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v8/src/serialize.cc
erik.corry@gmail.com a02dbe4258 Revert 10413-10416 initial memory use reduction due to 
test failures.
Review URL: http://codereview.chromium.org/9178014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2012-01-17 13:13:55 +00:00

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// Copyright 2011 the V8 project authors. All rights reserved.
// 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 "bootstrapper.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"
namespace v8 {
namespace internal {
// -----------------------------------------------------------------------------
// 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* ExternalReferenceTable::instance(Isolate* isolate) {
ExternalReferenceTable* external_reference_table =
isolate->external_reference_table();
if (external_reference_table == NULL) {
external_reference_table = new ExternalReferenceTable(isolate);
isolate->set_external_reference_table(external_reference_table);
}
return external_reference_table;
}
void ExternalReferenceTable::AddFromId(TypeCode type,
uint16_t id,
const char* name,
Isolate* isolate) {
Address address;
switch (type) {
case C_BUILTIN: {
ExternalReference ref(static_cast<Builtins::CFunctionId>(id), isolate);
address = ref.address();
break;
}
case BUILTIN: {
ExternalReference ref(static_cast<Builtins::Name>(id), isolate);
address = ref.address();
break;
}
case RUNTIME_FUNCTION: {
ExternalReference ref(static_cast<Runtime::FunctionId>(id), isolate);
address = ref.address();
break;
}
case IC_UTILITY: {
ExternalReference ref(IC_Utility(static_cast<IC::UtilityId>(id)),
isolate);
address = ref.address();
break;
}
default:
UNREACHABLE();
return;
}
Add(address, type, id, name);
}
void ExternalReferenceTable::Add(Address address,
TypeCode type,
uint16_t id,
const char* name) {
ASSERT_NE(NULL, address);
ExternalReferenceEntry entry;
entry.address = address;
entry.code = EncodeExternal(type, id);
entry.name = name;
ASSERT_NE(0, entry.code);
refs_.Add(entry);
if (id > max_id_[type]) max_id_[type] = id;
}
void ExternalReferenceTable::PopulateTable(Isolate* isolate) {
for (int type_code = 0; type_code < kTypeCodeCount; type_code++) {
max_id_[type_code] = 0;
}
// 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;
};
static const RefTableEntry ref_table[] = {
// Builtins
#define DEF_ENTRY_C(name, ignored) \
{ C_BUILTIN, \
Builtins::c_##name, \
"Builtins::" #name },
BUILTIN_LIST_C(DEF_ENTRY_C)
#undef DEF_ENTRY_C
#define DEF_ENTRY_C(name, ignored) \
{ BUILTIN, \
Builtins::k##name, \
"Builtins::" #name },
#define DEF_ENTRY_A(name, kind, state, extra) DEF_ENTRY_C(name, ignored)
BUILTIN_LIST_C(DEF_ENTRY_C)
BUILTIN_LIST_A(DEF_ENTRY_A)
BUILTIN_LIST_DEBUG_A(DEF_ENTRY_A)
#undef DEF_ENTRY_C
#undef DEF_ENTRY_A
// Runtime functions
#define RUNTIME_ENTRY(name, nargs, ressize) \
{ RUNTIME_FUNCTION, \
Runtime::k##name, \
"Runtime::" #name },
RUNTIME_FUNCTION_LIST(RUNTIME_ENTRY)
#undef RUNTIME_ENTRY
// IC utilities
#define IC_ENTRY(name) \
{ IC_UTILITY, \
IC::k##name, \
"IC::" #name },
IC_UTIL_LIST(IC_ENTRY)
#undef IC_ENTRY
}; // 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,
isolate);
}
#ifdef ENABLE_DEBUGGER_SUPPORT
// Debug addresses
Add(Debug_Address(Debug::k_after_break_target_address).address(isolate),
DEBUG_ADDRESS,
Debug::k_after_break_target_address << kDebugIdShift,
"Debug::after_break_target_address()");
Add(Debug_Address(Debug::k_debug_break_slot_address).address(isolate),
DEBUG_ADDRESS,
Debug::k_debug_break_slot_address << kDebugIdShift,
"Debug::debug_break_slot_address()");
Add(Debug_Address(Debug::k_debug_break_return_address).address(isolate),
DEBUG_ADDRESS,
Debug::k_debug_break_return_address << kDebugIdShift,
"Debug::debug_break_return_address()");
Add(Debug_Address(Debug::k_restarter_frame_function_pointer).address(isolate),
DEBUG_ADDRESS,
Debug::k_restarter_frame_function_pointer << kDebugIdShift,
"Debug::restarter_frame_function_pointer_address()");
#endif
// Stat counters
struct StatsRefTableEntry {
StatsCounter* (Counters::*counter)();
uint16_t id;
const char* name;
};
const StatsRefTableEntry stats_ref_table[] = {
#define COUNTER_ENTRY(name, caption) \
{ &Counters::name, \
Counters::k_##name, \
"Counters::" #name },
STATS_COUNTER_LIST_1(COUNTER_ENTRY)
STATS_COUNTER_LIST_2(COUNTER_ENTRY)
#undef COUNTER_ENTRY
}; // end of stats_ref_table[].
