[serializer] split up src/snapshot/serialize.*

src/snapshot/serializer-common.h

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_SNAPSHOT_SERIALIZER_COMMON_H_
+#define V8_SNAPSHOT_SERIALIZER_COMMON_H_
+
+#include "src/address-map.h"
+#include "src/globals.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+
+// 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);
+
+  int size() const { return refs_.length(); }
+  Address address(int i) { return refs_[i].address; }
+  const char* name(int i) { return refs_[i].name; }
+
+  inline static Address NotAvailable() { return NULL; }
+
+  static const int kDeoptTableSerializeEntryCount = 64;
+
+ private:
+  struct ExternalReferenceEntry {
+    Address address;
+    const char* name;
+  };
+
+  explicit ExternalReferenceTable(Isolate* isolate);
+
+  void Add(Address address, const char* name) {
+    ExternalReferenceEntry entry = {address, name};
+    refs_.Add(entry);
+  }
+
+  List<ExternalReferenceEntry> refs_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExternalReferenceTable);
+};
+
+class ExternalReferenceEncoder {
+ public:
+  explicit ExternalReferenceEncoder(Isolate* isolate);
+
+  uint32_t Encode(Address key) const;
+
+  const char* NameOfAddress(Isolate* isolate, Address address) const;
+
+ private:
+  static uint32_t Hash(Address key) {
+    return static_cast<uint32_t>(reinterpret_cast<uintptr_t>(key) >>
+                                 kPointerSizeLog2);
+  }
+
+  HashMap* map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExternalReferenceEncoder);
+};
+
+class HotObjectsList {
+ public:
+  HotObjectsList() : index_(0) {
+    for (int i = 0; i < kSize; i++) circular_queue_[i] = NULL;
+  }
+
+  void Add(HeapObject* object) {
+    circular_queue_[index_] = object;
+    index_ = (index_ + 1) & kSizeMask;
+  }
+
+  HeapObject* Get(int index) {
+    DCHECK_NOT_NULL(circular_queue_[index]);
+    return circular_queue_[index];
+  }
+
+  static const int kNotFound = -1;
+
+  int Find(HeapObject* object) {
+    for (int i = 0; i < kSize; i++) {
+      if (circular_queue_[i] == object) return i;
+    }
+    return kNotFound;
+  }
+
+  static const int kSize = 8;
+
+ private:
+  STATIC_ASSERT(IS_POWER_OF_TWO(kSize));
+  static const int kSizeMask = kSize - 1;
+  HeapObject* circular_queue_[kSize];
+  int index_;
+
+  DISALLOW_COPY_AND_ASSIGN(HotObjectsList);
+};
+
+// The Serializer/Deserializer class is a common superclass for Serializer and
+// Deserializer which is used to store common constants and methods used by
+// both.
+class SerializerDeserializer : public ObjectVisitor {
+ public:
+  static void Iterate(Isolate* isolate, ObjectVisitor* visitor);
+
+  // No reservation for large object space necessary.
+  static const int kNumberOfPreallocatedSpaces = LAST_PAGED_SPACE + 1;
+  static const int kNumberOfSpaces = LAST_SPACE + 1;
+
+ protected:
+  static bool CanBeDeferred(HeapObject* o);
+
+  // ---------- byte code range 0x00..0x7f ----------
+  // Byte codes in this range represent Where, HowToCode and WhereToPoint.
+  // Where the pointed-to object can be found:
+  // The static assert below will trigger when the number of preallocated spaces
+  // changed. If that happens, update the bytecode ranges in the comments below.
+  STATIC_ASSERT(5 == kNumberOfSpaces);
+  enum Where {
+    // 0x00..0x04  Allocate new object, in specified space.
+    kNewObject = 0,
+    // 0x05        Unused (including 0x25, 0x45, 0x65).
+    // 0x06        Unused (including 0x26, 0x46, 0x66).
+    // 0x07        Unused (including 0x27, 0x47, 0x67).
+    // 0x08..0x0c  Reference to previous object from space.
+    kBackref = 0x08,
+    // 0x0d        Unused (including 0x2d, 0x4d, 0x6d).
+    // 0x0e        Unused (including 0x2e, 0x4e, 0x6e).
+    // 0x0f        Unused (including 0x2f, 0x4f, 0x6f).
+    // 0x10..0x14  Reference to previous object from space after skip.
+    kBackrefWithSkip = 0x10,
+    // 0x15        Unused (including 0x35, 0x55, 0x75).
+    // 0x16        Unused (including 0x36, 0x56, 0x76).
+    // 0x17        Misc (including 0x37, 0x57, 0x77).
+    // 0x18        Root array item.
+    kRootArray = 0x18,
+    // 0x19        Object in the partial snapshot cache.
+    kPartialSnapshotCache = 0x19,
+    // 0x1a        External reference referenced by id.
+    kExternalReference = 0x1a,
+    // 0x1b        Object provided in the attached list.
+    kAttachedReference = 0x1b,
+    // 0x1c        Builtin code referenced by index.
+    kBuiltin = 0x1c
+    // 0x1d..0x1f  Misc (including 0x3d..0x3f, 0x5d..0x5f, 0x7d..0x7f)
+  };
+
+  static const int kWhereMask = 0x1f;
+  static const int kSpaceMask = 7;
+  STATIC_ASSERT(kNumberOfSpaces <= kSpaceMask + 1);
+
+  // How to code the pointer to the object.
+  enum HowToCode {
+    // Straight pointer.
+    kPlain = 0,
+    // A pointer inlined in code. What this means depends on the architecture.
