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

7 files changed, 134 insertions, 13 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() {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
index 06c9e6b9cc..a32c11697b 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/cpp/CppConfiguration.java
@@ -1806,7 +1806,7 @@ public class CppConfiguration extends BuildConfiguration.Fragment {
   }
 
   @Override
-  public ImmutableList<Label> getCoverageLabels() {
+  public ImmutableList<Label> getGcovLabels() {
     // TODO(bazel-team): Using a gcov-specific crosstool filegroup here could reduce the number of
     // inputs significantly. We'd also need to add logic in tools/coverage/collect_coverage.sh to
     // drop crosstool dependency if metadataFiles does not contain *.gcno artifacts.
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTest.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTest.java
index 5bbd81f126..4147412439 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTest.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTest.java
@@ -40,14 +40,13 @@ public final class ExperimentalIosTest extends IosTest {
 
     Runfiles.Builder runfilesBuilder = new Runfiles.Builder()
         .addRunfiles(ruleContext, RunfilesProvider.DEFAULT_RUNFILES);
-    NestedSetBuilder<Artifact> filesToBuildBuilder = NestedSetBuilder.<Artifact>stableOrder();
-    filesToBuildBuilder.addTransitive(filesToBuild);
+    NestedSetBuilder<Artifact> filesToBuildBuilder = NestedSetBuilder.<Artifact>stableOrder()
+        .addTransitive(filesToBuild);
 
-    TestSupport testSupport =
-        new TestSupport(ruleContext)
-            .registerTestRunnerActions()
-            .addRunfiles(runfilesBuilder)
-            .addFilesToBuild(filesToBuildBuilder);
+    TestSupport testSupport = new TestSupport(ruleContext)
+        .registerTestRunnerActions()
+        .addRunfiles(runfilesBuilder, common.getObjcProvider())
+        .addFilesToBuild(filesToBuildBuilder);
 
     Artifact executable = testSupport.generatedTestScript();
 
@@ -61,6 +60,7 @@ public final class ExperimentalIosTest extends IosTest {
         .add(RunfilesProvider.class, RunfilesProvider.simple(runfiles))
         .add(ExecutionInfoProvider.class,
             new ExecutionInfoProvider(ImmutableMap.of(ExecutionRequirements.REQUIRES_DARWIN, "")))
+        .addProviders(testSupport.getExtraProviders(common.getObjcProvider()))
         .setRunfilesSupport(runfilesSupport, executable)
         .build();
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTestRule.java b/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTestRule.java
index 2a866b720c..7bf6ec2993 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTestRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/ExperimentalIosTestRule.java
@@ -14,20 +14,28 @@
 
 package com.google.devtools.build.lib.rules.objc;
 
+import static com.google.devtools.build.lib.packages.Attribute.ConfigurationTransition.HOST;
 import static com.google.devtools.build.lib.packages.Attribute.attr;
 import static com.google.devtools.build.lib.packages.Type.LABEL;
 import static com.google.devtools.build.lib.packages.Type.LABEL_LIST;
 import static com.google.devtools.build.lib.packages.Type.STRING_LIST;
 
+import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.Constants;
 import com.google.devtools.build.lib.analysis.BaseRuleClasses;
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration;
+import com.google.devtools.build.lib.packages.Attribute.LateBoundLabelList;
 import com.google.devtools.build.lib.packages.ImplicitOutputsFunction;
+import com.google.devtools.build.lib.packages.Rule;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
+import com.google.devtools.build.lib.syntax.Label;
 import com.google.devtools.build.lib.util.FileType;
 
+import java.util.List;
+
 /**
  * Rule definition for {@code experimental_ios_test} rule in Bazel.
  *
@@ -78,6 +86,17 @@ public final class ExperimentalIosTestRule implements RuleDefinition {
         .add(attr("$test_template", LABEL)
             .value(env.getLabel("//tools/objc:ios_test.sh.bazel_template")))
         .add(attr("$test_runner", LABEL).value(env.getLabel("//tools/objc:testrunner")))
+        .override(attr(":gcov", LABEL_LIST).cfg(HOST)
+            .value(new LateBoundLabelList<BuildConfiguration>() {
+              @Override
+              public List<Label> getDefault(Rule rule, BuildConfiguration configuration) {
+                if (!configuration.isCodeCoverageEnabled()) {
+                  return ImmutableList.of();
+                }
+                return ImmutableList.of(
+                    configuration.getFragment(ObjcConfiguration.class).getGcovLabel());
+              }
+            }))
         .build();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/TestSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/TestSupport.java
index f1774e4bb0..5506115905 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/TestSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/TestSupport.java
@@ -18,22 +18,28 @@ import com.google.common.base.Joiner;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.FileProvider;
 import com.google.devtools.build.lib.analysis.PrerequisiteArtifacts;
 import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.analysis.RuleContext;
-import com.google.devtools.build.lib.analysis.Runfiles;
+import com.google.devtools.build.lib.analysis.Runfiles.Builder;
 import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.analysis.TransitiveInfoProvider;
 import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction;
 import com.google.devtools.build.lib.analysis.actions.TemplateExpansionAction.Substitution;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.packages.Type;
+import com.google.devtools.build.lib.rules.objc.ObjcProvider.Key;
+import com.google.devtools.build.lib.rules.test.InstrumentedFilesProvider;
+import com.google.devtools.build.lib.rules.test.InstrumentedFilesProviderImpl;
 import com.google.devtools.build.lib.util.FileType;
 
 import java.util.List;
+import java.util.Map;
 
 import javax.annotation.Nullable;
 
