system_v <-> windows_fastcall mixup

[bjorn3]

error while processing main module ../../target/wasm32-wasi/release/rustc_binary.wasm: Instantiation error: Link error: wasi_unstable/environ_sizes_get: exported function with signature (i64 vmctx, i32, i32) -> i32 system_v incompatible with function import with signature (i64 vmctx, i32, i32) -> i32 windows_fastcall

[bjorn3]

rustc_binary-wasmtime-146-repro.wasm.zip

[bjorn3]

Build from 1c0efd0.

[bjorn3]

Same problem with 2b5be77 (master)

[bjorn3]

This is on Linux, so I have no idea how it tried to use windows_fastcall.

[sunfishcode]

When run that wasm module, I get:

thread 'main' panicked at 'env_logger::init_from_env should not be called after logger initialized: SetLoggerError(())', src/libcore/result.rs:999:5
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
error while processing main module rustc_binary.wasm: Instantiation error: Trap occurred while invoking start function: wasm trap at 0x7fbe5ff9fef2

so something odd is going on.

[kubkon]

I can confirm that I'm getting the same error as @sunfishcode.

[kubkon]

I don't know how related that is, however, I have cloned your repo bjorn3/rust/tree/compile_rustc_for_wasm, I've built it, and managed to run it and print rustc help message OK in wasmtime.

In order to compile rustc, I've followed your instructions in the repo and the wasm32-wasi bit from #144. I've used the following wasmtime invocation when running the binary:

$ wasmtime rustc_binary.wasm -- --help

And got the expected output:

Usage: rustc [OPTIONS] INPUT

Options:
    -h, --help          Display this message
        --cfg SPEC      Configure the compilation environment
    -L [KIND=]PATH      Add a directory to the library search path. The
                        optional KIND can be one of dependency, crate, native,
                        framework or all (the default).
    -l [KIND=]NAME      Link the generated crate(s) to the specified native
                        library NAME. The optional KIND can be one of
                        static, dylib, or framework. If omitted, dylib is
                        assumed.
        --crate-type [bin|lib|rlib|dylib|cdylib|staticlib|proc-macro]
                        Comma separated list of types of crates
                        for the compiler to emit
        --crate-name NAME
                        Specify the name of the crate being built
        --edition 2015|2018
                        Specify which edition of the compiler to use when
                        compiling code.
        --emit [asm|llvm-bc|llvm-ir|obj|metadata|link|dep-info|mir]
                        Comma separated list of types of output for the
                        compiler to emit
        --print [crate-name|file-names|sysroot|cfg|target-list|target-cpus|target-features|relocation-models|code-models|tls-models|target-spec-json|native-static-libs]
                        Comma separated list of compiler information to print
                        on stdout
    -g                  Equivalent to -C debuginfo=2
    -O                  Equivalent to -C opt-level=2
    -o FILENAME         Write output to <filename>
        --out-dir DIR   Write output to compiler-chosen filename in <dir>
        --explain OPT   Provide a detailed explanation of an error message
        --test          Build a test harness
        --target TARGET Target triple for which the code is compiled
    -W, --warn OPT      Set lint warnings
    -A, --allow OPT     Set lint allowed
    -D, --deny OPT      Set lint denied
    -F, --forbid OPT    Set lint forbidden
        --cap-lints LEVEL
                        Set the most restrictive lint level. More restrictive
                        lints are capped at this level
    -C, --codegen OPT[=VALUE]
                        Set a codegen option
    -V, --version       Print version info and exit
    -v, --verbose       Use verbose output

Additional help:
    -C help             Print codegen options
    -W help             Print 'lint' options and default settings
    -Z help             Print unstable compiler options
    --help -v           Print the full set of options rustc accepts

Note that I've used the release version of wasmtime. Also, when simply running

$ wasmtime rustc_binary.wasm

I stumbled upon the following panic!

thread 'main' panicked at 'unsupported', src/libstd/sys/wasi/os.rs:58:5
note: Run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
error while processing main module target/wasm32-wasi/release/rustc_binary.wasm: Instantiation error: Trap occurred while invoking start function: wasm trap at 0x7f1483f9ff7e

The panic! originates from libstd/../split_paths which is not implemented for wasm32-wasi target just yet, so everything as expected ;-)

[bjorn3]

After recompiling wasmtime from scratch it seems to work.