Files
clang-p2996/llvm/docs
Alexandre Ganea e66500c774 [Support] On Windows 11 and Windows Server 2022, fix an affinity mask issue on large core count machines
Before Windows 11 and Windows Server 2022, only one 'processor group' is assigned by default to a starting process, then the program is responsible for dispatching its own threads on more 'processor groups'. That is what 8404aeb56a was doing, allowing LLVM tools to automatically use all hardware threads in the machine.

After Windows 11 and Windows Server 2022, the OS takes care of that. This has an adverse effect reported in #56618 which is that using `GetProcessAffinityMask()` API in some edge cases seems buggy now. That API is used to detect if an affinity mask was set, and adjust accordingly the available threads for a ThreadPool.

With this patch, on one hand, we let the OS dispatch threads on all 'processor groups', but only for Windows 11 & Windows Server 2022 and after. We retain the old behavior for older OS versions. On the other hand, a workaround was added to mitigate the `GetProcessAffinityMask()` issue described above (see Threading.inc, L226).

Differential Revision: https://reviews.llvm.org/D138747
2023-01-06 17:03:43 -05:00
..
2022-02-20 18:43:30 +00:00
2022-03-01 13:39:51 -08:00
2022-09-11 20:43:57 +02:00
2022-10-10 14:22:25 -04:00
2022-03-21 10:06:27 +01:00

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.rst` 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