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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <ctime>
#include "object.h"
#include "art_field.h"
#include "art_field-inl.h"
#include "array-inl.h"
#include "class.h"
#include "class-inl.h"
#include "class_linker-inl.h"
#include "gc/accounting/card_table-inl.h"
#include "gc/heap.h"
#include "iftable-inl.h"
#include "monitor.h"
#include "object-inl.h"
#include "object_array-inl.h"
#include "object_utils.h"
#include "runtime.h"
#include "sirt_ref.h"
#include "throwable.h"
#include "well_known_classes.h"
namespace art {
namespace mirror {
Object* Object::Clone(Thread* self) {
Class* c = GetClass();
DCHECK(!c->IsClassClass());
// Object::SizeOf gets the right size even if we're an array.
// Using c->AllocObject() here would be wrong.
size_t num_bytes = SizeOf();
gc::Heap* heap = Runtime::Current()->GetHeap();
SirtRef<Object> copy(self, heap->AllocObject(self, c, num_bytes));
if (copy.get() == NULL) {
return NULL;
}
// Copy instance data. We assume memcpy copies by words.
// TODO: expose and use move32.
byte* src_bytes = reinterpret_cast<byte*>(this);
byte* dst_bytes = reinterpret_cast<byte*>(copy.get());
size_t offset = sizeof(Object);
memcpy(dst_bytes + offset, src_bytes + offset, num_bytes - offset);
// Perform write barriers on copied object references.
if (c->IsArrayClass()) {
if (!c->GetComponentType()->IsPrimitive()) {
const ObjectArray<Object>* array = copy->AsObjectArray<Object>();
heap->WriteBarrierArray(copy.get(), 0, array->GetLength());
}
} else {
for (const Class* klass = c; klass != NULL; klass = klass->GetSuperClass()) {
size_t num_reference_fields = klass->NumReferenceInstanceFields();
for (size_t i = 0; i < num_reference_fields; ++i) {
ArtField* field = klass->GetInstanceField(i);
MemberOffset field_offset = field->GetOffset();
const Object* ref = copy->GetFieldObject<const Object*>(field_offset, false);
heap->WriteBarrierField(copy.get(), field_offset, ref);
}
}
}
if (c->IsFinalizable()) {
heap->AddFinalizerReference(Thread::Current(), copy.get());
}
return copy.get();
}
uint32_t Object::GenerateIdentityHashCode() {
static AtomicInteger seed(987654321 + std::time(nullptr));
uint32_t expected_value, new_value;
do {
expected_value = static_cast<uint32_t>(seed.load());
new_value = expected_value * 1103515245 + 12345;
} while (!seed.compare_and_swap(static_cast<int32_t>(expected_value),
static_cast<int32_t>(new_value)));
return expected_value & LockWord::kHashMask;
}
int32_t Object::IdentityHashCode() const {
while (true) {
LockWord lw = GetLockWord();
switch (lw.GetState()) {
case LockWord::kUnlocked: {
// Try to compare and swap in a new hash, if we succeed we will return the hash on the next
// loop iteration.
LockWord hash_word(LockWord::FromHashCode(GenerateIdentityHashCode()));
DCHECK_EQ(hash_word.GetState(), LockWord::kHashCode);
if (const_cast<Object*>(this)->CasLockWord(lw, hash_word)) {
return hash_word.GetHashCode();
}
break;
}
case LockWord::kThinLocked: {
// Inflate the thin lock to a monitor and stick the hash code inside of the monitor.
Thread* self = Thread::Current();
Monitor::InflateThinLocked(self, const_cast<Object*>(this), lw, GenerateIdentityHashCode());
break;
}
case LockWord::kFatLocked: {
// Already inflated, return the has stored in the monitor.
Monitor* monitor = lw.FatLockMonitor();
DCHECK(monitor != nullptr);
return monitor->GetHashCode();
}
case LockWord::kHashCode: {
return lw.GetHashCode();
}
}
}
LOG(FATAL) << "Unreachable";
return 0;
}
void Object::CheckFieldAssignmentImpl(MemberOffset field_offset, const Object* new_value) {
const Class* c = GetClass();
if (Runtime::Current()->GetClassLinker() == NULL ||
!Runtime::Current()->GetHeap()->IsObjectValidationEnabled() ||
!c->IsResolved()) {
return;
}
for (const Class* cur = c; cur != NULL; cur = cur->GetSuperClass()) {
ObjectArray<ArtField>* fields = cur->GetIFields();
if (fields != NULL) {
size_t num_ref_ifields = cur->NumReferenceInstanceFields();
for (size_t i = 0; i < num_ref_ifields; ++i) {
ArtField* field = fields->Get(i);
if (field->GetOffset().Int32Value() == field_offset.Int32Value()) {
FieldHelper fh(field);
CHECK(fh.GetType()->IsAssignableFrom(new_value->GetClass()));
return;
}
}
}
}
if (c->IsArrayClass()) {
// Bounds and assign-ability done in the array setter.
return;
}
if (IsClass()) {
ObjectArray<ArtField>* fields = AsClass()->GetSFields();
if (fields != NULL) {
size_t num_ref_sfields = AsClass()->NumReferenceStaticFields();
for (size_t i = 0; i < num_ref_sfields; ++i) {
ArtField* field = fields->Get(i);
if (field->GetOffset().Int32Value() == field_offset.Int32Value()) {
FieldHelper fh(field);
CHECK(fh.GetType()->IsAssignableFrom(new_value->GetClass()));
return;
}
}
}
}
LOG(FATAL) << "Failed to find field for assignment to " << reinterpret_cast<void*>(this)
<< " of type " << PrettyDescriptor(c) << " at offset " << field_offset;
}
} // namespace mirror
} // namespace art
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