[fuzzer] Add support for the i8 and i16 packed types.

Add support for the i8 and i16 packed types.
Because i8 and i16 do not exist as value types
we need an i32 to instantiate a packed field.

Bug: v8:11954
Change-Id: Ib311fee537c4c9e4aed0ac366172b9b5fb1ee88e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3210267
Commit-Queue: Maria Tîmbur <mtimbur@google.com>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77288}

test/fuzzer/wasm-compile.cc

@@ -104,25 +104,40 @@ bool DataRange::get() {
 }
 
 ValueType GetValueType(DataRange* data, bool liftoff_as_reference,
-                       uint32_t num_types) {
+                       uint32_t num_types, bool include_packed_types = false) {
   constexpr ValueType types[] = {
+      kWasmI8,      kWasmI16,
       kWasmI32,     kWasmI64,
       kWasmF32,     kWasmF64,
       kWasmS128,    kWasmExternRef,
       kWasmFuncRef, kWasmEqRef,
       kWasmAnyRef,  ValueType::Ref(HeapType(HeapType::kData), kNullable)};
+
   constexpr int kLiftoffOnlyTypeCount = 3;  // at the end of {types}.
+  constexpr int kPackedOnlyTypeCount = 2;   // at the begining of {types}.
 
   if (liftoff_as_reference) {
-    uint32_t id = data->get<uint8_t>() % (arraysize(types) + num_types);
+    uint32_t id;
+    if (include_packed_types) {
+      id = data->get<uint8_t>() % (arraysize(types) + num_types);
+    } else {
+      id = kPackedOnlyTypeCount +
+           (data->get<uint8_t>() %
+            (arraysize(types) + num_types - kPackedOnlyTypeCount));
+    }
     if (id >= arraysize(types)) {
       return ValueType::Ref(id - arraysize(types), kNullable);
     }
     return types[id];
   }
-
+  if (include_packed_types) {
     return types[data->get<uint8_t>() %
                  (arraysize(types) - kLiftoffOnlyTypeCount)];
+  }
+  return types[kPackedOnlyTypeCount +
+               (data->get<uint8_t>() %
+                (arraysize(types) - kPackedOnlyTypeCount -
+                 kLiftoffOnlyTypeCount))];
 }
 
 class WasmGenerator {
@@ -820,7 +835,7 @@ class WasmGenerator {
         StructType* struct_gen = builder_->builder()->GetStructType(index);
         int field_count = struct_gen->field_count();
         for (int i = 0; i < field_count; i++) {
-          Generate(struct_gen->field(i), data);
+          Generate(struct_gen->field(i).Unpacked(), data);
         }
         builder_->EmitWithPrefix(kExprRttCanon);
         builder_->EmitU32V(index);
@@ -835,7 +850,8 @@ class WasmGenerator {
         builder_->EmitWithPrefix(kExprArrayNewDefaultWithRtt);
         builder_->EmitU32V(index);
       } else {
-        Generate(builder_->builder()->GetArrayType(index)->element_type(),
+        Generate(
+            builder_->builder()->GetArrayType(index)->element_type().Unpacked(),
             data);
         Generate(kWasmI32, data);
         builder_->EmitWithPrefix(kExprRttCanon);
@@ -942,7 +958,7 @@ class WasmGenerator {
 
     for (uint32_t i = num_structs_; i < num_arrays_ + num_structs_; i++) {
       DCHECK(builder->IsArrayType(i));
-      if (builder->GetArrayType(i)->element_type() == value_type) {
+      if (builder->GetArrayType(i)->element_type().Unpacked() == value_type) {
         array_indices.push_back(i);
       }
     }
@@ -951,7 +967,15 @@ class WasmGenerator {
       int index = data->get<uint8_t>() % static_cast<int>(array_indices.size());
       GenerateOptRef(HeapType(array_indices[index]), data);
       Generate(kWasmI32, data);
+      if (builder->GetArrayType(array_indices[index])
+              ->element_type()
+              .is_packed()) {
+        builder_->EmitWithPrefix(data->get<bool>() ? kExprArrayGetS
+                                                   : kExprArrayGetU);
+
+      } else {
         builder_->EmitWithPrefix(kExprArrayGet);
+      }
       builder_->EmitU32V(array_indices[index]);
       return true;
     }
@@ -1005,7 +1029,9 @@ class WasmGenerator {
     int index = data->get<uint8_t>() % static_cast<int>(array_indices.size());
     GenerateOptRef(HeapType(array_indices[index]), data);
     Generate(kWasmI32, data);
-    Generate(builder->GetArrayType(array_indices[index])->element_type(), data);
+    Generate(
+        builder->GetArrayType(array_indices[index])->element_type().Unpacked(),
+        data);
     builder_->EmitWithPrefix(kExprArraySet);
     builder_->EmitU32V(array_indices[index]);
   }
@@ -1027,7 +1053,14 @@ class WasmGenerator {
     if (!field_index.empty()) {
       int index = data->get<uint8_t>() % static_cast<int>(field_index.size());
       GenerateOptRef(HeapType(struct_index[index]), data);
+      if (builder->GetStructType(struct_index[index])
+              ->field(field_index[index])
+              .is_packed()) {
+        builder_->EmitWithPrefix(data->get<bool>() ? kExprStructGetS
+                                                   : kExprStructGetU);
+      } else {
         builder_->EmitWithPrefix(kExprStructGet);
+      }
       builder_->EmitU32V(struct_index[index]);
       builder_->EmitU32V(field_index[index]);
       return true;
@@ -1070,7 +1103,7 @@ class WasmGenerator {
       int field_index =
           field_indices[data->get<uint8_t>() % field_indices.size()];
       GenerateOptRef(HeapType(struct_index), data);
-      Generate(struct_type->field(field_index), data);
+      Generate(struct_type->field(field_index).Unpacked(), data);
       builder_->EmitWithPrefix(kExprStructSet);
       builder_->EmitU32V(struct_index);
       builder_->EmitU32V(field_index);
@@ -2135,7 +2168,7 @@ class WasmCompileFuzzer : public WasmExecutionFuzzer {
         uint8_t num_fields = range.get<uint8_t>() % (kMaxStructFields + 1);
         StructType::Builder struct_builder(zone, num_fields);
         for (int field_index = 0; field_index < num_fields; field_index++) {
-          ValueType type = GetValueType(&range, true, num_types);
+          ValueType type = GetValueType(&range, true, num_types, true);
           bool mutability = range.get<uint8_t>() < 127;
           struct_builder.AddField(type, mutability);
         }
@@ -2144,7 +2177,7 @@ class WasmCompileFuzzer : public WasmExecutionFuzzer {
       }
 
       for (int array_index = 0; array_index < num_arrays; array_index++) {
-        ValueType type = GetValueType(&range, true, num_types);
+        ValueType type = GetValueType(&range, true, num_types, true);
         ArrayType* array_fuz = zone->New<ArrayType>(type, true);
         builder.AddArrayType(array_fuz);
       }

test/fuzzer/wasm-fuzzer-common.cc

@@ -204,6 +204,10 @@ PrintSig PrintReturns(const FunctionSig* sig) {
 }
 std::string ValueTypeToConstantName(ValueType type) {
   switch (type.kind()) {
+    case kI8:
+      return "kWasmI8";
+    case kI16:
+      return "kWasmI16";
     case kI32:
       return "kWasmI32";
     case kI64: