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

src/compiler/instruction-selector.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/compiler/instruction-selector.h"
 
 #include <limits>
 
 #include "src/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
@@ skipping 1064 matching lines @@
 void InstructionSelector::VisitGuard(Node* node) {
   OperandGenerator g(this);
   Node* value = node->InputAt(0);
   Emit(kArchNop, g.DefineSameAsFirst(node), g.Use(value));
 }
 
 
 void InstructionSelector::VisitParameter(Node* node) {
   OperandGenerator g(this);
   int index = ParameterIndexOf(node->op());
-  Emit(kArchNop,
-       g.DefineAsLocation(node, linkage()->GetParameterLocation(index),
-                          linkage()->GetParameterType(index)));
+  InstructionOperand op =
+      g.DefineAsLocation(node, linkage()->GetParameterLocation(index),
+                         linkage()->GetParameterType(index));
+
+  if (linkage()->ParameterHasSecondaryLocation(index)) {
+    InstructionOperand prespilled = g.DefineAsLocation(

[Jarin, 2015/11/12 12:08:33]

I am mildly surprised that it is possible to define the same node twice. Could
you add a comment here explaining why we do that?

[Mircea Trofin, 2015/11/12 18:01:35]

Will do - if we keep this design.

+        node, linkage()->GetParameterSecondaryLocation(index),
+        linkage()->GetParameterType(index));
+    InstructionOperand outputs[2] = {op, prespilled};
+    Emit(kArchNop, 2, outputs, 0, nullptr);
+  } else {
+    Emit(kArchNop, op);
+  }
 }
 
 
 void InstructionSelector::VisitIfException(Node* node) {
   OperandGenerator g(this);
   Node* call = node->InputAt(1);
   DCHECK_EQ(IrOpcode::kCall, call->opcode());
   const CallDescriptor* descriptor = OpParameter<const CallDescriptor*>(call);
   Emit(kArchNop, g.DefineAsLocation(node, descriptor->GetReturnLocation(0),
                                     descriptor->GetReturnType(0)));
@@ skipping 262 matching lines @@
   return new (instruction_zone()) FrameStateDescriptor(
       instruction_zone(), state_info.type(), state_info.bailout_id(),
       state_info.state_combine(), parameters, locals, stack,
       state_info.shared_info(), outer_state);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8