[PATCH] ArmPkg/CompilerIntrinsicsLib ARM: make memset() weak again

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

After the recent update of CompilerIntrinsicsLib, our memset() is no
longer emitted as a weak symbol. On ARM, this may cause problems when
combining this library with another library that supplies memset() [e.g.,
CryptoPkg/IntrinsicLib], due to the fact that the object also supplies
the __aeabi_memXXX entry points, which can only be satisfied by this
object. So make our memset() weak again, to let the other implementation
take precedence.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---

This makes ArmVirtQemu build again for ARM with SECURE_BOOT_ENABLE=TRUE

 ArmPkg/Library/CompilerIntrinsicsLib/memset.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/ArmPkg/Library/CompilerIntrinsicsLib/memset.c b/ArmPkg/Library/CompilerIntrinsicsLib/memset.c
index 3d417d797242..0d837fcecf09 100644
--- a/ArmPkg/Library/CompilerIntrinsicsLib/memset.c
+++ b/ArmPkg/Library/CompilerIntrinsicsLib/memset.c
@@ -31,6 +31,15 @@ void *memset(void *dest, int c, size_t n);
 
 #ifdef __arm__
 
+//
+// Other modules (such as CryptoPkg/IntrinsicLib) may provide another
+// implementation of memset(), which may conflict with this one if this
+// object was pulled into the link due to the definitions below. So make
+// our memset() 'weak' to let the other implementation take precedence.
+//
+__attribute__((__weak__))
+void *memset(void *dest, int c, size_t n);
+
 void __aeabi_memset(void *dest, size_t n, int c)
 {
   __memset(dest, c, n);
-- 
2.7.4