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Make the DenseMap bucket type configurable and use a smaller bucket for DenseSet. 

DenseSet used to be implemented as DenseMap<Key, char>, which usually doubled
the memory footprint of the map. Now we use a compressed set so the second
element uses no memory at all. This required some surgery on DenseMap as
all accesses to the bucket now have to go through methods; this should
have no impact on the behavior of DenseMap though. The new default bucket
type for DenseMap is a slightly extended std::pair as we expose it through
DenseMap's iterator and don't want to break any existing users.

llvm-svn: 223588
This commit is contained in:
Benjamin Kramer 2014-12-06 19:22:44 +00:00
parent 8e5dc53784
commit 89e5306f43
4 changed files with 133 additions and 108 deletions
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202
llvm/include/llvm/ADT/DenseMap.h
View File

@ -31,26 +31,35 @@
namespace llvm {
template<typename KeyT, typename ValueT,
typename KeyInfoT = DenseMapInfo<KeyT>,
bool IsConst = false>
namespace detail {
// We extend a pair to allow users to override the bucket type with their own
// implementation without requiring two members.
template <typename KeyT, typename ValueT>
struct DenseMapPair : public std::pair<KeyT, ValueT> {
KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
};
}
template <
typename KeyT, typename ValueT, typename KeyInfoT = DenseMapInfo<KeyT>,
typename Bucket = detail::DenseMapPair<KeyT, ValueT>, bool IsConst = false>
class DenseMapIterator;
template<typename DerivedT,
typename KeyT, typename ValueT, typename KeyInfoT>
template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
typename BucketT>
class DenseMapBase {
protected:
typedef std::pair<KeyT, ValueT> BucketT;
public:
typedef unsigned size_type;
typedef KeyT key_type;
typedef ValueT mapped_type;
typedef BucketT value_type;
typedef DenseMapIterator<KeyT, ValueT, KeyInfoT> iterator;
typedef DenseMapIterator<KeyT, ValueT,
KeyInfoT, true> const_iterator;
typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT> iterator;
typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>
const_iterator;
inline iterator begin() {
// When the map is empty, avoid the overhead of AdvancePastEmptyBuckets().
return empty() ? end() : iterator(getBuckets(), getBucketsEnd());
@ -88,12 +97,12 @@ public:
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->first, EmptyKey)) {
if (!KeyInfoT::isEqual(P->first, TombstoneKey)) {
P->second.~ValueT();
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
P->getSecond().~ValueT();
decrementNumEntries();
}
P->first = EmptyKey;
P->getFirst() = EmptyKey;
}
}
assert(getNumEntries() == 0 && "Node count imbalance!");
@ -144,7 +153,7 @@ public:
ValueT lookup(const KeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return TheBucket->second;
return TheBucket->getSecond();
return ValueT();
}
@ -191,16 +200,16 @@ public:
if (!LookupBucketFor(Val, TheBucket))
return false; // not in map.
TheBucket->second.~ValueT();
TheBucket->first = getTombstoneKey();
TheBucket->getSecond().~ValueT();
TheBucket->getFirst() = getTombstoneKey();
decrementNumEntries();
incrementNumTombstones();
return true;
}
void erase(iterator I) {
BucketT *TheBucket = &*I;
TheBucket->second.~ValueT();
TheBucket->first = getTombstoneKey();
TheBucket->getSecond().~ValueT();
TheBucket->getFirst() = getTombstoneKey();
decrementNumEntries();
incrementNumTombstones();
}
@ -250,10 +259,10 @@ protected:
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
!KeyInfoT::isEqual(P->first, TombstoneKey))
P->second.~ValueT();
P->first.~KeyT();
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
P->getSecond().~ValueT();
P->getFirst().~KeyT();
}
#ifndef NDEBUG
@ -269,7 +278,7 @@ protected:
"# initial buckets must be a power of two!");
const KeyT EmptyKey = getEmptyKey();
for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
new (&B->first) KeyT(EmptyKey);
new (&B->getFirst()) KeyT(EmptyKey);
}
void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
@ -279,21 +288,21 @@ protected:
const KeyT EmptyKey = getEmptyKey();
const KeyT TombstoneKey = getTombstoneKey();
for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
if (!KeyInfoT::isEqual(B->first, EmptyKey) &&
!KeyInfoT::isEqual(B->first, TombstoneKey)) {
if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
// Insert the key/value into the new table.
BucketT *DestBucket;
bool FoundVal = LookupBucketFor(B->first, DestBucket);
bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
