ark_runtime_core/runtime/object_header.cpp

/*
 * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
 * 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 "runtime/include/object_header.h"

#include "runtime/include/coretypes/array.h"
#include "runtime/include/coretypes/class.h"
#include "runtime/include/runtime.h"
#include "runtime/include/thread.h"
#include "runtime/include/panda_vm.h"
#include "runtime/mem/vm_handle.h"
#include "runtime/monitor_pool.h"
#include "runtime/handle_base-inl.h"

namespace panda {

/* static */
ObjectHeader *ObjectHeader::CreateObject(panda::BaseClass *klass, bool non_movable)
{
#ifndef NDEBUG
    if (!klass->IsDynamicClass()) {
        auto cls = static_cast<panda::Class *>(klass);
        ASSERT(cls->IsInstantiable());
        ASSERT(!cls->IsArrayClass());
        ASSERT(!cls->IsStringClass());
    }
#endif

    size_t size = klass->GetObjectSize();
    ASSERT(size != 0);
    mem::HeapManager *heap_manager = Thread::GetCurrent()->GetVM()->GetHeapManager();
    ObjectHeader *obj {nullptr};
    if (LIKELY(!non_movable)) {
        obj = heap_manager->AllocateObject(klass, size);
    } else {
        obj = heap_manager->AllocateNonMovableObject(klass, size);
    }
    return obj;
}

/* static */
ObjectHeader *ObjectHeader::Create(BaseClass *klass)
{
    return CreateObject(klass, false);
}

/* static */
ObjectHeader *ObjectHeader::CreateNonMovable(BaseClass *klass)
{
    return CreateObject(klass, true);
}

bool ObjectHeader::AtomicSetMark(MarkWord old_mark_word, MarkWord new_mark_word)
{
    // This is the way to operate with casting MarkWordSize <-> MarkWord and atomics
    auto ptr = reinterpret_cast<MarkWord *>(&markWord_);
    auto atomic_ptr = reinterpret_cast<std::atomic<MarkWord> *>(ptr);
    return atomic_ptr->compare_exchange_weak(old_mark_word, new_mark_word);
}

uint32_t ObjectHeader::GetHashCodeFromMonitor(Monitor *monitor_p)
{
    if (monitor_p->GetHashCode() == 0) {
        Monitor::MonitorEnter(this);
        // We check it again in case someone changed it before we aquire monitor
        if (monitor_p->GetHashCode() == 0) {
            monitor_p->SetHashCode(GenerateHashCode());
        }
        Monitor::MonitorExit(this);
    }

    return monitor_p->GetHashCode();
}

uint32_t ObjectHeader::GetHashCode()
{
    while (true) {
        auto mark = this->AtomicGetMark();
        switch (mark.GetState()) {
            case MarkWord::STATE_UNLOCKED: {
                auto hash_mark = mark.DecodeFromHash(GenerateHashCode());
                ASSERT(hash_mark.GetState() == MarkWord::STATE_HASHED);
                this->AtomicSetMark(mark, hash_mark);
                break;
            }
            case MarkWord::STATE_LIGHT_LOCKED: {
                // Futexes and has support for locking with non-current thread.
                auto thread = MTManagedThread::GetCurrent();
                // Try to inflate and if it fails, wait a bit before trying again.
                if (!Monitor::Inflate(this, thread)) {
                    static constexpr uint64_t SLEEP_MS = 10;
                    MTManagedThread::Sleep(SLEEP_MS);
                }
                break;
            }
            case MarkWord::STATE_HEAVY_LOCKED: {
                auto monitor_id = mark.GetMonitorId();
                auto monitor_p = MonitorPool::LookupMonitor(Thread::GetCurrent()->GetVM(), monitor_id);
                if (monitor_p != nullptr) {
                    return GetHashCodeFromMonitor(monitor_p);
                }
                LOG(FATAL, RUNTIME) << "Error on GetHashCode(): no monitor on heavy locked state";
                break;
            }
            case MarkWord::STATE_HASHED: {
                return mark.GetHash();
            }
            default: {
                LOG(FATAL, RUNTIME) << "Error on GetHashCode(): invalid state";
            }
        }
    }
}

