Track IR ordering of SelectionDAG nodes 1/4.

Use a field in the SelectionDAGNode object to track its IR ordering.
This adds fields and utility classes without changing existing
interfaces or functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182701 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 9188945..6d35694 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -80,8 +80,8 @@
 /// implementation that is parameterized by a TargetLowering object.
 ///
 class SelectionDAGBuilder {
-  /// CurDebugLoc - current file + line number.  Changes as we build the DAG.
-  DebugLoc CurDebugLoc;
+  /// CurInst - The current instruction being visited
+  const Instruction *CurInst;
 
   DenseMap<const Value*, SDValue> NodeMap;
   
@@ -327,7 +327,8 @@
 
   SelectionDAGBuilder(SelectionDAG &dag, FunctionLoweringInfo &funcinfo,
                       CodeGenOpt::Level ol)
-    : SDNodeOrder(0), TM(dag.getTarget()), TLI(dag.getTargetLoweringInfo()),
+    : CurInst(NULL), SDNodeOrder(0), TM(dag.getTarget()),
+      TLI(dag.getTargetLoweringInfo()),
       DAG(dag), FuncInfo(funcinfo), OptLevel(ol),
       HasTailCall(false) {
   }
@@ -364,7 +365,14 @@
   ///
   SDValue getControlRoot();
 
-  DebugLoc getCurDebugLoc() const { return CurDebugLoc; }
+  SDLoc getCurSDLoc() const {
+    assert(CurInst && "CurInst NULL");
+    return SDLoc(CurInst, SDNodeOrder);
+  }
+
+  DebugLoc getCurDebugLoc() const {
+    return CurInst ? CurInst->getDebugLoc() : DebugLoc();
+  }
 
   unsigned getSDNodeOrder() const { return SDNodeOrder; }