[gc] Add final to heap type declarations

src/engine/BinParser.v3

@@ -861,53 +861,59 @@ class WasmParser(extensions: Extension.set, limits: Limits, module: Module,
 		return readByte("deftype code", BpConstants.renderDefTypeCode); // XXX: LEB not allowed here
 	}
 	def readDefSingleType(pt: int, code: byte, supertypes: Array<HeapType>) {
-		if (extensions.GC && code == BpDefTypeCode.SUB.code) {
-			var count = readU32_i("supertype count", limits.max_supertypes);
-			supertypes = Array<HeapType>.new(count);
-			for (i < count) {
-				var pt = decoder.pos;
-				var index = readU32_i("type index", u32.view(module.heaptypes.length));
-				supertypes[i] = toHeapType(pt, index);
-			}
-			pt = decoder.pos;
-			code = readDefTypeCode();
+		var final = 1;
+		if (extensions.GC) {
+			if (code == BpDefTypeCode.SUB.code) final = 0;
+			else if (code == BpDefTypeCode.SUB_FINAL.code) final = 1;
+			else final = 2;
+			if (final != 2) {
+				var count = readU32_i("supertype count", limits.max_supertypes);
+				supertypes = Array<HeapType>.new(count);
+				for (i < count) {
+					var pt = decoder.pos;
+					var index = readU32_i("type index", u32.view(module.heaptypes.length));
+					supertypes[i] = toHeapType(pt, index);
+				}
+				pt = decoder.pos;
+				code = readDefTypeCode();
 
-			if (subtype_list == null) subtype_list = Vector.new();
-			subtype_list.put(pt, module.heaptypes.length);
+				if (subtype_list == null) subtype_list = Vector.new();
+				subtype_list.put(pt, module.heaptypes.length);
+			}
 		}
 
 		match (code) {
-			BpDefTypeCode.Function.code => return readDefFuncType(supertypes);
-			BpDefTypeCode.Struct.code => if (extensions.GC) return readDefStructType(supertypes);
-			BpDefTypeCode.Array.code => if (extensions.GC) return readDefArrayType(supertypes);
+			BpDefTypeCode.Function.code => return readDefFuncType(final != 0, supertypes);
+			BpDefTypeCode.Struct.code => if (extensions.GC) return readDefStructType(final != 0, supertypes);
+			BpDefTypeCode.Array.code => if (extensions.GC) return readDefArrayType(final != 0, supertypes);
 		}
 		err.rel(decoder, pt).InvalidTypeDeclCode(code);
 	}
-	def readDefFuncType(supertypes: Array<HeapType>) {
+	def readDefFuncType(final: bool, supertypes: Array<HeapType>) {
 		var ptypes = readValueTypes("param count", limits.max_num_func_params);
 		if (!err.ok()) return;
 		var rtypes = readValueTypes("result count", limits.max_num_func_results);
 		if (!err.ok()) return;
-		var decl = SigDecl.new(supertypes, ptypes, rtypes);
+		var decl = SigDecl.new(final, supertypes, ptypes, rtypes);
 		module.addDecl(decl);
 		decl.recgrp_index = decl.heaptype_index - max_fw_index;
 	}
-	def readDefStructType(supertypes: Array<HeapType>) {
+	def readDefStructType(final: bool, supertypes: Array<HeapType>) {
 		var count = readU32_i("field count", limits.max_num_struct_fields);
 		if (!err.ok()) return;
 		var field_types = Array<StorageType>.new(count);
 		for (j < field_types.length) {
 			field_types[j] = readStorageType();
 		}
 		if (!err.ok()) return;
-		var decl = StructDecl.new(supertypes, field_types);
+		var decl = StructDecl.new(final, supertypes, field_types);
 		module.addDecl(decl);
 		decl.recgrp_index = decl.heaptype_index - max_fw_index;
 	}
-	def readDefArrayType(supertypes: Array<HeapType>) {
+	def readDefArrayType(final: bool, supertypes: Array<HeapType>) {
 		var elem_type = readStorageType();
 		if (!err.ok()) return;
-		var decl = ArrayDecl.new(supertypes, [elem_type]);
+		var decl = ArrayDecl.new(final, supertypes, [elem_type]);
 		module.addDecl(decl);
 		decl.recgrp_index = decl.heaptype_index - max_fw_index;
 	}

src/engine/Canon.v3

@@ -15,7 +15,7 @@ component Canon {
 		return SigDecl.!(globalCache.doOne(s));
 	}
 	def sigPR(params: Array<ValueType>, results: Array<ValueType>) -> SigDecl {
-		return sig(SigDecl.new(ValueTypes.NO_HEAPTYPES, params, results));
+		return sig(SigDecl.new(true, ValueTypes.NO_HEAPTYPES, params, results));
 	}
 }
 
