From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Thomas Monjalon <thomas@monjalon.net>
Cc: "Mattias Rönnblom" <hofors@lysator.liu.se>, dev@dpdk.org
Subject: Re: [PATCH] eal: provide rte attribute macro for GCC attribute
Date: Tue, 20 Feb 2024 10:06:29 -0800 [thread overview]
Message-ID: <20240220180629.GB19214@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> (raw)
In-Reply-To: <3474620.eGJsNajkDb@thomas>
On Sun, Feb 18, 2024 at 04:31:50PM +0100, Thomas Monjalon wrote:
> 18/02/2024 15:51, Mattias Rönnblom:
> > On 2024-02-18 13:24, Thomas Monjalon wrote:
> > > 15/02/2024 23:20, Tyler Retzlaff:
> > >> Provide a new macro __rte_attribute(a) that when directly used
> > >> compiles to empty for MSVC and to __attribute__(a) when using GCC/LLVM.
> > >>
> > >> Replace direct use of __attribute__ in __rte_xxx macros where there is
> > >> existing empty expansion of the macro for MSVC allowing removal of
> > >> repeated #ifdef RTE_TOOLCHAIN_MSVC per macro to expand empty.
> > >
> > > I'm not sure it makes sense.
> > > I prefer seeing clearly what is empty with MSVC.
> >
> > Anything __rte_attribute() is empty on MSVC. You could rename it
> > __rte_attribute_ignored_by_msvc() for clarity.
>
> Yes it would bring more clarity.
> But I still prefer #ifdef which may work with more compilers.
>
> > One could note that on the ignore list are things like "may_alias" and
> > "packed", so whatever comes out of a MSVC build should not be expected
> > to actually work.
> >
> > Unless I'm missing something, for all the attributes that will have
> > MSVC-propriety equivalent, the usage pattern would have to change, since
> > the syntax is different in incompatible ways.
> >
> > Wouldn't it be better to ask the MSVC team to add support GCC
> > attributes? ICC and LLVM managed, so why not Microsoft. Then you would
> > solve this issue for all Open Source projects, not only DPDK.
>
> We can expect MSVC to improve.
> That's another reason why I prefer to keep #ifdef to keep track easily.
MSVC is committed to provide functionality where something simply cannot
be done at all with their toolset and standard C. They will not make
changes to their toolset for functionality they already have.
next prev parent reply other threads:[~2024-02-20 18:06 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-15 22:20 [PATCH] remove some MSVC conditional compile to empty Tyler Retzlaff
2024-02-15 22:20 ` [PATCH] eal: provide rte attribute macro for GCC attribute Tyler Retzlaff
2024-02-18 12:24 ` Thomas Monjalon
2024-02-18 12:53 ` Morten Brørup
2024-02-18 15:34 ` Thomas Monjalon
2024-02-18 16:38 ` Morten Brørup
2024-02-18 16:44 ` Thomas Monjalon
2024-02-20 17:50 ` Tyler Retzlaff
2024-02-18 14:51 ` Mattias Rönnblom
2024-02-18 15:31 ` Thomas Monjalon
2024-02-20 18:06 ` Tyler Retzlaff [this message]
2024-02-20 18:27 ` Thomas Monjalon
2024-02-27 22:45 ` [PATCH] remove some MSVC conditional compile to empty Tyler Retzlaff
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