From: Jeff Law <law@redhat.com>
To: Aldy Hernandez <aldyh@redhat.com>,
Richard Biener <richard.guenther@gmail.com>
Cc: gcc-patches <gcc-patches@gcc.gnu.org>, Pedro Alves <palves@redhat.com>
Subject: Re: protected alloca class for malloc fallback
Date: Fri, 05 Aug 2016 16:23:00 -0000 [thread overview]
Message-ID: <082fc386-345c-efa1-e1cd-053b1aa989a3@redhat.com> (raw)
In-Reply-To: <57A4A4B9.9090908@redhat.com>
On 08/05/2016 08:37 AM, Aldy Hernandez wrote:
>
> After looking at all this code, I realize no size will fit all if we
> want something clean. So, I take my approach back. I think we're best
> served by a couple different approaches, depending on usage.
Yup.
>
> My question is, how wed are we to an alloca based approach? Can we
> replace the non-critical uses by std::string (diagnostics,
> BLAH_check_failed(), building a string to manipulate the output of
> env("SOME_VAR"), etc?).
I don't think we are at all wed to alloca.
>
> Then for things like the GCC driver wanting to create a vector of passed
> commands, we could use auto_vec<> (*gasp*, using a vector to represent a
> vector ;-)). Note that auto_vec<> uses malloc (or GC) but creating a
> malloc'd vector at startup is hardly on the fast path.
>
> For the remaining things we could use either alloca with a malloc
> fallback for trivial things like set_user_assembler_name() that only
> have one exit point, or take it on a case by case basis.
>
> But it seems to me that we can use an STL container for the non critical
> things (which are the majority of them), and something else (perhaps an
> RAII thinggie TBD later).
>
> Is this reasonable? I'd like to know before I spend any time converting
> anything to std::string and auto_vec<>.
Yes, this is all reasonable to me. I'm a big believer in moving towards
standard library implementations of things. In this case we get to
remove the allocas *and* make the code easier to grok for those that are
familiar with the C++ standard library.
Jeff
next prev parent reply other threads:[~2016-08-05 16:23 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-04 11:30 Aldy Hernandez
2016-08-04 12:58 ` Richard Biener
2016-08-04 15:19 ` Aldy Hernandez
2016-08-04 19:24 ` Jeff Law
2016-08-05 14:37 ` Aldy Hernandez
2016-08-05 15:15 ` Pedro Alves
2016-08-05 16:23 ` Jeff Law [this message]
2016-08-05 17:48 ` Richard Biener
2016-08-05 8:17 ` Richard Biener
2016-08-04 19:06 ` Pedro Alves
2016-08-04 19:16 ` Jeff Law
2016-08-04 19:22 ` Pedro Alves
2016-08-04 19:26 ` Jeff Law
2016-08-04 19:31 ` Pedro Alves
2016-08-05 2:10 ` Martin Sebor
2016-08-05 14:42 ` Aldy Hernandez
2016-08-05 17:56 ` Richard Biener
2016-08-05 18:16 ` Oleg Endo
2016-08-05 20:07 ` Richard Biener
2016-08-06 10:09 ` Aldy Hernandez
2016-08-06 10:15 ` Aldy Hernandez
2016-08-06 15:08 ` Richard Biener
2016-08-08 17:00 ` Jeff Law
2016-08-08 17:32 ` Trevor Saunders
2016-08-08 19:03 ` Richard Biener
2016-08-09 11:34 ` Oleg Endo
2016-08-09 17:34 ` Trevor Saunders
2016-08-10 17:03 ` Oleg Endo
2016-08-11 1:23 ` Trevor Saunders
2016-08-11 12:18 ` Oleg Endo
2016-08-11 17:55 ` Trevor Saunders
2016-08-20 2:29 ` Mike Stump
2016-08-21 20:00 ` C++11? (Re: protected alloca class for malloc fallback) Pedro Alves
2016-08-22 7:10 ` Trevor Saunders
2016-08-22 7:28 ` Richard Biener
2016-08-22 12:02 ` Eric Gallager
2016-08-22 12:58 ` Manuel López-Ibáñez
2016-08-22 22:08 ` Mike Stump
2016-08-23 23:17 ` Eric Gallager
2016-08-09 13:17 ` protected alloca class for malloc fallback Aldy Hernandez
2016-08-09 13:21 ` Bernd Schmidt
2016-08-10 10:04 ` Richard Biener
2016-08-10 10:12 ` Aldy Hernandez
2016-08-10 10:39 ` Richard Biener
2016-08-10 18:00 ` Jeff Law
2016-08-10 18:33 ` Richard Biener
2016-08-16 16:28 ` Jeff Law
2016-08-16 16:44 ` Jakub Jelinek
2016-08-16 16:47 ` Jeff Law
2016-08-16 17:54 ` Martin Sebor
2016-08-17 8:27 ` Richard Biener
2016-08-17 13:39 ` Martin Sebor
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