Writing an LLVM Backend#
Introduction#
This document describes techniques for writing compiler backends that convert the LLVM Intermediate Representation (IR) to code for a specified machine or other languages. Code intended for a specific machine can take the form of either assembly code or binary code (usable for a JIT compiler).
The backend of LLVM features a target-independent code generator that may create output for several types of target CPUs — including X86, PowerPC, ARM, and SPARC. The backend may also be used to generate code targeted at SPUs of the Cell processor or GPUs to support the execution of compute kernels.
The document focuses on existing examples found in subdirectories of
llvm/lib/Target in a downloaded LLVM release. In particular, this document
focuses on the example of creating a static compiler (one that emits text
assembly) for a SPARC target, because SPARC has fairly standard
characteristics, such as a RISC instruction set and straightforward calling
conventions.