Files
clang-p2996/llvm/docs
David Spickett ca715de4bc [llvm][DebugInfo] Add DW_AT_type to DW_TAG_enumeration_type in non-strict DWARF v2 mode (#98335)
During testing of https://github.com/llvm/llvm-project/pull/96202 we
found that when clang set to DWARF v2 was used to build the test file,
lldb could not tell that the unsigned enum type was in fact unsigned. So
it defaulted to signed and printed the wrong value.

The reason for this is that DWARFv2 does not include DW_AT_type in
DW_TAG_enumeration_type. This was added in DWARF v3:
"The enumeration type entry may also have a DW_AT_type attribute which
refers to the underlying data type used to implement the enumeration.

In C or C++, the underlying type will be the appropriate integral type
determined by the compiler from the properties of the enumeration
literal values."

I noticed that gcc does emit this attribute for DWARF v2 but not when
strict DWARF is requested (more details in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=16063#c7).

This patch changes to clang to do the same. This will improve the
experience of anyone using tools that can understand the attribute but
for whatever reason are stuck building binaries containing v2 only.

You can see a current clang/gcc comparison here:
https://godbolt.org/z/eG9Kc9WGf

https://reviews.llvm.org/D42734 added the original code that emitted
this for >= v3 only.
2024-07-12 09:42:30 +01:00
..
2023-12-17 15:36:44 -08:00
2024-05-19 22:09:46 +05:30
2024-01-09 11:06:33 +08:00

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