Compiler Construction Compiler Construction Semantic Analysis I.
CS453 Compiler Construction
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Transcript of CS453 Compiler Construction
CS453 Lecture Introduction 1
CS453 Compiler Construction
Original Design: Michelle Strout
Instructor: Wim Bohm
[email protected], [email protected]
Computer Science Building 344
Office hour: Monday 1-2pm
TA: Andy Stone
[email protected], [email protected]
URL: http://www.cs.colostate.edu/~cs453
Send around sheet to collect email addresses and CS linux account names.
Course Logistics (Highlights, see web page for more detail)
Progress Page and Home/News
Read both of these daily.
Syllabus and Grading
Professional Conduct
Do your own work.
Act like a professional in the lab.
Participate
Come to class and recitation.
Come to lab and office hours.
Provide anonymous feedback online.
CS453 Lecture Introduction 2
CS453 Lecture Introduction 3
Plan for Today
Course Logistics
A scanner/parser/interpreter for a simple expression language What is the difference between a compiler and an interpreter?
Compilers class and reality– Why study compilers?
Interpreter and Compiler Structure, or Software Architecture
Overview of Programming Assignments– The MeggyJava compiler we will be building.
CS453 Lecture Introduction 4
Structure of a Typical Compiler
“sentences”
Synthesis
optimization
code generation
target language
IR
IR code generation
IR
Analysis
character stream
lexical analysis
“words”tokens
semantic analysis
syntactic analysis
AST
annotated AST
interpreter
CS453 Lecture Introduction 5
Simple example: Expression Interpreter
character stream (print 2+3*4; …)
lexical analysis
tokens
syntactic analysisplus
calls to evaluate andprint
scanner
parser plusinterpreter
text (14,)
Expression Language: tokens
Tokens: keyword(s): “print” operators/delimiters: “+”, ”-”, “*”, “;” integer literals: “0”, “1”, “2” ,…,”10”, “11”, … , “100”, …
Symbols (Tokens+optional value) are formed by a scanner performing lexical analysis, while reading from a character stream eg: PRINT token+null, SEMI token+null, NUMBER token + Integer-value
Valid tokens are defined by regular expressions, e.g.:
NUMBER: [0-9]+ CS453 Lecture Introduction 6
Expression Language: sentences
Sentences: Program sentences (statements here) are recognized by a parser.
Valid programs are defined by a Grammar:
Program::= stmts
stmts::= stmts stmt | <empty>
stmt::= PRINT exp SEMI
exp::= exp + exp | exp – exp | exp * exp | NUMBER
In our case, the parser evaluates the expressions and prints their
values, i.e. the parser interprets the language
In this week’s recitation you will be exercising with this language, and use tools to generate a scanner and a parser / interpreter
CS453 Lecture Introduction 7
A LOT OF CONCEPTS, TOOLS, and CODE
Compilers are large and complex software structures In this course you will learn a lot of concepts Regular and Context Free grammars, visitor pattern, architecture In this course you will use A LOT of tools Scanner generators and Parser Generators (recitation this week) Eclipse + version control Makefiles jar files assemblers (Meggy) hardware In this course you will write a lot of code 1000s of lines
Don’t get behind! It will be hard, if not impossible, to catch up.
CS453 Lecture Introduction 8
CS453 Lecture Introduction 9
Example MeggyJava program
MeggyJava: a Java subset for the Meggy toy we are playing with in this course. Example code:
import meggy.Meggy;
class PA3Flower {public static void main(String[] whatever){
{ // Upper left petal, clockwise Meggy.setPixel( (byte)1, (byte)1, Meggy.Color.WHITE ); Meggy.setPixel( (byte)2, (byte)1, Meggy.Color.WHITE ); … }}
CS453 Lecture Introduction 10
Structure of the MeggyJava Compiler
“sentences”
SynthesisAnalysis
character stream
lexical analysis
“words”tokens
semantic analysis
syntactic analysis
AST
AST and symbol table
code gen
Atmel assembly code
PA1: Write test cases in C++ and MeggyJava, and Atmel warmupPA2: MeggyJava scannerPA3: setPixel compiler (no AST/ symtab)PA4: add control flow (AST/symtab)PA5: add methods (calls)PA6: add variables and objectsPA7: add arrays