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Diffstat (limited to 'include/llvm/CodeGen/SlotIndexes.h')
-rw-r--r-- | include/llvm/CodeGen/SlotIndexes.h | 740 |
1 files changed, 740 insertions, 0 deletions
diff --git a/include/llvm/CodeGen/SlotIndexes.h b/include/llvm/CodeGen/SlotIndexes.h new file mode 100644 index 0000000..3f175a7 --- /dev/null +++ b/include/llvm/CodeGen/SlotIndexes.h @@ -0,0 +1,740 @@ +//===- llvm/CodeGen/SlotIndexes.h - Slot indexes representation -*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file implements SlotIndex and related classes. The purpuse of SlotIndex +// is to describe a position at which a register can become live, or cease to +// be live. +// +// SlotIndex is mostly a proxy for entries of the SlotIndexList, a class which +// is held is LiveIntervals and provides the real numbering. This allows +// LiveIntervals to perform largely transparent renumbering. The SlotIndex +// class does hold a PHI bit, which determines whether the index relates to a +// PHI use or def point, or an actual instruction. See the SlotIndex class +// description for futher information. +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CODEGEN_SLOTINDEXES_H +#define LLVM_CODEGEN_SLOTINDEXES_H + +#include "llvm/ADT/PointerIntPair.h" +#include "llvm/ADT/SmallVector.h" +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineInstr.h" +#include "llvm/Support/Allocator.h" + +namespace llvm { + + /// This class represents an entry in the slot index list held in the + /// SlotIndexes pass. It should not be used directly. See the + /// SlotIndex & SlotIndexes classes for the public interface to this + /// information. + class IndexListEntry { + private: + + IndexListEntry *next, *prev; + MachineInstr *mi; + unsigned index; + + public: + + IndexListEntry(MachineInstr *mi, unsigned index) + : mi(mi), index(index) {} + + MachineInstr* getInstr() const { return mi; } + void setInstr(MachineInstr *mi) { this->mi = mi; } + + unsigned getIndex() const { return index; } + void setIndex(unsigned index) { this->index = index; } + + IndexListEntry* getNext() { return next; } + const IndexListEntry* getNext() const { return next; } + void setNext(IndexListEntry *next) { this->next = next; } + + IndexListEntry* getPrev() { return prev; } + const IndexListEntry* getPrev() const { return prev; } + void setPrev(IndexListEntry *prev) { this->prev = prev; } + }; + + // Specialize PointerLikeTypeTraits for IndexListEntry. + template <> + class PointerLikeTypeTraits<IndexListEntry*> { + public: + static inline void* getAsVoidPointer(IndexListEntry *p) { + return p; + } + static inline IndexListEntry* getFromVoidPointer(void *p) { + return static_cast<IndexListEntry*>(p); + } + enum { NumLowBitsAvailable = 3 }; + }; + + /// SlotIndex - An opaque wrapper around machine indexes. + class SlotIndex { + friend class SlotIndexes; + friend class DenseMapInfo<SlotIndex>; + + private: + + // FIXME: Is there any way to statically allocate these things and have + // them 8-byte aligned? + static std::auto_ptr<IndexListEntry> emptyKeyPtr, tombstoneKeyPtr; + static const unsigned PHI_BIT = 1 << 2; + + PointerIntPair<IndexListEntry*, 3, unsigned> lie; + + SlotIndex(IndexListEntry *entry, unsigned phiAndSlot) + : lie(entry, phiAndSlot) { + assert(entry != 0 && "Attempt to construct index with 0 pointer."); + } + + IndexListEntry& entry() const { + assert(lie.getPointer() != 0 && "Use of invalid index."); + return *lie.getPointer(); + } + + int getIndex() const { + return entry().getIndex() | getSlot(); + } + + static inline unsigned getHashValue(const SlotIndex &v) { + IndexListEntry *ptrVal = &v.entry(); + return (unsigned((intptr_t)ptrVal) >> 4) ^ + (unsigned((intptr_t)ptrVal) >> 9); + } + + public: + + // FIXME: Ugh. This is public because LiveIntervalAnalysis