c++ coverage setup with CMake - c++

Question

I have CMake project that sometimes may use clang, sometimes it may use gcc, sometimes it may use MSVC.
Does CMake provide some generic way to enable coverage generation, or do I need to do if else by myself(compiler flags for gcc and clang differ, and MSVC does not have coverage)?

Answer 1

There is no central cmake option to handle such a situation, but some solutions could be:
Don't do anything. Collect coverage statistics with kcov, which doesn't require special compiler flags.
Add a build configuration alongside the usual Debug, RelWithDebugInfo and so on. Then, select this build configuration only when it makes sense, i.e., when compiling with clang or gcc. Like this:
set(CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}" CACHE STRING
"Build options: None Debug Release RelWithDebInfo MinSizeRel Coverage." FORCE)
# Use generator expression to enable flags for the Coverage profile
target_compile_options(yourExec
$<$<CONFIG:COVERAGE>:--coverage>)
# Don't forget that the linker needs a flag, too:
target_link_libraries(yourExec
PRIVATE $<$<CONFIG:COVERAGE>:--coverage>)
When you need to dispatch further on the compiler type, you can use generator expressions, too.
$<$<OR:$<CXX_COMPILER_ID:AppleClang>,
$<CXX_COMPILER_ID:Clang>,$<CXX_COMPILER_ID:GNU>>:-someOtherFlag>
but as far as I know, there are no real differences between clang and gcc with respect to coverage flags.
Don't add another build configuration, just define the above flags for the build configuration you intend to use for coverage reports, probably Debug. Then, it's obviously necessary to exclude MSVC.
target_compile_options(yourExec
$<$<AND:$<CONFIG:DEBUG>,$<NOT:CXX_COMPILER_ID:MSVC>>:--coverage>)
target_link_libraries(yourExec
PRIVATE $<$<AND:$<CONFIG:DEBUG>,$<NOT:CXX_COMPILER_ID:MSVC>>:--coverage>)