miri: can't call foreign functions from cmath (libm)

I just tried cargo miri test on the various num crates. I got pretty far, but I was stopped by errors on foreign function calls from std::sys::cmath, which come from libm on unix platforms. For example:

num-complex:

error[E0080]: constant evaluation error: can't call foreign function: hypot
   --> /home/jistone/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/f64.rs:533:18
    |
533 |         unsafe { cmath::hypot(self, other) }
    |                  ^^^^^^^^^^^^^^^^^^^^^^^^^ can't call foreign function: hypot
    |

num-integer:

   --> /home/jistone/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd/f64.rs:513:18
    |
513 |         unsafe { cmath::cbrt(self) }
    |                  ^^^^^^^^^^^^^^^^^ can't call foreign function: cbrt
    |

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 17 (17 by maintainers)

Most upvoted comments

FWIW, here’s the error I get with num-complex when I try to add a seed for hashing:

Ah, I’ve seen that before. Please wait until https://github.com/rust-lang/miri/pull/830 lands, Miri currently does not fully work when a seed is set. That PR should fix your problem, in fact it adds it specifically as a test case.

RalfJung on Jul 9, 2019

I am a num author, so yes, this is something I would like in CI.

cuviper on Jun 4, 2019

Yeah, I have a toolchain stage2 pointing to build/x86_64-unknown-linux-gnu/stage2. Then I ./x.py build src/rustc in the rustc dir, switch to the Miri dir, rustup override set stage2 and finally ./miri install.

Also see the relevant section in the Miri README.

RalfJung on Jun 4, 2019