AuroraMiddleware/v8
1
0
Fork 0
Code Issues 2 Pull Requests Releases Wiki Activity

Serializer: cache recent back references for shorter encoding.

Browse Source 
And some refactorings.

R=mvstanton@chromium.org

Review URL: https://codereview.chromium.org/766893002

Cr-Commit-Position: refs/heads/master@{#25629}
This commit is contained in:
yangguo 2014-12-03 01:12:28 -08:00 committed by Commit bot
parent 02cb54e3cc
commit 07584119ca
4 changed files with 240 additions and 146 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/flag-definitions.h
View File

@ -488,7 +488,7 @@ DEFINE_BOOL(trace_stub_failures, false,
DEFINE_BOOL(serialize_toplevel, true, "enable caching of toplevel scripts")
DEFINE_BOOL(serialize_inner, false, "enable caching of inner functions")
DEFINE_BOOL(trace_code_serializer, false, "print code serializer trace")
DEFINE_BOOL(trace_serializer, false, "print code serializer trace")
// compiler.cc
DEFINE_INT(min_preparse_length, 1024,

245
src/serialize.cc
View File

@ -794,10 +794,24 @@ HeapObject* Deserializer::ProcessNewObjectFromSerializedCode(HeapObject* obj) {
}
Object* Deserializer::ProcessBackRefInSerializedCode(Object* obj) {
if (obj->IsInternalizedString()) {
return String::cast(obj)->GetForwardedInternalizedString();
HeapObject* Deserializer::GetBackReferencedObject(int space) {
HeapObject* obj;
if (space == LO_SPACE) {
uint32_t index = source_->GetInt();
obj = deserialized_large_objects_[index];
} else {
BackReference back_reference(source_->GetInt());
DCHECK(space < kNumberOfPreallocatedSpaces);
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);
}
if (deserializing_user_code() && obj->IsInternalizedString()) {
obj = String::cast(obj)->GetForwardedInternalizedString();
}
hot_objects_.Add(obj);
return obj;
}
@ -904,7 +918,7 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
source_space != CODE_SPACE &&
source_space != OLD_DATA_SPACE);
while (current < limit) {
int data = source_->Get();
byte data = source_->Get();
switch (data) {
#define CASE_STATEMENT(where, how, within, space_number) \
case where + how + within + space_number: \
@ -945,9 +959,6 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
} else if (where == kBackref) { \
emit_write_barrier = (space_number == NEW_SPACE); \
new_object = GetBackReferencedObject(data & kSpaceMask); \
if (deserializing_user_code()) { \
new_object = ProcessBackRefInSerializedCode(new_object); \
} \
} else if (where == kBuiltin) { \
DCHECK(deserializing_user_code()); \
int builtin_id = source_->GetInt(); \
@ -968,9 +979,6 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
reinterpret_cast<Address>(current) + skip); \
emit_write_barrier = (space_number == NEW_SPACE); \
new_object = GetBackReferencedObject(data & kSpaceMask); \
if (deserializing_user_code()) { \
new_object = ProcessBackRefInSerializedCode(new_object); \
} \
} \
if (within == kInnerPointer) { \
if (space_number != CODE_SPACE || new_object->IsCode()) { \
@ -1111,7 +1119,7 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
break;
}
case kRepeat: {
case kVariableRepeat: {
int repeats = source_->GetInt();
Object* object = current[-1];
DCHECK(!isolate->heap()->InNewSpace(object));
@ -1122,11 +1130,13 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
STATIC_ASSERT(kRootArrayNumberOfConstantEncodings ==
Heap::kOldSpaceRoots);
STATIC_ASSERT(kMaxRepeats == 13);
case kConstantRepeat:
FOUR_CASES(kConstantRepeat + 1)
FOUR_CASES(kConstantRepeat + 5)
FOUR_CASES(kConstantRepeat + 9) {
STATIC_ASSERT(kMaxFixedRepeats == 15);
FOUR_CASES(kFixedRepeat)
FOUR_CASES(kFixedRepeat + 4)
FOUR_CASES(kFixedRepeat + 8)
case kFixedRepeat + 12:
case kFixedRepeat + 13:
case kFixedRepeat + 14: {
int repeats = RepeatsForCode(data);
Object* object = current[-1];
DCHECK(!isolate->heap()->InNewSpace(object));
@ -1261,6 +1271,27 @@ void Deserializer::ReadData(Object** current, Object** limit, int source_space,
break;
}
FOUR_CASES(kHotObjectWithSkip)
FOUR_CASES(kHotObjectWithSkip + 4) {
int skip = source_->GetInt();
current = reinterpret_cast<Object**>(
reinterpret_cast<Address>(current) + skip);
// Fall through.
}
