[libcxx] Add new Sphinx documentation
Summary:
This patch adds Sphinx based documentation to libc++. The goal is to make it easier to write documentation for libc++ since writing new documentation in HTML is cumbersome. This patch rewrites the main page for libc++ along with the instructions for using, building and testing libc++.
The built documentation can be found and reviewed here: http://efcs.ca/libcxx-docs
In order to build the sphinx documentation you need to specify the cmake options `-DLLVM_ENABLE_SPHINX=ON -DLIBCXX_INCLUDE_DOCS=ON`. This will add the makefile rule `docs-libcxx-html`.
Reviewers: chandlerc, mclow.lists, danalbert, jroelofs
Subscribers: silvas, cfe-commits
Differential Revision: http://reviews.llvm.org/D12129
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@245788 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/index.rst b/docs/index.rst
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+.. _index:
+
+=============================
+"libc++" C++ Standard Library
+=============================
+
+Overview
+========
+
+libc++ is a new implementation of the C++ standard library, targeting C++11.
+
+* 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
+
+ UsingLibcxx
+ BuildingLibcxx
+ TestingLibcxx
+
+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-4.2 and
+clang (lack of C++11 language support disables some functionality).
+Note that functionality provided by ``<atomic>`` is only functional with clang
+and GCC.
+
+============ ==================== ============ ========================
+OS Arch Compilers ABI Library
+============ ==================== ============ ========================
+Mac OS X 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 3.5 and above
+* GCC 4.7 and above.
+
+Anything older *may* work.
+
+C++ Dialect Support
+---------------------
+
+* C++11 - Complete
+* `C++14 - Complete <cxx14 status_>`__
+* `C++1z - In Progress <cxx1z status_>`__
+* `Post C++14 Technical Specifications - In Progress <ts status_>`__
+
+.. _cxx14 status: http://libcxx.llvm.org/cxx1y_status.html
+.. _cxx1z status: http://libcxx.llvm.org/cxx1z_status.html
+.. _ts status: http://libcxx.llvm.org/ts1z_status.html
+
+
+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.
+* On OS X v10.8 and older the CMake option ``-DLIBCXX_LIBCPPABI_VERSION=""``
+ must be used during configuration.
+
+
+A full list of currently open libc++ bugs can be `found here <libcxx bug list_>`__.
+
+.. _libcxx bug list: https://llvm.org/bugs/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
+----------------
+
+* `<atomic> design <http://libcxx.llvm.org/atomic_design.html>`_
+* `<type_traits> design <http://libcxx.llvm.org/type_traits_design.html>`_
+* `Status of debug mode <http://libcxx.llvm.org/debug_mode.html>`_
+* `Notes by Marshall Clow <clow notes_>`__
+
+.. _clow notes: https://cplusplusmusings.wordpress.com/2012/07/05/clang-and-standard-libraries-on-mac-os-x/
+
+Getting Involved
+================
+
+First please review our `Developer's Policy <http://llvm.org/docs/DeveloperPolicy.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 `cfe-dev`_. mailing list or on IRC.
+Please include "libc++" in your subject.
+
+**Patches**
+
+If you want to contribute a patch to libc++, the best place for that is
+`Phabricator <phab doc_>`__. Please include [libcxx] in the subject and
+add `cfe-commits` as a subscriber.
+
+**Discussion and Questions**
+
+Send discussions and questions to the `clang mailing list <cfe-dev_>`__.
+Please include [libcxx] in the subject.
+
+.. _phab doc: http://llvm.org/docs/Phabricator.html
+.. _cfe-dev: http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev
+
+Links
+=====
+
+* `Getting started with LLVM <http://llvm.org/docs/GettingStarted.html>`_
+* `libc++abi Homepage <libc++abi_>`__
+
+.. _`libc++abi`: http://libcxxabi.llvm.org/
