* [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
@ 2021-07-19 20:52 Wende Tan
2021-07-19 21:14 ` Nick Desaulniers
0 siblings, 1 reply; 8+ messages in thread
From: Wende Tan @ 2021-07-19 20:52 UTC (permalink / raw)
To: palmer, paul.walmsley, aou, linux-riscv; +Cc: Wende Tan, clang-built-linux
Pass `-mattr` to `lld` so that it can generate proper machine code.
By the way, it seems that `-march` does not work well now.
Signed-off-by: Wende Tan <twd2.me@gmail.com>
---
arch/riscv/Makefile | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index bc74afdbf31e..bbc186a3ab45 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
+riscv-mattr-y := +m,+a
+riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
+riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
KBUILD_AFLAGS += -march=$(riscv-march-y)
+ifeq ($(CONFIG_LD_IS_LLD),y)
+ KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
+endif
+
KBUILD_CFLAGS += -mno-save-restore
KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
--
2.25.1
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^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-07-19 20:52 [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld` Wende Tan
@ 2021-07-19 21:14 ` Nick Desaulniers
2021-07-22 8:23 ` twd2
2021-08-04 20:59 ` Palmer Dabbelt
0 siblings, 2 replies; 8+ messages in thread
From: Nick Desaulniers @ 2021-07-19 21:14 UTC (permalink / raw)
To: Wende Tan
Cc: palmer, paul.walmsley, aou, linux-riscv, clang-built-linux,
Masahiro Yamada, Kees Cook
On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
>
> Pass `-mattr` to `lld` so that it can generate proper machine code.
> By the way, it seems that `-march` does not work well now.
>
> Signed-off-by: Wende Tan <twd2.me@gmail.com>
> ---
> arch/riscv/Makefile | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> index bc74afdbf31e..bbc186a3ab45 100644
> --- a/arch/riscv/Makefile
> +++ b/arch/riscv/Makefile
> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
> +riscv-mattr-y := +m,+a
> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
> KBUILD_AFLAGS += -march=$(riscv-march-y)
>
> +ifeq ($(CONFIG_LD_IS_LLD),y)
> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
We should prevent the proliferation of the compiler internal `-mllvm`
flags from Kbuild Makefiles; these are indicative of LLVM IR specific
issues with regards to LTO. Can you please file a bug against LLVM
that `-mattr` should be encoded in the IR for LTO's sake?
See also:
commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
< 13.0.0")
commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
> +endif
> +
> KBUILD_CFLAGS += -mno-save-restore
> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
>
> --
--
Thanks,
~Nick Desaulniers
_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-07-19 21:14 ` Nick Desaulniers
@ 2021-07-22 8:23 ` twd2
2021-07-27 20:22 ` Nick Desaulniers
2021-08-04 20:59 ` Palmer Dabbelt
1 sibling, 1 reply; 8+ messages in thread
From: twd2 @ 2021-07-22 8:23 UTC (permalink / raw)
To: Nick Desaulniers
Cc: palmer, paul.walmsley, aou, linux-riscv, clang-built-linux,
Masahiro Yamada, Kees Cook
Thanks for your advice. After some investigations, I find minimal code
that can reproduce the issue I have had. The bug is filed at
https://bugs.llvm.org/show_bug.cgi?id=51161.
Thanks.
Wende
On 2021/7/20 5:14, Nick Desaulniers wrote:
> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
>> Pass `-mattr` to `lld` so that it can generate proper machine code.
>> By the way, it seems that `-march` does not work well now.
>>
>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
>> ---
>> arch/riscv/Makefile | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
>> index bc74afdbf31e..bbc186a3ab45 100644
>> --- a/arch/riscv/Makefile
>> +++ b/arch/riscv/Makefile
>> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
>> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
>> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
>> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
>> +riscv-mattr-y := +m,+a
>> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
>> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
>> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
>> KBUILD_AFLAGS += -march=$(riscv-march-y)
>>
>> +ifeq ($(CONFIG_LD_IS_LLD),y)
>> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
> We should prevent the proliferation of the compiler internal `-mllvm`
> flags from Kbuild Makefiles; these are indicative of LLVM IR specific
> issues with regards to LTO. Can you please file a bug against LLVM
> that `-mattr` should be encoded in the IR for LTO's sake?
