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// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/snapshot/serializer.h"
#include "src/macro-assembler.h"
#include "src/snapshot/natives.h"
namespace v8 {
namespace internal {
Serializer::Serializer(Isolate* isolate)
: isolate_(isolate),
external_reference_encoder_(isolate),
root_index_map_(isolate),
recursion_depth_(0),
code_address_map_(NULL),
num_maps_(0),
large_objects_total_size_(0),
seen_large_objects_index_(0) {
// The serializer is meant to be used only to generate initial heap images
// from a context in which there is only one isolate.
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
pending_chunk_[i] = 0;
max_chunk_size_[i] = static_cast<uint32_t>(
MemoryAllocator::PageAreaSize(static_cast<AllocationSpace>(i)));
}
#ifdef OBJECT_PRINT
if (FLAG_serialization_statistics) {
instance_type_count_ = NewArray<int>(kInstanceTypes);
instance_type_size_ = NewArray<size_t>(kInstanceTypes);
for (int i = 0; i < kInstanceTypes; i++) {
instance_type_count_[i] = 0;
instance_type_size_[i] = 0;
}
} else {
instance_type_count_ = NULL;
instance_type_size_ = NULL;
}
#endif // OBJECT_PRINT
}
Serializer::~Serializer() {
if (code_address_map_ != NULL) delete code_address_map_;
#ifdef OBJECT_PRINT
if (instance_type_count_ != NULL) {
DeleteArray(instance_type_count_);
DeleteArray(instance_type_size_);
}
#endif // OBJECT_PRINT
}
#ifdef OBJECT_PRINT
void Serializer::CountInstanceType(Map* map, int size) {
int instance_type = map->instance_type();
instance_type_count_[instance_type]++;
instance_type_size_[instance_type] += size;
}
#endif // OBJECT_PRINT
void Serializer::OutputStatistics(const char* name) {
if (!FLAG_serialization_statistics) return;
PrintF("%s:\n", name);
PrintF(" Spaces (bytes):\n");
for (int space = 0; space < kNumberOfSpaces; space++) {
PrintF("%16s", AllocationSpaceName(static_cast<AllocationSpace>(space)));
}
PrintF("\n");
for (int space = 0; space < kNumberOfPreallocatedSpaces; space++) {
size_t s = pending_chunk_[space];
for (uint32_t chunk_size : completed_chunks_[space]) s += chunk_size;
PrintF("%16" PRIuS, s);
}
PrintF("%16d\n", large_objects_total_size_);
#ifdef OBJECT_PRINT
PrintF(" Instance types (count and bytes):\n");
#define PRINT_INSTANCE_TYPE(Name) \
if (instance_type_count_[Name]) { \
PrintF("%10d %10" PRIuS " %s\n", instance_type_count_[Name], \
instance_type_size_[Name], #Name); \
}
INSTANCE_TYPE_LIST(PRINT_INSTANCE_TYPE)
#undef PRINT_INSTANCE_TYPE
PrintF("\n");
#endif // OBJECT_PRINT
}
void Serializer::SerializeDeferredObjects() {
while (deferred_objects_.length() > 0) {
HeapObject* obj = deferred_objects_.RemoveLast();
ObjectSerializer obj_serializer(this, obj, &sink_, kPlain, kStartOfObject);
obj_serializer.SerializeDeferred();
}
sink_.Put(kSynchronize, "Finished with deferred objects");
}
void Serializer::VisitPointers(Object** start, Object** end) {
for (Object** current = start; current < end; current++) {
if ((*current)->IsSmi()) {
PutSmi(Smi::cast(*current));
} else {
SerializeObject(HeapObject::cast(*current), kPlain, kStartOfObject, 0);
}
}
}
void Serializer::EncodeReservations(
List<SerializedData::Reservation>* out) const {
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
for (int j = 0; j < completed_chunks_[i].length(); j++) {
out->Add(SerializedData::Reservation(completed_chunks_[i][j]));
}
if (pending_chunk_[i] > 0 || completed_chunks_[i].length() == 0) {
out->Add(SerializedData::Reservation(pending_chunk_[i]));
}
out->last().mark_as_last();
}
out->Add(SerializedData::Reservation(num_maps_ * Map::kSize));
out->last().mark_as_last();
out->Add(SerializedData::Reservation(large_objects_total_size_));
out->last().mark_as_last();
}
#ifdef DEBUG
bool Serializer::BackReferenceIsAlreadyAllocated(
SerializerReference reference) {
DCHECK(reference.is_back_reference());
AllocationSpace space = reference.space();
if (space == LO_SPACE) {
return reference.large_object_index() < seen_large_objects_index_;
} else if (space == MAP_SPACE) {
return reference.map_index() < num_maps_;
} else {
int chunk_index = reference.chunk_index();
if (chunk_index == completed_chunks_[space].length()) {
return reference.chunk_offset() < pending_chunk_[space];
} else {
return chunk_index < completed_chunks_[space].length() &&
reference.chunk_offset() < completed_chunks_[space][chunk_index];
}
}
}
#endif // DEBUG
bool Serializer::SerializeHotObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
if (how_to_code != kPlain || where_to_point != kStartOfObject) return false;
// Encode a reference to a hot object by its index in the working set.
