1 //===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Collect the sequence of machine instructions for a basic block.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
15 #define LLVM_CODEGEN_MACHINEBASICBLOCK_H
17 #include "llvm/ADT/GraphTraits.h"
18 #include "llvm/CodeGen/MachineInstr.h"
19 #include "llvm/Support/DataTypes.h"
26 class MachineFunction;
32 class MachineBranchProbabilityInfo;
35 struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
37 mutable ilist_half_node<MachineInstr> Sentinel;
39 // this is only set by the MachineBasicBlock owning the LiveList
40 friend class MachineBasicBlock;
41 MachineBasicBlock* Parent;
44 MachineInstr *createSentinel() const {
45 return static_cast<MachineInstr*>(&Sentinel);
47 void destroySentinel(MachineInstr *) const {}
49 MachineInstr *provideInitialHead() const { return createSentinel(); }
50 MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); }
51 static void noteHead(MachineInstr*, MachineInstr*) {}
53 void addNodeToList(MachineInstr* N);
54 void removeNodeFromList(MachineInstr* N);
55 void transferNodesFromList(ilist_traits &SrcTraits,
56 ilist_iterator<MachineInstr> first,
57 ilist_iterator<MachineInstr> last);
58 void deleteNode(MachineInstr *N);
60 void createNode(const MachineInstr &);
63 class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
64 typedef ilist<MachineInstr> Instructions;
69 /// A flag tracking whether the weights of all successors are normalized.
70 bool AreSuccWeightsNormalized;
72 MachineFunction *xParent;
74 /// Keep track of the predecessor / successor basic blocks.
75 std::vector<MachineBasicBlock *> Predecessors;
76 std::vector<MachineBasicBlock *> Successors;
78 /// Keep track of the weights to the successors. This vector has the same
79 /// order as Successors, or it is empty if we don't use it (disable
81 std::vector<uint32_t> Weights;
82 typedef std::vector<uint32_t>::iterator weight_iterator;
83 typedef std::vector<uint32_t>::const_iterator const_weight_iterator;
85 /// Keep track of the physical registers that are livein of the basicblock.
86 std::vector<unsigned> LiveIns;
88 /// Alignment of the basic block. Zero if the basic block does not need to be
89 /// aligned. The alignment is specified as log2(bytes).
92 /// Indicate that this basic block is entered via an exception handler.
95 /// Indicate that this basic block is potentially the target of an indirect
99 /// \brief since getSymbol is a relatively heavy-weight operation, the symbol
100 /// is only computed once and is cached.
101 mutable MCSymbol *CachedMCSymbol;
103 // Intrusive list support
104 MachineBasicBlock() {}
106 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
108 ~MachineBasicBlock();
110 // MachineBasicBlocks are allocated and owned by MachineFunction.
111 friend class MachineFunction;
114 /// Return the LLVM basic block that this instance corresponded to originally.
115 /// Note that this may be NULL if this instance does not correspond directly
116 /// to an LLVM basic block.
117 const BasicBlock *getBasicBlock() const { return BB; }
119 /// Return the name of the corresponding LLVM basic block, or "(null)".
120 StringRef getName() const;
122 /// Return a formatted string to identify this block and its parent function.
123 std::string getFullName() const;
125 /// Test whether this block is potentially the target of an indirect branch.
126 bool hasAddressTaken() const { return AddressTaken; }
128 /// Set this block to reflect that it potentially is the target of an indirect
130 void setHasAddressTaken() { AddressTaken = true; }
132 /// Return the MachineFunction containing this basic block.
133 const MachineFunction *getParent() const { return xParent; }
134 MachineFunction *getParent() { return xParent; }
136 /// Return whether all weights of successors are normalized.
137 bool areSuccWeightsNormalized() const { return AreSuccWeightsNormalized; }
139 /// MachineBasicBlock iterator that automatically skips over MIs that are
140 /// inside bundles (i.e. walk top level MIs only).
141 template<typename Ty, typename IterTy>
142 class bundle_iterator
143 : public std::iterator<std::bidirectional_iterator_tag, Ty, ptrdiff_t> {
147 bundle_iterator(IterTy mii) : MII(mii) {}
149 bundle_iterator(Ty &mi) : MII(mi) {
150 assert(!mi.isBundledWithPred() &&
151 "It's not legal to initialize bundle_iterator with a bundled MI");
153 bundle_iterator(Ty *mi) : MII(mi) {
154 assert((!mi || !mi->isBundledWithPred()) &&
155 "It's not legal to initialize bundle_iterator with a bundled MI");
157 // Template allows conversion from const to nonconst.
158 template<class OtherTy, class OtherIterTy>
159 bundle_iterator(const bundle_iterator<OtherTy, OtherIterTy> &I)
160 : MII(I.getInstrIterator()) {}
161 bundle_iterator() : MII(nullptr) {}
163 Ty &operator*() const { return *MII; }
164 Ty *operator->() const { return &operator*(); }
166 operator Ty*() const { return MII; }
168 bool operator==(const bundle_iterator &x) const {
171 bool operator!=(const bundle_iterator &x) const {
172 return !operator==(x);
175 // Increment and decrement operators...
176 bundle_iterator &operator--() { // predecrement - Back up
178 while (MII->isBundledWithPred());
181 bundle_iterator &operator++() { // preincrement - Advance
182 while (MII->isBundledWithSucc())
187 bundle_iterator operator--(int) { // postdecrement operators...
188 bundle_iterator tmp = *this;
192 bundle_iterator operator++(int) { // postincrement operators...
193 bundle_iterator tmp = *this;
198 IterTy getInstrIterator() const {
203 typedef Instructions::iterator instr_iterator;
204 typedef Instructions::const_iterator const_instr_iterator;
205 typedef std::reverse_iterator<instr_iterator> reverse_instr_iterator;
207 std::reverse_iterator<const_instr_iterator> const_reverse_instr_iterator;
210 bundle_iterator<MachineInstr,instr_iterator> iterator;
212 bundle_iterator<const MachineInstr,const_instr_iterator> const_iterator;
213 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
214 typedef std::reverse_iterator<iterator> reverse_iterator;
217 unsigned size() const { return (unsigned)Insts.size(); }
218 bool empty() const { return Insts.empty(); }
220 MachineInstr &instr_front() { return Insts.front(); }
221 MachineInstr &instr_back() { return Insts.back(); }
222 const MachineInstr &instr_front() const { return Insts.front(); }
223 const MachineInstr &instr_back() const { return Insts.back(); }
225 MachineInstr &front() { return Insts.front(); }
226 MachineInstr &back() { return *--end(); }
227 const MachineInstr &front() const { return Insts.front(); }
228 const MachineInstr &back() const { return *--end(); }
230 instr_iterator instr_begin() { return Insts.begin(); }
231 const_instr_iterator instr_begin() const { return Insts.begin(); }
232 instr_iterator instr_end() { return Insts.end(); }
233 const_instr_iterator instr_end() const { return Insts.end(); }
234 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
235 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
236 reverse_instr_iterator instr_rend () { return Insts.rend(); }
237 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
239 iterator begin() { return instr_begin(); }
240 const_iterator begin() const { return instr_begin(); }
241 iterator end () { return instr_end(); }
242 const_iterator end () const { return instr_end(); }
243 reverse_iterator rbegin() { return instr_rbegin(); }
244 const_reverse_iterator rbegin() const { return instr_rbegin(); }
245 reverse_iterator rend () { return instr_rend(); }
246 const_reverse_iterator rend () const { return instr_rend(); }
248 inline iterator_range<iterator> terminators() {
249 return iterator_range<iterator>(getFirstTerminator(), end());
251 inline iterator_range<const_iterator> terminators() const {
252 return iterator_range<const_iterator>(getFirstTerminator(), end());
255 // Machine-CFG iterators
256 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
257 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
258 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
259 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
260 typedef std::vector<MachineBasicBlock *>::reverse_iterator
