Code Coverage

llvm-cov gcov

Once you have generated the coverage data files, run llvm-cov gcov for each main source file where you want to examine the coverage results. This should be run from the same directory where you previously ran the compiler.

./configure \
  CFLAGS="--coverage" \
  LDFLAGS="--coverage"
make
cd src
gcov *.c

profile-instr

To use llvm-cov show, you need a program that is compiled with instrumentation to emit profile and coverage data. To build such a program with clang use the -fprofile-instr-generate and -fcoverage-mapping flags. If linking with the clang driver, pass -fprofile-instr-generate to the link stage to make sure the necessary runtime libraries are linked in.

./configure \
  CFLAGS="-fprofile-instr-generate -fcoverage-mapping" \
  LDFLAGS="-fprofile-instr-generate"
make
LLVM_PROFILE_FILE="$PWD/cov-%p.profraw" make test
llvm-profdata merge --sparse --output=cov.profdata cov-*.profraw