1 //===- llvm/CodeGen/SlotIndexes.h - Slot indexes representation -*- 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 // This file implements SlotIndex and related classes. The purpose of SlotIndex
11 // is to describe a position at which a register can become live, or cease to
14 // SlotIndex is mostly a proxy for entries of the SlotIndexList, a class which
15 // is held is LiveIntervals and provides the real numbering. This allows
16 // LiveIntervals to perform largely transparent renumbering.
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_CODEGEN_SLOTINDEXES_H
20 #define LLVM_CODEGEN_SLOTINDEXES_H
22 #include "llvm/CodeGen/MachineBasicBlock.h"
23 #include "llvm/CodeGen/MachineFunction.h"
24 #include "llvm/CodeGen/MachineFunctionPass.h"
25 #include "llvm/ADT/PointerIntPair.h"
26 #include "llvm/ADT/SmallVector.h"
27 #include "llvm/ADT/DenseMap.h"
28 #include "llvm/Support/Allocator.h"
32 /// This class represents an entry in the slot index list held in the
33 /// SlotIndexes pass. It should not be used directly. See the
34 /// SlotIndex & SlotIndexes classes for the public interface to this
36 class IndexListEntry {
37 IndexListEntry *next, *prev;
43 IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi), index(index) {}
45 MachineInstr* getInstr() const { return mi; }
46 void setInstr(MachineInstr *mi) {
50 unsigned getIndex() const { return index; }
51 void setIndex(unsigned index) {
55 IndexListEntry* getNext() { return next; }
56 const IndexListEntry* getNext() const { return next; }
57 void setNext(IndexListEntry *next) {
61 IndexListEntry* getPrev() { return prev; }
62 const IndexListEntry* getPrev() const { return prev; }
63 void setPrev(IndexListEntry *prev) {
68 // Specialize PointerLikeTypeTraits for IndexListEntry.
70 class PointerLikeTypeTraits<IndexListEntry*> {
72 static inline void* getAsVoidPointer(IndexListEntry *p) {
75 static inline IndexListEntry* getFromVoidPointer(void *p) {
76 return static_cast<IndexListEntry*>(p);
78 enum { NumLowBitsAvailable = 3 };
81 /// SlotIndex - An opaque wrapper around machine indexes.
83 friend class SlotIndexes;
84 friend struct DenseMapInfo<SlotIndex>;
87 /// Basic block boundary. Used for live ranges entering and leaving a
88 /// block without being live in the layout neighbor. Also used as the
89 /// def slot of PHI-defs.
92 /// Early-clobber register use/def slot. A live range defined at
93 /// Slot_EarlyCLobber interferes with normal live ranges killed at
94 /// Slot_Register. Also used as the kill slot for live ranges tied to an
95 /// early-clobber def.
98 /// Normal register use/def slot. Normal instructions kill and define
99 /// register live ranges at this slot.
102 /// Dead def kill point. Kill slot for a live range that is defined by
103 /// the same instruction (Slot_Register or Slot_EarlyClobber), but isn't
110 PointerIntPair<IndexListEntry*, 2, unsigned> lie;
112 SlotIndex(IndexListEntry *entry, unsigned slot)
113 : lie(entry, slot) {}
115 IndexListEntry& entry() const {
116 assert(isValid() && "Attempt to compare reserved index.");
117 return *lie.getPointer();
120 int getIndex() const {
121 return entry().getIndex() | getSlot();
124 /// Returns the slot for this SlotIndex.
125 Slot getSlot() const {
126 return static_cast<Slot>(lie.getInt());
129 static inline unsigned getHashValue(const SlotIndex &v) {
130 void *ptrVal = v.lie.getOpaqueValue();
131 return (unsigned((intptr_t)ptrVal)) ^ (unsigned((intptr_t)ptrVal) >> 9);
136 /// The default distance between instructions as returned by distance().
137 /// This may vary as instructions are inserted and removed.
