From 2b358510d5cc56164f83110ca1499c95a5a352cd Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Wed, 14 Oct 2026 16:40:41 -0700 Subject: [PATCH] kbuild: AutoFDO: Update split machine function argument for upstream rename 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] Link: https://patch.msgid.link/20261014-update-autofdo-split-machine-function-option-v1-1-5c71b3005e89@kernel.org Signed-off-by: Nathan Chancellor --- 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