Counters* counters = isolate->counters();
for (size_t i = 0; i < ARRAY_SIZE(stats_ref_table); ++i) {
Add(reinterpret_cast<Address>(GetInternalPointer(
(counters->*(stats_ref_table[i].counter))())),
STATS_COUNTER,
stats_ref_table[i].id,
stats_ref_table[i].name);
}
// Top addresses
const char* AddressNames[] = {
#define BUILD_NAME_LITERAL(CamelName, hacker_name) \
"Isolate::" #hacker_name "_address",
FOR_EACH_ISOLATE_ADDRESS_NAME(BUILD_NAME_LITERAL)
NULL
#undef C
};
for (uint16_t i = 0; i < Isolate::kIsolateAddressCount; ++i) {
Add(isolate->get_address_from_id((Isolate::AddressId)i),
TOP_ADDRESS, i, AddressNames[i]);
}
// 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
StubCache* stub_cache = isolate->stub_cache();
// Stub cache tables
Add(stub_cache->key_reference(StubCache::kPrimary).address(),
STUB_CACHE_TABLE,
1,
"StubCache::primary_->key");
Add(stub_cache->value_reference(StubCache::kPrimary).address(),
STUB_CACHE_TABLE,
2,
"StubCache::primary_->value");
Add(stub_cache->key_reference(StubCache::kSecondary).address(),
STUB_CACHE_TABLE,
3,
"StubCache::secondary_->key");
Add(stub_cache->value_reference(StubCache::kSecondary).address(),
STUB_CACHE_TABLE,
4,
"StubCache::secondary_->value");
// Runtime entries
Add(ExternalReference::perform_gc_function(isolate).address(),
RUNTIME_ENTRY,
1,
"Runtime::PerformGC");
Add(ExternalReference::fill_heap_number_with_random_function(
isolate).address(),
RUNTIME_ENTRY,
2,
"V8::FillHeapNumberWithRandom");
Add(ExternalReference::random_uint32_function(isolate).address(),
RUNTIME_ENTRY,
3,
"V8::Random");
Add(ExternalReference::delete_handle_scope_extensions(isolate).address(),
RUNTIME_ENTRY,
4,
"HandleScope::DeleteExtensions");
Add(ExternalReference::
incremental_marking_record_write_function(isolate).address(),
RUNTIME_ENTRY,
5,
"IncrementalMarking::RecordWrite");
Add(ExternalReference::store_buffer_overflow_function(isolate).address(),
RUNTIME_ENTRY,
6,
"StoreBuffer::StoreBufferOverflow");
Add(ExternalReference::
incremental_evacuation_record_write_function(isolate).address(),
RUNTIME_ENTRY,
7,
"IncrementalMarking::RecordWrite");
// Miscellaneous
Add(ExternalReference::roots_array_start(isolate).address(),
UNCLASSIFIED,
3,
"Heap::roots_array_start()");
Add(ExternalReference::address_of_stack_limit(isolate).address(),
UNCLASSIFIED,
4,
"StackGuard::address_of_jslimit()");
Add(ExternalReference::address_of_real_stack_limit(isolate).address(),
UNCLASSIFIED,
5,
"StackGuard::address_of_real_jslimit()");
#ifndef V8_INTERPRETED_REGEXP
Add(ExternalReference::address_of_regexp_stack_limit(isolate).address(),
UNCLASSIFIED,
6,
"RegExpStack::limit_address()");
Add(ExternalReference::address_of_regexp_stack_memory_address(
isolate).address(),
UNCLASSIFIED,
7,
"RegExpStack::memory_address()");
Add(ExternalReference::address_of_regexp_stack_memory_size(isolate).address(),
UNCLASSIFIED,
8,
"RegExpStack::memory_size()");
Add(ExternalReference::address_of_static_offsets_vector(isolate).address(),
UNCLASSIFIED,
9,
"OffsetsVector::static_offsets_vector");
#endif // V8_INTERPRETED_REGEXP
Add(ExternalReference::new_space_start(isolate).address(),
UNCLASSIFIED,
10,
"Heap::NewSpaceStart()");
Add(ExternalReference::new_space_mask(isolate).address(),
UNCLASSIFIED,
11,
"Heap::NewSpaceMask()");
Add(ExternalReference::heap_always_allocate_scope_depth(isolate).address(),
UNCLASSIFIED,
12,
"Heap::always_allocate_scope_depth()");
Add(ExternalReference::new_space_allocation_limit_address(isolate).address(),
UNCLASSIFIED,
14,
"Heap::NewSpaceAllocationLimitAddress()");
Add(ExternalReference::new_space_allocation_top_address(isolate).address(),
UNCLASSIFIED,
15,
"Heap::NewSpaceAllocationTopAddress()");
#ifdef ENABLE_DEBUGGER_SUPPORT
Add(ExternalReference::debug_break(isolate).address(),
UNCLASSIFIED,
16,
"Debug::Break()");
Add(ExternalReference::debug_step_in_fp_address(isolate).address(),
UNCLASSIFIED,
17,
"Debug::step_in_fp_addr()");
#endif
Add(ExternalReference::double_fp_operation(Token::ADD, isolate).address(),
UNCLASSIFIED,
18,
"add_two_doubles");
Add(ExternalReference::double_fp_operation(Token::SUB, isolate).address(),
UNCLASSIFIED,
19,
"sub_two_doubles");
Add(ExternalReference::double_fp_operation(Token::MUL, isolate).address(),
UNCLASSIFIED,
20,
"mul_two_doubles");
Add(ExternalReference::double_fp_operation(Token::DIV, isolate).address(),
UNCLASSIFIED,
21,
"div_two_doubles");
Add(ExternalReference::double_fp_operation(Token::MOD, isolate).address(),
UNCLASSIFIED,
22,
"mod_two_doubles");
Add(ExternalReference::compare_doubles(isolate).address(),
UNCLASSIFIED,
23,
"compare_doubles");
#ifndef V8_INTERPRETED_REGEXP
Add(ExternalReference::re_case_insensitive_compare_uc16(isolate).address(),
UNCLASSIFIED,
24,
"NativeRegExpMacroAssembler::CaseInsensitiveCompareUC16()");
Add(ExternalReference::re_check_stack_guard_state(isolate).address(),
UNCLASSIFIED,
25,
"RegExpMacroAssembler*::CheckStackGuardState()");
Add(ExternalReference::re_grow_stack(isolate).address(),
UNCLASSIFIED,
26,
"NativeRegExpMacroAssembler::GrowStack()");
Add(ExternalReference::re_word_character_map().address(),
UNCLASSIFIED,
27,
"NativeRegExpMacroAssembler::word_character_map");
#endif // V8_INTERPRETED_REGEXP
// Keyed lookup cache.
