
+MachineBasicBlock::iterator MachineBasicBlock::getFirstNonPHI() {
+ iterator I = begin();
+ while (I != end() && I->isPHI())
+ ++I;
+ return I;
}
-void ilist_traits<MachineInstr>::transferNodesFromList(
- iplist<MachineInstr, ilist_traits<MachineInstr> >& toList,
- ilist_iterator<MachineInstr> first,
- ilist_iterator<MachineInstr> last)
-{
- if (parent != toList.parent)
- for (; first != last; ++first)
- first->parent = toList.parent;
+MachineBasicBlock::iterator
+MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) {
+ while (I != end() && (I->isPHI() || I->isLabel() || I->isDebugValue()))
+ ++I;
+ return I;
}
-MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator()
-{
- const TargetInstrInfo& TII = *getParent()->getTarget().getInstrInfo();
+MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
iterator I = end();
- while (I != begin() && TII.isTerminatorInstr((--I)->getOpcode()));
- if (I != end() && !TII.isTerminatorInstr(I->getOpcode())) ++I;
+ while (I != begin() && ((--I)->getDesc().isTerminator() || I->isDebugValue()))
+ ; /*noop */
+ while (I != end() && !I->getDesc().isTerminator())
+ ++I;
return I;
}
-void MachineBasicBlock::dump() const
-{
- print(std::cerr);
+MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
+ iterator B = begin(), I = end();
+ while (I != B) {
+ --I;
+ if (I->isDebugValue())
+ continue;
+ return I;
+ }
+ // The block is all debug values.
+ return end();
+}
+
+const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const {
+ // A block with a landing pad successor only has one other successor.
+ if (succ_size() > 2)
+ return 0;
+ for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I)
+ if ((*I)->isLandingPad())
+ return *I;
+ return 0;
}
-void MachineBasicBlock::print(std::ostream &OS) const
-{
- if(!getParent()) {
- OS << "Can't print out MachineBasicBlock because parent MachineFunction is null\n";
+void MachineBasicBlock::dump() const {
+ print(dbgs());
+}
+
+StringRef MachineBasicBlock::getName() const {
+ if (const BasicBlock *LBB = getBasicBlock())
+ return LBB->getName();
+ else
+ return "(null)";
+}
+
+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 BasicBlock *LBB = getBasicBlock();
- if(LBB)
- OS << "\n" << LBB->getName() << " (" << (const void*)this
- << ", LLVM BB @" << (const void*) LBB << "):\n";
- for (const_iterator I = begin(); I != end(); ++I) {
- OS << "\t";
- I->print(OS, &getParent()->getTarget());
+
+ if (Alignment) { OS << "Alignment " << Alignment << "\n"; }
+
+ if (Indexes)
+ OS << Indexes->getMBBStartIdx(this) << '\t';
+
+ OS << "BB#" << getNumber() << ": ";
+
+ const char *Comma = "";
+ if (const BasicBlock *LBB = getBasicBlock()) {
+ OS << Comma << "derived from LLVM BB ";
+ WriteAsOperand(OS, LBB, /*PrintType=*/false);
+ Comma = ", ";
+ }
+ if (isLandingPad()) { OS << Comma << "EH LANDING PAD"; Comma = ", "; }
+ if (hasAddressTaken()) { OS << Comma << "ADDRESS TAKEN"; Comma = ", "; }
+ OS << '\n';
+
+ const TargetRegisterInfo *TRI = MF->getTarget().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';
+ }
+ // Print the preds of this block according to the CFG.
+ 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_iterator I = begin(); I != end(); ++I) {
+ if (Indexes) {
+ if (Indexes->hasIndex(I))
+ OS << Indexes->getInstructionIndex(I);
+ OS << '\t';
}
+ OS << '\t';
+ I->print(OS, &getParent()->getTarget());
+ }
+
+ // Print the successors of this block according to the CFG.
+ 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();
+ OS << '\n';
+ }
}
+
+void MachineBasicBlock::removeLiveIn(unsigned Reg) {
+ std::vector<unsigned>::iterator I =
+ std::find(LiveIns.begin(), LiveIns.end(), Reg);
+ assert(I != LiveIns.end() && "Not a live in!");
+ LiveIns.erase(I);
+}
+
+bool MachineBasicBlock::isLiveIn(unsigned Reg) const {
+ livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
+ return I != livein_end();
+}
+
+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()->getTarget().getInstrInfo();
+ // A block with no successors has no concerns with fall-through edges.
