From: Eliot Moss <moss@cs.umass.edu>
To: cygwin@cygwin.com, Brian Inglis <Brian.Inglis@SystematicSw.ab.ca>
Subject: Re: gcc and 128-bit compare/exchange
Date: Thu, 12 Mar 2020 18:49:04 -0400 [thread overview]
Message-ID: <4284f5b0-8328-6a7e-365e-1a8429bbc9ac@cs.umass.edu> (raw)
In-Reply-To: <ece91b2c-c5e8-9fe0-ee28-34ce655981a1@SystematicSw.ab.ca>
On 3/12/2020 5:13 PM, Brian Inglis wrote:
> On 2020-03-11 21:36, Eliot Moss wrote:
>> On 3/11/2020 12:30 PM, Brian Inglis wrote:
>>> On 2020-03-11 00:13, Eliot Moss wrote:
>>>> On 3/11/2020 1:31 AM, Brian Inglis wrote:
>>
>>> There are gcc bugzilla comments about requiring gcc to be built with glibc
>>> libatomic to guarantee indirect inline functions support, and presumably glibc
>>> detecting gcc indirect inline functions support, and not supporting other libc
>>> variants including musl, newlib, uclibc, etc.
>>>
>>> The problem is that newlib is BSD licensed and glibc is GPL and you can not
>>> contaminate newlib by looking at or including GPL code, although you may be able
>>> to do so in the Cygwin winsup library.
>>
>> Hmm. Well, I just install standard stuff on Linux and then on Cygwin, and
>> I see different behavior. I don't know how licenses come into that (I'm not
>> saying they don't, only that it exceeds my knowledge). Are you saying that
>> Cygwin's build of gcc is intended to work with other libraries in addition
>> to glibc, and hence Cygwin's gcc might have been built without some stuff
>> to avoid license contamination?
>
> All gccs allow building and working with any adequate libc including musl,
> newlib, uclibc, etc. but on Cygwin it is winsup for system stuff with newlib for
> generic stuff.
>
> All I was pointing out was that while you could not copy LGPLed glibc libatomic
> code to BSD licensed newlib, you should be able to copy LGPLed glibc libatomic
> code to LGPLed Cygwin winsup libc, if you want to enable it with ifuncs,
> assuming they work under Windows.
>
>> It is probably not worth my while to do my own build of gcc just for this.
>> I can just write my own wrapper for the __sync function. But it seemed
>> wrong / broken to me that the __atomic builtin did not do what was expected.
>>
>> (Brian, are you the maintainer, or is there someone else with whom the
>> conversation would be taken up?
>
> It's gcc maintainer (see announcement but post here), and base project
> committers for newlib (via newlib AT sourceware DOT org) and winsup (via cygwin
> DASH patches AT cygwin DOT com), ml archives in same place as Cygwin lists.
Thank you for the additional information. At this point, I remain a little
unclear as to what you are suggesting my next step should be:
- Are you suggesting I do my own private build?
- Are you suggesting that I email those other lists?
- Are you thinking that the relevant maintainer would be reading this and that,
for the moment, I should just wait for further response?
Regards - Eliot
next prev parent reply other threads:[~2020-03-12 22:49 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-09 2:29 Eliot Moss
2020-03-09 2:59 ` Eliot Moss
2020-03-10 20:35 ` Brian Inglis
2020-03-10 21:13 ` Eliot Moss
2020-03-11 5:31 ` Brian Inglis
2020-03-11 6:13 ` Eliot Moss
2020-03-11 16:30 ` Brian Inglis
2020-03-12 3:36 ` Eliot Moss
2020-03-12 21:13 ` Brian Inglis
2020-03-12 22:49 ` Eliot Moss [this message]
2020-03-13 5:35 ` Brian Inglis
2020-03-11 17:31 ` Achim Gratz
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