Add(ExternalReference::keyed_lookup_cache_keys(isolate).address(),
UNCLASSIFIED,
28,
"KeyedLookupCache::keys()");
Add(ExternalReference::keyed_lookup_cache_field_offsets(isolate).address(),
UNCLASSIFIED,
29,
"KeyedLookupCache::field_offsets()");
Add(ExternalReference::transcendental_cache_array_address(isolate).address(),
UNCLASSIFIED,
30,
"TranscendentalCache::caches()");
Add(ExternalReference::handle_scope_next_address().address(),
UNCLASSIFIED,
31,
"HandleScope::next");
Add(ExternalReference::handle_scope_limit_address().address(),
UNCLASSIFIED,
32,
"HandleScope::limit");
Add(ExternalReference::handle_scope_level_address().address(),
UNCLASSIFIED,
33,
"HandleScope::level");
Add(ExternalReference::new_deoptimizer_function(isolate).address(),
UNCLASSIFIED,
34,
"Deoptimizer::New()");
Add(ExternalReference::compute_output_frames_function(isolate).address(),
UNCLASSIFIED,
35,
"Deoptimizer::ComputeOutputFrames()");
Add(ExternalReference::address_of_min_int().address(),
UNCLASSIFIED,
36,
"LDoubleConstant::min_int");
Add(ExternalReference::address_of_one_half().address(),
UNCLASSIFIED,
37,
"LDoubleConstant::one_half");
Add(ExternalReference::isolate_address().address(),
UNCLASSIFIED,
38,
"isolate");
Add(ExternalReference::address_of_minus_zero().address(),
UNCLASSIFIED,
39,
"LDoubleConstant::minus_zero");
Add(ExternalReference::address_of_negative_infinity().address(),
UNCLASSIFIED,
40,
"LDoubleConstant::negative_infinity");
Add(ExternalReference::power_double_double_function(isolate).address(),
UNCLASSIFIED,
41,
"power_double_double_function");
Add(ExternalReference::power_double_int_function(isolate).address(),
UNCLASSIFIED,
42,
"power_double_int_function");
Add(ExternalReference::store_buffer_top(isolate).address(),
UNCLASSIFIED,
43,
"store_buffer_top");
Add(ExternalReference::address_of_canonical_non_hole_nan().address(),
UNCLASSIFIED,
44,
"canonical_nan");
Add(ExternalReference::address_of_the_hole_nan().address(),
UNCLASSIFIED,
45,
"the_hole_nan");
}
ExternalReferenceEncoder::ExternalReferenceEncoder()
: encodings_(Match),
isolate_(Isolate::Current()) {
ExternalReferenceTable* external_references =
ExternalReferenceTable::instance(isolate_);
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);
ASSERT(key == NULL || index >= 0);
return index >=0 ?
ExternalReferenceTable::instance(isolate_)->code(index) : 0;
}
const char* ExternalReferenceEncoder::NameOfAddress(Address key) const {
int index = IndexOf(key);
return index >= 0 ?
ExternalReferenceTable::instance(isolate_)->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
: static_cast<int>(reinterpret_cast<intptr_t>(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)),
isolate_(Isolate::Current()) {
ExternalReferenceTable* external_references =
ExternalReferenceTable::instance(isolate_);
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_);
}
bool Serializer::serialization_enabled_ = false;
bool Serializer::too_late_to_enable_now_ = false;
Deserializer::Deserializer(SnapshotByteSource* source)
: isolate_(NULL),
source_(source),
external_reference_decoder_(NULL) {
}
// 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.
