Rely less on wasm-component-ld for tests (#1434)

* Rely less on `wasm-component-ld` for tests

This repository is often used to test experimental/upcoming features for
components such as async/etc, but this creates a chicken-and-egg problem
where it becomes difficult to compile tests. Many tests use upstream
toolchains which use `wasm-component-ld` (e.g. Rust/C tests) but it can
take time to get this updated. There's already logic to handle having
tests target wasip1 and running the wit-component step manually, so this
PR makes that step unconditional. This means that test binaries are
always assembled with a crate-dependency of `wit-component` which should
enable easier updates since it's "just" a Cargo dependency vs being part
of a toolchain in a separate project.

* Conditionally embed type information

Author: alexcrichton

.github/workflows/main.yml

@@ -122,7 +122,7 @@ jobs:
       with:
         submodules: true
     - name: Install Rust
-      run: rustup update nightly --no-self-update && rustup default nightly
+      run: rustup update stable --no-self-update && rustup default stable
     - run: rustup target add wasm32-wasip2
     - uses: ./.github/actions/install-wasi-sdk
     - run: |

crates/test/src/c.rs

@@ -123,11 +123,7 @@ fn compile(runner: &Runner<'_>, compile: &Compile<'_>, compiler: PathBuf) -> Res
 
     // Now compile the runner's source code to with the above object and the
     // component-type object into a final component.
-    let output = if produces_component(runner) {
-        compile.output.to_path_buf()
-    } else {
-        compile.output.with_extension("core.wasm")
-    };
+    let output = compile.output.with_extension("core.wasm");
     let mut cmd = Command::new(compiler);
     cmd.arg(&compile.component.path)
         .arg(&bindings_object)
@@ -154,13 +150,14 @@ fn compile(runner: &Runner<'_>, compile: &Compile<'_>, compiler: PathBuf) -> Res
             cmd.arg("-mexec-model=reactor");
         }
     }
+    if produces_component(runner) {
+        cmd.arg("-Wl,--skip-wit-component");
+    }
     runner.run_command(&mut cmd)?;
 
-    if !produces_component(runner) {
-        runner
-            .convert_p1_to_component(&output, compile)
-            .with_context(|| format!("failed to convert {output:?}"))?;
-    }
+    runner
+        .convert_p1_to_component(&output, compile)
+        .with_context(|| format!("failed to convert {output:?}"))?;
     Ok(())
 }
 

crates/test/src/lib.rs

@@ -999,14 +999,17 @@ status: {}",
             .context("failed to load WIT")?;
         let world = resolve.select_world(&[pkg], Some(&compile.component.bindgen.world))?;
         let mut module = fs::read(&p1).context("failed to read wasm file")?;
-        let encoded = wit_component::metadata::encode(&resolve, world, StringEncoding::UTF8, None)?;
 
-        let section = wasm_encoder::CustomSection {
-            name: Cow::Borrowed("component-type"),
-            data: Cow::Borrowed(&encoded),
-        };
-        module.push(section.id());
-        section.encode(&mut module);
+        if !has_component_type_sections(&module) {
+            let encoded =
+                wit_component::metadata::encode(&resolve, world, StringEncoding::UTF8, None)?;
+            let section = wasm_encoder::CustomSection {
+                name: Cow::Borrowed("component-type"),
+                data: Cow::Borrowed(&encoded),
+            };
+            module.push(section.id());
+            section.encode(&mut module);
+        }
 
         let wasi_adapter = match compile.component.kind {
             Kind::Runner => {
@@ -1071,6 +1074,18 @@ status: {}",
     }
 }
 
+fn has_component_type_sections(wasm: &[u8]) -> bool {
+    for payload in wasmparser::Parser::new(0).parse_all(wasm) {
+        match payload {
+            Ok(wasmparser::Payload::CustomSection(s)) if s.name().starts_with("component-type") => {
+                return true
+            }
+            _ => {}
+        }
+    }
+    false
+}
+
 struct StepResult<'a> {
     result: Result<()>,
     should_fail: bool,

crates/test/src/rust.rs

@@ -166,11 +166,7 @@ path = 'lib.rs'
         // If this rust target doesn't natively produce a component then place
         // the compiler output in a temporary location which is componentized
         // later on.
-        let output = if runner.produces_component() {
-            compile.output.to_path_buf()
-        } else {
-            compile.output.with_extension("core.wasm")
-        };
+        let output = compile.output.with_extension("core.wasm");
 
         // Compile all extern crates, if any
         let mut externs = Vec::new();
@@ -216,13 +212,14 @@ path = 'lib.rs'
                 cmd.arg("--crate-type=cdylib");
             }
         }
+        if runner.produces_component() {
+            cmd.arg("-Clink-arg=--skip-wit-component");
+        }
         runner.run_command(&mut cmd)?;
 
-        if !runner.produces_component() {
-            runner
-                .convert_p1_to_component(&output, compile)
-                .with_context(|| format!("failed to convert {output:?}"))?;
-        }
+        runner
+            .convert_p1_to_component(&output, compile)
+            .with_context(|| format!("failed to convert {output:?}"))?;
 
         Ok(())
     }