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From "Simon Chow" <simon.harm...@gmail.com>
Subject Re: [drlvm][opt][translator] What dose JavaLabelPrepass do?
Date Thu, 17 Jan 2008 10:59:50 GMT
On 17 Jan 2008 13:31:05 +0300, Egor Pasko <egor.pasko@gmail.com> wrote:
>
> On the 0x3CE day of Apache Harmony Simon Chow wrote:
> > On 17 Jan 2008 11:08:54 +0300, Egor Pasko <egor.pasko@gmail.com> wrote:
> > >
> > > On the 0x3CD day of Apache Harmony Simon Chow wrote:
> > > > I am studying OPT in jitrino. For understanding the process of
> building
> > > CFG,
> > > > I have read some code of JavaByteCodeTranslator.
> > > > In the constructor of JavaByteCodeTranslator, there is an additional
> > > pass
> > > > named JavaLabelPrepass,
> > > > I would like to ask what is the exact purpose of this pass?
> > >
> > > the purpose is to mark basic blocks and inference stack variables and
> > > local variables with their types.
> > >
> > > This information goes to the input of JavaByteCodeTranslator, which in
> > > single pass goes through each bytecode instruction and converts it to
> > > operand-based representation from the stack-based in bytecode.
> > >
> > > The problem is a little tricky (with variable merging logic) and
> > > current design is poor.
> > >
> > > > Besides this, It is seems that the translator part will be refined,
> > > which I
> > > > saw in the wiki. Has it already been done in the current version?
> > > > Thanks!
> > >
> > > no, translator is not refined, low priority task.
> > >
> > > Why do you study the process of building CFG? If you want to do
> > > something with it, I would suggest to try some other place since all
> > > JIT people here will agree that debugging JavalabelPrepass is
> > > brain-damaging.
> >
> >
> > Thank!
> > I am doing a project for combining static compiler with dynamic
> compilation
> > environment (jitrino.OPT)
> > As first step, now I am planning to translate the Harmony IR to WHIRL.
>
> hm, do you have a kind of draft design document on how you want to do
> this? ..probably Harmony gurus can give some valuable input having
> read this doc.


There is no document for this yet, but I will write one in the next few days
after having a discussion with others in my group.
Our static compilation platform is Open64, some of my teammates are working
on it.
I only have a little understanding of jitrino.OPT.
For achieving higher performance, which part or phases of jitrino.OPT could
be refined or replaced by Open64 optimization?
Could you give me some suggestion?

By the way, This idea is original from Xiaofeng :)

Thank you every much!

> But I can not find more information for the CFG structure in jitrino.OPT,
> > which leads me to read the code in translation part. :(
> > Any advice for this?
>
> there is no complete reference guide for HIR instructions yet. Once I
> gave advice on this:
>
> http://article.gmane.org/gmane.comp.java.harmony.devel/24474/
>
> feel free to ask specific questions on CFG and instructions :)
>
> --
> Egor Pasko
>
>


-- 
>From : Simon.Chow@Software School of Fudan University

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