[Android Unwinder] Add new unwind info generation to build script

This CL adds the generation of the new unwind info to build script
behind a build flag "use_android_unwinder_v2".

Bug: 1240698
Change-Id: Ie63879b5396f03f2253ff1f79f2c4d00c69ef108
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3259978
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Commit-Queue: Charlie Hu <chenleihu@google.com>
Cr-Commit-Position: refs/heads/main@{#949287}

build/android/gyp/create_unwind_table.py

@@ -5,14 +5,20 @@
 """Creates a table of unwind information in Android Chrome's bespoke format."""
 
 import abc
+import argparse
+import collections
 import enum
 import logging
+import os
 import re
-import collections
 import struct
+import subprocess
+import sys
 from typing import (Dict, Iterable, List, NamedTuple, Sequence, TextIO, Tuple,
                     Union)
 
+from util import build_utils
+
 _STACK_CFI_INIT_REGEX = re.compile(
     r'^STACK CFI INIT ([0-9a-f]+) ([0-9a-f]+) (.+)$')
 _STACK_CFI_REGEX = re.compile(r'^STACK CFI ([0-9a-f]+) (.+)$')
@@ -653,6 +659,7 @@ def GetPageOffset(address: int) -> int:
   text_section_start_address: int = sorted_function_unwinds[0].address
   prev_func_end_address: int = sorted_function_unwinds[0].address
 
+  gaps = 0
   for unwind in sorted_function_unwinds:
     assert prev_func_end_address <= unwind.address, (
         'Detected overlap between functions.')
@@ -661,6 +668,7 @@ def GetPageOffset(address: int) -> int:
       # Gaps between functions are typically filled by regions of thunks which
       # do not alter the stack pointer. Filling these gaps with TRIVIAL_UNWIND
       # is the appropriate unwind strategy.
+      gaps += 1
       yield EncodedFunctionUnwind(GetPageNumber(prev_func_end_address),
                                   GetPageOffset(prev_func_end_address),
                                   TRIVIAL_UNWIND)
@@ -676,6 +684,9 @@ def GetPageOffset(address: int) -> int:
                                 GetPageOffset(prev_func_end_address),
                                 REFUSE_TO_UNWIND)
 
+  logging.info('%d/%d gaps between functions filled with trivial unwind.', gaps,
+               len(sorted_function_unwinds))
+
 
 def EncodeFunctionOffsetTable(
     encoded_address_unwind_sequences: Iterable[
@@ -869,8 +880,8 @@ def GenerateUnwinds(function_cfis: Iterable[FunctionCfi],
         epilogues_seen += 1
         break
 
-      logging.info('unrecognized CFI: %x %s.' %
-                   (address_cfi.address, address_cfi.unwind_instructions))
+      logging.info('unrecognized CFI: %x %s.', address_cfi.address,
+                   address_cfi.unwind_instructions)
 
     if address_unwinds:
       # We expect that the unwind information for every function starts with a
@@ -996,3 +1007,47 @@ def GenerateUnwindTables(
 
   return (page_table, function_table, function_offset_table,
           unwind_instruction_table)
+
+
+def main():
+  build_utils.InitLogging('CREATE_UNWIND_TABLE_DEBUG')
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument('--input_path',
+                      help='Path to the unstripped binary.',
+                      required=True,
+                      metavar='FILE')
+  parser.add_argument('--output_path',
+                      help='Path to unwind info binary output.',
+                      required=True,
+                      metavar='FILE')
+  parser.add_argument('--dump_syms_path',
+                      required=True,
+                      help='The path of the dump_syms binary.',
+                      metavar='FILE')
+
+  args = parser.parse_args()
+  proc = subprocess.Popen(['./' + args.dump_syms_path, args.input_path, '-v'],
+                          stdout=subprocess.PIPE,
+                          encoding='ascii')
+
+  function_cfis = ReadFunctionCfi(proc.stdout)
+  function_unwinds = GenerateUnwinds(function_cfis, parsers=ALL_PARSERS)
+  encoded_function_unwinds = EncodeFunctionUnwinds(function_unwinds)
+  (page_table, function_table, function_offset_table,
+   unwind_instruction_table) = GenerateUnwindTables(encoded_function_unwinds)
+  unwind_info: bytes = EncodeUnwindInfo(page_table, function_table,
+                                        function_offset_table,
+                                        unwind_instruction_table)
+
+  if proc.wait():
+    logging.critical('dump_syms exited with return code %d', proc.returncode)
+    sys.exit(proc.returncode)
+
+  with open(args.output_path, 'wb') as f:
+    f.write(unwind_info)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())

