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llvm-6502/include/llvm/ADT/DenseMap.h
Benjamin Kramer 42f72e2c16 Sync the __builtin_expects for our 3 quadratically probed hash table implementations. 
This assumes that
  a) finding the bucket containing the value is LIKELY
  b) finding an empty bucket is LIKELY
  c) growing the table is UNLIKELY

I also switched the a) and b) cases for SmallPtrSet as we seem to use
the set mostly more for insertion than for checking existence.

In a simple benchmark consisting of 2^21 insertions of 2^20 unique
pointers into a DenseMap or SmallPtrSet a few percent speedup on average,
but nothing statistically significant.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230232 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-23 16:41:36 +00:00

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//===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the DenseMap class.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ADT_DENSEMAP_H
#define LLVM_ADT_DENSEMAP_H
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/PointerLikeTypeTraits.h"
#include "llvm/Support/type_traits.h"
#include <algorithm>
#include <cassert>
#include <climits>
#include <cstddef>
#include <cstring>
#include <iterator>
#include <new>
#include <utility>
namespace llvm {
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,
typename BucketT>
class DenseMapBase {
public:
typedef unsigned size_type;
typedef KeyT key_type;
typedef ValueT mapped_type;
typedef BucketT value_type;
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());
}
inline iterator end() {
return iterator(getBucketsEnd(), getBucketsEnd(), true);
}
inline const_iterator begin() const {
return empty() ? end() : const_iterator(getBuckets(), getBucketsEnd());
}
inline const_iterator end() const {
return const_iterator(getBucketsEnd(), getBucketsEnd(), true);
}
bool LLVM_ATTRIBUTE_UNUSED_RESULT empty() const {
return getNumEntries() == 0;
}
unsigned size() const { return getNumEntries(); }
/// Grow the densemap so that it has at least Size buckets. Does not shrink
void resize(size_type Size) {
if (Size > getNumBuckets())
grow(Size);
}
void clear() {
if (getNumEntries() == 0 && getNumTombstones() == 0) return;
// If the capacity of the array is huge, and the # elements used is small,
// shrink the array.
if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
shrink_and_clear();
return;
}
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
P->getSecond().~ValueT();
decrementNumEntries();
}
P->getFirst() = EmptyKey;
}
}
assert(getNumEntries() == 0 && "Node count imbalance!");
setNumTombstones(0);
}
/// Return 1 if the specified key is in the map, 0 otherwise.
size_type count(const KeyT &Val) const {
const BucketT *TheBucket;
return LookupBucketFor(Val, TheBucket) ? 1 : 0;
}
iterator find(const KeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return iterator(TheBucket, getBucketsEnd(), true);
return end();
}
const_iterator find(const KeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return const_iterator(TheBucket, getBucketsEnd(), true);
return end();
}
/// Alternate version of find() which allows a different, and possibly
/// less expensive, key type.
/// The DenseMapInfo is responsible for supplying methods
/// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
/// type used.
template<class LookupKeyT>
iterator find_as(const LookupKeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return iterator(TheBucket, getBucketsEnd(), true);
return end();
}
template<class LookupKeyT>
const_iterator find_as(const LookupKeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return const_iterator(TheBucket, getBucketsEnd(), true);
return end();
}
/// lookup - Return the entry for the specified key, or a default
/// constructed value if no such entry exists.
ValueT lookup(const KeyT &Val) const {
const BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return TheBucket->getSecond();
return ValueT();
}
// Inserts key,value pair into the map if the key isn't already in the map.
// If the key is already in the map, it returns false and doesn't update the
// value.
std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
BucketT *TheBucket;
if (LookupBucketFor(KV.first, TheBucket))
return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
false); // Already in map.
// Otherwise, insert the new element.
TheBucket = InsertIntoBucket(KV.first, KV.second, TheBucket);
return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
}
// Inserts key,value pair into the map if the key isn't already in the map.
// If the key is already in the map, it returns false and doesn't update the
// value.
std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
BucketT *TheBucket;
if (LookupBucketFor(KV.first, TheBucket))
return std::make_pair(iterator(TheBucket, getBucketsEnd(), true),
false); // Already in map.
// Otherwise, insert the new element.
