SUB2r Firmware using LLVM/CLANG.

A lot of dependency on the ARM GCC compiler, its issues and required updates have lead us to take a chance of integrating our code under a newer and modern compiler. The choice of which has become the LLVM/CLANG compiler. Usage of the most reliable and feature rich IDE the MS Visual Studio we had integrated our SUB2r Firmware into before, has given us a chance to update the compiler to LLVM/CLANG. MS Visual Studio itself includes both the ARM GCC and the LLVM/CLANG compilers but the frequently updated one is the LLVM/CLANG with rich benefits of static analysis, small code size and many other advantages.

This article is meant to give the reader all the experiences, lessons learnt during the transfer from GCC to LLVM/CLANG. The article contains guidelines and step-by-step instructions for the migration with the failures we had, what problems we faced and how to overcome those issues. We hope to give all the information with details so that the readers can find the solutions they need.

Note: The focus will mostly be the integration process to LLVM/CLANG from ARM GCC we will not dive into LLVM/CLANG features.