LLVM

此处也顺带去整理LLDB所属的开源项目LLVM的相关内容：

• LLVM
  • =Low Level Virtual Machine
  • 是什么=一句话描述
    • 一套用于构建出高度优化的编译器、优化器、运行环境的工具集合的开源项目
      • a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.
  • 主要包含3个部分
    • LLVM套件=LLVM Suite
      • 包含各种
        • 工具
          • 汇编器=assembler
          • 反汇编器=disassembler
          • 位码分析器=bitcode analyzer
          • 位码优化器=bitcode optimizer
          • 简单的回归测试
            • 用于测试LLVM工具和Clang前端
        • 库
        • 头文件
    • Clang=Clang前端=Clang front end
      • 是什么：LLVM的内置的原生的C/C++/Objective-C编译器
      • 可以把C, C++, Objective-C和Objective-C++的代码，编译成LLVM bitcode
        • 然后就可以用LLVM套件去操作此（编译后的）程序了
    • 测试套件=Test Suite
      • 一堆工具的集合
        • 测试LLVM的功能和性能
  • 子项目
    • LLVM Core libraries
      • a modern source- and target-independent optimizer, along with code generation support for many popular CPUs
    • Clang
      • an LLVM native C/C++/Objective-C compiler
    • LLDB
      • a great native debugger
        • 基于LLVM和Clang
    • libc++和libc++ ABI
      • a standard conformant and high-performance implementation of the C++ Standard Library
        • including full support for C++11 and C++14
    • compiler-rt
      • provides highly tuned implementations of the low-level code generator
    • MLIR
      • a novel approach to building reusable and extensible compiler infrastructure
    • OpenMP
      • an OpenMP runtime for use with the OpenMP implementation in Clang
    • polly
      • a suite of cache-locality optimizations as well as auto-parallelism and vectorization using a polyhedral model
    • libclc
      • implement the OpenCL standard library
    • klee
      • implements a "symbolic virtual machine" which uses a theorem prover to try to evaluate all dynamic paths through a program in an effort to find bugs and to prove properties of functions
    • LLD
      • a new linker
        • a drop-in replacement for system linkers and runs much faster
  • 资料
    • 官网
      • The LLVM Compiler Infrastructure Project
        • https://llvm.org
    • 快速上手
      • Getting Started with the LLVM System — LLVM 12 documentation
        • https://llvm.org/docs/GettingStarted.html
  • 相关
    • 概念
      • IR=Intermediate Representation=中间表示层