[wasm][anyref] Support decoding of signatures with AnyFunc

With this CL we now also support the decoding of the AnyFunc
type. I will add the type more deeply in subsequent CLs.

R=titzer@chromium.org

Bug: v8:7581
Change-Id: I9f30706a442462f915adfd8f720eb65168b80bb8
Reviewed-on: https://chromium-review.googlesource.com/1014111
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54318}

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

@@ -248,6 +248,9 @@ struct BlockTypeImmediate {
       case kLocalS128:
         *result = kWasmS128;
         return true;
+      case kLocalAnyFunc:
+        *result = kWasmAnyFunc;
+        return true;
       case kLocalAnyRef:
         *result = kWasmAnyRef;
         return true;

src/wasm/module-decoder.cc

@@ -1280,6 +1280,9 @@ class ModuleDecoderImpl : public Decoder {
             case kLocalS128:
               if (FLAG_experimental_wasm_simd) return kWasmS128;
               break;
+            case kLocalAnyFunc:
+              if (FLAG_experimental_wasm_anyref) return kWasmAnyFunc;
+              break;
             case kLocalAnyRef:
               if (FLAG_experimental_wasm_anyref) return kWasmAnyRef;
               break;

src/wasm/value-type.h

@@ -20,6 +20,7 @@ enum ValueType : uint8_t {
   kWasmF64,
   kWasmS128,
   kWasmAnyRef,
+  kWasmAnyFunc,
   kWasmVar,
 };
 
@@ -234,6 +235,7 @@ class V8_EXPORT_PRIVATE ValueTypes {
         return MachineType::Float32();
       case kWasmF64:
         return MachineType::Float64();
+      case kWasmAnyFunc:
       case kWasmAnyRef:
         return MachineType::TaggedPointer();
       case kWasmS128:

src/wasm/wasm-constants.h

@@ -21,6 +21,7 @@ enum ValueTypeCode : uint8_t {
   kLocalF32 = 0x7d,
   kLocalF64 = 0x7c,
   kLocalS128 = 0x7b,
+  kLocalAnyFunc = 0x70,
   kLocalAnyRef = 0x6f
 };
 // Binary encoding of other types.

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

@@ -135,11 +135,14 @@ static size_t SizeOfVarInt(size_t value) {
 struct ValueTypePair {
   uint8_t code;
   ValueType type;
-} kValueTypes[] = {{kLocalI32, kWasmI32},
-                   {kLocalI64, kWasmI64},
-                   {kLocalF32, kWasmF32},
-                   {kLocalF64, kWasmF64},
-                   {kLocalAnyRef, kWasmAnyRef}};
+} kValueTypes[] = {
+    {kLocalI32, kWasmI32},          // --
+    {kLocalI64, kWasmI64},          // --
+    {kLocalF32, kWasmF32},          // --
+    {kLocalF64, kWasmF64},          // --
+    {kLocalAnyFunc, kWasmAnyFunc},  // --
+    {kLocalAnyRef, kWasmAnyRef}     // --
+};
 
 class WasmModuleVerifyTest : public TestWithIsolateAndZone {
  public:
@@ -1086,14 +1089,16 @@ 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;
+  byte ref_types[] = {kLocalAnyFunc, kLocalAnyRef};
+  for (byte invalid_type : ref_types) {
     for (size_t i = 0; i < SIZEOF_SIG_ENTRY_x_xx; i++) {
       byte data[] = {SIG_ENTRY_x_xx(kLocalI32, kLocalI32, kLocalI32)};
-    data[i] = kInvalidType;
+      data[i] = invalid_type;
       FunctionSig* sig =
           DecodeWasmSignatureForTesting(zone(), data, data + sizeof(data));
       EXPECT_EQ(nullptr, sig);
     }
+  }
 }
 
 TEST_F(WasmSignatureDecodeTest, Fail_invalid_type) {