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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316798 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Zachary Turner

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)

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
 

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()