Enable hashing of proxy natives when !is_java_debug

If is_java_debug is set to false the JNI generator and
JNI annotation processor will hash/obfuscate native method
declarations to save binary size.

Change-Id: Ic083a7fe6564665ed0ffa0a5e508b9d75697f6b3
Reviewed-on: https://chromium-review.googlesource.com/c/1318394
Commit-Queue: Aiden Benner <abenner@google.com>
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609366}

base/android/jni_generator/BUILD.gn

@@ -80,6 +80,14 @@ group("jni_generator_tests") {
   ]
 }
 
+java_cpp_template("processor_args_java") {
+  package_path = "org/chromium/jni_generator"
+  sources = [
+    "ProcessorArgs.template",
+  ]
+  defines = [ "IS_JAVA_DEBUG_VALUE=$is_java_debug" ]
+}
+
 java_annotation_processor("jni_processor") {
   java_files = [ "java/src/org/chromium/jni_generator/JniProcessor.java" ]
 
@@ -93,4 +101,6 @@ java_annotation_processor("jni_processor") {
     "//third_party/auto:auto_service_java",
     "//third_party/guava:guava_java",
   ]
+
+  srcjar_deps = [ ":processor_args_java" ]
 }

base/android/jni_generator/ProcessorArgs.template

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.jni_generator;
+
+class ProcessorArgs {
+    public static final boolean IS_JAVA_DEBUG = IS_JAVA_DEBUG_VALUE;
+}

base/android/jni_generator/java/src/org/chromium/jni_generator/JniProcessor.java

@@ -75,7 +75,7 @@ public class JniProcessor extends AbstractProcessor {
     private static MessageDigest sNativeMethodHashFunction;
 
     // If true, native methods in GEN_JNI will be named as a hash of their descriptor.
-    private static final boolean USE_HASH_FOR_METHODS = false;
+    private static final boolean USE_HASH_FOR_METHODS = !ProcessorArgs.IS_JAVA_DEBUG;
 
     // Limits the number characters of the Base64 encoded hash
     // of the method descriptor used as name of the generated

base/android/jni_generator/jni_registration_generator.py

@@ -10,6 +10,7 @@ RegisterNonMainDexNatives(). Together, these will use manual JNI registration
 to register all native methods that exist within an application."""
 
 import argparse
+import functools
 import multiprocessing
 import os
 import string
@@ -34,7 +35,11 @@ MERGEABLE_KEYS = [
 ]
 
 
-def _Generate(java_file_paths, srcjar_path, header_path=None, namespace=''):
+def _Generate(java_file_paths,
+              srcjar_path,
+              use_proxy_hash=False,
+              header_path=None,
+              namespace=''):
   """Generates files required to perform JNI registration.
 
   Generates a srcjar containing a single class, GEN_JNI, that contains all
@@ -53,34 +58,39 @@ def _Generate(java_file_paths, srcjar_path, header_path=None, namespace=''):
   # Without multiprocessing, script takes ~13 seconds for chrome_public_apk
   # on a z620. With multiprocessing, takes ~2 seconds.
   pool = multiprocessing.Pool()
-  results = [d for d in pool.imap_unordered(_DictForPath, java_file_paths) if d]
+
+  results = []
+  for d in pool.imap_unordered(
+      functools.partial(_DictForPath, use_proxy_hash=use_proxy_hash),
+      java_file_paths):
+    if d:
+      results.append(d)
   pool.close()
 
   # Sort to make output deterministic.
   results.sort(key=lambda d: d['FULL_CLASS_NAME'])
 
-  if header_path:
-    combined_dict = {}
-    for key in MERGEABLE_KEYS:
-      combined_dict[key] = ''.join(d.get(key, '') for d in results)
+  combined_dict = {}
+  for key in MERGEABLE_KEYS:
+    combined_dict[key] = ''.join(d.get(key, '') for d in results)
 
+  if header_path:
     combined_dict['HEADER_GUARD'] = \
         os.path.splitext(header_path)[0].replace('/', '_').upper() + '_'
     combined_dict['NAMESPACE'] = namespace
-
     header_content = CreateFromDict(combined_dict)
     with build_utils.AtomicOutput(header_path) as f:
       f.write(header_content)
 
   with build_utils.AtomicOutput(srcjar_path) as f:
     with zipfile.ZipFile(f, 'w') as srcjar:
-      # TODO(abenner): Write GEN_JNI.java here.
-      # build_utils.AddToZipHermetic(srcjar, 'org/chromium/base/GEN_JNI.java',
-      #     data='$CONTENT')
-      pass
+      build_utils.AddToZipHermetic(
+          srcjar,
+          'org/chromium/base/natives/GEN_JNI.java',
+          data=CreateProxyJavaFromDict(combined_dict))
 
 
-def _DictForPath(path):
+def _DictForPath(path, use_proxy_hash=False):
   with open(path) as f:
     contents = jni_generator.RemoveComments(f.read())
     if '@JniIgnoreNatives' in contents:
@@ -93,7 +103,8 @@ def _DictForPath(path):
   natives += jni_generator.NativeProxyHelpers.ExtractStaticProxyNatives(
       fully_qualified_class=fully_qualified_class,
       contents=contents,
-      ptr_type='long')
+      ptr_type='long',
+      use_hash=use_proxy_hash)
   if len(natives) == 0:
     return None
   namespace = jni_generator.ExtractJNINamespace(contents)
@@ -516,6 +527,11 @@ def main(argv):
                           default='',
                           help='Namespace to wrap the registration functions '
                           'into.')
+  arg_parser.add_argument(
+      '--use_proxy_hash',
+      action='store_true',
+      help='Enables hashing of the native declaration '
+      'for methods in an @JniNatives interface')
   args = arg_parser.parse_args(build_utils.ExpandFileArgs(argv[1:]))
   args.sources_files = build_utils.ParseGnList(args.sources_files)
 
@@ -529,6 +545,7 @@ def main(argv):
   _Generate(
       java_file_paths,
       args.srcjar_path,
+      use_proxy_hash=args.use_proxy_hash,
       header_path=args.header_path,
       namespace=args.namespace)
 

build/config/android/rules.gni

@@ -249,6 +249,10 @@ if (enable_java_templates) {
         rebase_path(_jni_generator_include, _jni_output_dir),
       ]
 
+      if (!is_java_debug) {
+        args += [ "--use_proxy_hash" ]
+      }
+
       if (enable_profiling) {
         args += [ "--enable_profiling" ]
       }
@@ -435,6 +439,17 @@ if (enable_java_templates) {
         "--depfile",
         rebase_path(depfile, root_build_dir),
       ]
+
+      if (!is_java_debug) {
+        args += [ "--use_proxy_hash" ]
+      }
+
+      if (defined(invoker.exception_files)) {
+        _rebase_exception_java_files =
+            rebase_path(invoker.exception_files, root_build_dir)
+        args += [ "--no_register_java=$_rebase_exception_java_files" ]
+      }
+
       if (defined(invoker.header_output)) {
         outputs += [ invoker.header_output ]
         args += [
@@ -442,11 +457,13 @@ if (enable_java_templates) {
           rebase_path(invoker.header_output, root_build_dir),
         ]
       }
+
       if (defined(invoker.sources_blacklist)) {
         _rebase_sources_blacklist =
             rebase_path(invoker.sources_blacklist, root_build_dir)
         args += [ "--sources-blacklist=$_rebase_sources_blacklist" ]
       }
+
       if (defined(invoker.namespace)) {
         args += [ "--namespace=${invoker.namespace}" ]
       }