// Copyright 2006-2008 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "v8.h" #include "macro-assembler.h" #include "mark-compact.h" #include "platform.h" namespace v8 { namespace internal { // For contiguous spaces, top should be in the space (or at the end) and limit // should be the end of the space. #define ASSERT_SEMISPACE_ALLOCATION_INFO(info, space) \ ASSERT((space).low() <= (info).top \ && (info).top <= (space).high() \ && (info).limit == (space).high()) // ---------------------------------------------------------------------------- // HeapObjectIterator HeapObjectIterator::HeapObjectIterator(PagedSpace* space) { Initialize(space->bottom(), space->top(), NULL); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, HeapObjectCallback size_func) { Initialize(space->bottom(), space->top(), size_func); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start) { Initialize(start, space->top(), NULL); } HeapObjectIterator::HeapObjectIterator(PagedSpace* space, Address start, HeapObjectCallback size_func) { Initialize(start, space->top(), size_func); } void HeapObjectIterator::Initialize(Address cur, Address end, HeapObjectCallback size_f) { cur_addr_ = cur; end_addr_ = end; end_page_ = Page::FromAllocationTop(end); size_func_ = size_f; Page* p = Page::FromAllocationTop(cur_addr_); cur_limit_ = (p == end_page_) ? end_addr_ : p->AllocationTop(); #ifdef DEBUG Verify(); #endif } bool HeapObjectIterator::HasNextInNextPage() { if (cur_addr_ == end_addr_) return false; Page* cur_page = Page::FromAllocationTop(cur_addr_); cur_page = cur_page->next_page(); ASSERT(cur_page->is_valid()); cur_addr_ = cur_page->ObjectAreaStart(); cur_limit_ = (cur_page == end_page_) ? end_addr_ : cur_page->AllocationTop(); ASSERT(cur_addr_ < cur_limit_); #ifdef DEBUG Verify(); #endif return true; } #ifdef DEBUG void HeapObjectIterator::Verify() { Page* p = Page::FromAllocationTop(cur_addr_); ASSERT(p == Page::FromAllocationTop(cur_limit_)); ASSERT(p->Offset(cur_addr_) <= p->Offset(cur_limit_)); } #endif // ----------------------------------------------------------------------------- // PageIterator PageIterator::PageIterator(PagedSpace* space, Mode mode) : space_(space) { prev_page_ = NULL; switch (mode) { case PAGES_IN_USE: stop_page_ = space->AllocationTopPage(); break; case PAGES_USED_BY_MC: stop_page_ = space->MCRelocationTopPage(); break; case ALL_PAGES: #ifdef DEBUG // Verify that the cached last page in the space is actually the // last page. for (Page* p = space->first_page_; p->is_valid(); p = p->next_page()) { if (!p->next_page()->is_valid()) { ASSERT(space->last_page_ == p); } } #endif stop_page_ = space->last_page_; break; } } // ----------------------------------------------------------------------------- // Page #ifdef DEBUG Page::RSetState Page::rset_state_ = Page::IN_USE; #endif // ----------------------------------------------------------------------------- // MemoryAllocator // int MemoryAllocator::capacity_ = 0; int MemoryAllocator::size_ = 0; VirtualMemory* MemoryAllocator::initial_chunk_ = NULL; // 270 is an estimate based on the static default heap size of a pair of 256K // semispaces and a 64M old generation. const int kEstimatedNumberOfChunks = 270; List MemoryAllocator::chunks_( kEstimatedNumberOfChunks); List MemoryAllocator::free_chunk_ids_(kEstimatedNumberOfChunks); int MemoryAllocator::max_nof_chunks_ = 0; int MemoryAllocator::top_ = 0; void MemoryAllocator::Push(int free_chunk_id) { ASSERT(max_nof_chunks_ > 0); ASSERT(top_ < max_nof_chunks_); free_chunk_ids_[top_++] = free_chunk_id; } int MemoryAllocator::Pop() { ASSERT(top_ > 0); return free_chunk_ids_[--top_]; } bool MemoryAllocator::Setup(int capacity) { capacity_ = RoundUp(capacity, Page::kPageSize); // Over-estimate the size of chunks_ array. It assumes the expansion of old // space is always in the unit of a chunk (kChunkSize) except the last // expansion. // // Due to alignment, allocated space might be one page less than required // number (kPagesPerChunk) of pages for old spaces. // // Reserve two chunk ids for semispaces, one for map space, one for old // space, and one for code space. max_nof_chunks_ = (capacity_ / (kChunkSize - Page::kPageSize)) + 5; if (max_nof_chunks_ > kMaxNofChunks) return false; size_ = 0; ChunkInfo info; // uninitialized element. for (int i = max_nof_chunks_ - 1; i >= 0; i--) { chunks_.Add(info); free_chunk_ids_.Add(i); } top_ = max_nof_chunks_; return true; } void MemoryAllocator::TearDown() { for (int i = 0; i < max_nof_chunks_; i++) { if (chunks_[i].address() != NULL) DeleteChunk(i); } chunks_.Clear(); free_chunk_ids_.Clear(); if (initial_chunk_ != NULL) { LOG(DeleteEvent("InitialChunk", initial_chunk_->address())); delete initial_chunk_; initial_chunk_ = NULL; } ASSERT(top_ == max_nof_chunks_); // all chunks are free top_ = 0; capacity_ = 0; size_ = 0; max_nof_chunks_ = 0; } void* MemoryAllocator::AllocateRawMemory(const size_t requested, size_t* allocated, Executability executable) { if (size_ + static_cast(requested) > capacity_) return NULL; void* mem = OS::Allocate(requested, allocated, executable == EXECUTABLE); int alloced = *allocated; size_ += alloced; Counters::memory_allocated.Increment(alloced); return mem; } void MemoryAllocator::FreeRawMemory(void* mem, size_t length) { OS::Free(mem, length); Counters::memory_allocated.Decrement(length); size_ -= length; ASSERT(size_ >= 0); } void* MemoryAllocator::ReserveInitialChunk(const size_t requested) { ASSERT(initial_chunk_ == NULL); initial_chunk_ = new VirtualMemory(requested); CHECK(initial_chunk_ != NULL); if (!initial_chunk_->IsReserved()) { delete initial_chunk_; initial_chunk_ = NULL; return NULL; } // We are sure that we have mapped a block of requested addresses. ASSERT(initial_chunk_->size() == requested); LOG(NewEvent("InitialChunk", initial_chunk_->address(), requested)); size_ += requested; return initial_chunk_->address(); } static int PagesInChunk(Address start, size_t size) { // The first page starts on the first page-aligned address from start onward // and the last page ends on the last page-aligned address before // start+size. Page::kPageSize is a power of two so we can divide by // shifting. return (RoundDown(start + size, Page::kPageSize) - RoundUp(start, Page::kPageSize)) >> Page::kPageSizeBits; } Page* MemoryAllocator::AllocatePages(int requested_pages, int* allocated_pages, PagedSpace* owner) { if (requested_pages <= 0) return Page::FromAddress(NULL); size_t chunk_size = requested_pages * Page::kPageSize; // There is not enough space to guarantee the desired number pages can be // allocated. if (size_ + static_cast(chunk_size) > capacity_) { // Request as many pages as we can. chunk_size = capacity_ - size_; requested_pages = chunk_size >> Page::kPageSizeBits; if (requested_pages <= 0) return Page::FromAddress(NULL); } void* chunk = AllocateRawMemory(chunk_size, &chunk_size, owner->executable()); if (chunk == NULL) return Page::FromAddress(NULL); LOG(NewEvent("PagedChunk", chunk, chunk_size)); *allocated_pages = PagesInChunk(static_cast
(chunk), chunk_size); if (*allocated_pages == 0) { FreeRawMemory(chunk, chunk_size); LOG(DeleteEvent("PagedChunk", chunk)); return Page::FromAddress(NULL); } int chunk_id = Pop(); chunks_[chunk_id].init(static_cast
(chunk), chunk_size, owner); return InitializePagesInChunk(chunk_id, *allocated_pages, owner); } Page* MemoryAllocator::CommitPages(Address start, size_t size, PagedSpace* owner, int* num_pages) { ASSERT(start != NULL); *num_pages = PagesInChunk(start, size); ASSERT(*num_pages > 0); ASSERT(initial_chunk_ != NULL); ASSERT(InInitialChunk(start)); ASSERT(InInitialChunk(start + size - 1)); if (!initial_chunk_->Commit(start, size, owner->executable() == EXECUTABLE)) { return Page::FromAddress(NULL); } Counters::memory_allocated.Increment(size); // So long as we correctly overestimated the number of chunks we should not // run out of chunk ids. CHECK(!OutOfChunkIds()); int chunk_id = Pop(); chunks_[chunk_id].init(start, size, owner); return InitializePagesInChunk(chunk_id, *num_pages, owner); } bool MemoryAllocator::CommitBlock(Address start, size_t size, Executability executable) { ASSERT(start != NULL); ASSERT(size > 0); ASSERT(initial_chunk_ != NULL); ASSERT(InInitialChunk(start)); ASSERT(InInitialChunk(start + size - 1)); if (!initial_chunk_->Commit(start, size, executable)) return false; Counters::memory_allocated.Increment(size); return true; } Page* MemoryAllocator::InitializePagesInChunk(int chunk_id, int pages_in_chunk, PagedSpace* owner) { ASSERT(IsValidChunk(chunk_id)); ASSERT(pages_in_chunk > 0); Address chunk_start = chunks_[chunk_id].address(); Address low = RoundUp(chunk_start, Page::kPageSize); #ifdef DEBUG size_t chunk_size = chunks_[chunk_id].size(); Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize); ASSERT(pages_in_chunk <= ((OffsetFrom(high) - OffsetFrom(low)) / Page::kPageSize)); #endif Address page_addr = low; for (int i = 0; i < pages_in_chunk; i++) { Page* p = Page::FromAddress(page_addr); p->opaque_header = OffsetFrom(page_addr + Page::kPageSize) | chunk_id; p->is_normal_page = 1; page_addr += Page::kPageSize; } // Set the next page of the last page to 0. Page* last_page = Page::FromAddress(page_addr - Page::kPageSize); last_page->opaque_header = OffsetFrom(0) | chunk_id; return Page::FromAddress(low); } Page* MemoryAllocator::FreePages(Page* p) { if (!p->is_valid()) return p; // Find the first page in the same chunk as 'p' Page* first_page = FindFirstPageInSameChunk(p); Page* page_to_return = Page::FromAddress(NULL); if (p != first_page) { // Find the last page in the same chunk as 'prev'. Page* last_page = FindLastPageInSameChunk(p); first_page = GetNextPage(last_page); // first page in next chunk // set the next_page of last_page to NULL SetNextPage(last_page, Page::FromAddress(NULL)); page_to_return = p; // return 'p' when exiting } while (first_page->is_valid()) { int chunk_id = GetChunkId(first_page); ASSERT(IsValidChunk(chunk_id)); // Find the first page of the next chunk before deleting this chunk. first_page = GetNextPage(FindLastPageInSameChunk(first_page)); // Free the current chunk. DeleteChunk(chunk_id); } return page_to_return; } void MemoryAllocator::DeleteChunk(int chunk_id) { ASSERT(IsValidChunk(chunk_id)); ChunkInfo& c = chunks_[chunk_id]; // We cannot free a chunk contained in the initial chunk because it was not // allocated with AllocateRawMemory. Instead we uncommit the virtual // memory. if (InInitialChunk(c.address())) { // TODO(1240712): VirtualMemory::Uncommit has a return value which // is ignored here. initial_chunk_->Uncommit(c.address(), c.size()); Counters::memory_allocated.Decrement(c.size()); } else { LOG(DeleteEvent("PagedChunk", c.address())); FreeRawMemory(c.address(), c.size()); } c.init(NULL, 0, NULL); Push(chunk_id); } Page* MemoryAllocator::FindFirstPageInSameChunk(Page* p) { int chunk_id = GetChunkId(p); ASSERT(IsValidChunk(chunk_id)); Address low = RoundUp(chunks_[chunk_id].address(), Page::kPageSize); return Page::FromAddress(low); } Page* MemoryAllocator::FindLastPageInSameChunk(Page* p) { int chunk_id = GetChunkId(p); ASSERT(IsValidChunk(chunk_id)); Address chunk_start = chunks_[chunk_id].address(); size_t chunk_size = chunks_[chunk_id].size(); Address high = RoundDown(chunk_start + chunk_size, Page::kPageSize); ASSERT(chunk_start <= p->address() && p->address() < high); return Page::FromAddress(high - Page::kPageSize); } #ifdef DEBUG void MemoryAllocator::ReportStatistics() { float pct = static_cast(capacity_ - size_) / capacity_; PrintF(" capacity: %d, used: %d, available: %%%d\n\n", capacity_, size_, static_cast(pct*100)); } #endif // ----------------------------------------------------------------------------- // PagedSpace implementation PagedSpace::PagedSpace(int max_capacity, AllocationSpace id, Executability executable) : Space(id, executable) { max_capacity_ = (RoundDown(max_capacity, Page::kPageSize) / Page::kPageSize) * Page::kObjectAreaSize; accounting_stats_.Clear(); allocation_info_.top = NULL; allocation_info_.limit = NULL; mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; } bool PagedSpace::Setup(Address start, size_t size) { if (HasBeenSetup()) return false; int num_pages = 0; // Try to use the virtual memory range passed to us. If it is too small to // contain at least one page, ignore it and allocate instead. int pages_in_chunk = PagesInChunk(start, size); if (pages_in_chunk > 0) { first_page_ = MemoryAllocator::CommitPages(RoundUp(start, Page::kPageSize), Page::kPageSize * pages_in_chunk, this, &num_pages); } else { int requested_pages = Min(MemoryAllocator::kPagesPerChunk, max_capacity_ / Page::kObjectAreaSize); first_page_ = MemoryAllocator::AllocatePages(requested_pages, &num_pages, this); if (!first_page_->is_valid()) return false; } // We are sure that the first page is valid and that we have at least one // page. ASSERT(first_page_->is_valid()); ASSERT(num_pages > 0); accounting_stats_.ExpandSpace(num_pages * Page::kObjectAreaSize); ASSERT(Capacity() <= max_capacity_); // Sequentially initialize remembered sets in the newly allocated // pages and cache the current last page in the space. for (Page* p = first_page_; p->is_valid(); p = p->next_page()) { p->ClearRSet(); last_page_ = p; } // Use first_page_ for allocation. SetAllocationInfo(&allocation_info_, first_page_); return true; } bool PagedSpace::HasBeenSetup() { return (Capacity() > 0); } void PagedSpace::TearDown() { first_page_ = MemoryAllocator::FreePages(first_page_); ASSERT(!first_page_->is_valid()); accounting_stats_.Clear(); } #ifdef ENABLE_HEAP_PROTECTION void PagedSpace::Protect() { Page* page = first_page_; while (page->is_valid()) { MemoryAllocator::ProtectChunkFromPage(page); page = MemoryAllocator::FindLastPageInSameChunk(page)->next_page(); } } void PagedSpace::Unprotect() { Page* page = first_page_; while (page->is_valid()) { MemoryAllocator::UnprotectChunkFromPage(page); page = MemoryAllocator::FindLastPageInSameChunk(page)->next_page(); } } #endif void PagedSpace::ClearRSet() { PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { it.next()->ClearRSet(); } } Object* PagedSpace::FindObject(Address addr) { // Note: this function can only be called before or after mark-compact GC // because it accesses map pointers. ASSERT(!MarkCompactCollector::in_use()); if (!Contains(addr)) return Failure::Exception(); Page* p = Page::FromAddress(addr); ASSERT(IsUsed(p)); Address cur = p->ObjectAreaStart(); Address end = p->AllocationTop(); while (cur < end) { HeapObject* obj = HeapObject::FromAddress(cur); Address next = cur + obj->Size(); if ((cur <= addr) && (addr < next)) return obj; cur = next; } UNREACHABLE(); return Failure::Exception(); } bool PagedSpace::IsUsed(Page* page) { PageIterator it(this, PageIterator::PAGES_IN_USE); while (it.has_next()) { if (page == it.next()) return true; } return false; } void PagedSpace::SetAllocationInfo(AllocationInfo* alloc_info, Page* p) { alloc_info->top = p->ObjectAreaStart(); alloc_info->limit = p->ObjectAreaEnd(); ASSERT(alloc_info->VerifyPagedAllocation()); } void PagedSpace::MCResetRelocationInfo() { // Set page indexes. int i = 0; PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { Page* p = it.next(); p->mc_page_index = i++; } // Set mc_forwarding_info_ to the first page in the space. SetAllocationInfo(&mc_forwarding_info_, first_page_); // All the bytes in the space are 'available'. We will rediscover // allocated and wasted bytes during GC. accounting_stats_.Reset(); } int PagedSpace::MCSpaceOffsetForAddress(Address addr) { #ifdef DEBUG // The Contains function considers the address at the beginning of a // page in the page, MCSpaceOffsetForAddress considers it is in the // previous page. if (Page::IsAlignedToPageSize(addr)) { ASSERT(Contains(addr - kPointerSize)); } else { ASSERT(Contains(addr)); } #endif // If addr is at the end of a page, it belongs to previous page Page* p = Page::IsAlignedToPageSize(addr) ? Page::FromAllocationTop(addr) : Page::FromAddress(addr); int index = p->mc_page_index; return (index * Page::kPageSize) + p->Offset(addr); } // Slow case for reallocating and promoting objects during a compacting // collection. This function is not space-specific. HeapObject* PagedSpace::SlowMCAllocateRaw(int size_in_bytes) { Page* current_page = TopPageOf(mc_forwarding_info_); if (!current_page->next_page()->is_valid()) { if (!Expand(current_page)) { return NULL; } } // There are surely more pages in the space now. ASSERT(current_page->next_page()->is_valid()); // We do not add the top of page block for current page to the space's // free list---the block may contain live objects so we cannot write // bookkeeping information to it. Instead, we will recover top of page // blocks when we move objects to their new locations. // // We do however write the allocation pointer to the page. The encoding // of forwarding addresses is as an offset in terms of live bytes, so we // need quick access to the allocation top of each page to decode // forwarding addresses. current_page->mc_relocation_top = mc_forwarding_info_.top; SetAllocationInfo(&mc_forwarding_info_, current_page->next_page()); return AllocateLinearly(&mc_forwarding_info_, size_in_bytes); } bool PagedSpace::Expand(Page* last_page) { ASSERT(max_capacity_ % Page::kObjectAreaSize == 0); ASSERT(Capacity() % Page::kObjectAreaSize == 0); if (Capacity() == max_capacity_) return false; ASSERT(Capacity() < max_capacity_); // Last page must be valid and its next page is invalid. ASSERT(last_page->is_valid() && !last_page->next_page()->is_valid()); int available_pages = (max_capacity_ - Capacity()) / Page::kObjectAreaSize; if (available_pages <= 0) return false; int desired_pages = Min(available_pages, MemoryAllocator::kPagesPerChunk); Page* p = MemoryAllocator::AllocatePages(desired_pages, &desired_pages, this); if (!p->is_valid()) return false; accounting_stats_.ExpandSpace(desired_pages * Page::kObjectAreaSize); ASSERT(Capacity() <= max_capacity_); MemoryAllocator::SetNextPage(last_page, p); // Sequentially