From: Xavier Leroy <Xavier.Leroy@inria.fr>
To: Joel Reymont <joelr1@gmail.com>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] Instruction selection in the OCaml compiler: Modules or classes?
Date: Thu, 22 Feb 2007 18:38:41 +0100 [thread overview]
Message-ID: <45DDD521.8080004@inria.fr> (raw)
In-Reply-To: <6CB0D237-F894-4AC3-BDBE-2BB484928D3C@gmail.com>
> I'm reading through the icfp99 slides on classes vs modules in OCaml.
> The part that I'm interested in starts on p27 where instruction
> selection in the OCaml compiler is discussed.
>
> I'm not well-versed in the OCaml compiler code yet so I thought I would
> ask the list: does the compiler use a module or class solution?
It uses classes, inheritance and overriding (of generic code by
processor-dependent code) for a few passes: instruction selection,
reloading of spilled registers, and instruction scheduling. The other
passes are either processor-independent or can be parameterized in a
simpler way (e.g. register allocation, which is parameterized by the
number of hardware registers in each register class).
> The slides seem to favor the class-based solution but then I hear that
> classes in OCaml are slow and people like Markus Mottl just plain
> despise them :-). What does everyone else opine?
Method dispatch is slightly slower than calls to unknown functions,
but the compiler passes that use objects are not speed-critical anyway
(most of the compilation time is spent elsewhere).
I don't despise objects and classes: it's just that the kind of code
that I usually write does not need them often. But there are some
cases where they work better than other forms of parameterization
available in OCaml. Ensuring that the native-code compiler is not
polluted all over the place by Intel x86-specific hacks is one of them.
- Xavier Leroy
next prev parent reply other threads:[~2007-02-22 17:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-22 14:38 Joel Reymont
2007-02-22 17:21 ` [Caml-list] " Tom
2007-02-22 17:38 ` Xavier Leroy [this message]
2007-02-22 19:55 ` Chris King
2007-02-22 19:59 ` Markus Mottl
2007-02-23 16:13 ` brogoff
2007-02-23 18:14 ` Tom
2007-02-23 19:28 ` [Caml-list] Instruction selection in the OCaml compiler: Modulesor classes? Andreas Rossberg
2007-02-24 2:51 ` skaller
2007-02-24 11:48 ` David Baelde
[not found] ` <4a708d20702240518l2c430b06r18fe64cabe5cbe9@mail.gmail.com>
2007-02-24 13:33 ` Lukasz Stafiniak
2007-02-24 14:58 ` [Caml-list] Instruction selection in the OCaml compiler:Modulesor classes? Andreas Rossberg
2007-02-24 17:39 ` skaller
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