module: use Wasm CJS lexer when available

PR-URL: #35583
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Geoffrey Booth <webmaster@geoffreybooth.com>

Author: guybedford

benchmark/esm/cjs-parse.js

@@ -0,0 +1,40 @@
+'use strict';
+const fs = require('fs');
+const path = require('path');
+const common = require('../common.js');
+const { strictEqual } = require('assert');
+
+const tmpdir = require('../../test/common/tmpdir');
+const benchmarkDirectory =
+  path.resolve(tmpdir.path, 'benchmark-esm-parse');
+
+const bench = common.createBenchmark(main, {
+  n: [1e2]
+});
+
+async function main({ n }) {
+  tmpdir.refresh();
+
+  fs.mkdirSync(benchmarkDirectory);
+
+  let sampleSource = 'try {\n';
+  for (let i = 0; i < 1000; i++) {
+    sampleSource += 'sample.js(() => file = /test/);\n';
+  }
+  sampleSource += '} catch {}\nexports.p = 5;\n';
+
+  for (let i = 0; i < n; i++) {
+    const sampleFile = path.join(benchmarkDirectory, `sample${i}.js`);
+    fs.writeFileSync(sampleFile, sampleSource);
+  }
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    const sampleFile = path.join(benchmarkDirectory, `sample${i}.js`);
+    const m = await import('file:' + sampleFile);
+    strictEqual(m.p, 5);
+  }
+  bench.end(n);
+
+  tmpdir.refresh();
+}

deps/cjs-module-lexer/dist/lexer.js

@@ -56,7 +56,24 @@ const { getOptionValue } = require('internal/options');
 const experimentalImportMetaResolve =
     getOptionValue('--experimental-import-meta-resolve');
 const asyncESM = require('internal/process/esm_loader');
-const cjsParse = require('internal/deps/cjs-module-lexer/lexer');
+
+let cjsParse;
+async function initCJSParse() {
+  if (typeof WebAssembly !== 'undefined') {
+    const { parse, init } =
+        require('internal/deps/cjs-module-lexer/dist/lexer');
+    await init();
+    let exports;
+    try {
+      ({ exports } = parse('exports.a=1'));
+      if (exports.length === 1) {
+        cjsParse = parse;
+        return;
+      }
+    } catch {}
+  }
+  cjsParse = require('internal/deps/cjs-module-lexer/lexer');
+}
 
 const translators = new SafeMap();
 exports.translators = translators;
@@ -167,6 +184,7 @@ translators.set('commonjs', async function commonjsStrategy(url, isMain) {
   if (isWindows)
     filename = StringPrototypeReplace(filename, winSepRegEx, '\\');
 
+  if (!cjsParse) await initCJSParse();
   const { module, exportNames } = cjsPreparseModuleExports(filename);
   const namesWithDefault = exportNames.has('default') ?
     [...exportNames] : ['default', ...exportNames];

deps/cjs-module-lexer/dist/lexer.mjs

@@ -250,6 +250,7 @@
       'deps/acorn-plugins/acorn-private-methods/index.js',
       'deps/acorn-plugins/acorn-static-class-features/index.js',
       'deps/cjs-module-lexer/lexer.js',
+      'deps/cjs-module-lexer/dist/lexer.js',
     ],
     'node_mksnapshot_exec': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)node_mksnapshot<(EXECUTABLE_SUFFIX)',
     'mkcodecache_exec': '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)mkcodecache<(EXECUTABLE_SUFFIX)',

lib/internal/modules/esm/translators.js

@@ -0,0 +1,7 @@
+'use strict';
+
+require('../common');
+
+const runBenchmark = require('../common/benchmark');
+
+runBenchmark('esm', { NODEJS_BENCHMARK_ZERO_ALLOWED: 1 });

node.gyp

@@ -54,7 +54,6 @@ const expectedModules = new Set([
   'NativeModule internal/modules/cjs/helpers',
   'NativeModule internal/modules/cjs/loader',
   'NativeModule internal/modules/esm/create_dynamic_module',
-  'NativeModule internal/deps/cjs-module-lexer/lexer',
   'NativeModule internal/modules/esm/get_format',
   'NativeModule internal/modules/esm/get_source',
   'NativeModule internal/modules/esm/loader',