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/BranchProbability.h"
20 #include "llvm/MC/MCRegisterInfo.h"
21 #include "llvm/Support/DataTypes.h"
28 class MachineFunction;
34 class MachineBranchProbabilityInfo;
36 // Forward declaration to avoid circular include problem with TargetRegisterInfo
37 typedef unsigned LaneBitmask;
40 struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
42 mutable ilist_half_node<MachineInstr> Sentinel;
44 // this is only set by the MachineBasicBlock owning the LiveList
45 friend class MachineBasicBlock;
46 MachineBasicBlock* Parent;
49 MachineInstr *createSentinel() const {
50 return static_cast<MachineInstr*>(&Sentinel);
52 void destroySentinel(MachineInstr *) const {}
54 MachineInstr *provideInitialHead() const { return createSentinel(); }
55 MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); }
56 static void noteHead(MachineInstr*, MachineInstr*) {}
58 void addNodeToList(MachineInstr* N);
59 void removeNodeFromList(MachineInstr* N);
60 void transferNodesFromList(ilist_traits &SrcTraits,
61 ilist_iterator<MachineInstr> First,
62 ilist_iterator<MachineInstr> Last);
63 void deleteNode(MachineInstr *N);
65 void createNode(const MachineInstr &);
68 class MachineBasicBlock
69 : public ilist_node_with_parent<MachineBasicBlock, MachineFunction> {
71 /// Pair of physical register and lane mask.
72 /// This is not simply a std::pair typedef because the members should be named
73 /// clearly as they both have an integer type.
74 struct RegisterMaskPair {
79 RegisterMaskPair(MCPhysReg PhysReg, LaneBitmask LaneMask)
80 : PhysReg(PhysReg), LaneMask(LaneMask) {}
84 typedef ilist<MachineInstr> Instructions;
88 MachineFunction *xParent;
90 /// Keep track of the predecessor / successor basic blocks.
91 std::vector<MachineBasicBlock *> Predecessors;
92 std::vector<MachineBasicBlock *> Successors;
94 /// Keep track of the weights to the successors. This vector has the same
95 /// order as Successors, or it is empty if we don't use it (disable
97 std::vector<uint32_t> Weights;
98 typedef std::vector<uint32_t>::iterator weight_iterator;
99 typedef std::vector<uint32_t>::const_iterator const_weight_iterator;
101 /// Keep track of the probabilities to the successors. This vector has the
102 /// same order as Successors, or it is empty if we don't use it (disable
104 std::vector<BranchProbability> Probs;
105 typedef std::vector<BranchProbability>::iterator probability_iterator;
106 typedef std::vector<BranchProbability>::const_iterator
107 const_probability_iterator;
109 /// Keep track of the physical registers that are livein of the basicblock.
110 typedef std::vector<RegisterMaskPair> LiveInVector;
111 LiveInVector LiveIns;
113 /// Alignment of the basic block. Zero if the basic block does not need to be
114 /// aligned. The alignment is specified as log2(bytes).
115 unsigned Alignment = 0;
117 /// Indicate that this basic block is entered via an exception handler.
118 bool IsEHPad = false;
120 /// Indicate that this basic block is potentially the target of an indirect
122 bool AddressTaken = false;
124 /// Indicate that this basic block is the entry block of an EH funclet.
125 bool IsEHFuncletEntry = false;
127 /// Indicate that this basic block is the entry block of a cleanup funclet.
128 bool IsCleanupFuncletEntry = false;
130 /// \brief since getSymbol is a relatively heavy-weight operation, the symbol
131 /// is only computed once and is cached.
132 mutable MCSymbol *CachedMCSymbol = nullptr;
134 // Intrusive list support
135 MachineBasicBlock() {}
137 explicit MachineBasicBlock(MachineFunction &MF, const BasicBlock *BB);
139 ~MachineBasicBlock();
141 // MachineBasicBlocks are allocated and owned by MachineFunction.
142 friend class MachineFunction;
145 /// Return the LLVM basic block that this instance corresponded to originally.
146 /// Note that this may be NULL if this instance does not correspond directly
147 /// to an LLVM basic block.
