[PATCH AUTOSEL 5.18 60/93] libbpf: Disable SEC pragma macro on GCC

Sasha Levin
2022-08-11T16:03:34Z

From: James Hilliard <james.hilliard1@gmail.com>

[ Upstream commit 18410251f66aee7e82234073ce6656ca20a732a9 ]

It seems the gcc preprocessor breaks with pragmas when surrounding
__attribute__.

Disable these pragmas on GCC due to upstream bugs see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400

Fixes errors like:
error: expected identifier or '(' before '#pragma'
106 | SEC("cgroup/bind6")
| ^~~

error: expected '=', ',', ';', 'asm' or '__attribute__' before '#pragma'
114 | char _license[] SEC("license") = "GPL";
| ^~~

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220706111839.1247911-1-james.hilliard1@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/lib/bpf/bpf_helpers.h | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 44df982d2a5c..e1ba0f3bb1ff 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -22,12 +22,25 @@
* To allow use of SEC() with externs (e.g., for extern .maps declarations),
* make sure __attribute__((unused)) doesn't trigger compilation warning.
*/
+#if __GNUC__ && !__clang__
+
+/*
+ * Pragma macros are broken on GCC
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55578
+ * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90400
+ */
+#define SEC(name) __attribute__((section(name), used))
+
+#else
+
#define SEC(name) \
_Pragma("GCC diagnostic push") \
_Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
__attribute__((section(name), used)) \
_Pragma("GCC diagnostic pop") \

+#endif
+
/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
#undef __always_inline
#define __always_inline inline __attribute__((always_inline))
--
2.35.1