gcc --help for options which are not warnings or optimizations

gcc --help for options which are not warnings or optimizations

[Ian Lance Taylor]

Nick, how is gcc --help supposed to work for options which are neither
warnings nor optimizations?  For example, -fstack-protector.  Is there a
--help option which will display it?

Ian

Re: gcc --help for options which are not warnings or optimizations

[Nick Clifton]

Hi Ian,

> Nick, how is gcc --help supposed to work for options which are neither
> warnings nor optimizations?  For example, -fstack-protector.  Is there a
> --help option which will display it?

Yes - but only the generic "--help --verbose" rather than a more 
qualified version.

My original goal with the qualifiers for --help was to enable to 
automatic collection of all optimization options available in a 
particular version of gcc.  These would then be plugged in to a script 
to try out various different combinations of those options in the hopes 
of find the optimum selection.

I suppose we could add another qualifier along the lines of 
"--help=not-otherwise-shown" but that seems rather klunky.

Cheers
   Nick

Re: gcc --help for options which are not warnings or optimizations

[Diego Novillo]

On Tue, Jun 2, 2009 at 05:38, Nick Clifton <nickc@redhat.com> wrote:

> I suppose we could add another qualifier along the lines of
> "--help=not-otherwise-shown" but that seems rather klunky.

--help=other?

(I've got tons of other colors for this bike shed, if needed).


Diego.

Re: gcc --help for options which are not warnings or optimizations

[Ian Lance Taylor]

Nick Clifton <nickc@redhat.com> writes:

> Hi Ian,
>
>> Nick, how is gcc --help supposed to work for options which are neither
>> warnings nor optimizations?  For example, -fstack-protector.  Is there a
>> --help option which will display it?
>
> Yes - but only the generic "--help --verbose" rather than a more
> qualified version.

In that case I think that gcc --help should display something about
--verbose.

> I suppose we could add another qualifier along the lines of
> "--help=not-otherwise-shown" but that seems rather klunky.

Diego's --help=other suggestion seems reasonable.

Ian

Re: gcc --help for options which are not warnings or optimizations

[Nick Clifton]

Hi Ian, Hi Diego,

 > Diego Novillo wrote:
> --help=other?

That works. :-)

Actually, there already is a qualifier which will select 
-fstack-protector, I had just forgotten about it:

   % gcc --help=common | grep stack
   -Wstack-protector           Warn when not issuing stack smashing 
protection
   -fdefer-pop                 Defer popping functions args from stack until
   -fomit-frame-pointer        When possible do not generate stack frames
   -fstack-check               Insert stack checking code into the program
   -fstack-limit               This switch lacks documentation
   -fstack-limit-register=<register> Trap if the stack goes past <register>
   -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
   -fstack-protector           Use propolice as a stack protection method
   -fstack-protector-all       Use a stack protection method for every 
function

Cheers
   Nick