//
// The LLVM Compiler Infrastructure
//
-// This file was developed by Chris Lattner and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#define LLVM_ADT_DENSEMAP_H
#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/MathExtras.h"
#include <cassert>
#include <utility>
namespace llvm {
template<typename T>
-struct DenseMapKeyInfo {
+struct DenseMapInfo {
//static inline T getEmptyKey();
//static inline T getTombstoneKey();
//static unsigned getHashValue(const T &Val);
+ //static bool isEqual(const T &LHS, const T &RHS);
//static bool isPod()
};
+// Provide DenseMapInfo for all pointers.
template<typename T>
-struct DenseMapKeyInfo<T*> {
- static inline T* getEmptyKey() { return (T*)-1; }
- static inline T* getTombstoneKey() { return (T*)-2; }
+struct DenseMapInfo<T*> {
+ static inline T* getEmptyKey() { return reinterpret_cast<T*>(-1); }
+ static inline T* getTombstoneKey() { return reinterpret_cast<T*>(-2); }
static unsigned getHashValue(const T *PtrVal) {
- return (unsigned)((uintptr_t)PtrVal >> 4) ^
- (unsigned)((uintptr_t)PtrVal >> 9);
+ return (unsigned((uintptr_t)PtrVal) >> 4) ^
+ (unsigned((uintptr_t)PtrVal) >> 9);
}
+ static bool isEqual(const T *LHS, const T *RHS) { return LHS == RHS; }
static bool isPod() { return true; }
};
-template<typename KeyT, typename ValueT>
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapInfo<KeyT>,
+ typename ValueInfoT = DenseMapInfo<ValueT> >
class DenseMapIterator;
-template<typename KeyT, typename ValueT>
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapInfo<KeyT>,
+ typename ValueInfoT = DenseMapInfo<ValueT> >
class DenseMapConstIterator;
-template<typename KeyT, typename ValueT>
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapInfo<KeyT>,
+ typename ValueInfoT = DenseMapInfo<ValueT> >
class DenseMap {
typedef std::pair<KeyT, ValueT> BucketT;
unsigned NumBuckets;
BucketT *Buckets;
unsigned NumEntries;
- DenseMap(const DenseMap &); // not implemented.
+ unsigned NumTombstones;
public:
+ typedef BucketT value_type;
+
+ DenseMap(const DenseMap& other) {
+ NumBuckets = 0;
+ CopyFrom(other);
+ }
+
explicit DenseMap(unsigned NumInitBuckets = 64) {
init(NumInitBuckets);
}
+
~DenseMap() {
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
- if (P->first != EmptyKey && P->first != TombstoneKey)
+ if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
+ !KeyInfoT::isEqual(P->first, TombstoneKey))
P->second.~ValueT();
P->first.~KeyT();
}
- delete[] (char*)Buckets;
+ delete[] reinterpret_cast<char*>(Buckets);
}
- typedef DenseMapIterator<KeyT, ValueT> iterator;
- typedef DenseMapConstIterator<KeyT, ValueT> const_iterator;
+ typedef DenseMapIterator<KeyT, ValueT, KeyInfoT> iterator;
+ typedef DenseMapConstIterator<KeyT, ValueT, KeyInfoT> const_iterator;
inline iterator begin() {
- return DenseMapIterator<KeyT, ValueT>(Buckets, Buckets+NumBuckets);
+ return iterator(Buckets, Buckets+NumBuckets);
}
inline iterator end() {
- return DenseMapIterator<KeyT, ValueT>(Buckets+NumBuckets,
- Buckets+NumBuckets);
+ return iterator(Buckets+NumBuckets, Buckets+NumBuckets);
}
inline const_iterator begin() const {
- return DenseMapConstIterator<KeyT, ValueT>(Buckets, Buckets+NumBuckets);
+ return const_iterator(Buckets, Buckets+NumBuckets);
}
inline const_iterator end() const {
- return DenseMapConstIterator<KeyT, ValueT>(Buckets+NumBuckets,
- Buckets+NumBuckets);
+ return const_iterator(Buckets+NumBuckets, Buckets+NumBuckets);
}
bool empty() const { return NumEntries == 0; }
unsigned size() const { return NumEntries; }
+
+ /// Grow the densemap so that it has at least Size buckets. Does not shrink
+ void resize(size_t Size) { grow(Size); }
void clear() {
+ // If the capacity of the array is huge, and the # elements used is small,
+ // shrink the array.
