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;
68 MachineFunction *xParent;
70 /// Keep track of the predecessor / successor basic blocks.
71 std::vector<MachineBasicBlock *> Predecessors;
72 std::vector<MachineBasicBlock *> Successors;
74 /// Keep track of the weights to the successors. This vector has the same
75 /// order as Successors, or it is empty if we don't use it (disable
77 std::vector<uint32_t> Weights;
78 typedef std::vector<uint32_t>::iterator weight_iterator;
79 typedef std::vector<uint32_t>::const_iterator const_weight_iterator;
81 /// Keep track of the physical registers that are livein of the basicblock.
82 std::vector<unsigned> LiveIns;
84 /// Alignment of the basic block. Zero if the basic block does not need to be
85 /// aligned. The alignment is specified as log2(bytes).
88 /// Indicate that this basic block is entered via an exception handler.
91 /// Indicate that this basic block is potentially the target of an indirect
95 /// \brief since getSymbol is a relatively heavy-weight operation, the symbol
96 /// is only computed once and is cached.
97 mutable MCSymbol *CachedMCSymbol;
99 // Intrusive list support
100 MachineBasicBlock() {}
102 explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
104 ~MachineBasicBlock();
106 // MachineBasicBlocks are allocated and owned by MachineFunction.
107 friend class MachineFunction;
110 /// Return the LLVM basic block that this instance corresponded to originally.
111 /// Note that this may be NULL if this instance does not correspond directly
112 /// to an LLVM basic block.
113 const BasicBlock *getBasicBlock() const { return BB; }
115 /// Return the name of the corresponding LLVM basic block, or "(null)".
116 StringRef getName() const;
118 /// Return a formatted string to identify this block and its parent function.
119 std::string getFullName() const;
121 /// Test whether this block is potentially the target of an indirect branch.
122 bool hasAddressTaken() const { return AddressTaken; }
124 /// Set this block to reflect that it potentially is the target of an indirect
126 void setHasAddressTaken() { AddressTaken = true; }
128 /// Return the MachineFunction containing this basic block.
129 const MachineFunction *getParent() const { return xParent; }
130 MachineFunction *getParent() { return xParent; }
132 /// MachineBasicBlock iterator that automatically skips over MIs that are
133 /// inside bundles (i.e. walk top level MIs only).
134 template<typename Ty, typename IterTy>
135 class bundle_iterator
136 : public std::iterator<std::bidirectional_iterator_tag, Ty, ptrdiff_t> {
140 bundle_iterator(IterTy mii) : MII(mii) {}
142 bundle_iterator(Ty &mi) : MII(mi) {
143 assert(!mi.isBundledWithPred() &&
144 "It's not legal to initialize bundle_iterator with a bundled MI");
146 bundle_iterator(Ty *mi) : MII(mi) {
147 assert((!mi || !mi->isBundledWithPred()) &&
148 "It's not legal to initialize bundle_iterator with a bundled MI");
150 // Template allows conversion from const to nonconst.
151 template<class OtherTy, class OtherIterTy>
152 bundle_iterator(const bundle_iterator<OtherTy, OtherIterTy> &I)
153 : MII(I.getInstrIterator()) {}
154 bundle_iterator() : MII(nullptr) {}
156 Ty &operator*() const { return *MII; }
157 Ty *operator->() const { return &operator*(); }
159 operator Ty*() const { return MII; }
161 bool operator==(const bundle_iterator &x) const {
164 bool operator!=(const bundle_iterator &x) const {
165 return !operator==(x);
168 // Increment and decrement operators...
169 bundle_iterator &operator--() { // predecrement - Back up
171 while (MII->isBundledWithPred());
174 bundle_iterator &operator++() { // preincrement - Advance
175 while (MII->isBundledWithSucc())
180 bundle_iterator operator--(int) { // postdecrement operators...
181 bundle_iterator tmp = *this;
185 bundle_iterator operator++(int) { // postincrement operators...
