Stable object identity and shared mutable state are two powerful principles in programming. The ability to create multiple aliases to mutable data allows a direct modelling of sharing that occurs naturally in a domain, and lies at the heart of efficient programming patterns where aliases provide shortcuts to key places in a data structure. However, aliasing is also the cause of low-level bugs which are notoriously hard to debug, where a change through one alias may cause unforeseen changes visible through another alias. These problems are particularly important in a concurrent setting, where data races are caused by multiple threads sharing aliased references to mutable state.
Coping with pointers, aliasing and the proliferation of shared mutable state is a problem that crosscuts the software development stack, from compilers and runtimes to bug-finding tools and end-user software. They complicate modular reasoning and program analysis, efficient code generation, efficient use of memory, and obfuscate program logic. Furthermore, in a setting where access to effects and resources is mediated with capabilities, reasoning about capability aliasing is also reasoning about side effects and resource lifetimes, providing a link to two other fundamental problems.
Many techniques have been introduced to describe and reason about stateful programs, and to restrict, analyze, and prevent aliases. These include various forms of ownership types, capabilities, separation logic, linear logic, uniqueness, sharing control, escape analysis, argument independence, read-only references, linear references, effect systems, and access control mechanisms. These tools have found their way into type systems, compilers and interpreters, runtime systems and bug-finding tools. Their immediate practical relevance is self-evident from the popularity of Rust, a programming language built around reasoning about aliasing and ownership to enable static memory management and data race freedom, voted the “most beloved” in the annual Stack Overflow Developer Survey seven times in a row.
IWACO’23 will focus on these techniques, on how they can be used to reason about stateful (sequential or concurrent) programs, and how they have been applied to programming languages. In particular, we will consider papers on:
- models, type systems and other formal systems, programming language mechanisms, analysis and design techniques, patterns and notations for expressing ownership, aliasing, capabilities, uniqueness, and related topics;
- empirical studies of programs or experience reports from programming systems designed with these techniques in mind;
- programming logics that deal with aliasing and/or shared state, or use ownership, capabilities or resourcing;
- applications of capabilities, ownership and other similar type systems in low-level systems such as programming languages runtimes, virtual machines, or compilers; and
- optimization techniques, analysis algorithms, libraries, applications, and novel approaches exploiting ownership, aliasing, capabilities, uniqueness, and related topics.
Tue 24 OctDisplayed time zone: Lisbon change
09:00 - 10:30
|Welcome to IWACO!
|Capture Tracking in Scala
Martin Odersky EPFL
11:00 - 12:30
|Borrow checking Hylo
|Degrees of Separation: A Flexible Type System for Data Race Prevention
|Latte: Lightweight Aliasing Tracking for Java
Conrad Zimmerman Brown University, Catarina Gamboa Carnegie Mellon University and LASIGE, University of Lisbon, Alcides Fonseca LASIGE, University of Lisbon, Jonathan Aldrich Carnegie Mellon UniversityPre-print
14:00 - 15:30
|A Mechanized Theory of the Box Calculus
|Compositional Reasoning about Advanced Iterator Patterns in Rust
Aurel Bílý ETH Zurich, Jonas Hansen ETH Zurich, Alexander J. Summers University of British Columbia, Peter Müller ETH ZurichFile Attached
|Oxidize: A Step-Debugger for Static Semantics
Peter Chon Harvard University, Dimi Racordon Northeastern University, USA, Nada Amin Harvard UniversityFile Attached
Call for Papers
We welcome submissions describing novel ideas, open questions, (preliminary) research results, or projects related to the workshop’s topics. Submitted papers can describe work-in-progress, to help foster a healthy discussion. Submissions should be up to 6 pages long, excluding references and clearly marked appendices. Submissions above the page limit will not be rejected, but the reviewers are free to ignore all content above the page limit they do not find engaging. We also encourage submissions below the page limit, for instance well-written 1- or 2-page abstracts describing an interesting idea.
Papers must be prepared in LaTeX, adhering to the ACM format available at http://sigplan.org/Resources/Author/#acmart-format using the
sigplan option. The review process is single-blind: reviewers can see the submission’s authors.
Papers must be submitted via HotCRP: https://iwaco23.hotcrp.com.
Accepted submissions can be presented both in-person and remotely.