[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 408 matching lines @@
  public:                                                              \
   void InitializeDescriptor(CodeStubDescriptor* descriptor) override; \
   Handle<Code> GenerateCode() override;                               \
   DEFINE_CODE_STUB(NAME, SUPER)
 
 #define DEFINE_TURBOFAN_CODE_STUB(NAME, SUPER)                        \
  public:                                                              \
   void GenerateAssembly(CodeStubAssembler* assembler) const override; \
   DEFINE_CODE_STUB(NAME, SUPER)
 
+#define DEFINE_TURBOFAN_TERNARY_OP_CODE_STUB(NAME, SUPER)                      \
+ public:                                                                       \
+  static compiler::Node* Generate(                                             \
+      CodeStubAssembler* assembler, compiler::Node* first,                     \
+      compiler::Node* second, compiler::Node* third, compiler::Node* context); \
+  void GenerateAssembly(CodeStubAssembler* assembler) const override {         \
+    assembler->Return(                                                         \
+        Generate(assembler, assembler->Parameter(0), assembler->Parameter(1),  \
+                 assembler->Parameter(2), assembler->Parameter(3)));           \
+  }                                                                            \
+  DEFINE_CODE_STUB(NAME, SUPER)
+
 #define DEFINE_TURBOFAN_BINARY_OP_CODE_STUB(NAME, SUPER)                       \
  public:                                                                       \
   static compiler::Node* Generate(CodeStubAssembler* assembler,                \
                                   compiler::Node* left, compiler::Node* right, \
                                   compiler::Node* context);                    \
   void GenerateAssembly(CodeStubAssembler* assembler) const override {         \
     assembler->Return(Generate(assembler, assembler->Parameter(0),             \
                                assembler->Parameter(1),                        \
                                assembler->Parameter(2)));                      \
   }                                                                            \
@@ skipping 2675 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 PlatformCodeStub {
+class SubStringStub : public TurboFanCodeStub {
  public:
-  explicit SubStringStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
+  explicit SubStringStub(Isolate* isolate) : TurboFanCodeStub(isolate) {}
 
   DEFINE_ON_STACK_CALL_INTERFACE_DESCRIPTOR(3);
-  DEFINE_PLATFORM_CODE_STUB(SubString, PlatformCodeStub);
+  DEFINE_TURBOFAN_TERNARY_OP_CODE_STUB(SubString, TurboFanCodeStub);

[Igor Sheludko, 2016/09/22 12:23:37]

I don't think it's a ternary operation. It's just a stub that does a part of the
substring job. I think it would be cleaner if you expand this macro here and
give a parameters meaningful names. See FastNewClosureStub for example. 

And it would be better if you also use parameter indices defined in
SubStringDescriptor (see LoadICTrampolineTFStub::GenerateAssembly() for
example).

[jgruber, 2016/09/22 13:22:41]

Done.

 };
 
 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_