sea: support code cache for ESM entrypoint in SEA

The initial support for ESM entrypoint in SEA didn't support
code cache. This patch implements that by following a path
similar to how code cache in CJS SEA entrypoint is supported:
at build time we generate the code cache from C++ and put it
into the sea blob, and at runtime we consume it via a special
case in compilation routines - for CJS this was
CompileFunctionForCJSLoader, in the case of SourceTextModule,
it's in Module::New.

doc/api/single-executable-applications.md

@@ -395,8 +395,7 @@ The accepted values are:
 
 If the `mainFormat` field is not specified, it defaults to `"commonjs"`.
 
-Currently, `"mainFormat": "module"` cannot be used together with `"useSnapshot"`
-or `"useCodeCache"`.
+Currently, `"mainFormat": "module"` cannot be used together with `"useSnapshot"`.
 
 ### Module loading in the injected main script
 

src/module_wrap.cc

@@ -1,12 +1,14 @@
 #include "module_wrap.h"
 
+#include "debug_utils-inl.h"
 #include "env.h"
 #include "memory_tracker-inl.h"
 #include "node_contextify.h"
 #include "node_errors.h"
 #include "node_external_reference.h"
 #include "node_internals.h"
 #include "node_process-inl.h"
+#include "node_sea.h"
 #include "node_url.h"
 #include "node_watchdog.h"
 #include "util-inl.h"
@@ -365,6 +367,20 @@ void ModuleWrap::New(const FunctionCallbackInfo<Value>& args) {
             new ScriptCompiler::CachedData(data + cached_data_buf->ByteOffset(),
                                            cached_data_buf->ByteLength());
       }
+#ifndef DISABLE_SINGLE_EXECUTABLE_APPLICATION
+      // For embedder ESM in a SEA, use the bundled code cache if available.
+      if (id_symbol == realm->isolate_data()->embedder_module_hdo() &&
+          sea::IsSingleExecutable()) {
+        sea::SeaResource sea = sea::FindSingleExecutableResource();
+        if (sea.use_code_cache()) {
+          std::string_view data = sea.code_cache.value();
+          user_cached_data = new ScriptCompiler::CachedData(
+              reinterpret_cast<const uint8_t*>(data.data()),
+              static_cast<int>(data.size()),
+              ScriptCompiler::CachedData::BufferNotOwned);
+        }
+      }
+#endif  // !DISABLE_SINGLE_EXECUTABLE_APPLICATION
       Local<String> source_text = args[2].As<String>();
 
       bool cache_rejected = false;
@@ -389,12 +405,26 @@ void ModuleWrap::New(const FunctionCallbackInfo<Value>& args) {
         return;
       }
 
-      if (user_cached_data.has_value() && user_cached_data.value() != nullptr &&
-          cache_rejected) {
-        THROW_ERR_VM_MODULE_CACHED_DATA_REJECTED(
-            realm, "cachedData buffer was rejected");
-        try_catch.ReThrow();
-        return;
+      if (user_cached_data.has_value() && user_cached_data.value() != nullptr) {
+#ifndef DISABLE_SINGLE_EXECUTABLE_APPLICATION
+        if (id_symbol == realm->isolate_data()->embedder_module_hdo() &&
+            sea::IsSingleExecutable()) {
+          if (cache_rejected) {
+            per_process::Debug(DebugCategory::SEA,
+                               "SEA module code cache rejected\n");
+            ProcessEmitWarningSync(realm->env(), "Code cache data rejected.");
+          } else {
+            per_process::Debug(DebugCategory::SEA,
+                               "SEA module code cache accepted\n");
+          }
+        } else  // NOLINT(readability/braces)
+#endif          // !DISABLE_SINGLE_EXECUTABLE_APPLICATION
+          if (cache_rejected) {
+            THROW_ERR_VM_MODULE_CACHED_DATA_REJECTED(
+                realm, "cachedData buffer was rejected");
+            try_catch.ReThrow();
+            return;
+          }
       }
 
       if (that->Set(context,

src/node_sea.cc

@@ -24,18 +24,21 @@ using v8::Array;
 using v8::ArrayBuffer;
 using v8::BackingStore;
 using v8::Context;
+using v8::Data;
 using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::HandleScope;
 using v8::Isolate;
 using v8::Local;
 using v8::LocalVector;
 using v8::MaybeLocal;
+using v8::Module;
 using v8::NewStringType;
 using v8::Object;
 using v8::ScriptCompiler;
 using v8::ScriptOrigin;
 using v8::String;
+using v8::UnboundModuleScript;
 using v8::Value;
 
 namespace node {
@@ -542,7 +545,7 @@ std::optional<SeaConfig> ParseSingleExecutableConfig(
             "\"useCodeCache\" is redundant when \"useSnapshot\" is true\n");
   }
 
