From: Nathan Chancellor <nathan@kernel.org> To: Kalle Valo <kvalo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org>, llvm@lists.linux.dev, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, dri-devel@lists.freedesktop.org, linux-toolchains@vger.kernel.org Subject: Re: Linux 6.3-rc3 Date: Wed, 22 Mar 2023 13:36:00 -0700 [thread overview] Message-ID: <20230322203600.GA2837284@dev-arch.thelio-3990X> (raw) In-Reply-To: <20230322163637.GA918620@dev-arch.thelio-3990X> On Wed, Mar 22, 2023 at 09:36:37AM -0700, Nathan Chancellor wrote: > On Wed, Mar 22, 2023 at 02:44:47PM +0200, Kalle Valo wrote: > > Nathan Chancellor <nathan@kernel.org> writes: > > > > > On Mon, Mar 20, 2023 at 11:26:17AM -0700, Linus Torvalds wrote: > > >> On Mon, Mar 20, 2023 at 11:05 AM Nathan Chancellor <nathan@kernel.org> wrote: > > >> > > > >> > On the clang front, I am still seeing the following warning turned error > > >> > for arm64 allmodconfig at least: > > >> > > > >> > drivers/gpu/host1x/dev.c:520:6: error: variable 'syncpt_irq' is uninitialized when used here [-Werror,-Wuninitialized] > > >> > if (syncpt_irq < 0) > > >> > ^~~~~~~~~~ > > >> > > >> Hmm. I do my arm64 allmodconfig builds with gcc, and I'm surprised > > >> that gcc doesn't warn about this. > > > > > > Perhaps these would make doing allmodconfig builds with clang more > > > frequently less painful for you? > > > > > > https://lore.kernel.org/llvm/20230319235619.GA18547@dev-arch.thelio-3990X/ > > > > Thank you, at least for me this is really helpful. > > Really glad to hear! I hope this helps make testing and verifying > changes with clang and LLVM easier for developers and maintainers. > > > I tried now clang for the first time but seeing a strange problem. > > > > I prefer to define the compiler in GNUmakefile so it's easy to change > > compilers and I don't need to remember the exact command line. So I have > > this in the top level GNUmakefile (all the rest commented out): > > > > LLVM=/opt/clang/llvm-16.0.0/bin/ > > > > If I run 'make oldconfig' it seems to use clang but after I run just > > 'make' it seems to switch back to the host GCC compiler and ask for GCC > > specific config questions again. Workaround for this seems to be adding > > 'export LLVM' to GNUmakefile, after that also 'make' uses clang as > > expected. > > Interesting... I just tested with a basic GNUmakefile and everything > seems to work fine without an export. At the same time, the export > should not hurt anything, so as long as it works, that is what matters. Ah, the export is needed so that mixed-build works properly (see lines 324 to 361 in Makefile), as 'make' will be called to process each target individually; without the export, LLVM is not set for the subsequent 'make' calls, so gcc is called. I just saw the same behavior as you did while testing with $ make -j(nproc) clean defconfig all without the export (GCC was used instead of LLVM). > $ gcc --version > fish: Unknown command: gcc > > > $ fd -t x . $CBL_TC_LLVM_STORE/16.0.0/bin -x basename > clang-16 > llvm-nm > llvm-objdump > llvm-objcopy > llvm-symbolizer > llvm-strings > llvm-readobj > llvm-dwarfdump > lld > llvm-ar > > > $ cat GNUmakefile > LLVM := $(CBL_TC_LLVM_STORE)/16.0.0/bin/ > > include Makefile > > > $ make -sj(nproc) defconfig > > > $ head -13 .config > # > # Automatically generated file; DO NOT EDIT. > # Linux/x86 6.3.0-rc3 Kernel Configuration > # > CONFIG_CC_VERSION_TEXT="ClangBuiltLinux clang version 16.0.0" > CONFIG_GCC_VERSION=0 > CONFIG_CC_IS_CLANG=y > CONFIG_CLANG_VERSION=160000 > CONFIG_AS_IS_LLVM=y > CONFIG_AS_VERSION=160000 > CONFIG_LD_VERSION=0 > CONFIG_LD_IS_LLD=y > CONFIG_LLD_VERSION=160000 > > > $ make -sj(nproc) init/main.o > > > $ $CBL_TC_LLVM_STORE/16.0.0/bin/llvm-readelf -p .comment init/main.o > String dump of section '.comment': > [ 1] ClangBuiltLinux clang version 16.0.0 > > > I added an informational print and I always saw the correct value: > > diff --git a/Makefile b/Makefile > index a2c310df2145..070394c4cb8c 100644 > --- a/Makefile > +++ b/Makefile > @@ -431,6 +431,7 @@ HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null) > HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null) > > ifneq ($(LLVM),) > +$(info LLVM: $(LLVM)) > ifneq ($(filter %/,$(LLVM)),) > LLVM_PREFIX := $(LLVM) > else ifneq ($(filter -%,$(LLVM)),) > > If you have any further issues, please do not hesitate to reach out! > > Cheers, > Nathan >
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Chancellor <nathan@kernel.org> To: Kalle Valo <kvalo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, David Airlie <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, dri-devel@lists.freedesktop.org, linux-toolchains@vger.kernel.org, llvm@lists.linux.dev Subject: Re: Linux 6.3-rc3 Date: Wed, 22 Mar 2023 13:36:00 -0700 [thread overview] Message-ID: <20230322203600.GA2837284@dev-arch.thelio-3990X> (raw) In-Reply-To: <20230322163637.GA918620@dev-arch.thelio-3990X> On Wed, Mar 22, 2023 at 09:36:37AM -0700, Nathan Chancellor wrote: > On Wed, Mar 22, 2023 at 02:44:47PM +0200, Kalle Valo wrote: > > Nathan Chancellor <nathan@kernel.org> writes: > > > > > On Mon, Mar 20, 2023 at 11:26:17AM -0700, Linus Torvalds wrote: > > >> On Mon, Mar 20, 2023 at 11:05 AM Nathan Chancellor <nathan@kernel.org> wrote: > > >> > > > >> > On the clang front, I am still seeing the following warning turned error > > >> > for arm64 allmodconfig at least: > > >> > > > >> > drivers/gpu/host1x/dev.c:520:6: error: variable 'syncpt_irq' is uninitialized when used here [-Werror,-Wuninitialized] > > >> > if (syncpt_irq < 0) > > >> > ^~~~~~~~~~ > > >> > > >> Hmm. I do my arm64 allmodconfig builds with gcc, and I'm surprised > > >> that gcc doesn't warn about this. > > > > > > Perhaps these would make doing allmodconfig builds with clang more > > > frequently less painful for you? > > > > > > https://lore.kernel.org/llvm/20230319235619.GA18547@dev-arch.thelio-3990X/ > > > > Thank you, at least for me this is really helpful. > > Really glad to hear! I hope this helps make testing and verifying > changes with clang and LLVM easier for developers and maintainers. > > > I tried now clang for the first time but seeing a strange problem. > > > > I prefer to define the compiler in GNUmakefile so it's easy to change > > compilers and I don't need to remember the exact command line. So I have > > this in the top level GNUmakefile (all the rest commented out): > > > > LLVM=/opt/clang/llvm-16.0.0/bin/ > > > > If I run 'make oldconfig' it seems to use clang but after I run just > > 'make' it seems to switch back to the host GCC compiler and ask for GCC > > specific config questions again. Workaround for this seems to be adding > > 'export LLVM' to GNUmakefile, after that also 'make' uses clang as > > expected. > > Interesting... I just tested with a basic GNUmakefile and everything > seems to work fine without an export. At the same time, the export > should not hurt anything, so as long as it works, that is what matters. Ah, the export is needed so that mixed-build works properly (see lines 324 to 361 in Makefile), as 'make' will be called to process each target individually; without the export, LLVM is not set for the subsequent 'make' calls, so gcc is called. I just saw the same behavior as you did while testing with $ make -j(nproc) clean defconfig all without the export (GCC was used instead of LLVM). > $ gcc --version > fish: Unknown command: gcc > > > $ fd -t x . $CBL_TC_LLVM_STORE/16.0.0/bin -x basename > clang-16 > llvm-nm > llvm-objdump > llvm-objcopy > llvm-symbolizer > llvm-strings > llvm-readobj > llvm-dwarfdump > lld > llvm-ar > > > $ cat GNUmakefile > LLVM := $(CBL_TC_LLVM_STORE)/16.0.0/bin/ > > include Makefile > > > $ make -sj(nproc) defconfig > > > $ head -13 .config > # > # Automatically generated file; DO NOT EDIT. > # Linux/x86 6.3.0-rc3 Kernel Configuration > # > CONFIG_CC_VERSION_TEXT="ClangBuiltLinux clang version 16.0.0" > CONFIG_GCC_VERSION=0 > CONFIG_CC_IS_CLANG=y > CONFIG_CLANG_VERSION=160000 > CONFIG_AS_IS_LLVM=y > CONFIG_AS_VERSION=160000 > CONFIG_LD_VERSION=0 > CONFIG_LD_IS_LLD=y > CONFIG_LLD_VERSION=160000 > > > $ make -sj(nproc) init/main.o > > > $ $CBL_TC_LLVM_STORE/16.0.0/bin/llvm-readelf -p .comment init/main.o > String dump of section '.comment': > [ 1] ClangBuiltLinux clang version 16.0.0 > > > I added an informational print and I always saw the correct value: > > diff --git a/Makefile b/Makefile > index a2c310df2145..070394c4cb8c 100644 > --- a/Makefile > +++ b/Makefile > @@ -431,6 +431,7 @@ HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null) > HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null) > > ifneq ($(LLVM),) > +$(info LLVM: $(LLVM)) > ifneq ($(filter %/,$(LLVM)),) > LLVM_PREFIX := $(LLVM) > else ifneq ($(filter -%,$(LLVM)),) > > If you have any further issues, please do not hesitate to reach out! > > Cheers, > Nathan >
next prev parent reply other threads:[~2023-03-22 20:36 UTC|newest] Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-19 20:50 Linux 6.3-rc3 Linus Torvalds 2023-03-20 8:21 ` Build regressions/improvements in v6.3-rc3 Geert Uytterhoeven 2023-03-21 5:38 ` Build regressions/improvements in v6.3-rc3 (drm/msm/) Randy Dunlap 2023-03-21 5:38 ` Randy Dunlap 2023-03-21 7:34 ` Geert Uytterhoeven 2023-03-21 7:34 ` Geert Uytterhoeven 2023-03-21 15:10 ` Randy Dunlap 2023-03-21 15:10 ` Randy Dunlap 2023-03-21 15:33 ` Geert Uytterhoeven 2023-03-21 15:33 ` Geert Uytterhoeven 2023-03-20 18:05 ` Linux 6.3-rc3 Nathan Chancellor 2023-03-20 18:05 ` Nathan Chancellor 2023-03-20 18:26 ` Linus Torvalds 2023-03-20 18:26 ` Linus Torvalds 2023-03-20 18:49 ` Linus Torvalds 2023-03-20 18:49 ` Linus Torvalds 2023-03-20 18:56 ` Nathan Chancellor 2023-03-20 18:56 ` Nathan Chancellor 2023-03-20 19:05 ` Linus Torvalds 2023-03-20 19:05 ` Linus Torvalds 2023-03-20 18:53 ` Nathan Chancellor 2023-03-20 18:53 ` Nathan Chancellor 2023-03-20 19:22 ` Nathan Chancellor 2023-03-20 19:22 ` Nathan Chancellor 2023-03-22 12:44 ` Kalle Valo 2023-03-22 12:44 ` Kalle Valo 2023-03-22 16:36 ` Nathan Chancellor 2023-03-22 16:36 ` Nathan Chancellor 2023-03-22 20:36 ` Nathan Chancellor [this message] 2023-03-22 20:36 ` Nathan Chancellor 2023-03-24 10:54 ` Kalle Valo 2023-03-24 10:54 ` Kalle Valo 2023-03-24 15:11 ` Nathan Chancellor 2023-03-24 15:11 ` Nathan Chancellor 2023-03-24 15:23 ` Kalle Valo 2023-03-24 15:23 ` Kalle Valo 2023-03-28 19:07 ` Nathan Chancellor 2023-03-28 19:07 ` Nathan Chancellor 2023-03-29 8:39 ` Kalle Valo 2023-03-29 8:39 ` Kalle Valo 2023-03-22 16:40 ` Sedat Dilek 2023-03-22 16:40 ` Sedat Dilek 2023-03-22 16:55 ` Linus Torvalds 2023-03-22 16:55 ` Linus Torvalds 2023-03-22 18:17 ` Nick Desaulniers 2023-03-22 18:17 ` Nick Desaulniers 2023-03-24 17:16 ` Masahiro Yamada 2023-03-24 17:16 ` Masahiro Yamada 2023-03-27 16:12 ` Jani Nikula 2023-03-27 16:12 ` Jani Nikula 2023-03-27 17:03 ` Kalle Valo 2023-03-27 17:03 ` Kalle Valo 2023-03-20 20:04 ` Guenter Roeck 2023-03-20 20:04 ` Guenter Roeck 2023-03-20 20:30 ` Linus Torvalds 2023-03-20 20:30 ` Linus Torvalds 2023-03-20 22:06 ` Nathan Chancellor 2023-03-20 22:06 ` Nathan Chancellor 2023-03-20 22:48 ` Segher Boessenkool 2023-03-20 22:48 ` Segher Boessenkool 2023-03-20 23:41 ` Linus Torvalds 2023-03-20 23:41 ` Linus Torvalds 2023-03-24 9:41 ` Daniel Vetter 2023-03-24 9:41 ` Daniel Vetter 2023-03-20 20:07 ` Guenter Roeck
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