v8/src/serialize.h
mstarzinger@chromium.org 5834284848 Refactor embedded pointer visitors for the serializer
This patch continues the refactoring that started in r9597 and
extends it with support for the serializer.
This is required for MIPS support in the serializer.

Review URL: http://codereview.chromium.org/8467010
Patch from Gergely Kis <gergely@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9971 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2011-11-11 12:28:42 +00:00

656 lines
21 KiB
C++

// Copyright 2006-2009 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.
#ifndef V8_SERIALIZE_H_
#define V8_SERIALIZE_H_
#include "hashmap.h"
namespace v8 {
namespace internal {
// A TypeCode is used to distinguish different kinds of external reference.
// It is a single bit to make testing for types easy.
enum TypeCode {
UNCLASSIFIED, // One-of-a-kind references.
BUILTIN,
RUNTIME_FUNCTION,
IC_UTILITY,
DEBUG_ADDRESS,
STATS_COUNTER,
TOP_ADDRESS,
C_BUILTIN,
EXTENSION,
ACCESSOR,
RUNTIME_ENTRY,
STUB_CACHE_TABLE
};
const int kTypeCodeCount = STUB_CACHE_TABLE + 1;
const int kFirstTypeCode = UNCLASSIFIED;
const int kReferenceIdBits = 16;
const int kReferenceIdMask = (1 << kReferenceIdBits) - 1;
const int kReferenceTypeShift = kReferenceIdBits;
const int kDebugRegisterBits = 4;
const int kDebugIdShift = kDebugRegisterBits;
// 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(Isolate* isolate);
~ExternalReferenceTable() { }
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:
explicit ExternalReferenceTable(Isolate* isolate) : refs_(64) {
PopulateTable(isolate);
}
struct ExternalReferenceEntry {
Address address;
uint32_t code;
const char* name;
};
void PopulateTable(Isolate* isolate);
// For a few types of references, we can get their address from their id.
void AddFromId(TypeCode type,
uint16_t id,
const char* name,
Isolate* isolate);
// For other types of references, the caller will figure out the address.
void Add(Address address, TypeCode type, uint16_t id, const char* name);
List<ExternalReferenceEntry> refs_;
int max_id_[kTypeCodeCount];
};
class ExternalReferenceEncoder {
public:
ExternalReferenceEncoder();
uint32_t Encode(Address key) const;
const char* NameOfAddress(Address key) const;
private:
HashMap encodings_;
static uint32_t Hash(Address key) {
return static_cast<uint32_t>(reinterpret_cast<uintptr_t>(key) >> 2);
}
int IndexOf(Address key) const;
static bool Match(void* key1, void* key2) { return key1 == key2; }
void Put(Address key, int index);
Isolate* isolate_;
};
class ExternalReferenceDecoder {
public:
ExternalReferenceDecoder();
~ExternalReferenceDecoder();
Address Decode(uint32_t key) const {
if (key == 0) return NULL;
return *Lookup(key);
}
private:
Address** encodings_;
Address* Lookup(uint32_t key) const {
int type = key >> kReferenceTypeShift;
ASSERT(kFirstTypeCode <= type && type < kTypeCodeCount);
int id = key & kReferenceIdMask;
return &encodings_[type][id];
}
void Put(uint32_t key, Address value) {
*Lookup(key) = value;
}
Isolate* isolate_;
};
class SnapshotByteSource {
public:
SnapshotByteSource(const byte* array, int length)
: data_(array), length_(length), position_(0) { }
bool HasMore() { return position_ < length_; }
int Get() {
ASSERT(position_ < length_);
return data_[position_++];
}
inline void CopyRaw(byte* to, int number_of_bytes);
inline int GetInt();
bool AtEOF() {
return position_ == length_;
}
int position() { return position_; }
private:
const byte* data_;
int length_;
int position_;
};
#define COMMON_RAW_LENGTHS(f) \
f(1, 1) \
f(2, 2) \
f(3, 3) \
f(4, 4) \
f(5, 5) \
f(6, 6) \
f(7, 7) \
f(8, 8) \
f(9, 12) \
f(10, 16) \
f(11, 20) \
f(12, 24) \
f(13, 28) \
f(14, 32) \
f(15, 36)
// The Serializer/Deserializer class is a common superclass for Serializer and
// Deserializer which is used to store common constants and methods used by
// both.
