From 756077867b4901377c11abd5840e040f9e0d135e Mon Sep 17 00:00:00 2001
From: Joyee Cheung <joyeec9h3@gmail.com>
Date: Thu, 19 Dec 2024 04:24:51 +0100
Subject: [PATCH] build: build v8 with -fvisibility=hidden on macOS
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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.

It's only enabled on macOS in this patch as gcc can time out
or run out of memory on some machines in the CI with
-fvisibility=hidden.

PR-URL: https://github.com/nodejs/node/pull/56275
Fixes: https://github.com/nodejs/performance/issues/180
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Daniel Lemire <daniel@lemire.me>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Geoffrey Booth <webadmin@geoffreybooth.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>
---
 tools/v8_gypfiles/v8.gyp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/tools/v8_gypfiles/v8.gyp b/tools/v8_gypfiles/v8.gyp
index 9acad07d966a35..88c1297b9a09ec 100644
--- a/tools/v8_gypfiles/v8.gyp
+++ b/tools/v8_gypfiles/v8.gyp
@@ -41,6 +41,19 @@
         'AdditionalOptions': ['/utf-8']
       }
     },
+    'conditions': [
+      ['OS=="mac"', {
+        # Hide symbols that are not explicitly exported with V8_EXPORT.
+        # TODO(joyeecheung): enable it on other platforms. Currently gcc times out
+        # or run out of memory with -fvisibility=hidden on some machines in the CI.
+        'xcode_settings': {
+          'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES',  # -fvisibility=hidden
+        },
+        'defines': [
+          'BUILDING_V8_SHARED',  # Make V8_EXPORT visible.
+        ],
+      }],
+    ],
   },
   'targets': [
     {