Dipl.-Ing. Dr. Sebastian Kloibhofer, BSc.

Research

Research Interests

• Compilers (AOT, JIT, IRs, Optimizations)
• Performance & Memory Optimization
• Virtual Machines
• Symbolic Execution

Projects

GraalVM

• Symbolic Execution in GraalVM (2019-2020)
  
• Automated Columnar Arrays in GraalVM JavaScript (JavaScript runtime of GraalVM) (2021-2023)
  
• Automated Profile-Guided Replacement of Data Structures in GraalVM Native Image (Ahead-of-Time Compilation of Java Byte Code) (2023-2024)
  
• Automated Profile-Guided Field Externalization in GraalVM Native Image (2024-2025)
  

Presentations

• VMM 2021:
  Program Optimization using Data Analysis
  2021 Virtual Machine Meetup (VMM 2021), September 30, 2021, Virtual
  
  
• SPLASH 2021: [Extended Abstract, Poster]
  Run-Time Data Analysis to Drive Compiler Optimizations
  Student Research Competition, Intl. Conf. on Systems, Programming, Languages, and Applications: Software for Humanity (SPLASH'21), October 17-22, 2021, Virtual
  
  
• SPLASH 2021: [Extended Abstract, Poster]
  Run-time Data Analysis to Drive Compiler Optimizations
  Doctoral Symposium, Intl. Conf. on Systems, Programming, Languages, and Applications: Software for Humanity (SPLASH'21), October 17-22, 2021, Virtual
  
  
• MPLR 2022: [Poster]
  Automatically Transforming Arrays to Columnar Storage at Run Time.
  19th Intl. Conf. on Managed Programming Languages and Runtimes (MPLR'22), September 14-15, 2022, Brussels, Belgium
  
  
• <Programming> 2023:
  Control Flow Duplication for Columnar Arrays in a Dynamic Compiler
  Intl. Conf. on the Art, Science, and Engineering of Programming (<Programming> 2023), March 13-17, 2023, Tokyo, Japan
  
  
• ECOOP 2025:
  Profile-Guided Field Externalization in an Ahead-of-Time Compiler
  European Conference on Object-Oriented Programming (ECOOP'25), 30 June - 4 July, 2025, Bergen, Norway
  
  

Publications

• Sebastian Kloibhofer, Thomas Pointhuber, Maximilian Heisinger, Hanspeter Mössenböck, Lukas Stadler, David Leopoldseder:
  SymJEx: Symbolic Execution on the GraalVM.
  17th International Conference on Managed Programming Languages and Runtimes (MPLR'20), November 4, 2020, Virtual UK, pp.63-72
  
  
• Sebastian Kloibhofer:
  Run-time Data Analysis to Drive Compiler Optimizations.
  ACM Student Research Competition at SPLASH'21, Oct. 17-22, 2021, Chicago, IL, USA, pp.9-12
  Won 2nd place in the graduate category
  
  
• Sebastian Kloibhofer:
  Run-time Data Analysis to Drive Compiler Optimizations.
  SPLASH Doctoral Symposium at SPLASH'21, Oct. 17-22, 2021, Chicago, IL, USA
  
  
• Sebastian Kloibhofer, Lukas Makor, David Leopoldseder, Daniele Bonetta, Lukas Stadler, Hanspeter Mössenböck:
  Automatically Transforming Arrays to Columnar Storage at Run Time.
  Poster, 19th Intl. Conf. on Managed Programming Languages and Runtimes (MPLR'22), Brussels, Sept. 14-15, 2022, pp.16-28
  
  
• Lukas Makor, Sebastian Kloibhofer, David Leopoldseder, Daniele Bonetta, Lukas Stadler, Hanspeter Mössenböck:
  Automatic Array Transformation to Columnar Storage at Run Time.
  19th Intl. Conf. on Managed Programming Languages and Runtimes (MPLR'22), Brussels, Sept. 14-15, 2022, pp.16-28
  
  
• Sebastian Kloibhofer, Lukas Makor, David Leopoldseder, Daniele Bonetta, Lukas Stadler, Hanspeter Mössenböck:
  Control Flow Duplication for Columnar Arrays in a Dynamic Compiler.
  The Programming Journal, vol. 7, issue 3, article 9, February 2023, pp.1-38
  Presentation at the <Programming> Conference 2023, March 13-17, 2023, Tokyo, Japan
  
  
• Lukas Makor, Sebastian Kloibhofer, Peter Hofer, David Leopoldseder, Hanspeter Mössenböck:
  Automated Profile-Guided Replacement of Data Structures to Reduce Memory Allocation.
  The Art, Science, and Engineering of Programming, 2025, Vol. 10, Issue 1, Article 3
  
  
• Sebastian Kloibhofer, Lukas Makor, Peter Hofer, David Leopoldseder, Hanspeter Mössenböck:
  Profile-Guided Field Externalization in an Ahead-of-Time Compiler.
  European Conference on Object-Oriented Programming (ECOOP'25), 30 June - 4 July, 2025, Bergen, Norway, Leibniz International Proceedings in Informatics (LIPIcs), Vol. 333, pp. 19:1-19:32
  
  

Teaching

Courses

• Übung zu Softwareentwicklung 1: 2020W, 2021S, 2021W, 2022W, 2023W, 2024W
• Übung zu Softwareentwicklung 2: 2022S, 2023S, 2024S, 2025S

Supervised Theses