[ios] Strip arm64e from XCTRunner if present

With Xcode 11.4, the arm64e slice of XCTRunner is removed from the
binary when creating the XCUITest runner application. Not doing it
may prevents running the application on a device, so replicate this.

Bug: none
Change-Id: I25925ac7ed20150bb2ef4cffa01e64f8ad9d4e1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2127111
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754981}

build/config/ios/BUILD.gn

@@ -128,6 +128,9 @@ group("xctest") {
   public_configs = [ ":xctest_config" ]
 }
 
+_xctrunner_path =
+    "$ios_sdk_platform_abs_path/Developer/Library/Xcode/Agents/XCTRunner.app"
+
 # When building with Goma RBE, $ios_sdk_platform_abs_path corresponds to a
 # symlink below $root_build_dir that points to the real SDK to use. Because
 # the files are below $root_build_dir, it is not possible to list them as a
@@ -142,9 +145,6 @@ group("xctest") {
 # To workaround this, add a target that pretends to create those files
 # (but does nothing). See https://crbug.com/1061487 for why this is needed.
 if (ios_use_goma_rbe) {
-  _xctrunner_path =
-      "$ios_sdk_platform_abs_path/Developer/Library/Xcode/Agents/XCTRunner.app"
-
   action("copy_xctrunner_app") {
     testonly = true
     script = "//build/noop.py"
@@ -155,3 +155,23 @@ if (ios_use_goma_rbe) {
     ]
   }
 }
+
+# When creating the test runner for an XCUITest, the arm64e slice of the binary
+# must be removed (at least until the app ships with arm64e slice which is not
+# yet supported by Apple).
+action("xctest_runner_without_arm64e") {
+  testonly = true
+  script = "//build/config/ios/strip_arm64e.py"
+  sources = [ "$_xctrunner_path/XCTRunner" ]
+  outputs = [ "$target_out_dir/XCTRunner" ]
+  args = [
+    "--output",
+    rebase_path(outputs[0], root_build_dir),
+    "--input",
+    rebase_path(sources[0], root_build_dir),
+  ]
+
+  if (ios_use_goma_rbe) {
+    deps = [ ":copy_xctrunner_app" ]
+  }
+}

build/config/ios/rules.gni

@@ -1938,7 +1938,7 @@ template("ios_xcuitest_test_runner_bundle") {
     outputs = [ "{{bundle_contents_dir}}/PkgInfo" ]
 
     if (ios_use_goma_rbe) {
-      deps = [ "//build/config/ios:copy_xctrunner_app" ]
+      public_deps = [ "//build/config/ios:copy_xctrunner_app" ]
     }
   }
 
@@ -1946,7 +1946,8 @@ template("ios_xcuitest_test_runner_bundle") {
   create_signed_bundle(_target_name) {
     testonly = true
 
-    bundle_binary_path = "$_xctrunner_path/XCTRunner"
+    bundle_binary_target = "//build/config/ios:xctest_runner_without_arm64e"
+    bundle_binary_output = "XCTRunner"
     bundle_extension = ".app"
     product_type = "com.apple.product-type.application"
 
@@ -1969,10 +1970,6 @@ template("ios_xcuitest_test_runner_bundle") {
       ":$_pkginfo_bundle",
       ":$_xctest_bundle",
     ]
-
-    if (ios_use_goma_rbe) {
-      deps = [ "//build/config/ios:copy_xctrunner_app" ]
-    }
   }
 }
 

build/config/ios/strip_arm64e.py

+# Copyright 2020 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.
+"""Strip arm64e architecture from a binary if present."""
+
+import argparse
+import os
+import shutil
+import subprocess
+import sys
+
+
+def check_output(command):
+  """Returns the output from |command| or propagates error, quitting script."""
+  process = subprocess.Popen(
+      command, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+  outs, errs = process.communicate()
+  if process.returncode:
+    sys.stderr.write('error: command failed with retcode %d: %s\n\n' %
+                     (process.returncode, ' '.join(map(repr, command))))
+    sys.stderr.write(errs)
+    sys.exit(process.returncode)
+  return outs
+
+
+def check_call(command):
+  """Invokes |command| or propagates error."""
+  check_output(command)
+
+
+def parse_args(args):
+  """Parses the command-line."""
+  parser = argparse.ArgumentParser()
+  parser.add_argument('--input', required=True, help='Path to input binary')
+  parser.add_argument('--output', required=True, help='Path to output binary')
+  return parser.parse_args(args)
+
+
+def get_archs(path):
+  """Extracts the architectures present in binary at |path|."""
+  outputs = check_output(["xcrun", "lipo", "-info", os.path.abspath(path)])
+  return outputs.split(': ')[-1].split()
+
+
+def main(args):
+  parsed = parse_args(args)
+
+  outdir = os.path.dirname(parsed.output)
+  if not os.path.isdir(outdir):
+    os.makedirs(outdir)
+
+  if os.path.exists(parsed.output):
+    os.unlink(parsed.output)
+
+  # As "lipo" fails with an error if asked to remove an architecture that is
+  # not included, only use it if "arm64e" is present in the binary. Otherwise
+  # simply copy the file.
+  if 'arm64e' in get_archs(parsed.input):
+    check_output([
+        "xcrun", "lipo", "-remove", "arm64e", "-output",
+        os.path.abspath(parsed.output),
+        os.path.abspath(parsed.input)
+    ])
+  else:
+    shutil.copy(parsed.input, parsed.output)
+
+
+if __name__ == '__main__':
+  main(sys.argv[1:])