David Spickett 2fa2c2197d
[llvm][docs] MemTagSanitizer is only supported on AArch64 Android (#120545)
```
$ ./bin/clang /tmp/test.c -o /tmp/test.o -target aarch64-linux -march=armv8+memtag -fsanitize=memtag-stack
clang: error: unsupported option '-fsanitize=memtag*' for target 'aarch64-unknown-linux'
```
But this works:
```
$ ./bin/clang /tmp/test.c -o /tmp/test.o --target=aarch64-linux-android -march=armv8+memtag -fsanitize=memtag-stack
```

Due to this check in Clang:

2210da3b82/clang/lib/Driver/ToolChains/CommonArgs.cpp (L1651)

Likely because the required notes and dynamic loader support only exist
for Android.

You can get around this, sort of, by not linking the file. However this
means you have to provide your own way of loading it, so it doesn't
change the statement that this feature is Android only.

https://github.com/llvm/llvm-project/issues/64692 also confirms that the
intent is to only support Android at this time.

And while I'm here, suggest an additive set of flags that can also be
used.
2024-12-20 10:24:23 +00:00
..
2024-05-19 22:09:46 +05:30
2024-07-17 21:57:52 -07:00

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