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CS453 Compiler Construction Instructor: Wim Bohm - - PowerPoint PPT Presentation
CS453 Compiler Construction Instructor: Wim Bohm - - PowerPoint PPT Presentation
CS453 Compiler Construction Instructor: Wim Bohm bohm@cs.colostate.edu Computer Science Building 470 TA: tba tba @cs.colostate.edu URL: http://www.cs.colostate.edu/~cs453 CS453 Lecture Introduction 1 Course Logistics (Highlights, see web
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CS453 Lecture Introduction 3
Plan for Today
Course Logistics (done) Interpreter and Compiler Structure, or Software Architecture 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?
Overview of Programming Assignments
– The MeggyJava compiler we will be building.
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CS453 Lecture Introduction 4
Structure of a Typical Compiler
“sentences” Synthesis
- ptimization
code generation target language IR IR code generation IR Analysis character stream lexical analysis “words” tokens semantic analysis syntactic analysis AST annotated AST interpreter
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Expression Language: tokens Tokens:
keyword(s): “print”
- perators/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]+
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Simple example: Expression Interpreter
character stream (print 2+3*4; …) lexical analysis tokens syntactic analysis plus calls to evaluate and print scanner parser plus interpreter text (14, …)
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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
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Why Compilers?
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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.
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CS453 Lecture Introduction 10
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 ); … … } }
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CS453 Lecture Introduction 11
Structure of the MeggyJava Compiler
“sentences” Synthesis Analysis 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 warmup PA2: MeggyJava scanner and setPixel PA3: add exps and control flow (AST) PA4: add methods (symbol table) PA5: add variables and objects
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