X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=lib%2FCodeGen%2FMachineBasicBlock.cpp;h=9ff4858f0a4e0a574a1acdf93d07af81c54d5801;hp=bc1998c3bf15fb0939d99d5ba99dc5671498dd4f;hb=e11e167a1f2d84d86a38e2e25d2446ad1b707576;hpb=12af5ff7205630a802fe4b4ca355fa143c1449f1 diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index bc1998c3bf1..9ff4858f0a4 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -12,47 +12,53 @@ //===----------------------------------------------------------------------===// #include "llvm/CodeGen/MachineBasicBlock.h" -#include "llvm/BasicBlock.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/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 "llvm/Target/TargetInstrInfo.h" +#include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetRegisterInfo.h" +#include "llvm/Target/TargetSubtargetInfo.h" #include 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) { + AddressTaken(false), CachedMCSymbol(nullptr) { Insts.Parent = this; } MachineBasicBlock::~MachineBasicBlock() { - LeakDetector::removeGarbageObject(this); } -/// getSymbol - Return the MCSymbol for this basic block. -/// +/// 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())); + 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; } @@ -61,9 +67,9 @@ raw_ostream &llvm::operator<<(raw_ostream &OS, const MachineBasicBlock &MBB) { 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. +/// 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 @@ -74,55 +80,46 @@ void ilist_traits::addNodeToList(MachineBasicBlock *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) + for (MachineBasicBlock::instr_iterator + I = N->instr_begin(), E = N->instr_end(); I != E; ++I) I->AddRegOperandsToUseLists(RegInfo); - - LeakDetector::removeGarbageObject(N); } void ilist_traits::removeNodeFromList(MachineBasicBlock *N) { N->getParent()->removeFromMBBNumbering(N->Number); N->Number = -1; - LeakDetector::addGarbageObject(N); } - -/// 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. +/// 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::addNodeToList(MachineInstr *N) { - assert(N->getParent() == 0 && "machine instruction already in a basic block"); + assert(!N->getParent() && "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. +/// 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::removeNodeFromList(MachineInstr *N) { - assert(N->getParent() != 0 && "machine instruction not in a basic block"); + assert(N->getParent() && "machine instruction not in a basic block"); // Remove from the use/def lists. - N->RemoveRegOperandsFromUseLists(); + if (MachineFunction *MF = N->getParent()->getParent()) + N->RemoveRegOperandsFromUseLists(MF->getRegInfo()); - N->setParent(0); - - LeakDetector::addGarbageObject(N); + N->setParent(nullptr); } -/// 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. +/// 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:: transferNodesFromList(ilist_traits &fromList, - MachineBasicBlock::iterator first, - MachineBasicBlock::iterator last) { + ilist_iterator first, + ilist_iterator last) { assert(Parent->getParent() == fromList.Parent->getParent() && "MachineInstr parent mismatch!"); @@ -141,33 +138,59 @@ void ilist_traits::deleteNode(MachineInstr* MI) { } MachineBasicBlock::iterator MachineBasicBlock::getFirstNonPHI() { - iterator I = begin(); - while (I != end() && I->isPHI()) + 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) { - while (I != end() && (I->isPHI() || I->isLabel() || I->isDebugValue())) + iterator E = end(); + while (I != E && (I->isPHI() || I->isPosition() || I->isDebugValue())) ++I; + // FIXME: This needs to change if we wish to bundle labels / dbg_values + // inside the bundle. + assert((I == E || !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() || I->isDebugValue())) + iterator B = begin(), E = end(), I = E; + while (I != B && ((--I)->isTerminator() || I->isDebugValue())) ; /*noop */ - while (I != end() && !I->getDesc().isTerminator()) + 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::getFirstNonDebugInstr() { + // Skip over begin-of-block dbg_value instructions. + iterator I = begin(), E = end(); + while (I != E && I->isDebugValue()) ++I; return I; } MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() { - iterator B = begin(), I = end(); + // Skip over end-of-block dbg_value instructions. + instr_iterator B = instr_begin(), I = instr_end(); while (I != B) { --I; - if (I->isDebugValue()) + // Return instruction that starts a bundle. + if (I->isDebugValue() || I->isInsideBundle()) continue; return I; } @@ -178,16 +201,18 @@ MachineBasicBlock::iterator MachineBasicBlock::getLastNonDebugInstr() { const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const { // A block with a landing pad successor only has one other successor. if (succ_size() > 2) - return 