RFR: 8271461: CompileCommand support for hidden class methods [v2]

[Jie Fu]

On Fri, 30 Jul 2021 02:01:55 GMT, Jie Fu <jiefu at openjdk.org> wrote:

>> Hi all,
>> 
>> We'd like to improve the CompileCommand to support hidden class methods, which is helpful for debugging and perfmance analysis.
>> 
>> Current implementation of CompileCommand doesn't work for hidden class methods.
>> For example, if you run with `java -Xcomp -Xbatch -XX:+PrintCompilation`
>> The following hidden class methods were compiled:
>> 
>>    5317 1573    b  3       java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run (8 bytes)
>>    5318 1574    b  4       java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run (8 bytes)
>>    6735 1938    b  3       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$2/0x0000000801041e80::run (12 bytes)
>>    6736 1939    b  4       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$2/0x0000000801041e80::run (12 bytes)
>>    7060 2029    b  3       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$58/0x800000060::run (8 bytes)
>>    7061 2030    b  4       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$58/0x800000060::run (8 bytes)
>>    7688 2153    b  3       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$4/0x0000000801043218::run (16 bytes)
>>    7688 2154    b  4       java.util.ResourceBundle$ResourceBundleProviderHelper$$Lambda$4/0x0000000801043218::run (16 bytes)
>> 
>> 
>> Then people may want to exclude the compilation of `java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run` like this
>> 
>> -XX:CompileCommand=exclude,'java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run'
>> 
>> 
>> But unfortunately, it doesn't work.
>> 
>> CompileCommand: An error occurred during parsing
>> Error: Method pattern uses '/' together with '::'
>> Line: 'exclude,java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run'
>> 
>> Usage: '-XX:CompileCommand=<option>,<method pattern>' - to set boolean option to true
>> Usage: '-XX:CompileCommand=<option>,<method pattern>,<value>'
>> Use:   '-XX:CompileCommand=help' for more information and to list all option.
>> 
>> 
>> The failing reason is that the name of `java.util.ResourceBundle$$Lambda$1/0x00000008010413c8::run` is actually `java.util.ResourceBundle$$Lambda$1+0x00000008010413c8::run` in the VM.
>> But "+" had been replaced with "/" when it was printed by PrintCompilation [1].
>> 
>> So for a hidden class method, "/" should be replaced with "+" to make CompileCommand work.
>> 
>> Thanks.
>> Best regards,
>> Jie
>> 
>> 
>> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/oops/klass.cpp#L685
>
> Jie Fu has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use isdigit

> so CompileCommand has supported inner classes, this is dedicated to the hidden class?
> 
> I think wildcard '*' is a practical way for dynamic hidden class names. One thing I am not so sure is that why you only handle `have_colon`? eg. is the following command legitimate?
> 
> ```
> java  -XX:CompileCommand='exclude,java.util.ResourceBundle$$Lambda$1/*.run'  -version
> ```



> so CompileCommand has supported inner classes, this is dedicated to the hidden class?
> 
> I think wildcard '*' is a practical way for dynamic hidden class names. One thing I am not so sure is that why you only handle `have_colon`? eg. is the following command legitimate?
> 
> ```
> java  -XX:CompileCommand='exclude,java.util.ResourceBundle$$Lambda$1/*.run'  -version
> ```

This is because PrintCompilation doesn't print the format you mentioned above.
So I don't think people would like to use that style and not want to make things too complicated.

You may argue that some people may still do that by transforming the PrintCompilation output string by hand.
Then, I would ask why not also replacing the '/' with '+' by hand?

But if you really think it's worth enough to support that style, I can still do that.
Thanks.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4926