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llvm-mirror/docs
Hal Finkel 9c1513447c Simplify and improve scoped-noalias metadata semantics
In the process of fixing the noalias parameter -> metadata conversion process
that will take place during inlining (which will be committed soon, but not
turned on by default), I have come to realize that the semantics provided by
yesterday's commit are not really what we want. Here's why:

void foo(noalias a, noalias b, noalias c, bool x) {
  *q = x ? a : b;
  *c = *q;
}

Generically, we know that *c does not alias with *a and with *b (so there is an
'and' in what we know we're not), and we know that *q might be derived from *a
or from *b (so there is an 'or' in what we know that we are). So we do not want
the semantics currently, where any noalias scope matching any alias.scope
causes a NoAlias return. What we want to know is that the noalias scopes form a
superset of the alias.scope list (meaning that all the things we know we're not
is a superset of all of things the other instruction might be).

Making that change, however, introduces a composibility problem. If we inline
once, adding the noalias metadata, and then inline again adding more, and we
append new scopes onto the noalias and alias.scope lists each time. But, this
means that we could change what was a NoAlias result previously into a MayAlias
result because we appended an additional scope onto one of the alias.scope
lists. So, instead of giving scopes the ability to have parents (which I had
borrowed from the TBAA implementation, but seems increasingly unlikely to be
useful in practice), I've given them domains. The subset/superset condition now
applies within each domain independently, and we only need it to hold in one
domain. Each time we inline, we add the new scopes in a new scope domain, and
everything now composes nicely. In addition, this simplifies the
implementation.