TheBucket = InsertIntoBucket(std::move(KV.first),
std::move(KV.second),
TheBucket);
return std::make_pair(iterator(TheBucket, getBucketsEnd(), true), true);
}
/// insert - Range insertion of pairs.
template<typename InputIt>
void insert(InputIt I, InputIt E) {
for (; I != E; ++I)
insert(*I);
}
bool erase(const KeyT &Val) {
BucketT *TheBucket;
if (!LookupBucketFor(Val, TheBucket))
return false; // not in map.
TheBucket->getSecond().~ValueT();
TheBucket->getFirst() = getTombstoneKey();
decrementNumEntries();
incrementNumTombstones();
return true;
}
void erase(iterator I) {
BucketT *TheBucket = &*I;
TheBucket->getSecond().~ValueT();
TheBucket->getFirst() = getTombstoneKey();
decrementNumEntries();
incrementNumTombstones();
}
value_type& FindAndConstruct(const KeyT &Key) {
BucketT *TheBucket;
if (LookupBucketFor(Key, TheBucket))
return *TheBucket;
return *InsertIntoBucket(Key, ValueT(), TheBucket);
}
ValueT &operator[](const KeyT &Key) {
return FindAndConstruct(Key).second;
}
value_type& FindAndConstruct(KeyT &&Key) {
BucketT *TheBucket;
if (LookupBucketFor(Key, TheBucket))
return *TheBucket;
return *InsertIntoBucket(std::move(Key), ValueT(), TheBucket);
}
ValueT &operator[](KeyT &&Key) {
return FindAndConstruct(std::move(Key)).second;
}
/// isPointerIntoBucketsArray - Return true if the specified pointer points
/// somewhere into the DenseMap's array of buckets (i.e. either to a key or
/// value in the DenseMap).
bool isPointerIntoBucketsArray(const void *Ptr) const {
return Ptr >= getBuckets() && Ptr < getBucketsEnd();
}
/// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
/// array. In conjunction with the previous method, this can be used to
/// determine whether an insertion caused the DenseMap to reallocate.
const void *getPointerIntoBucketsArray() const { return getBuckets(); }
protected:
DenseMapBase() {}
void destroyAll() {
if (getNumBuckets() == 0) // Nothing to do.
return;
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
P->getSecond().~ValueT();
P->getFirst().~KeyT();
}
#ifndef NDEBUG
memset((void*)getBuckets(), 0x5a, sizeof(BucketT)*getNumBuckets());
#endif
}
void initEmpty() {
setNumEntries(0);
setNumTombstones(0);
assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&
"# initial buckets must be a power of two!");
const KeyT EmptyKey = getEmptyKey();
for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
new (&B->getFirst()) KeyT(EmptyKey);
}
void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
initEmpty();
// Insert all the old elements.
const KeyT EmptyKey = getEmptyKey();
const KeyT TombstoneKey = getTombstoneKey();
for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
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->getFirst(), DestBucket);
(void)FoundVal; // silence warning.
assert(!FoundVal && "Key already in new map?");
DestBucket->getFirst() = std::move(B->getFirst());
new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
incrementNumEntries();
// Free the value.
