serialize.cc.svn-base

Google浏览器V8内核代码

  // Stat counters
#define COUNTER_ENTRY(name, caption) \
  Add(reinterpret_cast<Address>(GetInternalPointer(&Counters::name)), \
      STATS_COUNTER, \
      Counters::k_##name, \
      "Counters::" #name);

  STATS_COUNTER_LIST_1(COUNTER_ENTRY)
  STATS_COUNTER_LIST_2(COUNTER_ENTRY)
#undef COUNTER_ENTRY

  // Top addresses
  const char* top_address_format = "Top::get_address_from_id(%i)";
  size_t top_format_length = strlen(top_address_format);
  for (uint16_t i = 0; i < Top::k_top_address_count; ++i) {
    Vector<char> name = Vector<char>::New(top_format_length + 1);
    const char* chars = name.start();
    OS::SNPrintF(name, top_address_format, i);
    Add(Top::get_address_from_id((Top::AddressId)i), TOP_ADDRESS, i, chars);
  }

  // Extensions
  Add(FUNCTION_ADDR(GCExtension::GC), EXTENSION, 1,
      "GCExtension::GC");
  Add(FUNCTION_ADDR(PrintExtension::Print), EXTENSION, 2,
      "PrintExtension::Print");
  Add(FUNCTION_ADDR(LoadExtension::Load), EXTENSION, 3,
      "LoadExtension::Load");
  Add(FUNCTION_ADDR(QuitExtension::Quit), EXTENSION, 4,
      "QuitExtension::Quit");

  // Accessors
#define ACCESSOR_DESCRIPTOR_DECLARATION(name) \
  Add((Address)&Accessors::name, \
      ACCESSOR, \
      Accessors::k##name, \
      "Accessors::" #name);

  ACCESSOR_DESCRIPTOR_LIST(ACCESSOR_DESCRIPTOR_DECLARATION)
#undef ACCESSOR_DESCRIPTOR_DECLARATION

  // Stub cache tables
  Add(SCTableReference::keyReference(StubCache::kPrimary).address(),
      STUB_CACHE_TABLE,
      1,
      "StubCache::primary_->key");
  Add(SCTableReference::valueReference(StubCache::kPrimary).address(),
      STUB_CACHE_TABLE,
      2,
      "StubCache::primary_->value");
  Add(SCTableReference::keyReference(StubCache::kSecondary).address(),
      STUB_CACHE_TABLE,
      3,
      "StubCache::secondary_->key");
  Add(SCTableReference::valueReference(StubCache::kSecondary).address(),
      STUB_CACHE_TABLE,
      4,
      "StubCache::secondary_->value");

  // Runtime entries
  Add(FUNCTION_ADDR(Runtime::PerformGC),
      RUNTIME_ENTRY,
      1,
      "Runtime::PerformGC");

  // Miscellaneous
  Add(ExternalReference::builtin_passed_function().address(),
      UNCLASSIFIED,
      1,
      "Builtins::builtin_passed_function");
  Add(ExternalReference::the_hole_value_location().address(),
      UNCLASSIFIED,
      2,
      "Factory::the_hole_value().location()");
  Add(ExternalReference::address_of_stack_guard_limit().address(),
      UNCLASSIFIED,
      3,
      "StackGuard::address_of_limit()");
  Add(ExternalReference::debug_break().address(),
      UNCLASSIFIED,
      4,
      "Debug::Break()");
  Add(ExternalReference::new_space_start().address(),
      UNCLASSIFIED,
      5,
      "Heap::NewSpaceStart()");
  Add(ExternalReference::new_space_allocation_limit_address().address(),
      UNCLASSIFIED,
      6,
      "Heap::NewSpaceAllocationLimitAddress()");
  Add(ExternalReference::new_space_allocation_top_address().address(),
      UNCLASSIFIED,
      7,
      "Heap::NewSpaceAllocationTopAddress()");
  Add(ExternalReference::debug_step_in_fp_address().address(),
      UNCLASSIFIED,
      8,
      "Debug::step_in_fp_addr()");
}


