pipe() into an untyped destination now comes from main's pipeIntoDyn
(stream.unboxDyn); programs with constructor-function streams unbox
through scr_dyn_builtin_stream.c, which also takes those streams, so the
separate dyn.builtinStreamPipe entry point is gone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Bundled npm code (from2, bl, tar-stream, yazl, multistream) builds its
streams as ES5 constructor functions: util.inherits(Ctor, Readable) and
Readable.call(this, opts), with _read/_write/_transform on the
prototype. Readable.call(this) threw SC2020.
A new runtime unit, scr_dyn_builtin_stream.c (feature
dynBuiltinStream), gives the untyped stream constructors their stream
half. Base.call(this, opts) creates a runtime stream over the receiver
and keeps it in a hidden slot; the runtime calls the receiver's
underscore methods through its property lookup; the stream prototypes
carry Node's methods and accessors over the hidden stream; and
EventEmitter's methods register listeners with the runtime stream's
emitter, so runtime events and pipes reach JavaScript listeners with the
receiver as this. _readableState/_writableState are live views.
Stream class values now come from dyn.builtinStreamClass, so only
programs that use them link the stream half. Typed code sees these
objects as their runtime streams: checked casts to the stream classes
take them, readable.pipe() into an untyped destination pipes into them,
and runtime streams crossing into JavaScript answer the constructor
object.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- EventEmitter.defaultMaxListeners on the untyped constructor is Node's
accessor over the default the typed EventEmitter reads: assignments
validate as validateNumber(arg, 'defaultMaxListeners', 0) does, and
getMaxListeners() of emitters without their own limit answers the new
value.
- dyn.builtinInstanceOf and dyn.functionInstanceOf link the
constructor-function unit and the units it calls (dyn-invoke, inspect,
symbol, emitter), so a program whose only use is `this instanceof F`
links.
- The legacy pipe's cleanup runs once: when the destination emits
'close' from end(), the cleanup still queued on the source's 'end'
finds the listeners removed and emit('end') answers true.
Externrefs a guest holds are borrowed pointers. An import's result was
kept only until the outermost call returned, which was before the export
call converted its results to JavaScript, so a result created by an
import was freed before conversion. A table or global slot released the
reference it replaced at once, although the guest may still hold it in a
local after reading the slot. The kept references are now released after
the outermost caller has converted its results (scr_wasm_leave), and a
table or global store during a call keeps the reference it replaces until
then.
Checked memories (explicit bounds checks: sanitized builds, Windows)
grew with realloc, which can move the storage that memory.buffer and its
views alias. They now reserve the address space for their largest size
(mmap on POSIX hosts, VirtualAlloc on Windows) and commit pages as they
grow, so the base never moves. Hosts without address-space reservation
grow in place only until a buffer has been handed out; after that,
growth that would move the storage fails.
Tests: webassembly-externref-lifetimes.mjs (import results through an
export, table and global references replaced by the guest and by
JavaScript), webassembly-memory-growth.test.ts (views written after
growth from JavaScript and from the guest), and translate.test.ts cases
for memargs naming memory 0 explicitly and for local.tee operand types,
which b3bcbaaf7 made consistent with validation. Under SCRIPTC_SAN=1 the
two runtime tests report heap-use-after-free without these changes.
Merges main; internal/compatibility/generated/node-v24-backlog.json is
regenerated with pnpm node-compat.
events.once(emitter, name, { signal }) lowers to events.onceSignal, served
by a new runtime unit (scr_events_once_signal.c, linked only through the
eventsOnceSignal feature). It follows Node 24's lib/events.js: an
undefined signal is the plain form, a value that is not an AbortSignal
rejects with ERR_INVALID_ARG_TYPE, an aborted signal rejects with an
AbortError whose cause is signal.reason, and otherwise a once,
resist-stop-propagation 'abort' listener removes the event and 'error'
listeners and rejects. The event or the error removes the abort listener.
Options other than an object literal with one signal stay refused.
events.once now accepts stream receivers: a stream's runtime-emitted
events use their fixed tuples, and its 'data' and 'keypress' events stay
refused. A NodeJS stream interface slot that holds a stdio handle requests
the general stream representation.
Node's once is an async function that returns the executor's promise, so
its result adopts that promise through a thenable job. The plain form
settled its result two turns early; both forms now settle on Node's turn.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
- matchInferSignature reads a fixed-tuple rest as its positions, so
(...args: [string, number]) needs two arguments, and a positional
any[] pattern parameter matches only when the function's parameter
there accepts an array, as TypeScript's assignability does
(corpus 6398).
