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It's currently ambiguous in IR whether the source language explicitly did not want a stack a stack protector (in C, via function attribute no_stack_protector) or doesn't care for any given function. It's common for code that manipulates the stack via inline assembly or that has to set up its own stack canary (such as the Linux kernel) would like to avoid stack protectors in certain functions. In this case, we've been bitten by numerous bugs where a callee with a stack protector is inlined into an __attribute__((__no_stack_protector__)) caller, which generally breaks the caller's assumptions about not having a stack protector. LTO exacerbates the issue. While developers can avoid this by putting all no_stack_protector functions in one translation unit together and compiling those with -fno-stack-protector, it's generally not very ergonomic or as ergonomic as a function attribute, and still doesn't work for LTO. See also: https://lore.kernel.org/linux-pm/20200915172658.1432732-1-rkir@google.com/ https://lore.kernel.org/lkml/20200918201436.2932360-30-samitolvanen@google.com/T/#u Typically, when inlining a callee into a caller, the caller will be upgraded in its level of stack protection (see adjustCallerSSPLevel()). By adding an explicit attribute in the IR when the function attribute is used in the source language, we can now identify such cases and prevent inlining. Block inlining when the callee and caller differ in the case that one contains `nossp` when the other has `ssp`, `sspstrong`, or `sspreq`. Fixes pr/47479. Reviewed By: void Differential Revision: https://reviews.llvm.org/D87956 |
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_ocamldoc | ||
_static | ||
_templates | ||
_themes/llvm-theme | ||
AMDGPU | ||
CommandGuide | ||
DependenceGraphs | ||
Frontend | ||
GlobalISel | ||
HistoricalNotes | ||
PDB | ||
Proposals | ||
TableGen | ||
tutorial | ||
AddingConstrainedIntrinsics.rst | ||
AdvancedBuilds.rst | ||
AliasAnalysis.rst | ||
AMDGPUDwarfExtensionsForHeterogeneousDebugging.rst | ||
AMDGPUInstructionNotation.rst | ||
AMDGPUInstructionSyntax.rst | ||
AMDGPUModifierSyntax.rst | ||
AMDGPUOperandSyntax.rst | ||
AMDGPUUsage.rst | ||
ARM-BE-bitcastfail.png | ||
ARM-BE-bitcastsuccess.png | ||
ARM-BE-ld1.png | ||
ARM-BE-ldr.png | ||
Atomics.rst | ||
Benchmarking.rst | ||
BigEndianNEON.rst | ||
BitCodeFormat.rst | ||
BlockFrequencyTerminology.rst | ||
BranchWeightMetadata.rst | ||
BugLifeCycle.rst | ||
Bugpoint.rst | ||
BugpointRedesign.md | ||
BuildingADistribution.rst | ||
CFIVerify.rst | ||
CMake.rst | ||
CMakeLists.txt | ||
CMakePrimer.rst | ||
CodeGenerator.rst | ||
CodeOfConduct.rst | ||
CodeReview.rst | ||
CodingStandards.rst | ||
CommandLine.rst | ||
CompileCudaWithLLVM.rst | ||
CompilerWriterInfo.rst | ||
conf.py | ||
Contributing.rst | ||
Coroutines.rst | ||
CoverageMappingFormat.rst | ||
DebuggingJITedCode.rst | ||
DeveloperPolicy.rst | ||
Docker.rst | ||
doxygen-mainpage.dox | ||
doxygen.cfg.in | ||
ExceptionHandling.rst | ||
ExtendedIntegerResults.txt | ||
ExtendingLLVM.rst | ||
Extensions.rst | ||
FAQ.rst | ||
FaultMaps.rst | ||
FuzzingLLVM.rst | ||
GarbageCollection.rst | ||
gcc-loops.png | ||
GetElementPtr.rst | ||
GettingInvolved.rst | ||
GettingStarted.rst | ||
GettingStartedTutorials.rst | ||
GettingStartedVS.rst | ||
GitBisecting.rst | ||
GoldPlugin.rst | ||
GwpAsan.rst | ||
HowToAddABuilder.rst | ||
HowToBuildOnARM.rst | ||
HowToBuildWithPGO.rst | ||
HowToCrossCompileBuiltinsOnArm.rst | ||
HowToCrossCompileLLVM.rst | ||
HowToReleaseLLVM.rst | ||
HowToSetUpLLVMStyleRTTI.rst | ||
HowToSubmitABug.rst | ||
HowToUpdateDebugInfo.rst | ||
HowToUseAttributes.rst | ||
HowToUseInstrMappings.rst | ||
InAlloca.rst | ||
index.rst | ||
LangRef.rst | ||
Lexicon.rst | ||
LibFuzzer.rst | ||
LinkTimeOptimization.rst | ||
linpack-pc.png | ||
llvm-objdump.1 | ||
LLVMBuild.rst | ||
LLVMBuild.txt | ||
loop-guard.svg | ||
loop-irreducible.svg | ||
loop-merge.svg | ||
loop-nested.svg | ||
loop-nonmaximal.svg | ||
loop-separate.svg | ||
loop-single.svg | ||
loop-terminology-guarded-loop.png | ||
loop-terminology-initial-loop.png | ||
loop-terminology-rotated-loop.png | ||
loop-terminology.svg | ||
LoopTerminology.rst | ||
make.bat | ||
Makefile.sphinx | ||
MarkdownQuickstartTemplate.md | ||
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 | ||
MeetupGuidelines.rst | ||
MemorySSA.rst | ||
MemTagSanitizer.rst | ||
MergeFunctions.rst | ||
MIRLangRef.rst | ||
NVPTXUsage.rst | ||
OptBisect.rst | ||
ORCv2.rst | ||
Packaging.rst | ||
Passes.rst | ||
Phabricator.rst | ||
ProgrammersManual.rst | ||
Projects.rst | ||
re_format.7 | ||
README.txt | ||
Reference.rst | ||
ReleaseNotes.rst | ||
ReleaseProcess.rst | ||
Remarks.rst | ||
ReportingGuide.rst | ||
ScudoHardenedAllocator.rst | ||
Security.rst | ||
SegmentedStacks.rst | ||
SourceLevelDebugging.rst | ||
speculative_load_hardening_microbenchmarks.png | ||
SpeculativeLoadHardening.md | ||
SphinxQuickstartTemplate.rst | ||
StackMaps.rst | ||
StackSafetyAnalysis.rst | ||
Statepoints.rst | ||
SupportLibrary.rst | ||
SystemLibrary.rst | ||
TableGenFundamentals.rst | ||
TestingGuide.rst | ||
TestSuiteGuide.md | ||
TestSuiteMakefileGuide.rst | ||
TransformMetadata.rst | ||
TypeMetadata.rst | ||
UserGuides.rst | ||
Vectorizers.rst | ||
WritingAnLLVMBackend.rst | ||
WritingAnLLVMNewPMPass.rst | ||
WritingAnLLVMPass.rst | ||
XRay.rst | ||
XRayExample.rst | ||
XRayFDRFormat.rst | ||
yaml2obj.rst | ||
YamlIO.rst |
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 docs/ make -f Makefile.sphinx linkcheck Doxygen page Output ============== Install doxygen <http://www.stack.nl/~dimitri/doxygen/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