RFR: 8293287 add ReplayReduce flag [v3]

[Tobias Hartmann]

On Sat, 3 Sep 2022 21:56:50 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Add an experimental flag to help developers "reduce" a replay file.
>> 
>> As a first step, I plan to simulate reduced inlining. This will output multiple "compile" lines as if the first level of inlining never happened:
>> A --> B --> C
>> A --> D --> E
>> becomes
>> B --> C
>> D --> E
>> Developers can repeat iteratively until the replay crash no longer reproduces.
>
> Dean Long has updated the pull request incrementally with one additional commit since the last revision:
> 
>   remove support for pre-2013 replay files

I'm wondering if this functionality should really be part of the VM. Wouldn't a simple script that regex-parses the compile statement of the replay file, iteratively removes inlines and runs replay compilation to check if the issue still reproduces, be more powerful and easier to maintain? It could be combined with also removing class loading statements.

src/hotspot/share/opto/compile.cpp line 4583:

> 4581:     return;
> 4582:   }
> 4583:   // Enable interative replay file reduction

Suggestion:

  // Enable iterative replay file reduction

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PR: https://git.openjdk.org/jdk/pull/10134