int index = hot_objects_.Find(obj);
if (index == HotObjectsList::kNotFound) return false;
DCHECK(index >= 0 && index < kNumberOfHotObjects);
if (FLAG_trace_serializer) {
PrintF(" Encoding hot object %d:", index);
obj->ShortPrint();
PrintF("\n");
}
if (skip != 0) {
sink_.Put(kHotObjectWithSkip + index, "HotObjectWithSkip");
sink_.PutInt(skip, "HotObjectSkipDistance");
} else {
sink_.Put(kHotObject + index, "HotObject");
}
return true;
}
bool Serializer::SerializeBackReference(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
SerializerReference reference = reference_map_.Lookup(obj);
if (!reference.is_valid()) return false;
// Encode the location of an already deserialized object in order to write
// its location into a later object. We can encode the location as an
// offset fromthe start of the deserialized objects or as an offset
// backwards from thecurrent allocation pointer.
if (reference.is_attached_reference()) {
FlushSkip(skip);
if (FLAG_trace_serializer) {
PrintF(" Encoding attached reference %d\n",
reference.attached_reference_index());
}
PutAttachedReference(reference, how_to_code, where_to_point);
} else {
DCHECK(reference.is_back_reference());
if (FLAG_trace_serializer) {
PrintF(" Encoding back reference to: ");
obj->ShortPrint();
PrintF("\n");
}
PutAlignmentPrefix(obj);
AllocationSpace space = reference.space();
if (skip == 0) {
sink_.Put(kBackref + how_to_code + where_to_point + space, "BackRef");
} else {
sink_.Put(kBackrefWithSkip + how_to_code + where_to_point + space,
"BackRefWithSkip");
sink_.PutInt(skip, "BackRefSkipDistance");
}
PutBackReference(obj, reference);
}
return true;
}
void Serializer::PutRoot(int root_index, HeapObject* object,
SerializerDeserializer::HowToCode how_to_code,
SerializerDeserializer::WhereToPoint where_to_point,
int skip) {
if (FLAG_trace_serializer) {
PrintF(" Encoding root %d:", root_index);
object->ShortPrint();
PrintF("\n");
}
if (how_to_code == kPlain && where_to_point == kStartOfObject &&
root_index < kNumberOfRootArrayConstants &&
!isolate()->heap()->InNewSpace(object)) {
if (skip == 0) {
sink_.Put(kRootArrayConstants + root_index, "RootConstant");
} else {
sink_.Put(kRootArrayConstantsWithSkip + root_index, "RootConstant");
sink_.PutInt(skip, "SkipInPutRoot");
}
} else {
FlushSkip(skip);
sink_.Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
sink_.PutInt(root_index, "root_index");
hot_objects_.Add(object);
}
}
void Serializer::PutSmi(Smi* smi) {
sink_.Put(kOnePointerRawData, "Smi");
byte* bytes = reinterpret_cast<byte*>(&smi);
for (int i = 0; i < kPointerSize; i++) sink_.Put(bytes[i], "Byte");
}
void Serializer::PutBackReference(HeapObject* object,
SerializerReference reference) {
DCHECK(BackReferenceIsAlreadyAllocated(reference));
sink_.PutInt(reference.back_reference(), "BackRefValue");
hot_objects_.Add(object);
}
void Serializer::PutAttachedReference(SerializerReference reference,
HowToCode how_to_code,
WhereToPoint where_to_point) {
DCHECK(reference.is_attached_reference());
DCHECK((how_to_code == kPlain && where_to_point == kStartOfObject) ||
(how_to_code == kPlain && where_to_point == kInnerPointer) ||
(how_to_code == kFromCode && where_to_point == kStartOfObject) ||
(how_to_code == kFromCode && where_to_point == kInnerPointer));
sink_.Put(kAttachedReference + how_to_code + where_to_point, "AttachedRef");
sink_.PutInt(reference.attached_reference_index(), "AttachedRefIndex");
}
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;
}
SerializerReference Serializer::AllocateLargeObject(int size) {
// Large objects are allocated one-by-one when deserializing. We do not
// have to keep track of multiple chunks.
