[snapshot] remove support for deoptimization entries.

We no longer include hydrogen stubs in the snapshot.

R=jgruber@chromium.org

Change-Id: Id268b416ed839f55d297a1888444ef6323ec9dd9
Reviewed-on: https://chromium-review.googlesource.com/631956Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47570}

src/snapshot/deserializer.cc

@@ -483,33 +483,6 @@ bool Deserializer::ReadData(Object** current, Object** limit, int source_space,
         break;
       }
 
-      case kDeoptimizerEntryFromCode:
-      case kDeoptimizerEntryPlain: {
-        int skip = source_.GetInt();
-        current = reinterpret_cast<Object**>(
-            reinterpret_cast<intptr_t>(current) + skip);
-        Deoptimizer::BailoutType bailout_type =
-            static_cast<Deoptimizer::BailoutType>(source_.Get());
-        int entry_id = source_.GetInt();
-        HandleScope scope(isolate);
-        Address address = Deoptimizer::GetDeoptimizationEntry(
-            isolate_, entry_id, bailout_type, Deoptimizer::ENSURE_ENTRY_CODE);
-        if (data == kDeoptimizerEntryFromCode) {
-          Address location_of_branch_data = reinterpret_cast<Address>(current);
-          Assembler::deserialization_set_special_target_at(
-              isolate, location_of_branch_data,
-              Code::cast(HeapObject::FromAddress(current_object_address)),
-              address);
-          location_of_branch_data += Assembler::kSpecialTargetSize;
-          current = reinterpret_cast<Object**>(location_of_branch_data);
-        } else {
-          Object* new_object = reinterpret_cast<Object*>(address);
-          UnalignedCopy(current, &new_object);
-          current++;
-        }
-        break;
-      }
-
       case kInternalReferenceEncoded:
       case kInternalReference: {
         // Internal reference address is not encoded via skip, but by offset

src/snapshot/serializer.cc

@@ -353,25 +353,6 @@ bool Serializer::HasNotExceededFirstPageOfEachSpace() {
   return true;
 }
 
-bool Serializer::ObjectSerializer::TryEncodeDeoptimizationEntry(
-    HowToCode how_to_code, Address target, int skip) {
-  for (int bailout_type = 0; bailout_type <= Deoptimizer::kLastBailoutType;
-       ++bailout_type) {
-    int id = Deoptimizer::GetDeoptimizationId(
-        serializer_->isolate(), target,
-        static_cast<Deoptimizer::BailoutType>(bailout_type));
-    if (id == Deoptimizer::kNotDeoptimizationEntry) continue;
-    sink_->Put(how_to_code == kPlain ? kDeoptimizerEntryPlain
-                                     : kDeoptimizerEntryFromCode,
-               "DeoptimizationEntry");
-    sink_->PutInt(skip, "SkipB4DeoptimizationEntry");
-    sink_->Put(bailout_type, "BailoutType");
-    sink_->PutInt(id, "EntryId");
-    return true;
-  }
-  return false;
-}
-
 void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
                                                      int size, Map* map) {
   if (serializer_->code_address_map_) {
@@ -746,11 +727,9 @@ void Serializer::ObjectSerializer::VisitExternalReference(Foreign* host,
   int skip = OutputRawData(reinterpret_cast<Address>(p),
                            kCanReturnSkipInsteadOfSkipping);
   Address target = *p;
-  if (!TryEncodeDeoptimizationEntry(kPlain, target, skip)) {
   sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
   sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
-  }
   bytes_processed_so_far_ += kPointerSize;
 }
 
@@ -760,13 +739,10 @@ void Serializer::ObjectSerializer::VisitExternalReference(Code* host,
                            kCanReturnSkipInsteadOfSkipping);
   HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
   Address target = rinfo->target_external_reference();
-  if (!TryEncodeDeoptimizationEntry(how_to_code, target, skip)) {
-    sink_->Put(kExternalReference + how_to_code + kStartOfObject,
-               "ExternalRef");
+  sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
   DCHECK_NOT_NULL(target);  // Code does not reference null.
   sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
-  }
   bytes_processed_so_far_ += rinfo->target_address_size();
 }
 
@@ -801,12 +777,9 @@ void Serializer::ObjectSerializer::VisitRuntimeEntry(Code* host,
                            kCanReturnSkipInsteadOfSkipping);
   HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
   Address target = rinfo->target_address();
-  if (!TryEncodeDeoptimizationEntry(how_to_code, target, skip)) {
-    sink_->Put(kExternalReference + how_to_code + kStartOfObject,
-               "ExternalRef");
+  sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
   sink_->PutInt(skip, "SkipB4ExternalRef");
   sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
-  }
   bytes_processed_so_far_ += rinfo->target_address_size();
 }
 

src/snapshot/serializer.h

@@ -321,8 +321,6 @@ class Serializer::ObjectSerializer : public ObjectVisitor {
   void VisitRuntimeEntry(Code* host, RelocInfo* reloc) override;
 
  private:
-  bool TryEncodeDeoptimizationEntry(HowToCode how_to_code, Address target,
-                                    int skip);
   void SerializePrologue(AllocationSpace space, int size, Map* map);