LCOV - code coverage report
Current view: top level - include/llvm/ADT - ScopedHashTable.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 40 40 100.0 %
Date: 2017-09-14 15:23:50 Functions: 21 21 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- ScopedHashTable.h - A simple scoped hash table -----------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This file implements an efficient scoped hash table, which is useful for
      11             : // things like dominator-based optimizations.  This allows clients to do things
      12             : // like this:
      13             : //
      14             : //  ScopedHashTable<int, int> HT;
      15             : //  {
      16             : //    ScopedHashTableScope<int, int> Scope1(HT);
      17             : //    HT.insert(0, 0);
      18             : //    HT.insert(1, 1);
      19             : //    {
      20             : //      ScopedHashTableScope<int, int> Scope2(HT);
      21             : //      HT.insert(0, 42);
      22             : //    }
      23             : //  }
      24             : //
      25             : // Looking up the value for "0" in the Scope2 block will return 42.  Looking
      26             : // up the value for 0 before 42 is inserted or after Scope2 is popped will
      27             : // return 0.
      28             : //
      29             : //===----------------------------------------------------------------------===//
      30             : 
      31             : #ifndef LLVM_ADT_SCOPEDHASHTABLE_H
      32             : #define LLVM_ADT_SCOPEDHASHTABLE_H
      33             : 
      34             : #include "llvm/ADT/DenseMap.h"
      35             : #include "llvm/ADT/DenseMapInfo.h"
      36             : #include "llvm/Support/Allocator.h"
      37             : #include <cassert>
      38             : #include <new>
      39             : 
      40             : namespace llvm {
      41             : 
      42             : template <typename K, typename V, typename KInfo = DenseMapInfo<K>,
      43             :           typename AllocatorTy = MallocAllocator>
      44             : class ScopedHashTable;
      45             : 
      46             : template <typename K, typename V>
      47             : class ScopedHashTableVal {
      48             :   ScopedHashTableVal *NextInScope;
      49             :   ScopedHashTableVal *NextForKey;
      50             :   K Key;
      51             :   V Val;
      52             : 
      53     3784454 :   ScopedHashTableVal(const K &key, const V &val) : Key(key), Val(val) {}
      54             : 
      55             : public:
      56     3784454 :   const K &getKey() const { return Key; }
      57             :   const V &getValue() const { return Val; }
      58             :   V &getValue() { return Val; }
      59             : 
      60             :   ScopedHashTableVal *getNextForKey() { return NextForKey; }
      61             :   const ScopedHashTableVal *getNextForKey() const { return NextForKey; }
      62             :   ScopedHashTableVal *getNextInScope() { return NextInScope; }
      63             : 
      64             :   template <typename AllocatorTy>
      65     3780241 :   static ScopedHashTableVal *Create(ScopedHashTableVal *nextInScope,
      66             :                                     ScopedHashTableVal *nextForKey,
      67             :                                     const K &key, const V &val,
      68             :                                     AllocatorTy &Allocator) {
      69     3788667 :     ScopedHashTableVal *New = Allocator.template Allocate<ScopedHashTableVal>();
      70             :     // Set up the value.
      71     7568908 :     new (New) ScopedHashTableVal(key, val);
      72     3784454 :     New->NextInScope = nextInScope;
      73     3784454 :     New->NextForKey = nextForKey;
      74     3780241 :     return New;
      75             :   }
      76             : 
      77             :   template <typename AllocatorTy> void Destroy(AllocatorTy &Allocator) {
      78             :     // Free memory referenced by the item.
      79             :     this->~ScopedHashTableVal();
      80     3788667 :     Allocator.Deallocate(this);
      81             :   }
      82             : };
      83             : 
      84             : template <typename K, typename V, typename KInfo = DenseMapInfo<K>,
      85             :           typename AllocatorTy = MallocAllocator>
      86             : class ScopedHashTableScope {
      87             :   /// HT - The hashtable that we are active for.
      88             :   ScopedHashTable<K, V, KInfo, AllocatorTy> &HT;
      89             : 
      90             :   /// PrevScope - This is the scope that we are shadowing in HT.
      91             :   ScopedHashTableScope *PrevScope;
      92             : 
      93             :   /// LastValInScope - This is the last value that was inserted for this scope
      94             :   /// or null if none have been inserted yet.