261 pred_reverse_iterator;
262 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
263 const_pred_reverse_iterator;
264 typedef std::vector<MachineBasicBlock *>::reverse_iterator
265 succ_reverse_iterator;
266 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
267 const_succ_reverse_iterator;
268 pred_iterator pred_begin() { return Predecessors.begin(); }
269 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
270 pred_iterator pred_end() { return Predecessors.end(); }
271 const_pred_iterator pred_end() const { return Predecessors.end(); }
272 pred_reverse_iterator pred_rbegin()
273 { return Predecessors.rbegin();}
274 const_pred_reverse_iterator pred_rbegin() const
275 { return Predecessors.rbegin();}
276 pred_reverse_iterator pred_rend()
277 { return Predecessors.rend(); }
278 const_pred_reverse_iterator pred_rend() const
279 { return Predecessors.rend(); }
280 unsigned pred_size() const {
281 return (unsigned)Predecessors.size();
283 bool pred_empty() const { return Predecessors.empty(); }
284 succ_iterator succ_begin() { return Successors.begin(); }
285 const_succ_iterator succ_begin() const { return Successors.begin(); }
286 succ_iterator succ_end() { return Successors.end(); }
287 const_succ_iterator succ_end() const { return Successors.end(); }
288 succ_reverse_iterator succ_rbegin()
289 { return Successors.rbegin(); }
290 const_succ_reverse_iterator succ_rbegin() const
291 { return Successors.rbegin(); }
292 succ_reverse_iterator succ_rend()
293 { return Successors.rend(); }
294 const_succ_reverse_iterator succ_rend() const
295 { return Successors.rend(); }
296 unsigned succ_size() const {
297 return (unsigned)Successors.size();
299 bool succ_empty() const { return Successors.empty(); }
301 inline iterator_range<pred_iterator> predecessors() {
302 return iterator_range<pred_iterator>(pred_begin(), pred_end());
304 inline iterator_range<const_pred_iterator> predecessors() const {
305 return iterator_range<const_pred_iterator>(pred_begin(), pred_end());
307 inline iterator_range<succ_iterator> successors() {
308 return iterator_range<succ_iterator>(succ_begin(), succ_end());
310 inline iterator_range<const_succ_iterator> successors() const {
311 return iterator_range<const_succ_iterator>(succ_begin(), succ_end());
314 // LiveIn management methods.
316 /// Adds the specified register as a live in. Note that it is an error to add
317 /// the same register to the same set more than once unless the intention is
318 /// to call sortUniqueLiveIns after all registers are added.
319 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
321 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do
322 /// this than repeatedly calling isLiveIn before calling addLiveIn for every
323 /// LiveIn insertion.
324 void sortUniqueLiveIns() {
325 std::sort(LiveIns.begin(), LiveIns.end());
326 LiveIns.erase(std::unique(LiveIns.begin(), LiveIns.end()), LiveIns.end());
329 /// Add PhysReg as live in to this block, and ensure that there is a copy of
330 /// PhysReg to a virtual register of class RC. Return the virtual register
331 /// that is a copy of the live in PhysReg.
332 unsigned addLiveIn(unsigned PhysReg, const TargetRegisterClass *RC);
334 /// Remove the specified register from the live in set.
335 void removeLiveIn(unsigned Reg);
337 /// Return true if the specified register is in the live in set.
338 bool isLiveIn(unsigned Reg) const;
340 // Iteration support for live in sets. These sets are kept in sorted
341 // order by their register number.
342 typedef std::vector<unsigned>::const_iterator livein_iterator;
343 livein_iterator livein_begin() const { return LiveIns.begin(); }
344 livein_iterator livein_end() const { return LiveIns.end(); }
345 bool livein_empty() const { return LiveIns.empty(); }
347 /// Return alignment of the basic block. The alignment is specified as
349 unsigned getAlignment() const { return Alignment; }
351 /// Set alignment of the basic block. The alignment is specified as
353 void setAlignment(unsigned Align) { Alignment = Align; }
355 /// Returns true if the block is a landing pad. That is this basic block is
356 /// entered via an exception handler.
