[wasm] Remove anyref subtyping

All subtyping has been removed from the reference-types proposal. This
CL implements this proposal change now in V8.

R=manoskouk@chromium.org

Bug: v8:10556
Change-Id: I08ef064952278e03ea655461fa9f0c96426157c7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2222345
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68152}

src/wasm/value-type.h

@@ -121,9 +121,7 @@ class ValueType {
   // TODO(7748): Extend this with struct and function subtyping.
   //             Keep up to date with funcref vs. anyref subtyping.
   constexpr bool IsSubTypeOf(ValueType other) const {
-    return (*this == other) || (other.kind() == kAnyRef && IsReferenceType()) ||
-           (kind() == kNullRef && other.kind() != kRef &&
-            other.IsReferenceType()) ||
+    return (*this == other) ||
            (other.kind() == kEqRef &&
             (kind() == kExnRef || kind() == kOptRef || kind() == kRef)) ||
            (kind() == kRef && other.kind() == kOptRef &&

test/mjsunit/mjsunit.status

@@ -324,7 +324,6 @@
   'regress/regress-crbug-1047368': [SKIP],
   'regress/wasm/*': [SKIP],
   'regress/regress-8947': [SKIP],
-  'regress/regress-9165': [SKIP],
   'regress/regress-9209': [SKIP],
   'regress/regress-1034394': [SKIP],
   'regress/regress-v8-9106': [SKIP],

test/mjsunit/regress/regress-9165.js

-// Copyright 2018 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --experimental-wasm-anyref
-
-load("test/mjsunit/wasm/wasm-module-builder.js");
-
-let kSig_r_i = makeSig([kWasmI32], [kWasmAnyRef]);
-
-(function TestMergeOfAnyFuncIntoAnyRef() {
-  print(arguments.callee.name);
-  let builder = new WasmModuleBuilder();
-  builder.addFunction("merge", kSig_r_i)
-      .addLocals({anyref_count: 1, anyfunc_count: 1})
-      .addBody([
-        kExprLocalGet, 0,
-        kExprI32Eqz,
-        kExprIf, kWasmAnyRef,
-          kExprLocalGet, 1,
-        kExprElse,
-          kExprLocalGet, 2,
-        kExprEnd,
-      ]).exportFunc();
-  let instance = builder.instantiate();
-  assertEquals(null, instance.exports.merge(0));
-  assertEquals(null, instance.exports.merge(1));
-})();
-
-(function TestMergeOfAnyFuncIntoNullRef() {
-  print(arguments.callee.name);
-  let builder = new WasmModuleBuilder();
-  builder.addFunction("merge", kSig_r_i)
-      .addLocals({anyfunc_count: 1})
-      .addBody([
-        kExprLocalGet, 0,
-        kExprI32Eqz,
-        kExprIf, kWasmAnyRef,
-          kExprRefNull, kWasmAnyRef,
-        kExprElse,
-          kExprLocalGet, 1,
-        kExprEnd,
-      ]).exportFunc();
-  let instance = builder.instantiate();
-  assertEquals(null, instance.exports.merge(0));
-  assertEquals(null, instance.exports.merge(1));
-})();

test/mjsunit/wasm/anyfunc.js

@@ -183,32 +183,6 @@ load('test/mjsunit/wasm/wasm-module-builder.js');
   assertEquals(null, main());
 })();
 
-(function testImplicitReturnAnyFuncAsAnyRef() {
-  print(arguments.callee.name);
-  const builder = new WasmModuleBuilder();
-  const sig_index = builder.addType(kSig_r_v);
-  builder.addFunction('main', sig_index)
-      .addLocals({anyfunc_count: 1})
-      .addBody([kExprLocalGet, 0])
-      .exportFunc();
-
-  const main = builder.instantiate().exports.main;
-  assertEquals(null, main());
-})();
-
-(function testExplicitReturnAnyFuncAsAnyRef() {
-  print(arguments.callee.name);
-  const builder = new WasmModuleBuilder();
-  const sig_index = builder.addType(kSig_r_v);
-  builder.addFunction('main', sig_index)
-      .addLocals({anyfunc_count: 1})
-      .addBody([kExprLocalGet, 0, kExprReturn])
-      .exportFunc();
-
-  const main = builder.instantiate().exports.main;
-  assertEquals(null, main());
-})();
-
 (function testRefFuncOutOfBounds() {
   print(arguments.callee.name);
   const builder = new WasmModuleBuilder();

test/mjsunit/wasm/anyref-globals.js

@@ -529,20 +529,6 @@ function dummy_func() {
   assertEquals(obj3, instance2.exports.reexport3.value);
 })();
 