+ if (this->succ_empty()) return;
+
+ MachineBasicBlock *TBB = 0, *FBB = 0;
+ SmallVector<MachineOperand, 4> Cond;
+ DebugLoc dl; // FIXME: this is nowhere
+ bool B = TII->AnalyzeBranch(*this, TBB, FBB, Cond);
+ (void) B;
+ assert(!B && "UpdateTerminators requires analyzable predecessors!");
+ if (Cond.empty()) {
+ if (TBB) {
+ // The block has an unconditional branch. If its successor is now
+ // its layout successor, delete the branch.
+ if (isLayoutSuccessor(TBB))
+ TII->RemoveBranch(*this);
+ } else {
+ // The block has an unconditional fallthrough. If its successor is not
+ // its layout successor, insert a branch.
+ TBB = *succ_begin();
+ if (!isLayoutSuccessor(TBB))
+ TII->InsertBranch(*this, TBB, 0, Cond, dl);
+ }
+ } else {
+ if (FBB) {
+ // The block has a non-fallthrough conditional branch. If one of its
+ // successors is its layout successor, rewrite it to a fallthrough
+ // conditional branch.
+ if (isLayoutSuccessor(TBB)) {
+ if (TII->ReverseBranchCondition(Cond))
+ return;
+ TII->RemoveBranch(*this);
+ TII->InsertBranch(*this, FBB, 0, Cond, dl);
+ } else if (isLayoutSuccessor(FBB)) {
+ TII->RemoveBranch(*this);
+ TII->InsertBranch(*this, TBB, 0, Cond, dl);
+ }
+ } else {
+ // The block has a fallthrough conditional branch.
+ MachineBasicBlock *MBBA = *succ_begin();
+ MachineBasicBlock *MBBB = *llvm::next(succ_begin());
+ if (MBBA == TBB) std::swap(MBBB, MBBA);
+ if (isLayoutSuccessor(TBB)) {
+ if (TII->ReverseBranchCondition(Cond)) {
+ // We can't reverse the condition, add an unconditional branch.
+ Cond.clear();
+ TII->InsertBranch(*this, MBBA, 0, Cond, dl);
+ return;
+ }
+ TII->RemoveBranch(*this);
+ TII->InsertBranch(*this, MBBA, 0, Cond, dl);
+ } else if (!isLayoutSuccessor(MBBA)) {
+ TII->RemoveBranch(*this);
+ TII->InsertBranch(*this, TBB, MBBA, Cond, dl);
+ }
+ }
+ }
+}
+
+void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ, uint32_t weight) {
+
+ // If we see non-zero value for the first time it means we actually use Weight
+ // list, so we fill all Weights with 0's.
+ 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 Weight list is empty it means we don't use it (disabled optimization).
+ 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 Weight list is empty it means we don't use it (disabled optimization).
+ 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) {
+ uint32_t weight = 0;
+ succ_iterator SI = std::find(Successors.begin(), Successors.end(), Old);
+
+ // If Weight list is empty it means we don't use it (disabled optimization).
+ if (!Weights.empty()) {
+ weight_iterator WI = getWeightIterator(SI);
+ weight = *WI;
+ }
+
+ // Update the successor information.
+ removeSuccessor(SI);
+ addSuccessor(New, weight);
+}
+
+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 Weight list is empty it means we don't use it (disabled optimization).
+ 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();
+ addSuccessor(Succ);
+ fromMBB->removeSuccessor(Succ);
+
+ // Fix up any PHI nodes in the successor.
+ for (MachineBasicBlock::iterator MI = Succ->begin(), ME = Succ->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::isSuccessor(const MachineBasicBlock *MBB) const {
+ const_succ_iterator I = std::find(Successors.begin(), Successors.end(), MBB);
+ return I != Successors.end();
+}
+
+bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
+ MachineFunction::const_iterator I(this);
+ return llvm::next(I) == MachineFunction::const_iterator(MBB);
+}
+
+bool MachineBasicBlock::canFallThrough() {
+ MachineFunction::iterator Fallthrough = this;
+ ++Fallthrough;
+ // If FallthroughBlock is off the end of the function, it can't fall through.
