RFR: JDK-8302043: [ AIX ] Safefetch fails for bad_addressN and bad_address32 [v2]

[Thomas Stuefe]

On Wed, 8 Feb 2023 12:36:46 GMT, Varada M <duke at openjdk.org> wrote:

>> On AIX, reading from lower range addresses like 5120(5K) does not cause a segmentation fault, though writing to them does. Hence the safefetch tests don't run as expected on AIX. This is solved by setting bad_addressN and bad_address32 to -1 for AIX. 
>> These tests under NMTGtests.java also passes :
>> gtest/NMTGtests.java#nmt-detail
>> gtest/NMTGtests.java#nmt-summary
>> gtest/NMTGtests.java#nmt-off
>> 
>> Reported issue: [JDK-8302043](https://bugs.openjdk.org/browse/JDK-8302043)
>
> Varada M has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Updated the segfault address for AIX
>  - Updated the segfault address for AIX

src/hotspot/share/utilities/vmError.hpp line 195:

> 193: #else
> 194:   static constexpr intptr_t segfault_address = (1*K);
> 195: #endif //AIX

Nit, could you please use 

static constexpr intptr_t segfault_address = AIX_ONLY(-1) NOT_AIX(1*K);

instead? Its a bit tighter coding.

Thanks!

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PR: https://git.openjdk.org/jdk/pull/12468