RFR: Add a limition to allocate object heap in aarch64 with tsan enabled.

[Man Cao]

On Wed, 22 Apr 2020 03:02:59 GMT, Jie He <github.com+10233373+jhe33 at openjdk.org> wrote:

>> src/hotspot/share/runtime/arguments.cpp line 1864:
>> 
>>> 1863: #if defined(AARCH64)
>>> 1864: #define MAX_AVAILABLE_VM_SPACE_IN_AARCH64 (1024ULL * 1024ULL * 1024ULL * 16ULL) //16GB
>>> 1865: #define MSB_IN_AARCH64 (47) // Only support 48-bits space now.
>> 
>> The macros could be moved to tsan.hpp, and prefixed with "TSAN_", e.g. "TSAN_MSB_IN_AARCH64".
>> Or we could just use C++ const variable inline.
>> 
>> "__FUNCTION__" could also be used directly inline.
>
> I just see other functions have similar style, which define and use the Macros or const variables locally, due to
> merely one use place.

Those are likely from ancient code. Upstream OpenJDK is also moving away from that style.
See
https://wiki.openjdk.java.net/display/HotSpot/StyleGuide (search "Macros").

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PR: https://git.openjdk.java.net/tsan/pull/6