Make context register implicit for CallInterfaceDescriptors

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 cfcae0bd94e597a677b202900790c367530e9a19..97d5d88413cb3daf700dd1e5d2d557e92fd703b2 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -98,15 +98,15 @@ void HydrogenCodeStub::GenerateLightweightMiss(MacroAssembler* masm,
   isolate()->counters()->code_stubs()->Increment();
 
   CallInterfaceDescriptor descriptor = GetCallInterfaceDescriptor();
-  int param_count = descriptor.GetEnvironmentParameterCount();
+  int param_count = descriptor.GetRegisterParameterCount();
   {
     // Call the runtime system in a fresh internal frame.
     FrameScope scope(masm, StackFrame::INTERNAL);
     DCHECK(param_count == 0 ||
-           rax.is(descriptor.GetEnvironmentParameterRegister(param_count - 1)));
+           rax.is(descriptor.GetRegisterParameter(param_count - 1)));
     // Push arguments
     for (int i = 0; i < param_count; ++i) {
-      __ Push(descriptor.GetEnvironmentParameterRegister(i));
+      __ Push(descriptor.GetRegisterParameter(i));
     }
     __ CallExternalReference(miss, param_count);
   }