MIPS: Swap bitfield3 and backpointer.

src/mips/macro-assembler-mips.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 5272 matching lines @@
   And(bitmap_scratch, bitmap_scratch, Operand(~Page::kPageAlignmentMask));
   lw(t8, MemOperand(bitmap_scratch, MemoryChunk::kLiveBytesOffset));
   Addu(t8, t8, Operand(length));
   sw(t8, MemOperand(bitmap_scratch, MemoryChunk::kLiveBytesOffset));
 
   bind(&done);
 }
 
 
 void MacroAssembler::LoadInstanceDescriptors(Register map,
-                                             Register descriptors) {
+                                             Register descriptors,
+                                             Register scratch) {
   lw(descriptors,
-     FieldMemOperand(map, Map::kInstanceDescriptorsOrBitField3Offset));
-  Label not_smi;
-  JumpIfNotSmi(descriptors, &not_smi);
+     FieldMemOperand(map, Map::kInstanceDescriptorsOrBackPointerOffset));
+
+  Label ok, fail;
+  CheckMap(descriptors,
+           scratch,
+           isolate()->factory()->fixed_array_map(),
+           &fail,
+           DONT_DO_SMI_CHECK);
+  jmp(&ok);
+  bind(&fail);
   LoadRoot(descriptors, Heap::kEmptyDescriptorArrayRootIndex);
-  bind(&not_smi);
+  bind(&ok);
 }
 
 
 void MacroAssembler::CheckEnumCache(Register null_value, Label* call_runtime) {
   Label next;
   // Preload a couple of values used in the loop.
   Register  empty_fixed_array_value = t2;
   LoadRoot(empty_fixed_array_value, Heap::kEmptyFixedArrayRootIndex);
   Register empty_descriptor_array_value = t3;
   LoadRoot(empty_descriptor_array_value,
            Heap::kEmptyDescriptorArrayRootIndex);
   mov(a1, a0);
   bind(&next);
 
   // Check that there are no elements.  Register a1 contains the
   // current JS object we've reached through the prototype chain.
   lw(a2, FieldMemOperand(a1, JSObject::kElementsOffset));
   Branch(call_runtime, ne, a2, Operand(empty_fixed_array_value));
 
   // Check that instance descriptors are not empty so that we can
   // check for an enum cache.  Leave the map in a2 for the subsequent
   // prototype load.
   lw(a2, FieldMemOperand(a1, HeapObject::kMapOffset));
-  lw(a3, FieldMemOperand(a2, Map::kInstanceDescriptorsOrBitField3Offset));
-  JumpIfSmi(a3, call_runtime);
+  lw(a3, FieldMemOperand(a2, Map::kInstanceDescriptorsOrBackPointerOffset));
+
+  CheckMap(a3,
+           t3,
+           isolate()->factory()->fixed_array_map(),
+           call_runtime,
+           DONT_DO_SMI_CHECK);
 
   // Check that there is an enum cache in the non-empty instance
   // descriptors (a3).  This is the case if the next enumeration
   // index field does not contain a smi.
   lw(a3, FieldMemOperand(a3, DescriptorArray::kEnumerationIndexOffset));
   JumpIfSmi(a3, call_runtime);
 
   // For all objects but the receiver, check that the cache is empty.
   Label check_prototype;
   Branch(&check_prototype, eq, a1, Operand(a0));
@@ skipping 111 matching lines @@
        opcode == BGTZL);
   opcode = (cond == eq) ? BEQ : BNE;
   instr = (instr & ~kOpcodeMask) | opcode;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_MIPS