diff options
| author | Alexei Starovoitov <ast@kernel.org> | 2023-12-26 22:11:43 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-01-03 21:41:22 +0300 |
| commit | 495d2d8133fd1407519170a5238f455abbd9ec9b (patch) | |
| tree | 12f60945f5c43cbd7daaaf7be7e3594612a477c4 /tools/testing/selftests/bpf/Makefile | |
| parent | a640de4cf9fec0caf43ccb7404ec9f0fde9a6a65 (diff) | |
| download | linux-495d2d8133fd1407519170a5238f455abbd9ec9b.tar.xz | |
selftests/bpf: Attempt to build BPF programs with -Wsign-compare
GCC's -Wall includes -Wsign-compare while clang does not.
Since BPF programs are built with clang we need to add this flag explicitly
to catch problematic comparisons like:
int i = -1;
unsigned int j = 1;
if (i < j) // this is false.
long i = -1;
unsigned int j = 1;
if (i < j) // this is true.
C standard for reference:
- If either operand is unsigned long the other shall be converted to unsigned long.
- Otherwise, if one operand is a long int and the other unsigned int, then if a
long int can represent all the values of an unsigned int, the unsigned int
shall be converted to a long int; otherwise both operands shall be converted to
unsigned long int.
- Otherwise, if either operand is long, the other shall be converted to long.
- Otherwise, if either operand is unsigned, the other shall be converted to unsigned.
Unfortunately clang's -Wsign-compare is very noisy.
It complains about (s32)a == (u32)b which is safe and doen't have surprising behavior.
This patch fixes some of the issues. It needs a follow up to fix the rest.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20231226191148.48536-2-alexei.starovoitov@gmail.com
Diffstat (limited to 'tools/testing/selftests/bpf/Makefile')
| -rw-r--r-- | tools/testing/selftests/bpf/Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 617ae55c3bb5..fd15017ed3b1 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -383,6 +383,7 @@ CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH)) BPF_CFLAGS = -g -Wall -Werror -D__TARGET_ARCH_$(SRCARCH) $(MENDIAN) \ -I$(INCLUDE_DIR) -I$(CURDIR) -I$(APIDIR) \ -I$(abspath $(OUTPUT)/../usr/include) +# TODO: enable me -Wsign-compare CLANG_CFLAGS = $(CLANG_SYS_INCLUDES) \ -Wno-compare-distinct-pointer-types |