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Caution: This version of this document is no longer maintained. For the latest documentation, see http://www.qnx.com/developers/docs.

Using Code Coverage

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Utilities Used by the IDE Getting System Information Using Code Coverage Common Wizards Reference Preparing Your Target Developing Photon Applications Developing C/C++ Programs Where Files Are Stored Building OS and Flash Images Migrating to the 6.3 Release Tutorials IDE Concepts About This Guide Analyzing Your System With Kernel Tracing Profiling an Application Finding Memory Errors Debugging Programs Managing Source Code Launch Configurations Reference

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Use the Code Coverage tool to help test your code.

In this chapter...

Code coverage in the IDE

Code coverage is a way to measure how much code a particular process has executed during a test or benchmark. Using code-coverage analysis, you can then create additional test cases to increase coverage and determine a quantitative measure of code coverage, which is an indirect measure of the quality of your software (or better, a direct measure of the quality of your tests).

Types of code coverage

Several types of metrics are commonly used in commercial code-coverage tools, ranging from simple line or block coverage (i.e. "this statement was executed") to condition-decision coverage (i.e. "all terms in this Boolean expression are exercised"). A given tool usually provides a combination of types.

The coverage tool in the IDE is a visual font end to the gcov metrics produced by the gcc compiler. These coverage metrics are essentially basic block coverage and branch coverage.

The IDE presents these metrics as line coverage, showing which lines are fully covered, partially covered, and not covered at all. The IDE also presents percentages of coverage in terms of the actual code covered (i.e. not just lines).

Block coverage

Block coverage, sometimes known as line coverage, describes whether a block of code, defined as not having any branch point within (i.e. the path of execution will enter from the beginning and exit at the end.) is executed or not.

By tracking the number of times the block of code has been executed, the IDE can determine the total coverage of a particular file or function. The tool also uses this information to show line coverage by analyzing the blocks on each line and determining the level of coverage of each.

Branch coverage

Branch coverage can track the path of execution taken between blocks of code. Although this metric is produced by the gcc compiler, currently the IDE doesn't provide this information.

How the coverage tool works

The IDE's code coverage tool works in conjunction with the compiler (gcc), the QNX C library (libc), and optionally the remote target agent (qconn). When code coverage is enabled for an application, the compiler will instrument the code so that at run time, each branch execution to a basic block is counted. During the build, the IDE produces data files in order to recreate the program's flow graph and to provide line locations of each block.

Caution: Since the IDE creates secondary data files at compilation time, you must be careful when building your programs in a multi-targeted build environment such as QNX Neutrino.

You must either:

  • ensure that the last compiled binary is the one you're collecting coverage data on,


  • simply enable only one architecture and debug/release variant.

Note also that the compiler's optimizations could produce unexpected results, so you should perform coverage tests on a non-optimized, debug-enabled build.

When you build a program with the Build with Code Coverage build option enabled and then launch it using a C/C++ QNX Qconn (IP) launch configuration, the instrumented code linked into the process will connect to qconn, allowing the coverage data to be read from the process's data space.

But if you launch a coverage-built process with coverage disabled in the launch configuration, this will cause the process to write the coverage information to a data file (.da) at run time, rather than read it from the process's data space.

Note: You should use data files only if you're running the local launch configuration on a QNX Neutrino self-hosted development system. Note that the data can later be imported into the IDE code coverage tool.

Once a coverage session has begun, you can immediately view the data. The QNX Code Coverage perspective contains a Code Coverage Sessions view that lists previous as well as currently active sessions. You can explore each session and browse the corresponding source files that have received coverage data.

Enabling code coverage

To build executables with code coverage enabled:

  1. In the C/C++ Projects view, right-click your project and select Properties. The properties dialog for your project appears.
  2. In the left pane, select QNX C/C++ Project.
  3. In the Build Options pane, check Build with Code Coverage.
  4. In the Build Variants tab, check only one build variant.
    Note: If the IDE is set to build more than one variant, an error is displayed and the OK button is disabled.

  5. Click OK.
  6. In the C/C++ Projects view, right-click your project and select Rebuild Project.

Enabling code coverage for Standard Make projects

If you're using your own custom build environment, rather than QNX makefiles, you'll have to manually pass the coverage option to the compiler.

To enable code coverage for non-QNX projects

  1. Compile using these options to gcc:
    -fprofile-arcs -ftest-coverage

    If your using qcc, compile with:

    -Wc,-fprofile-arcs -Wc,-ftest-coverage
  2. Link using the -p option.

