In the previous installment of this series we saw how flang parses the statements using an LR(1) algorithm. As the parser recognized the parts of the statements it invokes semantic actions. Today we’re going to talk more about them.

In the last installment we saw how flang splits the input in tokens. Once we have the tokens identified we need to parse them.

In the last chapter we saw how the driver handles the compilation and how it invokes flang1 and flang2. In this chapter we are going to start with flang1.

In the previous installment of this series we saw basically how to install flang and we ran a simple smoke test. In this post we will see a high level overview of what happens when we compile a Fortran program using flang. We will also compare it with what usually happens with clang.

Flang is an open source project to create a Fortran compiler for LLVM. It is based on NVIDIA/PGI Fortran and it has been released under Apache License 2.0. In this series we will do a walk-through the code of this compiler and how it has been integrated in the existing LLVM infrastructure.