is still using it + // for some spill weight stuff. Fix that, then make this private. + enum Slot { LOAD, USE, DEF, STORE, NUM }; + + static inline SlotIndex getEmptyKey() { + // FIXME: How do we guarantee these numbers don't get allocated to + // legit indexes? + if (emptyKeyPtr.get() == 0) + emptyKeyPtr.reset(new IndexListEntry(0, ~0U & ~3U)); + + return SlotIndex(emptyKeyPtr.get(), 0); + } + + static inline SlotIndex getTombstoneKey() { + // FIXME: How do we guarantee these numbers don't get allocated to + // legit indexes? + if (tombstoneKeyPtr.get() == 0) + tombstoneKeyPtr.reset(new IndexListEntry(0, ~0U & ~7U)); + + return SlotIndex(tombstoneKeyPtr.get(), 0); + } + + /// Construct an invalid index. + SlotIndex() : lie(&getEmptyKey().entry(), 0) {} + + // Construct a new slot index from the given one, set the phi flag on the + // new index to the value of the phi parameter. + SlotIndex(const SlotIndex &li, bool phi) + : lie(&li.entry(), phi ? PHI_BIT & li.getSlot() : (unsigned)li.getSlot()){ + assert(lie.getPointer() != 0 && + "Attempt to construct index with 0 pointer."); + } + + // Construct a new slot index from the given one, set the phi flag on the + // new index to the value of the phi parameter, and the slot to the new slot. + SlotIndex(const SlotIndex &li, bool phi, Slot s) + : lie(&li.entry(), phi ? PHI_BIT & s : (unsigned)s) { + assert(lie.getPointer() != 0 && + "Attempt to construct index with 0 pointer."); + } + + /// Returns true if this is a valid index. Invalid indicies do + /// not point into an index table, and cannot be compared. + bool isValid() const { + return (lie.getPointer() != 0) && (lie.getPointer()->getIndex() != 0); + } + + /// Print this index to the given raw_ostream. + void print(raw_ostream &os) const; + + /// Dump this index to stderr. + void dump() const; + + /// Compare two SlotIndex objects for equality. + bool operator==(SlotIndex other) const { + return getIndex() == other.getIndex(); + } + /// Compare two SlotIndex objects for inequality. + bool operator!=(SlotIndex other) const { + return getIndex() != other.getIndex(); + } + + /// Compare two SlotIndex objects. Return true if the first index + /// is strictly lower than the second. + bool operator<(SlotIndex other) const { + return getIndex() < other.getIndex(); + } + /// Compare two SlotIndex objects. Return true if the first index + /// is lower than, or equal to, the second. + bool operator<=(SlotIndex other) const { + return getIndex() <= other.getIndex(); + } + + /// Compare two SlotIndex objects. Return true if the first index + /// is greater than the second. + bool operator>(SlotIndex other) const { + return getIndex() > other.getIndex(); + } + + /// Compare two SlotIndex objects. Return true if the first index + /// is greater than, or equal to, the second. + bool operator>=(SlotIndex other) const { + return getIndex() >= other.getIndex(); + } + + /// Return the distance from this index to the given one. + int distance(SlotIndex other) const { + return other.getIndex() - getIndex(); + } + + /// Returns the slot for this SlotIndex. + Slot getSlot() const { + return static_cast<Slot>(lie.getInt() & ~PHI_BIT); + } + + /// Returns the state of the PHI bit. + bool isPHI() const { + return lie.getInt() & PHI_BIT; + } + + /// Returns the base index for associated with this index. The base index + /// is the one associated with the LOAD slot for the instruction pointed to + /// by this index. + SlotIndex getBaseIndex() const { + return getLoadIndex(); + } + + /// Returns the boundary index for associated with this index. The boundary + /// index is the one associated with the LOAD slot for the instruction + /// pointed to by this index. + SlotIndex getBoundaryIndex() const { + return getStoreIndex(); + } + + /// Returns the index of the LOAD slot for