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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_HEAP_HEAP_INL_H_
#define V8_HEAP_HEAP_INL_H_

#include <atomic>
#include <cmath>

// Clients of this interface shouldn't depend on lots of heap internals.
// Avoid including anything but `heap.h` from `src/heap` where possible.
#include "src/base/atomic-utils.h"
#include "src/base/atomicops.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/platform.h"
#include "src/common/assert-scope.h"
#include "src/common/code-memory-access-inl.h"
#include "src/execution/isolate-data.h"
#include "src/execution/isolate.h"
#include "src/heap/concurrent-allocator-inl.h"
#include "src/heap/concurrent-allocator.h"
#include "src/heap/heap-allocator-inl.h"
#include "src/heap/heap-write-barrier.h"
#include "src/heap/heap.h"
#include "src/heap/large-spaces.h"
#include "src/heap/marking-state-inl.h"
#include "src/heap/memory-allocator.h"
#include "src/heap/memory-chunk-layout.h"
#include "src/heap/memory-chunk.h"
#include "src/heap/new-spaces-inl.h"
#include "src/heap/paged-spaces-inl.h"
#include "src/heap/read-only-heap.h"
#include "src/heap/read-only-spaces.h"
#include "src/heap/safepoint.h"
#include "src/heap/spaces-inl.h"
#include "src/heap/third-party/heap-api.h"
#include "src/objects/allocation-site-inl.h"
#include "src/objects/cell-inl.h"
#include "src/objects/descriptor-array.h"
#include "src/objects/feedback-cell-inl.h"
#include "src/objects/feedback-vector.h"
#include "src/objects/objects-inl.h"
#include "src/objects/oddball.h"
#include "src/objects/property-cell.h"
#include "src/objects/scope-info.h"
#include "src/objects/slots-inl.h"
#include "src/objects/struct-inl.h"
#include "src/objects/visitors-inl.h"
#include "src/profiler/heap-profiler.h"
#include "src/roots/static-roots.h"
#include "src/strings/string-hasher.h"
#include "src/utils/ostreams.h"
#include "src/zone/zone-list-inl.h"

namespace v8 {
namespace internal {

template <typename T>
Tagged<T> ForwardingAddress(Tagged<T> heap_obj) {
  MapWord map_word = heap_obj->map_word(kRelaxedLoad);

  if (map_word.IsForwardingAddress()) {
    return Tagged<T>::cast(map_word.ToForwardingAddress(heap_obj));
  } else if (Heap::InFromPage(heap_obj)) {
    DCHECK(!v8_flags.minor_ms);
    return Tagged<T>();
  } else {
    return heap_obj;
  }
}

// static
base::EnumSet<CodeFlushMode> Heap::GetCodeFlushMode(Isolate* isolate) {
  if (isolate->disable_bytecode_flushing()) {
    return base::EnumSet<CodeFlushMode>();
  }

  base::EnumSet<CodeFlushMode> code_flush_mode;
  if (v8_flags.flush_bytecode) {
    code_flush_mode.Add(CodeFlushMode::kFlushBytecode);
  }

  if (v8_flags.flush_baseline_code) {
    code_flush_mode.Add(CodeFlushMode::kFlushBaselineCode);
  }

  if (v8_flags.stress_flush_code) {
    // This is to check tests accidentally don't miss out on adding either flush
    // bytecode or flush code along with stress flush code. stress_flush_code
    // doesn't do anything if either one of them isn't enabled.
    DCHECK(v8_flags.fuzzing || v8_flags.flush_baseline_code ||
           v8_flags.flush_bytecode);
    code_flush_mode.Add(CodeFlushMode::kStressFlushCode);
  }

  return code_flush_mode;
}

Isolate* Heap::isolate() const { return Isolate::FromHeap(this); }

bool Heap::IsMainThread() const {
  return isolate()->thread_id() == ThreadId::Current();
}

bool Heap::IsSharedMainThread() const {
  if (!isolate()->has_shared_space()) return false;
  Isolate* shared_space_isolate = isolate()->shared_space_isolate();
  return shared_space_isolate->thread_id() == ThreadId::Current();
}

int64_t Heap::external_memory() { return external_memory_.total(); }

int64_t Heap::update_external_memory(int64_t delta) {
  return external_memory_.Update(delta);
}

