TinyC — A Compiler for a Subset of C (Compilers Laboratory, IIT KGP, Autumn 2024)

This repository contains my implementations for the Compilers Laboratory (CS39003) course at IIT Kharagpur, Autumn 2024.
The project involves building a compiler for TinyC, a carefully selected subset of the C programming language, following a multi-phase approach.

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📂 List of Assignments

Part 1 — Lexer for TinyC

• Goal: Implement the lexical analyzer for TinyC.
• Tools: Flex
• Scope:
  • Based on the ISO/IEC 9899:1999 (C99) standard, but reduced to a subset.
  • Handles keywords, identifiers, constants, string literals, punctuators, and comments.
  • Maintains a symbol table with token names and lexemes.
• Deliverables:
  • Flex specification (.l file)
  • Test input file covering all lexical rules
  • Output: Stream of tokens (<tokenname, lexeme>) and symbol table.

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Part 2 — Parser for TinyC

• Goal: Implement the parser and construct the parse tree for TinyC.
• Tools: Bison + Flex
• Scope:
  • Uses phase structure grammar (subset of C99).
  • Supports expressions, declarations, statements, and external definitions.
  • Parse tree is constructed and stored in a human-readable format.
• Deliverables:
  • Bison specification (.y file) defining grammar and tokens
  • Main driver program to connect lexer and parser
  • Makefile to build lexer and parser
  • Test input program and corresponding parse tree output.

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Part 3 — Machine-Independent Code Generator

• Goal: Generate 3-address code (intermediate representation) for TinyC.
• Tools: Bison + Flex + C++
• Scope:
  • Extends lexer and parser with semantic actions.
  • Generates:
    • 3-address quads
    • Symbol tables (including nested scopes)
    • Auxiliary data structures for translation
  • Supports:
    • Arithmetic, logical, relational, shift, and assignment expressions
    • Simple variable, pointer, array, and function declarations
    • Core statements (selection, iteration, return)
    • Function definitions
  • Excludes complex constructs like switch, goto, compound assignment operators, etc.
• Design Highlights:
  • Symbol Table: Nested, supports lookup, insert, update, and print.
  • Quad Array: Stores intermediate 3-address instructions.
  • Global Functions: makelist, merge, backpatch, typecheck, and type conversion utilities.
• Deliverables:
  • Complete translator (.l, .y, .h, .cxx)
  • Test inputs and corresponding quad outputs
  • Makefile and final tar archive.

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