From: Fangrui Song <maskray@xxxxxxxxxx> commit ca9b31f6bb9c6aa9b4e5f0792f39a97bbffb8c51 upstream. When CROSS_COMPILE is set (e.g. aarch64-linux-gnu-), if $(CROSS_COMPILE)elfedit is found at /usr/bin/aarch64-linux-gnu-elfedit, GCC_TOOLCHAIN_DIR will be set to /usr/bin/. --prefix= will be set to /usr/bin/ and Clang as of 11 will search for both $(prefix)aarch64-linux-gnu-$needle and $(prefix)$needle. GCC searchs for $(prefix)aarch64-linux-gnu/$version/$needle, $(prefix)aarch64-linux-gnu/$needle and $(prefix)$needle. In practice, $(prefix)aarch64-linux-gnu/$needle rarely contains executables. To better model how GCC's -B/--prefix takes in effect in practice, newer Clang (since https://github.com/llvm/llvm-project/commit/3452a0d8c17f7166f479706b293caf6ac76ffd90) only searches for $(prefix)$needle. Currently it will find /usr/bin/as instead of /usr/bin/aarch64-linux-gnu-as. Set --prefix= to $(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) (/usr/bin/aarch64-linux-gnu-) so that newer Clang can find the appropriate cross compiling GNU as (when -no-integrated-as is in effect). Cc: stable@xxxxxxxxxxxxxxx Reported-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Signed-off-by: Fangrui Song <maskray@xxxxxxxxxx> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Tested-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Tested-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Link: https://github.com/ClangBuiltLinux/linux/issues/1099 Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/Makefile +++ b/Makefile @@ -482,7 +482,7 @@ ifeq ($(cc-name),clang) ifneq ($(CROSS_COMPILE),) CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%)) GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit)) -CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR) +CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE)) GCC_TOOLCHAIN := $(realpath $(GCC_TOOLCHAIN_DIR)/..) endif ifneq ($(GCC_TOOLCHAIN),)