For example, your makefile might look something like this:

objects:=Profile.o main.o

CC:=qcc -Vgcc_ntox86
CFLAGS:=-g -Wc,-ftest-coverage -Wc,-fprofile-arcs -I. -I../proflibCPP-std
LDFLAGS:=-p -g -L../proflibCPP-std -lProfLib -lcpp

all: profileCPP-std

    -rm $(objects) profileCPP-std *.bb *.bbg

profileCPP-std: $(objects)
    $(CC) $^ -o $@ $(LDFLAGS)

Starting a coverage-enabled program

To start a program and measure the code coverage:

  1. Create a C/C++ QNX QConn (IP) launch configuration as you normally would, but don't click OK yet.
  2. On the launcher, click the Tools tab.
  3. Click Add/Delete Tool. The Tools selection dialog appears.
  4. Check the Code Coverage tool:

    Launcher; Tools tab; Code Coverage tool

  5. Click OK.
  6. Click the Code Coverage tab, and fill in these fields:

    Launcher; Tools tab; Code Coverage tool

    Enable GCC 3 Coverage metrics collection
    Check this if your application was compiled with gcc 3.3.1 or later. The default is to collect code coverage information from applications compiled with gcc 2.95.3.
    Code Coverage data scan interval (sec)
    This option sets how often the Code Coverage tool polls for data. A low setting can cause continuous network traffic. The default setting of 5 s should suffice.
    Referenced projects to include coverage data from
    Check any project in this list you wish to gather code-coverage data for. Projects must be built with coverage enabled.
    Comments for this coverage session
    Your notes about the session, for your own personal use. The comments appear at the top of the generated reports.
  7. Check Switch to this tool's perspective on launch if you want to automatically go to the QNX Code Coverage perspective when you run or debug.
  8. Click Apply.
  9. Click Run or Debug.

Controlling your session

The Code Coverage Sessions view lets you control and display multiple code-coverage sessions:

Code Coverage Sessions view

The view displays the following as a hierarchical tree for each session:

Session item Description Possible icons
Code coverage session Launch configuration name, coverage tool, and start time (e.g. ccov102_factor [GCC Code Coverage] (7/2/03 2:48 PM)) Icon: Inactive session Icon: Remove analysis
Project Project name and amount of coverage (e.g. ccov102_factor [ 86.67% ]) Icon: Project
File Filename and amount of coverage (e.g. ccov102_factor.c [ 86.67% ]) Icon: C file
Function Function name and amount of coverage (e.g. main [ 100% ]) Icon: Function

The IDE uses several icons in this view:

Icon Meaning
Icon: Has no coverage No coverage
Icon: Has some coverage Partial coverage
Icon: Has 100% coverage Full (100%) coverage
Icon: Out-of-Sync file Missing or out-of-date source file

The IDE also adds a coverage markup icon (Icon: Has coverage marker) to indicate source markup in the editor. (See the "Examining data line-by-line" section, below.)

To reduce the size of the hierarchical tree, click the Collapse All (Icon: Collapse All) button.

To combine several sessions:

  1. In the Code Coverage Sessions view, select the sessions you want to combine.
  2. Right-click your selections and select Combine/Copy Sessions. The IDE prompts you for a session name and creates a combined session.

Examining data line-by-line

The IDE can display the line-by-line coverage information for your source code. In the left margin, the editor displays a "covered" icon (Icon: Executed line marker) beside each line of source. In the right margin, the editor displays a summary of the coverage by showing green sections for fully-covered code, yellow for partial coverage, and red for no coverage:

Editor; C/C++, showing code coverage

To open a file in the QNX Code Coverage perspective:

=>> In the Code Coverage Sessions view, expand a session and double-click a file or function.

To display coverage information from a particular session:

=>> In the Code Coverage Sessions view, right-click a session and select Coverage Markup, then select one of the following:
  • Mark lines not covered
  • Mark lines partially covered
  • Mark lines fully covered

The selected icon appears beside the corresponding source in the C/C++ editor. In the Code Coverage Sessions view, a coverage marker (Icon: Has coverage marker) overlays the source file icon.

To automatically show coverage information when opening a file:

  1. Open the Preferences dialog (Window-->Preferences).
  2. In the left pane, select QNX-->Code Coverage.
  3. In the right pane, check the desired markers in the Coverage markup when file is opened field.
  4. Click OK. The next time you open a file, the markers appear automatically. To add markers from another session, add them manually, as described above.

To remove all coverage markers:

=>> In the Code Coverage Sessions view's title bar, click the Remove All Coverage Markers button (Icon: Remove All Coverage Markers).

Examining your coverage report

The Code Coverage Report view provides a summary (in XML) of your session. The view lets you drill down into your project and see the coverage for individual files and functions:

Code Coverage Report view

To generate a report, simply right-click a coverage session and select Generate Report.

By default, the IDE displays reports in the Code Coverage Report view, but you can also have the IDE display reports in an external browser. Using an external browser lets you compare several reports simultaneously.

To toggle between viewing reports in the Code Coverage Report view and in an external browser:

  1. Open the Preferences dialog (Window-->Preferences).
  2. In the left pane, select QNX-->Code Coverage.
  3. In the right pane, check/uncheck the View reports in external browser item.
  4. Click OK.

To print a report:

=>> In the Code Coverage Report view's title bar, click the Print button (Icon: Print).

To save a report:

  1. Right-click in the Report view to display the context menu.
  2. Click Save As... to save the report.

You can also refresh the report:

=>> In the Code Coverage Report view's title bar, click the Refresh button (Icon: Refresh).

Seeing your coverage at a glance

The Properties view displays a summary of the code coverage for a project, file, or function you've selected in the Code Coverage Sessions view.

The Properties view tells you how many lines were covered, not covered, and so on:

Properties view; Code coverage

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