138 InstrDist = 4 * Slot_Count
141 static inline SlotIndex getEmptyKey() {
142 return SlotIndex(0, 1);
145 static inline SlotIndex getTombstoneKey() {
146 return SlotIndex(0, 2);
149 /// Construct an invalid index.
150 SlotIndex() : lie(0, 0) {}
152 // Construct a new slot index from the given one, and set the slot.
153 SlotIndex(const SlotIndex &li, Slot s)
154 : lie(&li.entry(), unsigned(s)) {
155 assert(lie.getPointer() != 0 &&
156 "Attempt to construct index with 0 pointer.");
159 /// Returns true if this is a valid index. Invalid indicies do
160 /// not point into an index table, and cannot be compared.
161 bool isValid() const {
162 return lie.getPointer();
165 /// Return true for a valid index.
166 operator bool() const { return isValid(); }
168 /// Print this index to the given raw_ostream.
169 void print(raw_ostream &os) const;
171 /// Dump this index to stderr.
174 /// Compare two SlotIndex objects for equality.
175 bool operator==(SlotIndex other) const {
176 return lie == other.lie;
178 /// Compare two SlotIndex objects for inequality.
179 bool operator!=(SlotIndex other) const {
180 return lie != other.lie;
183 /// Compare two SlotIndex objects. Return true if the first index
184 /// is strictly lower than the second.
185 bool operator<(SlotIndex other) const {
186 return getIndex() < other.getIndex();
188 /// Compare two SlotIndex objects. Return true if the first index
189 /// is lower than, or equal to, the second.
190 bool operator<=(SlotIndex other) const {
191 return getIndex() <= other.getIndex();
194 /// Compare two SlotIndex objects. Return true if the first index
195 /// is greater than the second.
196 bool operator>(SlotIndex other) const {
197 return getIndex() > other.getIndex();
200 /// Compare two SlotIndex objects. Return true if the first index
201 /// is greater than, or equal to, the second.
202 bool operator>=(SlotIndex other) const {
203 return getIndex() >= other.getIndex();
206 /// isSameInstr - Return true if A and B refer to the same instruction.
207 static bool isSameInstr(SlotIndex A, SlotIndex B) {
208 return A.lie.getPointer() == B.lie.getPointer();
211 /// isEarlierInstr - Return true if A refers to an instruction earlier than
212 /// B. This is equivalent to A < B && !isSameInstr(A, B).
213 static bool isEarlierInstr(SlotIndex A, SlotIndex B) {
214 return A.entry().getIndex() < B.entry().getIndex();
217 /// Return the distance from this index to the given one.
218 int distance(SlotIndex other) const {
219 return other.getIndex() - getIndex();
222 /// isBlock - Returns true if this is a block boundary slot.
223 bool isBlock() const { return getSlot() == Slot_Block; }
225 /// isEarlyClobber - Returns true if this is an early-clobber slot.
226 bool isEarlyClobber() const { return getSlot() == Slot_EarlyClobber; }
228 /// isRegister - Returns true if this is a normal register use/def slot.
229 /// Note that early-clobber slots may also be used for uses and defs.
230 bool isRegister() const { return getSlot() == Slot_Register; }
232 /// isDead - Returns true if this is a dead def kill slot.
233 bool isDead() const { return getSlot() == Slot_Dead; }
235 /// Returns the base index for associated with this index. The base index
236 /// is the one associated with the Slot_Block slot for the instruction
237 /// pointed to by this index.
238 SlotIndex getBaseIndex() const {
239 return SlotIndex(&entry(), Slot_Block);
242 /// Returns the boundary index for associated with this index. The boundary
243 /// index is the one associated with the Slot_Block slot for the instruction
244 /// pointed to by this index.
245 SlotIndex getBoundaryIndex() const {
246 return SlotIndex(&entry(), Slot_Dead);
249 /// Returns the register use/def slot in the current instruction for a
250 /// normal or early-clobber def.
251 SlotIndex getRegSlot(bool EC = false) const {
252 return SlotIndex(&entry(), EC ? Slot_EarlyClobber : Slot_Register);
255 /// Returns the dead def kill slot for the current instruction.
