wasmtime / Issue #1440 How to make: wasm calls wasm · git-wasmtime

Stream: git-wasmtime

Topic: wasmtime / Issue #1440 How to make: wasm calls wasm

Wasmtime GitHub notifications bot (Mar 31 2020 at 08:32):

aleksmelnikov opened Issue #1440:

Hi,
please advise me how to make:

I created a simple library crate:

$cat a/src/lib.rs

#[no_mangle]
pub extern "C" fn funca() {
   println!("funca");
}

#[no_mangle]
pub extern "C" fn _start() {
}

And compiled it:
cargo build --manifest-path=a/Cargo.toml --target=wasm32-wasi

I can invoke funca:

$wasmtime run --invoke funca a/target/wasm32-wasi/debug/a.wasm
funca

I created a simple binary crate:

$cat d/src/main.rs

use anyhow::Result;
use wasmtime::*;
use wasmtime_wasi::{Wasi, WasiCtx};

fn main() -> Result<()> {
    let store = Store::default();
    let module = Module::from_file(&store, "/at/rust/wasmer/a/target/wasm32-wasi/debug/a.wasm")?;
    let wasi = Wasi::new(&store, WasiCtx::new(std::env::args())?);
    let mut imports = Vec::new();
    for import in module.imports() {
        if import.module() == "wasi_snapshot_preview1" {
            if let Some(export) = wasi.get_export(import.name()) {
                imports.push(Extern::from(export.clone()));
                continue;
            }
        }
        panic!(
            "couldn't find import for `{}::{}`",
            import.module(),
            import.name()
        );
    }

    let instance = Instance::new(&module, &imports)?;

    // 1
/*
    let start = instance
        .get_export("_start")
        .and_then(|e| e.func())
        .unwrap();
    let start = start.get0::<()>()?;
    start()?;
*/
    // 2
    let funca = instance
        .get_export("funca")
        .expect("export named `answer` not found")
        .func()
        .expect("export `answer` was not a function");
    let funca = funca.get0::<()>()?;
    funca()?;

    Ok(())
}

And compiled it:
cargo build --manifest-path=d/Cargo.toml

I ran it and got:

$cargo run --manifest-path=d/Cargo.toml
funca

Good! Now I want change d from binary crate to library crate. So, I want wasm lib calls wasm lib.
The first, I tried to compile my bin crate with --target=wasm32-wasi to get wasm and failed:

$cargo +nightly build --manifest-path=d/Cargo.toml --target=wasm32-wasi

   Compiling wat v1.0.13
   Compiling jobserver v0.1.21
   Compiling generic-array v0.12.3
   Compiling region v2.1.2
   Compiling gimli v0.20.0
error[E0425]: cannot find function `lock` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lock.rs:30:7
   |
30 |   os::lock(
   |       ^^^^ not found in `os`
   |
help: possible candidate is found in another module, you can import it into scope
   |
1  | use lock::lock;
   |

error[E0425]: cannot find function `unlock` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lock.rs:58:7
   |
58 |   os::unlock(
   |       ^^^^^^ not found in `os`
   |
help: possible candidate is found in another module, you can import it into scope
   |
1  | use lock::unlock;
   |

error[E0425]: cannot find function `page_size` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/page.rs:16:39
   |
16 |     INIT.call_once(|| PAGE_SIZE = os::page_size());
   |                                       ^^^^^^^^^ not found in `os`

error[E0425]: cannot find function `set_protection` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/protect.rs:40:7
   |
40 |   os::set_protection(
   |       ^^^^^^^^^^^^^^ not found in `os`

error[E0425]: cannot find function `get_region` in module `os`
   --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lib.rs:133:7
    |
133 |   os::get_region(page::floor(address as usize) as *const u8)
    |       ^^^^^^^^^^ not found in `os`

error: aborting due to 5 previous errors

For more information about this error, try `rustc --explain E0425`.
error: could not compile `region`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

So, I think doesn't region support --target=wasm32-wasi? How to create wasm calls wasm?

Wasmtime GitHub notifications bot (Mar 31 2020 at 11:11):

bjorn3 commented on Issue #1440:

You can't compile wasmtime for wasm, as wasm doesn't allow any JIT compilation. What do you want to actually do?

Wasmtime GitHub notifications bot (Mar 31 2020 at 14:19):

aleksmelnikov commented on Issue #1440:

@bjorn3 , ok. Thank you for the notes about wasmtime. I see my mistake.

