llvm-project is home to many sphinx documentation sites, each with
configuration quirks and bespoke extensions.
The sphinx config model makes sharing code somewhat difficult. There
are options like sphinx-multiproject, but some of our docs builds are
out of the source tree while some are done out of the binary tree, so
the multiproject configuration itself would need to be generated. It
also would impose more uniformity around extensions than required.
This change instead creates a python package at utils/docs/llvm_sphinx
and makes it available to all sphinx-build processes via PYTHONPATH.
Each conf.py does not modify its own sys.path because not all builds are
out of the source tree, so there isn't a stable relative path to use to
refer to the utils/docs/ directory.
Type checking via pyright in new package is pinned to being python 3.8
compatible.
The myst slug script from llvm/docs is promoted to be the default,
with a slight edit to targets needed in FlangDriver.md to adapt to the
change.
The ghlinks extension from clang gets lifted to be the first generic
extension, although it is still only used in clang currently. I used it
as an example of a general extension that might be useful for other
projects, but I also intend to add a new generic extension in a future
patch.
As part of the move ghlinks is refactored a bit:
* Rather than have a main function directly to run its tests, those
tests are now run via the command-line entrypoint to the new package,
e.g. `python utils/docs --test` will now replace
`python clang/docs/ghlinks.py --test`. This makes the command-line
more pithy (`python utils/docs/llvm_sphinx/ext/ghlinks --test` is a
bit long), and makes the default behavior when running be to
include utils/docs in the sys.path, so imports can be absolute and
the behavior is as close to the CMake targets as possible.
* The static files that were previously written to a tempdir during
testing are just committed directly in git. The assumption here is
that the original version was taking pains to avoid polluting the
clang/docs directory with test files that would confuse sphinx-build,
and without that limitation the workaround can be removed.
* Some typing-related changes to make it strictly python 3.8 compatible.
Change-Id: Ie16de273f74973f163dbf7fe9d22d80a466d051f
LLVM Documentation
==================
LLVM's documentation is written in reStructuredText, a lightweight
plaintext markup language (file extension `.rst`). While the
reStructuredText documentation should be quite readable in source form, it
is mostly meant to be processed by the Sphinx documentation generation
system to create HTML pages which are hosted on <https://llvm.org/docs/> and
updated after every commit. Manpage output is also supported, see below.
If you instead would like to generate and view the HTML locally, install
Sphinx <http://sphinx-doc.org/> and then do:
cd <build-dir>
cmake -DLLVM_ENABLE_SPHINX=true -DSPHINX_OUTPUT_HTML=true <src-dir>
make -j3 docs-llvm-html
$BROWSER <build-dir>/docs/html/index.html
The mapping between reStructuredText files and generated documentation is
`docs/Foo.rst` <-> `<build-dir>/docs//html/Foo.html` <-> `https://llvm.org/docs/Foo.html`.
If you are interested in writing new documentation, you will want to read
`SphinxQuickstartTemplate.md` which will get you writing documentation
very fast and includes examples of the most important reStructuredText
markup syntax.
Manpage Output
===============
Building the manpages is similar to building the HTML documentation. The
primary difference is to use the `man` makefile target, instead of the
default (which is `html`). Sphinx then produces the man pages in the
directory `<build-dir>/docs/man/`.
cd <build-dir>
cmake -DLLVM_ENABLE_SPHINX=true -DSPHINX_OUTPUT_MAN=true <src-dir>
make -j3 docs-llvm-man
man -l <build-dir>/docs/man/FileCheck.1
The correspondence between .rst files and man pages is
`docs/CommandGuide/Foo.rst` <-> `<build-dir>/docs//man/Foo.1`.
These .rst files are also included during HTML generation so they are also
viewable online (as noted above) at e.g.
`https://llvm.org/docs/CommandGuide/Foo.html`.
Checking links
==============
The reachability of external links in the documentation can be checked by
running:
cd llvm/docs/
sphinx-build -b linkcheck . _build/lintcheck/
# report will be generated in _build/lintcheck/output.txt
Doxygen page Output
==============
Install doxygen <https://www.doxygen.nl/download.html> and dot2tex <https://dot2tex.readthedocs.io/en/latest>.
cd <build-dir>
cmake -DLLVM_ENABLE_DOXYGEN=On <llvm-top-src-dir>
make doxygen-llvm # for LLVM docs
make doxygen-clang # for clang docs
It will generate html in
<build-dir>/docs/doxygen/html # for LLVM docs
<build-dir>/tools/clang/docs/doxygen/html # for clang docs
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