build, win: make LTCG optional

Disables Link Time Code Generation by default. Adds ‘ltcg’ vcbuild
option to enable it. LTCG will be used by default by release and CI
builds.

PR-URL: #21186
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: bzoz

common.gypi

@@ -16,6 +16,7 @@
     'node_use_v8_platform%': 'true',
     'node_use_bundled_v8%': 'true',
     'node_module_version%': '',
+    'node_with_ltcg%': '',
 
     'node_tag%': '',
     'uv_library%': 'static_library',
@@ -192,36 +193,51 @@
                 'RuntimeLibrary': 0 # MultiThreaded (/MT)
               }
             }
+          }],
+          ['node_with_ltcg=="true"', {
+            'msvs_settings': {
+              'VCCLCompilerTool': {
+                'WholeProgramOptimization': 'true' # /GL, whole program optimization, needed for LTCG
+              },
+              'VCLibrarianTool': {
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL', # link time code generation
+                ]
+              },
+              'VCLinkerTool': {
+                'OptimizeReferences': 2, # /OPT:REF
+                'EnableCOMDATFolding': 2, # /OPT:ICF
+                'LinkIncremental': 1, # disable incremental linking
+                'AdditionalOptions': [
+                  '/LTCG:INCREMENTAL', # incremental link-time code generation
+                ]
+              }
+            }
+          }, {
+            'msvs_settings': {
+              'VCCLCompilerTool': {
+                'WholeProgramOptimization': 'false'
+              },
+              'VCLinkerTool': {
+                'LinkIncremental': 2 # enable incremental linking
+              }
+            }
           }]
         ],
         'msvs_settings': {
           'VCCLCompilerTool': {
             'Optimization': 3, # /Ox, full optimization
             'FavorSizeOrSpeed': 1, # /Ot, favor speed over size
             'InlineFunctionExpansion': 2, # /Ob2, inline anything eligible
-            'WholeProgramOptimization': 'true', # /GL, whole program optimization, needed for LTCG
             'OmitFramePointers': 'true',
             'EnableFunctionLevelLinking': 'true',
             'EnableIntrinsicFunctions': 'true',
             'RuntimeTypeInfo': 'false',
             'AdditionalOptions': [
               '/MP', # compile across multiple CPUs
             ],
-          },
-          'VCLibrarianTool': {
-            'AdditionalOptions': [
-              '/LTCG', # link time code generation
-            ],
-          },
-          'VCLinkerTool': {
-            'OptimizeReferences': 2, # /OPT:REF
-            'EnableCOMDATFolding': 2, # /OPT:ICF
-            'LinkIncremental': 1, # disable incremental linking
-            'AdditionalOptions': [
-              '/LTCG:INCREMENTAL', # incremental link-time code generation
-            ],
-          },
-        },
+          }
+        }
       }
     },
     # Forcibly disable -Werror.  We support a wide range of compilers, it's

configure

@@ -425,6 +425,11 @@ intl_optgroup.add_option('--with-icu-source',
     dest='with_icu_source',
     help='Intl mode: optional local path to icu/ dir, or path/URL of icu source archive.')
 
+parser.add_option('--with-ltcg',
+    action='store_true',
+    dest='with_ltcg',
+    help='Use Link Time Code Generation. This feature is only available on Windows.')
+
 intl_optgroup.add_option('--download',
     action='store',
     dest='download_list',
@@ -953,6 +958,10 @@ def configure_node(o):
   else:
     o['variables']['node_use_perfctr'] = 'false'
 
+  o['variables']['node_with_ltcg'] = b(options.with_ltcg)
+  if flavor != 'win' and options.with_ltcg:
+    raise Exception('Link Time Code Generation is only supported on Windows.')
+
   if options.tag:
     o['variables']['node_tag'] = '-' + options.tag
   else:

