review for 7104960: JSR 292: +VerifyMethodHandles in product JVM can overflow buffer

Tom Rodriguez tom.rodriguez at
Fri Nov 4 10:54:05 PDT 2011

On Nov 3, 2011, at 10:49 PM, John Rose wrote:

> That's good.
> The xtty output should delimit the attribute values with single quotes:
>   - xtty->print_cr("<sect index=%d used=" ...
>   + xtty->print_cr("<sect index='%d' used='" …

Yep.  I'll fix that.

> Perhaps the xml-spewing code should be a method on CodeBuffer itself, so we can log other such bits (stub routines, interpreter, adapters) when we feel like it.

That's a good idea.  I may add a few others if it's easy.


> -- John
> On Nov 3, 2011, at 4:51 PM, Tom Rodriguez wrote:
>> 73 lines changed: 42 ins; 6 del; 25 mod; 14873 unchg
>> 7104960: JSR 292: +VerifyMethodHandles in product JVM can overflow buffer
>> Reviewed-by:
>> The code buffers on limits on sparc didn't properly account for space
>> required then the code cache and were farther apart than an
>> int so it would slightly overflow it's buffer.  It would crash because
>> the CodeCache became corrupted instead of reporting that it
>> overflowed.  I modified the overflow detection logic to work even in
>> product.  It doesn't check on every operation as it does in debug
>> mode, it just vierifies at the end that it hasn't overflowed.  I also
>> extended the ForceUnreachable logic to work on sparc and turned it
>> into a diagnostic so it can be tested in product.  I added logging
>> code to report buffer usage and reset the values on sparc and x86.  If
>> left about 4k of buffer in product mode and 20k in debug mode.

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