Re: [edk2] [PATCH] ArmPkg/CompilerIntrinsicsLib: fix GCC8 warning for __aeabi_memcpy aliases

[Ard Biesheuvel]

On 7 June 2018 at 07:47, Michael Zimmermann <sigmaepsilo...@gmail.com> wrote:
> This was the warning(shown for __aeabi_memcpy, __aeabi_memcpy4 and 
> __aeabi_memcpy8):
> ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c:42:6: error: '__aeabi_memcpy8' 
> alias between functions of incompatible types 'void(void
> *, const void *, size_t)' {aka 'void(void *, const void *, unsigned int)'} 
> and 'void *(void *, const void *, size_t)' {aka 'void
> *(void *, const void *, unsigned int)'} [-Werror=attribute-alias]
> void __aeabi_memcpy8(void *dest, const void *src, size_t n);
> ^~~~~~~~~~~~~~~
> ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c:19:7: note: aliased declaration 
> here
> void *__memcpy(void *dest, const void *src, size_t n)
>
> The problem is the different return type(void vs void*).
> This commit adds a wrapper '__aeabi___memcpy' with a void return value.
>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Michael Zimmermann <sigmaepsilo...@gmail.com>
> ---
>  ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c 
> b/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c
> index a944e00b89e1..507234186fa9 100644
> --- a/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c
> +++ b/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c
> @@ -31,14 +31,19 @@ __attribute__((__alias__("__memcpy")))
>  void *memcpy(void *dest, const void *src, size_t n);
>
>  #ifdef __arm__
> +static __attribute__((__used__))
> +void __aeabi___memcpy(void *dest, const void *src, size_t n)
> +{
> +  __memcpy(dest, src, n);
> +}
>
> -__attribute__((__alias__("__memcpy")))
> +__attribute__((__alias__("__aeabi___memcpy")))
>  void __aeabi_memcpy(void *dest, const void *src, size_t n);
>
> -__attribute__((__alias__("__memcpy")))
> +__attribute__((__alias__("__aeabi___memcpy")))
>  void __aeabi_memcpy4(void *dest, const void *src, size_t n);
>
> -__attribute__((__alias__("__memcpy")))
> +__attribute__((__alias__("__aeabi___memcpy")))
>  void __aeabi_memcpy8(void *dest, const void *src, size_t n);
>
>  #endif

Thanks Michael.

Would this fix the problem as well?

--- a/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c
+++ b/ArmPkg/Library/CompilerIntrinsicsLib/memcpy.c
@@ -16,20 +16,21 @@
 typedef __SIZE_TYPE__ size_t;

 static __attribute__((__used__))
-void *__memcpy(void *dest, const void *src, size_t n)
+void __memcpy(void *dest, const void *src, size_t n)
 {
   unsigned char *d = dest;
   unsigned char const *s = src;

   while (n--)
     *d++ = *s++;
+}

+void *memcpy(void *dest, const void *src, size_t n)
+{
+  __memcpy(dest, src, n);
   return dest;
 }

-__attribute__((__alias__("__memcpy")))
-void *memcpy(void *dest, const void *src, size_t n);
-
 #ifdef __arm__

 __attribute__((__alias__("__memcpy")))
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