High level compilation for gate reconfigurable architectures

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (p. 205-215).A continuing exponential increase in the number of programmable elements is turning management of gate-reconfigurable architectures as "glue logic" into an intractable problem; it is past time to raise this abstraction level. The physical hardware in gate-reconfigurable architectures is all low level - individual wires, bit-level functions, and single bit registers - hence one should look to the fetch-decode-execute machinery of traditional computers for higher level abstractions. Ordinary computers have machine-level architectural mechanisms that interpret instructions - instructions that are generated by a high-level compiler. Efficiently moving up to the next abstraction level requires leveraging these mechanisms without introducing the overhead of machine-level interpretation. In this dissertation, I solve this fundamental problem by specializing architectural mechanisms with respect to input programs. This solution is the key to efficient compilation of high-level programs to gate reconfigurable architectures. My approach to specialization includes several novel techniques. I develop, with others, extensive bitwidth analyses that apply to registers, pointers, and arrays. I use pointer analysis and memory disambiguation to target devices with blocks of embedded memory. My approach to memory parallelization generates a spatial hierarchy that enables easier-to-synthesize logic state machines with smaller circuits and no long wires.(cont.) My space-time scheduling approach integrates the techniques of high-level synthesis with the static routing concepts developed for single-chip multiprocessors. Using DeepC, a prototype compiler demonstrating my thesis, I compile a new benchmark suite to Xilinx Virtex FPGAs. Resulting performance is comparable to a custom MIPS processor, with smaller area (40 percent on average), higher evaluation speeds (2.4x), and lower energy (18x) and energy-delay (45x). Specialization of advanced mechanisms results in additional speedup, scaling with hardware area, at the expense of power. For comparison, I also target IBM's standard cell SA-27E process and the RAW microprocessor. Results include sensitivity analysis to the different mechanisms specialized and a grand comparison between alternate targets.by Jonathan William Babb.Ph.D

