helloworld-go: add Makefile

Author: bigwhite

ebpf-examples/helloworld-go/Makefile

@@ -0,0 +1,13 @@
+CLANG ?= clang-10
+CFLAGS ?= -O2 -g -Wall -Werror
+
+LIBEBPF_TOP = /home/tonybai/go/src/github.com/cilium/ebpf
+EXAMPLES_HEADERS = $(LIBEBPF_TOP)/examples/headers
+
+all: generate
+
+generate: export BPF_CLANG=$(CLANG)
+generate: export BPF_CFLAGS=$(CFLAGS)
+generate: export BPF_HEADERS=$(EXAMPLES_HEADERS)
+generate:
+	go generate ./...

ebpf-examples/helloworld-go/main.go

@@ -13,6 +13,8 @@ import (
 	"github.com/cilium/ebpf/rlimit"
 )
 
+// $BPF_CLANG, $BPF_CFLAGS and $BPF_HEADERS are set by the Makefile.
+//go:generate bpf2go -cc $BPF_CLANG -cflags $BPF_CFLAGS -target bpfel,bpfeb bpf helloworld.bpf.c -- -I $BPF_HEADERS
 func main() {
 	stopper := make(chan os.Signal, 1)
 	signal.Notify(stopper, os.Interrupt, syscall.SIGTERM)