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/MC/MCRegisterInfo.h"
20 #include "llvm/Support/DataTypes.h"
27 class MachineFunction;
33 class MachineBranchProbabilityInfo;
36 struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
38 mutable ilist_half_node<MachineInstr> Sentinel;
40 // this is only set by the MachineBasicBlock owning the LiveList
41 friend class MachineBasicBlock;
42 MachineBasicBlock* Parent;
45 MachineInstr *createSentinel() const {
46 return static_cast<MachineInstr*>(&Sentinel);
48 void destroySentinel(MachineInstr *) const {}
50 MachineInstr *provideInitialHead() const { return createSentinel(); }
51 MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); }
52 static void noteHead(MachineInstr*, MachineInstr*) {}
54 void addNodeToList(MachineInstr* N);
55 void removeNodeFromList(MachineInstr* N);
56 void transferNodesFromList(ilist_traits &SrcTraits,
57 ilist_iterator<MachineInstr> first,
58 ilist_iterator<MachineInstr> last);
59 void deleteNode(MachineInstr *N);
61 void createNode(const MachineInstr &);
64 class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
65 typedef ilist<MachineInstr> Instructions;
69 MachineFunction *xParent;
71 /// Keep track of the predecessor / successor basic blocks.
72 std::vector<MachineBasicBlock *> Predecessors;
73 std::vector<MachineBasicBlock *> Successors;
75 /// Keep track of the weights to the successors. This vector has the same
76 /// order as Successors, or it is empty if we don't use it (disable
78 std::vector<uint32_t> Weights;
79 typedef std::vector<uint32_t>::iterator weight_iterator;
80 typedef std::vector<uint32_t>::const_iterator const_weight_iterator;
82 /// Keep track of the physical registers that are livein of the basicblock.
83 typedef std::vector<MCPhysReg> LiveInVector;
86 /// Alignment of the basic block. Zero if the basic block does not need to be
87 /// aligned. The alignment is specified as log2(bytes).
90 /// Indicate that this basic block is entered via an exception handler.
93 /// Indicate that this basic block is potentially the target of an indirect
97 /// \brief since getSymbol is a relatively heavy-weight operation, the symbol
98 /// is only computed once and is cached.
99 mutable MCSymbol *CachedMCSymbol;
101 // Intrusive list support
102 MachineBasicBlock() {}
104 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
106 ~MachineBasicBlock();
108 // MachineBasicBlocks are allocated and owned by MachineFunction.
109 friend class MachineFunction;
112 /// Return the LLVM basic block that this instance corresponded to originally.
113 /// Note that this may be NULL if this instance does not correspond directly
114 /// to an LLVM basic block.
115 const BasicBlock *getBasicBlock() const { return BB; }
117 /// Return the name of the corresponding LLVM basic block, or "(null)".
118 StringRef getName() const;
120 /// Return a formatted string to identify this block and its parent function.
121 std::string getFullName() const;
123 /// Test whether this block is potentially the target of an indirect branch.
124 bool hasAddressTaken() const { return AddressTaken; }
126 /// Set this block to reflect that it potentially is the target of an indirect
128 void setHasAddressTaken() { AddressTaken = true; }
130 /// Return the MachineFunction containing this basic block.
131 const MachineFunction *getParent() const { return xParent; }
132 MachineFunction *getParent() { return xParent; }
134 /// MachineBasicBlock iterator that automatically skips over MIs that are
135 /// inside bundles (i.e. walk top level MIs only).
136 template<typename Ty, typename IterTy>
137 class bundle_iterator
138 : public std::iterator<std::bidirectional_iterator_tag, Ty, ptrdiff_t> {
142 bundle_iterator(IterTy mii) : MII(mii) {}
144 bundle_iterator(Ty &mi) : MII(mi) {
145 assert(!mi.isBundledWithPred() &&
146 "It's not legal to initialize bundle_iterator with a bundled MI");
148 bundle_iterator(Ty *mi) : MII(mi) {
149 assert((!mi || !mi->isBundledWithPred()) &&
150 "It's not legal to initialize bundle_iterator with a bundled MI");
152 // Template allows conversion from const to nonconst.
153 template<class OtherTy, class OtherIterTy>
154 bundle_iterator(const bundle_iterator<OtherTy, OtherIterTy> &I)
155 : MII(I.getInstrIterator()) {}
156 bundle_iterator() : MII(nullptr) {}
158 Ty &operator*() const { return *MII; }
159 Ty *operator->() const { return &operator*(); }
161 operator Ty*() const { return MII; }
163 bool operator==(const bundle_iterator &x) const {
166 bool operator!=(const bundle_iterator &x) const {
167 return !operator==(x);
170 // Increment and decrement operators...