clear remembered set of new pages and and cache the // new last page in the space. while (p->is_valid()) { p->ClearRSet(); last_page_ = p; p = p->next_page(); } return true; } #ifdef DEBUG int PagedSpace::CountTotalPages() { int count = 0; for (Page* p = first_page_; p->is_valid(); p = p->next_page()) { count++; } return count; } #endif void PagedSpace::Shrink() { // Release half of free pages. Page* top_page = AllocationTopPage(); ASSERT(top_page->is_valid()); // Loop over the pages from the top page to the end of the space to count // the number of pages to keep and find the last page to keep. int free_pages = 0; int pages_to_keep = 0; // Of the free pages. Page* last_page_to_keep = top_page; Page* current_page = top_page->next_page(); // Loop over the pages to the end of the space. while (current_page->is_valid()) { #if defined(ANDROID) // Free all chunks if possible #else // Advance last_page_to_keep every other step to end up at the midpoint. if ((free_pages & 0x1) == 1) { pages_to_keep++; last_page_to_keep = last_page_to_keep->next_page(); } #endif free_pages++; current_page = current_page->next_page(); } // Free pages after last_page_to_keep, and adjust the next_page link. Page* p = MemoryAllocator::FreePages(last_page_to_keep->next_page()); MemoryAllocator::SetNextPage(last_page_to_keep, p); // Since pages are only freed in whole chunks, we may have kept more // than pages_to_keep. Count the extra pages and cache the new last // page in the space. last_page_ = last_page_to_keep; while (p->is_valid()) { pages_to_keep++; last_page_ = p; p = p->next_page(); } // The difference between free_pages and pages_to_keep is the number of // pages actually freed. ASSERT(pages_to_keep <= free_pages); int bytes_freed = (free_pages - pages_to_keep) * Page::kObjectAreaSize; accounting_stats_.ShrinkSpace(bytes_freed); ASSERT(Capacity() == CountTotalPages() * Page::kObjectAreaSize); } bool PagedSpace::EnsureCapacity(int capacity) { if (Capacity() >= capacity) return true; // Start from the allocation top and loop to the last page in the space. Page* last_page = AllocationTopPage(); Page* next_page = last_page->next_page(); while (next_page->is_valid()) { last_page = MemoryAllocator::FindLastPageInSameChunk(next_page); next_page = last_page->next_page(); } // Expand the space until it has the required capacity or expansion fails. do { if (!Expand(last_page)) return false; ASSERT(last_page->next_page()->is_valid()); last_page = MemoryAllocator::FindLastPageInSameChunk(last_page->next_page()); } while (Capacity() < capacity); return true; } #ifdef DEBUG void PagedSpace::Print() { } #endif #ifdef DEBUG // We do not assume that the PageIterator works, because it depends on the // invariants we are checking during verification. void PagedSpace::Verify(ObjectVisitor* visitor) { // The allocation pointer should be valid, and it should be in a page in the // space. ASSERT(allocation_info_.VerifyPagedAllocation()); Page* top_page = Page::FromAllocationTop(allocation_info_.top); ASSERT(MemoryAllocator::IsPageInSpace(top_page, this)); // Loop over all the pages. bool above_allocation_top = false; Page* current_page = first_page_; while (current_page->is_valid()) { if (above_allocation_top) { // We don't care what's above the allocation top. } else { // Unless this is the last page in the space containing allocated // objects, the allocation top should be at a constant offset from the // object area end. Address top = current_page->AllocationTop(); if (current_page == top_page) { ASSERT(top == allocation_info_.top); // The next page will be above the allocation top. above_allocation_top = true; } else { ASSERT(top == current_page->ObjectAreaEnd() - page_extra_); } // It should be packed with objects from the bottom to the top. Address current = current_page->ObjectAreaStart(); while (current < top) { HeapObject* object = HeapObject::FromAddress(current); // The first word should be a map, and we expect all map pointers to // be in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(Heap::map_space()->Contains(map)); // Perform space-specific object verification. VerifyObject(object); // The object itself should look OK. object->Verify(); // All the interior pointers should be contained in the heap and // have their remembered set bits set if required as determined // by the visitor. int size = object->Size(); if (object->IsCode()) { Code::cast(object)->ConvertICTargetsFromAddressToObject(); object->IterateBody(map->instance_type(), size, visitor); Code::cast(object)->ConvertICTargetsFromObjectToAddress(); } else { object->IterateBody(map->instance_type(), size, visitor); } current += size; } // The allocation pointer should not be in the middle of an object. ASSERT(current == top); } current_page = current_page->next_page(); } } #endif // ----------------------------------------------------------------------------- // NewSpace implementation bool NewSpace::Setup(Address start, int size) { // Setup new space based on the preallocated memory block defined by // start and size. The provided space is divided into two semi-spaces. // To support fast containment testing in the new space, the size of // this chunk must be a power of two and it must be aligned to its size. int initial_semispace_capacity = Heap::InitialSemiSpaceSize(); int maximum_semispace_capacity = Heap::SemiSpaceSize(); ASSERT(initial_semispace_capacity <= maximum_semispace_capacity); ASSERT(IsPowerOf2(maximum_semispace_capacity)); maximum_capacity_ = maximum_semispace_capacity; capacity_ = initial_semispace_capacity; // Allocate and setup the histogram arrays if necessary. #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING) allocated_histogram_ = NewArray(LAST_TYPE + 1); promoted_histogram_ = NewArray(LAST_TYPE + 1); #define SET_NAME(name) allocated_histogram_[name].set_name(#name); \ promoted_histogram_[name].set_name(#name); INSTANCE_TYPE_LIST(SET_NAME) #undef SET_NAME #endif ASSERT(size == 2 * maximum_capacity_); ASSERT(IsAddressAligned(start, size, 0)); if (!to_space_.Setup(start, capacity_, maximum_capacity_)) { return false; } if (!from_space_.Setup(start + maximum_capacity_, capacity_, maximum_capacity_)) { return false; } start_ = start; address_mask_ = ~(size - 1); object_mask_ = address_mask_ | kHeapObjectTag; object_expected_ = reinterpret_cast(start) | kHeapObjectTag; allocation_info_.top = to_space_.low(); allocation_info_.limit = to_space_.high(); mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); return true; } void NewSpace::TearDown() { #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING) if (allocated_histogram_) { DeleteArray(allocated_histogram_); allocated_histogram_ = NULL; } if (promoted_histogram_) { DeleteArray(promoted_histogram_); promoted_histogram_ = NULL; } #endif start_ = NULL; capacity_ = 0; allocation_info_.top = NULL; allocation_info_.limit = NULL; mc_forwarding_info_.top = NULL; mc_forwarding_info_.limit = NULL; to_space_.TearDown(); from_space_.TearDown(); } #ifdef ENABLE_HEAP_PROTECTION void NewSpace::Protect() { MemoryAllocator::Protect(ToSpaceLow(), Capacity()); MemoryAllocator::Protect(FromSpaceLow(), Capacity()); } void NewSpace::Unprotect() { MemoryAllocator::Unprotect(ToSpaceLow(), Capacity(), to_space_.executable()); MemoryAllocator::Unprotect(FromSpaceLow(), Capacity(), from_space_.executable()); } #endif void NewSpace::Flip() { SemiSpace tmp = from_space_; from_space_ = to_space_; to_space_ = tmp; } bool NewSpace::Grow() { ASSERT(capacity_ < maximum_capacity_); // TODO(1240712): Failure to double the from space can result in // semispaces of different sizes. In the event of that failure, the // to space doubling should be rolled back before returning false. if (!to_space_.Grow() || !from_space_.Grow()) return false; capacity_ = to_space_.Capacity() + from_space_.Capacity(); allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); return true; } void NewSpace::ResetAllocationInfo() { allocation_info_.top = to_space_.low(); allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } void NewSpace::MCResetRelocationInfo() { mc_forwarding_info_.top = from_space_.low(); mc_forwarding_info_.limit = from_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(mc_forwarding_info_, from_space_); } void NewSpace::MCCommitRelocationInfo() { // Assumes that the spaces have been flipped so that mc_forwarding_info_ is // valid allocation info for the to space. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = to_space_.high(); ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); } #ifdef DEBUG // We do not use the SemispaceIterator because verification doesn't assume // that it works (it depends on the invariants we are checking). void NewSpace::Verify() { // The allocation pointer should be in the space or at the very end. ASSERT_SEMISPACE_ALLOCATION_INFO(allocation_info_, to_space_); // There should be objects packed in from the low address up to the // allocation pointer. Address current = to_space_.low(); while (current < top()) { HeapObject* object = HeapObject::FromAddress(current); // The first word should be a map, and we expect all map pointers to // be in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(Heap::map_space()->Contains(map)); // The object should not be code or a map. ASSERT(!object->IsMap()); ASSERT(!object->IsCode()); // The object itself should look OK. object->Verify(); // All the interior pointers should be contained in the heap. VerifyPointersVisitor visitor; int size = object->Size(); object->IterateBody(map->instance_type(), size, &visitor); current += size; } // The allocation pointer should not be in the middle of an object. ASSERT(current == top()); } #endif // ----------------------------------------------------------------------------- // SemiSpace implementation bool SemiSpace::Setup(Address start, int initial_capacity, int maximum_capacity) { // Creates a space in the young generation. The constructor does not // allocate memory from the OS. A SemiSpace is given a contiguous chunk of // memory of size 'capacity' when set up, and does not grow or shrink // otherwise. In the mark-compact collector, the memory region of the from // space is used as the marking stack. It requires contiguous memory // addresses. capacity_ = initial_capacity; maximum_capacity_ = maximum_capacity; if (!MemoryAllocator::CommitBlock(start, capacity_, executable())) { return false; } start_ = start; address_mask_ = ~(maximum_capacity - 1); object_mask_ = address_mask_ | kHeapObjectTag; object_expected_ = reinterpret_cast(start) | kHeapObjectTag; age_mark_ = start_; return true; } void SemiSpace::TearDown() { start_ = NULL; capacity_ = 0; } bool SemiSpace::Grow() { // Commit 50% extra space but only up to maximum capacity. int extra = capacity_/2; if (capacity_ + extra > maximum_capacity_) { extra = maximum_capacity_ - capacity_; } if (!MemoryAllocator::CommitBlock(high(), extra, executable())) { return false; } capacity_ += extra; return true; } #ifdef DEBUG void SemiSpace::Print() { } void SemiSpace::Verify() { } #endif // ----------------------------------------------------------------------------- // SemiSpaceIterator implementation. SemiSpaceIterator::SemiSpaceIterator(NewSpace* space) { Initialize(space, space->bottom(), space->top(), NULL); } SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, HeapObjectCallback size_func) { Initialize(space, space->bottom(), space->top(), size_func); } SemiSpaceIterator::SemiSpaceIterator(NewSpace* space, Address start) { Initialize(space, start, space->top(), NULL); } void SemiSpaceIterator::Initialize(NewSpace* space, Address start, Address end, HeapObjectCallback size_func) { ASSERT(space->ToSpaceContains(start)); ASSERT(space->ToSpaceLow() <= end && end <= space->ToSpaceHigh()); space_ = &space->to_space_; current_ = start; limit_ = end; size_func_ = size_func; } #ifdef DEBUG // A static array of histogram info for each type. static HistogramInfo heap_histograms[LAST_TYPE+1]; static JSObject::SpillInformation js_spill_information; // heap_histograms is shared, always clear it before using it. static void ClearHistograms() { // We reset the name each time, though it hasn't changed. #define DEF_TYPE_NAME(name) heap_histograms[name].set_name(#name); INSTANCE_TYPE_LIST(DEF_TYPE_NAME) #undef DEF_TYPE_NAME #define CLEAR_HISTOGRAM(name) heap_histograms[name].clear(); INSTANCE_TYPE_LIST(CLEAR_HISTOGRAM) #undef CLEAR_HISTOGRAM js_spill_information.Clear(); } static int code_kind_statistics[Code::NUMBER_OF_KINDS]; static void ClearCodeKindStatistics() { for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { code_kind_statistics[i] = 0; } } static void ReportCodeKindStatistics() { const char* table[Code::NUMBER_OF_KINDS]; #define CASE(name) \ case Code::name: table[Code::name] = #name; \ break for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { switch (static_cast(i)) { CASE(FUNCTION); CASE(STUB); CASE(BUILTIN); CASE(LOAD_IC); CASE(KEYED_LOAD_IC); CASE(STORE_IC); CASE(KEYED_STORE_IC); CASE(CALL_IC); } } #undef CASE PrintF("\n Code kind histograms: \n"); for (int i = 0; i < Code::NUMBER_OF_KINDS; i++) { if (code_kind_statistics[i] > 0) { PrintF(" %-20s: %10d bytes\n", table[i], code_kind_statistics[i]); } } PrintF("\n"); } static int CollectHistogramInfo(HeapObject* obj) { InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); ASSERT(heap_histograms[type].name() != NULL); heap_histograms[type].increment_number(1); heap_histograms[type].increment_bytes(obj->Size()); if (FLAG_collect_heap_spill_statistics && obj->IsJSObject()) { JSObject::cast(obj)->IncrementSpillStatistics(&js_spill_information); } return obj->Size(); } static void ReportHistogram(bool print_spill) { PrintF("\n Object Histogram:\n"); for (int i = 0; i <= LAST_TYPE; i++) { if (heap_histograms[i].number() > 0) { PrintF(" %-33s%10d (%10d bytes)\n", heap_histograms[i].name(), heap_histograms[i].number(), heap_histograms[i].bytes()); } } PrintF("\n"); // Summarize string types. int string_number = 0; int string_bytes = 0; #define INCREMENT(type, size, name, camel_name) \ string_number += heap_histograms[type].number(); \ string_bytes += heap_histograms[type].bytes(); STRING_TYPE_LIST(INCREMENT) #undef INCREMENT if (string_number > 0) { PrintF(" %-33s%10d (%10d bytes)\n\n", "STRING_TYPE", string_number, string_bytes); } if (FLAG_collect_heap_spill_statistics && print_spill) { js_spill_information.Print(); } } #endif // DEBUG // Support for statistics gathering for --heap-stats and --log-gc. #if defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING) void NewSpace::ClearHistograms() { for (int i = 0; i <= LAST_TYPE; i++) { allocated_histogram_[i].clear(); promoted_histogram_[i].clear(); } } // Because the copying collector does not touch garbage objects, we iterate // the new space before a collection to get a histogram of allocated objects. // This only happens (1) when compiled with DEBUG and the --heap-stats flag is // set, or when compiled with ENABLE_LOGGING_AND_PROFILING and the --log-gc // flag is set. void NewSpace::CollectStatistics() { ClearHistograms(); SemiSpaceIterator it(this); while (it.has_next()) RecordAllocation(it.next()); } #ifdef ENABLE_LOGGING_AND_PROFILING static void DoReportStatistics(HistogramInfo* info, const char* description) { LOG(HeapSampleBeginEvent("NewSpace", description)); // Lump all the string types together. int string_number = 0; int string_bytes = 0; #define INCREMENT(type, size, name, camel_name) \ string_number += info[type].number(); \ string_bytes += info[type].bytes(); STRING_TYPE_LIST(INCREMENT) #undef INCREMENT if (string_number > 0) { LOG(HeapSampleItemEvent("STRING_TYPE", string_number, string_bytes)); } // Then do the other types. for (int i = FIRST_NONSTRING_TYPE; i <= LAST_TYPE; ++i) { if (info[i].number() > 0) { LOG(HeapSampleItemEvent(info[i].name(), info[i].number(), info[i].bytes())); } } LOG(HeapSampleEndEvent("NewSpace", description)); } #endif // ENABLE_LOGGING_AND_PROFILING void NewSpace::ReportStatistics() { #ifdef DEBUG if (FLAG_heap_stats) { float pct = static_cast(Available()) / Capacity(); PrintF(" capacity: %d, available: %d, %%%d\n", Capacity(), Available(), static_cast(pct*100)); PrintF("\n Object Histogram:\n"); for (int i = 0; i <= LAST_TYPE; i++) { if (allocated_histogram_[i].number() > 0) { PrintF(" %-33s%10d (%10d bytes)\n", allocated_histogram_[i].name(), allocated_histogram_[i].number(), allocated_histogram_[i].bytes()); } } PrintF("\n"); } #endif // DEBUG #ifdef ENABLE_LOGGING_AND_PROFILING if (FLAG_log_gc) { DoReportStatistics(allocated_histogram_, "allocated"); DoReportStatistics(promoted_histogram_, "promoted"); } #endif // ENABLE_LOGGING_AND_PROFILING } void NewSpace::RecordAllocation(HeapObject* obj) { InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); allocated_histogram_[type].increment_number(1); allocated_histogram_[type].increment_bytes(obj->Size()); } void NewSpace::RecordPromotion(HeapObject* obj) { InstanceType type = obj->map()->instance_type(); ASSERT(0 <= type && type <= LAST_TYPE); promoted_histogram_[type].increment_number(1); promoted_histogram_[type].increment_bytes(obj->Size()); } #endif // defined(DEBUG) || defined(ENABLE_LOGGING_AND_PROFILING) // ----------------------------------------------------------------------------- // Free lists for old object spaces implementation void FreeListNode::set_size(int size_in_bytes) { ASSERT(size_in_bytes > 0); ASSERT(IsAligned(size_in_bytes, kPointerSize)); // We write a map and possibly size information to the block. If the block // is big enough to be a ByteArray with at least one extra word (the next // pointer), we set its map to be the byte array map and its size to an // appropriate array length for the desired size from HeapObject::Size(). // If the block is too small (eg, one or two words), to hold both a size // field and a next pointer, we give it a filler map that gives it the // correct size. if (size_in_bytes > ByteArray::kAlignedSize) { set_map(Heap::raw_unchecked_byte_array_map()); ByteArray::cast(this)->set_length(ByteArray::LengthFor(size_in_bytes)); } else