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 /// Return the distance from this index to the given one.
212 int distance(SlotIndex other) const {
213 return other.getIndex() - getIndex();
216 /// isBlock - Returns true if this is a block boundary slot.
217 bool isBlock() const { return getSlot() == Slot_Block; }
219 /// isEarlyClobber - Returns true if this is an early-clobber slot.
220 bool isEarlyClobber() const { return getSlot() == Slot_EarlyClobber; }
222 /// isRegister - Returns true if this is a normal register use/def slot.
223 /// Note that early-clobber slots may also be used for uses and defs.
224 bool isRegister() const { return getSlot() == Slot_Register; }
226 /// isDead - Returns true if this is a dead def kill slot.
227 bool isDead() const { return getSlot() == Slot_Dead; }
229 /// Returns the base index for associated with this index. The base index
230 /// is the one associated with the Slot_Block slot for the instruction
231 /// pointed to by this index.
232 SlotIndex getBaseIndex() const {
233 return SlotIndex(&entry(), Slot_Block);
236 /// Returns the boundary index for associated with this index. The boundary
237 /// index is the one associated with the Slot_Block slot for the instruction
238 /// pointed to by this index.
239 SlotIndex getBoundaryIndex() const {
240 return SlotIndex(&entry(), Slot_Dead);
243 /// Returns the register use/def slot in the current instruction for a
244 /// normal or early-clobber def.
245 SlotIndex getRegSlot(bool EC = false) const {
246 return SlotIndex(&entry(), EC ? Slot_EarlyClobber : Slot_Register);
249 /// Returns the dead def kill slot for the current instruction.
250 SlotIndex getDeadSlot() const {
251 return SlotIndex(&entry(), Slot_Dead);
254 /// Returns the next slot in the index list. This could be either the
255 /// next slot for the instruction pointed to by this index or, if this
256 /// index is a STORE, the first slot for the next instruction.
257 /// WARNING: This method is considerably more expensive than the methods
258 /// that return specific slots (getUseIndex(), etc). If you can - please
259 /// use one of those methods.
260 SlotIndex getNextSlot() const {
262 if (s == Slot_Dead) {
263 return SlotIndex(entry().getNext(), Slot_Block);
265 return SlotIndex(&entry(), s + 1);
268 /// Returns the next index. This is the index corresponding to the this
269 /// index's slot, but for the next instruction.
270 SlotIndex getNextIndex() const {
271 return SlotIndex(entry().getNext(), getSlot());
274 /// Returns the previous slot in the index list. This could be either the
275 /// previous slot for the instruction pointed to by this index or, if this
276 /// index is a Slot_Block, the last slot for the previous instruction.
277 /// WARNING: This method is considerably more expensive than the methods
278 /// that return specific slots (getUseIndex(), etc). If you can - please
279 /// use one of those methods.
280 SlotIndex getPrevSlot() const {
282 if (s == Slot_Block) {
283 return SlotIndex(entry().getPrev(), Slot_Dead);
285 return SlotIndex(&entry(), s - 1);
288 /// Returns the previous index. This is the index corresponding to this
289 /// index's slot, but for the previous instruction.
290 SlotIndex getPrevIndex() const {
291 return SlotIndex(entry().getPrev(), getSlot());
296 /// DenseMapInfo specialization for SlotIndex.
298 struct DenseMapInfo<SlotIndex> {
299 static inline SlotIndex getEmptyKey() {
300 return SlotIndex::getEmptyKey();
302 static inline SlotIndex getTombstoneKey() {
303 return SlotIndex::getTombstoneKey();
305 static inline unsigned getHashValue(const SlotIndex &v) {
306 return SlotIndex::getHashValue(v);
308 static inline bool isEqual(const SlotIndex &LHS, const SlotIndex &RHS) {
313 template <> struct isPodLike<SlotIndex> { static const bool value = true; };
316 inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
321 typedef std::pair<SlotIndex, MachineBasicBlock*> IdxMBBPair;
323 inline bool operator<(SlotIndex V, const IdxMBBPair &IM) {
327 inline bool operator<(const IdxMBBPair &IM, SlotIndex V) {
331 struct Idx2MBBCompare {
332 bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
333 return LHS.first < RHS.first;
337 /// SlotIndexes pass.
339 /// This pass assigns indexes to each instruction.
