[builtins] Remove STRING_ADD_LEFT and STRING_ADD_RIGHT builtins.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 3ba34645ea1a56bdc7df6aafd925586a82877700..3f0dec1dd7dc165b25857418e0c2d01320439671 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -3243,91 +3243,6 @@ void FullCodeGenerator::EmitIsSimdValue(CallRuntime* expr) {
 }
 
 
-void FullCodeGenerator::EmitIsStringWrapperSafeForDefaultValueOf(
-    CallRuntime* expr) {
-  ZoneList<Expression*>* args = expr->arguments();
-  DCHECK(args->length() == 1);
-
-  VisitForAccumulatorValue(args->at(0));
-
-  Label materialize_true, materialize_false, skip_lookup;
-  Label* if_true = NULL;
-  Label* if_false = NULL;
-  Label* fall_through = NULL;
-  context()->PrepareTest(&materialize_true, &materialize_false,
-                         &if_true, &if_false, &fall_through);
-
-  __ AssertNotSmi(rax);
-
-  // Check whether this map has already been checked to be safe for default
-  // valueOf.
-  __ movp(rbx, FieldOperand(rax, HeapObject::kMapOffset));
-  __ testb(FieldOperand(rbx, Map::kBitField2Offset),
-           Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
-  __ j(not_zero, &skip_lookup);
-
-  // Check for fast case object. Generate false result for slow case object.
-  __ movp(rcx, FieldOperand(rax, JSObject::kPropertiesOffset));
-  __ movp(rcx, FieldOperand(rcx, HeapObject::kMapOffset));
-  __ CompareRoot(rcx, Heap::kHashTableMapRootIndex);
-  __ j(equal, if_false);
-
-  // Look for valueOf string in the descriptor array, and indicate false if
-  // found. Since we omit an enumeration index check, if it is added via a
-  // transition that shares its descriptor array, this is a false positive.
-  Label entry, loop, done;
-
-  // Skip loop if no descriptors are valid.
-  __ NumberOfOwnDescriptors(rcx, rbx);
-  __ cmpp(rcx, Immediate(0));
-  __ j(equal, &done);
-
-  __ LoadInstanceDescriptors(rbx, r8);
-  // rbx: descriptor array.
-  // rcx: valid entries in the descriptor array.
-  // Calculate the end of the descriptor array.
-  __ imulp(rcx, rcx, Immediate(DescriptorArray::kDescriptorSize));
-  __ leap(rcx,
-          Operand(r8, rcx, times_pointer_size, DescriptorArray::kFirstOffset));
-  // Calculate location of the first key name.
-  __ addp(r8, Immediate(DescriptorArray::kFirstOffset));
-  // Loop through all the keys in the descriptor array. If one of these is the
-  // internalized string "valueOf" the result is false.
-  __ jmp(&entry);
-  __ bind(&loop);
-  __ movp(rdx, FieldOperand(r8, 0));
-  __ CompareRoot(rdx, Heap::kvalueOf_stringRootIndex);
-  __ j(equal, if_false);
-  __ addp(r8, Immediate(DescriptorArray::kDescriptorSize * kPointerSize));
-  __ bind(&entry);
-  __ cmpp(r8, rcx);
-  __ j(not_equal, &loop);
-
-  __ bind(&done);
-
-  // Set the bit in the map to indicate that there is no local valueOf field.
-  __ orp(FieldOperand(rbx, Map::kBitField2Offset),
-         Immediate(1 << Map::kStringWrapperSafeForDefaultValueOf));
-
-  __ bind(&skip_lookup);
-
-  // If a valueOf property is not found on the object check that its
-  // prototype is the un-modified String prototype. If not result is false.
-  __ movp(rcx, FieldOperand(rbx, Map::kPrototypeOffset));
-  __ testp(rcx, Immediate(kSmiTagMask));
-  __ j(zero, if_false);
-  __ movp(rcx, FieldOperand(rcx, HeapObject::kMapOffset));
-  __ movp(rdx, Operand(rsi, Context::SlotOffset(Context::GLOBAL_OBJECT_INDEX)));
-  __ movp(rdx, FieldOperand(rdx, GlobalObject::kNativeContextOffset));
-  __ cmpp(rcx,
-          ContextOperand(rdx, Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Split(equal, if_true, if_false, fall_through);
-
-  context()->Plug(if_true, if_false);
-}
-
-
 void FullCodeGenerator::EmitIsFunction(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);