Generator performance (babel#13593)

* bench: setup benchmarks

* add charcodes

* perf: use string as buffer backend

baseline 256 empty statements: 3_718 ops/sec ±18.65% (0.269ms)
baseline 512 empty statements: 2_070 ops/sec ±0.96% (0.483ms)
baseline 1024 empty statements: 1_012 ops/sec ±1.76% (0.988ms)
baseline 2048 empty statements: 510 ops/sec ±1.53% (1.96ms)
current 256 empty statements: 3_965 ops/sec ±21.14% (0.252ms)
current 512 empty statements: 2_219 ops/sec ±1.29% (0.451ms)
current 1024 empty statements: 1_089 ops/sec ±1.53% (0.918ms)
current 2048 empty statements: 548 ops/sec ±1.87% (1.824ms)

* perf: add endsWithCharAndNewline

baseline 256 1-length identifiers: 1_947 ops/sec ±25.11% (0.514ms)
baseline 512 1-length identifiers: 1_115 ops/sec ±0.89% (0.897ms)
baseline 1024 1-length identifiers: 537 ops/sec ±1.71% (1.862ms)
baseline 2048 1-length identifiers: 273 ops/sec ±0.57% (3.669ms)
current 256 1-length identifiers: 2_178 ops/sec ±27.17% (0.459ms)
current 512 1-length identifiers: 1_250 ops/sec ±1.19% (0.8ms)
current 1024 1-length identifiers: 622 ops/sec ±0.71% (1.608ms)
current 2048 1-length identifiers: 308 ops/sec ±1.35% (3.251ms)

* perf: avoid one byte string compare

* perf: avoid scaning word for /

* perf: hoist babel type methods

baseline 256 25-length identifiers: 1_869 ops/sec ±29.4% (0.535ms)
baseline 512 25-length identifiers: 1_092 ops/sec ±1.62% (0.916ms)
baseline 1024 25-length identifiers: 537 ops/sec ±1.29% (1.862ms)
baseline 2048 25-length identifiers: 264 ops/sec ±2% (3.793ms)
current 256 25-length identifiers: 2_462 ops/sec ±23.38% (0.406ms)
current 512 25-length identifiers: 1_401 ops/sec ±0.73% (0.714ms)
current 1024 25-length identifiers: 671 ops/sec ±1.55% (1.491ms)
current 2048 25-length identifiers: 332 ops/sec ±1.44% (3.014ms)

* perf: hoist parens methods

baseline 256 1-length identifiers: 2_678 ops/sec ±24.96% (0.373ms)
baseline 512 1-length identifiers: 1_472 ops/sec ±2.33% (0.68ms)
baseline 1024 1-length identifiers: 737 ops/sec ±1.74% (1.357ms)
baseline 2048 1-length identifiers: 371 ops/sec ±0.79% (2.695ms)
current 256 1-length identifiers: 2_633 ops/sec ±32.44% (0.38ms)
current 512 1-length identifiers: 1_676 ops/sec ±1.49% (0.597ms)
current 1024 1-length identifiers: 803 ops/sec ±1.95% (1.246ms)
current 2048 1-length identifiers: 385 ops/sec ±2.22% (2.596ms)

* cleanup unused benchcase

* Update packages/babel-generator/src/buffer.ts

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

* cleanup benchmarks

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

babel.config.js

@@ -179,6 +179,10 @@ module.exports = function (api) {
         plugins: ["babel-plugin-transform-charcodes"],
         assumptions: parserAssumptions,
       },
+      {
+        test: ["packages/babel-generator"].map(normalize),
+        plugins: ["babel-plugin-transform-charcodes"],
+      },
       convertESM && {
         test: [
           "./packages/babel-cli",

packages/babel-generator/benchmark/many-empty-statements/bench.mjs

@@ -0,0 +1,25 @@
+import Benchmark from "benchmark";
+import baseline from "@babel-baseline/generator";
+import current from "../../lib/index.js";
+import parser from "@babel/parser";
+import { report } from "../util.mjs";
+
+const suite = new Benchmark.Suite();
+
+function createInput(length) {
+  return parser.parse(";".repeat(length));
+}
+
+function benchCases(name, implementation, options) {
+  for (const length of [256, 512, 1024, 2048]) {
+    const input = createInput(length);
+    suite.add(`${name} ${length} empty statements`, () => {
+      implementation(input, options);
+    });
+  }
+}
+
+benchCases("baseline", baseline.default);
+benchCases("current", current.default);
+
+suite.on("cycle", report).run();

packages/babel-generator/benchmark/many-identifiers/1-length.mjs

@@ -0,0 +1,25 @@
+import Benchmark from "benchmark";
+import baseline from "@babel-baseline/generator";
+import current from "../../lib/index.js";
+import parser from "@babel/parser";
+import { report } from "../util.mjs";
+
+const suite = new Benchmark.Suite();
+
+function createInput(length) {
+  return parser.parse("a;".repeat(length));
+}
+
+function benchCases(name, implementation, options) {
+  for (const length of [256, 512, 1024, 2048]) {
+    const input = createInput(length);
+    suite.add(`${name} ${length} 1-length identifiers`, () => {
+      implementation(input, options);
+    });
+  }
+}
+
+benchCases("baseline", baseline.default);
+benchCases("current", current.default);
+
+suite.on("cycle", report).run();

packages/babel-generator/benchmark/many-identifiers/25-length.mjs

@@ -0,0 +1,25 @@
+import Benchmark from "benchmark";
+import baseline from "@babel-baseline/generator";
+import current from "../../lib/index.js";
+import parser from "@babel/parser";
+import { report } from "../util.mjs";
+
+const suite = new Benchmark.Suite();
+
+function createInput(length) {
+  return parser.parse("parseMaybeImportAssertion;".repeat(length));
+}
+
+function benchCases(name, implementation, options) {
+  for (const length of [256, 512, 1024, 2048]) {
+    const input = createInput(length);
+    suite.add(`${name} ${length} 25-length identifiers`, () => {
+      implementation(input, options);
+    });
+  }
+}
+
+benchCases("baseline", baseline.default);
+benchCases("current", current.default);
+
+suite.on("cycle", report).run();