[wasm][anyref] Add support for AnyRef in signature decoding

R=titzer@chromium.org

Bug: v8:7581
Change-Id: I51c585aafa71cbc20565974929cba8327d7f8427
Reviewed-on: https://chromium-review.googlesource.com/973305
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52133}

src/flag-definitions.h

@@ -588,6 +588,8 @@ DEFINE_BOOL(experimental_wasm_sat_f2i_conversions, false,
             "enable non-trapping float-to-int conversions for wasm")
 DEFINE_BOOL(experimental_wasm_se, false,
             "enable prototype sign extension opcodes for wasm")
+DEFINE_BOOL(experimental_wasm_anyref, false,
+            "enable prototype anyref support for wasm")
 
 DEFINE_BOOL(wasm_opt, false, "enable wasm optimization")
 DEFINE_BOOL(wasm_no_bounds_checks, false,

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

@@ -241,6 +241,9 @@ struct BlockTypeOperand {
       case kLocalS128:
         *result = kWasmS128;
         return true;
+      case kLocalAnyRef:
+        *result = kWasmAnyRef;
+        return true;
       default:
         *result = kWasmVar;
         return false;

src/wasm/module-decoder.cc

@@ -1244,10 +1244,14 @@ class ModuleDecoderImpl : public Decoder {
       case kLocalF64:
         return kWasmF64;
       default:
-        if (IsWasm() && FLAG_experimental_wasm_simd) {
+        if (IsWasm()) {
           switch (t) {
             case kLocalS128:
-              return kWasmS128;
+              if (FLAG_experimental_wasm_simd) return kWasmS128;
+              break;
+            case kLocalAnyRef:
+              if (FLAG_experimental_wasm_anyref) return kWasmAnyRef;
+              break;
             default:
               break;
           }

src/wasm/wasm-constants.h

@@ -20,7 +20,8 @@ enum ValueTypeCode : uint8_t {
   kLocalI64 = 0x7e,
   kLocalF32 = 0x7d,
   kLocalF64 = 0x7c,
-  kLocalS128 = 0x7b
+  kLocalS128 = 0x7b,
+  kLocalAnyRef = 0x6f
 };
 // Binary encoding of other types.
 constexpr uint8_t kWasmFunctionTypeCode = 0x60;

src/wasm/wasm-opcodes.h

@@ -23,6 +23,7 @@ constexpr ValueType kWasmI32 = MachineRepresentation::kWord32;
 constexpr ValueType kWasmI64 = MachineRepresentation::kWord64;
 constexpr ValueType kWasmF32 = MachineRepresentation::kFloat32;
 constexpr ValueType kWasmF64 = MachineRepresentation::kFloat64;
+constexpr ValueType kWasmAnyRef = MachineRepresentation::kTaggedPointer;
 constexpr ValueType kWasmS128 = MachineRepresentation::kSimd128;
 constexpr ValueType kWasmVar = MachineRepresentation::kTagged;
 
@@ -749,6 +750,8 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
         return kLocalF64;
       case kWasmS128:
         return kLocalS128;
+      case kWasmAnyRef:
+        return kLocalAnyRef;
       case kWasmStmt:
         return kLocalVoid;
       default:

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

@@ -137,7 +137,8 @@ struct ValueTypePair {
 } kValueTypes[] = {{kLocalI32, kWasmI32},
                    {kLocalI64, kWasmI64},
                    {kLocalF32, kWasmF32},
-                   {kLocalF64, kWasmF64}};
+                   {kLocalF64, kWasmF64},
+                   {kLocalAnyRef, kWasmAnyRef}};
 
 class WasmModuleVerifyTest : public TestWithIsolateAndZone {
  public:
@@ -894,7 +895,17 @@ TEST_F(WasmModuleVerifyTest, IndirectFunctionInvalidIndex) {
   EXPECT_FAILURE(data);
 }
 
-class WasmSignatureDecodeTest : public TestWithZone {};
+class WasmSignatureDecodeTest : public TestWithZone {
+ public:
+  WasmSignatureDecodeTest()
+      // In the following tests we turn on support for AnyRef by default. There
+      // is a test (Fail_anyref_without_flag) which explicitly turns off support
+      // for AnyRef.
+      : flag_scope(&FLAG_experimental_wasm_anyref, true) {}
+
+ private:
+  FlagScope<bool> flag_scope;
+};
 
 TEST_F(WasmSignatureDecodeTest, Ok_v_v) {
   static const byte data[] = {SIG_ENTRY_v_v};
@@ -1010,6 +1021,19 @@ TEST_F(WasmSignatureDecodeTest, Fail_off_end) {
   }
 }
 
+TEST_F(WasmSignatureDecodeTest, Fail_anyref_without_flag) {
+  // Disable AnyRef support and check that decoding fails.
+  FlagScope<bool> flag_scope(&FLAG_experimental_wasm_anyref, false);
+  byte kInvalidType = kLocalAnyRef;
+  for (size_t i = 0; i < SIZEOF_SIG_ENTRY_x_xx; i++) {
+    byte data[] = {SIG_ENTRY_x_xx(kLocalI32, kLocalI32, kLocalI32)};
+    data[i] = kInvalidType;
+    FunctionSig* sig =
+        DecodeWasmSignatureForTesting(zone(), data, data + sizeof(data));
+    EXPECT_EQ(nullptr, sig);
+  }
+}
+
 TEST_F(WasmSignatureDecodeTest, Fail_invalid_type) {
   byte kInvalidType = 76;
   for (size_t i = 0; i < SIZEOF_SIG_ENTRY_x_xx; i++) {