llvm-6502/docs
Rafael Espindola 1f21e0dd0d Remove the linker_private and linker_private_weak linkages.
These linkages were introduced some time ago, but it was never very
clear what exactly their semantics were or what they should be used
for. Some investigation found these uses:

* utf-16 strings in clang.
* non-unnamed_addr strings produced by the sanitizers.

It turns out they were just working around a more fundamental problem.
For some sections a MachO linker needs a symbol in order to split the
section into atoms, and llvm had no idea that was the case. I fixed
that in r201700 and it is now safe to use the private linkage. When
the object ends up in a section that requires symbols, llvm will use a
'l' prefix instead of a 'L' prefix and things just work.

With that, these linkages were already dead, but there was a potential
future user in the objc metadata information. I am still looking at
CGObjcMac.cpp, but at this point I am convinced that linker_private
and linker_private_weak are not what they need.

The objc uses are currently split in

* Regular symbols (no '\01' prefix). LLVM already directly provides
whatever semantics they need.
* Uses of a private name (start with "\01L" or "\01l") and private
linkage. We can drop the "\01L" and "\01l" prefixes as soon as llvm
agrees with clang on L being ok or not for a given section. I have two
patches in code review for this.
* Uses of private name and weak linkage.

The last case is the one that one could think would fit one of these
linkages. That is not the case. The semantics are

* the linker will merge these symbol by *name*.
* the linker will hide them in the final DSO.

Given that the merging is done by name, any of the private (or
internal) linkages would be a bad match. They allow llvm to rename the
symbols, and that is really not what we want. From the llvm point of
view, these objects should really be (linkonce|weak)(_odr)?.

