Simple Compiler

Overview

This project implements a simple compiler that processes C-like language source code and generates x86 assembly code. The compiler is developed using Flex (Lexical Analysis) and Bison (Syntax Analysis), with a backend generating assembly code and supporting execution through NASM.

Features

• Lexical Analysis: Uses Flex to tokenize source code (keywords, operators, identifiers, etc.).
• Syntax Analysis: Implements Bison-based parsing for parsing grammar rules.
• Intermediate Code Generation: Converts parsed structures into stack-based intermediate representations.
• Code Execution Simulation: Simulates stack-based execution before generating final machine code.
• Assembly Code Generation: Translates intermediate representations into x86 NASM assembly.
• Custom I/O Handling: Implements low-level I/O functions for interacting with the generated program.

File Structure

|-- input_file/        # Folder containing input C-like source files
|   |-- test.c         # Example input file
|
|-- output_file/       # Folder containing generated outputs
|   |-- test.asm       # Generated assembly file
|   |-- test.o         # Compiled object file
|   |-- test           # Final executable file
|
|-- src/               # Source code of the compiler
|   |-- display_lex_result  # Executable for displaying lexer results
|   |-- io_tool.c      # Custom I/O functions using x86 inline assembly
|   |-- lex_anal.l     # Flex lexical analyzer definition
|   |-- macro.inc      # NASM macros for generating x86 assembly
|   |-- my_gcc         # Compilation script for generating executable files
|   |-- syn_anal.y     # Bison syntax analyzer (parsing rules)
|
|-- README.txt         # Project documentation

Installation & Usage

Prerequisites

Ensure you have the following installed on your system:

• Flex (for lexical analysis)
• Bison (for syntax analysis)
• GCC (for compiling the front-end)
• NASM (for assembling the final code)

Compilation Steps

1. Lexical & Syntax Analysis

flex src/lex_anal.l
bison -vdty src/syn_anal.y
gcc -o src/front_end src/lex.yy.c src/y.tab.c

2. Intermediate Code Simulation (Optional Debugging Step)

./src/front_end input_file/test.c

3. Assembly Code Generation & Linking

./src/my_gcc input_file/test.c

4. Execution

./output_file/test

Example

Input (Source Code)

int main() {
    int a = 5;
    int b = 10;
    int c = a + b;
    print("Sum: %d", c);
    return 0;
}

Generated Assembly (Excerpt)

push 5
pop a
push 10
pop b
push a
push b
add
pop c
push c
call print

Contributors

• Haoqing Liu

License

This project is licensed under the MIT License.