//===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // Collect the sequence of machine instructions for a basic block. // //===----------------------------------------------------------------------===// #ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H #define LLVM_CODEGEN_MACHINEBASICBLOCK_H #include "llvm/ADT/GraphTraits.h" #include "llvm/ADT/iterator_range.h" #include "llvm/CodeGen/MachineInstrBundleIterator.h" #include "llvm/CodeGen/MachineInstr.h" #include "llvm/Support/BranchProbability.h" #include "llvm/MC/LaneBitmask.h" #include "llvm/MC/MCRegisterInfo.h" #include "llvm/Support/DataTypes.h" #include namespace llvm { class Pass; class BasicBlock; class MachineFunction; class MCSymbol; class MIPrinter; class SlotIndexes; class StringRef; class raw_ostream; class MachineBranchProbabilityInfo; template <> struct ilist_traits { private: friend class MachineBasicBlock; // Set by the owning MachineBasicBlock. MachineBasicBlock *Parent; typedef simple_ilist>::iterator instr_iterator; public: void addNodeToList(MachineInstr *N); void removeNodeFromList(MachineInstr *N); void transferNodesFromList(ilist_traits &OldList, instr_iterator First, instr_iterator Last); void deleteNode(MachineInstr *MI); }; class MachineBasicBlock : public ilist_node_with_parent { public: /// Pair of physical register and lane mask. /// This is not simply a std::pair typedef because the members should be named /// clearly as they both have an integer type. struct RegisterMaskPair { public: MCPhysReg PhysReg; LaneBitmask LaneMask; RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask) : PhysReg(PhysReg), LaneMask(LaneMask) {} }; private: typedef ilist> Instructions; Instructions Insts; const BasicBlock *BB; int Number; MachineFunction *xParent; /// Keep track of the predecessor / successor basic blocks. std::vector Predecessors; std::vector Successors; /// Keep track of the probabilities to the successors. This vector has the /// same order as Successors, or it is empty if we don't use it (disable /// optimization). std::vector Probs; typedef std::vector::iterator probability_iterator; typedef std::vector::const_iterator const_probability_iterator; /// Keep track of the physical registers that are livein of the basicblock. typedef std::vector LiveInVector; LiveInVector LiveIns; /// Alignment of the basic block. Zero if the basic block does not need to be /// aligned. The alignment is specified as log2(bytes). unsigned Alignment = 0; /// Indicate that this basic block is entered via an exception handler. bool IsEHPad = false; /// Indicate that this basic block is potentially the target of an indirect /// branch. bool AddressTaken = false; /// Indicate that this basic block is the entry block of an EH funclet. bool IsEHFuncletEntry = false; /// Indicate that this basic block is the entry block of a cleanup funclet. bool IsCleanupFuncletEntry = false; /// \brief since getSymbol is a relatively heavy-weight operation, the symbol /// is only computed once and is cached. mutable MCSymbol *CachedMCSymbol = nullptr; // Intrusive list support MachineBasicBlock() {} explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB); ~MachineBasicBlock(); // MachineBasicBlocks are allocated and owned by MachineFunction. friend class MachineFunction; public: /// Return the LLVM basic block that this instance corresponded to originally. /// Note that this may be NULL if this instance does not correspond directly /// to an LLVM basic block. const BasicBlock *getBasicBlock() const { return BB; } /// Return the name of the corresponding LLVM basic block, or "(null)". StringRef getName() const; /// Return a formatted string to identify this block and its parent function. std::string getFullName() const; /// Test whether this block is potentially the target of an indirect branch. bool hasAddressTaken() const { return AddressTaken; } /// Set this block to reflect that it potentially is the target of an indirect /// branch. void setHasAddressTaken() { AddressTaken = true; } /// Return the MachineFunction containing this basic block. const MachineFunction *getParent() const { return xParent; } MachineFunction *getParent() { return xParent; } typedef Instructions::iterator instr_iterator; typedef Instructions::const_iterator const_instr_iterator; typedef Instructions::reverse_iterator reverse_instr_iterator; typedef Instructions::const_reverse_iterator