8186787: clang-4.0 SIGSEGV in Unsafe_PutByte

[zzambers]

This backport fixes failures (segfaults) in following tests which appeared after macos update:

sun/misc/CopyMemory.java 
compiler/unsafe/OpaqueAccesses.java

Backport differs from original changeset, because there were significant changes/refactoring in unsafe.

Notes:

• original changeset changes pointer returned by addr (MemoryAccess class), to volatile. Otherwise it is basically just refactoring.
• MemoryAccess is used by Unsafe_{Set,Put}* and Unsafe_{Set,Put}*Volatile functions, defined using DEFINE_GETSETOOP and DEFINE_GETSETOOP_VOLATILE macros
• jdk8 does not have MemoryAccess class, so equivalent pointers, in functions mentioned higher, are cast to volatile, to achieve same effect

Testing:
Tier1: OK (fixes sun/misc/CopyMemory.java and compiler/unsafe/OpaqueAccesses.java tests on macos, 1 failure on Linux x86 is timeout - seems unrelated, macos failures explained here: #544 (comment))

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• JDK-8186787 needs maintainer approval
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8186787: clang-4.0 SIGSEGV in Unsafe_PutByte (Bug - P2)

Reviewing

Using git

Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk8u-dev.git pull/553/head:pull/553
$ git checkout pull/553

Update a local copy of the PR:
$ git checkout pull/553
$ git pull https://git.openjdk.org/jdk8u-dev.git pull/553/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 553

View PR using the GUI difftool:
$ git pr show -t 553

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk8u-dev/pull/553.diff

Webrev

Link to Webrev Comment

[bridgekeeper]

👋 Welcome back zzambers! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

• 00: Full (4f40e7a9)

[zzambers]

Log from failing (segfaulting) tests (without fix, for reference):
CopyMemory-segfault.log
OpaqueAccesses-segfault.log

[bridgekeeper]

@zzambers This pull request has been inactive for more than 4 weeks and will be automatically closed if another 4 weeks passes without any activity. To avoid this, simply add a new comment to the pull request. Feel free to ask for assistance if you need help with progressing this pull request towards integration!

[zzambers]

keep open