Disable Clang Tool diagnostics

This will be a general question. I am currently writing a tool for clang which is related to AST traversal. So I have a frontendaction to create an ASTConsumer which, further, has a RecursiveASTVistor. I call Tool.run() to execute my action. It runs fine but clang by default prints out all the warnings and errors in the repo I try to analyze. Is there anyway I can disable clang diagnostics? I know that when we compile with clang, the -w option all disable diagnostics. But How do we do that for a tool? By the way, my tool resides in /llvm/tools/clang/tools/extra/mytool

Thanks.