148 const BasicBlock *getBasicBlock() const { return BB; }
150 /// Return the name of the corresponding LLVM basic block, or "(null)".
151 StringRef getName() const;
153 /// Return a formatted string to identify this block and its parent function.
154 std::string getFullName() const;
156 /// Test whether this block is potentially the target of an indirect branch.
157 bool hasAddressTaken() const { return AddressTaken; }
159 /// Set this block to reflect that it potentially is the target of an indirect
161 void setHasAddressTaken() { AddressTaken = true; }
163 /// Return the MachineFunction containing this basic block.
164 const MachineFunction *getParent() const { return xParent; }
165 MachineFunction *getParent() { return xParent; }
167 /// MachineBasicBlock iterator that automatically skips over MIs that are
168 /// inside bundles (i.e. walk top level MIs only).
169 template<typename Ty, typename IterTy>
170 class bundle_iterator
171 : public std::iterator<std::bidirectional_iterator_tag, Ty, ptrdiff_t> {
175 bundle_iterator(IterTy MI) : MII(MI) {}
177 bundle_iterator(Ty &MI) : MII(MI) {
178 assert(!MI.isBundledWithPred() &&
179 "It's not legal to initialize bundle_iterator with a bundled MI");
181 bundle_iterator(Ty *MI) : MII(MI) {
182 assert((!MI || !MI->isBundledWithPred()) &&
183 "It's not legal to initialize bundle_iterator with a bundled MI");
185 // Template allows conversion from const to nonconst.
186 template<class OtherTy, class OtherIterTy>
187 bundle_iterator(const bundle_iterator<OtherTy, OtherIterTy> &I)
188 : MII(I.getInstrIterator()) {}
189 bundle_iterator() : MII(nullptr) {}
191 Ty &operator*() const { return *MII; }
192 Ty *operator->() const { return &operator*(); }
194 operator Ty *() const { return MII.getNodePtrUnchecked(); }
196 bool operator==(const bundle_iterator &X) const {
199 bool operator!=(const bundle_iterator &X) const {
200 return !operator==(X);
203 // Increment and decrement operators...
204 bundle_iterator &operator--() { // predecrement - Back up
206 while (MII->isBundledWithPred());
209 bundle_iterator &operator++() { // preincrement - Advance
210 while (MII->isBundledWithSucc())
215 bundle_iterator operator--(int) { // postdecrement operators...
216 bundle_iterator tmp = *this;
220 bundle_iterator operator++(int) { // postincrement operators...
221 bundle_iterator tmp = *this;
226 IterTy getInstrIterator() const {
231 typedef Instructions::iterator instr_iterator;
232 typedef Instructions::const_iterator const_instr_iterator;
233 typedef std::reverse_iterator<instr_iterator> reverse_instr_iterator;
235 std::reverse_iterator<const_instr_iterator> const_reverse_instr_iterator;
238 bundle_iterator<MachineInstr,instr_iterator> iterator;
240 bundle_iterator<const MachineInstr,const_instr_iterator> const_iterator;
241 typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
242 typedef std::reverse_iterator<iterator> reverse_iterator;
245 unsigned size() const { return (unsigned)Insts.size(); }
246 bool empty() const { return Insts.empty(); }
248 MachineInstr &instr_front() { return Insts.front(); }
249 MachineInstr &instr_back() { return Insts.back(); }
250 const MachineInstr &instr_front() const { return Insts.front(); }
251 const MachineInstr &instr_back() const { return Insts.back(); }
253 MachineInstr &front() { return Insts.front(); }
254 MachineInstr &back() { return *--end(); }
255 const MachineInstr &front() const { return Insts.front(); }
256 const MachineInstr &back() const { return *--end(); }
258 instr_iterator instr_begin() { return Insts.begin(); }
259 const_instr_iterator instr_begin() const { return Insts.begin(); }
260 instr_iterator instr_end() { return Insts.end(); }
261 const_instr_iterator instr_end() const { return Insts.end(); }
262 reverse_instr_iterator instr_rbegin() { return Insts.rbegin(); }
263 const_reverse_instr_iterator instr_rbegin() const { return Insts.rbegin(); }
264 reverse_instr_iterator instr_rend () { return Insts.rend(); }
265 const_reverse_instr_iterator instr_rend () const { return Insts.rend(); }
267 iterator begin() { return instr_begin(); }
268 const_iterator begin() const { return instr_begin(); }
269 iterator end () { return instr_end(); }
270 const_iterator end () const { return instr_end(); }
271 reverse_iterator rbegin() { return instr_rbegin(); }
272 const_reverse_iterator rbegin() const { return instr_rbegin(); }
273 reverse_iterator rend () { return instr_rend(); }
274 const_reverse_iterator rend () const { return instr_rend(); }
276 /// Support for MachineInstr::getNextNode().
277 static Instructions MachineBasicBlock::*getSublistAccess(MachineInstr *) {
278 return &MachineBasicBlock::Insts;
281 inline iterator_range<iterator> terminators() {
282 return iterator_range<iterator>(getFirstTerminator(), end());
284 inline iterator_range<const_iterator> terminators() const {
285 return iterator_range<const_iterator>(getFirstTerminator(), end());
288 // Machine-CFG iterators
289 typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
290 typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
291 typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
292 typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
293 typedef std::vector<MachineBasicBlock *>::reverse_iterator
294 pred_reverse_iterator;
295 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
296 const_pred_reverse_iterator;
297 typedef std::vector<MachineBasicBlock *>::reverse_iterator
298 succ_reverse_iterator;
299 typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
300 const_succ_reverse_iterator;
301 pred_iterator pred_begin() { return Predecessors.begin(); }
302 const_pred_iterator pred_begin() const { return Predecessors.begin(); }
303 pred_iterator pred_end() { return Predecessors.end(); }
304 const_pred_iterator pred_end() const { return Predecessors.end(); }
305 pred_reverse_iterator pred_rbegin()
306 { return Predecessors.rbegin();}
307 const_pred_reverse_iterator pred_rbegin() const
308 { return Predecessors.rbegin();}
309 pred_reverse_iterator pred_rend()
310 { return Predecessors.rend(); }
311 const_pred_reverse_iterator pred_rend() const
312 { return Predecessors.rend(); }
313 unsigned pred_size() const {
314 return (unsigned)Predecessors.size();
316 bool pred_empty() const { return Predecessors.empty(); }
317 succ_iterator succ_begin() { return Successors.begin(); }
318 const_succ_iterator succ_begin() const { return Successors.begin(); }
319 succ_iterator succ_end() { return Successors.end(); }
320 const_succ_iterator succ_end() const { return Successors.end(); }
321 succ_reverse_iterator succ_rbegin()
322 { return Successors.rbegin(); }
323 const_succ_reverse_iterator succ_rbegin() const
324 { return Successors.rbegin(); }
325 succ_reverse_iterator succ_rend()
326 { return Successors.rend(); }
327 const_succ_reverse_iterator succ_rend() const
328 { return Successors.rend(); }
329 unsigned succ_size() const {
330 return (unsigned)Successors.size();
332 bool succ_empty() const { return Successors.empty(); }
334 inline iterator_range<pred_iterator> predecessors() {
335 return iterator_range<pred_iterator>(pred_begin(), pred_end());
337 inline iterator_range<const_pred_iterator> predecessors() const {
338 return iterator_range<const_pred_iterator>(pred_begin(), pred_end());
340 inline iterator_range<succ_iterator> successors() {
341 return iterator_range<succ_iterator>(succ_begin(), succ_end());
343 inline iterator_range<const_succ_iterator> successors() const {
344 return iterator_range<const_succ_iterator>(succ_begin(), succ_end());
347 // LiveIn management methods.
349 /// Adds the specified register as a live in. Note that it is an error to add
350 /// the same register to the same set more than once unless the intention is
351 /// to call sortUniqueLiveIns after all registers are added.
352 void addLiveIn(MCPhysReg PhysReg, LaneBitmask LaneMask = ~0u) {
353 LiveIns.push_back(RegisterMaskPair(PhysReg, LaneMask));
355 void addLiveIn(const RegisterMaskPair &RegMaskPair) {
356 LiveIns.push_back(RegMaskPair);
359 /// Sorts and uniques the LiveIns vector. It can be significantly faster to do
360 /// this than repeatedly calling isLiveIn before calling addLiveIn for every
361 /// LiveIn insertion.
