// 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 <cmath> // Clients of this interface shouldn't depend on lots of heap internals. // Do not include anything from src/heap other than src/heap/heap.h and its // write barrier here! #include "src/heap/heap-write-barrier.h" #include "src/heap/heap.h" #include "src/base/atomic-utils.h" #include "src/base/platform/platform.h" #include "src/feedback-vector.h" // TODO(mstarzinger): There is one more include to remove in order to no longer // leak heap internals to users of this interface! #include "src/heap/spaces-inl.h" #include "src/isolate-data.h" #include "src/isolate.h" #include "src/msan.h" #include "src/objects-inl.h" #include "src/objects/allocation-site-inl.h" #include "src/objects/api-callbacks-inl.h" #include "src/objects/cell-inl.h" #include "src/objects/descriptor-array.h" #include "src/objects/feedback-cell-inl.h" #include "src/objects/literal-objects-inl.h" #include "src/objects/oddball.h" #include "src/objects/property-cell.h" #include "src/objects/scope-info.h" #include "src/objects/script-inl.h" #include "src/objects/slots-inl.h" #include "src/objects/struct-inl.h" #include "src/profiler/heap-profiler.h" #include "src/string-hasher.h" #include "src/zone/zone-list-inl.h" namespace v8 { namespace internal { AllocationSpace AllocationResult::RetrySpace() { DCHECK(IsRetry()); return static_cast<AllocationSpace>(Smi::ToInt(object_)); } HeapObject AllocationResult::ToObjectChecked() { CHECK(!IsRetry()); return HeapObject::cast(object_); } Isolate* Heap::isolate() { return reinterpret_cast<Isolate*>( reinterpret_cast<intptr_t>(this) - reinterpret_cast<size_t>(reinterpret_cast<Isolate*>(16)->heap()) + 16); } int64_t Heap::external_memory() { return isolate()->isolate_data()->external_memory_; } void Heap::update_external_memory(int64_t delta) { isolate()->isolate_data()->external_memory_ += delta; } void Heap::update_external_memory_concurrently_freed(intptr_t freed) { external_memory_concurrently_freed_ += freed; } void Heap::account_external_memory_concurrently_freed() { isolate()->isolate_data()->external_memory_ -= external_memory_concurrently_freed_; external_memory_concurrently_freed_ = 0; } RootsTable& Heap::roots_table() { return isolate()->roots_table(); } #define ROOT_ACCESSOR(Type, name, CamelName) \ Type Heap::name() { \ return Type::cast(Object(roots_table()[RootIndex::k##CamelName])); \ } MUTABLE_ROOT_LIST(ROOT_ACCESSOR) #undef ROOT_ACCESSOR #define ROOT_ACCESSOR(type, name, CamelName) \ void Heap::set_##name(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)); \ DCHECK_IMPLIES(RootsTable::IsImmortalImmovable(RootIndex::k##CamelName), \ IsImmovable(HeapObject::cast(value))); \ roots_table()[RootIndex::k##CamelName] = value->ptr(); \ } ROOT_LIST(ROOT_ACCESSOR) #undef ROOT_ACCESSOR void Heap::SetRootMaterializedObjects(FixedArray objects) { roots_table()[RootIndex::kMaterializedObjects] = objects->ptr(); } void Heap::SetRootScriptList(Object value) { roots_table()[RootIndex::kScriptList] = value->ptr(); } void Heap::SetRootStringTable(StringTable value) { roots_table()[RootIndex::kStringTable] = value->ptr(); } void Heap::SetRootNoScriptSharedFunctionInfos(Object value) { roots_table()[RootIndex::kNoScriptSharedFunctionInfos] = value->ptr(); } void Heap::SetMessageListeners(TemplateList value) { roots_table()[RootIndex::kMessageListeners] = value->ptr(); } void Heap::SetPendingOptimizeForTestBytecode(Object hash_table) { DCHECK(hash_table->IsObjectHashTable() || hash_table->IsUndefined(isolate())); roots_table()[RootIndex::kPendingOptimizeForTestBytecode] = hash_table->ptr(); } PagedSpace* Heap::paged_space(int