From 94f5032aedbd49e2f828e2bb31c006332c2bcaa7 Mon Sep 17 00:00:00 2001
From: Zachary Turner <zturner@google.com>
Date: Fri, 27 Oct 2017 21:12:28 +0000
Subject: [PATCH] Force #define GTEST_LANG_CXX11.

gtest depends on this #define to determine whether it can
use various classes like std::tuple, or whether it has to fall
back to experimental classes in the std::tr1 namespace.  The
check in the current version of gtest relies on the value of
the `__cplusplus` macro, but MSVC provides a non-conformant
value of this macro, making it effectively impossible to detect
C++11.  In short, LLVM compiled with MSVC has been silently
using the tr1 versions of several classes since the beginning of
time.

This would normally be pretty benign, except that in the latest
preview of MSVC they have marked all of the tr1 classes
deprecated, so it spews thousands of warnings.

llvm-svn: 316798
---
 llvm/cmake/modules/AddLLVM.cmake        | 7 +++++++
 llvm/lib/Testing/Support/CMakeLists.txt | 3 +++
 llvm/utils/unittest/CMakeLists.txt      | 5 +++++
 3 files changed, 15 insertions(+)

diff --git a/llvm/cmake/modules/AddLLVM.cmake b/llvm/cmake/modules/AddLLVM.cmake
index 3952d041344b..f52b1c44ab27 100644
--- a/llvm/cmake/modules/AddLLVM.cmake
+++ b/llvm/cmake/modules/AddLLVM.cmake
@@ -1037,6 +1037,13 @@ function(add_unittest test_suite test_name)
     set(EXCLUDE_FROM_ALL ON)
   endif()
 
+  # Our current version of gtest does not properly recognize C++11 support
+  # with MSVC, so it falls back to tr1 / experimental classes.  Since LLVM
+  # itself requires C++11, we can safely force it on unconditionally so that
+  # we don't have to fight with the buggy gtest check.  
+  add_definitions(-DGTEST_LANG_CXX11=1)
+  add_definitions(-DGTEST_HAS_TR1_TUPLE=0)
+
   include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googletest/include)
   include_directories(${LLVM_MAIN_SRC_DIR}/utils/unittest/googlemock/include)
   if (NOT LLVM_ENABLE_THREADS)
diff --git a/llvm/lib/Testing/Support/CMakeLists.txt b/llvm/lib/Testing/Support/CMakeLists.txt
index fa8dfe59c8bd..8ab6fd9a25af 100644
--- a/llvm/lib/Testing/Support/CMakeLists.txt
+++ b/llvm/lib/Testing/Support/CMakeLists.txt
@@ -1,3 +1,6 @@
+add_definitions(-DGTEST_LANG_CXX11=1)
+add_definitions(-DGTEST_HAS_TR1_TUPLE=0)
+
 add_llvm_library(LLVMTestingSupport
   Error.cpp
 
diff --git a/llvm/utils/unittest/CMakeLists.txt b/llvm/utils/unittest/CMakeLists.txt
index b42ac834e3a7..5b5cbf5d745f 100644
--- a/llvm/utils/unittest/CMakeLists.txt
+++ b/llvm/utils/unittest/CMakeLists.txt
@@ -19,6 +19,11 @@ include_directories(
   googlemock
   )
 
+# LLVM requires C++11 but gtest doesn't correctly detect the availability
+# of C++11 on MSVC, so we force it on.
+add_definitions(-DGTEST_LANG_CXX11=1)
+add_definitions(-DGTEST_HAS_TR1_TUPLE=0)
+
 if(WIN32)
   add_definitions(-DGTEST_OS_WINDOWS=1)
 endif()