Instead of detecting it automatically but also allowing for the setting
to be specified explicitly, always detect whether exceptions are enabled
based on whether -fno-rtti (or equivalent) is used. It's less confusing
to have a single way of tweaking that knob.
This change follows the lead of 71d88cebfb42.
Instead of having complex logic around how to include the libc++ headers
and __config_site, handle that by defining cxx-headers as an INTERFACE
library and linking against it. After this patch, linking against cxx-headers
is sufficient to get the right __config_site include and include paths
for libc++.
Differential Revision: https://reviews.llvm.org/D82702
Thanks to @lewissbaker who pointed out the unnecessary condition in
https://reviews.llvm.org/D81954#inline-756872. Since this codepath does not
make use of `swap` anyway (that codepath is a different branch), we can safely
remove this condition and produce better codegen when all types are nothrow
movable but are potentially-throwing swappable.
See codegen in https://gcc.godbolt.org/z/uDFZjz
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D83274
This reverts commit dc13ac02800220a33828ac3da629f382ca7e308d.
Rolling forward + fix typos and unused variables in tests
Differential Revision: https://reviews.llvm.org/D82490
Instead of detecting it automatically (in libc++) and relying on
_LIBCXXABI_NO_EXCEPTIONS being set explicitly (in libc++abi), always
detect whether exceptions are enabled automatically.
This commit also removes support for specifying -D_LIBCPP_NO_EXCEPTIONS
and -D_LIBCXXABI_NO_EXCEPTIONS explicitly -- those should just be inferred
from using -fno-exceptions (or an equivalent flag).
Allowing both -D_FOO_NO_EXCEPTIONS to be provided explicitly and trying
to detect it automatically is just confusing, especially since we did
specify it explicitly when building libc++abi. We should have only one
way to detect whether exceptions are enabled, but it should be robust.
We've decided to move away from that by requiring that libc++ is built
as part of the monorepo a while ago. This commit removes code pertaining
to that unsupported use case and produces a clear error when the user
violates that.
In fact, building outside of the monorepo will still work as long as
LLVM_PATH is pointing to the root of the LLVM project, although that
is not officially supported.
The runtimes build includes libcxx/include/CMakeLists.txt directly instead
of going through the top-level CMake file. This not-very-hygienic inclusion
caused some variables like LIBCXX_BINARY_DIR not to be defined properly,
and the config_site generation logic to fail after landing 53623d4aa710.
This patch works around this issue by defining the missing variables.
However, the proper fix for this would be for the runtimes build to
always go through libc++'s top-level CMakeLists.txt. Doing otherwise
is unsupported.
Before this patch, the __config_site header was only generated when at
least one __config_site macro needed to be defined. This lead to two
different code paths in how libc++ is configured, depending on whether
a __config_site header was generated or not. After this patch, the
__config_site is always generated, but it can be empty in case there
are no macros to define in it.
More context on why this change is important
--------------------------------------------
In addition to being confusing, this double-code-path situation lead to
broken code being checked in undetected in 2405bd689815, which introduced
the LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT CMake setting. Specifically,
the _LIBCPP_HAS_MERGED_TYPEINFO_NAMES_DEFAULT <__config_site> macro was
supposed NOT to be defined unless LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT
was specified explicitly on the CMake command line. Instead, what happened
is that it was defined to 0 if it wasn't specified explicitly and a
<__config_site> header was generated. And defining that macro to 0 had
the important effect of using the non-unique RTTI comparison implementation,
which changes the ABI.
This change in behavior wasn't noticed because the <__config_site> header
is not generated by default. However, the Apple configuration does cause
a <__config_site> header to be generated, which lead to the wrong RTTI
implementation being used, and to https://llvm.org/PR45549. We came close
to an ABI break in the dylib, but were saved due to a downstream-only
change that overrode the decision of the <__config_site> for the purpose
of RTTI comparisons in libc++abi. This is an incredible luck that we should
not rely on ever again.
