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Ownership, Uniqueness, and Immutability
Purdue University.
Purdue University.
Stockholms Universitet.
2008 (English)In: Lecture Notes in Business Information Processing, ISSN 1865-1348Article in journal (Refereed) Published
Abstract [en]

Programming in an object-oriented language demands a fine balance between flexibility and control. At one level, objects need to interact freely to achieve our implementation goals. At a higher level, architectural constraints that ensure the system can be understood by new developers and can evolve as requirements change must be met. To resolve this tension, researchers have developed type systems expressing ownership and behavioural restrictions such as immutability. This work reports on our consolidation of the resulting discoveries into a single programming language. Our language, Joe 3 , imposes little additional syntactic overhead, yet can encode powerful patterns such as fractional permissions and the reference modes of Flexible Alias Protection.

Place, publisher, year, edition, pages
National Category
Computer Science
URN: urn:nbn:se:uu:diva-266671DOI: 10.1007/978-3-540-69824-1_11OAI: oai:DiVA.org:uu-266671DiVA: diva2:868451
46th International Conference, TOOLS EUROPE 2008, Zurich, Switzerland, June 30 - July 4, 2008.
Available from: 2015-11-10 Created: 2015-11-10 Last updated: 2016-01-13
In thesis
1. Language Constructs for Safe Parallel Programming on Multi-Cores
Open this publication in new window or tab >>Language Constructs for Safe Parallel Programming on Multi-Cores
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The last decade has seen the transition from single-core processors to multi-cores and many-cores. This move has by and large shifted the responsibility from chip manufacturers to programmers to keep up with ever-increasing expectations on performance. In the single-core era, improvements in hardware capacity could immediately be leveraged by an application: faster machine - faster program. In the age of the multi-cores, this is no longer the case. Programs must be written in specific ways to utilize available parallel hardware resources.

Programming language support for concurrent and parallel programming is poor in most popular object-oriented programming languages. Shared memory, threads and locks is the most common concurrency model provided. Threads and locks are hard to understand, error-prone and inflexible; they break encapsulation - the very foundation of the object-oriented approach. This makes it hard to break large complex problems into smaller pieces which can be solved independently and composed to make a whole. Ubiquitous parallelism and object-orientation, seemingly, do not match.

Actors, or active objects, have been proposed as a concurrency model better fit for object-oriented programming than threads and locks. Asynchronous message passing between actors each with a logical thread of control preserves encapsulation as objects themselves decide when messages are executed. Unfortunately most implementations of active objects do not prevent sharing of mutable objects across actors. Sharing, whether on purpose or by accident, exposes objects to multiple threads of control, destroying object encapsulation.

In this thesis we show techniques for compiler-enforced isolation of active objects, while allowing sharing and zero-copy communication of mutable data in the cases where it is safe to do so. We also show how the same techniques that enforce isolation can be utilized internal to an active object to allow data race-free parallel message processing and data race-free structured parallel computations. This overcomes the coarse-grained nature of active object parallelism without compromising safety.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2016. 105 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1319
Programming Languages, Type Systems, Ownership Types, Concurrency, Parallelism, Actors, Active Objects, Structured Parallelism, Data Race-Freedom, Immutability, Uniqueness
National Category
Computer Science
Research subject
Computer Science
urn:nbn:se:uu:diva-266795 (URN)978-91-554-9413-1 (ISBN)
Public defence
2016-01-18, 2446, ITC, Lägerhyddsvägen 2, hus 2, Uppsala, 13:00 (English)
Available from: 2015-12-17 Created: 2015-11-10 Last updated: 2016-04-18Bibliographically approved

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Östlund, Johan
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