On Tue, Feb 06, 2024 at 12:05:29PM +0100, Daniel Bristot de Oliveira wrote: > The following errors are showing up when compiling rtla with clang: > > $ make HOSTCC=clang CC=clang LLVM_IAS=1 > [...] > > clang -O -g -DVERSION=\"6.8.0-rc1\" -flto=auto -ffat-lto-objects > -fexceptions -fstack-protector-strong > -fasynchronous-unwind-tables -fstack-clash-protection -Wall > -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 > -Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized > $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c > > clang: warning: optimization flag '-ffat-lto-objects' is not supported > [-Wignored-optimization-argument]
For what it's worth, this flag is supported in clang 17.0.0 and newer: https://github.com/llvm/llvm-project/commit/610fc5cbcc8b68879c562f6458608afe2473ab7f But if it is not critical, just dropping the flag like you have done here rather than conditionally supporting it is probably easier. > warning: unknown warning option '-Wno-maybe-uninitialized'; did you mean > '-Wno-uninitialized'? [-Wunknown-warning-option] > 1 warning generated. > > clang -o rtla -ggdb src/osnoise.o src/osnoise_hist.o src/osnoise_top.o > src/rtla.o src/timerlat_aa.o src/timerlat.o src/timerlat_hist.o > src/timerlat_top.o src/timerlat_u.o src/trace.o src/utils.o $(pkg-config > --libs libtracefs) > > src/osnoise.o: file not recognized: file format not recognized > clang: error: linker command failed with exit code 1 (use -v to see > invocation) > make: *** [Makefile:110: rtla] Error 1 > > Solve these issues by: > - removing -ffat-lto-objects and -Wno-maybe-uninitialized if using clang > - informing the linker about -flto=auto > > Cc: sta...@vger.kernel.org > Fixes: 1a7b22ab15eb ("tools/rtla: Build with EXTRA_{C,LD}FLAGS") > Suggested-by: Donald Zickus <dzic...@redhat.com> > Signed-off-by: Daniel Bristot de Oliveira <bris...@kernel.org> > --- > tools/tracing/rtla/Makefile | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/tools/tracing/rtla/Makefile b/tools/tracing/rtla/Makefile > index 2456a399eb9a..afd18c678ff5 100644 > --- a/tools/tracing/rtla/Makefile > +++ b/tools/tracing/rtla/Makefile > @@ -28,10 +28,15 @@ FOPTS := -flto=auto -ffat-lto-objects > -fexceptions -fstack-protector-strong \ > -fasynchronous-unwind-tables -fstack-clash-protection > WOPTS := -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 > -Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized > > +ifeq ($(CC),clang) > + FOPTS := $(filter-out -ffat-lto-objects, $(FOPTS)) > + WOPTS := $(filter-out -Wno-maybe-uninitialized, $(WOPTS)) > +endif > + > TRACEFS_HEADERS := $$($(PKG_CONFIG) --cflags libtracefs) > > CFLAGS := -O -g -DVERSION=\"$(VERSION)\" $(FOPTS) $(MOPTS) > $(WOPTS) $(TRACEFS_HEADERS) $(EXTRA_CFLAGS) > -LDFLAGS := -ggdb $(EXTRA_LDFLAGS) > +LDFLAGS := -flto=auto -ggdb $(EXTRA_LDFLAGS) > LIBS := $$($(PKG_CONFIG) --libs libtracefs) > > SRC := $(wildcard src/*.c) > -- > 2.43.0 >
