mirror of
https://github.com/capstone-engine/llvm-capstone.git
synced 2024-12-23 16:06:24 +00:00
3c84aca9b3
It's hard to imagine someone using a recent version of libc++ with a roughly 3 years old Clang. Since we're not testing libc++ with Clang 3.5 anyway, claiming support for it is somewhat of a lie. Note that we don't test Clang 4 either, however I have no reason to bump the requirement beyond Clang 4 at the moment, whereas removing Clang 3.5 allows simplifying the test suite. Differential Revision: https://reviews.llvm.org/D76618
194 lines
6.7 KiB
ReStructuredText
194 lines
6.7 KiB
ReStructuredText
.. _index:
|
|
|
|
=============================
|
|
"libc++" C++ Standard Library
|
|
=============================
|
|
|
|
Overview
|
|
========
|
|
|
|
libc++ is a new implementation of the C++ standard library, targeting C++11 and
|
|
above.
|
|
|
|
* Features and Goals
|
|
|
|
* Correctness as defined by the C++11 standard.
|
|
* Fast execution.
|
|
* Minimal memory use.
|
|
* Fast compile times.
|
|
* ABI compatibility with gcc's libstdc++ for some low-level features
|
|
such as exception objects, rtti and memory allocation.
|
|
* Extensive unit tests.
|
|
|
|
* Design and Implementation:
|
|
|
|
* Extensive unit tests
|
|
* Internal linker model can be dumped/read to textual format
|
|
* Additional linking features can be plugged in as "passes"
|
|
* OS specific and CPU specific code factored out
|
|
|
|
|
|
Getting Started with libc++
|
|
---------------------------
|
|
|
|
.. toctree::
|
|
:maxdepth: 2
|
|
|
|
ReleaseNotes
|
|
UsingLibcxx
|
|
BuildingLibcxx
|
|
TestingLibcxx
|
|
|
|
|
|
.. toctree::
|
|
:hidden:
|
|
|
|
FeatureTestMacroTable
|
|
|
|
Current Status
|
|
--------------
|
|
|
|
After its initial introduction, many people have asked "why start a new
|
|
library instead of contributing to an existing library?" (like Apache's
|
|
libstdcxx, GNU's libstdc++, STLport, etc). There are many contributing
|
|
reasons, but some of the major ones are:
|
|
|
|
* From years of experience (including having implemented the standard
|
|
library before), we've learned many things about implementing
|
|
the standard containers which require ABI breakage and fundamental changes
|
|
to how they are implemented. For example, it is generally accepted that
|
|
building std::string using the "short string optimization" instead of
|
|
using Copy On Write (COW) is a superior approach for multicore
|
|
machines (particularly in C++11, which has rvalue references). Breaking
|
|
ABI compatibility with old versions of the library was
|
|
determined to be critical to achieving the performance goals of
|
|
libc++.
|
|
|
|
* Mainline libstdc++ has switched to GPL3, a license which the developers
|
|
of libc++ cannot use. libstdc++ 4.2 (the last GPL2 version) could be
|
|
independently extended to support C++11, but this would be a fork of the
|
|
codebase (which is often seen as worse for a project than starting a new
|
|
independent one). Another problem with libstdc++ is that it is tightly
|
|
integrated with G++ development, tending to be tied fairly closely to the
|
|
matching version of G++.
|
|
|
|
* STLport and the Apache libstdcxx library are two other popular
|
|
candidates, but both lack C++11 support. Our experience (and the
|
|
experience of libstdc++ developers) is that adding support for C++11 (in
|
|
particular rvalue references and move-only types) requires changes to
|
|
almost every class and function, essentially amounting to a rewrite.
|
|
Faced with a rewrite, we decided to start from scratch and evaluate every
|
|
design decision from first principles based on experience.
|
|
Further, both projects are apparently abandoned: STLport 5.2.1 was
|
|
released in Oct'08, and STDCXX 4.2.1 in May'08.
|
|
|
|
Platform and Compiler Support
|
|
-----------------------------
|
|
|
|
libc++ is known to work on the following platforms, using gcc and
|
|
clang.
|
|
Note that functionality provided by ``<atomic>`` is only functional with clang
|
|
and GCC.
|
|
|
|
============ ==================== ============ ========================
|
|
OS Arch Compilers ABI Library
|
|
============ ==================== ============ ========================
|
|
macOS i386, x86_64 Clang, GCC libc++abi
|
|
FreeBSD 10+ i386, x86_64, ARM Clang, GCC libcxxrt, libc++abi
|
|
Linux i386, x86_64 Clang, GCC libc++abi
|
|
============ ==================== ============ ========================
|
|
|
|
The following minimum compiler versions are strongly recommended.
