In preparation for running clang-format on the whole code base, we are
also removing mentions of the legacy _LIBCPP_INLINE_VISIBILITY macro in
favor of the newer _LIBCPP_HIDE_FROM_ABI.
We're still leaving the definition of _LIBCPP_INLINE_VISIBILITY to avoid
creating needless breakage in case some older patches are checked-in
with mentions of the old macro. After we branch for LLVM 18, we can do
another pass to clean up remaining uses of the macro that might have
gotten introduced by mistake (if any) and remove the macro itself at the
same time. This is just a minor convenience to smooth out the transition
as much as possible.
See
https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.
Several experimental headers around std::pmr have been slated for
removal for a while now. This patch actually performs the removal and
cleanups from the code base.
This is the first step to implement time zone support in libc++. This
adds the complete tzdb_list class and a minimal tzdb class. The tzdb
class only contains the version, which is used by reload_tzdb.
Next to these classes it contains documentation and build system support
needed for time zone support. The code depends on the IANA Time Zone
Database, which should be available on the platform used or provided by
the libc++ vendors.
The code is labeled as experimental since there will be ABI breaks
during development; the tzdb class needs to have the standard headers.
Implements parts of:
- P0355 Extending <chrono> to Calendars and Time Zones
Addresses:
- LWG3319 Properly reference specification of IANA time zone database
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D154282
This avoids having to add `_LIBCPP_ENUM_VIS`, since that is handled through `type_visibility` and GCC always makes the visibility of enums default. It also fixes and missing `_LIBCPP_EXPORTED_FROM_ABI` on classes when using Clang.
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D153658
Our threading support layer is currently a huge mess. There are too many
configurations with too many confusing names, and none of them are tested
in the usual CI. Here's a list of names related to these configurations:
LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY
_LIBCPP_BUILDING_THREAD_LIBRARY_EXTERNAL
LIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY
_LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL
LIBCXX_HAS_EXTERNAL_THREAD_API
_LIBCPP_HAS_THREAD_API_EXTERNAL
This patch cleans this up by removing the ability to build libc++ with
an "external" threading library for testing purposes, removing 4 out of
6 "names" above. That setting was meant to be used by libc++ developers,
but we don't use it in-tree and it's not part of our CI.
I know the ability to use an external threading API is used by some folks
out-of-tree, and this patch doesn't change that. This only changes the
way they will have to test their external threading support. After this
patch, the intent would be for them to set `-DLIBCXX_HAS_EXTERNAL_THREAD_API=ON`
when building the library, and to provide their usual `<__external_threading>`
header when they are testing the library. This can be done easily now
that we support custom lit configuration files in test suites.
The motivation for this patch is that our threading support layer is
basically unmaintainable -- anything beyond adding a new "backend" in
the slot designed for it requires incredible attention. The complexity
added by this setting just doesn't pull its weigh considering the
available alternatives.
Concretely, this will also allow future patches to clean up
`<__threading_support>` significantly.
Differential Revision: https://reviews.llvm.org/D154466
These macros are always defined identically, so we can simplify the code a bit by merging them.
Reviewed By: ldionne, #libc
Spies: libcxx-commits, krytarowski, smeenai
Differential Revision: https://reviews.llvm.org/D152652
Committing on behalf of davidben. Reviewed as D146190
Patch originally by Jan Dörrie in https://reviews.llvm.org/D120064. I've just updated it to include tests, and update documentation that MSVC ABI is not stable.
In the current implementation both `std::optional` and `std::variant` don't perform the EBO on MSVC's ABI. This is because both classes inherit from multiple empty base classes, which breaks the EBO for MSVC. This patch fixes this issue by applying the `empty_bases` declspec attribute, which is already used to fix a similar issue for `std::tuple`.
See https://reviews.llvm.org/D120064 for discussion on MSVC ABI stability. From the discussion, libc++ doesn't have users that expect a stable ABI on MSVC. The fix is thus applied unconditionally to benefit more users. Documentation has been updated to reflect this.
Fixes https://github.com/llvm/llvm-project/issues/61095.
I am starting to granularize debug-mode checks so they can be controlled
more individually. The goal is for vendors to eventually be able to select
which categories of checks they want embedded in their configuration of
the library with more granularity.
Note that this patch is a bit weird on its own because it does not touch
any of the containers that implement iterator bounds checking through the
__dereferenceable check of the legacy debug mode. However, I added TODOs
to string and vector to change that.
Differential Revision: https://reviews.llvm.org/D138033
The new version is a lot simpler and has less option which were not
used. This uses the CSV files as generated by D133127 as input data.
