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// Copyright 2006-2008 the V8 project authors. All rights reserved.
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// 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 "v8.h"

#include "accessors.h"
#include "api.h"
#include "execution.h"
#include "global-handles.h"
#include "ic-inl.h"
#include "natives.h"
#include "platform.h"
#include "runtime.h"
#include "serialize.h"
#include "stub-cache.h"
#include "v8threads.h"
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#include "top.h"
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#include "bootstrapper.h"
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namespace v8 {
namespace internal {
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// -----------------------------------------------------------------------------
// Coding of external references.

// The encoding of an external reference. The type is in the high word.
// The id is in the low word.
static uint32_t EncodeExternal(TypeCode type, uint16_t id) {
  return static_cast<uint32_t>(type) << 16 | id;
}


static int* GetInternalPointer(StatsCounter* counter) {
  // All counters refer to dummy_counter, if deserializing happens without
  // setting up counters.
  static int dummy_counter = 0;
  return counter->Enabled() ? counter->GetInternalPointer() : &dummy_counter;
}


// ExternalReferenceTable is a helper class that defines the relationship
// between external references and their encodings. It is used to build
// hashmaps in ExternalReferenceEncoder and ExternalReferenceDecoder.
class ExternalReferenceTable {
 public:
  static ExternalReferenceTable* instance() {
    if (!instance_) instance_ = new ExternalReferenceTable();
    return instance_;
  }

  int size() const { return refs_.length(); }

  Address address(int i) { return refs_[i].address; }

  uint32_t code(int i) { return refs_[i].code; }

  const char* name(int i) { return refs_[i].name; }

  int max_id(int code) { return max_id_[code]; }

 private:
  static ExternalReferenceTable* instance_;

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  ExternalReferenceTable() : refs_(64) { PopulateTable(); }
  ~ExternalReferenceTable() { }
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  struct ExternalReferenceEntry {
    Address address;
    uint32_t code;
    const char* name;
  };

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  void PopulateTable();

  // For a few types of references, we can get their address from their id.
  void AddFromId(TypeCode type, uint16_t id, const char* name);

  // For other types of references, the caller will figure out the address.
  void Add(Address address, TypeCode type, uint16_t id, const char* name);
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  List<ExternalReferenceEntry> refs_;
  int max_id_[kTypeCodeCount];
};


ExternalReferenceTable* ExternalReferenceTable::instance_ = NULL;


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void ExternalReferenceTable::AddFromId(TypeCode type,
                                       uint16_t id,
                                       const char* name) {
  Address address;
  switch (type) {
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    case C_BUILTIN: {
      ExternalReference ref(static_cast<Builtins::CFunctionId>(id));
      address = ref.address();
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      break;
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    }
    case BUILTIN: {
      ExternalReference ref(static_cast<Builtins::Name>(id));
      address = ref.address();
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      break;
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    }
    case RUNTIME_FUNCTION: {
      ExternalReference ref(static_cast<Runtime::FunctionId>(id));
      address = ref.address();
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      break;
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    }
    case IC_UTILITY: {
      ExternalReference ref(IC_Utility(static_cast<IC::UtilityId>(id)));
      address = ref.address();
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      break;
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    }
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    default:
      UNREACHABLE();
      return;
  }
  Add(address, type, id, name);
}


void ExternalReferenceTable::Add(Address address,
                                 TypeCode type,
                                 uint16_t id,
                                 const char* name) {
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  ASSERT_NE(NULL, address);
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  ExternalReferenceEntry entry;
  entry.address = address;
  entry.code = EncodeExternal(type, id);
  entry.name = name;
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  ASSERT_NE(0, entry.code);
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  refs_.Add(entry);
  if (id > max_id_[type]) max_id_[type] = id;
}


void ExternalReferenceTable::PopulateTable() {
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  for (int type_code = 0; type_code < kTypeCodeCount; type_code++) {
    max_id_[type_code] = 0;
  }

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  // The following populates all of the different type of external references
  // into the ExternalReferenceTable.
  //
  // NOTE: This function was originally 100k of code.  It has since been
  // rewritten to be mostly table driven, as the callback macro style tends to
  // very easily cause code bloat.  Please be careful in the future when adding
  // new references.

  struct RefTableEntry {
    TypeCode type;
    uint16_t id;
    const char* name;
  };
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  static const RefTableEntry ref_table[] = {
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  // Builtins
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#define DEF_ENTRY_C(name, ignored) \
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  { C_BUILTIN, \
    Builtins::c_##name, \
    "Builtins::" #name },
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  BUILTIN_LIST_C(DEF_ENTRY_C)
#undef DEF_ENTRY_C

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#define DEF_ENTRY_C(name, ignored) \
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  { BUILTIN, \
    Builtins::name, \
    "Builtins::" #name },
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#define DEF_ENTRY_A(name, kind, state) DEF_ENTRY_C(name, ignored)
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  BUILTIN_LIST_C(DEF_ENTRY_C)
  BUILTIN_LIST_A(DEF_ENTRY_A)
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  BUILTIN_LIST_DEBUG_A(DEF_ENTRY_A)
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#undef DEF_ENTRY_C
#undef DEF_ENTRY_A

  // Runtime functions
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#define RUNTIME_ENTRY(name, nargs, ressize) \
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  { RUNTIME_FUNCTION, \
    Runtime::k##name, \
    "Runtime::" #name },
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  RUNTIME_FUNCTION_LIST(RUNTIME_ENTRY)
#undef RUNTIME_ENTRY

  // IC utilities
#define IC_ENTRY(name) \
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  { IC_UTILITY, \
    IC::k##name, \
    "IC::" #name },
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  IC_UTIL_LIST(IC_ENTRY)
#undef IC_ENTRY
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  };  // end of ref_table[].

