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To: dev@harmony.apache.org
From: Egor Pasko <egor.pasko@gmail.com>
Subject: Re: [doc] are KNOWN ISSUES and TODO items valid?
Date: 13 Dec 2006 16:38:59 +0600
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On the 0x23D day of Apache Harmony Mikhail Fursov wrote:
> Are there any samples to reproduce JIT problem? If not I can look through
> my archives..

I do not have any at the moment. Would be great. Need a sequence of
potentially exceptional instructions that fill in the maximum method
size. 

> On 12 Dec 2006 19:55:54 +0600, Egor Pasko <egor.pasko@gmail.com> wrote:
> >
> > On the 0x23C day of Apache Harmony Alexey Varlamov wrote:
> > > 11 Dec 2006 21:20:23 +0600, Egor Pasko <egor.pasko@gmail.com>:
> > > > On the 0x23A day of Apache Harmony Alexey Varlamov wrote:
> > > > > I've looked through "Known issues" page and dropped few items, which
> > > > > were resolved already:
> > > > > - Java assertions support
> > > > > - StackOverflowError support for JIT mode
> > > >
> > > > why?
> > > > we do not have SOE 100% safe yet, JIT algorithms can be caught with
> > > > SOE on large bytecodes. We should estimate how much stack we can take
> > > > before each graph traversal activity. Not done yet and leads to a
> > crash.
> > > >
> > > The difference is, a technical imperfection vs missing feature (which
> > > was originally listed) - so feel free to add a detailed TODO record
> > > instead.
> >
> > fine,
> >
> > I made a JIT task from that under the new chapter "JIT Stability":
> >
> > 4. Avoiding stack overflow in JIT C++ code
> >
> > Problem: If compiled method's size is large or in case of aggressive
> > inlining parameters are set in Jitrino.OPT the latter can crash with
> > stack overflow while recursively traversing the CFG (=Control Flow
> > Graph).
> >
> > Task: To avoid stack overflows, estimate the amount of space allocated
> > by each optimization stage, check that it does not exceed the
> > available free space on the stack. VM provides necessary functionality
> > to check that via VM helper function get_available_stack_size(). In
> > dangerous situations stop inlining or return JIT_FAILURE so that other
> > JITs (for example, Jitrino.JET) can pick the compilation task.
> >
> > http://wiki.apache.org/harmony/JIT_Development_Tasks
> >
> > if there is a JIRA issue for that, feel free to add a reference.
> >
> > --
> > Egor Pasko
> >
> >
> 
> 
> -- 
> Mikhail Fursov

-- 
Egor Pasko