Added enable_d8 to uses D8 instead of DX

D8 is the new default dexer in Android Studio. We're replacing DX with D8.
This improves the APK size by removing 30 KB.

Bug: 842681
Change-Id: Ic0d310f615d6aad44a55a2ab5f56ef40288df53f
Reviewed-on: https://chromium-review.googlesource.com/1079373
Commit-Queue: Tiger Oakes <tigero@google.com>
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565336}

DEPS

@@ -914,7 +914,7 @@ deps = {
       'packages': [
           {
               'package': 'chromium/third_party/r8',
-              'version': 'version:1.0.26',
+              'version': 'version:1.0.30',
           },
       ],
       'condition': 'checkout_android',

build/android/gyp/dex.py

@@ -8,8 +8,8 @@ import json
 import logging
 import optparse
 import os
+import shutil
 import sys
-import tempfile
 import zipfile
 
 from util import build_utils
@@ -17,7 +17,6 @@ from util import build_utils
 
 def _CheckFilePathEndsWithJar(parser, file_path):
   if not file_path.endswith(".jar"):
-    # dx ignores non .jar files.
     parser.error("%s does not end in .jar" % file_path)
 
 
@@ -43,8 +42,6 @@ def _ParseArgs(args):
   parser = optparse.OptionParser()
   build_utils.AddDepfileOption(parser)
 
-  parser.add_option('--android-sdk-tools',
-                    help='Android sdk build tools directory.')
   parser.add_option('--output-directory',
                     default=os.getcwd(),
                     help='Path to the output build directory.')
@@ -58,11 +55,6 @@ def _ParseArgs(args):
   parser.add_option('--proguard-enabled-input-path',
                     help=('Path to dex in Release mode when proguard '
                           'is enabled.'))
-  parser.add_option('--no-locals', default='0',
-                    help='Exclude locals list from the dex file.')
-  parser.add_option('--incremental',
-                    action='store_true',
-                    help='Enable incremental builds when possible.')
   parser.add_option('--inputs', help='A list of additional input paths.')
   parser.add_option('--excluded-paths',
                     help='A list of paths to exclude from the dex file.')
@@ -73,10 +65,12 @@ def _ParseArgs(args):
                     help='A JSON file containing multidex build configuration.')
   parser.add_option('--multi-dex', default=False, action='store_true',
                     help='Generate multiple dex files.')
+  parser.add_option('--d8-jar-path',
+                    help='Path to D8 jar.')
 
   options, paths = parser.parse_args(args)
 
-  required_options = ('android_sdk_tools',)
+  required_options = ('d8_jar_path',)
   build_utils.CheckOptions(options, parser, required=required_options)
 
   if options.multidex_configuration_path:
@@ -103,89 +97,45 @@ def _ParseArgs(args):
   return options, paths
 
 
-def _AllSubpathsAreClassFiles(paths, changes):
-  for path in paths:
-    if any(not p.endswith('.class') for p in changes.IterChangedSubpaths(path)):
-      return False
-  return True
+def _MoveTempDexFile(tmp_dex_dir, dex_path):
+  """Move the temp dex file out of |tmp_dex_dir|.
+
+  Args:
+    tmp_dex_dir: Path to temporary directory created with tempfile.mkdtemp().
+      The directory should have just a single file.
+    dex_path: Target path to move dex file to.
+
+  Raises:
+    Exception if there are multiple files in |tmp_dex_dir|.
+  """
+  tempfiles = os.listdir(tmp_dex_dir)
+  if len(tempfiles) > 1:
+    raise Exception('%d files created, expected 1' % len(tempfiles))
+
+  tmp_dex_path = os.path.join(tmp_dex_dir, tempfiles[0])
+  shutil.move(tmp_dex_path, dex_path)
 
