| /* |
| * Copyright (C) 2013 Google Inc. 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 "config.h" |
| #include "platform/heap/HeapPage.h" |
| |
| #include "platform/ScriptForbiddenScope.h" |
| #include "platform/Task.h" |
| #include "platform/TraceEvent.h" |
| #include "platform/heap/BlinkGCMemoryDumpProvider.h" |
| #include "platform/heap/CallbackStack.h" |
| #include "platform/heap/Heap.h" |
| #include "platform/heap/MarkingVisitor.h" |
| #include "platform/heap/PageMemory.h" |
| #include "platform/heap/PagePool.h" |
| #include "platform/heap/SafePoint.h" |
| #include "platform/heap/ThreadState.h" |
| #include "public/platform/Platform.h" |
| #include "public/platform/WebMemoryAllocatorDump.h" |
| #include "public/platform/WebProcessMemoryDump.h" |
| #include "wtf/Assertions.h" |
| #include "wtf/ContainerAnnotations.h" |
| #include "wtf/LeakAnnotations.h" |
| #include "wtf/MainThread.h" |
| #include "wtf/PageAllocator.h" |
| #include "wtf/Partitions.h" |
| #include "wtf/PassOwnPtr.h" |
| |
| #ifdef ANNOTATE_CONTIGUOUS_CONTAINER |
| // FIXME: have ContainerAnnotations.h define an ENABLE_-style name instead. |
| #define ENABLE_ASAN_CONTAINER_ANNOTATIONS 1 |
| |
| // When finalizing a non-inlined vector backing store/container, remove |
| // its contiguous container annotation. Required as it will not be destructed |
| // from its Vector. |
| #define ASAN_RETIRE_CONTAINER_ANNOTATION(object, objectSize) \ |
| do { \ |
| BasePage* page = pageFromObject(object); \ |
| ASSERT(page); \ |
| bool isContainer = ThreadState::isVectorHeapIndex(page->heap()->heapIndex()); \ |
| if (!isContainer && page->isLargeObjectPage()) \ |
| isContainer = static_cast<LargeObjectPage*>(page)->isVectorBackingPage(); \ |
| if (isContainer) \ |
| ANNOTATE_DELETE_BUFFER(object, objectSize, 0); \ |
| } while (0) |
| |
| // A vector backing store represented by a large object is marked |
| // so that when it is finalized, its ASan annotation will be |
| // correctly retired. |
| #define ASAN_MARK_LARGE_VECTOR_CONTAINER(heap, largeObject) \ |
| if (ThreadState::isVectorHeapIndex(heap->heapIndex())) { \ |
| BasePage* largePage = pageFromObject(largeObject); \ |
| ASSERT(largePage->isLargeObjectPage()); \ |
| static_cast<LargeObjectPage*>(largePage)->setIsVectorBackingPage(); \ |
| } |
| #else |
| #define ENABLE_ASAN_CONTAINER_ANNOTATIONS 0 |
| #define ASAN_RETIRE_CONTAINER_ANNOTATION(payload, payloadSize) |
| #define ASAN_MARK_LARGE_VECTOR_CONTAINER(heap, largeObject) |
| #endif |
| |
| namespace blink { |
| |
| #if ENABLE(ASSERT) |
| NO_SANITIZE_ADDRESS |
| void HeapObjectHeader::zapMagic() |
| { |
| ASSERT(checkHeader()); |
| m_magic = zappedMagic; |
| } |
| #endif |
| |
| void HeapObjectHeader::finalize(Address object, size_t objectSize) |
| { |
| const GCInfo* gcInfo = Heap::gcInfo(gcInfoIndex()); |
| if (gcInfo->hasFinalizer()) |
| gcInfo->m_finalize(object); |
| |
| ASAN_RETIRE_CONTAINER_ANNOTATION(object, objectSize); |
| } |
| |
| BaseHeap::BaseHeap(ThreadState* state, int index) |
| : m_firstPage(nullptr) |
| , m_firstUnsweptPage(nullptr) |
| , m_threadState(state) |
| , m_index(index) |
| { |
| } |
| |
| BaseHeap::~BaseHeap() |
| { |
| ASSERT(!m_firstPage); |
| ASSERT(!m_firstUnsweptPage); |
| } |
| |
| void BaseHeap::cleanupPages() |
| { |
| clearFreeLists(); |
| |
| ASSERT(!m_firstUnsweptPage); |
| // Add the BaseHeap's pages to the orphanedPagePool. |
| for (BasePage* page = m_firstPage; page; page = page->next()) { |
| Heap::decreaseAllocatedSpace(page->size()); |
| Heap::orphanedPagePool()->addOrphanedPage(heapIndex(), page); |
| } |
| m_firstPage = nullptr; |
| } |
| |
| void BaseHeap::takeSnapshot(const String& dumpBaseName, ThreadState::GCSnapshotInfo& info) |
| { |
| // |dumpBaseName| at this point is "blink_gc/thread_X/heaps/HeapName" |
| WebMemoryAllocatorDump* allocatorDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpBaseName); |
| size_t pageIndex = 0; |
| size_t heapTotalFreeSize = 0; |
| size_t heapTotalFreeCount = 0; |
| for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) { |
| size_t heapPageFreeSize = 0; |
| size_t heapPageFreeCount = 0; |
| page->takeSnapshot(dumpBaseName, pageIndex, info, &heapPageFreeSize, &heapPageFreeCount); |
| heapTotalFreeSize += heapPageFreeSize; |
| heapTotalFreeCount += heapPageFreeCount; |
| pageIndex++; |
| } |
| allocatorDump->addScalar("blink_page_count", "objects", pageIndex); |
| |
| // When taking a full dump (w/ freelist), both the /buckets and /pages |
| // report their free size but they are not meant to be added together. |
| // Therefore, here we override the free_size of the parent heap to be |
| // equal to the free_size of the sum of its heap pages. |
| allocatorDump->addScalar("free_size", "bytes", heapTotalFreeSize); |
| allocatorDump->addScalar("free_count", "objects", heapTotalFreeCount); |
| } |
| |
| #if ENABLE(ASSERT) |
| BasePage* BaseHeap::findPageFromAddress(Address address) |
| { |
| for (BasePage* page = m_firstPage; page; page = page->next()) { |
| if (page->contains(address)) |
| return page; |
| } |
| for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) { |
| if (page->contains(address)) |
| return page; |
| } |
| return nullptr; |
| } |
| #endif |
| |
| void BaseHeap::makeConsistentForGC() |
| { |
| clearFreeLists(); |
| ASSERT(isConsistentForGC()); |
| for (BasePage* page = m_firstPage; page; page = page->next()) |
| page->markAsUnswept(); |
| |
| // If a new GC is requested before this thread got around to sweep, |
| // ie. due to the thread doing a long running operation, we clear |
| // the mark bits and mark any of the dead objects as dead. The latter |
| // is used to ensure the next GC marking does not trace already dead |
| // objects. If we trace a dead object we could end up tracing into |
| // garbage or the middle of another object via the newly conservatively |
| // found object. |
| BasePage* previousPage = nullptr; |
| for (BasePage* page = m_firstUnsweptPage; page; previousPage = page, page = page->next()) { |
| page->makeConsistentForGC(); |
| ASSERT(!page->hasBeenSwept()); |
| } |
| if (previousPage) { |
| ASSERT(m_firstUnsweptPage); |
| previousPage->m_next = m_firstPage; |
| m_firstPage = m_firstUnsweptPage; |
| m_firstUnsweptPage = nullptr; |
| } |
| ASSERT(!m_firstUnsweptPage); |
| } |
| |
| void BaseHeap::makeConsistentForMutator() |
| { |
| clearFreeLists(); |
| ASSERT(isConsistentForGC()); |
| ASSERT(!m_firstPage); |
| |
| // Drop marks from marked objects and rebuild free lists in preparation for |
| // resuming the executions of mutators. |
| BasePage* previousPage = nullptr; |
| for (BasePage* page = m_firstUnsweptPage; page; previousPage = page, page = page->next()) { |
| page->makeConsistentForMutator(); |
| page->markAsSwept(); |
| } |
| if (previousPage) { |
| ASSERT(m_firstUnsweptPage); |
| previousPage->m_next = m_firstPage; |
| m_firstPage = m_firstUnsweptPage; |
| m_firstUnsweptPage = nullptr; |
| } |
| ASSERT(!m_firstUnsweptPage); |
| } |
| |
| size_t BaseHeap::objectPayloadSizeForTesting() |
| { |
