Implement patch records to patch canonical objects.

runtime/vm/raw_object_snapshot.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/snapshot.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/visitor.h"
 
 namespace dart {
 
 #define NEW_OBJECT(type)                                                       \
   ((kind == Snapshot::kFull) ? reader->New##type() : type::New())
 
 #define NEW_OBJECT_WITH_LEN(type, len)                                         \
   ((kind == Snapshot::kFull) ? reader->New##type(len) : type::New(len))
 
 #define NEW_OBJECT_WITH_LEN_SPACE(type, len, kind)                             \
   ((kind == Snapshot::kFull) ?                                                 \
   reader->New##type(len) : type::New(len, HEAP_SPACE(kind)))
 
+#define OFFSET_OF_FROM(obj)                                                    \
+  obj.raw()->from() - reinterpret_cast<RawObject**>(obj.raw()->ptr())
 
 RawClass* Class::ReadFrom(SnapshotReader* reader,
                           intptr_t object_id,
                           intptr_t tags,
                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   Class& cls = Class::ZoneHandle(reader->zone(), Class::null());
   if ((kind == Snapshot::kFull) ||
       (kind == Snapshot::kScript && !RawObject::IsCreatedFromSnapshot(tags))) {
@@ skipping 26 matching lines @@
     cls.set_num_type_arguments(reader->Read<int16_t>());
     cls.set_num_own_type_arguments(reader->Read<int16_t>());
     cls.set_num_native_fields(reader->Read<uint16_t>());
     cls.set_token_pos(reader->Read<int32_t>());
     cls.set_state_bits(reader->Read<uint16_t>());
 
     // Set all the object fields.
     // TODO(5411462): Need to assert No GC can happen here, even though
     // allocations may happen.
     intptr_t num_flds = (cls.raw()->to() - cls.raw()->from());
+    intptr_t from_offset = OFFSET_OF_FROM(cls);
     for (intptr_t i = 0; i <= num_flds; i++) {
-      (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
-       cls.StorePointer((cls.raw()->from() + i),
+      (*reader->PassiveObjectHandle()) =
+          reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
+      cls.StorePointer((cls.raw()->from() + i),
                        reader->PassiveObjectHandle()->raw());
     }
   } else {
     cls ^= reader->ReadClassId(object_id);
   }
   return cls.raw();
 }
 
 
 void RawClass::WriteTo(SnapshotWriter* writer,
@@ skipping 115 matching lines @@
 
 
 RawType* Type::ReadFrom(SnapshotReader* reader,
                         intptr_t object_id,
                         intptr_t tags,
                         Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Allocate type object.
   Type& type = Type::ZoneHandle(reader->zone(), NEW_OBJECT(Type));
-  reader->AddBackRef(object_id, &type, kIsDeserialized);
+  bool is_canonical = RawObject::IsCanonical(tags);
+  bool defer_canonicalization = is_canonical && (kind != Snapshot::kFull);
+  reader->AddBackRef(object_id, &type, kIsDeserialized, defer_canonicalization);
 
   // Set all non object fields.
   type.set_token_pos(reader->Read<int32_t>());
   type.set_type_state(reader->Read<int8_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (type.raw()->to() - type.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(type);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsInlinedObject);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsInlinedObject, object_id, (i + from_offset));
     type.StorePointer((type.raw()->from() + i),
                       reader->PassiveObjectHandle()->raw());
   }
 
-  // If object needs to be a canonical object, Canonicalize it.
-  // When reading a full snapshot we don't need to canonicalize the object
-  // as it would already be a canonical object.
-  // When reading a script snapshot we need to canonicalize only those object
-  // references that are objects from the core library (loaded from a
-  // full snapshot). Objects that are only in the script need not be
-  // canonicalized as they are already canonical.
-  // When reading a message snapshot we always have to canonicalize the object.
-  if ((kind != Snapshot::kFull) && RawObject::IsCanonical(tags) &&
-      (RawObject::IsCreatedFromSnapshot(tags) ||
-       (kind == Snapshot::kMessage))) {
-    type ^= type.Canonicalize();
-  }
-
-  // Set the object tags (This is done after 'Canonicalize', which
-  // does not canonicalize a type already marked as canonical).
+  // Set the object tags.
   type.set_tags(tags);
 
