Malte UblandClaude Opus 5.5 8c8ee28413 Compile bodies with thousands of capture boxes unoptimized
Every box pointer of a captured binding is a value live from its
binding to its last use. A factory whose methods share thousands of
bindings hands LLVM thousands of such ranges, each crossing every call
in between, in the factory and in each method that receives them, and
the inliner, instruction selection and register allocation grow
quadratically: Bun's large-environment AOT program (8,701 captured
bindings) spent about three minutes in native code generation.

A function holding at least 512 capture boxes (the self-hosted compiler's
largest holds under 100) is now emitted `noinline optnone`, and its box
slots are loaded and stored volatile so no IR pass promotes them, which
the native helper's pipeline would otherwise still do for optnone
bodies. Each use reloads its box pointer from the frame. Boxes,
environments and semantics are unchanged; only those bodies' machine
code is unoptimized.

large-environment.ts now compiles in 16 s instead of 227 s (peak RSS
543 MB instead of 777 MB) and runs in the same 0.18 s. Corpus 5973 pins
such a factory's behavior (shared mutation, per-iteration closures, a
nested closure, a forward-captured read in its TDZ), and a harness test
bounds compile-time growth between 500 and 4,000 bindings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-17 19:43:03 -07:00
2026-10-16 10:33:14 -05:00
2026-10-14 17:27:02 -05:00
2026-10-17 13:47:41 -05:00
2026-07-22 18:08:04 -05:00
2026-07-22 18:08:04 -05:00

scriptc

Vercel Labs Experiment npm version: scriptc License: Apache-2.0 npm downloads per month: scriptc

scriptc compiles TypeScript and JavaScript to native executables and WebAssembly. It uses the types checked by the TypeScript compiler to generate machine code, and the output runs without Node.js installed. npm packages your program imports compile along with it. Code scriptc can't compile is reported at build time with a diagnostic and, where available, a rewrite hint.

scriptc is experimental and supports a subset of JavaScript, TypeScript, and Node.js APIs. Run scriptc coverage on an existing program to see how much of it compiles, and see the limitations and Node.js compatibility reference for details.

Installation

Install with Node.js 24 or later and npm:

$ npm install -g scriptc

The installed compiler runs natively on macOS, Linux, and Windows. Node.js is needed only to install it and to run WASI modules with scriptc run. Standalone compiler archives are also available from GitHub Releases.

Building executables requires a linker and the platform SDK or sysroot. See the quickstart for prerequisites and platform support for host requirements, cross-compilation, and WebAssembly.

Build a program

Create hello.ts:

const who = process.argv.length > 2 ? process.argv[2] : "world";
console.log(`hello, ${who}`);

scriptc run compiles the file and runs the result:

$ scriptc run hello.ts
hello, world

scriptc build writes an executable:

$ scriptc build hello.ts -o hello >/dev/null
$ ./hello scriptc
hello, scriptc

These examples use POSIX shell syntax. On Windows, build hello.exe and run it with .\hello.exe.

Use scriptc coverage hello.ts to check what compiles before you build. See coverage reports for details.

Use Node APIs

Supported Node APIs compile to the native runtime. For example, server.ts:

import { createServer } from "node:http";

const server = createServer((req, res) => {
  res.setHeader("content-type", "application/json");
  res.end(JSON.stringify({ path: req.url }));
});

server.listen(8080, () => {
  console.log("listening on http://localhost:8080");
});
$ scriptc build server.ts -o server >/dev/null
$ ./server
listening on http://localhost:8080

Use npm packages

npm packages compile into the executable with your code, so it doesn't read node_modules at runtime.

Create cli.ts:

import pc from "picocolors";

console.log(pc.green("hello from scriptc"));
$ npm install picocolors
$ scriptc build cli.ts -o cli >/dev/null
$ ./cli
hello from scriptc

Package support is partial. See npm dependencies for which packages compile and how to check them.

Documentation

Contributing

See CONTRIBUTING.md for source setup, testing, native artifact builds, and docs development.

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