Welcome to compilers 131B: static semantic checking and code generation

Read: Chapter 5 (review), Chapter 6 (Thursday and thereafter)

Introduce people
  - self
       + interests in software engineering, compilers, programming languages,
         and parallel computing
       + aikido (martial arts), music, biking, hiking, fine food :)

  - TA's and proctors


The course itself
  - A Compiler is a special case of a Translator
     + Translation from human to machine languages, with eye to optimization
     + How do gcc, g++, javac, etc. work?
     + Also teaches general techniques in translation: parsing web pages,
       e-mail messages, etc.
     + Focus here on "back-end"
        - Static semantic checking (is program consistent?)
        - Code generation to machine language

  - It's not just a lot of coding, but maybe biggest program you've written
      + Integrating and applying all the knowledge from previous classes
        (e.g, C/C++, data structures, automata, systems & assembly programming)
     + Learn about practical aspects of language design and
       computer architecture

  - This is a also course in Engineering: building large, complex systems
      + Design for separation of concerns, reuse (e.g., object-orientation)
      + Making good use of tools to save labor
      + Teamwork: cooperating with other people to complete a large task
      + Avoiding failure through planning (specify, design, and test)
      + Using domain-specific knowledge to simplify system building
        (e.g., parsing theory, software architecture)

  - In other words, this course is part of your preparation for becoming
    the next generation of great programmers, system builders, and engineers
      + You're the top students in California
      + 19th century engineer John Roebling designed the Brooklyn Bridge
         - at 1595.5 feet, the world's longest suspension bridge at the time
         - also arguably the most beautiful bridge, the centerpiece of the NYC
           skyline
      + Software - in baby steps
        - Ken Thompson and Dennis Ritchie - Unix
        - Linus Torvalds - Linux
        - Richard Stallman - GNU utilities
        - Charles Simonyi - MS Word
        - James Gosling and others - Java libraries
      + Behind each of these big names are a superb team of engineers
        - Engineering efforts are by definition the work of many good people
          working cooperatively

Knowledge vs. Skill
  - This is not just a knowledge class (memorization and recall)

  - This is an experience/skill class: practice, failure, and learning from it

  - To get a good grade, you cannot just understand the material

  - You must be able to *apply* it successfully

  - If you are dedicated to this class, you will be successful
     + initial failures inform how to do things better later


Organization, Exams, and Project
  - Everything you need to know is on the web
      + Project info, announcements
      + Notes for this class, also available at Soft Reserves.
        Bring them to class to aid your notetaking.

  - We are available a *lot* of the time
       + E-mail, discussion forum, sun lab, office hours,
       + In a pinch? drop by

  - 50% exams, 50% project

  - Exams: 15% quizzes (8-10 on Tuesdays, drop 2-3 lowest), 35% final
      + Drawn from material covered in lecture
      + Basic knowledge
      + Apply knowledge in new situations

  - Project
      + 2 projects: Static Semantic Checking, Code Generation
         - there will be weekly internal milestones and other techniques to
           ensure steady progress
      + See web site for details, updates
      + Review handout
         - static semantic checking
         - extend symbol table to represent types
         - extend parser to pass around variables/types
         - add actions to parser to manipulate types


A Word on Academic Integrity
  - First, about FAIRNESS: each students should have equal access to
    materials to assist them in the class
      + Your fellow student's grade reflects what he or she knows
      + Your grade reflects what you know
      + Other people doing unfairly well makes you look worse
         - jobs, grad school, etc.
  - Also about competence and ability
      + Employers know what they are getting
      + Can build the software that the student's record promises
      + A huge deal in ``mission critical'' systems
         - from air traffic control to accounting systems
  - Living in the real world
      + Borrowing other people's work is called theft and fraud
      + Lose job, land in jail, ruin company
  - The ground rules for 131B
      + Can only use resources explicitly provided by me and TA's
      + In particular, cannot use or see someone else's Oberson compiler
      + We compare against every compiler developed over last 10 years
  - Penalties can be severe
      + Failure, suspension, explusion
      + Better to withdraw and retake, if necessary
  - Fact: violations often occur in a panic at the last minute
      + Start early
      + Keep your head
  - If you are unsure, ask


Review Remaining Handouts

Break: who needs partner, compiler, account, card signed?