RFR (XS) 8204961: JVMTI jtreg tests build warnings on 32-bit platforms

[David Holmes]

Hi Boris,

I added serviceability-dev as JVM TI and its tests are technically 
serviceability concerns.

On 14/06/2018 10:39 PM, Boris Ulasevich wrote:
> Hi all,
> 
> Please review the following patch:
>    https://bugs.openjdk.java.net/browse/JDK-8204961
>    http://cr.openjdk.java.net/~bulasevich/8204961/webrev.01
> 
> Recently opensourced JVMTI tests gives build warnings for ARM32 build. 

I'm guessing the compiler version must have changed since we last ran 
these tests on 32-bit ARM. :)

> GCC complains about conversion between 4-byte pointer to 8-byte jlong 
> type which is Ok in this case. I propose to hide warning using 
> conversion to intptr_t.

I was concerned about what the warnings might imply but now I see that a 
JVM TI "tag" is simply a jlong used to funnel real pointers around to 
use for the tagging. So on 32-bit the upper 32-bits of the tag will 
always be zero and there is no data loss in any of the conversions.

So assuming none of the other compilers complain about this, this seems 
fine to me.

Thanks,
David

> thanks,
> Boris