RFR: 8331731: ubsan: relocInfo.cpp:155:30: runtime error: applying non-zero offset 18446744073709551614 to null pointer

[Matthias Baesken]

When running on macOS with ubsan enabled, we see some issues in relocInfo  (hpp and cpp); those already occur in the build quite early.

/jdk/src/hotspot/share/code/relocInfo.cpp:155:30: runtime error: applying non-zero offset 18446744073709551614 to null pointer

Similar happens when we add to the _current pointer
    _current++;
this gives :
relocInfo.hpp:606:13: runtime error: applying non-zero offset to non-null pointer 0xfffffffffffffffe produced null pointer

Seems the pointer subtraction/addition worked so far, so it might be an option to disable ubsan for those 2 functions.

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Commit messages:
 - JDK-8331731

Changes: https://git.openjdk.org/jdk/pull/19424/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19424&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331731
  Stats: 6 lines in 2 files changed: 5 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/19424.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19424/head:pull/19424

PR: https://git.openjdk.org/jdk/pull/19424