[rvm-issues] [jira] (RVM-957) Optimizing compiler (at O1+) produces incorrect code

[David G. (JIRA) <ji...@co...>]

     [ https://jira.codehaus.org/browse/RVM-957?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

David Grove updated RVM-957:
----------------------------

    Fix Version/s: 3.1.3
         Assignee: David Grove
    
> Optimizing compiler (at O1+) produces incorrect code
> ----------------------------------------------------
>
>                 Key: RVM-957
>                 URL: https://jira.codehaus.org/browse/RVM-957
>             Project: RVM
>          Issue Type: Bug
>          Components: Compiler: Optimizing
>    Affects Versions: 3.1.2
>         Environment: host.name=ia32-linux
> config.name=production
>            Reporter: Andreas Sewe
>            Assignee: David Grove
>             Fix For: 3.1.3
>
>         Attachments: scalac.ca
>
>
> The optimizing compiler (at levels O1 or higher) seems to produce incorrect code for a method from the {{scalac}} benchmarks of the Scala benchmark suite found at http://repo.scalabench.org/snapshots/org/scalabench/benchmarks/scala-benchmark-suite/0.1.0-SNAPSHOT/scala-benchmark-suite-0.1.0-20120216.103539-3.jar.
> When run with {{./dist/production_ia32-linux/rvm -X:aos:enable_recompilation=false -X:aos:initial_compiler=opt -X:irc:O1 -jar scala-benchmark-suite-0.1.0-20120216.103539-3.jar scalac --preserve}} the following exception ensues:
> {quote}
> Caused by: java.lang.ClassCastException
>    at scala.tools.nsc.typechecker.Infer$class.isFullyDefined(Infer.scala:107)
>    at scala.tools.nsc.Global$analyzer$.isFullyDefined(Global.scala:301)
>    at scala.tools.nsc.typechecker.Infer$Inferencer$$anonfun$methTypeArgs$1.apply(Infer.scala:629)
>    at scala.tools.nsc.typechecker.Infer$Inferencer$$anonfun$methTypeArgs$1.apply(Infer.scala:628)
>    at scala.collection.LinearSeqOptimized$class.foreach(LinearSeqOptimized.scala:61)
>    at scala.collection.immutable.List.foreach(List.scala:45)
>    at scala.tools.nsc.typechecker.Infer$Inferencer.methTypeArgs(Infer.scala:628)
>    at scala.tools.nsc.typechecker.Infer$Inferencer.inferMethodInstance(Infer.scala:1155)
>    at scala.tools.nsc.typechecker.Typers$Typer.doTypedApply(Typers.scala:2501)
>    at scala.tools.nsc.typechecker.Typers$Typer.typedApply$1(Typers.scala:3380)
>    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:4049)
>    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4203)
>    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4265)
>    at scala.tools.nsc.typechecker.Typers$Typer.typedFunction(Typers.scala:2072)
>    at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:3921)
>    at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:4203)
>    ...
> {quote}
> When limiting oneself to {{-X:aos:initial_compiler=opt -X:irc:O1}} or {{-X:aos:initial_compiler=base}}, this exception does not show up.
> By instrumenting {{RuntimeEntrypoints.deliverHardwareException}} I was able to determine the problematic {{checkcast}} instruction; it's located at bytecode index 324 in {{scala.tools.nsc.typechecker.Infer$class.isFullyDefined(scala.tools.nsc.typechecker.Analyzer, scala.tools.nsc.symtab.Types$Type)}}:
> {quote}
> > javap -c -l -classpath scratch/jar/scala-compiler-2.8.1.jar scala.tools.nsc.typechecker.Infer\$class
> public static boolean isFullyDefined(scala.tools.nsc.typechecker.Analyzer, scala.tools.nsc.symtab.Types$Type);
>   Code:
>    ...
>    319: aload   8
>    321: invokevirtual   #335; //Method scala/Tuple2._1:()Ljava/lang/Object;
>    324: checkcast       #104; //class scala/tools/nsc/symtab/Types$Type
>    ...
>   LineNumberTable: 
>    line 296: 304
>    line 107: 308
>    line 119: 341
>    ...
> {quote}
> In {{BC2IR}} this {{checkcast}}, unlike some others in {{isFullyDefined}} is not skipped.
> As this bug is "local" to the {{isFullyDefined}} method, it is possible to use a very short compiler advice file (attached) requesting just this method to be compiled to reproduce the bug: {{./dist/production_ia32-linux/rvm -X:aos:initial_compiler=base -X:aos:enable_precompile=true -X:aos:enable_recompilation=false -X:aos:cafi=scalac.ca -jar  scala-benchmark-suite-0.1.0-20120216.103539-3.jar scalac --preserve}}

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