Compiler Construction 1 Project / Projekat Iz Programskih Prevodioca 1

This project implements a compiler for the imaginary Microjava programming language, designed to translate valid Mikrojava programs into bytecode executable on the Mikrojava Virtual Machine (MJVM). The compiler includes four primary phases:

• lexical analysis
• syntax analysis
• semantic analysis
• code generation.

It is a project on the course Compiler Construction 1 ("Programski Prevodioci 1") on University of Belgrade, Faculty of Electrical Engineering, Module for Computer Engineering and Informatics

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Project Description

The goal is to build a working compiler for Mikrojava, which supports the following functionalities:

1. Lexical Analysis:

   • Processes source code to identify tokens such as identifiers, constants, keywords, operators, and comments.
   • Implemented using the JFlex with .flex specifications.
   • Detects and reports lexical errors with line and column numbers.

2. Syntax Analysis:

   • Verifies if the sequence of tokens forms grammatically correct statements.
   • Builds an Abstract Syntax Tree (AST) for valid programs using the AST-CUP tool.
   • Includes error recovery for certain syntactic issues, allowing continued parsing.

3. Semantic Analysis:

   • Checks the program for contextual errors like type mismatches, undeclared variables, and improper symbol usage.
   • Updates the Symbol Table during analysis.
   • Ensures all semantic rules of Mikrojava are satisfied.

4. Code Generation:

   • Translates syntax and semantically valid programs into bytecode for the MJVM.
   • Produces .obj files that can be executed in the virtual environment.

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Key Features

1. Lexical Analysis

• Detects and processes:
  • Identifiers, numeric and character constants.
  • Keywords (e.g., if, else, while, return).
  • Operators (+, -, *, /, =, etc.).
  • Single-line and multi-line comments.
• Ignores whitespace and formats (e.g., spaces, tabs).
• Reports errors for unrecognized symbols or incomplete constructs.

2. Syntax Analysis

• Implements an LALR(1) grammar for Mikrojava.
• Supports error recovery for common mistakes, such as:
  • Missing semicolons in variable declarations.
  • Incorrect assignment statements.
• Builds and prints the Abstract Syntax Tree (AST) for valid programs.

3. Semantic Analysis

• Updates the Symbol Table during parsing:
  • Tracks global and local variables, constants, arrays, and functions.
  • Checks for proper declaration and usage of all symbols.
• Validates context-sensitive rules, including:
  • Type consistency in expressions and assignments.
  • Correct parameter passing in function calls.

4. Code Generation

• Generates bytecode compatible with MJVM for:
  • Basic arithmetic and logical operations.
  • Array handling (declaration and indexing).
  • Conditional and loop constructs (if, while, for).
  • Input/output operations (read, print).
• Outputs an .obj file, which serves as the executable for MJVM.