256 SlotIndex getDeadSlot() const {
257 return SlotIndex(&entry(), Slot_Dead);
260 /// Returns the next slot in the index list. This could be either the
261 /// next slot for the instruction pointed to by this index or, if this
262 /// index is a STORE, the first slot for the next instruction.
263 /// WARNING: This method is considerably more expensive than the methods
264 /// that return specific slots (getUseIndex(), etc). If you can - please
265 /// use one of those methods.
266 SlotIndex getNextSlot() const {
268 if (s == Slot_Dead) {
269 return SlotIndex(entry().getNext(), Slot_Block);
271 return SlotIndex(&entry(), s + 1);
274 /// Returns the next index. This is the index corresponding to the this
275 /// index's slot, but for the next instruction.
276 SlotIndex getNextIndex() const {
277 return SlotIndex(entry().getNext(), getSlot());
280 /// Returns the previous slot in the index list. This could be either the
281 /// previous slot for the instruction pointed to by this index or, if this
282 /// index is a Slot_Block, the last slot for the previous instruction.
283 /// WARNING: This method is considerably more expensive than the methods
284 /// that return specific slots (getUseIndex(), etc). If you can - please
285 /// use one of those methods.
286 SlotIndex getPrevSlot() const {
288 if (s == Slot_Block) {
289 return SlotIndex(entry().getPrev(), Slot_Dead);
291 return SlotIndex(&entry(), s - 1);
294 /// Returns the previous index. This is the index corresponding to this
295 /// index's slot, but for the previous instruction.
296 SlotIndex getPrevIndex() const {
297 return SlotIndex(entry().getPrev(), getSlot());
302 /// DenseMapInfo specialization for SlotIndex.
304 struct DenseMapInfo<SlotIndex> {
305 static inline SlotIndex getEmptyKey() {
306 return SlotIndex::getEmptyKey();
308 static inline SlotIndex getTombstoneKey() {
309 return SlotIndex::getTombstoneKey();
311 static inline unsigned getHashValue(const SlotIndex &v) {
312 return SlotIndex::getHashValue(v);
314 static inline bool isEqual(const SlotIndex &LHS, const SlotIndex &RHS) {
319 template <> struct isPodLike<SlotIndex> { static const bool value = true; };
322 inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
327 typedef std::pair<SlotIndex, MachineBasicBlock*> IdxMBBPair;
329 inline bool operator<(SlotIndex V, const IdxMBBPair &IM) {
333 inline bool operator<(const IdxMBBPair &IM, SlotIndex V) {
337 struct Idx2MBBCompare {
338 bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
339 return LHS.first < RHS.first;
343 /// SlotIndexes pass.
345 /// This pass assigns indexes to each instruction.
346 class SlotIndexes : public MachineFunctionPass {
350 IndexListEntry *indexListHead;
351 unsigned functionSize;
353 typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap;
356 /// MBBRanges - Map MBB number to (start, stop) indexes.
357 SmallVector<std::pair<SlotIndex, SlotIndex>, 8> MBBRanges;
359 /// Idx2MBBMap - Sorted list of pairs of index of first instruction
361 SmallVector<IdxMBBPair, 8> idx2MBBMap;
363 // IndexListEntry allocator.
364 BumpPtrAllocator ileAllocator;
366 IndexListEntry* createEntry(MachineInstr *mi, unsigned index) {
367 IndexListEntry *entry =
368 static_cast<IndexListEntry*>(
369 ileAllocator.Allocate(sizeof(IndexListEntry),
370 alignOf<IndexListEntry>()));
372 new (entry) IndexListEntry(mi, index);
378 assert(indexListHead == 0 && "Zero entry non-null at initialisation.");
379 indexListHead = createEntry(0, ~0U);
380 indexListHead->setNext(0);
381 indexListHead->setPrev(indexListHead);
386 ileAllocator.Reset();
389 IndexListEntry* getTail() {
390 assert(indexListHead != 0 && "Call to getTail on uninitialized list.");
391 return indexListHead->getPrev();
394 const IndexListEntry* getTail() const {
395 assert(indexListHead != 0 && "Call to getTail on uninitialized list.");
396 return indexListHead->getPrev();
399 // Returns true if the index list is empty.