171 bundle_iterator &operator--() { // predecrement - Back up
173 while (MII->isBundledWithPred());
176 bundle_iterator &operator++() { // preincrement - Advance
177 while (MII->isBundledWithSucc())
182 bundle_iterator operator--(int) { // postdecrement operators...
183 bundle_iterator tmp = *this;
187 bundle_iterator operator++(int) { // postincrement operators...
188 bundle_iterator tmp = *this;
193 IterTy getInstrIterator() const {
198 typedef Instructions::iterator instr_iterator;
199 typedef Instructions::const_iterator const_instr_iterator;
200 typedef std::reverse_iterator<instr_iterator> reverse_instr_iterator;
202 std::reverse_iterator<const_instr_iterator> const_reverse_instr_iterator;
205 bundle_iterator<MachineInstr,instr_iterator> iterator;
207 bundle_iterator<const MachineInstr,const_instr_iterator> const_iterator;
208 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
209 typedef std::reverse_iterator<iterator> reverse_iterator;
212 unsigned size() const { return (unsigned)Insts.size(); }
213 bool empty() const { return Insts.empty(); }
215 MachineInstr &instr_front() { return Insts.front(); }
216 MachineInstr &instr_back() { return Insts.back(); }
217 const MachineInstr &instr_front() const { return Insts.front(); }
218 const MachineInstr &instr_back() const { return Insts.back(); }
220 MachineInstr &front() { return Insts.front(); }
221 MachineInstr &back() { return *--end(); }
222 const MachineInstr &front() const { return Insts.front(); }
223 const MachineInstr &back() const { return *--end(); }
225 instr_iterator instr_begin() { return Insts.begin(); }
226 const_instr_iterator instr_begin() const { return Insts.begin(); }
227 instr_iterator instr_end() { return Insts.end(); }
228 const_instr_iterator instr_end() const { return Insts.end(); }
229 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
230 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
231 reverse_instr_iterator instr_rend () { return Insts.rend(); }
232 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
234 iterator begin() { return instr_begin(); }
235 const_iterator begin() const { return instr_begin(); }
236 iterator end () { return instr_end(); }
237 const_iterator end () const { return instr_end(); }
238 reverse_iterator rbegin() { return instr_rbegin(); }
239 const_reverse_iterator rbegin() const { return instr_rbegin(); }
240 reverse_iterator rend () { return instr_rend(); }
241 const_reverse_iterator rend () const { return instr_rend(); }
243 inline iterator_range<iterator> terminators() {
244 return iterator_range<iterator>(getFirstTerminator(), end());
246 inline iterator_range<const_iterator> terminators() const {
247 return iterator_range<const_iterator>(getFirstTerminator(), end());
250 // Machine-CFG iterators
251 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
252 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
253 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
254 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
255 typedef std::vector<MachineBasicBlock *>::reverse_iterator
256 pred_reverse_iterator;
257 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
258 const_pred_reverse_iterator;
259 typedef std::vector<MachineBasicBlock *>::reverse_iterator
260 succ_reverse_iterator;
261 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
262 const_succ_reverse_iterator;
263 pred_iterator pred_begin() { return Predecessors.begin(); }
264 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
265 pred_iterator pred_end() { return Predecessors.end(); }
266 const_pred_iterator pred_end() const { return Predecessors.end(); }
267 pred_reverse_iterator pred_rbegin()
268 { return Predecessors.rbegin();}
269 const_pred_reverse_iterator pred_rbegin() const
270 { return Predecessors.rbegin();}
271 pred_reverse_iterator pred_rend()
272 { return Predecessors.rend(); }
273 const_pred_reverse_iterator pred_rend() const
274 { return Predecessors.rend(); }
275 unsigned pred_size() const {
276 return (unsigned)Predecessors.size();
278 bool pred_empty() const { return Predecessors.empty(); }
279 succ_iterator succ_begin() { return Successors.begin(); }
280 const_succ_iterator succ_begin() const { return Successors.begin(); }
281 succ_iterator succ_end() { return Successors.end(); }
282 const_succ_iterator succ_end() const { return Successors.end(); }
283 succ_reverse_iterator succ_rbegin()
284 { return Successors.rbegin(); }
285 const_succ_reverse_iterator succ_rbegin() const
286 { return Successors.rbegin(); }
287 succ_reverse_iterator succ_rend()
288 { return Successors.rend(); }
289 const_succ_reverse_iterator succ_rend() const
290 { return Successors.rend(); }
291 unsigned succ_size() const {
292 return (unsigned)Successors.size();
294 bool succ_empty() const { return Successors.empty(); }
296 inline iterator_range<pred_iterator> predecessors() {
297 return iterator_range<pred_iterator>(pred_begin(), pred_end());
299 inline iterator_range<const_pred_iterator> predecessors() const {
300 return iterator_range<const_pred_iterator>(pred_begin(), pred_end());
302 inline iterator_range<succ_iterator> successors() {
303 return iterator_range<succ_iterator>(succ_begin(), succ_end());
305 inline iterator_range<const_succ_iterator> successors() const {
306 return iterator_range<const_succ_iterator>(succ_begin(), succ_end());
309 // LiveIn management methods.