@@ -184,8 +190,10 @@ class TestSupport {
 
   /**
    * Adds all files needed to run this test to the passed Runfiles builder.
+   *
+   * @param objcProvider common information about this rule's attributes and its dependencies
    */
-  TestSupport addRunfiles(Runfiles.Builder runfilesBuilder) {
+  TestSupport addRunfiles(Builder runfilesBuilder, ObjcProvider objcProvider) {
     runfilesBuilder
         .addArtifact(testIpa())
         .addArtifacts(xctestIpa().asSet())
@@ -199,10 +207,71 @@ class TestSupport {
     } else {
       runfilesBuilder.addTransitiveArtifacts(labDeviceRunfiles());
     }
+
+    if (ruleContext.getConfiguration().isCodeCoverageEnabled()) {
+      runfilesBuilder
+          .addTransitiveArtifacts(objcProvider.get(ObjcProvider.SOURCE))
+          .addTransitiveArtifacts(gcnoFiles(objcProvider));
+    }
     return this;
   }
 
   /**
+   * Returns any additional providers that need to be exported to the rule context to the passed
+   * builder.
+   *
+   * @param objcProvider common information about this rule's attributes and its dependencies
+   */
+  public Map<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>
+      getExtraProviders(ObjcProvider objcProvider) {
+    return ImmutableMap.<Class<? extends TransitiveInfoProvider>, TransitiveInfoProvider>of(
+        InstrumentedFilesProvider.class,
+        new InstrumentedFilesProviderImpl(
+            instrumentedFiles(objcProvider), gcnoFiles(objcProvider), gcovEnv()));
+  }
+
+  /**
+   * Returns a map of extra environment variable names to their values used to point to gcov binary,
+   * which should be added to the test action environment, if coverage is enabled.
+   */
+  private Map<String, String> gcovEnv() {
+    if (ruleContext.getConfiguration().isCodeCoverageEnabled()) {
+      return ImmutableMap.of("COVERAGE_GCOV_PATH",
+          ruleContext.getHostPrerequisiteArtifact(":gcov").getExecPathString());
+    }
+    return ImmutableMap.of();
+  }
+
+  /**
+   * Returns all GCC coverage notes files available for computing coverage.
+   */
+  private NestedSet<Artifact> gcnoFiles(ObjcProvider objcProvider) {
+    return filesWithXcTestApp(ObjcProvider.GCNO, objcProvider);
+  }
+
+  /**
+   * Returns all source files from the test (and if present xctest app) which have been
+   * instrumented for code coverage.
+   */
+  private NestedSet<Artifact> instrumentedFiles(ObjcProvider objcProvider) {
+    return filesWithXcTestApp(ObjcProvider.INSTRUMENTED_SOURCE, objcProvider);
+  }
+
+  private NestedSet<Artifact> filesWithXcTestApp(Key<Artifact> key, ObjcProvider objcProvider) {
+    NestedSet<Artifact> underlying = objcProvider.get(key);
+    XcTestAppProvider provider = ruleContext.getPrerequisite(
+        IosTest.XCTEST_APP, Mode.TARGET, XcTestAppProvider.class);
+    if (provider == null) {
+      return underlying;
+    }
+
+    return NestedSetBuilder.<Artifact>stableOrder()
+        .addTransitive(underlying)
+        .addTransitive(provider.getObjcProvider().get(key))
+        .build();
+  }
+
+  /**
    * Jar files for plugins to the test runner. May be empty.
    */
   private NestedSet<Artifact> plugins() {
diff --git a/src/main/java/com/google/devtools/build/lib/rules/test/TestActionBuilder.java b/src/main/java/com/google/devtools/build/lib/rules/test/TestActionBuilder.java
index f7393322f1..958e8b3779 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/test/TestActionBuilder.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/test/TestActionBuilder.java
@@ -209,6 +209,10 @@ public final class TestActionBuilder {
           ruleContext.getPrerequisites(":coverage_support", Mode.HOST)) {
         inputsBuilder.addTransitive(dep.getProvider(FileProvider.class).getFilesToBuild());
       }
+      for (TransitiveInfoCollection dep :
+          ruleContext.getPrerequisites(":gcov", Mode.HOST)) {
+        inputsBuilder.addTransitive(dep.getProvider(FileProvider.class).getFilesToBuild());
+      }
       Artifact instrumentedFileManifest =
           InstrumentedFileManifestAction.getInstrumentedFileManifest(ruleContext,
               ImmutableList.copyOf(instrumentedFiles.getInstrumentedFiles()),