const_reverse_instr_iterator; typedef MachineInstrBundleIterator iterator; typedef MachineInstrBundleIterator const_iterator; typedef MachineInstrBundleIterator reverse_iterator; typedef MachineInstrBundleIterator const_reverse_iterator; unsigned size() const { return (unsigned)Insts.size(); } bool empty() const { return Insts.empty(); } MachineInstr &instr_front() { return Insts.front(); } MachineInstr &instr_back() { return Insts.back(); } const MachineInstr &instr_front() const { return Insts.front(); } const MachineInstr &instr_back() const { return Insts.back(); } MachineInstr &front() { return Insts.front(); } MachineInstr &back() { return *--end(); } const MachineInstr &front() const { return Insts.front(); } const MachineInstr &back() const { return *--end(); } instr_iterator instr_begin() { return Insts.begin(); } const_instr_iterator instr_begin() const { return Insts.begin(); } instr_iterator instr_end() { return Insts.end(); } const_instr_iterator instr_end() const { return Insts.end(); } reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); } const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); } reverse_instr_iterator instr_rend () { return Insts.rend(); } const_reverse_instr_iterator instr_rend () const { return Insts.rend(); } typedef iterator_range instr_range; typedef iterator_range const_instr_range; instr_range instrs() { return instr_range(instr_begin(), instr_end()); } const_instr_range instrs() const { return const_instr_range(instr_begin(), instr_end()); } iterator begin() { return instr_begin(); } const_iterator begin() const { return instr_begin(); } iterator end () { return instr_end(); } const_iterator end () const { return instr_end(); } reverse_iterator rbegin() { return reverse_iterator::getAtBundleBegin(instr_rbegin()); } const_reverse_iterator rbegin() const { return const_reverse_iterator::getAtBundleBegin(instr_rbegin()); } reverse_iterator rend() { return reverse_iterator(instr_rend()); } const_reverse_iterator rend() const { return const_reverse_iterator(instr_rend()); } /// Support for MachineInstr::getNextNode(). static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) { return &MachineBasicBlock::Insts; } inline iterator_range terminators() { return make_range(getFirstTerminator(), end()); } inline iterator_range terminators() const { return make_range(getFirstTerminator(), end()); } // Machine-CFG iterators typedef std::vector::iterator pred_iterator; typedef std::vector::const_iterator const_pred_iterator; typedef std::vector::iterator succ_iterator; typedef std::vector::const_iterator const_succ_iterator; typedef std::vector::reverse_iterator pred_reverse_iterator; typedef std::vector::const_reverse_iterator const_pred_reverse_iterator; typedef std::vector::reverse_iterator succ_reverse_iterator; typedef std::vector::const_reverse_iterator const_succ_reverse_iterator; pred_iterator pred_begin() { return Predecessors.begin(); } const_pred_iterator pred_begin() const { return Predecessors.begin(); } pred_iterator pred_end() { return Predecessors.end(); } const_pred_iterator pred_end() const { return Predecessors.end(); } pred_reverse_iterator pred_rbegin() { return Predecessors.rbegin();} const_pred_reverse_iterator pred_rbegin() const { return Predecessors.rbegin();} pred_reverse_iterator pred_rend() { return Predecessors.rend(); } const_pred_reverse_iterator pred_rend() const { return Predecessors.rend(); } unsigned pred_size() const { return (unsigned)Predecessors.size(); } bool pred_empty() const { return Predecessors.empty(); } succ_iterator succ_begin() { return Successors.begin(); } const_succ_iterator succ_begin() const { return Successors.begin(); } succ_iterator succ_end() { return Successors.end(); } const_succ_iterator succ_end() const { return Successors.end(); } succ_reverse_iterator succ_rbegin() { return Successors.rbegin(); } const_succ_reverse_iterator succ_rbegin() const { return Successors.rbegin(); } succ_reverse_iterator succ_rend() { return Successors.rend(); } const_succ_reverse_iterator succ_rend() const { return Successors.rend(); } unsigned succ_size() const { return (unsigned)Successors.size(); } bool succ_empty() const { return Successors.empty(); } inline iterator_range predecessors() { return make_range(pred_begin(), pred_end()); } inline iterator_range predecessors() const { return make_range(pred_begin(), pred_end()); } inline iterator_range