Problem with target_flags_explicit and configure_default_options

[Steve Ellcey]

On Wed, 2012-06-06 at 23:19 +0200, Eric Botcazou wrote:
> > This is a followup mail to http://gcc.gnu.org/ml/gcc/2012-05/msg00400.html
> > now that I understand my problem better and can change the subject line to
> > reflect that.
> 
> I'm not sure whether digging into the behavior of the driver is the best way to 
> solve this kind of testsuite problems.  I think you should consider adding a
> new dg-require-effective-target marker instead.

You are probably right, I don't think I need a new
dg-require-effective-target marker though, for most (maybe all) of them
I can just specify that they use the -mno-synci flag.  The tests in
question are already mips specific tests that specify an older
architecture via some flag.

> > Does anyone have any ideas on telling the two cases apart?
> 
> I think that there is no simple solution.  We needed something like that a 
> while ago to implement the -s switch of the gnatmake command of the GNAT 
> compiler and we ended up with a scheme where gnatmake prepends and appends 
> special switches to the command line it is passed, sends the result to the 
> driver which also prepends and appends its own stuff before calling the real 
> compiler (gnat1 here), and we have parameterized the specs (lang-specs.h) so 
> that the driver doesn't modify the order of the special switches wrt the -m 
> switches.  As a result, gnat1 knows that any -m switch before the prepended 
> special switch or after the appended special switch comes from the driver.

Yuck.  I think that suppressing the warning is the right thing to do,
but I am not sure it is worth this much effort.  Changing the testsuite
is easier.

Steve Ellcey
sellcey@mips.com