if (size_in_bytes == kPointerSize) { set_map(Heap::raw_unchecked_one_pointer_filler_map()); } else if (size_in_bytes == 2 * kPointerSize) { set_map(Heap::raw_unchecked_two_pointer_filler_map()); } else { UNREACHABLE(); } ASSERT(Size() == size_in_bytes); } Address FreeListNode::next() { ASSERT(map() == Heap::raw_unchecked_byte_array_map() || map() == Heap::raw_unchecked_two_pointer_filler_map()); if (map() == Heap::raw_unchecked_byte_array_map()) { ASSERT(Size() >= kNextOffset + kPointerSize); return Memory::Address_at(address() + kNextOffset); } else { return Memory::Address_at(address() + kPointerSize); } } void FreeListNode::set_next(Address next) { ASSERT(map() == Heap::raw_unchecked_byte_array_map() || map() == Heap::raw_unchecked_two_pointer_filler_map()); if (map() == Heap::raw_unchecked_byte_array_map()) { ASSERT(Size() >= kNextOffset + kPointerSize); Memory::Address_at(address() + kNextOffset) = next; } else { Memory::Address_at(address() + kPointerSize) = next; } } OldSpaceFreeList::OldSpaceFreeList(AllocationSpace owner) : owner_(owner) { Reset(); } void OldSpaceFreeList::Reset() { available_ = 0; for (int i = 0; i < kFreeListsLength; i++) { free_[i].head_node_ = NULL; } needs_rebuild_ = false; finger_ = kHead; free_[kHead].next_size_ = kEnd; } void OldSpaceFreeList::RebuildSizeList() { ASSERT(needs_rebuild_); int cur = kHead; for (int i = cur + 1; i < kFreeListsLength; i++) { if (free_[i].head_node_ != NULL) { free_[cur].next_size_ = i; cur = i; } } free_[cur].next_size_ = kEnd; needs_rebuild_ = false; } int OldSpaceFreeList::Free(Address start, int size_in_bytes) { #ifdef DEBUG for (int i = 0; i < size_in_bytes; i += kPointerSize) { Memory::Address_at(start + i) = kZapValue; } #endif FreeListNode* node = FreeListNode::FromAddress(start); node->set_size(size_in_bytes); // We don't use the freelists in compacting mode. This makes it more like a // GC that only has mark-sweep-compact and doesn't have a mark-sweep // collector. if (FLAG_always_compact) { return size_in_bytes; } // Early return to drop too-small blocks on the floor (one or two word // blocks cannot hold a map pointer, a size field, and a pointer to the // next block in the free list). if (size_in_bytes < kMinBlockSize) { return size_in_bytes; } // Insert other blocks at the head of an exact free list. int index = size_in_bytes >> kPointerSizeLog2; node->set_next(free_[index].head_node_); free_[index].head_node_ = node->address(); available_ += size_in_bytes; needs_rebuild_ = true; return 0; } Object* OldSpaceFreeList::Allocate(int size_in_bytes, int* wasted_bytes) { ASSERT(0 < size_in_bytes); ASSERT(size_in_bytes <= kMaxBlockSize); ASSERT(IsAligned(size_in_bytes, kPointerSize)); if (needs_rebuild_) RebuildSizeList(); int index = size_in_bytes >> kPointerSizeLog2; // Check for a perfect fit. if (free_[index].head_node_ != NULL) { FreeListNode* node = FreeListNode::FromAddress(free_[index].head_node_); // If this was the last block of its size, remove the size. if ((free_[index].head_node_ = node->next()) == NULL) RemoveSize(index); available_ -= size_in_bytes; *wasted_bytes = 0; ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. return node; } // Search the size list for the best fit. int prev = finger_ < index ? finger_ : kHead; int cur = FindSize(index, &prev); ASSERT(index < cur); if (cur == kEnd) { // No large enough size in list. *wasted_bytes = 0; return Failure::RetryAfterGC(size_in_bytes, owner_); } ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. int rem = cur - index; int rem_bytes = rem << kPointerSizeLog2; FreeListNode* cur_node = FreeListNode::FromAddress(free_[cur].head_node_); ASSERT(cur_node->Size() == (cur << kPointerSizeLog2)); FreeListNode* rem_node = FreeListNode::FromAddress(free_[cur].head_node_ + size_in_bytes); // Distinguish the cases prev < rem < cur and rem <= prev < cur // to avoid many redundant tests and calls to Insert/RemoveSize. if (prev < rem) { // Simple case: insert rem between prev and cur. finger_ = prev; free_[prev].next_size_ = rem; // If this was the last block of size cur, remove the size. if ((free_[cur].head_node_ = cur_node->next()) == NULL) { free_[rem].next_size_ = free_[cur].next_size_; } else { free_[rem].next_size_ = cur; } // Add the remainder block. rem_node->set_size(rem_bytes); rem_node->set_next(free_[rem].head_node_); free_[rem].head_node_ = rem_node->address(); } else { // If this was the last block of size cur, remove the size. if ((free_[cur].head_node_ = cur_node->next()) == NULL) { finger_ = prev; free_[prev].next_size_ = free_[cur].next_size_; } if (rem_bytes < kMinBlockSize) { // Too-small remainder is wasted. rem_node->set_size(rem_bytes); available_ -= size_in_bytes + rem_bytes; *wasted_bytes = rem_bytes; return cur_node; } // Add the remainder block and, if needed, insert its size. rem_node->set_size(rem_bytes); rem_node->set_next(free_[rem].head_node_); free_[rem].head_node_ = rem_node->address(); if (rem_node->next() == NULL) InsertSize(rem); } available_ -= size_in_bytes; *wasted_bytes = 0; return cur_node; } #ifdef DEBUG bool OldSpaceFreeList::Contains(FreeListNode* node) { for (int i = 0; i < kFreeListsLength; i++) { Address cur_addr = free_[i].head_node_; while (cur_addr != NULL) { FreeListNode* cur_node = FreeListNode::FromAddress(cur_addr); if (cur_node == node) return true; cur_addr = cur_node->next(); } } return false; } #endif FixedSizeFreeList::FixedSizeFreeList(AllocationSpace owner, int object_size) : owner_(owner), object_size_(object_size) { Reset(); } void FixedSizeFreeList::Reset() { available_ = 0; head_ = NULL; } void FixedSizeFreeList::Free(Address start) { #ifdef DEBUG for (int i = 0; i < object_size_; i += kPointerSize) { Memory::Address_at(start + i) = kZapValue; } #endif ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. FreeListNode* node = FreeListNode::FromAddress(start); node->set_size(object_size_); node->set_next(head_); head_ = node->address(); available_ += object_size_; } Object* FixedSizeFreeList::Allocate() { if (head_ == NULL) { return Failure::RetryAfterGC(object_size_, owner_); } ASSERT(!FLAG_always_compact); // We only use the freelists with mark-sweep. FreeListNode* node = FreeListNode::FromAddress(head_); head_ = node->next(); available_ -= object_size_; return node; } // ----------------------------------------------------------------------------- // OldSpace implementation void OldSpace::PrepareForMarkCompact(bool will_compact) { if (will_compact) { // Reset relocation info. During a compacting collection, everything in // the space is considered 'available' and we will rediscover live data // and waste during the collection. MCResetRelocationInfo(); ASSERT(Available() == Capacity()); } else { // During a non-compacting collection, everything below the linear // allocation pointer is considered allocated (everything above is // available) and we will rediscover available and wasted bytes during // the collection. accounting_stats_.AllocateBytes(free_list_.available()); accounting_stats_.FillWastedBytes(Waste()); } // Clear the free list before a full GC---it will be rebuilt afterward. free_list_.Reset(); } void OldSpace::MCCommitRelocationInfo() { // Update fast allocation info. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = mc_forwarding_info_.limit; ASSERT(allocation_info_.VerifyPagedAllocation()); // The space is compacted and we haven't yet built free lists or // wasted any space. ASSERT(Waste() == 0); ASSERT(AvailableFree() == 0); // Build the free list for the space. int computed_size = 0; PageIterator it(this, PageIterator::PAGES_USED_BY_MC); while (it.has_next()) { Page* p = it.next(); // Space below the relocation pointer is allocated. computed_size += p->mc_relocation_top - p->ObjectAreaStart(); if (it.has_next()) { // Free the space at the top of the page. We cannot use // p->mc_relocation_top after the call to Free (because Free will clear // remembered set bits). int extra_size = p->ObjectAreaEnd() - p->mc_relocation_top; if (extra_size > 0) { int wasted_bytes = free_list_.Free(p->mc_relocation_top, extra_size); // The bytes we have just "freed" to add to the free list were // already accounted as available. accounting_stats_.WasteBytes(wasted_bytes); } } } // Make sure the computed size - based on the used portion of the pages in // use - matches the size obtained while computing forwarding addresses. ASSERT(computed_size == Size()); } // Slow case for normal allocation. Try in order: (1) allocate in the next // page in the space, (2) allocate off the space's free list, (3) expand the // space, (4) fail. HeapObject* OldSpace::SlowAllocateRaw(int size_in_bytes) { // Linear allocation in this space has failed. If there is another page // in the space, move to that page and allocate there. This allocation // should succeed (size_in_bytes should not be greater than a page's // object area size). Page* current_page = TopPageOf(allocation_info_); if (current_page->next_page()->is_valid()) { return