Coverage support.

- open source CoverageCommand.java
- add a collect-coverage.sh script
- update test-setup.sh to be compatible with the coverage collector
- update StandaloneTestStrategy to provide the necessary env variables
- update StandaloneTestStrategy to set the right command line for coverage
- add support for C++ coverage

An HTML report can then be generated with genhtml like this:
genhtml -o report/ -p "$(readlink -f bazel-<project>)" path/to/coverage.dat

Progress on #1118.

--
MOS_MIGRATED_REVID=140125715

src/main/java/com/google/devtools/build/lib/rules/test/StandaloneTestStrategy.java

@@ -53,6 +53,8 @@
 @ExecutionStrategy(contextType = TestActionContext.class, name = { "standalone" })
 public class StandaloneTestStrategy extends TestStrategy {
   // TODO(bazel-team) - add tests for this strategy.
+  private static final String COLLECT_COVERAGE =
+      "external/bazel_tools/tools/coverage/collect-coverage.sh";
 
   private final Path workspace;
 
@@ -100,9 +102,7 @@ public void exec(TestRunnerAction action, ActionExecutionContext actionExecution
     Artifact testSetup = action.getRuntimeArtifact(TEST_SETUP_BASENAME);
     Spawn spawn =
         new BaseSpawn(
-            // Bazel lacks much of the tooling for coverage, so we don't attempt to pass a coverage
-            // script here.
-            getArgs(testSetup.getExecPathString(), "", action),
+            getArgs(testSetup.getExecPathString(), COLLECT_COVERAGE, action),
             env,
             info,
             new RunfilesSupplierImpl(
@@ -172,7 +172,13 @@ private Map<String, String> getEnv(
     if (!action.isEnableRunfiles()) {
       vars.put("RUNFILES_MANIFEST_ONLY", "1");
     }
-
+    if (isCoverageMode(action)) {
+      vars.put("COVERAGE_MANIFEST",
+          action.getExecutionSettings().getInstrumentedFileManifest().getExecPathString());
+      vars.put("COVERAGE_OUTPUT_FILE", action.getCoverageData().getExecPathString());
+      // Instruct test-setup.sh not to cd into the runfiles directory.
+      vars.put("RUNTEST_PRESERVE_CWD", "1");
+    }
     return vars;
   }
 

src/main/java/com/google/devtools/build/lib/runtime/commands/coverage.txt

@@ -0,0 +1,15 @@
+
+Usage: blaze %{command} <options> <test-targets>
+
+Builds and runs the specified test targets using the specified options while
+collecting code coverage statistics. Optionally, it also generates combined
+HTML report containing coverage results for all executed tests.
+
+This command accepts all valid options to 'test' and 'build', and inherits
+defaults for 'test' (and 'build') from your .blazerc.  If you don't use
+.blazerc, don't forget to pass all your 'build' options to '%{command}' too.
+
+See 'blaze help target-syntax' for details and examples on how to
+specify targets.
+
+%{options}

tools/BUILD

@@ -16,6 +16,7 @@ filegroup(
         "//tools/build_defs/pkg:srcs",
         "//tools/build_defs/repo:srcs",
         "//tools/build_rules:srcs",
+        "//tools/coverage:srcs",
         "//tools/proto/toolchains:srcs",
         "//tools/ide:srcs",
         "//tools/jdk:srcs",
@@ -42,6 +43,7 @@ filegroup(
         "//tools/build_defs/repo:srcs",
         "//tools/build_rules:embedded_tools_srcs",
         "//tools/buildstamp:srcs",
+        "//tools/coverage:srcs",
         "//tools/proto/toolchains:srcs",
         "//tools/cpp:srcs",
         "//tools/genrule:srcs",

tools/coverage/BUILD

@@ -0,0 +1,16 @@
+package(default_visibility = ["//visibility:public"])
+
+filegroup(
+    name = "coverage_support",
+    srcs = ["collect-coverage.sh"],
+)
+
+filegroup(
+    name = "coverage_report_generator",
+    srcs = ["dummy_coverage_report_generator"],
+)
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["*"]),
+)

