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From "Ivan Popov" <ivan.g.po...@gmail.com>
Subject Re: Harmony+Eclipse and Scrapbook Pages
Date Mon, 23 Apr 2007 12:38:13 GMT
I've looked deeply at what happened in stepping over Scrapbook code,
and it seems that the problem is not in class loading due to JIT
algorithm, but because some JVMTI step events are not reported in JIT
mode.

Scrapbook code attempts to load class in an infinite loop using URL
classloader. This classloader issues NoClassDefFoundError internally
while attempting to load class from several URLs, but it is never
exposed to the user code.

The problem arises when this code is executed under debugger. After
application is stopped at breakpoint and debugger performs STEP OUT,
requested JVMTI step events are not reported until application goes to
a point where NoClassDefFoundError is thrown inside URLClassLoader
code and only here STEP event is generated and reported to Eclipse
debugger. It looks like Eclipse ignores such STEP event in unexpected
code and Scrapbook functionality fails.

In -Xint mode JVMTI STEP events are not skipped and Harmony reports
STEP event at expected place and this works well with Eclipse.

I'm going to file JIRA and provide simple test case to reproduce this problem.

Thanks.
Ivan


On 4/23/07, Tim Ellison <t.p.ellison@gmail.com> wrote:
> Mikhail Fursov wrote:
> > It proves that we have a bug here that can be fixed without lazy
> > resolution fixes. The only problem is to minimize the testcase.
>
> Let me know if I can be of any further help -- but it sounds like we
> need someone who understands the JITed stack walker, or other likely
> candidates for this bug.
>
> Running the snippet code in a simple test case passes ok for me, but it
> may not have been jitted.  What is the command-line option to force full
> optimized jitting eagerly?
>
> Regards,
> Tim
>

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