On 5/14/26 2:32 AM, James Clark wrote: > Building with LLVM=... could result in a different version of lld being > used than the main toolchain for liburandom_read.so because it's > hardcoded to "lld" in this makefile. > > Make it consistent with the rest of the LLVM toolchain by adding an LLD > variable to Makefile.include. Keep the fallback for other architectures > in tools/testing/selftests/bpf/Makefile as it seems like it's something > specific to this make rule and shouldn't be global. > > Clang accepts either a full path or "ld.lld-15" style inputs to > -fuse-ld= so this will work with LLD defined the same way as the other > LLVM tools. However, for full paths, we need to use ".../ld.lld" instead > of the generic driver "lld", but I don't think the original use of "lld" > was significant as this is always a linux build. > > Signed-off-by: James Clark <[email protected]> > --- > tools/scripts/Makefile.include | 2 ++ > tools/testing/selftests/bpf/Makefile | 8 ++++---- > 2 files changed, 6 insertions(+), 4 deletions(-) > > diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include > index 380ad84ac51e..5c2d505cba62 100644 > --- a/tools/scripts/Makefile.include > +++ b/tools/scripts/Makefile.include > @@ -67,6 +67,7 @@ ifneq ($(LLVM),) > $(call allow-override,HOSTAR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)) > $(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)) > $(call allow-override,HOSTLD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)) > + $(call allow-override,LLD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)) > $(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX)) > $(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)) > $(call allow-override,LLVM_STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)) > @@ -91,6 +92,7 @@ else > # Some tools still require Clang, LLC and/or LLVM utils > $(call allow-override,CLANG,clang) > $(call allow-override,LLC,llc) > + $(call allow-override,LLD,ld.lld) > $(call allow-override,LLVM_CONFIG,llvm-config) > $(call allow-override,LLVM_OBJCOPY,llvm-objcopy) > $(call allow-override,LLVM_STRIP,llvm-strip) > diff --git a/tools/testing/selftests/bpf/Makefile > b/tools/testing/selftests/bpf/Makefile > index 6ef6872adbc3..44ba829e5d4d 100644 > --- a/tools/testing/selftests/bpf/Makefile > +++ b/tools/testing/selftests/bpf/Makefile > @@ -245,9 +245,9 @@ $(OUTPUT)/%:%.c > > # LLVM's ld.lld doesn't support all the architectures, so use it only on x86 > ifeq ($(SRCARCH),$(filter $(SRCARCH),x86 riscv)) > -LLD := lld > +USE_LD := $(LLD) > else > -LLD := $(shell command -v $(LD)) > +USE_LD := $(shell command -v $(LD)) > endif > > # Filter out -static for liburandom_read.so and its dependent targets so > that static builds > @@ -258,7 +258,7 @@ $(OUTPUT)/liburandom_read.so: urandom_read_lib1.c > urandom_read_lib2.c liburandom > $(filter-out -static,$(CFLAGS) $(LDFLAGS)) \ > $(filter %.c,$^) $(filter-out -static,$(LDLIBS)) \ > -Wno-unused-command-line-argument \ > - -fuse-ld=$(LLD) -Wl,-znoseparate-code -Wl,--build-id=sha1 \ > + -fuse-ld=$(USE_LD) -Wl,-znoseparate-code > -Wl,--build-id=sha1 \
Hi James, This patch breaks the selftests/bpf build: $ clang --version clang version 22.1.3 (CentOS 22.1.3-1.el9) Target: x86_64-redhat-linux-gnu Thread model: posix InstalledDir: /usr/bin Configuration file: /etc/clang/x86_64-redhat-linux-gnu-clang.cfg $ make LLVM=1 -j$(nproc) [...] # ok $ make LLVM=1 -C tools/testing/selftests/bpf -j$(nproc) [...] # somewhere in the middle LIB liburandom_read.so clang: error: invalid linker name in argument '-fuse-ld=ld.lld' make: *** [Makefile:256: /home/isolodrai/workspace/review/linux/tools/testing/selftests/bpf/liburandom_read.so] Error 1 make: Leaving directory '/home/isolodrai/workspace/review/linux/tools/testing/selftests/bpf' [...] Or a simpler reproducer: $ make LLVM=1 OUTPUT=/tmp/out /tmp/out/liburandom_read.so LIB liburandom_read.so clang: error: invalid linker name in argument '-fuse-ld=ld.lld' make: *** [Makefile:256: /tmp/out/liburandom_read.so] Error 1 $ make LLVM=-22 OUTPUT=/tmp/out /tmp/out/liburandom_read.so LIB liburandom_read.so clang-22: error: invalid linker name in argument '-fuse-ld=ld.lld-22' make: *** [Makefile:256: /tmp/out/liburandom_read.so] Error 1 I tried your patches, and only then noticed BPF CI caught this too: https://github.com/kernel-patches/bpf/actions/runs/25943477658/job/76267174885?pr=12082 > -Wl,--version-script=liburandom_read.map \ > -fPIC -shared -o $@ > > @@ -268,7 +268,7 @@ $(OUTPUT)/urandom_read: urandom_read.c urandom_read_aux.c > $(OUTPUT)/liburandom_r > $(filter-out -static,$(CFLAGS) $(LDFLAGS)) $(filter > %.c,$^) \ > -Wno-unused-command-line-argument \ > -lurandom_read $(filter-out -static,$(LDLIBS)) -L$(OUTPUT) > \ > - -fuse-ld=$(LLD) -Wl,-znoseparate-code -Wl,--build-id=sha1 \ > + -fuse-ld=$(USE_LD) -Wl,-znoseparate-code > -Wl,--build-id=sha1 \ > -Wl,-rpath=. -o $@ > > $(OUTPUT)/sign-file: ../../../../scripts/sign-file.c >