FOUR_CASES(kHotObject)
FOUR_CASES(kHotObject + 4) {
int index = data & kHotObjectIndexMask;
*current = hot_objects_.Get(index);
if (write_barrier_needed && isolate->heap()->InNewSpace(*current)) {
Address current_address = reinterpret_cast<Address>(current);
isolate->heap()->RecordWrite(
current_object_address,
static_cast<int>(current_address - current_object_address));
}
current++;
break;
}
case kSynchronize: {
// If we get here then that indicates that you have a mismatch between
// the number of GC roots when serializing and deserializing.
@ -1324,7 +1355,7 @@ void StartupSerializer::VisitPointers(Object** start, Object** end) {
sink_->Put(kSkip, "Skip");
sink_->PutInt(kPointerSize, "SkipOneWord");
} else if ((*current)->IsSmi()) {
sink_->Put(kRawData + 1, "Smi");
sink_->Put(kOnePointerRawData, "Smi");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
}
@ -1352,7 +1383,7 @@ bool Serializer::ShouldBeSkipped(Object** current) {
void Serializer::VisitPointers(Object** start, Object** end) {
for (Object** current = start; current < end; current++) {
if ((*current)->IsSmi()) {
sink_->Put(kRawData + 1, "Smi");
sink_->Put(kOnePointerRawData, "Smi");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
}
@ -1426,24 +1457,61 @@ int PartialSerializer::PartialSnapshotCacheIndex(HeapObject* heap_object) {
}
// 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 from
// the start of the deserialized objects or as an offset backwards from the
// current allocation pointer.
void Serializer::SerializeBackReference(BackReference back_reference,
HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
AllocationSpace space = back_reference.space();
if (skip == 0) {
sink_->Put(kBackref + how_to_code + where_to_point + space, "BackRefSer");
} else {
sink_->Put(kBackrefWithSkip + how_to_code + where_to_point + space,
"BackRefSerWithSkip");
sink_->PutInt(skip, "BackRefSkipDistance");
bool Serializer::SerializeKnownObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
if (how_to_code == kPlain && where_to_point == kStartOfObject) {
// Encode a reference to a hot object by its index in the working set.
int index = hot_objects_.Find(obj);
if (index != HotObjectsList::kNotFound) {
DCHECK(index >= 0 && index <= kMaxHotObjectIndex);
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;
}
}
BackReference back_reference = back_reference_map_.Lookup(obj);
if (back_reference.is_valid()) {
// 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 (back_reference.is_source()) {
FlushSkip(skip);
if (FLAG_trace_serializer) PrintF(" Encoding source object\n");
DCHECK(how_to_code == kPlain && where_to_point == kStartOfObject);
sink_->Put(kAttachedReference + how_to_code + where_to_point, "Source");
sink_->PutInt(kSourceObjectReference, "kSourceObjectIndex");
} else {
if (FLAG_trace_serializer) {
PrintF(" Encoding back reference to: ");
obj->ShortPrint();
PrintF("\n");
}
sink_->PutInt(back_reference.reference(),
(space == LO_SPACE) ? "large object index" : "allocation");
AllocationSpace space = back_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");
}
sink_->PutInt(back_reference.reference(), "BackRefValue");
hot_objects_.Add(obj);
}
return true;
}
return false;
}
@ -1460,16 +1528,9 @@ void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
return;
}
BackReference back_reference = back_reference_map_.Lookup(obj);
if (back_reference.is_valid()) {
SerializeBackReference(back_reference, how_to_code, where_to_point, skip);
return;
}
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
if (skip != 0) {
sink_->Put(kSkip, "FlushPendingSkip");
sink_->PutInt(skip, "SkipDistance");
}
FlushSkip(skip);
// Object has not yet been serialized. Serialize it here.
ObjectSerializer object_serializer(this, obj, sink_, how_to_code,
@ -1479,7 +1540,7 @@ void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
void StartupSerializer::SerializeWeakReferences() {
// This phase comes right after the partial serialization (of the snapshot).
// This phase comes right after the serialization (of the snapshot).
// After we have done the partial serialization the partial snapshot cache