340 class SlotIndexes : public MachineFunctionPass {
344 IndexListEntry *indexListHead;
345 unsigned functionSize;
347 typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap;
350 /// MBBRanges - Map MBB number to (start, stop) indexes.
351 SmallVector<std::pair<SlotIndex, SlotIndex>, 8> MBBRanges;
353 /// Idx2MBBMap - Sorted list of pairs of index of first instruction
355 SmallVector<IdxMBBPair, 8> idx2MBBMap;
357 // IndexListEntry allocator.
358 BumpPtrAllocator ileAllocator;
360 IndexListEntry* createEntry(MachineInstr *mi, unsigned index) {
361 IndexListEntry *entry =
362 static_cast<IndexListEntry*>(
363 ileAllocator.Allocate(sizeof(IndexListEntry),
364 alignOf<IndexListEntry>()));
366 new (entry) IndexListEntry(mi, index);
372 assert(indexListHead == 0 && "Zero entry non-null at initialisation.");
373 indexListHead = createEntry(0, ~0U);
374 indexListHead->setNext(0);
375 indexListHead->setPrev(indexListHead);
380 ileAllocator.Reset();
383 IndexListEntry* getTail() {
384 assert(indexListHead != 0 && "Call to getTail on uninitialized list.");
385 return indexListHead->getPrev();
388 const IndexListEntry* getTail() const {
389 assert(indexListHead != 0 && "Call to getTail on uninitialized list.");
390 return indexListHead->getPrev();
393 // Returns true if the index list is empty.
394 bool empty() const { return (indexListHead == getTail()); }
396 IndexListEntry* front() {
397 assert(!empty() && "front() called on empty index list.");
398 return indexListHead;
401 const IndexListEntry* front() const {
402 assert(!empty() && "front() called on empty index list.");
403 return indexListHead;
406 IndexListEntry* back() {
407 assert(!empty() && "back() called on empty index list.");
408 return getTail()->getPrev();
411 const IndexListEntry* back() const {
412 assert(!empty() && "back() called on empty index list.");
413 return getTail()->getPrev();
416 /// Insert a new entry before itr.
417 void insert(IndexListEntry *itr, IndexListEntry *val) {
418 assert(itr != 0 && "itr should not be null.");
419 IndexListEntry *prev = itr->getPrev();
423 if (itr != indexListHead) {
432 /// Push a new entry on to the end of the list.
433 void push_back(IndexListEntry *val) {
434 insert(getTail(), val);
437 /// Renumber locally after inserting newEntry.
438 void renumberIndexes(IndexListEntry *newEntry);
443 SlotIndexes() : MachineFunctionPass(ID), indexListHead(0) {
444 initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
447 virtual void getAnalysisUsage(AnalysisUsage &au) const;
448 virtual void releaseMemory();
450 virtual bool runOnMachineFunction(MachineFunction &fn);
452 /// Dump the indexes.
455 /// Renumber the index list, providing space for new instructions.
456 void renumberIndexes();
458 /// Returns the zero index for this analysis.
459 SlotIndex getZeroIndex() {
460 assert(front()->getIndex() == 0 && "First index is not 0?");
461 return SlotIndex(front(), 0);
464 /// Returns the base index of the last slot in this analysis.
465 SlotIndex getLastIndex() {
466 return SlotIndex(back(), 0);
469 /// Returns the invalid index marker for this analysis.
470 SlotIndex getInvalidIndex() {
471 return getZeroIndex();
474 /// Returns the distance between the highest and lowest indexes allocated
476 unsigned getIndexesLength() const {
477 assert(front()->getIndex() == 0 &&
478 "Initial index isn't zero?");
480 return back()->getIndex();
483 /// Returns the number of instructions in the function.
484 unsigned getFunctionSize() const {
488 /// Returns true if the given machine instr is mapped to an index,
489 /// otherwise returns false.
490 bool hasIndex(const MachineInstr *instr) const {
491 return (mi2iMap.find(instr) != mi2iMap.end());
494 /// Returns the base index for the given instruction.
495 SlotIndex getInstructionIndex(const MachineInstr *instr) const {
496 Mi2IndexMap::const_iterator itr = mi2iMap.find(instr);
497 assert(itr != mi2iMap.end() && "Instruction not found in maps.");
501 /// Returns the instruction for the given index, or null if the given
502 /// index has no instruction associated with it.
