X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineBasicBlock.cpp;h=78e9950e5ef5604d10bedf93fdaaabd11feb3c72;hb=1db3d0820f8057dd03ade1585bfa5f2bf53cfe33;hp=fa6b4502c4ab746b9d98dae601b6ba13e8f9b083;hpb=03e593efc65807dad7ca8807554584fcb89f40f1;p=oota-llvm.git diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index fa6b4502c4a..78e9950e5ef 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -12,30 +12,32 @@ //===----------------------------------------------------------------------===// #include "llvm/CodeGen/MachineBasicBlock.h" -#include "llvm/BasicBlock.h" +#include "llvm/ADT/SmallPtrSet.h" +#include "llvm/ADT/SmallString.h" +#include "llvm/Assembly/Writer.h" +#include "llvm/CodeGen/LiveIntervalAnalysis.h" #include "llvm/CodeGen/LiveVariables.h" #include "llvm/CodeGen/MachineDominators.h" #include "llvm/CodeGen/MachineFunction.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/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 "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 using namespace llvm; MachineBasicBlock::MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb) : BB(bb), Number(-1), xParent(&mf), Alignment(0), IsLandingPad(false), - AddressTaken(false) { + AddressTaken(false), CachedMCSymbol(NULL) { Insts.Parent = this; } @@ -46,12 +48,16 @@ MachineBasicBlock::~MachineBasicBlock() { /// 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())); + if (!CachedMCSymbol) { + const MachineFunction *MF = getParent(); + MCContext &Ctx = MF->getContext(); + const char *Prefix = Ctx.getAsmInfo().getPrivateGlobalPrefix(); + CachedMCSymbol = Ctx.GetOrCreateSymbol(Twine(Prefix) + "BB" + + Twine(MF->getFunctionNumber()) + + "_" + Twine(getNumber())); + } + + return CachedMCSymbol; } @@ -145,7 +151,8 @@ 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!"); + assert((I == E || !I->isInsideBundle()) && + "First non-phi MI cannot be inside a bundle!"); return I; } @@ -156,7 +163,7 @@ MachineBasicBlock::SkipPHIsAndLabels(MachineBasicBlock::iterator I) { ++I; // FIXME: This needs to change if we wish to bundle labels / dbg_values // inside the bundle. - assert(!I->isInsideBundle() && + assert((I == E || !I->isInsideBundle()) && "First non-phi / non-label instruction is inside a bundle!"); return I; } @@ -228,9 +235,11 @@ const MachineBasicBlock *MachineBasicBlock::getLandingPadSuccessor() const { return 0; } +#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) void MachineBasicBlock::dump() const { print(dbgs()); } +#endif StringRef MachineBasicBlock::getName() const { if (const BasicBlock *LBB = getBasicBlock()) @@ -243,7 +252,7 @@ StringRef MachineBasicBlock::getName() const { std::string MachineBasicBlock::getFullName() const { std::string Name; if (getParent()) - Name = (getParent()->getFunction()->getName() + ":").str(); + Name = (getParent()->getName() + ":").str(); if (getBasicBlock()) Name += getBasicBlock()->getName(); else @@ -660,6 +669,13 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { << " -- 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. @@ -686,14 +702,67 @@ 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); + + 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 @@ -728,6 +797,67 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { LV->addNewBlock(NMBB, this, Succ); } + 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 = + llvm::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.addRange(LiveRange(StartIndex, EndIndex, VNI)); + } + } + } + + MachineRegisterInfo *MRI = &getParent()->getRegInfo(); + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { + unsigned Reg = TargetRegisterInfo::index2VirtReg(i); + if (PHISrcRegs.count(Reg) || !LIS->hasInterval(Reg)) + continue; + + LiveInterval &LI = LIS->getInterval(Reg); + if (!LI.liveAt(PrevIndex)) + continue; + + bool isLiveOut = LI.liveAt(LIS->getMBBStartIdx(Succ)); + if (isLiveOut && isLastMBB) { + VNInfo *VNI = LI.getVNInfoAt(PrevIndex); + assert(VNI && "LiveInterval should have VNInfo where it is live."); + LI.addRange(LiveRange(StartIndex, EndIndex, VNI)); + } else if (!isLiveOut && !isLastMBB) { + LI.removeRange(StartIndex, EndIndex); + } + } + + // Update all intervals for registers whose uses may have been modified by + // updateTerminator(). + LIS->repairIntervalsInRange(this, getFirstTerminator(), end(), UsedRegs); + } + if (MachineDominatorTree *MDT = P->getAnalysisIfAvailable()) { // Update dominator information. @@ -785,40 +915,42 @@ MachineBasicBlock::SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P) { 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()); +/// 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. } -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); - } - } +MachineBasicBlock::instr_iterator +MachineBasicBlock::erase(MachineBasicBlock::instr_iterator I) { + unbundleSingleMI(I); + return Insts.erase(I); +} - return Insts.remove(I); +MachineInstr *MachineBasicBlock::remove_instr(MachineInstr *MI) { + unbundleSingleMI(MI); + MI->clearFlag(MachineInstr::BundledPred); + MI->clearFlag(MachineInstr::BundledSucc); + return Insts.remove(MI); } -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; +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); } - - Insts.splice(where.getInstrIterator(), Other->Insts, From.getInstrIterator()); + return Insts.insert(I, MI); } /// removeFromParent - This method unlinks 'this' from the containing function, @@ -942,12 +1074,11 @@ MachineBasicBlock::findDebugLoc(instr_iterator MBBI) { /// getSuccWeight - Return weight of the edge from this block to MBB. /// -uint32_t MachineBasicBlock::getSuccWeight(const MachineBasicBlock *succ) const { +uint32_t MachineBasicBlock::getSuccWeight(const_succ_iterator Succ) const { if (Weights.empty()) return 0; - const_succ_iterator I = std::find(Successors.begin(), Successors.end(), succ); - return *getWeightIterator(I); + return *getWeightIterator(Succ); } /// getWeightIterator - Return wight iterator corresonding to the I successor @@ -970,6 +1101,83 @@ getWeightIterator(MachineBasicBlock::const_succ_iterator I) const { 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, MachineInstr *MI, + unsigned Neighborhood) { + unsigned N = Neighborhood; + MachineBasicBlock *MBB = MI->getParent(); + + // Start by searching backwards from MI, looking for kills, reads or defs. + + MachineBasicBlock::iterator I(MI); + // If this is the first insn in the block, don't search backwards. + if (I != MBB->begin()) { + do { + --I; + + MachineOperandIteratorBase::PhysRegInfo Analysis = + MIOperands(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 != MBB->begin() && --N > 0); + } + + // Did we get to the start of the block? + if (I == MBB->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 (MBB->isLiveIn(*RAI)) + return (*RAI == Reg) ? LQR_Live : LQR_OverlappingLive; + } + + return LQR_Dead; + } + + N = Neighborhood; + + // Try searching forwards from MI, looking for reads or defs. + I = MachineBasicBlock::iterator(MI); + // If this is the last insn in the block, don't search forwards. + if (I != MBB->end()) { + for (++I; I != MBB->end() && N > 0; ++I, --N) { + MachineOperandIteratorBase::PhysRegInfo Analysis = + MIOperands(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; +} + void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB, bool t) { OS << "BB#" << MBB->getNumber();