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What in the world do you mean by “non-deterministic”? C compilers, Rust compilers, and assemblers are all deterministic.
by simonask 5mo ago
What in the world do you mean by “non-deterministic”?
C compilers, Rust compilers, and assemblers are all deterministic.
- adgjlsfhk1 5mo ago> C compilers, Rust compilers, and assemblers are all deterministic. Within a version, yes, but not cross version. Different versions of GCC/Clang etc can give you completely different code.
- fguerraz 5mo agoIn cryptography, you want operations to run in constant time, even if it’s wasteful, otherwise an attacker could guess information about the key or plaintext by measuring execution times. Modern compilers are extremely clever and will produce machine code that takes full advantage of modern CPU branch predictors, and reorder instructions to better take advantage of pipelining. This in itself will make the same code run at different speeds depending on the input data. Then there is the whole issue of compiler version roulette. As a developer you have no idea which version of compilers your users and distros will use, and what new and wonderful optimisation they will bring.
- simonask 5mo agoI know that, but none of that makes the compiler output non-deterministic. Determinism does not mean “easy to predict”, it just means “predictable”.