// will contain some references needed to decode the partial snapshot. We
// add one entry with 'undefined' which is the sentinel that the deserializer
@ -1496,6 +1557,12 @@ void Serializer::PutRoot(int root_index,
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 < kRootArrayNumberOfConstantEncodings &&
@ -1509,10 +1576,7 @@ void Serializer::PutRoot(int root_index,
sink_->PutInt(skip, "SkipInPutRoot");
}
} else {
if (skip != 0) {
sink_->Put(kSkip, "SkipFromPutRoot");
sink_->PutInt(skip, "SkipFromPutRootDistance");
}
FlushSkip(skip);
sink_->Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
sink_->PutInt(root_index, "root_index");
}
@ -1534,10 +1598,7 @@ void PartialSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
}
if (ShouldBeInThePartialSnapshotCache(obj)) {
if (skip != 0) {
sink_->Put(kSkip, "SkipFromSerializeObject");
sink_->PutInt(skip, "SkipDistanceFromSerializeObject");
}
FlushSkip(skip);
int cache_index = PartialSnapshotCacheIndex(obj);
sink_->Put(kPartialSnapshotCache + how_to_code + where_to_point,
@ -1554,16 +1615,10 @@ void PartialSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
// either in the root table or in the partial snapshot cache.
DCHECK(!obj->IsInternalizedString());
BackReference back_reference = back_reference_map_.Lookup(obj);
if (back_reference.is_valid()) {
SerializeBackReference(back_reference, how_to_code, where_to_point, skip);
return;
}
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
FlushSkip(skip);
if (skip != 0) {
sink_->Put(kSkip, "SkipFromSerializeObject");
sink_->PutInt(skip, "SkipDistanceFromSerializeObject");
}
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this, obj, sink_, how_to_code, where_to_point);
serializer.Serialize();
@ -1584,8 +1639,8 @@ void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
BackReference back_reference;
if (space == LO_SPACE) {
sink_->Put(kNewObject + reference_representation_ + space,
"new large object");
sink_->PutInt(size >> kObjectAlignmentBits, "Size in words");
"NewLargeObject");
sink_->PutInt(size >> kObjectAlignmentBits, "ObjectSizeInWords");
if (object_->IsCode()) {
sink_->Put(EXECUTABLE, "executable large object");
} else {
@ -1596,14 +1651,14 @@ void Serializer::ObjectSerializer::SerializePrologue(AllocationSpace space,
if (object_->NeedsToEnsureDoubleAlignment()) {
// Add wriggle room for double alignment padding.
back_reference = serializer_->Allocate(space, size + kPointerSize);
sink_->PutInt(kDoubleAlignmentSentinel, "double align");
sink_->PutInt(kDoubleAlignmentSentinel, "DoubleAlignSentinel");
} else {
back_reference = serializer_->Allocate(space, size);
}
sink_->Put(kNewObject + reference_representation_ + space, "new object");
sink_->Put(kNewObject + reference_representation_ + space, "NewObject");
int encoded_size = size >> kObjectAlignmentBits;
DCHECK_NE(kDoubleAlignmentSentinel, encoded_size);
sink_->PutInt(encoded_size, "Size in words");
sink_->PutInt(encoded_size, "ObjectSizeInWords");
}
// Mark this object as already serialized.
@ -1677,6 +1732,12 @@ void Serializer::ObjectSerializer::SerializeExternalString() {
void Serializer::ObjectSerializer::Serialize() {
if (FLAG_trace_serializer) {
PrintF(" Encoding heap object: ");
object_->ShortPrint();
PrintF("\n");
}
if (object_->IsExternalString()) {
Heap* heap = serializer_->isolate()->heap();
if (object_->map() != heap->native_source_string_map()) {
@ -1727,8 +1788,8 @@ void Serializer::ObjectSerializer::VisitPointers(Object** start,
}
current += repeat_count;
bytes_processed_so_far_ += repeat_count * kPointerSize;
if (repeat_count > kMaxRepeats) {
sink_->Put(kRepeat, "SerializeRepeats");
if (repeat_count > kMaxFixedRepeats) {
sink_->Put(kVariableRepeat, "SerializeRepeats");
sink_->PutInt(repeat_count, "SerializeRepeats");
} else {
sink_->Put(CodeForRepeats(repeat_count), "SerializeRepeats");
@ -1957,8 +2018,8 @@ BackReference Serializer::Allocate(AllocationSpace space, int 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, "move to next chunk");
sink_->Put(space, "space of next chunk");
sink_->Put(kNextChunk, "NextChunk");
sink_->Put(space, "NextChunkSpace");