successors() { return make_range(succ_begin(), succ_end()); } inline iterator_range successors() const { return make_range(succ_begin(), succ_end()); } // LiveIn management methods. /// Adds the specified register as a live in. Note that it is an error to add /// the same register to the same set more than once unless the intention is /// to call sortUniqueLiveIns after all registers are added. void addLiveIn(MCPhysReg PhysReg, LaneBitmask LaneMask = LaneBitmask::getAll()) { LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask)); } void addLiveIn(const RegisterMaskPair &RegMaskPair) { LiveIns.push_back(RegMaskPair); } /// Sorts and uniques the LiveIns vector. It can be significantly faster to do /// this than repeatedly calling isLiveIn before calling addLiveIn for every /// LiveIn insertion. void sortUniqueLiveIns(); /// Clear live in list. void clearLiveIns(); /// Add PhysReg as live in to this block, and ensure that there is a copy of /// PhysReg to a virtual register of class RC. Return the virtual register /// that is a copy of the live in PhysReg. unsigned addLiveIn(MCPhysReg PhysReg, const TargetRegisterClass *RC); /// Remove the specified register from the live in set. void removeLiveIn(MCPhysReg Reg, LaneBitmask LaneMask = LaneBitmask::getAll()); /// Return true if the specified register is in the live in set. bool isLiveIn(MCPhysReg Reg, LaneBitmask LaneMask = LaneBitmask::getAll()) const; // Iteration support for live in sets. These sets are kept in sorted // order by their register number. typedef LiveInVector::const_iterator livein_iterator; livein_iterator livein_begin() const; livein_iterator livein_end() const { return LiveIns.end(); } bool livein_empty() const { return LiveIns.empty(); } iterator_range liveins() const { return make_range(livein_begin(), livein_end()); } /// Get the clobber mask for the start of this basic block. Funclets use this /// to prevent register allocation across funclet transitions. const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const; /// Get the clobber mask for the end of the basic block. /// \see getBeginClobberMask() const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const; /// Return alignment of the basic block. The alignment is specified as /// log2(bytes). unsigned getAlignment() const { return Alignment; } /// Set alignment of the basic block. The alignment is specified as /// log2(bytes). void setAlignment(unsigned Align) { Alignment = Align; } /// Returns true if the block is a landing pad. That is this basic block is /// entered via an exception handler. bool isEHPad() const { return IsEHPad; } /// Indicates the block is a landing pad. That is this basic block is entered /// via an exception handler. void setIsEHPad(bool V = true) { IsEHPad = V; } bool hasEHPadSuccessor() const; /// Returns true if this is the entry block of an EH funclet. bool isEHFuncletEntry() const { return IsEHFuncletEntry; } /// Indicates if this is the entry block of an EH funclet. void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; } /// Returns true if this is the entry block of a cleanup funclet. bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; } /// Indicates if this is the entry block of a cleanup funclet. void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; } // Code Layout methods. /// Move 'this' block before or after the specified block. This only moves /// the block, it does not modify the CFG or adjust potential fall-throughs at /// the end of the block. void moveBefore(MachineBasicBlock *NewAfter); void moveAfter(MachineBasicBlock *NewBefore); /// Update the terminator instructions in block to account for changes to the /// layout. If the block previously used a fallthrough, it may now need a /// branch, and if it previously used branching it may now be able to use a /// fallthrough. void updateTerminator(); // Machine-CFG mutators /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list /// of Succ is automatically updated. PROB parameter is stored in /// Probabilities list. The default probability is set as unknown. Mixing /// known and unknown probabilities in successor list is not allowed. When all /// successors have unknown probabilities, 1 / N is returned as the /// probability for each successor, where N is the number of successors. /// /// Note that duplicate Machine CFG edges are not allowed. void addSuccessor(MachineBasicBlock *Succ, BranchProbability Prob = BranchProbability::getUnknown()); /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list /// of Succ is automatically updated. The probability is not provided because /// BPI is not available (e.g. -O0 is used), in which case edge probabilities /// won't be used. Using this interface can save some space. void addSuccessorWithoutProb(MachineBasicBlock *Succ); /// Set successor probability of a given iterator. void setSuccProbability(succ_iterator I, BranchProbability Prob); /// Normalize probabilities of all successors so that the sum of them becomes /// one. This is usually done when the current update on this MBB is done, and /// the sum of its successors' probabilities is not guaranteed to be one. The /// user is responsible for the correct use of this function. /// MBB::removeSuccessor() has an option to do this automatically. void normalizeSuccProbs() { BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end()); } /// Validate successors' probabilities and check if the sum of them is /// approximate one. This only works in DEBUG mode. void validateSuccProbs() const; /// Remove successor from the successors list of this MachineBasicBlock. The /// Predecessors list of Succ is automatically updated. /// If NormalizeSuccProbs is true, then normalize successors' probabilities /// after the successor is removed. void removeSuccessor(MachineBasicBlock *Succ, bool NormalizeSuccProbs = false); /// Remove specified successor from the successors list of this /// MachineBasicBlock. The Predecessors list of Succ is automatically updated. /// If NormalizeSuccProbs is true, then normalize successors' probabilities /// after the successor is removed. /// Return the iterator to the element after the one removed. succ_iterator removeSuccessor(succ_iterator I, bool NormalizeSuccProbs = false); /// Replace successor OLD with NEW and update probability info. void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New); /// Transfers all the successors from MBB to this machine basic block (i.e., /// copies all the successors FromMBB and remove all the successors from /// FromMBB). void transferSuccessors(MachineBasicBlock *FromMBB); /// Transfers all the successors, as in transferSuccessors, and update PHI /// operands in the successor blocks which refer to FromMBB to refer to this. void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB); /// Return true if any of the successors have probabilities attached to them. bool hasSuccessorProbabilities() const { return !Probs.empty(); } /// Return true if the specified MBB is a predecessor of this block. bool isPredecessor(const MachineBasicBlock *MBB) const; /// Return true if the specified MBB is a successor of this block. bool isSuccessor(const MachineBasicBlock *MBB) const; /// Return true if the specified MBB will be emitted immediately after this /// block, such that if this block exits by falling through, control will /// transfer to the specified MBB. Note that MBB need not be a successor at /// all, for example if this block ends with an unconditional branch to some /// other block. bool isLayoutSuccessor(const MachineBasicBlock *MBB) const; /// Return true if the block can implicitly transfer control to the block /// after it by falling off the end of it. This should return false if it can /// reach the block after it, but it uses an explicit branch to do so (e.g., a /// table jump). True is a conservative answer. bool canFallThrough(); /// Returns a pointer to the first instruction in this block that is not a /// PHINode instruction. When adding instructions to the beginning of the /// basic block, they should be added before the returned value, not before /// the first instruction, which might be PHI. /// Returns end() is there's no non-PHI instruction. iterator getFirstNonPHI(); /// Return the first instruction in MBB after I that is not a PHI or a label. /// This is the correct point to insert lowered copies at the beginning of a /// basic block that must be before any debugging information. iterator SkipPHIsAndLabels(iterator I); /// Return the first instruction in MBB after I that is not a PHI, label or /// debug. This is the correct point to insert copies at the beginning of a /// basic block. iterator SkipPHIsLabelsAndDebug(iterator I); /// Returns an iterator to the first terminator instruction of this basic /// block. If a terminator does