RFR: 8278411: Implement UseHeavyMonitors consistently, s390 port

[Thomas Stuefe]

On Mon, 15 May 2023 08:25:19 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

> This PR make s390x to adapt the changes done in [JDK-8276901](https://bugs.openjdk.org/browse/JDK-8276901) OR implements UseHeavyMonitors. 
> 
> [JDK-8291555](https://bugs.openjdk.org/browse/JDK-8291555) still needs Porting effort. As for `LM_LIGHTWEIGHT` locking mode, code is Unimplemented.

src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp line 107:

> 105:     Unimplemented();
> 106:   } else if (LockingMode == LM_LEGACY) {
> 107:     NearLabel done;

I don't understand: should "consistent handling of UseHeavyMonitors" not lead to LM_MONITOR be handled here? E.g. by directly jumping into the slow case, without bothering with stack locking?

src/hotspot/cpu/s390/macroAssembler_s390.cpp line 3194:

> 3192:     // Set NE to indicate 'failure' -> take slow-path
> 3193:     z_ltgr(oop, oop);
> 3194:   }

Dont you need a break to done here?

src/hotspot/cpu/s390/macroAssembler_s390.cpp line 3270:

> 3268:     // Set NE to indicate 'failure' -> take slow-path
> 3269:     z_ltgr(oop, oop);
> 3270:   }

break to done?

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

PR Review Comment: https://git.openjdk.org/jdk/pull/13978#discussion_r1193707581
PR Review Comment: https://git.openjdk.org/jdk/pull/13978#discussion_r1193718060
PR Review Comment: https://git.openjdk.org/jdk/pull/13978#discussion_r1193720538