On Fri, Aug 21, 2020 at 7:10 AM 'Nick Desaulniers' via Clang Built Linux clang-built-linux@googlegroups.com wrote:
While moving Android kernels over to use LLVM=1, we observe the failure when building in a hermetic docker image: HOSTCC scripts/basic/fixdep clang: error: unable to execute command: Executable "ld" doesn't exist!
The is because the build of the host utility fixdep builds the fixdep executable in one step by invoking the compiler as the driver, rather than individual compile then link steps.
Clang when configured from source defaults to use the system's linker, and not LLVM's own LLD, unless the CMake config -DCLANG_DEFAULT_LINKER='lld' is set when configuring a build of clang itself.
Don't rely on the compiler's implicit default linker; be explicit.
I do not understand this patch.
The host compiler should be able to link executables without any additional settings.
So, can you link a hello world program in your docker?
masahiro@zoe:~$ cat test.c #include <stdio.h> int main(void) { printf("helloworld\n"); return 0; } masahiro@zoe:~$ clang test.c
If this fails, your environment is broken.
Just do -DCLANG_DEFAULT_LINKER='lld' if you know GNU ld is missing in your docker environment.
Cc: stable@vger.kernel.org Fixes: commit a0d1c951ef08 ("kbuild: support LLVM=1 to switch the default tools to Clang/LLVM") Reported-by: Matthias Maennich maennich@google.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com
Makefile | 1 + 1 file changed, 1 insertion(+)
diff --git a/Makefile b/Makefile index def590b743a9..b4e93b228a26 100644 --- a/Makefile +++ b/Makefile @@ -436,6 +436,7 @@ OBJDUMP = llvm-objdump READELF = llvm-readelf OBJSIZE = llvm-size STRIP = llvm-strip +KBUILD_HOSTLDFLAGS += -fuse-ld=lld else CC = $(CROSS_COMPILE)gcc LD = $(CROSS_COMPILE)ld -- 2.28.0.297.g1956fa8f8d-goog
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