not exist, it returns end(). iterator getFirstTerminator(); const_iterator getFirstTerminator() const { return const_cast(this)->getFirstTerminator(); } /// Same getFirstTerminator but it ignores bundles and return an /// instr_iterator instead. instr_iterator getFirstInstrTerminator(); /// Returns an iterator to the first non-debug instruction in the basic block, /// or end(). iterator getFirstNonDebugInstr(); const_iterator getFirstNonDebugInstr() const { return const_cast(this)->getFirstNonDebugInstr(); } /// Returns an iterator to the last non-debug instruction in the basic block, /// or end(). iterator getLastNonDebugInstr(); const_iterator getLastNonDebugInstr() const { return const_cast(this)->getLastNonDebugInstr(); } /// Convenience function that returns true if the block ends in a return /// instruction. bool isReturnBlock() const { return !empty() && back().isReturn(); } /// Split the critical edge from this block to the given successor block, and /// return the newly created block, or null if splitting is not possible. /// /// This function updates LiveVariables, MachineDominatorTree, and /// MachineLoopInfo, as applicable. MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass &P); /// Check if the edge between this block and the given successor \p /// Succ, can be split. If this returns true a subsequent call to /// SplitCriticalEdge is guaranteed to return a valid basic block if /// no changes occured in the meantime. bool canSplitCriticalEdge(const MachineBasicBlock *Succ) const; void pop_front() { Insts.pop_front(); } void pop_back() { Insts.pop_back(); } void push_back(MachineInstr *MI) { Insts.push_back(MI); } /// Insert MI into the instruction list before I, possibly inside a bundle. /// /// If the insertion point is inside a bundle, MI will be added to the bundle, /// otherwise MI will not be added to any bundle. That means this function /// alone can't be used to prepend or append instructions to bundles. See /// MIBundleBuilder::insert() for a more reliable way of doing that. instr_iterator insert(instr_iterator I, MachineInstr *M); /// Insert a range of instructions into the instruction list before I. template void insert(iterator I, IT S, IT E) { assert((I == end() || I->getParent() == this) && "iterator points outside of basic block"); Insts.insert(I.getInstrIterator(), S, E); } /// Insert MI into the instruction list before I. iterator insert(iterator I, MachineInstr *MI) { assert((I == end() || I->getParent() == this) && "iterator points outside of basic block"); assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && "Cannot insert instruction with bundle flags"); return Insts.insert(I.getInstrIterator(), MI); } /// Insert MI into the instruction list after I. iterator insertAfter(iterator I, MachineInstr *MI) { assert((I == end() || I->getParent() == this) && "iterator points outside of basic block"); assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() && "Cannot insert instruction with bundle flags"); return Insts.insertAfter(I.getInstrIterator(), MI); } /// Remove an instruction from the instruction list and delete it. /// /// If the instruction is part of a bundle, the other instructions in the /// bundle will still be bundled after removing the single instruction. instr_iterator erase(instr_iterator I); /// Remove an instruction from the instruction list and delete it. /// /// If the instruction is part of a bundle, the other instructions in the /// bundle will still be bundled after removing the single instruction. instr_iterator erase_instr(MachineInstr *I) { return erase(instr_iterator(I)); } /// Remove a range of instructions from the instruction list and delete them. iterator erase(iterator I, iterator E) { return Insts.erase(I.getInstrIterator(), E.getInstrIterator()); } /// Remove an instruction or bundle from the instruction list and delete it. /// /// If I points to a bundle of instructions, they are all erased. iterator erase(iterator I) { return erase(I, std::next(I)); } /// Remove an instruction from the instruction list and delete it. /// /// If I is the head of a bundle of instructions, the whole bundle will be /// erased. iterator erase(MachineInstr *I) { return erase(iterator(I)); } /// Remove the unbundled instruction from the instruction list without /// deleting it. /// /// This function can not be used to remove bundled instructions, use /// remove_instr