Hi everyone, This patch address the problem reported in: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113225
Looking forward to your review. Cheers, Cupertino This patch fix a problem with kernel_helper attribute BTF information, which incorrectly generates BTF_KIND_FUNC entry. This BTF entry although accurate with traditional extern function declarations, once the function is attributed with kernel_helper, it is semantically incompatible of the kernel helpers in BPF infrastructure. gcc/ChangeLog: PR target/113225 * btfout.cc (btf_collect_datasec): Skip creating BTF info for extern and kernel_helper attributed function decls. gcc/testsuite/ChangeLog: * gcc.target/bpf/attr-kernel-helper.c: New test. --- gcc/btfout.cc | 7 +++++++ gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c | 15 +++++++++++++++ 2 files changed, 22 insertions(+) create mode 100644 gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c diff --git a/gcc/btfout.cc b/gcc/btfout.cc index 04218adc9e66..39e7bec43bfb 100644 --- a/gcc/btfout.cc +++ b/gcc/btfout.cc @@ -35,6 +35,8 @@ along with GCC; see the file COPYING3. If not see #include "diagnostic-core.h" #include "cgraph.h" #include "varasm.h" +#include "stringpool.h" +#include "attribs.h" #include "dwarf2out.h" /* For lookup_decl_die. */ static int btf_label_num; @@ -429,6 +431,11 @@ btf_collect_datasec (ctf_container_ref ctfc) if (dtd == NULL) continue; + if (DECL_EXTERNAL (func->decl) + && (lookup_attribute ("kernel_helper", + DECL_ATTRIBUTES (func->decl))) != NULL_TREE) + continue; + /* Functions actually get two types: a BTF_KIND_FUNC_PROTO, and also a BTF_KIND_FUNC. But the CTF container only allocates one type per function, which matches closely with BTF_KIND_FUNC_PROTO. diff --git a/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c b/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c new file mode 100644 index 000000000000..7c5a0007c979 --- /dev/null +++ b/gcc/testsuite/gcc.target/bpf/attr-kernel-helper.c @@ -0,0 +1,15 @@ +/* Basic test for kernel_helper attribute BTF information. */ + +/* { dg-do compile } */ +/* { dg-options "-O0 -dA -gbtf" } */ + +extern int foo_helper(int) __attribute((kernel_helper(42))); +extern int foo_nohelper(int); + +int bar (int arg) +{ + return foo_helper (arg) + foo_nohelper (arg); +} + +/* { dg-final { scan-assembler-times "BTF_KIND_FUNC 'foo_nohelper'" 1 } } */ +/* { dg-final { scan-assembler-times "BTF_KIND_FUNC 'foo_helper'" 0 } } */ -- 2.30.2