Add a warning to the `Building Libcxx` documentation about the
limitations of the utility of `--fresh` at the top level.
Signed-off-by: Will Hawkins <hawkinsw@obs.cr>
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
The vendors of the MSVC STL, libstdc++ and libc++ have agreed [1] to
make the C++23 modules std and std.compat available in C++20. This
provides the std module; libc++ has not implemented the std.compat
module yet.
[1] https://github.com/microsoft/STL/issues/3945
Depends on D158357
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D158358
This adds more information regarding the libc++ coding style and
reference that are useful when working on a standard library
implementation.
This information is based on review comments and tips I give to new
contributors an information I wish I'd know when I started working on
libc++.
Depends on D156051
Reviewed By: #libc, jloser, var-const, ldionne
Differential Revision: https://reviews.llvm.org/D156052
Note that there is a Differential revision for the stride ranges
view implementation and the names of the people who are developing
it.
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D158446
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
The --mapping_file switch was missing; the example would have been
rejected.
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D157785
The link syntax was missing a trailing underscore, and there was an
extraneous backtick on the reference to IWYU's libcxx.imp.
Reviewed By: #libc, philnik
Spies: Mordante, libcxx-commits
Differential Revision: https://reviews.llvm.org/D157784
In the event the internal function __init is called with an empty string the code will take unnecessary extra steps, in addition, the code generated might be overall greater because, to my understanding, when initializing a string with an empty `const char*` "" (like in this case), the compiler might be unable to deduce the string is indeed empty at compile time and more code is generated.
The goal of this patch is to make a new internal function that will accept just an error code skipping the empty string argument. It should skip the unnecessary steps and in the event `if (ec)` is `false`, it will return an empty string using the correct ctor, avoiding any extra code generation issues.
After the conversation about this patch matured in the libcxx channel on the LLVM Discord server, the patch was analyzed quickly with "Compiler Explorer" and other tools and it was discovered that it does indeed reduce the amount of code generated when using the latest stable clang version (16) which in turn produces faster code.
This patch targets LLVM 18 as it will break the ABI by addressing https://github.com/llvm/llvm-project/issues/63985
Benchmark tests run on other machines as well show in the best case, that the new version without the extra string as an argument performs 10 times faster.
On the buildkite CI run it shows the new code takes less CPU time as well.
In conclusion, the new code should also just appear cleaner because there are fewer checks to do when there is no message.
Reviewed By: #libc, philnik
Spies: emaste, nemanjai, philnik, libcxx-commits
Differential Revision: https://reviews.llvm.org/D155820
I need to use header_information.py in a generator script that isn't for tests in an upcoming change. Move it up a level so that it's in utils/libcxx instead of utils/libcxx/tests.
Differential Revision: https://reviews.llvm.org/D157639
This has been deprecated and should be removed now.
Reviewed By: #libc, Mordante
Spies: Mordante, libcxx-commits
Differential Revision: https://reviews.llvm.org/D157058
This implements P0009 std::mdspan ((https://wg21.link/p0009)),
a multidimensional span with customization points for
layouts and data access.
Co-authored-by: Damien L-G <dalg24@gmail.com>
Differential Revision: https://reviews.llvm.org/154367
Existing notes were not fully correct and were missing a detail:
- `std::vector` was annotated long time ago,
- `std::deque` annotations are new,
- now container annotations were extended to all allocators (support in ASan API exists since LLVM16).
Reviewed By: philnik, #libc
Differential Revision: https://reviews.llvm.org/D156162
Implements parts of
- P2093R14 Formatted output
- P2539R4 Should the output of std::print to a terminal be
synchronized with the underlying stream?
Depends on D150044
Reviewed By: #libc, ldionne
Differential Revision: https://reviews.llvm.org/D155262
The headers that include_next compiler and OS headers need to be in different top level modules in order to avoid module cycles. e.g. libc++'s stdlib.h will #include_next stdlib.h from the compiler and then the C library. Either of those are likely to include stddef.h, which will come back up to the libc++ module map and create a module cycle. Putting stdlib.h and stddef.h (and the rest of the C standard library headers) in top level modules resolves this by letting the order go cxx_stdlib_h -> os_stdlib_h -> cxx_stddef_h -> os_stddef_h.
All of those headers' dependencies then need to be moved into top level modules themselves to avoid module cycles between the new top level level cstd modules. This starts to get complicated, as the libc++ C headers, by standard, have to include many of the C++ headers, which include the private detail headers, which are intertwined. e.g. some `__algorithm` headers include `__memory` headers and vice versa.
Make top level modules for all of the libc++ headers to easily guarantee that the modules aren't cyclic.
Add enough module exports to fix `check-cxx` and `run-buildbot generic-modules`.
`__stop_token/intrusive_shared_ptr.h` uses `__atomic/atomic.h` but has no include path to it. Add that include.
`math.h` absorbs `bits/atomic_wide_counter.h` on some platforms that don't have modules, work around that by including `math.h` in `__threading_support`.
<mutex> doesn't actually require threads, there are a few pieces like once_flag that work without threads. Remove the requirement from its module.
AIX is no longer able to support modular builds.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D144322
