-//===- DenseMap.h - A dense map implmentation -------------------*- C++ -*-===//
-//
+//===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
+// 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 implements a dense map. A dense map template takes two
-// types. The first is the mapped type and the second is a functor
-// that maps its argument to a size_t. On instantiation a "null" value
-// can be provided to be used as a "does not exist" indicator in the
-// map. A member function grow() is provided that given the value of
-// the maximally indexed key (the argument of the functor) makes sure
-// the map has enough space for it.
+// This file defines the DenseMap class.
//
//===----------------------------------------------------------------------===//
-#ifndef SUPPORT_DENSEMAP_H
-#define SUPPORT_DENSEMAP_H
+#ifndef LLVM_ADT_DENSEMAP_H
+#define LLVM_ADT_DENSEMAP_H
-#include <vector>
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/MathExtras.h"
+#include <cassert>
+#include <utility>
namespace llvm {
+
+template<typename T>
+struct DenseMapKeyInfo {
+ //static inline T getEmptyKey();
+ //static inline T getTombstoneKey();
+ //static unsigned getHashValue(const T &Val);
+ //static bool isPod()
+};
- struct IdentityFunctor : std::unary_function<unsigned, unsigned> {
- unsigned operator()(unsigned Index) const {
- return Index;
- }
- };
+// Provide DenseMapKeyInfo for all pointers.
+template<typename T>
+struct DenseMapKeyInfo<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);
+ }
+ static bool isPod() { return true; }
+};
- template <typename T, typename ToIndexT = IdentityFunctor>
- class DenseMap {
- typedef typename ToIndexT::argument_type IndexT;
- typedef std::vector<T> StorageT;
- StorageT storage_;
- T nullVal_;
- ToIndexT toIndex_;
+template<typename T>
+struct DenseMapValueInfo {
+ //static bool isPod()
+};
- public:
- DenseMap() : nullVal_(T()) { }
+// Provide DenseMapValueInfo for all pointers.
+template<typename T>
+struct DenseMapValueInfo<T*> {
+ static bool isPod() { return true; }
+};
- explicit DenseMap(const T& val) : nullVal_(val) { }
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT>,
+ typename ValueInfoT = DenseMapValueInfo<ValueT> >
+class DenseMapIterator;
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT>,
+ typename ValueInfoT = DenseMapValueInfo<ValueT> >
+class DenseMapConstIterator;
- typename StorageT::reference operator[](IndexT n) {
- assert(toIndex_(n) < storage_.size() && "index out of bounds!");
- return storage_[toIndex_(n)];
+template<typename KeyT, typename ValueT,
+ typename KeyInfoT = DenseMapKeyInfo<KeyT>,
+ typename ValueInfoT = DenseMapValueInfo<ValueT> >
+class DenseMap {
+ typedef std::pair<KeyT, ValueT> BucketT;
+ unsigned NumBuckets;
+ BucketT *Buckets;
+
+ unsigned NumEntries;
+ unsigned NumTombstones;
+public:
+ 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)
+ P->second.~ValueT();
+ P->first.~KeyT();
+ }
+ delete[] reinterpret_cast<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() {
+ // 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) {
+ if (P->first != TombstoneKey) {
+ P->second.~ValueT();
+ --NumEntries;
+ }
+ P->first = EmptyKey;
+ }
+ }
+ 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) {
+ 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;
+ 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;
- typename StorageT::const_reference operator[](IndexT n) const {
- assert(toIndex_(n) < storage_.size() && "index out of bounds!");
- return storage_[toIndex_(n)];
+ return InsertIntoBucket(Key, ValueT(), TheBucket)->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 (P->first != EmptyKey && 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 (Buckets[i].first != getEmptyKey() &&
+ 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, 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(Key, TheBucket);
+ }
+ ++NumEntries;
+
+ // If we are writing over a tombstone, remember this.
+ if (TheBucket->first != getEmptyKey())
+ --NumTombstones;
+
+ TheBucket->first = Key;
+ new (&TheBucket->second) ValueT(Value);
+ return TheBucket;
+ }
- void clear() {
- storage_.clear();
+ static unsigned getHashValue(const KeyT &Val) {
+ return KeyInfoT::getHashValue(Val);
+ }
+ static const KeyT getEmptyKey() {
+ return KeyInfoT::getEmptyKey();
+ }
+ static const KeyT getTombstoneKey() {
+ return KeyInfoT::getTombstoneKey();
+ }
+
+ /// 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.
+ bool LookupBucketFor(const KeyT &Val, BucketT *&FoundBucket) const {
+ unsigned BucketNo = getHashValue(Val);
+ unsigned ProbeAmt = 1;
+ BucketT *BucketsPtr = Buckets;
+
+ // FoundTombstone - Keep track of whether we find a tombstone while probing.
+ BucketT *FoundTombstone = 0;
+ const KeyT EmptyKey = getEmptyKey();
+ const KeyT TombstoneKey = getTombstoneKey();
+ assert(Val != EmptyKey && 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) {
+ 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 we've already seen a tombstone while probing, fill it in instead
+ // of the empty bucket we eventually probed to.
+ if (FoundTombstone) ThisBucket = FoundTombstone;
+ 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 (ThisBucket->first == TombstoneKey && !FoundTombstone)
+ FoundTombstone = ThisBucket; // Remember the first tombstone found.
+
+ // Otherwise, it's a hash collision or a tombstone, continue quadratic
+ // probing.
+ BucketNo += ProbeAmt++;
}
+ }
+
+ 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 = 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() {
+ unsigned OldNumBuckets = NumBuckets;
+ BucketT *OldBuckets = Buckets;
+
+ // Double the number of buckets.
+ NumBuckets <<= 1;
+ NumTombstones = 0;
+ Buckets = reinterpret_cast<BucketT*>(new char[sizeof(BucketT)*NumBuckets]);
- void grow(IndexT n) {
- unsigned NewSize = toIndex_(n) + 1;
- if (NewSize > storage_.size())
- storage_.resize(NewSize, nullVal_);
+ // 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);
+
+ // 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) {
+ // Insert the key/value into the new table.
+ BucketT *DestBucket;
+ bool FoundVal = LookupBucketFor(B->first, DestBucket);
+ FoundVal = FoundVal; // silence warning.
+ assert(!FoundVal && "Key already in new map?");
+ DestBucket->first = B->first;
+ new (&DestBucket->second) ValueT(B->second);
+
+ // Free the value.
+ B->second.~ValueT();
+ }
+ B->first.~KeyT();
}
+
+ // Free the old table.
+ 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);
- typename StorageT::size_type size() const {
- return storage_.size();
+ // Free the old buckets.
+ const KeyT TombstoneKey = getTombstoneKey();
+ for (BucketT *B = OldBuckets, *E = OldBuckets+OldNumBuckets; B != E; ++B) {
+ if (B->first != EmptyKey && 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, typename KeyInfoT, typename ValueInfoT>
+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, 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, KeyInfoT>(Pos, E) {
+ }
+ const std::pair<KeyT, ValueT> &operator*() const {
+ return *this->Ptr;
+ }
+ const std::pair<KeyT, ValueT> *operator->() const {
+ return this->Ptr;
+ }
+};
-} // End llvm namespace
+} // end namespace llvm
#endif
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