| ASSERT(isConsistentForGC()); |
| ASSERT(!m_firstUnsweptPage); |
| |
| size_t objectPayloadSize = 0; |
| for (BasePage* page = m_firstPage; page; page = page->next()) |
| objectPayloadSize += page->objectPayloadSizeForTesting(); |
| return objectPayloadSize; |
| } |
| |
| void BaseHeap::prepareHeapForTermination() |
| { |
| ASSERT(!m_firstUnsweptPage); |
| for (BasePage* page = m_firstPage; page; page = page->next()) { |
| page->setTerminating(); |
| } |
| } |
| |
| void BaseHeap::prepareForSweep() |
| { |
| ASSERT(threadState()->isInGC()); |
| ASSERT(!m_firstUnsweptPage); |
| |
| // Move all pages to a list of unswept pages. |
| m_firstUnsweptPage = m_firstPage; |
| m_firstPage = nullptr; |
| } |
| |
| #if defined(ADDRESS_SANITIZER) |
| void BaseHeap::poisonHeap(BlinkGC::ObjectsToPoison objectsToPoison, BlinkGC::Poisoning poisoning) |
| { |
| // TODO(sof): support complete poisoning of all heaps. |
| ASSERT(objectsToPoison != BlinkGC::MarkedAndUnmarked || heapIndex() == BlinkGC::EagerSweepHeapIndex); |
| |
| // This method may either be called to poison (SetPoison) heap |
| // object payloads prior to sweeping, or it may be called at |
| // the completion of a sweep to unpoison (ClearPoison) the |
| // objects remaining in the heap. Those will all be live and unmarked. |
| // |
| // Poisoning may be limited to unmarked objects only, or apply to all. |
| if (poisoning == BlinkGC::SetPoison) { |
| for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) |
| page->poisonObjects(objectsToPoison, poisoning); |
| return; |
| } |
| // Support clearing of poisoning after sweeping has completed, |
| // in which case the pages of the live objects are reachable |
| // via m_firstPage. |
| ASSERT(!m_firstUnsweptPage); |
| for (BasePage* page = m_firstPage; page; page = page->next()) |
| page->poisonObjects(objectsToPoison, poisoning); |
| } |
| #endif |
| |
| Address BaseHeap::lazySweep(size_t allocationSize, size_t gcInfoIndex) |
| { |
| // If there are no pages to be swept, return immediately. |
| if (!m_firstUnsweptPage) |
| return nullptr; |
| |
| RELEASE_ASSERT(threadState()->isSweepingInProgress()); |
| |
| // lazySweepPages() can be called recursively if finalizers invoked in |
| // page->sweep() allocate memory and the allocation triggers |
| // lazySweepPages(). This check prevents the sweeping from being executed |
| // recursively. |
| if (threadState()->sweepForbidden()) |
| return nullptr; |
| |
| TRACE_EVENT0("blink_gc", "BaseHeap::lazySweepPages"); |
| ThreadState::SweepForbiddenScope scope(threadState()); |
| double startTime = WTF::currentTimeMS(); |
| |
| if (threadState()->isMainThread()) |
| ScriptForbiddenScope::enter(); |
| |
| Address result = lazySweepPages(allocationSize, gcInfoIndex); |
| |
| if (threadState()->isMainThread()) |
| ScriptForbiddenScope::exit(); |
| |
| threadState()->accumulateSweepingTime(WTF::currentTimeMS() - startTime); |
| Heap::reportMemoryUsageForTracing(); |
| |
| return result; |
| } |
| |
| void BaseHeap::sweepUnsweptPage() |
| { |
| BasePage* page = m_firstUnsweptPage; |
| if (page->isEmpty()) { |
| page->unlink(&m_firstUnsweptPage); |
| page->removeFromHeap(); |
| } else { |
| // Sweep a page and move the page from m_firstUnsweptPages to |
| // m_firstPages. |
| page->sweep(); |
| page->unlink(&m_firstUnsweptPage); |
| page->link(&m_firstPage); |
| page->markAsSwept(); |
| } |
| } |
| |
| bool BaseHeap::lazySweepWithDeadline(double deadlineSeconds) |
| { |
| // It might be heavy to call Platform::current()->monotonicallyIncreasingTimeSeconds() |
| // per page (i.e., 128 KB sweep or one LargeObject sweep), so we check |
| // the deadline per 10 pages. |
| static const int deadlineCheckInterval = 10; |
| |
| RELEASE_ASSERT(threadState()->isSweepingInProgress()); |
| ASSERT(threadState()->sweepForbidden()); |
| ASSERT(!threadState()->isMainThread() || ScriptForbiddenScope::isScriptForbidden()); |
| |
| int pageCount = 1; |
| while (m_firstUnsweptPage) { |
| sweepUnsweptPage(); |
| if (pageCount % deadlineCheckInterval == 0) { |
| if (deadlineSeconds <= Platform::current()->monotonicallyIncreasingTimeSeconds()) { |
| // Deadline has come. |
| Heap::reportMemoryUsageForTracing(); |
| return !m_firstUnsweptPage; |
| } |
| } |
| pageCount++; |
| } |
| Heap::reportMemoryUsageForTracing(); |
| return true; |
| } |
| |
| void BaseHeap::completeSweep() |
| { |
| RELEASE_ASSERT(threadState()->isSweepingInProgress()); |
| ASSERT(threadState()->sweepForbidden()); |
| ASSERT(!threadState()->isMainThread() || ScriptForbiddenScope::isScriptForbidden()); |
| |
| while (m_firstUnsweptPage) { |
| sweepUnsweptPage(); |
| } |
| Heap::reportMemoryUsageForTracing(); |
| } |
| |
| NormalPageHeap::NormalPageHeap(ThreadState* state, int index) |
| : BaseHeap(state, index) |
| , m_currentAllocationPoint(nullptr) |
| , m_remainingAllocationSize(0) |
| , m_lastRemainingAllocationSize(0) |
| , m_promptlyFreedSize(0) |
| { |
| clearFreeLists(); |
| } |
| |
| void NormalPageHeap::clearFreeLists() |
| { |
| setAllocationPoint(nullptr, 0); |
| m_freeList.clear(); |
| } |
| |
| #if ENABLE(ASSERT) |
| bool NormalPageHeap::isConsistentForGC() |
| { |
| // A thread heap is consistent for sweeping if none of the pages to be swept |
| // contain a freelist block or the current allocation point. |
| for (size_t i = 0; i < blinkPageSizeLog2; ++i) { |
| for (FreeListEntry* freeListEntry = m_freeList.m_freeLists[i]; freeListEntry; freeListEntry = freeListEntry->next()) { |
| if (pagesToBeSweptContains(freeListEntry->address())) |
| return false; |
| } |
| } |
| if (hasCurrentAllocationArea()) { |
| if (pagesToBeSweptContains(currentAllocationPoint())) |
| return false; |
| } |
| return true; |
| } |
| |
| bool NormalPageHeap::pagesToBeSweptContains(Address address) |
| { |
| for (BasePage* page = m_firstUnsweptPage; page; page = page->next()) { |
| if (page->contains(address)) |
| return true; |
| } |
| return false; |
| } |
| #endif |
| |
| void NormalPageHeap::takeFreelistSnapshot(const String& dumpName) |
| { |
| if (m_freeList.takeSnapshot(dumpName)) { |
| WebMemoryAllocatorDump* bucketsDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName + "/buckets"); |
| WebMemoryAllocatorDump* pagesDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName + "/pages"); |
| BlinkGCMemoryDumpProvider::instance()->currentProcessMemoryDump()->addOwnershipEdge(pagesDump->guid(), bucketsDump->guid()); |
| } |
| } |
| |
| void NormalPageHeap::allocatePage() |
| { |
| threadState()->shouldFlushHeapDoesNotContainCache(); |
| PageMemory* pageMemory = Heap::freePagePool()->takeFreePage(heapIndex()); |
| |
| if (!pageMemory) { |
| // Allocate a memory region for blinkPagesPerRegion pages that |
| // will each have the following layout. |
| // |
| // [ guard os page | ... payload ... | guard os page ] |
| // ^---{ aligned to blink page size } |
| PageMemoryRegion* region = PageMemoryRegion::allocateNormalPages(); |
| |
| // Setup the PageMemory object for each of the pages in the region. |
| for (size_t i = 0; i < blinkPagesPerRegion; ++i) { |