503 MachineInstr* getInstructionFromIndex(SlotIndex index) const {
504 return index.isValid() ? index.entry().getInstr() : 0;
507 /// Returns the next non-null index.
508 SlotIndex getNextNonNullIndex(SlotIndex index) {
509 SlotIndex nextNonNull = index.getNextIndex();
511 while (&nextNonNull.entry() != getTail() &&
512 getInstructionFromIndex(nextNonNull) == 0) {
513 nextNonNull = nextNonNull.getNextIndex();
519 /// getIndexBefore - Returns the index of the last indexed instruction
520 /// before MI, or the the start index of its basic block.
521 /// MI is not required to have an index.
522 SlotIndex getIndexBefore(const MachineInstr *MI) const {
523 const MachineBasicBlock *MBB = MI->getParent();
524 assert(MBB && "MI must be inserted inna basic block");
525 MachineBasicBlock::const_iterator I = MI, B = MBB->begin();
528 return getMBBStartIdx(MBB);
530 Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
531 if (MapItr != mi2iMap.end())
532 return MapItr->second;
536 /// getIndexAfter - Returns the index of the first indexed instruction
537 /// after MI, or the end index of its basic block.
538 /// MI is not required to have an index.
539 SlotIndex getIndexAfter(const MachineInstr *MI) const {
540 const MachineBasicBlock *MBB = MI->getParent();
541 assert(MBB && "MI must be inserted inna basic block");
542 MachineBasicBlock::const_iterator I = MI, E = MBB->end();
546 return getMBBEndIdx(MBB);
547 Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
548 if (MapItr != mi2iMap.end())
549 return MapItr->second;
553 /// Return the (start,end) range of the given basic block number.
554 const std::pair<SlotIndex, SlotIndex> &
555 getMBBRange(unsigned Num) const {
556 return MBBRanges[Num];
559 /// Return the (start,end) range of the given basic block.
560 const std::pair<SlotIndex, SlotIndex> &
561 getMBBRange(const MachineBasicBlock *MBB) const {
562 return getMBBRange(MBB->getNumber());
565 /// Returns the first index in the given basic block number.
566 SlotIndex getMBBStartIdx(unsigned Num) const {
567 return getMBBRange(Num).first;
570 /// Returns the first index in the given basic block.
571 SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
572 return getMBBRange(mbb).first;
575 /// Returns the last index in the given basic block number.
576 SlotIndex getMBBEndIdx(unsigned Num) const {
577 return getMBBRange(Num).second;
580 /// Returns the last index in the given basic block.
581 SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
582 return getMBBRange(mbb).second;
585 /// Returns the basic block which the given index falls in.
586 MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
587 if (MachineInstr *MI = getInstructionFromIndex(index))
588 return MI->getParent();
589 SmallVectorImpl<IdxMBBPair>::const_iterator I =
590 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), index);
591 // Take the pair containing the index
592 SmallVectorImpl<IdxMBBPair>::const_iterator J =
593 ((I != idx2MBBMap.end() && I->first > index) ||
594 (I == idx2MBBMap.end() && idx2MBBMap.size()>0)) ? (I-1): I;
596 assert(J != idx2MBBMap.end() && J->first <= index &&
597 index < getMBBEndIdx(J->second) &&
598 "index does not correspond to an MBB");
602 bool findLiveInMBBs(SlotIndex start, SlotIndex end,
603 SmallVectorImpl<MachineBasicBlock*> &mbbs) const {
604 SmallVectorImpl<IdxMBBPair>::const_iterator itr =
605 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
608 while (itr != idx2MBBMap.end()) {
609 if (itr->first >= end)
611 mbbs.push_back(itr->second);
618 /// Returns the MBB covering the given range, or null if the range covers
619 /// more than one basic block.
620 MachineBasicBlock* getMBBCoveringRange(SlotIndex start, SlotIndex end) const {
622 assert(start < end && "Backwards ranges not allowed.");
624 SmallVectorImpl<IdxMBBPair>::const_iterator itr =
625 std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
627 if (itr == idx2MBBMap.end()) {
632 // Check that we don't cross the boundary into this block.
633 if (itr->first < end)
638 if (itr->first <= start)
644 /// Insert the given machine instruction into the mapping. Returns the
646 /// If Late is set and there are null indexes between mi's neighboring
647 /// instructions, create the new index after the null indexes instead of
649 SlotIndex insertMachineInstrInMaps(MachineInstr *mi, bool Late = false) {
650 assert(mi2iMap.find(mi) == mi2iMap.end() && "Instr already indexed.");
651 // Numbering DBG_VALUE instructions could cause code generation to be
652 // affected by debug information.