+ if (Fallthrough == getParent()->end())
+ return false;
+
+ // If FallthroughBlock isn't a successor, no fallthrough is possible.
+ if (!isSuccessor(Fallthrough))
+ return false;
+
+ // Analyze the branches, if any, at the end of the block.
+ MachineBasicBlock *TBB = 0, *FBB = 0;
+ SmallVector<MachineOperand, 4> Cond;
+ const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo();
+ if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) {
+ // If we couldn't analyze the branch, examine the last instruction.
+ // If the block doesn't end in a known control barrier, assume fallthrough
+ // is possible. The isPredicable check is needed because this code can be
+ // called during IfConversion, where an instruction which is normally a
+ // Barrier is predicated and thus no longer an actual control barrier. This
+ // is over-conservative though, because if an instruction isn't actually
+ // predicated we could still treat it like a barrier.
+ return empty() || !back().getDesc().isBarrier() ||
+ back().getDesc().isPredicable();
+ }
+
+ // If there is no branch, control always falls through.
+ if (TBB == 0) return true;
+
+ // If there is some explicit branch to the fallthrough block, it can obviously
+ // reach, even though the branch should get folded to fall through implicitly.
+ if (MachineFunction::iterator(TBB) == Fallthrough ||
+ MachineFunction::iterator(FBB) == Fallthrough)
+ return true;
+
+ // If it's an unconditional branch to some block not the fall through, it
+ // doesn't fall through.
+ if (Cond.empty()) return false;
+
+ // Otherwise, if it is conditional and has no explicit false block, it falls
+ // through.
+ return FBB == 0;
+}
+
+MachineBasicBlock *
+MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) {
+ MachineFunction *MF = getParent();
+ DebugLoc dl; // FIXME: this is nowhere
+
+ // We may need to update this's terminator, but we can't do that if
+ // AnalyzeBranch fails. If this uses a jump table, we won't touch it.
+ const TargetInstrInfo *TII = MF->getTarget().getInstrInfo();
+ MachineBasicBlock *TBB = 0, *FBB = 0;
+ SmallVector<MachineOperand, 4> Cond;
+ if (TII->AnalyzeBranch(*this, TBB, FBB, Cond))
+ return NULL;
+
+ // Avoid bugpoint weirdness: A block may end with a conditional branch but
+ // jumps to the same MBB is either case. We have duplicate CFG edges in that
+ // case that we can't handle. Since this never happens in properly optimized
+ // code, just skip those edges.
+ if (TBB && TBB == FBB) {
+ DEBUG(dbgs() << "Won't split critical edge after degenerate BB#"
+ << getNumber() << '\n');
+ return NULL;
+ }
+
+ MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock();
+ MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB);
+ DEBUG(dbgs() << "Splitting critical edge:"
+ " BB#" << getNumber()
+ << " -- BB#" << NMBB->getNumber()
+ << " -- BB#" << Succ->getNumber() << '\n');
+
+ // On some targets like Mips, branches may kill virtual registers. Make sure
+ // that LiveVariables is properly updated after updateTerminator replaces the
+ // terminators.
+ LiveVariables *LV = P->getAnalysisIfAvailable<LiveVariables>();
+
+ // Collect a list of virtual registers killed by the terminators.
+ SmallVector<unsigned, 4> KilledRegs;
+ if (LV)
+ for (iterator I = getFirstTerminator(), E = 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->isUse() || !OI->isKill() || OI->isUndef())
+ continue;
+ unsigned Reg = OI->getReg();
+ if (TargetRegisterInfo::isVirtualRegister(Reg) &&
+ LV->getVarInfo(Reg).removeKill(MI)) {
+ KilledRegs.push_back(Reg);
+ DEBUG(dbgs() << "Removing terminator kill: " << *MI);
+ OI->setIsKill(false);
+ }
+ }
+ }
+
+ ReplaceUsesOfBlockWith(Succ, NMBB);
+ updateTerminator();
+
+ // Insert unconditional "jump Succ" instruction in NMBB if necessary.