ObjectHeader *ObjectHeader::Clone(ObjectHeader *src)
{
    LOG_IF(src->ClassAddr<Class>()->GetManagedObject() == src, FATAL, RUNTIME) << "Can't clone a class";
    return ObjectHeader::ShallowCopy(src);
}

ObjectHeader *ObjectHeader::ShallowCopy(ObjectHeader *src)
{
    auto object_class = src->ClassAddr<Class>();
    std::size_t obj_size = src->ObjectSize();

    // AllocateObject can trigger gc, use handle for src.
    auto thread = ManagedThread::GetCurrent();
    mem::HeapManager *heap_manager = thread->GetVM()->GetHeapManager();
    [[maybe_unused]] HandleScope<ObjectHeader *> scope(thread);
    VMHandle<ObjectHeader> src_handle(thread, src);

    ObjectHeader *dst = nullptr;
    // Determine whether object is non-movable
    if (PoolManager::GetMmapMemPool()->GetSpaceTypeForAddr(src) == SpaceType::SPACE_TYPE_NON_MOVABLE_OBJECT) {
        dst = heap_manager->AllocateNonMovableObject(object_class, obj_size);
    } else {
        dst = heap_manager->AllocateObject(object_class, obj_size);
    }
    if (dst == nullptr) {
        return nullptr;
    }
    ASSERT(PoolManager::GetMmapMemPool()->GetSpaceTypeForAddr(src) ==
           PoolManager::GetMmapMemPool()->GetSpaceTypeForAddr(dst));

    Span<uint8_t> src_sp(reinterpret_cast<uint8_t *>(src_handle.GetPtr()), obj_size);
    Span<uint8_t> dst_sp(reinterpret_cast<uint8_t *>(dst), obj_size);
    constexpr const std::size_t WORD_SIZE = sizeof(uintptr_t);
    std::size_t bytes_to_copy = obj_size - ObjectHeader::ObjectHeaderSize();
    std::size_t words_to_copy = bytes_to_copy / WORD_SIZE;
    std::size_t remaining_offset = ObjectHeader::ObjectHeaderSize() + WORD_SIZE * words_to_copy;
    // copy words
    for (std::size_t i = static_cast<size_t>(ObjectHeader::ObjectHeaderSize()); i < remaining_offset; i += WORD_SIZE) {
        reinterpret_cast<std::atomic<uintptr_t> *>(&dst_sp[i])
            ->store(reinterpret_cast<std::atomic<uintptr_t> *>(&src_sp[i])->load(std::memory_order_relaxed),
                    std::memory_order_relaxed);
    }
    // copy remaining bytes
    for (std::size_t i = remaining_offset; i < obj_size; i++) {
        reinterpret_cast<std::atomic<uint8_t> *>(&dst_sp[i])
            ->store(reinterpret_cast<std::atomic<uint8_t> *>(&src_sp[i])->load(std::memory_order_relaxed),
                    std::memory_order_relaxed);
    }

    // Call barriers here.
    auto *barrier_set = thread->GetVM()->GetGC()->GetBarrierSet();
    // We don't need pre barrier here because we don't change any links inside main object
    // Post barrier
    auto gc_post_barrier_type = barrier_set->GetPostType();
    if (!mem::IsEmptyBarrier(gc_post_barrier_type)) {
        if (object_class->IsArrayClass()) {
            if (object_class->IsObjectArrayClass()) {
                barrier_set->PostBarrierArrayWrite(dst, obj_size);
            }
        } else {
            barrier_set->PostBarrierEveryObjectFieldWrite(dst, obj_size);
        }
    }
    return dst;
}

size_t ObjectHeader::ObjectSize() const
{
    auto *klass = ClassAddr<Class>();

    if (klass->IsArrayClass()) {
        return static_cast<const coretypes::Array *>(this)->ObjectSize();
    }

    if (klass->IsStringClass()) {
        return static_cast<const coretypes::String *>(this)->ObjectSize();
    }

    if (klass->IsClassClass()) {
        auto cls = panda::Class::FromClassObject(const_cast<ObjectHeader *>(this));
        if (cls != nullptr) {
            return panda::Class::GetClassObjectSizeFromClass(cls);
        }
    }

    return klass->GetObjectSize();
}

}  // namespace panda