Expose type information in module translation (#5139)

This adds a new field `types` to `ModuleTranslation`, so that
consumers can have access to the module type information known after
validation has finished. This change is useful when consumers want to
have access to the type information in wasmparser's terms rather than
in wasmtime_environ's equivalent types (e.g. `WasmFuncType`).

crates/environ/src/module_environ.rs

@@ -14,7 +14,7 @@ use std::convert::{TryFrom, TryInto};
 use std::path::PathBuf;
 use std::sync::Arc;
 use wasmparser::{
-    CustomSectionReader, DataKind, ElementItem, ElementKind, Encoding, ExternalKind,
+    types::Types, CustomSectionReader, DataKind, ElementItem, ElementKind, Encoding, ExternalKind,
     FuncToValidate, FunctionBody, NameSectionReader, Naming, Operator, Parser, Payload, Type,
     TypeRef, Validator, ValidatorResources,
 };
@@ -90,6 +90,19 @@ pub struct ModuleTranslation<'data> {
     /// When we're parsing the code section this will be incremented so we know
     /// which function is currently being defined.
     code_index: u32,
+
+    /// The type information of the current module made available at the end of the
+    /// validation process.
+    types: Option<Types>,
+}
+
+impl<'data> ModuleTranslation<'data> {
+    /// Returns a reference to the type information of the current module.
+    pub fn get_types(&self) -> &Types {
+        self.types
+            .as_ref()
+            .expect("module type information to be available")
+    }
 }
 
 /// Contains function data: byte code and its offset in the module.
@@ -195,7 +208,7 @@ impl<'a, 'data> ModuleEnvironment<'a, 'data> {
             }
 
             Payload::End(offset) => {
-                self.validator.end(offset)?;
+                self.result.types = Some(self.validator.end(offset)?);
 
                 // With the `escaped_funcs` set of functions finished
                 // we can calculate the set of signatures that are exported as
@@ -622,7 +635,7 @@ impl<'a, 'data> ModuleEnvironment<'a, 'data> {
                     "\
 Support for interface types has temporarily been removed from `wasmtime`.
 
-For more information about this temoprary you can read on the issue online:
+For more information about this temporary change you can read on the issue online:
 
     https://github.com/bytecodealliance/wasmtime/issues/1271