Reland "[web snapshot] Support numbers"

This is a reland of 7dcc70b8

Original change's description:
> [web snapshot] Support numbers
>
> This CL adds support for integer and double values in web snapshots.
>
> Bug: v8:11525, v8:11706
> Change-Id: Ib75c52d440cd51bf78f57eecca09cecf35b801a4
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2854734
> Commit-Queue: Vicky Kontoura <vkont@google.com>
> Reviewed-by: Camillo Bruni <cbruni@chromium.org>
> Reviewed-by: Marja Hölttä <marja@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#74259}

Bug: v8:11525
Bug: v8:11706
Change-Id: Ia5912ab22db24559c6d0f028a8e744ec448e2250
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2859942Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Vicky Kontoura <vkont@google.com>
Cr-Commit-Position: refs/heads/master@{#74286}

src/objects/value-serializer.cc

@@ -302,6 +302,9 @@ void ValueSerializer::WriteZigZag(T value) {
               (value >> (8 * sizeof(T) - 1)));
 }
 
+template EXPORT_TEMPLATE_DEFINE(
+    V8_EXPORT_PRIVATE) void ValueSerializer::WriteZigZag(int32_t value);
+
 void ValueSerializer::WriteDouble(double value) {
   // Warning: this uses host endianness.
   WriteRawBytes(&value, sizeof(value));
@@ -1215,6 +1218,9 @@ Maybe<T> ValueDeserializer::ReadZigZag() {
                              -static_cast<T>(unsigned_value & 1)));
 }
 
+template EXPORT_TEMPLATE_DEFINE(
+    V8_EXPORT_PRIVATE) Maybe<int32_t> ValueDeserializer::ReadZigZag();
+
 Maybe<double> ValueDeserializer::ReadDouble() {
   // Warning: this uses host endianness.
   if (sizeof(double) > static_cast<unsigned>(end_ - position_))

src/web-snapshot/web-snapshot.cc

@@ -390,8 +390,9 @@ void WebSnapshotSerializer::WriteValue(Handle<Object> object,
                                        ValueSerializer& serializer) {
   uint32_t id = 0;
   if (object->IsSmi()) {
-    // TODO(v8:11525): Implement.
-    UNREACHABLE();
+    serializer.WriteUint32(ValueType::INTEGER);
+    serializer.WriteZigZag<int32_t>(Smi::cast(*object).value());
+    return;
   }
 
   DCHECK(object->IsHeapObject());
@@ -400,8 +401,10 @@ void WebSnapshotSerializer::WriteValue(Handle<Object> object,
       // TODO(v8:11525): Implement.
       UNREACHABLE();
     case HEAP_NUMBER_TYPE:
-      // TODO(v8:11525): Implement.
-      UNREACHABLE();
+      // TODO(v8:11525): Handle possible endianness mismatch.
+      serializer.WriteUint32(ValueType::DOUBLE);
+      serializer.WriteDouble(HeapNumber::cast(*object).value());
+      break;
     case JS_FUNCTION_TYPE:
       SerializeFunction(Handle<JSFunction>::cast(object), id);
       serializer.WriteUint32(ValueType::FUNCTION_ID);
@@ -843,6 +846,26 @@ void WebSnapshotDeserializer::ReadValue(Handle<Object>& value,
     return;
   }
   switch (value_type) {
+    case ValueType::INTEGER: {
+      Maybe<int32_t> number = deserializer_->ReadZigZag<int32_t>();
+      if (number.IsNothing()) {
+        Throw("Web snapshot: Malformed integer");
+        return;
+      }
+      value = isolate_->factory()->NewNumberFromInt(number.FromJust());
+      representation = Representation::Tagged();
+      break;
+    }
+    case ValueType::DOUBLE: {
+      double number;
+      if (!deserializer_->ReadDouble(&number)) {
+        Throw("Web snapshot: Malformed double");
+        return;
+      }
+      value = isolate_->factory()->NewNumber(number);
+      representation = Representation::Tagged();
+      break;
+    }
     case ValueType::STRING_ID: {
       value = ReadString(false);
       representation = Representation::Tagged();

src/web-snapshot/web-snapshot.h

@@ -38,7 +38,13 @@ class WebSnapshotSerializerDeserializer {
   inline bool has_error() const { return error_message_ != nullptr; }
   const char* error_message() const { return error_message_; }
 
-  enum ValueType : uint8_t { STRING_ID, OBJECT_ID, FUNCTION_ID };
+  enum ValueType : uint8_t {
+    INTEGER,
+    DOUBLE,
+    STRING_ID,
+    OBJECT_ID,
+    FUNCTION_ID
+  };
 
