On 06/20, Luc Van Oostenryck wrote:
>
> On Tue, Jun 20, 2017 at 01:17:41PM +0200, Oleg Nesterov wrote:
> > On 06/19, Luc Van Oostenryck wrote:
> > >
> > > The motivation for this patch was to allow sparse to be
> > > compiled with clang which doesn't like what is done
> > > on VLAs in the MK_IDENT() macro.
> >
> > could you spell please? I don't understand why clang can't compile this
> > code and I am just curious.
>
> Sure, I should have added in the commit message. Here it is:
> test-dissect.c:50:16: warning: field 'ident' with variable sized type 'struct ident' not at the end of a struct or class is a GNU extension [-Wgnu-variable-sized-type-not-at-end]
> sym->ident = MK_IDENT("__asm__");
> ^
> ./dissect.h:31:16: note: expanded from macro 'MK_IDENT'
> struct ident ident; \
> ^
> test-dissect.c:50:25: error: initialization of flexible array member is not allowed
> sym->ident = MK_IDENT("__asm__");
> ^~~~~~~~~
> ./dissect.h:35:11: note: expanded from macro 'MK_IDENT'
> .name = s, \
> ^
Hmm. Now that I git-cloned the code I understand. And I can't recall why MK_IDENT() was
written this way, it simply doesn't look right. Probably can be fixed but I agree, lets
remove it.
> > > But also, I can't see any justification for not using the
> > > real thing to create identifiers: built_in_ident().
> >
> > Simply because MK_IDENT() is faster and simpler to use.
>
> I find this very weak. For the simplicity of use, in both cases
> there is just a single call with the same argument, for the speed,
> I really really doubt there is any measurable difference.
Yes, I didn't try to convince you this optimization actually makes sense,
just explained the motivation I (probably) had many years ago.
> > > dissect.h | 13 -------------
> > > test-dissect.c | 6 +++---
> >
> > iirc there should be another MK_IDENT user in dissect.c?
>
> No, it doesn't seem to, and the history tell that there it
> never had been the case, just the three in test-dissect.c
OK, my memory fooled me.
Thanks,
Oleg.
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