[Sablevm-developer] Off topic (probably)

[Ian R. <ir...@cs...>]

Hi, hopefully this isn't too off topic and the work will help other
people.

> The initializer circular dependency sequence is described in details in
> the JVM spec.  So, you should simply implement the spec, and check
> that you are getting the expected result.  If not, then there's a bug;-)

The actual problem was when I inserted my system properties this lead to
File.<clinit> being ran which tried to use the properties I was
inserting. To stop this I stopped Math.<clinit> from being ran by
altering the definition of Hashtable.hash so it didn't need to use
Math.abs. I believe I follow the JVM spec for loading classes very
closely, although I haven't checked this rigorously.

My new problems are caused by the way my JVM works. I run class
initialisers as soon as a bytecode is executed that references the
uninitialised class. I have a restriction that the bytecode that
references this uninitialised class can't be executed by the static
initialiser we're about to run. Unfortunately this set of circumstances
happens in class/sablepath:

run FileInputStream.<clinit> calls:
run System.loadLibrary (java-io) --> wants Runtime.loadLibrary, Runtime
uninitialised therefore:
run Runtime.<clinit> calls:
run Runtime.<init> calls:
run File.<clinit> and oh no calls:
System.loadLibrary (java-io)

Obviously it should be legal in my JVM to execute System.loadLibrary in
this way as there are no restrictions placed on the code from the JVM
spec. However, it strikes me as wrong to be calling Runtime.loadLibrary
when Runtime hasn't been statically initialised. The numerous calls to
System.loadLibrary (java-io) seem excessive to me also (I can see why
they're made but is there no better way?). Anyhow, I have tried
pre-loading java/lang/Runtime and java/lang/System and both fail. You
can't pre-load java/lang/Runtime without java/lang/System setting up the
system properties. I can't pre-load java/lang/System as it leads to the
same error as the one listed above.

Any ideas before I remove my restriction? TIA. A simpler solution for me
would be to alter the behaviour of Runtime.<init> .

> I have updated the configure stuff, and merged with recent classpath
> changes.

Thanks for the reminder, I've subscribed to the mailing list and I
believe I'm up-to-date.

Cheers,

Ian Rogers