large_objects_total_size_ += size;
return SerializerReference::LargeObjectReference(seen_large_objects_index_++);
}
SerializerReference Serializer::AllocateMap() {
// Maps are allocated one-by-one when deserializing.
return SerializerReference::MapReference(num_maps_++);
}
SerializerReference Serializer::Allocate(AllocationSpace space, int size) {
DCHECK(space >= 0 && space < kNumberOfPreallocatedSpaces);
DCHECK(size > 0 && size <= static_cast<int>(max_chunk_size(space)));
uint32_t new_chunk_size = pending_chunk_[space] + size;
if (new_chunk_size > max_chunk_size(space)) {
// The new chunk size would not fit onto a single page. Complete the
// current chunk and start a new one.
sink_.Put(kNextChunk, "NextChunk");
sink_.Put(space, "NextChunkSpace");
completed_chunks_[space].Add(pending_chunk_[space]);
pending_chunk_[space] = 0;
new_chunk_size = size;
}
uint32_t offset = pending_chunk_[space];
pending_chunk_[space] = new_chunk_size;
return SerializerReference::BackReference(
space, completed_chunks_[space].length(), offset);
}
void Serializer::Pad() {
// The non-branching GetInt will read up to 3 bytes too far, so we need
// to pad the snapshot to make sure we don't read over the end.
for (unsigned i = 0; i < sizeof(int32_t) - 1; i++) {
sink_.Put(kNop, "Padding");
}
// Pad up to pointer size for checksum.
while (!IsAligned(sink_.Position(), kPointerAlignment)) {
sink_.Put(kNop, "Padding");
}
}
void Serializer::InitializeCodeAddressMap() {
isolate_->InitializeLoggingAndCounters();
code_address_map_ = new CodeAddressMap(isolate_);
}
Code* Serializer::CopyCode(Code* code) {
code_buffer_.Rewind(0); // Clear buffer without deleting backing store.
int size = code->CodeSize();
code_buffer_.AddAll(Vector<byte>(code->address(), size));
return Code::cast(HeapObject::FromAddress(&code_buffer_.first()));
}
bool Serializer::HasNotExceededFirstPageOfEachSpace() {
for (int i = 0; i < kNumberOfPreallocatedSpaces; i++) {
if (!completed_chunks_[i].is_empty()) return false;
}
return true;
}
void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
int size, Map* map) {
if (serializer_->code_address_map_) {
const char* code_name =
serializer_->code_address_map_->Lookup(object_->address());
LOG(serializer_->isolate_,
CodeNameEvent(object_->address(), sink_->Position(), code_name));
}
SerializerReference back_reference;
if (space == LO_SPACE) {
sink_->Put(kNewObject + reference_representation_ + space,
"NewLargeObject");
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
if (object_->IsCode()) {
sink_->Put(EXECUTABLE, "executable large object");
} else {
sink_->Put(NOT_EXECUTABLE, "not executable large object");
}
back_reference = serializer_->AllocateLargeObject(size);
} else if (space == MAP_SPACE) {
DCHECK_EQ(Map::kSize, size);
back_reference = serializer_->AllocateMap();
sink_->Put(kNewObject + reference_representation_ + space, "NewMap");
// This is redundant, but we include it anyways.
