[PATCH bpf-next v6 6/9] selftests/bpf: derive the bench object list from the sources

The bench binary links every benchs/bench_*.c object, but the link
rule names them one by one in a hand-maintained list - adding a
benchmark means writing its name three times (source file, skeleton
dependency line, link list). Derive the list with a wildcard, as the
per-object skeleton dependency lines already imply: any bench_*.c
placed in benchs/ is compiled and linked in.

The derived list is sorted, which changes the link order of the bench
objects (previously roughly chronological) and with it the symbol
layout of the binary; no benchmark behaves differently. The trailing
'#' terminator goes away: the list now ends in a variable, so the
append-friendliness it provided no longer applies.

Signed-off-by: Mykola Lysenko <[email protected]>
---
 tools/testing/selftests/bpf/Makefile | 28 ++++------------------------
 1 file changed, 4 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 2a99b040301a..fdedfab25d72 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -956,7 +956,8 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
 	$(call msg,CXX,,$@)
 	$(Q)$(CXX) $(CXXFLAGS) $(filter %.a %.o %.cpp,$^) $(LDLIBS) -o $@
 
-# Benchmark runner
+# Benchmark runner. Every benchs/bench_*.c is compiled and linked in.
+BENCH_OBJS := $(sort $(patsubst benchs/%.c,$(OUTPUT)/%.o,$(wildcard benchs/bench_*.c)))
 $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
 	$(call msg,CC,,$@)
 	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@ $(call skip_on_fail,BENCH)
@@ -987,30 +988,9 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \
 		 $(TESTING_HELPERS) \
 		 $(TRACE_HELPERS) \
 		 $(CGROUP_HELPERS) \
-		 $(OUTPUT)/bench_count.o \
-		 $(OUTPUT)/bench_rename.o \
-		 $(OUTPUT)/bench_trigger.o \
-		 $(OUTPUT)/bench_ringbufs.o \
-		 $(OUTPUT)/bench_bloom_filter_map.o \
-		 $(OUTPUT)/bench_bpf_loop.o \
-		 $(OUTPUT)/bench_bpf_for.o \
-		 $(OUTPUT)/bench_strncmp.o \
-		 $(OUTPUT)/bench_bpf_hashmap_full_update.o \
-		 $(OUTPUT)/bench_local_storage.o \
-		 $(OUTPUT)/bench_local_storage_rcu_tasks_trace.o \
-		 $(OUTPUT)/bench_bpf_hashmap_lookup.o \
-		 $(OUTPUT)/bench_local_storage_create.o \
-		 $(OUTPUT)/bench_htab_mem.o \
-		 $(OUTPUT)/bench_bpf_crypto.o \
-		 $(OUTPUT)/bench_sockmap.o \
-		 $(OUTPUT)/bench_lpm_trie_map.o \
-		 $(OUTPUT)/bench_bpf_timing.o \
-		 $(OUTPUT)/bench_bpf_nop.o \
-		 $(OUTPUT)/bench_xdp_lb.o \
-		 $(OUTPUT)/bench_libarena.o \
+		 $(BENCH_OBJS) \
 		 $(OUTPUT)/usdt_1.o \
-		 $(OUTPUT)/usdt_2.o \
-		 #
+		 $(OUTPUT)/usdt_2.o
 	$(call msg,BINARY,,$@)
 	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@ $(call skip_on_fail,LINK,,(some benchmarks may have been skipped))
 
-- 
2.43.0