| PageMemory* memory = PageMemory::setupPageMemoryInRegion(region, i * blinkPageSize, blinkPagePayloadSize()); |
| // Take the first possible page ensuring that this thread actually |
| // gets a page and add the rest to the page pool. |
| if (!pageMemory) { |
| bool result = memory->commit(); |
| // If you hit the ASSERT, it will mean that you're hitting |
| // the limit of the number of mmapped regions OS can support |
| // (e.g., /proc/sys/vm/max_map_count in Linux). |
| RELEASE_ASSERT(result); |
| pageMemory = memory; |
| } else { |
| Heap::freePagePool()->addFreePage(heapIndex(), memory); |
| } |
| } |
| } |
| |
| NormalPage* page = new (pageMemory->writableStart()) NormalPage(pageMemory, this); |
| page->link(&m_firstPage); |
| |
| Heap::increaseAllocatedSpace(page->size()); |
| #if ENABLE(ASSERT) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER) |
| // Allow the following addToFreeList() to add the newly allocated memory |
| // to the free list. |
| ASAN_UNPOISON_MEMORY_REGION(page->payload(), page->payloadSize()); |
| Address address = page->payload(); |
| for (size_t i = 0; i < page->payloadSize(); i++) |
| address[i] = reuseAllowedZapValue; |
| ASAN_POISON_MEMORY_REGION(page->payload(), page->payloadSize()); |
| #endif |
| addToFreeList(page->payload(), page->payloadSize()); |
| } |
| |
| void NormalPageHeap::freePage(NormalPage* page) |
| { |
| Heap::decreaseAllocatedSpace(page->size()); |
| |
| if (page->terminating()) { |
| // The thread is shutting down and this page is being removed as a part |
| // of the thread local GC. In that case the object could be traced in |
| // the next global GC if there is a dangling pointer from a live thread |
| // heap to this dead thread heap. To guard against this, we put the |
| // page into the orphaned page pool and zap the page memory. This |
| // ensures that tracing the dangling pointer in the next global GC just |
| // crashes instead of causing use-after-frees. After the next global |
| // GC, the orphaned pages are removed. |
| Heap::orphanedPagePool()->addOrphanedPage(heapIndex(), page); |
| } else { |
| PageMemory* memory = page->storage(); |
| page->~NormalPage(); |
| Heap::freePagePool()->addFreePage(heapIndex(), memory); |
| } |
| } |
| |
| bool NormalPageHeap::coalesce() |
| { |
| // Don't coalesce heaps if there are not enough promptly freed entries |
| // to be coalesced. |
| // |
| // FIXME: This threshold is determined just to optimize blink_perf |
| // benchmarks. Coalescing is very sensitive to the threashold and |
| // we need further investigations on the coalescing scheme. |
| if (m_promptlyFreedSize < 1024 * 1024) |
| return false; |
| |
| if (threadState()->sweepForbidden()) |
| return false; |
| |
| ASSERT(!hasCurrentAllocationArea()); |
| TRACE_EVENT0("blink_gc", "BaseHeap::coalesce"); |
| |
| // Rebuild free lists. |
| m_freeList.clear(); |
| size_t freedSize = 0; |
| for (NormalPage* page = static_cast<NormalPage*>(m_firstPage); page; page = static_cast<NormalPage*>(page->next())) { |
| page->clearObjectStartBitMap(); |
| Address startOfGap = page->payload(); |
| for (Address headerAddress = startOfGap; headerAddress < page->payloadEnd(); ) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| size_t size = header->size(); |
| ASSERT(size > 0); |
| ASSERT(size < blinkPagePayloadSize()); |
| |
| if (header->isPromptlyFreed()) { |
| ASSERT(size >= sizeof(HeapObjectHeader)); |
| // Zero the memory in the free list header to maintain the |
| // invariant that memory on the free list is zero filled. |
| // The rest of the memory is already on the free list and is |
| // therefore already zero filled. |
| SET_MEMORY_INACCESSIBLE(headerAddress, sizeof(HeapObjectHeader)); |
| CHECK_MEMORY_INACCESSIBLE(headerAddress, size); |
| freedSize += size; |
| headerAddress += size; |
| continue; |
| } |
| if (header->isFree()) { |
| // Zero the memory in the free list header to maintain the |
| // invariant that memory on the free list is zero filled. |
| // The rest of the memory is already on the free list and is |
| // therefore already zero filled. |
| SET_MEMORY_INACCESSIBLE(headerAddress, size < sizeof(FreeListEntry) ? size : sizeof(FreeListEntry)); |
| CHECK_MEMORY_INACCESSIBLE(headerAddress, size); |
| headerAddress += size; |
| continue; |
| } |
| ASSERT(header->checkHeader()); |
| if (startOfGap != headerAddress) |
| addToFreeList(startOfGap, headerAddress - startOfGap); |
| |
| headerAddress += size; |
| startOfGap = headerAddress; |
| } |
| |
| if (startOfGap != page->payloadEnd()) |
| addToFreeList(startOfGap, page->payloadEnd() - startOfGap); |
| } |
| Heap::decreaseAllocatedObjectSize(freedSize); |
| ASSERT(m_promptlyFreedSize == freedSize); |
| m_promptlyFreedSize = 0; |
| return true; |
| } |
| |
| void NormalPageHeap::promptlyFreeObject(HeapObjectHeader* header) |
| { |
| ASSERT(!threadState()->sweepForbidden()); |
| ASSERT(header->checkHeader()); |
| Address address = reinterpret_cast<Address>(header); |
| Address payload = header->payload(); |
| size_t size = header->size(); |
| size_t payloadSize = header->payloadSize(); |
| ASSERT(size > 0); |
| ASSERT(pageFromObject(address) == findPageFromAddress(address)); |
| |
| { |
| ThreadState::SweepForbiddenScope forbiddenScope(threadState()); |
| header->finalize(payload, payloadSize); |
| if (address + size == m_currentAllocationPoint) { |
| m_currentAllocationPoint = address; |
| setRemainingAllocationSize(m_remainingAllocationSize + size); |
| SET_MEMORY_INACCESSIBLE(address, size); |
| return; |
| } |
| SET_MEMORY_INACCESSIBLE(payload, payloadSize); |
| header->markPromptlyFreed(); |
| } |
| |
| m_promptlyFreedSize += size; |
| } |
| |
| bool NormalPageHeap::expandObject(HeapObjectHeader* header, size_t newSize) |
| { |
| // It's possible that Vector requests a smaller expanded size because |
| // Vector::shrinkCapacity can set a capacity smaller than the actual payload |
| // size. |
| ASSERT(header->checkHeader()); |
| if (header->payloadSize() >= newSize) |
| return true; |
| size_t allocationSize = Heap::allocationSizeFromSize(newSize); |
| ASSERT(allocationSize > header->size()); |
| size_t expandSize = allocationSize - header->size(); |
| if (isObjectAllocatedAtAllocationPoint(header) && expandSize <= m_remainingAllocationSize) { |
| m_currentAllocationPoint += expandSize; |
| ASSERT(m_remainingAllocationSize >= expandSize); |
| setRemainingAllocationSize(m_remainingAllocationSize - expandSize); |
| // Unpoison the memory used for the object (payload). |
| SET_MEMORY_ACCESSIBLE(header->payloadEnd(), expandSize); |
| header->setSize(allocationSize); |
| ASSERT(findPageFromAddress(header->payloadEnd() - 1)); |
| return true; |
| } |
| return false; |
| } |
| |
| bool NormalPageHeap::shrinkObject(HeapObjectHeader* header, size_t newSize) |
| { |
| ASSERT(header->checkHeader()); |
| ASSERT(header->payloadSize() > newSize); |
| size_t allocationSize = Heap::allocationSizeFromSize(newSize); |
| ASSERT(header->size() > allocationSize); |
| size_t shrinkSize = header->size() - allocationSize; |
