diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc index 45303bd146..4573da1512 100644 --- a/src/code-stubs-hydrogen.cc +++ b/src/code-stubs-hydrogen.cc @@ -641,7 +641,7 @@ HValue* CodeStubGraphBuilder::BuildCodeStub() { HInstruction* value = GetParameter(CreateWeakCellDescriptor::kValueIndex); Add(object, HObjectAccess::ForWeakCellValue(), value); Add(object, HObjectAccess::ForWeakCellNext(), - graph()->GetConstantUndefined()); + graph()->GetConstantHole()); HInstruction* feedback_vector = GetParameter(CreateWeakCellDescriptor::kVectorIndex); diff --git a/src/heap/heap.cc b/src/heap/heap.cc index 80eb5620a8..39099fca1a 100644 --- a/src/heap/heap.cc +++ b/src/heap/heap.cc @@ -3102,7 +3102,7 @@ AllocationResult Heap::AllocateWeakCell(HeapObject* value) { } result->set_map_no_write_barrier(weak_cell_map()); WeakCell::cast(result)->initialize(value); - WeakCell::cast(result)->set_next(undefined_value(), SKIP_WRITE_BARRIER); + WeakCell::cast(result)->set_next(the_hole_value(), SKIP_WRITE_BARRIER); return result; } @@ -3706,19 +3706,18 @@ AllocationResult Heap::AllocateByteArray(int length, PretenureFlag pretenure) { void Heap::CreateFillerObjectAt(Address addr, int size) { if (size == 0) return; HeapObject* filler = HeapObject::FromAddress(addr); - // At this point, we may be deserializing the heap from a snapshot, and - // none of the maps have been created yet and are NULL. if (size == kPointerSize) { filler->set_map_no_write_barrier(raw_unchecked_one_pointer_filler_map()); - DCHECK(filler->map() == NULL || filler->map() == one_pointer_filler_map()); } else if (size == 2 * kPointerSize) { filler->set_map_no_write_barrier(raw_unchecked_two_pointer_filler_map()); - DCHECK(filler->map() == NULL || filler->map() == two_pointer_filler_map()); } else { filler->set_map_no_write_barrier(raw_unchecked_free_space_map()); - DCHECK(filler->map() == NULL || filler->map() == free_space_map()); FreeSpace::cast(filler)->nobarrier_set_size(size); } + // At this point, we may be deserializing the heap from a snapshot, and + // none of the maps have been created yet and are NULL. + DCHECK(filler->map() == NULL && !deserialization_complete_ || + filler->map()->IsMap()); } diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc index b56af23c49..90fc13616c 100644 --- a/src/heap/mark-compact.cc +++ b/src/heap/mark-compact.cc @@ -2637,7 +2637,7 @@ void MarkCompactCollector::AbortWeakCollections() { void MarkCompactCollector::ProcessAndClearWeakCells() { - HeapObject* undefined = heap()->undefined_value(); + HeapObject* the_hole = heap()->the_hole_value(); Object* weak_cell_obj = heap()->encountered_weak_cells(); while (weak_cell_obj != Smi::FromInt(0)) { WeakCell* weak_cell = reinterpret_cast(weak_cell_obj); @@ -2672,19 +2672,19 @@ void MarkCompactCollector::ProcessAndClearWeakCells() { RecordSlot(slot, slot, *slot); } weak_cell_obj = weak_cell->next(); - weak_cell->set_next(undefined, SKIP_WRITE_BARRIER); + weak_cell->set_next(the_hole, SKIP_WRITE_BARRIER); } heap()->set_encountered_weak_cells(Smi::FromInt(0)); } void MarkCompactCollector::AbortWeakCells() { - Object* undefined = heap()->undefined_value(); + Object* the_hole = heap()->the_hole_value(); Object* weak_cell_obj = heap()->encountered_weak_cells(); while (weak_cell_obj != Smi::FromInt(0)) { WeakCell* weak_cell = reinterpret_cast(weak_cell_obj); weak_cell_obj = weak_cell->next(); - weak_cell->set_next(undefined, SKIP_WRITE_BARRIER); + weak_cell->set_next(the_hole, SKIP_WRITE_BARRIER); } heap()->set_encountered_weak_cells(Smi::FromInt(0)); } diff --git a/src/heap/objects-visiting-inl.h b/src/heap/objects-visiting-inl.h index 9cd08c0bff..433fc6deab 100644 --- a/src/heap/objects-visiting-inl.h +++ b/src/heap/objects-visiting-inl.h @@ -329,11 +329,11 @@ void StaticMarkingVisitor::VisitWeakCell(Map* map, HeapObject* object) { Heap* heap = map->GetHeap(); WeakCell* weak_cell = reinterpret_cast(object); - Object* undefined = heap->undefined_value(); + Object* the_hole = heap->the_hole_value(); // Enqueue weak cell in linked list of encountered weak collections. // We can ignore weak cells with cleared values because they will always // contain smi zero. - if (weak_cell->next() == undefined && !weak_cell->cleared()) { + if (weak_cell->next() == the_hole && !weak_cell->cleared()) { weak_cell->set_next(heap->encountered_weak_cells(), UPDATE_WEAK_WRITE_BARRIER); heap->set_encountered_weak_cells(weak_cell); diff --git a/src/snapshot/serialize.cc b/src/snapshot/serialize.cc index 8b382c09fb..026d60221d 100644 --- a/src/snapshot/serialize.cc +++ b/src/snapshot/serialize.cc @@ -753,6 +753,8 @@ HeapObject* Deserializer::PostProcessNewObject(HeapObject* obj, int space) { new_code_objects_.Add(Code::cast(obj)); } } + // Check alignment. + DCHECK_EQ(0, Heap::GetFillToAlign(obj->address(), obj->RequiredAlignment())); return obj; } @@ -769,8 +771,14 @@ HeapObject* Deserializer::GetBackReferencedObject(int space) { uint32_t chunk_index = back_reference.chunk_index(); DCHECK_LE(chunk_index, current_chunk_[space]); uint32_t chunk_offset = back_reference.chunk_offset(); - obj = HeapObject::FromAddress(reservations_[space][chunk_index].start + - chunk_offset); + Address address = reservations_[space][chunk_index].start + chunk_offset; + if (next_alignment_ != kWordAligned) { + int padding = Heap::GetFillToAlign(address, next_alignment_); + next_alignment_ = kWordAligned; + DCHECK(padding == 0 || HeapObject::FromAddress(address)->IsFiller()); + address += padding; + } + obj = HeapObject::FromAddress(address); } if (deserializing_user_code() && obj->IsInternalizedString()) { obj = String::cast(obj)->GetForwardedInternalizedString(); @@ -788,22 +796,25 @@ HeapObject* Deserializer::GetBackReferencedObject(int space) { void Deserializer::ReadObject(int space_number, Object** write_back) { Address address; HeapObject* obj; - int next_int = source_.GetInt(); + int size = source_.GetInt() << kObjectAlignmentBits; - bool double_align = false; -#ifndef V8_HOST_ARCH_64_BIT - double_align = next_int == kDoubleAlignmentSentinel; - if (double_align) next_int = source_.GetInt(); -#endif - - DCHECK_NE(kDoubleAlignmentSentinel, next_int); - int size = next_int << kObjectAlignmentBits; - int reserved_size = size + (double_align ? kPointerSize : 0); - address = Allocate(space_number, reserved_size); - obj = HeapObject::FromAddress(address); - if (double_align) { - obj = isolate_->heap()->DoubleAlignForDeserialization(obj, reserved_size); + if (next_alignment_ != kWordAligned) { + int reserved = size + Heap::GetMaximumFillToAlign(next_alignment_); + address = Allocate(space_number, reserved); + obj = HeapObject::FromAddress(address); + // If one of the following assertions