Integrated: 8251462: Simplify compilation policy

[Igor Veresov]

On Thu, 7 Jan 2021 18:43:51 GMT, Igor Veresov <iveresov at openjdk.org> wrote:

> This change removes the legacy compilation policy and an emulation mode to the tiered policy to simulate the old behavior with ```-XX:-TieredCompilation```. The change removed a bunch of interpreter code, devirtualizes the compilation policy API, adds a consistent way to query compiler configuration with the new ```CompilerConfig``` API.
> 
> I've tested this with hs-tier{1,2,3,4,5}. And also made sure it builds and works with C1/C2-Graal/AOT being enabled/disabled.
> 
> Since there are platform-specific changes I would greatly appreciate some help from the maintainers of the specific ports to verify the build and run basic smoke tests. I've already tested x64 and aarch64. Thanks!

This pull request has now been integrated.

Changeset: 15196325
Author:    Igor Veresov <iveresov at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/15196325
Stats:     5314 lines in 98 files changed: 1519 ins; 2994 del; 801 mod

8251462: Simplify compilation policy

Reviewed-by: cjplummer, kvn

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PR: https://git.openjdk.java.net/jdk/pull/1985