=============================================== llvm-libc: An ISO C-conformant Standard Library

llvm-libc library is not complete. If you need a fully functioning libc right now, you should continue to use your standard system libc.

.. contents:: Table of Contents :depth: 4 :local:

Introduction

The libc aspires to a unique place in the software ecosystem. The goals are:

  • Fully compliant with current C standards (C17 and upcoming C2x) and POSIX.
  • Easily decomposed and embedded: Supplement or replace system C library functionality easily. This is useful to get consistent math precision across systems, or updated memory operations for newer microarchitectures. These pieces will work on Linux, MacOS, Windows, and Fuchsia.
  • The creation of fully static binaries without license implications.
  • Increase whole program optimization opportunities for static binaries through ability to inline math and memory operations.
  • Reduce coding errors by coding in modern C++ through the use of lightweight containers during coding that can be optimized away at runtime.
  • Permit fuzzing and sanitizer instrumentation of user binaries including the libc functions.
  • A complete testsuite that tests both the public interface and internal algorithms.
  • Fuzzing__

.. __: https://github.com/llvm/llvm-project/tree/main/libc/fuzzing

Platform Support

Most development is currently targeting x86_64 and aarch64 on Linux. Several functions in llvm-libc have been tested on Windows. The Fuchsia platform is slowly replacing functions from its bundled libc with functions from llvm-libc.

ABI Compatibility

llvm-libc is written to be ABI independent. Interfaces are generated using LLVM's tablegen, so supporting arbitrary ABIs is possible. In it's initial stages llvm-libc is not offering ABI stability in any form.

Other Interesting Documentation

.. toctree::

build_system
clang_tidy_checks
entrypoints
fuzzing
ground_truth_specification
header_generation
implementation_standard
api_test
layering
mechanics_of_public_api
redirectors
source_layout
strings
runtimes_build
stdio
math