#include "llvm/Support/DataTypes.h"
#include <cassert>
+#include <utility>
namespace llvm {
//static bool isPod()
};
+// Provide DenseMapKeyInfo for all pointers.
template<typename T>
struct DenseMapKeyInfo<T*> {
static inline T* getEmptyKey() { return (T*)-1; }
static bool isPod() { return true; }
};
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT> >
+class DenseMapIterator;
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT> >
+class DenseMapConstIterator;
-template<typename KeyT, typename ValueT>
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT> >
class DenseMap {
- struct BucketT { KeyT Key; ValueT Value; };
+ typedef std::pair<KeyT, ValueT> BucketT;
unsigned NumBuckets;
BucketT *Buckets;
unsigned NumEntries;
+ unsigned NumTombstones;
DenseMap(const DenseMap &); // not implemented.
public:
- explicit DenseMap(unsigned NumInitBuckets = 8) {
+ 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->Key != EmptyKey && P->Key != TombstoneKey)
- P->Value.~ValueT();
- P->Key.~KeyT();
+ if (P->first != EmptyKey && P->first != TombstoneKey)
+ P->second.~ValueT();
+ P->first.~KeyT();
}
delete[] (char*)Buckets;
}
+ typedef DenseMapIterator<KeyT, ValueT, KeyInfoT> iterator;
+ typedef DenseMapConstIterator<KeyT, ValueT, KeyInfoT> const_iterator;
+ inline iterator begin() {
+ return iterator(Buckets, Buckets+NumBuckets);
+ }
+ inline iterator end() {
+ return iterator(Buckets+NumBuckets, Buckets+NumBuckets);
+ }
+ inline const_iterator begin() const {
+ return const_iterator(Buckets, Buckets+NumBuckets);
+ }
+ inline const_iterator end() const {
+ return const_iterator(Buckets+NumBuckets, Buckets+NumBuckets);
+ }
+
+ bool empty() const { return NumEntries == 0; }
unsigned size() const { return NumEntries; }
void clear() {
const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
for (BucketT *P = Buckets, *E = Buckets+NumBuckets; P != E; ++P) {
- if (P->Key != EmptyKey && P->Key != TombstoneKey) {
- P->Key = EmptyKey;
- P->Value.~ValueT();
+ if (P->first != EmptyKey && P->first != TombstoneKey) {
+ 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.
return LookupBucketFor(Val, TheBucket);
}
- ValueT &operator[](const KeyT &Val) {
+ iterator find(const KeyT &Val) {
BucketT *TheBucket;
if (LookupBucketFor(Val, TheBucket))
- return TheBucket->Value;
+ 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;
+ if (LookupBucketFor(KV.first, TheBucket))
+ return false; // Already in map.
+
+ // Otherwise, insert the new element.
+ InsertIntoBucket(KV.first, KV.second, TheBucket);
+ return true;
+ }
+
+ bool erase(const KeyT &Val) {
+ BucketT *TheBucket;
+ if (!LookupBucketFor(Val, TheBucket))
+ return false; // not in map.
+
+ TheBucket->second.~ValueT();
+ TheBucket->first = getTombstoneKey();
+ --NumEntries;
+ ++NumTombstones;
+ return true;
+ }
+ bool erase(iterator I) {
+ BucketT *TheBucket = &*I;
+ TheBucket->second.~ValueT();
+ TheBucket->first = getTombstoneKey();
+ --NumEntries;
+ ++NumTombstones;
+ return true;
+ }
+
+ ValueT &operator[](const KeyT &Key) {
+ BucketT *TheBucket;
+ if (LookupBucketFor(Key, TheBucket))
+ return TheBucket->second;
- // If the load of the hash table is more than 3/4, grow it.
- if (NumEntries*4 >= NumBuckets*3) {
+ return InsertIntoBucket(Key, ValueT(), TheBucket)->second;
+ }
+
+private:
+ BucketT *InsertIntoBucket(const KeyT &Key, const ValueT &Value,
+ 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.
+ if (NumEntries*4 >= NumBuckets*3 ||
+ NumBuckets-(NumEntries+NumTombstones) < NumBuckets/8) {
this->grow();
- LookupBucketFor(Val, TheBucket);
+ LookupBucketFor(Key, TheBucket);
}
++NumEntries;
- TheBucket->Key = Val;
- new (&TheBucket->Value) ValueT();
- return TheBucket->Value;
+
+ // If we are writing over a tombstone, remember this.
