课程名 编译原理 Compiling Techniques

1. 课程名 编译原理Compiling Techniques 浙江大学计算机学院与软件学院 编译原理课程组

2. Information • Instructor • 李莹 • cnliying@zju.edu.cn • 13335880866 • Teacher Assistant • 孙煦雪 • sunxuxue@zju.edu.cn • 15858138880

3. Text Books • The Dragon Book: Compilers Principles, Techniques, & Tools, Second Edition, Alfred V. Aho • The Tiger Book: Modern Compiler Implementation in C, Andrew Appel

4. Grade Distribution • attend class • 10% • Homework • 10% • Class test or Mid-Term Exam • 15% • Final during exam period: • 65%

5. Course Structure • Course has theoretical and practical aspects • CompilingTechniques • Compiler Design

6. Compiler: why? • 1940’s The first electronic computers • Programming in machine language • Slow , tedious and error prone • 1954 IBM develops the 704 • All programming done in assembly • Software costs exceeded hardware costs!

7. Compiler: why? • Emerge of higher-level languages • with higher-level notations • more easily programming • Fortran • Scientific computation • Cobol • Business data processing • Lisp • Symbolic computation

8. Higher-level Language Machine Language For human For machine A compiler Compiler

9. Why Study Compilers • Basic idea for constructing translators. • Principle and Techniques reusable in other CS domains. • Influences hardware design, e.g., RISC, VLIW. • Tools (mostly “optimization”) for enhancing software reliability and security. • Excellent software-engineering example --- theory meets practice. • Essential software tool.

10. A compiler • A compiler is a program that can read a program in one language and translate it into an equivalent program in another language Source Program Compiler Target Program Input Output

11. A Interpreter • An interpreter directly execute the operations of source program on inputs Source program Interpreter Output Input

12. A language-processing system

13. The structure • Two parts of a compiler • Analysis, front end • Synthesis,back end • operate as a sequence of phases

14. Lexical Analysis • Reads stream of characters • Group the characters into lexemes • For each lexemes, output a Token • <token-name, attribute-value>

15. Syntax Analysis • Reads Token stream • Create tree-like intermediate representation (syntax tree) • The grammatical structure of the token stream

16. Semantic Analysis • Uses • syntax tree • information in Symbol table • understand the meaning of program • Too hard for compilers • only check Semantic consistency • Type checking • Type conversions (Coercions)

17. Intermediate Code Geneartion • For portability and reuse • Before generate target program • Generate intermediate representations first • Three address code • Code sequence • One operator • Three operands (max)

18. Code Optimization • To improve the intermediate code • Run faster • Use less memory • Consume less power

19. Code Generation • Takes an intermediate representation as input • Maps it to target language • Registers and memory allocation • Translate IR instructions into machine instructions

20. Symbol-Table Management • An essential function of a compiler • Records • variable names • various attributes of them

21. Passes • Several phases may be grouped into a pass • A pass reads an input file and writes an output file • An example of a pass including: • Lexical analysis, • parsing, • semantic analysis • IR generation.

22. Compiler construction tools-1 • Some tools could be used to help compiler construction • Parser Generators. automatically produce syntax analyzers from a grammatical description of a programming language.Yacc • Scanner Generators. produce lexical analyzers from a regular-expression description of the tokens of a language.Lex • Syntax-directed translation engines. produce collections of routines for walking a parse tree and generating intermediate code.

23. Compiler construction tools-2 • Code-generator generators. produce a code generator from a collection of rules for translating each operation of the intermediate language into the machine language for a target machine. • Data-flow analysis engines. facilitate the gathering of information about how values are transmitted from one part of a program to each other part. • Compiler-construction toolkit. provide an integrated set of routines for constructing various phases of a compiler.

24. The move to Higher-level Languages • First generation languages: machine languages. • Second generation: assembly languages. • Third generation: higher-level languages, Fortran, Cobol, Lisp, C…. • Forth generation: languages designed for specific applications, NOMAD, SQL • Fifth generation: logic- and constraint-based languages, Prolog and OPS5

25. Another classification of languages • Imperative • how a computation is to be done • C, C++, C#, Java • Declarative • what computation is to be done • ML, Haskell, Prolog • Von neumann languages • Object-oriented languages • Scripting languages

26. Impacts on Compilers • Can help promote the use of high-level languages • Compiler writing is challenging. • A compiler must translate correctly the potentially infinite set of programs

27. Application of Compiler Technology • Implementation of higher-level programming languages • Optimizations for computer architectures • Design of new computer architectures • Program translations • Software productivity tools

28. Optimizations for computer architecture • Parallelism • Multi-core, many-core • VLIW (very long instruction word), issue multiple operations in parallel • Memory hierarchies • Several levels of storage • The closer, the faster • Registers, CPU cache • Main memory • disks

29. Design of new computer architecture • RISC • Specialized architecture • VLIW • SIMD

30. Program translation • Binary translation • x86 →Sparc • x86 →arm • Hardware synthesis • VHDL RTL • Database query interpreters • Compiled simulation

31. Software Productivity Tools • Type checking • Bounds Checking • Memory-Management tools • Code generators

32. Summary • Language Processors • Compiler Phases • Machine and Assembly languages • Modeling in Compiler Design • Code Optimization • Higher-level Languages • Compilers and Computer Architecture • Software Productivity and Software Security • Programming Language Basics: Scope Rules, Environments, Block Structure, Parameter Passing, Aliasing

33. The end of Lecture01