the instruction pointed to by + /// this index. + SlotIndex getLoadIndex() const { + return SlotIndex(&entry(), SlotIndex::LOAD); + } + + /// Returns the index of the USE slot for the instruction pointed to by + /// this index. + SlotIndex getUseIndex() const { + return SlotIndex(&entry(), SlotIndex::USE); + } + + /// Returns the index of the DEF slot for the instruction pointed to by + /// this index. + SlotIndex getDefIndex() const { + return SlotIndex(&entry(), SlotIndex::DEF); + } + + /// Returns the index of the STORE slot for the instruction pointed to by + /// this index. + SlotIndex getStoreIndex() const { + return SlotIndex(&entry(), SlotIndex::STORE); + } + + /// Returns the next slot in the index list. This could be either the + /// next slot for the instruction pointed to by this index or, if this + /// index is a STORE, the first slot for the next instruction. + /// WARNING: This method is considerably more expensive than the methods + /// that return specific slots (getUseIndex(), etc). If you can - please + /// use one of those methods. + SlotIndex getNextSlot() const { + Slot s = getSlot(); + if (s == SlotIndex::STORE) { + return SlotIndex(entry().getNext(), SlotIndex::LOAD); + } + return SlotIndex(&entry(), s + 1); + } + + /// Returns the next index. This is the index corresponding to the this + /// index's slot, but for the next instruction. + SlotIndex getNextIndex() const { + return SlotIndex(entry().getNext(), getSlot()); + } + + /// Returns the previous slot in the index list. This could be either the + /// previous slot for the instruction pointed to by this index or, if this + /// index is a LOAD, the last slot for the previous instruction. + /// WARNING: This method is considerably more expensive than the methods + /// that return specific slots (getUseIndex(), etc). If you can - please + /// use one of those methods. + SlotIndex getPrevSlot() const { + Slot s = getSlot(); + if (s == SlotIndex::LOAD) { + return SlotIndex(entry().getPrev(), SlotIndex::STORE); + } + return SlotIndex(&entry(), s - 1); + } + + /// Returns the previous index. This is the index corresponding to this + /// index's slot, but for the previous instruction. + SlotIndex getPrevIndex() const { + return SlotIndex(entry().getPrev(), getSlot()); + } + + }; + + /// DenseMapInfo specialization for SlotIndex. + template <> + struct DenseMapInfo<SlotIndex> { + static inline SlotIndex getEmptyKey() { + return SlotIndex::getEmptyKey(); + } + static inline SlotIndex getTombstoneKey() { + return SlotIndex::getTombstoneKey(); + } + static inline unsigned getHashValue(const SlotIndex &v) { + return SlotIndex::getHashValue(v); + } + static inline bool isEqual(const SlotIndex &LHS, const SlotIndex &RHS) { + return (LHS == RHS); + } + static inline bool isPod() { return false; } + }; + + inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) { + li.print(os); + return os; + } + + typedef std::pair<SlotIndex, MachineBasicBlock*> IdxMBBPair; + + inline bool operator<(SlotIndex V, const IdxMBBPair &IM) { + return V < IM.first; + } + + inline bool operator<(const IdxMBBPair &IM, SlotIndex V) { + return IM.first < V; + } + + struct Idx2MBBCompare { + bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const { + return LHS.first < RHS.first; + } + }; + + /// SlotIndexes pass. + /// + /// This pass assigns indexes to each instruction. + class SlotIndexes : public MachineFunctionPass { + private: + + MachineFunction *mf; + IndexListEntry *indexListHead; + unsigned functionSize; + + typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap; + Mi2IndexMap mi2iMap; + + /// MBB2IdxMap - The indexes of the first and last instructions in the + /// specified basic block. + typedef DenseMap<const MachineBasicBlock*, + std::pair<SlotIndex, SlotIndex> > MBB2IdxMap; + MBB2IdxMap mbb2IdxMap; + + /// Idx2MBBMap - Sorted list of pairs of index of first instruction + /// and MBB id. + std::vector<IdxMBBPair> idx2MBBMap; + + typedef DenseMap<const MachineBasicBlock*, SlotIndex> TerminatorGapsMap; + TerminatorGapsMap terminatorGaps; + + // IndexListEntry allocator. + BumpPtrAllocator ileAllocator; + + IndexListEntry* createEntry(MachineInstr *mi, unsigned index) { + IndexListEntry *entry = + static_cast<IndexListEntry*>( + ileAllocator.Allocate(sizeof(IndexListEntry), + alignof<IndexListEntry>())); + + new (entry) IndexListEntry(mi, index); + + return entry; + } + + void initList() { + assert(indexListHead == 0 && "Zero entry non-null at initialisation."); + indexListHead = createEntry(0, ~0U); + indexListHead->setNext(0); + indexListHead->setPrev(indexListHead); + } + + void clearList() { + indexListHead = 0; + ileAllocator.Reset(); + } + + IndexListEntry* getTail() { + assert(indexListHead != 0 && "Call to getTail on uninitialized list."); + return indexListHead->getPrev(); + } + + const IndexListEntry* getTail() const { + assert(indexListHead != 0 && "Call to getTail on uninitialized list."); + return indexListHead->getPrev(); + } + + // Returns true if the index list is empty. + bool empty() const { return (indexListHead == getTail()); } + + IndexListEntry* front() { + assert(!empty() && "front() called on empty index list."); + return indexListHead; + } + + const IndexListEntry* front() const { + assert(!empty() && "front() called on empty index list."); + return indexListHead; + } + + IndexListEntry* back() { + assert(!empty() && "back() called on empty index list."); + return getTail()->getPrev(); + } + + const IndexListEntry* back() const { + assert(!empty() && "back() called on empty index list."); + return getTail()->getPrev(); + } + + /// Insert a new entry before itr. + void insert(IndexListEntry *itr, IndexListEntry *val) { + assert(itr != 0 && "itr should not be null."); + IndexListEntry *prev = itr->getPrev(); + val->setNext(itr); + val->setPrev(prev); + + if (itr != indexListHead) { + prev->setNext(val); + } + else { + indexListHead = val; + } + itr->setPrev(val); + } + + /// Push a new entry on to the end of the list. + void push_back(IndexListEntry *val) { + insert(getTail(), val); + } + + public: + static char ID; + + SlotIndexes() : MachineFunctionPass(&ID), indexListHead(0) {} + + virtual void getAnalysisUsage(AnalysisUsage &au) const; + virtual void releaseMemory(); + + virtual bool runOnMachineFunction(MachineFunction &fn); + + /// Dump the indexes. + void dump() const; + + /// Renumber the index list, providing space for new instructions. + void renumber(); + + /// Returns the zero index for this analysis. + SlotIndex getZeroIndex() { + assert(front()->getIndex() == 0 && "First index is not 0?"); + return SlotIndex(front(), 0); + } + + /// Returns the invalid index marker for this analysis. + SlotIndex getInvalidIndex() { + return getZeroIndex(); + } + + /// Returns the distance between the highest and lowest indexes allocated + /// so far. + unsigned getIndexesLength() const { + assert(front()->getIndex() == 0 && + "Initial index isn't zero?"); + + return back()->getIndex(); + } + + /// Returns the number of instructions in the function. + unsigned getFunctionSize() const { + return functionSize; + } + + /// Returns true if the given machine instr is mapped to an index, + /// otherwise returns false. + bool hasIndex(const MachineInstr *instr) const { + return (mi2iMap.find(instr) != mi2iMap.end()); + } + + /// Returns the base index for the given instruction. + SlotIndex getInstructionIndex(const MachineInstr *instr) const { + Mi2IndexMap::const_iterator itr = mi2iMap.find(instr); + assert(itr != mi2iMap.end() && "Instruction not found in maps."); + return itr->second; + } + + /// Returns the instruction