class SerializerDeserializer: public ObjectVisitor {
public:
static void Iterate(ObjectVisitor* visitor);
static void SetSnapshotCacheSize(int size);
protected:
// Where the pointed-to object can be found:
enum Where {
kNewObject = 0, // Object is next in snapshot.
// 1-8 One per space.
kRootArray = 0x9, // Object is found in root array.
kPartialSnapshotCache = 0xa, // Object is in the cache.
kExternalReference = 0xb, // Pointer to an external reference.
kSkip = 0xc, // Skip a pointer sized cell.
// 0xd-0xf Free.
kBackref = 0x10, // Object is described relative to end.
// 0x11-0x18 One per space.
// 0x19-0x1f Free.
kFromStart = 0x20, // Object is described relative to start.
// 0x21-0x28 One per space.
// 0x29-0x2f Free.
// 0x30-0x3f Used by misc tags below.
kPointedToMask = 0x3f
};
// How to code the pointer to the object.
enum HowToCode {
kPlain = 0, // Straight pointer.
// What this means depends on the architecture:
kFromCode = 0x40, // A pointer inlined in code.
kHowToCodeMask = 0x40
};
// Where to point within the object.
enum WhereToPoint {
kStartOfObject = 0,
kFirstInstruction = 0x80,
kWhereToPointMask = 0x80
};
// Misc.
// Raw data to be copied from the snapshot.
static const int kRawData = 0x30;
// Some common raw lengths: 0x31-0x3f
// A tag emitted at strategic points in the snapshot to delineate sections.
// If the deserializer does not find these at the expected moments then it
// is an indication that the snapshot and the VM do not fit together.
// Examine the build process for architecture, version or configuration
// mismatches.
static const int kSynchronize = 0x70;
// Used for the source code of the natives, which is in the executable, but
// is referred to from external strings in the snapshot.
static const int kNativesStringResource = 0x71;
static const int kNewPage = 0x72;
static const int kRepeat = 0x73;
static const int kConstantRepeat = 0x74;
// 0x74-0x7f Repeat last word (subtract 0x73 to get the count).
static const int kMaxRepeats = 0x7f - 0x73;
static int CodeForRepeats(int repeats) {
ASSERT(repeats >= 1 && repeats <= kMaxRepeats);
return 0x73 + repeats;
}
static int RepeatsForCode(int byte_code) {
ASSERT(byte_code >= kConstantRepeat && byte_code <= 0x7f);
return byte_code - 0x73;
}
static const int kRootArrayLowConstants = 0xb0;
// 0xb0-0xbf Things from the first 16 elements of the root array.
static const int kRootArrayHighConstants = 0xf0;
// 0xf0-0xff Things from the next 16 elements of the root array.
static const int kRootArrayNumberOfConstantEncodings = 0x20;
static const int kRootArrayNumberOfLowConstantEncodings = 0x10;
static int RootArrayConstantFromByteCode(int byte_code) {
int constant = (byte_code & 0xf) | ((byte_code & 0x40) >> 2);
ASSERT(constant >= 0 && constant < kRootArrayNumberOfConstantEncodings);
return constant;
}
static const int kLargeData = LAST_SPACE;
static const int kLargeCode = kLargeData + 1;
static const int kLargeFixedArray = kLargeCode + 1;
static const int kNumberOfSpaces = kLargeFixedArray + 1;
static const int kAnyOldSpace = -1;
// A bitmask for getting the space out of an instruction.
static const int kSpaceMask = 15;
static inline bool SpaceIsLarge(int space) { return space >= kLargeData; }
static inline bool SpaceIsPaged(int space) {
return space >= FIRST_PAGED_SPACE && space <= LAST_PAGED_SPACE;
}
};
int SnapshotByteSource::GetInt() {
// A little unwind to catch the really small ints.
int snapshot_byte = Get();
if ((snapshot_byte & 0x80) == 0) {
return snapshot_byte;
}
int accumulator = (snapshot_byte & 0x7f) << 7;
while (true) {
snapshot_byte = Get();
if ((snapshot_byte & 0x80) == 0) {
return accumulator | snapshot_byte;
}
accumulator = (accumulator | (snapshot_byte & 0x7f)) << 7;
}
UNREACHABLE();
return accumulator;
}
void SnapshotByteSource::CopyRaw(byte* to, int number_of_bytes) {
memcpy(to, data_ + position_, number_of_bytes);
position_ += number_of_bytes;
}
// A Deserializer reads a snapshot and reconstructs the Object graph it defines.
class Deserializer: public SerializerDeserializer {
public:
// Create a deserializer from a snapshot byte source.
explicit Deserializer(SnapshotByteSource* source);
virtual ~Deserializer();
// Deserialize the snapshot into an empty heap.
void Deserialize();
// Deserialize a single object and the objects reachable from it.
void DeserializePartial(Object** root);
#ifdef DEBUG
virtual void Synchronize(const char* tag);
#endif
private:
virtual void VisitPointers(Object** start, Object** end);
virtual void VisitExternalReferences(Address* start, Address* end) {
UNREACHABLE();
}
virtual void VisitRuntimeEntry(RelocInfo* rinfo) {
UNREACHABLE();
}
// Fills in some heap data in an area from start to end (non-inclusive). The
// space id is used for the write barrier. The object_address is the address
// of the object we are writing into, or NULL if we are not writing into an
// object, ie if we are writing a series of tagged values that are not on the
// heap.
void ReadChunk(
Object** start, Object** end, int space, Address object_address);
HeapObject* GetAddressFromStart(int space);
inline HeapObject* GetAddressFromEnd(int space);
Address Allocate(int space_number, Space* space, int size);
void ReadObject(int space_number, Space* space, Object** write_back);
// Cached current isolate.
Isolate* isolate_;
// Keep track of the pages in the paged spaces.
// (In large object space we are keeping track of individual objects
// rather than pages.) In new space we just need the address of the
// first object and the others will flow from that.
List<Address> pages_[SerializerDeserializer::kNumberOfSpaces];
SnapshotByteSource* source_;
// This is the address of the next object that will be allocated in each
// space. It is used to calculate the addresses of back-references.
Address high_water_[LAST_SPACE + 1];
// This is the address of the most recent object that was allocated. It
// is used to set the location of the new page when we encounter a
// START_NEW_PAGE_SERIALIZATION tag.
Address last_object_address_;
ExternalReferenceDecoder* external_reference_decoder_;
DISALLOW_COPY_AND_ASSIGN(Deserializer);
};
class SnapshotByteSink {
public:
virtual ~SnapshotByteSink() { }
virtual void Put(int byte, const char* description) = 0;
virtual void PutSection(int byte, const char* description) {
Put(byte, description);
}
void PutInt(uintptr_t integer, const char* description);
virtual int Position() = 0;
};
// Mapping objects to their location after deserialization.