186 bundle_iterator tmp = *this;
191 IterTy getInstrIterator() const {
196 typedef Instructions::iterator instr_iterator;
197 typedef Instructions::const_iterator const_instr_iterator;
198 typedef std::reverse_iterator<instr_iterator> reverse_instr_iterator;
200 std::reverse_iterator<const_instr_iterator> const_reverse_instr_iterator;
203 bundle_iterator<MachineInstr,instr_iterator> iterator;
205 bundle_iterator<const MachineInstr,const_instr_iterator> const_iterator;
206 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
207 typedef std::reverse_iterator<iterator> reverse_iterator;
210 unsigned size() const { return (unsigned)Insts.size(); }
211 bool empty() const { return Insts.empty(); }
213 MachineInstr &instr_front() { return Insts.front(); }
214 MachineInstr &instr_back() { return Insts.back(); }
215 const MachineInstr &instr_front() const { return Insts.front(); }
216 const MachineInstr &instr_back() const { return Insts.back(); }
218 MachineInstr &front() { return Insts.front(); }
219 MachineInstr &back() { return *--end(); }
220 const MachineInstr &front() const { return Insts.front(); }
221 const MachineInstr &back() const { return *--end(); }
223 instr_iterator instr_begin() { return Insts.begin(); }
224 const_instr_iterator instr_begin() const { return Insts.begin(); }
225 instr_iterator instr_end() { return Insts.end(); }
226 const_instr_iterator instr_end() const { return Insts.end(); }
227 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
228 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
229 reverse_instr_iterator instr_rend () { return Insts.rend(); }
230 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
232 iterator begin() { return instr_begin(); }
233 const_iterator begin() const { return instr_begin(); }
234 iterator end () { return instr_end(); }
235 const_iterator end () const { return instr_end(); }
236 reverse_iterator rbegin() { return instr_rbegin(); }
237 const_reverse_iterator rbegin() const { return instr_rbegin(); }
238 reverse_iterator rend () { return instr_rend(); }
239 const_reverse_iterator rend () const { return instr_rend(); }
241 inline iterator_range<iterator> terminators() {
242 return iterator_range<iterator>(getFirstTerminator(), end());
244 inline iterator_range<const_iterator> terminators() const {
245 return iterator_range<const_iterator>(getFirstTerminator(), end());
248 // Machine-CFG iterators
249 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
250 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
251 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
252 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
253 typedef std::vector<MachineBasicBlock *>::reverse_iterator
254 pred_reverse_iterator;
255 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
256 const_pred_reverse_iterator;
257 typedef std::vector<MachineBasicBlock *>::reverse_iterator
258 succ_reverse_iterator;
259 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
260 const_succ_reverse_iterator;
261 pred_iterator pred_begin() { return Predecessors.begin(); }
262 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
263 pred_iterator pred_end() { return Predecessors.end(); }
264 const_pred_iterator pred_end() const { return Predecessors.end(); }
265 pred_reverse_iterator pred_rbegin()
266 { return Predecessors.rbegin();}
267 const_pred_reverse_iterator pred_rbegin() const
268 { return Predecessors.rbegin();}
269 pred_reverse_iterator pred_rend()
270 { return Predecessors.rend(); }
271 const_pred_reverse_iterator pred_rend() const
272 { return Predecessors.rend(); }
273 unsigned pred_size() const {
274 return (unsigned)Predecessors.size();
276 bool pred_empty() const { return Predecessors.empty(); }
277 succ_iterator succ_begin() { return Successors.begin(); }
278 const_succ_iterator succ_begin() const { return Successors.begin(); }
279 succ_iterator succ_end() { return Successors.end(); }
280 const_succ_iterator succ_end() const { return Successors.end(); }
281 succ_reverse_iterator succ_rbegin()
282 { return Successors.rbegin(); }
283 const_succ_reverse_iterator succ_rbegin() const
284 { return Successors.rbegin(); }
285 succ_reverse_iterator succ_rend()
286 { return Successors.rend(); }
287 const_succ_reverse_iterator succ_rend() const
288 { return Successors.rend(); }
289 unsigned succ_size() const {
290 return (unsigned)Successors.size();
292 bool succ_empty() const { return Successors.empty(); }
294 inline iterator_range<pred_iterator> predecessors() {
295 return iterator_range<pred_iterator>(pred_begin(), pred_end());
297 inline iterator_range<const_pred_iterator> predecessors() const {
298 return iterator_range<const_pred_iterator>(pred_begin(), pred_end());
300 inline iterator_range<succ_iterator> successors() {
301 return iterator_range<succ_iterator>(succ_begin(), succ_end());
303 inline iterator_range<const_succ_iterator> successors() const {
304 return iterator_range<const_succ_iterator>(succ_begin(), succ_end());
307 // LiveIn management methods.