| if (isObjectAllocatedAtAllocationPoint(header)) { |
| m_currentAllocationPoint -= shrinkSize; |
| setRemainingAllocationSize(m_remainingAllocationSize + shrinkSize); |
| SET_MEMORY_INACCESSIBLE(m_currentAllocationPoint, shrinkSize); |
| header->setSize(allocationSize); |
| return true; |
| } |
| ASSERT(shrinkSize >= sizeof(HeapObjectHeader)); |
| ASSERT(header->gcInfoIndex() > 0); |
| Address shrinkAddress = header->payloadEnd() - shrinkSize; |
| HeapObjectHeader* freedHeader = new (NotNull, shrinkAddress) HeapObjectHeader(shrinkSize, header->gcInfoIndex()); |
| freedHeader->markPromptlyFreed(); |
| ASSERT(pageFromObject(reinterpret_cast<Address>(header)) == findPageFromAddress(reinterpret_cast<Address>(header))); |
| m_promptlyFreedSize += shrinkSize; |
| header->setSize(allocationSize); |
| SET_MEMORY_INACCESSIBLE(shrinkAddress + sizeof(HeapObjectHeader), shrinkSize - sizeof(HeapObjectHeader)); |
| return false; |
| } |
| |
| Address NormalPageHeap::lazySweepPages(size_t allocationSize, size_t gcInfoIndex) |
| { |
| ASSERT(!hasCurrentAllocationArea()); |
| Address result = nullptr; |
| while (m_firstUnsweptPage) { |
| BasePage* page = m_firstUnsweptPage; |
| if (page->isEmpty()) { |
| page->unlink(&m_firstUnsweptPage); |
| page->removeFromHeap(); |
| } else { |
| // Sweep a page and move the page from m_firstUnsweptPages to |
| // m_firstPages. |
| page->sweep(); |
| page->unlink(&m_firstUnsweptPage); |
| page->link(&m_firstPage); |
| page->markAsSwept(); |
| |
| // For NormalPage, stop lazy sweeping once we find a slot to |
| // allocate a new object. |
| result = allocateFromFreeList(allocationSize, gcInfoIndex); |
| if (result) |
| break; |
| } |
| } |
| return result; |
| } |
| |
| void NormalPageHeap::setRemainingAllocationSize(size_t newRemainingAllocationSize) |
| { |
| m_remainingAllocationSize = newRemainingAllocationSize; |
| |
| // Sync recorded allocated-object size: |
| // - if previous alloc checkpoint is larger, allocation size has increased. |
| // - if smaller, a net reduction in size since last call to updateRemainingAllocationSize(). |
| if (m_lastRemainingAllocationSize > m_remainingAllocationSize) |
| Heap::increaseAllocatedObjectSize(m_lastRemainingAllocationSize - m_remainingAllocationSize); |
| else if (m_lastRemainingAllocationSize != m_remainingAllocationSize) |
| Heap::decreaseAllocatedObjectSize(m_remainingAllocationSize - m_lastRemainingAllocationSize); |
| m_lastRemainingAllocationSize = m_remainingAllocationSize; |
| } |
| |
| void NormalPageHeap::updateRemainingAllocationSize() |
| { |
| if (m_lastRemainingAllocationSize > remainingAllocationSize()) { |
| Heap::increaseAllocatedObjectSize(m_lastRemainingAllocationSize - remainingAllocationSize()); |
| m_lastRemainingAllocationSize = remainingAllocationSize(); |
| } |
| ASSERT(m_lastRemainingAllocationSize == remainingAllocationSize()); |
| } |
| |
| void NormalPageHeap::setAllocationPoint(Address point, size_t size) |
| { |
| #if ENABLE(ASSERT) |
| if (point) { |
| ASSERT(size); |
| BasePage* page = pageFromObject(point); |
| ASSERT(!page->isLargeObjectPage()); |
| ASSERT(size <= static_cast<NormalPage*>(page)->payloadSize()); |
| } |
| #endif |
| if (hasCurrentAllocationArea()) { |
| addToFreeList(currentAllocationPoint(), remainingAllocationSize()); |
| } |
| updateRemainingAllocationSize(); |
| m_currentAllocationPoint = point; |
| m_lastRemainingAllocationSize = m_remainingAllocationSize = size; |
| } |
| |
| Address NormalPageHeap::outOfLineAllocate(size_t allocationSize, size_t gcInfoIndex) |
| { |
| ASSERT(allocationSize > remainingAllocationSize()); |
| ASSERT(allocationSize >= allocationGranularity); |
| |
| // 1. If this allocation is big enough, allocate a large object. |
| if (allocationSize >= largeObjectSizeThreshold) { |
| // TODO(sof): support eagerly finalized large objects, if ever needed. |
| RELEASE_ASSERT(heapIndex() != BlinkGC::EagerSweepHeapIndex); |
| LargeObjectHeap* largeObjectHeap = static_cast<LargeObjectHeap*>(threadState()->heap(BlinkGC::LargeObjectHeapIndex)); |
| Address largeObject = largeObjectHeap->allocateLargeObjectPage(allocationSize, gcInfoIndex); |
| ASAN_MARK_LARGE_VECTOR_CONTAINER(this, largeObject); |
| return largeObject; |
| } |
| |
| // 2. Try to allocate from a free list. |
| updateRemainingAllocationSize(); |
| Address result = allocateFromFreeList(allocationSize, gcInfoIndex); |
| if (result) |
| return result; |
| |
| // 3. Reset the allocation point. |
| setAllocationPoint(nullptr, 0); |
| |
| // 4. Lazily sweep pages of this heap until we find a freed area for |
| // this allocation or we finish sweeping all pages of this heap. |
| result = lazySweep(allocationSize, gcInfoIndex); |
| if (result) |
| return result; |
| |
| // 5. Coalesce promptly freed areas and then try to allocate from a free |
| // list. |
| if (coalesce()) { |
| result = allocateFromFreeList(allocationSize, gcInfoIndex); |
| if (result) |
| return result; |
| } |
| |
| // 6. Complete sweeping. |
| threadState()->completeSweep(); |
| |
| // 7. Check if we should trigger a GC. |
| threadState()->scheduleGCIfNeeded(); |
| |
| // 8. Add a new page to this heap. |
| allocatePage(); |
| |
| // 9. Try to allocate from a free list. This allocation must succeed. |
| result = allocateFromFreeList(allocationSize, gcInfoIndex); |
| RELEASE_ASSERT(result); |
| return result; |
| } |
| |
| Address NormalPageHeap::allocateFromFreeList(size_t allocationSize, size_t gcInfoIndex) |
| { |
| // Try reusing a block from the largest bin. The underlying reasoning |
| // being that we want to amortize this slow allocation call by carving |
| // off as a large a free block as possible in one go; a block that will |
| // service this block and let following allocations be serviced quickly |
| // by bump allocation. |
| size_t bucketSize = 1 << m_freeList.m_biggestFreeListIndex; |
| int index = m_freeList.m_biggestFreeListIndex; |
| for (; index > 0; --index, bucketSize >>= 1) { |
| FreeListEntry* entry = m_freeList.m_freeLists[index]; |
| if (allocationSize > bucketSize) { |
| // Final bucket candidate; check initial entry if it is able |
| // to service this allocation. Do not perform a linear scan, |
| // as it is considered too costly. |
| if (!entry || entry->size() < allocationSize) |
| break; |
| } |
| if (entry) { |
| entry->unlink(&m_freeList.m_freeLists[index]); |
| setAllocationPoint(entry->address(), entry->size()); |
| ASSERT(hasCurrentAllocationArea()); |
| ASSERT(remainingAllocationSize() >= allocationSize); |
| m_freeList.m_biggestFreeListIndex = index; |
| return allocateObject(allocationSize, gcInfoIndex); |
| } |
| } |
| m_freeList.m_biggestFreeListIndex = index; |
| return nullptr; |
| } |
| |
| LargeObjectHeap::LargeObjectHeap(ThreadState* state, int index) |
| : BaseHeap(state, index) |
| { |
| } |
| |
| Address LargeObjectHeap::allocateLargeObjectPage(size_t allocationSize, size_t gcInfoIndex) |
| { |
| // Caller already added space for object header and rounded up to allocation |
| // alignment |
