User Guides
===========

NOTE: If you are a user who is only interested in using an LLVM-based compiler,
you should look into `Clang <https://clang.llvm.org>`_ instead. The
documentation here is intended for users who have a need to work with the
intermediate LLVM representation.

.. contents::
   :local:

.. toctree::
   :hidden:

   AArch64SME
   AddingConstrainedIntrinsics
   AdminTasks
   AdvancedBuilds
   AliasAnalysis
   AMDGPUUsage
   Benchmarking
   BigEndianNEON
   BuildingADistribution
   CFIVerify
   CMake
   CMakePrimer
   CodeGenerator
   CodeOfConduct
   CommandLine
   CompileCudaWithLLVM
   CoverageMappingFormat
   CycleTerminology
   DebuggingJITedCode
   DirectXUsage
   Docker
   DTLTO
   FatLTO
   ExtendingLLVM
   GitHub
   GoldPlugin
   GlobalISel/MIRPatterns
   HowToBuildOnARM
   HowToBuildWithPGO
   HowToBuildWindowsItaniumPrograms
   HowToCrossCompileBuiltinsOnArm
   HowToCrossCompileLLVM
   HowToUpdateDebugInfo
   InstCombineContributorGuide
   InstrProfileFormat
   InstrRefDebugInfo
   KeyInstructionsDebugInfo
   LFI
   LinkTimeOptimization
   LoopTerminology
   MarkdownQuickstartTemplate
   MemorySSA
   MemProf
   MergeFunctions
   MCJITDesignAndImplementation
   MisExpect
   ORCv2
   OpaquePointers
   JITLink
   NewPassManager
   NVPTXUsage
   Passes
   ReportingGuide
   ResponseGuide
   Remarks
   RemoveDIsDebugInfo
   RISCVUsage
   RISCV/RISCVVectorExtension
   SourceLevelDebugging
   SPIRVUsage
   SandboxIR
   StackSafetyAnalysis
   SupportLibrary
   TableGen/index
   TableGenFundamentals
   Telemetry
   Vectorizers
   WritingAnLLVMPass
   WritingAnLLVMNewPMPass
   WritingAnLLVMBackend
   yaml2obj

Clang
-----

:doc:`HowToBuildOnARM`
   Notes on building and testing LLVM/Clang on ARM.

:doc:`HowToBuildWithPGO`
    Notes on building LLVM/Clang with PGO.

:doc:`HowToCrossCompileLLVM`
   Notes on cross-building and testing LLVM/Clang.

`How to build the C, C++, ObjC, and ObjC++ front end`__
   Instructions for building the clang front-end from source.

   .. __: https://clang.llvm.org/get_started.html

:doc:`CoverageMappingFormat`
  This describes the format and encoding used for LLVM’s code coverage mapping.

:doc:`CFIVerify`
  A description of the verification tool for Control Flow Integrity.

LLVM Builds and Distributions
-----------------------------

:doc:`BuildingADistribution`
  A best-practices guide for using LLVM's CMake build system to package and
  distribute LLVM-based tools.

:doc:`CMake`
   An addendum to the main Getting Started guide for those using the `CMake
   build system <http://www.cmake.org>`_.

:doc:`Docker`
   A reference for using Dockerfiles provided with LLVM.

:doc:`Support Library <SupportLibrary>`
   This document describes the LLVM Support Library (``lib/Support``) and
   how to keep LLVM source code portable.

:doc:`AdvancedBuilds`
   This document describes more advanced build configurations.

Optimizations
-------------

:doc:`WritingAnLLVMNewPMPass`
   Information on how to write LLVM transformations under the new pass
   manager.

:doc:`WritingAnLLVMPass`
   Information on how to write LLVM transformations and analyses under the
   legacy pass manager.

:doc:`Passes`
   A list of optimizations and analyses implemented in LLVM.

:doc:`StackSafetyAnalysis`
  This document describes the design of the stack safety analysis of local
  variables.

:doc:`MergeFunctions`
  Describes functions merging optimization.

:doc:`AliasAnalysis`
   Information on how to write a new alias analysis implementation or how to
   use existing analyses.

:doc:`MemorySSA`
   Information about the MemorySSA utility in LLVM, as well as how to use it.

:doc:`MemProf`
   User guide and internals of MemProf, profile guided optimizations for memory.

:doc:`LoopTerminology`
  A document describing Loops and associated terms as used in LLVM.

:doc:`CycleTerminology`
  A document describing cycles as a generalization of loops.

:doc:`Vectorizers`
   This document describes the current status of vectorization in LLVM.

:doc:`LinkTimeOptimization`
   This document describes the interface between LLVM intermodular optimizer
   and the linker and its design

:doc:`DTLTO`
   This document describes the DTLTO implementation, which allows for
   distributing ThinLTO backend compilations without requiring support from
   the build system.

