LLVM Cookbook

Converting IR to LLVM bitcode

In this recipe, you will learn to generate LLVM bit code from IR. The LLVM bit code file format (also known as bytecode) is actually two things: a bitstream container format and an encoding of LLVM IR into the container format.

Getting Ready

The llvm-as tool must be installed in the PATH.

How to do it...

Do the following steps:

1. First create an IR code that will be used as input to llvm-as:

   $ cat test.ll
   define i32 @mult(i32 %a, i32 %b) #0 {
     %1 = mul nsw i32 %a, %b
     ret i32 %1
   }
   

2. To convert LLVM IR in test.ll to bitcode format, you need to use the following command:

   llvm-as test.ll –o test.bc
   

3. The output is generated in the test.bc file, which is in bit stream format; so, when we want to have a look at output in text format, ...