Use root array to load roots in generated ARM code....

src/heap.h

 // Copyright 2006-2008 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 713 matching lines @@
   }
 
   // Sets the non_monomorphic_cache_ (only used when expanding the dictionary).
   static void public_set_non_monomorphic_cache(NumberDictionary* value) {
     roots_[kNonMonomorphicCacheRootIndex] = value;
   }
 
   // Update the next script id.
   static inline void SetLastScriptId(Object* last_script_id);
 
+  // Generated code can embed this address to get access to the roots.
+  static Object** roots_address() { return roots_; }
+
 #ifdef DEBUG
   static void Print();
   static void PrintHandles();
 
   // Verify the heap is in its normal state before or after a GC.
   static void Verify();
 
   // Report heap statistics.
   static void ReportHeapStatistics(const char* title);
   static void ReportCodeStatistics(const char* title);
@@ skipping 86 matching lines @@
            > old_gen_promotion_limit_;
   }
 
   // True if we have reached the allocation limit in the old generation that
   // should artificially cause a GC right now.
   static bool OldGenerationAllocationLimitReached() {
     return (PromotedSpaceSize() + PromotedExternalMemorySize())
            > old_gen_allocation_limit_;
   }
 
+  // Declare all the root indices.
+  enum RootListIndex {
+#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
+    STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
+#undef ROOT_INDEX_DECLARATION
+
+// Utility type maps
+#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
+  STRUCT_LIST(DECLARE_STRUCT_MAP)
+#undef DECLARE_STRUCT_MAP
+
+#define SYMBOL_INDEX_DECLARATION(name, str) k##name##RootIndex,
+    SYMBOL_LIST(SYMBOL_INDEX_DECLARATION)
+#undef SYMBOL_DECLARATION
+
+    kSymbolTableRootIndex,
+    kStrongRootListLength = kSymbolTableRootIndex,
+    kRootListLength
+  };
+
  private:
   static int semispace_size_;
   static int initial_semispace_size_;
   static int young_generation_size_;
   static int old_generation_size_;
 
   // For keeping track of how much data has survived
   // scavenge since last new space expansion.
   static int survived_since_last_expansion_;
 
@@ skipping 60 matching lines @@
   // by global handles
   static int amount_of_external_allocated_memory_;
 
   // Caches the amount of external memory registered at the last global gc.
   static int amount_of_external_allocated_memory_at_last_global_gc_;
 
   // Indicates that an allocation has failed in the old generation since the
   // last GC.
   static int old_gen_exhausted_;
 
-  // Declare all the root indices.
-  enum RootListIndex {
-#define ROOT_INDEX_DECLARATION(type, name, camel_name) k##camel_name##RootIndex,
-    STRONG_ROOT_LIST(ROOT_INDEX_DECLARATION)
-#undef ROOT_INDEX_DECLARATION
-
-// Utility type maps
-#define DECLARE_STRUCT_MAP(NAME, Name, name) k##Name##MapRootIndex,
-  STRUCT_LIST(DECLARE_STRUCT_MAP)
-#undef DECLARE_STRUCT_MAP
-
-#define SYMBOL_INDEX_DECLARATION(name, str) k##name##RootIndex,
-    SYMBOL_LIST(SYMBOL_INDEX_DECLARATION)
-#undef SYMBOL_DECLARATION
-
-    kSymbolTableRootIndex,
-    kStrongRootListLength = kSymbolTableRootIndex,
-    kRootListLength
-  };
-
   static Object* roots_[kRootListLength];
 
   struct StringTypeTable {
     InstanceType type;
     int size;
     RootListIndex index;
   };
 
   struct ConstantSymbolTable {
     const char* contents;
@@ skipping 517 matching lines @@
   int marked_count_;
 
   // The count from the end of the previous full GC.  Will be zero if there
   // was no previous full GC.
   int previous_marked_count_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_