>
> See also:
> commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
> < 13.0.0")
> commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
>
>> +endif
>> +
>> KBUILD_CFLAGS += -mno-save-restore
>> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
>>
>> --
>
> --
> Thanks,
> ~Nick Desaulniers
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-07-22 8:23 ` twd2
@ 2021-07-27 20:22 ` Nick Desaulniers
0 siblings, 0 replies; 8+ messages in thread
From: Nick Desaulniers @ 2021-07-27 20:22 UTC (permalink / raw)
To: twd2
Cc: palmer, paul.walmsley, aou, linux-riscv, clang-built-linux,
Masahiro Yamada, Kees Cook
On Thu, Jul 22, 2021 at 1:23 AM twd2 <twd2.me@gmail.com> wrote:
>
> Thanks for your advice. After some investigations, I find minimal code
> that can reproduce the issue I have had. The bug is filed at
> https://bugs.llvm.org/show_bug.cgi?id=51161.
Perfect! Thank you for filing that. Let's get that fixed up, then
revisit LTO for RISCV.
--
Thanks,
~Nick Desaulniers
_______________________________________________
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linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-07-19 21:14 ` Nick Desaulniers
2021-07-22 8:23 ` twd2
@ 2021-08-04 20:59 ` Palmer Dabbelt
2021-08-05 20:12 ` twd2
1 sibling, 1 reply; 8+ messages in thread
From: Palmer Dabbelt @ 2021-08-04 20:59 UTC (permalink / raw)
To: ndesaulniers
Cc: twd2.me, Paul Walmsley, aou, linux-riscv, clang-built-linux,
masahiroy, keescook
On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote:
> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
>>
>> Pass `-mattr` to `lld` so that it can generate proper machine code.
>> By the way, it seems that `-march` does not work well now.
>>
>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
>> ---
>> arch/riscv/Makefile | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
>> index bc74afdbf31e..bbc186a3ab45 100644
>> --- a/arch/riscv/Makefile
>> +++ b/arch/riscv/Makefile
>> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
>> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
>> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
>> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
>> +riscv-mattr-y := +m,+a
>> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
>> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
>> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
>> KBUILD_AFLAGS += -march=$(riscv-march-y)
>>
>> +ifeq ($(CONFIG_LD_IS_LLD),y)
>> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
>
> We should prevent the proliferation of the compiler internal `-mllvm`
> flags from Kbuild Makefiles; these are indicative of LLVM IR specific
> issues with regards to LTO. Can you please file a bug against LLVM
> that `-mattr` should be encoded in the IR for LTO's sake?
Works for me. I'll hold off on taking this until the LLVM bug gets
sorted out and expect a v2 (ideally with the other textual changes Nick
suggested).
Thanks!
>
> See also:
> commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
> < 13.0.0")
> commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
>
>> +endif
>> +
>> KBUILD_CFLAGS += -mno-save-restore
>> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
>>
>> --
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-08-04 20:59 ` Palmer Dabbelt
@ 2021-08-05 20:12 ` twd2
2021-08-05 20:18 ` Fāng-ruì Sòng
0 siblings, 1 reply; 8+ messages in thread
From: twd2 @ 2021-08-05 20:12 UTC (permalink / raw)
To: Palmer Dabbelt
Cc: Paul Walmsley, aou, linux-riscv, clang-built-linux, masahiroy,
keescook, Nick Desaulniers
Sure. I'll send a v2 after the LLVM issue is resolved.
Thanks!
Wende
On 2021/8/5 4:59, Palmer Dabbelt wrote:
> On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote:
>> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
>>>
>>> Pass `-mattr` to `lld` so that it can generate proper machine code.
>>> By the way, it seems that `-march` does not work well now.
>>>
>>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
>>> ---
>>> arch/riscv/Makefile | 7 +++++++
>>> 1 file changed, 7 insertions(+)
>>>
>>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
>>> index bc74afdbf31e..bbc186a3ab45 100644
>>> --- a/arch/riscv/Makefile
>>> +++ b/arch/riscv/Makefile
>>> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
>>> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
>>> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
>>> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
>>> +riscv-mattr-y := +m,+a
>>> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
>>> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
>>> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
>>> KBUILD_AFLAGS += -march=$(riscv-march-y)
>>>
>>> +ifeq ($(CONFIG_LD_IS_LLD),y)
>>> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
>>
>> We should prevent the proliferation of the compiler internal `-mllvm`
>> flags from Kbuild Makefiles; these are indicative of LLVM IR specific
>> issues with regards to LTO. Can you please file a bug against LLVM
>> that `-mattr` should be encoded in the IR for LTO's sake?
