GROOVY-12065: Implement peephole optimization for bytecode generation

[daniellansun]

https://issues.apache.org/jira/browse/GROOVY-12065

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 1.50.

Benchmark suite	Current: 2a55a90	Previous: 5499e6c	Ratio
org.apache.groovy.bench.dispatch.CallsiteBench.dispatch_3_polymorphic_java	6381.848447984659 ops/ms	2061.672284547263 ops/ms	3.10
org.apache.groovy.bench.dispatch.CallsiteBench.dispatch_8_megamorphic_java	6026.931429013922 ops/ms	1557.261659873728 ops/ms	3.87
org.apache.groovy.bench.AckermannBench.java ( {"n":"5"} )	0.10029679168967505 ms/op	0.05051886991481147 ms/op	1.99
org.apache.groovy.bench.AckermannBench.java ( {"n":"6"} )	0.4584048799045104 ms/op	0.2130785099853715 ms/op	2.15
org.apache.groovy.bench.AckermannBench.java ( {"n":"7"} )	1.9316165215476144 ms/op	0.9758806863895909 ms/op	1.98
org.apache.groovy.bench.AryBench.groovyCS ( {"n":"1000"} )	0.1382858471799125 ms/op	0.057643790485718605 ms/op	2.40
org.apache.groovy.bench.AryBench.groovyCS ( {"n":"1000000"} )	267.78055662500003 ms/op	114.49380287669935 ms/op	2.34
org.apache.groovy.bench.AryBench.java ( {"n":"1000"} )	0.13760981117671897 ms/op	0.08895810367001782 ms/op	1.55
org.apache.groovy.bench.AryBench.java ( {"n":"1000000"} )	268.15117947500005 ms/op	112.86152071045751 ms/op	2.38

This comment was automatically generated by workflow using github-action-benchmark.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 87.17949% with 50 lines in your changes missing coverage. Please review.
✅ Project coverage is 68.3569%. Comparing base (c92ba5f) to head (2a55a90).

Files with missing lines	Patch %	Lines
.../classgen/asm/PeepholeOptimizingMethodVisitor.java	87.2629%	31 Missing and 16 partials ⚠️
...rg/codehaus/groovy/classgen/AsmClassGenerator.java	81.8182%	2 Missing ⚠️
...org/codehaus/groovy/classgen/asm/OperandStack.java	83.3333%	1 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##               master      #2591        +/-   ##
==================================================
+ Coverage     68.3072%   68.3569%   +0.0497%     
- Complexity      33391      33524       +133     
==================================================
  Files            1518       1519         +1     
  Lines          126871     127222       +351     
  Branches        23000      23026        +26     
==================================================
+ Hits            86662      86965       +303     
- Misses          32526      32558        +32     
- Partials         7683       7699        +16     

Files with missing lines	Coverage Δ
...g/codehaus/groovy/classgen/asm/BytecodeHelper.java	87.1935% <100.0000%> (-0.7518%)	⬇️
...va/org/codehaus/groovy/classgen/asm/MopWriter.java	85.8974% <100.0000%> (+0.1831%)	⬆️
...org/codehaus/groovy/classgen/asm/OperandStack.java	77.6398% <83.3333%> (-0.9730%)	⬇️
...rg/codehaus/groovy/classgen/AsmClassGenerator.java	85.1852% <81.8182%> (+0.0324%)	⬆️
.../classgen/asm/PeepholeOptimizingMethodVisitor.java	87.2629% <87.2629%> (ø)

... and 5 files with indirect coverage changes

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[github-actions]

JMH summary — classic (commit 0cda4cd)

Speedup vs trailing 90-day baseline on gh-pages. Higher = faster.
1.00 = in line with history. Per-benchmark ratio, geomean within group.
Time-per-op units inverted so direction is consistent.

Group	Speedup	n
bench	1.018 ×	26
core	0.979 ×	77
grails	0.985 ×	80

_{Baseline: dev/bench/jmh/<part>/classic/data.js on gh-pages, trailing 90 days. Daily dashboard · Per-suite raw data}

[github-actions]

JMH summary — indy (commit 0cda4cd)

Speedup vs trailing 90-day baseline on gh-pages. Higher = faster.
1.00 = in line with history. Per-benchmark ratio, geomean within group.
Time-per-op units inverted so direction is consistent.

Group	Speedup	n
bench	1.000 ×	26
core	0.991 ×	77
grails	1.019 ×	80

_{Baseline: dev/bench/jmh/<part>/indy/data.js on gh-pages, trailing 90 days. Daily dashboard · Per-suite raw data}

[testlens-app]

✅ All tests passed ✅

⚠️ TestLens detected flakiness ⚠️

Test Summary

Check	Project/Task	Test	Runs
Build and test / lts (17, macos-latest)	:test	ActorTest > testScheduleAtFixedRateCancelStopsFurtherFires()	❌ 🚫

🏷️ Commit: 2a55a90
▶️ Tests: 103752 executed
⚪️ Checks: 60/60 completed

---

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[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
89.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[eric-milles]

Doesn't this require LCONST_0 and so on so the operand stack type is correct?

[blackdrag]

Maybe it was different when most of the bytecode code was written, but current version of asm actually handle the special case internally: https://asm.ow2.io/javadoc/org/objectweb/asm/MethodVisitor.html#visitLdcInsn(java.lang.Object) - AFAIK