[wasm] Remove immediate of ref.is_null

Due to recent spec changes, this CL removes the type immediate of
ref.is_null again. Instead we check if the type of the input parameter
is nullable.

R=jkummerow@chromium.org

Bug: v8:10556
Change-Id: If07d30fe4dd27664be7774422573b2ab2b0dfa20
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2247654
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68484}

src/wasm/function-body-decoder-impl.h

@@ -1487,8 +1487,7 @@ class WasmDecoder : public Decoder {
         return 1 + imm.length;
       }
       case kExprRefIsNull: {
-        RefNullImmediate<validate> imm(WasmFeatures::All(), decoder, pc);
-        return 1 + imm.length;
+        return 1;
       }
       case kExprRefFunc: {
         FunctionIndexImmediate<validate> imm(decoder, pc);
@@ -2424,12 +2423,22 @@ class WasmFullDecoder : public WasmDecoder<validate> {
       }
       case kExprRefIsNull: {
         CHECK_PROTOTYPE_OPCODE(reftypes);
-        RefNullImmediate<validate> imm(this->enabled_, this, this->pc_);
-        if (!this->Validate(this->pc_, imm)) break;
-        Value value = Pop(0, imm.type);
+        Value value = Pop();
         Value* result = Push(kWasmI32);
-        CALL_INTERFACE_IF_REACHABLE(UnOp, opcode, value, result);
-        len = 1 + imm.length;
+        len = 1;
+        if (value.type.is_nullable()) {
+          CALL_INTERFACE_IF_REACHABLE(UnOp, opcode, value, result);
+          break;
+        }
+        if (value.type.is_reference_type()) {
+          // Due to the check above, we know that the value is not null.
+          CALL_INTERFACE_IF_REACHABLE(I32Const, result, 0);
+          break;
+        }
+        this->errorf(this->pc_,
+                     "invalid argument type to ref.is_null. Expected "
+                     "reference type, got %s",
+                     value.type.type_name().c_str());
         break;
       }
       case kExprRefFunc: {

test/cctest/wasm/test-run-wasm-interpreter.cc

@@ -347,21 +347,20 @@ TEST(MemoryGrowInvalidSize) {
 TEST(ReferenceTypeLocals) {
   {
     WasmRunner<int32_t> r(ExecutionTier::kInterpreter);
-    BUILD(r, WASM_REF_IS_NULL(kLocalExternRef, WASM_REF_NULL(kLocalExternRef)));
+    BUILD(r, WASM_REF_IS_NULL(WASM_REF_NULL(kLocalExternRef)));
     CHECK_EQ(1, r.Call());
   }
   {
     WasmRunner<int32_t> r(ExecutionTier::kInterpreter);
     r.AllocateLocal(kWasmExternRef);
-    BUILD(r, WASM_REF_IS_NULL(kLocalExternRef, WASM_GET_LOCAL(0)));
+    BUILD(r, WASM_REF_IS_NULL(WASM_GET_LOCAL(0)));
     CHECK_EQ(1, r.Call());
   }
   {
     WasmRunner<int32_t> r(ExecutionTier::kInterpreter);
     r.AllocateLocal(kWasmExternRef);
     BUILD(r,
-          WASM_REF_IS_NULL(kLocalExternRef,
-                           WASM_TEE_LOCAL(0, WASM_REF_NULL(kLocalExternRef))));
+          WASM_REF_IS_NULL(WASM_TEE_LOCAL(0, WASM_REF_NULL(kLocalExternRef))));
     CHECK_EQ(1, r.Call());
   }
 }

test/common/wasm/wasm-interpreter.cc

@@ -3493,9 +3493,7 @@ class WasmInterpreterInternals {
           SIGN_EXTENSION_CASE(I64SExtendI32, int64_t, int32_t);
 #undef SIGN_EXTENSION_CASE
         case kExprRefIsNull: {
-          RefNullImmediate<Decoder::kNoValidate> imm(WasmFeatures::All(),
-                                                     &decoder, code->at(pc));
-          len = 1 + imm.length;
+          len = 1;
           HandleScope handle_scope(isolate_);  // Avoid leaking handles.
           uint32_t result = Pop().to_externref()->IsNull() ? 1 : 0;
           Push(WasmValue(result));