  for (size_t i = 0; i < ARRAY_SIZE(ref_table); ++i) {
    AddFromId(ref_table[i].type, ref_table[i].id, ref_table[i].name);
  }
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#ifdef ENABLE_DEBUGGER_SUPPORT
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  // Debug addresses
  Add(Debug_Address(Debug::k_after_break_target_address).address(),
      DEBUG_ADDRESS,
      Debug::k_after_break_target_address << kDebugIdShift,
      "Debug::after_break_target_address()");
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  Add(Debug_Address(Debug::k_debug_break_slot_address).address(),
      DEBUG_ADDRESS,
      Debug::k_debug_break_slot_address << kDebugIdShift,
      "Debug::debug_break_slot_address()");
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  Add(Debug_Address(Debug::k_debug_break_return_address).address(),
      DEBUG_ADDRESS,
      Debug::k_debug_break_return_address << kDebugIdShift,
      "Debug::debug_break_return_address()");
  const char* debug_register_format = "Debug::register_address(%i)";
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  int dr_format_length = StrLength(debug_register_format);
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  for (int i = 0; i < kNumJSCallerSaved; ++i) {
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    Vector<char> name = Vector<char>::New(dr_format_length + 1);
    OS::SNPrintF(name, debug_register_format, i);
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    Add(Debug_Address(Debug::k_register_address, i).address(),
        DEBUG_ADDRESS,
        Debug::k_register_address << kDebugIdShift | i,
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        name.start());
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  }
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#endif
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  // Stat counters
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  struct StatsRefTableEntry {
    StatsCounter* counter;
    uint16_t id;
    const char* name;
  };

  static const StatsRefTableEntry stats_ref_table[] = {
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#define COUNTER_ENTRY(name, caption) \
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  { &Counters::name, \
    Counters::k_##name, \
    "Counters::" #name },
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  STATS_COUNTER_LIST_1(COUNTER_ENTRY)
  STATS_COUNTER_LIST_2(COUNTER_ENTRY)
#undef COUNTER_ENTRY
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  };  // end of stats_ref_table[].

  for (size_t i = 0; i < ARRAY_SIZE(stats_ref_table); ++i) {
    Add(reinterpret_cast<Address>(
            GetInternalPointer(stats_ref_table[i].counter)),
        STATS_COUNTER,
        stats_ref_table[i].id,
        stats_ref_table[i].name);
  }
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  // Top addresses
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  const char* top_address_format = "Top::%s";

  const char* AddressNames[] = {
#define C(name) #name,
    TOP_ADDRESS_LIST(C)
    TOP_ADDRESS_LIST_PROF(C)
    NULL
#undef C
  };

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  int top_format_length = StrLength(top_address_format) - 2;
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  for (uint16_t i = 0; i < Top::k_top_address_count; ++i) {
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    const char* address_name = AddressNames[i];
    Vector<char> name =
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        Vector<char>::New(top_format_length + StrLength(address_name) + 1);
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    const char* chars = name.start();
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    OS::SNPrintF(name, top_address_format, address_name);
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    Add(Top::get_address_from_id((Top::AddressId)i), TOP_ADDRESS, i, chars);
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  }

  // Extensions
  Add(FUNCTION_ADDR(GCExtension::GC), EXTENSION, 1,
      "GCExtension::GC");

  // 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
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  Add(ExternalReference::perform_gc_function().address(),
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      RUNTIME_ENTRY,
      1,
      "Runtime::PerformGC");
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  Add(ExternalReference::fill_heap_number_with_random_function().address(),
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      RUNTIME_ENTRY,
      2,
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      "V8::FillHeapNumberWithRandom");
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  Add(ExternalReference::random_uint32_function().address(),
      RUNTIME_ENTRY,
      3,
      "V8::Random");

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  // Miscellaneous
  Add(ExternalReference::the_hole_value_location().address(),
      UNCLASSIFIED,
      2,
      "Factory::the_hole_value().location()");
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  Add(ExternalReference::roots_address().address(),
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      UNCLASSIFIED,
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      3,
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      "Heap::roots_address()");
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  Add(ExternalReference::address_of_stack_limit().address(),
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      UNCLASSIFIED,
      4,
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      "StackGuard::address_of_jslimit()");
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  Add(ExternalReference::address_of_real_stack_limit().address(),
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      UNCLASSIFIED,
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      "StackGuard::address_of_real_jslimit()");
  Add(ExternalReference::address_of_regexp_stack_limit().address(),
      UNCLASSIFIED,
      6,
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      "RegExpStack::limit_address()");
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  Add(ExternalReference::address_of_regexp_stack_memory_address().address(),
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      UNCLASSIFIED,
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      7,
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      "RegExpStack::memory_address()");
  Add(ExternalReference::address_of_regexp_stack_memory_size().address(),
      UNCLASSIFIED,
      8,
      "RegExpStack::memory_size()");
  Add(ExternalReference::address_of_static_offsets_vector().address(),
      UNCLASSIFIED,
      9,
      "OffsetsVector::static_offsets_vector");
  Add(ExternalReference::new_space_start().address(),
      UNCLASSIFIED,
      10,
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      "Heap::NewSpaceStart()");
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  Add(ExternalReference::new_space_mask().address(),
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      UNCLASSIFIED,
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      11,
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      "Heap::NewSpaceMask()");
  Add(ExternalReference::heap_always_allocate_scope_depth().address(),
      UNCLASSIFIED,
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      12,
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      "Heap::always_allocate_scope_depth()");
  Add(ExternalReference::new_space_allocation_limit_address().address(),
      UNCLASSIFIED,
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      13,
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      "Heap::NewSpaceAllocationLimitAddress()");
  Add(ExternalReference::new_space_allocation_top_address().address(),
      UNCLASSIFIED,
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      14,
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      "Heap::NewSpaceAllocationTopAddress()");
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#ifdef ENABLE_DEBUGGER_SUPPORT
  Add(ExternalReference::debug_break().address(),
      UNCLASSIFIED,
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      15,
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      "Debug::Break()");
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  Add(ExternalReference::debug_step_in_fp_address().address(),
      UNCLASSIFIED,
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      16,
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      "Debug::step_in_fp_addr()");
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#endif
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  Add(ExternalReference::double_fp_operation(Token::ADD).address(),
      UNCLASSIFIED,
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      17,
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      "add_two_doubles");
  Add(ExternalReference::double_fp_operation(Token::SUB).address(),
      UNCLASSIFIED,
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      18,
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      "sub_two_doubles");
  Add(ExternalReference::double_fp_operation(Token::MUL).address(),
      UNCLASSIFIED,
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      19,
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      "mul_two_doubles");
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  Add(ExternalReference::double_fp_operation(Token::DIV).address(),
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      UNCLASSIFIED,
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      20,
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      "div_two_doubles");
  Add(ExternalReference::double_fp_operation(Token::MOD).address(),
      UNCLASSIFIED,
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      21,
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      "mod_two_doubles");
  Add(ExternalReference::compare_doubles().address(),
      UNCLASSIFIED,
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      22,
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      "compare_doubles");
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#ifndef V8_INTERPRETED_REGEXP
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  Add(ExternalReference::re_case_insensitive_compare_uc16().address(),
      UNCLASSIFIED,
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      23,
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      "NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16()");
  Add(ExternalReference::re_check_stack_guard_state().address(),
      UNCLASSIFIED,
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      24,
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      "RegExpMacroAssembler*::CheckStackGuardState()");
  Add(ExternalReference::re_grow_stack().address(),
      UNCLASSIFIED,
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      25,
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      "NativeRegExpMacroAssembler::GrowStack()");
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  Add(ExternalReference::re_word_character_map().address(),
      UNCLASSIFIED,
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      26,
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      "NativeRegExpMacroAssembler::word_character_map");
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#endif  // V8_INTERPRETED_REGEXP
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  // Keyed lookup cache.
  Add(ExternalReference::keyed_lookup_cache_keys().address(),
      UNCLASSIFIED,
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      27,
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      "KeyedLookupCache::keys()");
  Add(ExternalReference::keyed_lookup_cache_field_offsets().address(),
      UNCLASSIFIED,
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      28,
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      "KeyedLookupCache::field_offsets()");
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  Add(ExternalReference::transcendental_cache_array_address().address(),
      UNCLASSIFIED,
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      29,
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      "TranscendentalCache::caches()");
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}