- Merge origin/main (200fe8d22); node-v24-backlog.json regenerated.
Under the general stream representation, NodeJS.ReadableStream and
NodeJS.WritableStream compile as the runtime Readable and Writable
classes, so a JavaScript stream object (a constructor-function stream, a
plain object with on/pipe, a stream from bundled npm code) passed through
a TypeScript function typed with them took the checked unwrap and threw.
A program that moves an untyped value into a runtime stream class slot,
or passes an untyped pipe() destination or pipeline stage, now lowers
once more with checked-dynamic stream slots: the two interfaces (and
intersections over them) map to dyn. A native stream rides its typed
capsule and keeps its identity; any other value is the JavaScript object
itself. Member calls dispatch per value: stream.dynNative tests for a
boxed native stream, which takes the ordinary class-method lowering;
other values call their own member through dynInvoke. pipe() into a
JavaScript destination follows Node's Readable.prototype.pipe listener
protocol (stream.pipeDyn). for await and pipeline stages keep the
not-supported error for values that are not native streams.
The runtime code lives in scr_stream_dyn.c behind a new streamDyn
feature, so programs without these libCalls link the same objects.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Bundled npm code (glob, yazl, from2, multistream) subclasses Node's
classes with constructor functions: util.inherits(Ctor, EventEmitter) and
EventEmitter.call(this). util.inherits received an identity token and
threw ERR_INVALID_ARG_TYPE, EventEmitter.call(this) and
EventEmitter.prototype were refused, and `this instanceof Ctor` against
a function was refused.
A new runtime unit (scr_dyn_builtin_class.c, linked by the new
dynBuiltinClass feature) provides EventEmitter, the legacy Stream and
the stream classes as untyped constructor functions with Node's
prototype chain. EventEmitter's prototype ports lib/events.js over the
object's own _events, _eventsCount and _maxListeners properties; Stream
adds the legacy pipe. util.inherits, Base.call/apply(this, ...),
Base.prototype, instanceof on untyped values and JavaScript value reads
of these classes use them. Constructing over a stream class throws
SC2020 where it runs. instanceof against a compiled constructor function
compares its prototype with the value's prototype chain.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Main replaced the runtime-feature scan with a rule table, the executable
unit list with a unit table and the module emission with emit-module.ts:
perfLoop becomes a rule (perf.idleTime, perf.loop*, perf.eld*), a unit
(scr_perf_loop.c) and emit-module's loop-start mark (readsLoopMetrics is
now public). The feature lists take both perfLoop and main's webcrypto.
This branch's lower-exprs.ts hunks move to expressions/property-access.ts
(histogram readings), expressions/binary.ts (`??` with a function
default) and expressions/relational.ts (`in` over class members); the
caughtRead fallback stays in lower-exprs.ts.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The darwin-arm64 runtime pack matrix repeated the common matrix's base
and optional runtime source lists and its variantsFor table, so a new
runtime source needed the same line in both files. The common matrix
now exports BASE_RUNTIME_SOURCES, OPTIONAL_RUNTIME_SOURCES and
variantsFor, and the darwin-arm64 matrix imports them. A comment on the
lists notes that their order is the link order of an executable's
runtime units. Both matrices evaluate to the same objects as before.
Once generic wrappers compile (#1413), the code behind them is reachable.
This closes the general gaps found there:
- performance.eventLoopUtilization() and monitorEventLoopDelay()'s
IntervalHistogram (enable, disable, reset, percentile and the min, max,
mean, stddev, count and exceeds readings), under the fallback
declarations and @types/node. A new runtime unit, scr_perf_loop.c, links
only for programs that read them (the perfLoop feature): an unref'd
sampling interval records into HdrHistogram-shaped buckets, and
utilization measures active time as the main thread's CPU time since
the loop started.
- Catch bindings narrowed by a user type predicate or an assertion read
their members through the checked-dynamic value.
- `??` with a function default of a different signature takes the
optional callback's own function type and adapts the default.
- Optional calls on interface-typed receivers dispatch like the plain
protocol call.
- `any` parameters of function declarations and spelled function types
are checked-dynamic slots, and a generic instantiated at `any` takes
`unknown` there.
- `'key' in err` on Error receivers answers from the declaring subclasses.
