#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/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/TargetInstrDesc.h"
+#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.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) {
+ : BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false),
+ AddressTaken(false) {
Insts.Parent = this;
}
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
+/// 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.
///
// 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)
+ for (MachineBasicBlock::instr_iterator
+ I = N->instr_begin(), E = N->instr_end(); I != E; ++I)
I->AddRegOperandsToUseLists(RegInfo);
LeakDetector::removeGarbageObject(N);
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();
// Remove from the use/def lists.
N->RemoveRegOperandsFromUseLists();
-
+
N->setParent(0);
LeakDetector::addGarbageObject(N);
/// lists.
void ilist_traits<MachineInstr>::
transferNodesFromList(ilist_traits<MachineInstr> &fromList,
- MachineBasicBlock::iterator first,
- MachineBasicBlock::iterator last) {
+ ilist_iterator<MachineInstr> first,
+ ilist_iterator<MachineInstr> last) {
assert(Parent->getParent() == fromList.Parent->getParent() &&
"MachineInstr parent mismatch!");
Parent->getParent()->DeleteMachineInstr(MI);
}
+MachineBasicBlock::iterator MachineBasicBlock::getFirstNonPHI() {
+ instr_iterator I = instr_begin(), E = instr_end();
+ while (I != E && I->isPHI())
+ ++I;
+ assert(!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->isLabel() || I->isDebugValue()))
+ ++I;
+ // FIXME: This needs to change if we wish to bundle labels / dbg_values
+ // inside the bundle.
+ assert(!I->isInsideBundle() &&
+ "First non-phi / non-label instruction is inside a bundle!");
+ return I;
+}
+
MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
- iterator I = end();
- while (I != begin() && (--I)->getDesc().isTerminator())
+ iterator B = begin(), E = end(), I = E;
+ while (I != B && ((--I)->isTerminator() || I->isDebugValue()))
; /*noop */
- if (I != end() && !I->getDesc().isTerminator()) ++I;
+ while (I != E && !I->isTerminator())
+ ++I;
return I;
}
-/// isOnlyReachableViaFallthough - Return true if this basic block has
-/// exactly one predecessor and the control transfer mechanism between
-/// the predecessor and this block is a fall-through.
-bool MachineBasicBlock::isOnlyReachableByFallthrough() const {
- // If this is a landing pad, it isn't a fall through. If it has no preds,
- // then nothing falls through to it.
- if (isLandingPad() || pred_empty())
- return false;
-
- // If there isn't exactly one predecessor, it can't be a fall through.
- const_pred_iterator PI = pred_begin(), PI2 = PI;
- ++PI2;
- if (PI2 != pred_end())
- return false;
-
- // The predecessor has to be immediately before this block.
- const MachineBasicBlock *Pred = *PI;
-
- if (!Pred->isLayoutSuccessor(this))
- return false;
-
- // If the block is completely empty, then it definitely does fall through.
- if (Pred->empty())
- return true;
-
- // Otherwise, check the last instruction.
- const MachineInstr &LastInst = Pred->back();
- return !LastInst.getDesc().isBarrier();
+MachineBasicBlock::const_iterator
+MachineBasicBlock::getFirstTerminator() const {
+ const_iterator B = begin(), E = end(), I = E;
+ while (I != B && ((--I)->isTerminator() || I->isDebugValue()))
+ ; /*noop */
+ 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()))
+ ; /*noop */
+ while (I != E && !I->isTerminator())
+ ++I;
+ return I;
+}
+
+MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() {
+ // Skip over end-of-block dbg_value instructions.
+ instr_iterator B = instr_begin(), I = instr_end();
+ while (I != B) {
+ --I;
+ // Return instruction that starts a bundle.
+ if (I->isDebugValue() || I->isInsideBundle())
+ continue;
+ return I;
+ }
+ // The block is all debug values.
+ return end();
+}
+
+MachineBasicBlock::const_iterator
+MachineBasicBlock::getLastNonDebugInstr() const {
+ // Skip over end-of-block dbg_value instructions.
+ const_instr_iterator B = instr_begin(), I = instr_end();
+ while (I != B) {
+ --I;
+ // Return instruction that starts a bundle.
+ if (I->isDebugValue() || I->isInsideBundle())
+ 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::dump() const {
- print(errs());
+ print(dbgs());
}
-static inline void OutputReg(raw_ostream &os, unsigned RegNo,
- const TargetRegisterInfo *TRI = 0) {
- if (!RegNo || TargetRegisterInfo::isPhysicalRegister(RegNo)) {
- if (TRI)
- os << " %" << TRI->get(RegNo).Name;
- else
- os << " %mreg(" << RegNo << ")";
- } else
- os << " %reg" << RegNo;
+StringRef MachineBasicBlock::getName() const {
+ if (const BasicBlock *LBB = getBasicBlock())
+ return LBB->getName();
+ else
+ return "(null)";
}
-void MachineBasicBlock::print(raw_ostream &OS) const {
+/// Return a hopefully unique identifier for this block.