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);
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  return entry == NULL
      ? -1
      : static_cast<int>(reinterpret_cast<intptr_t>(entry->value));
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}


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


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_);
}


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bool Serializer::serialization_enabled_ = false;
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bool Serializer::too_late_to_enable_now_ = false;
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ExternalReferenceDecoder* Deserializer::external_reference_decoder_ = NULL;
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Deserializer::Deserializer(SnapshotByteSource* source) : source_(source) {
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}


// This routine both allocates a new object, and also keeps
// track of where objects have been allocated so that we can
// fix back references when deserializing.
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Address Deserializer::Allocate(int space_index, Space* space, int size) {
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  Address address;
  if (!SpaceIsLarge(space_index)) {
    ASSERT(!SpaceIsPaged(space_index) ||
           size <= Page::kPageSize - Page::kObjectStartOffset);
    Object* new_allocation;
    if (space_index == NEW_SPACE) {
      new_allocation = reinterpret_cast<NewSpace*>(space)->AllocateRaw(size);
    } else {
      new_allocation = reinterpret_cast<PagedSpace*>(space)->AllocateRaw(size);
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    }
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    HeapObject* new_object = HeapObject::cast(new_allocation);
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    ASSERT(!new_object->IsFailure());
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    address = new_object->address();
    high_water_[space_index] = address + size;
  } else {
    ASSERT(SpaceIsLarge(space_index));
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    ASSERT(size > Page::kPageSize - Page::kObjectStartOffset);
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    LargeObjectSpace* lo_space = reinterpret_cast<LargeObjectSpace*>(space);
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    Object* new_allocation;
    if (space_index == kLargeData) {
      new_allocation = lo_space->AllocateRaw(size);
    } else if (space_index == kLargeFixedArray) {
      new_allocation = lo_space->AllocateRawFixedArray(size);
    } else {
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      ASSERT_EQ(kLargeCode, space_index);
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      new_allocation = lo_space->AllocateRawCode(size);
    }
    ASSERT(!new_allocation->IsFailure());
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    HeapObject* new_object = HeapObject::cast(new_allocation);
    // Record all large objects in the same space.
    address = new_object->address();
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    pages_[LO_SPACE].Add(address);
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  }
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  last_object_address_ = address;
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  return address;
}


// This returns the address of an object that has been described in the
// snapshot as being offset bytes back in a particular space.
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HeapObject* Deserializer::GetAddressFromEnd(int space) {
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  int offset = source_->GetInt();
  ASSERT(!SpaceIsLarge(space));
  offset <<= kObjectAlignmentBits;
  return HeapObject::FromAddress(high_water_[space] - offset);
}


// This returns the address of an object that has been described in the
// snapshot as being offset bytes into a particular space.
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HeapObject* Deserializer::GetAddressFromStart(int space) {
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  int offset = source_->GetInt();
  if (SpaceIsLarge(space)) {
    // Large spaces have one object per 'page'.
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    return HeapObject::FromAddress(pages_[LO_SPACE][offset]);
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  }
  offset <<= kObjectAlignmentBits;
  if (space == NEW_SPACE) {
    // New space has only one space - numbered 0.
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    return HeapObject::FromAddress(pages_[space][0] + offset);
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  }
  ASSERT(SpaceIsPaged(space));
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  int page_of_pointee = offset >> kPageSizeBits;
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  Address object_address = pages_[space][page_of_pointee] +
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                           (offset & Page::kPageAlignmentMask);
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  return HeapObject::FromAddress(object_address);
}


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void Deserializer::Deserialize() {
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  // Don't GC while deserializing - just expand the heap.
  AlwaysAllocateScope always_allocate;
  // Don't use the free lists while deserializing.
  LinearAllocationScope allocate_linearly;
  // No active threads.
  ASSERT_EQ(NULL, ThreadState::FirstInUse());
  // No active handles.
  ASSERT(HandleScopeImplementer::instance()->blocks()->is_empty());
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  // Make sure the entire partial snapshot cache is traversed, filling it with
  // valid object pointers.
  partial_snapshot_cache_length_ = kPartialSnapshotCacheCapacity;
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  ASSERT_EQ(NULL, external_reference_decoder_);
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  external_reference_decoder_ = new ExternalReferenceDecoder();
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  Heap::IterateStrongRoots(this, VISIT_ONLY_STRONG);
  Heap::IterateWeakRoots(this, VISIT_ALL);
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}


void Deserializer::DeserializePartial(Object** root) {
  // Don't GC while deserializing - just expand the heap.
  AlwaysAllocateScope always_allocate;
  // Don't use the free lists while deserializing.
  LinearAllocationScope allocate_linearly;
  if (external_reference_decoder_ == NULL) {
    external_reference_decoder_ = new ExternalReferenceDecoder();
  }
  VisitPointer(root);
}


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Deserializer::~Deserializer() {
  ASSERT(source_->AtEOF());
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  if (external_reference_decoder_ != NULL) {
    delete external_reference_decoder_;
    external_reference_decoder_ = NULL;
  }
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}


// This is called on the roots.  It is the driver of the deserialization
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// process.  It is also called on the body of each function.
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void Deserializer::VisitPointers(Object** start, Object** end) {
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  // The space must be new space.  Any other space would cause ReadChunk to try
  // to update the remembered using NULL as the address.
  ReadChunk(start, end, NEW_SPACE, NULL);
655 656 657 658 659 660 661 662 663
}


