Optimized Fast API calls bypass InvokeFunction and can jump directly to
a symbol after DynamicLibrary::close() unloads its library.
Check the function's closed state in the AArch64 and SysV x64
trampolines before entering the target. If the library is closed,
schedule ERR_FFI_LIBRARY_CLOSED and return without calling the symbol.
Keep the JavaScript guard on platforms without a native trampoline guard
and for signatures that already require argument conversion or
validation. This keeps raw scalar fast calls close to their original
performance on supported platforms.
Signed-off-by: Kamat, Trivikram <16024985+trivikr@users.noreply.github.com>
Assisted-by: codex:gpt-5.6-sol
PR-URL: https://github.com/nodejs/node/pull/64860
Fixes: https://github.com/nodejs/node/issues/64854
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Add fast API trampolines for AArch64 and x86_64.
IsJitMemorySupported() maps an RW page, writes a ret instruction
(0xD65F03C0 AArch64 / 0xC3 x86_64), and mprotects it to RX. A
successful RX transition is treated as the support signal. The page is
deliberately not executed: this check may run during normal operation
(when an FFI function is first created), and executing freshly written
code from a capability probe could SIGSEGV/SIGKILL the process on
systems that block executable memory. The real trampoline emitter
performs the same mprotect at creation time and falls back to libffi
when it is rejected.
The result is computed once via std::call_once and cached for the
lifetime of the process, so concurrent callers never observe a
provisional value.
Wired into CreateFastFFIMetadata() for early nullptr bail-out when
JIT memory is unavailable.
Windows stub returns false (no trampolines yet on this branch).
IsFastCallEligible() validates at parse time whether a signature can
use the fast-call path, covering:
- Return and argument type eligibility (numeric, pointer; no structs)
- Argument count cap (8, matching V8 fast-call limit)
- Per-ABI register pressure limits that mirror the trampoline emitters
(AArch64 and x86_64 SysV). Platforms without an emitter, including
Win64, are reported ineligible.
- Buffer and float args cannot coexist, and buffer args additionally
consume an extra GP register slot on both supported ABIs.
The arg/arg-name lengths are checked before the per-arg loop so a
malformed signature cannot index out of bounds.
Returns nullptr from CreateFastFFIMetadata() for ineligible signatures,
falling back to libffi.
Co-authored-by: Bryan English <bryan@bryanenglish.com>
Signed-off-by: Paolo Insogna <paolo@cowtech.it>
Signed-off-by: Bryan English <bryan@bryanenglish.com>
Assisted-By: OpenAI:GPT-5.5 <openai/gpt-5.5>
PR-URL: https://github.com/nodejs/node/pull/63068
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Bryan English <bryan@bryanenglish.com>
Trivikram Kamat