OPAL-Project/Lobby

Discussion of all aspects related to the OPAL library (www.opal-project.de)

Alexander Gössl

@majestocx

Ok i have the tacAI Variable how can i get the Text representation of the TAC ?

Alexander Gössl

@majestocx

Is tacAI not applicable on a class?

def getTacForClass(tacForClass : TACForClass) : String = {
val tacAI = project.get(DefaultTACAIKey)
val tacClass = project.allClassFiles.find(_.fqn == tacForClass.fqn).get
tacAI(tacClass);
}

Florian Kübler

@florian-kuebler

No the TAC is a function from Method to TACode

Alexander Gössl

@majestocx

ok is there a way to get from a class to tac in txt format ?

Michael Eichberg

@Delors

Yes… you can use the ToTxt class which provides a respective function.

For a concrete usage of that class see “org.opalj.tac.TAC”.

The latter class also provides a command-line interface to get the TAC of a specific method.

 val aiResult = BaseAI(m, d)
                        val tac @ TACode(params, code, _, cfg, ehs, _) =
                            TACAI(m, project.classHierarchy, aiResult)(Nil)
                        if (toString) Console.out.println(m.toJava(tac.toString))

                        (
                            ToTxt(params, code, cfg, skipParams = false, true, true).mkString("\n”),

does this help?

Alexander Gössl

@majestocx

yes

thank you

Alexander Gössl

@majestocx

I have another question: Is the fqn of a class like this: org.opalj.tac.TAC ok like this: org/opalj/tac/TAC or none of it?

Michael Eichberg

@Delors

The latter - if you want the first variant call „toJava“

Michael Eichberg

@Delors

To get a specific class file belonging to a project use project.classFile(ObjectType(<Name of class in fqn>)). This is a constant operation; using find is linear operation!

kebiro

@kebiro

Hello,

we had a little chat about this before: there is possibly a bug in OPAL regarding an escaping backslash. It seems to escape them before outputting the text. I'll provide an example.

This is the original string in String.java

In String.classit looks like this:

Alexander Gössl

@majestocx

ok i got my method working thanks all for your help!

kebiro

@kebiro

However, the TAC output looks like this:

There is only a single backslash left, hence the following " is escaped, so until another " appears everything will be seen as a string.

Michael Eichberg

@Delors

Yep

Alexander Gössl

@majestocx

Ok im working on this again so i have some more questions.
I try to use the MethodDescriptor object like this: MethodDescriptor("(): void").
I get this exception:
[info] java.lang.IllegalArgumentException: : void is not a valid field type descriptor
[info] at org.opalj.br.FieldType$.apply(Type.scala:361)
[info] at org.opalj.br.ReturnType$.apply(Type.scala:278)
[info] at org.opalj.br.MethodDescriptor$.apply(MethodDescriptor.scala:667)
Is my argument wrong?

I also tried this: MethodDescriptor("(java.lang.String[]): void") but i get java.lang.IllegalArgumentException: j is not a valid field type descriptor

I get same results with / instead of .

Michael Reif

@mreif

This is indeed wrong. When passing a String argument to a MethodDescriptor you have to pass it in JVM notation.

MethodDescriptor("([Ljava/lang/String;)V")

However, I would not recommend doing this because it's rather error-prone. You should use the other apply methods MethodDescriptor offers. Here are two examples:

MethodDescriptor(ArrayType(ObjectType.String), VoidType) // first parameter represents the parameter list, the second the return type MethodDescriptor(RefArray(LongType,ByteType,ObjectType.String), BooleanType) // a method with (long, byte, String): boolean

You can find more example in OPAL's MethodDescriptor class itself

Alexander Gössl

@majestocx

ok i will give it a try

thanks for your answer

Alexander Gössl

@majestocx

it works :)

Michael Reif

@mreif

Good :-)

Alexander Gössl

@majestocx

@florian-kuebler I implemented your snippeet about the call graph. I have org.opalj.fpcf.EOptionP[org.opalj.br.DefinedMethod,org.opalj.br.fpcf.cg.properties.CallersProperty]. Is there a method to get from that to an svg?

Florian Kübler

@florian-kuebler

Unfortunately, the answer is no

Alexander Gössl

@majestocx

Alexander Gössl

@majestocx

Is it possible to get the TAC from a class inside the jdk ? Like java/lang/String ?

Florian Kübler

@florian-kuebler

If the JDK is part of the project, it works just as for any other class. The File constant org.opalj.bytecode.RTJar, is the File of the current Java Runtime.

Alexander Gössl

@majestocx

Ok thanks for the information @florian-kuebler. I tried to get the TAC but method.body seems to be None. The jdk is part of the Analysis and libraryClassFilesAreInterfacesOnly is set to false.

Michael Eichberg

@Delors

How do you load the library? The method body should only be None if the method doesn’t have one (native or abstract) or if it is discarded while loading it. BTW libraryClassFilesAreInterfacesOnly actually doesn’t change how the classes are loaded - it basically reflects how the classes are expected to be loaded. That is, it might be possible that the “discarding" loader was used but libraryClassFilesAreInterfacesOnly is still false.

Alexander Gössl

@majestocx

Ok i will check wether the method is native / abstract. This is how the librarie is loaded:

val libraryClassFiles = Java9LibraryFramework.AllClassFiles(opalInit.libraries.map(new File(_)) :+ org.opalj.bytecode.RTJar )

Michael Eichberg

@Delors

ok…. Java9LibraryFramework kills the method bodies

you should use the “normal” Java9Framework

it is interessting that libraryClassFilesAreInterfacesOnly is false … there is clearly some issue somewhere!

Alexander Gössl

@majestocx

Ok now my Tests need some extra Memory but i still get the same exception:

nfo] - Load Project with jdk and libraryClassFilesAre not InterfacesOnly FAILED
[info] "java.util.NoSuchElementException: None.get
[info] at scala.None$.get(Option.scala:366)
[info] at scala.None$.get(Option.scala:364)
[info] at org.opalj.tac.TACNaive$.apply(TACNaive.scala:70)
[info] at org.opalj.tac.ToTxt$.$anonfun$apply$9(ToTxt.scala:319)
[info] at scala.Option.getOrElse(Option.scala:138)
[info] at org.opalj.tac.ToTxt$.apply(ToTxt.scala:318)
[info] at opal.extension.vscode.OPALProject.$anonfun$getTacForClass$2(OPALProject.scala:124)
[info] at opal.extension.vscode.OPALProject.$anonfun$getTacForClass$2$adapted(OPALProject.scala:116)
[info] at org.opalj.collection.immutable.RefArray.foreach(RefArray.scala:289)
[info] at opal.extension.vscode.OPALProject.getTacForClass(OPALProject.scala:116)

Michael Eichberg

@Delors

First - have you tried using the AI based variant of the TAC instead of TACNaive? If the first one works, it is a bug in the latter :-)

If does work with TACAI but doesn’t work with TACNaive can you tell which class causes the troubles?

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