Language processing tools

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Compilers and Language Processing Tools

Summer Term 2013

Arnd Poetzsch-Heffter Annette Bieniusa

Software Technology Group TU Kaiserslautern

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Content of Lecture

1. Introduction

2. Syntax and Type Analysis 2.1 Lexical Analysis

2.2 Context-Free Syntax Analysis

2.3 Context-Dependent Analysis (Semantic Analysis) 3. Translation to Intermediate Representation

3.1 Languages for Intermediate Representation 3.2 Translation of Imperative Language Constructs 3.3 Translation of Object-Oriented Language Constructs 3.4 Translation of Procedures

4. Optimization and Code Generation 4.1 Assembly and Machine Code 4.2 Optimization

4.3 Register Allocation 4.4 Further Aspects

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Content of Lecture (2)

5. Selected Topics in Compiler Construction 5.1 Garbage Collection

5.2 Just-in-time Compilation

5.3 XML Processing (DOM, SAX, XSLT)

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Outline

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Overview and Motivation Language Processing Tools

Language processing tools

• Processing of source texts in (source) languages

• Analysis of (source) texts

• Translation to target languages

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Language processing tools (2)

Typical source languages

• Programming languages: C, C++, C#, Java, Scala, Haskell, ML, Smalltalk, Prolog

• Script languages: JavaScript, bash

• Languages for configuration management: make, ant, maven

• Domain-, application-, and tool-specific languages: BPEL, Excel, JFlex, CUPS,

• Specification languages: Z, CASL, Isabelle/HOL, JML

• Formatting and data description languages: LaTeX, HTML, XML

• Design and architecture description languages: UML, SDL, VHDL, Verilog, ABS

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Language processing tools (3)

Typical target languages

• Assembly, machine, and bytecode languages

• Programming languages

• Data and layout description languages

• Languages for printer control

• ...

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Language processing tools (4)

Language implementation tasks

• Tool support for language processing

• Integration into existing systems

• Connection to other systems

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Overview and Motivation Application Domains

Application domains

• Programming environments (IDE)

I Context-sensitive editors, class browers

I Graphical programming tools

I Pre-processors

I Compilers

I Interpreters

I Debuggers

I Run-time environments (loading, linking, execution, memory management e.g. JVM, .NET)

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Application domains (2)

• Generation of programs from models (e.g. UML)

• Program comprehension, re-engineering

• Design and implementation of domain-specific languages

I Robot control

I Simulation tools

I Spread sheets, active documents

• Web technology

I Analysis of Web sites

I Active Web sites (with integrated functionality)

I Optimization of caching

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Related fields

• Formal languages, language specification and design

• Programming and specification languages

• Programming, software engineering, software generation, software architecture

• System software, computer architecture

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Overview and Motivation Tasks of Language Processing Tools

Tasks of Language-Processing Tools

Analyser Translation Interpreter Source Code Source Code

Target Code Analysis

Results

Source Code

Input Data

Output Data

Analysis, translation and interpretation are often combined.

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Tasks of Language-Processing Tools (2)

1. Translation

I Compiler implements analysis and translation

I OS and real machine implement interpretation Pros:

I Most efficient solution

I One interpreter for different programming languages

I Prerequisite for other solutions

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Tasks of Language-Processing Tools (3)

2. Direct interpretation

I Interpreter implements all tasks.

I Examples: JavaScript, command line languages (bash)

I Pros: No translation necessary (but analysis at run-time)

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Tasks of Language-Processing Tools (4)

3. Abstract and virtual machines

I Compiler implements analysis and translation to abstract machine code

I Abstract machine works as interpreter

I Examples: Java/JVM, C#, .NET

I Pros:

• Platform independent (portability, mobile code)

• Self-modifing programs possible

4. Other combinations

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Overview and Motivation Examples

Example: Analysis

package b1_1

;

class Weltklasse extends Superklasse implement BesteBohnen {Qualifikation studieren ( Arbeit schweiss) { return new

Qualifikation ();}}

Beispiel: (Analyse)

javac-Analysator

Superklasse.class Qualifikation.class Arbeit.class

BesteBohnen.class

...

b1_1/Weltklasse.java:4: '{' expected.

extends Superklasse

^ 1 error

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Example: Translation

17.04.2007 © A. Poetzsch-Heffter, TU Kaiserslautern 9 package b1_1;

class Weltklasse extends Superklasse implements BesteBohnen {

Qualifikation studieren ( Arbeit schweiss ) { return new Qualifikation();

}}

Beispiel 1: (Übersetzung)

javac

Superklasse.class Qualifikation.class Arbeit.class

BesteBohnen.class

...

Compiled from Weltklasse.java class b1_1/Weltklasse

extends ... implements ... { b1_1/Weltklasse();

b1_1.Qualifikation studieren(...);

}

Method b1_1/Weltklasse() ...

Method b1_1.Qualifikation studieren(...) ...

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Example: Translation (2)

Result of translation_17.

