| //===- ScopedHashTable.h - A simple scoped hash table ---------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements an efficient scoped hash table, which is useful for |
| // things like dominator-based optimizations. This allows clients to do things |
| // like this: |
| // |
| // ScopedHashTable<int, int> HT; |
| // { |
| // ScopedHashTableScope<int, int> Scope1(HT); |
| // HT.insert(0, 0); |
| // HT.insert(1, 1); |
| // { |
| // ScopedHashTableScope<int, int> Scope2(HT); |
| // HT.insert(0, 42); |
| // } |
| // } |
| // |
| // Looking up the value for "0" in the Scope2 block will return 42. Looking |
| // up the value for 0 before 42 is inserted or after Scope2 is popped will |
| // return 0. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ADT_SCOPEDHASHTABLE_H |
| #define LLVM_ADT_SCOPEDHASHTABLE_H |
| |
| #include <cassert> |
| #include "llvm/ADT/DenseMap.h" |
| |
| namespace llvm { |
| |
| template <typename K, typename V> |
| class ScopedHashTable; |
| |
| template <typename K, typename V> |
| class ScopedHashTableVal { |
| ScopedHashTableVal *NextInScope; |
| ScopedHashTableVal *NextForKey; |
| K Key; |
| V Val; |
| public: |
| ScopedHashTableVal(ScopedHashTableVal *nextInScope, |
| ScopedHashTableVal *nextForKey, const K &key, const V &val) |
| : NextInScope(nextInScope), NextForKey(nextForKey), Key(key), Val(val) { |
| } |
| |
| const K &getKey() const { return Key; } |
| const V &getValue() const { return Val; } |
| V &getValue() { return Val; } |
| |
| ScopedHashTableVal *getNextForKey() { return NextForKey; } |
| const ScopedHashTableVal *getNextForKey() const { return NextForKey; } |
| public: |
| ScopedHashTableVal *getNextInScope() { return NextInScope; } |
| }; |
| |
| template <typename K, typename V> |
| class ScopedHashTableScope { |
| /// HT - The hashtable that we are active for. |
| ScopedHashTable<K, V> &HT; |
| |
| /// PrevScope - This is the scope that we are shadowing in HT. |
| ScopedHashTableScope *PrevScope; |
| |
| /// LastValInScope - This is the last value that was inserted for this scope |
| /// or null if none have been inserted yet. |
| ScopedHashTableVal<K,V> *LastValInScope; |
| void operator=(ScopedHashTableScope&); // DO NOT IMPLEMENT |
| ScopedHashTableScope(ScopedHashTableScope&); // DO NOT IMPLEMENT |
| public: |
| ScopedHashTableScope(ScopedHashTable<K, V> &HT); |
| ~ScopedHashTableScope(); |
| |
| private: |
| friend class ScopedHashTable<K, V>; |
| ScopedHashTableVal<K, V> *getLastValInScope() { return LastValInScope; } |
| void setLastValInScope(ScopedHashTableVal<K,V> *Val) { LastValInScope = Val; } |
| }; |
| |
| |
| template <typename K, typename V> |
| class ScopedHashTableIterator { |
| ScopedHashTableVal<K,V> *Node; |
| public: |
| ScopedHashTableIterator(ScopedHashTableVal<K,V> *node) : Node(node){} |
| |
| V &operator*() const { |
| assert(Node && "Dereference end()"); |
| return Node->getValue(); |
| } |
| V *operator->() const { |
| return &Node->getValue(); |
| } |
| |
| bool operator==(const ScopedHashTableIterator &RHS) const { |
| return Node == RHS.Node; |
| } |
| bool operator!=(const ScopedHashTableIterator &RHS) const { |
| return Node != RHS.Node; |
| } |
| |
| inline ScopedHashTableIterator& operator++() { // Preincrement |
| assert(Node && "incrementing past end()"); |
| Node = Node->getNextForKey(); |
| return *this; |
| } |
| ScopedHashTableIterator operator++(int) { // Postincrement |
| ScopedHashTableIterator tmp = *this; ++*this; return tmp; |
| } |
| }; |
| |
| |
| template <typename K, typename V> |
| class ScopedHashTable { |
| DenseMap<K, ScopedHashTableVal<K,V>*> TopLevelMap; |
| ScopedHashTableScope<K, V> *CurScope; |
| ScopedHashTable(const ScopedHashTable&); // NOT YET IMPLEMENTED |
| void operator=(const ScopedHashTable&); // NOT YET IMPLEMENTED |
| friend class ScopedHashTableScope<K, V>; |
| public: |
| ScopedHashTable() : CurScope(0) {} |
| ~ScopedHashTable() { |
| assert(CurScope == 0 && TopLevelMap.empty() && "Scope imbalance!"); |
| } |
| |
| void insert(const K &Key, const V &Val) { |
| assert(CurScope && "No scope active!"); |
| |
| ScopedHashTableVal<K,V> *&KeyEntry = TopLevelMap[Key]; |
| |
| KeyEntry = new ScopedHashTableVal<K,V>(CurScope->getLastValInScope(), |
| KeyEntry, Key, Val); |
| CurScope->setLastValInScope(KeyEntry); |
| } |
| |
| typedef ScopedHashTableIterator<K, V> iterator; |
| |
| iterator end() { return iterator(0); } |
| |
| iterator begin(const K &Key) { |
| typename DenseMap<K, ScopedHashTableVal<K,V>*>::iterator I = |
| TopLevelMap.find(Key); |
| if (I == TopLevelMap.end()) return end(); |
| return iterator(I->second); |
| } |
| }; |
| |
| /// ScopedHashTableScope ctor - Install this as the current scope for the hash |
| /// table. |
| template <typename K, typename V> |
| ScopedHashTableScope<K, V>::ScopedHashTableScope(ScopedHashTable<K, V> &ht) |
| : HT(ht) { |
| PrevScope = HT.CurScope; |
| HT.CurScope = this; |
| LastValInScope = 0; |
| } |
| |
| template <typename K, typename V> |
| ScopedHashTableScope<K, V>::~ScopedHashTableScope() { |
| assert(HT.CurScope == this && "Scope imbalance!"); |
| HT.CurScope = PrevScope; |
| |
| // Pop and delete all values corresponding to this scope. |
| while (ScopedHashTableVal<K, V> *ThisEntry = LastValInScope) { |
| // Pop this value out of the TopLevelMap. |
| if (ThisEntry->getNextForKey() == 0) { |
| assert(HT.TopLevelMap[ThisEntry->getKey()] == ThisEntry && |
| "Scope imbalance!"); |
| HT.TopLevelMap.erase(ThisEntry->getKey()); |
| } else { |
| ScopedHashTableVal<K,V> *&KeyEntry = HT.TopLevelMap[ThisEntry->getKey()]; |
| assert(KeyEntry == ThisEntry && "Scope imbalance!"); |
| KeyEntry = ThisEntry->getNextForKey(); |
| } |
| |
| // Pop this value out of the scope. |
| LastValInScope = ThisEntry->getNextInScope(); |
| |
| // Delete this entry. |
| delete ThisEntry; |
| } |
| } |
| |
| } // end namespace llvm |
| |
| #endif |