A custom command to dump a gimple/rtl function to file. By default, it
dumps the current function using 0 as dump_flags, but the function and flags
can also be specified. If /f <file> are passed as the first two arguments,
the dump is written to that file. Otherwise, a temporary file is created
and opened in the text editor specified in the EDITOR environment variable.
Examples of use:
(gdb) dump-fn
(gdb) dump-fn /f foo.1.txt
(gdb) dump-fn cfun->decl
(gdb) dump-fn /f foo.1.txt cfun->decl
(gdb) dump-fn cfun->decl 0
(gdb) dump-fn cfun->decl dump_flags