04.2007© A. Poetzsch-Heffter, TU Kaiserslautern Beispiel 1:(Fortsetzung)

Compiled from Weltklasse.java class b1_1/Weltklasse

extends b1_1.Superklasse implements b1_1.BesteBohnen { b1_1/Weltklasse();

b1_1.Qualifikation studieren(b1_1.Arbeit);

}

Method b1_1/Weltklasse() 0 aload_0

1 invokespecial #6 <Method b1_1.Superklasse()>

4 return

Method b1_1.Qualifikation studieren(b1_1.Arbeit) 0 new #2 <Class b1_1.Qualifikation>

3 dup

4 invokespecial #5 <Method b1_1.Qualifikation()>

7 areturn

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Example 2: Translation

17.04.2007 © A. Poetzsch-Heffter, TU Kaiserslautern 11 int main() {

printf("Willkommen zur Vorlesung!");

return 0;

}

gcc

.file "hello_world.c"

.version "01.01"

gcc2_compiled.:

.section .rodata .LC0:

.string "Willkommen zur Vorlesung!"

.text .align 16 .globl main

.type main,@function main:

pushl %ebp movl %esp,%ebp subl $8,%esp ...

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Example 2: Translation (2)

Result of translation

Beispiel 2: (Fortsetzung)

.file "hello_world.c"

.version "01.01"

gcc2_compiled.:

.section .rodata .LC0:

.string "Willkommen zur Vorlesung!"

.text .align 16 .globl main

.type main,@function main:

pushl %ebp movl %esp,%ebp subl $8,%esp addl $-12,%esp pushl $.LC0 call printf addl $16,%esp xorl %eax,%eax jmp .L2 .p2align 4,,7 .L2:

movl %ebp,%esp popl %ebp ret .Lfe1:

.size main,.Lfe1-main

.ident "GCC: (GNU) 2.95.2 19991024 (release)"

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Example 3: Translation

17.04.2007 © A. Poetzsch-Heffter, TU Kaiserslautern 13

\documentclass{article}

\begin{document}

\vspace*{7cm}

\centerline{\Huge\bf It‘s groovy}

\end{document}

groovy.tex (104 bytes)

...

groovy.dvi (207 bytes, binary)

%!PS-Adobe-2.0

%%Creator: dvips(k) 5.86 ...

%%Title: groovy.dvi ...

groovy.ps (7136 bytes)

latex

dvips

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Example: Interpretation

Beispiel: (Interpretation)

...

14 iload_1 15 iload_2 16 idiv 17 istore_3 ...

.class-Datei

Eingabedaten

Ausgabedaten ...

14 iload_1 15 iload_2 16 idiv 17 istore_3 ...

Java Virtual Machine (JVM)

Input Data

Output Data .class File

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Example: Combined technique

Java implementation with just-in-time (JIT) compiler

17.04.2007 © A. Poetzsch-Heffter, TU Kaiserslautern 15

Kombinierte Implementierungstechnik:

Java-Implementierung mit JIT-Übersetzer

Java-Überset- zungseinheit

javac

Analysator Übersetzer

Eingabedaten

Java Byte Code .class-Datei

Ausgabedaten JIT-Übersetzer

JVM

Maschinencode reale Maschine/Hardware (JIT=Just in time) Beispiel: (Kombinierte Technik)

Java Source Code Unit

Analyzer Translator

Input Data

Output Data .class file

JIT Translator

Machine Code Real Machine / Hardware

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Language Processing Terminology and Requirements

Language processing: The task of translation

Translator Source Code

Error Message or Target Code

• Translator(in a broader sense):

Analysis, optimization and translation

• Source code:

Input (string) for translator in syntax of source language (SL)

• Target Code:

Output (string) of translator in syntax of target language (TL)

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Phases of language processing

• Analysis of input:

I Program text

I Specification

I Diagrams

• Dependant on target of implementation

I Transformation (XSLT, refactoring)

I Pretty printing, formatting

I Semantic analysis (program comprehension)

I Optimization

I (Actual) translation

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Compile time vs. run-time

• Compile time: during run-time of compiler/translator Static: All information/aspects known at compile time, e.g.:

I Type checks

I Evaluation of constant expressions

I Relative addresses

• Run-time: during run-time of compiled program

Dynamic: All information that are not statically known, e.g.:

I Allocation of dynamic arrays

I Bounds check of arrays

I Dynamic binding of methods

I Memory management of recursive procedures

Fordynamic aspectsthat cannot be handled atcompile time, the compiler generates code that handles these aspects atrun-time.

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What is a good compiler?

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Requirements for translators

• Error handling (static/dynamic)

• Efficient target code

• Choice: Fast translation with slow code vs. slow translation with fast code

• Semantically correct translation

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Semantically correct translation

Intuitive definition: Compiled program behaves according to language definition of source language.

