the clang-10 compile the __sync_add_and_fetch() fail in aarch64 bpf code

[wjefen]

<1>the error information is as follows:

1. parser at end of file
2. Code generation
3. Running pass 'Function Pass Manager' on module 'xxx.bpf.c'.
4. Running pass 'BPF PreEmit Checking' on function '@func'

<2>the x86-clang-9 or arm64/ -emit-llvm->opt->llvm-dis->llc is ok
<3>__atomic_fetch_add() alse error

Is it necessary to upgrade or is there a better way

[EugeneZelenko]

10 is very old. Could you please try 16 or main branch? https://godbolt.org should be helpful.

[asl]

We also need a minimal reproducible example

[wjefen]

1. After the clan-11 is compiled, the bpf code can be compiled using the clan of this version.

2.When the bpf program is being loaded, the following error information is displayed:
libbpf: prog 'proces_sxxx': BPF program load failed: ERROR: strerror_r(524)=22

3. Check the kernel code. The error logic is as follows. Error 524 corresponds to ENOTSUPP. my kernel version is 5.15.7.

   if (attr->attach_prog_fd) {
   dst_prog = bpf_prog_get(attr->attach_prog_fd);
   if (IS_ERR(dst_prog)) {
   dst_prog = NULL;
   attach_btf = btf_get_by_fd(attr->attach_btf_obj_fd);
   if (IS_ERR(attach_btf))
   return -EINVAL;
   if (!btf_is_kernel(attach_btf)) {
   /* attaching through specifying bpf_prog's BTF
   * objects directly might be supported eventually
   */
   btf_put(attach_btf);
   return -ENOTSUPP;
   }
   }
   }

4. Check the Linux update description and related code. This version supports atomic operations. If functions atomic64_add are used, a message is displayed.
   libbpf: failed to find BTF for extern'atomic64_add': - 2

5.Now we don't know how to solve this problem. Maybe it's not related to clang, or it's related to the bpf mechanism,
thanks for help

[Endilll]

@wjefen Do you still experience this with Clang 17 or trunk?

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

<1>the error information is as follows: 1. <eof> parser at end of file 2. Code generation 3. Running pass 'Function Pass Manager' on module 'xxx.bpf.c'. 4. Running pass 'BPF PreEmit Checking' on function '@func'

<2>the x86-clang-9 or arm64/ -emit-llvm->opt->llvm-dis->llc is ok
<3>__atomic_fetch_add() alse error

Is it necessary to upgrade or is there a better way