[build] Clean up lto, gold plugin and cfi from gyp files

Bug: v8:6524
Change-Id: I8e440417eea59376c2fab659a86ad6570c7e018a
Reviewed-on: https://chromium-review.googlesource.com/549300Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46265}

gypfiles/standalone.gypi

@@ -136,8 +136,6 @@
       'clang_dir%': '<(base_dir)/third_party/llvm-build/Release+Asserts',
       'make_clang_dir%': '<(base_dir)/third_party/llvm-build/Release+Asserts',
 
-      'use_lto%': 0,
-
       # Control Flow Integrity for virtual calls and casts.
       # See http://clang.llvm.org/docs/ControlFlowIntegrity.html
       'cfi_vptr%': 0,
@@ -202,7 +200,6 @@
     'use_prebuilt_instrumented_libraries%': '<(use_prebuilt_instrumented_libraries)',
     'use_custom_libcxx%': '<(use_custom_libcxx)',
     'linux_use_bundled_gold%': '<(linux_use_bundled_gold)',
-    'use_lto%': '<(use_lto)',
     'cfi_vptr%': '<(cfi_vptr)',
     'cfi_diag%': '<(cfi_diag)',
     'cfi_blacklist%': '<(cfi_blacklist)',
@@ -293,9 +290,6 @@
         # the C++ standard library is used.
         'use_custom_libcxx%': 1,
       }],
-      ['cfi_vptr==1', {
-        'use_lto%': 1,
-      }],
       ['OS=="android"', {
         # Location of Android NDK.
         'variables': {
@@ -679,15 +673,11 @@
               }],
             ],
           }],
-          ['linux_use_bundled_gold==1 and not (clang==0 and use_lto==1)', {
+          ['linux_use_bundled_gold==1', {
             # Put our binutils, which contains gold in the search path. 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.
-            #
-            # Disabled when using GCC LTO because GCC also uses the -B search
-            # path at link time to find "as", and our bundled "as" can only
-            # target x86.
             'ldflags': [
               # Note, Chromium allows ia32 host arch as well, we limit this to
               # x64 in v8.
@@ -1410,109 +1400,5 @@
         }],
       ],
     }],
-    ['use_lto==1', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'cflags': [
-              '-flto',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['use_lto==1 and clang==0', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'cflags': [
-              '-ffat-lto-objects',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['use_lto==1 and clang==1', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'arflags': [
-              '--plugin', '<(clang_dir)/lib/LLVMgold.so',
-            ],
-            # Apply a lower optimization level with lto. Chromium does this
-            # for non-official builds only - a differentiation that doesn't
-            # exist in v8.
-            'ldflags': [
-              '-Wl,--plugin-opt,O1',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['use_lto==1 and clang==0', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'ldflags': [
-              '-flto=32',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['use_lto==1 and clang==1', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'ldflags': [
-              '-flto',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['cfi_diag==1', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'cflags': [
-              '-fno-sanitize-trap=cfi',
-              '-fno-sanitize-recover=cfi',
-            ],
-            'cflags_cc!': [
-              '-fno-rtti',
-            ],
-            'cflags!': [
-              '-fno-rtti',
-            ],
-            'ldflags': [
-              '-fno-sanitize-trap=cfi',
-              '-fno-sanitize-recover=cfi',
-            ],
-          }],
-        ],
-      },
-    }],
-    ['cfi_vptr==1', {
-      'target_defaults': {
-        'target_conditions': [
-          ['_toolset=="target"', {
-            'cflags': [
-              '-fsanitize=cfi-vcall',
-              '-fsanitize=cfi-derived-cast',
-              '-fsanitize=cfi-unrelated-cast',
-              '-fsanitize-blacklist=<(cfi_blacklist)',
-              '-fwhole-program-vtables',
-            ],
-            'ldflags': [
-              '-fsanitize=cfi-vcall',
-              '-fsanitize=cfi-derived-cast',
-              '-fsanitize=cfi-unrelated-cast',
-              '-fwhole-program-vtables',
-            ],
-          }],
-        ],
-      },
-    }],
   ],
 }

gypfiles/toolchain.gypi

@@ -128,9 +128,6 @@
       }],
     ],
 
-    # Link-Time Optimizations
-    'use_lto%': 0,
-
     # Indicates if gcmole tools are downloaded by a hook.
     'gcmole%': 0,
   },
@@ -280,17 +277,6 @@
                   }],
                 ],
               }],
-              # Disable GCC LTO for v8
-              # v8 is optimized for speed. Because GCC LTO merges flags at link
-              # time, we disable LTO to prevent any -O2 flags from taking
-              # precedence over v8's -Os flag. However, LLVM LTO does not work
-              # this way so we keep LTO enabled under LLVM.
-              ['clang==0 and use_lto==1', {
-                'cflags!': [
-                  '-flto',
-                  '-ffat-lto-objects',
-                ],
-              }],
             ],
           }],  # _toolset=="target"
         ],
@@ -1284,9 +1270,7 @@
               }],
             ],
           }],
-          # TODO(pcc): Re-enable in LTO builds once we've fixed the intermittent
-          # link failures (crbug.com/513074).
-          ['linux_use_gold_flags==1 and use_lto==0', {
+          ['linux_use_gold_flags==1', {
             'target_conditions': [
               ['_toolset=="target"', {
                 'ldflags': [