653 assert(!mi->isDebugValue() && "Cannot number DBG_VALUE instructions.");
655 assert(mi->getParent() != 0 && "Instr must be added to function.");
657 // Get the entries where mi should be inserted.
658 IndexListEntry *prevEntry, *nextEntry;
660 // Insert mi's index immediately before the following instruction.
661 nextEntry = &getIndexAfter(mi).entry();
662 prevEntry = nextEntry->getPrev();
664 // Insert mi's index immediately after the preceeding instruction.
665 prevEntry = &getIndexBefore(mi).entry();
666 nextEntry = prevEntry->getNext();
669 // Get a number for the new instr, or 0 if there's no room currently.
670 // In the latter case we'll force a renumber later.
671 unsigned dist = ((nextEntry->getIndex() - prevEntry->getIndex())/2) & ~3u;
672 unsigned newNumber = prevEntry->getIndex() + dist;
674 // Insert a new list entry for mi.
675 IndexListEntry *newEntry = createEntry(mi, newNumber);
676 insert(nextEntry, newEntry);
678 // Renumber locally if we need to.
680 renumberIndexes(newEntry);
682 SlotIndex newIndex(newEntry, SlotIndex::Slot_Block);
683 mi2iMap.insert(std::make_pair(mi, newIndex));
687 /// Remove the given machine instruction from the mapping.
688 void removeMachineInstrFromMaps(MachineInstr *mi) {
689 // remove index -> MachineInstr and
690 // MachineInstr -> index mappings
691 Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
692 if (mi2iItr != mi2iMap.end()) {
693 IndexListEntry *miEntry(&mi2iItr->second.entry());
694 assert(miEntry->getInstr() == mi && "Instruction indexes broken.");
695 // FIXME: Eventually we want to actually delete these indexes.
696 miEntry->setInstr(0);
697 mi2iMap.erase(mi2iItr);
701 /// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in
702 /// maps used by register allocator.
703 void replaceMachineInstrInMaps(MachineInstr *mi, MachineInstr *newMI) {
704 Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
705 if (mi2iItr == mi2iMap.end())
707 SlotIndex replaceBaseIndex = mi2iItr->second;
708 IndexListEntry *miEntry(&replaceBaseIndex.entry());
709 assert(miEntry->getInstr() == mi &&
710 "Mismatched instruction in index tables.");
711 miEntry->setInstr(newMI);
712 mi2iMap.erase(mi2iItr);
713 mi2iMap.insert(std::make_pair(newMI, replaceBaseIndex));
716 /// Add the given MachineBasicBlock into the maps.
717 void insertMBBInMaps(MachineBasicBlock *mbb) {
718 MachineFunction::iterator nextMBB =
719 llvm::next(MachineFunction::iterator(mbb));
720 IndexListEntry *startEntry = createEntry(0, 0);
721 IndexListEntry *stopEntry = createEntry(0, 0);
722 IndexListEntry *nextEntry = 0;
724 if (nextMBB == mbb->getParent()->end()) {
725 nextEntry = getTail();
727 nextEntry = &getMBBStartIdx(nextMBB).entry();
730 insert(nextEntry, startEntry);
731 insert(nextEntry, stopEntry);
733 SlotIndex startIdx(startEntry, SlotIndex::Slot_Block);
734 SlotIndex endIdx(nextEntry, SlotIndex::Slot_Block);
736 assert(unsigned(mbb->getNumber()) == MBBRanges.size() &&
737 "Blocks must be added in order");
738 MBBRanges.push_back(std::make_pair(startIdx, endIdx));
740 idx2MBBMap.push_back(IdxMBBPair(startIdx, mbb));
743 std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
749 // Specialize IntervalMapInfo for half-open slot index intervals.
750 template <typename> struct IntervalMapInfo;
751 template <> struct IntervalMapInfo<SlotIndex> {
752 static inline bool startLess(const SlotIndex &x, const SlotIndex &a) {
755 static inline bool stopLess(const SlotIndex &b, const SlotIndex &x) {
758 static inline bool adjacent(const SlotIndex &a, const SlotIndex &b) {
765 #endif // LLVM_CODEGEN_LIVEINDEX_H