Fix BitVector move ctor/assignment.

[eugenis]

Summary

Current implementation leaves the object in an invalid state.

[dblaikie]

Test coverage?

[eugenis]

In D21423#459571, @dblaikie wrote:

Test coverage?

Of course. Thanks for reminding!

[dblaikie]

Great - thanks!

[eugenis]

r272965

include/llvm/ADT/BitVector.h

BitVector(const BitVector &RHS) : Size(RHS.size()) {
     Capacity = NumBitWords(RHS.size());
     Bits = (BitWord *)std::malloc(Capacity * sizeof(BitWord));
     std::memcpy(Bits, RHS.Bits, Capacity * sizeof(BitWord));
   }
 
   BitVector(BitVector &&RHS)
     : Bits(RHS.Bits), Size(RHS.Size), Capacity(RHS.Capacity) {
     RHS.Bits = nullptr;
+    RHS.Size = RHS.Capacity = 0;
   }
 
   ~BitVector() {
     std::free(Bits);
   }
 
   /// empty - Tests whether there are no bits in this bitvector.
   bool empty() const { return Size == 0; }
const BitVector &operator=(BitVector &&RHS) {
     if (this == &RHS) return *this;
 
     std::free(Bits);
     Bits = RHS.Bits;
     Size = RHS.Size;
     Capacity = RHS.Capacity;
 
     RHS.Bits = nullptr;
+    RHS.Size = RHS.Capacity = 0;
 
     return *this;
   }
 
   void swap(BitVector &RHS) {
     std::swap(Bits, RHS.Bits);
     std::swap(Size, RHS.Size);
     std::swap(Capacity, RHS.Capacity);

unittests/ADT/BitVectorTest.cpp

TYPED_TEST(BitVectorTest, CompoundTestReset) {
   EXPECT_TRUE(A.none());
   A.set();
 
   C.reset(A);
   EXPECT_EQ(50, C.find_first());
   C.reset(C);
   EXPECT_TRUE(C.none());
 }
+
+TYPED_TEST(BitVectorTest, MoveConstructor) {
+  TypeParam A(10, true);
+  TypeParam B(std::move(A));
+  // Check that the move ctor leaves the moved-from object in a valid state.
+  // The following line used to crash.
+  A = B;
+
+  TypeParam C(10, true);
+  EXPECT_EQ(C, A);
+  EXPECT_EQ(C, B);
+}
+
+TYPED_TEST(BitVectorTest, MoveAssignment) {
+  TypeParam A(10, true);
+  TypeParam B;
+  B = std::move(A);
+  // Check that move assignment leaves the moved-from object in a valid state.
+  // The following line used to crash.
+  A = B;
+
+  TypeParam C(10, true);
+  EXPECT_EQ(C, A);
+  EXPECT_EQ(C, B);
+}
+
 }
 #endif