Fix split post-processing of LLVM-based coverage (#18737)

`--experimental_split_coverage_postprocessing` now works in combination with `--experimental_generate_llvm_lcov`, which required adding the runtime objects as inputs to the separate coverage post-processing spawn. Previously, they were only added to the runfiles of the test action, which aren't (and shouldn't) be added to the coverage spawn.

As a side effect, this provides a more natural fix for #15121 than bb6f1a7, which added an additional check to only add those runtime objects to the `llvm-cov` command line that were present in runfiles. Now, since all runtime objects are staged as inputs, they are known to be available. This improves coverage accuracy when e.g. runtime objects are packaged into jars and loaded at runtime.

Along the way the common setup for LLVM-based coverage tests has been extracted into a helper function and the tests have been updated to work with a broader range of clang versions. Previously, tests weren't run at all due to the clang version on the runners not falling into the restrictive range. Now, the tests are executed on the Ubuntu 20.04 runner (but not on any other runners, including macOS).

Closes #18634.

PiperOrigin-RevId: 542055078
Change-Id: Id8851f8685bb7724891acca395bb91556ee2b29a

Co-authored-by: Fabian Meumertzheim <[email protected]>

Author: iancha1992

src/main/starlark/builtins_bzl/common/cc/cc_binary.bzl

@@ -184,7 +184,7 @@ def _add(ctx, linking_statically):
 def _get_file_content(objects):
     result = []
     for obj in objects:
-        result.append(obj.short_path)
+        result.append(obj.path)
         result.append("\n")
     return "".join(result)
 
@@ -195,7 +195,7 @@ def _add_transitive_info_providers(ctx, cc_toolchain, cpp_config, feature_config
         runtime_objects_list = ctx.actions.declare_file(ctx.label.name + "runtime_objects_list.txt")
         file_content = _get_file_content(runtime_objects_for_coverage)
         ctx.actions.write(output = runtime_objects_list, content = file_content, is_executable = False)
-        additional_meta_data = [runtime_objects_list]
+        additional_meta_data = [runtime_objects_list] + runtime_objects_for_coverage
 
     instrumented_files_provider = common.instrumented_files_info_from_compilation_context(
         files = instrumented_object_files,

src/test/shell/bazel/bazel_coverage_cc_test_llvm.sh

@@ -27,6 +27,41 @@ if [[ "${COVERAGE_GENERATOR_DIR}" != "released" ]]; then
   add_to_bazelrc "build --override_repository=remote_coverage_tools=${COVERAGE_GENERATOR_DIR}"
 fi
 
+# Configures Bazel to emit coverage using LLVM tools, returning a non-zero exit
+# code if the tools are not available.
+function setup_llvm_coverage_tools_for_lcov() {
+  local -r clang=$(which clang || true)
+  if [[ ! -x "${clang}" ]]; then
+    echo "clang not installed. Skipping test."
+    return 1
+  fi
+  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
+  if [ "$clang_version" -lt 9 ];  then
+    # No lcov produced with <9.0.
+    echo "clang versions <9.0 are not supported, got $clang_version. Skipping test."
+    return 1
+  fi
+
+  local -r llvm_profdata=$(which llvm-profdata || true)
+  if [[ ! -x "${llvm_profdata}" ]]; then
+    echo "llvm-profdata not installed. Skipping test."
+    return 1
+  fi
+
+  local -r llvm_cov=$(which llvm-cov || true)
+  if [[ ! -x "${llvm_cov}" ]]; then
+    echo "llvm-cov not installed. Skipping test."
+    return 1
+  fi
+
+  add_to_bazelrc "common --repo_env=BAZEL_LLVM_COV=${llvm_cov}"
+  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 --experimental_generate_llvm_lcov"
+}
+
 # Writes the C++ source files and a corresponding BUILD file for which to
 # collect code coverage. The sources are a.cc, a.h and t.cc.
 function setup_a_cc_lib_and_t_cc_test() {
@@ -109,31 +144,37 @@ function test_cc_test_llvm_coverage_doesnt_fail() {
 }
 
 function test_cc_test_llvm_coverage_produces_lcov_report() {
-  local -r clang="/usr/bin/clang"
-  if [[ ! -x ${clang} ]]; then
-    return
-  fi
-  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
-  if [ "$clang_version" -lt 9 ] || [ "$clang_version" -eq 10 ] || [ "$clang_version" -eq 11 ]; then
-    # No lcov produced with <9.0, no branch coverage with 10.0 and 11.0.
-    echo "clang versions <9.0 as well as 10.0 and 11.0 are not supported." && return
-  fi
+  setup_llvm_coverage_tools_for_lcov || return 0
+  setup_a_cc_lib_and_t_cc_test
 
-  local -r llvm_profdata="/usr/bin/llvm-profdata"
-  if [[ ! -x ${llvm_profdata} ]]; then
-    return
-  fi
+  bazel coverage --test_output=all //:t &>$TEST_log || fail "Coverage for //:t failed"
 