Functional programming, program transformations and compiler construction

Dit proefschrift handelt over het ontwerp van de compilergenerator Elegant. Een compiler generator is een computer programma dat vanuit een speci??catie een compiler kan genereren. Een compiler is een computer programma dat een gestructureerde invoertekst kan vertalen in een uitvoertekst. Een compiler generator is zelf een compiler welke de speci??catie vertaalt in de programmatekst van de gegenereerde compiler. Dit heeft het mogelijk gemaakt om Elegant met zichzelf te genereren. Van een compilergenerator wordt verlangd dat deze een krachtig speci??catie formalisme vertaalt in een eÆci??ent programma, een eis waar Elegant aan voldoet. Een compiler bestaat uit een aantal onderdelen, te weten een scanner, een parser, een attribuutevaluator, een optimalisator en een codegenerator. Deze onderdelen kunnen door het Elegant systeem geneneerd worden, ieder uit een aparte speci??catie, met uitzondering van de parser en attribuutevaluator, welke gezamenlijk worden beschreven in de vorm van een zogenaamde attribuutgrammatica. De scanner wordt gegenereerd met behulp van een scannergenerator en heeft tot taak de invoertekst te splitsen in een rij symbolen. Deze rij symbolen kan vervolgens ontleed worden door een parser. Daarna berekent de attribuutevaluator eigenschappen van de invoertekst in de vorm van zogenaamde attributen. De attributenwaarden vormen een datastructuur. De vorm van deze datastructuur wordt gede??nieerd met behulp van typeringsregels in de Elegant programmeertaal. De optimalisator en codegenerator voeren operaties op deze datastructuur uit welke eveneens beschreven worden in de Elegant programmeertaal. Dit proefschrift beschrijft de invloed die functionele programmeertalen hebben gehad op het ontwerp van Elegant. Functionele talen zijn programmeertalen met als belangrijkste eigenschap dat functies een centrale rol vervullen. Functies kunnen worden samengesteld tot nieuwe functies, ze kunnen worden doorgegeven aan functies en worden opgeleverd als functieresultaat. Daarnaast staan functionele talen niet toe dat de waarde van een variable wordt gewijzigd, het zogenaamde nevene??ect, in tegenstelling tot imperatieve talen die zo'n nevene??ect wel toestaan. Deze laatste beperking maakt het mogelijk om met behulp van algebra??ische regels een functioneel programma te herschrijven in een ander functioneel programma met dezelfde betekenis. Dit herschrijfproces wordt ook wel progammatransformatie genoemd. De invloed van functionele talen op Elegant omvat: ?? Het beschrijven van ontleedalgorithmen als functionele programma's. Traditioneel worden ontleedalgorithmen beschreven met behulp van de theorie van stapelautomaten. In hoofdstuk 3 wordt aangetoond dat deze theorie niet nodig is. Met behulp van programmatransformaties zijn vele uit de literauur bekende ontleedalgorithmen af te leiden en worden ook nieuwe ontleedalgorithmen gevonden. Deze aanpak maakt het bovendien mogelijk om de vele verschillende ontleedalgorithmen met elkaar te combineren. ?? De evaluatie van attributen volgens de regels van een attribuutgrammatica blijkt eveneens goed te kunnen worden beschreven met behulp van functionele talen. Traditioneel bouwt een ontleedalgorithme tijdens het ontleden een zogenaamde ontleedboom op. Deze ontleedboom beschrijft de structuur van de invoertekst. Daarna wordt deze ontleedboom geanalyseerd en worden eigenschappen ervan in de vorm van attributen berekend. In hoofdstuk 4 van het proefschrift wordt aangetoond dat het niet nodig is de ontleedboom te construeren. In plaats daarvan is het mogelijk om tijdens het ontleden functies die attributen kunnen berekenen samen te stellen tot nieuwe functies. Uiteindelijk wordt er zo ??e??en functie geconstrueerd voor een gehele invoertekst. Deze functie wordt vervolgens gebruikt om de attribuutwaarden te berekenen. Voor de uitvoering van deze functie is het noodzakelijk gebruik te maken van zogenaamde "luie evaluatie". Dit is een mechanisme dat attribuutwaarden slechts dan berekent wanneer deze werkelijk noodzakelijk zijn. Dit verklaart de naam Elegant, welke een acroniem is voor "Exploiting Lazy Evaluation for the Grammar Attributes of Non- Terminals". ?? Scanners worden traditioneel gespeci??ceerd met behulp van zogenaamde reguliere expressies. Deze reguliere expressies kunnen worden afgebeeld op een eindige automaat. Met behulp van deze automaat kan de invoertekst worden geanalyseerd en gesplitst in symbolen. In hoofdstuk 5 wordt uiteengezet hoe functionele talen het mogelijk maken om scanneralgorithmen te construeren zonder gebruik te maken van automatentheorie. Door een reguliere expressie af te beelden op een functie en de functies voor de onderdelen van samengestelde reguliere expressies samen te stellen tot nieuwe functies kan een scannerfunctie geconstrueerd worden. Door gebruik te maken van programmatransformaties kan deze scanner deterministisch worden gemaakt en minimaal worden gehouden. ?? Het typeringssysteem van Elegant wordt beschreven in hoodstuk 6 en vormt een combinatie van systemen die in functionele en imperatieve talen worden gevonden. Functionele typeringssystemen omvatten typen welke bestaan uit een aantal varianten. Elk van deze varianten bestaat uit een aantal waarden. Bij een dergelijk typeringssysteem wordt een functie gede??ni??eerd door middel van een aantal deeelfuncties. Elke deelfunctie kan met behulp van zogenaamde patronen beschrijven voor welke van de varianten hij gede??ni??eerd is. Het blijkt dat imperatieve typesystemen welke subtypering mogelijk maken een generalisatie zijn van functionele typesystemen. In deze generalisatie kan een patroon worden opgevat als een subtype en een deelfunctie als een parti??ele functie. Het Elegant typesystemen maakt deze vorm van typering en functiebeschrijving mogelijk. Bij toepassing van een functie wordt de bijbehorende deelfunctie geselecteerd door de patronen te passen met de waarden van de actuele functieargumenten. In dit proefschrift wordt een eÆci??ent algorithme voor dit patroonpassen met behulp van programmatransformaties afgeleid uit de de??nitie van patronen. Het Elegant typeringssystemen bevat ook typen voor de modellering van luie evaluatie. De aanwezigheid van nevene??ekten maakt het mogelijk om drie verschillende luie typen te onderscheiden, welke verschillen in de wijze waarop de waarde van een lui object stabiliseert. ?? In hoofdstuk 7 wordt aangetoond dat de regels uit een attribuutgrammatica ook kunnen worden gebruikt om eigenschappen van een datastructuur te berekenen in plaats van eigenschappen van een invoertekst. Elegant biedt de mogelijkheid om zulke attribuutregels te gebruiken voor dit doel. ?? In hoofdstuk 8 tenslotte worden de Elegant programmeertaal en de eÆci??entie van de Elegant vertaler en door Elegant gegenereerde vertalers ge??evalueerd. Het blijkt dat de imperatieve Elegant programmeertaal dankzij abstractie mechanismen uit functionele talen een zeer rijke en krachtige taal is. Daarnaast zijn zowel Elegant zelf als de door Elegant gegenereerde vertalers van hoge eÆci??entie en blijken geschikt voor het maken van compilers voor professionele toepassingen