362 void sortUniqueLiveIns();
364 /// Add PhysReg as live in to this block, and ensure that there is a copy of
365 /// PhysReg to a virtual register of class RC. Return the virtual register
366 /// that is a copy of the live in PhysReg.
367 unsigned addLiveIn(MCPhysReg PhysReg, const TargetRegisterClass *RC);
369 /// Remove the specified register from the live in set.
370 void removeLiveIn(MCPhysReg Reg, LaneBitmask LaneMask = ~0u);
372 /// Return true if the specified register is in the live in set.
373 bool isLiveIn(MCPhysReg Reg, LaneBitmask LaneMask = ~0u) const;
375 // Iteration support for live in sets. These sets are kept in sorted
376 // order by their register number.
377 typedef LiveInVector::const_iterator livein_iterator;
378 livein_iterator livein_begin() const { return LiveIns.begin(); }
379 livein_iterator livein_end() const { return LiveIns.end(); }
380 bool livein_empty() const { return LiveIns.empty(); }
381 iterator_range<livein_iterator> liveins() const {
382 return make_range(livein_begin(), livein_end());
385 /// Get the clobber mask for the start of this basic block. Funclets use this
386 /// to prevent register allocation across funclet transitions.
387 const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const;
389 /// Get the clobber mask for the end of the basic block.
390 /// \see getBeginClobberMask()
391 const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const;
393 /// Return alignment of the basic block. The alignment is specified as
395 unsigned getAlignment() const { return Alignment; }
397 /// Set alignment of the basic block. The alignment is specified as
399 void setAlignment(unsigned Align) { Alignment = Align; }
401 /// Returns true if the block is a landing pad. That is this basic block is
402 /// entered via an exception handler.
403 bool isEHPad() const { return IsEHPad; }
405 /// Indicates the block is a landing pad. That is this basic block is entered
406 /// via an exception handler.
407 void setIsEHPad(bool V = true) { IsEHPad = V; }
409 /// If this block has a successor that is a landing pad, return it. Otherwise
411 const MachineBasicBlock *getLandingPadSuccessor() const;
413 bool hasEHPadSuccessor() const;
415 /// Returns true if this is the entry block of an EH funclet.
416 bool isEHFuncletEntry() const { return IsEHFuncletEntry; }
418 /// Indicates if this is the entry block of an EH funclet.
419 void setIsEHFuncletEntry(bool V = true) { IsEHFuncletEntry = V; }
421 /// Returns true if this is the entry block of a cleanup funclet.
422 bool isCleanupFuncletEntry() const { return IsCleanupFuncletEntry; }
424 /// Indicates if this is the entry block of a cleanup funclet.
425 void setIsCleanupFuncletEntry(bool V = true) { IsCleanupFuncletEntry = V; }
427 // Code Layout methods.
429 /// Move 'this' block before or after the specified block. This only moves
430 /// the block, it does not modify the CFG or adjust potential fall-throughs at
431 /// the end of the block.
432 void moveBefore(MachineBasicBlock *NewAfter);
433 void moveAfter(MachineBasicBlock *NewBefore);
435 /// Update the terminator instructions in block to account for changes to the
436 /// layout. If the block previously used a fallthrough, it may now need a
437 /// branch, and if it previously used branching it may now be able to use a
439 void updateTerminator();
441 // Machine-CFG mutators
443 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
444 /// of Succ is automatically updated. WEIGHT parameter is stored in Weights
445 /// list and it may be used by MachineBranchProbabilityInfo analysis to
446 /// calculate branch probability.
448 /// Note that duplicate Machine CFG edges are not allowed.
449 void addSuccessor(MachineBasicBlock *Succ, uint32_t Weight = 0);
451 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
452 /// of Succ is automatically updated. The weight is not provided because BPI
453 /// is not available (e.g. -O0 is used), in which case edge weights won't be
454 /// used. Using this interface can save some space.
455 void addSuccessorWithoutWeight(MachineBasicBlock *Succ);
457 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
458 /// of Succ is automatically updated. PROB parameter is stored in
459 /// Probabilities list.
