[PATCH] RISC-V: Add an implicit dependency for Zawrs

[Xiao Zeng]

2024-10-08 14:31  Andrew Waterman <andrew@sifive.com> wrote:
>
>On Mon, Oct 7, 2024 at 11:29 PM Xiao Zeng <zengxiao@eswincomputing.com> wrote:
>>
>> 2024-10-08 14:18  Andrew Waterman <andrew@sifive.com> wrote:
>> >
>> >But that's not what the normative text in the spec says!
>> Yes.
>> > Using non-normative notes to infer dependencies between extensions is
>> >dangerous territory.
>> >
>> >It is true that the WRS instructions aren't useful without the LR
>> >instruction,
>> Perhaps the spec should specify more clearly:
>> "Implicit dependencies should not be inferred from any direct explanation"
>>
>> >but it is also true that Binutils shouldn't be inventing
>> >extension dependencies that aren't normatively justified.
>> Yes, thank you for your suggestion.
>>
>> I will wait for the spec to clarify this.
>
>Non-normative text is, well, not normative.  No clarification in the
>spec is needed. 
Thank you for Andrew's response. It has provided me with a clearer understanding
of the spec. I will continue to follow and monitor its progress.

>
>> >
>> >
>> >On Mon, Oct 7, 2024 at 11:07 PM Xiao Zeng <zengxiao@eswincomputing.com> wrote:
>> >>
>> >> There is a description in <https://github.com/riscv/riscv-isa-manual/blob/main/src/zawrs.adoc>:
>> >>
>> >> "The instructions in the Zawrs extension are only useful in conjunction
>> >> with the LR instruction, which is provided by the Zalrsc component
>> >> of the A extension."
>> >>
>> >> It can be concluded that: zawrs -> zalrsc.
>> >>
>> >> The implementation in gcc is as follows:
>> >> <https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=c01e3aaae79ecd439ad35063db3dee9775f3aefa>
>> >>
>> >> bfd/ChangeLog:
>> >>
>> >>         * elfxx-riscv.c: zawrs -> zalrsc.
>> >>
>> >> gas/ChangeLog:
>> >>
>> >>         * testsuite/gas/riscv/imply.d: Add implicit dependency
>> >>         testing for zawrs.
>> >>         * testsuite/gas/riscv/imply.s: Updated.
>> >>
>> >> Signed-off-by: Xiao Zeng <zengxiao@eswincomputing.com>
>> >> ---
>> >>  bfd/elfxx-riscv.c               | 1 +
>> >>  gas/testsuite/gas/riscv/imply.d | 1 +
>> >>  gas/testsuite/gas/riscv/imply.s | 1 +
>> >>  3 files changed, 3 insertions(+)
>> >>
>> >> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
>> >> index 4b48d8ee9f0..b7b4d95195e 100644
>> >> --- a/bfd/elfxx-riscv.c
>> >> +++ b/bfd/elfxx-riscv.c
>> >> @@ -1184,6 +1184,7 @@ static struct riscv_implicit_subset riscv_implicit_subsets[] =
>> >>
>> >>    {"zabha", "+zaamo", check_implicit_always},
>> >>    {"zacas", "+zaamo", check_implicit_always},
>> >> +  {"zawrs", "+zalrsc", check_implicit_always},
>> >>    {"a", "+zaamo,+zalrsc", check_implicit_always},
>> >>
>> >>    {"xsfvcp", "+zve32x", check_implicit_always},
>> >> diff --git a/gas/testsuite/gas/riscv/imply.d b/gas/testsuite/gas/riscv/imply.d
>> >> index 26eff8c650a..64dda77a9f8 100644
>> >> --- a/gas/testsuite/gas/riscv/imply.d
>> >> +++ b/gas/testsuite/gas/riscv/imply.d
>> >> @@ -17,6 +17,7 @@ SYMBOL TABLE:
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_m2p0_zmmul1p0
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_zaamo1p0_zabha1p0
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_zaamo1p0_zacas1p0
>> >> +[0-9a-f]+ l       .text        0+000 \$xrv32i2p1_zalrsc1p0_zawrs1p0
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_a2p1_zaamo1p0_zalrsc1p0
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_zicsr2p0_zve32x1p0_zvl32b1p0_xsfvcp1p0
>> >>  [0-9a-f]+ l       .text        0+000 \$xrv32i2p1_f2p2_d2p2_v1p0_zicsr2p0_zve32f1p0_zve32x1p0_zve64d1p0_zve64f1p0_zve64x1p0_zvl128b1p0_zvl32b1p0_zvl64b1p0
>> >> diff --git a/gas/testsuite/gas/riscv/imply.s b/gas/testsuite/gas/riscv/imply.s
>> >> index dabb08d8c8b..c831ea63f04 100644
>> >> --- a/gas/testsuite/gas/riscv/imply.s
>> >> +++ b/gas/testsuite/gas/riscv/imply.s
>> >> @@ -18,6 +18,7 @@ imply m
>> >>
>> >>  imply zabha
>> >>  imply zacas
>> >> +imply zawrs
>> >>  imply a
>> >>
>> >>  imply xsfvcp
>> >> --
>> >> 2.17.1
>> >>
>> Thanks
>> Xiao Zeng
>>
Thanks
Xiao Zeng