The flexibility around extern template instantiation declarations in
libc++ result in a very complicated model, especially when support for
slightly different configurations (like the debug mode or assertions
in the dylib) are taken into account. That results in unexpected bugs
like http://llvm.org/PR50534 (and there have been multiple similar
bugs in the past, notably around the debug mode).
This patch gets rid of the _LIBCPP_DISABLE_EXTERN_TEMPLATE knob, which
I don't think is fundamental. Indeed, the motivation for that knob was to
avoid taking a dependency on the library, however that can be done better
by linking against the static library instead. And in fact, some parts of
the headers will always depend on things defined in the library, which
defeats the original goal of _LIBCPP_DISABLE_EXTERN_TEMPLATE.
Differential Revision: https://reviews.llvm.org/D103960
When some headers are not available because we removed features like
localization or threads, the compiler should not try to include these
headers when building modules. To avoid that from happening, add a
requires-declaration that is never satisfied when the configuration
in use doesn't support a header.
rdar://93777687
Differential Revision: https://reviews.llvm.org/D127127
Get rid of the __is_trivially_copy_assignable_unwrapped helper, which
is only used in one place, and use __iter_value_type instead of
iterator_traits<T>::value_type.
Differential Revision: https://reviews.llvm.org/D127230
The debug mode has been broken pretty much ever since it was shipped
because it was possible to enable the debug mode in user code without
actually enabling it in the dylib, leading to ODR violations that
caused various kinds of failures.
This commit makes the debug mode a knob that is configured when
building the library and which can't be changed afterwards. This is
less flexible for users, however it will actually work as intended
and it will allow us, in the future, to add various kinds of checks
that do not assume the same ABI as the normal library. Furthermore,
this will make the debug mode more robust, which means that vendors
might be more tempted to support it properly, which hasn't been the
case with the current debug mode.
This patch shouldn't break any user code, except folks who are building
against a library that doesn't have the debug mode enabled and who try
to enable the debug mode in their code. Such users will get a compile-time
error explaining that this configuration isn't supported anymore.
In the future, we should further increase the granularity of the debug
mode checks so that we can cherry-pick which checks to enable, like we
do for unspecified behavior randomization.
Differential Revision: https://reviews.llvm.org/D122941
After moving the std::to_chars base 10 implementation from the dylib to
the header the integral overloads of std::to_chars are available on all
platforms.
Remove the _LIBCPP_AVAILABILITY_TO_CHARS availability macro and update
the tests.
Depends on D125704
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D125745
This was noticed in the review of D125704. In that commit only the new
table has been adapted. This adapts the existing tables.
Note since libc++'s charconv is backported to C++11 it's not possible to
use inline constexpr variables. The were introduced in C++17.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D126887
In MinGW environments, thanks to slightly different code generation
and linker tricks, it's possible to link against a DLL C++ standard
library without dllimport attributes.
This allows using one single set of headers for linking against
either the DLL or a static library, leaving the decision entirely
up to the linking stage (where it can be switched with options like
-static-libstdc++).
This matches how libstdc++ headers work; there's no dllimport attributes
by default (unless the user has defined _GLIBCXX_DLL when including
headers).
This allows using one single set of headers while linking against
either a DLL or a static library, just like on Unix platforms.
This matches how libc++ has been used in MinGW configurations for
years (by first building the DLL, then configuring a static-only
build and installing on top, overwriting the libc++ config file
with one for static linking) by multiple MinGW toolchains, making
the dllimport-less use the de-facto tested configuration in the wild.
This also allows building all of libc++ in one single CMake
configuration, instead of having to do two separate builds on top of
each other.
(Linking against a DLL without dllimport can break if e.g. templates
use inconsistent visibility attributes - in cases where it still
works when using explicit dllimport; such a case was fixed in
948dd664c3ed30dd853df03cb931436f280bad4a / D99932. With this as the
default configuration, we can catch such issues in CI.)
Differential Revision: https://reviews.llvm.org/D125924
Currently, unary expressions involving valarray will create a temporary.
This leads to dangling references in expressions like `-a * b`, because
`-a` is a temporary and the resulting expression will refer to it. This
patch fixes the problem by creating a lazy expression to perform the unary
operation instead of eagerly creating a temporary valarray. This is
permitted by the Standard, which does not specify the exact type of
most expressions involving valarrays.
This is technically an ABI break, however I believe the actual potential
for breakage is very low.
rdar://90152242
Differential Revision: https://reviews.llvm.org/D125019
Instead of providing two different constructors for iterators that
support the debug mode, provide a single constructor but leave the
container parameter unused when the debug mode is not enabled.
This allows simplifying all the call sites to unconditionally pass
the container, which removes a bunch of duplication in the container's
implementation.
Note that this patch does add some complexity to std::span, however
that is only because std::span has the ability to use raw pointers
as iterators instead of __wrap_iter. In retrospect, I believe it was
a mistake to provide that capability, and so it will be removed in a
future patch, along with the complexity added by this patch.
Differential Revision: https://reviews.llvm.org/D126993
In D122982 I accidentally disabled the memmove optimization. This re-enables it and adds more cases where copy forwards to memmove.
Fixes https://github.com/llvm/llvm-project/issues/33687
Reviewed By: var-const, #libc, ldionne
Spies: pkasting, ayzhao, dcheng, xbolva00, libcxx-commits
Differential Revision: https://reviews.llvm.org/D124328
Small typo fix(es) for struct definition of __optional_storage_base for
a reference type.
Reviewed By: #libc, jloser, philnik
Differential Revision: https://reviews.llvm.org/D126621
This removes the duplicated code from the dylib. Instead the dylib will
call the new functions in the header. Since this code is unneeded it's
removed from the unstable ABI.
