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
