Add gyp machinery to build with packed ARM relative relocations.

Add gypi and python files to support packing ARM relative relocations
during the build process.

Define a use_relocation_packer gyp variable to turn ARM relocation
packing on and off (currently set to 0).

BUG=385553

Review URL: https://codereview.chromium.org/358863002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@281286 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 224 insertions, 3 deletions

diff --git a/build/all.gyp b/build/all.gyp
index f2b3f5a..4f7b7cc 100644
--- a/build/all.gyp
+++ b/build/all.gyp
@@ -54,6 +54,7 @@
             '../chrome/chrome.gyp:chrome_shell_apk',
             '../remoting/remoting.gyp:remoting_apk',
             '../tools/telemetry/telemetry.gyp:*#host',
+            '../tools/relocation_packer/relocation_packer.gyp:relocation_packer_unittests#host',
             # TODO(nyquist) This should instead by a target for sync when all of
             # the sync-related code for Android has been upstreamed.
             # See http://crbug.com/159203
diff --git a/build/android/gyp/pack_arm_relocations.py b/build/android/gyp/pack_arm_relocations.py
new file mode 100755
index 0000000..9fbd977
--- /dev/null
+++ b/build/android/gyp/pack_arm_relocations.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+#
+# Copyright 2014 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.
+
+"""Pack ARM relative relocations in a library (or copy unchanged).
+
+If --enable-packing, invoke the relocation_packer tool to pack the .rel.dyn
+section in the given library files.  This step is inserted after the libraries
+are stripped.  Packing adds a new .android.rel.dyn section to the file and
+reduces the size of .rel.dyn accordingly.
+
+Currently packing only understands ARM32 shared libraries.  For all other
+architectures --enable-packing should be set to zero.  In this case the
+script copies files verbatim, with no attempt to pack relative relocations.
+
+Any library listed in --exclude-packing-list is also copied verbatim,
+irrespective of any --enable-packing setting.  Typically this would be
+'libchromium_android_linker.so'.
+"""
+
+import json
+import optparse
+import os
+import shlex
+import shutil
+import sys
+import tempfile
+
+from util import build_utils
+
+def PackArmLibraryRelocations(android_pack_relocations,
+                              android_objcopy,
+                              library_path,
+                              output_path):
+  if not build_utils.IsTimeStale(output_path, [library_path]):
+    return
+
+  # Copy and add a 'NULL' .android.rel.dyn section for the packing tool.
+  with tempfile.NamedTemporaryFile() as stream:
+    stream.write('NULL')
+    stream.flush()
+    objcopy_command = [android_objcopy,
+                       '--add-section', '.android.rel.dyn=%s' % stream.name,
+                       library_path, output_path]
+    build_utils.CheckOutput(objcopy_command)
+
+  # Pack R_ARM_RELATIVE relocations.
+  pack_command = [android_pack_relocations, output_path]
+  build_utils.CheckOutput(pack_command)
+
+
+def CopyArmLibraryUnchanged(library_path, output_path):
+  if not build_utils.IsTimeStale(output_path, [library_path]):
+    return
+
+  shutil.copy(library_path, output_path)
+
+
+def main():
+  parser = optparse.OptionParser()
+
+  parser.add_option('--enable-packing',
+      choices=['0', '1'],
+      help='Pack relocations if 1, otherwise plain file copy')
+  parser.add_option('--exclude-packing-list',
+      default='',
+      help='Names of any libraries explicitly not packed')
+  parser.add_option('--android-pack-relocations',
+      help='Path to the ARM relocations packer binary')
+  parser.add_option('--android-objcopy',
+      help='Path to the toolchain\'s objcopy binary')
+  parser.add_option('--stripped-libraries-dir',
+      help='Directory for stripped libraries')
+  parser.add_option('--packed-libraries-dir',
+      help='Directory for packed libraries')
+  parser.add_option('--libraries-file',
+      help='Path to json file containing list of libraries')
+  parser.add_option('--stamp', help='Path to touch on success')
+
+  options, _ = parser.parse_args()