// This is used during building, but not at runtime by V8.
class SerializationAddressMapper {
public:
SerializationAddressMapper()
: serialization_map_(new HashMap(&SerializationMatchFun)),
no_allocation_(new AssertNoAllocation()) { }
~SerializationAddressMapper() {
delete serialization_map_;
delete no_allocation_;
}
bool IsMapped(HeapObject* obj) {
return serialization_map_->Lookup(Key(obj), Hash(obj), false) != NULL;
}
int MappedTo(HeapObject* obj) {
ASSERT(IsMapped(obj));
return static_cast<int>(reinterpret_cast<intptr_t>(
serialization_map_->Lookup(Key(obj), Hash(obj), false)->value));
}
void AddMapping(HeapObject* obj, int to) {
ASSERT(!IsMapped(obj));
HashMap::Entry* entry =
serialization_map_->Lookup(Key(obj), Hash(obj), true);
entry->value = Value(to);
}
private:
static bool SerializationMatchFun(void* key1, void* key2) {
return key1 == key2;
}
static uint32_t Hash(HeapObject* obj) {
return static_cast<int32_t>(reinterpret_cast<intptr_t>(obj->address()));
}
static void* Key(HeapObject* obj) {
return reinterpret_cast<void*>(obj->address());
}
static void* Value(int v) {
return reinterpret_cast<void*>(v);
}
HashMap* serialization_map_;
AssertNoAllocation* no_allocation_;
DISALLOW_COPY_AND_ASSIGN(SerializationAddressMapper);
};
// There can be only one serializer per V8 process.
class Serializer : public SerializerDeserializer {
public:
explicit Serializer(SnapshotByteSink* sink);
~Serializer();
void VisitPointers(Object** start, Object** end);
// You can call this after serialization to find out how much space was used
// in each space.
int CurrentAllocationAddress(int space) {
if (SpaceIsLarge(space)) return large_object_total_;
return fullness_[space];
}
static void Enable() {
if (!serialization_enabled_) {
ASSERT(!too_late_to_enable_now_);
}
serialization_enabled_ = true;
}
static void Disable() { serialization_enabled_ = false; }
// Call this when you have made use of the fact that there is no serialization
// going on.
static void TooLateToEnableNow() { too_late_to_enable_now_ = true; }
static bool enabled() { return serialization_enabled_; }
SerializationAddressMapper* address_mapper() { return &address_mapper_; }
void PutRoot(
int index, HeapObject* object, HowToCode how, WhereToPoint where);
#ifdef DEBUG
virtual void Synchronize(const char* tag);
#endif
protected:
static const int kInvalidRootIndex = -1;
int RootIndex(HeapObject* heap_object);
virtual bool ShouldBeInThePartialSnapshotCache(HeapObject* o) = 0;
intptr_t root_index_wave_front() { return root_index_wave_front_; }
void set_root_index_wave_front(intptr_t value) {
ASSERT(value >= root_index_wave_front_);
root_index_wave_front_ = value;
}
class ObjectSerializer : public ObjectVisitor {
public:
ObjectSerializer(Serializer* serializer,
Object* o,
SnapshotByteSink* sink,
HowToCode how_to_code,
WhereToPoint where_to_point)
: serializer_(serializer),
object_(HeapObject::cast(o)),
sink_(sink),
reference_representation_(how_to_code + where_to_point),
bytes_processed_so_far_(0) { }
void Serialize();
void VisitPointers(Object** start, Object** end);
void VisitEmbeddedPointer(RelocInfo* target);
void VisitExternalReferences(Address* start, Address* end);
void VisitExternalReference(RelocInfo* rinfo);
void VisitCodeTarget(RelocInfo* target);
void VisitCodeEntry(Address entry_address);
void VisitGlobalPropertyCell(RelocInfo* rinfo);
void VisitRuntimeEntry(RelocInfo* reloc);
// Used for seralizing the external strings that hold the natives source.
void VisitExternalAsciiString(
v8::String::ExternalAsciiStringResource** resource);
// We can't serialize a heap with external two byte strings.
