diff mbox series

[bpf-next,2/4] selftests/bpf: add __sink() macro to fake variable consumption

Message ID 20230309054015.4068562-3-andrii@kernel.org (mailing list archive)
State Accepted
Commit 713461b895ef958ef444b00cc2d979f3ca3a82e2
Delegated to: BPF
Headers show
Series selftests/bpf: make BPF_CFLAGS stricter with -Wall | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 20 this patch: 20
netdev/cc_maintainers warning 12 maintainers not CCed: eddyz87@gmail.com mykolal@fb.com song@kernel.org shuah@kernel.org sdf@google.com haoluo@google.com yhs@fb.com john.fastabend@gmail.com kpsingh@kernel.org jolsa@kernel.org martin.lau@linux.dev linux-kselftest@vger.kernel.org
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 20 this patch: 20
netdev/checkpatch fail ERROR: Macros with complex values should be enclosed in parentheses
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR success PR summary
bpf/vmtest-bpf-next-VM_Test-1 success Logs for ShellCheck
bpf/vmtest-bpf-next-VM_Test-6 success Logs for build for x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-7 success Logs for llvm-toolchain
bpf/vmtest-bpf-next-VM_Test-8 success Logs for set-matrix
bpf/vmtest-bpf-next-VM_Test-2 success Logs for build for aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-3 success Logs for build for aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-5 success Logs for build for x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-4 success Logs for build for s390x with gcc
bpf/vmtest-bpf-next-VM_Test-12 success Logs for test_maps on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-13 success Logs for test_maps on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-17 success Logs for test_progs on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-19 success Logs for test_progs_no_alu32 on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-22 success Logs for test_progs_no_alu32 on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-23 success Logs for test_progs_no_alu32 on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-24 success Logs for test_progs_no_alu32_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-26 success Logs for test_progs_no_alu32_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-27 success Logs for test_progs_no_alu32_parallel on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-28 success Logs for test_progs_parallel on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-30 success Logs for test_progs_parallel on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-31 success Logs for test_progs_parallel on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-32 success Logs for test_verifier on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-35 success Logs for test_verifier on x86_64 with gcc
bpf/vmtest-bpf-next-VM_Test-36 success Logs for test_verifier on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-9 success Logs for test_maps on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-10 success Logs for test_maps on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-14 success Logs for test_progs on aarch64 with gcc
bpf/vmtest-bpf-next-VM_Test-15 success Logs for test_progs on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-18 success Logs for test_progs on x86_64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-20 fail Logs for test_progs_no_alu32 on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-25 success Logs for test_progs_no_alu32_parallel on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-29 success Logs for test_progs_parallel on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-33 success Logs for test_verifier on aarch64 with llvm-17
bpf/vmtest-bpf-next-VM_Test-34 success Logs for test_verifier on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-21 success Logs for test_progs_no_alu32 on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-16 success Logs for test_progs on s390x with gcc
bpf/vmtest-bpf-next-VM_Test-11 success Logs for test_maps on s390x with gcc

Commit Message

Andrii Nakryiko March 9, 2023, 5:40 a.m. UTC 
Add __sink(expr) macro that forces compiler to believe that passed in
expression is both read and written. It used a simple embedded asm for
this. This is useful in a lot of tests where we assign value to some variable
to trigger some action, but later don't read variable, causing compiler
to complain (if corresponding compiler warnings are turned on, which
we'll do in the next patch).

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/testing/selftests/bpf/progs/bpf_misc.h | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/progs/bpf_misc.h b/tools/testing/selftests/bpf/progs/bpf_misc.h
index c95eb603403c..3c03ec8056ce 100644
--- a/tools/testing/selftests/bpf/progs/bpf_misc.h
+++ b/tools/testing/selftests/bpf/progs/bpf_misc.h
@@ -76,6 +76,9 @@ 
 #define FUNC_REG_ARG_CNT 5
 #endif
 
+/* make it look to compiler like value is read and written */
+#define __sink(expr) asm volatile("" : "+g"(expr))
+
 struct bpf_iter_num;
 
 extern int bpf_iter_num_new(struct bpf_iter_num *it, int start, int end) __ksym;