build: allow LTO with Clang 3.9.1+

Bug: #38568 Test: manual, - arm64-apple-darwin20.5.0 / Apple clang version 12.0.5 (clang-1205.0.22.9) - x86_64-pc-linux-gnu / Ubuntu clang version 13.0.0-++20210520052624+48780527dd68-1~exp1~20210520153429.417 Signed-off-by: Jesse Chan <jc@linux.com> PR-URL: #38751 Reviewed-By: Jiawen Geng <technicalcute@gmail.com> Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>

Author: jesec

common.gypi

@@ -164,17 +164,28 @@
  'v8_enable_handle_zapping': 0,
  'pgo_generate': ' -fprofile-generate ',
  'pgo_use': ' -fprofile-use -fprofile-correction ',
- 'lto': ' -flto=4 -fuse-linker-plugin -ffat-lto-objects ',
  'conditions': [
  ['node_shared != "true"', {
  'MSVC_runtimeType': 0 # MultiThreaded (/MT)
  }, {
  'MSVC_runtimeType': 2 # MultiThreadedDLL (/MD)
  }],
+ ['llvm_version=="0.0"', {
+ 'lto': ' -flto=4 -fuse-linker-plugin -ffat-lto-objects ', # GCC
+ }, {
+ 'lto': ' -flto ', # Clang
+ }],
  ],
  },
  'cflags': [ '-O3' ],
  'conditions': [
+ ['enable_lto=="true"', {
+ 'cflags': ['<(lto)'],
+ 'ldflags': ['<(lto)'],
+ 'xcode_settings': {
+ 'LLVM_LTO': 'YES',
+ },
+ }],
  ['OS=="linux"', {
  'conditions': [
  ['node_section_ordering_info!=""', {
@@ -206,10 +217,6 @@
  'cflags': ['<(pgo_use)'],
  'ldflags': ['<(pgo_use)'],
  },],
- ['enable_lto=="true"', {
- 'cflags': ['<(lto)'],
- 'ldflags': ['<(lto)'],
- },],
  ],
  },],
  ['OS == "android"', {

configure.py

@@ -173,7 +173,7 @@
  dest="enable_lto",
  default=None,
  help="Enable compiling with lto of a binary. This feature is only available "
- "on linux with gcc and g++ 5.4.1 or newer.")
+ "with gcc 5.4.1+ or clang 3.9.1+.")
 
 parser.add_argument("--link-module",
  action="append",
@@ -952,6 +952,7 @@ def get_gas_version(cc):
 # quite prepared to go that far yet.
 def check_compiler(o):
  if sys.platform == 'win32':
+ o['variables']['llvm_version'] = '0.0'
  if not options.openssl_no_asm and options.dest_cpu in ('x86', 'x64'):
  nasm_version = get_nasm_version('nasm')
  o['variables']['nasm_version'] = nasm_version
@@ -1131,12 +1132,19 @@ def configure_mips(o, target_arch):
  host_byteorder = 'little' if target_arch in ('mipsel', 'mips64el') else 'big'
  o['variables']['v8_host_byteorder'] = host_byteorder
 
+def clang_version_ge(version_checked):
+ for compiler in [(CC, 'c'), (CXX, 'c++')]:
+ ok, is_clang, clang_version, gcc_version = \
+ try_check_compiler(compiler[0], compiler[1])
+ if is_clang and clang_version >= version_checked:
+ return True
+ return False
 
 def gcc_version_ge(version_checked):
  for compiler in [(CC, 'c'), (CXX, 'c++')]:
- ok, is_clang, clang_version, compiler_version = \
+ ok, is_clang, clang_version, gcc_version = \
  try_check_compiler(compiler[0], compiler[1])
- if is_clang or compiler_version < version_checked:
+ if is_clang or gcc_version < version_checked:
  return False
  return True
 
@@ -1217,18 +1225,19 @@ def configure_node(o):
  o['variables']['enable_pgo_generate'] = b(options.enable_pgo_generate)
  o['variables']['enable_pgo_use'] = b(options.enable_pgo_use)
 
- if flavor != 'linux' and (options.enable_lto):
+ if flavor == 'win' and (options.enable_lto):
  raise Exception(
- 'The lto option is supported only on linux.')
-
- if flavor == 'linux':
- if options.enable_lto:
- version_checked = (5, 4, 1)
- if not gcc_version_ge(version_checked):
- version_checked_str = ".".join(map(str, version_checked))
- raise Exception(
- 'The option --enable-lto is supported for gcc and gxx %s'
- ' or newer only.' % (version_checked_str))
+ 'Use Link Time Code Generation instead.')
+
+ if options.enable_lto:
+ gcc_version_checked = (5, 4, 1)
+ clang_version_checked = (3, 9, 1)
+ if not gcc_version_ge(gcc_version_checked) and not clang_version_ge(clang_version_checked):
+ gcc_version_checked_str = ".".join(map(str, gcc_version_checked))
+ clang_version_checked_str = ".".join(map(str, clang_version_checked))
+ raise Exception(
+ 'The option --enable-lto is supported for gcc %s+'
+ 'or clang %s+ only.' % (gcc_version_checked_str, clang_version_checked_str))
 
  o['variables']['enable_lto'] = b(options.enable_lto)