Reenix: Implementing a Unix-Like Operating System in Rust
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Project1: Build a Small Scanner/Parser
Project1: Build A Small Scanner/Parser Introducing Lex, Yacc, and POET cs5363 1 Project1: Building A Scanner/Parser Parse a subset of the C language Support two types of atomic values: int float Support one type of compound values: arrays Support a basic set of language concepts Variable declarations (int, float, and array variables) Expressions (arithmetic and boolean operations) Statements (assignments, conditionals, and loops) You can choose a different but equivalent language Need to make your own test cases Options of implementation (links available at class web site) Manual in C/C++/Java (or whatever other lang.) Lex and Yacc (together with C/C++) POET: a scripting compiler writing language Or any other approach you choose --- must document how to download/use any tools involved cs5363 2 This is just starting… There will be two other sub-projects Type checking Check the types of expressions in the input program Optimization/analysis/translation Do something with the input code, output the result The starting project is important because it determines which language you can use for the other projects Lex+Yacc ===> can work only with C/C++ POET ==> work with POET Manual ==> stick to whatever language you pick This class: introduce Lex/Yacc/POET to you cs5363 3 Using Lex to build scanners lex.yy.c MyLex.l lex/flex lex.yy.c a.out gcc/cc Input stream a.out tokens Write a lex specification Save it in a file (MyLex.l) Compile the lex specification file by invoking lex/flex lex MyLex.l A lex.yy.c file is generated -
GNU M4, Version 1.4.7 a Powerful Macro Processor Edition 1.4.7, 23 September 2006
GNU M4, version 1.4.7 A powerful macro processor Edition 1.4.7, 23 September 2006 by Ren´eSeindal This manual is for GNU M4 (version 1.4.7, 23 September 2006), a package containing an implementation of the m4 macro language. Copyright c 1989, 1990, 1991, 1992, 1993, 1994, 2004, 2005, 2006 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled “GNU Free Documentation License.” i Table of Contents 1 Introduction and preliminaries ................ 3 1.1 Introduction to m4 ............................................. 3 1.2 Historical references ............................................ 3 1.3 Invoking m4 .................................................... 4 1.4 Problems and bugs ............................................. 8 1.5 Using this manual .............................................. 8 2 Lexical and syntactic conventions ............ 11 2.1 Macro names ................................................. 11 2.2 Quoting input to m4........................................... 11 2.3 Comments in m4 input ........................................ 11 2.4 Other kinds of input tokens ................................... 12 2.5 How m4 copies input to output ................................ 12 3 How to invoke macros........................ -
GNU M4, Version 1.4.19 a Powerful Macro Processor Edition 1.4.19, 28 May 2021
GNU M4, version 1.4.19 A powerful macro processor Edition 1.4.19, 28 May 2021 by Ren´eSeindal, Fran¸coisPinard, Gary V. Vaughan, and Eric Blake ([email protected]) This manual (28 May 2021) is for GNU M4 (version 1.4.19), a package containing an implementation of the m4 macro language. Copyright c 1989{1994, 2004{2014, 2016{2017, 2020{2021 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled \GNU Free Documentation License." i Table of Contents 1 Introduction and preliminaries ::::::::::::::::: 3 1.1 Introduction to m4 :::::::::::::::::::::::::::::::::::::::::::::: 3 1.2 Historical references :::::::::::::::::::::::::::::::::::::::::::: 3 1.3 Problems and bugs ::::::::::::::::::::::::::::::::::::::::::::: 4 1.4 Using this manual :::::::::::::::::::::::::::::::::::::::::::::: 5 2 Invoking m4::::::::::::::::::::::::::::::::::::::: 7 2.1 Command line options for operation modes ::::::::::::::::::::: 7 2.2 Command line options for preprocessor features ::::::::::::::::: 8 2.3 Command line options for limits control ::::::::::::::::::::::: 10 2.4 Command line options for frozen state ::::::::::::::::::::::::: 11 2.5 Command line options for debugging :::::::::::::::::::::::::: 11 2.6 Specifying input files on the command line ::::::::::::::::::::: -
An AWK to C++ Translator
