# Workspace-wide build flags.
#
# aes_armv8: RustCrypto's `aes` 0.8.x enables ARMv8-Crypto hardware AES on aarch64 only behind
# this cfg (x86_64 AES-NI is runtime-detected with no flag; the 0.9 line will make aarch64
# automatic too). Without it every aarch64 client (all Apple + virtually all Android) ran
# SOFTWARE AES on the per-packet decrypt path — measured 2026-07-14 on an M3 Ultra at
# ~240 MiB/s/core (~7 µs per 1.4 KB datagram), which single-handedly capped receive throughput
# at ~1.57 Gbps wire. The cfg still runtime-detects via `cpufeatures`, so a chip without the
# extensions falls back safely.
#
# NOTE: a RUSTFLAGS environment variable OVERRIDES config rustflags entirely — build scripts /
# CI lanes that set RUSTFLAGS for aarch64 targets (cargo-ndk, xcframework) must carry
# `--cfg aes_armv8` themselves.
# polyval_armv8: same story for GCM's other half — `polyval` 0.6.x gates its PMULL (carry-less
# multiply) GHASH path behind this cfg on aarch64. AES alone took open_in_place from 240 to
# ~790 MiB/s on the M3 Ultra; software GHASH still dominated until this flag joined it.
[target.'cfg(target_arch = "aarch64")']
rustflags = ["--cfg", "aes_armv8", "--cfg", "polyval_armv8"]