llvm-svn: 213948
2014-07-25 15:50:02 +00:00
..
_static
_templates
_themes/llvm-theme
CommandGuide Fix Sphinx warnings. 2014-07-21 16:39:00 +00:00
HistoricalNotes [typo] An LLVM. 2013-08-16 23:30:19 +00:00
TableGen Fix Sphinx warnings. 2014-07-21 16:39:00 +00:00
tutorial [docs] Clean up some more llvm-gcc stuff 2014-02-19 00:12:34 +00:00
AliasAnalysis.rst Update some AliasAnalysis pass docs for getAdjustedAnalysisPointer. 2014-05-22 19:38:25 +00:00
ARM-BE-bitcastfail.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-bitcastsuccess.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-ld1.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
ARM-BE-ldr.png [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
Atomics.rst IR: add "cmpxchg weak" variant to support permitted failure. 2014-06-13 14:24:07 +00:00
BigEndianNEON.rst Fix typos 2014-05-15 01:52:21 +00:00
BitCodeFormat.rst Revert "[ms-cxxabi] Add a new calling convention that swaps 'this' and 'sret'" 2014-05-09 22:56:42 +00:00
BlockFrequencyTerminology.rst Fix typos 2014-05-15 01:52:21 +00:00
BranchWeightMetadata.rst blockfreq: Document BlockFrequencyInfo terminology 2014-04-11 23:21:07 +00:00
Bugpoint.rst [docs] Fix up some links to the preferred style. 2014-04-08 21:06:22 +00:00
CMake.rst Added LLVM_ENABLE_RTTI and LLVM_ENABLE_EH options that allow RTTI and EH 2014-07-22 15:41:18 +00:00
CMakeLists.txt Added Sphinx documentation generation to CMake build system. 2014-04-18 21:45:25 +00:00
CodeGenerator.rst [docs] Fix a mangled sentence. 2014-07-01 18:22:32 +00:00
CodingStandards.rst Remove the recommendation against using std::function 2014-07-02 00:42:07 +00:00
CommandLine.rst Correct word hyphenations 2013-12-05 05:44:44 +00:00
CompilerWriterInfo.rst Fix some doc and comment typos 2014-04-09 14:47:27 +00:00
conf.py Update the copyright credits -- Happy new year 2014! 2014-01-01 08:27:31 +00:00
DebuggingJITedCode.rst
DeveloperPolicy.rst Document what backwards compatibility we provide for bitcode. 2014-07-23 22:43:22 +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: Clarify how the llvm.eh.* intrinsics are used 2014-03-28 17:08:57 +00:00
ExtendedIntegerResults.txt
ExtendingLLVM.rst Fix documentation on the path to Bitcode reader/writer 2013-06-11 18:09:21 +00:00
Extensions.rst ARM: add VLA extension for WoA Itanium ABI 2014-06-09 20:18:42 +00:00
FAQ.rst remove an old entry whose link is broken anyway 2014-03-02 06:37:03 +00:00
GarbageCollection.rst Fix 'platform-specific' hyphenations 2014-06-30 18:57:16 +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 Drop the udis86 wrapper from llvm::sys 2014-07-17 20:05:29 +00:00
GettingStartedVS.rst Document how to select build configuration with Visual C++ IDE or command line. 2014-06-05 16:42:26 +00:00
GoldPlugin.rst Update the LTO GoldPlugin documentation 2013-12-02 07:15:33 +00:00
HowToAddABuilder.rst
HowToBuildOnARM.rst Adding some info about stability of ARM boards 2013-11-15 08:42:14 +00:00
HowToCrossCompileLLVM.rst [docs] Some typographical fixes. 2013-09-09 19:05:03 +00:00
HowToReleaseLLVM.rst docs: Update relaease documents to include the patch number in the RELEASE tags 2014-07-21 14:28:31 +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 inalloca: *Really* fix the docs 2014-03-27 01:38:48 +00:00
index.rst [ARM64-BE] Add sphinx documentation for the ARM64 NEON implementation. 2014-05-12 15:13:39 +00:00
LangRef.rst Simplify and improve scoped-noalias metadata semantics 2014-07-25 15:50:02 +00:00
Lexicon.rst fixed link 2014-07-14 19:52:36 +00:00
LinkTimeOptimization.rst
linpack-pc.png
LLVMBuild.rst [docs] Fix some links 2014-04-07 22:46:40 +00:00
LLVMBuild.txt
make.bat
Makefile docs: Remove incompatibility with Solaris shell 2013-10-15 08:30:07 +00:00
Makefile.sphinx Revert "Treat warnings in Sphinx as errors. The reasons for doing this are..." 2014-07-22 18:09:17 +00:00
MakefileGuide.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
MarkedUpDisassembly.rst undo test commit (whitespace only) 2014-06-30 08:09:35 +00:00
MCJIT-creation.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJIT-dyld-load.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJIT-engine-builder.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJIT-load-object.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJIT-load.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJIT-resolve-relocations.png Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
MCJITDesignAndImplementation.rst Adding a document to describe the MCJIT execution engine implementation. 2013-08-21 22:15:09 +00:00
NVPTXUsage.rst Fix documentation typos 2013-12-20 00:33:39 +00:00
Packaging.rst
Passes.rst docs: Remove documentation for legacy PGO options 2014-06-04 06:29:38 +00:00
Phabricator.rst Phabricator doc: Explicit the fact that the patch needs to be there before the commit 2014-07-04 09:00:35 +00:00
ProgrammersManual.rst Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
Projects.rst Remove projects/sample. 2014-03-12 22:40:22 +00:00
re_format.7
README.txt [docs] Add a note to docs/README.txt 2014-04-22 21:47:53 +00:00
ReleaseNotes.rst Added release notes for MIPS. 2014-07-23 12:59:26 +00:00
ReleaseProcess.rst Update Release Process doc 2013-06-12 11:35:33 +00:00
SegmentedStacks.rst Move the segmented stack switch to a function attribute 2014-04-10 22:58:43 +00:00
SourceLevelDebugging.rst Debug info: split out complex DIVariable address expressions into a 2014-06-30 17:17:35 +00:00
SphinxQuickstartTemplate.rst
StackMaps.rst Stack map docs. Remove some stray markup. 2014-04-03 07:08:21 +00:00
SystemLibrary.rst
TableGenFundamentals.rst Recover TableGen/LangRef, make it official 2014-04-01 09:51:49 +00:00
TestingGuide.rst Reduce verbiage of lit.local.cfg files 2014-06-09 22:42:55 +00:00
TestSuiteMakefileGuide.rst
Vectorizers.rst Vectorization documentation for loop hint pragmas and Rpass diagnostics. 2014-06-27 18:30:08 +00:00
WritingAnLLVMBackend.rst [docs] Fix some links 2014-04-07 22:46:40 +00:00
WritingAnLLVMPass.rst docs: Remove documentation for legacy PGO options 2014-06-04 06:29:38 +00:00
yaml2obj.rst Object: rename ARMV7 to ARMNT 2014-03-11 03:08:37 +00:00
YamlIO.rst [YAML] Add an optional argument EnumMask to the yaml::IO::bitSetCase(). 2014-05-23 08:07:09 +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`.

Checking links
==============

The reachibility of external links in the documentation can be checked by
running:

    cd docs/
    make -f Makefile.sphinx linkcheck