←back to thread

Zlib-rs is faster than C

(trifectatech.org)
341 points dochtman | 1 comments | 16 Mar 25 19:35 UTC | HN request time: 0.244s | source
Show context
YZF ◴[16 Mar 25 20:12 UTC] No.43381858[source]▶
I found out I already know Rust:

        unsafe {
            let x_tmp0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x10);
            xmm_crc0 = _mm_clmulepi64_si128(xmm_crc0, crc_fold, 0x01);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, x_tmp0);
            xmm_crc1 = _mm_xor_si128(xmm_crc1, xmm_crc0);
Kidding aside, I thought the purpose of Rust was for safety but the keyword unsafe is sprinkled liberally throughout this library. At what point does it really stop mattering if this is C or Rust?

Presumably with inline assembly both languages can emit what is effectively the same machine code. Is the Rust compiler a better optimizing compiler than C compilers?

replies(30): >>43381895 #>>43381907 #>>43381922 #>>43381925 #>>43381928 #>>43381931 #>>43381934 #>>43381952 #>>43381971 #>>43381985 #>>43382004 #>>43382028 #>>43382110 #>>43382166 #>>43382503 #>>43382805 #>>43382836 #>>43383033 #>>43383096 #>>43383480 #>>43384867 #>>43385039 #>>43385521 #>>43385577 #>>43386151 #>>43386256 #>>43386389 #>>43387043 #>>43388529 #>>43392530 #
gf000 ◴[16 Mar 25 22:18 UTC] No.43383033[source]▶
Rust's borrow checker still checks within unsafe blocks, so unless you are only operating with raw pointers (and not accessing certain references as raw pointers in some small, well-defined blocks) across the whole program it will be significantly more safe than C. Especially given all the other language benefits, like a proper type system that can encode a bunch of invariants, no footguns at every line/initialization/cast, etc.
replies(1): >>43383145 #
1. acdha ◴[16 Mar 25 22:30 UTC] No.43383145[source]▶
Yes. I think it’s easy to underestimate how much the richer language and library ecosystem chip away at the attack surface area. So many past vulnerabilities have been in code which isn’t dealing with low-level interfaces or weird performance optimizations and wouldn’t need to use unsafe. There’ve been so many vulnerabilities in crypto code which weren’t the encryption or hashing algorithms but things like x509/ASN parsing, logging, or the kind of option/error handling logic a Rust programmer would use the type system to validate.