Move RootIndexMap out of serializer file.

src/address-map.h

+// Copyright 2015 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_ADDRESS_MAP_H_
+#define V8_ADDRESS_MAP_H_
+
+#include "src/assert-scope.h"
+#include "src/hashmap.h"
+#include "src/objects.h"
+
+namespace v8 {
+namespace internal {
+
+class AddressMapBase {
+ protected:
+  static void SetValue(HashMap::Entry* entry, uint32_t v) {
+    entry->value = reinterpret_cast<void*>(v);
+  }
+
+  static uint32_t GetValue(HashMap::Entry* entry) {
+    return static_cast<uint32_t>(reinterpret_cast<intptr_t>(entry->value));
+  }
+
+  inline static HashMap::Entry* LookupEntry(HashMap* map, HeapObject* obj,
+                                            bool insert) {
+    if (insert) {
+      map->LookupOrInsert(Key(obj), Hash(obj));
+    }
+    return map->Lookup(Key(obj), Hash(obj));
+  }
+
+ private:
+  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());
+  }
+};
+
+
+class RootIndexMap : public AddressMapBase {
+ public:
+  explicit RootIndexMap(Isolate* isolate);
+
+  static const int kInvalidRootIndex = -1;
+
+  int Lookup(HeapObject* obj) {
+    HashMap::Entry* entry = LookupEntry(map_, obj, false);
+    if (entry) return GetValue(entry);
+    return kInvalidRootIndex;
+  }
+
+ private:
+  HashMap* map_;
+
+  DISALLOW_COPY_AND_ASSIGN(RootIndexMap);
+};
+
+
+class BackReference {
+ public:
+  explicit BackReference(uint32_t bitfield) : bitfield_(bitfield) {}
+
+  BackReference() : bitfield_(kInvalidValue) {}
+
+  static BackReference SourceReference() { return BackReference(kSourceValue); }
+
+  static BackReference GlobalProxyReference() {
+    return BackReference(kGlobalProxyValue);
+  }
+
+  static BackReference LargeObjectReference(uint32_t index) {
+    return BackReference(SpaceBits::encode(LO_SPACE) |
+                         ChunkOffsetBits::encode(index));
+  }
+
+  static BackReference DummyReference() { return BackReference(kDummyValue); }
+
+  static BackReference Reference(AllocationSpace space, uint32_t chunk_index,
+                                 uint32_t chunk_offset) {
+    DCHECK(IsAligned(chunk_offset, kObjectAlignment));
+    DCHECK_NE(LO_SPACE, space);
+    return BackReference(
+        SpaceBits::encode(space) | ChunkIndexBits::encode(chunk_index) |
+        ChunkOffsetBits::encode(chunk_offset >> kObjectAlignmentBits));
+  }
+
+  bool is_valid() const { return bitfield_ != kInvalidValue; }
+  bool is_source() const { return bitfield_ == kSourceValue; }
+  bool is_global_proxy() const { return bitfield_ == kGlobalProxyValue; }
+
+  AllocationSpace space() const {
+    DCHECK(is_valid());
+    return SpaceBits::decode(bitfield_);
+  }
+
+  uint32_t chunk_offset() const {
+    DCHECK(is_valid());
+    return ChunkOffsetBits::decode(bitfield_) << kObjectAlignmentBits;
+  }
+
+  uint32_t large_object_index() const {
+    DCHECK(is_valid());
+    DCHECK(chunk_index() == 0);
+    return ChunkOffsetBits::decode(bitfield_);
+  }
+
+  uint32_t chunk_index() const {
+    DCHECK(is_valid());
+    return ChunkIndexBits::decode(bitfield_);
+  }
+
+  uint32_t reference() const {
+    DCHECK(is_valid());
+    return bitfield_ & (ChunkOffsetBits::kMask | ChunkIndexBits::kMask);
+  }
+
+  uint32_t bitfield() const { return bitfield_; }
+
+ private:
+  static const uint32_t kInvalidValue = 0xFFFFFFFF;
+  static const uint32_t kSourceValue = 0xFFFFFFFE;
+  static const uint32_t kGlobalProxyValue = 0xFFFFFFFD;
+  static const uint32_t kDummyValue = 0xFFFFFFFC;
+  static const int kChunkOffsetSize = kPageSizeBits - kObjectAlignmentBits;
+  static const int kChunkIndexSize = 32 - kChunkOffsetSize - kSpaceTagSize;
+
+ public:
+  static const int kMaxChunkIndex = (1 << kChunkIndexSize) - 1;
+
+ private:
+  class ChunkOffsetBits : public BitField<uint32_t, 0, kChunkOffsetSize> {};
+  class ChunkIndexBits
+      : public BitField<uint32_t, ChunkOffsetBits::kNext, kChunkIndexSize> {};
+  class SpaceBits
+      : public BitField<AllocationSpace, ChunkIndexBits::kNext, kSpaceTagSize> {
+  };
+
+  uint32_t bitfield_;
+};
+
+
+// Mapping objects to their location after deserialization.
+// This is used during building, but not at runtime by V8.
+class BackReferenceMap : public AddressMapBase {
+ public:
+  BackReferenceMap()
+      : no_allocation_(), map_(new HashMap(HashMap::PointersMatch)) {}
+
+  ~BackReferenceMap() { delete map_; }
+
+  BackReference Lookup(HeapObject* obj) {
+    HashMap::Entry* entry = LookupEntry(map_, obj, false);
+    return entry ? BackReference(GetValue(entry)) : BackReference();
+  }
+
+  void Add(HeapObject* obj, BackReference b) {
+    DCHECK(b.is_valid());
+    DCHECK_NULL(LookupEntry(map_, obj, false));
+    HashMap::Entry* entry = LookupEntry(map_, obj, true);
+    SetValue(entry, b.bitfield());
+  }
+
+  void AddSourceString(String* string) {
+    Add(string, BackReference::SourceReference());
+  }
+
+  void AddGlobalProxy(HeapObject* global_proxy) {
+    Add(global_proxy, BackReference::GlobalProxyReference());
+  }
+
+ private:
+  DisallowHeapAllocation no_allocation_;
+  HashMap* map_;
+  DISALLOW_COPY_AND_ASSIGN(BackReferenceMap);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_ADDRESS_MAP_H_