      95             :   ScopedHashTableVal<K, V> *LastValInScope;
      96             : 
      97             : public:
      98             :   ScopedHashTableScope(ScopedHashTable<K, V, KInfo, AllocatorTy> &HT);
      99             :   ScopedHashTableScope(ScopedHashTableScope &) = delete;
     100             :   ScopedHashTableScope &operator=(ScopedHashTableScope &) = delete;
     101             :   ~ScopedHashTableScope();
     102             : 
     103             :   ScopedHashTableScope *getParentScope() { return PrevScope; }
     104             :   const ScopedHashTableScope *getParentScope() const { return PrevScope; }
     105             : 
     106             : private:
     107             :   friend class ScopedHashTable<K, V, KInfo, AllocatorTy>;
     108             : 
     109             :   ScopedHashTableVal<K, V> *getLastValInScope() {
     110             :     return LastValInScope;
     111             :   }
     112             : 
     113             :   void setLastValInScope(ScopedHashTableVal<K, V> *Val) {
     114     3784454 :     LastValInScope = Val;
     115             :   }
     116             : };
     117             : 
     118             : template <typename K, typename V, typename KInfo = DenseMapInfo<K>>
     119             : class ScopedHashTableIterator {
     120             :   ScopedHashTableVal<K, V> *Node;
     121             : 
     122             : public:
     123             :   ScopedHashTableIterator(ScopedHashTableVal<K, V> *node) : Node(node) {}
     124             : 
     125             :   V &operator*() const {
     126             :     assert(Node && "Dereference end()");
     127             :     return Node->getValue();
     128             :   }
     129             :   V *operator->() const {
     130             :     return &Node->getValue();
     131             :   }
     132             : 
     133             :   bool operator==(const ScopedHashTableIterator &RHS) const {
     134             :     return Node == RHS.Node;
     135             :   }
     136             :   bool operator!=(const ScopedHashTableIterator &RHS) const {
     137             :     return Node != RHS.Node;
     138             :   }
     139             : 
     140             :   inline ScopedHashTableIterator& operator++() {          // Preincrement
     141             :     assert(Node && "incrementing past end()");
     142             :     Node = Node->getNextForKey();
     143             :     return *this;
     144             :   }
     145             :   ScopedHashTableIterator operator++(int) {        // Postincrement
     146             :     ScopedHashTableIterator tmp = *this; ++*this; return tmp;
     147             :   }
     148             : };
     149             : 
     150             : template <typename K, typename V, typename KInfo, typename AllocatorTy>
     151             : class ScopedHashTable {
     152             : public:
     153             :   /// ScopeTy - This is a helpful typedef that allows clients to get easy access
     154             :   /// to the name of the scope for this hash table.
     155             :   using ScopeTy = ScopedHashTableScope<K, V, KInfo, AllocatorTy>;
     156             :   using size_type = unsigned;
     157             : 
     158             : private:
     159             :   friend class ScopedHashTableScope<K, V, KInfo, AllocatorTy>;
     160             : 
     161             :   using ValTy = ScopedHashTableVal<K, V>;
     162             : 
     163             :   DenseMap<K, ValTy*, KInfo> TopLevelMap;
     164             :   ScopeTy *CurScope = nullptr;
     165             : 
     166             :   AllocatorTy Allocator;
     167             : 
     168             : public:
     169     1066355 :   ScopedHashTable() = default;
     170             :   ScopedHashTable(AllocatorTy A) : Allocator(A) {}
     171             :   ScopedHashTable(const ScopedHashTable &) = delete;
     172             :   ScopedHashTable &operator=(const ScopedHashTable &) = delete;
     173             : 
     174      143194 :   ~ScopedHashTable() {
     175             :     assert(!CurScope && TopLevelMap.empty() && "Scope imbalance!");
     176     1066019 :   }
     177             : 
     178             :   /// Access to the allocator.
     179             :   AllocatorTy &getAllocator() { return Allocator; }
     180             :   const AllocatorTy &getAllocator() const { return Allocator; }
     181             : 
     182             :   /// Return 1 if the specified key is in the table, 0 otherwise.