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
} else {
int fill = serializer_->PutAlignmentPrefix(object_);
back_reference = serializer_->Allocate(space, size + fill);
sink_->Put(kNewObject + reference_representation_ + space, "NewObject");
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
}
#ifdef OBJECT_PRINT
if (FLAG_serialization_statistics) {
serializer_->CountInstanceType(map, size);
}
#endif // OBJECT_PRINT
// Mark this object as already serialized.
serializer_->reference_map()->Add(object_, back_reference);
// Serialize the map (first word of the object).
serializer_->SerializeObject(map, kPlain, kStartOfObject, 0);
}
void Serializer::ObjectSerializer::SerializeExternalString() {
// Instead of serializing this as an external string, we serialize
// an imaginary sequential string with the same content.
Isolate* isolate = serializer_->isolate();
DCHECK(object_->IsExternalString());
DCHECK(object_->map() != isolate->heap()->native_source_string_map());
ExternalString* string = ExternalString::cast(object_);
int length = string->length();
Map* map;
int content_size;
int allocation_size;
const byte* resource;
// Find the map and size for the imaginary sequential string.
bool internalized = object_->IsInternalizedString();
if (object_->IsExternalOneByteString()) {
map = internalized ? isolate->heap()->one_byte_internalized_string_map()
: isolate->heap()->one_byte_string_map();
allocation_size = SeqOneByteString::SizeFor(length);
content_size = length * kCharSize;
resource = reinterpret_cast<const byte*>(
ExternalOneByteString::cast(string)->resource()->data());
} else {
map = internalized ? isolate->heap()->internalized_string_map()
: isolate->heap()->string_map();
allocation_size = SeqTwoByteString::SizeFor(length);
content_size = length * kShortSize;
resource = reinterpret_cast<const byte*>(
ExternalTwoByteString::cast(string)->resource()->data());
}
AllocationSpace space =
(allocation_size > kMaxRegularHeapObjectSize) ? LO_SPACE : OLD_SPACE;
SerializePrologue(space, allocation_size, map);
// Output the rest of the imaginary string.
int bytes_to_output = allocation_size - HeapObject::kHeaderSize;
// Output raw data header. Do not bother with common raw length cases here.
sink_->Put(kVariableRawData, "RawDataForString");
sink_->PutInt(bytes_to_output, "length");
// Serialize string header (except for map).
Address string_start = string->address();
for (int i = HeapObject::kHeaderSize; i < SeqString::kHeaderSize; i++) {
sink_->PutSection(string_start[i], "StringHeader");
}
// Serialize string content.
sink_->PutRaw(resource, content_size, "StringContent");
// Since the allocation size is rounded up to object alignment, there
// maybe left-over bytes that need to be padded.
int padding_size = allocation_size - SeqString::kHeaderSize - content_size;
DCHECK(0 <= padding_size && padding_size < kObjectAlignment);
for (int i = 0; i < padding_size; i++) sink_->PutSection(0, "StringPadding");
sink_->Put(kSkip, "SkipAfterString");
sink_->PutInt(bytes_to_output, "SkipDistance");
}
// Clear and later restore the next link in the weak cell or allocation site.
// TODO(all): replace this with proper iteration of weak slots in serializer.
class UnlinkWeakNextScope {
public:
explicit UnlinkWeakNextScope(HeapObject* object) : object_(nullptr) {
if (object->IsWeakCell()) {
object_ = object;
next_ = WeakCell::cast(object)->next();
WeakCell::cast(object)->clear_next(object->GetHeap()->the_hole_value());
} else if (object->IsAllocationSite()) {
object_ = object;
next_ = AllocationSite::cast(object)->weak_next();
AllocationSite::cast(object)->set_weak_next(
object->GetHeap()->undefined_value());
}
}
~UnlinkWeakNextScope() {
if (object_ != nullptr) {
if (object_->IsWeakCell()) {
WeakCell::cast(object_)->set_next(next_, UPDATE_WEAK_WRITE_BARRIER);
} else {
AllocationSite::cast(object_)->set_weak_next(next_,
UPDATE_WEAK_WRITE_BARRIER);
}
}
}
private:
HeapObject* object_;
Object* next_;
DisallowHeapAllocation no_gc_;
};
void Serializer::ObjectSerializer::Serialize() {
if (FLAG_trace_serializer) {
PrintF(" Encoding heap object: ");
object_->ShortPrint();
PrintF("\n");
}
// We cannot serialize typed array objects correctly.
