X64: Add inline SwapElements to fundamental code generator on x64 platform.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
===================================================================
--- src/x64/full-codegen-x64.cc	(revision 6979)
+++ src/x64/full-codegen-x64.cc	(working copy)
@@ -2969,7 +2969,73 @@
   VisitForStackValue(args->at(0));
   VisitForStackValue(args->at(1));
   VisitForStackValue(args->at(2));
+  Label done;
+  Label slow_case;
+  Register object = rax;
+  Register index_1 = rbx;
+  Register index_2 = rcx;
+  Register elements = rdi;
+  Register temp = rdx;
+  __ movq(object, Operand(rsp, 2 * kPointerSize));
+  // Fetch the map and check if array is in fast case.
+  // Check that object doesn't require security checks and
+  // has no indexed interceptor.
+  __ CmpObjectType(object, FIRST_JS_OBJECT_TYPE, temp);
+  __ j(below, &slow_case);
+  __ testb(FieldOperand(temp, Map::kBitFieldOffset),
+           Immediate(KeyedLoadIC::kSlowCaseBitFieldMask));
+  __ j(not_zero, &slow_case);
+
+  // Check the object's elements are in fast case and writable.
+  __ movq(elements, FieldOperand(object, JSObject::kElementsOffset));
+  __ CompareRoot(FieldOperand(elements, HeapObject::kMapOffset),
+                 Heap::kFixedArrayMapRootIndex);
+  __ j(not_equal, &slow_case);
+
+  // Check that both indices are smis.
+  __ movq(index_1, Operand(rsp, 1 * kPointerSize));
+  __ movq(index_2, Operand(rsp, 0 * kPointerSize));
+  __ JumpIfNotBothSmi(index_1, index_2, &slow_case);
+
+  // Check that both indices are valid.
+  // The JSArray length field is a smi since the array is in fast case mode.
+  __ movq(temp, FieldOperand(object, JSArray::kLengthOffset));
+  __ SmiCompare(temp, index_1);
+  __ j(below_equal, &slow_case);
+  __ SmiCompare(temp, index_2);
+  __ j(below_equal, &slow_case);
+
+  __ SmiToInteger32(index_1, index_1);
+  __ SmiToInteger32(index_2, index_2);
+  // Bring addresses into index1 and index2.
+  __ lea(index_1, FieldOperand(elements, index_1, times_pointer_size,
+                               FixedArray::kHeaderSize));
+  __ lea(index_2, FieldOperand(elements, index_2, times_pointer_size,
+                               FixedArray::kHeaderSize));
+
+  // Swap elements.  Use object and temp as scratch registers.
+  __ movq(object, Operand(index_1, 0));
+  __ movq(temp,   Operand(index_2, 0));
+  __ movq(Operand(index_2, 0), object);
+  __ movq(Operand(index_1, 0), temp);
+
+  Label new_space;
+  __ InNewSpace(elements, temp, equal, &new_space);
+
+  __ movq(object, elements);
+  __ RecordWriteHelper(object, index_1, temp);
+  __ RecordWriteHelper(elements, index_2, temp);
+
+  __ bind(&new_space);
+  // We are done. Drop elements from the stack, and return undefined.
+  __ addq(rsp, Immediate(3 * kPointerSize));
+  __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+  __ jmp(&done);
+
+  __ bind(&slow_case);
   __ CallRuntime(Runtime::kSwapElements, 3);
+
+  __ bind(&done);
   context()->Plug(rax);
 }