     183             :   size_type count(const K &Key) const {
     184     3728416 :     return TopLevelMap.count(Key);
     185             :   }
     186             : 
     187     2359029 :   V lookup(const K &Key) const {
     188     2359029 :     auto I = TopLevelMap.find(Key);
     189     4718058 :     if (I != TopLevelMap.end())
     190      732655 :       return I->second->getValue();
     191             : 
     192        6402 :     return V();
     193             :   }
     194             : 
     195             :   void insert(const K &Key, const V &Val) {
     196     3784454 :     insertIntoScope(CurScope, Key, Val);
     197             :   }
     198             : 
     199             :   using iterator = ScopedHashTableIterator<K, V, KInfo>;
     200             : 
     201             :   iterator end() { return iterator(0); }
     202             : 
     203             :   iterator begin(const K &Key) {
     204             :     typename DenseMap<K, ValTy*, KInfo>::iterator I =
     205             :       TopLevelMap.find(Key);
     206             :     if (I == TopLevelMap.end()) return end();
     207             :     return iterator(I->second);
     208             :   }
     209             : 
     210             :   ScopeTy *getCurScope() { return CurScope; }
     211             :   const ScopeTy *getCurScope() const { return CurScope; }
     212             : 
     213             :   /// insertIntoScope - This inserts the specified key/value at the specified
     214             :   /// (possibly not the current) scope.  While it is ok to insert into a scope
     215             :   /// that isn't the current one, it isn't ok to insert *underneath* an existing
     216             :   /// value of the specified key.
     217     3784454 :   void insertIntoScope(ScopeTy *S, const K &Key, const V &Val) {
     218             :     assert(S && "No scope active!");
     219     7568908 :     ScopedHashTableVal<K, V> *&KeyEntry = TopLevelMap[Key];
     220     3788667 :     KeyEntry = ValTy::Create(S->getLastValInScope(), KeyEntry, Key, Val,
     221             :                              Allocator);
     222     7568908 :     S->setLastValInScope(KeyEntry);
     223     3784454 :   }
     224             : };
     225             : 
     226             : /// ScopedHashTableScope ctor - Install this as the current scope for the hash
     227             : /// table.
     228             : template <typename K, typename V, typename KInfo, typename Allocator>
     229     1433987 : ScopedHashTableScope<K, V, KInfo, Allocator>::
     230     1433987 :   ScopedHashTableScope(ScopedHashTable<K, V, KInfo, Allocator> &ht) : HT(ht) {
     231     1433987 :   PrevScope = HT.CurScope;
     232     1433987 :   HT.CurScope = this;
     233     1433987 :   LastValInScope = nullptr;
     234             : }
     235             : 
     236             : template <typename K, typename V, typename KInfo, typename Allocator>
     237     1433987 : ScopedHashTableScope<K, V, KInfo, Allocator>::~ScopedHashTableScope() {
     238             :   assert(HT.CurScope == this && "Scope imbalance!");
     239     1433987 :   HT.CurScope = PrevScope;
     240             : 
     241             :   // Pop and delete all values corresponding to this scope.
     242     5218441 :   while (ScopedHashTableVal<K, V> *ThisEntry = LastValInScope) {
     243             :     // Pop this value out of the TopLevelMap.
     244     3784454 :     if (!ThisEntry->getNextForKey()) {
     245             :       assert(HT.TopLevelMap[ThisEntry->getKey()] == ThisEntry &&
     246             :              "Scope imbalance!");
     247     5681516 :       HT.TopLevelMap.erase(ThisEntry->getKey());
     248             :     } else {
     249     1887392 :       ScopedHashTableVal<K, V> *&KeyEntry = HT.TopLevelMap[ThisEntry->getKey()];
     250             :       assert(KeyEntry == ThisEntry && "Scope imbalance!");
     251      943696 :       KeyEntry = ThisEntry->getNextForKey();
     252             :     }
     253             : 
     254             :     // Pop this value out of the scope.
     255     3784454 :     LastValInScope = ThisEntry->getNextInScope();
     256             : 
     257             :     // Delete this entry.
     258     3784454 :     ThisEntry->Destroy(HT.getAllocator());
     259             :   }
     260     1433987 : }
     261             : 
     262             : } // end namespace llvm
     263             : 
     264             : #endif // LLVM_ADT_SCOPEDHASHTABLE_H

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