Support coverage in experimental_ios_test.

Coverage depends on quite a few moving parts, several of which were changed for this test:

- BuildConfiguration.getCoverageLabels() used to include gcov support, this is now replaced by the dedicated getGcovLabels() and a separate implicit attribute on TestBaseRule. This new attribute is then overridden in ExperimentalIosTest to use an xcode-compatible gcov.
- Objc's TestSupport now correctly registers instrumented files and sets the necessary runfiles for collecting coverage.
- ios_test's template exports gcda files for coverage computation after the test's execution.

--
MOS_MIGRATED_REVID=99374435

2 files changed, 32 insertions, 3 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/BaseRuleClasses.java b/src/main/java/com/google/devtools/build/lib/analysis/BaseRuleClasses.java
index 4baf3b3d7e..48887ddf1b 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/BaseRuleClasses.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/BaseRuleClasses.java
@@ -93,7 +93,17 @@ public class BaseRuleClasses {
         @Override
         public List<Label> getDefault(Rule rule, BuildConfiguration configuration) {
           return configuration.isCodeCoverageEnabled()
-              ? ImmutableList.<Label>copyOf(configuration.getCoverageLabels())
+              ? ImmutableList.copyOf(configuration.getCoverageLabels())
+              : ImmutableList.<Label>of();
+        }
+      };
+
+  private static final LateBoundLabelList<BuildConfiguration> GCOV =
+      new LateBoundLabelList<BuildConfiguration>(ImmutableList.of(COVERAGE_SUPPORT_LABEL)) {
+        @Override
+        public List<Label> getDefault(Rule rule, BuildConfiguration configuration) {
+          return configuration.isCodeCoverageEnabled()
+              ? ImmutableList.copyOf(configuration.getGcovLabels())
               : ImmutableList.<Label>of();
         }
       };
@@ -103,7 +113,7 @@ public class BaseRuleClasses {
         @Override
         public List<Label> getDefault(Rule rule, BuildConfiguration configuration) {
           return configuration.isCodeCoverageEnabled()
-              ? ImmutableList.<Label>copyOf(configuration.getCoverageReportGeneratorLabels())
+              ? ImmutableList.copyOf(configuration.getCoverageReportGeneratorLabels())
               : ImmutableList.<Label>of();
         }
       };
@@ -158,6 +168,7 @@ public class BaseRuleClasses {
           // implicitly depend on crosstool, which provides gcov.  We could add gcov to
           // InstrumentedFilesProvider.getInstrumentationMetadataFiles() (or a new method) for
           // all the test rules that have C++ in their transitive closure. Then this could go.
+          .add(attr(":gcov", LABEL_LIST).cfg(HOST).value(GCOV))
           .add(attr(":coverage_support", LABEL_LIST).cfg(HOST).value(COVERAGE_SUPPORT))
           .add(attr(":coverage_report_generator", LABEL_LIST).cfg(HOST)
               .value(COVERAGE_REPORT_GENERATOR))
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
index f8b8199c16..d613f1e37e 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/config/BuildConfiguration.java
@@ -173,13 +173,20 @@ public final class BuildConfiguration {
     }
 
     /**
-     * Returns all the coverage labels for the fragment.
+     * Returns the labels required to run coverage for the fragment.
      */
     public ImmutableList<Label> getCoverageLabels() {
       return ImmutableList.of();
     }
 
     /**
+     * Returns all labels required to run gcov, if provided by this fragment.
+     */
+    public ImmutableList<Label> getGcovLabels() {
+      return ImmutableList.of();
+    }
+
+    /**
      * Returns the coverage report generator tool labels.
      */
     public ImmutableList<Label> getCoverageReportGeneratorLabels() {
@@ -915,6 +922,7 @@ public final class BuildConfiguration {
 
   private final ImmutableSet<Label> coverageLabels;
   private final ImmutableSet<Label> coverageReportGeneratorLabels;
+  private final ImmutableSet<Label> gcovLabels;
 
   // TODO(bazel-team): Move this to a configuration fragment.
   private final PathFragment shExecutable;
@@ -1048,12 +1056,15 @@ public final class BuildConfiguration {
 
     ImmutableSet.Builder<Label> coverageLabelsBuilder = ImmutableSet.builder();
     ImmutableSet.Builder<Label> coverageReportGeneratorLabelsBuilder = ImmutableSet.builder();
+    ImmutableSet.Builder<Label> gcovLabelsBuilder = ImmutableSet.builder();
     for (Fragment fragment : fragments.values()) {
       coverageLabelsBuilder.addAll(fragment.getCoverageLabels());
       coverageReportGeneratorLabelsBuilder.addAll(fragment.getCoverageReportGeneratorLabels());
+      gcovLabelsBuilder.addAll(fragment.getGcovLabels());
     }
     this.coverageLabels = coverageLabelsBuilder.build();
     this.coverageReportGeneratorLabels = coverageReportGeneratorLabelsBuilder.build();
+    this.gcovLabels = gcovLabelsBuilder.build();
 
     this.defaultShellEnvironment = setupShellEnvironment();
 
@@ -1519,6 +1530,13 @@ public final class BuildConfiguration {
   }
 
   /**
+   * Returns the set of labels for gcov.
+   */
+  public Set<Label> getGcovLabels() {
+    return gcovLabels;
+  }
+
+  /**
    * Returns the set of labels for the coverage report generator.
    */
   public Set<Label> getCoverageReportGeneratorLabels() {