completed_chunks_[space].Add(pending_chunk_[space]);
pending_chunk_[space] = 0;
new_chunk_size = size;
@ -1990,7 +2051,7 @@ ScriptData* CodeSerializer::Serialize(Isolate* isolate,
Handle<String> source) {
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF("[Serializing from");
Object* script = info->script();
if (script->IsScript()) Script::cast(script)->name()->ShortPrint();
@ -2030,33 +2091,13 @@ void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip) {
int root_index = root_index_map_.Lookup(obj);
if (root_index != RootIndexMap::kInvalidRootIndex) {
if (FLAG_trace_code_serializer) {
PrintF(" Encoding root: %d\n", root_index);
}
PutRoot(root_index, obj, how_to_code, where_to_point, skip);
return;
}
BackReference back_reference = back_reference_map_.Lookup(obj);
if (back_reference.is_valid()) {
if (back_reference.is_source()) {
DCHECK_EQ(source_, obj);
SerializeSourceObject(how_to_code, where_to_point);
} else {
if (FLAG_trace_code_serializer) {
PrintF(" Encoding back reference to: ");
obj->ShortPrint();
PrintF("\n");
}
SerializeBackReference(back_reference, how_to_code, where_to_point, skip);
}
return;
}
if (SerializeKnownObject(obj, how_to_code, where_to_point, skip)) return;
if (skip != 0) {
sink_->Put(kSkip, "SkipFromSerializeObject");
sink_->PutInt(skip, "SkipDistanceFromSerializeObject");
}
FlushSkip(skip);
if (obj->IsCode()) {
Code* code_object = Code::cast(obj);
@ -2109,12 +2150,6 @@ void CodeSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
void CodeSerializer::SerializeGeneric(HeapObject* heap_object,
HowToCode how_to_code,
WhereToPoint where_to_point) {
if (FLAG_trace_code_serializer) {
PrintF(" Encoding heap object: ");
heap_object->ShortPrint();
PrintF("\n");
}
if (heap_object->IsInternalizedString()) num_internalized_strings_++;
// Object has not yet been serialized. Serialize it here.
@ -2132,7 +2167,7 @@ void CodeSerializer::SerializeBuiltin(int builtin_index, HowToCode how_to_code,
DCHECK_LT(builtin_index, Builtins::builtin_count);
DCHECK_LE(0, builtin_index);
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF(" Encoding builtin: %s\n",
isolate()->builtins()->name(builtin_index));
}
@ -2152,7 +2187,7 @@ void CodeSerializer::SerializeCodeStub(uint32_t stub_key, HowToCode how_to_code,
int index = AddCodeStubKey(stub_key) + kCodeStubsBaseIndex;
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF(" Encoding code stub %s as %d\n",
CodeStub::MajorName(CodeStub::MajorKeyFromKey(stub_key), false),
index);
@ -2168,7 +2203,7 @@ void CodeSerializer::SerializeIC(Code* ic, HowToCode how_to_code,
// The IC may be implemented as a stub.
uint32_t stub_key = ic->stub_key();
if (stub_key != CodeStub::NoCacheKey()) {
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF(" %s is a code stub\n", Code::Kind2String(ic->kind()));
}
SerializeCodeStub(stub_key, how_to_code, where_to_point);
@ -2182,7 +2217,7 @@ void CodeSerializer::SerializeIC(Code* ic, HowToCode how_to_code,
Builtins::Name name = static_cast<Builtins::Name>(builtin_index);
Code* builtin = isolate()->builtins()->builtin(name);
if (builtin == ic) {
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF(" %s is a builtin\n", Code::Kind2String(ic->kind()));
}
DCHECK(ic->kind() == Code::KEYED_LOAD_IC ||
@ -2193,7 +2228,7 @@ void CodeSerializer::SerializeIC(Code* ic, HowToCode how_to_code,
}
// The IC may also just be a piece of code kept in the non_monomorphic_cache.
// In that case, just serialize as a normal code object.
if (FLAG_trace_code_serializer) {
if (FLAG_trace_serializer) {
PrintF(" %s has no special handling\n", Code::Kind2String(ic->kind()));
}
DCHECK(ic->kind() == Code::LOAD_IC || ic->kind() == Code::STORE_IC);
@ -2215,7 +2250,7 @@ int CodeSerializer::AddCodeStubKey(uint32_t stub_key) {
void CodeSerializer::SerializeSourceObject(HowToCode how_to_code,
WhereToPoint where_to_point) {
if (FLAG_trace_code_serializer) PrintF(" Encoding source object\n");
if (FLAG_trace_serializer) PrintF(" Encoding source object\n");
DCHECK(how_to_code == kPlain && where_to_point == kStartOfObject);
sink_->Put(kAttachedReference + how_to_code + where_to_point, "Source");