void VisitExternalTwoByteString(
v8::String::ExternalStringResource** resource) {
UNREACHABLE();
}
private:
void OutputRawData(Address up_to);
Serializer* serializer_;
HeapObject* object_;
SnapshotByteSink* sink_;
int reference_representation_;
int bytes_processed_so_far_;
};
virtual void SerializeObject(Object* o,
HowToCode how_to_code,
WhereToPoint where_to_point) = 0;
void SerializeReferenceToPreviousObject(
int space,
int address,
HowToCode how_to_code,
WhereToPoint where_to_point);
void InitializeAllocators();
// This will return the space for an object. If the object is in large
// object space it may return kLargeCode or kLargeFixedArray in order
// to indicate to the deserializer what kind of large object allocation
// to make.
static int SpaceOfObject(HeapObject* object);
// This just returns the space of the object. It will return LO_SPACE
// for all large objects since you can't check the type of the object
// once the map has been used for the serialization address.
static int SpaceOfAlreadySerializedObject(HeapObject* object);
int Allocate(int space, int size, bool* new_page_started);
int EncodeExternalReference(Address addr) {
return external_reference_encoder_->Encode(addr);
}
// Keep track of the fullness of each space in order to generate
// relative addresses for back references. Large objects are
// just numbered sequentially since relative addresses make no
// sense in large object space.
int fullness_[LAST_SPACE + 1];
SnapshotByteSink* sink_;
int current_root_index_;
ExternalReferenceEncoder* external_reference_encoder_;
static bool serialization_enabled_;
// Did we already make use of the fact that serialization was not enabled?
static bool too_late_to_enable_now_;
int large_object_total_;
SerializationAddressMapper address_mapper_;
intptr_t root_index_wave_front_;
friend class ObjectSerializer;
friend class Deserializer;
DISALLOW_COPY_AND_ASSIGN(Serializer);
};
class PartialSerializer : public Serializer {
public:
PartialSerializer(Serializer* startup_snapshot_serializer,
SnapshotByteSink* sink)
: Serializer(sink),
startup_serializer_(startup_snapshot_serializer) {
set_root_index_wave_front(Heap::kStrongRootListLength);
}
// Serialize the objects reachable from a single object pointer.
virtual void Serialize(Object** o);
virtual void SerializeObject(Object* o,
HowToCode how_to_code,
WhereToPoint where_to_point);
protected:
virtual int PartialSnapshotCacheIndex(HeapObject* o);
virtual bool ShouldBeInThePartialSnapshotCache(HeapObject* o) {
// Scripts should be referred only through shared function infos. We can't
// allow them to be part of the partial snapshot because they contain a
// unique ID, and deserializing several partial snapshots containing script
// would cause dupes.
ASSERT(!o->IsScript());
return o->IsString() || o->IsSharedFunctionInfo() ||
o->IsHeapNumber() || o->IsCode() ||
o->IsScopeInfo() ||
o->map() == HEAP->fixed_cow_array_map();
}
private:
Serializer* startup_serializer_;
DISALLOW_COPY_AND_ASSIGN(PartialSerializer);
};
class StartupSerializer : public Serializer {
public:
explicit StartupSerializer(SnapshotByteSink* sink) : Serializer(sink) {
// Clear the cache of objects used by the partial snapshot. After the
// strong roots have been serialized we can create a partial snapshot
// which will repopulate the cache with objects needed by that partial
// snapshot.
Isolate::Current()->set_serialize_partial_snapshot_cache_length(0);
}
// Serialize the current state of the heap. The order is:
// 1) Strong references.
// 2) Partial snapshot cache.
// 3) Weak references (eg the symbol table).
virtual void SerializeStrongReferences();
virtual void SerializeObject(Object* o,
HowToCode how_to_code,
WhereToPoint where_to_point);
void SerializeWeakReferences();
void Serialize() {
SerializeStrongReferences();
SerializeWeakReferences();
}
private:
virtual bool ShouldBeInThePartialSnapshotCache(HeapObject* o) {
return false;
}
};
} } // namespace v8::internal
#endif // V8_SERIALIZE_H_