For now, just keeping the "\01l" prefix is probably the best for these
symbols. If we one day want to have a more direct support in llvm,
IMHO what we should add is not a linkage, it is just a hidden_symbol
attribute. It would be applicable to multiple linkages. For example,
on weak it would produce the current behavior we have for objc
metadata. On internal, it would be equivalent to private (and we
should then remove private).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203866 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-13 23:18:37 +00:00
..
_static
_templates
_themes/llvm-theme
CommandGuide [docs] Clean up some more llvm-gcc stuff 2014-02-19 00:12:34 +00:00
HistoricalNotes
TableGen [docs] TableGen easter egg: Multiline string literals 2014-02-09 02:43:50 +00:00
tutorial [docs] Clean up some more llvm-gcc stuff 2014-02-19 00:12:34 +00:00
AliasAnalysis.rst
Atomics.rst
BitCodeFormat.rst Remove the linker_private and linker_private_weak linkages. 2014-03-13 23:18:37 +00:00
BranchWeightMetadata.rst
Bugpoint.rst
CMake.rst [docs] Teach CMake docs build how to generate Qt Creator help/documentation files. 2014-03-07 19:19:28 +00:00
CMakeLists.txt [docs] Teach CMake docs build how to generate Qt Creator help/documentation files. 2014-03-07 19:19:28 +00:00
CodeGenerator.rst [ms-cxxabi] Add a new calling convention that swaps 'this' and 'sret' 2014-01-31 17:41:22 +00:00
CodingStandards.rst C++11: Remove const from in auto guidelines 2014-03-07 18:06:15 +00:00
CommandLine.rst
CompilerWriterInfo.rst Update the links to the SPARC information. 2013-12-19 20:54:33 +00:00
conf.py Update the copyright credits -- Happy new year 2014! 2014-01-01 08:27:31 +00:00
DebuggingJITedCode.rst
DeveloperPolicy.rst [docs] Clean up some more llvm-gcc stuff 2014-02-19 00:12:34 +00:00
doxygen.cfg.in [docs] Teach CMake docs build how to generate Qt Creator help/documentation files. 2014-03-07 19:19:28 +00:00
doxygen.css
doxygen.footer Update the copyright credits -- Happy new year 2014! 2014-01-01 08:27:31 +00:00
doxygen.header
doxygen.intro
Dummy.html
ExceptionHandling.rst Exception handling docs: Fix a typo 2014-02-27 06:54:04 +00:00
ExtendedIntegerResults.txt
ExtendingLLVM.rst
Extensions.rst Fix typo 2014-02-15 06:02:36 +00:00
FAQ.rst remove an old entry whose link is broken anyway 2014-03-02 06:37:03 +00:00
GarbageCollection.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
gcc-loops.png
GetElementPtr.rst [docs] Clean up some more llvm-gcc stuff 2014-02-19 00:12:34 +00:00
GettingStarted.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
GettingStartedVS.rst Updating the getting started guide for Visual Studio a smidge. 2014-01-23 20:46:44 +00:00
GoldPlugin.rst
HowToAddABuilder.rst
HowToBuildOnARM.rst
HowToCrossCompileLLVM.rst
HowToReleaseLLVM.rst [docs] Fix some Sphinx warnings. 2014-03-02 00:21:42 +00:00
HowToSetUpLLVMStyleRTTI.rst [C++11] Replace LLVM-style type traits with C++11 standard ones. 2014-03-07 14:42:25 +00:00
HowToSubmitABug.rst [docs] Nuke some references to llvm-gcc 2014-02-18 23:56:43 +00:00
HowToUseAttributes.rst
HowToUseInstrMappings.rst
InAlloca.rst Change inalloca rules to make it only apply to the last parameter 2014-01-16 22:59:24 +00:00
index.rst [docs] Fix some Sphinx warnings. 2014-03-02 00:21:42 +00:00
LangRef.rst Remove the linker_private and linker_private_weak linkages. 2014-03-13 23:18:37 +00:00
Lexicon.rst
LinkTimeOptimization.rst
linpack-pc.png
LLVMBuild.rst Fix documentation typos 2013-12-20 00:33:39 +00:00
LLVMBuild.txt
make.bat
Makefile
Makefile.sphinx
MakefileGuide.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
MarkedUpDisassembly.rst
MCJIT-creation.png
MCJIT-dyld-load.png
MCJIT-engine-builder.png
MCJIT-load-object.png
MCJIT-load.png
MCJIT-resolve-relocations.png
MCJITDesignAndImplementation.rst
NVPTXUsage.rst Fix documentation typos 2013-12-20 00:33:39 +00:00
Packaging.rst
Passes.rst
Phabricator.rst Docs: remove paragraph about manual account creation. 2014-03-10 19:24:30 +00:00
ProgrammersManual.rst "Mac OS/X" -> "Mac OS X" spelling fixes for llvm. 2014-03-07 18:08:54 +00:00
Projects.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
re_format.7
README.txt
ReleaseNotes.rst Now that it is possible, use the mangler in IRObjectFile. 2014-02-28 02:17:23 +00:00
ReleaseProcess.rst
SegmentedStacks.rst
SourceLevelDebugging.rst Add DWARF discriminator support to DILexicalBlocks. 2014-03-03 18:53:17 +00:00
SphinxQuickstartTemplate.rst
StackMaps.rst [Stackmaps] Record the stack size of each function that contains a stackmap/patchpoint intrinsic. 2014-01-30 18:58:27 +00:00
SystemLibrary.rst
TableGenFundamentals.rst [docs] [tblgen] clarify that code fragments are just string literals 2014-02-09 02:54:26 +00:00
TestingGuide.rst Cleanup docs about lit substitutions 2014-02-15 08:35:56 +00:00
TestSuiteMakefileGuide.rst
Vectorizers.rst Fix whitespace in vectorizer example 2014-03-12 23:58:07 +00:00
WritingAnLLVMBackend.rst Add a RequireStructuredCFG Field to TargetMachine. 2013-12-07 01:49:19 +00:00
WritingAnLLVMPass.rst
yaml2obj.rst Object: rename ARMV7 to ARMNT 2014-03-11 03:08:37 +00:00
YamlIO.rst Fix documentation typos 2013-12-20 00:33:39 +00:00

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 <http://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 docs/
    make -f Makefile.sphinx
    $BROWSER _build/html/index.html

The mapping between reStructuredText files and generated documentation is
`docs/Foo.rst` <-> `_build/html/Foo.html` <-> `http://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/man/`.

    cd docs/
    make -f Makefile.sphinx man
    man -l _build/man/FileCheck.1

The correspondence between .rst files and man pages is
`docs/CommandGuide/Foo.rst` <-> `_build/man/Foo.1`.
These .rst files are also included during HTML generation so they are also
viewable online (as noted above) at e.g.
`http://llvm.org/docs/CommandGuide/Foo.html`.