Re: [PATCH v1] MdePkg: Use __builtin_offset with CLANGPDB toolchain

["Liming Gao" <liming.gao@intel.com>]

Alex:
  Do you find the real issue without this fix? Or is this change just an enhancement? 

  As you know, now we are in hard code freeze phase. Only functional bug is allowed. 

Thanks
Liming
>-----Original Message-----
>From: Alex James [mailto:theracermaster@gmail.com]
>Sent: Thursday, November 28, 2019 1:57 PM
>To: devel@edk2.groups.io
>Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Gao, Liming
><liming.gao@intel.com>
>Subject: [PATCH v1] MdePkg: Use __builtin_offset with CLANGPDB toolchain
>
>CLANGPDB does not define __GNUC__, but it does define __clang__. Check
>for the __clang__ preprocessor definition to use __builtin_offsetof to
>implement the OFFSET_OF macro.
>
>Cc: Michael D Kinney <michael.d.kinney@intel.com>
>Cc: Liming Gao <liming.gao@intel.com>
>Signed-off-by: Alex James <theracermaster@gmail.com>
>---
> MdePkg/Include/Base.h | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
>diff --git a/MdePkg/Include/Base.h b/MdePkg/Include/Base.h
>index 4680e64136..e0bcd0ae67 100644
>--- a/MdePkg/Include/Base.h
>+++ b/MdePkg/Include/Base.h
>@@ -781,11 +781,9 @@ typedef UINTN  *BASE_LIST;
>   @return  Offset, in bytes, of field.
>
>
>
> **/
>
>-#ifdef __GNUC__
>
>-#if __GNUC__ >= 4
>
>+#if (defined(__GNUC__) && __GNUC__ >= 4) || defined(__clang__)
>
> #define OFFSET_OF(TYPE, Field) ((UINTN) __builtin_offsetof(TYPE, Field))
>
> #endif
>
>-#endif
>
>
>
> #ifndef OFFSET_OF
>
> #define OFFSET_OF(TYPE, Field) ((UINTN) &(((TYPE *)0)->Field))
>
>--
>2.24.0