Address Deserializer::Allocate(int space_index, Space* space, int size) {
Address address;
if (!SpaceIsLarge(space_index)) {
ASSERT(!SpaceIsPaged(space_index) ||
size <= Page::kPageSize - Page::kObjectStartOffset);
MaybeObject* maybe_new_allocation;
if (space_index == NEW_SPACE) {
maybe_new_allocation =
reinterpret_cast<NewSpace*>(space)->AllocateRaw(size);
} else {
maybe_new_allocation =
reinterpret_cast<PagedSpace*>(space)->AllocateRaw(size);
}
ASSERT(!maybe_new_allocation->IsFailure());
Object* new_allocation = maybe_new_allocation->ToObjectUnchecked();
HeapObject* new_object = HeapObject::cast(new_allocation);
address = new_object->address();
high_water_[space_index] = address + size;
} else {
ASSERT(SpaceIsLarge(space_index));
LargeObjectSpace* lo_space = reinterpret_cast<LargeObjectSpace*>(space);
Object* new_allocation;
if (space_index == kLargeData || space_index == kLargeFixedArray) {
new_allocation =
lo_space->AllocateRaw(size, NOT_EXECUTABLE)->ToObjectUnchecked();
} else {
ASSERT_EQ(kLargeCode, space_index);
new_allocation =
lo_space->AllocateRaw(size, EXECUTABLE)->ToObjectUnchecked();
}
HeapObject* new_object = HeapObject::cast(new_allocation);
// Record all large objects in the same space.
address = new_object->address();
pages_[LO_SPACE].Add(address);
}
last_object_address_ = address;
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.
HeapObject* Deserializer::GetAddressFromEnd(int space) {
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.
HeapObject* Deserializer::GetAddressFromStart(int space) {
int offset = source_->GetInt();
if (SpaceIsLarge(space)) {
// Large spaces have one object per 'page'.
return HeapObject::FromAddress(pages_[LO_SPACE][offset]);
}
offset <<= kObjectAlignmentBits;
if (space == NEW_SPACE) {
// New space has only one space - numbered 0.
return HeapObject::FromAddress(pages_[space][0] + offset);
}
ASSERT(SpaceIsPaged(space));
int page_of_pointee = offset >> kPageSizeBits;
Address object_address = pages_[space][page_of_pointee] +
(offset & Page::kPageAlignmentMask);
return HeapObject::FromAddress(object_address);
}
void Deserializer::Deserialize() {
isolate_ = Isolate::Current();
ASSERT(isolate_ != NULL);
// 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, isolate_->thread_manager()->FirstThreadStateInUse());
// No active handles.
ASSERT(isolate_->handle_scope_implementer()->blocks()->is_empty());
// Make sure the entire partial snapshot cache is traversed, filling it with
// valid object pointers.
isolate_->set_serialize_partial_snapshot_cache_length(
Isolate::kPartialSnapshotCacheCapacity);
ASSERT_EQ(NULL, external_reference_decoder_);
external_reference_decoder_ = new ExternalReferenceDecoder();
isolate_->heap()->IterateStrongRoots(this, VISIT_ONLY_STRONG);
isolate_->heap()->IterateWeakRoots(this, VISIT_ALL);
isolate_->heap()->set_global_contexts_list(
isolate_->heap()->undefined_value());
// Update data pointers to the external strings containing natives sources.
for (int i = 0; i < Natives::GetBuiltinsCount(); i++) {
Object* source = isolate_->heap()->natives_source_cache()->get(i);
if (!source->IsUndefined()) {
ExternalAsciiString::cast(source)->update_data_cache();
}
}
}
void Deserializer::DeserializePartial(Object** root) {
isolate_ = Isolate::Current();
// 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);
}
Deserializer::~Deserializer() {
ASSERT(source_->AtEOF());
if (external_reference_decoder_) {
delete external_reference_decoder_;
external_reference_decoder_ = NULL;
}
}
// This is called on the roots. It is the driver of the deserialization
// process. It is also called on the body of each function.
void Deserializer::VisitPointers(Object** start, Object** end) {
// 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);
}
// 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 FreeSpace map is not set up by the
// time we need to use it to mark the space at the end of a page free.
void Deserializer::ReadObject(int space_number,
Space* space,
Object** write_back) {
int size = source_->GetInt() << kObjectAlignmentBits;
Address address = Allocate(space_number, space, size);
*write_back = HeapObject::FromAddress(address);
Object** current = reinterpret_cast<Object**>(address);
Object** limit = current + (size >> kPointerSizeLog2);
if (FLAG_log_snapshot_positions) {
LOG(isolate_, SnapshotPositionEvent(address, source_->position()));
}
ReadChunk(current, limit, space_number, address);
#ifdef DEBUG
bool is_codespace = (space == HEAP->code_space()) ||
((space == HEAP->lo_space()) && (space_number == kLargeCode));
ASSERT(HeapObject::FromAddress(address)->IsCode() == is_codespace);
#endif
}
// 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 = isolate->heap()->new_space(); \
} else if (space_number == OLD_POINTER_SPACE) { \
dest_space = isolate->heap()->old_pointer_space(); \
} else if (space_number == OLD_DATA_SPACE) { \
dest_space = isolate->heap()->old_data_space(); \
} else if (space_number == CODE_SPACE) { \
dest_space = isolate->heap()->code_space(); \
} else if (space_number == MAP_SPACE) { \
dest_space = isolate->heap()->map_space(); \
} else if (space_number == CELL_SPACE) { \
dest_space = isolate->heap()->cell_space(); \
} else { \
ASSERT(space_number >= LO_SPACE); \
dest_space = isolate->heap()->lo_space(); \
