X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineBasicBlock.cpp;h=eaaa1f85b563996e0978e502a9950f88d2296877;hb=fdb42fa5fe794cc2c89e2ed7f57a89ed24d9952a;hp=5ca18d086acc2aa16f4a27c0fb1486d97e598a56;hpb=74ab84c31ef64538a1b56e1f282e49303412ad17;p=oota-llvm.git diff --git a/lib/CodeGen/MachineBasicBlock.cpp b/lib/CodeGen/MachineBasicBlock.cpp index 5ca18d086ac..eaaa1f85b56 100644 --- a/lib/CodeGen/MachineBasicBlock.cpp +++ b/lib/CodeGen/MachineBasicBlock.cpp @@ -14,19 +14,45 @@ #include "llvm/CodeGen/MachineBasicBlock.h" #include "llvm/BasicBlock.h" #include "llvm/CodeGen/MachineFunction.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 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); } -std::ostream& llvm::operator<<(std::ostream &OS, const MachineBasicBlock &MBB) { +/// 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; } @@ -38,96 +64,76 @@ std::ostream& llvm::operator<<(std::ostream &OS, const MachineBasicBlock &MBB) { /// 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::addNodeToList(MachineBasicBlock* N) { - assert(N->getParent() == 0 && "machine instruction already in a basic block"); - N->setParent(Parent); - N->Number = Parent->addToMBBNumbering(N); +void ilist_traits::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 = Parent->getRegInfo(); + MachineRegisterInfo &RegInfo = MF.getRegInfo(); for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I) I->AddRegOperandsToUseLists(RegInfo); - + LeakDetector::removeGarbageObject(N); } -void ilist_traits::removeNodeFromList(MachineBasicBlock* N) { - assert(N->getParent() != 0 && "machine instruction not in a basic block"); +void ilist_traits::removeNodeFromList(MachineBasicBlock *N) { N->getParent()->removeFromMBBNumbering(N->Number); N->Number = -1; - N->setParent(0); - - // Make sure the instructions have their operands removed from the reginfo - // lists. - for (MachineBasicBlock::iterator I = N->begin(), E = N->end(); I != E; ++I) - I->RemoveRegOperandsFromUseLists(); - LeakDetector::addGarbageObject(N); } -MachineInstr* ilist_traits::createSentinel() { - MachineInstr* dummy = new MachineInstr(); - 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::addNodeToList(MachineInstr* N) { +void ilist_traits::addNodeToList(MachineInstr *N) { assert(N->getParent() == 0 && "machine instruction already in a basic block"); - N->setParent(parent); - LeakDetector::removeGarbageObject(N); + N->setParent(Parent); - // If the block is in a function, add the instruction's register operands to - // their corresponding use/def lists. - if (MachineFunction *MF = parent->getParent()) - N->AddRegOperandsToUseLists(MF->getRegInfo()); + // 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::removeNodeFromList(MachineInstr* N) { +void ilist_traits::removeNodeFromList(MachineInstr *N) { assert(N->getParent() != 0 && "machine instruction not in a basic block"); - // If this block is in a function, remove from the use/def lists. - if (parent->getParent() != 0) - N->RemoveRegOperandsFromUseLists(); + + // 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::transferNodesFromList( - iplist >& fromList, - ilist_iterator first, - ilist_iterator last) { +void ilist_traits:: +transferNodesFromList(ilist_traits &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 (Parent == fromList.Parent) return; // If splicing between two blocks within the same function, just update the // parent pointers. - if (parent->getParent() == fromList.parent->getParent()) { - for (; first != last; ++first) - first->setParent(parent); - return; - } - - // Otherwise, we have to update the parent and the use/def lists. The common - // case when this occurs is if we're splicing from a block in a MF to a block - // that is not in an MF. - bool HasOldMF = fromList.parent->getParent() != 0; - MachineFunction *NewMF = parent->getParent(); - - for (; first != last; ++first) { - if (HasOldMF) first->RemoveRegOperandsFromUseLists(); - first->setParent(parent); - if (NewMF) first->AddRegOperandsToUseLists(NewMF->getRegInfo()); - } + for (; first != last; ++first) + first->setParent(Parent); +} + +void ilist_traits::deleteNode(MachineInstr* MI) { + assert(!MI->getParent() && "MI is still in a block!"); + Parent->getParent()->DeleteMachineInstr(MI); } MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() { @@ -139,53 +145,66 @@ MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() { } void MachineBasicBlock::dump() const { - print(*cerr.stream()); + print(dbgs()); } -static inline void OutputReg(std::ostream &os, unsigned RegNo, +static inline void OutputReg(raw_ostream &os, unsigned RegNo, const TargetRegisterInfo *TRI = 0) { - if (!RegNo || TargetRegisterInfo::isPhysicalRegister(RegNo)) { + if (RegNo != 0 && TargetRegisterInfo::isPhysicalRegister(RegNo)) { if (TRI) - os << " %" << TRI->get(RegNo).PrintableName; + os << " %" << TRI->get(RegNo).Name; else - os << " %mreg(" << RegNo << ")"; + os << " %physreg" << RegNo; } else os << " %reg" << RegNo; } -void MachineBasicBlock::print(std::ostream &OS) const { +StringRef MachineBasicBlock::getName() const { + if (const BasicBlock *LBB = getBasicBlock()) + return LBB->getName(); + else + return "(null)"; +} + +void MachineBasicBlock::print(raw_ostream &OS) const { const MachineFunction *MF = getParent(); - if(!MF) { + if (!MF) { OS << "Can't print out MachineBasicBlock because parent MachineFunction" << " is null\n"; return; } - const BasicBlock *LBB = getBasicBlock(); - OS << "\n"; - if (LBB) OS << LBB->getName() << ": "; - OS << (const void*)this - << ", LLVM BB @" << (const void*) LBB << ", ID#" << getNumber(); - if (isLandingPad()) OS << ", EH LANDING PAD"; - OS << ":\n"; + if (Alignment) { OS << "Alignment " << Alignment << "\n"; } + + 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()) { - OS << "Live Ins:"; - for (const_livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I) + OS << " Live Ins:"; + for (livein_iterator I = livein_begin(),E = livein_end(); I != E; ++I) OutputReg(OS, *I, TRI); - OS << "\n"; + OS << '\n'; } // Print the preds of this block according to the CFG. if (!pred_empty()) { OS << " Predecessors according to CFG:"; for (const_pred_iterator PI = pred_begin(), E = pred_end(); PI != E; ++PI) - OS << " " << *PI << " (#" << (*PI)->getNumber() << ")"; - OS << "\n"; + OS << " BB#" << (*PI)->getNumber(); + OS << '\n'; } for (const_iterator I = begin(); I != end(); ++I) { - OS << "\t"; + OS << '\t'; I->print(OS, &getParent()->getTarget()); } @@ -193,28 +212,90 @@ void MachineBasicBlock::print(std::ostream &OS) const { if (!succ_empty()) { OS << " Successors according to CFG:"; for (const_succ_iterator SI = succ_begin(), E = succ_end(); SI != E; ++SI) - OS << " " << *SI << " (#" << (*SI)->getNumber() << ")"; - OS << "\n"; + 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!"); + std::vector::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) { - MachineFunction::BasicBlockListType &BBList =getParent()->getBasicBlockList(); - getParent()->getBasicBlockList().splice(NewAfter, BBList, this); + getParent()->splice(NewAfter, this); } void MachineBasicBlock::moveAfter(MachineBasicBlock *NewBefore) { - MachineFunction::BasicBlockListType &BBList =getParent()->getBasicBlockList(); MachineFunction::iterator BBI = NewBefore; - getParent()->getBasicBlockList().splice(++BBI, BBList, this); + 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 Cond; + 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); + } + } 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); + } else if (isLayoutSuccessor(FBB)) { + TII->RemoveBranch(*this); + TII->InsertBranch(*this, TBB, 0, Cond); + } + } 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); + return; + } + TII->RemoveBranch(*this); + TII->InsertBranch(*this, MBBA, 0, Cond); + } else if (!isLayoutSuccessor(MBBA)) { + TII->RemoveBranch(*this); + TII->InsertBranch(*this, TBB, MBBA, Cond); + } + } + } +} void MachineBasicBlock::addSuccessor(MachineBasicBlock *succ) { Successors.push_back(succ); @@ -232,7 +313,7 @@ MachineBasicBlock::succ_iterator MachineBasicBlock::removeSuccessor(succ_iterator I) { assert(I != Successors.end() && "Not a current successor!"); (*I)->removePredecessor(this); - return(Successors.erase(I)); + return Successors.erase(I); } void MachineBasicBlock::addPredecessor(MachineBasicBlock *pred) { @@ -246,12 +327,91 @@ void MachineBasicBlock::removePredecessor(MachineBasicBlock *pred) { Predecessors.erase(I); } -bool MachineBasicBlock::isSuccessor(MachineBasicBlock *MBB) const { +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()); +} + +bool MachineBasicBlock::isSuccessor(const MachineBasicBlock *MBB) const { std::vector::const_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 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; +} + +/// 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, @@ -266,74 +426,97 @@ void MachineBasicBlock::ReplaceUsesOfBlockWith(MachineBasicBlock *Old, // 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) + if (I->getOperand(i).isMBB() && + I->getOperand(i).getMBB() == Old) I->getOperand(i).setMBB(New); } - // Update the successor information. If New was already a successor, just - // remove the link to Old instead of creating another one. PR 1444. + // Update the successor information. removeSuccessor(Old); - if (!isSuccessor(New)) - addSuccessor(New); + addSuccessor(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; - - MachineBasicBlock *FallThru = getNext(); - - // 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 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 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 MadeChange; + return DL; } + +void llvm::WriteAsOperand(raw_ostream &OS, const MachineBasicBlock *MBB, + bool t) { + OS << "BB#" << MBB->getNumber(); +} +