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|
//===- 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"
#include "llvm/Support/ErrorHandling.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:
static const unsigned EMPTY_KEY_INDEX = ~0U & ~3U,
TOMBSTONE_KEY_INDEX = ~0U & ~7U;
IndexListEntry *next, *prev;
MachineInstr *mi;
unsigned index;
protected:
typedef enum { EMPTY_KEY, TOMBSTONE_KEY } ReservedEntryType;
// This constructor is only to be used by getEmptyKeyEntry
// & getTombstoneKeyEntry. It sets index to the given
// value and mi to zero.
IndexListEntry(ReservedEntryType r) : mi(0) {
switch(r) {
case EMPTY_KEY: index = EMPTY_KEY_INDEX; break;
case TOMBSTONE_KEY: index = TOMBSTONE_KEY_INDEX; break;
default: assert(false && "Invalid value for constructor.");
}
next = this;
prev = this;
}
public:
IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi), index(index) {
if (index == EMPTY_KEY_INDEX || index == TOMBSTONE_KEY_INDEX) {
llvm_report_error("Attempt to create invalid index. "
"Available indexes may have been exhausted?.");
}
}
MachineInstr* getInstr() const { return mi; }
void setInstr(MachineInstr *mi) {
assert(index != EMPTY_KEY_INDEX && index != TOMBSTONE_KEY_INDEX &&
"Attempt to modify reserved index.");
this->mi = mi;
}
unsigned getIndex() const { return index; }
void setIndex(unsigned index) {
assert(index != EMPTY_KEY_INDEX && index != TOMBSTONE_KEY_INDEX &&
"Attempt to set index to invalid value.");
assert(this->index != EMPTY_KEY_INDEX &&
this->index != TOMBSTONE_KEY_INDEX &&
"Attempt to reset reserved index value.");
this->index = index;
}
IndexListEntry* getNext() { return next; }
const IndexListEntry* getNext() const { return next; }
void setNext(IndexListEntry *next) {
assert(index != EMPTY_KEY_INDEX && index != TOMBSTONE_KEY_INDEX &&
"Attempt to modify reserved index.");
this->next = next;
}
IndexListEntry* getPrev() { return prev; }
const IndexListEntry* getPrev() const { return prev; }
void setPrev(IndexListEntry *prev) {
assert(index != EMPTY_KEY_INDEX && index != TOMBSTONE_KEY_INDEX &&
"Attempt to modify reserved index.");
this->prev = prev;
}
// This function returns the index list entry that is to be used for empty
// SlotIndex keys.
static IndexListEntry* getEmptyKeyEntry();
// This function returns the index list entry that is to be used for
// tombstone SlotIndex keys.
static IndexListEntry* getTombstoneKeyEntry();
};
// 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 struct DenseMapInfo<SlotIndex>;
private:
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 {
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() {
return SlotIndex(IndexListEntry::getEmptyKeyEntry(), 0);
}
static inline SlotIndex getTombstoneKey() {
return SlotIndex(IndexListEntry::getTombstoneKeyEntry(), 0);
}
/// Construct an invalid index.
SlotIndex() : lie(IndexListEntry::getEmptyKeyEntry(), 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.
/// TODO: Not a POD?
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);
}
};
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 renumberIndexes();
/// 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;
}
/// Insert the given machine instruction into the mapping. Returns the
/// assigned index.
SlotIndex insertMachineInstrInMaps(MachineInstr *mi,
bool *deferredRenumber = 0) {
assert(mi2iMap.find(mi) == mi2iMap.end() && "Instr already indexed.");
MachineBasicBlock *mbb = mi->getParent();
assert(mbb != 0 && "Instr must be added to function.");
MBB2IdxMap::iterator mbbRangeItr = mbb2IdxMap.find(mbb);
assert(mbbRangeItr != mbb2IdxMap.end() &&
"Instruction's parent MBB has not been added to SlotIndexes.");
MachineBasicBlock::iterator miItr(mi);
bool needRenumber = false;
IndexListEntry *newEntry;
IndexListEntry *prevEntry;
if (miItr == mbb->begin()) {
// If mi is at the mbb beginning, get the prev index from the mbb.
prevEntry = &mbbRangeItr->second.first.entry();
} else {
// Otherwise get it from the previous instr.
MachineBasicBlock::iterator pItr(prior(miItr));
prevEntry = &getInstructionIndex(pItr).entry();
}
// Get next entry from previous entry.
IndexListEntry *nextEntry = prevEntry->getNext();
// Get a number for the new instr, or 0 if there's no room currently.
// In the latter case we'll force a renumber later.
unsigned dist = nextEntry->getIndex() - prevEntry->getIndex();
unsigned newNumber = dist > SlotIndex::NUM ?
prevEntry->getIndex() + ((dist >> 1) & ~3U) : 0;
if (newNumber == 0) {
needRenumber = true;
}
// Insert a new list entry for mi.
newEntry = createEntry(mi, newNumber);
insert(nextEntry, newEntry);
SlotIndex newIndex(newEntry, SlotIndex::LOAD);
mi2iMap.insert(std::make_pair(mi, newIndex));
if (miItr == mbb->end()) {
// If this is the last instr in the MBB then we need to fix up the bb
// range:
mbbRangeItr->second.second = SlotIndex(newEntry, SlotIndex::STORE);
}
// Renumber if we need to.
if (needRenumber) {
if (deferredRenumber == 0)
renumberIndexes();
else
*deferredRenumber = true;
}
return newIndex;
}
/// Add all instructions in the vector to the index list. This method will
/// defer renumbering until all instrs have been added, and should be
/// preferred when adding multiple instrs.
void insertMachineInstrsInMaps(SmallVectorImpl<MachineInstr*> &mis) {
bool renumber = false;
for (SmallVectorImpl<MachineInstr*>::iterator
miItr = mis.begin(), miEnd = mis.end();
miItr != miEnd; ++miItr) {
insertMachineInstrInMaps(*miItr, &renumber);
}
if (renumber)
renumberIndexes();
}
/// 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
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