WIP: Implement ES6 Spread-calls

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index fb2fbe55df5398d9ed4d7c0351b5a888e9b8d0c3..1832c430068c9ae1916a44776368325ae95f46f9 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -827,6 +827,7 @@ class CallICStub: public PlatformCodeStub {
   }
 
   int arg_count() const { return state().arg_count(); }
+  bool is_spread() const { return state().is_spread(); }
 
   CallICState state() const {
     return CallICState(static_cast<ExtraICState>(minor_key_));
@@ -1652,10 +1653,12 @@ class RegExpConstructResultStub FINAL : public HydrogenCodeStub {
 
 class CallFunctionStub: public PlatformCodeStub {
  public:
-  CallFunctionStub(Isolate* isolate, int argc, CallFunctionFlags flags)
+  CallFunctionStub(Isolate* isolate, int argc, CallFunctionFlags flags,
+                   bool is_spread = false)
       : PlatformCodeStub(isolate) {
     DCHECK(argc >= 0 && argc <= Code::kMaxArguments);
-    minor_key_ = ArgcBits::encode(argc) | FlagBits::encode(flags);
+    minor_key_ = ArgcBits::encode(argc) | FlagBits::encode(flags) |
+                 IsSpreadBits::encode(is_spread);
   }
 
   static int ExtractArgcFromMinorKey(int minor_key) {
@@ -1670,14 +1673,19 @@ class CallFunctionStub: public PlatformCodeStub {
     return flags() == CALL_AS_METHOD || flags() == WRAP_AND_CALL;
   }
 
+  bool is_spread() const { return IsSpreadBits::decode(minor_key_); }
+
   bool NeedsChecks() const { return flags() != WRAP_AND_CALL; }
 
   void PrintName(std::ostream& os) const OVERRIDE;  // NOLINT
 
   // Minor key encoding in 32 bits with Bitfield <Type, shift, size>.
   class FlagBits : public BitField<CallFunctionFlags, 0, 2> {};
-  class ArgcBits : public BitField<unsigned, 2, Code::kArgumentsBits> {};
-  STATIC_ASSERT(Code::kArgumentsBits + 2 <= kStubMinorKeyBits);
+  class IsSpreadBits : public BitField<bool, FlagBits::kNext, 1> {};
+  class ArgcBits : public BitField<unsigned, IsSpreadBits::kNext,
+                                   Code::kArgumentsBits> {};
+
+  STATIC_ASSERT(Code::kArgumentsBits + 3 <= kStubMinorKeyBits);
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(CallFunction);
   DEFINE_PLATFORM_CODE_STUB(CallFunction, PlatformCodeStub);