400 bool empty() const { return (indexListHead == getTail()); }
402 IndexListEntry* front() {
403 assert(!empty() && "front() called on empty index list.");
404 return indexListHead;
407 const IndexListEntry* front() const {
408 assert(!empty() && "front() called on empty index list.");
409 return indexListHead;
412 IndexListEntry* back() {
413 assert(!empty() && "back() called on empty index list.");
414 return getTail()->getPrev();
417 const IndexListEntry* back() const {
418 assert(!empty() && "back() called on empty index list.");
419 return getTail()->getPrev();
422 /// Insert a new entry before itr.
423 void insert(IndexListEntry *itr, IndexListEntry *val) {
424 assert(itr != 0 && "itr should not be null.");
425 IndexListEntry *prev = itr->getPrev();
429 if (itr != indexListHead) {
438 /// Push a new entry on to the end of the list.
439 void push_back(IndexListEntry *val) {
440 insert(getTail(), val);
443 /// Renumber locally after inserting newEntry.
444 void renumberIndexes(IndexListEntry *newEntry);
449 SlotIndexes() : MachineFunctionPass(ID), indexListHead(0) {
450 initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
453 virtual void getAnalysisUsage(AnalysisUsage &au) const;
454 virtual void releaseMemory();
456 virtual bool runOnMachineFunction(MachineFunction &fn);
458 /// Dump the indexes.
461 /// Renumber the index list, providing space for new instructions.
462 void renumberIndexes();
464 /// Returns the zero index for this analysis.
465 SlotIndex getZeroIndex() {
466 assert(front()->getIndex() == 0 && "First index is not 0?");
467 return SlotIndex(front(), 0);
470 /// Returns the base index of the last slot in this analysis.
471 SlotIndex getLastIndex() {
472 return SlotIndex(back(), 0);
475 /// Returns the distance between the highest and lowest indexes allocated
477 unsigned getIndexesLength() const {
478 assert(front()->getIndex() == 0 &&
479 "Initial index isn't zero?");
481 return back()->getIndex();
484 /// Returns the number of instructions in the function.
485 unsigned getFunctionSize() const {
489 /// Returns true if the given machine instr is mapped to an index,
490 /// otherwise returns false.
491 bool hasIndex(const MachineInstr *instr) const {
492 return mi2iMap.count(instr);
495 /// Returns the base index for the given instruction.
496 SlotIndex getInstructionIndex(const MachineInstr *instr) const {
497 Mi2IndexMap::const_iterator itr = mi2iMap.find(instr);
498 assert(itr != mi2iMap.end() && "Instruction not found in maps.");
502 /// Returns the instruction for the given index, or null if the given
503 /// index has no instruction associated with it.
504 MachineInstr* getInstructionFromIndex(SlotIndex index) const {
505 return index.isValid() ? index.entry().getInstr() : 0;
508 /// Returns the next non-null index.
509 SlotIndex getNextNonNullIndex(SlotIndex index) {
510 SlotIndex nextNonNull = index.getNextIndex();
512 while (&nextNonNull.entry() != getTail() &&
513 getInstructionFromIndex(nextNonNull) == 0) {
514 nextNonNull = nextNonNull.getNextIndex();
520 /// getIndexBefore - Returns the index of the last indexed instruction
521 /// before MI, or the the start index of its basic block.
522 /// MI is not required to have an index.
523 SlotIndex getIndexBefore(const MachineInstr *MI) const {
524 const MachineBasicBlock *MBB = MI->getParent();
525 assert(MBB && "MI must be inserted inna basic block");
526 MachineBasicBlock::const_iterator I = MI, B = MBB->begin();
529 return getMBBStartIdx(MBB);
531 Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
532 if (MapItr != mi2iMap.end())
533 return MapItr->second;
537 /// getIndexAfter - Returns the index of the first indexed instruction
538 /// after MI, or the end index of its basic block.
