Revert of [stubs] Port SubStringStub to TurboFan

src/code-stubs.h

 // 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.
 
 #ifndef V8_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/code-stub-assembler.h"
@@ skipping 3094 matching lines @@
 
  private:
   bool save_doubles() const { return SaveDoublesBits::decode(minor_key_); }
 
   class SaveDoublesBits : public BitField<bool, 0, 1> {};
 
   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
   DEFINE_PLATFORM_CODE_STUB(StoreBufferOverflow, PlatformCodeStub);
 };
 
-class SubStringStub : public TurboFanCodeStub {
+
+class SubStringStub : public PlatformCodeStub {
  public:
-  explicit SubStringStub(Isolate* isolate) : TurboFanCodeStub(isolate) {}
-
-  static compiler::Node* Generate(CodeStubAssembler* assembler,
-                                  compiler::Node* string, compiler::Node* from,
-                                  compiler::Node* to, compiler::Node* context);
-
-  void GenerateAssembly(CodeStubAssembler* assembler) const override {
-    assembler->Return(Generate(assembler,
-                               assembler->Parameter(Descriptor::kString),
-                               assembler->Parameter(Descriptor::kFrom),
-                               assembler->Parameter(Descriptor::kTo),
-                               assembler->Parameter(Descriptor::kContext)));
-  }
+  explicit SubStringStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(SubString);
-  DEFINE_CODE_STUB(SubString, TurboFanCodeStub);
+  DEFINE_PLATFORM_CODE_STUB(SubString, PlatformCodeStub);
 };
 
 class ToStringStub final : public PlatformCodeStub {
  public:
   explicit ToStringStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(TypeConversion);
   DEFINE_PLATFORM_CODE_STUB(ToString, PlatformCodeStub);
 };
 
@@ skipping 11 matching lines @@
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 
 extern Representation RepresentationFromMachineType(MachineType type);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_STUBS_H_