Access to source code from an analyser

[Alberto Lozano Alelu]

Hello.

I'm developing a C++ analyzer and I would like to get source text of
file when I'm analyzing C++ code.

When I'm analyzing source code I would like to get source text line
from a location of a type. I have got type location but I don't know a
function to get source line text from source location (file and line).
I'm looking in <gcc_root_dir>/libcpp.

Is there a function to get source text line from source location?

Thanks.