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From zouqiong <ust...@gmail.com>
Subject Re: [drlvm][opt] How to get object access sequence during runtime.
Date Wed, 24 Jan 2007 01:17:04 GMT
En, I don't know whether OPT can eliminate such code:
  aload_0
  getfield 5              aload_0
  aload_0           ==>    getfield 5
  getfield 5              dup

If it can eliminate them; I add tracing code as follows:

  aload_0                  aload_0
  getfield 5              call ObjectRecord
  aload_0           ==>    getfield 5
  getfield 5              aload_0
                          call ObjectRecord
                          getfield 5

I am afraid the instrumented "Call ObjectRecord" will cause the redundant
code can't be eliminated.


2007/1/23, Mikhail Fursov <mike.fursov@gmail.com>:
>
> On 1/23/07, zouqiong <ustczz@gmail.com> wrote:
> >
> > Hi, Mikhail:
> >    I implement code to trace object access just follow WB's way. But I'm
> > afraid that the instrumented code in ops like getfield would effect the
> > liveness analysis optimize?
>
>
> When we add new commands/types to optimizer we have to teach it how to
> deal
> with them. But I don't think that performance impact of a new 'use'
> operation for a field is critical. In your case the most performance
> impact
> will be due to the additional tracking call.
>
> Have I answered your question?
>
> --
> Mikhail Fursov
>
>


-- 
Best Regards,
Qiong,Zou

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