fix crash in SmallDenseMap copy constructor

Prevent a crash in the SmallDenseMap copy constructor whenever the other
map is not in small mode.

<rdar://problem/14292693>

llvm-svn: 202206

2 files changed, 29 insertions, 1 deletions

diff --git a/llvm/include/llvm/ADT/DenseMap.h b/llvm/include/llvm/ADT/DenseMap.h
index ce322cce4e0..0e5d343ac68 100644
--- a/llvm/include/llvm/ADT/DenseMap.h
+++ b/llvm/include/llvm/ADT/DenseMap.h
@@ -830,7 +830,7 @@ public:
     Small = true;
     if (other.getNumBuckets() > InlineBuckets) {
       Small = false;
-      allocateBuckets(other.getNumBuckets());
+      new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
     }
     this->BaseT::copyFrom(other);
   }
diff --git a/llvm/unittests/ADT/DenseMapTest.cpp b/llvm/unittests/ADT/DenseMapTest.cpp
index fa5d0f2e9ea..dd4907104dc 100644
--- a/llvm/unittests/ADT/DenseMapTest.cpp
+++ b/llvm/unittests/ADT/DenseMapTest.cpp
@@ -209,6 +209,34 @@ TYPED_TEST(DenseMapTest, CopyConstructorTest) {
   EXPECT_EQ(this->getValue(), copyMap[this->getKey()]);
 }
 
+// Test copy constructor method where SmallDenseMap isn't small.
+TYPED_TEST(DenseMapTest, CopyConstructorNotSmallTest) {
+  for (int Key = 0; Key < 5; ++Key)
+    this->Map[this->getKey(Key)] = this->getValue(Key);
+  TypeParam copyMap(this->Map);
+
+  EXPECT_EQ(5u, copyMap.size());
+  for (int Key = 0; Key < 5; ++Key)
+    EXPECT_EQ(this->getValue(Key), copyMap[this->getKey(Key)]);
+}
+
+// Test copying from a default-constructed map.
+TYPED_TEST(DenseMapTest, CopyConstructorFromDefaultTest) {
+  TypeParam copyMap(this->Map);
+
+  EXPECT_TRUE(copyMap.empty());
+}
+
+// Test copying from an empty map where SmallDenseMap isn't small.
+TYPED_TEST(DenseMapTest, CopyConstructorFromEmptyTest) {
+  for (int Key = 0; Key < 5; ++Key)
+    this->Map[this->getKey(Key)] = this->getValue(Key);
+  this->Map.clear();
+  TypeParam copyMap(this->Map);
+
+  EXPECT_TRUE(copyMap.empty());
+}
+
 // Test assignment operator method
 TYPED_TEST(DenseMapTest, AssignmentTest) {
   this->Map[this->getKey()] = this->getValue();