vercel-labs/scriptc v0.4.5

on GitHub

0.4.5

Highlights

• Fixes:
  • Release builds read a typed array's length without a header load that could read a freed view.
  • net.Socket write() returns Node's backpressure boolean and fires 'drain'.
  • Super calls in JavaScript method values call the declared base method.
  • Calling a non-function through an asserted callee throws Node's TypeError.
• Faster programs:
  • Exceptions propagate by unwinding from directly called functions on Linux, instead of status checks after every call.
  • Typed-array loops prove their bounds and keep their views disjoint in more cases, including views over shared memory in worker programs; integer loops stay in integers across nested counted loops, pure helper calls, powers of two and byte reads.
  • Lone array callbacks run as loops with their bodies inlined, and row sums run two rows per pass.
  • Number-key maps look keys up on their integer view and write updates through the entry the read found; small number-key maps use a direct index.
  • Strings: base64 decodes eight characters at a time; Buffers fill, swap byte order and decode utf16le a word at a time; readline splits input in one scan; string scans over non-ASCII strings use their UTF-16 units.
  • Untyped code: property caches also cache absent properties, object literal members go through the store caches, calls on plain arrays skip the method ladder, and dynamic values dispose without key-cache walks.
  • JSON parses into discriminated unions, and dynamic values convert into nested unions, in one pass.
  • BigInt division settles quotients from the top limbs, and limb shifts are vectorized.
• Faster builds:
  • Function bodies are emitted on up to eight workers, including in dev builds, and repeated work in LLVM module emission is cut.
  • Linux executables link with lld when the driver finds it, and unchanged executables are reused without selecting the runtime pack.
  • Dev builds reuse their frontend output after edits that keep token positions, and unchanged frontend inputs are checked by file identity before hashing.
  • Lowering fetches only the syntax trees it reads, and the large compiler tables are built on first use.
  • Release builds of the native compiler use a profile collected on the release commit.
  • Type checking can use a tsc-ts server shared by later builds (opt-in).
• Node.js parity:
  • Crypto: RSA key generation lengths, RSA-PSS keys, encrypted private keys, X509Certificate fields and methods, and TLS certificates and tls.Server contexts.
  • zlib: Brotli compression and decompression.
  • Dates are mutable objects with Node's setters and conversions; URL hosts and paths parse as the URL Standard does, including non-ASCII hosts with UTS #46.
  • Math, JSON and Reflect are real objects in JavaScript; objects can inherit from JavaScript class prototypes; typed arrays held as untyped values support named properties and Symbol.species.
  • Error messages: JSON.parse syntax errors use V8's messages and positions; Object.getPrototypeOf of an Error answers Error.prototype.
  • util.inspect of dynamic classes, functions and %o arguments, and Symbol.toStringTag fields and getters, match Node.
• npm packages: more npm and CommonJS dependencies compile statically, including namespace-style packages with guarded declarations and var exports, and untyped Maps, Sets and arrays are typed from their uses.