Revert of Internalize strings in-place

src/regexp/regexp-macro-assembler.cc

 // Copyright 2012 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/regexp/regexp-macro-assembler.h"
 
 #include "src/assembler.h"
 #include "src/isolate-inl.h"
 #include "src/regexp/regexp-stack.h"
 #include "src/simulator.h"
@@ skipping 115 matching lines @@
 }
 
 const byte* NativeRegExpMacroAssembler::StringCharacterPosition(
     String* subject,
     int start_index) {
   if (subject->IsConsString()) {
     subject = ConsString::cast(subject)->first();
   } else if (subject->IsSlicedString()) {
     start_index += SlicedString::cast(subject)->offset();
     subject = SlicedString::cast(subject)->parent();
-  } else if (subject->IsThinString()) {
-    subject = ThinString::cast(subject)->actual();
   }
   DCHECK(start_index >= 0);
   DCHECK(start_index <= subject->length());
   if (subject->IsSeqOneByteString()) {
     return reinterpret_cast<const byte*>(
         SeqOneByteString::cast(subject)->GetChars() + start_index);
   } else if (subject->IsSeqTwoByteString()) {
     return reinterpret_cast<const byte*>(
         SeqTwoByteString::cast(subject)->GetChars() + start_index);
   } else if (subject->IsExternalOneByteString()) {
@@ skipping 85 matching lines @@
 
   // The string has been flattened, so if it is a cons string it contains the
   // full string in the first part.
   if (StringShape(subject_ptr).IsCons()) {
     DCHECK_EQ(0, ConsString::cast(subject_ptr)->second()->length());
     subject_ptr = ConsString::cast(subject_ptr)->first();
   } else if (StringShape(subject_ptr).IsSliced()) {
     SlicedString* slice = SlicedString::cast(subject_ptr);
     subject_ptr = slice->parent();
     slice_offset = slice->offset();
-  } else if (StringShape(subject_ptr).IsThin()) {
-    subject_ptr = ThinString::cast(subject_ptr)->actual();
   }
   // Ensure that an underlying string has the same representation.
   bool is_one_byte = subject_ptr->IsOneByteRepresentation();
   DCHECK(subject_ptr->IsExternalString() || subject_ptr->IsSeqString());
   // String is now either Sequential or External
   int char_size_shift = is_one_byte ? 0 : 1;
 
   const byte* input_start =
       StringCharacterPosition(subject_ptr, start_offset + slice_offset);
   int byte_length = char_length << char_size_shift;
@@ skipping 96 matching lines @@
   }
   *stack_base = new_stack_base;
   intptr_t stack_content_size = old_stack_base - stack_pointer;
   return new_stack_base - stack_content_size;
 }
 
 #endif  // V8_INTERPRETED_REGEXP
 
 }  // namespace internal
 }  // namespace v8