Make object accessors more const-correct.

src/spaces.h

 // Copyright 2011 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_SPACES_H_
 #define V8_SPACES_H_
 
 #include "src/allocation.h"
 #include "src/base/atomicops.h"
 #include "src/hashmap.h"
@@ skipping 265 matching lines @@
 // MemoryChunk represents a memory region owned by a specific space.
 // It is divided into the header and the body. Chunk start is always
 // 1MB aligned. Start of the body is aligned so it can accommodate
 // any heap object.
 class MemoryChunk {
  public:
   // Only works if the pointer is in the first kPageSize of the MemoryChunk.
   static MemoryChunk* FromAddress(Address a) {
     return reinterpret_cast<MemoryChunk*>(OffsetFrom(a) & ~kAlignmentMask);
   }
+  static const MemoryChunk* FromAddress(const byte* a) {
+    return reinterpret_cast<const MemoryChunk*>(
+        OffsetFrom(a) & ~kAlignmentMask);
+  }
 
   // Only works for addresses in pointer spaces, not data or code spaces.
   static inline MemoryChunk* FromAnyPointerAddress(Heap* heap, Address addr);
 
   Address address() { return reinterpret_cast<Address>(this); }
 
   bool is_valid() { return address() != NULL; }
 
   MemoryChunk* next_chunk() const {
     return reinterpret_cast<MemoryChunk*>(base::Acquire_Load(&next_chunk_));
@@ skipping 324 matching lines @@
     return static_cast<uint32_t>(offset) >> kPointerSizeLog2;
   }
 
   inline Address MarkbitIndexToAddress(uint32_t index) {
     return this->address() + (index << kPointerSizeLog2);
   }
 
   void InsertAfter(MemoryChunk* other);
   void Unlink();
 
-  inline Heap* heap() { return heap_; }
+  inline Heap* heap() const { return heap_; }
 
   static const int kFlagsOffset = kPointerSize;
 
   bool IsEvacuationCandidate() { return IsFlagSet(EVACUATION_CANDIDATE); }
 
   bool ShouldSkipEvacuationSlotRecording() {
     return (flags_ & kSkipEvacuationSlotsRecordingMask) != 0;
   }
 
   inline SkipList* skip_list() {
@@ skipping 2359 matching lines @@
   }
   // Must be small, since an iteration is used for lookup.
   static const int kMaxComments = 64;
 };
 #endif
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_SPACES_H_