Compiling Logical Features into Specialized State-Evaluators by Partial Evaluation, Boolean Tables and Incremental Calculation

. A good evaluation function is needed for a good game program, and good features, which are primitive metrics of a state, are needed for a good evaluation function. In order to obtain good features, automatic generation of features by machine learning is promising. However, the generated features are usually written in logic programs, whose evaluation is much slower than that of other native expressions due to the interpretive evaluation of the logic programs. In order to solve this problem, we propose a method which constructs a specialized evaluator using a combination of techniques: partial evaluation, Boolean tables, and incremental calculation. It exhaustively unfolds logical programs until they can be represented as simple Boolean tables. The constructed specialized evaluator is ecient since it consults only these compiled tables. Experiments with Othello showed that speed can be increased approximately 2,000 times. 1 Introduction 1.1 Evaluation Function and Featu..

Compiling Logical Features into Specialized State-Evaluators by Partial Evaluation, Boolean Tables and Incremental Calculation

Abstract. A good evaluation function is needed for a good game program, and good features, which are primitive metrics of a state, are needed for a good evaluation function. In order to obtain good features, automatic generation of features by machine learning is promising. However, the generated features are usually written in logic programs, whose evaluation is much slower than that of other native expressions due to the interpretive evaluation of the logic programs. In order to solve this problem, we propose a method which constructs a specialized evaluator using a combination of techniques: partial evaluation, Boolean tables, and incremental calculation. It exhaustively unfolds logical programs until they can be represented as simple Boolean tables. The constructed specialized evaluator is efficient since it consults only these compiled tables. Experiments with Othello showed that speed can be increased approximately 2,000 times.

DYNAMIC LANGUAGE UPDATING

With respect to traditional systems, language interpreters are hard to evolve and the adoption of evolved languages is slow. Language evolution is hindered by the fact that their implementations often overlook design principles, especially those related to modularity. Consequently, language implementations and their updates are monolithic. Language evolution often breaks the backward compatibility and requires developers to rewrite their applications. Furthermore, there is little or no support to evolve language interpreters at runtime. This would be useful for systems that cannot be shut down and to support context-aware interpreters. To tackle these issues, we designed the concept of open interpreters which provide support for language evolution through reflection. Open interpreters allow one to partially update a language to maintain the backward compatibility. Furthermore, they allow one to dynamically update a language without stopping the overlying application. Open interpreters can be dynamically tailored on the task to be solved. The peculiarity of this approach is that the evolution code is completely separated from the application or the original interpreter code. In this dissertation we define the concept of open interpreters, we design a possible implementation model, we describe a prototype implantation and provide the proof-of-concept examples applied to various domains

Automated Black Box Generation of Structured Inputs for Use in Software Testing

A common problem in automated software testing is the need to generate many inputs with complex structure in a black-box fashion. For example, a library for manipulating red-black trees may require that inputs are themselves valid red-black trees, meaning anything invalid is not suitable for testing. As another example, in order to test code generation in a compiler, it is necessary to use input programs which are both syntactically valid and well-typed. Despite the importance of this problem, we observe that existing solutions are few in number and have severe drawbacks, including unreasonably slow performance and a lack of generality to testing different systems.This thesis presents a solution to this problem of black-box structured input generation. I observe that test inputs can be described as solutions to systems of logical constraints, and that more expressive constraints can lead to more complex tests. In order to test effectively and generate many tests, we need high-performance constraint solvers capable of finding many solutions to these constraints. I observe that constraint logic programming (CLP) offers an expressive constraint language paired with a high-performance constraint solver, and thus serves as a potential solution to this problem. Via a series of case studies, I have found that CLP (1) is applicable to testing a wide variety of systems; (2) can scale to more complex constraints than ever previously described; and (3) is often orders of magnitude faster than competing solutions. These case studies have also exposed dozens of bugs in high-profile software, including the Rust compiler and the Z3 SMT solver