-(function TestImportImmutableAnyFuncGlobalAsAnyRef() {
-  print(arguments.callee.name);
-  let builder1 = new WasmModuleBuilder();
-  const g3 = builder1.addGlobal(kWasmAnyFunc, true).exportAs("e3");
-  builder1.addGlobal(kWasmAnyRef, false).exportAs("e1"); // Dummy.
-  builder1.addGlobal(kWasmAnyFunc, false).exportAs("e2"); // Dummy.
-  const instance1 = builder1.instantiate();
-
-  let builder2 = new WasmModuleBuilder();
-  const i1 = builder2.addImportedGlobal('exports', 'e1', kWasmAnyRef, false);
-  const i2 = builder2.addImportedGlobal('exports', 'e2', kWasmAnyRef, false);
-  builder2.instantiate(instance1);
-})();
-
 (function TestImportMutableAnyFuncGlobalAsAnyRefFails() {
   print(arguments.callee.name);
   let builder1 = new WasmModuleBuilder();

test/mjsunit/wasm/exceptions-anyref.js

@@ -104,7 +104,7 @@ load("test/mjsunit/wasm/exceptions-utils.js");
   print(arguments.callee.name);
   let builder = new WasmModuleBuilder();
   let except = builder.addException(kSig_v_a);
-  builder.addFunction("throw_catch_local", kSig_r_v)
+  builder.addFunction("throw_catch_local", kSig_a_v)
       .addLocals({anyfunc_count: 1})
       .addBody([
         kExprTry, kWasmAnyFunc,

test/mjsunit/wasm/multi-table-element-section.js

@@ -78,21 +78,3 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
   assertEquals(value4, table4.get(offset4 + 1)());
   assertEquals(value3, table4.get(offset4 + 2)());
 })();
-
-(function TestAnyRefTableWithAnyFuncInit() {
-  print(arguments.callee.name);
-  let builder = new WasmModuleBuilder();
-  const table = builder.addTable(kWasmAnyRef, 5).index;
-  builder.addExportOfKind("table", kExternalTable, table);
-  const f1 = builder.addFunction('f1', kSig_i_v)
-                    .addBody([kExprI32Const, 11])
-                    .exportFunc().index;
-  const f2 = builder.addFunction('f2', kSig_i_v)
-                    .addBody([kExprI32Const, 22])
-                    .exportFunc().index;
-
-  builder.addElementSegment(table, 1, false, [f1, f2]);
-  const instance = builder.instantiate();
-  assertEquals(instance.exports.table.get(1)(), 11);
-  assertEquals(instance.exports.table.get(2)(), 22);
-})();

test/unittests/wasm/function-body-decoder-unittest.cc

@@ -1942,14 +1942,11 @@ TEST_F(FunctionBodyDecoderTest, TableSet) {
   byte tab_func1 = builder.AddTable(kWasmFuncRef, 20, true, 30);
   byte tab_func2 = builder.AddTable(kWasmFuncRef, 10, false, 20);
   byte tab_ref2 = builder.AddTable(kWasmAnyRef, 10, false, 20);
-  byte tab_null1 = builder.AddTable(kWasmNullRef, 10, true, 20);
-  byte tab_null2 = builder.AddTable(kWasmNullRef, 10, false, 20);
-  ValueType sig_types[]{kWasmAnyRef, kWasmFuncRef, kWasmNullRef, kWasmI32};
-  FunctionSig sig(0, 4, sig_types);
+  ValueType sig_types[]{kWasmAnyRef, kWasmFuncRef, kWasmI32};
+  FunctionSig sig(0, 3, sig_types);
   byte local_ref = 0;
   byte local_func = 1;
-  byte local_null = 2;
-  byte local_int = 3;
+  byte local_int = 2;
   ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref1, WASM_I32V(6),
                                         WASM_GET_LOCAL(local_ref))});
   ExpectValidates(&sig, {WASM_TABLE_SET(tab_func1, WASM_I32V(5),
@@ -1959,55 +1956,26 @@ TEST_F(FunctionBodyDecoderTest, TableSet) {
   ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref2, WASM_I32V(8),
                                         WASM_GET_LOCAL(local_ref))});
 
-  // We can store funcref values as anyref, but not the other way around.
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref1, WASM_I32V(4),
-                                        WASM_GET_LOCAL(local_func))});
+  // Only values of the correct type can be set to a table.
+  ExpectFailure(&sig, {WASM_TABLE_SET(tab_ref1, WASM_I32V(4),
+                                      WASM_GET_LOCAL(local_func))});
   ExpectFailure(&sig, {WASM_TABLE_SET(tab_func1, WASM_I32V(9),
                                       WASM_GET_LOCAL(local_ref))});
   ExpectFailure(&sig, {WASM_TABLE_SET(tab_func2, WASM_I32V(3),
                                       WASM_GET_LOCAL(local_ref))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref2, WASM_I32V(2),
-                                        WASM_GET_LOCAL(local_func))});
+  ExpectFailure(&sig, {WASM_TABLE_SET(tab_ref2, WASM_I32V(2),
+                                      WASM_GET_LOCAL(local_func))});
   ExpectFailure(&sig, {WASM_TABLE_SET(tab_ref1, WASM_I32V(9),
                                       WASM_GET_LOCAL(local_int))});
   ExpectFailure(&sig, {WASM_TABLE_SET(tab_func1, WASM_I32V(3),
                                       WASM_GET_LOCAL(local_int))});
 