357 bool isLandingPad() const { return IsLandingPad; }
359 /// Indicates the block is a landing pad. That is this basic block is entered
360 /// via an exception handler.
361 void setIsLandingPad(bool V = true) { IsLandingPad = V; }
363 /// If this block has a successor that is a landing pad, return it. Otherwise
365 const MachineBasicBlock *getLandingPadSuccessor() const;
367 // Code Layout methods.
369 /// Move 'this' block before or after the specified block. This only moves
370 /// the block, it does not modify the CFG or adjust potential fall-throughs at
371 /// the end of the block.
372 void moveBefore(MachineBasicBlock *NewAfter);
373 void moveAfter(MachineBasicBlock *NewBefore);
375 /// Update the terminator instructions in block to account for changes to the
376 /// layout. If the block previously used a fallthrough, it may now need a
377 /// branch, and if it previously used branching it may now be able to use a
379 void updateTerminator();
381 // Machine-CFG mutators
383 /// Add succ as a successor of this MachineBasicBlock. The Predecessors list
384 /// of succ is automatically updated. WEIGHT parameter is stored in Weights
385 /// list and it may be used by MachineBranchProbabilityInfo analysis to
386 /// calculate branch probability.
388 /// Note that duplicate Machine CFG edges are not allowed.
389 void addSuccessor(MachineBasicBlock *succ, uint32_t weight = 0);
391 /// Set successor weight of a given iterator.
392 void setSuccWeight(succ_iterator I, uint32_t weight);
394 /// Normalize all succesor weights so that the sum of them does not exceed
395 /// UINT32_MAX. Return true if the weights are modified and false otherwise.
396 /// Note that weights that are modified after calling this function are not
397 /// guaranteed to be normalized.
398 bool normalizeSuccWeights();
400 /// Remove successor from the successors list of this MachineBasicBlock. The
401 /// Predecessors list of succ is automatically updated.
402 void removeSuccessor(MachineBasicBlock *succ);
404 /// Remove specified successor from the successors list of this
405 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
406 /// Return the iterator to the element after the one removed.
407 succ_iterator removeSuccessor(succ_iterator I);
409 /// Replace successor OLD with NEW and update weight info.
410 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
412 /// Transfers all the successors from MBB to this machine basic block (i.e.,
413 /// copies all the successors fromMBB and remove all the successors from
415 void transferSuccessors(MachineBasicBlock *fromMBB);
417 /// Transfers all the successors, as in transferSuccessors, and update PHI
418 /// operands in the successor blocks which refer to fromMBB to refer to this.
419 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB);
421 /// Return true if any of the successors have weights attached to them.
422 bool hasSuccessorWeights() const { return !Weights.empty(); }
424 /// Return true if the specified MBB is a predecessor of this block.
425 bool isPredecessor(const MachineBasicBlock *MBB) const;
427 /// Return true if the specified MBB is a successor of this block.
428 bool isSuccessor(const MachineBasicBlock *MBB) const;
430 /// Return true if the specified MBB will be emitted immediately after this
431 /// block, such that if this block exits by falling through, control will
432 /// transfer to the specified MBB. Note that MBB need not be a successor at
433 /// all, for example if this block ends with an unconditional branch to some
435 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
437 /// Return true if the block can implicitly transfer control to the block
438 /// after it by falling off the end of it. This should return false if it can
439 /// reach the block after it, but it uses an explicit branch to do so (e.g., a
440 /// table jump). True is a conservative answer.
441 bool canFallThrough();
443 /// Returns a pointer to the first instruction in this block that is not a
444 /// PHINode instruction. When adding instructions to the beginning of the
445 /// basic block, they should be added before the returned value, not before
446 /// the first instruction, which might be PHI.