461 /// Note that duplicate Machine CFG edges are not allowed.
462 void addSuccessor(MachineBasicBlock *Succ, BranchProbability Prob);
464 /// Add Succ as a successor of this MachineBasicBlock. The Predecessors list
465 /// of Succ is automatically updated. The probability is not provided because
466 /// BPI is not available (e.g. -O0 is used), in which case edge probabilities
467 /// won't be used. Using this interface can save some space.
468 void addSuccessorWithoutProb(MachineBasicBlock *Succ);
470 /// Set successor weight of a given iterator.
471 void setSuccWeight(succ_iterator I, uint32_t Weight);
473 /// Set successor probability of a given iterator.
474 void setSuccProbability(succ_iterator I, BranchProbability Prob);
476 /// Normalize probabilities of all successors so that the sum of them becomes
478 void normalizeSuccProbs() {
479 BranchProbability::normalizeProbabilities(Probs.begin(), Probs.end());
482 /// Remove successor from the successors list of this MachineBasicBlock. The
483 /// Predecessors list of Succ is automatically updated.
484 void removeSuccessor(MachineBasicBlock *Succ);
486 /// Remove specified successor from the successors list of this
487 /// MachineBasicBlock. The Predecessors list of Succ is automatically updated.
488 /// Return the iterator to the element after the one removed.
489 succ_iterator removeSuccessor(succ_iterator I);
491 /// Replace successor OLD with NEW and update weight info.
492 void replaceSuccessor(MachineBasicBlock *Old, MachineBasicBlock *New);
494 /// Transfers all the successors from MBB to this machine basic block (i.e.,
495 /// copies all the successors FromMBB and remove all the successors from
497 void transferSuccessors(MachineBasicBlock *FromMBB);
499 /// Transfers all the successors, as in transferSuccessors, and update PHI
500 /// operands in the successor blocks which refer to FromMBB to refer to this.
501 void transferSuccessorsAndUpdatePHIs(MachineBasicBlock *FromMBB);
503 /// Return true if any of the successors have weights attached to them.
504 bool hasSuccessorWeights() const { return !Weights.empty(); }
506 /// Return true if any of the successors have probabilities attached to them.
507 bool hasSuccessorProbabilities() const { return !Probs.empty(); }
509 /// Return true if the specified MBB is a predecessor of this block.
510 bool isPredecessor(const MachineBasicBlock *MBB) const;
512 /// Return true if the specified MBB is a successor of this block.
513 bool isSuccessor(const MachineBasicBlock *MBB) const;
515 /// Return true if the specified MBB will be emitted immediately after this
516 /// block, such that if this block exits by falling through, control will
517 /// transfer to the specified MBB. Note that MBB need not be a successor at
518 /// all, for example if this block ends with an unconditional branch to some
520 bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
522 /// Return true if the block can implicitly transfer control to the block
523 /// after it by falling off the end of it. This should return false if it can
524 /// reach the block after it, but it uses an explicit branch to do so (e.g., a
525 /// table jump). True is a conservative answer.
526 bool canFallThrough();
528 /// Returns a pointer to the first instruction in this block that is not a
529 /// PHINode instruction. When adding instructions to the beginning of the
530 /// basic block, they should be added before the returned value, not before
531 /// the first instruction, which might be PHI.
532 /// Returns end() is there's no non-PHI instruction.
533 iterator getFirstNonPHI();
535 /// Return the first instruction in MBB after I that is not a PHI or a label.
536 /// This is the correct point to insert copies at the beginning of a basic
538 iterator SkipPHIsAndLabels(iterator I);
540 /// Returns an iterator to the first terminator instruction of this basic
541 /// block. If a terminator does not exist, it returns end().
542 iterator getFirstTerminator();
543 const_iterator getFirstTerminator() const {
544 return const_cast<MachineBasicBlock *>(this)->getFirstTerminator();
547 /// Same getFirstTerminator but it ignores bundles and return an
548 /// instr_iterator instead.
