coverage: use LLVM coverage

bazel/BUILD

@@ -85,6 +85,11 @@ config_setting(
     values = {"define": "ENVOY_CONFIG_COVERAGE=1"},
 )
 
+config_setting(
+    name = "coverage_llvm_build",
+    values = {"define": "ENVOY_CONFIG_COVERAGE=llvm"},
+)
+
 config_setting(
     name = "disable_tcmalloc",
     values = {"define": "tcmalloc=disabled"},

bazel/envoy_binary.bzl

@@ -67,6 +67,12 @@ def _envoy_linkopts():
                    "-ldl",
                    "-Wl,--hash-style=gnu",
                ],
+           }) + select({
+               "@envoy//bazel:coverage_llvm_build": [
+                   "-fprofile-instr-generate",
+                   "-fcoverage-mapping",
+               ],
+               "//conditions:default": [],
            }) + envoy_static_link_libstdcpp_linkopts() + \
            _envoy_select_exported_symbols(["-Wl,-E"])
 

bazel/envoy_library.bzl

@@ -47,7 +47,13 @@ def envoy_cc_library(
         name = name,
         srcs = srcs,
         hdrs = hdrs,
-        copts = envoy_copts(repository) + copts,
+        copts = envoy_copts(repository) + copts + select({
+            repository + "//bazel:coverage_llvm_build": [
+                "-fprofile-instr-generate",
+                "-fcoverage-mapping",
+            ],
+            "//conditions:default": [],
+        }),
         visibility = visibility,
         tags = tags,
         textual_hdrs = textual_hdrs,

bazel/envoy_test.bzl

@@ -60,6 +60,12 @@ def _envoy_test_linkopts():
         # TODO(mattklein123): It's not great that we universally link against the following libs.
         # In particular, -latomic and -lrt are not needed on all platforms. Make this more granular.
         "//conditions:default": ["-pthread", "-lrt", "-ldl"],
+    }) + select({
+        "@envoy//bazel:coverage_llvm_build": [
+            "-fprofile-instr-generate",
+            "-fcoverage-mapping",
+        ],
+        "//conditions:default": [],
     }) + envoy_select_force_libcpp([], ["-lstdc++fs", "-latomic"])
 
 # Envoy C++ fuzz test targets. These are not included in coverage runs.

ci/do_ci.sh

@@ -241,24 +241,13 @@ elif [[ "$CI_TARGET" == "bazel.api" ]]; then
     @envoy_api//tools:tap2pcap_test
   exit 0
 elif [[ "$CI_TARGET" == "bazel.coverage" ]]; then
-  setup_gcc_toolchain
+  setup_clang_toolchain
   echo "bazel coverage build with tests ${TEST_TARGETS}"
 
-  # gcovr is a pain to run with `bazel run`, so package it up into a
-  # relocatable and hermetic-ish .par file.
-  bazel build --python_version=PY2 @com_github_gcovr_gcovr//:gcovr.par
-  export GCOVR="/tmp/gcovr.par"
-  cp -f "${ENVOY_SRCDIR}/bazel-bin/external/com_github_gcovr_gcovr/gcovr.par" ${GCOVR}
-
-  # Reduce the amount of memory and number of cores Bazel tries to use to
-  # prevent it from launching too many subprocesses. This should prevent the
-  # system from running out of memory and killing tasks. See discussion on
-  # https://github.com/envoyproxy/envoy/pull/5611.
-  # TODO(akonradi): use --local_cpu_resources flag once Bazel has a release
-  # after 0.21.
-  [ -z "$CIRCLECI" ] || export BAZEL_BUILD_OPTIONS="${BAZEL_BUILD_OPTIONS} --local_resources=12288,4,1"
+  # LLVM coverage is a memory hog too.
+  [ -z "$CIRCLECI" ] || export BAZEL_BUILD_OPTIONS="${BAZEL_BUILD_OPTIONS} --local_cpu_resources=6"
 
-  test/run_envoy_bazel_coverage.sh ${TEST_TARGETS}
+  test/run_envoy_bazel_llvm_coverage.sh ${TEST_TARGETS}
   collect_build_profile coverage
   exit 0
 elif [[ "$CI_TARGET" == "bazel.clang_tidy" ]]; then

test/run_envoy_bazel_llvm_coverage.sh

@@ -0,0 +1,43 @@
+#!/bin/bash
+
+set -e
+
+[[ -z "${SRCDIR}" ]] && SRCDIR="${PWD}"
+[[ -z "${BAZEL_COVERAGE}" ]] && BAZEL_COVERAGE=bazel
+
+echo "Starting run_envoy_bazel_coverage.sh..."
+echo "    PWD=$(pwd)"
+echo "    SRCDIR=${SRCDIR}"
+echo "    BAZEL_COVERAGE=${BAZEL_COVERAGE}"
+echo "    VALIDATE_COVERAGE=${VALIDATE_COVERAGE}"
+
+# This is the target that will be run to generate coverage data. It can be overridden by consumer
+# projects that want to run coverage on a different/combined target.
+# Command-line arguments take precedence over ${COVERAGE_TARGET}.
+if [[ $# -gt 0 ]]; then
+  COVERAGE_TARGETS=$*
+elif [[ -n "${COVERAGE_TARGET}" ]]; then
+  COVERAGE_TARGETS=${COVERAGE_TARGET}
+else
+  COVERAGE_TARGETS="//test/... @com_googlesource_quiche//:all"
+fi
+
+rm -rf $(find -L bazel-bin -name "test-*.profraw")
+
+"${BAZEL_COVERAGE}" test "${COVERAGE_TARGETS}" ${BAZEL_BUILD_OPTIONS} -c fastbuild --copt=-DNDEBUG \
+  --cache_test_results=no --define ENVOY_CONFIG_COVERAGE=llvm --cxxopt="-DENVOY_CONFIG_COVERAGE=1" \
+  --test_output=all --strategy=TestRunner=local --test_filter='-QuicPlatformTest.QuicStackTraceTest' \
+  --test_env=LLVM_PROFILE_FILE=test-%p.profraw --test_arg="--log-path /dev/null" --test_arg="-l trace"
+
+COVERAGE_DIR="${SRCDIR}"/generated/coverage
+mkdir -p "${COVERAGE_DIR}"
+
+echo "Merging profile data..."
+llvm-profdata merge -sparse $(find -L bazel-bin -name "test-*.profraw") -o ${COVERAGE_DIR}/coverage.profdata
+
+echo "Generating report..."
+llvm-cov show bazel-bin/source/exe/envoy-static -instr-profile=${COVERAGE_DIR}/coverage.profdata \
+  -ignore-filename-regex='(/external/|pb\.(validate\.)?(h|cc)|/chromium_url/)' -output-dir=${COVERAGE_DIR} -format=html
+sed -i -e 's|>bazel-out/[^/]*/bin/\([^/]*\)/[^<]*/_virtual_includes/[^/]*|>\1|g' "${COVERAGE_DIR}/index.html"
+
+[[ -z "${ENVOY_COVERAGE_DIR}" ]] || rsync -av "${COVERAGE_DIR}"/ "${ENVOY_COVERAGE_DIR}"