Re: [PATCH 1/1] MdePkg/Base.h: Implement BASE_CR() via OFFSET_OF().

[Andrew Fish <afish@apple.com>]

+1

Reviewed-by: Andrew Fish <afish@apple.com>

> On Nov 2, 2018, at 10:28 AM, Kinney, Michael D <michael.d.kinney@intel.com> wrote:
> 
> Marvin,
> 
> Thanks.  This is a good improvement.
> 
> Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
> 
> Mike
> 
>> -----Original Message-----
>> From: Gao, Liming
>> Sent: Thursday, November 1, 2018 6:33 PM
>> To: Marvin.Haeuser@outlook.com; edk2-devel@lists.01.org
>> Cc: Kinney, Michael D <michael.d.kinney@intel.com>
>> Subject: RE: [PATCH 1/1] MdePkg/Base.h: Implement
>> BASE_CR() via OFFSET_OF().
>> 
>> The change is good. Reviewed-by: Liming Gao
>> <liming.gao@intel.com>
>> 
>>> -----Original Message-----
>>> From: edk2-devel [mailto:edk2-devel-
>> bounces@lists.01.org] On Behalf Of
>>> Marvin H?user
>>> Sent: Thursday, November 01, 2018 4:09 AM
>>> To: edk2-devel@lists.01.org
>>> Cc: Kinney, Michael D <michael.d.kinney@intel.com>;
>> Gao, Liming
>>> <liming.gao@intel.com>
>>> Subject: [edk2] [PATCH 1/1] MdePkg/Base.h: Implement
>> BASE_CR() via
>>> OFFSET_OF().
>>> 
>>> Replace the current NULL pointer dereference to
>> retrieve Field's
>>> offset with a call to OFFSET_OF().  This is implemented
>> via
>>> __builtin_offsetof for GCC and Clang, which eliminates
>> UB caught by
>>> Clang UndefinedBehaviorSanitizer.
>>> 
>>> Contributed-under: TianoCore Contribution Agreement 1.1
>>> Signed-off-by: Marvin Haeuser
>> <Marvin.Haeuser@outlook.com>
>>> ---
>>> MdePkg/Include/Base.h | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>> 
>>> diff --git a/MdePkg/Include/Base.h
>> b/MdePkg/Include/Base.h
>>> index 523192fd79fc..bc877d8125a5 100644
>>> --- a/MdePkg/Include/Base.h
>>> +++ b/MdePkg/Include/Base.h
>>> @@ -869,7 +869,7 @@ typedef UINTN  *BASE_LIST;
>>>  @return  A pointer to the structure from one of it's
>> elements.
>>> 
>>> **/
>>> -#define BASE_CR(Record, TYPE, Field)  ((TYPE *)
>> ((CHAR8 *) (Record) -
>>> (CHAR8 *) &(((TYPE *) 0)->Field)))
>>> +#define BASE_CR(Record, TYPE, Field)  ((TYPE *)
>> ((CHAR8 *) (Record) -
>>> OFFSET_OF (TYPE, Field)))
>>> 
>>> /**
>>>  Rounds a value up to the next boundary using a
>> specified alignment.
>>> --
>>> 2.19.1.windows.1
>>> 
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