for the given index, or null if the given + /// index has no instruction associated with it. + MachineInstr* getInstructionFromIndex(SlotIndex index) const { + return index.entry().getInstr(); + } + + /// Returns the next non-null index. + SlotIndex getNextNonNullIndex(SlotIndex index) { + SlotIndex nextNonNull = index.getNextIndex(); + + while (&nextNonNull.entry() != getTail() && + getInstructionFromIndex(nextNonNull) == 0) { + nextNonNull = nextNonNull.getNextIndex(); + } + + return nextNonNull; + } + + /// Returns the first index in the given basic block. + SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const { + MBB2IdxMap::const_iterator itr = mbb2IdxMap.find(mbb); + assert(itr != mbb2IdxMap.end() && "MBB not found in maps."); + return itr->second.first; + } + + /// Returns the last index in the given basic block. + SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const { + MBB2IdxMap::const_iterator itr = mbb2IdxMap.find(mbb); + assert(itr != mbb2IdxMap.end() && "MBB not found in maps."); + return itr->second.second; + } + + /// Returns the terminator gap for the given index. + SlotIndex getTerminatorGap(const MachineBasicBlock *mbb) { + TerminatorGapsMap::iterator itr = terminatorGaps.find(mbb); + assert(itr != terminatorGaps.end() && + "All MBBs should have terminator gaps in their indexes."); + return itr->second; + } + + /// Returns the basic block which the given index falls in. + MachineBasicBlock* getMBBFromIndex(SlotIndex index) const { + std::vector<IdxMBBPair>::const_iterator I = + std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), index); + // Take the pair containing the index + std::vector<IdxMBBPair>::const_iterator J = + ((I != idx2MBBMap.end() && I->first > index) || + (I == idx2MBBMap.end() && idx2MBBMap.size()>0)) ? (I-1): I; + + assert(J != idx2MBBMap.end() && J->first <= index && + index <= getMBBEndIdx(J->second) && + "index does not correspond to an MBB"); + return J->second; + } + + bool findLiveInMBBs(SlotIndex start, SlotIndex end, + SmallVectorImpl<MachineBasicBlock*> &mbbs) const { + std::vector<IdxMBBPair>::const_iterator itr = + std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start); + bool resVal = false; + + while (itr != idx2MBBMap.end()) { + if (itr->first >= end) + break; + mbbs.push_back(itr->second); + resVal = true; + ++itr; + } + return resVal; + } + + /// Return a list of MBBs that can be reach via any branches or + /// fall-throughs. + bool findReachableMBBs(SlotIndex start, SlotIndex end, + SmallVectorImpl<MachineBasicBlock*> &mbbs) const { + std::vector<IdxMBBPair>::const_iterator itr = + std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start); + + bool resVal = false; + while (itr != idx2MBBMap.end()) { + if (itr->first > end) + break; + MachineBasicBlock *mbb = itr->second; + if (getMBBEndIdx(mbb) > end) + break; + for (MachineBasicBlock::succ_iterator si = mbb->succ_begin(), + se = mbb->succ_end(); si != se; ++si) + mbbs.push_back(*si); + resVal = true; + ++itr; + } + return resVal; + } + + /// Returns the MBB covering the given range, or null if the range covers + /// more than one basic block. + MachineBasicBlock* getMBBCoveringRange(SlotIndex start, SlotIndex end) const { + + assert(start < end && "Backwards ranges not allowed."); + + std::vector<IdxMBBPair>::const_iterator itr = + std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start); + + if (itr == idx2MBBMap.end()) { + itr = prior(itr); + return itr->second; + } + + // Check that we don't cross the boundary into this block. + if (itr->first < end) + return 0; + + itr = prior(itr); + + if (itr->first <= start) + return itr->second; + + return 0; + } + + /// Returns true if there is a gap in the numbering before the given index. + bool hasGapBeforeInstr(SlotIndex index) { + index = index.getBaseIndex(); + SlotIndex