[jira] [Commented] (GROOVY-12288) Cache ClassWriter getCommonSuperClass lookups per class

[ASF GitHub Bot (Jira)]

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https://issues.apache.org/jira/browse/GROOVY-12288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18106972#comment-18106972
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ASF GitHub Bot commented on GROOVY-12288:
-----------------------------------------

sonarqubecloud[bot] commented on PR #2825:
URL: https://github.com/apache/groovy/pull/2825#issuecomment-5381935867

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   <!

> Cache ClassWriter getCommonSuperClass lookups per class
> -------------------------------------------------------
>
>                 Key: GROOVY-12288
>                 URL: https://issues.apache.org/jira/browse/GROOVY-12288
>             Project: Groovy
>          Issue Type: Improvement
>            Reporter: Daniel Sun
>            Priority: Major
>
> Bytecode generation uses an ASM {{ClassWriter}} with {{{}COMPUTE_FRAMES{}}}. 
> Frame computation calls {{getCommonSuperClass}} at every control-flow merge. 
> Groovy overrides that method so types still being compiled are resolved 
> through {{ClassNode}} ({{{}CompileUnit{}}}, generated inner classes, 
> {{{}ClassNodeResolver{}}}) rather than {{{}Class.forName{}}}.
> {{COMPUTE_FRAMES}} asks for the same binary-name pairs many times inside one 
> class. Each call converts slashes to dots, resolves two \{{ClassNode}}s, and 
> walks superclasses with isDerivedFrom. Class generation is about half of 
> compile wall time.
> h3. Approach
> Memoize both steps on the {{ClassWriter}} created by 
> {{{}CompilationUnit.createClassVisitor{}}}. One writer is allocated per 
> generated class and discarded afterwards, so the maps cannot go stale across 
> classes.
> ||Cache||Key||Value||
> |{{classNodeByName}}|binary name (dot form)|{{ClassNode}} (successful lookups 
> only)|
> |{{commonSuperByPair}}|canonical pair of internal names|internal name of the 
> common superclass|
> The key is order-independent: {{(A,B)}} and {{(B,A)}} share one entry. The 
> common-superclass algorithm is unchanged.
> h3. Impact
> Compile-time only. {{getCommonSuperClass}} results and generated bytecode 
> stay the same.
>  



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