549 instr_iterator getFirstInstrTerminator();
551 /// Returns an iterator to the first non-debug instruction in the basic block,
553 iterator getFirstNonDebugInstr();
554 const_iterator getFirstNonDebugInstr() const {
555 return const_cast<MachineBasicBlock *>(this)->getFirstNonDebugInstr();
558 /// Returns an iterator to the last non-debug instruction in the basic block,
560 iterator getLastNonDebugInstr();
561 const_iterator getLastNonDebugInstr() const {
562 return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
565 /// Convenience function that returns true if the block ends in a return
567 bool isReturnBlock() const {
568 return !empty() && back().isReturn();
571 /// Split the critical edge from this block to the given successor block, and
572 /// return the newly created block, or null if splitting is not possible.
574 /// This function updates LiveVariables, MachineDominatorTree, and
575 /// MachineLoopInfo, as applicable.
576 MachineBasicBlock *SplitCriticalEdge(MachineBasicBlock *Succ, Pass *P);
578 void pop_front() { Insts.pop_front(); }
579 void pop_back() { Insts.pop_back(); }
580 void push_back(MachineInstr *MI) { Insts.push_back(MI); }
582 /// Insert MI into the instruction list before I, possibly inside a bundle.
584 /// If the insertion point is inside a bundle, MI will be added to the bundle,
585 /// otherwise MI will not be added to any bundle. That means this function
586 /// alone can't be used to prepend or append instructions to bundles. See
587 /// MIBundleBuilder::insert() for a more reliable way of doing that.
588 instr_iterator insert(instr_iterator I, MachineInstr *M);
590 /// Insert a range of instructions into the instruction list before I.
591 template<typename IT>
592 void insert(iterator I, IT S, IT E) {
593 assert((I == end() || I->getParent() == this) &&
594 "iterator points outside of basic block");
595 Insts.insert(I.getInstrIterator(), S, E);
598 /// Insert MI into the instruction list before I.
599 iterator insert(iterator I, MachineInstr *MI) {
600 assert((I == end() || I->getParent() == this) &&
601 "iterator points outside of basic block");
602 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
603 "Cannot insert instruction with bundle flags");
604 return Insts.insert(I.getInstrIterator(), MI);
607 /// Insert MI into the instruction list after I.
608 iterator insertAfter(iterator I, MachineInstr *MI) {
609 assert((I == end() || I->getParent() == this) &&
610 "iterator points outside of basic block");
611 assert(!MI->isBundledWithPred() && !MI->isBundledWithSucc() &&
612 "Cannot insert instruction with bundle flags");
613 return Insts.insertAfter(I.getInstrIterator(), MI);
616 /// Remove an instruction from the instruction list and delete it.
618 /// If the instruction is part of a bundle, the other instructions in the
619 /// bundle will still be bundled after removing the single instruction.
620 instr_iterator erase(instr_iterator I);
622 /// Remove an instruction from the instruction list and delete it.
624 /// If the instruction is part of a bundle, the other instructions in the
625 /// bundle will still be bundled after removing the single instruction.
626 instr_iterator erase_instr(MachineInstr *I) {
627 return erase(instr_iterator(I));
630 /// Remove a range of instructions from the instruction list and delete them.
631 iterator erase(iterator I, iterator E) {
632 return Insts.erase(I.getInstrIterator(), E.getInstrIterator());
635 /// Remove an instruction or bundle from the instruction list and delete it.
637 /// If I points to a bundle of instructions, they are all erased.
638 iterator erase(iterator I) {
639 return erase(I, std::next(I));
642 /// Remove an instruction from the instruction list and delete it.
644 /// If I is the head of a bundle of instructions, the whole bundle will be
646 iterator erase(MachineInstr *I) {
647 return erase(iterator(I));
650 /// Remove the unbundled instruction from the instruction list without
653 /// This function can not be used to remove bundled instructions, use
654 /// remove_instr to remove individual instructions from a bundle.
655 MachineInstr *remove(MachineInstr *I) {
656 assert(!I->isBundled() && "Cannot remove bundled instructions");
657 return Insts.remove(instr_iterator(I));
660 /// Remove the possibly bundled instruction from the instruction list
661 /// without deleting it.
663 /// If the instruction is part of a bundle, the other instructions in the
664 /// bundle will still be bundled after removing the single instruction.
665 MachineInstr *remove_instr(MachineInstr *I);
671 /// Take an instruction from MBB 'Other' at the position From, and insert it
672 /// into this MBB right before 'Where'.
