Re: [build] Only support -gstabs on Mac OS X if assember supports it (PR target/67973)

[Rainer Orth <ro at CeBiTec dot Uni-Bielefeld dot DE>]

Hi Iain,

>> However, I'm not really comfortable with this solution.  Initially, I
>> forgot to wrap the -Q option to as in %{gstabs*:...}, which lead to a
>> bootstrap failure: the gas- and LLVM-based assemblers differ in a
>> number of other ways, as can be seen when comparing gcc/auto-host.h:
>
> FAOD, 
> the changes below only occur if you omit the guard on “-Q” ?
> or they are present always?

they are from previous builds, one with the LLVM-based /usr/bin/as, the
other configure with --with-as=/vol/gcc/bin/as-6.4 (gas-based as from
Xcode 6.4).

>> Given this, I'd rather have us not support stabs at all than via this
>> half-hearted approach.
>
> I agree, we should just disable it if the “default” assembler doesn’t
> support - so most of your patch would be unchanged.
> The actual practical outcome is really not terribly severe, it ony affects
> folks trying to target x86-darwin8 ( the last OS to use stabs as the first
> choice), and even those systems support some debugging with DWARF.
>> 
>> What do you think?
>
> My view is it should still be a configure test, rather than a blanket
> disable for d15+ (simply because I’ve got back-ports of the newer tools
> that should be useable across the Darwin range, and hopefully those
> back-ports will be published before Xmas).  The same issues would generally
> apply there.

Fine with me, it's certainly the safest approach.  I'll update the patch
accordingly.

	Rainer

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Rainer Orth, Center for Biotechnology, Bielefeld University