CDT/designs/StaticAnalysis

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Project Goal

Code Name: "Codan" - stands for CODe ANalysis

The Goal is to create a light-weight static analysis framework in CDT that allows to easily plug in "checkers" which would perform real analysis on the code to find common defects, violation of policies, etc.

Intended users of the "Codan" framework:

  • Tool Vendors
    • To create plugins containing end-user checkers and templates
  • Software Architects, Process Enforcement
    • To create customized new checkers, based on templates (no programming involved)
    • To create problem profiles
  • Developer, Tester, Code Inspector
    • To check for errors as you type and have a quick way to fix them, during development
    • To find bugs, security violations, API violations, coding standard violations during code inspection and before code execution


Framework contains common components and APIs that are shared between static analysis tools for C/C++, such as:

  • User Interface to control the Problems enablement and parameters
  • Different launch modes (as you type, on demand, as a builder)
  • An eclipse View to display additional problem information (such as extra backtrace or more complex problem parameters)
  • A Generic Marker type for problems with extra fields
  • API to run log the problems
  • Base classes for checkers
  • JUnit testing framework
  • Checker examples


Requirements for Google Summer of Code Students

User Experience

Code Analysis can be invoked in one of the following ways:

  • Select a "Run Code Analysis" command from Navigator context menu (file, directory, project or combination)

Codan RunCodan.png

  • Enable "Run on Build" in Project preferences "C/C++ Code Analysis->Build", in this case it would be run with Incremental and Full Build

Codan RunOnBuild.png

  • As you type (in the editor)


User can control Severity and Enablement of Problems on Workspace level or on Project level.

Codan ProjectProperties.png

If Problems are found, they would be displayed in the Problems view. Each problem would have a specific type, which can be grouped by or filtered out by the view controls.

Codan ProblemsView.png

Examples of possible Problems

  • Assignment in condition
 if (a=b) { ... }
  • Statement has not effect
 a+b;
  • Function name does not meet policy rules (should start with a lowercase letter)
 void My_function() {}


Please edit this page for problem ideas: Ideas

Create a Checker

To create a simple checker you would have to extend one of the framework classes, and add extension points where you specify a class name and describe a problem, such as name, default severity, etc. Name would be visible on the Configuration page.

To create a checker:

  1. Define a problem(s) that your checker is capable of finding, cross check existing checkers to see if it is already there, create a bug report describing your intention to implement it
  2. Start coding:
    • check out all plugins from dev.eclipse.org:/cvsroot/tools/org.eclipse.cdt/codan (use cdt checkout instructions) as separate eclipse projects
    • create a plugin for your checkers or use org.eclipse.cdt.codan.checkers
    • create an extension point for org.eclipse.cdt.codan.core.checkers. Specify one or more problem that your checker can detect with name, id, default severity and enablement
    • note: severity of the problem is user defined. If you are creating a frontend for a command line static analysis tool (such as lint) which can have different severity for same error, you have to create an id per severity per problem type. For example for "Null pointer dereference" you create npd.error and npd.warning ids. Users may define both of them as warnings for IDE.
    • create a class in selected plugin which implements IChecker interface. You can pick default abstract implementation such as AbstractIndexAstChecker, see examples in org.eclipse.cdt.codan.checkers.sample
    • create a tests for your checker, it is pretty easy to do with existing framework see StatementHasNoEffectCheckerTest class as an example
  3. Create a patch and attach it to your bug

Extension Point

This is example of extension point:

  <extension
        point="org.eclipse.cdt.codan.core.checkers">
     <checker
           class="org.eclipse.cdt.codan.checkers.sample.AssignmentInConditionChecker"
           id="org.eclipse.cdt.codan.checkers.checker1"
           name="Assignment in condition">
        <problem
           defaultSeverity="Warning"
           id="org.eclipse.cdt.codan.checkers.sample.assignment_in_condition"
           name="Assignment in condition">
        </problem>
     </checker>
  </extension>

API

API would contain:

  • Interfaces such as IProblem, IProblemCategory, IChecker, etc
  • Interface to call Problem Logging - provides means to report a problem (which would become a marker)
  • Interface to query status of problem enablement (for optimization purposes)
  • Abstract classes for Checkers (such as AbstractIndexAstChecker). For example class for C AST Visitor, which would use CDT C/C++ AST to find errors. Checkers can also use other models and even just plain text files (to find swear words or something...)
  • Programmatic access to a launch the analysis
  • Problem profile change listener - this allows for example to save problems enablement to a file to use in external make integrations

Non API Framework Parts:

  • Builder - framework would register a project builder for "Code Analysis". This builder can be used by all checkers and can be turn on/off by user, which allows to perform checks while building (or not)
  • Run On demand - provides a command to run "Code Analysis" on demand on selected files or set of resources
  • Problem configuration - provides workspace level and project level problem configuration that allows to turn problems on and off, and change severity between standard problem severity
  • Marker Type - provide a market type for simple problems. Sophisticated checkers can use their own marker types.
  • Common Categories - set of common Categories for problems, such as Java has, for example "Programming Errors", "Unused Code and Objects", "Security Violations"...
  • Checkers extension point - allows to contribute a checker by using extension point, which means different problems can be contributed by different plugins with potentially different vendors, but would have same user interface and look and feel.


Current code resides in dev.eclipse.org:/cvsroot/tools/org.eclipse.cdt/codan

Deployment

Currently, this framework is packaged with CDT version 7.0. Also can work with 6.0, to include it in your CDT 6.0 based tool you need to manually export plugins located in dev.eclipse.org:/cvsroot/tools/org.eclipse.cdt/codan (can be done using export wizard) and add them to your distribution.

Framework only

  • org.eclipse.cdt.codan-feature
  • org.eclipse.cdt.codan.core
  • org.eclipse.cdt.codan.core.cxx
  • org.eclipse.cdt.codan.ui
  • org.eclipse.cdt.codan.ui.cxx

Checkers

  • org.eclipse.cdt.codan.checkers
  • org.eclipse.cdt.codan.checkers.ui

Testing & Examples

  • org.eclipse.cdt.codan.core.test
  • org.eclipse.cdt.codan.examples
  • org.eclipse.cdt.codan.ui.cfgview

Future work

  • User defined checker's preferences, for example if it checks for policy violations on function name let user specify name pattern using UI
    • partially done
  • Build shared models other than AST with bindings, such as Control Graph, Data Flow Graph (this was done in ptp project, maybe just bring it over)
    • control graph is done for C (no exception support for c++)
  • Some common code to support Quick Fix for the problems
    • there is some common code now
  • Common scope filters for checkers (excluded/included files)
  • Other static analysis application can become part of the project, such as: searchers, metrics, software models, etc

Source & Bugs

Source located at

dev.eclipse.org:/cvsroot/tools/org.eclipse.cdt/codan

API for C/C++ AST:

http://help.eclipse.org/galileo/index.jsp?topic=/org.eclipse.cdt.doc.isv/reference/api/overview-summary.html

Send questions to cdt-dev list:

https://dev.eclipse.org/mailman/listinfo/cdt-dev

Send bugs to

  • Project: Tools->CDT
  • Component: cdt-codan
  • Prefix: [fp] for false positive, [fn] for false negative
  • List of current bugs