Unboxing Virgil ADTs for Fun and Profit
Pages 43 - 52
Abstract
Algebraic Data Types (ADTs) are an increasingly common feature in modern programming languages. In many implementations, values of non-nullary, multi-case ADTs are allocated on the heap, which may reduce performance and increase memory usage. This work explores annotation-guided optimizations to ADT representation in Virgil, a systems-level programming language that compiles to x86, x86-64, WebAssembly and the Java Virtual Machine. We extend Virgil with annotations: #unboxed to eliminate the overhead of heap allocation via automatic compiler transformation to a scalar representation, and #packed, to enable programmer-expressed bit-layouts. These annotations allow programmers to both save memory and manipulate data in formats dictated by hardware. We dedicate this work as an homage and echo of work done in collaboration with Jens in the work entitled "A Declarative Approach to Generating Machine Code Tools", an unpublished manuscript from 2005. In fact, this work inherits some syntactic conventions from that prior work. The performance impact of these representation changes was evaluated on a variety of workloads in terms of execution time and memory usage, but we don't include all of that because Jens like semantics and type systems better!
References
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Noah Lev Bartell-Mangel. 2022. Filling a Niche: Using Spare Bits to Optimize Data Representations.
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Thaïs Baudon, Gabriel Radanne, and Laure Gonnord. 2023. Bit-Stealing Made Legal: Compilation for Custom Memory Representations of Algebraic Data Types. Proc. ACM Program. Lang., 7, ICFP (2023), Article 216, aug, 34 pages. https://doi.org/10.1145/3607858
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Nicolas Chataing, Stephen Dolan, Gabriel Scherer, and Jeremy Yallop. 2023. Unboxed data constructors – or, how cpp decides a halting problem. arxiv:2311.07369.
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Nicolas Chataing, Stephen Dolan, Gabriel Scherer, and Jeremy Yallop. 2024. Unboxed Data Constructors: Or, How cpp Decides a Halting Problem. Proc. ACM Program. Lang., 8, POPL (2024), Article 51, jan, 31 pages. https://doi.org/10.1145/3632893
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Richard Eisenberg. 2022. Unboxed Types. https://github.com/goldfirere/ocaml-rfcs/blob/unboxed-types/rfcs/unboxed-types.md
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Ben L. Titzer. 2006. Virgil: objects on the head of a pin. In Proceedings of the 21st Annual ACM SIGPLAN Conference on Object-Oriented Programming Systems, Languages, and Applications (OOPSLA ’06). Association for Computing Machinery, New York, NY, USA. 191–208. isbn:1595933484 https://doi.org/10.1145/1167473.1167489
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Ben L. Titzer. 2013. Harmonizing classes, functions, tuples, and type parameters in Virgil III. SIGPLAN Not., 48, 6 (2013), Jun, 85–94. issn:0362-1340 https://doi.org/10.1145/2499370.2491962
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Mingzhe Wang, Jie Liang, Chijin Zhou, Zhiyong Wu, Xinyi Xu, and Yu Jiang. 2022. Odin: On-Demand Instrumentation with on-the-Fly Recompilation. In Proceedings of the 43rd ACM SIGPLAN International Conference on Programming Language Design and Implementation (PLDI 2022). Association for Computing Machinery, New York, NY, USA. 1010–1024. isbn:9781450392655 https://doi.org/10.1145/3519939.3523428
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Index Terms
- Unboxing Virgil ADTs for Fun and Profit
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Published In
October 2024
58 pages
ISBN:9798400712579
DOI:10.1145/3694848
- General Chairs:
- Mayur Naik,
- Fernando Magno Quintão Pereira,
- Ben L. Titzer
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Published: 22 October 2024
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JENSFEST '24: Workshop Dedicated to Jens Palsberg on the Occasion of His 60th Birthday
October 22, 2024
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