compile error while running make in example/c

[ANOLASC]

git clone and git submodule update --init --recursive
run make in example/c dir

BPF      .output/usdt.bpf.o
In file included from usdt.bpf.c:6:
.output/bpf/usdt.bpf.h:94:7: error: use of unknown builtin '__builtin_preserve_enum_value' [-Wimplicit-function-declaration]
        if (!BPF_USDT_HAS_BPF_COOKIE) {
             ^
.output/bpf/usdt.bpf.h:39:2: note: expanded from macro 'BPF_USDT_HAS_BPF_COOKIE'
        bpf_core_enum_value_exists(enum bpf_func_id___usdt, BPF_FUNC_get_attach_cookie___usdt)
        ^
.output/bpf/bpf_core_read.h:205:2: note: expanded from macro 'bpf_core_enum_value_exists'
        __builtin_preserve_enum_value(*(typeof(enum_type) *)enum_value, BPF_ENUMVAL_EXISTS)
        ^
1 error generated.
make: *** [Makefile:106: .output/usdt.bpf.o] Error 1

ubuntu 20.04 with 5.13.0-52-generic kernel

[chenhengqi]

You can either update your LLVM or apply the following diff:

diff --git a/examples/c/usdt.bpf.c b/examples/c/usdt.bpf.c
index 418aa48..ce6eedd 100644
--- a/examples/c/usdt.bpf.c
+++ b/examples/c/usdt.bpf.c
@@ -3,6 +3,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
+#define BPF_USDT_HAS_BPF_COOKIE 0
 #include <bpf/usdt.bpf.h>
 
 pid_t my_pid;

[ANOLASC]

You can either update your LLVM or apply the following diff:

diff --git a/examples/c/usdt.bpf.c b/examples/c/usdt.bpf.c
index 418aa48..ce6eedd 100644
--- a/examples/c/usdt.bpf.c
+++ b/examples/c/usdt.bpf.c
@@ -3,6 +3,7 @@
 #include <vmlinux.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
+#define BPF_USDT_HAS_BPF_COOKIE 0
 #include <bpf/usdt.bpf.h>
 
 pid_t my_pid;

Applied it. Now have a new error

  BPF      .output/usdt.bpf.o
  GEN-SKEL .output/usdt.skel.h
libbpf: sec '.relusdt/libc.so.6:libc:setjmp': corrupted symbol #25 pointing to invalid section #65522 for relo #3
Error: failed to open BPF object file: BPF object format invalid
make: *** [Makefile:112: .output/usdt.skel.h] Error 95
make: *** Deleting file '.output/usdt.skel.h'

[anakryiko]

@ANOLASC, please try to repull libbpf-bootstrap (we've updated libbpf and other stuff meanwhile) and try again? You shouldn't need BPF_USDT_HAS_BPF_COOKIE anymore, btw.

Please also make sure you are using a decently recent LLVM/Clang (as recent as you can). Please also report what Clang version you are using. Thanks.

[ANOLASC]

@ANOLASC, please try to repull libbpf-bootstrap (we've updated libbpf and other stuff meanwhile) and try again? You shouldn't need BPF_USDT_HAS_BPF_COOKIE anymore, btw.

Please also make sure you are using a decently recent LLVM/Clang (as recent as you can). Please also report what Clang version you are using. Thanks.

Still got the same error issue-1313523553.

I use apt to install clang.

clang --version

clang version 10.0.0-4ubuntu1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

[anakryiko]

Clang 10 is pretty old. Try upgrading to something newer. Also please check that your Clang supports BPF target.

[ANOLASC]

Clang 10 is pretty old. Try upgrading to something newer. Also please check that your Clang supports BPF target.

Make success by upgrading clang to 15. Thx.