| ASSERT(!(allocationSize & allocationMask)); |
| |
| // 1. Try to sweep large objects more than allocationSize bytes |
| // before allocating a new large object. |
| Address result = lazySweep(allocationSize, gcInfoIndex); |
| if (result) |
| return result; |
| |
| // 2. If we have failed in sweeping allocationSize bytes, |
| // we complete sweeping before allocating this large object. |
| threadState()->completeSweep(); |
| |
| // 3. Check if we should trigger a GC. |
| threadState()->scheduleGCIfNeeded(); |
| |
| return doAllocateLargeObjectPage(allocationSize, gcInfoIndex); |
| } |
| |
| Address LargeObjectHeap::doAllocateLargeObjectPage(size_t allocationSize, size_t gcInfoIndex) |
| { |
| size_t largeObjectSize = LargeObjectPage::pageHeaderSize() + allocationSize; |
| // If ASan is supported we add allocationGranularity bytes to the allocated |
| // space and poison that to detect overflows |
| #if defined(ADDRESS_SANITIZER) |
| largeObjectSize += allocationGranularity; |
| #endif |
| |
| threadState()->shouldFlushHeapDoesNotContainCache(); |
| PageMemory* pageMemory = PageMemory::allocate(largeObjectSize); |
| Address largeObjectAddress = pageMemory->writableStart(); |
| Address headerAddress = largeObjectAddress + LargeObjectPage::pageHeaderSize(); |
| #if ENABLE(ASSERT) |
| // Verify that the allocated PageMemory is expectedly zeroed. |
| for (size_t i = 0; i < largeObjectSize; ++i) |
| ASSERT(!largeObjectAddress[i]); |
| #endif |
| ASSERT(gcInfoIndex > 0); |
| HeapObjectHeader* header = new (NotNull, headerAddress) HeapObjectHeader(largeObjectSizeInHeader, gcInfoIndex); |
| Address result = headerAddress + sizeof(*header); |
| ASSERT(!(reinterpret_cast<uintptr_t>(result) & allocationMask)); |
| LargeObjectPage* largeObject = new (largeObjectAddress) LargeObjectPage(pageMemory, this, allocationSize); |
| ASSERT(header->checkHeader()); |
| |
| // Poison the object header and allocationGranularity bytes after the object |
| ASAN_POISON_MEMORY_REGION(header, sizeof(*header)); |
| ASAN_POISON_MEMORY_REGION(largeObject->address() + largeObject->size(), allocationGranularity); |
| |
| largeObject->link(&m_firstPage); |
| |
| Heap::increaseAllocatedSpace(largeObject->size()); |
| Heap::increaseAllocatedObjectSize(largeObject->size()); |
| return result; |
| } |
| |
| void LargeObjectHeap::freeLargeObjectPage(LargeObjectPage* object) |
| { |
| ASAN_UNPOISON_MEMORY_REGION(object->payload(), object->payloadSize()); |
| object->heapObjectHeader()->finalize(object->payload(), object->payloadSize()); |
| Heap::decreaseAllocatedSpace(object->size()); |
| |
| // Unpoison the object header and allocationGranularity bytes after the |
| // object before freeing. |
| ASAN_UNPOISON_MEMORY_REGION(object->heapObjectHeader(), sizeof(HeapObjectHeader)); |
| ASAN_UNPOISON_MEMORY_REGION(object->address() + object->size(), allocationGranularity); |
| |
| if (object->terminating()) { |
| ASSERT(ThreadState::current()->isTerminating()); |
| // The thread is shutting down and this page is being removed as a part |
| // of the thread local GC. In that case the object could be traced in |
| // the next global GC if there is a dangling pointer from a live thread |
| // heap to this dead thread heap. To guard against this, we put the |
| // page into the orphaned page pool and zap the page memory. This |
| // ensures that tracing the dangling pointer in the next global GC just |
| // crashes instead of causing use-after-frees. After the next global |
| // GC, the orphaned pages are removed. |
| Heap::orphanedPagePool()->addOrphanedPage(heapIndex(), object); |
| } else { |
| ASSERT(!ThreadState::current()->isTerminating()); |
| PageMemory* memory = object->storage(); |
| object->~LargeObjectPage(); |
| delete memory; |
| } |
| } |
| |
| Address LargeObjectHeap::lazySweepPages(size_t allocationSize, size_t gcInfoIndex) |
| { |
| Address result = nullptr; |
| size_t sweptSize = 0; |
| while (m_firstUnsweptPage) { |
| BasePage* page = m_firstUnsweptPage; |
| if (page->isEmpty()) { |
| sweptSize += static_cast<LargeObjectPage*>(page)->payloadSize() + sizeof(HeapObjectHeader); |
| page->unlink(&m_firstUnsweptPage); |
| page->removeFromHeap(); |
| // For LargeObjectPage, stop lazy sweeping once we have swept |
| // more than allocationSize bytes. |
| if (sweptSize >= allocationSize) { |
| result = doAllocateLargeObjectPage(allocationSize, gcInfoIndex); |
| ASSERT(result); |
| break; |
| } |
| } else { |
| // Sweep a page and move the page from m_firstUnsweptPages to |
| // m_firstPages. |
| page->sweep(); |
| page->unlink(&m_firstUnsweptPage); |
| page->link(&m_firstPage); |
| page->markAsSwept(); |
| } |
| } |
| return result; |
| } |
| |
| FreeList::FreeList() |
| : m_biggestFreeListIndex(0) |
| { |
| } |
| |
| void FreeList::addToFreeList(Address address, size_t size) |
| { |
| ASSERT(size < blinkPagePayloadSize()); |
| // The free list entries are only pointer aligned (but when we allocate |
| // from them we are 8 byte aligned due to the header size). |
| ASSERT(!((reinterpret_cast<uintptr_t>(address) + sizeof(HeapObjectHeader)) & allocationMask)); |
| ASSERT(!(size & allocationMask)); |
| ASAN_UNPOISON_MEMORY_REGION(address, size); |
| FreeListEntry* entry; |
| if (size < sizeof(*entry)) { |
| // Create a dummy header with only a size and freelist bit set. |
| ASSERT(size >= sizeof(HeapObjectHeader)); |
| // Free list encode the size to mark the lost memory as freelist memory. |
| new (NotNull, address) HeapObjectHeader(size, gcInfoIndexForFreeListHeader); |
| |
| ASAN_POISON_MEMORY_REGION(address, size); |
| // This memory gets lost. Sweeping can reclaim it. |
| return; |
| } |
| entry = new (NotNull, address) FreeListEntry(size); |
| |
| #if ENABLE(ASSERT) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER) |
| // The following logic delays reusing free lists for (at least) one GC |
| // cycle or coalescing. This is helpful to detect use-after-free errors |
| // that could be caused by lazy sweeping etc. |
| size_t allowedCount = 0; |
| size_t forbiddenCount = 0; |
| for (size_t i = sizeof(FreeListEntry); i < size; i++) { |
| if (address[i] == reuseAllowedZapValue) { |
| allowedCount++; |
| } else if (address[i] == reuseForbiddenZapValue) { |
| forbiddenCount++; |
| } else { |
| // TODO(haraken): Remove these assertions once bug 537922 is fixed. |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(&address[i]); |
| ASSERT(header->checkHeader()); |
| if (header->isPromptlyFreed()) |
| ASSERT_NOT_REACHED(); |
| else if (header->isFree()) |
| ASSERT_NOT_REACHED(); |
| else if (header->isDead()) |
| ASSERT_NOT_REACHED(); |
| else if (header->isMarked()) |
| ASSERT_NOT_REACHED(); |
| ASSERT_NOT_REACHED(); |
| } |
| } |
| size_t entryCount = size - sizeof(FreeListEntry); |
| if (forbiddenCount == entryCount) { |
| // If all values in the memory region are reuseForbiddenZapValue, |
| // we flip them to reuseAllowedZapValue. This allows the next |
| // addToFreeList() to add the memory region to the free list |
