RFR (XS) 8185160 -XX:DumpLoadedClassList omits graal classes

[Ioi Lam]

On 10/17/17 9:04 PM, David Holmes wrote:
> Hi Ioi,
>
> On 18/10/2017 1:52 PM, Ioi Lam wrote:
>> http://cr.openjdk.java.net/~iklam/jdk10/8185160-dump-class-list-omits-graal.v01/ 
>>
>> https://bugs.openjdk.java.net/browse/JDK-8185160
>>
>> Summary:
>>
>> DumpLoadedClassList skips classes that can't be stored into the CDS
>> archive. For boot and platform loaders, only classes from the JRT image
>> are listed.
>>
>> The test for "is this class from JRT image" was insufficient. It
>> checked only classes whose source ends with "...../modules". For the
>> platform loader, which loads the graal classes, the source is in the
>> form "jrt:/jdk.internal.vm.compiler".
>>
>> The fix is to also check for a "jrt:" prefix.
>
> So ./share/classfile/classLoader.hpp:
>
> static bool is_jrt(const char* name) { return string_ends_with(name, 
> MODULES_IMAGE_NAME); }
>
> is a badly named function or just plain broken?
>

I've renamed all the is_jrt() functions to is_modules_image(), so it's 
clear as to what it does.

See 
http://cr.openjdk.java.net/~iklam/jdk10/8185160-dump-class-list-omits-graal.v02/


>> I also restructured the code to make it easier to read -- the nesting 
>> of || and && is hard to follow.
>>
>> The original code had a subtle bug with the "!" operator:
>>
>> 5938   if (((class_loader == NULL && 
>> !ClassLoader::contains_append_entry(stream->source())) ||
>> 5939 SystemDictionary::is_platform_class_loader(class_loader)) &&
>> 5940       !ClassLoader::is_jrt(stream->source())) {
>>
>> So if (class_loader == NULL && 
>> ClassLoader::contains_append_entry(stream->source()) was true,
>> the class would NOT be skipped.
>>
>> The new version removes the "!".
>
> So there should be an updated test to trigger the original bug.
>

I added a test case, but it's in the closed repo for now (since the test 
case uses utilities in the closed AppCDS tests). This test will be 
opened as part of JDK-8185996

Thanks
- Ioi

> Thanks,
> David
>
>> Thanks
>> - Ioi