prevIndex = index.getPrevIndex(); + + if (prevIndex == getZeroIndex()) + return false; + + if (getInstructionFromIndex(prevIndex) == 0) + return true; + + if (prevIndex.distance(index) >= 2 * SlotIndex::NUM) + return true; + + return false; + } + + /// Returns true if there is a gap in the numbering after the given index. + bool hasGapAfterInstr(SlotIndex index) const { + // Not implemented yet. + assert(false && + "SlotIndexes::hasGapAfterInstr(SlotIndex) not implemented yet."); + return false; + } + + /// findGapBeforeInstr - Find an empty instruction slot before the + /// specified index. If "Furthest" is true, find one that's furthest + /// away from the index (but before any index that's occupied). + // FIXME: This whole method should go away in future. It should + // always be possible to insert code between existing indices. + SlotIndex findGapBeforeInstr(SlotIndex index, bool furthest = false) { + if (index == getZeroIndex()) + return getInvalidIndex(); + + index = index.getBaseIndex(); + SlotIndex prevIndex = index.getPrevIndex(); + + if (prevIndex == getZeroIndex()) + return getInvalidIndex(); + + // Try to reuse existing index objects with null-instrs. + if (getInstructionFromIndex(prevIndex) == 0) { + if (furthest) { + while (getInstructionFromIndex(prevIndex) == 0 && + prevIndex != getZeroIndex()) { + prevIndex = prevIndex.getPrevIndex(); + } + + prevIndex = prevIndex.getNextIndex(); + } + + assert(getInstructionFromIndex(prevIndex) == 0 && "Index list is broken."); + + return prevIndex; + } + + int dist = prevIndex.distance(index); + + // Double check that the spacing between this instruction and + // the last is sane. + assert(dist >= SlotIndex::NUM && + "Distance between indexes too small."); + + // If there's no gap return an invalid index. + if (dist < 2*SlotIndex::NUM) { + return getInvalidIndex(); + } + + // Otherwise insert new index entries into the list using the + // gap in the numbering. + IndexListEntry *newEntry = + createEntry(0, prevIndex.entry().getIndex() + SlotIndex::NUM); + + insert(&index.entry(), newEntry); + + // And return a pointer to the entry at the start of the gap. + return index.getPrevIndex(); + } + + /// Insert the given machine instruction into the mapping at the given + /// index. + void insertMachineInstrInMaps(MachineInstr *mi, SlotIndex index) { + index = index.getBaseIndex(); + IndexListEntry *miEntry = &index.entry(); + assert(miEntry->getInstr() == 0 && "Index already in use."); + miEntry->setInstr(mi); + + assert(mi2iMap.find(mi) == mi2iMap.end() && + "MachineInstr already has an index."); + + mi2iMap.insert(std::make_pair(mi, index)); + } + + /// Remove the given machine instruction from the mapping. + void removeMachineInstrFromMaps(MachineInstr *mi) { + // remove index -> MachineInstr and + // MachineInstr -> index mappings + Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi); + if (mi2iItr != mi2iMap.end()) { + IndexListEntry *miEntry(&mi2iItr->second.entry()); + assert(miEntry->getInstr() == mi && "Instruction indexes broken."); + // FIXME: Eventually we want to actually delete these indexes. + miEntry->setInstr(0); + mi2iMap.erase(mi2iItr); + } + } + + /// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in + /// maps used by register allocator. + void replaceMachineInstrInMaps(MachineInstr *mi, MachineInstr *newMI) { + Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi); + if (mi2iItr == mi2iMap.end()) + return; + SlotIndex replaceBaseIndex = mi2iItr->second; + IndexListEntry *miEntry(&replaceBaseIndex.entry()); + assert(miEntry->getInstr() == mi && + "Mismatched instruction in index tables."); + miEntry->setInstr(newMI); + mi2iMap.erase(mi2iItr); + mi2iMap.insert(std::make_pair(newMI, replaceBaseIndex)); + } + + }; + + +} + +#endif // LLVM_CODEGEN_LIVEINDEX_H |