RFR: 8157490: null stream->source() no longer causes error with -Xlog:class+load

[Lois Foltan]

On 5/26/2016 2:07 PM, Max Ockner wrote:
> Hello,
>
> Please review this very small fix for class+load logging with modules.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8157490
> Webrev: http://cr.openjdk.java.net/~mockner/8157490/
>
> Summary:  The JCK test 
> vm/jni/DefineClass/dfcl001/dfcl00101m1/dfcl00101m1 hit a SIGSEGV in 
> the logging section at the end of 
> ClassFileParser::fill_instance_klass(). With the addition of modules, 
> this logging section now uses
>
>     strlen(stream->source())
>
> to compute some of the module related parameters that it needs. This 
> SIGSEGV originated from the above line being executed with a null 
> stream source.

Hi Max,

I think you change is correct, but I would like to suggest changing the 
code even further.  Currently the code between line #5352-5360 does a 
complicated check to see if the module's name is part of the java 
runtime image file and only sets the local variable "module_name" if it 
is.  So, only module names that are defined within the java runtime 
image file are printed out in the logging. We should print out all 
modules' names, not just the ones in the jimage file.  So please try 
removing lines #5352-5360 and set the local variable to:

     const char* module_name = (module_entry->name() == NULL) ? 
UNNAMED_MODULE : module_entry->name()->as_C_string();

The local variable "module_entry" is already checked at line #5310 to 
make sure it is set to a non-NULL value.

Thanks,
Lois

>
> Tested with vm/jni/DefineClass/dfcl001/dfcl00101m1/dfcl00101m1
>
> Thanks,
> Max