From ca4e13ac57d5c4c44cc4e4618522799cfde96ab3 Mon Sep 17 00:00:00 2001
From: Michael Thvedt <mthvedt@google.com>
Date: Thu, 18 Jun 2015 17:56:11 +0000
Subject: Move J2ObjCLibrary and supporting classes to Bazel, and enable J2ObJC
 in Bazel.

--
MOS_MIGRATED_REVID=96324830
---
 .../lib/bazel/rules/BazelRuleClassProvider.java    |   8 +-
 .../lib/bazel/rules/java/BazelJavaLibraryRule.java |   7 +
 .../lib/rules/java/J2ObjcCommandLineOptions.java   |  50 ++++
 .../build/lib/rules/java/J2ObjcConfiguration.java  | 130 ++++++++++
 .../build/lib/rules/java/JavaImportBaseRule.java   |   4 +
 .../lib/rules/objc/BazelJ2ObjcLibraryRule.java     |  55 ++++
 .../build/lib/rules/objc/CompilationSupport.java   |   1 +
 .../build/lib/rules/objc/J2ObjcAspect.java         | 282 +++++++++++++++++++++
 .../lib/rules/objc/J2ObjcCommandLineOptions.java   |  48 ----
 .../build/lib/rules/objc/J2ObjcConfiguration.java  | 128 ----------
 .../build/lib/rules/objc/J2ObjcLibrary.java        | 110 ++++++++
 .../lib/rules/objc/J2ObjcLibraryBaseRule.java      |  79 ++++++
 12 files changed, 724 insertions(+), 178 deletions(-)
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcCommandLineOptions.java
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcConfiguration.java
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/BazelJ2ObjcLibraryRule.java
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcAspect.java
 delete mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
 delete mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcConfiguration.java
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibrary.java
 create mode 100644 src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryBaseRule.java

diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
index dabf2fe27c..dfbcc4244a 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/BazelRuleClassProvider.java
@@ -80,6 +80,8 @@ import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 import com.google.devtools.build.lib.rules.cpp.CppConfigurationLoader;
 import com.google.devtools.build.lib.rules.cpp.CppOptions;
 import com.google.devtools.build.lib.rules.genquery.GenQueryRule;
+import com.google.devtools.build.lib.rules.java.J2ObjcCommandLineOptions;
+import com.google.devtools.build.lib.rules.java.J2ObjcConfiguration;
 import com.google.devtools.build.lib.rules.java.JavaConfiguration;
 import com.google.devtools.build.lib.rules.java.JavaConfigurationLoader;
 import com.google.devtools.build.lib.rules.java.JavaCpuSupplier;
@@ -88,13 +90,13 @@ import com.google.devtools.build.lib.rules.java.JavaOptions;
 import com.google.devtools.build.lib.rules.java.JavaToolchainRule;
 import com.google.devtools.build.lib.rules.java.Jvm;
 import com.google.devtools.build.lib.rules.java.JvmConfigurationLoader;
+import com.google.devtools.build.lib.rules.objc.BazelJ2ObjcLibraryRule;
 import com.google.devtools.build.lib.rules.objc.ExperimentalIosTestRule;
 import com.google.devtools.build.lib.rules.objc.IosApplicationRule;
 import com.google.devtools.build.lib.rules.objc.IosDeviceRule;
 import com.google.devtools.build.lib.rules.objc.IosExtensionBinaryRule;
 import com.google.devtools.build.lib.rules.objc.IosExtensionRule;
-import com.google.devtools.build.lib.rules.objc.J2ObjcCommandLineOptions;
-import com.google.devtools.build.lib.rules.objc.J2ObjcConfiguration;
+import com.google.devtools.build.lib.rules.objc.J2ObjcLibraryBaseRule;
 import com.google.devtools.build.lib.rules.objc.ObjcBinaryRule;
 import com.google.devtools.build.lib.rules.objc.ObjcBuildInfoFactory;
 import com.google.devtools.build.lib.rules.objc.ObjcBundleLibraryRule;
@@ -329,6 +331,8 @@ public class BazelRuleClassProvider {
     builder.addRuleDefinition(new IosApplicationRule());
     builder.addRuleDefinition(new IosExtensionBinaryRule());
     builder.addRuleDefinition(new IosExtensionRule());
+    builder.addRuleDefinition(new J2ObjcLibraryBaseRule());
+    builder.addRuleDefinition(new BazelJ2ObjcLibraryRule());
 
     builder.addRuleDefinition(new BazelExtraActionRule());
     builder.addRuleDefinition(new BazelActionListenerRule());
diff --git a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaLibraryRule.java b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaLibraryRule.java
index acc91733ac..6e7f85a8a9 100644
--- a/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaLibraryRule.java
+++ b/src/main/java/com/google/devtools/build/lib/bazel/rules/java/BazelJavaLibraryRule.java
@@ -25,6 +25,10 @@ import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
 import com.google.devtools.build.lib.bazel.rules.java.BazelJavaRuleClasses.JavaRule;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.packages.RuleClass.Builder;
+import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
+import com.google.devtools.build.lib.rules.java.J2ObjcConfiguration;
+import com.google.devtools.build.lib.rules.java.JavaCompilationArgsProvider;
+import com.google.devtools.build.lib.rules.java.JavaConfiguration;
 import com.google.devtools.build.lib.rules.java.JavaSourceInfoProvider;
 
 /**
@@ -35,6 +39,8 @@ public final class BazelJavaLibraryRule implements RuleDefinition {
   public RuleClass build(Builder builder, final RuleDefinitionEnvironment env) {
 
     return builder
+        .requiresConfigurationFragments(
+            JavaConfiguration.class, CppConfiguration.class, J2ObjcConfiguration.class)
         /* <!-- #BLAZE_RULE(java_library).IMPLICIT_OUTPUTS -->
         <ul>
           <li><code>lib<var>name</var>.jar</code>: A Java archive containing the class files.</li>
@@ -144,6 +150,7 @@ public final class BazelJavaLibraryRule implements RuleDefinition {
         .add(attr("exported_plugins", LABEL_LIST).cfg(HOST).allowedRuleClasses("java_plugin")
             .legacyAllowAnyFileType())
         .advertiseProvider(JavaSourceInfoProvider.class)
+        .advertiseProvider(JavaCompilationArgsProvider.class)
         .build();
   }
 
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcCommandLineOptions.java
new file mode 100644
index 0000000000..6c09c84dd7
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcCommandLineOptions.java
@@ -0,0 +1,50 @@
+// Copyright 2015 Google Inc. 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.