539 /// MI is not required to have an index.
540 SlotIndex getIndexAfter(const MachineInstr *MI) const {
541 const MachineBasicBlock *MBB = MI->getParent();
542 assert(MBB && "MI must be inserted inna basic block");
543 MachineBasicBlock::const_iterator I = MI, E = MBB->end();
547 return getMBBEndIdx(MBB);
548 Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
549 if (MapItr != mi2iMap.end())
550 return MapItr->second;
554 /// Return the (start,end) range of the given basic block number.
555 const std::pair<SlotIndex, SlotIndex> &
556 getMBBRange(unsigned Num) const {
557 return MBBRanges[Num];
560 /// Return the (start,end) range of the given basic block.
561 const std::pair<SlotIndex, SlotIndex> &
562 getMBBRange(const MachineBasicBlock *MBB) const {
563 return getMBBRange(MBB->getNumber());
566 /// Returns the first index in the given basic block number.
567 SlotIndex getMBBStartIdx(unsigned Num) const {
568 return getMBBRange(Num).first;
571 /// Returns the first index in the given basic block.
572 SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
573 return getMBBRange(mbb).first;
576 /// Returns the last index in the given basic block number.
577 SlotIndex getMBBEndIdx(unsigned Num) const {
578 return getMBBRange(Num).second;
581 /// Returns the last index in the given basic block.
582 SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
583 return getMBBRange(mbb).second;
586 /// Returns the basic block which the given index falls in.
587 MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
588 if (MachineInstr *MI = getInstructionFromIndex(index))
589 return MI->getParent();
590 SmallVectorImpl<IdxMBBPair>::const_iterator I =
591 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), index);
592 // Take the pair containing the index
593 SmallVectorImpl<IdxMBBPair>::const_iterator J =
594 ((I != idx2MBBMap.end() && I->first > index) ||
595 (I == idx2MBBMap.end() && idx2MBBMap.size()>0)) ? (I-1): I;
597 assert(J != idx2MBBMap.end() && J->first <= index &&
598 index < getMBBEndIdx(J->second) &&
599 "index does not correspond to an MBB");
603 bool findLiveInMBBs(SlotIndex start, SlotIndex end,
604 SmallVectorImpl<MachineBasicBlock*> &mbbs) const {
605 SmallVectorImpl<IdxMBBPair>::const_iterator itr =
606 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
609 while (itr != idx2MBBMap.end()) {
610 if (itr->first >= end)
612 mbbs.push_back(itr->second);
619 /// Returns the MBB covering the given range, or null if the range covers
620 /// more than one basic block.
621 MachineBasicBlock* getMBBCoveringRange(SlotIndex start, SlotIndex end) const {
623 assert(start < end && "Backwards ranges not allowed.");
625 SmallVectorImpl<IdxMBBPair>::const_iterator itr =
626 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
628 if (itr == idx2MBBMap.end()) {
633 // Check that we don't cross the boundary into this block.
634 if (itr->first < end)
639 if (itr->first <= start)
645 /// Insert the given machine instruction into the mapping. Returns the
647 /// If Late is set and there are null indexes between mi's neighboring
648 /// instructions, create the new index after the null indexes instead of
650 SlotIndex insertMachineInstrInMaps(MachineInstr *mi, bool Late = false) {
651 assert(!mi->isInsideBundle() &&
652 "Instructions inside bundles should use bundle start's slot.");
653 assert(mi2iMap.find(mi) == mi2iMap.end() && "Instr already indexed.");
654 // Numbering DBG_VALUE instructions could cause code generation to be
655 // affected by debug information.
656 assert(!mi->isDebugValue() && "Cannot number DBG_VALUE instructions.");
658 assert(mi->getParent() != 0 && "Instr must be added to function.");
660 // Get the entries where mi should be inserted.
