From: Andrew Haley <aph@redhat.com>
To: Basile Starynkevitch <basile@starynkevitch.net>, jit@gcc.gnu.org
Cc: gcc@gcc.gnu.org
Subject: Re: GCC/JIT and precise garbage collection support?
Date: Thu, 01 Jan 2015 00:00:00 -0000 [thread overview]
Message-ID: <559F8519.6000107@redhat.com> (raw)
In-Reply-To: <559EF2F1.6000000@starynkevitch.net>
On 09/07/15 23:17, Basile Starynkevitch wrote:
> (this is triggered by a question on the Ocaml mailing list asking about
> SystemZ backend in Ocaml; SystemZ is today a backend for GCC & probably
> GCCJIT)
>
> We might want to support better good garbage collection schemes in GCC,
> particularily in GCCJIT. This is a
> thing that LLVM is known to be weak at, and we might aim to do much
> better. If we did, good frontends for
> good functional languages (e.g. F#, Ocaml, Haskell) might in the future
> profit of GCC technology. And even a Javascript engine based on GCCJIT
> could profit.
>
> A good GC is very probably a precise (sometimes generational copying) GC
> with write barriers
> (read the http://gchandbook.org/ for more, or at least the wikipage
> about garbage collection). So a good GC is changing pointers.
>
> So we need to know where, and provide a mechanism for, pointer values
> are located in the call stack (of the GCCJIT generated code), and
> probably provide some write barrier machinery.
It's going to be very hard. All our experience with GCJ shows that a
true precise GC in GCC is going to require major surgery in many
places. The HotSpot optimizing compilers are written with GC as a
basic requirement and it touches many places.
Andrew.
prev parent reply other threads:[~2015-07-10 8:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-01 0:00 Basile Starynkevitch
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Armin Rigo
2015-01-01 0:00 ` David Malcolm
2015-01-01 0:00 ` Armin Rigo
2015-01-01 0:00 ` Jeff Law
2015-01-01 0:00 ` Andrew Haley
2015-01-01 0:00 ` Trevor Saunders
2015-01-01 0:00 ` Andrew Haley [this message]
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