 
-def _DexWasEmpty(paths, changes):
-  for path in paths:
-    if any(p.endswith('.class')
-           for p in changes.old_metadata.IterSubpaths(path)):
-      return False
+def _NoClassFiles(jar_paths):
+  """Returns True if there are no .class files in the given JARs.
+
+  Args:
+    jar_paths: list of strings representing JAR file paths.
+
+  Returns:
+    (bool) True if no .class files are found.
+  """
+  for jar_path in jar_paths:
+    with zipfile.ZipFile(jar_path) as jar:
+      if any(name.endswith('.class') for name in jar.namelist()):
+        return False
   return True
 
 
-def _IterAllClassFiles(changes):
-  for path in changes.IterAllPaths():
-    for subpath in changes.IterAllSubpaths(path):
-      if subpath.endswith('.class'):
-        yield path
-
-
-def _MightHitDxBug(changes):
-  # We've seen dx --incremental fail for small libraries. It's unlikely a
-  # speed-up anyways in this case.
-  num_classes = sum(1 for x in _IterAllClassFiles(changes))
-  if num_classes < 10:
-    return True
-
-  # We've also been able to consistently produce a failure by adding an empty
-  # line to the top of the first .java file of a library.
-  # https://crbug.com/617935
-  first_file = next(_IterAllClassFiles(changes))
-  for path in changes.IterChangedPaths():
-    for subpath in changes.IterChangedSubpaths(path):
-      if first_file == subpath:
-        return True
-  return False
-
-
-def _RunDx(changes, options, dex_cmd, paths):
-  with build_utils.TempDir() as classes_temp_dir:
-    # --multi-dex is incompatible with --incremental.
-    if options.multi_dex:
-      dex_cmd.append('--main-dex-list=%s' % options.main_dex_list_path)
-    else:
-      # --incremental tells dx to merge all newly dex'ed .class files with
-      # what that already exist in the output dex file (existing classes are
-      # replaced).
-      # Use --incremental when .class files are added or modified, but not when
-      # any are removed (since it won't know to remove them).
-      if (options.incremental
-          and not _MightHitDxBug(changes)
-          and changes.AddedOrModifiedOnly()):
-        changed_inputs = set(changes.IterChangedPaths())
-        changed_paths = [p for p in paths if p in changed_inputs]
-        if not changed_paths:
-          return
-        # When merging in other dex files, there's no easy way to know if
-        # classes were removed from them.
-        if (_AllSubpathsAreClassFiles(changed_paths, changes)
-            and not _DexWasEmpty(changed_paths, changes)):
-          dex_cmd.append('--incremental')
-          for path in changed_paths:
-            changed_subpaths = set(changes.IterChangedSubpaths(path))
-            # Note: |changed_subpaths| may be empty if nothing changed.
-            if changed_subpaths:
-              build_utils.ExtractAll(path, path=classes_temp_dir,
-                                     predicate=lambda p: p in changed_subpaths)
-          paths = [classes_temp_dir]
-
-    dex_cmd += paths
-    build_utils.CheckOutput(dex_cmd, print_stderr=False)
-
-  if options.dex_path.endswith('.zip'):
-    _RemoveUnwantedFilesFromZip(options.dex_path)
-
-
-def _OnStaleMd5(changes, options, dex_cmd, paths):
-  _RunDx(changes, options, dex_cmd, paths)
-  build_utils.WriteJson(
-      [os.path.relpath(p, options.output_directory) for p in paths],
-      options.dex_path + '.inputs')
+def _RunD8(dex_cmd, input_paths, output_path):
+  dex_cmd += ['--output', output_path]
+  dex_cmd += input_paths
+  build_utils.CheckOutput(dex_cmd, print_stderr=False)
 
 
 def main(args):
@@ -206,23 +156,8 @@ def main(args):
              os.path.relpath(p, options.output_directory) in exclude_paths]
 
   input_paths = list(paths)
-
-  dx_binary = os.path.join(options.android_sdk_tools, 'dx')
-  # See http://crbug.com/272064 for context on --force-jumbo.
-  # See https://github.com/android/platform_dalvik/commit/dd140a22d for
-  # --num-threads.
-  # See http://crbug.com/658782 for why -JXmx2G was added.
-  dex_cmd = [dx_binary, '-JXmx2G', '--num-threads=8', '--dex', '--force-jumbo',
-             '--output', options.dex_path]
-  if options.no_locals != '0':
-    dex_cmd.append('--no-locals')
-
   if options.multi_dex:
     input_paths.append(options.main_dex_list_path)
-    dex_cmd += [
-      '--multi-dex',
-      '--minimal-main-dex',
-    ]
 
   output_paths = [
     options.dex_path,
@@ -233,14 +168,40 @@ def main(args):
   # problems.
   force = int(os.environ.get('DISABLE_INCREMENTAL_DX', 0))
 