idx) { DCHECK_NE(idx, LO_SPACE); DCHECK_NE(idx, NEW_SPACE); DCHECK_NE(idx, CODE_LO_SPACE); DCHECK_NE(idx, NEW_LO_SPACE); return static_cast<PagedSpace*>(space_[idx]); } Space* Heap::space(int idx) { return space_[idx]; } Address* Heap::NewSpaceAllocationTopAddress() { return new_space_->allocation_top_address(); } Address* Heap::NewSpaceAllocationLimitAddress() { return new_space_->allocation_limit_address(); } Address* Heap::OldSpaceAllocationTopAddress() { return old_space_->allocation_top_address(); } Address* Heap::OldSpaceAllocationLimitAddress() { return old_space_->allocation_limit_address(); } void Heap::UpdateNewSpaceAllocationCounter() { new_space_allocation_counter_ = NewSpaceAllocationCounter(); } size_t Heap::NewSpaceAllocationCounter() { return new_space_allocation_counter_ + new_space()->AllocatedSinceLastGC(); } AllocationResult Heap::AllocateRaw(int size_in_bytes, AllocationType type, AllocationAlignment alignment) { DCHECK(AllowHandleAllocation::IsAllowed()); DCHECK(AllowHeapAllocation::IsAllowed()); DCHECK(gc_state_ == NOT_IN_GC); #ifdef V8_ENABLE_ALLOCATION_TIMEOUT if (FLAG_random_gc_interval > 0 || FLAG_gc_interval >= 0) { if (!always_allocate() && Heap::allocation_timeout_-- <= 0) { return AllocationResult::Retry(); } } #endif #ifdef DEBUG IncrementObjectCounters(); #endif bool large_object = size_in_bytes > kMaxRegularHeapObjectSize; HeapObject object; AllocationResult allocation; if (AllocationType::kYoung == type) { if (large_object) { if (FLAG_young_generation_large_objects) { allocation = new_lo_space_->AllocateRaw(size_in_bytes); } else { // If young generation large objects are disalbed we have to tenure the // allocation and violate the given allocation type. This could be // dangerous. We may want to remove FLAG_young_generation_large_objects // and avoid patching. allocation = lo_space_->AllocateRaw(size_in_bytes); } } else { allocation = new_space_->AllocateRaw(size_in_bytes, alignment); } } else if (AllocationType::kOld == type) { if (large_object) { allocation = lo_space_->AllocateRaw(size_in_bytes); } else { allocation = old_space_->AllocateRaw(size_in_bytes, alignment); } } else if (AllocationType::kCode == type) { if (size_in_bytes <= code_space()->AreaSize() && !large_object) { allocation = code_space_->AllocateRawUnaligned(size_in_bytes); } else { allocation = code_lo_space_->AllocateRaw(size_in_bytes); } } else if (AllocationType::kMap == type) { allocation = map_space_->AllocateRawUnaligned(size_in_bytes); } else if (AllocationType::kReadOnly == type) { #ifdef V8_USE_SNAPSHOT DCHECK(isolate_->serializer_enabled()); #endif DCHECK(!large_object); DCHECK(CanAllocateInReadOnlySpace()); allocation = read_only_space_->AllocateRaw(size_in_bytes, alignment); } else { UNREACHABLE(); } if (allocation.To(&object)) { if (AllocationType::kCode == type) { // Unprotect the memory chunk of the object if it was not unprotected // already. UnprotectAndRegisterMemoryChunk(object); ZapCodeObject(object->address(), size_in_bytes); } OnAllocationEvent(object, size_in_bytes); } return allocation; } void Heap::OnAllocationEvent(HeapObject object, int size_in_bytes) { for (auto& tracker : allocation_trackers_) { tracker->AllocationEvent(object->address(), size_in_bytes); } if (FLAG_verify_predictable) { ++allocations_count_; // Advance synthetic time by making a time request. MonotonicallyIncreasingTimeInMs(); UpdateAllocationsHash(object); UpdateAllocationsHash(size_in_bytes); if (allocations_count_ % FLAG_dump_allocations_digest_at_alloc == 0) { PrintAllocationsHash(); } } else if (FLAG_fuzzer_gc_analysis) { ++allocations_count_; } else if (FLAG_trace_allocation_stack_interval > 0) { ++allocations_count_; if (allocations_count_ % FLAG_trace_allocation_stack_interval == 0) { isolate()->PrintStack(stdout, Isolate::kPrintStackConcise); } } } bool Heap::CanAllocateInReadOnlySpace() { return !deserialization_complete_ && (isolate()->serializer_enabled() || !isolate()->initialized_from_snapshot()); } void Heap::UpdateAllocationsHash(HeapObject object) { Address object_address = object->address(); MemoryChunk* memory_chunk = MemoryChunk::FromAddress(object_address); AllocationSpace allocation_space = memory_chunk->owner()->identity(); STATIC_ASSERT(kSpaceTagSize + kPageSizeBits <= 32); uint32_t value = static_cast<uint32_t>(object_address - memory_chunk->address()) | (static_cast<uint32_t>(allocation_space) << kPageSizeBits); UpdateAllocationsHash(value); } void Heap::UpdateAllocationsHash(uint32_t value) { uint16_t c1 = static_cast<uint16_t>(value); uint16_t c2 = static_cast<uint16_t>(value >> 16); raw_allocations_hash_ = StringHasher::AddCharacterCore(raw_allocations_hash_, c1); raw_allocations_hash_ = StringHasher::AddCharacterCore(raw_allocations_hash_, c2); } void Heap::RegisterExternalString(String string) { DCHECK(string->IsExternalString()); DCHECK(!string->IsThinString()); external_string_table_.AddString(string); } void Heap::FinalizeExternalString(String string) { DCHECK(string->IsExternalString()); Page* page = Page::FromHeapObject(string); ExternalString ext_string = ExternalString::cast(string); page->DecrementExternalBackingStoreBytes( ExternalBackingStoreType::kExternalString, ext_string->ExternalPayloadSize()); ext_string->DisposeResource(); } Address Heap::NewSpaceTop() { return new_space_->top(); } bool Heap::InYoungGeneration(Object object) { DCHECK(!HasWeakHeapObjectTag(object)); return object->IsHeapObject() && InYoungGeneration(HeapObject::cast(object)); } // static bool Heap::InYoungGeneration(MaybeObject object) { HeapObject heap_object; return object->GetHeapObject(&heap_object) && InYoungGeneration(heap_object); } // static bool Heap::InYoungGeneration(HeapObject heap_object) { bool result = MemoryChunk::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::InFromPage(Object object) { DCHECK(!HasWeakHeapObjectTag(object)); return object->IsHeapObject() && InFromPage(HeapObject::cast(object)); } // static bool Heap::InFromPage(MaybeObject object) { HeapObject heap_object; return object->GetHeapObject(&heap_object) && InFromPage(heap_object); } // static bool Heap::InFromPage(HeapObject heap_object) { return MemoryChunk::FromHeapObject(heap_object)->IsFromPage(); } // static bool Heap::InToPage(Object object) { DCHECK(!HasWeakHeapObjectTag(object)); return object->IsHeapObject() && InToPage(HeapObject::cast(object)); } // static bool Heap::InToPage(MaybeObject object) { HeapObject heap_object; return object->GetHeapObject(&heap_object) && InToPage(heap_object); } // static bool Heap::InToPage(HeapObject heap_object) { return MemoryChunk::FromHeapObject(heap_object)->IsToPage(); } bool Heap::InOldSpace(Object object) { return old_space_->Contains(object); } // static Heap* Heap::FromWritableHeapObject(const HeapObject obj) { MemoryChunk* chunk = MemoryChunk::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->owner()->identity() != RO_SPACE || static_cast<ReadOnlySpace*>(chunk->owner())->writable()); Heap* heap = chunk->heap(); SLOW_DCHECK(heap != nullptr); return heap; } bool Heap::ShouldBePromoted(Address old_address) { Page* page = Page::FromAddress(old_address); Address age_mark = new_space_->age_mark(); return page->IsFlagSet(MemoryChunk::NEW_SPACE_BELOW_AGE_MARK) && (!page->ContainsLimit(age_mark) || old_address < age_mark); } 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)); } template <Heap::FindMementoMode mode> AllocationMemento Heap::FindAllocationMemento(Map map, HeapObject object) { Address object_address = object->address(); Address memento_address = object_address + object->SizeFromMap(map); Address last_memento_word_address = memento_address + kTaggedSize; // If the memento would be on another page, bail out immediately. if (!Page::OnSamePage(object_address, last_memento_word_address)) { return AllocationMemento(); } HeapObject candidate = HeapObject::FromAddress(memento_address); MapWordSlot candidate_map_slot = candidate->map_slot(); // This fast check may peek at an uninitialized word. However, the slow check // below (memento_address == top) ensures that this is safe. Mark the word as // initialized to silence MemorySanitizer warnings. MSAN_MEMORY_IS_INITIALIZED(candidate_map_slot.address(), kTaggedSize); if (!candidate_map_slot.contains_value( ReadOnlyRoots(this).allocation_memento_map().ptr())) { return AllocationMemento(); } // Bail out if the memento is below the age mark, which can happen when // mementos survived because a page got moved within new space. Page* object_page = Page::FromAddress(object_address); if (object_page->IsFlagSet(Page::NEW_SPACE_BELOW_AGE_MARK)) { Address age_mark = reinterpret_cast<SemiSpace*>(object_page->owner())->age_mark(); if (!object_page->Contains(age_mark)) { return AllocationMemento(); } // Do an exact check in the case where the age mark is on the same page. if (object_address < age_mark) { return AllocationMemento(); } } AllocationMemento memento_candidate = AllocationMemento::cast(candidate); // Depending on what the memento is used for, we might need to perform // additional checks. Address top; switch (mode) { case Heap::kForGC: return memento_candidate; case Heap::kForRuntime: if (memento_candidate.is_null()) return AllocationMemento(); // Either the object is the last object in the new space, or there is // another object of at least word size (the header map word) following // it, so suffices to compare ptr and top here. top = NewSpaceTop(); DCHECK(memento_address == top || memento_address + HeapObject::kHeaderSize <= top || !Page::OnSamePage(memento_address, top - 1)); if ((memento_address != top) && memento_candidate->IsValid()) { return memento_candidate; } return AllocationMemento(); default: UNREACHABLE(); } UNREACHABLE(); } void Heap::UpdateAllocationSite(Map map, HeapObject object, PretenuringFeedbackMap* pretenuring_feedback) { DCHECK_NE(pretenuring_feedback, &global_pretenuring_feedback_); #ifdef DEBUG MemoryChunk* chunk = MemoryChunk::FromHeapObject(object); DCHECK_IMPLIES(chunk->IsToPage(), chunk->IsFlagSet(MemoryChunk::PAGE_NEW_NEW_PROMOTION)); DCHECK_IMPLIES(!chunk->InYoungGeneration(), chunk->IsFlagSet(MemoryChunk::PAGE_NEW_OLD_PROMOTION)); #endif if (!FLAG_allocation_site_pretenuring || !AllocationSite::CanTrack(map->instance_type())) { return; } AllocationMemento memento_candidate = FindAllocationMemento<kForGC>(map, object); if (memento_candidate.is_null()) return; // Entering cached feedback is used in the parallel case. We are not allowed // to dereference the allocation site and rather have to postpone all checks // till