Revert of Internalize strings in-place

src/s390/code-stubs-s390.cc

 // Copyright 2014 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.
 
 #if V8_TARGET_ARCH_S390
 
 #include "src/code-stubs.h"
 #include "src/api-arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
@@ skipping 1353 matching lines @@
   //     and go to (1). Otherwise bail out to runtime.
   // (4) Sequential string.  Load regexp code according to encoding.
   // (E) Carry on.
   /// [...]
 
   // Deferred code at the end of the stub:
   // (5) Long external string?  If not, go to (7).
   // (6) External string.  Make it, offset-wise, look like a sequential string.
   //     Go to (4).
   // (7) Short external string or not a string?  If yes, bail out to runtime.
-  // (8) Sliced or thin string.  Replace subject with parent.  Go to (1).
+  // (8) Sliced string.  Replace subject with parent.  Go to (1).
 
   Label seq_string /* 4 */, external_string /* 6 */, check_underlying /* 1 */,
       not_seq_nor_cons /* 5 */, not_long_external /* 7 */;
 
   __ bind(&check_underlying);
   __ LoadP(r2, FieldMemOperand(subject, HeapObject::kMapOffset));
   __ LoadlB(r2, FieldMemOperand(r2, Map::kInstanceTypeOffset));
 
   // (1) Sequential string?  If yes, go to (4).
 
   STATIC_ASSERT((kIsNotStringMask | kStringRepresentationMask |
                  kShortExternalStringMask) == 0x93);
   __ mov(r3, Operand(kIsNotStringMask | kStringRepresentationMask |
                      kShortExternalStringMask));
   __ AndP(r3, r2);
   STATIC_ASSERT((kStringTag | kSeqStringTag) == 0);
   __ beq(&seq_string, Label::kNear);  // Go to (4).
 
   // (2) Sequential or cons? If not, go to (5).
   STATIC_ASSERT(kConsStringTag < kExternalStringTag);
   STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
-  STATIC_ASSERT(kThinStringTag > kExternalStringTag);
   STATIC_ASSERT(kIsNotStringMask > kExternalStringTag);
   STATIC_ASSERT(kShortExternalStringTag > kExternalStringTag);
   STATIC_ASSERT(kExternalStringTag < 0xffffu);
   __ CmpP(r3, Operand(kExternalStringTag));
   __ bge(&not_seq_nor_cons);  // Go to (5).
 
   // (3) Cons string.  Check that it's flat.
   // Replace subject with first string and reload instance type.
   __ LoadP(r2, FieldMemOperand(subject, ConsString::kSecondOffset));
   __ CompareRoot(r2, Heap::kempty_stringRootIndex);
@@ skipping 267 matching lines @@
           Operand(SeqTwoByteString::kHeaderSize - kHeapObjectTag));
   __ b(&seq_string);  // Go to (4).
 
   // (7) Short external string or not a string?  If yes, bail out to runtime.
   __ bind(&not_long_external);
   STATIC_ASSERT(kNotStringTag != 0 && kShortExternalStringTag != 0);
   __ mov(r0, Operand(kIsNotStringMask | kShortExternalStringMask));
   __ AndP(r0, r3);
   __ bne(&runtime);
 
-  // (8) Sliced or thin string.  Replace subject with parent.  Go to (4).
-  Label thin_string;
-  __ CmpP(r3, Operand(kThinStringTag));
-  __ beq(&thin_string);
+  // (8) Sliced string.  Replace subject with parent.  Go to (4).
   // Load offset into ip and replace subject string with parent.
   __ LoadP(ip, FieldMemOperand(subject, SlicedString::kOffsetOffset));
   __ SmiUntag(ip);
   __ LoadP(subject, FieldMemOperand(subject, SlicedString::kParentOffset));
   __ b(&check_underlying);  // Go to (4).
-
-  __ bind(&thin_string);
-  __ LoadP(subject, FieldMemOperand(subject, ThinString::kActualOffset));
-  __ b(&check_underlying);  // Go to (4).
 #endif  // V8_INTERPRETED_REGEXP
 }
 
 static void CallStubInRecordCallTarget(MacroAssembler* masm, CodeStub* stub) {
   // r2 : number of arguments to the construct function
   // r3 : the function to call
   // r4 : feedback vector
   // r5 : slot in feedback vector (Smi)
   FrameScope scope(masm, StackFrame::INTERNAL);
 
@@ skipping 2652 matching lines @@
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref,
                            kStackUnwindSpace, NULL, return_value_operand, NULL);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_S390