Depends on D125704
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D125761
The functions to_chars and from_chars should offer 128-bit support. This
is the first step to implement 128-bit version of to_chars. Before
implementing 128-bit support the current code will be polished.
This moves the code from the dylib to the header in prepartion of
P2291 "Add Constexpr Modifiers to Functions to_chars and from_chars for
Integral Types in <charconv> Header"
Note some more cleanups will be done in follow-up commits
- Remove the _LIBCPP_AVAILABILITY_TO_CHARS from to_chars. With all code
in the header the availablilty macro is no longer needed. This
requires enabling the unit tests for additional platforms.
- The code in the dylib can switch to using the header implementation.
This allows removing the code duplicated in the header and the dylib.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D125704
Formatting a string-literal had an off-by-one issue where the NUL
terminator became part of the formatted output.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D126665
P0798R8 "Monadic operations for std::optional" has been implemented, so
this LWG issue can be adopted.
During review it was discovered another paper bumped the macro. The
part affecting optional of this paper is done, the variant isn't. The
status page is updated to reflect the current state.
Implements
- LWG 3621 Remove feature-test macro __cpp_lib_monadic_optional
Updates status of
- P2231R1 Missing constexpr in std::optional and std::variant
Reviewed By: #libc, philnik, ldionne
Differential Revision: https://reviews.llvm.org/D125813
Those were spotted when a project unintentionally started exporting
these symbols from its ABI just by using the libc++ headers.
Differential Revision: https://reviews.llvm.org/D126496
While looking at D113413 I noticed that __log2i could perhaps be
improved to be both slightly smaller and faster.
projects/libcxx/benchmarks/sort.libcxx.out --benchmark_filter=BM_Sort_uint32_QuickSortAdversary*
suggests this is performance neutral, but it shaves a few bytes off the
benchmark binary, and even more off a Chromium build.
Differential revision: https://reviews.llvm.org/D125958
This commit ensures that we can include all libc++ headers with modules
enabled. It adds a test to ensure that this doesn't regress, which is
necessary because our modules CI job does not build in all Standard modes.
Differential Revision: https://reviews.llvm.org/D125331
Abseil benchmarks suggest that the conditional checks result in faster code (4-5x)
as they are compiled into conditional move instructions (cmov on x86).
Reviewed By: #libc, philnik, Mordante
Spies: pengfei, Mordante, philnik, libcxx-commits
Differential Revision: https://reviews.llvm.org/D125329
This fixes incorrect handling of non-moveable types, adding tests for this case.
See [issue 55346](https://github.com/llvm/llvm-project/issues/55346).
The current implementation is based on is_convertible, which is
[defined](https://timsong-cpp.github.io/cppwp/n4659/meta.rel#5) in terms of
validity of the following function:
```
To test() {
return declval<From>();
}
```
But this doesn't work if To and From are both some non-moveable type, which the
[definition](https://timsong-cpp.github.io/cppwp/n4659/conv#3) of implicit
conversions says should work due to guaranteed copy elision:
```
To to = E; // E has type From
```
It is this latter definition that is used in the
[definition](https://timsong-cpp.github.io/cppwp/n4659/function.objects#func.require-2)
of INVOKE<R>. Make __invokable_r use __is_core_convertible, which
captures the ability to use guaranteed copy elision, making the
definition correct for non-moveable types.
Fixesllvm/llvm-project#55346.
Reviewed By: #libc, philnik, EricWF
Spies: EricWF, jloser, ldionne, philnik, libcxx-commits
Differential Revision: https://reviews.llvm.org/D125300
All compilers that libc++ supports support `push_macro` and `pop_macro`. So let's remove it.
Reviewed By: ldionne, #libc
Spies: libcxx-commits, mgorny
Differential Revision: https://reviews.llvm.org/D126073
`<type_traits>` is quite a large header, so I'll granularize it in a few steps.
Reviewed By: ldionne, #libc
Spies: libcxx-commits, mgorny
Differential Revision: https://reviews.llvm.org/D124755
We should not surface CMake-level options like LIBCXX_ENABLE_FILESYSTEM
to our users, since they don't know what it means. Instead, use a slightly
more general wording.
Also, add an error in <ios> to improve the quality of errors for people
trying to use <iostream> when localization is disabled.
Differential Revision: https://reviews.llvm.org/D125910
We require move semantics in C++03 anyways, so let's enable them for the containers.
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D123802
Use a specialized buffer wrapper to limit the number of insertions in the
buffer. After the limit has been reached the buffer only needs to count
the number of insertions to return the buffer size required to store the
entire output.
Depends on D110498
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D110499
This optimizes the __format_arg_store type to allow a more efficient
storage of the basic_format_args.
It stores the data in two arrays:
- A struct with the tag of the exposition only variant's type and the
offset of the element in the data array. Since this array only depends
on the type information it's calculated at compile time and can be
shared by different instances of this class.
- The arguments converted to the types used in the exposition only
variant of basic_format_arg. This means the packed data can be
directly copied to an element of this variant.
The new code uses rvalue reference arguments in preparation for P2418.
The handle class also has some changes to prepare for P2418. The real
changed for P2418 will be done separately, but these parts make it
easier to implement that paper.
Some parts of existing test code are removed since they were no longer
valid after the changes, but new tests have been added.
Implements parts of:
- P2418 Add support for std::generator-like types to std::format
Completes:
- LWG3473 Normative encouragement in non-normative note
Depends on D121138
Reviewed By: #libc, vitaut, Mordante
Differential Revision: https://reviews.llvm.org/D121514
