[iOS/GN] Fix generation of .dSYM for fat binary builds.

build/config/mac/BUILD.gn

 # Copyright (c) 2013 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/sysroot.gni")
+import("//build/config/ios/ios_sdk.gni")
 import("//build/config/mac/mac_sdk.gni")
 import("//build/config/mac/symbols.gni")
 
 # This is included by reference in the //build/config/compiler config that
 # is applied to all targets. It is here to separate out the logic.
 #
 # This is applied to BOTH desktop Mac and iOS targets.
 config("compiler") {
   # These flags are shared between the C compiler and linker.
   common_mac_flags = []
@@ skipping 26 matching lines @@
 
   # Without this, the constructors and destructors of a C++ object inside
   # an Objective C struct won't be called, which is very bad.
   cflags_objcc = [ "-fobjc-call-cxx-cdtors" ]
 
   cflags_c = [ "-std=c99" ]
   cflags_objc = cflags_c
 
   ldflags = common_mac_flags
 
-  if (save_unstripped_output) {
+  if (is_ios && additional_toolchains != []) {
+    # For fat build, the generation of the dSYM happens after the fat binary has
+    # been created with "lipo" thus the stripping cannot happen at link time but
+    # after running "lipo" too.
+    _save_unstripped_output = false
+  } else {
+    _save_unstripped_output = save_unstripped_output
+  }
+
+  if (_save_unstripped_output) {
     ldflags += [ "-Wcrl,unstripped," + rebase_path(root_out_dir) ]
   }
 }
 
 # This is included by reference in the //build/config/compiler:runtime_library
 # config that is applied to all targets. It is here to separate out the logic
 # that is Mac-only. Please see that target for advice on what should go in
 # :runtime_library vs. :compiler.
 config("runtime_library") {
   common_flags = [
@@ skipping 37 matching lines @@
   ldflags = [ "-Wl,-pie" ]  # Position independent.
 }
 
 # The ldflags referenced below are handled by
 # //build/toolchain/mac/linker_driver.py.
 # Remove this config if a target wishes to change the arguments passed to the
 # strip command during linking. This config by default strips all symbols
 # from a binary, but some targets may wish to specify a saves file to preserve
 # specific symbols.
 config("strip_all") {
-  if (enable_stripping) {
+  if (is_ios && additional_toolchains != []) {
+    # For fat build, the generation of the dSYM happens after the fat binary has
+    # been created with "lipo" thus the stripping cannot happen at link time but
+    # after running "lipo" too.
+    _enable_stripping = false
+  } else {
+    _enable_stripping = enable_stripping
+  }
+
+  if (_enable_stripping) {
     ldflags = [ "-Wcrl,strip,-x,-S" ]
   }
 }