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RegionBased Memory Management
, 1997
"... This paper describes a memory management discipline for programs that perform dynamic memory allocation and deallocation. At runtime, all values are put into regions. The store consists of a stack of regions. All points of region allocation and deallocation are inferred automatically, using a type ..."
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Cited by 280 (8 self)
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This paper describes a memory management discipline for programs that perform dynamic memory allocation and deallocation. At runtime, all values are put into regions. The store consists of a stack of regions. All points of region allocation and deallocation are inferred automatically, using a type and effect based program analysis. The scheme does not assume the presence of a garbage collector. The scheme was first presented by Tofte and Talpin (1994); subsequently, it has been tested in The ML Kit with Regions, a regionbased, garbagecollection free implementation of the Standard ML Core language, which includes recursive datatypes, higherorder functions and updatable references (Birkedal et al. 96, Elsman and Hallenberg 95). This paper defines a regionbased dynamic semantics for a skeletal programming language extracted from Standard ML. We present the inference system which specifies where regions can be allocated and deallocated and a detailed proof that the system is sound wi...
The Type and Effect Discipline
 Information and Computation
, 1992
"... The type and effect discipline is a new framework for reconstructing the principal type and the minimal effect of expressions in implicitly typed polymorphic functional languages that support imperative constructs. The type and effect discipline outperforms other polymorphic type systems. Just as ty ..."
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Cited by 152 (3 self)
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The type and effect discipline is a new framework for reconstructing the principal type and the minimal effect of expressions in implicitly typed polymorphic functional languages that support imperative constructs. The type and effect discipline outperforms other polymorphic type systems. Just as types abstract collections of concrete values, effects denote imperative operations on regions. Regions abstract sets of possibly aliased memory locations. Effects are used to control type generalization in the presence of imperative constructs while regions delimit observable sideeffects. The observable effects of an expression range over the regions that are free in its type environment and its type; effects related to local data structures can be discarded during type reconstruction. The type of an expression can be generalized with respect to the variables that are not free in the type environment or in the observable effect. 1 Introduction Type inference [12] is the process that automa...
Polymorphic Type, Region and Effect Inference
, 1991
"... We present a new static system that reconstructs the types, regions and effects of expressions in an implicitly typed functional language that supports imperative operations on reference values. Just as types structurally abstract collections of concrete values, regions represent sets of possibly a ..."
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Cited by 121 (6 self)
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We present a new static system that reconstructs the types, regions and effects of expressions in an implicitly typed functional language that supports imperative operations on reference values. Just as types structurally abstract collections of concrete values, regions represent sets of possibly aliased reference values and effects represent approximations of the imperative behavior on regions. We introduce a static semantics for inferring types, regions and effects and prove that it is consistent with respect to the dynamic semantics of the language. We present a reconstruction algorithm that computes the types and effects of expressions and assigns regions to reference values. We prove the correctness of the reconstruction algorithm with respect to the static semantics. Finally, we discuss potential applications of our system to automatic stack allocation and parallel code generation.
Equivalence in Functional Languages with Effects
, 1991
"... Traditionally the view has been that direct expression of control and store mechanisms and clear mathematical semantics are incompatible requirements. This paper shows that adding objects with memory to the callbyvalue lambda calculus results in a language with a rich equational theory, satisfying ..."
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Cited by 111 (13 self)
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Traditionally the view has been that direct expression of control and store mechanisms and clear mathematical semantics are incompatible requirements. This paper shows that adding objects with memory to the callbyvalue lambda calculus results in a language with a rich equational theory, satisfying many of the usual laws. Combined with other recent work this provides evidence that expressive, mathematically clean programming languages are indeed possible. 1. Overview Real programs have effectscreating new structures, examining and modifying existing structures, altering flow of control, etc. Such facilities are important not only for optimization, but also for communication, clarity, and simplicity in programming. Thus it is important to be able to reason both informally and formally about programs with effects, and not to sweep effects either to the side or under the store parameter rug. Recent work of Talcott, Mason, Felleisen, and Moggi establishes a mathematical foundation for...
The Marriage of Effects and Monads
, 1998
"... this paper is to marry effects to monads, writing T for a computation that yields a value in and may have effects delimited by oe. Now we have that ( is ..."
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Cited by 92 (4 self)
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this paper is to marry effects to monads, writing T for a computation that yields a value in and may have effects delimited by oe. Now we have that ( is
From Region Inference to von Neumann Machines via Region Representation Inference
 IN TWENTYTHIRD ACM SYMPOSIUM ON PRINCIPLES OF PROGRAMMING LANGUAGES
, 1996
"... Region Inference is a technique for implementing programming languages that are based on typed callbyvalue lambda calculus, such as Standard ML. The mathematical runtime model of region inference uses a stack of regions, each of which can contain an unbounded number of values. This paper is concer ..."