674 /// If From points to a bundle of instructions, the whole bundle is moved.
675 void splice(iterator Where, MachineBasicBlock *Other, iterator From) {
676 // The range splice() doesn't allow noop moves, but this one does.
678 splice(Where, Other, From, std::next(From));
681 /// Take a block of instructions from MBB 'Other' in the range [From, To),
682 /// and insert them into this MBB right before 'Where'.
684 /// The instruction at 'Where' must not be included in the range of
685 /// instructions to move.
686 void splice(iterator Where, MachineBasicBlock *Other,
687 iterator From, iterator To) {
688 Insts.splice(Where.getInstrIterator(), Other->Insts,
689 From.getInstrIterator(), To.getInstrIterator());
692 /// This method unlinks 'this' from the containing function, and returns it,
693 /// but does not delete it.
694 MachineBasicBlock *removeFromParent();
696 /// This method unlinks 'this' from the containing function and deletes it.
697 void eraseFromParent();
699 /// Given a machine basic block that branched to 'Old', change the code and
700 /// CFG so that it branches to 'New' instead.
701 void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
703 /// Various pieces of code can cause excess edges in the CFG to be inserted.
704 /// If we have proven that MBB can only branch to DestA and DestB, remove any
705 /// other MBB successors from the CFG. DestA and DestB can be null. Besides
706 /// DestA and DestB, retain other edges leading to LandingPads (currently
707 /// there can be only one; we don't check or require that here). Note it is
708 /// possible that DestA and/or DestB are LandingPads.
709 bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
710 MachineBasicBlock *DestB,
713 /// Find the next valid DebugLoc starting at MBBI, skipping any DBG_VALUE
714 /// instructions. Return UnknownLoc if there is none.
715 DebugLoc findDebugLoc(instr_iterator MBBI);
716 DebugLoc findDebugLoc(iterator MBBI) {
717 return findDebugLoc(MBBI.getInstrIterator());
720 /// Possible outcome of a register liveness query to computeRegisterLiveness()
721 enum LivenessQueryResult {
722 LQR_Live, ///< Register is known to be live.
723 LQR_OverlappingLive, ///< Register itself is not live, but some overlapping
725 LQR_Dead, ///< Register is known to be dead.
726 LQR_Unknown ///< Register liveness not decidable from local
730 /// Return whether (physical) register \p Reg has been <def>ined and not
731 /// <kill>ed as of just before \p Before.
733 /// Search is localised to a neighborhood of \p Neighborhood instructions
734 /// before (searching for defs or kills) and \p Neighborhood instructions
735 /// after (searching just for defs) \p Before.
737 /// \p Reg must be a physical register.
738 LivenessQueryResult computeRegisterLiveness(const TargetRegisterInfo *TRI,
740 const_iterator Before,
741 unsigned Neighborhood=10) const;
743 // Debugging methods.
745 void print(raw_ostream &OS, SlotIndexes* = nullptr) const;
746 void print(raw_ostream &OS, ModuleSlotTracker &MST,
747 SlotIndexes * = nullptr) const;
749 // Printing method used by LoopInfo.
750 void printAsOperand(raw_ostream &OS, bool PrintType = true) const;
752 /// MachineBasicBlocks are uniquely numbered at the function level, unless
753 /// they're not in a MachineFunction yet, in which case this will return -1.
754 int getNumber() const { return Number; }
755 void setNumber(int N) { Number = N; }
757 /// Return the MCSymbol for this basic block.
758 MCSymbol *getSymbol() const;
762 /// Return weight iterator corresponding to the I successor iterator.
763 weight_iterator getWeightIterator(succ_iterator I);
764 const_weight_iterator getWeightIterator(const_succ_iterator I) const;
766 /// Return probability iterator corresponding to the I successor iterator.
767 probability_iterator getProbabilityIterator(succ_iterator I);
768 const_probability_iterator
769 getProbabilityIterator(const_succ_iterator I) const;
771 friend class MachineBranchProbabilityInfo;
772 friend class MIPrinter;
774 /// Return weight of the edge from this block to MBB. This method should NOT
775 /// be called directly, but by using getEdgeWeight method from
776 /// MachineBranchProbabilityInfo class.
