Copy in llvm's DenseMap.h and DenseSet.h

With no modificaions in this commit, so that we can track changes.
Unmodified from llvm rev r230300.

src/core/from_llvm/DenseSet.h

+//===- llvm/ADT/DenseSet.h - Dense probed hash table ------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the DenseSet class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ADT_DENSESET_H
+#define LLVM_ADT_DENSESET_H
+
+#include "llvm/ADT/DenseMap.h"
+
+namespace llvm {
+
+namespace detail {
+struct DenseSetEmpty {};
+
+// Use the empty base class trick so we can create a DenseMap where the buckets
+// contain only a single item.
+template <typename KeyT> class DenseSetPair : public DenseSetEmpty {
+  KeyT key;
+
+public:
+  KeyT &getFirst() { return key; }
+  const KeyT &getFirst() const { return key; }
+  DenseSetEmpty &getSecond() { return *this; }
+  const DenseSetEmpty &getSecond() const { return *this; }
+};
+}
+
+/// DenseSet - This implements a dense probed hash-table based set.
+template<typename ValueT, typename ValueInfoT = DenseMapInfo<ValueT> >
+class DenseSet {
+  typedef DenseMap<ValueT, detail::DenseSetEmpty, ValueInfoT,
+                   detail::DenseSetPair<ValueT>> MapTy;
+  static_assert(sizeof(typename MapTy::value_type) == sizeof(ValueT),
+                "DenseMap buckets unexpectedly large!");
+  MapTy TheMap;
+public:
+  typedef ValueT key_type;
+  typedef ValueT value_type;
+  typedef unsigned size_type;
+
+  explicit DenseSet(unsigned NumInitBuckets = 0) : TheMap(NumInitBuckets) {}
+
+  bool empty() const { return TheMap.empty(); }
+  size_type size() const { return TheMap.size(); }
+  size_t getMemorySize() const { return TheMap.getMemorySize(); }
+
+  /// Grow the DenseSet so that it has at least Size buckets. Will not shrink
+  /// the Size of the set.
+  void resize(size_t Size) { TheMap.resize(Size); }
+
+  void clear() {
+    TheMap.clear();
+  }
+
+  /// Return 1 if the specified key is in the set, 0 otherwise.
+  size_type count(const ValueT &V) const {
+    return TheMap.count(V);
+  }
+
+  bool erase(const ValueT &V) {
+    return TheMap.erase(V);
+  }
+
+  void swap(DenseSet& RHS) {
+    TheMap.swap(RHS.TheMap);
+  }
+
+  // Iterators.
+
+  class Iterator {
+    typename MapTy::iterator I;
+    friend class DenseSet;
+  public:
+    typedef typename MapTy::iterator::difference_type difference_type;
+    typedef ValueT value_type;
+    typedef value_type *pointer;
+    typedef value_type &reference;
+    typedef std::forward_iterator_tag iterator_category;
+
+    Iterator(const typename MapTy::iterator &i) : I(i) {}
+
+    ValueT &operator*() { return I->getFirst(); }
+    ValueT *operator->() { return &I->getFirst(); }
+
+    Iterator& operator++() { ++I; return *this; }
+    bool operator==(const Iterator& X) const { return I == X.I; }
+    bool operator!=(const Iterator& X) const { return I != X.I; }
+  };
+
+  class ConstIterator {
+    typename MapTy::const_iterator I;
+    friend class DenseSet;
+  public:
+    typedef typename MapTy::const_iterator::difference_type difference_type;
+    typedef ValueT value_type;
+    typedef value_type *pointer;
+    typedef value_type &reference;
+    typedef std::forward_iterator_tag iterator_category;
+
+    ConstIterator(const typename MapTy::const_iterator &i) : I(i) {}
+
+    const ValueT &operator*() { return I->getFirst(); }
+    const ValueT *operator->() { return &I->getFirst(); }
+
+    ConstIterator& operator++() { ++I; return *this; }
+    bool operator==(const ConstIterator& X) const { return I == X.I; }
+    bool operator!=(const ConstIterator& X) const { return I != X.I; }
+  };
+
+  typedef Iterator      iterator;
+  typedef ConstIterator const_iterator;
+
+  iterator begin() { return Iterator(TheMap.begin()); }
+  iterator end() { return Iterator(TheMap.end()); }
+
+  const_iterator begin() const { return ConstIterator(TheMap.begin()); }
+  const_iterator end() const { return ConstIterator(TheMap.end()); }
+
+  iterator find(const ValueT &V) { return Iterator(TheMap.find(V)); }
+
+  /// Alternative version of find() which allows a different, and possibly less
+  /// expensive, key type.
+  /// The DenseMapInfo is responsible for supplying methods
+  /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key type
+  /// used.
+  template <class LookupKeyT>
+  iterator find_as(const LookupKeyT &Val) {
+    return Iterator(TheMap.find_as(Val));
+  }
+  template <class LookupKeyT>
+  const_iterator find_as(const LookupKeyT &Val) const {
+    return ConstIterator(TheMap.find_as(Val));
+  }
+
+  void erase(Iterator I) { return TheMap.erase(I.I); }
+  void erase(ConstIterator CI) { return TheMap.erase(CI.I); }
+
+  std::pair<iterator, bool> insert(const ValueT &V) {
+    detail::DenseSetEmpty Empty;
+    return TheMap.insert(std::make_pair(V, Empty));
+  }
+  
+  // Range insertion of values.
+  template<typename InputIt>
+  void insert(InputIt I, InputIt E) {
+    for (; I != E; ++I)
+      insert(*I);
+  }
+};
+
+} // end namespace llvm
+
+#endif