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 dfcf529cd501dc890c05425fcf9a33414a45f1a5..38e7b2802f6225ac0e1ff4789b9ff8f4fb04cb79 100644
--- a/common.gypi
+++ b/common.gypi
@@ -71,6 +71,9 @@
     # 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,
@@ -148,6 +151,9 @@
       ['OS=="mac"', {
         'clang%': 1,
       }],
+      ['target_arch == "arm64" or target_arch == "x64"', {
+        'v8_enable_pointer_compression': 1,
+      }],
       ['target_arch in "ppc64 s390x"', {
         'v8_enable_backtrace': 1,
       }],
@@ -378,6 +384,12 @@
           }],
         ],
       }],
+      ['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',
