+    # Compute jar -> target.
+    self.context.log.debug('Mapping jars...')
+    compile_classpath = self.context.products.get_data('compile_classpath')
+    for jar_lib in self.context.targets(lambda t: isinstance(t, JarLibrary)):
+      for _, artifact_path in compile_classpath.get_for_target(jar_lib, transitive=False):
+        if artifact_path.endswith('.jar'):
+          for cls in self._jar_classfiles(artifact_path):
+            targets_by_file[cls].add(jar_lib)