@Override
    public Object process(Node nd, Stack<Node> stack, NodeProcessorCtx procCtx,
                          Object... nodeOutputs) throws SemanticException {
      SMBJoinOpProcContext ctx = (SMBJoinOpProcContext) procCtx;
      ctx.JoinOpToTsOpMap.put((CommonMergeJoinOperator) nd,
              (TableScanOperator) stack.get(0));
      return null;
    }
TezCompiler translates the operator plan into TezTasks.
ql/src/java/org/apache/hadoop/hive/ql/parse/TezCompiler.java