Use and Evaluation of Controlled Languages in Industrial Environments and Feasibility Study for the Implementation of Machine Translation

El presente trabajo de investigación se enmarca en los estudios de doctorado en traducción y la sociedad del conocimiento de la Universidad de Valencia y, en concreto, en la línea de investigación en tecnologías de la traducción, terminología y localización. En este sentido, esta disertación surge por la necesidad de establecer una metodología de investigación y ofrecer resultados empíricos sobre el desarrollo, implementación y evaluación de lenguajes controlados en la documentación técnica y su efecto tanto en los textos originales como en las traducciones de estos documentos. Así pues, el objetivo ha sido desarrollar una metodología para evaluar el impacto de los lenguajes controlados en la producción de documentación técnica dentro de contextos industriales y, más en concreto, en la elaboración de documentación técnica para el vehículo. El impacto se ha concretado en la mejora de la traducibilidad automática, un concepto que hemos discutido ampliamente en el capítulo 4, así como de la calidad de los textos meta.This research is part of the doctoral studies program "La traducción y la sociedad del conocimiento" at the University of Valencia. In particular the area of ​​research is translation technology, terminology and localisation. In this sense, this dissertation arises from the need to establish a research methodology and to provide empirical results on the development, implementation and evaluation of controlled languages ​​in the technical documentation and its effect on both original texts and the translations of these documents. Thus, the aim has been to develop a methodology to assess the impact of controlled languages ​​in the production of technical documentation in industrial contexts, and more specifically in the technical documentation for the vehicle. The impact has resulted in improved automatic translatability, a concept we have discussed at length in Chapter 4, as well as in the quality of the target texts

An illumination of the template enigma : software code generation with templates

Creating software is a process of refining a concept to an implementation. This process consists of several stages represented by documents, models and plans at several levels of abstraction. Mostly, the refinement process requires creativity of the programmers, but sometimes the task is boring and repetitive. This repetitive work is an indication that the program is not written at the most suitable level of abstraction. The level of abstraction offered by the used programming language might be too low to remove the recurring code. Code generators can be used to raise the level of abstraction of program specifications and to automate the repetitive work. This thesis focuses on code generators based on templates. Templates are one of the techniques to implement a code generator. Templates allow extension of the syntax of a programming language, enabling generative programming without modifying the underlying compiler. Four artifacts are involved in a template based generator: templates, input data, a template evaluator and output code. The templates we consider are a concrete (incomplete) representation of the output document, i.e. object code, that contains holes, i.e. the meta code. These holes are filled by the template evaluator using information from the input data to obtain the output code. Templates are widely used to generate HTML code in web applications. They can be used for generating all kinds of text, like e-mails or (source) code. In this thesis we limit the scope to the generation of source code. The central research question is how the quality of template based code generators can be improved. Quality, in general, is a broad notion and our scope is limited to the technical quality of templates and generated code. We focused on improving the maintainability of template based code generators and the correctness of the generated code. This is facilitated by the three main contributions provided by this thesis. First, the maintainability of template based code generators is increased by specifying the following requirement for our metalanguage. Our metalanguage should not be rich enough to allow programming in templates, without being too restrictive to express some code generators. We used the theory of formal languages to specify our metalanguage. Second, we ensure correctness of the templates and generated code. Third, the presented theory and techniques are validated by case studies. These case studies show application of templates in real world applications, increased maintainability and syntactical correctness of generated code. Our metalanguage should not be rich enough to allow programming in templates, without being too restrictive to express some code generators. The theory of formal languages is used to specify the requirements for our metalanguage. As we only consider to generate programming languages, it is sufficient to support the generation of languages defined by context-free grammars. This assumption is used to derive a metalanguage, that is rich enough to specify code generators that are able to instantiate all possible sentences of a context-free language. A specific case of a code generator, the unparser, is a program that can instantiate all sentences of a context-free language. We proved that an unparser can be implemented using a linear deterministic topdown tree-to-string transducer. We call this property unparser-completeness. Our metalanguage is based on a linear deterministic top-down tree-to-string transducer. Recall that the goal of specifying the requirements of the metalanguage is to increase the maintainability of template based code generators, without being too restrictive. To validate that our metalanguage is not too restrictive and leads to better maintainable templates, we compared it with four off-the-shelf text template systems by implementing an unparser. We have observed that the industrial template evaluators provide a Turing complete metalanguage, but they do not contain a block scoping mechanism for the meta-variables. This results in undesired additional boilerplate meta code in their templates. The second contribution is guaranteeing the correctness of the generated code. Correctness of the generated code can be divided in two concerns: syntactical correctness and semantical correctness. We start with syntactical correctness of the generated code. The use of text templates implies that syntactical correctness of the generated code can only be detected at compilation time. This means that errors detected during the compilation are reported on the level of the generated code. The developer is required to trace back manually the errors to their origin in the template or input data. We believe that programs manipulating source code should not consider the object code as text to detect errors as early as possible. We present an approach where the grammars of the object language and metalanguage can be combined in a modular way. Combining both grammars allows parsing both languages simultaneously. Syntax errors in both languages of the template will be found while parsing it. Moreover, only parsing a template is not sufficient to ensure that the generated code will be free of syntax errors. The template evaluator must be equipped with a mechanism to guarantee its output will be syntactically correct. We discuss our mechanism in short. A parse tree is constructed during the parsing of the template. This tree contains subtrees for the object code and subtrees for the meta code. While evaluating the template, subtrees of the meta code are substituted by object code subtrees. The template evaluator checks whether the root nonterminal of the object code subtree is equal to the root nonterminal of the meta code subtree. When both are equal, it is allowed to substitute the meta code. When the root nonterminals are distinct an accurate error message is generated. The template evaluator terminates when all meta code subtrees are substituted. The result is a parse tree of the object language and thus syntactically correct. We call this process syntax safe code generation. In order to validate that the presented techniques increase maintainability and ensure syntactical correctness, we implemented our ideas in a syntax safe template evaluator called Repleo. Repleo has been applied in four case studies. The first case is a real world situation, where it is required to generate a three tier web application from a data model. This case showed that multiple layers of an applications defined in different programming languages can be generated from a single model. The second case and third case are used to show that our metalanguage results in a better maintainable code generator. Our metalanguage forces to use a two layer code generator with separation of concerns between the two layers, where the original implementations are less modular. The last case study shows that ensuring syntactical correctness results in the prevention of cross-site scripting attacks in dynamic generation of web pages. Recall that one of our goals was ensuring the correctness of the generated code. We also showed that is possible to check static semantic properties of templates. Static semantic checks are defined for the metalanguage, for the object language and checks for the situations where the object language is dependent on the metalanguage. We implemented a prototype of a static semantic checker for PicoJava templates using attribute grammars. The use of attribute grammars leads to re-use of the original PicoJava checker. Summarizing, in this thesis we have formulated the requirements for a metalanguage and discussed how to implement a syntax safe template evaluator. This results in better maintainable template based code generators and more reliable generated code

OO-IP hybrid language design and a framework approach to the GIPC

Intensional Programming is a declarative programming paradigm in which expressions are evaluated in an inherently multidimensional context space. The Lucid family of programming languages is, to this day, the only programming languages of true intensional nature. Lucid being a functional language, Lucid programs are inherently parallel and their parallelism can be efficiently exploited by the adjunction of a procedural language to increase the granularity of its parallelism, forming hybrid Lucid languages. That very wide array of possibilities raises the need for an extremely flexible programming language investigation platform to investigate on this plethora of possibilities for Intensional Programming. That is the purpose of the General Intensional Programming System (GIPSY), especially, the General Intensional Programming Compiler (GIPC) component. The modularity, reusability and extensibility aspects of the framework approach make it an obvious candidate for the development of the GIPC. The framework presented in this thesis provides a better solution compared to all other techniques used to this day to implement the different variants of intensional programming. Because of the functionality of hybrid programming support in the GIPC framework, a new OO-IP hybrid language is designed for further research. This new hybrid language combines the essential characteristics of IPL and Java, and introduces the notion of object streams which makes it is possible that each element in an IPL stream could be an object with embedded intensional properties. Interestingly, this hybrid language also brings to Java objects the power which can explicitly express context, creating the novel concept of intensional objects, Le. objects whose evaluation is context-dependent, which are therein demonstrated to be translatable into standard objects. By this new feature, we extend the use and meaning of the notion of object and enrich the meaning of stream in IPL and semantics of Java. At the same time, during the procedure to introduce intensional objects and this OO-IP hybrid language, many factors are considered. These factors include how to integrate the new language with the GIPC framework design and the issues related to its integration in the current GIPSY implementation. Current semantic rules show that the new language can work well with the GIPC framework and the GIPSY implementation, which is another proof of the validity of our GIPC framework design. Ultimately, the proposed design is put into implementation in the GIPSY and the implementation put to test using programs from different application domains written in this new OO-IP languag