// This routine writes the new object into the pointer provided and then
// returns true if the new object was in young space and false otherwise.
// The reason for this strange interface is that otherwise the object is
// written very late, which means the ByteArray map is not set up by the
// time we need to use it to mark the space at the end of a page free (by
// making it into a byte array).
664 665 666
void Deserializer::ReadObject(int space_number,
                              Space* space,
                              Object** write_back) {
667
  int size = source_->GetInt() << kObjectAlignmentBits;
668
  Address address = Allocate(space_number, space, size);
669 670 671
  *write_back = HeapObject::FromAddress(address);
  Object** current = reinterpret_cast<Object**>(address);
  Object** limit = current + (size >> kPointerSizeLog2);
672 673 674
  if (FLAG_log_snapshot_positions) {
    LOG(SnapshotPositionEvent(address, source_->position()));
  }
675 676 677 678
  ReadChunk(current, limit, space_number, address);
}


679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702
// This macro is always used with a constant argument so it should all fold
// away to almost nothing in the generated code.  It might be nicer to do this
// with the ternary operator but there are type issues with that.
#define ASSIGN_DEST_SPACE(space_number)                                        \
  Space* dest_space;                                                           \
  if (space_number == NEW_SPACE) {                                             \
    dest_space = Heap::new_space();                                            \
  } else if (space_number == OLD_POINTER_SPACE) {                              \
    dest_space = Heap::old_pointer_space();                                    \
  } else if (space_number == OLD_DATA_SPACE) {                                 \
    dest_space = Heap::old_data_space();                                       \
  } else if (space_number == CODE_SPACE) {                                     \
    dest_space = Heap::code_space();                                           \
  } else if (space_number == MAP_SPACE) {                                      \
    dest_space = Heap::map_space();                                            \
  } else if (space_number == CELL_SPACE) {                                     \
    dest_space = Heap::cell_space();                                           \
  } else {                                                                     \
    ASSERT(space_number >= LO_SPACE);                                          \
    dest_space = Heap::lo_space();                                             \
  }


static const int kUnknownOffsetFromStart = -1;
703 704


705 706
void Deserializer::ReadChunk(Object** current,
                             Object** limit,
707
                             int source_space,
708
                             Address address) {
709
  while (current < limit) {
710
    int data = source_->Get();
711
    switch (data) {
712 713 714 715
#define CASE_STATEMENT(where, how, within, space_number)                       \
      case where + how + within + space_number:                                \
      ASSERT((where & ~kPointedToMask) == 0);                                  \
      ASSERT((how & ~kHowToCodeMask) == 0);                                    \
716
      ASSERT((within & ~kWhereToPointMask) == 0);                              \
717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834
      ASSERT((space_number & ~kSpaceMask) == 0);

#define CASE_BODY(where, how, within, space_number_if_any, offset_from_start)  \
      {                                                                        \
        bool emit_write_barrier = false;                                       \
        bool current_was_incremented = false;                                  \
        int space_number =  space_number_if_any == kAnyOldSpace ?              \
                            (data & kSpaceMask) : space_number_if_any;         \
        if (where == kNewObject && how == kPlain && within == kStartOfObject) {\
          ASSIGN_DEST_SPACE(space_number)                                      \
          ReadObject(space_number, dest_space, current);                       \
          emit_write_barrier =                                                 \
            (space_number == NEW_SPACE && source_space != NEW_SPACE);          \
        } else {                                                               \
          Object* new_object = NULL;  /* May not be a real Object pointer. */  \
          if (where == kNewObject) {                                           \
            ASSIGN_DEST_SPACE(space_number)                                    \
            ReadObject(space_number, dest_space, &new_object);                 \
          } else if (where == kRootArray) {                                    \
            int root_id = source_->GetInt();                                   \
            new_object = Heap::roots_address()[root_id];                       \
          } else if (where == kPartialSnapshotCache) {                         \
            int cache_index = source_->GetInt();                               \
            new_object = partial_snapshot_cache_[cache_index];                 \
          } else if (where == kExternalReference) {                            \
            int reference_id = source_->GetInt();                              \
            Address address =                                                  \
                external_reference_decoder_->Decode(reference_id);             \
            new_object = reinterpret_cast<Object*>(address);                   \
          } else if (where == kBackref) {                                      \
            emit_write_barrier =                                               \
              (space_number == NEW_SPACE && source_space != NEW_SPACE);        \
            new_object = GetAddressFromEnd(data & kSpaceMask);                 \
          } else {                                                             \
            ASSERT(where == kFromStart);                                       \
            if (offset_from_start == kUnknownOffsetFromStart) {                \
              emit_write_barrier =                                             \
                (space_number == NEW_SPACE && source_space != NEW_SPACE);      \
              new_object = GetAddressFromStart(data & kSpaceMask);             \
            } else {                                                           \
              Address object_address = pages_[space_number][0] +               \
                  (offset_from_start << kObjectAlignmentBits);                 \
              new_object = HeapObject::FromAddress(object_address);            \
            }                                                                  \
          }                                                                    \
          if (within == kFirstInstruction) {                                   \
            Code* new_code_object = reinterpret_cast<Code*>(new_object);       \
            new_object = reinterpret_cast<Object*>(                            \
                new_code_object->instruction_start());                         \
          }                                                                    \
          if (how == kFromCode) {                                              \
            Address location_of_branch_data =                                  \
                reinterpret_cast<Address>(current);                            \
            Assembler::set_target_at(location_of_branch_data,                  \
                                     reinterpret_cast<Address>(new_object));   \
            if (within == kFirstInstruction) {                                 \
              location_of_branch_data += Assembler::kCallTargetSize;           \
              current = reinterpret_cast<Object**>(location_of_branch_data);   \
              current_was_incremented = true;                                  \
            }                                                                  \
          } else {                                                             \
            *current = new_object;                                             \
          }                                                                    \
        }                                                                      \
        if (emit_write_barrier) {                                              \
          Heap::RecordWrite(address, static_cast<int>(                         \
              reinterpret_cast<Address>(current) - address));                  \
        }                                                                      \
        if (!current_was_incremented) {                                        \
          current++;   /* Increment current if it wasn't done above. */        \
        }                                                                      \
        break;                                                                 \
      }                                                                        \

// This generates a case and a body for each space.  The large object spaces are
// very rare in snapshots so they are grouped in one body.
#define ONE_PER_SPACE(where, how, within)                                      \
  CASE_STATEMENT(where, how, within, NEW_SPACE)                                \
  CASE_BODY(where, how, within, NEW_SPACE, kUnknownOffsetFromStart)            \
  CASE_STATEMENT(where, how, within, OLD_DATA_SPACE)                           \
  CASE_BODY(where, how, within, OLD_DATA_SPACE, kUnknownOffsetFromStart)       \
  CASE_STATEMENT(where, how, within, OLD_POINTER_SPACE)                        \
  CASE_BODY(where, how, within, OLD_POINTER_SPACE, kUnknownOffsetFromStart)    \
  CASE_STATEMENT(where, how, within, CODE_SPACE)                               \
  CASE_BODY(where, how, within, CODE_SPACE, kUnknownOffsetFromStart)           \
  CASE_STATEMENT(where, how, within, CELL_SPACE)                               \
  CASE_BODY(where, how, within, CELL_SPACE, kUnknownOffsetFromStart)           \
  CASE_STATEMENT(where, how, within, MAP_SPACE)                                \
  CASE_BODY(where, how, within, MAP_SPACE, kUnknownOffsetFromStart)            \
  CASE_STATEMENT(where, how, within, kLargeData)                               \
  CASE_STATEMENT(where, how, within, kLargeCode)                               \
  CASE_STATEMENT(where, how, within, kLargeFixedArray)                         \
  CASE_BODY(where, how, within, kAnyOldSpace, kUnknownOffsetFromStart)