build/config/android/create_unwind_table.gni

@@ -0,0 +1,44 @@
+# Copyright 2021 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.
+
+import("//build/config/android/rules.gni")
+
+template("unwind_table_asset_v2") {
+  _asset_path = "${target_out_dir}/${target_name}/unwind_cfi_32_v2"
+  _unwind_action = "${target_name}__create_unwind_table"
+
+  action(_unwind_action) {
+    forward_variables_from(invoker, TESTONLY_AND_VISIBILITY)
+
+    _root_dir = "$root_out_dir"
+    if (defined(android_secondary_abi_cpu)) {
+      _root_dir = get_label_info(":foo($android_secondary_abi_toolchain)",
+                                 "root_out_dir")
+    }
+
+    script = "//build/android/gyp/create_unwind_table.py"
+    outputs = [ _asset_path ]
+    inputs = [ "${_root_dir}/lib.unstripped/$shlib_prefix${invoker.library_target}$shlib_extension" ]
+
+    args = [
+      "--input_path",
+      rebase_path(
+          "${_root_dir}/lib.unstripped/$shlib_prefix${invoker.library_target}$shlib_extension",
+          root_build_dir),
+      "--output_path",
+      rebase_path(_asset_path, root_build_dir),
+      "--dump_syms_path",
+      rebase_path("$root_out_dir/dump_syms", root_build_dir),
+    ]
+    deps = invoker.deps
+    deps += [ "//third_party/breakpad:dump_syms" ]
+  }
+
+  android_assets(target_name) {
+    forward_variables_from(invoker, TESTONLY_AND_VISIBILITY)
+    sources = [ _asset_path ]
+    disable_compression = true
+    deps = [ ":$_unwind_action" ]
+  }
+}

build/config/compiler/compiler.gni

@@ -204,6 +204,9 @@ can_unwind_with_cfi_table = is_android && !is_component_build &&
 enable_arm_cfi_table = is_android && !is_component_build && current_cpu == "arm"
 
 declare_args() {
+  # Set to true to use the android unwinder V2 implementation.
+  use_android_unwinder_v2 = false
+
   # If this running on a GPU FYI bot.
   # TODO(https://crbug.com/1233871): Remove this again.
   is_gpu_fyi_bot = false

chrome/android/chrome_public_apk_tmpl.gni

@@ -5,6 +5,7 @@
 import("//android_webview/variables.gni")
 import("//base/android/linker/config.gni")
 import("//base/android/resource_exclusions.gni")
+import("//build/config/android/create_unwind_table.gni")
 import("//build/config/android/extract_unwind_tables.gni")
 import("//build/config/android/rules.gni")
 import("//build/config/compiler/compiler.gni")
@@ -100,25 +101,46 @@ template("chrome_public_common_apk_or_module_tmpl") {
 
   if (_add_unwind_tables) {
     _unwind_asset_target = "${target_name}__unwind_assets"
-    unwind_table_asset(_unwind_asset_target) {
-      if (defined(invoker.testonly)) {
-        testonly = invoker.testonly
-      }
 
-      if (defined(invoker.shared_library_for_unwind_asset)) {
-        library_target = invoker.shared_library_for_unwind_asset
-      } else {
-        if (_is_monochrome || _is_trichrome) {
+    if (use_android_unwinder_v2) {
+      unwind_table_asset_v2(_unwind_asset_target) {
+        if (defined(invoker.testonly)) {
+          testonly = invoker.testonly
+        }
+
+        if (defined(invoker.shared_library_for_unwind_asset)) {
+          library_target = invoker.shared_library_for_unwind_asset
+        } else if (_is_monochrome || _is_trichrome) {
           library_target = "monochrome"
         } else {
           library_target = "chrome"
         }
+
+        if (android_64bit_target_cpu) {
+          deps = [ "//chrome/android:lib${library_target}($android_secondary_abi_toolchain)" ]
+        } else {
+          deps = [ "//chrome/android:lib${library_target}" ]
+        }
       }
+    } else {
+      unwind_table_asset(_unwind_asset_target) {
+        if (defined(invoker.testonly)) {
+          testonly = invoker.testonly
+        }
 
-      if (android_64bit_target_cpu) {
-        deps = [ "//chrome/android:lib${library_target}($android_secondary_abi_toolchain)" ]
-      } else {
-        deps = [ "//chrome/android:lib${library_target}" ]
+        if (defined(invoker.shared_library_for_unwind_asset)) {
+          library_target = invoker.shared_library_for_unwind_asset
+        } else if (_is_monochrome || _is_trichrome) {
+          library_target = "monochrome"
+        } else {
+          library_target = "chrome"
+        }
+
+        if (android_64bit_target_cpu) {
+          deps = [ "//chrome/android:lib${library_target}($android_secondary_abi_toolchain)" ]
+        } else {
+          deps = [ "//chrome/android:lib${library_target}" ]
+        }
       }
     }
   } else if (defined(invoker.shared_library_for_unwind_asset)) {

testing/test.gni

@@ -23,6 +23,7 @@ declare_args() {
 
 if (is_android) {
   import("//build/config/android/config.gni")
+  import("//build/config/android/create_unwind_table.gni")
   import("//build/config/android/extract_unwind_tables.gni")
   import("//build/config/android/rules.gni")
   import("//build/config/sanitizers/sanitizers.gni")
@@ -198,9 +199,16 @@ template("test") {
       if (defined(invoker.add_unwind_tables_in_apk) &&
           invoker.add_unwind_tables_in_apk) {
         _unwind_table_asset_name = "${target_name}_unwind_assets"
-        unwind_table_asset(_unwind_table_asset_name) {
-          library_target = _library_target
-          deps = [ ":$_library_target" ]
+        if (use_android_unwinder_v2) {
+          unwind_table_asset_v2(_unwind_table_asset_name) {
+            library_target = _library_target
+            deps = [ ":$_library_target" ]
+          }
+        } else {
+          unwind_table_asset(_unwind_table_asset_name) {
+            library_target = _library_target
+            deps = [ ":$_library_target" ]
+          }
         }
       }