MiniJava Compiler

This is a compiler for MiniJava, a subset of the Java programming language. MiniJava supports basic object-oriented features like classes, fields, methods, and single inheritance. It also includes arrays, logical operators, control flow statements, and simple expressions using integers.

Language Overview

Here's a brief overview of what MiniJava supports:

• Class Declaration: Define classes with fields and methods. Fields are protected, and methods are inherently polymorphic (virtual).

• Inheritance: Classes can extend other classes, inheriting their fields and methods. Method overriding is allowed.

• Basic Types: MiniJava supports int, boolean, int[] (arrays of integers), and boolean[] (arrays of booleans).

• Method Calls: Call methods using the dot notation (object.method()), passing parameters as arguments.

• Arrays: Perform array operations, including array access (array[index]) and getting the size of an array using the length attribute.

• Control Flow: MiniJava has if-else statements and while loops for control flow.

• Logical Operators: Supports && (logical AND) and ! (logical NOT) operators.

• Constructor and Destructor: No explicit constructors or destructors; objects are created with the new operator.

• Scoping and Shadowing: Local variables are defined at the beginning of a method and can shadow class fields.

• Static Methods and Fields: MiniJava does not support static methods or fields.

• Special Method main: The main method serves as the entry point for the MiniJava program.

Compiler Features

The MiniJava compiler is implemented using JavaCC and JTB tools. It consists of several visitors that perform different tasks:

1. Parser: The MiniJava source code is parsed using the BNF grammar (minijava.jj) to construct an Abstract Syntax Tree (AST).

2. Semantic Analysis: The AST is traversed by the TypeCheckVisitor to perform static semantic analysis, ensuring that the program adheres to the MiniJava language rules.

3. Intermediate Representation (IR) Generation: The IRGenVisitor generates LLVM intermediate representation (IR) code for further compilation.

How to Compile and Execute

To compile the MiniJava compiler and execute the examples, follow these steps:

1. Use the provided Makefile to compile the MiniJava compiler:

   make

2. Run the MiniJava compiler on a specific file or a folder containing MiniJava files:

   make execute FILE=path/to/your_file.java

   or

   make execute DIR=path/to/your_folder

   The compiled LLVM IR files for each MiniJava source file will be generated in the same folder with .ll extensions.

3. You can then use Clang or another LLVM-based compiler to compile the generated IR code into an executable:

   clang -o output_file out1.ll

   Finally, execute the output file:

   ./output_file

MiniJava Examples

The minijava-examples/passed folder contains MiniJava example files that should compile successfully. The minijava-examples/errors folder contains files that are expected to throw errors during compilation due to semantic issues.

Please note that this is a simplified version of the MiniJava compiler, and it may not cover all edge cases and features of the full Java language.