Enable whole-program virtual function optimization in LTO mode.

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 6131 matching lines @@
         },
       },
     }],
     # Apply a lower LTO optimization level as the default is too slow.
     ['use_lto==1 and clang==1', {
       'target_defaults': {
         'target_conditions': [
           ['_toolset=="target"', {
             'ldflags': [
               '-Wl,--plugin-opt,O1',
+              # Allows the linker to apply ICF to the LTO object file. Also, when
+              # targeting ARM, wWithout this flag, LTO produces a .text section
+              # that is larger than the maximum call displacement, preventing the
+              # linker from relocating calls (http://llvm.org/PR22999).
+              '-Wl,--plugin-opt,-function-sections',
             ],
           }],
           ['_toolset=="target" and _type!="static_library"', {
             'xcode_settings':  {
               'OTHER_LDFLAGS': [
                 '-Wl,-mllvm,-O1',
               ],
             },
           }],
         ],
         'msvs_settings': {
           'VCLinkerTool': {
             'AdditionalOptions': [
               '/opt:lldlto=1',
             ],
           },
         },
       },
     }],
-    ['use_lto==1 and clang==1 and target_arch=="arm"', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            # Without this flag, LTO produces a .text section that is larger
-            # than the maximum call displacement, preventing the linker from
-            # relocating calls (http://llvm.org/PR22999).
-            'ldflags': [
-              '-Wl,-plugin-opt,-function-sections',
-            ],
-          }],
-        ],
-      },
-    }],
     ['(use_lto==1 or use_lto_o2==1) and clang==0', {
       'target_defaults': {
         'target_conditions': [
           ['_toolset=="target"', {
             'ldflags': [
               '-flto=32',
             ],
           }],
         ],
       },
@@ skipping 125 matching lines @@
                   '-fsanitize-blacklist=<(cfi_blacklist)',
                   '-Xclang',
                   '-fsanitize-blacklist=../../<(make_clang_dir)/lib/clang/<!(python <(DEPTH)/tools/clang/scripts/update.py --print-clang-version)/cfi_blacklist.txt',
                 ],
               },
             },
           }],
         ],
       },
     }],
+    # TODO(pcc): Make these flags work correctly with CFI.
+    ['use_lto!=0 and cfi_vptr==0', {
+      'target_defaults': {
+        'target_conditions': [
+          ['_toolset=="target"', {
+            'cflags': [
+              '-fwhole-program-vtables',
+              # TODO(pcc): Remove this flag once the upstream interface change
+              # (http://reviews.llvm.org/D18635) lands.
+              '-fwhole-program-vtables-blacklist=<(cfi_blacklist)',
+            ],
+            'ldflags': [
+              '-fwhole-program-vtables',
+            ],
+          }],
+        ],
+      },
+    }],
   ],
   'xcode_settings': {
     # DON'T ADD ANYTHING NEW TO THIS BLOCK UNLESS YOU REALLY REALLY NEED IT!
     # This block adds *project-wide* configuration settings to each project
     # file.  It's almost always wrong to put things here.  Specify your
     # custom xcode_settings in target_defaults to add them to targets instead.
 
     'conditions': [
       # In an Xcode Project Info window, the "Base SDK for All Configurations"
       # setting sets the SDK on a project-wide basis. In order to get the
@@ skipping 36 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',
   },
 }