309 /// Adds the specified register as a live in. Note that it is an error to add
310 /// the same register to the same set more than once unless the intention is
311 /// to call sortUniqueLiveIns after all registers are added.
312 void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
314 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do
315 /// this than repeatedly calling isLiveIn before calling addLiveIn for every
316 /// LiveIn insertion.
317 void sortUniqueLiveIns() {
318 std::sort(LiveIns.begin(), LiveIns.end());
319 LiveIns.erase(std::unique(LiveIns.begin(), LiveIns.end()), LiveIns.end());
322 /// Add PhysReg as live in to this block, and ensure that there is a copy of
323 /// PhysReg to a virtual register of class RC. Return the virtual register
324 /// that is a copy of the live in PhysReg.
325 unsigned addLiveIn(unsigned PhysReg, const TargetRegisterClass *RC);
327 /// Remove the specified register from the live in set.
328 void removeLiveIn(unsigned Reg);
330 /// Return true if the specified register is in the live in set.
331 bool isLiveIn(unsigned Reg) const;
333 // Iteration support for live in sets. These sets are kept in sorted
334 // order by their register number.
335 typedef std::vector<unsigned>::const_iterator livein_iterator;
336 livein_iterator livein_begin() const { return LiveIns.begin(); }
337 livein_iterator livein_end() const { return LiveIns.end(); }
338 bool livein_empty() const { return LiveIns.empty(); }
339 iterator_range<livein_iterator> liveins() const {
340 return make_range(livein_begin(), livein_end());
343 /// Return alignment of the basic block. The alignment is specified as
345 unsigned getAlignment() const { return Alignment; }
347 /// Set alignment of the basic block. The alignment is specified as
349 void setAlignment(unsigned Align) { Alignment = Align; }
351 /// Returns true if the block is a landing pad. That is this basic block is
352 /// entered via an exception handler.
353 bool isLandingPad() const { return IsLandingPad; }
355 /// Indicates the block is a landing pad. That is this basic block is entered
356 /// via an exception handler.
357 void setIsLandingPad(bool V = true) { IsLandingPad = V; }
359 /// If this block has a successor that is a landing pad, return it. Otherwise
361 const MachineBasicBlock *getLandingPadSuccessor() const;
363 // Code Layout methods.
365 /// Move 'this' block before or after the specified block. This only moves
366 /// the block, it does not modify the CFG or adjust potential fall-throughs at
367 /// the end of the block.
368 void moveBefore(MachineBasicBlock *NewAfter);
369 void moveAfter(MachineBasicBlock *NewBefore);
371 /// Update the terminator instructions in block to account for changes to the
372 /// layout. If the block previously used a fallthrough, it may now need a
373 /// branch, and if it previously used branching it may now be able to use a
375 void updateTerminator();
377 // Machine-CFG mutators
379 /// Add succ as a successor of this MachineBasicBlock. The Predecessors list
380 /// of succ is automatically updated. WEIGHT parameter is stored in Weights
381 /// list and it may be used by MachineBranchProbabilityInfo analysis to
382 /// calculate branch probability.
384 /// Note that duplicate Machine CFG edges are not allowed.
385 void addSuccessor(MachineBasicBlock *succ, uint32_t weight = 0);
387 /// Set successor weight of a given iterator.
388 void setSuccWeight(succ_iterator I, uint32_t weight);
390 /// Remove successor from the successors list of this MachineBasicBlock. The
391 /// Predecessors list of succ is automatically updated.
392 void removeSuccessor(MachineBasicBlock *succ);
394 /// Remove specified successor from the successors list of this
395 /// MachineBasicBlock. The Predecessors list of succ is automatically updated.
396 /// Return the iterator to the element after the one removed.
397 succ_iterator removeSuccessor(succ_iterator I);
399 /// Replace successor OLD with NEW and update weight info.
400 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
402 /// Transfers all the successors from MBB to this machine basic block (i.e.,
403 /// copies all the successors fromMBB and remove all the successors from
405 void transferSuccessors(MachineBasicBlock *fromMBB);
407 /// Transfers all the successors, as in transferSuccessors, and update PHI
408 /// operands in the successor blocks which refer to fromMBB to refer to this.
409 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *fromMBB);
411 /// Return true if any of the successors have weights attached to them.
412 bool hasSuccessorWeights() const { return !Weights.empty(); }
414 /// Return true if the specified MBB is a predecessor of this block.
415 bool isPredecessor(const MachineBasicBlock *MBB) const;
417 /// Return true if the specified MBB is a successor of this block.
418 bool isSuccessor(const MachineBasicBlock *MBB) const;
420 /// Return true if the specified MBB will be emitted immediately after this
421 /// block, such that if this block exits by falling through, control will
422 /// transfer to the specified MBB. Note that MBB need not be a successor at
423 /// all, for example if this block ends with an unconditional branch to some
425 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
427 /// Return true if the block can implicitly transfer control to the block
428 /// after it by falling off the end of it. This should return false if it can
429 /// reach the block after it, but it uses an explicit branch to do so (e.g., a
430 /// table jump). True is a conservative answer.
431 bool canFallThrough();
433 /// Returns a pointer to the first instruction in this block that is not a
434 /// PHINode instruction. When adding instructions to the beginning of the
435 /// basic block, they should be added before the returned value, not before
436 /// the first instruction, which might be PHI.
437 /// Returns end() is there's no non-PHI instruction.
438 iterator getFirstNonPHI();
440 /// Return the first instruction in MBB after I that is not a PHI or a label.
441 /// This is the correct point to insert copies at the beginning of a basic
443 iterator SkipPHIsAndLabels(iterator I);
445 /// Returns an iterator to the first terminator instruction of this basic
446 /// block. If a terminator does not exist, it returns end().
447 iterator getFirstTerminator();
448 const_iterator getFirstTerminator() const {
449 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
452 /// Same getFirstTerminator but it ignores bundles and return an
453 /// instr_iterator instead.
454 instr_iterator getFirstInstrTerminator();
456 /// Returns an iterator to the first non-debug instruction in the basic block,
458 iterator getFirstNonDebugInstr();
459 const_iterator getFirstNonDebugInstr() const {
460 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr();
463 /// Returns an iterator to the last non-debug instruction in the basic block,
465 iterator getLastNonDebugInstr();
466 const_iterator getLastNonDebugInstr() const {
467 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
470 /// Split the critical edge from this block to the given successor block, and
471 /// return the newly created block, or null if splitting is not possible.
473 /// This function updates LiveVariables, MachineDominatorTree, and
474 /// MachineLoopInfo, as applicable.
475 MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P);
477 void pop_front() { Insts.pop_front(); }
478 void pop_back() { Insts.pop_back(); }
479 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
481 /// Insert MI into the instruction list before I, possibly inside a bundle.
483 /// If the insertion point is inside a bundle, MI will be added to the bundle,
484 /// otherwise MI will not be added to any bundle. That means this function
485 /// alone can't be used to prepend or append instructions to bundles. See
486 /// MIBundleBuilder::insert() for a more reliable way of doing that.
487 instr_iterator insert(instr_iterator I, MachineInstr *M);
489 /// Insert a range of instructions into the instruction list before I.
490 template<typename IT>
491 void insert(iterator I, IT S, IT E) {
492 assert((I == end() || I->getParent() == this) &&
493 "iterator points outside of basic block");
494 Insts.insert(I.getInstrIterator(), S, E);
497 /// Insert MI into the instruction list before I.
498 iterator insert(iterator I, MachineInstr *MI) {
499 assert((I == end() || I->getParent() == this) &&
500 "iterator points outside of basic block");
501 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
502 "Cannot insert instruction with bundle flags");
503 return Insts.insert(I.getInstrIterator(), MI);
506 /// Insert MI into the instruction list after I.
507 iterator insertAfter(iterator I, MachineInstr *MI) {
508 assert((I == end() || I->getParent() == this) &&
509 "iterator points outside of basic block");
510 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
511 "Cannot insert instruction with bundle flags");
512 return Insts.insertAfter(I.getInstrIterator(), MI);
515 /// Remove an instruction from the instruction list and delete it.
517 /// If the instruction is part of a bundle, the other instructions in the
518 /// bundle will still be bundled after removing the single instruction.
519 instr_iterator erase(instr_iterator I);
521 /// Remove an instruction from the instruction list and delete it.
523 /// If the instruction is part of a bundle, the other instructions in the
524 /// bundle will still be bundled after removing the single instruction.
