Progress towards shepherding debug info through SelectionDAG.

No functional effect yet.  This is still evolving and should
not be viewed as final.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98195 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/ScheduleDAG.h

@@ -227,6 +227,7 @@ namespace llvm {
   private:
     SDNode *Node;                       // Representative node.
     MachineInstr *Instr;                // Alternatively, a MachineInstr.
+    MachineInstr *DbgInstr;             // A dbg_value referencing this.
   public:
     SUnit *OrigNode;                    // If not this, the node from which
                                         // this node was cloned.
@@ -269,10 +270,10 @@ namespace llvm {
     /// SUnit - Construct an SUnit for pre-regalloc scheduling to represent
     /// an SDNode and any nodes flagged to it.
     SUnit(SDNode *node, unsigned nodenum)
-      : Node(node), Instr(0), OrigNode(0), NodeNum(nodenum), NodeQueueId(0),
-        Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0), NumSuccsLeft(0),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false),
+      : Node(node), Instr(0), DbgInstr(0), OrigNode(0), NodeNum(nodenum),
+        NodeQueueId(0),  Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
+        NumSuccsLeft(0), isTwoAddress(false), isCommutable(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false),
         isPending(false), isAvailable(false), isScheduled(false),
         isScheduleHigh(false), isCloned(false),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
@@ -281,10 +282,10 @@ namespace llvm {
     /// SUnit - Construct an SUnit for post-regalloc scheduling to represent
     /// a MachineInstr.
     SUnit(MachineInstr *instr, unsigned nodenum)
-      : Node(0), Instr(instr), OrigNode(0), NodeNum(nodenum), NodeQueueId(0),
-        Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0), NumSuccsLeft(0),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false),
+      : Node(0), Instr(instr), DbgInstr(0), OrigNode(0), NodeNum(nodenum),
+        NodeQueueId(0), Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
+        NumSuccsLeft(0), isTwoAddress(false), isCommutable(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false),
         isPending(false), isAvailable(false), isScheduled(false),
         isScheduleHigh(false), isCloned(false),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
@@ -292,10 +293,10 @@ namespace llvm {
 
     /// SUnit - Construct a placeholder SUnit.
     SUnit()
-      : Node(0), Instr(0), OrigNode(0), NodeNum(~0u), NodeQueueId(0),
-        Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0), NumSuccsLeft(0),
-        isTwoAddress(false), isCommutable(false), hasPhysRegDefs(false),
-        hasPhysRegClobbers(false),
+      : Node(0), Instr(0), DbgInstr(0), OrigNode(0), NodeNum(~0u),
+        NodeQueueId(0), Latency(0), NumPreds(0), NumSuccs(0), NumPredsLeft(0),
+        NumSuccsLeft(0), isTwoAddress(false), isCommutable(false),
+        hasPhysRegDefs(false), hasPhysRegClobbers(false),
         isPending(false), isAvailable(false), isScheduled(false),
         isScheduleHigh(false), isCloned(false),
         isDepthCurrent(false), isHeightCurrent(false), Depth(0), Height(0),
@@ -329,6 +330,20 @@ namespace llvm {
       return Instr;
     }
 
+    /// setDbgInstr - Assign the debug instruction for the SUnit.
+    /// This may be used during post-regalloc scheduling.
+    void setDbgInstr(MachineInstr *MI) {
+      assert(!Node && "Setting debug MachineInstr of SUnit with SDNode!");
+      DbgInstr = MI;
+    }
+
+    /// getDbgInstr - Return the debug MachineInstr for this SUnit.
+    /// This may be used during post-regalloc scheduling.
+    MachineInstr *getDbgInstr() const {
+      assert(!Node && "Reading debug MachineInstr of SUnit with SDNode!");
+      return DbgInstr;
+    }
+
     /// addPred - This adds the specified edge as a pred of the current node if
     /// not already.  It also adds the current node as a successor of the
     /// specified node.