| // (unless someone concatenates the memory region with another memory |
| // region that contains reuseForbiddenZapValue.) |
| for (size_t i = sizeof(FreeListEntry); i < size; i++) |
| address[i] = reuseAllowedZapValue; |
| ASAN_POISON_MEMORY_REGION(address, size); |
| // Don't add the memory region to the free list in this addToFreeList(). |
| return; |
| } |
| if (allowedCount != entryCount) { |
| // If the memory region mixes reuseForbiddenZapValue and |
| // reuseAllowedZapValue, we (conservatively) flip all the values |
| // to reuseForbiddenZapValue. These values will be changed to |
| // reuseAllowedZapValue in the next addToFreeList(). |
| for (size_t i = sizeof(FreeListEntry); i < size; i++) |
| address[i] = reuseForbiddenZapValue; |
| ASAN_POISON_MEMORY_REGION(address, size); |
| // Don't add the memory region to the free list in this addToFreeList(). |
| return; |
| } |
| // We reach here only when all the values in the memory region are |
| // reuseAllowedZapValue. In this case, we are allowed to add the memory |
| // region to the free list and reuse it for another object. |
| #endif |
| ASAN_POISON_MEMORY_REGION(address, size); |
| |
| int index = bucketIndexForSize(size); |
| entry->link(&m_freeLists[index]); |
| if (index > m_biggestFreeListIndex) |
| m_biggestFreeListIndex = index; |
| } |
| |
| #if ENABLE(ASSERT) || defined(LEAK_SANITIZER) || defined(ADDRESS_SANITIZER) || defined(MEMORY_SANITIZER) |
| NO_SANITIZE_ADDRESS |
| NO_SANITIZE_MEMORY |
| void NEVER_INLINE FreeList::zapFreedMemory(Address address, size_t size) |
| { |
| for (size_t i = 0; i < size; i++) { |
| // See the comment in addToFreeList(). |
| if (address[i] != reuseAllowedZapValue) |
| address[i] = reuseForbiddenZapValue; |
| } |
| } |
| |
| void NEVER_INLINE FreeList::checkFreedMemoryIsZapped(Address address, size_t size) |
| { |
| for (size_t i = 0; i < size; i++) { |
| ASSERT(address[i] == reuseAllowedZapValue || address[i] == reuseForbiddenZapValue); |
| } |
| } |
| #endif |
| |
| void FreeList::clear() |
| { |
| m_biggestFreeListIndex = 0; |
| for (size_t i = 0; i < blinkPageSizeLog2; ++i) |
| m_freeLists[i] = nullptr; |
| } |
| |
| int FreeList::bucketIndexForSize(size_t size) |
| { |
| ASSERT(size > 0); |
| int index = -1; |
| while (size) { |
| size >>= 1; |
| index++; |
| } |
| return index; |
| } |
| |
| bool FreeList::takeSnapshot(const String& dumpBaseName) |
| { |
| bool didDumpBucketStats = false; |
| for (size_t i = 0; i < blinkPageSizeLog2; ++i) { |
| size_t entryCount = 0; |
| size_t freeSize = 0; |
| for (FreeListEntry* entry = m_freeLists[i]; entry; entry = entry->next()) { |
| ++entryCount; |
| freeSize += entry->size(); |
| } |
| |
| String dumpName = dumpBaseName + String::format("/buckets/bucket_%lu", static_cast<unsigned long>(1 << i)); |
| WebMemoryAllocatorDump* bucketDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName); |
| bucketDump->addScalar("free_count", "objects", entryCount); |
| bucketDump->addScalar("free_size", "bytes", freeSize); |
| didDumpBucketStats = true; |
| } |
| return didDumpBucketStats; |
| } |
| |
| BasePage::BasePage(PageMemory* storage, BaseHeap* heap) |
| : m_storage(storage) |
| , m_heap(heap) |
| , m_next(nullptr) |
| , m_terminating(false) |
| , m_swept(true) |
| { |
| ASSERT(isPageHeaderAddress(reinterpret_cast<Address>(this))); |
| } |
| |
| void BasePage::markOrphaned() |
| { |
| m_heap = nullptr; |
| m_terminating = false; |
| // Since we zap the page payload for orphaned pages we need to mark it as |
| // unused so a conservative pointer won't interpret the object headers. |
| storage()->markUnused(); |
| } |
| |
| NormalPage::NormalPage(PageMemory* storage, BaseHeap* heap) |
| : BasePage(storage, heap) |
| { |
| m_objectStartBitMapComputed = false; |
| ASSERT(isPageHeaderAddress(reinterpret_cast<Address>(this))); |
| } |
| |
| size_t NormalPage::objectPayloadSizeForTesting() |
| { |
| size_t objectPayloadSize = 0; |
| Address headerAddress = payload(); |
| markAsSwept(); |
| ASSERT(headerAddress != payloadEnd()); |
| do { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| if (!header->isFree()) { |
| ASSERT(header->checkHeader()); |
| objectPayloadSize += header->payloadSize(); |
| } |
| ASSERT(header->size() < blinkPagePayloadSize()); |
| headerAddress += header->size(); |
| ASSERT(headerAddress <= payloadEnd()); |
| } while (headerAddress < payloadEnd()); |
| return objectPayloadSize; |
| } |
| |
| bool NormalPage::isEmpty() |
| { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(payload()); |
| return header->isFree() && header->size() == payloadSize(); |
| } |
| |
| void NormalPage::removeFromHeap() |
| { |
| heapForNormalPage()->freePage(this); |
| } |
| |
| void NormalPage::sweep() |
| { |
| clearObjectStartBitMap(); |
| |
| size_t markedObjectSize = 0; |
| Address startOfGap = payload(); |
| for (Address headerAddress = startOfGap; headerAddress < payloadEnd(); ) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| ASSERT(header->size() > 0); |
| ASSERT(header->size() < blinkPagePayloadSize()); |
| |
| if (header->isPromptlyFreed()) |
| heapForNormalPage()->decreasePromptlyFreedSize(header->size()); |
| if (header->isFree()) { |
| size_t size = header->size(); |
| // Zero the memory in the free list header to maintain the |
| // invariant that memory on the free list is zero filled. |
| // The rest of the memory is already on the free list and is |
| // therefore already zero filled. |
| SET_MEMORY_INACCESSIBLE(headerAddress, size < sizeof(FreeListEntry) ? size : sizeof(FreeListEntry)); |
| CHECK_MEMORY_INACCESSIBLE(headerAddress, size); |
| headerAddress += size; |
| continue; |
| } |
| ASSERT(header->checkHeader()); |
| |
| if (!header->isMarked()) { |
| size_t size = header->size(); |
| // This is a fast version of header->payloadSize(). |
| size_t payloadSize = size - sizeof(HeapObjectHeader); |
| Address payload = header->payload(); |
| // For ASan, unpoison the object before calling the finalizer. The |
| // finalized object will be zero-filled and poison'ed afterwards. |
| // Given all other unmarked objects are poisoned, ASan will detect |
| // an error if the finalizer touches any other on-heap object that |
| // die at the same GC cycle. |
| ASAN_UNPOISON_MEMORY_REGION(payload, payloadSize); |
| header->finalize(payload, payloadSize); |
| // This memory will be added to the freelist. Maintain the invariant |
| // that memory on the freelist is zero filled. |
| SET_MEMORY_INACCESSIBLE(headerAddress, size); |
| headerAddress += size; |
| continue; |
| } |
| if (startOfGap != headerAddress) |
| heapForNormalPage()->addToFreeList(startOfGap, headerAddress - startOfGap); |
| header->unmark(); |
| headerAddress += header->size(); |
| markedObjectSize += header->size(); |
| startOfGap = headerAddress; |
| } |
| if (startOfGap != payloadEnd()) |
| heapForNormalPage()->addToFreeList(startOfGap, payloadEnd() - startOfGap); |
| |
| if (markedObjectSize) |
| Heap::increaseMarkedObjectSize(markedObjectSize); |
| } |
| |
| void NormalPage::makeConsistentForGC() |
| { |