+std::string MachineBasicBlock::getFullName() const {
+ std::string Name;
+ if (getParent())
+ Name = (getParent()->getFunction()->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"
return;
}
- const BasicBlock *LBB = getBasicBlock();
+ 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 = ", "; }
+ if (Alignment)
+ OS << Comma << "Align " << Alignment << " (" << (1u << Alignment)
+ << " bytes)";
+
OS << '\n';
- if (LBB) OS << LBB->getName() << ": ";
- OS << (const void*)this
- << ", LLVM BB @" << (const void*) LBB << ", ID#" << getNumber();
- if (Alignment) OS << ", Alignment " << Alignment;
- if (isLandingPad()) OS << ", EH LANDING PAD";
- OS << ":\n";
-
- const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
+
+ const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
if (!livein_empty()) {
- OS << "Live Ins:";
- for (const_livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I)
- OutputReg(OS, *I, TRI);
+ 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 << ' ' << *PI << " (#" << (*PI)->getNumber() << ')';
+ OS << " BB#" << (*PI)->getNumber();
OS << '\n';
}
-
- for (const_iterator I = begin(); I != end(); ++I) {
+
+ 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, &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 << ' ' << *SI << " (#" << (*SI)->getNumber() << ')';
+ OS << " BB#" << (*SI)->getNumber();
OS << '\n';
}
}
void MachineBasicBlock::removeLiveIn(unsigned Reg) {
- livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
- assert(I != livein_end() && "Not a live in!");
- LiveIns.erase(I);
+ 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 {
- const_livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
+ livein_iterator I = std::find(livein_begin(), livein_end(), Reg);
return I != livein_end();
}
getParent()->splice(++BBI, this);
}
-
-void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) {
- Successors.push_back(succ);
- succ->addPredecessor(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. First we have to locate the
+ // only non-landing-pad successor, as that is the fallthrough block.
+ 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 there is no non-landing-pad successor, the block has no
+ // fall-through edges to be concerned with.
+ if (!TBB)
+ return;
+
+ // Finally update the unconditional successor to be reached via a branch
+ // if it would not be reached by fallthrough.
+ 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 {
+ // Walk through the successors and find the successor which is not
+ // a landing pad and is not the conditional branch destination (in TBB)
+ // as the fallthrough successor.
+ MachineBasicBlock *FallthroughBB = 0;
+ 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()) {
+ // We fallthrough to the same basic block as the conditional jump
+ // targets. Remove the conditional jump, leaving unconditional
+ // fallthrough.
+ // FIXME: This does not seem like a reasonable pattern to support, but it
+ // has been seen in the wild coming out of degenerate ARM test cases.
+ TII->RemoveBranch(*this);
+
+ // Finally update the unconditional successor to be reached via a branch
+ // if it would not be reached by fallthrough.
+ if (!isLayoutSuccessor(TBB))
+ TII->InsertBranch(*this, TBB, 0, Cond, dl);
+ return;
+ }
+
+ // The block has a fallthrough conditional branch.
+ if (isLayoutSuccessor(TBB)) {
+ if (TII->ReverseBranchCondition(Cond)) {
+ // We can't reverse the condition, add an unconditional branch.
+ Cond.clear();
+ TII->InsertBranch(*this, FallthroughBB, 0, Cond, dl);
+ return;
+ }
+ TII->RemoveBranch(*this);
+ TII->InsertBranch(*this, FallthroughBB, 0, 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 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::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) {
- std::vector<MachineBasicBlock *>::iterator I =
- std::find(Predecessors.begin(), Predecessors.end(), 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;
-
- for (MachineBasicBlock::succ_iterator I = fromMBB->succ_begin(),
- E = fromMBB->succ_end(); I != E; ++I)
- addSuccessor(*I);
-
- while (!fromMBB->succ_empty())
- fromMBB->removeSuccessor(fromMBB->succ_begin());
+
+ 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::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 {
- std::vector<MachineBasicBlock *>::const_iterator I =
- std::find(Successors.begin(), Successors.end(), MBB);
- return I != Successors.end();
+ return std::find(succ_begin(), succ_end(), MBB) != succ_end();
}
bool MachineBasicBlock::isLayoutSuccessor(const MachineBasicBlock *MBB) const {
MachineFunction::const_iterator I(this);
- return next(I) == MachineFunction::const_iterator(MBB);
+ 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 isPredicated 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.
+ return empty() || !back().isBarrier() || TII->isPredicated(&back());
+ }
+
+ // 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) {
+ // Splitting the critical edge to a landing pad block is non-trivial. Don't do
+ // it in this generic function.
+ if (Succ->isLandingPad())
+ return NULL;
+
+ 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 (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);
+ }
+ }
+ }
+
+ 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::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);
+
+ // 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.
