Re: [edk2-devel] [PATCH v1 1/1] CryptoPkg/IntrinsicLib: Fix CLANG38 IA32 build problem

["Xiaoyu Lu" <xiaoyux.lu@intel.com>]

Liming,

> -----Original Message-----
> From: Gao, Liming
> Sent: Wednesday, June 5, 2019 3:28 PM
> To: Lu, XiaoyuX <xiaoyux.lu@intel.com>; devel@edk2.groups.io
> Cc: Bi, Dandan <dandan.bi@intel.com>; Wang, Jian J <jian.j.wang@intel.com>
> Subject: RE: [edk2-devel] [PATCH v1 1/1] CryptoPkg/IntrinsicLib: Fix
> CLANG38 IA32 build problem
> 
> Xiaoyu:
> 
> > -----Original Message-----
> > From: Lu, XiaoyuX
> > Sent: Wednesday, June 5, 2019 2:34 PM
> > To: Gao, Liming <liming.gao@intel.com>; devel@edk2.groups.io
> > Cc: Bi, Dandan <dandan.bi@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>
> > Subject: RE: [edk2-devel] [PATCH v1 1/1] CryptoPkg/IntrinsicLib: Fix
> CLANG38 IA32 build problem
> >
> > Hi Liming,
> >
> > > -----Original Message-----
> > > From: Gao, Liming
> > > Sent: Wednesday, June 5, 2019 1:57 PM
> > > To: devel@edk2.groups.io; Lu, XiaoyuX <xiaoyux.lu@intel.com>
> > > Cc: Bi, Dandan <dandan.bi@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>
> > > Subject: RE: [edk2-devel] [PATCH v1 1/1] CryptoPkg/IntrinsicLib: Fix
> > > CLANG38 IA32 build problem
> > >
> > > Xiaoyu:
> > >
> > > >-----Original Message-----
> > > >From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf
> Of
> > > >Xiaoyu Lu
> > > >Sent: Wednesday, June 05, 2019 1:25 PM
> > > >To: devel@edk2.groups.io
> > > >Cc: Lu, XiaoyuX <xiaoyux.lu@intel.com>; Bi, Dandan
> > > <dandan.bi@intel.com>;
> > > >Wang, Jian J <jian.j.wang@intel.com>
> > > >Subject: [edk2-devel] [PATCH v1 1/1] CryptoPkg/IntrinsicLib: Fix
> CLANG38
> > > >IA32 build problem
> > > >
> > > >When use clang-3.8 to build the NetworkPkg, compiler optimization
> > > >may use memcpy for memory copy. For example:
> > > >
> > > > CryptoPkg/Library/OpensslLib/openssl/ssl/ssl_rsa.c:918: undefined
> > > > reference to `memcpy'`
> > > >
> > > >Compiler optimization is sophisticated, but we can work around it
> > > >use __attribute__((__used__)) to informs the compiler that symbol
> > > >should be retained in the object file, even if it may be
> > > >unreferenced.
> > > >
> > > >Cc: Jian J Wang <jian.j.wang@intel.com>
> > > >Cc: Dandan Bi <dandan.bi@intel.com>
> > > >Signed-off-by: Xiaoyu Lu <xiaoyux.lu@intel.com>
> > > >---
> > > > CryptoPkg/Library/IntrinsicLib/CopyMem.c | 13 +++++++++++++
> > > > 1 file changed, 13 insertions(+)
> > > >
> > > >diff --git a/CryptoPkg/Library/IntrinsicLib/CopyMem.c
> > > >b/CryptoPkg/Library/IntrinsicLib/CopyMem.c
> > > >index e29b4918d200..7faf5a34d8c1 100644
> > > >--- a/CryptoPkg/Library/IntrinsicLib/CopyMem.c
> > > >+++ b/CryptoPkg/Library/IntrinsicLib/CopyMem.c
> > > >@@ -10,8 +10,21 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > > > #include <Base.h>
> > > > #include <Library/BaseMemoryLib.h>
> > > >
> > > >+#if defined(__clang__) && !defined(__APPLE__)
> > >
> > > So, this change is only for CLANG tool chain.
> > >
> > > >+
> > > >+/* Copies bytes between buffers */
> > > >+static __attribute__((__used__))
> > >
> > > What purpose for static?
> > >
> >
> > Because I want __memcpy only use in this file scope.
> >
> > > >+void * __memcpy (void *dest, const void *src, unsigned int count)
> > > >+{
> > > >+  return CopyMem (dest, src, (UINTN)count);
> > > >+}
> > > >+__attribute__((__alias__("__memcpy")))
> > > >+void * memcpy (void *dest, const void *src, unsigned int count);
> > >
> > > __memcpy is IA32 Intrinsic API, memcpy is X64 Intrinsic API, right?
> > >
> >
> > __memcpy isn't IA32 Intrinsic API, only memcpy is intrinsic API for both
> IA32 and X64.
> >
> > The reason I alias memcpy and use __attribute__((__used__)) is let
> compiler retain symbol in object file,
> > So it can link correct.
> >
> > Is this correct?
> >
> 
> Make sense. What test have been done by you? Build pass and Boot pass?
> 

Build pass and BaseCryptLib functions test pass.
I don't test http boot.

Thanks,
Xiaoyu

> > > Thanks
> > > Liming
> >
> > > >+
> > > >+#else
> > > > /* Copies bytes between buffers */
> > > > void * memcpy (void *dest, const void *src, unsigned int count)
> > > > {
> > > >   return CopyMem (dest, src, (UINTN)count);
> > > > }
> > > >+#endif
> > > >--
> > > >2.7.4
> > > >
> > > >
> > > >