DCHECK(!object_->IsJSTypedArray());
// We don't expect fillers.
DCHECK(!object_->IsFiller());
if (object_->IsScript()) {
// Clear cached line ends.
Object* undefined = serializer_->isolate()->heap()->undefined_value();
Script::cast(object_)->set_line_ends(undefined);
}
if (object_->IsExternalString()) {
Heap* heap = serializer_->isolate()->heap();
if (object_->map() != heap->native_source_string_map()) {
// Usually we cannot recreate resources for external strings. To work
// around this, external strings are serialized to look like ordinary
// sequential strings.
// The exception are native source code strings, since we can recreate
// their resources. In that case we fall through and leave it to
// VisitExternalOneByteString further down.
SerializeExternalString();
return;
}
}
int size = object_->Size();
Map* map = object_->map();
AllocationSpace space =
MemoryChunk::FromAddress(object_->address())->owner()->identity();
SerializePrologue(space, size, map);
// Serialize the rest of the object.
CHECK_EQ(0, bytes_processed_so_far_);
bytes_processed_so_far_ = kPointerSize;
RecursionScope recursion(serializer_);
// Objects that are immediately post processed during deserialization
// cannot be deferred, since post processing requires the object content.
if (recursion.ExceedsMaximum() && CanBeDeferred(object_)) {
serializer_->QueueDeferredObject(object_);
sink_->Put(kDeferred, "Deferring object content");
return;
}
UnlinkWeakNextScope unlink_weak_next(object_);
object_->IterateBody(map->instance_type(), size, this);
OutputRawData(object_->address() + size);
}
void Serializer::ObjectSerializer::SerializeDeferred() {
if (FLAG_trace_serializer) {
PrintF(" Encoding deferred heap object: ");
object_->ShortPrint();
PrintF("\n");
}
int size = object_->Size();
Map* map = object_->map();
SerializerReference back_reference =
serializer_->reference_map()->Lookup(object_);
DCHECK(back_reference.is_back_reference());
// Serialize the rest of the object.
CHECK_EQ(0, bytes_processed_so_far_);
bytes_processed_so_far_ = kPointerSize;
serializer_->PutAlignmentPrefix(object_);
sink_->Put(kNewObject + back_reference.space(), "deferred object");
serializer_->PutBackReference(object_, back_reference);
sink_->PutInt(size >> kPointerSizeLog2, "deferred object size");
UnlinkWeakNextScope unlink_weak_next(object_);
object_->IterateBody(map->instance_type(), size, this);
OutputRawData(object_->address() + size);
}
void Serializer::ObjectSerializer::VisitPointers(Object** start, Object** end) {
Object** current = start;
while (current < end) {
while (current < end && (*current)->IsSmi()) current++;
if (current < end) OutputRawData(reinterpret_cast<Address>(current));
while (current < end && !(*current)->IsSmi()) {
HeapObject* current_contents = HeapObject::cast(*current);
int root_index = serializer_->root_index_map()->Lookup(current_contents);
// Repeats are not subject to the write barrier so we can only use
// immortal immovable root members. They are never in new space.