AllocateInNextPage(current_page, size_in_bytes); } // There is no next page in this space. Try free list allocation. int wasted_bytes; Object* result = free_list_.Allocate(size_in_bytes, &wasted_bytes); accounting_stats_.WasteBytes(wasted_bytes); if (!result->IsFailure()) { accounting_stats_.AllocateBytes(size_in_bytes); return HeapObject::cast(result); } // Free list allocation failed and there is no next page. Fail if we have // hit the old generation size limit that should cause a garbage // collection. if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) { return NULL; } // Try to expand the space and allocate in the new next page. ASSERT(!current_page->next_page()->is_valid()); if (Expand(current_page)) { return AllocateInNextPage(current_page, size_in_bytes); } // Finally, fail. return NULL; } // Add the block at the top of the page to the space's free list, set the // allocation info to the next page (assumed to be one), and allocate // linearly there. HeapObject* OldSpace::AllocateInNextPage(Page* current_page, int size_in_bytes) { ASSERT(current_page->next_page()->is_valid()); // Add the block at the top of this page to the free list. int free_size = current_page->ObjectAreaEnd() - allocation_info_.top; if (free_size > 0) { int wasted_bytes = free_list_.Free(allocation_info_.top, free_size); accounting_stats_.WasteBytes(wasted_bytes); } SetAllocationInfo(&allocation_info_, current_page->next_page()); return AllocateLinearly(&allocation_info_, size_in_bytes); } #ifdef DEBUG struct CommentStatistic { const char* comment; int size; int count; void Clear() { comment = NULL; size = 0; count = 0; } }; // must be small, since an iteration is used for lookup const int kMaxComments = 64; static CommentStatistic comments_statistics[kMaxComments+1]; void PagedSpace::ReportCodeStatistics() { ReportCodeKindStatistics(); PrintF("Code comment statistics (\" [ comment-txt : size/ " "count (average)\"):\n"); for (int i = 0; i <= kMaxComments; i++) { const CommentStatistic& cs = comments_statistics[i]; if (cs.size > 0) { PrintF(" %-30s: %10d/%6d (%d)\n", cs.comment, cs.size, cs.count, cs.size/cs.count); } } PrintF("\n"); } void PagedSpace::ResetCodeStatistics() { ClearCodeKindStatistics(); for (int i = 0; i < kMaxComments; i++) comments_statistics[i].Clear(); comments_statistics[kMaxComments].comment = "Unknown"; comments_statistics[kMaxComments].size = 0; comments_statistics[kMaxComments].count = 0; } // Adds comment to 'comment_statistics' table. Performance OK sa long as // 'kMaxComments' is small static void EnterComment(const char* comment, int delta) { // Do not count empty comments if (delta <= 0) return; CommentStatistic* cs = &comments_statistics[kMaxComments]; // Search for a free or matching entry in 'comments_statistics': 'cs' // points to result. for (int i = 0; i < kMaxComments; i++) { if (comments_statistics[i].comment == NULL) { cs = &comments_statistics[i]; cs->comment = comment; break; } else if (strcmp(comments_statistics[i].comment, comment) == 0) { cs = &comments_statistics[i]; break; } } // Update entry for 'comment' cs->size += delta; cs->count += 1; } // Call for each nested comment start (start marked with '[ xxx', end marked // with ']'. RelocIterator 'it' must point to a comment reloc info. static void CollectCommentStatistics(RelocIterator* it) { ASSERT(!it->done()); ASSERT(it->rinfo()->rmode() == RelocInfo::COMMENT); const char* tmp = reinterpret_cast(it->rinfo()->data()); if (tmp[0] != '[') { // Not a nested comment; skip return; } // Search for end of nested comment or a new nested comment const char* const comment_txt = reinterpret_cast(it->rinfo()->data()); const byte* prev_pc = it->rinfo()->pc(); int flat_delta = 0; it->next(); while (true) { // All nested comments must be terminated properly, and therefore exit // from loop. ASSERT(!it->done()); if (it->rinfo()->rmode() == RelocInfo::COMMENT) { const char* const txt = reinterpret_cast(it->rinfo()->data()); flat_delta += it->rinfo()->pc() - prev_pc; if (txt[0] == ']') break; // End of nested comment // A new comment CollectCommentStatistics(it); // Skip code that was covered with previous comment prev_pc = it->rinfo()->pc(); } it->next(); } EnterComment(comment_txt, flat_delta); } // Collects code size statistics: // - by code kind // - by code comment void PagedSpace::CollectCodeStatistics() { HeapObjectIterator obj_it(this); while (obj_it.has_next()) { HeapObject* obj = obj_it.next(); if (obj->IsCode()) { Code* code = Code::cast(obj); code_kind_statistics[code->kind()] += code->Size(); RelocIterator it(code); int delta = 0; const byte* prev_pc = code->instruction_start(); while (!it.done()) { if (it.rinfo()->rmode() == RelocInfo::COMMENT) { delta += it.rinfo()->pc() - prev_pc; CollectCommentStatistics(&it); prev_pc = it.rinfo()->pc(); } it.next(); } ASSERT(code->instruction_start() <= prev_pc && prev_pc <= code->relocation_start()); delta += code->relocation_start() - prev_pc; EnterComment("NoComment", delta); } } } void OldSpace::ReportStatistics() { int pct = Available() * 100 / Capacity(); PrintF(" capacity: %d, waste: %d, available: %d, %%%d\n", Capacity(), Waste(), Available(), pct); // Report remembered set statistics. int rset_marked_pointers = 0; int rset_marked_arrays = 0; int rset_marked_array_elements = 0; int cross_gen_pointers = 0; int cross_gen_array_elements = 0; PageIterator page_it(this, PageIterator::PAGES_IN_USE); while (page_it.has_next()) { Page* p = page_it.next(); for (Address rset_addr = p->RSetStart(); rset_addr < p->RSetEnd(); rset_addr += kIntSize) { int rset = Memory::int_at(rset_addr); if (rset != 0) { // Bits were set int intoff = rset_addr - p->address(); int bitoff = 0; for (; bitoff < kBitsPerInt; ++bitoff) { if ((rset & (1 << bitoff)) != 0) { int bitpos = intoff*kBitsPerByte + bitoff; Address slot = p->OffsetToAddress(bitpos << kObjectAlignmentBits); Object** obj = reinterpret_cast(slot); if (*obj == Heap::raw_unchecked_fixed_array_map()) { rset_marked_arrays++; FixedArray* fa = FixedArray::cast(HeapObject::FromAddress(slot)); rset_marked_array_elements += fa->length(); // Manually inline FixedArray::IterateBody Address elm_start = slot + FixedArray::kHeaderSize; Address elm_stop = elm_start + fa->length() * kPointerSize; for (Address elm_addr = elm_start; elm_addr < elm_stop; elm_addr += kPointerSize) { // Filter non-heap-object pointers Object** elm_p = reinterpret_cast(elm_addr); if (Heap::InNewSpace(*elm_p)) cross_gen_array_elements++; } } else { rset_marked_pointers++; if (Heap::InNewSpace(*obj)) cross_gen_pointers++; } } } } } } pct = rset_marked_pointers == 0 ? 0 : cross_gen_pointers * 100 / rset_marked_pointers; PrintF(" rset-marked pointers %d, to-new-space %d (%%%d)\n", rset_marked_pointers, cross_gen_pointers, pct); PrintF(" rset_marked arrays %d, ", rset_marked_arrays); PrintF(" elements %d, ", rset_marked_array_elements); pct = rset_marked_array_elements == 0 ? 0 : cross_gen_array_elements * 100 / rset_marked_array_elements; PrintF(" pointers to new space %d (%%%d)\n", cross_gen_array_elements, pct); PrintF(" total rset-marked bits %d\n", (rset_marked_pointers + rset_marked_arrays)); pct = (rset_marked_pointers + rset_marked_array_elements) == 0 ? 0 : (cross_gen_pointers + cross_gen_array_elements) * 100 / (rset_marked_pointers + rset_marked_array_elements); PrintF(" total rset pointers %d, true cross generation ones %d (%%%d)\n", (rset_marked_pointers + rset_marked_array_elements), (cross_gen_pointers + cross_gen_array_elements), pct); ClearHistograms(); HeapObjectIterator obj_it(this); while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); } ReportHistogram(true); } // Dump the range of remembered set words between [start, end) corresponding // to the pointers starting at object_p. The allocation_top is an object // pointer which should not be read past. This is important for large object // pages, where some bits in the remembered set range do not correspond to // allocated addresses. static void PrintRSetRange(Address start, Address end, Object** object_p, Address allocation_top) { Address rset_address = start; // If the range starts on on odd numbered word (eg, for large object extra // remembered set ranges), print some spaces. if ((reinterpret_cast(start) / kIntSize) % 2 == 1) { PrintF(" "); } // Loop over all the words in the range. while (rset_address < end) { uint32_t rset_word = Memory::uint32_at(rset_address); int bit_position = 0; // Loop over all the bits in the word. while (bit_position < kBitsPerInt) { if (object_p == reinterpret_cast(allocation_top)) { // Print a bar at the allocation pointer. PrintF("|"); } else if (object_p > reinterpret_cast(allocation_top)) { // Do not dereference object_p past the allocation pointer. PrintF("#"); } else if ((rset_word & (1 << bit_position)) == 0) { // Print a dot for zero bits. PrintF("."); } else if (Heap::InNewSpace(*object_p)) { // Print an X for one bits for pointers to new space. PrintF("X"); } else { // Print a circle for one bits for pointers to old