}
static const int kUnknownOffsetFromStart = -1;
void Deserializer::ReadChunk(Object** current,
Object** limit,
int source_space,
Address current_object_address) {
Isolate* const isolate = isolate_;
bool write_barrier_needed = (current_object_address != NULL &&
source_space != NEW_SPACE &&
source_space != CELL_SPACE &&
source_space != CODE_SPACE &&
source_space != OLD_DATA_SPACE);
while (current < limit) {
int data = source_->Get();
switch (data) {
#define CASE_STATEMENT(where, how, within, space_number) \
case where + how + within + space_number: \
ASSERT((where & ~kPointedToMask) == 0); \
ASSERT((how & ~kHowToCodeMask) == 0); \
ASSERT((within & ~kWhereToPointMask) == 0); \
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); \
} 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 = isolate->heap()->roots_array_start()[root_id]; \
emit_write_barrier = isolate->heap()->InNewSpace(new_object); \
} else if (where == kPartialSnapshotCache) { \
int cache_index = source_->GetInt(); \
new_object = isolate->serialize_partial_snapshot_cache() \
[cache_index]; \
emit_write_barrier = isolate->heap()->InNewSpace(new_object); \
} 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); \
new_object = GetAddressFromEnd(data & kSpaceMask); \
} else { \
ASSERT(where == kFromStart); \
if (offset_from_start == kUnknownOffsetFromStart) { \
emit_write_barrier = (space_number == 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 && write_barrier_needed) { \
Address current_address = reinterpret_cast<Address>(current); \
isolate->heap()->RecordWrite( \
current_object_address, \
static_cast<int>(current_address - current_object_address)); \
} \
if (!current_was_incremented) { \
current++; \
} \
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 ONE_PER_CODE_SPACE(where, how, within) \
CASE_STATEMENT(where, how, within, CODE_SPACE) \
CASE_BODY(where, how, within, CODE_SPACE, kUnknownOffsetFromStart) \
CASE_STATEMENT(where, how, within, kLargeCode) \
CASE_BODY(where, how, within, kLargeCode, kUnknownOffsetFromStart)
#define FOUR_CASES(byte_code) \
case byte_code: \
case byte_code + 1: \
case byte_code + 2: \
case byte_code + 3:
#define SIXTEEN_CASES(byte_code) \
FOUR_CASES(byte_code) \
FOUR_CASES(byte_code + 4) \
FOUR_CASES(byte_code + 8) \
FOUR_CASES(byte_code + 12)
// We generate 15 cases and bodies that process special tags that combine
// the raw data tag and the length into one byte.
#define RAW_CASE(index, size) \
case kRawData + index: { \
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
// Deserialize a chunk of raw data that doesn't have one of the popular
// lengths.
case kRawData: {
int size = source_->GetInt();
byte* raw_data_out = reinterpret_cast<byte*>(current);
source_->CopyRaw(raw_data_out, size);
current = reinterpret_cast<Object**>(raw_data_out + size);
break;
}
SIXTEEN_CASES(kRootArrayLowConstants)
SIXTEEN_CASES(kRootArrayHighConstants) {
int root_id = RootArrayConstantFromByteCode(data);
Object* object = isolate->heap()->roots_array_start()[root_id];
ASSERT(!isolate->heap()->InNewSpace(object));
*current++ = object;
break;
}
case kRepeat: {
int repeats = source_->GetInt();
Object* object = current[-1];
ASSERT(!isolate->heap()->InNewSpace(object));
for (int i = 0; i < repeats; i++) current[i] = object;
current += repeats;
break;
}
STATIC_ASSERT(kRootArrayNumberOfConstantEncodings ==
Heap::kOldSpaceRoots);
STATIC_ASSERT(kMaxRepeats == 12);
FOUR_CASES(kConstantRepeat)
FOUR_CASES(kConstantRepeat + 4)
FOUR_CASES(kConstantRepeat + 8) {
int repeats = RepeatsForCode(data);
Object* object = current[-1];
ASSERT(!isolate->heap()->InNewSpace(object));
for (int i = 0; i < repeats; i++) current[i] = object;
current += repeats;
break;
}
// Deserialize a new object and write a pointer to it to the current
// object.
ONE_PER_SPACE(kNewObject, kPlain, kStartOfObject)
// Support for direct instruction pointers in functions
ONE_PER_CODE_SPACE(kNewObject, kPlain, kFirstInstruction)
// 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 or the instruction pointer in a function
// object.
ALL_SPACES(kBackref, kFromCode, kFirstInstruction)
ALL_SPACES(kBackref, kPlain, 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)
ALL_SPACES(kFromStart, kPlain, kFirstInstruction)
// 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 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 code entry in the partial snapshots cache and
// write a pointer to it to the current object.
CASE_STATEMENT(kPartialSnapshotCache, kPlain, kFirstInstruction, 0)
CASE_BODY(kPartialSnapshotCache,
kPlain,
kFirstInstruction,
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 ASSIGN_DEST_SPACE
case kNewPage: {
int space = source_->Get();
pages_[space].Add(last_object_address_);
if (space == CODE_SPACE) {
CPU::FlushICache(last_object_address_, Page::kPageSize);
}
break;
}
case kSkip: {
current++;
break;
}
case kNativesStringResource: {
int index = source_->Get();
Vector<const char> source_vector = Natives::GetRawScriptSource(index);
NativesExternalStringResource* resource =
new NativesExternalStringResource(isolate->bootstrapper(),
source_vector.start(),
source_vector.length());
*current++ = reinterpret_cast<Object*>(resource);
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.
