[turbofan] Introduce JSCallForwardVarargs operator.

src/interface-descriptors.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
 
 
@@ skipping 415 matching lines @@
 
 void CallTrampolineDescriptor::InitializePlatformIndependent(
     CallInterfaceDescriptorData* data) {
   // kFunction, kActualArgumentsCount
   MachineType machine_types[] = {MachineType::AnyTagged(),
                                  MachineType::Int32()};
   data->InitializePlatformIndependent(arraysize(machine_types), 0,
                                       machine_types);
 }
 
+void CallForwardVarargsDescriptor::InitializePlatformIndependent(
+    CallInterfaceDescriptorData* data) {
+  // kTarget, kStartIndex
+  MachineType machine_types[] = {MachineType::AnyTagged(),
+                                 MachineType::Int32()};
+  data->InitializePlatformIndependent(arraysize(machine_types), 0,
+                                      machine_types);
+}
+
 void ConstructStubDescriptor::InitializePlatformIndependent(
     CallInterfaceDescriptorData* data) {
   // kFunction, kNewTarget, kActualArgumentsCount, kAllocationSite
   MachineType machine_types[] = {MachineType::AnyTagged(),
                                  MachineType::AnyTagged(), MachineType::Int32(),
                                  MachineType::AnyTagged()};
   data->InitializePlatformIndependent(arraysize(machine_types), 0,
                                       machine_types);
 }
 
@@ skipping 147 matching lines @@
     CallInterfaceDescriptorData* data) {
   // kNumberOfArguments, kFirstArgument, kFunctionEntry
   MachineType machine_types[] = {MachineType::Int32(), MachineType::Pointer(),
                                  MachineType::Pointer()};
   data->InitializePlatformIndependent(arraysize(machine_types), 0,
                                       machine_types);
 }
 
 }  // namespace internal
 }  // namespace v8