+
+package com.google.devtools.build.lib.rules.java;
+
+import com.google.common.collect.Multimap;
+import com.google.devtools.build.lib.analysis.config.FragmentOptions;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.common.options.Converters;
+import com.google.devtools.common.options.Option;
+
+import java.util.List;
+
+/**
+ * Command-line options for J2ObjC translation of Java source code to ObjC.
+ * These command line options are used by Java rules that can be transpiled
+ * (specifically, J2ObjCAspects thereof).
+ */
+public class J2ObjcCommandLineOptions extends FragmentOptions {
+  @Option(name = "j2objc_translation_flags",
+      converter = Converters.CommaSeparatedOptionListConverter.class,
+      allowMultiple = true,
+      defaultValue = "",
+      category = "flags",
+      help = "Additional options to pass to the J2ObjC tool."
+      )
+  public List<String> translationFlags;
+
+  @Option(name = "j2objc_dead_code_removal",
+      defaultValue = "false",
+      category = "undocumented",
+      help = "Whether to perform J2ObjC dead code removal to strip unused code from the final app "
+          + "bundle."
+      )
+  public boolean removeDeadCode;
+
+  @Override
+  public void addAllLabels(Multimap<String, Label> labelMap) {}
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcConfiguration.java
new file mode 100644
index 0000000000..9a24e446a0
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/J2ObjcConfiguration.java
@@ -0,0 +1,130 @@
+// Copyright 2015 Google Inc. 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.
+
+package com.google.devtools.build.lib.rules.java;
+
+import com.google.common.base.Joiner;
+import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
+import com.google.devtools.build.lib.analysis.config.BuildOptions;
+import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
+import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
+import com.google.devtools.build.lib.analysis.config.FragmentOptions;
+import com.google.devtools.build.lib.events.Event;
+import com.google.devtools.build.lib.events.EventHandler;
+
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * A J2ObjC transpiler configuration fragment containing J2ObjC translation flags.
+ * This configuration fragment is used by Java rules that can be transpiled
+ * (specifically, J2ObjCAspects thereof).
+ */
+public class J2ObjcConfiguration extends Fragment {
+  /**
+   * Always-on flags for J2ObjC translation. These flags will always be used for invoking the J2ObjC
+   * transpiler. See https://github.com/google/j2objc/wiki/j2objc for flag documentation.
+   */
+  private static final Set<String> J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS = ImmutableSet.of(
+      "-encoding",
+      "UTF-8",
+      "--doc-comments",
+      "--extract-unsequenced",
+      "--final-methods-as-functions",
+      "--hide-private-members",
+      "--segmented-headers",
+      "-XcombineJars");
+
+  /**
+   * Allowed flags for J2ObjC translation. See https://github.com/google/j2objc/wiki/j2objc for flag
+   * documentation.
+   */
+  static final Set<String> J2OBJC_BLACKLISTED_TRANSLATION_FLAGS =
+      ImmutableSet.of("--prefixes", "--prefix", "-x");
+
+  static final String INVALID_TRANSLATION_FLAGS_MSG_TEMPLATE =
+      "J2Objc translation flags: %s not supported. Unsupported flags are: %s";
+
+  /**
+   * Configuration loader for {@link J2ObjcConfiguration}.
+   */
+  public static class Loader implements ConfigurationFragmentFactory {
+    @Override
+    public Fragment create(ConfigurationEnvironment env, BuildOptions buildOptions) {
+      return new J2ObjcConfiguration(buildOptions.get(J2ObjcCommandLineOptions.class));
+    }
+
+    @Override
+    public Class<? extends Fragment> creates() {
+      return J2ObjcConfiguration.class;
+    }
+
+    @Override
+    public ImmutableSet<Class<? extends FragmentOptions>> requiredOptions() {
+      return ImmutableSet.<Class<? extends FragmentOptions>>of(J2ObjcCommandLineOptions.class);
+    }
+  }
+
+  private final Set<String> translationFlags;
+  private final boolean removeDeadCode;
+
+  J2ObjcConfiguration(J2ObjcCommandLineOptions j2ObjcOptions) {
+    this.removeDeadCode = j2ObjcOptions.removeDeadCode;
+    this.translationFlags = ImmutableSet.<String>builder()
+        .addAll(j2ObjcOptions.translationFlags)
+        .addAll(J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS)
+        .build();
+  }
+
+  /**
+   * Returns the translation flags used to invoke the J2ObjC transpiler. The returned flags contain
+   * both the always-on flags from {@link #J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS} and user-specified
+   * flags from {@link J2ObjcCommandLineOptions}. The set of valid flags can be found at
+   * {@link #J2OBJC_BLACKLISTED_TRANSLATION_FLAGS}.