+ NMBB->addSuccessor(Succ);
+ if (!NMBB->isLayoutSuccessor(Succ)) {
+ Cond.clear();
+ MF->getTarget().getInstrInfo()->InsertBranch(*NMBB, Succ, NULL, Cond, dl);
+ }
+
+ // Fix PHI nodes in Succ so they refer to NMBB instead of this
+ for (MachineBasicBlock::iterator i = Succ->begin(), e = Succ->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);
+
+ // Inherit live-ins from the successor
+ for (MachineBasicBlock::livein_iterator I = Succ->livein_begin(),
+ E = Succ->livein_end(); I != E; ++I)
+ NMBB->addLiveIn(*I);
+
+ // Update LiveVariables.
+ if (LV) {
+ // Restore kills of virtual registers that were killed by the terminators.
+ while (!KilledRegs.empty()) {
+ unsigned Reg = KilledRegs.pop_back_val();
+ for (iterator I = end(), E = begin(); I != E;) {
+ if (!(--I)->addRegisterKilled(Reg, NULL, /* addIfNotFound= */ false))
+ continue;
+ LV->getVarInfo(Reg).Kills.push_back(I);
+ DEBUG(dbgs() << "Restored terminator kill: " << *I);
+ break;
+ }
+ }
+ // Update relevant live-through information.
+ LV->addNewBlock(NMBB, this, Succ);
+ }
+
+ if (MachineDominatorTree *MDT =
+ P->getAnalysisIfAvailable<MachineDominatorTree>()) {
+ // Update dominator information.
+ MachineDomTreeNode *SucccDTNode = MDT->getNode(Succ);
+
+ bool IsNewIDom = true;
+ for (const_pred_iterator PI = Succ->pred_begin(), E = Succ->pred_end();
+ PI != E; ++PI) {
+ MachineBasicBlock *PredBB = *PI;
+ if (PredBB == NMBB)
+ continue;
+ if (!MDT->dominates(SucccDTNode, MDT->getNode(PredBB))) {
+ IsNewIDom = false;
+ break;
+ }
+ }
+
+ // We know "this" dominates the newly created basic block.
+ MachineDomTreeNode *NewDTNode = MDT->addNewBlock(NMBB, this);
+
+ // If all the other predecessors of "Succ" are dominated by "Succ" itself
+ // then the new block is the new immediate dominator of "Succ". Otherwise,
+ // the new block doesn't dominate anything.
+ if (IsNewIDom)
+ MDT->changeImmediateDominator(SucccDTNode, NewDTNode);
+ }
+
+ if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable<MachineLoopInfo>())
+ if (MachineLoop *TIL = MLI->getLoopFor(this)) {
+ // If one or the other blocks were not in a loop, the new block is not
+ // either, and thus LI doesn't need to be updated.
+ if (MachineLoop *DestLoop = MLI->getLoopFor(Succ)) {
+ if (TIL == DestLoop) {
+ // Both in the same loop, the NMBB joins loop.
+ DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
+ } else if (TIL->contains(DestLoop)) {
+ // Edge from an outer loop to an inner loop. Add to the outer loop.
+ TIL->addBasicBlockToLoop(NMBB, MLI->getBase());
+ } else if (DestLoop->contains(TIL)) {
+ // Edge from an inner loop to an outer loop. Add to the outer loop.
+ DestLoop->addBasicBlockToLoop(NMBB, MLI->getBase());
+ } else {
+ // Edge from two loops with no containment relation. Because these
+ // are natural loops, we know that the destination block must be the
+ // header of its loop (adding a branch into a loop elsewhere would
+ // create an irreducible loop).
+ assert(DestLoop->getHeader() == Succ &&
+ "Should not create irreducible loops!");
+ if (MachineLoop *P = DestLoop->getParentLoop())
+ P->addBasicBlockToLoop(NMBB, MLI->getBase());
+ }
+ }
+ }
+
+ return NMBB;
+}
+
+/// removeFromParent - This method unlinks 'this' from the containing function,
+/// and returns it, but does not delete it.
+MachineBasicBlock *MachineBasicBlock::removeFromParent() {
+ assert(getParent() && "Not embedded in a function!");
+ getParent()->remove(this);
+ return this;
+}
+
+
+/// eraseFromParent - This method unlinks 'this' from the containing function,
+/// and deletes it.
+void MachineBasicBlock::eraseFromParent() {
+ assert(getParent() && "Not embedded in a function!");
+ getParent()->erase(this);
+}
+
+
+/// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
+/// 'Old', change the code and CFG so that it branches to 'New' instead.
