linux: add a use_gold flag that defaults to on

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 359 matching lines @@
         ['OS=="win" and MSVS_VERSION=="2010"', {
           'chromium_win_pch%': 1
         }],
 
         ['use_aura==1 or chromeos==1', {
           'enable_plugin_installation%': 0,
         }, {
           'enable_plugin_installation%': 1,
         }],
 
-        # Set to 0 to not use third_party/gold as the linker.
+        # linux_use_gold_binary: whether to use the binary checked into
+        # third_party/gold.
+        # linux_use_gold: whether to use build flags that rely on gold.

[Lei Zhang, 2012/02/04 01:09:13]

how about "linux_use_gold_flags"

[Evan Martin, 2012/02/08 18:33:53]

Done.

         # On by default for x64 Linux.  Off for ChromeOS as cross-compiling
         # makes things complicated.
         ['chromeos==0 and host_arch=="x64"', {
           'linux_use_gold_binary%': 1,
+          'linux_use_gold%': 1,
         }, {
           'linux_use_gold_binary%': 0,
+          'linux_use_gold%': 0,
         }],
       ],
     },
 
     # Copy conditionally-set variables out one scope.
     'branding%': '<(branding)',
     'buildtype%': '<(buildtype)',
     'target_arch%': '<(target_arch)',
     'host_arch%': '<(host_arch)',
     'library%': 'static_library',
@@ skipping 40 matching lines @@
     'input_speech%': '<(input_speech)',
     'notifications%': '<(notifications)',
     'clang_use_chrome_plugins%': '<(clang_use_chrome_plugins)',
     'asan%': '<(asan)',
     'order_text_section%': '<(order_text_section)',
     'enable_register_protocol_handler%': '<(enable_register_protocol_handler)',
     'enable_web_intents%': '<(enable_web_intents)',
     'enable_web_intents_tag%': '<(enable_web_intents_tag)',
     'enable_plugin_installation%': '<(enable_plugin_installation)',
     'linux_use_gold_binary%': '<(linux_use_gold_binary)',
+    'linux_use_gold%': '<(linux_use_gold)',
     'use_canvas_skia_skia%': '<(use_canvas_skia_skia)',
     # Whether to build for Wayland display server
     'use_wayland%': 0,
 
     # Use system yasm instead of bundled one.
     'use_system_yasm%': 0,
 
     # Default to enabled PIE; this is important for ASLR but we need to be
     # able to turn it off for remote debugging on Chromium OS
     'linux_disable_pie%': 0,
@@ skipping 1245 matching lines @@
                 'cflags!': [
                   '-fno-ident',
                 ],
               }],
               ['profiling==1', {
                 'cflags': [
                   '-fno-omit-frame-pointer',
                   '-g',
                 ],
               }],
-              # At gyp time, we test the linker for ICF support; this flag
-              # is then provided to us by gyp.  (Currently only gold supports
-              # an --icf flag.)
-              # There seems to be a conflict of --icf and -pie in gold which
-              # can generate crashy binaries. As a security measure, -pie
-              # takes precendence for now.
-              ['LINKER_SUPPORTS_ICF==1 and release_valgrind_build==0', {
-                'target_conditions': [
-                  ['_toolset=="target"', {
-                    'ldflags': [
-                      #'-Wl,--icf=safe',
-                      '-Wl,--icf=none',
-                    ]
-                  }]
-                ]
-              }],
-            ]
+            ],
           },
         },
         'variants': {
           'coverage': {
             'cflags': ['-fprofile-arcs', '-ftest-coverage'],
             'ldflags': ['-fprofile-arcs'],
           },
           'profile': {
             'cflags': ['-pg', '-g'],
             'ldflags': ['-pg'],
@@ skipping 245 matching lines @@
             'variables': {'linux_use_tcmalloc%': 1},
             'defines': ['USE_HEAPCHECKER'],
           }],
           ['linux_use_tcmalloc==0', {
             'defines': ['NO_TCMALLOC'],
           }],
           ['linux_keep_shadow_stacks==1', {
             'defines': ['KEEP_SHADOW_STACKS'],
             'cflags': ['-finstrument-functions'],
           }],
+          ['linux_use_gold==1', {

[Lei Zhang, 2012/02/04 01:09:13]

Do we need to take |release_valgrind_build| into account like we did in the
deleted block?

[Evan Martin, 2012/02/08 18:33:53]

Fixed.

+            'ldflags': [
+              # There seems to be a conflict of --icf and -pie in gold which
+              # can generate crashy binaries. As a security measure, -pie
+              # takes precendence for now.
+              #'-Wl,--icf=safe',
+              '-Wl,--icf=none',
+            ],
+          }],
           ['linux_use_gold_binary==1', {
             'variables': {
               # We pass the path to gold to the compiler.  gyp leaves
               # unspecified what the cwd is when running the compiler,
               # so the normal gyp path-munging fails us.  This hack
               # gets the right path.
               'gold_path': '<(PRODUCT_DIR)/../../third_party/gold',
             },
             'ldflags': [
               # Put our gold binary in the search path for the linker.
@@ skipping 757 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',
   },
 }