Glorified Calculator Compiler

just so that i can say gcc.

Made this for a uni project. Lot of fun and I keep coming back to find new improvements in design/readability/portability. The compiler was made using Antlr4.

Info about the language (grammar/tokens) can be found at the bottom. I will not "improve" the actual spec to stay true to the requirements.

The project is completely packaged and easily run using Maven. Even includes the Mars MIPS emulator, Mars4_5.jar to run the compiled programs. See below

Building and running the compiler

You need Maven and a JDK (JDK 14+ should work but prefer 17+). If you use Intellij IDEA, you have both already. However Maven might not be in your PATH, so you will only be able to run Maven commands from your IDE.

To build from terminal, run the following with your directory set to the project's root

mvn clean package

This will download dependencies, generate the parser from myLanguage.g4, and finally generate the mlc.jar compiler executable for this language.

You can then run the compiler with

java -jar .\target\mlc.jar

Without arguments, a usage message will be displayed. You can then add file arguments to compile as you wish.

Terminal Use example (current dir is project root)

> mvn clean package
> dir .\target\

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
d-----         24/6/2024  12:27 πμ                archive-tmp
d-----         24/6/2024  12:27 πμ                classes
d-----         24/6/2024  12:27 πμ                generated-sources
d-----         24/6/2024  12:27 πμ                generated-test-sources
d-----         24/6/2024  12:27 πμ                maven-status
d-----         24/6/2024  12:27 πμ                test-classes
-a----         24/6/2024  12:27 πμ       16901728 mlc.jar


> java -jar .\target\mlc.jar  .\res\ProgramExamples\FibonacciExample


# This will generate the FibonacciExample.asm MIPS Assembly file 
# You can then run it with

> java -jar .\Mars4_5.jar .\res\ProgramExamples\FibonacciExample.asm

# Output:

MARS 4.5  Copyright 2003-2014 Pete Sanderson and Kenneth Vollmar

1
2
3
5
8
13
21
34
55
89

Sample Program & More Specs

Example of printing the first 10 Fibonacci numbers:

mainclass Fibonacci {
    public static void main ( ) {
        int first, second, i, tmp;
        first = 0;
        second = 1;
        
        i = 0;
        while (i < 10) {
            tmp = first + second;
            println(tmp);
            
            first=second;
            second=tmp;
            i = i + 1;
        }
    }
}

Integers are 31-bit signed.
Floats are in the approximate range (10^-58, 10^57).

myLanguage.g4 contains the Antlr4 definition of the language's tokens and grammar (compiler implementation language independent).
Compile is the starting class that initialises the Antlr4 lexer and parser. The result tree is visited with a custom visitor to generate the MIPS assembly code.
MIPSCodeGeneratorVisitor is the visitor class that does all the code generation and file handling. Heaviest read in the project for sure. Might try to split a few components at some point.
ProgramExamples/ contains sample programs in the language that compile succesfully.
CompileErrorFiles/ contains sample programs that will not compile and throw an exception. Used for tests.

Tokens

plus some reserved words such as "public", "main", etc. Reserved words are defined in myLanguage.g4

Grammar