Got: IllegalArgumentException: Could not resolve class

[Adam Sotona]

Your compiler reached the complexity where you reference generated classes from other generated classes.
Class-File API in certain circumstances needs to know some information about the classes referenced from the generated bytecode.
Such information is provided in ClassHierarchyInfo<https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/classfile/ClassHierarchyResolver.ClassHierarchyInfo.html> using functional interface ClassHierarchyResolver<https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/classfile/ClassHierarchyResolver.html>.

By default<https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/classfile/ClassHierarchyResolver.html#defaultResolver()> is the information obtained from system class loader. However, the classes you generate are probably not yet known to the system class loader.
You should specify a custom ClassHierarchyResolver<https://docs.oracle.com/en/java/javase/22/docs/api/java.base/java/lang/classfile/ClassHierarchyResolver.html> for your compiler as a Class-File API option `ClassFile.of(ClassFile.ClassHierarchyResolverOption.of(...))`.

Here you have multiple options how to provide the missing information using combinations of ClassHierarchyResolver factory methods and custom code:

For example, if the required classes have been already generated and you can provide a physical access to them, you can compose the ClassHierarchyResolver this way:
`ClassHierarchyResolver.defaultResolver().orElse(ClassHierarchyResolver. ofResourceParsing(Function<ClassDesc, InputStream>).cached())`

Or if you know all the generated classes in advance, you can provide the missing info about the generated classes in a set and map form:
`ClassHierarchyResolver.defaultResolver().orElse(ClassHierarchyResolver. of(Collection<ClassDesc> interfaces, Map<ClassDesc, ClassDesc> classToSuperClass))`

Or in a form of dynamic direct implementation of the ClassHierarchyResolver:
`ClassHierarchyResolver.defaultResolver().orElse(classDesc -> isInterface ? : ClassHierarchyInfo.ofInterface() : ClassHierarchyInfo.ofClass(ClassDesc superClass))`



From: classfile-api-dev <classfile-api-dev-retn at openjdk.org> on behalf of Øystein Myhre Andersen <o.myhre at gmail.com>
Date: Sunday, 28 April 2024 at 12:53
To: classfile-api-dev at openjdk.org <classfile-api-dev at openjdk.org>
Subject: Got: IllegalArgumentException: Could not resolve class
I'm writing a compiler for Simula (the very first oo language).
Simula is block-oriented with nested blocks and each block is compiled into a classFile.
At a certain level in the hierarchy I get an exception at the end of the classfile building.

Exception in thread "main" java.lang.IllegalArgumentException:
             Could not resolve class adHoc000_adHoc000_PBLK39_Floor_activateIdleLift

at java.base/jdk.internal.classfile.impl.ClassHierarchyImpl.resolve(ClassHierarchyImpl.java:75)
at java.base/jdk.internal.classfile.impl.ClassHierarchyImpl.isInterface(ClassHierarchyImpl.java:85)
at java.base/jdk.internal.classfile.impl.StackMapGenerator$Type.mergeReferenceFrom(StackMapGenerator.java:1363)
at java.base/jdk.internal.classfile.impl.StackMapGenerator$Type.mergeFrom(StackMapGenerator.java:1331)
at java.base/jdk.internal.classfile.impl.StackMapGenerator$Frame.merge(StackMapGenerator.java:1193)
at java.base/jdk.internal.classfile.impl.StackMapGenerator$Frame.checkAssignableTo(StackMapGenerator.java:1135)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.checkJumpTarget(StackMapGenerator.java:280)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.processExceptionHandlerTargets(StackMapGenerator.java:678)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.processBlock(StackMapGenerator.java:667)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.processMethod(StackMapGenerator.java:440)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.generate(StackMapGenerator.java:317)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.<init>(StackMapGenerator.java:243)
at java.base/jdk.internal.classfile.impl.StackMapGenerator.of(StackMapGenerator.java:156)
at java.base/jdk.internal.classfile.impl.DirectCodeBuilder$4.generateStackMaps(DirectCodeBuilder.java:331)
at java.base/jdk.internal.classfile.impl.DirectCodeBuilder$4.tryGenerateStackMaps(DirectCodeBuilder.java:340)
at java.base/jdk.internal.classfile.impl.DirectCodeBuilder$4.writeBody(DirectCodeBuilder.java:382)
at java.base/jdk.internal.classfile.impl.UnboundAttribute$AdHocAttribute.writeTo(UnboundAttribute.java:914)
at java.base/jdk.internal.classfile.impl.AttributeHolder.writeTo(AttributeHolder.java:56)
at java.base/jdk.internal.classfile.impl.DirectMethodBuilder.writeTo(DirectMethodBuilder.java:156)
at java.base/jdk.internal.classfile.impl.BufWriterImpl.writeList(BufWriterImpl.java:207)
at java.base/jdk.internal.classfile.impl.DirectClassBuilder.build(DirectClassBuilder.java:181)
at java.base/jdk.internal.classfile.impl.ClassFileImpl.build(ClassFileImpl.java:114)
... ...

Is this a known problem?
What am I doing wrong?

I am attaching a file with an edited trace leading up to the exception.

- Øystein Myhre Andersen
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