[PATCH v2] Makefile: Fix POSIX grep for multiple patterns

[Anup Patel]

On Fri, Nov 29, 2024 at 3:49 AM Igor Melnikov <imel at purelymail.com> wrote:
>
> grep -e "-mstrict-align\|-mno-unaligned-access" makes use of GNU grep's
> backslash-escaped alternation operator \| which is available in basic
> regular expression syntax (BRE) mode.
>
> However, in POSIX grep's BRE mode | is an ordinary character which, when
> backslash-escaped, matches itself. Therefore, the search pattern becomes
> a plain string '-mstrict-align|-mno-unaligned-access' which obviously
> never matches the expected error and CC_SUPPORT_STRICT_ALIGN is always set
> to y.
>
> When cross-compiling with LLVM on amd64-unknown-openbsd7.6 host for
> riscv64-unknown-elf target this results in a compilation error:
>
> clang: error: unsupported option '-mno-unaligned-access' for target
> 'riscv64-unknown-elf'
>
> Using multiple -e options for this case maintains consistent behaviour
> across different grep implementations and fixes the issue.
>
> Signed-off-by: Igor Melnikov <imel at purelymail.com>

LGTM.

Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup


> ---
>  Makefile | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index dae282c..d9cee49 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -184,10 +184,10 @@ OPENSBI_LD_EXCLUDE_LIBS := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) $(USE_LD_
>  CC_SUPPORT_SAVE_RESTORE := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) -nostdlib -mno-save-restore -x c /dev/null -o /dev/null 2>&1 | grep -e "-save-restore" >/dev/null && echo n || echo y)
>
>  # Check whether the compiler supports -m(no-)strict-align
> -CC_SUPPORT_STRICT_ALIGN := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) -nostdlib -mstrict-align -x c /dev/null -o /dev/null 2>&1 | grep -e "-mstrict-align\|-mno-unaligned-access" >/dev/null && echo n || echo y)
> +CC_SUPPORT_STRICT_ALIGN := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) -nostdlib -mstrict-align -x c /dev/null -o /dev/null 2>&1 | grep -e "-mstrict-align" -e "-mno-unaligned-access" >/dev/null && echo n || echo y)
>
>  # Check whether the assembler and the compiler support the Zicsr and Zifencei extensions
> -CC_SUPPORT_ZICSR_ZIFENCEI := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) -nostdlib -march=rv$(OPENSBI_CC_XLEN)imafd_zicsr_zifencei -x c /dev/null -o /dev/null 2>&1 | grep "zicsr\|zifencei" > /dev/null && echo n || echo y)
> +CC_SUPPORT_ZICSR_ZIFENCEI := $(shell $(CC) $(CLANG_TARGET) $(RELAX_FLAG) -nostdlib -march=rv$(OPENSBI_CC_XLEN)imafd_zicsr_zifencei -x c /dev/null -o /dev/null 2>&1 | grep -e "zicsr" -e "zifencei" > /dev/null && echo n || echo y)
>
>  ifneq ($(OPENSBI_LD_PIE),y)
>  $(error Your linker does not support creating PIEs, opensbi requires this.)
> --
> 2.46.1
>
>
> --
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