UNREACHABLE();
}
default:
UNREACHABLE();
}
}
ASSERT_EQ(current, limit);
}
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) {
if (integer >= static_cast<uintptr_t>(1u) << shift) {
Put((static_cast<int>((integer >> shift)) & 0x7f) | 0x80, "IntPart");
}
}
PutSection(static_cast<int>(integer & 0x7f), "IntLastPart");
}
#ifdef DEBUG
void Deserializer::Synchronize(const char* tag) {
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.
ASSERT_EQ(kSynchronize, data);
do {
int character = source_->Get();
if (character == 0) break;
if (FLAG_debug_serialization) {
PrintF("%c", character);
}
} while (true);
if (FLAG_debug_serialization) {
PrintF("\n");
}
}
void Serializer::Synchronize(const char* tag) {
sink_->Put(kSynchronize, tag);
int character;
do {
character = *tag++;
sink_->PutSection(character, "TagCharacter");
} while (character != 0);
}
#endif
Serializer::Serializer(SnapshotByteSink* sink)
: sink_(sink),
current_root_index_(0),
external_reference_encoder_(new ExternalReferenceEncoder),
large_object_total_(0),
root_index_wave_front_(0) {
// The serializer is meant to be used only to generate initial heap images
// from a context in which there is only one isolate.
ASSERT(Isolate::Current()->IsDefaultIsolate());
for (int i = 0; i <= LAST_SPACE; i++) {
fullness_[i] = 0;
}
}
Serializer::~Serializer() {
delete external_reference_encoder_;
}
void StartupSerializer::SerializeStrongReferences() {
Isolate* isolate = Isolate::Current();
// No active threads.
CHECK_EQ(NULL, Isolate::Current()->thread_manager()->FirstThreadStateInUse());
// No active or weak handles.
CHECK(isolate->handle_scope_implementer()->blocks()->is_empty());
CHECK_EQ(0, isolate->global_handles()->NumberOfWeakHandles());
// We don't support serializing installed extensions.
CHECK(!isolate->has_installed_extensions());
HEAP->IterateStrongRoots(this, VISIT_ONLY_STRONG);
}
void PartialSerializer::Serialize(Object** object) {
this->VisitPointer(object);
Isolate* isolate = Isolate::Current();
// 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 = isolate->serialize_partial_snapshot_cache_length();
index < Isolate::kPartialSnapshotCacheCapacity;
index++) {
isolate->serialize_partial_snapshot_cache()[index] =
isolate->heap()->undefined_value();
startup_serializer_->VisitPointer(
&isolate->serialize_partial_snapshot_cache()[index]);
}
isolate->set_serialize_partial_snapshot_cache_length(
Isolate::kPartialSnapshotCacheCapacity);
}
void Serializer::VisitPointers(Object** start, Object** end) {
Isolate* isolate = Isolate::Current();
for (Object** current = start; current < end; current++) {
if (start == isolate->heap()->roots_array_start()) {
root_index_wave_front_ =
Max(root_index_wave_front_, static_cast<intptr_t>(current - start));
}
if (reinterpret_cast<Address>(current) ==
isolate->heap()->store_buffer()->TopAddress()) {
sink_->Put(kSkip, "Skip");
} else if ((*current)->IsSmi()) {
sink_->Put(kRawData, "RawData");
sink_->PutInt(kPointerSize, "length");
for (int i = 0; i < kPointerSize; i++) {
sink_->Put(reinterpret_cast<byte*>(current)[i], "Byte");
}
} else {
SerializeObject(*current, kPlain, kStartOfObject);
}
}
}
// 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.
void SerializerDeserializer::Iterate(ObjectVisitor* visitor) {
Isolate* isolate = Isolate::Current();
visitor->VisitPointers(
isolate->serialize_partial_snapshot_cache(),
&isolate->serialize_partial_snapshot_cache()[
isolate->serialize_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) {
Isolate::Current()->set_serialize_partial_snapshot_cache_length(size);
}
int PartialSerializer::PartialSnapshotCacheIndex(HeapObject* heap_object) {
Isolate* isolate = Isolate::Current();
for (int i = 0;
i < isolate->serialize_partial_snapshot_cache_length();
i++) {
Object* entry = isolate->serialize_partial_snapshot_cache()[i];
if (entry == heap_object) return i;
}
// 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 = isolate->serialize_partial_snapshot_cache_length();
CHECK(length < Isolate::kPartialSnapshotCacheCapacity);
isolate->serialize_partial_snapshot_cache()[length] = heap_object;
startup_serializer_->VisitPointer(
&isolate->serialize_partial_snapshot_cache()[length]);
// We don't recurse from the startup snapshot generator into the partial
// snapshot generator.
ASSERT(length == isolate->serialize_partial_snapshot_cache_length());
isolate->set_serialize_partial_snapshot_cache_length(length + 1);
return length;
}
int Serializer::RootIndex(HeapObject* heap_object) {
Heap* heap = HEAP;
if (heap->InNewSpace(heap_object)) return kInvalidRootIndex;
for (int i = 0; i < root_index_wave_front_; i++) {
Object* root = heap->roots_array_start()[i];
if (!root->IsSmi() && root == heap_object) return i;
}
return kInvalidRootIndex;
}
// 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,
HowToCode how_to_code,
WhereToPoint where_to_point) {
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;
}
} 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;
}
}
// 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;
if (from_start) {
sink_->Put(kFromStart + how_to_code + where_to_point + space, "RefSer");
sink_->PutInt(address, "address");
} else {
sink_->Put(kBackref + how_to_code + where_to_point + space, "BackRefSer");
sink_->PutInt(address, "address");
}
}
void StartupSerializer::SerializeObject(
Object* o,
HowToCode how_to_code,
WhereToPoint where_to_point) {
CHECK(o->IsHeapObject());
HeapObject* heap_object = HeapObject::cast(o);
int root_index;
if ((root_index = RootIndex(heap_object)) != kInvalidRootIndex) {
PutRoot(root_index, heap_object, how_to_code, where_to_point);
return;
}
if (address_mapper_.IsMapped(heap_object)) {
int space = SpaceOfAlreadySerializedObject(heap_object);
int address = address_mapper_.MappedTo(heap_object);
SerializeReferenceToPreviousObject(space,
address,
how_to_code,
where_to_point);
} else {
// Object has not yet been serialized. Serialize it here.
