Eecient Type Inclusion Tests
نویسندگان
چکیده
A type inclusion test determines whether one type is a subtype of another. E cient type testing techniques exist for single subtyping, but not for languages with multiple subtyping. To date, the only fast constanttime technique relies on a binary matrix encoding of the subtype relation with quadratic space requirements. In this paper, we present three new encodings of the subtype relation, the packed encoding, the bit-packed encoding and the compact encoding. These encodings have di erent characteristics. The bit-packed encoding delivers the best compression rates: on average 85% for real life programs. The packed encoding performs type inclusion tests in only 4 machine instructions. We present a fast algorithm for computing these encoding which runs in less than 13 milliseconds for PE and BPE, and 23 milliseconds for CE on an Alpha processor. Finally, we compare our results with other constant-time type inclusion tests on a suite of 11 large benchmark hierarchies.
منابع مشابه
Exploiting the Induced Order on Type-Labeled Graphs for Fast Knowledge Retrieval
The graph structure of a conceptual graph can be used for eecient retrieval in complex (graphical) object databases. The aim is to replace most graph matching with eecient operations on precompiled codes for graphs. The unlabeled graph or \skeleton" of a type-labeled conceptual graph (without negated contexts) can be used as a lter for matching, subsumption testing, and uniication. For two type...
متن کاملEecient Error-propagating Block Chaining
This document presents EPBC, EEcient Error-Propagating Block Chaining, a new and eecient block encryption mode using both plaintext and ciphertext feedback. This encryption mode is similar to another one, IOBC, and was likewise designed to propagate erroneous decryptions of tampered blocks of ciphered data to all following blocks, hence allowing to validate the integrity of that data using a pr...
متن کاملPitting Initiation and Propagation of X70 Pipeline Steel Exposed to Chloride-Containing Environments
Inclusion-induced pitting initiation mechanisms in X70 steel were investigated by scanning electron microscopy, scanning Kelvin probe force microscopy (SKPFM), immersion and electrochemical polarization tests in chloride-containing ion solutions. There are three inclusion types in the X70 steel. Corrosion test results indicated that pitting corrosion resistance of type A inclusion < type C incl...
متن کاملTechniques for Speculative Run - Time Parallelization ofLoopsManish
This paper presents a set of new run-time tests for speculative parallelization of loops that defy par-allelization based on static analysis alone. It presents a novel method for speculative array privatization that is not only more eecient than previous methods when the speculation is correct, but also does not require rolling back the computation in case the variable is found not to be privat...
متن کاملAn Eecient Vlsi Architecture for Columnsort
| This paper presents novel VLSI architecture in support of an eecient implementation of Leighton's well-known Columnsort. The designs take advantage of re-conngurable bus architectures enhanced with simple shift switches. Our main contribution is to show that (1) Column-sort can be partitioned into two components of hardware scheme involving sorting arrays of small size and a hardware or softw...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 1997