+   */
+  public Iterable<String> getTranslationFlags() {
+    return translationFlags;
+  }
+
+  /**
+   * Returns whether to perform J2ObjC dead code removal. If true, the list of entry classes will be
+   * collected transitively throuh "entry_classes" attribute on j2objc_library and used as entry
+   * points to perform dead code analysis. Unused classes will then be removed from the final ObjC
+   * app bundle.
+   */
+  public boolean removeDeadCode() {
+    return removeDeadCode;
+  }
+
+  @Override
+  public String getName() {
+    return "J2ObjC";
+  }
+
+  @Override
+  public String cacheKey() {
+    return Joiner.on(" ").join(translationFlags) + "-" + String.valueOf(removeDeadCode);
+  }
+
+  @Override
+  public void reportInvalidOptions(EventHandler reporter, BuildOptions buildOptions) {
+    if (!Collections.disjoint(translationFlags, J2OBJC_BLACKLISTED_TRANSLATION_FLAGS)) {
+      String errorMsg = String.format(INVALID_TRANSLATION_FLAGS_MSG_TEMPLATE,
+          Joiner.on(",").join(translationFlags),
+          Joiner.on(",").join(J2OBJC_BLACKLISTED_TRANSLATION_FLAGS));
+      reporter.handle(Event.error(errorMsg));
+    }
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/java/JavaImportBaseRule.java b/src/main/java/com/google/devtools/build/lib/rules/java/JavaImportBaseRule.java
index 8db95eb81e..dc195c78ae 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/java/JavaImportBaseRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/java/JavaImportBaseRule.java
@@ -27,6 +27,7 @@ import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
 import com.google.devtools.build.lib.packages.RuleClass;
 import com.google.devtools.build.lib.packages.RuleClass.Builder;
 import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
+import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 
 /**
  * A base rule for building the java_import rule.
@@ -36,6 +37,8 @@ public class JavaImportBaseRule implements RuleDefinition {
   @Override
   public RuleClass build(Builder builder, RuleDefinitionEnvironment environment) {
     return builder
+        .requiresConfigurationFragments(JavaConfiguration.class, CppConfiguration.class,
+            J2ObjcConfiguration.class)
         .add(attr(":host_jdk", LABEL)
             .cfg(HOST)
             .value(JavaSemantics.HOST_JDK))
@@ -71,6 +74,7 @@ public class JavaImportBaseRule implements RuleDefinition {
         .add(attr("constraints", STRING_LIST)
             .orderIndependent()
             .nonconfigurable("used in Attribute.validityPredicate implementations (loading time)"))
+        .advertiseProvider(JavaSourceInfoProvider.class)
         .advertiseProvider(JavaCompilationArgsProvider.class)
         .build();
   }
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/BazelJ2ObjcLibraryRule.java b/src/main/java/com/google/devtools/build/lib/rules/objc/BazelJ2ObjcLibraryRule.java
new file mode 100644
index 0000000000..a976b688a4
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/BazelJ2ObjcLibraryRule.java
@@ -0,0 +1,55 @@
+// Copyright 2015 Google Inc. 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.
+
+package com.google.devtools.build.lib.rules.objc;
+
+import static com.google.devtools.build.lib.packages.Attribute.attr;
+import static com.google.devtools.build.lib.packages.Type.LABEL_LIST;
+
+import com.google.devtools.build.lib.analysis.RuleDefinition;
+import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
+import com.google.devtools.build.lib.packages.RuleClass;
+import com.google.devtools.build.lib.packages.RuleClass.Builder;
+
+/**
+ * Concrete implementation of J2ObjCLibraryBaseRule.
+ */
+public class BazelJ2ObjcLibraryRule implements RuleDefinition {
+
+  @Override
+  public RuleClass build(Builder builder, RuleDefinitionEnvironment env) {
+    return builder
+          /* <!-- #BLAZE_RULE(j2objc_library).ATTRIBUTE(deps) -->
+          A list of <code>j2objc_library</code>, <code>java_library</code>
+          and <code>java_import</code> targets that contain
+          Java files to be transpiled to Objective-C.
+          ${SYNOPSIS}
+          <!-- #END_BLAZE_RULE.ATTRIBUTE -->*/
+        .add(attr("deps", LABEL_LIST)
+            .aspect(J2ObjcAspect.class)
+            .direct_compile_time_input()
+            .allowedRuleClasses("j2objc_library", "java_library", "java_import")
+            .allowedFileTypes())
+        .build();
+  }
+
+  @Override
+  public Metadata getMetadata() {
+    return RuleDefinition.Metadata.builder()
+        .name("j2objc_library")
+        .factoryClass(J2ObjcLibrary.class)
+        .ancestors(J2ObjcLibraryBaseRule.class)
+        .build();
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
index 4a7bb7f401..1f346ed7a7 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/CompilationSupport.java
@@ -56,6 +56,7 @@ import com.google.devtools.build.lib.analysis.config.CompilationMode;
 import com.google.devtools.build.lib.collect.nestedset.NestedSet;
 import com.google.devtools.build.lib.packages.TargetUtils;
 import com.google.devtools.build.lib.rules.cpp.LinkerInputs;
+import com.google.devtools.build.lib.rules.java.J2ObjcConfiguration;
 import com.google.devtools.build.lib.rules.objc.ObjcCommon.CompilationAttributes;
 import com.google.devtools.build.lib.rules.objc.XcodeProvider.Builder;
 import com.google.devtools.build.lib.shell.ShellUtils;
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcAspect.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcAspect.java
new file mode 100644
index 0000000000..99bdfb4e22
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcAspect.java
@@ -0,0 +1,282 @@
+// Copyright 2015 Google Inc. 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.