RootsTable& Heap::roots_table() { return isolate()->roots_table(); }

#define ROOT_ACCESSOR(Type, name, CamelName)                     \
  Tagged<Type> Heap::name() {                                    \
    return Tagged<Type>::cast(                                   \
        Tagged<Object>(roots_table()[RootIndex::k##CamelName])); \
  }
MUTABLE_ROOT_LIST(ROOT_ACCESSOR)
#undef ROOT_ACCESSOR

Tagged<FixedArray> Heap::single_character_string_table() {
  return Tagged<FixedArray>::cast(
      Tagged<Object>(roots_table()[RootIndex::kSingleCharacterStringTable]));
}

#define STATIC_ROOTS_FAILED_MSG                                            \
  "Read-only heap layout changed. Run `tools/dev/gen-static-roots.py` to " \
  "update static-roots.h."
#if V8_STATIC_ROOTS_BOOL
// Check all read only roots are allocated where we expect it. Skip `Exception`
// which changes during setup-heap-internal.
#define DCHECK_STATIC_ROOT(obj, name)                                        \
  if constexpr (RootsTable::IsReadOnly(RootIndex::k##name) &&                \
                RootIndex::k##name != RootIndex::kException) {               \
    DCHECK_WITH_MSG(V8HeapCompressionScheme::CompressObject(obj.ptr()) ==    \
                        StaticReadOnlyRootsPointerTable[static_cast<size_t>( \
                            RootIndex::k##name)],                            \
                    STATIC_ROOTS_FAILED_MSG);                                \
  }
#else
#define DCHECK_STATIC_ROOT(obj, name)
#endif

#define ROOT_ACCESSOR(type, name, CamelName)                                   \
  void Heap::set_##name(Tagged<type> value) {                                  \
    /* The deserializer makes use of the fact that these common roots are */   \
    /* never in new space and never on a page that is being compacted.    */   \
    DCHECK_IMPLIES(deserialization_complete(),                                 \
                   !RootsTable::IsImmortalImmovable(RootIndex::k##CamelName)); \
    if constexpr (RootsTable::IsImmortalImmovable(RootIndex::k##CamelName)) {  \
      /* Cast via object to avoid compile errors when trying to cast a Smi */  \
      /* to HeapObject (these Smis will anyway be excluded by */               \
      /* RootsTable::IsImmortalImmovable but this isn't enough for the*/       \
      /* compiler, even with `if constexpr`)*/                                 \
      DCHECK(                                                                  \
          IsImmovable(Tagged<HeapObject>::cast(Tagged<Object>::cast(value)))); \
    }                                                                          \
    DCHECK_STATIC_ROOT(value, CamelName);                                      \
    roots_table()[RootIndex::k##CamelName] = value.ptr();                      \
  }
ROOT_LIST(ROOT_ACCESSOR)
#undef ROOT_ACCESSOR
#undef CHECK_STATIC_ROOT
#undef STATIC_ROOTS_FAILED_MSG

void Heap::SetRootMaterializedObjects(Tagged<FixedArray> objects) {
  roots_table()[RootIndex::kMaterializedObjects] = objects.ptr();
}

void Heap::SetRootScriptList(Tagged<Object> value) {
  roots_table()[RootIndex::kScriptList] = value.ptr();
}

void Heap::SetMessageListeners(Tagged<ArrayList> value) {
  roots_table()[RootIndex::kMessageListeners] = value.ptr();
}

void Heap::SetFunctionsMarkedForManualOptimization(Tagged<Object> hash_table) {
  DCHECK(IsObjectHashTable(hash_table) || IsUndefined(hash_table, isolate()));
  roots_table()[RootIndex::kFunctionsMarkedForManualOptimization] =
      hash_table.ptr();
}

