Interprocedural static single assignment form in Bauhaus

In this paper we describe interprocedural static single assignment form (ISSA) with optimizations as implemented in the Bauhaus project. We explain our framework which uses an abstract program representation enabling us to use different pointer analyses ranging from fast but imprecise to slow but precise ones. Our implementation includes the computation of (may and must) side effects and optimizations like pruning definitions with simple linear-time algorithms. This paper also provides comprehensive test results and statistics for a large test suite

Compiling for parallel multithreaded computation on symmetric multiprocessors

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 145-149).by Andrew Shaw.Ph.D

General Declarative Must-Alias Analysis

Οι περισσότερες δημοσιευμένες αναλύσεις για δείκτες είναι ίσως-αναλύσεις: δηλαδή υπερεκτιμούν τη σχέση συνωνυμίας δεικτών ή τη σχέση “δείχνει-σε”. Οι αναλύσεις σίγουρης-συνωνυμίας δεικτών έχουν μελετηθεί λιγότερο αλλά προσφέρουν ελκυστικά πλεονεκτήματα, για τη βελτιστοποίηση και την κατανόηση των προγραμμάτων. Σε αυτήν την εργασία δίνουμε ένα δηλωτικό μοντέλο για μια πλούσια οικογένεια αναλύσεων σίγουρης-συνωνυμίας δεικτών. Αν και υπάρχουν ήδη στη βιβλιογραφία φορμαλισμοί ανλύσεων σίγουρης-συνωνυμίας, δίνουμε έμφαση στη μοντελοποίηση και την ανάδειξη των κύριων σημείων όπου ένας αλγόριθμος μπορεί να προσαρμόσει την ισορροπία μεταξύ της συλλογής πληροφορίας και της απόδοσης της ανάλυσης. Επιπλέον, δείχνουμε ότι το μοντέλο μας μπορεί εύκολα να επεκταθεί για να συμπεριλάβει μια ανάλυση για τη σχέση “σίγουρα-δείχνει-σε”. Το μοντέλο μας είναι εκτελέσιμο, στη γλώσσα Datalog, και αποτελεί τη βάση για μια ολοκληρωμένη ανάλυση σίγουρης-συνωνυμίας δεικτών για κώδικα σε μορφή Java bytecode. Εξετάζουμε σε βάθος πώς μπορεί να παραμετροποιηθεί η ανάλυση και ποσοτικοποιούμε την επίδραση των σχεδιαστικών αποφάσεών σε μεγάλα δοκιμαστικά προγράμματα Java.Most published pointer analysis algorithms are may-analyses: they over-approximate aliasing or points-to relations. Must-alias analyses are more rarely studied but offer at- tractive benefits, for optimization and program understanding. In this thesis we give a declarative model of a rich family of must-alias analyses. Although other specifications of must-alias algorithms exist in the literature, our emphasis is on modeling and exposing the key points where the algorithm can adjust its inference power vs. scalability trade- off. Furthermore, we show that our model can be easily extended to also incorporate a must-point-to analysis. Our model is executable, in the Datalog language, and forms the basis for a full-fledged must-alias analysis of Java bytecode. We discuss insights on con- figuring a must-alias analysis and quantify the impact of design decisions on large Java benchmarks

Lifting the Abstraction Level of Compiler Transformations

Production compilers implement optimizing transformation rules for built-in types. What justifies applying these optimizing rules is the axioms that hold for built-in types and the built-in operations supported by these types. Similar axioms also hold for user-defined types and the operations defined on them, and therefore justify a set of optimization rules that may apply to user-defined types. Production compilers, however, do not attempt to construct and apply these optimization rules to user-defined types. Built-in types together the axioms that apply to them are instances of more general algebraic structures. So are user-defined types and their associated axioms. We use the technique of generic programming, a programming paradigm to design efficient, reusable software libraries, to identify the commonality of classes of types, whether built-in or user-defined, convey the semantics of the classes of types to compilers, design scalable and effective program analysis for them, and eventually apply optimizing rules to the operations on them. In generic programming, algorithms and data structures are defined in terms of such algebraic structures. The same definitions are reused for many types, both built-in and user-defined. This dissertation applies generic programming to compiler analyses and transformations. Analyses and transformations are specified for general algebraic structures, and they apply to all types, both built-in and primitive types