ObjectSerializer object_serializer(this,
heap_object,
sink_,
how_to_code,
where_to_point);
object_serializer.Serialize();
}
}
void StartupSerializer::SerializeWeakReferences() {
for (int i = Isolate::Current()->serialize_partial_snapshot_cache_length();
i < Isolate::kPartialSnapshotCacheCapacity;
i++) {
sink_->Put(kRootArray + kPlain + kStartOfObject, "RootSerialization");
sink_->PutInt(Heap::kUndefinedValueRootIndex, "root_index");
}
HEAP->IterateWeakRoots(this, VISIT_ALL);
}
void Serializer::PutRoot(int root_index,
HeapObject* object,
SerializerDeserializer::HowToCode how_to_code,
SerializerDeserializer::WhereToPoint where_to_point) {
if (how_to_code == kPlain &&
where_to_point == kStartOfObject &&
root_index < kRootArrayNumberOfConstantEncodings &&
!HEAP->InNewSpace(object)) {
if (root_index < kRootArrayNumberOfLowConstantEncodings) {
sink_->Put(kRootArrayLowConstants + root_index, "RootLoConstant");
} else {
sink_->Put(kRootArrayHighConstants + root_index -
kRootArrayNumberOfLowConstantEncodings,
"RootHiConstant");
}
} else {
sink_->Put(kRootArray + how_to_code + where_to_point, "RootSerialization");
sink_->PutInt(root_index, "root_index");
}
}
void PartialSerializer::SerializeObject(
Object* o,
HowToCode how_to_code,
WhereToPoint where_to_point) {
CHECK(o->IsHeapObject());
HeapObject* heap_object = HeapObject::cast(o);
int root_index;
if ((root_index = RootIndex(heap_object)) != kInvalidRootIndex) {
PutRoot(root_index, heap_object, how_to_code, where_to_point);
return;
}
if (ShouldBeInThePartialSnapshotCache(heap_object)) {
int cache_index = PartialSnapshotCacheIndex(heap_object);
sink_->Put(kPartialSnapshotCache + how_to_code + where_to_point,
"PartialSnapshotCache");
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,
how_to_code,
where_to_point);
} else {
// Object has not yet been serialized. Serialize it here.
ObjectSerializer serializer(this,
heap_object,
sink_,
how_to_code,
where_to_point);
serializer.Serialize();
}
}
void Serializer::ObjectSerializer::Serialize() {
int space = Serializer::SpaceOfObject(object_);
int size = object_->Size();
sink_->Put(kNewObject + reference_representation_ + space,
"ObjectSerialization");
sink_->PutInt(size >> kObjectAlignmentBits, "Size in words");
LOG(i::Isolate::Current(),
SnapshotPositionEvent(object_->address(), sink_->Position()));
// Mark this object as already serialized.
bool start_new_page;
int offset = serializer_->Allocate(space, size, &start_new_page);
serializer_->address_mapper()->AddMapping(object_, offset);
if (start_new_page) {
sink_->Put(kNewPage, "NewPage");
sink_->PutSection(space, "NewPageSpace");
}
// Serialize the map (first word of the object).
serializer_->SerializeObject(object_->map(), kPlain, kStartOfObject);
// Serialize the rest of the object.
CHECK_EQ(0, bytes_processed_so_far_);
bytes_processed_so_far_ = kPointerSize;
object_->IterateBody(object_->map()->instance_type(), size, this);
OutputRawData(object_->address() + size);
}
void Serializer::ObjectSerializer::VisitPointers(Object** start,
Object** end) {
Object** current = start;
while (current < end) {
while (current < end && (*current)->IsSmi()) current++;
if (current < end) OutputRawData(reinterpret_cast<Address>(current));
while (current < end && !(*current)->IsSmi()) {
HeapObject* current_contents = HeapObject::cast(*current);
int root_index = serializer_->RootIndex(current_contents);
// Repeats are not subject to the write barrier so there are only some
// objects that can be used in a repeat encoding. These are the early
// ones in the root array that are never in new space.
