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

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 7ebc1033db09f50a403d078f122cc508c2c2621b..c0c123d583a551c23a086f2d0cc4c0c8dee07aff 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -84,7 +84,7 @@ static void InitializeArrayConstructorDescriptor(Isolate* isolate,
   // stack param count needs (constructor pointer, and single argument)
   descriptor->stack_parameter_count_ = &rax;
   descriptor->register_params_ = registers;
-  descriptor->extra_expression_stack_count_ = 1;
+  descriptor->acting_as_js_function_ = true;
   descriptor->deoptimization_handler_ =
       FUNCTION_ADDR(ArrayConstructor_StubFailure);
 }
@@ -6814,8 +6814,8 @@ void StubFailureTrampolineStub::Generate(MacroAssembler* masm) {
   __ movq(rbx, MemOperand(rbp, parameter_count_offset));
   masm->LeaveFrame(StackFrame::STUB_FAILURE_TRAMPOLINE);
   __ pop(rcx);
-  __ lea(rsp, MemOperand(rsp, rbx, times_pointer_size,
-                         extra_expression_stack_count_ * kPointerSize));
+  int additional_offset = acting_as_js_function_ ? kPointerSize : 0;
+  __ lea(rsp, MemOperand(rsp, rbx, times_pointer_size, additional_offset));
   __ jmp(rcx);  // Return to IC Miss stub, continuation still on stack.
 }