Analyzing C/C++ code

Purpose

The C++ analyzer is intended to determine dependencies between C/C++ source files based on header file includes. The element hierarchy is based on the directory structure of the source code. Namespaces and types are not taken into account.

Potential ambiguity

It is important to understand that this analyzer does not have any knowledge on how to build the code and therefore does not known the include paths used during the build. It simply uses all source code directories and their nested directories as include paths.

This technique works well when source filenames are unique. It this is not the case it can be ambiguous which file is intended.

How this ambiguity is resolved can be configured:

• Ignore: Ignore dependencies which are ambiguous. Not all actual dependencies are reported in the DSM.
• AddBestMatch: Try to find the best matching file. If the algorithm gets it wrong, incorrect dependencies will be reported in the DSM.
• AddAll: Add possible choices. More than actual dependencies are reported in the DSM.

When building VC++ projects using Visual Studio selecting the Visual Studio analyzers gives more reliable results, because the actual include paths used during building are used.

Merging source and header files

A C++ module consists in most cases of a header and a source file. In many cases externally visible header files are located in a different directory the private header files or source files. For proper analysis it is better to merge them to a single location in the DSM. Three strategies are possible:

• None: The model is unchanged.
• MoveHeaderFileToSourceFile: The header file is move next to the source file with an identical name.
• MergeHeaderAndSourceFileDirectory: Entire header file directory contents is moved to a source file directory based on a configurable naming rule.

Pre requisites

• None

Performing an analysis

• Create an analyzer settings file. This can be done by:
  • Using the example below or
  • Running the analyzer with a not existing settings file. A settings file using default settings will be created.
• Edit the analyzer settings file if required:
  • Update the Input.SourceDirectories setting to point to the directory where the source code to be analyzed is located.
  • Update the Input.IncludeDirectories setting to point to third party and system includes can be found.
  • Update the Input.RootDirectory to point to the base directory of the source code.
  • Update the Output.Filename to the name of the product.
  • Update LogLevel if required.
• Run the analyzer from the command line with the analyzer settings filename as argument.
• The analyzer will:
  • Parse C/C++ source files and determines dependencies based on header file includes.
  • The found elements and dependencies are written to the OutputFilename.
  • At the end of the analysis the percentage of the relations that could be resolved is shown. This is an indication of the reliability of the dependency model.
• If the percentage lower than 100% look at the log files to find out the reason.
• Import the DSI file in the DSM viewer.

Command line usage

Use the following command to run a analysis:

"C:\Program Files\DsmSuite\Analyzers\C++\DsmSuite.Analyzer.Cpp.Exe" AnalyzerSettings.xml

Settings

The following settings are defined:

AnalyzerSettings.xml example

Example for analyzing C++ in a D:\MyProject source directory.

<?xml version="1.0" encoding="utf-8"?>
<AnalyzerSettings xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <LogLevel>Error</LogLevel>
  <Input>
    <RootDirectory>C:\</RootDirectory>
    <SourceDirectories>
      <string>C:\</string>
    </SourceDirectories>
    <ExternalIncludeDirectories>
      <string>C:\</string>
    </ExternalIncludeDirectories>
    <IgnorePaths>
      <string>C:\</string>
    </IgnorePaths>
  </Input>
  <Analysis>
    <ResolveMethod>AddBestMatch</ResolveMethod>
  </Analysis>
  <Transformation>
    <IgnoredNames />
    <AddTransitiveIncludes>false</AddTransitiveIncludes>
    <HeaderSourceFileMergeStrategy>None</HeaderSourceFileMergeStrategy>
    <MergeHeaderAndSourceFileDirectoryRules>
      <TransformationMergeRule>
        <From>inc.</From>
        <To>src.</To>
      </TransformationMergeRule>
    </MergeHeaderAndSourceFileDirectoryRules>
  </Transformation>
  <Output>
    <Filename>Output.dsi</Filename>
    <Compress>true</Compress>
  </Output>
</AnalyzerSettings>

Additional Logging

The following additional logging files defined.

When logging is enabled the following types of logging are provided of the analysis:

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