While the problem itself was fixed with 2464d8135e2a by setting
LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT explicitly in the Apple
CMake cache and then in d0fcdcd28f95 by making the setting less
brittle, the point still is that we should have had a single code
path from the beginning. Unlike most normal libraries, the macros
that configure libc++ are really complex, there's a lot of them and
they control important properties of the C++ runtime. There must be
a single code path for that, and it must be simple and robust.
Differential Revision: https://reviews.llvm.org/D80927
We use the _LIBCPP_ABI_ALTERNATE_STRING_LAYOUT macro for that now instead.
I did leave a check behind to make sure that nobody was still using the old
macro name. I'll remove it a couple of months down the road.
Similar to <concepts>, we need to protect the header and test against
inclusion and being run if concepts aren't supported by the compiler.
Differential Revision: https://reviews.llvm.org/D82171
Summary:
This change adds local 'end' and 'pos' variables for the main loop inmstead of using the ConstructTransaction variables directly.
We observed that not all vector initialization and resize operations got properly vectorized, i.e., (partially) unrolled into XMM stores for floats.
For example, `vector<int32_t> v(n, 1)` gets vectorized, but `vector<float> v(n, 1)`. It looks like the compiler assumes the state is leaked / aliased in the latter case (unclear how/why for float, but not for int32), and because of this fails to see vectorization optimization?
See https://gcc.godbolt.org/z/UWhiie
By using a local `__new_end_` (fixed), and local `__pos` (copied into __tx.__pos_ per iteration), we offer the compiler a clean loop for unrolling.
A demonstration can be seen in the isolated logic in https://gcc.godbolt.org/z/KoCNWv
The com
Reviewers: EricWF, #libc!
Subscribers: libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D82111
Summary:
In the case where `swap` is `noexcept`, we should avoid the extension to provide strong-exception guarantee.
Fixes https://bugs.llvm.org/show_bug.cgi?id=46342
Reviewers: #libc, ldionne
Reviewed By: #libc, ldionne
Subscribers: dexonsmith, mclow.lists, miscco, ldionne, zoecarver, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D81954
The Standard documents the signature of std::advance as
template <class Iter, class Distance>
constexpr void advance(Iter& i, Distance n);
Furthermore, it does not appear to put any restriction on what the type
of Distance should be. While it is understood that it should usually
be std::iterator_traits::difference_type, I couldn't find any wording
that mandates that. Similarly, I couldn't find wording that forces the
distance to be a signed type.
This patch changes std::advance to accept any type in the second argument,
which appears to be what the Standard mandates. We then coerce it to the
iterator's difference type, but that's an implementation detail.
Differential Revision: https://reviews.llvm.org/D81425
The availability markup for bad_optional_access marked it as being added
in MacOS 10.14 and aligned releases, however it appears to have been added
in Mac OS 10.13 and aligned releases.
This effectively implements the resolution of LWG3231, which mandates
that calling year_month_day_last::day() on an invalid year_month_day_last
is unspecified behavior. Before this change, it was undefined behavior.
Differential Revision: https://reviews.llvm.org/D81477
This reverts commit 0c148430cf61, which added an assertion in day().
The Standard doesn't allow day() to crash -- instead it says that the
result is unspecified.
Differential Revision: https://reviews.llvm.org/D70346
All compilers supported by libc++ have rvalues in C++03 mode so, there is no need for this non-rvalue overload.
Differential Revision: https://reviews.llvm.org/D80881
Libc++ provides support for <thread> in C++03 as an extension. Furthermore,
it does not support any compiler that doesn't have rvalue references. It
is hence possible to provide the move constructor and move assignment
operator in C++03.
Like we do for empty std::array, make sure we have assertions in place
for obvious out-of-bounds issues in std::array when the debug mode is
enabled (which isn't by default).
The Standard is currently unimplementable. We have to pick between:
1. Not implementing constexpr support properly in std::array<T, 0>
2. Making std::array<T, 0> non-trivial even when T is trivial
3. Returning nullptr from std::array<T, 0>::begin()
Libc++ initially picked (1). In 77b9abfc8e89, we started implementing constexpr properly, but lost the guarantee of triviality. Since it seems like both (1) and (2) are really important, it seems like (3) is the only viable option for libc++, after all. This is also what other implementations are doing.