+  enable_packing = options.enable_packing == '1'
+  exclude_packing_set = set(shlex.split(options.exclude_packing_list))
+
+  with open(options.libraries_file, 'r') as libfile:
+    libraries = json.load(libfile)
+
+  for library in libraries:
+    library_path = os.path.join(options.stripped_libraries_dir, library)
+    output_path = os.path.join(options.packed_libraries_dir, library)
+
+    if enable_packing and library not in exclude_packing_set:
+      PackArmLibraryRelocations(options.android_pack_relocations,
+                                options.android_objcopy,
+                                library_path,
+                                output_path)
+    else:
+      CopyArmLibraryUnchanged(library_path, output_path)
+
+  if options.stamp:
+    build_utils.Touch(options.stamp)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())
diff --git a/build/android/pack_arm_relocations.gypi b/build/android/pack_arm_relocations.gypi
new file mode 100644
index 0000000..5a6589b
--- /dev/null
+++ b/build/android/pack_arm_relocations.gypi
@@ -0,0 +1,76 @@
+# Copyright 2014 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.
+
+# This file is meant to be included into an action to provide a rule that
+# packs ARM relative relocations in native libraries.
+#
+# To use this, create a gyp target with the following form:
+#  {
+#    'action_name': 'pack_arm_relocations',
+#    'actions': [
+#      'variables': {
+#        'enable_packing': 'pack relocations if 1, plain file copy if 0'
+#        'exclude_packing_list': 'names of libraries explicitly not packed',
+#        'ordered_libraries_file': 'file generated by write_ordered_libraries'
+#        'input_paths': 'files to be added to the list of inputs'
+#        'stamp': 'file to touch when the action is complete'
+#        'stripped_libraries_dir': 'directory holding stripped libraries',
+#        'packed_libraries_dir': 'directory holding packed libraries',
+#      'includes': [ '../../build/android/pack_arm_relocations.gypi' ],
+#    ],
+#  },
+#
+
+{
+  'variables': {
+    'input_paths': [],
+  },
+  'inputs': [
+    '<(DEPTH)/build/android/gyp/util/build_utils.py',
+    '<(DEPTH)/build/android/gyp/pack_arm_relocations.py',
+    '<(ordered_libraries_file)',
+    '>@(input_paths)',
+  ],
+  'outputs': [
+    '<(stamp)',
+  ],
+  'conditions': [
+    ['enable_packing == 1', {
+      'message': 'Packing ARM relative relocations for <(_target_name)',
+      'dependencies': [
+        '<(DEPTH)/tools/relocation_packer/relocation_packer.gyp:relocation_packer#host',
+      ],
+      'inputs': [
+        '<(PRODUCT_DIR)/relocation_packer',
+      ],
+      'action': [
+        'python', '<(DEPTH)/build/android/gyp/pack_arm_relocations.py',
+        '--enable-packing=1',
+        '--exclude-packing-list=<@(exclude_packing_list)',
+        '--android-pack-relocations=<(PRODUCT_DIR)/relocation_packer',
+        '--android-objcopy=<(android_objcopy)',
+        '--stripped-libraries-dir=<(stripped_libraries_dir)',
+        '--packed-libraries-dir=<(packed_libraries_dir)',
+        '--libraries-file=<(ordered_libraries_file)',
+        '--stamp=<(stamp)',
+      ],
+    }, {
+      'message': 'Copying libraries (no relocation packing) for <(_target_name)',
+      'action': [
+        'python', '<(DEPTH)/build/android/gyp/pack_arm_relocations.py',
+        '--enable-packing=0',
+        '--stripped-libraries-dir=<(stripped_libraries_dir)',
+        '--packed-libraries-dir=<(packed_libraries_dir)',
+        '--libraries-file=<(ordered_libraries_file)',
+        '--stamp=<(stamp)',
+      ],
+    }],
+    ['component == "shared_library"', {
+      # Add a fake output to force the build to always re-run this step. This
+      # is required because the real inputs are not known at gyp-time and
+      # changing base.so may not trigger changes to dependent libraries.
+      'outputs': [ '<(stamp).fake' ]
+    }],
+  ],
+}
diff --git a/build/common.gypi b/build/common.gypi
index f5ab488..37c7fc8 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1703,6 +1703,9 @@
         'android_stlport_libs_dir': '<(android_stlport_root)/libs/<(android_app_abi)',
         'host_os%': '<(host_os)',
 