+
+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 com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.Aspect;
+import com.google.devtools.build.lib.analysis.ConfiguredAspectFactory;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.TransitiveInfoCollection;
+import com.google.devtools.build.lib.analysis.actions.CustomCommandLine;
+import com.google.devtools.build.lib.analysis.actions.SpawnAction;
+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.AspectDefinition;
+import com.google.devtools.build.lib.packages.Type;
+import com.google.devtools.build.lib.rules.java.J2ObjcConfiguration;
+import com.google.devtools.build.lib.rules.java.JavaCompilationArgsProvider;
+import com.google.devtools.build.lib.rules.java.JavaCompilationHelper;
+import com.google.devtools.build.lib.rules.java.JavaSourceInfoProvider;
+import com.google.devtools.build.lib.rules.java.Jvm;
+import com.google.devtools.build.lib.rules.objc.J2ObjcSource.SourceType;
+import com.google.devtools.build.lib.syntax.Label;
+import com.google.devtools.build.lib.syntax.Label.SyntaxException;
+import com.google.devtools.build.lib.util.FileType;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+import java.util.List;
+
+/**
+ * J2ObjC transpilation aspect for Java rules.
+ */
+public class J2ObjcAspect implements ConfiguredAspectFactory {
+  /**
+   * Adds the attribute aspect args to the given AspectDefinition.Builder.
+   */
+  protected AspectDefinition.Builder addAttributeAspects(AspectDefinition.Builder builder) {
+    return builder.attributeAspect("deps", J2ObjcAspect.class)
+        .attributeAspect("exports", J2ObjcAspect.class)
+        .attributeAspect("runtime_deps", J2ObjcAspect.class);
+  }
+
+  @Override
+  public AspectDefinition getDefinition() {
+    return addAttributeAspects(new AspectDefinition.Builder("J2ObjCAspect"))
+        .requireProvider(JavaSourceInfoProvider.class)
+        .requireProvider(JavaCompilationArgsProvider.class)
+        .add(attr("$j2objc", LABEL).cfg(HOST).exec()
+            .value(parseLabel("//tools/j2objc:j2objc_deploy.jar")))
+        .add(attr("$j2objc_wrapper", LABEL)
+            .allowedFileTypes(FileType.of(".py"))
+            .cfg(HOST)
+            .exec()
+            .singleArtifact()
+            .value(parseLabel("//tools/j2objc:j2objc_wrapper")))
+        .build();
+  }
+
+  private static Label parseLabel(String from) {
+    try {
+      return Label.parseAbsolute(from);
+    } catch (SyntaxException e) {
+      throw new IllegalArgumentException(from);
+    }
+  }
+
+  @Override
+  public Aspect create(ConfiguredTarget base, RuleContext ruleContext) {
+    Aspect.Builder builder = new Aspect.Builder();
+
+    JavaCompilationArgsProvider compilationArgsProvider =
+        base.getProvider(JavaCompilationArgsProvider.class);
+    JavaSourceInfoProvider sourceInfoProvider =
+        base.getProvider(JavaSourceInfoProvider.class);
+
+    ImmutableSet<Artifact> javaInputFiles = ImmutableSet.<Artifact>builder()
+        .addAll(sourceInfoProvider.getSourceFiles())
+        .addAll(sourceInfoProvider.getSourceJars())
+        .addAll(sourceInfoProvider.getSourceJarsForJarFiles())
+        .build();
+
+    NestedSetBuilder<Artifact> depsHeaderMappingsBuilder = NestedSetBuilder.stableOrder();
+    NestedSetBuilder<Artifact> depsClassMappingsBuilder = NestedSetBuilder.stableOrder();
+    NestedSetBuilder<Artifact> depsDependencyMappingsBuilder = NestedSetBuilder.stableOrder();
+
+    for (J2ObjcMappingFileProvider provider : getJ2ObjCMappings(ruleContext)) {
+      depsHeaderMappingsBuilder.addTransitive(provider.getHeaderMappingFiles());
+      depsClassMappingsBuilder.addTransitive(provider.getClassMappingFiles());
+      depsDependencyMappingsBuilder.addTransitive(provider.getDependencyMappingFiles());
+    }
+
+    NestedSet<Artifact> depsHeaderMappings = depsHeaderMappingsBuilder.build();
+    NestedSet<Artifact> depsClassMappings = depsClassMappingsBuilder.build();
+    NestedSet<Artifact> depsDependencyMappings = depsDependencyMappingsBuilder.build();
+
+    J2ObjcSrcsProvider.Builder srcsBuilder = new J2ObjcSrcsProvider.Builder();
+    J2ObjcMappingFileProvider j2ObjcMappingFileProvider;
+
+    if (!javaInputFiles.isEmpty()) {
+      J2ObjcSource j2ObjcSource = buildJ2ObjcSource(ruleContext, javaInputFiles);
+
+      createJ2ObjcTranspilationAction(ruleContext, depsHeaderMappings, depsClassMappings,
+          javaInputFiles, compilationArgsProvider, j2ObjcSource);
+
+      // J2ObjC merges all input header mapping files into the output header mapping file, so we
+      // only need to export the output header mapping file here.
+      NestedSet<Artifact> headerMappingFiles = NestedSetBuilder.<Artifact>stableOrder()
+          .add(j2ObjcOutputHeaderMappingFile(ruleContext))
+          .build();
+      NestedSet<Artifact> dependencyMappingFiles = NestedSetBuilder.<Artifact>stableOrder()
+          .add(j2ObjcOutputDependencyMappingFile(ruleContext))
+          .addTransitive(depsDependencyMappings)
+          .build();
+
+      srcsBuilder.addSource(j2ObjcSource);
+      j2ObjcMappingFileProvider = new J2ObjcMappingFileProvider(
+          headerMappingFiles, depsClassMappings, dependencyMappingFiles);
+    } else {
+      j2ObjcMappingFileProvider = new J2ObjcMappingFileProvider(
+          depsHeaderMappings, depsClassMappings, depsDependencyMappings);
+    }
+
+    for (J2ObjcSrcsProvider provider :
+        ruleContext.getPrerequisites("exports", Mode.TARGET, J2ObjcSrcsProvider.class)) {
+      srcsBuilder.addTransitive(provider);
+    }
+
+    srcsBuilder.addTransitiveFromDeps(ruleContext);
+
+    return builder
+        .addProvider(J2ObjcSrcsProvider.class, srcsBuilder.build())
+        .addProvider(J2ObjcMappingFileProvider.class, j2ObjcMappingFileProvider)
+        .build();
+  }
+
+  private static void createJ2ObjcTranspilationAction(
+      RuleContext ruleContext,
+      NestedSet<Artifact> depsHeaderMappingFiles,
+      NestedSet<Artifact> depsClassMappingFiles,
+      Iterable<Artifact> sources,
+      JavaCompilationArgsProvider compArgsProvider,
+      J2ObjcSource j2ObjcSource) {
+    CustomCommandLine.Builder argBuilder = CustomCommandLine.builder();
+    PathFragment javaExecutable = ruleContext.getHostConfiguration().getFragment(Jvm.class)
+        .getJavaExecutable();
+    argBuilder.add("--java").add(javaExecutable.getPathString());
+
+    Artifact j2ObjcDeployJar = ruleContext.getPrerequisiteArtifact("$j2objc", Mode.HOST);
+    argBuilder.addExecPath("--j2objc", j2ObjcDeployJar);
+
+    argBuilder.add("--main_class").add("com.google.devtools.j2objc.J2ObjC");
+    argBuilder.addJoinExecPaths("--translated_source_files", ",", j2ObjcSource.getObjcSrcs());
+    argBuilder.add("--objc_file_path").addPath(j2ObjcSource.getObjcFilePath());
+
+    Artifact outputDependencyMappingFile = j2ObjcOutputDependencyMappingFile(ruleContext);
+    argBuilder.addExecPath("--output_dependency_mapping_file", outputDependencyMappingFile);
+
+    Iterable<String> translationFlags = ruleContext
+        .getFragment(J2ObjcConfiguration.class)
+        .getTranslationFlags();
+    argBuilder.add(translationFlags);
+
+    if (!depsHeaderMappingFiles.isEmpty()) {
+      argBuilder.addJoinExecPaths("--header-mapping", ",", depsHeaderMappingFiles);
+    }
+
+    Artifact outputHeaderMappingFile = j2ObjcOutputHeaderMappingFile(ruleContext);
+    argBuilder.addExecPath("--output-header-mapping", outputHeaderMappingFile);
+
+    if (!depsClassMappingFiles.isEmpty()) {
+      argBuilder.addJoinExecPaths("--mapping", ",", depsClassMappingFiles);
+    }
+
+    argBuilder.add("-d").addPath(j2ObjcSource.getObjcFilePath());
+
+    // In J2ObjC, the jars you pass as dependencies must be precisely the same as the
+    // jars used to transpile those dependencies--we cannot use ijars here.
+    NestedSet<Artifact> compileTimeJars =
+        compArgsProvider.getRecursiveJavaCompilationArgs().getRuntimeJars();
+    if (!compileTimeJars.isEmpty()) {
+      argBuilder.addJoinExecPaths("-classpath", ":", compileTimeJars);
+    }
+
+    argBuilder.addExecPaths(sources);
+
+    SpawnAction.Builder builder = new SpawnAction.Builder()
+        .setMnemonic("TranspilingJ2objc")
+        .setExecutable(ruleContext.getPrerequisiteArtifact("$j2objc_wrapper", Mode.HOST))
+        .addInput(ruleContext.getPrerequisiteArtifact("$j2objc_wrapper", Mode.HOST))
+        .addInput(j2ObjcDeployJar)
+        .addInputs(sources)
+        .addTransitiveInputs(compileTimeJars)
+        .addInputs(JavaCompilationHelper.getHostJavabaseInputs(ruleContext))
+        .addTransitiveInputs(depsHeaderMappingFiles)
+        .addTransitiveInputs(depsClassMappingFiles)
+        .setCommandLine(argBuilder.build())
+        .addOutputs(j2ObjcSource.getObjcSrcs())
+        .addOutputs(j2ObjcSource.getObjcHdrs())
+        .addOutput(outputHeaderMappingFile)
+        .addOutput(outputDependencyMappingFile);
+
+    ruleContext.registerAction(builder.build(ruleContext));
+  }
+
+  private static List<? extends J2ObjcMappingFileProvider> getJ2ObjCMappings(RuleContext context) {
+    ImmutableList.Builder<J2ObjcMappingFileProvider> mappingFileProviderBuilder =
+        new ImmutableList.Builder<>();
+    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "deps");
+    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "runtime_deps");
+    addJ2ObjCMappingsForAttribute(mappingFileProviderBuilder, context, "exports");
+    return mappingFileProviderBuilder.build();
+  }
+
+  private static void addJ2ObjCMappingsForAttribute(
+      ImmutableList.Builder<J2ObjcMappingFileProvider> builder, RuleContext context,
+      String attributeName) {
+    if (context.attributes().has(attributeName, Type.LABEL_LIST)) {
+      for (TransitiveInfoCollection dependencyInfoDatum :
