Add support for stack map generation in the X86 backend.

Originally implemented by Lang Hames.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193811 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 69c82d4..8ff8427 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -33,6 +33,7 @@
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/SelectionDAG.h"
+#include "llvm/CodeGen/StackMaps.h"
 #include "llvm/DebugInfo.h"
 #include "llvm/IR/CallingConv.h"
 #include "llvm/IR/Constants.h"
@@ -6879,6 +6880,8 @@
     SDValue OpVal = getValue(CI.getArgOperand(i));
     if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(OpVal)) {
       Ops.push_back(
+        DAG.getTargetConstant(StackMaps::ConstantOp, MVT::i64));
+      Ops.push_back(
         DAG.getTargetConstant(C->getSExtValue(), MVT::i64));
     } else
       Ops.push_back(OpVal);