llvm/docs
Gor Nishanov 2d33745172 [coroutines] Add handling for unwind coro.ends
Summary:
The purpose of coro.end intrinsic is to allow frontends to mark the cleanup and
other code that is only relevant during the initial invocation of the coroutine
and should not be present in resume and destroy parts.

In landing pads coro.end is replaced with an appropriate instruction to unwind to
caller. The handling of coro.end differs depending on whether the target is
using landingpad or WinEH exception model.

For landingpad based exception model, it is expected that frontend uses the
`coro.end`_ intrinsic as follows:

```
    ehcleanup:
      %InResumePart = call i1 @llvm.coro.end(i8* null, i1 true)
      br i1 %InResumePart, label %eh.resume, label %cleanup.cont

    cleanup.cont:
      ; rest of the cleanup

    eh.resume:
      %exn = load i8*, i8** %exn.slot, align 8
      %sel = load i32, i32* %ehselector.slot, align 4
      %lpad.val = insertvalue { i8*, i32 } undef, i8* %exn, 0
      %lpad.val29 = insertvalue { i8*, i32 } %lpad.val, i32 %sel, 1
      resume { i8*, i32 } %lpad.val29

```
The `CoroSpit` pass replaces `coro.end` with ``True`` in the resume functions,
thus leading to immediate unwind to the caller, whereas in start function it
is replaced with ``False``, thus allowing to proceed to the rest of the cleanup
code that is only needed during initial invocation of the coroutine.

For Windows Exception handling model, a frontend should attach a funclet bundle
referring to an enclosing cleanuppad as follows:

```
    ehcleanup:
      %tok = cleanuppad within none []
      %unused = call i1 @llvm.coro.end(i8* null, i1 true) [ "funclet"(token %tok) ]
      cleanupret from %tok unwind label %RestOfTheCleanup
```

The `CoroSplit` pass, if the funclet bundle is present, will insert
``cleanupret from %tok unwind to caller`` before
the `coro.end`_ intrinsic and will remove the rest of the block.