311 /// Adds the specified register as a live in. Note that it is an error to add
312 /// the same register to the same set more than once unless the intention is
313 /// to call sortUniqueLiveIns after all registers are added.
314 void addLiveIn(MCPhysReg PhysReg) { LiveIns.push_back(PhysReg); }
316 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do
317 /// this than repeatedly calling isLiveIn before calling addLiveIn for every
318 /// LiveIn insertion.
319 void sortUniqueLiveIns() {
320 std::sort(LiveIns.begin(), LiveIns.end());
321 LiveIns.erase(std::unique(LiveIns.begin(), LiveIns.end()), LiveIns.end());
324 /// Add PhysReg as live in to this block, and ensure that there is a copy of
325 /// PhysReg to a virtual register of class RC. Return the virtual register
326 /// that is a copy of the live in PhysReg.
327 unsigned addLiveIn(MCPhysReg PhysReg, const TargetRegisterClass *RC);
329 /// Remove the specified register from the live in set.
330 void removeLiveIn(MCPhysReg Reg);
332 /// Return true if the specified register is in the live in set.
333 bool isLiveIn(MCPhysReg Reg) const;
335 // Iteration support for live in sets. These sets are kept in sorted
336 // order by their register number.
337 typedef LiveInVector::const_iterator livein_iterator;
338 livein_iterator livein_begin() const { return LiveIns.begin(); }
339 livein_iterator livein_end() const { return LiveIns.end(); }
340 bool livein_empty() const { return LiveIns.empty(); }
341 iterator_range<livein_iterator> liveins() const {
342 return make_range(livein_begin(), livein_end());
345 /// Return alignment of the basic block. The alignment is specified as
347 unsigned getAlignment() const { return Alignment; }
349 /// Set alignment of the basic block. The alignment is specified as
351 void setAlignment(unsigned Align) { Alignment = Align; }
353 /// Returns true if the block is a landing pad. That is this basic block is
354 /// entered via an exception handler.
355 bool isLandingPad() const { return IsLandingPad; }
357 /// Indicates the block is a landing pad. That is this basic block is entered
358 /// via an exception handler.
359 void setIsLandingPad(bool V = true) { IsLandingPad = V; }
361 /// If this block has a successor that is a landing pad, return it. Otherwise
363 const MachineBasicBlock *getLandingPadSuccessor() const;
365 // Code Layout methods.
367 /// Move 'this' block before or after the specified block. This only moves
368 /// the block, it does not modify the CFG or adjust potential fall-throughs at
369 /// the end of the block.
370 void moveBefore(MachineBasicBlock *NewAfter);
371 void moveAfter(MachineBasicBlock *NewBefore);
373 /// Update the terminator instructions in block to account for changes to the
374 /// layout. If the block previously used a fallthrough, it may now need a
375 /// branch, and if it previously used branching it may now be able to use a
377 void updateTerminator();
379 // Machine-CFG mutators
381 /// Add succ as a successor of this MachineBasicBlock. The Predecessors list
382 /// of succ is automatically updated. WEIGHT parameter is stored in Weights
383 /// list and it may be used by MachineBranchProbabilityInfo analysis to
384 /// calculate branch probability.
386 /// Note that duplicate Machine CFG edges are not allowed.
387 void addSuccessor(MachineBasicBlock *succ, uint32_t weight = 0);
389 /// Set successor weight of a given iterator.
390 void setSuccWeight(succ_iterator I, uint32_t weight);
392 /// Remove successor from the successors list of this MachineBasicBlock. The
393 /// Predecessors list of succ is automatically updated.
