Summary:
Running the test suite with -a will now properly show all the executed
commands. The reports also include the environment under which the test
is being executed, which is helpful for reproducing issues.
Reviewers: EricWF
Subscribers: christof, dexonsmith, libcxx-commits
Differential Revision: https://reviews.llvm.org/D53215
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@344700 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
The `[[nodiscard]]` attribute is intended to help users find bugs where
function return values are ignored when they shouldn't be. After C++17 the
C++ standard has started to declared such library functions as `[[nodiscard]]`.
However, this application is limited and applies only to dialects after C++17.
Users who want help diagnosing misuses of STL functions may desire a more
liberal application of `[[nodiscard]]`.
For this reason libc++ provides an extension that does just that! The
extension must be enabled by defining `_LIBCPP_ENABLE_NODISCARD`. The extended
applications of `[[nodiscard]]` takes two forms:
1. Backporting `[[nodiscard]]` to entities declared as such by the
standard in newer dialects, but not in the present one.
2. Extended applications of `[[nodiscard]]`, at the libraries discretion,
applied to entities never declared as such by the standard.
Users may also opt-out of additional applications `[[nodiscard]]` using
additional macros.
Applications of the first form, which backport `[[nodiscard]]` from a newer
dialect may be disabled using macros specific to the dialect it was added. For
example `_LIBCPP_DISABLE_NODISCARD_AFTER_CXX17`.
Applications of the second form, which are pure extensions, may be disabled
by defining `_LIBCPP_DISABLE_NODISCARD_EXT`.
This patch was originally written by me (Roman Lebedev),
then but then reworked by Eric Fiselier.
Reviewers: mclow.lists, thakis, EricWF
Reviewed By: thakis, EricWF
Subscribers: llvm-commits, mclow.lists, lebedev.ri, EricWF, rjmccall, Quuxplusone, cfe-commits, christof
Differential Revision: https://reviews.llvm.org/D45179
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342808 91177308-0d34-0410-b5e6-96231b3b80d8
Previously .fail.cpp tests for nodiscard were run with -Wunused-result
being a warning, not an error, when the compiler didn't support -verify.
When -verify isn't enabled this change judiciously adds -Werror=unused-result
when to only the failure tests containing the // expected-error string for nodiscard.
As a drive-by change, this patch also adds a missing // UNSUPPORTED: c++2a to
a test which was only supposed to run in C++ <= 11.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@322776 91177308-0d34-0410-b5e6-96231b3b80d8
