| Message ID | 20220523152044.3905809-1-yhs@fb.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 4050764cbaa25760aab40857f723393c07898474 |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] selftests/bpf: fix btf_dump/btf_dump due to recent clang change | expand |
Hello: This patch was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Mon, 23 May 2022 08:20:44 -0700 you wrote: > Latest llvm-project upstream had a change of behavior > related to qualifiers on function return type ([1]). > This caused selftests btf_dump/btf_dump failure. > The following example shows what changed. > > $ cat t.c > typedef const char * const (* const (* const fn_ptr_arr2_t[5])())(char * (*)(int)); > struct t { > int a; > fn_ptr_arr2_t l; > }; > int foo(struct t *arg) { > return arg->a; > } > > [...] Here is the summary with links: - [bpf-next] selftests/bpf: fix btf_dump/btf_dump due to recent clang change https://git.kernel.org/bpf/bpf-next/c/4050764cbaa2 You are awesome, thank you!
diff --git a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c index 1c7105fcae3c..4ee4748133fe 100644 --- a/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c +++ b/tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c @@ -94,7 +94,7 @@ typedef void (* (*signal_t)(int, void (*)(int)))(int); typedef char * (*fn_ptr_arr1_t[10])(int **); -typedef char * (* const (* const fn_ptr_arr2_t[5])())(char * (*)(int)); +typedef char * (* (* const fn_ptr_arr2_t[5])())(char * (*)(int)); struct struct_w_typedefs { int_t a;
Latest llvm-project upstream had a change of behavior related to qualifiers on function return type ([1]). This caused selftests btf_dump/btf_dump failure. The following example shows what changed. $ cat t.c typedef const char * const (* const (* const fn_ptr_arr2_t[5])())(char * (*)(int)); struct t { int a; fn_ptr_arr2_t l; }; int foo(struct t *arg) { return arg->a; } Compiled with latest upstream llvm15, $ clang -O2 -g -target bpf -S -emit-llvm t.c The related generated debuginfo IR looks like: !16 = !DIDerivedType(tag: DW_TAG_typedef, name: "fn_ptr_arr2_t", file: !1, line: 1, baseType: !17) !17 = !DICompositeType(tag: DW_TAG_array_type, baseType: !18, size: 320, elements: !32) !18 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !19) !19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64) !20 = !DISubroutineType(types: !21) !21 = !{!22, null} !22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !23, size: 64) !23 = !DISubroutineType(types: !24) !24 = !{!25, !28} !25 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !26, size: 64) !26 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !27) !27 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) You can see two intermediate const qualifier to pointer are dropped in debuginfo IR. With llvm14, we have following debuginfo IR: !16 = !DIDerivedType(tag: DW_TAG_typedef, name: "fn_ptr_arr2_t", file: !1, line: 1, baseType: !17) !17 = !DICompositeType(tag: DW_TAG_array_type, baseType: !18, size: 320, elements: !34) !18 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !19) !19 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !20, size: 64) !20 = !DISubroutineType(types: !21) !21 = !{!22, null} !22 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !23) !23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !24, size: 64) !24 = !DISubroutineType(types: !25) !25 = !{!26, !30} !26 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !27) !27 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !28, size: 64) !28 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !29) !29 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char) All const qualifiers are preserved. To adapt the selftest to both old and new llvm, this patch removed the intermediate const qualifier in const-to-ptr types, to make the test succeed again. [1] https://reviews.llvm.org/D125919 Reported-by: Mykola Lysenko <mykolal@fb.com> Signed-off-by: Yonghong Song <yhs@fb.com> --- tools/testing/selftests/bpf/progs/btf_dump_test_case_syntax.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)