PagedSpace* Heap::paged_space(int idx) const {
  DCHECK(idx == OLD_SPACE || idx == CODE_SPACE || idx == SHARED_SPACE ||
         idx == TRUSTED_SPACE);
  return static_cast<PagedSpace*>(space_[idx].get());
}

Space* Heap::space(int idx) const { return space_[idx].get(); }

Address* Heap::NewSpaceAllocationTopAddress() {
  return new_space_
             ? isolate()->isolate_data()->new_allocation_info_.top_address()
             : nullptr;
}

Address* Heap::NewSpaceAllocationLimitAddress() {
  return new_space_
             ? isolate()->isolate_data()->new_allocation_info_.limit_address()
             : nullptr;
}

Address* Heap::OldSpaceAllocationTopAddress() {
  return allocator()->old_space_allocator()->allocation_top_address();
}

Address* Heap::OldSpaceAllocationLimitAddress() {
  return allocator()->old_space_allocator()->allocation_limit_address();
}

inline const base::AddressRegion& Heap::code_region() {
#ifdef V8_ENABLE_THIRD_PARTY_HEAP
  return tp_heap_->GetCodeRange();
#else
  static constexpr base::AddressRegion kEmptyRegion;
  return code_range_ ? code_range_->reservation()->region() : kEmptyRegion;
#endif
}

Address Heap::code_range_base() {
  return code_range_ ? code_range_->base() : kNullAddress;
}

int Heap::MaxRegularHeapObjectSize(AllocationType allocation) {
  if (!V8_ENABLE_THIRD_PARTY_HEAP_BOOL &&
      (allocation == AllocationType::kCode)) {
    DCHECK_EQ(MemoryChunkLayout::MaxRegularCodeObjectSize(),
              max_regular_code_object_size_);
    return max_regular_code_object_size_;
  }
  return kMaxRegularHeapObjectSize;
}

AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationType type,
                                   AllocationOrigin origin,
                                   AllocationAlignment alignment) {
  return heap_allocator_.AllocateRaw(size_in_bytes, type, origin, alignment);
}

Address Heap::AllocateRawOrFail(int size, AllocationType allocation,
                                AllocationOrigin origin,
                                AllocationAlignment alignment) {
  return heap_allocator_
      .AllocateRawWith<HeapAllocator::kRetryOrFail>(size, allocation, origin,
                                                    alignment)
      .address();
}

void Heap::RegisterExternalString(Tagged<String> string) {
  DCHECK(IsExternalString(string));
  DCHECK(!IsThinString(string));
  external_string_table_.AddString(string);
}

void Heap::FinalizeExternalString(Tagged<String> string) {
  DCHECK(IsExternalString(string));
  Tagged<ExternalString> ext_string = Tagged<ExternalString>::cast(string);

  if (!v8_flags.enable_third_party_heap) {
    Page* page = Page::FromHeapObject(string);
    page->DecrementExternalBackingStoreBytes(
        ExternalBackingStoreType::kExternalString,
        ext_string->ExternalPayloadSize());
  }

  ext_string->DisposeResource(isolate());
}

Address Heap::NewSpaceTop() {
  return new_space_ ? allocator()->new_space_allocator()->top() : kNullAddress;
}

Address Heap::NewSpaceLimit() {
  return new_space_ ? allocator()->new_space_allocator()->top() : kNullAddress;
}

bool Heap::InYoungGeneration(Tagged<Object> object) {
  DCHECK(!HasWeakHeapObjectTag(object));
  return IsHeapObject(object) && InYoungGeneration(HeapObject::cast(object));
}

// static
bool Heap::InYoungGeneration(MaybeObject object) {
  Tagged<HeapObject> heap_object;
  return object.GetHeapObject(&heap_object) && InYoungGeneration(heap_object);
}