-  // We can store nullref values as funcref or anyref but not the other way
-  // round.
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_null1, WASM_I32V(3),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref1, WASM_I32V(8),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_func1, WASM_I32V(8),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null1, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_ref))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null1, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_func))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null1, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_int))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_null2, WASM_I32V(3),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_ref2, WASM_I32V(8),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectValidates(&sig, {WASM_TABLE_SET(tab_func2, WASM_I32V(8),
-                                        WASM_GET_LOCAL(local_null))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null2, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_ref))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null2, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_func))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(tab_null2, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_int))});
-
   // Out-of-bounds table index should fail.
   byte oob_tab = 37;
   ExpectFailure(
       &sig, {WASM_TABLE_SET(oob_tab, WASM_I32V(9), WASM_GET_LOCAL(local_ref))});
   ExpectFailure(&sig, {WASM_TABLE_SET(oob_tab, WASM_I32V(3),
                                       WASM_GET_LOCAL(local_func))});
-  ExpectFailure(&sig, {WASM_TABLE_SET(oob_tab, WASM_I32V(3),
-                                      WASM_GET_LOCAL(local_null))});
 }
 
 TEST_F(FunctionBodyDecoderTest, TableGet) {
@@ -2037,15 +2005,13 @@ TEST_F(FunctionBodyDecoderTest, TableGet) {
       &sig, {WASM_SET_LOCAL(local_ref, WASM_SEQ(WASM_I32V(6), kExprTableGet,
                                                 U32V_2(tab_ref1)))});
 
-  // We can store funcref values as anyref, but not the other way around.
+  // We cannot store references as any other type.
   ExpectFailure(&sig, {WASM_SET_LOCAL(local_func,
                                       WASM_TABLE_GET(tab_ref1, WASM_I32V(4)))});
-  ExpectValidates(
-      &sig,
-      {WASM_SET_LOCAL(local_ref, WASM_TABLE_GET(tab_func1, WASM_I32V(9)))});
-  ExpectValidates(
-      &sig,
-      {WASM_SET_LOCAL(local_ref, WASM_TABLE_GET(tab_func2, WASM_I32V(3)))});
+  ExpectFailure(&sig, {WASM_SET_LOCAL(
+                          local_ref, WASM_TABLE_GET(tab_func1, WASM_I32V(9)))});
+  ExpectFailure(&sig, {WASM_SET_LOCAL(
+                          local_ref, WASM_TABLE_GET(tab_func2, WASM_I32V(3)))});
   ExpectFailure(&sig, {WASM_SET_LOCAL(local_func,
                                       WASM_TABLE_GET(tab_ref2, WASM_I32V(2)))});
 
@@ -3208,7 +3174,6 @@ TEST_F(FunctionBodyDecoderTest, TableCopyWrongType) {
 TEST_F(FunctionBodyDecoderTest, TableGrow) {
   byte tab_func = builder.AddTable(kWasmFuncRef, 10, true, 20);
   byte tab_ref = builder.AddTable(kWasmAnyRef, 10, true, 20);
-  byte tab_null = builder.AddTable(kWasmNullRef, 10, true, 20);
 
