[lworld] RFR: 8261019: [lworld] valhalla/valuetypes/QTypeDescriptorTest.java "Illegal class name "QLine; " in class file $Proxy5" [v2]

[Yang Yi]

> Hi all,
> 
> QTypeDescriptorTest.java[0] also fails on my machine, this is occurred after merging JDK[1], I did some investigation. The root cause of the problem is that after the JDK was merged[1], the value of the constant CONSTANT_CLASS_DESCRIPTORS was changed from 61 to 62, but the major version of the class bytes generated dynamically by java.lang.reflect.ProxyGenerator was not updated simultaneously, it remained at the value 60:
> private byte[] generateClassFile() {
>   // V16 == 60
>   visit(V16, accessFlags, dotToSlash(className), null,
>           JLR_PROXY, typeNames(interfaces));
> ...
> }
> ClassFileParser::verify_legal_class_name would go to an unexpected branch, which causes ClassFormatError.
> void ClassFileParser::verify_legal_class_name(...) const {
>   ...
>   if (length > 0) {
>     ...
>     // read _major_version(60) from dynamically generated class bytes,
>     // compare with updated CONSTANT_CLASS_DESCRIPTORS(61)
>     else if (_major_version >= CONSTANT_CLASS_DESCRIPTORS && bytes[length - 1] == ';' ) {
>       // EXPECTED HERE
>       legal = verify_unqualified_name(bytes + 1, length - 2, LegalClass);
>     } else {
>       // GO TO HERE
>       legal = verify_unqualified_name(bytes, length, LegalClass);
>     }
>   }
>   if (!legal) {
>     ResourceMark rm(THREAD);
>     assert(_class_name != NULL, "invariant");
>     Exceptions::fthrow(
>       THREAD_AND_LOCATION,
>       vmSymbols::java_lang_ClassFormatError(),
>       "Illegal class name "%.*s" in class file %s", length, bytes,
>       _class_name->as_C_string()
>     );
>     return;
>   }
> }
> JDK-826101 suspects that JDK-8261021[2]  has the same problem since their exception messages are relatively similar. But according to their stack traces, they might be caused by different but related problems.
> 
> [0] https://bugs.openjdk.java.net/browse/JDK-8261019
> [1] https://github.com/openjdk/valhalla/pull/316
> [2] https://bugs.openjdk.java.net/browse/JDK-8261021

Yang Yi has updated the pull request incrementally with one additional commit since the last revision:

  Update full name

-------------

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/320/files
  - new: https://git.openjdk.java.net/valhalla/pull/320/files/65d376dd..04836bb7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=320&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=320&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/320.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/320/head:pull/320

PR: https://git.openjdk.java.net/valhalla/pull/320