Formal definition:

• semSL: SL_Program×SL_Data→SL_Data

• semTL: TL_Program×TL_Data→TL_Data

• compile: SL_Program→TL_Program

• code: SL_Data→TL_Data

• decode: TL_Data→SL_Data Semantic correctness:

semSL(P,D) = decode(semTL(compile(P), code(D)))

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Language Processing Compiler Architecture

Compiler Architecture

Scanner Source Code

as String

Token Stream

Parser

Name and Type Analysis

Translator

Code Generator Syntax

Tree

Decorated Syntax Tree

(Close to SL)

Intermediate Language

Target Code as String

Attribution &

Optimization

Attribution &

Optimization

Peep Hole Optimization Analysis

Synthesis

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Properties of compiler architectures

• Phases are conceptual units of translation

• Phases can be interleaved

• Design of phases depends on source language, target language and design decisions

• Phase vs.pass(phase can comprise more than one pass)

• Separatecompilation of pogram parts (interface information must be accessible)

• Combination with other architecture decisions:

Common intermediate language

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Common intermediate language

Source Language 1

Source Language 2

Source Language n

Intermediate Language

Target Language 1

Target Language 2

Target Language m ...

...

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Dimensions of compiler construction

• Programming languages

I Sequential procedural, imperative, OO-languages

I Functional, logical languages

I Parallel languages/language constructs

• Target languages/machines

I Code for abstract machines

I Assembler

I Machine languages (CISC, RISC, ...)

I Multi-processor/multi-core architectures

I Memory hierarchy

• Translation tasks: analysis, optimization, synthesis

• Construction techniques and tools: bootstrapping, generators

• Portability, specification, correctness

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Compiler Construction

Compiler construction techniques

1. Stepwise construction

I Construction with compiler for different language

I Construction with compiler for different machine

I Bootstrapping

2. Compiler-compiler: Tools for compiler generation

I Scanner generators (regular expressions)

I Parser generators (context-free grammars)

I Attribute evaluation generators (attribute grammar)

I Code generator generators (machine specification)

I Interpreter generators (semantics of language)

I Other phase-specific tools 3. Special programming techniques

I General technique: syntax-driven

I Special technique: recursive descend

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Stepwise construction

Programming typically depends on an existing compiler for the implementation language. For compiler construction, this does not hold in general.

Source, target, and implementation languages of compilers can be denoted in T-diagrams.

CL SL −→ TL

T-diagram denotes compiler from source languageSLto target languageTL(SL→TLcompiler) written in languageCL.

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Construction with compiler for different language

• Given:C →ML(machine language) compiler inML

• Construct:SL→MLcompiler inML

• Solution: DevelopSL→MLcompiler inC, translate that compiler fromC →MLby using the existingC→MLcompiler

C SL −→ ML

ML

C −→ ML ML SL −→ ML to be developed

existing

by translation

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Construction with compiler for different machine

• Construct:C →ML₁compiler inML₁

• Given

1. C→ML₁compiler inC 2. C→ML₂compiler inML₂

• Method: constructcross compiler First step

C

C −→ ML₁

ML₂

C −→ ML₂ ML₂ C −→ ML₁ cross compiler given

given

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Construction with compiler for different machine (2)

Second step

C

C −→ ML₁

ML₂

C −→ ML₁ ML₁ C −→ ML₁ resulting compiler given

cross compiler

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Bootstrapping

• Construct:SL→MLcompiler inML

• Suppose: yet no compiler exists

• Method:

1. Construct partial languageSL_i ofSLsuch that

SL₀⊂SL₁⊂SL₂⊂. . .⊂SL

2. ImplementSL₀compiler forMLinML 3. ImplementSL_i+1compiler forMLinSL_i 4. CreateSL_i+1compiler forMLinML

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Bootstrapping (2)

SL₀ SL₁ −→ ML

ML

SL₀ −→ ML ML SL₁ −→ ML SL₁

SL₂ −→ ML SL₂ SL −→ ML

ML

SL₂ −→ ML ML SL −→ ML

manually by extension

by translation

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Language processing tools

Compilers and Language Processing Tools

Content of Lecture

Content of Lecture (2)

Outline

Language processing tools

Language processing tools (2)

Language processing tools (3)

Language processing tools (4)

Application domains

Application domains (2)

Related fields

Tasks of Language-Processing Tools

Tasks of Language-Processing Tools (2)

Tasks of Language-Processing Tools (3)

Tasks of Language-Processing Tools (4)

Example: Analysis

Example: Translation

Example: Translation (2)

Example 2: Translation

Example 2: Translation (2)

Example 3: Translation

Example: Interpretation

Example: Combined technique

Language processing: The task of translation

Phases of language processing

Compile time vs. run-time

What is a good compiler?

Requirements for translators

Semantically correct translation

Compiler Architecture

Properties of compiler architectures

Common intermediate language

Dimensions of compiler construction

Compiler construction techniques

Stepwise construction

Construction with compiler for different language

Construction with compiler for different machine

Construction with compiler for different machine (2)

Bootstrapping

Bootstrapping (2)

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