clang-cc test.c -cfg-dump???

Hi,all

I wants to get the CFG of a source file (.c),it seems that clang-cc has
offered such a function,but when I enter in the following
command,nothing has happened:

clang-cc main.c -cfg-dump

Besides that ,when I want to output the AST,

clang-cc main.c -ast-dump>AST,

it outputs in the stdout,though I did a redirection to "AST" file.

What should I do if I want to get the CFG of a source code?

Thanks!

ZhuNan

clang-cc -analyze -cfg-dump main.c