Fix DoubleStackSlot-to-DoubleStackSlot moves on ia32. Unify platform-independent code.

src/lithium.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 239 matching lines @@
     case FAST_HOLEY_ELEMENTS:
     case DICTIONARY_ELEMENTS:
     case NON_STRICT_ARGUMENTS_ELEMENTS:
       return kPointerSizeLog2;
   }
   UNREACHABLE();
   return 0;
 }
 
 
+int StackSlotOffset(int index) {
+  if (index >= 0) {
+    // Local or spill slot. Skip the frame pointer, function, and
+    // context in the fixed part of the frame.
+    return -(index + 3) * kPointerSize;
+  } else {
+    // Incoming parameter. Skip the return address.
+    return -(index - 1) * kPointerSize;
+  }
+}
+
+
 LChunk::LChunk(CompilationInfo* info, HGraph* graph)
     : spill_slot_count_(0),
       info_(info),
       graph_(graph),
       instructions_(32, graph->zone()),
       pointer_maps_(8, graph->zone()),
       inlined_closures_(1, graph->zone()) {
 }
 
 
@@ skipping 218 matching lines @@
       } else {
         spill_slot_count_++;
       }
     }
     iterator.Advance();
   }
 }
 
 
 } }  // namespace v8::internal