vcbuild.bat

@@ -15,6 +15,7 @@ cd %~dp0
 set config=Release
 set target=Build
 set target_arch=x64
+set ltcg=
 set target_env=
 set noprojgen=
 set projgen=
@@ -61,7 +62,7 @@ set doc=
 :next-arg
 if "%1"=="" goto args-done
 if /i "%1"=="debug"         set config=Debug&goto arg-ok
-if /i "%1"=="release"       set config=Release&goto arg-ok
+if /i "%1"=="release"       set config=Release&set ltcg=1&goto arg-ok
 if /i "%1"=="clean"         set target=Clean&goto arg-ok
 if /i "%1"=="ia32"          set target_arch=x86&goto arg-ok
 if /i "%1"=="x86"           set target_arch=x86&goto arg-ok
@@ -75,6 +76,7 @@ if /i "%1"=="sign"          set sign=1&goto arg-ok
 if /i "%1"=="nosnapshot"    set nosnapshot=1&goto arg-ok
 if /i "%1"=="noetw"         set noetw=1&goto arg-ok
 if /i "%1"=="noperfctr"     set noperfctr=1&goto arg-ok
+if /i "%1"=="ltcg"          set ltcg=1&goto arg-ok
 if /i "%1"=="licensertf"    set licensertf=1&goto arg-ok
 if /i "%1"=="test"          set test_args=%test_args% -J %common_test_suites%&set lint_cpp=1&set lint_js=1&set lint_md=1&goto arg-ok
 if /i "%1"=="test-ci"       set test_args=%test_args% %test_ci_args% -p tap --logfile test.tap %common_test_suites%&set cctest_args=%cctest_args% --gtest_output=tap:cctest.tap&goto arg-ok
@@ -150,6 +152,7 @@ if defined build_release (
   set download_arg="--download=all"
   set i18n_arg=small-icu
   set projgen=1
+  set ltcg=1
 )
 
 :: assign path to node_exe
@@ -162,6 +165,7 @@ if "%config%"=="Debug"      set configure_flags=%configure_flags% --debug
 if defined nosnapshot       set configure_flags=%configure_flags% --without-snapshot
 if defined noetw            set configure_flags=%configure_flags% --without-etw& set noetw_msi_arg=/p:NoETW=1
 if defined noperfctr        set configure_flags=%configure_flags% --without-perfctr& set noperfctr_msi_arg=/p:NoPerfCtr=1
+if defined ltcg             set configure_flags=%configure_flags% --with-ltcg
 if defined release_urlbase  set configure_flags=%configure_flags% --release-urlbase=%release_urlbase%
 if defined download_arg     set configure_flags=%configure_flags% %download_arg%
 if defined enable_vtune_arg set configure_flags=%configure_flags% --enable-vtune-profiling
@@ -656,7 +660,7 @@ del .used_configure_flags
 goto exit
 
 :help
-echo vcbuild.bat [debug/release] [msi] [doc] [test/test-ci/test-all/test-addons/test-addons-napi/test-internet/test-pummel/test-simple/test-message/test-gc/test-tick-processor/test-known-issues/test-node-inspect/test-check-deopts/test-npm/test-async-hooks/test-v8/test-v8-intl/test-v8-benchmarks/test-v8-all] [ignore-flaky] [static/dll] [noprojgen] [projgen] [small-icu/full-icu/without-intl] [nobuild] [nosnapshot] [noetw] [noperfctr] [licensetf] [sign] [ia32/x86/x64] [vs2017] [download-all] [enable-vtune] [lint/lint-ci/lint-js/lint-js-ci/lint-md] [lint-md-build] [package] [build-release] [upload] [no-NODE-OPTIONS] [link-module path-to-module] [debug-http2] [debug-nghttp2] [clean] [no-cctest] [openssl-no-asm]
+echo vcbuild.bat [debug/release] [msi] [doc] [test/test-ci/test-all/test-addons/test-addons-napi/test-internet/test-pummel/test-simple/test-message/test-gc/test-tick-processor/test-known-issues/test-node-inspect/test-check-deopts/test-npm/test-async-hooks/test-v8/test-v8-intl/test-v8-benchmarks/test-v8-all] [ignore-flaky] [static/dll] [noprojgen] [projgen] [small-icu/full-icu/without-intl] [nobuild] [nosnapshot] [noetw] [noperfctr] [ltcg] [licensetf] [sign] [ia32/x86/x64] [vs2017] [download-all] [enable-vtune] [lint/lint-ci/lint-js/lint-js-ci/lint-md] [lint-md-build] [package] [build-release] [upload] [no-NODE-OPTIONS] [link-module path-to-module] [debug-http2] [debug-nghttp2] [clean] [no-cctest] [openssl-no-asm]
 echo Examples:
 echo   vcbuild.bat                          : builds release build
 echo   vcbuild.bat debug                    : builds debug build