[turbofan] Spill rsi and rdi in their existing locations.

src/compiler/linkage.cc

 // Copyright 2014 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/code-stubs.h"
 #include "src/compiler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node.h"
@@ skipping 548 matching lines @@
     // Local variable stored in this (callee) stack.
     int spill_index =
         index - first_stack_slot + StandardFrameConstants::kFixedSlotCount;
     return LinkageLocation::ForCalleeFrameSlot(spill_index);
   } else {
     // Parameter. Use the assigned location from the incoming call descriptor.
     int parameter_index = 1 + index;  // skip index 0, which is the target.
     return incoming_->GetInputLocation(parameter_index);
   }
 }
+
+
+bool Linkage::ParameterHasSecondaryLocation(int index) const {
+  if (incoming_->kind() != CallDescriptor::kCallJSFunction) return false;
+  LinkageLocation loc = GetParameterLocation(index);
+  return (loc == regloc(kJSFunctionRegister) ||
+          loc == regloc(kContextRegister));
+}
+
+LinkageLocation Linkage::GetParameterSecondaryLocation(int index) const {
+  DCHECK(ParameterHasSecondaryLocation(index));
+  LinkageLocation loc = GetParameterLocation(index);
+
+  if (loc == regloc(kJSFunctionRegister)) {
+    return LinkageLocation::ForCalleeFrameSlot(Frame::kJSFunctionSlot);
+  } else {
+    DCHECK(loc == regloc(kContextRegister));
+    return LinkageLocation::ForCalleeFrameSlot(Frame::kContextSlot);
+  }
+}
+
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8