test/common/wasm/wasm-macro-gen.h

@@ -442,7 +442,7 @@ inline WasmOpcode LoadStoreOpcodeOf(MachineType type, bool store) {
 #define WASM_REF_NULL_GC(type) \
   kExprRefNull, kLocalOptRef, static_cast<byte>(type)
 #define WASM_REF_FUNC(val) kExprRefFunc, val
-#define WASM_REF_IS_NULL(type, val) val, kExprRefIsNull, static_cast<byte>(type)
+#define WASM_REF_IS_NULL(val) val, kExprRefIsNull
 #define WASM_REF_AS_NON_NULL(val) val, kExprRefAsNonNull
 #define WASM_REF_EQ(lhs, rhs) lhs, rhs, kExprRefEq
 

test/debugger/debug/wasm/debug-enabled-tier-down-wasm-unsupported-liftoff.js

@@ -14,7 +14,7 @@ function create_builder(i) {
   const builder = new WasmModuleBuilder();
   builder.addFunction('main', kSig_i_r)
       .addBody([
-        kExprLocalGet, 0, kExprRefIsNull, kWasmExternRef, ...wasmI32Const(i),
+        kExprLocalGet, 0, kExprRefIsNull, ...wasmI32Const(i),
         kExprI32Add
       ])
       .exportFunc();

test/mjsunit/regress/wasm/regress-7785.js

@@ -24,7 +24,7 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
 (function testExternRefIsNull() {
   const builder = new WasmModuleBuilder();
   builder.addFunction('main', kSig_i_r)
-      .addBody([kExprLocalGet, 0, kExprRefIsNull, kWasmExternRef])
+      .addBody([kExprLocalGet, 0, kExprRefIsNull])
       .exportFunc();
 
   var wire_bytes = builder.toBuffer();

test/mjsunit/wasm/exceptions-externref.js

@@ -43,7 +43,7 @@ load("test/mjsunit/wasm/exceptions-utils.js");
           kExprBrOnExn, 0, except,
           kExprRethrow,
         kExprEnd,
-        kExprRefIsNull, kWasmExternRef,
+        kExprRefIsNull,
         kExprIf, kWasmI32,
           kExprI32Const, 23,
         kExprElse,

test/mjsunit/wasm/externref.js

@@ -177,7 +177,7 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
   print(arguments.callee.name);
   const builder = new WasmModuleBuilder();
   builder.addFunction('main', kSig_i_r)
-      .addBody([kExprLocalGet, 0, kExprRefIsNull, kWasmExternRef])
+      .addBody([kExprLocalGet, 0, kExprRefIsNull])
       .exportFunc();
 
   const instance = builder.instantiate();
@@ -196,10 +196,7 @@ load("test/mjsunit/wasm/wasm-module-builder.js");
 
   const builder = new WasmModuleBuilder();
   builder.addFunction('main', kSig_i_v)
-      .addBody([
-        kExprRefNull, kWasmExternRef,   // --
-        kExprRefIsNull, kWasmExternRef  // --
-      ])
+      .addBody([kExprRefNull, kWasmExternRef, kExprRefIsNull])
       .exportFunc();
 
   const instance = builder.instantiate();

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

@@ -2976,6 +2976,15 @@ TEST_F(FunctionBodyDecoderTest, IfParam) {
                    WASM_I32_ADD(WASM_NOP, WASM_NOP)});
 }
 
+TEST_F(FunctionBodyDecoderTest, RefIsNull) {
+  WASM_FEATURE_SCOPE(reftypes);
+  ExpectValidates(sigs.i_i(),
+                  {WASM_REF_IS_NULL(WASM_REF_NULL(kLocalExternRef))});
+  ExpectFailure(
+      sigs.i_i(), {WASM_REF_IS_NULL(WASM_GET_LOCAL(0))}, kAppendEnd,
+      "invalid argument type to ref.is_null. Expected reference type, got i32");
+}
+
 TEST_F(FunctionBodyDecoderTest, Regression709741) {
   AddLocals(kWasmI32, kV8MaxWasmFunctionLocals - 1);
   ExpectValidates(sigs.v_v(), {WASM_NOP});

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

@@ -4,13 +4,6 @@
 
 [
 [ALWAYS, {
-  # TODO(v8:10556): Remove sub-typing in the reference-types implementation
-  'proposals/reference-types/table_grow': [FAIL],
-  'proposals/reference-types/table_set': [FAIL],
-  'proposals/reference-types/table_get': [FAIL],
-  'proposals/reference-types/ref_is_null': [FAIL],
-  'proposals/reference-types/ref_func': [FAIL],
-
   #TODO(ahaas): Add additional stack checks on mips.
   'skip-stack-guard-page': [PASS, ['arch == mipsel or arch == mips64el or ((arch == ppc or arch == ppc64 or arch == s390 or arch == s390x) and simulator_run)', SKIP]],