- Object.entries over a generic record resolves
`keyof T extends never ? unknown : T[keyof T]` through the binding.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
crypto.subtle.importKey('raw', ...) for HMAC keys, HMAC sign and verify,
and the SHA-1/SHA-2 digests compile through the crypto global, with
CryptoKey values as native handles. scr_webcrypto.c is only the WebCrypto
layer (Web IDL conversion, algorithm normalization, the CryptoKey handle,
promise wrapping and Node's TypeErrors and DOMExceptions) over node:crypto's
digest core and deferred promise queue. It links only into programs that
call these methods (the new webcrypto link feature). Other algorithms, the
jwk format and the other SubtleCrypto methods are SC2020 refusals.
The real jose@6.2.12 HS256 path (SignJWT, jwtVerify) now runs natively. It
also needed four compiler fixes: object patterns of positions and length
over arrays, the Uint8Array base64/hex feature probes, a compile-time
String.fromCharCode.apply, and structuredClone of a parameter whose default
is {}.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
A build now translates every WebAssembly module whose bytes it can see
(W2's discovery) into LLVM IR with a TypeScript translator
(packages/compiler/src/wasm/module.ts, translate.ts) and appends it to the
program module, so the existing LLVM helper optimizes, partitions and
caches it with the program. The program also emits scr_wasm_registry, a
portable table of module descriptors (scr_wasm_abi.h). At run time,
WebAssembly.compile, instantiate, validate, new Module and new Instance
find the translated module by the SHA-256 of its bytes; bytes the build did
not see reject with a CompileError. There is no interpreter and no JIT.
The runtime (scr_wasm.c, link-gated by the new `wasm` feature, handle tags
inside W0's headroom) implements the JavaScript API once, over
descriptors, with Node's semantics and messages: exports (functions,
memories, tables, globals), imports (functions, immutable globals, and
memories, tables and globals other instances export), every trap as
WebAssembly.RuntimeError, the CompileError, LinkError and RuntimeError
classes, compile and instantiate settling on a later turn, and
globalThis.WebAssembly as a value. On 64-bit Linux and macOS, memories sit
in 8 GiB guard reservations and a SIGSEGV/SIGBUS handler turns faults into
traps or stack exhaustion; async fibers get a guard page on first use.
Sanitizer builds and Windows check bounds and the stack explicitly. A
WebAssembly.Module crosses to workers through W0's transfer hook (W4).
W1's refusals become lowerings; the Memory, Table and Global constructors,
Module.imports/exports/customSections and the streaming functions still
refuse with SC2020. The globals: WebAssembly compatibility row moves to
partial.
Evidence: differential corpus programs for the API, TypeScript use and the
codemode worker shape, plus five programs executing about 9,300 commands
of the WebAssembly 2.0 spec suite; all match Node in the plain and
sanitized lanes. quickjs-wasi runs through its own glue, matching Node
(apart from a pre-existing non-wasm fence) and on par with or faster than
V8. The zero-cost gate leaves every non-wasm program byte-identical.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The process.emitWarning replacement and the stdin encoding, string data
listener and stdio 'resize' support changed runtime functions every
program with the dyn-async or events unit links (the shared warning
paths, stdin delivery, the process stream object) and grew their
thread-local state. That code now compiles only into new runtime-pack
variants, SCR_WARNING_REPLACE of scr_async_dyn.c and SCR_STDIO_EXTENDED
of scr_events.c, which the link selects when the program assigns
process.emitWarning or reaches setEncoding, a string 'data' listener or
'resize'. The default objects are byte-identical to before, so other
executables do not change. The development and sanitizer builds pass the
same defines.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Stage S3 of the two-tier design: dynamic-tier functions compute with
jsval, a new IR type holding a 64-bit NaN-boxed word whose numbers,
booleans, undefined and null are immediates, so a number between two
dynamic operators is no longer a heap node.
- IR: the jsval type and js.* builtins (operators and the boundary
conversions fromDyn/toDyn/fromF64/fromBool/fromStr/fromBigInt/toF64).
The jsval pass rewrites dynamic-tier functions after tier assignment:
operator chains, comparisons, number checks and truthiness of operator
results run on jsvals; dyn locals become jsval locals when that saves
boxing; dynamic functions called only from dynamic functions return a
jsval. IR version 17 serializes each function's tier.
- Runtime: scr_js.h and scr_js_value.c behind the dynTier feature
(invariant I3); static runtime units never include scr_js.h.
- Backend: number cases inline (immediate doubles and NUM cells), always
inlined jsval retain/release; 32-bit targets keep boxed cells.
- Interprocedural analyses see jsval conversions as the dyn forms they
replace, so no fact about a static function changes.
