Use LLVM_COV and LLVM_PROFDATA variables over COVERAGE_GCOV_PATH

They are provided by the C++ rules and make it clearer what tool is
what. Also changes the C++ LLVM coverage test to specify GCOV as
llvm-cov, since that is the analogous tool and better represents how a
LLVM based tool chain might be configured.

src/test/shell/bazel/bazel_coverage_cc_test_llvm.sh

@@ -60,7 +60,7 @@ function setup_llvm_coverage_tools_for_lcov() {
   add_to_bazelrc "common --repo_env=BAZEL_LLVM_PROFDATA=${llvm_profdata}"
   add_to_bazelrc "common --repo_env=BAZEL_USE_LLVM_NATIVE_COVERAGE=1"
   add_to_bazelrc "common --repo_env=CC=${clang}"
-  add_to_bazelrc "common --repo_env=GCOV=${llvm_profdata}"
+  add_to_bazelrc "common --repo_env=GCOV=${llvm_cov}"
   add_to_bazelrc "common --experimental_generate_llvm_lcov"
 }
 

src/test/shell/bazel/coverage_helpers.sh

@@ -31,16 +31,14 @@ function get_gcov_version() {
   #   gcov (Debian 7.3.0-5) 7.3.0
   # llvm-cov gcov --version outputs a line like:
   #   LLVM version 9.0.1
-  local version=$("${gcov_location}" --version | sed -n -E -e 's/^.*\s([0-9]+)\.[0-9]+\.[0-9]+\s?.*$/\1/p')
+  # gcov (actually llvm-cov) on OS X outputs:
+  #   Apple LLVM version 12.0.5
+  local version=$("${gcov_location}" --version | sed -n -E -e 's/^.* ([0-9]+)\.[0-9]+\.[0-9]+ ?.*$/\1/p')
   if [ "$version" -lt 7 ]; then
       echo "gcov versions before 7.0 is not supported."
       return 1
   fi
 
-  # Disable llvm-cov for now - coverage tests on OSX don't work
-  # TODO(cmita): Fix and enable.
-  "$gcov_location" -version | grep "LLVM" && \
-      echo "gcov LLVM version not supported." && return 1
   echo "$version"
 }
 

tools/test/collect_cc_coverage.sh

@@ -32,6 +32,8 @@
 # - ROOT                    Location from where the code coverage collection
 #                           was invoked.
 # - VERBOSE_COVERAGE        Print debug info from the coverage scripts
+# - LLVM_COV                Location of llvm-cov
+# - LLVM_PROFDATA           Location of llvm-profdata
 #
 # The script looks in $COVERAGE_DIR for the C++ metadata coverage files (either
 # gcda or profraw) and uses either lcov or gcov to get the coverage data.
@@ -78,7 +80,7 @@ function init_gcov() {
 function llvm_coverage_lcov() {
   local output_file="${1}"; shift
   export LLVM_PROFILE_FILE="${COVERAGE_DIR}/%h-%p-%m.profraw"
-  "${COVERAGE_GCOV_PATH}" merge -output "${output_file}.data" \
+  "${LLVM_PROFDATA}" merge -output "${output_file}.data" \
       "${COVERAGE_DIR}"/*.profraw
 
   local object_param=""
@@ -98,7 +100,7 @@ function llvm_coverage_lcov() {
 function llvm_coverage_profdata() {
   local output_file="${1}"; shift
   export LLVM_PROFILE_FILE="${COVERAGE_DIR}/%h-%p-%m.profraw"
-  "${COVERAGE_GCOV_PATH}" merge -output "${output_file}" \
+  "${LLVM_PROFDATA}" merge -output "${output_file}" \
       "${COVERAGE_DIR}"/*.profraw
 }
 
@@ -140,7 +142,9 @@ function gcov_coverage() {
           #   gcov (Debian 7.3.0-5) 7.3.0
           # llvm-cov gcov --version outputs a line like:
           #   LLVM version 9.0.1
-          gcov_major_version=$("${GCOV}" --version | sed -n -E -e 's/^.*\s([0-9]+)\.[0-9]+\.[0-9]+\s?.*$/\1/p')
+          # gcov (actually llvm-cov) on OS X outputs:
+          #   Apple LLVM version 12.0.5
+          gcov_major_version=$("${GCOV}" --version | sed -n -E -e 's/^.* ([0-9]+)\.[0-9]+\.[0-9]+ ?.*$/\1/p')
 
           # Invoke gcov to generate a code coverage report with the flags:
           # -i              Output gcov file in an intermediate text format.