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Cited by 89 (8 self)
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Region Inference is a technique for implementing programming languages that are based on typed callbyvalue lambda calculus, such as Standard ML. The mathematical runtime model of region inference uses a stack of regions, each of which can contain an unbounded number of values. This paper is concerned with mapping the mathematical model onto real machines. This is done by composing region inference with Region Representation Inference, which gradually refines region information till it is directly implementable on conventional von Neumann machines. The performance of a new regionbased ML compiler is compared to the performance of Standard ML of New Jersey, a stateoftheart ML compiler.
Once Upon a Type
 In Functional Programming Languages and Computer Architecture
, 1995
"... A number of useful optimisations are enabled if we can determine when a value is accessed at most once. We extend the HindleyMilner type system with uses, yielding a typeinference based program analysis which determines when values are accessed at most once. Our analysis can handle higherorder fun ..."
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Cited by 81 (2 self)
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A number of useful optimisations are enabled if we can determine when a value is accessed at most once. We extend the HindleyMilner type system with uses, yielding a typeinference based program analysis which determines when values are accessed at most once. Our analysis can handle higherorder functions and data structures, and admits principal types for terms. Unlike previous analyses, we prove our analysis sound with respect to callbyneed reduction. Callbyname reduction does not provide an accurate model of how often a value is used during lazy evaluation, since it duplicates work which would actually be shared in a real implementation. Our type system can easily be modified to analyse usage in a callbyvalue language. 1 Introduction This paper describes a method for determining when a value is used at most once. Our method is based on a simple modification of the HindleyMilner type system. Each type is labelled to indicate whether the corresponding value is used at most onc...
Practical Dynamic Software Updating
, 2008
"... This dissertation makes the case that programs can be updated while they run, with modest programmer effort, while providing certain update safety guarantees, and without imposing a significant performance overhead. Few systems are designed with onthefly updating in mind. Those systems that permit ..."
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Cited by 77 (28 self)
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This dissertation makes the case that programs can be updated while they run, with modest programmer effort, while providing certain update safety guarantees, and without imposing a significant performance overhead. Few systems are designed with onthefly updating in mind. Those systems that permit it support only a very limited class of updates, and generally provide no guarantees that following the update, the system will behave as intended. We tackle the onthefly updating problem using a compilerbased approach called dynamic software updating (DSU), in which a program is patched with new code and data while it runs. The challenge is in making DSU practical: it should support changes to programs as they occur in practice, yet be safe, easy to use, and not impose a large overhead. This dissertation makes both theoretical contributions—formalisms for reasoning about, and ensuring update safety—and practical contributions—Ginseng, a DSU implementation for C. Ginseng supports a broad range of changes to C programs, and performs a suite of safety analyses to ensure certain update safety
MJ: An imperative core calculus for Java and Java with effects
, 2003
"... In order to study rigorously objectoriented languages such as Java or C , a common practice is to define lightweight fragments, or calculi, which are sufficiently small to facilitate formal proofs of key properties. However many of the current proposals for calculi lack important language features. ..."
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Cited by 62 (8 self)
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In order to study rigorously objectoriented languages such as Java or C , a common practice is to define lightweight fragments, or calculi, which are sufficiently small to facilitate formal proofs of key properties. However many of the current proposals for calculi lack important language features. In this paper we propose Middleweight Java, MJ, as a contender for a minimal imperative core calculus for Java. Whilst compact, MJ models features such as object identity, field assignment, constructor methods and block structure. We define the syntax, type system and operational semantics of MJ, and give a proof of type safety. In order to demonstrate the usefulness of MJ to reason about operational features, we consider a recent proposal of Greenhouse and Boyland to extend Java with an effects system. This effects system is intended to delimit the scope of computational effects within a Java program. We define an extension of MJ with a similar effects system and instrument the operational semantics. We then prove the correctness of the effects system
Implementation of the typed callbyvalue λcalculus using a stack of regions
 In ACM Symposium on Principles of Programming Languages
, 1994
"... We present a translation scheme for the polymorphically typed callbyvalue λcalculus. All runtime values, including function closures, are put into regions. The store consists of a stack of regions. Region inference and effect inference are used to infer where regions can be allocated and dealloc ..."
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Cited by 57 (0 self)
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We present a translation scheme for the polymorphically typed callbyvalue λcalculus. All runtime values, including function closures, are put into regions. The store consists of a stack of regions. Region inference and effect inference are used to infer where regions can be allocated and deallocated. Recursive functions are handled using a limited form of polymorphic recursion. The translation is proved correct with respect to a store semantics, which models a regionbased runtime system. Experimental results suggest that regions tend to be small, that region allocation is frequent and that overall memory demands are usually modest, even without garbage collection. 1