RFR 8054008: Using -XX:-LazyBootClassLoader crashes with ACCESS_VIOLATION on Win 64bit

[Jiangli Zhou]

Hi Roland,

Thank you for the review. Please see comments and questions below.

On 11/07/2014 05:16 AM, Roland Westrelin wrote:
> Hi Jiangli,
>
>> Please review the following changes that fix the crash with -XX:-LazyBootClassLoader on windows x64 platforms (fastdebug only). During VM initialization,  current_stack_pointer() could be called before the VM generates stub routines. The generated get_previous_sp routine cannot be used during that time, use the estimated value for the sp value instead. The x86 implementation is unaffected by the change and always returns the estimated sp value as before.
>>
>> bug: https://bugs.openjdk.java.net/browse/JDK-8054008
>> webrev: http://cr.openjdk.java.net/~jiangli/8054008/webrev/
>>
>> Tested with JPRT and ExtBadJAR test.
> But if what os::current_stack_pointer() returns is no longer “accurate”, aren’t you at risk of hitting the assert in  os::verify_stack_alignment()? Shouldn’t you skip the assert entirely if the routine is not yet available?

For x64, it still returns the "accurate" value once the routine is 
generated. Before the routine is ready, it gives the estimate, which 
might have the risk of upsetting the assert as you suggested. I have a 
few questions. Have you run into the case where the estimate might 
trigger the assertion on x64? What about x86, why that's not handled the 
same as x64?

>
> Also why not make that change on all platform to improve robustness while you’re doing this?

Thank you for the suggestion. Sound good. I'll look into this. Is there 
a global flag that indicates the stub routines are generated?

Thanks,
Jiangli

>
> Roland.