0; + return nullptr; for (const_succ_iterator I = succ_begin(), E = succ_end(); I != E; ++I) if ((*I)->isLandingPad()) return *I; - return 0; + 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()) @@ -196,6 +221,18 @@ StringRef MachineBasicBlock::getName() const { return "(null)"; } +/// Return a hopefully unique identifier for this block. +std::string MachineBasicBlock::getFullName() const { + std::string Name; + if (getParent()) + Name = (getParent()->getName() + ":").str(); + if (getBasicBlock()) + Name += getBasicBlock()->getName(); + else + Name += ("BB" + Twine(getNumber())).str(); + return Name; +} + void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const { const MachineFunction *MF = getParent(); if (!MF) { @@ -203,8 +240,20 @@ void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const { << " is null\n"; return; } + const Function *F = MF->getFunction(); + const Module *M = F ? F->getParent() : nullptr; + ModuleSlotTracker MST(M); + print(OS, MST, Indexes); +} - if (Alignment) { OS << "Alignment " << Alignment << "\n"; } +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'; @@ -214,19 +263,24 @@ void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const { const char *Comma = ""; if (const BasicBlock *LBB = getBasicBlock()) { OS << Comma << "derived from LLVM BB "; - WriteAsOperand(OS, LBB, /*PrintType=*/false); + LBB->printAsOperand(OS, /*PrintType=*/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->getTarget().getRegisterInfo(); + 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); + for (unsigned LI : make_range(livein_begin(), livein_end())) { + OS << ' ' << PrintReg(LI, TRI); + } OS << '\n'; } // Print the preds of this block according to the CFG. @@ -238,31 +292,41 @@ void MachineBasicBlock::print(raw_ostream &OS, SlotIndexes *Indexes) const { 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'; - I->print(OS, &getParent()->getTarget()); + if (I->isInsideBundle()) + OS << " * "; + I->print(OS, MST); } // 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) + 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 /*PrintType*/) const { + OS << "BB#" << getNumber(); +} + void MachineBasicBlock::removeLiveIn(unsigned Reg) { - std::vector::iterator I = - std::find(LiveIns.begin(), LiveIns.end(), Reg); - assert(I != LiveIns.end() && "Not a live in!"); - LiveIns.erase(I); + std::vector::iterator I + = std::find(LiveIns.begin(), LiveIns.end(), Reg); + if (I != LiveIns.end()) + LiveIns.erase(I); } bool MachineBasicBlock::isLiveIn(unsigned Reg) const { @@ -270,6 +334,38 @@ bool MachineBasicBlock::isLiveIn(unsigned Reg) const { 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(); + + // Look for an existing copy. + 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; + } + + // No luck, create a virtual register. + 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); } @@ -280,11 +376,11 @@ void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) { } void MachineBasicBlock::updateTerminator() { - const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo(); + const TargetInstrInfo *TII = getParent()->getSubtarget().getInstrInfo(); // A block with no successors has no concerns with fall-through edges. if (this->succ_empty()) return; - MachineBasicBlock *TBB = 0, *FBB = 0; + MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; DebugLoc dl; // FIXME: this is nowhere bool B = TII->AnalyzeBranch(*this, TBB, FBB, Cond); @@ -298,10 +394,24 @@ void MachineBasicBlock::updateTerminator() { TII->RemoveBranch(*this); } else { // The block has an unconditional fallthrough. If its successor is not - // its layout successor, insert a branch. - TBB = *succ_begin(); + // 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); + TII->InsertBranch(*this, TBB, nullptr, Cond, dl); } } else { if (FBB) { @@ -312,34 +422,65 @@ void MachineBasicBlock::updateTerminator() { if (TII->ReverseBranchCondition(Cond)) return; TII->RemoveBranch(*this); - TII->InsertBranch(*this, FBB, 0, Cond, dl); + TII->InsertBranch(*this, FBB, nullptr, Cond, dl); } else if (isLayoutSuccessor(FBB)) { TII->RemoveBranch(*this); - TII->InsertBranch(*this, TBB, 0, Cond, dl); + TII->InsertBranch(*this, TBB, nullptr, 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 = 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()) { + // 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, nullptr, Cond, dl); + return; + } + // 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); + TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl); return; } TII->RemoveBranch(*this); - TII->InsertBranch(*this, MBBA, 0, Cond, dl); - } else if (!isLayoutSuccessor(MBBA)) { + TII->InsertBranch(*this, FallthroughBB, nullptr, Cond, dl); + } else if (!isLayoutSuccessor(FallthroughBB)) { TII->RemoveBranch(*this); - TII->InsertBranch(*this, TBB, MBBA, Cond, dl); + TII->InsertBranch(*this, TBB, FallthroughBB, Cond, dl); } } } } -void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) { +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); } @@ -348,16 +489,70 @@ 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) { + 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 New isn't already a successor, let it take Old's place. + if (NewI == E) { + New->addPredecessor(this); + *OldI = New; + return; + } + + // New is already a successor. + // Update its weight instead of adding a duplicate edge. + 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); } @@ -374,7 +569,13 @@ void MachineBasicBlock::transferSuccessors(MachineBasicBlock *fromMBB) { while (!fromMBB->succ_empty()) { MachineBasicBlock *Succ = *fromMBB->succ_begin(); - addSuccessor(Succ); + 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); } } @@ -386,12 +587,15 @@ MachineBasicBlock::transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB) { while (!fromMBB->succ_empty()) { MachineBasicBlock *Succ = *fromMBB->succ_begin(); - addSuccessor(Succ); + uint32_t Weight = 0; + if (!fromMBB->Weights.empty()) + Weight = *fromMBB->Weights.begin(); + addSuccessor(Succ, Weight); 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 (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) @@ -400,14 +604,17 @@ MachineBasicBlock::transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB) { } } +bool MachineBasicBlock::isPredecessor(const MachineBasicBlock *MBB) const { + return std::find(pred_begin(), pred_end(), MBB) != pred_end(); +} + bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const { - const_succ_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 llvm::next(I) == MachineFunction::const_iterator(MBB); + return std::next(I) == MachineFunction::const_iterator(MBB); } bool MachineBasicBlock::canFallThrough() { @@ -422,23 +629,20 @@ bool MachineBasicBlock::canFallThrough() { return false; // Analyze the branches, if any, at the end of the block. - MachineBasicBlock *TBB = 0, *FBB = 0; + MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; - const TargetInstrInfo *TII = getParent()->getTarget().getInstrInfo(); + const TargetInstrInfo *TII = getParent()->getSubtarget().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 + // 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. 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(); + // 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 (!TBB) 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. @@ -452,21 +656,31 @@ bool MachineBasicBlock::canFallThrough() { // Otherwise, if it is conditional and has no explicit false block, it falls // through. - return FBB == 0; + return FBB == nullptr; } 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 nullptr; + MachineFunction *MF = getParent(); DebugLoc dl; // FIXME: this is nowhere + // Performance might be harmed on HW that implements branching using exec mask + // where both sides of the branches are always executed. + if (MF->getTarget().requiresStructuredCFG()) + return nullptr; + // 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; + const TargetInstrInfo *TII = MF->getSubtarget().getInstrInfo(); + MachineBasicBlock *TBB = nullptr, *FBB = nullptr; SmallVector Cond; if (TII->AnalyzeBranch(*this, TBB, FBB, Cond)) - return NULL; + return nullptr; // 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 @@ -475,16 +689,23 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { if (TBB && TBB == FBB) { DEBUG(dbgs() << "Won't split critical edge after degenerate BB#" << getNumber() << '\n'); - return NULL; + return nullptr; } MachineBasicBlock *NMBB = MF->CreateMachineBasicBlock(); - MF->insert(llvm::next(MachineFunction::iterator(this)), NMBB); + 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(); + SlotIndexes *Indexes = P->getAnalysisIfAvailable(); + if (LIS) + LIS->insertMBBInMaps(NMBB); + else if (Indexes) + Indexes->insertMBBInMaps(NMBB); + // On some targets like Mips, branches may kill virtual registers. Make sure // that LiveVariables is properly updated after updateTerminator replaces the // terminators. @@ -493,14 +714,16 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { // Collect a list of virtual registers killed by the terminators. SmallVector KilledRegs; if (LV) - for (iterator I = getFirstTerminator(), E = end(); I != E; ++I) { + 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->isUse() || !OI->isKill() || OI->isUndef()) + if (!OI->isReg() || OI->getReg() == 0 || + !OI->isUse() || !OI->isKill() || OI->isUndef()) continue; unsigned Reg = OI->getReg(); - if (TargetRegisterInfo::isVirtualRegister(Reg) && + if (TargetRegisterInfo::isPhysicalRegister(Reg) || LV->getVarInfo(Reg).removeKill(MI)) { KilledRegs.push_back(Reg); DEBUG(dbgs() << "Removing terminator kill: " << *MI); @@ -509,32 +732,93 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { } } + SmallVector 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); + + // If updateTerminator() removes instructions, we need to remove them from + // SlotIndexes. + SmallVector Terminators; + if (Indexes) { + for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); + I != E; ++I) + Terminators.push_back(I); + } + updateTerminator(); + if (Indexes) { + SmallVector NewTerminators; + for (instr_iterator I = getFirstInstrTerminator(), E = instr_end(); + I != E; ++I) + NewTerminators.push_back(I); + + for (SmallVectorImpl::iterator I = Terminators.begin(), + E = Terminators.end(); I != E; ++I) { + if (std::find(NewTerminators.begin(), NewTerminators.end(), *I) == + NewTerminators.end()) + Indexes->removeMachineInstrFromMaps(*I); + } + } + // 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); + 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) { + // Some instructions may have been moved to NMBB by updateTerminator(), + // so we first remove any instruction that already has an index. + if (Indexes->hasIndex(I)) + Indexes->removeMachineInstrFromMaps(I); + Indexes->insertMachineInstrInMaps(I); + } + } } // Fix PHI nodes in Succ so they refer to NMBB instead of this - for (MachineBasicBlock::iterator i = Succ->begin(), e = Succ->end(); + 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 (unsigned LI : Succ->liveins()) + NMBB->addLiveIn(LI); + // Update LiveVariables. + const TargetRegisterInfo *TRI = MF->getSubtarget().getRegisterInfo(); 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)) + for (instr_iterator I = instr_end(), E = instr_begin(); I != E;) { + if (!(--I)->addRegisterKilled(Reg, TRI, /* addIfNotFound= */ false)) continue; - LV->getVarInfo(Reg).Kills.push_back(I); + if (TargetRegisterInfo::isVirtualRegister(Reg)) + LV->getVarInfo(Reg).Kills.push_back(I); DEBUG(dbgs() << "Restored terminator kill: " << *I); break; } @@ -543,33 +827,72 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { LV->addNewBlock(NMBB, this, Succ); } - if (MachineDominatorTree *MDT = - P->getAnalysisIfAvailable()) { - // 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; + if (LIS) { + // After splitting the edge and updating SlotIndexes, live intervals may be + // in one of two situations, depending on whether this block was the last in + // the function. If the original block was the last in the function, all + // live intervals will end prior to the beginning of the new split block. If + // the original block was not at the end of the function, all live intervals + // will extend to the end of the new split block. + + bool isLastMBB = + std::next(MachineFunction::iterator(NMBB)) == getParent()->end(); + + SlotIndex StartIndex = Indexes->getMBBEndIdx(this); + SlotIndex PrevIndex = StartIndex.getPrevSlot(); + SlotIndex EndIndex = Indexes->getMBBEndIdx(NMBB); + + // Find the registers used from NMBB in PHIs in Succ. + SmallSet 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)); + } } } - // We know "this" dominates the newly created basic block. - MachineDomTreeNode *NewDTNode = MDT->addNewBlock(NMBB, this); + 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); + } + } - // 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); + // Update all intervals for registers whose uses may have been modified by + // updateTerminator(). + LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs); } + if (MachineDominatorTree *MDT = + P->getAnalysisIfAvailable()) + MDT->recordSplitCriticalEdge(this, Succ, NMBB); + if (MachineLoopInfo *MLI = P->getAnalysisIfAvailable()) if (MachineLoop *TIL = MLI->getLoopFor(this)) { // If one or the other blocks were not in a loop, the new block is not @@ -600,33 +923,68 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { return NMBB; } -/// removeFromParent - This method unlinks 'this' from the containing function, -/// and returns it, but does not delete it. +/// Prepare MI to be removed from its bundle. This fixes bundle flags on MI's +/// neighboring instructions so the bundle won't be broken by removing MI. +static void unbundleSingleMI(MachineInstr *MI) { + // Removing the first instruction in a bundle. + if (MI->isBundledWithSucc() && !MI->isBundledWithPred()) + MI->unbundleFromSucc(); + // Removing the last instruction in a bundle. + if (MI->isBundledWithPred() && !MI->isBundledWithSucc()) + MI->unbundleFromPred(); + // If MI is not bundled, or if it is internal to a bundle, the neighbor flags + // are already fine. +} + +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"); + // Set the bundle flags when inserting inside a bundle. + if (I != instr_end() && I->isBundledWithPred()) { + MI->setFlag(MachineInstr::BundledPred); + MI->setFlag(MachineInstr::BundledSucc); + } + return