394 void removeSuccessor(MachineBasicBlock *succ);
396 /// Remove specified successor from the successors list of this
397 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
398 /// Return the iterator to the element after the one removed.
399 succ_iterator removeSuccessor(succ_iterator I);
401 /// Replace successor OLD with NEW and update weight info.
402 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
404 /// Transfers all the successors from MBB to this machine basic block (i.e.,
405 /// copies all the successors fromMBB and remove all the successors from
407 void transferSuccessors(MachineBasicBlock *fromMBB);
409 /// Transfers all the successors, as in transferSuccessors, and update PHI
410 /// operands in the successor blocks which refer to fromMBB to refer to this.
411 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB);
413 /// Return true if any of the successors have weights attached to them.
414 bool hasSuccessorWeights() const { return !Weights.empty(); }
416 /// Return true if the specified MBB is a predecessor of this block.
417 bool isPredecessor(const MachineBasicBlock *MBB) const;
419 /// Return true if the specified MBB is a successor of this block.
420 bool isSuccessor(const MachineBasicBlock *MBB) const;
422 /// Return true if the specified MBB will be emitted immediately after this
423 /// block, such that if this block exits by falling through, control will
424 /// transfer to the specified MBB. Note that MBB need not be a successor at
425 /// all, for example if this block ends with an unconditional branch to some
427 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
429 /// Return true if the block can implicitly transfer control to the block
430 /// after it by falling off the end of it. This should return false if it can
431 /// reach the block after it, but it uses an explicit branch to do so (e.g., a
432 /// table jump). True is a conservative answer.
433 bool canFallThrough();
435 /// Returns a pointer to the first instruction in this block that is not a
436 /// PHINode instruction. When adding instructions to the beginning of the
437 /// basic block, they should be added before the returned value, not before
438 /// the first instruction, which might be PHI.
439 /// Returns end() is there's no non-PHI instruction.
440 iterator getFirstNonPHI();
442 /// Return the first instruction in MBB after I that is not a PHI or a label.
443 /// This is the correct point to insert copies at the beginning of a basic
445 iterator SkipPHIsAndLabels(iterator I);
447 /// Returns an iterator to the first terminator instruction of this basic
448 /// block. If a terminator does not exist, it returns end().
449 iterator getFirstTerminator();
450 const_iterator getFirstTerminator() const {
451 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
454 /// Same getFirstTerminator but it ignores bundles and return an
455 /// instr_iterator instead.
456 instr_iterator getFirstInstrTerminator();
458 /// Returns an iterator to the first non-debug instruction in the basic block,
460 iterator getFirstNonDebugInstr();
461 const_iterator getFirstNonDebugInstr() const {
462 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr();
465 /// Returns an iterator to the last non-debug instruction in the basic block,
467 iterator getLastNonDebugInstr();
468 const_iterator getLastNonDebugInstr() const {
469 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
472 /// Split the critical edge from this block to the given successor block, and
473 /// return the newly created block, or null if splitting is not possible.
475 /// This function updates LiveVariables, MachineDominatorTree, and
476 /// MachineLoopInfo, as applicable.
477 MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P);
479 void pop_front() { Insts.pop_front(); }
480 void pop_back() { Insts.pop_back(); }
481 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
483 /// Insert MI into the instruction list before I, possibly inside a bundle.
485 /// If the insertion point is inside a bundle, MI will be added to the bundle,
486 /// otherwise MI will not be added to any bundle. That means this function
487 /// alone can't be used to prepend or append instructions to bundles. See
488 /// MIBundleBuilder::insert() for a more reliable way of doing that.
489 instr_iterator insert(instr_iterator I, MachineInstr *M);
491 /// Insert a range of instructions into the instruction list before I.
492 template<typename IT>
493 void insert(iterator I, IT S, IT E) {
494 assert((I == end() || I->getParent() == this) &&
495 "iterator points outside of basic block");
496 Insts.insert(I.getInstrIterator(), S, E);
499 /// Insert MI into the instruction list before I.
500 iterator insert(iterator I, MachineInstr *MI) {
501 assert((I == end() || I->getParent() == this) &&
502 "iterator points outside of basic block");
503 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
504 "Cannot insert instruction with bundle flags");
505 return Insts.insert(I.getInstrIterator(), MI);
508 /// Insert MI into the instruction list after I.
509 iterator insertAfter(iterator I, MachineInstr *MI) {
510 assert((I == end() || I->getParent() == this) &&
511 "iterator points outside of basic block");
512 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
513 "Cannot insert instruction with bundle flags");
514 return Insts.insertAfter(I.getInstrIterator(), MI);
517 /// Remove an instruction from the instruction list and delete it.