include/llvm/CodeGen/SelectionDAG.h

@@ -35,6 +35,7 @@ class MachineConstantPoolValue;
 class MachineFunction;
 class MachineModuleInfo;
 class SDNodeOrdering;
+class SDDbgValue;
 class TargetLowering;
 
 template<> struct ilist_traits<SDNode> : public ilist_default_traits<SDNode> {
@@ -57,6 +58,46 @@ private:
   static void createNode(const SDNode &);
 };
 
+/// SDDbgInfo - Keeps track of dbg_value information through SDISel.  We do
+/// not build SDNodes for these so as not to perturb the generated code;
+/// instead the info is kept off to the side in this structure.  SDNodes may
+/// have an associated dbg_value entry in DbgValMap.  Debug info that is not
+/// associated with any SDNode is held in DbgConstMap.  It is possible for
+/// optimizations to change a variable to a constant, in which case the
+/// corresponding debug info is moved from the variable to the constant table
+/// (NYI).
+class SDDbgInfo {
+  DenseMap<const SDNode*, SDDbgValue*> DbgVblMap;
+  SmallVector<SDDbgValue*, 4> DbgConstMap;
+
+  void operator=(const SDDbgInfo&);   // Do not implement.
+  SDDbgInfo(const SDDbgInfo&);   // Do not implement.
+public:
+  SDDbgInfo() {}
+
+  void add(const SDNode *Node, SDDbgValue *V) {
+    DbgVblMap[Node] = V;
+  }
+  void add(SDDbgValue *V) { DbgConstMap.push_back(V); }
+  void remove(const SDNode *Node) {
+    DenseMap<const SDNode*, SDDbgValue*>::iterator Itr =
+                      DbgVblMap.find(Node);
+    if (Itr != DbgVblMap.end())
+      DbgVblMap.erase(Itr);
+  }
+  // No need to remove a constant.
+  void clear() {
+    DbgVblMap.clear();
+    DbgConstMap.clear();
+  }
+  SDDbgValue *getSDDbgValue(const SDNode *Node) {
+    return DbgVblMap[Node];
+  }
+  typedef SmallVector<SDDbgValue*, 4>::iterator ConstDbgIterator;
+  ConstDbgIterator DbgConstBegin() { return DbgConstMap.begin(); }
+  ConstDbgIterator DbgConstEnd() { return DbgConstMap.end(); }
+};
+
 enum CombineLevel {
   Unrestricted,   // Combine may create illegal operations and illegal types.
   NoIllegalTypes, // Combine may create illegal operations but no illegal types.
@@ -119,6 +160,9 @@ class SelectionDAG {
   /// the ordering of the original LLVM instructions.
   SDNodeOrdering *Ordering;
 
+  /// DbgInfo - Tracks dbg_value information through SDISel.
+  SDDbgInfo *DbgInfo;
+
   /// VerifyNode - Sanity check the given node.  Aborts if it is invalid.
   void VerifyNode(SDNode *N);
 
@@ -828,6 +872,20 @@ public:
   /// GetOrdering - Get the order for the SDNode.
   unsigned GetOrdering(const SDNode *SD) const;
 
+  /// AssignDbgInfo - Assign debug info to the SDNode.
+  void AssignDbgInfo(SDNode *SD, SDDbgValue *db);
+
+  /// RememberDbgInfo - Remember debug info with no associated SDNode.
+  void RememberDbgInfo(SDDbgValue *db);
+
+  /// GetDbgInfo - Get the debug info for the SDNode.
+  SDDbgValue *GetDbgInfo(const SDNode* SD);
+
+  SDDbgInfo::ConstDbgIterator DbgConstBegin() { 
+    return DbgInfo->DbgConstBegin(); 
+  }
+  SDDbgInfo::ConstDbgIterator DbgConstEnd() { return DbgInfo->DbgConstEnd(); }
+
   void dump() const;
 
   /// CreateStackTemporary - Create a stack temporary, suitable for holding the