configuring code coverage with cmake

Question

I'm on a linux machine, trying to build a project using cmake that does out of source builds. For code coverage, I looked into gcov and followed a simple tutorial that generate appropriate files for a sample helloWorld.cpp program. The only requirement were to compile with -fprofile-arcs -ftest-coverage flags & link with -lgcov flag, which can be done altogether with -coverage flag.

Now here comes the tricky part. I have a CMakeLists.txt wit contents as shown below:

cmake_minimum_required (VERSION 2.8)
project (SomeName)

SET(GCC_COVERAGE_COMPILE_FLAGS "-g -O0 -coverage -fprofile-arcs -ftest-coverage")
SET(GCC_COVERAGE_LINK_FLAGS    "-coverage -lgcov")
SET( CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}" )
SET( CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} ${GCC_COVERAGE_LINK_FLAGS}" )

set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)

include_directories(include)
set(CATCH_HEADER_PATH ${PROJECT_SOURCE_DIR}/test/catch.hpp)

add_executable(runTest ${PROJECT_SOURCE_DIR}/test/test.cpp ${CATCH_HEADER_PATH}) 

So I've included appropriate compile time flags as well as linker flags too and appended them correctly. Another thing to note is set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin) line which says that executables will be generated inside bin directory.

Now everything works as intended except that coverage files aren't generated properly. I follow these steps :

mkdir build && cd build
cmake ..
make -j4
./bin/runTest

and no other file is generated inside bin folder. However on more inspection I found out that there is another location build/CMakeFiles/runTest.dir/test where test.cpp.o resides initially and after the final step ./bin/runTest, two new files - test.cpp.gcda & test.cpp.gcno are generated.

I've already tried copying test/test.cpp to build/CMakeFiles/runTest.dir/test and running gcov test.cpp but it fails stating - test.gcno:cannot open notes file

Answer 1

A mismatch in gcov and gcc version was making this happen. gcc symlink /usr/bin/gcc was set to newest gcc, same for g++ but gcov in $PATH was still pointing to older version of gcov.