to remove individual instructions from a bundle. MachineInstr *remove(MachineInstr *I) { assert(!I->isBundled() && "Cannot remove bundled instructions"); return Insts.remove(instr_iterator(I)); } /// Remove the possibly bundled instruction from the instruction list /// without deleting it. /// /// If the instruction is part of a bundle, the other instructions in the /// bundle will still be bundled after removing the single instruction. MachineInstr *remove_instr(MachineInstr *I); void clear() { Insts.clear(); } /// Take an instruction from MBB 'Other' at the position From, and insert it /// into this MBB right before 'Where'. /// /// If From points to a bundle of instructions, the whole bundle is moved. void splice(iterator Where, MachineBasicBlock *Other, iterator From) { // The range splice() doesn't allow noop moves, but this one does. if (Where != From) splice(Where, Other, From, std::next(From)); } /// Take a block of instructions from MBB 'Other' in the range [From, To), /// and insert them into this MBB right before 'Where'. /// /// The instruction at 'Where' must not be included in the range of /// instructions to move. void splice(iterator Where, MachineBasicBlock *Other, iterator From, iterator To) { Insts.splice(Where.getInstrIterator(), Other->Insts, From.getInstrIterator(), To.getInstrIterator()); } /// This method unlinks 'this' from the containing function, and returns it, /// but does not delete it. MachineBasicBlock *removeFromParent(); /// This method unlinks 'this' from the containing function and deletes it. void eraseFromParent(); /// Given a machine basic block that branched to 'Old', change the code and /// CFG so that it branches to 'New' instead. void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New); /// Various pieces of code can cause excess edges in the CFG to be inserted. /// If we have proven that MBB can only branch to DestA and DestB, remove any /// other MBB successors from the CFG. DestA and DestB can be null. Besides /// DestA and DestB, retain other edges leading to LandingPads (currently /// there can be only one; we don't check or require that here). Note it is /// possible that DestA and/or DestB are LandingPads. bool CorrectExtraCFGEdges(MachineBasicBlock *DestA, MachineBasicBlock *DestB, bool IsCond); /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE /// instructions. Return UnknownLoc if there is none. DebugLoc findDebugLoc(instr_iterator MBBI); DebugLoc findDebugLoc(iterator MBBI) { return findDebugLoc(MBBI.getInstrIterator()); } /// Possible outcome of a register liveness query to computeRegisterLiveness() enum LivenessQueryResult { LQR_Live, ///< Register is known to be (at least partially) live. LQR_Dead, ///< Register is known to be fully dead. LQR_Unknown ///< Register liveness not decidable from local neighborhood. }; /// Return whether (physical) register \p Reg has been ined and not /// ed as of just before \p Before. /// /// Search is localised to a neighborhood of \p Neighborhood instructions /// before (searching for defs or kills) and \p Neighborhood instructions /// after (searching just for defs) \p Before. /// /// \p Reg must be a physical register. LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI, unsigned Reg, const_iterator Before, unsigned Neighborhood=10) const; // Debugging methods. void dump() const; void print(raw_ostream &OS, const SlotIndexes* = nullptr) const; void print(raw_ostream &OS, ModuleSlotTracker &MST, const SlotIndexes* = nullptr) const; // Printing method used by LoopInfo. void printAsOperand(raw_ostream &OS, bool PrintType = true) const; /// MachineBasicBlocks are uniquely numbered at the function level, unless /// they're not in a MachineFunction yet, in which case this will return -1. int getNumber() const { return Number; } void setNumber(int N) { Number = N; } /// Return the MCSymbol for this basic block. MCSymbol *getSymbol() const; private: /// Return probability iterator corresponding to the I successor iterator. probability_iterator getProbabilityIterator(succ_iterator I); const_probability_iterator getProbabilityIterator(const_succ_iterator I) const; friend class MachineBranchProbabilityInfo; friend class MIPrinter; /// Return probability of the edge from this block to MBB. This method should /// NOT be called directly, but by using getEdgeProbability method from /// MachineBranchProbabilityInfo class. BranchProbability