+          context.getPrerequisites(attributeName, Mode.TARGET)) {
+        J2ObjcMappingFileProvider provider =
+            dependencyInfoDatum.getProvider(J2ObjcMappingFileProvider.class);
+        if (provider != null) {
+          builder.add(provider);
+        }
+      }
+    }
+  }
+
+  private static Artifact j2ObjcOutputHeaderMappingFile(RuleContext ruleContext) {
+    return ObjcRuleClasses.artifactByAppendingToBaseName(ruleContext, ".mapping.j2objc");
+  }
+
+  private static Artifact j2ObjcOutputDependencyMappingFile(RuleContext ruleContext) {
+    return ObjcRuleClasses.artifactByAppendingToBaseName(ruleContext, ".dependency_mapping.j2objc");
+  }
+
+  private J2ObjcSource buildJ2ObjcSource(RuleContext ruleContext,
+      Iterable<Artifact> javaInputSourceFiles) {
+    PathFragment objcFileRootRelativePath = ruleContext.getUniqueDirectory("_j2objc");
+    PathFragment objcFilePath = ruleContext
+        .getConfiguration()
+        .getBinFragment()
+        .getRelative(objcFileRootRelativePath);
+    Iterable<Artifact> objcSrcs = getOutputObjcFiles(ruleContext, javaInputSourceFiles,
+        objcFileRootRelativePath, ".m");
+    Iterable<Artifact> objcHdrs = getOutputObjcFiles(ruleContext, javaInputSourceFiles,
+        objcFileRootRelativePath, ".h");
+    return new J2ObjcSource(ruleContext.getRule().getLabel(), objcSrcs, objcHdrs, objcFilePath,
+        SourceType.JAVA);
+  }
+
+  private Iterable<Artifact> getOutputObjcFiles(RuleContext ruleContext,
+      Iterable<Artifact> javaSrcs, PathFragment objcFileRootRelativePath, String suffix) {
+    ImmutableList.Builder<Artifact> objcSources = ImmutableList.builder();
+
+    for (Artifact javaSrc : javaSrcs) {
+      objcSources.add(ruleContext.getRelatedArtifact(
+          objcFileRootRelativePath.getRelative(javaSrc.getExecPath()), suffix));
+    }
+
+    return objcSources.build();
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
deleted file mode 100644
index 7d1f88b4d4..0000000000
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcCommandLineOptions.java
+++ /dev/null
@@ -1,48 +0,0 @@
-// Copyright 2015 Google Inc. 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.
-
-package com.google.devtools.build.lib.rules.objc;
-
-import com.google.common.collect.Multimap;
-import com.google.devtools.build.lib.analysis.config.FragmentOptions;
-import com.google.devtools.build.lib.syntax.Label;
-import com.google.devtools.common.options.Converters;
-import com.google.devtools.common.options.Option;
-
-import java.util.List;
-
-/**
- * Command-line Options for J2ObjC translation of Java source code to ObjC.
- */
-public class J2ObjcCommandLineOptions extends FragmentOptions {
-  @Option(name = "j2objc_translation_flags",
-      converter = Converters.CommaSeparatedOptionListConverter.class,
-      allowMultiple = true,
-      defaultValue = "",
-      category = "undocumented",
-      help = "Specifies the translation flags for the J2ObjC transpiler."
-      )
-  public List<String> translationFlags;
-
-  @Option(name = "j2objc_dead_code_removal",
-      defaultValue = "false",
-      category = "undocumented",
-      help = "Whether to perform J2ObjC dead code removal to strip unused code from the final app "
-          + "bundle."
-      )
-  public boolean removeDeadCode;
-
-  @Override
-  public void addAllLabels(Multimap<String, Label> labelMap) {}
-}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcConfiguration.java
deleted file mode 100644
index afb3038169..0000000000
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcConfiguration.java
+++ /dev/null
@@ -1,128 +0,0 @@
-// Copyright 2015 Google Inc. 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.
-
-package com.google.devtools.build.lib.rules.objc;
-
-import com.google.common.base.Joiner;
-import com.google.common.collect.ImmutableSet;
-import com.google.devtools.build.lib.analysis.config.BuildConfiguration.Fragment;
-import com.google.devtools.build.lib.analysis.config.BuildOptions;
-import com.google.devtools.build.lib.analysis.config.ConfigurationEnvironment;
-import com.google.devtools.build.lib.analysis.config.ConfigurationFragmentFactory;
-import com.google.devtools.build.lib.analysis.config.FragmentOptions;
-import com.google.devtools.build.lib.events.Event;
-import com.google.devtools.build.lib.events.EventHandler;
-
-import java.util.Collections;
-import java.util.Set;
-
-/**
- * A J2ObjC transpiler configuration containing J2ObjC translation flags.
- */
-public class J2ObjcConfiguration extends Fragment {
-  /**
-   * Always-on flags for J2ObjC translation. These flags will always be used for invoking the J2ObjC
-   * transpiler. See https://github.com/google/j2objc/wiki/j2objc for flag documentation.
-   */
-  private static final Set<String> J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS = ImmutableSet.of(
-      "-encoding",
-      "UTF-8",
-      "--doc-comments",
-      "--extract-unsequenced",
-      "--final-methods-as-functions",
-      "--hide-private-members",
-      "--segmented-headers",
-      "-XcombineJars");
-
-  /**
-   * Allowed flags for J2ObjC translation. See https://github.com/google/j2objc/wiki/j2objc for flag
-   * documentation.
