Have the inst emitter add the !srcloc mdnode to the machine instr.
Have the asmprinter use the mdnode to scavenge a source location if
present.  Document this nonsense in langref.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100607 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index aa24e01..9495f82 100644
--- a/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -769,6 +769,12 @@
         break;
       }
     }
+    
+    // Get the mdnode from the asm if it exists and add it to the instruction.
+    SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode);
+    const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD();
+    MI->addOperand(MachineOperand::CreateMetadata(MD));
+    
     MBB->insert(InsertPos, MI);
     break;
   }