B->getSecond().~ValueT();
}
B->getFirst().~KeyT();
}
#ifndef NDEBUG
if (OldBucketsBegin != OldBucketsEnd)
memset((void*)OldBucketsBegin, 0x5a,
sizeof(BucketT) * (OldBucketsEnd - OldBucketsBegin));
#endif
}
template <typename OtherBaseT>
void copyFrom(
const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
assert(&other != this);
assert(getNumBuckets() == other.getNumBuckets());
setNumEntries(other.getNumEntries());
setNumTombstones(other.getNumTombstones());
if (isPodLike<KeyT>::value && isPodLike<ValueT>::value)
memcpy(getBuckets(), other.getBuckets(),
getNumBuckets() * sizeof(BucketT));
else
for (size_t i = 0; i < getNumBuckets(); ++i) {
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());
}
}
void swap(DenseMapBase& RHS) {
std::swap(getNumEntries(), RHS.getNumEntries());
std::swap(getNumTombstones(), RHS.getNumTombstones());
}
static unsigned getHashValue(const KeyT &Val) {
return KeyInfoT::getHashValue(Val);
}
template<typename LookupKeyT>
static unsigned getHashValue(const LookupKeyT &Val) {
return KeyInfoT::getHashValue(Val);
}
static const KeyT getEmptyKey() {
return KeyInfoT::getEmptyKey();
}
static const KeyT getTombstoneKey() {
return KeyInfoT::getTombstoneKey();
}
private:
unsigned getNumEntries() const {
return static_cast<const DerivedT *>(this)->getNumEntries();
}
void setNumEntries(unsigned Num) {
static_cast<DerivedT *>(this)->setNumEntries(Num);
}
void incrementNumEntries() {
setNumEntries(getNumEntries() + 1);
}
void decrementNumEntries() {
setNumEntries(getNumEntries() - 1);
}
unsigned getNumTombstones() const {
return static_cast<const DerivedT *>(this)->getNumTombstones();
}
void setNumTombstones(unsigned Num) {
static_cast<DerivedT *>(this)->setNumTombstones(Num);
}
void incrementNumTombstones() {
setNumTombstones(getNumTombstones() + 1);
}
void decrementNumTombstones() {
setNumTombstones(getNumTombstones() - 1);
}
const BucketT *getBuckets() const {
return static_cast<const DerivedT *>(this)->getBuckets();
}
BucketT *getBuckets() {
return static_cast<DerivedT *>(this)->getBuckets();
}
unsigned getNumBuckets() const {
return static_cast<const DerivedT *>(this)->getNumBuckets();
}
BucketT *getBucketsEnd() {
return getBuckets() + getNumBuckets();
}
const BucketT *getBucketsEnd() const {
return getBuckets() + getNumBuckets();
}
void grow(unsigned AtLeast) {
static_cast<DerivedT *>(this)->grow(AtLeast);
}
void shrink_and_clear() {
static_cast<DerivedT *>(this)->shrink_and_clear();
}
BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
BucketT *TheBucket) {
TheBucket = InsertIntoBucketImpl(Key, TheBucket);
TheBucket->getFirst() = Key;
new (&TheBucket->getSecond()) ValueT(Value);
return TheBucket;
}
BucketT *InsertIntoBucket(const KeyT &Key, ValueT &&Value,
BucketT *TheBucket) {
TheBucket = InsertIntoBucketImpl(Key, TheBucket);
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->getFirst() = std::move(Key);
new (&TheBucket->getSecond()) ValueT(std::move(Value));
return TheBucket;
}
BucketT *InsertIntoBucketImpl(const KeyT &Key, BucketT *TheBucket) {
// If the load of the hash table is more than 3/4, or if fewer than 1/8 of
// the buckets are empty (meaning that many are filled with tombstones),
// grow the table.
//
// The later case is tricky. For example, if we had one empty bucket with
// tons of tombstones, failing lookups (e.g. for insertion) would have to
// probe almost the entire table until it found the empty bucket. If the
// table completely filled with tombstones, no lookup would ever succeed,
// causing infinite loops in lookup.
unsigned NewNumEntries = getNumEntries() + 1;
unsigned NumBuckets = getNumBuckets();
if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)) {
this->grow(NumBuckets * 2);
LookupBucketFor(Key, TheBucket);
NumBuckets = getNumBuckets();
} else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=
NumBuckets/8)) {
this->grow(NumBuckets);
LookupBucketFor(Key, TheBucket);
}
assert(TheBucket);
// Only update the state after we've grown our bucket space appropriately
// so that when growing buckets we have self-consistent entry count.
incrementNumEntries();
// If we are writing over a tombstone, remember this.
const KeyT EmptyKey = getEmptyKey();
if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
decrementNumTombstones();
return TheBucket;
}
/// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
/// FoundBucket. If the bucket contains the key and a value, this returns
/// true, otherwise it returns a bucket with an empty marker or tombstone and
/// returns false.
template<typename LookupKeyT>
bool LookupBucketFor(const LookupKeyT &Val,
const BucketT *&FoundBucket) const {
const BucketT *BucketsPtr = getBuckets();
const unsigned NumBuckets = getNumBuckets();
if (NumBuckets == 0) {
FoundBucket = nullptr;
return false;
}
// FoundTombstone - Keep track of whether we find a tombstone while probing.
const BucketT *FoundTombstone = nullptr;
const KeyT EmptyKey = getEmptyKey();
const KeyT TombstoneKey = getTombstoneKey();
assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
!KeyInfoT::isEqual(Val, TombstoneKey) &&
"Empty/Tombstone value shouldn't be inserted into map!");
unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
unsigned ProbeAmt = 1;
while (1) {
const BucketT *ThisBucket = BucketsPtr + BucketNo;
// Found Val's bucket? If so, return it.
if (LLVM_LIKELY(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 (LLVM_LIKELY(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;
return false;
}
// 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->getFirst(), TombstoneKey) &&
!FoundTombstone)
FoundTombstone = ThisBucket; // Remember the first tombstone found.