-   */
-  static final Set<String> J2OBJC_BLACKLISTED_TRANSLATION_FLAGS =
-      ImmutableSet.of("--prefixes", "--prefix", "-x");
-
-  static final String INVALID_TRANSLATION_FLAGS_MSG_TEMPLATE =
-      "J2Objc translation flags: %s not supported. Unsupported flags are: %s";
-
-  /**
-   * Configuration loader for {@link J2ObjcConfiguration}.
-   */
-  public static class Loader implements ConfigurationFragmentFactory {
-    @Override
-    public Fragment create(ConfigurationEnvironment env, BuildOptions buildOptions) {
-      return new J2ObjcConfiguration(buildOptions.get(J2ObjcCommandLineOptions.class));
-    }
-
-    @Override
-    public Class<? extends Fragment> creates() {
-      return J2ObjcConfiguration.class;
-    }
-
-    @Override
-    public ImmutableSet<Class<? extends FragmentOptions>> requiredOptions() {
-      return ImmutableSet.<Class<? extends FragmentOptions>>of(J2ObjcCommandLineOptions.class);
-    }
-  }
-
-  private final Set<String> translationFlags;
-  private final boolean removeDeadCode;
-
-  J2ObjcConfiguration(J2ObjcCommandLineOptions j2ObjcOptions) {
-    this.removeDeadCode = j2ObjcOptions.removeDeadCode;
-    this.translationFlags = ImmutableSet.<String>builder()
-        .addAll(j2ObjcOptions.translationFlags)
-        .addAll(J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS)
-        .build();
-  }
-
-  /**
-   * Returns the translation flags used to invoke the J2ObjC transpiler. The returned flags contain
-   * both the always-on flags from {@link #J2OBJC_ALWAYS_ON_TRANSLATION_FLAGS} and user-specified
-   * flags from {@link J2ObjcCommandLineOptions}. The set of valid flags can be found at
-   * {@link #J2OBJC_BLACKLISTED_TRANSLATION_FLAGS}.
-   */
-  public Iterable<String> getTranslationFlags() {
-    return translationFlags;
-  }
-
-  /**
-   * Returns whether to perform J2ObjC dead code removal. If true, the list of entry classes will be
-   * collected transitively throuh "entry_classes" attribute on j2objc_library and used as entry
-   * points to perform dead code analysis. Unused classes will then be removed from the final ObjC
-   * app bundle.
-   */
-  public boolean removeDeadCode() {
-    return removeDeadCode;
-  }
-
-  @Override
-  public String getName() {
-    return "J2ObjC";
-  }
-
-  @Override
-  public String cacheKey() {
-    return Joiner.on(" ").join(translationFlags) + "-" + String.valueOf(removeDeadCode);
-  }
-
-  @Override
-  public void reportInvalidOptions(EventHandler reporter, BuildOptions buildOptions) {
-    if (!Collections.disjoint(translationFlags, J2OBJC_BLACKLISTED_TRANSLATION_FLAGS)) {
-      String errorMsg = String.format(INVALID_TRANSLATION_FLAGS_MSG_TEMPLATE,
-          Joiner.on(",").join(translationFlags),
-          Joiner.on(",").join(J2OBJC_BLACKLISTED_TRANSLATION_FLAGS));
-      reporter.handle(Event.error(errorMsg));
-    }
-  }
-}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibrary.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibrary.java
new file mode 100644
index 0000000000..e2224a8378
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibrary.java
@@ -0,0 +1,110 @@
+// Copyright 2015 Google Inc. 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.
+
+package com.google.devtools.build.lib.rules.objc;
+
+import static com.google.devtools.build.lib.collect.nestedset.Order.STABLE_ORDER;
+
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.ConfiguredTarget;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTargetBuilder;
+import com.google.devtools.build.lib.analysis.RuleContext;
+import com.google.devtools.build.lib.analysis.RunfilesProvider;
+import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
+import com.google.devtools.build.lib.packages.Type;
+import com.google.devtools.build.lib.rules.RuleConfiguredTargetFactory;
+import com.google.devtools.build.lib.rules.java.J2ObjcConfiguration;
+import com.google.devtools.build.lib.vfs.PathFragment;
+
+import java.util.List;
+
+/**
+ * Implementation for the "j2objc_library" rule, which exports ObjC source files translated from
+ * Java source files in java_library rules to dependent objc_binary rules for compilation and
+ * linking into the final application bundle. See {@link J2ObjcLibraryBaseRule} for details.
+ */
+public class J2ObjcLibrary implements RuleConfiguredTargetFactory {
+
+  public static final String NO_ENTRY_CLASS_ERROR_MSG =
+      "Entry classes must be specified when flag --compilationMode=opt is on in order to"
+          + " perform J2ObjC dead code stripping.";
+
+  @Override
+  public ConfiguredTarget create(RuleContext ruleContext) throws InterruptedException {
+    checkAttributes(ruleContext);
+
+    if (ruleContext.hasErrors()) {
+      return null;
+    }
+
+    J2ObjcSrcsProvider j2ObjcSrcsProvider = new J2ObjcSrcsProvider.Builder()
+        .addTransitiveFromDeps(ruleContext)
+        .addEntryClasses(ruleContext.attributes().get("entry_classes", Type.STRING_LIST))
+        .build();
+
+    ObjcProvider.Builder objcProvider = new ObjcProvider.Builder()
+        .addTransitiveAndPropagate(ruleContext.getPrerequisite(
+            "$jre_emul_lib", Mode.TARGET, ObjcProvider.class))
+        .addTransitiveAndPropagate(ruleContext.getPrerequisites(
+            "deps", Mode.TARGET, ObjcProvider.class));
+
+    if (j2ObjcSrcsProvider.hasProtos()) {
+      if (ruleContext.attributes().has("$protobuf_lib", Type.LABEL)) {
+        objcProvider.addTransitiveAndPropagate(ruleContext.getPrerequisite(
+            "$protobuf_lib", Mode.TARGET, ObjcProvider.class));
+      } else {
+        // In theory no Bazel rule should ever provide protos, because they're not supported yet.
