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From "Mikhail Fursov" <mike.fur...@gmail.com>
Subject Re: [drlvm][jitrino]Are there any static type checking and type propagation?
Date Wed, 04 Jul 2007 11:41:34 GMT

On 7/4/07, clara <clarazhang@gmail.com> wrote:
> Our objective is to exploit a more accurate inter-procedural k-layer EA,
> which
> will guide  the JIT-assisted GC (a bit like free-me [1]) or concurrency
> analysis.

Here my question is: do you want to  compute object lifetime and add free()
calls during compilation time only or  use special runtime variables to
track if method's  argument and return values of object type are escaped and
guard free() call with this variable check?

Our EA is dependant on SSA, and a rough inter-procedural k-layer EA has been
> implemented ( by writing a optpass ). We need type propagation  to obtain
> and
> analyze more related method. But we could not know how this kind of type
> propagation cost, and why jitrino implement inter-procedural analysis by
> inlining
> and not by cross-procedural infomation transfer.

The answer is: this is the easier way to get the same information. Using it
for a limited set of methods (hot methods) we do not need to invent new type
of profile and we do not depend on the fact if the method we want to analyze
was compiled before or not.
You can use cross-procedural profiles if it fits your needs better. I can
help you to integrate into EM's infrastructure and make it JIT independent.

Another problem is there are many objects referenced by many container
> objects
> in applications. Do you have some good advices on analyzing such objects?

Do you mean something like String and shared between different strings
char[] objects here or references from java.util.* containers?
Unfortunately I can't give any good advice here unless I learn details of
your method better.

Would it be OK if we start with simple examples and simple solutions and
advance step by step?

[1] Samuel Z. Guyer, Kathryn S. McKinley, and Daniel Frampton.
> Free-Me: a static analysis for automatic individual object.
> In PLDI 2006, Ottawa, Ontario, Canada reclamation, 2006.
> ----- Original Message -----
> From: "Mikhail Fursov" <mike.fursov@gmail.com>
> To: <dev@harmony.apache.org>
> Sent: Tuesday, July 03, 2007 5:43 PM
> Subject: Re: [drlvm][jitrino]Are there any static type checking and type
> propagation?
> > On 7/3/07, clara <clarazhang@gmail.com> wrote:
> >>
> >> Thanks.
> >>
> >> We are exploiting an inter-procedural k-layer escape analysis, which
> are
> >> not dependent on inlining. So we will do some cross-procedure type
> >> propagation ourselves. :-)
> >> Could you give us some advices on it according to your experiences?
> >>
> >>
> > First of all you can use JavaBytecodeTranslator to produce HIR for the
> > methods you are interested to analyze. Drop this HIR (do not inline it)
> > after you checked the data you need.
> >
> > Could you describe your task and proposed solution in more details, so
> we
> > can think about more precise advices?
> >
> > --
> > Mikhail Fursov
> >

Mikhail Fursov

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