[PATCH] selftests/bpf: add GCC compatible builtins to bpf_legacy.h

[James Hilliard]

The bpf_legacy.h header uses llvm specific load functions, add
GCC compatible variants as well to fix tests using these functions
under GCC.

Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx>
Cc: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx>
Cc: David Faust <david.faust@xxxxxxxxxx>
---
 tools/testing/selftests/bpf/bpf_legacy.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_legacy.h b/tools/testing/selftests/bpf/bpf_legacy.h
index 845209581440..256c2a90aa20 100644
--- a/tools/testing/selftests/bpf/bpf_legacy.h
+++ b/tools/testing/selftests/bpf/bpf_legacy.h
@@ -2,6 +2,15 @@
 #ifndef __BPF_LEGACY__
 #define __BPF_LEGACY__
 
+#if __GNUC__ && !__clang__
+/* Functions to emit BPF_LD_ABS and BPF_LD_IND instructions.  We
+ * provide the "standard" names as synonyms of the corresponding GCC
+ * builtins.  Note how the SKB argument is ignored.
+ */
+#define load_byte(skb,off) __builtin_bpf_load_byte((off))
+#define load_half(skb,off) __builtin_bpf_load_half((off))
+#define load_word(skb,off) __builtin_bpf_load_word((off))
+#else
 /* llvm builtin functions that eBPF C program may use to
  * emit BPF_LD_ABS and BPF_LD_IND instructions
  */
@@ -11,6 +20,7 @@ unsigned long long load_half(void *skb,
 			     unsigned long long off) asm("llvm.bpf.load.half");
 unsigned long long load_word(void *skb,
 			     unsigned long long off) asm("llvm.bpf.load.word");
+#endif
 
 #endif
 
-- 
2.34.1