clang-cl is clang for Windows running in MSVC mode. Chromium uses it for
Windows builds. clang-cl is weird in that it defines __clang__ and
_MSC_VER, but *NOT* __GNUC__. This is vaguely analogous to how normal
clang defines __clang__ (what it is) and __GNUC__ (what it is compatible
with).
However, clang-cl still implements most GCC extensions, being clang.
Notably, the way to control -Wformat-literal is still with
__attribute__((__format__)). For better error-checking and strict
-Wformatl-literal compatibility (see
53c478d639b8eebd2942e88266610ebc79c541f6), define
GTEST_ATTRIBUTE_PRINTF_ in clang-cl too.
This makes it easier to use GTest in projects that build with the
-Wmissing-declarations warning. This fixes the warning in headers and
source files, though not GTest's own tests as it is rather noisy there.
On platforms with std::tuple and not std::tr1::tuple, GTEST_HAS_COMBINE
gets turned off when it works fine (due to GTEST_TUPLE_NAMESPACE_).
Elsewhere in the project, several GTEST_HAS_TR1_TUPLE checks
additionally check GTEST_HAS_STD_TUPLE_, so use that formulation.
(The ones that don't are specific to std::tr1::tuple and are followed by
an identical GTEST_HAS_STD_TUPLE_ version underneath it.)
In particular, this fixes testing::Combine on MSVC 2017, which regressed
here:
https://github.com/google/googletest/pull/1348#issuecomment-353879010
This is part (hopefully all) of the fixes for #776. The top-level
configure.ac configures googletest first and then googlemock.
With this changes it is possible to embed googletest into another
project that uses autoconf. For an example (though it is WIP), see
the commits (and soon PR) referenced from google/protobuf#236.
ThreadLocal class needs to be have default visibility.
Root cause is gtest uses typeinfo for the ThreadLocal class.
The problem manifests When gtest/gmock are built as a shared library
with libc++. When a class is used in typeinfo, it must have default
visibility.
There is an explanation about typeinfo and visibility here:
https://developer.apple.com/library/content/documentation/DeveloperTools/Conceptual/CppRuntimeEnv/Articles/SymbolVisibility.html
When libc++ is used with gtest in shared library mode, any tests
that are compiled with -fvisibility=hidden and exercise the
macro EXPECT_CALL, it results in an abort like:
[ FATAL ] /usr/include/gtest/internal/gtest-port.h:1394::
Condition typeid(*base) == typeid(Derived) failed.
This is because the typeinfo for ThreadLocal class is not visible.
Therefore, linker failed to match it to the shared library symbol, creating a
new symbol instead.
This fixes https://github.com/google/googletest/issues/1207.
