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Re: [RFH] Uses of output.h in the front ends
On Mon, Jun 4, 2012 at 10:04 PM, David Edelsohn <dje.gcc@gmail.com> wrote:
> On Mon, Jun 4, 2012 at 3:53 PM, Steven Bosscher <stevenb.gcc@gmail.com> wrote:
>
>> What I don't understand, is whether this is still something GNAT has
>> to support, or whether this code can be deprecated/removed. And I ask
>> for your help because you are one of the people who worked on this
>> so-many-years ago
>> (http://gcc.gnu.org/ml/gcc-patches/2004-12/msg00550.html) and because
>> you obviously have much better understanding of GNAT and of how this
>> kind of low-level thing works in GCC than I do.
>>
>> If this should continue to be supported:
>> For the corresponding option for G++ (-fconserve-space) the
>> documentation says that the flag isn't very useful anymore because:
>> "This option is no longer useful on most targets, now that support has
>> been added for putting variables into BSS without making them common."
>> What I don't understand, is what this means for GNAT. (Remember, I
>> help build aircraft for a living, not compilers! I can barely
>> distinguish .bss from .data, and don't understand at all where/how GCC
>> decides to put variables in one section or another :-D) I was hoping
>> maybe you know how to rewrite that piece of code such that you get
>> that uninitialized variable into BSS without DECL_COMMON.
>>
>> Or maybe you can tell if this code is no longer needed, so I can
>> prepare a patch to remove it.
>
> Is this feature necessary for non-ELF file formats, such as AIX XCOFF?
Maybe. But none of the other front ends seem to need this to put
uninitialized variables in a.bss-like section.
Ciao!
Steven