Static functions are untouched: typed programs and the self-hosted
compiler's static functions compile to byte-identical LLVM.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
main now has #1286 and later collector changes. Resolved in scr_cycle.c:
the scheduled collection point collects the nursery, then notes the
live-count fall (death rule). Semantic fixes for the new main code:
a full pass's markGray no longer overwrites a young object's `buf` (its
nursery index) with the component number, and a nursery collection
refreshes the death rule's live reading at its end so the young garbage
it frees does not count as deaths outside passes. Formats the runtime
pack matrix test.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
T10 and T12 of the zero-cost compatibility plan, plus the maintainer
decisions:
- Programs that name Temporal type-check against TS 7's temporal lib
(added only for them) and lower to Node 24's answers: typeof is
"undefined", globalThis.Temporal is undefined, other uses throw
ReferenceError at the root read.
- node:v8 is importable; getHeapStatistics answers allocator-derived
figures in Node's shape; other members fence with the by-design reason.
vm's refusal says why.
- node:stream/web exports the web stream globals themselves.
- node:dns/promises and dns.promises: lookup and lookupService as
promises, in the link-gated scr_dns_promises.c unit.
- eval and the Function constructor throw Node's EvalError under
--disallow-code-generation-from-strings; the corpus harness runs the
Node oracle with that flag for `// @disallow-code-generation`.
- graceful-fs is served as node:fs.
Every new lowering replaces a refusal, and the new runtime code links only
when used, so other programs compile to identical bytes (zero-cost gate).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
SCRIPTC_YOUNG_NURSERY=1 at compile time makes an executable allocate
traced, program-owned class instances and records young and link the
collector unit built with SCR_YIN (a runtime pack variant of
scr_cycle.c; libraries never get it). The emitted constructor lists the
object in a per-thread nursery and marks its header: generation
SCR_CYC_YOUNG and its nursery index under the buffered bit, so every
existing release path treats it as a buffered candidate (no call while it
stays alive; scr_cyc_on_dead takes it out of the nursery at its death).
A nursery collection (whenever 4096 young objects are live, at collection
points, before full sweeps and limited passes) counts each young object's
references from other young objects, marks from the objects whose count is
below their reference count (referenced from outside the nursery: stacks,
globals, older objects, runtime structures, FFI, fibers, coroutine
frames), frees what stays unmarked, and gives up the dead set's outgoing
edges after the teardowns. The counts are recomputed at every collection
instead of maintained by a store barrier, so soundness rests only on the
invariants trial deletion already needs. Survivors join trial deletion's
nursery and outside roots become candidates; trial deletion walks young
objects it reaches as nursery-level objects. Per-type admission statistics
send types that do not die in young cycles back to trial deletion for a
while. Publication takes young objects out of the nursery. The RC audit
build checks nursery membership and counts at every collection.
With the flag off, the compiler emits and links exactly what it did
before (249 programs and the self-hosted compiler compared
byte-identical). Measured with the flag on: cg-rings -38%, cg-pairs -27%,
the runtime suite geomean -0.3% (published-graphs +3.4%), the self-hosted
compiler neutral; shapes whose cycles go through arrays or closures
(phase 2) pay without gaining.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
ThreadSlots<K, V> holds one value per key and thread, like a WeakMap that
each thread has its own copy of; under Node.js it is a WeakMap per name
and thread. Setting a value never writes the key, so values can be set on
published keys.
Classes used as keys carry a 32-bit slot word after their header words,
assigned on the first set for a key (with a compare-and-swap for a
published key) and never reused. Each family has one block per thread
that maps slot indices to values through pages of 1024 entries. get and
has are inline reads of the slot word, the page and the entry; set and
delete call scr_slots.c, which holds one reference to each value. A key
class's free paths release the key's values, and thread exit releases the
rest.
fs.cpSync, fs.cp and fs/promises cp compile with every option:
dereference, errorOnExist, filter, force, mode, preserveTimestamps,
recursive and verbatimSymlinks. They follow Node's two implementations.
cpSync follows cp-sync.js over the fs binding: copy errors are plain
Errors with a code, std::error_code failures throw an ErrnoException,
and links inside a copied directory point at their canonical targets.
fs.cp and fs/promises cp follow cp.js, whose copy errors are
SystemErrors with code, info, errno, syscall and path.
Options and paths validate in Node's order with Node's errors. filter
runs for the top-level paths and each entry in Node's order; an async
filter must return a promise that is already settled, and a pending one
throws SC2020. The callback and promise forms complete the copy before
the callback runs or the promise settles. Windows builds throw SC2020.