-  // TODO(joyeecheung): support ESM with useSnapshot and useCodeCache.
+  // TODO(joyeecheung): support ESM with useSnapshot.
   if (result.main_format == ModuleFormat::kModule &&
       static_cast<bool>(result.flags & SeaFlags::kUseSnapshot)) {
     FPrintF(stderr,
@@ -551,14 +554,6 @@ std::optional<SeaConfig> ParseSingleExecutableConfig(
     return std::nullopt;
   }
 
-  if (result.main_format == ModuleFormat::kModule &&
-      static_cast<bool>(result.flags & SeaFlags::kUseCodeCache)) {
-    FPrintF(stderr,
-            "\"mainFormat\": \"module\" is not supported when "
-            "\"useCodeCache\" is true\n");
-    return std::nullopt;
-  }
-
   if (result.main_path.empty()) {
     FPrintF(stderr,
             "\"main\" field of %s is not a non-empty string\n",
@@ -616,7 +611,8 @@ ExitCode GenerateSnapshotForSEA(const SeaConfig& config,
 }
 
 std::optional<std::string> GenerateCodeCache(std::string_view main_path,
-                                             std::string_view main_script) {
+                                             std::string_view main_script,
+                                             ModuleFormat format) {
   RAIIIsolate raii_isolate(SnapshotBuilder::GetEmbeddedSnapshotData());
   Isolate* isolate = raii_isolate.get();
 
@@ -647,34 +643,62 @@ std::optional<std::string> GenerateCodeCache(std::string_view main_path,
     return std::nullopt;
   }
 
-  LocalVector<String> parameters(
-      isolate,
-      {
-          FIXED_ONE_BYTE_STRING(isolate, "exports"),
-          FIXED_ONE_BYTE_STRING(isolate, "require"),
-          FIXED_ONE_BYTE_STRING(isolate, "module"),
-          FIXED_ONE_BYTE_STRING(isolate, "__filename"),
-          FIXED_ONE_BYTE_STRING(isolate, "__dirname"),
-      });
-  ScriptOrigin script_origin(filename, 0, 0, true);
-  ScriptCompiler::Source script_source(content, script_origin);
-  MaybeLocal<Function> maybe_fn =
-      ScriptCompiler::CompileFunction(context,
-                                      &script_source,
-                                      parameters.size(),
-                                      parameters.data(),
-                                      0,
-                                      nullptr);
-  Local<Function> fn;
-  if (!maybe_fn.ToLocal(&fn)) {
-    return std::nullopt;
+  std::unique_ptr<ScriptCompiler::CachedData> cache;
+
+  if (format == ModuleFormat::kModule) {
+    // Using empty host defined options is fine as it is not part of the cache
+    // key and will be reset after deserialization.
+    ScriptOrigin origin(filename,
+                        0,               // line offset
+                        0,               // column offset
+                        true,            // is cross origin
+                        -1,              // script id
+                        Local<Value>(),  // source map URL
+                        false,           // is opaque
+                        false,           // is WASM
+                        true,            // is ES Module
+                        Local<Data>());  // host defined options
+    ScriptCompiler::Source source(content, origin);
+    Local<Module> module;
+    if (!ScriptCompiler::CompileModule(isolate, &source).ToLocal(&module)) {
+      return std::nullopt;
+    }
+    Local<UnboundModuleScript> unbound = module->GetUnboundModuleScript();
+    cache.reset(ScriptCompiler::CreateCodeCache(unbound));
+  } else {
+    // TODO(RaisinTen): Using the V8 code cache prevents us from using
+    // `import()` in the SEA code. Support it. Refs:
+    // https://github.com/nodejs/node/pull/48191#discussion_r1213271430
+    // TODO(joyeecheung): this likely has been fixed by
+    // https://chromium-review.googlesource.com/c/v8/v8/+/5401780 - add a test
+    // and update docs.
+    LocalVector<String> parameters(
+        isolate,
+        {
+            FIXED_ONE_BYTE_STRING(isolate, "exports"),
+            FIXED_ONE_BYTE_STRING(isolate, "require"),
+            FIXED_ONE_BYTE_STRING(isolate, "module"),
+            FIXED_ONE_BYTE_STRING(isolate, "__filename"),
+            FIXED_ONE_BYTE_STRING(isolate, "__dirname"),
+        });
+    ScriptOrigin script_origin(filename, 0, 0, true);
+    ScriptCompiler::Source script_source(content, script_origin);
+    Local<Function> fn;
+    if (!ScriptCompiler::CompileFunction(context,
+                                         &script_source,
+                                         parameters.size(),
+                                         parameters.data(),
+                                         0,
+                                         nullptr)
+             .ToLocal(&fn)) {
+      return std::nullopt;
+    }
+    cache.reset(ScriptCompiler::CreateCodeCacheForFunction(fn));
   }
 