An AWK to C++ Translator Brian W. Kernighan Bell Laboratories Murray Hill, NJ 07974 [email protected] ABSTRACT This paper describes an experiment to produce an AWK to C++ translator and an AWK class definition and supporting library. The intent is to generate efficient and read- able C++, so that the generated code will run faster than interpreted AWK and can also be modified and extended where an AWK program could not be. The AWK class and library can also be used independently of the translator to access AWK facilities from C++ pro- grams. 1. Introduction An AWK program [1] is a sequence of pattern-action statements: pattern { action } pattern { action } ... A pattern is a regular expression, numeric expression, string expression, or combination of these; an action is executable code similar to C. The operation of an AWK program is for each input line for each pattern if the pattern matches the input line do the action Variables in an AWK program contain string or numeric values or both according to context; there are built- in variables for useful values such as the input filename and record number. Operators work on strings or numbers, coercing the types of their operands as necessary. Arrays have arbitrary subscripts (‘‘associative arrays’’). Input is read and input lines are split into fields, called $1, $2, etc. Control flow statements are like those of C: if-else, while, for, do. There are user-defined and built-in functions for arithmetic, string, regular expression pattern-matching, and input and output to/from arbitrary files and processes. -
Make a Jump Start Together with Software Ag
Software AG Fast Startup FAST STARTUP PROGRAM MAKE A JUMP START TOGETHER WITH SOFTWARE AG You have great ideas, a clear vision and the drive to build something really cool. You are smart, you are fast, you are innovative and you are determined to become a rock star of the startup community. Need some free software to build your solution on? Here’s the secret. When it comes to software partnership, the key differentiators are: technology leadership, ease of use, total cost of ownership and—most importantly—reliability. Why Software AG? Why not just freeware? The key to your success is a brilliant business idea, a sustainable For a homegrown, non-mission-critical application, there is business model, openhanded investors and finally paying nothing wrong with choosing freeware. But if you need best-in- customers. class functionality and reliability to build your business on, you It’s a strong partnership that can be the differentiator in the should think twice about the software you use. success of your business. What is your innovation? What do you require as the foundation That’s why you should partner with Software AG. for your intellectual property? Why should you spend time re- Building on 45 years of customer-centric innovation, we are inventing what professional developers invented and optimized ranked as a leader in key market categories, year after year. Our over many years for their paying customers? Do you want to grow solutions are faster to implement and easier to use than anything your business or just your development team? How reliable are else on the market. -
Intermediate Representation and LLVM
CS153: Compilers Lecture 6: Intermediate Representation and LLVM Stephen Chong https://www.seas.harvard.edu/courses/cs153 Contains content from lecture notes by Steve Zdancewic and Greg Morrisett Announcements •Homework 1 grades returned •Style •Testing •Homework 2: X86lite •Due Tuesday Sept 24 •Homework 3: LLVMlite •Will be released Tuesday Sept 24 Stephen Chong, Harvard University 2 Today •Continue Intermediate Representation •Intro to LLVM Stephen Chong, Harvard University 3 Low-Level Virtual Machine (LLVM) •Open-Source Compiler Infrastructure •see llvm.org for full documentation •Created by Chris Lattner (advised by Vikram Adve) at UIUC •LLVM: An infrastructure for Multi-stage Optimization, 2002 •LLVM: A Compilation Framework for Lifelong Program Analysis and Transformation, 2004 •2005: Adopted by Apple for XCode 3.1 •Front ends: •llvm-gcc (drop-in replacement for gcc) •Clang: C, objective C, C++ compiler supported by Apple •various languages: Swift, ADA, Scala, Haskell, … •Back ends: •x86 / Arm / PowerPC / etc. •Used in many academic/research projects Stephen Chong, Harvard University 4 LLVM Compiler Infrastructure [Lattner et al.] LLVM llc frontends Typed SSA backend like IR code gen 'clang' jit Optimizations/ Transformations Analysis Stephen Chong, Harvard University 5 Example LLVM Code factorial-pretty.ll define @factorial(%n) { •LLVM offers a textual %1 = alloca %acc = alloca store %n, %1 representation of its IR store 1, %acc •files ending in .ll br label %start start: %3 = load %1 factorial64.c %4 = icmp sgt %3, 0 br %4, label -
The Cool Reference Manual∗
