Add functionality from the old shell-based coverage runner script to the new one.

This isn't a principled solution, but since it depends on /usr/bin/lcov, it should never be relied on at all. It's mostly a courtesy to people who came to use C++ coverage in Bazel before we removed it.

Fixes #2685.

Progress on #1118.

RELNOTES: None.
PiperOrigin-RevId: 156866370

1 files changed, 44 insertions, 8 deletions

diff --git a/tools/test/collect_coverage.sh b/tools/test/collect_coverage.sh
index 33aa2e373c..b8e1dc7ddb 100755
--- a/tools/test/collect_coverage.sh
+++ b/tools/test/collect_coverage.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/bash -x
 
 # Copyright 2016 The Bazel Authors. All rights reserved.
 #
@@ -25,6 +25,15 @@
 # Script expects that it will be started in the execution root directory and
 # not in the test's runfiles directory.
 
+if [[ -z "$LCOV_MERGER" ]]; then
+  echo --
+  echo "Coverage collection running in legacy mode."
+  echo "Legacy mode only supports C++ and even then, it's very brittle."
+  COVERAGE_LEGACY_MODE=1
+else
+  COVERAGE_LEGACY_MODE=
+fi
+
 if [[ -z "$COVERAGE_MANIFEST" ]]; then
   echo --
   echo Coverage runner: \$COVERAGE_MANIFEST is not set
@@ -66,7 +75,7 @@ export BULK_COVERAGE_RUN=1
 
 
 # Only check if file exists when LCOV_MERGER is set
-if [[ ! -z "$LCOV_MERGER" ]]; then
+if [[ ! "$COVERAGE_LEGACY_MODE" ]]; then
   for name in "$LCOV_MERGER"; do
     if [[ ! -e $name ]]; then
       echo --
@@ -76,17 +85,15 @@ if [[ ! -z "$LCOV_MERGER" ]]; then
   done
 fi
 
+if [[ "$COVERAGE_LEGACY_MODE" ]]; then
+  export GCOV_PREFIX_STRIP=3
+  export GCOV_PREFIX="${COVERAGE_DIR}"
+fi
 
 cd "$TEST_SRCDIR"
 "$@"
 TEST_STATUS=$?
 
-# If LCOV_MERGER is not set, coverage is not supported.
-if [[ -z "$LCOV_MERGER" ]]; then
-  exit $TEST_STATUS
-fi
-
-
 # always create output files
 touch $COVERAGE_OUTPUT_FILE
 
@@ -100,6 +107,35 @@ fi
 
 cd $ROOT
 
+# If LCOV_MERGER is not set, use the legacy, awful, C++-only method to convert
+# coverage files.
+# NB: This is here just so that we don't regress. Do not add support for new
+# coverage features here. Implement it instead properly in LcovMerger.
+if [[ "$COVERAGE_LEGACY_MODE" ]]; then
+  cat "${COVERAGE_MANIFEST}" | grep ".gcno$" | while read path; do
+    mkdir -p "${COVERAGE_DIR}/$(dirname ${path})"
+    cp "${ROOT}/${path}" "${COVERAGE_DIR}/${path}"
+  done
+
+  # Unfortunately, lcov messes up the source file names if it can't find the
+  # files at their relative paths. Workaround by creating empty source files
+  # according to the manifest (i.e., only for files that are supposed to be
+  # instrumented).
+  cat "${COVERAGE_MANIFEST}" | egrep ".(cc|h)$" | while read path; do
+    mkdir -p "${COVERAGE_DIR}/$(dirname ${path})"
+    touch "${COVERAGE_DIR}/${path}"
+  done
+
+  # Run lcov over the .gcno and .gcda files to generate the lcov tracefile.
+  /usr/bin/lcov -c --no-external -d "${COVERAGE_DIR}" -o "${COVERAGE_OUTPUT_FILE}"
+
+  # The paths are all wrong, because they point to /tmp. Fix up the paths to
+  # point to the exec root instead (${ROOT}).
+  sed -i -e "s*${COVERAGE_DIR}*${ROOT}*g" "${COVERAGE_OUTPUT_FILE}"
+
+  exit $TEST_STATUS
+fi
+
 export LCOV_MERGER_CMD="java -jar ${LCOV_MERGER} --coverage_dir=${COVERAGE_DIR} \
 --output_file=${COVERAGE_OUTPUT_FILE}"