bpf2go,examples: remove deprecated +build tags from generated Go sources

To follow suit with the new //go:build convention of build tags, this commit converts bpf2go to no longer emit the deprecated +build ones. Specify that currently, all given tags are ORed together. Signed-off-by: Timo Beckers <timo@isovalent.com>
cilium · Dec 13, 2022 · e994bf4 · e994bf4
1 parent 9e4f448
commit e994bf4
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Showing 26 changed files with 23 additions and 38 deletions.
diff --git a/cmd/bpf2go/main.go b/cmd/bpf2go/main.go
@@ -76,7 +76,7 @@ func run(stdout io.Writer, pkg, outputDir string, args []string) (err error) {
 	fs.StringVar(&b2g.strip, "strip", "", "`binary` used to strip DWARF from compiled BPF (default \"llvm-strip\")")
 	fs.BoolVar(&b2g.disableStripping, "no-strip", false, "disable stripping of DWARF")
 	flagCFlags := fs.String("cflags", "", "flags passed to the compiler, may contain quoted arguments")
-	fs.StringVar(&b2g.tags, "tags", "", "list of Go build tags to include in generated files")
+	fs.StringVar(&b2g.tags, "tags", "", "space-separated list of Go build tags to be ORed together in generated files")
 	flagTarget := fs.String("target", "bpfel,bpfeb", "clang target(s) to compile for (comma separated)")
 	fs.StringVar(&b2g.makeBase, "makebase", "", "write make compatible depinfo files relative to `directory`")
 	fs.Var(&b2g.cTypes, "type", "`Name` of a type to generate a Go declaration for, may be repeated")
@@ -261,7 +261,8 @@ type bpf2go struct {
 	skipGlobalTypes bool
 	// C types to include in the generatd output.
 	cTypes cTypes
-	// Go tags included in the .go
+	// Go tags included in the .go output. Must be space-separated and will be
+	// ORed together.
 	tags string
 	// Base directory of the Makefile. Enables outputting make-style dependencies
 	// in .d files.
@@ -292,12 +293,13 @@ func (b2g *bpf2go) convert(tgt target, arches []string) (err error) {
 		return err
 	}
 
-	var tags []string
+	// Strings in the inner slice will be ORed, all outer items will be ANDed.
+	var tags [][]string
 	if len(arches) > 0 {
-		tags = append(tags, strings.Join(arches, " "))
+		tags = append(tags, arches)
 	}
 	if b2g.tags != "" {
-		tags = append(tags, b2g.tags)
+		tags = append(tags, strings.Split(b2g.tags, " "))
 	}
 
 	cFlags := make([]string, len(b2g.cFlags))

diff --git a/cmd/bpf2go/output.go b/cmd/bpf2go/output.go
@@ -19,9 +19,7 @@ import (
 const ebpfModule = "github.com/cilium/ebpf"
 
 const commonRaw = `// Code generated by bpf2go; DO NOT EDIT.
-{{- range .Tags }}
-// +build {{ . }}
-{{- end }}
+//go:build {{ join .Tags }}
 
