StackMapTable format error: bad type array size in method

[Rafael Winterhalter]

I filed it here: https://bugs.openjdk.org/browse/JDK-8338661

Am Di., 20. Aug. 2024 um 11:32 Uhr schrieb Adam Sotona <
adam.sotona at oracle.com>:

> Hello,
>
> There is a problem in StackCounter calculation of maxLocals in combination
> with custom StackMapTableAttribute covering “dead code”.
>
>
>
> Feel free to report it as a bug or let me know and I’ll fill it.
>
>
>
> Thank you,
>
> Adam
>
>
>
> *From: *classfile-api-dev <classfile-api-dev-retn at openjdk.org> on behalf
> of Rafael Winterhalter <rafael.wth at gmail.com>
> *Date: *Monday, 19 August 2024 at 22:23
> *To: *classfile-api-dev <classfile-api-dev at openjdk.org>
> *Subject: *StackMapTable format error: bad type array size in method
>
> Hello,
>
> when testing some of the corner cases within the unit tests of Byte Buddy,
> I found some further errors when it comes to dead code and using
> ClassWriter. All those cases work when using ASM. As a reproducer, consider
> the following:
>
>
>     ClassFile classFile = ClassFile.*of*(ClassFile.StackMapsOption.*DROP_STACK_MAPS*);
>     byte[] bytes = classFile.build(ClassDesc.*of*("foo.Bar"), classBuilder -> classBuilder.withMethod(
>             "foo",
>             MethodTypeDesc.*ofDescriptor*("()J"),
>             0,
>             methodBuilder -> {
>                 methodBuilder.withCode(codeBuilder -> {
>                     codeBuilder.new_(ClassDesc.*of*(RuntimeException.class.getName()));
>                     codeBuilder.dup();
>                     codeBuilder.invokespecial(ClassDesc.*of*(RuntimeException.class.getName()),
>                             "<init>",
>                             MethodTypeDesc.*ofDescriptor*("()V"));
>                     codeBuilder.athrow();
>                     Label f2 = codeBuilder.newBoundLabel();
>                     codeBuilder.lstore(1);
>                     Label f3 = codeBuilder.newBoundLabel();
>                     codeBuilder.lload(1);
>                     codeBuilder.lreturn();
>                     codeBuilder.with(StackMapTableAttribute.*of*(List.*of*(
>                             StackMapFrameInfo.*of*(f2,
>                                     List.*of*(StackMapFrameInfo.ObjectVerificationTypeInfo.*of*(ClassDesc.*of*("foo.Bar"))),
>                                     List.*of*(StackMapFrameInfo.SimpleVerificationTypeInfo.*ITEM_LONG*)),
>                             StackMapFrameInfo.*of*(f3,
>                                     List.*of*(StackMapFrameInfo.ObjectVerificationTypeInfo.*of*(ClassDesc.*of*("foo.Bar")),
>                                             StackMapFrameInfo.SimpleVerificationTypeInfo.*ITEM_LONG*),
>                                     List.*of*())
>                     )));
>                 });
>             }));
>     new ClassLoader() {
>         @Override
>         protected Class<?> findClass(String name) throws ClassNotFoundException {
>             if (name.equals("foo.Bar")) {
>                 return defineClass(name, bytes, 0, bytes.length);
>             } else {
>                 return super.findClass(name);
>             }
>         }
>     }.findClass("foo.Bar").getMethods();
>
> It gives a class format error. Java agents sometimes have to process all
> kinds of strange byte code, so ideally these cases should be supported. Is
> this a bug in the stack map frame attribute writer?
>
>
>
> Thanks! Rafael
>
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