519 /// If the instruction is part of a bundle, the other instructions in the
520 /// bundle will still be bundled after removing the single instruction.
521 instr_iterator erase(instr_iterator I);
523 /// Remove an instruction from the instruction list and delete it.
525 /// If the instruction is part of a bundle, the other instructions in the
526 /// bundle will still be bundled after removing the single instruction.
527 instr_iterator erase_instr(MachineInstr *I) {
528 return erase(instr_iterator(I));
531 /// Remove a range of instructions from the instruction list and delete them.
532 iterator erase(iterator I, iterator E) {
533 return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
536 /// Remove an instruction or bundle from the instruction list and delete it.
538 /// If I points to a bundle of instructions, they are all erased.
539 iterator erase(iterator I) {
540 return erase(I, std::next(I));
543 /// Remove an instruction from the instruction list and delete it.
545 /// If I is the head of a bundle of instructions, the whole bundle will be
547 iterator erase(MachineInstr *I) {
548 return erase(iterator(I));
551 /// Remove the unbundled instruction from the instruction list without
554 /// This function can not be used to remove bundled instructions, use
555 /// remove_instr to remove individual instructions from a bundle.
556 MachineInstr *remove(MachineInstr *I) {
557 assert(!I->isBundled() && "Cannot remove bundled instructions");
558 return Insts.remove(I);
561 /// Remove the possibly bundled instruction from the instruction list
562 /// without deleting it.
564 /// If the instruction is part of a bundle, the other instructions in the
565 /// bundle will still be bundled after removing the single instruction.
566 MachineInstr *remove_instr(MachineInstr *I);
572 /// Take an instruction from MBB 'Other' at the position From, and insert it
573 /// into this MBB right before 'Where'.
575 /// If From points to a bundle of instructions, the whole bundle is moved.
576 void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
577 // The range splice() doesn't allow noop moves, but this one does.
579 splice(Where, Other, From, std::next(From));
582 /// Take a block of instructions from MBB 'Other' in the range [From, To),
583 /// and insert them into this MBB right before 'Where'.
585 /// The instruction at 'Where' must not be included in the range of
586 /// instructions to move.
587 void splice(iterator Where, MachineBasicBlock *Other,
588 iterator From, iterator To) {
589 Insts.splice(Where.getInstrIterator(), Other->Insts,
590 From.getInstrIterator(), To.getInstrIterator());
593 /// This method unlinks 'this' from the containing function, and returns it,
594 /// but does not delete it.
595 MachineBasicBlock *removeFromParent();
597 /// This method unlinks 'this' from the containing function and deletes it.
598 void eraseFromParent();
600 /// Given a machine basic block that branched to 'Old', change the code and
601 /// CFG so that it branches to 'New' instead.
602 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
604 /// Various pieces of code can cause excess edges in the CFG to be inserted.
605 /// If we have proven that MBB can only branch to DestA and DestB, remove any
606 /// other MBB successors from the CFG. DestA and DestB can be null. Besides
607 /// DestA and DestB, retain other edges leading to LandingPads (currently
608 /// there can be only one; we don't check or require that here). Note it is
609 /// possible that DestA and/or DestB are LandingPads.
610 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
611 MachineBasicBlock *DestB,
614 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE
615 /// instructions. Return UnknownLoc if there is none.
616 DebugLoc findDebugLoc(instr_iterator MBBI);
617 DebugLoc findDebugLoc(iterator MBBI) {
618 return findDebugLoc(MBBI.getInstrIterator());
621 /// Possible outcome of a register liveness query to computeRegisterLiveness()
622 enum LivenessQueryResult {
623 LQR_Live, ///< Register is known to be live.
624 LQR_OverlappingLive, ///< Register itself is not live, but some overlapping
626 LQR_Dead, ///< Register is known to be dead.
627 LQR_Unknown ///< Register liveness not decidable from local
631 /// Return whether (physical) register \p Reg has been <def>ined and not
632 /// <kill>ed as of just before \p Before.
634 /// Search is localised to a neighborhood of \p Neighborhood instructions
635 /// before (searching for defs or kills) and \p Neighborhood instructions
636 /// after (searching just for defs) \p Before.
638 /// \p Reg must be a physical register.
639 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
641 const_iterator Before,
642 unsigned Neighborhood=10) const;
644 // Debugging methods.
