build: harmonize Clang checks

- Set the clang variable in `config.gypi` so it depends on compiler
  checks made by the configure script.
- Replace gyp conditions with `llvm_version` and "0.0" with conditions
  that use the `clang` variable.
- Always use `clang==1` or `clang==0` in gyp conditions

PR-URL: https://github.com/nodejs/node/pull/52873
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Yagiz Nizipli <yagiz.nizipli@sentry.io>
Reviewed-By: Mohammed Keyvanzadeh <mohammadkeyvanzade94@gmail.com>

common.gypi

@@ -107,7 +107,6 @@
         'v8_base': '<(PRODUCT_DIR)/obj.target/tools/v8_gypfiles/libv8_snapshot.a',
       }],
       ['OS=="mac"', {
-        'clang%': 1,
         'obj_dir%': '<(PRODUCT_DIR)/obj.target',
         'v8_base': '<(PRODUCT_DIR)/libv8_snapshot.a',
       }],
@@ -182,10 +181,10 @@
             }, {
               'MSVC_runtimeType': 2   # MultiThreadedDLL (/MD)
             }],
-            ['llvm_version=="0.0"', {
-              'lto': ' -flto=4 -fuse-linker-plugin -ffat-lto-objects ', # GCC
-            }, {
+            ['clang==1', {
               'lto': ' -flto ', # Clang
+            }, {
+              'lto': ' -flto=4 -fuse-linker-plugin -ffat-lto-objects ', # GCC
             }],
           ],
         },

configure.py

@@ -1042,6 +1042,7 @@ def get_gas_version(cc):
 # quite prepared to go that far yet.
 def check_compiler(o):
   if sys.platform == 'win32':
+    o['variables']['clang'] = 0
     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')
@@ -1051,6 +1052,7 @@ def check_compiler(o):
     return
 
   ok, is_clang, clang_version, gcc_version = try_check_compiler(CXX, 'c++')
+  o['variables']['clang'] = B(is_clang)
   version_str = ".".join(map(str, clang_version if is_clang else gcc_version))
   print_verbose(f"Detected {'clang ' if is_clang else ''}C++ compiler (CXX={CXX}) version: {version_str}")
   if not ok:

deps/openssl/openssl_common.gypi

@@ -67,7 +67,7 @@
         'TERMIOS',
       ],
       'conditions': [
-        [ 'llvm_version=="0.0"', {
+        [ 'clang==0', {
           'cflags': ['-Wno-old-style-declaration',],
         }],
       ],

deps/zlib/zlib.gyp

@@ -7,7 +7,6 @@
     'ZLIB_ROOT': '.',
     'use_system_zlib%': 0,
     'arm_fpu%': '',
-    'llvm_version%': '0.0',
   },
   'conditions': [
     ['use_system_zlib==0', {
@@ -24,7 +23,7 @@
                 },{
                   'defines': [ 'X86_NOT_WINDOWS' ],
                 }],
-                ['OS!="win" or llvm_version!="0.0"', {
+                ['OS!="win" or clang==1', {
                   'cflags': [ '-mssse3' ],
                   'xcode_settings': {
                     'OTHER_CFLAGS': [ '-mssse3' ],
@@ -65,7 +64,7 @@
           'conditions': [
             ['OS!="ios"', {
               'conditions': [
-                ['OS!="win" and llvm_version=="0.0"', {
+                ['OS!="win" and clang==0', {
                   'cflags': [ '-march=armv8-a+aes+crc' ],
                 }],
                 ['OS=="android"', {
@@ -111,7 +110,7 @@
         #   'target_name': 'zlib_crc32_simd',
         #   'type': 'static_library',
         #   'conditions': [
-        #     ['OS!="win" or llvm_version!="0.0"', {
+        #     ['OS!="win" or clang==1', {
         #       'cflags': [
         #         '-msse4.2',
         #         '-mpclmul',

node.gyp

@@ -504,7 +504,7 @@
           '-Wl,-bnoerrmsg',
         ],
       }],
-      ['OS == "linux" and llvm_version != "0.0"', {
+      ['OS=="linux" and clang==1', {
         'libraries': ['-latomic'],
       }],
     ],

tools/v8_gypfiles/toolchain.gypi

@@ -134,7 +134,7 @@
       '<(V8_ROOT)/include',
     ],
     'conditions': [
-      ['clang', {
+      ['clang==1', {
         'cflags': [ '-Werror', '-Wno-unknown-pragmas' ],
       },{
         'cflags!': [ '-Wall', '-Wextra' ],
@@ -144,7 +144,7 @@
           '-flax-vector-conversions',
         ],
       }],
-      ['clang or OS!="win"', {
+      ['clang==1 or OS!="win"', {
         'cflags': [ '-Wno-invalid-offsetof' ],
         'xcode_settings': {
           'WARNING_CFLAGS': ['-Wno-invalid-offsetof']

tools/v8_gypfiles/v8.gyp

@@ -1879,7 +1879,7 @@
           ['enable_lto=="true"', {
             'cflags_cc': [ '-fno-lto' ],
           }],
-          ['clang or OS!="win"', {
+          ['clang==1 or OS!="win"', {
             'conditions': [
               ['_toolset == "host" and host_arch == "x64" or _toolset == "target" and target_arch=="x64"', {
                 'sources': [