The current Python script has more features but uses a simple "grep"
making the output less accurate:
- Conditionally included header are always included. This is an issue
since part of our includes are unneeded transitive includes. Based on
the language version they may be omitted. The script however always
includes them.
- Includes in comments are processed as-if they are includes. This is an
issue when comments explain how certain data is generated; of course
there are digraphs which the script omits.
This implementation uses Clang's --trace-includes to generate the includes
per header. This means the input of the generation script always has the
real list of includes.
Libc++ is moving from large monolithic Standard headers to more fine
grained headers. For example, algorithm includes every header in
`__algorithm`. Adding all these detail headers in the graph makes the
output unusable. Instead it only shows the Standard headers. The
transitive includes of the detail headers are parsed and "attributed" to
the Standard header including them. This gives an accurate include graph
without the unneeded clutter. Note that this graph is still big.
This changes fixes the cyclic dependency issue with the previous version
of the tool so the markers and its documentation is removed.
Since the input has no cycles the CI test is removed.
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D134188
This defines a new policy for removal of transitive includes.
The goal of the policy it to make it relatively easy to remove
headers when needed, but avoid breaking developers using and
vendors shipping libc++.
The method used is to guard transitive includes based on the
C++ language version. For the upcoming C++23 we can remove
headers when we want, but for other language versions we try
to keep it to a minimum.
In this code the transitive include of `<chrono>` is removed
since D128577 introduces a header cycle between `<format>`
and `<chrono>`. This cycle is indirectly required by the
Standard. Our cycle dependency tool basically is a grep based
tool, so it needs some hints to ignore cycles. With the input
of our transitive include tests we can create a better tool.
However that's out of the scope of this patch.
Note the flag `_LIBCPP_REMOVE_TRANSITIVE_INCLUDES` remains
unchanged. So users can still opt-out of transitives includes
entirely.
Reviewed By: #libc, ldionne, philnik
Differential Revision: https://reviews.llvm.org/D132284
When -fexperimental-library is passed, libc++ will now pick up the
appropriate __has_feature flag defined by Clang to enable the
experimental library features.
As a fly-by, also update the documentation for the various TSes.
Differential Revision: https://reviews.llvm.org/D130176
This commit re-applies 9ee97ce3b830, which was reverted by 61d417ce
because it broke the LLDB data formatter tests. It also re-applies
6148c79a (the manual GN change associated to it).
Differential Revision: https://reviews.llvm.org/D127444
Instead of marking private symbols with internal_linkage (which leads to
one copy per translation unit -- rather wasteful), use an ABI tag that
gets rev'd with each libc++ version. That way, we know that we can't have
name collisions between implementation-detail functions across libc++
versions, so we'll never violate the ODR. However, within a single program,
each symbol still has a proper name with external linkage, which means
that the linker is free to deduplicate symbols even across TUs.
This actually means that we can guarantee that versions of libc++ can
be mixed within the same program without ever having to take a code size
hit, and without having to manually opt-in -- it should just work out of
the box.
Differential Revision: https://reviews.llvm.org/D127444
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
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
We use `auto` in C++03, so we shouldn't say that we aren't.
Reviewed By: ldionne, #libc
Spies: libcxx-commits
Differential Revision: https://reviews.llvm.org/D126165
As a fly-by fix, enable the complexity-changing assertions in __debug_less
only when the full debug mode is enabled, since debugging level 0 is usually
understood to only contain basic assertions that do not change the complexity
of algorithms.
Differential Revision: https://reviews.llvm.org/D121129
We've stopped doing it in libc++ for a while now because these names
would end up rotting as we move things around and copy/paste stuff.
This cleans up all the existing files so as to stop the spreading
as people copy-paste headers around.
This effort is dedicated to deflake the tests of the users which depend
on the unspecified behavior of algorithms and containers. This also
might help updating the sorting algorithm in libcxx which has the
quadratic worst case in the future or at least create a new one under
flag.
For detailed design, please see the design doc I provide in the patch.
Differential Revision: https://reviews.llvm.org/D96946
Based on https://github.com/NuxiNL/cloudlibc, it appears that the CloudABI
project has been abandoned. This patch removes a bunch of CloudABI specific
logic that had been added to support that platform.
Note that some knobs like LIBCXX_ENABLE_STDIN and LIBCXX_ENABLE_STDOUT
coud be useful in their own right, however those are currently broken.
If we want to re-add such knobs in the future, we can do it like we've
done it for localization & friends so that we can officially support
that configuration.
Differential Revision: https://reviews.llvm.org/D108637
We've been forgetting to add those to most of the <ranges> review.
To avoid forgetting in the future, I added an item in the pre-commit
checklist.
Differential Revision: https://reviews.llvm.org/D106287
This commit finishes moving the <atomic> design documents to the RST
documentation and removes the old documentation. https://libcxx.llvm.org
is already pointing to the new documentation only now, so the removal of
the old documentation is really a NFC.
I went over the old documentation and I don't think we're leaving anything
important behind - I think everything important was mentionned in the RST
documentation anyway.
`__debug_less` ends up running the comparator up-to-twice per comparison,
because whenever `(x < y)` it goes on to verify that `!(y < x)`.
This breaks the strict "Complexity" guarantees of algorithms like
`inplace_merge`, which we test in the test suite. So, just skip the
complexity assertions in debug mode.
Differential Revision: https://reviews.llvm.org/D101677
Adds documentation around libc++'s policy to add noexcept to things that cannot throw but aren't marked as noexcept.
Refs LWG 3518 and D95251.
Differential Revision: https://reviews.llvm.org/D95821
Contrary to the current visibility macro documentation, it appears that
gcc does handle visibility attribute on extern templates correctly, e.g.
https://godbolt.org/g/EejuV7. We need this so that extern template
instantiations of classes not marked _LIBCPP_TEMPLATE_VIS (e.g.
__vector_base_common) are correctly exported with gcc when building with
hidden visibility.
Reviewed By: ldionne
Differential Revision: https://reviews.llvm.org/D35388
* The only exception is that the flag -std=c++2a is still used not to break compatibility with older compilers (clang <= 9, gcc <= 9).
* Bump _LIBCPP_STD_VER for C++20 to 20 and use 21 for the future standard (C++2b).
That's a preparation step to add c++2b support to libc++.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D93383
Currently, vendor-specific availability markup is enabled by default.
This means that even when building against trunk libc++, the headers
will by default prevent you from using some features that were not
released in the dylib on your target platform. This is a source of
frustration since people building libc++ from sources are usually not
trying to use some vendor's released dylib.
For that reason, I've been thinking for a long time that availability
annotations should be off by default, which is the primary change that
this commit enables.
In addition, it reworks the implementation to make it easier for new
vendors to add availability annotations for their platform, and it
refreshes the documentation to reflect the current state of the codebase.
Finally, a CMake configuration option is added to control whether
availability annotations should be turned on for the flavor of libc++
being created. The intent is for vendors like Apple to turn it on, and
for the upstream libc++ to leave it off (the default).
Differential Revision: https://reviews.llvm.org/D90843
This simplifies the workflow for adding new feature-test macros for
contributors. Previously, they would have to move the generated <version>
header from a temporary directory to libc++'s include directory by hand.
This makes the behavior for the <version> header consistent with what's
done for the tests and the documentation.
Instead, use with_system_cxx_lib with various compile-only tests to ensure
that we're getting compile-time errors, as expected. This follows the
lead of ec46cfefe80d5.
The needs of back-deployment testing currently require two different
ways of running the test suite: one based on the deployment target,
and one based on the target triple. Since the triple includes all the
information we need, it's better to have just one way of doing things.
Furthermore, `--param platform=XXX` is also supersedded by using the
target triple. Previously, this parameter would serve the purpose of
controling XFAILs for availability markup errors, however it is possible
to achieve the same thing by using with_system_cxx_lib only and using
.verify.cpp tests instead, as explained in the documentation changes.
The motivation for this change is twofold:
1. This part of the Lit config has always been really confusing and
complicated, and it has been a source of bugs in the past. I have
simplified it iteratively in the past, but the complexity is still
there.
2. The deployment-target detection started failing in weird ways in
recent Clangs, breaking our CI. Instead of band-aid patching the
issue, I decided to remove the complexity altogether by using target
triples even on Apple platforms.
A follow-up to this commit will bring the test suite in line with
the recommended way of handling availability markup tests.
This reverts commit dc13ac02800220a33828ac3da629f382ca7e308d.
Rolling forward + fix typos and unused variables in tests
Differential Revision: https://reviews.llvm.org/D82490
This is already handled by setting cxx_runtime_root instead -- I don't
see a reason to have two ways of setting the runtime path of the library
we're running against.
Instead of spamming a bunch of available features that are not actually
used anywhere, only set those that are actually used in the test suite.
In the future, this should probably be based on the target triple only,
with the ability to have wildcards in the triple.
