Deoptimizer support for hydrogen stubs that accept a variable number of arguments.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 1ee7c89d2a0da5d642efeff8873f2331412f10df..99ff5154e1e6c11c897f4765d18021723782ac2a 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -258,15 +258,17 @@ class PlatformCodeStub : public CodeStub {
 };
 
 
+enum StubFunctionMode { NOT_JS_FUNCTION_STUB_MODE, JS_FUNCTION_STUB_MODE };
+
 struct CodeStubInterfaceDescriptor {
   CodeStubInterfaceDescriptor()
       : register_param_count_(-1),
         stack_parameter_count_(NULL),
-        extra_expression_stack_count_(0),
+        function_mode_(NOT_JS_FUNCTION_STUB_MODE),
         register_params_(NULL) { }
   int register_param_count_;
   const Register* stack_parameter_count_;
-  int extra_expression_stack_count_;
+  StubFunctionMode function_mode_;
   Register* register_params_;
   Address deoptimization_handler_;
 
@@ -1601,10 +1603,8 @@ class StoreArrayLiteralElementStub : public PlatformCodeStub {
 
 class StubFailureTrampolineStub : public PlatformCodeStub {
  public:
-  static const int kMaxExtraExpressionStackCount = 1;
-
-  explicit StubFailureTrampolineStub(int extra_expression_stack_count)
-      : extra_expression_stack_count_(extra_expression_stack_count) {}
+  explicit StubFailureTrampolineStub(StubFunctionMode function_mode)
+      : function_mode_(function_mode) {}
 
   virtual bool IsPregenerated() { return true; }
 
@@ -1612,11 +1612,11 @@ class StubFailureTrampolineStub : public PlatformCodeStub {
 
  private:
   Major MajorKey() { return StubFailureTrampoline; }
-  int MinorKey() { return extra_expression_stack_count_; }
+  int MinorKey() { return static_cast<int>(function_mode_); }
 
   void Generate(MacroAssembler* masm);
 
-  int extra_expression_stack_count_;
+  StubFunctionMode function_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(StubFailureTrampolineStub);
 };