Mikhail Fursov wrote:
On 10/19/06, Alex Astapchuk <[EMAIL PROTECTED]> wrote:
Pavel,
One more note.
> b) About call of java method during compilation time. Jit now make
class loading during compilation.
> It means that Jit make call of java method.
> So I don't think that it's the other case.
It is different.
The JIT itself does not call Java code.
All what JIT does is calling VM's resolve_{anything}. It's VM who may
execute the Java code during the resolution.
The JIT itself neither has a way to call an arbitrary Java method during
the compilation, neither has an access to JNI functionality.
Sounds reasonable. And this solution joins mine and Pavel's proposals: JIT
calls a VM method to resolve native address for direct call. JIT does not
I would also add that we can not use any Java-based resolution schemes
at all.
(Here I mean anything that implies execution of managed code during
compilation in order to resolve the things).
Doing so we would dig a huuuuge grave for ourselves: we'll get a number
of dead lock issues, as such a scheme will add a sporadic and random
locks inside a normal Java control flow. Exactly the same issue as we
had with mixing native and Java locks in the same control flow.
care how the address is resolved in VM.
Alex, Pavel, what do you think about this interface?
In order to think anything meaningful, it would be nice to see something
like a pseudo-code example. Something like a piece of Java code for the
helper.
Would you be so kind, please?
Let me presume several things - are you talking about anything like the
following?
//
// JIT side
//
ByteCodeTranslator::handleInvokeStatic() {
MethodDesc md = getMethodToInvoke();
ClassDesc klass = md.getClass();
if (klass.implements(NativeCallProvider) && /and what's here??/) {
// So, the VM is smart enough to find all the needed only by the name.
Right?
void* addr =
vm_get_special_native_method_address(md.get_fully_qualified_name())
insert_a_native_call(addr);
}
else {
proceed_as_usual_java_call();
}
}
The JIT side becomes simple, indeed.
What about the 'helper writer's' side?
What should be placed in the helper's Java code in order to make this
special call?
//
// Java side
//
package org.apache.hy.drvm.gc.helpers;
public class GCHelpers /*implements anything? */ {
/** it's fast path - will be inlined by JIT. */
private static Address fast_alloc(Address classHandle, int size) {
...
if (fast_path_succeeded) return allocated_address();
return perform_slow_path(classHandle, size);
}
/** it's slow path - implemented by gc.dll*/
// What's here? annotation? anything else?
private static Address perform_slow_path(Address classHandle, int size);
}
--
Thanks,
Alex
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