>
> Works for me. I'll hold off on taking this until the LLVM bug gets sorted out and expect a v2 (ideally with the other textual changes Nick suggested).
>
> Thanks!
>
>>
>> See also:
>> commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
>> < 13.0.0")
>> commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
>>
>>> +endif
>>> +
>>> KBUILD_CFLAGS += -mno-save-restore
>>> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
>>>
>>> --
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http://lists.infradead.org/mailman/listinfo/linux-riscv
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-08-05 20:12 ` twd2
@ 2021-08-05 20:18 ` Fāng-ruì Sòng
2021-08-05 21:05 ` twd2
0 siblings, 1 reply; 8+ messages in thread
From: Fāng-ruì Sòng @ 2021-08-05 20:18 UTC (permalink / raw)
To: twd2
Cc: Palmer Dabbelt, Paul Walmsley, aou, linux-riscv,
clang-built-linux, masahiroy, keescook, Nick Desaulniers
On Thu, Aug 5, 2021 at 1:12 PM twd2 <twd2.me@gmail.com> wrote:
>
> Sure. I'll send a v2 after the LLVM issue is resolved.
>
> Thanks!
> Wende
>
>
> On 2021/8/5 4:59, Palmer Dabbelt wrote:
> > On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote:
> >> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
> >>>
> >>> Pass `-mattr` to `lld` so that it can generate proper machine code.
> >>> By the way, it seems that `-march` does not work well now.
> >>>
> >>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
> >>> ---
> >>> arch/riscv/Makefile | 7 +++++++
> >>> 1 file changed, 7 insertions(+)
> >>>
> >>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
> >>> index bc74afdbf31e..bbc186a3ab45 100644
> >>> --- a/arch/riscv/Makefile
> >>> +++ b/arch/riscv/Makefile
> >>> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
> >>> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
> >>> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
> >>> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
> >>> +riscv-mattr-y := +m,+a
> >>> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
> >>> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
> >>> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
> >>> KBUILD_AFLAGS += -march=$(riscv-march-y)
> >>>
> >>> +ifeq ($(CONFIG_LD_IS_LLD),y)
> >>> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
> >>
> >> We should prevent the proliferation of the compiler internal `-mllvm`
> >> flags from Kbuild Makefiles; these are indicative of LLVM IR specific
> >> issues with regards to LTO. Can you please file a bug against LLVM
> >> that `-mattr` should be encoded in the IR for LTO's sake?
> >
> > Works for me. I'll hold off on taking this until the LLVM bug gets sorted out and expect a v2 (ideally with the other textual changes Nick suggested).
> >
> > Thanks!
For GNU ld compatibility: -mllvm -mattr=xxx => -plugin-opt=-mattr=xxx
Which can allow us to drop the CONFIG_LD_IS_LLD condition.
(gold doesn't support RISC-V yet.)
Note: LLVM LTO + GNU ld support is experimental and has very little testing.
To actually make GNU ld work, we probably also need to teach GNU nm
and ar to specify --plugin LLVMgold.so
https://llvm.org/docs/GoldPlugin.html
> >>
> >> See also:
> >> commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
> >> < 13.0.0")
> >> commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
> >>
> >>> +endif
> >>> +
> >>> KBUILD_CFLAGS += -mno-save-restore
> >>> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
> >>>
> >>> --
>
> --
> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/a6615b69-d99f-220b-d980-1f5f40ee2999%40gmail.com.
--
宋方睿
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^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld`
2021-08-05 20:18 ` Fāng-ruì Sòng
@ 2021-08-05 21:05 ` twd2
0 siblings, 0 replies; 8+ messages in thread
From: twd2 @ 2021-08-05 21:05 UTC (permalink / raw)
To: Fāng-ruì Sòng
Cc: Palmer Dabbelt, Paul Walmsley, aou, linux-riscv,
clang-built-linux, masahiroy, keescook, Nick Desaulniers
Hi,
I think we even don't need this option after the issue I filed is fixed.
Thanks!
