From aa2a441ce639ff821dd7ad07e3a292a2c3d9ba50 Mon Sep 17 00:00:00 2001
From: Keyhan Vakil <kvakil@sylph.kvakil.me>
Date: Sat, 18 Mar 2023 00:09:37 +0000
Subject: [PATCH] src: use SIMD for snapshot checksum

Snapshot checksum verification uses `v8::Internal::Checksum`, which uses
zlib's adler32 checksum. However it was using the slow version of
adler32 for machines with no SIMD. Let's change it to use the SIMD
version when it is available. Fortunately the necessary incantations
were already included in our _other_ copy of Chromium's zlib in
`deps/zlib/zlib.gyp`, so this is mostly just copying from there.

On a very recent Intel machine, this speeds up the snapshot checksumming
from 870us to 300us (a 570us startup saving), according to:

```bash
for i in {1..100}; do
  ./node --profile-deserialization -e 0
done \
  |& grep 'Verifying snapshot checksum' \
  | awk '{s+=$5} END{print s/NR}'
```

P.S.: maybe we should just disable this entirely via
`--no-verify-snapshot-checksum`? It doesn't feel like a super necessary
protection.
---
 tools/v8_gypfiles/v8.gyp | 133 ++++++++++++++++++++++++++++-----------
 1 file changed, 96 insertions(+), 37 deletions(-)

diff --git a/tools/v8_gypfiles/v8.gyp b/tools/v8_gypfiles/v8.gyp
index 19f224d01b82d8..08bae31cec8a0f 100644
--- a/tools/v8_gypfiles/v8.gyp
+++ b/tools/v8_gypfiles/v8.gyp
@@ -4,6 +4,8 @@
 {
   'variables': {
     'V8_ROOT': '../../deps/v8',
+    'V8_ZLIB_ROOT': '<(V8_ROOT)/third_party/zlib',
+    'arm_fpu%': '',
     'v8_code': 1,
     'v8_random_seed%': 314159265,
     'v8_vector_stores%': 0,
@@ -1884,6 +1886,54 @@
       },
     },  # postmortem-metadata
 