The Cool Reference Manual∗ Contents 1 Introduction 3 2 Getting Started 3 3 Classes 4 3.1 Features . 4 3.2 Inheritance . 5 4 Types 6 4.1 SELF TYPE ........................................... 6 4.2 Type Checking . 7 5 Attributes 8 5.1 Void................................................ 8 6 Methods 8 7 Expressions 9 7.1 Constants . 9 7.2 Identifiers . 9 7.3 Assignment . 9 7.4 Dispatch . 10 7.5 Conditionals . 10 7.6 Loops . 11 7.7 Blocks . 11 7.8 Let . 11 7.9 Case . 12 7.10 New . 12 7.11 Isvoid . 12 7.12 Arithmetic and Comparison Operations . 13 ∗Copyright c 1995-2000 by Alex Aiken. All rights reserved. 1 8 Basic Classes 13 8.1 Object . 13 8.2 IO ................................................. 13 8.3 Int................................................. 14 8.4 String . 14 8.5 Bool . 14 9 Main Class 14 10 Lexical Structure 14 10.1 Integers, Identifiers, and Special Notation . 15 10.2 Strings . 15 10.3 Comments . 15 10.4 Keywords . 15 10.5 White Space . 15 11 Cool Syntax 17 11.1 Precedence . 17 12 Type Rules 17 12.1 Type Environments . 17 12.2 Type Checking Rules . 18 13 Operational Semantics 22 13.1 Environment and the Store . 22 13.2 Syntax for Cool Objects . 24 13.3 Class definitions . 24 13.4 Operational Rules . 25 14 Acknowledgements 30 2 1 Introduction This manual describes the programming language Cool: the Classroom Object-Oriented Language. Cool is a small language that can be implemented with reasonable effort in a one semester course. Still, Cool retains many of the features of modern programming languages including objects, static typing, and automatic memory management. -
Ryan Holland CSC415 Term Paper Final Draft Language: Swift (OSX)
Ryan Holland CSC415 Term Paper Final Draft Language: Swift (OSX) Apple released their new programming language "Swift" on June 2nd of this year. Swift replaces current versions of objective-C used to program in the OSX and iOS environments. According to Apple, swift will make programming apps for these environments "more fun". Swift is also said to bring a significant boost in performance compared to the equivalent objective-C. Apple has not released an official document stating the reasoning behind the launch of Swift, but speculation is that it was a move to attract more developers to the iOS platform. Swift development began in 2010 by Chris Lattner, but would later be aided by many other programmers. Swift employs ideas from many languages into one, not only from objective-C. These languages include Rust, Haskell, Ruby, Python, C#, CLU mainly but many others are also included. Apple says that most of the language is built for Cocoa and Cocoa Touch. Apple claims that Swift is more friendly to new programmers, also claiming that the language is just as enjoyable to learn as scripting languages. It supports a feature known as playgrounds, that allow programmers to make modifications on the fly, and see results immediately without the need to build the entire application first. Apple controls most aspects of this language, and since they control so much of it, they keep a detailed records of information about the language on their developer site. Most information within this paper will be based upon those records. Unlike most languages, Swift has a very small set of syntax that needs to be shown compared to other languages. -
Usability Improvements for Products That Mandate Use of Command-Line Interface: Best Practices
Usability improvements for products that mandate use of command-line interface: Best Practices Samrat Dutta M.Tech, International Institute of Information Technology, Electronics City, Bangalore Software Engineer, IBM Storage Labs, Pune [email protected] ABSTRACT This paper provides few methods to improve the usability of products which mandate the use of command-line interface. At present many products make command-line interfaces compulsory for performing some operations. In such environments, usability of the product becomes the link that binds the users with the product. This paper provides few mechanisms like consolidated hierarchical help structure for the complete product, auto-complete command-line features, intelligent command suggestions. These can be formalized as a pattern and can be used by software companies to embed into their product's command-line interfaces, to simplify its usability and provide a better experience for users so that they can adapt with the product much faster. INTRODUCTION Products that are designed around a command-line interface (CLI), often strive for usability issues. A blank prompt with a cursor blinking, waiting for input, does not provide much information about the functions and possibilities available. With no click-able option and hover over facility to view snippets, some users feel lost. All inputs being commands, to learn and gain expertise of all of them takes time. Considering that learning a single letter for each command (often the first letter of the command is used instead of the complete command to reduce stress) is not that difficult, but all this seems useless when the command itself is not known. -
LLVM Overview