Identifying evidences of computer programming skills through automatic source code evaluation

Orientador: Roberto PereiraCoorientador: Eleandro MaschioTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa : Curitiba, 27/03/2020Inclui referências: p. 98-106Área de concentração: Ciência da ComputaçãoResumo: Esta tese e contextualizada no ensino de programacao de computadores em cursos de Computacao e investiga aspectos e estrategias para avaliacao automatica e continua de codigos fonte desenvolvidos pelos alunos. O estado da arte foi identificado por meio de revisao sistematica de literatura e revelou que as pesquisas anteriores tendem a realizar avaliacoes baseadas em aspectos tecnicos de codigos fonte, como a avaliacao de corretude funcional e a deteccao de erros. Avaliacoes baseadas em habilidades, por outro lado, sao pouco exploradas e possuem potencial para fornecer detalhes a respeito de habilidades representadas por conceitos de alto nivel, como desvios condicionais e estruturas de repeticao. Um metodo de identificacao automatica de evidencias de aprendizado e entao proposto como uma abordagem baseada em habilidades para a avaliacao automatica de codigos fonte de programacao. O metodo e caracterizado pela implementacao de diferentes estrategias para avaliacao de codigos fonte, identificacao de evidencias de habilidades de programacao, e representacao destas habilidades em um modelo do aluno. Experimentos realizados em ambientes controlados (bases de dados artificiais) mostraram que estrategias automaticas de avaliacao de codigo fonte sao viaveis. Experimentos conduzidos em ambientes reais (codigos fonte produzidos por alunos) produziram resultados semelhantes aos ambientes controlados, entretanto revelaram limitacoes relacionadas a implementacao das estrategias, como vulnerabilidades a sintaxes inesperadas e falhas em expressoes regulares. Um conjunto de habilidades foi selecionado para compor o modelo do aluno, representado por uma rede bayesiana dinamica. Por meio de experimentos foi demonstrado que a alimentacao do modelo com evidencias resultantes da avaliacao automatica de codigos fonte permite o acompanhamento do progresso das habilidades dos alunos. Finalmente, as estrategias automaticas em conjunto com os recursos do modelo do aluno permitiram a demonstracao da avaliacao baseada em habilidades, que se mostrou um recurso valioso para identificacao de solucoes funcionalmente corretas, porem conceitualmente incorretas; quando o programa e funcionalmente correto, retornando resultados esperados a determinadas entradas, porem foi construido com recursos e conceitos incorretos. Palavras-chave: Programacao de Computadores, Avaliacao Automatica, Avaliacao Baseada em HabilidadesAbstract: This thesis is contextualized in the teaching of computer programming in Computing courses and investigates aspects and strategies for automatic and continuous evaluation of student developed source codes. The state of the art was identified through systematic literature review and revealed previous research tends to perform evaluations based on source codes technical aspects, such as functional correctness assessment and error detection. Skills-based assessments, in turn, are less explored although having potential to provide details of skills represented by high-level concepts, such as conditionals and repetition structures. A method for automatic identification of learning evidences is then proposed as a skills-based approach to automatic evaluation of programming source codes. The method is characterized by implementing different strategies for source code evaluation, identifying evidences of programming skills, and representing these skills in a student model. Experiments conducted in controlled scenarios (testing datasets) have shown automatic source code evaluation strategies are viable. Experiments conducted in real scenarios (student-made source codes) produced results similar to controlled scenarios, however, implementation-related limitations were revealed for some strategies, such as vulnerabilities to unexpected syntax and flaws in regular expressions. A skill set was selected to compose our student model, represented by a Dynamic Bayesian Network. Experiments have shown feeding the model with evidences resulting from source codes automatic evaluation allows monitoring students' skills progress. Finally, automatic strategies coupled with student model capabilities enabled demonstrating skills-based assessment, which showed a valuable resource for identifying functionally correct source codes, but conceptually incorrect; when a program is correct functionally, returning expected results to specific inputs, but it was built with erroneous concepts and resources. Keywords: Computer Programming, Automatic Evaluation, Skills-Based Assessmen