   return type.raw();
 }
 
 
 void RawType::WriteTo(SnapshotWriter* writer,
                       intptr_t object_id,
                       Snapshot::Kind kind) {
   ASSERT(writer != NULL);
@@ skipping 32 matching lines @@
       reader->zone(), NEW_OBJECT(TypeRef));
   reader->AddBackRef(object_id, &type_ref, kIsDeserialized);
 
   // Set the object tags.
   type_ref.set_tags(tags);
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (type_ref.raw()->to() - type_ref.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(type_ref);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     type_ref.StorePointer((type_ref.raw()->from() + i),
                           reader->PassiveObjectHandle()->raw());
   }
 
   return type_ref.raw();
 }
 
 
 void RawTypeRef::WriteTo(SnapshotWriter* writer,
                          intptr_t object_id,
@@ skipping 30 matching lines @@
   // Set all non object fields.
   type_parameter.set_token_pos(reader->Read<int32_t>());
   type_parameter.set_index(reader->Read<int16_t>());
   type_parameter.set_type_state(reader->Read<int8_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (type_parameter.raw()->to() -
                        type_parameter.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(type_parameter);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     type_parameter.StorePointer((type_parameter.raw()->from() + i),
                                 reader->PassiveObjectHandle()->raw());
   }
 
   return type_parameter.raw();
 }
 
 
 void RawTypeParameter::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
@@ skipping 33 matching lines @@
   reader->AddBackRef(object_id, &bounded_type, kIsDeserialized);
 
   // Set the object tags.
   bounded_type.set_tags(tags);
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (bounded_type.raw()->to() -
                        bounded_type.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(bounded_type);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     bounded_type.StorePointer((bounded_type.raw()->from() + i),
                               reader->PassiveObjectHandle()->raw());
   }
 
   return bounded_type.raw();
 }
 
 
 void RawBoundedType::WriteTo(SnapshotWriter* writer,
                              intptr_t object_id,
@@ skipping 33 matching lines @@
                                           intptr_t object_id,
                                           intptr_t tags,
                                           Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Read the length so that we can determine instance size to allocate.
   intptr_t len = reader->ReadSmiValue();
 
   TypeArguments& type_arguments = TypeArguments::ZoneHandle(
       reader->zone(), NEW_OBJECT_WITH_LEN_SPACE(TypeArguments, len, kind));
-  reader->AddBackRef(object_id, &type_arguments, kIsDeserialized);
+  bool is_canonical = RawObject::IsCanonical(tags);
+  bool defer_canonicalization = is_canonical && (kind != Snapshot::kFull);
+  reader->AddBackRef(object_id,
+                     &type_arguments,
+                     kIsDeserialized,
+                     defer_canonicalization);
 
   // Set the instantiations field, which is only read from a full snapshot.
   if (kind == Snapshot::kFull) {
     *(reader->ArrayHandle()) ^= reader->ReadObjectImpl(kAsInlinedObject);
     type_arguments.set_instantiations(*(reader->ArrayHandle()));
   } else {
     type_arguments.set_instantiations(Object::zero_array());
   }
 
   // Now set all the type fields.
+  intptr_t offset = type_arguments.TypeAddr(0) -
+      reinterpret_cast<RawAbstractType**>(type_arguments.raw()->ptr());
   for (intptr_t i = 0; i < len; i++) {
-    *reader->TypeHandle() ^= reader->ReadObjectImpl(kAsInlinedObject);
+    *reader->TypeHandle() ^=
+        reader->ReadObjectImpl(kAsInlinedObject, object_id, (i + offset));
     type_arguments.SetTypeAt(i, *reader->TypeHandle());
   }
 