 package {{ .Package }}
 
@@ -161,8 +159,9 @@ var {{ .Name.Bytes }} []byte
 `
 
 var (
-	tplFuncs = map[string]interface{}{
-		"tag": tag,
+	tplFuncs = template.FuncMap{
+		"tag":  tag,
+		"join": joinBuildTags,
 	}
 	commonTemplate = template.Must(template.New("common").Funcs(tplFuncs).Parse(commonRaw))
 )
@@ -220,7 +219,7 @@ func (n templateName) CloseHelper() string {
 type outputArgs struct {
 	pkg             string
 	ident           string
-	tags            []string
+	tags            [][]string
 	cTypes          []string
 	skipGlobalTypes bool
 	obj             string
@@ -299,7 +298,7 @@ func output(args outputArgs) error {
 		*btf.GoFormatter
 		Module    string
 		Package   string
-		Tags      []string
+		Tags      [][]string
 		Name      templateName
 		Maps      map[string]string
 		Programs  map[string]string
@@ -382,3 +381,13 @@ func sortTypes(typeNames map[btf.Type]string) ([]btf.Type, error) {
 func tag(str string) string {
 	return "`ebpf:\"" + str + "\"`"
 }
+
+// joinBuildTags joins all inner strings by " || ", all outer strings by ") && (", and
+// wraps the whole string in ().
+func joinBuildTags(tags [][]string) string {
+	var and []string
+	for _, or := range tags {
+		and = append(and, strings.Join(or, " || "))
+	}
+	return fmt.Sprintf("(%s)", strings.Join(and, ") && ("))
+}
diff --git a/cmd/bpf2go/test/test_bpfeb.go b/cmd/bpf2go/test/test_bpfeb.go
diff --git a/cmd/bpf2go/test/test_bpfel.go b/cmd/bpf2go/test/test_bpfel.go
diff --git a/examples/cgroup_skb/bpf_bpfeb.go b/examples/cgroup_skb/bpf_bpfeb.go
diff --git a/examples/cgroup_skb/bpf_bpfel.go b/examples/cgroup_skb/bpf_bpfel.go
diff --git a/examples/fentry/bpf_bpfeb.go b/examples/fentry/bpf_bpfeb.go
diff --git a/examples/fentry/bpf_bpfel.go b/examples/fentry/bpf_bpfel.go
diff --git a/examples/kprobe/bpf_bpfeb.go b/examples/kprobe/bpf_bpfeb.go
diff --git a/examples/kprobe/bpf_bpfel.go b/examples/kprobe/bpf_bpfel.go
diff --git a/examples/kprobe_percpu/bpf_bpfeb.go b/examples/kprobe_percpu/bpf_bpfeb.go
diff --git a/examples/kprobe_percpu/bpf_bpfel.go b/examples/kprobe_percpu/bpf_bpfel.go
diff --git a/examples/kprobepin/bpf_bpfeb.go b/examples/kprobepin/bpf_bpfeb.go
diff --git a/examples/kprobepin/bpf_bpfel.go b/examples/kprobepin/bpf_bpfel.go
diff --git a/examples/ringbuffer/bpf_bpfeb.go b/examples/ringbuffer/bpf_bpfeb.go
diff --git a/examples/ringbuffer/bpf_bpfel.go b/examples/ringbuffer/bpf_bpfel.go
diff --git a/examples/tcprtt/bpf_bpfeb.go b/examples/tcprtt/bpf_bpfeb.go
diff --git a/examples/tcprtt/bpf_bpfel.go b/examples/tcprtt/bpf_bpfel.go
diff --git a/examples/tcprtt_sockops/bpf_bpfeb.go b/examples/tcprtt_sockops/bpf_bpfeb.go
diff --git a/examples/tcprtt_sockops/bpf_bpfel.go b/examples/tcprtt_sockops/bpf_bpfel.go
diff --git a/examples/tcprtt_sockops/main.go b/examples/tcprtt_sockops/main.go
@@ -1,5 +1,4 @@
 //go:build linux
-// +build linux
 
 // This program demonstrates attaching an eBPF program to
 // a cgroupv2 path and using sockops to process TCP socket events.

diff --git a/examples/tracepoint_in_c/bpf_bpfeb.go b/examples/tracepoint_in_c/bpf_bpfeb.go
diff --git a/examples/tracepoint_in_c/bpf_bpfel.go b/examples/tracepoint_in_c/bpf_bpfel.go
diff --git a/examples/uretprobe/bpf_bpfel_x86.go b/examples/uretprobe/bpf_bpfel_x86.go
diff --git a/examples/xdp/bpf_bpfeb.go b/examples/xdp/bpf_bpfeb.go
diff --git a/examples/xdp/bpf_bpfel.go b/examples/xdp/bpf_bpfel.go