2023-07-25 13:13:32

by Arnd Bergmann

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

From: Arnd Bergmann <[email protected]>

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/[email protected]/
Signed-off-by: Arnd Bergmann <[email protected]>
---
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

2023-07-28 09:09:40

by Peter Oberparleiter

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

On 25.07.2023 14:23, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> 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/[email protected]/
> Signed-off-by: Arnd Bergmann <[email protected]>

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

Acked-by: Peter Oberparleiter <[email protected]>

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