Gcov For Mac

The GNAT Studio is a powerful and intuitive IDE that supports the full development workflow, from coding to system integration, testing, debugging, and code analysis. GNAT Studio is versatile and customizable and gives you easy access to the GNAT Pro technologies.

A Lightweight, Powerful IDE

GNAT Studio is a multi-language IDE with advanced support out-of-the-box for Ada, SPARK, C, C++ and Python. With GNAT Studio you get advanced code intelligence and navigation features and the ability to produce graphs of project organization, source dependencies and type / class inheritance.

GNAT Studio gives you a direct interface to the GNAT Pro tools and thus easy access to program builders, debuggers, and static and dynamic analysis tools. It also allows integration of third-party version control systems and can be tailored to your specific project needs.

Versatile and Extensible

Especially suited for large, complex systems, GNAT Studio is designed with versatility in mind, and can adapt to systems of any complexity.

From Mac OS X 10.9 onward, if Xcode is already installed in Mac OS X then Command Line Tools becomes installed as well (you can check this by trying to run gcc or make from the terminal). Accordingly, this tutorial is aimed at users who do not want to install the broader Xcode development package, and would rather only have the command line.

The IDE is highly extensible. A straightforward scripting approach lets you tailor GNAT Studio to meet your workflow requirements and to integrate additional tools. With its built-in support for remote programming, GNAT Studio can run on a local workstation while the build and debug processes are performed on a separate server.

Its appearance and behavior can also be tailored to accommodate various project-specific preferences.

  1. App description: Graphical front-end for GCC’s coverage testing tool (gcov). Mac, iMac, Macbook, OSX, Yosemite, Mavericks, Mountain Lion, Lion, Snow Leopard.
  2. Code coverage tool gcov free download. OpenCover OpenCover is a free and open source code coverage tool for.NET 2 and above (Windows OSs only - no M.

This article has been migrated from my original post at embeddedinn.wordpress.com.

Any large code base needs to be incrementally tested for each release for regressions and bugs. When the code base grows, manual testing fails to meet the requirements and we have to move into automated systems for testing. Once a test is written, we have excellent continuous integration systems like Jenkins or Cruise Control to validate the tests against any changes made on the code. However, the CI system is only as effective as the test. If the test does not cover all use cases, then there is no point in running the tests in CI.

Gcov for macbook

This article intends to illustrate the use of ‘gcov’ to estimate the dynamic coverage of a test. The article speaks solely from the viewpoint of a C programmer working on a Linux PC (or similar systems)

What is coverage?

All large scale, usable C code is written in the form of blocks of code enclosed in functions. A block can be a set of simple execution statements or a logical branch.

The ideal test code should logically call all the functions and execute all statements in the blocks. The percentage of lines of actual code that gets executed when a test code runs is called the coverage of the test code. More the number of lines of code that is tested, less is the probability to get a last minute surprise bug.

There are two types of coverage analysis that is possible.

Static code coverage analysis is done by analyzing the test code and the actual code to primarily estimate the function call coverage. Static code coverage analysis is much faster and simpler since the generated object file need not be executed. This is particularly handy in the case of small scale embedded systems.

Dynamic code coverage analysis is much more elaborate and requires the test code to be executed on the target. It also requires the object file to be generated with special compilation options. However, it gives much more detailed analysis of how effective the test is.

For obvious reasons, it is not practical to manually compute the coverage of a test code. Thus we have some tools that can compute the coverage of our test code for us. We will now look into the details of how ‘gcov’ can be used for dynamic code coverage analysis.

GCOV

As per Wikipedia, Gcov is a source code coverage analysis and statement-by-statement profiling tool. Gcov generates exact counts of the number of times each statement in a program is executed and annotates source code to add instrumentation. Gcov comes as a standard utility with GNU CC Suite (GCC)

Gcov provides the following details:

  • How often each line of code executes
  • What lines of code are actually executed
  • How much computing time each section of code uses

Getting Started With GCOV

When using gcov, you must first compile your program with –coverage GCC option.