+void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old,
+ MachineBasicBlock *New) {
+ assert(Old != New && "Cannot replace self with self!");
+
+ MachineBasicBlock::iterator I = end();
+ while (I != begin()) {
+ --I;
+ if (!I->getDesc().isTerminator()) break;
+
+ // Scan the operands of this machine instruction, replacing any uses of Old
+ // with New.
+ 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);
+ }
+
+ // Update the successor information.
+ replaceSuccessor(Old, New);
+}
+
+/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in the
+/// CFG to be inserted. If we have proven that MBB can only branch to DestA and
+/// DestB, remove any other MBB successors from the CFG. DestA and DestB can be
+/// null.
+///
+/// Besides DestA and DestB, retain other edges leading to LandingPads
+/// (currently there can be only one; we don't check or require that here).
+/// Note it is possible that DestA and/or DestB are LandingPads.
+bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA,
+ MachineBasicBlock *DestB,
+ bool isCond) {
+ // The values of DestA and DestB frequently come from a call to the
+ // 'TargetInstrInfo::AnalyzeBranch' method. We take our meaning of the initial
+ // values from there.
+ //
+ // 1. If both DestA and DestB are null, then the block ends with no branches
+ // (it falls through to its successor).
+ // 2. If DestA is set, DestB is null, and isCond is false, then the block ends
+ // with only an unconditional branch.
+ // 3. If DestA is set, DestB is null, and isCond is true, then the block ends
+ // with a conditional branch that falls through to a successor (DestB).
+ // 4. If DestA and DestB is set and isCond is true, then the block ends with a
+ // conditional branch followed by an unconditional branch. DestA is the
+ // 'true' destination and DestB is the 'false' destination.
+
+ bool Changed = false;
+
+ MachineFunction::iterator FallThru =
+ llvm::next(MachineFunction::iterator(this));
+
+ if (DestA == 0 && DestB == 0) {
+ // Block falls through to successor.
+ DestA = FallThru;
+ DestB = FallThru;
+ } else if (DestA != 0 && DestB == 0) {
+ if (isCond)
+ // Block ends in conditional jump that falls through to successor.
+ DestB = FallThru;
+ } else {
+ assert(DestA && DestB && isCond &&
+ "CFG in a bad state. Cannot correct CFG edges");
+ }
+
+ // Remove superfluous edges. I.e., those which aren't destinations of this
+ // basic block, duplicate edges, or landing pads.
+ SmallPtrSet<const MachineBasicBlock*, 8> SeenMBBs;
+ MachineBasicBlock::succ_iterator SI = succ_begin();
+ while (SI != succ_end()) {
+ const MachineBasicBlock *MBB = *SI;
+ if (!SeenMBBs.insert(MBB) ||
+ (MBB != DestA && MBB != DestB && !MBB->isLandingPad())) {
+ // This is a superfluous edge, remove it.
+ SI = removeSuccessor(SI);
+ Changed = true;
+ } else {
+ ++SI;
+ }
+ }
+
+ return Changed;
+}
+
+/// findDebugLoc - find the next valid DebugLoc starting at MBBI, skipping
+/// any DBG_VALUE instructions. Return UnknownLoc if there is none.
+DebugLoc
+MachineBasicBlock::findDebugLoc(MachineBasicBlock::iterator &MBBI) {
+ DebugLoc DL;
+ MachineBasicBlock::iterator E = end();
+ if (MBBI != E) {
+ // Skip debug declarations, we don't want a DebugLoc from them.
+ MachineBasicBlock::iterator MBBI2 = MBBI;
+ while (MBBI2 != E && MBBI2->isDebugValue())
+ MBBI2++;
+ if (MBBI2 != E)
+ DL = MBBI2->getDebugLoc();
+ }
+ return DL;
+}
+
+/// getSuccWeight - Return weight of the edge from this block to MBB.
+///
+uint32_t MachineBasicBlock::getSuccWeight(MachineBasicBlock *succ) {
+ if (Weights.empty())
+ return 0;
+
+ succ_iterator I = std::find(Successors.begin(), Successors.end(), succ);
+ return *getWeightIterator(I);
+}
+
+/// getWeightIterator - Return wight iterator corresonding to the I successor
+/// iterator
+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;
+}
+
+void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
+ bool t) {
+ OS << "BB#" << MBB->getNumber();
+}
+
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