FYI: Patch: Make Method.invoke() and JNI_CallAnyMethod use vtables

[Bryce McKinlay <bryce at mckinlay dot net dot nz>]

This patch improves Method.invoke() and JNI by having them dispatch via 
the vtable instead of doing runtime lookups via 
_Jv_LookupDeclaredMethod. This makes Method.invoke() about 25% faster 
for a simple virtual call test with no arguments, and probably a lot 
more than that in cases where the target class has a lot of methods or 
complex inheritance. It should also fix potential bugs, eg a virtual 
call to a package-private method that hides a similar declaration in 
its superclass. No "make check" regressions.

My tests show we're now only slightly slower than the JRE for a 
no-argument, public Method.invoke() call, but are 3-4X slower when 
arguments are involved. Incidentally, JNI calls seem to be at least 10X 
slower than the JRE (for java->native calls, which this patch doesn't 
effect). I imagine that speeding JNI up would help SWT and AWT 
significantly.

Regards

Bryce

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