src: compress embedded icu, builtins, and snapshot

Store the full ICU data file, one-byte builtin sources, and the V8
startup snapshot plus code caches as zstd frames instead of raw
bytes. Decompress each once at startup and keep it for the process
lifetime. On macOS Release, link the executable with -dead_strip,
-x, and -S.

A Release arm64 macOS binary dropped from 140 MB to 59 MB. Intl,
builtins, the snapshot, and code cache behavior are unchanged.
Startup RSS rose by about 40 MB because those blobs are private
heap instead of file-backed pages.

Signed-off-by: Yagiz Nizipli <yagiz@nizipli.com>

Author: anonrig

deps/zstd/zstd.gyp

@@ -100,7 +100,16 @@
       ],
       'sources': [
         '<@(zstd_sources)',
-      ]
-    }
+      ],
+      'toolsets': ['host', 'target'],
+    },
+    {
+      'target_name': 'zstd_compress',
+      'type': 'executable',
+      'toolsets': ['host'],
+      'dependencies': ['zstd#host'],
+      'include_dirs': ['lib'],
+      'sources': ['../../tools/zstd_compress.cc'],
+    },
   ]
 }

node.gyp

@@ -185,6 +185,8 @@
       'src/node_watchdog.cc',
       'src/node_worker.cc',
       'src/node_zlib.cc',
+      'src/zstd_blob.cc',
+      'src/zstd_blob.h',
       'src/path.cc',
       'src/permission/fs_permission.cc',
       'src/permission/permission.cc',
@@ -659,6 +661,23 @@
             'WARNING_CFLAGS': [ '-Werror' ],
           },
         }],
+        # The Release executable force-loads several static libraries, so
+        # unreferenced objects and the symbol table dominate the file.
+        # -dead_strip drops unreferenced .o files, -x drops local symbols,
+        # and -S drops STABS. Debug keeps symbols.
+        ['OS=="mac" or OS=="ios"', {
+          'configurations': {
+            'Release': {
+              'xcode_settings': {
+                'OTHER_LDFLAGS': [
+                  '-Wl,-dead_strip',
+                  '-Wl,-x',
+                  '-Wl,-S',
+                ],
+              },
+            },
+          },
+        }],
         ['node_shared=="true" and OS=="win"', {
           'dependencies': ['generate_node_def'],
           'msvs_settings': {
@@ -1671,6 +1690,9 @@
         [ 'node_shared_libuv=="false"', {
           'dependencies': [ 'deps/uv/uv.gyp:libuv#host' ],
         }],
+        [ 'node_shared_zstd=="false"', {
+          'dependencies': [ 'deps/zstd/zstd.gyp:zstd#host' ],
+        }],
         [ 'OS in "linux mac openharmony"', {
           'defines': ['NODE_JS2C_USE_STRING_LITERALS'],
         }],

node.gypi

@@ -135,6 +135,9 @@
         '<(icu_gyp_path):icuuc',
       ],
       'conditions': [
+        [ 'icu_system!="true"', {
+          'defines': [ 'NODE_HAVE_EMBEDDED_ICU_ZSTD=1' ],
+        }],
         [ 'icu_small=="true"', {
           'defines': [ 'NODE_HAVE_SMALL_ICU=1' ],
           'conditions': [
@@ -144,7 +147,8 @@
               ],
             }],
           ],
-      }]],
+        }],
+      ],
     }],
     [ 'node_use_bundled_v8=="true" and \
        node_enable_v8_vtunejit=="true" and (target_arch=="x64" or \

src/node_i18n.cc

@@ -43,6 +43,10 @@
 #include "node_i18n.h"
 #include "node_external_reference.h"
 #include "simdutf.h"
+#include "zstd_blob.h"
+
+#include <cstdint>
+#include <cstring>
 
 #if defined(NODE_HAVE_I18N_SUPPORT)
 
@@ -68,7 +72,7 @@
 #include <unicode/uversion.h>
 #include "nbytes.h"
 
-#ifdef NODE_HAVE_SMALL_ICU
+#if defined(NODE_HAVE_SMALL_ICU) || defined(NODE_HAVE_EMBEDDED_ICU_ZSTD)
 #include <unicode/udata.h>
 
 /* if this is defined, we have a 'secondary' entry point.
@@ -85,6 +89,38 @@
 extern "C" const char U_DATA_API SMALL_ICUDATA_ENTRY_POINT[];
 #endif
 
+#ifdef NODE_HAVE_EMBEDDED_ICU_ZSTD
+extern "C" const uint8_t node_icu_zstd_dat[];
+
+static uint64_t ReadU64LE(const uint8_t* bytes) {
+  uint64_t value = 0;
+  for (int i = 0; i < 8; i++) {
+    value |= static_cast<uint64_t>(bytes[i]) << (8 * i);
+  }
+  return value;
+}
+
+// Decompress the embedded ICU data file. The returned pointer is aligned and
+// lives for the process lifetime. nullptr on failure, with `error` set.
+static uint8_t* DecompressEmbeddedICU(std::string* error) {
+  const uint8_t* bytes = node_icu_zstd_dat;
+  if (memcmp(bytes, "ICUZ", 4) != 0) {
+    *error = "embedded ICU data header is invalid";
+    return nullptr;
+  }
+  uint64_t raw_size = ReadU64LE(bytes + 4);
+  uint64_t compressed_size = ReadU64LE(bytes + 12);
+  size_t got = 0;
+  uint8_t* data = node::ZstdDecompressAligned(
+      bytes + 20, static_cast<size_t>(compressed_size), &got);
+  if (data == nullptr || got != raw_size) {
+    *error = "failed to decompress embedded ICU data";
+    return nullptr;
+  }
+  return data;
+}
+#endif  // NODE_HAVE_EMBEDDED_ICU_ZSTD
+
 namespace node {
 
 using v8::Context;
@@ -555,7 +591,13 @@ ConverterObject::ConverterObject(
 bool InitializeICUDirectory(const std::string& path, std::string* error) {
   UErrorCode status = U_ZERO_ERROR;
   if (path.empty()) {
-#ifdef NODE_HAVE_SMALL_ICU
+#ifdef NODE_HAVE_EMBEDDED_ICU_ZSTD
+    static uint8_t* icu_data = DecompressEmbeddedICU(error);
+    if (icu_data == nullptr) {
+      return false;
+    }
+    udata_setCommonData(icu_data, &status);
+#elif defined(NODE_HAVE_SMALL_ICU)
     // install the 'small' data.
     udata_setCommonData(&SMALL_ICUDATA_ENTRY_POINT, &status);
 #else  // !NODE_HAVE_SMALL_ICU