Android: Make enable_resource_whitelist_generation GN arg work when setting to true

Also:
 * Default the arg to true for all release builds that contain debug info.
   (most bots set strip_debug_info=true though)
 * Add better failure messages for when no debug info is present.

Bug: 864878
Change-Id: Ied849d6e24a672b896c802be6df6c0958ecabfe0
Reviewed-on: https://chromium-review.googlesource.com/1142193
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: Richard Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#588734}

build/config/android/config.gni

@@ -355,9 +355,3 @@ if (is_android || is_chromeos) {
     android_libcpp_lib_dir = "${android_libcpp_root}/libs/${android_app_abi}"
   }
 }
-
-declare_args() {
-  # Enables used resource whitelist generation. Set for official builds only
-  # as a large amount of build output is generated.
-  enable_resource_whitelist_generation = is_android && is_official_build
-}

build/config/compiler/BUILD.gn

@@ -102,9 +102,6 @@ declare_args() {
   # Allow projects that wish to stay on C++11 to override Chromium's default.
   use_cxx11 = false
 
-  # Strip the debug info of symbols file in lib.unstripped to reduce size.
-  strip_debug_info = false
-
   # Path to an AFDO profile to use while building with clang, if any. Empty
   # implies none.
   clang_sample_profile_path = ""

build/config/compiler/compiler.gni

@@ -25,6 +25,11 @@ declare_args() {
   #   -1 means auto-set according to debug/release and platform.
   symbol_level = -1
 
+  # Android-only: Strip the debug info of libraries within lib.unstripped to
+  # reduce size. As long as symbol_level > 0, this will still allow stacks to be
+  # symbolized.
+  strip_debug_info = false
+
   # Compile in such a way as to enable profiling of the generated code. For
   # example, don't omit the frame pointer and leave in symbols.
   enable_profiling = false

build/toolchain/android/BUILD.gn

@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/android/config.gni")
 import("//build/config/clang/clang.gni")
 import("//build/config/sysroot.gni")  # Imports android/config.gni.
 import("//build/toolchain/gcc_toolchain.gni")

build/toolchain/gcc_toolchain.gni

@@ -2,8 +2,8 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-import("//build/config/android/config.gni")
 import("//build/config/clang/clang.gni")
+import("//build/config/compiler/compiler.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/v8_target_cpu.gni")
 import("//build/toolchain/cc_wrapper.gni")
@@ -18,6 +18,21 @@ if (is_nacl) {
   import("//build/config/nacl/config.gni")
 }
 
+declare_args() {
+  # Enables whitelist generation for IDR_ grit defines seen by the compiler.
+  # Currently works only on Android and enabled by default for release builds.
+  # Requires debug info, so disabled for symbol_level=0 & strip_debug_info=true.
+  enable_resource_whitelist_generation =
+      is_android && !is_debug &&
+      (is_official_build || (!strip_debug_info && symbol_level > 0))
+}
+
+# When the arg is set via args.gn, it applies to all toolchains. In order to not
+# hit the assert in grit_rule.gni, explicitly disable for host toolchains.
+if (is_linux && target_os == "android") {
+  enable_resource_whitelist_generation = false
+}
+
 # Path to the Clang static analysis wrapper script.
 # REVIEWERS: can you suggest a better location for this?
 # GN is really picky about dead stores of variables except at the global scope.

tools/grit/grit/format/data_pack.py

@@ -221,8 +221,10 @@ def RePack(output_file, input_files, whitelist_file=None,
   input_info_files = [filename + '.info' for filename in input_files]
   whitelist = None
   if whitelist_file:
-    whitelist = util.ReadFile(whitelist_file, util.RAW_TEXT).strip().split('\n')
-    whitelist = set(map(int, whitelist))
+    lines = util.ReadFile(whitelist_file, util.RAW_TEXT).strip().splitlines()
+    if not lines:
+      raise Exception('Whitelist file should not be empty')
+    whitelist = set(int(x) for x in lines)
   inputs = [(p.resources, p.encoding) for p in input_data_packs]
   resources, encoding = RePackFromDataPackStrings(
       inputs, whitelist, suppress_removed_key_output)

tools/grit/grit_rule.gni

@@ -84,18 +84,20 @@
 #     # You can also put deps here if the grit source depends on generated
 #     # files.
 #   }
-import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/compute_inputs_for_analyze.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
+import("//build/toolchain/gcc_toolchain.gni")  # For enable_resource_whitelist_generation
 import("//third_party/closure_compiler/closure_args.gni")
 
 assert(
-    !enable_resource_whitelist_generation || (is_android && symbol_level > 0),
-    "resource whitelist generation only works on android with symbol_level > 0")
+    !enable_resource_whitelist_generation ||
+        (is_android && symbol_level > 0 && !strip_debug_info &&
+             !is_component_build),
+    "resource whitelist generation only works on non-component android builds with debug info enabled.")
 
 grit_defines = []
 

tools/resources/generate_resource_whitelist.py

@@ -25,7 +25,9 @@ def WriteResourceWhitelist(args):
   readelf = subprocess.Popen(
       ['readelf', '-p', '.debug_str', args.input], stdout=subprocess.PIPE)
   resource_ids = set()
+  output_exists = False
   for line in readelf.stdout:
+    output_exists = True
     # Read a line of the form "  [   123]  WhitelistedResource<456>". We're
     # only interested in the string, not the offset. We're also not interested
     # in header lines.
@@ -38,6 +40,10 @@ def WriteResourceWhitelist(args):
         resource_ids.add(int(s[len('WhitelistedResource<'):-len('>')-1]))
       except ValueError:
         continue
+  if not output_exists:
+    raise Exception('No debug info was dumpped. Ensure GN arg "symbol_level" '
+                    '!= 0 and that the file is not stripped.')
+
   for id in sorted(resource_ids):
     args.output.write(str(id) + '\n')
   exit_code = readelf.wait()