build: build v8 with -fvisibility=hidden

joyeecheung · joyeecheung · commit 970f1336382d · 2024-12-17T01:01:20.000+01:00
V8 should be built with -fvisibility=hidden, otherwise
the resulting binary would contain unnecessary symbols. In
particular, on macOS, this leads to 5000+ weak symbols
resolved at runtime, leading to a startup regression.

On macOS this also reduces the binary size about ~10MB.
On Linux the size reduction is around 8MB.
diff --git a/tools/v8_gypfiles/v8.gyp b/tools/v8_gypfiles/v8.gyp
@@ -41,6 +41,10 @@
         'AdditionalOptions': ['/utf-8']
       }
     },
+    'cflags': ['-fvisibility=hidden'],
+    'xcode_settings': {
+      'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES',  # -fvisibility=hidden
+    },
   },
   'targets': [
     {

Original file line number	Diff line number	Diff line change
`@@ -41,6 +41,10 @@`
`41`	`41`	`'AdditionalOptions': ['/utf-8']`
`42`	`42`	`}`
`43`	`43`	`},`
	`44`	`+ 'cflags': ['-fvisibility=hidden'],`
	`45`	`+ 'xcode_settings': {`
	`46`	`+ 'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES', # -fvisibility=hidden`
	`47`	`+ },`
`44`	`48`	`},`
`45`	`49`	`'targets': [`
`46`	`50`	`{`