525 instr_iterator erase_instr(MachineInstr *I) {
526 return erase(instr_iterator(I));
529 /// Remove a range of instructions from the instruction list and delete them.
530 iterator erase(iterator I, iterator E) {
531 return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
534 /// Remove an instruction or bundle from the instruction list and delete it.
536 /// If I points to a bundle of instructions, they are all erased.
537 iterator erase(iterator I) {
538 return erase(I, std::next(I));
541 /// Remove an instruction from the instruction list and delete it.
543 /// If I is the head of a bundle of instructions, the whole bundle will be
545 iterator erase(MachineInstr *I) {
546 return erase(iterator(I));
549 /// Remove the unbundled instruction from the instruction list without
552 /// This function can not be used to remove bundled instructions, use
553 /// remove_instr to remove individual instructions from a bundle.
554 MachineInstr *remove(MachineInstr *I) {
555 assert(!I->isBundled() && "Cannot remove bundled instructions");
556 return Insts.remove(I);
559 /// Remove the possibly bundled instruction from the instruction list
560 /// without deleting it.
562 /// If the instruction is part of a bundle, the other instructions in the
563 /// bundle will still be bundled after removing the single instruction.
564 MachineInstr *remove_instr(MachineInstr *I);
570 /// Take an instruction from MBB 'Other' at the position From, and insert it
571 /// into this MBB right before 'Where'.
573 /// If From points to a bundle of instructions, the whole bundle is moved.
574 void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
575 // The range splice() doesn't allow noop moves, but this one does.
577 splice(Where, Other, From, std::next(From));
580 /// Take a block of instructions from MBB 'Other' in the range [From, To),
581 /// and insert them into this MBB right before 'Where'.
583 /// The instruction at 'Where' must not be included in the range of
584 /// instructions to move.
585 void splice(iterator Where, MachineBasicBlock *Other,
586 iterator From, iterator To) {
587 Insts.splice(Where.getInstrIterator(), Other->Insts,
588 From.getInstrIterator(), To.getInstrIterator());
591 /// This method unlinks 'this' from the containing function, and returns it,
592 /// but does not delete it.
593 MachineBasicBlock *removeFromParent();
595 /// This method unlinks 'this' from the containing function and deletes it.
596 void eraseFromParent();
598 /// Given a machine basic block that branched to 'Old', change the code and
599 /// CFG so that it branches to 'New' instead.
600 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
602 /// Various pieces of code can cause excess edges in the CFG to be inserted.
603 /// If we have proven that MBB can only branch to DestA and DestB, remove any
604 /// other MBB successors from the CFG. DestA and DestB can be null. Besides
605 /// DestA and DestB, retain other edges leading to LandingPads (currently
606 /// there can be only one; we don't check or require that here). Note it is
607 /// possible that DestA and/or DestB are LandingPads.
608 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
609 MachineBasicBlock *DestB,
612 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE
613 /// instructions. Return UnknownLoc if there is none.
614 DebugLoc findDebugLoc(instr_iterator MBBI);
615 DebugLoc findDebugLoc(iterator MBBI) {
616 return findDebugLoc(MBBI.getInstrIterator());
619 /// Possible outcome of a register liveness query to computeRegisterLiveness()
620 enum LivenessQueryResult {
621 LQR_Live, ///< Register is known to be live.
622 LQR_OverlappingLive, ///< Register itself is not live, but some overlapping
624 LQR_Dead, ///< Register is known to be dead.
625 LQR_Unknown ///< Register liveness not decidable from local
629 /// Return whether (physical) register \p Reg has been <def>ined and not
630 /// <kill>ed as of just before \p Before.
632 /// Search is localised to a neighborhood of \p Neighborhood instructions
633 /// before (searching for defs or kills) and \p Neighborhood instructions
634 /// after (searching just for defs) \p Before.
636 /// \p Reg must be a physical register.
637 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
639 const_iterator Before,
640 unsigned Neighborhood=10) const;
642 // Debugging methods.
644 void print(raw_ostream &OS, SlotIndexes* = nullptr) const;
645 void print(raw_ostream &OS, ModuleSlotTracker &MST,
646 SlotIndexes * = nullptr) const;
648 // Printing method used by LoopInfo.
