Rename ISD::LOCATION to ISD::DBG_STOPPOINT to better reflect its
purpose, and give it a custom SDNode subclass so that it doesn't
need to have line number, column number, filename string, and
directory string, all existing as individual SDNodes to be the
operands.

This was the only user of ISD::STRING, StringSDNode, etc., so
remove those and some associated code.

This makes stop-points considerably easier to read in
-view-legalize-dags output, and reduces overhead (creating new
nodes and copying std::strings into them) on code containing
debugging information.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52924 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6456fa3..c364e1f 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -382,6 +382,13 @@
   case ISD::Register:
     ID.AddInteger(cast<RegisterSDNode>(N)->getReg());
     break;
+  case ISD::DBG_STOPPOINT: {
+    const DbgStopPointSDNode *DSP = cast<DbgStopPointSDNode>(N);
+    ID.AddInteger(DSP->getLine());
+    ID.AddInteger(DSP->getColumn());
+    ID.AddPointer(DSP->getCompileUnit());
+    break;
+  }
   case ISD::SRCVALUE:
     ID.AddPointer(cast<SrcValueSDNode>(N)->getValue());
     break;
@@ -575,9 +582,6 @@
   bool Erased = false;
   switch (N->getOpcode()) {
   case ISD::HANDLENODE: return;  // noop.
-  case ISD::STRING:
-    Erased = StringNodes.erase(cast<StringSDNode>(N)->getValue());
-    break;
   case ISD::CONDCODE:
     assert(CondCodeNodes[cast<CondCodeSDNode>(N)->get()] &&
            "Cond code doesn't exist!");
@@ -738,15 +742,6 @@
                  getConstant(Imm, Op.getValueType()));
 }
 
-SDOperand SelectionDAG::getString(const std::string &Val) {
-  StringSDNode *&N = StringNodes[Val];
-  if (!N) {
-    N = new StringSDNode(Val);
-    AllNodes.push_back(N);
-  }
-  return SDOperand(N, 0);
-}
-
 SDOperand SelectionDAG::getConstant(uint64_t Val, MVT VT, bool isT) {
   MVT EltVT = VT.isVector() ? VT.getVectorElementType() : VT;
   return getConstant(APInt(EltVT.getSizeInBits(), Val), VT, isT);
@@ -1005,6 +1000,24 @@
   return SDOperand(N, 0);
 }
 
+SDOperand SelectionDAG::getDbgStopPoint(SDOperand Root,
+                                        unsigned Line, unsigned Col,
+                                        const CompileUnitDesc *CU) {
+  FoldingSetNodeID ID;
+  SDOperand Ops[] = { Root };
+  AddNodeIDNode(ID, ISD::DBG_STOPPOINT, getVTList(MVT::Other), &Ops[0], 1);
+  ID.AddInteger(Line);
+  ID.AddInteger(Col);
+  ID.AddPointer(CU);
+  void *IP = 0;
+  if (SDNode *E = CSEMap.FindNodeOrInsertPos(ID, IP))
+    return SDOperand(E, 0);
+  SDNode *N = new DbgStopPointSDNode(Root, Line, Col, CU);
+  CSEMap.InsertNode(N, IP);
+  AllNodes.push_back(N);
+  return SDOperand(N, 0);
+}
+
 SDOperand SelectionDAG::getSrcValue(const Value *V) {
   assert((!V || isa<PointerType>(V->getType())) &&
          "SrcValue is not a pointer?");
@@ -4178,7 +4191,6 @@
 void BinarySDNode::ANCHOR() {}
 void TernarySDNode::ANCHOR() {}
 void HandleSDNode::ANCHOR() {}
-void StringSDNode::ANCHOR() {}
 void ConstantSDNode::ANCHOR() {}
 void ConstantFPSDNode::ANCHOR() {}
 void GlobalAddressSDNode::ANCHOR() {}
@@ -4189,6 +4201,7 @@
 void SrcValueSDNode::ANCHOR() {}
 void MemOperandSDNode::ANCHOR() {}
 void RegisterSDNode::ANCHOR() {}
+void DbgStopPointSDNode::ANCHOR() {}
 void ExternalSymbolSDNode::ANCHOR() {}
 void CondCodeSDNode::ANCHOR() {}
 void ARG_FLAGSSDNode::ANCHOR() {}
@@ -4463,7 +4476,6 @@
   case ISD::AssertSext:    return "AssertSext";
   case ISD::AssertZext:    return "AssertZext";
 
-  case ISD::STRING:        return "String";
   case ISD::BasicBlock:    return "BasicBlock";
   case ISD::ARG_FLAGS:     return "ArgFlags";
   case ISD::VALUETYPE:     return "ValueType";
@@ -4624,7 +4636,7 @@
   case ISD::CTLZ:    return "ctlz";
 
   // Debug info
-  case ISD::LOCATION: return "location";
+  case ISD::DBG_STOPPOINT: return "dbg_stoppoint";
   case ISD::DEBUG_LOC: return "debug_loc";
 
   // Trampolines