Introduction Connecting Architecture There is a wealth of - - PowerPoint PPT Presentation

Connecting Architecture Reconstruction Frameworks

Ivan Bowman, Michael Godfrey, Ric Holt

Software Architecture Group University of Waterloo CoSET ‘99

May 17, 1999

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Introduction

• There is a wealth of re-engineering tools
• Often, we would like to combine these
• Differences in tool storage formats and

semantics makes reuse difficult

• We defined an exchange format that can be

used to combine several tools:

– CIAO, Dali, Datrix, PBS, and Rigi

Introduction

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Background

• Recent work within CSER has identified
• pportunities for re-use between tools
• We identified two levels of tools:

– Code-Level tools provide detailed support – Architecture-Level tools identify high-level abstractions

• We describe a format for connecting

architecture-level tools

Introduction

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Architectural Reconstruction

Introduction

Source Code Executing System Source Control

System Artifacts

Scanning Parsing Profiling Change Reporting

Extractors

Extracted Facts

Repository View Generation

Visualization Manipulation Architecture

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Entity-Relational Model

• Entities represent source code elements

such as functions, variables, or types

• Relations represent associations in source

code such as calls or inheritance

• Attributes such as line-number record

additional information

• A Schema defines the allowed entities,

relations, and attributes

Model

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Example Schema

Model

Function

line number

Variable

line number references line number calls line number

Module

• wner

contains contains

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Connection Format Requirements

• Support multiple source languages
• Scale to large systems (e.g. 10 MLOC)
• Provide mapping to source code
• Support static and dynamic dependencies
• Incremental approach
• Must be extensible, allowing new schemes

to be defined as needed

Requirements

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The Naming Problem

• Each entity must have unique ID
• Source languages may allow two code

elements to have the same name

– typedef int T; – struct T { ... };

• To combine facts, we need a common naming scheme
• We have defined a scheme for Java, and we

are discussing possible solutions for C,C++

Problems

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The Line-Number Problem

• We require a mechanism to get from an

entity back to source code

• An obvious solution is to store file + line #

– We want same file name on different machines – Some entities are defined on a range of lines, or non-contiguous ranges of lines (for example, namespaces)

Problems

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The Resolution Problem

• For each reference in source code, we can

determine the reference target

• Several resolution strategies are used:

– No resolution - each reference is an entity – Resolved to declaration (in a header file) – Resolved to static definition (entity body) – Resolved to dynamic definition (virtual functions, pointers)

Problems

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TAXForm

• Idea: provide converters between tool-

specific formats and a common format

• There are two parts to an exchange format:

– Syntax of data (representation in files) – Semantic structure (schemas)

• We chose TA syntax (others are attractive)
• We allow tool developers to define their
• wn schemas as needed

TAXForm

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Transforming Between Schemas

TAXForm

Universal High-Level Procedural PL/I C Object-Oriented C++ Java Dali C Rigi C PBS C

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Implementing TAXForm

• We evaluated TAXForm by implementing

converters for several existing re- engineering tools

• The syntactic transformation was trivial
• We used Tarski relational algebra to specify

transformations, and executed them with grok, a relational calculator

Evaluation

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Evaluation of TAXForm

• Writing schema transformations required

careful study of semantics used by each tool

• Tools used different terminology with

different underlying assumptions

• By defining transforms between models, we

formally document all of these assumptions and provide a dictionary for terminology

Evaluation

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Systems Modeled

Evaluation

System Size Language Tool Jikes 77 KLOC C++ CIAO Linux 800 KLOC C Dali, PBS Mozilla 904 KLOC C Rigi Nachos 10 KLOC C++ CIAO

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Summary and Future Work

• We defined TAXForm as an exchange

format between architecture-level tools

• We validated our format by implementing

converters from existing tool formats

• We need to further describe the semantics
• f each model

Conclusion