space. PrintF("o"); } // Print a space after every 8th bit except the last. if (bit_position % 8 == 7 && bit_position != (kBitsPerInt - 1)) { PrintF(" "); } // Advance to next bit. bit_position++; object_p++; } // Print a newline after every odd numbered word, otherwise a space. if ((reinterpret_cast(rset_address) / kIntSize) % 2 == 1) { PrintF("\n"); } else { PrintF(" "); } // Advance to next remembered set word. rset_address += kIntSize; } } void PagedSpace::DoPrintRSet(const char* space_name) { PageIterator it(this, PageIterator::PAGES_IN_USE); while (it.has_next()) { Page* p = it.next(); PrintF("%s page 0x%x:\n", space_name, p); PrintRSetRange(p->RSetStart(), p->RSetEnd(), reinterpret_cast(p->ObjectAreaStart()), p->AllocationTop()); PrintF("\n"); } } void OldSpace::PrintRSet() { DoPrintRSet("old"); } #endif // ----------------------------------------------------------------------------- // FixedSpace implementation void FixedSpace::PrepareForMarkCompact(bool will_compact) { if (will_compact) { // Reset relocation info. MCResetRelocationInfo(); // During a compacting collection, everything in the space is considered // 'available' (set by the call to MCResetRelocationInfo) and we will // rediscover live and wasted bytes during the collection. ASSERT(Available() == Capacity()); } else { // During a non-compacting collection, everything below the linear // allocation pointer except wasted top-of-page blocks is considered // allocated and we will rediscover available bytes during the // collection. accounting_stats_.AllocateBytes(free_list_.available()); } // Clear the free list before a full GC---it will be rebuilt afterward. free_list_.Reset(); } void FixedSpace::MCCommitRelocationInfo() { // Update fast allocation info. allocation_info_.top = mc_forwarding_info_.top; allocation_info_.limit = mc_forwarding_info_.limit; ASSERT(allocation_info_.VerifyPagedAllocation()); // The space is compacted and we haven't yet wasted any space. ASSERT(Waste() == 0); // Update allocation_top of each page in use and compute waste. int computed_size = 0; PageIterator it(this, PageIterator::PAGES_USED_BY_MC); while (it.has_next()) { Page* page = it.next(); Address page_top = page->AllocationTop(); computed_size += page_top - page->ObjectAreaStart(); if (it.has_next()) { accounting_stats_.WasteBytes(page->ObjectAreaEnd() - page_top); } } // Make sure the computed size - based on the used portion of the // pages in use - matches the size we adjust during allocation. ASSERT(computed_size == Size()); } // Slow case for normal allocation. Try in order: (1) allocate in the next // page in the space, (2) allocate off the space's free list, (3) expand the // space, (4) fail. HeapObject* FixedSpace::SlowAllocateRaw(int size_in_bytes) { ASSERT_EQ(object_size_in_bytes_, size_in_bytes); // Linear allocation in this space has failed. If there is another page // in the space, move to that page and allocate there. This allocation // should succeed. Page* current_page = TopPageOf(allocation_info_); if (current_page->next_page()->is_valid()) { return AllocateInNextPage(current_page, size_in_bytes); } // There is no next page in this space. Try free list allocation. // The fixed space free list implicitly assumes that all free blocks // are of the fixed size. if (size_in_bytes == object_size_in_bytes_) { Object* result = free_list_.Allocate(); if (!result->IsFailure()) { accounting_stats_.AllocateBytes(size_in_bytes); return HeapObject::cast(result); } } // Free list allocation failed and there is no next page. Fail if we have // hit the old generation size limit that should cause a garbage // collection. if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) { return NULL; } // Try to expand the space and allocate in the new next page. ASSERT(!current_page->next_page()->is_valid()); if (Expand(current_page)) { return AllocateInNextPage(current_page, size_in_bytes); } // Finally, fail. return NULL; } // Move to the next page (there is assumed to be one) and allocate there. // The top of page block is always wasted, because it is too small to hold a // map. HeapObject* FixedSpace::AllocateInNextPage(Page* current_page, int size_in_bytes) { ASSERT(current_page->next_page()->is_valid()); ASSERT(current_page->ObjectAreaEnd() - allocation_info_.top == page_extra_); ASSERT_EQ(object_size_in_bytes_, size_in_bytes); accounting_stats_.WasteBytes(page_extra_); SetAllocationInfo(&allocation_info_, current_page->next_page()); return AllocateLinearly(&allocation_info_, size_in_bytes); } #ifdef DEBUG void FixedSpace::ReportStatistics() { int pct = Available() * 100 / Capacity(); PrintF(" capacity: %d, waste: %d, available: %d, %%%d\n", Capacity(), Waste(), Available(), pct); // Report remembered set statistics. int rset_marked_pointers = 0; int cross_gen_pointers = 0; PageIterator page_it(this, PageIterator::PAGES_IN_USE); while (page_it.has_next()) { Page* p = page_it.next(); for (Address rset_addr = p->RSetStart(); rset_addr < p->RSetEnd(); rset_addr += kIntSize) { int rset = Memory::int_at(rset_addr); if (rset != 0) { // Bits were set int intoff = rset_addr - p->address(); int bitoff = 0; for (; bitoff < kBitsPerInt; ++bitoff) { if ((rset & (1 << bitoff)) != 0) { int bitpos = intoff*kBitsPerByte + bitoff; Address slot = p->OffsetToAddress(bitpos << kObjectAlignmentBits); Object** obj = reinterpret_cast(slot); rset_marked_pointers++; if (Heap::InNewSpace(*obj)) cross_gen_pointers++; } } } } } pct = rset_marked_pointers == 0 ? 0 : cross_gen_pointers * 100 / rset_marked_pointers; PrintF(" rset-marked pointers %d, to-new-space %d (%%%d)\n", rset_marked_pointers, cross_gen_pointers, pct); ClearHistograms(); HeapObjectIterator obj_it(this); while (obj_it.has_next()) { CollectHistogramInfo(obj_it.next()); } ReportHistogram(false); } void FixedSpace::PrintRSet() { DoPrintRSet(name_); } #endif // ----------------------------------------------------------------------------- // MapSpace implementation void MapSpace::PrepareForMarkCompact(bool will_compact) { // Call prepare of the super class. FixedSpace::PrepareForMarkCompact(will_compact); if (will_compact) { // Initialize map index entry. int page_count = 0; PageIterator it(this, PageIterator::ALL_PAGES); while (it.has_next()) { ASSERT_MAP_PAGE_INDEX(page_count); Page* p = it.next(); ASSERT(p->mc_page_index == page_count); page_addresses_[page_count++] = p->address(); } } } #ifdef DEBUG void MapSpace::VerifyObject(HeapObject* object) { // The object should be a map or a free-list node. ASSERT(object->IsMap() || object->IsByteArray()); } #endif // ----------------------------------------------------------------------------- // GlobalPropertyCellSpace implementation #ifdef DEBUG void CellSpace::VerifyObject(HeapObject* object) { // The object should be a global object property cell or a free-list node. ASSERT(object->IsJSGlobalPropertyCell() || object->map() == Heap::two_pointer_filler_map()); } #endif // ----------------------------------------------------------------------------- // LargeObjectIterator LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space) { current_ = space->first_chunk_; size_func_ = NULL; } LargeObjectIterator::LargeObjectIterator(LargeObjectSpace* space, HeapObjectCallback size_func) { current_ = space->first_chunk_; size_func_ = size_func; } HeapObject* LargeObjectIterator::next() { ASSERT(has_next()); HeapObject* object = current_->GetObject(); current_ = current_->next(); return object; } // ----------------------------------------------------------------------------- // LargeObjectChunk LargeObjectChunk* LargeObjectChunk::New(int size_in_bytes, size_t* chunk_size, Executability executable) { size_t requested = ChunkSizeFor(size_in_bytes); void* mem = MemoryAllocator::AllocateRawMemory(requested, chunk_size, executable); if (mem == NULL) return NULL; LOG(NewEvent("LargeObjectChunk", mem, *chunk_size)); if (*chunk_size < requested) { MemoryAllocator::FreeRawMemory(mem, *chunk_size); LOG(DeleteEvent("LargeObjectChunk", mem)); return NULL; } return reinterpret_cast(mem); } int LargeObjectChunk::ChunkSizeFor(int size_in_bytes) { int os_alignment = OS::AllocateAlignment(); if (os_alignment < Page::kPageSize) size_in_bytes += (Page::kPageSize - os_alignment); return size_in_bytes + Page::kObjectStartOffset; } // ----------------------------------------------------------------------------- // LargeObjectSpace LargeObjectSpace::LargeObjectSpace(AllocationSpace id) : Space(id, NOT_EXECUTABLE), // Managed on a per-allocation basis first_chunk_(NULL), size_(0), page_count_(0) {} bool LargeObjectSpace::Setup() { first_chunk_ = NULL; size_ = 0; page_count_ = 0; return true; } void LargeObjectSpace::TearDown() { while (first_chunk_ != NULL) { LargeObjectChunk* chunk = first_chunk_; first_chunk_ = first_chunk_->next(); LOG(DeleteEvent("LargeObjectChunk", chunk->address())); MemoryAllocator::FreeRawMemory(chunk->address(), chunk->size()); } size_ = 0; page_count_ = 0; } #ifdef ENABLE_HEAP_PROTECTION void LargeObjectSpace::Protect() { LargeObjectChunk* chunk = first_chunk_; while (chunk != NULL) { MemoryAllocator::Protect(chunk->address(), chunk->size()); chunk = chunk->next(); } } void LargeObjectSpace::Unprotect() { LargeObjectChunk* chunk = first_chunk_; while (chunk != NULL) { bool is_code = chunk->GetObject()->IsCode(); MemoryAllocator::Unprotect(chunk->address(), chunk->size(), is_code ? EXECUTABLE : NOT_EXECUTABLE); chunk = chunk->next(); } } #endif Object* LargeObjectSpace::AllocateRawInternal(int requested_size, int object_size, Executability executable) { ASSERT(0 < object_size && object_size <= requested_size); // Check if we want to force a GC before growing the old space further. // If so, fail the allocation. if (!Heap::always_allocate() && Heap::OldGenerationAllocationLimitReached()) { return Failure::RetryAfterGC(requested_size, identity()); } size_t chunk_size; LargeObjectChunk* chunk = LargeObjectChunk::New(requested_size, &chunk_size, executable); if (chunk == NULL) { return Failure::RetryAfterGC(requested_size, identity()); } size_ += chunk_size; page_count_++; chunk->set_next(first_chunk_); chunk->set_size(chunk_size); first_chunk_ = chunk; // Set the object address and size in the page header and clear its // remembered set. Page* page = Page::FromAddress(RoundUp(chunk->address(), Page::kPageSize)); Address object_address = page->ObjectAreaStart(); // Clear the low order bit of the second word in the page to flag it as a // large object page. If the chunk_size happened to be written there, its // low order bit should already be clear. ASSERT((chunk_size & 0x1) == 0); page->is_normal_page &= ~0x1; page->ClearRSet(); int extra_bytes = requested_size - object_size; if (extra_bytes > 0) { // The extra memory for the remembered set should be cleared. memset(object_address + object_size, 0, extra_bytes); } return HeapObject::FromAddress(object_address); } Object* LargeObjectSpace::AllocateRawCode(int size_in_bytes) { ASSERT(0 < size_in_bytes); return AllocateRawInternal(size_in_bytes, size_in_bytes, EXECUTABLE); } Object* LargeObjectSpace::AllocateRawFixedArray(int size_in_bytes) { ASSERT(0 < size_in_bytes); int extra_rset_bytes = ExtraRSetBytesFor(size_in_bytes); return AllocateRawInternal(size_in_bytes + extra_rset_bytes, size_in_bytes, NOT_EXECUTABLE); } Object* LargeObjectSpace::AllocateRaw(int size_in_bytes) { ASSERT(0 < size_in_bytes); return AllocateRawInternal(size_in_bytes, size_in_bytes, NOT_EXECUTABLE); } // GC support Object* LargeObjectSpace::FindObject(Address a) { for (LargeObjectChunk* chunk = first_chunk_; chunk != NULL; chunk = chunk->next()) { Address chunk_address = chunk->address(); if (chunk_address <= a && a < chunk_address + chunk->size()) { return chunk->GetObject(); } } return Failure::Exception(); } void LargeObjectSpace::ClearRSet() { ASSERT(Page::is_rset_in_use()); LargeObjectIterator it(this); while (it.has_next()) { HeapObject* object = it.next(); // We only have code, sequential strings, or fixed arrays in large // object space, and only fixed arrays need remembered set support. if (object->IsFixedArray()) { // Clear the normal remembered set region of the page; Page* page = Page::FromAddress(object->address()); page->ClearRSet(); // Clear the extra remembered set. int size = object->Size(); int extra_rset_bytes = ExtraRSetBytesFor(size); memset(object->address() + size, 0, extra_rset_bytes); } } } void LargeObjectSpace::IterateRSet(ObjectSlotCallback copy_object_func) { ASSERT(Page::is_rset_in_use()); static void* lo_rset_histogram = StatsTable::CreateHistogram( "V8.RSetLO", 0, // Keeping this histogram's buckets the same as the paged space histogram. Page::kObjectAreaSize / kPointerSize, 30); LargeObjectIterator it(this); while (it.has_next()) { // We only have code, sequential strings, or fixed arrays in large // object space, and only fixed arrays can possibly contain pointers to // the young generation. HeapObject* object = it.next(); if (object->IsFixedArray()) { // Iterate the normal page remembered set range. Page* page = Page::FromAddress(object->address()); Address object_end = object->address() + object->Size(); int count = Heap::IterateRSetRange(page->ObjectAreaStart(), Min(page->ObjectAreaEnd(), object_end), page->RSetStart(), copy_object_func); // Iterate the extra array elements. if (object_end > page->ObjectAreaEnd()) { count += Heap::IterateRSetRange(page->ObjectAreaEnd(), object_end, object_end, copy_object_func); } if (lo_rset_histogram != NULL) { StatsTable::AddHistogramSample(lo_rset_histogram, count); } } } } void LargeObjectSpace::FreeUnmarkedObjects() { LargeObjectChunk* previous = NULL; LargeObjectChunk* current = first_chunk_; while (current != NULL) { HeapObject* object = current->GetObject(); if (object->IsMarked()) { object->ClearMark(); MarkCompactCollector::tracer()->decrement_marked_count(); previous = current; current = current->next(); } else { Address chunk_address = current->address(); size_t chunk_size = current->size(); // Cut the chunk out from the chunk list. current = current->next(); if (previous == NULL) { first_chunk_ = current; } else { previous->set_next(current); } // Free the chunk. if (object->IsCode()) { LOG(CodeDeleteEvent(object->address())); } size_ -= chunk_size; page_count_--; MemoryAllocator::FreeRawMemory(chunk_address, chunk_size); LOG(DeleteEvent("LargeObjectChunk", chunk_address)); } } } bool LargeObjectSpace::Contains(HeapObject* object) { Address address = object->address(); Page* page = Page::FromAddress(address); SLOW_ASSERT(!page->IsLargeObjectPage() || !FindObject(address)->IsFailure()); return page->IsLargeObjectPage(); } #ifdef DEBUG // We do not assume that the large object iterator works, because it depends // on the invariants we are checking during verification. void LargeObjectSpace::Verify() { for (LargeObjectChunk* chunk = first_chunk_; chunk != NULL; chunk = chunk->next()) { // Each chunk contains an object that starts at the large object page's // object area start. HeapObject* object = chunk->GetObject(); Page* page = Page::FromAddress(object->address()); ASSERT(object->address() == page->ObjectAreaStart()); // The first word should be a map, and we expect all map pointers to be // in map space. Map* map = object->map(); ASSERT(map->IsMap()); ASSERT(Heap::map_space()->Contains(map)); // We have only code, sequential strings, fixed arrays, and byte arrays // in large object space. ASSERT(object->IsCode() || object->IsSeqString() || object->IsFixedArray() || object->IsByteArray()); // The object itself should look OK. object->Verify(); // Byte arrays and strings don't have interior pointers. if (object->IsCode()) { VerifyPointersVisitor code_visitor; Code::cast(object)->ConvertICTargetsFromAddressToObject(); object->IterateBody(map->instance_type(), object->Size(), &code_visitor); Code::cast(object)->ConvertICTargetsFromObjectToAddress(); } else if (object->IsFixedArray()) { // We loop over fixed arrays ourselves, rather then using the visitor, // because the visitor doesn't support the start/offset iteration // needed for IsRSetSet. FixedArray* array = FixedArray::cast(object); for (int j = 0; j < array->length(); j++) { Object* element = array->get(j); if (element->IsHeapObject()) { HeapObject* element_object = HeapObject::cast(element); ASSERT(Heap::Contains(element_object)); ASSERT(element_object->map()->IsMap()); if (Heap::InNewSpace(element_object)) { ASSERT(Page::IsRSetSet(object->address(), FixedArray::kHeaderSize + j * kPointerSize)); } } } } } } void LargeObjectSpace::Print() { LargeObjectIterator it(this); while (it.has_next()) { it.next()->Print(); } } void LargeObjectSpace::ReportStatistics() { PrintF(" size: %d\n", size_); int num_objects = 0; ClearHistograms(); LargeObjectIterator it(this); while (it.has_next()) { num_objects++; CollectHistogramInfo(it.next()); } PrintF(" number of objects %d\n", num_objects); if (num_objects > 0) ReportHistogram(false); } void LargeObjectSpace::CollectCodeStatistics() { LargeObjectIterator obj_it(this); while (obj_it.has_next()) { HeapObject* obj = obj_it.next(); if (obj->IsCode()) { Code* code = Code::cast(obj); code_kind_statistics[code->kind()] += code->Size(); } } } void LargeObjectSpace::PrintRSet() { LargeObjectIterator it(this); while (it.has_next()) { HeapObject* object = it.next(); if (object->IsFixedArray()) { Page* page = Page::FromAddress(object->address()); Address allocation_top = object->address() + object->Size(); PrintF("large page 0x%x:\n", page); PrintRSetRange(page->RSetStart(), page->RSetEnd(), reinterpret_cast(object->address()), allocation_top); int extra_array_bytes = object->Size() - Page::kObjectAreaSize; int extra_rset_bits = RoundUp(extra_array_bytes / kPointerSize, kBitsPerInt); PrintF("------------------------------------------------------------" "-----------\n"); PrintRSetRange(allocation_top, allocation_top + extra_rset_bits / kBitsPerByte, reinterpret_cast(object->address() + Page::kObjectAreaSize), allocation_top); PrintF("\n"); } } } #endif // DEBUG } } // namespace v8::internal