Fix bug in UnionIfNotIn.

Bug: 18066207

Change-Id: Ib9b24802546403b3d5a4da19996034eb45601f53

2 files changed, 27 insertions, 4 deletions

diff --git a/runtime/base/bit_vector.cc b/runtime/base/bit_vector.cc
index 3d2f0de..1d67962 100644
--- a/runtime/base/bit_vector.cc
+++ b/runtime/base/bit_vector.cc
@@ -145,10 +145,7 @@ bool BitVector::UnionIfNotIn(const BitVector* union_with, const BitVector* not_i
 
   // Is the storage size smaller than src's?
   if (storage_size_ < union_with_size) {
-    changed = true;
-
-    // Set it to reallocate.
-    SetBit(highest_bit);
+    EnsureSize(highest_bit);
 
     // Paranoid: storage size should be big enough to hold this bit now.
     DCHECK_LT(static_cast<uint32_t> (highest_bit), storage_size_ * kWordBits);
diff --git a/runtime/base/bit_vector_test.cc b/runtime/base/bit_vector_test.cc
index df5d79d..31fd0e7 100644
--- a/runtime/base/bit_vector_test.cc
+++ b/runtime/base/bit_vector_test.cc
@@ -141,4 +141,30 @@ TEST(BitVector, SetInitialBits) {
   EXPECT_EQ(64u, bv.NumSetBits());
 }
 
+TEST(BitVector, UnionIfNotIn) {
+  {
+    BitVector first(2, true, Allocator::GetMallocAllocator());
+    BitVector second(5, true, Allocator::GetMallocAllocator());
+    BitVector third(5, true, Allocator::GetMallocAllocator());
+
+    second.SetBit(64);
+    third.SetBit(64);
+    bool changed = first.UnionIfNotIn(&second, &third);
+    EXPECT_EQ(0u, first.NumSetBits());
+    EXPECT_FALSE(changed);
+  }
+
+  {
+    BitVector first(2, true, Allocator::GetMallocAllocator());
+    BitVector second(5, true, Allocator::GetMallocAllocator());
+    BitVector third(5, true, Allocator::GetMallocAllocator());
+
+    second.SetBit(64);
+    bool changed = first.UnionIfNotIn(&second, &third);
+    EXPECT_EQ(1u, first.NumSetBits());
+    EXPECT_TRUE(changed);
+    EXPECT_TRUE(first.IsBitSet(64));
+  }
+}
+
 }  // namespace art