Add a polymorphic_ptr<T> smart pointer data type. It's a somewhat silly

unique ownership smart pointer which is *deep* copyable by assuming it
can call a T::clone() method to allocate a copy of the owned data.

This is mostly useful with containers or other collections of uniquely
owned data in C++98 where they *might* copy. With C++11 we can likely
remove this in favor of move-only types and containers wrapped around
those types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194315 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/ADT/CMakeLists.txt

@@ -35,6 +35,7 @@ set(ADTSources
   TripleTest.cpp
   TwineTest.cpp
   VariadicFunctionTest.cpp
+  polymorphic_ptr_test.cpp
  )
 
 # They cannot be compiled on MSVC9 due to its bug.

unittests/ADT/polymorphic_ptr_test.cpp

@@ -0,0 +1,71 @@
+//===- llvm/unittest/ADT/polymorphic_ptr.h - polymorphic_ptr<T> 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/polymorphic_ptr.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+
+TEST(polymorphic_ptr_test, Basic) {
+  struct S {
+    S(int x) : x(x) {}
+    int x;
+  };
+
+  polymorphic_ptr<S> null;
+  EXPECT_FALSE((bool)null);
+  EXPECT_TRUE(!null);
+  EXPECT_EQ((S*)0, null.get());
+
+  S *s = new S(42);
+  polymorphic_ptr<S> p(s);
+  EXPECT_TRUE((bool)p);
+  EXPECT_FALSE(!p);
+  EXPECT_TRUE(p != null);
+  EXPECT_FALSE(p == null);
+  EXPECT_TRUE(p == s);
+  EXPECT_TRUE(s == p);
+  EXPECT_FALSE(p != s);
+  EXPECT_FALSE(s != p);
+  EXPECT_EQ(s, &*p);
+  EXPECT_EQ(s, p.operator->());
+  EXPECT_EQ(s, p.get());
+  EXPECT_EQ(42, p->x);
+
+  EXPECT_EQ(s, p.take());
+  EXPECT_FALSE((bool)p);
+  EXPECT_TRUE(!p);
+  p = s;
+  EXPECT_TRUE((bool)p);
+  EXPECT_FALSE(!p);
+  EXPECT_EQ(s, &*p);
+  EXPECT_EQ(s, p.operator->());
+  EXPECT_EQ(s, p.get());
+  EXPECT_EQ(42, p->x);
+
+  polymorphic_ptr<S> p2((llvm_move(p)));
+  EXPECT_FALSE((bool)p);
+  EXPECT_TRUE(!p);
+  EXPECT_TRUE((bool)p2);
+  EXPECT_FALSE(!p2);
+  EXPECT_EQ(s, &*p2);
+
+  using std::swap;
+  swap(p, p2);
+  EXPECT_TRUE((bool)p);
+  EXPECT_FALSE(!p);
+  EXPECT_EQ(s, &*p);
+  EXPECT_FALSE((bool)p2);
+  EXPECT_TRUE(!p2);
+}
+
+}