gcov: shut up missing prototype warnings for internal stubs

[PATCH] [v2] gcov: shut up missing prototype warnings for internal stubs

Posted by Arnd Bergmann 2 years, 6 months ago

From: Arnd Bergmann <arnd@arndb.de>

gcov uses global functions that are called from generated code,
but these have no prototype in a header, which causes a W=1
build warning:

kernel/gcov/gcc_base.c:12:6: error: no previous prototype for '__gcov_init' [-Werror=missing-prototypes]
kernel/gcov/gcc_base.c:40:6: error: no previous prototype for '__gcov_flush' [-Werror=missing-prototypes]
kernel/gcov/gcc_base.c:46:6: error: no previous prototype for '__gcov_merge_add' [-Werror=missing-prototypes]
kernel/gcov/gcc_base.c:52:6: error: no previous prototype for '__gcov_merge_single' [-Werror=missing-prototypes]

Just turn off these warnings unconditionally for the two files
that contain them.

Link: https://lore.kernel.org/all/0820010f-e9dc-779d-7924-49c7df446bce@linux.ibm.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/gcov/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/gcov/Makefile b/kernel/gcov/Makefile
index 16f8ecc7d8821..ccd02afaeffb4 100644
--- a/kernel/gcov/Makefile
+++ b/kernel/gcov/Makefile
@@ -3,4 +3,6 @@ ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
 
 obj-y := base.o fs.o
 obj-$(CONFIG_CC_IS_GCC) += gcc_base.o gcc_4_7.o
+CFLAGS_gcc_base.o += -Wno-missing-prototypes -Wno-missing-declarations
 obj-$(CONFIG_CC_IS_CLANG) += clang.o
+CFLAGS_clang.o += -Wno-missing-prototypes -Wno-missing-declarations
-- 
2.39.2

Re: [PATCH] [v2] gcov: shut up missing prototype warnings for internal stubs

Posted by Peter Oberparleiter 2 years, 6 months ago

On 25.07.2023 14:23, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> gcov uses global functions that are called from generated code,
> but these have no prototype in a header, which causes a W=1
> build warning:
> 
> kernel/gcov/gcc_base.c:12:6: error: no previous prototype for '__gcov_init' [-Werror=missing-prototypes]
> kernel/gcov/gcc_base.c:40:6: error: no previous prototype for '__gcov_flush' [-Werror=missing-prototypes]
> kernel/gcov/gcc_base.c:46:6: error: no previous prototype for '__gcov_merge_add' [-Werror=missing-prototypes]
> kernel/gcov/gcc_base.c:52:6: error: no previous prototype for '__gcov_merge_single' [-Werror=missing-prototypes]
> 
> Just turn off these warnings unconditionally for the two files
> that contain them.
> 
> Link: https://lore.kernel.org/all/0820010f-e9dc-779d-7924-49c7df446bce@linux.ibm.com/
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Tested successfully with GCC 13.1 and Clang 18. Thanks for the fix!

Acked-by: Peter Oberparleiter <oberpar@linux.ibm.com>

Andrew, could you add this patch via your tree?

> ---
>  kernel/gcov/Makefile | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/gcov/Makefile b/kernel/gcov/Makefile
> index 16f8ecc7d8821..ccd02afaeffb4 100644
> --- a/kernel/gcov/Makefile
> +++ b/kernel/gcov/Makefile
> @@ -3,4 +3,6 @@ ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
>  
>  obj-y := base.o fs.o
>  obj-$(CONFIG_CC_IS_GCC) += gcc_base.o gcc_4_7.o
> +CFLAGS_gcc_base.o += -Wno-missing-prototypes -Wno-missing-declarations
>  obj-$(CONFIG_CC_IS_CLANG) += clang.o
> +CFLAGS_clang.o += -Wno-missing-prototypes -Wno-missing-declarations

-- 
Peter Oberparleiter
Linux on IBM Z Development - IBM Germany R&D