[llvm-dev] [proposal] change default ABI for special riscv arch

[Kito Cheng via llvm-dev]

Although GCC didn't implement the implied ABI option,
but I would suggest you create an issue on
riscv-toolchain-conventions[1] and/or raise discussion on RISC-V LLVM
sync up meeting

[1] https://github.com/riscv/riscv-toolchain-conventions

On Tue, Jun 8, 2021 at 4:26 PM Ben Shi via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
>
> I also think the logic of fomulating default arch according to -mabi can be improved.
>
>   // 3. Choose a default based on `-mabi=`
>   //
>   // ilp32e -> rv32e
>   // ilp32 | ilp32f | ilp32d -> rv32imafdc
>   // lp64 | lp64f | lp64d -> rv64imafdc
>
> it can be
>   // ilp32e -> rv32e
>   // ilp32 -> rv32imac
>   // ilp32f -> rv32imacf
>   // ilp32d -> rv32 imacfd
>   // lp64 -> rv64imac
>   // lp64f -> rv64imacf
>   // lp64d -> rv64imacfd
>
>
>
>
>
>
> At 2021-06-08 12:06:15, "Craig Topper" <craig.topper at gmail.com> wrote:
>
> That one line change doesn't look like it handles multiletter extension names correctly. For example, Zbf contains "f".
>
> ~Craig
>
>
> On Mon, Jun 7, 2021 at 8:13 PM Ben Shi via llvm-dev <llvm-dev at lists.llvm.org> wrote:
>>
>> Hello,
>>
>> In the clang's riscv driver,
>> https://github.com/llvm/llvm-project/blob/main/clang/lib/Driver/ToolChains/Arch/RISCV.cpp
>>
>> the default abi is fomulated according to arch if no explicit -mabi is specified.
>>
>> Is it possible to set the default abi to ilp32f for -march=rv32imacf. For my exployer's chip, HW F is used while SW D is used. Each time I have to write "-march=rv32imacf -mabi=ilp32f“， can it be simplified to only "-march=imacf" ? Just adding a line is enough.
>>
>> if (MArch.substr(4).contains_lower("f") && !MArch.substr(4).contains_lower("d"))
>> return "ilp32f";
>>
>> Can I submit a patch to fix it?
>>
>> Ben
>>
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>
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