+    {
+      'target_name': 'v8_zlib_adler32_simd',
+      'type': 'static_library',
+      'conditions': [
+        ['target_arch in "ia32 x64" and OS!="ios"', {
+          'defines': [ 'ADLER32_SIMD_SSSE3' ],
+          'conditions': [
+            ['OS=="win"', {
+              'defines': [ 'X86_WINDOWS' ],
+            },{
+              'defines': [ 'X86_NOT_WINDOWS' ],
+            }],
+            ['OS!="win" or llvm_version!="0.0"', {
+              'cflags': [ '-mssse3' ],
+              'xcode_settings': {
+                'OTHER_CFLAGS': [ '-mssse3' ],
+              },
+            }],
+          ],
+        }],
+        ['arm_fpu=="neon"', {
+          'defines': [ 'ADLER32_SIMD_NEON' ],
+        }],
+      ],
+      'include_dirs': [ '<(V8_ZLIB_ROOT)' ],
+      'direct_dependent_settings': {
+        'conditions': [
+          ['target_arch in "ia32 x64" and OS!="ios"', {
+            'defines': [ 'ADLER32_SIMD_SSSE3' ],
+            'conditions': [
+              ['OS=="win"', {
+                'defines': [ 'X86_WINDOWS' ],
+              },{
+                'defines': [ 'X86_NOT_WINDOWS' ],
+              }],
+            ],
+          }],
+          ['arm_fpu=="neon"', {
+            'defines': [ 'ADLER32_SIMD_NEON' ],
+          }],
+        ],
+        'include_dirs': [ '<(V8_ZLIB_ROOT)' ],
+      },
+      'sources': [
+        '<!@pymod_do_main(GN-scraper "<(V8_ZLIB_ROOT)/BUILD.gn" "\\"zlib_adler32_simd\\".*?sources = ")',
+      ],
+    }, # v8_zlib_adler32_simd
+
     {
       'target_name': 'v8_zlib',
       'type': 'static_library',
@@ -1898,52 +1948,61 @@
             }]
           ]
         }],
+        ['target_arch in "ia32 x64" and OS!="ios"', {
+          'dependencies': [
+            'v8_zlib_adler32_simd',
+          ],
+        }],
+        ['arm_fpu=="neon"', {
+          'dependencies': [
+            'v8_zlib_adler32_simd',
+          ],
+        }],
       ],
       'direct_dependent_settings': {
         'include_dirs': [
-          '<(V8_ROOT)/third_party/zlib',
-          '<(V8_ROOT)/third_party/zlib/google',
+          '<(V8_ZLIB_ROOT)',
+          '<(V8_ZLIB_ROOT)/google',
         ],
       },
       'defines': [ 'ZLIB_IMPLEMENTATION' ],
       'include_dirs': [
-        '<(V8_ROOT)/third_party/zlib',
-        '<(V8_ROOT)/third_party/zlib/google',
+        '<(V8_ZLIB_ROOT)',
+        '<(V8_ZLIB_ROOT)/google',
       ],
       'sources': [
-        '<(V8_ROOT)/third_party/zlib/adler32.c',
-        '<(V8_ROOT)/third_party/zlib/chromeconf.h',
-        '<(V8_ROOT)/third_party/zlib/compress.c',
-        '<(V8_ROOT)/third_party/zlib/contrib/optimizations/insert_string.h',
-        '<(V8_ROOT)/third_party/zlib/contrib/optimizations/insert_string.h',
-        '<(V8_ROOT)/third_party/zlib/cpu_features.c',
-        '<(V8_ROOT)/third_party/zlib/cpu_features.h',
-        '<(V8_ROOT)/third_party/zlib/crc32.c',
-        '<(V8_ROOT)/third_party/zlib/crc32.h',
-        '<(V8_ROOT)/third_party/zlib/deflate.c',
-        '<(V8_ROOT)/third_party/zlib/deflate.h',
-        '<(V8_ROOT)/third_party/zlib/gzclose.c',
-        '<(V8_ROOT)/third_party/zlib/gzguts.h',
-        '<(V8_ROOT)/third_party/zlib/gzlib.c',
-        '<(V8_ROOT)/third_party/zlib/gzread.c',
-        '<(V8_ROOT)/third_party/zlib/gzwrite.c',
-        '<(V8_ROOT)/third_party/zlib/infback.c',
-        '<(V8_ROOT)/third_party/zlib/inffast.c',
-        '<(V8_ROOT)/third_party/zlib/inffast.h',
-        '<(V8_ROOT)/third_party/zlib/inffixed.h',
-        '<(V8_ROOT)/third_party/zlib/inflate.c',
-        '<(V8_ROOT)/third_party/zlib/inflate.h',
-        '<(V8_ROOT)/third_party/zlib/inftrees.c',
-        '<(V8_ROOT)/third_party/zlib/inftrees.h',
-        '<(V8_ROOT)/third_party/zlib/trees.c',
-        '<(V8_ROOT)/third_party/zlib/trees.h',
-        '<(V8_ROOT)/third_party/zlib/uncompr.c',
-        '<(V8_ROOT)/third_party/zlib/zconf.h',
-        '<(V8_ROOT)/third_party/zlib/zlib.h',
-        '<(V8_ROOT)/third_party/zlib/zutil.c',
-        '<(V8_ROOT)/third_party/zlib/zutil.h',
-        '<(V8_ROOT)/third_party/zlib/google/compression_utils_portable.cc',
-        '<(V8_ROOT)/third_party/zlib/google/compression_utils_portable.h',
+        '<(V8_ZLIB_ROOT)/chromeconf.h',
+        '<(V8_ZLIB_ROOT)/adler32.c',
+        '<(V8_ZLIB_ROOT)/compress.c',
+        '<(V8_ZLIB_ROOT)/contrib/optimizations/insert_string.h',
+        '<(V8_ZLIB_ROOT)/cpu_features.c',
+        '<(V8_ZLIB_ROOT)/cpu_features.h',
+        '<(V8_ZLIB_ROOT)/crc32.c',
+        '<(V8_ZLIB_ROOT)/crc32.h',
+        '<(V8_ZLIB_ROOT)/deflate.c',
+        '<(V8_ZLIB_ROOT)/deflate.h',
+        '<(V8_ZLIB_ROOT)/gzclose.c',
+        '<(V8_ZLIB_ROOT)/gzguts.h',
+        '<(V8_ZLIB_ROOT)/gzlib.c',
+        '<(V8_ZLIB_ROOT)/gzread.c',
+        '<(V8_ZLIB_ROOT)/gzwrite.c',
+        '<(V8_ZLIB_ROOT)/infback.c',
+        '<(V8_ZLIB_ROOT)/inffast.c',
+        '<(V8_ZLIB_ROOT)/inffast.h',
+        '<(V8_ZLIB_ROOT)/inffixed.h',
+        '<(V8_ZLIB_ROOT)/inflate.c',
+        '<(V8_ZLIB_ROOT)/inflate.h',
+        '<(V8_ZLIB_ROOT)/inftrees.c',
+        '<(V8_ZLIB_ROOT)/inftrees.h',
+        '<(V8_ZLIB_ROOT)/trees.c',
+        '<(V8_ZLIB_ROOT)/trees.h',
+        '<(V8_ZLIB_ROOT)/uncompr.c',
+        '<(V8_ZLIB_ROOT)/zconf.h',
+        '<(V8_ZLIB_ROOT)/zlib.h',
+        '<(V8_ZLIB_ROOT)/zutil.c',
+        '<(V8_ZLIB_ROOT)/zutil.h',
+        '<(V8_ZLIB_ROOT)/google/compression_utils_portable.cc',
+        '<(V8_ZLIB_ROOT)/google/compression_utils_portable.h',
       ],
     },  # v8_zlib
   ],