When packaging LLVM we've seen arbitrary tests fail.
It happened sporadically and most of the times the test
do work if they are run a second time on the next day.
The tests themselves were always different and we didn't
know ahead of time which ones we wanted to re-run.
That's we filter-out a lot of `libomp` and `libarcher` tests [1].
This change allows us to set
`LIT_OPTS="--max-retries-per-test=12"`
when running any "check-XXX" build target. Then any lit test
will at most be re-run 12 times, unless there's an `ALLOW_RETRIES:`
in one of the test scripts that's specifying a different value
than `12`. `12` is just an example here, any positive integer
will work.
Please note, that this only adds the possibility to re-run
lit tests. It does not actually do it until the caller specifies
`--max-retries-per-test=<POSITIVE_INT>` either on a call to `lit` or
in `LIT_OPTS`.
Also note, that one can still use `ALLOW_RETRIES:` in test scripts
and it will always rule over `--max-retries-per-test`. When
`--max-retries-per-test` is set too low, but the
`config.test_retry_attempts`
is high enough, it works as well.
Any option in the list below overrules its predecessor:
* `--max-retries-per-test`
* `config.test_retry_attempts`
* `ALLOW_RETRIES` keyword
From the above options to re-run tests, `--max-retries-per-test` is the
only one that doesn't require a change in the test scripts or the test
config.
[1]:
https://src.fedoraproject.org/rpms/llvm/blob/rawhide/f/llvm.spec#_2326
Downstream PR to make use of the `--max-retries-per-test` option:
https://src.fedoraproject.org/rpms/llvm/pull-request/434
Downstream ticket: https://issues.redhat.com/browse/LLVM-145
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
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