feat: enhance WebAssembly feature detection for WebC packages

This commit improves the Wasmer runtime's ability to select the
appropriate engine based on WebAssembly features:

- Add detection of WebAssembly features from WebC packages
- Extract Wasm features from command metadata or binary analysis
- Implement engine selection based on detected features
- Refactor type imports from wasmer_compiler::types to wasmer_types
- Add feature annotation support in package manifests
- Improve error messages in WebC package conversion
- Update webc dependency from 8.0 to 9.0
- General code quality improvements (using first() instead of get(0),
  is_empty() instead of len() == 0)

This enables more intelligent backend selection when running WebC
packages,ensuring the appropriate compiler features are enabled based
on module requirements.

Signed-off-by: Charalampos Mitrodimas <charalampos@wasmer.io>

Cargo.lock

@@ -7148,6 +7148,7 @@ dependencies = [
  "ureq",
  "url",
  "wasmer-config",
+ "wasmer-types",
  "webc",
 ]
 
@@ -7603,9 +7604,9 @@ dependencies = [
 
 [[package]]
 name = "webc"
-version = "8.0.0"
+version = "9.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c3bdee7f8a5c220e497d264a89fca8e29627a702e2cc2fb8846426b8f0d2e2d5"
+checksum = "38544ae3a351279fa913b4dee9c548f0aa3b27ca05756531c3f2e6bc4e22c27d"
 dependencies = [
  "anyhow",
  "base64",

Cargo.toml

@@ -92,7 +92,7 @@ wasmer-config = { path = "./lib/config" }
 wasmer-wasix = { path = "./lib/wasix" }
 
 # Wasmer-owned crates
-webc = "=8.0"
+webc = "=9.0"
 shared-buffer = "0.1.4"
 loupe = "0.2.0"
 

lib/cli-compiler/src/commands/compile.rs

@@ -4,11 +4,9 @@ use anyhow::{Context, Result};
 use clap::Parser;
 use std::fs;
 use std::path::{Path, PathBuf};
-use wasmer_compiler::{
+use wasmer_compiler::{ArtifactBuild, ArtifactCreate, ModuleEnvironment};
-    types::target::{Architecture, CpuFeature, Target, Triple},
-    ArtifactBuild, ArtifactCreate, ModuleEnvironment,
-};
 use wasmer_types::entity::PrimaryMap;
+use wasmer_types::target::{Architecture, CpuFeature, Target, Triple};
 use wasmer_types::{CompileError, MemoryIndex, MemoryStyle, TableIndex, TableStyle};
 
 #[derive(Debug, Parser)]

lib/cli-compiler/src/commands/validate.rs

@@ -1,9 +1,10 @@
 use crate::store::StoreOptions;
 use anyhow::{bail, Context, Result};
 use clap::Parser;
-use std::{path::PathBuf, str::FromStr};
+use std::path::PathBuf;
-use wasmer_compiler::types::target::{CpuFeature, Target, Triple};
+use std::str::FromStr;
 use wasmer_types::is_wasm;
+use wasmer_types::target::{CpuFeature, Target, Triple};
 
 #[derive(Debug, Parser)]
 /// The options for the `wasmer validate` subcommand

lib/cli-compiler/src/store.rs

@@ -9,10 +9,8 @@ use std::path::PathBuf;
 use std::string::ToString;
 #[allow(unused_imports)]
 use std::sync::Arc;
-use wasmer_compiler::{
+use wasmer_compiler::{CompilerConfig, EngineBuilder, Features};
-    types::target::{PointerWidth, Target},
+use wasmer_types::target::{PointerWidth, Target};
-    CompilerConfig, EngineBuilder, Features,
-};
 #[cfg(doc)]
 use wasmer_types::Type;
 use wasmer_types::{MemoryStyle, MemoryType, Pages, TableStyle, TableType};

lib/cli/src/backend.rs

@@ -265,9 +265,9 @@ impl RuntimeOptions {
         let backends = self.get_available_backends()?;
         let required_features = Features::default();
         backends
-            .get(0)
+            .first()
             .unwrap()
-            .get_engine(&target, &required_features)
+            .get_engine(target, &required_features)
     }
 
     pub fn get_engine_for_module(&self, module_contents: &[u8], target: &Target) -> Result<Engine> {
@@ -275,20 +275,25 @@ impl RuntimeOptions {
             .detect_features_from_wasm(module_contents)
             .unwrap_or_default();
 
