UVM CS202: Compiler Construction (Spring 2021)



Course Description

This course covers the design and construction of compilers. You’ll learn how to translate a high-level, garbage-collected programming language all the way into Intel x86 assembly language.

Instead of learning about each phase of the compilation process sequentially, we’ll start by compiling a tiny subset of the target language directly into assembly code. Each week, we’ll add a new feature to our language, and learn about all the phases needed to compile that feature into assembly. At each step, you’ll have a functioning compiler that can run real code; by the end of the course, your compiler will work on a realistic programming language including first-class functions.

Topics covered include:

This course will be structured around lectures and a weekly programming assignment. Each lecture will cover a new language feature and the techniques needed to compile it; in the corresponding programming assignment, you will implement support for the new feature in your own compiler. Students should expect to spend 6-8 hours per week outside of class on the weekly programming assignments. The required materials for this course are all freely available online.

Students will also complete a final project, in which they extend their compiler with an additional significant language feature of their choice.

Graduate students are expected to complete additional challenge exercises included in each assignment, and to select more ambitious final projects compared to undergraduate students.

This course is primarily intended for computer science students, but may also be appropriate for some graduate students in other areas with an interest in programming languages and strong programming experience.

Prerequisites: CS124 and CS125

Text and Resources

Please do not buy any books for this course. All required reference material is available online for free.

The primary textbook we will use for this course is:

Other course resources:

Additional/fun resources:



Your grade for the course will be determined as follows:

Your final grade will be determined by summing the total number of points awarded and calculating the percentage of the total possible points. This percentage is translated into a letter grade as follows:

Undergraduate Students

Percent Letter Grade
98-100 A+
93-97 A
90-92 A-
87-89 B+
83-86 B
80-82 B-
77-79 C+
73-76 C
70-72 C-
67-69 D+
63-66 D
60-62 D-
<60 F

Graduate Students

Percent Letter Grade
98-100 A+
93-97 A
90-92 A-
87-89 B+
83-86 B
80-82 B-
77-79 C+
73-76 C
70-72 C-
<70 F


Assignments will generally be due weekly on Mondays at 11:59pm, with breaks for the midterm exam and final project. Your assignment will be graded using a test suite which will be made available one day before the assignment due date.

Late assignments will not be accepted. Each assignment builds extensively on the last one, and mastering the assignment material is crucial to success in this course. If you fall behind on completing the assignments, it will be extremely difficult to catch up.

Therefore, on Wednesday after each assignment due date, we will discuss that assignment’s solution in lecture, and the complete solution will be made available on Blackboard. I encourage students to take advantage of the official solutions to avoid falling behind.

Partial credit will be (extensively) given on assignments. I encourage you to submit something for every assignment, even if your solution is far from complete.

Most assignments include a challenge exercise, which generally involves extending your compiler with extra features or optimization capabilities. Graduate students are required to complete all of the challenge exercises, and the challenge exercise will account for 20% of the total grade for the assignment. Undergraduates who successfully complete the challenge exercise for an assignment will receive 5% extra credit for that assignment.

Assignments will be graded according to the following rubric:

Grade Assignment Status
100 Passes all test cases
95 Passes 75% of test cases
90 Passes 50% of test cases
85 Passes at least 1 test case
80 Project compiles; all passes appear to be nearly complete
75 All or nearly all passes appear nearly complete
70 Significant work on all passes
65 Significant work on at least 75% of the passes
60 Significant work on at least half of the passes
<60 Missing passes

In-Class Exercise

An in-class exercise will be due every Friday at 11:59pm. The exercises for the week will be released on Monday morning, and we will complete these exercises together during the lectures each week. If you attend lectures and follow along, the in-class exercises should not require significant additional time outside of lecture to complete.


There will be no exams.

Final Projects

Each student will select and complete a new language feature for their compiler. Final project deliverables will consist of a short project proposal, a compiler implementing the selected language feature, and test cases demonstrating its use. Final projects may be completed in teams of up to 3 students; larger teams will be expected to complete more ambitious projects.