// This generates a case and a body for the new space (which has to do extra
// write barrier handling) and handles the other spaces with 8 fall-through
// cases and one body.
#define ALL_SPACES(where, how, within)                                         \
  CASE_STATEMENT(where, how, within, NEW_SPACE)                                \
  CASE_BODY(where, how, within, NEW_SPACE, kUnknownOffsetFromStart)            \
  CASE_STATEMENT(where, how, within, OLD_DATA_SPACE)                           \
  CASE_STATEMENT(where, how, within, OLD_POINTER_SPACE)                        \
  CASE_STATEMENT(where, how, within, CODE_SPACE)                               \
  CASE_STATEMENT(where, how, within, CELL_SPACE)                               \
  CASE_STATEMENT(where, how, within, MAP_SPACE)                                \
  CASE_STATEMENT(where, how, within, kLargeData)                               \
  CASE_STATEMENT(where, how, within, kLargeCode)                               \
  CASE_STATEMENT(where, how, within, kLargeFixedArray)                         \
  CASE_BODY(where, how, within, kAnyOldSpace, kUnknownOffsetFromStart)

#define EMIT_COMMON_REFERENCE_PATTERNS(pseudo_space_number,                    \
                                       space_number,                           \
                                       offset_from_start)                      \
  CASE_STATEMENT(kFromStart, kPlain, kStartOfObject, pseudo_space_number)      \
  CASE_BODY(kFromStart, kPlain, kStartOfObject, space_number, offset_from_start)

      // We generate 15 cases and bodies that process special tags that combine
      // the raw data tag and the length into one byte.
835
#define RAW_CASE(index, size)                                      \
836
      case kRawData + index: {                                     \
837 838 839 840 841 842 843
        byte* raw_data_out = reinterpret_cast<byte*>(current);     \
        source_->CopyRaw(raw_data_out, size);                      \
        current = reinterpret_cast<Object**>(raw_data_out + size); \
        break;                                                     \
      }
      COMMON_RAW_LENGTHS(RAW_CASE)
#undef RAW_CASE
844 845 846 847

      // Deserialize a chunk of raw data that doesn't have one of the popular
      // lengths.
      case kRawData: {
848 849
        int size = source_->GetInt();
        byte* raw_data_out = reinterpret_cast<byte*>(current);
850 851
        source_->CopyRaw(raw_data_out, size);
        current = reinterpret_cast<Object**>(raw_data_out + size);
852 853
        break;
      }
854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914

      // Deserialize a new object and write a pointer to it to the current
      // object.
      ONE_PER_SPACE(kNewObject, kPlain, kStartOfObject)
      // Deserialize a new code object and write a pointer to its first
      // instruction to the current code object.
      ONE_PER_SPACE(kNewObject, kFromCode, kFirstInstruction)
      // Find a recently deserialized object using its offset from the current
      // allocation point and write a pointer to it to the current object.
      ALL_SPACES(kBackref, kPlain, kStartOfObject)
      // Find a recently deserialized code object using its offset from the
      // current allocation point and write a pointer to its first instruction
      // to the current code object.
      ALL_SPACES(kBackref, kFromCode, kFirstInstruction)
      // Find an already deserialized object using its offset from the start
      // and write a pointer to it to the current object.
      ALL_SPACES(kFromStart, kPlain, kStartOfObject)
      // Find an already deserialized code object using its offset from the
      // start and write a pointer to its first instruction to the current code
      // object.
      ALL_SPACES(kFromStart, kFromCode, kFirstInstruction)
      // Find an already deserialized object at one of the predetermined popular
      // offsets from the start and write a pointer to it in the current object.
      COMMON_REFERENCE_PATTERNS(EMIT_COMMON_REFERENCE_PATTERNS)
      // 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, kUnknownOffsetFromStart)
      // 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,
                kUnknownOffsetFromStart)
      // 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,
                kUnknownOffsetFromStart)
      // 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,
                kUnknownOffsetFromStart)

#undef CASE_STATEMENT
#undef CASE_BODY
#undef ONE_PER_SPACE
#undef ALL_SPACES
#undef EMIT_COMMON_REFERENCE_PATTERNS
#undef ASSIGN_DEST_SPACE

      case kNewPage: {
915 916
        int space = source_->Get();
        pages_[space].Add(last_object_address_);
917 918 919
        if (space == CODE_SPACE) {
          CPU::FlushICache(last_object_address_, Page::kPageSize);
        }
920 921
        break;
      }
922 923

      case kNativesStringResource: {
924 925 926 927 928 929 930
        int index = source_->Get();
        Vector<const char> source_vector = Natives::GetScriptSource(index);
        NativesExternalStringResource* resource =
            new NativesExternalStringResource(source_vector.start());
        *current++ = reinterpret_cast<Object*>(resource);
        break;
      }
931 932

      case kSynchronize: {
933 934 935 936
        // If we get here then that indicates that you have a mismatch between
        // the number of GC roots when serializing and deserializing.
        UNREACHABLE();
      }
937

938 939 940 941
      default:
        UNREACHABLE();
    }
  }
942
  ASSERT_EQ(current, limit);
943 944 945 946 947 948
}


void SnapshotByteSink::PutInt(uintptr_t integer, const char* description) {
  const int max_shift = ((kPointerSize * kBitsPerByte) / 7) * 7;
  for (int shift = max_shift; shift > 0; shift -= 7) {
949
    if (integer >= static_cast<uintptr_t>(1u) << shift) {
950
      Put((static_cast<int>((integer >> shift)) & 0x7f) | 0x80, "IntPart");
951 952
    }
  }
953
  PutSection(static_cast<int>(integer & 0x7f), "IntLastPart");
954 955 956 957
}