447 /// Returns end() is there's no non-PHI instruction.
448 iterator getFirstNonPHI();
450 /// Return the first instruction in MBB after I that is not a PHI or a label.
451 /// This is the correct point to insert copies at the beginning of a basic
453 iterator SkipPHIsAndLabels(iterator I);
455 /// Returns an iterator to the first terminator instruction of this basic
456 /// block. If a terminator does not exist, it returns end().
457 iterator getFirstTerminator();
458 const_iterator getFirstTerminator() const {
459 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
462 /// Same getFirstTerminator but it ignores bundles and return an
463 /// instr_iterator instead.
464 instr_iterator getFirstInstrTerminator();
466 /// Returns an iterator to the first non-debug instruction in the basic block,
468 iterator getFirstNonDebugInstr();
469 const_iterator getFirstNonDebugInstr() const {
470 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr();
473 /// Returns an iterator to the last non-debug instruction in the basic block,
475 iterator getLastNonDebugInstr();
476 const_iterator getLastNonDebugInstr() const {
477 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
480 /// Split the critical edge from this block to the given successor block, and
481 /// return the newly created block, or null if splitting is not possible.
483 /// This function updates LiveVariables, MachineDominatorTree, and
484 /// MachineLoopInfo, as applicable.
485 MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P);
487 void pop_front() { Insts.pop_front(); }
488 void pop_back() { Insts.pop_back(); }
489 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
491 /// Insert MI into the instruction list before I, possibly inside a bundle.
493 /// If the insertion point is inside a bundle, MI will be added to the bundle,
494 /// otherwise MI will not be added to any bundle. That means this function
495 /// alone can't be used to prepend or append instructions to bundles. See
496 /// MIBundleBuilder::insert() for a more reliable way of doing that.
497 instr_iterator insert(instr_iterator I, MachineInstr *M);
499 /// Insert a range of instructions into the instruction list before I.
500 template<typename IT>
501 void insert(iterator I, IT S, IT E) {
502 assert((I == end() || I->getParent() == this) &&
503 "iterator points outside of basic block");
504 Insts.insert(I.getInstrIterator(), S, E);
507 /// Insert MI into the instruction list before I.
508 iterator insert(iterator I, MachineInstr *MI) {
509 assert((I == end() || I->getParent() == this) &&
510 "iterator points outside of basic block");
511 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
512 "Cannot insert instruction with bundle flags");
513 return Insts.insert(I.getInstrIterator(), MI);
516 /// Insert MI into the instruction list after I.
517 iterator insertAfter(iterator I, MachineInstr *MI) {
518 assert((I == end() || I->getParent() == this) &&
519 "iterator points outside of basic block");
520 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
521 "Cannot insert instruction with bundle flags");
522 return Insts.insertAfter(I.getInstrIterator(), MI);
525 /// Remove an instruction from the instruction list and delete it.
527 /// If the instruction is part of a bundle, the other instructions in the
528 /// bundle will still be bundled after removing the single instruction.
529 instr_iterator erase(instr_iterator I);
531 /// Remove an instruction from the instruction list and delete it.
533 /// If the instruction is part of a bundle, the other instructions in the
534 /// bundle will still be bundled after removing the single instruction.
535 instr_iterator erase_instr(MachineInstr *I) {
536 return erase(instr_iterator(I));
539 /// Remove a range of instructions from the instruction list and delete them.
540 iterator erase(iterator I, iterator E) {
541 return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
544 /// Remove an instruction or bundle from the instruction list and delete it.
546 /// If I points to a bundle of instructions, they are all erased.
547 iterator erase(iterator I) {
548 return erase(I, std::next(I));
551 /// Remove an instruction from the instruction list and delete it.
553 /// If I is the head of a bundle of instructions, the whole bundle will be
555 iterator erase(MachineInstr *I) {
556 return erase(iterator(I));
559 /// Remove the unbundled instruction from the instruction list without
562 /// This function can not be used to remove bundled instructions, use
563 /// remove_instr to remove individual instructions from a bundle.