   // The maximum count of items for each value type (strings, objects etc.)
   static constexpr uint32_t kMaxItemCount =

test/cctest/test-web-snapshots.cc

@@ -12,10 +12,11 @@ namespace internal {
 
 namespace {
 
-void TestWebSnapshot(const char* snapshot_source, const char* test_source,
-                     const char* expected_result, uint32_t string_count,
-                     uint32_t map_count, uint32_t context_count,
-                     uint32_t function_count, uint32_t object_count) {
+void TestWebSnapshotExtensive(
+    const char* snapshot_source, const char* test_source,
+    std::function<void(v8::Isolate*, v8::Local<v8::Context>)> tester,
+    uint32_t string_count, uint32_t map_count, uint32_t context_count,
+    uint32_t function_count, uint32_t object_count) {
   CcTest::InitializeVM();
   v8::Isolate* isolate = CcTest::isolate();
 
@@ -47,8 +48,7 @@ void TestWebSnapshot(const char* snapshot_source, const char* test_source,
     CHECK(deserializer.UseWebSnapshot(snapshot_data.buffer,
                                       snapshot_data.buffer_size));
     CHECK(!deserializer.has_error());
-    v8::Local<v8::String> result = CompileRun(test_source).As<v8::String>();
-    CHECK(result->Equals(new_context, v8_str(expected_result)).FromJust());
+    tester(isolate, new_context);
     CHECK_EQ(string_count, deserializer.string_count());
     CHECK_EQ(map_count, deserializer.map_count());
     CHECK_EQ(context_count, deserializer.context_count());
@@ -57,6 +57,20 @@ void TestWebSnapshot(const char* snapshot_source, const char* test_source,
   }
 }
 
+void TestWebSnapshot(const char* snapshot_source, const char* test_source,
+                     const char* expected_result, uint32_t string_count,
+                     uint32_t map_count, uint32_t context_count,
+                     uint32_t function_count, uint32_t object_count) {
+  TestWebSnapshotExtensive(
+      snapshot_source, test_source,
+      [test_source, expected_result](v8::Isolate* isolate,
+                                     v8::Local<v8::Context> new_context) {
+        v8::Local<v8::String> result = CompileRun(test_source).As<v8::String>();
+        CHECK(result->Equals(new_context, v8_str(expected_result)).FromJust());
+      },
+      string_count, map_count, context_count, function_count, object_count);
+}
+
 }  // namespace
 
 TEST(Minimal) {
@@ -72,6 +86,60 @@ TEST(Minimal) {
                   kMapCount, kContextCount, kFunctionCount, kObjectCount);
 }
 
+TEST(Numbers) {
+  const char* snapshot_source =
+      "var foo = {'a': 6,\n"
+      "           'b': -11,\n"
+      "           'c': 11.6,\n"
+      "           'd': NaN,\n"
+      "           'e': Number.POSITIVE_INFINITY,\n"
+      "           'f': Number.NEGATIVE_INFINITY,\n"
+      "}";
+  const char* test_source = "foo";
+  uint32_t kStringCount = 7;  // 'foo', 'a', ..., 'f'
+  uint32_t kMapCount = 1;
+  uint32_t kContextCount = 0;
+  uint32_t kFunctionCount = 0;
+  uint32_t kObjectCount = 1;
+  std::function<void(v8::Isolate*, v8::Local<v8::Context>)> tester =
+      [test_source](v8::Isolate* isolate, v8::Local<v8::Context> new_context) {
+        v8::Local<v8::Object> result = CompileRun(test_source).As<v8::Object>();
+        int32_t a = result->Get(new_context, v8_str("a"))
+                        .ToLocalChecked()
+                        .As<v8::Number>()
+                        ->Value();
+        CHECK_EQ(a, 6);
+        int32_t b = result->Get(new_context, v8_str("b"))
+                        .ToLocalChecked()
+                        .As<v8::Number>()
+                        ->Value();
+        CHECK_EQ(b, -11);
+        double c = result->Get(new_context, v8_str("c"))
+                       .ToLocalChecked()
+                       .As<v8::Number>()
+                       ->Value();
+        CHECK_EQ(c, 11.6);
+        double d = result->Get(new_context, v8_str("d"))
+                       .ToLocalChecked()
+                       .As<v8::Number>()
+                       ->Value();
+        CHECK(std::isnan(d));
+        double e = result->Get(new_context, v8_str("e"))
+                       .ToLocalChecked()
+                       .As<v8::Number>()
+                       ->Value();
+        CHECK_EQ(e, std::numeric_limits<double>::infinity());
+        double f = result->Get(new_context, v8_str("f"))
+                       .ToLocalChecked()
+                       .As<v8::Number>()
+                       ->Value();
+        CHECK_EQ(f, -std::numeric_limits<double>::infinity());
+      };
+  TestWebSnapshotExtensive(snapshot_source, test_source, tester, kStringCount,
+                           kMapCount, kContextCount, kFunctionCount,
+                           kObjectCount);
+}
+
 TEST(Function) {
   const char* snapshot_source =
       "var foo = {'key': function() { return '11525'; }};";