[aarch64-port-dev ] hotspot jtreg runtime/BoolReturn/JNIBooleanTest.java failure

[Andrew Haley]

On 09/21/2018 12:02 PM, Andrey Petushkov wrote:

> Just wanted to ask whether you want this fixed in jdk11. Apparently
> now raw value of jboolean (i.e. u8) returned by JNI method fed into
> java code, where it’s treated in different way. (value != 0 vs bit0
> != 0) Not sure if it is considered to be belonging to BBB domain or
> just a mere possibility of application developers to shoot
> themselves into foot. I’d fix it with proper value conversion at
> http://hg.openjdk.java.net/jdk/jdk11/file/1ddf9a99e4ad/src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp#l1925
> <http://hg.openjdk.java.net/jdk/jdk11/file/1ddf9a99e4ad/src/hotspot/cpu/aarch64/sharedRuntime_aarch64.cpp#l1925>
> If you’d like I can prepare a patch (although I assume unless it’s
> BBB-type thing it’s probably too late for jdk11)

It's been a bug for a long time. I guess the best fix is to define
c2bool the same as x86 and use it in
TemplateInterpreterGenerator::generate_result_handler_for and
SharedRuntime::generate_native_wrapper.

Mind you, that behaviour is very odd: ignore all but the bottom 8 bits
of the result register and set the return value, i.e.:

  return (byte)result != 0 ? 1 : 0

I guess it makes sense, given that jbool is defined to be an unsigned
8-bit integer type.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
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