#ifdef DEBUG

958
void Deserializer::Synchronize(const char* tag) {
959 960 961
  int data = source_->Get();
  // If this assert fails then that indicates that you have a mismatch between
  // the number of GC roots when serializing and deserializing.
962
  ASSERT_EQ(kSynchronize, data);
963 964 965 966 967 968 969 970 971 972 973 974 975
  do {
    int character = source_->Get();
    if (character == 0) break;
    if (FLAG_debug_serialization) {
      PrintF("%c", character);
    }
  } while (true);
  if (FLAG_debug_serialization) {
    PrintF("\n");
  }
}


976
void Serializer::Synchronize(const char* tag) {
977
  sink_->Put(kSynchronize, tag);
978 979 980
  int character;
  do {
    character = *tag++;
981
    sink_->PutSection(character, "TagCharacter");
982 983 984 985 986
  } while (character != 0);
}

#endif

987
Serializer::Serializer(SnapshotByteSink* sink)
988 989
    : sink_(sink),
      current_root_index_(0),
990
      external_reference_encoder_(new ExternalReferenceEncoder),
991
      large_object_total_(0) {
992 993 994 995 996 997
  for (int i = 0; i <= LAST_SPACE; i++) {
    fullness_[i] = 0;
  }
}


998 999 1000 1001 1002
Serializer::~Serializer() {
  delete external_reference_encoder_;
}


1003
void StartupSerializer::SerializeStrongReferences() {
1004 1005 1006 1007 1008
  // No active threads.
  CHECK_EQ(NULL, ThreadState::FirstInUse());
  // No active or weak handles.
  CHECK(HandleScopeImplementer::instance()->blocks()->is_empty());
  CHECK_EQ(0, GlobalHandles::NumberOfWeakHandles());
1009 1010 1011 1012 1013 1014
  // We don't support serializing installed extensions.
  for (RegisteredExtension* ext = RegisteredExtension::first_extension();
       ext != NULL;
       ext = ext->next()) {
    CHECK_NE(v8::INSTALLED, ext->state());
  }
1015
  Heap::IterateStrongRoots(this, VISIT_ONLY_STRONG);
1016 1017 1018
}


1019
void PartialSerializer::Serialize(Object** object) {
1020
  this->VisitPointer(object);
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032

  // After we have done the partial serialization the partial snapshot cache
  // will contain some references needed to decode the partial snapshot.  We
  // fill it up with undefineds so it has a predictable length so the
  // deserialization code doesn't need to know the length.
  for (int index = partial_snapshot_cache_length_;
       index < kPartialSnapshotCacheCapacity;
       index++) {
    partial_snapshot_cache_[index] = Heap::undefined_value();
    startup_serializer_->VisitPointer(&partial_snapshot_cache_[index]);
  }
  partial_snapshot_cache_length_ = kPartialSnapshotCacheCapacity;
1033 1034 1035
}


1036
void Serializer::VisitPointers(Object** start, Object** end) {
1037
  for (Object** current = start; current < end; current++) {
1038
    if ((*current)->IsSmi()) {
1039
      sink_->Put(kRawData, "RawData");
1040 1041 1042 1043 1044
      sink_->PutInt(kPointerSize, "length");
      for (int i = 0; i < kPointerSize; i++) {
        sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
      }
    } else {
1045
      SerializeObject(*current, kPlain, kStartOfObject);
1046
    }
1047 1048 1049 1050
  }
}


1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
Object* SerializerDeserializer::partial_snapshot_cache_[
    kPartialSnapshotCacheCapacity];
int SerializerDeserializer::partial_snapshot_cache_length_ = 0;


// This ensures that the partial snapshot cache keeps things alive during GC and
// tracks their movement.  When it is called during serialization of the startup
// snapshot the partial snapshot is empty, so nothing happens.  When the partial
// (context) snapshot is created, this array is populated with the pointers that
// the partial snapshot will need. As that happens we emit serialized objects to
// the startup snapshot that correspond to the elements of this cache array.  On
// deserialization we therefore need to visit the cache array.  This fills it up
// with pointers to deserialized objects.
1064
void SerializerDeserializer::Iterate(ObjectVisitor* visitor) {
1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
  visitor->VisitPointers(
      &partial_snapshot_cache_[0],
      &partial_snapshot_cache_[partial_snapshot_cache_length_]);
}


// When deserializing we need to set the size of the snapshot cache.  This means
// the root iteration code (above) will iterate over array elements, writing the
// references to deserialized objects in them.
void SerializerDeserializer::SetSnapshotCacheSize(int size) {
  partial_snapshot_cache_length_ = size;
}


int PartialSerializer::PartialSnapshotCacheIndex(HeapObject* heap_object) {
  for (int i = 0; i < partial_snapshot_cache_length_; i++) {
    Object* entry = partial_snapshot_cache_[i];
    if (entry == heap_object) return i;
  }
1084

1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
  // We didn't find the object in the cache.  So we add it to the cache and
  // then visit the pointer so that it becomes part of the startup snapshot
  // and we can refer to it from the partial snapshot.
  int length = partial_snapshot_cache_length_;
  CHECK(length < kPartialSnapshotCacheCapacity);
  partial_snapshot_cache_[length] = heap_object;
  startup_serializer_->VisitPointer(&partial_snapshot_cache_[length]);
  // We don't recurse from the startup snapshot generator into the partial
  // snapshot generator.
  ASSERT(length == partial_snapshot_cache_length_);
  return partial_snapshot_cache_length_++;
}


int PartialSerializer::RootIndex(HeapObject* heap_object) {
1100 1101 1102 1103 1104 1105 1106 1107
  for (int i = 0; i < Heap::kRootListLength; i++) {
    Object* root = Heap::roots_address()[i];
    if (root == heap_object) return i;
  }
  return kInvalidRootIndex;
}


