From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jeremy Apthorp <nornagon@nornagon.net>
Date: Tue, 10 Dec 2019 15:02:21 -0800
Subject: enable 31 bit smis on 64bit arch and ptr compression

This aligns with the defaults set on the Chromium build. Without this, native
node modules will have different (wrong) ideas about how v8 structs are laid
out in memory on 64-bit machines, and will summarily fail to work.

diff --git a/common.gypi b/common.gypi
index f4d03a2fdfd47a4e6a71c7146d92ce7cbc44993d..d88db157c0e2972c5a7c4f8dacb5a69bff1d9b72 100644
--- a/common.gypi
+++ b/common.gypi
@@ -75,6 +75,9 @@
     # TODO(refack): make v8-perfetto happen
     'v8_use_perfetto': 0,
 
+    'v8_enable_pointer_compression%': 0,
+    'v8_enable_31bit_smis_on_64bit_arch': 1,
+
     ##### end V8 defaults #####
 
     # When building native modules using 'npm install' with the system npm,
@@ -152,6 +155,9 @@
       ['OS=="mac"', {
         'clang%': 1,
       }],
+      ['target_arch == "arm64" or target_arch == "x64"', {
+        'v8_enable_pointer_compression': 1,
+      }],
     ],
   },
 
@@ -375,6 +381,12 @@
           }],
         ],
       }],
+      ['v8_enable_pointer_compression == 1', {
+        'defines': ['V8_COMPRESS_POINTERS'],
+      }],
+      ['v8_enable_pointer_compression == 1 or v8_enable_31bit_smis_on_64bit_arch == 1', {
+        'defines': ['V8_31BIT_SMIS_ON_64BIT_ARCH'],
+      }],
       ['OS == "win"', {
         'defines': [
           'WIN32',
