Divert LCC compiler as a new one, instead of treating it as GNU.
Since old times, Elbrus C/C++/Fortran Compiler (LCC) by MCST has been
passing checks for GNU compilers, so it has been identified as GNU.
Now, with intent of seriously upstreaming its support, it has been
added as a separate LCC compiler, and its version displays not a
supported GCC version, but LCC version itself (e.g. LCC 1.25.19 instead
of GNU 7.3.0).
This commit adds its support for detection, and also converts basically
every check like 'is this compiler GNU?' to 'is this compiler GNU or
LCC?'. The only places where this check is untouched, is where it
regards other platforms where LCC is unavailable (primarily non-Linux),
and where it REALLY differs from GNU compiler.
Note: this transition may break software that are already ported to
Elbrus, but hardly relies that LCC will be detected as GNU; still such
software is not known.
For the Intel Compiler for Windows we have some subtle preprocessor
checks in compiler feature detection to detect C++11 and C++14 modes.
Use these when detecting the default C++ dialect too.
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.
The genex part of the test verifies that `$<COMPILE_FEATURES:...>`
evaluates as expected. It does not need to actually try using code with
the associated features, as that is tested separately.
`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
Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`. Use `clang-format` version 6.0.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Update `.clang-format` with configuration to make the 6.0 format as
close as possible to what 3.8 produced before. Then revise the style:
* Indent preprocessor directives (a feature new since 3.8)
* Add a newline and indentation before inheritance `:` and `,`
Rename the Git attribute identifying the format to include the
clang-format version number: `format.clang-format-6.0`. This will aid
external infrastructure in knowing what version of the tool to run.
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
Features recorded by commit v3.6.0-rc1~120^2~5 (Features: Record
standards and features for Intel C++ on UNIX, 2016-04-28) for the Intel
compiler left out initializer list support because our test case in
`Tests/CompileFeatures/cxx_generalized_initializers.cpp` caused an
internal compiler error. It turns out this is because the Intel
compiler asserts the `initializer_list` constructor signatures to verify
that they match its own `<initializer_list>` header. It was our dummy
implementation used to test the language feature without any headers
that caused the ICE. Revise it to use a constructor signature accepted
by the Intel compiler.
Fixes: #17829
`Modules/CMakeCCompilerId.c.in` will report the C dialect as 11 whenever
`__STDC_VERSION__` indicates *at least* C 11. Make the test consistent
with this. We already do this for the C++ case.
Fixes: #17740
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.
Visual Studio 2015 Update 3 introduced the notion of language standard
levels to MSVC. The language standard level is defined in `_MSVC_LANG`
instead of `__cplusplus`. It also added support for the `-std:c++14`
and `-std:c++latest` flags, although the compiler defaults to its C++14
mode anyway. Visual Studio 2017 Update 3 will introduce support for the
`-std:c++17` flag.
Fixes: #16482
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.
The clang-format pass in commit v3.6.0-rc1~54^2~1 (Revise C++ coding
style using clang-format, 2016-05-16) changed the template right angle
brackets from `>>` to `> >`, which defeats the purpose of this test.
Change it back and exclude this content from formatting.
Run the `Utilities/Scripts/clang-format.bash` script to update
all our C++ code to a new style defined by `.clang-format`.
Use `clang-format` version 3.8.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
Since CMake is written in C++98 any clang-format configuration must
set `Standard` to `Cpp03` so that `A<A<int> >` is not rewritten as
`A<A<int>>`. However, this will cause `U"foo"` to be rewritten as
`U "foo"`. Add markup to turn clang-format off in the one place
that the latter case occurs so that we do not need a separate
`.clang-format` config file for it.
Inspired-by: Daniel Pfeifer <daniel@pfeifer-mail.de>
VS 2013 originally claimed to support initializer lists but a bug was
found in which it generated bad code silently. For this reason we
previously considered support to not be present. However, Update 3 adds
a hard error on cases that previously generated bad code, so it is now
safe to use initializer lists with VS 2013 Update 3 or greater. At
worst a compiler error will be issued in the cases that do not work, but
that is no different from any other compiler-specific workaround a
project code may need.
The only reason this failed to compile on VS 2013 was because the
compiler uses different initializer_list constructor argument types than
our dummy implementation. The standard does not specify the non-default
constructor argument types for initializer_list. Use a template to
match any two-arg constructor a compiler might select (e.g. begin/end or
begin/len). Use #error to preserve the error on VS 2013.
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.