777 uint32_t getSuccWeight(const_succ_iterator Succ) const;
779 /// Return probability of the edge from this block to MBB. This method should
780 /// NOT be called directly, but by using getEdgeProbability method from
781 /// MachineBranchProbabilityInfo class.
782 BranchProbability getSuccProbability(const_succ_iterator Succ) const;
784 // Methods used to maintain doubly linked list of blocks...
785 friend struct ilist_traits<MachineBasicBlock>;
787 // Machine-CFG mutators
789 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this
790 /// unless you know what you're doing, because it doesn't update Pred's
791 /// successors list. Use Pred->addSuccessor instead.
792 void addPredecessor(MachineBasicBlock *Pred);
794 /// Remove Pred as a predecessor of this MachineBasicBlock. Don't do this
795 /// unless you know what you're doing, because it doesn't update Pred's
796 /// successors list. Use Pred->removeSuccessor instead.
797 void removePredecessor(MachineBasicBlock *Pred);
800 raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
802 // This is useful when building IndexedMaps keyed on basic block pointers.
803 struct MBB2NumberFunctor :
804 public std::unary_function<const MachineBasicBlock*, unsigned> {
805 unsigned operator()(const MachineBasicBlock *MBB) const {
806 return MBB->getNumber();
810 //===--------------------------------------------------------------------===//
811 // GraphTraits specializations for machine basic block graphs (machine-CFGs)
812 //===--------------------------------------------------------------------===//
814 // Provide specializations of GraphTraits to be able to treat a
815 // MachineFunction as a graph of MachineBasicBlocks.
818 template <> struct GraphTraits<MachineBasicBlock *> {
819 typedef MachineBasicBlock NodeType;
820 typedef MachineBasicBlock::succ_iterator ChildIteratorType;
822 static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
823 static inline ChildIteratorType child_begin(NodeType *N) {
824 return N->succ_begin();
826 static inline ChildIteratorType child_end(NodeType *N) {
827 return N->succ_end();
831 template <> struct GraphTraits<const MachineBasicBlock *> {
832 typedef const MachineBasicBlock NodeType;
833 typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
835 static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
836 static inline ChildIteratorType child_begin(NodeType *N) {
837 return N->succ_begin();
839 static inline ChildIteratorType child_end(NodeType *N) {
840 return N->succ_end();
844 // Provide specializations of GraphTraits to be able to treat a
845 // MachineFunction as a graph of MachineBasicBlocks and to walk it
846 // in inverse order. Inverse order for a function is considered
847 // to be when traversing the predecessor edges of a MBB
848 // instead of the successor edges.
850 template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
851 typedef MachineBasicBlock NodeType;
852 typedef MachineBasicBlock::pred_iterator ChildIteratorType;
853 static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
856 static inline ChildIteratorType child_begin(NodeType *N) {
857 return N->pred_begin();
859 static inline ChildIteratorType child_end(NodeType *N) {
860 return N->pred_end();
864 template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
865 typedef const MachineBasicBlock NodeType;
866 typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
867 static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
870 static inline ChildIteratorType child_begin(NodeType *N) {
871 return N->pred_begin();
873 static inline ChildIteratorType child_end(NodeType *N) {
874 return N->pred_end();
880 /// MachineInstrSpan provides an interface to get an iteration range
881 /// containing the instruction it was initialized with, along with all
882 /// those instructions inserted prior to or following that instruction
883 /// at some point after the MachineInstrSpan is constructed.
884 class MachineInstrSpan {
885 MachineBasicBlock &MBB;
886 MachineBasicBlock::iterator I, B, E;
888 MachineInstrSpan(MachineBasicBlock::iterator I)
889 : MBB(*I->getParent()),
891 B(I == MBB.begin() ? MBB.end() : std::prev(I)),
894 MachineBasicBlock::iterator begin() {
895 return B == MBB.end() ? MBB.begin() : std::next(B);
897 MachineBasicBlock::iterator end() { return E; }
898 bool empty() { return begin() == end(); }
900 MachineBasicBlock::iterator getInitial() { return I; }
903 } // End llvm namespace