+ if (NumEntries * 4 < NumBuckets && NumBuckets > 64) {
+ shrink_and_clear();
+ return;
+ }
+
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
- if (P->first != EmptyKey && P->first != TombstoneKey) {
+ if (!KeyInfoT::isEqual(P->first, EmptyKey)) {
+ if (!KeyInfoT::isEqual(P->first, TombstoneKey)) {
+ P->second.~ValueT();
+ --NumEntries;
+ }
P->first = EmptyKey;
- P->second.~ValueT();
- --NumEntries;
}
}
assert(NumEntries == 0 && "Node count imbalance!");
+ NumTombstones = 0;
}
-
+
/// count - Return true if the specified key is in the map.
bool count(const KeyT &Val) const {
BucketT *TheBucket;
return LookupBucketFor(Val, TheBucket);
}
- iterator find(const KeyT &Val) const {
+ iterator find(const KeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
return iterator(TheBucket, Buckets+NumBuckets);
return end();
}
+ const_iterator find(const KeyT &Val) const {
+ BucketT *TheBucket;
+ if (LookupBucketFor(Val, TheBucket))
+ return const_iterator(TheBucket, Buckets+NumBuckets);
+ return end();
+ }
bool insert(const std::pair<KeyT, ValueT> &KV) {
BucketT *TheBucket;
TheBucket->second.~ValueT();
TheBucket->first = getTombstoneKey();
--NumEntries;
+ ++NumTombstones;
return true;
}
bool erase(iterator I) {
TheBucket->second.~ValueT();
TheBucket->first = getTombstoneKey();
--NumEntries;
+ ++NumTombstones;
return true;
}
-
- ValueT &operator[](const KeyT &Key) {
+
+ value_type& FindAndConstruct(const KeyT &Key) {
BucketT *TheBucket;
if (LookupBucketFor(Key, TheBucket))
- return TheBucket->second;
-
- return InsertIntoBucket(Key, ValueT(), TheBucket)->second;
+ return *TheBucket;
+
+ return *InsertIntoBucket(Key, ValueT(), TheBucket);
+ }
+
+ ValueT &operator[](const KeyT &Key) {
+ return FindAndConstruct(Key).second;
+ }
+
+ DenseMap& operator=(const DenseMap& other) {
+ CopyFrom(other);
+ return *this;
}
private:
+ void CopyFrom(const DenseMap& other) {
+ if (NumBuckets != 0 && (!KeyInfoT::isPod() || !ValueInfoT::isPod())) {
+ const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
+ for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
+ if (!KeyInfoT::isEqual(P->first, EmptyKey) &&
+ !KeyInfoT::isEqual(P->first, TombstoneKey))
+ P->second.~ValueT();
+ P->first.~KeyT();
+ }
+ }
+
+ NumEntries = other.NumEntries;
+ NumTombstones = other.NumTombstones;
+
+ if (NumBuckets)
+ delete[] reinterpret_cast<char*>(Buckets);
+ Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT) *
+ other.NumBuckets]);
+
+ if (KeyInfoT::isPod() && ValueInfoT::isPod())
+ memcpy(Buckets, other.Buckets, other.NumBuckets * sizeof(BucketT));
+ else
+ for (size_t i = 0; i < other.NumBuckets; ++i) {
+ new (Buckets[i].first) KeyT(other.Buckets[i].first);
+ if (!KeyInfoT::isEqual(Buckets[i].first, getEmptyKey()) &&
+ !KeyInfoT::isEqual(Buckets[i].first, getTombstoneKey()))
+ new (&Buckets[i].second) ValueT(other.Buckets[i].second);
+ }
+ NumBuckets = other.NumBuckets;
+ }
+
BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
BucketT *TheBucket) {
- // If the load of the hash table is more than 3/4, grow it.
- if (NumEntries*4 >= NumBuckets*3) {
- this->grow();
+ // 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.
+ if (NumEntries*4 >= NumBuckets*3 ||
+ NumBuckets-(NumEntries+NumTombstones) < NumBuckets/8) {
+ this->grow(NumBuckets * 2);
LookupBucketFor(Key, TheBucket);
}
++NumEntries;
+
+ // If we are writing over a tombstone, remember this.
+ if (!KeyInfoT::isEqual(TheBucket->first, getEmptyKey()))
+ --NumTombstones;
+
TheBucket->first = Key;
new (&TheBucket->second) ValueT(Value);
return TheBucket;
}
static unsigned getHashValue(const KeyT &Val) {
- return DenseMapKeyInfo<KeyT>::getHashValue(Val);
+ return KeyInfoT::getHashValue(Val);
}
static const KeyT getEmptyKey() {
- return DenseMapKeyInfo<KeyT>::getEmptyKey();
+ return KeyInfoT::getEmptyKey();
}
static const KeyT getTombstoneKey() {
- return DenseMapKeyInfo<KeyT>::getTombstoneKey();
+ return KeyInfoT::getTombstoneKey();
}
/// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
BucketT *FoundTombstone = 0;
const KeyT EmptyKey = getEmptyKey();
const KeyT TombstoneKey = getTombstoneKey();
- assert(Val != EmptyKey && Val != TombstoneKey &&
+ assert(!KeyInfoT::isEqual(Val, EmptyKey) &&
+ !KeyInfoT::isEqual(Val, TombstoneKey) &&
"Empty/Tombstone value shouldn't be inserted into map!");
while (1) {
BucketT *ThisBucket = BucketsPtr + (BucketNo & (NumBuckets-1));
// Found Val's bucket? If so, return it.