Overview Brandon Starcheus & Daniel Hackney Outline ● What is LLVM? ● History ● Language Capabilities ● Where is it Used? What is LLVM? What is LLVM? ● Compiler infrastructure used to develop a front end for any programming language and a back end for any instruction set architecture. ● Framework to generate object code from any kind of source code. ● Originally an acronym for “Low Level Virtual Machine”, now an umbrella project ● Intended to replace the GCC Compiler What is LLVM? ● Designed to be compatible with a broad spectrum of front ends and computer architectures. What is LLVM? LLVM Project ● LLVM (Compiler Infrastructure, our focus) ● Clang (C, C++ frontend) ● LLDB (Debugger) ● Other libraries (Parallelization, Multi-level IR, C, C++) What is LLVM? LLVM Project ● LLVM (Compiler Infrastructure, our focus) ○ API ○ llc Compiler: IR (.ll) or Bitcode (.bc) -> Assembly (.s) ○ lli Interpreter: Executes Bitcode ○ llvm-link Linker: Bitcode (.bc) -> Bitcode (.bc) ○ llvm-as Assembler: IR (.ll) -> Bitcode (.bc) ○ llvm-dis Disassembler: Bitcode (.bc) -> IR (.ll) What is LLVM? What is LLVM? Optimizations History History ● Developed by Chris Lattner in 2000 for his grad school thesis ○ Initial release in 2003 ● Lattner also created: ○ Clang ○ Swift ● Other work: ○ Apple - Developer Tools, Compiler Teams ○ Tesla - VP of Autopilot Software ○ Google - Tensorflow Infrastructure ○ SiFive - Risc-V SoC’s History Language Capabilities Language Capabilities ● Infinite virtual registers ● Strongly typed ● Multiple Optimization Passes ● Link-time and Install-time -
Improving Program Reconstruction in LLDB Using C++ Modules
Beyond Debug Information: Improving Program Reconstruction in LLDB using C++ Modules Master’s Thesis in Computer Science and Engineering RAPHAEL ISEMANN Department of Computer Science and Engineering CHALMERS UNIVERSITY OF TECHNOLOGY UNIVERSITY OF GOTHENBURG Gothenburg, Sweden 2019 Master’s thesis 2019 Beyond Debug Information: Improving Program Reconstruction in LLDB using C++ Modules Raphael Isemann Department of Computer Science and Engineering Chalmers University of Technology University of Gothenburg Gothenburg, Sweden 2019 Beyond Debug Information: Improving Program Reconstruction in LLDB using C++ Modules Raphael Isemann © Raphael Isemann, 2019. Supervisor: Thomas Sewell, Department of Computer Science and Engineering Examiner: Magnus Myreen, Department of Computer Science and Engineering Master’s Thesis 2019 Department of Computer Science and Engineering Chalmers University of Technology and University of Gothenburg SE-412 96 Gothenburg Telephone +46 31 772 1000 Cover: The LLVM logo, owned by and royality-free licensed from Apple Inc. Typeset in LATEX Gothenburg, Sweden 2019 iv Beyond Debug Information: Improving Program Reconstruction in LLDB using C++ Modules Raphael Isemann Department of Computer Science and Engineering Chalmers University of Technology and University of Gothenburg Abstract Expression evaluation is a core feature of every modern C++ debugger. Still, no C++ debugger currently features an expression evaluator that consistently supports advanced language features such as meta-programming with templates. The under- lying problem is that the debugger can often only partially reconstruct the debugged program from the debug information. This thesis presents a solution to this problem by using C++ modules as an additional source of program information. We devel- oped a prototype based on the LLDB debugger that is loading missing program components from the C++ modules used by the program. -
The AWK Pattern Processing Language
000.book.fm Page 531 Wednesday, September 30, 2009 10:13 AM 12 The AWK Pattern Processing Language In This Chapter AWK12Chapter12 is a pattern-scanning and processing language that searches one or more files for records (usually lines) that Syntax . 532 match specified patterns. It processes lines by performing Arguments . 532 actions, such as writing the record to standard output or Options . 533 incrementing a counter, each time it finds a match. Unlike procedural languages, AWK is data driven: You describe the Patterns . 534 data you want to work with and tell AWK what to do with Actions. 535 the data once it finds it. Variables . 535 You can use AWK to generate reports or filter text. It works Functions. 536 equally well with numbers and text; when you mix the two, Associative Arrays. 538 AWK usually comes up with the right answer. The authors of AWK (Alfred V. Aho, Peter J. Weinberger, and Brian W. Control Structures . 539 Kernighan) designed the language to be easy to use. To Examples . 541 achieve this end they sacrificed execution speed in the origi- getline: Controlling Input . 558 nal implementation. Coprocess: Two-Way I/O. 560 Getting Input from a Network. 562 Copyright © 2010 Mark G. Sobell 531531 000.book.fm Page 532 Wednesday, September 30, 2009 10:13 AM 532 Chapter 12 The AWK Pattern Processing Language AWK takes many of its constructs from the C programming language. It includes the following features: • A flexible format • Conditional execution • Looping statements • Numeric variables • String variables • Regular expressions • Relational expressions •C’s printf • Coprocess execution (gawk only) • Network data exchange (gawk only) Syntax A gawk command line has the following syntax: gawk [options] [program] [file-list] gawk [options] –f program-file [file-list] The gawk utility takes its input from files you specify on the command line or from standard input.