[stubs] Port SubStringStub to TurboFan

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 2af7f1567392d7058943a38fb81dec35226f3006..def93f4649c2a3c4e362e8bd1b8762276c012a24 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -426,6 +426,18 @@ class CodeStub BASE_EMBEDDED {
   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,                \
@@ -3121,13 +3133,12 @@ class StoreBufferOverflowStub : public PlatformCodeStub {
   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 {