+  dex_cmd = ['java', '-jar', options.d8_jar_path]
+  if options.multi_dex:
+    dex_cmd += ['--main-dex-list', options.main_dex_list_path]
+
+  is_dex = options.dex_path.endswith('.dex')
+  is_jar = options.dex_path.endswith('.jar')
+
+  def on_stale_md5_callback():
+    if is_jar and _NoClassFiles(paths):
+      # Handle case where no classfiles are specified in inputs
+      # by creating an empty JAR
+      with zipfile.ZipFile(options.dex_path, 'w') as outfile:
+        outfile.comment = 'empty'
+    elif is_dex:
+      # .dex files can't specify a name for D8. Instead, we output them to a
+      # temp directory then move them after the command has finished running
+      # (see _MoveTempDexFile). For other files, tmp_dex_dir is None.
+      with build_utils.TempDir() as tmp_dex_dir:
+        _RunD8(dex_cmd, paths, tmp_dex_dir)
+        _MoveTempDexFile(tmp_dex_dir, options.dex_path)
+    else:
+      _RunD8(dex_cmd, paths, options.dex_path)
+
+    build_utils.WriteJson(
+        [os.path.relpath(p, options.output_directory) for p in paths],
+        options.dex_path + '.inputs')
+
   build_utils.CallAndWriteDepfileIfStale(
-      lambda changes: _OnStaleMd5(changes, options, dex_cmd, paths),
+      on_stale_md5_callback,
       options,
       input_paths=input_paths,
       input_strings=dex_cmd,
       output_paths=output_paths,
       force=force,
-      pass_changes=True,
       depfile_deps=input_paths)
 
 

build/config/android/internal_rules.gni

@@ -1112,21 +1112,10 @@ if (enable_java_templates) {
       args = [
         "--depfile",
         rebase_path(depfile, root_build_dir),
-        "--android-sdk-tools",
-        rebase_path(android_sdk_build_tools, root_build_dir),
         "--dex-path",
         _rebased_output,
       ]
 
-      if (enable_incremental_dx) {
-        args += [ "--incremental" ]
-      }
-
-      # EMMA requires --no-locals.
-      if (emma_coverage) {
-        args += [ "--no-locals=1" ]
-      }
-
       if (_enable_multidex) {
         args += [
           "--multi-dex",
@@ -1146,6 +1135,13 @@ if (enable_java_templates) {
         inputs += invoker.input_jars
         args += rebase_path(invoker.input_jars, root_build_dir)
       }
+
+      _d8_path = "//third_party/r8/lib/d8.jar"
+      inputs += [ _d8_path ]
+      args += [
+        "--d8-jar-path",
+        rebase_path(_d8_path, root_build_dir),
+      ]
     }
   }
 

third_party/r8/README.chromium

 Name: R8
 URL: https://r8.googlesource.com/r8
-Version: 1.0.26
+Version: 1.0.30
 License: BSD 3-Clause
 License File: NOT_SHIPPED
 Security Critical: no
@@ -8,7 +8,5 @@ Security Critical: no
 Description:
 D8 is a dexer that converts java byte code to dex code.
 It is contained in the R8 repo.
-We use a wrapper (compatdx) which lets D8 take the same arguments as DX,
-which it replaces.
 
 Local Modifications: None

third_party/r8/cipd.yaml

@@ -2,4 +2,4 @@ package: chromium/third_party/r8
 description: >
   D8 is a dexer that converts java byte code to dex code (part of the R8 repo).
 data:
-  - file: lib/compatdx.jar
+  - file: lib/d8.jar
\ No newline at end of file