220 40339 article Path: news.gmane.org!.POSTED!not-for-mail From: Daniel Gutson Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Runtime code generation and self modifying code Date: Fri, 5 Oct 2018 12:50:18 -0300 Lines: 196 Approved: news@gmane.org Message-ID: References: <4489f889-977c-45f2-8a2f-186ee3b06bff@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="0000000000001df48005777d3b1f" X-Trace: blaine.gmane.org 1538754512 19773 195.159.176.226 (5 Oct 2018 15:48:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 5 Oct 2018 15:48:32 +0000 (UTC) To: std-proposals Original-X-From: std-proposals+bncBDE3NBMV6UFBBR4Q33OQKGQE45VXIRY@isocpp.org Fri Oct 05 17:48:28 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-lf1-f71.google.com ([209.85.167.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1g8SL0-0004vv-7d for gclcip-std-proposals@m.gmane.org; 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[209.85.220.41]) by mx.google.com with SMTPS id 75-v6sor4943139ljs.2.2018.10.05.08.50.30 for (Google Transport Security); Fri, 05 Oct 2018 08:50:30 -0700 (PDT) Received-SPF: pass (google.com: domain of danielgutson@gmail.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; X-Received: by 2002:a2e:8ec6:: with SMTP id e6-v6mr6772377ljl.166.1538754629988; Fri, 05 Oct 2018 08:50:29 -0700 (PDT) In-Reply-To: X-Original-Sender: danielgutson@gmail.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=XJD0qscA; spf=pass (google.com: domain of danielgutson@gmail.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=danielgutson@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:40339 Archived-At: --0000000000001df48005777d3b1f Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable El vie., 5 de oct. de 2018 a la(s) 12:48, Rene Rivera (grafikrobot@gmail.co= m) escribi=C3=B3: > While I understand, and concur, with others statements regarding code > generation in the context of the the host program.. There are valid use > cases for dynamic code generation. For example targeting emulators and > GPUs. So perhaps you might want to rephrase your ideas in those terms. > former qemu developer here. It is a super specific case, which should be handled by a library in the best of cases. > > > On Thu, Oct 4, 2018 at 7:35 PM Matthew Fioravante > wrote: > >> One big area where dynamic languages are way ahead of C++ is runtime >> dynamic code generation or self modifying code. >> >> >> One tiny example is singleton initialization. The only safe way in C++ t= o >> do non-constexpr singletons is by lazy init. >> >> The problem with lazy init is that you have to pay for a branch on every >> access, and that usually involves an atomic check. >> >> What if you instead you atomically overwrote the check with NOPS. Then >> the branch is gone and accessing the object is as efficient as if it >> weren't lazy. >> >> Has anyone considered writing proposals for improving runtime code gen >> with C++? >> >> -- >> You received this message because you are subscribed to the Google Group= s >> "ISO C++ Standard - Future Proposals" group. >> To unsubscribe from this group and stop receiving emails from it, send a= n >> email to std-proposals+unsubscribe@isocpp.org. >> To post to this group, send email to std-proposals@isocpp.org. >> To view this discussion on the web visit >> https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/4489f889-97= 7c-45f2-8a2f-186ee3b06bff%40isocpp.org >> >> . >> > > > -- > -- Rene Rivera > -- Grafik - Don't Assume Anything > -- Robot Dreams - http://robot-dreams.net > > -- > You received this message because you are subscribed to the Google Groups > "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to std-proposals@isocpp.org. > To view this discussion on the web visit > https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAHEh_GiUrVM= %3Da7QK%2BiNuXqFwxXCLyMA7WiRfWmHo_qmceV9JSw%40mail.gmail.com > > . > --=20 Who=E2=80=99s got the sweetest disposition? One guess, that=E2=80=99s who? Who=E2=80=99d never, ever start an argument? Who never shows a bit of temperament? Who's never wrong but always right? Who'd never dream of starting a fight? Who get stuck with all the bad luck? --=20 You received this message because you are subscribed to the Google Groups "= ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/CAFdMc-1qjWOE-7xWG%2BX01x9hO0jy-97qoeP89z%2Bjf0%= 2BzuxxY-Q%40mail.gmail.com. --0000000000001df48005777d3b1f Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


El vie= .., 5 de oct. de 2018 a la(s) 12:48, Rene Rivera (grafikrobot@gmail.com) escribi=C3=B3:
While I understand, and concur, with= others statements regarding code generation in the context of the the host= program.. There are valid use cases for dynamic code generation. For examp= le targeting emulators and GPUs. So perhaps you might want to rephrase your= ideas in those terms.

former qemu de= veloper here.
It is a super specific case, which should be handle= d by a library in the best of cases.
=C2=A0


On Thu, Oct 4, 2018 at 7:35 PM Matthew Fioravante <fmatthew5876@gmail.com= > wrote:
One big area where dynamic languages are way ahead of C++ is runtime dyn= amic code generation or self modifying code.

<= br>
One tiny example is singleton initialization. The only safe w= ay in C++ to do non-constexpr singletons is by lazy init.
The problem with lazy init is that you have to pay for a branc= h on every access, and that usually involves an atomic check.
What if you instead you atomically overwrote the check with NOP= S. Then the branch is gone and accessing the object is as efficient as if i= t weren't lazy.

Has anyone considered writ= ing proposals for improving runtime code gen with C++?

--
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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit = https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/4489f889-977c-= 45f2-8a2f-186ee3b06bff%40isocpp.org.


--
-- Rene Rivera
-- Grafik = - Don't Assume Anything
-- Robot Dreams -=C2=A0http://robot-dreams.net

=

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposals+unsubscribe@isocpp.org.
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--
Who=E2=80=99s= got the sweetest disposition?
One guess, that=E2=80=99s who?
Who=E2= =80=99d never, ever start an argument?
Who never shows a bit of temperam= ent?
Who's never wrong but always right?
Who'd never dream of= starting a fight?
Who get stuck with all the bad luck?

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CAFdMc-1qjW= OE-7xWG%2BX01x9hO0jy-97qoeP89z%2Bjf0%2BzuxxY-Q%40mail.gmail.com.
--0000000000001df48005777d3b1f-- .