+        # Location of the "objcopy" binary, used by both gyp and scripts.
+        'android_objcopy%' : '<!(/bin/echo -n <(android_toolchain)/*-objcopy)',
+
         # Location of the "strip" binary, used by both gyp and scripts.
         'android_strip%' : '<!(/bin/echo -n <(android_toolchain)/*-strip)',
 
diff --git a/build/java_apk.gypi b/build/java_apk.gypi
index 4b0046b1..c860946 100644
--- a/build/java_apk.gypi
+++ b/build/java_apk.gypi
@@ -48,6 +48,8 @@
 #    RELRO section of the native libraries between the different processes.
 #  load_library_from_zip_file - When using the dynamic linker, load the library
 #    directly out of the zip file.
+#  use_relocation_packer - Enable relocation packing. Relies on the chromium
+#    linker, so use_chromium_linker must also be enabled.
 #  enable_chromium_linker_tests - Enable the content dynamic linker test support
 #    code. This allows a test APK to inject a Linker.TestRunner instance at
 #    runtime. Should only be used by the chromium_linker_test_apk target!!
@@ -95,7 +97,9 @@
     'instr_stamp': '<(intermediate_dir)/instr.stamp',
     'jar_stamp': '<(intermediate_dir)/jar.stamp',
     'obfuscate_stamp': '<(intermediate_dir)/obfuscate.stamp',
+    'pack_arm_relocations_stamp': '<(intermediate_dir)/pack_arm_relocations.stamp',
     'strip_stamp': '<(intermediate_dir)/strip.stamp',
+    'stripped_libraries_dir': '<(SHARED_INTERMEDIATE_DIR)/stripped_libraries',
     'classes_dir': '<(intermediate_dir)/classes/2',
     'javac_includes': [],
     'jar_excluded_classes': [],
@@ -127,6 +131,7 @@
         'native_lib_version_name%': '',
         'use_chromium_linker%' : 0,
         'load_library_from_zip_file%' : 0,
+        'use_relocation_packer%' : 0,
         'enable_chromium_linker_tests%': 0,
         'is_test_apk%': 0,
       },
@@ -151,11 +156,13 @@
     'native_lib_target%': '',
     'native_lib_version_name%': '',
     'use_chromium_linker%' : 0,
-    'enable_chromium_linker_tests%': 0,
     'load_library_from_zip_file%' : 0,
+    'use_relocation_packer%' : 0,
+    'enable_chromium_linker_tests%': 0,
     'emma_instrument%': '<(emma_instrument)',
     'apk_package_native_libs_dir': '<(apk_package_native_libs_dir)',
     'unsigned_standalone_apk_path': '<(unsigned_standalone_apk_path)',
+    'libchromium_android_linker': 'libchromium_android_linker.>(android_product_extension)',
     'extra_native_libs': [],
   },
   # Pass the jar path to the apk's "fake" jar target.  This would be better as
@@ -227,7 +234,7 @@
               ['use_chromium_linker == 1', {
                 'variables': {
                   'linker_input_libraries': [
-                    '<(SHARED_LIB_DIR)/libchromium_android_linker.>(android_product_extension)',
+                    '<(SHARED_LIB_DIR)/<(libchromium_android_linker)',
                   ],
                 }
               }, {
@@ -332,7 +339,7 @@
           'action_name': 'strip_native_libraries',
           'variables': {
             'ordered_libraries_file%': '<(ordered_libraries_file)',
-            'stripped_libraries_dir': '<(libraries_source_dir)',
+            'stripped_libraries_dir%': '<(stripped_libraries_dir)',
             'input_paths': [
               '<@(native_libs_paths)',
               '<@(extra_native_libs)',
@@ -341,6 +348,32 @@
           },
           'includes': ['../build/android/strip_native_libraries.gypi'],
         },
+        {
+          'action_name': 'pack_arm_relocations',
+          'variables': {
+            'conditions': [
+              ['use_chromium_linker == 1 and use_relocation_packer == 1', {
+                'enable_packing': 1,
+              }, {
+                'enable_packing': 0,
+              }],
+            ],
+            'exclude_packing_list': [
+              '<(libchromium_android_linker)',
+            ],
+            'ordered_libraries_file%': '<(ordered_libraries_file)',
+            'stripped_libraries_dir%': '<(stripped_libraries_dir)',
+            'packed_libraries_dir': '<(libraries_source_dir)',
+            'input_paths': [
+              '<(strip_stamp)',
+            ],
+            'stamp': '<(pack_arm_relocations_stamp)',
+          },
+          'dependencies': [
+            'strip_native_libraries',
+          ],
+          'includes': ['../build/android/pack_arm_relocations.gypi'],
+        },
       ],
       'conditions': [
         ['gyp_managed_install == 1', {