RFR: 8278479: RunThese test failure with +UseHeavyMonitors and +VerifyHeavyMonitors

[Dean Long]

On Thu, 30 Jun 2022 22:05:14 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This change adds a null check before calling into Runtime1::monitorenter when -XX:+UseHeavyMonitors is set. There's a null check in the C2 and interpreter code before calling the runtime function but not C1.
> 
> Tested with tier1-7 (a little of 8) and built on most non-oracle platforms as well.

Marked as reviewed by dlong (Reviewer).

src/hotspot/cpu/aarch64/c1_LIRAssembler_aarch64.cpp line 2563:

> 2561:     if (op->info() != NULL) {
> 2562:       int null_check_offset = __ offset();
> 2563:       __ null_check(obj, -1);

Suggestion:

      __ null_check(obj);

src/hotspot/cpu/arm/c1_LIRAssembler_arm.cpp line 2438:

> 2436:       int null_check_offset = __ offset();
> 2437:       __ null_check(obj);
> 2438:       add_debug_info_for_null_check(null_check_offset, op->info());

Is this equivalent to the following?

add_debug_info_for_null_check_here(op->info());
__ null_check(obj);

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PR: https://git.openjdk.org/jdk/pull/9339