// Otherwise, it's a hash collision or a tombstone, continue quadratic
// probing.
BucketNo += ProbeAmt++;
BucketNo &= (NumBuckets-1);
}
}
template <typename LookupKeyT>
bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
const BucketT *ConstFoundBucket;
bool Result = const_cast<const DenseMapBase *>(this)
->LookupBucketFor(Val, ConstFoundBucket);
FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
return Result;
}
public:
/// Return the approximate size (in bytes) of the actual map.
/// This is just the raw memory used by DenseMap.
/// If entries are pointers to objects, the size of the referenced objects
/// are not included.
size_t getMemorySize() const {
return getNumBuckets() * sizeof(BucketT);
}
};
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, BucketT> BaseT;
friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
BucketT *Buckets;
unsigned NumEntries;
unsigned NumTombstones;
unsigned NumBuckets;
public:
explicit DenseMap(unsigned NumInitBuckets = 0) {
init(NumInitBuckets);
}
DenseMap(const DenseMap &other) : BaseT() {
init(0);
copyFrom(other);
}
DenseMap(DenseMap &&other) : BaseT() {
init(0);
swap(other);
}
template<typename InputIt>
DenseMap(const InputIt &I, const InputIt &E) {
init(NextPowerOf2(std::distance(I, E)));
this->insert(I, E);
}
~DenseMap() {
this->destroyAll();
operator delete(Buckets);
}
void swap(DenseMap& RHS) {
std::swap(Buckets, RHS.Buckets);
std::swap(NumEntries, RHS.NumEntries);
std::swap(NumTombstones, RHS.NumTombstones);
std::swap(NumBuckets, RHS.NumBuckets);
}
DenseMap& operator=(const DenseMap& other) {
if (&other != this)
copyFrom(other);
return *this;
}
DenseMap& operator=(DenseMap &&other) {
this->destroyAll();
operator delete(Buckets);
init(0);
swap(other);
return *this;
}
void copyFrom(const DenseMap& other) {
this->destroyAll();
operator delete(Buckets);
if (allocateBuckets(other.NumBuckets)) {
this->BaseT::copyFrom(other);
} else {
NumEntries = 0;
NumTombstones = 0;
}
}
void init(unsigned InitBuckets) {
if (allocateBuckets(InitBuckets)) {
this->BaseT::initEmpty();
} else {
NumEntries = 0;
NumTombstones = 0;
}
}
void grow(unsigned AtLeast) {
unsigned OldNumBuckets = NumBuckets;
BucketT *OldBuckets = Buckets;
allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
assert(Buckets);
if (!OldBuckets) {
this->BaseT::initEmpty();
return;
}
this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
// Free the old table.
operator delete(OldBuckets);
}
void shrink_and_clear() {
unsigned OldNumEntries = NumEntries;
this->destroyAll();
// Reduce the number of buckets.
unsigned NewNumBuckets = 0;
if (OldNumEntries)
NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
if (NewNumBuckets == NumBuckets) {
this->BaseT::initEmpty();
return;
}
operator delete(Buckets);
init(NewNumBuckets);
}
private:
unsigned getNumEntries() const {
return NumEntries;
}
void setNumEntries(unsigned Num) {
NumEntries = Num;
}
unsigned getNumTombstones() const {
return NumTombstones;
}
void setNumTombstones(unsigned Num) {
NumTombstones = Num;
}
BucketT *getBuckets() const {
return Buckets;
}
unsigned getNumBuckets() const {
return NumBuckets;
}
bool allocateBuckets(unsigned Num) {
NumBuckets = Num;
if (NumBuckets == 0) {
Buckets = nullptr;
return false;
}
Buckets = static_cast<BucketT*>(operator new(sizeof(BucketT) * NumBuckets));
return true;
}
};
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, 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, BucketT> BaseT;
friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
unsigned Small : 1;
unsigned NumEntries : 31;
unsigned NumTombstones;
struct LargeRep {
BucketT *Buckets;
unsigned NumBuckets;
};
/// A "union" of an inline bucket array and the struct representing
/// a large bucket. This union will be discriminated by the 'Small' bit.
AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
public:
explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
init(NumInitBuckets);
}
SmallDenseMap(const SmallDenseMap &other) : BaseT() {
init(0);
copyFrom(other);
}
SmallDenseMap(SmallDenseMap &&other) : BaseT() {
init(0);
swap(other);
}
template<typename InputIt>
SmallDenseMap(const InputIt &I, const InputIt &E) {
init(NextPowerOf2(std::distance(I, E)));
this->insert(I, E);
}
~SmallDenseMap() {
this->destroyAll();
deallocateBuckets();
}
void swap(SmallDenseMap& RHS) {
unsigned TmpNumEntries = RHS.NumEntries;
RHS.NumEntries = NumEntries;
NumEntries = TmpNumEntries;
std::swap(NumTombstones, RHS.NumTombstones);
const KeyT EmptyKey = this->getEmptyKey();
const KeyT TombstoneKey = this->getTombstoneKey();
if (Small && RHS.Small) {
// If we're swapping inline bucket arrays, we have to cope with some of
// the tricky bits of DenseMap's storage system: the buckets are not
// fully initialized. Thus we swap every key, but we may have
// a one-directional move of the value.
for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
BucketT *LHSB = &getInlineBuckets()[i],
*RHSB = &RHS.getInlineBuckets()[i];
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->getFirst(), RHSB->getFirst());
if (hasLHSValue) {
new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
LHSB->getSecond().~ValueT();
} else if (hasRHSValue) {
new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
RHSB->getSecond().~ValueT();
}
}
return;
}
if (!Small && !RHS.Small) {
std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
return;
}
SmallDenseMap &SmallSide = Small ? *this : RHS;
SmallDenseMap &LargeSide = Small ? RHS : *this;
// First stash the large side's rep and move the small side across.
LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
LargeSide.getLargeRep()->~LargeRep();
LargeSide.Small = true;
// This is similar to the standard move-from-old-buckets, but the bucket
// count hasn't actually rotated in this case. So we have to carefully
// move construct the keys and values into their new locations, but there
// is no need to re-hash things.
for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
BucketT *NewB = &LargeSide.getInlineBuckets()[i],
*OldB = &SmallSide.getInlineBuckets()[i];
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();
}
}
// The hard part of moving the small buckets across is done, just move
// the TmpRep into its new home.
SmallSide.Small = false;
new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
}
SmallDenseMap& operator=(const SmallDenseMap& other) {
if (&other != this)
copyFrom(other);
return *this;
}
SmallDenseMap& operator=(SmallDenseMap &&other) {
this->destroyAll();
deallocateBuckets();
init(0);
swap(other);
return *this;
}
void copyFrom(const SmallDenseMap& other) {
this->destroyAll();
deallocateBuckets();
Small = true;
if (other.getNumBuckets() > InlineBuckets) {
Small = false;
new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
}
this->BaseT::copyFrom(other);
}
void init(unsigned InitBuckets) {
Small = true;
if (InitBuckets > InlineBuckets) {
Small = false;
new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
}
this->BaseT::initEmpty();
}
void grow(unsigned AtLeast) {
if (AtLeast >= InlineBuckets)
AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
if (Small) {
if (AtLeast < InlineBuckets)
return; // Nothing to do.
// First move the inline buckets into a temporary storage.
AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
BucketT *TmpBegin = reinterpret_cast<BucketT *>(TmpStorage.buffer);
BucketT *TmpEnd = TmpBegin;
// Loop over the buckets, moving non-empty, non-tombstones into the
// temporary storage. Have the loop move the TmpEnd forward as it goes.
const KeyT EmptyKey = this->getEmptyKey();
const KeyT TombstoneKey = this->getTombstoneKey();
for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&
"Too many inline buckets!");
new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
++TmpEnd;
P->getSecond().~ValueT();
}
P->getFirst().~KeyT();
}
// Now make this map use the large rep, and move all the entries back
// into it.