   ExpectFailure(
       sigs.i_a(),
@@ -3220,22 +3185,12 @@ TEST_F(FunctionBodyDecoderTest, TableGrow) {
   ExpectValidates(
       sigs.i_r(),
       {WASM_TABLE_GROW(tab_ref, WASM_REF_NULL(kLocalAnyRef), WASM_ONE)});
-  // FuncRef table cannot be initialized with an anyref value.
+  // FuncRef table cannot be initialized with an AnyRef value.
   ExpectFailure(sigs.i_r(),
                 {WASM_TABLE_GROW(tab_func, WASM_GET_LOCAL(0), WASM_ONE)});
-  // FuncRef table can be initialized with a nullref value.
-  ExpectValidates(sigs.i_n(),
-                  {WASM_TABLE_GROW(tab_func, WASM_GET_LOCAL(0), WASM_ONE)});
-  // Anyref table can be initialized with an funcref or nullref value.
-  ExpectValidates(sigs.i_a(),
-                  {WASM_TABLE_GROW(tab_ref, WASM_GET_LOCAL(0), WASM_ONE)});
-  ExpectValidates(sigs.i_n(),
-                  {WASM_TABLE_GROW(tab_ref, WASM_GET_LOCAL(0), WASM_ONE)});
-  // NullRef table cannot be initialized with an funcref or anyref value.
+  // AnyRef table cannot be initialized with a FuncRef value.
   ExpectFailure(sigs.i_a(),
-                {WASM_TABLE_GROW(tab_null, WASM_GET_LOCAL(0), WASM_ONE)});
-  ExpectFailure(sigs.i_r(),
-                {WASM_TABLE_GROW(tab_null, WASM_GET_LOCAL(0), WASM_ONE)});
+                {WASM_TABLE_GROW(tab_ref, WASM_GET_LOCAL(0), WASM_ONE)});
   // Check that the table index gets verified.
   ExpectFailure(
       sigs.i_r(),
@@ -3265,17 +3220,12 @@ TEST_F(FunctionBodyDecoderTest, TableFill) {
   ExpectValidates(sigs.v_r(),
                   {WASM_TABLE_FILL(tab_ref, WASM_ONE,
                                    WASM_REF_NULL(kLocalAnyRef), WASM_ONE)});
-  // FuncRef table cannot be initialized with an anyref value.
+  // FuncRef table cannot be initialized with an AnyRef value.
   ExpectFailure(sigs.v_r(), {WASM_TABLE_FILL(tab_func, WASM_ONE,
                                              WASM_GET_LOCAL(0), WASM_ONE)});
-  // FuncRef table can be initialized with an nullref value.
-  ExpectValidates(sigs.v_n(), {WASM_TABLE_FILL(tab_func, WASM_ONE,
-                                               WASM_GET_LOCAL(0), WASM_ONE)});
-  // Anyref table can be initialized with an funcref or nullref value.
-  ExpectValidates(sigs.v_a(), {WASM_TABLE_FILL(tab_ref, WASM_ONE,
-                                               WASM_GET_LOCAL(0), WASM_ONE)});
-  ExpectValidates(sigs.v_n(), {WASM_TABLE_FILL(tab_ref, WASM_ONE,
-                                               WASM_GET_LOCAL(0), WASM_ONE)});
+  // AnyRef table cannot be initialized with a FuncRef value.
+  ExpectFailure(sigs.v_a(), {WASM_TABLE_FILL(tab_ref, WASM_ONE,
+                                             WASM_GET_LOCAL(0), WASM_ONE)});
   // Check that the table index gets verified.
   ExpectFailure(sigs.v_r(),
                 {WASM_TABLE_FILL(tab_ref + 2, WASM_ONE,
@@ -3358,7 +3308,7 @@ TEST_F(FunctionBodyDecoderTest, TableInitMultiTable) {
   {
     TestModuleBuilder builder;
     builder.AddTable(kWasmAnyRef, 10, true, 20);
-    builder.AddPassiveElementSegment(wasm::kWasmFuncRef);
+    builder.AddPassiveElementSegment(wasm::kWasmAnyRef);
     module = builder.module();
     // We added one table, therefore table.init on table 0 should work.
     int table_index = 0;
@@ -3373,7 +3323,7 @@ TEST_F(FunctionBodyDecoderTest, TableInitMultiTable) {
     TestModuleBuilder builder;
     builder.AddTable(kWasmAnyRef, 10, true, 20);
     builder.AddTable(kWasmAnyRef, 10, true, 20);
-    builder.AddPassiveElementSegment(wasm::kWasmFuncRef);
+    builder.AddPassiveElementSegment(wasm::kWasmAnyRef);
     module = builder.module();
     // We added two tables, therefore table.init on table 0 should work.
     int table_index = 0;

test/unittests/wasm/module-decoder-unittest.cc

@@ -1324,7 +1324,8 @@ TEST_F(WasmModuleVerifyTest, ElementSectionInitAnyRefTableWithFuncRef) {
       ONE_EMPTY_BODY,
   };
 
-  EXPECT_VERIFIES(data);
+  EXPECT_FAILURE_WITH_MSG(
+      data, "Invalid element segment. Table 0 is not a super-type of funcref");
 }
 
 TEST_F(WasmModuleVerifyTest, ElementSectionDontInitAnyRefImportedTable) {

test/wasm-spec-tests/wasm-spec-tests.status

@@ -23,7 +23,6 @@
   # TODO(v8:10556): Remove sub-typing in the reference-types implementation
   'proposals/bulk-memory-operations/imports': [FAIL],
 
-  'proposals/reference-types/linking': [FAIL],
   'proposals/reference-types/ref_func': [FAIL],
 
   # TODO(wasm): This test declares a table larger than allowed by the spec.