antlr C grammar to create AST

Is there any C grammar available which generates the AST, which includes all the parser rules using "^" and "!" notations?

I went through the book written by Terence Parr, to write such a grammar, but it seems that writing one such grammar for C lang is a time consuming process, so was wondering if its available already which can me save a lot of time!

(A grammar for a smaller subset of C language is also fine..)

Thanks :)