Page History

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• Thomas Kotzmann, Christian Wimmer, Hanspeter Mössenböck, Thomas Rodriguez, Kenneth Russell, David Cox: Design of the Java HotSpot™ Client Compiler for Java 6. In ACM Transactions on Architecture and Code Optimization, volume 5, issue 1, article 7. ACM Press, 2008. doi:10.1145/1369396.1370017
  Explains the structure of the client compiler, its intermediate representations, and the optimization algorithms. It describes the client compiler of the Java HotSpot™ VM of Java 6. Java 7 and OpenJDK contain no significant changes, so all information up-to-date.

• Christian Wimmer: Linear Scan Register Allocation for the Java HotSpot™ Client Compiler. Master's thesis, Institute for System Software, Johannes Kepler University Linz, 2004.
  Extended description of the client compiler, with a focus on the register allocator. Read Chapter 4 for if you are interested in the details of the compiler and the intermediate representations. The term "research compiler" in this thesis refers to the product version of Java 6 (which was not released at the time of writing).

• Christian Wimmer, Hanspeter Mössenböck: Optimized Interval Splitting in a Linear Scan Register Allocator. In Proceedings of the ACM/USENIX International Conference on Virtual Execution Environments, pages 132-141. ACM Press, 2005. doi:10.1145/1064979.1064998
  Description of the register allocation algorithm of the current client compiler.

• Hanspeter Mössenböck, Michael Pfeiffer: Linear Scan Register Allocation in the Context of SSA Form and Register Constraints. In Proceedings of the International Conference on Compiler Construction, LNCS 2304, pages 229-246. Springer-Verlag, 2002.
  Describes an early version of the work, so it does not reflect the current product version.

• Hanspeter Mössenböck: Adding Static Single Assignment Form and a Graph Coloring Register Allocator to the Java HotSpot™ Client Compiler. Technical Report 15, Institute for Practical Computer Science, Johannes Kepler University Linz, 2000.
  Describes an early version of the work, so it does not reflect the current product version. The graph coloring register allocator was later replaced by the linear scan register allocator.

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• Homepage of the Java HotSpot™ Client Compiler Visualizer: https://c1visualizer.dev.java.net/^{Image Removed}
  The homepage contains the binary download, the source code repository, and the documentation (several bachelor theses and master's theses).

Ideal Graph Visualizer

The Java HotSpot™ server compiler uses a single intermediate representation in all compiler phases, called ideal graph. The tool saves snapshots of the graph during the compilation. It displays the graphs and provides filtering mechanisms based on customizable JavaScript code and regular expressions. High performance and sophisticated navigation possibilities enable the tool to handle large graphs with thousands of nodes. The tool will be part of the OpenJDK soon, but there is no release available yet.

• Thomas Würthinger: Visualization of Program Dependence Graphs. Master's thesis, Institute for System Software, Johannes Kepler University Linz, 2007.
  This thesis describes the architecture and implementation of the tool and also contains a user guide. It does not describe the final version, but is still up-to-date.

• Thomas Würthinger, Christian Wimmer, Hanspeter Mössenböck: Visualization of Program Dependence Graphs. In Proceedings of the International Conference on Compiler Construction, LNCS 4959, pages 193-196. Springer-Verlag, 2008. doi:10.1007/978-3-540-78791-4_13
  A short tool demonstration paper that briefly sketches the purpose and structure of the application.

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• Thomas Würthinger, Christian Wimmer, Hanspeter Mössenböck: Array Bounds Check Elimination for the Java HotSpot™ Client Compiler. In Proceedings of the International Conference on Principles and Practice of Programming in Java, pages 125-133. ACM Press, 2007. doi:10.1145/1294325.1294343
  Conference paper that describes the optimization process, with a focus on the usage of deoptimization to avoid code duplication.

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• Christian Häubl, Christian Wimmer, Hanspeter Mössenböck: Optimized Strings for the Java HotSpot™ Virtual Machine. To be published in Proceedings of the International Conference on Principles and Practice of Programming in Java. ACM Press, 2008.

• Christian Häubl: Optimized Strings for the Java HotSpot™ Virtual Machine. Master's thesis, Institute for System Software, Johannes Kepler University Linz, 2008.
  This thesis describes the complete architecture and implementation of the optimization, together with a comprehensive evaluation.

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In this research project, we implemented a fast algorithm for escape analysis. It detects objects that are accessible only by a single method or thread. Its results are used to replace fields of objects with scalar variables, to allocate objects on the stack instead of the heap, and to remove synchronization. The produced machine code is smaller and executes faster because fewer objects are allocated on the heap and the garbage collector runs less frequently. Deoptimization is used to handle dynamic class loading. There are currently no plans to integrate this work into the product version, however it influenced the implementation of escape analysis for the server compiler.

• Thomas Kotzmann: Escape Analysis in the Context of Dynamic Compilation and Deoptimization. PhD thesis, Institute for System Software, Johannes Kepler University Linz, 2005.
  Describes the details of all algorithms and contains an extensive evaluation as well as a survey of related work.

• Thomas Kotzmann, Hanspeter Mössenböck: Run-Time Support for Optimizations Based on Escape Analysis. In Proceedings of the International Symposium on Code Generation and Optimization, pages 49-60. IEEE Computer Society, 2007. doi:10.1109/CGO.2007.34
  Conference paper that describes the support necessary in the runtime system, the garbage collector, and the deoptimization framework.

• Thomas Kotzmann, Hanspeter Mössenböck: Escape Analysis in the Context of Dynamic Compilation and Deoptimization. In Proceedings of the ACM/USENIX International Conference on Virtual Execution Environments, pages 111-120. ACM Press, 2005. doi:10.1145/1064979.1064996
  Conference paper that describes the core algorithm for escape analysis that is integrated into the client compiler.

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• Christian Wimmer, Hanspeter Mössenböck: Feedback-Directed Object Inlining and Array Inlining. Technical Report, Institute for System Software, Johannes Kepler University Linz, 2008.
  Summary report that covers all parts of the optimization, but does not describe the algorithmic details. Read this if you want to get familiar with the topic.

• Christian Wimmer: Automatic Object Inlining in a Java Virtual Machine. PhD thesis, Institute for System Software, Johannes Kepler University Linz, 2008.
  Describes the details of all algorithms and contains an extensive evaluation as well as a survey of related work. Read this if you are interested in the implementation details.

• Christian Wimmer, Hanspeter Mössenböck: Automatic Array Inlining in Java Virtual Machines. In Proceedings of the International Symposium on Code Generation and Optimization, pages 14-23. ACM Press, 2008. doi:10.1145/1356058.1356061
  Conference paper that covers only the array inlining part of the optimization system.

• Christian Wimmer, Hanspeter Mössenböck: Automatic Feedback-Directed Object Inlining in the Java HotSpot™ Virtual Machine. In Proceedings of the ACM/USENIX International Conference on Virtual Execution Environments, pages 12-21. ACM Press, 2007. doi:10.1145/1254810.1254813
  Conference paper that covers only the object inlining part of the optimization system.

• Christian Wimmer, Hanspeter Mössenböck: Automatic Object Colocation Based on Read Barriers. In Proceedings of the Joint Modular Languages Conference, LNCS 4228, pages 326-345. Springer-Verlag, 2006. doi:10.1007/11860990_20
  Conference paper that covers only the object colocation part. It describes an early version of the work, so it does not fully reflect the final version.