review for 7121073: secondary_super_cache memory slice has incorrect bounds in flatten_alias_type
tom.rodriguez at oracle.com
Thu Dec 15 13:02:21 PST 2011
On Dec 15, 2011, at 12:57 PM, Vladimir Kozlov wrote:
> Tom Rodriguez wrote:
>> On Dec 15, 2011, at 12:44 PM, Vladimir Kozlov wrote:
>>> Can you updated related comments? Otherwise looks good.
>> How about this:
>> // If we are referencing a field within a Klass, we need
>> // to assume the worst case of an Object. Both exact and
>> // inexact types must flatten to the same alias class so
>> // use NotNull as the PTR.
>>> Tom Rodriguez wrote:
>>>> 7 lines changed: 2 ins; 0 del; 5 mod; 3239 unchg
>>>> 7121073: secondary_super_cache memory slice has incorrect bounds in flatten_alias_type
>>>> To ensure that memory operations for type checks are properly ordered,
>>>> several fields are smeared together into the same alias slice. The
>>>> existing logic is sloppy and includes a slightly larger chunk of
>>>> memory than intended. Currently this is fine but changes to the shape
>>>> of Klass can invalidate it. The fix is to properly test the
>>>> boundaries. Additionally I changed the logic for setting the PTR to
>>>> use NotNull instead of Constant to be consisten with all the following
>>>> logic which uses NotNull. Tested with full CTW.
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