Re: Re: [PATCH] elfedit: add support for editing e_flags

["Weining Lu" <luweining@loongson.cn>]

LLVM mainline doesn't have such an issue. The output is:
$ clang -c t.c -mabi=lp64s -mfpu=64
warning: triple-implied ABI conflicts with provided target-abi 'lp64s', using target-abi
warning: triple-implied ABI conflicts with provided target-abi 'lp64s', using target-abi
$ readelf -h t.o | grep FLOAT
  Flags:                             0x41, SOFT-FLOAT, OBJ-v1
$ clang -c t.c -mabi=lp64s -mfpu=32
warning: triple-implied ABI conflicts with provided target-abi 'lp64s', using target-abi
warning: triple-implied ABI conflicts with provided target-abi 'lp64s', using target-abi
$ readelf -h t.o | grep FLOAT
  Flags:                             0x41, SOFT-FLOAT, OBJ-v1

> -----原始邮件-----
> 发件人: "Xi Ruoyao" <xry111@xry111.site>
> 发送时间:2023-03-02 19:21:43 (星期四)
> 收件人: "WANG Xuerui" <i.swmail@xen0n.name>, binutils@sourceware.org
> 抄送: "Chenghua Xu" <xuchenghua@loongson.cn>, "Zhensong Liu" <liuzhensong@loongson.cn>, "Qinggang Meng" <mengqinggang@loongson.cn>, "WANG
>  Xuerui" <git@xen0n.name>, "Weining Lu" <luweining@loongson.cn>
> 主题: Re: [PATCH] elfedit: add support for editing e_flags
> 
> On Thu, 2023-03-02 at 19:02 +0800, WANG Xuerui wrote:
> > Indeed the object files are correctly LP64S with FP instructions. Won't 
> > have to ask every LoongArch distro to upgrade toolchains any more...
> 
> You may need to fix and/or upgrade Clang if you want to build the DCN
> driver with it.  A Clang "14.0.6" (no idea what it really is, IIRC even
> Clang 15 does not support LoongArch) on gcc400.fsffrance.org (Arch Linux
> installed) produces:
> 
> [xry111@gcc400 ~]$ clang t.c -c -mabi=lp64s -mfpu=64
> [xry111@gcc400 ~]$ readelf -a a.out | grep FLOAT
>   Flags:                             0x43, DOUBLE-FLOAT, OBJ-v1
> 
> And there is some more strange thing:
> 
> [xry111@gcc400 ~]$ clang t.c -c -mabi=lp64s -mfpu=32
> [xry111@gcc400 ~]$ readelf -a a.out | grep FLOAT
>   Flags:                             0x43, DOUBLE-FLOAT, OBJ-v1
> 
> Why would "lp64s" and "fpu=32" lead to double float ?!
> 
> Cc += Weining, though I'm not sure if this issue still exists in LLVM
> mainline.
> 
> -- 
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University


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