tools/coverage/collect-coverage.sh

@@ -0,0 +1,72 @@
+#!/bin/bash
+
+# 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.
+
+ROOT="$PWD"
+if [[ $COVERAGE_OUTPUT_FILE != /* ]]; then
+  COVERAGE_OUTPUT_FILE="${ROOT}/${COVERAGE_OUTPUT_FILE}"
+fi
+if [[ "$COVERAGE_MANIFEST" != /* ]]; then
+  export COVERAGE_MANIFEST="${ROOT}/${COVERAGE_MANIFEST}"
+fi
+
+export COVERAGE_DIR="$(mktemp -d ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX)"
+trap "{ rm -rf ${COVERAGE_DIR} }" EXIT
+
+# C++ env variables
+export GCOV_PREFIX_STRIP=3
+export GCOV_PREFIX="${COVERAGE_DIR}"
+
+touch "${COVERAGE_OUTPUT_FILE}"
+
+DIR="$TEST_SRCDIR"
+if [ ! -z "$TEST_WORKSPACE" ]; then
+  DIR="$DIR"/"$TEST_WORKSPACE"
+fi
+cd "$DIR" || { echo "Could not chdir $DIR"; exit 1; }
+"$@"
+TEST_STATUS=$?
+
+if [[ ${TEST_STATUS} -ne 0 ]]; then
+  echo "--"
+  echo "Coverage runner: Not collecting coverage for failed test."
+  echo "The following commands failed with status ${TEST_STATUS}:"
+  echo "$@"
+  exit ${TEST_STATUS}
+fi
+
+echo "--"
+echo "Post-processing coverage results:"
+
+cat "${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}"
+

tools/test/BUILD

@@ -9,12 +9,12 @@ filegroup(
 
 filegroup(
     name = "coverage_support",
-    srcs = [],
+    srcs = ["//tools/coverage:coverage_support"],
 )
 
 filegroup(
     name = "coverage_report_generator",
-    srcs = ["dummy_coverage_report_generator"],
+    srcs = ["//tools/coverage:coverage_report_generator"],
 )
 
 filegroup(

tools/test/test-setup.sh

@@ -46,21 +46,20 @@ if [[ -n "${TEST_TOTAL_SHARDS+x}" ]] && ((TEST_TOTAL_SHARDS != 0)); then
 fi
 export GTEST_TMP_DIR="${TEST_TMPDIR}"
 
-DIR="$TEST_SRCDIR"
-RUNFILES_MANIFEST_FILE=$DIR/MANIFEST
+RUNFILES_MANIFEST_FILE="${TEST_SRCDIR}/MANIFEST"
 
 if [ -z "$RUNFILES_MANIFEST_ONLY" ]; then
   function rlocation() {
     if [[ "$1" = /* ]]; then
-      echo $1
+      echo "$1"
     else
       echo "$(dirname $RUNFILES_MANIFEST_FILE)/$1"
     fi
   }
 else
   function rlocation() {
     if [[ "$1" = /* ]]; then
-      echo $1
+      echo "$1"
     else
       echo $(grep "^$1 " $RUNFILES_MANIFEST_FILE | awk '{ print $2 }')
     fi
@@ -70,11 +69,11 @@ fi
 export -f rlocation
 export RUNFILES_MANIFEST_FILE
 
-if [ ! -z "$TEST_WORKSPACE" ]
-then
+DIR="$TEST_SRCDIR"
+if [ ! -z "$TEST_WORKSPACE" ]; then
   DIR="$DIR"/"$TEST_WORKSPACE"
 fi
-
+[[ -n "$RUNTEST_PRESERVE_CWD" ]] && DIR="$PWD"
 
 
 # normal commands are run in the exec-root where they have access to
@@ -100,6 +99,7 @@ if [[ "$TEST_NAME" = /* ]]; then
 else
   EXE="$(rlocation $TEST_WORKSPACE/$TEST_NAME)"
 fi
+[[ -n "$RUNTEST_PRESERVE_CWD" ]] && EXE="${TEST_NAME}"
 
 exitCode=0
 "${EXE}" "$@" || exitCode=$?