Quickstart can't build hello world: librustc_codegen_gcc.so not found

[xobs]

I'm trying to build librustc_codegen_gcc.so from this repo (rather than from Rust) to make it easier to upstream patches. However, the Quickstart instructions do not appear to work.

Following the instructions, I've:

1. Copied config.example.toml to config.toml
2. Ran ./y.sh prepare
3. Ran ./y.sh build --sysroot --release

Now I'm trying to run the fourth step:

$ ./y.sh cargo build --manifest-path tests/hello-world/Cargo.toml
[BUILD] build system
    Finished [`release` profile [optimized]](https://doc.rust-lang.org/cargo/reference/profiles.html#default-profiles) target(s) in 0.01s
Using `/home/seancross/Code/rustc_codegen_gcc/build/libgccjit/b794cb99508e7eccd40fa42bb310d5781e09899b` as path for libgccjit
   Compiling hello_world v0.0.0 (/home/seancross/Code/rustc_codegen_gcc/tests/hello-world)
error: couldn't load codegen backend /home/seancross/Code/rustc_codegen_gcc/target/debug/librustc_codegen_gcc.so: cannot open shared object file: No such file or directory

error: could not compile `hello_world` (bin "hello_world") due to 1 previous error
$

It appears to be looking for something under target/debug even though the instructions say to run ./y.sh build --sysroot --release. If I re-run step 3 with ./y.sh build --sysroot without --release, then attempting to build hello-world gives a different error:

$ ./y.sh cargo build --manifest-path tests/hello-world/Cargo.toml
[BUILD] build system
    Finished [`release` profile [optimized]](https://doc.rust-lang.org/cargo/reference/profiles.html#default-profiles) target(s) in 0.00s
Using `/home/seancross/Code/rustc_codegen_gcc/build/libgccjit/b794cb99508e7eccd40fa42bb310d5781e09899b` as path for libgccjit
   Compiling hello_world v0.0.0 (/home/seancross/Code/rustc_codegen_gcc/tests/hello-world)
error[E0463]: can't find crate for `mylib`
 --> src/main.rs:1:5
  |
1 | use mylib::my_func;
  |     ^^^^^ can't find crate

For more information about this error, try `rustc --explain E0463`.
error: could not compile `hello_world` (bin "hello_world") due to 1 previous error
$

[antoyo]

It appears to be looking for something under target/debug even though the instructions say to run ./y.sh build --sysroot --release.

Yeah, I guess the instructions are confusing. It says later to specify the CHANNEL.

If I re-run step 3 with ./y.sh build --sysroot without --release, then attempting to build hello-world gives a different error:

This project uses LTO, so it might be problematic to run. Please try with another project that does not use LTO and tell me if you still have an issue.

[xobs]

I'm able to run rustc directly (which is how I'm writing my testcases), but I'm not able to run the test suite since even CHANNEL=release ./y.sh test --release fails with the error.

What's the correct way to run the test suite?

[antoyo]

I usually do not use --release or CHANNEL=release, so please try dropping both.
If that does not work, please post the complete error.

[xobs]

If I omit the --release flags mentioned in the README.md it does work, yes.

Is t here any way to run just a single test? The whole suite takes a while. That'd be nice to include in the README as well. I'm interested in just running int tests right now, for example.

EDIT: I see from the CI directory I'd want to run ./y.sh test --cargo-tests -- int

[antoyo]

Is there any way to run just a single test?

./y.sh test --help shows the different tests you can run.