AutoPatch uses a custom version of LLVM to instrument the functions and generate hotpatches for C files. In particular, AutoPatch uses branch release/13.x of LLVM but with additional functions necessary to instrument and compile into LLVM IR. For example, AutoPatch uses BasicBlock::getFirstNonPHIOrDbgOrAlloca(), which was added in release/16.x. As such, to run AutoPatch, LLVM must be modified by hand to include these additional functions. This document describes how to modify LLVM to include these additional functions.
As mentioned in the main README, the following files must be modified:
llvm-project/llvm/include/llvm/IR/BasicBlock.h
llvm-project/llvm/include/llvm/IR/IRBuilder.h
llvm-project/llvm/lib/IR/BasicBlock.cpp
To do so, simply copy the 3 files from this directory into the corresponding files in your local LLVM project directory.