getSuccProbability(const_succ_iterator Succ) const; // Methods used to maintain doubly linked list of blocks... friend struct ilist_callback_traits; // Machine-CFG mutators /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this /// unless you know what you're doing, because it doesn't update Pred's /// successors list. Use Pred->addSuccessor instead. void addPredecessor(MachineBasicBlock *Pred); /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this /// unless you know what you're doing, because it doesn't update Pred's /// successors list. Use Pred->removeSuccessor instead. void removePredecessor(MachineBasicBlock *Pred); }; raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB); // This is useful when building IndexedMaps keyed on basic block pointers. struct MBB2NumberFunctor : public std::unary_function { unsigned operator()(const MachineBasicBlock *MBB) const { return MBB->getNumber(); } }; //===--------------------------------------------------------------------===// // GraphTraits specializations for machine basic block graphs (machine-CFGs) //===--------------------------------------------------------------------===// // Provide specializations of GraphTraits to be able to treat a // MachineFunction as a graph of MachineBasicBlocks. // template <> struct GraphTraits { typedef MachineBasicBlock *NodeRef; typedef MachineBasicBlock::succ_iterator ChildIteratorType; static NodeRef getEntryNode(MachineBasicBlock *BB) { return BB; } static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } }; template <> struct GraphTraits { typedef const MachineBasicBlock *NodeRef; typedef MachineBasicBlock::const_succ_iterator ChildIteratorType; static NodeRef getEntryNode(const MachineBasicBlock *BB) { return BB; } static ChildIteratorType child_begin(NodeRef N) { return N->succ_begin(); } static ChildIteratorType child_end(NodeRef N) { return N->succ_end(); } }; // Provide specializations of GraphTraits to be able to treat a // MachineFunction as a graph of MachineBasicBlocks and to walk it // in inverse order. Inverse order for a function is considered // to be when traversing the predecessor edges of a MBB // instead of the successor edges. // template <> struct GraphTraits > { typedef MachineBasicBlock *NodeRef; typedef MachineBasicBlock::pred_iterator ChildIteratorType; static NodeRef getEntryNode(Inverse G) { return G.Graph; } static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } }; template <> struct GraphTraits > { typedef const MachineBasicBlock *NodeRef; typedef MachineBasicBlock::const_pred_iterator ChildIteratorType; static NodeRef getEntryNode(Inverse G) { return G.Graph; } static ChildIteratorType child_begin(NodeRef N) { return N->pred_begin(); } static ChildIteratorType child_end(NodeRef N) { return N->pred_end(); } }; /// MachineInstrSpan provides an interface to get an iteration range /// containing the instruction it was initialized with, along with all /// those instructions inserted prior to or following that instruction /// at some point after the MachineInstrSpan is constructed. class MachineInstrSpan { MachineBasicBlock &MBB; MachineBasicBlock::iterator I, B, E; public: MachineInstrSpan(MachineBasicBlock::iterator I) : MBB(*I->getParent()), I(I), B(I == MBB.begin() ? MBB.end() : std::prev(I)), E(std::next(I)) {} MachineBasicBlock::iterator begin() { return B == MBB.end() ? MBB.begin() : std::next(B); } MachineBasicBlock::iterator end() { return E; } bool empty() { return begin() == end(); } MachineBasicBlock::iterator getInitial() { return I; } }; /// Increment \p It until it points to a non-debug instruction or to \p End /// and return the resulting iterator. This function should only be used /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, /// const_instr_iterator} and the respective reverse iterators. template inline IterT skipDebugInstructionsForward(IterT It, IterT End) { while (It != End && It->isDebugValue()) It++; return It; } /// Decrement \p It until it points to a non-debug instruction or to \p Begin /// and return the resulting iterator. This function should only be used /// MachineBasicBlock::{iterator, const_iterator, instr_iterator, /// const_instr_iterator} and the respective reverse iterators. template inline IterT skipDebugInstructionsBackward(IterT It, IterT Begin) { while (It != Begin && It->isDebugValue()) It--; return It; } } // End llvm namespace #endif