From c09cc93694a56ab86d2937cd36cb8fa397776c9d Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Thu, 10 Oct 2019 20:29:01 -0700 Subject: [PATCH] libbpf: Handle invalid typedef emitted by old GCC Old GCC versions are producing invalid typedef for __gnuc_va_list pointing to void. Special-case this and emit valid: typedef __builtin_va_list __gnuc_va_list; Reported-by: John Fastabend Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Martin KaFai Lau Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20191011032901.452042-1-andriin@fb.com --- tools/lib/bpf/btf_dump.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 87f27e2664c5d..139812b46c7b9 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -975,6 +975,17 @@ static void btf_dump_emit_typedef_def(struct btf_dump *d, __u32 id, { const char *name = btf_dump_ident_name(d, id); + /* + * Old GCC versions are emitting invalid typedef for __gnuc_va_list + * pointing to VOID. This generates warnings from btf_dump() and + * results in uncompilable header file, so we are fixing it up here + * with valid typedef into __builtin_va_list. + */ + if (t->type == 0 && strcmp(name, "__gnuc_va_list") == 0) { + btf_dump_printf(d, "typedef __builtin_va_list __gnuc_va_list"); + return; + } + btf_dump_printf(d, "typedef "); btf_dump_emit_type_decl(d, t->type, name, lvl); } -- 2.39.5