ExternalReferenceEncoder::ExternalReferenceEncoder()
    : encodings_(Match) {
  ExternalReferenceTable* external_references =
      ExternalReferenceTable::instance();
  for (int i = 0; i < external_references->size(); ++i) {
    Put(external_references->address(i), i);
  }
}


uint32_t ExternalReferenceEncoder::Encode(Address key) const {
  int index = IndexOf(key);
  return index >=0 ? ExternalReferenceTable::instance()->code(index) : 0;
}


const char* ExternalReferenceEncoder::NameOfAddress(Address key) const {
  int index = IndexOf(key);
  return index >=0 ? ExternalReferenceTable::instance()->name(index) : NULL;
}


int ExternalReferenceEncoder::IndexOf(Address key) const {
  if (key == NULL) return -1;
  HashMap::Entry* entry =
      const_cast<HashMap &>(encodings_).Lookup(key, Hash(key), false);
  return entry == NULL ? -1 : reinterpret_cast<int>(entry->value);
}


void ExternalReferenceEncoder::Put(Address key, int index) {
  HashMap::Entry* entry = encodings_.Lookup(key, Hash(key), true);
  entry->value = reinterpret_cast<void *>(index);
}


ExternalReferenceDecoder::ExternalReferenceDecoder()
  : encodings_(NewArray<Address*>(kTypeCodeCount)) {
  ExternalReferenceTable* external_references =
      ExternalReferenceTable::instance();
  for (int type = kFirstTypeCode; type < kTypeCodeCount; ++type) {
    int max = external_references->max_id(type) + 1;
    encodings_[type] = NewArray<Address>(max + 1);
  }
  for (int i = 0; i < external_references->size(); ++i) {
    Put(external_references->code(i), external_references->address(i));
  }
}


ExternalReferenceDecoder::~ExternalReferenceDecoder() {
  for (int type = kFirstTypeCode; type < kTypeCodeCount; ++type) {
    DeleteArray(encodings_[type]);
  }
  DeleteArray(encodings_);
}


//------------------------------------------------------------------------------
// Implementation of Serializer


// Helper class to write the bytes of the serialized heap.

class SnapshotWriter {
 public:
  SnapshotWriter() {
    len_ = 0;
    max_ = 8 << 10;  // 8K initial size
    str_ = NewArray<char>(max_);
  }

  ~SnapshotWriter() {
    DeleteArray(str_);
  }

  void GetString(char** str, int* len) {
    *str = NewArray<char>(len_);
    memcpy(*str, str_, len_);
    *len = len_;
  }

  void Reserve(int bytes, int pos);

  void PutC(char c) {
    InsertC(c, len_);
  }

  void PutInt(int i) {
    InsertInt(i, len_);
  }

  void PutBytes(const byte* a, int size) {
    InsertBytes(a, len_, size);
  }

  void PutString(const char* s) {
    InsertString(s, len_);
  }

  int InsertC(char c, int pos) {
    Reserve(1, pos);
    str_[pos] = c;
    len_++;
    return pos + 1;
  }

  int InsertInt(int i, int pos) {
    return InsertBytes(reinterpret_cast<byte*>(&i), pos, sizeof(i));
  }

  int InsertBytes(const byte* a, int pos, int size) {
    Reserve(size, pos);
    memcpy(&str_[pos], a, size);
    len_ += size;
    return pos + size;
  }

  int InsertString(const char* s, int pos);

  int length() { return len_; }

  Address position() { return reinterpret_cast<Address>(&str_[len_]); }

 private:
  char* str_;  // the snapshot
  int len_;   // the curent length of str_
  int max_;   // the allocated size of str_
};


void SnapshotWriter::Reserve(int bytes, int pos) {
  CHECK(0 <= pos && pos <= len_);
  while (len_ + bytes >= max_) {
    max_ *= 2;
    char* old = str_;
    str_ = NewArray<char>(max_);
    memcpy(str_, old, len_);
    DeleteArray(old);
  }
  if (pos < len_) {
    char* old = str_;
    str_ = NewArray<char>(max_);
    memcpy(str_, old, pos);
    memcpy(str_ + pos + bytes, old + pos, len_ - pos);
    DeleteArray(old);
  }
}

