Course Webpage for Compilers (P423, P523, E313, and E513)

Indiana University, Fall 2020

High-level programming languages like Racket make it easier to program relative to low-level languages such as x86 assembly code. But how do high-level languages work? There’s a big gap between Racket and machine instructions for modern computers. In this class you learn how to translate Racket programs (a dialect of Scheme) all the way to x86 assembly language.

Traditionally, compiler courses teach one phase of the compiler at a time, such as parsing, semantic analysis, and register allocation. The problem with that approach is it is difficult to understand how the whole compiler fits together and why each phase is designed the way it is. Instead, each week we implement a successively larger subset of the Racket language. The very first subset is a tiny language of integer arithmetic, and by the time we are done the language includes first-class functions.

Prerequisites: B521 or C311. Fluency in Racket is highly recommended as students will do a lot of programming in Racket. Prior knowledge of an assembly language helps, but is not required.

Textbook: The notes for the course are available here. If you have suggestions for improvement, please either send an email to Jeremy or, even better, make edits to a branch of the book and perform a pull request. The book is at the following location on github:

https://github.com/IUCompilerCourse/Essentials-of-Compilation

Lecture: Tuesday and Thursday, 3:15pm to 4:30pm, on Zoom Meeting ID 950 3713 8921. (See the Piazza announcement for the password.)

Lecture Notes and Recordings:

• August 25 Notes, Video: Introduction, Concrete and Abstract Syntax, Racket Structures, Grammars,

• August 27 Notes, Video: Interpreters, Compiler Correctness, R1 Language, x86

• September 1 Notes, Video: Uniquify, Remove Complex Operands, Explicate Control

• September 3 Notes, Video: Select Instructions, Assign Homes, Path Instructions, Print x86

• September 8 Notes, Video: Code review of compiling integers and variables.

• September 10 Notes, Video: Register Allocation (Liveness Analysis, Build Interference Graph)

• September 15 Notes, Video: Register Allocation (Graph Coloring)

• September 17 Notes, Video: Booleans and Control Flow

• September 22 Notes, Video: Code review of register allocation.

• September 24 Notes, Video: More x86, Explicate Control with Branching.

• September 29 Notes, Video: Impact of branching on instruction selection and register allocation. Challenge: optmizing and removing jumps.

• October 1 Notes, Video: Garbage Collection: 2-space Copy Collector

• October 6 Notes, Video: Code review of booleans and control flow

• October 8 Notes, Video: Tuples and Garbage Collection: the Compiler Passes

• October 13 Notes, Video: Functions and Efficient Tail Calls

• October 15 Notes, Video: Compiling Functions, the Passes

• October 20 Notes, Video: Compiling Functions, Examples, Start of Lambda

• October 22 Notes, Video: Lambdas and Closure Conversion

• October 27 Notes, Video: Code Review of Tuple & Garbage Collection

• October 29 Notes, Video: Closure Conversion, The Compiler Pass

• November 3 Notes, Video: Dynamic Typing

• November 5 Notes, Video: Dynamic Typing, continued

• November 10 Notes, Video: Code Review of Functions

• November 12 Notes, Video: Optimizing Closures

• November 17 Notes, Video: Dataflow Analysis

• November 19 Notes, Video: Compiling Loops and Liveness Analysis via Dataflow

• December 1 Notes, Video: Assignment and Begin

• December 3: Review of Dynamic Typing (see notes for Nov. 3 and 5)

• December 8 Notes, Video: Code Review of Compiling Lambda

• December 10 Notes, Video: Review of Compiling Functions

Office hours

• Jeremy Siek (jsiek): Tuesdays and Thursdays 4:30-5:30pm. Zoom Meeting ID: 949 1594 8290.

• Caner Derici (cderici): Mondays 11am-12pm, Wednesdays 11am-12pm. Zoom Meeting ID: 774 5516 2736.

Topics:

• Instruction Selection

• Register Allocation

• Static type checking

• Conditional control flow

• Mutable data

• Garbage collection

• Procedures and calling conventions

• First-class functions and closure conversion

• Dynamic typing

• Generics

• High-level optimization (inlining, constant folding, copy propagation, etc.)

