Compiler options as string?

[Tobias Burnus <burnus at net-b dot de>]

 I wonder what is the best way to obtain the compiler options as string 
in a front end.

Background: Fortran 2008 offers an intrinsic function called 
"compiler_options", which returns "a processor-dependent value which 
describes the options that controlled the translation phase of program 
execution." (Cf. PR 40569)

So far I found -frecord-gcc-switches, -fverbose-asm (cf. toplev.c's 
print_switch_values and init_asm_output).

The bare strings are only available in toplev.c: toplev_main directly 
gets (argc, argv), calls decode_options and saves them in static 
variable save_decoded_options, which is used for print_switch_values.

Thus, one needs to modify toplev to make them somehow available. Any 
suggestions how this should be done?

Tobias

PS: Some options such as FE specific options end up in gfc_handle_option 
(alias lang_hooks.handle_option) but those to not contain options such 
as "-march=native", "-O3" or "-m32" which users presumably would like to 
see recorded. -- I think most users would prefer to have the options to 
the driver ("gfortran") rather than the one to the compiler ("f951").