Make all ExternalStrings bail out JIT code when accessing the sting contents

src/objects.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <iomanip>
 #include <sstream>
 
 #include "src/accessors.h"
@@ skipping 1163 matching lines @@
   bool is_one_byte = this->IsOneByteRepresentation();
   bool is_internalized = this->IsInternalizedString();
 
   // Morph the string to an external string by replacing the map and
   // reinitializing the fields.  This won't work if the space the existing
   // string occupies is too small for a regular  external string.
   // Instead, we resort to a short external string instead, omitting
   // the field caching the address of the backing store.  When we encounter
   // short external strings in generated code, we need to bailout to runtime.
   Map* new_map;
-  if (size < ExternalString::kSize) {
+  if (true) {
     new_map = is_internalized
         ? (is_one_byte
            ? heap->short_external_internalized_string_with_one_byte_data_map()
            : heap->short_external_internalized_string_map())
         : (is_one_byte ? heap->short_external_string_with_one_byte_data_map()
                        : heap->short_external_string_map());
   } else {
     new_map = is_internalized
         ? (is_one_byte
            ? heap->external_internalized_string_with_one_byte_data_map()
@@ skipping 45 matching lines @@
   Heap* heap = GetHeap();
   bool is_internalized = this->IsInternalizedString();
 
   // Morph the string to an external string by replacing the map and
   // reinitializing the fields.  This won't work if the space the existing
   // string occupies is too small for a regular  external string.
   // Instead, we resort to a short external string instead, omitting
   // the field caching the address of the backing store.  When we encounter
   // short external strings in generated code, we need to bailout to runtime.
   Map* new_map;
-  if (size < ExternalString::kSize) {
+  if (true) {
     new_map = is_internalized
                   ? heap->short_external_one_byte_internalized_string_map()
                   : heap->short_external_one_byte_string_map();
   } else {
     new_map = is_internalized
                   ? heap->external_one_byte_internalized_string_map()
                   : heap->external_one_byte_string_map();
   }
 
   // Byte size of the external String object.
@@ skipping 15102 matching lines @@
   if (cell->value() != *new_value) {
     cell->set_value(*new_value);
     Isolate* isolate = cell->GetIsolate();
     cell->dependent_code()->DeoptimizeDependentCodeGroup(
         isolate, DependentCode::kPropertyCellChangedGroup);
   }
 }
 
 }  // namespace internal
 }  // namespace v8