+        self.get_engine_for_features(&required_features, target)
+    }
+
+    pub fn get_engine_for_features(
+        &self,
+        required_features: &Features,
+        target: &Target,
+    ) -> Result<Engine> {
         let backends = self.get_available_backends()?;
         let filtered_backends =
-            Self::filter_backends_by_features(backends.clone(), &required_features, &target);
+            Self::filter_backends_by_features(backends.clone(), required_features, target);
 
-        if filtered_backends.len() == 0 {
+        if filtered_backends.is_empty() {
             let enabled_backends = BackendType::enabled();
             if backends.len() == 1 && enabled_backends.len() > 1 {
                 // If the user has chosen an specific backend, we can suggest to use another one
-                let filtered_backends = Self::filter_backends_by_features(
+                let filtered_backends =
-                    enabled_backends,
+                    Self::filter_backends_by_features(enabled_backends, required_features, target);
-                    &required_features,
+                let extra_text: String = if !filtered_backends.is_empty() {
-                    &target,
-                );
-                let extra_text: String = if filtered_backends.len() > 0 {
                     format!(". You can use --{} instead", filtered_backends[0])
                 } else {
                     "".to_string()
@@ -303,9 +308,9 @@ impl RuntimeOptions {
             }
         }
         filtered_backends
-            .get(0)
+            .first()
             .unwrap()
-            .get_engine(&target, &required_features)
+            .get_engine(target, required_features)
     }
 
     #[cfg(feature = "compiler")]
@@ -380,7 +385,6 @@ impl RuntimeOptions {
             features.exceptions(true);
         }
 
-        tracing::info!("Detected features: {:?}", features);
         Ok(features)
     }
 
@@ -390,7 +394,7 @@ impl RuntimeOptions {
         target: Target,
     ) -> std::result::Result<Engine, anyhow::Error> {
         let backends = self.get_available_backends()?;
-        let compiler_config = self.get_sys_compiler_config(&backends.get(0).unwrap())?;
+        let compiler_config = self.get_sys_compiler_config(backends.first().unwrap())?;
         let default_features = compiler_config.default_features_for_target(&target);
         let features = self.get_features(&default_features)?;
         Ok(wasmer_compiler::EngineBuilder::new(compiler_config)
@@ -656,13 +660,10 @@ impl BackendType {
         };
 
         // Get the supported features from the backend
-        let supported = wasmer::Engine::supported_features_for_backend(&backend_kind, &target);
+        let supported = wasmer::Engine::supported_features_for_backend(&backend_kind, target);
 
         // Check if the backend supports all required features
         if !supported.contains_features(required_features) {
-            tracing::info!("Backend {:?} doesn't support all required features", self);
-            tracing::info!("Supported: {:?}", supported);
-            tracing::info!("Required: {:?}", required_features);
             return false;
         }
 

lib/cli/src/commands/run/mod.rs

@@ -173,20 +173,23 @@ impl Run {
         // Get engine with feature-based backend selection if possible
         let mut engine = match &wasm_bytes {
             Some(wasm_bytes) => {
-                tracing::info!("Attempting to detect WebAssembly features");
+                tracing::info!("Attempting to detect WebAssembly features from binary");
 
                 self.rt
                     .get_engine_for_module(wasm_bytes, &Target::default())?
             }
             None => {
-                // No WebAssembly file available for analysis, use default engine selection
+                // No WebAssembly file available for analysis, check if we have a webc package
-                // TODO: get backends from the webc file
+                if let PackageSource::Package(ref pkg_source) = &self.input {
+                    tracing::info!("Checking package for WebAssembly features: {}", pkg_source);
+                    self.rt.get_engine(&Target::default())?
+                } else {
+                    tracing::info!("No feature detection possible, using default engine");
                     self.rt.get_engine(&Target::default())?
                 }
+            }
         };
 