actually merging the data. Address key = memento_candidate->GetAllocationSiteUnchecked(); (*pretenuring_feedback)[AllocationSite::unchecked_cast(Object(key))]++; } void Heap::ExternalStringTable::AddString(String string) { DCHECK(string->IsExternalString()); DCHECK(!Contains(string)); if (InYoungGeneration(string)) { young_strings_.push_back(string); } else { old_strings_.push_back(string); } } Oddball Heap::ToBoolean(bool condition) { ReadOnlyRoots roots(this); return condition ? roots.true_value() : roots.false_value(); } int Heap::NextScriptId() { int last_id = last_script_id()->value(); if (last_id == Smi::kMaxValue) last_id = v8::UnboundScript::kNoScriptId; last_id++; set_last_script_id(Smi::FromInt(last_id)); return last_id; } 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() + 1; set_next_template_serial_number(Smi::FromInt(next_serial_number)); 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 = Max(static_cast<size_t>(kInitialNumberStringCacheSize * 2), Min<size_t>(0x4000u, 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_, amount); // 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_, amount); } AlwaysAllocateScope::AlwaysAllocateScope(Heap* heap) : heap_(heap) { heap_->always_allocate_scope_count_++; } AlwaysAllocateScope::AlwaysAllocateScope(Isolate* isolate) : AlwaysAllocateScope(isolate->heap()) {} AlwaysAllocateScope::~AlwaysAllocateScope() { heap_->always_allocate_scope_count_--; } CodeSpaceMemoryModificationScope::CodeSpaceMemoryModificationScope(Heap* heap) : heap_(heap) { if (heap_->write_protect_code_memory()) { heap_->increment_code_space_memory_modification_scope_depth(); heap_->code_space()->SetReadAndWritable(); LargePage* page = heap_->code_lo_space()->first_page(); while (page != nullptr) { DCHECK(page->IsFlagSet(MemoryChunk::IS_EXECUTABLE)); CHECK(heap_->memory_allocator()->IsMemoryChunkExecutable(page)); page->SetReadAndWritable(); page = page->next_page(); } } } CodeSpaceMemoryModificationScope::~CodeSpaceMemoryModificationScope() { if (heap_->write_protect_code_memory()) { heap_->decrement_code_space_memory_modification_scope_depth(); heap_->code_space()->SetDefaultCodePermissions(); LargePage* page = heap_->code_lo_space()->first_page(); while (page != nullptr) { DCHECK(page->IsFlagSet(MemoryChunk::IS_EXECUTABLE)); CHECK(heap_->memory_allocator()->IsMemoryChunkExecutable(page)); page->SetDefaultCodePermissions(); page = page->next_page(); } } } CodePageCollectionMemoryModificationScope:: CodePageCollectionMemoryModificationScope(Heap* heap) : heap_(heap) { if (heap_->write_protect_code_memory() && !heap_->code_space_memory_modification_scope_depth()) { heap_->EnableUnprotectedMemoryChunksRegistry(); } } CodePageCollectionMemoryModificationScope:: ~CodePageCollectionMemoryModificationScope() { if (heap_->write_protect_code_memory() && !heap_->code_space_memory_modification_scope_depth()) { heap_->ProtectUnprotectedMemoryChunks(); heap_->DisableUnprotectedMemoryChunksRegistry(); } } CodePageMemoryModificationScope::CodePageMemoryModificationScope( MemoryChunk* chunk) : chunk_(chunk), scope_active_(chunk_->heap()->write_protect_code_memory() && chunk_->IsFlagSet(MemoryChunk::IS_EXECUTABLE)) { if (scope_active_) { DCHECK(chunk_->owner()->identity() == CODE_SPACE || (chunk_->owner()->identity() == CODE_LO_SPACE)); chunk_->SetReadAndWritable(); } } CodePageMemoryModificationScope::~CodePageMemoryModificationScope() { if (scope_active_) { chunk_->SetDefaultCodePermissions(); } } } // namespace internal } // namespace v8 #endif // V8_HEAP_HEAP_INL_H_