[Support] Port ErrorOr<T> from lld to C++03.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172991 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Support/ErrorOrTest.cpp

@@ -0,0 +1,78 @@
+//===- unittests/ErrorOrTest.cpp - ErrorOr.h tests ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ErrorOr.h"
+
+#include "gtest/gtest.h"
+
+#include <memory>
+
+using namespace llvm;
+
+namespace {
+
+ErrorOr<int> t1() {return 1;}
+ErrorOr<int> t2() {return make_error_code(errc::invalid_argument);}
+
+TEST(ErrorOr, SimpleValue) {
+  ErrorOr<int> a = t1();
+  EXPECT_TRUE(a);
+  EXPECT_EQ(1, *a);
+
+  a = t2();
+  EXPECT_FALSE(a);
+  EXPECT_EQ(errc::invalid_argument, a);
+  EXPECT_DEBUG_DEATH(*a, "Cannot get value when an error exists");
+}
+
+#if LLVM_HAS_CXX11_STDLIB
+ErrorOr<std::unique_ptr<int> > t3() {
+  return std::unique_ptr<int>(new int(3));
+}
+#endif
+
+TEST(ErrorOr, Types) {
+  int x;
+  ErrorOr<int&> a(x);
+  *a = 42;
+  EXPECT_EQ(42, x);
+
+#if LLVM_HAS_CXX11_STDLIB
+  // Move only types.
+  EXPECT_EQ(3, **t3());
+#endif
+}
+} // end anon namespace
+
+struct InvalidArgError {
+  InvalidArgError() {}
+  InvalidArgError(std::string S) : ArgName(S) {}
+  std::string ArgName;
+};
+
+namespace llvm {
+template<>
+struct ErrorOrUserDataTraits<InvalidArgError> : std::true_type {
+  static error_code error() {
+    return make_error_code(errc::invalid_argument);
+  }
+};
+} // end namespace lld
+
+ErrorOr<int> t4() {
+  return InvalidArgError("adena");
+}
+
+namespace {
+TEST(ErrorOr, UserErrorData) {
+  ErrorOr<int> a = t4();
+  EXPECT_EQ(errc::invalid_argument, a);
+  EXPECT_EQ("adena", t4().getError<InvalidArgError>().ArgName);
+}
+} // end anon namespace