[jdk16] RFR: 8259560: Zero m68k: "static assertion failed: align" after JDK-8252049 [v2]

[Aleksey Shipilev]

> Debian folks report that Zero m68k (and seems only that arch) fails the static assert added by JDK-8252049. It affects at least JDK 16, but would affect more releases once JDK-8252049 is backported.
> 
> /<<PKGBUILDDIR>>/src/hotspot/share/oops/methodData.hpp: In constructor 'MethodData::CompilerCounters::CompilerCounters()':
> /<<PKGBUILDDIR>>/src/hotspot/share/oops/methodData.hpp:1987:55: error: static assertion failed: align
>  1987 | static_assert(sizeof(_trap_hist) % HeapWordSize == 0, "align");
>       |
> 
> I tried to massage the code so that `oops/methodData.hpp` is not touched when Zero is built (since Zero does not use compilers and related infra), but there are enough transitive dependencies to `oops/methodData.hpp` to make it quite messy. So instead I would just special-case it in place.

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Added another place where the build fails

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk16/pull/102/files
  - new: https://git.openjdk.java.net/jdk16/pull/102/files/5df0f200..6690bcb0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk16&pr=102&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk16&pr=102&range=00-01

  Stats: 5 lines in 1 file changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk16/pull/102.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk16 pull/102/head:pull/102

PR: https://git.openjdk.java.net/jdk16/pull/102