[PATCH v4 1/2] Makefile: Fix -msave-restore compile warning with CLANG-10 (or lower)

[Anup Patel]

On Fri, Dec 3, 2021 at 6:41 PM Xiang W <wxjstz at 126.com> wrote:
>
> 在 2021-12-03星期五的 10:33 +0530，Anup Patel写道：
> > The riscv target of CLANG-10 (or lower) does not support the
> > -m(no-)save-restore option so we get compile warnings. This patch
> > fixes compile warning by using -m(no-)save-restore option only
> > for GCC.
> >
> > Signed-off-by: Anup Patel <anup.patel at wdc.com>
> > Reviewed-by: Dong Du <Dd_nirvana at sjtu.edu.cn>
> > ---
> >  Makefile | 14 ++++++++++----
> >  1 file changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 8623c1c..d89a0c5 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -275,8 +275,11 @@ GENFLAGS   +=      $(platform-genflags-y)
> >  GENFLAGS       +=      $(firmware-genflags-y)
> >
> >  CFLAGS         =       -g -Wall -Werror -ffreestanding -nostdlib -
> > fno-stack-protector -fno-strict-aliasing -O2
> > -CFLAGS         +=      -fno-omit-frame-pointer -fno-optimize-
> > sibling-calls
> > -CFLAGS         +=      -mno-save-restore -mstrict-align
> > +CFLAGS         +=      -fno-omit-frame-pointer -fno-optimize-
> > sibling-calls -mstrict-align
> > +# CLANG-10 (or lower) does not support -m(no-)save-restore option
> > +ifneq ($(CC_IS_CLANG),y)
> > +CFLAGS         +=      -mno-save-restore
> > +endif
> >  CFLAGS         +=      -mabi=$(PLATFORM_RISCV_ABI) -
> > march=$(PLATFORM_RISCV_ISA)
> >  CFLAGS         +=      -mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
> >  CFLAGS         +=      $(RELAX_FLAG)
> > @@ -290,8 +293,11 @@ CPPFLAGS   +=      $(platform-cppflags-y)
> >  CPPFLAGS       +=      $(firmware-cppflags-y)
> >
> >  ASFLAGS                =       -g -Wall -nostdlib
> > -ASFLAGS                +=      -fno-omit-frame-pointer -fno-
> > optimize-sibling-calls
> > -ASFLAGS                +=      -mno-save-restore -mstrict-align
> > +ASFLAGS                +=      -fno-omit-frame-pointer -fno-
> > optimize-sibling-calls -mstrict-align
> > +# CLANG-10 (or lower) does not support -m(no-)save-restore option
> > +ifneq ($(CC_IS_CLANG),y)
> > +ASFLAGS                +=      -mno-save-restore
> > +endif
> >  ASFLAGS                +=      -mabi=$(PLATFORM_RISCV_ABI) -
> > march=$(PLATFORM_RISCV_ISA)
> >  ASFLAGS                +=      -mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
> >  ASFLAGS                +=      $(RELAX_FLAG)
> > --
> > 2.25.1
> >
> >
>
> Maybe we can dynamically detect whether the toolchain supports
> -m(no-)save-restore, just like we did before to detect whether ld
> supports PIE

Thanks Xiang for this suggestion, I tried it but does not work with GCC.

For now, I will go ahead with v4 patch. You can try it separately and
send incremental patch.

Regards,
Anup

>
> diff --git a/Makefile b/Makefile
> index 8623c1c..4b866ac 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -149,7 +149,7 @@ endif
>
>  # Check whether the linker supports creating PIEs
>  OPENSBI_LD_PIE := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG)
> $(USE_LD_FLAG) -fPIE -nostdlib -Wl,-pie -x c /dev/null -o /dev/null
> >/dev/null 2>&1 && echo y || echo n)
> -
> +CC_SUPPORT_SAVE_RESTORE := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG)
> $(USE_LD_FLAG) -nostdlib -mno-save-restore -x c /dev/null -o /dev/null
> >/dev/null 2>&1 && echo y || echo n)
>  # Build Info:
>  # OPENSBI_BUILD_TIME_STAMP -- the compilation time stamp
>  # OPENSBI_BUILD_COMPILER_VERSION -- the compiler version info
> @@ -275,8 +275,10 @@ GENFLAGS   +=      $(platform-genflags-y)
>  GENFLAGS       +=      $(firmware-genflags-y)
>
>  CFLAGS         =       -g -Wall -Werror -ffreestanding -nostdlib -fno-
> stack-protector -fno-strict-aliasing -O2
> -CFLAGS         +=      -fno-omit-frame-pointer -fno-optimize-sibling-
> calls
> -CFLAGS         +=      -mno-save-restore -mstrict-align
> +CFLAGS         +=      -fno-omit-frame-pointer -fno-optimize-sibling-
> calls -mstrict-align
> +ifeq ($(CC_SUPPORT_SAVE_RESTORE),y)
> +CFLAGS         +=      -mno-save-restore
> +endif
>  CFLAGS         +=      -mabi=$(PLATFORM_RISCV_ABI) -
> march=$(PLATFORM_RISCV_ISA)
>  CFLAGS         +=      -mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
>  CFLAGS         +=      $(RELAX_FLAG)
> @@ -290,8 +292,10 @@ CPPFLAGS   +=      $(platform-cppflags-y)
>  CPPFLAGS       +=      $(firmware-cppflags-y)
>
>  ASFLAGS                =       -g -Wall -nostdlib
> -ASFLAGS                +=      -fno-omit-frame-pointer -fno-optimize-
> sibling-calls
> -ASFLAGS                +=      -mno-save-restore -mstrict-align
> +ASFLAGS                +=      -fno-omit-frame-pointer -fno-optimize-
> sibling-calls -mstrict-align
> +ifeq ($(CC_SUPPORT_SAVE_RESTORE),y)
> +ASFLAGS                +=      -mno-save-restore
> +endif
>  ASFLAGS                +=      -mabi=$(PLATFORM_RISCV_ABI) -
> march=$(PLATFORM_RISCV_ISA)
>  ASFLAGS                +=      -mcmodel=$(PLATFORM_RISCV_CODE_MODEL)
>  ASFLAGS                +=      $(RELAX_FLAG)
>
> Regards,
> Xiang W
>