Extend the maximum size map space...

src/objects.h

 // 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
@@ skipping 874 matching lines @@
   // mark an object as live and/or overflowed:
   //   last bit = 0, marked as alive
   //   second bit = 1, overflowed
   // An object is only marked as overflowed when it is marked as live while
   // the marking stack is overflowed.
   static const int kMarkingBit = 0;  // marking bit
   static const int kMarkingMask = (1 << kMarkingBit);  // marking mask
   static const int kOverflowBit = 1;  // overflow bit
   static const int kOverflowMask = (1 << kOverflowBit);  // overflow mask
 
-  // Forwarding pointers and map pointer encoding
-  //  31             21 20              10 9               0
+  // Forwarding pointers and map pointer encoding. On 32 bit all the bits are
+  // used.
   // +-----------------+------------------+-----------------+
   // |forwarding offset|page offset of map|page index of map|
   // +-----------------+------------------+-----------------+
-  //  11 bits           11 bits            10 bits
-  static const int kMapPageIndexBits = 10;
-  static const int kMapPageOffsetBits = 11;
-  static const int kForwardingOffsetBits = 11;
+  //          ^                 ^                  ^
+  //          |                 |                  |
+  //          |                 |          kMapPageIndexBits
+  //          |         kMapPageOffsetBits
+  // kForwardingOffsetBits
+  static const int kMapPageOffsetBits = kPageSizeBits - kMapAlignmentBits;
+  static const int kForwardingOffsetBits = kPageSizeBits - kObjectAlignmentBits;
+#ifdef V8_HOST_ARCH_64_BIT
+  static const int kMapPageIndexBits = 16;
+#else
+  // Use all the 32-bits to encode on a 32-bit platform.
+  static const int kMapPageIndexBits =
+      32 - (kMapPageOffsetBits + kForwardingOffsetBits);
+#endif
 
   static const int kMapPageIndexShift = 0;
   static const int kMapPageOffsetShift =
       kMapPageIndexShift + kMapPageIndexBits;
   static const int kForwardingOffsetShift =
       kMapPageOffsetShift + kMapPageOffsetBits;
 
-  // 0x000003FF
-  static const uint32_t kMapPageIndexMask =
+  // Bit masks covering the different parts the encoding.
+  static const uintptr_t kMapPageIndexMask =
       (1 << kMapPageOffsetShift) - 1;
-
-  // 0x001FFC00
-  static const uint32_t kMapPageOffsetMask =
+  static const uintptr_t kMapPageOffsetMask =
       ((1 << kForwardingOffsetShift) - 1) & ~kMapPageIndexMask;
-
-  // 0xFFE00000
-  static const uint32_t kForwardingOffsetMask =
+  static const uintptr_t kForwardingOffsetMask =
       ~(kMapPageIndexMask | kMapPageOffsetMask);
 
  private:
   // HeapObject calls the private constructor and directly reads the value.
   friend class HeapObject;
 
   explicit MapWord(uintptr_t value) : value_(value) {}
 
   uintptr_t value_;
 };
@@ skipping 1900 matching lines @@
 
   // [constructor]: points back to the function responsible for this map.
   DECL_ACCESSORS(constructor, Object)
 
   // [instance descriptors]: describes the object.
   DECL_ACCESSORS(instance_descriptors, DescriptorArray)
 
   // [stub cache]: contains stubs compiled for this map.
   DECL_ACCESSORS(code_cache, FixedArray)
 
-  // Returns a copy of the map.
   Object* CopyDropDescriptors();
 
   // Returns a copy of the map, with all transitions dropped from the
   // instance descriptors.
   Object* CopyDropTransitions();
 
   // Returns the property index for name (only valid for FAST MODE).
   int PropertyIndexFor(String* name);
 
   // Returns the next free property index (only valid for FAST MODE).
@@ skipping 47 matching lines @@
   static const int kMaxPreAllocatedPropertyFields = 255;
 
   // Layout description.
   static const int kInstanceSizesOffset = HeapObject::kHeaderSize;
   static const int kInstanceAttributesOffset = kInstanceSizesOffset + kIntSize;
   static const int kPrototypeOffset = kInstanceAttributesOffset + kIntSize;
   static const int kConstructorOffset = kPrototypeOffset + kPointerSize;
   static const int kInstanceDescriptorsOffset =
       kConstructorOffset + kPointerSize;
   static const int kCodeCacheOffset = kInstanceDescriptorsOffset + kPointerSize;
-  static const int kSize = kCodeCacheOffset + kPointerSize;
+  static const int kPadStart = kCodeCacheOffset + kPointerSize;
+  static const int kSize = MAP_SIZE_ALIGN(kPadStart);
 
   // Byte offsets within kInstanceSizesOffset.
   static const int kInstanceSizeOffset = kInstanceSizesOffset + 0;
   static const int kInObjectPropertiesByte = 1;
   static const int kInObjectPropertiesOffset =
       kInstanceSizesOffset + kInObjectPropertiesByte;
   static const int kPreAllocatedPropertyFieldsByte = 2;
   static const int kPreAllocatedPropertyFieldsOffset =
       kInstanceSizesOffset + kPreAllocatedPropertyFieldsByte;
   // The byte at position 3 is not in use at the moment.
@@ skipping 1943 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_