RFR: 8319813: Remove upper limit on number of compiler phases in phasetype.hpp [v5]

[Christian Hagedorn]

On Wed, 22 Nov 2023 11:22:33 GMT, Daniel Lundén <duke at openjdk.org> wrote:

>> This changeset removes the implicit upper limit on the number of compiler phases in `phasetype.hpp`. The limit was due to the 64-bit mask used in `Compile::should_print_phase`, causing the `assert(cpt < 64, "out of bounds");` in `phasetype.hpp` to trigger when increasing the number of phases to more than 64.
>> 
>> Changes:
>> - Replace the 64-bit mask with a bit map (`utilities/bitMap.hpp`).
>> - Clean up the `PhaseNameValidator` interface by allocating the mask internally.
>> - Move the check for whether a mask is non-zero ("is set") into `PhaseNameValidator`.
>> - Add a method `should_print_phase` to `DirectiveSet`, simplifying the `if`-condition in `Compile::should_print_phase`.
>> 
>> ### Testing
>> Platforms: windows-x64, linux-x64, linux-aarch64, macosx-x64, macosx-aarch64.
>> - `tier1`
>> - HotSpot parts of `tier2` and `tier3`
>
> Daniel Lundén has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix mask -> set in comments and remove empty line

Otherwise, looks good!

src/hotspot/share/opto/phasetype.hpp line 198:

> 196:   }
> 197:   bool is_valid() const { return _valid; }
> 198:   const char* what() const { return _bad; }

I suggest to either keep the old format with the return on a new line or add a new line between `phase_name_set()` and `is_valid()` to better separate it.

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Marked as reviewed by chagedorn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/16729#pullrequestreview-1744245785
PR Review Comment: https://git.openjdk.org/jdk/pull/16729#discussion_r1401958473