Egor, You wrote, > The root cause is somewhere beyond the JIT. Have you agreed with Mikhail suggestion to fix http://issues.apache.org/jira/browse/HARMONY-1688 on JIT side?
With best regards, Alexei Fedotov, Intel Middleware Products Division >-----Original Message----- >From: Alexey Varlamov [mailto:[EMAIL PROTECTED] >Sent: Monday, October 09, 2006 4:16 PM >To: harmony-dev@incubator.apache.org >Subject: Re: [drlvm] Non-bug difference HARMONY-1688? > >2006/10/9, Alexey Varlamov <[EMAIL PROTECTED]>: >> 2006/10/9, Alexey Varlamov <[EMAIL PROTECTED]>: >> > 2006/10/9, Pavel Pervov <[EMAIL PROTECTED]>: >> > > Commenting on (1) I should note, that VM generally can't determine >the fact >> > > of "initiating" class loading; it can only be done in Java (except >bootstrap >> > > class loader, of course). >> > I presume you mean cases of direct calls to loadClass() from executed >> > Java code. Well, the same way VM loads array classes on its own, not >> > resorting to Java loader instance. So AFAIU, neither VM nor Java have >> > 100% chance to register initiating loading singly on their own. >> > >> Hey, I found the clear specification on (1)! Look at JVMS 2nd ed, Para >> 5.3.2 - 5.3.3, it reads: >> "First, the Java virtual machine determines whether L has already been >> recorded as an initiating loader of a class or interface denoted by N. >> If so, this class or interface is C, and no class creation is >> necessary. >> Otherwise the Java virtual machine invokes loadClass(N ) on L." > >[0] http://java.sun.com/docs/books/vmspec/2nd- >edition/html/ConstantPool.doc.html#79441 > >> So this is definitely bug of DRLVM, which should be fixed mainly on VM >> side. And we may want to think how to avoid data duplication in VM and >> kernel classes on this matter... >> >> > > AFAIK, there is the bug: DRLVM does not record initiating class >loader of a >> > > class. (1) is just the consequence. >> > Not really. After H-1363 (aka BBC), j.l.ClassLoader records initiated >> > classes. There may be some holes in impl (e.g. for array classes), but >> > kernel classes fulfill API contract in general. >> > >> > > >> > > >> > > On 10/9/06, Alexey Varlamov <[EMAIL PROTECTED]> wrote: >> > > > >> > > > Folks, >> > > > >> > > > Would you mind to spend some time looking at HARMONY-1688? Good >> > > > knowledge of classloading and security machinery is an advantage :) >> > > > >> > > > In short, we face 2 issues in DRLVM: >> > > > 1) DRLVM itself is not aware of classes initiated (in contrast to >> > > > defined ones) by a loader, and always delegates to Java classes for >> > > > lookup (except bootstrap loader, of course). This is not really >queer >> > > > behaviour, but seems incompartible with most VMs. BTW, currently >this >> > > > affects implementation of jvmtiGetClassLoaderClasses(), which I >> > > > believe has a bug - it returns defined classes only. >> > > > 2) j.s.AccessController of DRLVM treats system classes (i.e. loaded >by >> > > > bootstrap loader) equally with application classes while examining >> > > > execution stack, while RI seems to be simply skipping them. In >other >> > > > words, DRLVM would always perform >ProtectionDomain.checkPermission() >> > > > with AllPermission for bootstrap classes, and RI will omit such >check >> > > > if no user classes on stack. This potentially may produce subtle >> > > > effects in security-exigent areas. >> > > > >> > > > Also, both can be considered from performance perspective, probably >> > > > having somewhat negative impact. >> > > > What do you think, how will we resolve this? >> > > > >> > > > [0] http://issues.apache.org/jira/browse/HARMONY-1688 >> > > > >> > > > ------------------------------------------------------------------- >-- >> > > > Terms of use : http://incubator.apache.org/harmony/mailing.html >> > > > To unsubscribe, e-mail: harmony-dev- >[EMAIL PROTECTED] >> > > > For additional commands, e-mail: harmony-dev- >[EMAIL PROTECTED] >> > > > >> > > > >> > > >> > > >> > >> > >--------------------------------------------------------------------- >Terms of use : http://incubator.apache.org/harmony/mailing.html >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- Terms of use : http://incubator.apache.org/harmony/mailing.html To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
