Filter out `-Wunused-command-line-argument` warnings from Clang (that
can be caused by user-specified flags) so that they do not break our
checks for C++ feature availability.
This extends commit 71b65abca2 (C++ feature checks: Filter out warnings
caused by user flags, 2017-09-19, v3.10.0-rc1~90^2).
Extend commit 78bbd58545 (Source: Link libatomic when needed on Linux
32-bit ARM, 2023-07-27, v3.27.2~10^2) to check for libatomic on more
architectures.
Fixes: #25204
The `remove_filename` and `replace_extension` methods compute an offset
between the whole path in a `std::string` and a part of a path in a
`std::string_view`. This is done by subtracting their `.data()`
pointers. However, C++17 adds a non-const `.data()` through which
modification of the string is allowed. This means the copy-on-write
implementation used by the pre-C++11 std::string GNU ABI must reallocate
if the string has been copied. Our subtraction then computes an offset
between two different allocations, which is undefined behavior.
The workaround in commit b3ca4f9ad1 (cm/filesystem: Work around crash
when compiled for CYGWIN/MSYS runtime, 2021-04-22, v3.21.0-rc1~271^2~2)
avoided the problem by calling the non-const `.data()` to reallocate
before constructing the `string_view`. Instead, explicitly call the
const `.data()` method on the string, which does not reallocate.
Fixes: #22090, #23328
In commit eb583b0a66 (cmake_path command: path management, 2020-07-23,
v3.19.0-rc1~216^2~1) we added a `try_run`. In cross-compilation mode,
C++ features tests must avoid running tests if there is no emulator
defined.
Without this, CMake fails to build on Cray systems with a
craype-hugepages modulefile loaded on the front-end due to libhugetlbfs
warnings breaking the CXX Feature tests. Filter out the warnings so the
bootstrap can proceed to successfully install CMake on Cray Linux
systems.
Fixes: #20645
Require the word "warning" to appear at the start of a line, after
whitespace, or after a `:`. This is the same that CTest launchers use
to match warnings. It avoids matching "warning" inside file paths.
Fixes: #19019
On OpenBSD linking to `libstdc++` with GCC 6.4 always warns:
warning: sprintf() is often misused, please use snprintf()
These do not affect the availability of C++ features we're checking,
so filter them out.
Fixes: #18602
In some environments the linker produces warnings like
warning: directory not found for option
warning: object file compiled with -mlong-branch ...
These do not affect the availability of C++ features we're checking,
so filter them out.
Fixes: #17850, #17947
Use the macro now provided by KWSys instead of using `try_compile`
checks. It will no longer consider the `__attribute__((fallthrough))`
variant, but compilers that don't have one of the modern attributes
shouldn't warn about not using one anyway.
Filter out `-Winvalid-command-line-argument` warnings from Clang (that
can be caused by user-specified flags) so that they do not break our
checks for C++ feature availability.
Simply matching "0 Warning" may match "10 Warning(s)". Instead remove
the entire ` 0 Warning(s)` content from the MSBuild output before
searching it for warnings.
Issue: #16942
The change in commit v3.9.0-rc1~6^2~1 (C++ feature checks: check output
for '[Ww]arning', 2017-06-03) accidentally matches `0 Warning(s)` in the
output and always thinks a warning exists, thus failing all checks in
Visual Studio builds.
Fixes: #16942
When using `CMake_NO_CXX_STANDARD` a user may still provide `-std=c++11`
or similar flags in `CMAKE_CXX_FLAGS`, so we should still check for the
available C++ features.
Turn the feature check for cxx11_unordered_map into a function such that
we can use it for other features as well. Drop the 11 suffix, as we may
want to check features from other standards.