@@ -133,16 +133,16 @@ class RecGroup(length: int) {
 		decls[cursor++] = d;
 		hash = hash * 33 + hashHeapTypeDecl(d);
 	}
-	def addStruct(supertypes: Array<HeapType>, fields: Array<StorageType>) -> this {
-		var d = decls[cursor++] = StructDecl.new(supertypes, fields);
+	def addStruct(final: bool, supertypes: Array<HeapType>, fields: Array<StorageType>) -> this {
+		var d = decls[cursor++] = StructDecl.new(final, supertypes, fields);
 		hash = hash * 33 + hashStructDecl(d);
 	}
-	def addArray(supertypes: Array<HeapType>, elems: Array<StorageType>) -> this {
-		var d = decls[cursor++] = ArrayDecl.new(supertypes, elems);
+	def addArray(final: bool, supertypes: Array<HeapType>, elems: Array<StorageType>) -> this {
+		var d = decls[cursor++] = ArrayDecl.new(final, supertypes, elems);
 		hash = hash * 33 + hashArrayDecl(d);
 	}
-	def addSig(supertypes: Array<HeapType>, params: Array<ValueType>, results: Array<ValueType>) -> this {
-		var d = decls[cursor++] = SigDecl.new(supertypes, params, results);
+	def addSig(final: bool, supertypes: Array<HeapType>, params: Array<ValueType>, results: Array<ValueType>) -> this {
+		var d = decls[cursor++] = SigDecl.new(final, supertypes, params, results);
 		hash = hash * 33 + hashSigDecl(d);
 	}
 
@@ -182,17 +182,17 @@ class RecGroup(length: int) {
 			match (d) {
 				x: StructDecl => {
 					if (isOpen || hasOpenStorageType(x.field_types)) {
-						d = StructDecl.new(ns, Arrays.dup(x.field_types));
+						d = StructDecl.new(x.final, ns, Arrays.dup(x.field_types));
 					}
 				}
 				x: ArrayDecl => {
 					if (isOpen || hasOpenStorageType(x.elem_types)) {
-						d = ArrayDecl.new(ns, Arrays.dup(x.elem_types));
+						d = ArrayDecl.new(x.final, ns, Arrays.dup(x.elem_types));
 					}
 				}
 				x: SigDecl => {
 					if (isOpen || hasOpenValueType(x.params) || hasOpenValueType(x.results)) {
-						d = SigDecl.new(ns, Arrays.dup(x.params), Arrays.dup(x.results));
+						d = SigDecl.new(x.final, ns, Arrays.dup(x.params), Arrays.dup(x.results));
 					}
 				}
 			}

src/engine/Opcodes.v3

@@ -795,7 +795,7 @@ class InstrTracer {
 					} else if (pl == 0 && rl == 1) {
 						pr.1[0].render(out);
 					} else {
-						SigDecl.new(null, pr.0, pr.1).render(out);
+						SigDecl.new(true, null, pr.0, pr.1).render(out);
 					}
 				}
 				LABEL => out.put1("depth=%d", parser.readLabel());

src/engine/SigCache.v3

@@ -135,7 +135,7 @@ component SigCache {
 	def is_v = S(arr_is, arr_v);
 
 	private def S(params: Array<ValueType>, results: Array<ValueType>) -> SigDecl {
-		var sig = SigDecl.new(ValueTypes.NO_HEAPTYPES, params, results);
+		var sig = SigDecl.new(true, ValueTypes.NO_HEAPTYPES, params, results);
 		Canon.globalCache.insert(sig);
 		return sig;
 	}

src/engine/Type.v3

@@ -81,6 +81,9 @@ component ValueTypes {
 	def NONE = Array<ValueType>.new(0);
 	def NO_HEAPTYPES = Array<HeapType>.new(0);
 
+	// Helper utility for a final signature type with no supertypes.
+	def newSig = SigDecl.new(true, NO_HEAPTYPES, _, _);
+
 	// Render a value type, careful not to recurse into any type in {seen}.
 	def render(vt: ValueType, seen: List<Decl>, buf: StringBuilder) -> StringBuilder {
 		var s: string;
@@ -389,7 +392,7 @@ component TypeRelation {
 }
 