This tells the compiler to generate additional information needed by gcov (basically a flow graph of the program) and also includes additional code in the object files for generating the extra profiling information needed by gcov. These additional files (.gcno) are placed in the directory where the object file is located.

Once the object file is generated, execute it once to get the profile file (.gcda)

Once we have the gcna and gcda files , we can now run gcov.

To illustrate the usage of gcov, we will consider a very minimal library (lib.c) and it test suite (test.c) .

lib.c

test.c

Compilation command for the test code :

gcc --coverage lib.c test.c –o test

Gcov For C++

This will generate the following files:

  • lib.gcno – library flow graph
  • test.gcno – test code flow graph
  • test – test code executable

Now, execute the test code object file. This will generate the following files

  • lib.gcda – library profile output
  • test.gcda – test code profile output

Now we have all the inputs required for gcov to generate the coverage report. To generate the coverage report, run the following command

gcov -abcfu lib.c

Coverage summary will be displayed as below when gcov finishes execution:

Detailed coverage report will be available in the lib.c.gcov file generated by gcov

Each block is marked by a line with the same line number as the last line of the block and the number of branch and calls in the block.

Each function is preceded with a line showing the number of times the function is called, number of times it returns and the percentage of function blocks that were executed.

Each line of executable code contains the number of times the line was executed and the actual source code line number. Any line that was not executed will have ##### in place of the execution count. Blocks that are not executed will have $$$$$ in place of the execution count.

The command line option summary for gcov is given below:

-h, –helpPrint this help, then exit
-v, –versionPrint version number, then exit
-a, –all-blocksShow information for every basic block
-b, –branch-probabilitiesInclude branch probabilities in output
-c, –branch-countsGiven counts of branches taken rather than percentages
-n, –no-outputDo not create an output file
-l, –long-file-namesUse long output file names for included source files
-f, –function-summariesOutput summaries for each function
-o, –object-directoryDIRFILE Search for object files in DIR or called FILE
-p, –preserve-pathsPreserve all pathname components
-u, –unconditional-branchesShow unconditional branch counts

Visualizing results with LCOV

The Linux testing project (LTP) has come up with a tool called lcov that provides a more user-friendly graphical visualization of the gcov output. It generates html files and integrates well with web based CI systems.

To make lcov generate html reports for you, give the following commands once the gcno and gcda files are generated.

lcov --directory . –zerocounters
lcov --directory . --capture --output-file app.info
genhtml app.info

The lcov reports seen from a browser is shown in the screenshots below.

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Cross Profiling

This section is adapted from the GCOV manual :

As we have seen so far, running the program to be profiled will cause profile output to be generated. For each source file compiled with the –coverage option, a .gcda file will be generated in the object file directory. This places a restriction that the target system should have the same directory structure. (The program will try to create the needed directory structure, if it is not already present).

As per the gnu GCOV documentation, redirection can be done with the help of two execution environment variables.

  • GCOV_PREFIX : Contains the prefix to add to the absolute paths in the object file. Prefix can be absolute, or relative. The default is no prefix.
  • GCOV_PREFIX_STRIP : Indicates the how many initial directory names to strip off the hardwired absolute paths. Default value is 0.

Gcov Macos

Note: If GCOV_PREFIX_STRIP is set without GCOV_PREFIX is undefined, then a relative path is made out of the hardwired absolute paths.

For example, if the object file /user/build/foo.o was built with -fprofile-arcs, the final executable will try to create the data file /user/build/foo.gcda when running on the target system. This will fail if the corresponding directory does not exist and it is unable to create it. This can be overcome by, for example, setting the environment as GCOV_PREFIX=/target/run and GCOV_PREFIX_STRIP=1. Such a setting will name the data file /target/run/build/foo.gcda.

Gcov Macros

You must move the data files to the expected directory tree in order to use them for profile directed optimizations (–use-profile), or to use the gcov tool.