-  // If object needs to be a canonical object, Canonicalize it.
-  // When reading a full snapshot we don't need to canonicalize the object
-  // as it would already be a canonical object.
-  // When reading a script snapshot we need to canonicalize only those object
-  // references that are objects from the core library (loaded from a
-  // full snapshot). Objects that are only in the script need not be
-  // canonicalized as they are already canonical.
-  // When reading a message snapshot we always have to canonicalize the object.
-  if ((kind != Snapshot::kFull) && RawObject::IsCanonical(tags) &&
-      (RawObject::IsCreatedFromSnapshot(tags) ||
-       (kind == Snapshot::kMessage))) {
-    type_arguments ^= type_arguments.Canonicalize();
-  }
-
-  // Set the object tags (This is done after setting the object fields
-  // because 'SetTypeAt' has an assertion to check if the object is not
-  // already canonical. Also, this is done after 'Canonicalize', which
-  // does not canonicalize a type already marked as canonical).
+  // Set the object tags .
   type_arguments.set_tags(tags);
 
   return type_arguments.raw();
 }
 
 
 void RawTypeArguments::WriteTo(SnapshotWriter* writer,
                                intptr_t object_id,
                                Snapshot::Kind kind) {
   ASSERT(writer != NULL);
@@ skipping 146 matching lines @@
       reader->zone(), NEW_OBJECT(RedirectionData));
   reader->AddBackRef(object_id, &data, kIsDeserialized);
 
   // Set the object tags.
   data.set_tags(tags);
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (data.raw()->to() - data.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(data);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     data.StorePointer((data.raw()->from() + i),
                       reader->PassiveObjectHandle()->raw());
   }
 
   return data.raw();
 }
 
 
 void RawRedirectionData::WriteTo(SnapshotWriter* writer,
                                  intptr_t object_id,
@@ skipping 42 matching lines @@
   func.set_deoptimization_counter(reader->Read<int16_t>());
   func.set_regexp_cid(reader->ReadClassIDValue());
   func.set_kind_tag(reader->Read<uint32_t>());
   func.set_optimized_instruction_count(reader->Read<uint16_t>());
   func.set_optimized_call_site_count(reader->Read<uint16_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (func.raw()->to_snapshot() - func.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(func);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     func.StorePointer((func.raw()->from() + i),
                       reader->PassiveObjectHandle()->raw());
   }
 
   // Initialize all fields that are not part of the snapshot.
   func.ClearICDataArray();
   func.ClearCode();
   return func.raw();
 }
 
@@ skipping 50 matching lines @@
   // Set all non object fields.
   field.set_token_pos(reader->Read<int32_t>());
   field.set_guarded_cid(reader->Read<int32_t>());
   field.set_is_nullable(reader->Read<int32_t>());
   field.set_kind_bits(reader->Read<uint8_t>());
 
   // Set all the object fields.
   // TODO(5411462): Need to assert No GC can happen here, even though
   // allocations may happen.
   intptr_t num_flds = (field.raw()->to() - field.raw()->from());
+  intptr_t from_offset = OFFSET_OF_FROM(field);
   for (intptr_t i = 0; i <= num_flds; i++) {
-    (*reader->PassiveObjectHandle()) = reader->ReadObjectImpl(kAsReference);
+    (*reader->PassiveObjectHandle()) =
+        reader->ReadObjectImpl(kAsReference, object_id, (i + from_offset));
     field.StorePointer((field.raw()->from() + i),
                        reader->PassiveObjectHandle()->raw());
   }
 
   field.InitializeGuardedListLengthInObjectOffset();
 
   return field.raw();
 }
 
 
@@ skipping 1455 matching lines @@
   // Read the length so that we can determine instance size to allocate.
   intptr_t len = reader->ReadSmiValue();
   Array* array = reinterpret_cast<Array*>(
       reader->GetBackRef(object_id));
   if (array == NULL) {
     array = &(Array::ZoneHandle(reader->zone(),
                                 NEW_OBJECT_WITH_LEN_SPACE(Array, len, kind)));
     reader->AddBackRef(object_id, array, kIsDeserialized);
   }
   ASSERT(!RawObject::IsCanonical(tags));
-  reader->ArrayReadFrom(*array, len, tags);
+  reader->ArrayReadFrom(object_id, *array, len, tags);
   return array->raw();
 }
 
