QA:CodeCoverage

In order to perform code coverage exercise on the Firefox browser, we need to go through at least two iterations.

First : Instrument the C/C++ code in the Firefox browser using 'gcov' and run all tests against the browser.

Second: Instrument the javascript part of the Firefox browser and run all tests against the browser.

Finally we will generate a combined report which would also have the path traversal capability so that we can look at the details of coverage at the source code line level.

• STEP 1

      Create a .mozconfig file with the following statements

       export CFLAGS="-fprofile-arcs -ftest-coverage"
       export CXXFLAGS="-fprofile-arcs -ftest-coverage"
       export EXTRA_DSO_LDFLAGS="-lgcov -static-libgcc"
       export LDFLAGS="-lgcov -static-libgcc"
       ac_add_options --enable-application=browser
       mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../mozcentral-dbg
       ac_add_options --enable-tests
       ac_add_options --enable-mochitest
       ac_add_options --enable-debug
       ac_add_options --disable-optimize
       ac_add_options --enable-jsd
       mk_add_options MOZ_MAKE_FLAGS="-j3"
       mk_add_options AUTOCONF=autoconf2.13

As of now, there is a bug https://bugzilla.mozilla.org/show_bug.cgi?id=461270 which prevents the NSPR from getting linked in the code coverage mode.

The work around to address this problem is as follows:

• Modify [ in the trunk you checked out ] src/nsprpub/config/rules.mk on line #352
  • Change it from $(MKSHLIB) $(OBJS) $(RES) $(EXTRA_LIBS) to $(MKSHLIB) $(OBJS) $(RES) $(EXTRA_LIBS) $(LD_FLAGS)

Execute the usual build command 'make -f client.mk build'

Please make sure that you have all the build dependencies installed properly before attempting the build.

Once the build is ready , all you have to do is to go into

~/mozcentral-dbg/_tests/testing/mochitest and execute the following command.

• python runtests.py

Please keep the focus on the Firefox browser at all times or else your tests will fail.

After you are done with the test runs, you will end up with a bunch of *.gcda and *.gcno files in your build directory.

Now, come back into your home directory and execute the following command

       lcov -c -i -d mozcentral-dbg -o app.info

The lcov tool will go through the entire build directory and generates an app.info file in your home directory

Then, execute the following command

        genhtml app.info
        If by any chance the above command fails to complete, use the following option.
        genhtml --no-source app.info

The resulting index.html is the landing page for all your code coverage data for the C/C++ code in the Firefox browser.