+        // If we reach here, it's a programming error, not a rule error.
+        throw new IllegalStateException(
+            "Found protos in the dependencies of rule " + ruleContext.getLabel() + ", "
+                + "but protos are not supported in Bazel.");
+      }
+    }
+
+    for (J2ObjcSource j2objcSource : j2ObjcSrcsProvider.getSrcs()) {
+      objcProvider.addAll(ObjcProvider.HEADER, j2objcSource.getObjcHdrs());
+      objcProvider.add(ObjcProvider.INCLUDE, j2objcSource.getObjcFilePath());
+      objcProvider.add(ObjcProvider.INCLUDE, new PathFragment(
+          j2objcSource.getObjcFilePath(),
+          ruleContext.getConfiguration().getGenfilesFragment()));
+    }
+
+    return new RuleConfiguredTargetBuilder(ruleContext)
+        .setFilesToBuild(NestedSetBuilder.<Artifact>emptySet(STABLE_ORDER))
+        .add(RunfilesProvider.class, RunfilesProvider.EMPTY)
+        .addProvider(J2ObjcSrcsProvider.class, j2ObjcSrcsProvider)
+        .addProvider(
+            J2ObjcMappingFileProvider.class, ObjcRuleClasses.j2ObjcMappingFileProvider(ruleContext))
+        .addProvider(ObjcProvider.class, objcProvider.build())
+        .build();
+  }
+
+  private static void checkAttributes(RuleContext ruleContext) {
+    checkAttributes(ruleContext, "deps");
+    checkAttributes(ruleContext, "exports");
+  }
+
+  private static void checkAttributes(RuleContext ruleContext, String attributeName) {
+    if (!ruleContext.attributes().has(attributeName, Type.LABEL_LIST)) {
+      return;
+    }
+
+    List<String> entryClasses = ruleContext.attributes().get("entry_classes", Type.STRING_LIST);
+    J2ObjcConfiguration j2objcConfiguration = ruleContext.getFragment(J2ObjcConfiguration.class);
+    if (j2objcConfiguration.removeDeadCode() && (entryClasses == null || entryClasses.isEmpty())) {
+      ruleContext.attributeError("entry_classes", NO_ENTRY_CLASS_ERROR_MSG);
+    }
+  }
+}
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryBaseRule.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryBaseRule.java
new file mode 100644
index 0000000000..5842402ad0
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryBaseRule.java
@@ -0,0 +1,79 @@
+// Copyright 2015 Google Inc. 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.
+
+package com.google.devtools.build.lib.rules.objc;
+
+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.STRING_LIST;
+
+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.packages.RuleClass;
+import com.google.devtools.build.lib.packages.RuleClass.Builder;
+import com.google.devtools.build.lib.packages.RuleClass.Builder.RuleClassType;
+
+/**
+ * Abstract rule definition for j2objc_library.
+ */
+public class J2ObjcLibraryBaseRule implements RuleDefinition {
+  @Override
+  public RuleClass build(Builder builder, RuleDefinitionEnvironment env) {
+    // TODO(rduan): Add support for package prefixes.
+    return builder
+          /* <!-- #BLAZE_RULE(j2objc_library).ATTRIBUTE(entry_classes) -->
+          The list of Java classes whose translated ObjC counterparts will be referenced directly
+          by user ObjC code. This attibute is required if flag <code>--j2objc_dead_code_removal
+          </code> is on. The Java classes should be specified in their canonical names as defined by
+          <a href="http://docs.oracle.com/javase/specs/jls/se8/html/jls-6.html#jls-6.7">the Java
+          Language Specification.</a>
+          ${SYNOPSIS}
+          When flag <code>--j2objc_dead_code_removal</code> is specified, the list of entry classes
+          will be collected transitively and used as entry points to perform dead code analysis.
+          Unused classes will then be removed from the final ObjC app bundle.
+          <!-- #END_BLAZE_RULE.ATTRIBUTE -->*/
+        .add(attr("entry_classes", STRING_LIST))
+        .add(attr("$jre_emul_jar", LABEL)
+            .value(env.getLabel("//third_party/java_src/j2objc/jre_emul:libjre_emul.jar")))
+        .add(attr("$jre_emul_lib", LABEL)
+            .value(env.getLabel("//third_party/java_src/j2objc/jre_emul:jre_emul_lib")))
+        .build();
+  }
+
+  @Override
+  public Metadata getMetadata() {
+    return RuleDefinition.Metadata.builder()
+        .name("$j2objc_library_base")
+        .type(RuleClassType.ABSTRACT)
+        .ancestors(BaseRuleClasses.BaseRule.class, ObjcRuleClasses.CoptsRule.class)
+        .build();
+  }
+}
+
+// TODO(mthvedt): Add support and examples for open-source users.
+/*<!-- #BLAZE_RULE (NAME = j2objc_library, TYPE = LIBRARY, FAMILY = Objective-C) -->
+
+${ATTRIBUTE_SIGNATURE}
+
+<p>This rule uses <a href="https://github.com/google/j2objc">J2ObjC</a>
+to translate Java source files to Objective-C, which then can be used used as dependencies of
+<code>objc_library</code> and <code>objc_binary</code> rules. More information about J2ObjC
+can be found <a href="http://j2objc.org">here</a>.
+</p>
+
+
+${ATTRIBUTE_DEFINITION}
+
+<!-- #END_BLAZE_RULE -->*/
-- 
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