fails, then we are deserializing an + // aligned object when the filler maps have not been deserialized yet. + // We require filler maps as padding to align the object. + Heap* heap = isolate_->heap(); + DCHECK(heap->free_space_map()->IsMap()); + DCHECK(heap->one_pointer_filler_map()->IsMap()); + DCHECK(heap->two_pointer_filler_map()->IsMap()); + obj = heap->AlignWithFiller(obj, size, reserved, next_alignment_); address = obj->address(); + next_alignment_ = kWordAligned; + } else { + address = Allocate(space_number, size); + obj = HeapObject::FromAddress(address); } isolate_->heap()->OnAllocationEvent(obj, size); @@ -998,14 +1009,17 @@ bool Deserializer::ReadData(Object** current, Object** limit, int source_space, FOUR_CASES(byte_code + 8) \ FOUR_CASES(byte_code + 12) +#define SINGLE_CASE(where, how, within, space) \ + CASE_STATEMENT(where, how, within, space) \ + CASE_BODY(where, how, within, space) + // Deserialize a new object and write a pointer to it to the current // object. ALL_SPACES(kNewObject, kPlain, kStartOfObject) // Support for direct instruction pointers in functions. It's an inner // pointer because it points at the entry point, not at the start of the // code object. - CASE_STATEMENT(kNewObject, kPlain, kInnerPointer, CODE_SPACE) - CASE_BODY(kNewObject, kPlain, kInnerPointer, CODE_SPACE) + SINGLE_CASE(kNewObject, kPlain, kInnerPointer, CODE_SPACE) // Deserialize a new code object and write a pointer to its first // instruction to the current code object. ALL_SPACES(kNewObject, kFromCode, kInnerPointer) @@ -1036,45 +1050,33 @@ bool Deserializer::ReadData(Object** current, Object** limit, int source_space, ALL_SPACES(kBackrefWithSkip, kPlain, kInnerPointer) // Find an object in the roots array and write a pointer to it to the // current object. - CASE_STATEMENT(kRootArray, kPlain, kStartOfObject, 0) - CASE_BODY(kRootArray, kPlain, kStartOfObject, 0) + SINGLE_CASE(kRootArray, kPlain, kStartOfObject, 0) #if defined(V8_TARGET_ARCH_MIPS) || defined(V8_TARGET_ARCH_MIPS64) || \ defined(V8_TARGET_ARCH_PPC) || V8_EMBEDDED_CONSTANT_POOL // Find an object in the roots array and write a pointer to it to in code. - CASE_STATEMENT(kRootArray, kFromCode, kStartOfObject, 0) - CASE_BODY(kRootArray, kFromCode, kStartOfObject, 0) + SINGLE_CASE(kRootArray, kFromCode, kStartOfObject, 0) #endif // Find an object in the partial snapshots cache and write a pointer to it // to the current object. - CASE_STATEMENT(kPartialSnapshotCache, kPlain, kStartOfObject, 0) - CASE_BODY(kPartialSnapshotCache, kPlain, kStartOfObject, 0) + SINGLE_CASE(kPartialSnapshotCache, kPlain, kStartOfObject, 0) // Find an code entry in the partial snapshots cache and // write a pointer to it to the current object. - CASE_STATEMENT(kPartialSnapshotCache, kPlain, kInnerPointer, 0) - CASE_BODY(kPartialSnapshotCache, kPlain, kInnerPointer, 0) + SINGLE_CASE(kPartialSnapshotCache, kPlain, kInnerPointer, 0) // Find an external reference and write a pointer to it to the current // object. - CASE_STATEMENT(kExternalReference, kPlain, kStartOfObject, 0) - CASE_BODY(kExternalReference, kPlain, kStartOfObject, 0) + SINGLE_CASE(kExternalReference, kPlain, kStartOfObject, 0) // Find an external reference and write a pointer to it in the current // code object. - CASE_STATEMENT(kExternalReference, kFromCode, kStartOfObject, 