Request for review (S) 6780143: hs203t003 hits SIGSEGV/EXCEPTION_ACCESS_VIOLATION with -XX:+UseCompressedOops

[Coleen Phillimore]

Thanks to Tom for pointing out what was really killing r12, I have a new 
webrev with a better fix and better summary.

Summary: Using r12 as temporary register around call_VM trashes heapbase 
because call_VM doesn't always return immediately to following code (eg 
forward_exception, popframe and early return support).

open webrev at http://cr.openjdk.java.net/~coleenp/6780143/   (hit reload)
bug link at http://bugs.sun.com/view_bug.do?bug_id=6780143

Thanks,
Coleen

Tom Rodriguez wrote:
> The changes look ok but what code was killing r12?  All the existing reinit_heapbase calls are because we're using the callee-saved-ness of r12 to keep something else alive but that's no true here.
>
> tom
>
> On Nov 18, 2010, at 12:20 PM, coleen phillimore wrote:
>
>   
>> Summary: missing reinit_heapbase() when popframe support jumps back into interpreter from C code.
>>
>> open webrev at http://cr.openjdk.java.net/~coleenp/6780143/
>> bug link at http://bugs.sun.com/view_bug.do?bug_id=6780143
>>
>> Tested by running our jvmti tests including the failing test.
>>
>> Coleen
>>     
>
>