Fix debug printing of pointers, and a keyed store with smi index error, in X6...

src/x64/ic-x64.cc

 // Copyright 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 406 matching lines @@
   // Check that the receiver does not require access checks.  We need
   // to do this because this generic stub does not perform map checks.
   __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
            Immediate(1 << Map::kIsAccessCheckNeeded));
   __ j(not_zero, &slow);
   // Get the key from the stack.
   __ movq(rbx, Operand(rsp, 1 * kPointerSize));  // 1 ~ return address
   // Check that the key is a smi.
   __ testl(rbx, Immediate(kSmiTagMask));
   __ j(not_zero, &slow);
+  // If it is a smi, make sure it is zero-extended, so it can be
+  // used as an index in a memory operand.
+  __ movl(rbx, rbx);  // Clear the high bits of rbx.
 
   __ CmpInstanceType(rcx, JS_ARRAY_TYPE);
   __ j(equal, &array);
   // Check that the object is some kind of JS object.
   __ CmpInstanceType(rcx, FIRST_JS_OBJECT_TYPE);
   __ j(below, &slow);
 
   // Object case: Check key against length in the elements array.
   // rax: value
   // rdx: JSObject
-  // rbx: index (as a smi)
+  // rbx: index (as a smi), zero-extended.
   __ movq(rcx, FieldOperand(rdx, JSObject::kElementsOffset));
   // Check that the object is in fast mode (not dictionary).
   __ Cmp(FieldOperand(rcx, HeapObject::kMapOffset), Factory::fixed_array_map());
   __ j(not_equal, &slow);
   // Untag the key (for checking against untagged length in the fixed array).
   __ movl(rdx, rbx);
   __ sarl(rdx, Immediate(kSmiTagSize));
   __ cmpl(rdx, FieldOperand(rcx, Array::kLengthOffset));
   // rax: value
   // rcx: FixedArray
@@ skipping 267 matching lines @@
 
 void StoreIC::GenerateMegamorphic(MacroAssembler* masm) {
   Generate(masm, ExternalReference(IC_Utility(kStoreIC_Miss)));
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal