1 files changed, 67 insertions, 20 deletions

diff --git a/include/llvm/ADT/MapVector.h b/include/llvm/ADT/MapVector.h
index 2eae22c..14c49c5 100644
--- a/include/llvm/ADT/MapVector.h
+++ b/include/llvm/ADT/MapVector.h
@@ -37,26 +37,20 @@ class MapVector {
 public:
   typedef typename VectorType::iterator iterator;
   typedef typename VectorType::const_iterator const_iterator;
+  typedef typename VectorType::reverse_iterator reverse_iterator;
+  typedef typename VectorType::const_reverse_iterator const_reverse_iterator;
 
-  size_type size() const {
-    return Vector.size();
-  }
-
-  iterator begin() {
-    return Vector.begin();
-  }
-
-  const_iterator begin() const {
-    return Vector.begin();
-  }
+  size_type size() const { return Vector.size(); }
 
-  iterator end() {
-    return Vector.end();
-  }
+  iterator begin() { return Vector.begin(); }
+  const_iterator begin() const { return Vector.begin(); }
+  iterator end() { return Vector.end(); }
+  const_iterator end() const { return Vector.end(); }
 
-  const_iterator end() const {
-    return Vector.end();
-  }
+  reverse_iterator rbegin() { return Vector.rbegin(); }
+  const_reverse_iterator rbegin() const { return Vector.rbegin(); }
+  reverse_iterator rend() { return Vector.rend(); }
+  const_reverse_iterator rend() const { return Vector.rend(); }
 
   bool empty() const {
     return Vector.empty();
@@ -125,15 +119,68 @@ public:
   }
 
   /// \brief Remove the element given by Iterator.
+  ///
   /// Returns an iterator to the element following the one which was removed,
   /// which may be end().
+  ///
+  /// \note This is a deceivingly expensive operation (linear time).  It's
+  /// usually better to use \a remove_if() if possible.
   typename VectorType::iterator erase(typename VectorType::iterator Iterator) {
-    typename MapType::iterator MapIterator = Map.find(Iterator->first);
-    Map.erase(MapIterator);
-    return Vector.erase(Iterator);
+    Map.erase(Iterator->first);
+    auto Next = Vector.erase(Iterator);
+    if (Next == Vector.end())
+      return Next;
+
+    // Update indices in the map.
+    size_t Index = Next - Vector.begin();
+    for (auto &I : Map) {
+      assert(I.second != Index && "Index was already erased!");
+      if (I.second > Index)
+        --I.second;
+    }
+    return Next;
   }
+
+  /// \brief Remove all elements with the key value Key.
+  ///
+  /// Returns the number of elements removed.
+  size_type erase(const KeyT &Key) {
+    auto Iterator = find(Key);
+    if (Iterator == end())
+      return 0;
+    erase(Iterator);
+    return 1;
+  }
+
+  /// \brief Remove the elements that match the predicate.
+  ///
+  /// Erase all elements that match \c Pred in a single pass.  Takes linear
+  /// time.
+  template <class Predicate> void remove_if(Predicate Pred);
 };
 
+template <typename KeyT, typename ValueT, typename MapType, typename VectorType>
+template <class Function>
+void MapVector<KeyT, ValueT, MapType, VectorType>::remove_if(Function Pred) {
+  auto O = Vector.begin();
+  for (auto I = O, E = Vector.end(); I != E; ++I) {
+    if (Pred(*I)) {
+      // Erase from the map.
+      Map.erase(I->first);
+      continue;
+    }
+
+    if (I != O) {
+      // Move the value and update the index in the map.
+      *O = std::move(*I);
+      Map[O->first] = O - Vector.begin();
+    }
+    ++O;
+  }
+  // Erase trailing entries in the vector.
+  Vector.erase(O, Vector.end());
 }
 
+} // end namespace llvm
+
 #endif