// static
bool Heap::InYoungGeneration(Tagged<HeapObject> heap_object) {
  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) return false;
  bool result =
      BasicMemoryChunk::FromHeapObject(heap_object)->InYoungGeneration();
#ifdef DEBUG
  // If in the young generation, then check we're either not in the middle of
  // GC or the object is in to-space.
  if (result) {
    // If the object is in the young generation, then it's not in RO_SPACE so
    // this is safe.
    Heap* heap = Heap::FromWritableHeapObject(heap_object);
    DCHECK_IMPLIES(heap->gc_state() == NOT_IN_GC, InToPage(heap_object));
  }
#endif
  return result;
}

// static
bool Heap::InWritableSharedSpace(MaybeObject object) {
  Tagged<HeapObject> heap_object;
  return object.GetHeapObject(&heap_object) &&
         heap_object.InWritableSharedSpace();
}

// static
bool Heap::InFromPage(Tagged<Object> object) {
  DCHECK(!HasWeakHeapObjectTag(object));
  return IsHeapObject(object) && InFromPage(HeapObject::cast(object));
}

// static
bool Heap::InFromPage(MaybeObject object) {
  Tagged<HeapObject> heap_object;
  return object.GetHeapObject(&heap_object) && InFromPage(heap_object);
}

// static
bool Heap::InFromPage(Tagged<HeapObject> heap_object) {
  return BasicMemoryChunk::FromHeapObject(heap_object)->IsFromPage();
}

// static
bool Heap::InToPage(Tagged<Object> object) {
  DCHECK(!HasWeakHeapObjectTag(object));
  return IsHeapObject(object) && InToPage(HeapObject::cast(object));
}

// static
bool Heap::InToPage(MaybeObject object) {
  Tagged<HeapObject> heap_object;
  return object.GetHeapObject(&heap_object) && InToPage(heap_object);
}

// static
bool Heap::InToPage(Tagged<HeapObject> heap_object) {
  return BasicMemoryChunk::FromHeapObject(heap_object)->IsToPage();
}

bool Heap::InOldSpace(Tagged<Object> object) {
  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) {
    return object.IsHeapObject() &&
           third_party_heap::Heap::InOldSpace(object.ptr());
  }
  return old_space_->Contains(object);
}

// static
Heap* Heap::FromWritableHeapObject(Tagged<HeapObject> obj) {
  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) {
    return Heap::GetIsolateFromWritableObject(obj)->heap();
  }
  BasicMemoryChunk* chunk = BasicMemoryChunk::FromHeapObject(obj);
  // RO_SPACE can be shared between heaps, so we can't use RO_SPACE objects to
  // find a heap. The exception is when the ReadOnlySpace is writeable, during
  // bootstrapping, so explicitly allow this case.
  SLOW_DCHECK(chunk->IsWritable());
  Heap* heap = chunk->heap();
  SLOW_DCHECK(heap != nullptr);
  return heap;
}

void Heap::CopyBlock(Address dst, Address src, int byte_size) {
  DCHECK(IsAligned(byte_size, kTaggedSize));
  CopyTagged(dst, src, static_cast<size_t>(byte_size / kTaggedSize));
}

bool Heap::IsPendingAllocationInternal(Tagged<HeapObject> object) {
  DCHECK(deserialization_complete());

  if (V8_ENABLE_THIRD_PARTY_HEAP_BOOL) {
    return tp_heap_->IsPendingAllocation(object);
  }

  BasicMemoryChunk* chunk = BasicMemoryChunk::FromHeapObject(object);
  if (chunk->InReadOnlySpace()) return false;