 // Heap type declarations.
-class HeapTypeDecl(supertypes: Array<HeapType>) extends Decl {
+class HeapTypeDecl(final: bool, supertypes: Array<HeapType>) extends Decl {
 	var hash = 0;
 	var heaptype_index = -1;
 	var canon_id = -1;
@@ -420,7 +423,7 @@ class StructDecl extends HeapTypeDecl {
 	def field_types: Array<StorageType>;
 	def defaultable = allHaveDefaultValues(field_types);
 
-	new(supertypes: Array<HeapType>, field_types) super(supertypes) {}
+	new(final: bool, supertypes: Array<HeapType>, field_types) super(final, supertypes) {}
 
 	def render(buf: StringBuilder) -> StringBuilder {
 		return putUid(buf.put1("struct #%d", heaptype_index));
@@ -432,7 +435,7 @@ class ArrayDecl extends HeapTypeDecl {
 	def elem_types: Array<StorageType>;
 	def defaultable = allHaveDefaultValues(elem_types);
 
-	new(supertypes: Array<HeapType>, elem_types) super(supertypes) {}
+	new(final: bool, supertypes: Array<HeapType>, elem_types) super(final, supertypes) {}
 
 	def render(buf: StringBuilder) -> StringBuilder {
 		return putUid(buf.put1("array #%d", heaptype_index));
@@ -444,12 +447,12 @@ class SigDecl extends HeapTypeDecl {
 	def params: Array<ValueType>;
 	def results: Array<ValueType>;
 
-	new(supertypes: Array<HeapType>, params, results) super(supertypes) {}
+	new(final: bool, supertypes: Array<HeapType>, params, results) super(final, supertypes) {}
 
 	def bindLeft(count: int) -> SigDecl {
 		var p = params, np = Array<ValueType>.new(p.length - count);
 		for (i < np.length) np[i] = p[i + count];
-		return SigDecl.new(ValueTypes.NO_HEAPTYPES, np, results); // TODO: bindLeft of SigDecl.supertypes
+		return SigDecl.new(final, ValueTypes.NO_HEAPTYPES, np, results); // TODO: bindLeft of SigDecl.supertypes
 	}
 	def isAssignableSig(that: SigDecl) -> bool {
 		if (that == null) return false;
@@ -478,7 +481,7 @@ class SigDecl extends HeapTypeDecl {
 		return putUid(buf);
 	}
 	def dup() -> SigDecl {
-		var ns = SigDecl.new(supertypes, params, results);
+		var ns = SigDecl.new(final, supertypes, params, results);
 		ns.canon_id = this.canon_id;
 		return ns;
 	}

src/jawa/JawaClass.v3

@@ -26,7 +26,7 @@ enum JawaFieldAttr(code: u16) {
 	ENUM		(0x2000)
 }
 
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+def newSig = ValueTypes.newSig;
 
 // Method representation: attributes, signatures, and method declarations.
 class JawaMethod(name: JawaString, attrs: JawaMethodAttr.set, sig: JawaMethodSig, var impl: Function) {

src/jawa/JawaGcRuntime.v3

@@ -3,7 +3,7 @@
 
 // Implementation of the Jawa runtime using the GC extension to Wasm.
 def OUT = Trace.OUT;
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+def newSig = ValueTypes.newSig;
 
 class JawaGcRuntime extends JawaRuntime {
 	def arrayReps = HashMap<JawaArrayType, JawaGcRuntimeArrayRep>.new(JawaRefType.hashI32, JawaArrayType.==);
@@ -40,7 +40,7 @@ class JawaGcRuntime extends JawaRuntime {
 		var pair = newStructs(at, 1, parent.vtable.length),
 			objStruct = pair.1, metaStruct = pair.0;
 
-		var array = ArrayDecl.new(ValueTypes.NO_HEAPTYPES, Array.new(1));
+		var array = ArrayDecl.new(true, ValueTypes.NO_HEAPTYPES, Array.new(1));
 		comodule.addDecl(array);
 		arrayReps[at] = gcrep = JawaGcRuntimeArrayRep.new(metaStruct, objStruct, array);
 