Wende
On 2021/8/6 4:18, Fāng-ruì Sòng wrote:
> On Thu, Aug 5, 2021 at 1:12 PM twd2 <twd2.me@gmail.com> wrote:
>> Sure. I'll send a v2 after the LLVM issue is resolved.
>>
>> Thanks!
>> Wende
>>
>>
>> On 2021/8/5 4:59, Palmer Dabbelt wrote:
>>> On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote:
>>>> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote:
>>>>> Pass `-mattr` to `lld` so that it can generate proper machine code.
>>>>> By the way, it seems that `-march` does not work well now.
>>>>>
>>>>> Signed-off-by: Wende Tan <twd2.me@gmail.com>
>>>>> ---
>>>>> arch/riscv/Makefile | 7 +++++++
>>>>> 1 file changed, 7 insertions(+)
>>>>>
>>>>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
>>>>> index bc74afdbf31e..bbc186a3ab45 100644
>>>>> --- a/arch/riscv/Makefile
>>>>> +++ b/arch/riscv/Makefile
>>>>> @@ -52,9 +52,16 @@ riscv-march-$(CONFIG_ARCH_RV32I) := rv32ima
>>>>> riscv-march-$(CONFIG_ARCH_RV64I) := rv64ima
>>>>> riscv-march-$(CONFIG_FPU) := $(riscv-march-y)fd
>>>>> riscv-march-$(CONFIG_RISCV_ISA_C) := $(riscv-march-y)c
>>>>> +riscv-mattr-y := +m,+a
>>>>> +riscv-mattr-$(CONFIG_FPU) := $(riscv-mattr-y),+f,+d
>>>>> +riscv-mattr-$(CONFIG_RISCV_ISA_C) := $(riscv-mattr-y),+c
>>>>> KBUILD_CFLAGS += -march=$(subst fd,,$(riscv-march-y))
>>>>> KBUILD_AFLAGS += -march=$(riscv-march-y)
>>>>>
>>>>> +ifeq ($(CONFIG_LD_IS_LLD),y)
>>>>> + KBUILD_LDFLAGS += -mllvm -mattr=$(riscv-mattr-y)
>>>> We should prevent the proliferation of the compiler internal `-mllvm`
>>>> flags from Kbuild Makefiles; these are indicative of LLVM IR specific
>>>> issues with regards to LTO. Can you please file a bug against LLVM
>>>> that `-mattr` should be encoded in the IR for LTO's sake?
>>> Works for me. I'll hold off on taking this until the LLVM bug gets sorted out and expect a v2 (ideally with the other textual changes Nick suggested).
>>>
>>> Thanks!
> For GNU ld compatibility: -mllvm -mattr=xxx => -plugin-opt=-mattr=xxx
>
> Which can allow us to drop the CONFIG_LD_IS_LLD condition.
> (gold doesn't support RISC-V yet.)
>
> Note: LLVM LTO + GNU ld support is experimental and has very little testing.
> To actually make GNU ld work, we probably also need to teach GNU nm
> and ar to specify --plugin LLVMgold.so
> https://llvm.org/docs/GoldPlugin.html
>
>
>>>> See also:
>>>> commit 0236526d76b8 ("Makefile: lto: Pass -warn-stack-size only on LLD
>>>> < 13.0.0")
>>>> commit 2398ce80152a ("x86, lto: Pass -stack-alignment only on LLD < 13.0.0")
>>>>
>>>>> +endif
>>>>> +
>>>>> KBUILD_CFLAGS += -mno-save-restore
>>>>> KBUILD_CFLAGS += -DCONFIG_PAGE_OFFSET=$(CONFIG_PAGE_OFFSET)
>>>>>
>>>>> --
>> --
>> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com.
>> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/a6615b69-d99f-220b-d980-1f5f40ee2999%40gmail.com.
>
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2021-07-19 20:52 [PATCH 1/3] RISC-V: build: Pass `-mattr` to `lld` Wende Tan
2021-07-19 21:14 ` Nick Desaulniers
2021-07-22 8:23 ` twd2
2021-07-27 20:22 ` Nick Desaulniers
2021-08-04 20:59 ` Palmer Dabbelt
2021-08-05 20:12 ` twd2
2021-08-05 20:18 ` Fāng-ruì Sòng
2021-08-05 21:05 ` twd2
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