MICRO Compiler

A compiler for MICRO language designed using C++, Flex and Bison.

Scope

This compiler compiles correctly for code including Statements, Expressions and Function calls. Conditionals and loops are not implemented. To see sample code files see sample_input

Guide

Build the Compiler

To build the compiler first install flex and bison. You can use the following commands for Ubuntu:

sudo apt-get install flex

sudo apt-get install bison

Then clone this repository and run the following command from inside the directory

make compiler

Generate the assembly code

The above command will generate file named micro and this is our compiler. To compile your MICRO code use following command

./micro path/to/input_file

You can test using the sample input files provided.

Interpreting the assembly code

The compiler will generate assembly level code. To interpret the assembly level code we will use Tiny (a very simple assembly code interpreter). You can check it's the documentation of here.

Build the interpreter using

make interpreter

and then run

./tiny input file

The input file in this step is the output generated from above step.

Understanding the code

Main parts of this compiler are:

1. Lexical analyzer: This is written using flex and code is in the file scanner.l. During this phase the code is converted into sequence to tokens which is the fed to the parser.
2. Parser: This is written using bison and code is in the file parser.y. This step involves parsing the input code. A context free grammar is defined for this language and any valid piece of code can be generated using the grammar.
3. Code Generation: Code Generation is divided into two parts. First Three Address Code in generated which is then converted into assembly level code. This code can be found in utils. This step involves building the symbol table and generating the Abstract Syntax Tree. An intermediate three address code is generated by performing post-order traversal of the AST. Then the intermediate code in converted to assembly code.

About

This project was done as part of CS406 Compilers course at IIT Dharwad in Spring 2020 Semester. The interpreter is not written by me and was provided.