[aarch64-port-dev ] RFR: 8195685: AArch64: AArch64 cannot build with JDK-8174962

Andrew Dinn adinn at redhat.com
Mon Jan 22 10:24:08 UTC 2018

Hi Ningsheng,

On 22/01/18 07:16, Ningsheng Jian wrote:
> I can apply your patch cleanly to jdk10 except for some warnings about
> tabs found instead of spaces. I also launched a JTreg test for your
> patch, but one new failure found:
> test/hotspot/jtreg/gtest/GTestWrapper.java. Details updated in JBS.
> Could you please take a look?
Thanks for finding this problem. It relates to generation of a vtable
stub at the point where it creates code to lookup a vtable entry. The
code changes in the patch for 8195685 involve changes to code in a
different path which relates to generation of an itable stub and lookup
of a itable entry. So, I am not sure if this new error is a problem with
the fix or is an existing bug which has just manifested for other reasons.

Looking at the place where the error occurs it seems that the problem is
this call in MacroAssembler::lookup_virtual_method

  vtable_offset_in_bytes += vtable_index.as_constant() * wordSize;
  ldr(method_result, Address(recv_klass, vtable_offset_in_bytes));

It looks as if vtable_offset_in_bytes is out of range.

I will need to debug to see if this is what is going on. In the meantime
I'll hold off on pushing the patch to the jdk and jdk10 trees.


Andrew Dinn
Senior Principal Software Engineer
Red Hat UK Ltd
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