Graduate Students

Graduate students will be expected to complete additional requirements in order to receive graduate credit for this course:

Collaboration & Allowed References

Collaboration on the high-level ideas and approach on assignments is encouraged. Copying someone else’s work (outside of your team members) is not allowed.

The official references for the course are listed in the schedule below. Copying from references other than these is not allowed. In particular, code should not be copied from other sources, including Stack Overflow and other public sources.

Students caught copying work are eligible for immediate failure of the course and disciplinary action by the University. All academic integrity misconduct will be treated according to UVM’s Code of Academic Integrity.

Guest Lectures & Extra Credit

During the semester there will be ~5 guest lectures from visiting faculty on MS Teams. I will give 0.5% extra credit towards your final grade for each of these lectures that you attend. To receive extra credit, you must take notes in person during the lecture, and then e-mail me your notes after the talk. The guest lectures will take place at 12-1pm on the following dates:


Assignment Topics Covered Text Chapter Due Date
1 Compiling R0 to x86 Chapter 1 & 2 Feb 8, 11:59pm
2 Compiling RVar to x86 Chapter 2 Feb 22, 11:59pm
3 Register Allocation Chapter 3 Mar 8, 11:59pm
4 Booleans and Control Flow (RIf) Chapter 4 Mar 22, 11:59pm
5 Vectors and Garbage Collection (Rvec) Chapter 5 Apr 14, 11:59pm
6 Compiling Functions (Rfun) Chapter 6 May 4, 11:59pm
  Final Project   See below

Class Schedule

Note: no class on Wednesday, March 24

Week of Topic Assignment
Feb 1 ASTs, Interpreters, x86 Assembly, Compiling R0  
Feb 8 Compiling RInt A1 Due (Monday)
Feb 15 Compiling RInt  
Feb 22 Register allocation A2 Due (Monday)
Mar 1 Register allocation  
Mar 8 Booleans & Typechecking A3 Due (Monday)
Mar 15 Compiling RIf  
Mar 22 Intermission A4 Due (Monday)
Mar 29 Vectors & Garbage collection I  
Apr 5 Vectors & Garbage collection II  
Apr 12 Compiling functions I A5 Due (Wednesday)
Apr 19 Compiling functions II  
Apr 26 Compiling first-class functions  
May 3 Dynamic typing & objects A6 Due (Tuesday)
May 10 Optimization; binary & instruction sets  

Final Projects

Suggested Project Ideas

For each of these project ideas, a parser and lecture video will be provided.

Records (Simple Object System)

Extend the vectors present in RFun to records with named fields. Record types are sufficient to implement a simple object system, in which an object’s methods are stored as functions in record fields. There is no chapter in the textbook describing this extension, but a parser and compiler template will be provided, as well as a lecture video.


record Point {
  add: (Point, Point) -> Point,
  x: Integer,
  y: Integer

def addPoint(self: Point, other: Point): Point = {
  Point(self.add, self.x + other.x, other.x + other.y)

let p1 = Point(addPoint, 1, 2) in
let p2 = Point(addPoint, 3, 4) in
p1.add(p1, p2)

Anonymous (Lexically-scoped) Functions

Extend the RFun language to support anonmyous functions (i.e. “lambda” functions), as described in chapter 7 of the textbook. Your anonymous functions should be lexically scoped. A parser, compiler template, and lecture video will be provided.


let x = 5 in
let f = lambda y: Integer -> x + y
in f(6)

Dynamic Typing

Extend the RFun language to support dynamic typing as described in chapter 8 of the textbook. A parser, compiler template, and lecture video will be provided.


42 == (if 5 == 5 then 42 else True)

Other Project Ideas

More complicated:

Very tough:


The goal of the final project is for you to design and implement your own compiler extension. Final projects will be completed in groups of 1-3. The deliverables for the project will be as follows:

Schedule & Grading

The final project is worth 14% of your final grade. The schedule for final project deliverables, and the contribution of each one to the grade you receive for the final project, are as follows:

Deliverable Due Date Grade Percent Turn In
Project Proposal Friday, May 7 at 11:59pm 10% Blackboard
Implementation & README Monday, May 17 at 11:59pm 50% Blackboard
Project Presentations Monday, May 17 at 11:59pm 30% Blackboard