Parameterized Object Sensitivity for Points-to Analysis for Java

The goal of points-to analysis for Java is to determine the set of objects pointed to by a reference variable or a reference object field. We present object sensitivity, a new form of context sensitivity for flow-insensitive points-to analysis for Java. The key idea of our approach is to analyze a method separately for each of the object names that represent runtime objects on which this method may be invoked. To ensure flexibility and practicality, we propose a parameterization framework that allows analysis designers to control the tradeo#s between cost and precision in the object-sensitive analysis

Dynamically fighting bugs : prevention, detection and elimination

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 147-160).This dissertation presents three test-generation techniques that are used to improve software quality. Each of our techniques targets bugs that are found by different stake-holders: developers, testers, and maintainers. We implemented and evaluated our techniques on real code. We present the design of each tool and conduct experimental evaluation of the tools with available alternatives. Developers need to prevent regression errors when they create new functionality. This dissertation presents a technique that helps developers prevent regression errors in object-oriented programs by automatically generating unit-level regression tests. Our technique generates regressions tests by using models created dynamically from example executions. In our evaluation, our technique created effective regression tests, and achieved good coverage even for programs with constrained APIs. Testers need to detect bugs in programs. This dissertation presents a technique that helps testers detect and localize bugs in web applications. Our technique automatically creates tests that expose failures by combining dynamic test generation with explicit state model checking. In our evaluation, our technique discovered hundreds of faults in real applications. Maintainers have to reproduce failing executions in order to eliminate bugs found in deployed programs. This dissertation presents a technique that helps maintainers eliminate bugs by generating tests that reproduce failing executions. Our technique automatically generates tests that reproduce the failed executions by monitoring methods and storing optimized states of method arguments.(cont.) In our evaluation, our technique reproduced failures with low overhead in real programs Analyses need to avoid unnecessary computations in order to scale. This dissertation presents a technique that helps our other techniques to scale by inferring the mutability classification of arguments. Our technique classifies mutability by combining both static analyses and a novel dynamic mutability analysis. In our evaluation, our technique efficiently and correctly classified most of the arguments for programs with more than hundred thousand lines of code.by Shay Artzi.Ph.D

Integrated testing and verification system for research flight software design document

The NASA Langley Research Center is developing the MUST (Multipurpose User-oriented Software Technology) program to cut the cost of producing research flight software through a system of software support tools. The HAL/S language is the primary subject of the design. Boeing Computer Services Company (BCS) has designed an integrated verification and testing capability as part of MUST. Documentation, verification and test options are provided with special attention on real time, multiprocessing issues. The needs of the entire software production cycle have been considered, with effective management and reduced lifecycle costs as foremost goals. Capabilities have been included in the design for static detection of data flow anomalies involving communicating concurrent processes. Some types of ill formed process synchronization and deadlock also are detected statically

Technical Report: Region and Effect Inference for Safe Parallelism

In this paper, we present the first full regions-and-effects inference algorithm for explicitly parallel fork-join programs. We infer annotations inspired by Deterministic Parallel Java (DPJ) for a type-safe subset of C++. We chose the DPJ annotations because they give the \emph{strongest} safety guarantees of any existing concurrency-checking approach we know of, static or dynamic, and it is also the most expressive static checking system we know of that gives strong safety guarantees. This expressiveness, however, makes manual annotation difficult and tedious, which motivates the need for automatic inference, but it also makes the inference problem very challenging: the code may use region polymorphism, imperative updates with complex aliasing, arbitrary recursion, hierarchical region specifications, and wildcard elements to describe potentially infinite sets of regions. We express the inference as a constraint satisfaction problem and develop, implement, and evaluate an algorithm for solving it. The region and effect annotations inferred by the algorithm constitute a checkable proof of safe parallelism, and it can be recorded both for documentation and for fast and modular safety checking.Ope