661 IndexListEntry *prevEntry, *nextEntry;
663 // Insert mi's index immediately before the following instruction.
664 nextEntry = &getIndexAfter(mi).entry();
665 prevEntry = nextEntry->getPrev();
667 // Insert mi's index immediately after the preceeding instruction.
668 prevEntry = &getIndexBefore(mi).entry();
669 nextEntry = prevEntry->getNext();
672 // Get a number for the new instr, or 0 if there's no room currently.
673 // In the latter case we'll force a renumber later.
674 unsigned dist = ((nextEntry->getIndex() - prevEntry->getIndex())/2) & ~3u;
675 unsigned newNumber = prevEntry->getIndex() + dist;
677 // Insert a new list entry for mi.
678 IndexListEntry *newEntry = createEntry(mi, newNumber);
679 insert(nextEntry, newEntry);
681 // Renumber locally if we need to.
683 renumberIndexes(newEntry);
685 SlotIndex newIndex(newEntry, SlotIndex::Slot_Block);
686 mi2iMap.insert(std::make_pair(mi, newIndex));
690 /// Remove the given machine instruction from the mapping.
691 void removeMachineInstrFromMaps(MachineInstr *mi) {
692 // remove index -> MachineInstr and
693 // MachineInstr -> index mappings
694 Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
695 if (mi2iItr != mi2iMap.end()) {
696 IndexListEntry *miEntry(&mi2iItr->second.entry());
697 assert(miEntry->getInstr() == mi && "Instruction indexes broken.");
698 // FIXME: Eventually we want to actually delete these indexes.
699 miEntry->setInstr(0);
700 mi2iMap.erase(mi2iItr);
704 /// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in
705 /// maps used by register allocator.
706 void replaceMachineInstrInMaps(MachineInstr *mi, MachineInstr *newMI) {
707 Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
708 if (mi2iItr == mi2iMap.end())
710 SlotIndex replaceBaseIndex = mi2iItr->second;
711 IndexListEntry *miEntry(&replaceBaseIndex.entry());
712 assert(miEntry->getInstr() == mi &&
713 "Mismatched instruction in index tables.");
714 miEntry->setInstr(newMI);
715 mi2iMap.erase(mi2iItr);
716 mi2iMap.insert(std::make_pair(newMI, replaceBaseIndex));
719 /// Add the given MachineBasicBlock into the maps.
720 void insertMBBInMaps(MachineBasicBlock *mbb) {
721 MachineFunction::iterator nextMBB =
722 llvm::next(MachineFunction::iterator(mbb));
723 IndexListEntry *startEntry = createEntry(0, 0);
724 IndexListEntry *stopEntry = createEntry(0, 0);
725 IndexListEntry *nextEntry = 0;
727 if (nextMBB == mbb->getParent()->end()) {
728 nextEntry = getTail();
730 nextEntry = &getMBBStartIdx(nextMBB).entry();
733 insert(nextEntry, startEntry);
734 insert(nextEntry, stopEntry);
736 SlotIndex startIdx(startEntry, SlotIndex::Slot_Block);
737 SlotIndex endIdx(nextEntry, SlotIndex::Slot_Block);
739 assert(unsigned(mbb->getNumber()) == MBBRanges.size() &&
740 "Blocks must be added in order");
741 MBBRanges.push_back(std::make_pair(startIdx, endIdx));
743 idx2MBBMap.push_back(IdxMBBPair(startIdx, mbb));
746 std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
752 // Specialize IntervalMapInfo for half-open slot index intervals.
753 template <typename> struct IntervalMapInfo;
754 template <> struct IntervalMapInfo<SlotIndex> {
755 static inline bool startLess(const SlotIndex &x, const SlotIndex &a) {
758 static inline bool stopLess(const SlotIndex &b, const SlotIndex &x) {
761 static inline bool adjacent(const SlotIndex &a, const SlotIndex &b) {
768 #endif // LLVM_CODEGEN_LIVEINDEX_H