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From "Mikhail Loenko" <mloe...@gmail.com>
Subject [DRLVM] contribution of alternative bytecode verifier
Date Wed, 14 Mar 2007 11:06:49 GMT
2007/3/14, Petrashkova, Vera Y <vera.y.petrashkova@intel.com>:
>
> Here are the results of VTS tests running:
> 4320 VTS tests were run
> 4183 - passed on DRLVM
> 4234 - passed on DRLVM with alternative bytecode verifier

Thanks, Vera!

So, some words about the contribution (H-3363)

As you probably know classic implementation of verifier requires
complex time and memory consuming dataflow analysis that generates a
proof of type safety.

Some alternative approaches, for example CLDC verifier, require the
class file to be annotated with the proof of type safety. To make sure
the byte code is valid, verifier just validates the proof. That
validation is fast and does not require much memory.

The contributed verifier is a new verification approach based on
Constraint Propagation. It takes the original Java Class File
containing no additional information. For that class file it neither
generates a direct proof of its validness nor validates any existing
proof.

Instead it generates a proof that a proof of validness does exist :)

The approach results in significant performance and memory footprint
advantage over regular verification.

I'm finishing a document describing new verification in more details
and going to put it into the Harmony docs

Thanks,
Mikhail

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