From: Nathan Chancellor <nathan@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>,
Nicolas Schier <nsc@kernel.org>, Rong Xu <xur@google.com>,
Han Shen <shenhan@google.com>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev, stable@vger.kernel.org
Subject: [PATCH] kbuild: AutoFDO: Update split machine function argument for upstream rename
Date: Wed, 14 Oct 2026 16:40:41 -0700 [thread overview]
Message-ID: <20261014-update-autofdo-split-machine-function-option-v1-1-5c71b3005e89@kernel.org> (raw)
A recent LLVM commit [1] renamed the internal LLVM plugin option
'-split-machine-functions' to '-function-splitting=all', breaking the
AutoFDO + ThinLTO build with:
ld.lld: error: -plugin-opt=-: ld.lld: Unknown command line argument '-split-machine-functions'. Try: 'ld.lld --help'
The plugin option is needed for in-process ThinLTO, so handle the rename
accordingly using ld-option.
Cc: stable@vger.kernel.org
Closes: https://github.com/ClangBuiltLinux/linux/issues/2186
Fixes: 2fd65f7afd5a ("AutoFDO: Enable machine function split optimization for AutoFDO")
Link: https://github.com/llvm/llvm-project/commit/3e6acc87c58843e551d6e8e4bf06c26712b04622 [1]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
scripts/Makefile.autofdo | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/scripts/Makefile.autofdo b/scripts/Makefile.autofdo
index 1442043da139..57a3aba6ffc2 100644
--- a/scripts/Makefile.autofdo
+++ b/scripts/Makefile.autofdo
@@ -22,7 +22,7 @@ ifdef CONFIG_LTO_CLANG_THIN
KBUILD_LDFLAGS += --lto-sample-profile=$(CLANG_AUTOFDO_PROFILE)
endif
KBUILD_LDFLAGS += --mllvm=-enable-fs-discriminator=true --mllvm=-improved-fs-discriminator=true -plugin-opt=thinlto
- KBUILD_LDFLAGS += -plugin-opt=-split-machine-functions
+ KBUILD_LDFLAGS += $(call ld-option,-plugin-opt=-function-splitting=all,-plugin-opt=-split-machine-functions)
endif
export CFLAGS_AUTOFDO_CLANG RUSTFLAGS_AUTOFDO_CLANG
---
base-commit: 24a19b953e2a3d0ea5a8c4951a0ab8f32720c907
change-id: 20261014-update-autofdo-split-machine-function-option-d4edb03d370c
Best regards,
--
Cheers,
Nathan
reply other threads:[~2026-10-14 23:40 UTC|newest]
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