-  local -r llvm_cov="/usr/bin/llvm-cov"
-  if [[ ! -x ${llvm_cov} ]]; then
-    return
-  fi
+  local expected_result="SF:a.cc
+FN:3,_Z1ab
+FNDA:1,_Z1ab
+FNF:1
+FNH:1
+DA:3,1
+DA:4,1
+DA:5,1
+DA:6,1
+DA:7,0
+DA:8,0
+DA:9,1
+LH:5
+LF:7
+end_of_record"
 
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
+}
+
+function test_cc_test_llvm_coverage_produces_lcov_report_with_split_postprocessing() {
+  setup_llvm_coverage_tools_for_lcov || return 0
   setup_a_cc_lib_and_t_cc_test
 
-  BAZEL_USE_LLVM_NATIVE_COVERAGE=1 GCOV=$llvm_profdata CC=$clang \
-    BAZEL_LLVM_COV=$llvm_cov bazel coverage --experimental_generate_llvm_lcov \
-      --test_output=all //:t &>$TEST_log || fail "Coverage for //:t failed"
+  bazel coverage \
+    --experimental_split_coverage_postprocessing --experimental_fetch_all_coverage_outputs \
+      --test_env=VERBOSE_COVERAGE=1 --test_output=all //:t &>$TEST_log || fail "Coverage for //:t failed"
 
   local expected_result="SF:a.cc
 FN:3,_Z1ab
@@ -151,29 +192,11 @@ LH:5
 LF:7
 end_of_record"
 
-  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log))"
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
 }
 
 function test_cc_test_with_runtime_objects_not_in_runfiles() {
-  local -r clang="/usr/bin/clang"
-  if [[ ! -x ${clang} ]]; then
-    return
-  fi
-  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
-  if [ "$clang_version" -lt 9 ] || [ "$clang_version" -eq 10 ] || [ "$clang_version" -eq 11 ]; then
-    # No lcov produced with <9.0, no branch coverage with 10.0 and 11.0.
-    echo "clang versions <9.0 as well as 10.0 and 11.0 are not supported." && return
-  fi
-
-  local -r llvm_profdata="/usr/bin/llvm-profdata"
-  if [[ ! -x ${llvm_profdata} ]]; then
-    return
-  fi
-
-  local -r llvm_cov="/usr/bin/llvm-cov"
-  if [[ ! -x ${llvm_cov} ]]; then
-    return
-  fi
+  setup_llvm_coverage_tools_for_lcov || return 0
 
   cat << EOF > BUILD
 cc_test(
@@ -206,10 +229,8 @@ int main(int argc, char const *argv[])
 EOF
 
 
-  BAZEL_USE_LLVM_NATIVE_COVERAGE=1 GCOV=$llvm_profdata CC=$clang \
-    BAZEL_LLVM_COV=$llvm_cov bazel coverage --experimental_generate_llvm_lcov \
-      --test_output=all --instrument_test_targets \
-        //:main &>$TEST_log || fail "Coverage for //:main failed"
+  bazel coverage --test_output=all --instrument_test_targets \
+      //:main &>$TEST_log || fail "Coverage for //:main failed"
 
   local expected_result="SF:main.cpp
 FN:4,main
@@ -225,7 +246,7 @@ LH:5
 LF:5
 end_of_record"
 
-  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log))"
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
 }
 
 function setup_external_cc_target() {
@@ -306,42 +327,17 @@ EOF
 }
 
 function test_external_cc_target_can_collect_coverage() {
-  local -r clang="/usr/bin/clang"
-  if [[ ! -x ${clang} ]]; then
-    return
-  fi
-  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
-  if [ "$clang_version" -lt 9 ] || [ "$clang_version" -eq 10 ] || [ "$clang_version" -eq 11 ]; then
-    # No lcov produced with <9.0, no branch coverage with 10.0 and 11.0.
-    echo "clang versions <9.0 as well as 10.0 and 11.0 are not supported." && return
-  fi
-
-  local -r llvm_profdata="/usr/bin/llvm-profdata"
-  if [[ ! -x ${llvm_profdata} ]]; then
-    return
-  fi
-
-  local -r llvm_cov="/usr/bin/llvm-cov"
-  if [[ ! -x ${llvm_cov} ]]; then
-    return
-  fi
-
+  setup_llvm_coverage_tools_for_lcov || return 0
   setup_external_cc_target
 
-  BAZEL_USE_LLVM_NATIVE_COVERAGE=1 GCOV=$llvm_profdata CC=$clang \
-    BAZEL_LLVM_COV=$llvm_cov bazel coverage --experimental_generate_llvm_lcov \
-      --combined_report=lcov --test_output=all \
-        @other_repo//:t --instrumentation_filter=// &>$TEST_log || fail "Coverage for @other_repo//:t failed"
+  bazel coverage --combined_report=lcov --test_output=all \
+    @other_repo//:t --instrumentation_filter=// &>$TEST_log || fail "Coverage for @other_repo//:t failed"
 
   local expected_result='SF:b.cc
 FN:1,_Z1bb
 FNDA:1,_Z1bb
 FNF:1
 FNH:1
-BRDA:2,0,0,1
-BRDA:2,0,1,0
-BRF:2
-BRH:1
 DA:1,1
 DA:2,1
 DA:3,1
@@ -357,10 +353,6 @@ FN:4,_Z1ab
 FNDA:1,_Z1ab
 FNF:1
 FNH:1
-BRDA:5,0,0,1
-BRDA:5,0,1,0
-BRF:2
-BRH:1
 DA:4,1
 DA:5,1
 DA:6,1
@@ -372,47 +364,22 @@ LH:5
 LF:7
 end_of_record'
 
