| Message ID | 20210719205247.1023289-1-twd2.me@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | RISC-V: build: Allow LTO to be selected | expand |
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=$(CONFIG_PAGE_OFFSET) > > -- -- Thanks, ~Nick Desaulniers
Thanks for your advice. After some investigations, I find minimal code that can reproduce the issue I have had. The bug is filed at https://bugs.llvm.org/show_bug.cgi?id=51161. Thanks. Wende On 2021/7/20 5:14, Nick Desaulniers wrote: > On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote: >> Pass `-mattr` to `lld` so that it can generate proper machine code. >> By the way, it seems that `-march` does not work well now. >> >> Signed-off-by: Wende Tan <twd2.me@gmail.com> >> --- >> arch/riscv/Makefile | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile >> index bc74afdbf31e..bbc186a3ab45 100644 >> --- a/arch/riscv/Makefile >> +++ b/arch/riscv/Makefile >> @@ -52,9 +52,16 @@ riscv-march-$(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=$(CONFIG_PAGE_OFFSET) >> >> -- > > -- > Thanks, > ~Nick Desaulniers
On Thu, Jul 22, 2021 at 1:23 AM twd2 <twd2.me@gmail.com> wrote: > > Thanks for your advice. After some investigations, I find minimal code > that can reproduce the issue I have had. The bug is filed at > https://bugs.llvm.org/show_bug.cgi?id=51161. Perfect! Thank you for filing that. Let's get that fixed up, then revisit LTO for RISCV.
On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote: > On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote: >> >> Pass `-mattr` to `lld` so that it can generate proper machine code. >> By the way, it seems that `-march` does not work well now. >> >> Signed-off-by: Wende Tan <twd2.me@gmail.com> >> --- >> arch/riscv/Makefile | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile >> index bc74afdbf31e..bbc186a3ab45 100644 >> --- a/arch/riscv/Makefile >> +++ b/arch/riscv/Makefile >> @@ -52,9 +52,16 @@ riscv-march-$(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=$(CONFIG_PAGE_OFFSET) >> >> --
Sure. I'll send a v2 after the LLVM issue is resolved. Thanks! Wende On 2021/8/5 4:59, Palmer Dabbelt wrote: > On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote: >> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote: >>> >>> Pass `-mattr` to `lld` so that it can generate proper machine code. >>> By the way, it seems that `-march` does not work well now. >>> >>> Signed-off-by: Wende Tan <twd2.me@gmail.com> >>> --- >>> arch/riscv/Makefile | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile >>> index bc74afdbf31e..bbc186a3ab45 100644 >>> --- a/arch/riscv/Makefile >>> +++ b/arch/riscv/Makefile >>> @@ -52,9 +52,16 @@ riscv-march-$(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=$(CONFIG_PAGE_OFFSET) >>> >>> --
On Thu, Aug 5, 2021 at 1:12 PM twd2 <twd2.me@gmail.com> wrote: > > Sure. I'll send a v2 after the LLVM issue is resolved. > > Thanks! > Wende > > > On 2021/8/5 4:59, Palmer Dabbelt wrote: > > On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote: > >> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote: > >>> > >>> Pass `-mattr` to `lld` so that it can generate proper machine code. > >>> By the way, it seems that `-march` does not work well now. > >>> > >>> Signed-off-by: Wende Tan <twd2.me@gmail.com> > >>> --- > >>> arch/riscv/Makefile | 7 +++++++ > >>> 1 file changed, 7 insertions(+) > >>> > >>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile > >>> index bc74afdbf31e..bbc186a3ab45 100644 > >>> --- a/arch/riscv/Makefile > >>> +++ b/arch/riscv/Makefile > >>> @@ -52,9 +52,16 @@ riscv-march-$(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=$(CONFIG_PAGE_OFFSET) > >>> > >>> -- > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/a6615b69-d99f-220b-d980-1f5f40ee2999%40gmail.com.
Hi, I think we even don't need this option after the issue I filed is fixed. Thanks! Wende On 2021/8/6 4:18, Fāng-ruì Sòng wrote: > On Thu, Aug 5, 2021 at 1:12 PM twd2 <twd2.me@gmail.com> wrote: >> Sure. I'll send a v2 after the LLVM issue is resolved. >> >> Thanks! >> Wende >> >> >> On 2021/8/5 4:59, Palmer Dabbelt wrote: >>> On Mon, 19 Jul 2021 14:14:59 PDT (-0700), ndesaulniers@google.com wrote: >>>> On Mon, Jul 19, 2021 at 1:53 PM Wende Tan <twd2.me@gmail.com> wrote: >>>>> Pass `-mattr` to `lld` so that it can generate proper machine code. >>>>> By the way, it seems that `-march` does not work well now. >>>>> >>>>> Signed-off-by: Wende Tan <twd2.me@gmail.com> >>>>> --- >>>>> arch/riscv/Makefile | 7 +++++++ >>>>> 1 file changed, 7 insertions(+) >>>>> >>>>> diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile >>>>> index bc74afdbf31e..bbc186a3ab45 100644 >>>>> --- a/arch/riscv/Makefile >>>>> +++ b/arch/riscv/Makefile >>>>> @@ -52,9 +52,16 @@ riscv-march-$(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=$(CONFIG_PAGE_OFFSET) >>>>> >>>>> -- >> -- >> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. >> To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@googlegroups.com. >> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/a6615b69-d99f-220b-d980-1f5f40ee2999%40gmail.com. >
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile index bc74afdbf31e..bbc186a3ab45 100644 --- a/arch/riscv/Makefile +++ b/arch/riscv/Makefile @@ -52,9 +52,16 @@ riscv-march-$(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)
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(+)