137
src/serialize.h
View File

@ -285,6 +285,43 @@ class BackReferenceMap : public AddressMapBase {
};
class HotObjectsList {
public:
HotObjectsList() : index_(0) {
for (int i = 0; i < kSize; i++) circular_queue_[i] = NULL;
}
void Add(HeapObject* object) {
circular_queue_[index_] = object;
index_ = (index_ + 1) & kSizeMask;
}
HeapObject* Get(int index) {
DCHECK_NE(NULL, circular_queue_[index]);
return circular_queue_[index];
}
static const int kNotFound = -1;
int Find(HeapObject* object) {
for (int i = 0; i < kSize; i++) {
if (circular_queue_[i] == object) return i;
}
return kNotFound;
}
static const int kSize = 8;
private:
STATIC_ASSERT(IS_POWER_OF_TWO(kSize));
static const int kSizeMask = kSize - 1;
HeapObject* circular_queue_[kSize];
int index_;
DISALLOW_COPY_AND_ASSIGN(HotObjectsList);
};
// The Serializer/Deserializer class is a common superclass for Serializer and
// Deserializer which is used to store common constants and methods used by
// both.
@ -303,6 +340,7 @@ class SerializerDeserializer: public ObjectVisitor {
enum Where {
kNewObject = 0, // Object is next in snapshot.
// 1-7 One per space.
// 0x8 Unused.
kRootArray = 0x9, // Object is found in root array.
kPartialSnapshotCache = 0xa, // Object is in the cache.
kExternalReference = 0xb, // Pointer to an external reference.
@ -346,38 +384,58 @@ class SerializerDeserializer: public ObjectVisitor {
// entire code in one memcpy, then fix up stuff with kSkip and other byte
// codes that overwrite data.
static const int kRawData = 0x20;
// Some common raw lengths: 0x21-0x3f. These autoadvance the current pointer.
// A tag emitted at strategic points in the snapshot to delineate sections.
// If the deserializer does not find these at the expected moments then it
// 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 = 0x70;
// 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 = 0x71;
static const int kRepeat = 0x72;
static const int kConstantRepeat = 0x73;
// 0x73-0x7f Repeat last word (subtract 0x72 to get the count).
static const int kMaxRepeats = 0x7f - 0x72;
// Some common raw lengths: 0x21-0x3f.
// These autoadvance the current pointer.
static const int kOnePointerRawData = 0x21;
static const int kVariableRepeat = 0x60;
// 0x61-0x6f Repeat last word
static const int kFixedRepeat = 0x61;
static const int kFixedRepeatBase = kFixedRepeat - 1;
static const int kLastFixedRepeat = 0x6f;
static const int kMaxFixedRepeats = kLastFixedRepeat - kFixedRepeatBase;
static int CodeForRepeats(int repeats) {
DCHECK(repeats >= 1 && repeats <= kMaxRepeats);
return 0x72 + repeats;
DCHECK(repeats >= 1 && repeats <= kMaxFixedRepeats);
return kFixedRepeatBase + repeats;
}
static int RepeatsForCode(int byte_code) {
DCHECK(byte_code >= kConstantRepeat && byte_code <= 0x7f);
return byte_code - 0x72;
DCHECK(byte_code > kFixedRepeatBase && byte_code <= kLastFixedRepeat);
return byte_code - kFixedRepeatBase;
}
// Hot objects are a small set of recently seen or back-referenced objects.
// They are represented by a single opcode to save space.
// We use 0x70..0x77 for 8 hot objects, and 0x78..0x7f to add skip.
static const int kHotObject = 0x70;
static const int kMaxHotObjectIndex = 0x77 - kHotObject;
static const int kHotObjectWithSkip = 0x78;
STATIC_ASSERT(HotObjectsList::kSize == kMaxHotObjectIndex + 1);
STATIC_ASSERT(0x7f - kHotObjectWithSkip == kMaxHotObjectIndex);
static const int kHotObjectIndexMask = 0x7;
static const int kRootArrayConstants = 0xa0;
