Implement exception objects.

crates/c-api/src/val.rs

@@ -96,6 +96,7 @@ impl wasm_val_t {
             },
             Val::AnyRef(_) => crate::abort("creating a wasm_val_t from an anyref"),
             Val::ExternRef(_) => crate::abort("creating a wasm_val_t from an externref"),
+            Val::ExnRef(_) => crate::abort("creating a wasm_val_t from  an exnref"),
             Val::V128(_) => crate::abort("creating a wasm_val_t from a v128"),
         }
     }
@@ -251,6 +252,7 @@ impl wasmtime_val_t {
                     funcref: func.into(),
                 },
             },
+            Val::ExnRef(_) => crate::abort("exnrefs not yet supported in C API"),
             Val::V128(val) => wasmtime_val_t {
                 kind: crate::WASMTIME_V128,
                 of: wasmtime_val_union {

crates/cranelift/src/func_environ.rs

@@ -1514,6 +1514,9 @@ impl<'a, 'func, 'module_env> Call<'a, 'func, 'module_env> {
             | WasmHeapType::ConcreteArray(_)
             | WasmHeapType::Struct
             | WasmHeapType::ConcreteStruct(_)
+            | WasmHeapType::Exn
+            | WasmHeapType::ConcreteExn(_)
+            | WasmHeapType::NoExn
             | WasmHeapType::None => {
                 unreachable!()
             }
@@ -1741,7 +1744,7 @@ impl<'module_environment> TargetEnvironment for FuncEnvironment<'module_environm
     fn reference_type(&self, wasm_ty: WasmHeapType) -> (ir::Type, bool) {
         let ty = crate::reference_type(wasm_ty, self.pointer_type());
         let needs_stack_map = match wasm_ty.top() {
-            WasmHeapTopType::Extern | WasmHeapTopType::Any => true,
+            WasmHeapTopType::Extern | WasmHeapTopType::Any | WasmHeapTopType::Exn => true,
             WasmHeapTopType::Func => false,
             WasmHeapTopType::Cont => todo!(), // FIXME: #10248 stack switching support.
         };
@@ -1838,7 +1841,7 @@ impl FuncEnvironment<'_> {
         let heap_ty = table.ref_type.heap_type;
         match heap_ty.top() {
             // GC-managed types.
-            WasmHeapTopType::Any | WasmHeapTopType::Extern => {
+            WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Exn => {
                 let (src, flags) = table_data.prepare_table_addr(self, builder, index);
                 gc::gc_compiler(self)?.translate_read_gc_reference(
                     self,
@@ -1872,7 +1875,7 @@ impl FuncEnvironment<'_> {
         let heap_ty = table.ref_type.heap_type;
         match heap_ty.top() {
             // GC-managed types.
-            WasmHeapTopType::Any | WasmHeapTopType::Extern => {
+            WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Exn => {
                 let (dst, flags) = table_data.prepare_table_addr(self, builder, index);
                 gc::gc_compiler(self)?.translate_write_gc_reference(
                     self,
@@ -2254,7 +2257,9 @@ impl FuncEnvironment<'_> {
         Ok(match ht.top() {
             WasmHeapTopType::Func => pos.ins().iconst(self.pointer_type(), 0),
             // NB: null GC references don't need to be in stack maps.
-            WasmHeapTopType::Any | WasmHeapTopType::Extern => pos.ins().iconst(types::I32, 0),
+            WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Exn => {
+                pos.ins().iconst(types::I32, 0)
+            }
             WasmHeapTopType::Cont => todo!(), // FIXME: #10248 stack switching support.
         })
     }

crates/cranelift/src/func_environ/gc/enabled.rs

@@ -117,8 +117,10 @@ fn read_field_at_addr(
             WasmValType::F64 => builder.ins().load(ir::types::F64, flags, addr, 0),
             WasmValType::V128 => builder.ins().load(ir::types::I8X16, flags, addr, 0),
             WasmValType::Ref(r) => match r.heap_type.top() {
-                WasmHeapTopType::Any | WasmHeapTopType::Extern => gc_compiler(func_env)?
-                    .translate_read_gc_reference(func_env, builder, r, addr, flags)?,
+                WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Exn => {
+                    gc_compiler(func_env)?
+                        .translate_read_gc_reference(func_env, builder, r, addr, flags)?
+                }
                 WasmHeapTopType::Func => {
                     let expected_ty = match r.heap_type {
                         WasmHeapType::Func => ModuleInternedTypeIndex::reserved_value(),
@@ -1042,6 +1044,8 @@ pub fn translate_ref_test(
         | WasmHeapType::NoFunc
         | WasmHeapType::Cont
         | WasmHeapType::NoCont
+        | WasmHeapType::Exn
+        | WasmHeapType::NoExn
         | WasmHeapType::I31 => unreachable!("handled top, bottom, and i31 types above"),
 