(void)FoundVal; // silence warning.
assert(!FoundVal && "Key already in new map?");
DestBucket->first = std::move(B->first);
new (&DestBucket->second) ValueT(std::move(B->second));
DestBucket->getFirst() = std::move(B->getFirst());
new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
incrementNumEntries();
// Free the value.
B->second.~ValueT();
B->getSecond().~ValueT();
}
B->first.~KeyT();
B->getFirst().~KeyT();
}
#ifndef NDEBUG
@ -304,7 +313,8 @@ protected:
}
template <typename OtherBaseT>
void copyFrom(const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT>& other) {
void copyFrom(
const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
assert(&other != this);
assert(getNumBuckets() == other.getNumBuckets());
@ -316,10 +326,12 @@ protected:
getNumBuckets() * sizeof(BucketT));
else
for (size_t i = 0; i < getNumBuckets(); ++i) {
new (&getBuckets()[i].first) KeyT(other.getBuckets()[i].first);
if (!KeyInfoT::isEqual(getBuckets()[i].first, getEmptyKey()) &&
!KeyInfoT::isEqual(getBuckets()[i].first, getTombstoneKey()))
new (&getBuckets()[i].second) ValueT(other.getBuckets()[i].second);
new (&getBuckets()[i].getFirst())
KeyT(other.getBuckets()[i].getFirst());
if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
new (&getBuckets()[i].getSecond())
ValueT(other.getBuckets()[i].getSecond());
}
}
@ -396,8 +408,8 @@ private:
BucketT *TheBucket) {
TheBucket = InsertIntoBucketImpl(Key, TheBucket);
TheBucket->first = Key;
new (&TheBucket->second) ValueT(Value);
TheBucket->getFirst() = Key;
new (&TheBucket->getSecond()) ValueT(Value);
return TheBucket;
}
@ -405,16 +417,16 @@ private:
BucketT *TheBucket) {
TheBucket = InsertIntoBucketImpl(Key, TheBucket);
TheBucket->first = Key;
new (&TheBucket->second) ValueT(std::move(Value));
TheBucket->getFirst() = Key;
new (&TheBucket->getSecond()) ValueT(std::move(Value));
return TheBucket;
}
BucketT *InsertIntoBucket(KeyT &&Key, ValueT &&Value, BucketT *TheBucket) {
TheBucket = InsertIntoBucketImpl(Key, TheBucket);
TheBucket->first = std::move(Key);
new (&TheBucket->second) ValueT(std::move(Value));
TheBucket->getFirst() = std::move(Key);
new (&TheBucket->getSecond()) ValueT(std::move(Value));
return TheBucket;
}
@ -446,7 +458,7 @@ private:
// If we are writing over a tombstone, remember this.
const KeyT EmptyKey = getEmptyKey();
if (!KeyInfoT::isEqual(TheBucket->first, EmptyKey))
if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
decrementNumTombstones();
return TheBucket;
@ -480,14 +492,14 @@ private:
while (1) {
const BucketT *ThisBucket = BucketsPtr + BucketNo;
// Found Val's bucket? If so, return it.
if (KeyInfoT::isEqual(Val, ThisBucket->first)) {
if (KeyInfoT::isEqual(Val, ThisBucket->getFirst())) {
FoundBucket = ThisBucket;
return true;
}
// If we found an empty bucket, the key doesn't exist in the set.
// Insert it and return the default value.
if (KeyInfoT::isEqual(ThisBucket->first, EmptyKey)) {
if (KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey)) {
// If we've already seen a tombstone while probing, fill it in instead
// of the empty bucket we eventually probed to.
FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
@ -496,7 +508,8 @@ private:
// If this is a tombstone, remember it. If Val ends up not in the map, we
// prefer to return it than something that would require more probing.
if (KeyInfoT::isEqual(ThisBucket->first, TombstoneKey) && !FoundTombstone)
if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
!FoundTombstone)
FoundTombstone = ThisBucket; // Remember the first tombstone found.
// Otherwise, it's a hash collision or a tombstone, continue quadratic
@ -525,16 +538,15 @@ public:
}
};
template<typename KeyT, typename ValueT,
typename KeyInfoT = DenseMapInfo<KeyT> >
class DenseMap
: public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT>,
KeyT, ValueT, KeyInfoT> {
template <typename KeyT, typename ValueT,
typename KeyInfoT = DenseMapInfo<KeyT>,
typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
KeyT, ValueT, KeyInfoT, BucketT> {
// Lift some types from the dependent base class into this class for
// simplicity of referring to them.
typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT> BaseT;
typedef typename BaseT::BucketT BucketT;
friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT>;
typedef DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
BucketT *Buckets;
unsigned NumEntries;
@ -677,17 +689,17 @@ private:
}
};
template<typename KeyT, typename ValueT,
unsigned InlineBuckets = 4,
typename KeyInfoT = DenseMapInfo<KeyT> >
