From 4670d68b9254710fdeaf794cad54d8b2c9929e0a Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Wed, 25 Sep 2019 11:52:05 -0700 Subject: selftests/bpf: adjust strobemeta loop to satisfy latest clang Some recent changes in latest Clang started causing the following warning when unrolling strobemeta test case main loop: progs/strobemeta.h:416:2: warning: loop not unrolled: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning] This patch simplifies loop's exit condition to depend only on constant max iteration number (STROBE_MAX_MAP_ENTRIES), while moving early termination logic inside the loop body. The changes are equivalent from program logic standpoint, but fixes the warning. It also appears to improve generated BPF code, as it fixes previously failing non-unrolled strobemeta test cases. Cc: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/progs/strobemeta.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'tools') diff --git a/tools/testing/selftests/bpf/progs/strobemeta.h b/tools/testing/selftests/bpf/progs/strobemeta.h index 8a399bdfd920..067eb625d01c 100644 --- a/tools/testing/selftests/bpf/progs/strobemeta.h +++ b/tools/testing/selftests/bpf/progs/strobemeta.h @@ -413,7 +413,10 @@ static __always_inline void *read_map_var(struct strobemeta_cfg *cfg, #else #pragma unroll #endif - for (int i = 0; i < STROBE_MAX_MAP_ENTRIES && i < map.cnt; ++i) { + for (int i = 0; i < STROBE_MAX_MAP_ENTRIES; ++i) { + if (i >= map.cnt) + break; + descr->key_lens[i] = 0; len = bpf_probe_read_str(payload, STROBE_MAX_STR_LEN, map.entries[i].key); -- cgit v1.2.3