-  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log))"
-  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat)"
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
+  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat | grep -v '^BR')"
 }
 
 function test_external_cc_target_coverage_not_collected_by_default() {
-  local -r clang="/usr/bin/clang"
-  if [[ ! -x ${clang} ]]; then
-    return
-  fi
-  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
-  if [ "$clang_version" -lt 9 ] || [ "$clang_version" -eq 10 ] || [ "$clang_version" -eq 11 ]; then
-    # No lcov produced with <9.0, no branch coverage with 10.0 and 11.0.
-    echo "clang versions <9.0 as well as 10.0 and 11.0 are not supported." && return
-  fi
-
-  local -r llvm_profdata="/usr/bin/llvm-profdata"
-  if [[ ! -x ${llvm_profdata} ]]; then
-    return
-  fi
-
-  local -r llvm_cov="/usr/bin/llvm-cov"
-  if [[ ! -x ${llvm_cov} ]]; then
-    return
-  fi
-
+  setup_llvm_coverage_tools_for_lcov || return 0
   setup_external_cc_target
 
-  BAZEL_USE_LLVM_NATIVE_COVERAGE=1 GCOV=$llvm_profdata CC=$clang \
-    BAZEL_LLVM_COV=$llvm_cov bazel coverage --experimental_generate_llvm_lcov \
-      --combined_report=lcov --test_output=all \
-        @other_repo//:t &>$TEST_log || fail "Coverage for @other_repo//:t failed"
+  bazel coverage --combined_report=lcov --test_output=all \
+    @other_repo//:t &>$TEST_log || fail "Coverage for @other_repo//:t failed"
 
   local expected_result='SF:b.cc
 FN:1,_Z1bb
 FNDA:1,_Z1bb
 FNF:1
 FNH:1
-BRDA:2,0,0,1
-BRDA:2,0,1,0
-BRF:2
-BRH:1
 DA:1,1
 DA:2,1
 DA:3,1
@@ -424,30 +391,12 @@ LH:5
 LF:7
 end_of_record'
 
-  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log))"
-  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat)"
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
+  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat | grep -v '^BR')"
 }
 
 function test_coverage_with_tmp_in_path() {
-  local -r clang="/usr/bin/clang"
-  if [[ ! -x ${clang} ]]; then
-    return
-  fi
-  local -r clang_version=$(clang --version | grep -o "clang version [0-9]*" | cut -d " " -f 3)
-  if [ "$clang_version" -lt 9 ] || [ "$clang_version" -eq 10 ] || [ "$clang_version" -eq 11 ]; then
-    # No lcov produced with <9.0, no branch coverage with 10.0 and 11.0.
-    echo "clang versions <9.0 as well as 10.0 and 11.0 are not supported." && return
-  fi
-
-  local -r llvm_profdata="/usr/bin/llvm-profdata"
-  if [[ ! -x ${llvm_profdata} ]]; then
-    return
-  fi
-
-  local -r llvm_cov="/usr/bin/llvm-cov"
-  if [[ ! -x ${llvm_cov} ]]; then
-    return
-  fi
+  setup_llvm_coverage_tools_for_lcov || return 0
 
   mkdir -p foo/tmp
   cat > foo/tmp/BUILD <<'EOF'
@@ -490,20 +439,14 @@ int main(void) {
 }
 EOF
 
-  BAZEL_USE_LLVM_NATIVE_COVERAGE=1 GCOV=$llvm_profdata CC=$clang \
-    BAZEL_LLVM_COV=$llvm_cov bazel coverage --experimental_generate_llvm_lcov \
-      --combined_report=lcov --test_output=all \
-        //foo/tmp:t --instrumentation_filter=// &>$TEST_log || fail "Coverage failed"
+  bazel coverage --combined_report=lcov --test_output=all \
+    //foo/tmp:t --instrumentation_filter=// &>$TEST_log || fail "Coverage failed"
 
   local expected_result='SF:foo/tmp/a.cc
 FN:3,_Z1ab
 FNDA:1,_Z1ab
 FNF:1
 FNH:1
-BRDA:4,0,0,1
-BRDA:4,0,1,0
-BRF:2
-BRH:1
 DA:3,1
 DA:4,1
 DA:5,1
@@ -515,8 +458,8 @@ LH:5
 LF:7
 end_of_record'
 
-  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log))"
-  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat)"
+  assert_equals "$expected_result" "$(cat $(get_coverage_file_path_from_test_log) | grep -v '^BR')"
+  assert_equals "$expected_result" "$(cat bazel-out/_coverage/_coverage_report.dat | grep -v '^BR')"
 }
 
 run_suite "test tests"