if (current != start && root_index != RootIndexMap::kInvalidRootIndex &&
Heap::RootIsImmortalImmovable(root_index) &&
current_contents == current[-1]) {
DCHECK(!serializer_->isolate()->heap()->InNewSpace(current_contents));
int repeat_count = 1;
while (&current[repeat_count] < end - 1 &&
current[repeat_count] == current_contents) {
repeat_count++;
}
current += repeat_count;
bytes_processed_so_far_ += repeat_count * kPointerSize;
if (repeat_count > kNumberOfFixedRepeat) {
sink_->Put(kVariableRepeat, "VariableRepeat");
sink_->PutInt(repeat_count, "repeat count");
} else {
sink_->Put(kFixedRepeatStart + repeat_count, "FixedRepeat");
}
} else {
serializer_->SerializeObject(current_contents, kPlain, kStartOfObject,
0);
bytes_processed_so_far_ += kPointerSize;
current++;
}
}
}
}
void Serializer::ObjectSerializer::VisitEmbeddedPointer(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
Object* object = rinfo->target_object();
serializer_->SerializeObject(HeapObject::cast(object), how_to_code,
kStartOfObject, skip);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitExternalReference(Address* p) {
int skip = OutputRawData(reinterpret_cast<Address>(p),
kCanReturnSkipInsteadOfSkipping);
sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = *p;
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += kPointerSize;
}
void Serializer::ObjectSerializer::VisitExternalReference(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = rinfo->target_external_reference();
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitInternalReference(RelocInfo* rinfo) {
// We can only reference to internal references of code that has been output.
DCHECK(object_->IsCode() && code_has_been_output_);
// We do not use skip from last patched pc to find the pc to patch, since
// target_address_address may not return addresses in ascending order when
// used for internal references. External references may be stored at the
// end of the code in the constant pool, whereas internal references are
// inline. That would cause the skip to be negative. Instead, we store the
// offset from code entry.
Address entry = Code::cast(object_)->entry();
intptr_t pc_offset = rinfo->target_internal_reference_address() - entry;
intptr_t target_offset = rinfo->target_internal_reference() - entry;
DCHECK(0 <= pc_offset &&
pc_offset <= Code::cast(object_)->instruction_size());
DCHECK(0 <= target_offset &&
target_offset <= Code::cast(object_)->instruction_size());
sink_->Put(rinfo->rmode() == RelocInfo::INTERNAL_REFERENCE
? kInternalReference
: kInternalReferenceEncoded,
"InternalRef");
sink_->PutInt(static_cast<uintptr_t>(pc_offset), "internal ref address");
sink_->PutInt(static_cast<uintptr_t>(target_offset), "internal ref value");
}
void Serializer::ObjectSerializer::VisitRuntimeEntry(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
HowToCode how_to_code = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
sink_->Put(kExternalReference + how_to_code + kStartOfObject, "ExternalRef");
sink_->PutInt(skip, "SkipB4ExternalRef");
Address target = rinfo->target_address();
sink_->PutInt(serializer_->EncodeExternalReference(target), "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeTarget(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->target_address_address(),
kCanReturnSkipInsteadOfSkipping);
Code* object = Code::GetCodeFromTargetAddress(rinfo->target_address());
serializer_->SerializeObject(object, kFromCode, kInnerPointer, skip);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeEntry(Address entry_address) {
int skip = OutputRawData(entry_address, kCanReturnSkipInsteadOfSkipping);
Code* object = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
serializer_->SerializeObject(object, kPlain, kInnerPointer, skip);
bytes_processed_so_far_ += kPointerSize;
}
void Serializer::ObjectSerializer::VisitCell(RelocInfo* rinfo) {
int skip = OutputRawData(rinfo->pc(), kCanReturnSkipInsteadOfSkipping);
Cell* object = Cell::cast(rinfo->target_cell());
serializer_->SerializeObject(object, kPlain, kInnerPointer, skip);
bytes_processed_so_far_ += kPointerSize;
}
bool Serializer::ObjectSerializer::SerializeExternalNativeSourceString(
int builtin_count,
v8::String::ExternalOneByteStringResource** resource_pointer,
FixedArray* source_cache, int resource_index) {
Isolate* isolate = serializer_->isolate();
for (int i = 0; i < builtin_count; i++) {
Object* source = source_cache->get(i);
if (!source->IsUndefined(isolate)) {
ExternalOneByteString* string = ExternalOneByteString::cast(source);
typedef v8::String::ExternalOneByteStringResource Resource;
const Resource* resource = string->resource();
if (resource == *resource_pointer) {
sink_->Put(resource_index, "NativesStringResource");
sink_->PutSection(i, "NativesStringResourceEnd");
bytes_processed_so_far_ += sizeof(resource);
return true;
}
}
}
return false;
}
void Serializer::ObjectSerializer::VisitExternalOneByteString(
v8::String::ExternalOneByteStringResource** resource_pointer) {
DCHECK_EQ(serializer_->isolate()->heap()->native_source_string_map(),
object_->map());
DCHECK(ExternalOneByteString::cast(object_)->is_short());
Address references_start = reinterpret_cast<Address>(resource_pointer);
OutputRawData(references_start);
if (SerializeExternalNativeSourceString(
Natives::GetBuiltinsCount(), resource_pointer,
Natives::GetSourceCache(serializer_->isolate()->heap()),
kNativesStringResource)) {
return;
}
if (SerializeExternalNativeSourceString(
ExtraNatives::GetBuiltinsCount(), resource_pointer,
ExtraNatives::GetSourceCache(serializer_->isolate()->heap()),
kExtraNativesStringResource)) {
return;
}
// One of the strings in the natives cache should match the resource. We
// don't expect any other kinds of external strings here.