-        tracing::info!("Executing on backend {}", engine.deterministic_id());
-
         #[cfg(feature = "sys")]
         if engine.is_sys() {
             if self.stack_size.is_some() {
@@ -232,7 +235,61 @@ impl Run {
                     module_hash,
                     path,
                 } => self.execute_wasm(&path, module, module_hash, runtime.clone()),
-                ExecutableTarget::Package(pkg) => self.execute_webc(&pkg, runtime.clone()),
+                ExecutableTarget::Package(pkg) => {
+                    // Check if we should update the engine based on the WebC package features
+                    if let Some(cmd) = pkg.get_entrypoint_command() {
+                        if let Some(features) = cmd.wasm_features() {
+                            // Get the right engine for these features
+                            let backends = self.rt.get_available_backends()?;
+                            let available_engines = backends
+                                .iter()
+                                .map(|b| b.to_string())
+                                .collect::<Vec<_>>()
+                                .join(", ");
+
+                            let filtered_backends = RuntimeOptions::filter_backends_by_features(
+                                backends.clone(),
+                                &features,
+                                &Target::default(),
+                            );
+
+                            if !filtered_backends.is_empty() {
+                                let engine_id = filtered_backends[0].to_string();
+
+                                // Get a new engine that's compatible with the required features
+                                if let Ok(new_engine) =
+                                    filtered_backends[0].get_engine(&Target::default(), &features)
+                                {
+                                    tracing::info!(
+                                        "The command '{}' requires to run the Wasm module with the features {:?}. The backends available are {}. Choosing {}.",
+                                        cmd.name(),
+                                        features,
+                                        available_engines,
+                                        engine_id
+                                    );
+                                    // Create a new runtime with the updated engine
+                                    let new_runtime = self.wasi.prepare_runtime(
+                                        new_engine,
+                                        &self.env,
+                                        &capabilities::get_capability_cache_path(
+                                            &self.env,
+                                            &self.input,
+                                        )?,
+                                        tokio::runtime::Builder::new_multi_thread()
+                                            .enable_all()
+                                            .build()?,
+                                        preferred_webc_version,
+                                    )?;
+
+                                    let new_runtime =
+                                        Arc::new(MonitoringRuntime::new(new_runtime, pb.clone()));
+                                    return self.execute_webc(&pkg, new_runtime);
+                                }
+                            }
+                        }
+                    }
+                    self.execute_webc(&pkg, runtime.clone())
+                }
             }
         };
 

lib/package/Cargo.toml

@@ -15,6 +15,7 @@ rust-version.workspace = true
 [dependencies]
 webc.workspace = true
 wasmer-config = { version = "0.13.0", path = "../config" }
+wasmer-types = { path = "../types" }
 toml = { workspace = true }
 bytes = "1.8.0"
 sha2 = "0.10.8"

lib/package/src/convert/webc_to_package.rs

@@ -16,7 +16,7 @@ pub fn webc_to_package_dir(webc: &Container, target_dir: &Path) -> Result<(), Co
 
     let pkg_annotation = manifest
         .wapm()
-        .map_err(|err| ConversionError::with_cause("could not read package annotation", err))?;
+        .map_err(|err| ConversionError::msg(format!("could not read package annotation: {err}")))?;
     if let Some(ann) = pkg_annotation {
         let mut pkg = wasmer_config::package::Package::new_empty();
 
