Re:The case against a C alternative
by zozbot234 on Tuesday August 09, 2022 @02:23AM
(#32394797)
Rust does emit bounds and other checks, though. Optimization passes can usually clear some of them away, but you'd need to check the assembly output to be sure.
[ Parent
| on HN ]
Yes, that's "omit".
"Emit" means "to send out", eg "emit a strange noise", "emit radiation".
It is specifically both:
- trying to access an arbitrary element in a slice, the compiler will emit bounds checks (`if index > len: panic()`) to avoid an uncontrolled out-of-bounds memory access — https://godbolt.org/z/cbY5ebzvK (note how if you comment out the assert, the code barely changes, because the compiler is adding an invisible assert of its own)
- if the compiler can infer that `index` will always be less than `len`, then it will omit the bounds check — https://godbolt.org/z/TTashYnjd