Small = false;
new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
this->moveFromOldBuckets(TmpBegin, TmpEnd);
return;
}
LargeRep OldRep = std::move(*getLargeRep());
getLargeRep()->~LargeRep();
if (AtLeast <= InlineBuckets) {
Small = true;
} else {
new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
}
this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
// Free the old table.
operator delete(OldRep.Buckets);
}
void shrink_and_clear() {
unsigned OldSize = this->size();
this->destroyAll();
// Reduce the number of buckets.
unsigned NewNumBuckets = 0;
if (OldSize) {
NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
NewNumBuckets = 64;
}
if ((Small && NewNumBuckets <= InlineBuckets) ||
(!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
this->BaseT::initEmpty();
return;
}
deallocateBuckets();
init(NewNumBuckets);
}
private:
unsigned getNumEntries() const {
return NumEntries;
}
void setNumEntries(unsigned Num) {
assert(Num < INT_MAX && "Cannot support more than INT_MAX entries");
NumEntries = Num;
}
unsigned getNumTombstones() const {
return NumTombstones;
}
void setNumTombstones(unsigned Num) {
NumTombstones = Num;
}
const BucketT *getInlineBuckets() const {
assert(Small);
// Note that this cast does not violate aliasing rules as we assert that
// the memory's dynamic type is the small, inline bucket buffer, and the
// 'storage.buffer' static type is 'char *'.
return reinterpret_cast<const BucketT *>(storage.buffer);
}
BucketT *getInlineBuckets() {
return const_cast<BucketT *>(
const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
}
const LargeRep *getLargeRep() const {
assert(!Small);
// Note, same rule about aliasing as with getInlineBuckets.
return reinterpret_cast<const LargeRep *>(storage.buffer);
}
LargeRep *getLargeRep() {
return const_cast<LargeRep *>(
const_cast<const SmallDenseMap *>(this)->getLargeRep());
}
const BucketT *getBuckets() const {
return Small ? getInlineBuckets() : getLargeRep()->Buckets;
}
BucketT *getBuckets() {
return const_cast<BucketT *>(
const_cast<const SmallDenseMap *>(this)->getBuckets());
}
unsigned getNumBuckets() const {
return Small ? InlineBuckets : getLargeRep()->NumBuckets;
}
void deallocateBuckets() {
if (Small)
return;
operator delete(getLargeRep()->Buckets);
getLargeRep()->~LargeRep();
}
LargeRep allocateBuckets(unsigned Num) {
assert(Num > InlineBuckets && "Must allocate more buckets than are inline");
LargeRep Rep = {
static_cast<BucketT*>(operator new(sizeof(BucketT) * Num)), Num
};
return Rep;
}
};
template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
bool IsConst>
class DenseMapIterator {
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
value_type;
typedef value_type *pointer;
typedef value_type &reference;
typedef std::forward_iterator_tag iterator_category;
private:
pointer Ptr, End;
public:
DenseMapIterator() : Ptr(nullptr), End(nullptr) {}
DenseMapIterator(pointer Pos, pointer E, bool NoAdvance = false)
: Ptr(Pos), End(E) {
if (!NoAdvance) AdvancePastEmptyBuckets();
}
// 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, Bucket, false> &I)
: Ptr(I.Ptr), End(I.End) {}
reference operator*() const {
return *Ptr;
}
pointer operator->() const {
return Ptr;
}
bool operator==(const ConstIterator &RHS) const {
return Ptr == RHS.operator->();
}
bool operator!=(const ConstIterator &RHS) const {
return Ptr != RHS.operator->();
}
inline DenseMapIterator& operator++() { // Preincrement
++Ptr;
AdvancePastEmptyBuckets();
return *this;
}
DenseMapIterator operator++(int) { // Postincrement
DenseMapIterator tmp = *this; ++*this; return tmp;
}
private:
void AdvancePastEmptyBuckets() {
const KeyT Empty = KeyInfoT::getEmptyKey();
const KeyT Tombstone = KeyInfoT::getTombstoneKey();
while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
++Ptr;
}
};
template<typename KeyT, typename ValueT, typename KeyInfoT>
static inline size_t
capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
return X.getMemorySize();
}
} // end namespace llvm
#endif
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