 
 RawImmutableArray* ImmutableArray::ReadFrom(SnapshotReader* reader,
                                             intptr_t object_id,
                                             intptr_t tags,
                                             Snapshot::Kind kind) {
   ASSERT(reader != NULL);
 
   // Read the length so that we can determine instance size to allocate.
   intptr_t len = reader->ReadSmiValue();
   Array* array = reinterpret_cast<Array*>(reader->GetBackRef(object_id));
   if (array == NULL) {
     array = &(Array::ZoneHandle(
         reader->zone(),
         NEW_OBJECT_WITH_LEN_SPACE(ImmutableArray, len, kind)));
     reader->AddBackRef(object_id, array, kIsDeserialized);
   }
-  reader->ArrayReadFrom(*array, len, tags);
+  reader->ArrayReadFrom(object_id, *array, len, tags);
   if (RawObject::IsCanonical(tags)) {
     *array ^= array->CheckAndCanonicalize(NULL);
   }
   return raw(*array);
 }
 
 
 void RawArray::WriteTo(SnapshotWriter* writer,
                        intptr_t object_id,
                        Snapshot::Kind kind) {
@@ skipping 78 matching lines @@
     UNREACHABLE();
   } else {
     // Since the map might contain itself as a key or value, allocate first.
     map = LinkedHashMap::NewUninitialized(HEAP_SPACE(kind));
   }
   reader->AddBackRef(object_id, &map, kIsDeserialized);
   // Set the object tags.
   map.set_tags(tags);
 
   // Read the type arguments.
-  *reader->TypeArgumentsHandle() ^= reader->ReadObjectImpl(kAsInlinedObject);
+  intptr_t typeargs_offset =
+      reinterpret_cast<RawObject**>(&map.raw()->ptr()->type_arguments_) -
+      reinterpret_cast<RawObject**>(map.raw()->ptr());
+  *reader->TypeArgumentsHandle() ^=
+      reader->ReadObjectImpl(kAsInlinedObject, object_id, typeargs_offset);
   map.SetTypeArguments(*reader->TypeArgumentsHandle());
 
   // Read the number of key/value pairs.
   intptr_t len = reader->ReadSmiValue();
   intptr_t used_data = (len << 1);
   map.SetUsedData(used_data);
 
   // Allocate the data array.
   intptr_t data_size = Utils::Maximum(
       Utils::RoundUpToPowerOfTwo(used_data),
@@ skipping 273 matching lines @@
 
 
 RawExternalTypedData* ExternalTypedData::ReadFrom(SnapshotReader* reader,
                                                   intptr_t object_id,
                                                   intptr_t tags,
                                                   Snapshot::Kind kind) {
   ASSERT(kind != Snapshot::kFull);
   intptr_t cid = RawObject::ClassIdTag::decode(tags);
   intptr_t length = reader->ReadSmiValue();
   uint8_t* data = reinterpret_cast<uint8_t*>(reader->ReadRawPointerValue());
-  const ExternalTypedData& obj = ExternalTypedData::Handle(
+  ExternalTypedData& obj = ExternalTypedData::Handle(
       ExternalTypedData::New(cid, data, length));
+  reader->AddBackRef(object_id, &obj, kIsDeserialized);
   void* peer = reinterpret_cast<void*>(reader->ReadRawPointerValue());
   Dart_WeakPersistentHandleFinalizer callback =
       reinterpret_cast<Dart_WeakPersistentHandleFinalizer>(
           reader->ReadRawPointerValue());
   obj.AddFinalizer(peer, callback);
   return obj.raw();
 }
 
 
 #define TYPED_DATA_WRITE(type)                                                 \
@@ skipping 405 matching lines @@
     // We do not allow objects with native fields in an isolate message.
     writer->SetWriteException(Exceptions::kArgument,
                               "Illegal argument in isolate message"
                               " : (object is a UserTag)");
   } else {
     UNREACHABLE();
   }
 }
 
 }  // namespace dart