undefined symbol: miri_resolve_frame

[kellerkindt]

I just installed* miri and wanted to try it before adding a stage to the github actions.
But executing cargo +nightly miri test on asn1rs throws the following error:

error: /tmp/cargo-target/debug/deps/libasn1rs_macros-398599e648a8b772.so: undefined symbol: miri_resolve_frame
 --> asn1rs/src/lib.rs:5:1
  |
5 | pub extern crate asn1rs_macros as macros;
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

error: could not compile `asn1rs`

To learn more, run the command again with --verbose.

$ cargo +nightly miri test --version
miri 0.1.0 (12dac5c 2021-03-17)

*like that

$ rustup +nightly component add miri
$ cargo +nightly miri test
I will run `"/home/...../.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo" "install" "xargo"` to install a recent enough xargo. Proceed? [Y/n] y
    Updating crates.io index
  Downloaded xargo v0.3.22
...

[RalfJung]

Okay that is strange, something is trying to actually build code with cfg(miri) -- which cannot work as Miri provides some extern symbols that do not actually exist. Thanks for the report! I won't have time to dig into this before the week-end though.

@hyd-dev any idea what might be going on?

Is miri passing --cfg=miri unconditionally?

miri/src/bin/miri.rs

Line 156 in 7b2e325

args.splice(1..1, miri::MIRI_DEFAULT_ARGS.iter().map(ToString::to_string));

I can't find an if excluding "host" crates, so it seems like all build scripts and proc-macro crates are indeed always built with cfg(miri).

Also, I can confirm cfg(miri) is set for build scripts and proc-macro crates by adding #[cfg(miri)] gated compile_error! to test-cargo-miri/build.rs and test-cargo-miri/subcrate/src/lib.rs.

[RalfJung]

Hm... yeah that's probably bad.^^ MIRI_DEFAULT_ARGS should probably only be set when building "for Miri", not when building for a proc-macro or build.rs.

Adding an if above that args.splice() line that checks --target works: the "undefined symbol" error goes away.

FYI there's an "unsupported operation" error now

test cover_asn_to_rust_macro ... error: unsupported operation: `getcwd` not available when isolation is enabled
   --> /home/hyd-dev/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/sys/unix/os.rs:140:17
    |
140 |             if !libc::getcwd(ptr, buf.capacity()).is_null() {
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `getcwd` not available when isolation is enabled
    |
    = help: pass the flag `-Zmiri-disable-isolation` to disable isolation
            
    = note: inside `std::sys::unix::os::getcwd` at /home/hyd-dev/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/sys/unix/os.rs:140:17
    = note: inside `std::env::current_dir` at /home/hyd-dev/.rustup/toolchains/miri/lib/rustlib/src/rust/library/std/src/env.rs:47:5
note: inside `cover_asn_to_rust_macro` at tests/proc_macro_coverage_hack.rs:18:24
   --> tests/proc_macro_coverage_hack.rs:18:24
    |
18  |         let mut path = env::current_dir().unwrap();
    |                        ^^^^^^^^^^^^^^^^^^
note: inside closure at tests/proc_macro_coverage_hack.rs:14:1
   --> tests/proc_macro_coverage_hack.rs:14:1
    |
14  | / fn cover_asn_to_rust_macro() {
15  | |     walk_dir({
16  | |         // This code doesn't check much. Instead, it does macro expan...
17  | |         // tarpaulin measure code coverage for the macro.
...   |
21  | |     });
22  | | }
    | |_^
    = note: inside `<[closure@tests/proc_macro_coverage_hack.rs:14:1: 22:2] as std::ops::FnOnce<()>>::call_once - shim` at /home/hyd-dev/.rustup/toolchains/miri/lib/rustlib/src/rust/library/core/src/ops/function.rs:227:5
...

Preparing a PR now... 🚧