This patch moves libc++ from (1) to (3).
It also:
- Improves the test coverage for the various ways of initializing std::array
- Adds tests for the triviality of std::array
- Adds tests for the aggregate-ness of std::array
Reviewed By: #libc, miscco, EricWF, zoecarver
Differential Revision: https://reviews.llvm.org/D80821
When the __config_site header is generated, but LIBCXX_HAS_MERGED_TYPEINFO_NAMES_DEFAULT
wasn't specified, _LIBCPP_HAS_MERGED_TYPEINFO_NAMES_DEFAULT would be defined
to 0, which was the NonUnique RTTI comparison implementation. The intent
was to use the Unique RTTI comparison implementation in that case, which
caused https://llvm.org/PR45549.
Instead, use a proper "switch" to select the RTTI comparison implementation.
Note that 0 can't be used as a value, because that is treated the same
by CMake as a variable that is just not defined.
Differential Revision: https://reviews.llvm.org/D80037
This commit adds missing support for constexpr in std::array under all
standard modes up to and including C++20. It also transforms the <array>
tests to check for constexpr-friendliness under the right standard modes.
Fixes https://llvm.org/PR40124
Fixes rdar://57522096
Supersedes https://reviews.llvm.org/D60666
Differential Revision: https://reviews.llvm.org/D80452
Summary: Update status page and test synopsis. Add synopsis in <cmath>.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D80456
__test_has_construct.
In C++17 some tests started failing after a521532aa16df2c06c91488f2a4e787586f0a611. This fixes those errors by suppressing the deprecation warning when calling `construct` in `__test_has_construct`. This is the same solution as `__has_destroy_test` already uses.
Reviewers: ldionne, #libc!
Subscribers: dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D80481
Summary:
Libcxx only supports compilers with variadics. We can safely remove all "fake" variadic overloads of allocator_traits::construct.
This also provides the correct behavior if anything other than exactly one argument is supplied to allocator_traits::construct in C++03 mode.
Reviewers: ldionne, #libc!
Subscribers: dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D80067
Summary:
As described in the bug report:
The commit a8b9f59e8caf378d56e8bfcecdb22184cdabf42d "Implement feature test macros using a script" added test features macros for libc++. Among others, it added `__cpp_lib_hardware_interference_size`. However, there is nothing like std::hardware_constructive_interference_size nor std::hardware_destructive_interference_size, that should be in header <new>.
* https://bugs.llvm.org/show_bug.cgi?id=41423
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D80431
The two functions don't throw, and the generated code is better when
we explicitly tell the compiler that the functions are noexcept. This
isn't an ABI break because the signatures of the functions stay the
same with or without noexcept.
Fixes https://llvm.org/PR46016
Differential Revision: https://reviews.llvm.org/D80379
Summary:
This LWG issue states that the result of `year_month_day_last::day()` is implementation defined if `ok()` is `false`.
However, from user perspective, calling `day()` in this situation will lead to a (possibly difficult to find) crash.
Hence, I have added an assertion to warn user at least when assertions are enabled.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D70346
Summary: Compilation with -DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY was failing due to missing declarations of functions used in libcxx/include/atomic. The lines this commit affects are the places where those functions are defined, now moved to be always defined.
Reviewers: #libc, ldionne
Reviewed By: #libc, ldionne
Subscribers: miyuki, dexonsmith, ldionne, jfb, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D80372
This change removes both the member function swap and the free function
overload of swap for std::span. While swap is a member and overloaded
for every other container in the standard library [1], it is neither a
member function nor a free function overload for std::span [2].
Thus the corresponding implementation should be removed.
[1] https://eel.is/c++draft/libraryindex#:swap
[2] https://eel.is/c++draft/span.overview
Differential Revision: https://reviews.llvm.org/D69827
Summary: All supported compilers have rvalues and variadics so we can safely remove the overloads of allocator::construct which are only enabled on compilers without rvalues and variadics.
Reviewers: ldionne, #libc!
Subscribers: dexonsmith, libcxx-commits
Tags: #libc
Differential Revision: https://reviews.llvm.org/D80068
