[jdk11u-dev] RFR: 8218136: minor hotspot adjustments for xlclang++ from xlc16 on AIX [v2]

[Tyler Steele]

> #993 
> 
> 8218136: minor hotspot adjustments for xlclang++ from xlc16 on AIX
> 
> Reviewed-by: dholmes, goetz, ihse
> 
> Backport Notes:
> 
> - src/hotspot/share/runtime/arguments.cpp: Remove `UNSUPPORTED_OPTION_NULL(AllocateOldGenAt)` modified by backport but not present in original source.

Tyler Steele has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Revert "8224214: [AIX] Remove support for legacy xlc compiler"
   
   This reverts commit 42a3518c41e197c60998643509159acf1072a924.
 - 8218136: minor hotspot adjustments for xlclang++ from xlc16 on AIX
   
   Reviewed-by: dholmes, goetz, ihse
   
   Backport Conflicts:
   - src/hotspot/share/runtime/arguments.cpp: Remove
   UNSUPPORTED_OPTION_NULL(AllocateOldGenAt).
   - src/hotspot/share/runtime/arguments.hpp: Add definition of
   UNSUPPORTED_OPTION_NULL.
   - src/hotspot/share/utilities/globalDefinitions_xlc.hpp: Header year
   clash.
 - 8224214: [AIX] Remove support for legacy xlc compiler
   
   Reviewed-by: erikj, kbarrett, mdoerr, dholmes
   
   Backport Conflicts:
   - make/autoconf/toolchain.m4: Update header year.
   - src/hotspot/share/gc/g1/ptrQueue.hpp: Remove procedure definition (cpp
   does not contian impl).
   - src/hotspot/share/gc/shared/oopStorage.hpp: Remove procedure
   definition (cpp does not contain impl).
   - src/hotspot/share/runtime/vm_version.cpp: Remove ~100 lines not
   present in base version.
   - src/hotspot/share/utilities/globalDefinitions_xlc.hpp: Add xlc version
   check.

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

Changes:
  - all: https://git.openjdk.java.net/jdk11u-dev/pull/997/files
  - new: https://git.openjdk.java.net/jdk11u-dev/pull/997/files/b9061fca..3782d6a0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=997&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk11u-dev&pr=997&range=00-01

  Stats: 12141 lines in 643 files changed: 6361 ins; 3580 del; 2200 mod
  Patch: https://git.openjdk.java.net/jdk11u-dev/pull/997.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk11u-dev pull/997/head:pull/997

PR: https://git.openjdk.java.net/jdk11u-dev/pull/997