@@ -201,7 +201,7 @@ class JawaGcRuntime extends JawaRuntime {
 		return gcrep;
 	}
 	def newStruct(t: JawaRefType, field_types: Array<StorageType>) -> StructDecl {
-		var objStruct = StructDecl.new(ValueTypes.NO_HEAPTYPES, field_types); // TODO: supertypes
+		var objStruct = StructDecl.new(true, ValueTypes.NO_HEAPTYPES, field_types); // TODO: supertypes
 		comodule.addDecl(objStruct);
 		if (t != null) reftypes.set(objStruct.heaptype_index, t);
 		return objStruct;

src/jawa/JawaHostRuntime.v3

@@ -1,7 +1,7 @@
 // Copyright 2020 Ben L. Titzer. All rights reserved.
 // See LICENSE for details of Apache 2.0 license.
 
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+def newSig = ValueTypes.newSig;
 
 // Implementation of the Jawa runtime using only the host language, Virgil.
 class JawaHostRuntime extends JawaRuntime {

src/jawa/JawaSysFuncs.v3

@@ -3,15 +3,15 @@
 
 // All the system functions supported by Jawa in the "SYSTEM" bytecode.
 enum JawaSysFunc(sig: SigDecl, eval: Array<Value> -> HostResult) {
-	puts(SigDecl.new(ValueTypes.NO_HEAPTYPES, [ValueType.Host(JawaTypes.STRING)], SigCache.arr_v), eval_puts),
+	puts(SigDecl.new(true, ValueTypes.NO_HEAPTYPES, [ValueType.Host(JawaTypes.STRING)], SigCache.arr_v), eval_puts),
 	puti(SigCache.i_v, eval_puti),
 	millis(SigCache.v_i, eval_millis),
 	micros(SigCache.v_i, eval_micros),
 	random(SigCache.v_l, eval_random),
 	exp(SigCache.d_d, eval_exp),
 	log(SigCache.d_d, eval_log),
 	sqrt(SigCache.d_d, eval_sqrt),
-	idhash(SigDecl.new(ValueTypes.NO_HEAPTYPES, [ValueType.Host(JawaTypes.OBJECT)], SigCache.arr_i), eval_idhash)
+	idhash(SigDecl.new(true, ValueTypes.NO_HEAPTYPES, [ValueType.Host(JawaTypes.OBJECT)], SigCache.arr_i), eval_idhash)
 }
 
 // System functions that can be imported by code.

src/modules/wasi/WspOneModule.v3

@@ -12,7 +12,7 @@ private enum PreopenType(code: byte) {
 // Registered functions in the "wasi_snapshot_preview1" module.
 def funcMap = Strings.newMap<(SigDecl, (WspOneModule, Array<Value>) -> HostResult)>(), X = init();
 def init() {
-	def i_ = ValueType.I32, l_ = ValueType.I64, s = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+	def i_ = ValueType.I32, l_ = ValueType.I64, s = SigDecl.new(true, ValueTypes.NO_HEAPTYPES, _, _);
 	def S: SigCache;
 	for (t in [
 		("args_get",		S.ii_i, 				WspOneModule.args_get),

src/modules/wizeng/WizengModule.v3

@@ -49,7 +49,7 @@ class WizengModule extends HostModule("wizeng") {
 
 				var sig_index = 0; // TODO: get correct sig index?
 				var func = new_funcref(sig, sig_index, _);
-				var imported_sig = SigDecl.new([], SigCache.arr_ii, [rtype]);
+				var imported_sig = SigDecl.new(true, [], SigCache.arr_ii, [rtype]);
 				result[j] = HostFunctionN.new("new_funcref", imported_sig, func);
 			}
 		}

test/unittest/CanonTest.v3

@@ -13,9 +13,9 @@ def X = [
 	()
 ];
 
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
-def newStruct = StructDecl.new(ValueTypes.NO_HEAPTYPES, _);
-def newArray = ArrayDecl.new(ValueTypes.NO_HEAPTYPES, _);
+def newSig = SigDecl.new(true, ValueTypes.NO_HEAPTYPES, _, _);
+def newStruct = StructDecl.new(true, ValueTypes.NO_HEAPTYPES, _);
+def newArray = ArrayDecl.new(true, ValueTypes.NO_HEAPTYPES, _);
 
 class CanonTester(t: Tester) {
 	def assertSigId(sig: SigDecl) {

test/unittest/CodeValidatorTest.v3

@@ -100,7 +100,7 @@ def X = [
 	()
 ];
 
