Allow llvm::Optional to work with types without default constructors.

This generalizes Optional to require less from the T type by using aligned
storage for backing & placement new/deleting the T into it when necessary.

Also includes unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175580 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 174 insertions, 0 deletions

diff --git a/unittests/ADT/CMakeLists.txt b/unittests/ADT/CMakeLists.txt
index 0f39e02c1f..9aad793d8b 100644
--- a/unittests/ADT/CMakeLists.txt
+++ b/unittests/ADT/CMakeLists.txt
@@ -19,6 +19,7 @@ set(ADTSources
   IntervalMapTest.cpp
   IntrusiveRefCntPtrTest.cpp
   MapVectorTest.cpp
+  OptionalTest.cpp
   PackedVectorTest.cpp
   SCCIteratorTest.cpp
   SmallPtrSetTest.cpp
diff --git a/unittests/ADT/OptionalTest.cpp b/unittests/ADT/OptionalTest.cpp
new file mode 100644
index 0000000000..8bdea45c5a
--- /dev/null
+++ b/unittests/ADT/OptionalTest.cpp
@@ -0,0 +1,173 @@
+//===- llvm/unittest/ADT/OptionalTest.cpp - Optional unit tests -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "gtest/gtest.h"
+#include "llvm/ADT/Optional.h"
+using namespace llvm;
+
+namespace {
+
+struct NonDefaultConstructible {
+  static unsigned CopyConstructions;
+  static unsigned Destructions;
+  static unsigned CopyAssignments;
+  explicit NonDefaultConstructible(int) {
+  }
+  NonDefaultConstructible(const NonDefaultConstructible&) {
+    ++CopyConstructions;
+  }
+  NonDefaultConstructible &operator=(const NonDefaultConstructible&) {
+    ++CopyAssignments;
+    return *this;
+  }
+  ~NonDefaultConstructible() {
+    ++Destructions;
+  }
+  static void ResetCounts() {
+    CopyConstructions = 0;
+    Destructions = 0;
+    CopyAssignments = 0;
+  }
+};
+
+unsigned NonDefaultConstructible::CopyConstructions = 0;
+unsigned NonDefaultConstructible::Destructions = 0;
+unsigned NonDefaultConstructible::CopyAssignments = 0;
+
+// Test fixture
+class OptionalTest : public testing::Test {
+};
+
+TEST_F(OptionalTest, NonDefaultConstructibleTest) {
+  Optional<NonDefaultConstructible> O;
+  EXPECT_FALSE(O);
+}
+
+TEST_F(OptionalTest, ResetTest) {
+  NonDefaultConstructible::ResetCounts();
+  Optional<NonDefaultConstructible> O(NonDefaultConstructible(3));
+  EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+  NonDefaultConstructible::ResetCounts();
+  O.Reset();
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, InitializationLeakTest) {
+  NonDefaultConstructible::ResetCounts();
+  Optional<NonDefaultConstructible>(NonDefaultConstructible(3));
+  EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(2u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, CopyConstructionTest) {
+  NonDefaultConstructible::ResetCounts();
+  {
+    Optional<NonDefaultConstructible> A(NonDefaultConstructible(3));
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+    Optional<NonDefaultConstructible> B(A);
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+  }
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(2u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, ConstructingCopyAssignmentTest) {
+  NonDefaultConstructible::ResetCounts();
+  {
+    Optional<NonDefaultConstructible> A(NonDefaultConstructible(3));
+    Optional<NonDefaultConstructible> B;
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+    B = A;
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+  }
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(2u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, CopyingCopyAssignmentTest) {
+  NonDefaultConstructible::ResetCounts();
+  {
+    Optional<NonDefaultConstructible> A(NonDefaultConstructible(3));
+    Optional<NonDefaultConstructible> B(NonDefaultConstructible(4));
+    EXPECT_EQ(2u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(2u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+    B = A;
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+  }
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(2u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, DeletingCopyAssignmentTest) {
+  NonDefaultConstructible::ResetCounts();
+  {
+    Optional<NonDefaultConstructible> A;
+    Optional<NonDefaultConstructible> B(NonDefaultConstructible(3));
+    EXPECT_EQ(1u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+    B = A;
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(1u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+  }
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+}
+
+TEST_F(OptionalTest, NullCopyConstructionTest) {
+  NonDefaultConstructible::ResetCounts();
+  {
+    Optional<NonDefaultConstructible> A;
+    Optional<NonDefaultConstructible> B;
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+    B = A;
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+    EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+    EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+    NonDefaultConstructible::ResetCounts();
+  }
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyConstructions);
+  EXPECT_EQ(0u, NonDefaultConstructible::CopyAssignments);
+  EXPECT_EQ(0u, NonDefaultConstructible::Destructions);
+}
+
+} // end anonymous namespace
+