+    kFromCode = 0x20
+  };
+
+  static const int kHowToCodeMask = 0x20;
+
+  // Where to point within the object.
+  enum WhereToPoint {
+    // Points to start of object
+    kStartOfObject = 0,
+    // Points to instruction in code object or payload of cell.
+    kInnerPointer = 0x40
+  };
+
+  static const int kWhereToPointMask = 0x40;
+
+  // ---------- Misc ----------
+  // Skip.
+  static const int kSkip = 0x1d;
+  // Internal reference encoded as offsets of pc and target from code entry.
+  static const int kInternalReference = 0x1e;
+  static const int kInternalReferenceEncoded = 0x1f;
+  // Do nothing, used for padding.
+  static const int kNop = 0x3d;
+  // Move to next reserved chunk.
+  static const int kNextChunk = 0x3e;
+  // Deferring object content.
+  static const int kDeferred = 0x3f;
+  // 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 = 0x5d;
+  // Used for the source code for compiled stubs, which is in the executable,
+  // but is referred to from external strings in the snapshot.
+  static const int kExtraNativesStringResource = 0x5e;
+  // 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 = 0x17;
+  // Repeats of variable length.
+  static const int kVariableRepeat = 0x37;
+  // Raw data of variable length.
+  static const int kVariableRawData = 0x57;
+  // Alignment prefixes 0x7d..0x7f
+  static const int kAlignmentPrefix = 0x7d;
+
+  // 0x77 unused
+
+  // ---------- byte code range 0x80..0xff ----------
+  // First 32 root array items.
+  static const int kNumberOfRootArrayConstants = 0x20;
+  // 0x80..0x9f
+  static const int kRootArrayConstants = 0x80;
+  // 0xa0..0xbf
+  static const int kRootArrayConstantsWithSkip = 0xa0;
+  static const int kRootArrayConstantsMask = 0x1f;
+
+  // 8 hot (recently seen or back-referenced) objects with optional skip.
+  static const int kNumberOfHotObjects = 0x08;
+  // 0xc0..0xc7
+  static const int kHotObject = 0xc0;
+  // 0xc8..0xcf
+  static const int kHotObjectWithSkip = 0xc8;
+  static const int kHotObjectMask = 0x07;
+
+  // 32 common raw data lengths.
+  static const int kNumberOfFixedRawData = 0x20;
+  // 0xd0..0xef
+  static const int kFixedRawData = 0xd0;
+  static const int kOnePointerRawData = kFixedRawData;
+  static const int kFixedRawDataStart = kFixedRawData - 1;
+
+  // 16 repeats lengths.
+  static const int kNumberOfFixedRepeat = 0x10;
+  // 0xf0..0xff
+  static const int kFixedRepeat = 0xf0;
+  static const int kFixedRepeatStart = kFixedRepeat - 1;
+
+  // ---------- special values ----------
+  static const int kAnyOldSpace = -1;
+
+  // Sentinel after a new object to indicate that double alignment is needed.
+  static const int kDoubleAlignmentSentinel = 0;
+
+  // Used as index for the attached reference representing the source object.
+  static const int kSourceObjectReference = 0;
+
+  // Used as index for the attached reference representing the global proxy.
+  static const int kGlobalProxyReference = 0;
+
+  // ---------- member variable ----------
+  HotObjectsList hot_objects_;
+};
+
+class SerializedData {
+ public:
+  class Reservation {
+   public:
+    explicit Reservation(uint32_t size)
+        : reservation_(ChunkSizeBits::encode(size)) {}
+
+    uint32_t chunk_size() const { return ChunkSizeBits::decode(reservation_); }
+    bool is_last() const { return IsLastChunkBits::decode(reservation_); }
+
+    void mark_as_last() { reservation_ |= IsLastChunkBits::encode(true); }
+
+   private:
+    uint32_t reservation_;
+  };
+
+  SerializedData(byte* data, int size)
+      : data_(data), size_(size), owns_data_(false) {}
+  SerializedData() : data_(NULL), size_(0), owns_data_(false) {}
+
+  ~SerializedData() {
+    if (owns_data_) DeleteArray<byte>(data_);
+  }
+
+  uint32_t GetMagicNumber() const { return GetHeaderValue(kMagicNumberOffset); }
+
+  class ChunkSizeBits : public BitField<uint32_t, 0, 31> {};
+  class IsLastChunkBits : public BitField<bool, 31, 1> {};
+
+  static uint32_t ComputeMagicNumber(ExternalReferenceTable* table) {
+    uint32_t external_refs = table->size();
+    return 0xC0DE0000 ^ external_refs;
+  }
+
+ protected:
+  void SetHeaderValue(int offset, uint32_t value) {
+    uint32_t* address = reinterpret_cast<uint32_t*>(data_ + offset);
+    memcpy(reinterpret_cast<uint32_t*>(address), &value, sizeof(value));
+  }
+
+  uint32_t GetHeaderValue(int offset) const {
+    uint32_t value;
+    memcpy(&value, reinterpret_cast<int*>(data_ + offset), sizeof(value));
+    return value;
+  }
+
+  void AllocateData(int size);
+
+  static uint32_t ComputeMagicNumber(Isolate* isolate) {
+    return ComputeMagicNumber(ExternalReferenceTable::instance(isolate));
+  }
+
+  void SetMagicNumber(Isolate* isolate) {
+    SetHeaderValue(kMagicNumberOffset, ComputeMagicNumber(isolate));
+  }
+
+  static const int kMagicNumberOffset = 0;
+
+  byte* data_;
+  int size_;
+  bool owns_data_;
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_SNAPSHOT_SERIALIZER_COMMON_H_