- if (ThisBucket->first == Val) {
+ if (KeyInfoT::isEqual(ThisBucket->first, Val)) {
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 (ThisBucket->first == EmptyKey) {
+ if (KeyInfoT::isEqual(ThisBucket->first, EmptyKey)) {
// If we've already seen a tombstone while probing, fill it in instead
// of the empty bucket we eventually probed to.
if (FoundTombstone) ThisBucket = FoundTombstone;
// 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 (ThisBucket->first == TombstoneKey && !FoundTombstone)
+ if (KeyInfoT::isEqual(ThisBucket->first, TombstoneKey) && !FoundTombstone)
FoundTombstone = ThisBucket; // Remember the first tombstone found.
// Otherwise, it's a hash collision or a tombstone, continue quadratic
void init(unsigned InitBuckets) {
NumEntries = 0;
+ NumTombstones = 0;
NumBuckets = InitBuckets;
assert(InitBuckets && (InitBuckets & InitBuckets-1) == 0 &&
"# initial buckets must be a power of two!");
- Buckets = (BucketT*)new char[sizeof(BucketT)*InitBuckets];
+ Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*InitBuckets]);
// Initialize all the keys to EmptyKey.
const KeyT EmptyKey = getEmptyKey();
for (unsigned i = 0; i != InitBuckets; ++i)
new (&Buckets[i].first) KeyT(EmptyKey);
}
- void grow() {
+ void grow(unsigned AtLeast) {
unsigned OldNumBuckets = NumBuckets;
BucketT *OldBuckets = Buckets;
// Double the number of buckets.
- NumBuckets <<= 1;
- Buckets = (BucketT*)new char[sizeof(BucketT)*NumBuckets];
+ while (NumBuckets <= AtLeast)
+ NumBuckets <<= 1;
+ NumTombstones = 0;
+ Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*NumBuckets]);
// Initialize all the keys to EmptyKey.
const KeyT EmptyKey = getEmptyKey();
// Insert all the old elements.
const KeyT TombstoneKey = getTombstoneKey();
for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
- if (B->first != EmptyKey && B->first != TombstoneKey) {
+ if (!KeyInfoT::isEqual(B->first, EmptyKey) &&
+ !KeyInfoT::isEqual(B->first, TombstoneKey)) {
// Insert the key/value into the new table.
BucketT *DestBucket;
bool FoundVal = LookupBucketFor(B->first, DestBucket);
}
// Free the old table.
- delete[] (char*)OldBuckets;
+ delete[] reinterpret_cast<char*>(OldBuckets);
+ }
+
+ void shrink_and_clear() {
+ unsigned OldNumBuckets = NumBuckets;
+ BucketT *OldBuckets = Buckets;
+
+ // Reduce the number of buckets.
+ NumBuckets = NumEntries > 32 ? 1 << (Log2_32_Ceil(NumEntries) + 1)
+ : 64;
+ NumTombstones = 0;
+ Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*NumBuckets]);
+
+ // Initialize all the keys to EmptyKey.
+ const KeyT EmptyKey = getEmptyKey();
+ for (unsigned i = 0, e = NumBuckets; i != e; ++i)
+ new (&Buckets[i].first) KeyT(EmptyKey);
+
+ // Free the old buckets.
+ const KeyT TombstoneKey = getTombstoneKey();
+ for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
+ if (!KeyInfoT::isEqual(B->first, EmptyKey) &&
+ !KeyInfoT::isEqual(B->first, TombstoneKey)) {
+ // Free the value.
+ B->second.~ValueT();
+ }
+ B->first.~KeyT();
+ }
+
+ // Free the old table.
+ delete[] reinterpret_cast<char*>(OldBuckets);
+
+ NumEntries = 0;
}
};
-template<typename KeyT, typename ValueT>
+template<typename KeyT, typename ValueT, typename KeyInfoT, typename ValueInfoT>
class DenseMapIterator {
typedef std::pair<KeyT, ValueT> BucketT;
protected:
private:
void AdvancePastEmptyBuckets() {
- const KeyT Empty = DenseMapKeyInfo<KeyT>::getEmptyKey();
- const KeyT Tombstone = DenseMapKeyInfo<KeyT>::getTombstoneKey();
+ const KeyT Empty = KeyInfoT::getEmptyKey();
+ const KeyT Tombstone = KeyInfoT::getTombstoneKey();
- while (Ptr != End && (Ptr->first == Empty || Ptr->first == Tombstone))
+ while (Ptr != End &&
+ (KeyInfoT::isEqual(Ptr->first, Empty) ||
+ KeyInfoT::isEqual(Ptr->first, Tombstone)))
++Ptr;
}
};
-template<typename KeyT, typename ValueT>
-class DenseMapConstIterator : public DenseMapIterator<KeyT, ValueT> {
+template<typename KeyT, typename ValueT, typename KeyInfoT, typename ValueInfoT>
+class DenseMapConstIterator : public DenseMapIterator<KeyT, ValueT, KeyInfoT> {
public:
DenseMapConstIterator(const std::pair<KeyT, ValueT> *Pos,
const std::pair<KeyT, ValueT> *E)
- : DenseMapIterator<KeyT, ValueT>(Pos, E) {
+ : DenseMapIterator<KeyT, ValueT, KeyInfoT>(Pos, E) {
}
const std::pair<KeyT, ValueT> &operator*() const {
return *this->Ptr;
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