// 0xa0-0xbf Things from the first 32 elements of the root array.
// 0xa0-0xbf Things from the first 32 elements of the root array.
static const int kRootArrayNumberOfConstantEncodings = 0x20;
static int RootArrayConstantFromByteCode(int byte_code) {
return byte_code & 0x1f;
}
static const int kNop = 0xf; // Do nothing, used for padding.
// Do nothing, used for padding.
static const int kNop = 0xf;
static const int kNextChunk = 0x4f; // Move to next reserved chunk.
// Move to next reserved chunk.
static const int kNextChunk = 0x4f;
// A tag emitted at strategic points in the snapshot to delineate sections.
// If the deserializer does not find these at the expected moments then it
// 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 = 0x8f;
// 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 = 0xcf;
static const int kAnyOldSpace = -1;
@ -387,6 +445,11 @@ class SerializerDeserializer: public ObjectVisitor {
// Sentinel after a new object to indicate that double alignment is needed.
static const int kDoubleAlignmentSentinel = 0;
// Used as index for the attached reference representing the source object.
static const int kSourceObjectReference = 0;
HotObjectsList hot_objects_;
};
@ -449,24 +512,10 @@ class Deserializer: public SerializerDeserializer {
// Special handling for serialized code like hooking up internalized strings.
HeapObject* ProcessNewObjectFromSerializedCode(HeapObject* obj);
Object* ProcessBackRefInSerializedCode(Object* obj);
// This returns the address of an object that has been described in the
// snapshot by chunk index and offset.
HeapObject* GetBackReferencedObject(int space) {
if (space == LO_SPACE) {
uint32_t index = source_->GetInt();
return deserialized_large_objects_[index];
} else {
BackReference back_reference(source_->GetInt());
DCHECK(space < kNumberOfPreallocatedSpaces);
uint32_t chunk_index = back_reference.chunk_index();
DCHECK_LE(chunk_index, current_chunk_[space]);
uint32_t chunk_offset = back_reference.chunk_offset();
return HeapObject::FromAddress(reservations_[space][chunk_index].start +
chunk_offset);
}
}
HeapObject* GetBackReferencedObject(int space);
// Cached current isolate.
Isolate* isolate_;
@ -576,9 +625,17 @@ class Serializer : public SerializerDeserializer {
void PutRoot(int index, HeapObject* object, HowToCode how, WhereToPoint where,
int skip);
void SerializeBackReference(BackReference back_reference,
HowToCode how_to_code,
WhereToPoint where_to_point, int skip);
// Returns true if the object was successfully serialized.
bool SerializeKnownObject(HeapObject* obj, HowToCode how_to_code,
WhereToPoint where_to_point, int skip);
inline void FlushSkip(int skip) {
if (skip != 0) {
sink_->Put(kSkip, "SkipFromSerializeObject");
sink_->PutInt(skip, "SkipDistanceFromSerializeObject");
}
}
void InitializeAllocators();
// This will return the space for an object.
static AllocationSpace SpaceOfObject(HeapObject* object);
@ -716,6 +773,8 @@ class CodeSerializer : public Serializer {
Isolate* isolate, ScriptData* cached_data, Handle<String> source);
static const int kSourceObjectIndex = 0;
STATIC_ASSERT(kSourceObjectReference == kSourceObjectIndex);
static const int kCodeStubsBaseIndex = 1;
String* source() const {

2
src/snapshot-source-sink.h
View File

@ -24,7 +24,7 @@ class SnapshotByteSource FINAL {
bool HasMore() { return position_ < length_; }
int Get() {
byte Get() {
DCHECK(position_ < length_);
return data_[position_++];
}