Insts.insert(I, MI); +} + +/// 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. +/// 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. +/// 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()) { + 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. @@ -637,14 +995,12 @@ void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old, } // 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. +/// 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). @@ -669,13 +1025,13 @@ bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA, bool Changed = false; MachineFunction::iterator FallThru = - llvm::next(MachineFunction::iterator(this)); + std::next(MachineFunction::iterator(this)); - if (DestA == 0 && DestB == 0) { + if (!DestA && !DestB) { // Block falls through to successor. DestA = FallThru; DestB = FallThru; - } else if (DestA != 0 && DestB == 0) { + } else if (DestA && !DestB) { if (isCond) // Block ends in conditional jump that falls through to successor. DestB = FallThru; @@ -690,7 +1046,7 @@ bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA, MachineBasicBlock::succ_iterator SI = succ_begin(); while (SI != succ_end()) { const MachineBasicBlock *MBB = *SI; - if (!SeenMBBs.insert(MBB) || + if (!SeenMBBs.insert(MBB).second || (MBB != DestA && MBB != DestB && !MBB->isLandingPad())) { // This is a superfluous edge, remove it. SI = removeSuccessor(SI); @@ -703,25 +1059,127 @@ bool MachineBasicBlock::CorrectExtraCFGEdges(MachineBasicBlock *DestA, return Changed; } -/// findDebugLoc - find the next valid DebugLoc starting at MBBI, skipping -/// any DBG_VALUE instructions. Return UnknownLoc if there is none. +/// 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) { +MachineBasicBlock::findDebugLoc(instr_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(); - } + 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; } -void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB, - bool t) { - OS << "BB#" << MBB->getNumber(); +/// Return weight of the edge from this block to MBB. +uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const { + if (Weights.empty()) + return 0; + + return *getWeightIterator(Succ); } +/// Set successor weight of a given iterator. +void MachineBasicBlock::setSuccWeight(succ_iterator I, uint32_t weight) { + if (Weights.empty()) + return; + *getWeightIterator(I) = weight; +} + +/// 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; +} + +/// 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; +} + +/// Return whether (physical) register "Reg" has been ined and not ed +/// as of just before "MI". +/// +/// Search is localised to a neighborhood of +/// Neighborhood instructions before (searching for defs or kills) and N +/// instructions after (searching just for defs) MI. +MachineBasicBlock::LivenessQueryResult +MachineBasicBlock::computeRegisterLiveness(const TargetRegisterInfo *TRI, + unsigned Reg, const_iterator Before, + unsigned Neighborhood) const { + unsigned N = Neighborhood; + + // Start by searching backwards from Before, looking for kills, reads or defs. + const_iterator I(Before); + // If this is the first insn in the block, don't search backwards. + if (I != begin()) { + do { + --I; + + MachineOperandIteratorBase::PhysRegInfo Analysis = + ConstMIOperands(I).analyzePhysReg(Reg, TRI); + + if (Analysis.Defines) + // Outputs happen after inputs so they take precedence if both are + // present. + return Analysis.DefinesDead ? LQR_Dead : LQR_Live; + + if (Analysis.Kills || Analysis.Clobbers) + // Register killed, so isn't live. + return LQR_Dead; + + else if (Analysis.ReadsOverlap) + // Defined or read without a previous kill - live. + return Analysis.Reads ? LQR_Live : LQR_OverlappingLive; + + } while (I != begin() && --N > 0); + } + + // Did we get to the start of the block? + if (I == begin()) { + // If so, the register's state is definitely defined by the live-in state. + for (MCRegAliasIterator RAI(Reg, TRI, /*IncludeSelf=*/true); + RAI.isValid(); ++RAI) { + if (isLiveIn(*RAI)) + return (*RAI == Reg) ? LQR_Live : LQR_OverlappingLive; + } + + return LQR_Dead; + } + + N = Neighborhood; + + // Try searching forwards from Before, looking for reads or defs. + I = const_iterator(Before); + // If this is the last insn in the block, don't search forwards. + if (I != end()) { + for (++I; I != end() && N > 0; ++I, --N) { + MachineOperandIteratorBase::PhysRegInfo Analysis = + ConstMIOperands(I).analyzePhysReg(Reg, TRI); + + if (Analysis.ReadsOverlap) + // Used, therefore must have been live. + return (Analysis.Reads) ? + LQR_Live : LQR_OverlappingLive; + + else if (Analysis.Clobbers || Analysis.Defines) + // Defined (but not read) therefore cannot have been live. + return LQR_Dead; + } + } + + // At this point we have no idea of the liveness of the register. + return LQR_Unknown; +}