int SnapshotWriter::InsertString(const char* s, int pos) {
  int size = strlen(s);
  pos = InsertC('[', pos);
  pos = InsertInt(size, pos);
  pos = InsertC(']', pos);
  return InsertBytes(reinterpret_cast<const byte*>(s), pos, size);
}


class ReferenceUpdater: public ObjectVisitor {
 public:
  ReferenceUpdater(HeapObject* obj, Serializer* serializer)
    : obj_address_(obj->address()),
      serializer_(serializer),
      reference_encoder_(serializer->reference_encoder_),
      offsets_(8),
      addresses_(8) {
  }

  virtual void VisitPointers(Object** start, Object** end) {
    for (Object** p = start; p < end; ++p) {
      if ((*p)->IsHeapObject()) {
        offsets_.Add(reinterpret_cast<Address>(p) - obj_address_);
        Address a = serializer_->GetSavedAddress(HeapObject::cast(*p));
        addresses_.Add(a);
      }
    }
  }

  virtual void VisitExternalReferences(Address* start, Address* end) {
    for (Address* p = start; p < end; ++p) {
      uint32_t code = reference_encoder_->Encode(*p);
      CHECK(*p == NULL ? code == 0 : code != 0);
      offsets_.Add(reinterpret_cast<Address>(p) - obj_address_);
      addresses_.Add(reinterpret_cast<Address>(code));
    }
  }

  virtual void VisitRuntimeEntry(RelocInfo* rinfo) {
    Address target = rinfo->target_address();
    uint32_t encoding = reference_encoder_->Encode(target);
    CHECK(target == NULL ? encoding == 0 : encoding != 0);
    offsets_.Add(reinterpret_cast<Address>(rinfo->pc()) - obj_address_);
    addresses_.Add(reinterpret_cast<Address>(encoding));
  }

  void Update(Address start_address) {
    for (int i = 0; i < offsets_.length(); i++) {
      Address* p = reinterpret_cast<Address*>(start_address + offsets_[i]);
      *p = addresses_[i];
    }
  }

 private:
  Address obj_address_;
  Serializer* serializer_;
  ExternalReferenceEncoder* reference_encoder_;
  List<int> offsets_;
  List<Address> addresses_;
};


// Helper functions for a map of encoded heap object addresses.
static uint32_t HeapObjectHash(HeapObject* key) {
  return reinterpret_cast<uint32_t>(key) >> 2;
}


static bool MatchHeapObject(void* key1, void* key2) {
  return key1 == key2;
}


Serializer::Serializer()
  : global_handles_(4),
    saved_addresses_(MatchHeapObject) {
  root_ = true;
  roots_ = 0;
  objects_ = 0;
  reference_encoder_ = NULL;
  writer_ = new SnapshotWriter();
  for (int i = 0; i <= LAST_SPACE; i++) {
    allocator_[i] = new SimulatedHeapSpace();
  }
}


Serializer::~Serializer() {
  for (int i = 0; i <= LAST_SPACE; i++) {
    delete allocator_[i];
  }
  if (reference_encoder_) delete reference_encoder_;
  delete writer_;
}


bool Serializer::serialization_enabled_ = true;


#ifdef DEBUG
static const int kMaxTagLength = 32;

void Serializer::Synchronize(const char* tag) {
  if (FLAG_debug_serialization) {
    int length = strlen(tag);
    ASSERT(length <= kMaxTagLength);
    writer_->PutC('S');
    writer_->PutInt(length);
    writer_->PutBytes(reinterpret_cast<const byte*>(tag), length);
  }
}
#endif


void Serializer::InitializeAllocators() {
  for (int i = 0; i <= LAST_SPACE; i++) {
    allocator_[i]->InitEmptyHeap(static_cast<AllocationSpace>(i));
  }
}


bool Serializer::IsVisited(HeapObject *obj) {
  HashMap::Entry* entry =
    saved_addresses_.Lookup(obj, HeapObjectHash(obj), false);
  return entry != NULL;
}


