TypeChef is a research project with the goal of type checking ifdef variability in C code with the target of type checking the entire Linux kernel with several thousand features (or configuration options).
Instead of type checking each variant for each feature combination in isolation, TypeChef parses the entire source code containing all variability in a variability-aware fashion without preprocessing. The resulting abstract syntax tree contains the variability in form of choice nodes. Eventually, a variability-aware type system performs type checking on these trees.
TypeChef detects syntax and type errors in all possible feature combinations. TypeChef was originally short for Type Checking Ifdef Variability.
The TypeChef project contains of four main components and several helper libraries.
A variability-aware lexer (also called partial preprocessor; subproject PartialPreprocessor) that reads unpreprocessed code and produces a conditional token stream. The variability-aware lexer is responsible for resolving macros and file inclusions and for normalizing #ifdef conditions
A variability-aware parser framework provides parser combinators to build variability-aware parsers (subproject ParserFramework).
The variability-aware parsers for GNU C and Java (subprojects CParser and JavaParser) use the parser framework to build parsers for the corresponding languages. The parsers read a conditional token stream and produce abstract syntax trees with corresponding choice nodes.
A variability-aware type system (subproject CTypeChecker) eventually checks variability in the abstract syntax tree. This will be supported by variability-aware linker checks.
All tasks are supported by a library for feature expressions and reasoning about feature expressions (subproject FeatureExprLib). Internally the library uses the SAT solver sat4j.
Evaluation specific parts, mostly for Linux are provided in the frontend subproject LinuxAnalysis.
For simple experimentation, try our online version at http://www.mathematik.uni-marburg.de/~kaestner/TypeChef/online/.
Alternatively, you can download a .jar file including all necessary libraries TypeChef.jar. Run as usual
java -jar TypeChef.jar ...TypeChef is also available as a maven repository. With sbt you can include TypeChef with the following line:
scala
libraryDependencies += "de.fosd.typechef" % "frontend_2.9.1" % "0.3.2"
To build TypeChef from source, we use sbt. Install git and download and compile the code as follows
git clone git://github.com/ckaestne/TypeChef.git
cd TypeChef
java -Xmx512M -Xss10m -jar sbt-launch.jar clean update compileDue to library dependencies, setting up the TypeChef classpath can be difficult. There are two convenient mechanisms: Use sbt assembly to build a single jar file. Alternatively, call sbt mkrun to create a script typechef.sh that sets a correct classpath.
Most functionality of TypeChef is accessible through parameters of the main de.fosd.typechef.Frontend class. Call TypeChef with --help to see a list of configuration parameters. See also Parameter.txt. You will need to set up system include paths with -I and a header file with the compiler’s macro definitions with -h (generate, for example, with echo - | gcc -dM - -E -std=gnu99 for gcc). Have a look at existing projects using TypeChef or contact us in case of questions.
IntelliJ Idea users should run sbt gen-idea to create corresponding project and classpath information for the IDE. Similar sbt plugins for Eclipse are available, but we have not tried or integrated them yet. In general avoid to set the classpath in IDEs manually, but let sbt generate corresponding files for you.
Details on our syntax analysis of Linux have been published in an OOPSLA paper (see below). You find additional information on that evaluation at http://www.mathematik.uni-marburg.de/~kaestner/TypeChef/
The project was only possible with fruitful collaboration of many researchers.
The variability-aware lexer is implemented on top of jcpp, an implementation of the C preprocessor in Java.
For reasoning about propositional formulas, we use the SAT solver sat4j.
The GNU C parser is based on an ANTLR grammar for GNU C.
The Java parser is based on a grammar that can be traced back to the Java 1.5 grammar in the JavaCC repository.
For convenience, we include sbt in the repository.
Furthermore, we thank for their contributions and discussions:
This work is supported in part by the European Research Council, grant #203099.
Fork the project, write bug reports, contact us, …. We are open for collaborations and extensions and other scenarios.
An indepth discussion of the parsing approach and our experience with parsing Linux was published at OOPSLA:
Christian Kaestner, Paolo G. Giarrusso, Tillmann Rendel, Sebastian Erdweg, Klaus Ostermann, and Thorsten Berger. Variability-Aware Parsing in the Presence of Lexical Macros and Conditional Compilation. In Proceedings of the 26th Annual ACM SIGPLAN Conference on Object-Oriented Programming, Systems, Languages, and Applications (OOPSLA) (Portland, OR), New York, NY, October 2011. ACM Press.
A discussion of a module system including type checks and linker checks built on top of TypeChef was published as technical report:
Christian Kästner, Klaus Ostermann, and Sebastian Erdweg. A Variability-Aware Module System. Technical Report 01/2012, Department of Mathematics and Computer Science, Philipps University Marburg, April 2012.
An early overview of the project with a very preliminary implementation was published at
Andy Kenner, Christian Kästner, Steffen Haase, and Thomas Leich. TypeChef: Toward Type Checking #ifdef Variability in C. In Proceedings of the Second Workshop on Feature-Oriented Software Development (FOSD) (Eindhoven, The Netherlands), pages 25-32, New York, NY, USA, October 2010. ACM Press.
A more detailed discussion of the variability-aware lexer (or partial preprocessor) was presented at
Christian Kästner, Paolo G. Giarrusso, and Klaus Ostermann. Partial Preprocessing C Code for Variability Analysis. In Proceedings of the Fifth International Workshop on Variability Modelling of Software-intensive Systems (VaMoS) (Namur, Belgium), pages 137-140, New York, NY, USA, January 2011. ACM Press.
TypeChef is published as open source under GPL 3.0. See LICENSE.
You can download this project in either zip or tar formats.
You can also clone the project with Git by running:
$ git clone git://github.com/ckaestne/TypeChef