[PATCH] libbpf: Fix build with latest gcc/binutils with LTO
From: Michal Suchanek <hidden>
Date: 2021-08-27 07:25:54
From: Patrick McCarty <redacted> After updating to binutils 2.35, the build began to fail with an assembler error. A bug was opened on the Red Hat Bugzilla a few days later for the same issue. Work around the problem by using the new `symver` attribute (introduced in GCC 10) as needed, instead of the `COMPAT_VERSION` and `DEFAULT_VERSION` macros, which expand to assembler directives. Fixes: https://github.com/libbpf/libbpf/issues/338 Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1863059 Fixes: https://bugzilla.opensuse.org/show_bug.cgi?id=1188749 Signed-off-by: Patrick McCarty <redacted> Make the change conditional on GCC version Signed-off-by: Michal Suchanek <redacted> --- tools/lib/bpf/libbpf_internal.h | 23 +++++++++++++++++------ tools/lib/bpf/xsk.c | 4 ++-- 2 files changed, 19 insertions(+), 8 deletions(-)
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index 016ca7cb4f8a..af0f3fb102c0 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h@@ -86,20 +86,31 @@ (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD)) #endif +#ifdef __GNUC__ +# if __GNUC__ >= 10 +# define DEFAULT_VERSION(internal_name, api_name, version) \ +__attribute__((__symver__(#api_name "@@" #version))) +# define COMPAT_VERSION(internal_name, api_name, version) \ +__attribute__((__symver__(#api_name "@" #version))) +# endif +#endif + +#if !defined(COMPAT_VERSION) || !defined(DEFAULT_VERSION) /* Symbol versioning is different between static and shared library. * Properly versioned symbols are needed for shared library, but * only the symbol of the new version is needed for static library. */ -#ifdef SHARED -# define COMPAT_VERSION(internal_name, api_name, version) \ +# ifdef SHARED +# define COMPAT_VERSION(internal_name, api_name, version) \ asm(".symver " #internal_name "," #api_name "@" #version); -# define DEFAULT_VERSION(internal_name, api_name, version) \ +# define DEFAULT_VERSION(internal_name, api_name, version) \ asm(".symver " #internal_name "," #api_name "@@" #version); -#else -# define COMPAT_VERSION(internal_name, api_name, version) -# define DEFAULT_VERSION(internal_name, api_name, version) \ +# else +# define COMPAT_VERSION(internal_name, api_name, version) +# define DEFAULT_VERSION(internal_name, api_name, version) \ extern typeof(internal_name) api_name \ __attribute__((alias(#internal_name))); +# endif #endif extern void libbpf_print(enum libbpf_print_level level,
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index e9b619aa0cdf..a2111696ba91 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c@@ -281,6 +281,7 @@ static int xsk_create_umem_rings(struct xsk_umem *umem, int fd, return err; } +DEFAULT_VERSION(xsk_umem__create_v0_0_4, xsk_umem__create, LIBBPF_0.0.4) int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, __u64 size, struct xsk_ring_prod *fill, struct xsk_ring_cons *comp,
@@ -345,6 +346,7 @@ struct xsk_umem_config_v1 { __u32 frame_headroom; }; +COMPAT_VERSION(xsk_umem__create_v0_0_2, xsk_umem__create, LIBBPF_0.0.2) int xsk_umem__create_v0_0_2(struct xsk_umem **umem_ptr, void *umem_area, __u64 size, struct xsk_ring_prod *fill, struct xsk_ring_cons *comp,
@@ -358,8 +360,6 @@ int xsk_umem__create_v0_0_2(struct xsk_umem **umem_ptr, void *umem_area, return xsk_umem__create_v0_0_4(umem_ptr, umem_area, size, fill, comp, &config); } -COMPAT_VERSION(xsk_umem__create_v0_0_2, xsk_umem__create, LIBBPF_0.0.2) -DEFAULT_VERSION(xsk_umem__create_v0_0_4, xsk_umem__create, LIBBPF_0.0.4) static enum xsk_prog get_xsk_prog(void) {
--
2.31.1