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Daniel Pouzzner
c82cfca8ca
Refactor WC_C_DYNAMIC_FALLBACK architecture to allow per-call alternation between asm and C: * Under WC_C_DYNAMIC_FALLBACK keep the block buffer as the raw big-endian stream and byte-reverse just-in-time inside the C transform, so a given wc_Sha256 / wc_Sha512 instance may switch between the vectorized and pure-C transforms per call without producing a wrong digest. * Add Transform_*_C_from_raw / Transform_*_Len_C_from_raw JIT-reversing adapters; the dispatchers early-out through them on (method == C) || SAVE_VECTOR_REGISTERS2 failure; caller-side method-keyed ByteReverse sites are compiled out under the raw-buffer convention and the final block's length words are written unconditionally big-endian. * Remove the init-time CAN_SAVE_VECTOR_REGISTERS pin from Sha*_SetTransform so the recorded method reflects pure CPU capability (enabling fall-forward, not only fallback). Update the bulk paths to check the transform return and not advance on failure. * The raw-buffer convention is scoped to WC_C_DYNAMIC_FALLBACK specifically -- not to WC_NO_INTERNAL_FUNCTION_POINTERS -- because only the fallback build can change transform mid-object; a plain no-function-pointers build picks one method and keeps it, so it retains the conventional host-endian buffer (no change from incumbent code). * Drop the per-object `.sha_method` member. Method selection is a property of the CPU, not of the hash object, so it becomes a file-scope static in each .c, set once (Sha*_SetTransform() early- returns when already set) and read by every instance. Shrinks both structs. * When WOLFSSL_AESNI is enabled without the rest of USE_INTEL_SPEEDUP, `#undef WC_C_DYNAMIC_FALLBACK` -- AES-NI alone satisfies WC_HAVE_VECTOR_SPEEDUPS but leaves SHA with no vectorized transform to fall back from, and the caller-side gating would otherwise suppress a byte-reversal that is still required.