Use gold and the bundled binutils on x86 by default

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 671 matching lines @@
       # $DYLD_LIBRARY_PATH to pick up the right version of the linker plugin.
       # TODO(pcc): Teach build system to use -lto_library flag to specify path
       # to linker plugin on Mac.
       #
       # On Android/GCC, the variables must *not* be enabled at the same time.
       # In this case LTO would 'merge' the optimization flags at link-time
       # which would lead to all code be optimized with -O2. See crbug.com/407544
       'use_lto%': 0,
       'use_lto_o2%': 0,
 
-      # Allowed level of identical code folding in the gold linker.
-      'gold_icf_level%': 'all',
-
       # Libxkbcommon usage.
       'use_xkbcommon%': 0,
 
       # Whether we use GTKv3 on linux.
       'use_gtk3%': 0,
 
       # Control Flow Integrity for virtual calls and casts.
       # See http://clang.llvm.org/docs/ControlFlowIntegrity.html
       'cfi_vptr%': 0,
       'cfi_diag%': 0,
@@ skipping 205 matching lines @@
         # Whether PPAPI is enabled.
         ['OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
           'enable_plugins%': 0,
         }, {
           'enable_plugins%': 1,
         }],
 
         # linux_use_bundled_gold: whether to use the gold linker binary checked
         # into third_party/binutils.  Force this off via GYP_DEFINES when you
         # are using a custom toolchain and need to control -B in ldflags.
-        # Do not use 32-bit gold on 32-bit hosts as it runs out address space
-        # for component=static_library builds.

[Nico, 2016/05/05 16:25:21]

This comment is obsolete, we switched to 64-bit host gold always quite a long
time ago.

-        ['(OS=="linux" or OS=="android") and (target_arch=="x64" or target_arch=="arm" or (target_arch=="ia32" and host_arch=="x64"))', {
+        ['(OS=="linux" or OS=="android") and (target_arch=="x64" or target_arch=="arm" or target_arch=="ia32")', {
           'linux_use_bundled_gold%': 1,
         }, {
           'linux_use_bundled_gold%': 0,
         }],
 
+        # Allowed level of identical code folding in the gold linker.
+        # icf=all is buggy on ia32, so disabled by default.

[Nico, 2016/05/05 16:25:21]

Where is this from? I can't see evidence of this, and it's new from what I can
tell.

+        ['(OS=="linux" and (target_arch=="ia32"))', {
+          'gold_icf_level%': 'none',
+        }, {
+          'gold_icf_level%': 'all',
+        }],
+
         # linux_use_bundled_binutils: whether to use the binary binutils
         # checked into third_party/binutils.  These are not multi-arch so cannot
         # be used except on x86 and x86-64 (the only two architectures which
         # are currently checke in).  Force this off via GYP_DEFINES when you
         # are using a custom toolchain and need to control -B in cflags.
         ['OS=="linux" and (target_arch=="x64")', {
           'linux_use_bundled_binutils%': 1,
         }, {
           'linux_use_bundled_binutils%': 0,
         }],
 
         # linux_use_gold_flags: whether to use build flags that rely on gold.
-        # On by default for x64 Linux.
-        ['OS=="linux" and target_arch=="x64"', {
+        ['OS=="linux" and (target_arch=="x64" or target_arch=="ia32" or target_arch=="arm")', {
           'linux_use_gold_flags%': 1,
         }, {
           'linux_use_gold_flags%': 0,
         }],
 
         # linux_use_debug_fission: whether to use split DWARF debug info
         # files. This can reduce link time significantly, but is incompatible
         # with some utilities such as icecc and ccache. Requires gold and
         # gcc >= 4.8 or clang.
         # http://gcc.gnu.org/wiki/DebugFission
@@ skipping 5372 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }