StringMap: Move assignment and move construction.

llvm-svn: 208361

llvm/include/llvm/ADT/StringMap.h

@@ -53,6 +53,12 @@ protected:
       : TheTable(nullptr),
         // Initialize the map with zero buckets to allocation.
         NumBuckets(0), NumItems(0), NumTombstones(0), ItemSize(itemSize) {}
+  StringMapImpl(StringMapImpl &&RHS) : TheTable(RHS.TheTable), NumBuckets(RHS.NumBuckets), NumItems(RHS.NumItems), NumTombstones(RHS.NumTombstones), ItemSize(RHS.ItemSize) {
+    RHS.TheTable = nullptr;
+    RHS.NumBuckets = 0;
+    RHS.NumItems = 0;
+    RHS.NumTombstones = 0;
+  }
 
   StringMapImpl(unsigned InitSize, unsigned ItemSize);
   void RehashTable();
@@ -233,16 +239,15 @@ public:
       Allocator(A) {}
 
   StringMap(StringMap &&RHS)
-      : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
-    assert(RHS.empty());
-  }
-  StringMap &operator=(StringMap &&RHS) {
-    assert(RHS.empty());
-    clear();
+      : StringMapImpl(std::move(RHS)), Allocator(std::move(RHS.Allocator)) {}
+
+  StringMap &operator=(StringMap RHS) {
+    StringMapImpl::swap(RHS);
+    std::swap(Allocator, RHS.Allocator);
     return *this;
   }
-  StringMap(const StringMap &RHS) LLVM_DELETED_FUNCTION;
-  void operator=(const StringMap &RHS) LLVM_DELETED_FUNCTION;
+
+  // FIXME: Implement copy operations if/when they're needed.
 
   AllocatorTy &getAllocator() { return Allocator; }
   const AllocatorTy &getAllocator() const { return Allocator; }

llvm/unittests/ADT/StringMapTest.cpp

@@ -234,4 +234,71 @@ TEST_F(StringMapTest, MoveOnlyKey) {
   StringMapEntry<MoveOnly>::Create(Key.begin(), Key.end(), MoveOnly(42))->Destroy();
 }
 
+TEST_F(StringMapTest, MoveConstruct) {
+  StringMap<int> A;
+  A.GetOrCreateValue("x", 42);
+  StringMap<int> B = std::move(A);
+  ASSERT_EQ(A.size(), 0u);
+  ASSERT_EQ(B.size(), 1u);
+  ASSERT_EQ(B["x"], 42);
+  ASSERT_EQ(B.count("y"), 0u);
+}
+
+TEST_F(StringMapTest, MoveAssignment) {
+  StringMap<int> A;
+  A["x"] = 42;
+  StringMap<int> B;
+  B["y"] = 117;
+  A = std::move(B);
+  ASSERT_EQ(A.size(), 1u);
+  ASSERT_EQ(B.size(), 0u);
+  ASSERT_EQ(A["y"], 117);
+  ASSERT_EQ(B.count("x"), 0u);
+}
+
+struct Countable {
+  int &InstanceCount;
+  int Number;
+  Countable(int Number, int &InstanceCount) :InstanceCount(InstanceCount), Number(Number) {
+    ++InstanceCount;
+  }
+  Countable(Countable &&C) : InstanceCount(C.InstanceCount), Number(C.Number) {
+    ++InstanceCount;
+    C.Number = -1;
+  }
+  Countable(const Countable &C) : InstanceCount(C.InstanceCount), Number(C.Number) {
+    ++InstanceCount;
+  }
+  Countable &operator=(Countable C) {
+    Number = C.Number;
+    return *this;
+  }
+  ~Countable() {
+    --InstanceCount;
+  }
+
+};
+
+TEST_F(StringMapTest, MoveDtor) {
+  int InstanceCount = 0;
+  StringMap<Countable> A;
+  A.GetOrCreateValue("x", Countable(42, InstanceCount));
+  ASSERT_EQ(InstanceCount, 1);
+  auto I = A.find("x");
+  ASSERT_NE(I, A.end());
+  ASSERT_EQ(I->second.Number, 42);
+
+  StringMap<Countable> B;
+  B = std::move(A);
+  ASSERT_EQ(InstanceCount, 1);
+  ASSERT_TRUE(A.empty());
+  I = B.find("x");
+  ASSERT_NE(I, B.end());
+  ASSERT_EQ(I->second.Number, 42);
+
+  B = StringMap<Countable>();
+  ASSERT_EQ(InstanceCount, 0);
+  ASSERT_TRUE(B.empty());
+}
+
 } // end anonymous namespace