CSE411: Introduction to Compilers

Overview

Jooyong Yi (UNIST)

What is a Compiler?

What is a Compiler?

Source Program →  ································· → Binary

Why do we need a compiler?

Why is not an interpreter enough?

Interpreter Example

import operator

def execute(cmd_seq, stack):
    cmd = cmd_seq[0]
    if isinstance(cmd, int):
        stack.insert(0, cmd)
        cmd_seq.pop(0)
    elif cmd in ['add', 'sub']:
        if not len(stack) >= 2:
            raise Irreducible
        n1 = stack.pop(0)
        if not isinstance(n1, int):
            raise Irreducible
        n2 = stack.pop(0)
        ans = int(operator.__dict__[cmd](n2, n1))

• Consider input: [5, 2, 'add']

Interpreter

• Computation is performed indirectly using software instructions (e.g., the Python arithmetic functions)

|------------------------|
|       Program          |
|------------------------|
|      Interpreter       |
|------------------------|
|       Hardware         |
|------------------------|

Interpreter

• An interpreter typically handles each line of input one by one, and it loses an opportunity for code optimization.

def foo():
    return 1234 * 1234

print(foo() + foo())

Compiler = Translator

Source Program →  ································· → Binary

• A compiler translates a source program into a target program.

Translator

Program in L1 →  ································· → Program in L2

Transpiler = Source-to-Source Compiler

Source Program in Python →  ···························· → Source Program in JavaScript

Source Program in C →  ································· → Source Program in Rust

Basic Questions Regarding Compilers

• How does a compiler work as a whole?
• What are the major components of a compiler?
• How does each component of a compiler work?

Advanced Questions Regarding Compilers

• How can we optimize a program?
• How can we make sure that (source program) ≡ (target program)?
• How can we prove the correctness of compiler optimizations?
• ...

Grading

• Individual assignments: 30%
• Attendance and participation: 30%
• Final exam: 40%

Assignment

• Individual assignments: 30%
  • 4 assignments are planned.
  • Student presentation is planned.
• Attendance and participation: 30%
• Final exam: 40%

Attendance and Participation

• Individual assignments: 30%
• Attendance and participation: 30%
  • More actively participating students will receive higher scores.
• Final exam: 40%

Final Exam

• Paper-based exam

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• Oral exam

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