646 void print(raw_ostream &OS, SlotIndexes* = nullptr) const;
647 void print(raw_ostream &OS, ModuleSlotTracker &MST,
648 SlotIndexes * = nullptr) const;
650 // Printing method used by LoopInfo.
651 void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
653 /// MachineBasicBlocks are uniquely numbered at the function level, unless
654 /// they're not in a MachineFunction yet, in which case this will return -1.
655 int getNumber() const { return Number; }
656 void setNumber(int N) { Number = N; }
658 /// Return the MCSymbol for this basic block.
659 MCSymbol *getSymbol() const;
663 /// Return weight iterator corresponding to the I successor iterator.
664 weight_iterator getWeightIterator(succ_iterator I);
665 const_weight_iterator getWeightIterator(const_succ_iterator I) const;
667 friend class MachineBranchProbabilityInfo;
668 friend class MIPrinter;
670 /// Return weight of the edge from this block to MBB. This method should NOT
671 /// be called directly, but by using getEdgeWeight method from
672 /// MachineBranchProbabilityInfo class.
673 uint32_t getSuccWeight(const_succ_iterator Succ) const;
676 // Methods used to maintain doubly linked list of blocks...
677 friend struct ilist_traits<MachineBasicBlock>;
679 // Machine-CFG mutators
681 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
682 /// unless you know what you're doing, because it doesn't update pred's
683 /// successors list. Use pred->addSuccessor instead.
684 void addPredecessor(MachineBasicBlock *pred);
686 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
687 /// unless you know what you're doing, because it doesn't update pred's
688 /// successors list. Use pred->removeSuccessor instead.
689 void removePredecessor(MachineBasicBlock *pred);
692 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
694 // This is useful when building IndexedMaps keyed on basic block pointers.
695 struct MBB2NumberFunctor :
696 public std::unary_function<const MachineBasicBlock*, unsigned> {
697 unsigned operator()(const MachineBasicBlock *MBB) const {
698 return MBB->getNumber();
702 //===--------------------------------------------------------------------===//
703 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
704 //===--------------------------------------------------------------------===//
706 // Provide specializations of GraphTraits to be able to treat a
707 // MachineFunction as a graph of MachineBasicBlocks.
710 template <> struct GraphTraits<MachineBasicBlock *> {
711 typedef MachineBasicBlock NodeType;
712 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
714 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
715 static inline ChildIteratorType child_begin(NodeType *N) {
716 return N->succ_begin();
718 static inline ChildIteratorType child_end(NodeType *N) {
719 return N->succ_end();
723 template <> struct GraphTraits<const MachineBasicBlock *> {
724 typedef const MachineBasicBlock NodeType;
725 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
727 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
728 static inline ChildIteratorType child_begin(NodeType *N) {
729 return N->succ_begin();
731 static inline ChildIteratorType child_end(NodeType *N) {
732 return N->succ_end();
736 // Provide specializations of GraphTraits to be able to treat a
737 // MachineFunction as a graph of MachineBasicBlocks and to walk it
738 // in inverse order. Inverse order for a function is considered
739 // to be when traversing the predecessor edges of a MBB
740 // instead of the successor edges.
742 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
743 typedef MachineBasicBlock NodeType;
744 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
745 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
748 static inline ChildIteratorType child_begin(NodeType *N) {
749 return N->pred_begin();
751 static inline ChildIteratorType child_end(NodeType *N) {
752 return N->pred_end();
756 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
757 typedef const MachineBasicBlock NodeType;
758 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
759 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
762 static inline ChildIteratorType child_begin(NodeType *N) {
763 return N->pred_begin();
765 static inline ChildIteratorType child_end(NodeType *N) {
766 return N->pred_end();
772 /// MachineInstrSpan provides an interface to get an iteration range
773 /// containing the instruction it was initialized with, along with all
774 /// those instructions inserted prior to or following that instruction
775 /// at some point after the MachineInstrSpan is constructed.
776 class MachineInstrSpan {
777 MachineBasicBlock &MBB;
778 MachineBasicBlock::iterator I, B, E;
780 MachineInstrSpan(MachineBasicBlock::iterator I)
781 : MBB(*I->getParent()),
783 B(I == MBB.begin() ? MBB.end() : std::prev(I)),
786 MachineBasicBlock::iterator begin() {
787 return B == MBB.end() ? MBB.begin() : std::next(B);
789 MachineBasicBlock::iterator end() { return E; }
790 bool empty() { return begin() == end(); }
792 MachineBasicBlock::iterator getInitial() { return I; }
795 } // End llvm namespace