  BaseSpace* base_space = chunk->owner();
  Address addr = object.address();

  switch (base_space->identity()) {
    case NEW_SPACE: {
      return new_space_->main_allocator()->IsPendingAllocation(addr);
    }

    case OLD_SPACE:
    case CODE_SPACE:
    case TRUSTED_SPACE: {
      PagedSpace* paged_space = static_cast<PagedSpace*>(base_space);
      return paged_space->main_allocator()->IsPendingAllocation(addr);
    }

    case LO_SPACE:
    case CODE_LO_SPACE:
    case TRUSTED_LO_SPACE:
    case NEW_LO_SPACE: {
      LargeObjectSpace* large_space =
          static_cast<LargeObjectSpace*>(base_space);
      base::SharedMutexGuard<base::kShared> guard(
          large_space->pending_allocation_mutex());
      return addr == large_space->pending_object();
    }

    case SHARED_SPACE:
    case SHARED_LO_SPACE:
      // TODO(v8:13267): Ensure that all shared space objects have a memory
      // barrier after initialization.
      return false;

    case RO_SPACE:
      UNREACHABLE();
  }

  UNREACHABLE();
}

bool Heap::IsPendingAllocation(Tagged<HeapObject> object) {
  bool result = IsPendingAllocationInternal(object);
  if (v8_flags.trace_pending_allocations && result) {
    StdoutStream{} << "Pending allocation: " << std::hex << "0x" << object.ptr()
                   << "\n";
  }
  return result;
}

bool Heap::IsPendingAllocation(Tagged<Object> object) {
  return IsHeapObject(object) && IsPendingAllocation(HeapObject::cast(object));
}

void Heap::ExternalStringTable::AddString(Tagged<String> string) {
  base::Optional<base::MutexGuard> guard;

  // With --shared-string-table client isolates may insert into the main
  // isolate's table concurrently.
  if (v8_flags.shared_string_table &&
      heap_->isolate()->is_shared_space_isolate()) {
    guard.emplace(&mutex_);
  }

  DCHECK(IsExternalString(string));
  DCHECK(!Contains(string));

  if (InYoungGeneration(string)) {
    young_strings_.push_back(string);
  } else {
    old_strings_.push_back(string);
  }
}

Tagged<Boolean> Heap::ToBoolean(bool condition) {
  ReadOnlyRoots roots(this);
  return roots.boolean_value(condition);
}

int Heap::NextScriptId() {
  FullObjectSlot last_script_id_slot(&roots_table()[RootIndex::kLastScriptId]);
  Tagged<Smi> last_id = Smi::cast(last_script_id_slot.Relaxed_Load());
  Tagged<Smi> new_id, last_id_before_cas;
  do {
    if (last_id.value() == Smi::kMaxValue) {
      static_assert(v8::UnboundScript::kNoScriptId == 0);
      new_id = Smi::FromInt(1);
    } else {
      new_id = Smi::FromInt(last_id.value() + 1);
    }

    // CAS returns the old value on success, and the current value in the slot
    // on failure. Therefore, we want to break if the returned value matches the
    // old value (last_id), and keep looping (with the new last_id value) if it
    // doesn't.
    last_id_before_cas = last_id;
    last_id =
        Smi::cast(last_script_id_slot.Relaxed_CompareAndSwap(last_id, new_id));
  } while (last_id != last_id_before_cas);

  return new_id.value();
}

int Heap::NextDebuggingId() {
  int last_id = last_debugging_id().value();
  if (last_id == DebugInfo::DebuggingIdBits::kMax) {
    last_id = DebugInfo::kNoDebuggingId;
  }
  last_id++;
  set_last_debugging_id(Smi::FromInt(last_id));
  return last_id;
}

int Heap::GetNextTemplateSerialNumber() {
  int next_serial_number = next_template_serial_number().value();
  set_next_template_serial_number(Smi::FromInt(next_serial_number + 1));
  return next_serial_number;
}

int Heap::MaxNumberToStringCacheSize() const {
  // Compute the size of the number string cache based on the max newspace size.
  // The number string cache has a minimum size based on twice the initial cache
  // size to ensure that it is bigger after being made 'full size'.
  size_t number_string_cache_size = max_semi_space_size_ / 512;
  number_string_cache_size =
      std::max(static_cast<size_t>(kInitialNumberStringCacheSize * 2),
               std::min(static_cast<size_t>(0x4000), number_string_cache_size));
  // There is a string and a number per entry so the length is twice the number
  // of entries.
  return static_cast<int>(number_string_cache_size * 2);
}