The copy lives in the new scr_fs_cp.c. Directory walks keep their frames
on the heap, so deep trees also copy on a fiber's stack. File contents
copy with sendfile on Linux, and COPYFILE_FICLONE uses FICLONE
where it exists. ScrError gains the SystemError context and the
ErrnoException key order, with matching fields in the compiler's Error
layout. The stored fs.cp callback uses the same implementation.
Corpus 5567-5571 cover the sync, callback and promise forms, errors,
symlinks and 1500-level trees.
Release executables now import small runtime functions from runtime
bitcode, as speed executables do, so LLVM can inline them into program
code. Release units keep the runtime compiler's own objects, unchanged,
and additionally ship the bitcode of the same compilation reduced by the
helper's prune-import. Their unit-local symbols stay local, so only
bodies that need none of them can be imported, which keeps the import
small: about 1.3 MB per program.
Only unsanitized programs small enough for one codegen partition import.
Every partition reads the bitcode again; on the Effect fixtures (64
partitions) import cost +2..18% compile time and +4.3..4.9% size, so
partitioned release builds stay exactly as before. Speed is unchanged.
Measured against main in Linux Vercel Sandboxes, same-VM interleaved
medians (bench-runtime --layouts=4 --runs=16), on two VMs:
- bench-runtime (31 workloads): -1.3% (8 faster, 0 slower) and -1.0%
(1 slower, typed-array-scan-workers +3.2%); size +0.0%
- js-compiled suite (22 programs): -2.2% and -1.8%; size -0.1%
- cold builds of all 53 programs, interleaved: +3.1%; helper time per
build +40..235 ms
- Effect fixtures: byte-identical to main
fs.createReadStream, fs.createWriteStream and FileHandle
createReadStream, createWriteStream and readLines return runtime
Readable and Writable streams (scr_fs_stream.c), as do new fs.ReadStream
and new fs.WriteStream in JavaScript sources. They follow
lib/internal/fs/streams.js on the stream engine:
- _construct opens the file, then emits 'open' (with the fd) and
'ready'; _read reads up to end; _write retries short writes as
writeAll does; _destroy waits for I/O in flight, then closes (with
fsync first for the flush option). Every open, read, write, fsync and
close runs on the shared worker pool.
- Options are checked in Node's order: getOptions, options.fd or the
path, start, end, then highWaterMark, encoding, emitClose and
autoClose. flags and mode are checked when the file opens, so their
errors arrive as 'error' events.
- bytesRead, bytesWritten, pending, path and close(cb) compile, also
through untyped values (close() there).
A FileHandle stream holds a reference on the handle; closing the stream
releases it and closes the handle unless autoClose is false.
FileHandle.close() follows Node's reference count: it waits for the
streams over the handle and runs their close(). readLines is a readline
Interface over createReadStream with crlfDelay: Infinity.
The stream engine gains Node's _construct (reads, buffered writes,
finish and _destroy wait for construction; destroy errors combine with
aggregateTwoErrors) and _writev, both internal. Writable.destroy() now
runs the buffered write callbacks and end() callbacks (errorBuffer),
which it dropped before. highWaterMark in a dynamic options record is
checked as getHighWaterMark does, and for await over a constructing
stream waits for construction.
Numeric flags, the fs, signal and windowsHandle options, non-UTF-8
write encodings, option functions that replace the file implementation,
and instanceof fs.ReadStream/WriteStream are refused.
Corpus 5546, 5547 and 5554 cover both lanes against Node 24.22.
@scriptc/experimental exports InternTable<K, V>: a named table that every
thread of a scriptc program shares and that each thread has its own copy
of under Node.js. Keys are strings or numbers with Map equality; values are
published (@scriptc/threads) when stored, and the first stored value of a
key is kept. Members are get, has, size, getOrInsert and
getOrInsertComputed.
The runtime table (scr_itable.c) splits each table into 64 segments.
Lookups take no lock and do not write; inserts take a segment's spin lock
for a probe and a few stores, and callbacks run without a lock. Number
tables keep keys and values in the index; string tables keep entries in
segment-owned chunks behind tagged slots. Replaced indexes are kept.
The compiler lowers the class to a synthetic class with one f64 handle
field and five intrinsics, with interned helpers per member and type and
an in-place lowering of getOrInsertComputed that creates a function
expression callback only on a miss. Stored values go through the publish
intrinsic, so their types get the write guard. scriptc refuses names that
are not string literals, one name opened with different type arguments,
and key or value types a table cannot store.
scr_publish walks small graphs in inline buffers and reads
SCRIPTC_PUBLISH_TRACE once, instead of allocating and calling getenv on
every call.
Chris Tate