get rid of linker Rc cycle, and add debug info to test programs

crates/test-programs/build.rs

@@ -44,6 +44,7 @@ mod wasi_tests {
 
     fn build_tests(testsuite: &str, out_dir: &Path) -> io::Result<()> {
         let mut cmd = Command::new("cargo");
+        cmd.env("CARGO_PROFILE_RELEASE_DEBUG", "1");
         cmd.args(&[
             "build",
             "--release",

crates/test-programs/tests/wasm_tests/runtime.rs

@@ -6,7 +6,7 @@ use wasi_c2::{
     virt::pipe::{ReadPipe, WritePipe},
     WasiCtx,
 };
-use wasmtime::{Linker, Module, Store};
+use wasmtime::{Config, Engine, Linker, Module, Store};
 
 pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> anyhow::Result<()> {
     let stdout = WritePipe::new_in_memory();
@@ -40,13 +40,12 @@ pub fn instantiate(data: &[u8], bin_name: &str, workspace: Option<&Path>) -> any
         snapshot1.add_to_linker(&mut linker)?;
 
         let module = Module::new(store.engine(), &data).context("failed to create wasm module")?;
-
-        linker
-            .module("", &module)
-            .and_then(|m| m.get_default(""))
-            .and_then(|f| f.get0::<()>())
-            .and_then(|f| f().map_err(Into::into))
+        let instance = linker.instantiate(&module)?;
+        let start = instance.get_func("_start").unwrap();
+        let with_type = start.get0::<()>()?;
+        with_type().map_err(anyhow::Error::from)
     };
+
     match r {
         Ok(()) => Ok(()),
         Err(trap) => {