0) - CASE_BODY(kExternalReference, kFromCode, kStartOfObject, 0) + SINGLE_CASE(kExternalReference, kFromCode, kStartOfObject, 0) // Find an object in the attached references and write a pointer to it to // the current object. - CASE_STATEMENT(kAttachedReference, kPlain, kStartOfObject, 0) - CASE_BODY(kAttachedReference, kPlain, kStartOfObject, 0) - CASE_STATEMENT(kAttachedReference, kPlain, kInnerPointer, 0) - CASE_BODY(kAttachedReference, kPlain, kInnerPointer, 0) - CASE_STATEMENT(kAttachedReference, kFromCode, kInnerPointer, 0) - CASE_BODY(kAttachedReference, kFromCode, kInnerPointer, 0) + SINGLE_CASE(kAttachedReference, kPlain, kStartOfObject, 0) + SINGLE_CASE(kAttachedReference, kPlain, kInnerPointer, 0) + SINGLE_CASE(kAttachedReference, kFromCode, kInnerPointer, 0) // Find a builtin and write a pointer to it to the current object. - CASE_STATEMENT(kBuiltin, kPlain, kStartOfObject, 0) - CASE_BODY(kBuiltin, kPlain, kStartOfObject, 0) - CASE_STATEMENT(kBuiltin, kPlain, kInnerPointer, 0) - CASE_BODY(kBuiltin, kPlain, kInnerPointer, 0) - CASE_STATEMENT(kBuiltin, kFromCode, kInnerPointer, 0) - CASE_BODY(kBuiltin, kFromCode, kInnerPointer, 0) + SINGLE_CASE(kBuiltin, kPlain, kStartOfObject, 0) + SINGLE_CASE(kBuiltin, kPlain, kInnerPointer, 0) + SINGLE_CASE(kBuiltin, kFromCode, kInnerPointer, 0) #undef CASE_STATEMENT #undef CASE_BODY @@ -1169,6 +1171,15 @@ bool Deserializer::ReadData(Object** current, Object** limit, int source_space, break; } + case kAlignmentPrefix: + case kAlignmentPrefix + 1: + case kAlignmentPrefix + 2: { + DCHECK_EQ(kWordAligned, next_alignment_); + next_alignment_ = + static_cast(data - (kAlignmentPrefix - 1)); + break; + } + STATIC_ASSERT(kNumberOfRootArrayConstants == Heap::kOldSpaceRoots); STATIC_ASSERT(kNumberOfRootArrayConstants == 32); SIXTEEN_CASES(kRootArrayConstantsWithSkip) @@ -1235,6 +1246,7 @@ bool Deserializer::ReadData(Object** current, Object** limit, int source_space, #undef SIXTEEN_CASES #undef FOUR_CASES +#undef SINGLE_CASE default: CHECK(false); @@ -1562,6 +1574,7 @@ bool Serializer::SerializeKnownObject(HeapObject* obj, HowToCode how_to_code, PrintF("\n"); } + PutAlignmentPrefix(obj); AllocationSpace space = back_reference.space(); if (skip == 0) { sink_->Put(kBackref + how_to_code + where_to_point + space, "BackRef"); @@ -1655,6 +1668,18 @@ void Serializer::PutBackReference(HeapObject* object, BackReference reference) { } +int Serializer::PutAlignmentPrefix(HeapObject* object) { + AllocationAlignment alignment = object->RequiredAlignment(); + if (alignment != kWordAligned) { + DCHECK(1 <= alignment && alignment <= 3); + byte prefix = (kAlignmentPrefix - 1) + alignment; + sink_->Put(prefix, "Alignment"); + return Heap::GetMaximumFillToAlign(alignment); + } + return 0; +} + + void PartialSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code, WhereToPoint where_to_point, int skip) { if (obj->IsMap()) { @@ -1736,21 +1761,10 @@ void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space, } back_reference = serializer_->AllocateLargeObject(size); } else { - bool needs_double_align = false; - // TODO(bbudge): Generalize to other alignment constraints. - if (object_->RequiredAlignment() == kDoubleAligned) { - // Add wriggle room for double alignment padding. - back_reference = serializer_->Allocate(space, size + kPointerSize); - needs_double_align = true; - } else { - back_reference = serializer_->Allocate(space, size); - } + int fill = serializer_->PutAlignmentPrefix(object_); + back_reference = serializer_->Allocate(space, size + fill); sink_->Put(kNewObject + reference_representation_ + space, "NewObject"); - if (needs_double_align) - sink_->PutInt(kDoubleAlignmentSentinel, "DoubleAlignSentinel"); - int encoded_size = size >> kObjectAlignmentBits; - DCHECK_NE(kDoubleAlignmentSentinel, encoded_size); - sink_->PutInt(encoded_size, "ObjectSizeInWords"); + sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords"); } #ifdef OBJECT_PRINT diff --git a/src/snapshot/serialize.h b/src/snapshot/serialize.h index 089c323b7d..2a426a94f5 100644 --- a/src/snapshot/serialize.h +++ b/src/snapshot/serialize.h @@ -324,12 +324,14 @@ class SerializerDeserializer: public ObjectVisitor { // 0x07 Unused (including 0x27, 0x47, 0x67). // 0x08..0x0c Reference to previous object from space. kBackref = 0x08, + // 0x0d Unused (including 0x2d, 0x4d, 0x6d). // 0x0e Unused (including 0x2e, 0x4e, 0x6e). // 0x0f Unused (including 0x2f, 0x4f, 0x6f). // 0x10..0x14 Reference to previous object from space after skip. kBackrefWithSkip = 0x10, + // 0x15 Unused (including 0x35, 0x55, 0x75). // 0x16 Unused (including 0x36, 0x56, 0x76). - // 0x17 Unused (including 0x37, 0x57, 0x77). + // 0x17 Misc (including 0x37, 0x57, 0x77). // 0x18 Root array item. kRootArray = 0x18, // 0x19 Object in the partial snapshot cache. @@ -384,14 +386,18 @@ class SerializerDeserializer: public ObjectVisitor { // is an indication that the snapshot and the VM do not fit together. // Examine the build process for architecture, version or configuration // mismatches. - static const int kSynchronize = 0x5d; + static const int kSynchronize = 0x17; // Used for the source code of the natives, which is in the executable, but // is referred to from external strings in the snapshot. - static const int kNativesStringResource = 0x5e; + static const int kNativesStringResource = 0x37; // Raw data of variable length. - static const int kVariableRawData = 0x7d; + static const int kVariableRawData = 0x57; // Repeats of variable length. - static const int kVariableRepeat = 0x7e; + static const int kVariableRepeat = 0x77; + // Alignment prefixes 0x7d..0x7f + static const int kAlignmentPrefix = 0x7d; + + // 0x5d..0x5f unused // ---------- byte code range 0x80..0xff ---------- // First 32 root array items. @@ -515,7 +521,8 @@ class Deserializer: public SerializerDeserializer { magic_number_(data->GetMagicNumber()), external_reference_table_(NULL), deserialized_large_objects_(0), - deserializing_user_code_(false) { + deserializing_user_code_(false), + next_alignment_(kWordAligned) { DecodeReservation(data->Reservations()); } @@ -602,6 +609,8 @@ class Deserializer: public SerializerDeserializer { bool deserializing_user_code_; + AllocationAlignment next_alignment_; + DISALLOW_COPY_AND_ASSIGN(Deserializer); }; @@ -706,6 +715,9 @@ class Serializer : public SerializerDeserializer { void PutBackReference(HeapObject* object, BackReference reference); + // Emit alignment prefix if necessary, return required padding space in bytes. + int PutAlignmentPrefix(HeapObject* object); + // Returns true if the object was successfully serialized. bool SerializeKnownObject(HeapObject* obj, HowToCode how_to_code, WhereToPoint where_to_point, int skip);