+ if (TheBucket->first != getEmptyKey())
+ --NumTombstones;
+
+ TheBucket->first = Key;
+ new (&TheBucket->second) ValueT(Value);
+ return TheBucket;
}
-
-private:
- unsigned getHashValue(const KeyT &Val) const {
- return DenseMapKeyInfo<KeyT>::getHashValue(Val);
+
+ static unsigned getHashValue(const KeyT &Val) {
+ return KeyInfoT::getHashValue(Val);
}
- const KeyT getEmptyKey() const { return DenseMapKeyInfo<KeyT>::getEmptyKey();}
- const KeyT getTombstoneKey() const {
- return DenseMapKeyInfo<KeyT>::getTombstoneKey();
+ static const KeyT getEmptyKey() {
+ return KeyInfoT::getEmptyKey();
+ }
+ static const KeyT getTombstoneKey() {
+ return KeyInfoT::getTombstoneKey();
}
/// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
while (1) {
BucketT *ThisBucket = BucketsPtr + (BucketNo & (NumBuckets-1));
// Found Val's bucket? If so, return it.
- if (ThisBucket->Key == Val) {
+ if (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->Key == EmptyKey) {
+ if (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->Key == TombstoneKey && !FoundTombstone)
+ if (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!");
// Initialize all the keys to EmptyKey.
const KeyT EmptyKey = getEmptyKey();
for (unsigned i = 0; i != InitBuckets; ++i)
- new (&Buckets[i].Key) KeyT(EmptyKey);
+ new (&Buckets[i].first) KeyT(EmptyKey);
}
void grow() {
// Double the number of buckets.
NumBuckets <<= 1;
+ NumTombstones = 0;
Buckets = (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].Key) KeyT(EmptyKey);
+ new (&Buckets[i].first) KeyT(EmptyKey);
// Insert all the old elements.
const KeyT TombstoneKey = getTombstoneKey();
for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
- if (B->Key != EmptyKey && B->Key != TombstoneKey) {
+ if (B->first != EmptyKey && B->first != TombstoneKey) {
// Insert the key/value into the new table.
BucketT *DestBucket;
- bool FoundVal = LookupBucketFor(B->Key, DestBucket);
+ bool FoundVal = LookupBucketFor(B->first, DestBucket);
+ FoundVal = FoundVal; // silence warning.
assert(!FoundVal && "Key already in new map?");
- DestBucket->Key = B->Key;
- new (&DestBucket->Value) ValueT(B->Value);
+ DestBucket->first = B->first;
+ new (&DestBucket->second) ValueT(B->second);
// Free the value.
- B->Value.~ValueT();
+ B->second.~ValueT();
}
- B->Key.~KeyT();
+ B->first.~KeyT();
}
// Free the old table.
}
};
+template<typename KeyT, typename ValueT, typename KeyInfoT>
+class DenseMapIterator {
+ typedef std::pair<KeyT, ValueT> BucketT;
+protected:
+ const BucketT *Ptr, *End;
+public:
+ DenseMapIterator(const BucketT *Pos, const BucketT *E) : Ptr(Pos), End(E) {
+ AdvancePastEmptyBuckets();
+ }
+
+ std::pair<KeyT, ValueT> &operator*() const {
+ return *const_cast<BucketT*>(Ptr);
+ }
+ std::pair<KeyT, ValueT> *operator->() const {
+ return const_cast<BucketT*>(Ptr);
+ }
+
+ bool operator==(const DenseMapIterator &RHS) const {
+ return Ptr == RHS.Ptr;
+ }
+ bool operator!=(const DenseMapIterator &RHS) const {
+ return Ptr != RHS.Ptr;
+ }
+
+ 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 && (Ptr->first == Empty || Ptr->first == Tombstone))
+ ++Ptr;
+ }
+};
+
+template<typename KeyT, typename ValueT, typename KeyInfoT>
+class DenseMapConstIterator : public DenseMapIterator<KeyT, ValueT, KeyInfoT> {
+public:
+ DenseMapConstIterator(const std::pair<KeyT, ValueT> *Pos,
+ const std::pair<KeyT, ValueT> *E)
+ : DenseMapIterator<KeyT, ValueT, KeyInfoT>(Pos, E) {
+ }
+ const std::pair<KeyT, ValueT> &operator*() const {
+ return *this->Ptr;
+ }
+ const std::pair<KeyT, ValueT> *operator->() const {
+ return this->Ptr;
+ }
+};
+
} // end namespace llvm
#endif
projects / oota-llvm.git / blobdiff