649 void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
651 /// MachineBasicBlocks are uniquely numbered at the function level, unless
652 /// they're not in a MachineFunction yet, in which case this will return -1.
653 int getNumber() const { return Number; }
654 void setNumber(int N) { Number = N; }
656 /// Return the MCSymbol for this basic block.
657 MCSymbol *getSymbol() const;
661 /// Return weight iterator corresponding to the I successor iterator.
662 weight_iterator getWeightIterator(succ_iterator I);
663 const_weight_iterator getWeightIterator(const_succ_iterator I) const;
665 friend class MachineBranchProbabilityInfo;
666 friend class MIPrinter;
668 /// Return weight of the edge from this block to MBB. This method should NOT
669 /// be called directly, but by using getEdgeWeight method from
670 /// MachineBranchProbabilityInfo class.
671 uint32_t getSuccWeight(const_succ_iterator Succ) const;
674 // Methods used to maintain doubly linked list of blocks...
675 friend struct ilist_traits<MachineBasicBlock>;
677 // Machine-CFG mutators
679 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
680 /// unless you know what you're doing, because it doesn't update pred's
681 /// successors list. Use pred->addSuccessor instead.
682 void addPredecessor(MachineBasicBlock *pred);
684 /// Remove pred as a predecessor of this MachineBasicBlock. Don't do this
685 /// unless you know what you're doing, because it doesn't update pred's
686 /// successors list. Use pred->removeSuccessor instead.
687 void removePredecessor(MachineBasicBlock *pred);
690 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
692 // This is useful when building IndexedMaps keyed on basic block pointers.
693 struct MBB2NumberFunctor :
694 public std::unary_function<const MachineBasicBlock*, unsigned> {
695 unsigned operator()(const MachineBasicBlock *MBB) const {
696 return MBB->getNumber();
700 //===--------------------------------------------------------------------===//
701 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
702 //===--------------------------------------------------------------------===//
704 // Provide specializations of GraphTraits to be able to treat a
705 // MachineFunction as a graph of MachineBasicBlocks.
708 template <> struct GraphTraits<MachineBasicBlock *> {
709 typedef MachineBasicBlock NodeType;
710 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
712 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
713 static inline ChildIteratorType child_begin(NodeType *N) {
714 return N->succ_begin();
716 static inline ChildIteratorType child_end(NodeType *N) {
717 return N->succ_end();
721 template <> struct GraphTraits<const MachineBasicBlock *> {
722 typedef const MachineBasicBlock NodeType;
723 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
725 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
726 static inline ChildIteratorType child_begin(NodeType *N) {
727 return N->succ_begin();
729 static inline ChildIteratorType child_end(NodeType *N) {
730 return N->succ_end();
734 // Provide specializations of GraphTraits to be able to treat a
735 // MachineFunction as a graph of MachineBasicBlocks and to walk it
736 // in inverse order. Inverse order for a function is considered
737 // to be when traversing the predecessor edges of a MBB
738 // instead of the successor edges.
740 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
741 typedef MachineBasicBlock NodeType;
742 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
743 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
746 static inline ChildIteratorType child_begin(NodeType *N) {
747 return N->pred_begin();
749 static inline ChildIteratorType child_end(NodeType *N) {
750 return N->pred_end();
754 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
755 typedef const MachineBasicBlock NodeType;
756 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
757 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
760 static inline ChildIteratorType child_begin(NodeType *N) {
761 return N->pred_begin();
763 static inline ChildIteratorType child_end(NodeType *N) {
764 return N->pred_end();
770 /// MachineInstrSpan provides an interface to get an iteration range
771 /// containing the instruction it was initialized with, along with all
772 /// those instructions inserted prior to or following that instruction
773 /// at some point after the MachineInstrSpan is constructed.
774 class MachineInstrSpan {
775 MachineBasicBlock &MBB;
776 MachineBasicBlock::iterator I, B, E;
778 MachineInstrSpan(MachineBasicBlock::iterator I)
779 : MBB(*I->getParent()),
781 B(I == MBB.begin() ? MBB.end() : std::prev(I)),
784 MachineBasicBlock::iterator begin() {
785 return B == MBB.end() ? MBB.begin() : std::next(B);
787 MachineBasicBlock::iterator end() { return E; }
788 bool empty() { return begin() == end(); }
790 MachineBasicBlock::iterator getInitial() { return I; }
793 } // End llvm namespace