LLVM is a compiler infrastructure which contains all steps of the compilation.
First created for the optimization of source code for the compilation unrelated
to any specific language. LLVM allows numerous pieces of source code to be translated
in different targets.
In our case, we will be interested in how we can use LLVM-IR
for the Tiger Compiler.
The LLVM IR is a Static Single Assignment (SSA) based
representation that provides type safety, low-level operations,
and is capable of representing most of high-level languages cleanly.
It is the intermediate representation used by Clang, A C language family front end for LLVM.
Compared to the HIR, LLVM IR is typed. Providing type information
can help the LLVM back end to optimize even more.
LLVM is a project written in C++, parts of the code will be explained in further sections.
For a more thorough understanding of LLVM’s inner workings, you are strongly encouraged
to read the actual LLVM documentation linked above. This section documents some of
the most useful LLVM classes for our implementation of the Tiger Compiler:
