wasmparser: optimize type section valiadation by specializing over Wasm feature subset (#1906)

* add specialized type section validation for Wasm feature subset

* use WasmFeatures getters

* apply rustfmt

* check first, then push types

* Revert "check first, then push types"

This reverts commit 213a72c.

* no longer apply fast validation when stack-switching is enabled

* apply rustfmt

* update comment

* allow-list features for fast type validation

* alphabetically order WasmFeatures in allow-list

* update comments about fast validation

* apply rustfmt

* fix fast validation compilation without features crate feature

Author: Robbepop

crates/wasmparser/src/validator/core.rs

@@ -569,9 +569,69 @@ impl Module {
                 offset,
             )?;
         }
+        if self.try_fast_validation(&rec_group, features, types, offset)? {
+            return Ok(());
+        }
         self.canonicalize_and_intern_rec_group(features, types, rec_group, offset)
     }
 
+    #[cfg(not(feature = "features"))]
+    fn try_fast_validation(
+        &mut self,
+        _rec_group: &RecGroup,
+        _features: &WasmFeatures,
+        _types: &mut TypeAlloc,
+        _offset: usize,
+    ) -> Result<bool> {
+        Ok(false)
+    }
+
+    /// Performs fast type section validation if possible.
+    ///
+    /// - Returns `Ok(true)` if fast validation was performed, else returns `Ok(false)`.
+    /// - Returns `Err(_)` if a type section validation error was encountered.
+    ///
+    /// # Note
+    ///
+    /// Fast type section validation can only be performed on a
+    /// statically known subset of `WasmFeatures`.
+    #[cfg(feature = "features")]
+    fn try_fast_validation(
+        &mut self,
+        rec_group: &RecGroup,
+        features: &WasmFeatures,
+        types: &mut TypeAlloc,
+        offset: usize,
+    ) -> Result<bool> {
+        /// The subset of `WasmFeatures` for which we know that the
+        /// fast type section validation can be safely applied.
+        ///
+        /// Fast type section validation does not have to canonicalize
+        /// (deduplicate) types and does not have to perform sub-typing
+        /// checks.
+        const FAST_VALIDATION_FEATURES: WasmFeatures = WasmFeatures::WASM2
+            .union(WasmFeatures::CUSTOM_PAGE_SIZES)
+            .union(WasmFeatures::EXTENDED_CONST)
+            .union(WasmFeatures::MEMORY64)
+            .union(WasmFeatures::MULTI_MEMORY)
+            .union(WasmFeatures::RELAXED_SIMD)
+            .union(WasmFeatures::TAIL_CALL)
+            .union(WasmFeatures::THREADS)
+            .union(WasmFeatures::WIDE_ARITHMETIC);
+        if !FAST_VALIDATION_FEATURES.contains(*features) {
+            return Ok(false);
+        }
+        if rec_group.is_explicit_rec_group() {
+            bail!(offset, "requires `gc` proposal to be enabled")
+        }
+        for ty in rec_group.types() {
+            let id = types.push(ty.clone());
+            self.add_type_id(id);
+            self.check_composite_type(&ty.composite_type, features, &types, offset)?;
+        }
+        Ok(true)
+    }
+
     pub fn add_import(
         &mut self,
         mut import: crate::Import,