template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
typename KeyInfoT = DenseMapInfo<KeyT>,
typename BucketT = detail::DenseMapPair<KeyT, ValueT>>
class SmallDenseMap
: public DenseMapBase<SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT>,
KeyT, ValueT, KeyInfoT> {
: public DenseMapBase<
SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
ValueT, KeyInfoT, BucketT> {
// Lift some types from the dependent base class into this class for
// simplicity of referring to them.
typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT> BaseT;
typedef typename BaseT::BucketT BucketT;
friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT>;
typedef DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT> BaseT;
friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
unsigned Small : 1;
unsigned NumEntries : 31;
@ -744,23 +756,23 @@ public:
for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
BucketT *LHSB = &getInlineBuckets()[i],
*RHSB = &RHS.getInlineBuckets()[i];
bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->first, EmptyKey) &&
!KeyInfoT::isEqual(LHSB->first, TombstoneKey));
bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->first, EmptyKey) &&
!KeyInfoT::isEqual(RHSB->first, TombstoneKey));
bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
if (hasLHSValue && hasRHSValue) {
// Swap together if we can...
std::swap(*LHSB, *RHSB);
continue;
}
// Swap separately and handle any assymetry.
std::swap(LHSB->first, RHSB->first);
std::swap(LHSB->getFirst(), RHSB->getFirst());
if (hasLHSValue) {
new (&RHSB->second) ValueT(std::move(LHSB->second));
LHSB->second.~ValueT();
new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
LHSB->getSecond().~ValueT();
} else if (hasRHSValue) {
new (&LHSB->second) ValueT(std::move(RHSB->second));
RHSB->second.~ValueT();
new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
RHSB->getSecond().~ValueT();
}
}
return;
@ -785,12 +797,12 @@ public:
for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
BucketT *NewB = &LargeSide.getInlineBuckets()[i],
*OldB = &SmallSide.getInlineBuckets()[i];
new (&NewB->first) KeyT(std::move(OldB->first));
OldB->first.~KeyT();
if (!KeyInfoT::isEqual(NewB->first, EmptyKey) &&
!KeyInfoT::isEqual(NewB->first, TombstoneKey)) {
new (&NewB->second) ValueT(std::move(OldB->second));
OldB->second.~ValueT();
new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
OldB->getFirst().~KeyT();
if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
OldB->getSecond().~ValueT();
}
}
@ -852,16 +864,16 @@ public:
const KeyT EmptyKey = this->getEmptyKey();
const KeyT TombstoneKey = this->getTombstoneKey();
for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
!KeyInfoT::isEqual(P->first, TombstoneKey)) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
"Too many inline buckets!");
new (&TmpEnd->first) KeyT(std::move(P->first));
new (&TmpEnd->second) ValueT(std::move(P->second));
new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
++TmpEnd;
P->second.~ValueT();
P->getSecond().~ValueT();
}
P->first.~KeyT();
P->getFirst().~KeyT();
}
// Now make this map use the large rep, and move all the entries back
@ -972,13 +984,12 @@ private:
}
};
template<typename KeyT, typename ValueT,
typename KeyInfoT, bool IsConst>
template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
bool IsConst>
class DenseMapIterator {
typedef std::pair<KeyT, ValueT> Bucket;
typedef DenseMapIterator<KeyT, ValueT,
KeyInfoT, true> ConstIterator;
friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, true>;
typedef DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true> ConstIterator;
friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
public:
typedef ptrdiff_t difference_type;
typedef typename std::conditional<IsConst, const Bucket, Bucket>::type
@ -999,9 +1010,9 @@ public:
// If IsConst is true this is a converting constructor from iterator to
// const_iterator and the default copy constructor is used.
// Otherwise this is a copy constructor for iterator.
DenseMapIterator(const DenseMapIterator<KeyT, ValueT,
KeyInfoT, false>& I)
: Ptr(I.Ptr), End(I.End) {}
DenseMapIterator(
const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false> &I)
: Ptr(I.Ptr), End(I.End) {}
reference operator*() const {
return *Ptr;
@ -1031,9 +1042,8 @@ private:
const KeyT Empty = KeyInfoT::getEmptyKey();
const KeyT Tombstone = KeyInfoT::getTombstoneKey();
while (Ptr != End &&
(KeyInfoT::isEqual(Ptr->first, Empty) ||
KeyInfoT::isEqual(Ptr->first, Tombstone)))
while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
++Ptr;
}
};

