Factor out some platform-independent code into the shared cfg.cc.

src/x64/cfg-x64.cc

Index: src/x64/cfg-x64.cc
===================================================================
--- src/x64/cfg-x64.cc	(revision 2643)
+++ src/x64/cfg-x64.cc	(working copy)
@@ -103,7 +103,6 @@
 void ExitNode::Compile(MacroAssembler* masm) {
   ASSERT(!is_marked());
   is_marked_ = true;
-
   Comment cmnt(masm, "[ ExitNode");
   if (FLAG_trace) {
     __ push(rax);
@@ -123,19 +122,6 @@
 }
 
 
-void PositionInstr::Compile(MacroAssembler* masm) {
-  if (FLAG_debug_info && pos_ != RelocInfo::kNoPosition) {
-    __ RecordStatementPosition(pos_);
-    __ RecordPosition(pos_);
-  }
-}
-
-
-void MoveInstr::Compile(MacroAssembler* masm) {
-  location()->Move(masm, value());
-}
-
-
 void BinaryOpInstr::Compile(MacroAssembler* masm) {
   // The right-hand value should not be on the stack---if it is a
   // compiler-generated temporary it is in the accumulator.
@@ -211,6 +197,11 @@
 }
 
 
+void SlotLocation::Push(MacroAssembler* masm) {
+  __ push(ToOperand(this));
+}
+
+
 void SlotLocation::Move(MacroAssembler* masm, Value* value) {
   // We dispatch to the value because in some cases (temp or constant) we
   // can use special instruction sequences.
@@ -224,11 +215,6 @@
 }
 
 
-void SlotLocation::Push(MacroAssembler* masm) {
-  __ push(ToOperand(this));
-}
-
-
 void TempLocation::Get(MacroAssembler* masm, Register reg) {
   switch (where_) {
     case ACCUMULATOR: