LLVM STRING OBFUSCATION LIKE IT'S 2024

Tested on llvm 18 through 20.

Some Notes

• Tested with the repo builds from https://apt.llvm.org/
• /usr/bin/clang++-18 -shared -O0 -o ObfString.so StrObfuscate.cpp -fPIC command in run.sh
• /usr/bin/clang-18 -O1 -fpass-plugin=../ObfString.so main.c -o test command under demo dir's run.sh
• Default build uses a decodeStub that's implemented inline with llvm IRBuilder calls etc.
• Pass -D OBFS_XOR_EXTERN is you want to build the module version that uses the external decodeStub.ll
• clang-18 -O1 -emit-llvm decodeStub.c -c -o decodeStub.bc && llvm-dis-18 decodeStub.bc command used to generate decodeStub.ll from decodeStub.c