| size_t markedObjectSize = 0; |
| for (Address headerAddress = payload(); headerAddress < payloadEnd();) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| ASSERT(header->size() < blinkPagePayloadSize()); |
| // Check if a free list entry first since we cannot call |
| // isMarked on a free list entry. |
| if (header->isFree()) { |
| headerAddress += header->size(); |
| continue; |
| } |
| ASSERT(header->checkHeader()); |
| if (header->isMarked()) { |
| header->unmark(); |
| markedObjectSize += header->size(); |
| } else { |
| header->markDead(); |
| } |
| headerAddress += header->size(); |
| } |
| if (markedObjectSize) |
| Heap::increaseMarkedObjectSize(markedObjectSize); |
| } |
| |
| void NormalPage::makeConsistentForMutator() |
| { |
| Address startOfGap = payload(); |
| for (Address headerAddress = payload(); headerAddress < payloadEnd();) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| size_t size = header->size(); |
| ASSERT(size < blinkPagePayloadSize()); |
| if (header->isPromptlyFreed()) |
| heapForNormalPage()->decreasePromptlyFreedSize(size); |
| if (header->isFree()) { |
| // Zero the memory in the free list header to maintain the |
| // invariant that memory on the free list is zero filled. |
| // The rest of the memory is already on the free list and is |
| // therefore already zero filled. |
| SET_MEMORY_INACCESSIBLE(headerAddress, size < sizeof(FreeListEntry) ? size : sizeof(FreeListEntry)); |
| CHECK_MEMORY_INACCESSIBLE(headerAddress, size); |
| headerAddress += size; |
| continue; |
| } |
| ASSERT(header->checkHeader()); |
| |
| if (startOfGap != headerAddress) |
| heapForNormalPage()->addToFreeList(startOfGap, headerAddress - startOfGap); |
| if (header->isMarked()) |
| header->unmark(); |
| headerAddress += size; |
| startOfGap = headerAddress; |
| ASSERT(headerAddress <= payloadEnd()); |
| } |
| if (startOfGap != payloadEnd()) |
| heapForNormalPage()->addToFreeList(startOfGap, payloadEnd() - startOfGap); |
| } |
| |
| #if defined(ADDRESS_SANITIZER) |
| void NormalPage::poisonObjects(BlinkGC::ObjectsToPoison objectsToPoison, BlinkGC::Poisoning poisoning) |
| { |
| for (Address headerAddress = payload(); headerAddress < payloadEnd();) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| ASSERT(header->size() < blinkPagePayloadSize()); |
| // Check if a free list entry first since we cannot call |
| // isMarked on a free list entry. |
| if (header->isFree()) { |
| headerAddress += header->size(); |
| continue; |
| } |
| ASSERT(header->checkHeader()); |
| if (objectsToPoison == BlinkGC::MarkedAndUnmarked || !header->isMarked()) { |
| if (poisoning == BlinkGC::SetPoison) |
| ASAN_POISON_MEMORY_REGION(header->payload(), header->payloadSize()); |
| else |
| ASAN_UNPOISON_MEMORY_REGION(header->payload(), header->payloadSize()); |
| } |
| headerAddress += header->size(); |
| } |
| } |
| #endif |
| |
| void NormalPage::populateObjectStartBitMap() |
| { |
| memset(&m_objectStartBitMap, 0, objectStartBitMapSize); |
| Address start = payload(); |
| for (Address headerAddress = start; headerAddress < payloadEnd();) { |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| size_t objectOffset = headerAddress - start; |
| ASSERT(!(objectOffset & allocationMask)); |
| size_t objectStartNumber = objectOffset / allocationGranularity; |
| size_t mapIndex = objectStartNumber / 8; |
| ASSERT(mapIndex < objectStartBitMapSize); |
| m_objectStartBitMap[mapIndex] |= (1 << (objectStartNumber & 7)); |
| headerAddress += header->size(); |
| ASSERT(headerAddress <= payloadEnd()); |
| } |
| m_objectStartBitMapComputed = true; |
| } |
| |
| void NormalPage::clearObjectStartBitMap() |
| { |
| m_objectStartBitMapComputed = false; |
| } |
| |
| static int numberOfLeadingZeroes(uint8_t byte) |
| { |
| if (!byte) |
| return 8; |
| int result = 0; |
| if (byte <= 0x0F) { |
| result += 4; |
| byte = byte << 4; |
| } |
| if (byte <= 0x3F) { |
| result += 2; |
| byte = byte << 2; |
| } |
| if (byte <= 0x7F) |
| result++; |
| return result; |
| } |
| |
| HeapObjectHeader* NormalPage::findHeaderFromAddress(Address address) |
| { |
| if (address < payload()) |
| return nullptr; |
| if (!isObjectStartBitMapComputed()) |
| populateObjectStartBitMap(); |
| size_t objectOffset = address - payload(); |
| size_t objectStartNumber = objectOffset / allocationGranularity; |
| size_t mapIndex = objectStartNumber / 8; |
| ASSERT(mapIndex < objectStartBitMapSize); |
| size_t bit = objectStartNumber & 7; |
| uint8_t byte = m_objectStartBitMap[mapIndex] & ((1 << (bit + 1)) - 1); |
| while (!byte) { |
| ASSERT(mapIndex > 0); |
| byte = m_objectStartBitMap[--mapIndex]; |
| } |
| int leadingZeroes = numberOfLeadingZeroes(byte); |
| objectStartNumber = (mapIndex * 8) + 7 - leadingZeroes; |
| objectOffset = objectStartNumber * allocationGranularity; |
| Address objectAddress = objectOffset + payload(); |
| HeapObjectHeader* header = reinterpret_cast<HeapObjectHeader*>(objectAddress); |
| if (header->isFree()) |
| return nullptr; |
| ASSERT(header->checkHeader()); |
| return header; |
| } |
| |
| #if ENABLE(ASSERT) |
| static bool isUninitializedMemory(void* objectPointer, size_t objectSize) |
| { |
| // Scan through the object's fields and check that they are all zero. |
| Address* objectFields = reinterpret_cast<Address*>(objectPointer); |
| for (size_t i = 0; i < objectSize / sizeof(Address); ++i) { |
| if (objectFields[i] != 0) |
| return false; |
| } |
| return true; |
| } |
| #endif |
| |
| static void markPointer(Visitor* visitor, HeapObjectHeader* header) |
| { |
| ASSERT(header->checkHeader()); |
| const GCInfo* gcInfo = Heap::gcInfo(header->gcInfoIndex()); |
| if (gcInfo->hasVTable() && !vTableInitialized(header->payload())) { |
| // We hit this branch when a GC strikes before GarbageCollected<>'s |
| // constructor runs. |
| // |
| // class A : public GarbageCollected<A> { virtual void f() = 0; }; |
| // class B : public A { |
| // B() : A(foo()) { }; |
| // }; |
| // |
| // If foo() allocates something and triggers a GC, the vtable of A |
| // has not yet been initialized. In this case, we should mark the A |
| // object without tracing any member of the A object. |
| visitor->markHeaderNoTracing(header); |
| ASSERT(isUninitializedMemory(header->payload(), header->payloadSize())); |
| } else { |
| visitor->markHeader(header, gcInfo->m_trace); |
| } |
| } |
| |
| void NormalPage::checkAndMarkPointer(Visitor* visitor, Address address) |
| { |
| ASSERT(contains(address)); |
| HeapObjectHeader* header = findHeaderFromAddress(address); |
| if (!header || header->isDead()) |
| return; |
| markPointer(visitor, header); |
| } |
| |
| void NormalPage::markOrphaned() |
| { |
| // Zap the payload with a recognizable value to detect any incorrect |
| // cross thread pointer usage. |
| #if defined(ADDRESS_SANITIZER) |
| // This needs to zap poisoned memory as well. |
| // Force unpoison memory before memset. |
| ASAN_UNPOISON_MEMORY_REGION(payload(), payloadSize()); |
| #endif |
| OrphanedPagePool::asanDisabledMemset(payload(), OrphanedPagePool::orphanedZapValue, payloadSize()); |
| BasePage::markOrphaned(); |
| } |
| |
| void NormalPage::takeSnapshot(String dumpName, size_t pageIndex, ThreadState::GCSnapshotInfo& info, size_t* outFreeSize, size_t* outFreeCount) |
| { |
| dumpName.append(String::format("/pages/page_%lu", static_cast<unsigned long>(pageIndex))); |
| WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName); |
| |
| HeapObjectHeader* header = nullptr; |
| size_t liveCount = 0; |
| size_t deadCount = 0; |
| size_t freeCount = 0; |
| size_t liveSize = 0; |
| size_t deadSize = 0; |
| size_t freeSize = 0; |
| for (Address headerAddress = payload(); headerAddress < payloadEnd(); headerAddress += header->size()) { |
| header = reinterpret_cast<HeapObjectHeader*>(headerAddress); |
| if (header->isFree()) { |
| freeCount++; |
| freeSize += header->size(); |
| } else if (header->isMarked()) { |
| liveCount++; |
| liveSize += header->size(); |
| |
| size_t gcInfoIndex = header->gcInfoIndex(); |
| info.liveCount[gcInfoIndex]++; |
| info.liveSize[gcInfoIndex] += header->size(); |
| } else { |
| deadCount++; |
| deadSize += header->size(); |
| |
| size_t gcInfoIndex = header->gcInfoIndex(); |
| info.deadCount[gcInfoIndex]++; |
| info.deadSize[gcInfoIndex] += header->size(); |
| } |
| } |
| |
| pageDump->addScalar("live_count", "objects", liveCount); |
| pageDump->addScalar("dead_count", "objects", deadCount); |
| pageDump->addScalar("free_count", "objects", freeCount); |
| pageDump->addScalar("live_size", "bytes", liveSize); |
| pageDump->addScalar("dead_size", "bytes", deadSize); |
| pageDump->addScalar("free_size", "bytes", freeSize); |
| *outFreeSize = freeSize; |
| *outFreeCount = freeCount; |
| } |
| |
| #if ENABLE(ASSERT) |
| bool NormalPage::contains(Address addr) |
| { |
| Address blinkPageStart = roundToBlinkPageStart(address()); |
| ASSERT(blinkPageStart == address() - blinkGuardPageSize); // Page is at aligned address plus guard page size. |
| return blinkPageStart <= addr && addr < blinkPageStart + blinkPageSize; |
| } |
| #endif |
| |
| NormalPageHeap* NormalPage::heapForNormalPage() |
| { |
| return static_cast<NormalPageHeap*>(heap()); |
| } |
| |
| LargeObjectPage::LargeObjectPage(PageMemory* storage, BaseHeap* heap, size_t payloadSize) |
| : BasePage(storage, heap) |
| , m_payloadSize(payloadSize) |
| #if ENABLE(ASAN_CONTAINER_ANNOTATIONS) |
| , m_isVectorBackingPage(false) |
| #endif |
| { |
| } |
| |
| size_t LargeObjectPage::objectPayloadSizeForTesting() |
| { |
| markAsSwept(); |
| return payloadSize(); |
| } |
| |
| bool LargeObjectPage::isEmpty() |
| { |
| return !heapObjectHeader()->isMarked(); |
| } |
| |
| void LargeObjectPage::removeFromHeap() |
| { |
| static_cast<LargeObjectHeap*>(heap())->freeLargeObjectPage(this); |
| } |
| |
| void LargeObjectPage::sweep() |
| { |
| heapObjectHeader()->unmark(); |
| Heap::increaseMarkedObjectSize(size()); |
| } |
| |
| void LargeObjectPage::makeConsistentForGC() |
| { |
| HeapObjectHeader* header = heapObjectHeader(); |
| if (header->isMarked()) { |
| header->unmark(); |
| Heap::increaseMarkedObjectSize(size()); |
| } else { |
| header->markDead(); |
| } |
| } |
| |
| void LargeObjectPage::makeConsistentForMutator() |
| { |
| HeapObjectHeader* header = heapObjectHeader(); |
| if (header->isMarked()) |
| header->unmark(); |
| } |
| |
| #if defined(ADDRESS_SANITIZER) |
| void LargeObjectPage::poisonObjects(BlinkGC::ObjectsToPoison objectsToPoison, BlinkGC::Poisoning poisoning) |
| { |
| HeapObjectHeader* header = heapObjectHeader(); |
| if (objectsToPoison == BlinkGC::MarkedAndUnmarked || !header->isMarked()) { |
| if (poisoning == BlinkGC::SetPoison) |
| ASAN_POISON_MEMORY_REGION(header->payload(), header->payloadSize()); |
| else |
| ASAN_UNPOISON_MEMORY_REGION(header->payload(), header->payloadSize()); |
| } |
| } |
| #endif |
| |
| void LargeObjectPage::checkAndMarkPointer(Visitor* visitor, Address address) |
| { |
| ASSERT(contains(address)); |
| if (!containedInObjectPayload(address) || heapObjectHeader()->isDead()) |
| return; |
| markPointer(visitor, heapObjectHeader()); |
| } |
| |
| void LargeObjectPage::markOrphaned() |
| { |
| // Zap the payload with a recognizable value to detect any incorrect |
| // cross thread pointer usage. |
| OrphanedPagePool::asanDisabledMemset(payload(), OrphanedPagePool::orphanedZapValue, payloadSize()); |
| BasePage::markOrphaned(); |
| } |
| |
| void LargeObjectPage::takeSnapshot(String dumpName, size_t pageIndex, ThreadState::GCSnapshotInfo& info, size_t* outFreeSize, size_t* outFreeCount) |
| { |
| dumpName.append(String::format("/pages/page_%lu", static_cast<unsigned long>(pageIndex))); |
| WebMemoryAllocatorDump* pageDump = BlinkGCMemoryDumpProvider::instance()->createMemoryAllocatorDumpForCurrentGC(dumpName); |
| |
| size_t liveSize = 0; |
| size_t deadSize = 0; |
| size_t liveCount = 0; |
| size_t deadCount = 0; |
| HeapObjectHeader* header = heapObjectHeader(); |
| size_t gcInfoIndex = header->gcInfoIndex(); |
| if (header->isMarked()) { |
| liveCount = 1; |
| liveSize += header->payloadSize(); |
| info.liveCount[gcInfoIndex]++; |
| info.liveSize[gcInfoIndex] += header->size(); |
| } else { |
| deadCount = 1; |
| deadSize += header->payloadSize(); |
| info.deadCount[gcInfoIndex]++; |
| info.deadSize[gcInfoIndex] += header->size(); |
| } |
| |
| pageDump->addScalar("live_count", "objects", liveCount); |
| pageDump->addScalar("dead_count", "objects", deadCount); |
| pageDump->addScalar("live_size", "bytes", liveSize); |
| pageDump->addScalar("dead_size", "bytes", deadSize); |
| } |
| |
| #if ENABLE(ASSERT) |
| bool LargeObjectPage::contains(Address object) |
| { |
| return roundToBlinkPageStart(address()) <= object && object < roundToBlinkPageEnd(address() + size()); |
| } |
| #endif |
| |
| void HeapDoesNotContainCache::flush() |
| { |
| if (m_hasEntries) { |
| for (int i = 0; i < numberOfEntries; ++i) |
| m_entries[i] = nullptr; |
| m_hasEntries = false; |
| } |
| } |
| |
| size_t HeapDoesNotContainCache::hash(Address address) |
| { |
| size_t value = (reinterpret_cast<size_t>(address) >> blinkPageSizeLog2); |
| value ^= value >> numberOfEntriesLog2; |
| value ^= value >> (numberOfEntriesLog2 * 2); |
| value &= numberOfEntries - 1; |
| return value & ~1; // Returns only even number. |
| } |
| |
| bool HeapDoesNotContainCache::lookup(Address address) |
| { |
| ASSERT(ThreadState::current()->isInGC()); |
| |
| size_t index = hash(address); |
| ASSERT(!(index & 1)); |
| Address cachePage = roundToBlinkPageStart(address); |
| if (m_entries[index] == cachePage) |
| return m_entries[index]; |
| if (m_entries[index + 1] == cachePage) |
| return m_entries[index + 1]; |
| return false; |
| } |
| |
| void HeapDoesNotContainCache::addEntry(Address address) |
| { |
| ASSERT(ThreadState::current()->isInGC()); |
| |
| m_hasEntries = true; |
| size_t index = hash(address); |
| ASSERT(!(index & 1)); |
| Address cachePage = roundToBlinkPageStart(address); |
| m_entries[index + 1] = m_entries[index]; |
| m_entries[index] = cachePage; |
| } |
| |
| } // namespace blink |