+ const TargetRegisterInfo *TRI = MF->getTarget().getRegisterInfo();
+ if (LV) {
+ // Restore kills of virtual registers that were killed by the terminators.
+ 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, /* addIfNotFound= */ false))
+ continue;
+ if (TargetRegisterInfo::isVirtualRegister(Reg))
+ 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;
+}
+
+MachineBasicBlock::iterator
+MachineBasicBlock::erase(MachineBasicBlock::iterator I) {
+ if (I->isBundle()) {
+ MachineBasicBlock::iterator E = llvm::next(I);
+ return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
+ }
+
+ return Insts.erase(I.getInstrIterator());
+}
+
+MachineInstr *MachineBasicBlock::remove(MachineInstr *I) {
+ if (I->isBundle()) {
+ instr_iterator MII = llvm::next(I);
+ iterator E = end();
+ while (MII != E && MII->isInsideBundle()) {
+ MachineInstr *MI = &*MII++;
+ Insts.remove(MI);
+ }
+ }
+
+ return Insts.remove(I);
+}
+
+void MachineBasicBlock::splice(MachineBasicBlock::iterator where,
+ MachineBasicBlock *Other,
+ MachineBasicBlock::iterator From) {
+ if (From->isBundle()) {
+ MachineBasicBlock::iterator To = llvm::next(From);
+ Insts.splice(where.getInstrIterator(), Other->Insts,
+ From.getInstrIterator(), To.getInstrIterator());
+ return;
+ }
+
+ Insts.splice(where.getInstrIterator(), Other->Insts, From.getInstrIterator());
}
/// removeFromParent - This method unlinks 'this' from the containing function,
MachineBasicBlock *New) {
assert(Old != New && "Cannot replace self with self!");
- MachineBasicBlock::iterator I = end();
- while (I != begin()) {
+ MachineBasicBlock::instr_iterator I = instr_end();
+ while (I != instr_begin()) {
--I;
- if (!I->getDesc().isTerminator()) break;
+ if (!I->isTerminator()) break;
// Scan the operands of this machine instruction, replacing any uses of Old
// with New.
}
// Update the successor information.
- removeSuccessor(Old);
- addSuccessor(New);
+ 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.
+/// 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) {
- bool MadeChange = false;
- bool AddedFallThrough = false;
-
- MachineFunction::iterator FallThru = next(MachineFunction::iterator(this));
-
- // If this block ends with a conditional branch that falls through to its
- // successor, set DestB as the successor.
- if (isCond) {
- if (DestB == 0 && FallThru != getParent()->end()) {
+ // 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;
- AddedFallThrough = true;
- }
} else {
- // If this is an unconditional branch with no explicit dest, it must just be
- // a fallthrough into DestB.
- if (DestA == 0 && FallThru != getParent()->end()) {
- DestA = FallThru;
- AddedFallThrough = true;
- }
+ 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();
- MachineBasicBlock *OrigDestA = DestA, *OrigDestB = DestB;
while (SI != succ_end()) {
- if (*SI == DestA && DestA == DestB) {
- DestA = DestB = 0;
- ++SI;
- } else if (*SI == DestA) {
- DestA = 0;
- ++SI;
- } else if (*SI == DestB) {
- DestB = 0;
- ++SI;
- } else if ((*SI)->isLandingPad() &&
- *SI!=OrigDestA && *SI!=OrigDestB) {
- ++SI;
- } else {
- // Otherwise, this is a superfluous edge, remove it.
+ const MachineBasicBlock *MBB = *SI;
+ if (!SeenMBBs.insert(MBB) ||
+ (MBB != DestA && MBB != DestB && !MBB->isLandingPad())) {
+ // This is a superfluous edge, remove it.
SI = removeSuccessor(SI);
- MadeChange = true;
+ Changed = true;
+ } else {
+ ++SI;
}
}
- if (!AddedFallThrough) {
- assert(DestA == 0 && DestB == 0 &&
- "MachineCFG is missing edges!");
- } else if (isCond) {
- assert(DestA == 0 && "MachineCFG is missing edges!");
- }
- return MadeChange;
+
+ 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(instr_iterator MBBI) {
+ DebugLoc DL;
+ instr_iterator E = instr_end();
+ if (MBBI == E)
+ return DL;
+
+ // Skip debug declarations, we don't want a DebugLoc from them.
+ while (MBBI != E && MBBI->isDebugValue())
+ MBBI++;
+ if (MBBI != E)
+ DL = MBBI->getDebugLoc();
+ return DL;
+}
+
+/// getSuccWeight - Return weight of the edge from this block to MBB.
+///
+uint32_t MachineBasicBlock::getSuccWeight(const MachineBasicBlock *succ) const {
+ if (Weights.empty())
+ return 0;
+
+ const_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;
+}
+
+/// getWeightIterator - Return wight iterator corresonding to the I successor
+/// iterator
+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;
+}
+
+void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB,
+ bool t) {
+ OS << "BB#" << MBB->getNumber();
+}
+
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