User Guides¶
NOTE: If you are a user who is only interested in using an LLVM-based compiler, you should look into Clang instead. The documentation here is intended for users who have a need to work with the intermediate LLVM representation.
Clang¶
- How To Build On ARM
- Notes on building and testing LLVM/Clang on ARM.
- How To Build Clang and LLVM with Profile-Guided Optimizations
- Notes on building LLVM/Clang with PGO.
- How To Cross-Compile Clang/LLVM using Clang/LLVM
- 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.
- LLVM Code Coverage Mapping Format
- This describes the format and encoding used for LLVM’s code coverage mapping.
- Control Flow Verification Tool Design Document
- A description of the verification tool for Control Flow Integrity.
LLVM Builds and Distributions¶
- Building a Distribution of LLVM
- A best-practices guide for using LLVM’s CMake build system to package and distribute LLVM-based tools.
- Building LLVM with CMake
- An addendum to the main Getting Started guide for those using the CMake build system.
- A guide to Dockerfiles for building LLVM
- A reference for using Dockerfiles provided with LLVM.
- Support Library
- This document describes the LLVM Support Library (
lib/Support) and how to keep LLVM source code portable. - Advanced Build Configurations
- This document describes more advanced build configurations.
Optimizations¶
- Writing an LLVM Pass
- Information on how to write LLVM transformations and analyses.
- Writing an LLVM Pass
- Information on how to write LLVM transformations under the new pass manager.
- LLVM’s Analysis and Transform Passes
- A list of optimizations and analyses implemented in LLVM.
- Stack Safety Analysis
- This document describes the design of the stack safety analysis of local variables.
- MergeFunctions pass, how it works
- Describes functions merging optimization.
- LLVM Alias Analysis Infrastructure
- Information on how to write a new alias analysis implementation or how to use existing analyses.
- MemorySSA
- Information about the MemorySSA utility in LLVM, as well as how to use it.
- LLVM Loop Terminology (and Canonical Forms)
- A document describing Loops and associated terms as used in LLVM.
- Auto-Vectorization in LLVM
- This document describes the current status of vectorization in LLVM.
- LLVM Link Time Optimization: Design and Implementation
- This document describes the interface between LLVM intermodular optimizer and the linker and its design
- The LLVM gold plugin
- How to build your programs with link-time optimization on Linux.
- Remarks
- A reference on the implementation of remarks in LLVM.
- Source Level Debugging with LLVM
- This document describes the design and philosophy behind the LLVM source-level debugger.
Code Generation¶
- Writing an LLVM Backend
- Information on how to write LLVM backends for machine targets.
- The LLVM Target-Independent Code Generator
- 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.
- TableGen
- Describes the TableGen tool, which is used heavily by the LLVM code generator.
JIT¶
- MCJIT Design and Implementation
- Describes the inner workings of MCJIT execution engine.
- Debugging JIT-ed Code
- How to debug JITed code with GDB.
How to debug JITed code with GDB.
Additional Topics¶
- CommandLine 2.0 Library Manual
- Provides information on using the command line parsing library.
- Extending LLVM: Adding instructions, intrinsics, types, etc.
- Look here to see how to add instructions and intrinsics to LLVM.
- How To Add A Constrained Floating-Point Intrinsic
- Gives the steps necessary when adding a new constrained math intrinsic to LLVM.
- How to Cross Compile Compiler-rt Builtins For Arm
- Notes on cross-building and testing the compiler-rt builtins for Arm.
- Using ARM NEON instructions in big endian mode
- LLVM’s support for generating NEON instructions on big endian ARM targets is somewhat nonintuitive. This document explains the implementation and rationale.
- Compiling CUDA with clang
- LLVM support for CUDA.
- User Guide for NVPTX Back-end
- This document describes using the NVPTX backend to compile GPU kernels.
- User Guide for AMDGPU Backend
- This document describes using the AMDGPU backend to compile GPU kernels.
- DWARF Extensions For Heterogeneous Debugging
- This document describes DWARF extensions to support heterogeneous debugging for targets such as the AMDGPU backend.