RFR: 8304743: Compile_lock and SystemDictionary updates

[Vladimir Ivanov]

On Fri, 31 Mar 2023 13:23:31 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> The SystemDictionary is updated and read under the Compile_lock but this is unnecessary because the table is a concurrent hashtable, and the lock doesn't really synchronize any other compilation state.  The lock may have protected other state that Dependencies used in the past but has been removed.   See discussion in CR for more information.
> Tested with tier1-8.

Looks good. Thanks for taking care of it, Coleen.

FTR there are other redundant usages of `Compile_lock` in CI code.

src/hotspot/share/ci/ciEnv.cpp line 519:

> 517: 
> 518:   Klass* found_klass;
> 519:   if (!require_local) {

Since JVMCI needs the very same code, does it make sense to put it into a wrapper method?

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Marked as reviewed by vlivanov (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/13270#pullrequestreview-1367641286
PR Review Comment: https://git.openjdk.org/jdk/pull/13270#discussion_r1154920450