         // For these abstract but non-top and non-bottom types, we check the
@@ -1057,7 +1061,9 @@ pub fn translate_ref_test(
         // TODO: This check should ideally be done inline, but we don't have a
         // good way to access the `TypeRegistry`'s supertypes arrays from Wasm
         // code at the moment.
-        WasmHeapType::ConcreteArray(ty) | WasmHeapType::ConcreteStruct(ty) => {
+        WasmHeapType::ConcreteArray(ty)
+        | WasmHeapType::ConcreteStruct(ty)
+        | WasmHeapType::ConcreteExn(ty) => {
             let expected_interned_ty = ty.unwrap_module_type_index();
             let expected_shared_ty =
                 func_env.module_interned_to_shared_ty(&mut builder.cursor(), expected_interned_ty);
@@ -1417,6 +1423,8 @@ impl FuncEnvironment<'_> {
             // Can only ever be `null`.
             WasmHeapType::NoExtern => false,
 
+            WasmHeapType::Exn | WasmHeapType::ConcreteExn(_) | WasmHeapType::NoExn => false,
+
             // Wrong type hierarchy, and also funcrefs are not GC-managed
             // types. Should have been caught by the assertion at the start of
             // the function.

crates/cranelift/src/lib.rs

@@ -212,7 +212,7 @@ fn wasm_call_signature(
 fn reference_type(wasm_ht: WasmHeapType, pointer_type: ir::Type) -> ir::Type {
     match wasm_ht.top() {
         WasmHeapTopType::Func => pointer_type,
-        WasmHeapTopType::Any | WasmHeapTopType::Extern => ir::types::I32,
+        WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Exn => ir::types::I32,
         WasmHeapTopType::Cont =>
         // TODO(10248) This is added in a follow-up PR
         {

crates/environ/src/compile/module_environ.rs

@@ -1220,7 +1220,10 @@ impl ModuleTranslation<'_> {
                 // initializer won't trap so we could continue processing
                 // segments, but that's left as a future optimization if
                 // necessary.
-                WasmHeapTopType::Any | WasmHeapTopType::Extern | WasmHeapTopType::Cont => break,
+                WasmHeapTopType::Any
+                | WasmHeapTopType::Extern
+                | WasmHeapTopType::Cont
+                | WasmHeapTopType::Exn => break,
             }
 
             // Function indices can be optimized here, but fully general

crates/environ/src/compile/module_types.rs

@@ -441,6 +441,7 @@ where
                         WasmCompositeInnerType::Func(_) => WasmHeapType::ConcreteFunc(index),
                         WasmCompositeInnerType::Struct(_) => WasmHeapType::ConcreteStruct(index),
                         WasmCompositeInnerType::Cont(_) => WasmHeapType::ConcreteCont(index),
+                        WasmCompositeInnerType::Exn(_) => WasmHeapType::ConcreteExn(index),
                     }
                 } else if let Some((wasmparser_types, _)) = self.rec_group_context.as_ref() {
                     let wasmparser_ty = &wasmparser_types[id].composite_type;
@@ -481,6 +482,7 @@ where
                         WasmCompositeInnerType::Func(_) => WasmHeapType::ConcreteFunc(index),
                         WasmCompositeInnerType::Struct(_) => WasmHeapType::ConcreteStruct(index),
                         WasmCompositeInnerType::Cont(_) => WasmHeapType::ConcreteCont(index),
+                        WasmCompositeInnerType::Exn(_) => WasmHeapType::ConcreteExn(index),
                     }
                 } else if let Some((parser_types, rec_group)) = self.rec_group_context.as_ref() {
                     let rec_group_index = interned.index() - self.types.types.len_types();