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Region-based memory management offers several important potential advantages over garbage collection, including real-time performance, better data locality, and more efficient use of limited memory. Researchers have advocated the use of... more
Region-based memory management offers several important potential advantages over garbage collection, including real-time performance, better data locality, and more efficient use of limited memory. Researchers have advocated the use of regions for functional, imperative, and object-oriented languages. Lexically scoped regions are now a core feature of the Real-Time Specification for Java (RTSJ)[5].Recent research in region-based programming for Java has focused on region checking, which requires manual effort to augment the program with region annotations. In this paper, we propose an automatic region inference system for a core subset of Java. To provide an inference method that is both precise and practical, we support classes and methods that are region-polymorphic, with region-polymorphic recursion for methods. One challenging aspect is to ensure region safety in the presence of features such as class subtyping, method overriding, and downcast operations. Our region inference r...
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Many program optimisations and analyses, such as array-bound checking, termination analysis, etc, depend on knowing the size of a function's input and output. However, size information can be difficult to compute. Firstly, accurate... more
Many program optimisations and analyses, such as array-bound checking, termination analysis, etc, depend on knowing the size of a function's input and output. However, size information can be difficult to compute. Firstly, accurate size computation requires detecting size relation between different inputs of a function. Secondly, different optimisations and analyses may require slightly different size information, and thus slightly different computation. Literature in size computation has mainly concentrated on size checking, instead of inferencing. In this paper, we provide a generic framework on which different size variants can be expressed and computed. We also describe an effective algorithm for inferring , instead of checking, size information. Size information are expressed in terms of Presburger formulae, and our algorithm utilises the Omega Calculator to compute as exact a size information as possible, within the linear arithmetic capability.
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In the current work, we investigate the benefits of immutability guarantees for allowing more flexible handling of aliasing, as well as more precise and concise specifications. Our approach supports finer levels of control that can mark... more
In the current work, we investigate the benefits of immutability guarantees for allowing more flexible handling of aliasing, as well as more precise and concise specifications. Our approach supports finer levels of control that can mark data structures as being immutable through the use of immutability annotations. By using such annotations to encode immutability guarantees, we expect to obtain better specifications that can more accurately describe the intentions, as well as prohibitions, of the method. Ultimately, our goal is improving the precision of the verification process, as well as making the specifications more readable, more precise and as an enforceable program documentation. We have designed and implemented a new entailment procedure to formally and automatically reason about immutability enhanced specifications. We have also formalised the soundness for our new procedure through an operational semantics with mutability assertions on the heap. Lastly, we have carried ou...
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Region-based memory management offers several important advantages over garbage-collected heap, including real-time performance, better data locality and efficient use of limited memory. The concept of regions was first introduced for a... more
Region-based memory management offers several important advantages over garbage-collected heap, including real-time performance, better data locality and efficient use of limited memory. The concept of regions was first introduced for a call-by-value functional language by Tofte and Talpin, and has since been advocated for imperative and object-oriented languages. Scope memory, a lexical variant of regions, is now a core feature in a recent proposal on Real-Time Specification for Java (RTSJ). In this paper, we propose a ...
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We propose in this paper an algebraic approach to hard-ware/software partitioning in Verilog Hardware Description Language (HDL). We explore a collection of algebraic laws for Verilog programs, from which we design a set of syntax-based... more
We propose in this paper an algebraic approach to hard-ware/software partitioning in Verilog Hardware Description Language (HDL). We explore a collection of algebraic laws for Verilog programs, from which we design a set of syntax-based algebraic rules to conduct hardware/software partitioning. The co-specification language and the target hardware and software description languages are specific subsets of Verilog. Through this, we confirm successful verification for the correctness of the partitioning process by an algebra of ...
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We present a new (size-) polymorphic type system (for an objectoriented language) that characterizes the sizes of data structures and the amount of heap and stack memory required to successfully execute methods that operate on these data... more
We present a new (size-) polymorphic type system (for an objectoriented language) that characterizes the sizes of data structures and the amount of heap and stack memory required to successfully execute methods that operate on these data structures. Key components of this type system include type assertions that use symbolic Presburger arithmetic expressions to capture data structure sizes, the effect of methods on the sizes of the data structures that they manipulate, and the amount of memory that methods allocate ...
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Conventional specifications for object-oriented (OO) programs must adhere to behavioral subtyping in support of class inheritance and method overriding. However, this requirement inherently weakens the specifications of overridden methods... more
Conventional specifications for object-oriented (OO) programs must adhere to behavioral subtyping in support of class inheritance and method overriding. However, this requirement inherently weakens the specifications of overridden methods in superclasses, leading to imprecision during program reasoning. To address this, we advocate a fresh approach to OO verification that focuses on the distinction and relation between specifications that cater to calls with static dispatching from those for calls with dynamic dispatching. We formulate a novel specification subsumption that can avoid code re-verification, where possible. Using a predicate mechanism, we propose a flexible scheme for supporting class invariant and lossless casting. Our aim is to lay the foundation for a practical verification system that is precise, concise and modular for sequential OO programs. We exploit the separation logic formalism to achieve this.