Grading:

Course grades are based on the following items. For the weighting, see the Canvas panel on the right-hand side of this web page. Grading will take into account any technology problems that arrise, i.e., you won’t fail the class because your internet went out.

• Assignments
• Quizzes
• Midterm Exam (October 23, Online as a Canvas Quiz)
• Final Exam (December 15, Online as a Canvas Quiz)

Assignments:

Organize into teams of 2-4 students. Assignments will be due bi-weekly on Mondays at 11:59pm. Teams that include one or more graduate students are required to complete the challenge exercises.

Assignment descriptions are posted on Canvas. Turn in your assignments by creating a github repository and giving access to Jeremy (jsiek) and Caner (cderici).

Assignments will be graded based on how many test cases they succeed on. Partial credit will be given for each “pass” of the compiler. Some of the tests are in the public support code (see Resources below) and the rest of the tests will be made available on Sunday night, one day prior to the due date. The testing will be done on the linux machine kj.luddy.indiana.edu named after Katherine Johnson of NASA fame. The testing will include both new tests and all of the tests from prior assignments.

You may request feedback on your assignments prior to the due date. Just commit your work to github and send us email.

Students are responsible for understanding the entire assignment and all of the code that their team produces. The midterm and final exam are designed to test a student’s understanding of the assignments.

Students are free to discuss and get help on the assignments from anyone or anywhere. When posting questions on Piazza, it is OK to post your code.

In contrast, for quizzes and exams, students are asked to work alone. The quizzes and exams are closed book. We will be using Respondus Monitor for online proctoring.

The Final Project is due Dec. 4 and may be turned in late up to Dec. 11.

Late assignment policy: Assignments may be turned in up to one week late with a penalty of 10%.

Email Discussion Group: on Piazza

Slack Chat/Messaging: Workspace (see invitation link on Piazza or signup using your iu email address).

Resources:

• Github repository for support code and test suites is here
• Racket
• Racket Documentation
• Notes on x86-64 programming
• x86-64 Machine-Level Programming
• Intel x86 Manual
• System V Application Binary Interface
• Uniprocessor Garbage Collection Techniques by Wilson.
• Fast and Effective Procedure Inlining by Waddell and Dybvig.

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1) email biasincident@indiana.edu or incident@indiana.edu;

2) call the Dean of Students Office at (812) 855-8188 or

3) use the IU mobile App (m.iu.edu). Reports can be made anonymously.

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The Dean of Students office provides support for students dealing with serious or emergency situations after 5 p.m. in which an immediate response is needed and which cannot wait until the next business day. Faculty or staff who are concerned about a student’s welfare should feel free to call the Dean on Call at (812) 856-7774. This number is not to be given to students or families but is for internal campus use only. If someone is in immediate danger or experiencing an emergency, call 911.

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Sexual Misconduct.

As your instructor, one of my responsibilities is to create a positive learning environment for all students. Title IX and IU’s Sexual Misconduct Policy prohibit sexual misconduct in any form, including sexual harassment, sexual assault, stalking, and dating and domestic violence. If you have experienced sexual misconduct, or know someone who has, the University can help.

If you are seeking help and would like to speak to someone confidentially, you can make an appointment with:

• The Sexual Assault Crisis Services (SACS) at (812) 855-8900 (counseling services)

• Confidential Victim Advocates (CVA) at (812) 856-2469 (advocacy and advice services)

• IU Health Center at (812) 855-4011 (health and medical services)

It is also important that you know that Title IX and University policy require me to share any information brought to my attention about potential sexual misconduct, with the campus Deputy Title IX Coordinator or IU’s Title IX Coordinator. In that event, those individuals will work to ensure that appropriate measures are taken and resources are made available. Protecting student privacy is of utmost concern, and information will only be shared with those that need to know to ensure the University can respond and assist. I encourage you to visit stopsexualviolence.iu.edu to learn more.