[serializer] Remove code object handling from code serializer

R=leszeks@chromium.org

Change-Id: Ib66b36884be7dd1283eb0375cfaf94a5b503f162
Reviewed-on: https://chromium-review.googlesource.com/c/1470110Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59594}

src/snapshot/code-serializer.cc

@@ -127,21 +127,7 @@ void CodeSerializer::SerializeObject(HeapObject obj) {
 
   if (SerializeReadOnlyObject(obj)) return;
 
-  if (obj->IsCode()) {
-    Code code_object = Code::cast(obj);
-    switch (code_object->kind()) {
-      case Code::OPTIMIZED_FUNCTION:  // No optimized code compiled yet.
-      case Code::REGEXP:              // No regexp literals initialized yet.
-      case Code::NUMBER_OF_KINDS:     // Pseudo enum value.
-      case Code::BYTECODE_HANDLER:    // No direct references to handlers.
-        break;                        // hit UNREACHABLE below.
-      case Code::STUB:
-      case Code::BUILTIN:
-      default:
-        return SerializeCodeObject(code_object);
-    }
-    UNREACHABLE();
-  }
+  CHECK(!obj->IsCode());
 
   ReadOnlyRoots roots(isolate());
   if (ElideObject(obj)) {
@@ -328,8 +314,6 @@ SerializedCodeData::SerializedCodeData(const std::vector<byte>* payload,
   SetMagicNumber();
   SetHeaderValue(kVersionHashOffset, Version::Hash());
   SetHeaderValue(kSourceHashOffset, cs->source_hash());
-  SetHeaderValue(kCpuFeaturesOffset,
-                 static_cast<uint32_t>(CpuFeatures::SupportedFeatures()));
   SetHeaderValue(kFlagHashOffset, FlagList::Hash());
   SetHeaderValue(kNumReservationsOffset,
                  static_cast<uint32_t>(reservations.size()));
@@ -359,16 +343,12 @@ SerializedCodeData::SanityCheckResult SerializedCodeData::SanityCheck(
   if (magic_number != kMagicNumber) return MAGIC_NUMBER_MISMATCH;
   uint32_t version_hash = GetHeaderValue(kVersionHashOffset);
   uint32_t source_hash = GetHeaderValue(kSourceHashOffset);
-  uint32_t cpu_features = GetHeaderValue(kCpuFeaturesOffset);
   uint32_t flags_hash = GetHeaderValue(kFlagHashOffset);
   uint32_t payload_length = GetHeaderValue(kPayloadLengthOffset);
   uint32_t c1 = GetHeaderValue(kChecksumPartAOffset);
   uint32_t c2 = GetHeaderValue(kChecksumPartBOffset);
   if (version_hash != Version::Hash()) return VERSION_MISMATCH;
   if (source_hash != expected_source_hash) return SOURCE_MISMATCH;
-  if (cpu_features != static_cast<uint32_t>(CpuFeatures::SupportedFeatures())) {
-    return CPU_FEATURES_MISMATCH;
-  }
   if (flags_hash != FlagList::Hash()) return FLAGS_MISMATCH;
   uint32_t max_payload_length =
       this->size_ -

src/snapshot/code-serializer.h

@@ -58,8 +58,6 @@ class CodeSerializer : public Serializer {
   CodeSerializer(Isolate* isolate, uint32_t source_hash);
   ~CodeSerializer() override { OutputStatistics("CodeSerializer"); }
 
-  virtual void SerializeCodeObject(Code code_object) { UNREACHABLE(); }
-
   virtual bool ElideObject(Object obj) { return false; }
   void SerializeGeneric(HeapObject heap_object);
 
@@ -81,7 +79,6 @@ class SerializedCodeData : public SerializedData {
     MAGIC_NUMBER_MISMATCH = 1,
     VERSION_MISMATCH = 2,
     SOURCE_MISMATCH = 3,
-    CPU_FEATURES_MISMATCH = 4,
     FLAGS_MISMATCH = 5,
     CHECKSUM_MISMATCH = 6,
     INVALID_HEADER = 7,
@@ -92,19 +89,17 @@ class SerializedCodeData : public SerializedData {
   // [0] magic number and (internally provided) external reference count
   // [1] version hash
   // [2] source hash
-  // [3] cpu features
-  // [4] flag hash
-  // [5] number of reservation size entries
-  // [6] payload length
-  // [7] payload checksum part A
-  // [8] payload checksum part B
+  // [3] flag hash
+  // [4] number of reservation size entries
+  // [5] payload length
+  // [6] payload checksum part A
+  // [7] payload checksum part B
   // ...  reservations
   // ...  code stub keys
   // ...  serialized payload
   static const uint32_t kVersionHashOffset = kMagicNumberOffset + kUInt32Size;
   static const uint32_t kSourceHashOffset = kVersionHashOffset + kUInt32Size;
-  static const uint32_t kCpuFeaturesOffset = kSourceHashOffset + kUInt32Size;
-  static const uint32_t kFlagHashOffset = kCpuFeaturesOffset + kUInt32Size;
+  static const uint32_t kFlagHashOffset = kSourceHashOffset + kUInt32Size;
   static const uint32_t kNumReservationsOffset = kFlagHashOffset + kUInt32Size;
   static const uint32_t kPayloadLengthOffset =
       kNumReservationsOffset + kUInt32Size;