564 MachineInstr *remove(MachineInstr *I) {
565 assert(!I->isBundled() && "Cannot remove bundled instructions");
566 return Insts.remove(I);
569 /// Remove the possibly bundled instruction from the instruction list
570 /// without deleting it.
572 /// If the instruction is part of a bundle, the other instructions in the
573 /// bundle will still be bundled after removing the single instruction.
574 MachineInstr *remove_instr(MachineInstr *I);
580 /// Take an instruction from MBB 'Other' at the position From, and insert it
581 /// into this MBB right before 'Where'.
583 /// If From points to a bundle of instructions, the whole bundle is moved.
584 void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
585 // The range splice() doesn't allow noop moves, but this one does.
587 splice(Where, Other, From, std::next(From));
590 /// Take a block of instructions from MBB 'Other' in the range [From, To),
591 /// and insert them into this MBB right before 'Where'.
593 /// The instruction at 'Where' must not be included in the range of
594 /// instructions to move.
595 void splice(iterator Where, MachineBasicBlock *Other,
596 iterator From, iterator To) {
597 Insts.splice(Where.getInstrIterator(), Other->Insts,
598 From.getInstrIterator(), To.getInstrIterator());
601 /// This method unlinks 'this' from the containing function, and returns it,
602 /// but does not delete it.
603 MachineBasicBlock *removeFromParent();
605 /// This method unlinks 'this' from the containing function and deletes it.
606 void eraseFromParent();
608 /// Given a machine basic block that branched to 'Old', change the code and
609 /// CFG so that it branches to 'New' instead.
610 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
612 /// Various pieces of code can cause excess edges in the CFG to be inserted.
613 /// If we have proven that MBB can only branch to DestA and DestB, remove any
614 /// other MBB successors from the CFG. DestA and DestB can be null. Besides
615 /// DestA and DestB, retain other edges leading to LandingPads (currently
616 /// there can be only one; we don't check or require that here). Note it is
617 /// possible that DestA and/or DestB are LandingPads.
618 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
619 MachineBasicBlock *DestB,
622 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE
623 /// instructions. Return UnknownLoc if there is none.
624 DebugLoc findDebugLoc(instr_iterator MBBI);
625 DebugLoc findDebugLoc(iterator MBBI) {
626 return findDebugLoc(MBBI.getInstrIterator());
629 /// Possible outcome of a register liveness query to computeRegisterLiveness()
630 enum LivenessQueryResult {
631 LQR_Live, ///< Register is known to be live.
632 LQR_OverlappingLive, ///< Register itself is not live, but some overlapping
634 LQR_Dead, ///< Register is known to be dead.
635 LQR_Unknown ///< Register liveness not decidable from local
639 /// Return whether (physical) register \p Reg has been <def>ined and not
640 /// <kill>ed as of just before \p Before.
642 /// Search is localised to a neighborhood of \p Neighborhood instructions
643 /// before (searching for defs or kills) and \p Neighborhood instructions
644 /// after (searching just for defs) \p Before.
646 /// \p Reg must be a physical register.
647 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
649 const_iterator Before,
650 unsigned Neighborhood=10) const;
652 // Debugging methods.
654 void print(raw_ostream &OS, SlotIndexes* = nullptr) const;
655 void print(raw_ostream &OS, ModuleSlotTracker &MST,
656 SlotIndexes * = nullptr) const;
658 // Printing method used by LoopInfo.
659 void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
661 /// MachineBasicBlocks are uniquely numbered at the function level, unless
662 /// they're not in a MachineFunction yet, in which case this will return -1.
663 int getNumber() const { return Number; }
664 void setNumber(int N) { Number = N; }
666 /// Return the MCSymbol for this basic block.
667 MCSymbol *getSymbol() const;
671 /// Return weight iterator corresponding to the I successor iterator.