1108 1109 1110 1111 1112 1113 1114
// 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::SerializeReferenceToPreviousObject(
    int space,
    int address,
1115 1116
    HowToCode how_to_code,
    WhereToPoint where_to_point) {
1117 1118 1119 1120 1121 1122 1123 1124 1125
  int offset = CurrentAllocationAddress(space) - address;
  bool from_start = true;
  if (SpaceIsPaged(space)) {
    // For paged space it is simple to encode back from current allocation if
    // the object is on the same page as the current allocation pointer.
    if ((CurrentAllocationAddress(space) >> kPageSizeBits) ==
        (address >> kPageSizeBits)) {
      from_start = false;
      address = offset;
1126
    }
1127 1128 1129 1130 1131
  } else if (space == NEW_SPACE) {
    // For new space it is always simple to encode back from current allocation.
    if (offset < address) {
      from_start = false;
      address = offset;
1132
    }
1133 1134 1135 1136
  }
  // If we are actually dealing with real offsets (and not a numbering of
  // all objects) then we should shift out the bits that are always 0.
  if (!SpaceIsLarge(space)) address >>= kObjectAlignmentBits;
1137 1138 1139 1140 1141 1142 1143 1144
  if (from_start) {
#define COMMON_REFS_CASE(pseudo_space, actual_space, offset)                   \
    if (space == actual_space && address == offset &&                          \
        how_to_code == kPlain && where_to_point == kStartOfObject) {           \
      sink_->Put(kFromStart + how_to_code + where_to_point +                   \
                 pseudo_space, "RefSer");                                      \
    } else  /* NOLINT */
    COMMON_REFERENCE_PATTERNS(COMMON_REFS_CASE)
1145
#undef COMMON_REFS_CASE
1146 1147
    {  /* NOLINT */
      sink_->Put(kFromStart + how_to_code + where_to_point + space, "RefSer");
1148
      sink_->PutInt(address, "address");
1149
    }
1150 1151 1152
  } else {
    sink_->Put(kBackref + how_to_code + where_to_point + space, "BackRefSer");
    sink_->PutInt(address, "address");
1153 1154 1155 1156 1157 1158
  }
}


void StartupSerializer::SerializeObject(
    Object* o,
1159 1160
    HowToCode how_to_code,
    WhereToPoint where_to_point) {
1161 1162 1163 1164 1165 1166 1167 1168
  CHECK(o->IsHeapObject());
  HeapObject* heap_object = HeapObject::cast(o);

  if (address_mapper_.IsMapped(heap_object)) {
    int space = SpaceOfAlreadySerializedObject(heap_object);
    int address = address_mapper_.MappedTo(heap_object);
    SerializeReferenceToPreviousObject(space,
                                       address,
1169 1170
                                       how_to_code,
                                       where_to_point);
1171 1172 1173 1174 1175
  } else {
    // Object has not yet been serialized.  Serialize it here.
    ObjectSerializer object_serializer(this,
                                       heap_object,
                                       sink_,
1176 1177
                                       how_to_code,
                                       where_to_point);
1178 1179 1180 1181 1182 1183 1184 1185 1186
    object_serializer.Serialize();
  }
}


void StartupSerializer::SerializeWeakReferences() {
  for (int i = partial_snapshot_cache_length_;
       i < kPartialSnapshotCacheCapacity;
       i++) {
1187
    sink_->Put(kRootArray + kPlain + kStartOfObject, "RootSerialization");
1188 1189 1190 1191 1192 1193 1194 1195
    sink_->PutInt(Heap::kUndefinedValueRootIndex, "root_index");
  }
  Heap::IterateWeakRoots(this, VISIT_ALL);
}


void PartialSerializer::SerializeObject(
    Object* o,
1196 1197
    HowToCode how_to_code,
    WhereToPoint where_to_point) {
1198 1199 1200 1201 1202
  CHECK(o->IsHeapObject());
  HeapObject* heap_object = HeapObject::cast(o);

  int root_index;
  if ((root_index = RootIndex(heap_object)) != kInvalidRootIndex) {
1203
    sink_->Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
1204 1205 1206 1207 1208 1209
    sink_->PutInt(root_index, "root_index");
    return;
  }

  if (ShouldBeInThePartialSnapshotCache(heap_object)) {
    int cache_index = PartialSnapshotCacheIndex(heap_object);
1210 1211
    sink_->Put(kPartialSnapshotCache + how_to_code + where_to_point,
               "PartialSnapshotCache");
1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228
    sink_->PutInt(cache_index, "partial_snapshot_cache_index");
    return;
  }

  // Pointers from the partial snapshot to the objects in the startup snapshot
  // should go through the root array or through the partial snapshot cache.
  // If this is not the case you may have to add something to the root array.
  ASSERT(!startup_serializer_->address_mapper()->IsMapped(heap_object));
  // All the symbols that the partial snapshot needs should be either in the
  // root table or in the partial snapshot cache.
  ASSERT(!heap_object->IsSymbol());

  if (address_mapper_.IsMapped(heap_object)) {
    int space = SpaceOfAlreadySerializedObject(heap_object);
    int address = address_mapper_.MappedTo(heap_object);
    SerializeReferenceToPreviousObject(space,
                                       address,
1229 1230
                                       how_to_code,
                                       where_to_point);
1231
  } else {
1232 1233 1234 1235
    // Object has not yet been serialized.  Serialize it here.
    ObjectSerializer serializer(this,
                                heap_object,
                                sink_,
1236 1237
                                how_to_code,
                                where_to_point);
1238
    serializer.Serialize();
1239 1240 1241 1242
  }
}


1243 1244
void Serializer::ObjectSerializer::Serialize() {
  int space = Serializer::SpaceOfObject(object_);
1245 1246
  int size = object_->Size();

1247 1248
  sink_->Put(kNewObject + reference_representation_ + space,
             "ObjectSerialization");
1249 1250
  sink_->PutInt(size >> kObjectAlignmentBits, "Size in words");

1251 1252
  LOG(SnapshotPositionEvent(object_->address(), sink_->Position()));

1253
  // Mark this object as already serialized.
1254
  bool start_new_page;
1255 1256
  int offset = serializer_->Allocate(space, size, &start_new_page);
  serializer_->address_mapper()->AddMapping(object_, offset);
1257
  if (start_new_page) {
1258
    sink_->Put(kNewPage, "NewPage");
1259 1260
    sink_->PutSection(space, "NewPageSpace");
  }
1261 1262

  // Serialize the map (first word of the object).
1263
  serializer_->SerializeObject(object_->map(), kPlain, kStartOfObject);
1264 1265

  // Serialize the rest of the object.
1266
  CHECK_EQ(0, bytes_processed_so_far_);
1267
  bytes_processed_so_far_ = kPointerSize;
1268
  object_->IterateBody(object_->map()->instance_type(), size, this);
1269 1270 1271 1272
  OutputRawData(object_->address() + size);
}


1273 1274
void Serializer::ObjectSerializer::VisitPointers(Object** start,
                                                 Object** end) {
1275 1276 1277
  Object** current = start;
  while (current < end) {
    while (current < end && (*current)->IsSmi()) current++;
1278
    if (current < end) OutputRawData(reinterpret_cast<Address>(current));
1279 1280

    while (current < end && !(*current)->IsSmi()) {
1281
      serializer_->SerializeObject(*current, kPlain, kStartOfObject);
1282 1283 1284
      bytes_processed_so_far_ += kPointerSize;
      current++;
    }
1285 1286 1287 1288
  }
}


