Ákos Kiss

Interprocedural static slicing of binary executables

Although the slicing of programs written in a high-level language has been widely studied in the literature, very little work has been published on the slicing of binary executable programs. The lack of existing solutions is really hard to understand since the application domain for slicing binaries is similar to that for slicing high-level languages. We present a method for the interprocedural static slicing of binary executables. We applied our slicing method to real size binaries and achieved an interprocedural slice size of between 56%-68%. We used conservative approaches to handle unresolved function calls and branching instructions. Our current implementation contains an imprecise (but safe) memory dependence model as well. However, this conservative slicing method might still be useful in analysing large binary programs. We suggest some improvements to eliminate useless edges from dependence graphs as well.

A formalisation of the relationship between forms of program slicing

The widespread interest in program slicing within the source code analysis and manipulation community has led to the introduction of a large number of different forms of slicing. Each preserves some aspect of a programs behaviour and simplifies the program to focus exclusively upon this behaviour. In order to understand the similarities and differences between forms of slicing, a formal mechanism is required. This paper further develops a formal framework for comparing forms of slicing using a theory of program projection. This framework is used to reveal the ordering relationship between various static, dynamic, simultaneous and conditioned forms of slicing.

Theoretical foundations of dynamic program slicing

This paper presents a theory of dynamic slicing, which reveals that the relationship between static and dynamic slicing is more subtle than previously thought. The definitions of dynamic slicing are formulated in terms of the projection theory of slicing. This shows that existing forms of dynamic slicing contain three orthogonal dimensions in their slicing criteria and allows for a lattice-theoretic study of the subsumption relationship between these dimensions and their relationship to static slicing formulations.

A novel method for the dealumination of zeolites

A wide range of halogen containing reagents (metal halides, oxyhalides, acid halides, etc.) are found to interact from the gas phase with exchange ions of zeolites and to effect dealumination at elevated temperatures. The incorporation of extraneous ions into the framework by this technique is not impossible theoretically. The importance of the method in the preparation of dealuminated and/or metal containing catalysts is discussed.AbstractЩыло найдено, что большое число реагентов, содержащих галогены (галогениды металлов, оксигалогениды, кислотные галогениды), взаимодействуют из газовой Фазы с цеолитами, приводя к обмене ионов и вытеснению алюминия. Происходящее при этом внедрение наружных ионов в решетку возможно и теоретически. Обсуждается значение метода в приготовлении катализатора без алюминия и/или катализаторов, содержащих металл.

Formalizing executable dynamic and forward slicing

This paper uses a projection theory of slicing to formalize the definition of executable dynamic and forward program slicing. Previous definitions, when given, have been operational, and previous descriptions have been algorithmic. The projection framework is used to provide a declarative formulation in terms of the different equivalences preserved by the different forms of slicing. The analysis of dynamic slicing reveals that the slicing criterion introduced by Korel and Laski contains three inter-woven criteria. It is shown how these three conceptually distinct criteria can be disentangled to reveal two new criteria. The analysis of dynamic slicing also reveals that the subsumes relationship between static and dynamic slicing is more intricate that previous authors have claimed. Finally, the paper uses the projection theory to investigate theoretical properties of forward slicing. This is achieved by first re-formulating forward slicing to provide an executable forward slice. This definition allows for formal investigation of the relationship between forward and backward slicing

Energy simulation of embedded XScale systems with XEEMU

Energy efficiency is key in embedded system design. Understanding the complex issue of software power consumption in early design phases is of extreme importance to make the right design decisions. Here, not only the CPU but also the external memory plays a very important role. Power simulators offer flexibility and allow a detailed view on the sources of power consumption. However, many simulators lack accuracy and focus only on the CPU core without considering the memory subsystem. In this paper, we present XEEMU, a fast, cycle-accurate simulator, which aims at accurately simulating the power consumption of an XScale-based system including its memory subsystem. It has been validated using measurements on real hardware and shows a high accuracy for runtime, instantaneous power, and total energy consumption estimation. The average error is as low as 3.0% and 1.6% for runtime and CPU energy consumption estimation, respectively.

XEEMU: an improved xscale power simulator

Energy efficiency is a top requirement in embedded system design. Understanding the complex issue of software power consumption in early design phases is of extreme importance to make the right design decisions. Power simulators offer flexibility and allow a detailed view on the sources of power consumption. In this paper we present XEEMU, a fast, cycle-accurate simulator, which aims at the most accurate modeling of the XScale architecture possible. It has been validated using measurements on real hardware and shows a high accuracy for runtime, instantaneous power, and total energy consumption estimation. The average error is as low as 3.0% and 1.6% for runtime and energy consumption estimation, respectively.

Investigation of NaN3 salt occlusion in the framework of Y zeolites

The interaction between sodium atoms (obtained by thermal decomposition of NaN3) and acidic OH groups of the zeolite, leading to the elimination of H+ ions, is accompanied by the occlusion of the NaN3 in the zeolitic framework. This salt occlusion process was investigated using X-ray, thermogravimetric, i.r. and visible spectroscopic methods. NaN3 occluded in the zeolite framework does not decompose at 773 K, though this temperature is higher than the decomposition temperature of the pure NaN3. It was found that nearly two N−3 ions per u.c. were occluded in the framework without destroying the crystal structure of the zeolite.

A unifying theory of control dependence and its application to arbitrary program structures

There are several similar, but not identical, definitions of control dependence in the literature. These definitions are given in terms of control flow graphs which have had extra restrictions imposed (for example, end-reachability).We define two new generalisations of non-termination insensitive and non-termination sensitive control dependence called weak and strong control-closure. These are defined for all finite directed graphs, not just control flow graphs and are hence allow control dependence to be applied to a wider class of program structures than before.We investigate all previous forms of control dependence in the literature and prove that, for the restricted graphs for which each is defined, vertex sets are closed under each if and only if they are either weakly or strongly control-closed. Low polynomial-time algorithms for producing minimal weakly and strongly control-closed sets over generalised control flow graphs are given.This paper is the first to define an underlying semantics for control dependence: we define two relations between graphs called weak and strong projections, and prove that the graph induced by a set of vertices is a weak/strong projection of the original if and only if the set is weakly/strongly control-closed. Thus, all previous forms of control dependence also satisfy our semantics. Weak and strong projections, therefore, precisely capture the essence of control dependence in our generalisations and all the previous, more restricted forms. More fundamentally, these semantics can be thought of as correctness criteria for future definitions of control dependence.

Minimal slicing and the relationships between forms of slicing

The widespread interest in program slicing within the source code analysis and manipulation community has led to the introduction of a large number of different slicing techniques. Each preserves some aspect of a programs behaviour and simplifies the program to focus exclusively upon this behaviour. In order to understand the similarities and differences between slicing techniques, a formal mechanism is required. This paper establishes a formal mechanism for comparing slicing techniques using a theory of program projection. Sets of minimal slices, which form the ideal for any slicing algorithm, are used to reveal the ordering relationship between various static and dynamic slicing techniques.