build failure about pwru

[zhangbo1882]

issue has been fixed.

[zhangbo1882]

KProbePWRUObjects should have nothing with Go version.

[brb]

@zhangbo1882 Hey, have you run go generate . before running go build .?

[zhangbo1882]

@brb
[Tue Oct 19 02:16:01][#107# ] (master)$go generate .
/home/stack/go/src/github.com/zhangbo1882/pwru/bpf/kprobe_pwru.c:238:14: error: use of unknown builtin '__builtin_btf_type_id' [-Wimplicit-function-declaration]
p.type_id = bpf_core_type_id_kernel(struct sk_buff);
^
./bpf/headers/bpf_core_read.h:145:2: note: expanded from macro 'bpf_core_type_id_kernel'
__builtin_btf_type_id(*(typeof(type) )0, BPF_TYPE_ID_TARGET)
^
/home/stack/go/src/github.com/zhangbo1882/pwru/bpf/kprobe_pwru.c:238:14: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference]
p.type_id = bpf_core_type_id_kernel(struct sk_buff);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./bpf/headers/bpf_core_read.h:145:24: note: expanded from macro 'bpf_core_type_id_kernel'
__builtin_btf_type_id((typeof(type) )0, BPF_TYPE_ID_TARGET)
^~~~~~~~~~~~~~~~~~
/home/stack/go/src/github.com/zhangbo1882/pwru/bpf/kprobe_pwru.c:238:14: note: consider using __builtin_trap() or qualifying pointer with 'volatile'
./bpf/headers/bpf_core_read.h:145:24: note: expanded from macro 'bpf_core_type_id_kernel'
__builtin_btf_type_id((typeof(type) *)0, BPF_TYPE_ID_TARGET)
^
/home/stack/go/src/github.com/zhangbo1882/pwru/bpf/kprobe_pwru.c:267:21: warning: taking address of packed member 'print_skb_id' of class or structure 'event_t' may result in an unaligned pointer value [-Waddress-of-packed-member]
set_skb_btf(skb, &event->print_skb_id);
^~~~~~~~~~~~~~~~~~~
2 warnings and 1 error generated.
Error: clang: exit status 1
exit status 1
main.go:28: running "go": exit status 1

[twpayne]

What version of clang are you using, i.e. what is the output of:

$ clang --version

You need Clang version 12 or later. Depending on your distribution, you may also have to update the //go:generate lines in main.go to use clang-12 instead of clang:

diff --git a/main.go b/main.go
index 2d9428e..f279ae1 100644
--- a/main.go
+++ b/main.go
@@ -25,8 +25,8 @@ import (
        "github.com/cilium/pwru/internal/pwru"
 )
 
-//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc clang KProbePWRU ./bpf/kprobe_pwru.c -- -DOUTPUT_SKB -I./bpf/headers
-//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc clang KProbePWRUWithoutOutputSKB ./bpf/kprobe_pwru.c -- -I./bpf/headers
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc clang-12 KProbePWRU ./bpf/kprobe_pwru.c -- -DOUTPUT_SKB -I./bpf/headers
+//go:generate go run github.com/cilium/ebpf/cmd/bpf2go -cc clang-12 KProbePWRUWithoutOutputSKB ./bpf/kprobe_pwru.c -- -I./bpf/headers
 
 func main() {
        var (

and then re-run go generate.