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+def newSig = ValueTypes.newSig;
 
 class CodeValidatorTester(t: Tester) extends ModuleBuilder {
 	def err = ErrorGen.new("CodeValidatorTest.v3");
@@ -1522,7 +1522,7 @@ def test_call_ref0(t: CodeValidatorTester) {
 		t.sig(sig);
 		t.TypeError(code1, 1);
 
-		t.sig(SigDecl.new(null, [ref_v_v], SigCache.arr_v));
+		t.sig(newSig([ref_v_v], SigCache.arr_v));
 		var code2: Array<byte> = [Opcode.LOCAL_GET.code, 0, Opcode.CALL_REF.code, heapIndexByte(sig)];
 		if (sig == sig_v_v) t.valid(code2);
 		else t.TypeError(code2, 3);
@@ -1676,7 +1676,7 @@ def test_struct_newdef(t: CodeValidatorTester) {
 
 def test_struct_get(t: CodeValidatorTester) {
 	t.setExtensions(Extension.GC);
-	var st = StructDecl.new(ValueTypes.NO_HEAPTYPES, [unpackedT(ValueType.I32, true), unpackedT(ValueType.F32, true)]);
+	var st = StructDecl.new(true, ValueTypes.NO_HEAPTYPES, [unpackedT(ValueType.I32, true), unpackedT(ValueType.F32, true)]);
 	t.module.addDecl(st);
 
 	t.sig0([ValueTypes.RefStruct(false, st)], SigCache.arr_i);

test/unittest/ExeTest.v3

@@ -1034,7 +1034,7 @@ component TestTiers {
 
 def NO_IMPORTS = Array<Exportable>.new(0);
 
-def newSig = SigDecl.new(ValueTypes.NO_HEAPTYPES, _, _);
+def newSig = ValueTypes.newSig;
 
 class ExeTester(t: Tester, tiering: ExecutionStrategy) extends ModuleBuilder {
 	var max_call_depth = 100u;
@@ -1301,7 +1301,7 @@ def test_block1(i: ExeTester) {
 
 def test_block2(i: ExeTester) {
 	i.extensions |= Extension.GC;
-	i.sig(SigDecl.new(ValueTypes.NO_HEAPTYPES, SigCache.arr_g, SigCache.arr_g));
+	i.sig(newSig(SigCache.arr_g, SigCache.arr_g));
 	i.code([Opcode.BLOCK.code, BpTypeCode.REF_NULL.code,  BpTypeCode.FUNCREF.code,
 		Opcode.LOCAL_GET.code, 0,
 		Opcode.END.code]);
@@ -2010,7 +2010,7 @@ def test_locals4(i: ExeTester) {
 def test_locals5(i: ExeTester) {
 	var sig_v_i = i.addSig(SigCache.v_i);
 	var ft = ValueType.Ref(true, HeapType.Func(sig_v_i));
-	i.sig(SigDecl.new(ValueTypes.NO_HEAPTYPES, SigCache.arr_g, SigCache.arr_g));
+	i.sig(newSig(SigCache.arr_g, SigCache.arr_g));
 	var l = i.addLocals(1, ft);
 	i.code([
 		Opcode.LOCAL_GET.code, byte.!(l)
@@ -2705,7 +2705,7 @@ def uvu(a: u32, b: Value, c: u32) -> Array<Value> {
 }
 
 def test_table_fill(i: ExeTester) {
-	i.sig(SigDecl.new(ValueTypes.NO_HEAPTYPES, [ValueType.I32, ValueTypes.FUNCREF, ValueType.I32], SigCache.arr_v));
+	i.sig(newSig([ValueType.I32, ValueTypes.FUNCREF, ValueType.I32], SigCache.arr_v));
 	i.addTable(6, 0, []);
 	i.code([
 		Opcode.LOCAL_GET.code, 0,
@@ -3304,7 +3304,7 @@ def test_abstype_default(t: ExeTester) {
 		var module = Module.new(null);
 		var abs = AbsTypeDecl.new(true, c.0 == ValueTypes.EXTERNREF, []);
 		var at = ValueType.Abstract(abs);
-		var sig = SigDecl.new(ValueTypes.NO_HEAPTYPES, SigCache.arr_v, [at]);
+		var sig = newSig(SigCache.arr_v, [at]);
 		module.addDecl(abs);
 		module.addImport("foo", "bar", [], abs);
 		module.addDecl(sig);