672 weight_iterator getWeightIterator(succ_iterator I);
673 const_weight_iterator getWeightIterator(const_succ_iterator I) const;
675 friend class MachineBranchProbabilityInfo;
676 friend class MIRPrinter;
678 /// Return weight of the edge from this block to MBB. This method should NOT
679 /// be called directly, but by using getEdgeWeight method from
680 /// MachineBranchProbabilityInfo class.
681 uint32_t getSuccWeight(const_succ_iterator Succ) const;
684 // Methods used to maintain doubly linked list of blocks...
685 friend struct ilist_traits<MachineBasicBlock>;
687 // Machine-CFG mutators
689 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
690 /// unless you know what you're doing, because it doesn't update pred's
691 /// successors list. Use pred->addSuccessor instead.
692 void addPredecessor(MachineBasicBlock *pred);
694 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
695 /// unless you know what you're doing, because it doesn't update pred's
696 /// successors list. Use pred->removeSuccessor instead.
697 void removePredecessor(MachineBasicBlock *pred);
700 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
702 // This is useful when building IndexedMaps keyed on basic block pointers.
703 struct MBB2NumberFunctor :
704 public std::unary_function<const MachineBasicBlock*, unsigned> {
705 unsigned operator()(const MachineBasicBlock *MBB) const {
706 return MBB->getNumber();
710 //===--------------------------------------------------------------------===//
711 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
712 //===--------------------------------------------------------------------===//
714 // Provide specializations of GraphTraits to be able to treat a
715 // MachineFunction as a graph of MachineBasicBlocks.
718 template <> struct GraphTraits<MachineBasicBlock *> {
719 typedef MachineBasicBlock NodeType;
720 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
722 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
723 static inline ChildIteratorType child_begin(NodeType *N) {
724 return N->succ_begin();
726 static inline ChildIteratorType child_end(NodeType *N) {
727 return N->succ_end();
731 template <> struct GraphTraits<const MachineBasicBlock *> {
732 typedef const MachineBasicBlock NodeType;
733 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
735 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
736 static inline ChildIteratorType child_begin(NodeType *N) {
737 return N->succ_begin();
739 static inline ChildIteratorType child_end(NodeType *N) {
740 return N->succ_end();
744 // Provide specializations of GraphTraits to be able to treat a
745 // MachineFunction as a graph of MachineBasicBlocks and to walk it
746 // in inverse order. Inverse order for a function is considered
747 // to be when traversing the predecessor edges of a MBB
748 // instead of the successor edges.
750 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
751 typedef MachineBasicBlock NodeType;
752 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
753 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
756 static inline ChildIteratorType child_begin(NodeType *N) {
757 return N->pred_begin();
759 static inline ChildIteratorType child_end(NodeType *N) {
760 return N->pred_end();
764 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
765 typedef const MachineBasicBlock NodeType;
766 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
767 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
770 static inline ChildIteratorType child_begin(NodeType *N) {
771 return N->pred_begin();
773 static inline ChildIteratorType child_end(NodeType *N) {
774 return N->pred_end();
780 /// MachineInstrSpan provides an interface to get an iteration range
781 /// containing the instruction it was initialized with, along with all
782 /// those instructions inserted prior to or following that instruction
783 /// at some point after the MachineInstrSpan is constructed.
784 class MachineInstrSpan {
785 MachineBasicBlock &MBB;
786 MachineBasicBlock::iterator I, B, E;
788 MachineInstrSpan(MachineBasicBlock::iterator I)
789 : MBB(*I->getParent()),
791 B(I == MBB.begin() ? MBB.end() : std::prev(I)),
794 MachineBasicBlock::iterator begin() {
795 return B == MBB.end() ? MBB.begin() : std::next(B);
797 MachineBasicBlock::iterator end() { return E; }
798 bool empty() { return begin() == end(); }
800 MachineBasicBlock::iterator getInitial() { return I; }
803 } // End llvm namespace