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>
Reviewed-by: Liming Gao <liming.gao@intel.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/CryptoPkg/Library/IntrinsicLib/CopyMem.c b/CryptoPkg/Library/IntrinsicLib/CopyMem.c
index e29b4918d2..7faf5a34d8 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__)

+

+/* Copies bytes between buffers */

+static __attribute__((__used__))

+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);

+

+#else

 /* Copies bytes between buffers */

 void * memcpy (void *dest, const void *src, unsigned int count)

 {

   return CopyMem (dest, src, (UINTN)count);

 }

+#endif