llvm-6502/docs
Adrian Prantl 02474a32eb Move the complex address expression out of DIVariable and into an extra
argument of the llvm.dbg.declare/llvm.dbg.value intrinsics.

Previously, DIVariable was a variable-length field that has an optional
reference to a Metadata array consisting of a variable number of
complex address expressions. In the case of OpPiece expressions this is
wasting a lot of storage in IR, because when an aggregate type is, e.g.,
SROA'd into all of its n individual members, the IR will contain n copies
of the DIVariable, all alike, only differing in the complex address
reference at the end.

By making the complex address into an extra argument of the
dbg.value/dbg.declare intrinsics, all of the pieces can reference the
same variable and the complex address expressions can be uniqued across
the CU, too.
Down the road, this will allow us to move other flags, such as
"indirection" out of the DIVariable, too.

The new intrinsics look like this:
declare void @llvm.dbg.declare(metadata %storage, metadata %var, metadata %expr)
declare void @llvm.dbg.value(metadata %storage, i64 %offset, metadata %var, metadata %expr)

This patch adds a new LLVM-local tag to DIExpressions, so we can detect
and pretty-print DIExpression metadata nodes.

What this patch doesn't do:

This patch does not touch the "Indirect" field in DIVariable; but moving
that into the expression would be a natural next step.

http://reviews.llvm.org/D4919
rdar://problem/17994491

Thanks to dblaikie and dexonsmith for reviewing this patch!

Note: I accidentally committed a bogus older version of this patch previously.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218787 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-01 18:55:02 +00:00
..
_static
_templates
_themes/llvm-theme
CommandGuide
HistoricalNotes
TableGen
tutorial
AliasAnalysis.rst
ARM-BE-bitcastfail.png
ARM-BE-bitcastsuccess.png
ARM-BE-ld1.png
ARM-BE-ldr.png
Atomics.rst
BigEndianNEON.rst
BitCodeFormat.rst
BlockFrequencyTerminology.rst
BranchWeightMetadata.rst
Bugpoint.rst
CMake.rst
CMakeLists.txt
CodeGenerator.rst
CodingStandards.rst
CommandLine.rst
CompilerWriterInfo.rst
conf.py
CoverageMappingFormat.rst
DebuggingJITedCode.rst
DeveloperPolicy.rst
doxygen.cfg.in
doxygen.css
doxygen.footer
doxygen.header
doxygen.intro
Dummy.html
ExceptionHandling.rst
ExtendedIntegerResults.txt
ExtendingLLVM.rst
Extensions.rst
FAQ.rst
GarbageCollection.rst
gcc-loops.png
GetElementPtr.rst
GettingStarted.rst
GettingStartedVS.rst
GoldPlugin.rst
HowToAddABuilder.rst
HowToBuildOnARM.rst
HowToCrossCompileLLVM.rst
HowToReleaseLLVM.rst
HowToSetUpLLVMStyleRTTI.rst
HowToSubmitABug.rst
HowToUseAttributes.rst
HowToUseInstrMappings.rst
InAlloca.rst
index.rst
LangRef.rst
Lexicon.rst
LinkTimeOptimization.rst
linpack-pc.png
LLVMBuild.rst
LLVMBuild.txt
make.bat
Makefile
Makefile.sphinx
MakefileGuide.rst
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
Packaging.rst
Passes.rst
Phabricator.rst
ProgrammersManual.rst
Projects.rst
re_format.7
README.txt
ReleaseNotes.rst
ReleaseProcess.rst
SegmentedStacks.rst
SourceLevelDebugging.rst Move the complex address expression out of DIVariable and into an extra 2014-10-01 18:55:02 +00:00
SphinxQuickstartTemplate.rst
StackMaps.rst
SystemLibrary.rst
TableGenFundamentals.rst
TestingGuide.rst
TestSuiteMakefileGuide.rst
Vectorizers.rst
WritingAnLLVMBackend.rst
WritingAnLLVMPass.rst
yaml2obj.rst
YamlIO.rst

LLVM Documentation
==================

LLVM's documentation is written in reStructuredText, a lightweight
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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
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    cd docs/
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These .rst files are also included during HTML generation so they are also
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==============

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