35
llvm/include/llvm/ADT/DenseSet.h
View File

@ -18,13 +18,29 @@
namespace llvm {
namespace detail {
struct DenseSetEmpty {};
// Use the empty base class trick so we can create a DenseMap where the buckets
// contain only a single item.
template <typename KeyT> class DenseSetPair : public DenseSetEmpty {
KeyT key;
public:
KeyT &getFirst() { return key; }
const KeyT &getFirst() const { return key; }
DenseSetEmpty &getSecond() { return *this; }
const DenseSetEmpty &getSecond() const { return *this; }
};
}
/// DenseSet - This implements a dense probed hash-table based set.
///
/// FIXME: This is currently implemented directly in terms of DenseMap, this
/// should be optimized later if there is a need.
template<typename ValueT, typename ValueInfoT = DenseMapInfo<ValueT> >
class DenseSet {
typedef DenseMap<ValueT, char, ValueInfoT> MapTy;
typedef DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
detail::DenseSetPair<ValueT>> MapTy;
static_assert(sizeof(typename MapTy::value_type) == sizeof(ValueT),
"DenseMap buckets unexpectedly large!");
MapTy TheMap;
public:
typedef ValueT key_type;
@ -72,8 +88,8 @@ public:
Iterator(const typename MapTy::iterator &i) : I(i) {}
ValueT& operator*() { return I->first; }
ValueT* operator->() { return &I->first; }
ValueT &operator*() { return I->getFirst(); }
ValueT *operator->() { return &I->getFirst(); }
Iterator& operator++() { ++I; return *this; }
bool operator==(const Iterator& X) const { return I == X.I; }
@ -92,8 +108,8 @@ public:
ConstIterator(const typename MapTy::const_iterator &i) : I(i) {}
const ValueT& operator*() { return I->first; }
const ValueT* operator->() { return &I->first; }
const ValueT &operator*() { return I->getFirst(); }
const ValueT *operator->() { return &I->getFirst(); }
ConstIterator& operator++() { ++I; return *this; }
bool operator==(const ConstIterator& X) const { return I == X.I; }
@ -129,7 +145,8 @@ public:
void erase(ConstIterator CI) { return TheMap.erase(CI.I); }
std::pair<iterator, bool> insert(const ValueT &V) {
return TheMap.insert(std::make_pair(V, 0));
detail::DenseSetEmpty Empty;
return TheMap.insert(std::make_pair(V, Empty));
}
// Range insertion of values.

2
llvm/include/llvm/IR/Module.h
View File

@ -33,8 +33,6 @@ class GVMaterializer;
class LLVMContext;
class RandomNumberGenerator;
class StructType;
template<typename T> struct DenseMapInfo;
template<typename KeyT, typename ValueT, typename KeyInfoT> class DenseMap;
template<> struct ilist_traits<Function>
: public SymbolTableListTraits<Function, Module> {

2
llvm/lib/Target/AArch64/AArch64PromoteConstant.cpp
View File

@ -193,7 +193,7 @@ private:
// Inserting into the DenseMap may invalidate existing iterator.
// Keep a copy of the key to find the iterator to erase.
Instruction *OldInstr = IPI->first;
InsertPts.insert(InsertionPoints::value_type(NewPt, IPI->second));
InsertPts[NewPt] = std::move(IPI->second);
// Erase IPI.
IPI = InsertPts.find(OldInstr);
InsertPts.erase(IPI);