C-Mini-Compiler

Compiler Design Lab Project, PES University

Implement the front end of the compiler for C language using Lex and Yacc for the following constructs :

1. Structs
2. Ternary Operators
3. For Loops

How to run

Clone this repository and execute sh run.sh. After execution of various phases of the compiler you may use sh clean.sh to remove output files.

Project details

Following output files are generated upon execution of run.sh :

1. Symbol Table : ./SymbolTable < filename
   Symbol table contains keywords and identifiers, their datatypes and values with some preliminary evaluation of simple expressions. The output of this file will be in symbol_table.txt and the errors while creating the symbol table are stored in errors.txt. The errors handled by the symbol table are

• Undeclared variables
• Multiple declarations of a variable within the same scope
• Invalid value for given datatype

2. Abstract Syntax Tree : ./AST < filename
   Uses graph.c and header.h to display the abstract syntax tree.

3. Intermediate Code Generation : ./ICG < filename
   Generates an if-goto form of intermediate representation of code in output_file.txt. Handles nested for loops, nested ternary operators too.

4. Code Optimization : python3 optimize.py or python3 optimize.py filename
   Requires if-goto form of intermediate representation of code as input. If filename is not specified, it takes the intermediate code from output_file.txt by default.
   Following code optimizations were performed

• Dead code elimination
• Constant folding

References

1. Grammar for C in Lex and Yacc
2. Tutorial (Lex and Yacc) and code for drawing abstract syntax tree