void Heap::IncrementExternalBackingStoreBytes(ExternalBackingStoreType type,
                                              size_t amount) {
  base::CheckedIncrement(&backing_store_bytes_, static_cast<uint64_t>(amount),
                         std::memory_order_relaxed);
  // TODO(mlippautz): Implement interrupt for global memory allocations that can
  // trigger garbage collections.
}

void Heap::DecrementExternalBackingStoreBytes(ExternalBackingStoreType type,
                                              size_t amount) {
  base::CheckedDecrement(&backing_store_bytes_, static_cast<uint64_t>(amount),
                         std::memory_order_relaxed);
}

bool Heap::HasDirtyJSFinalizationRegistries() {
  return !IsUndefined(dirty_js_finalization_registries_list(), isolate());
}

AlwaysAllocateScope::AlwaysAllocateScope(Heap* heap) : heap_(heap) {
  heap_->always_allocate_scope_count_++;
}

AlwaysAllocateScope::~AlwaysAllocateScope() {
  heap_->always_allocate_scope_count_--;
}

AlwaysAllocateScopeForTesting::AlwaysAllocateScopeForTesting(Heap* heap)
    : scope_(heap) {}

PagedNewSpace* Heap::paged_new_space() const {
  return PagedNewSpace::From(new_space());
}

#ifdef V8_ENABLE_THIRD_PARTY_HEAP
CodePageMemoryModificationScope::CodePageMemoryModificationScope(
    InstructionStream code)
    :
#if V8_HEAP_USE_PTHREAD_JIT_WRITE_PROTECT || V8_HEAP_USE_PKU_JIT_WRITE_PROTECT
      rwx_write_scope_("A part of CodePageMemoryModificationScope"),
#endif
      chunk_(nullptr),
      scope_active_(false) {
}
#else
CodePageMemoryModificationScope::CodePageMemoryModificationScope(
    Tagged<InstructionStream> code)
    : CodePageMemoryModificationScope(BasicMemoryChunk::FromHeapObject(code)) {}
#endif

#if V8_HEAP_USE_PTHREAD_JIT_WRITE_PROTECT || V8_HEAP_USE_PKU_JIT_WRITE_PROTECT
CodePageMemoryModificationScope::CodePageMemoryModificationScope(
    BasicMemoryChunk* chunk) {
  if (chunk->IsFlagSet(BasicMemoryChunk::IS_EXECUTABLE)) {
    rwx_write_scope_.emplace("A part of CodePageMemoryModificationScope");
  }
}
#else
CodePageMemoryModificationScope::CodePageMemoryModificationScope(
    BasicMemoryChunk* chunk)
    : chunk_(chunk),
      scope_active_(chunk_->IsFlagSet(BasicMemoryChunk::IS_EXECUTABLE) &&
                    chunk_->heap()->write_protect_code_memory()) {
  if (scope_active_) {
    DCHECK(IsAnyCodeSpace(chunk_->owner()->identity()));
    guard_.emplace(MemoryChunk::cast(chunk_)->SetCodeModificationPermissions());
  }
}
#endif

CodePageMemoryModificationScope::~CodePageMemoryModificationScope() {
#if !V8_HEAP_USE_PTHREAD_JIT_WRITE_PROTECT && !V8_HEAP_USE_PKU_JIT_WRITE_PROTECT
  if (scope_active_) {
    MemoryChunk::cast(chunk_)->SetDefaultCodePermissions();
  }
#endif
}

IgnoreLocalGCRequests::IgnoreLocalGCRequests(Heap* heap) : heap_(heap) {
  heap_->ignore_local_gc_requests_depth_++;
}

IgnoreLocalGCRequests::~IgnoreLocalGCRequests() {
  DCHECK_GT(heap_->ignore_local_gc_requests_depth_, 0);
  heap_->ignore_local_gc_requests_depth_--;
}

}  // namespace internal
}  // namespace v8

#endif  // V8_HEAP_HEAP_INL_H_

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