Building an application with clang with --coverage on windows - windows

Question

i'm trying to build a simple cmake application to test the coverage functionality offer by clang in windows (in linux all work ok).
Environment is:
Clang version in use: 7.0
And using LLVM toolset with Visual Studio 2017 build tools
cmake 3.12 with ninja generator
What I'm doing is simple:
CMakeLists.txt
cmake_minimum_required(VERSION 3.0.2 FATAL_ERROR)
project(test)
add_compile_options(--coverage)
add_executable(${PROJECT_NAME}
main.cpp
)
the main.cpp is as simple as it can get:
#include <iostream>
#include <string>
int main(int argc, char const *argv[]) {
std::cout << "\ndone.\n";
return 0;
}
using the build tools environments vcvarsall.bat i initialize the environement to run and compile with clang, like that:
mkdir build
cd build
cmake -GNinja -DCMAKE_C_COMPILER=clang-cl -DCMAKE_CXX_COMPILER=clang-cl -DCMAKE_LINKER=lld-link ..
cmake --build .
and the following errors hapear:
lld-link.exe: error: undefined symbol: __llvm_profile_runtime
>>> referenced by src\app\CMakeFiles\app.dir\main.cpp.obj:(__llvm_profile_runtime_user)
lld-link.exe: error: undefined symbol: __llvm_profile_register_function
>>> referenced by src\app\CMakeFiles\app.dir\main.cpp.obj:(__llvm_profile_register_functions)
>>> referenced by src\app\CMakeFiles\app.dir\main.cpp.obj:(__llvm_profile_register_functions)
What i'm doing wrong or what i need to link to?
Thanks
Update: with Fred input I realized what library I should be linking to, and if I add the following:
link_libraries("C:/Program Files/LLVM/lib/clang/7.0.0/lib/windows/clang_rt.profile-x86_64.lib")
everything works... but is this really the solution for my problem?

Answer 1

According to these Notes and Notes and simple example and another example you need to do this differently.
target_compile_options(${PROJECT_NAME} PRIVATE -fprofile-instr-generate -fcoverage-mapping)
target_link_libraries(${PROJECT_NAME} PRIVATE -fprofile-instr-generate -fcoverage-mapping)
I haven't tested the syntax or anything.
From what I gather is that --coverage is an older flag of making gcov compatible data. The LLVM documents give an example of -fprofile-instr-generate -fcoverage-mapping at compile and link command there is no documentation of --coverage. One of the examples say you need to link with --coverage the other example says you need to link with -fprofile-instr-generate -fcoverage-mapping and it will link in the profile libraries as needed.