UNREACHABLE();
}
Address Serializer::ObjectSerializer::PrepareCode() {
Code* code = Code::cast(object_);
if (FLAG_predictable) {
// To make snapshots reproducible, we make a copy of the code object
// and wipe all pointers in the copy, which we then serialize.
code = serializer_->CopyCode(code);
int mode_mask = RelocInfo::kCodeTargetMask |
RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT) |
RelocInfo::ModeMask(RelocInfo::EXTERNAL_REFERENCE) |
RelocInfo::ModeMask(RelocInfo::RUNTIME_ENTRY) |
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE) |
RelocInfo::ModeMask(RelocInfo::INTERNAL_REFERENCE_ENCODED);
for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
RelocInfo* rinfo = it.rinfo();
rinfo->WipeOut();
}
// We need to wipe out the header fields *after* wiping out the
// relocations, because some of these fields are needed for the latter.
code->WipeOutHeader();
}
// Code age headers are not serializable.
code->MakeYoung(serializer_->isolate());
return code->address();
}
int Serializer::ObjectSerializer::OutputRawData(
Address up_to, Serializer::ObjectSerializer::ReturnSkip return_skip) {
Address object_start = object_->address();
int base = bytes_processed_so_far_;
int up_to_offset = static_cast<int>(up_to - object_start);
int to_skip = up_to_offset - bytes_processed_so_far_;
int bytes_to_output = to_skip;
bytes_processed_so_far_ += to_skip;
// This assert will fail if the reloc info gives us the target_address_address
// locations in a non-ascending order. Luckily that doesn't happen.
DCHECK(to_skip >= 0);
bool outputting_code = false;
bool is_code_object = object_->IsCode();
if (to_skip != 0 && is_code_object && !code_has_been_output_) {
// Output the code all at once and fix later.
bytes_to_output = object_->Size() + to_skip - bytes_processed_so_far_;
outputting_code = true;
code_has_been_output_ = true;
}
if (bytes_to_output != 0 && (!is_code_object || outputting_code)) {
if (!outputting_code && bytes_to_output == to_skip &&
IsAligned(bytes_to_output, kPointerAlignment) &&
bytes_to_output <= kNumberOfFixedRawData * kPointerSize) {
int size_in_words = bytes_to_output >> kPointerSizeLog2;
sink_->PutSection(kFixedRawDataStart + size_in_words, "FixedRawData");
to_skip = 0; // This instruction includes skip.
} else {
// We always end up here if we are outputting the code of a code object.
sink_->Put(kVariableRawData, "VariableRawData");
sink_->PutInt(bytes_to_output, "length");
}
if (is_code_object) object_start = PrepareCode();
const char* description = is_code_object ? "Code" : "Byte";
sink_->PutRaw(object_start + base, bytes_to_output, description);
}
if (to_skip != 0 && return_skip == kIgnoringReturn) {
sink_->Put(kSkip, "Skip");
sink_->PutInt(to_skip, "SkipDistance");
to_skip = 0;
}
return to_skip;
}
} // namespace internal
} // namespace v8