[runtime] Optimize and unify rest parameters.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index afd6770db879c89f1f5bfde3d8b4c4a6bf083602..21f1d03c8cf7b3a5e4d0cdce660781d08f230547 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -44,7 +44,6 @@ namespace internal {
   V(MathPow)                                \
   V(ProfileEntryHook)                       \
   V(RecordWrite)                            \
-  V(RestParamAccess)                        \
   V(RegExpExec)                             \
   V(StoreBufferOverflow)                    \
   V(StoreElement)                           \
@@ -78,6 +77,7 @@ namespace internal {
   V(FastCloneShallowObject)                 \
   V(FastNewClosure)                         \
   V(FastNewContext)                         \
+  V(FastNewRestParameter)                   \
   V(GrowArrayElements)                      \
   V(InternalArrayNArgumentsConstructor)     \
   V(InternalArrayNoArgumentConstructor)     \
@@ -725,6 +725,20 @@ class FastNewContextStub final : public HydrogenCodeStub {
 };
 
 
+// TODO(turbofan): This stub should be possible to write in TurboFan
+// using the CodeStubAssembler very soon in a way that is as efficient
+// and easy as the current handwritten version, which is partly a copy
+// of the strict arguments object materialization code.
+class FastNewRestParameterStub final : public PlatformCodeStub {
+ public:
+  explicit FastNewRestParameterStub(Isolate* isolate)
+      : PlatformCodeStub(isolate) {}
+
+  DEFINE_CALL_INTERFACE_DESCRIPTOR(FastNewRestParameter);
+  DEFINE_PLATFORM_CODE_STUB(FastNewRestParameter, PlatformCodeStub);
+};
+
+
 class FastCloneRegExpStub final : public HydrogenCodeStub {
  public:
   explicit FastCloneRegExpStub(Isolate* isolate) : HydrogenCodeStub(isolate) {}
@@ -1854,20 +1868,6 @@ class ArgumentsAccessStub: public PlatformCodeStub {
 };
 
 
-class RestParamAccessStub : public PlatformCodeStub {
- public:
-  explicit RestParamAccessStub(Isolate* isolate) : PlatformCodeStub(isolate) {}
-
- private:
-  void GenerateNew(MacroAssembler* masm);
-
-  void PrintName(std::ostream& os) const override;  // NOLINT
-
-  DEFINE_CALL_INTERFACE_DESCRIPTOR(RestParamAccess);
-  DEFINE_PLATFORM_CODE_STUB(RestParamAccess, PlatformCodeStub);
-};
-
-
 class RegExpExecStub: public PlatformCodeStub {
  public:
   explicit RegExpExecStub(Isolate* isolate) : PlatformCodeStub(isolate) { }