:doc:`GoldPlugin`
   How to build your programs with link-time optimization on Linux.

:doc:`Remarks`
   A reference on the implementation of remarks in LLVM.

:doc:`Source Level Debugging with LLVM <SourceLevelDebugging>`
   This document describes the design and philosophy behind the LLVM
   source-level debugger.

:doc:`How to Update Debug Info <HowToUpdateDebugInfo>`
   This document specifies how to correctly update debug info in various kinds
   of code transformations.

:doc:`InstrRefDebugInfo`
   This document explains how LLVM uses value tracking, or instruction
   referencing, to determine variable locations for debug info in the final
   stages of compilation.

:doc:`RemoveDIsDebugInfo`
   This is a migration guide describing how to move from debug info using
   intrinsics such as dbg.value to using the non-instruction DbgRecord object.

:doc:`KeyInstructionsDebugInfo`
   This document explains how the debug info feature Key Instructions is
   implemented in LLVM.

:doc:`InstrProfileFormat`
   This document explains two binary formats of instrumentation-based profiles.

:doc:`InstCombineContributorGuide`
   This document specifies guidelines for contributions for InstCombine and
   related passes.


Code Generation
---------------

:doc:`WritingAnLLVMBackend`
   Information on how to write LLVM backends for machine targets.

:doc:`CodeGenerator`
   The design and implementation of the LLVM code generator.  Useful if you are
   working on retargetting LLVM to a new architecture, designing a new codegen
   pass, or enhancing existing components.

:doc:`TableGen <TableGen/index>`
   Describes the TableGen tool, which is used heavily by the LLVM code
   generator.

==========
GlobalISel
==========

:doc:`MIRPatterns <GlobalISel/MIRPatterns>`
   Describes the design of MIR Patterns and how to use them.

===
JIT
===

:doc:`MCJITDesignAndImplementation`
   Describes the inner workings of MCJIT execution engine.

:doc:`ORCv2`
   Describes the design and implementation of the ORC APIs, including some
   usage examples, and a guide for users transitioning from ORCv1 to ORCv2.

:doc:`JITLink`
   Describes the design and APIs for the JITLink library, ORC's new JIT
   linker.

:doc:`DebuggingJITedCode`
   How to debug JITed code with GDB.

Additional Topics
-----------------

:doc:`CommandLine`
  Provides information on using the command line parsing library.

:doc:`ExtendingLLVM`
  Look here to see how to add instructions and intrinsics to LLVM.

:doc:`AddingConstrainedIntrinsics`
   Gives the steps necessary when adding a new constrained math intrinsic
   to LLVM.

:doc:`HowToBuildWindowsItaniumPrograms`
   Notes on assembling a Windows Itanium environment.

:doc:`HowToCrossCompileBuiltinsOnArm`
   Notes on cross-building and testing the compiler-rt builtins for Arm.

:doc:`BigEndianNEON`
  LLVM's support for generating NEON instructions on big endian ARM targets is
  somewhat nonintuitive. This document explains the implementation and rationale.

:doc:`AArch64SME`
  LLVM's support for AArch64 SME ACLE and ABI.

:doc:`CompileCudaWithLLVM`
  LLVM support for CUDA.

:doc:`NVPTXUsage`
   This document describes using the NVPTX backend to compile GPU kernels.

:doc:`AMDGPUUsage`
   This document describes using the AMDGPU backend to compile GPU kernels.

:doc:`AMDGPUDwarfExtensionsForHeterogeneousDebugging`
   This document describes DWARF extensions to support heterogeneous debugging
   for targets such as the AMDGPU backend.

:doc:`AMDGPUDwarfExtensionAllowLocationDescriptionOnTheDwarfExpressionStack/AMDGPUDwarfExtensionAllowLocationDescriptionOnTheDwarfExpressionStack`
   This document describes a DWARF extension to allow location descriptions on
   the DWARF expression stack. It is part of
   :doc:`AMDGPUDwarfExtensionsForHeterogeneousDebugging`.

:doc:`SPIRVUsage`
   This document describes using the SPIR-V target to compile GPU kernels.

:doc:`DirectXUsage`
   This document describes using the DirectX target to compile GPU code for the
   DirectX runtime.

:doc:`RISCVUsage`
   This document describes using the RISC-V target.

:doc:`RISCV/RISCVVectorExtension`
   This document describes how the RISC-V Vector extension can be expressed in LLVM IR and how code is generated for it in the backend.

:doc:`Sandbox IR <SandboxIR>`
   This document describes the design and usage of Sandbox IR, a transactional layer over LLVM IR.

:doc:`Telemetry`
   This document describes the Telemetry framework in LLVM.

:doc:`LFI <LFI>`
    This document describes the Lightweight Fault Isolation (LFI) target in LLVM.