Added an implicit output target to j2objc_library

This implicit output is similar to objc_library's fully linked static library. For j2objc_library targets, we can use this output to trigger transpilation and generate a fully linked static library.

PiperOrigin-RevId: 157062831

2 files changed, 69 insertions, 2 deletions

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
index 2b14cca296..37913f0e8a 100644
--- 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
@@ -19,6 +19,7 @@ import static com.google.devtools.build.lib.rules.objc.ObjcProvider.JRE_LIBRARY;
 import static com.google.devtools.build.lib.rules.objc.ObjcProvider.LIBRARY;
 import static com.google.devtools.build.lib.rules.objc.XcodeProductType.LIBRARY_STATIC;
 
+import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
 import com.google.devtools.build.lib.actions.Artifact;
 import com.google.devtools.build.lib.analysis.ConfiguredTarget;
@@ -48,6 +49,17 @@ public class J2ObjcLibrary implements RuleConfiguredTargetFactory {
   public static final ImmutableList<String> J2OBJC_SUPPORTED_RULES =
       ImmutableList.of("java_import", "java_library", "proto_library");
 
+  private ObjcCommon common(RuleContext ruleContext) {
+    return new ObjcCommon.Builder(ruleContext)
+        .setCompilationAttributes(
+            CompilationAttributes.Builder.fromRuleContext(ruleContext).build())
+        .addDeps(ruleContext.getPrerequisites("deps", Mode.TARGET))
+        .addDeps(ruleContext.getPrerequisites("jre_deps", Mode.TARGET))
+        .setIntermediateArtifacts(ObjcRuleClasses.intermediateArtifacts(ruleContext))
+        .setHasModuleMap()
+        .build();
+  }
+
   @Override
   public ConfiguredTarget create(RuleContext ruleContext)
       throws InterruptedException, RuleErrorException {
@@ -85,6 +97,23 @@ public class J2ObjcLibrary implements RuleConfiguredTargetFactory {
     J2ObjcMappingFileProvider j2ObjcMappingFileProvider = J2ObjcMappingFileProvider.union(
         ruleContext.getPrerequisites("deps", Mode.TARGET, J2ObjcMappingFileProvider.class));
 
+    ObjcCommon common = common(ruleContext);
+    CompilationArtifacts moduleMapCompilationArtifacts =
+        new CompilationArtifacts.Builder()
+            .setIntermediateArtifacts(ObjcRuleClasses.intermediateArtifacts(ruleContext))
+            .setPchFile(Optional.<Artifact>absent())
+            .build();
+
+    new CompilationSupport.Builder()
+        .setRuleContext(ruleContext)
+        .setIntermediateArtifacts(ObjcRuleClasses.intermediateArtifacts(ruleContext))
+        .build()
+        .registerFullyLinkAction(
+            common.getObjcProvider(),
+            ruleContext.getImplicitOutputArtifact(CompilationSupport.FULLY_LINKED_LIB))
+        .registerGenerateModuleMapAction(moduleMapCompilationArtifacts)
+        .validateAttributes();
+
     return new RuleConfiguredTargetBuilder(ruleContext)
         .setFilesToBuild(NestedSetBuilder.<Artifact>emptySet(STABLE_ORDER))
         .add(RunfilesProvider.class, RunfilesProvider.EMPTY)
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryRule.java b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryRule.java
index d2dcd3f087..19b46794bb 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryRule.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/J2ObjcLibraryRule.java
@@ -22,6 +22,7 @@ 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.rules.apple.AppleConfiguration;
+import com.google.devtools.build.lib.rules.cpp.CppConfiguration;
 
 /** <code>j2objc_library</code> rule declaration. */
 public class J2ObjcLibraryRule implements RuleDefinition {
@@ -35,7 +36,10 @@ public class J2ObjcLibraryRule implements RuleDefinition {
   public RuleClass build(Builder builder, RuleDefinitionEnvironment env) {
     return builder
         .requiresConfigurationFragments(
-            J2ObjcConfiguration.class, ObjcConfiguration.class, AppleConfiguration.class)
+            J2ObjcConfiguration.class,
+            ObjcConfiguration.class,
+            AppleConfiguration.class,
+            CppConfiguration.class)
         /* <!-- #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
@@ -71,6 +75,13 @@ public class J2ObjcLibraryRule implements RuleDefinition {
                 .direct_compile_time_input()
                 .allowedRuleClasses("j2objc_library", "java_library", "java_import")
                 .allowedFileTypes())
+        /*<!-- #BLAZE_RULE(j2objc_library).IMPLICIT_OUTPUTS -->
+        <ul>
+         <li><code><var>name</var>_fully_linked.a</code>: A fully linked static library that
+             contains the full transitive closure of transpiled dependencies.</li>
+        </ul>
+        <!-- #END_BLAZE_RULE.IMPLICIT_OUTPUTS -->*/
+        .setImplicitOutputsFunction(CompilationSupport.FULLY_LINKED_LIB)
         .cfg(AppleCrosstoolTransition.APPLE_CROSSTOOL_TRANSITION)
         .build();
   }
@@ -80,7 +91,34 @@ public class J2ObjcLibraryRule implements RuleDefinition {
     return RuleDefinition.Metadata.builder()
         .name("j2objc_library")
         .factoryClass(J2ObjcLibrary.class)
-        .ancestors(J2ObjcLibraryBaseRule.class)
+        .ancestors(
+            J2ObjcLibraryBaseRule.class,
+            ObjcRuleClasses.CrosstoolRule.class,
+            ObjcRuleClasses.LibtoolRule.class,
+            ObjcRuleClasses.XcrunRule.class)
         .build();
   }
 }
+
+/*<!-- #BLAZE_RULE (NAME = j2objc_library, TYPE = LIBRARY, FAMILY = Objective-C) -->
+
+<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 objc_library and objc_binary
+rules. Detailed information about J2ObjC itself can be found at  <a href="http://j2objc.org">the
+J2ObjC site</a>
+</p>
+<p>Custom J2ObjC transpilation flags can be specified using the build flag
+<code>--j2objc_translation_flags</code> in the command line.
+</p>
+<p>Please note that the translated files included in a j2objc_library target will be
+compiled using the default compilation configuration, the same configuration as for the sources of
+an objc_library rule with no compilation options specified in attributes.
+</p>
+<p>Plus, generated code is de-duplicated at target level, not source level. If you have two
+different Java targets that include the same Java source files, you may see a duplicate symbol error
+at link time. The correct way to resolve this issue is to move the shared Java source files into a
+separate common target that can be depended upon.
+</p>
+
+
+<!-- #END_BLAZE_RULE -->*/