[jira] [Created] (GROOVY-10156) Unreachable bytecode in switch statement

["Damir Murat (Jira)" <ji...@apache.org>]

Damir Murat created GROOVY-10156:
------------------------------------

             Summary: Unreachable bytecode in switch statement
                 Key: GROOVY-10156
                 URL: https://issues.apache.org/jira/browse/GROOVY-10156
             Project: Groovy
          Issue Type: Improvement
          Components: Compiler
    Affects Versions: 3.0.8
         Environment: JVM: 11.0.11 (Oracle Corporation 11.0.11+9-LTS-194)
OS: Mac OS X 10.16 x86_64
            Reporter: Damir Murat


When switching over an enum, and for two or more case branches, groovy generates unreachable bytecode for each case branch except the last one.

For example
{code:java}
package mypackage
import groovy.transform.CompileStatic

@CompileStatic
class SwitchDemo {
  void mySwitchMethod(MyEnum myEnum) {
    switch (myEnum) {
      case MyEnum.ONE:
        println "ONE"
        break
      case MyEnum.TWO:
        println "TWO"
        break
      case MyEnum.THREE:
        println "TWO"
        break
      default:
        println "default"
        break
    }
  }
}

@CompileStatic
enum MyEnum {
  ONE, TWO, THREE
}
{code}
generates bytecode sequences like
{code:java}
...
   L8
   L9
    LINENUMBER 12 L9
    GOTO L10
   L3
   L11
    LINENUMBER 12 L11
    ALOAD 2
    GETSTATIC mypackage/MyEnum.TWO : Lmypackage/MyEnum;
    INVOKESTATIC org/codehaus/groovy/runtime/ScriptBytecodeAdapter.isCase (Ljava/lang/Object;Ljava/lang/Object;)Z
    IFEQ L12
   L10
...
{code}
It looks like the first four lines above are not necessary. This results in
{noformat}
nop, nop, athrow
{noformat}
sequences in generated java bytecode.

It would be great if this can be cleaned up and fixed. My scenario is related to JaCoCo reports which are not accurate and a bit confusing for switch statements.

Tnx



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