How to make clang compile to llvm IR

Question

I want clang to compile my C/C++ code to LLVM bytecode rather than binary executable. How can I achieve that? And if I get the LLVM by

Answer 1

If you have multiple files and you don't want to have to type each file, I would recommend that you follow these simple steps (I am using clang-3.8 but you can use any other version):

1. generate all .ll files

   clang-3.8 -S -emit-llvm *.c
   

2. link them into a single one

   llvm-link-3.8 -S -v -o single.ll *.ll
   

3. (Optional) Optimise your code (maybe some alias analysis)

   opt-3.8 -S -O3 -aa -basicaaa -tbaa -licm single.ll -o optimised.ll
   

4. Generate assembly (generates a optimised.s file)

   llc-3.8 optimised.ll
   

5. Create executable (named a.out)

   clang-3.8 optimised.s