Move C++ coverage collection logic out of collect_coverage.sh
This PR pulls the C++ code coverage collection logic out of `toos/test/of collect_coverage.sh` and moves it to a new script `tools/test/collect_cc_coverage.sh`. There are 2 reasons for this:
* to make the scripts easier to understand and maintain
* in preparation for having a more general code collection logic
This PR does not change the behavior of Bazel, is just a no-op refactoring.
Progress on #5882
Closes #5801.
PiperOrigin-RevId: 209923852
diff --git a/tools/test/collect_cc_coverage.sh b/tools/test/collect_cc_coverage.sh
new file mode 100755
index 0000000..c0d6b36
--- /dev/null
+++ b/tools/test/collect_cc_coverage.sh
@@ -0,0 +1,100 @@
+#!/bin/bash -x
+ # Copyright 2016 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script collects code coverage data for C++ sources, after the tests
+# were executed.
+#
+# Bazel C++ code coverage collection support is poor and limited. There is
+# an ongoing effort to improve this (tracking issue #1118).
+#
+# Bazel uses the lcov tool for gathering coverage data. There is also
+# an experimental support for clang llvm coverage, which uses the .profraw
+# data files to compute the coverage report.
+#
+# This script assumes the following environment variables are set:
+# - COVERAGE_DIR Directory containing metadata files needed for
+# coverage collection (e.g. gcda files, profraw).
+# - COVERAGE_MANIFEST Location of the instrumented file manifest.
+# - COVERAGE_OUTPUT_FILE Location of the final coverage report.
+# - COVERAGE_GCOV_PATH Location of gcov. This is set by the TestRunner.
+# - ROOT Location from where the code coverage collection
+# was invoked.
+#
+# 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.
+# The coverage data is placed in $COVERAGE_OUTPUT_FILE.
+
+# Checks if clang llvm coverage should be used instead of lcov.
+function uses_llvm() {
+ if stat "${COVERAGE_DIR}"/*.profraw >/dev/null 2>&1; then
+ return 0
+ fi
+ return 1
+}
+
+function init_gcov() {
+ # Symlink the gcov tool such with a link called gcov. Clang comes with a tool
+ # called llvm-cov, which behaves like gcov if symlinked in this way (otherwise
+ # we would need to invoke it with "llvm-cov gcov").
+ # For more details see https://llvm.org/docs/CommandGuide/llvm-cov.html.
+ GCOV="${COVERAGE_DIR}/gcov"
+ ln -s "${COVERAGE_GCOV_PATH}" "${GCOV}"
+}
+
+# Computes code coverage data using the clang generated metadata found under $COVERAGE_DIR.
+# Writes the collected coverage into ${COVERAGE_OUTPUT_FILE}.
+function llvm_coverage() {
+ export LLVM_PROFILE_FILE="${COVERAGE_DIR}/%h-%p-%m.profraw"
+ "${COVERAGE_GCOV_PATH}" merge -output "${COVERAGE_OUTPUT_FILE}" "${COVERAGE_DIR}"/*.profraw
+}
+
+# Computes code coverage data using gcda files found under $COVERAGE_DIR.
+# Writes the collected coverage into ${COVERAGE_OUTPUT_FILE} in lcov format.
+function lcov_coverage() {
+ cat "${COVERAGE_MANIFEST}" | grep ".gcno$" | while read gcno; do
+ mkdir -p "${COVERAGE_DIR}/$(dirname ${gcno})"
+ cp "${ROOT}/${gcno}" "${COVERAGE_DIR}/${gcno}"
+ done
+ # Run lcov over the .gcno and .gcda files to generate the lcov tracefile.
+ # -c - Collect coverage data
+ # --no-external - Do not collect coverage data for system files
+ # --ignore-errors graph - Ignore missing .gcno files; Bazel only instruments some files
+ # -q - Quiet mode
+ # --gcov-tool "${GCOV}" - Pass the local symlink to be uses as gcov by lcov
+ # -b /proc/self/cwd - Use this as a prefix for all source files instead of
+ # the current directory
+ # -d "${COVERAGE_DIR}" - Directory to search for .gcda files
+ # -o "${COVERAGE_OUTPUT_FILE}" - Output file
+ LCOV=$(which lcov)
+ if [[ ! -x $LCOV ]]; then
+ LCOV=/usr/bin/lcov
+ fi
+ $LCOV -c --no-external --ignore-errors graph -q \
+ --gcov-tool "${GCOV}" -b /proc/self/cwd \
+ -d "${COVERAGE_DIR}" -o "${COVERAGE_OUTPUT_FILE}"
+ # Fix up the paths to be relative by removing the prefix we specified above.
+ sed -i -e "s*/proc/self/cwd/**g" "${COVERAGE_OUTPUT_FILE}"
+}
+
+function main() {
+ init_gcov
+ if uses_llvm; then
+ llvm_coverage
+ else
+ lcov_coverage
+ fi
+}
+
+main
\ No newline at end of file
