Possible bug in StackFrameInfo#getByteCodeIndex?
Martin Buchholz
martinrb at google.com
Tue Dec 12 19:08:15 UTC 2017
Out of curiosity, I looked more at StackFrameInfo, and saw:
short bci is final and is only ever assigned to -1 in java code. What's up
with that? Ohh, it seems to be magically frobbed in hotspot:
void java_lang_StackFrameInfo::set_bci(oop element, int value) {
element->int_field_put(_bci_offset, value);
}
BUT: bci should not be final if hotspot magic is frobbing it. Can we add a
comment explaining the magic? Also set_bci seems to disagree about the
type of bci - it's trying to set an int field, but bci is a short!
Also, I expected "int value" above to be "jint value" - it's a java type!
I would prefer bci to be a java int, not short, so that it can hold all
possible bytecode index values in a natural way, together with -1 for
"invalid". Right now, -1 is ambiguous - it might mean bci == 65535.
Also, I see
private final byte RETAIN_CLASS_REF = 0x01;
Shouldn't that be static?
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