1289 1290
void Serializer::ObjectSerializer::VisitExternalReferences(Address* start,
                                                           Address* end) {
1291 1292 1293 1294
  Address references_start = reinterpret_cast<Address>(start);
  OutputRawData(references_start);

  for (Address* current = start; current < end; current++) {
1295
    sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
1296 1297 1298
    int reference_id = serializer_->EncodeExternalReference(*current);
    sink_->PutInt(reference_id, "reference id");
  }
1299
  bytes_processed_so_far_ += static_cast<int>((end - start) * kPointerSize);
1300 1301 1302
}


1303
void Serializer::ObjectSerializer::VisitRuntimeEntry(RelocInfo* rinfo) {
1304 1305 1306 1307 1308
  Address target_start = rinfo->target_address_address();
  OutputRawData(target_start);
  Address target = rinfo->target_address();
  uint32_t encoding = serializer_->EncodeExternalReference(target);
  CHECK(target == NULL ? encoding == 0 : encoding != 0);
1309 1310 1311 1312 1313 1314 1315 1316
  int representation;
  // Can't use a ternary operator because of gcc.
  if (rinfo->IsCodedSpecially()) {
    representation = kStartOfObject + kFromCode;
  } else {
    representation = kStartOfObject + kPlain;
  }
  sink_->Put(kExternalReference + representation, "ExternalReference");
1317
  sink_->PutInt(encoding, "reference id");
1318
  bytes_processed_so_far_ += rinfo->target_address_size();
1319 1320 1321
}


1322 1323
void Serializer::ObjectSerializer::VisitCodeTarget(RelocInfo* rinfo) {
  CHECK(RelocInfo::IsCodeTarget(rinfo->rmode()));
1324 1325 1326
  Address target_start = rinfo->target_address_address();
  OutputRawData(target_start);
  Code* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
1327
  serializer_->SerializeObject(target, kFromCode, kFirstInstruction);
1328
  bytes_processed_so_far_ += rinfo->target_address_size();
1329 1330 1331
}


1332
void Serializer::ObjectSerializer::VisitExternalAsciiString(
1333 1334 1335 1336
    v8::String::ExternalAsciiStringResource** resource_pointer) {
  Address references_start = reinterpret_cast<Address>(resource_pointer);
  OutputRawData(references_start);
  for (int i = 0; i < Natives::GetBuiltinsCount(); i++) {
1337
    Object* source = Heap::natives_source_cache()->get(i);
1338
    if (!source->IsUndefined()) {
1339
      ExternalAsciiString* string = ExternalAsciiString::cast(source);
1340 1341 1342
      typedef v8::String::ExternalAsciiStringResource Resource;
      Resource* resource = string->resource();
      if (resource == *resource_pointer) {
1343
        sink_->Put(kNativesStringResource, "NativesStringResource");
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355
        sink_->PutSection(i, "NativesStringResourceEnd");
        bytes_processed_so_far_ += sizeof(resource);
        return;
      }
    }
  }
  // One of the strings in the natives cache should match the resource.  We
  // can't serialize any other kinds of external strings.
  UNREACHABLE();
}


1356
void Serializer::ObjectSerializer::OutputRawData(Address up_to) {
1357
  Address object_start = object_->address();
1358
  int up_to_offset = static_cast<int>(up_to - object_start);
1359
  int skipped = up_to_offset - bytes_processed_so_far_;
1360 1361
  // 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.
1362 1363
  ASSERT(skipped >= 0);
  if (skipped != 0) {
1364 1365 1366
    Address base = object_start + bytes_processed_so_far_;
#define RAW_CASE(index, length)                                                \
    if (skipped == length) {                                                   \
1367
      sink_->PutSection(kRawData + index, "RawDataFixed");                     \
1368 1369 1370 1371
    } else  /* NOLINT */
    COMMON_RAW_LENGTHS(RAW_CASE)
#undef RAW_CASE
    {  /* NOLINT */
1372
      sink_->Put(kRawData, "RawData");
1373 1374
      sink_->PutInt(skipped, "length");
    }
1375
    for (int i = 0; i < skipped; i++) {
1376 1377
      unsigned int data = base[i];
      sink_->PutSection(data, "Byte");
1378
    }
1379
    bytes_processed_so_far_ += skipped;
1380 1381 1382 1383
  }
}


1384
int Serializer::SpaceOfObject(HeapObject* object) {
1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404
  for (int i = FIRST_SPACE; i <= LAST_SPACE; i++) {
    AllocationSpace s = static_cast<AllocationSpace>(i);
    if (Heap::InSpace(object, s)) {
      if (i == LO_SPACE) {
        if (object->IsCode()) {
          return kLargeCode;
        } else if (object->IsFixedArray()) {
          return kLargeFixedArray;
        } else {
          return kLargeData;
        }
      }
      return i;
    }
  }
  UNREACHABLE();
  return 0;
}


1405
int Serializer::SpaceOfAlreadySerializedObject(HeapObject* object) {
1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416
  for (int i = FIRST_SPACE; i <= LAST_SPACE; i++) {
    AllocationSpace s = static_cast<AllocationSpace>(i);
    if (Heap::InSpace(object, s)) {
      return i;
    }
  }
  UNREACHABLE();
  return 0;
}


1417 1418
int Serializer::Allocate(int space, int size, bool* new_page) {
  CHECK(space >= 0 && space < kNumberOfSpaces);
1419 1420 1421
  if (SpaceIsLarge(space)) {
    // In large object space we merely number the objects instead of trying to
    // determine some sort of address.
1422
    *new_page = true;
1423
    large_object_total_ += size;
1424 1425
    return fullness_[LO_SPACE]++;
  }
1426 1427 1428 1429
  *new_page = false;
  if (fullness_[space] == 0) {
    *new_page = true;
  }
1430 1431 1432 1433 1434 1435 1436
  if (SpaceIsPaged(space)) {
    // Paged spaces are a little special.  We encode their addresses as if the
    // pages were all contiguous and each page were filled up in the range
    // 0 - Page::kObjectAreaSize.  In practice the pages may not be contiguous
    // and allocation does not start at offset 0 in the page, but this scheme
    // means the deserializer can get the page number quickly by shifting the
    // serialized address.
1437
    CHECK(IsPowerOf2(Page::kPageSize));
1438
    int used_in_this_page = (fullness_[space] & (Page::kPageSize - 1));
1439
    CHECK(size <= Page::kObjectAreaSize);
1440
    if (used_in_this_page + size > Page::kObjectAreaSize) {
1441
      *new_page = true;
1442 1443 1444 1445 1446 1447 1448 1449 1450
      fullness_[space] = RoundUp(fullness_[space], Page::kPageSize);
    }
  }
  int allocation_address = fullness_[space];
  fullness_[space] = allocation_address + size;
  return allocation_address;
}


1451
} }  // namespace v8::internal