|
|
|
|
* Clang 4.0 and above
|
|
* GCC 5.0 and above.
|
|
|
|
The C++03 dialect is only supported for Clang compilers.
|
|
|
|
C++ Dialect Support
|
|
---------------------
|
|
|
|
* C++11 - Complete
|
|
* `C++14 - Complete <http://libcxx.llvm.org/cxx1y_status.html>`__
|
|
* `C++17 - In Progress <http://libcxx.llvm.org/cxx1z_status.html>`__
|
|
* `Post C++14 Technical Specifications - In Progress <http://libcxx.llvm.org/ts1z_status.html>`__
|
|
* :ref:`C++ Feature Test Macro Status <feature-status>`
|
|
|
|
Notes and Known Issues
|
|
----------------------
|
|
|
|
This list contains known issues with libc++
|
|
|
|
* Building libc++ with ``-fno-rtti`` is not supported. However
|
|
linking against it with ``-fno-rtti`` is supported.
|
|
|
|
|
|
A full list of currently open libc++ bugs can be `found here`__.
|
|
|
|
.. __: https://bugs.llvm.org/buglist.cgi?component=All%20Bugs&product=libc%2B%2B&query_format=advanced&resolution=---&order=changeddate%20DESC%2Cassigned_to%20DESC%2Cbug_status%2Cpriority%2Cbug_id&list_id=74184
|
|
|
|
Design Documents
|
|
----------------
|
|
|
|
.. toctree::
|
|
:maxdepth: 1
|
|
|
|
DesignDocs/AvailabilityMarkup
|
|
DesignDocs/DebugMode
|
|
DesignDocs/CapturingConfigInfo
|
|
DesignDocs/ABIVersioning
|
|
DesignDocs/ExperimentalFeatures
|
|
DesignDocs/VisibilityMacros
|
|
DesignDocs/ThreadingSupportAPI
|
|
DesignDocs/FileTimeType
|
|
DesignDocs/FeatureTestMacros
|
|
DesignDocs/ExtendedCXX03Support
|
|
|
|
* `<atomic> design <http://libcxx.llvm.org/atomic_design.html>`_
|
|
* `<type_traits> design <http://libcxx.llvm.org/type_traits_design.html>`_
|
|
* `Notes by Marshall Clow`__
|
|
|
|
.. __: https://cplusplusmusings.wordpress.com/2012/07/05/clang-and-standard-libraries-on-mac-os-x/
|
|
|
|
Build Bots and Test Coverage
|
|
----------------------------
|
|
|
|
* `LLVM Buildbot Builders <http://lab.llvm.org:8011/console>`_
|
|
* `Apple Jenkins Builders <http://lab.llvm.org:8080/green/view/Libcxx/>`_
|
|
* `Windows Appveyor Builders <https://ci.appveyor.com/project/llvm-mirror/libcxx>`_
|
|
* `Code Coverage Results <http://efcs.ca/libcxx-coverage>`_
|
|
|
|
Getting Involved
|
|
================
|
|
|
|
First please review our `Developer's Policy <https://llvm.org/docs/DeveloperPolicy.html>`__
|
|
and `Getting started with LLVM <https://llvm.org/docs/GettingStarted.html>`__.
|
|
|
|
**Bug Reports**
|
|
|
|
If you think you've found a bug in libc++, please report it using
|
|
the `LLVM Bugzilla`_. If you're not sure, you
|
|
can post a message to the `libcxx-dev mailing list`_ or on IRC.
|
|
|
|
**Patches**
|
|
|
|
If you want to contribute a patch to libc++, the best place for that is
|
|
`Phabricator <https://llvm.org/docs/Phabricator.html>`_. Please add `libcxx-commits` as a subscriber.
|
|
Also make sure you are subscribed to the `libcxx-commits mailing list <http://lists.llvm.org/mailman/listinfo/libcxx-commits>`_.
|
|
|
|
**Discussion and Questions**
|
|
|
|
Send discussions and questions to the
|
|
`libcxx-dev mailing list <http://lists.llvm.org/mailman/listinfo/libcxx-dev>`_.
|
|
|
|
|
|
|
|
Quick Links
|
|
===========
|
|
* `LLVM Homepage <https://llvm.org/>`_
|
|
* `libc++abi Homepage <http://libcxxabi.llvm.org/>`_
|
|
* `LLVM Bugzilla <https://bugs.llvm.org/>`_
|
|
* `libcxx-commits Mailing List`_
|
|
* `libcxx-dev Mailing List`_
|
|
* `Browse libc++ Sources <https://github.com/llvm/llvm-project/tree/master/libcxx/>`_
|