if (current != start &&
root_index != kInvalidRootIndex &&
root_index < kRootArrayNumberOfConstantEncodings &&
current_contents == current[-1]) {
ASSERT(!HEAP->InNewSpace(current_contents));
int repeat_count = 1;
while (current < end - 1 && current[repeat_count] == current_contents) {
repeat_count++;
}
current += repeat_count;
bytes_processed_so_far_ += repeat_count * kPointerSize;
if (repeat_count > kMaxRepeats) {
sink_->Put(kRepeat, "SerializeRepeats");
sink_->PutInt(repeat_count, "SerializeRepeats");
} else {
sink_->Put(CodeForRepeats(repeat_count), "SerializeRepeats");
}
} else {
serializer_->SerializeObject(current_contents, kPlain, kStartOfObject);
bytes_processed_so_far_ += kPointerSize;
current++;
}
}
}
}
void Serializer::ObjectSerializer::VisitEmbeddedPointer(RelocInfo* rinfo) {
Object** current = rinfo->target_object_address();
OutputRawData(rinfo->target_address_address());
HowToCode representation = rinfo->IsCodedSpecially() ? kFromCode : kPlain;
serializer_->SerializeObject(*current, representation, kStartOfObject);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitExternalReferences(Address* start,
Address* end) {
Address references_start = reinterpret_cast<Address>(start);
OutputRawData(references_start);
for (Address* current = start; current < end; current++) {
sink_->Put(kExternalReference + kPlain + kStartOfObject, "ExternalRef");
int reference_id = serializer_->EncodeExternalReference(*current);
sink_->PutInt(reference_id, "reference id");
}
bytes_processed_so_far_ += static_cast<int>((end - start) * kPointerSize);
}
void Serializer::ObjectSerializer::VisitExternalReference(RelocInfo* rinfo) {
Address references_start = rinfo->target_address_address();
OutputRawData(references_start);
Address* current = rinfo->target_reference_address();
int representation = rinfo->IsCodedSpecially() ?
kFromCode + kStartOfObject : kPlain + kStartOfObject;
sink_->Put(kExternalReference + representation, "ExternalRef");
int reference_id = serializer_->EncodeExternalReference(*current);
sink_->PutInt(reference_id, "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitRuntimeEntry(RelocInfo* rinfo) {
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);
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");
sink_->PutInt(encoding, "reference id");
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeTarget(RelocInfo* rinfo) {
CHECK(RelocInfo::IsCodeTarget(rinfo->rmode()));
Address target_start = rinfo->target_address_address();
OutputRawData(target_start);
Code* target = Code::GetCodeFromTargetAddress(rinfo->target_address());
serializer_->SerializeObject(target, kFromCode, kFirstInstruction);
bytes_processed_so_far_ += rinfo->target_address_size();
}
void Serializer::ObjectSerializer::VisitCodeEntry(Address entry_address) {
Code* target = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
OutputRawData(entry_address);
serializer_->SerializeObject(target, kPlain, kFirstInstruction);
bytes_processed_so_far_ += kPointerSize;
}
void Serializer::ObjectSerializer::VisitGlobalPropertyCell(RelocInfo* rinfo) {
// We shouldn't have any global property cell references in code
// objects in the snapshot.
UNREACHABLE();
}
void Serializer::ObjectSerializer::VisitExternalAsciiString(
v8::String::ExternalAsciiStringResource** resource_pointer) {
Address references_start = reinterpret_cast<Address>(resource_pointer);
OutputRawData(references_start);
for (int i = 0; i < Natives::GetBuiltinsCount(); i++) {
Object* source = HEAP->natives_source_cache()->get(i);
if (!source->IsUndefined()) {
ExternalAsciiString* string = ExternalAsciiString::cast(source);
typedef v8::String::ExternalAsciiStringResource Resource;
const Resource* resource = string->resource();
if (resource == *resource_pointer) {
sink_->Put(kNativesStringResource, "NativesStringResource");
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();
}
void Serializer::ObjectSerializer::OutputRawData(Address up_to) {
Address object_start = object_->address();
int up_to_offset = static_cast<int>(up_to - object_start);
int skipped = up_to_offset - bytes_processed_so_far_;
// 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.
ASSERT(skipped >= 0);
if (skipped != 0) {
Address base = object_start + bytes_processed_so_far_;
#define RAW_CASE(index, length) \
if (skipped == length) { \
sink_->PutSection(kRawData + index, "RawDataFixed"); \
} else /* NOLINT */
COMMON_RAW_LENGTHS(RAW_CASE)
#undef RAW_CASE
{ /* NOLINT */
sink_->Put(kRawData, "RawData");
sink_->PutInt(skipped, "length");
}
for (int i = 0; i < skipped; i++) {
unsigned int data = base[i];
sink_->PutSection(data, "Byte");
}
bytes_processed_so_far_ += skipped;
}
}
int Serializer::SpaceOfObject(HeapObject* object) {
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;
}
int Serializer::SpaceOfAlreadySerializedObject(HeapObject* object) {
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;
}
int Serializer::Allocate(int space, int size, bool* new_page) {
CHECK(space >= 0 && space < kNumberOfSpaces);
if (SpaceIsLarge(space)) {
// In large object space we merely number the objects instead of trying to
// determine some sort of address.
*new_page = true;
large_object_total_ += size;
return fullness_[LO_SPACE]++;
}
*new_page = false;
if (fullness_[space] == 0) {
*new_page = true;
}
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.
CHECK(IsPowerOf2(Page::kPageSize));
int used_in_this_page = (fullness_[space] & (Page::kPageSize - 1));
CHECK(size <= Page::kObjectAreaSize);
if (used_in_this_page + size > Page::kObjectAreaSize) {
*new_page = true;
fullness_[space] = RoundUp(fullness_[space], Page::kPageSize);
}
}
int allocation_address = fullness_[space];
fullness_[space] = allocation_address + size;
return allocation_address;
}
} } // namespace v8::internal
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