Address Serializer::GetSavedAddress(HeapObject *obj) {
  HashMap::Entry* entry
  = saved_addresses_.Lookup(obj, HeapObjectHash(obj), false);
  ASSERT(entry != NULL);
  return reinterpret_cast<Address>(entry->value);
}


void Serializer::SaveAddress(HeapObject* obj, Address addr) {
  HashMap::Entry* entry =
    saved_addresses_.Lookup(obj, HeapObjectHash(obj), true);
  entry->value = addr;
}


void Serializer::Serialize() {
  // No active threads.
  CHECK_EQ(NULL, ThreadState::FirstInUse());
  // No active or weak handles.
  CHECK(HandleScopeImplementer::instance()->Blocks()->is_empty());
  CHECK_EQ(0, GlobalHandles::NumberOfWeakHandles());
  // We need a counter function during serialization to resolve the
  // references to counters in the code on the heap.
  CHECK(StatsTable::HasCounterFunction());
  CHECK(enabled());
  InitializeAllocators();
  reference_encoder_ = new ExternalReferenceEncoder();
  PutHeader();
  Heap::IterateRoots(this);
  PutLog();
  PutContextStack();
  disable();
}


void Serializer::Finalize(char** str, int* len) {
  writer_->GetString(str, len);
}


// Serialize objects by writing them into the stream.

void Serializer::VisitPointers(Object** start, Object** end) {
  bool root = root_;
  root_ = false;
  for (Object** p = start; p < end; ++p) {
    bool serialized;
    Address a = Encode(*p, &serialized);
    if (root) {
      roots_++;
      // If the object was not just serialized,
      // write its encoded address instead.
      if (!serialized) PutEncodedAddress(a);
    }
  }
  root_ = root;
}


class GlobalHandlesRetriever: public ObjectVisitor {
 public:
  explicit GlobalHandlesRetriever(List<Object**>* handles)
  : global_handles_(handles) {}

  virtual void VisitPointers(Object** start, Object** end) {
    for (; start != end; ++start) {
      global_handles_->Add(start);
    }
  }

 private:
  List<Object**>* global_handles_;
};


void Serializer::PutFlags() {
  writer_->PutC('F');
  List<char*>* argv = FlagList::argv();
  writer_->PutInt(argv->length());
  writer_->PutC('[');
  for (int i = 0; i < argv->length(); i++) {
    if (i > 0) writer_->PutC('|');
    writer_->PutString((*argv)[i]);
    DeleteArray((*argv)[i]);
  }
  writer_->PutC(']');
  flags_end_ = writer_->length();
  delete argv;
}


void Serializer::PutHeader() {
  PutFlags();
  writer_->PutC('D');
#ifdef DEBUG
  writer_->PutC(FLAG_debug_serialization ? '1' : '0');
#else
  writer_->PutC('0');
#endif
  // Write sizes of paged memory spaces. Allocate extra space for the old
  // and code spaces, because objects in new space will be promoted to them.
  writer_->PutC('S');
  writer_->PutC('[');
  writer_->PutInt(Heap::old_pointer_space()->Size() +
                  Heap::new_space()->Size());
  writer_->PutC('|');
  writer_->PutInt(Heap::old_data_space()->Size() + Heap::new_space()->Size());
  writer_->PutC('|');
  writer_->PutInt(Heap::code_space()->Size() + Heap::new_space()->Size());
  writer_->PutC('|');
  writer_->PutInt(Heap::map_space()->Size());
  writer_->PutC(']');
  // Write global handles.
  writer_->PutC('G');
  writer_->PutC('[');
  GlobalHandlesRetriever ghr(&global_handles_);
  GlobalHandles::IterateRoots(&ghr);
  for (int i = 0; i < global_handles_.length(); i++) {
    writer_->PutC('N');
  }
  writer_->PutC(']');
}


void Serializer::PutLog() {
#ifdef ENABLE_LOGGING_AND_PROFILING
  if (FLAG_log_code) {
    Logger::TearDown();
    int pos = writer_->InsertC('L', flags_end_);
    bool exists;
    Vector<const char> log = ReadFile(FLAG_logfile, &exists);
    writer_->InsertString(log.start(), pos);
    log.Dispose();
  }
#endif