-  // TODO(RaisinTen): Using the V8 code cache prevents us from using `import()`
-  // in the SEA code. Support it.
-  // Refs: https://github.com/nodejs/node/pull/48191#discussion_r1213271430
-  std::unique_ptr<ScriptCompiler::CachedData> cache{
-      ScriptCompiler::CreateCodeCacheForFunction(fn)};
+  if (!cache) {
+    return std::nullopt;
+  }
   std::string code_cache(cache->data, cache->data + cache->length);
   return code_cache;
 }
@@ -728,7 +752,7 @@ ExitCode GenerateSingleExecutableBlob(
   std::string code_cache;
   if (static_cast<bool>(config.flags & SeaFlags::kUseCodeCache)) {
     std::optional<std::string> optional_code_cache =
-        GenerateCodeCache(config.main_path, main_script);
+        GenerateCodeCache(config.main_path, main_script, config.main_format);
     if (!optional_code_cache.has_value()) {
       FPrintF(stderr, "Cannot generate V8 code cache\n");
       return ExitCode::kGenericUserError;

test/fixtures/sea/esm-code-cache/sea-config.json

@@ -0,0 +1,7 @@
+{
+  "main": "sea.mjs",
+  "output": "sea",
+  "mainFormat": "module",
+  "useCodeCache": true,
+  "disableExperimentalSEAWarning": true
+}

test/fixtures/sea/esm-code-cache/sea.mjs

@@ -0,0 +1,20 @@
+import assert from 'node:assert';
+import { createRequire } from 'node:module';
+import { pathToFileURL } from 'node:url';
+import { dirname } from 'node:path';
+
+// Test createRequire with process.execPath.
+const assert2 = createRequire(process.execPath)('node:assert');
+assert.strictEqual(assert2.strict, assert.strict);
+
+// Test import.meta properties.
+assert.strictEqual(import.meta.url, pathToFileURL(process.execPath).href);
+assert.strictEqual(import.meta.filename, process.execPath);
+assert.strictEqual(import.meta.dirname, dirname(process.execPath));
+assert.strictEqual(import.meta.main, true);
+
+// Test import() with a built-in module.
+const { strict } = await import('node:assert');
+assert.strictEqual(strict, assert.strict);
+
+console.log('ESM SEA with code cache executed successfully');

test/sea/test-single-executable-application-esm-code-cache.js

@@ -0,0 +1,34 @@
+'use strict';
+
+// This tests the creation of a single executable application with an ESM
+// entry point using "mainFormat": "module" and "useCodeCache": true.
+
+require('../common');
+
+const {
+  buildSEA,
+  skipIfBuildSEAIsNotSupported,
+} = require('../common/sea');
+
+skipIfBuildSEAIsNotSupported();
+
+const tmpdir = require('../common/tmpdir');
+const fixtures = require('../common/fixtures');
+const { spawnSyncAndExitWithoutError } = require('../common/child_process');
+
+tmpdir.refresh();
+
+const outputFile = buildSEA(fixtures.path('sea', 'esm-code-cache'));
+
+spawnSyncAndExitWithoutError(
+  outputFile,
+  {
+    env: {
+      NODE_DEBUG_NATIVE: 'SEA',
+      ...process.env,
+    },
+  },
+  {
+    stdout: /ESM SEA with code cache executed successfully/,
+    stderr: /SEA module code cache accepted/,
+  });