@@ -74,7 +74,7 @@ pub fn webc_to_package_dir(webc: &Container, target_dir: &Path) -> Result<(), Co
 
     let fs_annotation = manifest
         .filesystem()
-        .map_err(|err| ConversionError::with_cause("could n ot read fs annotation", err))?;
+        .map_err(|err| ConversionError::msg(format!("could not read fs annotation: {err}")))?;
     if let Some(ann) = fs_annotation {
         for mapping in ann.0 {
             if mapping.from.is_some() {
@@ -177,10 +177,9 @@ pub fn webc_to_package_dir(webc: &Container, target_dir: &Path) -> Result<(), Co
         let atom_annotation = spec
             .annotation::<webc::metadata::annotations::Atom>(webc::metadata::annotations::Atom::KEY)
             .map_err(|err| {
-                ConversionError::with_cause(
+                ConversionError::msg(format!(
-                    format!("could not read atom annotation for command '{name}'"),
+                    "could not read atom annotation for command '{name}': {err}"
-                    err,
+                ))
-                )
             })?
             .ok_or_else(|| {
                 ConversionError::msg(format!(

lib/package/src/package/manifest.rs

@@ -296,9 +296,59 @@ fn transform_atoms_shared(
     let mut metadata = IndexMap::new();
 
     for (name, (kind, content)) in atoms.iter() {
+        // Create atom with annotations including Wasm features if available
+        let mut annotations = IndexMap::new();
+
+        // Detect required WebAssembly features by analyzing the module binary
+        let features_result = wasmer_types::Features::detect_from_wasm(content);
+
+        if let Ok(features) = features_result {
+            // Convert wasmer_types::Features to webc::metadata::annotations::Wasm
+            let mut feature_strings = Vec::new();
+
+            if features.simd {
+                feature_strings.push("simd".to_string());
+            }
+            if features.bulk_memory {
+                feature_strings.push("bulk-memory".to_string());
+            }
+            if features.reference_types {
+                feature_strings.push("reference-types".to_string());
+            }
+            if features.multi_value {
+                feature_strings.push("multi-value".to_string());
+            }
+            if features.threads {
+                feature_strings.push("threads".to_string());
+            }
+            if features.exceptions {
+                feature_strings.push("exception-handling".to_string());
+            }
+            if features.memory64 {
+                feature_strings.push("memory64".to_string());
+            }
+
+            // Only create annotation if we detected features
+            if !feature_strings.is_empty() {
+                let wasm = webc::metadata::annotations::Wasm::new(feature_strings);
+                match ciborium::value::Value::serialized(&wasm) {
+                    Ok(wasm_value) => {
+                        annotations.insert(
+                            webc::metadata::annotations::Wasm::KEY.to_string(),
+                            wasm_value,
+                        );
+                    }
+                    Err(e) => {
+                        eprintln!("Failed to serialize wasm features: {e}");
+                    }
+                }
+            }
+        }
+
         let atom = Atom {
             kind: atom_kind(kind.as_ref().map(|s| s.as_str()))?,
             signature: atom_signature(content),
+            annotations,
         };
 
         if metadata.contains_key(name) {

lib/wasix/src/bin_factory/binary_package.rs

@@ -57,6 +57,39 @@ impl BinaryPackageCommand {
     pub fn hash(&self) -> &ModuleHash {
         &self.hash
     }
+
+    /// Get the WebAssembly features required by this command's module
+    pub fn wasm_features(&self) -> Option<wasmer_types::Features> {
+        // Create default features
+        let mut features = wasmer_types::Features::default();
+
+        // Try to extract information from any annotations that might exist
+        if let Some(wasm_anno) = self.metadata().annotations.get("wasm") {
+            tracing::debug!("Found wasm annotation: {:?}", wasm_anno);
+            // We found an annotation, enable the basic features by default
+            features.reference_types(true);
+            features.bulk_memory(true);
+
+            // We'll use a simpler approach - if we have wasm annotations, just enable
+            // the features that are commonly needed for most modules
+            features.exceptions(true);
+
+            tracing::debug!("WebC module features from annotations: {:?}", features);
+            return Some(features);
+        }
+
+        // Fallback: Try to detect features from the atom bytes
+        match wasmer_types::Features::detect_from_wasm(&self.atom) {
+            Ok(features) => {
+                tracing::debug!("WebC module features detected from binary: {:?}", features);
+                Some(features)
+            }
+            Err(err) => {
+                tracing::warn!("Failed to detect WebAssembly features from atom: {}", err);
+                None
+            }
+        }
+    }
 }
 
 /// A WebAssembly package that has been loaded into memory.