LLVM是Low Level Virtual Machine 的縮寫，最早開始於伊利諾(Illinois)大學的研究計畫，目標是提供一個高度模組化及可重覆使用的編譯器(Compiler)與相關工具組(Tool-chain)的集合。LLVM之下包含了許多的子計畫，包括了core library、clang、lldb、compiler-rt、openMP、libclc 等等，透過這些額外的子計畫展現了LLVM多功能性、靈活性與高度的可重覆使用性， 提供在開放原始碼Tool-chain的一個新的選擇，本文將就使用經驗、偵錯的方便性及效能差異上與以往常用的GCC(GNU Compiler Collection)做一個比較。

LLVM is the abbreviation for Low Level Virtual Machine. It began a s a research project at theUniversity of Illinois. The goal of this project is to provide a collection of highly modular and reusable compilerand tool-chain.LLVM consists of a number of subprojects such as core library, clang, lldb, compiler-rt, openMP, libclcand so on. Through these subprojects, LLVM shows its versatility, flexibility, and reusability . Undoubtedly, itgives us a new choice of open source code tool-chain. This article will present the comparison of debug abilityand performance with GCC (GNU Compiler Collection) based on user experiences.