Wasmtime GitHub notifications bot (Mar 31 2020 at 14:23):

aleksmelnikov closed Issue #1440:

Hi,
please advise me how to make:

I created a simple library crate:

$cat a/src/lib.rs

#[no_mangle]
pub extern "C" fn funca() {
   println!("funca");
}

#[no_mangle]
pub extern "C" fn _start() {
}

And compiled it:
cargo build --manifest-path=a/Cargo.toml --target=wasm32-wasi

I can invoke funca:

$wasmtime run --invoke funca a/target/wasm32-wasi/debug/a.wasm
funca

I created a simple binary crate:

$cat d/src/main.rs

use anyhow::Result;
use wasmtime::*;
use wasmtime_wasi::{Wasi, WasiCtx};

fn main() -> Result<()> {
    let store = Store::default();
    let module = Module::from_file(&store, "/at/rust/wasmer/a/target/wasm32-wasi/debug/a.wasm")?;
    let wasi = Wasi::new(&store, WasiCtx::new(std::env::args())?);
    let mut imports = Vec::new();
    for import in module.imports() {
        if import.module() == "wasi_snapshot_preview1" {
            if let Some(export) = wasi.get_export(import.name()) {
                imports.push(Extern::from(export.clone()));
                continue;
            }
        }
        panic!(
            "couldn't find import for `{}::{}`",
            import.module(),
            import.name()
        );
    }

    let instance = Instance::new(&module, &imports)?;

    // 1
/*
    let start = instance
        .get_export("_start")
        .and_then(|e| e.func())
        .unwrap();
    let start = start.get0::<()>()?;
    start()?;
*/
    // 2
    let funca = instance
        .get_export("funca")
        .expect("export named `answer` not found")
        .func()
        .expect("export `answer` was not a function");
    let funca = funca.get0::<()>()?;
    funca()?;

    Ok(())
}

And compiled it:
cargo build --manifest-path=d/Cargo.toml

I ran it and got:

$cargo run --manifest-path=d/Cargo.toml
funca

Good! Now I want change d from binary crate to library crate. So, I want wasm lib calls wasm lib.
The first, I tried to compile my bin crate with --target=wasm32-wasi to get wasm and failed:

$cargo +nightly build --manifest-path=d/Cargo.toml --target=wasm32-wasi

   Compiling wat v1.0.13
   Compiling jobserver v0.1.21
   Compiling generic-array v0.12.3
   Compiling region v2.1.2
   Compiling gimli v0.20.0
error[E0425]: cannot find function `lock` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lock.rs:30:7
   |
30 |   os::lock(
   |       ^^^^ not found in `os`
   |
help: possible candidate is found in another module, you can import it into scope
   |
1  | use lock::lock;
   |

error[E0425]: cannot find function `unlock` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lock.rs:58:7
   |
58 |   os::unlock(
   |       ^^^^^^ not found in `os`
   |
help: possible candidate is found in another module, you can import it into scope
   |
1  | use lock::unlock;
   |

error[E0425]: cannot find function `page_size` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/page.rs:16:39
   |
16 |     INIT.call_once(|| PAGE_SIZE = os::page_size());
   |                                       ^^^^^^^^^ not found in `os`

error[E0425]: cannot find function `set_protection` in module `os`
  --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/protect.rs:40:7
   |
40 |   os::set_protection(
   |       ^^^^^^^^^^^^^^ not found in `os`

error[E0425]: cannot find function `get_region` in module `os`
   --> /opt/rust/cargo/registry/src/github.com-1ecc6299db9ec823/region-2.1.2/src/lib.rs:133:7
    |
133 |   os::get_region(page::floor(address as usize) as *const u8)
    |       ^^^^^^^^^^ not found in `os`

error: aborting due to 5 previous errors

For more information about this error, try `rustc --explain E0425`.
error: could not compile `region`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

So, I think doesn't region support --target=wasm32-wasi? How to create wasm calls wasm?

Wasmtime GitHub notifications bot (Mar 31 2020 at 15:29):

yurydelendik commented on Issue #1440:

Per zullip chat, more notes:

-wasmtime-cli does not have a way to configure a linking, (--preload is not a parameter that does that)

it is expected that wasmtime-cli will automatically resolve and load dependent modules.

currently, the embedding (e.g. https://github.com/bytecodealliance/wasmtime/blob/master/examples/linking.rs) is easiest way to do that

Wasmtime GitHub notifications bot (Mar 31 2020 at 15:29):

yurydelendik edited a comment on Issue #1440:

Per zullip chat, more notes:

wasmtime-cli does not have a way to configure a linking, (--preload is not a parameter that does that)

it is expected that wasmtime-cli will automatically resolve and load dependent modules.

currently, the embedding (e.g. https://github.com/bytecodealliance/wasmtime/blob/master/examples/linking.rs) is easiest way to do that

Wasmtime GitHub notifications bot (Mar 31 2020 at 15:30):

yurydelendik edited a comment on Issue #1440:

Per zullip chat, more notes:

wasmtime-cli does not have a way to configure linking, (--preload is not a parameter that does that)

it is expected that wasmtime-cli will automatically resolve and load dependent modules.

currently, the embedding (e.g. https://github.com/bytecodealliance/wasmtime/blob/master/examples/linking.rs) is easiest way to do that

Last updated: Dec 23 2024 at 12:05 UTC