[builtins] Remove STRING_ADD_LEFT and STRING_ADD_RIGHT builtins.

src/full-codegen/arm64/full-codegen-arm64.cc

Index: src/full-codegen/arm64/full-codegen-arm64.cc
diff --git a/src/full-codegen/arm64/full-codegen-arm64.cc b/src/full-codegen/arm64/full-codegen-arm64.cc
index 9ad8e10b5fc8d852eaf1909554c93246fe3f62da..5363c026a72ac0fdb89a5f2b534c893a92c2359a 100644
--- a/src/full-codegen/arm64/full-codegen-arm64.cc
+++ b/src/full-codegen/arm64/full-codegen-arm64.cc
@@ -3031,108 +3031,6 @@ 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);
-
-  Register object = x0;
-  __ AssertNotSmi(object);
-
-  Register map = x10;
-  Register bitfield2 = x11;
-  __ Ldr(map, FieldMemOperand(object, HeapObject::kMapOffset));
-  __ Ldrb(bitfield2, FieldMemOperand(map, Map::kBitField2Offset));
-  __ Tbnz(bitfield2, Map::kStringWrapperSafeForDefaultValueOf, &skip_lookup);
-
-  // Check for fast case object. Generate false result for slow case object.
-  Register props = x12;
-  Register props_map = x12;
-  Register hash_table_map = x13;
-  __ Ldr(props, FieldMemOperand(object, JSObject::kPropertiesOffset));
-  __ Ldr(props_map, FieldMemOperand(props, HeapObject::kMapOffset));
-  __ LoadRoot(hash_table_map, Heap::kHashTableMapRootIndex);
-  __ Cmp(props_map, hash_table_map);
-  __ B(eq, if_false);
-
-  // Look for valueOf name 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 loop, done;
-
-  // Skip loop if no descriptors are valid.
-  Register descriptors = x12;
-  Register descriptors_length = x13;
-  __ NumberOfOwnDescriptors(descriptors_length, map);
-  __ Cbz(descriptors_length, &done);
-
-  __ LoadInstanceDescriptors(map, descriptors);
-
-  // Calculate the end of the descriptor array.
-  Register descriptors_end = x14;
-  __ Mov(x15, DescriptorArray::kDescriptorSize);
-  __ Mul(descriptors_length, descriptors_length, x15);
-  // Calculate location of the first key name.
-  __ Add(descriptors, descriptors,
-         DescriptorArray::kFirstOffset - kHeapObjectTag);
-  // Calculate the end of the descriptor array.
-  __ Add(descriptors_end, descriptors,
-         Operand(descriptors_length, LSL, kPointerSizeLog2));
-
-  // Loop through all the keys in the descriptor array. If one of these is the
-  // string "valueOf" the result is false.
-  Register valueof_string = x1;
-  int descriptor_size = DescriptorArray::kDescriptorSize * kPointerSize;
-  __ LoadRoot(valueof_string, Heap::kvalueOf_stringRootIndex);
-  __ Bind(&loop);
-  __ Ldr(x15, MemOperand(descriptors, descriptor_size, PostIndex));
-  __ Cmp(x15, valueof_string);
-  __ B(eq, if_false);
-  __ Cmp(descriptors, descriptors_end);
-  __ B(ne, &loop);
-
-  __ Bind(&done);
-
-  // Set the bit in the map to indicate that there is no local valueOf field.
-  __ Ldrb(x2, FieldMemOperand(map, Map::kBitField2Offset));
-  __ Orr(x2, x2, 1 << Map::kStringWrapperSafeForDefaultValueOf);
-  __ Strb(x2, FieldMemOperand(map, Map::kBitField2Offset));
-
-  __ Bind(&skip_lookup);
-
-  // If a valueOf property is not found on the object check that its prototype
-  // is the unmodified String prototype. If not result is false.
-  Register prototype = x1;
-  Register global_idx = x2;
-  Register native_context = x2;
-  Register string_proto = x3;
-  Register proto_map = x4;
-  __ Ldr(prototype, FieldMemOperand(map, Map::kPrototypeOffset));
-  __ JumpIfSmi(prototype, if_false);
-  __ Ldr(proto_map, FieldMemOperand(prototype, HeapObject::kMapOffset));
-  __ Ldr(global_idx, GlobalObjectMemOperand());
-  __ Ldr(native_context,
-         FieldMemOperand(global_idx, GlobalObject::kNativeContextOffset));
-  __ Ldr(string_proto,
-         ContextMemOperand(native_context,
-                           Context::STRING_FUNCTION_PROTOTYPE_MAP_INDEX));
-  __ Cmp(proto_map, string_proto);
-
-  PrepareForBailoutBeforeSplit(expr, true, if_true, if_false);
-  Split(eq, 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);