Reviewers: majnemer

Reviewed By: majnemer

Subscribers: llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D25543

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297223 91177308-0d34-0410-b5e6-96231b3b80d8
2017-03-07 21:00:54 +00:00
..
_ocamldoc
_static Fix some typos in the doc 2016-08-28 20:29:18 +00:00
_templates
_themes/llvm-theme
CommandGuide lit.rst: Fix sphinx complaint about multiple option definitions 2017-02-09 23:03:22 +00:00
Frontend [docs][PerformanceTips] Add text on allocas and alignment 2015-09-10 17:03:10 +00:00
HistoricalNotes
PDB Add documentation for the PDB Module Info stream. 2016-11-29 22:14:56 +00:00
Proposals fix some typos in the doc 2017-01-14 11:37:01 +00:00
TableGen [X86][AVX512] Adding new LLVM TableGen backend which generates the EVEX2VEX compressing tables. 2017-03-07 08:11:19 +00:00
tutorial Remove redundant code block and update comment. 2017-03-04 14:00:44 +00:00
AdvancedBuilds.rst Fixing autocorrect changing cmake->make 2016-03-18 22:11:51 +00:00
AliasAnalysis.rst [Docs] Add initial MemorySSA documentation. 2016-08-17 00:17:29 +00:00
AMDGPUUsage.rst AMDGPU : AMDGPU : Update AMDGPU Trap Handler ABI. 2017-02-21 18:48:01 +00:00
ARM-BE-bitcastfail.png
ARM-BE-bitcastsuccess.png
ARM-BE-ld1.png
ARM-BE-ldr.png
Atomics.rst fix some various typos in the doc 2016-07-02 19:28:40 +00:00
BigEndianNEON.rst
BitCodeFormat.rst [docs] Update some obsolete information in BitCodeFormat docs. 2016-10-14 16:23:09 +00:00
BlockFrequencyTerminology.rst
BranchWeightMetadata.rst Add function importing info from samplepgo profile to the module summary. 2017-02-28 18:09:44 +00:00
Bugpoint.rst
CMake.rst [docs] Point to upstream Sphinx install instructions. 2017-01-22 03:47:49 +00:00
CMakeLists.txt [cmake] Support overriding remaining HTML doc install directories 2016-09-27 19:52:29 +00:00
CMakePrimer.rst [docs] fix cmake code-block warning 2016-07-20 09:47:09 +00:00
CodeGenerator.rst [docs] Fix typo 2017-02-09 23:02:37 +00:00
CodeOfConduct.rst [Conduct] Refine what "rare cases" means wrt violations outside our spaces. 2016-07-06 19:32:41 +00:00
CodingStandards.rst Fix some remaining documentation references to MSVC 2013 2016-12-15 19:08:02 +00:00
CommandLine.rst Update CommandLine.rst getRegisteredOptions example 2016-11-07 02:43:01 +00:00
CompileCudaWithLLVM.rst [Docs] Update docs to indicate that CUDA compilation is supported on Windows. 2017-01-05 16:54:28 +00:00
CompilerWriterInfo.rst [docs] fix link to AMD manuals (PR30946) 2016-11-08 16:49:24 +00:00
conf.py docs/conf.py: Suppress sphinx highlighting failure warnings 2017-02-10 00:00:22 +00:00
Coroutines.rst [coroutines] Add handling for unwind coro.ends 2017-03-07 21:00:54 +00:00
CoverageMappingFormat.rst fix some typos in the doc 2017-01-14 11:37:01 +00:00
DebuggingJITedCode.rst
DeveloperPolicy.rst Update Bugzilla URLs in docs 2017-02-17 08:26:11 +00:00
doxygen-mainpage.dox [docs] Updated docs to work with Doxygen 1.8.11 2016-03-06 03:50:08 +00:00
doxygen.cfg.in [docs] Tell Doxygen to expand LLVM_ALIGNAS to nothing 2017-01-19 13:37:42 +00:00
Dummy.html
ExceptionHandling.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
ExtendedIntegerResults.txt
ExtendingLLVM.rst [WinEH] Add llvm.eh.exceptionpointer intrinsic 2015-09-03 09:15:32 +00:00
Extensions.rst Make it possible to set SHF_LINK_ORDER explicitly. 2017-02-09 14:59:20 +00:00
FAQ.rst fix some typos in the doc 2016-07-28 09:28:58 +00:00
FaultMaps.rst Fix the docs build 2017-02-07 20:36:03 +00:00
GarbageCollection.rst Tidy up example of getting the pointer size. 2016-10-14 05:45:46 +00:00
gcc-loops.png
GetElementPtr.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
GettingStarted.rst [docs] Add information about how to checkout polly to getting started page 2017-02-23 14:27:07 +00:00
GettingStartedVS.rst [doc] Remove explicit CMake version requirement for MSVC 2016-11-09 01:44:42 +00:00
GlobalISel.rst [AArch64][GlobalISel] Legalize narrow scalar ops again. 2017-01-23 21:10:05 +00:00
GoldPlugin.rst Revert 'Test commit as per developer policy' 2016-11-30 08:24:43 +00:00
HowToAddABuilder.rst [docs] Document the staging buildbot 2017-02-05 21:21:23 +00:00
HowToBuildOnARM.rst [Docs] Change ARM build info to CMake 2015-11-06 18:39:34 +00:00
HowToCrossCompileLLVM.rst [docs] Fix unexpected indentation in HowToCrossCompileLLVM.rst 2016-05-10 14:02:46 +00:00
HowToReleaseLLVM.rst Adding RELEASE_TESTERS.TXT 2016-07-21 16:46:44 +00:00
HowToSetUpLLVMStyleRTTI.rst
HowToSubmitABug.rst Update Bugzilla URLs in docs 2017-02-17 08:26:11 +00:00
HowToUseAttributes.rst
HowToUseInstrMappings.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
InAlloca.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
index.rst [PDB] Begin adding documentation for the PDB file format. 2016-11-10 19:24:21 +00:00
LangRef.rst Fix a typo. Patch by fcrick on github https://github.com/llvm-mirror/llvm/pull/23 2017-03-04 14:01:38 +00:00
Lexicon.rst Update Bugzilla URLs in docs 2017-02-17 08:26:11 +00:00
LibFuzzer.rst [libFuzzer] better link for trophies 2017-01-18 00:45:02 +00:00
LinkTimeOptimization.rst [docs] Typos and whitespace fixed in LTO docs. 2016-11-29 18:00:31 +00:00
linpack-pc.png
LLVMBuild.rst Test commit. 2016-12-24 17:26:38 +00:00
LLVMBuild.txt
make.bat
Makefile.sphinx Bring back Makefile.sphinx 2016-03-23 00:30:57 +00:00
MarkedUpDisassembly.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
MCJIT-creation.png
MCJIT-dyld-load.png
MCJIT-engine-builder.png
MCJIT-load-object.png
MCJIT-load.png
MCJIT-resolve-relocations.png
MCJITDesignAndImplementation.rst Fix several accidental DOS line endings in source files 2016-01-03 17:22:03 +00:00
MemorySSA.rst Fix some typos in the doc 2016-08-28 20:29:18 +00:00
MergeFunctions.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
MIRLangRef.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
NVPTXUsage.rst Update NVVMReflect usage doc to new idiom for adding target-specific early passes. 2017-01-27 19:44:24 +00:00
OptBisect.rst Fix doc for -opt-bisect-limit: the LTO option prefix for lld is -mllvm 2017-02-10 17:16:00 +00:00
Packaging.rst
Passes.rst Remove the ScalarReplAggregates pass 2016-06-15 00:19:09 +00:00
Phabricator.rst [doc] Fix minor grammatical error in Phabricator.rst 2017-01-05 13:08:14 +00:00
ProgrammersManual.rst Revert commit r296967, no typo 2017-03-05 07:46:24 +00:00
Projects.rst
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README.txt [docs] Update the docs to describe how to build the docs with cmake 2016-02-07 15:42:12 +00:00
ReleaseNotes.rst Don't try to link to the 4.0 release notes 2017-02-09 23:03:34 +00:00
ReleaseProcess.rst [OPENMP] Make -fopenmp to turn on OpenMP support by default. 2015-12-10 05:45:58 +00:00
ReportingGuide.rst fix some various typos in the doc 2016-07-02 19:28:40 +00:00
ScudoHardenedAllocator.rst [docs] Documentation update for Scudo 2017-02-09 16:07:52 +00:00
SegmentedStacks.rst [docs] Fixing Sphinx warnings to unclog the buildbot 2016-07-20 12:16:38 +00:00
SourceLevelDebugging.rst [docs] Fix some typos. NFC. 2016-11-01 23:55:50 +00:00
SphinxQuickstartTemplate.rst
StackMaps.rst [Stackmap] Added callsite counts to emitted function information. 2016-09-14 20:22:03 +00:00
Statepoints.rst Update Bugzilla URLs in docs 2017-02-17 08:26:11 +00:00
SystemLibrary.rst
TableGenFundamentals.rst
TestingGuide.rst [docs] cleanup documentation on lit substitutions 2017-02-09 14:12:30 +00:00
TestSuiteMakefileGuide.rst Fix the docs I broke 2016-03-11 23:31:02 +00:00
TypeMetadata.rst IR: New representation for CFI and virtual call optimization pass metadata. 2016-06-24 21:21:32 +00:00
Vectorizers.rst
WritingAnLLVMBackend.rst fix some typos in the doc 2017-01-14 11:37:01 +00:00
WritingAnLLVMPass.rst [docs] Make WritingAnLLVMPass.rst up-to-date with current state of things 2016-09-27 12:07:21 +00:00
XRay.rst [XRay][Docs] Update the XRay documentation 2017-02-28 22:01:26 +00:00
yaml2obj.rst
YamlIO.rst fix some typos in the doc 2017-01-14 11:37:01 +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 <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` <-> `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-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.
`http://llvm.org/docs/CommandGuide/Foo.html`.

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

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

    cd docs/
    make -f Makefile.sphinx linkcheck