SunPro 5.15 supports `-std=c++14` and several C++14 features.
SunPro 5.14 accepts `-std=c++14` but does not update its definition of
`__cplusplus` or any other macro to distinguish it from `-std=c++11`,
so we need to blacklist a couple features that do work but that we
cannot report for that version. We can still support `cxx_std_14`.
Co-Author: Robert Maynard <robert.maynard@kitware.com>
Previously compilers that only supported the meta-level flags
would not have any of the granular features listed. Now we
presume that they have full support and enable all the features.
Update granular feature tests to skip the actual compilation
checks for the presumed features.
`AddRequiredTargetC(xx)` feature didn't take the default compiler
standard into account, which possibly resulted in the use of an older
standard when some features requested it.
Fixes: #18686
Rather than repeating compiler version checks for feature availability,
generate genex expectations using the detect list of features. We
already separately verify that the list of features is correct.
8570dc7f64 Help: Update compiler versions in cmake-compile-features.7.rst
874d3d2948 Help: Add release note for C++ 20 support
7f295b1bd3 Features: Activate C++ 20 support for Clang 5.0+
71cb8ce3a1 Features: Activate C++ 20 support for GNU 8.0+
8f146c4508 Features: Activate C++ 20 support for MSVC 19.12.25835+
7fe580a362 Features: Add infrastructure for C++ 20 language standard
1b328e09a3 Features: Use -std=c++17 for C++ 17 on Clang 5.0+
0bc3e5788a Features: Use -std=c++17 for C++ 17 on GNU 8.0+
Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !1892
The MSVC C compiler has no notion of C language standards or flags.
Tell CMake to assume that all language standards are available.
Record available C language features depending on the version of
the compiler.
Fixes: #17858
When `CXX_STANDARD` is not at least 14 or 17, features enabled by the
compiler for those standards should not be reported as existing by the
`COMPILE_FEATURES` genex. Fix the implementation and add a test.
Everything in there guards against unsupported compilers already, so no need to
skip the whole file if no features are defined. This in turn allows to have a
simpler fallback in case there is no C++ auto_type feature available.
The `cxx_static_assert` feature may be available in C++ 98 mode of some
compilers or not available at all in others. Intstead of using an
individual feature to test propagation of a feature requiring C++ 11,
use the `std_cxx_11` meta-feature that has exactly this meaning.
A common use case of `target_compile_features` is simply to specify that
the compiler should be run in a mode that is aware of e.g. C++11. Some
projects simply specify a particular C++11-only feature to request this.
Provide a first-class way to do this by naming features after the
corresponding language standard. Record them as always available in the
corresponding standard level so that requesting them always ensures that
standard (or higher) is used.
This bug caused c_function_prototypes to not be recorded at configure
time when compiling with -std=gnu99 or similar. In the case of feature
recording, that was not a problem, because the logic in
CMakeDetermineCompileFeatures.cmake currently assumes that a feature
present for an earlier standard is present for a later standard.
However, the detection strings are also used in WriteCompilerDetectionHeader,
so the feature macro has been defined to '0' when using a later language
dialect.
Fix that by not checking the existence of the __STDC_VERSION__ macro at
all when detecting C90 features.
Define an empty string in CMAKE_<LANG>_STANDARD_DEFAULT to mean that
the toolchain has no notion of lanuage standard levels. In this case
the <LANG>_STANDARD[_REQUIRED] properties will have no effect.
Update the RunCMake.CompileFeatures test to exclude the
LinkImplementationFeatureCycle test when there is no standard default.
It can never fail because no use of specific features will adjust the
CXX_STANDARD level required for any target since the standard levels
have no meaning in this case.
965a50dc Features: Fix GNU 4.4 and 4.5 C standard level flags
7f4154a4 Features: Fix CompileFeatures non-feature tests for space in path
f40c19b5 Features: Fix CompileFeatures test for C non-features
Fix the <lang>_non_features try_compile calls to work correctly when
there is a space in the path. Otherwise they all fail due to the space
instead of the lack of a feature.
004e1540 Features: Record for GNU 4.4.
2a5ca650 Features: Wrap failure-test in UNIX condition.
1ae2c6b2 Features: Blacklist cxx_constexpr test for GNU 4.5.
c66e3317 Features: Use a more-common feature in cycle-test.
c43a6dc5 Features: Update comment in test to match the code.
78259135 Features: Test presence of cxx_auto_type with genex.
7b9fc88b Features: Remove outdated comment.
The purpose of that test is to cover the case where the genex
reports '1', and the feature is chosen to be present on all/most
supported compilers. GNU 4.4 does not support cxx_nullptr.
Because not all compilers under test support the existing 'activation
features', add another test to ensure that compilers which support
both static_assert and nullptr behave as expected in this test.
The purpose of the feature listing in these tests is to make other
features from the same feature set (eg "C++11 features") available.
The compilers under test until now have supported these 'activation
features', but MSVC does not. Use the cxx_static_assert feature
instead to activate the feature set.
The tests below test the presence of both cxx_final and cxx_override,
only one of which is supported by MSVC. The test is in part intended
to verify that the COMPILE_FEATURES genex supports multiple arguments
and allows users to define names for groups of features (Clang already
calls cxx_final and cxx_override 'override control' as a group). Keep
the test, and allow the expectation to be set as appropriate.
Clang 3.4 uses C99 by default, and Clang 3.6 uses C11 by default:
http://thread.gmane.org/gmane.comp.compilers.clang.devel/39379
GNU 4.9 uses C90 by default, and GNU 5.0 uses C11 by default:
https://gcc.gnu.org/gcc-5/changes.html
Test that the default compiler settings result in the expected dialect
macros being defined for both C and CXX. Remove the unused main.c
file from the CompileFeatures unit test.
Aaron Liu