Correct handling of arrays with callbacks in the prototype chain.

src/arm/macro-assembler-arm.cc

 // Copyright 2012 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 3910 matching lines @@
   for (int i = 0; i < Register::NumAllocatableRegisters(); i++) {
     Register candidate = Register::FromAllocationIndex(i);
     if (regs & candidate.bit()) continue;
     return candidate;
   }
   UNREACHABLE();
   return no_reg;
 }
 
 
+void MacroAssembler::JumpIfDictionaryInPrototypeChain(
+    Register object,
+    Register scratch0,
+    Register scratch1,
+    Label* found) {
+  ASSERT(!scratch1.is(scratch0));
+  Factory* factory = isolate()->factory();
+  Register current = scratch0;
+  Label loop_again;
+
+  // scratch contained elements pointer.
+  mov(current, object);
+
+  // Loop based on the map going up the prototype chain.
+  bind(&loop_again);
+  ldr(current, FieldMemOperand(current, HeapObject::kMapOffset));
+  ldr(scratch1, FieldMemOperand(current, Map::kBitField2Offset));
+  Ubfx(scratch1, scratch1, Map::kElementsKindShift, Map::kElementsKindBitCount);
+  cmp(scratch1, Operand(DICTIONARY_ELEMENTS));
+  b(eq, found);
+  ldr(current, FieldMemOperand(current, Map::kPrototypeOffset));
+  cmp(current, Operand(factory->null_value()));
+  b(ne, &loop_again);
+}
+
+
 #ifdef DEBUG
 bool AreAliased(Register reg1,
                 Register reg2,
                 Register reg3,
                 Register reg4,
                 Register reg5,
                 Register reg6) {
   int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
     reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid();
 
@@ skipping 50 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM