On Tue, May 10, 2011 at 10:59 AM, Igor Stasenko <siguctua@gmail.com> wrote:
On 10 May 2011 09:48, Mariano Martinez Peck <marianopeck@gmail.com> wrote:
On Tue, May 10, 2011 at 9:41 AM, Marcus Denker <marcus.denker@inria.fr> wrote:
On May 10, 2011, at 9:32 AM, Mariano Martinez Peck wrote:
what is even worst, is that even after removing those correct CM, and doing a GC etc...they still don't disappear.
There is
ScriptLoader new cleanUpMethods
This is called from #cleanUpForRelease and normally should make sure
there
are no old methods.
hehehehe if I do: ScriptLoader new cleanUpForRelease, then inspect ((CompiledMethod allInstances select: [:each | each trailer kind = #VarLengthSourcePointer] ) )
they are not GC'ed and if then I click on the first element in the inspector.... VM CRASH!!! with both, InterpreterVM and CogVM.
:(
okay. it seems i found the offender. Its a CompiledMethod class>>cleanUp. It changing a source pointer of all non-installed methods to 0.
Good catch!!! :) Anyway, why CompiledMethod class >>cleanUp would like to destroy source pointers??? If I understood correctly (please correct me), all compiled methods will loose the pointer to sources and hence they will be decompiled after when they are ask their source! I must be wrong, because the dev image when it is build, it calls all cleanUp methods for classes, so CompiledMethod class >> cleanUp shuld have been called, but if I take the Pharo1.3 result, I can see the source code (not decompiled)
When i do this, my image hangs.
I have just tried and it crash!!! Actually, I evaluated CompiledMethod cleanUp. And just after cmd+b in CompiledMethod (to browse it) -> crash How it is possilbe it didn't crash while building the dev image? or the first time I browse a class? maybe this incorrect CM are created by the build process just after the cleanUp ?
Now i thinking that it should actually use empty trailer for those methods i.e. CompiledMethodTrailer empty..
Still i found it strange why some methods has broken bytecode.
Yes!! and why they are not GCed!!
My theory is that some nasty code somewhere copied a compiled methods using some unsafe technique, like:
1 to: oldMethod size do: [ :i | newMethod at: i put: (oldMethod at: i) ]
I will search to see if I find something. The thing is that it is reproducible. Each new dev image build from scratch in a core, has these guys.
Because when you constructing compiled method normally (by compiling them) , there is no way how you can get broken compiled methods. (we would discover it much much earlier,
yes, exactly.
and in fact CompiledMethodTrailers are working for more than a year in both pharo and squeak, and there was no any issues like this from their side).
+1
-- Best regards, Igor Stasenko AKA sig.
-- Mariano http://marianopeck.wordpress.com