Drop-in compiler replacement can't find std crate

Question

I am trying to make a drop-in compiler replacement. Here's my source code.

#![feature(rustc_private)]
#![feature(link_args)]

extern crate rustc_driver;

fn main() {
    rustc_driver::set_sigpipe_handler();
    rustc_driver::main();
}

This is actually an exact copy of rustc source code. I built, installed and exported this tool using an environment variable.

cargo install
export RUSTC=tool1    # `tool1` is name of binary

And I tried to build another project example1. Here's source code of example1.

fn main() {}

Build failed with an error.

error[E0463]: can't find crate for `std`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0463`.
error: Could not compile `foo2`.

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

I confirmed example1 got built well with normal cargo. It gets broken only with tool1. (export RUSTC=tool1) If I unset RUSTC, it works again.

It seems I made some fault, but I can't figure out what. How can I make it work?

---

Here're my tool informations.

rustc -V
rustc 1.28.0-nightly (a1d4a9503 2018-05-20)

cargo -V
cargo 1.28.0-nightly (f352115d5 2018-05-15)

Here's full example source code.

Answer 1

Inspecting tool1 shared libraries requirements reveals that the system can not locate Rust shared libraries (I'm on a Linux system so I use ldd):

> ldd /home/adona/.cargo/bin/tool1
    linux-vdso.so.1 =>  (0x00007ffed5938000)
    librustc_driver-aabc67f1ff8e0e97.so => not found
    libstd-46fff00efefae8a8.so => not found
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fa2d6f54000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fa2d7521000)

Set RUSTFLAGS with the -L option if you want build through cargo, for example:

export RUSTFLAGS="-L $HOME/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib"

If you want use tool1 directly from command line you have to configure the linker library path with ldconfig command or with LD_LIBRARY_PATH env variable:

export LD_LIBRARY_PATH=$HOME/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/x86_64-unknown-linux-gnu/lib:$LD_LIBRARY_PATH

Answer 2

Just a guess here, but I think your tool1 is not installed in the same folder as rustc. Note that you may have an executable called rustc in your cargo bin folder alongside your tool1, but this rustc is probably a rustup wrapper that redirects to the real compiler somewhere in your toolchain folder (probably $HOME/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc).

You will need to either install your tool1 inside the toolchain folder or call it with a -L argument pointing to the toolchain libraries (probably $HOME/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib).